Search PubMed⌕ Search

Biomedical subjects

J McEwan

Publications and source records attributed to J McEwan.

At least 37 records · Page 2Linked to original sources
PubMed1993

Nonvisualization of suppressed thyroid tissue on Tl-201 scintigraphy.

Tl-201 scintigraphy has been used to visualize thyroid tissue that is suppressed by an autonomously functioning thyroid nodule. Reports have indicated that the sensitivity of this technique rivals that obtained by I-123 scanning after thyroid-stimulating hormone stimulation. We report a case of triiodothyronine toxicosis caused by an autonomously functioning thyroid nodule in which the suppressed thyroid tissue was not visualized on Tl-201 scintigraphy. The suppressed tissue was readily identified with ultrasound imaging, which demonstrates the utility of this technique in differentiating between thyroid suppression and agenesis.

Adult↗
PubMed1992

Nonpustular psoriatic lesions detected by Tc-99m HMPAO labeled granulocytes.

A patient with a fever of unknown origin was evaluated by abdominal SPECT using Tc-99m HMPAO labeled granulocytes and a triple detector camera. Although no abscesses were located, nonpustular psoriatic skin lesions were demonstrated incidentally on the reprojectional images. Psoriatic scales contain a chemotactic factor for leukocytes, and this is a likely explanation for the increased uptake of the radiotracer by psoriatic lesions.

Fever of Unknown Origin↗
PubMed1990

Action of calcitonin gene-related peptide upon bovine vascular endothelial and smooth muscle cells grown in isolation and co-culture.

1. Bovine aortic endothelial cells (BAE) and smooth muscle cells (BASM) were grown separately and in co-culture. 2. Calcitonin gene-related peptide (CGRP) caused dose-dependent activation of adenylate cyclase in each cell type when grown in isolation. The concentration of CGRP causing half-maximal activation in BAE and BASM was 200 nM and 310 nM, respectively. 3. In cells grown in co-culture exposure to bradykinin produced dose-dependent elevations in cyclic GMP content which were maximal 1 min after application of the agonist. 4. CGRP (1 nM-1 microM) did not stimulate a rise in cyclic GMP in co-cultures. 5. Displaceable CGRP binding was identified throughout the wall of the bovine aorta. 6. We conclude that CGRP receptors coupled to adenylate cyclase are present on BAE and BASM, but there is no coupling of these receptors to the release of any agent (such as endothelium-derived relaxing factor) that activates guanylate cyclase.

Adenylyl Cyclases↗
PubMed1989

Brown adipose tissue in lean and fat selection lines of sheep identified by immunodetection of uncoupling protein in western blots of tissue homogenates.

1. Uncoupling protein (UCP) was purified from perirenal adipose tissue of 2-day-old lambs by a procedure involving Triton solubilization and hydroxyapatite treatment. It has an apparent Mr of 34,000. 2. Rabbit anti-sheep UCP and rabbit anti-rat UCP each cross-reacted with both rat and sheep UCP in Western blots, indicating that the major antigenic determinants of the sheep UCP and rat UCP are similar. 3. In Western blots, the anti-sheep UCP showed tissue specificity by detecting a band corresponding to UCP only in brown adipose tissue, but not in heart or liver homogenates. 4. The Western blotting procedure was used to analyse sheep tissues. UCP was detected in samples of perirenal, omental, back and lymph node fat from 2-day-old lambs, but not in heart, liver, muscle or kidney samples. 5. UCP was not detected in any tissue samples from 34-day-old or 7-month-old lambs. 6. Comparison of the amount of UCP in perirenal fat of 2-day-old lambs from lean, fat and control selection lines, using the Western blotting procedure, showed no apparent difference.

Adipose Tissue↗
PubMed1987

Human calcitonin gene-related peptide activates adenylate cyclase and releases prostacyclin from human umbilical vein endothelial cells.

1 Endothelial cells of human umbilical vein were isolated and cultured in vitro. 2 In these cells there was a concentration-dependent release of prostacyclin and activation of adenylate cyclase by human calcitonin gene-related peptide (hCGRP). The concentration of hCGRP for half-maximum activation of adenylate cyclase (Kact) by hCGRP was 190 nM. 3 Bradykinin induced a ten fold greater release of prostacyclin than CGRP, but did not activate adenylate cyclase. 4 hCGRP may exert its potent vasodilator properties by stimulating release of vasorelaxant substances, including prostacyclin from endothelial cells.

6-Ketoprostaglandin F1 alpha↗
PubMed1986

IOLSTAT--a program for comprehensive intraocular lens equation comparison with statistical analysis.

A computer program that will simultaneously solve five of the major intraocular lens (IOL) equations predicting the primary implant power required for emmetropia or ametropia is presented. The program can, alternatively, predict the degree of ametropia given the power of an IOL. The resultant predictions are analyzed using weighted and unweighted statistics, predicting a mean and a standard deviation. The results are displayed in a table which lists the prediction and the percent deviation from the weighted mean for each equation. The program features automatic averaging of keratometer readings, ultrasound axial length corrections, and an algorithm for estimating postoperative anterior chamber depth.

Algorithms↗
PubMed1986

Calcitonin gene-related peptide: a potent dilator of human epicardial coronary arteries.

To investigate the action of calcitonin gene-related peptide (CGRP) on human epicardial coronary arteries, six patients received intracoronary CGRP at doses of 50,100, and 200 ng/min. The effect of CGRP was measured angiographically with a computerized analysis system. A dose-dependent increase in coronary arterial diameter was observed. At the highest dose there were 34%, 7%, 38%, and 40% mean increases in the diameters of the circumflex, proximal, mid, and distal left anterior descending arteries, respectively. No further increase in diameter was found after a subsequent dose of 1 mg intracoronary isosorbide dinitrate. Prior infusion of CGRP did not prevent coronary arterial spasm induced by ergonovine in two patients with variant angina, but a subsequent bolus of CGRP partially relieved the spasm. We propose that CGRP has a role in the regulation of coronary vascular smooth muscle tone.

Angina Pectoris↗