bluuebunny/crossref_metadata_2025 huggingface dataset:
Preface
Authors: Cohen Charles L.
Published: January 2020

Abraham is a figure from antiquity; stories about the putative discoverer of the One God contain material that may date from the third millennium bce. His name entered Old English from Hebrew as early as the eleventh century ce, although the term “Abrahamic” did not appear in its original sense—“relating to, or characteristic of the biblical patriarch, Abraham”—until 1699. “Abrahamic” in this book means principally “belonging to the group of religions comprising Judaism, Christianity, and Islam, which trace their origin to Abraham,” a twentieth-century usage. This definition updates the commonplace observation that Judaism, Christianity, and Islam—the “Abrahamic religions”—are somehow closely related. Not everyone likes this expression or its categorical implications. Some scholars object that the term “Abrahamic” can mislead, especially insofar as it may exaggerate the three religions’ similarities and the likelihood that Jews, Christians, and Muslims can set their differences aside. Others regard the categorization itself as incoherent, given adherents’ fundamental divisions over matters such as what scriptures they consider canonical and how they understand God’s nature....
Superstition: A Very Short Introduction
Authors: Vyse Stuart
Published: January 2020

Do you touch wood for luck, or avoid hotel rooms on floor thirteen? Would you cross the path of a black cat, or step under a ladder? Despite the dominance of science in today’s world, superstitious beliefs—both traditional and new—remain surprisingly popular. Where did these superstitions come from, and why do they persist today? Superstition: A Very Short Introduction explores the nature and surprising history of superstition from antiquity to the present. It takes an exciting look at the varieties of popular superstitious beliefs today and the psychological reasons behind their continued existence, as well as the likely future course of superstition in our increasingly connected world.
2. Productive ambiguity
Authors: Heilbron J. L.
Published: January 2020

‘Productive ambiguity’ begins with Bohr’s move to Cambridge in 1911 to work with J. J. Thompson on the electron theory and to publish an English translation of his thesis. He did not flourish in Cambridge, however, and moved to Manchester in early 1912 to study under Ernest Rutherford. He soon took an interest in the work of another researcher in the laboratory, Charles Galton Darwin, who was wrestling with the problem of how electrons in a nuclear atom interact with passing alpha particles. Consideration of Darwin’s problem prompted Bohr to discover the radical mechanical instability of the nuclear atom, a result for which his thesis and his philosophy had prepared him. He exploited the instability to develop his quantum atom. His several attempts to ground his invention in existing physics give a precious insight into his mind at work, into his way of entertaining several contradictory formulations of his thought at the same time.
4. Presenting art history
Authors: Arnold Dana
Published: January 2020

‘Presenting art history’ considers the different ways of presenting art history, and especially the importance of the gallery or museum. It maps out the development of collections from the cabinet of curiosities to the private and corporate sponsor and collector of today and discusses the impact the amassing of objects has had on their perceived value and on the histories of art, and how writing about objects can affect their ‘value’. The emergence of the prestige building by a star architect to house art collections has become an increasingly global phenomenon, which along with ‘blockbuster’ exhibitions has had a significant impact on the presentation and understanding of art history.
Polymethyl Methacrylate (PMMA) in the Treatment of a Case of Hemifacial Microsomia
Authors: Milhomem Anália Cirqueira , Jorge Isabella Mendes de Souza , Costa Eduardo Luiz da , Vinaud Marina Clare , Lino Júnior Ruy de Souza
Published: January 2020

Hemifacial microsomia (HMF) is a morphological alteration characterized by facial deformities. These alterations are a consequence of a congenital anomalous development of the first and second branchial arches. It may present a genetic or environmental origin or a mixture of both and is considered mostly multifactorial. The clinical presentation varies; however, some characteristics are predominant such as unilateral mandible hypoplasia, agenesis or malformation of the auricular pavilion, and agenesis or malformation of the eye globe. The aim of this paper was to report a clinical case of a patient with late diagnosis of HMF which presented multiple deformities and received treatment with polymethyl methacrylate (PMMA) implant in different concentrations. Aiming for facial harmony, the PMMA implant occurred in the following regions: canine fossa, nasolabial sulcus, mandible, Bichat Ball, chin outline, lip contour, nose base, columella, nose tip, and dorsum. The treatment resulted in significant improvement in the facial symmetry.

Level of Evidence: 5
Can machine learning consistently improve the scoring power of classical scoring functions? Insights into the role of machine learning in scoring functions
Authors: Shen Chao , Hu Ye , Wang Zhe , Zhang Xujun , Zhong Haiyang , Wang Gaoang , Yao Xiaojun , Xu Lei , Cao Dongsheng , Hou Tingjun
Published: January 2020

How to accurately estimate protein–ligand binding affinity remains a key challenge in computer-aided drug design (CADD). In many cases, it has been shown that the binding affinities predicted by classical scoring functions (SFs) cannot correlate well with experimentally measured biological activities. In the past few years, machine learning (ML)-based SFs have gradually emerged as potential alternatives and outperformed classical SFs in a series of studies. In this study, to better recognize the potential of classical SFs, we have conducted a comparative assessment of 25 commonly used SFs. Accordingly, the scoring power was systematically estimated by using the state-of-the-art ML methods that replaced the original multiple linear regression method to refit individual energy terms. The results show that the newly-developed ML-based SFs consistently performed better than classical ones. In particular, gradient boosting decision tree (GBDT) and random forest (RF) achieved the best predictions in most cases. The newly-developed ML-based SFs were also tested on another benchmark modified from PDBbind v2007, and the impacts of structural and sequence similarities were evaluated. The results indicated that the superiority of the ML-based SFs could be fully guaranteed when sufficient similar targets were contained in the training set. Moreover, the effect of the combinations of features from multiple SFs was explored, and the results indicated that combining NNscore2.0 with one to four other classical SFs could yield the best scoring power. However, it was not applicable to derive a generic target-specific SF or SF combination.
Domain-adversarial multi-task framework for novel therapeutic property prediction of compounds
Authors: Xie Lingwei , He Song , Zhang Zhongnan , Lin Kunhui , Bo Xiaochen , Yang Shu , Feng Boyuan , Wan Kun , Yang Kang , Yang Jie , Ding Yufei
Published: January 2020

Motivation

With the rapid development of high-throughput technologies, parallel acquisition of large-scale drug-informatics data provides significant opportunities to improve pharmaceutical research and development. One important application is the purpose prediction of small-molecule compounds with the objective of specifying the therapeutic properties of extensive purpose-unknown compounds and repurposing the novel therapeutic properties of FDA-approved drugs. Such a problem is extremely challenging because compound attributes include heterogeneous data with various feature patterns, such as drug fingerprints, drug physicochemical properties and drug perturbation gene expressions. Moreover, there is a complex non-linear dependency among heterogeneous data. In this study, we propose a novel domain-adversarial multi-task framework for integrating shared knowledge from multiple domains. The framework first uses an adversarial strategy to learn target representations and then models non-linear dependency among several domains.

Results

Experiments on two real-world datasets illustrate that our approach achieves an obvious improvement over competitive baselines. The novel therapeutic properties of purpose-unknown compounds that we predicted have been widely reported or brought to clinics. Furthermore, our framework can integrate various attributes beyond the three domains examined herein and can be applied in industry for screening significant numbers of small-molecule drug candidates.

Availability and implementation

The source code and datasets are available at https://github.com/JohnnyY8/DAMT-Model.

Supplementary information

Supplementary data are available at Bioinformatics online.
Estimation from cross-sectional data under a semiparametric truncation model
Authors: Heuchenne C , De Uña-Álvarez J , Laurent G
Published: January 2020

Cross-sectional sampling is often used when investigating inter-event times, resulting in left-truncated and right-censored data. In this paper, we consider a semiparametric truncation model in which the truncating variable is assumed to belong to a certain parametric family. We examine two methods of estimating both the truncation and the lifetime distributions. We obtain asymptotic representations of the estimators for the lifetime distribution and establish their weak convergence. Both of the proposed estimators perform better than Wang’s (1991) nonparametric maximum likelihood estimator in terms of the integrated mean squared error, when the parametric family for the truncation is sufficiently close to its true distribution. The full likelihood approach is preferable to the conditional likelihood approach in estimating the lifetime distribution, though not necessarily the truncation distribution. In an application to Alzheimer’s disease data, hypothesis tests reject the uniform truncation distribution, but several other parametric models lead to similar behaviour of the truncation and lifetime distributions after disease onset.
Two distinct neuroanatomical subtypes of schizophrenia revealed using machine learning
Authors: Chand Ganesh B , Dwyer Dominic B , Erus Guray , Sotiras Aristeidis , Varol Erdem , Srinivasan Dhivya , Doshi Jimit , Pomponio Raymond , Pigoni Alessandro , Dazzan Paola , Kahn Rene S , Schnack Hugo G , Zanetti Marcus V , Meisenzahl Eva , Busatto Geraldo F , Crespo-Facorro Benedicto , Pantelis Christos , Wood Stephen J , Zhuo Chuanjun , Shinohara Russell T , Shou Haochang , Fan Yong , Gur Ruben C , Gur Raquel E , Satterthwaite Theodore D , Koutsouleris Nikolaos , Wolf Daniel H , Davatzikos Christos
Published: January 2020

Neurobiological heterogeneity in schizophrenia is poorly understood and confounds current analyses. We investigated neuroanatomical subtypes in a multi-institutional multi-ethnic cohort, using novel semi-supervised machine learning methods designed to discover patterns associated with disease rather than normal anatomical variation. Structural MRI and clinical measures in established schizophrenia (n = 307) and healthy controls (n = 364) were analysed across three sites of PHENOM (Psychosis Heterogeneity Evaluated via Dimensional Neuroimaging) consortium. Regional volumetric measures of grey matter, white matter, and CSF were used to identify distinct and reproducible neuroanatomical subtypes of schizophrenia. Two distinct neuroanatomical subtypes were found. Subtype 1 showed widespread lower grey matter volumes, most prominent in thalamus, nucleus accumbens, medial temporal, medial prefrontal/frontal and insular cortices. Subtype 2 showed increased volume in the basal ganglia and internal capsule, and otherwise normal brain volumes. Grey matter volume correlated negatively with illness duration in Subtype 1 (r = −0.201, P = 0.016) but not in Subtype 2 (r = −0.045, P = 0.652), potentially indicating different underlying neuropathological processes. The subtypes did not differ in age (t = −1.603, df = 305, P = 0.109), sex (chi-square = 0.013, df = 1, P = 0.910), illness duration (t = −0.167, df = 277, P = 0.868), antipsychotic dose (t = −0.439, df = 210, P = 0.521), age of illness onset (t = −1.355, df = 277, P = 0.177), positive symptoms (t = 0.249, df = 289, P = 0.803), negative symptoms (t = 0.151, df = 289, P = 0.879), or antipsychotic type (chi-square = 6.670, df = 3, P = 0.083). Subtype 1 had lower educational attainment than Subtype 2 (chi-square = 6.389, df = 2, P = 0.041). In conclusion, we discovered two distinct and highly reproducible neuroanatomical subtypes. Subtype 1 displayed widespread volume reduction correlating with illness duration, and worse premorbid functioning. Subtype 2 had normal and stable anatomy, except for larger basal ganglia and internal capsule, not explained by antipsychotic dose. These subtypes challenge the notion that brain volume loss is a general feature of schizophrenia and suggest differential aetiologies. They can facilitate strategies for clinical trial enrichment and stratification, and precision diagnostics.
Evaluation of urinary metanephrine and normetanephrine enzyme immunoassay (ELISA) kits by comparison with isotope dilution mass spectrometry
Authors: Wolthers Bert G , Kema Ido P , Volmer Marcel , Wesemann Reinhard , Westermann Jürgen , Manz Bernhard
Published: January 2020

Determination of urinary 3-O-methylated catecholamines (metanephrines) is generally considered a principal test for the clinical chemical diagnosis of pheochromocytoma and is currently performed predominantly with chromatographic techniques such as gas–liquid chromatography and HPLC. Enzyme immunoassays based on microtiter plate technology have recently been developed for the quantitative determination of urinary metanephrine (M) and normetanephrine (NM). We compared the results for urinary M and NM determined by these ELISA methods with those obtained by a recently developed isotope dilution mass spectrometric method. From this comparative study we can conclude that the investigated ELISA methods are applicable in the quantification of urinary M and thus can be successfully used to establish the diagnosis of pheochromocytoma. These relatively simple methods can be executed in any clinical laboratory and in time may replace the present, more complicated, chromatographic techniques.
Association between genetic variations of apo AI-CIII-AIV cluster gene and hypertriglyceridemic subjects
Authors: Hong Seung Ho , Park Woo Hyun , Lee Chung Choo , Song Jung Han , Kim Jin Q
Published: January 2020

Several studies have suggested that genetic variations of the apolipoprotein (apo) AI-CIII-AIV cluster gene are associated with hyperlipidemia or atherosclerosis. These investigations were carried out mainly with Caucasian groups; there have been few associated studies involving non-Caucasian groups. This study was conducted to elucidate the association between five restriction fragment length polymorphisms (RFLPs) of the apo AI-CIII-AIV cluster gene and Korean hypertriglyceridemic subjects. The rare allele frequencies of the XmnI and SstI polymorphic sites in the patients were significantly higher than those of the control group (P <0.05). These two polymorphic sites had relation to linkage disequilibrium in the hypertriglyceridemic subjects (Δ = −0.2733). In addition, S2 allele frequency of the SstI RFLP in Koreans was more frequent than that of Caucasians reported previously. The rare allele of XmnI and SstI polymorphic sites was associated with increased triglyceride concentrations in the hypertriglyceridemic group (P <0.005). Koreans have a much lower prevalence of hyperlipidemia than Caucasians. Nevertheless, this study showed a similar trend with results from Caucasian groups, thereby confirming that genetic variations of the apo AI-CIII-AIV cluster gene are likely to be significant markers for hypertriglyceridemic sub-jects. Thus, RFLP loci of the apo AI-CIII-AIV cluster gene may be a useful genetic marker for clinical or population studies.
Development of reverse dot-blot system for screening of mitochondrial DNA mutations associated with Leber hereditary optic atrophy
Authors: Schollen Els , Vandenberk Petra , Cassiman Jean-Jacques , Matthijs Gert
Published: January 2020

We developed a diagnostic test based on the reverse dot-blot principle, in which five mitochondrial point mutations responsible for Leber hereditary optic neuropathy (LHON) were screened simultaneously. A series of wild-type and mutant oligonucleotides representing each mutation were covalently bound to a single nylon membrane strip. The target sites were amplified in a multiplex PCR and the products were hybridized to the membrane. Detection is based on chemiluminescence. To test the developed assay, 47 patients suspected of having LHON were screened. In 11 cases (23%) the diagnosis of LHON could be confirmed (3460, 1; 9804, 1; 11778, 5; 14484, 3; 15257, 1). The results suggest that the clinical identification of the mitochondrial defect is not trivial and the availability of a rapid screening method simplifies the molecular analysis of these cases.
Assessing liver function and hyperbilirubinemia in the newborn
Authors: Rosenthal Philip
Published: January 2020

In clinical practice, “liver function” is assessed by either measuring the concentration of substances produced by the hepatocyte, measuring the serum content of substances that are changed by hepatocyte damage, evaluating the serum concentrations of substances released from the cells as a result of injury, assessing the ability of the liver to perform a metabolic task such as conjugation or detoxification, or by measuring enzyme activity and substrate content of the cell and its organelles. After birth, with cessation of placental function, the neonatal liver must assume many different tasks. Distinct developmental sequences rapidly progress for numerous hepatic functions as the newborn adapts to its environment. This manuscript is an attempt to provide guidelines for the evaluation and management of the newborn infant when assessing liver function and hyperbilirubinemia. These guidelines, like all sets of guidelines, are only recommendations and do not substitute for good clinical judgment based upon the individual circumstances of each patient.
Use of the laboratory in prediction of outcome in the high-risk newborn
Authors: Synnes Anne R
Published: January 2020

This paper reviews our ability to predict survival and neurodevelopmental outcome in the newborn period. Traditionally, prognosis is based on individual risk factors or disease states. The laboratory plays an important role in diagnosing some of these. For example, prenatal and newborn screening are important in the diagnosis of chromosomal abnormalities and inborn errors of metabolism. Abnormal bilirubin, glucose, and pH values in the newborn period are risk factors for death and abnormal neurodevelopment, and the degree of abnormality imparts additional information. Many newborns have multisystem disorders, and it is only when multiple variables are considered that outcome can be predicted. Three neonatal scores that incorporate multiple variables are discussed. Methodologic difficulties in determining outcome are reviewed and illustrated with survival and morbidity rates of very premature babies. The laboratory is one of many prognostic variables. The evaluation of how laboratory services are provided is difficult but important.
Bone sialoprotein in serum of patients with malignant bone diseases
Authors: Withold Wolfgang , Armbruster Franz P , Karmatschek Markus , Reinauer Hans
Published: January 2020

Bone sialoprotein (BS), a protein synthesized by osteoblasts and osteoclasts and highly modified posttranslationally, constitutes a predominant fraction of the noncollagenous organic matrix in human bone. We report an assessment of serum concentrations of BS in patients with malignant bone diseases. In patients with bone metastases (according to scintigraphic criteria), serum BS concentrations were greater than in patients without bone metastases (P <0.05). However, ROC curve analysis revealed that serum BS was inferior to serum bone alkaline phosphatase in discriminating between patients with and without bone metastases. Patients with bone metastases showed a weak correlation between serum BS concentrations and bone formation markers. Only “traditional” markers of bone formation—but not BS—were correlated with urinary deoxypyridinoline (P <0.01). Liver and kidney dysfunction had no significant influence on BS values in these patients (as assessed by analysis of variance; P >0.05). In multiple myeloma patients treated with corticosteroids and bisphosphonates, BS concentrations were lower than in tumor patients without bone metastases (P <0.001), and the correlation between BS concentrations and the number of bisphosphonate courses applied was significant (r = −0.578; P <0.05). In postmenopausal women, serum BS concentrations averaged 142% greater than in premenopausal women. Further studies should be done, therefore, to elucidate whether serum BS is able to predict high bone turnover after menopause.
Receiver operating characteristic plots to evaluate Guthrie, Wallac, and Isolab phenylalanine kit performance for newborn phenylketonuria screening
Authors: Wang Stephen T , Pizzolato Sam , Demshar Helen P
Published: January 2020

We used ROC plots to evaluate the clinical performance of the Guthrie, Wallac, and Isolab assays for newborn phenylketonuria (PKU) screening and assessed the screening discriminatory power of these three assays by the area under the ROC plot, Youden’s J index, and the likelihood ratio. The use of these plots not only allows us to pinpoint the exact cutoff value in screening, but also provides a direct comparison of these three different assays in clinical outcome performance. The optimum cutoff for the newborn PKU screening is a blood phenylalanine concentration of 0.30, 0.27, and 0.18 mmol/L for the Guthrie, Wallac, and Isolab assays, respectively. We conclude that the Wallac and Isolab kits, like the Guthrie assay, are suitable for newborn PKU screening.
Prostate-specific antigen in serum during the menstrual cycle
Authors: Zarghami Nosratollah , Grass Linda , Sauter Edward R , Diamandis Eleftherios P
Published: January 2020

We previously found that prostate-specific antigen (PSA) expression in the female breast is regulated by steroid hormones and their receptors. We have now examined whether the PSA concentration in serum changes during the menstrual cycle of healthy women. Among 14 women studied, 3 had serum PSA ≥4 ng/L; their changes in PSA content during the menstrual cycle were studied in 7 informative cycles. We found that PSA concentrations in serum are highest during the mid- to late follicular phase, drop continuously with a half-life of 3–5 days between the late follicular phase and midcycle, and reach a minimum during the mid- to late luteal phase. PSA changes do not correlate with changes in lutropin (LH), follitropin (FSH), or estradiol concentrations. However, PSA peaks seem to follow the progesterone concentration peaks, with a delay of 10–12 days. Sera of some volunteers were tested for their ability to upregulate PSA protein and PSA mRNA in a tissue culture system based on the T-47D breast carcinoma cell line. Only sera obtained during the mid- to late luteal phase were able to upregulate the PSA mRNA and protein. In stimulation experiments in vitro, progesterone, but not LH, FSH, estradiol, human chorionic gonadotropin, prolactin, or growth hormone, was able to upregulate PSA mRNA and protein in the T-47D cell line. These data suggest that PSA is produced in a cyclical manner during the menstrual cycle.
Relation between lipoprotein(a) concentrations in patients with acute-phase response and risk analysis for coronary heart disease
Authors: Min Won-Ki , Lee Jae Ok , Huh Jung Won
Published: January 2020

This study investigated whether lipoprotein(a) [Lp(a)] is an acute-phase reactant that can cause important bias in risk factor analysis for coronary heart disease among patients with an acute-phase response (APR patients). To determine whether serum Lp(a) concentrations increase among APR patients, we compared the Lp(a) concentrations and apolipoprotein(a) [apo(a)] phenotypes of 100 controls with those of a random sampling of 100 APR patients. Serum Lp(a) concentration was measured by ELISA; Lp(a) phenotyping was performed by electrophoresis on sodium dodecyl sulfate–polyacrylamide gel. Lp(a) was significantly (P <0.0001) higher among APR patients (mean ± SD 0.300 ± 0.284 g/L) than among controls (0.118 ± 0.193 g/L) even though the distribution of apo(a) phenotypes did not differ significantly. The 100 APR patients were grouped into 4 categories: 48 patients with infections, 25 postoperative patients, 17 patients with tumors, and 10 patients with other diseases, all of whom showed substantially higher Lp(a) values than did the controls. For the S5, S4S5, S5S5, and S4 phenotypes, the mean concentrations of serum Lp(a) were substantially higher among the APR patients.
Candidate reference methods for hemoglobin A1c based on peptide mapping
Authors: Kobold Uwe , Jeppsson Jan-Olof , Dülffer Thomas , Finke Andreas , Hoelzel Wieland , Miedema Kor
Published: January 2020

A reference method that specifically measures hemoglobin (Hb) A1c is an essential part of the reference system for the international standardization of Hb A1c/glycohemoglobin. We have developed a new method for quantification, based on the specific N-terminal residue of the hemoglobin β-chains. Enzymatic cleavage of the intact hemoglobin molecule with endoproteinase Glu-C has been optimized to obtain the β-N-terminal hexapeptides of Hb A1c and Hb A0. These peptides have been separated by reversed-phase HPLC and quantitated by electrospray ionization-mass spectrometry (method A) or by capillary electrophoresis (method B). With these peptides and hyphenated separation techniques, it has been possible to overcome the insufficient resolution of currently used protein separation systems for Hb A1c.
Assessment of monoethylglycinexylidide as measure of liver function for patients with chronic viral hepatitis
Authors: Elin Ronald J , Fried Michael W , Sampson Maureen , Ruddel Mark , Kleiner David E , DiBisceglie Adrian M
Published: January 2020

The liver metabolizes lidocaine by oxidative deethylation to form monoethylglycinexylidide (MEGX), an analyte proposed as an index of liver function. We determined MEGX and lidocaine serum concentrations with the TDx (Abbott Laboratories) at baseline and 15, 30, 60, and 90 min after the intravenous administration of lidocaine (1 mg/kg), analyzing specimens from 12 apparently healthy volunteers and 40 patients with chronic viral hepatitis diagnosed by liver biopsy and serum tests. The patients were grouped on the basis of the histology activity index. The following laboratory tests were performed on serum specimens from all subjects: albumin (ALB), alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase, total bilirubin, and prothrombin time. The results showed no significant difference among the four groups for the concentrations of MEGX, lidocaine, and lidocaine/MEGX at the four time points. However, the concentrations of ALB, ALT, AST, AST/ALT, and prothrombin time were substantially different among the four groups. Thus, we conclude that assay of MEGX in our patients with chronic viral hepatitis did not contribute to the assessment of liver function when compared with apparently healthy volunteers and traditional tests of liver function.
Graphical interpretation of analytical data from comparison of a field method with a Reference Method by use of difference plots
Authors: Petersen Per Hyltoft , Stöckl Dietmar , Blaabjerg Ole , Pedersen Bent , Birkemose Erling , Thienpont Linda , Lassen Jens Flensted , Kjeldsen Jens
Published: January 2020

Various viewpoints have been offered regarding the appropriate use of scatter plots or difference plots (bias plots or residual plots) in comparing analytical methods. In many of these discussions it seems the basic concepts of identity (within inherent imprecision) and acceptability based on analytical goals (analytical quality specifications) have been forgotten. With the increasing number of Reference Methods in laboratory medicine, these basic concepts are becoming more important in validation of field methods. Here we describe a simple and effective graphical test of these hypotheses (identity and acceptability) by use of difference plots. These plots display the underlying hypothesis before the measured differences are plotted and allow interpretation of the results according to specific criteria. We further describe simple but effective interpretations of the data, when the hypothesis is not fulfilled, by using two data sets drawn from comparisons of field methods for S-creatinine with a Reference Method for this analyte. The difference plot is a graphical tool with related simple statistics for comparison of a field method with a Reference Method, focusing on (a) identity within the inherent analytical imprecision or (b) acceptability within analytical quality specifications. Calculation of the standard deviation of the differences is an indispensable tool for evaluation of aberrant-sample bias (matrix effects).
Evidence that serum NTx (collagen-type I N-telopeptides) can act as an immunochemical marker of bone resorption
Authors: Clemens J Daniel , Herrick Michael V , Singer Frederick R , Eyre David R
Published: January 2020

Previous studies have shown that immunoassay of urinary NTx (cross-linked N-telopeptides of type I collagen) provides a responsive index of human bone resorption. Here we report by a sensitive immunoassay that NTx is present in serum and is suppressed appropriately in patients with Paget disease of bone by bisphosphonate antiresorptive therapy. The monoclonal antibody (1H11) developed against urinary NTx was applied in a sensitive chemiluminescence format. Results for human serum and urine showed parallel inhibition curves. The NTx concentrations in paired serum and urine samples from individual patients correlated well when urinary concentrations were normalized to creatinine concentrations (in premenopausal and postmenopausal women and Paget disease patients, r = 0.90, n = 60). The percentage of NTx suppression from baseline values for Paget disease patients on bisphosphonate therapy was similar for serum and urine. Blood samples drawn from bone marrow at the site of Pagetic lesions in three patients with active disease had as much as 10-fold higher concentrations of NTx than did peripheral blood samples drawn at the same time. The latter finding is consistent with other evidence showing that immunoreactive NTx originates directly during the proteolytic cleavage of bone collagen by osteoclasts rather than, e.g., by degradative processes occurring later in the liver and kidney.
Rapid detection of 21-hydroxylase deficiency mutations by allele-specific in vitro amplification and capillary zone electrophoresis
Authors: Carrera Paola , Barbieri Anna Maria , Ferrari Maurizio , Righetti Pier Giorgio , Perego Marilena , Gelfi Cecilia
Published: January 2020

A quick diagnosis of the classic form of 21-hydroxylase deficiency (simple virilizing and salt wasting) is of great importance, especially for prenatal diagnosis and treatment in pregnancies at risk. A method for simultaneous detection of common point mutations in the P450c21 B gene is here proposed by combining a nested PCR amplification refractory mutation system (ARMS) with capillary zone electrophoresis (CZE) in sieving liquid polymers. In the first PCR, B genes are selectively amplified. In the nested reaction, ARMS-detected wild-type and mutated alleles are separately pooled and resolved by CZE. CZE is performed in coated capillaries in the presence of 30 g/L hydroxyethyl cellulose in the background electrolyte for size separation of the DNA analytes. For high-sensitivity detection the electrophoresis buffer contains the fluorescent dye SYBR Green I. Laser-induced fluorescence detection is obtained by excitation at 488 nm and signal collection at 520 nm. Specificity and reproducibility of the protocols were established by using samples from 75 Italian families with 21-hydroxylase deficiency already genotyped by allele-specific oligonucleotide hybridization or direct sequencing. Whereas dot-blot is time consuming because of the high number of hybridizations with radioactive probes, this present protocol is more rapid, giving sufficient separation on CZE after PCR reactions without preconcentration or desalting of samples.
Capillary isoelectric focusing and high-performance cation-exchange chromatography compared for qualitative and quantitative analysis of hemoglobin variants
Authors: Mario Nathalie , Baudin Bruno , Aussel Christian , Giboudeau Jacqueline
Published: January 2020

We have developed two assays for complete analysis of hemoglobins (Hbs) in the field of hemoglobinopathies: a high-performance cation-exchange liquid chromatography (HPLC) assay on the weak cation-exchanger Poly Cat A and a two-step capillary isoelectric focusing (CIEF) assay on the neutral-coated capillary from Beckman in a narrow pH gradient. The resolution was satisfactory for both HPLC and CIEF and allowed separation of normal and common abnormal Hbs, i.e., Hb A, Hb F, Hb A2, Hb S, Hb C, and Hb E; slight differences were shown for the resolution of unusual variants such as Hb C-Harlem and Hb D-Punjab. The reproducibility of retention times was satisfactory as well for HPLC (CV 3.3%) and CIEF (CV 4.9%). The imprecision of quantification of Hb A2, evaluated at two concentrations, and of Hb F and Hb S was <5%, except for low concentrations of Hb A2quantified by CIEF. Quantitative data obtained for these three Hb forms were highly correlated between the two assays. These results suggest that the new CIEF assay can be competitive with HPLC for complete routine analysis of Hb variants.
Biological variation of International Normalized Ratio for prothrombin times, and consequences in monitoring oral anticoagulant therapy: computer simulation of serial measurements with goal-setting for analytical quality
Authors: Kjeldsen Jens , Lassen Jens Flensted , Petersen Per Hyltoft , Brandslund Ivan
Published: January 2020

Oral anticoagulant therapy (OAT) has a well-established efficacy in prophylaxis and treatment of thromboembolic disorders. Because complications are related to intensity of OAT, optimal control of treatment is mandatory. In studies of OAT, as many as 30% of International Normalized Ratio (INR) measurements for prothrombin times fall outside the therapeutic interval. Preanalytical, analytical, and biological variation all contribute to this. Computer simulations of serial INR measurements were performed for various assumed in-treatment setpoints within the therapeutic interval INR 2.0–3.0 and for an “in-treatment within-subject variation” (CV) of 10.1%. Results are presented in difference plots with therapeutic intervals and critical differences. If the in-treatment setpoint is mid-interval (INR = 2.5), only 5% of simulated INR values fall outside the therapeutic interval. Setpoints deviating from the mid-interval and increases in the in-treatment within-subject variation considerably increase the number of observations outside the therapeutic interval and the critical differences. In conclusion, random variation, biological or analytical, and setpoints (targets) deviating from mid-interval explain a substantial number of the INR values outside therapeutic intervals observed in clinical studies. Analytical imprecision should be kept <5% and analytical bias <±0.2 INR.
Sensitive and specific cytokeratin 18 reverse transcription-polymerase chain reaction that excludes amplification of processed pseudogenes from contaminating genomic DNA
Authors: Tschentscher Peter , Wagener Christoph , Neumaier Michael
Published: January 2020

Processed pseudogenes of residual contaminating genomic DNA interfere with a sensitive detection of cytokeratin 18 (CK18) mRNA by reverse transcription and polymerase chain reaction (RT-PCR). This may cause false-positive results when CK18 mRNA is used as a marker for ectopic tumor cells in specimens from cancer patients. To establish a sensitive CK18 RT-PCR by excluding the amplification of processed pseudogenes, the following strategy was chosen: (a) CK18 pseudogene sequences were cloned from genomic DNA by PCR; (b) cDNA-specific primers were designed on the basis of mismatches between pseudogenes and cDNA; (c) PCR conditions were adjusted to reach maximum sensitivity and specificity. Epithelial cells (1–10) could be detected in 1 mL of blood. Among the numerous CK18 genes homologous to the transcribed gene, at least two different processed pseudogenes exist that are highly homologous to each other and to the exons of the transcribed CK18 gene.
Single-strand conformation polymorphism analysis to detect p53 mutations: characterization and development of controls
Authors: Welsh Judith A , Castrén Katariina , Vähäkangas Kirsi H
Published: January 2020

Single-strand conformation polymorphism (SSCP) analysis is widely used to prescreen mutations in p53 gene. However, standardization of SSCP to detect p53 mutations has rarely been pursued so far. We have developed complete conditions for a temperature-controlled nonradioactive SSCP for mutation detection in amplified p53 exons 4-8, where mutations frequently occur in human tumors. Easily obtainable and clearly distinguishable positive controls were developed by replacing the regular 5′ primers in amplification with primers that include one to three mutated sites. Careful purification of the amplified products by gel electrophoresis appeared to be essential. The efficiency of the method was studied by using previously sequenced samples with p53 mutations and the various positive controls. The use of two temperatures (exon 4: 4 °C and 15 °C; other exons: 4 °C and 20 °C) in combination with other optimized conditions resulted in 98% efficiency in mutation detection, which was considered sufficient for routine screening.
Double-monoclonal immunofluorometric assays for pregnancy-associated plasma protein A/proeosinophil major basic protein (PAPP-A/proMBP) complex in first-trimester maternal serum screening for Down syndrome
Authors: Qin Qiu-Ping , Christiansen Michael , Oxvig Claus , Pettersson Kim , Sottrup-Jensen Lars , Koch Claus , Nørgaard-Pedersen Bent
Published: January 2020

Four double-monoclonal time-resolved immunofluorometric assays (TrIFMAs) have been developed for the specific determination of pregnancy-associated plasma protein A/proeosinophil major basic protein (PAPP-A/proMBP) complex in first-trimester maternal serum samples. The assays have a functional sensitivity of <4 mIU/L and a working range from 4 to 1000 mIU/L. These 4 assays, together with a polyclonal sandwich TrIFMA, were compared for their ability to discriminate between normal pregnancies (n = 149) and pregnancies carrying a Down syndrome fetus (n = 36) in maternal serum screening samples from gestational weeks 4–13. In 26 Down syndrome pregnancies from gestational weeks 7–12, the median PAPP-A multiples of the median concentration in controls (MoMs) determined by monoclonal antibody combinations 234–3/234–2*, 234–4/234–2*, 234–4/234–5*, and 234–5/234–6* were 0.35, 0.37, 0.42, and 0.44, respectively, whereas the median MoM determined by the polyclonal assay was 0.56. ROC curve analysis also showed that better overall diagnostic accuracy and detection rates were achieved by the monoclonal TrIFMAs than by the polyclonal TrIFMA. This report is the first to describe assays that specifically measure PAPP-A/proMBP complex without possible interference from other proMBP-containing complexes.
Differential reactivity of cardiac and skeletal muscle from various species in a cardiac troponin I immunoassay
Authors: O’Brien Peter J , Landt Yvonne , Ladenson Jack H
Published: January 2020

To identify a blood test that can differentiate cardiac from skeletal muscle injury in animals, we compared tissue reactivities for various species with the use of an immunoassay for human cardiac troponin I (cTnI). Tissue reactivity varied as a function of the homology of tissue troponin with human cTnI. Cardiac reactivity in large mammals was equivalent to cTnI, 9.8 ± 0.6 mg/g, and was 2-fold, 10-fold, and 100-fold greater than in small mammals, birds, and fish, respectively. Skeletal muscle reactivity was equivalent to cTnI, 5.1 ± 0.6 μg/g, in all species except fish, in which it was 50% lower. The ratio of reactivities of cardiac and skeletal muscle was: 1800 in large mammals, 1100 in small mammals, 230 in birds, and 43 in fish. We conclude that cTnI is a powerful candidate in mammals, a possible candidate in birds, but unlikely to be of use in fish as a sensitive and tissue-selective diagnostic test for cardiac injury.
Apolipoprotein B and AI distributions in the United States, 1988–1991: results of the National Health and Nutrition Examination Survey III (NHANES III)
Authors: Bachorik Paul S , Lovejoy Kathleen L , Carroll Margaret D , Johnson Clifford L
Published: January 2020

Serum apolipoproteins (apo) B and AI were measured in a probability sample of the noninstitutionalized US civilian population, ages ≥4 years, which included non-Hispanic whites, non-Hispanic blacks, and Mexican-Americans. Apo B concentrations were the same in males and females, lower in black males than in other males, low in childhood (∼0.80 g/L) and increasing to ∼1.2 g/L in adults, and higher in younger women on hormones. Apo AI was higher in females than males, higher in blacks than in others, remained constant from childhood to adulthood (∼1.35 g/L) in males, but increased with age (∼1.30 g/L to ∼1.55 g/L) in females, and was higher in women taking hormones. These are the first national probability estimates of apo B and apo AI in the US and are referable to the WHO-IFCC First International Reference Materials for apo AI and B.
Low plasma vitamin A concentrations in familial combined hyperlipidemia
Authors: Ribalta Josep , LaVille Agnes E , Girona Josefa , Vallvé Joan C , Masana Lluís
Published: January 2020

As many as 20% of the survivors of acute myocardial infarction present with the heritable form of hyperlipidemia, termed familial combined hyperlipidemia (FCHL). Some of the genes reported to be involved in this disorder, such as those for lipoprotein lipase (LPL) and apolipoprotein (apo) C-III, are controlled by a peroxisome proliferator-activated receptor (PPAR)/retinoic acid receptor X (RXR) regulatory system, which is retinoic acid dependent. If, as we hypothesized, the availability of retinoic acid or its precursor retinol (vitamin A) could be altered in FCHL, this could help explain some aspects of the phenotypic expression of the disease. We therefore measured plasma retinol concentrations in 30 FCHL subjects and 56 controls. Plasma retinol concentrations in FCHL subjects were significantly lower than that of control subjects (1.96 ± 0.83 μmol/L vs 2.91 ± 1.23 μmol/L, respectively; P <0.0001). This novel finding of significantly decreased concentrations of plasma retinol in FCHL relative to control subjects gives support to the hypothesis that vitamin A might be involved in the expression of this disorder.
Plasma and erythrocyte vitamin E content in asymptomatic hypercholesterolemic subjects
Authors: Simon Emmanuelle , Paul Jean-Louis , Soni Théophile , Simon Alain , Moatti Nicole
Published: January 2020

The present study was designed to assess plasma and erythrocyte vitamin E concentrations in 57 asymptomatic hypercholesterolemic (HC) men compared with 56 normocholesterolemic (NC) men. Vitamin E concentrations were determined by using a reversed-phase HPLC method. Compared with NC subjects, HC men had a significantly lower red blood cell (RBC) vitamin E content in spite of their normal plasma vitamin E concentration. This study demonstrates that total plasma vitamin E concentration is not a suitable predictor of cell vitamin E status and suggests an abnormal transfer of tocopherol between plasma and RBCs in HC men. Moreover, the RBCs of HC men were more susceptible to a peroxidative stress. The strong correlation between RBC susceptibility to oxidation and RBC vitamin E content suggests that the low RBC vitamin E content found in HC men has physiological consequences on the RBC oxidation.
Medians for second-trimester maternal serum α-fetoprotein, human chorionic gonadotropin, and unconjugated estriol; differences between races or ethnic groups
Authors: Benn Peter A , Clive Jonathan M , Collins Roxanne
Published: January 2020

Second-trimester maternal serum α-fetoprotein (AFP), human chorionic gonadotropin (hCG), and unconjugated estriol (uE3) are routinely measured in screening fetuses at high risk for Down syndrome or open neural tube defects (ONTD). For test interpretation, individual patient values of these three analytes are related to population-derived median values. We evaluated data from >21 000 pregnancies to determine the extent of race-specific differences in median concentrations. For samples at most gestational ages, median AFP, hCG, and uE3 values for white, black, Hispanic, and other patients were all significantly different. Differences remained significant even when data were corrected for patient weights. For each analyte, the extent of the variation was not the same at different gestational ages. Differences in median values across race/ethnicity groups appear to have only a small impact in Down syndrome screening but it may be appropriate to use alternative sets of AFP medians or adjustment factors to AFP medians for some Asian populations receiving ONTD screening.
Critical difference between serial measurements of CK-MB mass to detect myocardial damage
Authors: de Winter Robbert J , Koster Rudolph W , van Straalen Jan P , Gorgels Jozef P M C , Hoek Frans J , Sanders Gerard T
Published: January 2020

To assess the critical difference in serial measurements of CK-MBmass and the ability of this critical difference to detect myocardial damage, we studied 110 patients in whom an acute myocardial infarction (AMI) had been ruled out. Blood samples were drawn at 3, 4, 5, 6, 7, 8, 12, 16, 20, and 24 h after onset of symptoms. With a critical difference of 72.6%, an increase of >2.0 μg/L between two CK-MBmass measurements was determined to be significant. Twenty-three of the non-AMI patients had an increase in CK-MBmass >2.0 μg/L, but five of these did not have an abnormal concentration of troponin T (i.e., not >0.1 μg/L). Also among the 110 non-AMI patients, 22 did have an abnormal troponin T value, 18 of whom (82%) also had CK-MBmassincreased by >2.0 μg/L. In 20 of the 23 patients with an increase in CK-MBmass >2.0 μg/L, this increase was detected from the values for two samples collected at 5 and 12 h after onset of symptoms. In conclusion, using the critical difference for CK-MBmassdefined as an increase >2.0 μg/L detected myocardial damage in patients without AMI.