Human biomonitoring of aluminium after a single, controlled manual metal arc inert gas welding process of an aluminium-containing worksheet in nonwelders.

PURPOSE: Several existing field studies evaluate aluminium welding works but no thoroughly controlled exposure scenario for welding fume has been described yet. This study provides information about the uptake and elimination of aluminium from welding fumes under controlled conditions. METHODS: In the Aachen Workplace Simulation Laboratory, we are able to generate welding fumes of a defined particle mass concentration. We exposed 12, until then occupationally unexposed participants with aluminium-containing welding fumes of a metal inert gas (MIG) welding process of a total dust mass concentration of 2.5 mg/m(3) for 6 h. Room air filter samples were collected, and the aluminium concentration in air derived. Urine and plasma samples were collected directly before and after the 6-h lasting exposure, as well as after 1 and 7 days. Human biomonitoring methods were used to determine the aluminium content of the samples with high-resolution continuum source atomic absorption spectrometry. RESULTS: Urinary aluminium concentrations showed significant changes after exposure compared to preexposure levels (mean t(1) (0 h) 13.5 µg/L; mean t(2) (6 h) 23.5 µg/L). Plasma results showed the same pattern but pre-post comparison did not reach significance. CONCLUSIONS: We were able to detect a significant increase of the internal aluminium burden of a single MIG aluminium welding process in urine, while plasma failed significance. Biphasic elimination kinetic can be observed. The German BAT of 60 µg/g creatinine was not exceeded, and urinary aluminium returned nearly to baseline concentrations after 7 days.

Effects of hyperbaric gases on membrane nanostructure and function in neurons.

This mini-review summarizes current ideas of how hyperbaric gases (>1-10 atmospheres absolute) affect neuronal mechanisms of excitability through molecular interaction with membrane components. The dynamic nature of the lipid bilayer, its resident proteins, and the underlying cytoskeleton make each respective nanostructure a potential target for modulation by hyperbaric gases. Depending on the composition of the gas mixture, the relative concentrations of O(2) and inert gas, and total barometric pressure, the net effect of a particular gas on the cell membrane will be determined by the gas' 1) lipid solubility, 2) ability to oxidize lipids and proteins (O(2)), and 3) capacity, in the compressed state, to generate localized shear and strain forces between various nanostructures. A change in the properties of any one membrane component is anticipated to change conductance of membrane-spanning ion channels and thus neuronal function.

[Thyroid cancer after Chernobyl: is iodine 131 the only culprit ? Impact on clinical practice]. / Le cancer de la thyroïde après Tchernobyl: l'iode 131 seul responsable? Conséquences en termes de pratique médicale.

The large increase in the incidence of thyroid cancer among children who were mainly less than five years old at the time of the Chernobyl accident is still a major preoccupation for endocrinologists and nuclear physicians. Epidemiological studies have focused solely on iodine 131. However, past knowledge on thyroid irradiation (medical use of iodine 131, radioactive fallout on Marshall islands and the Nevada, and Hanford site releases) as well as number of recent works (about low-dose irradiation), raise question on the role of other factors. It is here shown that post-Chernobyl thyroid irradiation is complex and that all factors (iodine 131, but also short lived isotopes of iodine and external irradiation) should be considered. Finally, one need to think about some of the present medical uses of iodine 131, and especially to the treatment of hyperthyroidism in young subjects.