Biomedical subjects

L Bordenave

Publications and source records attributed to L Bordenave.

63 records · Page 4Linked to original sources

PubMed1991

Rationale for the design of biomaterials and the evaluation of their biocompatibility.

The biocompatibility of a material can be considered as the ideally expectable result of its interactions with living tissues with which it is interfaced. This property determines the ability of devices involving this material in their constitution, to correctly assume their ascribed function; reciprocally a bad fitting, between devices and their intended use, coming from a non-optimized design or from an inappropriate prescription, may alter the original biocompatibility of constitutive materials. Accordingly, the actual biocompatibility of a biomaterial depends upon both its intrinsic properties and the application in which it is involved. Such considerations must be taken into account by specialists who try to design more performant biomaterials, or new assist devices, should they be implantable or not; but they draw also methodological guidelines for the evaluation of the biocompatibility of these biomedical products.

Biocompatible Materials↗

PubMed1990

Biocompatibility of polyacrylamide microcapsules implanted in peritoneal cavity or spleen of the rat. Effect on various inflammatory reactions in vitro.

The biocompatibility of polyacrylamide microcapsules was investigated by implanting microcapsules in the peritoneal cavity or the spleen of rats. The capsules were retrieved every four weeks for twenty weeks. They remained isolated and free in the peritoneal cavity, but led to a slight inflammatory reaction in the spleen. These results were confirmed, in vitro, by determinations of chemiluminescence and interleukin I levels, and by evaluation of attachment and growth of human fibroblasts. The microcapsules did not enhance these inflammatory reactions, and they were a poor support for cellular proliferation.

Acrylic Resins↗

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

Biocompatibility of carbon-carbon materials: blood tolerability.

Carbon-carbon composites are well known in the field of aerospace technology. Such composites have been proposed to be used as biomaterials, particularly in contact with blood. To evaluate their haemocompatibility, samples were tested in vivo and in vitro, using radiotracers. In vivo study showed the accumulation of platelets on the exposed surface material with any surface morphology, whereas platelet concentration in blood remained constant. In vitro study allowed us to distinguish, among entrapped platelets, active adhering platelets from those mechanically retained and it appeared that the bulk structure of materials influenced the adhesion mechanism of platelets.

Animals↗

PubMed1989

Experimental evaluation of a gelatin-coated polyester graft used as an arterial substitute.

Protein coating and endothelial cell preseeding have been proposed and studied as improvements to arterial prostheses. In this paper, an impervious polyester vascular graft which had been coated with cross-linked gelatin was compared to a porous one over a period of up to 8 months in dogs. This evaluation involved in vivo methods using radio tracers to study patency and thrombogenicity and in vitro controls of the healing processes. The main advantages offered by coated grafts over uncoated include the absence of preclotting and better biointegration.

Animals↗

PubMed1986

Topographic and dynamic radioisotopic investigations of interactions between biomaterials and blood components.

Functional investigations using radionuclides to study protein adsorption and platelet adhesion onto biomaterials are described. The authors' novel methods use radiotracers with a dynamic technique. This allows direct observation of the interaction between blood, or simpler biological substances, and artificial materials. Several radiotracers were used in this study, including 111In-platelets, 123I-fibrinogen, 123I-antithrombin III, and 99mTc-tagged red blood cells. The detectors employed were a semiconductor diode or gamma-camera equipped with special collimators. The acquisition and treatment of data were performed with an original device. These methods allowed precise comparisons, especially between platelet adhesion upon different materials in the form of tubes and also protein adsorption and desorption. The results are discussed in terms of materials to be used for work in vivo.

Adsorption↗

PubMedDate not supplied

[Bone remodeling assessment after total hip replacement].

It is known that total hip arthroplasties (THA) lead to adaptative remodeling changes resulting in periprosthetic bone loss. DEXA is recognized as the most precise and accurate method for quantifying bone mineral density (BMD) in humans. The present study compares over two years after THA, DEXA data to those of urinary deoxypyridinoline (uDPYR), a pyridinium crosslink of bone collagen fibrils proven to be a reliable bone resorption marker. 41 patients (21 postmenopausal female, 20 male) underwent cemented THA. Urinary excretion of DPYR was determined using ACS : 180 SE (Bayer Diagnostics) and normalized for creatinine excretion while periprosthetic BMD (g/cm2) was measured (QDR 4500, Hologic), at post-operative day, 3 months, 1 year and 2 years after surgery. The 7 periprosthetic subregions (R1-R7) of the Gr en method are the regions of interest for evaluating bone remodeling process. uDPYR showed a significant decrease between postoperation and 1 year: 10.6 0.80 vs 4.8 0.6 nmol/mmol, p < 0.0001 (Wilcoxon Test for paired samples and statistical significance accepted at p < 0.05) and non significant variation between 1 and 2 years. Between post-operation and 3 months global and regional BMDs decrease significantly (p < 0.04) followed by an increase in distal BMD (R3, R4, R5). During the second year BMD increases also for other regions. At 2 years BMD in distal regions is recovered except in the proximal R7 when comparing post-operation and 2 years, pattern consistent with literature. Thus, a discrepancy is observed between uDPYR and DMO results that does not allow us to use a bone resorption urinary marker to monitore local bone periprosthetic remodeling.

Adult↗

PubMedDate not supplied

[CA 125 kinetic pattern during chemotherapy].

CA 125 is a tumoral marker that may be elevated in non-mucinous epithelial ovarian tumours but is neither sensitive nor specific enough to be used as a diagnostic tool. However, CA 125 serum concentration variations can be used for monitoring chemotherapy efficiency. This study concerns 75 patients who underwent surgical cytoreduction followed by a first-line chemotherapy during which CA 125 serum variations were studied by calculation of mono-exponential regression curve slopes and half-lives. Persistence of tumour residues was evaluated by tomodensitometry and/or second look surgery du- ring a post-chemotherapy check-up. A slope > - 0,0156 (half-life > 44,43 d) was a perfect predictor of a persistent tumour; conversely, a slope < - 0,0340 (half-life < 20,39 d) reliably predicted the absence of detectable tumour. We propose a personalised graphic representation of CA 125 variations to follow-up chemotherapy. Its exploitation, in association with classical prognostic factors, could improve patients monitoring.

Biomarkers, Tumor↗

PubMedDate not supplied

[Thyroglobulin mRNA detection in the follow-up of thyroid carcinomas].

The follow-up of differentiated carcinomas is based on the detection of thyroglobulin (Tg) in the serum. Tg assays are immunoassays that may be hampered by autoantibodies directed against Tg. To avoid this problem some authors advocated the use of mRNA extraction and RT-PCR amplification. Quantitative methods have been developed to achieve a good analytical sensitivity. These techniques may then be alternative to the Tg assay when anti-Tg antibodies are present in the serum should it be proven they display pronostic values reliable enough for clinical diagnosis use.

Follow-Up Studies↗