Identification of the products of oxidation of quercetin by air oxygen at ambient temperature.

Oxidation of quercetin by air oxygen takes place in water and aqueous ethanol solutions under mild conditions, namely in moderately-basic media (pH approximately 8-10) at ambient temperature and in the absence of any radical initiators, without enzymatic catalysis or irradiation of the reaction media by light. The principal reaction products are typical of other oxidative degradation processes of quercetin, namely 3,4-dihydroxy-benzoic (proto-catechuic) and 2,4,6-trihydroxybenzoic (phloroglucinic) acids, as well as the decarboxylation product of the latter--1,3,5-trihydroxybenzene (phloroglucinol). In accordance with the literature data, this process involves the cleavage of the gamma-pyrone fragment (ring C) of the quercetin molecule by oxygen, with primary formation of 4,6-dihydroxy-2-(3,4-dihydroxybenzoyloxy)benzoic acid (depside).

[The effect of acetate and bicarbonate on the tolerance for hemodialysis therapy in chronic kidney failure].

Effects of acetate and bicarbonate dialysates on tolerance to dialysis have been examined in 30 patients with chronic renal failure (CRF). Symptomatic homeostatic impairment (nausea, vomiting, headache) and cardiovascular instability (tachycardia, arrhythmia, dyspnea) were less common (p less than 0.05) in bicarbonate dialysis.

[Vapor-phase gas chromatographic determination of acetate in the blood].

The suggested gas chromatographic vapor phase analysis of the blood for the direct determination of the blood acetate concentration is performed with Soviet equipment and is based on expulsion of acetic acid from its salts and other derivatives after addition of potassium bisulfate and heating of the blood sample at +105 degrees C for an hour in a hermetically sealed flask. To directly measure acetate, a certain vapor phase volume is let into the gas chromatographic evaporator after equal distribution of acetate in the gas and liquid phases is achieved. This method was used to measure the blood acetate levels in the patients with renal insufficiency treated by hemodialysis.

[Head-space gas chromatographic analysis in the rapid diagnosis of anaerobic infections].

The comparison of the results obtained by the gas-chromatographic vapor-phase analysis and by the bacteriological analysis of exudate samples, taken from patients with intraperitoneal and intrapleural infections, has demonstrated high reliability of the chromatographic method. Despite the presence of some discrepancies between the results of the vapor-phase analysis and the bacteriological analysis due to the difficulties of the microbiological isolation of anaerobes and the specific features of their metabolism, the diagnostic value of the gas-chromatographic method has been confirmed.