bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of amniotic fluid alpha-fetoprotein reactivity to Lens culinaris agglutinin and concanavalin A in crossed-affinity immunoelectrophoresis: ancillary tests in the prenatal diagnosis of severe fetal malformations.
Authors: Toftager-Larsen K , Kjaersgaard E , Nørgaard-Pedersen B 
Published: January 2020

Abstract
Crossed-affinity immunoelectrophoresis of alpha-fetoprotein in amniotic fluid from 135 normal and 39 abnormal pregnancies (mainly neural-tube defects) was performed with a lectin, agglutinin from Lens culinaris. Results were compared with findings reported for another lectin, concanavalin A. Three fractions of alpha-fetoprotein were obtained by reaction with Lens culinaris agglutinin. The most weakly reactive fraction correlated strongly with the concanavalin A nonreactive fraction. With both lectins, significantly lower concentrations of these fractions were found in all samples from abnormal pregnancies than in those from normal pregnancies. In eight cases with a fetal abnormality the total alpha-fetoprotein concentrations were below the lower limit for abnormal samples. All eight samples revealed fractions weakly reactive with Lens culinaris agglutinin below the lower 0.1% limit for normal samples; seven of these samples had fractions nonreactive with concanavalin A below this limit. Although a decrease in the two described fractions in normal pregnancies was found with increasing gestational age, we find either method to be valuable as an ancillary test in the prenatal diagnosis of fetal neural-tube defects and other malformations.
Unpredictable error in calculated bicarbonate homeostasis during pediatric intensive care: the delusion of fixed pK'.
Authors: Rosan R C , Enlander D , Ellis J 
Published: January 2020

Abstract
Bicarbonate balance is usually calculated from indirect total CO2 values determined by blood-gas analysis. Total CO2 is computed from the Henderson-Hasselbalch equation, under the assumption that the pK' is constant or at most varies insignificantly. In pediatric patients in intensive care, we have found instances of large errors in this assumption. We join Natelson and Nobel in asserting that total CO2 should be measured. Little reliance should be placed on bicarbonate estimation.
An immunoradiometric assay for erythrocyte complement (C3b) receptor activity applied to a pediatric population with connective tissue disease.
Authors: Buffone G J , Leatherwood C M , Person D A , Brewer E J 
Published: January 2020

Abstract
The number of receptors for complement component C3b per erythrocyte reportedly is decreased in over half of adults with systemic lupus erythematosus. We have devised an immunoradiometric assay for C3b receptor (CR1) on erythrocytes, with which one can assess CR1 saturation due to in vivo binding of immune complexes or activated complement fragments (C3b). Using this assay, we examined binding by CR1 in normal adults and newborns, in lupus and juvenile rheumatoid arthritis patients, and in a population of patients with various general medical problems, including other connective tissue diseases. Binding by CR1 was decreased in eight of 15 SLE patients, four of 25 juvenile rheumatoid arthritis patients, and one of 14 patients with other diseases. We found no significant correlation between CR1 binding and either C1q binding, antinuclear antibody titer, results for complement C3 and C4, or the presence of renal disease. Using this assay, we were also able to show that the observed reduction in CR1 binding was not ascribable to prior saturation of CR1 or to blocking antibody against CR1. The assay is precise and easy enough for routine application.
Comparison of a commercially available assay system with two reference methods for the determination of plasma cholinesterase variants.
Authors: Whittaker M , Britten J J , Dawson P J 
Published: January 2020

Abstract
For assaying plasma cholinesterase (EC 3.1.1.8) activity and phenotyping by means of dibucaine inhibition, we have compared a commercially available kit, in which butyrylthiocholine is used as substrate, with two reference methods, one using benzoylcholine and the other propionylthiocholine. With 50 different samples of three of the most common genetic variants, we could clearly differentiate the variants with benzoylcholine and dibucaine, whereas there was some overlap of the E1uE1u and E1uE1a phenotypes with the other two substrates at 30 degrees C. The phenotypes were better differentiated at 25 degrees C, and in our hands the use of butyrylthiocholine was preferable to propionylthiocholine for phenotyping with dibucaine. The affinity of the usual and atypical homozygotes for fluoride with butyrylthiocholine gave an inverted response to the affinity of these variants for the anion with benzoylcholine. We suggest that this may be explained by the role of the chromogen or its products in the assay procedure with the thiocholine substrate.
Time-resolved fluoroimmunoassay of human pancreatic phospholipase A2.
Authors: Eskola J U , Nevalainen T J , Lövgren T N 
Published: January 2020

Abstract
We describe an immunofluorometric assay for human pancreatic phospholipase A2 based on time-resolved fluorescence. The labeled antibody technique in combination with the time-resolved 1-s fluorometric detection of the europium label, which essentially eliminates all background fluorescence, resulted in a high sensitivity (20 ng/L) and a wide (5000-fold) linear range. Nonspecific binding was minimized by treating the solid-phase antibody with NaSCN before coating, to remove endogenous antigen, and by immunosorbent purification of the antibody before labeling with europium. This is a one-incubation, multi-site, solid-phase assay on polystyrene microtiter strips, even though a polyclonal antibody was used. As measured by this assay, activity of immunoreactive phospholipase A2 was found to be above normal in sera of patients suffering from acute pancreatitis.
Electroimmunoassay of albumin in human serum: accuracy and long-term precision.
Authors: Pascucci M W , Grisley D W , Rand R N 
Published: January 2020

Abstract
An improved procedure for the Laurell "rocket" technique is described. Samples were electrophoresed in an agarose gel containing anti-human albumin. The gel plates were processed, the peaks stained, and peak heights used to calculate albumin concentrations. Factors affecting precision were (a) adequate heating of agarose gel before antibody is added, (b) accurate leveling of the gel surface during plate formation, (c) applied voltage during sample application, and (d) avoidance of the "edge" effect on sample placement in the gel. Multi-plate long-term precision (CV) for the method was 6.2% at a mean albumin concentration of 13 g/L and 3.0% at 37 g/L. Analytical recovery of 8 and 11 g of albumin per liter was 99 to 100%. There was negligible interference from hemoglobin and dextran as well as several common substances that bind to albumin--bilirubin and salicylate. Because of its high accuracy and good long-term precision, the method is a possible candidate reference method for serum albumin.
Direct measurement of testosterone in a pediatric center, with use of a radioimmunoassay kit and unextracted serum.
Authors: Funderburgh L J , Zipf W B , Sotos J F 
Published: January 2020

Abstract
We evaluated a commercial (Radioassay Systems) radioimmunoassay kit for testosterone in which a double-antibody method and an 125I tracer are used. The 50-microL serum sample is assayed directly with no pre-extraction step. The assay system has good sensitivity (0.01 microgram/L), good precision (CV 5.2%), and little cross reactivity between testosterone and other androgens. Results compared well with those by a tritiated radioimmunoassay involving extraction (r = 0.98). Values obtained for 97 children compared well with published pediatric normal values. Evidently, this kit provides a rapid and reliable measurement of testosterone in serum specimens and is acceptable for use with pediatric patients.
24,25-dihydroxyvitamin D3 in serum: sample purification with Sep-Pak C-18 cartridges and liquid chromatography before protein-binding assay.
Authors: Traba M L , Babé M , de la Piedra C , Marín A 
Published: January 2020

Abstract
We describe a precise, specific method for measuring 24,25-dihydroxyvitamin D3 in human serum. A 2-mL serum sample is extracted with acetonitrile and passed through a Sep-Pak C-18 cartridge. The sample is further purified by "high-performance" liquid chromatography under isocratic conditions on a normal-phase column (Radial-Pak silica-gel cartridge), then subjected to a protein-binding assay. The mean concentration of 24,25-dihydroxyvitamin D3 in serum from 22 normal adults (measured during the spring) was 2.9 micrograms/L (SD 1.9, range 6.3-0.42 microgram/L). The intra-assay CV was 7.7%, the interassay CV 11.2%. Purification of the sample with Sep-Pak C-18 and liquid chromatography on normal plus reversed-phase columns leads to a mean value of 3.4 micrograms/L (SD 1.6 micrograms/L, n = 12), not significantly different from results with our method.
Evidence for interference by ascorbate in the measurement of cerebrospinal fluid glucose by a kinetic glucose oxidase/peroxidase procedure.
Authors: Maguire G A , Price C P 
Published: January 2020

Abstract
Glucose in the cerebrospinal fluid (CSF) of neonates, as measured with a kinetic glucose oxidase/peroxidase procedure, was sometimes very low. When these samples were stored at 4 degrees C and subsequently re-analyzed, or if the samples were analyzed at any time after receipt by using a glucose dehydrogenase assay, the values were much higher. We found that the discrepancies in the values were caused by a lag phase in the kinetic method, during which no color developed. Because the lag phase exceeds the time over which the reaction is monitored in the kinetic procedure, this leads to the erroneously low values. The interference could be reproduced experimentally by adding ascorbic acid to CSF or plasma samples, or removed by adding ascorbate oxidase to CSF samples. Plasma glucose, as estimated by the kinetic glucose oxidase method, showed no such interference.
An evaluation of 10 kits for determination of human choriogonadotropin in serum.
Authors: Rasor J L , Farber S , Braunstein G D 
Published: January 2020

Abstract
We compared 10 commercially available radioimmunoassay kits (American Diagnostics, Becton Dickinson, BioGenex, Clinical Assays, Hybritech, Leeco, Mallinckrodt, Microanalytic, Nuclear Medical Systems, and Radioassay Systems) for determination of human choriogonadotropin (hCG), using serum pools, hCG CR119 (NIH), 2nd I.S. (who), and 1st I.R.P. (who). Criteria were ease of performance, total assay time, sensitivity, potency, and parallelism as compared with reference standards and results for 15 serum pools. The Mallinckrodt kit exhibited the best overall performance, with good low-concentration sensitivity, parallelism with two of the three reference preparations, and good clinical correlation as compared with the reference kit from NIH. Because the antibodies used in the kits are occasionally changed by the manufacturers, these results are necessarily valid only for kits that include reagents identical to those in the kits that we tested.
Liquid-chromatographic determination of alpha- and gamma-tocopherols in erythrocytes, with fluorescence detection.
Authors: Lehmann J , Martin H L 
Published: January 2020

Abstract
We have adapted to erythrocytes a method for the determination of alpha- and gamma-tocopherols in plasma and platelets. Erythrocytes (50 microL) were extracted with methanol containing tocol (internal standard) and pyrogallol. Tocopherols were partitioned into chloroform, washed, and injected in methanol onto a reversed-phase (C18) "high-performance" liquid-chromatographic column. The mobile phase was methanol/water (99/1 by vol) at a flow rate of 2 mL/min and detection was with a "high-performance" spectrophotofluorometer. The limit of detection for either tocopherol is 0.10 microgram/mL of packed cells. Analytical recoveries ranged from 93 to 104%. Some values for tocopherols in human erythrocytes are presented.
A unique protein in normal human cerebrospinal fluid.
Authors: Papadopoulos N M , LeWitt P A , Newman R P , Raphaelson M I , Chase T N 
Published: January 2020

Abstract
On analysis of cerebrospinal fluid (CSF) samples from normal volunteer donors by high-resolution zone electrophoresis on agarose gel, an electrophoretically homogeneous protein band consistently appeared in the gamma-globulin region. Application of immunofixation electrophoresis in attempts to identify the band with use of monospecific antibodies against individual human serum proteins and against heavy- and light-chain immunoglobulins as well as polyvalent antisera did not produce a positive immunoprecipitation reaction with the protein band. The serum samples from these subjects did not show similar bands. Therefore, we conclude that this protein band is a normally occurring protein that is unique to CSF.
Monoclonal antibodies to human plasma low-density lipoproteins. II. Evaluation for use in radioimmunoassay for apolipoprotein B in patients with coronary artery disease.
Authors: Patton J G , Badimon J J , Mao S J 
Published: January 2020

Abstract
We describe the importance of the low-density lipoproteins (LDL) used in preparing radioimmunoassay standard curves and the clinical application of monoclonal antibodies to LDL. LDL isolated from five normal men produced five parallel displacement curves with conventional mouse antiserum but there was a significant difference of immunoreactivity among the LDL. None of our four monoclonal antibodies could eliminate the heterogeneous immunoreactivity of different LDL. Thus, the determination of plasma apolipoprotein (apo) B will vary depending on the selection of LDL standards, and the comparison of absolute apo B values between laboratories will be of questionable value unless they use the same LDL standard. Nonetheless, in a radioimmunoassay our monoclonal antibody, LP-22, detected a more significant (p less than 0.0001) increase of plasma apo B in patients with angiographically documented coronary artery disease than did conventional antiserum (p less than 0.001). In addition, the overlap of apo B concentrations for patients with and without disease was less when monoclonal antibody LP-22 was used. We conclude that patients with coronary artery disease have a significant increase in the form of plasma apo B that is specifically recognized by LP-22 monoclonal antibody. Perhaps monoclonal antibodies will be able to sort out the various components of apo B, delineate their possible atherogenic roles, and offer us a predictive value for diagnosing such patients.
Effect of short-term storage conditions on alcohol concentrations in blood from living human subjects.
Authors: Winek C L , Paul L J 
Published: January 2020

Abstract
We examined the effects of time, temperature, and a preservative (sodium fluoride) on ethanol concentrations in stored samples of whole blood from living human subjects. We measured the ethanol in the first, second, seventh, and 14th day of storage, by gas chromatography. Samples were stored at 0-3 degrees C and at 22-29 degrees C, with and without preservative. None of these showed significant gains or losses in concentration. The average differences between ethanol as measured on the day of collection and after storage were all within the range of experimental error of the method (+/- 5%).
Evaluation of a solid-phase enzyme immunoassay for human choriogonadotropin beta subunit.
Authors: Davey D D , Sample M M , Oei T O 
Published: January 2020

Abstract
We evaluated a quantitative solid-phase enzyme immunoassay for human choriogonadotropin beta subunit (beta-HCG) with anti-beta-HCG:horseradish peroxidase conjugate, recently marketed by Abbott Laboratories. We compared results on 56 patients' serum specimens, obtained mostly for followup of neoplastic disease, with those by a competitive radioimmunoassay kit. The correlation was good, the differences being of little clinical significance. Linear regression in the low and intermediate ranges gave a slope of 0.93, a y-intercept of 0.34, and a correlation coefficient of 0.97. Precision studies yielded an interassay CV of 6.4% in the intermediate range and 13% in the low range. Sensitivity was 0.69 int. unit/L. Cross reactivity was 1 to 2% with specimens fortified with lutropin or follitropin. The only substantial problem was with linearity in the upper part of the standard curve, especially in the interval, 100-200 int. units/L. This problem is obviated by adequate sample dilution.
Assay of urinary oxalate: six methodologies compared.
Authors: Zerwekh J E , Drake E , Gregory J , Griffith D , Hofmann A F , Menon M , Pak C Y 
Published: January 2020

Abstract
To assess how well results by different methods for urinary oxalate determinations agree with each other in a clinical setting, we compared six different assays: Hodgkinson and Williams (Clin Chim Acta 36:127-132, 1972), enzymatic, modified Hodgkinson and Williams, gas chromatography, ion chromatography, and "high-pressure" liquid chromatography. For the entire group of samples, the mean value by each method agreed relatively closely, although the enzymatic procedure produced a somewhat higher value. All six methods had large coefficients of variation within (8-58%) and between (15-88%) assays. In addition, analytical recovery by most assays was more than 100% of the added oxalate. Analytical recovery of 10 micrograms of oxalate added per milliliter of urine specimen ranged from 86 to 237%; for 20 micrograms/mL it was 83 to 320%. Thus for the six methods evaluated, no single method appeared to be superior to the others.
Changes in serum iron and leukocyte count associated with open-heart surgery.
Authors: Fitzsimons E J , Ballantyne G H 
Published: January 2020

Abstract
Rapid and pronounced changes in serum iron concentration and leukocyte count in association with open-heart surgery were observed in each of 58 patients. We examined the temporal aspects of these alterations. An initial increase in Fe concentration from a mean of 0.94 mg/L before surgery to 1.20 mg/L was observed within 6 h of the start of surgery. Decreased Fe concentration, a phenomenon previously associated with physiologically stressful events, became apparent 12 h after surgery, by which time the mean Fe concentration had declined to 0.26 mg/L. An increase in the mean leukocyte count, from 7.1 to 15.2 X 1000/mm3 was observed within 6 h of the start of surgery. An increase in ferritin concentration in serum was concurrent with decreased iron concentration.
Spectrophotometry of occult blood in feces.
Authors: Welch C L , Young D S 
Published: January 2020

Abstract
This method for measuring fecal occult blood is based on the heme-catalyzed oxidation of tetramethylbenzidine by H2O2. An aliquot of heated stool homogenate is mixed with acetic acid to chemically separate heme from globin. The heme is extracted into ethyl acetate and reacted with the reagent and H2O2 to produce a green oxidation product. The reaction is followed kinetically for 30 to 60 s at 660 nm. A660 is linearly related to the amount of hemoglobin. The lower limit of detection is 1 to 2 mg of hemoglobin per gram (wet weight) of feces. Within-day precision (CV) of the analysis for hemoglobin added to stool specimens (4 to 30 mg/g) ranged from 2.3 to 7.6%, between-day CV from 2.1 to 8.1%. Analytical recovery of hemoglobin added to fecal specimens (4 to 30 mg/g) ranged from 86.7 to 106.2%. Of the substances known to interfere with conventional dye-oxidation tests for fecal occult blood, only myoglobin and ascorbic acid interfere with hemoglobin quantification by our procedure. The test is fast, inexpensive, and easy to perform, and involves equipment available in hospital laboratories.
Interference with carcinoembryonic antigen radioimmunoassays by glycosaminoglycans, and their removal.
Authors: Wu J T , Mau E , Knight J A 
Published: January 2020

Abstract
Using the reagents from the CEA-Roche kit, we found that solutions containing only glycosaminoglycans (GAG) yielded false concentrations of carcinoembryonic antigen (CEA), and mixtures of CEA and GAG produced falsely high values. On the other hand, solutions of GAG yielded no additional CEA concentration when reagents from the Abbott CEA kit were used; rather, the CEA result was decreased with the Abbott kit for a CEA solution also containing GAG. These effects of GAG were not ascribable to contamination, because neither gel filtration nor ion-exchange column chromatography separated the false Roche CEA content related to GAG from their peaks of uronic acid or from their anticoagulant activity. In addition, an enzyme specific for GAG eliminated these GAG-derived false concentrations. Both the positive and negative effects are correlated with concentrations of GAG. We found that the concentration of GAG could be decreased in a solution containing plasma proteins by either heating (70 degrees C, 15 min) or treating with perchloric acid (0.6 mol/L). The former is superior because essentially all GAG added to a solution containing plasma proteins were removed by heat, whereas as much as 25% to 80% of the GAG still remained after acid treatment. The effect of GAG was also completely eliminated by treating the specimens with chondroitinase ABC lyase (EC 4.2.2.4).
Preliminary isolation of urinary placental estriol before gas or liquid chromatography.
Authors: Andreolini F , Di Corcia A , Laganà A , Samperi R , Raponi G 
Published: January 2020

Abstract
We describe a rapid, simple assay for placental estriol in urine, involving a small sample volume (250 microL) and, correspondingly, a small amount of enzyme reagent. After hydrolysis, estriol is adsorbed from urine onto graphitized carbon black (Carbopack B). After some washing steps, estriol is desorbed with a small volume of a suitable mobile phase. This single-step purification technique is rapid (about 15 min), with minimal sample manipulation. Analytical recoveries for estriol-supplemented urine ranged from 95.9 to 101.0%. Ten replicate analyses of urines containing typical concentrations of estriol gave CVs of 3.3, 2.6, and 2.4% for low, medium, and high concentrations, respectively. The specificity of our extraction technique was good, as assessed by treating 35 urine samples and quantifying estriol by gas chromatography with packed and capillary columns and by liquid chromatography with ultraviolet and fluorometric detection.
Absorbance nephelometry of C1q-precipitable immune complexes: method comparisons and clinical correlations.
Authors: Levinson S S , Goldman J 
Published: January 2020

Abstract
Using a double-beam spectrophotometer, we investigated the clinical utility of a nephelometric method for assaying immune complexes. The complexes were concentrated from serum by precipitation with polyethylene glycol (PEG) and assayed by reaction with C1q. Testing of more than 100 sera showed a Spearman's rank correlation (p) between the present assay and the C1q-binding assay of 0.57, and 0.39 between the Raji cell assay and the present assay. Clinical sensitivity of the methods was not statistically different (p less than or equal to 0.5). Twenty-four of 30 patients with symptoms of disease showed increased concentrations of immune complexes by the present assay; only one of 38 normal individuals showed an increase. In a longitudinal study, we found that the concentrations of immune complexes paralleled clinical changes, indicating good clinical utility. The use of this assay with single-beam analyzers is limited because of the poor aqueous solubility of the PEG precipitate. Ongoing investigations designed to circumvent this problem are described.