Biomedical subjects
Publications and source records attributed to G Michel.
Hematological and clinical features of 36 mainly Algerian patients with S-beta thalassemia are reported. These data, compared with those reported in the literature, showed a higher prevalence of aseptic necrosis and gall stones, probably related to the large predominance of S-beta zero-thalassemia (30 cases) and a long (14 years) median follow-up period.
Twenty-four perinatally HIV infected children received early treatment as soon as the diagnosis of viral contamination was established. In 13 cases (group 1), this diagnosis was based on a viremia and/or antigenemia during the first 6 months of life. In 11 cases (group 2), children were more than 15 months-old and had a positive HIV antibody test. Therapy included azidothymidine (AZT, 400 mg/m2/d) and the prevention of secondary infectious complications with intravenous immunoglobulin and cotrimoxazole. With a median follow-up of 26 months, we reported no case of severe secondary infection and no case of encephalopathy. Hematological side effects of AZT were rarely observed. Only one patient developed anemia. In all other cases, the only hematological abnormality was macrocytosis of red blood cells. Before treatment, the mean value of T4 cells age-adjusted count was 96, 86 and 91%, respectively, for groups 1, 2 and the entire study group. At the time of analysis, these values were 64, 62 and 63% respectively. This decrease was statistically significant for group 1 and for the entire study group, but did not reach statistical significance for group 2. These data show that AZT is probably insufficient as a long-term therapy for HIV infected children. Other therapeutic approaches need to be developed in the future, notably the combination of anti-retroviral drugs.
A strain of Streptomyces which produced stendomycin, a lipopeptide antibiotic, was grown in culture media containing various amino acids as nitrogen substrates. The nature of the fatty acid component of stendomycin was dependent on the nature of the amino acid present in the medium, but this did not affect antibiotic activity. Modifications in the peptide moiety resulted in a loss of antifungal activity.
Treatment of healthy volunteers by Ribomunyl, whether or not in association with in vitro antibiotics (amoxicillin or josamycin), has been earlier demonstrated to be an efficient stimulant of PMN functions (adhesion and migration). This second double-blind study versus placebo was performed on 17 patients with acute respiratory infections (placebo group: eight subjects; Ribomunyl group: nine subjects). Ribomunyl treatment (four days) associated with antibiotherapy (amoxicillin) induced a significant increase of PMN adhesion (p = 0.014) with no significant effect of the placebo (p = 0.30) and no significant difference between the initial level of PMN adhesion of the two groups (placebo-Ribomunyl).
The antifungal activity of iturin A and its interaction with erythrocyte membranes were enhanced in the presence of surfactin. The modification of the properties of iturin A was explained by the formation of mixed iturin A-surfactin micelles. Such mixed micelles were easily generated when both lipopeptides were in aqueous solutions in the absence of mineral salts but the formation of these micelles did not occur when the solutions contained a high molarity of mineral cations.
Explore the source record for details and available documents.
The authors present five new cases of entomophthoromycosis observed during three years of histopathology in Cameroon. Three classic cases of rhinoentomophthoromycosis. In one case, Conidiobolus coronatus was isolated. Two cases of subcutaneous entomophthoromycosis, without isolation of the germ. In one observation, the clinical and histological aspect suggested mucormycosis post entomophthoromycosis. An immunofluorescence technique showed the Basidiobolus haptosporus to be the real cause.
In the Gustave-Roussy Institute the standard protocol of limited stages (IB, proximal II) of cervix carcinoma, combines endocavitary brachytherapy (low dose rate) and surgery (BSOH + lymphadenectomy) are eventually followed by external beam irradiation. According to age of patients and to prognostic factors adaptations of this combined treatment are discussed: young patient (40 years) with small tumor, large volume of primary tumor (4 cm), lymphatic node involvement. Analysis of the results in 2 series of patients entirely treated at the Gustave-Roussy Institute: survival, local control, metastases, complications.
Reinvestigation of surfactin, a previously studied peptidolipid surfactant from Bacillus subtilis, by fast-atom-bombardment mass spectrometry and 1H-NMR spectroscopy, as well as by chemical methods, revealed the presence of a closely related second constituent. This new compound, [Val7]surfactin, differs from the known surfactin by the C-terminal amino acid residue which is valine instead of leucine.
The idiopathic hypereosinophilic syndrome (IHS) is extremely rare in childhood and relationships of this syndrome with myeloproliferative diseases are controversial. We reported the observation of a 7-year-old girl suffering from an IHS with myelofibrosis. A clonal cytogenetic abnormality, trisomy 8, was detected in the bone marrow cells of this child. This is the decisive proof of a myeloproliferative disorder. IHS with myelofibrosis is usually considered as unresponsive to corticotherapy. In our case, corticotherapy resulted in a rapid, complete, and lasting disappearance of myelofibrosis. Complete remission of the disease, however, was not achieved and the trisomy 8 persisted after treatment.
Human MSEL-neurophysin has been dissected into two halves by endopeptidase Lys-C, taking advantage of a peculiar Lys59-Ala60 bond. Two sub-domains, N-terminal (1-59) and C-terminal (60-93), have been separated. These sub-domains have been purified by reverse-phase high pressure liquid chromatography and identified by their N-terminal sequences. The N-terminal fragment comprises two chains 1-18 and 19-59, because of the presence of a second lysine residue in position 18, whereas the C-terminal fragment (60-93) is a single chain. Hormone-binding experiments have been carried out using vasopressin or vasopressinyl-Gly-Lys-Arg and testing the ability of the hormone-neurophysin complex to precipitate at pH 3.9 with 10% NaCl. The N-terminal sub-domain precipitates in presence of vasopressin in the same way as native neurophysin whereas the C-terminal sub-domain does not. It can be concluded that the hormone-binding site is located in the 1-59 region of neurophysin.
The in vivo effect of immunostimulant treatment, bacterial ribosomes together with membranal proteoglycans (three tablets and three sprays daily during 4 days) in combination or not with in vitro amoxicillin or josamycin (range 5-50 micrograms/ml), has been studied on three related functions of polymorphonuclear cells (PMN) isolated from human blood: adhesion, spontaneous and oriented migration. The immunostimulant treatment always induces an increase of the three parameters. A positive effect of high concentrations of amoxicillin could be also observed on adhesion and gives rise to a great additional impact by associating it with immunostimulant treatment (control: 8.26 PMN/field; assay: 51.55 PMN/field). Spontaneous and oriented migration are not very altered by in vitro antibiotics. A very significant decrease of chemotaxis has been only observed with 50 microgram/ml of josamycin. However, the immunostimulant treatment compensates for this negative effect. The real increase in PMN activation produced by the immunostimulant treatment might extend its indications beyond prevention during antibiotherapy, for example in the acute phase of respiratory infections.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The proteolytic processing of frog (Rana esculenta) proopiomelanocortin in melanotropic cells of the intermediate pituitary gland has been examined through purification of the mature fragments by reverse-phase high-pressure liquid chromatography and microsequencing of isolated peptides. alpha-Melanotropin, beta-melanotropin, Lys-gamma-melanotropin, corticotropin-like intermediate lobe peptide, and hinge peptide have been isolated and chemically characterized. The results show a high preservation in the processing sites of frog proopiomelanotropin when compared to bovine counterparts. They reveal also a great conservation of the processing enzyme equipment of melanotropic cells in tetrapods species. Identification of Lys-gamma-melanotropin suggests the occurrence of an endopeptidase able to cleave between two basic residues. On the other hand alpha-melanotropin does not appear to be N-acetylated, as previously found in the clawed-toad Xenopus laevis, and this feature might distinguish amphibian from mammalian proopiomelanocortin processing.
According to the electron microscopic investigations the most evident sign of the phase of the active involution of the mammary gland in cattle is the occurrence of different great vacuoles with a diffuse content in the cytoplasma of the secretory cells till the 30th day after the beginning of the dry period. Secretory cells which go over in the rest phase show a great reduction of the cell organelles and many filaments and secondary lysosomes or residual bodies. One can observe many macrophages and lymphocytes in the partly enlarged intercellular rooms between the secretory cells and the myoepithelial cells. The myoepithelial cells are adapting to the changing forms of alveoli. The phase of the colostrogenesis is characterised by the enlargement of the cell organelles and the reappearance of vacuoles.
Light microscopical and histochemical investigations were performed on biopsies, which were obtained from the mammary glands of healthy pregnant cows during different stages of the nonlactating period. The results demonstrate characteristic morphological changes in the different phases of the nonlactating period. They can be interpreted as involution and regeneration processes, which occur in the alveoli and interalveolar tissue of the bovine mammary gland during the nonlactating period.
Pseudomonas aeruginosa alginate was covalently coupled to exotoxin A by reductive amination using adipic acid dihydrazide as spacer. The conjugate was composed of 25% alginate and 75% exotoxin A and possessed an average molecular mass higher than 700 kDa as determined by polyacrylamide gel electrophoresis. The conjugate had virtually no ADP-ribosyltransferase activity and a reduced cytotoxicity for TSA8 murine cells, derived from Friend erythroleukemia cells, as indicated by a greater than 50-fold increased LD50. Anti-conjugate antibodies recognized exotoxin A and alginate. A booster injection resulted in markedly increased antibody ELISA titers to both exotoxin A and alginate. The antibodies neutralized the exotoxin A toxicity.