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V Mares

Publications and source records attributed to V Mares.

At least 91 records · Page 5Linked to original sources
PubMed1982

The synthesis and transport of fucosylated glycans in the immature mouse cerebellum. An autoradiographic and microchemical study of differentiating cell and tissue compartments.

A study of 3H-fucose incorporation in the immature mouse parenchyma revealed that the rate of synthesis of fucosylated glycans in the neuropil of more differentiated internal granular layer, as well as in the PURKINJE cell bodies is higher than in the less mature external granular layer. The 3H-fucose incorporation into the choroid plexus, meninges, and blood vessel walls exceeds highly incorporation into the cerebellar parenchyma. A follow-up autoradiographic study revealed remarkable differences in the radioactivity of incorporated 3H-fucose in the "cell-body rich" and "cell-fibre rich" layers indicating transport of newly synthesized glycans from the perikarya of differentiating cells into their processes extending mainly into the molecular layer and the cerebellar medulla. It is assumed that the increased rate of 3H-fucose incorporation reflect 1. increasing complexity of the fucosylated glycans of differentiating cells 2. increase in the turnover of cell membrane components, 3. accelerated export of glycosylated compounds into the outgrowing fibres of differentiating cerebellar cells.

Animals↗
PubMed1982

Alpha-fetoprotein in the brain of developing rats and pigs. An immunofluorescent study of cell-and-tissue differentiation.

Alpha-fetoprotein (AFP) and some other serum proteins have been studied in the developing brain of rats and pigs using the indirect immunofluorescence technique. AFP is shown to be present in the ventricular ependyma, meningeal envelopes, the choroid plexus, blood vessel walls and in a wide scale of differentiating parenchymal cells ever since early embryonic ages of both species. In brain parenchyma the content of AFP is low in immature germinative cells; in both species it starts increasing in postmigratory neuroblasts and reaches a peak at the time of accelerated nerve cell differentiation. In rats, the amount of AFP is highest towards the end of the first postnatal week; then it starts decreasing and disappears towards the end of the 3rd week. In both species AFP is localized in the cytoplasm of nerve cell perikarya and their differentiating processes. Higher concentration of this protein has often been observed at the axonal pole of the cytoplasm of differentiating pyramidal neurons. Immunoglobulin G has been found in non-parenchymal structures, and small amounts also in parenchymal cells of embryonic and early postnatal rats following a pattern of cell-and-tissue distribution similar to that of AFP. In pigs, a low amount of albumin has been shown in differentiating leptomeninges. These data suggest uptake of AFP, and some other serum proteins, from the cerebrospinal fluid into cells of the immature rat and pig brain and its increase (or higher binding) in differentiating neurons.

Animals↗
PubMed1980

Cytophotometric re-investigation of DNA content in Purkinje cells of the rat cerebellum.

Stage scanning cytophotometry of Feulgen-stained cell nuclei of the cerebellum of young adult rats revealed that the absorbance values of the majority of the Purkinje cells show a Gaussian distribution with a low coefficient of variance. The peak absorbance of this population is the same as that of the granule cells. About 1% of the Purkinje cells measured, were found to have a stain content which indicates a 4C amount of DNA. For both the granular and the Purkinje cell population, a very small number of nuclei possesses absorbance values intermediate between 2C and 4C. The present data suggest prevalent diploidy of the Purkinje cells, and are at variance with those postulating a 'tetraploid and/or hyperdiploid' status of this population.

Animals↗
PubMed1979

Constancy and variability in the content of DNA in cerebellar Purkinje cell nuclei. A cytophotometric study.

A cytophotometric study of DNA content in Purkinje cells of the cerebellum of rats, cats, chicken and humans (Feulgen staining) revealed that in a certain number of cells the amount of NDA ranged between the diploid and tetraploid level (H2C cells). The incidence of H2C Purkinje cells varied among the species studied. In rats, which were studied most thoroughly, these cells amounted on average to 3%. In some rats, as well as in some cats and chickens H2C Purkinje cells were entirely absent. In the group of animals possesing H2C Purkinje cells, great interindividual differences were observed. In rats for instance, the incidence of these cells varied from 1 to 23 per cent. Topographic analyses carried out in rat and human cerebellum revealed that H2C Purkinje cells occurred more frequently in the hemispheres than in the vermis. No significant differences were found in the number of H2C Purkinje cells in healthy and Kilham-DNA-virus infected rats. Densitometric analysis of the distribution of nuclear chromatin showed that H2C Purkinje cells were richer in condensed chromatin, especially in the region of the nucleolus, which apparently contains the hyperploid surplus of DNA. It is proposed that the phenomenon of DNA hyperdiploidy arises as a result of either incomplete S-phase in some immature Purkinje cell precursors or the amplification of some DNA sequences particularly those localized in the nucleolar region.

Aged↗
PubMed1978

Nuclear pore complexes in cells of the developing mouse cerebral cortex.

The nuclear pore complexes of cells of the superficial layers of the cerebral cortex of mice were studied by freeze-etch technique. The nuclear membrane was found to be randomly penetrated by typical octagonal pore complexes in all age groups studied. The density of pores (per micron2) amounted to 7.8, 14.0, 17.0, 18.1 and 14.1 on the 18th to 20th embryonic and the 8th, 15th, 50th and 180th postnatal day respectively. The total number of pores per nucleus increases 5.2 times from the 18th to 20th prenatal to the 15th postnatal day and then decreases toward the 180th postnatal day (1257, 6582 and 3385 pores per nucleus respectively). The density of pores in cells of brain cortex, found in young adult mice is relatively high, if compared with other cell types.

Animals↗
PubMed1978

Nuclear pole complexes in cells of developing mouse cerebral cortex.

The nuclear pore complexes of cells of the superficial layers of the cerebral cortex of mice were studied by freezeetch technique from the 18--20th embryonic to 180th postnatal day. The nuclear membrane was found to be randomly penetrated by pore complexes in all age groups studied. The pores have a typical octagonal shape. The density of pores (per/um2) amounted to 7.8, 14.0, 17.0, 18.1 and 14.1 on 18--20th embryonic and 8th, 15th, 50th and 180th postnatal day respectively. The total number of pores per nucleus amounted to 1257, 6582, 5405 and 3384 on the 18--20th embryonic and the 15th, 50th and 180th postnatal day respectively. Thus the total number of pores per nucleus increases 5.2 times from the 18th--20th prenatal to the 15th postnatal day and than slightly decreases toward the 180th postnatal day. The density of pore complexes in adult brain cell nuclei is therefore very high in comparison with other normal somatic and cancer cells.

Age Factors↗
PubMed1977

DNA synthesis in the ventricular myocardium of young rats exposed to intermittent high altitude (IHA) hypoxia. An autoradiographic study.

Intermittent high altitude (IHA) hypoxia (7000 m) increased the wet weight of the right ventricular myocardium of 30-day-old rats after two 4 h/day exposures. During the same period the number of DNA-synthesizing nuclei of both muscle and non-muscle cell types increased proportionally. After 4 such exposures to hypoxia the number of 3H-thymidine-labelled nuclei in both cell types increased further. In addition, the number of labelled nuclei increased significantly in the yet un-enlarged left ventricle. While there was no difference in the number of DNA-synthesizing cells between the right and left ventricles in control animals, a significant increase in the number of cells involved in DNA synthesis in the right ventricle was found in both groups of animals exposed to IHA hypoxia. These results show that DNA synthesis in myonuclei of the ventricular myocardium can be stimulated in 30-day-old rats, i.e. at the very end of the weaning period.

Altitude↗
PubMed1977

Postnatal changes in the DNA content of mouse cerebral hemispheres.

Changes in the wet weight of the cerebral hemispheres and in their DNA content and concentration were studied in CBA mice (non-SPF, Velaz, Prague) aged from 1 to 270 days. It was found that hemisphere wet weight rose by 350% between the 1st and 14th day and by a further 11% between the 14th and 180th day. In the next three months it remained stable. The total DNA content rose by 30% between the 1st and 2nd day and by 45% between the 1st and 10th day; changes between the 10th and 180th day were non-significant, but a decrease of 16% occurred by the 270th day. Between the 1st and 2nd day the DNA concentration did not alter, or rose non-significantly (+20%). Towards the end of the 2nd postnatal week it fell exponentially (-75%). Changes in the DNA content and concentration indicate that the rate of cell proliferation in mouse cerebral hemispheres is highest on the first two days after birth, while the general chemical composition of the hemisphere develops fastest between the 2nd and 14th day. The constancy of the DNA content between the 10th and 180th day implies that cell division in the hemispheres of adolescent and adult mice primarily reflects renewal of the non-neuronal cell population.

Animals↗
PubMed1976

Neurogenesis in the visual system of the rat. An autoradiographic investigation.

Rats of the BD III strain were injected with a single dose of 3H-thymidine on either the twelfth, fourteenth, sixteenth, eighteenth or twentieth day of gestation (ED 12. . . . .ED 20) or on the postnatal day one, three, or seven. Animals were killed at age 22 to 24 days. DNA synthesis, as an indicator of cell division, was studied in matrix precursors of nerve and glial cells in the visula centers, including the lateral geniculate body (LGB), the superior colliculus (SC) and the visual cortex (VC). It was found that proliferation of matrix precursors of nerve cells destined for all the regions studied was in progress on ED 12. In the subcortical regions (LGB, SC) this process was substantially more advanced than in the VC. The first neuroblasts appeared in the SC (ED 12) and only later (ED 14) in the LGB and VC. In comparison with the LGB, VC neuroblasts were quite rare on ED 14 and were present only in layer VI. They appeared more frequently in this region only after injection of isotope on ED 16. Matrix cell proliferation and nerve cell formation ceased in the LGB between ED 16 and ED 18. The number of labeled cells arising after injection of the isotope on ED 16 indicates that neurogenesis ceased somewhat earlier in the dorsal nucleus of the LGB than in the ventral. In the SC the last neurons arose between ED 18 and ED 20, and in the VC, with the possible exception of a few granular neurons (which may continue division into the first few days postnatally), proliferation continued until the end of gestation. The origin of neuroblasts initially followed a caudo-rostral gradient. Later, the times of neurogenesis in the regions studied overlapped significantly. This is clear, for example. on ED 16, when neurogenesis in the mesencephalic SC continued for about two days longer than in the more postral LGB, and coincided with that in the VC, especially in the deep layers. The end of neurogenesis in the LGB, especially in the ventral nucleus, coincided with the time of neurogenesis in the deep cortical layers. In the VC, and partly also in the SC, an inside-out pattern of proliferation and neuron formation was confirmed. The times of proliferation of precursor cells, with the exception of the very end of neurogenesis, substantially overlapped within both these regions. The degree of this overlapping, described in terms of Labeling Index values, decreased towards the end of the neurogenetic period. Division of neuroglial cell precursors, started as early as on ED 14 in/for subcortical centers (LGB, SC), but not until ED 18 in/for the VC. A few labeled endothelial-like cells were observed in all regions studied after isotope injection on ED 12.

Age Factors↗