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Biomedical subjects

G Michel

Publications and source records attributed to G Michel.

At least 163 records · Page 9Linked to original sources
PubMed1996

Quantitative assessment of hepatitis C virus RNA and IgM antibodies to hepatitis C core in chronic hepatitis C.

BACKGROUND/AIMS: IgM antibodies to hepatitis C virus have been found in a variable proportion of patients with chronic hepatitis C. We have evaluated whether IgM anti-core antibodies correlate with viraemia or hepatic injury in chronic hepatitis C. METHODS: Serum from 106 patients with chronic hepatitis C with varying stages of disease were tested for IgM anti-core hepatitis C virus by immunoassay. All patients were seropositive for IgG antibody to hepatitis C virus by second-generation ELISA; 25 had histologic cirrhosis and 57 chronic hepatitis. IgM anti-core was detected in 84/106 (79.2%) patients. HCV-RNA was tested by branched (bDNA) signal amplification assay or by polymerase chain reaction in 92 patients. RESULTS: All IgM-anti-HCV positive patients had detectable HCV-RNA. Seventy of 87 (80.5%) HCV-RNA-positive patients were IgM anti-core positive. Levels of IgM anti-HCV were significantly higher in patients with HCV-RNA detected by bDNA than in those who were bDNA negative, but there was no correlation between HCV-RNA concentrations and IgM anti-HCV levels. Of the 84 patients with positive results for IgM anti-core hepatitis C virus, 59 (70.2%) had abnormal alanine aminotransferase levels. The levels of IgM anti-core hepatitis C virus were likewise significantly higher in those with abnormal alanine aminotransferase levels. There was no difference in the percentage of patients with a positive IgM anti-HCV, or in levels of IgM anti-core hepatitis C virus in those with chronic hepatitis versus cirrhosis. CONCLUSIONS: These data suggest that the majority of patients with chronic hepatitis C virus infection are IgM anti-core hepatitis C virus positive, and the detection seems to be associated with viral replication and biochemical evidence of hepatic necrosis. IgM anti-core hepatitis testing may prove useful as an adjunct in the clinical assessment of patients with chronic hepatitis C.

Adolescent↗
PubMed1996

A phase II trial of partially incompatible bone marrow transplantation for high-risk acute lymphoblastic leukaemia in children: prevention of graft rejection with anti-LFA-1 and anti-CD2 antibodies. Société Française de Greffe de Moelle Osseuse.

Bone marrow transplantation (BMT) from matched sibling donors has been useful for the treatment of acute lymphoblastic leukaemia in children with a poor prognosis but is not available to more than two-thirds of patients who do not have a matched allogeneic donor. This study was undertaken to assess one strategy of marrow graft rejection prevention when alternative marrow sources such as HLA-phenoidentical unrelated volunteers and HLA-partially incompatible relatives were used. Results have been compared with two matched groups of children with the same risks factors and disease status who underwent HLA-genoidentical or autologous BMT. The conditioning regimen was the same for the three groups of patients; in the study group anti-LFA-1 and anti-CD2 monoclonal antibodies combined with T-cell depletion of the marrow was added to prevent graft rejection and graft-versus-host disease. Nineteen patients were included and followed for a median of 25 months (14 months to 3 years). Bone marrow engraftment occurred in 83% of the evaluable patients. Post-transplantation infectious diseases were the most frequent causes of death in the study group, occurring in 31% of patients. No fatal infections occurred in the two control groups. Post-transplantation relapse of leukaemia occurred in 26% of study group's patients, in 58% of autologous BMT control group's patients and 5% of HLA-genoidentical allogeneic group's patients. The event-free survival was 83% in the HLA-genoidentical control group, and 30% and 24% in the study group and in the autologous control group, respectively. In conclusion, a high rate of engraftment was achieved by the use of anti-LFA-1 and anti CD2 antibodies. Occurrence of a long-lasting immunodeficiency, however, led to a high incidence of lethal infections and relapses. Combined approaches are therefore to be investigated accelerating immune reconstitution after transplantations of T-depleted HLA partially incompatible marrow.

Adolescent↗
PubMed1996

Comparison of antimicrobial properties of monoterpenes and their carbonylated products.

Some monoterpenes and their carbonylated products were evaluated for their antibacterial and antifungal properties. The carbonylation of tested monoterpenes was shown to increase the bacteriostatic and fungistatic activities specifically by the contact method. Concerning the killing effects, only (1R,2S,5R)-isopulegol, its carbonylated products, and (R)-carvone showed significant bactericidal activities, particularly against Enterococcus faecium and Escherichia coli above a concentration of 10 microliters/ml. A fungicidal efficiency of (1R,2S,5R)-isopulegol and (R)-carvone against Aspergillus niger was also noted. It seems that the presence of an oxygenated function in the framework increases the antimicrobial properties. However, monoterpenes were more active using a micro-atmosphere method.

Anti-Bacterial Agents↗
PubMed1996

[Changes in the shape and growth of motor endplates of mm. fibularis longus, semitendinosus and longissimus in pigs].

Age-related changes in motor endplates were studied in the fibularis longus, semitendinosus and longissimus muscles in pigs. They develop from small, compact AChE-active figures in fetuses to typical myoneuronal synapses with a branched subsynaptical structure of AChE-active units. High correlations were found between size of endplates and both myofibre diameter and body mass. Growth analyses with respect to age, as well as allometrical approaches, showed that endplate growth slightly precedes that of myofibres, with both having similar growth patterns. The morphological changes, however, imply that the increment of synaptical area could lag behind that of myofibres.

Acetylcholine↗
PubMed1996

Radioprotective effects of a protein-free hemodialysate in human epidermis.

The accidental or therapeutic exposure of human skin to ionizing radiation is known to cause the radiation syndrome with its various manifestations. The aim of the study was to investigate the potential radioprotective effects of the protein-free hemodialysate Actovegin. After exposure to X-rays (single dose, 6 Gy), 70% of the cells died. In the presence of the hemodialysate, irradiation did not lead to cell death. Instead a slight increase in cell number was observed. A 5-fold increased cell number was found after 6 days when the cells were treated with the hemodialysate alone. To elucidate molecular mechanisms of the observed biological effects the correlation between the expression of the epidermal growth factor receptor (EGFR) and the demonstrated growth activation was investigated. Radiation alone resulted in a clear induction of EGFR, whereas the combination of irradiation and Actovegin treatment led to a strong downregulation after 2 days. Thus, the hemodialysate suppressed one of the radiation-induced effects. Further investigations have to elucidate the role of other proteins which are involved in the signal transduction cascade of tyrosine kinases (e.g. Ras, Raf, MAP kinases) leading to the transcription factor AP-1 in response to radiation under Actovegin treatment.

Cell Count↗
PubMed1996

Allogeneic bone marrow transplantation vs aggressive post-remission chemotherapy for children with acute myeloid leukemia in first complete remission. A prospective study from the French Society of Pediatric Hematology and Immunology (SHIP).

The objective of this study was to compare allogeneic bone marrow transplantation (BMT) with high-dose cytarabine containing chemotherapy in children with acute myeloid leukemia (AML) in first complete remission (CR). One hundred and seventy-one children were enrolled on the LAME89/91 protocol. Induction chemotherapy was a combination of cytarabine and mitoxantrone. After achieving CR, patients who had an HLA-identical sibling donor underwent allogeneic BMT. Children not eligible for BMT received post remission chemotherapy which included two consolidation courses, the second consolidation consisting of high-dose cytarabine with amsacrine and asparaginase. CR was achieved in 149 children (87%). Thirty-two had an HLA-identical sibling donor and were eligible for BMT. These 32 patients, as well as an additional child who had a one antigen HLA-mismatched father, received BMT during first CR. Consequently, 33 patients were analyzed in the BMT group and 116 in the chemotherapy group. The 4-year probability of relapse was 26 +/- 15% in the BMT group and 47 +/- 10% in the chemotherapy group (P = 0.04). The risk of therapy-related death was 3% for BMT and 7.7% for chemotherapy. Disease-free survival (DFS) was 72 +/- 15% in the BMT group and 48 +/- 10% in the chemotherapy group (p = 0.02). We conclude that allogeneic BMT from a matched sibling donor is the treatment of choice for reducing the relapse risk and for increasing DFS in children with AML in first CR.

Amsacrine↗
PubMed1996

Composition of the Lactobacillus acidophilus complex isolated from vaginal flora.

One hundred and fifty human vaginal samples containing a diversity of pathogens or nonpathogens (Gardnerella vaginalis, Streptococcus sp., Staphylococcus sp., Candida albicans. Mycoplasma sp.) were examined for their content in lactobacilli of the Lactobacillus acidophilus complex. Although all samples contained lactobacilli, strains of the L. acidophilus complex were present in only twenty-nine cases. Isolates were further characterized and compared with type strains or reference strains in an attempt to differentiate by phenotypic means the genospecies of the L. acidophilus complex. Data regarding specific activities of beta-galactosidase (beta-gal) and of phospho-beta-galactosidase (P-beta-gal) provided no specific information at the species level within the L. acidophilus complex. DNA-relatedness differentiates this genospecies. Most lactobacilli isolated from the vaginal flora of symptomatic women were genotypically close to L. gasseri CIP 102991T by the technique of DNA/DNA hybridization.

Anti-Bacterial Agents↗
PubMed1996

[Tissue regeneration processes in the bovine mammary gland].

Tissue regeneration within the udder after mastitis is part of the healing process and may lead to restoration of the affected quarter. These in most cases multiple processes differ considerably in shape and size according to the duration and the type of the disease. They are distinct from the more uniform regenerative processes within the lobuli of the gland during colostrogenesis of the dry period.

Animals↗
PubMed1996

[Post-partum malignant amebic colitis. Apropos of a case].

A 26-year old female developed acute fulminant amoebic colitis during the post-partum period, successfully managed by subtotal colonic resection without anastomosis. Fulminant transmural amoebic colitis is a rare life-threatening complication of invasive bowel amebiasis. Pregnancy, delivery, diabetes mellitus and immunodeficiency are the main risk factors. At pathologic examination, bowel wall necrosis can be seen with amoebae present in the lumen of capillary vessels. The diagnosis of amoebic colonic perforation is difficult, especially in a non-endemic area. Conservative surgical management is required in non-perforated forms. If perforated, the bowel must be resected, limited to macroscopic lesions.

Adult↗
PubMed1996

[Krukenberg tumors. Analysis of a series of 28 cases].

We report a retrospective series of 28 patients with Krukenberg tumors treated at the Gustave Roussy Institute from 1973 to 1990. Mean age of these women was 42 years. The patients were classed into two groups: depending on whether the ovarian metastasis (group 1) or the primary cancer (group 2) was discovered first. The primary tumor was identified in 20 cases (18 cases of linitis, 1 tumor of the cecum, 1 tumor of the appendix). The primary tumor remained unknown in 8 cases. Twenty-seven patients underwent radical total hysterectomy or bilateral adnexectomy. Gastrectomy was possible for 11 of the 18 cases of linitis; hemicolectomy and appendectomy were performed for the cecal and appendicular tumors respectively. Diagnosis of a primary tumor of the appendix was made after systematic appendectomy and of two Krukenberg tumors after systematic bilateral adnexectomy. In the first group of patients, both localizations were treated in 6 cases, one in 12 including 4 because gastrectomy was not initially possible and in 8 because the primary tumor was unknown. In the second group, the two localizations were treated in 7 cases, and one in 2 cases because gastrectomy was not possible. Surgery was not performed in one patient due to diffuse carcinosis. Bilateral ovarian metastases were seen in 26 out of the 28 cases and 26/28 had chemotherapy without any appreciable effect. Bone metastasis predominated (9 cases), followed by pleuropulmonary (5 cases) and liver (3 cases) metastasis. Overall median survival was 20 months; 14 months in the first group and 29 months in the second. Appendectomy and exploration of the colon and the stomach were performed in all cases in which the Krukenberg tumor was discovered intraoperatively. An endosonographic exploration of the stomach is recommended if the primary tumor is not localized. Bilateral adnexectomy should always be performed in patients with linitis whatever the age. Surgical treatment of the two localizations is not always sufficient for cure.

Adult↗
PubMed1996

[Histological and histochemical investigations on the structure of udder skin of cattle with special reference to changes during in vivo udder perfusion models].

Generally, the skin of the bovine mammary gland is found to be similar to the skin of the integument. In the epidermis, the stratum lucidum is lacking. A prominent stratum corneum can be observed as well as in the haired areas and in areas without hairs as well. Distinct granules of melanin are located mainly in the stratum basale in pigmented skin areas. By means of the alkaline phosphatase, dendritc cells can be seen in the basal parts of the epidermis. In the corium, collagenous fibres are less thick below the epithelium, whereas coarse bundles are seen deeper in the stratum reticulare. The appearance of multilobal sebaceous glands and apocrine sweat glands is associated with a hair follicle, which occur loosely distributed as single hairs. A large erector pili muscle is situated on the side of the hair slope. The numerous sweat glands with wide diameters appear below the hair papilla, and vary greatly in shape and size. Myoepithelials cells are seen at the periphery of its secretory portions. The small number of differences in all areas of the skin examined, are reduced to differences between haired areas and the base of the teats. The histologic structure of the epidermis remains unchanged by the perfusion. A partly collagenolysis occur in the dermis and subcutis.

Animals↗
PubMed1995

Treatment of acute graft-versus-host disease with methylprednisolone and cyclosporine with or without an anti-interleukin-2 receptor monoclonal antibody. A multicenter phase III study.

A double-blind, placebo-controlled trial of BT563, including 13 European centers, was initiated in October 1989 to compare the efficacy of the combination of in vivo anti-CD25 mAb (BT 563), cyclosporine, and steroids versus placebo and CSA-steroids in the treatment of grade II and III acute graft-versus-host disease (GVHD). Sixty-nine patients participated in the study, which excluded non-genotypically identical allogeneic bone marrow transplant recipients. No statistically significant differences were observed, clinically or biologically, between the 2 groups before the onset of the treatment. Treatment responses were scored during and after the 3-week treatment period (mAb or placebo). Efficacy was evaluated on days 4, 10, 20, 30, and 60 or on any day the patient's condition was found to be deteriorating. Preceding and systemically untreated GVHD of grade I was observed in 59% of the cases. No statistically clinically significant differences between the 2 groups were observed during or upon completion of treatment in GVHD grade. Nine patients in the placebo group and 6 in the active group were withdrawn of the study. Thirteen of these 15 patients were withdrawn because of failure of GVHD therapy (9 in the placebo group and 4 in the BT563 group). At day 20 after onset of the treatment, the response rate was 63% and 70% for the placebo and BT563 groups, respectively (NS). Probability of survival at 1 year was 59% and 66% (NS) for the placebo and active groups, respectively. In conclusion, despite preliminary promising results in the treatment of steroid-resistant acute GVHD, the role of first-line treatment with an in vivo anti-interleukin-2 receptor mAb remains to be determined.

Acute Disease↗
PubMed1995

Amyloid beta peptide induces cytoplasmic accumulation of amyloid protein precursor via tau protein kinase I/glycogen synthase kinase-3 beta in rat hippocampal neurons.

Exogenous application of synthetic amyloid beta protein (A beta) is known to induce neurotoxic effects in rat hippocampal culture. We report here that A beta (25-35) induces accumulation of amyloid precursor protein (APP) derivatives in the cytoplasm of neurons. At the same time, the level of the secreted form of APP released into the culture medium decreases. Tau protein kinase I/glycogen synthase kinase-3 beta (TPK I/GSK-3 beta) antisense oligonucleotide blocked APP accumulation and prevented neuronal death. These results provide evidence that APP accumulation after A beta treatment is regulated by TPK I/GSK-3 beta. A beta neurotoxicity is probably mediated via phosphorylation of tau by TPK I/GSK-3 beta, resulting in an impairment of axonal transport, and cytoplasmic accumulation of APP.

Amyloid beta-Peptides↗
PubMed1995

Effect of the lipopeptide antibiotic, iturin A, on morphology and membrane ultrastructure of yeast cells.

The effects of iturin A, at fungicidal concentrations, on yeast cells were studied by scanning electron microscopy and by transmission electron microscopy. A depression, observed in each iturin A-treated cell, was the consequence of the release of electrolytes and other cytoplasmic components. Iturin A passes through the cell wall and disrupts the plasma membrane with the formation of small vesicles and the aggregation of intramembranous particles. Moreover, iturin A passes through the plasma membrane and interacts with the nuclear membrane and probably with membranes of other cytoplasmic organelles.

Anti-Bacterial Agents↗
PubMed1995

Studies on lipopeptide biosynthesis by Bacillus subtilis: isolation and characterization of iturin-, surfactin+ mutants.

Two mutant strains, M35 and M89, were obtained by UV irradiation from a wild-type Bacillus subtilis producing iturin and surfactin. Sporulation and surfactin production were similar in both mutants and in the parent strain, while the iturin production of M35 was 300-fold less than that of the wild-type strain; M89 did not produce any iturin. The analysis of the incorporation of sodium [1-14C]acetate into cellular lipids and lipopeptides showed that M89 still synthesized beta-amino fatty acids, the lipid moiety of iturin.

Anti-Bacterial Agents↗
PubMed1995

Overproduction and properties of the mannuronate alginate lyase AlxMB.

In previous studies (Malissard et al., FEMS Microbiol. Lett. (1993) 110, 101-106), the alginate lyase AlxM of the marine bacterium ATCC 433367 was produced in Escherichia coli TC4/pAL-A3 with a yield of 50 micrograms per litre of culture. The polypeptide chain was cleaved between two cysteine residues, C169 and C183, themselves linked by a disulphide bridge. AlxM has now been overproduced in E. coli BL21(DE3)/pAL-Sur/pLysS. Under conditions in which formation of inclusion bodies can be avoided, the enzyme is synthesized as a catalytically active, water-soluble, unnicked polypeptide with a yield of 32 mg per litre of culture. It has been purified to protein homogeneity using a one-step procedure. The nicked AlxMA and unnicked AlxMB alginate lyases have identical alginate-degrading activities at high salt concentrations.

Amino Acid Sequence↗