Biomedical subjects
Publications and source records attributed to A Raynaud.
Administered to eggs of Reptilia (Lacerta viridis and Anguis fragilis), cytosine-arabinoside induced numerous embryonic malformations, among which microphthalmia and limb deformities. On the other hand this drug delayed the retrogression of the apical ridge of the limb buds in Anguis fragilis.
Glucocorticoid receptors (RG) and mammary tumor virus (MM-TV) DNA sequences were extracted by micrococcal nuclease digestion from the nuclei of C3H mouse mammary tumor cells in order to specify their relative distribution in chromatin. RG was labelled and translocated into the nuclei by incubating cells with 3H Dexamethasone (3H Dex). The purified nuclei were then treated at 2 degrees C with micrococcal nuclease. Three chromatin fractions were successively obtained: an isotonic extract (ne3H1), ahypotonic extract (ne2) and the residual pellet (P). The Dex-RG complexes were measured by the hydroxyapatite technique. The MMTV DNA sequences were titrated by molecular hybridization with an excess of MMTV radioactive cDNA probe. Up to 75% of the nuclear 3H Dex and the MMTV radioactive cDNA probe. Up to 75% of the nuclear 3H Dex and MMTV DNA sequences were extracted in a concentration dependent manner while only 10-15% of nucleic acids became soluble in 10% perchloric acid. The extracted 3H Dex-RG complex was found to be partly bound to soluble chromatin and partly free. The free complex displayed similar sedimentation constants (4S, 7S) and DNA binding ability to the cytosol receptor. The 3H Dex-RG complexes were 2 to 8 fold more concentrated in ne1, which is known to be enriched in active chromatin, than in ne2. Conversely, the concentration of MMTV DNA sequences per microgram DNA was the same in the three nuclear fractions. These results suggest that the Dex-RG complexes are concentrated in an active fraction of chromatin. We propose that, among the 20-30 copies of MMTV genes per haploid genome, only a small proportion are transcribed or regulated.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
After extirpation of an hind limb in embryos of Lacerta viridis, numerous motor neuroblasts degenerate on the operated side, in the ventral horn of the lumbar spinal cord and the corresponding motor column is reduced or disappears. The lumbar spinal ganglia are affected and reduced on the operated side.
In embryos of Snake-like Reptiles (Anguis fragilis) and of Ophidians (Tropidonotus, Python), the lay-out of motor neuroblast in the ventral horns of the spinal cord, in the brachial and the lumbar regions differs from the one observed in the same regions of embryos of tetrapod Reptiles (Lacerta viridis).
The diagnosis of proctated jaundice is done in 50% of all cases by clinical examination; in 30% of all cases by peritoneoscopy; in the other 20% instrumental opacification of the biliary tract is required (before the laparotomy) in order to determine the site and the nature of the cholestasis. Among these instrumental devices, a transhepatic cholangiography with the Okuda needle allows biliary tract opacification in 98% of all cases if the obstacle is extra-hepatic and in 69% of all cases if the obstacle is intra-hepatic. This technique is easy to perform, without danger, and readily available to any physician. It should be performed after the peritoneoscopy and before the retrograde cholangiography.
Explore the source record for details and available documents.
Numerous papillomata affecting the skin of the dorsal part of the body occur in a population of Lacerta viridis reared in the laboratory. Electron microscopic study of three of these growths revealed the presence of viral particles belonging, from the morphological aspect, to the groups of the viruses of Herpes, Reo and Papova.
Intracytoplasmic degeneration bodies are present early in the cells of the apical ridge of the limbbud in embryos of Testudo graeca; next, they are obvious in the apical fold till formation of the analgen of the fingers. This cell death may be responsible for a certain rudimentation of the limb (reduction of length of phalanges) in this species of Turtle.
The development of the limbs has been studied in 15 embryos of Scelotes gronovii, found in 8 ovoviviparous females collected at Saldanha Bay, in South Africa, Cape Province. This study leads to the following constatations: In all the young embryos of this species, their appears anlagen of anterior and of posterior limb-buds. The primordia of forelimb-buds retrogress early and disappear, whereas the primordia of hind limb-buds transform into rudimentary limbs which persist in adult. Histological study of the anlagen of fore limb buds establish that 7 somites (S6 to S12, S1 being the first post-otic somite) send ventral processes in the mesoblast of the anlage. These processes follow a sinuous pathway in the limb-bud, and are bent towards the basal cell layer of the somatopleural mesoderm. On the apical part of the limb-bud lie a wholly rudimentary epiblastic ridge, which disappears early. On the apical part of the hind limb-bud an ectodermic ridge is present, well differentiated which transforms soon in an apical fold; and the anlage of the hind limb produced a short conical appendage with short femur, tibia and fibula and one terminal finger. A comparison was made of the main steps of the development of the limbs in three species of Scelotes with rudimentary limbs. Scelotes inornatus, Scelotes brevipes and Scelotes gronovii. In these three species the ectodermal apical ridge of the fore limb-buds is rudimentary or incompletely differentiated; it never transforms into an ectodermal fold and its retrogresses rapidly; and in these species an early arrest of development and an involution of the primordia of the limb-buds occurs. These fact corroborate the anterior observations made on embryos of Anguis fragilis and of Ophisaurus apodus and they strengthen the interpretation postulating that the spontaneous retrogression of the apical ridge is an essential factor in the morphogenetic events involved in the arrest of development of the limb bud in the snake-like Reptiles.
Based on characteristics of mitochondria and on the amount of lipid inclusions, a distinction between somitic cells and mesoblastic somatopleural cells is possible, at the early stages of the development of the limb bud in Reptiles (Anguis fragilis and Lacerta viridis). The dislocation of the ventral processes of the somites and the localisation of the somitic cells in the mesoblast of the anterior limb buds could be studied.
Cytophotometric determinations establish that in the limb buds of young embryos of the slow worm (Anguis fragilis L.) and of the green lizard (Lacerta viridis Laur.) the level of nuclear proteins and RNA is higher in the cells of the apical crest than in the cells of the epiblast on either side of the crest. This relative increase is progressively y reduced.
Ultrastructural characteristics of the cells of the apical crest, of the mesoblast and of the ventral processes of somites, in the anlage of the anterior limb buds of embryos of the slow-worm (Anguis fragilis) and of the green lizard (Lacerta viridis) are described at early stages of the development. Differences between the two species studied are brought to light.
An electron microscopic study of the components of anterior limb buds of the slow-worm (Anguis fragilis) and of the green lizard (Lacerta viridis) (embryos of Anguis whose allantoic bud reach 0,7 to 4 mm of length; embryos of Lacerta 2 to 7 days old) provides data on the cytological characteristics of the components of the limb bud at these early stages. 1. The cells of the distal extremity of the somitic processes extending in the limb bud of Anguis and Lacerta, are elongated cells with ovoid nuclei containing large nucleolus; they possess mitochondria always thin and with dense matrix; they are rich in lipid droplets; they possess cilia; they are devoid of myofilaments; endoplasmic reticulum, free ribosomes and polyribosomes are abundant. Golgi networks display signs of activity. These characteristics are also observed in the cells of the "dermatome" layer of the dermo-myotome; and so, it appears probable that the cells of the "dermatome". Furthermore, in Anguis embryos, the cells of the distal extremities of the somitic processes possess numerous lysosomes and a certain number of cells among them, degenerate early. 2. The somatopleural mesoblastic cells of the limb bud of Anguis and Lacerta embryos keep the characters of the cells of the mesodermic layer of lateral plate from which they originate; they have rounded nuclei, cilia, and their mitochondria are always larger and more transparent to electrons, than the ones of cells of the somitic processes and of cells of the epiblastic apical crest. Golgi networks are well developped, endoplasmic reticulum is abundant, lipid droplets are rare. 3. The processes of somites which extend in the dorsal part of the limb bud of Anguis embryos are cords of cells with thin lumina; at the stage of the allantoic bud of 0,6 to 0,8 mm long, the distal extremity of these processes dislocate in group of cells which afterwards dissociate, releasing individual somitic cells which are integrated among the mesoblastic somatopleural cells. In young lizard embryos (2 to 4 days old) the distal extremity of the somitic processes enlarges into a vesicle from which cells are released and penetrate in the mesoblast of the limb bud. 4. The somitic cells released from the somitic processes of Anguis and Lacerta keep--at least at early stages--the cytological characteristics they displayed when they were still in situ in the somitic processes: grounded on the presence or absence of lipid droplets, on the width and density of the mitochondria, the distinction, at these stages, between the somitic and mesoblastic somatoplerual cells is possible; and it is also possible to observe the integration of the somitic cells into the mesoblast. This study brings the demonstration of the cellular contribution of the somites to the formation of the limb bud in Reptiles. 5...
Explore the source record for details and available documents.
Explore the source record for details and available documents.