The autologous intestinal microflora in the postresuscitation period after acute blood loss in rats

In this work the data obtained in the study of intestinal microbiocenosis in rats on the third day of the postresuscitation period after acute blood loss are presented. The quantitative and qualitative shifts of microflora at different biotopes, such as the wall of the small intestine, the parietal microflora of Peyer's patches, the contents and wall of the large intestine, have been characterized. Some specific features of dysbiotic changes have been revealed in comparison with the shifts of intestinal microflora in cases of dysbacteriosis caused by other reasons. The translocation of different microorganisms, including Bacterium bifidum and lactobacilli, into mesenteric lymph nodes, the liver, the spleen and the blood has been observed.     

Modulation of the membrane potential of intact guinea pig aortic endothelium

The role of different ion conductances in regulation of the membrane potential (MP) of resting and agonist-stimulated intact endothelium from the guinea pig aorta was investigated. Under resting conditions, the MP measured by the patch-clamp technique varied within the range from –29 to –56 mV (the mean value of –40.8 ± 8.1 mV). Blockers of anomalous (inward) rectifier potassium channels cesium (100 µM) and barium (100 µM) exerted no effect on the MP of endothelium. Superfusion of preparations with calcium-free solution and application of 2 mM nickel depolarized the endothelium. ATP (10 µM) induced hyperpolarization of endothelium with the mean amplitude of 11.4 ± 0.6 mV. The initial phase of this hyperpolarization depended on the external potassium concentration and on the state of intracellular calcium stores, whereas the prolonged phase required the presence of external calcium. In the absence of external calcium, in 25% of recordings transient hyperpolarization was followed by depolarization, which was not observed after substitution of external NaCl for choline. It was concluded that basal activity of calcium-dependent potassium channels contributes to the regulation of the MP of resting endothelium. Stimulation with ATP led to activation of calcium-dependent potassium and nonselective cationic channels. Activation of the former channels produced the initial phase of hyperpolarization, whereas activation of the second channel type evoked the prolonged phase of hyperpolarization.Neirofiziologiya/Neurophysiology, Vol. 28, No. 6, pp. 260–266, November–December, 1996.     

Changes in the functional state of the adrenal glands in experimental bronchospasm in dogs

Changes in the adrenal functional state were revealed during the development of bronchoconstriction induced by allergen inhalation in 7 dogs sensitized with ovalbumin. The decrease in V1 (expiratory flow-volume) on an average by 58% was noted after inhalation of 1000 microG of ovalbumin. The significant decrease in II-hydroxycorticosteroids (II-OCS), adrenaline, noradrenaline, dopamine, and a tendency to the increase in histamine content were observed in the venous blood plasma. The decrease in the adrenaline content in plasma apparently contribute to the development of early bronchoconstrictor response, and the decrease in II-OCS maintain the development and the progress of late bronchoconstrictor response.     

Differential cell mutability during oogenesis and exposure to ethyleneimine and ethylmethane sulfonate in different Drosophila melanogaster lines

The rate of recessive sex-linked lethal mutations (RLM) was estimated by brood pattern method at different stages of oogenesis, initially, in the wild-type R-86 strain of Drosophila melanogaster after treatment with EI and EMS. The former which is known to induce dominant lethals in mature oocytes of the 14th stage with a high frequency was equally effective in inducing RLM in oocytes of different age and in oogonia. EMS which does not induce dominant lethals when used as vapour was shown to increase RLM frequency in mature fraction of oocytes (the 14A stage only). Similar type of different mutability was found in mutagen-sensitive strain mus-201G1 and in the control 3-4 strain having the same genetical background as mus mutation. Female germ cells of mus-201G1 strain appeared to have a higher mutability in the case of EI, though no differences in mutability between these strains after EMS treatment were registered. The data are discussed in view of the specificity of primer damages occurring as a result of comparable mutagens action and participation of different repair systems in elimination of these damages.     

An electron microscopic study of the interaction of bacterial intestinal microflora and rotavirus virions]

Transmission electron microscopy has revealed the capacity of rotaviruses for adsorption on Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis cells and the absence of such capacity with respect to Enterococcus faecalis, Lactobacillus casei and Edwardsiella tarda. Different degrees and a varying character of the adsorption of rotaviruses by the representatives of the opportunistic group of bacteria have been established, which may aggravate the course of rotavirus diarrhea due to the aggregation of viral particles. For the first time the phenomenon of the selective destructive adsorption of rotaviruses by E. coli indigenous strains M-17 and 33/29, typical representatives of normal enteric microflora, is described. This observation should be regarded as one of important biological mechanisms responsible for the protection of the body from rotavirus infection.     

Associations of the soil amoeba Hartmannella rhysodes with the bacterial causative agents of plague and pseudotuberculosis in an experiment]

Some aspects of relationships between soil ameba and the causative agents of plague and pseudotuberculosis, capable of forming natural associations, are considered. Ameba can phagocytose bacteria causing plague and pseudotuberculosis. Cases of the preservation of individual bacterial cells at the stationary phase and in precysts of amebae have been registered.