In previous papers (1, 2), it was shown that in the rat fetus, testicular differentiation begins 13 days after fertilization, in the depth of the primordium near to mesonephric tubules. A few cells swell and differentiate into Sertoli cells which encompass the germ cells. In the meantime they delineate locally one part of the contour of the developing seminiferous cord, which is completed by the recruitment of new cells during the next hours. Under the electron microscope the differentiation of the Sertoli cells involves cytoplasmic and organelles changes, typical junctions and microfilaments toward the external surface of the seminiferous cord. Testicular differentiation can be obtained in vitro in cultures made in a synthetic medium without or with addition of chick embryo extract. Fetal calf serum prevents the organogenesis of the sex cords or produces the disintegration of those already differentiation (on day 14). These data clearly underline some of the cellular processes involved in the differentiation of the seminiferous cords.

Animals↗

PubMedDate not supplied

Congenital dyserythropoietic anemia type II. Radioautographic, ultrastructural and cytogenetical study in two familial cases.

The case of two sisters is reported in whom morphological (multinucleated erythroblasts in the bone marrow) and serological (positive Ham test, negative sucrose and water-sugar tests) characteristics of a congenital dyserythropoietic anemia type II were found. Radioautographic, cytogenetic and electron microscope studies confirmed the presence of an inefficient erythropoiesis and of a membrane defect, common in this disease. The finding of a nil LAP score has never been reported so far.

Adolescent↗