Search PubMed⌕ Search

Biomedical subjects

M Rabaud

Publications and source records attributed to M Rabaud.

At least 37 records · Page 2Linked to original sources
PubMed1992

Oxidized alpha 1-proteinase inhibitor: a fast-acting inhibitor of human pancreatic elastase.

Unlike human neutrophil elastase or porcine and rat pancreatic elastases, human pancreatic elastase is rapidly inhibited by oxidized alpha 1-proteinase inhibitor. The second-order association-rate constant for the reaction of the oxidized inhibitor with this enzyme (kass = 10(5) M-1 s-1) is only 8-fold lower than that measured with native alpha 1-proteinase inhibitor. Elastase releases faster from its complex with the oxidized inhibitor (t1/2 approximately 0.7 days) than from its complex with the native inhibitor (t1/2 approximately 5 days). Oxidized alpha 1-proteinase inhibitor is as efficient as the native inhibitor in inhibiting the elastolytic activity of elastase. Oxidized alpha 1-proteinase inhibitor may thus be considered as a physiological inhibitor of human pancreatic elastase which may prevent degradation of blood vessel elastin during acute hemorrhagic pancreatis.

Humans↗
PubMed1992

New artificial connective matrix-like structure made of elastin solubilized peptides and collagens: elaboration, biochemical and structural properties.

Several improvements of the basic reaction between elastin peptides and type III collagen, specially the addition of heparan sulphate proteoglycans, are presented. The consequent elaboration of either cell culture support or membranes are described and illustrated by scanning electron microscopy. The material produced possesses composition, very well organized lamellar structure and some properties quite close to natural membranes such as subendothelial tissue.

Biocompatible Materials↗
PubMed1992

New artificial connective matrix-like structure: thrombogenicity and use as endothelial cell culture support.

The recently described artificial connective matrix made of elastin solubilized peptides, type I+III collagens and connective proteins is shown to have structural and biological properties very close to the natural arterial subendothelium: the capacity to promote endothelial cell cultures maintaining their phenotype expression and its non-thrombogenicity. This new bioactive composite material could be used to replace arteries.

Biocompatible Materials↗
PubMed1992

A new biodegradable elastin-fibrin material; its use in urological, digestive and cardiovascular surgery.

A new original artificial connective matrix mainly made of elastin and fibrin-like product is used to reinforce damaged tissues and to close and restore a loss of substance in several domains of surgery: all sites in the digestive system and urinary tract; besides, it can substitute for the pericardium in iterative heart operations. In all cases, the original tissue is restored ad integrum while the biodegradable material disappears completely, without any complications.

Animals↗
PubMed1992

[Substitution for an experimental duodenal substance loss in the dog with an original bioreactive material].

The aim of this study was to evaluate the suitability of the Elastin Fibrin material as a patch to close a full thickness 1.5 cm diamater duodenal wall defect in the dog. This material originates from a reaction between elastin and fibrin monomers and is available in sheet form of differing thickness. Three Beagles underwent surgical creation of a duodenal defect ant the patch closure with elastin fibrin. Coelioscopic check of the patch was performed at day 8, 15, 39, 60, 90, 120. There was no morbidity or mortality. Macroscopic and histologic examination showed complete disappearance of the patch material and restitution of the duodenal wall at 6 months. These results suggest that in selected cases, evaluation in human may be justified.

Animals↗
PubMed1991

In vitro studies of elastin-fibrin biomaterial degradation: preservative effects of protease inhibitors and antibiotics.

The degradability of a new elastin-fibrin material was tested in vitro versus human pancreatic elastase (HPE) and plasmin (PL) activities. It is shown that aprotinine Iniprol, a well-known protease inhibitor and Eglin C, a new potent inhibitor of HPE, especially when used in synergy, efficiently protected the material. A small amount of specific antibiotics was incorporated into the material. The two products will allow the material to be used in digestive surgery with improved safety.

Adsorption↗
PubMed1991

In vitro association of type III collagen with elastin and with its solubilized peptides.

Elastin fibres or elastin solubilized peptides associated with type III collagen, under physiological conditions, to form a gel-like substance. The gel cohesion could be markedly improved either by desiccation process (gently air-dried rather than lyophilized) or by addition of adhesive connective proteins such as fibronectin, laminin and type IV collagen. They conferred to the material the composition and the structural appearance of typical basement membrane-like structure. Their properties enable us to investigate the biomaterial in several domains.

Adhesiveness↗
PubMed1990

Kinetics of the inhibition of human pancreatic elastase by recombinant eglin c. Influence of elastin.

Recombinant eglin c is a potent reversible inhibitor of human pancreatic elastase. At pH 7.4 and 25 degrees C, kass. = 7.3 x 10(5) M-1.s-1, kdiss. = 2.7 x 10(-4) s-1 and Ki = 3.7 x 10(-10) M. Stopped-flow kinetic indicate that the formation of the stable enzyme-inhibitor complex is not preceded by a fast pre-equilibrium complex or that the latter has a dissociation constant greater than 0.3 microM. The elastase-eglin c complex is much less stable at pH 5.0 and 25 degrees C, where kdiss. = 1.1 x 10(-2) s-1 and Ki = 7.3 x 10(-8) M. At pH 7.4 the activation energy for kass. is 43.9 kJ.mol-1 (10.5 kcal.mol-1). The kass. increases between pH 5.0 and 8.0 and remains essentially constant up to pH 9.0. This pH-dependence could not be described by a simple ionization curve. Both alpha 2-macroglobulin and alpha 1-proteinase inhibitor are able to dissociate the elastase-eglin c complex, as evidenced by measurement of the enzymic activity of alpha 2-macroglobulin-bound elastase or by polyacrylamide-gel electrophoresis of mixtures of alpha 1-proteinase inhibitor and elastase-eglin c complex. The rough estimate of kdiss. obtained with the alpha 2-macroglobulin dissociation experiment (1.6 x 10(-4) s-1) was of the same order of magnitude as the constant measured with the progress curve method. Eglin c strongly inhibits the solubilization of human aorta elastin by human pancreatic elastase. The extent of inhibition is the same whether elastase is added to a suspension of elastin and eglin c or whether elastase is preincubated with elastin for 3 min before addition of eglin c. However, the efficiency of the inhibitor sharply decreases if elastase is reacted with elastin for more prolonged periods.

Elastin↗
PubMed1990

Biocompatibility of elastin-fibrin material in the rat.

Biocompatibility and biodegradability of a new elastin-fibrin material were investigated in several organs and tissues of the rat. It has been demonstrated that the material was quite well tolerated in all cases, except in bone marrow. Its use is considered in several aspects of reparative or constructive surgery.

Animals↗
PubMed1989

Repair of experimental arteriotomy in rabbit aorta using a new resorbable elastin-fibrin biomaterial.

A new artificial connective matrix which results from two reactions of fibrinogen and fibronectin on elastin was used to obturate a slit made in the abdominal aorta of rabbit. The so-called Elastin-Fibrin biomaterial behaved as a scaffold through which all the different structures were restored to their former condition. At 3 months, the material had disappeared and no thrombus, no inflammation or reject had been detected.

Animals↗
PubMed1989

Some factors affecting properties of elastin-fibrin biomaterial.

The elasticity, mechanical strength and permeability of a new biomaterial made of elastin and fibrin were investigated. It was shown that gamma-irradiation to sterilize the product, and sulphur derivatives (Merceptyl, thiourea, cystein) working as reticulating agents modified these properties. Depending on whether or not the biomaterial needs to be stiff, strong or elastic both physical processes could intervene separately or together. The good permeability of this material allows it to be used in several surgical fields as a true artificial connective matrix.

Biocompatible Materials↗
PubMed1988

Biochemical study of adduct synthesis between fibrin monomers and elastin.

Monomers of fibrin generated by thrombin from fibrinogen reacted with elastin to give a new addition product or adduct. Adduct formation resulted from a covalent bond between fibrin monomers and elastin. The kinetic studies of this reaction confirmed that the adduct was formed before fibrin precipitated to produce the clot. The reaction depended on elastin, fibrinogen and thrombin concentrations. When thrombin-induced and reptilase-induced fibrin were compared, it became obvious that fibrin monomers did intervene more commonly as Des AA-fibrin than as Des AA.BB-fibrin. The adduct synthesis was completely inhibited by 150 microM of the peptide Gly-Pro-Arg-Pro which was previously known to stabilize the fibrin monomers and consequently to inhibit the polymerization completely. It is shown that FXIII could intervene directly in the reaction where homological quality of elastin (human versus bovine) and purity of thrombin were other important factors.

Animals↗