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Biomedical subjects

J Lecoeur

Publications and source records attributed to J Lecoeur.

14 recordsLinked to original sources
PubMed2000

Interplay between atomic and mesoscopic order on gold vicinal surfaces

Self-organization on Au(1,1,1) vicinal surfaces provides a unique opportunity to study the interplay between atomic and mesoscopic order. First, experimental results demonstrate the different interactions between steps and surface reconstruction on Au(1,1,1) vicinal surfaces. Depending on the step atomic structure, lines of discommensurations are found to be either parallel or perpendicular to the step edges. This leads to a complete understanding of the mesoscopic self-organization on theses surfaces, which drastically depends on the step structure. This points out the crucial role played by the edge energy cost which can monitor the faceting periodicity in a wide range of values.

Journal Article↗
PubMed1990

Corrosion protection of metal implants by hard biocompatible ceramic coatings deposited by radio-frequency sputtering.

Most metals used for orthopaedic and stomatology implants and prostheses belong to the families of titanium or nickel-based and cobalt-based superalloys designed for advanced technology industries (e.g. space, aeronautic and nuclear industries). Ideal materials should be as insoluble and biologically compatible as possible. In the present paper the corrosion behaviour of Ni-Cr and Co-Cr alloys in biological media is evaluated through potentiodynamic polarization tests. It is shown that these metals exhibit some minor release of the component elements and degradation products, which may induce cytotoxic and allergic effects. The corrosion resistance of these alloys can be strongly enhanced by hard ceramic coatings deposited by radio-frequency sputtering. The biocompatibility of coated and uncoated metals is compared from differentiated human cell cultures.

Chromium Alloys↗
PubMed1990

Accelerated ageing of metallic biomaterials: principle and results.

Electrochemical methods such as voltammetry and chronoamperometry are very useful in the study of biodegradation processes. Voltammetry gives qualitative information on the behaviour of a biomaterial in an electrolytic medium. Accelerated ageing of a metallic biomaterial can be obtained using chronoamperometry. Quantitative information on elements released in a solution is also obtained.

Biocompatible Materials↗
PubMed1988

[Isolated rupture of the left main-stem bronchus during intubation with a Carlens tube].

A case is reported of bronchial rupture due to a Carlens double-lumen tube. A 73 year old male patient was to undergo a double right lower and middle lobectomy for carcinoma. All went well and as expected until 20 min after the start of left-sided unilateral ventilation by way of the double-lumen tube. A sudden increase in the inspiratory pressures led to the discovery, first, of a leak around the cuff, and then, air bubbles in the mediastinum. Surgical exploration showed up the 4 cm long rupture in the pars membrana of the left main bronchus through which the cuff was herniating. The patient was reintubated and the rupture surgically repaired. The right upper lobe had not been ventilated for 45 min and there were signs of micro-atelectasia. The immediate postoperative course was rather stormy, with severe cardiac failure, recurring right upper lobe atelectasia and bilateral pulmonary infection. The patient was only definitely weaned from the respirator 40 days after the surgical incident. Although such complications with double-lumen tubes are rare, they must be recognized and surgically repaired very rapidly. A few simple rules to prevent these complications are discussed.

Aged↗
PubMed1987

[A new case of cyst of the common bile duct with an anomaly of the bilio-pancreatic convergence].

A case of common bile duct cyst operated upon in a 2 1/2 year old girl is used as a basic for discussing the forms associated with anomaly of convergence of common bile and wirsung's ducts. The latter, of dysembryoplastic origin, appears to be the cause of this type of cyst. These forms are atypical in that no mass is palpable and they are frequently complicated by a pancreatitis. They constitute the majority of Japanese cases when the anomaly is investigated. Its detection is possible by retrograde catheterization or more rarely during perioperative cholangiography, the only possibility in the very young infant. Different operative technics are outlined, taking into account principally the risk of secondary malignant changes and the possible performance of a hepatico-duodenal anastomosis without increasing the risk of an ascending angiocholitis.

Child, Preschool↗
PubMed1977

[Assessment of 81 traumatic vascular lesions of the limbs (author's transl)].

A review of 81 cases of vascular trauma of the limbs in 75 patients treated at the Grenoble University Hospital from 1967 to 1975 confirms the classical etiological, pathological and clinical findings. Analysis of the results led us to emphasise the necessity of bone and vascular repair which should be complete from the start, verified by peroperative radiological control. The application of now well-established rules to the treatment of vascular trauma should lead to a better prognosis in the case of popliteal lesions (76 p. cent of good results out of 17 revascularisations).

Adolescent↗
PubMedDate not supplied

[Our experience of mesenterico-caval anastomosis with prosthetic interposition (report of 30 cases) (author's transl)].

The authors report their experience of 30 mesenterico-caval anastomoses with prosthetic interposition according to Drapanas's technic. From the point of view of the operative indications, they have never carried out a prophylactic operation. In 19 cases, the operation was carried out as an emergency for inefficacy of the medical treatment. In 11 cases, a cold operation was performed, either to prevent eventual hemorrhagic recurrence (8 cases) or for chronic ascites (3 cases). Half the patients belonged to group C with a poor surgical risk. There was only one case of post-operative thrombosis due to a technical error, and two cases of secondary thrombosis. The overall mortality was 60%. But when the patient was of group A or B the mortality was only 20%. The survivors are those in whom the operation was rapid and the blood loss minimal. To conclude, the authors the necessity of better selection of patients, and rapid operation without bleeding.

Adult↗
PubMedDate not supplied

[Repair problems of infected iatrogenic lesions of the femoral trifurcation. Review of 7 cases (author's transl)].

The authors report on seven cases of infected iatrogenic lesions of the femoral trifurcation. One case was a false aneurism consecutive to a femoral vein catheterization. In 5 cases an arterial lesion followed angiography according to Seldinger. In the last case aetiology was undetermined. Local symptomatology was always associated to systemic infection. The causative germ was a pseudomonas in 3 cases an a staphylococ in 4 others. Operation was performed in emergency in all cases because of a fissure or a rupture of the artery. The authors performed: one simple arterial suture, one resection with plastic graft, one resection with venous graft and 4 resections with double vein graft. This last procedure appears useful for lesions situated at the femoral division.

Adult↗