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Biomedical subjects

I K Tan

Publications and source records attributed to I K Tan.

At least 55 records · Page 3Linked to original sources
PubMed1980

The use of reference values.

Reference values on concentrations of chemical components in body fluids/tissues serve as indispensable guides for the interpretation of results of biochemical investigations. They provide the criteria necessary for deciding if laboratory results obtained on patients indicate the presence of pathological states or abnormal metabolism. However, in order for reference values to fulfill their expected function, their preparation must take into account the multitude of factors that are now known to have influence on their magnitude and distribution. Ignorance of the effect of such factors can lead to misuse of reference values or preparation of reference data which are of limited use and sometimes misleading. On the other hand, it must be emphasised that even when comprehensive sets of reference values are available, it is necessary to take into consideration all relevant clinical information, including treatment and other diagnostic procedures on the patient before attempting interpretation of any laboratory data. In view of the increasing number of factors that can affect laboratory results, the clinical chemist has an increasingly important role in assisting his clinical colleagues in the interpretation of results and ensuring the intelligent and proper use of reference values for patient diagnosis and management, through comprehensive reporting and education.

Chemistry, Clinical↗
PubMed1979

An assessment of four methods for the assay of amylase activity.

This paper describes an investigation carried out to select a reagent kit for amylase assay to replace the Wohlgemuth method currently in use in our laboratory. The following four commercial kits were assessed: Amylochrome, Phadebas, DyAmyl-L and Amylotube. The results showed that the first three kits which employed chromogenic substrates gave better reproducibility than the Amylotube kit which used plain starch substrate and the starch-iodine reaction. Results obtained with the former methods correlated well with one another but poorly with results obtained with the latter method. Various considerations given for the recommended use of the Amylochrome method are discussed.

Amylases↗
PubMed1978

Evaluation of the Harleco Micro CO2 system for measurement of total CO2 in serum or plasma.

In the Harleco Micro CO2 System a volumetric procedure is used to measure total CO2 content in a small volume (0.10 ml) of serum or plasma. CO2 gas is released by mixing specimen and acid, either manually or with a "Micro CO2 Shaker." Within-batch CV's by manual and machine shakings were, respectively, 7.7 and 5.6% for a total CO2 value of 8 mmol/liter, decreasing to 2.0 and 1.4% for a value of 45 mmol/liter. Between-batch CV's were 8.0 and 7.1% at low total CO2, decreasing to 2.4 and 2.0% at high total CO2. Measurements were linear for values from 5 to 60 mmol/liter. Analytical recoveries at low and high concentrations were 97.7 to 98.9%. Correlation coefficients for results obtained with the Technicon "SMA Plus" autoAnalyzer and the Radiometer ABL 1 blood gas analyzer were 0.992 and 0.996, respectively. The Harleco Micro CO2 System appears to be a quick, reliable, and inexpensive method for measuring serum or plasma total CO2.

Autoanalysis↗
PubMed1978

Plasma glucose measurement with the Yellow Springs Glucose Analyzer.

The Yellow Springs Glucose Analyzer, a device for the quantitative measurement of glucose concentrations, involves the use of immobilized glucose oxidase, incorporated on a membrane covering a hydrogen peroxide sensor. Operation of the instrument is simple. After an initial calibration, 25 microliter of plasma is injected into a reaction chamber. At 45 s a digital result for glucose is displayed. The within-batch coefficient of variation for the method is 1.2% or less for glucose concentrations of 0.94 to 3.98 g/liter. The between-batch coefficient of variation is 5.8% or less for glucose concentrations of 0.29 to 2.91 g/liter. Concentration and readout are linearly related to at least 4.6 g/liter. Analytical recoveries ranged from 100 to 102%. Carry-over was negligible. Values for glucose concentration obtained with the instrument compared well (r = 0.997) with those obtained with the Beckman Glucose Analyzer.

Autoanalysis↗
PubMed1976

Pseudohypoparathyroidism associated with cri du chat syndrome.

A case is reported in which features of pseudohypoparathyroidism were found in association with the cri du chat syndrome. This association may throw some light on the localization of the chromosomal abberration which underlies pseudohypoparathyroidism, since deletion of the short arm of chromosome 5 has been clearly established in the cri du chat syndrome.

Adolescent↗
PubMed1976

Elevated serum enzymes in patients with wasp/bee sting and their clinical significance.

Seventeen patients who had been admitted to hospital for wasp/bee sting were studied. Mild pyrexia was encountered in 7 patients, rash/urticaria in 3, angioneurotic oedema in 2, oliguria in 2, microscopic haematuria and albuminuria in 3, transient hypotension in 1. However, there were frequent elevations of serum glutamic-oxaloacetic transaminase (9 out of 17 patients), serum creatine phosphokinase (14 out of 17 patients) and serum lactate dehydrogenase (8 out of 14 patients), indicating presence of damage to muscle fibres. This was confirmed by the histological findings of a muscle-biopsy from the most severe case. Elevation of serum glutamic-pyruvic transaminase was found in 6, and elevation of serum isocitrate dehydrogenase in 5 out of 14 patients, suggesting presence of liver damage. The above enzyme elevations appeared short-lived except in the clinically most severe patient (case 9) who developed acute tubular necrosis. All patients except the latter suffered no clinical sequelae and there was no correlation between their clinical condition and the presence or degree of elevations of serum enzymes.

Adolescent↗
PubMed1976

Serum urea analysis using the Beckman BUN Analyzer.

A new instrument, the Beckman BUN Analyzer, has been produced for the estimation of urea in microvolume (0-01 ml) of serum or plasma. It requires only a simple two-point calibration for standardization and is suitable for a range of urea levels from zero to 70 mmol/l. The test procedure is simple. After the initial calibration the test sample is injected into the testing chamber and a digital result of the urea concentration is displayed. Serum urea measurements made by this method compared well with those obtained by the Technicon AutoAnalyzer method over the entire working range. The within-batch coefficient of variation of the method is 5-5%, and less at urea levels of 11 to 44 mmol/l. The between-batch coefficient of variation of the method is 6-9%, and less at urea concentrations of 10 to 47 mmol/l. The BUN Aanalyzer method is a quick and reliable alternative to conventional laboratory methods for serum or plasma urea estimation and is especially useful for urgent investigations of both adult and paediatric patients in the hospital wards and at the outpatient clinics.

Blood Chemical Analysis↗
PubMed1975

A new colorimetric method for the determination of NADH/NADPH dependent glutathione reductase in erythrocytes and in plasma.

A simple and rapid colorimetric method for the assay of erythrocyte and plasma glutathione reductase (GR) activity is described. The method is based on the colorimetric measurement of reduced glutathione (GSH) (1) produced when the enzyme is incubated with oxidised glutathione (GSSG) in the presence of either reduced nicotinamide adenine dinucleotide (NADH) or reduced nicotinamide adenine dinucleotide phosphate (NADPH). Results of investigations on the effects of substrate and coenzyme concentrations, pH, EDTA, sodium/potassium chloride, and time, on enzyme activity are presented. Erythrocyte and plasma NADH-GR and NADPH-GR activities in 100 healthy blood donors, and 85 cord blood samples and plasma NADH-GR and NADPH-GR levels in patients with various disease conditions are given.

Colorimetry↗