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Biomedical subjects

V Mares

Publications and source records attributed to V Mares.

126 records · Page 7Linked to original sources
PubMedDate not supplied

The action of cisplatinum (cis-DDP) on the postnatal growth of the rat liver. Cytokinetics and ultrastructural studies.

The early and late effects of cis-DDP treatment on liver cell kinetics were analyzed after its intraperitoneal injection into 17-day old rats. Frequency of binucleate hepatocytes, cellular DNA content distribution, 3H-thymidine labelling and ultrastructure of the nuclei were analyzed. Two days after treatment, a block of mononucleate hepatocytes in the S phase and in the G2 phase was demonstrated by the increase of intermediate 2c-4c and 4c DNA values in the absence of changes in 3H-thymidine labelling; 8c binucleate cells, which are essential for the formation of tetraploid mononucleate cells, were not found. In cell nuclei, large areas of more condensed chromatin appeared, perhaps providing further evidence for a G2 block. Seven days after treatment, there was a tendency to catch up with the normal situation, as shown by the unblocking of the S phase in mononucleate cells indicated by both cytophotometry and autoradiography. The presence of 8c binucleate cells and 4c-8c mononucleate cells indicates that 4c mononucleate hepatocytes are either diploid cells in the G2 phase or true tetraploid G1 cells. The decrease in the heterochromatin areas and the appearance of hypertrophic nucleoli demonstrate an increase in the metabolic activity of the nuclei. Thirty six days after treatment, the incidence of different DNA hepatocyte classes and the 3H-thymidine labelling were already similar in control and in treated rats.

Aging↗
PubMedDate not supplied

[The effect of methylazoxymethanol on neuronal differentiation in the murine cerebellum].

The effect of methylazoxymethanol (MAM), an antimitotic drug, on granule and Purkinje cells of the rat cerebellum was studied. MAM was injected subcutaneously into ICR mice on day 5 after birth. The number of nucleoli and DNA content in nuclei of cerebellar neurons were determined 2 and 12 days after the injection. The number of nucleoli served as a criterion of maturity of neurons. On day 2 after MAM administration the proportion of Purkinje cells containing a smaller number of nucleoli increased suggesting a direct effect of MAM on maturation of Purkinje neurons. On day 12 no difference in the number of nucleoli was found between experimental and control animals but the number of granule cells containing multiple nucleoli increased significantly. The latter suggests that the studied cell population was supplemented with less mature cells. As a result, development of Purkinje and granule cells is desynchronized and that appears to determine the secondary effect of MAM on Purkinje cell differentiation.

Aging↗
PubMedDate not supplied

[Shifts in the constant potential in the structures of the rat brain in focal ischemia and systemic hypoxia].

The role of spreading depression (SD) in the development of ischemic brain damage in rats was studied in two models: focal cortical ischemia provoked by a photothrombotic occlusion of the middle cerebral artery (MCA) and systemic hypoxia induced by breathing with 0.8% carbon monoxide (CO). Spontaneous cortical SD waves occurring during illumination were found to delay the irreversible MCA occlusion. Thrombosis was probably prevented by episodes of striking vasodilation and hyperemia lasting for 1-2 min and accompanying every SD wave. The SD-induced hyperemia after permanent MCA occlusion seems to improve the oxygen supply of the penumbra zone. During hypoxia induced by one-hour respiration with 0.8% CO, COHb saturation of the blood reached 50-60%. SD waves occurred in different brain regions of lightly anesthetized rats (pentobarbital, 20 mg/kg) changed under the above conditions into prolonged depolarizations (HDs) which led to a substantial increase in animals' mortality (60%). The SDs evoked in the cortex and hippocampus of deeply anesthetized rats (pentobarbital, 50 mg/kg) showed that hippocampus became highly vulnerable by CO hypoxia. Duration of the SD-provoked HDs often reached 30-60 min after a single SD wave. Decreased cell density was found in CA1 area of the hippocampus 20-30 days after the CD-enhanced CO hypoxia. Cerebrolysin (2.5 ml/kg daily, during 10 days) prevented from severe hippocampal injury (formation of granulomas) usually seen in the left hemisphere of rats not treated with cerebrolysin.

Acute Disease↗