Content of total homocysteine and major aminothiols in rats with experimental renal ischemia.

The contents of total homocysteine, cysteine, and glutathione in blood plasma and tissue of rats with renal ischemia were measured by HPLC. Our study was performed on the "two-kidney, one-clip (0.13 mm)" model. The concentrations of homocysteine and cysteine in blood plasma from treated rats were higher than in sham-operated animals (control; by 36 and 14%, respectively). Homocysteine level in the intact and clipped kidneys of treated rats was 40% higher than in the control. However, no differences were found in homocysteine level in the ischemic and intact kidneys of treated animals. Cysteine concentration in the clipped kidney was lower than in the kidneys of intact and sham-operated animals (by 1.6 and 1.5 times, respectively). Glutathione concentration in the ischemic kidney did not differ from the control. No differences were revealed in the content of aminothiols in liver samples from rats of the treatment and control groups. Our results suggest that functional inactivation of one kidney is accompanied by impairment of homocysteine catabolism (trans-sulfonation).

[Elevated plasma homocysteine and glutathione level in patients with renal failure].

The levels of homocysteine (Hcy) and glutatione (Glt) were determined in plasma of 219 patients with different stages of chronic kidney disease (CKD) (94 patients received chronic bicarbonate hemodialysis and 125 patients were at predialysis stage). The elevated Hcy level was detected in an early stage of CKD and reached maximal values and spreading in the hemodialysis patients. The levels of total and reduced Hcy (tHcy and rHcy, respectively) were also higher in CKD patients: the proportion of rHcy in total pool of plasma Hcy was significally higher than in healthy subjects. In the group of non-dialysed patients the reverse dependance between glomerular filtration rate (GFR) value and Hcy plasma concentration was found. We did not find any correlation between Glt and GFR in predialysis patients, but there was direct dependance between Glt and tHcy plasma levels in this group. Glt plasma levels in dialysis patients were reliably lower than in predialysis ones. There was a lack of some correlation between Glt and tHcy in the haemodialysis group.

[Ionization of the acid-base groups of polyene antibiotics in aqueous solutions]. / Ionizatsiia kislotno-osnovnykh grupp polienovykh antibiotikov v vodnykh rastvorakh

The acid-base characteristics of polyenic antibiotics, such as nystatin, mycoheptin and levorin in aqueous solutions were studied. A special procedure provided the use of potentiometric titration for investigation of ionization of the groups of vater-insoluble substances. The ionization constants of the carboxylic and amine groups of the antibiotics at several temperatures were determined. It was found that ionization of the acid group did not practically depend on the temperature. At the same time the heat effect of the amine group ionization was significant and amounted to about 10 kcal/mole. Thermodynamic analysis of the ionization process of the polyenic antibiotics in aqueous solutions was performed. Integral components defining the process energetics were calculated.

[Acid-base properties and the thermodynamics of amphotericin B ionization in aqeous solutions]. / Kislotno-osnovnye svoistva i termodinamika ionizatsii amforteritsina B v vodnykh rastvorakh

Acid-base properties of amphotericin B, polyenic antibiotic in aqueous solutions was studied. A special procedure provided the use of potentiometric titration for investigation of ionization of the groups of the water-insoluble substance. The ionization constants of the carboxylic and amine groups of the antibiotic were determined at several temperatures. It was found that ionization of the acid group did not depend on the temperature. At the same time the heat effect of the amine group ionization was significant and amounted to about 10 kcal/mole. Thermodynamic analysis of the ionization process of amphotericin B in aqueous solutions was performed. Integral components defining the process energetics were calculated.