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Biomedical subjects

G Michel

Publications and source records attributed to G Michel.

At least 361 records · Page 20Linked to original sources
PubMed1989

Action of mycosubtilin, an antifungal antibiotic of Bacillus subtilis, on the cell membrane of Saccharomyces cerevisiae.

Mycosubtilin, an antibiotic of the iturin group, inhibits the growth of Saccharomyces cerevisiae by a fungicidal action. Increasing concentrations of mycosubtilin decrease the incorporation of radioactive precursors into proteins, RNA and polysaccharides without specificity. Yeast spheroplasts are lysed by mycosubtilin. Its action on the cytoplasmic membrane induces important modifications of the membrane permeability: nucleotides, proteins and lipids are released from the cells. These releases increase with increasing concentrations of mycosubtilin.

Antifungal Agents↗
PubMed1989

[Sarcoma of the uterus. A clinical study apropos of 50 surgically treated cases at the Gustave Roussy Institute. Review of the literature].

From 1970 to 1987 fifty patients with uterine sarcoma who have been operated at the G. Roussy Institute (IGR) were studied. The histological material was reviewed according to the W.H.O. classification and the Hendrickson and Kempson's criteria. Staging was done on surgical and histological findings according to the pTNM classification of the UICC for endometrial carcinoma. There were 22 cases of heterologous malignant mixed müllerian tumor (MMT), 5 cases of homologous MMT, 20 cases of leiomyosarcoma (LS), 1 high grade stromal sarcoma, 1 low grade stromal sarcoma (stromal myosis (SM], 1 adenosarcoma. There were 22 cases of stage T1 T2, 23 cases of stage T3 T4 and 5 TX (first surgery outside IGR). Total hysterectomy with bilateral salpingo-oophorectomy was performed in 86% of the cases. Radiation therapy was performed in 26 cases mostly external pelvic irradiation associated with endobrachytherapy. "Cyvadic" combination chemotherapy was used in 16 cases associated with platinum in few cases. There were 2 postoperative deaths, 11 cases of progression and 37 cases of complete remission (CR). Of the 37 cases of CR, 10 patients are alive with NED 6 months to 10 years after diagnosis in 2 cases of MMT. 27 patients presented recurrence or metastasis. Of the 22 patients with pelvi-abdominal recurrence, 10 had debulking surgery (one total pelvic exenteration (PE), three posterior PE). Among them five are alive 14 to 78 months later (3 LS, 1 AS, 1 SM). Thirty percent of the patients developed lung metastasis. The overall five-year survival was 42 +/- 16% (28 patients) (Kaplan-Meier's method), similar to literature data.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Secondary cytoreductive surgery in ovarian cancer.

During the 8-year period from 1976 to 1984, 202 patients with a primary ovarian cancer underwent a second-look laparotomy at the Institut Gustave-Roussy (Villejuif). One hundred and nine patients had a macroscopic tumour, in 77 of which there was clinical evidence of disease before the laparotomy. Fifty-seven patients underwent an optimal resection of the tumour (largest residual tumour less than 2 cm) and 52 underwent non-optimal cytoreductive surgery or isolated biopsies. In 22 cases the optimal resection necessitated a bowel resection. Survival curves suggest: (1) that the removal of macroscopic residual disease does not improve life expectancy except in the cases of optimal resection without bowel resection. (2) When there is evidence of disease before the second-look operation the prognosis remains the same whatever the surgery performed.

Adolescent↗
PubMed1989

[Pseudotumoral nasopharyngeal sarcoidosis in the child. Apropos of a case].

Rhino-pharyngeal, involvement is rare in sarcoidosis, and exceptional in children. The authors report a case of pseudo-tumoral involvement of the cavum in a 9 year old child, revealed by locoregional complications. Close collaboration between clinicians and the pathologist enabled correct etiological diagnosis.

Airway Obstruction↗
PubMed1989

[The value of MRI in a case of cerebro-meningeal miliary carcinomatosis of melanotic origin].

Despite the frequency of cerebral metastases from melanoma, there have been very few papers on this subject in the radiological literature. We report one such case, original by its disseminated carcinomatosis appearance and by the disassociation between computed tomography and magnetic resonance imaging, illustrating the greater sensitivity of the latter examination. In view of the fact that 11 to 13% of patients with a cerebral metastasis from melanoma are asymptomatic, there may be a place for screening of these patients by MR imaging. The association of neurological lesions and cutaneous naevi raises the problem of neurocutaneous melanosis (degenerating phakomatosis).

Adult↗
PubMed1988

Prognostic factors in gestational trophoblastic tumors. A multivariate analysis.

One hundred sixty-two gestational trophoblastic tumors (GTT) were treated at the Institute Gustave-Roussy, Villejuif, France, from 1975 to 1985. Sustained complete remission (CR) was obtained in 146 patients (90%). All 97 patients with no histologic diagnosis of choriocarcinoma were cured, including 19 patients considered at high risk initially. Among 65 histologic chariocarcinoma patients, 16 died (CR, 75.5%) including seven initially nonmetastatic patients. Using a univariate analysis, all factors tested in the whole group of patients were more or less significant except for age and parity. However, when the same variables were tested in patients considered at high risk initially, only three factors were statistically significant. Those three factors were the only ones associated with a statistically significant higher relative death risk (RR) on multivariate analysis and are as follows: an antecedent nonmolar pregnancy (RR = 4.3; P less than 0.01); initial presentation with more than one metastatic organ (RR = 7.4; P less than 0.01); and primary resistance to single agent (RR = 18.8; P less than 0.0001) or multi-agent chemotherapy (RR = 26.1; P less than 0.0001). It seems that those three factors, together with a histologic diagnosis of choriocarcinoma, are the prognostic factors that discriminate patients with unfavorable outcomes among the high-risk group.

Choriocarcinoma↗
PubMed1988

An amphibian two-domain 'big' neurophysin: conformational homology with the mammalian MSEL-neurophysin/copeptin intermediate precursor shown by trypsin-sepharose proteolysis.

A 'big' frog (Rana esculenta) neurophysin, encompassing sequences homologous to mammalian MSEL-neurophysin and copeptin, has been passed through a trypsin-Sepharose column in order to compare its conformation with that of the two-domain intermediate precursor isolated from guinea pig. Whereas the polypeptide possesses 8 arginine residues, only two cleavages were observed located in a putative inter-domain sequence (at Arg-94 and Arg-114). Because free vasotocin has been isolated from the frog, it is assumed that pro-vasotocin has a three-domain conformation similar to that of pro-vasopressin but processing in amphibians involves only one step rather than two steps as in mammals.

Amino Acid Sequence↗
PubMed1988

Intensive chemotherapy with high doses of BCNU, etoposide, cytosine arabinoside, and melphalan (BEAM) followed by autologous bone marrow transplantation: toxicity and antitumor activity in 26 patients with poor-risk malignancies.

Twenty-six patients (median age 33 years) with poor-risk malignancies were treated with high-dose combination chemotherapy associating BCNU-etoposide-cytosine arabinoside and melphalan (BEAM) followed by autologous bone marrow transplantation (ABMT). Twenty-one patients had malignant lymphomas, three, acute lymphoblastic leukemia (ALL), and two, malignant thymomas. Eleven patients (group 1) were not in complete remission (CR) at the time of BEAM, and fifteen patients (group 2) were in CR. Hematological recovery occurred in all patients. The duration of aplasia and the non-hematological toxicities were similar in both groups. Ten of the eleven patients (group 1) evaluable for response achieved CR and one achieved partial remission (PR). Five patients relapsed, and five are in continuous CR with a short follow-up (median 8 months). Among the fifteen patients in CR at the time of BEAM (group 2), four patients relapsed and ten patients are in unmaintained continuous CR with a median follow-up of 15 months (one patient died in CR). The disease-free survival is 53%, with 29% for patients receiving BEAM while in relapse (group 1) and 65% for patients receiving BEAM while in CR (group 2). These data indicate that BEAM followed by ABMT can produce a high antitumor response with an acceptable toxicity in patients with poor-risk malignancies.

Adolescent↗
PubMed1988

The incidence of type 1 (insulin-dependent) diabetes mellitus in subjects aged 0-19 years in Luxembourg: a retrospective study from 1977 to 1986.

A decrease in the incidence of Type 1 (insulin-dependent) diabetes mellitus in the age group 0-14 years has been observed from north to south over north-western Europe. To evaluate whether this trend could be found in Luxembourg (a small country between the Netherlands and France) we performed a retrospective study over a period of 10 years. Information concerning all Type 1 diabetic patients (aged 0-19 years at diagnosis), diagnosed between January 1, 1977 and December 31, 1986 was obtained through paediatricians, internists, general practitioners and the Luxembourg Diabetes Association (LDA). The LDA was used as the ascertainment group (to estimate the real number and incidence of Type 1 diabetes mellitus). During the study period 91 Type 1 diabetic patients aged between 0-19 years were diagnosed. An incidence of 11.2 was found in boys (0-19 years). Girls in the same age group showed a considerably lower incidence of 8.8. Standardised incidence (using as standard the world population) revealed an almost similar incidence in the Netherlands and Luxembourg (respectively 10.3 and 10.2) for the age group aged 0-14 years. In France a considerably lower incidence is found (3.6). To what extent different methodology contributes to the differences remains to be clarified. Further prospective studies are necessary to investigate the role of environmental and genetic factors.

Adolescent↗
PubMed1988

Mucopolysaccharidosis-like cellular alterations in chondrocytes of rats treated with tilorone.

The dicationic amphiphilic compound tilorone was previously shown to interfere with the lysosomal degradation of sulfated glycosaminoglycans (GAGs) of cultured cells and to cause mucopolysaccharidosis-like alterations in several organs of rats. Since chondrocytes belong to those cells that are severely affected in cases of inherited mucopolysaccharidoses, we wished to know whether this also holds true of the experimentally induced mucopolysaccharidosis. Young rats were treated with tilorone (50-80 mg/kg of body weight) for 2-17 weeks; chondrocytes in tracheal and costal cartilage and in the epiphyseal growth plates of the tibia and ribs were examined by electron microscopy and cytochemistry (acid trimetaphosphatase and staining with Cuprolinic Blue). The tracheal and costal chondrocytes showed numerous abnormal clear vacuoles. Some of them could be identified cytochemically as lysosomes filled with polyanionic storage material, probably sulfated GAGs. In the epiphyseal plate, only the resting chondrocytes were markedly affected, whereas those of the remaining zones were hardly altered; this may be due to the short life span of these chondrocytes in rat growth plates. The present results show that chondrocytes participate in the experimental mucopolysaccharidosis and suggest that, under normal conditions, the lysosomes of chondrocytes have to cope with a considerable load of GAGs.

Animals↗
PubMed1988

Restricted alpha- and beta-adrenoceptor affinity of sulfoconjugated catecholamines in human mononuclear leukocytes, platelets, and fat cells and reduction of the postreceptor mechanisms.

The physiologic significance of the racemic 3-O-sulfate esters of epinephrine (EPI-3-O-S) and norepinephrine (NE-3-O-S) as well as 4-O-sulfoconjugated dopamine (DA-4-O-S) was evaluated. For this purpose these conjugated catecholamines (CA) were synthesized and investigated with respect to their alpha 2- and beta 2-adrenoceptor affinities and their biological activity in three different human cell systems: in mononuclear leukocytes (MNL), platelets, and fat cells. The unequivocal identification and the minimal degree of contamination of the synthesized sulfoconjugates with free CA was proved by 1H-NMR and by high-performance liquid chromatography with amperometric detection (HPLCA) respectively. In isolated human MNL, beta-adrenoceptor affinities of these conjugated CA were determined in competition experiments with the lipophilic nonspecific radioligand (-) 125I-cyanopindolol (ICYP) and, in addition, with the hydrophilic ligand 3H-CGP12177. With both ligands the affinity constants (KD) of the sulfoconjugated CA under investigation were about 100- to 1000-fold higher when compared with the respective free amines. Moreover, these sulfoconjugated CA per se induced no intracellular production of cyclic adenosine monophosphate (cAMP) in MNL. In comparison with the free amines, metanephrine (MN) and normetanephrine (NMN) showed a highly reduced competitive potency on the MNL beta-adrenoceptors labelled with 3H-CGP or ICYP. The KD values for MN and NMN in competition studies with ICYP were 10- and 5-fold higher than in those with 3H-CGP respectively, indicating a restricted access of MN and NMN to intracellular receptors. The adenylate cyclase system was not stimulated at all by MN or by NMN. In human platelets EPI-3-O-S and NE-3-O-S neither competed with the specific alpha 2-adrenoceptor antagonist 3H-yohimbine nor elicited any aggregation response at all. MN and NMN exhibited an about 40-fold reduced affinity for alpha 2-adrenoceptors in platelets when compared with the respective free amines and elicited no aggregation response at all. However, in the presence of MN and NMN the EPI- and NE-induced platelet aggregation was dose-dependently attenuated. These findings reveal an alpha 2-adrenoceptor antagonistic potency of MN and NMN. In human adipocytes EPI-3-O-S and NE-3-O-S were 100- to 1000-fold less potent to inhibit lipid mobilization via alpha 2-adrenoceptors as well as to stimulate the beta-adrenoceptor mediated lipolysis when compared with free CA.

Adipose Tissue↗
PubMed1988

Influence of Tween 80 on the mycolic acid composition of three cutaneous corynebacteria.

Changes in the mycolic acid composition of three cutaneous strains of corynebacteria were caused by the addition of Tween 80 to the culture medium. Gas chromatography-mass spectrometry showed that the carbon chain length and the degree of unsaturation had been affected: the levels of corynomycolic acid with 36 carbon atoms and two double bonds increased significantly.

Corynebacterium↗
PubMed1988

Studies on the hexose region of the lipopolysaccharide from a low virulence strain of Salmonella typhimurium.

The structure of the hexose region of the lipopolysaccharide from M206 strain, a mutant of Salmonella typhimurium having reduced virulence, was partially determined. Immunological tests indicated cross-reactions of anti-(M206) antiserum with wild-type C5 and Ra mutant strains. Data obtained on chemical composition, periodate oxidation, acetolysis, methylation and analysis by gas chromatography/mass spectrometry show that M206 type lipopolysaccharide contains the common core polysaccharide of Salmonella which was substituted in position 4 of the subterminal glucose unit by a disaccharide: D-glucosyl 1----3 D-galactose. This substitution is probably related to the slight virulence of M206 strain.

Acetates↗
PubMed1988

Studies on the biosynthesis of beta-amino acids, the lipid moiety of iturins A, in Bacillus subtilis.

The biosynthesis of the beta-amino acid components of iturins A was studied in comparison to the biosynthesis of fatty acids. Palmitic acid was incorporated into the lipid moiety of iturins A when it was added to the culture medium of the iturin producer Bacillus subtilis. Addition of unlabeled palmitic acid enhanced the formation of straight-chain beta-amino acids and addition of valine or leucine increased the production of branched beta-amino acids. These modifications correlated with modifications in the corresponding biosynthesized fatty acids.

Anti-Bacterial Agents↗