bluuebunny/crossref_metadata_2025_split huggingface dataset:
Automated measurement of mouse apolipoprotein B: convenient screening tool for mouse models of atherosclerosis
Authors: Levine Daniel M , Williams Kevin Jon 
Published: January 2020

AbstractAlthough mice are commonly used for studies of atherosclerosis, investigators have had no convenient way to quantify apolipoprotein (apo) B, the major protein of atherogenic lipoproteins, in this model. We now report an automated immunoturbidimetric assay for mouse apo B with an NCCLS imprecision study CV &lt;5%. Added hemoglobin up to 50 g/L did not interfere with the assay, nor did one freeze–thaw cycle of serum samples. Assay linearity extends to apo B concentrations of 325 mg/L. We have used the assay to determine serum apo B concentrations under several atherogenic conditions, including the apo E “knock-out” genotype and treatment with a high-cholesterol diet. Our assay can be used to survey inbred mouse strains for variants in apo B concentration or regulation. Moreover, the mouse can now be used as a convenient small-animal model to screen compounds that may lower apo B concentrations.
Plasma malondialdehyde as biomarker for oxidative stress: reference interval and effects of life-style factors
Authors: Nielsen Flemming , Mikkelsen Bo Borg , Nielsen Jesper Bo , Andersen Helle Raun , Grandjean Philippe 
Published: January 2020

Abstract
Malondialdehyde (MDA) is one of the most frequently used indicators of lipid peroxidation. To generate reliable reference intervals for plasma malondialdehyde (P-MDA), a reference sample group was established in Funen, Denmark. The group consisted of 213 individuals (107 men, 106 women), ages 20–79 years. P-MDA was measured in EDTA-treated plasma after derivatization by thiobarbituric acid (TBA) and separation on HPLC. UV detection was performed at 532 nm. A reference interval was calculated as recommended by IFCC with REFVAL 3.42. The estimated reference limits (0.025 and 0.975 fractals) for the group were 0.36 and 1.24 μmol/L. The data were analyzed for gender- and age-related differences. Analysis of variance showed no interaction between gender and age, but separate analyses showed an independent effect of gender (P = 0.03), but not of age (P = 0.11). Daily smokers had a slightly higher average concentration of P-MDA than nonsmokers (P = 0.05), and P-MDA correlated with daily exposure to cigarette smoke (r = 0.162; P = 0.03). A positive correlation was also demonstrated between P-MDA and weekly alcohol consumption (r = 0.153; P = 0.03). Within-subject and day-to-day variations of P-MDA indicated that the potential of P-MDA as a biomarker for individuals is questionable. However, on a group basis, the present data support that P-MDA may be a potential biomarker for oxidative stress.
Mistakes in a stat laboratory: types and frequency
Authors: Plebani Mario , Carraro Paolo 
Published: January 2020

Abstract
Application of Total Quality Management concepts to laboratory testing requires that the total process, including preanalytical and postanalytical phases, be managed so as to reduce or, ideally, eliminate all defects within the process itself. Indeed a “mistake” can be defined as any defect during the entire testing process, from ordering tests to reporting results. We evaluated the frequency and types of mistakes found in the “stat” section of the Department of Laboratory Medicine of the University-Hospital of Padova by monitoring four different departments (internal medicine, nephrology, surgery, and intensive care unit) for 3 months. Among a total of 40 490 analyses, we identified 189 laboratory mistakes, a relative frequency of 0.47%. The distribution of mistakes was: preanalytical 68.2%, analytical 13.3%, and postanalytical 18.5%. Most of the laboratory mistakes (74%) did not affect patients’ outcome. However, in 37 patients (19%), laboratory mistakes were associated with further inappropriate investigations, thus resulting in an unjustifiable increase in costs. Moreover, in 12 patients (6.4%) laboratory mistakes were associated with inappropriate care or inappropriate modification of therapy. The promotion of quality control and continuous improvement of the total testing process, including pre- and postanalytical phases, seems to be a prerequisite for an effective laboratory service.
Determination of urinary free cortisol by HPLC
Authors: Turpeinen Ursula , Markkanen Helene , Välimäki Matti , Stenman Ulf-Håkan 
Published: January 2020

Abstract
We here report a reversed-phase HPLC method for the determination of free cortisol in human urine, using methylprednisolone as the internal standard. Before chromatography, samples were extracted with a C18 solid-phase extraction column and the steroids were separated on a LiChrospher 100 C18 column with a mobile phase of methanol/acetonitrile/water (43/3/54 by vol). Linearity, precision, and accuracy of the method were established. The detection limit was 10 pmol of cortisol, and total CVs were &lt;8%. With various solid-phase extraction columns the recovery of cortisol was 36–97%; recovery of the internal standard was 43–85%. Study of interference by 6 other steroids and metabolites and 24 drugs showed that carbamazepine and digoxin partly overlapped with cortisol, but this interference could be reduced by modification of the mobile phase. The HPLC method was compared with an RIA and an automated immunoassay method. The results obtained by HPLC averaged 40% of the RIA values.
Application of the Department of Health and Human Services proposed waived status requirements for in vitro diagnostic testing devices: case study
Authors: Ehrmeyer Sharon S , Laessig Ronald H 
Published: January 2020

Abstract
The CLIA’88 classified all clinical laboratory testing as waived, moderate, or high complexity. The eight original waived tests were characterized as simple, accurate, error-free, risk-free, and suitable for home use by nonlaboratory professionals. The subjective nature of the classification process was challenged immediately. The Clinical Laboratory Improvement Advisory Committee asked the CDC and the Health Care Financing Administration to develop objective criteria that included assessment of performance by field-test and in-house data. We examined the efficacy of the CDC protocol with empirical data from the HemoCue B-Hemoglobin Test System® submission, to assess operator competency, intra-/interoperator and between-site imprecision, and accuracy. Non-laboratory-trained operators demonstrated 2–3% imprecision (40–200 g/L). Accuracy studies yielded a slope of 1.01, an intercept of 3.53 g/L, and r of 1.00 (52–230 g/L). Results met the protocol’s Tonks’ criterion for imprecision (less than one-fourth of the reference range).
Proficiency testing of creatine kinase and creatine kinase-2: the experience of the Ontario Laboratory Proficiency Testing Program
Authors: Henderson A Ralph , Krishnan Suba , Webb Sharon , Cheung C Mark , Nazir Darius J , Richardson Harold 
Published: January 2020

Abstract
The Ontario Laboratory Proficiency Testing Program has regularly monitored the analytical performance of total creatine kinase (CK) (≈230 participants) and CK isoenzyme-2 (CK-MB) (≈160 participants) throughout the entire province. Consistently, a wide dispersion of results has been observed not only between different analyzer systems but also among identical analyzers. Accordingly, the results of the last three proficiency surveys for these analytes were examined statistically to establish both the extent of these variations and the range of values reported for the male upper reference ranges. The results of many of the analyzer systems were significantly different from each other, as were many of the reference ranges. This unsatisfactory situation may only be remedied by the use of reference materials as shown by others. The consequences of these findings also effect the reliability of epidemiological surveys such as the WHO MONICA Project (Circulation 1994;90:583–612), which monitors deaths due to heart disease and includes cardiac enzyme results in its criteria.
Rebound increase of plasminogen activator inhibitor type 1 after cessation of thrombolytic treatment for acute myocardial infarction is independent of type of plasminogen activator used
Authors: Genser Norbert , Lechleitner Peter , Maier Josef , Dienstl Franz , Artner-Dworzak Erika , Puschendorf Bernd , Mair Johannes 
Published: January 2020

Abstract
Plasma concentrations of tissue-type plasminogen activator (t-PA), plasminogen activator inhibitor type 1 (PAI-1), and D-dimer were investigated in 50 patients treated intravenously for acute myocardial infarction with either streptokinase (n = 23), urokinase (n = 17), or recombinant t-PA (rt-PA, n = 10). The fibrinolytic variables were measured by enzyme immunoassay on admission; 1, 2, 4, 6, 8, 12, and 24 h later; and then daily until day 7 after admission. In each subgroup of patients treated with different thrombolytic agents, PAI-1 increased significantly (P &lt;0.01) ∼3 h after cessation of thrombolytic therapy. PAI-1 peak concentrations did not differ significantly (P = 0.82) among these three subgroups. t-PA and D-dimer did not differ significantly (P &gt;0.14) among subgroups except for higher t-PA in the rt-PA group attributable to detection of the therapeutically administered exogenous rt-PA by the t-PA assay. Our findings demonstrate a marked PAI-1 increase after thrombolytic therapy for acute myocardial infarction, which seems to be a common, drug-independent antifibrinolytic rebound phenomenon in response to thrombolytic treatment.
High-pressure-mediated dissociation of immune complexes demonstrated in model systems
Authors: Cheung Charles Y , Green David J , Litt Gerald J , Laugharn James A 
Published: January 2020

Abstract
The use of pressure to disrupt immune complexes was demonstrated in two model systems: prostate-specific antigen (PSA) and anti-PSA antibody; and epiglycanin, a mucin glycoprotein, and an antibody specific to that protein. Dissociation of the anti-PSA antibody from the immobilized PSA antigen was observed when pressures of 415 MPa and 550 MPa (1 MPa ∼144 psi) were applied at room temperature (∼21 °C). Application of pressures ranging from 140 MPa to 550 MPa resulted in dissociation of antibody from epiglycanin. In both cases, the rebinding of dissociated antibody to immobilized antigen indicated that the effect of high pressure on the binding of the immune complexes was reversible. These findings suggest that application of high hydrostatic pressure has the potential to be used to significantly improve the sensitivity and specificity of clinical assays.
Antibody interference in thyroid assays: a potential for clinical misinformation
Authors: Després Normand , Grant Andrew M 
Published: January 2020

Abstract
Measurements of thyrotropin and of total and free thyroxine and triiodothyronine are widely used diagnostic methods for thyroid function evaluation. However, some serum samples will demonstrate a nonspecific binding with assay reagents that can interfere with the measurement of these hormones. Several recent case reports have described the presence of such interferences resulting in reported abnormal concentrations of thyroid hormones inconsistent with the patient’s thyroid state. Circulating thyroid hormone autoantibodies, described in thyroid and nonthyroid disorders, are an important class of interference factor and can bind to hormone tracers used in various immunoassays. Two additional categories of interfering antibodies may particularly interfere within two-site immunoassays for thyrotropin. These include heterophile antibodies, especially human anti-mouse antibodies, and rheumatoid factors, which can cause interferences by immunoglobulin aggregation and (or) cross-linking of both capture and signal antibodies. Here we review the nature of these disturbances; their occurrence, prevalence, and detection; and the clinical consequences of the failure to recognize such interference.
Comparison of different analytical methods for assessing total antioxidant capacity of human serum
Authors: Cao Guohua , Prior Ronald L 
Published: January 2020

Abstract
Three assays were compared for the determination of total antioxidant capacity in human serum: the oxygen radical absorbance capacity (ORAC) assay, the Randox Trolox-equivalent antioxidant capacity (Randox-TEAC) assay, and the ferric reducing ability (FRAP) assay. There was a weak but significant linear correlation between serum ORAC and serum FRAP. There was no correlation either between serum ORAC and serum TEAC or between serum FRAP and serum TEAC. The effect of dilution on the serum TEAC value and the use of inhibition percentage at a fixed time, without considering the length of inhibition time in the quantitation of results, adversely affected the Randox-TEAC assay. The FRAP assay is simple and inexpensive but does not measure the SH-group-containing antioxidants. The ORAC assay has high specificity and responds to numerous antioxidants. By utilizing different extraction techniques in the ORAC assay, one can remove serum proteins and also make some gross differentiation between aqueous and lipid-soluble antioxidants. However, the ORAC assay requires ∼60 min more than the FRAP or Randox-TEAC assay to quantitate results.
Teaching the microscopic examination of urine sediment to second year medical students using the Urinalysis-Tutor computer program
Authors: Phillips Carla , Henderson Paul J , Mandel Lynn , Kim Sara , Schaad Doug , Cooper Mindy , Bien Claudia , Orkand Adam , Wener Mark H , Fine James S , Astion Michael L 
Published: January 2020

Abstract
The microscopic examination of urine sediment is a common diagnostic tool taught to medical students, medical technologists, and others. The urine microscopic exam is difficult to teach because supervised instruction and textbook-based teaching suffer from numerous drawbacks. Here, we describe Urinalysis-Tutor, a computer program that uses digitized microscope images and computer-based teaching techniques to systematically teach the urine microscopic exam. In addition, we report the results of a 2-year study that evaluated the effectiveness of the program in 314 second year medical students who were required to use the program. The program contained two, 20-question exams. In the first year of the study (1996), one of the exams was chosen as the pretest and the other as the posttest; the pretest had to be completed before the students viewed the contents of the program, and the posttest was taken after finishing the tutorial. In 1997, the order of the two exams was reversed. In 1996, 159 students completed the study. The mean pretest score was 34% (SD, 14%), the mean posttest score was 71% (SD, 13%), and the improvement was significant (P &lt;0.001, paired t-test). In 1997, 155 students participated. The mean pretest score was 41% (SD, 11%), the mean posttest score was 71% (SD, 13%), and the improvement was significant (P &lt;0.001, paired t-test). The study shows that Urinalysis-Tutor helps medical students learn to interpret the microscopic appearance of urine sediment and that it is feasible to implement this tutorial in a medical school class.
Useful laboratory tests for studying thrombogenesis in acute cardiac syndromes
Authors: Fareed Jawed , Hoppensteadt Debra A , Leya Fred , Iqbal Omer , Wolf Helmut , Bick Roger 
Published: January 2020

Abstract
We review laboratory tests that evaluate thrombogenesis during acute coronary syndromes. These tests have been found to be valuable research tools in more clearly understanding the pathophysiology of acute coronary syndromes. In particular, we describe tissue factor, tissue factor pathway inhibitor, prothrombin fragment 1.2, thrombin-antithrombin complex, fibrinopeptide A, tissue plasminogen activator (t-PA), plasminogen activator inhibitor-1 (PAI-1), t-PA-PAI complex, Bβ 15–42-related peptides, fibrinogen degradation products, fibrin degradation products, D-dimer, platelet factor 4, β-thromboglobulin, 5-hydroxytryptamine, thromboxane B2, prostacyclin, endothelin, angiotensin-converting enzyme, soluble thrombomodulin, C1-esterase inhibitor, anaphylotoxins C3a, C4a, and C5a, bradykinin, tumor necrosis factor, leukotriene C4, platelet activating factor, anti-phospholipid antibody, and von Willebrand factor. Some of these tests may prove to be useful in clinical diagnosis and management of acute coronary syndromes. Clinical outcome studies are needed to determine which tests may be cost effective and medically useful.
Simultaneous Serum Assays of Lipase and Interleukin-6 for Early Diagnosis and Prognosis of Acute Pancreatitis
Authors: Pezzilli Raffaele , Morselli-Labate Antonio Maria , Miniero Rita , Barakat Bahjat , Fiocchi Manuela , Cappelletti Onda 
Published: January 2020

AbstractBackground: There are no systems for the rapid diagnosis and prognosis of acute pancreatitis in the Emergency Department. Our aim was to evaluate whether the combined use of serum lipase and interleukin-6 or serum lipase and C-reactive protein is able to simultaneously establish both the diagnosis and the prognosis of acute pancreatitis.Methods: Eighty patients with acute abdomen were studied on admission to the Emergency Room. Forty patients had nonpancreatic acute abdomen, and 40 had acute pancreatitis (25 had mild acute pancreatitis and 15 had severe pancreatitis). Forty healthy subjects comparable for sex and age were also studied as controls. Lipase, interleukin-6, and C-reactive protein were determined on serum in all subjects.Results: Using lipase to discriminate between patients with nonpancreatic acute abdomen and patients with acute pancreatitis (cutoff values ranging from 419 to 520 U/L), one patient with acute pancreatitis was not identified correctly. To discriminate between patients with severe acute pancreatitis and those with mild pancreatitis in the remaining 39 patients, interleukin-6 (cutoff value, &lt;3.7 μg/L) had a sensitivity of 100% (15 of 15) and a specificity of 83% (20 of 24); 75 of 80 (94%) patients were classified correctly. C-reactive protein (cutoff values ranging from 6 to 7 mg/L) showed a lower prognostic efficiency than interleukin-6: sensitivity of 87% (13 of 15) and specificity of 46% (11 of 24). Sixty-four of 80 patients (80%) were classified correctly. The area under the ROC curve for interleukin-6 (0.911 ± 0.049) was significantly (P = 0.013) greater than that for C-reactive protein (0.685 ± 0.090).Conclusion: The combined use of serum lipase and interleukin-6 is useful in simultaneously establishing both the diagnosis and the prognosis of acute pancreatitis.
Plastic Microchip Electrophoresis for Analysis of PCR Products of Hepatitis C Virus
Authors: Chen Yu-Hung , Wang Wei-Chang , Young Kung-Chia , Chang Ting-Tsung , Chen Shu-Hui 
Published: January 2020

Abstract
Background: Electrophoresis on polymeric rather than glass microstructures is a promising separation method for analytical chemistry. Assays on such devices need to be explored to allow assessment of their utility for the clinical laboratory.
Methods: We compared capillary and plastic microchip electrophoresis for clinical post-PCR analysis of hepatitis C virus (HCV). For capillary electrophoresis (CE), we used a separation medium composed of 10 g/L hydroxypropyl methyl cellulose in Tris-borate-EDTA buffer and 10 μmol/L intercalating dye. For microchip electrophoresis, the HCV assay established on the fused silica tubing was transferred to the untreated polymethylmethacrylate microchip with minimum modifications.
Results: CE resolved the 145-bp amplicon of HCV in 15 min. The confidence interval of the migration time was &lt;3.2%. The same HCV amplicon was resolved by microchip electrophoresis in &lt;1.5 min with the confidence interval of the migration time &lt;1.3%.
Conclusion: The polymer microchip, with advantages that include fast processing time, simple operation, and disposable use, holds great potential for clinical analysis.
Single-Step Mutation Scanning of the 6-Pyruvoyltetrahydropterin Synthase Gene in Patients with Hyperphenylalaninemia
Authors: Romstad Anne , Guldberg Per , Blau Nenad , Güttler Flemming 
Published: January 2020

AbstractBackground: Deficiency of 6-pyruvoyltetrahydropterin synthase (PTPS) is a recessively inherited disorder that leads to depletion of 5,6,7,8-tetrahydrobiopterin, the obligatory cofactor for hydroxylation of phenylalanine, tyrosine, and tryptophan. A marker for neonatal detection of PTPS deficiency is hyperphenylalaninemia (HPA). Molecular analysis would provide a simple and reliable means for distinguishing PTPS deficiency from other potential causes of HPA.Methods: We developed a method based on PCR in combination with denaturing gradient gel electrophoresis (DGGE) that rapidly scans the six coding sequences and all splice sites of the PTPS gene (PTS) for mutations. This method was used to examine the status of the PTS gene in control samples with known PTS mutations and in five patients with PTPS deficiency.Results: Two features of the PTS gene posed particular problems in relation to DGGE analysis: the very high GC content of exon 1, and a 15-bp poly(dT) stretch in the acceptor splice site of intron 1. Both problems were solved by special design of amplification primers. PCR and DGGE conditions were adjusted to allow simultaneous analysis of all six regions of the PTS gene. Using this one-step approach, all control mutations were readily resolved. Among the five PTPS patients, four mutations were identified, including IVS1-3C→G, IVS2-7T→A, V57del, and V97M (289G→A). The IVS1-3C→G mutation was shown by reverse transcription-PCR analysis to produce multiple splice variants.Conclusions: We have established a fast and reliable screening method for detection of mutations and small deletions/insertions in the PTS gene. This method should be useful for rapid diagnosis of PTPS deficiency in newborns with HPA.
Rapid Diagnosis of Herpes Simplex Encephalitis Using Microchip Electrophoresis of PCR Products
Authors: Hofgärtner Wolfgang T , Hühmer Andreas FR , Landers James P , Kant Jeffrey A 
Published: January 2020

Abstract
Background: Herpes simplex virus (HSV) is the most common cause of acute sporadic encephalitis in the United States. PCR of DNA extracted from cerebrospinal fluid (CSF) allows for reliable diagnosis of herpes simplex encephalitis (HSE). A faster turnaround time for HSE testing would improve patient management and lead to better outcomes. The aims of this study, therefore, were to develop a microchip-based electrophoretic method for rapid detection of HSV PCR products, and to compare the performance characteristics of liquid hybridization/gel retardation as an established clinical PCR product detection method with the new microchip-based method.
Methods: The study examined archival DNA from 33 selected CSF specimens submitted for HSV PCR testing to the clinical laboratory. One aliquot of the HSV PCR product was analyzed by liquid hybridization/gel retardation analysis, and a second PCR aliquot was analyzed directly with a microchip capillary electrophoresis system using an instrument built in-house. PCR samples were introduced directly into the microchip without a desalting step by use of a novel fluidic interface. Channel surfaces on the glass microchip were silanized, followed by derivatization with polyvinylpyrrolidone.
Results: Of the 33 CSF specimens tested by liquid hybridization analysis of HSV PCR products, 10 tested positive for HSV DNA, 2 gave a weakly positive result, and 21 tested negative. Total analysis time for detection of HSV DNA by gel retardation assay was 18 h. Microchip electrophoresis provided identical results in &lt;110 s/sample, achieving 100% sensitivity and specificity compared with the established method.
Conclusions: Microchip-based electrophoresis can rapidly and accurately separate HSV PCR products, giving results identical to those obtained by liquid hybridization but with substantially decreased turnaround time. Clinical implementation of the new method will help to improve patient management and outcomes.