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Biomedical subjects

O V Smirnova

Publications and source records attributed to O V Smirnova.

At least 37 records · Page 2Linked to original sources
PubMed1998

[Use of transesophageal left atrial cardiac pacing for assessment of cordarone effectiveness in patients with atrioventricular tachycardia].

AIM: To assess by means of transesophageal left atrial pacing the effectiveness of cordarone treatment for arrhythmias caused by re-entry mechanism. MATERIALS AND METHODS: Effectiveness of cordarone treatment was estimated in 25 patients with atrioventricular nodal tachycardia (AVNT) and in 33 patients with WPW syndrome and reciprocal atrioventricular tachycardia (RAVT) with frequent paroxysms of tachycardia 1-5 times per week. Transesophageal left atrial pacing (TELAP) was performed before antiarrhythmic treatment and on cordarone treatment day 14-18. Cordarone was given for two months in common regimen (the first 10 days--600 mg/day, the next 10 days--400 mg/day and then 200 mg/day). RESULTS: The first TELAP induced paroxysmal AVNT or RAVT in all the patients. According to the results of the second TELAP, all the patients were divided into three groups. Group 1 included 28 patients in whom the second TELAP was unable to induce tachycardia. All these patients had increased effective refractory period (ERP) of AV node and/or of accessory pathway (AP) values and a decreased Wenkebach point (WP) < 150/min during the second TELAP in comparison with the first TELAP. All these patients had no spontaneous paroxysms of T during the 3-month follow-up. Group 2 included 18 patients in whom the second TELAP induced AVT lasting < 30 seconds. 16 of these patients had tachycardia with less heart rate during the second TELAP in comparison with the first TELAP, 153 + (-) 8 bpm vs 188 + (-) 10 bpm, p < 0.001, respectively. Also, in these 16 patients we found an increase of values of ERP of AV node and/or AP > 360 ms and a decrease of WP < 150 bmp. 14 of these 16 patients had no spontaneous paroxysms of AVT and 2 patients had short episodes of AVT during the 3-month follow-up with effects of vagal manoeuvers. From 2 other patients of group 2 one had short episodes of spontaneous T and one had long episodes of tachycardia with effect of verapamil i.v. Group 3 included 12 patients in whom the second TELAP induced the same AVT as the first TELAP. Values of ERP of AV node and/or AP and WP during the first and second TELAP were not different. All of these patients had long spontaneous paroxysms of AVT during cordarone treatment day 14-18. The treatment was discontinued in all patients of group 3. CONCLUSION: Cordarone is effective in prevention of AVT. Negative results in provocation of AVT during TELAP after 14-18 days of cordarone treatment is a very specific predictor of cordarone treatment effectiveness. Provocation by TELAP of short episodes of AVT with reduced heart rate and higher values of ERP of AV node and AP and lowering of WP < 150 bpm may not predict ineffectiveness of cordarone in patients with AVT. Moreover, the majority of these patients had no spontaneous episodes of AVT. Provocation by TELAP during cordarone treatment of the same AVT episodes as before cordarone treatment is a very specific predictor of cordarone effectiveness.

Adult↗
PubMed1998

[Myelopeptides: isolation and structure].

A new method was developed for the isolation of biologically active peptides present in small quantities in supernatants of bone marrow cell cultures. Four new peptides, which exhibited immunostimulating and differentiating activities, were isolated from the supernatant using solid phase extraction and reversed-phase HPLC. For these peptides, the following primary structures were elucidated: Leu-Val-Cys-Tyr-Pro-Gln, Phe-Arg-Pro-Arg-Ile-Met-Thr-Pro, Val-Val-Tyr-Pro-Asp, and Val-Asp-Pro-Pro.

Adjuvants, Immunologic↗
PubMed1998

[Combined use of left atrial transesophageal pacing and cordarone in atrial flutter].

AIM: To investigate the effectiveness of superfrequent transesophageal left atrial stimulation (TLAS) and its combination with cordarone in management of atrial flutter (AF). MATERIALS AND METHODS: 650 patients with paroxysmal AF underwent TLAS. The paroxysm duration varied from 1 hour to 1 month. In 312 patients TLAS was performed prior to treatment with antiarrhythmic drugs (group 1), in 338 patients--after intravenous administration of cordarone (group 2). RESULTS: Superfrequent TLAS has restored sinus rhythm (SR) in 85(27.2%) and 169(50%) patients of groups 1 and 2, respectively (p < 0.001). TLAS promoted conversion of AF in atrial fibrillation (AFi) in 185(59.3%) and 159(47.1%) patients of groups 1 and 2, respectively (p < 0.01). Moreover, SR recovered 24-48 hours after TLAS in 87(27.9%) and 64(18.9%) patients of groups 1 and 2 respectively (p < 0.01). Sinus rhythm recovered in a total of 172(55.1%) and 233(69.0%) patients, AF was converted to AFi in a total of 88(31.4%) and 95(28.1%) patients (p > 0.05) of groups 1 and 2, respectively. TLAS was uneffective in 42(13.5%) and 10(2.9%) patients of groups 1 and 2, respectively. CONCLUSION: Superfrequent TLAS is a highly effective and non-invasive modality in the treatment of paroxysmal AF. It promotes recovery of SR. In some patients TLAS induces AFi which is more controllable by medication as regards the heart rate. Cordarone contributes to the response to TLAS in patients with paroxysmal AF.

Amiodarone↗
PubMed1995

[New polymorphic variants of the gene for human blood coagulation factor IX].

The polymorphism of Alu-repeats, which are located in the introns of the human factor IX gene (copies 1-3), was studied. To identify polymorphic variants, direct sequencing of PCR products that contained appropriate repeats was used. In each case, 20 unrelated X chromosomes were studied. A polymorphic Dra I site was found near the 3'-end of Alu copy 3 within the region of the polyA tract. A PCR-based testing system with internal control of restriction hydrolysis was suggested. Testing 81 unrelated X chromosomes revealed that the frequency of the polymorphic Dra I site is 0.23. Taq I polymorphism, which was revealed in Alu copy 4 of factor IX gene in our previous work, was found to be closely linked to Dra I polymorphism. Studies in linkage between different types of polymorphisms of the factor IX gene revealed the presence of a rare polymorphism in intron A that was located within the same minisatellite region as the known polymorphic insertion 50bp/Dde I. However, the size of the insertion in our case was 26 bp. Only one polymorphic variant was found among over 150 unrelated X chromosomes derived from humans from Moscow and its vicinity.

Base Sequence↗
PubMed1995

[Polymorphism at codon 117 of the granulocyte-macrophage colony-stimulating factor (GM-CSF) gene].

A T-to-C substitution, replacing a hydrophobic isoleucine residue with a hydrophilic threonine residue in position 100 of a mature protein molecule, was found at codon 117 of the GM-CSF gene. The mutation frequencies were estimated in 51 DNA samples from healthy adult donors and also in 20 samples from patients with different neoplastic myeloid disorders. Almost equal substitution frequencies in patients and normal individuals were observed, suggesting that the defect was not associated with leukemia. Additionally the GM-CSF gene intron 1 sequence was refined.

Adult↗
PubMed1994

Immunocytochemical localization of prolactin receptors in rat liver cells: I. Dependence on sex and sex steroids.

The peculiarities of cellular and tissue distribution of prolactin receptors (PRLR) in the liver of female and male rats with different sex steroid status were investigated in paraplast-embedded tissue with the indirect immunoperoxidase technique. Two clones of antibodies directed outside the PRL-binding site (U6) or to the PRL-binding site (T6) of the receptor were used. PRLR-specific immunoreactivity was identified essentially in hepatocytes. PRLR can be visualized in sinusoidal domains of cellular membranes, in cytoplasmic granules and sometimes in the perinuclear area of hepatocytes. The staining characteristics were similar with both antibodies. There were no prominent differences in the intensity of PRLR-positive staining among hepatocytes of different zones of hepatic lobules with the exception of some hepatocytes around central veins. Sex differences in the intensity of immunostaining (strong in females, and faint in males) but not in the amount and distribution of PRLR-containing cells were observed. Gonadectomy of animals caused the disappearance of sex differences in the intensity of PRLR-positive staining as a result of its decrease in females and increase in males. The essential elevation in the intensity of PRLR-specific immunoreactivity was revealed in hepatocytes of gonadectomized females and males after prolonged estradiol administration (10 micrograms for 14 days). The cytoplasmic staining of some hepatocytes surrounding central veins was much more pronounced in estrogenized animals. PRLR-specific immunoreactivity in the perinuclear area was identified in these cells. Androgen treatment (3 mg of testosterone-propionate for 3 days) of gonadectomized animals caused a decrease in the intensity of hepatocyte PRLR-positive staining similarly in both sexes.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

[A new polymorphism in the human factor IX gene, useful for determining carriers of hemophilia B].

A new Taq I polymorphism in Alu repeat 4 of the human factor IX gene is reported. This polymorphism is associated with a C-T transition at the 72-bp position of the Alu repeat consensus sequence. A simple PCR system for testing of this structural anomaly, with internal control of restriction hydrolysis, was developed. The frequency of the new polymorphic site and its linkage with other polymorphisms of the factor IX gene were also evaluated. The new polymorphism was used for establishing hemophilia B carriers.

Base Sequence↗
PubMed1994

[Assessment of the frequency of finding polymorphic alleles of the human X-chromosome locus DXS52 in the Muscovite population].

The frequency of different polymorphic variants of the multiallelic locus DXS52 (St14) of the human X-chromosome, adjacent to the factor VIII gene, was evaluated by means of PCR for the heterogeneous population of Moscow and Moscow oblast'. It was shown that the heterozygosity index of this polymorphism in the studied population is much lower (0.71) than in Western Europe (0.80-0.85), which can apparently be explained by a higher frequency of the prevailing allele 1690 (0.52 compared to 0.36). Five new St14 alleles were detected during this study. The total informativity of the polymorphic markers St14 and HindIII (intron 19 of the factor VIII gene), which are most commonly used for hemophilia A detection, was evaluated. Among 83 investigated women, only 57 (69%) were heterozygous for at least one of the markers used, which is also much lower than in Western-European populations (90-95%).

Alleles↗
PubMed1993

Inheritance of androgen program of male-specific expression of unusual estrogen-binding protein by daughter hepatocytes at rat liver regeneration.

A possibility of inheritance of androgen and basic genetic programs at the level of unusual estrogen-binding protein (UEBP) by daughter hepatocytes was investigated. Liver regeneration after partial (2/3) hepatectomy or after selective poisoning of hepatocytes of the central zone of hepatic lobules with CCl4 in adult rats were used as models of total and zonal proliferation of hepatocytes, respectively. UEBP content and the pattern of its tissue expression in the course of liver regeneration were monitored by radioligand and immunocytochemical technique. In animals of all groups possessing the androgen program of UEBP expression (intact, castrated and/or hypophysectomized males, and ovariectomized females treated with androgen) UEBP content was shown to be similarly high before initiation and after completion of liver regeneration. Unlike in males, in androgenized females a transient 4-fold increase of UEBP concentration on day 4 after partial hepatectomy was observed. In animals with a basic genetic program at the level of this protein (ovariectomized females, neonatally castrated males) only trace amounts of UEBP were observed in intact as well as in regenerated liver. The data were confirmed by immunocytochemical technique. A gradient mode of distribution of UEBP-contained cells within hepatic lobules with the highest specific staining around central veins was found by immunocytochemical technique in males. Specific staining of centrolobular and periportal hepatocytes was 7- to 10-fold in intact, and 4- to 6-fold in castrated and/or hypophysectomized males. In intact females specific staining was distributed uniformly at extremely low levels similar to that in periportal hepatocytes of males. Androgen administration to ovariectomized females stimulated a significant and stable increase of UEBP content in two layers of hepatocytes surrounding the central vein. Profiles of specific staining of hepatocytes within the hepatic lobules similar to that in control animals were observed after the completion of liver regeneration of different groups of rats. The results obtained suggest all the hepatocytes to be targets for androgen programming, natural in males or experimental in females, while the extent of expression of this program depends on the position of a hepatocyte within the liver lobules and the sex of the animal.

Androgens↗
PubMed1992

Evidence for direct action of testosterone on rat liver cells: in vivo and in vitro induction of unusual estrogen-binding protein.

We demonstrate that on the rat liver, testosterone (T) induced differentiated functions and enhanced unusual estrogen-binding protein (UEBP) content through mechanisms dependent on cell activation by androgens, the presence of growth hormone (GH) and the hormonal status of the animal. To determine whether liver cells are a target for androgens, we measured T effects on UEBP in gonadectomized adult male and female rats in vivo and in vitro. In ovariectomized rats, T increased 8- to 9-fold UEBP levels that remained constant during 10 days. Also in vitro, using hepatocytes from ovariectomized rats, T alone increased UEBP levels 3-fold in a dose-response pattern. Combining a fixed low dose of GH with different concentrations of T increased UEBP 2-fold above T alone. Whereas GH alone had no effects in ovariectomized rats, hepatocytes were responsive to GH, in a dose dependent pattern that was abolished when T was used together with GH. On the other hand, T alone had no effect in hypophysectomized-ovariectomized animals. The latter group was rendered T responsive after the simultaneous injection of GH with T that increased UEBP content 6.6-fold in vivo. Castrated males revealed a marked responsiveness to T and GH in vivo and in vitro, when added separately or in combination. The results obtained suggest a complex regulatory system and we conclude that T acts directly on rat liver as: (1) an inducer of sex differentiation; and (2) a regulator of UEBP production in males. In addition, liver regeneration studies in castrated-hypophysectomized males revealed the UEBP phenotype in daughter cells in the absence of treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗