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Eur. J. Med. Chem. 2011. 01/2011; 46:3324-3330.
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European Journal of Pharmaceutical Sciences. 01/2010; 39(1-3):30-36.
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ABSTRACT: In the present paper, the acute and subchronical inflammatory processes of the vaginal epithelial were studied in mice experimentally infected with two Trichomonas vaginalis strains of different pathogenicity, by means of histological and immunological methods. There was an increase in the stratified epithelium layers as well as edema produced by the increase of vascularization in the propia submucosa and infiltration of leukocytes. The proliferation of the vaginal epithelium favors the settlement and persistence of the parasitic infection. All of the findings corresponded with signs of a systemic disease being observed in the animals, including significant weight loss and also intestinal invasion. The entire inflammatory process has been corroborated by studies of adhesion molecules such as E-Selectin, VCAM-1 and PECAM-1. A correlation between the time of appearance and the perseverance of the inflammatory process with E-Selectin and VCAM-1 expression was observed, but not with PECAM-1. The strain with a higher pathogenicity was able to invade deep vaginal tissues and thus, parasites could not be detected by vaginal washings. This may be an important cause of diagnosis and treatment failure. Also, by the different localization of trichomonads, it appeared that the battle between host and parasite took place in different areas dependent upon the characteristics of the strain.
Acta tropica 12/2009; 114(1):22-30. · 2.22 Impact Factor
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QSAR & Combinatorial Science. 01/2009; 28(1):9-26.
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Proceedings of the 12th International Electronic Conference on Synthetic Organic Chemistry. 01/2008;
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Bioorganic & medicinal chemistry letters. 01/2006; 16(7):1898-1904.
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ABSTRACT: Biological effects of piroxicam, metamizol, and S-adenosylmethionine (S-AMET) have been tested in NMRI mice infected intraperitoneally with Trichomonas vaginalis. An intraperitoneal treatment during ten preinfection days with piroxicam (10 mg/Kg/day), or metamizol (275 mg/Kg/day), but not with S-AMET (117 mg/Kg/day) induced a significant decrease of abdominal lesions and mortality, assessed by means of a pathogenicity index. The trichomonicidal activity of piroxicam, metamizol, and S-AMET was tested in vitro at the concentration of 300 microM, but found ineffective. These assays have shown the usefulness of the experimental trichomoniasis model for the study of the immunomodulating activity of synthetic drugs.
Parasite (Paris, France) 04/2005; 12(1):79-83. · 1.00 Impact Factor
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ABSTRACT: We have developed a new pharmacological screening assay for epimastigotes of Trypanosoma cruzi (clone CL-B5) that express the Escherichia coli LacZ gene. The assay is based on determining the activity of the cytoplasmic beta-galactosidase released into the culture on membrane lysis in the presence of the substrate chlorophenol red beta-D-galactopyranoside (CPRG). The experimental conditions were adjusted to find those in which the relationship between epimastigote number and CPRG absorbance was linear over the widest possible range. Absorbance was significantly correlated with the number epimastigote from 5x10(3) to 1.2x10(6) parasites/ml (r=0.98, P<0.01). The optimal final concentration of CPRG was 200 microM and the optimal incubation period was 6 h when parasites were incubated for 3 days. Once the assay was standardized, the trypanocidal activities of nifurtimox and benznidazole were determined both by CPRG assay and microscopic counting, demonstrating the methods utility for drug-screening. The efficacy obtained was comparable to that obtained with the manual method.
Parasitology Research 04/2005; 95(4):296-8. · 2.15 Impact Factor
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Bioorganic & medicinal chemistry. 01/2005; 13(22):6264-6275.
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ABSTRACT: Immunomodulator effect of Anapsos (Polypodium leukotomas extract) in NMRI (US Naval Medical Research Institute) outbred mice infected by the intraperitoneal route with 10(7) Trichomonas vaginalis has been tested. Gross histopathologic changes in abdominal organs and mortality rate, as a consequence of the pathogenicity of the protozoa and the immune response of the host, were evaluated. Among the different treatment regimes assayed, Anapsos at doses of 20 mg/Kg/day administered for 10 days before infection decreases the parasite pathogenicity index (PI) in the treated animals when compared to those of the untreated control group. The immunosuppressor treatments with azathioprine (100 mg/Kg/day x 1), cyclophosphamide (100 mg/Kg/day x 1), and FK-506 (10 mg/Kg/day x 10) significantly decreased the PI, while an immunostimulant treatment with glycophosphopeptical (13 mg/Kg/day x 10) increased it. These assays have shown the usefulness of the murine model of experimental trichomoniasis for the study of immunomodulator activity of natural or synthetic drugs.
Parasite (Paris, France) 01/2004; 10(4):303-8. · 1.00 Impact Factor
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ABSTRACT: Cholinesterase (ChE) and acid phosphatase (AP) activities, but not alkaline phosphatase activities, were detected in cytosolic and membrane-bound fractions of adult and infective-stage larvae of levamisole-resistant and levamisole-susceptible Haemonchus contortus. In contrast to other gastrointestinal nematodes, the ChE activity was higher in L3 than in adults and, in both cases, was mainly associated with membranes. ChE activity was inhibited by Triton X-100 and was only detected in membrane-bound fractions when the detergent was removed. Differences between resistant and susceptible L3 were observed in the response to inhibitors (cytosolic fraction) and in the enzymatic content (membrane-bound fraction). Phosphatase activity was detected at acidic pH in all fractions, being higher in the adult than in the L3 stage. In the former, most of the enzyme was localized in the membrane-bound fractions, whereas in the latter it was mainly in cytosolic fractions. This difference could be correlated with the activity in the gut. In inhibition assays, a difference between cytosolic fractions from resistant and susceptible adults was observed in their response to 1 mmol/L tartaric acid.
Veterinary Research Communications 01/2004; 27(8):611-23. · 0.82 Impact Factor
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ABSTRACT: Cholinesterase (ChE) and acid phosphatase (AP) activities, but not alkaline phosphatase activities, were detected in cytosolic and membrane-bound fractions of adult and infective-stage larvae of levamisole-resistant and levamisole-susceptible Haemonchus contortus. In contrast to other gastrointestinal nematodes, the ChE activity was higher in L3 than in adults and, in both cases, was mainly associated with membranes. ChE activity was inhibited by Triton X-100 and was only detected in membrane-bound fractions when the detergent was removed. Differences between resistant and susceptible L3 were observed in the response to inhibitors (cytosolic fraction) and in the enzymatic content (membrane-bound fraction). Phosphatase activity was detected at acidic pH in all fractions, being higher in the adult than in the L3 stage. In the former, most of the enzyme was localized in the membrane-bound fractions, whereas in the latter it was mainly in cytosolic fractions. This difference could be correlated with the activity in the gut. In inhibition assays, a difference between cytosolic fractions from resistant and susceptible adults was observed in their response to 1 mmol/L tartaric acid.
Veterinary Research Communications 11/2003; 27(8):611-623. · 0.82 Impact Factor
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ABSTRACT: A simple method to screen trichomonacides, based on the quantification of acid phosphatase (AP) activity, has been designed. Using p-nitrophenyl phosphate as chromogenic substrate, we first determined the optimal conditions for enzyme reaction. After seeding, a linear correlation between number of trichomonads and optical densities at 405 nm was obtained at 24 hr but not at 48 hr. Then, the inhibitory effect of metronidazole was assessed both by microscope counts and by AP determination. Similar values for 50% inhibitory concentrations (2.6 microM), with 95% confidence limits of 1.91-3.33 for microscopic and 2.21-3.05 for colorimetric method, were obtained. We concluded that the colorimetric method described in this investigation is suitable for pharmacological studies and for the screening of new, potential antitrichomonal agents.
Journal of Parasitology 11/2003; 89(5):1076-7. · 1.40 Impact Factor
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ABSTRACT: The immunomodulating effects of Anapsos, an aqueous hydrosoluble extract obtained from the rhizomes of the fern Polypodium leucotomos, on both pathogenicity and cytokine levels in serum (IFN-gamma/IL-4) were assayed in a Trichomonas vaginalis experimental model (BALB/c mice infected with 10(7) trichomonads and examined at day 15 after infection). Doses of 20 mg/kg/day administered for 10 days before the infection with the parasite induced a decrease of the experimental pathogenicity approximately 10-20% compared to controls. Gross histopathologic changes at abdominal organs and mortality rate, as a consequence of pathogenicity of the protozoa and the immune response of the host, were evaluated. IFN-gamma and IL-4 cytokines were determined on days -5, 0, 5, 10, and 15 postinfection by indirect ELISA. Treatment with PAL before infection modulates and downregulates the IFN-gamma concentration, while anticipates and upregulates the IL-4 level. The assays performed have showed the utility of the murine model of experimental trichomoniasis for the evaluation of immunomodulatory activity of synthetic or natural products.
Parasite (Paris, France) 04/2003; 10(1):73-8. · 1.00 Impact Factor
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ABSTRACT: We report the ultrastructural alterations induced on epimastigotes by nifurtimox and 5-nitro-2-thienyl-malononitrile (5NO2TM), a novel compound with anti-Trypanosoma cruzi activity. Parasites treated with concentrations of nifurtimox lower than usually employed for this kind of study showed vacuolisation, alterations of the mitochondria, the nucleus and the ribosomes. 5NO2TM caused the same kind of damage, but to a greater degree. This result correlates with the fact that cultures treated with this compound experienced a greater loss of viability.
Parasitology Research 03/2002; 88(2):97-101. · 2.15 Impact Factor
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ABSTRACT: The effect of nifurtimox and 5-nitro-2-thienylmalononitrile (5NO2TM), a novel compound with anti-Trypanosoma cruzi activity, upon vitality and HSP60 immunoreactivity of epimastigotes, has been determined. Both products showed no activity against epimastigotes at 0.1 microg/ml, while at 0.5 and 1 microg/ml, after 24 h of incubation, densities of these groups were significantly reduced, when compared to controls. An enhancement of HSP60 immunoreactivity was observed after 24 h in groups treated with 0.5 and 1 microg/ml nifurtimox. On the other hand, 5NO2TM had no effect.
Parasitology Research 09/2001; 87(8):615-8. · 2.15 Impact Factor
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ABSTRACT: Once known some biological characteristics of six Trypanosoma cruzi strains, randomly amplified polymorphic DNA (RAPD) analysis was made. Cluster analysis by UPGMA (unweighted pair group method analysis) was then applied both to biological parameters and RAPD profiles. Inspection of the UPGMA phenograms indicates identical clusters, so supporting that usefulness of biological parameters to characterization of T. cruzi strains still remains.
Memórias do Instituto Oswaldo Cruz 03/2001; 96(2):251-6. · 2.15 Impact Factor
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ABSTRACT: Biological parameters of five Trypanosoma cruzi strains from different sources were determined in order to know the laboratory behaviour of natural populations. The parameters evaluated were growth kinetics of epimastigotes, differentiation into metacyclic forms, infectivity in mammalian cells grown in vitro and parasite susceptibility to nifurtimox, benznidazole and gentian violet. Differences in transformation to metacyclic, in the percentage of infected cells as well as in the number of amastigotes per cell were observed among the strains. Regarding to pharmacological assays, Y strain was the most sensitive to the three assayed compounds. These data demonstrate the heterogeneity of natural populations of T. cruzi, the only responsible of infection in humans.
Memórias do Instituto Oswaldo Cruz 02/2001; 96(1):53-9. · 2.15 Impact Factor
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ABSTRACT: The cytotoxicity of 18 new 1,2,6-thiadiazin-3,5-dione 1,1-dioxides was evaluated. This group of products was previously assayed against epimastigotes of Trypanosoma cruzi and some of them showed a high antiprotozoal activity. Thereafter 13 compounds with a high anti-epimastigote activity and low cytotoxicity were selected to be assayed against amastigotes. Some of the products showed the same or even lower cytotoxicity than nifurtimox and benznidazole, but most of them were very toxic for macrophages at 100 microg/ml. Only one of the compounds had an anti-amastigote activity similar to that of reference drugs at 10 microg/ml, but unfortunately this disappeared at lower concentrations.
Folia parasitologica 02/2001; 48(2):105-8. · 1.81 Impact Factor
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ABSTRACT: The method most commonly used in screening of drugs for the treatment of Chagas' disease, microscopic counting of viable trypanosomes, is time-consuming, labor-intensive, and dependent on the observer. Although the tetrazolium dye [MTT; 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay is comparatively quick and accurate, it requires careful attention in design as well as in interpretation of the results. Therefore, we examined under various conditions the sensitivity and specificity of the MTT assay versus microscopic counting for determination of the viability of Trypanosoma cruzi for drug-screening purposes. We tested different concentrations of MTT in phenazine methosulfate (PMS) against T. cruzi epimastigotes of the Y strain in different stages of logarithmic growth. In our model, in tests of benznidazole and nifurtimox the optimal concentration of MTT was 2.5 mg/ml of PMS and the optimal incubation period was 75 min. This method detected parasite concentrations of approx. 500,000 epimastigotes/ml (P<0.01), and the linear correlation between absorbance values and numbers of epimastigotes per milliliter was very strong (approx. R = 0.99). The present MTT assay results in faster determination of the activity of compounds, is more objective, and enables testing of several drugs simultaneously.
Parasitology Research 12/2000; 86(12):999-1002. · 2.15 Impact Factor
