Structural and immunological characterization of a new nucleotidyltransferase-like antigen from Paracoccidioides brasiliensis.

Pb27 antigen is an interesting alternative to immunological diagnosis of Paracoccidioidomycosis (PCM) and has demonstrated to be protective in experimental PCM. Its tertiary structure and possible function remained unknown till now. To study Pb27 at the atomic level, the recombinant protein was expressed in Escherichia coli BL21(DE3), purified, and its three-dimensional structure was solved by X-ray crystallography. Based on this structure, we performed a residue correlation analysis and in silico ligand search assays to address a possible biological function to Pb27. We identified Pb27 as a member of the extensive nucleotidyltransferase superfamily. The protein has an αßαßαß topology with two domains (N- and C-terminal domains) and adopts a monomeric form as its biological unit in solution. Structural comparisons with similar members of the superfamily clearly indicate Pb27 C-terminal domain is singular and may play an important role in its biological function. Bioinformatics analysis suggested that Pb27 might bind to ATP and CTP. This suggestion is corroborated by the fact that a magnesium cation is coordinated by two aspartic acid residues present at the active site (between N- and C-terminal domains), as evidenced by X-ray diffraction data. Besides, NMR assays (1H-15N HSQC spectra) confirmed the binding of CTP to Pb27, demonstrating for the first time an interaction between a nucleotide and this protein. Moreover, we evaluated the reactivity of sera from patients with Paracoccidioides brasiliensis infection against the recombinant form of Pb27 and showed that it was recognized by sera from infected and treated patients. Predicted B and T cell epitopes were synthesized and further evaluated against sera of PCM patients, providing information of the most reactive peptides in Pb27 primary structure which interact with specific Pb27 antibodies.

Serum levels of sTNF-R1, sTNF-R2 and CXCL9 correlate with disease activity in adult type paracoccidioidomycosis.

Paracoccidioidomycosis (PCM) is the most common systemic mycosis in Latin America. A major problem in the management of PCM is to determine the best time to discontinue therapy due to the high relapse rate among patients. Soluble TNF receptors (sTNF-R) levels and chemokines are associated with disease activity in several infectious, inflammatory and autoimmune disorders. The aim of the present work was to evaluate levels of sTNF-R1, sTNF-R2 and chemokines in serum of patients with adult type of PCM, before and after antifungal therapy, and to correlate those levels to disease activity. Concentrations of sTNF-R1, sTNF-R2 and CXCL9 were higher in untreated patients and decreased progressively with treatment. The serum marker with the best accuracy to discriminate PCM cases from controls was sTNF-R2. sTNF-R1 did not drop to control levels before 36 months of treatment. CCL2 and CCL3 levels were low at baseline in PCM patients, raised significantly after 12 months of treatment and diminished thereafter. CCL24 levels were higher after 36 months of antifungal therapy in PCM patients. CCL11 levels were not statistically different from control subjects. sTNF-R1, sTNF-R2 and CXCL9 may be useful as laboratory parameters to assess disease activity in PCM patients.

Risk factors for nosocomial infection in a neonatal intensive care unit.

OBJECTIVE: To determine risk factors for nosocomial infection in a neonatal intensive care unit (NICU). DESIGN: A prospective, open cohort study. SETTING: A 22-bed NICU. PATIENTS: Neonates admitted to a single NICU during 1994-1998 were included in the study. Outcome variables included central venous catheter (CVC)-associated primary bloodstream infection (BSI), non-CVC-associated primary BSI, pneumonia, and overall nosocomial infection. Independent variables included birth weight, use of mechanical ventilation (MV), duration of MV, use of a CVC, duration of CVC use, duration of NICU stay, gestational age, congenital malformation, maximum (ie, worst) base excess, and maximum and minimum fraction of inspired oxygen (FIO(2)) for maintaining appropriate blood saturation levels during the first 12 hours after NICU admission. RESULTS: A total of 1051 neonates were admitted to the NICU. Overall, 358 NIs were diagnosed. Non-CVC-associated primary BSI was the most frequent nosocomial infection (in 195 neonates [54.5%]), followed by pneumonia (46 [12.8%]), and CVC-associated primary BSI (35 [9.8%]). The mortality rate was 16%. In the final logistic regression model, the following 5 risk factors were found to be predictive of nosocomial infection development: use of MV, longer duration of MV, longer duration of CVC use, longer duration of NICU stay, and low maximum appropriate Fio(2). CONCLUSION: Invasive device use and duration of use continue to greatly influence the development of nosocomial infection in NICUs. In our cohort, birth weight showed no influence on the development of nosocomial infection. Low maximum Fio(2) influenced the occurrence of overall nosocomial infection.

Tétano no Brasil: doença do idoso? / Tetanus in Brazil: a disease of the elderly?

No Brasil, a distribuiçäo etária do tétano é pouco estudada. Neste trabalho foi analisada a evoluçäo histórica do coeficiente de mortalidade por tétano no Brasil, entre 1980 e 1991, e estabelecida a distribuiçäo dos casos pela faixa etária, tendo por base o Sistema de Informaçöes de Mortalidade. Os coeficientes de mortalidade por faixa etária foram calculados conforme os dados fornecidos pela FUNASA-CENEPI, DATASUS e IBGE. Utilizou-se o teste qui-quadrado para comparar os coeficientes de mortalidade para as diversas faixas etárias, por ano e regiäo do país. Houve declínio dos coeficientes de mortalidade em todas as faixas etárias, exceto nos idosos. Nas regiöes Norte e Sul houve aumento do coeficiente de mortalidade nos idosos. No Brasil, o tétano vem apresentando comportamento epidemiológico semelhante ao observado oos países desenvolvidos, onde os idosos representam o principal grupo de risco para adoecer e morrer da doença

Pulmonary involvement in Schistosomiasis mansoni

The post-treatment pulmonary alterations were evaluated in patients (Study 1) and in mice (Study 2) infected with Schistosoma mansoni. Study 1: the patients were examined pre and post-treatment (with ora oxamniquine) and the following exams were performed: sputum for eosinophils and chest x-ray. Study 2: four groups of mice (total = 64) were studied; Group I (infected and treated with oxamniquine); II (infected and not treated); III (not infected and treated) and IV (not infected and not treated). All were x-rayed to check for pulmonary abnormalities pre and post-treatment and lung specimens were studied by optical microscopy and immunofluorescence. We have found abnormalities in the parameters checked in both studies and the results suggest an immunological reaction, probably due to deposition of immune complexes in the lungs, with subsequent activation of the complement system. The experimental study showed that the alterations are not dependent of the presence of eggs and/or worms of S. mansoni in the lungs, thus corroborating the hypothesis of deposition of circulating material.