bluuebunny/crossref_metadata_2025_split huggingface dataset:
Urinary Glycosaminoglycan Excretion in Rheumatic Diseases
Authors: Kéry V , Orlovská M , Stancíková M , Risko M , Zlnay D 
Published: January 2020

Abstract
We used Alcian Blue (AB) and dimethylmethylene blue (DMB) methods to measure glycosaminoglycan (GAG) excretion in the first morning urine specimens of patients with osteoarthritis (OA), ankylosing spondylitis (AS), and rheumatoid arthritis (RA) in different stages of disease. By the AB method, urinary GAG excretion in patients with RA was not different from healthy control subjects. However, the DMB method showed significant differences (in milligrams of GAG per gram of creatinine) for OA (median 25.4, range 14.3-44.0, P less than 0.01, n = 23) and RA patients (median 33.0; range 10.0-147.6; P less than 0.001, n = 63) in comparison with unaffected individuals (median 20.2; range 8.9-41.4, n = 38). We noted a significant difference in urinary GAG excretion between RA and OA patients (P less than 0.01) and between RA and AS (P less than 0.01) patients. The DMB method was further investigated by clinical decision analysis. The DMB method is simple and rapid and may be useful in diagnosing RA by distinguishing between RA and OA or AS.
Is Free Thyroxine Accurately Measurable at Room Temperature?
Authors: Ross H A , Benraad T J 
Published: January 2020

Abstract
Two recently developed two-step, or "back-titration" assay kits for free thyroxine (FT4)--one based on a europium-labeled derivative of T4, the other on conventional radiolabeled T4--were compared with both symmetrical dialysis and an indirect FT4 radioimmunoassay. Discrepancies between the two-step and the other two methods were observed, particularly in samples that had very low to zero thyroxine-binding globulin (TBG) content. In those instances the two-step methods gave values almost twice as high as the other methods. This effect could be largely reversed in one of the two-step assays and completely reversed in the other by performing the first incubation step at 37 degrees C rather than at room temperature, as prescribed by the manufacturers. When symmetrical dialysis is performed at both temperatures, FT4 at room temperature is about 40% of the amount determined at 37 degrees C, except in zero-TBG samples, where it averages almost 80% of the value at 37 degrees C. Moreover, we demonstrated that the affinity of TBG for T4 is much more temperature-dependent than the affinity of transthyretin and albumin for T4, so that the net temperature effect on the FT4 in a sample depends on the relative contribution of TBG to total binding. We conclude that performing FT4 assays at room temperature is principally incorrect and leads to falsely increased values when samples with very low TBG concentrations are analyzed.
A Study of Experimental Lancets for Blood Collection to Avoid Bone Infection of Infants
Authors: Meites S , Hamlin C R , Hayes J R 
Published: January 2020

Abstract
We describe a study made at two pediatric centers to test experimental lancets for blood collection by skin puncture of infants' heels or fingers. Our primary goal is to decrease the hazard of osseous injury while collecting adequate blood, by using three lancet widths at a constant length of 1.0 mm. The three widths used were 1.0, 1.25, and 1.5 mm. When success at skin puncture was defined rigidly on the basis of the blood volume obtained, the data show that success was related neither to the lancets' dimensions as tested nor to the age of the child, but rather to the phlebotomist's skill and experience, which improved with time.
The History of Proficiency Testing/Quality Control
Authors: Sunderman F W 
Published: January 2020

Abstract
The history and origins of proficiency testing of clinical laboratories are reviewed. Since the introduction of proficiency testing in the late 1940s, dramatic improvement in laboratory performance has been demonstrated. Nonetheless, the poor performance found two decades earlier was summoned to support the passage of the Clinical Laboratory Improvement Act of 1967 (CLIA '67).
How Good are Clinical Laboratories? An Assessment of Current Performance
Authors: Rej R , Jenny R W 
Published: January 2020

Abstract
The Clinical Laboratory Improvement Act of 1967 and Amendments of 1988 (CLIA '67 and CLIA '88) were enacted to ensure that clinical laboratories within the U.S. provide a quality of service that meets clinical needs for good patient care. Approved proficiency-testing programs are to judge the quality of laboratory testing by promulgated performance criteria. We examine the quality of analytical results reported in 1991 to the New York State Department of Health Proficiency Testing program in light of these criteria and analytical goals, based on medical usefulness. Analytical performance is examined for cholesterol, potassium, sodium, calcium, glucose, aspartate aminotransferase, digoxin, and theophylline. In general, proposed CLIA '88 performance standards are compatible with the current state of practice for the population of laboratories examined. Exceptions appear to be digoxin and sodium (failure rate exceeding average) and most therapeutic substances (low failure rate). Sources of analytical bias relative to an accuracy-based target value must be characterized as method-, laboratory-, or matrix-dependent if regulatory programs are to achieve the objective of improving analytical accuracy across all testing sites.
Proficiency Testing Linked to the National Reference System for the Clinical Laboratory: a Proposal for Achieving Accuracy
Authors: Lasky F D 
Published: January 2020

Abstract
I propose using proficiency testing (PT) to achieve one of the important goals of CLIA: accurate and reliable clinical testing. Routine methods for the clinical laboratory are traceable to Definitive (DM) or Reference Methods (RM) or to Methodological Principles (MP) through a modification of the National Reference System for the Clinical Laboratory. PT is the link used to monitor consistent field performance. Although PT has been effective as a relative measure of laboratory performance, the technical limitations of PT fluids and of routine methods currently in use make it unlikely that PT alone can be used as a reliable measure of laboratory accuracy. Instead, I recommend calibration of routine systems through correlation to DM, RM, or MP with use of patients' specimens. The manufacturer is in the best position to assume this responsibility because of also being responsible for consistent, reliable product. Analysis of different manufactured batches of reagent would be compared with predetermined goals for precision and accuracy, as illustrated with data from product testing of Kodak Ektachem clinical chemistry slides. Adoption of this proposal would give manufacturers of PT materials, manufacturers of analytical systems, PT providers, and government agencies time to understand and resolve sources of error that limit the utility of PT for the job required by law.
Laboratory Monitoring of Androgenic Activity in Benign Prostate Hypertrophy Treated with a 5 Alpha-Reductase Inhibitor
Authors: Matzkin H , Chayen R , Goldfarb H , Gilad S , Braf Z 
Published: January 2020

Abstract
Testosterone and androstenedione are metabolized by 5 alpha- and 5 beta-reductases to androsterone (A) and etiocholanolone (E), respectively. These are excreted in the urine as conjugates, and the A/E ratio in normal men is usually greater than or equal to 1.5 (as opposed to 1 in women) because of the high 5 alpha-reductase activity in the prostate. The A/E ratio can be determined simply by gas chromatography after acid hydrolysis of a urine sample, extraction of steroids, and formation of trimethylsilyl derivatives. A timed collection of urine is unnecessary because the ratio of A/E is used rather than absolute values. In men suffering from benign prostate hypertrophy who are treated with Finasteride (a 5 alpha-reductase inhibitor), the A/E ratio decreases to less than 0.5. The A/E ratio decrease can be detected long before there is clinical improvement.
Detection of Hepatitis B Virus DNA in Serum by a Nonisotopic Hybridization Technique
Authors: Akar A , Bournique B , Scholler R 
Published: January 2020

Abstract
We developed a nonisotopic technique, Hepagene, for measuring hepatitis B virus (HBV) DNA in human serum by using a sulfonated probe that is detected by a sandwich immunoenzymatic reaction. The detection limit, determined by serum dilution tests, was 2.5 ng/L. The precision of the Hepagene test was demonstrated by the accurate reproducibility observed for low (3 ng/L) and medium (38 ng/L) concentrations of HBV DNA assayed in 24 different series. Specificity was established by assaying HBV DNA in sera from 98 patients by the Hepagene technique or by a solution hybridization assay with an 125I-labeled probe. Results by both techniques agreed for 94 sera (96%), with 68 being concordant for HBV DNA negativity and 26 for positivity. HBV DNA titers assayed by both methods also agreed. Hepagene represents the first nonisotopic HBV DNA assay involving a sulfonated probe and with performance characteristics equivalent to those of classical radioactive hybridization techniques.
Colorimetric Determination of Potassium in Plasma and Serum by Reflectance Photometry with a Dry-Chemistry Reagent
Authors: Ng R H , Sparks K M , Statland B E 
Published: January 2020

Abstract
We evaluated a colorimetric assay of potassium in plasma and serum with the Boehringer Mannheim Reflotron reflectance photometric analyzer, which is designed for near-patient testing in hospitals and physicians' offices. This potassium method does not require calibration or instrument maintenance by the operator. Analysis of 30 microL of plasma or serum takes approximately 140 s. Within-day imprecision (CV) was 1.0-1.2%. Total CVs over a 1-month period were 1.0-1.4%. Patients' results from the Reflotron correlated well with those from the IL 643 flame photometer and the Beckman Synchron CX3 ion-selective electrode methods. The accuracy of Reflotron values was also verified with Standard Reference Material 956 from the National Institute of Standards and Technology.
Factors Influencing the Reaction of α1-Fetoprotein with Concanavalin A and Lens Culinaris Agglutinin in Crossed Affinoimmunoelectrophoresis
Authors: Magne D , Seta N , Lebrun D , Durand G , Durand D 
Published: January 2020

Abstract
Concanavalin A (Con A) and lentil lectin (LCA) analysis of alpha-fetoprotein (AFP) glycosylation heterogeneity is used in a variety of clinical situations. We studied the influence of analytical conditions on the separation of AFP glycoforms by using lectin-crossed affinoimmunoelectrophoresis, regardless of the AFP concentration, which can vary over a wide range in biological fluids. We defined the optimal concentration of Con A (2 g/L) and LCA (0.35 g/L) in the first-dimension gel, together with the optimum antigen (AFP)/antibody ratio in the second-dimension gel. The presence of protein in the diluent used for AFP samples was found to change the shape of crossed affinoimmunoelectrophoresis patterns without changing the percentage composition of AFP fractions. The within-run CV was less than 4% for both lectins, and the between-run CV was less than 6.3%. The minimal quantity of AFP that provided a visible pattern with both lectins was 4 ng, corresponding to 50 microL of an 80 micrograms/L AFP sample. These technical conditions allow the cellular origin of AFP to be determined, regardless of the concentration in the sample. Typical AFP lectin patterns of secreting tumors are compared with fetal and cord serum AFP.
A Multicenter Evaluation of Lipid Profiling with a Compact Analyzer (Miles Clinistat)
Authors: Hardy R W , Ng R H , Hill R E , Walker S , Sparks K M , Kent S , Lakes C , Hiar C E , Valdes R , Statland B E 
Published: January 2020

Abstract
We evaluated the Clinistat Analyzer (Miles Inc., Diagnostics Division, Elkhart, IN) for measuring cholesterol, triglycerides, and high-density lipoprotein (HDL) cholesterol at three medical centers. The system, based on multilayer film technology, uses precalibrated, dry film reagent disks. Ten microliters of serum is applied to the dry film reagent disk in the test procedure. For HDL-cholesterol measurement, serum is pretreated by precipitation with phosphotungstic acid and magnesium chloride. Total precision (CVs) of each of the three assays was less than or equal to 5%. The assay ranges were linear and satisfactory for clinical use. Patients' results compared well with established methods. No significant interferences were found with hemolysis, icterus, and lipemia.
Short- and Long-Term Variability of Selected Indices Related to Nutritional Status. II. Vitamins, Lipids, and Protein Indices
Authors: Gallagher S K , Johnson L K , Milne D B 
Published: January 2020

Abstract
Five free-living women (ages 23-38 years) who consumed a self-selected diet and five women (ages 23-44 years) residing in a metabolic unit who were fed constant diet were assessed for variation in vitamin and general chemistry indices. Blood was drawn from these women once a month for five months, once a week for five weeks, and once a day for five days to assess analytical and biological variability of the indices. Analytical variability was determined by concurrently analyzing control samples prepared from plasma and serum pools. All samples were analyzed in duplicate. Of the measured indices, vitamins and lipids seemed to be the most variable. Diet had a significant effect only on ascorbic acid. We were unable to show any seasonal change for these analytes. Estimations of analytical variability, along with estimates of biological variability, and knowledge of dietary practices are essential when interpreting differences in analytes.
Enzyme-Linked Immunosorbent Assay of C-Erbb-2 Oncoprotein in Breast Cancer
Authors: Nugent A , McDermott E , Duffy K , O'Higgins N , Fennelly J J , Duffy M J 
Published: January 2020

Abstract
Amplification or increased expression of the c-erbB-2 gene has previously been reported to be a prognostic marker for breast cancer. Gene amplification is usually measured by Southern blotting, whereas increased protein expression is usually detected by immunocytochemistry. We measured c-erbB-2 protein with an enzyme-linked immunosorbent assay (ELISA). High concentrations of oncoprotein were found in 25 of 161 (16%) primary breast cancers and in 3 of 6 (50%) breast cancer metastases. High concentrations were not found in normal breast tissue or benign breast tumors. In the primary cancers, high concentrations of c-erbB-2 protein were found more frequently (a) in estrogen receptor-negative tumors than in estrogen receptor-positive tumors, (b) in progesterone receptor-negative tumors than in progesterone-positive tumors, and (c) in axillary node-positive cancers than in node-negative cancers. Patients with tumors containing high amounts of the c-erbB-2 protein had a significantly shorter (P less than 0.001) disease-free interval and overall survival rate than did patients with low amounts. We conclude that assay of c-erbB-2 protein by ELISA is simple, rapid, and quantitative and offers important prognostic information in breast cancer.
An In-House Opiate Enzymoimmunoassay Based on the Syva Emit® Principle
Authors: Colbert D L , Gooch J C 
Published: January 2020

Abstract
Many laboratories involved in drug-abuse screening use enzymoimmunoassays such as Syva's EMIT system. Although automation has been extensively used to reduce assay costs, further reductions can be achieved by the development of in-house reagents. We have developed our own reagents for the detection of opiates in urine by using the Syva EMIT principle and adapted it for use on an Eppendorf EPOS analyzer. The immunogen was produced from 3-carboxymethylmorphine, and morphine-3-glucuronide attached to glucose-6-phosphate dehydrogenase was used as the tracer. Excellent agreement with Syva's commercial assays was obtained.
Noninvasive Imaging and Spectroscopy--Broad Applications of Magnetic Resonance
Authors: Hornung P A , Schuff N 
Published: January 2020

Abstract
The present utility of nuclear magnetic resonance (NMR) spectroscopy in chemical analysis and magnetic resonance imaging (MRI) in the clinical environment has made this technology commonplace in the chemical industry, clinical medicine, and academic research. The attributes of nuclear magnetism that make the technique especially powerful in biology are discussed. This paper reviews the uses of NMR and MRI, with an emphasis on spatially resolved applications. These applications include imaging, localized spectroscopy, flow sensing, and diffusion mapping from using magnetic-field gradients. The limits of spatially resolved NMR and imaging will be examined in terms of both scientific principles and engineering practice. Block diagrams of both imaging and spectroscopy apparatus are presented and technical requirements of the critical components are discussed. Developing trends in sensing probes, magnets, and applications are highlighted.
Noninvasive Glucose Monitoring in Diabetic Patients: A Preliminary Evaluation
Authors: Robinson M R , Eaton R P , Haaland D M , Koepp G W , Thomas E V , Stallard B R , Robinson P L 
Published: January 2020

Abstract
Noninvasive monitoring of blood/tissue glucose concentrations has been successfully accomplished in individual diabetic subjects by using near-infrared (NIR) spectroscopy coupled with chemometric methods. Three different spectrometer configurations were tested: a) a Fourier-transform infrared spectrometer with an indium antimonide detector; b) a grating monochromator equipped with a silicon (Si) array detector, without fiber optics; and c) a grating monochromator equipped with an Si detector, with fiber-optic sampling. NIR spectra were obtained from diabetic subjects by transmission through the finger during a meal-tolerance test. The maximum range of observed plasma glucose concentrations obtained from the blood samples was 2.5-27 mmol/L. The NIR spectra were processed by using the chemometric multivariate calibration methods of partial least squares and principal component regression. The best calibration yielded a cross-validated average absolute error in glucose concentration of 1.1 mmol/L. This predictive ability suggests that noninvasive glucose determinations by NIR/chemometrics is a viable analytical method.
Near-Infrared Spectrophotometry: A New Dimension in Clinical Chemistry
Authors: Hall J W , Pollard A 
Published: January 2020

Abstract
The near-infrared (NIR) spectral region (700-2500 nm) is a fertile source of chemical information in the form of overtone and combination bands of the fundamental infrared absorptions and low-energy electronic transitions. This region was initially perceived as being too complex for interpretation and consequently was poorly utilized. Advances in chemometric techniques that can extract massive amounts of chemical information from the highly overlapped, complex spectra have led to extensive use of NIR spectrophotometry (NIRS) in the food, agriculture, pharmaceutical, chemical, and polymer industries. The application of NIRS in clinical laboratory measurements is still in its infancy. NIRS is a simple, quick, nondestructive technique capable of providing clinically relevant analyses of biological samples with precision and accuracy comparable with the method used to derive the NIRS models. Analyses can be performed with little or no sample preparation and no reagents. The success of NIRS in any particular case is determined by the complexity of the sample matrix, relative NIR absorptivities of the constituents, and the wavelengths and regression technique chosen. We describe the general approach to data acquisition, calibration, and analysis, using serum proteins, triglycerides, and glucose as examples.
Simultaneous Patient-Side Measurement of Hemoglobin, Glucose, and Cholesterol in Finger-Stick Blood
Authors: Sterling B , Kiang T , Subramanian K , Saltman M , Smart W , Tsay M , Sugarman J , Patel D , Monger D , Martin D 
Published: January 2020

Abstract
We describe a multianalyte assay system for patient-side use comprising single-use plastic cartridges and a small monitor. Hemoglobin, glucose, and cholesterol can be simultaneously measured in 3 min in an unmeasured volume of blood. The sample is drawn by capillary action into four channels for delivery to assay-specific stacks containing a set of closely apposed layers. The distal layer is a membrane that acts as the optical surface for reflectance optics. For glucose and cholesterol assays, erythrocytes are removed by a fibrous filter layer and oxidase-peroxidase chemical reactions contained in the optical membrane generate a colored product. For hemoglobin measurement, blood is lysed by detergent contained in a porous disk. The amount of color reaching the optical membrane is measured by fiber optics. To ensure fail-safe operation, sensors verify sample sufficiency and degree of hemolysis. The assays perform comparably with laboratory methods.
Simultaneous Detection of Seven Drugs of Abuse by the TriageTM Panel for Drugs of Abuse
Authors: Buechler K F , Moi S , Noar B , McGrath D , Villela J , Clancy M , Shenhav A , Colleymore A , Valkirs G , Lee T 
Published: January 2020

Abstract
This novel, competitive immunoassay simultaneously detects seven drugs of abuse in urine. A urine sample is placed in contact with lyophilized reagents, the reaction mixture is allowed to come to equilibrium (10 min), and then the whole mixture is applied to a solid phase that contains various immobilized antibodies in discrete drug-class-specific zones. After a washing step, the operator visually examines each zone for the presence of a red bar. The method incorporates present threshold concentrations that are independent for each drug. In the absence of drug or in the presence of drug in quantities less than the threshold concentration, no colored bar is visible. Samples containing drug(s) at or above the threshold concentration cause a red bar to appear for the appropriate drug(s). Positive and negative procedural control zones are incorporated into each determination. The performance of the assay methodology matches that of instrumented immunoassay systems.
Automated Total and Neonatal Bilirubin Values in Newborns: Is a Distinction Clinically Relevant?
Authors: Langbaum M E , Farber S J , Rosenthal P 
Published: January 2020

Abstract
Guidelines for managing hyperbilirubinemia in newborns were developed by using diazo methods that measure total and direct-reacting bilirubins and calculate an indirect fraction. The automated Kodak Ektachem system allows for measuring serum bilirubin by either of two dry-slide methods: TBIL, involving a modified diazo method, and NBIL, involving a dual-wavelength colorimetric method that fractionates and directly measures the unconjugated (Bu) and conjugated (Bc) bilirubins (Bu+Bc = neonatal bilirubin). The manufacturer recommends that NBIL be used in newborns less than 15 days old, which is impractical in a large, busy hospital laboratory. We compared NBIL and TBIL in 500 paired serum samples from infants less than 15 days old. We noted a statistically significant difference between TBIL and NBIL values (162.9, SD 70.4, vs 164.6, SD 69.2, mumol/L; P less than 0.0001), which was small and of no clinical significance. We conclude that TBIL values may be used with caution for newborn bilirubin screening. Furthermore, NBIL measurements are an acceptable alternative to diazo measurements for neonatal care, allowing the use of previously developed guidelines with NBIL values.