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Biomedical subjects

J Thomas

Publications and source records attributed to J Thomas.

At least 829 records · Page 46Linked to original sources
PubMed1977

Aspirin intolerance--a review.

1. Association of bronchial asthma, nasal pathology and intolerance to aspirin is a unique syndrome. Aspirin-induced prolongation of bleeding time, and a tendency for diabetes, may exist with it. 2. The syndrome occurs most often in the middle-aged female. 3. Progression of asthma and nasal polyposis is not prevented by avoidance of aspirin. 4. Salicylates other than aspirin are well tolerated but cross-reactivity with other analgesics, and with tartrazine, may occur. 5. The underlying mechanism is unknown. An immunologic basic is most unlikely.

Adolescent↗
PubMed1977

Personality pattern of patients with chronic gastric ulcer. Study of neuroticism and extroversion in a gastric ulcer and a control population.

Forty-four patients with chronic gastric ulcer were compared with a control group matched for age, sex, and place of residence. The personality pattern was studied by the Eysenck Personality Inventory and personality assessed in terms of neuroticism and extroversion. The relevance of social class was also studied. The gastric ulcer population did not differ from the control group except among the male population, in which the gastric ulcer population was significantly more neurotic and less extroverted than their controls.

Adult↗
PubMed1976

Pathway of nitrogen metabolism after fixation of 13N-labeled nitrogen gas by the cyanobacterium, Anabaena cylindrica.

Methods have been developed for identifying the pathway of assimilation of N2-derived nitrogen. The products of fixation of 13N-labeled nitrogen gas ([13N]N2), and the distribution of 13N within glutamine, were determined after short periods of labeling (approximately 1 to 120 s) and also in pulse-chase experiments. Ammonia, the amide nitrogen of glutamine, and the alpha-amino nitrogen of glutamate, in that order, were the first observed products of fixation of N2 by the cyanobacterium (blue-green alga), Anabaena cylindrica. This sequence of the formation of nitrogenous products was confirmed by the use of inhibitors. The presence of 1 mM methionine sulfoximine permitted continued formation of 13NH3, while virtually preventing 13N-labeling of amino acids. In the presence of 1 mM azaserine, glutamine was labeled, but not other amino acids. Our observations demonstrate unequivocally that N2-derived nitrogen fixed by this organism is metabolized initially by the glutamine synthetase/glutamate synthase pathway.

Cyanobacteria↗
PubMed1976

Plasma protein binding and placental transfer of bupivacaine.

The maternal venous and umbilical venous plasma concentrations of bupivacaine were determined at delivery following epidural administration of the drug to 31 women in labor. In each case the umbilical venous plasma concentration of bupivacaine was lower than the maternal venous plasma concentration. There was no significant difference between the concentration of unbound bupivacaine in umbilical venous and maternal venous plasma at delivery. The difference in umbilical and maternal plasma concentrations of bupivacaine appears to be a consequence of greater bupivacaine binding to maternal than to fetal total plasma protein. The intersubject variation of the ratio of bupivacaine concentration in fetal plasma/bupivacaine concentration in maternal plasma was found to be related to individual variation in the extent of protein binding of bupivacaine in maternal and umbilical plasma and correlated positively with the variation of the ratio of total protein concentration in umbilical and maternal plasma.

Blood Proteins↗
PubMed1976

Inhibition of intestinal uptake of amino acids by unconjugated bile salt.

The unconjugated bile salt, sodium deoxycholate, at a concentration of 0.5 mM was shown to inhibit the intestinal uptake of the amino acids L-glycine, L-leucine, L-proline, L-lysine and L-tyrosine in rats in vitro. This effect was acutely reversible except for the basis amino acid L-lysine and is therefore not simply due to tissue damage. These results, and the recent finding that sodium deoxycholate inhibits intestinal absorption of amino acids in vivo, suggest that impaired intestinal amino acid transport may contribute to hypoproteinaemia in patients with bacterial overgrowth in the upper small intestine in whom deoxycholate is present in the small intestinal lumen in excessive concentrations.

Amino Acids↗
PubMed1976

The effect of end-stage renal failure and haemodialysis on the elimination kinetics of sotalol.

A single oral dose of sotalol (160 mg) was administered to control subjects with normal renal function and patients with chronic renal failure in the interdialysis period to estimate the elimination kinetics of the drug. Sotalol concentrations in body fluids were measured fluorimetrically using a modified Garrett and Schnelle (1971) method. Mean plasma half-life (T 1/2) was approximately 5 h in normals, 42 h in patients off-dialysis. During haemodialysis the mean plasma half-time was on the average 7 hours. Comulative urinary excretion of the drug was considerably lower in the patient group: 9% of the dose in 48 h as opposed to 61% in normals. Comparison of sotalol concentrations in plasma versus ultrafiltrate from the coil kidney indicates that the drug in vivo is negligible bound to plasma proteins in remal patients. The net-lowering effect of a 6 to 7 h haemodialysis on the plasma concentration decay line was by 20%. Post-dialysis plasma concentration data suggest that the rate at which sotalol returns to plasma from body tissues appears to be the rate-controlling factor in the elimination of sotalol by haemodialysis.

Adult↗
PubMed1976

Metabolism of etidocaine in man.

1. Etidocaine and eight metabolites excreted in urine of man have been detected by g.l.c. and investigated by g.l.c.-mass spectrometry. 2. Five metabolites have been identified by comparison with authentic compounds as 2-amino-2'-butyroxylidide, 2-N-ethylamino-2'-butyroxylidide, 2-N-propylamino-2'-butyroxylidide, 2.6-dimethylaniline and 4-hydroxy-2,6-dimethylaniline. 3. The structure of one of the remaining three metabolites is proposed to be 2-methyl-N3-(2,6-dimethylphenyl)-5-ethyl-4-imidazolidinone. 4. The amounts of etidocaine and seven of its metabolites excreted in a 48 h urine following epidural administration to a patient have been estimated. Approx. 31% of the dose was accounted for.

Acetanilides↗
PubMed1976

Effect of induced elevated plasma levels of homocystine and methionine in rats on collagen and elastin structures.

Young growing rats were intraperitoneally injected with mixtures of homocystine and methionine for several weeks. The growth of the animals was inhibited. After 3 weeks 25% of the rats died and isolation of tail tendon collagen and aorta elastin showed that these proteins were deficient in chemical cross-links. Seventy-five % of the rats survived further injections for another 3 weeks and isolated collagen and elastin were found to be normal in cross-linking. The variability in susceptibility of these rats to homocystine-methionine treatment is discussed in relationship to human homocystinuria. It is speculated that the variability is due to variability in in vivo homocysteine levels.

Animals↗