bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of hemodialysis on total antioxidant capacity and serum antioxidants in patients with chronic renal failure
Authors: Jackson P , Loughrey C M , Lightbody J H , McNamee P T , Young I S 
Published: January 2020

Abstract
Cardiovascular disease is the major cause of mortality in patients receiving hemodialysis for chronic renal failure. Increased lipid peroxidation and depletion of chain-breaking antioxidants may contribute to increased risk of atherosclerosis. We have therefore assessed the effect of a single episode of hemodialysis on antioxidant status in 22 patients and control subjects. Overall, total antioxidant capacity of serum was increased in dialysis patients, but there was a marked reduction after hemodialysis [571 +/- 31 vs 342 +/- 22 mumol/L Trolox (water-soluble vitamin E analog) equivalents, P &lt; 0.001]. The increase in total antioxidant capacity before hemodialysis was almost entirely due to relatively high serum urate. Among individual chain-breaking antioxidants, dialysis led to a decrease in urate (398 +/- 15 vs 136 +/- 12 mumol/L, P &lt; 0.001), ascorbate (10.5 +/- 1.7 vs 5.9 +/- 1.0 mumol/L, P &lt; 0.01), and lipid-corrected tocopherol (4.70 +/- 0.56 vs 4.26 +/- 0.39 mumol/mmol cholesterol, P &lt; 0.05). Protein thiol groups increased after dialysis (328 +/- 16 vs 422 +/- 22 mumol/L, P &lt; 0.001), whereas albumin remained unchanged (40.1 +/- 1.1 vs 41.0 +/- 1.6 g/L, not significant). Although total antioxidant capacity of serum is increased in hemodialysis patients, depletion of key chain-breaking antioxidants may lead to accelerated atherogenesis.
Assay of plasma testosterone during the first six months of life: importance of chromatographic purification of steroids
Authors: Fuqua J S , Sher E S , Migeon C J , Berkovitz G D 
Published: January 2020

Abstract
Determination of the plasma concentration of testosterone (T) is important in evaluating infants born with ambiguous genitalia and micropenis, and several commercially available kits provide a direct assay of T in unextracted plasma. Using plasma samples obtained from 36 subjects &lt; 6 months old, we compared the concentration of plasma T measured by RIA after extraction and purification by column chromatography with the T concentration measured in a direct assay. When aliquots of samples were purified before RIA, the concentration of T was markedly lower than in the direct assay. In the first 3 weeks postpartum, results of the direct assay were 3.8-fold greater than those obtained after purification. This difference decreased over time, and by age 2 months there was fairly good agreement between the two methods. These data indicate that some direct assays of plasma T are inappropriate during the first 2 months postpartum.
Interpretation of serial measurements of international normalized ratio for prothrombin times in monitoring oral anticoagulant therapy
Authors: Lassen J F , Kjeldsen J , Antonsen S , Hyltoft Petersen P , Brandslund I 
Published: January 2020

Abstract
Despite careful monitoring of oral anticoagulant treatment (OAT), some international normalized ratio (INR) for prothrombin time values will fall outside the therapeutic range. Considerable changes in serial INR results from OAT patients may be caused by random fluctuation alone, and, for statistical reasons, a fraction of the INR values will fall outside therapeutic range and interfere with dose adjustments. On the basis of therapeutic intervals and statistical evaluation of reference changes, we suggest and discuss an alternative method for interpretation of serial INR measurements. Retrospective evaluation of serial measurements of INR from OAT patients revealed an "overshooting" phenomenon. When a dose was adjusted on the basis of insignificant change in INR value, the subsequent INR value generally fell in the opposite direction. If a further change of dose was initiated because of the new INR value, a similar course in the opposite direction was observed. This "ping-pong" effect renders patients in a fluctuating state of anticoagulation and may introduce increased risk of complications. The suggested method provides an objective criterion for dose adjustments in OAT, which should reduce patients' risk.
The changing role of the clinical laboratory scientist: coming out of the basement
Authors: Wilding P 
Published: January 2020

Abstract
The position of clinical chemistry within the discipline of laboratory medicine is firmly established. As a result, pathologists, chemists, and scientists have been attracted to an emerging field full of promise and expectations. For most, the expectations of a rewarding career and growth of the discipline have been met. However, in a climate where factors such as "capitation" and "managed care" influence every facet of healthcare, many are reviewing their expectations and wondering whether the 21st century will bring the same promise enjoyed by the pioneers in the 20th century. In the future, laboratory scientists must align their expectations to the demands for new technologies, medical practices, and healthcare systems that will require justification for all activities, expense, and personnel. To succeed in this new environment, the clinical chemist will need excellent managerial skills, an understanding of how to articulate the benefits of technologies and laboratory tests, and a willingness to embark on a career of unceasing education.
Metaanalysis in clinical chemistry: validation of cardiac troponin T as a marker for ischemic heart diseases
Authors: Wu A H , Lane P L 
Published: January 2020

Abstract
Metaanalysis is a method that incorporates the pooling of previously published results to produce more statistically significant results. We used metaanalysis to examine the role of a new cardiac marker, cardiac troponin T (cTnT), in patients with ischemic heart disease. Metaanalysis of six articles and one abstract on cTnT showed that this marker was just as sensitive as creatine kinase MB isoenzyme (CK-MB) for the retrospective diagnosis of acute myocardial infarction (AMI) 12-48 h after onset but less specific. Most of these articles showed that cTnT was increased in non-AMI patients with unstable angina pectoris. In a metaanalysis of four papers, two abstracts, a letter, and an unpublished manuscript, we examined the prognostic role of cTnT in non-AMI cardiac patients. For an unfavorable endpoint defined as cardiac death, AMI, or the need for coronary artery revascularization, the results demonstrated that abnormal concentrations of cTnT were associated with a higher risk for a poor outcome than were normal concentrations of cTnT. We also compared cTnT with CK-MB for risk stratification. Metaanalysis will become an increasingly important tool for evaluating new tests as they become available.
Improving laboratory testing: can we get physicians to focus on outcome?
Authors: Wong E T 
Published: January 2020

Abstract
Managed care is changing the financing of healthcare and replacing open-ended reimbursement with fixed pricing schemes. Clinical laboratory tests will remain an important part of medical practice because laboratory information is essential for diagnosis and management of patients. The relative role of the hospital-based clinical laboratory, however, remains to be determined because healthcare organizations are reevaluating their services and attempting to drive down costs through reducing unit costs, decreasing utilization of services, and improving patient outcomes. The challenge for the clinical laboratory in managed care is to achieve appropriate utilization of laboratory tests so that clinical outcomes are optimized. The clinical laboratory at this medical center has used a number of approaches to improve utilization of thyroid function tests, isoenzyme tests for myocardial infarction, beta-human chorionic gonadotropin tests, and stat laboratory services for the emergency department. These experiences suggest that the laboratory can contribute to optimizing utilization of laboratory tests. This goal will require mutual cooperation of both the clinician and the clinical laboratory physician and (or) scientist.
Multivariate receiver-operating characteristic curve analysis: prostate cancer screening as an example
Authors: Shultz E K 
Published: January 2020

Abstract
The evolution of test performance analysis should include the long-term costs and benefits associated with testing. Evolutionary laboratory techniques to achieve this include introduction of a new methodological technique, a multivariate extension to a current analytical technique, receiver-operating characteristic (ROC) curve analysis (MultiROC analysis). This extension to ROC methodology allows the comparison of composite test rules in a format similar to that of ROC curves. Statistical properties, guidelines for use, and a detailed example are described. MultiROC is used in the outcomes analysis of the value of screening for prostate cancer. The effect of age and different test decision thresholds are examined in an extension of a previously published outcomes analysis. The results indicate that the variations in test performances caused by these components are important in assigning a final cost:benefit ratio of screening for prostate cancer.
Homogeneous immunoassay of whole-blood samples
Authors: Merenbloom B K , Oberhardt B J 
Published: January 2020

Abstract
Proof of principle has been shown for a rapid, quantitative, homogeneous immunoassay capable of analyzing whole-blood samples. The assay was performed with test cards and a small instrument designed for use at the point of care. The immunoassay has an immunological "front end" combined with a coagulation cascade chemistry "back end" and is made possible by combining two patented technologies: (a) a serine protease inhibitor [Porter and Bruhnke, Photochem and Photobiol 1990; 51(1):37] and (b) paramagnetic iron oxide particles (PIOP) in a mixture of buffers and coagulation assay components supplied as a dry film in a test-card reaction chamber [Oberhardt et al., Clin Chem 1991;37:520]. A model steric-hindrance immunoassay based on these technologies was established for the measurement of biotin. The calibration curve was developed by measuring plasma samples supplemented with biotin. The reagents were inhibited biotinylated thrombin, anti-biotin monoclonal antibody, and PIOP.
Analytical and clinical performance goals for testing autoantibodies to thyroperoxidase, thyroglobulin, and thyrotropin receptor
Authors: Feldt-Rasmussen U 
Published: January 2020

Abstract
Methods for measuring thyroid autoantibodies--to thyroperoxidase (TPOAb), thyroglobulin (TgAb), and thyrotropin receptor (TRAb)--have improved over the last decade, but increasingly, accurate and sensitive methods are needed for identifying patients with autoimmune thyroid diseases and individuals at high risk for onset of thyroid autoimmunity. With the increased quality requirements for these methods, it becomes more important to look at the functional sensitivities and precision profiles of the various methods. International standardization in this field is also needed. Because most sera containing human thyroid autoantibodies display a variety of antigen-specific immunoglobulins of different classes and subclasses with different affinity and avidity in their epitope reaction, investigators must decide whether the autoantibodies should be quantified in terms of immunoglobulin content, antigen/epitope reactivity, or binding capacity. Until these problems are solved, the best means for standardization are the Medical Research Council calibrators for TPOAb and TgAb, whereas no standardization exists for TRAb.
Identification and quantification of hemoglobins A, F, S, and C by automated chromatography
Authors: Papadea C , Cate J C 
Published: January 2020

Abstract
The Bio-Rad Variant Hemoglobin Testing System is an automated HPLC analyzer marketed with a Beta-thalassemia Short Program to quantify hemoglobins (Hbs) F and A2 and assist in detecting Hbs A, S, C, D, and E. We evaluated this system to replace several traditional methods for Hb in our hospital laboratory. Analytical performance relevant to quantifying Hbs A, S, C, and F was assessed with blood samples obtained from our local patient population. Studies of precision (CVs &lt; 3%) and analytical limits (% of total Hb) of Hbs A (2-86%), F (1-89%), S (5-90%), and C (3-92%) demonstrated results comparable with or exceeding those of traditional methods. Results for patients' samples (n) for Hbs A (107), F (157), S (128), and C (27) correlated well (r &gt; 0.93) with results by traditional methods. The satisfactory performance and efficiency led us to implement this system for routine quantification of clinically significant Hbs.
Marked interference of hyperglycemia in measurements of mean (red) cell volume by Technicon H analyzers
Authors: van Duijnhoven H L , Treskes M 
Published: January 2020

Abstract
Severe hyperglycemia can result in falsely high results for mean cell (erythrocyte) volume (MCV), which will also cause false results for erythrocyte indices calculated on the basis of MCV. Falsely high MCV results were obtained with the Technicon H1 and H2 analyzers and (to a lesser extent) with the Coulter T660. The H analyzers were more susceptible to this interference than was the Coulter T660. This difference in sensitivity of MCV to hyperglycemia can be explained by the use of sodium dodecyl sulfate in the Technicon erythrocyte diluent and by differences in incubation times. In severe hyperglycemia, results for MCV, mean cell hemoglobin concentration, and hematocrit obtained from electronic cell counters, especially Technicon H systems, are unreliable.
Inhibition of Na,K-ATPase by oleandrin and oleandrigenin, and their detection by digoxin immunoassays
Authors: Jortani S A , Helm R A , Valdes R 
Published: January 2020

Abstract
Ingestion of oleander plant, containing the cardiac glycoside oleandrin, has been reported to induce fatal poisonings. Derivatives of oleandrin are structurally similar to digoxin. We investigated the cross-reactivities of oleandrin and its aglycone metabolite, oleandrigenin, in several commercially available digoxin immunoassays; assessed their ability to inhibit Na,K-ATPase catalytic activity; and measured their binding to proteins in serum. As assayed with ACS:180, Stratus, RIA, On-Line, and TDx digoxin assays, oleandrin at 100 micromol/L in digoxin-free serum gave apparent digoxin values of 0, 0.83, 2.24, 2.37, and 5.34 nmol/L, respectively, whereas oleandrigenin at that concentration gave results of 0, 0.52, 0.77, 4.94, and 1.40 nmol/L. Study of Na,K-ATPase inhibition showed IC50 values (micromol/L) of 0.22 for ouabain, 0.62 for oleandrin, 1.23 for oleandrigenin, and 2.69 for digoxin. At 25 degrees C, 96% of oleandrin and 48% of oleandrigenin were bound to serum proteins. Because detection of oleandrin and oleandrigenin by digoxin immunoassays is variable between assays as well as between congeners, assessment of cross-reactivity is warranted for each assay. The inhibition of Na,K-ATPase by oleandrin and oleandrigenin confirms that they likely exert their toxic effects through inhibition of sodium pump activity. In cases of digitalis-like poisoning with suspicion of oleander ingestion, a combination of digoxin immunoassays may be useful to effectively rule out the presence of oleander.
Performance evaluation of automated immunoassays on the Technicon Immuno 1 system
Authors: Letellier M , Lévesque A , Daigle F , Grant A 
Published: January 2020

Abstract
We performed an immunoassay evaluation for various analytes on a fully automated random-access analyzer, the Technicon Immuno 1 system from Bayer Corp. This system involves latex agglutination, magnetic separation sandwich, and magnetic separation competitive immunoassay configurations. The evaluated analytes were thyrotropin (TSH), triiodothyronine, thyroxine, free thyroxine, follitropin, lutropin, prolactin, beta subunit of human chorionic gonadotropin, cortisol, ferritin, alpha-fetoprotein, carcinoembryonic antigen, and prostate-specific antigen. We tested the assay precision, linearity, and correlation with comparison methods for these analytes. The functional sensitivity of the TSH assay and the sample-to-sample carryover were also studied. Excellent results were obtained for within-run and between-day precision studies, with most assays showing within-run CVs &lt;4% and between-day CVs &lt;6%. The linearity for all assays was acceptable and the correlation between Immuno 1 assays and comparison methods showed satisfactory results. The functional sensitivity of the TSH assay was estimated at 0.04 mU/L. No sample-to-sample carryover was detected.
Effect of salt intake on excretion of endogenous ouabain-like substance, measured by RIA
Authors: Semra Y K , Butt A N , Swaminathan R 
Published: January 2020

Abstract
Recent studies suggest that ouabain or a ouabain-like substance (OLS) may be present endogenously in humans. We developed a RIA for ouabain with antisera raised in goat against ouabain conjugated to keyhole limpet hemocyanin and ovalbumin. The antiserum was of high antibody titer (200,000) and was specific for ouabain, with little cross-reactivity with common steroids and structurally related compounds such as ouabagenin (4%), strophanthidin (4%), and dihydroouabain (2%). The RIA had a working range of 0.06-2.0 nmol/L, and the intra- and interassay CV was 6.5% at a concentration of 1.7 nmol/L. With this assay the effect of salt loading on urinary excretion of OLS was examined in 10 healthy volunteers (ages 18-22 years) who increased their salt intake (sodium) for 5 days and reduced it for the next 5 days. Urine was collected and OLS concentration was measured by RIA after solid-phase extraction with a Bond Elut C18 column. Excretion of OLS and sodium were maximal on day 5 and lowest on days 9 and 10. Urine excretion of OLS on day 5 (2.66 +/- 1.22 nmol/24 h) was significantly higher (P &lt; 0.0001) than on day 10 (1.47 +/- 0.69 nmol/24 h). We conclude that (a) the assay developed has sufficient sensitivity and specificity to detect endogenous OLS present in biological fluids, and (b) salt intake increases the excretion of OLS.
Spectrophotometric determination of urinary iodine by flow-injection analysis with on-line catalytic digestion
Authors: Yaping Z , Dongxing Y , Jixiang C , Tianshiu L , Huiqin C 
Published: January 2020

Abstract
A flow-injection technique involving on-line catalytic digestion and spectrophotometric detection has been developed for the determination of iodine in urine. After urine samples are digested by KMnO4-K2Cr2O7-H2SO4 solution, the iodine in the urine catalyzes the reaction of As(III) with Ce(IV). The remaining Ce(IV) is then reacted with brucine and the product is detected with a spectrophotometer at 480 nm. With this technique, we obtained a detection limit for urinary iodine of 0.039 mumol/L, and the linear range was 0.039-7.88 mumol/L with a CV &lt; 3%. Analytical recovery ranged between 92% and 104% (mean 99%). The sampling frequency of the flow-injection technique was 70/h. We applied the method to measure the iodine concentration in a freeze-dried urine reference sample and in collected urine samples, and compared the results with those obtained by the accepted alkaline ashing technique. The proposed technique has the advantages of being simple, rapid, precise, accurate, and sensitive. It can be used to assess iodine-deficient populations as well as those receiving treatment.
Assay of plasma homocysteine: light sensitivity of the fluorescent 7-benzo-2-oxa-1, 3-diazole-4-sulfonic acid derivative, and use of appropriate calibrators
Authors: Dudman N P , Guo X W , Crooks R , Xie L , Silberberg J S 
Published: January 2020

Abstract
The recognition of homocysteine as a vascular risk factor has led to increased clinical interest in assaying plasma homocysteine concentrations. Our aim was to improve the reliability of a widely used assay based on HPLC of the fluorescent 7-benzo-2-oxa-1, 3-diazole-4-sulfonic acid (SBD) derivative. We found that SBD derivatives of homocysteine, cysteine, and N-acetylhomocysteine were highly unstable in light but essentially stable in the dark for several hours at either 0 degree C or 25 degrees C. As our primary calibrator, we chose homocystine added to human serum for more consistent results than homocysteine or homocystine in an aqueous buffer. N-acetylcysteine was effective as an internal recovery standard. We observed a previously unreported peak with a prolonged elution time in some plasma samples from subjects who had ingested methionine. Our findings suggest improvements in this and other assay procedures for plasma homocysteine.
Cerebrospinal fluid and plasma distribution of myo-inositol and other polyols in Alzheimer disease
Authors: Shetty H U , Holloway H W , Schapiro M B 
Published: January 2020

Abstract
Previous studies suggest the presence of increased concentrations of cerebral myo-inositol in Alzheimer disease (AD). To characterize this abnormality further, we quantified myo-inositol and several other polyols in cerebrospinal fluid (CSF) and plasma from 10 AD subjects and 10 healthy age-matched controls by using a gas chromatographic-mass spectrometric technique. The mean CSF concentration and CSF/plasma concentration ratio of myo-inositol in AD were not significantly different from those determined in control subjects. Also, concentration profiles of other polyols were not significantly altered in AD. CSF and plasma myo-inositol concentrations were correlated in control subjects but not in AD subjects. However, a significant correlation between CSF and plasma 1,5-anhydrosorbitol (a polyol internal control) concentrations observed in control subjects was retained in AD subjects.
Heteroduplex generator in analysis of Rh blood group alleles
Authors: Stoerker J , Hurwitz C , Rose N C , Silberstein L E , Highsmith W E 
Published: January 2020

Abstract
We describe the use of heteroduplex analysis to enhance the resolution of different rhesus-derived (Rh) isotypes. Heteroduplex analysis of different domains of the Rh D and Rh CE loci can be performed to diagnose a variety of blood group incompatibilities. One application of this technique is the ability to test for fetal-maternal blood group incompatibilities during pregnancy. Several new serotype-specific sequence variations were discovered in the mapping of the Rh locus, and used in the construction of artificial heteroduplex generators (HGs). HGs facilitate the resolution of the Rh isotypes by electrophoretic methods.
Sandwich ELISA for glutathione S-transferase Alpha 1-1: plasma concentrations in controls and in patients with gastrointestinal disorders
Authors: Mulder T P , Peters W H , Court D A , Jansen J B 
Published: January 2020

Abstract
Class Alpha glutathione S-transferases (GST-Alpha) are found in high concentrations in human liver. Increased plasma concentrations of GSTA1-1, the most abundant isoform of GST-Alpha, are a very sensitive marker for hepatocellular leakage. A sandwich-type ELISA was developed, based on a monoclonal antibody specific for human GSTA1-1 and a polyclonal rabbit anti-human GST-Alpha antiserum. The assay is specific for human GSTA1-1, and has a detection limit of 0.04 micrograms/L. The distribution of plasma GSTA1-1 concentrations in 350 blood donors was nearly normalized by logarithmic transformation and an upper normal reference concentration of 5.9 micrograms/L was calculated. Men had significantly higher plasma GSTA1-1 concentrations than women (P &lt;0.0001). In women, but not in men, a significant increase was noted with age (P &lt;0.05). In patients with inflammatory bowel disease (n= 210), gastrointestinal tumors (n= 70), irritable bowel disease (n= 36), or chronic pancreatitis (n= 12), plasma GSTA1-1 concentrations were similar to those of controls. In contrast, plasma GSTA1-1 concentrations were increased to a similar extent as alanine aminotransferase activities in patients with liver disorders (n= 37).