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Biomedical subjects

L G Whitby

Publications and source records attributed to L G Whitby.

At least 19 recordsLinked to original sources
PubMed1978

The peak monitor of the Technicon SMAC system.

The peak-monitor software of the Technicon SMAC system has been investigated by experiments designed to test its ability to detect abnormally shaped peaks, deliberately produced by presenting serum samples of inadequate volume for analysis. The software provided by the manufacturer is shown to detect faulty peaks inefficiently, and a set of modified parameters has been identified which greatly improves the performance of the peak-monitor software.

Autoanalysis↗
PubMed1977

Activities of bone and liver alkaline phosphatases in serum in health and disease.

A heat-inactivation method for determining absolute activities of liver and bone alkaline phosphatases in serum has been applied extensively in routine diagnosis. Values for each isoenzyme in healthy individuals of different ages are reported together with results obtained in various diseases. Data from normal subjects show that bone alkaline phosphatase contributes about half the total alkaline phosphatase activity in adults. Liver phosphatase shows a slight increase with age. The method is also able to detect reliably the presence of carcinoplacental isoenzymes.

Adolescent↗
PubMed1977

Marking systems for multiple choice examinations.

This article discusses the advantages and disadvantages of no penalty and penalty marking systems. It also reviews ways in which examiners have attempted to correct for guessing by candidates, and the use of 'don't know' options and confidence-weighting for attempting to assess the degree of certainty that candidates attach to their answers.

Educational Measurement↗
PubMed1975

A simplified heat-inactivation method for investigating alkaline phosphatase isoenzymes in serum.

A method is described for the determination of the percentage of liver alkaline phosphatase in serum samples in which measurements of residual activity are made after incubating the samples for 15 and 25 min at 56 degrees C. This method has the advantage of taking into account quantitative variations in the heat stability characteristics of liver alkaline phosphatase from one sample to another, in contrast to methods in which only a single period of exposure to 56 degrees C is employed.

Alkaline Phosphatase↗
PubMed1975

Analysis of heat inactivation curves of alkaline phosphatase isoenzymes in serum.

The course of the decline in alkaline phosphatase activity during exposureof serum samples to a temperature of 56 degree C can be resolved into two phases. These represent the exponential decay of an enzyme component with an average half-inactivation time of 112 seconds and of a second component with an average half-inactivation time of 456 seconds. The more rapid fall is due to inactivation of bone alkaline phosphatase and the slower to inactivation of liver and, when present, intestinal phosphatases. The half-inactivation times of the different enzyme species show considerable variation from one serum sample to another. The implications of this variation for methods of estimating the relative proportions of alkaline phosphatase isoenzymes by selective inactivation procedures are discussed.

Alkaline Phosphatase↗
PubMed1973

Routine operation of an Elliott 903 computer in a clinical chemistry laboratory.

Experience gained in the last four years concerning the capabilities and limitations of an 8K Elliott 903 (18-bit word) computer with magnetic tape backing store in the routine operation of a clinical chemistry laboratory is described. Designed as a total system, routine operation has latterly had to be confined to data acquisition and process control functions, due primarily to limitations imposed by the choice of hardware early in the project. In this final report of a partially successful experiment the opportunity is taken to review mistakes made, especially at the start of the project, to warn potential computer users of pitfalls to be avoided.

Chemistry, Clinical↗
PubMed1972

The role of operational research in clinical chemistry.

This paper begins with a critical examination of the published account (Carruthers, 1970) of a pioneering study of simulation in a clinical chemistry laboratory. It next considers the basic requirements for the formal mathematical description of such a laboratory: these include the setting of criteria, the resource and input variates, and the definition of success by means of criterion variates. Investigation of criterion variates can be by direct measurement, or by a theoretical approach which may include simulation. The aims of simulation are discussed and an attempt to simulate the operation of a large clinical chemistry laboratory is described. The difficulty of constructing an overall measure of efficiency is considered in relation to improving performance within an existing framework, to evaluating new equipment such as computers on-line to laboratory apparatus, and to inter-laboratory comparisons of performance. It is concluded that complex operational research techniques, including simulation, have little to offer at least for the present, and may even lead to misleading conclusions.

Chemistry, Clinical↗
PubMed1971

Biochemical screening programme in general practice: a clinical follow-up.

Follow-up studies of findings obtained during a short programme of biochemical screening conducted on 1,041 patients attending their general practitioners in January 1967 showed that this yielded 64 results that led to a change in diagnosis or method of treatment. These results were obtained in 57 patients (5.5% of patients screened), whereas only 15 abnormal results would have been revealed on 14 of the 1,041 patients if the tests performed had been restricted to those requested on the basis of clinical features. Hence a screening programme can make an important contribution to the recognition of otherwise unsuspected disease.

Adult↗