Inhibition of Trypanosoma cruzi by plant extracts used in Chinese medicine.

In this work, we assessed the effect of extracts obtained from 17 plants used in traditional Chinese medicine. These extracts were tested in vitro with the epimastigote form of Trypanosoma cruzi, clone Bra C(15) C(2), at 27 degrees C in F-29 medium at a concentration of 100 microg/ml in axenic cultures. Allopurinol was used as reference drug. Seven plant extracts showed inhibitory activities lower than 25%. Pueraria lobata, Mahonia beaei, Dictamus dasycarpus, Kochia scoparia, Sophora flavescens and Ligustrum lucidum showed effects with inhibition values between 25% and 60%, whereas Lithospermum erythrorhizon, Saussurea lappa, Melia toosendan and Cinnamomum cassia showed the greatest inhibitory activity of 100%. The IC(50) of these extracts were: 0.4, 2.4, 1.8 and 3.9 microg/ml, respectively. The MTT assay was made and did not show cytotoxic activity. These results allowed us to suggest that L. erythrorhizon, S. lappa, M. toosendan and C. cassia could be a source of new compounds against T. cruzi.

Inhibition of Trypanosoma cruzi growth by medical plant extracts.

This study describes the screening of extracts obtained from 18 plants and two fungi used in the Chinese and Mediterranean traditional medicines on epimastigote forms of Trypanosoma cruzi. The extracts were tested against epimastigote of T. cruzi Bra C15C2 clone in vitro at 27 degrees C and at a concentration of 250 microg/ml in axenic culture. Angelica dahurica, A. pubescens, A. sinensis, Astragalus membranaceus, Coptis chinensis, Haplophyllum hispanicum, Phellodendron amurense, Poria cocos, Ranunculus sceleratus and Scutellaria baicalensis showed significant effects against the parasite with a percentage of growth inhibition between 20 and 100%. C. chinensis and R. sceleratus showed the greatest activity with IC(50) values of 1.7 microg/ml for C. chinensis and 10.7 microg/ml for R. sceleratus. These activities are greater than that of allopurinol. C. chinesis and R. sceleratus extracts did not show cytotoxic effects on rat polimorphonuclear cells using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide and lactic dehydrogenase assays. These results allowed us to suggest that R. sceleratus and C. chinensis could be a source of new compounds clinically active against T. cruzi.

Effect of physical activity on the pharmacokinetics of ceftazidime in mice.

BACKGROUND: The aim of the present work was to assess comparatively the pharmacokinetic profile of ceftazidime (CAZ) in trained and non-trained mice. METHODS: The study was performed on 256 mice divided at random into four groups: long-term physically trained mice with (E1a) and without (E1b) physical activity prior to the administration of CAZ, and untrained mice with (E2a) and without (E2b) physical activity prior to the administration of the antibiotic. CAZ was administered intramuscularly (25 mg/kg) to all mice, and blood samples were obtained at different time points. The plasma concentrations of CAZ were determined by HPLC and analyzed by non-compartmental models. RESULTS: The area under the curves in groups E1a and E2a (27.3 and 22.9 microg x ml(-1) x h, respectively) were different compared to the other groups [(E1b) = 11.1 and (E2b) = 15.6 microg x ml(-1) x h; p < 0.05]. Differences were observed between the concentration-time of CAZ in E1a compared to E1b, E1a versus E2a, E1a versus E2b, E1b versus E2a and E1b versus E2b (p < 0.05). CONCLUSION: Physical activity performed prior to CAZ administration modified the pharmacokinetic profile of the drug administered to mice.

The restoring effect of trifluralin and benznidazole on the abnormal fatty-acid pattern induced by Trypanosoma cruzi in the liver microsomes of infected mice.

The fatty-acid composition of liver lipids from mice infected with Trypanosoma cruzi (clone H510C8C3) or uninfected mice was investigated. The infected animals were treated orally for 30 days, with trifluralin (TFL) or benznidazole (BNZ), each at 100mg/kg.day, or only with the peanut oil used as the drug vehicle. The uninfected mice were also given the peanut oil. The treatments were stopped 10 days before the animals were killed. The liver microsomal lipids of each mouse were isolated and then analysed by gas-liquid chromatography. In terms of the total lipids, untreated infection evoked a significant increase in saturated fatty acids and the members of the n-9 fatty-acid family, with a concomitant decrease in the polyenoates of the n-3 and n-6 fatty-acid series. Each lipid subclass was affected to a different extent, the phospholipids being affected most. All lipid fractions, apart from the cholesterol esters, showed a significant increase in the proportion of n-9 isomers. Infection also produced a marked increase in the absolute amounts of triacylglycerides, cholesterol and cholesterol esters in liver microsomal membranes. After BNZ or TFL treatment, the fatty-acid pattern of mice that had been infected was indistinguishable from that of the control mice. The possible role of desaturase activity in the alterations observed is discussed.

[Trypanosoma cruzi: obtaining extracellular amastigotes and studying their development under different culture conditions]. / Trypanosoma cruzi: obtención de amastigotes extracelulares y estudio de su crecimiento en diferentes condiciones de cultivo.

This work describes a protocol to obtain pure populations of extracellular amastigotes of Trypanosoma cruzi. The amastigote stage was obtained by means of temperature changes and human plasma added to the culture medium. Epimastigotes (clon BraC15C2) were first grown in F69 medium at 27 degrees C during 96 h and then at 36.5 degrees C. After three subcultures of 96 h each at the latter temperature a subsequent incubation in the presence of 5% human plasma, was needed to obtain a population of amastigotes that could be maintained indefinitely in the F69 or F29 media. This amastigote population was similar morphologically to that obtained through other methods. The kinetic of growth depended on the culture medium used (F29 or Brain-Heart Infusion, BHI). When culture was incubated at 27 degrees C in both media, the pre-exponential and logarithmic phases of growth were observed at 72-96 h and 24-48 h respectively. The change in stage from amastigote to epimastigote dependent whether amastigote were subcultured or not. The growth of amastigotes in BHI medium at 36.5 degrees C did not occurred. The growth of amastigotes was similar to those observed at 27 degrees C when F29 medium was used although the transformation to epimastigotes did not take place at this temperature. A population over 99% of amastigotes were maintained at 36.5 degrees C indefinitely by means of subcultures in F29 medium.

Graft versus host disease in autologous stem cell transplantation.

Relapse remains the major cause of mortality in haematological malignancies treated with autologous stem cell transplantation (ASCT). Graft versus tumour reaction (GVT) associated to autologous graft versus host disease (GVDH) may contribute to eliminate minimal residual disease (MRD) after ASCT. Eighty patients with several diagnostics were submitted to ASCT. After stem cell infusion, patients randomised in 4 groups. Groups were treated as follows: Group A received either a IFN (alpha Interferon--1,000,000 U/d), Cyclosporine A (CSA--1 mg/-kg/d intravencus) for 28 days, and granulocyte-macrophage colony stimulating factor (GM-CSF-250/m2/d) until engraftment; B: CSA (same dose and way) and GM-CSF; C: CSA (1 mg/kg/d orally) and GM-CSF and D: only GM-CSF. Patients were inspected daily and if skin rash was detected, a skin biopsy was obtained at that moment, otherwise biopsies were obtained at day 21 after ASCT. GVHD was positive in 23 patients (13 from group A and 10 from group B). All cases were grades I and II. A majority of CD4+ T lymphocytes was seen in skin infiltrates. No significant differences were seen in WBC and platelets engraftment times, antibiotic administration or hospitalisation days required among the four groups. With a median follow up of 18 months, there were no differences in disease free survival (DFS) or overall survival (OS) between the patients who developed GVHD and the others. However, considering that myeloma cells do not express antigen MCH II, which is necessary for GVT effect, we excluded patients with multiple myeloma (MM) from survival analysis, thus obtaining a significant difference in OS results between patients who developed GVHD and those in whom this reaction was not observed (81% vs 58% p:0.05). We conclude that pharmacological induction of GVHD in ASCT is possible with CSA administration (1 mg/kg/d i.v.). Development of GVHD showed a better outcome for patients in our study except for those patients with MM. This results must be confirmed by a longer follow up of our patients and further studies.

Effect of the chloroform extract of Tanacetum vulgare and one of its active principles, parthenolide, on experimental gastric ulcer in rats.

This study examines the anti-ulcerogenic activity of a chloroform extract of Tanacetum vulgare and purified parthenolide, the major sesquiterpene lactone found in the extract. Gastric ulcers induced by oral administration of absolute ethanol to rats were reduced dose-dependently by oral pretreatment of animals with the chloroform extract (2.5-80 mg kg(-1)) or parthenolide (5-40 mg kg(-1)). When administered 30 min before challenge with the alcohol the protection ranged between 34 and 100% for the extract and 27 and 100% for parthenolide. When the products were administered orally 24 h before treatment with ethanol, 40 mg kg(-1) of the extract and of the lactone reduced the mean ulcer index from 4.8+/-0.3 for control animals to 1.4+/-0.2 and 0.5+/-0.1, respectively. The products also prevented alcohol-induced reduction of the number of sulphydryl groups within the gastric mucosa (50.6+/-2.3 microg (mgprotein)(-1) for normal animals compared with 17.7+/-3.0 microg (mg protein)(-1) for alcohol-treated animals). Administration of the extract (80 mg kg(-1)) or parthenolide (40 mg kg(-1)) 24 h before ethanol treatment restored the numbers of mucosal -SH groups to values near those found for normal animals. These results suggest that the products assayed, in particular parthenolide, might find therapeutic application, although further work is required to establish their profit/risk ratio.

Effect of arsenic (V) on the antioxidant defense system: in vitro oxidation of rat plasma lipoprotein.

Adult male rats were treated orally with sodium arsenate (10 mg As/kd/day) for 2 days, and in increase in hepatic glutathione level was seen. Ascorbic acid content increased in both liver and plasma of intoxicated animals. Hepatic activities of superoxide dismutase and glutathione peroxidase did not change with the treatment and there was no increase in the level of lipid peroxidation measured as thiobarbituric acid-reacting substances (TBARS). Arsenic decreased the plasma level of uric acid and increased the plasma triglycerides content without modifying vitamin E levels. Both total lipoproteins and very low density lipoprotein plus low density lipoprotein (VLDL + LDL) fractions demonstrated greater propensity for in vitro oxidation than the corresponding untreated rats. The last finding might be a useful parameter for determining the degree of oxidative stress in the initial steps of intoxication with arsenic.

The pharmacokinetics of ceftazidime in lactating and non-lactating cows.

The pharmacokinetics of ceftazidime (CAZ) were studied in lactating (LTG) and non-lactating (NLTG) cows. Two groups (LTG and NLTG) of 5 healthy dairy cows were given ceftazidime (10 mg/ kg body weight) intravenously (i.v.) and intramuscularly (i.m.). Serum and milk (LTG) and serum samples (NLTG) were collected over a 24-h period post-administration. CAZ concentrations in serum and milk were determined by high-performance liquid chromatography, and an interactive and weighted-non-linear least-squares regression analysis was used to perform the pharmacokinetic analysis. The pharmacokinetic profiles in LTG and NLTG cows which had received CAZ i.v. fitted a three-compartment model and a two-compartment model, respectively. The CAZ concentration-time curves in serum and the area under the curve were greater and more sustained (p < 0.05) in the LTG cows by both routes, while the serum clearance (Cls = 72.5 +/- 18.1 ml/h per kg) was lower (p < 0.05) than that in the NLTG cows (Cls = 185.9 +/- 44.2 ml/h per kg). CAZ given i.v. exhibited a relatively long half-life of elimination (t1/2 beta (LTG) = 1.1 +/- 0.2 h; t1/2 beta (NLTG) = 1.4 +/- 0.3 h). Compared with other cephalosporins, CAZ had good penetration into the mammary gland (47.7 +/- 38.2% for CAZ i.v.; 51.1 +/- 39.0% for CAZ i.m.). Finally, the bioavailability of CAZ (F(LTG) = 98.9 +/- 36.8%; F(NLTG) = 77.1 +/- 25.3%) was suitable for its used by the i.m. route in lactating and non-lactating cows.

[Trypanosoma cruzi: influence of human plasma on the morphogenesis of blood trypomastigotes in a cell-free culture media]. / Trypanosoma cruzi: influencia del plasma humano en la morfogénesis de tripomastigotes sanguíneos en un medio de cultivo acelular.

Morphogenesis of blood stream trypomastigotes in the cell free culture medium F69 at 37 degrees C for 10 days showed qualitative differences either with or without human plasma. Without human plasma, blood stream trypomastigotes performed only one cycle before disappearing and the culture kept growing as amastigotes and epimastigotes until the end of the experiment. In contrast, human plasma induced multiple cycles of transformation. The sequence was blood stream trypomastigotes, regressive parasites, amastigotes, progressive parasite and again trypomastigotes. Human plasma preserved the trypomastigote stage, produced a blockade of the epimastigote stage and inhibited the division of amastigotes. In this experimental model, human plasma modified the biological cycle of T. cruzi by inducing or inhibiting different stages.

Pharmacokinetics and penetration into tissue fluid of cefotaxime in bovines.

Concentrations of cefotaxime in serum and tissue fluid were studied in the bovine after intravenous and intramuscular administration at a dosage of 10 mg.kg-1 body weight. Steers implanted subcutaneously with tissue cages were used. After intravenous bolus administration, profiles of mean concentrations in serum over time were described by a two-compartment open model. The rate constant of elimination was 1.4 +/- 0.3 h-1 and the half-life 0.6 +/- 0.1 h. The rate constant of distribution was 11.5 +/- 1.9 h-1, and the half-life was 0.06 +/- 0.01 h. The volume of distribution at steady state was 250.6 +/- 37.3 ml.kg-1. The area under the curve was 31.8 +/- 7.4 micrograms.ml-1.h. The penetration ratio into tissue fluid was 36.5 +/- 15.4%. After intramuscular injection, the half-life was 1.1 +/- 0.3 h, the area under the curve was 27.5 +/- 6.8 micrograms.ml-1.h, and the penetration ratio into tissue fluid was 47.1 +/- 15.8%. The concentrations in tissue fluid after intravenous and intramuscular administration of cefotaxime were elevated during a 6-hour period after administration.

Effects of glucose on glycogen synthetase, phosphorylase, and glycogen deposition in the perfused rat liver.

An increase in the perfusate glucose concentration from near zero to about 11 mM increased glycogen synthesis in the perfused, isolated rat liver from zero to a value about half the maximum seen in the intact animal. Increased synthesis appeard to due not only to provision of substrate but also to conversion of glycogen synthetase to the active form and of glycogen phosphorylase to the inactive form. These glucose effects, which are apparently independent of changes in levels of hormones or adenosine 3':5'-cyclic phosphate, may be physiologically significant for control of the blood glucose level.