bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enzyme-amplified immunoassays: a new ultrasensitive assay of thyrotropin evaluated.
Authors: Clark P M , Price C P 
Published: January 2020

Abstract
An enzyme-amplified immunoassay for thyrotropin has been evaluated. The lower limit of detection of the assay (mean + 3 SD of the zero standard) was 0.037 milli-int.unit/L and the precision was good, giving a working range of 0.13-24.0 milli-int.units/L. The accuracy of the assay was good, as judged from analytical-recovery experiments, analysis of external quality-assessment samples and comparison with in-house assays. No significant interferences or cross reactivities were identified. Assay of a 25-microL serum sample on the microtiter plate takes 3 h. Values for healthy subjects ranged from 0.4 to 4.0 milli-int.units/L. For 32 thyrotoxic patients thyrotropin concentrations were clearly suppressed and completely distinct from normal values. Patients taking triiodothyronine also showed lower concentrations. The enzyme-amplified immunoassay may thus be a suitable "front line" test for assessing thyroid function.
Enzyme-linked immunochemical measurement of estrogen receptor in gynecologic tumors, and an overview of steroid receptors in ovarian carcinoma.
Authors: Holt J A , Bolanos J 
Published: January 2020

Abstract
We tested whether a newly available enzyme-linked immunoassay (EIA) validly measures estrogen receptor (ER) in gynecologic tumors. We first documented that ER so measured agreed with results by established radioligand-based assays [dextran-coated charcoal (DCC) and hydroxylapatite (HAP)] for in-house breast carcinomas and for proficiency testing specimens. Then, for gynecologic tumors, we found strong correlations between results for ER as measured by the two methods; e.g., for 27 ovarian carcinomas, r greater than or equal to 0.86. The same was true for ER measured in nine specimens of ovarian carcinoma from women who had undergone chemotherapy: r greater than or equal to 0.94. Radioinert estradiol or serum had no discernible effect on EIA measurements of ER, whereas our DCC assay was rendered uninterpretable. Evidently the EIA validly measures ER in steroidogenic tissues, including ovarian, and also in breast and uterine carcinomas. Clinical management of the latter is now based in part on results of steroid receptor assays. For ovarian carcinomas, ER assay can be helpful for determining the probable primary site of adenocarcinomas of unknown origin, and it is providing a rational basis for development of new diagnostic and therapeutic strategies.
Radial partition immunoassay applied to automated quantification of human choriogonadotropin with use of two monoclonal antibodies.
Authors: Rugg J A , Rigl C T , Leung K , Lamar S L , Welsh M , LeBlanc M , Evans S A 
Published: January 2020

Abstract
We describe a novel application of radial partition immunoassay to quantification of human choriogonadotropin (hCG). In this "sandwich"-type assay, two monoclonal antibodies, specific for different sites on the intact molecule are used. The solid phase consists of tabs of glass-fiber filter paper containing a pre-immobilized antibody specific for the alpha subunit of hCG. The patient's sample is first applied directly to the central "reaction zone" of the tab, allowing hCG to bind to the solid-phase antibody. Then a buffered solution containing enzyme-labeled Fab' fragments of a monoclonal antibody specific for the beta subunit of hCG is applied, initiating "sandwich" formation. Finally, a wash buffer containing a fluorogenic substrate is applied, eluting unbound conjugate to the tab periphery. Bound enzyme conjugate is quantified by measuring the rate of increase in fluorescence. Rates are converted to clinical units by comparison with a stored calibration curve. Elapsed time from sample application to results is less than 8 min. Specific performance characteristics of this assay are reported.
Turbidimetric determination of prothrombin time by clotting in a centrifugal analyzer.
Authors: Gogstad G O , Dahl K H , Christophersen A , Bjerke A 
Published: January 2020

Abstract
Two thromboplastin reagents ("Thrombotest" and "Normotest Automated") were used in evaluation of an automated method for determination of prothrombin time based on turbidimetric measurement of clot formation in a centrifugal analyzer. We used 60 plasma samples from patients with various diseases or being treated with oral anticoagulant and 16 normal plasma samples. Prothrombin times were calculated by a computer connected to the analyzer, a reading being made at either a certain per cent increase in total absorbance or a fixed absorbance increase. Both correlated well with the manual method (r = 0.98-0.99). The reading points best fitting the manually obtained data were estimated by minimizing the residual sum of squares in regression analyses performed at various absorbance increases. The per cent reading was better in this respect. Normotest Automated could be nearly perfectly related to the manual method, whereas Thrombotest showed a (negligibly) small deviation. Reproducibility was good within run (CV less than or equal to 3.2%) as well as between batch of the reagents, as assessed from variation in INR (CV less than or equal to 4.9%). We conclude that turbidimetry of clot formation may be validly used in automation of the prothrombin-time test. The equipment needed and the total time per analysis are about as for chromogenic substrate methods, but reagent cost is considerably lower.
Two-monoclonal-antibody sandwich-type assay for thyrotropin, with use of an avidin-biotin separation technique.
Authors: Odell W D , Griffin J , Zahradnik R 
Published: January 2020

Abstract
We have developed a sensitive, specific, noncompetitive, sandwich-type radioimmunoassay for human thyrotropin (hTSH), which can be performed in 30 min. The assay involves two monoclonal antibodies, selected for high affinity and specificity and also for reaction against antigenic sites on hTSH that are distal from each other. One of these antibodies is labeled with 125I; the other is conjugated covalently to biotin. Polystyrene beads were also conjugated covalently to biotin. After conjugation, the beads were incubated with avidin. These beads represent a rapid, simple method for separating hTSH-bound antibody from free antibody. The biotin-antibody-hTSH-125I-labeled antibody complexes bind to the beads and hTSH concentration is directly related to counts per minute. This assay can detect hTSH at a concentration of 0.06 milli-unit/L in serum.
Abnormal composition of apoproteins C-I, C-II, and C-III in plasma and very-low-density lipoproteins of non-insulin-dependent diabetic Chinese.
Authors: Pan X R , Cheung M C , Walden C E , Hu S X , Bierman E L , Albers J J 
Published: January 2020

Abstract
Apoprotein (apo) C-I, C-II, and C-III were measured in plasma from 35 white American non-diabetic subjects. The mean concentrations (mg/L) in plasma from normolipidemic and hypertriglyceridemic subjects, respectively, were apo C-I, 78 and 311; apo C-II, 37 and 200; and apo C-III, 98 and 529. These concentrations were strongly correlated with the concentrations of plasma triglyceride (TG). We also measured these apoproteins in 23 Chinese non-insulin-dependent diabetic patients (13 men, 10 women) and in eight male and 10 female non-diabetic Chinese controls. The male diabetics had significantly lower concentrations of apo C-I in plasma, and lower apo C-I/TG, apo C-II/TG, apo C-III/TG, and apo C-I/C-III ratios than did the controls. The female diabetics had significantly higher apo C-II concentrations than the controls. The median value for plasma glucose during fasting was 1400 mg/L in the male diabetic subjects, similar to the 1370 mg/L value in female diabetics. Therefore, the higher concentrations of very-low-density lipoprotein in male diabetics may not reflect hyperglycemia per se.
Separation of an inhibitor of erythropoiesis in "middle molecules" from hemodialysate from patients with chronic renal failure.
Authors: Saito A , Suzuki I , Chung T G , Okamoto T , Hotta T 
Published: January 2020

Abstract
A "middle molecule" inhibitor of erythropoiesis in patients with chronic renal failure was separated from a large amount of hemodialysate. Hemodialysate was passed through Amberlite XAD-4 resin, Sephadex G-50 gel, and DEAE-Sephadex A-25, followed by reversed-phase liquid chromatography. The erythroid colony assay (CFU-E) was used to detect the inhibitory effect of the sample solution. Certain fractions from the DEAE-Sephadex A-25 column showed a dose-related inhibition of CFU-E formation as great as that of standard spermine. The inhibitory effect of these fractions decreased to the control value after proteolytic digestion. The inhibitor was eluted from the liquid-chromatographic column by a solvent gradient containing 390 to 425 mL of methanol per liter. These results suggest there is an inhibitor of CFU-E with a relative molecular mass of 1000 to 10 000 and an active site composed of peptide. This technique may prove useful for separation of the inhibitor of erythropoiesis in uremic body fluid.
Minimizing between-kit variability in immunoassay for carcinoembryonic antigen by use of a common standard.
Authors: Zucchelli G C , Pilo A , Chiesa M R , Masini S , Baccini C 
Published: January 2020

Abstract
Between-laboratory agreement of CEA determinations collected in a multicenter study has been substantially improved (CV decreased from 60.4 to 21.6%) by converting the results from mass concentration units (ng/mL) of local kit standards to int. units/L of the international standard first IRP 73/601. Conversion factors for the kits most used were computed, during the same survey, from results of two analytical-recovery experiments in which control samples, supplemented with the international standard, were analyzed by participating laboratories (n = 96).
Liquid-chromatographic assay of urinary vanillylmandelic acid and homovanillic acid, with clean-up by on-column injection of acetonitrile or methanol.
Authors: Kodama K , Yamanaka K , Nakata T , Aoyama M 
Published: January 2020

Abstract
To separately measure vanillylmandelic acid (VMA) and homovanillic acid (HVA) in urine, the sample is diluted 10-fold with 50 mmol/L phosphoric acid, then exactly 5 microL is injected directly onto a 50 X 4.6 mm column of Nucleosil 3C18. Samples can be injected at 5-min intervals because all peaks after these compounds of interest are washed away. VMA is eluted from the column after 2.8 min with 50 mmol/L phosphate buffer, pH 2.2, and measured by electrochemical detection. All peaks eluting after VMA are washed away together, by injection of 50 microL of acetonitrile onto the column. HVA is eluted from the column after 3.3 min with a 100/10 (by vol) mixture of the phosphate buffer and acetonitrile. All later-eluting peaks are washed away together, by injection of 50 microL of methanol onto the column. Analytical recoveries of VMA and HVA were 98.5% and 100.6%, respectively; the CVs for various concentrations of either in urine were about 3%.
Immunoradiometric assay with use of magnetizable particles: measurement of thyrotropin in blood spots, to screen for neonatal hypothyroidism.
Authors: Waite K V , Maberly G F , Ma G , Eastman C J 
Published: January 2020

Abstract
We adapted a commercial immunoradiometric assay (IRMA) to measure thyrotropin in filter-paper blood spots. Two 3-mm blood spots are used for each standard and sample. These are incubated for 2 h with radiolabeled antibody and for 30 min with magnetic antibody, followed by a 10-min separation procedure. Assay sensitivity is 6 milli-int. units/L. Coefficients of variation (precision profile of the standard curve) ranged from 4.3 to 9.6%. The coefficient of correlation (r) between thyrotropin concentrations in the blood spots and in serum was 0.93. Pre-elution of the blood spots is necessary for short incubation time. Short incubation time, little need for specialized equipment, the high precision and sensitivity characteristic of IRMA, and ease of collection, transport, and storage of the blood-spot samples make this assay suitable for neonatal hypothyroid screening.
Fluorescence topography in biology. III: Characteristic deviations of tryptophan fluorescence in sera of patients with gynecological tumors.
Authors: Leiner M J , Schaur R J , Desoye G , Wolfbeis O S 
Published: January 2020

Abstract
The near-ultraviolet region of the total fluorescence (excitation-emission matrix) of human serum reflects essentially the fluorescence of protein-bound tryptophan. We examined topographically the tryptophan fluorescence of human serum. In comparison with fluorescence topograms from sera of healthy donors, sera of patients with gynecological malignancies showed significantly different patterns of tryptophan fluorescence, the major deviations being at 325 and 365 nm. In healthy donors, the tryptophan fluorescence intensity at 365 nm, expressed as percent of the maximum fluorescence intensity (i.e., at 337 nm) varied little, but was markedly lower for sera from patients with malignancies. We found no clear correlation between the extent of the fluorescence deviations and the relative concentration of the protein fractions as determined by electrophoresis. Furthermore, we could rule out inflammation in tumor patients as an explanation for this effect.
Occurrence of normal circulating proalbumin in a hemophilic A patient after acute hepatitis related to the delta virus.
Authors: Fine J M , Allain J P , Rochu D , Marneux M 
Published: January 2020

Abstract
Circulating proalbumin in humans has been described in two distinct events: genetic variants of proalbumin related to mutations at the cleavage site, and normal proalbumin related to an abnormal cleaving enzyme system. We report a case of acquired proalbuminemia that appeared after an acute episode of hepatitis related to the delta agent, in a chronic carrier of hepatitis B virus. This component, not present in normal plasma, was identified as proalbumin by immunological methods. It was indistinguishable from the molecule normally present in hepatocytes as judged by electrophoretic mobility, limited susceptibility to tryptic digestion, and its inability to bind labeled Ni. We suggest that this release of proalbumin is related to the concurrent presence of both hepatitis B and delta virus in some of the infected hepatocytes.
Factors associated with microhematuria in asymptomatic young men.
Authors: Froom P , Gross M , Froom J , Caine Y , Margaliot S , Benbassat J 
Published: January 2020

Abstract
The prevalence of asymptomatic microhematuria (two to four or more erythrocytes per high-power field) in 1341 male Air Force personnel was 5.4%. The most powerful predictor of microhematuria (nearly 15-fold increased prevalence) was a history of recurrent microhematuria during the previous five years. Recurrent microscopic hematuria was present in 14.5% (8/55) of men with a history of urethritis, accounting for 26% (8/31) of the cases of recurrent microscopic hematuria. The prevalence of microhematuria was not affected by physical exercise, flight duty, or sexual intercourse during the 24 h preceding the urinalysis.
Choice of immunoglobulin G purification method in assays for antibodies to the thyrotropin receptor.
Authors: Brown R S , Kertiles L P , Kleinmann R E 
Published: January 2020

Abstract
Activity of autoantibodies to the thyrotropin receptor in the serum of patients with active Graves's disease was compared when the patients' IgG was purified by three different procedures: ammonium sulfate precipitation (I), a modified batch diethylaminoethyl cellulose method (II), and affinity chromatography on Protein A-Sepharose CL-4B (III). IgG extracted by I was significantly less potent in inhibiting binding of 125I-labeled thyroid membranes than that prepared by either II or III, and was significantly less effective than II in stimulating adenyl cyclase activity in thyroid membrane. Thyroglobulin, a serum protein whose concentration is increased in patients with various thyroid diseases, was coprecipitated in amounts sufficient to significantly inhibit binding only when method I was used, but not with either of the other two procedures. Evidently method I is inferior to either of the other two when used for purification of autoantibodies to the thyrotropin receptor. Method II used in this study, being faster and more economical than I and of equivalent efficacy, is a feasible alternative method for clinical use.
Increased creatine kinase MB in the absence of acute myocardial infarction.
Authors: Pierce G F , Jaffe A S 
Published: January 2020

Abstract
Although measurement of CK-MB is a very sensitive, specific, and cost-effective test for use in diagnosis or exclusion of acute myocardial infarction, it should not be used as the sole diagnostic indicator, and all positive values must be critically analyzed to exclude other causes of increased values in serum. This is particularly important when the population being tested consists of patients with multiple medical problems, with low to medium probability of myocardial infarction, and without clinical or other biochemical (i.e., LDH 1) evidence of acute myocardial infarction. When the temporal pattern and absolute CK-MB values are considered together with the patient's clinical status, the diagnostic specificity is dramatically increased. In addition, one must be familiar with the limitations of individual assay systems in order to exclude method-related artifactual values.
A simple radial immunodiffusion method for assay of beta 2-microglobulin in serum.
Authors: Wu J T , Clayton F , Myers S , Knight J 
Published: January 2020

Abstract
In this method for clinical measurement of beta 2-microglobulin, a 10 g/L agarose gel containing anti-beta 2-microglobulin is used, with subsequent staining with Coomassie Blue. Although the method is slow (requiring 30 h), it is inexpensive, reliable, and accurate over the range of 1 to 10 mg/L, and is useful in the determination of beta 2-microglobulin in serum and cerebrospinal fluid. A modified procedure in which staining with silver is used may be sufficiently sensitive for the clinical assay of urine.
Two-site enzyme immunoassay for alpha-fetoprotein in dried-blood samples collected on filter paper.
Authors: Tsao D , Hsiao K J , Wu J C , Chou C K , Lee S D 
Published: January 2020

Abstract
This is a method for measuring alpha-fetoprotein (AFP) in eluates of dried-blood samples on filter paper by use of a simple, sensitive two-site enzyme immunoassay. The spot, 6 mm in diameter (equivalent to about 12 microL of whole blood), is incubated overnight with alkaline phosphatase conjugated to rabbit anti-AFP antibody in a tube containing a polystyrene bead coated with mouse monoclonal antibody to AFP. After the beads are washed the enzyme activities associated with them are determined colorimetrically, with p-nitrophenyl phosphate as substrate. The measurable range of AFP is from 9 to 900 micrograms per liter of plasma. AFP in the dried-blood spot as determined by this method correlated well with the AFP value for serum from the same blood sample as determined by radioimmunoassay (r = 0.957, p less than 0.001). Preliminary studies in which we used this method with 242 healthy blood donors and 60 patients with hepatocellular carcinoma indicate that it may be suitable for use in mass screening for hepatocellular carcinoma in high-risk populations.
Analytical evaluation of four sensitive assays of thyrotropin, including effects of variations in patient sampling.
Authors: Kreutzer H J , Tertoolen J F , Thijssen J H , der Kinderen P J , Koppeschaar H P 
Published: January 2020

Abstract
Four immunometric kits for thyrotropin with detection limits below 0.1 milli-int. unit/L were evaluated with respect to accuracy, precision, specificity, matrix effects, and high-dose "hook" effect. We also studied variations of values related to the patients' sex and age and time of the day and season when samples were collected. Correlation among the four methods was excellent, except for a few samples, and the interference in these samples could be abolished by adding mouse serum or "suppression medium." These phenomena can also be expected to occur in other immunometric assays involving monoclonal antibodies. With some modifications all tests are suitable for a clinical study of the usefulness of the thyrotropin assay as a primary test for thyroid function.
Simultaneous quantification of erythrocyte zinc protoporphyrin and protoporphyrin IX by liquid chromatography.
Authors: Bailey G G , Needham L L 
Published: January 2020

Abstract
A simple, rapid, specific, and sensitive isocratic "high-performance" liquid-chromatographic procedure is described for measuring protoporphyrin (PPIX) and zinc protoporphyrin (ZPP) in erythrocytes. A 30-microL whole-blood sample is treated with a solution of formic acid, deproteinized with acetone, and centrifuged. A 20-microL aliquot of the supernate is injected into a system consisting of a stationary phase of mu-Bondapak C18 and a mobile phase of acetone, methanol, water, and formic acid. ZPP and PPIX are detected fluorometrically (lambda ex = 417 nm, lambda em = 635 nm) within 6 min. The range of linearity extends beyond 10 mg/L for ZPP and 580 micrograms/L for PPIX. The detection limits for ZPP and PPIX are 11.9 micrograms/L (6.93 pg) and 2.55 micrograms/L (1.485 pg), respectively. The precision for ZPP and PPIX determinations averaged 2.86 and 5.59%, respectively, for within-day CVs and 4.98 and 8.14, respectively, for among-day CVs. Analytical recoveries averaged 97.2% for ZPP and 101.5% for PPIX. Interferences in the form of fluorescent quenching of ZPP and PPIX by hemin are avoided by chromatographic separation. We also used this method to determine the purity of commercially prepared ZPP, and compared the results obtained with this method with those from an extraction method.
Pregnancy-specific beta 1-glycoprotein in serum in monoclonal gammopathies: relationship with serum beta 2-microglobulin, and cellular origin.
Authors: Fagnart O C , Tasiaux N , Masson P L 
Published: January 2020

Abstract
Pregnancy-specific beta 1-glycoprotein (SP1) was assayed by particle-counting immunoassay in serum from 86 healthy blood donors and 236 patients with various types of gammopathy. A concentration of 1 microgram/L was taken as the upper normal limit. Abnormally high values were found in one of 10 patients with monoclonal gammopathy of undetermined significance, in 65% of 152 patients with multiple myeloma, in 84% of 64 patients with Waldenström's macroglobulinemia, and in seven of 10 patients with monoclonal gammopathies associated with other myeloproliferative disorders. In a study of 90 myeloma patients, the SP1 value correlated (p less than 0.001) with the concentration of beta 2-microglobulin in serum, a value which had been corrected for possible renal dysfunction, but not with the concentration of the monoclonal component. SP1 was detected by direct immunofluorescence in myeloma cells of bone-marrow smears from six of 10 patients with myelomatosis. These six patients had serum SP1 values greater than 1 microgram/L, whereas the four patients with fluorescence-negative myeloma cells had SP1 values less than 1 microgram/L.