Prevalence of intestinal parasites versus knowledge, attitudes, and practices of inhabitants of low-income communities of Campos dos Goytacazes, Rio de Janeiro State, Brazil.

Intestinal parasites are the causative agents of common infections responsible for significant public health problems in developing countries and generally linked to lack of sanitation, safe water, and improper hygiene. More than two billion people throughout the world live with unrelenting illness due to intestinal parasitic infections (IPIs). The purposes of this study are to assess knowledge, attitudes, and practices on IPIs and investigate the relationship with prevalence of intestinal parasites among a low-income group of inhabitants from two communities of the Travessão District area, Campos dos Goytacazes, north of Rio de Janeiro State, Brazil. The two communities are known as "Parque Santuário," which is an urban slum with miserable living conditions, and "Arraial," where the socioeconomic and educational levels are better, neither having a sanitary infrastructure with an excreta collection system. Questionnaires revealed that both communities had local and specific codification to denominate the intestinal parasites and present correct knowledge on the theme but ignored some aspects of IPI transmission, with the Arraial population being better informed (p < 0.05). The overall prevalence of IPIs in Parque Santuário (49.7%) was greater than in Arraial (27.2%) (p < 0.001; prevalence ratio/95% confidence interval 1.83/1.50-2.23). This study reports the real IPI situation in the Travessão District and also reinforces the need to continue the investigation on the impact of combined prophylactic methods, educational measures, and socioeconomic and sanitary improvements by governmental authorities and the local popular organization.

Cytochemical characterization of microvillar and perimicrovillar membranes in the posterior midgut epithelium of Rhodnius prolixus.

Perimicrovillar membranes (PMM) are structures present on the surface of midgut epithelial cells of the hematophagous insect, Rhodnius prolixus. They cover the microvilli and are especially evident 10 days after blood meal, providing the compartmentalization of the enzymatic processes in the intestinal microenvironment. Using an enzyme cytochemical approach, Mg2+-ATPase and ouabain-sensitive Na+K+-ATPase activities were observed in the plasma (or microvillar) membrane (MM) of midgut cells and in the PMM. In contrast, alkaline phosphatase was only detected in MM. Using cationized ferritin and colloidal iron hydroxide particles, anionic sites were found only on the luminal surface of the PMM. Using fluorescein isothiocyanate (FITC)-labeled lectins, residues of alpha-d-galactose, mannose, N-acetyl-neuraminic acid, N-acetyl-d-galactosamine and N-acetyl-galactosamine-alpha-1,3-galactose were detected on the apical surface of posterior midgut epithelial cells. On the other hand, using FITC-labeled neoglycoproteins (NGP) it was possible to detect the presence of carbohydrate binding molecules (CBM) recognizing N-acetyl-d-galactosamine, alpha-d-mannose, alpha-l-fucose and alpha-d-glucose in the posterior midgut epithelium. The use of digitonin showed the presence of sterols in the MM and PMM. These results have led the authors to suggest that for some components the PMM resembles the MM lining the midgut cells of R. prolixus, composing a system which covers the microvilli and stretches to the luminal space.

Ca(2+) sequestering in the early-branching amitochondriate protozoan Tritrichomonas foetus: an important role of the Golgi complex and its Ca(2+)-ATPase.

Total membrane vesicles isolated from Tritrichomonas foetus showed an ATP-dependent Ca(2+) uptake, which was not sensitive to 10 microM protonophore FCCP but was blocked by orthovanadate, the inhibitor of P-type ATPases (I(50)=130 microM), and by the Ca(2+)/H(+) exchanger, A-23187. The Ca(2+) uptake was prevented also by thapsigargin, an inhibitor of the SERCA Ca(2+)-ATPases. The sensitivity of the Ca(2+) uptake by the protozoan membrane vesicles to thapsigargin was similar to that of Ca(2+)-ATPase from rabbit muscle sarcoplasmic reticulum. Fractionation of the total membrane vesicles in sucrose density gradient revealed a considerable peak of Ca(2+) transport activity that co-migrated with the Golgi marker guanosine diphosphatase (GDPase). Electron microscopy confirmed that membrane fractions of the peak were enriched with the Golgi membranes. The Golgi Ca(2+)-ATPase contributed to the Ca(2+) uptake by all membrane vesicles 80-85%. We conclude that: (i) the Golgi and/or Golgi-like vesicles form the main Ca(2+) store compartment in T. foetus; (ii) Ca(2+) ATPase is responsible for the Ca(2+) sequestering in this protozoan, while Ca(2+)/H(+) antiporter is not involved in the process; (iii) the Golgi pump of this ancient eukaryotic microorganism appears to be similar to the enzymes of the SERCA family by its sensitivity to thapsigargin.