Análise TG-ROC de testes de imunofluorescência no diagnóstico de leishmaniose visceral canina

OBJETIVO: Analisar a acurácia do diagnóstico de dois protocolos de imunofluorescência indireta para leishmaniose visceral canina. MÉTODOS: Cães provenientes de inquérito soroepidemiológico realizado em área endêmica nos municípios de Araçatuba e de Andradina, na região noroeste do estado de São Paulo, em 2003, e área não endêmica da região metropolitana de São Paulo, foram utilizados para avaliar comparativamente dois protocolos da reação de imunofluorescência indireta (RIFI) para leishmaniose: um utilizando antígeno heterólogo Leishmania major (RIFI-BM) e outro utilizando antígeno homólogo Leishmania chagasi (RIFI-CH). Para estimar acurácia utilizou-se a análise two-graph receiver operating characteristic (TG-ROC). A análise TG-ROC comparou as leituras da diluição 1:20 do antígeno homólogo (RIFI-CH), consideradas como teste referência, com as diluições da RIFI-BM (antígeno heterólogo). RESULTADOS: A diluição 1:20 do teste RIFI-CH apresentou o melhor coeficiente de contingência (0,755) e a maior força de associação entre as duas variáveis estudadas (qui-quadrado=124,3), sendo considerada a diluição-referência do teste nas comparações com as diferentes diluições do teste RIFI-BM. Os melhores resultados do RIFI-BM foram obtidos na diluição 1:40, com melhor coeficiente de contingência (0,680) e maior força de associação (qui-quadrado=80,8). Com a mudança do ponto de corte sugerido nesta análise para a diluição 1:40 da RIFI-BM, o valor do parâmetro especificidade aumentou de 57,5% para 97,7%, embora a diluição 1:80 tivesse apresentado a melhor estimativa para sensibilidade (80,2%) com o novo ponto de corte. CONCLUSÕES: A análise TG-ROC pode fornecer importantes informações sobre os testes de diagnósticos, além de apresentar sugestões sobre pontos de cortes que podem melhorar as estimativas de sensibilidade e especificidade do teste, e avaliá-los a luz do melhor custo-benefício.

Trap-nesting bees (Hymenoptera: Apoidea) in forest fragments of the State of Sao Paulo, Brazil

We studied the community ecology of trap-nesting bees in two forest fragments of the State of Sao Paulo, Brazil, during two years, utilizing bamboo canes and tubes made of black cardboard as trap nests. The traps were inspected once a month with an otoscope. One hundred and fifteen nests were obtained at Estacao Ecologica de Paulo de Faria, Paulo de Faria (EEPF). These included nine species belonging to five genera and two families. At Santa Cecilia Farm (SCF), 12 species belonging to seven genera and three families built 392 nests. Natural enemies reared from nests of both areas included Hymenoptera, Diptera and Coleoptera. Species richness was similar between the areas but the communities differed considerably in species composition. The higher diversity found at EEPF was due to more even distribution of the species. No difference was observed between the numbers of nests built in each year in each area. Although the species richness was lower in the cool/dry season of both years at SCF, and in the first year at EEPF, the nesting frequencies did not differ between seasons for both the overall community but for each of the most abundant species. No annual fluctuation in the frequencies of nesting was observed. As temperature and precipitation were not found to be significantly different between the two years of study in each area, we concluded that climatic stability resulted in population stability.

Vibration-enhanced posture stabilization achieved by tactile supplementation: May blind individuals get extra benefits?

Diminished balance ability poses a serious health risk due to the increased likelihood of falling, and impaired postural stability is significantly associated with blindness and poor vision. Noise stimulation (by improving the detection of sub-threshold somatosensory information) and tactile supplementation (i.e. additional haptic information provided by an external contact surface) have been shown to improve the performance of the postural control system. Moreover, vibratory noise added to the source of tactile supplementation (e.g. applied to a surface that the fingertip touches) has been shown to enhance balance stability more effectively than tactile supplementation alone. In view of the above findings, in addition to the well established consensus that blind subjects show superior abilities in the use of tactile information, we hypothesized that blind subjects may take extra benefits from the vibratory noise added to the tactile supplementation and hence show greater improvements in postural stability than those observed for sighted subjects. If confirmed, this hypothesis may lay the foundation for the development of noise-based assistive devices (e.g. canes, walking sticks) for improving somatosensation and hence prevent falls in blind individuals. (C) 2011 Elsevier Ltd. All rights reserved.

Cellular prion protein (PrP(C)) and superoxide dismutase (SOD) in vascular cells under oxidative stress

The PrP(C) is expressed in several cell types but its physiological function is unknown. Some studies associate the PrP(C) with copper metabolism and the antioxidant activity of SOD. Our hypothesis was that changes in PrP(C) expression lead to abnormal copper regulation and induce SOD downregulation in the vascular wall. Objectives: to study whether the PrP(C) expression undergoes induction by agents that trigger endoplasmic reticulum stress (ERS) and, in this context, to evaluate the SOD activity. Methods: To trigger ERS, in vitro, rabbit aortic smooth muscle cells were challenged for 4, 8 and 18 hours, with angiotensin-II, tunicamycin and 7-ketocholesterol. For in vivo studies rabbit aortic arteries were subjected to injury by balloon catheter. Results: In vitro baseline SOD activity, determined through inhibition of cytochrome-c reduction, was 13.9 +/- 1.2 U/mg protein, angiotensin-II exposed for 8 hours produced an increase in SOD activity, and cellular copper concentration was about 9 times greater only under these conditions. Western blotting analysis for SOD isoenzymes showed an expression profile that was not correlated with the enzymatic activity. PrP(C) expression decreased after exposure to all agents after different incubation periods. RT-PCR assay showed increased mRNA expression for PrP(C) only in cells stimulated for 8 hours with the different stressors. The PrP(C) mRNA expression in rabbit aortic artery fragments, subjected to balloon catheter injury, showed a pronounced increase immediately after overdistension. The results obtained indicated a PrP(C) protection factor during the early part of the ERS exposure period, but did not demonstrate a SOD-like profile for the PrP(C). (C) 2009 Elsevier GmbH. All rights reserved.

Ehrlichia canis in dogs attended in a veterinary hospital from Botucatu, Sao Paulo State, Brazil

This study investigated the etiology of canine ehrlichiosis and possible clinical and epidemiological data associated with the infection in 70 dogs suspect of ehrlichiosis attended at the Veterinary Hospital of the Sao Paulo State University in Botucatu city during 2001 and 2002. Dogs were evaluated by clinical-epidemiological and hematological data and molecular analysis by partial amplification and DNA sequencing of the ehrlichial dsb gene. E. canes DNA was amplified and sequenced in 28 (40.0%) dogs. Dogs younger than 12 months old showed significantly higher infection rates (65.0%; P < 0.05). Diarrhea, apathy, and anorexia were the major clinical signs observed in 55.2% (P = 0.05), 47.0% (P > 0.05), and 42.4% (P > 0.05) of the PCR-positive dogs, respectively. Twenty-five anemic (<5.5 x 10(6) RBC.mu L(-1)), and 8 leukopenic (<5.5 x 10(3) WBC.mu L(-1)) dogs were PCR-positive (P > 0.05). All 28 PCR-positive dogs showed thrombocytopenia (<175 x 10(3) platelets.mu L(-1)) and revealed statistical significance (P < 0.05). E. canis was the only Ehrlichia species found in dogs in the studied region, with higher infection rates in younger dogs, and statistically associated with thrombocytopenia.