ISSN:
1432-2099
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Biologie
,
Physik
Notizen:
Summary Autoradiographic studies were conducted at the cerebral hemispheres of mouse embryos X-irradiated on day 12 of gestation and of normal litter mates during the subsequent developmental period. By counting the percentage of labeled mitoses the generation time, the potential doubling time, the growth fraction, as well as the length of the individuall cell cycle stages of the neuroblast cells were determined. A continuous increase of generation time was found in the normal brains, concomitant with a latteo-medial gradient in telencephalic wall differentiation progress. After X-irradiation this normal differentiation pattern still prevails, but with some marked topographical pecularities. The most important finding was a significant lengthening of the generation time at the medially situated rudiments of the ventricular zone and, similarly at the heterotopic cell islets located within the intermediary zone. Concomitant with this effect, which was seen mainly on days 15 and 17 of gestation, there was a marked increase of mitotic time of these special neuroblasts. The latter finding was regarded as a random event only, which has no causal relationship to the pathogenesis of the heterotopic islets or similar overgrowth anomalies after X-irradiation. In spite of the long generation time of these his tological pecularities, they make a considerable contribution to the regeneration of the injured telencephalic wall: Up to day 15 of gestation the heterotopias had a growth fraction of nearly 1.0 (= 100%), whereas the percentage of proliferating cells within the orthotopic remainders of the ventricular zone was only 44%.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF01338889
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