No abstract

The serum immunoglobulin (IgG, IgM and IgA) concentrations of 44 mercury-exposed workers were examined and compared with those of non-exposed, age- and sex-matched individuals. At the time of testing, the exposed population had a mean (+/- S.D.) mercury urinary concentration of 24.7 +/- 19.1 and in 40 of them urinary mercury levels were below the currently accepted limit of 50 micrograms/g creatinine. Increased IgG, IgA and IgM levels were found in the mercury-exposed individuals and in 16, a second evaluation was performed six months later. During the intervening six months, the level of hygiene was improved throughout the plant, and urinary mercury concentrations were determined monthly in each worker. Despite a significant reduction in mercury urinary concentrations, serum immunoglobulin levels did not return to the normal range. There was no correlation between the length or level of exposure and the immunoglobulin levels. Liver protein synthesis, as studied by factor V, prothrombin time, prealbumin and transaminase activity, was normal and liver injury, as evaluated by serum aspartate and alanine aminotransferase activities (AST and ALT, respectively), was not observed. No haematological abnormalities were noted. These results indicate that "safe" levels of mercury exposure may lead to humoral immunological stimulation.

In this study, we have investigated the effects of the unicellular-green-algae Chlorella vulgaris on the production of INF-gamma, IL-2, IL-4 and IL-10 in normal and Listeria monocytogenes infected mice. Our results demonstrated that in normal/non infected mice, CVE administration produced no effects in the levels of all cytokines studied. However, Listeria monocytogenes infection enhanced the production of INF-gamma and IL-2 at 48 and 72 h after the bacteria inoculation. Interestingly, the treatment with five consecutive doses of 50 mg/Kg/day of Chlorella vulgaris given previously to infection, led to further increases in INF-gamma and IL-2 levels at 48 and 72 h in relation to the presence of infection alone. No changes in IL-4 and IL-10 production were observed in Listeria monocytogenes and CVE treated/infected mice. These results are in accordance with the literature, which shows that CVE is a biological response modifier that enhances resistance to Listeria monocytogenes through augmentation of IL-2 and IFN-gamma.

Avaliação de mudanças na dependência da nicotina, motivação e sintomas de ansiedade e depressão em fumantes no processo inicial de redução ou cessação do tabagismo: estudo de seguimento de curto prazo Assessment of changes in nicotine dependence, motivation, and symptoms of anxiety and depression among smokers in the initial process of smoking reduction or cessation: a short-term follow-up study Abstract Introduction: The first days of a quit attempt represent an important challenge to long-term abstinence, especially because of the changes that take place over this period. Objective: To examine whether smokers who have recently changed their smoking behavior show changes in the intensity of nicotine dependence, motivational stage, or symptoms of anxiety and depression relative to smokers without recent changes in smoking behavior. Methods: Smokers attending a support group for smoking cessation in Porto Alegre, southern Brazil, were invited to participate. The program consisted of four weekly sessions. Smokers answered questionnaires covering intensity of nicotine dependence, stage of motivation, and symptoms of anxiety and depression at baseline and in the fourth week. Urine was collected at both time points, tested for cotinine concentration, and used to determine the final status of smokers. Results: Of the 54 smokers included in the study, 20 (37%) stopped smoking or decreased tobacco use. Both smokers who stopped or reduced tobacco use and those who did not change their behavior presented a decrease in nicotine dependence scores (p = 0.001). Conversely, only the smokers who changed behavior presented an increase in scores in the maintenance stage (p < 0.001). Conclusion: When modifying tobacco use, smokers face a difficult process, marked by several changes. A better understanding of these changes and their implications for treatment are discussed.

In this work we have investigated the changes in T-helper and T-suppressor cells and T-cell proliferative response to phytohemagglutinin (PHA) in mercury-exposed workers. The study group consisted of 33 workers from a mercury-producing plant with a mean age of 29 years and a mean exposure period of 19 months. At the time of testing, and for the three previous months, the exposed population had urinary mercury levels below the currently accepted limit of 50 micrograms/g creatinine. A reverse CD4+/CD8+ ratio was observed in the mercury-exposed individuals which was characterized by a reduction in the number of CD4+ lymphocytes. No changes were observed in the proliferative response of lymphocytes from exposed individuals to PHA. Similarly, no proliferative response was observed when lymphocytes from normal individuals were cultivated in the presence of serum from the exposed workers. We found no correlations between lymphocytes changes and urinary mercury concentrations, time of exposure or the age of the workers.