[Sodium azide as indirect nitric oxide donor: researches on the rat aorta isolated segments].

A comparative investigations of heme-containing enzymes inhibitors NaN3 and NaCN effects on the rat aorta isolated segments tone has shown that NaN3 in the range of very low concentrations from 10(-9) to 10(-6) M displays pharmacological activity characteristic of nitric oxide (NO) donors, which is inhibited by NaCN. The value of vasodilatation, caused by NaN3, was also decreased in the presence of soluble guanylate cyclase inhibitor ODQ (10(-5) M). It was found that H2O2 injection to physiological solution containing NaN3 and horseradish peroxidase or catalase lead to NO2- accumulation in it, which was blocked by NaCN. The nonenzymic NaN3 oxidization by hydrogen peroxide was not found in control experiments. NaN3 physiological activity dependent on NO-donating properties of this traditional inhibitor of heme-containing enzymes is discussed.

Adsorption of direct-acting and indirect-acting mutagens by various dietary fibers.

The protective effect of dietary fiber on human cancer has received great attention during the last decades. Because dietary fiber constitutes a large group of complex polysaccharides with various solubilities, degrees of lignification, chemical compositions and structural arrangements, several mechanisms for their effects have been proposed. In this study, in vitro binding capacities of various dietary fibers (potato fiber and glucomannan) and dietary fiber constituents (pectic acid and cellulose) against indirect mutagen 2-amino-3-methyl-3H-imidazo (4,5-f) quinoline (IQ) and direct-acting mutagen sodium azide were investigated. Direct-acting mutagen sodium azide was not adsorbed to the dietary fiber and dietary fiber constituents of 0 degree C, pH 4.5 and 37 degrees C, pH 7.0. However, indirect-acting mutagen 2-amino-3-methyl-3H-imidazo (4,5-f) quinoline (IQ) were sorbed by them in variable ratios at 0 degree C, pH 4.5 and 37 degrees C, pH 7.0. The differences between the in vitro binding capacities of the samples at two experimental conditions were found to be statiscially significant (P < 0.01). IQ was not released from the dietary fibers and constituents in distilled water.

Uptake of N,N-dimethyl-2-phenylethylene HCl into acini cells removed from rabbit lacrimal glands.

Acini cells were obtained from the lacrimal gland of the white New Zealand rabbit. Following isolation and purification, the cells were used to study the uptake of N,N'-dimethyl-2-phenylethylamine HCl (AF2975), which was found to be sodium- and proton-independent, but energy-dependent. Uptake was mainly accomplished via a carrier-mediated transport system for which a Km of 8.72+/-0.96 mM, a Vmax of 602.6+/-41.3 nmol/mg of protein/min, and an exponential coefficient of 2.55+/-0.46 were obtained following a least squares nonlinear fit to the Hill equation. With the addition of the metabolic inhibitors, sodium azide or 2,4-dinitrophenol, the initial uptake rates were reduced from the control experiments by 35.7% and 26.2%, respectively.

Meio de cultura para isolamento de Streptococcus mutans / Culture medium for selection of Streptococcus mutans

Um meio seletivo para Streptococcus mutans foi pesquisado com amostras de coleçäo e com saliva. Verificou-se que o meio, para o isolamento dessa bactéria da saliva, deve conter substâncias inibidoras para bactérias gram-negativas. A azida Sódica mostrou-se mais inibitória para o S. mutans do que o Acetato de Tálio, que, na concentraçäo de 0,1 por cento apresentou melhor resultado para o isolamento dessa espécie na saliva