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Biomedical subjects

V Mares

Publications and source records attributed to V Mares.

At least 109 records · Page 6Linked to original sources
PubMed1976

An autoradiographic study of gliogenesis in the rat lateral geniculate nucleus (LGN).

Rats pregnant for 14, 16, 18 and 20 days, as well as 1-, 3-, 7-, 12-, 16- and 21-day-old offspring, received a single injection of [3H]thymidine and were killed at postnatal ages of 22-27 days. An autoradiographic study of DNA synthesis revealed that proliferation of non-neuronal matrix cell precursors destined for the dorsal part of the lateral geniculate nucleus had already started by gestational day 14. Quantiative evaluation of the incidence of labelled cells revealed 2 peaks occurring in both groups of non-neuronal cells at postnatal days (PD) 7 and 16. It has been assumed that the accelerated production of ectodermally derived glial cells, observed towards PD 7, relfects the enhanced growth of the neuronal surface covered with glial cell processes, and that at PD 16 formation of myelin sheaths. Changes in the number of labelled cells of mesodermal origin in the course of development can probably be attributed to the rate of vasculogenesis of the studied region.

Animals↗
PubMed1976

Fate of 3H-thymidine labelled myogenic cells in regeneration of muscle isografts.

Intact and denervated extensor digitorum longus (EDL) muscles of 20-day-old inbred Lewis-Wistar rats were labelled with 3H-thymidine. Ninety minutes after the injection of the isotope 4.0% of the nuclei were labelled in the intact (i.e. innervated) and 9.6% in the muscles, denervated 3 days before administration of the isotope. The labelled EDL muscles were grafted into the bed of the previously removed EDL muscles of inbred animals and these isografts were studied 30 days later. In the EDL muscles, regenerated from innervated isografts only occasionally labelled endothelial cells were found whereas in the muscles regenerated from denervated isografts also parenchymal muscle nuclei were regularly labelled. The incidence of labelled nuclei in the regenerated EDL muscles was, however, about 20 times lower than in the donor EDL muscles. The presen experiments provide a direct proof of utilization of donor satelite cell nuclei for regeneration in grafted muscle tissue. With respect to the low incidence of labelled nuclei in regenerated EDL muscles, other sources of cells apparently also contribute to the regeneration process.

Animals↗
PubMed1976

Experimental allergic encephalomyelitis.-- The effect of dexamethasone on growth and proliferation in the draining lymph node.

Dexamethasone, when administered from day 0 to day 9 following the sensitizing injection of encephalitogenic protein in complete Freund's adjuvant, suppressed both the characteristic enlargement of the paracortical area of the draining lymph node and the development of clinical and histopathological signs of experimental allergic encephalomyelitis. Division of cells within the node was not inhibited and therefore the effect of dexamethasone appeared to be a consequence of reduced migration of lymphocytes into the node.

Animals↗
PubMed1975

An estimate of the number of cells arising by division in mouse cerebral hemispheres from age one to 12 months: an autoradiographic study of DNA synthesis.

Male CBA strain mice aged 1, 2, 4, 6, 8 and 12 months were injected with 5 muCi of 6-H3-thymidine per gm body weight and killed two hours after the injection. Incorporation of the isotope, as a measure of DNA synthesis and cell division, was studied in the cerebral cortex and corpus callosum by light-microscope autoradiography. DNA synthesis was found in a small number of nuclei of non-neuronal cells, both of ecto- and mesodermal origin. The percentage of labeled cells (Labeling Index, or LI) decreased in both regions exponentially with age. On the base of measured LI values, the total number of cells arising from age one to 12 months was calculated. As the reference value the number of cells in one month-old animals was taken. The calculated cell increment in the ectodermal population in the cortex amounted to 19.7-20.6% (average 20.2%) and to 196.0-425.0% (average 247.0%) in the corpus callosum (pairs of figures correspond to values calcualted from LI values measured in sagittal and frontal sections). When all labeled cells (LC) were taken into consideration (of both ecto- and mesodermal origin) the corresponding cell increment ranged from 25.0-30.5% (average 26.8%) in the cortex and from 205.0-454.8% (average 263.0%) in the corpus callosum. The number of all newly arising cells in the whole hemisphere (including both cerebral cortex and corpus calosum) calculated from mean LI values of all LC in sagittal and frontal sections amounted to 52.0%. It is suggested that the observed DNA synthesis and cell division, particularly in the corpus callosum and mesodermal cell groups of both regions studied, correspond mainly to renewal of cell populations. In the cerebral cortex accumulation of some newly arising cells in situ cannot be excluded.

Aging↗
PubMed1975

An autoradiographic study of regional differences in DNA synthesis in the brains of young adult mice.

An autoradiographic study of DNA synthesis has shown that repeated injections of 3HTdR result in marked regional differences in labelling of non-neuronal cells in the brains of young adult mice. The incidence of labelled cells was highest in the rudimentary subependymal layer. In the white matter of the corpus callosum and hippocampal commissure, the incidence of LC was several times higher than in the grey matter. Substantial difference was found in the number of labelled cells in the granular population of the olfactory bulb and the dentate gyrus of the hippocampus on the one hand, and the cerebellum on the other. Higher LI values in regions closely associated to rudimentary subependymal layer provide indirect evidence of a selective migration of dividing subependymal cells into neighbouring "target" structures.

Animals↗
PubMed1974

Stability of DNA in Purkinje cell nuclei of the mouse. An autoradiographic study.

Neurons of the mouse were labeled with [(3)H]thymidine during their prenatal period of proliferation. The (3)H activity of the Purkinje cell nuclei was then studied autoradiographically 8, 25, 55, and 90 days after birth. The measured grain number per nucleus decreased by about 14% between the 8th and 25th postnatal days and then remained constant up to 90 days. There was no significant decrease of the (3)H activity of the Purkinje cell nuclei after correction of the measured grain number per nucleus for increasing nuclear volume of the growing Purkinje cells and for the influence of [(3)H]beta self-absorption in the material of the sections. Injection of a high dose of [(3)H]thymidine into young adult mice did not result in (3)H labeling of either Purkinje or other neurons in other brain regions. The results agree with the concept of metabolic stability of nuclear DNA. "Metabolic" DNA could not be observed in these experiments.

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