bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rapid, semi-quantitative assay of C-reactive protein evaluated
Authors: Vallance H , Lockitch G 
Published: January 2020

Abstract
We evaluated a new rapid semi-quantitative immunometric assay of C-reactive protein (CRP) as a screening test for sepsis by comparison with an automated nephelometric method. Plasma samples (n = 101) from preterm infants during the first week of life were saved for CRP analyses. We measured CRP by the Nycocard semiquantitative method and compared the results with those obtained with a Behring Nephelometer. A CRP value less than 10 mg/L was considered to be negative for infection. All CRP results read as less than 10 mg/L (negative) by the Nycocard method were also less than 10 mg/L by the comparison method, and all CRP values found to be greater than 20 mg/L (positive) by the Nycocard method were also positive by the comparison method. Results in the 10-20 mg/L range were considered equivocal. We conclude that the Nycocard CRP semi-quantitative method is a rapid and useful screening test for sepsis in preterm infants.
Rapid diagnosis of familial defective apolipoprotein B-100 by Amplification Refractory Mutation System
Authors: Wenham P R , Newton C R , Houlston R S , Price W H 
Published: January 2020

Abstract
We report a method for the diagnosis of familial defective apolipoprotein (apo) B-100, using the Amplification Refractory Mutation System (ARMS) and either whole blood or extracted DNA in the polymerase chain reaction. Normal and mutant alleles are identified by using two allele-specific oligonucleotide primers, each with the same common primer, to amplify a 187-bp fragment of the apo B-100 gene. Fragment amplification occurs only when the allele-specific primer matches the nucleotide sequence of the template DNA. The amplification product is detected by agarose gel electrophoresis, followed by staining with ethidium bromide. The technique is simple, reliable, and robust. It avoids the use of radiation or hybridization with allele-specific oligonucleotide probes, and is well suited for use in the routine clinical chemistry department.
Chemiluminescence immunoassay of aldosterone in serum
Authors: Stabler T V , Siegel A L 
Published: January 2020

Abstract
A chemiluminescence immunoassay (CLI) for the direct measurement of aldosterone in serum was developed with aminobutylethyl isoluminol (ABEI) as the label. In this competitive assay the samples are incubated with sample, antibody, aldosterone-carboxymethyl oxime-ABEI, and paramagnetic particles coated with second antibody. After magnetic separation and washing, the samples are incubated with 200 microL of NaOH (2 mol/L) at 60 degrees C for 30 min. In the luminometer the chemiluminescence is produced by the serial injection of 150 microL each of microperoxidase and H2O2 solutions. Comparison of results with an RIA method showed excellent agreement: CLI = 1.001 RIA + 0.020 (r = 0.99, n = 93). The method is simple and avoids the hazards and costs associated with isotopic waste. The label has a shelf life of at least two years.
31P nuclear magnetic resonance and zero-point titration compared for measuring free magnesium concentration in erythrocytes
Authors: Geven W B , Vogels-Mentink G M , Willems J L , v Os C H , Hilbers C W , Joordens J J M , Rijksen G , Monnens L A H 
Published: January 2020

Abstract
Intracellular ionized magnesium concentrations ([Mg2+]i) were measured in erythrocytes by 31P nuclear magnetic resonance (NMR) and zero-point titration in 14 controls and seven patients with renal magnesium loss. The mean intracellular ionized magnesium concentration in controls measured by 31P NMR was 0.20 (SD 0.03) mmol/L cell water, compared with 0.55 (SD 0.12) mmol/L cell water by zero-point titration. Total erythrocyte magnesium content measured with the lysate method was 0.63 mmol/L cell water higher than estimated by 31P NMR, probably because not all magnesium complexes are fully visible to the NMR technique. We found a positive correlation between plasma ultrafiltrable magnesium and [Mg2+]i irrespective of the [Mg2+]i assay used. [Mg2+]i measured with 31P NMR correlated modestly but significantly with [Mg2+]i determined by zero-point titration (r = 0.58, P less than 0.02). Washing erythrocytes before the zero-point titration decreased the ATP content and the cell water fraction, which led to overestimation of [Mg2+]i by zero-point titration. Although absolute values for [Mg2+]i differ with the assay used, both methods determined significantly lower values for [Mg2+]i in patients with isolated renal magnesium loss.
Concentrations of high-density lipoprotein subfraction HDL2 and lipoprotein A-I in a random population of healthy subjects
Authors: Roche D , Migueres M L , Lequang N T , Burstein M , Ekindjian O G , Girard-Globa A 
Published: January 2020

Abstract
High-density lipoproteins (HDL) are now currently subdivided according either to density and size—HDL2 and HDL3—or to surface apoprotein composition—lipoprotein A-I (LpA-I) without A-II, and LpA-I:A-II. In samples from blood bank donors (60 women, 47 men), we evaluated HDL subclasses, LpA-I particles, and other classic risk factors for atherosclerosis and compared them with each other. We found a good correlation between HDL2 and LpA-I (r = 0.74, P &lt; 0.001), the correlation being more marked in women (r = 0.74) than in men (r = 0.67). LpA-I was also strongly correlated with total apolipoprotein A-I (apoA-I) (r = 0.61), which suggests that LpA-I represents a significant portion of the variable pool of apoA-I. By contrast, LpA-I:A-II but not LpA-I was correlated with HDL3, confirming the preferential association of LpA-I with HDL2. The difference between the sexes was more marked for HDL2 (+66% in women) than for LpA-I (+25%). We conclude that in normolipemic subjects the size of the HDL2 pool depends on that of LpA-I. Considering the speed and low cost of the assay, determination of HDL2 cholesterol might be a useful tool for assessing cardiovascular risk.
Measurement of Porphobilinogen in Urine by a Simple Resin Method with Use of a Surrogate Standard
Authors: Buttery Joseph E , Stuart Sandra 
Published: January 2020

Abstract
In this method for urinary porphobilinogen (PBG), urine is added to Bio-Rad AG1-X2 (200–400 mesh) acetate resin under alkaline conditions and mixed. After two water washes, the adsorbed PBG is eluted with acid and reacted with Ehrlich's reagent (p-dimethylaminobenzaldehyde). Quantification is by comparison of the color developed with that of a PBG standard similarly treated or of a calibrated methyl red solution. The precision of assay of PBG at 20 and 50 μmol/L is 1.4% and 0.9% within-batch and 4% and 3.9% between-batch, respectively. The analytical recovery is about 90%, a proportion that appears to be inherent in the resin method. The proposed method (y) agreed well with the method of Mauzerall and Granick (x; J Biol Chem 1956;19:435–46), yielding the regression equation y = 0.957x + 2.9 (r = 0.993, n = 26). Good agreement was achieved with results determined from the PBG and the methyl red standards. The proposed method is inexpensive, simple to perform, and suitable for routine and emergency use.
Effect of protein concentration on the formation of glycated albumin and fructosamine
Authors: Lamb E , Mainwaring-Burton R , Dawnay A 
Published: January 2020

Abstract
Considerable debate surrounds the question of whether fructosamine concentration should be corrected for serum protein concentration (see 1 for review). Staley (2) has argued against such correction, given that, theoretically, glucose concentration is the rate-limiting step in the glycation reaction; i.e., available lysine residues willalways be in excess of reactive open-chain (carbonyl) glucose molecules, which are only 0.001% of the total (3). However, because the open-chain and cyclic forms of glucose exist in freely exchangeable equilibrium, we conjectured that, as carbonyl glucoses were removed by glycation, more glucose molecules would rapidly isomerize to the open-chainform to maintain the equilibrium, if so, then protein concentration would also be an important factor in determining the glycation rate.
Simple, Rapid Detection of PCR Heteroduplexes in DNA Mutations and Polymorphisms
Authors: Surh Linda C , Shutler Gary G , Korneluk Robert G 
Published: January 2020

Abstract
Detection of nucleotide differences is fundamental among diverse procedures used to study DNA mutations and polymorphisms, whether for basic molecular research or for diagnosis of genetic disorders. Rapid and efficient analysis without radioactive, chemical, or enzymatic modification is currently possible when polymerase chain reaction (PCR) products are electrophoresed on small polyacrylamide gels (5.0 cm × 4.3 cm × 0.45 mm) and stained with silver. The PhastSystemmTM (Pharmacia LKB Biotechnology, Uppsala, Sweden) was initially developed for protein electrophoresis/isoelectric focusing (1) and involves horizontal electrophoresis with an automated staining unit. We have adapted this system to heteroduplex formation of nucleic acids to detect the most frequent mutation in cystic fibrosis (CF), designated ΔF508 (2). This system offers the advantages and uniformity of semi-automated polyacrylamide electrophoresis in a DNA clinical laboratory and the convenience of precast polyacrylamide gels, rapid electrophoretic times (&lt;30 min), and an automated developing chamber where picogram quantities of DNA can be reproducibly silver-stained. Because pre-packaged agarose buffer strips are used, one need not prepare buffer solutions.
Specific measurement of cyclosporine concentrations in whole blood: radioimmunoassay and fluorescence polarization immunoassay compared
Authors: Fuller Kathleen A , Brown Wayne S , Koenig John W , Eveland Barbara J , Scott Mitchell G 
Published: January 2020

Letters
A 39-year-old woman with a 20-year history of hypothyroidism caused by Hashimoto thyroiditis had been managed adequately with oral thyroxun (T4), 200 mg/day, until a few months before referral, at which time she developed symptoms of hyperthyroidism. Her thyroid hormone proffle at the time of referral is shown in Table 1 (Sample 1). Her normal value for serum thyrotropin (TSH) concentration indicates that she was euthyreid but, because of the high serum triiodothyronune (T3) value, the daily oral doseof T4 was decreased to 100 mg. The serum thyroid tests were repeated four weeks later (Table 1, Sample 2): The decreased T4 and increased TSH show that the patient had become hypothyroid at this dosagé of T4 but the serum T3 concentration was still in the high normal range.
False-Positive Titers of Thyroid Autoantibodies in Patients Undergoing Hemodialysis?
Authors: Lukinac Ljerka , Kusic Zvonko , Kes Petar 
Published: January 2020

Abstract
Concentrations of thyroid-related hormones in serum of patients with chronic renal failure are known to be abnormal (1, 2). In our study on thyroid-function testing of patients undergoing hemodialysis, we determined, in addition to concentrations of free and total triiodothyronine, free and total thyroxin, “reverse” triiodothyronine, and thyroxin-binding globulin, the titers of thyroglobulin and microsomal autoantibodies (TGA and TMA, respectively). The study was provoked by the appearance of an uncommon agglutination pattern in the control wells of some samples from patients with chronic renal failure during the standard procedures of detecting TGA and TMA with hemagglutination methods (Thymune-T and Thymune-M assays from Welcome, London, U.K.). For these samples we were not certain whether positive titers for TGA and (or) TMA represented false-positive or true-positive values. Therefore, we assayed the absorbed serum samples and samples after addition of excess nonspecific immunoglobulin. Furthermore, we wanted to determine the difference in TGA and TMA titers of serum samples before and after hemodialysis.
Interferences with Determination of 17-Hydroxyprogesterone in Amniotic Fluid
Authors: Plavšić V , Rogić D , Dumić M , Ille J , Brkljačić Lj , Latin V 
Published: January 2020

Abstract
Continuing our work on the problems of congenital adrenal hyperplasia (CAH) (1, 2), we have established reference values for 17-hydroxyprogesterone (17-OHP) and androstenedione (Δ4) in amniotic fluid(AF) and done 12 successful prenatal diagnoses in families at risk for CAH (3). 17-OHP was determined in the AFs of 105 women in the second trimester of pregnancy with a kit from Sorin-Biomedica (Saluggia, Italy; tritium-labeled 17-OHP, ether extraction). In another 80 pregnant women, 17-OHP was determined with a new Sorin-Biomedica kit (iodine-labeled 17-OHP, ether extraction); a DPC Coat-A-Count kit (Diagnostic Products Corp., Los Angeles, CA), with and without ether extraction; and a CIS Bio International (Gif-sur-Yvette Cedex, France) coated-tubes kit, with and without ether extraction(Table 1).
Discrepancies between methods for amylase in cases of macroamylasemia
Authors: Cobbaert Christa 
Published: January 2020

Abstract
Macroamylasemia is often accompanied by hyperamylasemia and, because naturally occurring macroamylases (e.g., immunoglobulin-bound macroamylases) are usually indistingmshable from normal P- and S-amylases in conventional quantitative amylase assays, the major clinical importance of macroamylase lies in its potential to create confusion during the investigation of possible pancreatitis.
Storage of Methane Breath-Test Samples in Plastic Syringes
Authors: Khin Myo , Genge James R , Bolin Terry D , Htain Win 
Published: January 2020

Abstract
In using gas-chromatographic measurement of breath methane and investigating its relationship to various carbohydrate malabsorption conditions (1,2), breath samples often have to be stored for considerable lengths of time before analysis. Foil gas envelopes, rubber-stoppered glass tubes (Vacutainer Tubes; Becton Dickinson, Rutherford, NJ 07070), and disposable plastic syringes may all be used. The advisability of using glass tubes has recently been questioned (3), after observation of contamination of sterilized, silicone-coated VacutainerTubes with methane. Plasticsyringes would appear to be the most convenient alternative when storage of large sample volumes is required. Because ofthe increase in breath-methane analysis tests used in population surveys and field studies, we examined the limits of storage of methane samples in plastic, disposable 30-mL syringes.
Analytical goals for determinations of theophylline concentration in serum
Authors: Jenny Richard W 
Published: January 2020

Abstract
Statistical principles for analytical goal-setting were applied to two medical applications of drug-monitoring data: (a) individualizing dosage requirements by reference to a population-based therapeutic range or to a patient-specific decision value determined by Bayesian decision analysis, and (b) prospective dosing by using pharmaco-kinetic principles. For application a, the analytical goal for total allowable analytical error (TE) was defined as the amount of error that does not decrease by more than 5% either the sensitivity (probability) for detecting dosage regimens that may require modification or the specificity for detecting appropriately dosed patients. The limiting factor in achievable sensitivity and specificity was the intra-individual variation of peak steady-state concentration (Css), with the TE determined to be a CV of 4%. For application b, error-propagation rules were applied to a proposed prospective dosing scheme (J Pharmacokinet Biopharm 1978;6:135-51). The TE was determined to depend on the rate of theophylline clearance. For clearance rates less than or equal to 0.6 mL/(kg.min), the TE (CV) must not exceed 3% if the predicted infusion rate is to produce, with 95% confidence, a concentration within the therapeutic range.
Methadone concentrations in plasma and their relationship to drug dosage
Authors: Wolff Kim , Sanderson Marion , Hay Alastalr W , Raistrick Duncan 
Published: January 2020

Abstract
We have developed a sensitive HPLC method for measuring methadone in plasma and have used it to establish that there is a linear relationship between plasma concentration and methadone dose over the range of 3-100 mg of methadone per day in a group of 31 addicts. We found a good correlation between dose and plasma concentration (r = 0.89), with the plasma methadone concentration increasing by 0.263 mg/L for every milligram of methadone consumed per kilogram of body weight. Five patients had unexpected high or low concentrations; this finding is discussed.
Use of a synthetic soluble bilirubin derivative to assess interference in creatinine measurements
Authors: Franzini Carlo , Morelli Anna M , Cattozzo Glanpaolo 
Published: January 2020

Abstract
In assessing interference from bilirubin, the use of a synthetic soluble derivative (ditaurobilirubin, DTB) is recommended as a surrogate for the natural conjugates (Bc). We compared the interference effect of unconjugated bilirubin (Bu), Bc, and DTB, using six mechanized methods for serum creatinine measurement. No significant interference was noted in methods that include removal of proteins or in an enzymatic method involving NADH oxidation. Heavy (negative) interference was observed in an alkaline picrate method, and in direct enzymatic methods based on hydrogen peroxide measurement: interference was always more pronounced in the presence of the two soluble derivatives (Bc and DTB), whose interference was of the same magnitude. These results point out the utility of testing for bilirubin interference by using soluble derivatives, in addition to Bu, and suggest the feasibility of using DTB as a surrogate for Bc for this purpose.
Analysis of apolipoprotein E genotypes by the Amplification Refractory Mutation System
Authors: Wenham PhIlIp R , Newton ClIve R , Price WillIam H 
Published: January 2020

Abstract
The Amplification Refractory Mutation System (ARMS) has been successfully applied to the detection of apolipoprotein (apo) E genotypes in human DNA extracted from peripheral blood. By using four allele-specific oligonucleotide primers and one common primer, one can identify the three common alleles of the apo E genetic polymorphism, epsilon 2, epsilon 3, and epsilon 4. The system amplifies two sequences of the apo E gene, one of 181 bp and the other 319 bp. These sequences are amplified when DNA containing a particular allele is incubated with its allele-specific oligonucleotide primer and a common primer. The method is simple, reliable, and nonisotopic and obviates the need for digestion with restriction endonucleases or for hybridization with allele-specific oligonucleotide probes. Genotyping DNA by this method overcomes the problem of post-translational modification of the apo E phenotype encountered with isoelectric focusing of the mature plasma apo E protein.
Mathematical model for comparing proficiency testing results across analytical methods
Authors: AuBuchon James P 
Published: January 2020

Abstract
Proficiency testing (PT) programs may fail to establish a range of acceptable performance in a challenge when an insufficient number of participants use a particular method. In this study I analyzed a mathematical approach to establish acceptable performance in alanine aminotransferase (ALT; EC 2.6.1.2) PT challenges. This approach was derived from the mathematical model used in establishing a nationwide ALT standardization system for blood-collection facilities in 1988. A ratio of results was derived between each method in the PT program and an arbitrarily chosen "standard" method. The intent of this approach was to transform a target value for a challenge as determined in the "standard" method to units applicable to methods utilized less often. However, the high degree of variability over time in the ratios for some methods precluded general application of this approach. Therefore, although this simple mathematical method was successful in implementing an ALT standardization system across different methods, a derivation of this approach did not afford comparison of results in PT challenges.
Increased thrombomodulin values in plasma of diabetic men with microangiopathy
Authors: Tanaka Aklra , Ishii Hldenmi , Hiraishi Sayurl , Kazama Mutsuyoshi , Maezawa Hldenor 
Published: January 2020

Abstract
To study the significance of plasma thrombomodulin (TM) values in diabetes mellitus, we determined plasma TM in 34 patients with non-insulin-dependent diabetes mellitus (NIDDM) men, mean age 54 (SE 2) years. Plasma TM was determined by an enzyme immunoassay with anti-TM monoclonal antibodies. The plasma TM values were significantly greater in NIDDM patients with nephropathy than in patients without nephropathy (P less than 0.001). Also, a significant positive correlation was noted between the concentration of plasma TM and serum creatinine (r = 0.55, P less than 0.001). The plasma TM values of the patients with retinopathy were significantly greater than the values of those without it (P less than 0.002). Furthermore, we noted a significant positive correlation (r = 0.78, P less than 0.001) between plasma TM and the severity of diabetic retinopathy as graded by Scott's classification. These results suggest a close relationship between TM and diabetic microangiopathy.
Osteocalcin concentrations in plasma prepared with different anticoagulants
Authors: Power Michael J , O'Dwyer Bernadette , Breen Eugene , Fottrell Patrick F 
Published: January 2020

Abstract
We investigated the effects on plasma osteocalcin concentrations of different anticoagulants used to collect the blood samples. Plasma osteocalcin concentrations measured by enzyme immunoassay and radioimmunoassay are influenced by the nature of the anticoagulants used. The most significant difference between concentrations found in plasma and serum was seen with oxalate/fluoride anticoagulant, which reduced osteocalcin concentrations to 37.3% of serum values. This is probably related to increased hemolysis with this anticoagulant compared with osteocalcin concentrations in plasma prepared with other anticoagulants. Samples prepared with sodium citrate (0.105 mol/L) or lithium heparin gave values 92.4% and 83.6% of those obtained with matched serum samples. Osteocalcin concentrations were relatively stable in plasma and serum at -20 degrees C for two freeze/thaw cycles. In blood from 100 patients there was a good correlation between osteocalcin concentrations in serum and plasma (lithium heparin) (r2 = 0.831); the slope and intercept (+/- SE) were 0.924 +/- 0.04 and 4.92 +/- 1.25 micrograms/L, respectively. However, in 10 patients, serum osteocalcin concentrations were two- to threefold higher than those in matched plasma samples.