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Biomedical subjects

A D Dmitriev

Publications and source records attributed to A D Dmitriev.

At least 37 records · Page 2Linked to original sources
PubMed1989

[A decrease in the content of immunoreactive alpha- and gamma-endorphins in the blood and the suppression of their hypersecretion under the influence of dexamethasone in emotional stress in monkeys].

Daily administration of 12 mg of dexamethasone to monkeys during 10 days resulted in decrease of the levels of alpha- and gamma-endorphins and cortisol 7 days after the first injection. The titers of these peptides in plasma of monkeys. exposed to two hours of immobilization stress were elevated twice above basal levels. The maximum elevation took place 6 hours after the beginning of immobilization. This effect wasn't detected in monkeys, which received 12 mg of dexamethasone during 10 days.

Acute Disease↗
PubMed1988

[Monoclonal antibodies to alpha-endorphin effective in immunohistochemistry and immunoblotting].

Four mouse monoclonal antibodies (E11, A8, F8, H5) to alpha-endorphin have been produced. The antibodies bind 12.5, 20.6, 9.6, 6.6% of 125I-beta-endorphin and 35.5, 15.1, 12.8, 12.2% of 125I-gamma-endorphin; the binding of 125I-alpha-endorphin being taken for 100%. The binding of antibodies E11, A8, F8 and H5 to 125I-alpha-endorphin was 50% inhibited by unlabeled ligand in concentrations 5, 50, 30 and 35 nM respectively. Using tissue sections of rat pituitary it was shown that antibody E11 can be used for the localization of endorphin producing cells by immunofluorescence. The antibodies F8 and H5 effectively detected endorphin precursor proopiomelanocortin by immunoblotting.

Animals↗
PubMed1988

[Increased level of immunoreactive opioid peptides in the brain and adrenals of rats as affected by adaptation to physical loading].

The effect of long-term (7 weeks) swimming training on the content of beta-endorphin, met- and leu-enkephalins in various brain regions and adrenal glands has been studied in Wistar rats. It has been shown that the adaptation to exercise induced an increase in the content of opioid peptides in most of the brain regions and in adrenal glands. This increase in the level of opioid peptides seems to play an important role in the increase of the resistance to stress.

Adaptation, Physiological↗
PubMed1988

[Identification of pro-opiomelanocortin and its C-terminal fragments in the mammalian thymus].

Immunoreactive alpha-, beta-, gamma-endorphins and beta-lipotropin were detected in perfused calf thymus extracts at the following concentrations (fmol/mg) tissue, M +/- m): 1.32 +/- 0.08, 1.53 +/- 0.45, 0.0186 +/- 0.0022 and 0.741 +/- 0.157, respectively. It was demonstrated for all ligands tested that the synthetic peptide and increasing amounts of the extract cause a similar displacement of the corresponding 125I-peptide from its complex with specific antiserum. Using the immunoblotting technique with a highly specific antiserum to bovine beta-lipotropin, the extracts of calf thymus, rat thymocytes and bovine hypophysis were found to contain two polypeptides with Mr of 32 and 14 kD, whose mobility corresponds to that of proopiomelanocortin and beta-lipotropin.

Animals↗
PubMed1987

[The opioid component of the effect of the lacrimal glands on wound healing].

Naloxone partially inhibited skin wound contraction and completely blocked acceleration of wound healing in rats with stimulated lacrimal glands. Endorphins were detected in lacrimal glands. Alteration of functional activity of the lacrimal glands produces a considerable effect on pain sensitivity and endorphin blood concentration. Opioid peptides have a considerable effect on the functioning of the lacrimal apparatus and are involved in injury-induced reactions, regulating pain sensitivity, structural homeostasis and producing an anti-stress effect.

Animals↗
PubMed1986

[Detection of the pro-opiomelanocortin peptide fragments--beta-endorphin and ACTH--in the adrenals of rats and mice by immunohistochemistry].

Independent peptide fragments of pro-opiomelanocortin molecule, beta-endorphin and ACTH, have been detected immunohistochemically in the adrenal glands of rats and mice. Immunoreactive beta-endorphin and ACTH have been revealed in the adrenal medulla and reticular zone of the adrenal cortex. beta-endorphin and ACTH distribution patterns in adrenal sections were identical, which is indicative of the linked synthesis of these peptides in the adrenal gland. The data obtained suggest the existence of pituitary-independent mechanisms regulating corticosteroidogenesis in the adrenal gland, involving adrenal pro-opiomelanocortin fragments.

Adrenal Glands↗
PubMed1985

[Distribution of alpha-, beta- and gamma-endorphins in the forebrain and diencephalon of the rat brain (immunohistochemical study)].

The investigation performed by means of specific rabbit antisera is one of the stages for mapping peptides. This is necessary for revealing functional role of the endorphins in the CNS. The indirect method of Coons is applied in parallel series of frontal paraffin slices of the brain 10 mcm thick. Neurons containing alpha-, beta- and gamma-endorphins are localized in the same brain areas. These are structures of the palaeocortex (the prepiriform cortex and the diagonal area) and those of the hypothalamus (the supraoptic, arcuate, ventromedial, mammillary nuclei, anterior and posterior fields). Endorphinergic neural fibers run within composition of various conducting cerebral systems, such as the corpus collosum, fornix, internal and external capsules.

Animals↗
PubMed1985

[Bronchial asthma and endorphins].

The paper deals with the investigation of endorphin content in the blood of patients with asthma. The increase in alpha- and beta-endorphin concentration was shown to depend on the severity of clinical manifestations of infectious-allergic and atopic forms of bronchial asthma. This regularity was not observed for gamma-endorphin. The infectious-allergic form of asthma was characterized by drastic reduction in the content of all three endorphin types upon treatment with dexamethasone. The possible role of endorphin reactions in the pathogenesis of asthma is discussed.

Adolescent↗
PubMed1985

[Identification of pro-opiomelanocortin and the secretion of its peptide fragments in the adrenals of the bull].

Immunoreactive alpha-, beta- and gamma-endorphins and beta-lipotropin--C-terminal peptide fragments of pro-opiomelanocortin (POMC)--were discovered and measured by RIA in the bovine adrenal medulla and cortex. These peptides were also discovered in perfusates of the adrenal gland. POMC proper and some intermediate forms of its processing not differing in electrophoretic mobility from the respective molecular forms of hypophyseal POMC were identified in the medulla and cortex of the adrenals by the immunoblotting technique with the use of antiserum to beta-lipoprotein. It is concluded that POMC gene is expressed in the adrenal medulla and cortex and that as a result of POMC processing a noticeable amount of its peptide fragments is formed and secreted in adrenal cells. The authors thus suggest the presence of existence of the pituitary-unrelated mechanisms of adrenal function control with participation of POMC peptides synthesized in the adrenals.

Adrenal Glands↗
PubMed1985

[Changes in the opioid peptide content of the adrenals of rats during immobilization stress].

Radioimmunoassay was used to study variation in the content of opioid peptides (leu- and met-enkephalins) in rat adrenal glands at different stages of immobilization stress. The data obtained were correlated to the content of catecholamines (CA). It was discovered that during stress, the content of peptides noticeably increased, being independent of the main pool of CA in adrenal tissue.

Adrenal Glands↗
PubMed1984

[Effect of beta-endorphin on G-cells in rats with experimental duodenal ulcer].

Immunohistochemistry was used to study the changes in the number of G cells in the antral part of the stomach of rats (40 animals) with cystamine-induced duodenal ulcer treated with beta-endorphine. In the stomach of rats with cystamine-induced ulcer the number of G cells was discovered to be significantly increased, which was removed by an opioid peptide. Naloxone did not block the action of beta-endorphine. Thus, beta-endorphine changes the number of G cells, the drug action being not associated with opiate receptors.

Animals↗
PubMed1984

[Prevention of heart contractile disorders in experimental infarct by using preliminary adaptation to stress exposure and opioid peptides].

Preliminary adaptation to brief immobilization stresses was shown to reduce impairments of the contractile function of the left ventricle in an experimental myocardial infarction both under conditions of physiological rest and following the short blocking of the aorta. This protective effect is occasioned, along with other factors, by the prevention of the stressory damage to the non-ischemic portions of the heart. The same adaptation increased the levels of enkephalins and beta-endorphin in the cerebral and adrenal structures. The preliminary administration of beta-endorphin prior to the stimulation of an experimental infarction considerably prevented stressory disorders of the contractile function of the right atrium.

Adaptation, Physiological↗
PubMed1976

The influence of mutations upon the synthesis of RNA polymerase subunits in Escherichia coli cells.

The influence of mutations in structural genes of beta and beta subunits of RNA polymerase upon the synthesis of these subunits in E. coli cells have been investigated. An amber-mutation ts22 in the beta subunit gene decreases the intracellular concentration of this subunit and the rate of its synthesis. At the same time the concentration and the rate of beta subunit synthesis is increased. These suggest the compensatory activation of the RNA polymerase operon that takes place under the conditions of shortage of one of the subunits. Reversions as well as more effective suppression of ts22 amber mutation, achieved by streptomycin addition, substitution of su2 by sul, or by specific mutations, result in a rise of beta and drop of beta subunit concentration and synthesis in ts22 mutant. TsX missense-mutation in the beta subunit gene alters the properties of the enzyme increasing, at the same time, the concentration and the rate of synthesis of both beta and beta subunits, particularly at a nonpermissive temperature. This points to an inversely proportional relationship between the rate of synthesis of RNA polymerase subunits and the total intracellular activity of the enzyme. Extra subunits are rapidly degraded in ts22 and tsX mutants. The whole complex of our data and those of others suggest that the regulation of the synthesis of RNA polymerase subunits is accomplished by interaction of a negative and a positive mechanisms of regulation which include not only activators and repressors but the enzyme itself as well.

DNA-Directed RNA Polymerases↗