bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chemistry of the fructosamine assay: D-glucosone is the product of oxidation of Amadori compounds
Authors: Baker J R , Zyzak D V , Thorpe S R , Baynes J W 
Published: January 2020

Abstract
The chemistry of the fructosamine assay was studied by using the Amadori compound, N alpha-formyl-N epsilon-fructose-lysine (fFL), an analog of glycated lysine residues in protein. Previously (Clin Chem 1993;39:2460-5), we reported that free lysine was formed from fFL at 70% yield during incubation with alkaline nitroblue tetrazolium (NBT) under the conditions routinely used for the fructosamine assay (sodium carbonate buffer, pH 10.35 at 37 degrees C). Here, we show that D-glucosone is the primary carbohydrate oxidation product formed from Amadori compounds in the fructosamine assay. Glucosone, which decomposes under alkaline assay conditions with a half-life of &lt; 30 min, reaches a maximum concentration of approximately 50% of the initial fFL concentration after 10 min of incubation. Like fFL, glucosone reduces NBT to the purple monoformazan dye, but its decomposition is not accelerated by the presence of NBT. The dicarbonyl-trapping reagent, aminoguanidine, inhibits the fructosamine assay by approximately 25% when fFL is the substrate, but by nearly 100% with glucosone as substrate. Studies with serum samples from diabetics and nondiabetics indicate that glucosone formation does not have a significant effect on the clinical usefulness of the fructosamine assay; however, corrections for glucosone formation may be required when the assay is used for estimating the extent of glycation of proteins.
Evaluation of preanalytical variables associated with measurement of prothrombin fragment 1.2
Authors: Greenberg C S , Hursting M J , Macik B G , Ortel T L , Kane W H , Moore B M 
Published: January 2020

Abstract
We have used a monoclonal antibody-based ELISA for plasma prothrombin fragment 1.2 (F1.2) to establish appropriate sample collection and storage conditions for this biomarker of thrombin generation. F1.2 concentrations were not altered by exogenous factor Xa, thrombin, or thromboplastin if blood was collected by routine venipuncture into tubes containing heparin as anticoagulant (but not citrate, acid-citrate-dextrose, EDTA, or oxalate) and if plasma antithrombin III concentration was &gt; or = 30% of normal. Heparinized plasma F1.2 was stable for &gt; or = 8 h at 20-25 degrees C, and if premixed with a stabilizing reagent, for &gt; or = 4 years at -70 degrees C. Mean values for heparinized plasma F1.2 collected and stored by recommended procedures were increased in patients with thrombosis and conditions of increased thrombotic risk, and were sensitive to heparin and oral anticoagulant therapies. We conclude that plasma obtained by routine venipuncture into tubes with heparin as anticoagulant is an appropriate specimen for F1.2 measurements for most patients.
Immunoassay for quantifying type I collagen degradation products in urine evaluated
Authors: Bonde M , Qvist P , Fledelius C , Riis B J , Christiansen C 
Published: January 2020

Abstract
An enzyme-linked immunosorbent assay (ELISA) for measuring type I collagen degradation products in urine &lt; 3 h was evaluated. The measuring range was 0.5-10.5 mg/L with a detection limit of 0.2 mg/L. Within-run and total CVs were 5.3% and 6.6%, respectively. Analytical recovery averaged 100%. The mean (+/- SD) concentrations in urine samples from a healthy premenopausal population (n = 102) were 250 +/- 110 mg/mol creatinine (Cr). A group of healthy postmenopausal women (n = 410) gave a mean value of 416 +/- 189 mg/mol Cr. Values obtained in the ELISA correlated well (r = 0.83) to HPLC values for the established bone resorption marker deoxypyridinoline (n = 214), slightly better than the correlation to hydroxyproline measurements (r = 0.78, n = 421). We conclude that the assay described here presents a useful tool for further elucidating the importance of type I collagen degradation products in urine.
Assay of plasma oxalate with soluble oxalate oxidase
Authors: Petrarulo M , Cerelli E , Marangella M , Cosseddu D , Vitale C , Linari F 
Published: January 2020

Abstract
We use oxalate oxidase from barley seedlings for the colorimetric determination of oxalate in plasma. The oxalate is converted to hydrogen peroxide, which, in the presence of peroxidase, is detected by a Trinder-like chromogenic system. Optimization of the assay, including deproteinization and elimination of interferences from reducing substrates, is described. Ascorbate additions (200 mumol/L) did not affect oxalate concentration in plasma, even after long frozen storage. Mean analytical recovery of oxalate averaged 102% +/- 6.9%, imprecision (CV) at 2.0 mumol/L was 7.2%, and the lower limit of quantification (CV = 20%) was 0.6 mumol/L. Results correlated well with those by chromatography (r = 0.999, Sy/x = 0.29 mumol/L, n = 32, range for x, y = 0-140 mumol/L). Plasma oxalate concentrations measured in 32 healthy subjects ranged from 0.6 to 2.9 mumol/L (mean 1.28, SD 0.71 mumol/L), which agrees with those measurable by using indirect radioisotopic dilution methods. Patients with primary hyperoxaluria and chronic renal failure exhibited markedly greater plasma concentrations of oxalate.
Effect on sports drug tests of ingesting meat from steroid (methenolone)-treated livestock
Authors: Kicman A T , Cowan D A , Myhre L , Nilsson S , Tomten S , Oftebro H 
Published: January 2020

Abstract
Anabolic-androgenic steroids are widely misused in human sports and are also used as growth promoters in livestock. Athletes who consume meat containing such hormone residues may risk failing a sports drug test. Prompted by an athlete's defense case, we questioned whether the consumption of small livestock given doses of anabolic steroid, orally or intramuscularly, could generate positive results in samples tested by our analytical procedures. We analyzed urine from eight men who consumed chickens that had been either fed with methenolone acetate (1 mg/day) from day 0 to 21 or injected with methenolone heptanoate depot (1 mg/intramuscular injection) on days 0, 7, and 14 and slaughtered on day 22. No methenolone or characteristic major metabolite was detected in samples from subjects who ate meat from the orally dosed chickens. However, 50% of the samples collected 24 h after consumption of the intramuscularly dosed chickens were confirmed positive. Hence, eating meat containing small amounts of injected hormone may constitute a serious liability to the athlete.
EDTA-plasma vs serum differences in cholesterol, high-density-lipoprotein cholesterol, and triglyceride as measured by several methods
Authors: Beheshti I , Wessels L M , Eckfeldt J H 
Published: January 2020

Abstract
To investigate EDTA-plasma/serum (P/S) differences, we collected paired samples from 25 volunteers and measured total cholesterol (TC), triglyceride (TG) and high-density-lipoprotein cholesterol (HDLC), using the Cobas FARA, Ektachem 700, DuPont Dimension, and Baxter Paramax Analyzers. The mean (SD) P/S ratios for TC, HDLC, and TG concentrations were, respectively: 0.980 (0.0171), 1.063 (0.0704), and 0.961 (0.363) for Paramax; 0.976 (0.0189), 1.034 (0.1091), and 0.950 (0.557) for Dimension; 1.003 (0.0221), 1.059 (0.0304), and 0.988 (0.0179) for Ektachem; and 0.993 (0.0162), 1.063 (0.0830), and 1.013 (0.0410) for Cobas. We conclude that P/S ratios vary by analytical methods, and that HDLC ratios tend to be larger in magnitude and in the opposite direction from TC and TG. Both effects lead to significant biases in computed disease risk.
Insights into the ontogeny and activation of T cells
Authors: Mak T W 
Published: January 2020

Abstract
T lymphocytes recognize antigen peptides and major histocompatibility complex products through their T-cell antigen receptors (TcR), consisting of alpha and beta chains. The interaction between T cells and their target cells or antigen-presenting cells is also assisted by a series of other cell-surface polypeptides, most notably CD4 and CD8, which are selectively expressed on mature helper/inducer and killer/suppressor T cells, respectively. Upon engagement of their ligands, a series of signals is transduced intracytoplasmically via some of these molecules and their associated proteins. Perhaps the most important enzyme in this signal transduction process is the lymphocyte-specific tyrosine kinase lck. Another important component is the cell-surface tyrosine phosphatase CD45. This molecule is alternatively spliced and the different isoforms are expressed on the various hematopoietic and lymphopoietic cells. Signaling through the TcR-CD4 D8-lck-CD45 complex is thought to be insufficient to activate T lymphocytes. A costimulatory signal is believed to be essential, and many investigators have suggested that CD28, a ligand for B7/BB1, is such a signal. Immune responses are also controlled by a number of cytokines and soluble factors. Signaling through the tumor necrosis factor receptor p55 is required for clearance of intracellular pathogens. Transcriptional factors involved in controlling interferon production are also important in T-cell development and immune responses. In an attempt to gain a better understanding of the roles of these molecules in T-lymphocyte functions and ontogeny, we generated a series of mutant mice with disruptions in the genes coding for these molecules. We are analyzing the mutant mice to evaluate the importance of these genes in T-cell development.
The clinical immunology laboratory of the future
Authors: Hamilton R G 
Published: January 2020

Abstract
The clinical immunology laboratory assumes the responsibility of providing a complete array of analytical measurements for the diagnosis and management of patients with dysfunction of the humoral (antibody, complement) and cellular (T/B cells, phagocyte) immune system. To identify trends in the activities of the clinical immunology laboratory of the future, I first define the current status of the clinical/diagnostic immunology laboratory, examining six aspects: scope of work, analyte groups, assay methods, specimen types, instrumentation, and standardization. The scope of the clinical immunology laboratory's testing is expected to expand, with a trend toward consolidation of work into fewer, more well-equipped laboratories. An increase is expected in the total number of analytes examined as well as in the numbers of analyte groups and specificities. Assay methods will continue to improve in analytical and clinical sensitivity and specificity, with an emphasis toward less-complex procedures. The primary specimens evaluated will still be serum, urine, tissue, and cells, with a minor expansion into the use of other, less-accessible human body fluids. Instrumentation will move toward increased automation, with the concurrent development of "universal" automated immunoanalyzers for use in humoral and cellular immunology. Finally, standardization of immunological measurements with calibrated reference proteins and antibodies will promote interlaboratory agreement. I describe the diagnostic allergy laboratory to illustrate the immunology laboratory environment.
Plasma vs whole blood for therapeutic drug monitoring of patients receiving FK 506 for immunosuppression
Authors: Winkler M , Ringe B , Baumann J , Loss M , Wonigeit K , Pichlmayr R 
Published: January 2020

Abstract
By retrospective analysis of 13,000 blood samples obtained from 248 patients receiving FK 506 therapy, we compared the suitability of plasma with that of whole blood as the matrix for therapeutic drug monitoring of FK 506. The plasma concentrations did not correlate with the concentrations in whole blood (r = 0.56). In contrast to plasma samples (analyzed by enzyme immunoassay), FK 506 was detectable in all whole-blood samples (analyzed by enzyme immunoassay/microparticle enzyme immunoassay). The inter- and intraindividual variations of FK 506 measurements were greater in plasma than in whole blood. Moreover, plasma concentrations correlated only poorly with clinical events. There was a tendency to greater plasma concentrations being measured during episodes of toxicity, but no clear difference was evident between stable course and rejection. In whole-blood specimens, a correlation between reduced or increased FK 506 concentrations and rejection or toxicity, respectively, was observed. The discriminatory power of whole-blood values was greater for the differentiation between toxicity and stable course than between rejection and stable course. We therefore recommend whole blood rather than plasma as the matrix for therapeutic monitoring of FK 506 concentrations.
Detection of autoantibodies to amylase by ELISA: comparison of detection of macroamylase and free autoantibody
Authors: Hortin G L , Summerfield A L , Wilhite T R , Smith C H , Branum E L , O'Brien J F , Landt M 
Published: January 2020

Abstract
New ELISAs for detecting macroamylase or free autoantibodies to amylase were tested with 48 samples that had been characterized by gel chromatography and electrophoresis. The macroamylase ELISA, with anti-IgG or anti-IgA for detection, detected macroamylase in 28 of 33 samples known to contain macroamylase (85% sensitivity), whereas the ELISA for free autoantibody to amylase was positive for only 11 samples. Specificities of both ELISAs were 93%. Among 28 true positives detected with the macroamylase ELISA, 22 contained IgA, 3 contained IgG, and 3 contained both immunoglobulins. Detection of IgM added no true positives. ELISA responses (y) were proportional to log [macroamylase concentration by chromatography (x)] from 0 to 1200 U/L: y = 5.15 x + 1.66; r = 0.72; Sy x = 1.65. As new tools for detecting macroenzymes consisting of enzyme-autoantibody complexes, the ELISAs show that some autoantibodies are detected more sensitively as antibody-antigen complexes than as free antibody.
Analysis of fatty acid oxidation intermediates in cultured fibroblasts to detect mitochondrial oxidation disorders
Authors: Pourfarzam M , Schaefer J , Turnbull D M , Bartlett K 
Published: January 2020

Abstract
We describe a method for the diagnosis of mitochondrial fatty acid oxidation disorders that is based on the analysis of acylcarnitine and acyl-coenzyme A (acyl-CoA) esters generated during fatty acid oxidation by permeabilized skin fibroblasts. This method requires only small amounts of cultured fibroblasts with minimal preparation, and no isolation of mitochondrial fractions is necessary. During oxidation of [U-14C]hexadecanoate, normal human fibroblasts from patients with fatty acid oxidation defects show a completely different pattern of intermediates, and in each case the observed profile reflects the site of the defect. The diagnosis and likely site of a mitochondrial fatty acid oxidation defect can be made readily from two 80-cm2 culture flasks of fibroblasts with this technique.
Establishment of creatinine clearance reference values for older women
Authors: Sokoll L J , Russell R M , Sadowski J A , Morrow F D 
Published: January 2020

Abstract
Age-adjusted reference ranges for creatinine clearance were determined in 279 women, ages 40-95 years, who were housed in a metabolic research unit and consumed a meat-free diet. Creatinine clearance, but not serum creatinine, declined with age by 0.63 mL/min per 1.73 m2 per year. Serum and urine creatinine concentrations, used to calculate clearances, were analyzed by a kinetic Jaffé procedure. In a subset of 100 subjects, fasting serum creatinine values averaged 8.3 +/- 5.2 (SD) mumol/L higher when measured by the kinetic Jaffé procedure than by an enzymatic method (creatinine PAP). The Cockcroft-Gault formula for estimating creatinine clearance from serum creatinine in women was validated, and the modification factor for the male equation was determined to be 0.84 (95% confidence interval 0.83-0.86) confirming the suggested 15% correction. A prediction formula derived from this population was similar in accuracy to the Cockcroft-Gault formula.
Urea and lactate determined in 1-microL whole-blood samples with a miniaturized thermal biosensor
Authors: Xie B , Harborn U , Mecklenburg M , Danielsson B 
Published: January 2020

Abstract
A miniaturized flow-injected thermal biosensor was developed for the determination of urea and L-lactate in undiluted blood in 1-microL samples. The sensor employed a small enzyme column constructed of stainless steel tubing and microbead thermistors. Urease and lactate oxidase/catalase were separately immobilized onto controlled-pore glass beads, which, in turn, were charged into the enzyme column. With a flow rate of 70 microL/min, linear analytical ranges from 0.2 to at least 50 mmol/L and 0.2 to 14 mmol/L were obtained for urea and lactate, respectively. The relative standard deviations (CVs) for measurements of analyte in buffer were 0.91% for urea and 1.84% for lactate. For urea in whole blood, the CV for 50 determinations was 4.1%. Contrived samples containing various concentrations of urea and L-lactate in whole blood were determined with this sensor and with a spectrophotometric method. Comparisons of the results gave correlation coefficients of 0.989 and 0.984 for 30 blood urea and 30 blood lactate assays in concentrations ranging from 4 to 20.9 mmol/L and from 1.7 to 12.7 mmol/L, respectively.
Hirsutism and acne in women: coordinated radioimmunoassays for eight relevant plasma steroids
Authors: Fiet J , Gosling J P , Soliman H , Galons H , Boudou P , Aubin P , Belanger A , Villette J M , Julien R , Brérault J L 
Published: January 2020

Abstract
We developed and validated a coordinated set of RIAs for the following eight steroids in single small aliquots (&lt; or = 1 mL) of plasma: androstenedione, dehydroepiandrosterone, 11-deoxycortisol, 21-deoxycortisol (21-DF), 11 beta-hydroxyandrostenedione, 17 alpha-hydroxypregnenolone (17-Hpreg), 17 alpha-hydroxyprogesterone, and testosterone. Samples were extracted and then chromatographed on celite microcolumns. Radioiodinated tracers were used for two of the assays (17-Hpreg and 21-DF). Tritiated tracers and scintillation proximity assay counting were used to give separation-free procedures for the other six assays, which considerably improved their practicability and reproducibility. The basal and postadrenocorticotropic hormone plasma values for these steroids in normal women sampled in the follicular phase are presented. Finally, the measurement of the eight steroids as a diagnostic method is evaluated with reference to data from 203 patients with hirsutism and (or) acne.
Electrophoretic fractionation of 5'-nucleotidase
Authors: Panteghini M 
Published: January 2020

Abstract
Human isonucleotidases were separated by electrophoresis on a cellulose acetate membrane. Three 5'-nucleotidase forms, NTP1, NTP2, and NTP3, were resolved with this method and quantified by densitometry. The procedure was not only simple and rapid but also sufficiently precise (between-run CV &lt; 20%) and sensitive (detected nucleotidase fractions of &gt; 0.5 U/L). The effects of various treatments (heat, neuraminidase, glycosidases, proteases, lectins, and detergents) on the electrophoretic pattern of 5'-nucleotidase were studied. NTP1 (mean 12% of total 5'-nucleotidase, SD 5%), NTP2 (mean 30%, SD 8%), and NTP3 (mean 58%, SD 8%) were found in all normal persons studied. The increase in total 5'-nucleotidase in patients with hepatobiliary disease was mainly due to the NTP1 isoform.
Combined polymerase chain reaction-hybridization microplate assay used to detect bovine leukemia virus and Salmonella
Authors: Rasmussen S R , Rasmussen H B , Larsen M R , Hoff-Jørgensen R , Cano R J 
Published: January 2020

Abstract
Here we describe the use of an assay that integrates the polymerase chain reaction (PCR) with hybridization of the amplified product for detection in the same microwell. Traditional PCR requires transportation of the amplified product to another system for characterization of samples. Transportation means time-consuming manipulation and risk of contaminating the laboratory with amplified product. Integration of amplification and specific product detection greatly reduces sample manipulations and the risk of contamination. We used the assay for detection of bovine leukemia virus and Salmonella. The results were identical with those produced by two traditional PCR methods. This assay could easily be adapted for other organisms, simply by using other primers and probes.
Effects of specimen turbidity and glycerol concentration on nine enzymatic methods for triglyceride determination
Authors: Sampson M , Ruddel M , Elin R J 
Published: January 2020

Abstract
We compared the effects of specimen turbidity and glycerol concentration on nine enzymatic methods for triglyceride measurement. We assayed 51 specimens with triglyceride concentrations of 0.85-8.21 mmol/L (75-727 mg/dL) and turbidity at 420 nm equivalent to &gt; or = 0.1 mmol/L (8.8 mg/dL) triglyceride (measured as part of our comparison method). The data were analyzed by multiple regression, which gave coefficients for the effects of glycerol concentration and the change in turbidity during the reaction. The effects of specimen turbidity and glycerol concentration were method-dependent and ranged from 6.20% to -15.67% of the measured result. The magnitude of the turbidity effect (in assays with a significant turbidity interference) was similar to that for glycerol (in assays with a significant glycerol interference). A triglyceride assay with a bichromatic measurement was less subject to interference from turbidity.
Neuropeptides and anxiety: focus on cholecystokinin
Authors: Lydiard R B 
Published: January 2020

Abstract
Cholecystokinin (CCK), a gastrin-like neuropeptide, exists in the central nervous system in several forms. The octapeptide (CCK-8) occurs in predominantly sulfated form (CCK-8S), and the tetrapeptide (CCK-4) occurs in smaller but significant quantities. This review highlights recent developments in preclinical and clinical research into the potential role for CCK in mediating anxiety states. Relevant animal and human studies of administration of CCK agonists are discussed, as well as recent data regarding the concentration of CCK-8S in cerebrospinal fluid from patients with panic disorder, bulimia nervosa, and obsessive compulsive disorder. Finally, the development of agents that specifically antagonize CCK receptors will be described, as will potential therapeutic uses for these new compounds.
Selected strategies for improving sensitivity and reliability of immunoassays
Authors: Kricka L J 
Published: January 2020

Abstract
Selected recent advances in immunoassay are reviewed. Development has continued on new labels (beta-lactamase, pyrophosphatase, luciferases, photoproteins, pyridopyridazines, europium cryptates, metal carbonyl complexes, porphines, phosphors) and label-detection methods (e.g., chemiluminescence assays, thermometric assays, NADP(+)- and FADP-based coupled assays). Various methods have been explored to increase assay sensitivity, including label amplification via catalyzed reporter deposition (peroxidase label) and immuno-polymerase chain reaction (DNA label). The focus of new immunoassay strategies has been on improved reliability (bispecific antibodies), assay simplification (piezoelectric and surface plasmon resonance immunosensors, phase-modulation fluorescence spectroscopy, polymerized bilayer assemblies), and simultaneous multianalyte testing (e.g., quadruple labeling with lanthanides, one-step test devices for drugs of abuse).