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Biomedical subjects

M Simon

Publications and source records attributed to M Simon.

At least 523 records · Page 29Linked to original sources
PubMed1984

[Precancerous conditions and carcinomas of the lower lip. Coincidence with leukoplakia and carcinomas of the oral cavity and larynx].

In a prospective study of 102 patients with pre-neoplasia and/or manifest squamous-cell carcinoma of the lower lip the synchronous occurrence of intra-oral, pharyngeal or laryngeal leukoplakia and carcinoma was assessed. There was a coincidence rate of almost 15% leukoplakias, including individual carcinomas. This high coincidence is probably due to a combination of various "risk profiles" in patients with threatened or manifest lower-lip cancer. Chronic exposure to sunlight, especially in the presence of a genetic disposition, is the most important risk factor in lower-lip cancer and its preceding stages, while chronic alcoholism and smoking abuse have little etiological significance.

Adult↗
PubMed1984

[HLA typing of patients with herpes simplex recidivans and postherpetic erythema exsudativum multiforme].

62 patients suffering from recurrent herpes simplex, with ten out of them showing postherpetic erythema multiforme, have been investigated with special reference to histocompatibility standardisation. In comparison with a control group (n = 170), our patients revealed a high and statistically significant level of HLA-B5 (p less than 0,01). Postherpetic erythema multiforme seems to be associated with HLA-A9.

Adult↗
PubMed1984

[Essential thrombocythemia. Clinical, biological study and developmental study of 61 cases].

The 61 observations of primary thrombocythemia described in this report represent approximately 15% of the cases of polycythemia vera recorded by the authors over the same 18-year period. The group includes 35 females and 26 males, with a mean age of 62. The disease is usually discovered on routine blood tests (half of cases), and more rarely because of hemorrhagic or thrombotic manifestations. Splenomegaly is found in one-third of cases. Platelet count is permanently above 800 X 10(9)/l (mean : 1 500 X 10(9)/l); mild hyperleukocytosis (mean : 16 X 10(9)/l) with predominant neutrophil polynuclears is usual but myelemia is not constant (28% of cases) and always very moderate; red cell parameters are normal in three-fourths of cases, while the remaining patients have anemia, either due to iron depletion or not. Reticulinic myelofibrosis, usually minimal, is found in 40% of cases. Medullary karyotype is always normal, without chromosome Ph1. Platelet functional abnormalities are not constant and do not correlate with the magnitude of thrombocythemia. 51 patients (84%) received myelosuppressive therapy, mainly by busulfan or radioactive phosphorus. Most deaths were due to intercurrent causes and only one patient developed acute leukemia. 71% of patients are alive at five years and subsequent decrease in the actuarial survival curve is very gradual.

Busulfan↗
PubMed1984

The iron status of Black subjects with amoebiasis.

Hepatic iron concentrations were measured in 60 Black patients who had died of amoebiasis. There were 18 infants and young children, 30 adult males and 12 adult females. The mean hepatic iron concentration in infants was normal (0,11% dry weight), while those in adult males and females were significantly raised (0,64% and 0,30% dry weight respectively). The figures for adults are somewhat higher than those previously found in Black subjects, suggesting that iron overload is more common in patients with amoebiasis than in the general population. The relevance of these findings to the pathogenesis of amoebiasis is not clear but the relationship may well not be a direct one, since hepatic iron stores were no larger in patients with liver abscesses than in subjects without.

Adult↗
PubMed1984

[Micro and macrophage function test in patients with lichen ruber planus].

Various micro- and macrophage functions were studied in vitro in 21 patients suffering from lichen ruber planus and in 100 healthy individuals. A slight impairment of chemotactic activity of microphages (12/21) and a reduced capacity of intracellular inactivation of microorganisms in both systems (14/21; 3/12) were found.

Adult↗
PubMed1984

Organization and processing of the mitochondrial oxi3/oli2 multigenic transcript in yeast.

In the present article, we confirm our previous proposal (Faye and Simon 1983a, b) that the oxi3 and oli2 genes belong to the same transcription unit. Furthermore, we have shown that a primary polycistronic transcript covers oxi3, aap1, oli2 and extends beyond URF2. Transcriptional analysis of this region revealed several cleavage points. The examination of the DNA sequence at and surrounding these cleavage points disclosed that some of them take place at or near specific sequences found also in other known multigenic transcripts. Two of the major cleavages involve the stem-loop structure of GC rich clusters. We discuss the possibility that some of these cleavage sites serve as post-transcriptional processing signals and may be necessary for the maturation of the precursor RNA.

Base Sequence↗
PubMed1984

Participation of membrane-associated proteins in the formation of the cross-linked envelope of the keratinocyte.

Cultured keratinocytes, like those in natural squamous epithelia, form submembranous protein envelopes cross-linked by cellular transglutaminase. During the cross-linking, the cytosolic protein involucrin becomes incorporated into the envelope and can no longer be extracted by detergents. We show here that when transglutaminase is activated in cultured keratinocytes, at least six other proteins also become nonextractable. In contrast to involucrin, these proteins are associated with membranes. Two of the proteins (210 and 195 kd) are differentiated products specific to the keratinocyte; like involucrin, they are absent from small keratinocytes and fibroblasts, but appear in larger keratinocytes during the course of their terminal differentiation. The other proteins that become nonextractable cannot be destined exclusively for envelope formation since they are also present in fibroblasts. Transglutaminase is used by the mature (large) keratinocyte to make a detergent-resistant envelope from what appears to be a mixture of differentiation-specific and nonspecific proteins, both membrane-bound and cytosolic.

Acyltransferases↗
PubMed1984

The T cell receptor beta chain genes are located on chromosome 6 in mice and chromosome 7 in humans.

Homologous clones that encode the beta chain of the T cell antigen receptor have been isolated recently from both murine and human cDNA libraries. These cDNA clones have been used in connection with interspecies hybrid cell lines to determine that the murine T cell receptor gene is located on chromosome 6 and the human gene on chromosome 7. In situ hybridization confirms these data and further localizes these genes to band B of chromosome 6 in the mouse and bands 7p13-21 in the human genome. The organization of the T cell antigen receptor J beta gene segments and C beta genes appears to be conserved, since very few intraspecies polymorphisms of restriction fragment length have been detected in either mouse or human DNA.

Animals↗
PubMed1984

Steps in processing of the mitochondrial cytochrome oxidase subunit I pre-mRNA affected by a nuclear mutation in yeast.

In Saccharomyces cerevisiae, the mitochondrial gene encoding the subunit I of cytochrome c oxidase (oxi-3 gene) is interrupted by intervening sequences. In this report, a nuclear mutation [referred to as mss51 in Faye, G. & Simon, M. (1983) Cell 32, 77-87] that specifically affects the processing of oxi-3 pre-mRNA was further characterized. DNA probes covering each oxi-3 exon-intron boundary were individually hybridized to wild-type and mutant mitochondrial RNA. By a technique relying on the S1 nuclease resistance or sensitivity of the RNA X DNA hybrids thereof, we have shown which site needs the MSS51 gene product to be cleaved. The mutation in the MSS51 gene gave rise to a complex pattern of splicing: the third intron was excised efficiently but the first two introns remained bracketed by their flanking exons. Further, the fourth and fifth introns were only partially split from their common exon and remained fused to their upstream and downstream flanking exon, respectively. Several plausible roles for the MSS51 gene product are discussed.

Base Sequence↗
PubMed1984

Transposon mutagenesis of marine Vibrio spp.

Coliphage P1 was used to transduce derivatives of transposons Tn5 and mini-Mu into marine Vibrio spp. Transposon Tn5 encoding tetracycline resistance (Tn5-132) was used to isolate mutants of Vibrio harveyi defective in genes for bioluminescence (lux). Insertion of transposon Tn5-132 into the lux gene region was demonstrated by intraspecific transduction with phage hv-1 and by Southern blot hybridization. Transposon mini-Mu, modified to specify tetracycline resistance, was employed to mutagenize genes for lateral flagella synthesis of Vibrio parahaemolyticus. Mini-Mu contains the lacZ structural gene, and transposition results in transcriptional fusion of Vibrio genes with the transposon lacZ gene. Thus, in these fusions, lacZ expression was proportional to the level of transcription of the target gene. Regulation of lateral flagella gene expression was studied in vivo by measuring beta-galactosidase activity, and conditions which activate transcription of these genes were identified. A method for gene cloning with transposon-induced mutations is discussed.

Coliphages↗
PubMed1984

Chlamydia trachomatis pneumonia in adults: radiographic appearance.

Radiographic findings in six adults with evidence of community-acquired Chlamydia trachomatis pneumonia were studied. Streaky infiltration, without evidence of consolidation, and multilobar involvement were characteristic. Radiographic features that distinguish this unique entity from other community-acquired pneumonias and from Chlamydia trachomatis pneumonia in infancy are also discussed.

Adult↗
PubMed1984

Subpopulations of T lymphocytes in peripheral blood and in skin lesions in lichen ruber planus.

Peripheral blood lymphocytes and different immunocompetent cells of the cutaneous inflammatory infiltrate were characterized by reactivity with monoclonal antibodies directed to surface antigens of T lymphocytes and Langerhans cells by means of the indirect immunofluorescence technique in 10 patients suffering from lichen ruber planus. In contrast to the controls (n = 10), lichen patients had a significantly reduced percentage of the suppressor/cytotoxic T cell subset in peripheral blood (p less than 0.002). At the dermoepidermal junction suppressor/cytotoxic T lymphocytes and Langerhans cells predominated. Some possible conclusions are discussed.

Adolescent↗