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Biomedical subjects

R Long

Publications and source records attributed to R Long.

At least 127 records · Page 7Linked to original sources
PubMed1981

Intractable diarrhoea in a patient with vasoactive intestinal peptide-secreting neuroblastoma. Attempted control by somatostatin.

A 1 1/2 year old child developed profuse watery diarrhoea, shown to be due to excessive plasma vasoactive intestinal peptide (VIP) levels, whilst on treatment for metastatic neuroblastoma. Because it was unresponsive to alternative treatment, an attempt was made to control the diarrhoea with a somatostatin infusion. The attempt failed despite the fact that serum VIP levels were substantially reduced. Possible reasons for failure are discussed and the importance of plasma VIP as a marker for maturation in neuroblastoma emphasised.

Diarrhea↗
PubMed1981

Lack of difference in digoxin urinary excretion with two intravenous infusion rates.

Ten normal subjects were given 0.4 mg digoxin intravenously by bolus injection over 3 to 5 min and by constant-rate infusion for 1 hr. Urinary excretion of digoxin over the next 6 days, as measured by radioimmunoassay, was similar after both the rates of intravenous injection. In one subject, who excreted substantial amounts of digoxin reduction products, no difference was apparent in the amount of reduced metabolites excreted. These results are not in agreement with previous reports of an effect of intravenous infusion rate on urinary digoxin excretion.

Adult↗
PubMed1980

Differentiation between reperfusion and occlusion myocardial necrosis with technetium-99m pyrophospate scans.

Although infarct-avid scanning is used to diagnose myocardial infarction, no distinction is made between two very different mechanisms of myocardial cell death. These are occlusion necrosis and reperfusion necrosis. The former is the major form of cell injury after a sustained occlusion of a coronary artery; the latter occurs immediately after reperfusion of ischemic myocardium. The present study examines whether the technetium pyrophosphate scan becomes positive more rapidly with one form of injury rather than the other. Myocardial damage was produced in dogs by either sustained coronary occlusion (Group I, 6 dogs) or reperfusion (Group II, 18 dogs). Infarct-avid myocardial scans obtained with technetium-99m pyrophosphate were positive in only one of six animals in Group I when isotope was injected 4.5 hours after sustained coronary occlusion. In contrast, 12 or 13 animals (Group IIa) with reperfusion necrosis had a positive scan when isotope was injected 3.5 hours after reperfusion. When isotope was injected only 30 minutes after the onset of reperfusion (Group IIb), only two of five scans were clearly positive. The results indicate that if the interval between myocardial injury and a positive scan is known, inference can be made concerning the predominant type of injury.

Animals↗
PubMed1980

Causes of perioperative myocardial infarction: their identification and prevention.

Despite major technical advances in coronary bypass surgery and myocardial preservation, perioperative infarction remains a serious problem. The authors review the pathogenesis of the two different types of myocardial injury, occlusion necrosis and reperfusion necrosis. These two entities can be distinguished clinically by radioisotope scanning. Experimental studies have demonstrated that reperfusion necrosis can be prevented pharmacologically. Since the majority of perioperative infarcts are probably due to reperfusion, the importance of distinguishing between these two entities is evident.

Animals↗
PubMed1979

After the Act.

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Community Health Nursing↗
PubMed1979

Renin-angiotensin system in phlorhizin compared with alloxan diabetes in the rat.

In alloxan-treated diabetic rats, plasma renin activity (PRA) is decreased. One possible mechanism that may explain the decreased PRA is an increased delivery of sodium to the macula densa produced by the glucose osmotic diuresis, resulting in decreased renin release. To evaluate this possible mechanism, rats with phlorhizin diabetes, which produces a glucose osmotic diuresis without hyperglycemia, were studied and compared with rats with alloxan-induced diabetes. Whereas phlorhizin-treated rats had low blood glucose and alloxan-treated rats had elevated glucose, the glucose osmotic diuresis was similar in the two groups. PRA and plasma renin concentration (PRC) were significantly increased in the phlorhizin group. In the alloxan group, PRA was decreased and angiotensin II sensitivity increased, both significantly. Plasma renin substrate (PRS) remained adequate in each group. These results suggest that the decreased PRA in alloxan-induced diabetes is due neither to factors associated with the glucose osmotic diuresis including changes in renal tubular sodium not to decreased PRS.

Alloxan↗
PubMed1978

Use and abuse.

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Humans↗
PubMed1978

Steroid priming of the luteinizing hormone response to luteinizing hormone releasing hormone.

Perifusion experiments were performed to study the stimulatory effects of luteinizing hormone releasing hormone (LH-RH) on the release of LH from anterior pituitary tissue. Exposure of pituitary tissue from normal male rats to LH-RH (5 ng/ml for 5 min) induced a small release of LH; in tissue from ovariectomized rats receiving no pretreatment, the release was more than three times greater and in tissue from gonadectomized male or female rats pretreated with oestradiol benzoate and progesterone, the release was six times greater than that observed in normal rats. Further exposure of pituitary tissue from gonadectomized steroid-pretreated male and female rats to LH-RH (5 ng/ml) induced an increase in the level of LH even greater than that seen after the initial exposure (priming action of LH-RH); in tissue from ovariectomized rats receiving no pretreatment, less LH was released than after the first exposure to LH-RH and in tissue from normal male rats the response was unchanged.

Animals↗
PubMed1976

Management of uremic pericarditis: a report of 11 patients with cardiac tamponade and a review of the literature.

Uremic pericarditis remains a significant cause of morbidity and mortality in most hemodialysis programs. A review of the literature and out own experience show that uremic pericarditis should be vigorously treated when detected. Usually an increase in the dialysis program with regional heparinization is sufficient to control the pericarditis. When signs of pericardial effusion are manifested, patients often progress rapidly to cardiac tamponade. A surgical anterolateral pericardiectomy is the most satisfactory measure in controlling pericardial effusion and preventing fatal cardiac tamponade. Although these patients have severely impaired renal function, the operation can be performed safely with a low morbidity and mortality.

Adolescent↗