bluuebunny/crossref_metadata_2025_split huggingface dataset:
Intracellular and extracellular blood magnesium fractions in hemodialysis patients; is the ionized fraction a measure of magnesium excess?
Authors: Huijgen Henk J , Sanders Renata , van Olden Rudolf W , Klous Marjolein G , Gaffar Faryal R , Sanders Gerard T B 
Published: January 2020

AbstractTo establish the best measure for determining magnesium overload, we measured ionized and total magnesium in serum and mononuclear blood cells and total magnesium in erythrocytes in blood of 23 hemodialysis patients, known for their disturbed magnesium homeostasis. When comparing the mean magnesium values obtained in the patient population with those of a control population, all of these magnesium markers, including the biologically active fractions, were significantly (P &lt;0.05) increased. Because serum total magnesium was not increased in all dialysis patients studied, the population was divided into two groups, according to total serum magnesium &gt;1.0 mmol/L or less than that. Results in these two populations showed that ionized serum magnesium and ionized magnesium in mononuclear blood cells might give a better indication about the magnesium status of the tested patients than the currently used total serum magnesium data. However, neither of the two markers, especially ionized serum magnesium, was able to discriminate fully between normal magnesium homeostasis and magnesium excess. We therefore conclude that the two ionized magnesium markers offer minimal advantage for this discrimination, and that the total magnesium concentration in serum remains the measurement of choice.
Multicenter evaluation of the Bayer Immuno 1™ CA 15-3™ assay
Authors: Cheli Carol D , Morris Deborah L , Kish Linda , Goldblatt Joan , Neaman Irene , Allard W Jeffrey , Yeung Kwok K , Wu Alan H B , Moore Robert , Chan Daniel W , Fritsche Herbert A , Schwartz Morton K , Very Donald L 
Published: January 2020

Abstract
We conducted a multicenter evaluation of the analytical and clinical features of the automated Bayer Immuno 1™ CA 15-3™ assay and compared assay performance to two manual tests. Results of the 10-day imprecision study of the Bayer Immuno 1 assay pooled across four evaluation sites and three lots of reagent produced total CV ≤4%. Lot-to-lot reproducibility for 26 different lots of reagents and calibrators manufactured over a 2-year period was demonstrated (CV, 1.1%). Results for the Bayer Immuno 1 assay correlated well with the Biomira TRUQUANT® BR™ 27.29 and Centocor® CA 15-3 RIAs (r ≥0.94). The upper limit of the reference interval for the Bayer Immuno 1 assay was 35.9 kilounits/L (35.9 units/mL); values were similar for all methods. Longitudinal monitoring of healthy women yielded assay values with an average CV of 11% and 21% for the Bayer Immuno 1 and Biomira assays, respectively. The Bayer Immuno 1 assay demonstrated the analytical features, intermethod correlation, and long-term performance characteristics that are essential for longitudinal monitoring of breast cancer patients.
Clinical laboratory test menu changes in the Pacific Northwest: 1994 to 1996
Authors: LaBeau Kathleen M , Simon Marianne , Steindel Steven J 
Published: January 2020

Abstract
Laboratory testing services are presently undergoing dynamic changes in response to a wide range of external factors. Government regulations, reimbursement, and managed care are only a few of the influences affecting the availability of testing services and on-site testing capabilities in hospital, independent, and physician office laboratories. Medical practice changes, marketplace influences, test technologies, and costs also play a role in determining where testing is being performed. To better understand the factors influencing clinical laboratory test volumes and menus and to identify on-site testing deemed essential in physician office laboratories, we gathered information from a network of clinical laboratories in the Pacific Northwest. Questionnaires were sent to 257 Laboratory Medicine Sentinel Monitoring Network participants in March 1996. In the past 2 years, changes in on-site test volumes and test menus have been primarily due to medical practice changes and marketplace influences. When laboratories had a decrease in test volumes or test menu choices, the size of the patient workload and the volumes of test orders have had the greatest impact. Laboratory regulations and managed care contracts have played a role in shifting on-site testing to outside sources; however, these factors did not appear to be primary influences. Only 5% of physician office laboratories identified tests that they believed were essential for optimal patient care but did not perform on-site.
Immunoradiometric assay for the N-terminal fragment of proatrial natriuretic peptidein human plasma
Authors: Numata Yoshito , Dohi Keiji , Furukawa Ayako , Kikuoka Shino , Asada Hidehisa , Fukunaga Takahiro , Taniguchi Yasushi , Sasakura Kazuyuki , Tsuji Tetsuo , Inouye Ken , Yoshimura Michihiro , Itoh Hiroshi , Mukoyama Masashi , Yasue Hirofumi , Nakao Kazuwa 
Published: January 2020

Abstract
Recently, the N-terminal fragment of proatrial natriuretic peptide (N-terminal proANP) has been proposed as a marker of chronic congestive heart failure. In this study, we established a two-step immunoradiometric assay using monoclonal antibodies and synthetic N-terminal proANP (1–67) as a standard. It allows us to measure plasma N-terminal proANP in only 4 h without prior extraction. The detection limit of this assay was 15 pmol/L for a 100 μL sample of plasma. Within-run CVs ranged from 1.7% to 2.9% and between-run CVs ranged from 4.2% to 5.1%. The dilution curves of plasma samples showed good linearity and analytical recovery was 89–104%. The mean (±SD) N-terminal proANP in plasma of 33 healthy subjects was 188 (±71) pmol/L and 1030 (±411) pmol/L in 25 patients with heart failure. Our immunoradiometric assay is rapid and precise enough for routine determination of N-terminal proANP in human plasma.
Flow cytometry with a monoclonal antibody to the low density lipoprotein receptor compared with gene mutation detection in diagnosis of heterozygous familial hypercholesterolemia
Authors: Raungaard Bent , Heath Finn , Brorholt-Petersen Jens Uffe , Jensen Henrik Kjærulf , Faergeman Ole 
Published: January 2020

AbstractWe used a fluorescence flow cytometry assay with a monoclonal low density lipoprotein (LDL) receptor-specific antibody to detect LDL receptor expression on blood T lymphocytes and monocytes. We prepared peripheral blood mononuclear cells from patients with genetically verified LDL receptor-defective (Trp66-Gly mutation, n = 17) or receptor-negative (Trp23-stop mutation, n = 17) heterozygous familial hypercholesterolemia (FH) and from healthy individuals (n = 24). The cells were stimulated to express the maximum amount of LDL receptor by preincubation in lipoprotein-deficient medium. A dual-labeling technique allowed flow cytometric analysis of LDL receptor expression on cells identified by fluorescently conjugated surface marker antibodies. Knowing the LDL receptor gene mutation of the FH patients allowed us to compare the diagnostic capability of this functional assay with the DNA diagnosis and to validate the assay with molecular genetics instead of clinical indices of heterozygous FH. T lymphocytes expressed more LDL receptors and gave better diagnostic results than monocytes, and cells from patients with either the Trp66-Gly or the Trp23-stop mutation had variable but significantly reduced LDL receptor expression. The data indicate that this fluorescence flow cytometry assay is unsuitable for diagnosis of individual cases of heterozygous FH but that it may be useful for functionally characterizing mutations in the LDL receptor gene.
Marked gender differences in ambulatory morning growth hormone values in young adults
Authors: Engström Britt Edén , Karlsson F Anders , Wide Leif 
Published: January 2020

Abstract
The influence of gender on serum concentrations of growth hormone (GH) and 12 other endocrine analytes was investigated in sera drawn from 291 healthy medical students in the ambulatory state in the morning, after fasting overnight. GH was measured with a sensitive noncompetitive fluoroimmunoassay. The median GH value was 80-fold higher in women 21–26 years old than in age-matched men (14.4 vs 0.18 mIU/L), compared with a female/male ratio of 2.2 for 17β-estradiol and a male/female ratio of 14 for testosterone. Furthermore, the values for sex hormone-binding globulin, follicle-stimulating hormone, luteinizing hormone, prolactin, and insulin-like growth factor 1 (IGF-1) were higher, whereas the values for free thyroxine, triiodothyronine, thyroid-stimulating hormone, and parathyroid hormone were lower in the women. The median GH value was 68-fold higher in women 27–43 years old than in age-matched men (10.9 vs 0.16 mIU/L). Women taking contraceptives with ethinyl estradiol and desogestrel or levonorgestrel had higher GH values, and the desogestrel group had lower IGF-1 values than women not taking contraceptives. The median GH values in these groups were 125- and 117-fold higher, respectively, than in men 21–26 years old. The results suggest that routine morning activity produces a marked GH response in &gt;90% of young women but in very few age-matched men. The effect on GH was even more pronounced in women taking oral contraceptives, suggesting that the intake of ethinyl estradiol contributes to higher GH concentrations in these women.
Simultaneous determination of mycophenolic acid and its glucuronide in human plasma using a simple high-performance liquid chromatography procedure
Authors: Shipkova Maria , Niedmann Paul Dieter , Armstrong Victor William , Schütz Ekkehard , Wieland Eberhard , Shaw Leslie M , Oellerich Michael 
Published: January 2020

Abstract
We describe a reversed-phase HPLC method for determination of total mycophenolic acid (MPA), its free concentration (MPAf), and the glucuronide metabolite (MPAG), based on simple sample preparation and gradient elution chromatography. The compounds were quantified in parallel by absorbance at 254 nm and 215 nm in the internal standard mode. Linearity was verified up to 50 mg/L for MPA and up to 500 mg/L for MPAG (r &gt;0.999). Detection limits at 215 and 254 nm were, respectively, 0.01 and 0.03 mg/L for MPA, and 0.03 and 0.1 mg/L for MPAG. The recovery of MPA was 95–106%;recovery of MPAG was 96–106%. The imprecision (CV) for MPA (0.2–25 mg/L) was &lt;8.4% (254 nm) and &lt;4.4% (215 nm) within day (n = 12) and &lt;9.2% (254 nm) and &lt;6.2% (215 nm) between days (n = 12). The imprecision for MPAG (10–250 mg/L) was &lt;4.9% (254 nm) and &lt;3.4% (215 nm) within day, and &lt;6.1% (254 nm) and &lt;5.9% (215 nm) between days. For quantification of MPAf, 100 μL of ultrafiltrate was applied directly to the column. The detection limit was 0.005 mg/L at 215 nm and 0.015 mg/L at 254 nm. In the range between 18–210 μg/L, the within-day CVs were &lt;11.8% (n = 12) and the between-day CVs were &lt;15.8% (n = 12).
Genetic testing for Gilbert’s syndrome: how useful is it in determining the cause of jaundice?
Authors: Rudenski Aram S , Halsall David J 
Published: January 2020

Abstract
Gilbert’s syndrome is a benign condition causing hyperbilirubinemia, which is also a symptom of liver or hemolytic disease. A genetic test may be possible for Gilbert’s syndrome because an associated gene defect has been isolated. Here we present a mathematical analysis of the use of this test in excluding harmful causes of hyperbilirubinemia. The effectiveness of the test depends on a low prevalence and high penetrance of the gene defect and a low prevalence of harmful hyperbilirubinemia. If the gene defect has a 12% prevalence and 10% penetrance, then the prevalence of harmful hyperbilirubinemia needs to be &lt;1.5% for a positive test to reduce this risk fivefold. Estimates of the prevalence of harmful hyperbilirubinemia and of the prevalence and penetrance of the Gilbert genotype are required to assess the value of the genetic test in determining a cause of hyperbilirubinemia. Until these values for prevalence and penetrance are known, genetic testing for Gilbert’s syndrome cannot be recommended on a routine basis.
Identification and haplotype analysis of apolipoprotein B-100 Arg3500→Trp mutation in hyperlipidemic Chinese
Authors: Tai Der-Yan , Pan Ju-Pin , Lee-Chen Guey-Jen 
Published: January 2020

AbstractDNA screening for apolipoprotein (apo) B-100 mutations was performed in hyperlipidemic Chinese. The apo B-100 gene segment surrounding previously identified familial defective apo B-100 (FDB) mutations was amplified by PCR and subjected to single-strand conformation polymorphism (SSCP) analysis. One subject’s aberrant SSCP band was cloned and sequenced to study the molecular lesions. A recurrent ArgCGG-to-TrpTGG mutation (R3500W) in the codon 3500 of the apo B-100 gene was identified. The C-to-T transition creates a NlaIII site and permits rapid restriction analysis of the mutation. A total of 373 hyperlipidemic patients and 309 controls were screened for R3500W. Nine unrelated subjects were shown to be heterozygous for the mutation, and no R3500W carriers were found in the control group (P = 0.004). Six polymorphic markers, including five restriction fragment length polymorphisms and one hypervariable repeat region, were used for haplotype analysis on the mutant allele. In two families, the R3500W mutation could be unambiguously assigned to a unique haplotype XbaI−/MaeI+/MspI+/EcoRI+/Eco57I+/34 3′HVR repeats; in the other seven unrelated heterozygotes, this finding was consistent when an unequivocal haplotype was deduced. The results suggest that all R3500W alleles are identical by descent in our population. The fact that the same mutant allele was identified in other Asians with FDB indicates a common Asian origin for the R3500W mutations.
Biochemical markers of the acute coronary syndromes
Authors: Christenson Robert H , Azzazy Hassan M E 
Published: January 2020

AbstractThe acute coronary syndromes represent a continuum of myocardial ischemia ranging from angina, reversible tissue injury → unstable angina, frequently associated with minor myocardial damage → myocardial infarction and extensive tissue necrosis. Historically, coronary artery disease assessment has been mainly binary, using WHO criteria of symptoms, electrocardiography, and biochemical markers. The creatine kinase-MB isoenzyme (CK-MB) has been a benchmark for markers, but it is not specific for myocardium. Cardiac-specific isoforms of troponin T and I have emerged as sensitive myocardial infarction (MI) indicators and, importantly, for risk stratification of acute coronary syndrome patients. In addition to markers of myocardial cell necrosis, markers of plaque disruption (C-reactive protein and serum amyloid A), “angry” platelets (P-selectin), ischemia (glycogen phosphorylase-BB isoenzyme), and the procoagulant state and thrombosis (soluble fibrin) have potential use. Also, CK-MB and myoglobin have been combined with clinical indicators for monitoring reperfusion after thrombolytic therapy. Biochemical markers will continue to be an important clinical adjunct for MI diagnosis, risk assessment, and reperfusion monitoring in the future.
Coronary atherosclerosis and its effect on cardiac structure and function: evaluation by electron beam computed tomography
Authors: Stanford William , Thompson Brad H 
Published: January 2020

AbstractCoronary artery disease affects millions of Americans annually. In evaluating coronary artery disease, it is important to develop diagnostic methodology that can screen patients before the onset of symptoms or cardiac events and, in addition, evaluate the functional aspects of coronary artery disease, including any residual effects on the heart after events have occurred. Electron beam computed tomography allows the identification of coronary calcium, which is a marker for coronary atherosclerotic disease, and also allows the quantification of cardiac function, which may be altered from coronary atherosclerosis or the occurrence of a cardiac event. Thus, electron beam computed tomographic imaging is having a major impact on the diagnosis and follow-up on coronary artery disease.
Evaluation of the tacrolimus II microparticle enzyme immunoassay (MEIA II) in liver and renal transplant recipients
Authors: Cogill Jan L , Taylor Paul J , Westley Ian S , Morris Raymond G , Lynch Stephen V , Johnson Anthony G 
Published: January 2020

Abstract
We evaluated the MEIA II with blood samples with added tacrolimus (3.0, 5.0, 11.0, and 22.0 μg/L). The assay had acceptable recoveries (99–103%) and intraday imprecision (&lt;16.0%) across the range of concentrations studied, except for the recoveries at 3.0 μg/L (86.3%) and 5.0 μg/L (80.7%). Comparison of liver (n = 116) and renal (n = 113) patient samples measured by MEIA II against HPLC-tandem mass spectrometry (HPLC-MS/MS) found a mean overestimation of 15.6%. From these comparison data it can be calculated that at values of 5 and 20 μg/L in liver or renal transplant patient samples, measured by HPLC-MS/MS, MEIA II will have the corresponding range estimates of 3.6–7.9 μg/L and 20.9–25.4 μg/L, respectively. No clinically significant difference in results, in terms of overestimation or correlation, was observed between the two transplant groups studied. The MEIA II is an improvement on the previous MEIA I and is suitable for the therapeutic drug monitoring of tacrolimus where HPLC-MS/MS is unavailable.
Serum digoxin in the presence of Digibind: determination of digoxin by the Abbott AxSYM and Baxter Stratus II immunoassays by direct analysis without pretreatment of serum samples
Authors: Ocal Idris T , Green Terrence R 
Published: January 2020

Abstract
We have reevaluated the feasibility of using direct immunochemical methods to track free digoxin in patients receiving Digibind®. We report here that results obtained by the Stratus II and AxSYM immunoassays on patients receiving digoxin (without Digibind), digoxin-fortified serum samples supplemented with Digibind, and a digitoxic patient treated with Digibind, show no clinically significant biases. We conclude that useful free digoxin concentrations may be obtained for Digibind-treated patients using either the AxSYM or Stratus immunoassays without subjecting samples to ultrafiltration before analysis.
Luminometric single step urea assay using ATP-hydrolyzing urease
Authors: Näslund Birgitta , Ståhle Lars , Lundin Arne , Anderstam Björn , Arner Peter , Bergström Jonas 
Published: January 2020

AbstractAn automatic enzyme kinetic luminometric method for determination of small quantities of urea in biological fluids and in microdialysates is presented. The method is based on the ATP-hydrolyzing urease reaction [urea amidohydrolase (ATP-hydrolyzing); EC 3.5.1.45], monitored by a luciferin-luciferase ATP reaction. The assay range is 100 pmol to 50 nmol with a detection limit of 5 μmol/L in the sample, compared with detection limits of 0.1 mmol/L in earlier spectrophotometric methods. To reduce the non-urea-dependent ATPase activity (vblank) and to increase the urea-dependent activity, 1,2-propanediol was included. Assay conditions were optimized by multivariate analysis. Recoveries of urea added to blood dialysate and plasma were 96–103%. No analytical interference of common metabolites, drugs, or other additives was observed. The total CVs (6 days and six concentrations, 1.2–21.8 mmol/L) were 3.6–8.5%. The results obtained with the present assay were highly correlated for dialysate (r = 0.979) and for plasma (r = 0.978) with those obtained by a spectrophotometric kit method with slopes of 1.02–1.03 and intercepts of 0.08–0.23 mmol/L.
Evaluation of Interferences in Rate and Fixed-Time Nephelometric Assays of Specific Serum Proteins
Authors: Bossuyt Xavier , Blanckaert Norbert 
Published: January 2020

Abstract
We performed interference studies for IgG, IgA, IgM, haptoglobin, and α1-antitrypsin assayed in serum, using either fixed-time nephelometry on the BN 100 from Behring or rate nephelometry on two analyzers from Beckman Instruments. For clear serum samples, results for IgG, IgA, IgM, and haptoglobin obtained with the three nephelometers showed good agreement. Values for α1-antitrypsin in clear sera were lower with the BN 100 than with the Array 360 or Immage. In lipemic samples, the BN 100 gave higher values than the Array 360 or Immage for all analytes except IgG. Addition of Intralipid to serum produced atypical reactions with the BN 100 (fixed-time nephelometry) but not with the Array 360 or Immage (rate nephelometry). The interference of lipemia on the BN 100 was also seen when the Beckman antibody was used, indicating that the effect was reagent-independent. For hemolyzed samples, the BN 100 gave higher values than the Array 360 or Immage for haptoglobin but not for the other analytes. Addition of increasing amounts of a hemolysate to serum revealed a negative interference in all assay systems. This effect was more pronounced with the Beckman reagent than with the Behring reagent in all three nephelometers and was independent of the type of instrument (fixed-time vs rate nephelometry).
Real-Time Quantitative PCR for the Measurement of MYCN Amplification in Human Neuroblastoma with the TaqMan Detection System
Authors: Raggi Claudia Casini , Bagnoni Maria Letizia , Tonini Gian Paolo , Maggi Mario , Vona Giovanna , Pinzani Pamela , Mazzocco Katia , De Bernardi Bruno , Pazzagli Mario , Orlando Claudio 
Published: January 2020

AbstractBackground: Neuroblastoma is the most common extracranial malignant solid tumor in children under 5 years and is characterized by a wide clinical and biological heterogeneity, from spontaneously regressive forms to cancers with a rapid and fatal progression. MYCN oncogene amplification is considered the most important prognostic factor to evaluate survival and therapeutic choices in these patients.Methods: Here we present a new assay for rapid and accurate measurement of MYCN amplification, based on real-time quantitative PCR with the TaqManTM reaction. The degree of MYCN amplification was derived from the ratio of the MYCN oncogene and the single-copy reference gene, β-actin. The absolute abundance of these two genes in tumor sample DNA was obtained by extrapolation on external calibration curves generated with reference DNA.Results: We found a variable degree of MYCN amplification, from 2 to 29, in 26 of 49 (53%) neuroblastomas. These results were well correlated to those obtained with a competitive PCR assay in the same samples (r = 0.987). MYCN amplification was associated mainly with advanced cancer stages, and the analysis of overall survival confirmed that the measurement of MYCN amplification is a predictor of patient outcome in neuroblastoma. Patients without MYCN amplification had a cumulative survival significantly higher than patients with low (&lt;9; P = 0.02) and high (≥9; P = 0.03) oncogene amplification.Conclusion: The assay is rapid and reproducible and does not require any post-PCR analytical procedure.