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R Bénichoux

Publications and source records attributed to R Bénichoux.

13 recordsLinked to original sources
PubMed1987

[Progressive complications associated with polyester arterial prostheses. Study of 61 specimens following surgical excision].

Reports of individual surgical cases tend to be anecdotal because of the unique circumstances surrounding the patient, the surgeon, the intervention and, where applicable, the prosthetic device. To overcome this limitation the authors have taken a wider collaborative approach and report the analysis of 61 explanted polyester arterial prostheses associated with delayed complications on 53 patients reoperated upon in six different French hospitals. One advantage of such an independent and centralized retrieval programme is that the impact of centre specific factors, such as patient selection and surgical techniques, is minimized. Consequently, by following a standardized protocol for the evaluation of the morphologic, pathologic and mineralogic characteristics of the tissue surrounding the excised grafts, as well as the textile structure of the prostheses themselves, it has been possible to distinguish between iatrogenic and disease related complications and to demonstrate a number of general findings associated with the clinical performance of polyester arterial prostheses. Complications such as thromboses, infections and false aneurysms appear to occur randomly after different lengths of implantation, thicker fibrous tissue capsules are associated with velour grafts with highly textured yarns, the incidence of mineralized tissue and of endothelialized luminal surfaces is rare, weft knitted textile prostheses appear less mechanically stable and more sensitive to iatrogenic trauma than warp knitted, and the incidences of lipid and cholesterol adsorption, bacterial colonization and sterile fluid loss need further investigation. These observations lead to the recommendation that for patients with longer life expectancies surgeons should consider selecting low porosity, woven or warped knitted prostheses which contain yarns that have not been highly textured.

Adult↗
PubMed1986

Gastric stress ulcer of the rat: relative contribution of the pyloric sphincter, HCO3- bile reflux and mucosal blood flow.

Gastric ulceration has been induced after stress, combining 24 h of fasting and 48 h of restraint in 9 groups of 20 rats with or without a pyloroplasty or a pylorojejunostomy combined with atropine and gastric infusion of NaHCO3 or taurocholic acid. After death or sacrifice at 48 h, ulcer index and blood in the jejunum were determined. Gastric mucosal blood flow was measured semi-continuously by a laser Doppler velocimeter. There were 45% deaths after 48 h of restraint alone, and 70% in the group combining pylorojejunostomy with taurocholic acid. Mortality was lower (p less than or equal to 0.01) pylorojejunostomy alone and more significantly so (p less than or equal to 0.001) when associated with NaHCO3. There was no death when NaHCO3 and atropine were combined with restraint. The mucosal blood flow increased significantly during the first 12 h of restraint in the taurocholic acid group. Both groups with NaHCO3 had mucosal blood flows similar to the controls. Gastric acid and gastric emptying, mucosal ischemia and bile reflux are joint factors inducing gastric stress ulcer. The 100% survival and the low ulcer index after a treatment by atropine and gastric infusion of NaHCO3 suggest that these well-known drugs should be used more frequently.

Animals↗
PubMed1986

Chemically fixed human umbilical cord vein grafts as arterial substitutes: potential and limits.

In spite of reported successes, synthetic fabric grafts and microporous and plain synthetic conduits have proven unsuitable for aorto-coronary bypasses and showed weaknesses below the knee. Readily available and uniform diameter vascular substitutes with biological and mechanical properties comparable to human vessels would be of paramount interest. Following reported successes with chemically fixed human umbilical veins (HUV), we have attempted to develop smaller diameter blood conduits and have improved the currently prevalent techniques of fixation, preparation and storage to generate more convenient surgical products. In vitro assessment of the processed HUV demonstrated that the HUV can be easily processed to make an arterial substitute that can be preserved either in a liquid medium or as a dry product. However, the in vivo implantations in dogs led to disappointing results for liquid-preserved or albuminated veins. Critical-point dried grafts gave better results, unfortunately they do not heal and they can only degrade after implantation.

Animals↗
PubMed1982

New alternatives in the preparation of chemically fixed human umbilical veins as arterial substitutes.

Following reports of the successful use of chemically processed human umbilical veins as medium and small diameter arterial substitutes, the development of new and improved techniques for the preparation, fixation and storage of these bioprostheses has been attempted. A series of physical and "in vitro" tests was undertaken to predict the "in vivo" performance of these devices. The results indicate that the new techniques are not only technically feasible but may provide a more convenient, versatile and effective surgical product.

Arteries↗
PubMed1980

Processes human umbilical veins as arterial substitutes--evaluation in canine models.

Human umbilical cord vein segments have been used as vessel substitutes for damaged or occluded arteries, as aorto-coronary by-passes and as arterio-venous fistulae for dialysis. The Dardik-Biograft fixed with glutaraldehyde and the Mindich-Bioflow, fixed with ethanol and dialdehyde starch, are commercially available. They were implanted in dogs as replacements for a segment of the abdominal aorta. Post-implantation status was followed by angiography. They were evaluated after removal from sacrificed animals with the aid of scanning electron microscopy and histological techniques. Attention was focused on vessel patency, dimensional stability, integrity of the anastomosis line, lumen wall microstructure, evidence of suture damage and thrombus deposition pattern. Both types of grafts gave functional by-passes for at least until 6 months post-implantation. The Dardik-Biograft appeared more prone to thrombus formation near the anastomosis. Sparse cellular development was also noted. The Mindich-Bioflow gave rise to a prosthesis of superior thromboresistance which was more subject to mechanical damage.

Animals↗
PubMed1975

[Effects of Tham, isoprenaline and propranolol on the blood flow and vascular resistance of the liver after clamping of the afferent and efferent vessels. Relation to splanchnic shock].

To determine the roles of portal circulation and the hepatic arteries during states of shock, the authors studied on 38 dogs, the effects of 30 minutes clamping of the sub-diaphragmatic part of the inferior vena cava, the portal vein and the hepatic artery, either together or successively. They measured the pressure in these various vessels, the transhepatic flow, using Xenon133, and calculated the intra-hepatic resistance. The animals were then treated with Tham, isoprenaline and propanolol. Tolerance to clamping was improved significantly when the animals were treated with the association of these drugs. The portal pressure and the systemic arterial pressure, rapidly returned to normal. This was also the case with hepatic, venous or arterial blood flow. There was a remarkable stability between the sinusoidal and biliary resistances, compared with disturbances in control groups. The already well known beneficial effect of Tham was increased by the apparently paradoxical association of isoprenaline and propranolol. In fact, with this dosage, they counter-balanced their reciprocal disadvantages. Finally, a study of blood flow and vascular resistance in the liver, suggests the existence of two components in splanchnic shock, hepatic and visceral.

Animals↗
PubMedDate not supplied

[Glutaraldehyde - fixed human umbilical cord vein as a small diameter arterial substitute. Experimentation on the monkey].

Autologous saphenous veins, the preferred substitute material for aorto-coronary, femoro-popliteal and femoro-tibial by-pass, are usable in only 70% of individuals in need of such procedures. The development of small diameter substitute arteries is therefore essential to broaden the pool of patients who could benefit from this class of cardiovascular surgery. Existing substitutes, however, present major difficulties and have had limited success. In this laboratory, an attempt has been made to develop a vessel of 3 millimetres or less in diameter derived from human umbilical cord processed in glutaraldehyde. This substitute can be stored in 45% ethanol or dessicated by critical point drying. This device had been implanted as a segment of abdominal aorta in eight primates (Macaca fascicularis). Preliminary results are disappointing. The indicate that retention of a patency for more than a year post-implantation is difficultly achievable and that connective tissue hyperplasia leading to occlusion at the anastomoses is a major problem. Similar but larger diameter by-passes in the order of 6-8 millimetres should be investigated in greater detail, in order to better establish the "in-vivo" behavior of this class of tissue prosthesis. This would address the more fundamental issues pertaining to the clinical usefulness of fixed biological tissue by-pass devices.

Animals↗
PubMedDate not supplied

[A pleasant death].

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Attitude to Death↗