PubMed Health⌕ Search

Biomedical subjects

Z Lodin

Publications and source records attributed to Z Lodin.

At least 19 recordsLinked to original sources
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↗
PubMed1979

Regional distribution of membrane-bound gamma-glutamyl transpeptidase activity in mouse brain. Comparison with rabbit brain.

Activity of membrane-bound gamma-glutamyl transpeptidase (gamma-GTP) was examined in various regions of mouse brain, in capillaries of the cerebral cortex and in telencephalic choroid plexuses. The level of activity in the capillaries was double and that of the choroid plexus nine times that of the gamma-GTP activity found in the brain, septum, hippocampus, hypothalamus, thalamus, cerebellum, frontal cortex, pons, medulla oblongata, and amygdala. Histochemically the gamma-GTP activity was demonstrated in the surface membranes of choroidal cells and in the endothelium of small capillaries. The activities of gamma-GTP of cerebral cortex, choroid plexus, and capillaries from rabbit were 5--17 times greater than those from corresponding areas of mouse brain. While 30 mM methionine stimulated (in vitro) the enzyme from mouse brain, no such effect was observed with the enzyme activity from rabbit brain. The gamma-GTP activity from the capillaries of cerebral cortex of both mouse and rabbit was not affected by the presence of methionine. These findings suggest existence of differences in the specificity of gamma-GTP activity in these two species.

Amygdala↗
PubMed1979

The effect of dibutyryl cyclic AMP on cultivated glial cells from corpus callosum of 30-day-old rats.

1) Fragments of corpus callosum of 30-day-old rats were cultivated in Rose chambers. Mature astrocytes and predominantly differentiated oligodendroglial cells are present in the corpus callosum of rats at this age. 2) In vitro, astrocytes dedifferentiated into epithelial--like flattened cells, which highly adhered to the surface. Cells exhibited signs of phagocytosis, and their ultrastructure differed from differentiated cells, especially by the absence of microtubules and microfilaments. 3) After dibutyryl cyclic AMP (db-c-AMP) application, epithelial--like cells became rounded and multipolar. Cells were less liable to adhere to the surface. Bundles of microfilaments and microtubules appeared in cell perikarya and their processes. 3--4 hour after application, the morphological changes were well developed and disappeared after 24--48 hours. 4) It is being suggested that the increased intracellular concentration of db-c-AMP induced the formation of microfilamentous structures. The formation of the cyto-skeleton has a direct influence on the shape of cells and appearance of processes and cell adhesivity. 5) These results have demonstrated the high structural plasticity of mature astrocytes, their dedifferentiation in vitro and convertion into mature cells after db-c-AMP application.

Animals↗
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

Structure and ultrastructure of cultivated glial cells from Corpus callosum.

1. Explants and dissociated cells from Corpus callosum (c. c.) of rats and rabbits were cultivated in Petri dishes and Rose chambers. 2. Different types of glial cells were found in the cultivated Corpus callosum (c. c.) explanted from 12 days old rats: a) adendritic glial cells, typical for migrating oligodendroglial cells, b)-migrating large, nondifferentiated astrocytes with pronounced phagocytosing activity, c) macro- and microglial cells which differentiated during cultivation. 3. The population of differentiated glial cells is mostly composed of oligodendroglia, less of astrocytes and microglial cells are rare. 4. Differentiation of dissociated cells from c. c. in homogenous and mixed population was studied. The appearance of first processes of macroglial cells is postponed to 6 to 10 days of cultivation. No substantial difference was observed between homogenous and mixed population. A higher incidence of macrophages was observed in the later. 5. Glial cells differentiate surrounded by degenerated nerve fibers and myelin, exhibiting phagocytoses and cleaning reaction.

Animals↗
PubMed1978

Differentiation of corpus callosum glial cells and factors influencing their maturation in vitro.

1. Explants of Corpus callosum (c. c.) from 12-day-old rats were cultivated under different experimental conditions. 2. Migration and differentiation is activated by the presence of neighbouring explants, toward which glial cells predominantly migrate. Glial cells migrate if closely adhering to the supporting collagen and the process of differentiation is enhanced by presence of underlying cell layers. 3. Migratory activity of glial cells decreases and is delayed with age of donors. Migrating cells have a similar appearance as in cultures from 12 days old donors. The presence of immature types of glial cells in c. c. of adult animals was proved. 4. Glucose was found to be an adequate metabolical substrate, utilisation of glucose being lower than in cultivated neurons. In the absence of glucose or serum in the medium, neither migration nor differentiation of glial cells was observed. 5. The addition of embryonal extract and embryonic brain extract enhanced only initial stages of cell migration and differentiation.

Age Factors↗
PubMed1978

K+--induced changes of oxygen uptake by neuronal enriched and glial enriched fractions from mouse brain cortex.

Neuronal and glial enriched fractions were incubated in a medium with 10mM pyruvate, 5mM fumarate and 0.9mM 5'-AMP and the effect of increased external K+ concentrations was studied upon oxygen uptake. A concentration of 65 mM K+ had a different effect on the oxygen consumption of glial and neuronal perikarya. The rate of oxygen uptake by glia was stimulated by 52.81% whilst an insignificant decrease of 15.79% occurred in the neurones. The highest rate of oxygen uptake by incubated cells was estimated in the presence of the substrate system containing pyruvate, fumarate and 5'-AMP. The significance of components in the substrate system for a high rate of oxygen uptake by cells was also tested with 6.2 mM K+ and 65 mM K+.

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

Transplantation immunity in the brain.

The resistance of animals to allogeneic tumor cells injected into the brain increases with age. The second-set reaction in the brain of rats appears to be equally effective after preimmunization into the brain and preimmunization into the leg. Also, the presence of cytotoxic antibodies is demonstrable after preimmunization into the brain. These findings suggest that both arcs of the transplantation reaction, the afferent and efferent, are involved in tumor-cell allotransplantation in the brain.

Age Factors↗
PubMed1977

Experimental allergic encephalomyelitis. Water, sodium and potassium concentration in spinal cord and hemispheres and their changes after dexamethasone treatment.

Water content, Na+, K+ and Cl- concentration were measured in rats with experimentally produced allergic encephalomyelitis. Increase of water content by 10%, accumulation of Na+ by 13%, of Cl- by 20% and decrease of K+ by 10% was observed in the spinal cord, but no substantial changes were found in the brain tissue. The hydration of spinal cord is accompanied by perivascular infiltrates. Dexamethasone, administered from day 5, after injecting sensitising encephalitogenic basic protein, effects normal levels of water content and Na+, K+ and Cl- concentration.

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↗
PubMed1976

The metabolism of glucose of nerve cells cultivated under different conditions.

1. The consumption of glucose and formation of lactate was studied in medium of long-term cultivated nerve tissue. Fragments of chicken brain embryo dissociated and reaggregated brain cells were cultivated in Rose chambers, Falcon plastic dishes and Erlenmayer flasks. 2. Dissociated cells were cultivated in Petri dishes in media containing 100 mg/100 ml glucose. Consumption of glucose and formation of lactate increases until the 9th day. Glucose is completely exhausted in the medium up to the 2nd week of cultivation. 3. The time curve of both glucose consumption and lactate production is similar in cultures cultivated in Rose chambers, Petri dishes and Falcon plastic dishes. Cultures in Rose chambers utilize glucose at later stages anaerobically, whereas in Petri dishes and Falcon plastic dishes approximately 25% is utilized by aerobic glycolysis. 4. Cells dissociated by trypsinization and sieving are metabolically more active than cells separated mechanically (sieving only). During later stages of cultivation of enzymatically dissociated cells in 100 mg/100 ml glucose, lactate is utilized like a substrate, because of concentration of glucose in the medium is not being sufficient. 5. The concentration of glucose is essential for utilization by the aerobic pathway. In dissociated cells, cultivated in media enriched by 400 mg/100 ml of glucose in Falcon plastic dishes 75% of aerobic glycolysis is found during first 10 days and 50% in later stages. In the same system, cultivated in 100 mg/100 ml of glucose, glucose is exhausted up to the 12th day and lactate is utilized as a substrate. 6. In the close system of cultivation, i.e. in Rose chambers, 50% of glucose is utilized by the aerobic pathway if the medium contains 400 mg/100 ml of glucose. Early cultivation period of dissociated cells in Falcon plastic dishes is slowed, because cells adhere slowly to the plastic ground. 7. Structural development of cultures and differentiation of cells was studied during the cultivation period. Cells cultivated in elevated glucose concentration exhibit signs of better differentiation.

Aerobiosis↗
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↗