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Biomedical subjects

P Leclerc

Publications and source records attributed to P Leclerc.

At least 19 recordsLinked to original sources
PubMed1992

Decrease in calmodulin concentrations during heparin-induced capacitation in bovine spermatozoa.

Concentrations of the intracellular Ca(2+)-mediator calmodulin (CaM), were measured by radioimmunoassay during heparin-induced capacitation of bull spermatozoa. Heparin reduced sperm CaM concentrations in a dose-dependent manner corresponding with an increase in in-vitro fertilization rates. Such reductions were observed after heparin treatment for 4-6 h, which is in agreement with the length of the capacitation period in bulls and was concomitant with an increase in CaM concentration in the incubation medium, suggesting translocation of CaM from the spermatozoa to the surrounding milieu. This CaM translocation was inhibited partly by the protease inhibitor benzamidine, suggesting a role for the sperm protease in this process.

Acrosome↗
PubMed1990

Decreased binding of calmodulin to bull sperm proteins during heparin-induced capacitation.

The 125I-calmodulin gel overlay procedure was used to evaluate the effect of a heparin treatment on the calmodulin-binding proteins of bull spermatozoa. At concentrations that increase the in vitro fertilization rate of in vitro-matured oocytes, heparin induced a decrease in the binding to calmodulin (CaM) in 3 sperm proteins of 28, 30, and 49 kDa. The binding of these proteins to CaM was higher when Ca2+ was absent from the overlay procedure, and this binding was negatively correlated to the fertilization rate. These results suggest that sperm capacitation is associated with a decrease in the binding of CaM to the 28, 30, and 49 kDa sperm CaM-binding proteins. Implications of such a decrease are discussed.

Animals↗
PubMed1989

Effect of heparin on the expression of calmodulin-binding proteins in bull spermatozoa.

A 125I-labelled calmodulin gel overlay procedure in the presence and the absence of Ca2+ was used to evaluate bull spermatozoa calmodulin-binding proteins. Frozen spermatozoa were thawed, washed and incubated for 6 h before being processed for SDS polyacrylamide gel electrophoresis and the 125I-labelled calmodulin gel overlay procedure. In non-incubated spermatozoa, up to 14 binding proteins were detected. Some exhibited greater calmodulin binding in the presence of Ca2+ while others exhibited greater binding when Ca2+ was absent. When heparin (2 micrograms/ml) was present in the incubation medium, a decrease in the calmodulin binding to the proteins of Mr 28,000 and 30,000 was detected in the presence of Ca2+ and EGTA. This effect of heparin was time- and dose-dependent and was increased by the presence of the acrosin inhibitor benzamidine. Sperm capacitation could thus be related to a decrease in the binding of calmodulin to these proteins.

Animals↗
PubMed1989

[Comparison of 2 systems of blood culture: Signal and Bactec].

Two Bactec bottles (aerobic and anaerobic) and one single bottle Signal were used for detecting bacteremia in 405 patients (47 children and 358 adults). The two blood culture Signal and Bactec aerobic were continuous shaking for up to 24 hours. 10.3 p. cent of patients had positive cultures (62.3 p. cent Gram +, aero-anaerobic bacteria). Nine bacteremia were detected by only one system (4 for signal, 4 for Bactec) 77.1 p. cent of 83 strains were positive on the two systems together, but 7.2 p. cent only in the Bactec and 15.6 p. cent only in the Signal. The delay of growth give an advantage to the Bactec (67 p. cent in 24 hours). The advantages and the disadvantages of the two systems were analysed.

Adolescent↗
PubMed1989

[Latent and postpartum thyroiditis. Prospective study].

Thyroid evaluation was performed in 85 women at childbirth, then between 2 and 7 months, and 14 months later. Transient subclinical hypothyroidism was found in one woman; antithyroid antibodies were found in 10 and were persistent in 6, suggesting a late thyroiditis. For these 6 cases, 5 HLA typing showed 3 Locus DR4. The proportion of antithyroid antibody was the same in a reference population. This finding would be in agreement with the hypothesis of a latent thyroiditis, revealed by pregnancy. Relative iodine deficiency in France could explain the low frequency of post partum thyroiditis in the present study.

Female↗
PubMed1988

[Peripheral bronchopulmonary cancers. Diagnostic efficiency of fibroscopic samples. Prospective study on 561 patients].

The purpose of this french multicentric study was to evaluate the diagnostic accuracy of samples collected by fibroscopy in peripheral lung cancer with normal endoscopy. Five hundred and sixty-one patients entered the study; a tumour had been diagnosed in 350 of them (62 p. 100). Among these 350 patients, 147 were examined with the help of a light-amplifier screen, and a positive diagnosis was made in 97 (66 p. 100). Guided sample collection in the pathological area (biopsy, brushing, transcatheter aspiration) proved much more rewarding than unguided sample collection (biopsy of the bronchus, simple aspiration or cytology of 3-day sputum): 45 p. 100 positive results versus 18 p. 100 (P less than 0.001). However, sputum cytology still had good diagnostic value since it provided by itself the diagnosis in 14 p. 100 of the cases. Results were significantly inferior in tumours less than 3 cm in diameter.

Adult↗
PubMed1988

Cytogenetic study of parthenogenetically activated bovine oocytes matured in vivo and in vitro.

Three experiments were performed to evaluate the potential for parthenogenetic activation of bovine oocytes in in vitro fertilization systems and to determine the chromosome complement of the resulting parthenogenotes. In the first experiment, immature oocytes from slaughtered cattles were matured in vitro in Defined Medium (DM) for 24 h to simulate in vitro fertilization conditions. Subsequently, a portion was fixed, and the remainder were transferred to rabbit oviducts. Oocytes were then cultured for 6-8 h or for 24 h with Colcemid present during the last 6 to 8 h and fixed on slides and examined. In the second experiment, mature oocytes were collected from the preovulatory follicles, and the oocytes were subjected to the same culture as in experiment I. In the third experiment, oocytes were treated as in experiment II, except that instead of transfer to rabbit oviducts, they were cultured an additional 48 h in vitro. In experiment I, 131 oocytes were fixed after culture in DM. Of the 79 oocytes analyzed in the pre-rabbit group, 71 (90%) were at the second meiotic metaphase (MII), and 8 (10%) were at pre-MII stage; none were activated. After transfer to rabbits, 291 were fixed. Of these, 80 were analyzed; 37 (46.3%) were MII, 7 (8.6%) were pre-MII, and 36 (45%) were activated. Of the 36 activated oocytes, 26 (72.2%) were haploid, 4 (11.1%) were diploid, 1 (12.8%) was tetraploid, and 5 (13.8%) were in the process of endoreduplication. In experiment II, 51 oocytes were fixed after culture in DM of which 36 (70.6%) could be analyzed; 30 (83.3%) were MII, and 6 (16.7%) were pre-MII. After culture in the rabbit, 68 were fixed of which 27 (39.7%) could be analyzed. Of these 27, 20 (74.1%) were MII, and 7 (25.9%) were activated; 6 were haploid, and 1 was endoreduplicating. In experiment III, 30 oocytes were fixed at the end of the culture period; only 10 could be analyzed of which 8 (80%) were MII and 2 (20%) were pre-MII. In all, 46% of in vitro and 26% of in vivo matured oocytes were activated, based on chromosomal analysis. Of those activated, the majority (74.4%) were haploid, suggesting that activation occurs at or after completion of MII. Endoreduplication appears to be one of the mechanisms leading to the formation of diploid and polyploid parthenogenotes.

Animals↗
PubMed1986

[Respiratory complications of anticancer chemotherapy].

Pulmonary toxicity associated with chemotherapy is still rare, but its incidence may increase with intensive and iterative regimens. Following a review of the four main drugs responsible for lung toxicity (bleomycin, methotrexate, busulfan and BCNU), the authors underline the risk of combined chemotherapy and radiotherapy. To recognize, at an early stage, the signs suggesting lung toxicity is essential to reduce its extent and, above all, to exclude other pathologies which often have the same clinical and radiological features. Only histological studies provide evidence of toxicity. Treatment is frequently disappointing; the only hope of regression lies in withdrawal of the responsible drug and corticosteroid therapy.

Antineoplastic Agents↗
PubMed1985

[Postpartum definitive hypothyroidism. 7 cases].

Seven cases of hypothyroidism developed within 6 months of delivery are reported. Radioimmunoassays regularly showed very low thyroxin levels and high thyroid-stimulating hormone levels, thus confirming that the thyroid deficiency was of peripheral origin. A significant rise in antimicrosomal or antithyroglobulin antibodies was noted in 5 cases. One patient had HLA-B8 and 4 had HLA-DR3, which was not significantly different from the prevalence in the regional population. In contrast with the transient post-partum hypothyroidism reported mainly in Japan, the condition proved to be permanent in 6 patients followed up for more than two years. The increased frequency of HLA-DR3 and 5 recently described in thyroiditis with transient post-partum thyrotoxicosis was not found in our series. It would appear that pregnancy, which is a period of immune incompetence, may disclose a latent lymphocytic thyroiditis.

Adult↗
PubMed1977

[Drug sensitivity of Haemophilus sp. and transfer of resistance into E. coli (author's transl)].

From June 1973 to July 1976, 742 strains of Haemophilus influenzae and parainfluenzae, isolated from clinical specimens, were routinely tested for in vitro sensitivity to twelve antibiotics: penicillin, ampicillin, cephalothin, streptomycin, kanamycin, gentamicin, chloramphenicol, tetracyclin, minocyclin, erythromycin, sulfamethoxazol, trimethoprim. 61 strains were found resistant to one or more of these antibiotics (ampicillin, kanamycin, chloramphenicol and tetracyclin). The MICs of 23 antibiotics were determined by the agar dilution method on most of the resistant strains and on 60 sensitive strains isolated during the same period and considered as control. 21 strains transferred their resistance determinants into E. coli K12; 23 plasmids were obtained isolated from these strains: 2 strains contained two different plasmids. 90% of the transconjugants were stable after repeated subcultures.

Anti-Bacterial Agents↗