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Biomedical subjects

M Rabaud

Publications and source records attributed to M Rabaud.

At least 73 records · Page 4Linked to original sources
PubMed1983

[Xanthine oxidase activity: NAD+-dependent and O2-dependent forms in carrageenan granuloma in the rat].

Xanthine oxidase activity: NAD+-dependent form (D) and O2-dependent form (O) were carried out in cytosol supernatants of connective tissue growth (T.C.N.F.), skin tail, liver and plasma of carrageenan induced granuloma in the Rat. The specific activities of skin, liver and plasma were normal in animals with a granuloma. The total specific activity (D + O): 7.53 +/- 0.98 mU/mg protein, and the percentage of form O: 51.6 +/- 5.1 of the granulomatous tissue as compared to the tail are significantly increased. These results suggest the likely function of xanthine oxidase during the inflammatory response.

Animals↗
PubMed1982

The human blood platelet: a cellular model to study the degradation of thymidine and its inhibition.

Intact platelets catabolize extracellular thymidine into thymine. Studies of the concentration dependent degradation of thymidine by intact platelets indicate a Michaelis mechanism with an apparent Km of about 0.12 mM and a Vmax of 2.5 nmoles/min for 3 X 10(8) platelets. This degradation process is inhibited by various nucleosides, pyrimidine bases and C-5 or C-6 substituted uracils. Cytidine, deoxycytidine, adenosine and deoxyadenosine seem to inhibit thymidine degradation by reducing the intracellular transport of thymidine. Uridine inhibits both the thymidine transport and the activity of the phosphorolytic enzyme, thymidine phosphorylase (EC 2.4.2.4). Some substituted uracils are specific inhibitors of thymidine phosphorylase activity. 6-Amino-5-bromouracil, the most active of them, either with acellular extracts or purified thymidine phosphorylase, is also the best inhibitor of thymidine degradation in intact human platelets. Platelets constitute a new model to study the efficiency of specific inhibitors on thymidine catabolism in an 'human intact cell' which contains only one pyrimidine nucleoside phosphorylase, the thymidine phosphorylase.

Biotransformation↗
PubMed1982

Adjuvant arthritis in rat during pregnancy and lactation.

We have studied, in the female rat, the influence of pregnancy, lactation and pseudo-pregnancy on adjuvant arthritis. Pregnancy has a suppressive effect on the arthritis all the more marked as arthritis onset occurs during the third part of pregnancy. Pseudo-pregnancy with or without decidualization of the uterus does not modify the arthritis course; thus the corpus luteum and the decidual tissue cannot account for the observed improvement. Lactation has a beneficial effect that lasts until weaning. Amount of estradiol which insured approximate serum level of pregnant rats improves the polyarthritis. In the same conditions, progesterone remains inactive. Suppression by estradiol is observed in ovariectomized and intact females. Thus, in the female rat, pregnancy, lactation and physiological doses of estradiol improve adjuvant arthritis.

Animals↗
PubMed1982

Comparison of effects of D. Penicillamine and dexamethasone on the articular and non articular lesions in immune connective tissue disease induced in rabbits.

The effect of D. Penicillamine (DP) at the dose of 50 mg/kg/day, on an immune induced connective tissue disease in rabbit, is compared to that of dexamethasone (Dexa) at the doses of 0.15 and 0.075 mg/kg/day. This model includes polyarthritis and lesions of connective tissue of liver, kidneys and lungs. The result of immunization is initially a non-specific macrophage infiltration and secondarily a specific lymphocyte and plasma-cell infiltration. In short treatment, high dose of Dexa inhibits the non-specific and specific responses while DP modifies only non specific response. In long treatment, Dexa at low dose and DP inhibit the two responses. Data suggest that, in vivo, macrophages is the target cell of DP.

Animals↗
PubMed1981

Catabolism of thymidine in human blood platelets: purification and properties of thymidine phosphorylase.

A pyrimidine nucleoside phosphorylase was partially purified from human blood platelets. The purified enzyme, as well as crude enzyme preparations, catalyses the phosphorolysis of thymidine and deoxyuridine, but not of uridine, and is able to catalyse direct pentosyl transfer from these deoxyribonucleosides to uracil or thymine; this enzyme has the properties of a thymidine phosphorylase. It has a molecular weight of about 110,000 and is composed of two identical subunits; it is phosphate dependent, has a maximal activity at a pH value of 5.7, and an isoelectric point of 4.4. This enzyme was mainly of cytoplasmic origin. Although platelet thymidine phosphorylase could promote the degradation or synthesis of thymidine, intact platelets degraded thymidine but were not able to synthesize thymidine from thymine. Blood platelets may play an important role in the degradation of plasma thymidine.

Blood Platelets↗
PubMed1981

A specific one step method for the isolation of pancreatic elastase; its use to characterize aortic elastase.

Elastase was purified from an acetone-ether powder of porcine pancreas by a one step affinity chromatography procedure on IgG-Sepharose 4B. The IgG was derived from a rabbit immunized with porcine pancreatic elastase and was itself isolated by affinity chromatography on elastase immobilized on the same matrix. The column was calibrated with a known elastase preparation under standardized conditions. Direct isolation of elastase from pancreatic extracts yielded approximately 90 mg from two pancreas. The enzymatic activity and electrophoretic migration in SDS-polyacrylamide gel of the purified elastase were equal to those of the purest commercially available enzymes. Application of this method to aorta of young pigs suggests the presence of active elastase in the aorta.

Animals↗
PubMed1981

[N1-substituted 1H-indazole-3-ethyl carboxylates and 1H-indazole-3-hydroxamic acids].

Sixty five new derivatives of ethyl-1H-indazole-3-carboxylate are described; they contain in N1 various aliphatic or aromatic acyl radicals. Moreover halogens or methyl groups are present as substituents at the 5 position or methyl groups at 5,6. The synthesis of seven 1H-indazole-3-hydroxamic acids, substituted at 6 and/or 5 as above, is also described. Some of the synthesized derivatives have preliminarily been tested on rats to investigate acute toxicity, possible antiarthritic effects on primary or secondary arthritis, and their action on weight gain. Some of these indazole derivatives had an antiarthritic effect at doses much lower than the toxic ones; among the compounds tested up to now, the ethyl-5-methyl-N1-p-chlorobenzoyl-1H-indazole-3-carboxylate gave the best results. Weight gain as not affected by any of the examined compounds.

Animals↗
PubMed1980

[Anti-elastase of human pancreas: preparation and biological interest].

The present paper deals with the use of a new technique in type II human pancreatic elastase studies based on the use of a reversible immune-adsorbent which provides a unique specificity. According to the type of ligand linked on activated Sepharose, the elastase or its antibody in Rabbit could be obtained, in very pure form, in a one step process. The anti-human pancreatic elastase II, which specifically inhibits the enzyme, may be used in therapy whenever the elastase-inhibitor system becomes unbalanced.

Animals↗
PubMed1980

Isolation and biological properties of a rabbit antibody to porcine pancreatic elastase and its use as ligand for elastase purification.

By affinity chromatography on porcine pancreatic elastase bound to Sepharose an anti-elastase antibody was isolated from the serum of rabbits who had been injected with porcine pancreatic elastase and fed a light cholesterol diet. The protein (molecular weight 150,000 daltons) was recovered with both a high degree of purity and intact biological properties. It specifically inhibited elastolysis by a mechanism distinct from that known elastase inhibition by alpha 1 antiprotease and alpha 2 macroglobulin. Results of this study indicate that inhibition is due to an IgG antibody to the porcine elastase. The antigen-antibody reaction appears to involve the active site of elastase. The isolated IgG in turn binds to activated Sepharose and the resulting immunoadsorbent system allows purification of pancreatic elastase by affinity chromatography.

Animals↗
PubMed1978

Serum elastase inhibitors in cardio-vascular diseases.

Serum elastase inhibiting capacity was measured in three groups: 150 control subjects, 38 hospitalized children without cardiovacular diseases and 202 hospitalized patients suffering from cardiovascular diseases. The values obtained were 53% in control adult subjects and 79% (range 45--90%) in the hospitalized patient groups. The highest levels were recorded at the acute phase of myocardial infarction. The levels of alpha 1-antitrypsin (alpha1-AT) and alpha 2-macroglobulin (alpha2-M) were determined by radial immunodiffusion technique for various levels of inhibitory power. No correlation was found between the inhibitory power levels and the alpha1-AT and alpha2-M levels. This study suggests that other proteins may intervene in the inhibition process of elastolysis.

Adolescent↗
PubMed1978

[Chemical reactivity and biological properties of a series of aminochlorambucil derivatives].

The substitution of aminochlorambucil by a methyl group increased the chemical reactivity in IV b (n = 1) and IV b (n = 2) but their cytotoxicity remained low. The immunosuppressive effect (adjuvant arthritis in Rats and tuberculin related skin reaction) was observed with IV b (n = 2). Aminochlorambucil was effective on adjuvant arthritis only and IV b (n = 1) had no activity. Aminochlorambucil, IV b (n = 1) and IV b (n = 2) were devoid of any non-specific anti-inflammatory activity.

Animals↗
PubMed1978

The failure of long term effect of cyclophosphamide on systemic immunologic connective tissue disease in rabbit.

Cyclophosphamide is given intravenously in the high dose of 12 mg/kg/day during 2 months from the beginning of immunological systemic connective tissue disease in rabbits, according to the modified Glynn's model. The effects of this alkylating drug are studied after the termination of treatment. At short term (15 days), cyclophosphamide depresses the inflammation of synovia in stimulated and non-stimulated joints, the humoral and cellular immunities, but the drug does not modify the other systemic lesions. At long term (between 1 and 6 months), these effects of cyclophosphamide disappear completely.

Animals↗
PubMed1977

[Hydroxyapatite rheumatism (multiple tendon calcification disease). II. - Microscopic study - HL-A antigen - Experimental arthritis - Pathogeny].

Optical and electron microscopic studies of the articular fluid in multiple calcification disease reveals the existence of rounded intra- and extracellular crystalline formations. These crystalline formations of calcium and phosphorus are made up of accumulations of tiny crystals shaped like fine needles 200 nm X 15-20 nm and are highly suggestive of hydroxyapatite. Crystals injected into the plantar pads of rats or the knees of rabbits induce an acute inflammatory reaction maximal at 5 hours and recovering in 24 72 hours. Hydroxyapatite crystals are swiftly dissolved in serum and more rapidly still when cells are present. Their dissolution releases calcium into the surrounding area. HLA typing of patients with multiple tendinous calcification (28 cases) or single tendinous calcification (10 cases) shows an increased frequency of HLA A2 and BW 35 in comparison with controls.

Animals↗
PubMed1976

[Prevention of experimental adjuvant polyarthritis by a gallium salt in rats].

On the basis of experiences proving inhibition of some immunological reactions with the ion gallium, we have demonstrated a protecting effect on adjuvant experimental arthritis of the Rat. Consequently, gallium and some metals of the same group should be proposed to treat human arthritis with immunological dysfunction.

Animals↗
PubMed1976

Immunofluorescence of synovial membrane multifactorial analysis of the results.

Synovial membrane taken by needle biopsy from the knee joint of 61 patients with various rheumatic diseases were studied using immunofluorescence methods. Staining techniques and their controls were detailed. Classical statistical tests and principal components multifactorial analysis of the data emphasized some differences between the pathological groups. Connective tissue diseases seemed to be characterized by plasma cells fluorescence and mixed immunoglobulins and complement deposits. These were mostly localized to extracellular spaces in sero-positive rheumatoid arthritis and to blood vessels in sero-negative rheumatoid arthritis and systemic lupus erythematosus. On the contrary, isolated immunoglobulins without complement were mostly found in the other inflammatory arthritis, while negative results were obtained in non inflammatory arthropathy. Immunoglobulin classes did not seem to have any diagnostic value. On the contrary, rheumatoid factor was specific for rheumatoid arthritis, whatever the serological pattern was, and it was particularly frequent in patients suffering from rheumatoid arthritis associated with a Sj5AOGREN SYNDROME. A strict relationship between classical histological findings and immunofluorescence results was not always found; so, immunological methods can be aquivocal.

Arthritis↗
PubMed1975

Estimation of seric and parietal inhibiting power of elastase; its changes with experimental conditions.

The existence of a parietal elastase and its physiological role in the pathology of the arterial wall remain unknown: it is probably difficult to demonstrate its specific activity because of existing tissular inhibitors, homologus to seric inhibitors. The change of seric inhibitor power when elastase is injected to animals with or without a cholesterol diet is discussed. Moreover, an aortic inhibiting power against elastase is shown. Our results emphasize some new aspects of elastase in its role in arterial wall pathology.

Animals↗