bluuebunny/crossref_metadata_2025_split huggingface dataset:
Measurement of urinary leukotrienes by reversed-phase liquid chromatography and radioimmunoassay.
Authors: Tagari P , Ethier D , Carry M , Korley V , Charleson S , Girard Y , Zamboni R 
Published: January 2020

Abstract
Leukotriene (LT) E4, an important LT metabolite appearing in urine, can be rapidly separated from normal and pathological urines by automated reversed-phase HPLC after a simple sample-processing. The recoveries of LTE4 afforded by this system (86.4 +/- 6.5%, mean +/- SEM for 60 ng/L, 85.4 +/- 0.3% for 200 ng/L) are superior to those obtained by a manual extraction method. Consistency of results is similar. Highly reproducible retention times combined with a radioimmunoassay allow one to identify (based on co-elution) and quantify as little as 8 ng/L LTE4 in a 10-mL urine sample. LTE4 concentrations in urine from healthy persons approach this value (17 +/- 5 ng/L), whereas samples from patients with cardiac ischemia show a wider range of concentrations (8 to 388 ng/L), up to 50 times the detection limit. Thus this method is applicable to the noninvasive investigation of leukotriene involvement in a wide range of ischemic, inflammatory, and hypersensitive conditions.
Diagnostic value of measuring pancreatic lipase and the P3 isoform of the pancreatic amylase isoenzyme in serum of hospitalized hyperamylasemic patients.
Authors: Panteghini M , Pagani F 
Published: January 2020

Abstract
We assayed amylase (AMY) isoenzymes by cellulose acetate electrophoresis and determined pancreatic lipase (LPS) activity by a turbidimetric colipase-supplemented method in 54 hospitalized hyperamylasemic patients (32 men and 22 women; mean age 61.5, SD 16, years). In AMY isoenzyme analysis, use of a value for P3 isoform greater than 14 U/L as a positive test for acute pancreatitis gave a diagnostic efficiency of 92.6%, a predictive value of a positive test result of 90.5%, and a predictive value of a negative test of 100%. Four of 12 patients with other, nonpancreatic abdominal diseases had false-positive test results. LPS activity (cutoff limit, 700 U/L) was as effective as P3 isoform in distinguishing patients with acute pancreatitis (sensitivity, 100%) from those without acute pancreatitis (specificity, 81.3%). Thus, P3 isoform and LPS appear to be interchangeable markers of pathological release of pancreatic enzymes into the bloodstream during acute pancreatitis. This finding decreases the need for the expensive radiological procedures currently required to confirm this diagnosis. In particular, negative results virtually exclude acute pancreatitis.
Correlation between heart disorders and concentrations of directly measured atrial natriuretic peptide in plasma.
Authors: Fridrich L , Szekeres T , Hartter E , Schweighofer F , Gassner A , Laczkovic A 
Published: January 2020

Abstract
We used new commercially available direct radioimmunoassay to measure human atrial natriuretic peptide (h-ANP) in plasma from 48 individuals who were being evaluated for left and right ventricular function. For 13 healthy individuals with normal ventricular function these concentrations ranged up to 54 ng/L. Measurements of h-ANP clearly differentiated between normal subjects, patients with coronary artery disease, and patients who had undergone orthotopic heart transplantation (ANOVA P less than 0.0001, significant differences between all groups)--all showing normal ventricular function at rest. There was a strong negative correlation (r = -0.64, P less than 0.001) between left ventricular ejection fraction and h-ANP concentrations in plasma of patients with proven coronary artery disease, patients with cardiomyopathy, and healthy individuals. Results by the present method and methods involving extraction of the sample correlated well. Evidently the direct assay of h-ANP in plasma yields information that could be used to help evaluate heart disorders and other pathophysiological conditions causing increased h-ANP concentrations in plasma.
Concordance of creatine kinase-MB activity and mass.
Authors: Eisenberg P R , Shaw D , Schaab C , Jaffe A S 
Published: January 2020

Abstract
The recent availability of monoclonal antibodies that are highly specific for creatine kinase (CK; EC 2.7.3.2) MB isoenzyme should allow for the development of rapid, sensitive, and specific assays of CK-MB mass and activity. However, the relationship between the mass concentration of CK-MB and its activity in plasma has previously been thought by some to be variable. To determine the extent to which discrepancies of potential clinical significance might arise between measurements of activity and mass in plasma, we compared CK-MB activity and concentration in 1298 samples obtained from 226 patients admitted to the cardiac-care unit. CK-MB activity concentration was determined with an immunoadsorption assay, and mass concentration was measured by an automated "sandwich" assay (Magic Lite; Ciba Corning Diagnostics). Both of these assays are based on specific monoclonal antibodies for CK-MB. Values obtained with these assays correlated well (r = 0.94). Normal and abnormal values with the two assays were concordant in 96% of the samples. In all but three instances, differences occurred late after myocardial infarction and were characterized by minimal increases as determined by one method vs values at the upper limit of normal as determined with the other. Thus, measurements of CK-MB mass and activity concentrations in plasma with assays based on these specific monoclonal antibodies are comparable for the detection or exclusion of acute myocardial infarction.
Screening for microalbuminuria by use of a rapid, low-cost colorimetric assay.
Authors: Phillipou G , James S K , Seaborn C J , Phillips P J 
Published: January 2020

Abstract
We evaluated the pyrogallol red-molybdate(IV) method for quantification of urinary protein as a screening procedure for microalbuminuria by determining the assay's sensitivity and specificity at different concentrations of urinary albumin as measured by a comparison laser-nephelometric immunoassay. The pyrogallol red-molybdate(IV) method has sensitivity and specificity similar to that for other semiquantitative assays, but it is less expensive and sample throughput can be high if microtiter plate techniques are used.
Rheumatoid factors determined by fluorescence immunoassay: comparison with qualitative and quantitative methods.
Authors: Carpenter A B , Bartkowiak C D 
Published: January 2020

Abstract
Fluorescence immunoassay (FIA), a relatively new technique for measuring rheumatoid factors (RF), is automated, quantitative, and calibrated against the Centers for Disease Control reference material for RF. We studied the FIA method in relation to a panel of RF methods, both qualitative [latex (LA) and sheep cell agglutination (SSCA)], and quantitative [nephelometry and enzyme-linked immunoassay (ELISA)]. Regression analysis revealed a highly significant correlation between FIA and either LA (r = 0.90) or nephelometry (r = 0.87). The correlation between FIA and either SSCA (r = 0.62) or ELISA (r = 0.67) was less strong. FIA had the highest sensitivity (91%) of all these methods; the specificity was 86%. FIA provides an accurate, sensitive, and specific measure of RF, and is a good alternative for laboratories wanting to replace titer methods with automated laboratory analysis.
Erythrocyte sedimentation rate and C-reactive protein compared in the elderly.
Authors: Katz P R , Gutman S I , Richman G , Karuza J , Bartholomew W R , Baum J 
Published: January 2020

Abstract
The erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) concentrations were studied in 101 elderly individuals (mean age 72 y) to determine their utility as diagnostic aids in subjects with underlying infection/inflammation. Whereas ESR and CRP were both significantly increased in patients with infection or inflammation, or both, analysis of variance indicated that those subjects still alive six months later had significantly lower ESR values. Analysis of sensitivity, specificity, and positive predictive values indicated that neither test satisfactorily discriminated between patients with and those without ongoing active or chronic disease. Receiver-operating characteristic curve analysis confirmed the low true-positive/false-positive ratios of both ESR and CRP. In the elderly, neither CRP nor ESR has distinct advantages over the other, and both tests evidently have limited utility.
Interference of coumarin therapy with the "Heptest" owing to declining prothrombin concentrations.
Authors: Fischer J , Verbruggen B , Wessels H , Haanen C 
Published: January 2020

Abstract
The Heptest kit (Haemachem, Inc., St. Louis, MO) for quantifying heparin in plasma is based on heparin-mediated inhibition of factor Xa, resulting in prolongation of clotting time. In 19 of 55 plasma samples obtained from 32 patients concurrently receiving coumarin and heparin, Heptest results exceeded true heparin values by more than 0.2 int. unit/mL; four samples showed a deviation exceeding 0.4 int. unit/mL. We show here that these deviations are caused by coumarin-induced decreases of plasma prothrombin. This problem can be circumvented by adding purified prothrombin or normal plasma to the assay mixture.
Characterization of amniotic fluid lamellar bodies by resistive-pulse counting: relationship to measures of fetal lung maturity.
Authors: Dubin S B 
Published: January 2020

Abstract
Resistive-pulse counting studies of amniotic fluid lamellar bodies are presented and demonstrate a strong concordance with the predictions of accepted measures of fetal lung maturity. Uncentrifuged as well as centrifuged specimens could be evaluated, because cells and debris are rejected electronically. The technique is not affected by bilirubin or debris of lysed whole blood, and only mildly by meconium. Lamellar body number density and mean lamellar body volume were determined for 161 uncentrifuged and 241 centrifuged specimens. Number density maturity criteria (40,000/microL and 26,000/microL, respectively) were shown to be highly concordant with established measures of fetal lung maturity; mean lamellar body volume did not extend this concordance. Since electronic cell counters are generally available 24 h per day and the approach requires neither centrifugation nor subjective interpretation and is rapid and inexpensive, it is proposed that determining lamellar body number density by resistive-pulse counting may be a useful initial screen for the assessment of fetal lung maturity.
Interference of common household chemicals in immunoassay methods for drugs of abuse.
Authors: Warner A 
Published: January 2020

Abstract
I report how some adulterants affect results for drugs of abuse in urine as measured by Roche RIA, Syva emit d.a.u., and Abbott TDx fpia (fluorescence polarization immunoassay) for the following drugs: amphetamines, barbiturates, benzodiazepines, cannabinoids, cocaine, opiates, and phencyclidine (PCP). Sodium chloride interfered negatively with all of these drugs when assayed by emit and caused a slight decrease in measured benzodiazepine concentration by fpia. Drug concentrations were also decreased by added H2O2 (emit: benzodiazepine), Joy detergent (emit: cannabinoid, benzodiazepines, PCP), NaHCO3 (emit: opiate; fpia: PCP), or NaClO [corrected] (emit, RIA, fpia: amphetamines, opiates, PCP; emit, fpia: cannabinoid; emit: benzodiazepines). False-positive results were caused by H2O2 (fpia: benzodiazepines) and Joy (RIA, fpia: benzodiazepine, cannabinoid; fpia: barbiturate, amphetamine). Sodium bicarbonate causes a suspiciously high pH in the urine, NaClO [corrected] an apparently low pH (using pH paper).
Hypomagnesemia and low alkaline phosphatase activity in patients' serum after cardiac surgery.
Authors: Lum G , Marquardt C , Khuri S F 
Published: January 2020

Abstract
Significant decreases in magnesium (Mg) concentration and alkaline phosphatase (ALP, EC 3.1.3.1) activity in serum were seen in patients after cardiac surgery with cardiopulmonary bypass (Group 1), as compared with non-cardiac-surgery patients after general anesthesia (Group 2) or only spinal anesthesia (Group 3). Mean changes for Mg and ALP by the first postoperative day, compared with pre-operative baseline values, were as follows: Group 1: Mg -7.5 mg/L (-38.3%), ALP -46U/L (-48.4%); Group 2: Mg -3.3 mg/L (-17.4%), ALP -17 U/L (-16.5%); and Group 3: Mg -1.9 mg/L (-10.0%), ALP -15 U/L (-14.0%). The decreases in Mg and ALP observed in post-cardiac-surgery patients appear to be a consequence of the cardiac surgery and the cardiopulmonary bypass pump. Measurement of Mg and ALP in a subgroup of 10 cardiac-surgery patients for 10 days postoperatively showed initial decreases, with gradual recovery to near-normal values by the 10th day. That the changes in Mg and ALP seen postoperatively were not attributable to hemodilution alone was confirmed by measuring total-protein concentrations before and after operation. ALP requires Mg ion in vitro for optimal activity, but addition of Mg in the appropriate amounts to sera with low ALP activity did not restore ALP activity. The low ALP activity seen in post-cardiac surgery patients in vivo may perhaps be related to factors other than Mg that were removed by the cardiopulmonary bypass pump.
Proton nuclear magnetic resonance studies of plasma to determine metabolic status of patients with adult respiratory distress syndrome.
Authors: Kuo C D , Wu W G , Wang J H , Chen S M , Chiang B N 
Published: January 2020

Abstract
Adult respiratory distress syndrome (ARDS) is a non-cardiogenic pulmonary edema of various etiologies. Here we report the first application of proton nuclear magnetic resonance (NMR) for the detection of abnormal metabolites in plasma from patients with ARDS. By comparing plasma obtained from the systemic artery with that obtained from the pulmonary artery, we could study the metabolic status of the lung in patients with ARDS. Although their concentrations may vary, the peaks for acetate, acetoacetate, beta-hydroxybutyrate, phenylalanine, and other unidentified compounds in water-suppressed NMR of these patients' plasma were higher than in the normal controls. The proton NMR resonance at a chemical shift of about 7.4 ppm (relative to sodium tetradeutero-3-trimethyl-silylpropionate), presumably caused by phenylalanine and its related metabolites produced by a disordered amino acid metabolism, is detected in greater than 65% of the samples from ARDS patients. We discuss the detection of abnormal metabolites in terms of possible deranged metabolism of carbohydrates, lipids, or amino acids in this syndrome.
Interferographs. Users' Guide to Interferences in Clinical Chemistry Instruments. M. R. Glick and K. W. Ryder. Indianapolis: Science Publishers, Inc., 1987, viii + 190 pp, paperback, $20.00. ISBN 0-930116-07-0
Authors: Young Donald S 
Published: January 2020

Abstract
p 800: In the first column, the correct name (and the address) of the publisher is Science Enterprises, Inc., Box 88443, Indianapolis, IN 46208.
p 1018: Richard Patrick should be added to the list of authors.
p 1110: Corrections to this paper are detailed in a Letter by Hammer, Vol. 35, p 193.
p 1800: Column two, line nine: "12.5" should read "125."
p 1801: Column one, "Linearity" paragraph: "HDL-C" should read "HDL-FC" in lines nine and 14.
p 1803: Column two, last sentence in first full paragraph should read "...automated method, the interferences with the manual method were less."
p 2017: In the legend to Figure 1, the equation for G7 should read: y = -4012 x + 18. In Figure 2, there should be three dots above the 7 glucosyl units coordinate, the third being between the curve and the point just above the curve.
p 2045: In Figure 1 (right), read "41" instead of "91" in the integration values for the 2-3a fraction assay.
p 2141: Right-hand column, line 16: the formula for CNP-NAG should contain two N atoms.
Vol. 35:
p. 17: In the last part of the equation, "0.0835" should read "0.00835", and "0.0759" should read "0.00759."
p 517: See correction note in "The Clinical Chemist."
A regulatory model for clinical laboratories: an empirical evaluation.
Authors: Peddecord K M 
Published: January 2020

Abstract
Clinical laboratories in the United States are subject to various regulatory and accreditation programs, which mandate a broad range of requirements regarding personnel, quality-control systems, and analytical proficiency standards. Reported here, for a cross-section of U.S. laboratories, is the degree of compliance with these regulatory requirements, some other laboratory characteristics, and their relation to analytical proficiency. The results suggest that those laboratory characteristics that predict highest proficiency-test performance differ for each laboratory specialty. Regression models are presented that explain from 12% to 35% of the variation in analytical performance and suggest that factors outside of those specified in the regulatory model and other characteristics measured in this research are important. Indeed, the current regulatory approach may not ensure highest performance. Also discussed are the current status, limitations, and prospects for change of the clinical laboratory regulatory system.
Defective epithelial ion transport in cystic fibrosis.
Authors: Quinton P M 
Published: January 2020

Abstract
In America, cystic fibrosis (CF) is the most common fatal inherited disease. In the past few years new concepts have evolved regarding the etiology of CF, changing from an almost universal acceptance of the abnormality as a disease of abnormal mucus production to that of a disease of abnormal fluid and electrolyte transport. Although mucus production is increased, this probably occurs as a secondary defense or protection against more primary disturbances in electrolyte transport brought on by a defect in Cl- permeability that affects both fluid absorption and fluid secretion. Here I review the progress that has been made and some of the puzzles uncovered in recent investigations of electrolyte transport in secretory and absorptive processes in cystic fibrosis.
Antiarrhythmic drugs and the cardiac sodium channel: current models.
Authors: Sheldon R S , Hill R J , Duff H J 
Published: January 2020

Abstract
The major electrophysiological effect of Class I antiarrhythmic drugs is blockade of the cardiac sodium channel, thereby reducing the initial depolarization of the action potential and slowing impulse propagation. Despite the widespread use of these drugs our understanding of their mechanism of action is incomplete. Models based on electrophysiological studies predict that a receptor for Class I drugs is associated with the sodium channel, and that occupancy of this receptor causes blockade of the sodium channel. Recent radioligand studies with [3H]batrachotoxinin-A benzoate have identified a binding site for Class I drugs associated with rat cardiac myocyte sodium channels, which may be the predicted receptor. Binding of drugs to this site is saturable, reversible, stereospecific, and occurs at pharmacologically relevant concentrations with similar rank order of potency in vivo and in vitro. Drugs appear to bind preferentially to a closed state of the channel, thereby preventing channel opening and subsequent sodium influx.
Current concepts in proteinuria.
Authors: Waller K V , Ward K M , Mahan J D , Wismatt D K 
Published: January 2020

Abstract
Proteinuria, long recognized as a sign of renal disease, is a common laboratory abnormality in children and adults. Proteinuria may be transient or persistent; when persistent, the cause must be determined. Proteinuria may be primarily glomerular or tubular in origin. Glomerular proteinuria is usually an important concern. Tubular proteinuria often indicates the presence of tubulointerstitial or obstructive renal disease. Screening tests are available to detect albumin (the major protein in glomerular proteinuria), but there are no simple tests for immunoglobulin light chains and low-molecular-mass proteins, which predominate in overflow proteinuria and tubular proteinuria. These small proteins can only be detected by more sophisticated assays such as electrophoresis, isoelectric focusing, and chromatography. The association of glomerular and tubular types of proteinuria with specific disorders is reviewed in this paper, and current concepts in laboratory methodology for the study of proteinuria are summarized.
Simultaneous measurement of total and IgA-conjugated alpha 1-microglobulin by a combined immunoenzyme/immunoradiometric assay technique.
Authors: DeMars D D , Katzmann J A , Kimlinger T K , Calore J D , Tracy R P 
Published: January 2020

Abstract
alpha 1-Microglobulin (alpha 1m), a glycoprotein (Mr = 30,000) found in serum and urine, is also present in serum conjugated to monomeric IgA (alpha 1-m-IgA). We have developed a simultaneous enzyme-linked immunoenzyme/immunoradiometric assay that involves three different monoclonal antibodies. Assay of serial dilutions of serum and urine demonstrated parallelism. Normal mean concentrations in serum (n = 75) were: total alpha 1m, 2.33 mumol/L; alpha 1m-IgA, 1.24 mumol/L; unconjugated (free) alpha 1m, 1.09 mumol/L; molar ratio (alpha 1m-IgA/total alpha 1m), 0.53. The mean concentration of alpha 1m in eight urine specimens from normal individuals was 0.19 mumol/L, with no detectable alpha 1m-IgA. A low urinary pH does not significantly affect assay results, unlike assays of beta 2-microglobulin. In patients with myeloma-related renal disease, total and free alpha 1m values for serum correlated well with values for creatinine and beta 2-microglobulin in serum.
Composition of very-low-density lipoproteins in non-insulin-dependent diabetes mellitus.
Authors: Ishibashi S , Yamada N , Shimano H , Takaku F , Akanuma Y , Murase T 
Published: January 2020

Abstract
We studied the characteristics of very-low-density lipoproteins (VLDLs) composition in patients with non-insulin-dependent diabetes mellitus. VLDLs were isolated from 28 diabetics and 33 nondiabetics with a wide range of plasma lipid concentrations, so we could compare VLDL composition between the two groups at similar lipid concentrations. The mean cholesterol and triglyceride concentrations in plasma of diabetic subjects were 2170 (SD 570) and 2510 (SD 2230) mg/L, respectively, and 2230 (SD 560) and 2210 (SD 1830) mg/L in nondiabetics. Diabetic subjects showed positive correlations between plasma triglyceride concentrations and either preprandial blood glucose or glycated hemoglobin values (P less than 0.02 and less than 0.01, respectively). Concentrations of triglycerides, cholesterol, and apolipoproteins (apo) B, CII, CIII, and E in VLDL were not significantly different between diabetics and nondiabetics. At comparable triglyceride concentrations, the chemical compositions of the VLDL in the two groups were still very similar. Dividing the concentration of each component by the VLDL-apo B concentrations yielded similar contents of each component per unit of VLDL for the two groups. We conclude that the composition of VLDLs in diabetics is much the same as that in nondiabetics at comparable concentrations of triglycerides in plasma.