Search PubMed⌕ Search

Biomedical subjects

R M Donaldson

Publications and source records attributed to R M Donaldson.

At least 91 records · Page 5Linked to original sources
PubMed1979

Mobile gamma cameras and 99mTc-labelled phosphates in acute myocardial infarction.

99mTc-labelled phosphates (PyP, IDP and MDP) were compared for their usefulness for the diagnosis of myocardial infarction. The results indicated the superiority of 99mTc-labelled imidodiphosphonate over the other 99mTc-labelled phosphates. At the same time, two mobile gamma cameras were compared with respect to their instrumental characteristics and clinical versalitity and their advantages and disadvantages are reported.

Diphosphates↗
PubMed1979

Anomalous origin of the left anterior descending coronary artery from the pulmonary trunk.

An extremely rare congenital abnormality is reported in which the anterior descending branch of the left main coronary artery arises independently from the pulmonary trunk in a young patient who presented with unstable angina. Its clinical presentation, angiographic identification and surgical treatment are described. It appears to be a distinct entity with few of the features of the classical form of anomalous origin of the left main coronary artery.

Adult↗
PubMed1979

Ventricular pseudo-aneurysm demonstrated by multiple gated cardiac imaging.

The use of multiple gated cardiac imaging in the diagnosis of left ventricular pseudo-aneurysm is reported and the clinical and therapeutic implications are discussed. Complemented with myocardial perfusion imaging, it is the method of choice for screening patients following infarction or chest trauma who may develop this potentially treatable complication of myocardial necrosis.

Heart Aneurysm↗
PubMed1978

Cardiovascular nuclear medicine and intensive care.

The clinical application of cardiovascular nuclear imaging techniques to intensive care medicine holds great promise for improved non-invasive assessment of the patient. With the development of new radiopharmaceutical agents and better instrument resolution, it is now possible to provide quantitative information concerning myocardial perfusion, acute myocardial ischaemia, left ventricular function, thromboembolic pulmonary disease and analysis of the patient's respiratory function. The patient can be studied during various phases of his disease, with these techniques furnishing objective guidelines of the therapy and prognosis.

Coronary Disease↗
PubMed1978

Results of aortocoronary bypass operations. Follow-up in 343 patients.

Three hundred and forty-three patients who had aortocoronary bypass graft operations for disabling angina were followed up for from 6 months to 5 years (average 2 years). 80 per cent had multiple grafts and 20 per cent had additional endarterectomy. The overall mortality within one month of operation was 5 per cent, and in those who had vein graft procedures only was 4 per cent. 11 per cent had a postoperative myocardial infarction (6% perioperative) and there were 3 per cent late deaths. At 3 years 90 per cent are surviving. 80 per cent are asymptomatic without treatment. The mean angina grade was 0.3 at the latest follow-up, compared with 2.5 before operation; maximum exercise tolerance was also significantly improved (P less than 0.001). When angina recurred, it did so in 80 per cent of the cases within 12 months of operation and was usually attributable to inadequate revascularisation. Ventricular function as assessed by preoperative ventriculography was the factor most clearly related to survival rate and the early excellent results of coronary bypass operations seem to be maintained up to 5 years. It is, therefore, reasonable to continue to advise operation if only for relief of angina.

Adult↗
PubMed1978

Effect of cimetidine on intrinsic factor and pepsin secretion in man.

The effect of cimetidine on gastric acid, pepsin, and intrinsic factor secretion was assessed in normal male subjects. Cimetidine (300 mg) completely inhibited acid, pepsin, and intrinsic factor concentration and output stimulated by betazole. In contrast, basal output of pepsin and intrinsic factor was not inhibited. We conclude that H2-receptor antagonists inhibit betazole stimulation of intrinsic factor output in addition to their well-known inhibition of acid secretion.

Adult↗
PubMed1978

Macromolecular secretion by isolated gastric mucosa: fundamental differences in pepsinogen and intrinsic factor secretion.

The secretion of pepsinogen and intrinsic factor (IF) in response to various known stimulators and inhibitors of gastric acid secretion was examined in isolated rabbit gastric mucosa maintained in organ culture. Acetylcholine (10(-8) M) stimulated stimulated both pepsinogen (P less than 0.01) and IF (P less than 0.01) secretion and this stimulation was blocked by atropine. Parasympatholytic agents did not alter unstimulated (basal) secretion of pepsinogen even at high concentrations (atropine, 10(-2) M or propanthelene bromide, 5 X 10(-3) M), however, at these concentrations basal IF secretion was abolished. Histamine (10(-4) and 10(-2) M) had no effect on pepsinogen secretion but stimulated IF secretion (P less than 0.001). Antagonism of H2 receptors by cimetidine reduced both basal and histamine-stimulated IF secretion, but pepsinogen secretion remained unaltered. Under the conditions of the above experiments the gastric mucosal surface was not exposed to HCl but was constantly buffered by culture medium at pH 7.4. When we applied 50 mN HCl to the mucosal surface of the biopsies, pepsinogen secretion doubled (P less than 0.001) but IF secretion was abolished. These studies have clearly documented that: (1) fundamental differences exist in the responses of pepsin and IF secreting cells; (2) H+ ions bathing the mucosal surface of the stomach may influence the results of experiments designed to examine the mechanisms of gastric mucosal macromolecular secretion.

Acetylcholine↗
PubMed1977

Changes in circulating transcobalamin II after injection of cyanocobalamin.

Since transcobalamin II is the plasma binder of vitamin B12(cobalamin) that mediates delivery of cobalamin to tissues, we measured circulating levels of transcobalamin II after intravenous injection unlabeled cyanocobalamin in 12 control subjects and, because the liver is a major source of transcobalamin II, in eight patients with decompensated cirrhosis. Thirty minutes after injection of cyanocobalamin (200 ng per kilogram of body weight), total transcobalamin II (unsaturated plus cobalamin bound) declined in all 20 subjects to levels that averaged (+/- S.E.) 53.5 +/- 4.6 per cent of initial values. Subsequently, unsaturated transcobalamin II rapidly increased so that by eight hours, total transcobalamin II approached preinjection levels. Rates of regeneration of transcobalamin II were similar in control subjects and patients with liver disease. Unlike total transcobalamin II, total transcobalamin I was unaltered by injection of cyanocobalamin. Moreover, addition of cyanocobalamin to plasma in vitro did not alter measurements of total transcobalamin II. The rapid response of circulating transcobalamin II to cyanocobalamin injection strongly supports a dynamic role for this polypeptide during transport of a relatively large load of cobalamin.

Adult↗
PubMed1976

Essential tremor, nystagmus and duodenal ulceration. A "new" dominantly inherited condition.

The familial occurrence of essential tremor combined with (congenital) nystagmus, duodenal ulceration and a narcolepsy-like sleep disturbance caused by an autosomal dominant gene with high penetrance and fairly uniform expressivity is reported in a family of Swedish-Finnish ancestry. Twelve of 17 affected family members had essential tremor which began between 30-40 years of age and which could be controlled temporarily by alcohol; this resulted in alcoholism in several affected individuals. The most severly affected persons showed cerebellar signs which may reflect a possible pathogenetic relationship of the syndrome to the genetic cerebellar atrophies. Nystagmus, observed in 12 of 17 affected family members (eight of whom were also affected with tremor) usually was congenital and accompanied by refractive errors. Duodenal ulcers occurred almost exclusively in individuals with the neurological syndrome, and preceded its onset in some cases. The ulcer disease therefore seems to be a component manifestation of the syndrome and is interpreted as a pleiotropic effect of the gene which also causes the nystagmus, tremor and sleep disturbance.

Adolescent↗
PubMed1976

Clinical experience with left main coronary artery stenosis.

We report the clinical features and the results of investigation and surgery in 20 patients with significant left main coronary artery stenosis. All had moderate to severe angina; 8 had pain at rest. Three had dyspnoea as a major symptom. The electrocardiogram was abnormal in 17, with evidence of previous myocardial infarction in 10. Of the 11 patients exercised, 8 developed chest pain. Nine patients had a normal left ventriculogram. At coronary angiography all patients had major disease elsewhere in addition to the left main coronary artery stenosis. There were no deaths or major complications associated with this investigation. One patient was unsuitable for surgery because of diffuse left ventricular hypokinesia, one had a fatal myocardial infarction while awaiting operation, and there was one preoperative death. Sixteen of the 17 surgical survivors are free from angina. There has been a significant improvement in the maximum exercise capacity in the 10 patients who had pre- and postoperative exercise tests.

Adult↗
PubMed1976

Surgical treatment of postinfarction left ventricular aneurysm in 32 patients.

Thirty-two patients with large postinfarction left ventricular aneurysms shown at operation to consist of fibrous tissue are reported. All had angina and/or breathlessness, and none had a history of embolism. Thirty were correctly diagnosed by left ventricular cineangiography. Two of the 3 patients with inferior and 1 with an anterior aneurysm had associated ventricular septal defects, and 3 patients with an anterior aneurysm had mitral regurgitation. All had major coronary arterial lesions and 68 per cent had double or triple vessel disease. The aneurysm was excised in all patients; in 15 this was combined with saphenous vein bypass grafting of coronary arteries supplying surviving myocardium, in 3 with closure of a ventricular septal defect, and in 3 with mitral annuloplasty or replacement. Operative mortality was 6-2 per cent, and 79 per cent of the survivors are asymptomatic with average follow-up period of 18 months after operation.

Adult↗