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Biomedical subjects

R C Horton

Publications and source records attributed to R C Horton.

At least 19 recordsLinked to original sources
PubMed1994

Microalbumin excretion in patients with positive exercise electrocardiogram tests.

Thirty-three subjects underwent exercise electrocardiogram testing, 20 had a history of myocardial infarction and 13 were age-matched volunteers. Exercise electrocardiograms were positive in 15 subjects, negative in 12 and anomalous in six. Urinary microalbumin excretion was measured at rest, 30 and 60 min after exercise. Urinary microalbumin excretion was expressed as the albumin-creatinine ratio in mg.mmol-1. In the positive exercise electrocardiogram group median albumin-creatinine ratio increased from 1.0 mg.mmol-1 (95% CI 0.94-1.49) at rest to 2.0 mg.mmol-1 (95% CI 1.51-3.94) 30 min after exercise, whilst in the negative electrocardiogram group median resting and 30 min post exercise albumin-creatinine ratio values of 0.85 (95% CI 0.53-1.32) and 1.80 (95% CI 0.63-2.32) mg.mmol-1 respectively were not significantly different. These results suggest that exercise-induced myocardial ischaemia is associated with increased urinary microalbumin excretion.

Albuminuria↗
PubMed1993

Endoscopic extraction of bile duct stones: management related to stone size.

Endoscopic sphincterotomy has become the first line treatment for patients with common bile duct (CBD) stones. This technique may fail, however, due to difficult anatomy, previous surgery, periampullary diverticula or the presence of a large stone. The importance of stone size to the success of endoscopic sphincterotomy has not been fully assessed. A prospective study was carried out over the period January 1987 to December 1989 on 100 patients (45 male, 55 female, median age 69 years, range 19-97) with CBD stones in which a policy of early duct clearance was followed. Endoscopic retrograde cholangiopancreatography (ERCP) was performed and the stone size and number recorded from the cholangiograms and corrected for magnification. Sphincterotomy was performed using a diathermy unit with a cutting current and stones were extracted using a balloon catheter or a Dormia basket. Of the 100 patients with CBD stones receiving ERCP, successful clearance of the biliary tree was possible in seven without endoscopic sphincterotomy and five were felt to be unsuitable for endoscopic sphincterotomy. Of the remaining 88 patients endoscopic sphincterotomy was successful in 75 (85%). Of the 75 patients having endoscopic sphincterotomy stone clearance was successful in 44 (59%). There were no deaths and only four complications, which rapidly resolved on conservative treatment (two acute pancreatitis, two bleeding). The number of CBD stones present was similar in those patients with successful endoscopic sphincterotomy and duct clearance (median 1, range 1-10, n = 44) as in those in whom it failed (median 2, range 1-6, n = 31). In contrast there was a highly significant difference when stone size was analysed (successful clearance median stone size 10 mm, range 3-27 mm; unsuccessful: median 18 mm, range 10-42, p<0.001). Stones less than 10 mm in diameter (n=21) were all removed successfully whereas in patients with stones over 15 mm (n=25) only three were removed endoscopically (12%). All patients with evidence of residual stones had additional treatment. Of these 31 patients, 10 had surgery, 11 had insertion of an endoprosthesis, and 10 had dissolution treatment with methyl-tert-butyl ether through a nasobiliary catheter. This study shows the importance of stone size to the success rate of endoscopic removal of bile duct stones.

Adult↗
PubMed1992

A metabolic assessment of the beta 1 selectivity of bisoprolol.

Twelve healthy volunteers were given single oral doses of bisoprolol 5 mg, 10 mg and 20 mg and atenolol 50 mg and 100 mg in a randomised, placebo-controlled study. The effects of these drugs on beta 2-stimulated hypokalaemia and hyperglycaemia (produced by intravenous terbutaline infusion) were studied. Comparable beta-blockade was achieved with bisoprolol 20 mg, and atenolol 50 mg and 100 mg as measured by attenuation of exercise heart rate. Measurements of areas under or over the curve (AUC and AOC) of hypokalaemic or hyperglycaemic response to terbutaline infusion showed that bisoprolol (10 mg and 20 mg) and atenolol (50 mg and 100 mg) were significantly less beta 1 selective than 5 mg bisoprolol. Furthermore, there was a trend towards decreasing beta 1 selectivity with increasing doses of bisoprolol. Bisoprolol, an effective once daily antihypertensive and antianginal treatment, has comparable beta 1 selectivity to atenolol as measured by metabolic response. At a dose of 5 mg, bisoprolol has a measurable impact on beta 1 receptors but minimal effect on beta 2 receptors.

Adrenergic beta-Antagonists↗