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Biomedical subjects

A Leger

Publications and source records attributed to A Leger.

16 recordsLinked to original sources
PubMed1995

[Molecular typing by pulsed field gel electrophoresis of Pseudomonas (Burkholderia) cepacia isolated from a nosocomial infection].

Because of the emergence of Pseudomonas (Burkholderia) cepacia, isolated among patients from an intensive care unit of the Hôpital Pellegrin (Bordeaux), strains were studied in the aim to determine the source and the mode of transmission of the bacteria. The study was performed on 44 isolates of P. cepacia from 21 patients (23 strains) or from the environment (16 isolates from ventilators and five from the distilled water used for these ventilators). Susceptibility to 23 antibiotics of these strains and endonuclease restriction polymorphism on their total DNA were determined. Pulsed field gel electrophoresis was performed after digestion of the genomic DNA, using three restriction enzymes. Results obtained by analysis of genotypic characteristics demonstrated the clonal origin of the P. cepacia epidemy in the different intensive care units, but did not localize the source of the infection.

Aminoglycosides↗
PubMed1994

Rowing performance and selected descriptive, field, and laboratory variables.

The purpose of this study was to determine the relationships among measures of rowing performance and selected descriptive, field, and laboratory variables. Rowing performance of 20 intercollegiate oarswomen was assessed using a 2,500-m time test on a Concept II rowing ergometer, the rower's competitive experience, and the coach's ranking of the rowers. The oarswomen also underwent standardized descriptive tests including anthropometric measurements, field tests including 90-s rowing ergometer distance and weight lifting tests, and laboratory tests including VO2max and isokinetic knee extensor strength tests. Rowing ergometer times were highly related to competitive experience (rho = -0.86; p < 0.01) and coach's ranking (rho = 0.87; p < 0.01). VO2max was the only other variable to produce correlations greater than 0.71 with rowing performance. Although most of the correlations observed in the present study were poor to modestly high, they do document and quantify relationships, and suggest that training and testing techniques should be modified to be more rowing specific and that their usefulness with respect to positive transfer and prediction should be examined.

Adult↗
PubMed1993

[Syndrome of resistance to thyroid hormones].

Although rare, thyroid hormone resistance syndrome should be suspected on a biological profile combining high thyroid hormone and non-suppressed TSH plasma levels. Resistance to thyroid hormone can be classified into 3 forms: generalized, pituitary and peripheral, all three showing tissue resistance heterogeneity from one person to another, and from one tissue to another in the same subject. In the generalized and pituitary forms, thyroid hormone levels are high with paradoxically normal or increased TSH levels. The TRH test still stimulates TSH secretion, and only the highest doses of T3 successfully suppress TSH secretion. In the generalized form, euthyroidism is usual, whereas in the pituitary form hyperthyroidism requires treatment in order to lower TSH secretion. In the peripheral form, various symptoms of thyroid hormone deficiency may be observed, contrasting with normal T3, T4 and TSH serum levels, and requiring supraphysiological doses of T3 for correction. In most cases, familial occurrence can be evidenced, with an autosomal dominant or sometimes recessive mode of inheritance. Genetic analysis has identified, in the generalized form, more than 10 mutations of the thyroid hormone receptor beta gene, all resulting in an alteration in the T3 binding domain of the receptor. In the autosomal dominant form, tissue resistance may result from a "dominant inhibitory effect" of the normal receptor function by the mutant receptor. All these thyroid hormone resistance syndromes constitute exceptional models for studying the mechanisms of action of thyroid hormones. Simultaneous observations of the mutated receptors with various clinical and biological phenotypes should further our understanding of thyroid hormone receptor function.

Drug Resistance↗
PubMed1993

Changes in rowing ergometer, weight lifting, vertical jump and isokinetic performance in response to standard and standard plus plyometric training programs.

The purpose of this study was to compare standard (S-weight plus rowing ergometer training) and standard plus plyometric (S+P-weight plus rowing ergometer training, plus plyometric exercises) programs on sport-specific and non sport-specific tests. Twenty-four female rowers completed the weight training or the weight training plus plyometric exercises three times per week and rowing ergometer training four times per week, 1 hr per session for 9 wks. Analysis of variance tests were used to compare S (n = 11; 5 novice and 6 experienced rowers) and S+P (n = 13; 7 novice and 6 experienced rowers) programs on the following sport-specific tests: 1) time to row 2,500 m and 2) distance rowed in 90 s; and on the following non sport-specific tests: 1) leg press, 1 RM, 2) leg press endurance, 3) bench pull 1 RM, 4) bench pull endurance, 5) vertical jump, 6-9) isokinetic knee extensor peak and average power during concentric and eccentric muscle actions and 10) angle of occurrence of peak torque during concentric muscle actions (isokinetic knee extension). Although experienced oarswomen scored significantly higher than did novice oarswomen on eight of 12 tests (p < 0.04), both levels of rower responded similarly to training. No significant differences were observed post-training between the S and S+P training programs (p > 0.05). These results do not discount the value of plyometric exercises, but indicate that the jump exercises used offered no advantages to intercollegiate oarswomen.

Body Weight↗
PubMed1992

Antithyroid hormone antibodies induced by interferon-alpha.

A 40-yr-old woman known for a multinodular goiter had hyperthyroidism. Treatment with antithyroid drugs and iodine therapy was effective. One year later, she received interferon-alpha for treatment of essential cryoglobulinemia. At that time, the patient was euthyroid. Testing for antithyroglobulin, antimicrosome, anti-TSH receptor, and antithyroid hormone antibodies was negative. After a 1-yr course of interferon-alpha, goiter enlargement was noticed. Apparently elevated free T3 and T4 serum values were measured by RIA, contrasting with clinical euthyroidism and normal TSH values. High serum levels of antithyroid hormone antibodies were found in the patient's serum, using a radiolabeled hormone immunoprecipitation assay. Antithyroglobulin and antimicrosome antibodies titers were also elevated and paralleled antithyroid hormone antibodies. After cessation of interferon-alpha therapy, clinical status and TSH levels remained normal, while thyroid hormone values and antithyroid hormone antibody levels progressively normalized. To our knowledge, this is the first report of antithyroid hormone antibodies induced by interferon-alpha. Since thyroid dysfunction is described in 10-15% of treated patients, the fact that interferon-alpha can induce antithyroid hormone antibodies has important implications: 1) the prevalence or intensity of thyroid dysfunction could be overestimated; and 2) artifactually elevated free T3 and T4 serum values could lead to inappropriate therapy of thyroid disease or cessation of interferon treatment.

Adult↗
PubMed1991

Tracking with a restricted field of view: performance and eye-head coordination aspects.

Vision through a restricted field of view (RFOV) is becoming increasingly common in aviation with the use of helmet mounted displays. Our first experiment investigated the influence of a narrow (20 degrees) binocular RFOV on performance during head-free visuo-manual tracking of a wide range (+/- 85 degrees) horizontally moving target. Second, the effects of two levels of RFOV (20 degrees, 70 degrees) on a similar tracking task presented with various eccentricities were compared to full field of view (FOV). Eye and head movement around the yaw axis were recorded and analyzed versus head-free visual pursuit alone. Tracking performance appeared moderately impaired when RFOV was set to 20 degrees, but did not improve with a 70 degrees field. Discomfort due to unusually large head movements was ruled out as a causal factor. Visuo-manual tracking apparently implies a need for head stability. RFOV degrades this basic requirement which, in turn, could explain performance impairment. Analysis of eye-head coordination characteristics following FOV task conditions supports this hypothesis.

Adult↗
PubMed1988

Detection of myocarditis during the first year after discovery of a dilated cardiomyopathy by endomyocardial biopsy and gallium-67 myocardial scintigraphy: prospective multicentre French study of 91 patients.

The purpose of this study was to assess the frequency of inflammatory lesions in the myocardium of subjects with dilated cardiomyopathy and to determine if there was any correlation between the results of two methods of evaluation, one (endomyocardial biopsy) invasive and the other (gallium-67 scintigraphy) noninvasive. Of 115 subjects recruited in seven centres, 91 met the inclusion criteria (left ventricular dilatation greater than or equal to 100 ml m-2 and ejection fraction less than 55% with normal coronary arteriography) and had endomyocardial biopsy (mean five specimens) and Ga-67 myocardial scintigraphy after several days. Scanning was considered doubtful 19 times and positive 13 times. The histologic count of mononuclear cells in the myocardial interstitium in 20 fields was greater than 5 cells field-1 in only four cases. No correlation was found between the two methods. Subjectivity in the choice of the criterion of positivity of Ga-67 scintigraphy and difficulties in identifying lymphocytes upon pathological examination were the major problems encountered. Despite limitations, both techniques suggest that cellular infiltrates are minimal and quite infrequent in dilated cardiomyopathy.

Adolescent↗
PubMed1986

Multifactorial study of prognostic factors in differentiated thyroid carcinoma and a re-evaluation of the importance of age.

A multivariate analysis of prognostic factors has been carried out with 375 cases of differentiated thyroid cancer (DTC) treated in the same centre by total thyroidectomy and 131I therapy. The patients have been followed for 5 to 23 years. The isolated prognostic roles of age, sex, clinical stage and histology were confirmed, but these factors were found to be strongly interrelated. Multifactorial analysis was conducted following Cox's model. It demonstrated that the prevalent role of clinical staging (nodular versus lobar or massive form) is as important as the initial presence of metastases (P = 0.0001). Histological assessment of differentiation, age and sex were of lesser importance. Thus, the most significant prognostic variable is clinical stage. These data must be taken into account when formulating management protocols for DTC.

Adolescent↗
PubMed1983

Immunological studies of autoimmune thyroid disorders: abnormalities in the inducer T cell subset and proliferative responses to autologous and allogeneic stimulation.

Various immunological parameters were investigated in patients with Hashimoto's thyroiditis (HT) and Graves' disease (GD). The total T cell numbers were significantly decreased in both diseases whether they were enumerated by E rosetting or by pan-T cell monoclonal antibodies (OKT3 and anti-Leu 1). This diminution was due to a loss in the inducer T cell subset (OKT4+/Leu 3a+) whereas the cytotoxic/suppressor T cells (OKT8+/Leu 2a+) were present at normal levels in both diseases. The B cells were significantly higher in GD patients than in controls but were not modified in HT patients. Monocyte percentages remained unchanged and DR+ cells were slightly increased in the two diseases. On the other hand, T lymphocyte responses to stimulation by autologous or allogeneic cells were significantly impaired in GD but not in HT whether cultures were performed in autologous plasma or AB serum. In addition, lymphocytes from normal subjects were unable to proliferate in auto- or allo-MLR in the presence of plasma from GD patients but they were reactive in the presence of HT plasma or AB serum. Taken together, these results suggest that the patients with autoimmune thyroid disorders exhibit a T cell imbalance within the OKT4+/Leu 3a+ subset. Moreover, this abnormality is correlated with the observation that autoreactive and alloreactive cells are defective in GD.

Adult↗
PubMed1981

Motion sickness caused by rotations about Earth-horizontal and Earth-vertical axes.

Rotation at constant angular velocity about the head's Z-axis, with the rotational axis horizontal (barbecue-spit rotation), causes motion sickness and illusory perceptions of bodily movement. To determine whether such rotations about the head's X- and Y-axes cause similar effects, and to test the validity of the mismatch theory of motion sickness, more than 200 tests (using vertical axes as well as horizontal axes) were administered to 14 subjects. Three different visual conditions were also investigated: normal external vision, vision of only the inside walls of the rotating capsule, and eyes closed in the dark. In Earth-horizontal rotation, the X- and Y-axis stimuli were found to be equally as effective in provoking sickness as was the original Z-axis stimulus, and a comparable loss of perception of gravity occurred for all three stimuli. The horizontal axis stimuli were found to be very effective in producing sickness in all the three visual conditions, but the external vision condition was significantly less effective than the other two conditions. The findings were generally inconsistent with the mismatch theory.

Adult↗
PubMedDate not supplied

[Paradoxical effects of iodine overload on thyroid function].

Any chronic iodine overload resulting from long term ingestion of a medication or the administration of a non-resorbable contrast medium, may result in a goitre with or without hypothyroidism, and in particular in patients with a past history of thyroid disease. By contrast, the administration of iodine is no longer indicated in the treatment of enedmic goitres since the hypothesis of an iodine deficiency in the pathogenesis of such goitres may be excluded in most countries, and in particular western countries, and the risk of the development of thyrotoxicosis in such patients is not negligeable. It would thus be desirable that iodine no longer be used in the composition of medications when its presence is not indispensalbe and where, furthermore, it may contribute to developement of an increasingly disturbing iatrogenic complication.

Aged↗