Study of Development of Function of Kidneys and Their Regulation on the Background of Pathological Process

By the example of reabsorption of sodium ions in kidney, it is shown that this process, alongside with establishment of the system of osmotic concentration, plays the key role in evolution of renal function. There is shown a similarity of tendencies of changes of the total sodium ion reabsorption in children’s kidney in the process of development and in a series of representatives of various vertebrate classes. An opposite tendency is revealed during the kidney dysfunction produced by chronic renal failure. At all stages of postnatal ontogenesis in healthy children and in adults, kidney maintains the same parameters of the blood serum ion composition and osmolality. A new approach to study evolution of functions is proposed, which is based on a combination of two L.A. Orbeli’s methods—ontogenetic and clinical, by the example of study of renal function and its regulation during development of a pathological process on the background of formation of function in postnatal ontogenesis. When using such approach in children with nocturnal enuresis, significance of autacoids in regulation of urine formation is established. In the case of acute pneumonia in children, a possibility of extrapituitary production of vasopressin-like substances in lungs is shown. In norm, in postnatal ontogenesis of healthy children, in regulation of renal functions and of diuresis system, effects of efferent nerves and hormones (vasopressin) dominate, while significance of autacoids is minimal. But at a dysfunction produced by a pathological process, a change of ratio of activities of these regulatory systems is revealed. The obtained data indicate importance of the clinical and experimental methods proposed by L.A. Orbeli in analysis of evolution of renal functions and study of the nature of regulations. A combination of several methods of evolutionary physiology in one study allows revealing new mechanisms underlying regulation of function and promotes formation of concepts about regularities of evolution of functions.__________Translated from Zhurnal Evolyutsionnoi Biokhimii i Fiziologii, Vol. 41, No. 3, 2005, pp. 277–284.Original Russian Text Copyright © 2005 by Kuznetsova, Natochin.     

Collagen type I fibril packing in vivo and in vitro

Reviewed are works concerning the mechanisms of collagen (type I) fibril packing and the influence of macromolecular structure and physicochemical parameters of the medium on the process.     

Action of pilocarpine on the normal frog heart and in pathology

Experiments on frogs were performed to examine the effect of the M-cholinomimetic pilocarpine on the heart. It was discovered that at concentrations of 10(-15)--10(-5) g/ml pilocarpine exerted only an adverse chronotropic effect on the perfused heart. When applied at a concentration of 10(-4) g/ml the drug produced a negative as well as a positive chronotropic effect. The latter occurred spasmodically (without progressive rise in the heart rate) in association with a slow heart rate. In some experiments such effects were preceded by a certain deceleration of the heart. In experiments with positive chronotropic effects, arrhythmias and sinoatrial dissociation were observed sometimes. Experiments with recording of the electrograms of the sinuses and lower parts showed that such effects were caused not by pacemaker acceleration but by the removal of the blockade of conduction, between the pacemaker and the atria. As far as the pacemaker is concerned, pilocarpine exerted only a negative chronotropic effect.     

Stereospecificity of the effect of flupenthixol isomers on the substrate inhibition of brain tyrosine hydroxylase

Stereospecificity of the effect of neuroleptics on substrate inhibition of isolated brain tyroxine hydroxylase is shown. Flupentixole cis-isomer eliminates substrate inhibition of the enzyme. The effect is concentration-dependent and is well marked within the tyrosine concentration range 10-6-10-4 M. Flupentixole trans-isomer in the same concentrations has no effect on substrate inhibition of tyrosine hydroxylase. In the presence of cis-flupentixole, the reaction rate plotted against tyrosine concentration is a hyperbole with a plateau at 160-360 microM tyrosine. In the presence of trans-isomer, as in the control sample, the relationships between the reaction rate and tyrosine concentration are depicted by a curve with a maximum (at 110-140 microM tyrosine). Like ftorphenazine, flupentixole isomer fails to eliminate the inhibitory action of alpha-methyl paratyrosine, which indicates the interaction of neuroleptics with the tyrosine-binding site of the enzyme molecules in the noncatalytic centrer. It is suggested that the interaction of the neuroleptics with the regulatory area of tyrosine hydroxylase might by important in the molecular mechanism of their action.     

New data on the type of structural changes in DNA of simian adenovirus SA7 microinjected into mouse zygotes

The structure of the transgene has been analysed in a new series of experiments on the transfer of adenovirus SA7 DNA into the mice zygotes by microinjection technique. The previous data on SA7 DNA elimination from the genomes of different organs (sceletal muscles, heart, tail) have been confirmed and detailed for the F0 and F1 generations of transgenic animals. The left end of adenoviral genome has been shown to be predominantly transfered after microinjections of SA7 DNA into the mice zygotes.     

Phylogenetic Analysis of Sequences of the 12S and 16S rRNA Mitochondrial Genes in the Family Bovidae: New Evidence

The phylogeny of the family Bovidae has been inferred from our data on the 12S and 16S rRNA mtDNA gene sequences and from the results of other authors. A considerable (2460 bp) length of the analyzed fragments of these conserved genes and the use of different methods of cladogram construction allowed us to verify the systematic position of the genera Saiga, Pantholops, Procapra, and Oreamnos. Saigas were shown to be phylogenetically far closer to gazelles than black-tailed gazelles and pygmy antelopes. In general, the genetic analysis data are in agreement with the results of morphological studies.