bluuebunny/crossref_metadata_2025_split huggingface dataset:
Recombinant creatine kinase proteins and proposed standards for creatine kinase isoenzyme and subform assays
Authors: Friedman D L , Kesterson R , Puleo P , Wu A H , Perryman M B 
Published: January 2020

Abstract
We developed standards for creatine kinase (CK; EC 2.7.3.2) assays by expressing human CK cDNAs in COS cells. Cells were transiently transfected with full-length cDNAs for CK subunits M and B, individually and in combination; and subsequently, high concentrations of CK activity were present in the cell lysate (1.2 U/mg protein). These proteins exhibited the characteristic isoenzyme-specific electrophoretic mobilities for CK MM and BB isoenzymes. We also produced subforms of CK MM and MB, identical to the modified CK variants produced in plasma after muscle or myocardial injury, by mutating the cDNA for the CK M subunit to delete the carboxy-terminal lysine residue. When this construct was cotransfected with the normal cDNAs for CK M and B, five electrophoretically distinct CK isoenzymes were detected by nondenaturing electrophoresis: MM3, MM2, MM1, MB2, and MB1. These proteins retained 100% of their activity after storage of the cell lysates -20 or 4 degrees C for 3 months.
Adsorption losses from urine-based cannabinoid calibrators during routine use
Authors: Blanc J A , Manneh V A , Ernst R , Berger D E , de Keczer S A , Chase C , Centofanti J M , DeLizza A J 
Published: January 2020

Abstract
The major metabolite of cannabis found in urine, 11-nor-delta 9-tetrahydrocannabinol-9-carboxylic acid (delta 9-THC), is the compound most often used to calibrate cannabinoid immunoassays. The hydrophobic delta 9-THC molecule is known to adsorb to solid surfaces. This loss of analyte from calibrator solutions can lead to inaccuracy in the analytical system. Because the calibrators remain stable when not used, analyte loss is most probably caused by handling techniques. In an effort to develop an effective means of overcoming adsorption losses, we quantified cannabinoid loss from calibrators during the testing process. In studying handling of these solutions, we found noticeable, significant losses attributable to both the kind of pipette used for transfer and the contact surface-to-volume ratio of calibrator solution in the analyzer cup. Losses were quantified by immunoassay and by radioactive tracer. We suggest handling techniques that can minimize adsorption of delta 9-THC to surfaces. Using the appropriate pipette and maintaining a minimum surface-to-volume ratio in the analyzer cup effectively reduces analyte loss.
Influence of hemoglobin variants and derivatives on glycohemoglobin determinations, as investigated by 102 laboratories using 16 methods
Authors: Weykamp C W , Penders T J , Muskiet F A , van der Slik W 
Published: January 2020

Abstract
Influences of hemoglobin (Hb) variants (HbSS, HbCC, beta-thalassemia, HbAE, HbAS, HbAC, hereditary persistent HbF) and Hb derivatives (carbamylated- and acetylated-Hbs, Schiff base, and those formed in stored blood) on results of glyco-Hb assays by 102 laboratories using 16 different methods were investigated. Affinity chromatography shows deviating results only with homozygous Hb S and C. Correct interpretation of results from patients with decreased erythrocyte half-lives requires previous knowledge on this condition. Measurements of HbA1c by HPLC and electrophoresis are obviously unsuitable for homozygous hemoglobinopathies; for heterozygous hemoglobinopathies and Hb synthesis variants, HbA1c should be expressed as percentage of HbA0 + HbA1c; abnormal Hbs are usually recognized; both carbamylated- and acetylated-Hbs interfere and Schiff base must be eliminated. Except for stored blood, all Hb variants and derivatives gave erroneous results with disposable ion-exchange columns. Dako's immunoassay is not affected by Hb derivatives; glycated Hb variants are not recognized as glyco-Hb and percentages are consequently too low. Glyco-Hb by the immunoassay of Bayer (performed by one laboratory) is not affected by Hb variants and derivatives.
A 10-year analysis of "revenues," costs, staffing, and workload in an academic medical center clinical chemistry laboratory
Authors: Benge H , Csako G , Parl F F 
Published: January 2020

Abstract
From 1980 to 1990 we found progressive increases in workload (number of billable tests; 12.1% per year), staffing [number of full-time equivalents (FTEs); 5.6% per year], "revenues" (gross billings; 25.8% per year), and direct cost (12.9% per year) in the clinical chemistry laboratory of a large tertiary-care university medical center. The increase in direct cost was mainly attributable to an increase in salary cost (23.7% per year), whereas the impact of increasing "consumable" cost was relatively small (5.3% per year). In fact, after adjustment for inflation, the consumable cost was virtually unchanged or decreased during the 10-year study period. Initially, consumables represented about 60% of the direct cost, and the remaining 40% was for salaries. After 1982/83, however, the relative contribution of consumables and salaries to direct cost gradually reversed. Because the workload grew at a higher rate than staffing, the workload per FTE increased from 1980 to 1990. This was paralleled by gradual increases in both "revenue" per FTE and salary per FTE in actual dollars, but by lesser increases to no increases in inflation-corrected dollars. After adjusting for inflation with different indices, the direct cost per test, the consumable cost per test, and the salary cost per test either remained unchanged or decreased in the 1980s. The findings are discussed in the context of technical advancements in laboratory testing, nationwide shortages of medical technologists, and implementation of prospective fixed-fee reimbursement practices during the study period.
Pharmacokinetics of ethanol in saliva: comparison with blood and breath alcohol profiles, subjective feelings of intoxication, and diminished performance
Authors: Jones A W 
Published: January 2020

Abstract
The concentration-time profiles of ethanol were determined for capillary blood, end-expired breath, and saliva after 21 healthy men ingested ethanol at 0.68 g/kg body weight. Near the time of obtaining body fluids, the volunteers estimated their feelings of intoxication, and body sway (with open and closed eyes), hand tremor, positional alcohol nystagmus (PAN), and roving ocular movements (ROM) were quantitatively recorded. The concentration-time profiles of ethanol in blood, breath, and saliva agreed well within individuals but there were large variations between subjects. The mean saliva-ethanol profiles ran slightly above those for blood and breath. Subjective ratings of intoxication and impairment of body function (standing steadiness and hand steadiness) were highest at the time of reaching the peak concentrations of ethanol in body fluids. PAN was evident in most subjects between 60 and 120 min after the start of drinking, whereas ROM appeared mainly during the postabsorptive phase of ethanol kinetics (120-420 min). The blood ethanol concentration thresholds were between 500 and 700 mg/L (50-70 mg/dL) when the diminished performance had recovered to baseline values.
Rapid Zeeman atomic absorption determination of copper in serum and urine
Authors: Wang S T , Demshar H P 
Published: January 2020

Abstract
In this simple, quick procedure for determining copper in human serum and urine, the serum and urine specimens were analyzed directly after dilution with a solution of HNO3 and Triton X-100, 1 mL/L each. We calibrated with aqueous standards for quantitation in Zeeman background atomic absorption spectrometry. By modifying the drying and pyrolysis stages of the graphite furnace atomic absorption spectrometer, we reduced the analytical time to 30 s per determination. The within-run imprecision (CV) is 2.6% and 3.4% and the between-run imprecision is 0.9% and 2.5% for serum and urine copper at concentrations of 30.4 and 2.70 mumol/L, respectively. The accuracy of this fast method was verified by analyzing the National Institute of Standards and Technology Standard Reference Materials SRM 1598 bovine serum and SRM 2670 urine (agreement with certified values within 0.1 mumol/L for serum and within 0.02 mumol/L for urine), by analytical recovery studies (98% recovered in serum, 100% recovered in urine), and by comparison with our normal routine method. We also used the Quebec Interlaboratory Comparison Program to validate the analytical performance. From the precision and accuracy studies, we conclude that this fast-furnace program is a rapid, simple, and reliable method for determining copper in serum and urine.
AccuMeter noninstrumented quantitative assay of high-density lipoprotein in whole blood
Authors: Liu V Y , Lin T Y , Schrier W , Allen M , Singh P 
Published: January 2020

Abstract
A novel noninstrumented technology (ChemTrak AccuMeter) for the quantitative measurement of analytes in biological fluids was reported at the 1990 Oak Ridge Conference (Clin Chem 1990;36:1591-7). This instrument-free technology has been adapted for the quantitative measurement of high-density lipoprotein (HDL). An in situ lipoprotein separation method has been developed and incorporated into the test for HDL determination. The sensitivity of the assay system has been adjusted so that HDL is measured over a clinically significant range of 250 to 1000 mg/L. This compares to a range of 1000 to 4000 mg/L for the total cholesterol in the earlier reported assay. Like the AccuMeter total cholesterol test, the Accumeter HDL test system is self-contained and consolidates blood separation, lipoprotein separation, and specimen measurement into a single step. The test procedure is simple, and the results are accurate.
Ability of two new thyrotropin (TSH) assays to separate hyperthyroid patients from euthyroid patients with low TSH
Authors: Taimela E , Tähtelä R , Koskinen P , Nuutila P , Forsström J , Taimela S , Karonen S L , Välimäki M , Irjala K 
Published: January 2020

Abstract
We evaluated the ability of new thyrotropin (TSH) assays to separate hyperthyroid (n = 50) patients from clinically euthyroid subjects with low TSH values (nodular goiter, n = 20, and nonthyroidal illness, n = 22). Only patients whose serum TSH was &lt; 0.1 mIU/L by immunoradiometric assay were included. We used a new immunofluorometric method based on time-resolved fluorescence (TR-IFMA) and a new immunochemiluminometric assay (ICMA) to measure TSH in serum. Although the differences between the hyperthyroid patients and the euthyroid patients differed from each other by both methods (P = 0.0012 for TR-IFMA and P &lt; 0.0001 for ICMA), there was no cutoff point that could definitely separate the groups. Thus, it is not possible to draw any definite conclusions on whether a patient is hyperthyroid or not, solely on the basis of TSH concentration measured with these new TSH assays.
Specificity of antigen assays of plasminogen activator inhibitor in plasma: Innotest PAI-1 immunoassay evaluated
Authors: Meijer P , Pollet D E , Wauters J , Kluft C 
Published: January 2020

Abstract
We evaluate a new commercial enzyme immunoassay (EIA) of plasminogen activator inhibitor-1 (PAI-1) in plasma, the Innotest PAI-1. Because we wanted to measure PAI-1 in blood samples, we developed a procedure for evaluating the specificity of the assay for different PAI-1 forms in their natural environment. All molecular forms were prepared from a plasma that contained only active PAI-1. The recovery of the different molecular forms of PAI-1, relative to active PAI-1 (100%), was 99% +/- 7% for PAI-1 complexed with recombinant tissue-type plasminogen activator (t-PA), 104% +/- 4% for PAI-1 complexed with melanoma t-PA, 94% +/- 11% for PAI-1 complexed with high-M(r) urokinase, and 113% +/- 3% for latent PAI-1. The parallelism between the calibration curve of the EIA and the serial dilutions of the different PAI-1 forms was considered acceptable for clinical purposes. In selected clinical plasma samples, the PAI-1 values obtained with the Innotest PAI-1 EIA correlated well with those of the TintElize PAI-1 EIA (r = 0.913, n = 106); the observed correlation of the Innotest measurements with PAI activity was r = 0.795 (n = 79). The Innotest PAI-1 antigen assay appears to detect all molecular forms of PAI-1 to a similar degree, and comes close to being the so-called grand total assay for detecting the total molecular concentration of PAI-1 in plasma.
Two-site enzyme immunoassay of CD4 and CD8 molecules on the surface of T lymphocytes from healthy subjects and HIV-1-infected patients
Authors: Carriere D , Fontaine C , Berthier A M , Rouquette A M , Carayon P , Laprode M , Juillard R , Jansen A , Paoli P , Paolucci F 
Published: January 2020

Abstract
A highly sensitive two-site enzyme immunoassay (Capcellia) was developed to determine the concentration of CD4 and CD8 molecules expressed on the surface of human T lymphocytes. This assay, performed in one step (20 min), involves the specific immunocapture of T lymphocytes and reaction of the CD4 or CD8 molecules with an enzyme-labeled monoclonal antibody (mAb). The results were expressed as molar concentrations of the T-cell markers on the basis of results obtained with calibrated CD4 and CD8 standards. The assay was sensitive enough to detect 0.4 pmol/L CD4 or 0.8 pmol/L CD8, which corresponded to approximately 20 x 10(6) CD4+ or CD8+ T cells per liter of blood. Mean concentrations in healthy adults were 17.2 pmol/L for CD4 and 22.1 pmol/L for CD8. The CD4 concentration was &lt; 8 pmol/L in 50% of HIV-1-infected patients and in 95% of AIDS patients. Given the epitopic specificity of the mAb to CD4 we used, these values correspond to the concentration of CD4 molecules free of envelope glycoprotein (gp)120.
Radioimmunoassay of 2-hydroxyestrone in urine
Authors: McGuinness B J , Power M J , Fottrell P F 
Published: January 2020

Abstract
Catechol estrogens such as 2-OH estrone are interesting estrogen metabolites formed in several human tissues and excreted in urine. We developed and thoroughly validated a radioimmunoassay for urinary 2-OH estrone that has several advantages over published RIAs. Because we developed a relatively specific antiserum, we did not include a preliminary chromatographic step to eliminate cross-reacting urinary steroids. We hydrolyzed urinary steroid conjugates with beta-glucuronidase from Helix pomatia because recoveries after acid hydrolysis were only 49.6% compared with 73.8% after enzyme hydrolysis. Published RIAs for urinary 2-OH estrone use acid hydrolysis. Our RIA measured 2-OH estrone independently of the volume of sample, and the detection limit was between 100 and 240 ng/L (10-24 pg per tube). The ED50 was 370 ng/L, and inter- and intraassay CVs for low, medium, and high concentrations were 22.5%, 22.8%, and 19.9%, and 17.4%, 14.3%, and 10.8%, respectively. Median concentrations measured in 14 controls and 33 postmenopausal patients with breast cancer were 0.96 and 1.55 micrograms/g creatinine, respectively, but there was considerable overlap between values from controls and patients.
Four rapid serum-urine combination assays of choriogonadotropin (hCG) compared and assessed for their utility in quantitative determinations of hCG
Authors: Mishalani S H , Seliktar J , Braunstein G D 
Published: January 2020

Abstract
We evaluated the performance of four visually read pregnancy tests (TestPack Plus hCG Combo, ICON II hCG, SureCell hCG-Serum/Urine and PregnaGen 1-Step) designed to detect increased concentrations of choriogonadotropin (hCG) in either serum or urine samples. The biochemical sensitivities and specificity in both serum and urine samples were similar for each kit. All kits correctly identified pregnancy serum samples: The TestPack Plus hCG Combo and SureCell hCG-Serum/Urine were 100% specific; the other two kits exhibited a few false-positive results. For urine samples the ICON II hCG test was 100% sensitive, and the other three were 99.5% sensitive, with false-positive urine results occasionally reported by the PregnaGen 1-Step and ICON II hCG tests. Quantitative hCG concentrations could be estimated in pregnancy serum samples, but not urine samples, through determination of the time elapsed from the sample application or addition of the final reagent to the first appearance of a positive result.
High-performance assays of small molecules: enhanced sensitivity, rapidity, and convenience demonstrated with a noncompetitive immunometric anti-immune complex assay system for digoxin
Authors: Self C H , Dessi J L , Winger L A 
Published: January 2020

Abstract
We report the first clinical application of a noncompetitive immunometric assay system that provides advantages for the rapid and robust assay of small molecules similar to those realized for larger molecules with two-site immunometric assays. This anti-immune complex assay is based on the interaction of a receptor such as a primary antibody with its ligand, such that new binding sites, recognizable by a secondary antibody, are formed. In this report the system is applied to the measurement of digoxin in serum. Utilizing an anti-complex antibody that recognizes a digoxin-bound primary antibody with affinity &gt; 2000-fold over its binding to the primary antibody alone, we show that this anti-complex assay system provides a high-performance assay for serum samples, being conveniently simple (immobilized primary antibody binds digoxin and then labeled secondary antibody so that when excess unbound label is washed away the immunometric readout reflects the digoxin concentration), rapid (incubation time 1-10 min), sensitive (detection limit 30 ng/L), precise (3-4% within-run CV, 1-8% total CV), and free from interference from digoxin-like immunoreactive factors.
Six osteocalcin assays compared
Authors: Díaz Diego E M , Guerrero R , de la Piedra C 
Published: January 2020

Abstract
We evaluated comparatively six commercially available osteocalcin kits: ELSA-OST-NAT IRMA (CIS), ELSA-Osteo IRMA (CIS), Osteocalcin IRMA (Nichols), OSTK-PR RIA (CIS), OSCA Test Osteocalcin RIA (Henning), and Osteocalcin RIA (Nichols). All of them presented acceptable values of variance, sensitivity, and serial dilutions. However, only the ELSA-OST-NAT, ELSA-Osteo, and OSCA Test kits had analytical recoveries near 100% for added purified human osteocalcin; the other assays showed important differences in standardization. After treating samples with antibody against amino acids 43-49 of human osteocalcin, only the ELSA-OST-NAT IRMA detected no residual osteocalcin. Stability of serum values at room temperature and at 4 degrees C is good in the ELSA-Osteo and Osteocalcin IRMAs and in the Henning RIA if serum samples are collected in special tubes available with the kit. Differences in stability and after antibody treatment can be due to the degradation of intact osteocalcin molecules in serum and to osteocalcin fragments detected by assays. Results by different assays were well correlated for samples from controls and postmenopausal osteoporotic women but not for patients with impaired renal function or Paget disease of bone, probably because of osteocalcin fragments accumulated in serum of these patients and differences in specificity of the assays.
Allelic D variants of transferrin in evaluation of alcohol abuse: differential diagnosis by isoelectric focusing-immunoblotting-laser densitometry
Authors: Bean P , Peter J B 
Published: January 2020

Abstract
In the diagnosis of alcohol abuse transferrin (Tf) allelic D variants generate false-positive test results for carbohydrate-deficient transferrin (CDT) as assessed by their electrophoretic migration patterns. The predominant Tf C1 allele encodes a protein for which the most prevalent isoform has a pI of 5.4, i.e., four sialic acids and two bound ion molecules. Carriers of allele D encode Tfs with different amino acid sequences, for which the pI is &gt; 5.7, despite their identical iron and carbohydrate composition. We used isoelectric focusing, immunoblotting, and laser densitometry (IEF-IB-LD) to distinguish Tf D variants from CDT. Alcohol abusers carrying the D chi allele tested CDT+; D chi nondrinkers were CDT-. Although normal controls (&lt; 15 g of alcohol per day for 7-10 consecutive days) carrying variants D1, D2, or D chi exhibited abnormal IEF banding patterns, they did not generate false-positive results for CDT. D3 variants expressed isoforms that migrate at the same pI as CDT bands. Thus, IEF-IB-LD yields a highly resolved banding pattern to distinguish most Tf D variants from CDT.
In vitro analysis of cell-mediated immunity: clinical relevance
Authors: Shearer G M , Clerici M 
Published: January 2020

Abstract
Cellular immunity, a major component of the immune system, contributes to protection against infections and plays a role in the rejection of foreign allografts. T helper cells and the antigen-presenting cells with which they interact provide important functions for cellular immune responses by generating helper signals via soluble molecules known as lymphokines or cytokines. As described here, in vitro analysis of markers of cellular immune function can be used for clinical diagnosis and assessment of therapeutic efficacy and to elucidate the mechanisms of immune dysregulation. Not all helper signals necessarily have the same augmenting effect, because immunoregulatory cytokines that up-regulate the cellular arm of the immune system can conversely down-regulate the humoral arm, and vice versa. The interplay between cross-regulatory cytokines determines which component of the immune system is dominant and can influence the clinical outcome of immunologically controlled diseases. Given the apparent dramatic effects of these cytokines, assays performed in future clinical laboratories should include profiles of immunoregulatory cytokines.
Factors influencing changes in the clinical immunology laboratory
Authors: Nakamura R M , Bylund D J 
Published: January 2020

Abstract
The clinical immunology laboratory is primarily concerned with tests for diagnosing disease and monitoring the therapy and course of diseases mediated by immune mechanisms. In the future, the immunology laboratory will provide test services on a disease-oriented basis and will utilize assays of humoral and cellular immunity, as well as other assays based on molecular techniques. The laboratory scientist will work closely with clinicians and provide interactive consultation. The major factors that will influence future laboratory tests are: (a) governmental regulations, (b) healthcare economics, (c) advances in technology, and (d) advances in development and use of therapeutic agents. Here I discuss the interplay of these factors and their likely effect on the future role of the immunology laboratory.
Verification of reference ranges by using a Monte Carlo sampling technique
Authors: Holmes E W , Kahn S E , Molnar P A , Bermes E W 
Published: January 2020

Abstract
We have investigated the application of Monte Carlo significance tests to the verification of reference ranges in the context of the transfer of an established range from one laboratory to another. Here we present an introduction to the Monte Carlo technique, outline a procedure for performing these tests using a commercially available software program, and demonstrate some of the operating characteristics of the tests when they are used to compare samples of different sizes and variances.