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Biomedical subjects

I K Tan

Publications and source records attributed to I K Tan.

At least 19 recordsLinked to original sources
PubMed1992

Serum magnesium, copper, and zinc concentrations in acute myocardial infarction.

This study was carried out to assess the serum levels of magnesium, copper, and zinc after an acute episode of myocardial infarction. Determination of the metal concentrations were carried out on 41 patients with myocardial infarction and 41 healthy controls matched for age and sex. A slight decrease in the mean level of magnesium (P less than .05) was observed in patients (2.0 mg/dl) compared with the controls (2.1 mg/dl). The mean serum copper concentration was significantly higher (P less than .001) in patients (138 micrograms/dl) than in controls (98 micrograms/dl), while the mean serum zinc concentration was significantly lower (P less than .001) in patients (75 micrograms/dl) than in controls (100 micrograms/dl). The differences in serum copper and zinc levels between patients and controls were magnified considerably when the copper/zinc ratios were calculated for both groups (P less than .001). The mean copper/zinc value obtained for patients (1.91) was almost double that for the controls (1.02).

Adult↗
PubMed1991

Growth and the production of penicillins in Penicillium chrysogenum with palm oil and its various fractions as carbon sources.

The utilisation of palm oil and its fractions by Penicillium chrysogenum for growth and penicillin production is strain-dependent. Strain H1107 could utilise crude palm oil, its liquid (palm olein) and solid (palm stearin) fractions and its component fatty acids (oleic, palmitic, stearic and myristic) as the main carbon source; strain M223 could not. Cell-bound lipase activity was higher in H1107 than in M223.

Fatty Acids↗
PubMed1991

Local norms of maternal serum alpha-fetoprotein values in early second trimester: a prelude to a Down's syndrome screening programme incorporating maternal serum alpha-fetoprotein values.

Maternal alpha-fetoprotein in (MSAFP) has recently been proposed for screening of Down's syndrome. This is based on the association of a lowered MSAFP level at a given gestational age in Down's syndrome (DS) pregnancies. Most conventional 'screening' programmes in DS are based on the maternal age alone, selecting older mothers, who are at greater risk of having a DS infant born, for antenatal karyotyping. However, as 75% of DS infants are born to mothers less than 35 years old, a combination of blood tests including MSAFP and maternal age as independent risk factors would screen the younger mothers as a good cost-benefit ratio in selecting the 'at-risk' mothers for karyotyping. In this study, the gestational age was calculated from the first day of the last menstrual period (LMP) as well as from ultrasound cephalometry. The local MSAFP levels follow the same trend at a slightly higher level as those based on clinical evaluation of the Abbot AFP-EIA Monoclonal kits.

Down Syndrome↗
PubMed1990

Use of computers in quality assurance of laboratory testing.

Implementation of comprehensive internal quality control programmes and participation in external quality assessment schemes to monitor analytical performance of laboratory tests have been widely accepted as an essential and integral part of good laboratory practice. As these programmes involve a great deal of repetitive statistical calculations and graphic presentation of data on quality control materials, many laboratories and practically all organisers of inter-laboratory quality assessment schemes increasingly rely on computers to handle the burdensome processing of data and to provide timely feedback in a manner that is easily understood and readily interpreted by analytical staff. However, in spite of the best effort to ensure reliable analytical performance, spurious and misleading results can still occur as a result of non-analytical errors which are not readily detected by methods designed to monitor the quality of analytical process. The use of sophisticated computer system has enabled our laboratory to check for the existence of some of these errors. This paper describes the application of computers in a variety of internal and external quality assessment programmes and demonstrates the usefulness of retrieving patients' cumulative test results and at the same time performing delta or percentage difference checks on such data in the detection of non-analytical errors and unexpected variations in results. The role of the computer in minimising transcription errors, reducing turn-around time of testing and reporting, as well as improving the quality of laboratory reports is also mentioned.

Clinical Laboratory Information Systems↗
PubMed1989

Clinical biochemistry in Singapore.

During the period from 1982 to mid-1989, there has been very significant changes and improvement in the practice and application of clinical biochemistry in Singapore. This paper highlights recent developments in the repertoire of biochemical analyses, utilisation of laboratory tests, biochemical screening in preventive health care, handling and delivery of patient specimens, advances in analytical techniques, automation, computerisation, quality assurance, training of laboratory personnel, and professional activities. It also draws attention to the restructuring of the Singapore General Hospital and the government Department of Pathology which frees these government institutions from the constraints of the civil service so that they would be sufficiently flexible to respond readily to the changing needs and expectations of the patients and users of laboratory services. This is the most prominent event and policy change in the history of health care services in Singapore that is expected to result in more cost-effective utilisation of resources and greater improvement in the quality of health care.

Automation↗
PubMed1988

The use of serum transferrin in the evaluation of protein-calorie malnutrition in cancer patients.

Forty-five patients with various malignancies of the gastrointestinal tract had their nutritional status assessed pre-operatively to determine the prevalence of malnutrition and to establish the correlation of malnutrition with post-operative outcome. Ten nutritional parameters were assessed. Based on these markers, we found a significant degree of malnutrition. Half of the study population developed some form of post-operative complication and nearly one quarter died. Of the ten nutritional markers studied, only serum transferrin had predictive value in determining post-operative outcome. The mean level of serum transferrin for patients with major complications was 162.0 mg/dl as compared with 221.2 mg/dl for those with none or minor complications. Patients with a serum transferrin level below the reference range of 200 mg/dl had most of the major life threatening complications and deaths. The other nutritional markers studied did not correlate well with post-operative outcome. We feel that serum transferrin is a useful nutritional marker to predict post-operative outcome and also to monitor the effect of nutritional support. However, based on a preliminary study, nutritional support may be required for periods longer than two weeks to show significant improvement in protein-calorie malnutrition. We will consider giving adequate support for a longer period on a further study using serum transferrin as a marker to determine its value in monitoring any reversal of malnutrition.

Female↗
PubMed1986

Computers in clinical laboratory management in Singapore.

In 1974, an off-line mini-computer system was introduced in the Clinical Biochemistry Laboratories of the Government Department of Pathology in Singapore. With the resiting of the 24-hour emergency biochemistry laboratory on the same floor as the Haematology Department within the new Singapore General Hospital, an on-line computer system was installed in 1983 to serve both the emergency biochemistry and haematology laboratories. An almost identical on-line system was also purchased in 1984 to replace the aged off-line system at the Department of Pathology. A description of the new computer systems based on Eclipse S/140 computers and Medical Information Technology (Meditech) software using Meditech Interpretive Information System (MIIS) language will be given. The specific features required and the selection criteria for the on-line systems are also discussed. The systems are used for the acquisition and processing of all patient and test data of the laboratories, direct capture of data from automated instruments, generation of work schedules and laboratory reports, compilation of work done, workload and revenue statistics and a variety of other reports. Patient cumulative records and quality control statistics are available on a real-time basis, thus greatly facilitating enquiries on patient results and monitoring of analytical performance. Prior experience with an off-line system and careful planning have been helpful in greatly shortening the preparatory period required for the smooth implementation of the on-line systems. Use of the systems has significantly improved laboratory management and has resulted in improved quality, and higher efficiency and productivity.

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↗