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Biomedical subjects

M L Hyneck

Publications and source records attributed to M L Hyneck.

30 records · Page 2Linked to original sources

Cimetidine clearance during intermittent and chronic peritoneal dialysis.

A case report evaluating the clearance of cimetidine during intermittent peritoneal dialysis and chronic ambulatory peritoneal dialysis is presented. A 50-year-old white man with end-stage renal disease using chronic ambulatory peritoneal dialysis was hospitalized with uremic pericarditis. He was treated with indomethacin and aggressive intermittent peritoneal dialysis. Cimetidine 300 mg every 12 hours was prescribed for ulcer prophylaxis. After taking cimetidine for seven days, the clearance of cimetidine during intermittent peritoneal dialysis was evaluated by collecting blood and dialysate samples during a four-hour dialysis period. The patient was discharged using chronic ambulatory peritoneal dialysis. Cimetidine 300 mg every 12 hours was continued. One week after discharge, the clearance of cimetidine during a four-hour dwell period of chronic ambulatory peritoneal dialysis was measured. Cimetidine clearance was approximately 4 ml/min for both intermittent and chronic ambulatory peritoneal dialysis. Clinically unimportant quantities of cimetidine were removed by intermittent and chronic ambulatory peritoneal dialysis. The need for supplemental doses of cimetidine during peritoneal dialysis is not supported.

Cimetidine↗

Effect of pH on the stability of heparin in 5% dextrose solutions.

The effect of pH and time on the stability of heparin sodium in dextrose 5% in water (D5W) injection and in dextrose 5% in 0.45% sodium chloride injection was studied. Admixtures of heparin sodium 5,000 units/250 ml were tested after 0, 10, 20 and 30 minutes and 1, 2, 6, 12 and 24 hours of storage at room temperature. The pH of the carrier solutions was adjusted to 2, 4 or 9 prior to adding the heparin sodium. Heparin activity was measured using a thrombin clotting time assay. Samples were tested for pH changes at the same times. No substantial changes in heparin activity over the 24-hour period occurred with any of the pH-adjusted solutions. The pH of the heparin-D5W admixtures remained constant over time. The two carrier solutions, over a pH range of 2 to 9, appear to be suitable vehicles for heparin sodium.

Biological Assay↗

A comparative study on the genetic effects of hycanthone and oxamniquine.

Oxamniquine (UK-4271; 6-hydroxymethyl-2-isopropylaminomethyl-7-nitro-1,2,3,4-tetrahydroquinoline) is a new schistosomicidal agent currently undergoing clinical investigation in South America. Essentially a complete cure rate against Brazilian Schistosoma mansoni has been seen in adults with a single im dose of 7.5 mg/kg or a single oral dose of 15 mg/kg. These regimens were tolerated without significant toxicity. To assess its mutagenic potential, oxamniquine was examined in a battery of genetic tests designed to detect mutations at the gene and chromosome levels. For comparative purposes, hycanthone, a schistosomicide with extensively studied mutagenic properties, was evaluated in a similar series of tests. Point mutations were measured in a series of histidineless auxotrophs of Salmonella typhimurium in direct plate and host-mediated assays. Gross chromosomal aberrations were assessed in human leucocyte cultures and in bone marrow preparations from drug-treated mice. Effects on germ cells were tested in the dominant-lethal assay. Hycanthone showed significant mutagenic activity in the direct bacterial tests and the in vivo and in vitro cytogenetic assays. No response was detected in the host-mediated or dominant-lethal assays. On the other hand, oxamniquine produced no drug-related mutagenic effects in the cytogenetic, host-mediated, or dominant-lethal tests at doses up to 150 mg/kg administered parenterally. Oxamniquine produced a weak response in the frameshift mutant, TA1538, of Salmonella typhimurium in direct plate tests with and without liver microsomal enzymes. However, this response was achieved only by using a concentration of compound which was several orders of magnitude higher than that required to produce a similar response to hycanthone.

Animals↗

Comparative bioavailability study of two tablet formulations of cimetidine.

A two-way crossover bioavailability study of two commercial cimetidine formulations was performed on 24 healthy male volunteers. Drug was administered after an overnight fast and plasma samples were withdrawn periodically for 12 h. Urine was collected throughout the study period. Results indicated that the two formulations were bioequivalent since no statistically significant difference in means was detected for any of the parameters studied. Extensive interpatient variation in cimetidine blood concentration was observed during both treatments.

Administration, Oral↗

Effect of cimetidine on serum uric acid concentration.

The effect of cimetidine therapy on serum uric acid concentration was studied in four healthy men with normal renal function. Beginning four days before the 16-day study, subjects were permitted no beverages containing caffeine or alcohol and no medications and were placed on a weight-maintenance, isocaloric, purine-free 152-meq-sodium diet. On days 1-12 one cimetidine 300-mg tablet was taken four times daily; on days 13-16 no cimetidine was taken. On each study day, serum uric acid and creatinine and urine uric acid and creatinine concentrations were determined. Daily mean values for serum uric acid, total uric acid excreted, and uric acid clearance were not significantly different from baseline. No significant change occurred in creatinine excreted or creatinine clearance. Cimetidine administration to healthy men with normal renal function did not significantly affect serum uric acid concentration or renal clearance of urate.

Adult↗

Accuracy of four methods of home blood glucose monitoring in hemodialysis patients.

The accuracy of four techniques of home blood glucose monitoring in hemodialysis patients was compared. Arterial-venous blood samples were collected from 23 patients undergoing hemodialysis and analyzed for serum glucose concentrations using an automated laboratory method. Capillary-blood glucose concentrations were also determined in each patient by visual readings of the Chemstrip bG and Dextrostix reagent strips and by reflectometer readings of the StatTek Glucose and Dextrostix reagent strips. Readings of glucose concentration obtained by each of the four techniques were compared with laboratory-determined values, and the true and absolute deviations in these values for each technique were recorded. The effect of patient hematocrit on deviations in glucose concentration readings was evaluated by analysis of variance. The mean glucose concentration readings obtained using the visual and reflectometer (Dextrometer) readings of Dextrostix were substantially less accurate than the other two techniques when compared with serum glucose concentrations determined by the laboratory. The StatTek technique gave the smallest mean absolute deviation from laboratory-determined values. No correlation was found between the patient's hematocrit and either the true or absolute deviations in glucose concentrations. The Chemstrip bG and StatTek techniques are reasonably accurate methods for home monitoring of blood glucose concentrations in diabetic patients undergoing hemodialysis.

Blood Glucose↗