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Biomedical subjects

J Hubert

Publications and source records attributed to J Hubert.

At least 199 records · Page 11Linked to original sources
PubMed1976

[Electron microscopy of ameboid oocytes in the lizard: Lacerta vivipara J].

Oocytes at diplotene stage showing a very distinct amoeboid morphology have been observed in the germinal bed of young females. The oocytes produce long pseudopodial formations which extend between the somatic cells. This morphology suggests an autonomous progression of the oocytes which seem to migrate by amoeboid activity towards the area of the germinal bed situated near the ovarian cavity. The increase of the number of the follicular cells which join the oocytes might contribute to stop the amoeboid movements.

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PubMed1976

[Ultrastructural study of the piriform cells of the ovarian follicle in 5 reptiles].

In the 5 Lacertilians the cytoplasm of the pyriform cells contains numerous mitochondria, a well developed Golgi apparatus, free ribosomes, glycogen-like particles, annulate lamellae, bundles of microfilaments and microtubules. Both the paracrystalline arrangement of ribosomes in Lacerta muralis and Lacerta viridis and the paracrystalline intramitochondrial inclusions in Anguis fragilis observed during the spring are probably related to hibernation. Each pyriform cell is connected to the oocyte by a cytoplasmic bridge which occurs secondarily between the two types of cells. Therefore the pyriform cells and oocyte constitute a syncytium. It is possible that the cytological similarities between the pyriform cells and the oocyte and the degeneration of the pyriform cells result from this syncytial state. The nucleoi do not have the same ultrastructure in the 5 Lacertilians; differences are noted in the dense fibrillar constituant and the composition of the nucleolus varies. The "paranucleolar body" is present in 4 Lacertilians but absent in Lacerta muralis.

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PubMed1976

[Ultrastructure of the gonadal primordia of the viviparous lizard (Lacerta vivipara Jacquin) during the period of colonization by the germ cells].

This ultrastructural study was carried our during colonization of the gonadal primordia by the germ cells which reach the gonads after interstitial migration. During the period of colonization, the germinal epithelia have no basal membrane. The epithelial cells are linked together by desmosomal junctions; they contain many free ribosomes, some lipid droplets, few granular reticula. The Golgi apparatus and the agrangular reticulum are well developed and situated at the distal pole of the cells. The outline of the germinal epithelia is regular in front of the coelomic cavity. At first, the outline of the basal surface is very irregular because the epithelial cells put out many cytoplasmic processes. Then, cytoplasmic processes become more sparse and the outline of the basal surface more regular. The germinal epithelia do not show swellings linked with a merocrine type of excretory process as in the chick (Cuminge and Dubois, 1971). However, this does not rule out a chemotactic type attraction of the germ cells. The first germ cell which arrive in the gonadal areas are incorporated into the epithelia. Later on, the germ cells are immobilized by the mesenchymal cells of the gonadal primordia which prevent them from reaching the epithelia. These germ cells stay in the medullary area of the young gonad which contain a greater number of germ cells than the epithelia.

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PubMed1976

[Survival of parasitic elements in liquid manure: effect of xylene (author's transl)].

The spreading of liquid manure may play a role in the transmission of parasitism. In this preliminary study, we have investigated the evolutionary and survival capacities of parasitic elements in liquid manure, their development potential after extraction and the destructive action of xylene in concentration of 1 p. 1000. As parasitic models we have retained: the coccidial oocyst (E. tennella), a thick-shelled egg (A. suum), thin-shelled eggs (H. contortus, O. quadrispinulatum), a trematode egg (F. hepatica) and larva III of H. contortus. The studies were carried out in Erlenmeyer with parasite free liquid manure taken from a bovine cowshed. Water was used as control medium. The parasitic models were kept in the liquid manure for a maximum of 17 days excpet for Ascaris suum, 45 days. Only the coccidial oocyst is little affected. The eggs of Trichostrongylides and of Fasciola show a poor resistance to this environment and to a lesser degree the egg of Ascaris. The larvas III are rapidly destroyed and those obtained from eggs that stayed in liquid manure have a greatly diminished viability. The antiparasitic action of xylene varies according to the type of parasitic element. Its action is particularly clear on the eggs of Trichostrongylides and of Fasciola hepatica.

Animals↗
PubMed1975

[Description, cytochemistry, and electron microscopic autoradiography of nucleolar granular spheres and micronucleoli of lizard (Lacerta vivipara Jacquin) pyriform cells].

The granular spheres are constituted of granules of 300-350 A and show a higher contrast than the nucleolar part where they are localised. The micronucleoli consist of fine fibrils. These two structures contain RNP. A relation between the granular spheres and the degeneration of the pyriform cells is suggested. The RNP of the micronucleoli, probably synthesized on perinucleolar DNA, migrate into cytoplasm.

Animals↗
PubMed1974

[Ultrastructure of primordial germ cells of Lacerta muralis and Lacerta viridis. Comparison with Lacerta vivipara (author's transl)].

The ultrastructure of primordial germ cells migrating through the embryo and situated in genital crests is described in Lacerta viridis and Lacerta muralis. It is compared with the germ cells of Lacerta vivipara previously studied. The cytoplasmic ultrastructure is the same in the three Lacertilians, but several nuclear differences are observed. The outline of the nucleus is regular and his shape is spheric in Lacerta vivipara, but in the two others Lacertilians the nucleus shows a very sinuous outline with deep cytoplasmic invaginations. There are fibrous nuclear bodies in the three Lacertilians but the germ cells of Lacerta muralis have in addition granular bodies. The nucleolus in Lacerta viridis and Lacerta muralis is very different from the annular nucleolus of the germ cells of Lacerta vivipara. It is possible to distinguish three types of nucleoli: a compact nucleolus in Lacerta viridis and Lacerta muralis, a granular cords nucleolus in Lacerta viridis, a vacuolar nucleolus in Lacerta muralis. Each type can be seen during the migration of the gonocytes or during the colonisation of the genital region. Probably there is a relationship between these different architectures and the activity of nucleolus in synthesis and liberation of ribosomal RNA. However the nuclear fibrillar area which we have previosly called "masse para nucléolaire" in Lacerta vivipara, is present in the germ cells of Lacerta viridis and Lacerta muralis.

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