bluuebunny/crossref_metadata_2025_split huggingface dataset:
Utility of Commonly Used Commercial Human Chorionic Gonadotropin Immunoassays in the Diagnosis and Management of Trophoblastic Diseases
Authors: Cole Laurence A , Shahabi Shohreh , Butler Stephen A , Mitchell Hugh , Newlands Edward S , Behrman Harold R , Verrill Harland L 
Published: January 2020

Abstract
Background: Patients with trophoblastic diseases produce ordinary and irregular forms of human chorionic gonadotropin (hCG; e.g., nicked hCG, hCG missing the β-subunit C-terminal segment, hyperglycosylated hCG, and free β subunit) that are recognized to differing extents by automated immunometric hCG (or hCGβ) assays. This has led to low or false-negative results and misdiagnosis of persistent disease. False-positive hCG immunoreactivity has also been detected, leading to needless therapy for trophoblastic diseases. Here we compare seven commonly used hCG assays.
Methods: Standards for five irregular forms hCG produced in trophoblastic diseases, serum samples from 59 patients with confirmed trophoblastic diseases, and serum samples from 12 women with previous false-positive hCG results (primarily in the Abbott AxSYM assay) were blindly tested by commercial laboratories in the Beckman Access hCGβ, the Abbott AxSYM hCGβ, the Chiron ACS:180 hCGβ, the Baxter Stratus hCG test, the DPC Immulite hCG test, the Serono MAIAclone hCGβ tests, and in the hCGβ RIA.
Results: Only the RIA and the DPC appropriately detected the five irregular hCG standards. Only the Beckman, DPC, and Abbott assays gave results similar to the RIA in the patients with confirmed trophoblastic diseases (values within 25% of RIA in 49, 49, and 54 of 59 patients, respectively). For samples that were previously found to produce false-positive hCG results, no false-positive results were detected with the DPC and Chiron tests (5 samples, median &lt;2 IU/L), but up to one-third of samples were false positive (&gt;10 IU/L) in the Beckman (1 of 5), Serono (2 of 9), and Baxter assays (1 of 5), and the hCGβ RIA (3 of 9; median for all assays, &lt;5 IU/L). These samples, which produced false-positive results earlier in the Abbott AxSYM assay, continued to produce high values upon reassessment (median, 81 IU/L).
Conclusions: Of six frequently used hCG immunometric assays, only the DPC detected the five irregular forms of βhCG, agreed with the RIA, and avoided false-positive results in the samples tested. This assay, and similarly designed assays not tested here, seem appropriate for hCG testing in the diagnosis and management of trophoblastic diseases.
Evaluation of Nine Automated High-Sensitivity C-Reactive Protein Methods: Implications for Clinical and Epidemiological Applications. Part 2
Authors: Roberts William L , Moulton Linda , Law Terence C , Farrow Genesis , Cooper-Anderson Margaret , Savory John , Rifai Nader 
Published: January 2020

AbstractBackground: C-Reactive protein (CRP) can provide prognostic information about risk of future coronary events in apparently healthy subjects. This application requires higher sensitivity assays than have traditionally been available in the clinical laboratory.Methods: Nine high-sensitivity CRP (hs-CRP) methods from Dade Behring, Daiichi, Denka Seiken, Diagnostic Products Corporation, Iatron, Kamiya, Olympus, Roche, and Wako were evaluated for limit of detection, linearity, precision, prozone effect, and comparability with samples from 388 apparently healthy individuals.Results: All methods had limits of detection that were lower than the manufacturers’ claimed limit of quantification except for the Kamiya, Roche, and Wako methods. All methods were linear at 0.3–10 mg/L. The Diagnostic Products Corporation, Kamiya, Olympus, and Wako methods had imprecision (CVs) &gt;10% at 0.15 mg/L. The Iatron, Olympus, and Wako methods demonstrated prozone effects at hs-CRP concentrations of 12, 206, and 117 mg/L, respectively. hs-CRP concentrations demarcating each quartile in a healthy population were method-dependent. Ninety-two to 95% of subjects were classified into the same quartile of hs-CRP established by the Dade Behring method by the Denka Seiken, Diagnostic Products Corporation, Iatron, and Wako methods. In contrast, 68–77% of subjects were classified into the same quartile by the Daiichi, Kamiya, Olympus, and Roche methods. No subject varied by more than one quartile by any method.Conclusions: Four of the nine examined hs-CRP methods classified apparently healthy subjects into quartiles of hs-CRP similar to the classifications assigned by the comparison method. Additional standardization efforts are required because an individual patient’s results will be interpreted using population-based cutpoints.
Characteristics of an Albumin Cobalt Binding Test for Assessment of Acute Coronary Syndrome Patients: A Multicenter Study
Authors: Christenson Robert H , Duh Show Hong , Sanhai Wendy R , Wu Alan H B , Holtman Verena , Painter Pennell , Branham Elizabeth , Apple Fred S , Murakami MaryAnn , Morris Deborah L 
Published: January 2020

AbstractBackground: The ability of the N-terminal region of human albumin to bind cobalt is diminished by myocardial ischemia. The characteristics of an assay based on albumin cobalt binding were assessed in suspected acute coronary syndrome patients and in a control reference population. The ability of the Albumin Cobalt Binding (ACBTM) Test measurement at presentation to predict troponin-positive or -negative results 6–24 h later was also examined.Methods: We enrolled 256 acute coronary syndrome patients at four medical centers. Blood specimens were collected at presentation and then 6–24 h later. The dichotomous decision limit and performance characteristics of the ACB Test for predicting troponin-positive or -negative status 6 h-24 h later were determined using ROC curve analysis. Results for 32 patients could not be used because the time of onset of ischemia appeared to have been &gt;3 h before presentation or was uncertain. The reference interval was determined by parametric analysis to estimate the upper 95th percentile of a reference population (n = 109) of ostensibly healthy individuals.Results: Increased cTnI was found in 35 of 224 patients. The ROC curve area for the ACB Test was 0.78 [95% confidence interval (CI), 0.70–0.86]. At the optimum decision point of 75 units/mL, the sensitivity and specificity of the ACB Test were 83% (95% CI, 66–93%) and 69% (95% CI, 62–76%). The negative predictive value was 96% (95% CI, 91–98%), and the positive predictive value was 33% (95% CI, 24–44%). The within-run CV of the ACB Test was 7.3%. Results for the reference population were normally distributed; the one-sided parametric 95th percentile was 80.2 units/mL.Conclusions: This exploratory study suggests that the ACB Test has high negative predictive value and sensitivity in the presentation sample for predicting troponin-negative or -positive results 6–24 h later.
Real-Time Quantitative Telomeric Repeat Amplification Protocol Assay for the Detection of Telomerase Activity2
Authors: Hou Mi , Xu Dawei , Björkholm Magnus , Gruber Astrid 
Published: January 2020

AbstractBackground: Telomerase is a ribonucleoprotein enzyme associated with immortalization and transformation of human cells. The telomeric repeat amplification protocol (TRAP) is widely used for the detection of telomerase activity. The TRAP method, although highly sensitive and specific because it includes PCR amplification, is laborious and does not provide precise quantitative information.Methods: We developed a real-time quantitative TRAP (RTQ-TRAP) system by combining a real-time PCR technique with the conventional TRAP method. Telomerase activity in human tumor cell lines and in 13 lymphoma samples was measured using the RTQ-TRAP assay, and the results obtained from the samples using the RTQ-TRAP method were compared with the conventional TRAP method.Results: The RTQ-TRAP method was both accurate and reproducible in measuring telomerase activity in a dilution series of protein extracts from HL60 cells. Telomerase activity in 13 lymphoma samples, as determined by the RTQ-TRAP method, was ninefold lower than that measured by the conventional TRAP method. The half-life of telomerase activity in human tumor cells, as determined using RTQ-TRAP, was much shorter than the half-life reported previously.Conclusions: Our results suggest that the conventional TRAP assay frequently overestimates telomerase activity in tumor samples. The RTQ-TRAP method is thus a useful tool to rapidly and precisely quantify telomerase activity.
Homogeneous Enzyme Immunoassay for Triiodothyronine in Serum
Authors: Karapitta Christina D , Sotiroudis Theodore G , Papadimitriou Athanassios , Xenakis Aristotelis 
Published: January 2020

AbstractBackground: The concentration of triiodothyronine (T3) in human serum is extremely low and can be determined only by very sensitive methods. We developed a homogeneous enzyme immunoassay for T3 analysis in unextracted serum.Methods: A T3 derivative was conjugated to the −SH groups of glycogen phosphorylase b (GPb) from rabbit muscle. Conjugation caused inhibition of enzyme activity, and the enzyme conjugate was reactivated upon binding of anti-T3 antibody. Activation was blocked by the presence of non-antibody-bound T3; this was the basis for the development of the homogeneous enzyme immunoassay for T3 by determining GPb activity fluorometrically.Results: We used furosemide to block the interaction of T3 with serum proteins with T3-binding sites, avoiding any serum treatment step. T3 was measured in the range 0.3–8 μg/L. T3 values obtained by this assay correlated well with those obtained by a RIA (y = 0.97x − 0.07 μg/L; r = 0.96; n = 92). Within- and between-run imprecision (CV) was 5–9% for normal and high concentrations and 16–20% for low concentrations.Conclusions: Chemical modification of GPb with a T3 derivative allows the development of a simple homogeneous enzyme immunoassay for T3 in unextracted serum.
C677T and A1298C Polymorphisms of the Methylenetetrahydrofolate Reductase Gene: Incidence and Effect of Combined Genotypes on Plasma Fasting and Post-Methionine Load Homocysteine in Vascular Disease
Authors: Hanson Naomi Q , Aras Ömer , Yang Feng , Tsai Michael Y 
Published: January 2020

Abstract
Background: Moderately increased plasma concentrations of total homocysteine (tHcy) have been shown to be an important risk factor for vascular diseases. Two common polymorphisms of the methylenetetrahydrofolate reductase (MTHFR) gene, the thermolabile C677T and a more recently reported A1298C polymorphism, may contribute to hyperhomocysteinemia.
Methods: Using PCR and restriction fragment length polymorphism analysis, we studied the prevalence of the C677T and A1298C MTHFR genotypes and the combined effect of these polymorphisms on plasma tHcy concentrations, as measured by HPLC with fluorometric detection, both fasting and post-methionine load (PML), in 1238 individuals.
Results: The prevalences of the C677T and A1298C genotypes did not differ significantly in 772 individuals with documented coronary artery disease (CAD), 137 individuals with deep-vein thrombosis (DVT), and 329 individuals without documented vascular disease. Individuals homozygous for the 677T allele had significantly increased fasting tHcy, particularly in the presence of low folate, compared with individuals homozygous for the wild-type allele. Neither the 1298AC nor the 1298CC genotype was associated with significantly increased fasting or PML tHcy concentrations irrespective of serum folate. Of the nine combined MTHFR genotypes, six were present in &gt;10% of the population. Of these, the difference in mean fasting tHcy reached statistical significance (P &lt;0.005) only in individuals with the 677TT/1298AA genotype compared with individuals with the wild-type 677CC/1298AA genotype. Differences in mean fasting tHcy did not reach statistical significance in individuals heterozygous for both MTHFR variants. We detected two 677CT/1298CC and three 677TT/1298AC individuals; only one, an 677TT/1298AC individual, had increased tHcy (both fasting and PML). No individuals had the 677TT/1298CC genotype.
Conclusions: The prevalences of the C677T and A1298C polymorphisms did not differ among individuals with CAD, DVT, or those without documented vascular disease. In contrast to the C677T polymorphism, the A1298C polymorphism is not associated with increased fasting tHcy. Although the two polymorphisms usually exist in trans configuration, crossover may occur rarely to form recombinant chromosomes.
Determination of RhD Zygosity: Comparison of a Double Amplification Refractory Mutation System Approach and a Multiplex Real-Time Quantitative PCR Approach
Authors: Chiu Rossa W K , Murphy Michael F , Fidler Carrie , Zee Benny C Y , Wainscoat James S , Lo Y M Dennis 
Published: January 2020

Abstract
Background: Rh isoimmunization and hemolytic disease of the newborn still occur despite the availability of Rh immunoglobulin. For the prenatal investigation of sensitized RhD-negative pregnant women, determination of the zygosity of the RhD-positive father has important implications. The currently available molecular methods for RhD zygosity assessment, in general, are technically demanding and labor-intensive. Therefore, at present, rhesus genotype assessment is most commonly inferred from results of serological tests. The recent elucidation of the genetic structure of the prevalent RHD deletion in Caucasians, as well as the development of real-time PCR, allowed us to explore two new approaches for the molecular determination of RhD zygosity.
Methods: Two methods for RhD zygosity determination were developed. The first was based on the double Amplification Refractory Mutation System (double ARMS). The second was based on multiplex real-time quantitative PCR. For the double ARMS assay, allele-specific primers were designed to directly amplify the most prevalent RHD deletion found in RhD-negative individuals in the Caucasian population. The multiplex real-time quantitative PCR assay, on the other hand, involved coamplification and quantification of RHD-specific sequences in relation to a reference gene, albumin, in a single PCR reaction. A ratio, ΔCt, based on the threshold cycle, was then determined and reflects the RHD gene dosage.
Results: The allele-specific primers of the double ARMS assay reliably amplified the RHD-deleted allele and therefore accurately distinguished homozygous from heterozygous RhD-positive samples. The results were in complete concordance with serological testing. For the multiplex real-time quantitative PCR assay, the ΔCt values clearly segregated into two distinct populations according to the RHD gene dosage, with mean values of 1.70 (SD, 0.17) and 2.62 (SD, 0.29) for the homozygous and heterozygous samples, respectively (P &lt;0.001, t-test). The results were in complete concordance with the results of serological testing as well as with the double ARMS assay.
Conclusion: Double ARMS and real-time quantitative PCR are alternative robust assays for the determination of RhD zygosity.
Evaluation of a Fully Automated Serum Assay for C-Terminal Cross-Linking Telopeptide of Type I Collagen in Osteoporosis
Authors: Garnero Patrick , Borel Olivier , Delmas Pierre D 
Published: January 2020

Abstract
Background: Biochemical markers of bone turnover can provide prognostic information about the risk of osteoporotic fracture and are useful tools for monitoring efficacy of antiresorptive therapy. A serum-based automated assay may be of better clinical value than urinary markers because of lower imprecision and day-to-day within-person variability. Our aim was to evaluate the technical and clinical performances of a new, fully automated assay for serum C-terminal cross-linking telopeptide of type I collagen (CTX), a marker of bone resorption.
Methods: Serum CTX was measured on the Elecsys 2010 automated analyzer (Roche). Results were compared with those of the manual ELISA. We measured serum CTX concentrations in 728 healthy women, ages 31–89 years. We investigated the ability of this assay to predict the rate of postmenopausal forearm bone loss evaluated by four repeated bone mineral density measurements using dual-x-ray absorptiometry in 305 women followed prospectively for 4 years. Finally, in a cohort of healthy, untreated, postmenopausal women, we compared baseline serum CTX in 55 women who subsequently had a fracture (20 vertebral and 35 peripheral fractures) with values in the 380 women who did not fracture during a mean 5 years of follow-up.
Results: The within- (n = 21) and between-run (n = 21) CVs were &lt;4.1% and 5.7%, respectively. In 728 healthy women, serum CTX concentrations (automated) correlated with those of the manual ELISA (r = 0.82; P &lt;0.0001). The median long-term within-person variability assessed by four repeated measurements over 3 months in 18 postmenopausal women was 9.4%. Compared with 254 premenopausal women, serum CTX was 39% (P &lt;0.0001) higher in 45 perimenopausal women and 86% (P &lt;0.0001) higher in 429 postmenopausal women (mean age, 64 years). Baseline serum CTX correlated negatively with changes of bone mass measured at the mid (r = −0.23; P &lt;0.0001) and distal (r = −0.27; P &lt;0001) radius. Postmenopausal women with serum CTX greater than the mean + 2 SD values in premenopausal women accounted for 42% of the population, lost bone at the mid radius on average eightfold more rapidly than the other women (−0.27% ± 2.92% vs −2.25% ± 3.95%; P &lt;0.0001), and had increased risk of fracture with a relative risk (95% confidence interval) of 1.8 (1.01–3.1) after adjustment for physical activity.
Conclusions: The automated assay for serum CTX is precise and predicts rate of bone loss and fracture risk in postmenopausal women. Because it is convenient to use and has high throughput, this serum bone resorption marker may be useful for the investigation of patients with osteoporosis.
The Chemical Work of Alexander and Jane Marcet
Authors: Rosenfeld Louis 
Published: January 2020

Abstract
Alexander Marcet was an authority on urinary calculi and their analysis when few medical practitioners appreciated the usefulness of chemistry in the explanation and treatment of disease. In An Essay on The Chemical History and Medical Treatment of Calculous Disorders, he described the discovery of an xanthine stone. He drew line illustrations of simple chemical apparatus useful for bedside analysis. His microtechnique used drops of solution and pinhead pieces of calculi; reagents were acids and alkalies and the blowpipe in conjunction with a small alcohol lamp. He reported the earliest description of a disorder later named “alcaptonuria”. Marcet’s work and that of a few others, on the chemical composition of urine and calculi, laid the foundations of our present knowledge. Between 1807 and 1820, his lectures to the medical students at Guy’s Hospital were illustrated by experiments.
Jane Haldimand Marcet wrote the very popular Conversations on Chemistry (16 editions in Great Britain). Her book dominated elementary chemical instruction during the first half of the 19th century. She followed Lavoisier’s scheme of classification and explained chemical reactions in terms of affinity, aggregation, gravitation, and repulsion. Her advocacy that experimentation accompany lecture was new. The availability of serious scientific education in the new women’s academies set the stage for increasing women’s involvement in science. She also published a series of Conversations. The topics were Political Economy, Natural Philosophy, and Vegetable Physiology.
Quantification of HER2/neu Gene Amplification by Competitive PCR Using Fluorescent Melting Curve Analysis
Authors: Lyon Elaine , Millson Alison , Lowery Mary C , Woods Rachel , Wittwer Carl T 
Published: January 2020

AbstractBackground: Molecular detection methods for HER2/neu gene amplification include fluorescence in situ hybridization (FISH) and competitive PCR. We designed a quantitative PCR system utilizing fluorescent hybridization probes and a competitor that differed from the HER2/neu sequence by a single base change.Methods: Increasing twofold concentrations of competitor were coamplified with DNA from cell lines with various HER2/neu copy numbers at the HER2/neu locus. Competitor DNA was distinguished from the HER2/neu sequence by a fluorescent hybridization probe and melting curve analysis on a fluorescence-monitoring thermal cycler. The percentages of competitor to target peak areas on derivative fluorescence vs temperature curves were used to calculate copy number.Results: Real-time monitoring of the PCR reaction showed comparable relative areas throughout the log phase and during the PCR plateau, indicating that only end-point detection is necessary. The dynamic range was over two logs (2000–250 000 competitor copies) with CVs &lt;20%. Three cell lines (MRC-5, T-47D, and SK-BR-3) were determined to have gene doses of 1, 3, and 11, respectively. Gene amplification was detected in 3 of 13 tumor samples and was correlated with conventional real-time PCR and FISH analysis.Conclusion: Use of relative peak areas allows gene copy numbers to be quantified against an internal competitive control in &lt;1 h.
Relationship between Triglyceride Concentrations and LDL Size Evaluated by Malondialdehyde-modified LDL
Authors: Kondo Akira , Muranaka Yoshinori , Ohta Isao , Notsu Kazuaki , Manabe Mitsuhisa , Kotani Kazuo , Saito Kazunori , Maekawa Masato , Kanno Takashi 
Published: January 2020

AbstractBackground: Hypertriglyceridemia is associated with decreased HDL-cholesterol (HDL-C) and increased small dense LDL. In addition, small dense LDL is known to be susceptible to oxidation.Methods: We measured LDL particle size, using gradient gel electrophoresis, and malondialdehyde-modified LDL (MDA-LDL), using an ELISA, and investigated the association between triglyceride (TG) concentrations, LDL size, and MDA-LDL.Results: TG concentrations correlated negatively with the predominant LDL size (r = −0.650) and HDL-C concentration (r = −0.556). The relationship between TG concentration and LDL size, evaluated by measuring MDA-LDL, distinguished subgroups derived from four subfractions of TG concentrations and four distribution ranges of LDL size. These experiments indicated that there is a threshold for oxidation susceptibility at an LDL size of 25.5 nm and a TG concentration of 1500 mg/L. To investigate the relationship between LDL size, MDA-LDL concentration, and other lipids (TGs, HDL-C, apolipoprotein B, and total cholesterol), we evaluated them in control subjects and patients with diabetes mellitus or hypertriglyceridemia. When the size range for normal LDL was postulated to be 25.5 ≤ φ (LDL diameter) &lt; 26.5 nm, the MDA-LDL concentration was significantly higher in the subgroups of patients with LDL in the size range 24.5 ≤ φ &lt; 25.5 nm compared with patients with normal LDL. This result also suggests that the threshold is at a LDL size of 25.5 nm.Conclusion: The threshold for oxidation susceptibility coincided with the point of LDL size separation between the LDL subclass patterns A and B as an atherosclerotic risk.