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Biomedical subjects

K A Conrad

Publications and source records attributed to K A Conrad.

60 records · Page 4Linked to original sources
PubMedDate not supplied

Relationship between total body clearance of caffeine and urine flow rate in elderly men.

The total body clearance (CL), renal clearance (CLR), and nonrenal clearance (CLNR) of caffeine from plasma were determined following the intravenous administration of caffeine (4 mg kg-1) to ten healthy men (aged 66-86 years) on three separate occasions. Positive correlations were observed between CL and urine flow rate (UFR), between CLR and UFR, and between CLNR and UFR (r = 0.8947, p = 0.0002; r = 0.8832, p = 0.0003; and r = 0.8920, p = 0.0002, respectively). Previous studies have established similar relationships between CLR and UFR for caffeine and its initial dimethylxanthine metabolites; theophylline, theobromine, and paraxanthine. A relationship between CL and UFR has not been reported previously.

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PubMedDate not supplied

The influence of sucralfate on ibuprofen absorption in healthy adult males.

Sucralfate (Carafate) is a new anti-ulcer agent the effects of which are mediated locally in the gastrointestinal tract. The use of this compound in conjunction with ulcerogenic drugs such as ibuprofen may represent a means of reducing gastrointestinal irritation. Combined oral therapy, however, requires evaluation of a potential interaction in absorption between those agents. The purpose of this study was to examine the influence of sucralfate coingestion on ibuprofen absorption. Twelve normal, healthy male subjects ingested a single oral 400 mg dose of ibuprofen alone or with sucralfate given as 1 g doses four times a day for 2 days prior to and during the study. Ibuprofen serum concentrations were measured for 12 hours following dosing. Parameters associated with rate of absorption (i.e. Cmax, tmax, Ka) were significantly altered in the presence of sucralfate (p less than 0.05). In contrast, the relative bioavailability of ibuprofen was not significantly different between treatments (p greater than 0.05). Therefore, sucralfate does not alter the extent of ibuprofen absorption and would not be expected to change the response to that anti-inflammatory agent.

Administration, Oral↗
PubMedDate not supplied

Comparison of the inotropic and chronotropic effects of metoprolol and propranolol.

The cardiovascular responses to intravenous doses of isoproterenol were measured in eight male volunteers before and during administration of 50 mg metoprolol, orally every 6 hours and 40 mg propranolol, orally every 6 hours for a total of five doses. The dose of isoproterenol required to produce an increase in heart rate of 25 beats/min (the ID25) was 2.0 +/- 1.4 microgram before beta blockade, 6.2 +/- 4.4 microgram during metoprolol, and 44.4 +/- 12.0 microgram during propranolol administration. Similar changes in diastolic blood pressure, QS2I, preejection period, and preejection period/left ventricular ejection time ratio occurred at the ID25 during treatment with both metoprolol and propranolol. In volunteers, propranolol produces a much more intense blockade of the inotropic and chronotropic effects of isoproterenol than does metoprolol.

Adult↗
PubMedDate not supplied

Once- and twice-daily nitrendipine in patients with hypertension and noninsulin-dependent diabetes.

One hundred and six patients with uncomplicated mild to moderate essential hypertension received nitrendipine 10 mg twice a day or 20 mg once a day in a double-blind, randomized design. At the end of the dosing interval, supine and standing blood pressures were lowered 6/4 and 6/3 mm Hg respectively with the former regimen, and 2/3 mm Hg with the latter. In 10 patients, blood pressure variability through the dosing interval was not increased by nitrendipine 10 mg twice daily, but in another 10, 20 mg daily increased the variability by 28% compared to placebo. Significantly more patients had adverse effects with 20 mg daily than 10 mg twice daily; and both regimens caused more side effects than placebo. In 20 patients, serum glucose levels did not change significantly during treatment with nitrendipine, but in 10 of those with noninsulin-dependent diabetes, the range of maximum plasma insulin in response to a high-carbohydrate meal was 7 times as great during treatment with nitrendipine as it was during treatment with placebo. Nitrendipine lowers blood pressure when given once or twice daily, but twice-daily administration appears to be better tolerated.

Adult↗
PubMedDate not supplied

Leptomeningeal carcinomatosis presenting as eosinophilic meningitis.

The case of a 67-year-old man with underlying carcinomatous meningitis who presented with meningismus and cerebrospinal fluid (CSF) eosinophilia is reported. CSF eosinophilia can reflect a number of underlying conditions; however, carcinomatous meningitis is not generally considered. In this case, studies for bacterial, fungal and parasitic agents were negative. Cytologic examination of a lumbar puncture specimen revealed malignant epithelial cells in an inflammatory background. When unexplained eosinophilia is found in the CSF, a thorough search for coincident meningeal carcinomatosis should be undertaken.

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