bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of two homogeneous methods for measuring high-density lipoprotein cholesterol
Authors: Huang Yi-Chang , Kao Jau-Tsuen , Tsai Keh-Sung 
Published: January 2020

AbstractWe evaluated the performance of two homogeneous assays for quantifying HDL cholesterol (HDL-C) and compared them with the phosphotungstic acid (PTA)/MgCl2 assay. Both homogeneous HDL-C assays were precise, having a within-run CV of &lt;1.20% and a between-run CV of &lt;4.07%. The HDL-C values (y) measured by the two homogeneous methods correlated well with those by the PTA/MgCl2 method (x): y = 1.00x + 64.98 mg/L, r = 0.987, Sy|x = 27.99 mg/L (n = 152) for the polyethylene glycol-modified enzymes/α-cyclodextrin sulfate (PEGME) assay (Kyowa), and y = 0.84x + 106.51 mg/L, r = 0.984, Sy|x = 26.10 mg/L (n = 152) for the polyanion–polymer/detergent (PPD) assay (Daiichi). The specificity of the PEGME method seemed better than that of the PPD method, as the PPD method was markedly interfered with by supplemental LDL-C. Addition of 20 g/L triglycerides produced a negative error of ∼18% in both homogeneous assays. Bilirubin and hemoglobin had little influence on the PEGME method; hemoglobin had little effect on the PPD method. Bilirubin, however, markedly decreased the readings by the PPD method. We found the PEGME assay superior to the PPD assay for routine HDL-C testing, because the PPD assay is relatively inaccurate and not specific.
Reference values for retinol, tocopherol, and main carotenoids in serum of control and insulin-dependent diabetic Spanish subjects
Authors: Olmedilla Begoña , Granado Fernando , Gil-Martinez Enrique , Blanco Inmaculada , Rojas-Hidalgo Enrique 
Published: January 2020

AbstractTo establish reference ranges for use in clinical and epidemiological studies, we determined concentrations of retinol, α-tocopherol, β-carotene, α-carotene, β-cryptoxanthin, lutein, zeaxanthin, and lycopene in 450 Spanish control subjects and 123 Spanish patients with insulin-dependent diabetes mellitus (IDDM). Results were grouped according to sex, and samples were collected throughout the year. Concentrations of retinol were significantly lower and β-carotene and α-carotene were higher in women than in men, both in controls and IDDM subjects, whereas β-cryptoxanthin concentrations were higher only in control women. Conditional logistic regression analysis showed that retinol, β-carotene, and lycopene were the variables associated with diabetes. In comparison with other populations, our controls showed, in general, ordinary concentrations of retinol, comparatively low β-carotene and high β-cryptoxanthin concentrations, and a relatively high α-tocopherol/cholesterol ratio.
Platelet distribution width for differential diagnosis of thrombocytosis
Authors: Osselaer Jean-Claude , Jamart Jacques , Scheiff Jean-Marie 
Published: January 2020

AbstractDifferential diagnosis of thrombocytosis is not always obvious. The routine clinical chemistry laboratory classically provides only limited help in distinguishing between reactive thrombocytosis (RT) and autonomous thrombocytosis, where platelet production escapes normal regulatory processes, and which is seen in myeloproliferative diseases (MPD) such as essential thrombocythemia and polycythemia vera. We explored the clinical use of platelet distribution width (PDW) in the differential diagnosis of thrombocytosis. During a 3-month period, 250 patients presenting with a platelet count &gt;500 × 109/L were studied; 174 were classified as having RT, 42 had a diagnosis of MPD, and 34 patients were excluded because they had a hemopathy different from MPD, and either did or did not present a known etiologic factor for RT. First, we determined that in the RT group the value of PDW was closely linked to both mean platelet volume (MPV) and platelet count (PLT) (PDW = 79.5 − 0.005 PLT − 3.5 MPV; r = 0.848, R2 = 0.720). Therefore a new parameter, PDWresidual, was defined (PDWresidual = PDWobserved − PDWexpected). Second, the discrimination between reactive and autonomous thrombocytosis obtained with PDWresidual was compared with that obtained with either PDW, MPV, or PLT. PDWresidual proved much more powerful than each of the other parameters used separately: 76% of MPD patients had a PDWresidual above the 95th percentile value of the RT population and none of the MPD patients had a PDWresidualbelow the 50th percentile. Thus, the combined interpretation of PLT, MPV, and PDW through the use of a PDWresidualappears highly useful in the differential diagnosis of thrombocytosis. Also, through simple modeling, more information can be drawn from parameters such as PDW that hitherto were mostly discarded as being without clinical interest.
Enzyme immunoassay for measuring 25-hydroxyvitamin D3 in serum
Authors: Lind Charlotte , Chen Jiewei , Byrjalsen Inger 
Published: January 2020

AbstractWe developed a rapid, competitive enzyme immunoassay (EIA) for measuring 25-hydroxyvitamin D3 [25(OH)D3] in serum. The EIA was based upon 25(OH)D3-3-hemisuccinate covalently coupled to secondary amino groups grafted onto the polystyrene surface of microtiter wells. Optimal coupling conditions were established, and we found that inclusion of 40 μmol/L chloramine T, an agent not previously described for use in coupling to these plates, resulted in both more reproducible coupling as well as more than a twofold increase in the coupling efficiency. Before EIA, 25(OH)D3 was extracted from the serum samples by acetonitrile, and the redissolved extract was incubated with polyclonal rabbit antibody raised against 1,25-dihydroxyvitamin D3-3-hemisuccinate conjugated to bovine serum albumin. Peroxidase-labeled antibody raised in goat against rabbit immunoglobulins was used for detection. The detection limit of the EIA was 4.4 μg/L; recovery 102%; on-plate CV 11%; within-run CV including extraction 12%, and between-run CV 15%. There was no clinically important cross-reactivity with other vitamin D metabolites, and results obtained by the EIA were compared with results obtained by a previously described RIA.
Growth hormone (GH) assays: influence of standard preparations, GH isoforms, assay characteristics, and GH-binding protein
Authors: Jansson Chatarina , Boguszewski Cesar , Rosberg Sten , Carlsson Lena , Albertsson-Wikland Kerstin 
Published: January 2020

Abstract
The impact of the adoption of the new biosynthetic growth hormone (GH) WHO International Reference Preparation (IRP 88/624), and the recommendation to report results in μg/L instead of mU/L, is described. Conversion factors were determined by comparing both the linear and nonlinear relations of the GH values. The Pharmacia polyclonal IRMA (p-IRMA) and the DELFIA® monoclonal time-resolved immunofluorometric assay (trIFMA) with kit calibrators calibrated either against the pituitary-derived WHO IRP 80/505 or the new 88/624 were evaluated. Conversion factors of 4.17 mU/L = 1 μg/L for the p-IRMA and 4.31 mU/L = 1 μg/L for the trIFMA were necessary. Different cross-reactivity patterns for the deaminated and dimer 22-kDa, 20-kDa, and 17-kDa GH isoforms were found. Expected GH recovery was similar when the measured values were adjusted according to the results of the cross-reactivity study.
Cardiac troponin I, cardiac troponin T, and creatine kinase MB in dialysis patients without ischemic heart disease: evidence of cardiac troponin T expression in skeletal muscle
Authors: McLaurin Mary D , Apple Fred S , Voss Ellen M , Herzog Charles A , Sharkey Scott W 
Published: January 2020

AbstractSerum cardiac troponin T (cTnT) concentrations are frequently increased in chronic dialysis patients as measured by the first-generation ELISA immunoassay, as is creatine kinase (CK) MB mass in the absence of acute ischemic heart disease. We designed this study to compare four serum markers of myocardial injury [CK-MB mass, first-generation ELISA cTnT, second-generation Enzymun cTnT, and cardiac troponin I (cTnI)] in dialysis patients without acute ischemic heart disease. We also evaluated skeletal muscle from dialysis patients as a potential source of serum cTnT. No patients in the clinical evaluation group (n = 24) studied by history and by physical examination, electrocardiography, and two-dimensional echocardiography had evidence of ischemic heart disease. Biochemical markers were measured in serial predialysis blood samples with specific monoclonal antibody-based immunoassays. For several patients at least one sample measured above the upper reference limit: CK-MB, 7 of 24 (30%); ELISA cTnT, 17 of 24 (71%); Enzymun cTnT, 3 of 18 (17%); and cTnI, 1 of 24 (4%). In a separate group of dialysis patients (n = 5), expression of cTnT, but not cTnI, was demonstrated by Western blot analysis in 4 of 5 skeletal muscle biopsies. Chronic dialysis patients without acute ischemic heart disease frequently had increased serum CK-MB and cTnT. The specificity of the second-generation cTnT (Enzymun) assay was improved over that of the first-generation (ELISA) assay; cTnI was the most specific of the currently available biochemical markers. cTnT, but not cTnI, was expressed in the skeletal muscle of dialysis patients.
Cardiac troponin I and T alterations in hearts with severe left ventricular remodeling
Authors: Ricchiuti Vincent , Zhang Jianyi , Apple Fred S 
Published: January 2020

AbstractCardiac troponin T (cTnT) and troponin I (cTnI) have been suggested as new, more specific markers of myocardial cellular damage. The objective of this study was to examine how the distributions of cTnI and cTnT were affected in postinfarction left ventricular remodeled (LVR) myocardium. At 2 months postinfarct in a porcine heart failure model, both Western blot and biochemical assay analyses were performed on left ventricular myocardium remote from the infarct zone in ligation animals (n = 8). Results were compared with data from the left ventricular myocardium from similar sized healthy (control) pigs (n = 7). Autoradiograms from Western blot analysis showed that the protein mass for cTnI and cTnT in LVR hearts decreased 80% (P &lt;0.001) and 40% (P &lt;0.02), respectively, when compared with nondiseased tissue. Similarly, the concentrations for cTnI and cTnT in LVR hearts decreased 42% (P &lt;0.05) and 70% (P &lt;0.001), respectively, compared with nondiseased normal tissue. The clinical assumption is that the appearance of cTnI and cTnT in the blood is proportional to chronic loss of cTnI and cTnT from injured myocardium associated with left ventricular remodeling.
Microalbuminuria and borderline-increased albumin excretion determined with a centrifugal analyzer and the Albumin Blue 580 fluorescence assay
Authors: Kessler Manfred A , Meinitzer Andreas , Petek Walter , Wolfbeis Otto S 
Published: January 2020

Abstract
We report a new automated fluorescence assay for determination of albumin in urine. The dye Albumin Blue 580 specifically binds to albumin with exhibition of strong red fluorescence. The albumin concentration is calculated from emission intensity at 616 nm (excitation at 590 nm) and a calibration curve. Two Cobas Fara programs cover working ranges of 2–200 and 1–50 mg/L with detection limits of 1.4 and 0.4 mg/L, respectively. Within-run CVs (n = 10) ranged from 1.7% (189 mg/L) to 8.9% (7.2 mg/L) for 2–200 mg/L and from 2.9% (43.3 mg/L) to 5.7% (2.3 mg/L) for the 1–50 mg/L range. A test of urine samples (n = 100) submitted to routine analysis gave results that agreed well with those by the Behring nephelometric assay: AB 580 = 0.922 (± 0.010) BNA + 4.16 (± 0.78). No interference was detected from other urine components, including several proteins and 46 drugs. The high specificity and sensitivity make the method ideal for determination of microalbuminuria. In addition, the method is fast, inexpensive, and well-suited for clinical laboratory application and thus may be used instead of immunoassays.
Methods for detection of point mutations: performance and quality assessment
Authors: Nollau Peter , Wagener Christoph , Division on behalf of the IFCC Scientific , Techniques Committee on Molecular Biology 
Published: January 2020

Abstract
We give an overview of current methods for the detection of point mutations as well as small insertions and deletions in clinical diagnostics. For each method, the following characteristics are specified: (a) principle, (b) major modifications, (c) maximum fragment size that can be analyzed, (d) ratio and type of mutations that can be detected, (e) minimum ratio of mutant to wild-type alleles at which mutations can be detected, and (f) detection methods. Special attention is paid to the possibilities of quality assessment and the potential for standardization and automation.
Simple triple-label detection of seven cystic fibrosis mutations by time-resolved fluorometry
Authors: Heinonen Pia , Iitiä Antti , Torresani Toni , Lövgren Timo 
Published: January 2020

Abstract
We describe a simple hybridization assay performed in microtitration wells with use of DNA probes labeled with three different lanthanide chelates for detection of seven mutations that cause cystic fibrosis. The assay is based on DNA amplification of four fragments containing the mutations (ΔF508, G1717→A, G542X, R553X, 3905 insertion T, W1282X, and N1303K) by PCR, followed by hybridization with short, allele-specific oligonucleotide probes labeled with europium, terbium, or samarium chelates. Because the technology makes it possible to hybridize three DNA probes simultaneously in one reaction, all 14 mutation-related alleles were detected in a total of five reaction wells. Blood spot specimens, obtained from children with cystic fibrosis, their parents, and their siblings, have been assayed, and for all the probes the positive signal-to-noise ratios are &gt;10. Solution hybridization utilizing triple-label time-resolved fluorometry combined with PCR is a suitable procedure for large-scale screening and automation.
Analytical and clinical evaluation of the Immulite® estradiol assay in serum from patients undergoing in vitro fertilization: estradiol increase in mature follicles
Authors: Dancoine François , Couplet Gisèle , Buvat Jacques , Guittard Catherine , Marcolin Gérard , Fourlinnie Jean-Claude 
Published: January 2020

Abstract
We examined an immunoassay for estradiol (E2) on the Immulite®—an automated, random access chemiluminescent immunoassay system—to determine its accuracy and precision required for in vitro fertilization (IVF) studies. The assay, which has a reportable range from 73 to 7300 pmol/L, demonstrated good linearity under dilution, a detection limit of 44 pmol/L, and interassay CVs of 12.6% and 7.6% at 466 and 6164 pmol/L, respectively. In a retrospective analysis of 545 serum samples, the assay showed adequate agreement with an antibody-coated-tube RIA. The two E2 assays showed good agreement, even on samples from patients receiving a variety of different estrogen replacement therapies. Longitudinal studies of individual IVF cycles showed good parallelism between the automated system and the RIA, and results by the automated assay correlated well with the total number of follicles.
Mass spectrometric characterization of nicked fragments of the β-subunit of human chorionic gonadotropin
Authors: Liu Chuanliang , Bowers Larry D 
Published: January 2020

Abstract
We describe the use of an HPLC/MS technique for the characterization of nicked fragments of hCG β-subunit. After reductive alkylation of the nicked hCG β-subunit with vinylpyridine, endoproteinase Glu-C or trypsin was used to digest the protein to produce peptides that could be analyzed by HPLC/electrospray ionization MS. Human leukocyte elastase digestion was used to produce an experimentally nicked hCG. Two nicking sites were observed, between amino acids 42Thr and 43Arg and between 44Val and45Leu. The former site has not been previously reported for elastase digestion. The structures of the fragments were confirmed by HPLC/MS after removal of the oligosaccharide by direct mass measurement and by mass determination of their proteolytic digests. Without the glycopeptidase treatment, the microheterogeneity of the two N-linked oligosaccharides could be deduced from the spectra of the proteolytic fragments. Nicking with elastase was found to alter the oligosaccharide structures. Nicked β-subunit samples isolated from the urine of choriocarcinoma patients were also analyzed and the location of the nicking site(s) agreed with that determined by classical techniques. Important differences in the oligosaccharide structures were also observed in these samples, including the presence of triantennary oligosaccharides not found in hCG from healthy subjects. These findings demonstrate the potential of HPLC/MS for characterization of glycoprotein standard preparations.
Correlation between plasma 5-aminolevulinic acid concentrations and indicators of oxidative stress in lead-exposed workers
Authors: Costa Cristine A , Trivelato Gilmar C , Pinto Adriana M P , Bechara Etelvino J H 
Published: January 2020

Abstract5-Aminolevulinic acid (ALA), a heme precursor accumulated in acute intermittent porphyria and lead poisoning, undergoes metal-catalyzed aerobic oxidation at physiological pH to yield reactive free radical species (O2−·&gt;, HO·, and ALA·). We analyzed the relationships between plasma ALA concentrations, blood concentrations of lead, protoporphyrin IX (PP-IX), superoxide dismutase (SOD), and methemoglobin (metHb), and urine chemiluminescence (CL) in samples collected from lead-exposed workers. All variables measured were substantially (P &lt;0.01) higher (2–8-fold) in the lead-exposed workers (n = 60). Plasma ALA concentrations were, on average, 6-fold higher in lead-exposed workers. We observed positive linear relationships between ALA and lead (r = 0.992), ALA and PP-IX (r = 0.891), ALA and metHb (r = 0.984), lead and SOD (r = 0.948), ALA and urine CL (r = 0.987), and lead and PP-IX (r = 0.993). These data are consistent with our free radical hypothesis for lead poisoning, where ALA distribution to and accumulation in several organs may trigger oxidative stress responses.
Endocrine aspects of anabolic steroids
Authors: Wu F C W 
Published: January 2020

Abstract
Understanding of the mechanism of androgen action has been enhanced by advances in knowledge on the molecular basis of activation of the androgen receptor and the importance of tissue conversion of circulating testosterone to dihydrotestosterone and estradiol. New evidence supports the view that supraphysiological doses of anabolic steroids do have a definite, positive effect on muscle size and muscle strength. However, the nature of the anabolic action of androgens on muscle is currently unclear and may involve mechanisms independent of the androgen receptor. The dose–response relationships of anabolic actions vs the potentially serious risks to health of androgenic-anabolic steroids (AAS) use are still unresolved. Most of the adverse effects of AAS are reversible but some are permanent, particularly in women and children. The reported incidence of acute life-threatening events associated with AAS abuse is low, but the actual risk may be underrecognized or underreported; the exact incidence is unknown. The long-term consequences and disease risks of AAS to the sports competitor remain to be properly evaluated.
Immunoprocedures for detecting human chorionic gonadotropin: clinical aspects and doping control
Authors: Stenman Ulf-Håkan , Unkila-Kallio Leila , Korhonen Juha , Alfthan Henrik 
Published: January 2020

Abstract
The pregnancy hormone human chorionic gonadotropin (hCG) is also present at low concentrations in plasma and urine of men and nonpregnant women. hCG immunoreactivity occurs in various molecular forms: Besides the intact hCG heterodimer, considerable amounts of proteolytically cleaved forms, free subunits, and fragments are found in plasma and urine. Especially in urine, proteolytic fragments constitute a major part of the hCG immunoreactivity. The different forms of hCG cross-react to various degrees in immunoassays and constitute a problem for standardization of specific hCG determinations. After injection of hCG (10 000 IU of Pregnyl®; Organon), above-normal concentrations of hCG can be detected in serum and urine for 7–11 days. Most immunoassays for hCG also measure hCGβ. Quantitative hCG determinations are mainly performed on serum samples, and very few commercial hCG determinations have been validated for determination of urine samples. Considerable care must therefore be exercised when utilizing such assays to analyze urines for doping control.
Counterpoint To (measure apo)B or not to (measure apo)B: a critique of modern medical decision-making
Authors: Sniderman Allan D 
Published: January 2020

Abstract
The measurement of apo B provides critical information that is complementary to that provided by the plasma and lipoprotein lipids for the assessment of coronary risk and the choice of appropriate pharmacological therapy. Why then is this measurement not in more widespread clinical use? I suggest two explanations. First, against the evidence, there is a lingering perception that problems persist in its measurement in routine clinical practice. Far from this being the case, however, the measurement of apo B has met every reasonable standard of laboratory precision and reliability to allow its widespread introduction in clinical laboratories. The second impediment is that the introduction of new tests has become subject to the authority of consensus conferences, a new approach to medical decision-making. The number of such conferences is increasing astronomically, and their reports are major determinants of clinical practice and allocation of resources. Notwithstanding the benefits they have brought, here I argue that, just as with any other scientific method, the merits of this new method of decision-making need to be examined critically; for if we do not, a process that was established to introduce change may, in fact, retard it or destroy it altogether.
Extraction of glyceric and glycolic acids from urine with tetrahydrofuran: utility in detection of primary hyperoxaluria
Authors: Dietzen Dennis J , Wilhite Timothy R , Kenagy David N , Milliner Dawn S , Smith Carl H , Landt Michael 
Published: January 2020

Abstract
Primary hyperoxaluria (PH) is an autosomal recessive metabolic abnormality characterized by excessive oxalate excretion leading to nephrocalcinosis and progressive renal dysfunction. Type I primary hyperoxaluria (PH I) results from a deficiency of alanine:glyoxylate aminotransferase, whereas type II disease has been traced to a deficiency of d-glycerate dehydrogenase. The two syndromes are often distinguished on the basis of organic acids that are coexcreted with oxalate: glycolate and l-glycerate in type I and type II disease, respectively. Routine organic acid analysis with diethyl ether extraction followed by gas chromatographic analysis failed to detect normal and increased concentrations of these diagnostic metabolites. Subsequent extraction of urine with tetrahydrofuran (THF), however, extracted 75% of added glycerate, 42% of added glycolate, and 75% of added ethylphosphonic acid (internal calibrator). THF extraction was analytically sensitive enough to allow determination of normal excretion of glycolate (14–72 μg/mg creatinine) and glycerate (0–5 years, 12–177 μg/mg creatinine and &gt;5 years, 19–115 μg/mg creatinine). Four of five patients with PH I and both patients with type II disease were correctly identified. Thus, THF extraction is a convenient adjunct to routine organic acid analysis and facilitates the detection of PH.