bluuebunny/crossref_metadata_2025_split huggingface dataset:
Error-compensating kinetic method for enzymatic determination of DNAs
Authors: Lim K B , Pardue H L 
Published: January 2020

Abstract
We describe the adaptation and evaluation of an error-compensating method for kinetic determinations of deoxyribonucleic acids (DNAs). The DNA is first reacted with ethidium bromide to produce a fluorescent intercalation complex. Subsequent treatment of the complex with DNase catalyzes hydrolysis of the DNA, causing a time-dependent decrease in fluorescence, which is monitored. A model for two-component parallel first-order processes is fit to the decay curve to predict the total change in fluorescence expected if the process were monitored to equilibrium. The predicted change in fluorescence response varies linearly with DNA concentration with an intercept corresponding to 0.13 mg/L DNA. Results by the predictive method are 47-, 58-, and 250-fold less dependent on DNase activity, temperature, and ethidium bromide concentration, respectively, than are results for an initial-rate method utilizing the same data. Moreover, the predictive method yields a significantly wider linear range than the initial-rate method, and is much less affected by blank fluorescence and RNA interference than is an equilibrium method based on the reaction of DNA with ethidium bromide alone.
Revised structure of a delta-aminolevulinic acid derivative
Authors: Kajiwara M , Hara K , Takatori K , Matsumoto K 
Published: January 2020

Abstract
The structure of the fluorescent derivative formed in the method of Okayama et al. (Clin Chem 1990; 36:1494-7) for determining delta-aminolevulinic acid (ALA) concentrations was reinvestigated after esterification. The molecular ion peak at m/z 303.1473 corresponded to the molecular formula of C17H21NO4 (calcd 303.1470). The infrared spectrum showed the presence of carbonyl and carboxyl groups. This compound contained two acetyl groups, two methyl groups, and one methoxycarbonylethyl group, as revealed by 1H and 13C nuclear magnetic resonance and 13C-1H shift-correlated spectroscopy. Experiments with correlation spectroscopy via long-range coupling indicated that the main skeleton is 3H-pyrrolizine. The relative arrangement of functional groups was determined by means of nuclear Overhauser effect difference experiments. We were led to the conclusion that the methyl ester of the derivative is 2,6-diacetyl-1,5-dimethyl-7-(2-methoxycarbonylethyl)-3H-pyrrolizine. This structure was unequivocally confirmed by x-ray analysis; therefore, the structure of the derivative itself is 2,6-diacetyl-1,5-dimethyl-7-(2-carboxyethyl)-3H-pyrrolizine.
Multianalyte assay system developed for drugs of abuse
Authors: Parsons R G , Kowal R , LeBlond D , Yue V T , Neargarder L , Bond L , Garcia D , Slater D , Rogers P 
Published: January 2020

Abstract
A simple, 10-min immunoassay system has been developed that simultaneously screens for five different classes of drugs of abuse in a urine sample. This system tests for amphetamines, cannabinoids, cocaine metabolites, opiates, and phencyclidine, and each assay has a specific preset cutoff concentration. Accuracy is &gt; 99% for reporting positive or negative results for samples with 200% or 50%, respectively, of the cutoff concentrations of the drugs. Tests of a panel of 96 compounds yielded only three cases of nonspecific reactivity (at a drug concentration of 100 mg/L). Another panel of 12 compounds that could normally be found in urine samples was also evaluated and no interferences were observed. Concordance was &gt; 95% between this system and the comparable automated immunoassays for detecting drugs of abuse. Greater than 98% of GC/MS-confirmed positive samples gave positive results with this assay system.
Diagnosis of peroxisomal disorders by analysis of phytanic and pristanic acids in stored blood spots collected at neonatal screening
Authors: ten Brink H J , van den Heuvel C M , Christensen E , Largillière C , Jakobs C 
Published: January 2020

Abstract
Concentrations of phytanic acid and pristanic acid were measured in stored dried blood spots collected at neonatal screening from patients with peroxisomal disorders, and compared with concentrations in control blood spots. In blood spots from two patients with Zellweger syndrome both phytanic acid and pristanic acid concentrations were increased but their concentration ratio was normal. In the blood spot from a patient with rhizomelic chondrodysplasia punctata, the concentration of phytanic acid was increased, whereas pristanic acid was within the control range, resulting in a low pristanic acid/phytanic acid ratio. In the blood spot from a patient with X-linked adrenoleukodystrophy, the concentrations of the acids and their ratio were normal. These findings are consistent with results for these acids in plasma from such patients. Measurement of phytanic acid and pristanic acid and their ratios in stored dried blood collected at neonatal screening can therefore be used in the diagnosis of peroxisomal disorders, especially for those cases in which, owing to early death of the patient, no other material is available for biochemical investigations.
Solid-phase extraction technique for gas-chromatographic profiling of acylcarnitines
Authors: Van Bocxlaer J F , De Leenheer A P 
Published: January 2020

Abstract
We present a simple, new clean-up method for the gas-chromatographic profiling analysis of acylcarnitines. The use of a solid-phase, cation-exchange extraction combined with gas-chromatographic separation, based on the derivatization into acyloxylactones by Lowes and Rose (Analyst 1990;115:511-6), allows a selective and sensitive screening for acylcarnitines in urine. As such, a quantitative approach was developed for differential evaluation of acylcarnitines for detection of inborn errors of metabolism; the evaluation is both fast and routinely applicable in any biochemical laboratory. We validate the analysis method for acylcarnitines of various chain-lengths and present examples of its application to urine samples from diseased patients. We give special attention to the medium-chain acylcarnitines because of their association with medium-chain acylCoA dehydrogenase deficiency. Finally, the quantitative nature of the analysis allows evaluation of the acylcarnitine excretion over time.
A transcriptionally amplified DNA probe assay with ligatable probes and immunochemical detection
Authors: Carpenter W R , Schutzbank T E , Tevere V J , Tocyloski K R , Dattagupta N , Yeung K K 
Published: January 2020

Abstract
Transcriptionally amplified DNA probes are valuable tools in the development of sensitive nucleic acid-based diagnostic assays. Here we describe a model assay using a novel oligonucleotide hairpin probe that encodes a T7 RNA polymerase promoter. The hairpin probe and an adjacently hybridizing biotinylated capture probe were hybridized to target DNA and the duplex was captured onto streptavidin-coated magnetic particles. After ligation of the immobilized probes, which served to maintain specificity, the hairpin probe was transcribed by T7 RNA polymerase. The amplified RNA product was hybridized to the capture probe and bound to the streptavidin-coated magnetic particles. The immobilized heteroduplex was detected with an antibody-alkaline phosphatase conjugate specific for DNA:RNA hybrids, and the chemiluminescent substrate adamantyl-1,2-dioxetane phenyl phosphate. Ten attomoles of target DNA could be detected in a background of 5 micrograms of unrelated DNA. The chemiluminescent immunoassay was as sensitive as radioactive detection of specific product after gel electrophoresis.
Homogeneous detection of nucleic acids by transient-state polarized fluorescence
Authors: Devlin R , Studholme R M , Dandliker W B , Fahy E , Blumeyer K , Ghosh S S 
Published: January 2020

Abstract
We describe a transient-state polarized fluorescence-based method for detecting nucleic acids. An active ester of the phthalocyanine dye La Jolla Blue was coupled to an oligonucleotide containing an amino group at its 5' end, and the conjugate was purified by HPLC chromatography. We monitored the hybridization characteristics of the conjugate with complementary oligonucleotides and RNA as targets by transient-state polarized fluorescence measurements. The method was comparable in sensitivity to isotopic and nonisotopic heterogeneous detection systems and was capable of detecting 1 fmol of a 382-base-long RNA transcript from human immunodeficiency virus type (HIV-1) generated in a self-sustained sequence replication (3SR) reaction.
Molecular engineering: applications to the clinical laboratory
Authors: Hamilton R G 
Published: January 2020

Abstract
Advances in cellular and molecular biology methods have led to the molecular engineering of novel human biomolecules, some of which have been successfully applied to the documentation of clinical laboratory assays. Here I describe the use of engineered chimeric antibodies in the clinical immunology laboratory in three principal applications: (a) as reference proteins to document the specificity of clinical assay reagents, be used as reagent-grade purified antigens, and facilitate the epitope mapping of antibody reagents; (b) as calibration proteins to assign mass/volume estimates to proposed antibody standards; and (c) as interference proteins to study the effects of naturally occurring autoantibodies on the accuracy and sensitivity of current clinical assays. The model recombinant proteins used for these illustrations are chimeric antibodies with a defined V-region specificity for one of two haptens (nitrophenyl or dansyl) and C-region domains covering a spectrum of human isotypes. I also describe a panel of mutant human IgG1-4 anti-dansyl chimeric antibodies that have been genetically engineered with swapped, deleted, or point-mutated wild-type C-region exons and used as specialized reagents for mapping the epitopes to which clinically used human IgG-specific monoclonal antibodies bind. Finally, the use of a recombinant human IgG1 anti-human IgE Fc chimeric antibody to simulate human IgG anti-IgE autoantibody interference in assays of total serum IgE is investigated.
65 Clinical depression among post- acute coronary syndrome patients: A prospective single tertiary centre analysis
Authors: Leong L , Mahmood Zuhdi A S , Abdul Hafidz M I 
Published: January 2020

Abstract

Background
Clinical depression is a known consequence of acute coronary syndrome (ACS). It is also known to carry an adverse outcome among these patients. Despite the availability of validated tools for screening of depression in acute coronary syndrome patients, depression is still significantly under-recognized and undertreated in patients with acute coronary syndrome.

Purpose
To investigate the prevalence of depression in post-ACS patients and the factors associated with it.

Methods
Prospective cohort study conducted on 95 ACS patients (26 female, 69 male) admitted to our cardiology ward University. Data collected with consent from patients through electronic medical record and Patient Health Questionnaire (PHQ-9), Medical Adherence Questionnaire(MAQ). Depression outcome at 30-day was obtained from hospital records and via phone call to the patient. Data analyzed using SPSS 24.0. Chi-square test was used for comparison of categorical variables and independent t-test and Mann-Whitney U tests were used for comparison of continuous variables. Binary logistic regression was used to determine the independent associated factors for depression after adjusted with significant demographic variables and clinical characteristics. The strength of this association was presented in odds ratio (OR) and 95% confidence interval (CI). The significance level adopted was 0.05.

Results
Mean age of the study population is 60 years old. 72.6% were male and 27.4% female. Symptoms of depression (mild to severe) were present in 88.4% of patients at baseline. Among the depressed patients, 22.6% of the cases were found to have for severe depression, 14.3% moderately-severe depressed, 15.5% moderately depressed, 27.4% for mildly depressed and 20.2% for minimally depressed. Depression at 30-day post discharge is more likely in women, diabetics and dialysis patients (p= 0.024, p &lt; 0.001, p= 0.008 respectively). There was no difference in depression among ethnicity. Patients with baseline moderate to severe depression are more likely to have moderate to severe depression at 30 days (p &lt; 0.001). Patients with low adherence to medications at 30 days reported moderate to severe depression at 30 days (p = 0.007). Baseline depression is the strongest predictor of 30-days depression. An increase in one unit of PHQ-9 baseline score increases the risk of developing severe depression after 30 days by 29%. There is no difference in terms of mortality between patients with significant depression and those without.

Conclusions
Clinical depression is prevalent in our post-ACS patients. Associated factors are female gender, diabetics and dialysis patients. Depression at baseline predicts clinical depression at 30-days post discharge and is associated with low adherence to their medications. Thus we should actively screen for depression among ACS patients in order to administer appropriate treatment.
148 Inappropriate elevation of angiopoietin-2 relative to hemodynamic stability is associated with bleeding events in patients with continuous flow mechanical circulatory support
Authors: Nakamura M , Hori M , Nakagaito M , Kinugawa K 
Published: January 2020

Abstract

Funding Acknowledgements
none

Background
Elevated angiopoietin-2 (Ang-2) has been attributable to a potential cause of gastrointestinal bleeding among patients with continuous flow (CF) mechanical circulatory support (MCS) in the US, but Ang-2 levels have not been examined in the Japanese MCS patients who are likely to have less gastrointestinal bleeding.

Methods
We enrolled 18 patients (64 ± 16y; LVEF 26 ± 9%) with advanced heart failure (HF) who received temporary or durable MCS, or were given intravenous inotropes from August 2018 to January 2019. Serum Ang-2 and plasma BNP were simultaneously measured at various treatment status. The relationship between each value and any spontaneous bleeding events requiring hemostasis or blood transfusion was examined.

Results
103 blood samples were collected and divided into 2 groups. One was the CF group, which consisted of samples from patients under CF-MCS (Impella, ECMO, Jarvik2000, HeartMateII), and the others were assigned to the Non-CF group. Ang-2 levels had a positive correlation with BNP levels (r = 0.33, p = 0.0006, Fig). CF-MCS efficiently lowered BNP levels (353 ± 125 in CF vs 1053 ± 119 in Non-CF, pg/mL, p &lt; 0.0001), but Ang-2 levels relative to BNP levels were significantly higher in the CF group as shown in the Figure (Ang-2/log10(BNP) ratio: 3.77 ± 0.30 in CF vs 2.43 ± 0.29 in Non-CF, p = 0.0017). Bleeding events were remarkably frequent when Ang-2/log10(BNP)&gt;3.17 (77.8%) than ≦3.17 (22.2%, p = 0.0002).

Conclusions
High Ang-2 level is normally a marker for hemodynamic compromise, but CF-MCS may stimulate Ang-2 production despite hemodynamic stabilization. Most of spontaneous bleeding events accompany inappropriately high Ang-2 relative to BNP level among Japanese patients with advanced HF.
Abstract 148 Figure. Correlation between Ang-2 and BNP
299 The prevalence and role of SCN10A variants in Han Chinese patients with Brugada syndrome: the SADS-TW BrS registry
Authors: Chen C-Y , Liu Y-B , Lu T-P , Yu Q-Y , Lin L-Y , Yu C-C , Makita N , Ishikawa T , Lai L-P , Hwang J-J , Yeh S-F , Lin J-L , Juang J-M , Horie M , Antzelevitch C 
Published: January 2020

Abstract

On Behalf
SADS-TW BrS registry

Background
Brugada syndrome (BrS) is an inheritable arrhythmic disease responsible for sudden cardiac death. Information on the prevalence and role of SCN10A variants in BrS is limited and equivocal.

Purpose
We aimed to investigate the prevalence and role of SCN10A variants in BrS in Han Chinese.

Methods
From 2000 to 2017, we prospectively and consecutively enrolled 176 unrelated BrS patients from the Han Chinese population in Taiwan (the SADS-TW BrS registry). Thirty-four BrS-related genes were screened by next-generation sequencing, using Taiwan Biobank as the population reference. The pathogenicity was evaluated by literature review and in silico analyses, including the SKAT-O algorithm.

Results
The SKAT-O algorithm showed that rare variants of SCN10A, but not common variants, were significantly different between BrS patients and healthy controls in the additive and dominant models (p-value &lt;0.001), suggesting that rare SCN10A variants may play a role in BrS. Six likely pathogenic SCN10A variants were found in 6 patients and were compared to 25 pathogenic or likely pathogenic SCN5A variants found in 29 patients. The patients with likely pathogenic SCN10A variants tended to exhibit sudden death in older age and have a shorter QRS interval than those carrying pathogenic or likely pathogenic SCN5A variants or no variants in either gene (p = 0.06, 0.07, respectively). Collectively, the prevalence of likely pathogenic SCN10A variants was 3.4% in Han Chinese patients with BrS in Taiwan.

Conclusions
SCN10A likely pathogenic variants were present in 3.4% of Han Chinese BrS patients. Rare SCN10A variants may play a role in BrS, and may have impact on clinical and electrocardiographic manifestations.
Table 1. Patient Nucleotide Amino acid TWB gnomAD_EA REVEL CADD PHRED SIFT Polyphen-2 GERP++ 1 c.5789A &gt; T p.D1930V 0.001318 0.0008700 0.479 24.5 Damaging Possibly damaging 4.22 2 c.2341G &gt; A p.G781R 0 0.00005301 0.866 33 Damaging Probably damaging 4.83 3 c.5587C &gt; T p.R1863W 0.000502 0 0.832 27.8 Damaging Probably damaging 1.97 4 c.2161C &gt; T p.P721S 0.000989 0.0009016 0.933 28.5 Damaging Probably damaging 4.19 5 c.3749G &gt; A p.R1250Q 0 0 0.907 31 Damaging Probably damaging 4.23 6 c.1825A &gt; T p.R609W 0.000659 0.0001591 0.811 32 Damaging Probably damaging 4.28 Clinical and predicted functional characteristics of 6 likely pathogenic SCN10A variants. EA = East Asian; GERP = Genomic Evolutionary Rate Profiling; TWB = Taiwan Biobank. Transcript: NM_006514.3.
Abstract 299 Figure. Location of the SCN10A variants
P7 The impact of coronary calcification on diagnostic performance of workstation CT derived fractional flow reserve - a multicentre experience
Authors: Ihdayhid A R , Motoyama S , Fujimoto S , Isa M , Nerlekar N , Kato E , Miyajima K , Comella A , Kamo Y , Sarai M , Kawai H , Arakita K , Hislop-Jambrich J , Cameron J , Ko B 
Published: January 2020

Abstract

Background
On-site workstation based computed tomography derived fractional flow reserve (CT-FFR) is an emerging method to assess the vessel specific ischaemia in coronary artery disease (CAD). The impact of coronary calcification on its diagnostic performance is unknown.

Purpose
To evaluate the impact of coronary calcification on the diagnostic performance of reduced-order CT-FFR at detecting vessel specific ischaemia.

Methods
This is a retrospective pooled analysis of 141 patients with suspected CAD enrolled from 3 global centres who underwent CT-coronary angiography (CTA), onsite CT-FFR and invasive FFR. Coronary calcification was assessed by Agatston score (AS). The diagnostic performance of CT-FFR (≤0.8) and CTA (≥50%) in evaluation of vessel specific ischaemia (FFR ≤ 0.8) was assessed across AS quartiles (Q1-4). A comparison of diagnostic performance of the low to mid AS (Q1 to Q3) versus high AS (Q4) was performed.

Results
Mean age and median AS was 65.8 ± 9.9 and 327.3 (interquartile range = 78.5 – 798.1). Diagnostic accuracy, sensitivity and specificity of CT-FFR for low-mid AS (0-798) and high AS (799-4019) were 77.4% vs 82.9%; 78.9% vs 94.7%; 68.8% vs 76.5% respectively with no statistical difference between the two groups. The AUC for ischaemia of CT-FFR in low to mid AS was comparable with AUC in the high AS (0.76 [95% CI: 0.66-0.86] vs 0.84 [0.69-0.99]; P = 0.397). The AUC for ischemia for CT-FFR in both low to mid AS and high AS was significantly higher than for CTA (0.76 [0.66-0.86] vs 0.57 [0.50-0.64]; P = 0.003 and 0.84 [0.69-0.99] vs 0.48 [0.38-0.57]; P &lt; 0.001 respectively).

Conclusion
On-site workstation CT-FFR demonstrated consistently high diagnostic performance in patients with high AS. Its diagnostic performance was superior when compared with significant stenosis assessment on CTA across all spectrum of Agatston scores.
P9 Novel use of CHA2DS2VASC score to select patients to undergo repeat atrial fibrillation screening
Authors: Sun W , Yan B P Y 
Published: January 2020

Abstract

Background
We have previously demonstrated unselected screening for atrial fibrillation (AF) in patients ≥65 years old in an out-patient setting yielded 1-2% new AF each time screen-negative patients underwent repeated screening at 12 to 18 month interval. Selection criteria to identify high-risk patients for repeated AF screening may be more efficient than repeat screening on all patients.

Aims
This study aimed to validate CHA2DS2VASC score as a predictive model to select target population for repeat AF screening.

Methods
17,745 consecutive patients underwent 24,363 index AF screening (26.9% patients underwent repeated screening) using a handheld single-lead ECG (AliveCor) from Dec 2014 to Dec 2017 (NCT02409654). Adverse clinical outcomes to be predicted included (i) new AF detection by repeated screening; (ii) new AF clinically diagnosed during follow-up and (ii) ischemic stroke/transient ischemic attack (TIA) during follow-up. Performance evaluation and validation of CHA2DS2VASC score as a prediction model was based on 15,732 subjects, 35,643 person-years of follow-up and 765 outcomes. Internal validation was conducted by method of k-fold cross-validation (k = n = 15,732, i.e., Leave-One-Out cross-validation). Performance measures included c-index for discriminatory ability and decision curve analysis for clinical utility. Risk groups were defined as ≤1, 2-3, or ≥4 for CHA2DS2VASC scores. Calibration was assessed by comparing proportions of actual observed events.

Results
CHA2DS2VASC scores achieved acceptable discrimination with c-index of 0.762 (95%CI: 0.746-0.777) for derivation and 0.703 for cross-validation. Decision curve analysis showed the use of CHA2DS2VASC to select patients for rescreening was superior to rescreening all or no patients in terms of net benefit across all reasonable threshold probability (Figure 1, left). Predicted and observed probabilities of adverse clinical outcomes progressively increased with increasing CHA2DS2VASC score (Figure 1, right): 0.7% outcome events in low-risk group (CHA2DS2VASC ≤1, predicted prob. ≤0.86%), 3.5% intermediate-risk group (CHA2DS2VASC 2-3, predicted prob. 2.62%-4.43%) and 11.3% in high-risk group (CHA2DS2VASC ≥4, predicted prob. ≥8.50%). The odds ratio for outcome events were 4.88 (95%CI: 3.43-6.96) for intermediate-versus-low risk group, and 17.37 (95%CI: 12.36-24.42) for high-versus-low risk group.

Conclusion
Repeat AF screening on high-risk population may be more efficient than rescreening all screen-negative individuals. CHA2DS2VASC scores may be used as a selection tool to identify high-risk patients to undergo repeat AF screening.
Abstract P9 Figure 1