Inhibition of cytosolic rat hepatic glutathione S-transferase activities by bromosulfophthaleins

Summary The enzymatically catalyzed conjugation of glutathione with 1-chloro-2,4-dinitrobenzene and styrene-7,8-oxide is inhibited by tetrabromosulfophthalein in a non-competetive way, although tetrabromosulfophthalein itself is a substrate for glutathione S-transferases. Dibromosulfophthalein, which is not a substrate for glutathione S-transferases, inhibits the 1-chloro-2,4-dinitrobenzene conjugation competetively and the styrene-7,8-oxide conjugation non-competetively.     

Interaction of benznidazole reactive metabolites with nuclear and kinetoplastic DNA, proteins and lipids from Trypanosoma cruzi

Epimastigotes of Trypanosoma cruzi (Tulahuen strain Tul 0 stock) biotransform benznidazole (N-benzyl-2-nitro-1-imidazole acetamide) to reactive metabolites that bind covalently to DNA, proteins and lipids of the parasite. These effects might be related to the trypanocidal action of benznidazole, a chemotherapeutic agent against Chagas' disease.     

Criteria for the evaluation of the antirheumatic (antiinflammatory drugs in man]

Comparison of 5 antiinflammatory drugs and placebo in a double blind, short term, cross-over trial conducted in patients suffering from rheumatoid arthritis. 15 measurements were used and studied. With classical unidimensional statistical tests it was not possible to discriminate active drugs between them. Multidimensional analysis (correspondance analysis and discriminant analysis) are more sensitive and allow us to distinguish active drugs with only 11 criterion.     

An insect acetylcholinesterase inhibitor from compound eyes ofTriatoma infestans (Hemiptera)

Summary The presence of an acetylcholinesterase inhibitor in the compound eyes of adultTriatoma infestans was demonstrated. The inhibitory activity was localized in the ocular pigments separated by disc gel electrophoresis. The inhibitor was selective against insect acetylcholinesterase, reversible, noncompetitive and heat stable.This work was supported by a research grant from the Comisión de Investigaciones Cientificas de la provincia de Buenos Aires, Argentina.     

Electrophoretic variation in esterases in 3 wild-type and respective mutant strains ofAspergillus flavus

Summary Wild-type strains and auxotrophic mutants ofAspergillus flavus, differing regarding aflatoxin production, were tested for esterases isozymes. Esterases variation was found in all strains used, and a possible correlation between the pattern of esterase bands and aflatoxin production is suggested.Acknowledgment. The authors are thankful to the National Council for the development of Science and Technology (CNPq) and Assistance to Research for São Paulo State (FAPESP) for financial assistance.     

Comparison of exogenous cell fusion induced by a wild and two mutant strains of sheep Visna virus]

Exogen cell fusion induced in vitro by a wild strain of Visna virus of Sheep is compared with two mutant strains isolated from the precedent. One of them produces large plaques in vitro (strain LPF), and the other produces small plaques (strain SPF). These strains behave in different ways according to infection multiplicity, type of cells, temperature and timing of fusing activity. Taking the wild strain K 796 as a base of reference, the strain SPF seems to have a higher rate fusing activity and the strain LPF lower rate of fusing activity.