Search PubMed⌕ Search

Biomedical subjects

H J Testa

Publications and source records attributed to H J Testa.

At least 91 records · Page 5Linked to original sources
PubMed1977

123-Iodine: a new isotope for functional renal scanning.

The results are presented of functional renal scanning in 11 urological patients using 123-iodine labelled Hippuran--a new radiopharmaceutical. The 123-iodine isotope possesses distinct advantages over existing isotopes, permitting high resolution imaging whilst delivering a low integrated radiation dose. It is hoped that the expense of this cyclotron-produced isotope will not mitigate against full evaluation of its promising potential.

Adult↗
PubMed1977

Dynamic scintigraphy in clinical urology.

The technique of isotope renal scintigraphy using Technetium-99m labelled agents and a gamma camera system on-line to a digital computer is described. Its value in diagnosing renal space-occupying disease and renovascular abnormalities is emphasised. A method of measuring individual renal haemodynamics and the possible potential of such techniques are discussed. Radio-isotope studies are rapid, simple, non-invasive and non-toxic. They give information complementary to that from urography.

Adult↗
PubMed1975

The value of the radio-isotope hepatogram in the jaundiced patient.

The distinction between 'medical' and 'surgical' jaundice is often difficult due to the lack of specificity of biochemical liver function tests, and the difficulty in assessing hepatocellular function and biliary tract patency in the jaundiced patient. We present a noninvasive isotopic technique which gives reliable information on these parameters, resulting in a high degree of accuracy in the classification of jaundice. 131I Rose Bengal, which is handled by the liver like bromsulphthalein, is administered intravenously and count rates during hepatic uptake and biliary excretion are recorded over the liver, biliary tract and duodenum using a gamma camera/computer system, into which is built an electronic light pen, so that particular areas of interest can be studied. Blood clearance of the iostope is simultaneously measured, and from these data the T 1/2 of uptake, the plasma retention and the excretion quotient are determined. The results of the first 80 examinations show that by qualitative assessment of the uptake and excretory phases of the 'hepatogram' and by determination of the T 1/2 and excretion quotient, jaundice has been classified with an 86 per cent accuracy in cases where the diagnosis is not apparent from clinical and biochemical data. The T 1/2 of uptake correlates well with bromsulphthalein retention in the non-jaundiced patient, and when applied to patients with obstructive jaundice enables the progress of hepatocellular impairment with time to be studied, and its recovery after relief of the obstruction. Preliminary results suggest that the technique may also have applications in the study of biliary tract dynamics in patients with post-cholecystectomy syndromes and relapsing acute pancreatitis.

Biliary Tract↗
PubMed1975

Evaluation of a proposed index of myocardial blood flow in dogs.

An index of myocardial blood flow developed from studies with a computer and a mechanical circulatory model has been investigated in 18 dogs. An intravenous injection of 131I is used with external scintillation detection over the left ventricle and the lung. The index is given by the ratio of the half time of the downslope of the curve recorded from the left ventricle to that of the curve recorded from the lung. This index has been compared with that suggested by Mena et al in which the left ventricular half time is compared with the half time of the brain curve. The effect on these indices and on the clearance of 133Xe of clamping the anterior descending branch of the left coronary artery has been observed. Statistically significant differences in both indices and in Xenon clearance were seen to be induced by coronary artery clamping but there was overlap between the clamped and unclamped values. The method used for coronary clamping also affected the results.

Animals↗
PubMed1975

A computer model and a mechanical model of the circulation and their use in the evaluation of indices of myocardial blood flow.

Computer and mechanical models of the circulation have been made to study isotopic techniques of determining indices of myocardial blood flow. Parameters in the program and dimensions in the mechanical model have been scaled to represent the human circulation. Single rapid injections of 131I labelled human serum albumen were given into the venous line of the mechanical model and records obtained from collimated scintillation detectors positioned over the heart, lung and brain. Similar injections and recordings were simulated in the computer model. Two indices of myocardial flow have been studied. The first, described by Mena et al. is the ratio of the half time of the downslope of the left ventricular curve to the half time of the downslope of the brain curve. This index distinguished myocardial flows of 0,5% and 10% of total cardiac output but was also affected by changes in cerebral flow. A new index is proposed in which the half time of the left ventricular curve downslope is related to the half time of the downslope of the lung curve. This index can distinguish myocardial flows of 0,5% and 10% total flow but is not affected by changes in cerebral flow.

Blood Circulation↗
PubMed1973

An evaluation of 75 Se selenomethionine scanning as a test of pancreatic function compared with the secretin-pancreozymin test.

The uptake of (75)Se Selenomethionine by the pancreas has been evaluated in 102 patients and compared with the secretin-pancreozymin test of pancreatic function. In groups of patients with chronic pancreatitis and cancer of the pancreas abnormal scans closely parallel the diminished exocrine secretion, especially bicarbonate output, following a submaximal dose of secretin. Thirty per cent of the group with no pancreatic abnormality have abnormal scans, though the secretinpancreozymin test is normal. Though a normal scan excludes the presence of chronic pancreatitis and cancer of the pancreas with a probability greater than 90%, an abnormal scan is found so frequently in normal subjects that it does not provide a reliable index of impaired pancreatic function.

Bicarbonates↗
PubMed1970

Experiences with data processing to separate the images in pancreatic scanning.

In many subjects, overlap of the image of the pancreas by the liver image makes clear delineation of the pancreas uncertain. A dual isotope technique was evolved with a ratio substract system. Experiments in vitro with a phantom liver and pancreas successfully erased the liver image from the final printout. In vivo, however, the results were in many cases unsatisfactory. A detailed statistical analysis of the data has provided an explanation for these differences.

Computers↗