bluuebunny/crossref_metadata_2025_split huggingface dataset:
Prevalence of familial dysalbuminemic hyperthyroxinemia in serum samples received for thyroid testing
Authors: Arevalo G 
Published: January 2020

Abstract
The prevalence of familial dysalbuminemic hyperthyroxinemia (FDH), a condition sometimes mistaken for hyperthyroidism, has not been clearly established. I present a study of the prevalence of FDH in serum samples received for thyroid-function tests in a reference laboratory. A prospective study of 15,674 serum samples was carried out over 24 months, of which 13,232 cases were from women (84.42%) and 2442 were from men (15.58%). FDH was diagnosed in 26 cases, 22 in women and four in men. Therefore, the prevalence of FDH in the total number of samples from both sexes was 0.17%, 0.17% in women, and 0.16% in men, which is consistent with a dominant autosomal type of familial transmission. These findings demonstrate that cases of FDH occur frequently; therefore, every laboratory must be prepared to recognize them and thus avoid an incorrect diagnosis of the patient's thyroid function.
What can be achieved in an external quality-assessment scheme with a small number of participants: four years of experience with thyroid-related tests in Israel
Authors: Kahana L , Yechieli H 
Published: January 2020

Abstract
The Israel External Quality-Assessment scheme (EQAS) provided service from 1985 to 1989, primarily to laboratories in Israel. Participation was voluntary and confidential, and involved 30-35 laboratories performing thyroid-related function tests. Scheme design included 36 human serum specimens distributed to the participants at the beginning of each year. For 12 months, three specimens were analyzed each month and the results were reported to EQAS on pre-agreed dates. Monthly reports sent by EQAS to participants after analysis of the results included the overall consensus mean used as target value, between-laboratory agreement, individual laboratory bias, and recovery data. The overall consensus mean calculated as all-laboratory trimmed mean was validated by reproducibility and recovery studies. Samples with undetectable concentrations of thyrotropin (TSH), obtained from patients proven thyrotoxic, were used to validate measurement of very low TSH concentrations. During the scheme, liquid serum was found superior to lyophilized specimens for distribution to the participants. The scheme helped stimulate major improvements in between-laboratory agreement, especially for low TSH concentrations, with CVs decreasing from 180% in the first year to 20% in the fourth year. Each laboratory's performance also improved as judged by the median bias and variability of bias and by the considerable decrease in the number of laboratories with unacceptable performance for all tests. Method-related differences in performance were observed despite the small number of participants. Better methods, e.g., a radioimmunometric method for TSH, were detected and adopted by the participants, with concomitant improvement in performance. Transfer to analog procedures for free thyroxin, in addition to, but mostly instead of, thyroxin, was also documented, with no gain in analytical performance. Despite this being a small scheme, most of the goals achievable with a large scheme were realized.
Polymerase chain reaction and Q beta replicase amplification
Authors: Cahill P , Foster K , Mahan D E 
Published: January 2020

Abstract
The polymerase chain reaction (PCR) and Q beta replicase are two methods in which nucleic acid polymerases are used for amplification. Although these approaches share many similar problems concerning target contamination and probe specificity, they differ dramatically in their mechanisms of action and modes of application. The PCR method amplifies target sequences between two priming oligonucleotides and in essence amplifies a portion of the analyte. Q beta replicase, on the other hand, amplifies a specific template molecule hybridized to target sequences and therefore amplifies a signal component of the system. For this reason, Q beta replicase amplification has applications in areas other than for the detection of nucleic acid sequences. The requirements for application and the advantages of both PCR and Q beta replicase amplification are reviewed.
Multiple labeling and time-resolvable fluorophores
Authors: Diamandis E P 
Published: January 2020

Abstract
A new time-resolved fluorescence immunoassay system involving use of the europium chelate of 4,7-bis(chlorosulfophenyl)-1,10-phenanthroline-2,9-dicarboxylic acid as label is reviewed. This stable chelate by itself is not very fluorescent but, used in multiple labeling strategies, improves the achievable detection limits. By using multiple labeling, streptavidin tailing, and Eu3+ activation, one can create a very stable, easy-to-use reagent that is suitable for devising highly sensitive immunoassays and other biotechnological assays. This reagent, a streptavidin-based macromolecular complex, is able to detect approximately 300,000 molecules (approximately 0.5 amol) of alpha-fetoprotein in a model noncompetitive immunoassay.
Optical biosensor assay (OBA)
Authors: Tsay Y G , Lin C I , Lee J , Gustafson E K , Appelqvist R , Magginetti P , Norton R , Teng N , Charlton D 
Published: January 2020

Abstract
We describe a new biosensor immunoassay involving optical diffraction to detect clinically important analytes in human body fluids. A silicon wafer is used as a support for immobilization of antigen or antibody. The protein-coated surface is illuminated through a photo mask to create distinct periodic areas of active and inactive protein. When the surface is incubated with a positive sample, antigen-antibody binding occurs only on the active areas. Upon illumination with a light source such as a laser, the resulting biological diffraction grating diffracts the light. A negative sample does not result in diffraction because no antigen-antibody binding occurs to create the diffraction grating. The presence or absence of a diffraction signal differentiates between positive and negative samples, and the intensity of the signal provides a quantitative measure of the analyte concentration. The technique is demonstrated with a quantitative assay of choriogonadotropin in serum.
Elimination of matrix and spectral interferences in the measurement of lead and cadmium in urine and blood by electrothermal atomic absorption spectrometry with deuterium background correction
Authors: D'Haese P C , Lamberts L V , Liang L , Van de Vyver F L , De Broe M E 
Published: January 2020

Abstract
Direct measurement of lead and cadmium in blood and urine by electrothermal atomic absorption spectrometry with deuterium background correction (D2-AAS) is prone to severe matrix and spectral interferences. We overcame these effects by coating the L'vov platform with ammonium molybdate, reducing the atomization time, introducing a post-atomization cooling step, carefully selecting ashing and atomization temperatures, and using an appropriate procedure for matrix modification. To determine Pb and Cd in blood and urine, we used matrix-matched calibration curves. With the proposed procedure for sample preparation, both Pb and Cd in whole blood can be determined in the same diluted sample. Results obtained by D2-AAS correlate closely with those by Zeeman-corrected AAS. Detection limits (mean blank + 3 SDblank) for Pb in urine and blood were 4 micrograms/L. For cadmium, the detection limits were 0.4 and 0.1 micrograms/L for urine and blood analysis, respectively. Between-run CVs were less than 5.0%.
Application of Neural Networks to the Interpretation of Laboratory Data in Cancer Diagnosis
Authors: Astion Michael L , Wilding Peter 
Published: January 2020

Abstract
Neural networks are a relatively new method of multivariate analysis. The purpose of this study was to investigate the ability of neural networks to differentiate benign from malignant breast conditions on the basis of the pattern of nine variables: patient age, total cholesterol, high-density lipoprotein cholesterol, triglycerides, apolipoprotein A-I, apolipoprotein B, albumin, the tumor marker CA15-3, and the Fossel index (measurement of methylene and methyl line-widths in proton NMR spectra). The laboratory analyses were made with blood plasma or serum specimens. The neural network was "trained" with 57 patients: 23 patients with breast malignancies and 34 patients with benign breast conditions. A neural network with nine input neurons, 15 hidden neurons, and two output neurons correctly classified all 57 patients. The ability of the network to predict the diagnoses of patients that it had no encountered in training was tested with a separate group (cross-validation group) of 20 patients. The network correctly predicted the diagnoses for 80% of these patients. For comparison we analyzed the same sets of 57 training patients and 20 cross-validation patients by quadratic discriminant function analysis. The quadratic discriminant function, calculated from the same 57 patients used to train the neural network, correctly classified 84% of the 57 patients, and correctly diagnosed 75% of the 20 cross-validation patients. The results suggest that neural networks are a potentially useful multivariate method for optimizing the diagnostic utility of laboratory data.
Hydroxyl Radical-Induced Characteristic Chemiluminescent Spectra from Plasma of Hemodialysis Patients
Authors: Agatsuma Shinichi , Nagoshi Toshiyuki , Kobayashi Masaki , Usa Masashi , Watanabe Haruo , Sekino Hiroshi , Inaba Humio 
Published: January 2020

Abstract
Plasma from hemodialysis patients evoked weak photon emissions (chemiluminescence) in a characteristic emission spectrum with a peak at 430 nm, attributed to attack by hydroxyl radicals generated from the iron-catalyzed breakdown of hydrogen peroxide (Fenton reaction), whereas plasma from normal healthy subjects showed a rather weak red chemiluminescence peak at around 680 nm, similar to that resulting from attack by hydroxyl radicals. However, the addition of hydrogen peroxide in the absence of divalent irons induced almost the same red chemiluminescent emission spectrum in both plasmas. The HPLC-gel-filtration chromatography carried out with both plasmas revealed that a primary emitter evoking a peak emission at 430 nm was located in the fraction of lower-molecular-mass substances in fractionated plasma from hemodialysis patients. In contrast, the elution peaks evoking red chemiluminescence with the addition of hydrogen peroxide were mainly observed for the higher-molecular-mass fraction, as determined by gel chromatography of both plasmas. Therefore, the observation of a chemiluminescence peak at 430 nm, induced by the generation of hydroxyl radicals, correlated well with chemiluminescent emissions in plasma samples from patients with chronic renal failure. Spectral analyses of clinical samples that show weak chemiluminescence by forced oxidation by such an active oxygen may provide a new and more sensitive method for diagnosing metabolic disorders.
Development of Time-Resolved Immunofluorometric Assay of Vascular Permeability Factor
Authors: Yeo Kiang-Teck , Sioussat Tracy M , Faix James D , Senger Donald R , Yeo Tet-Kin 
Published: January 2020

Abstract
We describe a two-site time-resolved immunofluorometric assay for guinea pig vascular permeability factor (VPF) for quantifying VPF in different biological fluids. Antibody against the carboxy terminus (C-IgG) is immobilized on microtiter wells, and antibody against the amino terminus (N-IgG) is labeled with Eu(3+)-chelate. Line 10 tumor culture medium, known to be rich in VPF, is assayed in a two-step incubation. Bound Eu3+ is then quantified by dissociation into a fluorescent enhancement solution, with measurement of the time-resolved fluorescence. The analytical sensitivity is 0.35 VPF unit, and the intra-assay CV is about 20%. The assay is specific for VPF, because pre-treatment with the appropriate C- or N-peptide, or pre-extraction of VPF, greatly decreases fluorescence. The VPF immunoassay is highly correlated (r2 = 0.94) with the Miles permeability assay, the classical bioassay of VPF. In addition, the immunofluorometric assay is about 30-fold more sensitive than the Miles assay.
Direct, Simplified, and Sensitive Assay of Angiotensin II in Plasma Extracts Performed with a High-Affinity Monoclonal Antibody
Authors: Simon D , Romestand B , Huang H , Badouaille G , Fehrentz J A , Pau B , Marchand J , Corvol P 
Published: January 2020

Abstract
A very simple, fast, and sensitive RIA of angiotensin (Ang) II has been developed, based on a monoclonal antibody with high affinity and specificity, making possible the direct measurement of circulating Ang II in human plasma after solid-phase extraction. The purified monoclonal antibody 4D8 has an association constant of 1.3 x 10(11) L/mol with Ang II and a cross-reactivity of &lt; 1% for Ang I. The assay can detect as little as 0.8 fmol of Ang II in 2 mL of plasma and is not influenced by the presence of Ang I. Analytical recoveries between 112% and 116% were obtained for Ang II added to human plasma at physiological concentrations. Comparison of the RIA with a reversed-phase, high-performance liquid chromatographic method followed by RIA to measure Ang II in human plasma samples from normal and hypertensive subjects--and from normotensive subjects before and after an acute inhibition of angiotensin-converting enzyme with captopril (50 mg)--showed a high degree of correlation (r2 = 0.93) between the two methods.
Sensitive, Specific Radioimmunoassay for Quantifying Pergolide in Plasma
Authors: Bowsher R R , Apathy J M , Compton J A , Wolen R L , Carlson K H , DeSante K A 
Published: January 2020

Abstract
Pergolide, a synthetic ergoline with potent dopaminergic activity, is used to treat Parkinson disease. The low plasma concentrations of pergolide achieved during therapy complicate the development of a method for its analysis. Because radioimmunoassay successfully measures other structurally related ergolines in physiological fluids, we undertook the development of a radioimmunoassay of pergolide. The detection limit of the radioimmunoassay is 21 ng/L with an optimal working range from 100 to 1000 ng/L. We maximized assay specificity by using a monoclonal antibody that displayed low cross-reactivity with pergolide sulfoxide, a major metabolite found in animals. The radioimmunoassay has performed acceptably for &gt; 2 years during toxicology studies with rats and rhesus monkeys and in clinical studies involving patients with Parkinson disease. We consider the radioimmunoassay a valid method for quantifying therapeutic concentrations of pergolide in plasma.
Determination of Fetal Hemoglobin by Time-Resolved Immunofluorometric Assay
Authors: Turpeinen U , Stenman U H 
Published: January 2020

Abstract
We have developed a "sandwich"-type time-resolved immunofluorometric assay (IFMA) for fetal hemoglobin (HbF) in hemolysates from adults and newborns, amniotic fluid, and plasma, based on a polyclonal and a monoclonal antibody against human fetal hemoglobin. Microtiter wells are coated with polyclonal capture antibody, and the gamma-chain-specific monoclonal tracer antibody is labeled with a europium chelate. In a simple and fast assay procedure, prediluted hemolysates are incubated in the microtiter wells first with capture antibody for 1 h and, after washing, for 1 h with tracer antibody. The wells are washed and the fluorescence of europium is measured. The mean analytical recovery is 102% and results by IFMA agreed well with values obtained by high-performance liquid chromatography. The analytical range of IFMA is large and well suited for clinical purposes. The detection limit of the assay is 0.2 microgram/L and the measuring range extends to 500 micrograms/L.
Precipitation and Characterization of an Aluminosilicate from ALCL3-Na2SiO3-HCL in Serum, of Interest for Alzheimer Disease
Authors: Bilinski H , Horvath L , Trbojevic-Cepe M 
Published: January 2020

Abstract
A precipitation experiment was performed with human serum to model aluminosilicate formation in brains of patients with Alzheimer disease. Aluminum and (or) silicate ions were added to serum in a 1:2 molar ratio at pH 7.4. Precipitates formed immediately and were left for 24 h at 37 degrees C before filtration. Silicate and aluminosilicate formed precipitates with human serum proteins albumin, transferrin, and IgG. In untreated samples, the IgG/albumin ratio increased slightly compared with the ratio in dried serum. Diethylbarbiturate-washed precipitates had a significantly lower protein content than did untreated ones. The IgG/albumin ratio increased considerably in the sample containing aluminosilicate. We conclude that IgG is the sodium dodecyl sulfate-soluble human protein most firmly bound to the aluminosilicate matrix. From 27Al magic-angle-spinning nuclear magnetic resonance (MAS NMR), a pronounced peak was found at 52.79 ppm and a minor peak at 0.53 ppm, suggesting that 4-coordinated aluminum predominates and that 6-coordinated aluminum is present in a smaller proportion. The 29Si MAS NMR spectrum shows a poorly ordered structure. The aluminosilicate formed also contains the cations Na+ &gt; K+ &gt; Ca2+ &gt; Mg2+ and anions Cl- &gt; PO4(3-). Rather than looking for aluminum toxicity to explain the effects of Alzheimer disease, one should consider that by precipitating such a composite phase, the balance of cations, anions, and proteins in human serum is changing.
Specific Assay of Serum Lactate Dehydrogenase Isoenzyme 1 by Proteolysis with Alpha-Chymotrypsin and Protein Denaturation
Authors: Shirahase Y , Watazu Y , Kaneda N , Uji Y , Okabe H , Karmen A 
Published: January 2020

Abstract
We devised a method for assaying serum lactate dehydrogenase isoenzyme 1 (LD-1) activity specifically by preincubation with alpha-chymotrypsin and guanidine. Cleavage of phenylalanine bonds in the loop of A and B subunits of LD-3, LD-4, and LD-5 isoenzymes (residues 117-119) by incubation with alpha-chymotrypsin for a short time completely inactivated these isoenzymes and partially inactivated LD-2. Addition of guanidine (0.50 mol/L, pH 7.8) to the incubation mixture containing the chymotrypsin completed the inactivation of LD-2. As much as 4000 U/L of LD-2, LD-3, LD-4, and LD-5 were inactivated, whereas LD-1 was affected only slightly. Results by this method (y) correlated well with those by the Roche Isomune immunochemical LD-1 method (x): y = 0.98 x -0.11, r = 0.99 (n = 60). Within-run CVs were 0.5-2.5%. Several common interferents had no effect. In 500 healthy people, serum LD-1 ranged between 66 and 130 U/L, with a mean +/- SD of 88 +/- 15 U/L.
Cross-Reactivity of Anti-Digoxin Antibodies with Digitoxin Depends on Tracer Structure
Authors: Stenzel R , Reckmann B 
Published: January 2020

Abstract
The most common methods for measuring digoxin concentrations in serum are immunoassays. The prerequisite for exact determination of the digoxin value is an antibody that specifically binds digoxin. Because digitoxin differs from digoxin only in the C-12 hydroxy group, it is difficult to obtain anti-digoxin antibodies that do not cross-react with this compound. During the development of a fluorescence polarization immunoassay (FPIA) for digoxin, we investigated digoxin tracers with different structures. We found that in FPIA the digitoxin cross-reactivity of an antibody could be reduced by varying the structure of the tracer molecule.
Sandwich Immunoassay for Intact Human Osteocalcin
Authors: Hosoda K , Eguchi H , Nakamoto T , Kubota T , Honda H , Jindai S , Hasegawa R , Kiyoki M , Yamaji T , Shiraki M 
Published: January 2020

Abstract
To overcome the problems of limited-region specificity associated with conventional radioimmunoassay (RIA), we developed a sandwich enzyme immunoassay (EIA) for intact human osteocalcin (hOC). For this EIA we used antibodies to the N- and C-terminal regions of hOC that were raised against an N-terminal 20-residue peptide and a C-terminal 7-residue peptide, both synthetic. Immunoassay profiles of tryptic digests of hOC and serum from patients with renal failure, fractionated by reversed-phase HPLC, facilitated direct demonstration of the region specificity of this method. A preliminary study of serum osteocalcin concentrations in patients with renal failure further confirmed this specificity, showing lower positive rates obtained by this method than by conventional RIA. The cross-reactivity data of hOC with bovine and rat osteocalcins by the sandwich method indicated its species specificity. These studies demonstrate the superior specificity of this sandwich EIA compared with conventional RIA and thus confirm its potential diagnostic superiority.
Plasma Lipoprotein(a) Values and Severity of Coronary Artery Disease in a Large Population of Patients Undergoing Coronary Angiography
Authors: Labeur C , De Bacquer D , De Backer G , Vincke J , Muyldermans L , Vandekerckhove Y , Van der Stichele E , Rosseneu M 
Published: January 2020

Abstract
To determine possible associations between lipoprotein(a) [Lp(a)] and the severity of coronary artery lesions, we measured lipid, apolipoprotein, and Lp(a) in a large population of Belgian patients (n = 1054) undergoing coronary angiography. In both women and men, univariate analysis demonstrated significant differences in the Lp(a) concentrations according to the severity of the coronary stenosis. However, after adjustment for possible confounding factors, many of these differences were attenuated, indicating that other variables that differentiate patients from control subjects also influence Lp(a) distribution. Differences in lipid, apolipoprotein, and Lp(a) concentrations between male and female patients are discussed.
Analytical and Clinical Evaluation of Creatine Kinase MB Mass Assay by IMx: Comparison with MB Isoenzyme Activity and Serum Myoglobin for Early Diagnosis of Myocardial Infarction
Authors: Van Blerk M , Maes V , Huyghens L , Derde M P , Meert R , Gorus F K 
Published: January 2020

Abstract
We analytically and clinically evaluated Abbott's IMx assay for creatine kinase (CK) isoenzyme MB (CK-MB) in serum. Over a 1-year period, the method was more specific but less precise than catalytic isoenzyme measurements by electrophoresis or immunoinhibition. Sera from different individuals without electrophoretic evidence of CK-MB but containing macro CK type 1 (n = 20), mitochondrial CK (n = 5), or CK-BB (n = 5) were scored as CK-MB negative by the IMx. Likewise, CK-MB-negative by the sera remained so after addition of purified human CK-MM (&lt; or = 7600 U/L) or CK-BB (&lt; or = 8100 U/L). For 39 patients admitted for suspicion of uncomplicated acute myocardial infarction (precordial pain for &lt; or = 4 h), the diagnostic performance of the IMx CK-MB assay on admission and 4 h later was superior to that of total CK activity and compared well with that of CK-MB activity measured by electrophoresis or immunoinhibition. An admission, myoglobin showed a higher diagnostic sensitivity, specificity, and predictive value than did CK-MB and was the most informative test. Diagnostic performance on admission and 4 h later was further improved by considering positivity for myoglobin and for CK-MB by IMx and for the change in each over the first 4 h of hospitalization as criteria. Twelve hours after admission, diagnostic performance was further improved for all CK and CK-MB methods but began to decline for myoglobin.