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Biomedical subjects

A T Elliott

Publications and source records attributed to A T Elliott.

At least 55 records · Page 3Linked to original sources
PubMed1986

Treatment of angina pectoris with nifedipine and atenolol: efficacy and effect on cardiac function.

The antianginal effects of nifedipine 20 mg three times a day and atenolol 100 mg once a day singly and in combination were investigated in 16 patients with angina pectoris. The amount of work that could be done before angina and ST depression appeared was significantly increased by atenolol and the combination but not by nifedipine. At peak exercise the number of leads on a 16 point precordial electrocardiogram map that demonstrated greater than or equal to 1 mm ST segment depression was significantly reduced from a mean (SD) of 5.0 (0.4) on placebo to 3.7 (0.6), 2.8 (0.4), and 2.3 (0.7) on nifedipine, atenolol, and the combination respectively. Mean resting left ventricular ejection fraction, assessed by gated radionuclide ventriculography, did not change during any active treatment phase but increased significantly during exercise only on nifedipine and the combination. The nifedipine/atenolol combination was the most effective treatment, and the data suggest that nifedipine may be used to best advantage in combination with a beta blocker.

Angina Pectoris↗
PubMed1984

Gold 195m radionuclide ventriculography in the assessment of left ventricular performance in fit elderly men.

We investigated, by radionuclide ventriculography, left ventricular function in 10 fit elderly men and in 11 young volunteers. During exercise in the young subjects left ventricular ejection fraction (LVEF) rose from 63 +/- 3 to 73 +/- 1 (P less than 0.005) and end systolic volume (ESV) fell from 48 +/- 6 to 38 +/- 5 ml (P less than 0 +/- 0.005) but were unchanged in the elderly (57 +/- 3 to 55 +/- 3 and 57 +/- 6 to 64 +/- 7 ml, respectively (NS). End diastolic volume (EDV) did not change in either group; stroke volume rose significantly only in the younger subjects, cardiac output rose in both groups but less in the elderly (5 +/- 0.5 to 12 +/- 1 vs 6 +/- 0.5 to 18 +/- 11 min-1). We conclude that this data lend support to the hypothesis that increasing age is associated with reduced left ventricular contractile performance.

Aged↗
PubMed1983

A 195Hgm-195Aum generator for use in first-pass nuclear angiocardiography.

The development of a mercury-195m/gold-195m radionuclide generator system is described, together with the results of preliminary experiments in animals and in man. The daughter radionuclide has a half-life of 30.5 s with a principal gamma emission at 262 keV, ideal for use with the multicrystal camera but suitable also in conjunction with the Anger design. The half-life of the parent radionuclide is 40 h. The eluant in current use is 2.5 mM sodium cyanide, the column being stored under 2% sodium nitrate solution when not in use to prevent radiation damage. Generators capable of delivering 550 MBq of 195Aum in a 0.4 ml bolus have been used for first-pass nuclear angiocardiography, the half-life being long enough to permit administration via peripheral intravenous injection. The radiation dose associated with this radionuclide is much lower than that from conventional 99Tcm-labelled radiopharmaceuticals, permitting multiple sequential studies, even on children.

Animals↗
PubMed1982

Combined exercise radionuclide and hemodynamic evaluation of left ventricular aneurysmectomy.

Twelve patients were studied by rest and exercise radionuclide ventriculography following left ventricular aneurysmectomy (LVA). Left ventricular filling pressure (LVFP) was also measured. Nine patients had been studied pre-LVA at rest and exercise before and after isosorbide dinitrate (ISDN). Resting ejection fraction (LVEF) improved after LVA (p less than 0.25), but exercise LVEF did not. End-diastolic volume (EDV) and resting LVFP also fell after LVA (p less than 0.25 for EDV, p less than 0.05 for LVFP) and although exercise LVFP fell (p less than 0.02), the values were abnormal in all patients. Ejection fraction of contractile segment (EFCS) from the resting radionuclide study pre-LVA was related to resting LVEF post-LVA (r = 0.71 p less than 0.02), although postoperative LVEF could not be predicted from preoperative EFCS in individual patients. Deterioration in LVEF and LVFP from rest to exercise post-LVA occurred both in patients with single-vessel occlusion and in those with multivessel coronary disease, irrespective of whether or not revascularization had been performed. Thus LVA is effective in improving resting ventricular function; exercise performance may remain abnormal even in patients without residual coronary disease.

Adult↗
PubMed1982

Detection of human cancer in an animal model using radio-labelled tumour-associated monoclonal antibodies.

Monoclonal antibodies to epithelial-cell antigenic determinants, labelled with 123I and 125I, were administered parenterally to immunodeficient mice bearing human tumours derived from a human cancer cell line. Anterior, posterior and lateral radioscans of the body were taken with a gamma scintillation camera at various times from immediately to 65 days after injection. Visual displays of the images were processed by standard computer techniques. The model used a human colon-cancer cell line, HT29, and the monoclonal antibody, AUA1, which is specific to an epithelial proliferating antigen. Tumour detection was achieved in all the mice. The smallest tumour detectable appeared to be about 1 mm in diameter. The degree of antibody uptake in a tumour depended on its size and the blood supply of its surrounding tissues We believe that the technology and skills are now available for accurate radioimmunodetection of cancer in man.

Animals↗
PubMed1982

Factorial phase imaging: a new concept in the analysis of first-pass cardiac studies.

A method is described which offers an alternative to conventional Fourier phase/amplitude imaging for analysing representative LV cycles obtained from first-pass cardiac studies. The method involves applying factor analysis to the data and producing functional images of the first two factor loadings after polar transformation. The method corrects for cycle asymmetries which produce anomalies in the Fourier images. For 88 studies the method provides greater uniformity among normal phase images while retaining, or even enhancing, abnormalities. Small differences between amplitude images produced by the two methods do not appear to be important.

Fourier Analysis↗
PubMed1981

A multiaperture collimator for use at 511 keV.

Positron-emitting radionuclides are being used more and more in nuclear medicine. This paper describes a high energy collimator suitable for imaging at 511 keV, the energy emitted by these radionuclides, for use with the Baird Corporation's System 77.

Gamma Rays↗
PubMed1979

Cardiac emission tomography in patients using 201thallium. A new technique for perfusion scintigraphy.

The distribution of 201thallium (Tl) in the myocardium has been studied by the new technique of emission tomography, and compared with standard gamma camera images in 5 patients. Tomographic imaging was carried out using a dual-detector scanner operated under the single-photon technique. Initial results have been promising, with visualisation of resting perfusion defects in patients with recent infarction and those with ventricular aneurysms. Emission tomography has also been performed at exercise, and has shown tracer deficits in the distribution of significant coronary stenoses. This new approach to myocardial perfusion scintigraphy may lead to improved sensitivity for detecting apical and inferior wall abnormalities by providing depth information not available from a conventional two-dimensional image.

Coronary Disease↗
PubMed1979

Whole body elemental composition during drug treatment of rheumatoid arthritis: a preliminary study.

Thirty-two female patients with rheumatoid arthritis were divided into 3 groups and treated for 6 months with prednisolone, depot tetracosactrin, or indomethacin. Their whole body content of calcium, phosphorus, and nitrogen was measured before and after 3 and 6 months' treatment by in-vivo neutron activation analysis. No significant changes in these body elements were observed as a result of the treatments. The average amounts of calcium, phosphorus, and nitrogen were lower than normal in these patients, a finding consistent with the frequent observation of osteoporosis and muscle wasting in rheumatoid arthritis.

Adult↗