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Biomedical subjects

L Bologa

Publications and source records attributed to L Bologa.

26 records · Page 2Linked to original sources

Development of immunologically identified brain cells in culture: quantitative aspects.

Mechanically dissociated brain cells of 14 and 18-day-old mouse embryos and of mouse neonates were cultured for 3 weeks. Neurons, oligodendrocytes and astrocytes were identified at the 7th, 14th and 21st day in vitro by staining the cultures using the indirect immunoperoxidase technique with antisera directed against neuron specific enolase, galactocerebroside, myelin basic protein and glial fibrillary acidic protein. The number of neurons and oligodendrocytes was higher in embryonic cultures than in neonate cultures. The expression of some antigens was also different in the two types of culture. Our results indicate that the development of brain cells in mechanically dissociated brain cell cultures depends on the age of the animal at the time of plating.

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Accelerated differentiation of oligodendrocytes in neuronal-rich embryonic mouse brain cell cultures.

The expression of two oligodendroglial markers, galactocerebroside (GC) and myelin basic protein (MBP), was studied in brain cell cultures (BCC) from 14-day-old mouse embryos by immunocytochemical methods. The presence of neurons and astrocytes was also investigated. Results show that oligodendrocytes simultaneously express both GC and MBP already at 7 days in vitro. These cultures are rich in neurons, and the astrocyte layer is also well represented. A comparison is made between these data and those previously obtained by the use of newborn mouse brain cell cultures, which are very poor in neurons. The differentiation of oligodendrocytes, as reflected in the expression of MBP, is accelerated in embryonic mouse BCC when compared to neonatal mouse BCC. We therefore speculate that neurons are involved in the enhancement of the ability of oligodendrocytes to express myelin related components in culture.

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Viral tropisms in mouse brain cell cultures.

Fourteen-day-old cultures of dissociated newborn mouse brain cells were infected separately with different strains of vaccinia virus and a strain of measles virus. Using the indirect immunofluorescence technique we found that under the experimental conditions in these cultures both measles and the neurotropic strain of vaccinia infected oligodendrocytes whereas the dermatropic strain of vaccinia did not. Astrocytes were neither infected by vaccinia strains nor by measles virus.

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Relative changes in the amount of galactocerebroside during development as observed in mouse brain cell cultures.

Relative changes in the amount of galactocerebroside (GC) during development were measured in mouse brain cell cultures at different stages of development. For this purpose we used an 125I-labelled protein A indirect assay modified in the respect that the total amount of cellular proteins was evaluated before counting the radioactivity. The amount of GC greatly increased between the 10th and the 14th day of culture, then a steady state was reached between the 14th and the 20th day of culture. This change correlates well with the dynamics of the number of oligodendrocytes we observed earlier. These data suggests that the increase of the GC amount in culture during development corresponds to the increase in the number of GC-positive oligodendrocytes rather than to the increase in the number of GC molecules per cell.

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Some data concerning immune processes in concomitant tumor immunity experimental models. Comparative in vivo and in vitro investigations II. In vitro experiments.

The humoral and cellular immune status of C57BL/6 male mice and "R" male rats bearing MC-induced sarcomas were investigated in vitro, using 51Cr-releasing and mixed hemadsorption assays. Analysis was performed on mice subjected to concomitant tumor immunity (CTI) model experiments or bearing primary tumors of different sizes, that was done also in rats. Chromatographic fractions, assumed to contain tumor specific antigens, antibodies or antigen-antibody complexes were identified by their absorption capacity upon specially prepared syngeneic immune sera. Free antibody and antigen-antibody complexes, accompanied with a weak cell mediated immunity (CMI) were correlated with efficient CTI in 2--3% TW/TBW tumor bearers. Homoral immunity (HI) showed sometimes an important increase after challenge administration. High levels of free antigen and antigen-antibody complexes, lack of antibodies and CMI were correlated with CTI absence in huge tumor bearers, representing 30--37% of total body weight. Conditions determining variability of results reported by different authors and the possible mechanisms by which serum immune factor may impair the tumor bearer's immune status are discussed.

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Proliferation rate of oligodendrocytes in culture can be influenced by extrinsic factors.

We investigated whether in cultures of mechanically dissociated brain cells from newborn mice the reduction of the number of oligodendrocytes influences their proliferation rate. 14-day-old cultures were subjected to complement-dependent anti-galactocerebroside (GC) antibody-mediated cytotoxicity. The cytotoxic treatment completely destroyed oligodendrocytes. Thereafter, GC+ oligodendrocytes progressively reappeared. Their number was 20 and 66% compared to controls, 3 and 7 days after cytotoxicity, respectively. Proliferating oligodendrocytes were detected 3 and 7 days after cytotoxicity by combining the immunostaining for GC with 3H-thymidine autoradiography. The proliferation rate of oligodendrocytes in treated cultures was increased by 100 and 76% compared to controls, 3 and 7 days after cytotoxicity, respectively. These data suggest that the proliferation rate of oligodendrocytes can be influenced by extrinsic factors.

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