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H D Royal

Publications and source records attributed to H D Royal.

At least 19 recordsLinked to original sources
PubMed1998

Recurrent gastrointestinal bleeding: use of thrombolysis with anticoagulation in diagnosis.

PURPOSE: To determine the safety and diagnostic accuracy of a provocative protocol with heparin and urokinase to induce bleeding and determine the source in patients with chronic gastrointestinal hemorrhage. MATERIALS AND METHODS: Nine patients had gastrointestinal bleeding from an indeterminate source and had negative results from esophagogastroduodenoscopy, colonoscopy, small-bowel examination, and angiography. Ten provocative bleeding studies were performed prospectively. Patients had no clinical evidence of bleeding within 2 days before the study. Intravenous administration of heparin and urokinase was performed systemically during a 4-hour period while scintigraphy was performed continuously. Mesenteric angiography was performed immediately in patients in whom substantial gastrointestinal bleeding was detected at scintigraphy. RESULTS: The provocative protocol was successful in inducing scintigraphically detectable hemorrhage in four (40%) studies within 4 hours. In two of these four studies, the source of hemorrhage was determined and treated with embolization or surgery. Three (30%) studies demonstrated scintigraphic evidence of hemorrhage only at delayed imaging (8-24 hours after initiation of the study). The remaining three (30%) studies did not show active bleeding. No complications occurred, including hemodynamic instability or uncontrollable decreases in hematocrit. CONCLUSION: Since this protocol with heparin and urokinase enabled determination of the bleeding source in only two of 10 studies, protocol modifications are necessary before this intervention is used widely.

Adult↗
PubMed1998

Whole body, adipose tissue, and forearm norepinephrine kinetics in lean and obese women.

We evaluated whole body and regional (subcutaneous abdominal adipose tissue and forearm) norepinephrine (NE) kinetics in seven lean (body mass index 21.3 +/- 0.5 kg/m2) and six upper body obese (body mass index 36.4 +/- 0.4 kg/m2) women who were matched on fat-free mass. NE kinetics were determined by infusing [3H]NE and obtaining blood samples from a radial artery, a deep forearm vein draining mostly skeletal muscle, and an abdominal vein draining subcutaneous abdominal fat. Mean systemic NE spillover tended to be higher in obese (2.82 +/- 0.49 nmol/min) than in lean (2.53 +/- 0.40 nmol/min) subjects, but the differences were not statistically significant. Adipose tissue and forearm NE spillover rates into plasma were greater in lean (0.91 +/- 0.08 pmol. 100 g tissue-1. min-1 and 1.01 +/- 0.09 pmol. 100 ml tissue-1. min-1, respectively) than in obese (0.26 +/- 0.05 pmol. 100 g tissue-1. min-1 and 0.58 +/- 0.11 pmol. 100 ml tissue-1. min-1, respectively) subjects (P < 0.01). These results demonstrate that adipose tissue is an active site for NE metabolism in humans. Adipose tissue NE spillover is considerably lower in obese than in lean women, which may contribute to the lower rate of lipolysis per kilogram of fat mass observed in obesity.

Adipose Tissue↗
PubMed1997

Nuclear medicine.

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Cardiovascular Diseases↗
PubMed1997

Effects of antiplatelet drugs on dialysis-associated platelet deposition in polytetrafluoroethylene grafts.

Hemodialysis is associated with platelet deposition in polytetrafluoroethylene (PTFE) graft fistulas. We determined whether aspirin or ticlopidine would modify this response. Patients on chronic hemodialysis with forearm loop PTFE fistulas were studied. Platelets labeled with 111indium were injected and a baseline scan of the fistula arm was made with a large field of view gamma camera. After a routine dialysis treatment, a second scan was performed within 1 hour. Four weeks later, a repeat labeled platelet study was conducted after taking either aspirin 325 mg/d or ticlopidine 250 mg/d orally for 7 days. Images were computer analyzed by drawing seven standardized regions along each graft. The counts per second per pixel in postdialysis images were compared with predialysis images for each region and a percent uptake compared with the predialysis image was calculated. Regions with dialysis-induced uptake of more than 1.5-fold compared with the predialysis image before antiplatelet drug therapy were compared with these same regions after therapy. Six patients were studied before and after aspirin therapy. Uptakes larger than 1.5-fold over predialysis images were found in 12 of 40 regions and were 292% +/- 50% (+/-SEM) before and 193% +/- 25% of predialysis values after aspirin (P = 0.02, paired t-test). Uptakes in the remaining regions were 107% +/- 4% before and 115% +/- 6% after aspirin (P = NS). A second group was studied before and after ticlopidine (n = 5). Uptakes increased by more than 1.5-fold compared with predialysis images in 19 of 30 regions and had a median of 286% increased uptake (mean, 785% +/- 374%) before and 160% (153% +/- 10%) after drug therapy (P < 0.001, Wilcoxon). Uptakes in the remaining regions were 116% +/- 5% before and 134% +/- 13% after drug therapy (P = NS). Platelet aggregation studies suggested compliance with both drugs. These studies show that these antiplatelet drugs reduce, but do not completely prevent, dialysis-associated radiolabeled platelet deposition in PTFE grafts.

Arteriovenous Shunt, Surgical↗
PubMed1996

Nasopharyngeal radium irradiation: fundamental considerations.

This article discusses the potential carcinogenic effects of radiation exposure from nasopharyngeal radium irradiation exposure and issues to consider when deciding whether to recommend screening for asymptomatic patients who have been treated by nasopharyngeal radium irradiation. The radiation exposure from the radium is primarily the result of gamma-rays, which are very penetrating. beta-Particles would affect only the tissues located within 1 cm of the eustachian tube orifice. On the basis of a quantitative risk assessment, the lifetime risk of brain cancer developing was estimated to be approximately 3 per 1000 persons, and the lifetime risk of a fatal cancer 5.6 per 1000 persons. When the medical benefits of screening asymptomatic patients are assessed, several factors, including the medical risks and benefits and cost-effectiveness of follow-up, should be considered.

Eustachian Tube↗
PubMed1995

The effects of hemodialysis on platelet deposition in prosthetic graft fistulas.

The effects of hemodialysis on the coagulation system are not completely understood. The purpose of these studies was to determine the effects of hemodialysis on platelet deposition in prosthetic graft fistulas. Nine patients with polytetrafluoroethylene graft fistulas and two with native vein fistulas were studied. Dialysis was performed thrice weekly with blood flow rates of 400 to 450 mL/min and regenerated cellulose hollow-fiber dialyzers. Platelets were labeled with oxine-111indium. Images of the fistula were obtained immediately after injection (baseline study), postdialysis the same day, the following morning, and before and after the next two routine treatments. Images were analyzed by drawing regions of interest, and activities were expressed as counts per pixel and percent baseline after correction for background and biologic clearance and physical decay. There was a marked dialysis-associated enhancement of platelet deposition in sites along the graft. More than a twofold increase in uptake was noted most frequently in the arterial anastomosis, arterial loop, midloop, venous loop, and venous anastomosis regions. The arterial loop and midloop regions were most consistently affected. The arterial side of the loop during the first dialysis treatment showed an increase from 15 +/- 3 counts/pixel (+/- SE) predialysis to 46 +/- 14 counts/pixel postdialysis (P = 0.03, Mann-Whitney). The uptake increased with dialysis in the midloop region from 12 +/- 2 counts/pixel to 40 +/- 11 counts/pixel (P = 0.04, paired t-test). The uptake was nearly reversed by the next dialysis treatment. Subsequent treatments had a similar pattern. No significant change in activity was found in the two patients with native vein fistulas.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗