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Biomedical subjects

N F Miasoedov

Publications and source records attributed to N F Miasoedov.

At least 37 records · Page 2Linked to original sources
PubMed1983

[Labeling of steroids with tritium].

Conditions have been elaborated for the tritium labeling of some steroids to a molar activity of the order of 1 TBk/mol by heterogeneous catalytic isotopic exchange. For steroids without a keto group, isotopic exchange with gaseous tritium is most effective in neutral solvents, whereas for steroids with a keto group an alkaline medium is preferable. At certain pH values it was possible to void hydrogenation of the double bonds in the compounds.

Chemical Phenomena↗
PubMedDate not supplied

[A synthesis of tritium-labeled olanzapine].

A synthesis of olanzapine, 2-methyl-10-(4-methyl-1-piperazinyl)-4H-thieno[2,3-b][1,5]benzodiazepine was carried out, and the conditions for its tritium labeling were optimized, to get a tritium-labeled olanzapine preparation with molar radioactivity of 12 Ci/mmol.

Benzodiazepines↗
PubMedDate not supplied

[Semax and selank inhibit the enkephalin-degrading enzymes from human serum]].

A dose-dependent effect of synthetic heptapeptides Semax (Met-Glu-His-Phe-Pro-Gly-Pro) and Selank (Thr-Lys-Pro-Arg-Pro-Gly-Pro) on the enkephalin-degrading enzymes of human serum was demonstrated. The inhibitory effects of Semax (IC50 10 microM) and Selank (IC50 20 microM) are more pronounced than those of puromycin (IC50 10 mM), bacitracin, and some other inhibitors of peptidases. Beside the heptapeptides, their pentapeptide fragments also possessed an inhibitory effect; tri-, tetra-, and hexapeptide fragments did not display such an effect. As the above enzymes take part in degradation of not only enkephalins but also other regulatory peptides, it can be assumed that one of the mechanisms of biological activity of Semax and Selank is related to this inhibitory activity of theirs.

Adrenocorticotropic Hormone↗
PubMedDate not supplied

[Species and tissue distribution specificity of proteins binding 16alpha,17alpha-cycloalkane derivatives of progesterone].

The binding of [3H]progesterone and [3H] 16 alpha,17 alpha-cycloalkanoprogesterones to proteins from rat, rabbit, and human uteri and other organs was studied. We found that 16 alpha,17 alpha-cycloalkanoprogesterone derivatives display affinities for the uterine progesterone receptors comparable with that of the natural hormone and no substantial species differences in the affinity. Rabbit uterus was found to have no proteins distinct from the progesterone receptor that specifically bind [3H] 16 alpha,17 alpha-cycloalkanoprogesterones. At the same time, in the human uterus, we found another protein that binds some of these progesterone derivatives; it turned out to be similar to the protein from rat uterus. A similar protein with the same selectivity and affinity for steroids was also found in rat and human kidneys. Blood serum, liver, lung, and a number of other tissues were found to contain a protein of the third type that binds the same 16 alpha,17 alpha-cycloalkanoprogesterones and exhibits submicromolar Kd values for these steroids and a very low affinity for progesterone. We speculated that the introduction of a bulky substituent adjacently to the 17 beta-side chain of progesterone could result in a change in the general biodynamics of the derivative including its transport, uptake, and accumulation in tissues, which may determine the selectivity of its effect.

Animals↗
PubMedDate not supplied

[Leu-enkephalin homogeneously labeled with tritium in studying the Selank inhibiting effect on the enkephalin-degrading enzymes of human plasma].

A method of analysis of enkephalinase activity in blood plasma based on the application of Leu-enkephalin generally labeled with tritium at all its amino acid residues was developed. The method allows the simultaneous estimation of activity of several peptidases in microquantities of tissues. [G-3H]Leu-enkephalin was prepared by the method of solid phase catalytic isotope exchange (120 Ci/mmol) and subjected to proteolysis by the treatment with blood plasma. The resulting radioactive metabolites were separated by HPLC in the presence of the mixture of unlabeled fragments of Leu-enkephalin as internal standards. It was shown that aminopeptidases, dipeptidylaminopeptidases, and dipeptidylcarboxypeptidases respond for approximately 80%, 2%, and 10% of the total enzymatic activity, respectively. The new pathway of degradation of Leu-enkephalin by carboxypeptidase that provides for approximately 6% of the total enkephalin-degrading activity was discovered. Bestatin was shown to predominantly inhibit aminopeptidases and carboxypeptidases, whereas Selank is more specific for carboxypeptidases and dicarboxypeptidases. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2004, vol. 30, no. 3; see also http://www.maik.ru.

Aminopeptidases↗
PubMedDate not supplied

[The binding of Semax, ACTH 4-10 heptapeptide, to plasma membranes of the rat forebrain basal nuclei and its biodegradation].

The binding characteristics of the peptide Semax (Met-Glu-His-Phe-Pro-Gly-Pro) to plasma membranes of basal nuclei of the rat forebrain and the dynamics of its degradation during its incubation with these membranes were studied. Binding of the homogeneously labeled [G-3H]Semax was shown to be time-dependent, specific, and reversible. Specific binding of the heptapeptide depended on calcium ions and was characterized by the dissociation constant of the ligand-receptor complex Kd = 2.41 +/- 1.02 x 10(-9) M and by the concentration of binding sites Bmax = 33.5 +/- 7.9 x 10(-15) mol/mg of protein. A method of studying Semax biodegradation in the presence of plasma membranes of rat brain was developed. It is based on the use of the peptide homogeneously labeled with tritium and on an HPLC analysis with UV detection at 220 and 254 nm of the peptide fragments formed. The half-life of Semax in the presence of the plasma membranes was demonstrated to be longer than 1 h. Dipeptidylaminopeptidases are considered to be the main enzymes responsible for its biodegradation; they successively cleave Semax to the HFPGP pentapeptide and the PGP tripeptide. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2004, vol. 30, no. 3; see also http://www.maik.ru.

Adrenocorticotropic Hormone↗
PubMedDate not supplied

[Kinetics of Semax penetration into the brain and blood of rats after its intranasal administration].

The radioactive peptide analogue Semax corresponding to the ACTH(4-10) sequence (Met-Glu-His-Phe-Pro-Gly-Pro) with a molar radioactivity of 56 Ci/mmol labeled with tritium at the C-terminal Pro was prepared. The labeled peptide was used for studying the kinetics of Semax penetration into rat brain and blood after its intranasal administration (50 microg/kg, 20 microl of solution) to nonbred white rats of body mass 200-250 g. It was demonstrated that 0.093% of the total introduced radioactivity per gram can be found in the rat brain 2 min after the administration, 80% of this radioactivity belonged to Semax, and the rest, to its metabolites. The peptide undergoes rapid enzymatic degradation, with the tripeptide Pro-Gly-Pro prevailing in biological samples relative to the total content of Semax and its metabolites.

Administration, Intranasal↗
PubMedDate not supplied

[Enzymatic synthesis of beta-NAD+ selectively marked with tritium at adenine and its use for determining the activity of poly(ADP-ribose) polymerase].

A method of preparation of tritiated beta-HA [symbol: see text]+ from (adenine-2,8-(3)H)ATP and nicotinamide mononucleotide is suggested. This method is based on the baker's yeast (Saccharomyces cerevisiae) enzyme nicotinamide nucleotide adenylyltransferase. Experimental conditions for a nearly complete conversion of labeled ATP to NAD were determined. The tritiated NAD prepared by this method can be used in the quantitative assay of the chromatin enzyme poly(ADP-ribose) polymerase.

Adenine↗
PubMedDate not supplied

[Gene c-Fos expression in brain of rats resistant and predisposed to emotional stress after intraperitoneal injection of the ACTH(4-10)analog--semax].

The effect of the ACTH(4-10) analog Semax on immediate early gene c-Fos expression was studied in Wistar rats with high and low resistance to emotional stress under the usual conditions and during psychoemotional loading. Fos-immunoreactive cells in the were counted automatically with the help of a computer. It was shown that under the usual conditions the intraperitoneal Semax injection induced immediate early gene c-Fos expression in the lateral septal region in rats predisposed to emotional stress and in the paraventricular hypothalamus in rats of both groups. Preliminary Semax injection decreased the stress-induced c-Fos expression in the paraventricular hypothalamus and medial septum in rats predisposed to emotional stress and tended to reduce the number of stress-induced c-Fos-immunopositive cells in the lateral septum and basolateral amygdala in both groups of animals. The obtained data suggest that Semax differently affects the immediate early c-Fos gene expression in the brain of rats resistant and predisposed to emotional stress and this effect reflects the antistressor properties of the regulatory peptide.

Adrenocorticotropic Hormone↗
PubMedDate not supplied

[Changes in beta-casomorphine-7 effect on behavior of albino rat pups in postnatal development].

The analgetic effect of heptapeptide beta-casomorphine-7 in newborn albino rats (20 mg/kg, i.p.) was recorded already 14 days after birth in the "hot plate" test. The first signs of a possible influence of the peptide on motor activity were observed only at the age of 28 days. They are expressed in impairment of motor coordination and change in locomotion level ("Opto-Varimex" test). The obtained evidence probably reflect the processes of discrete maturation of different components of the opioid system of the rat brain.

Analgesics, Opioid↗
PubMedDate not supplied

[Dermorphins--a natural opioids with unique primary structure that determines their biological specificity].

Based on the authors' and published data, the spectrum of biological activities of dermorphins was theoretically analyzed for the first time from the viewpoint of specific structural features of their molecule that determine selective affinity to mu-opiate receptors. It was shown that specific distribution of dermorphins and corresponding opiate receptors in tissues and organs, especially in the CNS structures, determines the role of dermorphins in the regulation of functions of the most important physiological systems.

Analgesics, Opioid↗
PubMedDate not supplied

[Effect of dermorphin analogs on thermoregulation of rats under various thermal conditions].

We studied the influence of dermorphin (dermorphin) analogs with stereochemical modification of the amino acid residue proline in position 6 (Pro6), Tyr-D-Ala-Phe-Gly-Tyr-Hyp-Ser-NH2, Tyr-D-Ala-Phe-Gly-Tyr-[D-Pro]-Ser-NH2, Tyr-D-Ala-Phe-Gly-Tyr-[dehydro-Pro]-Ser-NH2, and Tyr-D-Ala-Phe-Gly-Tyr-[D-dehydro-Pro]-Ser-NH2, after their intraperitoneal injection at 0.5 mg/kg dose in the cold (4-7 degrees C), thermoneutral (27-28 degrees C), and hot (31-33 degrees C) environment. Stereochemical modifications of amino acid residue Pro6 proved to induce specific changes in the thermoregulatory effect of the peptide. Substitution of DPro6 for Pro6 has the most dramatic consequences: it considerably attenuates the thermoregulatory effect of dermorphin in the cold environment, cancels it in the hot environment, and inverts the dermorphin-specific thermoregulatory response in thermoneutral conditions. The data obtained indicate the important role of Pro6 residue in realization of this physiological activity of dermorphins.

Animals↗
PubMedDate not supplied

[Effect of structural changes of Pro6 in dermorphin molecule on its antinociceptive activity].

We studied effect of dermorphin (H-Tyr-DAla-Phe-Gly-Tyr-Pro-Ser-NH2) and its analogs with modified amino acid residue proline in position 6, H-Tyr-DAla-Phe-Gly-Tyr-[DPro]-Ser-NH2, H-Tyr-DAla-Phe-Gly-Tyr-[dehydro-Pro]-Ser-NH2, and H-Tyr-DAla-Phe-Gly-Tyr-[D-dehydro-Pro]-Ser-NH2, on nociception in the tail-flick and hot plate tests after intraperitoneal injection. Replacement of LPro with the stereoisomer DPro as well as Pro dehydration (LdHPro) was shown to increase antinociceptive activity. Replacement of LdHPro with DdHPro cancelled the activity in the tail-flick test. All three dermorphin analogs retained antinociceptive activity in the hot plate test; however, the effect of dermorphin was more pronounced.

Analgesics↗
PubMedDate not supplied

[Highly stable regulatory oligopeptides: experience and applications].

The most stable regulatory peptides (RP) including the new family of RP (glyprolines) and derivatives of hybrid peptide MEHFPGP are characterized. High ability of glyprolines to penetrate into the blood-stream through the gastrointestinal tract is demonstrated. Antiulcer, antithrombotic and antidiabetic activities of glyprolines were discovered in experiments on white rats. The activity of oligopeptides PGP, PG and GP is compared. Mechanisms of glycoprolines activities and feasibility of their administration with connective tissue food proteins are discussed. Thus, glyprolines are perspective drugs for treatment of gastric ulcer, correction of hemostasis and thrombosis suppression prepared for preclinical trial.

Adrenocorticotropic Hormone↗