Biomedical subjects

R Didier

Publications and source records attributed to R Didier.

14 recordsLinked to original sources

PubMed1992

A radioautographic study of [3H]-A 23187 (calcimycin) in components of the brain. Distribution in different cell types of the diencephalo-mesencephalic roof.

The distribution of the ionophore [3H]-A 23187 was examined by means of light and electron microscopy in elements of the central nervous system located in the diencephalo-mesencephalic roof. A 23187 is not evenly distributed in the components studied (ependyma, secretory ependyma of the subcommissural organ and neurons of the mesencephalon). At the cellular level, A 23187 appears preferentially associated with the cytoplasmic membrane as well as with the internal membranous system.

Animals↗

PubMed1992

Monoclonal antibodies as probes for the analysis of the secretory ependymal differentiation in the subcommissural organ of the chick embryo.

Monoclonal antibodies directed against components of the subcommissural organ (SCO) of the chick embryo were produced by immunizing mice with SCO homogenate. In three series of production, 788 hybridomas were screened by immunofluorescence microscopy. Four hybridoma cell lines producing antibodies that specifically recognize both SCO cells and Reissner's fiber (RF) were selected and cloned. Using these immunological probes, the ontogenetic development of the SCO and RF was investigated in the chick embryo. Immunoreactive material could be detected in the SCO anlage from stage 17 on and RF was first observed in the central canal of the thoracal part of the spinal cord in 10-day-old embryos. Monoclonal antibodies can be useful as markers for analyzing molecular mechanisms involved in the specific function of these ependymal cells.

Animals↗

PubMed1989

Detection of sex-specific proteins in chick embryo gonads and mesonephros: effects of estradiol benzoate or tamoxifen on their expression.

Gonadal and mesonephric protein patterns from 19 day old normal chick embryos were investigated by two-dimensional polyacrylamide gel electrophoresis. Under these conditions, several sex-specific polypeptides were detected. As concerns gonadal extracts, four sex-specific polypeptides, all restricted to the cytosol, were present in the testis, whereas three sex-specific polypeptides, two localized in the cytosol, the other being membrane-bound, were identified in the ovary. Among the ovary-specific polypeptides two proved to be estrogen-dependent. They appeared in the left testis of embryos after early estradiol benzoate treatment and their expression was reduced in the ovary after early exposure to the antiestrogen, tamoxifen. Mesonephros extracts of both sexes also differed in their protein composition since three additional polypeptides (one in both the cytosolic and membrane fractions, the others in the cytosol) not found in females were found to be present in males. None appeared to be affected after either estradiol or tamoxifen treatment.

Animals↗

PubMed1984

Magnesium deficiency in the Japanese quail.

Morphological effects of magnesium deficiency on liver cells and general aspects of its influence on the metabolism were investigated in young quails. Magnesium deficiency was characterized by a depressed growth, a high mortality rate, a decrease in hematocrit and magnesium and calcium plasma concentrations. Magnesium deficiency reduced the magnesium concentration in heart by 44%, but did not affect the concentration in liver. Ultrastructural aspect of liver parenchymal cells revealed that the number of mitochondria per cell section was decreased and the average area of a mitochondrion was greater in deficient quails than in control animals. The significance of these morphological changes was discussed in relation to disturbances in energy metabolism of these organelles. From these results, japanese quail appeared as an interesting experimental model for studies on metabolic disturbances in magnesium deficiency.

Animals↗

PubMed1983

Changes in glucose and lipid metabolism in starved or starved-refed Japanese quail (coturnix coturnix japonica) in relation to fine structure of liver cells.

1. Metabolic response of adult quail to fasting or refeeding was studied by measuring the main blood and hepatic metabolites. Moreover, the fine structure of hepatocytes in these physiological conditions was described. 2. Starvation or refeeding did not affect glycemia in male as in female quails. 3. Fasting had no effect on plasma free fatty acids in female quails, whereas plasma triglycerides were markedly decreased. 4. In fasted quails, there was an active ketogenesis with a high 3-hydroxybutyrate/acetoacetate ratio. 5. Ultrastructural aspect of liver parenchymal cells from fasted quails revealed alterations in the quantity of glycogen, smooth endoplasmic reticulum, lysosomes and in the form of the rough endoplasmic reticulum. 6. The significance of these morphological changes was discussed in relation to an hormonal stimulation.

Animals↗

PubMed1983

[Hepatotoxicity of 2,4,5-trichlorophenoxyacetic acid. Cytologic and biochemical study in quail embryos].

The effects of 2,4,5-T on the hepatic cell in the 13 day old quail embryo have been studied. When injected at the dose level of 80 or 240 mg/kg into non-incubated eggs, this herbicide induces a proliferation of the smooth endoplasmic reticulum. The ergastoplasmic cisternae are dilated and feature a decrease in ribosomic covering. The mitochondria are swollen showing a pale matrix and a deficiency in cristae. One also observes an increase in the amount and size of lipidic inclusions and a dilatation of bile canaliculi. Moreover, biochemical analysis reveals a significant decrease in the glycogen content indicating that 2,4,5-T disturbs the glycogenic function of the liver.

2,4,5-Trichlorophenoxyacetic Acid↗

PubMed1982

[Toxicity and certain physiopathologic effects of 2,4,5-trichlorophenoxyacetic acid, an organo-chlorine herbicide, in the adult domestic quail (Coturnix coturnix japonica)].

The effects of 2,4,5-T on adult japanese quail have been studied. The herbicide was administered daily in oral dosages at level of 100 mg/kg per day for two weeks (five days a week). In these experimental conditions, this compound was moderately toxic, the rate of mortality was low. However, we noticed a significant reduction in food consumption, body weight and egg production. The physiological disturbances resulting from the toxicological treatment are reversible.

2,4,5-Trichlorophenoxyacetic Acid↗

PubMed1977

[The toxic effects of 2,4,5-trichlorophenoxyacetic acid on the quail].

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2,4,5-Trichlorophenoxyacetic Acid↗

PubMed1975

[Study of the germ cell migration to the gonad buds of quail embryo after the action of 2,4,5-trichlorophenoxyacetic acid].

At stages 16 and 18, the germ cells counts, in the quail embryos' gonads from control and 2,4,5-T treated eggs, show no significative difference. On the contrary, at stage 20, the gonocyte numbers of the treated embryos are strongly decreased. Actually, this mechanism cannot be stage precisely.

2,4,5-Trichlorophenoxyacetic Acid↗

PubMed1972