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Biomedical subjects

M C Meyer

Publications and source records attributed to M C Meyer.

113 records · Page 7Linked to original sources
PubMedDate not supplied

Serious bioavailability problems with a generic prolonged-release quinidine gluconate product.

A recently marketed prolonged-release quinidine gluconate tablet was compared with the innovator's tablet in a single-dose bioavailability study with 12 healthy male subjects. The extent of absorption of quinidine from the new marketed product was only 50 per cent of the innovator's product. This finding, as well as projections of steady-state plasma concentrations to be expected during multiple-dose administration, indicated a bioequivalence problem with medically significant implications. The data obtained in this study resulted in a Class I recall of the less completely absorbed product by the U.S. Food and Drug Administration.

Adult↗
PubMedDate not supplied

Chloramphenicol dosage and pharmacokinetics in infants and children.

Twenty infants and children receiving intravenous chloramphenicol were studied to examine the pharmacokinetics of the parent compound and its precursor, the succinate ester (CAP-S). Plasma samples were obtained just prior to a 30-minute infusion of chloramphenicol succinate, immediately after or 30 minutes after infusion, and 90, 210, and 330 minutes after infusion. Complete 6-hour urine collections were obtained during 11 studies. Plasma and urine were assayed for chloramphenicol and its succinate ester by high-performance liquid chromatography. Peak plasma concentrations ranged from 11.0 to 51.1 micrograms/ml on doses of 50 to 100 mg/kg/day and were higher in the youngest age group. The elimination half-life of chloramphenicol averaged 4.0 hours. Multilinear regression analysis demonstrated an excellent relationship between body surface area, trough plasma chloramphenicol concentration, and total body chloramphenicol clearance. The hydrolysis of succinate ester to free chloramphenicol may delay the peak free concentration, and its renal elimination (average 21 per cent of the dose administered) significantly affects chloramphenicol pharmacokinetics. The clearance of chloramphenicol exhibited enzyme saturation kinetics in one patient studied at two different doses. Dosage adjustments of intravenous chloramphenicol in children must be made in relation to the trough chloramphenicol plasma concentration, renal elimination of CAP-S, and possible saturation of chloramphenicol metabolism.

Adolescent↗
PubMedDate not supplied

Utilization-focused evaluation: evaluating the effectiveness of a hospital nursing orientation program.

Providing comprehensive orientation programs that prepare nurses for their role as staff nurses is an integral aspect of retention. Therefore, it is vital that staff development educators assess the effectiveness of their nursing orientation programs. In this article, the authors employ a utilization-focused evaluation format to assess a nursing orientation program and, based on the results, offer recommendations for strengthening such programs.

Attitude of Health Personnel↗
PubMedDate not supplied

Flow decreases myogenic reactivity of mesenteric arteries from pregnant rats.

OBJECTIVE: To determine whether pregnancy alters the response of small mesenteric arteries to increased pressure (myogenic reactivity) and flow. METHODS: Mesenteric arteries (300 microns) from cycling nonpregnant (NP, n = 6) and late pregnant (20 days, LP, n = 6) Sprague-Dawley rats were dissected and mounted on an arteriograph system designed for the precise measurement of pressure and flow. Myogenic reactivity was measured as the percentage constriction after a pressure increase to 75 mmHg in the absence and presence of flow (60 microL/minute). RESULTS: In the absence of flow, there was no difference in myogenic reactivity in arteries from NP versus LP animals (NP, 8.4 +/- 1.4%; LP, 11.0 +/- 1.6%; not significant). In the presence of flow, myogenic reactivity was decreased in arteries from LP rats, but was unchanged in arteries from NP rats (NP, 13.2 +/- 1.1%; LP, 2.5 +/- 2.9%; P < .05). The differential group effect appeared to result not from differences in arterial response to changes in pressure or flow alone, but rather from the interaction between pressure and flow. CONCLUSION: These results suggest that pregnancy alters the interaction of the physical forces of pressure and flow on the arterial wall in a manner consistent with decreased vascular resistance.

Animals↗