Proliferative activity and characteristics of immunocytochemically identified oligodendrocytes in embryonic mouse brain cell cultures

Dissociated brain cell cultures of 14-day-old mouse embryos (E 14) were used for studying, during development, the proliferative activity of oligodendrocytes which express myelin basic protein (MBP) and galactocerebroside (GC). This was done using a combination of 3H-Thymidine autoradiography and immunoperoxidase or immunofluorescence. Quantitative estimates of labeled cells were made using a Leitz Texture Analysis System (T.A.S.) coupled to a P.D.P. 11-34 minicomputer. Results showed that differentiated oligodendrocytes, which express both MBP and GC, are able to proliferate. According to the intensity of the immunostaining, strong MBP positive and weak MBP positive oligodendrocytes were observed. Only the weak MBP positive cells incorporated 3H-Thymidine. The highest percentage (22.5%) of 3H-Thymidine labeled oligodendrocytes was observed at day 6 in vitro, and was reduced by half at day 9 to 13. Oligodendrocytes which have undergone a first division are still able to proliferate.     

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.     

Myelination in rat brain aggregating cell cultures.

Aggregates of fetal rat brain were maintained in rotating culture for 30–40 days and were analyzed morphologically and biochemically. At 4 days in culture all cells were undifferentiated. At 26 days in vitro over 90% of all cells within the aggregates could be identified as neurons, astrocytes or oligodendrocytes. Myelinated axons and morphologically mature synapses were present at 26 days. Myelination started between 18 and 19 days in culture as determined biochemically. Myelin basic protein sulphatide synthesis and 2′,3′-cyclic nucleotide 3′-phosphohydrolase activity increased with in vitro age. The amount of myelin observed within the aggregates was much lower than observed at the corresponding age in vivo. Neurons and neuronal processes were undergoing severe degeneration in the 40-day aggregates and synaptic contacts were not maintained. There were no normal myelinated axons at 40 days although multilammellar membranes were found intra- and extracellularly. The ganglioside pattern of the aggregates were qualitatively similar to rat whole brain. Quantitatively the G_M3ganglioside was elevated in comparison to whole rat brain.Our results indicate that aggregating rat brain cultures provide a useful in vitro system for the biochemical and morphological analysis of myelin formation.     

Morphine treatment increases clonidine binding in brain cell cultures

Exposure of murine brain cells in culture to 75 μM morphine for 6 days produced an increase in the number of [³H]clonidine binding sites without affecting the apparent affinity. Similar treatment increased the binding of this α₂-adrenergic receptor agonist to cell cultures prepared from cerebral cortex but not to cultures of brain minus cortex or to neuroblastoma-glioma hybrid cells which possess both opiate and α₂-adrenergic receptors.     

Growth of JC virus in adult human brain cell cultures

Summary Adult human brain (AHB) cells infected with JC virus (JCV) developed a cytopathic effect (CPE) beginning 12–14 days after infection. Ultrastructurally, 37–40 nm papova virions were seen in the nuclei of infected cells, and both T and V antigen were demonstrated by indirect immunofluorescence. The hemagglutinating titer of JCV in infected AHB cells was 10–40 times higher than the amount of JCV used to initiate infection. AHB cells are more readily available than primary human fetal brain cells, they can be subcultured 15–25 timesin vitro and they support JCV replication after multiple subcultivations. These properties make the AHB cell line useful for propagating JCV.With 3 Figures     

Qualitative and quantitative studies on mixed homologous chicken thymus cell cultures

The proliferative interaction of mixed homologous chicken thymus cells was studied in a serum-free culture system using thymus cell populations from thymus glands that had been experimentally manipulated to yield varying proportions of lymphocytes from the medulla and cortex of the gland. It could be demonstrated that the proliferative responsiveness of thymus cells to immuno-genetically different cells resided with the lymphocyte population located in the medulla of the thymus. The capability of medullary thymus cells to participate in a mixed lymphocyte interaction (MLI) was found to be nearly equal to that of splenic lymphocytes. The in vitro survival of medullary thymus cells was markedly superior to cortical thymus cells. Kinetic studies with medullary thymus cells revealed that the proliferative response in the MLI was initiated during the first 24–40 hr culture period and generally reached its peak 4 days after culture initiation. It could be demonstrated that responding cells were capable of several repeated divisions. In addition, previously nondividing cells entered the reaction for the first time up to the 3rd and possibly 4th day after culture initiation. Calculations revealed that 0·7–1·9% of the original viable thymus cell population participated in the response. It was also calculated that peripheral blood lymphocytes contaminating the thymus cell populations of both cell donors contributed less than 1% to the total number of responding thymus cells. When the response of mixed homologous thymus cells was compared in a chemically defined and serum containing medium, striking differences in the time course and magnitude of the reaction were seen. It could be shown that the viability and proliferation of thymus cells was adversely affected by serum and markedly enhanced by insulin supplementation to a chemically defined medium.     

Growth of murine cytomegalovirus in murine and heterologous brain cell cultures

Summary Murine cytomegalovirus (MCMV) produced a cytopathic effect in mouse brain, guinea pig embryonic brain, human brain and fibroblast cells. Virus-specific antigen was detected by immunofluorescence in these cells after primary infection with MCMV. MCMV also replicated in mouse embryo brain and guinea pig brain cells. Although definite evidence of MCMV replication could not be demonstrated in human cells, MCMV infectivity was maintained for 12 days in human cell cultures.With 3 Figures     

Persistent infection of measles virus in mouse brain cell cultures infectedin vivo

Summary Cell lines have been established from measles infected mouse brains. They grow more readily than do cultures from similar uninfected animals and cytoplasmic inclusions, typical of measles, are present in H and E stained preparations. Minimal amounts of measles virus can be isolated from the culture fluids and measles infection in a proportion of the cells can be demonstrated by immunofluorescence. No detectable interferon is produced and the cells are not damaged by measles antiserum and complement.     

Cytogenetic studies of primary cultures of esophageal squamous cell carcinoma

Cytogenetic analysis was performed on primary cultures of 21 squamous cell carcinomas of the esophagus (SCCE). Seven cases exhibited mosaic clonal chromosome abnormalities distributed as follows: two contained tetraploid cell populations, one with t(3;7)(p21;q11); two showed loss of the Y chromosome, one with double minutes; single cases demonstrated der(11)t(4;11)(q?27;q23); add(1)(p35) and del(4)(p12); and del(7)(p13), del(7)(q22q34), and der(11)t(7;11)(p?15;p?13). The remaining 14 cases had apparently normal karyotypes, possibly derived from stromal elements. These results demonstrate numerical abnormalities and the multiple occurrence of rearrangements involving chromosomes 7 and 11 in SCCE.     

Ultrastructural studies of the replication of fowl adenoviruses in primary cell cultures

The replication of four fowl adenovirus strains (FAV-1, strain Phelps; FAV-5, strains 340 and TR-22; and FAV-7, strain YR-36), in primary chick kidney cell cultures, is described. Differences were found in the distribution of virus particles and virus associated inclusions between viruses belonging to different cytopathology subgroups. Thus in cells infected with FAV-1 (Phelps) and FAV-5 (340) (i.e. subgroup 1) virus particles, as they increased in number, tended to become distributed peripherally, close to the nuclear membranes, with the virus associated inclusions in the centre of the nucleus. With FAV-5 (TR-22) and FAV-7 (YR-36) (i.e. subgroup 2) virus particles and associated inclusions became concentrated initially in the central nuclear area later increasing to fill the whole nucleus, with virus particles and inclusions completely intermixed. The virus-associated inclusions were found to be identical to those described in human adenovirus infected cells and the same nomenclature was adopted. Other inclusions found in infected nuclei, included tubular structures and inclusions composed of granular particles.     

Myocardial electrophysiology: intracellular studies on heart cell cultures from newborn rats.

Electrical properties of cultured newborn rat heart cells are investigated by the use of microelectrophysiological methods. Amplitudes of resting and action potentials appear close to those of in situ heart cells. Elevated spike rate of rise reveals functional fast sodium channels. An inconstant ratio of cells exhibit pacemaker-like activity but no relationship can be established between this automaticity and the tissular origin of the cultured cells. The pulsation rate appears to be linked to the action potential duration and to the pace-maker potential slope. Spontaneous arrhythmias may occur; they are mainly caused by anomalous conduction and (or) erratic pacemaker driving. Thus heart cell cultures may be considered as a precious tool in the field of the cardiac electrophysiologal and physiopathological studies.