bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modified method for determining carcinoembryonic antigen in the presence of human anti-murine antibodies
Authors: Morrissey N E , Quadri S F , Kinders R , Brigham C , Rose S , Blend M J 
Published: January 2020

Abstract
The increasing use of monoclonal antibodies (MAbs) for disease diagnosis and therapy has created a class of patients at risk for systematic error in clinical testing due to interference by human anti-murine antibodies (HAMA). HAMA interference is often difficult to detect and can cause either an increase or a decrease in apparent concentrations of antigen present. We undertook a clinical study to test a HAMA-resistant enzyme immunoassay (EIA) format for carcinoembryonic antigen (CEA) determination. Using the Food and Drug Administration-approved CEA-EIA Monoclonal One-Step Assay (Abbott) with the addition of an acid/heat extraction of patients' specimens, we found that the resulting CEA values accurately reflected the patients' status. We demonstrated that the acid/heat-extracted specimens yield linear dilution curves and show analytical recoveries of added CEA in the range of 76-123% in HAMA-positive specimens and 86-103% in HAMA-negative specimens. The correlation of CEA values in extracted vs unextracted specimens from 184 patients and control subjects was 0.9963. The CEA detection limit of the assay was 1.6 micrograms/L for the extracted samples.
Ion-chromatographic determination of plasma oxalate reexamined
Authors: Petrarulo M , Cerelli E , Marangella M , Maglienti F , Linari F 
Published: January 2020

Abstract
This new procedure for determining oxalic acid in plasma is based on sample deproteinization with hydrochloric acid and acetonitrile and subsequent ion-chromatographic assay of the neutralized supernate. Sample pretreatment produces very clean samples, which ensures long column life. Mean analytical recovery of oxalate (5.0-10.0 mumol/L) added to plasma samples averaged 98.6 +/- 6.2%; imprecision (CV) was 5.2% (at 2.2 mumol/L) and the detection limit was 0.5 mumol/L at a signal-to-noise ratio of 5:1. Ascorbate to oxalate conversion was &lt; 0.2%, indicating that the procedure is free from ascorbate interference. Plasma oxalate concentrations, measured in samples from 31 healthy persons, ranged from 0.8 to 3.4 mumol/L (mean 1.89, SD 0.75 mumol/L), which agrees with results from indirect radioisotopic dilution methods.
Receiver-operating characteristic (ROC) plots: a fundamental evaluation tool in clinical medicine
Authors: Zweig M H , Campbell G 
Published: January 2020

Abstract
The clinical performance of a laboratory test can be described in terms of diagnostic accuracy, or the ability to correctly classify subjects into clinically relevant subgroups. Diagnostic accuracy refers to the quality of the information provided by the classification device and should be distinguished from the usefulness, or actual practical value, of the information. Receiver-operating characteristic (ROC) plots provide a pure index of accuracy by demonstrating the limits of a test's ability to discriminate between alternative states of health over the complete spectrum of operating conditions. Furthermore, ROC plots occupy a central or unifying position in the process of assessing and using diagnostic tools. Once the plot is generated, a user can readily go on to many other activities such as performing quantitative ROC analysis and comparisons of tests, using likelihood ratio to revise the probability of disease in individual subjects, selecting decision thresholds, using logistic-regression analysis, using discriminant-function analysis, or incorporating the tool into a clinical strategy by using decision analysis.
Urinary neopterin as a predictive marker of coronary artery abnormalities in Kawasaki syndrome
Authors: Iizuka T , Minatogawa Y , Suzuki H , Itoh M , Nakamine S , Hatanaka Y , Uemura S , Koike M 
Published: January 2020

Abstract
We investigated whether urinary neopterin concentrations respond to the pathological conditions (especially coronary artery dilatation) of Kawasaki syndrome. All of 29 children with Kawasaki syndrome had very high urinary neopterin concentrations. Increased urinary neopterin concentrations coincided with fever and with monocytosis in peripheral blood. The urinary neopterin excretion peaking within the first 8 days after onset correlated with the development of coronary artery dilatation. Increased urinary neopterin concentrations indicate that cell-mediated immunity is activated in patients with Kawasaki syndrome. Endogenous interferon-gamma and activation of monocytes/macrophages may play a role in the pathogenesis of Kawasaki syndrome. Not only do neopterin concentrations correlate with symptoms in the acute phase of Kawasaki syndrome, they also act as a predictive marker of coronary artery abnormalities in affected patients.
"Direct" and total bilirubin tests: contemporary problems
Authors: Lott J A , Doumas B T 
Published: January 2020

Abstract
In eight unique challenges mailed by The College of American Pathologists Comprehensive Chemistry Survey to participating laboratories within 3 years, results for direct-reacting bilirubin (DBIL) were highly variable among the 12 largest peer groups, and most of the results differed greatly from the values obtained by a referred method. Peer-group mean values for total bilirubin (TBIL) were in much better agreement with each other and with those obtained by the Reference Method for TBIL. From a review of the information on the assay of DBIL provided to us by the manufacturers, we conclude that among the major causes of the large variability and bias in DBIL assays are problems with calibration, lack of a serum blank measurement, inadequate concentrations of HCl in the reaction mixture, inappropriate use of bichromatic correction methods, and possibly the use of wetting agents or surfactants in the reagent. Within-group SDs were small and generally acceptable. The among-peer-group variability in DBIL values is attributable to bias, not imprecision. We recommend several simple changes that could improve the accuracy of DBIL determinations in clinical laboratories.
Enzyme immunoassay--a new technique for estimating hemoglobin A1c
Authors: John W G , Gray M R , Bates D L , Beacham J L 
Published: January 2020

Abstract
We describe a method for estimating hemoglobin A1c (HbA1c) with a commercially available enzyme immunoassay system. The method is based on microtiter plate technology, utilizing an antibody raised to hemoglobin, the epitope being the Amadori product of glucose plus the first eight amino acids on the N-terminal end of the beta chain of hemoglobin. The enzyme immunoassay displays good within-batch (CV 2.3-2.4%) and between-batch (CV 2.6-5.0%) precision, and the results were not affected by different types of anticoagulant. The method was linear within the expected range of results and showed good correlation (r = 0.88-0.98) with established methods for estimating glycohemoglobin. Using this method, we obtained a reference interval of 2.8-4.9% (central 95%) for HbA1c in a nondiabetic population. The percentages of hemoglobin that were HbA1c in diabetics (6.86% +/- 2.51%) were significantly greater (P &lt; 0.001) than in nondiabetics (3.46% +/- 0.52%).
Differences in elastase-binding activity of alpha 1-protease inhibitor and alpha 2-macroglobulin for asthma patients and control subjects with various alpha 1-protease inhibitor phenotypes
Authors: Gaillard M C , Reichberg S B , Nogueira C M , Kilroe-Smith T A 
Published: January 2020

Abstract
Forty-two adult patients with asthma and 30 control subjects were investigated for elastase-binding capacities of alpha 1-protease inhibitor and alpha 2-macroglobulin in plasma. The binding activities of alpha 1-protease inhibitor and alpha 2-macroglobulin in asthmatic patients with the M phenotype for the alpha 1-protease inhibitor differed in their relationship to the values in control subjects with the same phenotype [less alpha 1-protease inhibitor for asthmatics (35.1 +/- 1.8) than for controls (42.9 +/- 2.0 kU/L) (P &lt; 0.001); more alpha 2-macroglobulin for asthmatics (6.9 +/- 0.3) than for control subjects (5.9 +/- 0.4 kU/L) (P &lt; 0.03)]. In contrast, the patients with a deficiency allele (S, V, or Z) for alpha 1-protease inhibitor had lower activities of both alpha 1-protease inhibitor [22.1 +/- 0.1 vs 42.9 +/- 2.0 kU/L (P &lt; 0.001)] and alpha 2-macroglobulin [4.6 +/- 0.6 vs 5.9 +/- 0.4 kU/L (P &lt; 0.001)] than did the control subjects with the M phenotypes. The relevance of the results to the pathogenesis of asthma is discussed.
Increased phospholipase A activities in sera of intensive-care patients show sn-2 specificity but no acyl-chain selectivity
Authors: Püttmann M , Aufenanger J , von Ochsenstein E , Dürholt S , van Ackern K , Harenberg J , Hoffmann G E 
Published: January 2020

Abstract
Phospholipase A (PLA) activities were measured by high-performance liquid chromatography in two enzyme preparations purified from human duodenal juice and a serum pool as well as in 52 sera from 31 intensive-care patients with various diseases. On the basis of a position-specific fatty acid analysis of the natural substrate ("soybean lecithin") from a commercial PLA kit, serum activities of PLA1 could be clearly distinguished from those of PLA2, which is not possible in the usual measurements made with single-label radioactive substrates. Independent of the type of disease, all sera with highly increased PLA activities (40-200 U/L) showed nearly pure PLA2 characteristics without any preference among oleic, linoleic, and linolenic acid in the sn-2 position of the glycerophospholipid substrate. Nevertheless, very low PLA1 activities (&lt; or = 5 U/L, most likely due to heparin perfusion therapy) could also be detected by palmitic and stearic acid release from the sn-1 position, leading to small changes in fatty acid release patterns of sera with low PLA activities. Measurements with sera from heparin-treated volunteers demonstrated that heparin therapy may initially contribute as much as 22 U/L to increased PLA1 activities but is not important under prolonged therapy. The absence of selectivity with respect to acyl-chain desaturation supports the concept of serum PLA2 as an acute-phase protein rather than a regulator of the arachidonic acid cascade.
Analysis for bismuth in tissue by electrothermal atomic absorption spectrometry
Authors: Slikkerveer A , Helmich R B , de Wolff F A 
Published: January 2020

Abstract
We developed a simple method for the analysis of bismuth (Bi) in biological tissue, using wet digestion for sample pretreatment. Bi was determined by electrothermal atomic absorption spectrometry with platinum as a matrix modifier to decrease the volatility of Bi. The furnace program included a gas stop for sensitivity enhancement. Analytical performance was established for Bi in kidney, liver, brain, and bone. As little as 25 ng/g wet weight can be detected in the most concentrated digests. Homogenization of bone was necessary before digestion, and its matrix showed the strongest interference. In rats exposed orally to colloidal bismuth subcitrate for 14 days, the metal could be detected in liver, kidney, and spleen but not in brain and bone. In the tissues of 12 patients who died from non-Bi-related causes, no Bi were present in kidney in the other 2.
Intra- and interlaboratory sources of imprecision in drug measurements by different techniques
Authors: Tsanaclis L M , Wilson J F 
Published: January 2020

Abstract
We compared the intra- and interlaboratory precision of seven techniques used to measure eight antiepileptic drugs, digoxin, and theophylline by using data from the international Healthcontrol external quality-assessment scheme. Scheme participants were supplied blind with 6 or 12 sets of duplicate lyophilized serum samples. Each set contained different drug concentrations, and duplicates were analyzed separately, 1 to 6 months apart. The intra- and interlaboratory components of assay variance were isolated and compared by Bartlett's test for homogeneity of variance. Fluorescence polarization immunoassay (Abbott) showed the best overall intra- and interlaboratory performance for a range of analytes. The largest intralaboratory errors were produced by techniques using the Syva EMIT assays. Our analysis of the data shows that for most analyte/technique combinations, intralaboratory sources of variation were more important than interlaboratory sources. Gains in assay precision will therefore result from attention to internal laboratory procedures.
Reduced bovine hemoglobin solution evaluated for use as a blood gas quality-control material
Authors: Mahoney J J , Wong R J , Van Kessel A L 
Published: January 2020

Abstract
We evaluated a new commercially available partially purified reduced bovine hemoglobin solution (RBHS) and a new tonometer for use in the quality control of blood gas analyzers. RBHS is manufactured in three different formulations, each corresponding to three different bicarbonate-buffering capacities and concentrations of total hemoglobin (ctHb). The P50 for each formulation of RBHS was determined to be as follows: 30.6 mmHg (4.08 kPa) for Level 1, 29.1 mmHg (3.88 kPa) for Level 2, and 28.2 mmHg (3.76 kPa) for Level 3. When RBHS and human blood samples were tonometered at three clinically significant values of PO2 and PCO2, the recovered values for PO2 and PCO2 in RBHS were comparable with those of the tonometered whole blood. Each level of RBHS also produced precise pH (SD &lt; or = 0.006 pH units) and ctHb (SD = 1.0 g/L) values. In addition, when the temperature of a sample chamber was intentionally altered, the changes in RBHS blood gas values closely approximated the changes seen with human blood. RBHS shows more thermal sensitivity than either perfluorocarbon emulsions or aqueous buffers, which are currently being used as quality-control and proficiency testing materials.
Monitoring cancer antigen 125 in serum of ovarian cancer patients after administration of 131I-labeled F(ab')2 fragments of OC125 antibody
Authors: Reinsberg J , Schultes B , Wagner U , Krebs D 
Published: January 2020

Abstract
We evaluated the effect of repeated administration of OC125 F(ab')2 fragments on cancer antigen (CA) 125 determination in 210 serum samples from 30 patients. We found falsely high CA 125 concentrations in 142 (68%) samples, using a homologous CA 125 enzyme immunoassay (EIA) with OC125 antibodies. The Truquant OV2 method, which involves two other murine antibodies, and the IMx CA 125 method, which uses sheep antibodies as capture antibodies, resulted in only slightly increased (false-positive) values in some samples with exceptionally high CA 125 EIA values. We measured falsely low CA 125 values in 37 (18%) samples with the Truquant OV2 method. Interferences could be eliminated by removal of serum IgG. Our results suggest that interferences are to some extent caused by anti-idiotypic IgG induced by OC125 administration. Assays involving nonmurine anti-CA 125 antibodies as capture antibodies seem to be most suited for CA 125 determination after OC125 treatment, but in every case an apparent increase of CA 125 after OC125 infusion should be validated.
Candidate reference methods for determining target values for cholesterol, creatinine, uric acid, and glucose in external quality assessment and internal accuracy control. II. Method transfer
Authors: Thienpont L M , Leenheer A P , Stöckl D , Reinauer H 
Published: January 2020

Abstract
We describe the testing of transferability of candidate Reference Methods developed by INSTAND for cholesterol, creatinine, uric acid, and glucose. The methods are based on isotope dilution-gas chromatography--mass spectrometry. The study consisted of two parts: setup of the methods and self-evaluation for readiness in the collaborating laboratory, followed by independent measurements in parallel with INSTAND. Criteria used for judging the transferability and general reliability of the candidate Reference Methods were: the accuracy and precision of the collaborating laboratory and the agreement between the two laboratories. The accuracy was judged from the results on the Standard Reference Material 909 from the National Institute of Standards and Technology. For all analytes except glucose the bias from the certified value was &lt; 0.7%. The mean intralaboratory imprecision ranged from 0.66% to 1.24%. The agreement between the results was tested by an advanced linear-regression analysis and Student's t-test. In general, the results demonstrate that the candidate Reference Methods developed by INSTAND can be successfully transferred without loss of their inherent precision and accuracy.
Dipyrone interference on several common biochemical tests
Authors: Gascón N , Otal C , Martínez-Brú C , Mercé J , Cortés M , Arcelus R , Queraltó J M , Sánchez J M , González-Sastre F 
Published: January 2020

Abstract
We studied the effect in vitro and in vivo of dipyrone on the determination of several biochemical tests in two analyzers, a Hitachi 747 and a Kodak Ektachem 700. From studies in vitro, we found significant interference by dipyrone (P &lt; 0.05) in the determination of creatine kinase (CK), lactate dehydrogenase (LD), uric acid, triglycerides, cholesterol, aspartate aminotransferase, alanine aminotransferase, and urea nitrogen with both instruments, and in the determination of creatinine in the Ektachem analyzer. We also studied the effect of intravenously administered dipyrone in 14 patients. Dipyrone interfered significantly (P &lt; 0.05) in the determination of CK, LD, uric acid, triglycerides, and cholesterol with both instruments, and creatinine only with the Ektachem analyzer. Using high-performance liquid chromatography (HPLC), we measured concentrations of dipyrone in the serum of patients who had received the drug and observed a negative correlation between the concentrations of dipyrone in the blood and the percentage of each analyte concentration.
Determination of trace elements in blood serum of patients with Behçet disease by total reflection x-ray fluorescence analysis
Authors: Dogan P , Dogan M , Klockenkämper R 
Published: January 2020

Abstract
The distribution of trace elements Fe, Cu, Zn, Se, and Rb was determined in sera from patients with the complete type of Behçet disease in the active stage and from healthy controls. Total reflection x-ray fluorescence was used for quantitative analysis; in general, atomic absorption spectrometry was used only for control of the Se values. Zn, Se, and Rb concentrations were significantly (P &lt; 0.0001) lower for patients than for control subjects. No significant difference was determined in the Fe content. However, there was a significant increase in Cu in the patients so that the ratios Cu/Zn, Cu/Se, and Cu/Rb were significantly higher for the patients than for the control subjects (P &lt; 0.0001).
Sandwich enzyme immunoassay of osteocalcin in serum with use of an antibody against human osteocalcin
Authors: Monaghan D A , Power M J , Fottrell P F 
Published: January 2020

Abstract
We have developed and thoroughly validated a solid-phase sandwich enzyme-linked immunosorbent assay (ELISA) on microtiter plates for osteocalcin in human serum with use of an antibody raised against human osteocalcin. We used a monoclonal antibody against bovine osteocalcin as the capture antibody; the second antibody was a polyclonal antibody against human osteocalcin. The amount of bound second antibody was determined with use of swine anti-rabbit antibody labeled with horseradish peroxidase. We demonstrated independence of volume and determined the recovery of added standard and within- and between-assay precision. The minimal detection limit for osteocalcin was between 1.0 and 1.5 micrograms/L and the midpoint of the standard curve ranged from 14 to 17 micrograms/L. The intraassay CV was &lt; or = 8% in the range 2.7-52 micrograms/L; the interassay CV was usually &lt; or = 15% in the same range. Analytical recovery of human osteocalcin standard added to serum samples was consistently &gt; 90%. Values for osteocalcin measured in serum from 44 normal subjects were similar to those obtained with a competitive enzyme immunoassay (EIA) that used a monoclonal antibody against bovine osteocalcin. There was a good correlation between the two assays [r2 = 0.877, slope and intercept (+/- SE) = 0.88(+/- 0.051) and 0.316(+/- 0.523), respectively]. The range and mean (+/- SD) for the sandwich ELISA and the competitive EIA were 1.7-18.1 micrograms/L [8.7(+/- 4.4) micrograms/L] and 1.9-22.8 micrograms/L [9.1(+/- 4.4) micrograms/L], respectively.
Development and evaluation of an osteocalcin chemiluminoimmunoassay
Authors: Kao P C , Riggs B L , Schryver P G 
Published: January 2020

Abstract
We developed a competitive chemiluminoimmunoassay of osteocalcin that is similar to radioimmunoassay but uses acridinium-ester-labeled antigen instead of 125I-labeled osteocalcin; a second antibody immobilized on plastic beads is used to separate free and bound fractions. There was good correlation of the new chemiluminoimmunoassay (y) with a polyclonal antiserum (R102) radioimmunoassay (x) used in many previous clinical studies (r = 0.96, y = 0.968x + 2.69, Sy/x = 0.029, n = 86). The new assay recognized both the intact and the small fragment of osteocalcin in plasma and detected decreases of them (total, approximately 47%) after a 24-h infusion of parathyroid hormone. Patients with primary hyperparathyroidism had increased concentrations of intact osteocalcin. Children had higher concentrations of osteocalcin than adults did. Healthy women had greater osteocalcin concentrations at ages 50-70 years than earlier. Inverse correlations of bone mineral density and osteocalcin were found in healthy women and in women with osteoporosis.
Wheat germ lectin affinity electrophoresis of serum alkaline phosphatase with commercially available agarose gels
Authors: Mattiazzo M , Ramasamy I 
Published: January 2020

Abstract
We have modified a commercially available procedure involving precast agarose gels (Paragon Isopal System) to measure alkaline phosphatase (EC 3.1.3.1) isoenzymes. Including wheat germ lectin in the equilibration buffer improved the resolution of the bone and liver isoenzymes. Unlike previously described wheat germ lectin affinity electrophoresis methods, the procedure measures bone, liver, and biliary isoenzymes in a single step. There was good correlation between the affinity electrophoresis and the neuraminidase preincubation methods for the measurement of bone (r = 0.958) and liver (r = 0.962) alkaline phosphatase isoenzymes. However, the affinity electrophoresis method also quantified minor isoenzyme fractions that were poorly resolved by the neuraminidase method. The method is technically simple, reproducible, and capable of rapid handling of large workloads.
Measuring alveolar lavage fluid surfactant by fluorescence polarization
Authors: McCarroll N A , Van Lente F 
Published: January 2020

Abstract
We describe a procedure by which surfactant/albumin ratios in bronchoalveolar fluid (BALF) may be quantified with the Abbott Laboratories TDx fluorescence polarization analyzer and fetal lung maturity reagents. Adding albumin to BALF samples shifted the surfactant/albumin ratios to within the analytical range of the method. The analytical CV for assay of modified BALF samples was 2.9%. Ratios obtained for modified samples from normal individuals (n = 10), transplanted lungs (n = 23), and contralateral native lungs of the transplant recipients (n = 23) were significantly different (P = 0.006). The ratio obtained for these modified samples can be converted, if needed, to the ratio in the original sample by using a simple mathematical relationship and the albumin concentration of the sample. We propose that this ratio will be useful in evaluating the surfactant status of BALF, particularly in lung allografts.