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J Hourdry

Publications and source records attributed to J Hourdry.

At least 37 records · Page 2Linked to original sources
PubMed1983

A histological and dynamic study of the gastric region of Discoglossus pictus larvae, cultured with or without thyroxine.

The organotypic culture of the gastric region is carried out on premetamorphic Discoglossus pictus larvae. Adding thyroxine to the culture medium provokes various transformations. On the cytological level, the reactions observed, which are variable depending on the cell category concerned, can be divided into two types of phenomena: histolytic and histogenetic. Autophagia linked to lysosome intervention is frequently found among the histolytic processes. Autophagic vacuoles and residual bodies are observed. The gastric lumen is filled with deteriorated cells that probably come from the degeneration of the tadpole epithelium (primary epithelium). The incorporation of tritiated thymidine makes it possible to study the evolution of cell proliferation in the control and in the thyroxinated cultures. After a 1-2 day latency period, possibly due to the adjustment of the tissue to the culture environment, the incorporation of the radioprecursor H3-thymidine into the epithelium and the tunica muscularis of thyroxine-treated gut tissue increased on day 3, reached a maximum on day 5, and then dropped slightly on day 7. In the control cultures H3-thymidine incorporation showed the same pattern but lower levels on the same days. The histolytic phenomena induced by thyroxine in vitro are comparable to those of natural metamorphosis. On the other hand, the histogenetic phenomena are incomplete. Proliferating and transitional phases occur but neoformated (or secondary) epithelium does not replace the degenerated primary epithelium, whatever the culture time.

Animals↗
PubMed1983

Development of peroxisomes in amphibians. III. Study on liver, kidney, and intestine during thyroxine-induced metamorphosis.

This investigation was undertaken to study the ontogeny of hepatic, renal, and intestinal peroxisomes and/or microperoxisomes during thyroxine-induced anuran metamorphosis. Catalase activity was localized cytochemically after incubation in DAB medium, and studied biochemically by a spectrophotometric method. Our morphological and biochemical investigations suggest the formation of a new population of peroxisomes during the hormonal treatment. This is obvious especially for microperoxisomes of the intestinal epithelium since the larval tissue is completely replaced by a new layer during thyroxine-induced metamorphosis. For the peroxisomes of hepatocytes and kidney proximal tubule cells, our assumption is based on the following observations: 1) The number of peroxisomes increases in liver and kidney during thyroxine treatment; 2) this proliferation is accompanied by an enlargement of renal peroxisomes; and 3) 16 days after the beginning of the hormonal treatment, 5.4- and 2.4-fold increases are found for the specific activities of hepatic and renal catalase, respectively. A temporal coordination exists between the structure and the metabolism of peroxisomes and mitochondria during thyroxine-induced metamorphosis.

Animals↗
PubMed1982

Development of peroxisomes in amphibians. II. Cytochemical and biochemical studies on the liver, kidney, and pancreas.

The ontogeny of catalase-containing organelles was studied by cytochemical and biochemical methods in the liver, kidney, and pancreas during the development of Rana catesbeiana. The biochemical differentiation of peroxisome in the liver and kidney was compared to that of Xenopus laevis. Catalase activity was localized after incubation in DAB medium and studied biochemically by a spectrophotometric method. In Rana Catesbeiana the number of catalase-positive organelles per cell section is low in all three organs during premetamorphosis; their number increases substantially in the liver and kidney of froglets, while it remains almost stable in the pancreas. No further increase is observed in the adult. Biochemically, the liver, kidney, and pancreas of tadpoles exhibit, respectively, 12,22 and 63% of the catalase activity found in the adult tissues. After metamorphosis an important increase of catalase activity is particularly noted in liver and kidney, the activity being, respectively, 43 and 77% of that of adult bullfrogs. On the other hand, no change in catalase activity in the liver and kidney is noted during the entire development of Xenopus laevis. The present study illustrates the very different developmental pattern of catalase activity observed during the development of two anuran amphibians. The different development pattern of the same enzyme within the small intestine, liver, kidney, and pancreas in Rana catesbeiana is also stressed.

Aging↗
PubMed1982

Aluminum phosphate visualisation of acid phosphatase activity: a biochemical and x-ray microanalysis study.

A new method is described that demonstrates acid phosphatase activity in the cells of the proximal tubules of the rat kidney. The method is based on the formation of an insoluble aluminum phosphate precipitate. Microanalysis was used to demonstrate the presence of intracellular aluminum and determine the quantity present under the probe. Parallel biochemical studies showed that the aluminum precipitate was indeed due to acid phosphatase activity.

Acid Phosphatase↗
PubMed1981

[Changes in the intestines of obstetrical toad (Alyte obstetrician) larvae during spontaneous metamorphosis or metamorphosis induced by thyroxine. Morphometric study and changes in the protein/DNA ratio].

During spontaneous metamorphosis of Alytes obstetricans tadpoles (Anuran Amphibia), the gut undergoes important modifications. The gut weight/total weight and gut length/body length decrease by stage XVIII. They reach maximum reductions of 83 and 90%, respectively, by stage XXIII. Tail regression begins only by stage XX. The intestinal protein/DNA ratio peaks to a maximum by stage XIX, decreases greatly by stage XX then increases slightly by stage XXII. During thyroxine-induced metamorphosis, the morphometric changes are observable after a lag period of 36-48 hs, prior to detectable tail reduction. The intestinal protein/DNA ratio of T4-treated tadpoles remains constant and no difference with control data is noted.

Animals↗
PubMed1980

Amphibian intestinal brush border enzymes during thyroxine-induced metamorphosis.

The development of intestinal brush border hydrolytic activities has been studied during thyroxine-induced metamorphosis of Rana catesbeiana. Alkaline phosphatase activity peaks at 3 and 10 days after the beginning of the thyroxine treatment. The cytochemical observations concerning alkaline phosphatase activity are in agreement with the biochemical data. At the ultrastructural level, alkaline phosphatase activity is particularly evident on the microvilli membranes of the enterocytes in the primary epithelium after 3 days and in the secondary epithelium after 10 days. gamma-Glutamyltranspeptidase exhibits an increase of activity between 7 and 10 days. On the other hand, glucoamylase, maltase, trehalase and leucylnapthylamidase activities decrease during thyroxine treatment, these enzymatic activities being lower than that normally observed after natural metamorphosis. The present study indicates that even though thyroxine is able to induce the morphological differentiation of the intestinal epithelium this hormone is unable to complete the enzymatic load of the new mucosa.

Alkaline Phosphatase↗
PubMed1979

Conjugated effects of thyroxine and X-rays on the intestinal wall of Alytes obstetricans larvae (Anuran Amphibian).

The conjoined effects of thyroxine and X-rays on the intestinal wall were studied using Alytes obstetricans tadpoles in premetamorphosis. Thyroxine alone induces degeneration of the larval epithelium (primary epithelium) and its replacement by a secondary epithelium. The latter is derived from stem cells via the development of islets. In animals submitted to irradiation only, many of these stem cells showed signs of necrosis. In irradiated larvae treated with thyroxine, the secondary epitheliocytes were rare and never formed islets. Radioautographic observations confirmed their very low proliferation rate. Contrary to what was observed in the hormone treated larvae, cell fragments of the primary epithelium were extruded in the connective tissue, and phagocytes appear to infiltrate the epithelium. In animals treated with thyroxine and later submitted to irradiation, islets of secondary epitheliocytes developed while some cells degenerated. There again, the phagocytes were noted in both the connective tissue and the epithelium.

Acid Phosphatase↗
PubMed1979

Ultrastructural localization of alkaline phosphatase activity in the intestine of developing Rana catesbeiana.

Alkaline phosphatase activity has been localized at the light and electron microscopic levels in the intestine of developing frog, Rana catesbeiana. The intensity of the histochemical reactivity decreases along the intestinal tract. The intracellular localization of the enzymatic activity shows continuous series of organelles loaded with the reaction product from the Golgi zones to the brush border. These results are in agreement with the biochemical observations made on the same material.

Alkaline Phosphatase↗
PubMed1979

Amphibian intestinal brush border membranes-I. Isolation from Rana catesbeiana tadpole.

1. Intestinal brush border membrane vesicles have been isolated form Rana catesbeiana tadpole. 2. Electron microscopy of brush border membrane vesicles demonstrates a fairly homogenous preparation of vesicles, some of them still containing electron dense material. 3. The dense vesicles probably comprise both microvillus core and membrane. 4. Negative staining of vesicles reveals the presence of knob-like structures (particles) covering the outer surface of the membrane. 5. The membranous fraction is characterized by a high specific activity of alkaline phosphatase, trehalase, glucoamylase, maltase and gamma-glutamyltranspeptidase.

Animals↗
PubMed1978

Chromium concentration by proximal renal tubule cells: an ultrastructural, microanalytical and cytochemical study.

After treating rats with potassium bichromate, x-ray microanalysis of the proximal renal tubule cells demonstrated the presence of chromium in intracellular vacuoles. The lysosomal nature of these vacuoles is shown by the visualization of acid phosphatase activity. Chromium is concentrated both in the autolytic vacuoles and in their residual forms. The metal is eliminated quite late, concomitant with cellular necrosis.

Acid Phosphatase↗
PubMed1977

[Determination of the relative iodine concentration in the lumens of thyroid follicles of normal and neotenic Triturus helveticus, and evaluation of the halogen content of the thyroid colloid. Electron microprobe study (author's transl)].

The stable, bound iodine in the thyroid colloid of Triturus helveticus has been studied with the electron microprobe. Some animals show a normal development. Others are accidentally neotenic due to certain ecological conditions. The values of punctate iodine concentrations (CPI) have been computed and expressed in relative units (counts/s). The mean CPI per lumen is very variable from one follicle to another in the same thyroid section. During normal development, the mean CPI per animal is generally higher in metamorphosing individuals than in larvae. During development with neoteny, the mean CPI per animal attains high values if the larval state is maintained in its totality; the CPI decreases in partially metamorphosed animals, but increases again after metamorphosis. The amount of halogen contained in the thyroid colloid has been computed in relative units (colloid iodine pool). Throughout normal development, the pool remains small if the animals have not attained the adult state. In increases considerably in entirely larval neotenic newts, decreases during metamorphosis but increases afterwards. In totally neotenic newts, the thyroid gland receives only a low hypophyseal stimulation and reacts as the thyroid gland of various hypophysectomized Urodeles. Our results pose the problem as to whether TSH regulates the transepithelial iodine flows, which permit the expansion of the colloid iodine pool, when this hormone is secreted at a very low levels.

Animals↗
PubMed1976

Aluminium localization in amphibian skin with the electron microprobe and ion microanalyzer.

EMP and IMA studies show the presence of A1 in the epidermis of larvae and young adults of Discoglossus pictus and Rana esculenta, which disappears during later stages of development. A1 is practically absent in the epidermis of Xenopus laevis and Pleurodeles waltlii. The localization of A1 with EMP and IMA supports the biochemical results. The function of A1 in the epidermis is not known at present.

Aluminum↗
PubMed1976

[Electrophoretic analysis of intestinal acid phosphatase and N-acetyl-beta-glucosaminidase in the Discoglossus tadpole treated by thyroxine].

Polyacrylamide gel electrophoresis has been used to separate the two isoenzymes of intestional acid phosphatase (PI and P2) and N-acetyl-beta-glucosaminidase (G1 and G2) in Discoglossus pictus tadpoles treated by thyroxine. When the isoenzyme activities of each pair are expressed as percentages, the activity of the slower form (P2 or G2) increases significantly when the tadpoles are treated by the hormone.

Acetylglucosaminidase↗
PubMed1975

[Metabolism of radioiodine in Xenopus thyroid during larval life and metamorphosis].

Radioiodine uptake and metabolism study show variations in the functional state of thyroid glands of Xenopus through larval development. During metamorphic climax, the level of hormone synthesis is the highest ; after metamorphosis, labeled thyroid hormones proportion decreases significantly. Normal metamorphosis sequences depend on the gland functional state changes.

Animals↗