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Biomedical subjects

R D Thomas

Publications and source records attributed to R D Thomas.

122 records · Page 7Linked to original sources
PubMed1975

The effect of external potassium concentration on leucocyte cation transport in vitro.

1. Sodium and potassium transport rates in human leucocytes were measured in vitro at different external potassium concentrations. 2. At nominally zero external potassium concentrations, the ouabain-sensitive sodium efflux was reduced to less than 20% of its maximum value. There was evidence that under these conditions a ouabain-sensitive sodium-sodium exchange occurs. 3. Both total and ouabain-insensitive potassium influx increased with increasing external potassium concentration. The ouabain-sensitive potassium influx showed saturation. 4. Ouabain-insensitive potassium efflux was also stimulated by increasing the external potassium concentration, suggesting significant potassium-potassium exchange at physiological external potassium concentrations.

Biological Transport, Active↗
PubMed1974

Haemophilus influenzae meningitis in adults.

Haemophilus influenzae meningitis though common in childhood is rarely seen in the adult. During the past four years eight cases of H. influenzae meningitis have been seen in St. Thomas's Hospital and four of these were in patients over 20 years old. There was a possible predisposing condition in two patients. In each case there was difficulty in identification of the organism in the Gram-stained film of the cerebrospinal fluid deposit.

Adolescent↗
PubMed1974

Thyrotoxicosis and giant-cell arteritis.

In a retrospective survey we found that five (8.5%) out of 59 women with giant-cell arteritis had a history of thyrotoxicosis. This was significantly higher than in a control group of patients. Giant-cell arteritis and thyrotoxicosis occurred simultaneously in two cases. Knowledge of this association is of clinical use and is further evidence for an immunological basis for giant-cell arteritis.

Aged↗
PubMedDate not supplied

Stilbene estrogen produces higher levels of mitochondrial DNA adducts than nuclear DNA adducts in the target organ of cancer (liver) of male Sprague Dawley rats.

We have previously demonstrated that diethylstilbestrol is metabolized to diethylstilbestrol reactive metabolites by mitochondrial enzymes in vitro. In vitro, these reactive intermediates bind to mitochondrial DNA. Here we have investigated the in vivo formation of diethylstilbestrol adducts with mitochondrial DNA and the nature of mitochondrial DNA-diethylstilbestrol adducts. Diethylstilbestrol exposure to male rats produced several adducts in mitochondrial DNA of both kidney and liver. The total relative adduct levels were 7-fold higher in mitochondrial DNA than in nuclear DNA in the target organ of cancer (liver) of Sprague Dawley rats. The chromatographic mobility of mitochondrial DNA adducts formed in vivo were similar to that of dGMP-DES quinone adducts formed in vitro. These findings suggest that mitochondrial DNA appears more susceptible to formation of diethylstilbestrol adducts than nuclear DNA, and the results suggest that obstruction of replication and/or transcription of the mitochondrial genes by covalent modifications of the mitochondrial DNA by diethylstilbestrol may produce mitochondrial genomic instability in vivo and may provide an explanation for the carcinogenic effects of DES.

Animals↗
PubMedDate not supplied

Haemolysis following mitral valve repair.

We report the unusual occurrence of severe intra-vascular haemolysis following mitral valve repair. Mild to moderate mitral regurgitation was detected after repair, but severe haemolysis was the only indication for re-operation. Following prosthetic valve replacement there was an immediate cessation of haemolysis. We postulate that a small regurgitant jet directed against the teflon pledgets used in the repair was the reason for the haemolysis.

Aged↗
PubMedDate not supplied

Primary malignant lymphoma of the heart. Antemortem cytologic diagnosis.

A case of primary malignant lymphoma of the heart diagnosed cytologically is reported. The patient presented with pericardial tamponade and ventricular arrhythmias and developed rapidly progressive and intractable cardiac failure. Two-dimensional echo-cardiography, which demonstrated the pericardial effusion, showed progressive impairment of the left ventricular contraction. The pericardial fluid contained malignant lymphoid cells. Despite vigorous treatment and chemotherapy, the patient died within 15 days; postmortem examination showed malignant lymphoma confined to the myocardium.

Cytodiagnosis↗
PubMedDate not supplied

Is there a relationship between subclinical myocardial abnormalities, conduction defects and Ro/La antibodies in adults with systemic lupus erythematosus?

Thirty-three adult patients with systemic lupus erythematosus (SLE) were studied to determine whether there was an association between subclinical abnormalities of left ventricular function, conduction defects, and the presence of antibodies to Ro and/or La. Twelve patients had one or both of these antibodies. Conduction defects were present in 2, neither being currently positive for Ro or La antibody. There was no difference in abnormalities of left ventricular function between those with or without antibody. Valvular abnormalities were present in 11, 6 of whom had focal or diffuse thickening of one or more valves. Adults with SLE and anti-Ro and/or La antibody do not appear to be at particular risk of conduction defects. Subclinical left ventricular functional abnormalities were not associated with the presence of these antibodies.

Adult↗