PubMed Health⌕ Search

Biomedical subjects

A N Petrov

Publications and source records attributed to A N Petrov.

At least 19 recordsLinked to original sources
PubMed2005

In search of the electron electric dipole moment: relativistic correlation calculations of the P,T-violating effect in the ground state of HI+.

We report the first results of ab initio relativistic correlation calculation of the effective electric field on the electron, E(eff), in the ground state of the HI+ cation. This value is required for interpretation of the suggested experiment on the search for the electron electric dipole moment. The generalized relativistic effective core potential, Fock-space relativistic coupled cluster with single and double cluster amplitudes (RCC-SD), and spin-orbit direct configuration interaction (SODCI) methods are used, followed by nonvariational one-center restoration of the four-component wave function in the iodine core. The RCC-SD value is E(eff) = 0.345 x 10(24) Hz/e cm and SODCI study gives E(eff) = 0.336 x 10(24) Hz/e cm (our final value). The structure of chemical bonding in HI+ is clarified, and a significant deviation of our value from that of Ravaine et al. [Phys. Rev. Lett. 94, 013001 (2005)] is explained.

Journal Article↗
PubMed2002

Calculation of P, T-odd effects in 205TlF including electron correlation.

A method and codes for two-step correlation calculations of heavy-atom molecules have been developed, employing the generalized relativistic effective core potential (GRECP) and relativistic coupled cluster (RCC) methods at the first step, followed by nonvariational one-center restoration of proper four-component spinors in the heavy cores. Electron correlation is included for the first time in an ab initio calculation of the interaction of the permanent P,T-odd proton electric dipole moments with the internal electromagnetic field in a molecule. Inclusion of electron correlation by GRECP/RCC has a major effect on the P,T-odd parameters of 205TlF, decreasing M by 17% and X by 22%.

Journal Article↗
PubMed2001

Clinical and institutional aspects of antidote therapy in Russia.

The problem of antidote application for treatment of acute poisoning is related to epidemiology and characterization of poisoning cases, and possibilities for supplying antidotes to health care institutions. To investigate the situation in Russia we have analyzed reports by poisoning treatment centers for 1997-1999, comparison of medical aid standards for poisoning treatment in Russia with WHO recommendations. Acute poisoning pattern varies in different regions. Particularly, poisoning pattern in large cities in European Russia and the Urals is dominated by pharmaceuticals (up to 63.1%). Pesticide and insecticide poisoning cases do not exceed 1 to 2%, metal compounds and methemoglobin forming poisons (below 1% in each group). Antidotes are used in Russia in line with the recommendations adopted in international toxicological practice. The most actual are antagonists of opiates and benzodiazepines, physostigmine, atropine, pyridoxine, antagonists of beta-adrenergic blockers, activated charcoal. Such antidotes as DMPS (Unithiol), N-acetylcysteine, methylene blue, amyl nitrite (or sodium nitrite), complex formers of EDTA group are also included in the list of specific agents. The main problem is that some important antidotes are currently not produced in Russia. The Ministry of Health of the Russian Federation is taking efforts to launch production of some previously known and also newly developed important antidotes.

Alcoholism↗
PubMed2000

Mapping the functional domains of elongation factor-2 kinase.

A new class of eukaryotic protein kinases that are not homologous to members of the serine/threonine/tyrosine protein kinase superfamily was recently identified [Futey, L. M., et al. (1995) J. Biol. Chem. 270, 523-529; Ryazanov, A. G., et al. (1997) Proc. Natl. Acad. Sci. U.S.A. 94, 4884-4889]. This class includes eukaryotic elongation factor-2 kinase, Dictyostelium myosin heavy chain kinases A, B, and C, and several mammalian putative protein kinases that are not yet fully characterized [Ryazanov, A. G., et al. (1999) Curr. Biol. 9, R43-R45]. eEF-2 kinase is a ubiquitous protein kinase that phosphorylates and inactivates eukaryotic translational elongation factor-2, and thus can modulate the rate of polypeptide chain elongation during translation. eEF-2 was the only known substrate for eEF-2 kinase. We demonstrate here that eEF-2 kinase can efficiently phosphorylate a 16-amino acid peptide, MH-1, corresponding to the myosin heavy chain kinase A phosphorylation site in Dictyostelium myosin heavy chains. This enabled us to develop a rapid assay for eEF-2 kinase activity. To localize the functional domains of eEF-2 kinase, we expressed human eEF-2 kinase in Escherichia coli as a GST-tagged fusion protein, and then performed systematic in vitro deletion mutagenesis. We analyzed eEF-2 kinase deletion mutants for the ability to autophosphorylate, and to phosphorylate eEF-2 as well as a peptide substrate, MH-1. Mutants with deletions between amino acids 51 and 335 were unable to autophosphorylate, and were also unable to phosphorylate eEF-2 and MH-1. Mutants with deletions between amino acids 521 and 725 were unable to phosphorylate eEF-2, but were still able to autophosphorylate and to phosphorylate MH-1. The kinases with deletions between amino acids 2 and 50 and 336 and 520 were able to catalyze all three reactions. In addition, the C-terminal domain expressed alone (amino acids 336-725) binds eEF-2 in a coprecipitation assay. These results suggest that eEF-2 kinase consists of two domains connected by a linker region. The amino-terminal domain contains the catalytic domain, while the carboxyl-terminal domain contains the eEF-2 targeting domain. The calmodulin-binding region is located between amino acids 51 and 96. The amino acid sequence of the carboxyl-terminal domain of eEF-2 kinase displays similarity to several proteins, all of which contain repeats of a 36-amino acid motif that we named "motif 36".

Amino Acid Sequence↗
PubMed1991

[The proliferative activity of stomach cancer and evaluation of its individual radiosensitivity].

An indirect immunofluorescent method with polyclonal antibodies to thymidine was used to assess the proliferative activity (PA--percent of cells in the S-phase of the cell cycle) of 79 stomach tumors from primary cancer patients. Stomach cancer PA was shown to vary from 0.1 to 69.7%. PA did not depend either on a tumor size or a degree of the involvement of regional lymph nodes. The mean PA of well-differentiated adenocarcinoma was slightly lower (14.9 +/- 4.7%) than that of low differentiated ones. Of 79 patients a tumor process was interpreted as a resectable one in 62. They were given preoperative irradiation at a total focal dose of 36 Gy followed by operation. In addition to initial investigation PA in tumor biopsy specimens was assessed after delivering a dose of 12 Gy. PA changes at the beginning of a course of irradiation were compared with a degree of a radiation injury of tumor tissue after a course of irradiation was discontinued in 32 (explorative laparotomy was performed in 30). It was shown that tumor radioresistance could be predicted in unchanged PA indices of their increase at the beginning of a course of irradiation with the probability of 95%.

Adenocarcinoma↗
PubMed1990

[Approaches to predicting the reaction of human tumors to radiotherapy].

Immunofluorescent method using anti-thymidine antibodies was employed to assess proliferative activity of 217 human tumors including oropharyngeal, esophageal, gastric, rectal and lung cancer. The activity was evaluated before and, in 38 neoplasms, in the course of radiotherapy. It was shown that changes in the proliferative activity of oropharyngeal and gastric malignancies observed early in the course of radiation treatment may serve for predicting response.

Esophageal Neoplasms↗
PubMed1989

[Evaluation of the proliferative activity of malignant human tumors by an indirect immunofluorescent method using antithymidine antibodies].

155 samples of human malignant tumours were studied by the immunofluorescent method and the antithymidine antibodies index-labelling (IL--% of tumour cells in the S-phase). Wide individual variability (0.1-73%) of IL of the studied tumours was shown to be present and to be preserved inside the tumours which were homogeneous by the histological type and developmental stage. A correlation between the labelling index and tumour differentiation in the gastric adenocarcinoma is observed.

Adenocarcinoma↗
PubMed1978

[Effect of cholinolytic and adrenergic blocking preparations on rat erythrocyte resistance to hypo-osmotic hemolysis].

The influence of central cholinolytics and adrenoblocking drugs on the hemolysis of rat erythrocytes in the hypoosmotic buffer was studied in vitro. At pH 7.4 in a concentration of 10(-4) M central cholinolytics ethyl-dipracil, diphacil, pediphen, tropacin, and beta-adrenoblocking agent propranolol protected the erythrocytes from hemolysis most intensively. The central M-cholinlytics amizyl, glypin, and alpha-adrenoblocking agents purroxan, sympatholytin, phentolamin were less active. The antihemolytic effect of drugs reached the maximum in the course of 30 minutes, and was maintained for several hours. The protection of erythrocytes from hemolysis by drugs containing tertiary nitrogen was greater. Prevention of the hypoosmotic hemolysis pointed to the stabilization of the erythrocyte membrane by the preparations examined. In the mechanism of action of the central N-cholinolytics and beta-adrenoblocking drugs it is necessary to consider the possibility of stabilization of the membrane formations containing no synaptic contacts.

Adrenergic alpha-Antagonists↗
PubMed1977

[Effect of amizil and arecoline on the activity of Na, K-ATP-ase and concentration of Na+ and K+ ions in rat brain].

A study was made of the activity of Na, K-ATP-ase and the Na+ and K+ content in the brain of rats with the action of arecoline and amizyl. Both arecoline and amizyl increased the Na, K-ATP-ase activity. This could be associated with the changes in the redistribution of the Na+ and K+ ions in the nerve cell. Arecoline proved to cause changes in the electrolyte distribution by the depolarization type, whereas amizyl--by the type of hyperpolarization of the nerve cell membrane.

Adenosine Triphosphatases↗
PubMed1977

[Rat brain Mg2+-ATPase activity and Ca2+ and Mg2+ concentration in the presence of amizil and arecoline].

The effect of benactyzine (the central cholinolytic) in a dose of 40 mg/kg and arecoline (cholinomimetic) in a dose of 2.5 mg/kg on the activity of Mg2+-dependent ATP-ase and the content of Ca2+ and Mg2+ ions in the brain was studied in rats. It was shown that benactyzine and arecoline evoked a biphasic change in the activity of the enzyme and the electrolyte content. A conclusion was drawn that the enzyme inhibition was connected with the accumulation of Ca2+ ions in the brain tissue, whereas its inhibition--with the Mg2+ ion accumulation. It is supposed that throught these effects benactyzine and arecoline influenced the release and retention of the neuromediators in the tissue depot.

Adenosine Triphosphatases↗
PubMed1976

[Distribution of the adrenoblocking drug pyrroxan in the bodies of white rats].

The distribution of adrenoblocking drug pyrroxan in the blood plasma and different organs of albino rats had been studied. A rapid appearance of pyrroxan in the brain liver, kidneys, and other organs was shown; its selective accumulation in the hypothalamus was found. As revealed spectrofluorimetrically unchanged pyrroxan molecules disappeared from the plasma and the organs within 2 hours. When pyrroxan-14C was used the radioactivity in the organs was demonstrated for 24 hours, and in the plasma for several days; this indicated the formation of pyrroxan metabolites or its complexes with the plasma proteins and structural elements of the organs. The selective accumulation of pyrroxan in the hypothalamus can account for the high efficacy of this drug in different hypothalamic disorders coursing with the overexcitation of the sympathetic nervous system.

Animals↗