Satoshi Iwase

Aichi Medical University · Department of Physiology

Hindlimb immobilization (IM) produces a decrease in functional oxidative capacity as well as morphological changes in muscles. However, the effect of IM on the mechanism of O2 supply to mitochondria in muscle tissue during muscle contraction is unknown, especially the contribution of myoglobin (Mb) to mitochondrial respiration. This study investiga...

[This corrects the article DOI: 10.3389/fphys.2021.670640.].

The most likely cause of lower-leg swelling is prolonged sitting, which sometimes induces deep vein thrombosis, also known as, economy class syndrome. We aimed to clarify the influence of intake of 4 G -α-glucopyranosyl hesperidin (G-Hsp) beverage on the lower-leg swelling caused by 6 h of sitting in six healthy women. All subjects ingested 100 mL...

The effects of microgravity conditions on neurovestibular, cardiovascular, musculoskeletal, bone metabolic, and hemato-immunological systems are described. We discuss “space motion sickness,” sensorimotor coordination disorders, cardiovascular deconditioning, muscular atrophy, bone loss, and anemia/immunodeficiency, including their causes and mecha...

Light has a strong effect on the circadian rhythm. Blue light at night has a negative effect on melatonin secretion and sleep quality. Recently, a smart phone is popularly used in the whole day even including night, resulting in the increased rate of insomnia and difficulties of quality of sleep. In the present study, we investigated that the effec...

Background/purpose It is known that the elderly and adult women with reduction in sebum secretion have reduced skin barrier function, drying of the skin in a low humidity environment is accompanied by physiological distress. As our hypothesis, when fine water particles are sprayed on the skin, the water content of the corneal layer is significantly...

Bioelectrical Impedance Analysis (BIA) is adopted as a simple method to measure the body composition including the body fluid volume, muscle volume, and body fat volume in human. Using segmental BIA, we investigated time‐course changes in the body fluid distribution in various body segments with posture change and during −6° head‐down bed rest, reg...

Recently some investigations reported that the reductions in skin elasticity correlated to physiological functions and blood component, and could be useful as the aging index. In women, the elasticity of the face decreases as estrogen production falls with age. In the present study, we measured the skin elasticity of the cheek in young women (the y...

We examined the effect of intake of a catechin-enriched ion beverage (Cat-I) on the thermoregulatory response in a hot environment. Eight healthy men were exposed to a hot environment for 90 min at an ambient temperature of 35 °C (relative humidity: 75%) combined with lower leg water immersion at 40 °C. At that time, either Cat-I, an ion beverage (...

Purpose: To report a case of herpes zoster ophthalmicus with impaired ocular motility. Case: A 66-year-old male had headache for 2 weeks and was diagnosed with herpes zoster ophthalmicus at a department of neurosurgery. He was hospitalized and started receiving acyclovir. Five days later, he developed ptosis of left eyelid, deviation of left eye to...

Under acute hypoxic conditions, the muscle oxygen uptake (mV˙O2) during exercise is reduced by the restriction in oxygen‐supplied volume to the mitochondria within the peripheral tissue. This suggests the existence of a factor restricting the mV˙O2 under hypoxic conditions at the peripheral tissue level. Therefore, this study set out to test the hy...

Skin sympathetic nerve activity (SSNA) is microneurographically recorded from the skin nerve fascicle in the peripheral nerves with properties of an irregular, pulse asynchronous burst with respiratory variation, followed by sweating and/or vasoconstriction, elicited by mental stress and arousal stimuli. It comprises sudomotor and vasoconstrictor n...

Syncope is defined as a transient loss of consciousness and postural tone, characterized by rapid onset, short duration, and spontaneous recovery; the process of syncope progression is here described with two types of sympathetic change. Simultaneous recording of microneurographically recorded muscle sympathetic nerve activity (MSNA) and continuous...

Aim: To test the hypothesis that autonomic neural activity in pregnant women during exercise varies according to gestational age. Methods: This cross-sectional study involved 20 healthy women in their second (n = 13) or third (n = 7) trimester of pregnancy. Incremental cardiopulmonary exercise testing was performed with an electromagnetic cycle...

Key points: We studied healthy astronauts before, during, and after the Neurolab space mission with controlled breathing and apnoea, to identify autonomic changes that might contribute to postflight orthostatic intolerance. Measurements included the electrocardiogram, finger photoplethysmographic arterial pressure, respiratory carbon dioxide level...

Key points: We studied healthy supine astronauts on Earth with electrocardiogram, noninvasive arterial pressure, respiratory carbon dioxide concentrations, breathing depth, and sympathetic nerve recordings. Null hypotheses: Heart beat interval fluctuations at usual breathing frequencies are baroreflex mediated and persist during apnoea; and autono...

This book describes newly developed methods of assessing the autonomic nervous system. Up-to-date information on microneurographic analysis of human cardiovascular and thermoregulatory function in humans, heart rate variability, and 131I-metaiodobenzylguanidine (MIBG) scintigraphy are provided. Microneurography, which was originally developed as a...

During the past several decades, obesity has been increasing globally. In Japan, obesity is defined by a BMI of 25 kg/m 2 or over; 28.6 % of men and 20.6 % of women are obese. Obese people have an increased incidence of developing cardiovascular, renal, and hormonal diseases and sleep disorders. Obese people also have shortened sleep durations. We...

Background: There is no clear information about the optimal bed reclining angle for promoting efficient and safe defecation in bedfast patients. Objective: The aim of this study was to examine the optimal bed reclining angle for facilitating increases in intrarectal pressure without causing marked cardiovascular changes in order to develop an ef...

To examine the effects of micro mist sauna bathing, produced by water crushing method, we exposed ten male subjects to five cases of micro mist sauna, namely (1) room temperature (RT) 38 °C with 100 % (actually 91 %) relative humidity (RH), (2) RT 41.5 °C with 80 % (actually 81 %) RH, (3) RT 41.5 °C with 100 % (actually 96 %) RH, (4) RT 45.0 °C wit...

The purpose of this study was to elucidate the physical effects produced by facial care (FC ； using cosmetics and emulsifiers) performed continuously by elder women, based on the tissue oxygen level in the prefrontal cortex and autonomic nerve response. Eighteen healthy elder women aged 65 years or older (mean age 68±4 years) performed FC continuou...

At onset of muscle contraction, myoglobin (Mb) immediately releases its bound O2 to the mitochondria. Accordingly, intracellular O2 tension (PmbO2) markedly declines in order to increase muscle O2 uptake (mO2). However, whether the change in PmbO2 during muscle contraction modulates mO2 and whether the O2 release rate from Mb increases in endurance...

Objective Arousal stimuli evoke bursts of skin sympathetic nerve activity (SSNA). SSNA usually contains sudomotor and vasoconstrictor neural spikes. The aim of this study was to elucidate which components of event-related potentials (ERPs) are related to sudomotor and vasoconstrictor responses comprising arousal SSNA bursts. Methods We recorded SS...

Syncope is defined as a transient loss of consciousness and postural tone, characterized by rapid onset, short duration, and spontaneous recovery, and the process of syncope progression is here described with two types of sympathetic change. Simultaneous recordings of microneurographically-recorded muscle sympathetic nerve activity (MSNA) and conti...

Background/purposeBy performing experiments in air-conditioned chamber, we previously demonstrated that the presence of water nanodroplets (mist) improved facial skin moisture levels without reducing water loss from the facial skin surface or inducing excessive humidity. Some previous studies have demonstrated that the epidermis is a less effective...

Sweating is an important mechanism for ensuring constant thermoregulation, but hyperhidrosis may be disturbing. We present five cases of hemifacial hyperhidrosis as a compensatory response to an/hypohidrosis caused by cervical disc herniation. All the patients complained of hemifacial hyperhidrosis, without anisocoria or blepharoptosis. Sweat funct...

This study investigates a concentric bipolar active (CBA) electrode with ultra-high input impedance for noninvasive measurement of biopotentials from the autonomic nervous system (ANS). Experiments involving Valsalva maneuvers (VM) conducted with 4 male subjects showed spike-like potentials that resembled neural potentials recorded directly with mi...

The purpose is to investigate the 90-min sleep-related rhythm of intestinal motility in constipated women by spectral analysis of electrogastrograms (EGG). Constipation is classified into two types, spastic and flaccid. The study was performed on 51 subjects who slept for 300 min. We evaluated the amplitude of 90-min cycle and maximal time (lag-tim...

To clarify the effects of isometric and isotonic exercise during mist sauna bathing on the cardiovascular function, thermoregulatory function, and metabolism, six healthy young men (22 ± 1 years old, height 173 ± 4 cm, weight 65.0 ± 5.0 kg) were exposed to a mist sauna for 10 min at a temperature of 40 °C, and relative humidity of 100 % while perfo...

To reduce the risks of Japanese-style bathing, half-body bathing (HBLB) has been recommended in Japan, but discomfort due to the cold environment in winter prevents its widespread adoption. The development of the mist sauna, which causes a gradual core temperature rise with sufficient thermal comfort, has reduced the demerits of HBLB. We examined h...

Background/purposeIn air-conditioned rooms, dry air exacerbates some skin diseases, for example, senile xerosis, atopic dermatitis, and surface roughness. Humidifiers are used to improve air dryness, which often induces excess humidity and thermal discomfort. To address this issue, we investigated the effects of water nanodroplets (mist) on skin hy...

Both spectral power within the low-frequency component, i.e., 0.04 to 0.15Hz, of systolic pressure and muscle sympathetic nerve activity are increased during head-up tilt. The nerve activity during tilt is altered after space flight and exposure to simulated microgravity. In the present study, correlations of the low-frequency component and the ner...

Mist sauna is a style of bathing in which hot water vapor is sprayed into a bathroom, establishing an air temperature of 40°C with saturated humidity. Bath heater and dryer equipment with mist sauna function was released onto the Japanese market in 2004. After their introduction, various studies investigated the effects of mist sauna bathing, and i...

Due to its proximity to Earth, the Moon is a promising candidate for the location of an extra-terrestrial human colony. In addition to being a high-fidelity platform for research on reduced gravity, radiation risk, and circadian disruption, the Moon qualifies as an isolated, confined, and extreme (ICE) environment suitable as an analog for studying...

During the past several decades, obesity has been increasing globally. In Japan, obesity is defined by a BMI of 25 kg/m(2) or over; 28.6 % of men and 20.6 % of women are obese. Obese people have an increased incidence of developing cardiovascular, renal, and hormonal diseases and sleep disorders. Obese people also have shortened sleep durations. We...

Obese subjects may be more vulnerable to injury from heat stress, and appear to be less efficient at thermoregulation. Sweat rate, tympanic temperature and osmolality in obese subjects were investigated in Japan during two seasons. The purpose of this study was to examine the relationship between obesity, thermoregulatory response and season. Five...

The effects of environmental temperature on blood pressure and hormones in obese subjects in Japan were compared in two seasons: summer vs winter. Five obese (BMI, 32 ± 5 kg/m(2)) and five non-obese (BMI, 23 ±3 kg/m(2)) men participated in this experiment at latitude 35°10' N and longitude 136°57.9' E. The average environmental temperature was 29 ±...

Acquired idiopathic generalized anhidrosis (AIGA) is a rare disorder in which systemic anhidrosis occurs in the absence of any causative skin, metabolic, or neurological disorder.(1) Treatment of AIGA almost always comprises steroid pulse therapy or high-dose oral steroids.(2-6) However, few previous reports have addressed the course of treatment f...

Frequency-domain analyses of simultaneously recorded skin and muscle sympathetic nerve activities may yield unique information on otherwise obscure central processes governing human neural outflows. We used wavelet transform and wavelet phase coherence methods to analyse integrated skin and muscle sympathetic nerve activities and haemodynamic fluct...

Three-dimensional (3D) television sets are available in the market and are becoming increasingly popular among consumers. However, viewing 3D films has potential adverse effects such as asthenopia and visually induced motion sickness (VIMS). The phenomenon of VIMS is not fully understood yet. One cause of VIMS has been considered to be sensory conf...

In this study, after confirming the suppression of autonomic nervous function by isoflurane anesthesia using autonomic antagonists, we pharmacologically investigated the involvement of vasomotor and cardiac sympathetic functions in systolic blood pressure variability (SBPV) frequency components in conscious rats at rest and during exposure to low-a...

Physiological functions are impaired in various organs in aged people, as manifest by, e.g., renal and cardiac dysfunction and muscle atrophy. The elderly are also at increased risk of both hypothermia and hyperthermia in extreme temperatures. The majority of those over 65 years old have elevated serum osmolality. Our hypothesis is that the elderly...

In summer and winter, young, sedentary male (N = 5) and female (N = 7) subjects were exposed to heat in a climate chamber in which ambient temperature (Ta) was raised continuously from 30 to 42°C at a rate of 0.1°C min(-1) at a relative humidity of 40%. Sweat rates (SR) were measured continuously on forearm, chest and forehead together with tympani...

Objectives: Constipation affects as many as 26% of elderly men and 34% of elderly women and is a problem that has been related to a diminished quality of life. The aim of this study was to investigate the influence of aging on electrogastrograms (EGGs). On the basis of the EGGs of elderly individuals, the effect of hot stupe application on the epi...

Heat acclimation results in whole body-adaptations that increase heat tolerance, and might also result in changed immune responses. We hypothesized that, after heat acclimation, tumor necrosis factor alpha, interleukin 6 and the lymphocyte count would be altered. Heat acclimation was induced in 6 healthy men by 100 min of heat exposure for 9 days....

When returning on the earth by the space flight, the space deconditioning may be developed. As this countermeasure, the artificial gravity load device using the centrifuge is proposed in the space station. But the gravity load might cause the faint, and safe gravity load is uncertainty. We proposed that discriminate strength of gravity tolerance us...

In order to elucidate the effects of deconditioning (inactivity) on the ventilatory and circulatory responses at the onset of exercise within 20 s, we initiated head-down bed rest and unilateral lower limb suspension experiments, and measured these responses to dynamic voluntary leg exercise and passive movements. Initial ventilatory and heart rate...

Bone loss is one of the most important complications for astronauts who are exposed to long-term microgravity in space and also for bedridden elderly people. Recent studies have indicated that the sympathetic nervous system plays a role in bone metabolism. This paper reviews findings concerning with sympathetic influences on bone metabolism to hypo...

In order to obtain evidence that Mb releases O(2) during muscle contraction, we have set up a buffer-perfused hindlimb rat model and applied NIRS to detect the dynamics of tissue deoxygenation during contraction. The NIRS signal was monitored on hindlimb muscle during twitch contractions at 1 Hz, evoked via electrostimulator at different submaximal...

Although the O(2) gradient regulates O(2) flux from the capillary into the myocyte to meet the energy demands of contracting muscle, intracellular O(2) dynamics during muscle contraction remain unclear. Our hindlimb perfusion model allows the determination of intracellular myoglobin (Mb) saturation ( ) and intracellular oxygen tension of myoglobin...

The aim of this study was to investigate the consequences of 20 days of physical inactivity induced by simulated microgravity using head‐down bed rest (HDBR) at −6° on leptin, ghrelin and counterregulatory hormone response. Eight male volunteers were subjected to HDBR for 20 days. Variables measured before, during and after HDBR included plasma cor...

We investigated the effect of passive heating on thermoregulatory responses and subjective sensation. Six volunteers were subjected for the experiment at latitude 35°N; in which the mean temperature and hours of daylight were 7.3°C and 11:21 hours in winter. Subjects entered a climatic chamber at 40°C and 50%RH for 90 min for 14 days. Core and skin...

The aim of this study was to investigate the consequences of 20 d of physical inactivity using head-down bed rest (HDBR) at -6 degrees on leptin, ghrelin, and counter-regulatory hormone responses. Eight male volunteers were subjected to HDBR for 20 d. Variables measured before, during, and after HDBR included plasma cortisol, insulin, glucose, lept...

We investigated seasonal changes in hormonal and thermoregulatory responses. Eight volunteers were subjected to the experiment at four times of the year: around the vernal and autumnal equinoxes, and at the summer and winter solstices at latitude 35 degrees N. Plasma antidiuretic hormone (ADH), angiotensin II (ANG II), aldosterone (ALD) and plasma...

Recently, there has been an increasing focus on the rapid reduction of muscles that are required for the bending of the hip joint during walking (flexor muscles around the hip joint) with age. The flexor muscles around the hip joint include femoral rectus and abdominal muscles. These muscles have been implicated in falling in the elderly. In this s...

Hemifacial flushing and contralateral anhidrosis in adulthood are sometimes observed in sympathetic trunk lesion, including mass lesion, thoracic outlet syndrome, or malignant tumor. However, we observed the symptom in three young boys, possibly due to damage at delivery. Case 1, an one-year and nine-month old boy, had the right hemifacial flushi...

The present study examines the prevalence of subjective fatigue in young healthy males during 14 days of 6° head-down bed rest (HDBR) by using a multidimensional questionnaire. Forty-one subjects completed the Subjective Fatigue Scale questionnaire to assess the fatigue-related complaints and symptoms. The questionnaire is composed of three section...

We tested the hypothesis that encouraged water drinking according to urine output for 20 days could ameliorate impaired thermoregulatory function under microgravity conditions. Twelve healthy men, aged 24 +/- 1.5 years (mean +/- SE), underwent -6 degrees head-down bed rest (HDBR) for 20 days. During bed rest, subjects were encouraged to drink the s...