PubMed Health⌕ Search

Biomedical subjects

L Gomot

Publications and source records attributed to L Gomot.

At least 37 records · Page 2Linked to original sources
PubMed1978

Changes at the ecto-mesodermal interface during development of the duck preen gland.

An ultrastructural investigation of the organogenesis of the duck preen gland showed variations at the ecto-mesodermal interface in the course of development. During the period of invagination, ectoderm and mesoderm were separated by a continuous basal lamina. Morphogenesis of the tubules is characterized by a preferential deposition of non-oriented collagen fibres localized at the branching sites. Direct contacts between ectodermal extensions and mesodermal cells, through gaps in the basal lamina, appeared at the end-buds after the morphogenetic pattern was established and before the onset of the glandular secretory activity. The correlation between the modification of the ecto-mesodermal interface and the differentiation of uropygial ectoderm is discussed.

Animals↗
PubMed1977

[Effects of alpha-amanitin on the development of Xenopus (Xenopus laevis Daud.) heart in vitro].

The differentiation of Xenopus heart is studied in vitro, in the presence of alpha-amanitin. The results obtained depend on the concentration of the inhibitor, the length of treatment and the stage of primordium. The mRNA pool assures the differentiation of explants, removed from young stages, for 12 hours. This time is half for the primordia removed from stages greater than 3,5 mm.

Amanitins↗
PubMed1977

[Differentiation of the prostate in the snail Helix aspersa Müll].

The differentiation of the snail Helix aspersa prostate gland is studied in animals from one to six months old. After the presentation of organogenesis the primary stage of secretion (3 months) and a stage where the prostate gland shows abundant secretions (6 months) were described; but the oviduct is still indifferentiated. The ultrastructural analysis shows the formation of secretory and ciliated cells in epithelioid prostatic tubes.

Animals↗
PubMed1977

[Autoradiography after tritiated thymidine labeling of the abortive gametogenesis in hybrid male ducks from the cross male Pekin X female Barbary].

This autoradiographic data concludes that meiotic prophase of the abortive gametogenesis of the sterile hybride drake (from the mating Peking male = Anas platyrhynchos L. X Barbary female = Cairina moschata L.) lasts 5 days 1/4. 6 days after the injection of the marker the seminiferous tubules contain numerous labeles necrosing cells but never typical elongated spermatids.

Animals↗
PubMed1977

[The steroidogenic sites in the Peking, Barbary and hybrids (Peking male X Barbary female) ducks: histochemistry, ultrastructure, biochemical complements (author's transl)].

The follicular theca steroid cells are much more numerous in the Peking female than in the Barbary female. Biochemical analyses show that the transfromation percentage of pregnenolone in progesterone is higher in the first than in the second (73% greater than 52%); in the same way, we dose more plasmatic oestradiol in the Piking than in the Barbary female (160 pg/ml greater than 69 pg/ml). In the hybrid female, resulting from the crossing of Peking male X Barbary female, many steroid cells are destroyed during the aging process; the transformation percentage in then 14,50% (30% in the young females) and the seric concentration is 7 pg/ml (59 pg/ml in the young females).

Animals↗
PubMed1976

[Abortive spermatogenesis in the hybrid duck (cross of male Anas platyrhynchos and female Cairina moschata). Ultrastructural study].

The ultrastructural study of the abortive spermatogenesis of the hybrid drake (cross: male Anas platyrhynchos L. X female Cairina moschata L.) shows the following characteristics: 1) deep anomalies during the pachytene stage (meiotic prophase) where the chromosomes form more or less irregular packs close to the nuclear enveloppe; 2) the total lack of 2nd spermatocytes and in their place were found: --either some cells with lobed or fragmented nuclei in a cytoplasm filled with numerous annulate lamella, lipid droplets and centrioles, --or necrosing cells, with vacuolised chromatin close to the inner side of the nucleus and with abundant smooth endoplasmic reticulum vesicles and dark mitochondria; 3) numerous Sertoli cells overloaded with lysosomes. The mitochondria of the spermatogonia, the basal membrane of seminiferous tubules and the Leydig cells have the same structure that exists in the fertile Barbary drake testis.

Animals↗
PubMed1976

[Ultrastructure of 3 beta HSDH (delta 5-3 beta hydroxysteroid dehydrogenase)-containing cells in ducks. III. Hybrid ducks (Anas platyrhynchos male X Cairina moschata female) during egg laying].

All the cells of the ovary of the hybrid duck (Peking duck X Barbary duck) which contain an active 3 beta HSDH enzyme show ultrastructural characteristics of steroid cells: a smooth, developed reticulum, tubularcrested mitochondria, a considerable "charge" in lipid inclusion. These cells are found not only in the internal theca of follicles as with the female gender, but also in the cortical zones void of germinal elements, a tendancy particular to the female.

Animals↗
PubMed1975

[Comparative study on the ultrastructure of the primary mammary bud of male and female embryos at the stage of sexual differentiation].

The observation of embryonic mammary glands in male and female mice under the electron microscope has shown on one hand that the cellular ultrastructure of the buds is characterized by embryonic tissue only slightly differentiated, and on the other that, under the influence of testicular hormone, the detachment of the anlage from the epidermis in fourteen-day old embryos results in an important modification in the relationship between the ectoderm and the mesenchyme at the level of the neck of the gland rudiment. The basal membrane is destroyed and numerous centers of necrosis can be seen starting from the dense bodies in the ectodermic cells of the ruptured zone.

Animals↗