bluuebunny/crossref_metadata_2025_split huggingface dataset:
A kinetic colorimetric assay of gamma-glutamyltransferase.
Authors: Fossati P , Melzi d'Eril G V , Tarenghi G , Prencipe L , Berti G 
Published: January 2020

Abstract
We have explored a kinetic colorimetric method for measuring gamma-glutamyltransferase (EC 2.3.2.2) activity in serum, using L-gamma-glutamyl-3,5-dibromo-4-hydroxyanilide and glycylglycine as donor and acceptor substrates. The released product, 3,5-dibromo-4-hydroxyaniline, reacts with 2,5-dimethylphenol to produce a blue quinone monoimine in the presence of ascorbate oxidase (EC 1.10.3.3). This dye has peak absorption at 610 nm, whereas the donor substrate shows negligible absorption throughout the visible spectrum. The reaction can be run with all the reagents in a single working solution with serum as starter, or with the substrate solution as starting reagent. The sample/reagent volume ratio is 1:24. Adaptation of the method to several automated instruments gave good precision in all cases. Comparison with a method in which L-gamma-glutamyl-3-carboxy-4-nitroanilide is the donor substrate showed good correlation of results (r greater than or equal to 0.987). The dynamic range of the method exceeds the upper limits of the reference intervals for men (9-33 U/L) and women (8-25 U/L) by at least 18-fold.
Use of a reversed-phase evaporation vesicle formulation for a homogeneous liposome immunoassay.
Authors: Canova-Davis E , Redemann C T , Vollmer Y P , Kung V T 
Published: January 2020

Abstract
Complement-mediated release of enzyme molecules from reversed-phase evaporation vesicles serves as the basis of the sensitive homogeneous immunoassay reported here. We found it necessary to co-entrap the substrate glucose 6-phosphate with the bacterial enzyme glucose-6-phosphate dehydrogenase (EC 1.1.1.49) to protect enzyme activity during liposome preparation. Enzyme can be released specifically from these liposomes by incubation with antibody and complement. the enzyme is not merely available to substrate but is actually physically free of the liposomes. Inhibition of this complement-mediated lysis by theophylline is the basis for the homogeneous liposome immunoassay described. The assay results vary linearly with theophylline concentrations in plasma in the clinically relevant range, and serum components do not interfere. The reagents in the assay kit are stable for at least seven months when stored at 5 degrees C. No nontheophylline compounds reacted significantly with the antiserum used. The assay can be run in a kinetic format, with either ultraviolet or colorimetric detection.
Discriminative ability of tests for free and total thyroid hormones in diagnosing thyroid disease.
Authors: Wilke T J , Eastment H T 
Published: January 2020

Abstract
We assessed the sensitivity, specificity, predictive value of a positive result, and efficiency of tests for total thyroxin, free thyroxin index, free thyroxin, total triiodothyronine, free triiodothyronine index, and free triiodothyronine in serum from 1619 consecutive new patients with suspected thyroid dysfunction. Multivariate discriminant analysis was also used. Free thyroxin index and free thyroxin were clearly the most sensitive indicators of hypothyroidism. In contrast, all of these tests identified hyperthyroidism with similar efficiencies. By stepwise discriminant analysis, the free thyroxin index was the most efficient test for distinguishing between euthyroidism and hyperthyroidism and between euthyroidism and hypothyroidism. The combination of tests for total thyroxin, free thyroxin index, triiodothyronine, and free triiodothyronine was optimal for separating euthyroidism, hyperthyroidism, and hypothyroidism. We conclude that the free thyroxin index, despite the introduction of newer technologies, is still the best thyroid hormone test for screening for thyroid disease.
Fluorescence polarization immunoassay for ethosuximide evaluated and compared with two other immunoassay techniques.
Authors: Stewart C F , Bottorff M B 
Published: January 2020

Abstract
We evaluated a new fluorescence polarization immunoassay (FPIA) for ethosuximide in the Abbott TDx and compared results with those by two other ethosuximide immunoassays, EMIT (Syva Co.) and aca (DuPont). The FPIA assay produced within- and between-day CVs of less than 5% at the low, medium, and high ranges of the standard curve. For the ethosuximide FPIA assay the standard curve was stable during the 47 days of the study. By all three methods, we analyzed 100 serum and plasma samples from patients who were receiving ethosuximide. The coefficient of determination (r2) for TDx versus EMIT was 0.973 (slope, 0.96; intercept, -0.80); for TDx vs aca it was 0.985 (slope, 1.00; intercept, -2.44); both relationships were statistically significant (p less than 0.05). Values for patient's specimens were significantly lower by the TDx than by the aca or EMIT methods (p less than 0.05).
Diagnostic quality of laboratory tests as evaluated by graphic comparison of "first test" data, with Reye's syndrome "workup" assays as a model.
Authors: Meites S , Bubis S 
Published: January 2020

Abstract
In the absence of predictive values for quantitative tests ordered in particular diseases, we approximated the comparative diagnostic merit of such tests by graphically reviewing hospital experience with those diseases. As a model, we examined the usefulness of the five chemical tests most commonly ordered on admission as part of the "Reye's workup": aspartate and alanine aminotransferases, NH3, prothrombin time, and glucose. We expressed the data as multiples of the upper reference limit (URL) for each of these liver-function tests, setting the URL high enough to overcome method- and age-related differences. Graphs of "first test" data from 141 patients show the great sensitivity of the two aminotransferase assays for Reye's syndrome: only 2% of the results fall below their URL, whereas about 32% of NH3 determinations and 27% of prothrombin times fall below their URL. Thus measuring the aminotransferases apparently is at least 10 times more useful than the other three analytes as "first tests." Current record keeping does not provide a ready means for assessing the specificity of these tests to determine the number of false positives, but does provide useful data for assessing sensitivity and false negatives.
Plasma apolipoproteins in Tangier disease, as studied with two-dimensional electrophoresis.
Authors: Visvikis S , Dumon M F , Steinmetz J , Manabe T , Galteau M M , Clerc M , Siest G 
Published: January 2020

Abstract
Tangier disease is characterized by a deficiency of high-density lipoproteins and of their major protein constituent, apolipoprotein (apo) A-I. We used high-resolution two-dimensional electrophoresis to examine the principal plasma apolipoproteins (A-I, A-II, A-IV, E, C-II, and C-III) of three persons with Tangier disease, one homozygous patient and his two heterozygous children, comparing the patterns with those for healthy subjects. Characteristic abnormalities were found in the distribution of the isoproteins of apo A-I, there being a normal concentration of pro apo A-I but dramatically decreased concentrations of the other apo A-I isoproteins. We also found hitherto-undescribed polypeptide abnormalities in apo C-III: sialylated and nonsialylated forms of apo C-III appear as double spots having the same isoelectric points but different molecular masses. No other substantial difference was detected in the polypeptide distribution of the other plasma apolipoproteins.
Interference by platelets in the electrophoretic determination of enolase isoenzymes in plasma.
Authors: Viallard J L , Ven Murthy M R , Borocco S , Dastugue B 
Published: January 2020

Abstract
Serum and plasma gave different electrophoretic patterns when enolase isoenzymes were evaluated by electrophoresis on cellulose acetate. Plasma isoenzyme bands were more intense, and there was an additional one (band P) that was not present in serum. We show that, under the conditions of electrophoresis, some of the residual platelets in the plasma are ruptured, releasing intracellular enolases and consequently leading to intensification of the isoenzyme bands. The band P originated from the remaining unruptured platelets. Thus plasma samples must be platelet-free for determination of enolase isoenzyme to be reliable.
Precipitation of serum proteins by the lectin from wheat-germ.
Authors: Schreiber W E , Whitta L 
Published: January 2020

Abstract
We investigated the composition of the precipitate that forms when wheat-germ lectin derived from Triticum vulgaris is added to serum. A number of serum proteins are precipitated, representing about 2.5% of the total serum protein. This study demonstrates that the interaction of this lectin with the bone isoenzyme of alkaline phosphatase is not specific.
Se, Zn, Mg, Ca, K, cholesterol, and creatine kinase concentrations in men during the 12 days after an acute myocardial infarction.
Authors: Speich M , Chappuis P , Robinet N , Gelot S , Arnaud P , Nguyen V G , Nicolas G , Rousselet F 
Published: January 2020

Abstract
We determined concentrations of selenium, zinc, magnesium, calcium, potassium, total and high-density lipoprotein cholesterol, and total creatine kinase (EC 2.7.3.2) in plasma (P) and (or) erythrocytes (E) of 32 men at the time of hospital admission for acute myocardial infarction and then on subsequent days 2, 3, 6, 10, and 12. During these 12 days, only P-selenium and high-density lipoprotein cholesterol concentrations remained unchanged. For the other variables, individual comparison of means indicated the dates of significant changes in concentration (p less than 0.05).
Quantification of two different types of apolipoprotein A-I containing lipoprotein particles in plasma by enzyme-linked differential-antibody immunosorbent assay.
Authors: Koren E , Puchois P , Alaupovic P , Fesmire J , Kandoussi A , Fruchart J C 
Published: January 2020

Abstract
We describe a method for measuring apolipoprotein A-I (ApoA-I) associated and unassociated with apolipoprotein A-II (ApoA-II) in plasma. To directly determine associated ApoA-I, we coated microtiter plates with antibody to ApoA-II, blocked the nonspecific binding sites, and incubated the plate with plasma, immobilizing the lipoprotein particles containing both ApoA-II and ApoA-I. The unbound constituents of plasma were washed away, peroxidase-labeled antibody to ApoA-I was added, the plate rewashed, peroxidase substrate added, and the resulting color measured. ApoA-I unassociated with ApoA-II was evaluated by subtracting the concentration of associated ApoA-I from the total ApoA-I concentration. The method is specific, rapid, and precise. Within- and between-assay CVs were 5.6 and 9.8%, respectively. Analytical recovery of ApoA-I was 94%. The average normolipidemic concentration of ApoA-I associated with ApoA-II in 50 women was 790 mg/L; in 50 men, it was 788 mg/L. The corresponding values for unassociated ApoA-I were 644, 577 mg/L. Both lipoprotein forms of ApoA-I were detected in all major density classes, but were most abundant in high-density lipoproteins. The technique is applicable to measurement of any two apolipoproteins that occur in both associated and unassociated forms in plasma.
Determination of neopterin in serum and urine.
Authors: Werner E R , Bichler A , Daxenbichler G , Fuchs D , Fuith L C , Hausen A , Hetzel H , Reibnegger G , Wachter H 
Published: January 2020

Abstract
Concentrations of neopterin, a product of activated macrophages, in serum from 662 apparently healthy individuals (ages 1 to 97 years, median 22 years) were measured by radioimmunoassay and the results statistically analyzed. Consistent with prior investigations on the urinary excretion of neopterin, we found no significant sex dependence, but values for subjects younger than 18 or older than 75 years were significantly higher. Renal clearance of neopterin in nine healthy individuals was 218 (SD 44) mL/min, which suggests that the kidneys have an active role in neopterin excretion. Results for neopterin concentrations measured in serum by RIA and "high-performance" liquid chromatography (HPLC) are consistent, but for urinary neopterin the concordance between methods was weak. Therefore, the RIA should be used only for measuring neopterin in serum. In comparison of the clinical utility of serum neopterin and urinary neopterin/creatinine concentrations, in patients with gynecological tumors, the latter values (measured by HPLC) discriminated slightly better between patients with favorable and unfavorable prognoses.
On the albumin-dependence of measurements of free thyroxin. II. Patients with non-thyroidal illness.
Authors: Csako G , Zweig M H , Benson C , Ruddel M 
Published: January 2020

Abstract
We studied the relation between thyroxin-binding proteins and free thyroxin (FT4) measurements by five radioimmunoassays (RIA) and an FT4 index (FT4I) in patients with non-thyroidal illness (NTI). The one-step FT4 RIAs and the FT4I frequently failed to identify the true FT4 status (as determined by equilibrium dialysis) of NTI patients. In these patients, falsely low FT4 results with one-step RIAs and FT4I were associated with decreasing total T3 and T4 concentrations, which, furthermore, paralleled decreasing serum albumin concentrations. All NTI patients with "low T3, low T4 syndrome" had subnormal albumin concentration. The two-step RIAs and equilibrium dialysis showed normal FT4 concentrations in most patients with NTI. However, sera from a subset of NTI patients with "low T3 syndrome" gave above-normal FT4 results with these methods. From their predictably poor performance in the presence of a subnormal albumin concentration, we conclude that the one-step FT4 RIAs and FT4I are inappropriate for testing the thyrometabolic status of NTI patients.
Measurement of corticotropin in unextracted plasma: comparison of a time-resolved immunofluorometric assay and an immunoradiometric assay, with use of the same monoclonal antibodies.
Authors: Dobson S , White A , Hoadley M , Lovgren T , Ratcliffe J 
Published: January 2020

Abstract
We describe a time-resolved immunofluorometric assay (IFMA) for corticotropin in unextracted human plasma, based on the use of two monoclonal antibodies: europium-labeled antibody 1A12 and antibody 2A3 coated onto microtiter wells. We compared the results of this assay with those of an immunoradiometric assay (IRMA) performed with the same antibodies working ranges (CV less than 10%) were 25 to 1000 ng/L and 22 to 1000 ng/L for the IFMA and IRMA, respectively, and both assays had comparable detection limits (IFMA 4.0 +/- 1 ng/L, IRMA 3.5 +/- 0.8 ng/L). Results by both assays for 130 patients' samples containing corticotropin within the range 3-100 ng/L and greater than ng/L correlated well (r = 0.88 and 0.92, respectively), and samples with corticotropin in the range 80-624 ng/L gave results that paralleled those for the standard curve. Corticotropin concentrations in apparently healthy subjects were consistent with those reported previously. The IFMA is a simple, precise, and robust assay that can be completed within one day. Its nonisotopic label is stable for at least 50 weeks.
Properties of alkaline phosphatase isoenzymes in plasma of preterm and term neonates.
Authors: Crofton P M 
Published: January 2020

Abstract
The isoenzymes of alkaline phosphatase (EC 3.1.3.1) in plasma of 37 preterm and 21 term neonates two weeks postpartum have been studied with regard to electrophoretic mobility, sialic acid content, inhibition properties, heat lability, molecular mass, and binding to lectins. Term infants generally had a single form of alkaline phosphatase present in significant amounts, identified by the above criteria as originating in bone. All the preterm neonates had two alkaline phosphatase isoenzymes in plasma, namely, bone- and fetal-type intestinal alkaline phosphatase. Liver-, placental-, and adult-type intestinal alkaline phosphatase were not detected in any of the plasma samples.
Validation and application of a liquid-chromatographic/enzymatic assay for individual bile acids in the serum of rats.
Authors: Thompson M B , Blair P C , Morris R W , Neptun D A , Deyo D F , Popp J A 
Published: January 2020

Abstract
A liquid-chromatographic technique with a post-column enzymatic reaction and fluorescence detection was validated for analysis of individual bile acids in the serum of rats. Extraction recoveries averaged 91.1% (SD 6.9%) for all bile acids. The assay was sensitive (minimum detection of 16.8 pmol per 100-microL injection), linear (r greater than 0.999 for concentrations ranging between 45 and 112,500 pmol per 100-microL injection), and reproducible (mean CVs for three different concentrations of standards and a serum pool ranged from 4.4% to 12.2%). In rats treated for three days with either neomycin, carbon tetrachloride, alpha-naphthylisothiocyanate, or total bile-duct ligation (five animals per group), total concentrations of bile acids were significantly increased (P less than 0.004). Concentrations of 16 of 17 individual bile acids differed significantly between groups (P less than 0.04). Examination of the relative concentrations (percent of total) of individual bile acids by canonical discriminant analysis placed each animal into the appropriate treatment or control group. Use of this technique in toxicological studies can help detect and identify specific types of disruptions in the enterohepatic circulation of bile acids.
Inhibitory effect of disulfiram (Antabuse) on alcohol dehydrogenase activity.
Authors: Carper W R , Dorey R C , Beber J H 
Published: January 2020

Abstract
We investigated the effect of disulfiram (Antabuse) on the activity of alcohol dehydrogenase (EC 1.1.1.1) in vitro. We observed a time-dependent inhibition of this dehydrogenase by disulfiram and diethyldithiocarbamate similar to that obtained for aldehyde dehydrogenase (EC 1.2.1.3). These results suggest a possible explanation for various side effects observed in the clinical use of Antabuse.
Multiple drugs of abuse in urine detected with a single reagent and fluorescence polarization.
Authors: Colbert D L , Childerstone M 
Published: January 2020

Abstract
We describe a simple polarization fluoroimmunoassay for the detection of several commonly abused drugs in urine. The single reagent used, prepared by mixing four different antisera and three fluorescein-labeled derivatives, produces a polarization signal that is the average of the individual signals of the derivatives. One adds urine to the pre-mixed reagent, incubates at room temperature for a few minutes, then measures fluorescence polarization. The presence of any of several abused drugs, at concentrations of 1 mg/L or more, noticeably decreases the average signal. Although other combinations are possible, the present assay detects the presence of a cocaine metabolite, amphetamine, and (or) several barbiturates.
Bence Jones proteinuria in multiple sclerosis.
Authors: Pezzoli A , Pascali E 
Published: January 2020

Abstract
We report our findings of Bence Jones proteins (monoclonal free light chains of immunoglobulins) in concentrated urines of patients with multiple sclerosis, by using agarose electrophoresis and immunofixation. The lack of such findings in urines from healthy subjects and patients with other neurological disorders should stimulate further investigation.
Sensitivity of the direct oxalate oxidase assay of urinary oxalate improved.
Authors: Buttery J E , Pannall P R 
Published: January 2020

Abstract
The direct colorimetric method for urinary oxalate has been modified to improve its sensitivity. Oxalate is precipitated overnight with calcium chloride and ethanol, the precipitate is redissolved, and the oxalate is measured by use of oxalate oxidase (EC 1.2.3.4), methylbenzothiazolinone hydrazone, and dimethylaniline. The color developed is more intense, analytical recovery averages 102%, and the overall imprecision is less than 5%. To assess the accuracy of the method, we used a gas-chromatography comparison method and control sera. Interference from ascorbate is negligible. The modified method retains its simplicity and is less expensive.
Chemiluminescence immunoassay for somatomedin C in serum.
Authors: Tode B , Messeri G , Bassi F , Pazzagli M , Serio M 
Published: January 2020

Abstract
To select the best tracer for use in a competitive immunoassay, we conjugated human somatomedin C (SmC) to various chemiluminescent compounds via two different synthetic pathways. Naphthylhydrazides and arylhydrazides, used as the labels, were incorporated via their imidate or their succinimide esters. Conjugating the carboxy terminal of (amino ethyl)ethyl-isoluminol to SmC via a succinimide linkage supplied the most sensitive detection limit and the most immunoreactive conjugate. We developed an immunoassay based on the use of this conjugate, and evaluated dextran-coated charcoal, second-antibody precipitation, and solid-phase immunoprecipitation for separating bound and free label. This chemiluminescent method has a detection limit of 16 pg per tube, and it is accurate and precise. Correlation studies with a conventional radioimmunoassay (x) for SmC gave the following regression equation: y = 0.66x + 3.76 (r = 0.953, n = 30); the slight discrepancies between the two methods are probably ascribable to the use of different antibodies. We thus propose this chemiluminescence immunoassay as an inexpensive and sensitive alternative to radioimmunoassay for measuring SmC in serum or in extracts of serum.
Specific immunoradiometric assay of insulin-like growth factor I with use of monoclonal antibodies.
Authors: Scott M G , Cuca G C , Petersen J R , Lyle L R , Burleigh B D , Daughaday W H 
Published: January 2020

Abstract
We identified two monoclonal antibodies that bind spatially distinct epitopes on insulin-like growth factor I (IGF-I). Using these two antibodies, we developed a simultaneous, two-site immunoradiometric assay (IRMA) specific for IGF-I. This IRMA has no detectable cross reactivity with insulin, proinsulin, prolactin, or somatotropin, and less than 2% crossreactivity with IGF-II. The assay response varies linearly with IGF-I concentrations of 0-800 micrograms/L in serum; the detection limit is about 10 micrograms/L. A comparison of 26 IGF-I serum values from the IRMA and from a previously reported IGF-I specific RIA gave a correlation coefficient of 0.96 with no substantial bias (slope = 1.10). IGF-I values for serum, as an aid in assessing growth abnormalities, are easily (only three pipetting steps) obtained in less than 4 h.
Radioimmunoassay of tumor necrosis factor in serum.
Authors: Teppo A M , Maury C P 
Published: January 2020

Abstract
We present a double-antibody radioimmunoassay for determination of the concentration of tumor necrosis factor (TNF) in serum. TNF in serum competes with a fixed amount of 125I-labeled TNF for the binding sites of specific rabbit antibodies. The bound TNF is precipitated with Sepharose-bound anti-rabbit IgG, then centrifuged, and the radioactivity of the pellets is counted. The detection limit of the assay is 7 ng/L (B0-3 SD). Bound radioactivity in the range of 10% to 90% of the B0 counts corresponds to TNF concentrations of 26 to 10,000 ng/L. Of 40 sera from healthy subjects, 21 (53%) contained TNF concentrations greater than 7 ng/L (range 8-40 ng/L). Some patients with parasitic or neoplastic disease and patients with septic shock had highly increased TNF values. Three of the 14 sera (21%) from patients with rheumatoid arthritis had TNF concentrations greater than 40 ng/L.