PubMed Health⌕ Search

Biomedical subjects

T V Pavlova

Publications and source records attributed to T V Pavlova.

At least 19 recordsLinked to original sources
PubMed2006

Pentylenetetrazol kindling in rats: Is neurodegeneration associated with manifestations of convulsive activity?

Structural changes in neurons and measures of oxidative stress were studied in the hippocampus of rats tolerant (ST) and sensitive (SS) to developing clonic-tonic seizures in conditions of pentylenetetrazol kindling. Sequences of 11 injections of pentylenetetrazol significantly decreased the number of normal neurons in hippocampal field CA1 in SS rats, this effect being seen in both hippocampal field CA1 and the dentate fascia in ST rats. Decreases in the numbers of normal neurons were accompanied by increases in the numbers of damaged cells in field CA4 in rats of both groups. After 21 injections, decreases in the numbers of normal neurons were seen in field CA1 in both SS and ST rats, while the numbers of damaged neurons were significantly greater than control only in ST rats in fields CA1 and CA4. The glutathione level was significantly lower in the hippocampus in both groups of rats than in controls. Thus, rats " tolerant" to developing convulsions show signs of oxidative stress and neurodegenerative changes in the hippocampus. This suggests that oxidative neuron damage leading to neurodegeneration in the pentylenetetrazol kindling model is not directly associated with convulsive activity.

Animals↗
PubMed2005

[Pentylenetetrazole kindling in rats: whether neurodegeneration is associated with manifestations of seizure activity?].

Structural changes in neurons and oxidative stress in hippocampus were studied in rats "tolerant" (TR) and susceptible (SR) to tonic and clonic seizures in pentylenetetrazole (PTZ) kindling. The number of normal neurons was significantly decreased in CA1 subfield of TR hippocampus after 11 injections of PTZ, while in SR neuronal cell loss was evident in CA1 and fascia dentata. In both groups, neuronal cell loss was accompanied by increase in damaged neuron number in CA4 subfield. After 21 injections of PTZ, the decrease in normal neuron number was revealed in CA1 subfield of both TR and SR, while the number of damaged neurons was above the control level in hippocampal subfields CA1 and CA4 in TR only. Glutathione level was decreased in hippocampus of both TR and SR as compared with control rats. Thus, rats tolerant to PTZ-induced convulsions demonstrated oxidative stress and neurodegeneration in hippocampus. The results suggest that, in PTZ kindling model, oxidative damage of neurons resulting in neurodegeneration in hippocampus is not directly related to the convulsive activity.

Animals↗
PubMed2003

[Effectiveness of lamivudine in the treatment of chronic HBeAg-negative viral hepatitis B: results of continuous therapy for 18 months].

The efficacy of monotherapy with one of the analogues of synthetic nucleosides (lamivudine) was studied in 22 patients with chronic viral hepatitis B (CVHB). The specific feature of the selected group was that there was no serum HBeAg, which is usually regarded as a sign of viral mutation. The time course of changes in the activity of blood and hepatic inflammatory processes and viral replication were studied at equal intervals. There was a direct correlation between the suppression of viral replication and the regression of activity indices, such as ALT, serological markers, DNA of viral hepatitis B, and the morphological constituents of the Knodell index) during lamivudine therapy. However, there were no substantial changes in the parameters of fibrosis throughout the treatment. Therapy resistance was revealed in 3 of the 22 patients with CVHV. Its basis was the mutation of hepatitis B virus in the YMDD-motive, which was detected in 2 of the 3 patients.

Adult↗
PubMed1999

Dehydrogenase activity of infected cells and biological properties of HIV-1 variants.

Changes in dehydrogenase activity of some continuous cell lines were studied during the response to acute infection in vitro with HIV-1 variants having different biological features. Soon after infection, the dehydrogenase activity of infected cells increased, and this increase was greater and more prolonged with the HIV-1 r/h variant than with the HIV-1 s/l variant. Later stages showed decreased dehydrogenase activity of HIV-1-infected cells compared to the noninfected control; this is a manifestation of the cytodestructive effect of the virus. The changes increased monotonously (but not in direct proportion) with an increase in the infecting dose.

Cell Line↗
PubMed1992

[The architectonics and ultrastructure of the chorionic vessels of the human placenta].

By means of injection, corrosive, histological methods, light microscopy with elements of morphometry, electron (transmissive and raster) microscopy, 260 preparations of the human placenta have been studied. The notion on the order of villi branching, on intraorganic architectonics has been expanded, intrarelations of the vessels with the villous stroma have been verified, the notion on the syncytiocapillary barrier has been widened. The terminal type of the arterial branching in the chorion has been determined up to 8-9 orders, as well as appearance of vascular continuity, that is arteriolo-arterial, veno-venular and arteriolo-venular anastomoses, mainly at the level of intermediate and terminal villi. Large vascular anastomoses are found in the placental areas with massive depositions of fibrinoid.

Arteries↗
PubMed1991

[Effect of a single overheating on kidney ultrastructure].

Large human populations have to live and work under conditions of heat in the arid zones or in industry. It is shown in the experiment, that a single overheating of animals of various duration results in a considerable damage of glomeruli and tubules the clinical manifestation of which is the development of acute renal failure.

Acute Kidney Injury↗
PubMed1986

[Ultrastructural changes in the capillaries of the placenta during hypoxia].

To investigate early stages of hypoxia, the authors studied fetal capillaries of the terminal cilia in the placenta of women without clinical manifestations of fetal hypoxia in such pathologic states as protracted labor, uterine fibromyoma, late toxicosis of pregnancy. The capillaries are shown to have the same typical changes: the increase of nuclear volume, of the number of cytoplasmic organellae (mitochondria, cysternae of the granular endoplasmic reticula, polysomes and free ribosomes, pinocytic vesicules) and cytoplasmic appendages, which come into active contact with the blood cells. These changes are directed to normalization of oxygen and nutrient supply to the fetus.

Capillaries↗
PubMed1985

[Ultrastructural and ultracytochemical characteristics of the terminal villi of the placenta in EPH-toxemia of pregnancy].

The main types of the terminal villi in the EPH-toxicosis of pregnancy with various degrees of severity are studied with light, scanning and transmission electron microscopy and ultracytochemistry. The incipient stages of the transition from normal to pathologically changed villi could be detected by means of ultrastructural study only. Enhancement of the degenerative processes in placenta occurs as the severity of this complication increases.

5'-Nucleotidase↗
PubMedDate not supplied

[New approaches to the chemotherapy of HIV infection].

The preclinical analysis of the effectiveness of AZT and new compounds (sulphatized derivate of chitosan (Sch) and adamantileted Sch, contents 10 and 18% of adamantine) prepared on the basis of chitosan (Ch), carried out with the use of the experimental clinical test system (the in vitro model of peripheral blood mononuclears of a concrete patient) developed in laboratory, is presented. Both combinations in concentration 0.01 mkg/ml are decreased HIV antigens till 6.4 and 8.6% accordingly, while whilst initial Sch hare caused less effect in 4-5 fold.

Anti-HIV Agents↗
PubMedDate not supplied

[Pentylenetetrazole kindling induces caspase-3 activation in rat brain].

Pentylenetetrazole kindling (but not a single pentylenetetrazole injection) induced caspase-3 activation in the cerebral cortex, hippocampus, and cerebellum of rats as well as neurodegeneration in the hippocampus. The number of neurons in the CA3 subfield of the hippocampus decreased significantly, whereas no apoptotic nuclei could be detected. The results support a possible non-apoptotic involvement of caspase-3 in brain plasticity.

Animals↗
PubMedDate not supplied

[Effects of morphine withdrawal on the indices of free radical homeostasis and nitric oxide system in rat liver and thymus].

Indices of oxidative stress, nitric oxide (NO) metabolism as well as the activity of caspase-3, an important enzyme of apoptotic cell death, were measured during the morphine withdrawal syndrome in liver and thymus of rats. Male Wistar rats were administered with morphine hydrochloride (i.p., at increasing doses from 10 to 100 mg/kg, twice a day, for 6 days). Thirty-six hours after the last administration the withdrawal syndrome was monitored using the specific autonomic and locomotor indices. During this period, weights of body and thymus significantly decreased. Oxidative stress in liver was accompanied by an increase in aspartate aminotransferase and gamma-glutamyl transferase in blood serum. No signs of oxidative stress could be demonstrated in thymus. The activity of the Ca(2+)-dependent isoform of nitric oxide synthase (NOS) in liver increased, while, the activity of the Ca(2+)-independent NOS diminished, the total activity of NOS in liver and thymus remained unchanged. The concentration of nitrates/nitrites in blood was decreased, in thymus increased, and in liver unchanged. Caspase-3 activity changed neither in liver, nor in thymus. The results are discussed from the perspective of possible antioxidant and antiapoptotic role of NO during morphine withdrawal syndrome.

Animals↗
PubMedDate not supplied

[Irrigation therapy as a method of intensive care of ophthalmopathology in the posterior eye segment in children].

Presented in the paper are data of a comparative analysis of efficiency of different methods of administration of drugs in neuritis and partial atrophy of the optic nerve. New techniques of application and fixation of irrigation systems in the retrobulbar and Tenon's space are described. Experimental and clinical data proving advantages of the new method of administration of drugs by an automatic pulse doser in the treatment of inflammatory diseases of the optic nerve are represented. The use of such intensive intermittent technique of administration of drugs in Tenon's space performed at the preliminary stage before electrostimulation of the optic nerve made the procedure by far more effective and ensured better treatment results.

Animals↗
PubMedDate not supplied

[Impact of maternal thyroid disease on the formation of relationships in the maternal-placental-fetal system].

Impaired microcirculation with evolving sludge phenomenon and thrombosis underlie placental changes in maternal thyroid disease. Capillary blood circulatory defect is largely due to villous immaturity. Placental tissue ischemia gives rise to fibrinoid, sclerosis, and alternative processes. Dysadaptive changes are mostly observed in thyrotoxicosis and hypothyroidism. Adaptive processes evolving at the ultrastructural level are best pronounced in euthyroid goiter.

Adult↗