The hypothalamic-pituitary-adrenal and sympathetic-adrenomedullary axes are the main systems activated in response to stress. Alterations in salivary components and flow rate have been associated with oral health problems and psychological stress. Objectives: The aim of the present study was to investigate the influence of psychological stress on salivary flow, total protein concentration and IgG, IgM and IgA concentrations. Methods: Thirty-eight medical students, average age of 21.4 ± 2.1 years and enrolled in the 2nd to 5th years of their course, took part voluntarily in the study which involved two different periods: the first after vacations and the second during the final exams (a gap of 4 months). An Oral Health Questionnaire and the Lipp Inventory of Stress Symptoms for Adults (ISSL) were applied during both these periods. The flow rate, total protein concentration and immunoglobulin titers of saliva samples, collected after stimulation and stored in a container with protease inhibitor, were measured. Results: Analysis of the ISSL showed that 42.1% (n = 16) of the students had stress during the post-vacation period, and 44.7% (n = 17) during the final exams. The students’ salivary flow rate was significantly lower during the latter period than during the post-vacation period (p < 0.0001), regardless of the presence or absence of psychological stress as measured by the ISSL. There was a reduction in salivary flow rate and a consequent reduction in total protein concentration during the exam period (p = 0.0058). However, during both periods of the study there was no significant difference in total salivary protein concentration between the groups of students with or without psychological stress according to the ISSL (p > 0.05). IgG predominated over IgA and IgM (p < 0.001) during both study periods, regardless of the presence or absence of psychological stress. The study period and the presence of stress influenced the secretion of salivary immunoglobulins. IgM titers during the post-vacation period (p = 0.0044), and IgA (p = 0.028), IgG (p = 0.022) and IgM (p = 0.0075) titers during the final exams were higher in students with symptoms of psychological stress. Conclusions: Although the immunoglobulin titers were high, there was a reduction in the students’ salivary flow rates and a consequent reduction in total protein concentrations.

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Purpose:To evaluate the importance of spleen in malaric infection in murino model, comparing the parasitemia and the titles of imunoglobulins in the different groups. Methods: It was used female mice non-isogenic, in inoculated with Plasmodium berghei, cepa ANKA, intraperitoneally. The parasitemia was analyzed in 23rd, 25th, 27th and 32nd day of the experiment, being the stained blood' exam colored by Giemsa. The titles of the total serum immunoglobulins IgM and IgG were analyzed by Dot-ELISA technique, at 6th, 22nd and 32nd day, when the animals were sacrificed. Results: The parasitemia was gradual in all the inoculated groups. In the end of the experiment, the animals with partial parasitemia present superior parasitemia, but next to the non-splenectomized, while the asplenics present difference bigger than the double. The levels of total serum IgM and IgG didin´t have significant changes with the removal partial or total splenic. Conclusion: The techniques conservatives in splenic trauma are possible and necessary. The importance of remaining spleen in the clearance of red blood cells parasitized by Plasmodium berghei showed being efficient, in order to avoid serious complications resulting of the malaria in mice. Key words: Splenectomy. Malaria. Sepsis. Infection. Mice. RESUMOObjetivo: Avaliar a importância do baço na infecção malárica em modelo murino, comparando a parasitemia e os títulos das imunoglobulinas nos diferentes grupos. Métodos: Utilizaram-se camundongos fêmeos não isogênicos, inoculados com Plasmodium berghei, cepa ANKA, intraperitoneal. A parasitemia foi analisada no 23°, 25°, 27º e 32° dia do experimento, sendo o exame do esfregaço sangüíneo, corado pelo Giemsa. As titulações das imunoglobulinas totais séricas IgM e IgG foram realizadas pela técnica Dot-ELISA, no 6°, 22° e no 32° dia, quando os animais foram sacrificados. Resultados: A parasitemia foi progressiva em todos os grupos inoculados. Ao final do experimento, os animais com esplenectomia parcial apresentaram parasitemia superior, porém próximos as dos não esplenectomizados, enquanto que os asplênicos apresentaram diferença superior a 100%. Os níveis de IgM e IgG totais séricos não foram alterados significativamente com a remoção parcial ou total esplênica. Conclusão: As técnicas conservadoras no trauma esplênico são possíveis e necessárias. A importância do remanescente esplênico no clearence das hemácias infectadas pelo Plasmodium berghei demonstrou ser eficiente, de modo a evitar sérias complicações decorrentes da malária em camundongos. Descritores: Esplenectomia. Malária. Sepse. Infecção. Camundongos. ¹Research performed at