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Biomedical subjects

R M Thomson

Publications and source records attributed to R M Thomson.

16 recordsLinked to original sources
PubMed1998

Cytomegalovirus retinitis, human immunodeficiency virus antibody positivity and normal T helper cell numbers.

We describe a 46-year-old man in whom retinitis was diagnosed as his initial HIV and AIDS defining illness. A diagnosis of CMV infection was made based on the clinical appearance of the fundus and confirmed by DNA polymerase chain reaction (PCR) on his vitreous biopsy. His CD4+ T lymphocyte count at the time was 580 x 10(6)/l (16%) with a CD4:CD8 ration of 0.28. He had a splenectomy following trauma more than 20 years earlier. He responded very well to intravenous and oral ganciclovir and remains recurrence-free almost 2 years later. This case and others highlight two issues: (i) CMV retinitis in HIV positive is not confined to those with very low CD4+ T lymphocyte counts; (ii) previous splenectomy may have an impact on CD4+ cell numbers and function.

AIDS-Related Opportunistic Infections↗
PubMed1984

Lysosomal thyroid hormone 5'-deiodinase.

Lysosomes prepared from rat liver and kidney after loading with the detergent Triton WR-1339 show membrane-bound 5'-deiodinase activity with marked specificity for 3,3',5'-triiodothyronine (reverse T3), lesser activity with respect to thyroxine (T4) and almost none towards 3,3',5'-triiodothyronine (T3). The enzyme is thiol dependent and shows maximal catalysis at pH 7.2. As many of the states known to alter thyroid hormone levels also affect lysosomal function, inhibition of the lysosomal 5'-deiodinase leading to an increase in intracellular reverse T3 may be an initiating mechanism for thyroid hormone change.

Animals↗
PubMed1978

Repeated failure of nickel-containing prosthetic heart valves in a patient allergic to nickel.

Life-threatening peri-prosthetic incompetence developed with two successive nickel-containing mitral-valve prostheses in a patient allergic to nickel. Neither prosthesis had been incorporated satisfactorily. Her present nickel-free prosthesis seems to be satisfactory 22 months after insertion. Since allergy to nickel may have been involved in the failure of these prostheses, it is recommended that nickel-sensitive patients should be given nickel-free prostheses.

Female↗
PubMed1976

The renal handling of insulin and thyroid hormones in normal man.

1. The renal extraction of insulin and thyroid hormones T3 and T4 was studied in man by right renal vein catheterization. 2. The mean renal extraction of insulin was 0-46, suggesting that the right renal vein should be utilized in comparable studies. 3. No renal extraction of thyroid hormones was detected.

Adult↗
PubMed1976

Mitral valve replacement in the presence of severe pulmonary hypertension.

Thirty patients with severe preoperative pulmonary hypertension (pulmonary artery pressure range 90-165 mmHg, mean 118 mmHg) were reviewed following single mitral valve replacement, with prosthetic valves, within the last 10 years (1964-74). The early and late mortality for this group was no different from that of the total series of mitral valve replacements performed over the same period. Marked postoperative clinical improvement was accompanied by corresponding radiological and electrocardiographic changes. In addition there was a statistically highly significant haemodynamic improvement in the 21 survivors (mean survival time 5 1/2 years). At recatheterization the mean pulmonary artery pressure was 41-5%, the mean wedge pressure 46-3%, and the transpulmonary gradient (PAm-LAm) 36-1% of the preoperative values. It is concluded that gross pulmonary hypertension is not per se a contraindication to mitral valve replacement surgery.

Adult↗
PubMed1975

Tricuspid valve replacement: a five-year appraisal.

Organic disease of the tricuspid valve required surgery in 18% of all patients undergoing valve replacement over a five-year period. Differentiation of organic from functional disease is difficult and may be made only at open-heart surgery. The results of a series of 56 patients who underwent tricuspid valve replacement are presented; of these, 53 had organic disease. Operative mortality at the end of five years had fallen to 7% with significant clinical improvement in 79% of patients, a reduction in cardiothoracic ratio in 81%, and a low incidence of postoperative tricuspid incompetence.

Female↗
PubMed1975

Early results of heart valve replacement with the Björk-Shiley prosthesis.

The operation on and subsequent course of 88 patients with valve replacements using Björk-Shiley tilting disc prostheses has been reviewed in terms of mortality, clinical results, and valve function. The follow-up period varied between 6 months and 2 years. The hospital mortality was 17% and late mortality 8%. Of those who left hospital, 75% returned to full normal activity and required less (or no) drug therapy other than maintenance anticoagulation. There was one transient embolic episode. Significant intravascular haemolysis does not occur with this prosthesis.

Adult↗
PubMedDate not supplied

Early systemic hypertension after surgical closure of atrial septal defect.

The systemic haemodynamic changes occurring in the immediate post-operative period were examined in a series of patients undergoing closure of atrial septal defect (A.S.D.) and in a consecutive series of all patients undergoing open-heart surgery in this Unit. Significant systemic hypertension was observed in 47.5% of patients in the A.S.D. series. In an attempt to explain this finding, several other haemodynamic variables were examined in relation to the systemic blood pressure. There was no correlation between central venous pressure or blood loss and systemic blood pressure. However, there was an inverse correlation between blood balance and systolic and diastolic blood pressure at 4 hours after operation. The explantation of this finding is unclear but it may be due to the effects on atrial receptors of lower right atrial and pulmonary artery pressures following closure of the A.S.D. Although the post-operative systemic hypertension was transient in most cases, it may produce adverse effects in the early post-operative period and therefore treatment with hypotensive agents should be considered in severe cases.

Blood Volume↗
PubMedDate not supplied

Sinoatrial disorders, the "sick sinus" syndrome. Experience with implanted cardiac pacemakers.

The long term results of permanent pacemaker implantation in patients with disorders of the sinoatrial node and atrial conduction pathways were studied. In a consecutive series of 300 patients treated by pacemaker implantation, 68 ((22.3%) had sinoatrial disorders. Mean age of the group was 54 years (33-82 years); 37 were male, 31 female. Diagnosis was confirmed by serial electrocardiography with overdrive suppression of sinoatrial node function as indicated. Twenty-two patients presented with sinus bradycardia alone (Type I disorder) and 46 with bradycardia-tachycardia syndrome (Type II disorder) were completely controlled. of the 46 Type II patients, in 30 (65.2%) tachyarrhythmias were controlled by pacing alone and in 14 (30.4%) by pacing and antiarrhythmic drug therapy. Congestive cardiac failure was relieved in 80% and anginal pain in 70% of patients with rate control alone. Systemic embolisation did not recur after pacemaker implantation. The average duration of pacemaker therapy was 52 months (12-96 months). In this series, long term ventricular demand pacing proved beneficial in both types of sinoatrial disorders.

Adult↗
PubMedDate not supplied

Hypernatraemic dehydration following tricuspid valve replacement.

The development of abnormally high plasma sodium and plasma osmolality levels is described in 5 patients following open-heart surgery involving prosthetic replacement of the tricuspid valve. These biochemical abnormalities developed in the early post-operative period and were associated with an excessive diuresis during the first 3 to 4 days after operation. Biochemical correction required a prolonged, high volume intravenous water load, and was paralleled by progressive clinical improvement, notably in peripheral circulation, tissue turgor and cerebral function. Plasma sodium and osmolality levels and observed fluid balance in 20 patients undergoing similar surgical procedures for tricuspid valve lesions fail to show this hypernatraemic, hyperosmolar state, and indicate that the majority of such patients have a markedly positive observed fluid balance in the early post-operative period. These differences are statistically highly significant (p less than 0.001). Consideration of urine/plasma osmolality levels reveals a transient but highly significant impairment of renal concentration in the hypernatraemic patients (p less than 0.001).

Blood↗