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Biomedical subjects

A Racine-Poon

Publications and source records attributed to A Racine-Poon.

7 recordsLinked to original sources
PubMed1991

Estimation of relative potency with sequential dilution errors in radioimmunoassay.

Sequential dilution is a very common procedure in radioimmunoassay, in which the dilution error will be accumulated from the highest to the lowest concentration. A simulated example in relative potency determination is used to demonstrate the potentially wrong conclusion that can be drawn, when the dilution error is not properly included in the model. A Bayesian method is used and an alternative approximation via maximum likelihood is proposed. An alternative experimental design is recommended to increase the precision of the inference.

Bayes Theorem↗
PubMed1987

A two-stage procedure for bioequivalence studies.

A two-stage experimental procedure for bioequivalence studies is proposed. The procedure is based on the idea that information from a first-stage experiment can be used to form a predictive distribution for the outcome of a second-stage experiment, thus permitting an assessment of the probability of a successful overall outcome. A systematic numerical study of a variety of possible strategies results in the identification of procedures that lead to substantial increases in efficiency compared with single-stage studies.

Biometry↗
PubMed1985

Concentration-effect relationship of oxprenolol in healthy volunteers: a retrospective analysis.

A mathematical model describing the relationship between plasma concentrations of oxprenolol and submaximal-exercise heart rates has been developed on the basis of data available from 34 healthy volunteers. This relationship, which is exponential in type, is consistent with the 'law of diminishing returns', and is independent of the pharmaceutical formulations used; it appears to be established instantaneously, and is not modified by repeated drug administration over 8 days. At oxprenolol concentrations of 190-250 ng/ml, between half and three-quarters of the subjects investigated reached 90% of their estimated maximum levels of beta-adrenoceptor blockade.

Delayed-Action Preparations↗
PubMed1985

Pre-dosing plasma concentrations and beta-adrenoceptor blocking effects during repeated once daily dosing with 160 mg sustained-release propranolol (Inderal LA) and 16/260 oxprenolol Oros to healthy volunteers.

Plasma drug concentrations and attenuations in sub-maximal exercise tachycardia were measured in six healthy subjects 24 h after the third and fourth doses of Inderal LA and 16/260 oxprenolol Oros administered once daily. Both drugs significantly reduced exercise heart rates relative to the placebo response, at both observation times. The mean percentage reductions on the third and fourth days were, respectively, 15.7 and 11.6% for Inderal LA compared with 18.1 and 12.2% for 16/260 oxprenolol Oros. The differences between formulations were not statistically significant. The mean plasma concentrations at 24 h on the third and fourth day were 119 and 101 ng/g for oxprenolol and 16.2 and 15.8 ng/g for propranolol.

Adult↗
PubMed1985

A Bayesian approach to nonlinear random effects models.

Nonlinear random effects models are considered from the Bayesian point of view. The method of analysis follows closely that of Lindley and Smith (1972, Journal of the Royal Statistical Society, Series B 34, 1-42). The numerical method is related to the EM algorithm.

Analysis of Variance↗