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Biomedical subjects

J Thompson

Publications and source records attributed to J Thompson.

At least 685 records · Page 38Linked to original sources
PubMed1982

Thirteen primary adenocarcinomas of the ileum and appendix: a case report.

Adenocarcinomas of the ileum and appendix are uncommon. Multiple synchronous adenocarcinomas of the small bowel without carcinoid features are even more unusual, with only seven reported cases in the literature. The radiologic and pathologic findings are reported in a case with 13 separate, well-documented synchronous primary adenocarcinomas of the ileum and appendix. The value of the double-contrast small bowel enema is emphasized.

Adenocarcinoma↗
PubMed1982

Sleep architecture and REM sleep measures in prepubertal children with major depression: a controlled study.

We performed a three-night polysomnographic study of 54 rigorously assessed, drug free, prepubertal children who fit unmodified Research Diagnostic Criteria for major depressive disorder, and two groups of nondepressed controls (25 with emotional disorders and 11 who were normal). The groups did not differ polysomnographically, even though a high proportion of depressives and neurotics reported sleep disturbance in structured interviews. Sleep stage data do not appear to differentiate children with prepubertal major depressive disorders from nondepressed neurotic or normal children. Other psychobiologic findings in prepubertal depressives together with marked age effects on polysomnographic correlates of adult major depressive disorders suggest the hypothesis that polysomnographic abnormalities in adult major depressives are secondary to an interaction between depression and age.

Adult↗
PubMed1982

The role of bacterial adherence in the pathogenesis of infective endocarditis.

Bacterial adherence as a result of specific surface properties may be a contributory factor in the pathogenesis of bacterial endocarditis giving certain types of bacteria a selective advantage to cause this disease. Adherence could interact with other pathogenetic mechanisms, and this interaction could promote or hamper the development of endocarditis. Dextran production by streptococci, the activation of the clotting system by monocyte tissue thromboplastin, and phagocytic removal of bacteria from the vegetational surface by granulocytes and monocytes are examples of interacting mechanisms that could contribute to the pathogenesis of bacterial endocarditis.

Adhesiveness↗
PubMed1982

The mode of action of berninamycin and mechanism of resistance in the producing organism, Streptomyces bernensis.

The mode of action of berninamycin on bacterial protein synthesis is related to that of thiostrepton, a dissimilar compound. Both antibiotics bind to the complex of 23S RNA with protein L11 and both affect various functions of the ribosomal A site. Also, Streptomyces bernensis and Streptomyces azureus (which, respectively, produce berninamycin and thiostrepton) possess similar ribosomal RNA methylases capable of rendering ribosomes resistant to these compounds. Resistance involves specific pentose-methylation of 23S ribosomal RNA.

Anti-Bacterial Agents↗
PubMed1982

Role of granulocytes in experimental Streptococcus sanguis endocarditis.

We investigated the role of granulocytes during the induction and course of experimental Streptococcus sanguis endocarditis in rabbits by depleting blood granulocytes with nitrogen mustard. The induction of the endocarditis was not influenced by granulocytopenia: the 50% infectious dose was 5.4 X 10(4) colony-forming units in normal and granulocytopenic rabbits. However, granulocytopenia influenced the curse of the endocarditis, as shown by a significant increase in the number of colony-forming units per gram of vegetation (P less than 0.02) from 24 to 72 h after the injection of 10(5) colony-forming units of S. sanguis. This rise did not occur in the control rabbits. Furthermore, bacteremia was significantly higher in the granulocytopenic rabbits (P less than 0.05) during the first 48 h compared with the control rabbits. This was not because of altered clearance of the streptococcus inoculum or seeding of streptococci from extracardiac bacterial foci. We concluded that granulocytes have no measurable effect on the induction of S. sanguis endocarditis, but during the course of the endocarditis, granulocytes keep the endocardial infection in check.

Agranulocytosis↗
PubMed1982

Biochemical characterization of resistance determinants cloned from antibiotic-producing streptomycetes.

Determinants of antibiotic resistance have been cloned from four antibiotic-producing streptomycetes into Streptomyces lividans. Biochemical analyses of resistant clones revealed the presence of enzymes that had previously been characterized as likely resistance determinants in the producing organisms. These included: 23S rRNA methylases from S. azureus and S. erythreus, which confer resistance to thiostrepton and erythromycin, respectively; viomycin phosphotransferase from S. vinaceus; and aminoglycoside phosphotransferase and acetyltransferase from the neomycin producer S. fradiae. In general, the levels of antibiotic resistance of the clones were similar to those of the producing organisms. Although the two aminoglycoside-modifying enzymes from S. fradiae could independently confer only low-level resistance to neomycin, the presence of both enzymes in the same strain resulted in a level of resistance comparable with that of the producing organism.

Acetyltransferases↗
PubMed1982

Novel phosphoenolpyruvate-dependent futile cycle in Streptococcus lactis: 2-deoxy-D-glucose uncouples energy production from growth.

The addition of 2-deoxy-D-glucose to cultures of Streptococcus lactis 133 that were growing exponentially on sucrose or lactose reduced the growth rate by ca. 95%. Inhibition did not occur with glucose or mannose as the growth sugar. The reduction in growth rate was concomitant with rapid accumulation of the analog in phosphorylated form (2-deoxy-D-glucose 6-phosphate) via the phosphoenolpyruvate-dependent mannose:phosphotransferase system. Within 5 min the intracellular 2-deoxy-D-glucose 6-phosphate concentration reached a steady-state level of greater than 100 mM. After maximum accumulation of the sugar phosphate, the rate of sucrose metabolism (glycolysis) decreased by only 30%, but the cells were depleted of fructose-1,6-diphosphate. The addition of glucose to 2-deoxy-D-glucose 6-phosphate preloaded cells caused expulsion of 2-deoxy-D-glucose and a resumption of normal growth. S. lactis 133 contained an intracellular Mg2+-dependent, fluoride-sensitive phosphatase which hydrolyzed 2-deoxy-D-glucose 6-phosphate (and glucose 6-phosphate) to free sugar and inorganic phosphate. Because of continued dephosphorylation and efflux of the non-metabolizable analog, the maintenance of the intracellular 2-deoxy-D-glucose 6-phosphate pool during growth stasis was dependent upon continued glycolysis. This steady-state condition represented a dynamic equilibrium of: (i) phosphoenolpyruvate-dependent accumulation of 2-deoxy-D-glucose 6-phosphate, (ii) intracellular dephosphorylation, and (iii) efflux of free 2-deoxy-D-glucose. This sequence of events constitutes a futile cycle which promotes the dissipation of phosphoenolpyruvate. We conclude that 2-deoxy-D-glucose functions as an uncoupler by dissociating energy production from growth in S. lactis 133.

Deoxy Sugars↗
PubMed1982

Combined hereditary deficiency of the sixth component of complement and factor VIII coagulant activity in a Dutch family.

Prompted by previous observations of defective blood clotting in rabbits deficient in the sixth component of complement (C6), and the discovery of a patient with both C6 and factor VIII deficiency, an evaluation was made of the haemostatic functions in this individual and his family members. The family contained three members homozygous for C6 deficiency (C6D); two of them were deficient also in factor VIII. In addition, one other member of the family was only deficient in factor VIII. The only C6D member without haemophilia A had a normal recalcification time without clinical symptoms of a bleeding disorder. Reconstitution of factor VIII and C6 deficient plasma from the various members of the family in this study with purified human C6 did not result in a change in the recalcification time. The results obtained from this study also indicate that there is no linkage between the inheritance of C6 and factor VIII.

Adult↗
PubMed1982

An improved ultrafiltration method for determining free testosterone in serum.

In this method, we use the Amicon MPS-1 centrifugal ultrafiltration device and the YMB membrane in measuring free testosterone in serum. Two independent assays are combined: total testosterone and the ultrafiltrable fraction of added [3H]testosterone. The unbound fraction is determined in 0.15-0.5 mL ultrafiltrates of 0.6 to 1 mL of variably diluted serum that has been equilibrated with [3H]testosterone at 37 degrees C. The assay is rapid (less than 1 h), practicable (requires 0.6 mL of serum), and reproducible (CV 3.2% within assay, 3.9% between assays). Accuracy was evaluated as the fraction of free testosterone in the ultrafiltrate of dialyzed serum vs that in a prior dialysate; they were the same confirming the validity of the free testosterone measurement. Samples from ostensibly healthy men and women and from hirsute and pregnant women gave results that agreed with those obtained by equilibrium dialysis. Total testosterone concentrations for normal and hirsute women showed considerable overlap, but data on free testosterone concentrations in these populations were better resolved.

Adult↗