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Biomedical subjects

K S Chua

Publications and source records attributed to K S Chua.

23 records · Page 2Linked to original sources
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↗
PubMed1977

Urinary steroid excretion by the squirrel monkey (Saimuri sciureus).

Urinary steroids and steroid conjugates were measured in the squirrel monkey (Saimuri sciureus). The principal steroids excreted were cortisol, 11beta,17alpha,20beta,21-tetrahydroxy-4-pregnen-3-one (20beta-dihydrocortisol), alpha- and beta-cortol and alpha- and beta-cortolone. The majority of the steroids were excreted unconjugated and a conspicuous feature of the pattern was the large amount of urinary free cortisol. Unlike man there was an insignificant excretion of 3alpha,17alpha,21-trihydroxy-5beta-pregnane-11,20-dione (tetrahydrocortisone) and 3alpha,11beta,17alpha,21-tetrahydroxy-5beta-pregnan-20-one (tetrahydrocortisol). A steroid not previously identified in urine from any species was one of the major glucuronide conjugates; it was characterized as having the structure 3beta,17alpha,20xi,21-tetrahydroxy-5beta-pregnan-11-one. Administration of dexamethosone resulted in complete suppression of steroid output, whilst the response to adrenocorticotrophic hormone was inconstant.

Adrenocorticotropic Hormone↗
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↗