Genetic polymorphisms and intrauterine development. Evidence of decreased heterozygosity in light-for-dates human newborn babies

Summary In 2 independent samples of low-birth-weight infants the proportion of females and homozygotes for a series of polymorphic systems was higher in light-for-dates than in preterm babies. The observation seems to give support to the hypothesis that homozygosity for normal polymorphisms may decrease in general intrauterine growth rate. Since it is known that survival rate is strongly related to birth weight, a correlation between growth retardation and homozygosity may have a major role in the maintenance of such polimorphisms.We thank Prof. L. Ginzburg for helpful comments.     

Developmental homeostasis and heterozygosity for blood group loci in a human population

Summary Relationship between the variability of 5 independent morphological characters and the heterozygosity level at 4 blood group loci were determined in Israel. An increase in the heterozygosity level led to a reduction of the range and coefficient of variation of the morphological traits and also led to an increase of modal phenotype frequencies in the group.We are very grateful to Professor B. Arensburg of our department at the Tel Aviv University for his kind permission to use anthropometric data collected by him.     

Follicles development in the foetal human ovary.

In the foetal human ovary, diameters of oocyte and follicle, as well as those of oocyte and nucleus, are found to be positively and linearly correlated with each other. Follicle diameter and number of granulosa cells also show a positive and linear relationship. Finally, in all ovaries examined, from 5 months after conception onwards, small antral follicles were assessed.     

Catecholamine levels in newborn human plasma in normal and abnormal conditions and in maternal plasma at delivery.

High levels of catecholamines have been found in plasma from the umbilical cord of newborn infants, suggesting a release of catecholamine from the fetus during parturition. Plasma catecholamine levels are also elevated in mothers at delivery.     

Heterotransplantation of human glioblastoma in the brain of newborn mice]

7 human multiform glioblastoma have been transplanted into the brain of 100 new born Mice. Electron microscopy and chromosome analysis confirm the growth of a human tumor showing malignant features of glioblastoma.     

Catecholamine levels in newborn human plasma in normal and abnormal conditions and in maternal plasma at delivery

Summary High levels of catecholamines have been found in plasma from the umbilical cord of newborn infants, suggesting a release of catecholamine from the fetus during parturition. Plasma catecholamine levels are also elevated in mothers at delivery.     

Rotavirus and gastroenteritis in the newborn infant. Initial observations]

A simplified method for the diagnosis of Rotavirus by electron microscopy is presented. The incidence of these viruses is observed in new-born infants and the relationship with acute gastroenteritis is recalled.     

Genetic engineering in the adaptation of plants to evolving human needs

Cellular and Molecular Life Sciences -     

Differentiation of human megakaryocytes in culture starting from the primordial circulating cells in the newborn]

Human neonatal blood mononuclear cells were seeded in plasma clot containing high dose of a crude erythropietin. Pure megakaryocyte colonies were observed rarely and most of the colonies were mixed, megakaryocytes being located between subcolonies of erythrocytic bursts. The megakaryocytic nature of large cells could be clearly confirmed by the presence of platelet peroxidase, demarcation membranes, and alpha granules detected by electron microscopy; in addition mature micromegakaryocytes were recognized, shedding platelets.     

Sensitivity of follicular melanoblasts in newborn mouse skin to tritiated thymidine: Evidence for a long term retention of label

Summary Injection of tritiated thymidine into newborn mice results in a progressive greying of hair that does not begin until after the first hair coat is grown. After a year the depigmentation is appreciable (about 60% of the hair are white). The effect cannot be simulated by external irradiation of newborn mice or by the administration of radioactive uridine or methionine. The effect can best be explained by a long-term retention of radioactivity in the DNA of melanocyte stem cells (melanoblasts) in spite of several rounds of cell division. This could be achieved by labelling the strands of DNA destined to act as templates throughout life by being selectively retained in the stem line as described in Cairns' hypothesis.Acknowledgments. This work was supported by grants from the Cancer Research Campaign. I am indebted to Joan Bullock for her careful, patient help with these experiments. CSP is a fellow of the Cancer Research Campaign.     

Genetic models in brain and behavior research. Part III

The Editors of Experientia wish to thank Dr P. Driscoll for coordinating this multi-author review.     

Influence of light on the plasma gonadotropin concentrations in the newborn rat.

The physiological increase in plasma gonadotropin (LH and FSH) levels in newborn rats is indisputably influenced by light. Permanent illumination accentuates this increase, whereas darkness decreases it in 16-day-old female rats. In male rats of the same age, only permanent illumination was tested with the same results.