bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interpreting the profile of liver-function tests in pediatric liver transplants.
Authors: Simonsen R , Virji M A 
Published: January 2020

Abstract
Results of traditional laboratory tests of liver function were correlated with the clinical course in 26 pediatric patients after liver transplantation. On the basis of clinical outcome after transplantation, the patients were divided into two groups: (a) uncomplicated course with short hospital stay, and (b) post-transplantation course complicated by multiple clinical problems. The patterns of results for tests reflecting liver function--bilirubin (total and conjugated), aspartate (EC 2.6.1.1) and alanine (EC 2.6.1.2) aminotransferases, and gamma-glutamyltransferase (gamma GT, EC 2.3.2.2)--were consistent with the clinical findings in these patients. Values for alkaline phosphatase (EC 3.1.3.1), however, were only rarely increased, even when there was clinical evidence of biliary obstruction. Not only was serum gamma GT increased in obstructive jaundice, but this sometimes was the only test giving results outside the normal limits. We suggest that the persistent and marked increases of gamma GT observed in half of the patients may have resulted from immune-mediated damage to the transplanted liver.
Kits for enzyme determinations compared: relation between composition and quality.
Authors: Peters F P , Hafkenscheid J C 
Published: January 2020

Abstract
Kits of five different suppliers, composed according to the Dutch recommendations for determination of the enzyme activity of alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase, gamma-glutamyltransferase, alkaline phosphatase, and creatine kinase, were intercompared. Activity concentrations of the enzymes in human sera were measured under defined conditions, evaluated, and related to the actual composition of the kits. Concentrations of all kit components were determined by various analytical techniques. The overall results of the activity measurements and the composition of at least three kits inter-agree well. We found deviations as great as 10% in our analytical evaluation of the kits of the other two suppliers, which can partly be accounted for.
Urinary excretion of acetaminophen and its metabolites as studied by proton NMR spectroscopy.
Authors: Bales J R , Sadler P J , Nicholson J K , Timbrell J A 
Published: January 2020

Abstract
Acetaminophen and its glucuronide, sulfate, N-acetyl-L-cysteinyl, and L-cysteinyl metabolites can be rapidly detected by 1H NMR spectroscopy of intact, untreated human urine. Study of the time course of excretion of these metabolites in five clinically normal men after ingestion of the usual 1-g therapeutic dose of the drug showed that the mean 24-h excretion of the drug and these metabolites as determined by NMR was 77.3% of the dose. Respective relative proportions of the above metabolites were 49.9%, 37.6%, 3.0%, and 9.5% (L-cysteinyl plus free drug). Excretion of some other metabolites in urine, including creatinine, citrate, hippurate, and sarcosine was measured concurrently. Excretion of creatinine and sarcosine was closely correlated.
Improved determination of manganese in hair by use of a mini-autoclave and flameless atomic absorption spectrometry with Zeeman background correction: an evaluation in unexposed subjects.
Authors: Guillard O , Brugier J C , Piriou A , Ménard M , Gombert J , Reiss D 
Published: January 2020

Abstract
Motivated by the relatively wide range of values published hitherto, we offer a new, reliable method for determination of manganese in hair from unexposed human subjects. By using a mini-autoclave, we have developed a method that obviates loss of manganese during digestion and, thanks to use of a Teflon receptacle and rigorous methodology, contamination has been minimized. We used Zeeman flameless atomic absorption spectrometry, with the method of standard additions, for quantification. Within-run CVs for concentrations of Mn of 0.26 and 0.28 microgram/g of dry hair were 3.63 and 3.93%; the day-to-day CV for a Mn concentration of 0.29 microgram/g of dry hair was 5.84%. Mean (+/- SD) analytical recovery of Mn added to samples of hair was 104% (+/- 9.2%). The mean concentration of Mn found in the hair of 15 healthy unexposed subjects was 0.26 (+/- 0.05) microgram/g dry weight. This sensitive, reproducible procedure is suitable for use in analysis for traces of Mn in hair.
A mathematical model of the hemoglobin-oxygen dissociation curve of human blood and of the oxygen partial pressure as a function of temperature.
Authors: Siggaard-Andersen O , Wimberley P D , Göthgen I , Siggaard-Andersen M 
Published: January 2020

Abstract
A mathematical model is described giving the oxygen saturation fraction (s) as a function of the oxygen partial pressure (p): y - y0 = x - x0 + h X tanh [k X (x - x0)], where y = kn[s/(1-s)] and x = ln(p/kPa). The parameters are: y0 = 1.875; x0 = 1.946 + a + b; h = 3.5 + a; k = 0.5343; b = 0.055 X [T/(K - 310.15)]; a = 1.04 X (7.4 - pH) + 0.005 X Cbase/(mmol/L) + 0.07 X [[CDPG/(mmol/L)] - 5], where Cbase is the base excess of the blood and CDPG is the concentration of 2,3-diphosphoglycerate in the erythrocytes. The Hill slope, n = dy/dx, is given by n = 1 + h X k X [1 - tanh2[k X (x - x0)]]. n attains a maximum of 2.87 for x = x0, and n----1 for x----+/- infinity. The model gives a very good fit to the Severinghaus standard oxygen dissociation curve and the parameters may easily be fitted to other oxygen dissociation curves as well. Applications of the model are described including the solution of the inverse function (p as a function of s) by a Newton-Raphson iteration method. The po2-temperature coefficient is given by dlnp/dT = [A X alpha X p + CHb X n X S X (1 - s) X B]/[alpha X p + CHB X n X s X (1 - s)], where A = -dln alpha/dT approximately equal to 0.012 K-1; B = (lnp/T)s = 0.073 K-1 for y = y0; alpha = the solubility coefficient of O2 in blood = 0.0105 mmol X L-1 X kPa-1 at 37 degrees C; CHb = concentration of hemoglobin iron in the blood. Approximate equations currently in use do not take the variations of the po2-temperature coefficient with p50 and CHb into account.
Enzymic fluorometric assay of plasma ammonia with a centrifugal analyzer.
Authors: Rodger M R , Jenkins P 
Published: January 2020

Abstract
This method for rapid plasma ammonia determination, supplied in the form of a commercially available kit, is based on a combination of enzymic reaction and fluorometry. Concentrations up to 350 mumol/L can be measured. The detection limit is 15 mumol/L. Intra-assay coefficients of variation for 30 and 100 mumol/L concentrations were 5.0% and 3.0%, respectively. The corresponding interassay CVs were 8.0% and 3.8%. Assay of 16 samples takes about 15 min. Only 25 microL of sample is required, which makes this assay suitable for pediatric use and small-animal research.
Determination of volatile alcohols and acetone in serum by non-polar capillary gas chromatography after direct sample injection.
Authors: Smith N B 
Published: January 2020

Abstract
In this method for detection and quantification of volatile alcohols by capillary gas chromatography, the serum sample is deproteinized, then directly injected into the gas chromatograph with 1-propanol as the internal standard. The capillary column is a 30-m bonded methylsilicone-coated, fused-silica column. With helium as the carrier gas, the injector inlet is set at a split ratio of 1/30 and the average linear velocity in the column is 25 cm/s. Injector and flame-ionization detector temperatures are 280 degrees C, oven temperature 35 degrees C. Chromatography time is less than 3 min.
Silver-stained phenotyping of alpha 1-antitrypsin in dried blood and serum specimens.
Authors: Massi G , Marano G , Patalano F , Auconi P 
Published: January 2020

Abstract
In this technique for determining the electrophoretic phenotype of alpha 1-antitrypsin in dried blood or serum specimens, the adsorbed material is eluted with a concentrated solution of dithiothreitol, focused on polyacrylamide thin-layer gel, and made visible with silver stain. With this staining technique all normal and pathological alpha 1-antitrypsin phenotypes can be detected. The procedure is relatively simple, inexpensive, and suitable for use in large-scale screening for alpha 1-antitrypsin deficiency in selected populations.
Enzyme immunoassay of free thyroxin in serum.
Authors: Ito M , Miyai K , Doi K , Mizuta H , Amino N 
Published: January 2020

Abstract
We describe a double-antibody enzyme immunoassay for free thyroxin (FT4) in serum with use of beta-D-galactosidase conjugated to thyroxin. The method is uninfluenced by thyroxin-binding globulin or albumin. Values for FT4 so determined correlated well with those determined by radioimmunoassay (r = 0.98) and equilibrium dialysis (r = 0.89). The mean variability (CV) within and between assays was 7.4% and 7.6%, respectively. The measurable range of FT4 in serum was 2.8 to 109 ng/L. The FT4 concentrations in serum as determined by this method were 8.4 to 15.5 ng/L for 26 normal adult subjects; 26 to greater than 109 ng/L for 10 patients with hyperthyroidism; less than 2.8 to 8.0 ng/L for seven patients with hypothyroidism; 7.3 to 15.8 ng/L for eight pregnant women; and 12.2 and 13.5 ng/L for two patients with low concentrations of thyroxin-binding globulin.
Single-reagent polarization fluoroimmunoassay for barbiturates in urine.
Authors: Colbert D L , Smith D S , Landon J , Sidki A M 
Published: January 2020

Abstract
We describe a rapid polarization fluoroimmunoassay for screening for the presence of barbiturates in urine. The single reagent is prepared by pre-mixing antiserum with a fluorescein-labeled barbiturate derivative as tracer. Use of a mixture of two sheep antisera, raised against different barbiturate immunogens, results in an assay with a broad cross-reactivity spectrum for most common barbiturates. One adds urine to the pre-mixed reagent, incubates the solution for a few minutes at room temperature, and measures the fluorescence polarization. The tracer/antiserum reagent is stable for at least six months at 4 degrees C. Results compare favorably with two other commonly used screening techniques for barbiturates, thin-layer chromatography and the EMIT-stTM (Syva) system. Although designed as a qualitative screen, some drugs can be quantified by means of a standard curve of the relevant barbiturate.
Stabilized analysis of antidepressant drugs by solvent-recycled liquid chromatography: procedure and proposed resolution mechanisms for chromatography.
Authors: Lensmeyer G L , Evenson M A 
Published: January 2020

Abstract
In this efficient extraction and isocratic liquid-chromatographic procedure for measuring eight antidepressant drugs in serum (amoxapine, 8-hydroxyamoxapine, doxepin, desmethyldoxepin, imipramine, desipramine, amitriptyline, and nortriptyline), they are extracted from serum as a group by use of disposable solid-phase cyanopropyl columns; the eluate is injected directly onto a Zorbax cyanopropyl analytical column. This sample preparation circumvents potential problems of drug instability associated with the usual evaporating/concentrating techniques. Recycling the acetic acid/acetonitrile/n-butylamine mobile phase not only maintains a stable, cost-effective system, it also prolongs column life. Standard curves for all eight drugs are linear to 1000 micrograms/L; the detection limit is 8-10 micrograms/L. For all drugs and metabolites, within-run CVs were 0.9 to 2.2%, between-run CVs 2.1 to 3.8%. Analytical recovery of the solid-phase extraction step was 85 to 100% (mean = 94.5%) for all analytes. Standards and controls, stored frozen in drug-free serum, are stable for at least six months. We also report a study of separation mechanisms.
Determination of enzyme activity in biological fluids by means of electrochemical oxidation of NADH at a modified glassy carbon electrode.
Authors: Bartalits L , Nagy G , Pungor E 
Published: January 2020

Abstract
This amperometric technique for the determination of enzyme activity is based on detecting a decrease in the concentration of the NADH co-factor of the enzyme reaction. A glassy carbon electrode, modified by adsorption of Mg2+ and NADH, is used to measure the anodic peak current that corresponds to the oxidation of NADH. We found no significant difference between the enzyme activity of lactate dehydrogenase (E.C.1.1.1.27) preparations as measured by the above amperometric technique and by a spectrophotometric method.
Precipitation of apo E-containing lipoproteins by precipitation reagents for apolipoprotein B.
Authors: Gibson J C , Rubinstein A , Brown W V 
Published: January 2020

Abstract
We measured the solubility of apolipoprotein E (apo E) after precipitation, with heparin-Mn2+ or dextran sulfate-Mg2+, of lipoproteins containing apo B. Data from 46 randomly selected subjects suggest that apo E is readily precipitated by dextran sulfate-Mg2+, but that heparin-Mn2+ preferentially precipitates apo E associated with apo B-containing lipoproteins while leaving the apo E-containing fraction of high-density lipoproteins (HDL) in solution. In a more detailed analysis of three subjects, we measured the lipoprotein association of apo E by column chromatography on agarose beads, before and after its precipitation from plasma. This study confirmed the preferential solubility of apo E associated with HDL lipoproteins. Using plasma from two normolipidemic subjects, we maintained the heparin concentration at 1.30 g/L and varied the manganese concentration from 9.2 to 184 mmol/L. A 46 mmol/L concentration best separated apo E-containing HDL from apo B-containing lipoproteins. Thus, at these final concentrations, heparin-Mn2+ appears to precipitate the apo E associated with apo B-containing lipoproteins, leaving soluble most of the apo E associated with lipoproteins of HDL size.
An automated, affinity-column-mediated, enzyme-linked immunometric assay for digoxin on the Du Pont aca discrete clinical analyzer.
Authors: Leflar C C , Freytag J W , Powell L M , Strahan J C , Wadsley J J , Tyler C A , Miller W K 
Published: January 2020

Abstract
We describe an automated assay for digoxin that requires a 200-microL sample of serum. Total analysis time is 18 min. The method is extremely precise, with within-run CVs of 2.6, 1.6, and 4.9%, respectively, at 0.5, 1.5, and 3.5 micrograms of digoxin per liter (n = 20). The lower limit of detection is 0.2 micrograms of digoxin per liter. For patients' samples, the correlation with RIA (x) is excellent (r = 0.95; y = 0.95x - 0.14; standard error = 0.17 micrograms/mL). We saw no interferences in samples having high concentrations of rheumatoid factors, lipid, bilirubin, or hemoglobin. Cross reactivity with digoxin analogs and steroidal compounds is similar to that observed by RIA.
Improved assay for alcohol dehydrogenase activity in serum by centrifugal analysis.
Authors: Kato S , Ishii H , Kano S , Hagihara S , Todoroki T , Nagata S , Takahashi H , Nagasaka M , Sato J , Tsuchiya M 
Published: January 2020

Abstract
We describe an improved method for determination of alcohol dehydrogenase (EC 1.1.1.1) activity in 60 microL of human serum, based on conversion of ethanol to acetaldehyde with simultaneous reduction of NAD+ in glycine NaOH buffer (pH 9.0) at 37 degrees C in a centrifugal analyzer. The final concentration of NAD+ was 10 mmol/L and ethanol was 20 mmol/L. The dilution curve was linear with enzyme activity up to 200 U/L, and results by this method correlated well with those by a manual method (N Engl J Med 279: 241-248, 1968). Within-run precision (CV) was 0.9 to 8.2% over the range of 4.5 to 88.1 U/L, and day-to-day precision was 5.4 to 5.6%. In sera from 198 healthy individuals, mean alcohol dehydrogenase activity was 1.6 (SD 1.2, range 0-5) U/L. To evaluate the clinical utility of determining alcohol dehydrogenase, we measured the activity of alanine aminotransferase and alcohol dehydrogenase in sera from 470 patients with various diseases in our hospital, and found that results for the two enzymes did not correlate well.
Automated kinetic assay for lactate dehydrogenase isoenzyme 1 by centrifugal analysis after alkaline inactivation.
Authors: Eckfeldt J H , Kershaw M J , Lewis L A 
Published: January 2020

Abstract
Lactate dehydrogenase isoenzyme 1 (LD1, EC 1.1.1.27) has been used widely as a marker for myocardial infarction, and many analytical methods for it have been developed, most of which are relatively labor intensive. On the basis of a recent report by Takizawa et al. (Clin Chem 29: 1941-1945, 1983) describing the marked stability of LD1 in buffered alkaline solutions, and with use of a centrifugal analyzer, we have developed a fully automated assay for LD1. Results with this method are precise (between-day SD = 2.1 U/L), vary linearly with LD1 activity to 600 U/L, and correlate well with LD1 as determined by immunological (Roche Isomune-LD) and agarose electrophoretic methods (r = 0.985 and 0.986, respectively). Furthermore, the method is easy and convenient, and should provide a substantial savings in labor and reagent costs to laboratories currently determining LD1 by electrophoretic or immunologic methods.
Effect of protein concentration on the determination of digoxin in serum by fluorescence polarization immunoassay.
Authors: Porter W H , Haver V M , Bush B A 
Published: January 2020

Abstract
Determination of digoxin by fluorescence polarization immunoassay (FPIA) with the Abbott "TDx" is significantly influenced by the concentration of total serum protein. Each 10 g/L increase in serum protein results in an 8% decrease in measured digoxin. Studies with [3H]digoxin confirmed that digoxin binds to the protein pellet during the trichloroacetic acid precipitation step before the immunoassay. Serum protein, or equal concentrations of albumin or gamma-globulin, exert an equivalent effect on the apparent digoxin value. Because the total protein concentration of the assay calibrators is low (50 g/L) compared with its reference interval in serum (60-80 g/L), results by FPIA may be expected to be low by an average of 16% (range, 8-24%). Digoxin results by FPIA will be most nearly accurate when the calibrators include a total protein concentration of about 70 g/L. Patients' specimens with abnormally high or low protein content will give falsely high or low results for digoxin.
Performance of the ASTRA enzyme systems evaluated.
Authors: Janssen J W , Verdegaal M C , Visser R W 
Published: January 2020

Abstract
We evaluated the ASTRA enzyme systems for the kinetic measurement of some commonly measured enzymes. The comparison studies with the SMAC and the LKB 8600 show that results by the ASTRA enzyme systems correlate well with those by our routine methods. Studies with several control sera yielded excellent results for both within-run and between-day variation. The response of the photometer is linear up to 3.0 A. For three enzymes the range of linearity exceeded the limits proposed by the supplier, but for lactate dehydrogenase it did not extend as far as proposed. Reagents are stable for at least one week at 16-24 degrees C.
Nephelometry of acute-phase glycoproteins by binding to concanavalin A.
Authors: Pitkänen E M , Palosuo T , Aho K , Putus-Tikkanen T , von Essen R 
Published: January 2020

Abstract
Nephelometry of serum acute-phase glycoproteins by binding to concanavalin A (con-A) was compared with assays for haptoglobin and alpha 1-acid glycoprotein, and for C-reactive protein. The cutoff points for positive reactions were determined on the basis of results for a random sample (n = 130) from a middle-aged population. The sensitivity of the con-A binding assay compared favorably with that of individual acute-phase glycoproteins in a follow-up cohort of 198 patients with inflammatory joint diseases. Unlike the case in many individual acute-phase glycoprotein assays, the distribution of con-A binding values in healthy subjects is remarkably symmetrical, allowing an easy distinction between abnormal and normal values.
Interference of endogenous lactoperoxidase antibodies in a solid-phase immunosorbent radioassay for antibodies to protein hormones.
Authors: Ericsson U B , Larsson I 
Published: January 2020

Abstract
Interference of endogenous antibodies to lactoperoxidase (EC 1.11.1.7) has been demonstrated in a solid-phase immunosorbent radioassay for the detection of antibodies to protein hormones. On enzymic iodination with lactoperoxidase, a little of the 125I is incorporated in the enzyme itself by self-iodination. Because the 125I-labeled lactoperoxidase was not removed from the tracer by chromatography on Sephadex G-50, G-100, and G-200 columns, endogenous antibodies to the enzyme, which were present in 25 of 28 sera from apparently healthy individuals, were detected in conjunction with the measurement of antibodies to growth hormone (somatotropin), prolactin, and thyroglobulin, thus causing false-positive results. Contaminating radioactive lactoperoxidase can be removed by adsorption chromatography on cellulose or by liquid chromatography, and can be avoided by performing the iodination with immobilized lactoperoxidase or with Chloramine-T.
Standardized automated assay for functional alpha 1-antitrypsin.
Authors: Mullins R E , Miller R L , Hunter R L , Bennett B 
Published: January 2020

Abstract
We describe an enzymic assay for the functional activity of alpha 1-antitrypsin, in which tosyl-Gly-Pro-Lys-p-nitroanilide acetate (Chromozym PL) is the trypsin substrate. For the indicating reaction, the concentration of substrate is about double the Km of its reaction with trypsin. This assay is an improvement over reactions involving N-alpha-benzoyl-DL-arginine p-nitroanilide as substrate, the solubility of which in water is less than the Km of its reaction with trypsin. The assay is standardized in terms of active sites of trypsin inhibited per liter of serum, with p-nitrophenyl-p'-guanidinobenzoate as the active site titrant. The results agreed well with those by an immunonephelometric assay for alpha 1-antitrypsin (r = 0.953). The within-run and run-to-run precision was approximately 3%. The results of the assay varied linearly with alpha 1-antitrypsin concentration from 0 to 60 mumol/L of serum. The minimum sample size was 50 microL, and analysis of 24 samples took less than 20 min.
Abbott radiative energy attenuation method for quantifying ethanol evaluated and compared with gas-liquid chromatography and the Du Pont aca.
Authors: Cary P L , Whitter P D , Johnson C A 
Published: January 2020

Abstract
Quantification of ethanol by a radiative energy attenuation (REA) technique was evaluated and compared with results by gas-liquid chromatography (GLC) and by the Du Pont aca. Within-assay CVs were less than 5.5%. Between-assay CVs ranged from 1.9% to 6.0% for serum and blood controls at concentrations of 0.5, 1.0, and 2.5 g/L. We observed no cross reactivity with methanol, isopropanol, or acetone, and analytical recovery of ethanol from serum averaged 101%. For the three-method comparison we performed parallel determinations of 156 blood, 92 serum, and 54 urine samples containing a wide range of ethanol concentrations. Linear regression analysis of the REA results vs those of GLC or aca yielded the following: for serum, REA = 1.03 GLC -0.03 (r = 0.998), REA = 1.13 aca -0.04 (r = 0.999); for blood, REA = 0.97 GLC + 0.05 (r = 0.994), REA = 0.99 aca + 0.06 (r = 0.996); and for urine, REA = 1.01 GLC -0.03 (r = 0.998). We also discuss the clinical and forensic use of the REA method for ethanol.