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Biomedical subjects

S Copeland

Publications and source records attributed to S Copeland.

32 records · Page 2Linked to original sources
PubMed1988

Effect of low versus conventional dose cyclopenthiazide on platelet intracellular calcium in mild essential hypertension.

Platelet free intracellular calcium levels were measured during a double-blind, placebo-controlled parallel study to investigate the antihypertensive activity of 50 micrograms, 125 micrograms, and 500 micrograms cyclopenthiazide, in mild essential hypertension. Cytosolic free calcium levels were significantly higher in established hypertensive patients (135 +/- 28 nmol/l, P less than 0.001) but not in borderline hypertensive patients (123 +/- 26 nmol/l) compared with normotensive controls (111 +/- 9 nmol/l). A positive correlation between platelet free calcium level and systolic and diastolic blood pressure was confirmed (n = 68; r = 0.309 P = 0.01; r = 0.405 P less than 0.001, respectively). The 125-micrograms and 500-microgram doses of cyclopenthiazide produced mean decrements in blood pressure of 18/10 mmHg and 23/8 mmHg, respectively, (P less than 0.05 for both), after 8 weeks of therapy. The 50-microgram dose displayed no useful antihypertensive activity. Platelet free calcium levels fell by a similar amount in the four groups. The fall in blood pressure produced by the 125 and 500-microgram doses of cyclopenthiazide did not correlate with changes in platelet [Ca2+]i (r = 0.166 systolic and r = 0.169 diastolic). These findings do not support the hypothesis that changes in platelet cytosolic calcium levels are determined by the same factors that control blood pressure.

Blood Platelets↗
PubMed1988

Short-term effects of alcohol on peripheral blood flow, platelet aggregation and noradrenaline output in normal man.

The effects of acute oral administration of alcohol on finger and forearm blood flow, platelet aggregation and plasma noradrenaline were examined over a three-hour period in a group of healthy male volunteers. Finger blood flow was increased at 15, 30 and 60 min and skin temperature was raised at 30 and 60 min. Digital systolic blood pressure was decreased at 15 and 30 min. No change in forearm blood flow was observed. A linear correlation was observed between finger blood flow, skin temperature and plasma alcohol concentrations. No significant changes were observed in platelet aggregation nor in plasma noradrenaline levels. Alcohol appears to have a greater effect on digital and skin blood flow as compared with muscle blood flow.

Administration, Oral↗
PubMed1987

The effect of chronic captopril therapy on platelet angiotensin II receptor density and vascular responsiveness to angiotensin II infusion.

The density of angiotensin II (Ang II) receptors on the platelet and the vascular responsiveness to infused angiotensin II before and after two weeks of captopril therapy were examined in ten healthy male volunteers. There was a significant increase in blood flow to the forearm, but no significant changes in either the density of angiotensin II receptors or the pressor response to infused angiotensin II following captopril therapy. The study demonstrates that long term reduction of angiotensin II formation by captopril in man does not increase the responsiveness of the receptors to infused angiotensin, nor results in an "up regulation" of the angiotensin receptors. It also provides further evidence that some of the long term vasodilator effects of captopril may be mediated by mechanisms other than inhibition of angiotensin I (Ang I) converting enzyme.

Adolescent↗
PubMed1987

The effect of chronic captopril therapy on adrenergic receptors, plasma noradrenaline and the vascular responses to infused noradrenaline.

Adrenergic receptors (alpha 2, beta 2), plasma noradrenaline, heart rate and the pressor responsiveness to infused noradrenaline were examined in ten healthy male volunteers before and after 2 weeks of placebo or captopril therapy in a double blind cross-over study. No significant differences in these measurements were observed between the captopril and placebo treated groups. The study shows that in sodium replete normotensive subjects, long-term angiotensin converting enzyme inhibition does not lead to changes in adrenoceptor density. There is also no alteration in plasma noradrenaline levels nor in the pressor responsiveness to infused noradrenaline. These data suggest that the known interaction between the renin-angiotensin system and the sympathetic nervous system observed in animals is probably of little significance in man.

Adult↗
PubMed1986

Root resorption in maxillary central incisors following active orthodontic treatment.

The purpose of this study was to determine if apical root resorption associated with orthodontic treatment continues after the termination of active treatment (that is, the removal of fixed appliances). A sample of 45 subjects who had experienced root resorption during treatment was selected from the orthodontic clinic at the State University of New York at Buffalo. The length of the maxillary central incisors was measured from lateral cephalometric radiograms taken before treatment, after active treatment, and after retention. From these data, the resorption occurring during and after active treatment was calculated. The mean amount of root resorption during active treatment was 2.93 mm. The mean amount of root resorption during the posttreatment period was 0.1 mm. There was a statistical difference between these two means using the Student's t test at the 0.05 level of significance. The reliability coefficient comparing the first tracings and measurements in the 19 cases that were retraced and remeasured was r = 0.993. The data from this radiographic study support the hypothesis that root resorption associated with orthodontic treatment ceases with the termination of active treatment. There was also evidence to suggest that when posttreatment root resorption does occur, it is not necessarily associated with large amounts of root resorption during the active treatment period. It is more likely associated with other factors, such as traumatic occlusion and active force-delivering retainers.

Adolescent↗
PubMed1984

Pharmacodynamics and pharmacokinetics of digoxin in the presence of lithium.

Previous biochemical and clinical data suggest there may be an interaction between digoxin and lithium. The pharmacodynamics and pharmacokinetics of an intravenous infusion of digoxin were studied in six male subjects before and after 2 weeks treatment with lithium carbonate. The effects of lithium on sodium pump activity, intracellular electrolytes and extracellular electrolytes were studied. No significant interaction between digoxin and lithium was found. No significant effects of lithium on sodium pump activity or electrolyte concentrations were found.

Adolescent↗
PubMed1983

Erythrocyte cation transport and age: effects of digoxin and furosemide.

The uptake of rubidium 86 (86Rb) by human erythrocytes was measured at various ages. Effects of digoxin and furosemide on this process were examined and, in the case of digoxin, related to its numbers of specific cellular binding sites. There were no significant effects of age on absolute cellular Rb uptake, digoxin-sensitive Rb uptake, or numbers of cellular binding sites for digoxin, but the ability of digoxin to inhibit digoxin-sensitive 86Rb uptake increased with age. The ability of furosemide to inhibit digoxin-insensitive 86Rb uptake did not change with age. Results suggest a dynamic contribution to altered sensitivity to digoxin in elderly persons.

Adolescent↗
PubMed1980

Disruption of the acromioclavicular joint: surgical anatomy and biological reconstruction.

The pathological anatomy of acromioclavicular joint disruption is discussed in the light of operative findings. A method of repairing the dislocated joint is described using the coraco-acromial ligament and temporary internal fixation. It has been found to be useful in those patients who present late with pain and symptoms of instability.

Acromioclavicular Joint↗
PubMedDate not supplied

Reossification and fusion across the acromioclavicular joint after arthroscopic acromioplasty and distal clavicle resection.

Arthroscopic acromioplasty and distal clavicle resection has now become an accepted method of treatment for acromioclavicular (AC) joint arthritis. Complications following arthroscopic acromioplasty are relatively uncommon and include instrument breakage, hematoma, traction neuropathy, infection, acromial fracture, reflex sympathetic dystrophy, and recurrence of symptoms. Although heterotopic ossification within the soft tissues has also been reported, complete reossification of the resected clavicle has not. We report a case of reossification of the clavicle and fusion across the AC joint following arthroscopic acromioplasty and distal clavicle resection.

Acromioclavicular Joint↗
PubMedDate not supplied

Viral tracheitis in goslings in Saskatchewan.

Up to 12% mortality occurred in goslings between 4 and 11 days of age in two sequential hatches from a single breeder flock. Respiratory signs were noted before the birds died. The most consistent necropsy finding was a white opaque plug of fibrin and cellular debris in the trachea. The tracheal epithelium was hyperplastic and metaplastic with intranuclear inclusion bodies present in superficial cells. An adenovirus was isolated in both chicken and goose embryo liver cells.

Adenoviridae Infections↗