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Biomedical subjects

G I Chipens

Publications and source records attributed to G I Chipens.

85 records · Page 5Linked to original sources
PubMedDate not supplied

[Primary structure and species specificity of immunopoietins].

A model involving quasicyclization of protein molecules following the stepwise reactions of limited proteolysis was developed. On the basis of the model new active sites were detected in immunoglobulins of various species as well as chemical synthesis of the sites was carried out. The new group of the substances was designated as immunopoietins. The primary structure of various species immunoglobulins was analyzed and evolutional stability of the immunopoietin structure was shown.

Amino Acid Sequence↗
PubMedDate not supplied

[New immunostimulants of the nature of peptide-proteins].

Synthesis and biological activity of cyclic derivatives of linear peptide bioregulators are considered. Development of polyfunctional quasicyclic substances, stabilized by means of intramolecular ionic, hydrogen and other bonds, exhibiting specific interaction with receptors, is the universal principle in function of natural ligands.

Adjuvants, Immunologic↗
PubMedDate not supplied

[Relation between the effects of the memory neuromodulator arginine-vasopressin and the levels of activity of the serotonin-, dopamine- and noradrenergic systems of the brain].

The effect of vasopressin on learning, habituation and habit recovery in rat before and after electrolytic ablation of locus coeruleus, nuclei dorsalis et medialis raphe and pars compacta substantiae nigrae was studied by behavioural methods. The rats were learned with positive reinforcement in a T-shaped maze and with negative reinforcement in a U-shaped maze. It was found that improvement of trace consolidation and acceleration of learning were in many cases dependent on the activity level of the dophaminergic, noradrenergic and to a lesser degree on that of serotoninergic brain systems.

Animals↗
PubMedDate not supplied

[Determination of blood serum renin activity in nephrogenic hypertension].

The results of determination of blood plasma renin activity (PRA) in patients with nephrogenic hypertension are presented. A conclusion was drawn that PRA determination in the venous blood of each kidney separately was of greater importance for the diagnosis and solution of the problem of surgical tactics in patients with nephrogenic hypertension than PRA determination in the peripheral venous blood.

Adult↗
PubMedDate not supplied

[An alternative model of structural organization of the ternary complex antigen-protein MHC II-TCR].

An alternative model of organization of the structure of ternary complex "antigen-molecule" of the main complex of histocompatible class II (MHC II)--antigenic receptor of T-cells (TCR) is suggested. In contrast to the already developed ones the new model foresees TCR interaction with only one (beta)-chain of the molecule MHC (II), with its surface site having the structure of alpha-spiral. The second (alpha)-chain of the molecule MHC II performs only antigen-binding and supporting function. According to the structure of the code of amino acids interaction a comparative analysis of the roots (bases of the second nucleotides) of amino acid codons of fragments of alpha-, beta-, and gamma-invariant chains of MHC II, as well as some antigens and immunoregulators. An expressed similarity of the structures of spiral fragment of beta- and gamma-chains of MHC II both between themselves and with certain antigens and natural immunoregulators.

Amino Acid Sequence↗
PubMedDate not supplied

[Structural similarity of the active sites of major histocompatibility complex class I proteins and ubiquitin].

With the help of a new method of protein primary structures analysis, i.e. CAACRA (comparative amino acid codon root analysis) a marked structural similarity of the MHC class I protein active sites and ubiquitin alpha-helix has been revealed. Using the CAACRA a periodicity of ubiquitin primary structure has been shown. Ubiquitin molecule consists of 4 repeat units.

Amino Acid Sequence↗
PubMedDate not supplied

[Structure and organization of class I interferon molecules].

The regular structure of class I interferon molecules was proposed using the new method of protein structure investigation--the comparative analysis of amino acids codon roots. It was found out that IFN-alpha and IFN-omega molecules are formed of 5 repeats. Each repeat can be divided into two parts or blocks with regular (alpha-spiral, block A) and irregular (parts of molecules between alpha-spirals, block B) structures. Localization of blocks A and B in IFN-alpha molecules has good correlation with the models of secondary structure organization of IFN-alpha. It is supposed that such a structure of IFN molecules is formed in the evolution process as a result of multiplication of IFN primary gene.

Amino Acid Sequence↗
PubMedDate not supplied

[Specific antagonism between angiotensin II and several of its analogs].

The authors studied comparatively the properties of two angiotensin II analogues, a new compound (1-hydantoin acid, 5-valine, 8-alanine)-angiotensin II (compound III) and (1-asparagine, 5-valine, 8-alanine)-angiotensin II (compound II), as of the myotropic action of angiotensinamide (these experiments were conducted on the rat isolated ascending colon); pressor action of the hormone was investigated in experiments on anesthetized rats. A competitive character of the antagonism--within the range of low concentrations of the analogues--10(-10)--10(-9) M/l--was revealed in vitro. No antagonism was expressed against the nonspecific myotropic agents--acetylcholine and bradykinin. In vivo compounds II and II manifested the antagonistic action against angiotensinamide beginning from the doses of 100 and 50 gamma/kg, respectively.

Angiotensin II↗