Decrease of virulence for BALB/c mice produced by continuous subculturing of Nocardia brasiliensis.

BACKGROUND: Subculturing has been extensively used to attenuate human pathogens. In this work we studied the effect of continuous subculturing of Nocardia brasiliensis HUJEG-1 on virulence in a murine model. METHODS: Nocardia brasiliensis HUJEG-1 was subcultured up to 130 times on brain heart infusion over four years. BALB/c mice were inoculated in the right foot pad with the bacteria subcultured 0, 40, 80, 100 and 130 times (T0, T40, T80 T100 and T130). The induction of resistance was tested by using T130 to inoculate a group of mice followed by challenge with T0 12 weeks later. Biopsies were taken from the newly infected foot-pad and immunostained with antibodies against CD4, CD8 and CD14 in order to analyze the in situ immunological changes. RESULTS: When using T40, T80 T100 and T130 as inoculums we observed lesions in 10, 5, 0 and 0 percent of the animals, respectively, at the end of 12 weeks. In contrast, their controls produced mycetoma in 80, 80, 70 and 60% of the inoculated animals. When studying the protection of T130, we observed a partial resistance to the infection. Immunostaining revealed an intense CD4+ lymphocytic and macrophage infiltrate in healing lesions. CONCLUSIONS: After 130 in vitro passages of N. brasiliensis HUJEG-1 a severe decrease in its virulence was observed. Immunization of BALB/c mice, with these attenuated cells, produced a state of partial resistance to infection with the non-subcultured isolate.

Hepatoprotective effect of Leucophyllum frutescens on Wistar albino rats intoxicated with carbon tetrachloride.

Many hepatoprotective herbal preparations have been recommended in alternative systems of medicine for the treatment of hepatic disorders. No systematic study has been done on protective efficacy of Leucophyllum frutescens to treat hepatic diseases. Protective action of L. frutescens methanol extract (obtained by maceration) was evaluated in an animal model of hepatotoxicity induced by carbon tetrachloride (CCl(4)). Wistar albino rats were divided into five groups. Group I was normal control group; Groups II-V received CCl(4). After inducing hepatic damage, Group II served as control CCl(4); Group III was given silymarin as reference hepatoprotective; and Groups IV and V received different doses of plant extract. Liver marker enzymes were assayed in serum. Samples of livers were observed under microscope for the histopathological changes. Levels of marker enzymes such as alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were increased significantly in CCl(4) treated rats (Group II). Groups IV and V intoxicated with CCl(4) and treated with L. frutescens methanol extract significant decreased the activities of these two enzymes. Also these groups resulted in less pronounced destruction of the liver architecture, there is not fibrosis and have moderate inflammation compared with Group II. The present study scientifically validated the traditional use of L. frutescens for liver disorders. In conclusion the methanol extract of L. frutescens aerial parts could be an important source of hepatoprotective compounds.

Effect of clofibric acid on desmin and vimentin contents in rat myocardiocytes.

The aim of this experimental study was to analyze in vitro effects of clofibric acid on vimentin and desmin contents in rat myocardiocytes, which was carried out in primary myocardiocyte cells that were treated only with clofibric acid at 0.1 mM. The measurement of vimentin and desmin were done by Western blotting and densitometry. This study showed that myocardiocytes exposed to clofibric acid exhibit a 26.3% decrease in vimentin and a 42.1% decrease in desmin. Considering the role that these intermediate filaments play in the anchorage and cellular organization of myocardiocytes, the decrease of desmin and vimentin observed in cells treated with clofibric acid may be partially responsible for the adverse effects observed in patients. In conclusion, the alteration of cytoskeletal proteins may be a cause of cardiopathy in patients treated with these compounds.

Trichomonas vaginalis: identification of a phospholipase A-dependent hemolytic activity in a vesicular subcellular fraction.

Trichomonad total extracts (TTE), or vesicular (P30) and soluble (530) subcellular fractions from 3 pathogenic Trichomonas vaginalis strains (GT-3. GT-13. and GT-15), lysed both human and Sprague-Dawley rat erythrocytes in a time- and dose-dependent manner. The entire hemolytic activity of TTE was located in P30, showing 2 peaks of maximum activity, one at pH 6.0 and another at pH 8.0. in the presence of 1 mM Ca2+. Hemolytic activity on rat erythrocytes was greater at pH 6.0 16.71 +/- 0.33 hemolytic units IHU]/mg/hr to 11.60 +/- 0.24 HU/mg/hr) than at pH 8.0 (3.81 +/- 0.30 HU/mg/hr to 5.75 +/- 0.65 HU/mg/hr). and it was greater than that on human red blood cells at pH 6.0 (2.67 +/- 0.19 HU/mg/hr to 4.08 +/- 0.15 HU/mg/hr) or pH 8.0 (2.24 +/- 0.0 9 HU/mg/hr to 2.81 +/- 0.06 HU/mg/hr). The alkaline and acidic hemolytic activity diminished (60-93% at pH 6.0 and 78-93% at pH 8.0) by the effect of 80 microM Rosenthal's inhibitor, which also inhibited 27-45% and 29-54% trichomonad alkaline and acidic phospholipase A activities, respectively. Vesicles, vacuoles, and hydrogenosomes were rich in P30. Trichomonas vaginalis has a hemolytic PLA, which could be involved in its cytopathogenic mechanism.