Search

Background: Healthcare workers may be exposed to a variety of biological hazards. Although many studies have shown that some immunological alterations were related to work stress and sleep disorders, few studies investigated effects of shiftwork on the immunological system., Objectives: The aim of the study was to compare the immune status of a group of nurses on shiftwork with that of nurses working only day shifts., Methods: A total of 138 nurses were evaluated at baseline and after a year of follow-up, via tests for perceived stress, daytime sleepiness, number of lymphocytes and subpopulation of CD3+, CD4+, CD8+-CD57+, CD19+ and CD56+, cytotoxic activity and lympho-prolferative response of NK cells, serum concentrations of IL-1beta, IL-6, INFgamma and TNFalpha., Results and Conclusion: No significant alterations of any of the studied parameters were found both at baseline and after a year of follow-up. The biological hazards for nurses do not seem to be increased by shiftwork.

Mercury (Hg) exposure makes happen disease to humans and animals spreading in all body compartments, especially in liver and kidney. In these ones, copper, zinc, manganese and iron were investigated to assess perturbation of essential metals' homeostasis due to Hg chronic intoxication. Because L-arginine, is able to induce beneficial influence on immunologic functions on mice intoxicated with Hg, we also studied the efficiency of detoxification process before and after treatment with this aminoacid. Adding L-arginine to diet of the intoxicated mice we achieved a good restoration to normal homeostatic conditions.

Occupational or environmental exposure to various metals affects human health. In particular, mercury is known to affect the immune system adversely. Metallothioneins (MTs) are low molecular weight, cysteine-rich, intracellular proteins, with high affinity for bivalent metals of which they regulate intracellular concentrations, thereby being playing a fundamental role in metal homeostasis. MTs protect cells from stress, inflammation and free radical damage and are involved in zinc homeostasis. Zinc has an important role in the immune system because it is indispensable for the activation andfunctioning of the thymic hormone, thymulin, which in turn is involved in T-lymphocyte differentiation and maturation. MTs participate in the detoxification process following acute poisoning, and are expressed in the various tissues, as well as in chronic intoxication, where continuous stress and the persistent inflammatory state induce their over-expression. The present study was undertaken to gain insights into the potential mechanisms acting on the immune system/altering the immune status in the presence of low mercury concentrations. To do this, the genic expression of MT-I and the amount of active thymulin produced by thymic endothelial cells were studied in mice exposed to different doses of mercury.

Occupational exposure at low doses of lead induces a significant increase of TNF-alpha plasma levels. Recently has been showed the crucial role on atherosclerosis origin of this pro-inflammatory cytokine. It is assumable a contribution of lead in atherosclerosis course in exposed subjects.