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Biomedical subjects

A Hedges

Publications and source records attributed to A Hedges.

At least 37 records · Page 2Linked to original sources
PubMed1981

Influence of cimetidine on pharmacokinetics of propranolol.

Whole-blood propranolol concentrations were estimated for 12 hours after a single 80 mg oral dose was given in six patients taking cimetidine and two weeks after they had stopped the drug. Mean blood propranolol concentrations were higher throughout the sampling period when the patients were taking cimetidine than when they were not, and the difference was statistically significant between one and four hours (p less than 0.05). The mean relative bioavailability of propranolol, measured as the area under the concentration time curve, was significantly higher when the patients were taking cimetidine (p less than 0.025). The mean increase in bioavailability was 136.5 +/- 57.6%, and the results were consistent in each subject. It is concluded from these results that cimetidine reduces the hepatic first-pass extraction of propranolol.

Adult↗
PubMed1981

Comparison of four different beta-adrenoceptor blocking drugs on lymphocyte isoprenaline-stimulated cyclic AMP production.

1 The influence of acebutolol, atenolol, pindolol and timolol on human lymphocyte cyclic AMP (cAMP) and its stimulation by isoprenaline in vitro has been studied. 2 Acebutolol and atenolol (10(-8)-10(-6)M) had no significant influence on lymphocyte cAMP levels or on isoprenaline-stimulated increase in cAMP. 3 Pindolol and timolol significantly antagonised the effect of isoprenaline, and pA2 values were calculated to be 8.12 and 8.04 respectively. This suggests that beta 2-adrenoceptors are involved in this phenomenon. 4 Only pindolol produced a significant increase in lymphocyte cAMP, which is consistent with its partial agonist activity.

Acebutolol↗
PubMed1980

A double-blind comparison of meptazinol with pethidine in postoperative pain.

Three groups each of 24 patients who had undergone total abdominal hysterectomy were studied on the 1st day after operation. Under double-blind conditions, group 1 compared meptazinol 60 mg with pethidine 100 mg, group 2, meptazinol 75 mg with pethidine 100 mg and group 3, meptazinol 100 mg with pethidine 100 mg. The drugs were given i.m. Analgesic activity was assessed by patients rating their pain before and 1 h after the administration of each treatment and by patient and investigator preference for treatment. From the pain relief score, pethidine was not significantly better than any dose of meptazinol in relieving pain. Patients preferred pethidine 100 mg to meptazinol 60 mg (P less than 0.01, McNemar's test), but there was no significant difference between meptazinol and pethidine for observer or patient preference when the dose of meptazinol was increased to 75 mg or 100 mg.

Adult↗
PubMed1980

A comparative study of antipyrine and lignocaine disposition in normal subjects and in patients treated with enzyme-inducing drugs.

1 The disposition kinetics of lignocaine and antipyrine were compared in eight normal subjects and in eleven patients receiving chronic therapy with antiepileptic drugs. The urinary excretion of D-glucaric acid (D-GA) was measured in 16 subjects. 2 In patients treated with antiepileptic drugs antipyrine clearance and D-GA excretion were significantly increased, whereas lignocaine biovailability was significantly reduced. 3 When all the subjects included in the study were considered, a significant positive correlation could be found between the apparent oral clearance of lignocaine (Dose/area under the blood concentration curve) and both antipyrine clearance (r = 0.73) and D-GA excretion (r = 0.74). 4 When normal subjects and epileptic patients were considered separately, a significant positive correlation could be confirmed between the apparent oral clearance of lignocaine and both antipyrine clearance (r = 0.71) and D-GA excretion (r = 0.76) in normal subjects, and between antipyrine clearance and D-GA excretion (r = 0.75) in epileptic patients. 5 These results suggest that the reduction of the oral availability of lignocaine in epileptic patients is secondary to induction of first-pass metabolism of the latter drug.

Adolescent↗
PubMed1978

Fecal constituents of a high-risk North American and a low-risk Finnish population for the development of large bowel cancer.

Feces collected in Kuopio, Finland, a low-risk population for colon cancer, and in the New York metropolitan area, a high-risk population for colon cancer, were compared. The dietary intake of fat and protein were the same in the two populations, but the sources of fat were different, a greater portion coming from meat in New York, and from dairy products in Kuopio. The daily stool output was higher in Kuopio due to the high intake of cereal products rich in fiber. The concentration of fecal secondary bile acids and the bacterial beta-glucuronidase activity were lower in Kuopio, but the daily output of these constituents was the same in the two groups. The daily fecal excretion of neutral sterols was higher in Kuopio than in New York. Our data suggest that the greater fecal bulk in Kuopio may dilute tumorigenic compounds which come in direct contact with the colon mucosa.

Bile Acids and Salts↗
PubMed1978

A double-blind comparison of nefopam and placebo in post-operative pain.

Nefopam (90 mg), an analgesic, was compared with placebo in a double-blind trial in patients who had undergone total abdominal hysterectomy operations. Analgesic activity was assessed by patients rating their pain before and 1 hour after administration of each treatment, by sequential analysis of patient and observer preference for treatment, and by calculation of the time interval between doses of the two treatments. Nefopam was found by observer preference to be significantly better than placebo in relieving post-operative pain. In patients with severe initial pain, the time between doses after nefopam was significantly longer than after placebo.

Adult↗
PubMed1974

Extracellular enzyme from Myxobacter AL-1 that exhibits both beta-1,4-glucanase and chitosanase activites.

An enzyme that has both beta-1,4-glucanase and chitosanase activities is characterized. Evidence for homogeneity was obtained from electrophoresis and sedimentation velocity studies; only one N-terminal amino acid, valine, was found. Results of denaturation studies showed that beta-1,4-glucanase and chitosanase activities decreased at equal rates. With carboxymethylcellulose as the substrate, a K(m) of 1.68 g of carboxymethylcellulose per liter of solution and a V(max) of 2.20 x 10(-9) mol/min were found. With chitosan (the beta-1,4-polymer of glucosamine) as the substrate, a K(m) of 0.30 g of chitosan per liter of solution and a V(max) of 0.75 x 10(-9) mol/min were found. A pH optimum of 5.0 was found for beta-1,4-glucanase activity, and pH optima of 5.0 and 6.8 were found for chitosanase activity. beta-1,4-Glucanase activity had a temperature optimum of 38 C, and chitosanase activity had a temperature optimum of 70 C. Chitosan stabilized both enzyme activities at 70 C. Cellotriose was the smallest polymer capable of hydrolysis. Glucosamine was released by action of the enzyme upon cell wall preparations of several fungi.

Bacterial Proteins↗