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Biomedical subjects

R Senior

Publications and source records attributed to R Senior.

12 recordsLinked to original sources

Quantitative 111In antimyosin antibody imaging to predict the age of myocardial infarction.

To establish whether quantitative 111In antimyosin uptake can be used to predict infarct age, we studied the heart-lung ratio in 107 images from 90 patients at various intervals following a Q-wave infarction. Imaging was performed 24 hours following 111In antimyosin injection. The HLR was measured as the ratio of the maximum counts in the infarcted myocardium to the adjacent lung background. The ratio ranged from 1.26 to 3.87, and declined with increasing infarct age. Infarcts were classified on the basis of age as type I (less than 3 days old), type II (less than 14 days), and type III (less than 90 days). True positive and false positive rates (TPR and FPR), and test-likelihood ratio calculations were performed for HLR thresholds ranging from 1 to 4, for the three infarct types. A FPR of 0% and likelihood ratio of infinity was obtained at a HLR threshold of 2.3 for type I infarcts (TPR 40.8%); at a HLR threshold of 2 for type II infarcts (TPR 50.6%), and a threshold of 1.8 for type III infarcts (TPR 52.6%). The likelihood of each infarct type can be estimated directly from the HLR for values below the above thresholds. These results show that quantitative 111In-antimyosin imaging may be used to predict infarct age.

Antibodies, Monoclonal

Right atrial thrombus migration during echocardiography: a case for urgent intervention.

A 65-year-old woman presented with increasing shortness of breath, chest pain and ST-T wave abnormalities on the electrocardiogram suggestive of unstable angina. Cross-sectional echocardiography performed to assess wall-motion abnormality and left ventricular function revealed a pedunculated right atrial thrombus prolapsing into the right ventricle which suddenly dislodged and migrated into the pulmonary circulation during the examination. A diagnosis of recurrent pulmonary thromboembolism was made, necessitating urgent pulmonary angiography with infusion of streptokinase. The patient made an uneventful recovery.

Aged

Effects of carvedilol on ventricular arrhythmias.

Carvedilol is a nonselective beta-blocker with alpha-mediated vasodilating properties that has been shown to be effective in systemic hypertension, stable angina, and congestive heart failure (CHF). In this study, we studied the effects of carvedilol on premature ventricular contractions (PVCs) in 65 patients undergoing treatment with carvedilol (12.5-50 mg b.i.d.) for 4-8 weeks. Twelve patients had hypertension, 41 had stable angina, and 12 had CHF. Holter monitoring for 24 h was performed before and after active carvedilol therapy. Median PVCs per 24 h decreased from 25.5 to 6.0 (p less than 0.001, n = 52). Reduction in PVC activity occurred in 77% of patients, and 23% of patients with multifocal PVCs changed their morphology to unifocal. Nonsustained ventricular tachycardia was present in four patients before treatment; this was abolished in all patients. R-on-T PVC was present in six patients; it decreased in five and increased in one. New ventricular tachycardia (less than 8 beats) occurred in two patients, but QT prolongation was not noted in these patients. An improvement in Lown's classification occurred in 50% of patients. However, in the CHF group, the improvement in Lown's criteria was observed in 73% of patients. Carvedilol does not appear to possess proarrhythmic effects, and chronic therapy reduces PVC activity in a wide range of patients. This property of carvedilol is complementary to its hypotensive and anti-ischemic effects. In the CHF group, the beneficial effects of carvedilol on left ventricular function and hemodynamics may combine with the improvement in PVC activity to produce a significant improvement in mortality.

Adrenergic beta-Antagonists

The Sheffield splint for controlled early mobilisation after rupture of the calcaneal tendon. A prospective, randomised comparison with plaster treatment.

Forty patients with acute complete rupture of the calcaneal tendon were managed conservatively and randomly allocated to treatment groups using either cast immobilisation for eight weeks, or cast immobilisation for three weeks, followed by controlled early mobilisation in a Sheffield splint. The splint is an ankle-foot orthosis which holds the ankle in 15 degrees of plantar flexion, but allows some movement at the metatarsophalangeal joints. It is removed to allow controlled movement during physiotherapy. Patients treated with the splint regained mobility significantly more quickly (p less than 0.001) and preferred the splint to the plaster cast. The range of dorsiflexion at the ankle improved more rapidly after treatment in the splint (p less than 0.001), and patients were able to return to normal activities sooner. Recovery of the power of plantar flexion was similar in the two treatment groups, and no patient had excessive lengthening of the tendon. One re-rupture occurred in each group.

Adult

Family therapy in general practice: views of referrers and clients.

Family therapy is being used in a variety of settings, including general practice. To assess the views as to the effectiveness and acceptability of a family therapy clinic in a north London surgery, questionnaires were given to general practitioners referring patients, and to clients. Replies were received from seven doctors and 20 clients, representing 11 families. There was a high level of satisfaction among general practitioners referring patients. The clinic proved to be highly acceptable for clients, with 90% agreeing that it was easier to attend a clinic at the practice than at a hospital; and only one patient thought that knowing the general practitioner worked in the practice made it harder to talk openly. Eighty per cent of patients felt the problem had improved at the time of follow up. Where the problem had not improved, 60% felt that they were dealing with it better. Almost all of the patients felt that the family therapy clinic should become a permanent part of local services. The family therapy clinic in general practice has been shown to be effective and popular with users of the service.

Adolescent

111In antimyosin antibody uptake is related to the age of myocardial infarction.

The intensity of 111In antimyosin uptake is related to the type (Q wave or non-Q wave), size, and location of an acute myocardial infarction. To determine whether the uptake intensity is also related to the infarct age, and to establish the time frame during which 111In antimyosin uptake occurs postinfarction, we studied a quantitative measure of uptake intensity, the heart-lung (HL) ratio, in 90 consecutive patients at various intervals following a Q wave infarction. Imaging was performed 24 hours following 111In antimyosin injection. Uptake of antimyosin could be demonstrated up to 154 days postinfarction. The HL ratio was measured as the ratio of the maximum counts in the infarcted myocardium to the adjacent lung background, and was 1.93 +/- 0.51 (mean +/- SD) overall. The ratio declined exponentially with increasing age of infarct. Using nonlinear regression analysis, 47% of the total variance of the HL ratio could be attributed to age alone (p less than 0.001). Sequential antimyosin imaging was performed in nine patients, with the first study between 4 and 15 days, the second between 50 to 100 days, and the third between 125 to 270 days after the onset of chest pain. The HL ratios were (mean +/- SD) 1.77 +/- 0.25 for scans between 4 and 15 days, 1.54 +/- 0.12 for scans between 50 and 100 days (p less than 0.02), and 1.42 +/- 0.16 (p less than 0.05) for scans between 125 to 270 days, further establishing the progressive reduction in 111In antimyosin uptake with age of myocardial infarction.

Adult

111In-antimyosin antibody imaging for detection of myocardial infarction: a quantitative approach.

Indium-111-antimyosin imaging has been shown to be a sensitive and specific method for detecting myocardial necrosis, but a quantitative method for interpretation of 111In-antimyosin planar images is lacking. A prospective study was performed in 114 patients with suspected acute myocardial infarction using planar 111In-antimyosin imaging. A ratio of maximum myocardial uptake counts (H) (9 X 9 pixels) over adjacent lung background (L), i.e. H/L ratio, was obtained from 24 and 48 h images. This value was compared with peak creatine kinase (CK) enzyme and left ventricular ejection fraction (LVEF). The patients were classified into groups based upon standard criteria for Q-wave acute myocardial infarction (Q-MI) (n = 50), non-Q-MI (n = 21), unstable angina (n = 15) and those with no evidence of MI or ischaemia (n = 28). The mean +/- S.D. H/L ratio in the Q-MI group was 2.28 +/- 0.50 (24 h, left anterior oblique, LAO, view) and was greater than the non-Q-MI group (1.98 +2- 0.30) (P less than 0.02). In patients with unstable angina (UA), seven had a high ratio (1.75 +/- 0.29) and eight had a lower ratio (1.29 +/- 0.07). In the group of patients without MI or UA, the ratio was 1.24 +/- 0.11 and this was significantly lower than the Q-MI and non-Q-MI groups and those patients with UA and positive 111In uptake (P less than 0.001, respectively). However, there was no significant difference between old MI and patients without evidence of MI or UA.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals

An echo-cardiographic (M-mode & 2D) analysis of thalassaemia major.

25 cases of thalassaemia major were studied by 2D and M-mode echocardiography. A significantly increased (p less than 0.001) mean value (100.8 +/- 27.37 msec, range 80 to 140 msec) of A2-E (early relaxation period) interval on M-mode was observed in thalassemia in comparison to mean level (82.6 +/- 5.7, range 60 to 100 msec) of control population. No significant differences were noted in FS % (fractional shortening) and EF% (ejection fraction) when compared to corresponding normal values respectively. Mean serum iron concentration (142.2 +/- 29.1 micrograms/dl, range 102 to 192 micrograms/dl) was significantly higher in thalassaemia as compared to normal population (mean 106.3 +/- 11.4 micrograms/dl, range 75 to 120 micrograms/dl). There was also a direct correlation between serum iron concentration and A2-E interval. 11 patients (44%) showed abnormal A2-E interval but only 3 patients (12%) showed abnormal percentage of FS and EF. It is therefore concluded that A2-E interval will help to detect early left ventricular dysfunction much before overt and irreversible heart failure becomes manifest and which will also help to optimise transfusion and chelation therapy.

Adolescent