Morphological and quantitative study of ganglionated plexus of Calomys callosus trachea

Calomys callosus is a wild, native forest rodent found in South America. In Brazil, this species has been reported to harbour the parasitic protozoan Trypanosoma cruzi. The ganglionated plexus of this species was studied using whole-mount preparations of trachea that were stained using histological and histochemical methods. The histological methods were used to determine the position of the ganglia with respect to the trachea muscle and to determine the presence of elastic and collagen fibers. The histochemical method of NADH-diaphorase was used for morphometric evaluations of the plexus. The tracheal plexus lies exclusively over the muscular part of the organ, dorsal to the muscle itself. It varies in pattern and extent between animals. The average number of neurons was 279 and the cellular profile area ranged from 38.37 mu m(2) to 805.89 mu m(2). Acetylcholinesterase (AChE) histochemistry verified that both ganglia and single neurons lie along nerve trunks and are reciprocally interconnected with the plexus. Intensely AChE-reactive neurons were found to be intermingled with poorly reactive ones. Two longitudinal AChE-positive nerve trunks were also observed and there was a diverse number of ganglia along the intricate network of nerves interconnecting the trunks. A ganglion capsule of collagen and elastic fibers surrounding the neurons was observed. Under polarized light, the capsule appeared to be formed by Type I collagen fibers. (C) 2008 Elsevier B.V. All rights reserved.

Genetic typing of Trypanosoma cruzi isolates from different hosts and geographical areas of western Venezuela

A total of 72 Trypanosoma cruzi isolates from different hosts and geographical regions of western Venezuela, where Chagas disease is endemic, were typed using ribosomal and mini-exon gene markers. The isolates were obtained from wild, peridomestic and domestic sources including triatomine-bugs, human acute chagasic patients and other mammals. Results showed that T. cruzi two major phylogenetic lineages, T. cruzi I and T. cruzi II were present. However, a remarkable predominance of T. cruzi I (96%) over T. cruzi II (4%) was observed. The present results suggest that in western Venezuela circulation of both T. cruzi I and T. cruzi II isolates is independent from the source of isolation and the geographical area where they occur, with predominance of T. cruzi I. The epidemiological significance of the present results is discussed.

Inconclusive results in conventional serological screening for Chagas` disease in blood banks: evaluation of cellular and humoral response

To find the most reliable screening method for Trypanosoma cruzi infection in blood banks. Epidemiological data, lymphoproliferation assay, parasitological, conventional serological tests: immunofluorescence, haemagglutination, ELISA with epimastigote and trypomastigote antigens and reference serological tests: trypomastigote excreted-secreted antigens (TESA) blot and chemiluminescent ELISA assay with mucine from trypomastigote forms were applied to individuals with inconclusive serology, non-chagasic individuals and chronic chagasic patients. TESA blot had the best performance when used as a single test in all the groups. In the inconclusive group 20.5% of individuals were positive for TESA blot, 23.3% for either lymphoproliferation or TESA blot, and 17.8% for lymphoproliferation only. Positive lymphoproliferation without detectable antibodies was observed in 5.47% of all inconclusive serology cases. Analysis of six parameters (three serological assays, at least one parasitological test, one lymphoproliferation assay and epidemiological data) in the inconclusive group showed that diagnosis of Chagas` disease was probable in 15 patients who were positive by two or more serological tests or for whom three of those six parameters were positive. TESA blot is a good confirmatory test for Chagas` disease in the inconclusive group. Although lymphoproliferation suggests the diagnosis of Chagas` disease in the absence of antibodies when associated with a high epidemiological risk of acquiring Chagas` disease, the data from this study and the characteristics of the lymphoproliferation assay (which is both laborious and time-consuming) do not support its use as a confirmatory test in blood-bank screening. However, our findings underscore the need to develop alternative methods that are not based on antibody detection to improve the diagnosis when serological tests are inconclusive.

Antioxidant therapy attenuates oxidative insult caused by benzonidazole in chronic Chagas` heart disease

Chronic chagasic cardiac patients are exposed to oxidative stress that apparently contributes to disease progression. Benznidazole (BZN) is the main drug used for the treatment of chagasic patients and its action involves the generation of reactive species. 41 patients with Chagas` heart disease were selected and biomarkers of oxidative stress were measured before and after 2 months of BZN treatment (5 mg/kg/day) and the subsequent antioxidant supplementation with vitamin E (800 UI/day) and C (500 mg/day) during 6 months. Patients were classified according to the modified Los Andes clinical hemodynamic classification in groups IA, IB, II and III, and the activity of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione S-transferase (GST) and glutathione reductase (GR), as well as the contents of reduced glutathione (GSH), thiobarbituric acid reactive species (TBARS), protein carbonyl (PC), vitamin E and C and nitric oxide (NO), myeloperoxidase (MPO) and adenosine deaminase (ADA) activities were measured in their blood. Excepting in group III, after BZN treatment SOD, CAT, GPx and GST activities as well as PC levels were enhanced while vitamin E levels were decreased in these groups. After antioxidant supplementation the activities of SOD, GPx and GR were decreased whereas PC, TBARS, NO, and GSH levels were decreased. In conclusion, BZN treatment promoted an oxidative insult in such patients while the antioxidant supplementation was able to attenuate this effect by increasing vitamin E levels, decreasing PC and TBARS levels, inhibiting SOD, GPx and GR activities as well as inflammatory markers, mainly in stages with less cardiac involvement. (C) 2009 Elsevier Ireland Ltd. All rights reserved.