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C Alexandru

Publications and source records attributed to C Alexandru.

8 recordsLinked to original sources
PubMed1975

[Stratification in the central nervous system].

Stratigenesis in the optic tectum of developing chick embryos was investigated between the 4th and the 11th day of incubation. Stratification is achieved by successive emigration of cell contigents from the proliferative layer. In the opinion of the authors the main factor which determines this very regular cell migration would be a gradient of oxygen and of metabolites. The gradient has to appear in the wall of tectum due to its typical vascular network. Experiences with induced hypoxia or with selective damage of the proliferative layer strengthen the hypotesis of an oxygen gradient playing the role of a generally active epigenetic factor in the stratigenesis of the central nervous system.

Animals↗
PubMedDate not supplied

[Analysis of attitudes about abortion].

Today two clear trends can be discerned in the development of attitudes about abortion over the last century or so. The first corresponds to that category of "bio-power" described by Foucault as a bio-politics of the population. The second trend, closely related, concerns the transformation of abortion from a largely criminal to a largely therapeutic procedure, that is, one which is said to be performed in the interests of preserving or enhancing the health and well-being of the woman or her existing children. This paper analysis the attitudes about abortion exploring the responses of the Medical Bioengineering Faculty's students to a series of questions about the conditions under which legal abortions should be available and tried to identify some of the reasons why abortion attitudes vary from person to person.

Abortion, Induced↗
PubMedDate not supplied

[Stratification in the central nervous system].

In the authors' opinion the neuroblasts (glioblasts respectively) are moving along an oxigen-gradient, out of the proliferative layers toward the source of O2 (the vascular plexi). Stratigenesis is influenced by "guiding structures" (fibrillar plate in the tectum opticum), by the elongations of ependymal cells and by the similarly oriented vascular-connectives.

Animals↗
PubMedDate not supplied

[Fine-structure and function of the primary proliferative layer of the embryonal central nervous system].

Results obtained by mechanical isolation of neuroblasts from the primary proliferative layer of the central nervous system in chick embryos by the aid of an original method and by electronmicroscopic investigations are consistent with Sauer's concept on neuroepithelial cell proliferation. The bipolar form of the undifferentiated neuroblast is maintained--at the beginning--by external factors of cell contact only. Each end-feet contains two centrioles, one of which represents the basal body of a cilium. During mitosis, the position parallel to the lumen of the spingle axis and the subsequent appearance of two identical daughter cells depend on the behaviour of the centrioles. The later may move in an abnormal direction, and induce thus an obliquely or perpendicularly laying spindle axis. These changes may influence--on the other hand--the mechanism of proliferation.

Animals↗