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Biomedical subjects

E Didier

Publications and source records attributed to E Didier.

12 recordsLinked to original sources
PubMed1990

Expression and distribution of carbohydrate sequences in chick germ cells: a comparative study with lectins and the NC-1/HNK-1 monoclonal antibody.

The expression of end-chain sugar residues and of oligosaccharidic sequences has been investigated in chick germ cells at critical stages during the migration, proliferation and sexual differentiation of these cells. Fluorescent lectins and indirect immunofluorescence studies using the NC-1/HNK-1 monoclonal antibody indicate a remarkable control of glycosylation during germ cell embryonal life. Besides a retained expression of glucose/mannose residues, it was found that alpha- and beta-galactose residues, N-acetyllactosamine and N-N' diacetylchitobiose sequences as well as the sulfated trisaccharidic NC-1 epitope were detectable in a stage-specific pattern. Present at a very high density in the cytoplasm and on the surface of the early germ cells at premigrative and migratory stages, the staining for these carbohydrate sequences gradually disappeared when the germ cells settled and proliferated in the developing gonadal primordia. The disaccharide Gal beta 1----3 Gal NAc was exclusively detected in migrating PGCs. In sexualized gonads, acetyllactosamine and/or diacetylchitobiose were similarly reexpressed in both oogonia and spermatogonia. Spermatogonia displayed beta-galactose residues and a high immunoreactivity with the NC1 Mab, indicating modulations in PGC glycosylations related to the acquisition of sexual phenotypes. In addition NC-1 was found to be expressed in the somatic component of the undifferentiated gonad and in the testis interstitial gland.

Animals↗
PubMed1988

Effects of pantothenic acid on fibroblastic cell cultures.

To evaluate the effects of pantothenic acid during wound healing processes, fibroblastic cell cultures originating from foreskin were established and subcultured by trypsinization. PA (40 micrograms/ml) was added to the basal culture medium. The cell proliferation was estimated by cell count and determination of 3H-thymidine incorporation. The protein synthesis and secretion were determined by dosage in the cells and in the culture medium. When PA was added to the medium, a significant increase of cell proliferation and of 3H-thymidine incorporation was observed mainly during the first few days. PA also stimulated intracellular protein synthesis, but did not induce a release of proteins in the culture medium. The exact mechanism involved in this phenomenon remains unclear at this time.

Cell Division↗
PubMed1988

Lectin activity and distribution of chicken lactose lectin I in the extracellular matrix of the chick developing kidney.

A lectin activity inhibitable by thiodigalactose, N-acetyllactosamine, lactulose, lactose and by an antibody raised against CLL I (chicken-lactose lectin I) has been investigated in the chick embryo developing kidney. At post-induction stages this activity was found in both mesonephros and metanephros. In immunofluorescence and immunoelectron microscopy, the extracellular distribution of CLL I was similar in the mesonephros and the metanephros. The lectin was never found intracellularly; cultured kidney cells did not express any endogenous lectin but were rich in lectin-receptor sites, which led to the hyphothesis that CLL I is not produced in situ but could be adsorbed on renal cells. Potential physiological roles for embryonic lectins are discussed.

Animals↗
PubMed1988

Role of pantothenic and ascorbic acid in wound healing processes: in vitro study on fibroblasts.

In order to analyze the possible role of pantothenic acid (PA) and ascorbic acid (AA) in wound healing processes, the effects of these vitamins upon the growth of fibroblasts, obtained from human fetal skin or foreskin, were studied. Cell proliferation, protein synthesis and protein release were evaluated. The rate of cell growth remained identical when PA or AA were added to the culture medium. PA increased the basal incorporation of 14C proline into precipitated material while AA did not modify this action. However, when cultures were incubated with PA and AA, the release of intracellular protein into the culture medium increased. These results suggest that the combined use of these two vitamins might be of interest in postsurgical therapy and in wound healing.

Ascorbic Acid↗
PubMed1977

[Establishing of an asymmetry index in the germ cell distribution between the genital ridges in the Hubbard chick embryo].

Germ cell numberings inside the gonadic anlages of Hubbard chick embryos allowed us to display these following events: From stage 23 to stage 26, the germ cell number obviously increases. It is for this period that an asymmetry index number, specific for the Hubbard strain is got, thanks to a decreasing in the number of gonocytes colonizing the right gonad epithelium. It is for the same period that the medulla differentiates and becomes populated with gonocytes. Such simultaneous events allow us to suppose that the gonadic colonization might result from some interactions between the germinal epithelium and the underlying mesenchyme.

Animals↗
PubMed1976

[Germinal population of gonads in some chimerical embryos obtained by connecting pieces of japanese quail and domestic chick blastoderms (author's transl)].

The experimental realization of chemerical embryos (Martin's13 technic) permits a quantitative appreciation of the modalities of the colonization of quail gonads by chick germ cells. Results clearly show that nature and origin of the somatic part of the gonad areas settle the characters of the genital ridges populating, and specially the specific index of asymmetry expressed by the percentage of PGC colonizing the right gonad.

Animals↗
PubMed1976

[Quantitative aspects of the colonization of the gonads by germ cells in the quail embryo (Coturnix coturnix japonical)].

A quantitative analysis made on quail embryos coming from 13 isolated parent-couples reveals some significative variations of a genetic origin, between some of the offspring studied: the differences observed concern both the quantitative importance of the colonization of gonads by germ cells and the asymmetrical distribution of PGGs (primordial germ cells) between the two genital ridges. The chronological study of the colonization in the quail shows, as in both the duck and the chick, two periods of rapid and regular increase of the number of gonadic PGC, at stages from 13 to 18 and from 24 to 30 of Hamburger & Hamilton. The distribution of germ cells between the two genital ridges is, at the beginning of the colonization, not very asymmetrical. Between stages 18 and 24 the asymmetry increases and remains stable so that the mean value of D% (percentage of the number of PGC contained in the right gonad) from that moment on is equal to 29-34%. This value is specific for the quail embryo.

Animals↗