bluuebunny/crossref_metadata_2025_split huggingface dataset:
Prognostic Value of Rate of Decline of Creatinine Kinase and MB-Isoenzyme Activity after Acute Myocardial Infarction
Authors: Clark Gregory D , Haver Virginia M 
Published: January 2020

Abstract
The rate of decline of total creatine kinase (CK; EC 2.7.3.2) activity during the course of an acute myocardial infarction (AMI) was shown by Weinberger at al. (1) to be of prognostic value. In their study, patients in whom CK values declined by &lt;50% of their peak value within 48 h had an increased risk of re-infarction or dying. This prognosis was not related to sex, previous AMI, site of infarction, or coronary risk factors. We wanted to confirm these findings in our populations and determine if there was additional value/specificity in monitoring the rate of decline of the more heartspecific isoenzyme, CK-MB, within the first 24 h of patient treatment. Therefore, we examined the peak activity and rate of decline of total CK and of CK-MB in 35 patients diagnosed with an AMI.
Usefulness of Thromboxane B2 in Diagnosis of Renal Transplant Rejection
Authors: Gonzalez-Revalderia J , Sabater J , Villafruela J J , Ortuño J 
Published: January 2020

Abstract
Morelet et al. (1) assessed the usefulness of sequential urinary albumin measurements in 16 renal allograft recipients, eight with and eight without acute graft-rejection episodes. They concludedthat the urinary albumin/creatinine ratio is poorly specific in the diagnosis of acute renal rejection, as shown by a high proportion of false-positive results. In addition, they commented on similar findings-poor specificity and poor positive predictive value-for other urinary components, e.g., β2-microglobulin, neopterin, renal tubular enzymes, thromboxane B2 (TxB2), interleukin-2, and solubleIL-2 receptor.
The clinical chemist
Authors: David E. Bruns 
Published: January 2020

Abstract
I have pretty much made up my mind to run for President. What the country wants is a candidate who cannot be injured by investigation of his past history so that the enemies of the party will be unable to rake up anything against him that nobody ever heard of before. If you know the worst about a candidate to begin with, every attempt to spring things on him will be checkmated. Now I am going to enter the field with an open record. I am going to own up in advance to all the wickedness I have done, and if any Congressional committee is disposed to prowl around my biography in the hope of discovering any dark and deadly deed that I have secreted, why—let it prowl
Immunochemiluminometric and immunoradiometric determinations of intact and total immunoreactive parathyrin: performance in the differential diagnosis of hypercalcemia and hypoparathyroidism
Authors: Endres David B , Villanueva Rocheile , Sharp Charles F , Singer FrederIck R 
Published: January 2020

Abstract
Parathyrin (parathyroid hormone; PTH) was measured with three immunoassays: a two-site immunochemiluminometric (ICMA) and a two-site immunoradiometric (IRMA) method for intact PTH, and a sensitive radioimmunoassay for mid-region or "total" PTH, measuring both intact hormone and inactive fragments. Single specimens from normal subjects and from individuals with primary hyperparathyroidism, hypercalcemia associated with malignancy, and hypoparathyroidism were analyzed with all three methods. All individuals with primary hyperparathyroidism showed absolutely above-normal concentrations with the mid-region RIA, 28 of 29 did with the ICMA, and 21 of 29 did with the IRMA. PTH concentrations in primary hyperparathyroidism were most increased relative to normal subjects with the mid-region assay (10.4 times), less so with the intact assays (ICMA 5.5 times; IRMA 5.3 times). Concentrations of intact PTH were suppressed below normal in nearly all patients with hypercalcemia associated with malignancy, as measured with the ICMA (26 of 30) and the IRMA (28 of 30) assays. In marked contrast, results for mid-region PTH were normal or slightly above normal, consistent with studies suggesting that the parathyroids secrete both intact hormone and inactive fragments, the former being more sensitive to suppression by hypercalcemia. In hypoparathyroidism PTH concentrations were detectable but below normal in all patients by the intact assays and in all but one patient by the mid-region assay. These low concentrations are probably due to a nonspecific serum effect that could be resolved with selection of a more appropriate standard matrix. Although all three assays are useful in the differential diagnosis of hypercalcemia, two-site intact assays are more convenient and more specific in patients with compromised renal function.
Catecholamine sulfates as internal standards in HPLC determinations of sulfoconjugated catecholamines in plasma and urine
Authors: Strobel Gɒnther , Weicker HelmuT 
Published: January 2020

Abstract
A method is described to measure catecholamine sulfates from human plasma and urine by isocratic reversed-phase high-performance liquid chromatography with electrochemical detection. For this measurement we use catecholamine 3-sulfate isomers as internal standards and determine the sulfoconjugates only after eliminating the catecholamines. Catecholamines that have previously been used as internal standards are shown to cause a significant overestimation (P less than 0.05) of the catecholamine sulfates--by 10% to 25% and 20% to 42% in human plasma and urine, respectively. The detection limits (signal-to-noise ratio greater than 3) in plasma and urine samples were about 80 pmol/L for each analyte. The intra-assay and interassay CVs were less than 4.0% and 10.6% in human plasma and less than 6.6% and 12.8% in human urine, respectively. The calibration curves for all catecholamine sulfates in human plasma and urine were linear (r greater than 0.96; P less than 0.001) over the respective concentration ranges of 0.1-100 nmol/L and 5-1000 nmol/L.
Simple, optimized liquid-chromatographic method for measuring total hydroxyproline in urine evaluated
Authors: Reed P , Holbrook I B , Gardner M L G , McMurray J R 
Published: January 2020

Abstract
We have optimized a method for measuring total hydroxyproline (HYP) in urine by HPLC after release from urinary peptides by solid-phase hydrolysis on Dowex 50W x 8 ion-exchange resin. The HYP was derivatized with 4-chlor-7-nitrobenzo-2-oxa-1,3-diazole, and excess reagent was removed with the use of a 100-mg C18 Bond-Elut cartridge. The HYP derivative was separated isocratically at 30 degrees C on a 250 x 4.6 mm reversed-phase column containing 5-microns particles of Spherisorb S5 ODS-2, with S-carboxymethylcysteine as internal standard. Total assay time was 14 min. The standard curve for the method was linear from the detection limit for HYP, 3.6 mumol/L, to 10 mmol/L. The between-batch CV was less than 5.1% and the mean analytical recovery of HYP was 95% +/- 1.4%. Comparison with a commercially available colorimetric method showed good correlation: y = 1.158x + 19.76 mumol/L (Syx = 74, n = 120), but HPLC results were 15% higher, probably from incomplete hydrolysis with the colorimetric method. This method offers a considerable improvement in assay time, specificity, sensitivity, precision, and cost compared with the colorimetric method.
Further insights into the pathophysiology of hyperapobetalipoproteinemia: role of basic proteins I, II, III
Authors: Kwiterovich Peter O , Motevalli Mahnaz , Miller Michae , Bachorik Paul S , Kafonek Stephanie D , Chatterjee Subroto , Beaty Tern , Virgil Donna 
Published: January 2020

Abstract
Hyperapobetalipoproteinemia (hyperapoB), a familial lipoprotein disorder characterized by an increase in small, dense, low-density lipoprotein (LDL) particles, is strongly associated with coronary artery disease. There are two metabolic defects in hyperapoB: an increased synthesis of a very-low-density lipoprotein in liver, resulting in an overproduction of LDL, and a delayed clearance of post-prandial triglyceride and free fatty acids. To date, defects in the apolipoprotein B gene do not appear to explain the hyperapoB phenotype. Defect(s) in the uptake or intracellular metabolism of free fatty acids have been found in cells from hyperapoB patients. Three basic proteins (BPs)--BP I (Mr 14,000, pI 9.10), BP II (Mr 27,500, pI 8.48), and BP III (Mr 55,000, pI 8.73)--were isolated from normal human serum. Compared with normal fibroblasts, cultured hyperapoB fibroblasts incubated with BP I, which appears to be the same protein as acylation-stimulating protein (ASP), showed 50% less stimulation of triglyceride acylation and cholesterol esterification, whereas BP II markedly stimulated cholesteryl ester formation, and BP III caused no difference in response vs normal fibroblasts. However, in cultured normal human monocyte macrophages, BP III, but not BP I or BP II, stimulated cholesteryl esterification two- to threefold. BP I, BP II, and BP III may provide new insights into normal metabolism of lipids, lipoproteins, and free fatty acids and the pathophysiology of hyperapoB.
Relation between debrisoquine oxidation phenotype and morphological, biological, and pathological variables in a large population
Authors: Vincent-Viry M , Muller J , Fournier B , Galteau M M , Siest G 
Published: January 2020

Abstract
Factors affecting biological variations in debrisoquine-oxidation polymorphism were investigated in a population of 3065 unrelated supposedly healthy Caucasian subjects, ages 35 to 50 years. This population, including 1526 men and 1539 women, was used to determine whether the debrisoquine-oxidation phenotype can be related with environmental factors such as alcohol intake, smoking habits or medication; with morphological variables; or with 22 blood constituents and some pathological states. A single dose of 10 mg of debrisoquine sulfate was administered to determine the oxidation phenotype. A metabolic ratio (debrisoquine/4-hydroxydebrisoquine) of 10.0 defined a poor metabolizer [frequency of 8.2% (SD 1.0%)] in this sample. Dose recoveries of debrisoquine excretion (mean and SD) were 8.9% (11.9%) and 45.1% (32.2%) in extensive and poor metabolizers, respectively. The mean (SD) amount of debrisoquine administered that was excreted in urine as 4-hydroxydebrisoquine was 17.4% (17.3%) in extensive metabolizers and 0.5% (0.9%) in poor metabolizers. The main factors differing significantly between poor and extensive metabolizers were mean cell volume, mean corpuscular hemoglobin concentration, albumin, and ponderal index. No other blood constituents (e.g., cholesterol, glucose) differed between poor and extensive metabolizers. The lack of correlation with most of the variables tested is of interest in clinical trials, because our findings indicate that no subgroups will be required, making selection of subjects easier.
Analyzing quality-control trends with moving slope charts
Authors: Smith S Jay , Myers Gary L 
Published: January 2020

Abstract
We have developed and evaluated a new procedure for detecting trends in quality-control measurements and applied it to laboratory data. The method requires the use of sequential or "moving" slope estimates to identify trends. Formulae are derived to estimate the regression error for the moving slope directly from the standard deviation of the analytical measurements obtained during characterization runs. Control limits for the moving slope depend only on this regression error, the span of the slope, and the desired statistical level of control. The moving slope can be plotted with control limits to determine out-of-control points. The statistical power of the moving slope is found to be much greater than that of an often-used test for trends. An example of the use of the moving slope is shown for quality-control measurements for total cholesterol obtained over several years. We conclude that the moving slope procedure has considerably more statistical power than trend rules and that it yields more useful information to the analyst.
Lipase isoforms and amylase isoenzymes: assays and application in the diagnosis of acute pancreatitis
Authors: Lott John A , Lu Carrle J 
Published: January 2020

Abstract
Pancreatic juice and serum from patients with acute pancreatitis contain three enzymes that have lipolytic activity: L1 and L2, which are pancreatic isoenzymes or isoforms of lipase (EC 3.1.1.3), and L3, which is probably pancreatic carboxyl ester lipase, also known as cholesterol esterase (EC 3.1.1.13). These enzymes are readily separated electrophoretically on agarose and can be developed with an overlay of Kodak Ektachem lipase slide material. The latter acts as a dry-reagent developing substrate, with the enzymes producing blue bands in the slide material. We found L1 in about one-half of normal persons, L2 in none, and L3 in all. We assayed for amylase (EC 3.2.1.1), amylase isoenzymes, lipase, and lipase isoforms in the sera of 100 patients with suspected acute pancreatitis. L2 lipase has the greatest diagnostic efficiency for the diagnosis of pancreatitis, compared with total amylase, P3 amylase, and total lipase. Lipase and L2 could replace amylase, an inefficient test, for the diagnosis of patients with suspected acute pancreatitis. In patients receiving organ transplants, a serum amylase value of greater than 300 U/L or a lipase of greater than 1000 U/L discriminated well between patients with and without complications and (or) acute rejection.
Quantification of plasma lipoproteins by proton nuclear magnetic resonance spectroscopy
Authors: Otvos J D , Jeyarajah E J , Bennett D W 
Published: January 2020

Abstract
A new analytical procedure for quantifying plasma lipoproteins by proton nuclear magnetic resonance (NMR) spectroscopy has been developed that potentially offers significant advantages over existing clinical methods used for assessing risk of coronary heart disease. Analysis of a single spectrum of a nonfasting plasma sample, acquired simply and rapidly at moderate magnetic field strength (250 MHz), yields a complete profile of lipoprotein concentrations: chylomicrons and very-low-, low-, and high-density lipoproteins. The method is based on curve-fitting (spectral deconvolution) of the plasma methyl lipid resonance envelope, the amplitude and shape of which depend directly on the amplitudes of the superimposed methyl resonances of the lipoprotein components. A linear least-squares curve-fitting algorithm was developed to efficiently extract the signal amplitudes (concentrations) of the lipoproteins from the plasma spectrum. These signal amplitudes correlate well with lipoprotein concentrations determined by triglyceride and cholesterol measurements.
Elimination of undesired cross-reactants by using mixtures of antibodies: experimental and theoretical evaluations of hapten radioimmunoassays
Authors: Boutten B , Ezan E , Mamas S , Dray F 
Published: January 2020

Abstract
This study shows that the specificity of radioimmunoassays can be improved by including a second antibody raised against an undesired cross-reactant. In a radioimmunoassay of prostaglandin E2 (PGE2) involving a monoclonal antibody, the cross-reactivity with 6-keto-prostaglandin E1 (6kPGE1) was decreased from 20% to 2% by including a high concentration of a polyclonal anti-6kPGE1. A similar increase in specificity was obtained in the assay of a larger hapten, luliberin (luteinizing hormone releasing hormone); the cross-reactivity of a luliberin analog was decreased 20-fold. Equations derived from the Law of Mass Action were used for the mathematical analysis and for the computer simulation of changes in assay affinity and specificity according to the quantity and quality of the mixed antibodies. The model gave values that agreed well with experimental data; it promises to be quite useful in designing specific radioimmunoassays.
Automated determination of creatine kinase activity in serum with use of thermostable glucokinase
Authors: Maeda Ikuhiro , Hayashi Sadao , Amino Nobuyuk , Miyai Kiyosh 
Published: January 2020

Abstract
We measured creatine kinase (CK, EC 2.7.3.2) activity in serum with a new reagent system utilizing thermostable glucokinase (EC 2.7.1.2). Automated determinations were performed with Toshiba's Model TBA-80S Biochemical Analyzer. Precision studies demonstrated within-run and between-run CVs of 0.4%-2.4% and 2.8%-3.1%, respectively. The response linearity was confirmed for CK activity up to 1000 U/L at 37 degrees C. CK activities correlated well (r = 0.997) with those obtained by the manual method recommended by the German Society for Clinical Chemistry (measuring at 37 degrees C) involving hexokinase (EC 2.7.1.1). However, CK activities measured by our method were consistently higher than those of the hexokinase method at reaction temperatures of 30, 37, and 40 degrees C. These data indicate that the new method with thermostable glucokinase is better than that with thermo-unstable hexokinase for determination of CK activity in serum.
Concentration of Mn-superoxide dismutase in serum in acute myocardial infarction
Authors: Usui Akihlko , Kato Kanefusa , Tsuboi Hldeyuki , Sone Takahito , Sassa Hirom , Abe Toshio 
Published: January 2020

Abstract
Serum concentrations of manganese-containing superoxide dismutase (Mn-SOD; EC 1.15.1.1), a mitochondrial enzyme present in high concentrations in the heart, were measured successively by enzyme immunoassay in 18 patients with acute myocardial infarction (AMI) and in eight with angina pectoris. Results were compared with creatine kinase (EC 2.7.3.2) isoenzyme MB (CK-MB) concentrations in the same specimens. The mean (and SD) serum Mn-SOD concentration in 120 healthy adults was 77.5 (18) micrograms/L. Mn-SOD concentrations exceeding 150 micrograms/L (greater than mean + 4 SD) were considered above-normal. In patients with AMI, the Mn-SOD concentration was 80 (16.8) micrograms/L on admission and increased gradually after the first hospital day. The peak, 260 (109) microgram/L, occurred on the fourth hospital day, at which time the Mn-SOD concentrations in all AMI patients were above normal. Thereafter the Mn-SOD concentration decreased slowly, but still was above normal in 14 of 18 patients on the seventh hospital day. On the other hand, in patients with angina pectoris, the Mn-SOD concentration was 78 (11) micrograms/L on admission and did not increase significantly [peak value 97.5 (42) micrograms/L on the fourth hospital day]. The serum concentration of Mn-SOD is a potentially useful marker for estimating cardiac mitochondrial damage and for diagnosing AMI, especially in the late phase.
Assessment of split-sample proficiency testing for cholesterol by use of a computer simulation model
Authors: Bennett Sterling T , Connelly Donald P , Eckfeldt John H 
Published: January 2020

Abstract
We developed a computer model to study the use of patients' specimens to assess compliance of cholesterol measurement performance with the 1992 goals of the Laboratory Standardization Panel of the National Cholesterol Education Program. The model uses Monte Carlo techniques to simulate cholesterol measurements that are subject to both systematic and random error. Split-sample measurements by a clinical laboratory and by a reference laboratory are compared by using linear regression to estimate clinical laboratory bias and imprecision; subsequently, according to specified decision limits, the performance of the clinical laboratory is classified as acceptable or deficient. We have quantified the influence of the bias and imprecision of the clinical laboratory, the imprecision of the reference laboratory, the number of split samples compared, and the decision limits on the accuracy of the classification of clinical laboratory performance. Unless the decision limits are carefully selected and a sufficient number of split samples are used, clinical laboratory performance will be frequently misclassified.
Improved sample preparation for accurate determination of low concentrations of lead in whole blood by graphite furnace analysis
Authors: Jacobson Beryl E , Lockitch Gillian , Quigley Gayle 
Published: January 2020

Abstract
The effect of low concentrations of lead on pre- and post-natal growth and development is a current concern. We describe a simple method of sample preparation for direct determination of lead in whole blood by Zeeman graphite-furnace atomic absorption spectrometry. This procedure improves analytical precision and accuracy of lead determinations at low concentrations as compared with published furnace data. At blood lead concentrations of 0.25, 1.98, and 3.76 mumol/L, within-run CVs were 3.2%, 1.8%, and 1.4% respectively; between-run CVs were 7.3%, 2.9%, and 2.2%. Accuracy, as demonstrated by analytical recovery, ranged from 99% to 102%. Our reproducibility/accuracy score in the 1989 Quebec interlaboratory comparison program was 96% compared with the target, second best of 66 participating laboratories.
Laboratory process specifications for assuring quality in the U.S. National Cholesterol Education Program
Authors: Westgard J O , Petersen P H , Wiebe D A 
Published: January 2020

Abstract
We have assessed the laboratory specifications necessary for ensuring that cholesterol testing processes satisfy the quality required by the U.S. National Cholesterol Education Program (NCEP). A model for setting process specifications has been developed to relate the NCEP guidelines for medical interpretation of a cholesterol test to the pre-analytical and analytical variables that can affect a test result. Using this model, we derived specifications for the imprecision (coefficient of variation, CV, or standard deviation, s) and inaccuracy (bias) that are allowable under stable operation, as well as the quality-control procedures (control rules and number of control measurements) that are necessary to detect unstable operation. The NCEP goals of an allowable CV less than or equal to 3% and an allowable bias no greater than +/- 3% are inadequate for assuring the quality of an individual or single cholesterol test when monitoring performance with many of the statistical quality-control procedures currently used in the U.S. With quality-control procedures having two control measurements per run, a CV of 3% is allowable only when bias is zero; a CV less than or equal to 2% is necessary if bias is +/- 3%. With quality-control procedures having four control measurements per run, a CV of 3% is allowable when bias is +/- 1.5%; a CV less than or equal to 2.5% is required if bias is as large as +/- 3%. For two serial tests, the NCEP 3% goals are adequate for current quality-control procedures having four control measurements per run.
Different constructs for the expression of mammalian gamma-glutamyltransferase cDNAs in Escherichia coli and in Saccharomyces cerevisiae
Authors: Angele C , Oster T , Visvikis A , Michels J M , Wellman M , Siest G 
Published: January 2020

Abstract
To prepare a reference material for gamma-glutamyltransferase (GGT; EC 2.3.2.2) measurements in clinical chemistry, we constructed different vectors containing either the rat kidney or the human hepatoma Hep G2 GGT cDNA downstream from an inducible promoter for expression in Escherichia coli and Saccharomyces cerevisiae. Transformed bacterial and yeast cells were tested for GGT production by use of Western blot analysis and enzymatic activity measurements. Both rat renal and Hep G2 GGT cDNAs were expressed in E. coli, producing active and nonglycosylated enzymes localized in the periplasmic space. Recombinant Hep G2 GGT was synthesized as a single-chain protein, unlike rat renal GGT, which presented two polypeptides of 62 and 30 kDa, identified as the precursor and a GGT heavy-subunit-like peptide, respectively. Rat renal GGT was produced in S. cerevisiae as two polypeptides, 55 and 30 kDa, detected by antisera against rat renal GGT. These results suggest maturation mechanisms such as glycosylation and cleavage steps, enhancing the interest of S. cerevisiae as a useful expression system for producing active mammalian proteins as reference materials.