Biomedical subjects
B Michel
Publications and source records attributed to B Michel.
[Acute hemiplegia in children caused by infarction of the internal capsule. Diagnosis by cerebral scanography].
Explore the source record for details and available documents.
Squamous cell carcinoma arising in pemphigus vulgaris during immunosuppressive therapy.
A rapidly growing squamous cell carcinoma developed in an area of active pemphigus vulgaris on the cheek of a 45-year-old woman during treatment with prednisone and cyclophosphamide. This is the first reported case of this phenomenon. The roles of solar and drug carcinogenesis, autoimmunity, and immunosuppression in the pathogenesis of this tumor are discussed.
DNA cloning in Bacillus subtilis. III. Efficiency of random-segment cloning and insertional inactivation vectors.
Random segments of Bacillus amyloliquefaciens and yeast Saccharomyces cerevisiae DNA were used to determine two parameters pertinent to cloning in Bacillus subtilis, the yield of hybrids and the mean size of cloned segments. 10(3) to 10(4) hybrids/micrograms of DNA segments were obtained. Hybrids represented 11--18% of transformants. Mean m. wt. of cloned DNA segments was about 1 x 10(6), substantially lower than 3 x 10(6) found for donor DNAs after digestion with restriction endonucleases. We have cloned a B. amyloliquefaciens DNA segment which complemented a deficiency in B. subtilis hisH and E. coli hisC genes, which encode imidazolylacetolphosphate aminotransferase. The cloning efficiency for this gene was 10 transformed hosts/micrograms of donor DNA. Several B. subtilis insertional-inactivation cloning vectors were examined. One, pHV41, allows inactivation of the kanamycin-resistance (KmR) gene by insertion into its unique Bg/II site. In two other vectors, pHV11 and pHV23, insertion in their unique Kpn site inactivates the tetracycline-resistance (TcR) gene. pHV23 replicates both in E. coli and B. subtilis, and carries unique sites for seven restriction endonucleases (BamHI, EcoRI, HpaI, KpnI, PstI, SalI, XbaI). This makes it one of the most versatile B. subtilis cloning vectors yet described.
Reliability of indirect immunofluorescence testing.
Explore the source record for details and available documents.
[Prostaglandin biosynthesis in psoriatic epidermis (author's transl)].
The biosynthesis of prostaglandins E2 (PGE2) and F2 alpha (PGF2) from exogenous arachidonic acid (AA) was investigated in 12 involved and uninvolved psoriatic epidermis and in 6 normal epidermis. PGE2 and PGF2 were determined by radio-immuno-assay after addition of 25 microgram of AA and 1 hour incubation. The biosynthesis of PGE2 and PGF2 alpha was higher in psoriatic epidermis than in control epidermis but lower in involved than in uninvolved epidermis. The ratio PGE2/PGF2 alpha is decreased in involved epidermis when compared with uninvolved epidermis and with controls. These quantitative and qualitative disturbances of the PG metabolism in psoriatic epidermis might play an important role in the pathogenesis of the disease. They could be responsible for abnormal keratinocyte differentiation and proliferation, lipid membrane abnormalities and abnormal immune response of psoriatic patients.
Pemphigus. Facts, unanswered questions, and speculations.
Explore the source record for details and available documents.
Antinuclear factor and anti-DNA in sera of pregnant women.
Explore the source record for details and available documents.
Electroencephalography in brain edema (127 cases of brain tumor investigated by cranial computerized tomography).
Cranial computerized tomography (CCT) in permitting visualization of cerebral edema in live patients, allows for the first time valid studies concerning the role of reactional edema in the generation of EEG abnormalities related to expanding processes. The authors analyze the results of EEG and CCT in 127 patients presenting cerebral tumor(s), 84 of which were accompanied by reactional edema. The study leads to the conclusion (also demonstrated by certain animal work) that edema per se is only rarely responsible (9.5%) for the EEG abnormalities.
Electroencephalographic cranial computerized tomographic correlations in brain abscess.
The authors studied 19 cases of brain abscess. The investigation included one or more EEG records from 13 patients and one or more cranial computerized tomograms in all cases. In this work the two techniques were associated to establish the diagnosis of cerebral abscess. The EEG is almost always abnormal and pronounced EEG disturbances are, in most cases, sufficient for indicating a diagnosis of a space-occupying process. On the other hand, EEG patterns suggestive of brain abscess were detected in only 38% of the patients. In brain abscess, CCT is of considerable value since the existence of 'suppurative' images was demonstrated in all cases and of these, 70% were characteristic. The association of these two techniques is thus extremely useful in the diagnosis of cerebral abscess, to follow its evolution and to detect postoperative relapse or to evaluate the efficiency of medical management alone.
Appearance of "pemphigus acantholysis factor" in human skin cultured with pemphigus antibody.
These studies deal with the mechanism of pemphigus IgG-induced epidermal acantholysis. When normal human skin was culted with defined medium containing IgG from pemphigus serum, extensive epidermal acantholysis developed and heat-labile proteolytic enzyme(s) were recovered in the culture medium. The enzyme(s) displayed maximal activity at pH 6.5 when a 3H-amino acid-labeled, insoluble epidermal cell material was used as substrate. The enzyme activity increased during the first 3 days of culture and the appearance of maximal activity coincided with the time of onset of acantholysis. Acantholysis did not occur in control cultures incubated with normal IgG and the enzyme did not appear in the medium or in aqueous extracts of cultured tissues. The enzyme(s) is probably not of lysosomal origin because low pH-active proteases characteristic of these organelles remained within the cells. The effects of puromycin on appearance of enzyme activity, acantholysis and cell viability was studied. At cytotoxic concentrations, the appearance of the enzyme(s) and acantholysis were prevented, whereas at less toxic concentrations enzyme activity and acantholysis were not prevented. Because inhibition of protein synthetic rates by puromycin could not be dissociated from the cytotoxic effects, it is uncertain whether enzyme appearance and acantholysis were dependent upon living tissue or on specific protein synthesis. After pemphigus IgG was removed from the conditioned medium by DEAE cellulose and affinity column chromatography, the remaining material contained enzyme activity and caused acantholysis in fresh skin explants. Similar activities were not present in normal IgG-containing conditioned medium or unfractionated epidermal extracts from normal skin. These data indicate that when the pemphigus IgG autoantibody interacts with epidermal cell surface antigens, the cell responds by synthesis or activation of a non-IgG "pemphigus acantholysis factor" (PAF) which may be a nonlysosomal proteolytic enzyme. It is suggested that PAF causes loss of adhesion between keratinocytes and ultimately produces the characteristic acantholytic cells of pemphigus.
Corticosteroids, aurothioglucose and soybean trypsin inhibitor do not prevent pemphigus antibody-induced acantholysis in vitro.
Hydrocortisone, triamcinolone acetonide, aurothioglucose and soybean trypsin inhibitor were added to normal human skin explants cultured with IgG from pemphigus serum to determine if acantholysis could be prevented. At the therapeutic concentrations used none of these compounds prevented binding of the autoantibody to the epidermal target cells, and none prevented acantholysis. These experiments support the concepts that the pemphigus antibody alone is responsible for producing the acantholytic lesions of pemphigus, that the therapeutic effectiveness of steroids and gold salts is probably due to their ability to reduce serum autoantibody titres and that pemphigus acantholysis is probably not caused by a serine proteinase.
Effects of levamisole in Sézary syndrome. Apparent acceleration of disease.
2 patients with Sézary syndrome were treated with levamisole. Both patients had clinical and hematological evidence of acceleration of their disease and ultimately died, although 1 patient had improvement in skin test reactivity. We suggest that levamisole be used with caution, if at all, in patients with T-lymphocyte malignancies.
[Pathogenesis of psoriasis].
Psoriasis is basically an excessive proliferation of the epiderm. This state results mainly from an imbalance in the cyclical nucleotides linked mainly to anomalies of the keratinocyte membranes. The membrane change is due to antibodies whose production may be dependent upon a deficit of a T-lymphocyte sub-population. This deficit may be considered the result of the penetration of virus agent with the help of multiple genetic factors. The various link of this pathogenic chain may be modified by numerous external factors which, by causing a worsening in a pre-existing imbalance, brings about the appearance of lesions.
Status report of 376 mycosis fungoides patients at 4 years: Mycosis Fungoides Cooperative Group.
The frequency and prognostic importance of various characteristics of patients registered by the Mycosis Fungoides Cooperative Group between November 1974 and December 1977 are reported. Variables which were considered include demographic and historical factors, symptoms, extent of disease, and other physical findings. A staging system which is based on the extent of skin involvement and the number of nodal sites clinically involved is described. Finally, a description of therapeutic results to date for patients randomized into Mycosis Fungoides Cooperative Group protocols is presented.
Bilateral and symmetrical porencephaly in neonates revealed by computerized tomography.
Explore the source record for details and available documents.
Acute hemiplegia in children.
Explore the source record for details and available documents.
Management of necrotizing vasculitis with colchicine. Improvement in patients with cutaneous lesions and Behcet's syndrome.
Six patients with necrotizing vasculitis were treated with oral colchicine as part of an open study. Four patients with cutaneous vasculitis and normal levels of serum complement and one patient with vasculitis associated with Behcet's syndrome demonstrated clinical improvement while receiving colchicine. One patient with cryoglobulinemia, hypocomplementemia, and cutaneous vasculitis showed no response to colchicine therapy. In three patients, clinical improvement persisted after its withdrawal. Colchicine may be effective in controlling cutaneous necrotizing vasculitis and Behcet's syndrome through its effect on polymorphnuclear leukocyte function.