bluuebunny/crossref_metadata_2025_split huggingface dataset:
Coupled-Column Liquid Chromatographic Analysis of Catecholamines, Serotonin, and Metabolites in Human Urine
Authors: Panholzer Torsten J , Beyer Jürgen , Lichtwald Klaus 
Published: January 2020

Abstract
Acolumn-switching HPLC system was utilized for the simultaneous determination of epinephrine, norepinephrine, dopamine, serotonin, and their metabolites metanephrine, normetanephrine, 3,4-dihydroxyphenylacetic acid, homovanillic acid, and 5-hydroxyindoleacetic acid in human urine. The sample was injected directly onto a C18-alkyl-diol silica precolumn, which separated the analytes from matrix. The analytes were eluted from the precolumn onto the analytical column by the use of column-switching techniques and were then separated on the analytical column by means of ion-pair reversed-phase HPLC. The analytes were then oxidized to the corresponding quinones and converted into fluorescent derivatives by reaction with meso-1,2-diphenylethylenediamine.
Reverse Transcription-Competitive Multiplex PCR Improves Quantification of mRNA in Clinical Samples—Application to the Low Abundance CFTR mRNA
Authors: Loitsch Stefan M , Kippenberger Stefan , Dauletbaev Nurlan , Wagner Thomas OF , Bargon Joachim 
Published: January 2020

AbstractBackground: To monitor gene therapy, we wished to quantify cystic fibrosis transmembrane conductance regulator (CFTR) mRNA. We developed a PCR-based method to measure CFTR mRNA in clinical samples.Methods: Expression was determined by reverse transcription-competitive multiplex PCR (RCMP) for CFTR and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) transcripts, and for serial dilutions of two internal cDNA standards consisting of CFTR and GAPDH mutants containing short deletions. The RCMP used simultaneous amplification of the gene of interest with a reporter gene in one reaction tube. The expression of CFTR was calculated with reference to the amount of GAPDH to correct for variations in initial RNA loading.Results: Amplification of cDNAs derived from different amounts of RNA (1–4 μg) gave similar GAPDH/CFTR ratios, with a coefficient of variation (CV) below 7.5%. RCMP was applied on nasal and bronchial brushings and shows a high variability of CFTR expression in non-cystic fibrosis donors.Conclusion: This method is precise and reproducible and advantageous for use with limited amounts of tissue, such as from biopsies or from nasal or bronchial brushings.
A Two-Year Study of Microscopic Urinalysis Competency Using the Urinalysis-Review Computer Program
Authors: Astion Michael L , Kim Sara , Nelson Amanda , Henderson Paul J , Phillips Carla , Bien Claudia , Mandel Lynn , Orkand Adam R , Fine James S 
Published: January 2020

Abstract
Background: The microscopic examination of urine sediment is one of the most commonly performed microscope-based laboratory tests, but despite its widespread use, there has been no detailed study of the competency of medical technologists in performing this test. One reason for this is the lack of an effective competency assessment tool that can be applied uniformly across an institution.
Methods: This study describes the development and implementation of a computer program, Urinalysis-ReviewTM, which periodically tests competency in microscopic urinalysis and then summarizes individual and group test results. In this study, eight Urinalysis-Review exams were administered over 2 years to medical technologists (mean, 58 technologists per exam; range, 44–77) at our academic medical center. The eight exams contained 80 test questions, consisting of 72 structure identification questions and 8 quantification questions. The 72 structure questions required the identification of 134 urine sediment structures consisting of 63 examples of cells, 25 of casts, 18 of normal crystals, 8 of abnormal crystals, and 20 of organisms or artifacts.
Results: Overall, the medical technologists correctly identified 84% of cells, 72% of casts, 79% of normal crystals, 65% of abnormal crystals, and 81% of organisms and artifacts, and correctly answered 89% of the quantification questions. The results are probably a slight underestimate of competency because the images were analyzed without the knowledge of urine chemistry results.
Conclusions: The study shows the feasibility of using a computer program for competency assessment in the clinical laboratory. In addition, the study establishes baseline measurements of competency that other laboratories can use for comparison, and which we will use in future studies that measure the effect of continuing education efforts in microscopic urinalysis.
Four Common Mutations of the Cystathionine β-Synthase Gene Detected by Multiplex PCR and Matrix-assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry
Authors: Harksen Angela , Ueland Per Magne , Refsum Helga , Meyer Klaus 
Published: January 2020

Abstract
Background: A deficiency of cystathionine β-synthase (CBS) is the most frequent cause of homocystinuria. The effect of therapy is related to the underlying CBS genotype, which makes early diagnosis of this genetic defect important. Our aim was to develop a fast and reliable method based on matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry for the determination of common mutations of the CBS gene.
Methods: We used MALDI-TOF mass spectrometry to detect four common CBS mutations (G307S, T272M, I278T, and V320A). The method is based on multiplex PCR of exons 7, 8, and 9, followed by single nucleotide extension in the presence of dideoxy NTPs of four primers targeted at the separate mutation sites. The extension products, as well as the 3-hydroxypicolinic acid matrix, were incubated with cation-exchange beads to remove disturbing salt contaminants.
Results: The above-mentioned mutations were determined in samples from 12 homocystinuria patients. The MALDI-TOF spectra allowed unambiguous discrimination between primers and extension products (&gt;9 Da) in the mass range between 4500 and 7500 Da. No labeled primers or ddNTPs were required. The genotyping was verified by reference technique.
Conclusion: Our results demonstrate fast, simple, and unambiguous multiplex genotyping of four common CBS mutations by MALDI-TOF mass spectrometry.
Effect of the Ratio of Free to Total Prostate-specific Antigen on Interassay Variability in Proficiency Test Samples
Authors: Fox M Pat , Reilly Andrew A , Schneider Erasmus 
Published: January 2020

Abstract
Background: Up to sevenfold differences were observed between total prostate-specific antigen (PSA) methods for New York State Proficiency Test samples prepared with seminal fluid PSA in human female serum. Because the PSA was mainly in its free form under these conditions, we wanted to determine whether a defined mixture of free and complexed PSA would reduce the interassay differences.
Methods: We prepared a series of five solutions of 60 g/L bovine serum albumin with 10 μg/L total PSA consisting of varied proportions of free, noncomplexible PSA, and α1-antichymotrypsin (ACT)-complexed PSA from 0% to 100%. Two hundred seventy laboratories measured the total PSA in these samples, and 16 laboratories also analyzed the samples for free PSA. The results were used to calculate free/total PSA ratios.
Results: Interassay CVs for total PSA measurements were ∼7% at 10–15% free PSA but became gradually larger as the free/total PSA ratio increased. Measured free-PSA concentrations were similar within each sample (mean CV, 12%), and the results were relatively independent of the proportion of free PSA in the samples. Twofold discrepancies between actual and expected ratios were observed with some methods at 100% free PSA and to a lesser degree at 30% free PSA. At 100% free PSA, the relatively higher total-PSA values measured by nonequimolar methods yielded low free/total PSA ratios of 50–60%. In contrast, the lower total PSA values obtained by equimolar methods yielded ratios close to the expected 100%.
Conclusions: Preparing proficiency test samples with a 10:90 mixture of free, noncomplexible PSA:PSA-ACT is a viable alternative to the use of seminal fluid PSA. Furthermore, the method used to measure total PSA may have a substantial impact on the calculated proportion of free PSA and hence may have clinical relevance.
Measurement of Cardiac Natriuretic Hormones (Atrial Natriuretic Peptide, Brain Natriuretic Peptide, and Related Peptides) in Clinical Practice: The Need for a New Generation of Immunoassay Methods
Authors: Clerico Aldo , Del Ry Silvia , Giannessi Daniela 
Published: January 2020

Abstract
Background: Cardiac natriuretic hormones (CNHs) are a family of related peptides, including atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and other peptides derived from the N-terminal portion of the proANP and proBNP peptide chains. Assays for cardiac natriuretic peptides have been proposed to help assess clinical conditions associated with expanded fluid volume. In particular, the assays can be useful for distinguishing healthy subjects from patients in different stages of heart failure. Measurements of these hormones have also been considered for prognostic indicators of long-term survival in patients with heart failure and/or after acute myocardial infarction. The different CNHs differ in their production/secretion patterns and have different clearance rates. Furthermore, there are numerous proposed assay configurations for each of these hormones, and it is not clear which assay provides the best pathophysiological and/or clinical information.
Approach: Here we review recent studies concerning the competitive (such as RIA, enzyme immunoassay, or luminescence immunoassay) and noncompetitive immunoassays (such as two-site IRMA, ELISA, or immunoluminometric assay) for the different cardiac natriuretic peptides to compare the analytical characteristics and clinical relevance of assays for the different CNHs and the different assay formats.
Content: Developing sensitive, precise, and accurate immunoassays for cardiac natriuretic peptides has been difficult because of their low concentrations (on average, ∼3–6 pmol/L) in healthy subjects and because of their structural, metabolic, and physiological characteristics. Competitive assays have historically suffered from lack of sensitivity and specificity for the biologically active peptides. These usually require tedious extraction procedures prior to analysis. Recently, immunometric assays have been developed that have improved sensitivity and specificity; it appears these will be the methods of choice.
Summary: To date, there is no consensus on the best assay procedure of cardiac natriuretic peptides. To facilitate widespread propagation of determination of these hormones in routine clinical practice, it will be necessary to study the new generation of noncompetitive immunometric methods that are less time-consuming and more sensitive and specific. Although several studies suggest that BNP exhibits better clinical utility than the other CNHs, more studies examining multiple CNHs in the same cohorts of patients will be necessary.
Genotypes and Phenotypes for Apolipoprotein E and Alzheimer Disease in the Honolulu-Asia Aging Study
Authors: Kardaun Jan W P F , White Lon , Resnick Helaine E , Petrovitch Helen , Marcovina Santica M , Saunders Ann M , Foley Dan J , Havlik Richard J 
Published: January 2020

AbstractBackground: The utility of apolipoprotein E (ApoE) type as an indicator of genetic susceptibility to Alzheimer disease (AD) depends on the reliability of typing. Although ApoE protein isoform phenotyping is generally assumed equivalent to genotyping from DNA, phenotype-genotype differences have been reported.Methods: ApoE genotype and phenotype results were examined for 3564 older (ages 71–93 years) Japanese-American male participants of the Honolulu-Asia Aging Study, an ongoing population-based study of aging and dementia.Results: Both methods demonstrated similar associations of ApoE type with AD: a direct association with ApoE4 and a less dramatic inverse association ApoE2. Advanced age did not appear to influence the ApoE4-AD association. The association with AD among ApoE4 homozygotes [odds ratio (OR) = 14.7] was higher than expected based on an observed OR of 2.0 in heterozygotes. Phenotype-genotype nonconcordance was more frequent for ApoE2 than for ApoE4. The ApoE2 phenotype occurred at a frequency of 7.9% vs a genotype frequency of 4.9%, corresponding to a probability of 56% that an individual with ApoE2 phenotype had the same genotype.Conclusions: Whereas E4 and E2 phenotypes and genotypes were comparably associated with AD, neither method would be expected to substantially improve the efficiency of case finding in the context of population screening beyond prediction based on age and education. Nonconcordance of phenotype and genotype was substantial for E2 and modest for E4 in this population. The ApoE4-AD association was independent of age.
Plasma Nitric Oxide Concentrations and Nitric Oxide Synthase Gene Polymorphisms in Coronary Artery Disease
Authors: Yoon Yeomin , Song Junghan , Hong Seung H o , Kim Jin Q 
Published: January 2020

AbstractBackground: Plasma NOx (nitrate and nitrite) is a stable end product of the vasodilator NO. Several polymorphisms in the endothelial constitutive NO synthase (ecNOS) gene have been reported, including the 4a/4b VNTR polymorphism in intron 4, the E298D mutation in exon 7, and the G10-T polymorphism in intron 23. The aims of this study were to examine plasma NOx in patients with coronary artery disease (CAD) and to assess the association between plasma NOx concentrations and the three ecNOS gene polymorphisms.Methods: Plasma NOx was measured in samples from 128 healthy controls and from 110 CAD patients at least 2 months after myocardial infarction. Three genetic polymorphisms that are known or have been suggested to be associated with plasma NOx concentration were also analyzed by PCR-restriction fragment length polymorphism.Results: Median plasma NOx was significantly higher (P &lt;0.001) in CAD patients (95.9 μmol/L) than in controls (73.8 μmol/L). Furthermore, the median plasma NOx was significantly higher (P &lt;0.001) in hypertensive CAD patients (116.0 μmol/L) than in controls and normotensive CAD patients (86.0 μmol/L). The G-allele frequency of the G10-T polymorphism in intron 23 was significantly higher in CAD patients than in controls. Other polymorphisms showed no differences in allelic frequencies among the control and CAD groups. In controls, individuals with the E298D mutation in exon 7 (136.1 μmol/L) showed significantly higher (P = 0.001) median plasma NOx than those without this mutation (64.5 μmol/L).Conclusions: Plasma NOx was higher in hypertensive CAD patients than in normotensive CAD patients and controls. The E298D polymorphism of the ecNOS gene was associated with increased plasma NOx. Further study is needed to understand the gene expression and enzyme activity of ecNOS and their association with genotypes.
Comparison of Capillary Electrophoresis with HPLC for Diagnosis of Factitious Hypoglycemia
Authors: Paroni Rita , Comuzzi Barbara , Arcelloni Cinzia , Brocco Stefano , de Kreutzenberg Saula , Tiengo Antonio , Ciucci Alessandra , Beck-Peccoz Paolo , Genovese Stefano 
Published: January 2020

Abstract
Background: The diagnosis of “factitious hypoglycemia” is essentially based on the disclosure of hypoglycemic agents in blood or urine. The aim of this study was to evaluate the performance of capillary electrophoresis (CE) as a quantitative method for determination of chlorpropamide, tolbutamide, glipizide, gliclazide, and glibenclamide in serum.
Methods: Serum samples (1 mL), with internal standard added, were purified by solid-phase extraction on OASISTM HLB cartridges (Waters), dried under reduced pressure, and reconstituted with 30–60 μL of acetonitrile:H2O. Analysis was carried out by micellar electrokinetic capillary chromatography in 5 mmol/L borate, 5 mmol/L phosphate, 75 mmol/L sodium cholate, pH 8.5, containing 25 mL/L methanol. Separation was accomplished in a 20 cm × 50 μm (i.d.) silica capillary at 25 °C and a constant voltage of +10 kV. Pharmacokinetics of gliclazide (80-mg tablet) in a diabetic patient were assayed by both HPLC and CE. Two hypoglycemic patients positive by HPLC analysis for unreported gliclazide and tolbutamide overdose were also screened by CE.
Results: Separation of six drugs (including the internal standard) was accomplished in 5 min plus 5 min rinsing. The between-day CV of the ratio of the areas of the sulfonylurea drugs to internal standard was &lt;1% (n = 10). Linearity (r2 ≥0.998) and recovery (≥80%) were good for all sulfonylurea drugs tested. Pharmacokinetic curves for gliclazide by CE and HPLC were superimposable. CE analysis confirmed the HPLC diagnosis of surreptitious abuse of gliclazide and tolbutamide.
Conclusion: CE is a useful tool in the clinical chemistry and toxicology laboratory for drug monitoring and pharmacokinetic investigations.
Agreement among Four Homocysteine Assays and Results in Patients with Coronary Atherosclerosis and Controls
Authors: Yu Harry H , Joubran Rana , Asmi Muhamad , Law Terence , Spencer Anthony , Jouma Muhidien , Rifai Nader 
Published: January 2020

Abstract
Background: Hyperhomocysteinemia has been associated with coronary atherosclerosis in many, but not all, prospective and retrospective studies. Some on these inconsistencies may be attributed to methodological variabilities.
Methods: In the present study, three newly commercially available assays and one in-house HPLC assay for total homocysteine (tHcy) were utilized in 99 subjects with angiographically documented atherosclerosis and in 91 community controls matched by age, gender, and smoking history. The in-house assay, a modified Fortin and Genest HPLC method, was compared with the Bio-Rad HPLC assay, the Abbott IMx® fluorescence polarization immunoassay, and a Bio-Rad enzyme-linked immunoassay (EIA) microtiter method.
Results: Correlation coefficient values between the in-house HPLC assay and the Bio-Rad HPLC, the Abbott IMx, and the Bio-Rad EIA assays were 0.95, 0.96 and 0.90, respectively. Although tHcy concentrations were higher in cases compared with controls by all four methods, the difference reached statistical significance only with the in-house HPLC procedure (median, 13.5 ± 6.7 μmol/L in cases vs 10.9 ± 4.8 μmol/L in controls; P &lt;0.01, adjusting for covariates), where it was an independent predictor of case or control status, along with hypertension, total cholesterol, and triglycerides. The tHcy distributions in cases and controls demonstrated significant overlap. The number of atherosclerotic major coronary vessels was associated with significantly higher tHcy (P &lt;0.01 for trend) in all four methods.
Conclusions: The three commercial assays for tHcy differed in analytical and clinical performance. Analytically, the Abbott IMx method showed the best comparability with the in-house assay, but clinically, the three commercial methods were similar and did not distinguish cases from controls.
History of Clinical Chemistry in a Children’s Hospital (1914–1964)
Authors: Meites Samuel 
Published: January 2020

AbstractThe historical development of a charitable children’s hospital and the evolution of its clinical laboratory are presented. With the appearance of practical quantitative blood chemistry tests in the period between the two World Wars, applications to pediatrics were hampered by the need for ultramicro procedures then unavailable and for improved skin-puncture blood sampling. World War II brought economic demands that forced the hospital to privatize its beds and to charge fee-for-services. In turn, this brought added income, allowing the hiring or subsidizing of a professional staff, including the clinical chemist. The development of ultramicro blood chemistry followed, along with improved skin-puncture technology.
The Costs of Disease
Authors: Young Donald S , Sachais Bruce S , Jefferies Leigh C 
Published: January 2020

Abstract
Background: To date there have been no studies identifying and comparing the component costs to treat a large number of diseases for hospitalized inpatients.
Methods: Hospital costs were analyzed for 486 diagnosis-related groups (DRGs) relating to &gt;1.3 million patient discharges from 60 University Hospital members of the University HealthSystems Consortium. For each DRG, length of stay, total cost, and key cost components were analyzed, including accommodation, intensive care, and surgery.
Results: In general, total costs of diseases classified as surgical exceeded those classified as medical. Diseases involving organ transplantation typically cost more than other diseases. However, within the studied population, the two DRGs accounting for most total healthcare dollars were percutaneous cardiovascular procedures and management of neonates with immaturity or respiratory failure.
Conclusions: Considering six key cost components, as well as disease complexity and length of stay, the best predictors of total costs for medical conditions were the length of stay and accommodation (housing, meals, nursing services) costs, whereas for surgical conditions, the best predictor of total costs was laboratory costs. This analysis may be used within an individual institution to identify surgical or medical diagnoses with total or component costs at variance with the group mean. A hospital may focus its cost reduction efforts to make decisions to expand, alter, or eliminate particular clinical programs based on comparison of its own total and component costs with those from other hospitals in the database.
Vitamin E and Coronary Heart Disease in Tunisians
Authors: Feki Moncef , Souissi Malek , Mokhtar Elyes , Hsairi Mohamed , Kaabachi Naziha , Antebi Helena , Alcindor Louis Gérald , Mechmeche Rachid , Mebazaa Abderraouf 
Published: January 2020

AbstractBackground: Vitamin E (VE) is thought to be effective in preventing atherosclerosis. However, to date no consistent relationship has been identified between VE and coronary heart disease (CHD). This study was designed to assess the degree of association between VE and CHD in a sample of the Tunisian population.Methods: Sixty-two angiographically confirmed coronary atherosclerotic patients and 65 age- and sex-matched controls were included. VE was measured in plasma and in the LDL fraction by HPLC. Cholesterol, triglycerides, and phospholipids were measured by enzymatic methods.Results: A trend toward a meaningful decrease of plasma VE was observed in affected patients compared with controls (P = 0.06). VE concentrations standardized for cholesterol and lipid concentrations were significantly lower (P &lt;0.02) in coronary patients than in controls (4.35 ± 1.03 vs 4.82 ± 1.23 mmol/mol for cholesterol-adjusted VE and 2.35 ± 0.56 vs 2.66 ± 0.65 mmol/mol for lipid-adjusted VE, respectively). In the LDL fraction, only cholesterol-standardized VE was significantly lower in cases than controls (3.84 ± 1.13 vs 4.41 ± 1.16 mmol/mol). This association between VE and CHD remained unchanged independent of age, sex, smoking habit, hypertension, and diabetes. In CHD patients, lower lipid-adjusted VE was associated with enhanced LDL susceptibility to oxidation but without alteration of the serum fatty acid profile.Conclusions: These results support the hypothesis that VE plays a role in preventing atherosclerosis.