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Biomedical subjects

M Lemaire

Publications and source records attributed to M Lemaire.

At least 145 records · Page 8Linked to original sources

[Chromosome aberrations produced in human lymphocytes by in vivo and in vitro irradiation].

The production of chromosome aberrations in vivo has been studied in lymphocytes from a patient undergoing a wholebody treatment with gamma-radiation up to a cumulative dose of 1.4 Gy. These results were compared with the observations performed on whole blood samples irradiated in vitro with doses from 0.05 up to 2 Gy of gamma-rays. The frequency of chromosome aberrations, particularly the dicentrics, was found to be similar in vivo and in vitro. The yield of dicentrics could be best related to the dose by using a linear-quadratic model in both cases, the ratio of the coefficients a/b being of 0.56 and 0.69 Gy, respectively in vivo and in vitro. These observations confirm that in vitro dose response curves may be used to evaluate accurately an in vivo absorbed dose.

Chromosome Aberrations↗

Reinforcement of tendons and ligaments with carbon fibers. Four years, 1300 cases.

Carbon fibers have a remarkable quality of compatibility with the ability to induce collagenous tissue, but the growth cannot be controlled and may be troublesome if excessive. Replacement of tendons and ligaments by carbon fibers requires a minimum of three months of immobilization, the time necessary for the newly formed tissue to be effective. It is possible if there is no other choice, as, for example, in surgery of old Achilles tendon ruptures, or in reconstruction of ligaments if all autogenous material has been used in previous operations. The author currently uses carbon fibers not to replace tendons or ligaments but to reinforce some weakness of their surgery. The technique of the reinforcement in surgery of the medical collateral ligament of the knee, in reconstruction of the medial patellar retinaculum, and in surgery of tendinitis of Achilles tendon or patellar ligament has been developed in the treatment of more than 1300 cases.

Achilles Tendon↗

Self-renewal and maturation of immature T-cell progenitors within PHA-induced agar T-cell colonies.

T-cell colonies derived from peripheral blood mononuclear cells plated in agar with phytohemagglutinin (PHA) contain about 5-7% E-, OKT3-, OKT6-, TdT-, SIg- cells phenotypically similar to bone marrow precursors since they are also RFB1+, OKT10+, HLA-DR+, and PNA+. These cells can generate secondary E+, OKT3+ T-cell colonies when replated in the presence of both PHA and a colony-promoting activity distinct from the T-cell growth factor, Interleukin 2. These observations suggest that E-, OKT3- cells detected in primary PHA-induced T-cell colonies belong to a pool of prethymic cells which are able to mature into T-lymphocytes of T4 and T8 type in the absence of the thymic microenvironment.

Clone Cells↗

Study of the diagnostic value of the dexamethasone suppression test in endogenous depression.

The diagnostic value of the dexamethasone suppression test (DST) in "endogenous" depression was evaluated in 209 psychiatric inpatients. A high incidence of abnormal DST results was observed in "endogenous" depressives (52%), schizo-affective (69%) and borderline patients (38%). However, 25% of the patients with other psychiatric disease also failed to suppress on the DST. Diagnostic criteria, previous history of alcoholism, psychiatric drug treatment, age and sex did not significantly affect DST performance. The present data do not indicate that the DST represents a highly specific marker of "endogenous" depression.

Borderline Personality Disorder↗

[Postero-internal menisco-capsular disinsertions associated with chronic instabilities of the knee caused by rupture of the anterior cruciate ligament].

Posterior menisco-capsular tears of the medial compartment of the knee can be considered as a complication of rupture of the anterior cruciate ligament and the consequent medial instability. The lesion is more a capsular lesion than a true meniscal one and it is related to an excessive stress on the oblique fibres of the ligament of Hughston attached to the meniscus. The diagnosis is based on arthrography made with meticulous technique. The lesion must be differentiated from true meniscal tears because it can be sutured. One hundred and twenty five such lesions have been operated on and reviewed after a follow-up of an average of two years. The technique must be very precise to prevent any secondary lesion due to surgery and to avoid any plaster cast immobilisation. The results have been satisfactory in 69 p. 100. They should be improved with more accurate surgical technique and with more precise indications.

Arthroscopy↗

[Vertebral osteonecrosis. Apropos of 4 cases with slow spinal cord compression in 1 case].

The authors report on four cases of aseptic osteonecrosis of the vertebral body in adults (VON). Among these, one patient, in whom histological data were available, presented with a slow spinal cord compression syndrome (SSCCS). This complication is uncommon since only one other similar case has been reported so far (4). VON thus remains an underestimated etiology of SSCCS by non-tumoral compression fracture of the vertebral body. Diagnosis is based on the roentgenograms which evidence osteocondensation with "gaseous dissection" of the vertebral body, the latter being considered as pathognomonic of this disease. The etiopathogeny is still unknown. Treatment is purely symptomatic and the course has always been favorable.

Aged↗

Intravenous cyclosporine kinetics in renal failure.

Kinetics of the novel immunosuppressive cyclosporine were determined in four patients with terminal renal failure. After a short intravenous infusion (2.05 to 3.5 mg/kg in 4 hr), blood and plasma concentrations were measured (HPLC and radioimmunoassay [RIA] up to 36 hr. After infusion, concentration curves of the drug were characterized by a rapid initial fall (t 1/2 alpha 0.10 +/- 0.03 hr), followed by a biphasic elimination phase with corresponding t 1/2s of 1.08 +/- 0.25 hr (t 1/2 beta) and 15.8 +/- 8.4 hr (t 1/2 gamma). The volumes of distribution, calculated from whole blood concentrations (HPLC), were 0.140 +/- 0.48 l/kg (volume of the central compartment) and 3.49 +/- 2.65 l/kg (volume of distribution at steady state), whereas systemic clearances were 0.369 +/- 0.08 l/hr/kg. Blood levels measured by RIA exceeded the HPLC values after the fourth hour by up to 100%, indicating the production of cross-reacting cyclosporine metabolites. Plasma concentrations were considerably lower than in whole blood. Elimination of unchanged cyclosporine in patients with renal failure appears to be of the same order as in those with normal kidney function. Modification of the initial dosage regimens is therefore probably not required.

Chromatography, High Pressure Liquid↗

Lymphocyte chromosome aberrations in patients undergoing radiation therapy for mammary carcinoma.

Patients undergoing radiation therapy for mammary carcinoma have been cytologically examined for the presence of polycentric chromosomes in their peripheral blood lymphocytes. The mean values of the observed yields can be fitted to a quadratic function. Due probably to a lower number of lymphocytes exposed the curve now obtained gives a smaller aberration yield than the dose effect curves published earlier for patients given telecobalt therapy.

Adult↗

[Chronic anterior and internal instabilities of the knee. Theoretical study. Clinical and radiological diagnosis].

Antero-medial instability of the knee comprises 96 p. 100 of all knee instabilities. In most instances, the instability is moderate and cannot be analyzed without an adequate understanding of the anatomy and mechanics of the joint. They usually occur after forced movement in medial rotation which ruptures the anterior cruciate ligament and may rupture the postero-medial ligament. Less frequently, they appear after a strain in abduction, flexion and lateral rotation. Some degree of hyper-extension may be added to the primary causal strain. Diagnosis is mainly based on the physical examination which determines the type of surgical procedure that should be made. An anterior draw sign and a click in medial rotation are present when the anterior cruciate ligament is torn. When these signs are very marked, it implies an associated tear of the postero-medial ligament. Standard X-rays and arthrography are most important. Arthroscopy is not of great value and only makes it possible to visualize the meniscus lesions which are important for prognosis. The author describes an original concept of the mechanics of rotation of the knee and the pathogenesis of lesions of the medial capsulo-ligamentous layer.

Arthroscopy↗

[Chronic anterior and internal instabilities of the knee. Treatment].

The effective treatment of antero-medial instability aims to restore mobility which contra-indicates a long post-operative period of plaster cast immobilisation and a passive repair of the ligaments. Satisfactory techniques allow early mobilisation without the use of a plaster cast. They are difficult to perform and need precision. Lesions at the upper end of the medial ligament are best treated by a plastic procedure using the gracilis and lesions of the lower end by use of the semi tendinosus. It is particularly important to determine the precise position of the upper insertion of the medial ligament, to determine the ideal tension of the released ligaments and capsule, to fix the tendons through the bone and to avoid any plaster immobilisation. Walking without weight-bearing is allowed until the fifteenth day. The time off work was about 60 days. The results were satisfactory provided that the lesions were not too old and there were no lesions of the articular cartilage. Associated meniscus lesions were treated by partial resection or repair by suture.

Chronic Disease↗