bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cardiac troponin T in diagnosis of acute myocardial infarction
Authors: Mair Johannes , Artner-Dworzak Erika , Lechleitner Peter , Smidt Jörn , Wagner Ina , Dienstl Franz , Puschendorf Bernd 
Published: January 2020

Abstract
Troponin T is a structurally bound protein found in striated muscle cells. We tested concentrations of its cardiac-specific isotype in peripheral venous blood samples serially drawn from 72 patients with confirmed myocardial infarction. Fifty-nine patients received thrombolytic treatment with intravenous streptokinase, urokinase, or recombinant tissue-type plasminogen activator; because of contraindications, the remaining 13 patients did not. Concentrations of troponin T in plasma, measured by an enzyme-linked immunosorbent assay, started increasing within a few hours after the onset of symptoms (median, 4 h; range, 1-10 h). The sensitivity of troponin T for detecting myocardial infarction was 100% from 10 to 120 h after the onset of symptoms; sensitivity on the seventh day after admission was 84%. Concentrations were increased for up to three weeks in some patients with late or high peak values. Successful reperfusion in Q-wave infarction obviously influences the release of troponin T into plasma, with all such cases showing peak values less than or equal to 26 h (median, 14 h) after the onset of symptoms. Troponin T concentrations in these patients returned to within the reference interval more rapidly than in nonreperfused subjects. In the 13 patients without fibrinolytic therapy, troponin T tended to peak approximately 48 h (median) after the onset of chest pain. Troponin T concentrations in patients for whom thrombolysis was unsuccessful resembled those in patients without fibrinolytic therapy. The specificity of the assay was 96% as tested in samples of 96 emergency-room patients. The reference interval (less than 0.5 micrograms/L) was established from samples of 100 healthy blood donors. Troponin T measurements are a specific and sensitive method for the early and late diagnosis of acute myocardial infarction and could, therefore, provide a new criterion in laboratory diagnosis of its occurrence.
Ligand affinity chromatographic separation of serum IgG on recombinant protein G-silica
Authors: Cassulis Pauline , Magasic Mario V , DeBari Vincent A 
Published: January 2020

Abstract
We purified IgG by an automated chromatographic procedure, using a recombinant DNA-produced Protein G ligand bound to silica as the solid phase. The IgG can be separated from human serum in approximately 20 min with little operator manipulation. Recovery studies indicate that unconcentrated eluates contain 77-100% of the applied IgG. Concentration to volumes approximating that of the applied serum resulted in recovery of 76-98% of the applied IgG. High-resolution protein electrophoresis of the eluates demonstrated retention of the broad gamma band, with virtual absence of other serum proteins. This finding was confirmed by immunoelectrophoresis, which demonstrated homogeneity of IgG in the eluates. IgG subclass distributions in four eluates, compared with the sera from which they were harvested, indicate comparable percentages of IgG1, IgG2, and IgG3 and some enhancement of the IgG4 fraction [serum IgG4: 2.9 +/- 0.4% (SEM); eluate IgG4: 13.8 +/- 1.7%, P = 0.007]. The reactivity of eluates from two sera containing various antibodies to human immunodeficiency virus type 1 was virtually identical to that of the sera from which they were prepared. We conclude that this chromatographic application is an effective purification method for serum IgG and antibodies of the IgG class. The method may be applicable in the specialty clinical laboratory, particularly in those interested in protein and other immunological abnormalities.
Time-integrated measurement of corticosteroids in saliva by oral diffusion sink technology
Authors: Wade Stephen E , Haegele Albert D 
Published: January 2020

Abstract
Saliva, as a medium for assessing adrenocortical function in humans, has many advantages and a few distinct disadvantages. Interpretation of measurements of saliva cortisol is complicated by the contamination of saliva by steroid-binding proteins from blood plasma, enzyme activity in the salivary gland that converts cortisol to cortisone, and the amplification in saliva of the episodic fluctuations in systemic cortisol concentrations. We describe a new measurement technology that rejects artifacts from contamination of saliva by plasma protein, provides for measurement of both cortisol and cortisone, and integrates episodic fluctuations in concentration over a period of hours. This oral diffusion sink technology may greatly enhance the reliable interpretation of corticosteroid concentrations measured in saliva.
Isolation and characterization of zinc coproporphyrin I: a major fluorescent component in meconium
Authors: Horiuchi Kentaro , Adachi Kyoko , Fujise Yutaka , Naruse Hireo , Sumimoto Kazuhiro , Kanayama Naohiro , Terao Toshihiko 
Published: January 2020

Abstract
We isolated a substance from an organic extract of meconium (in neutral pH) that exhibited a porphyrin-like fluorescence peak at 580 nm on excitation at 405 nm and deduced its structure. Spectrometric data suggest that the substance is not free coproporphyrin I or free coproporphyrin III, but is a chelate of coproporphyrin I with Zn2+. We also detected a chelate of coproporphyrin III with Zn2+ by HPLC. These substances may be useful as new indicators of the presence of meconium.
Rapid and specific enzyme immunoassay of serotonin
Authors: Chauveau J , Fert V , Morel A M , Delaage M A 
Published: January 2020

Abstract
A new, highly sensitive enzyme immunoassay (EIA) of serotonin (5HT) is described. The assay is based on the competition between N-succinyl-glycinamide-serotonin (N-SGA-5HT, obtained by acylation of the 5HT in the sample to be assayed) and an enzymic tracer, N-succinyl-5HT-acetylcholinesterase, for binding to rabbit polyclonal antibody coated onto the wells of microtiter plates. The antibody is directed against an immunogen obtained by coupling N-succinyl-5HT to glycyl-bovine serum albumin. The EIA permits the accurate measurement of as little serotonin as 0.5 nmol/L (1.8 pg per well) in blood, plasma, serum, cerebrospinal fluid, urine, platelets, and other tissues, with no significant cross-reactivity with other compounds. The results obtained correlate well with those obtained by HPLC after extraction. The assay has the advantage of permitting the measurement of 5HT in up to 500 samples in as little as 3 h.
Combi scheme: new combined internal/external quality-assessment scheme in The Netherlands
Authors: Steigstra Herman , Jansen Rob T , Baadenhuijsen Henk 
Published: January 2020

Abstract
The Dutch Foundation for Quality Assessment in Clinical Chemistry (SKZL) is the professional organization that conducts external quality-assessment schemes in The Netherlands. However, such schemes in fact assess the performance of the internal quality-control systems of the participating laboratories. In this paper we describe a new concept, relating the data for internal control materials with those for external samples and thereby leading to a combined external/internal scheme (Combi). The statistical principles underlying the Combi scheme are discussed and examples of the graphical presentation of the results are shown. Because the laboratory data are transmitted over the public telephone system to the computers of the SKZL, we also describe the principles of the data communication. At two-month intervals a statistical presentation is sent to all participants. The central database is updated daily with the received results, making possible an on-line consultation regarding the statistics of the accumulated findings of the control materials in use.
Aluminum phthalocyanine-streptavidin: new, sensitive fluorescent tracer for immunoassay
Authors: Kelly T A , Hunter C A , Schindele D C , Pepich B V 
Published: January 2020

Abstract
A new fluorescent reagent based on aluminum phthalocyanine has been developed for general application to immunoassay. This highly sensitive fluorophore, Ultralite 680, may be covalently attached to a variety of biological entities for use as a tracer. We report the use of an Ultralite 680-streptavidin-digoxin conjugate as a tracer in a direct, competitive, heterogeneous, fluorescent immunoassay of digoxin. The assay is performed manually with 50 microL of serum and no sample pre-treatment. Primary anti-digoxin antibody is incubated with a serum sample containing digoxin and Ultralite 680-streptavidin-digoxin. Bound and free tracer are separated, and the bound fluorescence is released and quantified with a commercially available spectrofluorometer. Assay precision was good (CV = 7.05% at a digoxin concentration of 2.00 micrograms/L) and results by our method correlated well with those by a conventional RIA (r = 0.9650, n = 24).
Monoclonal and oligoclonal gammopathies in heart-transplant recipients
Authors: Myara I , Quenum G , Storogenko M , Tenenhaus D , Guillemain R , Moatti N 
Published: January 2020

Abstract
Immunoglobulin abnormalities in serum from 76 heart-transplant recipients were examined by cellulose acetate and agarose gel electrophoresis. Monoclonal components were typed by immunofixation. IgG, IgA, and IgM and total kappa and lambda light chains were quantified by immunonephelometry. We confirm that both monoclonal and oligoclonal immunoglobulin banding are common in serum from these patients. Of the 149 serum samples examined, 21 (15%) had one monoclonal component and 53 (35%) had two or more. These monoclonal immunoglobulins were generally present at a low concentration and were transient. The class of immunoglobulins most commonly involved was IgG (about sevenfold more numerous than IgM); monoclonal IgA components and free light chains were not detected. The nephelometric kappa/lambda and heavy chain/light chain ratios were poor indicators of these abnormalities. Immunoglobulin abnormalities were not correlated with the sex and age of recipients, the pre-existing cardiopathy, the time since transplantation, or plasma concentrations of cyclosporine, but did correlate with plasma immunoglobulin concentration, biopsy findings, and viral infections, especially cytomegalovirus (CMV). A monoclonal IgG purified from a patient with a high titer of anti-CMV antibodies did not react with CMV antigens. The origin of these immunoglobulin abnormalities is unclear. Our data suggest that the presence of monoclonal or oligoclonal banding in heart-transplant recipients is of limited prognostic significance.
Cancer antigen 125 in serum and ascitic fluid of patients with liver diseases
Authors: Molina R , Filella X , Bruix J , Mengual P , Bosch J , Calvet X , Jo J , Ballesta A M 
Published: January 2020

Abstract
Serum concentrations of cancer antigen 125 (CA 125) were determined for 373 patients with various liver diseases: 57 with acute hepatitis, 57 with chronic hepatitis, 244 with liver cirrhosis (86 compensated and 158 decompensated), and 15 with primary liver cancer. The antigen was measured simultaneously in the serum and ascitic fluid of 46 of the patients with liver cirrhosis and sequentially in the serum and ascitic fluid of another 25 cirrhotics treated with paracentesis and (or) diuretics. Abnormal results for CA 125 were detected in sera from 4% of the patients with acute or chronic hepatitis, 60% of the patients with liver cirrhosis, and 67% of the patients with primary liver cancer. The main factor associated with abnormal serum concentrations of this antigen was the presence of ascites, with pathological CA 125 values in 94% of patients with ascites without jaundice (mean 566 +/- 528 arb. units/mL), compared with only 40% of patients with jaundice and without ascites (mean 40.1 +/- 28.5 arb. units/mL) (P less than 0.001). High concentrations of CA 125 were mainly associated with spontaneous bacterial peritonitis. The serum concentration of CA 125 decreased after treatment with paracentesis, but increased in patients treated with diuretics rather than paracentesis. The release of this antigen in liver cirrhosis appears to be independent of the liver disorder and, rather, results from peritoneal synthesis of this antigen.
Free and bound malondialdehyde measured as thiobarbituric acid adduct by HPLC in serum and plasma
Authors: Carbonneau M A , Peuchant E , Sess D , Canioni P , Clerc M 
Published: January 2020

Abstract
Assay of free and total malondialdehyde (MDA) in human serum and plasma from healthy subjects and from patients with high risk of lipoperoxidation was performed as follows: (a) acidic (HClO4, pH 1, at 20 degrees C) or basic (NaOH, pH 13, at 60 degrees C) treatments for 30 min; (b) reaction of the protein-free extract (obtained by acid precipitation) with thiobarbituric acid (TBA); (c) HPLC separation on C18 columns with an eluting solution of methanol/phosphate buffer, 10 mmol/L, pH 5.8 (40/60, by vol), at a flow rate of 1.5 mL/min. Free MDA averaged 0.042 (SEM 0.008) and 0.043 (SEM 0.007) mumol/L, respectively, in serum and plasma from healthy subjects. Free (+/- SEM) MDA increased significantly in the plasma from cancer patients (0.270 +/- 0.047 mumol/L) and from hemodialyzed patients (0.214 +/- 0.035 mumol/L). In serum of hemodialyzed patients, analyses for total MDA were unsuitable because of interfering peaks. MDA bound to NH2 groups constituted 83.2% and 83.5% of total MDA in serum and plasma of healthy subjects, respectively, and only 58% in plasma of hemodialyzed patients.
High-sensitivity laser-induced fluorescence detection for capillary electrophoresis
Authors: Zhang J Z , Chen D Y , Wu S , Harke H R , Dovichi N J 
Published: January 2020

Abstract
Capillary electrophoresis provides very high efficiency separations of biological molecules. Laser-induced fluorescence produces very high sensitivity detection. The combination of the two techniques results in an analytical tool with unprecedented properties: separations with more than a million theoretical plates and detection limits of a few hundred analyte molecules. This paper considers the design of high-sensitivity laser-induced fluorescence detection for capillary zone electrophoresis separation of labeled amino acids and capillary gel electrophoresis separation of DNA sequencing fragments.
Atomic force microscopy: seeing molecules of lipid and immunoglobulin
Authors: Hansma H G , Weisenhorn A L , Edmundson A B , Gaub H E , Hansma P K 
Published: January 2020

Abstract
The atomic force microscope (AFM) can image individual molecules by raster-scanning a sharp tip over a surface. In this paper we present molecular-resolution images of immunoglobulin M (IgM) and of ultraviolet light-polymerized films of the lipid dimethyl-bis(pentacosadiynoyloxyethyl) ammonium bromide ("BRONCO"). The polar head groups of individual lipid molecules can be resolved on the surface of this and other lipid films. These lipid films also provide a good substrate for AFM imaging of DNA and of other molecules such as antibodies. Because the AFM scans surfaces, it is most often successful at imaging either molecules that can form an array on a surface or molecules that are quite firmly attached to a surface. The ability of the AFM to operate under water, buffers, and other liquids makes it possible to study biological molecules under conditions in which they are physiologically active. Imaging of the actual molecular process of fibrin polymerization shows the potential of the AFM for studying biological processes. In the six years since its invention, the AFM has excited much interest and has imaged molecules in a wide range of systems.
Electrochemiluminescence detection for development of immunoassays and DNA probe assays for clinical diagnostics
Authors: Blackburn G F , Shah H P , Kenten J H , Leland J , Kamin R A , Link J , Peterman J , Powell M J , Shah A , Talley D B 
Published: January 2020

Abstract
Electrochemiluminescence (ECL) has been developed as a highly sensitive process in which reactive species are generated from stable precursors (i.e., the ECL-active label) at the surface of an electrode. This new technology has many distinct advantages over other detection systems: no radioisotopes are used; detection limits for label are extremely low (200 fmol/L); the dynamic range for label quantification extends over six orders of magnitude; the labels are extremely stable compared with those of most other chemiluminescent systems; the labels, small molecules (approximately 1000 Da), can be used to label haptens or large molecules, and multiple labels can be coupled to proteins or oligonucleotides without affecting immunoreactivity, solubility, or ability to hybridize; because the chemiluminescence is initiated electrochemically, selectivity of bound and unbound fractions can be based on the ability of labeled species to access the electrode surface, so that both separation and nonseparation assays can be set up; and measurement is simple and rapid, requiring only a few seconds. We illustrate ECL in nonseparation immunoassays for digoxin and thyrotropin and in separation immunoassays for carcinoembryonic antigen and alpha-fetoprotein. The application of ECL for detection of polymerase chain reaction products is described and exemplified by quantifying the HIV1 gag gene.
Abbott prism: a multichannel heterogeneous chemiluminescence immunoassay analyzer
Authors: Khalil O S , Zurek T F , Tryba J , Hanna C F , Hollar R , Pepe C , Genger K , Brentz C , Murphy B , Abunimeh N 
Published: January 2020

Abstract
We describe a multichannel heterogeneous immunoassay analyzer in which a sample is split between disposable reaction trays in a group of linear tracks. The system's pipettor uses noninvasive sensing of the sample volume and disposable pipet tips. Each assay track has (a) a conveyor belt for moving reaction trays to predetermined functional stations, (b) temperature-controlled tunnels, (c) noncontact transfer of the reaction mixture between incubation and detection wells, and (d) single-photon counting to detect a chemiluminescence (CL) signal from the captured immunochemical product. A novel disposable reaction tray, with separate reaction and detection wells and self-contained fluid removal, is used in conjunction with the transfer device on the track to produce a carryover-free system. The linear immunoassay track has nine predetermined positions for performing individual assay steps. Assay step sequence and timing is selected by changing the location of the assay modules between these predetermined positions. The assay methodology, a combination of microparticle capture and direct detection of a CL signal on a porous matrix, offers excellent sensitivity, specificity, and ease of automation. Immunoassay configurations have been tested for hepatitis B surface antigen and for antibodies to hepatitis B core antigen, hepatitis C virus, human immunodeficiency virus I and II, and human T-cell leukemia virus I and II.
Total arsenic in urine: palladium-persulfate vs nickel as a matrix modifier for graphite furnace atomic absorption spectrophotometry
Authors: Nixon D E , Mussmann G V , Eckdahl S J , Moyer T P 
Published: January 2020

Abstract
We evaluated the effectiveness of nickel and palladium with or without added potassium persulfate as matrix modifiers for the determination of total arsenic in urine. Complete recovery of pure aqueous solutions of As(III), As(V), cacodylic acid (DMA), monomethylarsinic acid (MMA), and o-arsanilic acid was attained by using both nickel and palladium modifiers. Combined arsenobetaine and arsenocholine (so-called fish arsenic), extracted from a certified control material of dogfish muscle (DORM-1), were completely recovered with Pd-S2O8 matrix modification, but not with nickel. Excellent agreement with target values for arsenic in urines from the Centre de Toxicologie du Quebec, supplied by the Interlaboratory Comparison Program, was attained irrespective of the arsenic source when we used Pd-S2O8 as the matrix modifier.
Prostate-specific antigen in serum occurs predominantly in complex with alpha 1-antichymotrypsin
Authors: Lilja H , Christensson A , Dahlén U , Matikainen M T , Nilsson O , Pettersson K , Lövgren T 
Published: January 2020

Abstract
Immunologic measurements of the serum concentration of prostate-specific antigen (PSA), an abundant prostatic-secreted serine proteinase, are frequently used to monitor patients with prostate cancer, though it has not been ascertained whether this immunoreactivity represents a PSA zymogen, the active proteinase, or PSA complexed to extracellular proteinase inhibitors. To characterize the PSA immunoreactivity in serum, we used monoclonal antibodies produced against PSA and a polyclonal rabbit IgG against alpha 1-antichymotrypsin in the design of three noncompetitive PSA assays: assay T, which detected PSA both when present as the active proteinase and when complexed to alpha 1-antichymotrypsin; assay F, which recognized the active proteinase but most poorly detected PSA complexed to alpha 1-antichymotrypsin; and assay C, which was specific for PSA complexed to alpha 1-antichymotrypsin. We used the three assays to measure PSA immunoreactivity in 64 patients' sera and in the effluent after gel chromatography of sera from four patients. This identified an 80- to 90-kDa complex between PSA and alpha 1-antichymotrypsin as the predominant fraction of the PSA immunoreactivity in blood plasma; an immunoreactive 25- to 40-kDa compound was the minor fraction.
Rapid electrochemiluminescence assays of polymerase chain reaction products
Authors: Kenten J H , Casadei J , Link J , Lupold S , Willey J , Powell M , Rees A , Massey R 
Published: January 2020

Abstract
We demonstrate the first use of an electrochemiluminescent (ECL) label, [4-(N-succimidyloxycarbonylpropyl)-4'-methyl-2,2'- bipyridine]ruthenium(II) dihexafluorophosphate (Origen label; IGEN Inc.), in DNA probe assays. This label allows rapid (less than 25 min) quantification and detection of polymerase chain reaction (PCR)-amplified products from oncogenes, viruses, and cloned genes. For the PCR, we used labeled oligonucleotide primers complementary to human papiloma virus and the Ha-ras oncogene. These samples were followed by ECL analysis or hybridization with specific, Origen-labeled oligonucleotide probes. These studies demonstrate the speed, specificity, and effectiveness of the new ECL labels, compared with 32P, for nucleic acid probe applications. We describe formats involving conventional methodologies and a new format that requires no wash step, allowing simple and rapid sample analysis. These rapid assays also reduce PCR contamination, by requiring less sample handling. Improvements in ECL detectability are currently under investigation for use in DNA probe assays without amplification.
Absorption spectra of human fetal and adult oxyhemoglobin, de-oxyhemoglobin, carboxyhemoglobin, and methemoglobin
Authors: Zijlstra W G , Buursma A , Meeuwsen-van der Roest W P 
Published: January 2020

Abstract
We determined the millimolar absorptivities of the four clinically relevant derivatives of fetal and adult human hemoglobin in the visible and near-infrared spectral range (450-1000 nm). As expected, spectral absorption curves of similar shape were found, but the small differences between fetal and adult hemoglobin absorptivity were important enough that they should be taken into account in multicomponent analysis of hemoglobin derivatives. Common pulse oximeters, however, involving light of 660 and 940 nm, are so insensitive to the presence of fetal hemoglobin that they can be used safely in neonates. The error in pulse oximetry caused by the presence of carboxyhemoglobin is insubstantial, but methemoglobin gives either an understimation or an overestimation at high or low oxygen saturation, respectively, the turning point being near 70% saturation.