Fiziologicheskiĭ zhurnal最新文献

Force-frequency relations in the isolated papillary muscles of rats and guinea-pigs were compared using isometric force measurement technique. Stimulation frequency varied between 0.33 and 4 Hz. Under normal conditions the rat papillary muscle exhibits a negative force-frequency dependence which differs from ventricular preparations in many other mammals. Caffeine (10 mmol/l) introduced into the bath solution abolishes a negative force-frequency dependence in the papillary muscle of rat. During incubation of the rat ventricular preparations in the caffeine-containing solution the force-frequency relations measured on these muscles display the same behaviour as in guinea pig preparations. Caffeine has induced no changes in the force-frequency relations of guinea-pig ventricular preparations. A conclusion is made that caffeine-sensitive intracellular calcium stores participate in species-determined differences in force-frequency relations of the ventricular muscles.

The mechanisms of lipid peroxidation (LP) intensification in the rat myocardium, brain and liver were studied under hypoxic hypoxia and hemic hypoxia. The level of intensification depends on the type of hypoxia and is characterized by tissue specificity. It is shown that LP is activated by hypoxia. This activation is more pronounced under hemic hypoxia associated with more marked catecholamine accumulation, deficiency of the antioxidant glutathione system, decrease of the cytochrome c-oxidase activity. The level of lipid peroxides was higher in the rat liver under both types of hypoxia.

The human colostrum stimulated by suboptimal doses (50 ng/ml) of lipopolysaccharide (LPS) has induced proliferation of mouse splenocytes. Addition of the human colostrum has elicited a rise in splenocyte culture supernatants. Effect of human colostrum on Ig synthesis was dose-dependent and was expressed at 0.5% concentrations in the medium. In contrast to the human colostrum, the bovine colostrum exerted a suppressive effect on proliferation of mouse splenocytes and Ig synthesis induced by suboptimal doses of LPS. Bovine casein did not significantly affect the Ig synthesis by mouse splenocytes. Suppression of the Ig synthesis was associated with bovine colostral globulins. Using the ELISPOT method we have found that a rise in the Ig level in the culture after treatment with the human colostrum was due to an increase of the number of IgG2a-secreting cells. B-cell promoting fraction was found after HPLC gel-filtration. The molecular weight of this fraction was 70-75 kD.

The antibody immune response and development of immunological memory to Murobacterium bovis antigens were studied in experiments carried out on CBA and BALB/c mice. Optimal antigen does for primary immune responses were 1 mg of both live and killed bacterial cells. In contrast to the primary antibody production, formation of the immunological memory was found to depend greatly on the viability of M. bovis injected. The levels of circulating immune complexes increased during secondary antibody responses demonstrated only in mice primed with live mycobacteria but not with killed ones. Aggregation of a purified derivative of tuberculin protein by crosslinking polypeptides using chromium chloride resulted in a significant enhancement of their immunogenic properties providing the high level of immunological memory formation as well as production of the antibodies against M. bovis specific antigens.

An artificial increase of a pool of bile acids due to administration of dehydrocholic, chenodesoxycholic acid preparations and dry bile in 22 healthy people and 179 patients with chronic cholecystitis has been studied for its effect on regulation of the gallbladder filling on an empty stomach using daily echocholecystometry. Filling of the gallbladder under artificial sequestration of bile acids during duodenal probing, enterosorption and cholatogenic diarrhea was studied in 55 patients with cholecystitis. It has been proved that an increase of the pool of bile acids induces intensification of the gallbladder filling on an empty stomach, while a decrease of the pool, vice versa, causes attenuation of its filling. It is found out a size of a pool of bile acids in the human organism is an important humoral factor in the physiological mechanism of the gallbladder filling regulation.

Introduction of liposomas has been studied in experiments on Wistar rats for its effect on oxygen demand by tissues of the brain great hemispheres, lungs, liver and femoral muscle under acute hypoxic hypoxia due to inhalation by an animal of gas mixtures containing of 6.7-7.1% of O2. It is shown that after introduction of phospholipid liposomes as a lipin preparation against a background of acute and grave forms of hypoxic hypoxia the oxygen demand of tissues remains practically at the level of control values. This proves absence of the tissue oxygen debt that usually develops at hypoxic states. It is concluded that the organism tissues in the presence of liposomas do not practically suffer from the oxygen deficiency and introduction of lipin may be effective to prevent from development of the secondary tissue hypoxia.

It has been shown that in experiments where a negative feed-back method has been used, triiodothyronine and beta-adrenomimetic isopropylnoradrenaline exert a significant influence on the work of the whole system of thermoregulation in white rats. This is observed in an upward displacement of the "set-point" temperature.

The chronic hepatitis in Wistar rats was induced by seven subcutaneous injections of carbon tetrachloride (0.3 ml of 50% oil solution per 1 kg of body mass) made each third day. It was shown that cytochromes P-450 and b5 content, demethylase activity in the liver microsomal fraction as well as the oxygen tension in the liver tissue were decreased, while lipid peroxidation was intensified. The PHA-induced blood lymphocyte blastogenesis was inhibited and concentration of circulating immune complexes in the blood was higher than that in intact animals.

The experiments on dogs with acute myocardial infarction have revealed that fenigidine, a new pharmaceutical form of calcium antagonist, does not provoke a deterioration of the left ventricular function, but normalizes it. The coronary blood flow greatly increases under the influence of remedy (more than 3 hours).

The energy metabolism and indices of the adenylate-cyclase system in kidneys of rats with acute fluoric intoxication have been studied. It has been determined that the use of hyperbaric oxygenation prevents deep disturbances of energy metabolism in the renal tissue and restricts the increase of adenosine monophosphate concentration. Moreover the survival rate of animals has increased by 30% for the first 24 hours.