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G Richards

Publications and source records attributed to G Richards.

173 records · Page 10Linked to original sources
PubMedDate not supplied

Application of Cusum techniques to the routine monitoring of analytical performance in clinical laboratories.

Quality control data from a radioimmunoassay of progesterone are analysed. The measurements are found to have a lognormal distribution. A likelihood analysis of the change-point is described. Some rival continuous inspection schemes are compared and it is pointed out that more efficient schemes than Shewhart's can be implemented in clinical laboratories with the aid of a computer.

Chemistry, Clinical↗
PubMedDate not supplied

Dose-interpolation of immunoassay data: uncertainties associated with curve-fitting.

Estimates of analyte concentrations, obtained by immunoassay, have error distributions which are generally underestimated. Better estimates, which take into account the distribution of the response metameter of the calibration curve and uncertainties associated with the location of the fitted curve, have been obtained by computer simulation using practical immunoassay data. The increased use of curve-fitting software in automated immunoassay equipment has prompted the investigation of reported analyte concentration distributions for three commonly used functions, namely the logit-log, the 4-parameter logistic and the four-parameter Amersham models. The stimulation model is of potential value for a variety of situations.

Biometry↗
PubMedDate not supplied

A comparative pharmacokinetic study of intravenous and intramuscular midazolam in patients with epilepsy.

The pharmacokinetics of midazolam, a water soluble 1,4-benzodiazepine, has been studied in 12 patients (11 male, 1 female; age range 19-57 years) with epilepsy. All patients were taking hepatic enzyme inducing antiepileptic drugs (AEDs) on a regular basis. Midazolam (5 mg) was administered intravenously and 1 week later midazolam was administered intramuscularly, the dose used being dependent on the sedative response to the intravenous dose (10 mg, n = 2; 7 mg, n = 8; 5 mg, n = 2). Serial blood samples were collected at timed intervals for 5-7 h. After intravenous administration initial distribution was rapid with a mean half-life (t 1/2 alpha) of 0.06 +/- 0.03 h followed by a terminal half-life (t 1/2 beta or gamma) of 1.5 +/- 0.3 h. Volume of distribution was 0.62 +/- 0.27 l/kg. After intramuscular administration midazolam was rapidly absorbed with peak serum concentrations achieved at 25 +/- 23 min. Two patients showed delayed absorption. Mean terminal half-life was 2.8 +/- 1.7 h. The absolute bioavailability of intramuscular midazolam was calculated in 11 patients as 87 +/- 18%. Sedation was rapid (less than 1-2 min) but transient (7-75 min) after intravenous and slower (2-30 min) and for a longer period (20-120 min) after intramuscular administration. Since intravenous administration of AEDs including diazepam is not always feasible in status epilepticus there are obvious advantages in having an effective intramuscular formulation. Our data suggest that midazolam may be such a drug.

Adult↗