Effect of cortisol, its polymeric derivative and adenylate cyclase activators on the content of cyclic AMP in rat thymocytes

In has been shown that cortisol immobilized on polyvinylpyrrolidone (PVP-GC) affects cyclic AMP production stimulated by adenosine and isoproterenol in rat thymocytes. This effect of PVP-GC is specific for cortisol: antiglucocorticoid progesterone (at a concentration of 10(-5) M) inhibited completely the action of PVP-GC on the intracellular cAMP level. It is suggested that cortisol effect on cAMP production is one of the mechanisms of glucocorticoid hormone action in target cells.     

Neurogenic cholinergic dilation observed in isolated vessels of the skeletal muscles of cats (the caudal femoral artery)

Neuromediated behaviour of feline caudal femoral arteries was studied in vitro. Transmural stimulation of arteries, previously constricted by noradrenaline, caused an up to 58% relaxation of the induced tone. Atropine (10(-5) g/ml) blocked this response by 93%. The removal of endothelium did not affect the magnitude of the response. It is suggested that the caudal femoral artery is an example of a blood vessel which has muscarinic receptors located directly on its smooth muscles.     

The Role of the Vascular Factor in the Reorganization of Water Metabolism in Denervated Liver after Bacterial Endotoxin Poisoning

Intoxication with bacterial lipopolysaccharide (endotoxin) is accompanied by considerable rearrangements in the systems of blood microcirculation and water metabolism of the liver. These rearrangements are manifested as increased sinusoid area, changed total area of the cytoplasm and nuclei as well as the nucleocytoplasmic ratio in hepatocytes, increased content of total water in the organ, and changed magnetic relaxation properties (spin-lattice and spin-spin relaxation times). Preliminary parasympathetic denervation of the liver (vagotomy) changes the pattern of the organ response to bacterial endotoxin poisoning as indicated by the kinetics of studied morphological and biophysical parameters.     

Mechanism of action of N-acetylglucosaminyl-N-acetylmuramylalanyl-D-isoglutamine on the nonspecific anti-infection resistance of mice

The stimulating influence of glucose-containing muramyldipeptide (GMDP) on the nonspecific resistance of mice was shown to depend on the features of the pathogenesis of the infection. Thus, the intraperitoneal injection of GMDP increased the survival rate of mice infected with Escherichia coli, but had no stimulating effect on the resistance of the animals to Salmonella typhimurium natural infection in whose pathogenesis macrophages played an essential role. Experiments demonstrated that GMDP was capable of enhancing the ingestive function of macrophages, but did not increase their bactericidal activity with respect to this infection.     

The diagnosis of antileptospiral antibodies in human subjects by solid-phase immunoenzyme analysis

The possibility of using the enzyme-linked immunosorbent assay (ELISA) for the diagnosis of leptospirosis has been shown. This method has proved to be more simple and sensitive than the leptospiral microagglutination and lysis test. The data on obtaining genus-specific leptospiral antigens are presented. As revealed in this study, the antigens obtained by the complex treatment of microbial cells with ultrasound and detergents show the maximum activity in ELISA. The optimum parameters of the ELISA system for the diagnosis of leptospirosis have been established.     

Daphniopsis australis nov.sp. (Crustacea: Cladocera), a further daphniid in Australian salt lakes

Daphniopsis australis, a new species of cladoceran in Australian salt lakes, is described, and some brief comments on its distribution are given.     

Vitamin K-dependent gamma-carboxylation of the 1,25-dihydroxyvitamin D3 receptor.

It has been reported that vitamin K deficiency in the rat markedly increases the 1,25-dihydroxyvitamin D3 receptor (VDR) binding to DNA and that vitamin K-dependent gamma-carboxylation of endogenous substrates of the intestinal and renal cytosol, also containing VDR, sharply reduced that binding (Sergeev, I.N., and Spirichev, V.B. (1989) Nutr. Res. 9, 725-733). In the present study we have evaluated vitamin K-dependent 14CO2 incorporation to VDR quantitated by immunoprecipitation with anti-VDR monoclonal antibodies. The results obtained strongly suggest that VDR in vitro can undergo gamma-carboxylation in the presence of vitamin K1 and that 15-25% of Glu residues in the VDR are carboxylated in vivo. Taking into account our earlier findings, it is likely that the VDR gamma-carboxylation modulates its binding to DNA.     

Store-operated cationic channels in human myeloid leukaemia K562 cells

Using the whole-cell patch clamp technique, single channels operated by intracellular Ca(2+)-store depletion were first revealed in human myeloid leukaemia cells K562. A single store-operated channel could be detected in divalent-free extracellular solutions with Na+ as a permeant ion, and intracellular solutions with strong Ca(2+)-helating agent with some delay after whole-cell formation. Addition of inositol-1,4,5-triphosphate to the pipette solution resulted in a significant decrease of this latency. These channels had a conductance of 29 pS, and were inhibited by low concentration of external Ca2+. Our results enable us to assume that the revealed channels are calcium release-activated calcium channels, operated by Ca2+ depletion of endoplasmic reticulum.     

The effect of intracerebral mesenchymal stem cells transplantation on the density of microvascular network of the pial matter of the rat brain cortex

Using a TV installation for studying the microcirculation (with 30-160-fold magnification), the density of microvascular network in the pia matter of the rat brain sensomotor cortex was determined after intracerebral transplantation of mesenchymal stem cells (MSC) or (as control) of the MSC cultivation nutrition medium, or of saline. The results have shown that intracerebral transplantation does not change density of microvascular network in the pia mater of the ipsilateral hemisphere. Transplantation of the MSC led to a 1.8-fold increase of density of the pia matter of the contralateral hemisphere as compared with control animals; the number of arterioles in the same zone was 2.5-fold higher than in intact rats.     

Inactivation of viruses in bubbling processes utilized for personal bioaerosol monitoring

A new personal bioaerosol sampler has recently been developed and evaluated for sampling of viable airborne bacteria and fungi under controlled laboratory conditions and in the field. The operational principle of the device is based on the passage of air through porous medium immersed in liquid. This process leads to the formation of bubbles within the filter as the carrier gas passes through and thus provides effective mechanisms for aerosol removal. As demonstrated in previous studies, the culturability of sampled bacterium and fungi remained high for the entire 8-h sampling period. The present study is the first step of the evaluation of the new sampler for monitoring of viable airborne viruses. It focuses on the investigation of the inactivation rate of viruses in the bubbling process during 4 h of continuous operation. Four microbes were used in this study, influenza, measles, mumps, and vaccinia viruses. It was found that the use of distilled water as the collection fluid was associated with a relatively high decay rate. A significant improvement was achieved by utilizing virus maintenance fluid prepared by using Hank's solution with appropriate additives. The survival rates of the influenza, measles, and mumps viruses were increased by 1.4 log, 0.83 log, and 0.82 log, respectively, after the first hour of operation compared to bubbling through the sterile water. The same trend was observed throughout the entire 4-h experiment. There was no significant difference observed only for the robust vaccinia virus.