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Biomedical subjects

G Tedde

Publications and source records attributed to G Tedde.

39 records · Page 3Linked to original sources

The sertolian epithelium in the testis of men affected by 'Sertoli-cell-only syndrome'.

Because of the architectural complexity of the seminiferous epithelium, the Sertoli cell is extremely difficult to study. The individual cellular constituents of the tubular wall are intimately associated with one another; especially Sertoli cells and germinal cells are tightly connected. As implied by the name, Sertoli-cell-only syndrome (SCOS) is characterized by the presence of only Sertoli cells in the seminiferous tubule. The absence of germinal cells makes this condition ideal for the morphological study of Sertoli cell. Testicular biopsy specimens of subjects affected by SCOS were studied under light and electron microscopy. The Sertoli cells appeared to be morphologically normal, except for their shape, that appears to be columnar as result of the complete absence of the germinal cells. The cellular outlines were irregular, particularly at the base, but the cytoplasm contained normal organelles and inclusions. The presence of both pale and dark elements was evident. These differences in staining reflect the variability in concentration of glycogen particles and intermediate microfilaments in the cytoplasm. In spite of these differences between Sertoli cells in SCOS and those in normal subjects, SCOS represents a satisfactory model for the morphological and functional analysis of the Sertoli cells.

Actin Cytoskeleton↗

The human gonocytes in the early phases of gonadal differentiation. Observations of one embryo at Carnegie stage 11.

With the aim of emphasize the characteristics of the migration of human primordial gonocytes through the mesenchyme of the dorsal mesentery towards the genital ridge, a very early human embryo, corresponding to Carnegie stage 11 (23-24 days of development) was studied together with other embryos from the 4th to the 10th week of pregnancy. The early embryo was embedded in resin, serially cut and the observations were made on semithin coronal sections, de-plasticized and stained with toluidine blue. Migrating primordial germ cells were identified in the thickness of the splanchnopleure, where they appeared as pale and round elements with a nucleolated nucleus and granular cytoplasm. The clusters of primordial gonocytes were constantly surrounded and in close relationship with smaller, polyhedral and intensely stained elements. These features suggest the hypothesis that gonocytes and dark cells join together during the process of migration and that the last can participate in the formation of the gonadal bud. The hypothesis is confirmed by the observation of dark cells, surrounding the gonocytes, in the primitive ovaries or testes, in later stages of development. Perhaps they do not participate directly in the formation of the sexual cords, but reach their periphery where they assume an elongate shape.

Cell Movement↗

Nuragic bone collagen retains its molecular structure.

The molecular structure of bone collagen was found to be preserved in Nuragic bone samples several centuries after burial. Enhanced birefringence of bone and dentin collagen fibres observed in polarized light after Sirus red staining was used to demonstrate this fact.

Anthropology, Physical↗