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S Y Chu

Publications and source records attributed to S Y Chu.

At least 109 records · Page 6Linked to original sources
PubMed1984

Assessment of a solid-phase reagent for urinary specific gravity determination.

We have compared the specific gravity (S.G.) determined by the N-Multistix method with that obtained from the Total Solids (TS) meter. Overall, 88.7% of the specific gravity results obtained with the reagent strip method were within 0.005 of those obtained with the TS meter. There was a good correlation between the methods and there was no bias for the group means obtained by either method. A good correlation was also found between the S.G. on the strip and osmolality (correlation coefficient of 0.955). The results obtained with the reagent strip for urinary specific gravity therefore appear acceptable for routine laboratory purposes.

Freezing↗
PubMed1984

A comparison of frequency and quantitative dietary methods for epidemiologic studies of diet and disease.

Agreement between frequency and quantitative dietary methods was assessed for the ability of frequency intake data to substitute for quantitative intake data in diet-disease investigations. Frequency and quantitative intakes of 342 male subjects participating in an ongoing case-control study in Hawaii during 1981-1982 were obtained using a recall interview method designed to assess usual dietary habits. The extent of agreement between frequency and quantitative intakes of various dietary components (44 food items, 20 food groups, 8 nutrients) was determined at the group and individual subject levels, and with regard to specific study objectives. The results showed that for studies based on aggregate data, frequency and quantitative dietary methods will give reasonably comparable results in analyses involving food items. However, for similar studies involving food groups and nutrients, and for all studies based on individual data, frequency dietary methods cannot be relied on to yield the same diet-disease associations as would corresponding quantitative methods.

Diet↗
PubMed1983

Differences in reaction characteristics between human and bovine-based control materials for iron determination.

Reaction rate studies were carried out on various quality control specimens using a ferrozine iron determination kit. The time required for complete color formation differed among the various materials tested. Quality control materials of bovine origin required a much longer incubation time for full color formation. Using a fixed incubation procedure, the bovine controls would give a falsely low result. The present study suggests that caution is indicated when quality control data using bovine materials are interpreted.

Animals↗
PubMed1982

A "one-minute" direct bilirubin determination using the Abbott ABA-100 Bichromatic Analyser.

We describe a "one-minute" direct bilirubin procedure using the ABA-100. The procedure correlates well with the manual Jendrassik-Grof method and gives good precision at a relatively low direct bilirubin level. In comparison with certain other Abbott ABA-100 direct bilirubin methods, the proposed procedure appears to be the least affected by the presence of high unconjugated bilirubin levels.

Autoanalysis↗
PubMed1981

Radioimmunoassay of carteolol in human plasma.

A radioimmunoassay for the direct measurement of carteolol, a new beta-adrenoreceptor blocker, in human plasma was developed. Carteolol was acylated to form O-glutarylcarteolol, which was conjugated to bovine serum albumin to provide the immunogen. Antibody to carteolol was raised in New Zealand albino rabbits. The tracer was the radioiodinated derivative of O-glutarylcarteolol-tyrosine methyl ester conjugate. The method is highly sensitive, with a lower quantifiable concentration of approximately 0.4 ng of carteolol/ml using 0.1 ml of plasma, and has good specificity, with the major metabolite (8-hydroxycarteolol) showing only 0.2% cross-reactivity. It is reproducible, with relative standard deviations from triplicate standard curves being mostly within +/- 8%. The method is currently being used to monitor carteolol levels in clinical samples.

Animals↗
PubMed1981

Nutrient intakes in relation to cancer incidence in Hawaii.

A representative sample of 4657 adults greater than or equal to 45 years of age from the 5 main ethnic groups in Hawaii (Caucasians, Japanese, Chinese, Filipinos and Hawaiians) were interviewed during 1977-1979 regarding their diets. Quantitative food-consumption histories were obtained, from which average daily intakes of fat (saturated, unsaturated, cholesterol, meat, dairy, fish, animal, vegetable and total), protein (animal, meat, fish, dairy and total), carbohydrate, and vitamins A and C (including supplements) were calculated using food-consumption data from standard sources. Multiple regression analysis, with sex as a controlled variable, was used to assess the statistical relationship between these ethnic-sex-specific intakes and corresponding population-based cancer incidence rates of 15 selected sites for which nutrient components are suspected to be either causal or protective. Based on pre-set criteria for establishing important relationships, significant positive associations were found for 6 of the cancer sites: breast cancer with fat (saturated, unsaturated, animal, total) and protein (animal), corpus-uteri cancer with the same components as breast cancer, prostate cancer with fat (saturated, animal) and protein (animal, total), stomach cancer with fat (fish only) and protein (fish only), lung cancer with cholesterol, and laryngeal cancer with cholesterol. Breast and corpus-uteri cancers also showed significant negative associations with carbohydrate intake. The implications of these findings for future research are discussed.

Aged↗
PubMed1981

Dietary fat intake and cancer incidence among five ethnic groups in Hawaii.

Average daily intakes of several components of fat in the diets of the five main ethnic groups in Hawaii were determined from personal interviews of 4137 subjects regarding their food consumption in a usual week. In general, fat intake was highest among Caucasians and lowest among Filipinos. Cholesterol intake did not follow the same pattern as that of the other fat components. The intake of total fat showed good correlation with the ethnic-specific incidence rates of breast cancer in Hawaii but not with colon or prostate cancer rates. There was no correlation of cholesterol intake with colon cancer incidence.

Aged↗
PubMed1978

High-pressure liquid chromatographic determination of 8-hydroxycarteolol in plasma and urine using electrochemical detection.

Assay of 8-hydroxycarteolol (a metabolite of carteolol) was achieved using high-pressure liquid chromatography with electrochemical detection. Plasma or urine samples alkalinized by addition of a sodium carbonate solution were extracted with ethyl acetate or chloroform. The residues from evaporation of the organic extracts were redissolved in pH 2.1 phosphate buffer, and the solutions were chromatographed on a Partisil 10 SCX chromatographic column. The detection of 8-hydroxycarteolol was accomplished using an electrochemical detector. The procedure is rapid, specific, and highly sensitive. Reproducible results can be obtained, with relative standard deviations from analysis of replicate samples within +/- 8%. With 1-ml samples, the lower quantifiable concentrations of 8-hydroxycarteolol in plasma and urine are approximately 5 and 25 ng/ml, respectively.

Animals↗
PubMed1978

Influence of pH on the simple solubility test for myoglobinuria.

We have investigated the effect of urine pH on the simple solubility test for myoglobinuria and found that the sensitivity of the test is very pH dependent. As much as a 10 fold increase in sensitivity can be obtained if the test is performed at pH 7.5 instead of pH 5.5. As such, we recommend that the urine pH should first be adjusted within the range 7.5--8.0 before performing the solubility test for myoglobinuria.

Humans↗
PubMed1978

Sample application position and the resolution of protein separation on the Beckman Microzone Electrophoretic System.

Many clinical laboratories use the Beckman Microzone electrophoretic system (Beckman Instruments Inc. Fullerton, CA 92634) for serum protein separation. Although detailed instruction is supplied in the manufacturer's manual (1) for protein separation, the effect of different sample application positions on the cellulose acetate membrane is not discussed. We have processed the serum specimen in various application positions and found that there is a definite relationship between the resolution of fractionated protein bands and the application position, particularly with specimens from patients with monoclonal gammonpathies. The resolution of the protein bands increases as the sample is applied closer to the anode end of the cellulose acetate strip. Although studies were carried out on the Beckman electrophoretic system, a similar application effect may be anticipated with other electrophoretic systems.

Blood Protein Electrophoresis↗
PubMed1978

Reaction rate studies of two enzymatic cholesterol reagent kits.

Reaction rate studies were carried out on various specimens using two commercial enzymatic cholesterol determination reagent kits (BMC and Worthington). The time required for complete colour formation differed between the two reagent systems and each kit required different incubation times for the standards and specimens to come to color completion. The choice of standards was found to be very important when using these enzymatic kits.

Cholesterol↗
PubMed1977

Gas chromatographic determination of pemoline in biological fluids using electron capture detection.

A simple and sensitive gas chromatographic (GC) method for the determination of pemoline in biological fluids, utilizing electron capture detection is described. Plasma samples with a pemoline analog added as internal standard were deproteinized with sulfosalicylic acid, and the supernatants were heated at 80 degrees. The pemoline-dione formed was extracted with benzene, and the extract was analyzed on a gas chromatograph equipped with a tritium foil electron capture detector. Poly A-103 (3%) on Gas-Chrom Q (100-120 mesh) packed in a 3-ft. silanized glass column was used as the stationary phase, with nitrogen serving as carrier gass. Under the same GC conditions, benzene extracts of pemoline-dione from acid-hydrolyzed urine samples were analyzed. Us-ng 1 ml of plasma or urine, the lower limit for the assay was about 0.1 microgram/ml. The method is accurate and reproducible, with a relative standard deviation with +/-4%. Mandelic acid (a metabolite of pemoline) does not interfere with the assay.

Animals↗
PubMed1976

High-pressure liquid chromatographic determination of 2-aminoethyl hydrogen sulfate in plasma and urine.

A sensitive and specific method for the analysis of 2-aminoethyl hydrogen sulfate in biological fluids by high-pressure liquid chromatography is described. Aliquots from deproteinized plasma or from acidified urine were subjected to ion-exchange clean-up by eluting with water through two columns packed with Dowex 1-X4 (Cl- form) and Dowex 50W-X8 (H+ form) resins. Recoveries in the eluates were consistent and quantitative (95-100%). Effluents from such treatment were chromatographed on a Durrum cation-exchange column with 0.05 M citrate buffer containing 0.15 N Na+ (pH 2.6). Detection was accomplished with an automated fluorescamine detection system. Using 2 ml of plasma or urine, 2-aminoethyl hydrogen sulfate could be assayed at concentrations of 0.3 mug/ml. Linear responses were observed up to at least 133 mug/ml. The method is both accurate and reproducible with a relative standard deviation of about +/- 4.0%.

Animals↗