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Biomedical subjects

J Leslie

Publications and source records attributed to J Leslie.

At least 19 recordsLinked to original sources

Hawkinsinuria in two families.

Hawkinsinuria, a disorder of tyrosine metabolism has been documented in two families in the United States, in one of which there was clear evidence of autosomal dominant inheritance. Metabolic acidosis and failure to thrive appear to be confined to infancy. Tyrosyl metabolites and 5-oxoproline are also found only in infancy, while 4-hydroxycyclohexylacetic acid was present only with time. The disease may be detected by organic acid analysis or by staining an electropherogram for sulfur containing compounds.

Acidosis

Ondansetron in the treatment of postoperative nausea and vomiting in ambulatory outpatients: a dose-comparative, stratified, multicentre study.

The safety and efficacy of ondansetron were evaluated in the treatment of postoperative nausea and vomiting. Five hundred patients who experienced nausea or vomiting in the Post-Anaesthesia Care Unit within the first 2 h of recovery were randomized to receive either 1, 4, or 8 mg of ondansetron, or placebo. All patients had undergone ambulatory surgery with general endotracheal anaesthesia. Episodes of emesis, nausea scores, adverse events, vital signs, and laboratory values were assessed before and during the 24 h after study drug administration. Patients were evaluated for the first 2 h in the Post-Anaesthesia Care Unit then followed up for the next 22 h. Complete response was defined as no emetic episodes, no nausea or no rescue anti-emetic medication. For the 0-24 h study period, complete response occurred in only 15% of the placebo group compared to 41%, 47%, and 47% in the 1, 4, and 8 mg ondansetron groups, respectively. Mean nausea scores (scale of 0-10) during the initial observation period (0-2 h) were significantly lower for all doses of ondansetron [2.2 (1 mg), 1.7 (4 mg), and 2.1 (8 mg)] compared to placebo (3.0). The optimal dose of ondansetron for the treatment of postoperative nausea and vomiting was found to be 4 mg. All doses of ondansetron were well tolerated. No clinically significant increases in laboratory parameters or alterations in haemodynamic stability occurred in the ondansetron groups compared to placebo.

Adolescent

Does desmopressin acetate prophylaxis reduce blood loss after valvular heart operations? A randomized, double-blind study.

The effectiveness of prophylactic desmopressin acetate in reducing hemorrhage after cardiopulmonary bypass operations is controversial. We conducted a prospective, randomized, placebo-controlled, double-blind trial to determine its effectiveness and safety in such patients. Eighty-three evaluable patients undergoing valvular heart operations were randomized to receive desmopressin (0.3 microgram/kg) (41) or placebo (42) after cardiac bypass. Demographic characteristics were similar in both groups. There was no significant difference in total 24-hour blood loss between groups (desmopressin 1064.8 +/- 647.1 ml versus placebo 844.4 +/- 507.6 ml; p greater than 0.05), or in the requirement for red blood cell, platelet, or fresh frozen plasma transfusion, or for reexploration for control of hemorrhage. Neither was there a difference in the occurrence of thrombotic complications between groups. Analysis of factor VIII activity, von Willebrand factor, or von Willebrand factor multimers failed to show significant correlations with blood loss or differences between groups except for factor VIII activity, which was significantly higher in the desmopressin group 1 hour after operation than in the placebo group. A detailed comparative analysis of similar trials to determine the reasons for different outcomes suggests that desmopressin should not be used routinely as a prophylactic agent to reduce postsurgical hemorrhage, but that it may be beneficial when used in patients who already manifest excessive bleeding postoperatively.

Blood Loss, Surgical

Circulating free amino acids in Aplysia californica.

1. Questions regarding the availability of free amino acids and their importance as precursors and direct participants in neural functions are essential to our understanding but cannot be answered without basic data. 2. A profile of 22 circulating amino acids was developed for the often studied Aplysia californica.

Amino Acids

Absorption and disposition of colloidal drug delivery systems. I. High-performance liquid chromatographic (HPLC) analysis of a cyclosporin emulsion.

The amount of cyclosporin A in an oil-in-water emulsion drug delivery system was determined by HPLC. The direct extraction and analysis of an intact emulsion were compared to the analysis of a cracked emulsion and an olive oil solution of the drug. The intra- and interday variability for the intact emulsion was less than 10% from 35 to 150 micrograms/ml, with recovery of 94%. Comparison of the assay results obtained with the emulsion and the olive oil solution gave a highly correlated regression line with a small intercept and a slope close to unity. Thus, the direct extraction and HPLC analysis of drugs in emulsions may be a viable approach to evaluate drug content.

Absorption

Transcobalamin II deficiency presenting with methylmalonic aciduria and homocystinuria and abnormal absorption of cobalamin.

An infant with deficiency of transcobalamin II (TCII) presented with virtually complete failure to thrive and life-threatening pancytopenia. Methylmalonic acid and homocystine were found in the urine. The concentration of B12 in the serum was 26 pg/ml. Fibroblasts derived from the patient failed to take up labeled cobalamin in the absence of a source of TCII. Uptake was normal in the presence of TCII. Treatment with parenteral cobalamin reversed the clinical and hematological manifestations of the disease but she developed glossitis when the interval between injections was lengthened. Intestinal absorption of 57Co-cobalamin was less than 1% and remained abnormal when highly purified human intrinsic factor was given along with the labeled B12. Absorption improved when the labeled B12 was given together with rabbit TCII. The data suggest that TCII as well as intrinsic factor is required for transport of cobalamin from the intestine to the blood.

Failure to Thrive

Preliminary trial of 3,4-diaminopyridine in patients with multiple sclerosis.

Ten patients with multiple sclerosis (MS) were enrolled in a preliminary trial of the potassium channel blocker, 3,4-diaminopyridine, to evaluate drug toxicity and pharmacokinetics. The patients were treated with oral 3,4-diaminopyridine, first with increasing single doses up to 100 mg and then with divided dosage for up to 3 weeks. Paresthesias were reported by all patients and abdominal pain was dose limiting in 6 patients. 3,4-Diaminopyridine levels and half-life varied widely from patient to patient. Cerebrospinal fluid levels of 3,4-diaminopyridine were about 10% of those in serum. Neither seizures nor epileptiform changes on electroencephalographic examination occurred. Small reversible improvements in specific neurological deficits were seen on examination in all patients and reversible improvement in visual evoked response latencies were found in 2 patients. These results suggest that further study of 3,4-diaminopyridine in patients with MS is warranted.

4-Aminopyridine

Excretion of hippuric acid during sodium benzoate therapy in patients with hyperglycinaemia or hyperammonaemia.

In patients with non-ketotic hyperglycinaemia and two patients with urea cycle disorders treated with varying doses of sodium benzoate there was linear correlation between intake of benzoate and excretion of hippurate. Patients with non-ketotic hyperglycinaemia excreted significantly more benzoate in the form of hippurate than patients with urea cycle disorders (74 +/- 7.0 vs 41 +/- 3.6%). The plasma concentration of glycine decreased following benzoate treatment only in the patients with non-ketotic hyperglycinaemia. The observed difference between the two groups in the excretion of hippurate seems to support the concept that glycine availability may be limiting in benzoate therapy for some patients.

Amino Acid Metabolism, Inborn Errors

Effects of ascorbic acid in alkaptonuria: alterations in benzoquinone acetic acid and an ontogenic effect in infancy.

The effects of ascorbic acid on the excretion of homogentisic acid and its derivative benzoquinone acetic acid were studied in two adults and three infants. The administration of relatively large amounts of ascorbic acid to the adults was followed by a disappearance of benzoquinone acetic acid from the urine, whereas the level of excretion of homogentisic acid did not change. This could have relevance to the pathogenesis of ochronotic arthritis. In the 4-mo-old infant and the 5-mo-old infant ascorbic acid in the urine may have doubled the amount of homogentisic acid, presumably through an effect on the immature p-hydroxyphenylpyruvic acid oxidase. Dietary reduction of the intake of tyrosine and phenylalanine substantially reduced the excretion of homogentisic acid.

Aged

Relationships between renal function and disposition of oral ciprofloxacin.

The relationships between creatinine clearance (CLCR) and the pharmacokinetics of oral ciprofloxacin were characterized. On the basis of these data, a dosage adjustment strategy, which incorporates the severity of infection and the size and renal function of the patient, was developed. An adaptive (feedback) control algorithm is proposed. A total of 32 subjects (8 normal, 8 anuric, and 16 with CLCR between 0.53 and 4.3 liters/h per 1.73 m2) were given a single 750-mg tablet of ciprofloxacin by mouth. Serial serum and urine samples were collected, assayed by high-pressure liquid chromatography, and comodeled. The population relationship between total apparent ciprofloxacin clearance (CL/f) and CLCR, both measured in liters per hour per 1.73 m2, was CL/f = 2.83 x CLCR + 21.8 (r = 0.69; P less than 0.001). The mean terminal half-life was not significantly related to CLCR but was much more variable in subjects with CLCR less than 3 liters/h per 1.73 m2 (F = 4.8; P less than 0.005). We conclude that patients with CLCR less than 1.2 liters/h per 1.73 m2 should receive two-thirds of the normal daily dose and that the dose interval should not be lengthened.

Administration, Oral

Imipenem coadministered with cilastatin compared with moxalactam: integration of serum pharmacokinetics and microbiologic activity following single-dose administration to normal volunteers.

We administered 1 g of imipenem along with equal amounts of cilastatin (a dehydropeptidase I inhibitor) or 2 g of moxalactam intravenously over a period of 30 min to six volunteers in a crossover manner 1 week apart. The antibiotic concentrations and pharmacokinetics for each drug were determined and integrated with the microbiologic activity by measuring the duration of time that the free drug concentrations remained above the MICs for 90% of 581 clinical isolates and by measuring serum bactericidal activities against organisms which commonly infect granulocytopenic cancer patients. Moxalactam produced serum levels at 1 h after infusion of 99.9 micrograms/ml; these levels were four times greater than the plasma levels of imipenem (22.8 micrograms/ml). The trough (5.5-h) moxalactam serum levels were 10 times greater than those of imipenem (18.5 and 1.7 micrograms/ml, respectively). Essentially all of the imipenem was unbound to protein, whereas 36 to 42% of the moxalactam was unbound. Moxalactam produced free antibiotic concentrations that were above the MIC for 90% of the strains tested for more than 6 h against all of the species tested except Staphylococcus aureus (5.3 h), Enterobacter hafnia (1.6 h), and Pseudomonas aeruginosa (0 h). The imipenem concentrations were above the MIC for 90% of the strains tested for 5.6 h or more against all of the bacteria tested except Proteus spp. and Pseudomonas aeruginosa (4.5 h). The geometric mean peak bactericidal titers from volunteers receiving imipenem were more than 1:8 against all bacteria and were significantly higher than the titers from volunteers receiving moxalactam against S. aureus (1:7.3) and Pseudomonas aeruginosa (1:4.5). These data, in addition to information obtained from animal models, indicate that imipenem is a promising new candidate for carefully controlled clinical trials as a single agent for therapy of serious infections, including empiric therapy for fever in granulocytopenic cancer patients.

Adolescent