bluuebunny/crossref_metadata_2025_split huggingface dataset:
Standardization of pyridinium crosslinks, pyridinoline and deoxypyridinoline, for use as biochemical markers of collagen degradation
Authors: Robins S P , Duncan A , Wilson N , Evans B J 
Published: January 2020

Abstract
The collagen crosslinks, pyridinoline and deoxypyridinoline, have been developed as urinary markers of bone resorption but, despite wide clinical application of the technique, comparatively little attention has been paid to the standardization of these compounds. In this study, pyridinoline and deoxypyridinoline have been purified from bone and converted completely to monochloride trihydrochloride salts. In addition to mass spectrometry and NMR spectroscopy, the purity of the isolated materials was assessed by microelemental analysis including the chloride counterions. These purified compounds were used to establish individual molar absorptivity values as primary standardization criteria for the two crosslinks. For pyridinoline in 0.1 mol/L HCl, epsilon at 295 nm was 5490 L mol(-1) cm(-1); in 50 mmol/L sodium phosphate, pH 7.5, epsilon at 325 nm was 5785. The corresponding values for deoxypyridinoline at acid and neutral pH were 5160 and 5290 L mol(-1) cm(-1). The availability of standardization criteria for the crosslinks will allow more meaningful comparisons of clinical data between different laboratories.
Simple spectrofluorometric determination of p-aminobenzoic and p-aminosalicylic acids in biological fluids by use of terbium-sensitized luminescence
Authors: Lianidou E S , Ioannou P C 
Published: January 2020

Abstract
A novel, sensitive, and selective method has been developed for determination of p-aminobenzoic (PABA) and p-aminosalicylic (PAS) acids in the N-benzoyl-L-tyrosyl-PABA/ PAS test. PAS is measured as a ternary complex with terbium and EDTA (lambda(ex) = 324 nm, lambda(em) = 546 nm) in alkaline aqueous solution (pH approximately 12.6), whereas both compounds (PABA and PAS) are measured as ternary complexes with terbium and tri-n-octylphosphine oxide (lambda(ex) = 292 nm, lambda(em) = 546 nm) in weakly acidic aqueous solution (pH approximately 5.5). We inve stigated and implemented optimum conditions for formation of these complexes, yielding respective detection limits for PABA and PAS of 0.07 and 0.02 micromol/L and ranges of application of 0-10 and 0-40 micromol/L (final concentration). The method has been successfully applied to determinations of PABA and PAS in urine and, after alkaline hydrolysis, to determinations of PABA in serum that has been deproteinized with acetonitrile. Within-run imprecision of the PABA determination ranges from 0.8% to 4.2 % for urine samples and from 3.9% to 8.2% for serum samples; day-to-day imprecision varies from 3.2% to 10% for serum samples.
Changes in serum apolipoprotein and lipoprotein profile induced by chronic alcohol consumption and withdrawal: determinant effect on heart disease?
Authors: Lecomte E , Herbeth B , Paille F , Steinmetz J , Artur Y , Siest G 
Published: January 2020

Abstract
The effects of alcohol consumption on serum concentrations of apolipoproteins (apo) A-I, C-III, B, and E and of lipoproteins (Lp) A-I, A-I:A-II, C-III, C-III:B, and (a) were studied in 132 healthy subjects, including 55 low drinkers of alcohol (&lt;20 g/day), 36 moderate drinkers (20-50 g/day), and 41 heavy drinkers (&gt;50 g/day), and in 97 hospitalized alcoholic patients (&gt; 100 g/day) without severe liver disease (especially functional insufficiency), before and after 21 days of withdrawal treatment. Serum concentrations of apo A-I, LpA-I, LpA-I:A-II, apo C-III, and LpC-III significantly (P &lt;/= 0.01) increased with alcohol intake (mean +/- SE in low drinkers vs in alcoholics)--1.45 +/- 0.03 vs 1.78 +/- 0.05 g/L; 0.45 +/- 0.02 vs 0.56 +/- 0.02 g/L; 0.99 +/- 0.02 vs 1.22 +/- 0.04 g/L; 27.6 +/- 1.5 vs 39.7 +/- 1.7 mg/L; and 8.4 +/- 0.9 vs 24.7 +/- 1.7 mg/L, respectively-whereas apo B and LpC-III:B concentrations tended to decrease--1.20 +/- 0.04 vs 1.06 +/- 0.04 g/L and 19.3 +/- 1.2 vs 14.9 +/- 1.0 mg/L, respectively. No significant difference between these four types of alcohol consumption was noticed for cholesterol, triglycerides, apo E, and Lp(a). After withdrawal, the concentrations of serum apo A-I, apo C-III, LpA-I, LpA-I:A-II, and LpC-III decreased significantly (P &lt;/= 0.01), reaching values comparable with those in low drinkers; concentrations of triglycerides, apo B, apo E, and Lp(a) rose; and cholesterol concentration was unaffected. In multiple regression analysis, after adjustment for serum concentrations of albumin, aspartate aminotransferase, and gamma-glutamyltransferase and for the Quetelet index, alcohol consumption remained positively correlated to apo A-I, LpA-I:A-II, apo C-III, and LpC-III concentrations. Study of other determinants of serum apo and lipoprotein concentrations suggests that alcohol-related variations in some of them, especially apo A-I, might depend on the metabolic ability of the liver to synthesize proteins and on induction phenomena. Finally, although the increase of antiatherogenic apo- and lipoproteins and the decrease of those known to be atherogenic were generally marked in alcoholics, alcohol-related modifications of these markers were very limited in our sample of French healthy men. We conclude, therefore, that moderate alcohol consumption (20-50 g/day) is unlikely to protect against ischemic heart disease through an effect on the proteins measured in this study.
Design and assessment of average of normals (AON) patient data algorithms to maximize run lengths for automatic process control
Authors: Westgard J O , Smith F A , Mountain P J , Boss S 
Published: January 2020

Abstract
Achieving high quality and high productivity with automated testing processes will require process control systems that are optimized for the necessary error detection, minimum false rejection, and maximum run length. This study investigates whether run length could be monitored by average of normals (AON) algorithms that truncate the patient test distribution and estimate the average of a suitable number of patient results. The design of AON algorithms for individual analytes is facilitated by computer-simulated power curves that consider the ratio of the population biological variation (Spop) to the test method variation (Smeas), represent a range of Spop/Smeas ratios from 2 to 15, and include numbers of patient test results from 10 to 600. The potential applications of AON algorithms are assessed for 38 tests whose quality requirements represent the total error criteria from the Ontario Medical Association Laboratory Proficiency Testing Program, Spop/Smeas ratios from 0 to 32, critical systematic shifts from 0.02 to 10.85 Smeas, and test workloads representative of a regional reference laboratory. Approximately half of these tests provide high potential for applying AON algorithms to monitor run length.
Competitive RT-PCR to quantify CFTR mRNA in human endometrium
Authors: Mularoni A , Adessi G L , Arbez-Gindre F , Agnani G , Nicollier M 
Published: January 2020

Abstract
Because the down-regulation by progesterone of cystic fibrosis transmembrane conductance regulator (CFTR) expression could be a useful specific marker to define the state of implant receptivity in endometrium, a competitive reverse transcription-polymerase chain reaction (RT-PCR) was developed for quantifying the CFTR mRNA concentration in human endometrial samples. A competitor RNA was constructed with the same sequence as the CFTR sequence except for a 20-nucleotide insertion in the middle. The amplified products were separated by polyacrylamide gel electrophoresis. The ratio of CFTR band areas to competitor band areas provided the basis of quantification. Using this competitive RT-PCR, we measured CFTR mRNA in human endometrial samples taken at different periods of the menstrual cycle, in endometriosis, and in hyperplasia. Results show that the method is suitable for measuring the concentration of CFTR mRNA.
Chemiluminescence immunoassay for vascular endothelial growth factor (vascular permeability factor) in tumor-tissue homogenates
Authors: Schlaeppi J M , Eppenberger U , Martiny-Baron G , Küng W 
Published: January 2020

Abstract
We developed a two-site chemiluminescence immunoassay for human vascular endothelial growth factor (VEGF). The assay recognized both VEGF121 and VEGF165 isoforms, but had no detectable cross-reactivity with platelet-derived growth factor or placenta growth factor. The range of detection was between 30 ng/L and 30 micrograms/L VEGF. Inter- and intraassay variations were 8.2-8.3% and 7.2-7.6%, respectively. VEGF concentrations were measured in the cytosolic extracts of 45 ovarian and 142 primary breast tumors. The amount of VEGF in the ovarian tumors (median = 0.46 ng/mg total protein, range 0-15.8 ng/mg) was significantly (P = 0.03) higher compared with the breast tumors (median = 0.24 ng/mg total protein, range 0-12.3 ng/mg). In 32 and 7 extracts of normal breast tissues adjacent and distant to the tumors, respectively, VEGF concentrations were significantly much lower (P &lt; 0.0001). The detection of substantial amounts of VEGF in two invasive tumors (compared with normal tissues) suggests that the assay should be a useful tool for investigating the prognostic value of VEGF in breast and ovarian carcinomas and for selecting patients for future anti-VEGF therapy.
Prostate-specific antigen concentrations in serum in acute illnesses
Authors: Honda S A , Goldstein A P , Morita T , Sugiyama C , Cody L , Rios C N , Bhagavan N V 
Published: January 2020

Abstract
In light of recent studies showing that prostate-specific antigen (PSA) complexes with certain blood proteins, we studied the effects of acute-phase reactants and alpha 2-macroglobulin (A2MG) on serum concentrations of PSA. Serum samples were obtained from 419 men admitted to an acute-care facility. Various acute-phase reactants-including C-reactive protein, alpha 1-acid glycoprotein, alpha 1-antitrypsin, and alpha 1-antichymotrypsin-and A2MG were measured with a Beckman Array analyzer in parallel with determinations of PSA concentrations by two methods, the Hybritech Tandem RIA and the Abbott PSA IMx. Evaluation by Spearman rank correlation revealed a significant negative correlation of A2MG with PSA values (P &lt; 0.01) and (as expected) a positive correlation of age with PSA values (P &lt; 0.001). The former correlation suggests the possibility that patients with high serum concentrations of A2MG may give falsely decreased results for PSA concentrations in serum.
Growth hormone assays: early to latest test generations compared
Authors: L'Hermite-Balériaux M , Copinschi G , Van Cauter E 
Published: January 2020

Abstract
We compared the data from four growth hormone (GH) immunoassays for analyzing 24-h GH profiles in four apparently normal subjects and four obese subjects (508 serum samples). The detection limit was 0.02 microgram/L for one immunochemiluminometric assay (ICMA), 0.1 microgram/L for two IRMAs, and 0.4 microgram/L for one RIA. All GH pulses with a peak ICMA value &gt; 1 microgram/L were detected by each of the other methods. Overall, the correlation coefficient between the values obtained with all four assays exceeded 0.90. However, for GH concentrations &lt; or = 0.25 microgram/L, acceptable concordance (r2 &gt; or = 0.80) was reached only between the ICMA and one IRMA; between the ICMA and the RIA, concordance was acceptable only for GH concentrations &gt; or = 10 micrograms/L. In the normal subjects, the percentage of undetectable values was 0% with the ICMA but 29% with one of the IRMAs; in obese subjects, the corresponding values were 12% and 38%.
Comparison of total and bone-specific alkaline phosphatase in patients with nonskeletal disorder or metabolic bone diseases
Authors: Woitge H W , Seibel M J , Ziegler R 
Published: January 2020

Abstract
To evaluate the diagnostic validity of new assays for bone-specific alkaline phosphatase (BAP), we compared measurements of total alkaline phosphatase (TAP) in serum with results for three different assays of serum BAP in healthy adults (n = 119), patients with chronic nonskeletal disorders (n = 123), and patients with metabolic bone diseases (n = 113). Serum TAP was determined by a standard colorimetric assay, BAP by the methods of lectin precipitation (L-BAP), enzyme immunoassay (E-BAP), and immunoradiometric assay (I-BAP). Impairment of liver function resulted in significant increases of all alkaline phosphatase (AP) measurements, with the smallest changes being exhibited by E-BAP. Compared with the results by TAP, diagnostic sensitivity (i.e., of values exceeding the reference interval) was not improved by BAP, but receiver-operating characteristic (ROC) curve analyses revealed improved discrimination for primary hyperparathyroidism by E-BAP. These results indicate that, in the presence of liver disease, the specificity of AP measurements is improved by measuring BAP. In most other clinical situations, serum TAP appears to provide sufficient clinical information; however, the cross-sectional study design used here allows no statement about the usefulness of BAP in serial measurements.
Microtiter plate immunoenzymometric assay for estrogen receptor
Authors: Delage V , Teulon J M , Bellanger L , Seguin P , Descotes F , Saez S 
Published: January 2020

Abstract
The estrogen receptor (ER) status of breast cancer is used both as a prognostic factor and as a predictor of response to endocrine therapy. An immunoenzymometric assay for ER was developed on 96-well microtiter plates (EIA96). This technique involves two monoclonal antibodies directed against different epitopes in the B domain of ER. The two-step protocol (16-18 h and 3 h at 4 degrees C) requires 100 microL of cytosol. This assay showed a detection limit of 0.58 pmol/L. Intra- and interassay CVs of clinical specimens were &lt; or = 5% except for the least concentrated sample (6.5 pmol/L, CV = 6.7%). In a comparison study involving cytosols of breast adenocarcinoma tissue biopsies, we compared the EIA96 with the radioligand assay (RLA) and the Abbott ER-EIA, widely used techniques for determining ER concentration in cytosols of breast cancer tumors. The two EIAs showed excellent agreement; however, two samples showed discrepant results by EIA96 and RLA.
Epitope mapping of prostate-specific antigen with monoclonal antibodies
Authors: Jette D C , Kreutz F T , Malcolm B A , Wishart D S , Noujaim A A , Suresh M R 
Published: January 2020

Abstract
Prostate-specific antigen (PSA) is a widely used marker for screening and monitoring prostate cancer. We identified and characterized the epitopes of two anti-PSA monoclonal antibodies (mAbs) designated B80 and B87. The epitopes were initially mapped as nonoverlapping by developing a sandwich immunoassay to measure PSA with the two anti-PSA mAbs. The two antibodies do not cross-react with homologous pancreatic kallikrein, but recognize epitopes unique to PSA. B80 and B87 can recognize both free and complexed PSA and hence measure total PSA. Epitope scanning and bacteriophage peptide library affinity selection procedures were used to identify and locate an epitope on PSA. A possible epitope for B80 was identified as being located on or near PSA amino acid residues 50-58 (-GRH-SLFHP-). The epitope for B87 was likely on an exposed nonlinear conformational determinant, unique to PSA, and not masked by the binding of B80 or alpha 1-antichymotrypsin.
Radioimmunoprecipitation assay for glutamic acid decarboxylase antibodies evaluated clinically with sera from patients with insulin-dependent diabetes mellitus
Authors: Ohta M , Obayashi H , Takahashi K , Kitagawa Y , Nakano K , Matsuo S , Nishimura M , Itoh N , Ohta K 
Published: January 2020

Abstract
We evaluated a new, commercially developed radioimmunoprecipitation assay for measuring glutamic acid decarboxylase (GAD) antibodies by using recombinant human GAD65. The intra- and interassay CVs were 8.0% (n = 20) and 8.6% (n = 15), respectively. We found GAD antibodies in 74% (23 of 31; 95% confidence interval 55-88%), 70% (14 of 20; 46-88%), and 65% (28 of 43; 49-79%) of patients at, respectively, &lt; or = 1 year, 1-2 years, and 2-4 years after the onset of insulin-dependent diabetes mellitus (IDDM) and in 30% (30 of 99; 21-40%) of patients with long-term diabetes (4-22 years). We also detected GAD antibodies in 8% (9 of 106; 4-16%) of patients with non-insulin-dependent diabetes mellitus (NIDDM). The frequency of GAD antibodies in the NIDDM group was markedly higher in the insulin-deficient patients [67% (6 of 9; 30-93%)], who initially were nonketotic and non-insulin-dependent for &gt; or = 6 months but later became insulin dependent, than in the non-insulin-deficient patients [3% (3 of 97; 1-9%)]. This new commercial assay is easy to use and provides a specific and sensitive method for evaluating GAD antibodies in IDDM.
Pre beta 1-high-density lipoprotein increases in coronary artery disease
Authors: Miida T , Nakamura Y , Inano K , Matsuto T , Yamaguchi T , Tsuda T , Okada M 
Published: January 2020

Abstract
Pre beta 1-HDL promotes cholesterol efflux from cell membranes. Its plasma concentration is regulated by lecithin: cholesterol acyltransferase (LCAT). To clarify whether the concentration of pre beta 1-HDL changes in coronary artery disease (CAD), we determined the distribution of apolipoprotein A-I (apoA-I) among HDL subfractions in 20 CAD patients and 20 healthy controls, using nondenaturing two-dimensional gel electrophoresis. We found that CAD patients had significantly higher concentrations of pre beta 1-HDL than the controls [7.6% +/- 3.4% vs 4.6% +/- 2.3% of apoA-I (P &lt; 0.01)]. Even after correcting for apoA-I concentrations, this increase remained significant [87 +/- 37 vs 63 +/- 28 mg/L apoA-I (P &lt; 0.05)]. The mean LCAT concentration was significantly lower (P &lt; 0.05) in CAD patients than in controls. These findings, that pre beta 1-HDL concentrations increase in CAD, strongly suggest that the process of reverse cholesterol transport could be altered in CAD.
Rapid determination of fecal fat by Fourier transform infrared analysis (FTIR) with partial least-squares regression and an attenuated total reflectance accessory
Authors: Franck P , Sallerin J L , Schroeder H , Gelot M A , Nabet P 
Published: January 2020

Abstract
Fecal lipid content is usually determined by titrimetric or gravimetric methods, but these methods are time consuming and involve dangerous solvents. We have developed a new method of measuring fecal lipids by Fourier transform infrared spectrometry (FTIR) with an attenuated total reflectance accessory that is fast and requires no solvents. The spectra of stools from 4000 to 750 cm-1 were analyzed, and the lipid concentrations were measured by using a calibration curve prepared by partial least-squares analysis of data from 34 stools. The linearity of the method was tested by mixing low-lipid stools with lipid-overloaded stools to give a range of 0.5-15% lipid. The prediction residual values were -0.49-0.78% for calibrators, and -2.55-2.34% for unknown samples. There was good agreement between the fecal lipids measured by gravimetric (x) and FTIR(y) methods: y = 0.87x + 5.5. The standard error of prediction was 1.07%.
Immunosensors: technology and opportunities in laboratory medicine
Authors: Morgan C L , Newman D J , Price C P 
Published: January 2020

Abstract
An immunosensor is a device comprising an antigen or antibody species coupled to a signal transducer, which detects the binding of the complementary species. An indirect immunosensor uses a separate labeled species that is detected after binding by, e.g., fluorescence or luminescence (i.e., a heterogeneous immunoassay). A direct device detects the binding by a change in potential difference, current, resistance, mass, heat, or optical properties (i.e., a homogeneous immunoassay). Although indirect sensors may encounter fewer problems due to nonspecific binding effects, the direct sensors are capable of real-time monitoring of the antigen-antibody reaction. A wide range of molecules can be detected with detection limits ranging between 10(-9) and 10(-13) mol/L. However, there are only a few successful commercial applications of direct immunosensors, these being of the optical type. This review describes the principles underlying the technologies, their merits, limitations, and applications.
Urine sulfatides and the diagnosis of metachromatic leukodystrophy
Authors: Natowicz M R , Prence E M , Chaturvedi P , Newburg D S 
Published: January 2020

Abstract
A deficiency of the lysosomal enzyme arylsulfatase A (ASA) causes the lysosomal storage disorder metachromatic leukodystrophy (MLD). The diagnosis of MLD is straightforward in cases with deficient leukocyte or fibroblast ASA activity and a typical clinical history. However, several atypical and late-onset forms of MLD have been described. The diagnosis is also complicated by the high frequency of presumably benign polymorphisms at the ASA gene locus that are associated with markedly diminished in vitro ASA activity. Additional diagnostic tools are needed in the clinically and (or) enzymatically atypical cases. Although analyses of urinary sulfatides have been reported to be helpful in the diagnosis of MLD, previously described methods are complex and incompletely characterized and validated. We developed an improved method for determining urinary sulfatides and applied it to a cohort of individuals with MLD. The sulfatides are extracted from urine, separated from glycerol-based lipids by alkaline hydrolysis, isolated by ion-exchange chromatography, and hydrolyzed to galactosylceramide, which is then perbenzoylated and quantified by HPLC. This assay provides excellent resolution of sulfatides from other lipids and good analytical precision. In addition, the urinary sulfatide concentrations of healthy controls (mean +offSD: 0.16 +/- 0.07 nmol/mg creatinine; range: 0.07-0.34; n = 18) are clearly distinguished from those of individuals with MLD (7.6 +/- 6.1 nmol/mg creatine; 1.2-24.2; n = 20).
Ammonium persulfate: a safe alternative oxidizing reagent for measuring urinary iodine
Authors: Pino S , Fang S L , Braverman L E 
Published: January 2020

Abstract
The chloric acid method is most commonly used to obtain accurate and reproducible measurements of iodine and remove interfering substances. Unfortunately chloric acid is a potential hazard, requiring an explosion-proof hood, among other precautions. We have developed a simple, convenient, and economic method for measuring urinary iodine by using 1 mol/L ammonium persulfate, a nonexplosive, nonhazardous chemical, as the oxidizing reagent. The oxidation procedure can be completed in 30 min at a temperature of 91-95 degrees C. The iodine in the urine is then measured by a modification of the traditional colorimetric method of Sandell and Kolthoff. Urine samples (110) collected from a mixed population of healthy males and females, ranging in age from 6 to 79 years and living in the US, were analyzed for urine iodine content by two methods: the proposed ammonium persulfate method and the chloric acid method. The ammonium persulfate method has an intraassay CV of 9.1% at 0.42 +/- 0.04 micromol/L (mean +/- SD), 7.8% at 1.46 +/- 0.11 micromol/L, and 4.0% at 3.54 +/- 0.14 micromol/L. The interassay CV is 10.2% at 0.46 +/- 0.05 micromol/L, and 7.9% at 3.27 +/- 0.26 micromol/L. Recovery of iodine added to urine in vitro was 107%, 94%, and 97% for 0.42 micromol/L, 0.77 micromol/L and 3.64 micromol/L, respectively. The lower limit of detectability was 0.0034 microgram of iodine. Values for iodine in 110 urines measured by the reference chloric acid method ranged from 0.06 to 8.03 micromol/L and by the ammonium persulfate method from 0.05 to 7.4 micromol/L. The persulfate method (y) correlated extremely closely with the reference chloric acid method (x) by the Pearson correlation (y = 0.923x + 0.810 micromol/L, and r = 0.994, Sy/x = 1.841).