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J Renais

Publications and source records attributed to J Renais.

53 records · Page 3Linked to original sources
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Cartilage and bone formation in arterial wall. 1. Morphological and histochemical aspects.

Cartilaginous and/or osseous foci were observed in eight aortas from 20 rabbits immunized against heterologous aorta homogenates and sacrificed 11 to 24 months later. They were studied by means of histological and histochemical methods and compared with normal aortas, cartilage and bone. Some of the observed changes seemed to be true markers of these transformations. Chondroid metaplasia was characterized by 1) generalized increase in alcianophilic hyaluronidase sensitive substances. 2) Appearance of Dermatan and/or Keratan sulfates round some isolated cells. 3) Advent of G6 Pase and Alk. Phase activities in cells adjacent to osseous foci. Osteous metaplasia was characterized by 1) decrease, then disappearance of alcianophilic and PAS positive material, 2) increase in osteoblastic alkaline Pase-activities.

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Cartilage and bone formation in arterial wall. 2. Ultrastructural patterns.

The ultrastructural aspects of cartilaginous and osseous foci developed in aorta of rabbits immunized against rat aorta homogenates was studied. Besides normal and modified smooth muscle cells, various types of transformed mediacytes were observed in and around these foci: some of them resembled connective and young mesenchymatous cells, others had the appearances of cartilaginous and osseous cells. The possible role of the modified (multipotential) smooth muscle cells in aortic chondro- and osteogenesis is considered in some cases. Following histogenetic pathway is suggested: s.m.c. leads to modified s.m.c. lead to young mesenchyme-like cells ("inducible osteogenic precursor cells") leads to "chondro-mediacytes", "osteomediacyte".

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[Aortic development and ageing in the rat aorta -- Comparative histochemical and histoenzymological study (author's transl)].

A comparative study was made of 36 aortic enzyme activities (E.A.) and 6 macromelecular substances at different stages of ontogenesis in 49 male rats. In the foetal aorta (19th day) the E.Z. were moderate or weak and restricted to a few metabolic pathways: glycolysis, diaphorases, esterolysis of some nucleotides and glucosaminoglycan (GAG) metabolism. During the neonatal period (1st-3rd day), the pre-existing E.A. increased; some aerobic and lipolytic activities became histochemically detectable; longitudinal and radial gradients became established. These changes seemed to provide evidence of increased morphogenic activities and metabolic exchanges. During the prepuberty and puberty period (10-20th day-2nd month) all the E.A., as well as metachromasis and pyroniophilia increased, and new E.A. appeared (GluDH, GPDH, 5/Nase, Ac.Pase-Ca++, Mg++, pH 7.2). These changes appeared to be related to cell proliferation and connective tissue increase during the period of fast aortic growth. The increase of some E.A. (Est/ase, Ch. est, ATPase-Ca++, Mg++, 5/Nase, Alk. Pase) suggested a correlation between enzymatic differentiation and hormonal maturation. During adulthood (6-12th month), the E.A. were stable except for 5/Nase, lysosomal and lipolytic activities which increased. Some E.A. were found to be high (diaphorases, glycolytic and esterolytic enzymes), or moderate (aerobic oxidoreductases, lysosome, lipolysis and GAG-linked E.A.), while others were weak or absent (glycogen pathway E.A.). These observations seemed to correlate with synthetic processes and defence mechanisms. Ageing (17th month) was characterized by an increase of metachromatic GAG and acid lipids and by a decrease of pyroninophillia. Lysosome, glycolysis and phospholipogenesis-linked E.A. increased. In some animals (individual reactivity) kreb's cycle and lypolysis-E.A. decreased.

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In vitro immune aggression against rabbit aortic smooth muscle cells.

Rabbit aortic smooth muscle cells cultivated with certain antisera underwent growth changes and necrosis. These cytotoxic antisera were obtained by immunizing rabbits against rat aorta, human or pig aortic glycoproteins, human serum glycoproteins and E. coli lipopolysaccharide. These different antigens share some biochemical characteristics, and contain four main amino acid residues (Glu, Ala, Asp, Gly) and four sugars (mannose, galactose, glucose, N-acetyl glucosamine). The cytolytic properties of these antisera, however, probably correspond to structural analogies, since although ovalbumin is a glycoprotein, anti-ovalbumin antiserum was not cytotoxic. Antibody cytotoxicity against rabbit arterial smooth muscle cells may depend on the biochemical structure of the antigen used to produce antiserum.

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[Aortic myocytes and calciferol-induced arterial calcification: ultrastructural and biochemical study].

Thirty0seven rats were given Vitamin D2 orally at the daily dose of 4000 I.U. for two months, then 8000 I.U. for the following two months and 26 rats were used as controls. Batches of both intoxicated and control rats were sacrificed on the 15, 30, 45, 90 and 120 days after the onset of the experiment. This chronic calciferol intoxication allowed a better understanding of the calcifying process. Modified myocytes were observed early and for a long time in and around the mineralizing foci. They had the ultrastructural and histochemical characteristics of cells with an activated metabolism: excessive development of the organelles linked with synthesis processes, hyperactivity of phoshatases, of lysosomic enzymes and of enzymatic systems of cell respiration and glycolysis. Some data of the present study support the hypothesis that myocytes may be a local factor for the aortic calcification process: by increasing the conjonctive constituents calciphily, by producing phosphate and sulphate anions as well as calcifiable organic materials (glycoproteins, GAG), by modification in their own environmental physico-chemical conditions favorous to calcium precipitation (acidosis, phosphate and sulphate anions supersaturation).

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[Behaviour of the aortic lipoidosis in rats twenty months after stopping of an hyperlipidic diet (author's transl)].

48 rats were placed on an hyperlipidic diet (cholesterol, cholic acid, cholin, propylthiouracil), 23 were sacrificed at various intervals from the fourth up to the twelve month of the experiment. In the remaining 25 rats, the atherogenic regimen was replaced by a normal one. These animals were sacrificed one to twenty months after stopping of the experimental diet. Aortae of experimental and control animals were studied by means of histological and histochemical technics. All the animals developed hypercholesterolemia together with intima and media lipoidosis. None demonstrated any aortic cell proliferation. The only metabolic change of the smooth muscle cell was a progressive decrease in 5' nucleotidase, acid esterase and cholinesterase activities. The return to a normal diet involved the reversion of the serum cholesterol level to normal values and the disappearance of intima lipoidosis. The reduced enzymatic activities in the media returned to normal levels around the sixth month. The surfaces of the extracellular sudanophilic areas decreased. However, twenty months after stopping of the atherogenic diet, some lipids still persisted at the edges of the elastic fibres.

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