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Biomedical subjects

P Steele

Publications and source records attributed to P Steele.

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

Pituitary-dependent hyperadrenocorticism in a cat.

Pituitary-dependent hyperadrenocorticism was diagnosed in a 9-year-old, male castrated cat that had polyuria, polyphagia, pendulous abdomen, truncal hair loss, congestive heart failure, and insulin-resistant diabetes mellitus. Results of pituitary-adrenal function testing revealed inadequate serum cortisol suppression following dexamethasone administration, exaggerated serum cortisol responses after exogenous ACTH stimulation, and high plasma ACTH concentrations. The pathologic findings of bilateral adrenocortical hyperplasia and a pituitary adenoma that immunostained well for ACTH-related peptides confirmed pituitary-dependent hyperadrenocorticism.

Adenoma, Chromophobe↗
PubMed1986

A study of nutritional myopathy in weaner sheep.

The effectiveness of various treatments upon, and pathological and biochemical changes in, ovine weaner nutritional myopathy were observed. Clinical myopathy was already apparent in the sheep at the start of the study, and they were fed decreasing amounts of a ration containing low levels of selenium and alpha-tocopherol, and periodically deprived of water. In spite of this management there was a spontaneous remission of the clinical myopathy in the sheep, but a subclinical myopathy was identified in some of the sheep at the end of the trail. The conclusions were that the myopathy was not caused by a low dietary intake of selenium and/or alpha-tocopherol alone, that alpha-tocopherol was involved in the aetiology, that alpha-tocopherol was completely effective and selenium possibly partially effective in treating it, and that the condition may be a Type II muscle fibre disease. Data on plasma creatine phosphokinase and erythrocyte glutathione peroxidase activities, and terminal liver selenium and alpha-tocopherol concentrations are presented, and their roles in the diagnosis of ovine weaner nutritional myopathy discussed.

Animals↗
PubMed1985

Short-term culture of pediatric brain tumors.

Three short-term culture systems were applied to ten pediatric brain tumors and two samples each of normal child's brain and fetal brain. Growth in monolayer occurred in nine of the ten tumors but normal child's brain also produced cellular growth in these conditions. Six of nine tumors tested also formed colonies in suspension in semisolid or liquid conditions which did not permit the growth of normal glial cells. Astrocytomas and medulloblastomas have distinctive growth patterns both in monolayer and in suspension culture. Fetal brain from midtrimester abortions contained cells which, like tumor, formed colonies in suspension. The semisolid culture system was then used to test the sensitivity of brain tumor stem cells to drugs and radiation in vitro. Survival curves representative of our experience with the medulloblastomas and astrocytomas are presented. It is concluded that the system may have value in screening new agents for activity against children's brain tumors but because of the relative rarity of these diseases, a cooperative effort would be required to produce useful results.

Adolescent↗
PubMed1985

Poisonings.

While the three demonstration programs failed to document a major impact on prevention of poisoning, they do provide a rationale for selected strategies that may have wide application. Future efforts and successes in poison prevention will involve both the primary care physician and the poison center, using primary and passive interventions. The primary physician can be a source of information and counseling, while the poison center, having succeeded in secondary prevention, can expand its role into primary prevention.

Adolescent↗
PubMed1985

Quantitation of pulmonary gallium-67 uptake: comparison of computer-derived indices.

A variety of computer-derived indices of pulmonary gallium-67 were compared in 51 subjects with and without interstitial lung disorders. An index which quantitates lung uptake in relation to liver uptake, both being corrected for tissue background activity over the thigh, was the most reliable in differentiating between the two patient groups. The index is easily derived using standard computer techniques, so permitting further studies to assess its role in serial assessments of the progress of these disorders.

Computers↗
PubMed1985

Erythrocyte selenium-75 uptake as a measure of selenium status in weaner sheep, and its relationship to erythrocyte glutathione peroxidase activity.

The relationship between in vitro erythrocyte 75Se uptake (75Se uptake) and erythrocyte glutathione peroxidase (EGSHPx) activity was examined in weaner sheep during periods of selenium depletion and repletion, to determine whether 75Se uptake was better correlated than EGSHPx activity to the development of weaner nutritional myopathy. In the 2 trials conducted, only 3 of 45 Merino wether weaners developed clinical myopathy and histological lesions in skeletal muscles. The 75Se uptake values and EGSHPx activities in these 3 sheep were no different from those in the unaffected sheep. There was a significant negative correlation between 75Se uptake values and EGSHPx activities over the entire period of the trials. It could not be demonstrated that 75Se uptake was any better correlated than EGSHPx activity to the development of nutritional myopathy, and it was concluded that EGSHPx activity indicated selenium status better than 75Se uptake in weaner sheep.

Animals↗
PubMed1984

Sustained release nitroglycerin improves myocardial thallium-201 images in men with coronary artery disease.

Ten men with coronary disease and angina-limited exercise participated in a study of the effects of sustained release nitroglycerin capsules on exercise performance and myocardial thallium images. Dose titration to ascertain the maximally tolerated dose, 6.5 to 26 mg orally four times a day, followed by double-blind, placebo-controlled cross-over treatment was undertaken. Following the administration of sustained release nitroglycerin exercise performance and exercise thallium images improved and appeared to remain so for four hours.

Administration, Oral↗
PubMed1983

Thallium-201 myocardial imaging during maximal and submaximal exercise: comparison of submaximal exercise with propranolol.

Propranolol is an effective drug for patients with angina and has been shown to favorably alter exercise ejection fraction and myocardial perfusion images in patients with coronary disease. A characteristic effect of propranolol is reduction in exercise heart rate (HR). Twenty men with coronary disease (10 with prior infarction), angina-limited exercise tests, abnormal myocardial blood flow distribution images (MBFDI) (201thallium) during exercise, and normal resting ejection fractions underwent treadmill exercise testing with imaging on three occasions. Control maximal exercise was performed initially with measurement of MBFDI. Propranolol, 40 mg by mouth four times a day, was administered for a week with exercise repeated to the same workload. A third study, with men off propranolol, was undertaken with exercise continued only to the HR obtained while the men were taking propranolol (submaximal exercise). All men had improvement in MBFDI while receiving propranolol (men without infarction +780 +/- 88 [average +/- SEM] normalized count rate difference between control and propranolol; men with infarction +724 +/- 73 normalized counts). Greater count differences were noted when control exercise and HR-controlled, submaximal exercise MBFDI were compared with a greater difference in men with infarction (+1094 +/- 89 normalized counts) than for men without infarction (+896 +/- 88 normalized counts). Results suggest that propranolol improves MBFDI during exercise in men with angina, but that submaximal exercise results in more normal MBFDI than does propranolol for exercise to the same HR.

Angina Pectoris↗
PubMed1982

Efficacy of diltiazem in angina on effort: a multicenter trial.

During a multicenter study 57 patients with exercise-induced angina were evaluated with serial exercise testing to assess the efficacy of diltiazem, a calcium slow channel blocking agent, compared with a placebo. The study consisted of a 1 week single-blind placebo stabilization period followed by a double-blind triple crossover between diltiazem and placebo. Three dose levels were tested (120, 180 and 240 mg/day) in each patient. For the three time-related variables there was a significant dose-related response, with 240 mg/day being the most effective. The increases, over the washout placebo stabilization values, of the time-related variables for the 240 mg/day week compared with the corresponding placebo week were total duration of exercise 1.87 versus 1.05 minutes (p less than 0.002), time to onset of angina 1.81 versus 1.17 minutes (p less than 0.01) and time to appearance of 1 mm S-T segment depression 1.81 versus 1.01 minutes (p less than 0.002). Analysis of exercise variables indicated a significant reduction in heart rate, diastolic blood pressure, and pressure-rate product at submaximal exercise after administration of diltiazem. Diastolic blood pressure was significantly reduced at maximal exercise. Heart rate and pressure-rate product were unchanged at rest during submaximal or maximal exercise. Submaximal and maximal exercise S-T depression was not significantly altered by diltiazem. The reduction in pressure-rate product at submaximal exercise was a possible mechanism for the drug's beneficial effect in enhancing the three time-related variables.

Adult↗
PubMed1982

An improved bioassay for cytokinins using cucumber cotyledons.

The cucumber cotyledon greening bioassay is frequently used for detecting cytokinins. Beneficial modifications of the original technique included using 5-day-old cucumber (Cucumus sativus L., cv. National Pickling) cotyledons treated with combinations of 40 millimolar KCl and various concentrations of cytokinins. A dark incubation period of 20 hours was followed by an exposure to light for 3.5 hours. Under these conditions, extremely low (0.0001 milligram per liter) concentrations of N(6)-benzyladenine, zeatin, kinetin, or zeatin riboside can be detected. Of the four cytokinins tested, kinetin appeared to be the least active. With these improvements, the assay is 10 times more sensitive than is the previously described cucumber cotyledon greening bioassay for cytokinins.

Journal Article↗
PubMed1982

Importance of acute death syndrome in mortalities in broiler chicken flocks.

A survey of the weekly causes of mortality was carried out in a flock of 64,000 broiler chickens in Western Australia. Some 6.86% of the flock died or was culled in the period from day-old to slaughter and were examined post mortem. The most important cause of death, acute death syndrome (ADS) (36%), occurred during all weeks of production and 74% of affected birds were male. A comparison of liver biotin content made between 120 ADS-affected birds and 60 clinically normal flockmates established that the bottom status of ADS-affected birds was adequate.

Acute Disease↗
PubMed1982

Slow late myocardial clearance of thallium: a characteristic phenomenon in coronary artery disease.

We extended the quantitative seven-pinhole method to follow the dynamics of thallium redistribution after exercise. We observed a pattern of slow late thallium clearance that appears to be characteristic of myocardium supplied by obstructed coronary arteries. In 28 subjects, quantitative thallium scintigrams (seven-pinhole tomography, circumferential count profiles) and blood samples for thallium concentration were taken immediately, 2 hours and 4 hours after maximal treadmill exercise. Twenty subjects had coronary artery disease (CAD) and eight were normal. The rate of thallium clearance from the blood (TCB) was compared with the rate of thallium clearance from each segmental region of myocardium (TCM, derived by ratioing corresponding segments of the absolute circumferential count profiles) between the 2- and 4-hour images. In seven of the eight normal subjects, TCM exceeded TCB in all regions of all images (specificity 88%). Seventeen of the 20 CAD patients had at least one region where TCM was less than TCB (sensitivity 85%). Of the 13 patients with multivessel CAD, 11 had multiple regions with TCM less than TCB. Using this criterion, we detected 31 of 39 obstructed coronary arteries. Of the 37 regions that were abnormal by this analysis, 30 corresponded to obstructed coronary arteries. In contrast, while conventional circumferential count profile analysis also was abnormal in 17 of the 20 CAD patients, it diagnosed multivessel CAD in only five of the 13 patients that had it. These results show that slow late thallium clearance from myocardium is characteristic of regions of myocardium supplied by diseased coronary arteries and that observation of this phenomenon may improve diagnostic sensitivity for the presence of multivessel CAD.

Coronary Disease↗
PubMed1982

Favorable effects of acebutolol on exercise performance and angina in men with coronary artery disease.

Acebutolol, a relatively cardioselective beta-adrenergic blocking drug, was administered to 20 men with coronary artery disease and angina. A three month double-blind cross-over (placebo and acebutolol) design was used following a 12-week placebo phase and a six-week dose-titration phase. During the cross-over phase, acebutolol (400 mg in 19 men and 300 mg in one, orally three times per day) increased the duration of treadmill exercise (placebo, 6.8 +/- 0.5) min [average +/- SEM]; acebutolol, 8.1 +/- 0.6 min; P less than 0.05) and decreased the frequency of ST segment depression during exercise (placebo, 12 or 20 men; acebutolol, 6 of 20 men). The heart rate x systolic blood pressure product (x 10(-2)) was decreased both at rest (placebo, 105.0 +/- 4.0; acebutolol, 84.0 +/- 3.0; P less than 0.01) and during exercise (placebo, 199.0 +/- 10.0; acebutolol, 144.0 +/- 8.0; P less than 0.01). Acebutolol treatment decreased the frequency of angina (diary cards) (placebo, 9.0 +/- 2.4 episodes per week; acebutolol, 6.4 +/- 2.2 episodes per week; P less than 0.05) and decreased the consumption of nitroglycerin (placebo, 9.0 +/- 4.4 tablets per week; acebutolol, 7.4 +/- 4.0 tablets per week; P less than 0.05). Results suggest that acebutolol increases exercise performance and decreases the occurrence of angina in men with coronary disease.

Acebutolol↗
PubMed1982

Long-term effects of oppositional child treatment with mothers as therapists and therapist trainers.

The follow-up data reported represent a long-term (3 to 9 years out of treatment) evaluation of 40 children who were clients of the Regional Intervention Program (RIP) from 1969 to 1978. As 3-, 4-, and 5-year olds, these youngsters exhibited severe and prolonged tantrums, continual opposition to adults' requests and commands, and physical aggression toward parents. Each child and mother participated in a standardized intervention package modeled after Wahler's Opposition Child Treatment. Results from school and home-based follow-up showed that: (a) commands, demands, or requests made by parents were likely to be followed by former clients' compliance; (b) former clients' social interactions in the homes were overwhelmingly positive and their nonsocial behavior was by and large appropriate; (c) parent behavior in the home was consistent with the child management skills taught many years ago; (d) there were no differences between the compliant, on-task, social interaction and appropriate/inappropriate nonsocial behaviors of former clients and randomly selected class peers; (e) there were no differences in teachers' commands, negative feedback, positive social reinforcement, and repeated commands that were directed toward either former clients or randomly selected class peers; (f) both teachers' and parents' rating of former clients on the modified Walker Problem Behavior Checklist were highly correlated; (g) there were no differences in teachers' rating of former clients and class peers; and (h) of all the studied demographic variables, only age that treatment began and family intactness were related to current levels of behavior.

Behavior Therapy↗
PubMed1982

Effect of biotin supplementation on incidence of acute death syndrome in broiler chickens.

This study examined the effect of supplementary biotin on the incidence of acute death syndrome (ADS) and total mortality in a commercial flock of 64,000 broiler chickens. Biotin supplementation via the drinking water at 20 and 100 micrograms/day supplied 1.2 to 5 times or 6 to 25 times the level recommended by the National Research Council for different stages of growth from day-old to slaughter. Uptake of biotin was confirmed by radioisotopic analysis of liver biotin content of both ADS-affected birds and clinically normal birds. Treatment groups did not differ significantly from the control group with respect to total mortality, ADS mortality, feed conversion ratio, or slaughter weight. High levels of biotin supplementation neither prevented ADS nor reduced total mortalities in the flock.

Administration, Oral↗
PubMed1982

Single-photon emission tomography with a 12-pinhole collimator.

To assess the advantages of more complete angular sampling and of more views in the tomographic reconstruction process, tomographic imaging with a 12-pinhole (12PH) collimator has been compared with 7-pinhole tomography (7PH). The 12PH system gives a 50% increase in sensitivity but resolution degrades more rapidly with depth. The 7PH and 12PH systems provide similar accuracy of detection of lesions in a myocardial ring phantom. The 7PH images, however, demonstrated more noise and "ripple" artifacts. The 12PH system offers a larger reconstruction volume and generates fewer artifacts when the collimator is misaligned with the myocardial long-axis, thus making patient positioning less critical than with 7PH. A disadvantage is that individual views are minified by the 12PH collimator, and a 256 X 256 image matrix should be used during image acquisition to limit digital sampling errors.

Evaluation Studies as Topic↗