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Biomedical subjects

T Martin

Publications and source records attributed to T Martin.

At least 271 records · Page 15Linked to original sources
PubMed1983

Relations between circulating levels of testosterone, 17 beta-estradiol, androstenedione, dehydroepiandrosterone sulfate, and androgenic receptor content of cytosol in benign prostatic hyperplasia.

Cytoplasmic androgen receptor content was determined in 26 patients with benign prostatic hyperplasia using methyltrienolone (R 1881) as the radioactive ligand. Their concentrations were compared with patient age, adenoma weight, and total circulating concentrations of testosterone, 17 beta-estradiol (17 beta-E2), androstenedione (A) and dehydroepiandrosterone sulfate (DHEA-S). Statistically significant inverse correlations were noted between adenoma weight and receptor content (p less than 0.05) and significant direct correlations between DHEA-S and receptor concentration (p less than 0.05), although the levels of this androgen were similar to those observed in a 'normal' population of the same age. The possible implications of these findings relative to the pathogenesis of the disease are discussed.

Aged↗
PubMed1982

Tularemia in Canada with a focus on Saskatchewan.

Although rare among humans in Canada, tularemia is often endemic in wildlife. The inhabitants of rural areas are especially likely to be exposed to the causative bacterium, Francisella tularensis, through trapping or through the bites of arthropods. Muskrats have replaced rabbits as the principal source of infection, as illustrated by a familial outbreak of oropharyngeal tularemia in Saskatchewan. In humans the disease has six distinct forms and can be asymptomatic, but it generally comes to medical attention as fever, persistent ulcers and enlarged lymph nodes. Serologic tests will confirm the diagnosis.Bien que la tularémie soit rare chez l'homme au Canada, elle existe souvent à l'état endémique parmi les animaux sauvages. Les habitants des régions rurales sont particuliérement susceptibles d'être exposés à l'agent étiologique, Francisella tularensis, lors du trappage ou par les morsures d'arthropodes. Le rat musqué a maintenant remplacé le lapin comme principale source d'infection, tel que l'illustre une poussée de tularémie oropharyngienne chez une famille de Saskatchewan. Chez l'humain la maladie prend six formes distinctes, et elle peut être asymptomatique, mais elle se présente généralement à l'attention du médecin comme une fièvre accompagnée d'ulcères persistants et d'une tuméfaction ganglionnaire. Les épreuves sérologiques confirment le diagnostic.

Agglutination Tests↗
PubMed1982

Functional mutants of yeast alcohol dehydrogenase.

Selection of petite strains of yeast (that is, strains unable to respire aerobically) on media containing allyl alcohol will result in enrichment for mutants at the ADC1 locus. This locus codes for the constitutive alcohol dehydrogenase, ADH-I, which is primarily responsible for the production of ethanol in yeast. The mutant enzymes are functional, and confer resistance to allyl alcohol on the cell by shifting the NAD-NADH balance in the direction of NADH. These mutants exhibit altered Km's for cofactor, substrate, or both, and often have altered Vmax's. In this paper, the methodology for obtaining these mutants and for determining the amino acid substitutions responsible for these changes is presented. Several new mutants have been at least approximately localized, and one, DB-AA3-N15, has been shown to be due to the substitution of an arginine for a tryptophan at position 54. This substitution would be expected, by analogy with the known tertiary structure of the horse liver alcohol dehydrogenase, to decrease the hydrophobic environment of the active site pocket. The substitution has a pronounced effect on the Km for ethanol, but far less on that for acetaldehyde. The current status of investigation of other classes of functional mutants of this enzyme, and the potential both for selection of useful variants of this molecule and for an increase understanding of its function are discussed.

Alcohol Oxidoreductases↗
PubMed1982

Family outbreak of yersiniosis.

Yersinia enterocolitica biotype 1, serotype O:21 was isolated from feces or rectal washings of three members of one family in northwestern Saskatchewan. The three isolates gave positive pathogenicity tests in guinea pigs with cultures grown at 22 degrees C as inoculum. All three cases showed clinical symptoms consistent with yersiniosis. All three cases had symptoms of diarrhea and abdominal pain, and two cases had recorded fever. In two cases, appendicitis was initially suspect. One case with ileitis and peritonitis was fatal. The environmental source of the infection was not found, but river water, milk, and person-to-person spread are discussed as possible sources of the infections. The need for microbiology laboratories to culture stool specimens specifically for Y. enterocolitica, using cold-enrichment techniques is emphasized. This family outbreak of yersiniosis provides further evidence that certain biotype 1 strains of Y. enterocolitica are pathogenic.

Adult↗
PubMed1982

Arming of mononuclear phagocytes by eosinophil peroxidase bound to Staphylococcus aureus.

When eosinophil peroxidase (EPO) was incubated with Staphylococcus aureus (staph) approximately 40% remained firmly bound to the bacteria as indicated by guaiacol assay. The staph-EPO complex was killed readily by concentrations of H2O2 and a halide that did not alter the viability of control (non-EPO-coated) organisms or organisms pretreated with another basic protein, protamine. This toxic effect was abolished by omitting either H2O2 or halide and was inhibited by azide, cyanide, or aminotriazole. Peroxidase activity was evident on the surface of the organism after ingestion by rabbit blood monocytes. The staph-EPO complex was killed at a greater rate by both rabbit blood monocytes and alveolar macrophages than were control organisms, an effect that did not appear to be secondary to improved phagocytosis. The peroxidase inhibitor azide inhibited the killing of staph-EPO by these mononuclear phagocytes without affecting the killing of control staphylococci; in the presence azide, the killing curve with staph-EPO returned to that seen with control organisms. Further, aerosolized EPO-coated organisms were cleared more rapidly from rat lung than were uncoated organisms or organisms pretreated with protamine. These findings suggest mononuclear phagocytes can utilize EPO bound to the surface of ingested microorganisms to enhance their microbicidal activity.

Animals↗
PubMed1980

Rapid, quantitative analysis of cell cycle stages of cold-sensitive derivatives of the Chinese hamster cell line CHO-K1.

Cell cycle parameters of two cold-sensitive Chinese hamster cell lines have been determined by flow cytometric analysis of cell populations stained with the DNA specific fluorochrome mithramycin. The most striking finding is a depletion of S phase cells, detectable as early as 12 h after a shift to the nonpermissive temperature of 30.0 degrees C and complete by 24 h following the shift. There is a substantial increase in the proportion of cells in the G1 phase of the cell cycle compared to wild type cells under identical conditions but, surprisingly, the proportion of cells having a G2/M DNA content is quite similar in the two populations. The proportion of tetraploid cells present in these populations is not sufficient to account for this observation. Reversibility of the cold-induced block was tested by returning cells held for three days at the nonpermissive temperature to the permissive temperature. Cells having a G1 content of DNA do reenter the S phase, beginning approximately 8 h after a return to the permissive temperature.

Animals↗
PubMed1980

[Inverted polypoid hamartoma of the rectum in a child].

Hamartomatos inverted polyps of the rectum were observed in a 12 years-old boy suffering from recurrent rectal discharges of mucus. Diagnosis was made on examination of rectal specimens obtained by local excisions and finally by recto-sigmoïdectomy, showing ectopic lobulated glandular structures deep to the muscularis mucosae. This histological aspect must be differentiated from adenocarcinoma, but in the paediatric age, prognosis depends on the degree of diffusion of the hamartomatous tissue, which may lead to extensive surgery such as recto-sigmoïdectomy. Whether this lesion is dysgenetic or acquired is discussed, and what relation can be presumed with solitary ulcer of the rectum is not clear.

Adolescent↗
PubMed1979

HnRNP core proteins: synthesis, turnover and intracellular distribution.

Our present data indicate that the Mr 34-40,000 polypeptides which are involved in the binding of a large fraction of hnRNA sequences, including mRNA, are for the most part metabolically stable species in mouse ascites tumor cells. An exception to this generalization is the smallest of 30S RNP core polypeptides, the Mr 34,000 protein, which has a relatively high turnover rate. The relationship of the various synthesis and degradation rates to the physiological state of mammalian cells remains to be determined, as does the pathway of assembly and disassembly of RNP substructures during re-utilization of the proteins and during their turnover. Immunofluorescent studies, which have confirmed the expected nucleoplasmic or euchromatic localization of the RNP core proteins, have also indicated that these species are stable during mitosis, at which time they are dispersed through the cell away from the condensed chromosomes. The proteins appear to relocate in the nucleus as soon as the nuclear envelope is reformed.

Animals↗