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B W Steele

Publications and source records attributed to B W Steele.

27 records · Page 2Linked to original sources
PubMed1978

An enzymatic triglyceride method that is suitable for long-term population studies.

An enzymatic triglyceride method has been shown to be a suitable alternative to the Lipid Research Clinics' extraction/fluorometry method in long-term population studies. Correlation of results obtained with this method by this laboratory (y-axis) and by the Minneapolis Lipid Research Clinic Laboratory (x-axis) during a nine-week standardization period produced a curve with an intercept of -72 mg/liter, a slope of 1.019, and a correlation coefficient of r=0.996 (n=47). During this standardization period certain methodological problems were observed and corrected. An increase in background in certain clinical specimens, caused by spontaneous degradation of NADH, was observed, accurately measured, and taken into account when appropriate.

Glycerol Kinase↗
PubMed1977

Evaluation of clinical chemistry laboratory performance in twenty Veterans Administration hospitals.

Twenty highly automated Veterans Administration (VA) Hospital laboratories participated in a study to evaluate their performances of routine chemistry tests. Ten of the laboratories had been identified as "superior" on the basis of previous College of American Pathologists Surveys. Several aspects of proficiency surveys were simultaneously examined: use of masked vs. unmasked survey specimens, methods of ranking, and comparison of medically useful performance criteria. The laboratories were found in general to be performing at the level of the state of the art and, more importantly, realistically meeting the criteria for medical needs for most routine tests. There was no difference between results obtained with masked and unmasked specimens. The ten "superior" laboratories showed slightly greater precision than the others, but were not more accurate, and two of them performed very poorly in the present study. The sum of squared SDI's was found to be a helpful technic for ranking and identifying outstanding and poor performances.

Blood Chemical Analysis↗
PubMed1977

Serial serum creatine phosphokinase MB isoenzyme activity after myocardial infarction. Studies in the baboon and man.

Serum CPK-MB iosenzyme activity was measured serially after mercury embolization of the left circumflex coronary artery in five baboons and after clinical acute myocardial infarction (AMI) in 20 patients. The calculated amount of enzyme released into the baboons' circulation (CPK-MBR) correlated well (r = 0.991) with the amount of MB isoenzyme depleted from the myocardium (CPK-MBD) when a previously determined decay constant (Kd) was used, but not when Kd was calculated from individual curves or when CPK-MM values were used. In clinical AMI, CPK-MMR averaged 97% (0 to 350%) greater than CPK-MBR, probably because of release of MM isoenzyme from nonmyocardial sources. The mean Kd for CPK-MB in patients (0.0012 min-1) was significantly (P less than 0.01) lower than that obtained in the baboon following bolus injections (0.0018 min-1), probably reflecting delayed myocardial release of enzyme. Therefore, in both experimental and clinical AMI, serial samples for CPK-MB activity, but not total or CPK-MM activity, could provide an accurate index of myocardial enzyme depletion.

Animals↗
PubMed1976

Enzymatic determinations of cholesterol in high-density-lipoprotein fractions prepared by a precipitation technique.

An enzymatic method for cholesterol in serum [Clin. Chem. 20, 470 (1974)] was initially found to be unsatisfactory for measuring cholesterol in high-density-lipoprotein fractions prepared by precipitation with Mn2+. A fine precipitate formed in the cuvette and cholesterol values were falsely increased. We describe a simple, convenient method for circumventing these problems. An ethylenediaminetetraacetate solution is used to reconstitute the enzymatic reagent. Cholesterol values by this procedure correlated with those obtained by the Lipid Research Clinic's procedure for the same lipoprotein fraction preparations (regression slope, .998; Y-intercept, 8.9 mg/liter; correlation coefficient, .984; standard error of the estimate, 16.8 mg/liter). Precision of the assay, including the precipitation step, was calculated. The SDwithin day was 9.7 mg/liter and SDoverall was 23.7 mg/liter. Results for total cholesterol with the modified reagent were linearly related to concentrations exceeding 4 g/liter, thereby permitting determination of high-density-lipoproteins and total cholesterol in a single run.

Chemical Precipitation↗
PubMed1975

Chemical inhibition method for alkaline phosphatase isoenzymes in human serum.

The authors adapted a chemical inhibition procedure using L-phenylalanine and urea as specific inhibitors to quantitate the activities of bone, liver, and intestinal alkaline phosphatase (ALP) isoenzymes in human serum. The results of this assay were compared with electrophoretic separation, gamma-glutamyl transpeptidase (GGTP) activity, and the clinical setting in a group of patients with elevated total ALP activity. In addition, expected ranges of serum ALP isoenzymes for healthy young men and also for a geriatric population are presented.

Adult↗
PubMed1975

An example of lyophilized protein-based materials not simulating patient sera.

Use of reconstituted lyophilized protein-based materials in the clinical laboratory is partly based on the assumption that these materials adequately simulate patients' sera. We examined several of these materials and found that certain ones do not have the same adsorbancies at 340 and 380 nm as do most sera. The implication of this is examined with respect to glucose determination by the hexokinase method on a dual-wave-length blank-subtraction instrument.

Autoanalysis↗