No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Effects of Cell Phone Radiofrequency Signal Exposure on Brain Glucose Metabolism
Abstract
The dramatic increase in use of cellular telephones has generated concern about possible negative effects of radiofrequency signals delivered to the brain. However, whether acute cell phone exposure affects the human brain is unclear.
To evaluate if acute cell phone exposure affects brain glucose metabolism, a marker of brain activity.
Randomized crossover study conducted between January 1 and December 31, 2009, at a single US laboratory among 47 healthy participants recruited from the community. Cell phones were placed on the left and right ears and positron emission tomography with ((18)F)fluorodeoxyglucose injection was used to measure brain glucose metabolism twice, once with the right cell phone activated (sound muted) for 50 minutes ("on" condition) and once with both cell phones deactivated ("off" condition). Statistical parametric mapping was used to compare metabolism between on and off conditions using paired t tests, and Pearson linear correlations were used to verify the association of metabolism and estimated amplitude of radiofrequency-modulated electromagnetic waves emitted by the cell phone. Clusters with at least 1000 voxels (volume >8 cm(3)) and P < .05 (corrected for multiple comparisons) were considered significant.
Brain glucose metabolism computed as absolute metabolism (μmol/100 g per minute) and as normalized metabolism (region/whole brain).
Whole-brain metabolism did not differ between on and off conditions. In contrast, metabolism in the region closest to the antenna (orbitofrontal cortex and temporal pole) was significantly higher for on than off conditions (35.7 vs 33.3 μmol/100 g per minute; mean difference, 2.4 [95% confidence interval, 0.67-4.2]; P = .004). The increases were significantly correlated with the estimated electromagnetic field amplitudes both for absolute metabolism (R = 0.95, P < .001) and normalized metabolism (R = 0.89; P < .001).
In healthy participants and compared with no exposure, 50-minute cell phone exposure was associated with increased brain glucose metabolism in the region closest to the antenna. This finding is of unknown clinical significance.
... watt), a form of nonionizing electromagnetic radiation that can be absorbed by tissues that are close to the phone. Mobile phone technology creates an electromagnetic field (EMF) in two ways: 1. Via base stations and 2. Via the phones themselves (2) . ...
... The amount of RF energy a mobile phone user is exposed to depends on many factors such as the technology of the phone, the distance between the phone and the user, duration of use, the extent of mobile phone usage, and the users distance from the base stations (2) . ...
... The International Agency for Research on Cancer classifies radio-frequency EMFs as possible carcinogens (2) . In studies on the side effects of EMFs on health, it has been shown EMF has been associated with many diseases such as Alzheimer's disease, autism, blood-brain barrier damage, brain tumors, depression, suicide, DNA damage, fatigue, headache and migraine, heart diseases, hormonal imbalance, joint pain, upper respiratory tract infections, immune system disorders, high blood pressure, learning difficulties, leukemia, loss of concentration, decreased sperm count, miscarriages, Parkinson's disease, sleep disorders and insomnia (3)(4)(5)(6)(7)(8)(9)(10)(11)(12) . ...
... watt), a form of nonionizing electromagnetic radiation that can be absorbed by tissues that are close to the phone. Mobile phone technology creates an electromagnetic field (EMF) in two ways: 1. Via base stations and 2. Via the phones themselves (2) . ...
... The amount of RF energy a mobile phone user is exposed to depends on many factors such as the technology of the phone, the distance between the phone and the user, duration of use, the extent of mobile phone usage, and the users distance from the base stations (2) . ...
... The International Agency for Research on Cancer classifies radio-frequency EMFs as possible carcinogens (2) . In studies on the side effects of EMFs on health, it has been shown EMF has been associated with many diseases such as Alzheimer's disease, autism, blood-brain barrier damage, brain tumors, depression, suicide, DNA damage, fatigue, headache and migraine, heart diseases, hormonal imbalance, joint pain, upper respiratory tract infections, immune system disorders, high blood pressure, learning difficulties, leukemia, loss of concentration, decreased sperm count, miscarriages, Parkinson's disease, sleep disorders and insomnia (3)(4)(5)(6)(7)(8)(9)(10)(11)(12) . ...
... Изследвания показват, че RF-EMF, излъчвани от мобилни телефони, активират метаболитните процеси в човешкия мозък (Volkow, Tomasi, Wang et al., 2011) и влияят на невронната активност у човека (Jeong, Kang, Kwon et al., 2015). Влиянието на нейонизиращата радиация води до повишени нива на алфа-амилазата в човешката слюнка, тревожност, фобична тревожност, обсесивнокомпулсивно разстройство, високи нива на соматоморфни разстройства и т.н. ...
... Някои от ефектите върху хората след излагане на импулсни електромагнитни полета, генерирани от стандартен мобилен телефон, включват намаляване на когнитивните показатели (Maier, Greter, Maier, 2004), както и необходимостта от повече време за отговор на дадена задача, когато GSM апаратът е в близост до главата (Luria, Eliyahu, Hareuveny et al., 2009). Според (Volkow, Tomasi, Wang, 2011) мозъчният метаболизъм в областта, близка до антената на мобилния телефон, е значително поинтензивен и корелира с по-високата стойност на ЕМП. Въпреки че в проучването не се посочва влиянието върху здравето, резултатите показват, че излагането на радиочестотни електромагнитни полета от мобилни телефони влияе върху мозъчната функция (Volkow, Tomasi, Wang, 2011). ...
... Според (Volkow, Tomasi, Wang, 2011) мозъчният метаболизъм в областта, близка до антената на мобилния телефон, е значително поинтензивен и корелира с по-високата стойност на ЕМП. Въпреки че в проучването не се посочва влиянието върху здравето, резултатите показват, че излагането на радиочестотни електромагнитни полета от мобилни телефони влияе върху мозъчната функция (Volkow, Tomasi, Wang, 2011). В (Гарванов, Гарванова, 2016Garvanova, Garvanov, Borissova, 2020) са проведени задълбочени изследвания за термалния ефект върху тялото на човека, предизвикан от използването на мобилни телефони. ...
... During fetal development and early childhood, there are embryonic and adult stem cells which are more sensitive to electromagnetic waves 2, 3,4 .In 2011, Volkow et al conducted a study taking PET scan of the brain while the person was talking on mobile held up to the ear. High rates of glucose consumption were noticed by the part of the brain close to the mobile phone as compared to the rest of the brain 5 . This spike in brain activity due to electromagnetic waves from the cell phone may permanently alter brain function 6,7 . ...
... This spike in brain activity due to electromagnetic waves from the cell phone may permanently alter brain function 6,7 . Children's brain is still developing and many neurological connections are being formed over time and this exposure may delete synaptic connections hence it's an area of great concern 5 . An ipsilateral acoustic neuroma and glioma of the brain after 10-year use of mobile phone was also reported 8 . ...
... However, there is an increasing report of sensitivity to cellphone radiation, with symptoms such as ringing in the ears, headaches, dizziness, irregular heartbeat, memory and sleep problems which has been labeled as electromagnetic hypersensitive syndrome (EHS) and has been linked to prolonged exposure. These effects can be traced to the circulation rate of high technology cellphones that are mostly powered at higher radiofrequency (3G, 4G and 5G networks) for better and faster internet connectivity when compared to traditional landlines and the alternative mobile telecommunication service known as Code Division Multiple Access (CDMA) phones, which are operated via 2G technologies for voice communication (Volkow, 2011) (Kuehn et al, 2013). ...
... Hence, preventative health warnings are being adopted and disseminated to encourage and protect cellphone users and FCC website offers several basic techniques for reducing mobile radiation exposure. Therefore, all countries should review their cellphone regulatory standards and assessment processes in order to safeguard their citizens from avoidable threats (Volkow et al, 2011). Furthermore, governments must provide ample warnings to cellphone users on how to use their phones safely, such as in Belgium, where children are prohibited from using phones and other phone users are advised to choose phones with a lower specific absorption rate (SAR), and several other countries have strict SAR limits, such as the requirement that phone providers state SAR on every cellphone produced. ...
In today’s world, advancements in technology have benefited the society socially and
economically. Several technological devices play important roles in our daily lives.
However, as electronics and communication technologies improve, there is a greater risk
of exposure to electromagnetic fields, which can cause a variety of health problems in
individuals. Sources of these electromagnetic waves includes power transmission lines,
base transmitter stations, mobile phones, medical treatment techniques and household
gadgets, and the waves released from these sources are absorbed by the body, generating a
variety of side effects. Different studies have found that exposure to radiofrequency
radiation from the sources mentioned earlier raises the risk of various cancers not only
women and children. Radio-waves can also causes changes in Electroencephalography
(EEG) and Electrocardiography (ECG) patterns, as well as decreases in prolactin,
testosterone, estrogen, and progesterone levels. Long-term exposure to radio- waves has
been shown in studies to cause low sperm count in men. This report analyses the available
literature on the health implications of radio-waves on human body so as to proffer practical
suggestions for proper usage of devices emitting this radiation.
... 11,12 Las ondas electromagnéticas no ionizantes representan una de las principales fuentes de contaminación ambiental, siendo uno de los más relevantes ejemplos, la actualidad es el incremento en el uso de los teléfonos móviles, los cuales se utilizan cerca del cerebro, por lo que su uso continuo produce desde trastornos del sueño. [13][14][15] Sin embargo, aunque los estudios realizados no han destacado la posibilidad de que el uso del teléfono celular sea una causa de cáncer Dominique Belpomme et al. 14 15 han mostrado modificaciones en las funciones cerebrales, en concreto, Volkow mostró un incremento en la metabolización de la glucosa en el cerebro del lado donde se presentaba el aparato. Es por ello, que entre varias actividades que se han realizado para estudiar y prevenir los efectos de la radiación no ionizante, se formó la International Commission On Non-Ionizing Radiation Protection (CNIRP-https://www.icnirp.org/en/frequencies/index.html). ...
... 11,12 Las ondas electromagnéticas no ionizantes representan una de las principales fuentes de contaminación ambiental, siendo uno de los más relevantes ejemplos, la actualidad es el incremento en el uso de los teléfonos móviles, los cuales se utilizan cerca del cerebro, por lo que su uso continuo produce desde trastornos del sueño. [13][14][15] Sin embargo, aunque los estudios realizados no han destacado la posibilidad de que el uso del teléfono celular sea una causa de cáncer Dominique Belpomme et al. 14 15 han mostrado modificaciones en las funciones cerebrales, en concreto, Volkow mostró un incremento en la metabolización de la glucosa en el cerebro del lado donde se presentaba el aparato. Es por ello, que entre varias actividades que se han realizado para estudiar y prevenir los efectos de la radiación no ionizante, se formó la International Commission On Non-Ionizing Radiation Protection (CNIRP-https://www.icnirp.org/en/frequencies/index.html). ...
Los seres vivos estamos expuestos de manera natural a una forma de energía denominada radiación. La característica de la radiación que más dificulta su comprensión es que en su mayoría es invisible al ojo humano. Esta presenta su origen en la propia naturaleza que nos rodea; la radiación cósmica procede del sol y del resto del universo, la vida en nuestro planeta se ha desarrollado en un entorno cruzado incesantemente por radiaciones. De forma continua, todos los seres vivos, incluido el hombre, reciben radiaciones, que pueden ser inocuas o francamente nocivas a su sistema. La forma de radiación más generalizada es la procedente del sol, sin embargo, un exceso de ella puede causar lesiones importantes, aunque se sospecha que prácticamente todas las formas de radiaciones pueden ser nocivas en una situación concreta, la mayor parte de la atención acerca de los efectos nocivos de las radiaciones ha sido atraída por un tipo especial de radiaciones de elevada energía que es capaz de originar partículas cargadas “iones” a partir de los átomos en que incide, y que recibe por ello el nombre de radiación ionizante, de igual importancia se encuentran la radiación no ionizante la cual no presenta la suficiente energía para producir la ionización de las moléculas o átomos.
... Radiation Exposure (Kesari & Behari, n.d., 2012b; Volkow et al., 2011) [15,29] Mitigation strategies for reducing mobile phone radiation exposure involve various measures that can help limit exposure to the radiation emitted by mobile phones. These strategies can be divided into two categories: personal measures and technological measures. ...
... Radiation Exposure (Kesari & Behari, n.d., 2012b; Volkow et al., 2011) [15,29] Mitigation strategies for reducing mobile phone radiation exposure involve various measures that can help limit exposure to the radiation emitted by mobile phones. These strategies can be divided into two categories: personal measures and technological measures. ...
With the widespread use of mobile phones, concerns have been raised about the potential health effects of exposure to their radiation. This review aims to provide an overview of the current knowledge on the effects of mobile phone radiation on human health. Various studies have investigated the impact of mobile phone radiation on different aspects of human health, including reproductive health, neurological function, hormonal imbalance and cancer. The results of these studies have been inconsistent, and further research is needed to establish a conclusive link between mobile phone radiation and adverse health effects. The review discusses the current understanding of the mechanisms underlying the potential health effects of mobile phone radiation and highlights the need for continued research in this field.
... Recent findings suggest highlight concerns surrounding the potentially deleterious effects of chronic and long-term exposure to the radio (RF), Bluetooth, and WIFI frequencies on biological and brain systems. Detrimental effects are generally considered to be dependent on the distance and relative size of a given object, but also on the environmental parameters, and there may be additional interindividual differences in sensitivities to RF, making the assessment of these risks difficult (Krause et al., 2006;Hung et al., 2007;Croft et al., 2010;Ishak et al., 2011;Volkow et al., 2011;Avendaño et al., 2012;Balachandran et al., 2012;Laudisi et al., 2012;Megha et al., 2012Megha et al., , 2015Banaceur et al., 2013;Kesari et al., 2013;Shahin et al., 2013;Mandalà et al., 2014;Saili et al., 2015;Mohan et al., 2016;Othman et al., 2017). Wearable neurotechnologies concentrate ...
... Detrimental effects are generally considered to be dependent not only on the distance and relative size of a given object but also on the environmental parameters, and there may be additional interindividual differences in sensitivities to exposure, making the assessment of these risks difficult. However, research suggests that regular and long-term use of RF emitting devices (especially at close distance to the body) can have a negative impact on biologic systems, most notably on the brain (Ishak et al., 2011;Volkow et al., 2011;Avendaño et al., 2012;Megha et al., 2012Megha et al., , 2015Atasoy et al., 2013;Kesari et al., 2013;Shahin et al., 2013). Wearable neurotechnologies concentrate RF energy from bluetooth and Wi-Fi in and around the area of the brain in larger amplitudes than has been studied previously. ...
Over the last 30 years we have observed dramatic declines in mental health worldwide, with nearly 450 million people currently suffering from a mental or behavioral disorder. Globally, there is less than 1 mental health professional for every 10,000 people, with 76-85% of the population in low and middle-income countries without access to treatment. The overarching aim of this thesis is the identification of novel and cost-effective methods for measuring, detecting, and assessing well-being. In the first study of this research project, we validated the ability of a quick global scale to capture multidimensional well-being on 1,615 participants that participated in an online survey, identified some predictors of well-being, and observed improvements from online interventions. Mental health and individual well-being also influences the structure and function of our brains across the lifespan, which in turn, mediate well-being levels. While progress has been made regarding our understanding of the interacting relationships between well-being and brain function, much is still unknown. Recent technological advances have led to the development of affordable, light-weight, wearable, and wireless electroencephalography (EEG) technologies that offer fast preparation time, high mobility, and that facilitate the collection of EEG data over large and diversified populations by increasing access to populations that were previously difficult to study with conventional systems. The analysis of large datasets with robust statistical methods or advanced machine-learning algorithms can ease the identification of trends, the mediator role of covariables, and the classification of mental states. While low-cost, low-density EEG systems have presented significant challenges for conducting EEG research, here we validated a wearable system for recording spectral measures relevant to the study of well-being, by comparison with a state-of-the-art system (study 2). In study 3, we used the tools validated in studies 1 and 2 to examine the relation between EEG and multidimensional well-being in a large sample (N = 353). We found a potential EEG marker of well-being, consistent with some literature on anxiety and depression, with age as a mediator. We discuss interpretations and limitations related to the studies and the broader field, as well as future directions (e.g., real-world EEG monitoring, dyadic or multimodal applications, brain-computer interfaces, neurofeedback training) and ethical implications for the field. The broader applications of this line of research will hopefully help to reduce the prevalence of mental health disparities worldwide (e.g., chronic stress, anxiety disorder, depression, psychiatric conditions), and will also help to predict and prevent mental illness in the broader population.
... Possible effects of RF radiation on the brain (and the nervous system in general) have been the focus of particular attention because of the concern that the electrical properties of neurons might render them especially vulnerable to electromagnetic radiation. The advent of cellular communications and the omnipresence of cell phones has lent new urgency to research on the effects of RF fields on brain tissue [4][5][6][7][8] . Since RF fields are also used in magnetic resonance imaging (MRI), RF effects on the brain have also been explored in the imaging literature 9,10 . ...
... Non-thermal effects of RF stimulation. The "non-thermal" vs. "thermal" debate about the effects of electromagnetic fields on biological systems has a long history in microwave and radiofrequency radiation research [4][5][6][7][8][9] . Using a modified fiber-coupled version of the UCLA Miniscope, our interference-and artifactfree experiments provide a ground truth for this question. ...
As the use of Radio Frequency (RF) technologies increases, the impact of RF radiation on neurological function continues to receive attention. Whether RF radiation can modulate ongoing neuronal activity by non-thermal mechanisms has been debated for decades. However, the interactions between radiated energy and metal-based neural probes during experimentation could impact neural activity, making interpretation of the results difficult. To address this problem, we modified a miniature 1-photon Ca2+ imaging device to record interference-free neural activity and compared the results to those acquired using metal-containing silicon probes. We monitored the neuronal activity of awake rodent-brains under RF energy exposure (at 950 MHz) and in sham control paradigms. Spiking activity was reliably affected by RF energy in metal containing systems. However, we did not observe neuronal responses using metal-free optical recordings at induced local electric field strengths up to 230 V/m. Our results suggest that RF exposure higher than levels that are allowed by regulatory limits in real-life scenarios do not affect neuronal activity. Omid Yaghmazadeh and colleagues explore non-thermal responses to RF radiation in live rodent brains using electrophysiology and 1-photon Ca2+ imaging. They saw no impact of RF energy in metal-free recordings at levels higher than regulatory limits.
... Over the past decade, scientific research on EHS has progressed significantly. Several studies in research fields such as brain metabolism, immunology, cancer research, sleep research and genetics suggest that EHS is indeed a genuine biomedical phenomenon with significant implications for health and well-being (Auvinen et al., 2019;Cho et al., 2017;Christopher et al., 2020;Kim, Kabir, and Jahan, 2016;Lin, 2016;Nadeem, Raghuwanshi, Yadav, and Anjum, 2019;Siqueira et al., 2016), rather than a psychological or psychosomatic disorder (Belpomme, Campagnac, and Irigaray, 2015;Carlberg and Hardell, 2017;Kimata, 2005;Myers, 2017;Schmid et al., 2012;Volkow et al., 2011;Zothansiama, Zosangzuali, Lalramdinpuii, and Jagetia, 2017). For instance, the comprehensive review by Belpomme and Irigaray (2022), point to pathophysiological factors linking RF-EMF exposure to inflammation, abnormalities in neurotransmitters, oxidative stress, and changes in the blood-brain barrier, indicating underlying neurobiological dysfunctions. ...
... The nervous system is sensitive to EMFs (Bertagna et al., 2021). Cell phone radiation has been found to alter brain activity (Volkow et al., 2011, Bin et al., 2014, impact neurotransmitters and alter neuron development (Kaplan et al., 2015, Li et al., 2021, Chen et al., 2021. Teenagers were found to experience memory damage to the area of the brain most exposed to cell phone radiation after just one year (Foerster et al., 2018). ...
This chapter introduces what EMFs are, how people are exposed, science documenting health effects of exposure, U.S. and international policy on protection from EMFs and nursing implications for clinical practice and
advocacy in concert with Alliance of Nurses for Healthy Environments' principles.
... With the increasing awareness of people's health, researches on the relationship between electromagnetic fields and human health have also received sustained attention. Radiofrequency fields generated by antennas accelerated glucose metabolism in the human brain [6] and they have no impact on human health when considering the basal metabolism of the human body [7]. The maximum value of human specific absorption rate (SAR) from EMFs generated by V2V (vehicle-to-vehicle) antennas on smart cars occurred at the skin tissue closest to the exposed source but did not exceed the International Commission on Non-Ionizing Radiation Protection (ICNIRP) criteria [8]. ...
In China, high-speed trains have become a major means of transportation for the masses. When the passengers wearing pacemakers travel on high-speed trains, electromagnetic environment in the carriage where the GSM-R voice and data antennae are located should be concerned. In this work, a real-size carriage monopole antennae simulating voice and data antennae as high-frequency radiation sources and wearing pacemaker passenger’ models were established to study the electromagnetic exposure of the passenger at different conditions. The results showed that when the passenger faced the voice antenna, he suffered much greater electromagnetic radiation than when his back in turned from it. The electric field strength, average SAR, and temperature rise of the heart when facing the antenna were 27.3 V/m, 0.0102 W/kg, and 0.0016°C, respectively. Meanwhile, the temperature rise of the pacemaker was 0.001°C. We also obtained the values of electromagnetic dose for the whole body. All data were below the limits of the ICNIRP guidelines. These results indicate that the electromagnetic fields generated by the GSM-R voice and data antennae do not harm the health of passengers wearing pacemaker.
... One of the main risks associated with them is the potential for exposure to electromagnetic radiation, including radiofrequency (RF) and EMF [3]. Studies have shown that prolonged exposure to RF-EMF can cause a range of adverse health effects, including increased risk of certain types of cancer, decreased fertility, and neurological problems [3,4]. Furthermore, research has also suggested that children and adolescents may be particularly susceptible to the effects of RF-EMF, as their bodies are still developing and their skulls are thinner than those of adults [2,5]. ...
Background: The exponential growth in mobile phone usage has raised concerns about electromagnetic field (EMF) exposure and its health risks. Blood pressure and BMI, which impair heart function due to decreased adrenoreceptor responsiveness, parasympathetic tone withdrawal, and increased sympathetic activity, may further exacerbate these risks. However, the effects of radiofrequency electromagnetic (RF-EM) exposure from mobile phones on electrocardiograms (ECGs) and heart rate variability (HRV) in individuals remain unclear.
Purpose: Building upon our previous findings on HRV changes due to mobile phone proximity, this study is aimed at significantly enhancing the analytical approach used to assess the effects of mobile phones on cardiac parameters. This study exploits data from a previous study but with a different purpose. The aim of this study is twofold: (a) to examine whether exposure to mobile phones changes the five variables (P-R, QRS, QT, ST, and HR) in a multivariate manner and (b) to examine whether the blood pressure and/or the body mass index (BMI), which acts as a proxy for obesity, have an effect on the change of these five variables. For both aspects of the study, four cycles are performed.
Method: We conducted multivariate analysis on previously collected electrical cardiac measurement data from 20 healthy male subjects exposed to mobile phone EMF, with the mobile phones placed at four different body locations. The one-sample Hotelling T2 test on the mean vector of differences was utilised instead of multiple paired t-tests. This multivariate method comprehensively analyzes data features and accounts for variable correlations, unlike multiple univariate analyses. Given our small sample size, we employed the MMPC variable selection algorithm to identify predictor variables significantly related to mean changes.
Results: Significant alterations in ECG intervals and heart rate were noted in the subjects before and after the first EMF exposure cycle, independent of their BMI. Notably, heart rate, P-R, and QRS intervals fell postexposure while QT and ST intervals increased. These changes were influenced by variations in systolic blood pressure, with BMI showing no significant effect.
Conclusion: The observed modifications in cardiac electrical measurements due to mobile phone EMF exposure are attributed to the effects of EMF itself, with no impact from BMI on the extent of these changes.
... 6(Si2) (2024) varies. The central nervous system, testis and lens of the eye seem to be especially delicate, because of a restricted ability to disperse heat eyes are more susceptible to heat-induced damage [15,16]. Thermal effects from microwave radiation have been reported to cause cataract and have adverse effects for the cornea, retina and other ocular systems, but effects of non-thermal radiations are not well understood [17]. ...
Radiofrequency (RF) energy causes various side effects including
cataracts and have some undesirable effects on retina and cornea.
However it is still uncertain whether the amplitude-modulated RF
signals from digital phones exert similar bio effects compared to that
of continuous (unpopulated) RF radiation though the increase use of
cellular phone generate concern to health. The purpose of the study is
to assess the impact of RF radiation emitted by smartphones on
dioptric power of the eye. Total 50 healthy male and female adult
volunteers were recruited for this study between the age group 18-40
years. The Dioptric value of the subjects was recorded prior to study.
After an interval of 30 days, the Dioptric values were recorded again
for the assessment. Similarly, Visual acuity, Retinoscopy readings
and keratometer reading were recorded. The study suggests that there
are certain changes in parameters in the subjects after exposure to RF
radiation. We can conclude prolonged use of smartphones in daily
life may have a negative effect on the eyes and dioptric values
changes with higher exposure to RF.
Keywords: Dioptric power; Radio frequency; Refractive error.
Radiation frequency; Smartphone radiation
... There have been long-standing concerns about the adverse health effects of various types of RF-EMR (Li and Wu 2023;Yang et al. 2019). Research has shown that RF-EMR can accelerate glucose metabolism in the brain (Volkow et al. 2011), weaken the blood-brain barrier (Tang et al. 2015), cause changes in the morphology and structure of cells in the hippocampus and cerebral cortex, and subsequently damage the brain's central nervous system, leading to various neurological disorders such as anxiety and memory impairment (Aldad et al. 2012;Li et al. 2012;Ntzouni et al. 2011;Sharma et al. 2017). Anxiety is a common emotion in everyday life. ...
Modern life is filled with radiofrequency electromagnetic radiation (RF-EMR) in various frequency bands, while the health risks are not clear. In this study, mice were whole-body exposed to 0.9/1.5/2.65 GHz radiofrequency radiation at 4 W/kg for 2 h per day for 4 weeks to investigate the emotional effects. It was found that the mice showed anxiety but no severe depression. The ELISA results showed a significant decrease in amino acid neurotransmitters (GABA, DA, 5-HT), although acetylcholine (ACH) levels were not significantly altered. Furthermore, Western blot results showed that BDNF, TrkB, and CREB levels were increased in the cerebral cortex, while NF-κB levels were decreased. In addition, pro-inflammatory factors (IL-6, IL-1β, TNF-α) were significantly elevated, and anti-inflammatory factors (IL-4, IL-10) tended to decrease. In conclusion, multi-frequency electromagnetic radiation induces an inflammatory response through the CREB-BDNF-TrkB and NF-κB pathways in the cerebral cortex and causes a decrease in excitatory neurotransmitters, which ultimately causes anxiety in mice.
... [10][11][12] In fact, the evidence from brain imaging also indicates that EMF from devices like mobile phones can alter the regional cerebral blood flow, sleep, and waking EEG of the participants. [13][14][15][16] Regulatory authorities worldwide have suggested precautions and have set stringent criteria for managing EMF exposures from emerging wireless technologies as they may pose a serious threat to public health consequences. 17 The Enviroglobe invented by Syenergy Environics, Gurugram, India uses technology involving an array of crystals, that may alter the nature of digital smog waveforms from constant to random, making them less harmful to humans. ...
... All mobile devices emit RF radiation when transmitting wireless signals. The amount of RF radiation in a mobile phone depends on the company that produces it, the technology used, the distance the user keeps while using the handset, and the distance from where the signal is received (Volkow et al., 2011). A mobile device's SAR rating is used to estimate the amount of RF absorbed by a user's head and body when using the device. ...
Internet technology has become an integral part of human life today. The mobile phone is an inevitable tool to access this technology at the fingertips. Unlike the yesteryears, the cost of mobile phone manufacturing and the related technology, the subscription money to the network has dropped considerably. These facilitate people to have easy access to this modern-day technological gadget, the mobile phone. However, many people are not serious about the harmful effects of mobile phones, especially the radiation by these gadgets. This cross-sectional study focused on the mobile phone radiation among college students in Nagaland. Specifically, the study focused on the knowledge and awareness of the radiation emitted by their mobile phones and the precautionary measures taken by the college students to reduce radiation hazards. INTRODUCTION: The telephone is undoubtedly one of the greatest inventions of humans in recent centuries. Telephones enable us to reach out to family, friends, and others and to communicate easily with people who live faraway places. With this communicative technology, the world has become closer to reaching out to our fellow beings. This communication technology has evolved one-step further today. From simple telephones, we have smartphones, and they dominate the whole world of information. Smartphones use radiofrequency radiation (RF) to send signals and have become an inevitable tool for communication and information. It is ahead of technology and provides all the information at our fingertips.
... In patients already diagnosed with multiform glioblastoma, which is the brain tumor with the worst prognosis, the usage of cellphones longer than 3 hours a day has been related with a higher chances of medication resistance, also with mutations on p53 with cell cycle abnormalities [12]. ...
... Mobilné telefóny vyžarujú vysokofrekvenčnú energiu, čo je formou neionizujúceho elektromagnetického žiarenia, ktoré môže byť absorbované tkanivami nachádzajúcimi sa v blízkosti mobilného zariadenia. Množstvo rádiofrekvenčnej energie, ktorému je užívateľ vystavený, závisí od množstva faktorov, ako napríklad samotná technológia telefónu, vzdialenosť medzi užívateľom a telefónom alebo rozsah a frekvencia využívania mobilného telefónu (Volkow, Tomasi & Wang, et al., 2011). V roku 2011 Medzinárodná agentúra pre výskum rakoviny (IARC) klasifikovala žiarenie mobilných telefónov ako karcinogénne, čo znamená, že je v tomto prípade určité riziko karcinogenity (Frei, Poulsen & Johansen, et al., 2011). ...
... Thus the visible part (light) of the electromagnetic spectrum was used. The electromagnetic spectrum outside the visible area has been used as a more recent means of communication through radio (radio communications) [1][2][3]. ...
Wireless communications are characterized by their fastest growth in history, as they used ever-evolving and renewed technologies, which have allowed them to spread widely. Every day, communication technology introduces a new invention with features that differ from its predecessor. Bell Laboratories first suggested mobile wireless communication services to the general population in the late 1940s. Still, it wasn't easy at that time to use on a large scale due to its high costs. This paper aims to describe the state of cellular mobile networks; by comparing the sources of electromagnetic pollution caused by these networks, measure the level of power density in some residential areas, and compare them with international standards adopted in determining the level of power density by calculating the effect of the transmitted power and the angle of transmission of the antenna from the station. The importance of the paper lies in the fact that it investigates the levels of non-ionizing radiation produced by cellular mobile networks and the identification of other types of pollution caused by these networks.
... The biological consequences of exposure to radio fr-equencies are controversial [5]. Decades of research have yielded conflicting results; for instance, the results of some studies were reported the existence of a causal relationship between exposure to radiofrequency electromagnetic fields with an increased risk of glioma, meningioma, infertility, and deafness [6][7][8][9]. However, the findings of other studies could not confirm these results [10][11][12]. ...
Statement of the problem:
Mobile usage has increased worldwide over the past two decades. There are conflicting reports about the carcinogenic effects of cell phone radiation on the oral mucosa. Micronucleus (MN) is considered a reliable marker for genotoxic damage.
Purpose:
This study aimed to identify the impact of mobile phone radiation on the MN frequency in oral mucosal cells.
Materials and method:
In this descriptive-analytical study, 50 mobile phone users between the age group of 20-38 years were included. Samples were obtained from the right and left cheek mucosa of each subject (a total 100 cell samples). Every participant filled out a questionnaire about his or her cell phone usage habits. Additionally, personal information such as age, gender, and body mass index (BMI) were assessed. The Feulgen and Papanicolaou staining methods were used for staining of the cell samples. A total of 1000 cells in each sample were evaluated for MNs.
Results:
The mean number of MN in exposed and non-exposed mucosa by Feulgen method was 0.71±1.13 and 0.57±1.36, respectively. Also in Papanicolaou staining, the mean number of MN in the exposed mucosa and non-exposed mucosa was 6.94±6.61 and 6.54±6.88, respectively, but these differences were not significant (p> 0.05). The frequency of MN in non-specific DNA staining was significantly (5- to 6-fold) higher than DNA-specific staining. We observed no statically significant differences between MN frequency according to age, gender, BMI, and other cell phone usage habits (p> 0.05).
Conclusion:
This study showed that cell phone use does not cause genotoxic effects in the buccal mucosa in the oral cavity. Moreover, using non-specific DNA staining methods can increase the frequency of MN by more than 5- to 6-fold.
... The placement of cell phones against the head made the nervous system a primary target, and epidemiological observations were quick to document cancer risks [98]. These risks correlated with mobile phone use, changes in metabolism [99] and the generation of ROS [100]. Even while considering heat only as a risk, anticipated health impacts from RFR prompted the industry to conduct tests designed to limit the heating of the brain by RFR. ...
In the 1990s, the Institute of Electrical and Electronics Engineers (IEEE) restricted its risk assessment for human exposure to radiofrequency radiation (RFR) in seven ways: (1) Inappropriate focus on heat, ignoring sub-thermal effects. (2) Reliance on exposure experiments performed over very short times. (3) Overlooking time/amplitude characteristics of RFR signals. (4) Ignoring carcinogenicity, hypersensitivity, and other health conditions connected with RFR. (5) Measuring cellphone Specific Absorption Rates (SAR) at arbitrary distances from the head. (6) Averaging SAR doses at volumetric/mass scales irrelevant to health. (7) Using unrealistic simulations for cell phone SAR estimations. Low-cost software and hardware modifications are proposed here for cellular phone RFR exposure mitigation: (1) inhibiting RFR emissions in contact with the body, (2) use of antenna patterns reducing the Percent of Power absorbed in the Head (PPHead) and body and increasing the Percent of Power Radiated for communications (PPR), and (3) automated protocol-based reductions of the number of RFR emissions, their duration, or integrated dose. These inexpensive measures do not fundamentally alter cell phone functions or communications quality. A health threat is scientifically documented at many levels and acknowledged by industries. Yet mitigation of RFR exposures to users does not appear as a priority with most cell phone manufacturers.
... There is evidence from across the globe that electromagnetic emissions may increase the stress levels in the human body and may cause depression [2][3][4] and disturbance in the brain waves [5] , increase the risk of heart diseases [6] in adults, and disturbance in the sleep quality [7] , even affecting the unborn child [8][9] and children [10][11][12] . In fact, the evidence from brain imaging also indicates that EMF from devices like mobile phones can alter the regional cerebral blood flow, sleep, and waking EEG of the participants [13][14][15][16] . ...
Efficacy of Enviroglobe and its impact on sleep quality
... The amount of energy that mobile phone users are exposed to depends on factors such as the type of mobile technology, the distance between the phone and the user, the amount and type of mobile phone use, and the user's distance from the mobile towers [35,36]. ...
Background
With the advancement of technology, the rate of access and use of mobile phones in different communities has increased significantly. Mobile phones emit electromagnetic waves and therefore excessive use of them may have harmful effects on physical and mental health and especially on the cardiovascular system. This study aimed to investigate the association between self-reported mobile phone use duration and blood pressure and heart rate (HR) using data from Ravansar non-communicable diseases (RaNCD) cohort study.
Methods
The present cross-sectional study was performed using the data of 8905 out of 10,065 participants in the RaNCD study in Iran. According to the mean self-reported duration of mobile phone usage (min/day) over the previous 12 months, all users were divided into four groups. The first and fourth groups had the least and most time using mobile phones respectively. The relationship between blood pressure and the duration of mobile phone use was determined using univariate and multiple linear regression.
Results
Of 8905 participants aged 35–65 years, 1515 (17.0%) of them didn't use mobile phones. The minimum, maximum, and mean duration of self-reported mobile phone use between users were 3.4, 50.4, and 19.5 min/day, respectively. A decrease in women's systolic and diastolic blood pressure (SBP and DBP) and HR was observed by increasing the duration of mobile phone use. With adjustment for effective confounding factors, there was a significant negative association between SBP [-2.52 (-4.11, -0.94)], DBP [-1.86 (-2.83, -0.89)], and duration of mobile use.
Conclusion
In this study, a significant decreasing trend was found between SBP, DBP, and HR and higher mobile phone usage in women. Based on regression analysis, SBP, DBP, and duration of mobile phone use were associated negatively in those who used their phones for at least 8 h.
... Additionally, although glioblastoma may be less common in Asian and African countries possibly due to differences in age distribution and diagnostic accessibility (1), the age-adjusted incidence rate of glioblastoma has recently increased in North American and European countries (5,6). The improvement in diagnostic techniques, lifestyle changes, or environmental factors might be responsible for the increased incidence rate of glioblastoma, leading the increased chance of ENM (7,8). Therefore, clinician should be aware of the possibility of ENM in glioblastoma and its risk factors to prevent oversight and misdiagnosis. ...
Background
Extraneural metastasis (ENM) of glioblastoma are rare. However, as patient overall survival improves, the incidence of ENM has gradually increased. Although several risk factors have been proposed, venous sinus invasion was regarded as a very exceptional route for ENM.
Case description
We report a 60-year-old man with glioblastoma in the temporal lobe, invading the transverse and sigmoid venous sinus. After gross total tumor resection, the patient received the standard chemoradiation therapy. Systemic evaluation for persistent shoulder and back pain revealed widespread metastasis to lymph nodes and multiple bones 9 months after surgery. Despite spine radiation therapy, the patient became paraplegic and died 1 year after surgery.
Conclusions
Venous sinus invasion should be kept in mind by physicians, as a risk factor for glioblastoma ENM. Systemic evaluation of these patients with extracranial symptoms should be performed without hesitation.
... The mathematical derivations of nanoparticle-aided laser-induced interstitial thermotherapy on tumour tissue and cancer therapies were constructed using the same model by Xu et al. [27]. Other models have investigated the thermal wave models of bioheat transfer by applying them to the brain [1,[28][29][30][31][32][33]. Youssef et al. [34] looked at how heat waves radiated by cellular devices affected a multi-layer human skull. ...
In this study, a mathematical model of a human head with three layers of skin, bone, and brain for both children and adults was created. The phase-lag time definition was used to evaluate the internal thermal reaction that is created via the human head as a result of chemical processes. In the framework of the two-temperature heat conduction model, the governing equations were developed. The inversions were numerically derived using an approximation approach after applying Laplace transforms. When the human head is exposed to cellular devices that emit an electromagnetic wave, the dynamic and conductive temperature increments distributions have been calculated and discussed with various values of the two-temperature parameter, time, relaxation time, power transmission frequency, and power density. Each layer of the human cranium is affected by all of the characteristics analysed. The impacts of electromagnetic waves emitted by cellular devices were more detrimental to the bones of children’s heads than they are to the bones of adults’ heads.
... In particular, a large body of research has investigated the possible effects of exposure to RF fields used by mobile phones (300-3000 MHz) on the human central nervous system (CNS) (for reviews see [1][2][3]). Although evidence exists pointing to an effect of RF fields on brain oscillations [4][5][6][7] (reviewed in [8]), evoked potentials [9,10] (but see [11]), and glucose metabolism [12], such changes have not been claimed as having any adverse health effects [13,14]. Interaction between RF fields and biological systems are best understood from a thermal perspective [15,16]. ...
Previous studies have shown that spontaneously active cultured networks of cortical neuron grown planar microelectrode arrays are sensitive to radiofrequency (RF) fields and exhibit an inhibitory response more pronounced as the exposure time and power increase. To better understand the mechanism behind the observed effects, we aimed at identifying similarities and differences between the inhibitory effect of RF fields (continuous wave, 1800 MHz) to the γ-aminobutyric acid type A (GABAA) receptor agonist muscimol (MU). Inhibition of the network bursting activity in response to RF exposure became apparent at an SAR level of 28.6 W/kg and co-occurred with an elevation of the culture medium temperature of ~1°C. Exposure to RF fields preferentially inhibits bursting over spiking activity and exerts fewer constraints on neural network bursting synchrony, differentiating it from a pharmacological inhibition with MU. Network rebound excitation, a phenomenon relying on the intrinsic properties of cortical neurons, was observed following the removal of tonic hyperpolarization after washout of MU but not in response to cessation of RF exposure. This implies that hyperpolarization is not the main driving force mediating the inhibitory effects of RF fields. At the level of single neurons, network inhibition induced by MU and RF fields occurred with reduced action potential (AP) half-width. As changes in AP waveform strongly influence efficacy of synaptic transmission, the narrowing effect on AP seen under RF exposure might contribute to reducing network bursting activity. By pointing only to a partial overlap between the inhibitory hallmarks of these two forms of inhibition, our data suggest that the inhibitory mechanisms of the action of RF fields differ from the ones mediated by the activation of GABAA receptors.
... Results of the present study demonstrated that MWR mediated oxidative stress in rats was associated with metabolic and morphological aberrations in the brain. The results were in support of the previously done in vivo studies (Volkow et al., 2011;Zymantiene et al., 2020) suggested that the chronic exposure of MWR exerts neuronal damage. Lipid imbalances in the central nervous system may cause functional changes, which can lead to disorders like Alzheimer's, Huntington's, and Parkinson's (Adibhatla and J.F.H., 2007). ...
Present study exhibited the oxidative potential of microwave radiation (MWR) leading to the neurodegeneration in rats. Wistar rats were exposed at 2100MHz frequency for 4hours/day, 5days/week/3 months. Animals were exposed at an estimated specific absorption rate (0.453W/kg) and power density (8.237µW/m2). After exposure irradiated group was compared with control group. Results indicated that microwave exposure significantly increased the levels of serological triglycerides and cholesterol. Oxidative stress is observed through alteration of Glutathione homeostasis followed by Activated inflammatory response further confirmed by pro and anti-inflammatory cytokines in the exposed group. Histopathological assessments and electron microscopic observation confirmed a significant change in the myelination pattern and cellular organelles in the brain of exposed animals. Taking everything into account it can be concluded that chronic exposure of 2100-MHz frequency caused oxidative stress, which leads to neural damage and demyelination and may affect neural communication.
... Overuse of mobile has been reported as a risk factor for user's health problems. Volkow and colleagues reported that a prolonged use (≥50 min) of mobile phone increased level of glucose metabolism in brain tissues (Volkow et al., 2011). ...
Hypertension is a cause of cardiovascular complications and premature death worldwide. Prevalence of hypertension is doubled older population. Close monitoring must be promptly equipped by healthcare team without delays to preserve intact cardiovascular system. In Thailand, village health volunteers (VHVs, OSOMO in Thai) are key healthcare personnel that coordinate health information between the older persons and health care professionals. The VHVs have been trained to measure blood pressure, record, and submit a report to health professionals in monthly basis. However, the blood pressure records in some health areas were still incomplete due to incontiguous data collection and difficult access to the older persons. This project was aimed to develop a geographical information system (GIS)-based mobile application for hypertension surveillance and monitoring in older persons in rural community by the VHVs using the analysis, design, development, implementation, and evaluation (ADDIE) model. Results showed that blood pressure data of 6,421 (76.92%) of the older persons were recorded. We employed the Google Map Application Programming Interface (API) to identify 5788 latitude and longitude of the older persons' living locations. Other health data were also recorded. The mobile application called "OSOMO prompt" for both iPhone (iOS) and Android systems containing health knowledge repository on hypertension will be distributed to 1,125 VHVs in 8 districts. In summary, this mobile application will be useful as a tool for surveillance and self-monitoring of hypertension in older persons in rural community.
Background
Concerns regarding potential negative impacts on human health are growing as cell phone use dramatically expands worldwide. Due to the anatomical position of the brain, cell phones emit nonionizing radiofrequency waves that may have an impact on it.
Objectives
The study aims to examine the effect of mobile phone radiation in male rats on the histological structure, and sonographic imaging of the brain of rats after mobile phone radiation exposure and investigate the ameliorating role of moringa.
Materials and Methods
In the study, 44 male Albino rats were used. The rats were randomly divided into six groups and exposed to cell phone radiation (in the data or calling modes) for 10 weeks. The 200 mg/kg of body weight of moringa extract was administered to evaluate the protective role of the rats for 10 weeks.
Results
A sonographic and histological analysis of the rat brain showed that rats exposed to mobile phone radiation suffered serious damage to their neurons in several parts of the brain. Meanwhile, the rats given moringa extract suffered less harm.
Conclusion
Rats given moringa extract had less damage to neuronal architecture in their brains.
Are there at least some ‘tin-foil hat guys’ who aren’t crazy? In simple terms this paper seeks to analyse the credibility of the primary argument: If multiple defense and intelligence officials claim, often to their discredit, that: i) they have been neurologically assaulted by microwaves; ii) Neuroweapons have been researched and developed for over 60 years iii) non-human intelligence currently interact with humans and utilise advanced
regarding several former premises; then in applying the principle of charity, why should we not consider the possibility that at least some civilians may actually be affected by such
technology on earth; iv) there is a significant government-led disinformation campaign Electromagnetic
phenomena? The primary aim of this paper was to epistemologically examine the possibility Theory. for claims of neurowarfare or electronic harassment to be veridical within a proportion of individuals self-describing as a Targeted Individual (TI) or as having Havana Syndrome (HS).
The secondary aim was to address gaps in the literature and ongoing medicolegal discourse which have, thus far, not been contended with within analytical philosophy. It was found that HS and TI claims did not meet the full criteria for an Unwarranted Conspiracy Theory (UCT) and can be regarded as a progressive Research Program (RP). While, prima facie, appearing as an epistemological black hole, some claims were found inductively to have a legitimate basis for concern. Therefore, stigmatising preconceptions may act as an epistemic harm to well- meaning but misinformed practitioners in the process of diagnosis. The primary issue that was then dealt with is how clinicians may demarcate the presence of a disorder given that substantiated justification remains empirically undefined. In conclusion, the paper found clinicians ought to adopt consideration to a wider array of individual and socio-political contextual factors in the process of evaluating the coherency of self-reporting TI belief systems. Furthermore, in defining the complex etiology encountered, correlation with Electromagnetic Hypersensitivity (EHS), Anomalous Health Incidents (AHI), Radio Frequency (RF) exposure, Non-Human Intelligence (NHI) interactions and Exceptional Experiences (EE) should all be considered in the formation of explanatory hypotheses.
bold xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Objective
: In our wireless-centric world, evaluating the health effects of radio frequency electromagnetic radiation (RF-EMR) is crucial. An existing research gap pertains to the replication of real-world specific absorption rates (SAR) for RF-EMR, especially within aquatic environments. We aimed to bridge this gap using an innovative TEM cell platform to replicate realistic SAR conditions in water and assess RF-EMR's impact on neuroanatomical and behavioral changes.
Results
: We examined RF-EMR effects on zebrafish embryos exposed to RF-EMR during the 4-58 hours post-fertilization phase. Temporary neuroanatomical enlargements and minor behavioral shifts were observed, diminishing by day 8 post-fertilization.
Conclusion
: Short-term RF-EMR exposure at tested levels did not yield significant long-term effects. Nevertheless, investigating prolonged exposure remains imperative. Our study serves as a pioneering model for future investigations into the biological consequences of RF-EMR exposure, highlighting the importance of assessing its health implications in our wireless-centric world.
This article provides a comprehensive analysis of the biological hazards associated with electromagnetic radiation (EMR) using mobile phones as a case study, aiming to dispel ambiguities and provide practical insights grounded in scientific evidence. Delving into the intricate interplay between EMR and living organisms, the authors explore various biological effects, including DNA damage, oxidative stress, and neurological impacts, substantiated by a wealth of research studies. The conflicting findings and controversies in EMR research are critically examined, shedding light on methodological differences, confounding variables, and ethical considerations. Regulatory guidelines, safety standards, and precautionary approaches are evaluated, emphasizing the need for international collaboration and continued research. Furthermore, the article clearly describes mitigation strategies at individual, community, and policy levels, empowering readers with practical measures to minimize EMR exposure while maximizing the benefits of modern technology.
Objectives
There is a paucity of systematic studies conducted to get information on the impact of mobile phone radiation on health. This pilot study was done to explore the use of mobile phones in patients with stroke.
Methods
This cross-sectional study used a structured questionnaire among stroke patients in a tertiary hospital in India. We collected demographic details, history, and information on their mobile phone type, usage, and specific absorption rate (SAR) value. We used descriptive statistics to report our findings.
Results
This group of 50 stroke patients was predominantly an urban population (78%) with a higher number of male subjects (56%); a higher prevalence of ischemic stroke (76%); 30% were smokers; with comorbidities of hypertension (75%) and diabetes (46%), a significant proportion of whom were not on regular treatment 64% and 74%, respectively. More number of patients used feature phones (82%). The median (SAR) value of all phones was 0.81 W/kg. Hypertension was present in patients who had contact with the phone for >5 hours (78%), subjects who kept their phone closer to the pillow while sleeping (71%), and those carrying a phone in their pockets or on self for >5 hours (80%).
Conclusion
This group of patients had predominantly ischemic stroke; a significant proportion having hypertension and diabetes were not on regular treatment and were smokers. Cases of hypertension were noted to be higher in patients with increased exposure to mobile phone radiation. As a pilot study with limitations of a small number of patients, these findings could be only incidental. Further research is required to make any conclusions.
Efforts to increase the quality of this environment have been going on since the beginning of the concern for shelter in the history of humanity. The main targets of the user, designers, practitioners, and decision-makers are to carry the quality of life, health, safety, and welfare of individuals and other living things to the next level. Problems have been identified to increase the function and quality of the space, spatial requirements have been determined, and researched, and some design factors have been determined to reach the most appropriate solution. The researchers focused on the proposition that the effectiveness of these factors before and during the design process would increase the quality of the space. However, since research generally focuses on indoor quality, the outdoor quality factors that are part of urban design are not clear. This work, was designed to evaluate the usability of these factors, which were determined and measured especially to deal with the interior, in designs at larger scales (street, neighborhood, city…) and to improve the existing. In designs outside the spatial scale, where almost all factors can be controlled by the relevant stakeholders of the process, the subject is approached through changeable and unchangeable parameters and their balancing. Studies on the factors determined during the process were compiled and their effects on different scales were evaluated as a result of these compilations. As a result of the evaluation, some suggestions were given. In the process of redesigning the space, selecting feasible suggestions, and incorporating them into the creation of the future physical space, using the suggestions as urban rehabilitation tools, and considering these interventions to be flexible and suitable for various factors are of great importance for the psychology of the users.
It is well-documented that radiofrequency electromagnetic radiation (RF-EMR) from the cell phone contributes to testicular dysfunction and subsequently predisposes individuals, especially male to infertility. Panax ginseng (P. ginseng) exerts antioxidant, antidiabetic, neuroprotective, and anti-inflammatory effects in biological systems. However, its protective role against reproductive dysfunction, including testiculopathy is unclear. The objective of this study was to examine the protective effects of P. ginseng extract on testicular damage induced by RF-EMR from cell phones in male Wistar rats.
Twenty adult male Wistar rats (120–150 g) were randomly divided into four groups of n = 5; Control group received vehicle (normal saline, po), P. ginseng group received 200 mg/kg of P. ginseng extract (po), RF-EMR group was exposed to 900MHz of radiation and RF-EMR + P. ginseng group was exposed to 900MHz of radiation and was concomitantly treated with 200 mg/kg of P. ginseng (po). The treatment was done daily for 56 days. The animals were sacrificed, and the biochemical/endocrine parameters and the histology of testes were evaluated.
There was a significant decrease in spermatogonia, sperm count, sperm motility, and sperm morphology with decrease in progressivity in RF-EMR group compared with control. Likewise, a significant decrease was observed in serum-luteinizing hormone, testosterone and glutathione peroxidase with degeneration of germ cells and Leydig cells, and a distorted interstitium in RF-EMR group compared with control. However, the administration of P. ginseng attenuated these alterations.
The results of the present study suggest that supplementation with P. ginseng extract ameliorates testicular dysfunction associated with RF-EMR from cell phone by enhancement of antioxidant capacity.
5G, the fifth generation of RF (Radio Frequency) radiation, is on the verge of being implemented globally. Current communication systems/technology use electromagnetic field (EMF) in the range of Megahertz but the 5G will have EMFs in the GHz (Gigahertz) range. It is targeted to deliver huge network capacity, higher reliability, improved efficiency, extremely low latency, very high multi Gbps (Giga bytes per second) peak data speeds and a consistent higher performance user experience to more and more users. A lot is known about hazards from the 3G and 4G electromagnetic fields that are in use currently for cell phones and Wi-Fi (Wireless Fidelity) but very little is known about the 5G hazards and effects. A need to investigate its potential risks to the environment and human health is essential. In this paper we have tried to assimilate both the benefits and concerns of this new technology.
Low-frequency non-ionizing Electromagnetic Radiation (EMR) emanates from antennas in Mobile Base Stations (MBS). There is a general concern that living close to a Mobile Base Station (MBS) could be associated with health effects such as headache, sleep disorder, and fatigue. Using a High-Frequency Spectrum Analyzer (HF-2025E) coupled with its hyper-log antenna (HL-7025) and a set of questionnaires, this work assessed radiated power on human body surface from eleven (11) MBSs located in Lafia, Nasarawa State, and knowledge of residents on EMR from MBSs. The result shows that mobile operators’ frequencies in the 900MHz band were found to be dominant. The minimum power density was 0.02 μWm ⁻² and the maximum power density was 927.97 μWm ⁻² in the 900 MHz bands. The maximum average absorbed radiated power was 297.77 μW on an adult male body surface area. These maximum values are below the ICNIRP standard of 4.5 Wm ⁻² ; concerns however, are on prolonged exposure whose value may exceed the ICNIRP limit. Results from the questionnaire show an average level (53% and 51%) of awareness of EMR from respondents living close to the MBSs and their safety issues. This paper recommends more public awareness of issues relating to EMR from MBSs.
DETERMINATION OF THE ACTUAL INTENSITY BY CORRECTION OF THE EMISSION SPECTRUM LINES OF HEAVY METALS CONTAINED IN CRUDE OIL USING LASER INDUCED PLASMA –TECHNIQUE
Kétrészes narratív összefoglalónkban áttekintést nyújtunk az elektromágneses tereknek tulajdonított idiopátiás környezeti intoleranciával (IEI-EMF, más néven elektromágneses túlérzékenységgel) kapcsolatos tudományos eredményekről, a kutatások jelenlegi állásáról. Az elektromágneses túlérzékenység olyan állapotot jelent, amely során az érintett személy tüneteket tapasztal az elektromos eszközök közelében vagy azok használatakor, és tüneteit az elektromágneses expozíciónak tulajdonítja. Az Egészségügyi Világszervezet jelenlegi álláspontja szerint az IEI-EMF nem diagnosztikus kategória, megállapításához jelenleg sem orvosi teszt, sem valid protokoll nem áll rendelkezésre. Jellemző az állapotra a nagyfokú distressz, gyakran vezet szociális izolációhoz, valamint a munkaképesség elvesztéséhez. Gyakoriak a különböző komorbid mentális zavarok, mint a szorongás, depresszió, szomatizáció. Az elektromágneses túlérzékenység etiológiájával kapcsolatos elméletek két fő irányvonalat képviselnek: míg a biofizikai megközelítés szerint a tüneteket elektromágneses mezők által aktivált fiziológiai folyamatok idézik elő, addig a pszichogén elméletet propagáló szerzők a tünetképzés jelenségét pszichológiai folyamatokkal magyarázzák (például torzult figyelmi és attribúciós folyamatok, nocebohatás, asszociatív tanulás). Számos kutató hangsúlyozza azonban, hogy a jelenség teljes megértéséhez a két megközelítés integrálására és interdiszciplináris kutatócsoportok felállítására van szükség. Jelen írásunkban a jelenséggel kapcsolatos jellemzőket kutatói és orvosi szemszögből járjuk körül: az etiológiával kapcsolatos elméletek bemutatásán túl kitérünk a vizsgálati, módszertani nehézségekre, a definíciós és diagnosztikus problémákra és a terápiás lehetőségekre.
An increasing number of life science students are taking physics courses in college as more physics-based medical technologies are being implemented in hospitals and clinics. Most of these students are unable to appreciate the connection between physics and their fields when taking a typical physics course. One of the best ways to bridge physics with another area of study is to involve students in a small but exciting research project such as relating the physics of microwaves to biological organisms. A cell phone was used to study the effect of its emitted microwaves on the growth of tomato plants after exposing the seeds to the signal during germination.
Objectives
Excessive mobile phone use contributes to distracted driving, may increase risk for automobile accidents, and a minority of mobile phone users exhibit behaviors consistent with technological addiction. The purpose of this study was to determine whether cell phone beliefs and behaviors could be changed by a brief educational encounter. The Theory of Reasoned Action provided a lens for viewing attitudes and behavior.
Methods
A one-week pre-post design with a thirty-day follow-up was used with participants (N = 215, 67.0% female, age = 20.0 + 1.6) assigned to a peer-led intervention or comparison group. The intervention included cell phone educational materials regarding the potential for negative health effects of mobile phone use. A short index of cell phone behavior was developed which showed good internal consistency with a Cronbach’s α of .81.
Results
The intervention group “agreed” or “strongly-agreed” more than the comparison group on five of the seven areas of cell phone beliefs and behaviors ( P < 0.05, item Cohen’s d = .32 to .47, total d = .50) at one week following receipt of educational materials.
Conclusions
We conclude that attitudes and behaviors regarding mobile phones are malleable and susceptible to change in young adults following a brief psychoeducational intervention.
Much of the controversy over the cause of electrohypersensitivity (EHS) lies in the absence of recognized clinical and biological criteria for a widely accepted diagnosis. However, there are presently sufficient data for EHS to be acknowledged as a distinctly well-defined and objectively characterized neurologic pathological disorder. Because we have shown that 1) EHS is frequently associated with multiple chemical sensitivity (MCS) in EHS patients, and 2) that both individualized disorders share a common pathophysiological mechanism for symptom occurrence; it appears that EHS and MCS can be identified as a unique neurologic syndrome, regardless its causal origin. In this overview we distinguish the etiology of EHS itself from the environmental causes that trigger pathophysiological changes and clinical symptoms after EHS has occurred. Contrary to present scientifically unfounded claims, we indubitably refute the hypothesis of a nocebo effect to explain the genesis of EHS and its presentation. We as well refute the erroneous concept that EHS could be reduced to a vague and unproven “functional impairment”. To the contrary, we show here there are objective pathophysiological changes and health effects induced by electromagnetic field (EMF) exposure in EHS patients and most of all in healthy subjects, meaning that excessive non-thermal anthropogenic EMFs are strongly noxious for health. In this overview and medical assessment we focus on the effects of extremely low frequencies, wireless communications radiofrequencies and microwaves EMF. We discuss how to better define and characterize EHS. Taken into consideration the WHO proposed causality criteria, we show that EHS is in fact causally associated with increased exposure to man-made EMF, and in some cases to marketed environmental chemicals. We therefore appeal to all governments and international health institutions, particularly the WHO, to urgently consider the growing EHS-associated pandemic plague, and to acknowledge EHS as a new real EMF causally-related pathology.
Previous studies have shown that spontaneously active cultured networks of cortical neuron grown planar microelectrode arrays are sensitive to radiofrequency (RF) fields and exhibit an inhibitory response more pronounced as the exposure time and power increase. To better un-derstand the mechanism behind the observed effects, we aimed at identifying similarities and differences between the inhibitory effect of RF fields (continuous wave, 1800 MHz) to the γ-aminobutyric acid type A (GABAA) receptor agonist muscimol (MU). Inhibition of the network bursting activity in response to RF exposure became apparent at an SAR level of 28.6 W/kg and co-occurred with an elevation of the culture medium temperature of ~1[degree]C. Expo-sure to RF fields preferentially inhibits bursting over spiking activity and exerts fewer constraints on neural network bursting synchrony, differentiating it from a pharmacological inhibition with MU. Network rebound excitation, a phenomenon relying on the intrinsic properties of cortical neurons, was observed following the removal of tonic hyperpolarization after washout of MU but not in response to cessation of RF exposure. This implies that hyperpolarization is not the main driving force mediating the inhibitory effects of RF fields. At the level of single neurons, network inhibition induced by MU and RF fields occurred with reduced action potential (AP) half-width. As changes in AP waveform strongly influence efficacy of synaptic transmission, the narrowing effect on AP seen under RF exposure might contribute to reducing network bursting activity. By pointing only to a partial overlap between the inhibitory hallmarks of these two forms of inhibition, our data suggest that the inhibitory mechanisms of the action of RF fields differ from the ones mediated by the activation of GABAA receptors.
Ocular infection is a world wide issue especially for public health field which could be a result to its own normal flora due to subjection to external factors (e.g. stress, getting older, hits, surgical operations, systemic diseases and losing commensal flora). Ocular pathogens could be healed by a group of topical antibiotics, but with time, drug resistance had been developed, which more magnified by wrong diagnosis and random use of antibiotics leading to unexpected complications e.g. visual problems, leading to blindness at last . Alternative therapy had been used to treat such infections including plant extracts like Green Tea (Camellia sinensis) . Eye swabs about (50) samples were gathered from people had ocular infections,then biochemical tests diagnosed (30) bacterial isolates. There were (17) isolates (6 isolates of Staphylococcus spp. and 11 isolates were Enterococcus) out of the (30) isolates showed multiple antibiotic resistance to nine antibiotics by disc-diffusion method,there were high complete resistance to Moxifloxacin and Bacitracin, in contrast to Ciprofloxacin and Chloramphenicol. The antibacterial effects of hot water, cold water,Acetone, Ethanol and Methanol Green tea extracts was examined against the (17) multiple antibiotic resistant isolates by agar-well diffusion method using. Only the Ethanol and Methanol green tea extract showed promising results, without any effect of the remaining green tea extracts. Green tea extracts were equal to Ciprofloxacin and Sulphamethoxazole in effectiveness against antibiotic resistant isolates . The (17) isolates were tested for production of biofilm and protease. (12) isolates were biofilm-producer but after subjection to Ethanol Green tea extract changed into non biofilmformer. (13) isolate were protease-producer but after subjection to Ethanol Green tea extract changed into non protease-former. Key words: Eye Swabs, Antibiotic Resistance, Alternative Therapy, Green Tea Extracts, Biofilm and Protease.
Aerobic glycolysis is defined as glucose utilization in excess of that used for oxidative phosphorylation despite sufficient oxygen to completely metabolize glucose to carbon dioxide and water. Aerobic glycolysis is present in the normal human brain at rest and increases locally during increased neuronal activity; yet its many biological functions have received scant attention because of a prevailing energy-centric focus on the role of glucose as substrate for oxidative phosphorylation. As an initial step in redressing this neglect, we measured the regional distribution of aerobic glycolysis with positron emission tomography in 33 neurologically normal young adults at rest. We show that the distribution of aerobic glycolysis in the brain is differentially present in previously well-described functional areas. In particular, aerobic glycolysis is significantly elevated in medial and lateral parietal and prefrontal cortices. In contrast, the cerebellum and medial temporal lobes have levels of aerobic glycolysis significantly below the brain mean. The levels of aerobic glycolysis are not strictly related to the levels of brain energy metabolism. For example, sensory cortices exhibit high metabolic rates for glucose and oxygen consumption but low rates of aerobic glycolysis. These striking regional variations in aerobic glycolysis in the normal human brain provide an opportunity to explore how brain systems differentially use the diverse cell biology of glucose in support of their functional specializations in health and disease.
Intensive implementation of mobile telephony technology in everyday human life during last two decades has given a possibility for epidemiological estimation of long-term effects of chronic exposure of human organism to low-intensive microwave (MW) radiation. Latest epidemiological data reveal a significant increase in risk of development of some types of tumors in chronic (over 10 years) users of mobile phone. It was detected a significant increase in incidence of brain tumors (glioma, acoustic neuroma, meningioma), parotid gland tumor, seminoma in long-term users of mobile phone, especially in cases of ipsilateral use (case-control odds ratios from 1.3 up to 6.1). Two epidemiological studies have indicated a significant increase of cancer incidence in people living close to the mobile telephony base station as compared with the population from distant area. These data raise a question of adequacy of modern safety limits of electromagnetic radiation (EMR) exposure for humans. For today the limits were based solely on the conception of thermal mechanism of biological effects of RF/MW radiation. Meantime the latest experimental data indicate the significant metabolic changes in living cell under the low-intensive (non-thermal) EMR exposure. Among reproducible biological effects of low-intensive MWs are reactive oxygen species overproduction, heat shock proteins expression, DNA damages, apoptosis. The lack of generally accepted mechanism of biological effects of low-intensive non-ionizing radiation doesn't permit to disregard the obvious epidemiological and experimental data of its biological activity. Practical steps must be done for reasonable limitation of excessive EMR exposure, along with the implementation of new safety limits of mobile telephony devices radiation, and new technological decisions, which would take out the source of radiation from human brain.
The use of cellular telephones has grown explosively during the past two decades, and there are now more than 279 million wireless subscribers in the United States. If cellular phone use causes brain cancer, as some suggest, the potential public health implications could be considerable. One might expect the effects of such a prevalent exposure to be reflected in general population incidence rates, unless the induction period is very long or confined to very long-term users. To address this issue, we examined temporal trends in brain cancer incidence rates in the United States, using data collected by the Surveillance, Epidemiology, and End Results (SEER) Program. Log-linear models were used to estimate the annual percent change in rates among whites. With the exception of the 20-29-year age group, the trends for 1992-2006 were downward or flat. Among those aged 20-29 years, there was a statistically significant increasing trend between 1992 and 2006 among females but not among males. The recent trend in 20-29-year-old women was driven by a rising incidence of frontal lobe cancers. No increases were apparent for temporal or parietal lobe cancers, or cancers of the cerebellum, which involve the parts of the brain that would be more highly exposed to radiofrequency radiation from cellular phones. Frontal lobe cancer rates also rose among 20-29-year-old males, but the increase began earlier than among females and before cell phone use was highly prevalent. Overall, these incidence data do not provide support to the view that cellular phone use causes brain cancer.
The effects of exposure to radiofrequency electromagnetic fields (EMF), specifically related to the use of mobile telephones, on the nervous system in humans have been the subject of a large number of experimental studies in recent years. There is some evidence of an effect of exposure to a Global System for Mobile Telecommunication (GSM)-type signal on the spontaneous electroencephalogram (EEG). This is not corroborated, however, by the results from studies on evoked potentials. Although there is some evidence emerging that there may be an effect of exposure to a GSM-type signal on sleep EEG, results are still variable. In summary, exposure to a GSM-type signal may result in minor effects on brain activity, but such changes have never been found to relate to any adverse health effects. No consistent significant effects on cognitive performance in adults have been observed. If anything, any effect is small and exposure seems to improve performance. Effects in children did not differ from those in healthy adults. Studies on auditory and vestibular function are more unequivocal: neither hearing nor the sense of balance is influenced by short-term exposure to mobile phone signals. Subjective symptoms over a wide range, including headaches and migraine, fatigue, and skin itch, have been attributed to various radiofrequency sources both at home and at work. However, in provocation studies a causal relation between EMF exposure and symptoms has never been demonstrated. There are clear indications, however, that psychological factors such as the conscious expectation of effect may play an important role in this condition.
Case-control studies have reported inconsistent findings regarding the association between mobile phone use and tumor risk. We investigated these associations using a meta-analysis.
We searched MEDLINE (PubMed), EMBASE, and the Cochrane Library in August 2008. Two evaluators independently reviewed and selected articles based on predetermined selection criteria.
Of 465 articles meeting our initial criteria, 23 case-control studies, which involved 37,916 participants (12,344 patient cases and 25,572 controls), were included in the final analyses. Compared with never or rarely having used a mobile phone, the odds ratio for overall use was 0.98 for malignant and benign tumors (95% CI, 0.89 to 1.07) in a random-effects meta-analysis of all 23 studies. However, a significant positive association (harmful effect) was observed in a random-effects meta-analysis of eight studies using blinding, whereas a significant negative association (protective effect) was observed in a fixed-effects meta-analysis of 15 studies not using blinding. Mobile phone use of 10 years or longer was associated with a risk of tumors in 13 studies reporting this association (odds ratio = 1.18; 95% CI, 1.04 to 1.34). Further, these findings were also observed in the subgroup analyses by methodologic quality of study. Blinding and methodologic quality of study were strongly associated with the research group.
The current study found that there is possible evidence linking mobile phone use to an increased risk of tumors from a meta-analysis of low-biased case-control studies. Prospective cohort studies providing a higher level of evidence are needed.
The Hardell-group conducted during 1997-2003 two case control studies on brain tumours including assessment of use of mobile phones and cordless phones. The questionnaire was answered by 905 (90%) cases with malignant brain tumours, 1,254 (88%) cases with benign tumours and 2,162 (89%) population-based controls. Cases were reported from the Swedish Cancer Registries. Anatomical area in the brain for the tumour was assessed and related to side of the head used for both types of wireless phones. In the current analysis we defined ipsilateral use (same side as the tumour) as >or=50% of the use and contralateral use (opposite side) as <50% of the calling time. We report now further results for use of mobile and cordless phones. Regarding astrocytoma we found highest risk for ipsilateral mobile phone use in the >10 year latency group, OR=3.3, 95% CI=2.0-5.4 and for cordless phone use OR=5.0, 95% CI=2.3-11. In total, the risk was highest for cases with first use <20 years age, for mobile phone OR=5.2, 95% CI=2.2-12 and for cordless phone OR=4.4, 95% CI=1.9-10. For acoustic neuroma, the highest OR was found for ipsilateral use and >10 year latency, for mobile phone OR=3.0, 95% CI=1.4-6.2 and cordless phone OR=2.3, 95% CI=0.6-8.8. Overall highest OR for mobile phone use was found in subjects with first use at age <20 years, OR=5.0, 95% CI 1.5-16 whereas no association was found for cordless phone in that group, but based on only one exposed case. The annual age-adjusted incidence of astrocytoma for the age group >19 years increased significantly by +2.16%, 95% CI +0.25 to +4.10 during 2000-2007 in Sweden in spite of seemingly underreporting of cases to the Swedish Cancer Registry. A decreasing incidence was found for acoustic neuroma during the same period. However, the medical diagnosis and treatment of this tumour type has changed during recent years and underreporting from a single center would have a large impact for such a rare tumour.
Whether low-intensity non-thermal microwave radiation alters the integrity of the blood-brain barrier has been debated since the late 1970s, yet no experimental study has been carried out on humans. The aim of this study was to test, using peripheral markers, whether exposure to a mobile phone-like signal alters the integrity of the human blood-brain and blood-cerebrospinal fluid barriers. A provocation study was carried out that exposed 41 volunteers to a 30 min GSM 890 MHz signal with an average specific energy absorption rate distribution of 1.0 W/kg in the temporal area of the head as measured over any 1g of contiguous tissue. The outcome was assessed by changes in serum concentrations of two putative markers of brain barrier integrity, S100B and transthyretin. Repeated blood sampling before and after the provocation showed no statistically significant increase in the serum levels of S100B, while for transthyretin a statistically significant increase was seen in the final blood sample 60 min after the end of the provocation as compared to the prior sample taken immediately after provocation (p=0.02). The clinical significance of this finding, if any, is unknown. Further randomized studies with use of additional more brain specific markers are needed.
Haemodynamic signals underlying functional brain imaging (for example, functional magnetic resonance imaging (fMRI)) are assumed to reflect metabolic demand generated by local neuronal activity, with equal increases in haemodynamic signal implying equal increases in the underlying neuronal activity. Few studies have compared neuronal and haemodynamic signals in alert animals to test for this assumed correspondence. Here we present evidence that brings this assumption into question. Using a dual-wavelength optical imaging technique that independently measures cerebral blood volume and oxygenation, continuously, in alert behaving monkeys, we find two distinct components to the haemodynamic signal in the alert animals' primary visual cortex (V1). One component is reliably predictable from neuronal responses generated by visual input. The other component-of almost comparable strength-is a hitherto unknown signal that entrains to task structure independently of visual input or of standard neural predictors of haemodynamics. This latter component shows predictive timing, with increases of cerebral blood volume in anticipation of trial onsets even in darkness. This trial-locked haemodynamic signal could be due to an accompanying V1 arterial pumping mechanism, closely matched in time, with peaks of arterial dilation entrained to predicted trial onsets. These findings (tested in two animals) challenge the current understanding of the link between brain haemodynamics and local neuronal activity. They also suggest the existence of a novel preparatory mechanism in the brain that brings additional arterial blood to cortex in anticipation of expected tasks.
The present study addresses the relationship between blood flow and glucose consumption in rat primary somatosensory cortex (SI) in vivo. We examined bilateral neuronal and hemodynamic changes and 2-deoxyglucose (2DG) uptake, as measured by autoradiography, in response to unilateral forepaw stimulation. In contrast to the contralateral forepaw area, where neuronal activity, blood oxygenation/flow and 2DG uptake increased in unison, we observed, in the ipsilateral SI, a blood oxygenation/flow decrease and arteriolar vasoconstriction in the presence of increased 2DG uptake. Laminar electrophysiological recordings revealed an increase in ipsilateral spiking consistent with the observed increase in 2DG uptake. The vasoconstriction and the decrease in blood flow in the presence of an increase in 2DG uptake in the ipsilateral SI contradict the prominent metabolic hypothesis regarding the regulation of cerebral blood flow, which postulates that the state of neuroglial energy consumption determines the regional blood flow through the production of vasoactive metabolites. We propose that other factors, such as neuronal (and glial) release of messenger molecules, might play a dominant role in the regulation of blood flow in vivo in response to a physiological stimulus.
Brain glucose uptake, oxygen metabolism, and blood flow in humans were measured with positron emission tomography, and a resting-state
molar ratio of oxygen to glucose consumption of 4.1:1 was obtained. Physiological neural activity, however, increased glucose
uptake and blood flow much more (51 and 50 percent, respectively) than oxygen consumption (5 percent) and produced a molar
ratio for the increases of 0.4:1. Transient increases in neural activity cause a tissue uptake of glucose in excess of that
consumed by oxidative metabolism, acutely consume much less energy than previously believed, and regulate local blood flow
for purposes other than oxidative metabolism.
Concern has arisen that the use of hand-held cellular telephones might cause brain tumors. If such a risk does exist, the matter would be of considerable public health importance, given the rapid increase worldwide in the use of these devices.
We examined the use of cellular telephones in a case-control study of intracranial tumors of the nervous system conducted between 1994 and 1998. We enrolled 782 patients through hospitals in Phoenix, Arizona; Boston; and Pittsburgh; 489 had histologically confirmed glioma, 197 had meningioma, and 96 had acoustic neuroma. The 799 controls were patients admitted to the same hospitals as the patients with brain tumors for a variety of nonmalignant conditions.
As compared with never, or very rarely, having used a cellular telephone, the relative risks associated with a cumulative use of a cellular telephone for more than 100 hours were 0.9 for glioma (95 percent confidence interval, 0.5 to 1.6), 0.7 for meningioma (95 percent confidence interval, 0.3 to 1.7), 1.4 for acoustic neuroma (95 percent confidence interval, 0.6 to 3.5), and 1.0 for all types of tumors combined (95 percent confidence interval, 0.6 to 1.5). There was no evidence that the risks were higher among persons who used cellular telephones for 60 or more minutes per day or regularly for five or more years. Tumors did not occur disproportionately often on the side of head on which the telephone was typically used.
These data do not support the hypothesis that the recent use of hand-held cellular telephones causes brain tumors, but they are not sufficient to evaluate the risks among long-term, heavy users and for potentially long induction periods.
Usage of mobile phones is rapidly increasing, but there is limited data on the possible effects of electromagnetic field (EMF) exposure on brain physiology. We investigated the effect of EMF vs. sham control exposure on waking regional cerebral blood flow (rCBF) and on waking and sleep electroencephalogram (EEG) in humans. In Experiment 1, positron emission tomography (PET) scans were taken after unilateral head exposure to 30-min pulse-modulated 900 MHz electromagnetic field (pm-EMF). In Experiment 2, night-time sleep was polysomnographically recorded after EMF exposure. Pulse-modulated EMF exposure increased relative rCBF in the dorsolateral prefrontal cortex ipsilateral to exposure. Also, pm-EMF exposure enhanced EEG power in the alpha frequency range prior to sleep onset and in the spindle frequency range during stage 2 sleep. Exposure to EMF without pulse modulation did not enhance power in the waking or sleep EEG. We previously observed EMF effects on the sleep EEG (A. A. Borbély, R. Huber, T. Graf, B. Fuchs, E. Gallmann and P. Achermann. Neurosci. Lett., 1999, 275: 207-210; R. Huber, T. Graf, K. A. Cote, L. Wittmann, E. Gallmann, D. Matter, J. Schuderer, N. Kuster, A. A. Borbély, and P. Achermann. Neuroreport, 2000, 11: 3321-3325), but the basis for these effects was unknown. The present results show for the first time that (1) pm-EMF alters waking rCBF and (2) pulse modulation of EMF is necessary to induce waking and sleep EEG changes. Pulse-modulated EMF exposure may provide a new, non-invasive method for modifying brain function for experimental, diagnostic and therapeutic purposes.
Mobile phones create a radio-frequency electromagnetic field (EMF) around them when in use, the effects of which on brain physiology in humans are not well known. We studied the effects of a commercial mobile phone on regional cerebral blood flow (rCBF) in healthy humans using positron emission tomography (PET) imaging. Positron emission tomography data was acquired using a double-blind, counterbalanced study design with 12 male subjects performing a computer-controlled verbal working memory task (letter 1-back). Explorative and objective voxel-based statistical analysis revealed that a mobile phone in operation induces a local decrease in rCBF beneath the antenna in the inferior temporal cortex and an increase more distantly in the prefrontal cortex. Our results provide the first evidence, suggesting that the EMF emitted by a commercial mobile phone affects rCBF in humans. These results are consistent with the postulation that EMF induces changes in neuronal activity.
During the last century, mankind has introduced electricity and during the very last decades, the microwaves of the modern communication society have spread a totally new entity--the radiofrequency fields--around the world. How does this affect biology on Earth? The mammalian brain is protected by the blood-brain barrier, which prevents harmful substances from reaching the brain tissue. There is evidence that exposure to electromagnetic fields at non thermal levels disrupts this barrier. In this review, the scientific findings in this field are presented. The result is a complex picture, where some studies show effects on the blood-brain barrier, whereas others do not. Possible mechanisms for the interactions between electromagnetic fields and the living organisms are discussed. Demonstrated effects on the blood-brain barrier, as well as a series of other effects upon biology, have caused societal anxiety. Continued research is needed to come to an understanding of how these possible effects can be neutralized, or at least reduced. Furthermore, it should be kept in mind that proven effects on biology also should have positive potentials, e.g., for medical use.
Background The rapid increase in mobile telephone use has generated concern about possible health risks related to radiofrequency electromagnetic fields from this technology.
Methods An interview-based case–control study with 2708 glioma and 2409 meningioma cases and matched controls was conducted in 13 countries using a common protocol.
Results A reduced odds ratio (OR) related to ever having been a regular mobile phone user was seen for glioma [OR 0.81; 95% confidence interval (CI) 0.70–0.94] and meningioma (OR 0.79; 95% CI 0.68–0.91), possibly reflecting participation bias or other methodological limitations. No elevated OR was observed ≥10 years after first phone use (glioma: OR 0.98; 95% CI 0.76–1.26; meningioma: OR 0.83; 95% CI 0.61–1.14). ORs were <1.0 for all deciles of lifetime number of phone calls and nine deciles of cumulative call time. In the 10th decile of recalled cumulative call time, ≥1640 h, the OR was 1.40 (95% CI 1.03–1.89) for glioma, and 1.15 (95% CI 0.81–1.62) for meningioma; but there are implausible values of reported use in this group. ORs for glioma tended to be greater in the temporal lobe than in other lobes of the brain, but the CIs around the lobe-specific estimates were wide. ORs for glioma tended to be greater in subjects who reported usual phone use on the same side of the head as their tumour than on the opposite side.
Conclusions Overall, no increase in risk of glioma or meningioma was observed with use of mobile phones. There were suggestions of an increased risk of glioma at the highest exposure levels, but biases and error prevent a causal interpretation. The possible effects of long-term heavy use of mobile phones require further investigation.
Statistical parametric maps are spatially extended statistical processes that are used to test hypotheses about regionally specific effects in neuroimaging data. The most established sorts of statistical parametric maps (e.g., Friston et al. [1991]: J Cereb Blood Flow Metab 11:690–699; Worsley et al. [1992]: J Cereb Blood Flow Metab 12:900–918) are based on linear models, for example ANCOVA, correlation coefficients and t tests. In the sense that these examples are all special cases of the general linear model it should be possible to implement them (and many others) within a unified framework. We present here a general approach that accomodates most forms of experimental layout and ensuing analysis (designed experiments with fixed effects for factors, covariates and interaction of factors). This approach brings together two well established bodies of theory (the general linear model and the theory of Gaussian fields) to provide a complete and simple framework for the analysis of imaging data.
The importance of this framework is twofold: (i) Conceptual and mathematical simplicity, in that the same small number of operational equations is used irrespective of the complexity of the experiment or nature of the statistical model and (ii) the generality of the framework provides for great latitude in experimental design and analysis.
The brain is a complex, heterogeneous organ composed of many anatomical and functional components with markedly different
levels of functional activity that vary independently with time and function. Other tissues are generally far more homogeneous,
with most of their cells functioning similarly and synchronously in response to a common stimulus or regulatory influence.
The central nervous system, however, consists of innumerable subunits, each integrated into its own set of functional pathways
and networks, and subserving only one or a few of the many activities in which the nervous system participates. Understanding
how the nervous system functions requires knowledge not only of the mechanisms of excitation and inhibition, but even more
so of their precise localization in the nervous system and the relationships of neural subunits to specific functions.
The debate regarding the health effects of low-intensity electromagnetic radiation from sources such as power lines, base stations, and cell phones has recently been reignited. Wireless communication has dramatically influenced our lifestyle; its impact on human health has not been completely assessed. Widespread concern continues in the community about the deleterious effects of radiofrequency radiations on human tissues and the subsequent potential threat of carcinogenesis. Exposure to low-frequency electromagnetic field has been linked to a variety of adverse health outcomes. This article surveys the results of early cell phone studies, where exposure duration was too short to expect tumor genesis, and 2 sets of more recent studies with longer exposure duration: the Interphone studies and the Swedish studies led by Hardell.
Some concern has arisen about adverse health effects of cell phones, especially the possibility that the low power microwave-frequency signal transmitted by the antennas on handsets might cause brain tumors or accelerate the growth of subclinical tumors. We analyzed data from the Statistical Report: Primary Brain Tumors in the United States, 2000-2004 and 2007 cell phone subscription data from the Governing State and Local Sourcebook. There was a significant correlation between number of cell phone subscriptions and brain tumors in nineteen US states (r = 0.950, P < 0.001). Because increased numbers of both cell phone subscriptions and brain tumors could be due solely to the fact that some states, such as New York, have much larger populations than other states, such as North Dakota, multiple linear regression was performed with number of brain tumors as the dependent variable, cell phone subscriptions, population, mean family income and mean age as independent variables. The effect of cell phone subscriptions was significant (P = 0.017), and independent of the effect of mean family income (P = 0.894), population (P = 0.003) and age (0.499). The very linear relationship between cell phone usage and brain tumor incidence is disturbing and certainly needs further epidemiological evaluation. In the meantime, it would be prudent to limit exposure to all sources of electro-magnetic radiation.
Echo planar imaging (EPI), the gold standard technique for functional MRI (fMRI), is based on fast magnetic field gradient switching. These time-varying magnetic fields induce electric (E) fields in the brain that could influence neuronal activity; but this has not been tested. Here we assessed the effects of EPI on brain glucose metabolism (marker of brain function) using PET and 18F 2-fluoro-2-deoxy-D-glucose ((18)FDG). Fifteen healthy subjects were in a 4 T magnet during the (18)FDG uptake period twice: with (ON) and without (OFF) EPI gradients pulses along the z-axis (G(z): 23 mT/m; 250 mus rise-time; 920 Hz). The E-field from these EPI pulses is non-homogeneous, increasing linearly from the gradient's isocenter (radial and z directions), which allowed us to assess the correlation between local strength of the E-field and the regional metabolic differences between ON and OFF sessions. Metabolic images were normalized to metabolic activity in the plane positioned at the gradient's isocenter where E=0 for both ON and OFF conditions. Statistical parametric analyses used to identify regions that differed between ON versus OFF (p<0.05, corrected) showed that the relative metabolism was lower in areas at the poles of the brain (inferior occipital and frontal and superior parietal cortices) for ON than for OFF, which was also documented with individual region of interest analysis. Moreover the magnitude of the metabolic decrements was significantly correlated with the estimated strength of E (r=0.68, p<0.0001); the stronger the E-field the larger the decreases. However, we did not detect differences between ON versus OFF conditions on mood ratings nor on absolute whole brain metabolism. This data provides preliminary evidence that EPI sequences may affect neuronal activity and merits further investigation.
Use of the third generation mobile phone system is increasing worldwide. This is the first study to investigate the effects of the third generation system on regional cerebral blood flow (rCBF) in humans. We compared effects of the electromagnetic field (EMF) emitted from the Wideband Code Division Multiple Access (W-CDMA) cellular system versus sham control exposure on rCBF in humans. Nine healthy male volunteers participated in this study. Positron emission tomography (PET) scans were obtained before, during, and after unilateral 30 min EMF exposure. The subtraction analysis revealed no significant rCBF changes caused by the EMF conditions compared with the sham exposure, suggesting that EMF emitted by a third generation mobile phone does not affect rCBF in humans.
— A method has been developed for the simultaneous measurement of the rates of glucose consumption in the various structural and functional components of the brain in vivo. The method can be applied to most laboratory animals in the conscious state. It is based on the use of 2-deoxy-D-[14C]glucose ([14C]DG) as a tracer for the exchange of glucose between plasma and brain and its phosphorylation by hexokinase in the tissues. [14C]DG is used because the label in its product, [14C]deoxyglucose-6-phosphate, is essentially trapped in the tissue over the time course of the measurement. A model has been designed based on the assumptions of a steady state for glucose consumption, a first order equilibration of the free [14C]DG pool in the tissue with the plasma level, and relative rates of phosphorylation of [14C]DG and glucose determined by their relative concentrations in the precursor pools and their respective kinetic constants for the hexokinase reaction. An operational equation based on this model has been derived in terms of determinable variables. A pulse of [14C]DG is administered intravenously and the arterial plasma [14C]DG and glucose concentrations monitored for a preset time between 30 and 45min. At the prescribed time, the head is removed and frozen in liquid N2-chilled Freon XII, and the brain sectioned for autoradiography. Local tissue concentrations of [14C]DG are determined by quantitative autoradiography. Local cerebral glucose consumption is calculated by the equation on the basis of these measured values.The method has been applied to normal albino rats in the conscious state and under thiopental anesthesia. The results demonstrate that the local rates of glucose consumption in the brain fall into two distinct distributions, one for gray matter and the other for white matter. In the conscious rat the values in the gray matter vary widely from structure to structure (54-197 μmol/100 g/min) with the highest values in structures related to auditory function, e.g. medial geniculate body, superior olive, inferior colliculus, and auditory cortex. The values in white matter are more uniform (i.e. 33–40 μmo1/100 g/min) at levels approximately one-fourth to one-half those of gray matter. Heterogeneous rates of glucose consumption are frequently seen within specific structures, often revealing a pattern of cytoarchitecture. Thiopental anesthesia markedly depresses the rates of glucose utilization throughout the brain, particularly in gray matter, and metabolic rate throughout gray matter becomes more uniform at a lower level.
The relationship between regional oxidative and total rCMR in five healthy volunteers in activated and non‐activated areas of the brain has been investigated with positron emission tomography (PET). The tracers [l‐ u C]‐D‐glucose and [2‐ ¹⁸ F]2‐fluoro‐2‐deoxy‐D‐glucose were used. A previous study has shown that the former may be used to measure the rate of glucose oxidation while the latter tracer is used to measure the total rate of glucose consumption. Regional activation was performed (voluntary finger movements). Use of a computerized brain atlas enabled comparison between the regional oxidative and total rCMR glc in each volume element of the brain for the group of subjects.
The values of total and oxidative rCMR gle , when calculated for each volume element of the brain and displayed in a scatter plot, were found to be symmetrically grouped around a straight line which passes close to the origin. The slope of this line varied between the subjects. This indicates that, on the average, the fraction of non‐oxidative glucose utilization is constant within each subject, regardless of the value of rCMR gle and, further, that the fraction of non‐oxidative glucose utilization varies between subjects.
The total and oxidative CMR glc in the activated left hand area were 23.4 + 0.9% (mean + SEM) and 11.7 + 0.3%, respectively, higher than in the contralateral homologous non‐activated area. Our interpretation of the difference is that regional activation increases the fraction of non‐oxidative glucose consumption. This interpretation is supported by a previous PET study using [ ¹⁵ 0]O a , and by studies using MRS technique.
The authors assessed the relationship between ventricular enlargement, cortical atrophy, regional brain glucose metabolism, and neuropsychologic performance in 10 alcoholics and 10 control subjects. Regional brain glucose metabolism was measured with fluorine-18 fluorodeoxyglucose (FDG) and positron emission tomography (PET). Cortical atrophy and ventricular size were evaluated quantitatively with magnetic resonance (MR) imaging. Alcoholics had decreased brain glucose metabolism and more cortical atrophy but did not have significantly greater ventricular size than did control subjects. The degree of ventricular enlargement and of cortical atrophy was associated with decreased metabolism predominantly in the frontal cortices and subcortical structures in both alcoholics and control subjects. There were no significant correlations between neuropsychologic performance and MR imaging structural changes, whereas various subtest scores were significantly correlated with frontal lobe metabolism. These data show that F-18 FDG PET is a sensitive technique for detecting early functional changes in the brain due to alcohol and/or aging before structural changes can be detected with MR imaging.
This paper was motivated by a recent article in which the levels of electromagnetic energy absorbed in the heads of mobile phone users were compared for children and adults at the frequencies of 835 MHz and 1,900 MHz. Significant differences were found, in particular substantially greater absorption in children's heads at 835 MHz. These findings contradict other studies in which no significant changes had been postulated. The clarification of this issue is crucial to the mobile communications industry since current SAR evaluations as required by the FCC are only performed with phantoms based on the heads of adults. In order to investigate the differences in absorption between adults and children due to their differing anatomies, simulations have been performed using head phantoms based on MRI scans of an adult (voxel size 2 x 2 x 1 mm3) and two children (voxel size 2 x 2 x 1.1 mm3) of the ages of 3 and 7 y. Ten different tissue types were distinguished. The differences in absorption were investigated for the frequencies of 900 MHz and 1,800 MHz using 0.45 lambda dipoles instead of actual mobile phones. These well-defined sources simplified the investigation and facilitated the comparison to previously published data obtained from several numerical and experimental studies on phantoms based on adults. All simulations were performed using a commercial code based on the finite integration technique. The results revealed no significant differences in the absorption of electromagnetic radiation in the near field of sources between adults and children. The same conclusion holds when children are approximated as scaled adults.
A finite element thermal model of the head has been developed to calculate temperature rises generated in the brain by radiation from cellular telephones and similar electromagnetic devices. A 1 mm resolution MRI dataset was segmented semiautomatically, assigning each volume element to one of ten tissue types. A finite element mesh was then generated using a fully automatic tetrahedral mesh generator developed at NRPB. There are two sources of heat in the model: firstly the natural metabolic heat production; and secondly the power absorbed from the electromagnetic field. The SAR was derived from a finite difference time domain model of the head, coupled to a model 'mobile phone', namely a quarter-wavelength antenna mounted on a metal box. The steady-state temperature distribution was calculated using the standard Pennes 'bioheat equation'. In the normal cerebral cortex the high blood perfusion rate serves to provide an efficient cooling mechanism. In the case of equipment generally available to the public, the maximum temperature rise found in the brain was about 0.1 degrees C. These results will help in the further development of criteria for exposure guidelines, and the technique developed may be used to assess temperature rises associated with SARs for different types of RF exposure.
Although safety guidelines--to which mobile telephones and their base-stations conform--do protect against excessive microwave heating, there is evidence that the low intensity, pulsed radiation currently used can exert subtle non-thermal influences. If these influences entail adverse health consequences, current guidelines would be inadequate. This review will focus on this possibility. The radiation used is indeed of very low intensity, but an oscillatory similitude between this pulsed microwave radiation and certain electrochemical activities of the living human being should prompt concern. However, being so inherently dependent on aliveness, non-thermal effects cannot be expected to be as robust as thermal ones, as is indeed found; nor can everyone be expected to be affected in the same way by exposure to the same radiation. Notwithstanding uncertainty about whether the non-thermal influences reported do adversely affect health, there are consistencies between some of these effects and the neurological problems reported by some mobile-telephone users and people exposed longterm to base-station radiation. These should be pointers for future research.
We employed cerebral (18)Fluoro-deoxyglucose positron emission tomography ([(18)F]FDG-PET) to visualize neuronal activation of the frontal motor and premotor cortex during suprathreshold repetitive transcranial magnetic stimulation (rTMS) applied to the left primary sensorimotor hand area (SM1(HAND)). Twelve right-handed normal subjects underwent two [(18)F]FDG-PET measurements at baseline without rTMS and during suprathreshold 2 Hz rTMS of the left SM1(HAND). In the rTMS condition, 1,800 magnetic stimuli at an intensity of 140% of motor-resting threshold were delivered immediately after intravenous injection of [(18)F]FDG. Relative differences in the normalized regional cerebral metabolic rate for glucose (rCMRglc) between the rTMS condition and baseline were determined using a voxel-by-voxel Student's t-test and a volume-of-interest analysis. Data analysis was a priori restricted to primary motor and premotor areas in the frontal cortex, namely the SM1, the supplementary motor area (SMA), the lateral premotor cortex (PMC), and the caudal anterior cingulate cortex (ACC) of either hemisphere. In addition to a relative increase in normalized rCMRglc in the stimulated SM1(HAND), suprathreshold rTMS was associated with well-localized increases in normalized rCMRglc in the caudal SMA and ACC on the medial wall of the frontal cortex and in the right precentral gyrus in the lateral PMC rostrally to the SM1. These data demonstrate that a selective activation of the SM1(HAND) is paralleled by an activation of a distinct set of remote premotor areas, suggesting a functional interaction between the primary motor and premotor cortex in humans.
Fourteen healthy right-handed subjects were scanned using PET with a [15O]water tracer during exposure to electromagnetic field (EMF) emitted by a mobile phone and a sham-exposure under double-blind conditions. During scanning, the subjects performed a visual working memory task. Exposure to an active mobile phone produced a relative decrease in regional cerebral blood flow (rCBF) bilaterally in the auditory cortex but no rCBF changes were observed in the area of maximum EMF. It is possible that these remote findings were caused by the EMF emitted by the active mobile phone. A more likely interpretation of the present findings were a result of an auditory signal from the active mobile phone. Therefore, it is not reasoned to attribute this finding to the EMF emitted by the phone. Further study on human rCBF during exposure to EMF of a mobile phone is needed.
Cells phenotypically adapt to alterations in their intra- and extracellular environment via organised alterations to gene and protein expression. Many chemical and physical stimuli are known to drive such responses, including the induction of oxidative stress and heat shock. Increasing use of mobile telephones in our society, has brought focus on the potential for radio frequency (microwave) electromagnetic radiation to elicit biological stress responses, in association with potentially detrimental effects of this to human health. Here we review evidence suggesting altered gene and protein expression in response to such emissions, with particular focus on heat shock proteins. Non-thermal induction of heat shock proteins has been claimed by a number of investigations in in vitro cellular systems, and appears pleiotropic for many other regulatory events. However, many of these studies are flawed by inconsistencies in exposure models, cell types used and the independent reproducibility of the findings. Further, the paucity of evidence from in vivo experimentation is largely contradictory. Therefore, the validity of these effects in human health risk assessment remain unsubstantiated. Where possible, suggestions for further experimental clarification have been provided.
We investigated the effects of radio frequency electromagnetic fields (RF EMF) similar to those emitted by mobile phones on waking regional cerebral blood flow (rCBF) in 12 healthy young men. Two types of RF EMF exposure were applied: a 'base-station-like' and a 'handset-like' signal. Positron emission tomography scans were taken after 30 min unilateral head exposure to pulse-modulated 900 MHz RF EMF (10 g tissue-averaged spatial peak-specific absorption rate of 1 W/kg for both conditions) and sham control. We observed an increase in relative rCBF in the dorsolateral prefrontal cortex on the side of exposure. The effect depended on the spectral power in the amplitude modulation of the RF carrier such that only 'handset-like' RF EMF exposure with its stronger low-frequency components but not the 'base-station-like' RF EMF exposure affected rCBF. This finding supports our previous observation that pulse modulation of RF EMF is necessary to induce changes in the waking and sleep EEG, and substantiates the notion that pulse modulation is crucial for RF EMF-induced alterations in brain physiology.
To test-via Transcranial Magnetic Stimulation (TMS)-the excitability of each brain hemisphere after 'real' or 'sham' exposure to the electromagnetic field (EMF) generated by a mobile phone operating in the Global System for Mobile Communication (GSM).
Fifteen male volunteers attended two experimental sessions, one week apart, in a cross-over, double-blind paradigm. In one session the signal was turned ON (EMF-on, real exposure), in the other it was turned OFF (EMF-off, sham exposure), for 45 minutes. Motor Evoked Potentials (MEPs) were recorded using a paired-pulse paradigm (testing intracortical excitability with 1 to 17 ms interstimulus intervals), both before and at different times after exposure to the EMF. Short Intracortical Inhibition (SICI) and Facilitation (ICF) curves were evaluated both on the exposed and non-exposed hemispheres. Tympanic temperature was collected during each session.
The intracortical excitability curve becomes significantly modified during real exposure, with SICI being reduced and ICF enhanced in the acutely exposed brain hemisphere as compared to the contralateral, non-exposed hemisphere or to sham exposure. Tympanic temperature showed no significant main effect or interactions.
These results demonstrate that GSM-EMFs modify brain excitability. Possible implications and applications are discussed.
In human brain, short-term physiological stimulation results in dramatic and proportional increase in blood flow and metabolic rate of glucose but minimal change in oxygen utilization, however, with continuing stimulation, we have observed that blood flow response diminishes and oxygen utilization increases. Given the temporal limitation of conventional methods to measure glucose metabolism in the human brain, we modified [(18)F]fluorodeoxyglucose (FDG) PET paradigm to evaluate the short-term and long-term effects of visual stimulation on human brain glucose metabolism. In the present study, seven healthy volunteers each underwent three dynamic FDG PET studies: at rest and after 1 min and 15 min of visual stimulation (using reversing black-white checkerboard) which continued for only 5 min after FDG injection. We found that increase in FDG uptake in the visual cortex was attenuated by 28% when preceded by 15 min of continuous visual stimulation (p<0.001). This decline in metabolism occurred in the absence of any behavior changes in task performance. The similarity in behavior of blood flow and glucose metabolism over time supports the hypothesis that, in activated brain, blood flow is modulated by changes in cytosolic free NADH/NAD(+) ratio related to increased glycolysis. Furthermore, the observed decline in glucose metabolism may reflect a shift from glycolytic to oxidative glucose metabolism with continued activation.
The brain is a heterogeneous organ with regionally varied and constantly changing energetic needs. Blood vessels in the brain are equipped with control mechanisms that match oxygen and glucose delivery through blood flow with the local metabolic demands that are imposed by neural activity. However, the cellular bases of this mechanism have remained elusive. A major advance has been the demonstration that astrocytes, cells with extensive contacts with both synapses and cerebral blood vessels, participate in the increases in flow evoked by synaptic activity. Their organization in nonoverlapping spatial domains indicates that they are uniquely positioned to shape the spatial distribution of the vascular responses that are evoked by neural activity. Astrocytic calcium is an important determinant of microvascular function and may regulate flow independently of synaptic activity. The involvement of astrocytes in neurovascular coupling has broad implications for the interpretation of functional imaging signals and for the understanding of brain diseases that are associated with neurovascular dysfunction.
Modern mobile phones emit electromagnetic fields (EMF) ranging from 900 to 2000 MHz which are suggested to have an influence on well-being, attention and neurological parameters in mobile phone users. Until now most studies have investigated Global System for Mobile Communications (GSM)-EMF and only very few studies have focused on Universal Mobile Telecommunications System (UMTS)-EMF. Therefore, we tested the effects of both types of unilaterally presented EMF, 1950 UMTS (0.1 and 1 W/kg) and pulsed 900 MHz GSM (1 W/kg), on visually evoked occipital P100, the P300 of a continuous performance test, auditory evoked central N100 and the P300 during an oddball task as well as on the respective behavioral parameters, reaction time and false reactions, in 15 healthy, right handed subjects. A double-blind, randomized, crossover application of the test procedure was used. Neither the UMTS- nor the GSM-EMF produced any significant changes in the measured parameters compared to sham exposure. The results do not give any evidence for a deleterious effect of the EMF on normal healthy mobile phone users.
We measured frequency-dependent functional MRI (fMRI) activations (at 11.7 T) in the somatosensory cortex with whisker and forepaw stimuli in the same alpha-chloralose anesthetized rats. Whisker and forepaw stimuli were attained by computer-controlled pulses of air puffs and electrical currents, respectively. Air puffs deflected (+/-2 mm) the chosen whisker(s) in the right snout in the rostral to caudal direction, and electrical currents (2 mA amplitude, 0.3 ms duration) stimulated the left forepaw with subcutaneous copper electrodes placed between the second and fourth digits. In the same subject, unimodal stimulation of whisker and forepaw gave rise to significant blood oxygen level-dependent (BOLD) signal increases in corresponding contralateral somatosensory areas of whisker barrel field (S1BF) and forelimb (S1FL), respectively, with no significant spatial overlap between these regions. The BOLD responses in S1(BF) and S1(FL) regions were found to be differentially variable with frequency of each stimulus type. In the S1BF, a linear increase in the BOLD response was observed with whisker stimulation frequency of up to approximately 12 Hz, beyond which the response seemed to saturate (and/or slightly attenuate) up to the maximum frequency studied (i.e. 30 Hz). In the S1FL, the magnitude of the BOLD response was largest at forepaw stimulation frequency between 1.5 and 3 Hz, beyond which the response diminished with little or no activity at frequencies higher than 20 Hz. The volume of tissue activated by each stimulus type followed a similar pattern to that of the stimulation frequency dependence. These results of bimodal whisker and forepaw stimuli in the same subject may provide a framework to study interactions of different tactile modules, with both fMRI and neurophysiology (i.e. inside and outside the magnet).
The rapid worldwide increase in mobile phone use in the last decade has generated considerable interest in possible carcinogenic effects of radio frequency (RF). Because exposure to RF from phones is localized, if a risk exists it is likely to be greatest for tumours in regions with greatest energy absorption. The objective of the current paper was to characterize the spatial distribution of RF energy in the brain, using results of measurements made in two laboratories on 110 phones used in Europe or Japan. Most (97-99% depending on frequency) appears to be absorbed in the brain hemisphere on the side where the phone is used, mainly (50-60%) in the temporal lobe. The average relative SAR is highest in the temporal lobe (6-15%, depending on frequency, of the spatial peak SAR in the most exposed region of the brain) and the cerebellum (2-10%) and decreases very rapidly with increasing depth, particularly at higher frequencies. The SAR distribution appears to be fairly similar across phone models, between older and newer phones and between phones with different antenna types and positions. Analyses of risk by location of tumour are therefore important for the interpretation of results of studies of brain tumours in relation to mobile phone use.
Electromag-netic fields, such as those from mobile phones, alter regionalcerebralbloodflowandsleepandwakingEEG
- R Huber
- V Treyer
- Borbe
- Aa
Huber R, Treyer V, Borbe ´ly AA, et al. Electromag-netic fields, such as those from mobile phones, alter regionalcerebralbloodflowandsleepandwakingEEG. J Sleep Res. 2002;11(4):289-295