RESUMO Neste trabalho será investigado o comportamento de escoamentos de fluidos newtonianos e não-newtonianos em microcanais. O problema não-newtoniano, consiste em resolver as equações que regem o movimento para o caso de um escoamento de fluidos cujas propriedades reológicas possam ser estudadas pelo modelo constitutivo de Phan-Thien-Tanner, como por exemplo os materiais poliméricos. Uma das características interessantes de alguns destes materiais é que eles podem ser misturados com solventes apropriados, como uma solução eletrolítica, e o resultado é que este fluido como um todo passa a ter propriedades elétricas. Assim, além das propriedades viscoelásticas, será investigada a eletrocinética do escoamento, que é diretamente influenciado pela aplicação de um campo elétrico externo. Em particular o fenômeno de eletroosmose será estudado por meio de simulações numéricas em canais planos. O movimento das cargas na solução é descrito pelas equações de Poisson-Nernst-Planck e para resolver numericamente este problema será aplicado o método das diferenças finitas generalizadas. O código para as simulações de escoamentos eletroosmóticas foi implementado como uma parte do sistema chamado HiG-Fow.

ABSTRACT In this work the behavior of newtonian and non-Newtonian fluids in microchannels will be investigated. The non-Newtonian problem consists in solving the governing equations of the movement take into account a fluid flow whose rheological properties can be studied by the Phan-Thien-Tanner constitutive model, for example the polymeric materials. One of the interesting features of these materials is that they can be mixed with appropriate solvents, such as an electrolyte solution, and the resulting fluid has electrical properties. Thus, in addition to the viscoelastic properties, the electrokinetics properties of the flow will be investigated, which is directly influenced by the application of an external electric field. In particular the phenomenon of electro-osmosis will be studied through numerical simulations in flat channels. The motion of the charges in the solution is described by the Poisson-Nernst-Planck equations and to solve numerically this problem will be applied the generalized finite difference method. The code for the simulations of electroosmotic flows was implemented as a part of the HiG-Fow system.

Paracoccidioides brasiliensis and P. lutzii are fungi that cause paracoccidioidomycosis (PCM), the most prevalent systemic mycosis in South America. For serological diagnosis, although 43-kDa glycoprotein (gp43) is regarded as highly specific for PCM, the occurrence of false negative reactions in sera from patients infected with P. lutzii suggests that preparation with only one antigen is not recommended. Heat shock proteins are feasible alternatives as a second antigen because they are often highly immunogenic. In this study, we evaluated the usefulness of recombinant 60-kDa heat shock protein from P. brasiliensis (rPbHsp60) for the serological diagnosis of PCM. Using western blotting assay, we observed that 77.3% of the sera from PCM patients were positive to rPbHsp60, with 90.9% positivity to recombinant gp43 (rgp43). More importantly, sera from healthy subjects had 27% positivity to rPbHsp60 and none to rgp43. When rPbHsp60 was used in ELISA, we did not observe significant differences between the reactions with sera from PCM patients and healthy subjects, while the difference was clearly evident when the antigen was rgp43. Furthermore, rPbHsp60 was recognized by sera from patients with histoplasmosis, aspergillosis, sporotrichosis or tuberculosis in an ELISA test. These results show that rPbHsp60 is not a good antigen for PCM diagnosis.

In DNA vaccines, the gene of interest is cloned into a bacterial plasmid that is engineered to induce protein production for long periods in eukaryotic cells. Previous research has shown that the intramuscular immunization of BALB/c mice with a naked plasmid DNA fragment encoding the Mycobacterium leprae 65-kDa heat-shock protein (pcDNA3-Hsp65) induces protection against M. tuberculosis challenge. A key stage in the protective immune response after immunization is the generation of memory T cells. Previously, we have shown that B cells capture plasmid DNA-Hsp65 and thereby modulate the formation of CD8+ memory T cells after M. tuberculosis challenge in mice. Therefore, clarifying how B cells act as part of the protective immune response after DNA immunization is important for the development of more-effective vaccines. The aim of this study was to investigate the mechanisms by which B cells modulate memory T cells after DNA-Hsp65 immunization. C57BL/6 and BKO mice were injected three times, at 15-day intervals, with 100 µg naked pcDNA-Hsp65 per mouse. Thirty days after immunization, the percentages of effector memory T (TEM) cells (CD4+ and CD8+/CD44high/CD62Llow) and memory CD8+ T cells (CD8+/CD44high/CD62Llow/CD127+) were measured with flow cytometry. Interferon γ, interleukin 12 (IL-12), and IL-10 mRNAs were also quantified in whole spleen cells and purified B cells (CD43−) with real-time qPCR. Our data suggest that a B-cell subpopulation expressing IL-10 downregulated proinflammatory cytokine expression in the spleen, increasing the survival of CD4+ TEM cells and CD8+ TEM/CD127+ cells.

Influenza vaccination of elderly people is efficacious and cost effective for the prevention of influenza and its complications. Some studies have pointed out low immunogenicity in this group. Health status has been poorly investigated as a risk factor that may influence the immune response to influenza vaccine. We established an immunization response study of a highly-matched elderly population in a nursing home. One-hundred-twenty subjects of Ashkenazian origin had their vaccine-induced antibody response assessed. Good response was obtained in 30.8% (37/120), and 31.7% (38/120) did not react. A lack of good response was found to be associated with dementia (P=0.016) in a multivariate analysis. In addition to dementia, malnutrition was frequently observed among poor responders, suggesting that these factors should be considered in vaccination studies. Chemoprophylaxis in addition to vaccination for elderly presenting dementia should be considered, particularly for those people living nursing homes.

It is currently recommended that antiretroviral prophylaxis to prevent mother-to-child transmission (MTCT) of HIV be initiated at 14 weeks of gestation. However, the relevance of early-gestation HIV viral load level for intrauterine MTCT is unknown. The objective of this study was to determine the relationship between prenatal maternal viral load and intrauterine MTCT. Records of HIV-infected pregnant women in two centers in Brazil, from 1999 to 2004 were analyzed. Three pregnancy periods were considered: earlier than 14 weeks, 14 to 27 6/7 weeks, and 28 weeks of gestation or more. Peripartum HIV exposure was also computed. Maximum viral load in each period was the measure of HIV exposure. Four hundred fifty-seven HIV-infected pregnant women were evaluated, but 53 were excluded. The MTCT rate was 0.49% (2/404-95% confidence interval (CI95) = 0.14-1.79%). Newborns were not breast-fed. Median viral load for the earlier-than-14-week period was 9,900 copies/mL (P25-75 1,000-50,775 copies/mL), 8,350 copies/mL (P25-75 707-42,000 copies/mL) for the 14 to 27 6/7-week period, and 435 copies/mL (P25-75 90-7,775 copies/mL) after the 28-week period. The peripartum median viral load was 400 copies/mL (P25-75 80-500 copies/mL). MTCT in mothers with VL > 1,000 copies/mL during the first 14 weeks (0.67%, 2/298) was not different from those with VL =1,000 copies/mL (0.0%, 0/96, P=1). Analogously, in the 14 to 27 6/7-week period, MTCT was similar in groups with VL higher (0.68%, 2/292) or lower (0%, 0/106) than 1,000 copies/mL (P=1). Regarding VL >1,000 copies/mL at 28-weeks-or-later and at peripartum periods, MTCT rates were 1.15% (2/173, P = 0.18) and 2.8% (2/71, P = 0.03), respectively. Intrauterine transmission does not seem to be influenced by HIV viremia during the first 28 weeks of pregnancy.

OBJETIVO: Desenvolver uma estratégia capaz de otimizar a indicação de endoscopia digestiva alta (esofagogastroduodenoscopia-EGD) em pacientes com dispepsia e sem sinal de alarme para doença orgânica, baseada em variáveis clínicas e sociais com maior valor em discriminar indivíduos com EGD com alteração de indivíduos com EGD normal. CASUÍSTICA E MÉTODO: 200 pacientes (idade: 16-76 anos) com dispepsia e sem evidência de doença orgânica, atendidos em nível primário, foram entrevistados com um questionário estruturado e submetidos a EGD. Análise de regressão logística múltipla identificou variáveis com maior valor em discriminar indivíduos com EGD com alteração de indivíduos com EGD normal, bem como indivíduos com EGD com úlcera péptica daqueles com EGD normal. RESULTADOS: As variáveis com maior valor em discriminar indivíduos com EGD com alteração daqueles com EGD normal foram: idade igual ou superior a 45 anos e sexo masculino. Para discriminar indivíduos com EGD com úlcera péptica daqueles com EGD normal, as variáveis foram: idade igual ou superior a 45 anos; sexo masculino; tabagismo; empachamento e absenteísmo. Um modelo prático foi desenvolvido, visando a apoiar a decisão de indicar ou não EGD, apresentando sensibilidade de 78,9%, especificidade de 51,7%, valor preditivo positivo (VPP) de 39,4% e preditivo negativo (VPN) de 86%, para a identificação de indivíduos com EGD com alteração; e sensibilidade de 84%, especificidade de 70%, VPP de 38% e VPN de 95%, para a identificação de indivíduos com EGD com úlcera péptica. CONCLUSÃO: Uma estratégia baseada em variáveis clínicas e sociais de pacientes com dispepsia poderia potencialmente diminuir o número de EGD desnecessárias.

BACKGROUND: Although dyspepsia is a highly prevalent complaint, only a small percentage of patients are found to have serious disease and to need full investigation. The selection of dyspeptic patients who really need upper gastrointestinal endoscopy (UGE) is crucial in order to avoid unnecessary costs and overload services. MATERIAL AND METHODS: 200 primary care patients (age range 16-76 years) with dyspepsia and without any evidence of organic disease were interviewed with a structured questionnaire, and afterwards they underwent UGE. Multiple logistic regression analysis identified variables that could discriminate individuals with abnormal UGE from individuals with normal UGE, as well as individuals with peptic ulcer from individuals with normal UGE. RESULTS: The variables to discriminate individuals with abnormal UGE from individuals with normal UGE were age 45 years or above, and male sex, whereas to discriminate individuals with peptic ulcer in UGE from individuals with normal UGE were age 45 years or above, male sex, smoking, fullness, and absenteeism. A practical model based on these variables was developed, showing sensitivity of 78,9%, specificity of 51,7%, positive predictive value (PPV) of 39,4 % and negative predictive value (NPV) of 86% for the detection of individuals with UGE abnormal; and sensitivity of 84%, specificity of 70%, PPV of 38% and NPV of 95% for the identification of individuals with UGE identifying peptic ulcer. CONCLUSIONS: A strategy based on a model containing clinical and social characteristics of dyspeptic patients could potentially decrease the number of unnecessary UGEs.