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Biomedical subjects

M Simon

Publications and source records attributed to M Simon.

At least 541 records · Page 30Linked to original sources
PubMed1984

[Cytotoxic antibodies against lymphocytic antigens of cattle].

Typing reagents for the identification of bovine lymphocyte antigens were prepared. Sera obtained from cows killed in slaughterhouse were a good source of cytotoxic antibodies. Out of the 300 sera tested, 98 were cytotoxically active. The selected sera with a low reaction frequency were tested on a panel of 132 non-related animals. On the basis of the correlations between the sera, thirty of them could be included in four clusters. The sera within each cluster were closely associated; hence it can be assumed that a distinct specificity is represented by each of the clusters. It is suggested by correlation analysis and by the distribution of antigens in the population under study that the determined antigens fall within the same system and are genetically controlled by one or several closely associated loci.

Animals↗
PubMed1984

[Lichen ruber and diabetes mellitus--pathogenetic relations?].

In 177 patients with lichen ruber planus of the oral mucosa and in 177 sex- and age-matched healthy control subjects, the data of 24 laboratory parameters were studied prospectively. Abnormal glucose tolerance was observed in 30.1% of cases and in 11.9% of the control group (P less than or equal to 0.01%). Elevated serum cholesterin levels were found in 35.5% of the lichen ruber patients compared with 17.5% of the control population (P less than or equal to 0.1%). The coexistence of hyperglycemia and hypercholesterolemia was revealed in 11.9% of our lichen ruber patients and in 1.7% of the control group. Similar statistically significant differences in the mentioned parameters were seen in patients with sole skin involvement, as compared to the controls. The possible pathogenetic relationship between lichen ruber and diabetes mellitus is discussed, based on the results of this study.

Adult↗
PubMed1983

[Peripheral distribution of lymphocyte subpopulations in Basedow's disease. Decrease in suppressor T-lymphocytes].

The distribution of B- and T-lymphocyte subpopulations was studied in peripheral blood of 45 patients with untreated Graves' disease and 45 sex- and age-matched healthy controls. Blood samples were taken at the same hour in all subjects. The following tests were performed: HTLA and E (AET) for relative T-lymphocyte count, complement receptor (EAC) and surface immunoglobulins (IgS, IgG, IgM, IgA, kappa, lambda) for relative B-lymphocyte count. In 23 subjects of each group the subpopulations of T-lymphocytes were defined by their reactivity with monoclonal antibodies OKT8 (T-suppressor cells) and OKT4 (T-helper cells). Compared with the control group, patients with Graves' disease showed a decrease in the number of T-lymphocytes (HTLA: P less than 0.05: EAET: P less than 0.001) a decrease in T-suppressor cells (P less than 0.01), and no significant difference in B-lymphocytes and T-helper cells. Thus, the main lymphocyte characteristic in Graves' disease is a decrease in the relative value of T-cells, specifically affecting T-suppressor cells.

Adult↗
PubMed1983

[Immune phenomena in lichen ruber--an immunofluorescence study].

An immunofluorescence study was carried out in 40 patients suffering from lichen ruber of skin and/or mucous membranes. Autoantibodies in eluates of lymphoid cells directed against a hypothetical antigen of epidermal and/or dermal cells could not be demonstrated by means of the indirect immunofluorescence technique. However, direct immunofluorescence studies pointed to some interesting results hitherto not sufficiently paid attention.

Adult↗
PubMed1983

An optical micromethod for the determination of relative crystallisation rates of calcium oxalate in gels: method and preliminary results.

This paper describes a new, highly efficient micromethod for the determination of relative crystallisation rates of calcium oxalate (CaOx). Crystallisation is performed in the upper layer of a gel (bactoagar, agarose) which contains one component (oxalate) of the sparingly soluble salt. Precipitation is started by pipetting Ca++ containing solutions (in the presence and absence of crystallisation inhibitors) onto the gel. The process is followed quantitatively as a function of time by means of vertical light path photometry carrying out quasi-simultaneous multideterminations within a 50-fold multicuvette. The test volume is 0.1 ml. The method is suitable for large scale determinations. About 50 single crystallisation kinetics can be measured within 5-15 min. Testing three known inhibitors of CaOx crystal formation, relative inhibitory activities were obtained with standard errors of 1%-4%.

Calcium Oxalate↗
PubMed1983

Experimental hepatic iron overload in the baboon: results of a two-year study. Evolution of biological and morphologic hepatic parameters of iron overload.

Four baboons receiving intramuscular iron for 15 months were compared with two control baboons. From the overall two-year observation period the following data emerge: (1) The baboon is a suitable animal for obtaining a massive and chronic iron overload. Liver iron concentrations reached very high levels (ranging from 41.3 to 180.6 mumol/100 mg dry weight vs 1.7 +/- 0.5, mean +/- SEM, in controls), and a major liver iron overload (ie, with concentration values greater than or equal to 18) was present in all four animals for an average period of 16.5 months (range 14-19). (2) When compared with human hepatic iron-overload disorders, iron distribution was similar to that observed in secondary (transfusional) hepatic siderosis since iron deposits were found primarily in sinusoidal cells. However, a marked parenchymal siderosis was also obtained close to that observed in primary (genetic) siderosis. Iron toxicity was present biologically as indicated by an increase in serum transaminases. Histologically, a slight fibrosis was observed in the most heavily iron-overloaded baboon. On the whole, this study of subhuman primates brings new evidence that iron per se has only a minor hepatic damaging effect. It also suggests that the iron-overloaded baboon liver provides a promising tool for the study of liver cell disturbances in human iron overload.

Animals↗
PubMed1983

Analysis of a yeast nuclear gene involved in the maturation of mitochondrial pre-messenger RNA of the cytochrome oxidase subunit I.

We have analyzed the mitochondrial RNA of a yeast nuclear pet mutant with no cytochrome oxidase activity. The product of the gene affected in this mutant appears to be necessary for the correct maturation of the mitochondrial pre-mRNA of the cytochrome oxidase subunit I. It does not affect, however, the overall splicing of cytochrome b pre-mRNA or the intron excision of the 21S ribosomal RNA precursor. This gene has been isolated by genetic complementation in yeast, and its DNA sequence has been determined. It is transcribed, as detected by S1 mapping experiments, and could encode a protein of 436 amino acids.

Base Sequence↗
PubMed1983

Dimethyl sulphoxide (DMSO) induced serum hyperosmolality.

We describe a patient who received intravenous dimethyl sulphoxide (DMSO) (as part of an experimental protocol) to control increased intracranial pressure. The patient died of a brain abscess. She developed extreme serum hyperosmolality from the DMSO with the osmolality peaking at 717 mosmol/kg. DMSO may induce extreme serum hyperosmolality and should be utilized cautiously.

Adolescent↗
PubMed1983

An HLA-All association with the hemochromatosis allele?

Two hundred and seventy-four patients with hemochromatosis and 1005 controls were HLA-typed, and HLA haplotypes were determined for 163 patients and 123 controls. The increased frequency of antigen A3 and haplotypes A3, B7 and A3, B14 in patients with hemochromatosis was confirmed. After correction for the space taken up by A3, a significant increase in All was found. This increase could not be explained by cross reaction between A3 and All. All showed a phenotype association and a haplotype link with Bw35. The genetic significance of this increased All frequency is discussed.

Alleles↗
PubMed1983

Direct homocysteine biosynthesis from O-succinylhomoserine in Escherichia coli: an alternate pathway that bypasses cystathionine.

Mutations were found which enable Escherichia coli K-12 to form homocysteine in the absence of cystathionase. The formation of homocysteine in the mutant strains required cystathionine gamma-synthetase, the metB gene product, but bypassed the normal intermediate cystathionine. It is concluded that cystathionine gamma-synthetase catalyzes the formation of homocysteine directly from O-succinylhomoserine and an as-yet-unidentified sulfur donor. The mutation apparently causes the formation of this sulfur donor and has been named metQ. The expression of the metQ gene is under catabolite repression.

Carbon-Oxygen Lyases↗
PubMed1983

DNA sequence adjacent to flagellar genes and evolution of flagellar-phase variation.

A variety of factors, including phase variation, are involved in the regulation of flagellin gene expression in Salmonella sp. Flagellar-phase variation refers to the alternate expression of two different flagellin genes, H1 and H2. Site-specific inversion of a DNA segment adjacent to the H2 gene is responsible for switching expression. The segment includes the H2 promoter as well as the hin gene, which is required to mediate the inversion. Sequences in this region have homology with the corresponding sequences adjacent to the H1 flagellin gene in Salmonella sp. and the hag flagellin gene in Escherichia coli. The hin gene has also been shown to be homologous to the gin gene, which is found on bacteriophage Mu. To understand gene expression and the origin of these relationships, we have compared the DNA sequence adjacent to all three flagellin genes. The sequence data suggest a mechanism for the evolution of the hin-H2 locus.

Amino Acid Sequence↗
PubMed1983

Preoperative localization of nonpalpable breast lesions using a wire marker and perforated mammographic grid.

Preoperative wire localization of mammographically identified nonpalpable breast lesions is facilitated by using a perforated mammographic compression plate. This device is used in conjunction with a self-retaining wire, and its use results in accurate placement of the wire-marker tip in close proximity to the mammographically suspicious lesion. In 39 of 47 lesions, the wire tip was within 1.0 cm of the lesion, and in 45 of 47 lesions, the wire tip was within 1.5 cm of the lesion.

Adult↗
PubMed1983

The diameter of the inferior vena cava and its implications for the use of vena caval filters.

Inferior vena caval diameters were measured in 65 patients with Kimray-Greenfield (KG) inferior vena caval filters. The measurements were made at the distal tips of the filter tines on postplacement radiographs. Magnification corrections were made using the filter tine lengths as references. The overall mean diameter was 20 mm, the range was 13 to 30 mm, and the standard deviation was 3 mm. Two cavae (3%) were more than 28 mm in diameter. A previous in vitro study has shown that in venae cavae of this size there is a significant risk of reduced clot-capturing ability with the KG filter and migration with the Mobin-Uddin filter. Thus it is important to evaluate vena caval diameter by cavography prior to filter placement.

Filtration↗