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Biomedical subjects

E Burgess

Publications and source records attributed to E Burgess.

49 records · Page 3Linked to original sources
PubMed1989

Propafenone disposition in renal insufficiency and renal failure.

The pharmacokinetics of a single intravenous dose of propafenone were studied in subjects with normal renal function (n = 5), renal insufficiency (n = 5), and renal failure (n = 3). No difference in central volume of distribution, total ischemic clearance or terminal half-life existed. None of the pharmacokinetic parameters examined correlated to creatinine clearance. Within the confines of the small number of patients studied, there does not appear to be any effect of renal insufficiency or failure on single-dose propafenone disposition.

Adult↗
PubMed1988

Oral flecainide pharmacokinetics in patients with impaired renal function.

The pharmacokinetics of flecainide acetate were studied in 20 patients with varying degrees of renal impairment following a single oral dose. The patients were divided into two groups, on the basis of renal creatinine clearance (CLCR), for statistical and kinetic analysis. Patients with a CLCR between 4 and 41 mL/min/m2 were designated group 1 and those below 4 mL/min/m2 or unmeasurable because of lack of urine output were designated group 2. In both groups peak plasma flecainide concentrations, time to peak concentrations, and apparent volume of distribution (Vd) were similar to those reported in healthy subjects with normal renal function. The mean flecainide plasma elimination half-lives from both groups 1 and 2 were longer than those previously reported by several investigators in normal subjects. Nine patients in group 1 and seven patients in group 2 had half-lives within the range reported in healthy subjects. Therefore, CLCR alone is not a good predictor of plasma elimination half-life following a single oral dose of flecainide. Although renal clearance of flecainide is significantly reduced in end-stage renal disease (ESRD), total plasma clearance of flecainide (CLflec) was not reduced to the same degree, although there was a significant, modest correlation with CLCR. Less than 1% of the administered oral dose of flecainide was removed during hemodialysis. The relationship between dosage and plasma elimination half-life in patients with ESRD needs further study to evaluate possible dose-dependent kinetics.

Administration, Oral↗
PubMed1988

Pilot study of cyclosporin A in patients with symptomatic primary biliary cirrhosis.

The purpose of this pilot study was to determine whether daily administration of cyclosporin A to symptomatic patients with primary biliary cirrhosis for 1 yr would lead to a significant and sustained improvement in liver enzyme abnormalities. Twelve adult patients (11 female, 1 male; aged 52.6 +/- 8.9 yr, mean +/- SD) with serologic and histologically defined primary biliary cirrhosis were randomized to receive either oral cyclosporin A or vehicle placebo. Cyclosporin A was administered at sufficient dosages to maintain serum radioimmunoassay trough levels between 100 and 200 ng/ml (starting dosage, 2.5 mg/kg.day). After 1 yr of therapy, significant changes from pretreatment values were seen only in recipients of cyclosporin A. These included a 37% decrease in mean serum alkaline phosphatase and a 43% decrease in gamma-glutamyltransferase (controls +3% and -14%, respectively). Mean serum bilirubin and albumin levels and prothrombin times remained unaltered in the two groups, as did the extent of inflammation and fibrosis and the histologic staging of liver biopsy specimens. Although mean serum creatinine levels increased by 51% in recipients of cyclosporin A (+2% in controls), there were no associated changes in diastolic blood pressure or creatinine clearance values. Other side effects including thrombocytopenia, hirsutism, headaches, tremor, and parasthesiae were common in the treated group but not of sufficient severity to warrant adjustment in the dosage or discontinuation of therapy. The observed changes in hepatic, renal, and hematologic tests tended to return to baseline after discontinuation of therapy. Two patients, both placebo recipients, died of liver failure during the study period. The results of this study indicate that in symptomatic primary biliary cirrhosis, cyclosporin A administration is associated with a significant improvement in cholestatic liver enzyme abnormalities that persists for the duration of therapy. A progressive rise in serum creatinine levels and a high incidence of side effects raise concerns regarding the long-term safety of this agent in primary biliary cirrhosis.

Adult↗
PubMedDate not supplied

Charcoal hemoperfusion for theophylline overdose: case report and proposal for predicting treatment time.

Charcoal hemoperfusion is effective in the treatment of theophylline overdose. Estimation of the time required for charcoal hemoperfusion has been based on personal experience and judgment. We used pharmacokinetic data from a patient and from case reports to generate a formula for predicting treatment time. Pharmacokinetic parameters were calculated using model-independent analysis of concentration-time curves from two treatments of charcoal hemoperfusion. These values were compared with published data and incorporated into a formula that was derived from the elimination rate constant to estimate treatment time of charcoal hemoperfusion: Time (min) = (ln conci-ln concd)/0.0057, where the concentration of theophylline is in mumol/L. The formula may be valid in patients in whom the serum theophylline concentration is less than or equal to 516 mumol/L or 92 mg/L. It may be used as a guide to estimate the length of charcoal hemoperfusion in the treatment of theophylline toxicity. Its validation requires implementation and evaluation in future cases.

Adult↗
PubMedDate not supplied

Renal effects of peptic ulcer therapy.

Drugs used in the treatment of peptic ulcer disease may interact with the renal system in a variety of ways. Since many agents are eliminated by renal excretion, clearance of these agents may be reduced and half-life extended in the presence of renal insufficiency. The histamine H2-receptor antagonists may interfere with renal tubular excretion of creatinine and cationic drugs, resulting in elevated serum concentrations and reduced renal clearance. The prostaglandin E1 analogue misoprostol is used as a cytoprotective agent but has renal effects. The renal effects differ between systems studied. In the rat, misoprostol reduces cyclosporin-induced renal tubular toxicity, whereas in humans it has been shown to attenuate renal allograft rejection. Sucralfate is the aluminium salt of sucrose octasulfate. It permits the absorption of aluminium in amounts similar to aluminium-containing antacids, and toxicity has been demonstrated in the presence of renal insufficiency. Bismuth compounds are used increasingly to treat peptic ulcer disease, and bismuth toxicity has been described in association with renal insufficiency. Aluminium-, calcium- and magnesium-containing antacids are used as oral phosphate binders in patients with renal insufficiency in addition to their usual indications. Cation absorption and accumulation with all of these antacid preparations has been described and may lead to toxicity.

Anti-Ulcer Agents↗
PubMedDate not supplied

Inhibition of glycosylphosphatidylinositol (GPI) phospholipase D by suramin-like compounds.

A number of proteins are found attached to the plasma membrane of mammalian cells by a glycosylphosphatidylinositol (GPI) anchor that can be cleaved by GPI specific phospholipase D (GPI-PLD). There are no known specific inhibitors of GPI-PLD. We examined some inhibitors of phosphatidylinositol specific phospholipase C (PI-PLC) for their ability to inhibit human serum and human bone marrow cell GPI-PLD. Azo analogues of suramin were found to be potent inhibitors of GPI-PLD. One compound had an IC50 of 3.7 microM that was 10-fold lower than the IC50 required to inhibit PI-PLC. The azo suramin analogues inhibited cancer cell growth at concentrations similar to those required to inhibit GPI-PLD, and below concentrations required to inhibit growth factor binding. It is possible that inhibition of cell growth might be related to the ability of the compounds to inhibit GPI-PLD.

Cell Division↗