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ABSTRACT: Cobalt nanoparticles (CoNPs) are produced for several industrial and biomedical applications but there is a lack of data on human cutaneous absorption. Cobalt is also a skin sensitizer that can cause allergic contact dermatitis. Co applied as NPs, due to their small size and high surface, can penetrate into the skin in higher amount that bulk material. The aim of this study was to evaluate the absorption of Co applied as NPs in both intact and damaged skin. Experiments were performed using Franz cells and 1.0mgcm(-2) of CoNPs was applied as donor phase for 24h. Mean Co content of 8.5±1.2ngcm(-2) and 1.87±0.86μgcm(-2) were found in the receiving solutions of Franz cells when the CoNPs suspension was applied on intact skin and on damaged skin, respectively. Twenty-four hours Co flux permeation was 76±49ngcm(-2)h(-1) in damaged skin with a lag time of 2.8±2.1h. This study suggests that Co applied as NPs is able to penetrate the human skin in an in vitro diffusion cell system.
Toxicology in Vitro 09/2012; · 2.78 Impact Factor
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ABSTRACT: Salivary cortisol offers a novel approach to understand the relationship between psychosocial environment and health. This study examines the intra-individual relationships among indicators of the cortisol circadian rhythm and investigates the influence of determinants affecting the day-to-day variability of the cortisol measures. Over three weekdays, 87 healthy subjects (63 females and 24 males) collected saliva samples at seven time points to assess the cortisol awakening response (CAR), and to evaluate the post morning cortisol profile. The generalized estimating equations method was used to explore the relations between repeated cortisol measures and potential determinants (sociodemographic, health, and sampling factors) influencing salivary cortisol levels. Younger age, being smoker, and sampling on a working day were associated with higher at awakening and total cortisol excretion in the morning period. Higher overall cortisol excretion and cortisol increase in the first hour of the day were found for adherents to sampling procedure. Higher educational level was found associated with greater total cortisol excretion in the morning and post morning period, while a flatter diurnal slope was found in smokers. Results are consistent with the knowledge that the circadian cortisol rhythm is differentially determined by situational factors and that results obtained in the early morning hour are of crucial importance corroborating the evidence that the CAR is a highly state-dependent phenomenon. These data indicate that many confounding factors need to be controlled when using salivary cortisol as biomarker of the mind-health interrelationship.
Toxicology Letters 08/2011; 213(1):21-6. · 3.23 Impact Factor
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ABSTRACT: To examine the association between two job stress models-the job strain (JDC) and the effort-reward imbalance (ERI) model-and ambulatory blood pressure monitoring in call handler operators.
Participants included 74 women (age, 34.9 ± 9.9 years) and 26 men (age 36.0 ± 10.8 years) who were monitored on 2 workdays for ambulatory blood pressure. Measures of both job stress models were related to blood pressure by the generalized estimating equations (GEE) method while adjusting for potential confounders (gender, age, cigarette smoking, alcohol consumption, educational level, marital status, time of day, and work schedule).
Workshifts were associated with an increase of 3-4 and 14 mmHg in mean arterial pressure (MAP) compared with diurnal activities out of work and sleeping period, respectively (P < 0.001). Ambulatory blood pressure was also significantly related with work schedule preference: unpleasant work schedule was associated with an increase of 2 mmHg in MAP compared with pleasant work schedule (P = 0.013). In the ERI model, subjects scoring high in work stress have higher ambulatory blood pressure at work, at home, and during sleep. Work stress by time interaction was not longer significant when controlling for potential confounders: generalized estimating equations revealed that MAP was influenced by BMI (>25 vs. <25: 0.7 (0.2-1.1) mmHg), workshift preference (unpleasant vs. pleasant: 2 (0.4-3.6) mmHg), and time of day. Weak not significant relation was found between ABP and psychosocial factors evaluated by the JDC and ERI models.
These results do not support work stress as a significant factor influencing ABP in a homogeneous group of call-handlers. Complementary information independently obtained from the two work stress models could provide more exhaustive explanations on the stress-related effects on blood pressure.
Archiv für Gewerbepathologie und Gewerbehygiene 04/2011; 84(4):383-91. · 1.89 Impact Factor
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ABSTRACT: Gold nanoparticles (AuNPs) are produced for many applications but there is a lack of available data on their skin absorption. Experiments were performed using the Franz diffusion cell method with intact and damaged human skin. A physiological solution was used as receiving phase and 0.5 mL (1st exp) and 1.5 mL (2nd exp) of a solution containing 100 mg L⁻¹ of AuNPs (15 and 45 μg cm⁻², respectively) was applied as donor phase to the outer surface of the skin for 24 h. Skin absorption was dose dependent. Mean gold content of 214.0 ± 43.7 ng cm⁻² and 187.7 ± 50.2 ng cm⁻² were found in the receiving solutions of cells where the AuNPs solution was applied in higher concentration on intact skin (8 Franz cells) and on damaged skin (8 Franz cells), respectively. Twenty-four hours gold flux permeation was 7.8 ± 2.0 ng cm⁻² h⁻¹ and 7.1 ± 2.5 ng cm⁻² h⁻¹ in intact and damaged skin, respectively, with a lag time less than 1 hour. Transmission Electron Microscope analysis on skin samples and chemical analysis using Inductively Coupled Plasma-Mass Spectrometry demonstrated the presence of AuNPs into epidermis and dermis. This study showed that AuNPs are able to penetrate the human skin in an in vitro diffusion cell system.
Nanotoxicology 02/2011; 5(4):493-501. · 5.76 Impact Factor
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Advanced Engineering Materials 07/2010; 12(7):B276 - B282. · 1.18 Impact Factor
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Advanced Engineering Materials 07/2010; 12(7):B309 - B319. · 1.18 Impact Factor
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ABSTRACT: A 3D-glass-ceramic scaffold for bone tissue engineering with an interconnected macroporous network of pores was doped with silver ions in order to confer antibacterial properties. For this purpose, silver ions were selectively added to the scaffold surfaces through ion-exchange using an aqueous silver nitrate solution. The silver-doped scaffolds were characterized by means of leaching, in vitro antibacterial, and citotoxicity tests. In particular, the silver effect was examined through a broth dilution test in order to evaluate the proliferation of bacteria by counting the colonies forming units. Moreover, cytotoxicity tests were carried out to understand the effect of silver-containing scaffolds on cell adhesion, proliferation, and vitality. For all tests a comparison between silver-doped scaffold and silver-doped scaffold dry sterilized was performed.
Journal of Biomaterials Applications 03/2010; 25(6):595-617. · 2.08 Impact Factor
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ABSTRACT: INTRODUCTION: Nanotechnologies are among the fastest growing areas of scientific research and have important applications in a wide variety of fields. The data suggest that in the future workers and consumers exposed to nanoparticles will significantly increase. DERMAL ABSORPTION AND TOXICITY OF NANOPARTICLES: At now there are gaps in understanding about the human and environmental risk that manufactured nanoparticles pose for occupational exposed people and for consumers. There is a need for assessing the health and environmental impacts, the nanoparticles life cycle, the human exposure routes, the behavior of nanoparticles in the body, and the risk for workers. Possible routes of entry into the body include inhalation, absorption through the skin or digestive tract, injection, and absorption or implantation for drugs delivery systems. In particular, dermal absorption and skin penetration of nanoparticles needs a better evaluation because few and contradictory data are present in the literature, mainly on titanium dioxide. CONCLUSIONS: There are limited data on carbon-based nanoparticles and very few data on other metal nanoparticles increasingly used in industry. The article reviews the literature on the percutaneous absorption of nanoparticles and their effect on skin.
Archiv für Gewerbepathologie und Gewerbehygiene 09/2009; 82(9):1043-55. · 1.89 Impact Factor
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ABSTRACT: To investigate the association between two job stress models-the job demand-control model and the effort-reward imbalance model-and repeated measures of salivary cortisol among male and female call-centre operators.
Daily cortisol profiles consisting of seven time points were measured across two workdays and one leisure day to determine the cortisol awakening response and the cortisol output in the day in 104 volunteers. The employees completed two self-administered questionnaire--the Karasek's demand-control questionnaire and the Siegrist's effort-reward imbalance questionnaire-to assess psychosocial hazards at work. The relations between the perceived workload measures and salivary cortisol levels were analyzed by means of generalized estimating equations method after adjusting for potential confounders (gender, age, educational level, marital status, morning awakening time, sleep duration and quality, weekdays, work schedule, adherence to sampling procedure).
The total cortisol amount excreted in the awakening period was positively associated with the job strain measures (high strain vs. low strain: 1.4 (2.4-0.3) nmol/l). In contrast, individuals scoring higher in effort-reward imbalance at work had both lower cortisol awakening response (high imbalance vs. low imbalance: -0.7 (-1.3 to -0.2) nmol/l) and lower diurnal secretory activity (-9.2 (-17.7 to -0.7) nmol/l). Gender, weekday and adherence to sampling schedule significantly influenced the cortisol excretion in the morning period.
Our results indicate that the two work stress models differentially affect salivary cortisol output. This finding suggests that combining the information from two complementary job stress models results in improved knowledge on the psychobiological correlates of the psychosocial work environment.
Archiv für Gewerbepathologie und Gewerbehygiene 07/2009; 82(9):1141-50. · 1.89 Impact Factor
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ABSTRACT: The bioavailability of metals, which are known as important contact allergens, is decisive for the development and the maintenance of contact dermatitis. The aim of this study was to evaluate the percutaneous penetration of metal powders of cobalt (Co), nickel (Ni) and chromium (Cr) and the effect of skin lesions on skin absorption. In vitro permeation experiments were performed using the Franz diffusion cells with intact and damaged human skin. Physiological solution was used as receiving phase and metal powders (Co, Ni and Cr) dispersed in synthetic sweat at pH 4.5 were applied as donor phase to the outer surface of the skin for 24h. The amount of each metal permeating the skin was analysed by electro-thermal atomic absorption spectroscopy (ETAAS). Donor solution analysis demonstrated that metals were present as ions. Measurements of metals skin content were also exploited. Median Co and Ni concentrations found in the receiving phase were significantly higher when Co and Ni powders were applied on the abraded skin than after application on the intact skin (3566 and 2631ngcm(-2) vs. 8.4 and 31ngcm(-2), respectively). No significant difference was found in Cr permeation through intact and damaged skin. The measurement of metals skin content showed that Co, Ni and Cr concentrations were significantly higher in the damaged skin than in the intact skin. Co and Ni ions concentrations increased significantly when the donor solutions were applied on the damaged skin, while Cr ions concentrations did not increase. This study demonstrated that Co and Ni powders can permeate through damaged skin more easily than Cr powder, which has probably a stronger skin proteins binding capacity. Therefore, our results suggest that is necessary to prevent skin contamination when using toxic substances because a small injury to the skin barrier can significantly increase skin absorption.
Toxicology in Vitro 07/2009; 23(4):574-9. · 2.78 Impact Factor
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ABSTRACT: Experimental and clinical evidence suggest that stress can lead to ill-health through the disregulation of the hypothalamic-pituitary-adrenal (HPA) axis. Studies to date have produced equivocal results likely due to different methodologies and failure to account for confounding factors. This investigation aimed to assess the relation between self-reported work-related stressors and salivary cortisol and to clarify the role of the potential confounders.
Thirty-six call-handlers completed a self-administered job content questionnaire and collected seven daily salivary samples on two workdays and a weekend. The diurnal salivary cortisol output was expressed as cortisol awakening response (CAR), and cortisol output in the rest of the day. Salivary cortisol data were normalized by means of square root transformation. The generalized estimating equations method was used to assess the relation between job strain and cortisol levels after adjusting for gender, weekdays and adherence to the sampling schedule.
Job strain significantly influenced the total amount of cortisol response to waking (high strain vs. low strain: 1.1 (0.3-2.0) nmol/L). The cortisol response to waking showed gender-specific differences [women excreting greater cortisol than men: 1.1 (0.3-1.9) nmol/L], and weekday differences [workdays vs. weekend: 1.0 (0.3-1.6) nmol/L]. Non-compliance with the sampling protocol was associated with lower salivary cortisol than in adherent subjects.
Our results provide further evidence for the HPA axis involvement in the physiological response to work stress. The measure of the CAR showed to be the sensitive index to assess the physiological response to psychosocial factors. Gender, weekday, and protocol compliance were confounding factors.
American Journal of Industrial Medicine 12/2008; 52(3):251-60. · 1.63 Impact Factor
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ABSTRACT: There is a growing interest on nanoparticle safety for topical use. The benefits of nanoparticles have been shown in several scientific fields, but little is known about their potential to penetrate the skin. This study aims at evaluating in vitro skin penetration of silver nanoparticles. Experiments were performed using the Franz diffusion cell method with intact and damaged human skin. Physiological solution was used as receiving phase and 70 microg/cm2 of silver nanoparticles coated with polyvinylpirrolidone dispersed in synthetic sweat were applied as donor phase to the outer surface of the skin for 24h. The receptor fluid measurements were performed by electro thermal atomic absorption spectroscopy (ETAAS). Human skin penetration was also determined by using transmission electron microscope (TEM) to verify the location of silver nanoparticles in exposed membranes. Median silver concentrations of 0.46 ng cm(-2) (range <LOD-2.23) and 2.32 ng cm(-2) (range 0.43-11.6) were found in the receiving solutions of cells where the nanoparticles solution was applied on intact skin (eight cells) and on damaged skin (eight cells), respectively. Twenty-four hours silver flux permeation in damaged skin was 0.62+/-0.2 ng cm(-2) with a lag time <1h. Our experimental data showed that silver nanoparticles absorption through intact and damaged skin was very low but detectable, and that in case of damaged skin it was possible an increasing permeation of silver applied as nanoparticles. Moreover, silver nanoparticles could be detected in the stratum corneum and the outermost surface of the epidermis by electron microscopy. We demonstrated for the first time that silver applied as nanoparticles coated with polyvinylpirrolidone is able to permeate the damaged skin in an in vitro diffusion cell system.
Toxicology 10/2008; 255(1-2):33-7. · 3.68 Impact Factor
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ABSTRACT: The present study tried to investigate, using a synthetic sweat at pH 4.5, whether metallic chromium can pass through the skin (in vitro) and the effect of rapid skin decontamination with a common detergent. A suspension of chromium powder in synthetic sweat at pH 4.5 was prepared and shaken with a stirring plate at room temperature for 30 min. Human skin membranes were set up in Franz-diffusion cells and 1 ml of the freshly made suspension was applied to the outer surface of the skin for 24h. The tests were performed without and with decontamination using the cleanser 30 min after the start of exposure. The appearance of metal ions in the aqueous receptor phase was quantified by Electro Thermal Atomic Absorption Spectroscopy (ETAAS) and Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES). Speciation analysis and measurements of chromium skin content were also performed. Chromium skin permeation was demonstrated in in vitro experiments using the Franz cell system, giving a permeation flux of 0.84+/-0.25 ng cm(-2)h(-1) and a lag time of 1.1+/-0.7h. The cleaning procedure stop Cr permeation but its concentration into the skin significantly increased (Mann-Whitney U test P<0.03). The results revealed that chromium applied as powder can pass through the skin and that decontamination, done after 30 min of exposure, prevent Cr skin permeation but increase Cr content into the skin.
Toxicology in Vitro 06/2008; 22(6):1562-7. · 2.78 Impact Factor
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ABSTRACT: To investigate the association between work stress measures and salivary cortisol excretion in working and weekend days.
In a sample of 68 healthy young call-centre operators dimensions of job stress from the demand-control model were related to repeated measures of salivary cortisol on seven samples (at awakening, +30 min, +60 min, + 3 h, +6 h, +9 h, and +12 h after awakening) at two working days and a weekend day.
The cortisol excretion on work days was higher than during weekend day with gender-specific differences as women only showed higher significant values for area under the curve (AUC(G)) and Diurnal cycle (chi(2) (2) = 8.10, P < 0.05; chi(2) (2) = 15.75, P < 0.05, respectively). There were no associations between job demand, job control and cortisol excretion, while the sociodemographic characteristics of the call-centre operators showed linear relation with the diurnal pattern of cortisol secretory activity.
The hypothalamic-pituitary adrenocortical axis activation was higher in working day than in weekend day. This activation measured by salivary cortisol was not related to self-reported mental stressors assessed with job strain model. The availability of more specific psychometric scales would be useful to explore the relationship between salivary cortisol levels and measures of mental stress at workplace.
Archiv für Gewerbepathologie und Gewerbehygiene 02/2008; 81(4):391-400. · 1.89 Impact Factor
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Pietro Sartorelli,
Heinz W Ahlers,
Kristiina Alanko,
Chen Chen-Peng,
John W Cherrie,
Hans Drexler,
Sanja Kezic,
Gunnar Johanson,
Francesca Larese Filon, Giovanni Maina,
Loretta Montomoli,
Jesper Bo Nielsen
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ABSTRACT: The ICOH Scientific Committee on Occupational and Environmental Dermatoses organized an International Workshop on "Dermal risk assessment at workplace" with the aim of focussing on the different ways of approaching the concept of skin notation (S) for chemicals. The Workshop participants presented their ideas on several aspects of S such as the problems related to the absorption through the compromised skin, the different approaches to S and models that can be used as alternatives to S. Participants agreed to produce a position paper with the goal of exploring the actions needed to improve the S system towards international harmonization. They consider that further discussions are needed to obtain an international consensus, but at the same time they believe that by improving and harmonizing systems for setting S we can make an important contribution to improving health of people with potential dermal exposure to chemicals at work.
Regulatory Toxicology and Pharmacology 01/2008; 49(3):301-7. · 2.43 Impact Factor
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ABSTRACT: It is well known that contact with metals can be responsible for allergic contact dermatitis; also, there is experimental evidence that nickel ions are readily available on the surface of used coins containing nickel and copper. The aim of this study was to prove that metal powders of nickel (Ni), cobalt (Co) and chromium (Cr) dispersed in synthetic sweat are oxidised into respective ions that can permeate the skin. Suspensions of 5 g of metal powder (Ni, Co and Cr) in 100 mL of synthetic sweat at pH 6.5 were prepared and shaken with a stirring plate at room temperature for 30 min. Human skin membranes were set up in Franz-diffusion cells and 2 mL of the freshly made suspension were applied to the outer surface of the skin for 24h. The appearance of metal ions in the aqueous receptor phase (NaCl 0.9%) was quantified by Electro Thermal Atomic Absorption Spectroscopy (ETAAS). Also, metals ions were analysed using Differential Pulse Polarography (DDP), Differential Pulse Voltammetry (DPV) and Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) techniques both in the receiving phase and in the donor solution to evaluate the presence of different ionic metallic species. DPP and DPV measurements of cobalt and nickel suspensions confirmed the presence of Co2+ and Ni2+ ions in concentration, respectively of 33.3+/-3.2 and 27.1+/-3.2 mg L(-1). Chromium ions concentration below 0.1 mg L(-1) were found in chromium suspensions bearing evidence of synthetic sweat inefficacy of oxidising chromium metal powder. Cobalt and nickel skin permeation was demonstrated in in vitro experiments using the Franz cell system giving a permeation flux of 0.0123+/-0.0054 microg cm(-2) h(-1) for cobalt and of 0.0165+/-0.00036 microg cm(-2) h(-1) for nickel and a lag time of 1.55+/-0.71 h for cobalt and of 14.56+/-0.56 for nickel. Chromium below 0.1 microg L(-1) was found in the receiving solutions. Our experiments demonstrated that metallic nickel and cobalt can be oxidised when suspended in synthetic sweat, while chromium would probably need stronger oxidising conditions. Metallic ions can permeate the skin and the Franz cell system showed that it is possible to measure a flux of ions through the skin for cobalt and nickel but not for chromium.
Toxicology Letters 05/2007; 170(1):49-56. · 3.23 Impact Factor
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ABSTRACT: Polycyclic aromatic hydrocarbons have mutagenic and carcinogenic properties and some of them are classified as probable or possible human carcinogens. Aim of this study was to evaluate the genotoxic risk in workers exposed to diesel exaust. Environmental and biological monitoring exposure to polycyclic aromatic hydrocarbons was carried out on fifty-two workers exposed to diesel exhaust. Urinary 1-hydroxypyrene was employed as a biomarker of internal dose. Significant urinary 1-hydroxypyrene differences between smokers and non-smokers were found. Twenty per cent of urinary 1-hydroxypyrene values exceeded benchmark level for genotoxic effect, while the results of environmental monitoring excluded the existence of exposure to polycyclic aromatic hydrocarbons. In the absence of greater knowledge about the relationship between urinary 1-hydroxypyrene and genotoxic effects under the conditions of very low exposure, extreme caution is recommended when this biomarker of internal dose is employed as an indicator of genotoxic risk.
Toxicology and Industrial Health 03/2007; 23(1):55-9. · 1.42 Impact Factor
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ABSTRACT: The aim of this study was to investigate the percutaneous penetration of lead oxide (PbO) powder and the effect of rapid skin decontamination with two different detergents.
Franz cells were used to study in vitro PbO skin penetration through human skin during a 24-hour period. The tests were performed without or with decontamination using either Ivory Liquid soap or a new experimental cleanser 30 minutes after the start of exposure.
We confirm that PbO can pass through the skin with a median penetration of 2.9 ng/cm (25-75th percentiles 0.35-6). The cleaning procedure using Ivory Liquid soap significantly increased skin penetration with a median value of 23.6 ng/cm (25-75th percentiles 12-47.1; Mann-Whitney U test, P = 0.0002), whereas the new experimental cleanser only marginally increased penetration (7.1 ng/cm).
Our results indicate that it is necessary to prevent skin contamination from occurring because a short contact can increase skin content and penetration even if quickly followed by washing. This study demonstrated that PbO powder can pass through the skin and that skin decontamination done after 30 minutes of exposure did not decrease skin absorption occurring over 24 hours and stresses the need to prevent skin contamination when using toxic substances.
Journal of Occupational and Environmental Medicine 08/2006; 48(7):692-9. · 2.06 Impact Factor
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ABSTRACT: Ti-6Al-7Nb samples treated by innovative multi-step chemical and thermal processes were characterized in order to evaluate their surface properties and cell interaction. The main object was to asses if the treatments were effective in order to obtain a surface presenting at the same time bone-like apatite induction ability, low metal ion release, good cell response and high protein binding. The morphology, crystallographic structure, porosity and wettability of the treated materials were investigated, as well as their interaction with simulated body fluid during soaking for different times. Cytotoxicity, protein adsorption tests and in vitro fibroblast and osteoblast-like cell cultures were also performed.
Biomaterials 05/2005; 26(11):1219-29. · 7.40 Impact Factor
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ABSTRACT: To evaluate skin absorption of cobalt powder in an in vitro system. Experiments with volunteers show that cobalt powder can permeate through the skin, but there are no data with regard to the mechanism or the amount of permeation.
Skin permeation was calculated by the Franz diffusion cell method with human skin. A physiological solution was used as receiving phase and the cobalt powder was dispersed in synthetic sweat. The amount of metal passing through the skin was analysed by electro-thermal atomic absorption spectrometry (ETAAS). Parallel polarographic analysis (differential pulse polarography-DPP) allowed evaluation of cobalt present as ions (Co(2+)) in donor and receiving phases. Measurements of cobalt skin content were also performed.
Evaluation of metal in the receiving phase allowed us to demonstrate the permeation of cobalt through the skin. Steady-state flow of percutaneous cobalt permeation was calculated as 0.0123+/-0.0054 microg cm(-2) h(-1), with a lag time of 1.55+/-0.71 h.
The experiments show that cobalt powder can pass through the skin when applied as a dispersion in synthetic sweat, oxidising metallic cobalt into ions, which permeate the skin. These experiments show for the first time how cobalt can permeate the skin.
Archiv für Gewerbepathologie und Gewerbehygiene 03/2004; 77(2):85-9. · 1.89 Impact Factor
