bluuebunny/crossref_metadata_2025_split huggingface dataset:
Clinical and laboratory evaluation of a radioimmunoassay kit for measuring the mid-molecule fraction of parathyrin.
Authors: Haver V M , Rinker A D , Ko B M , Tietz N W 
Published: January 2020

Abstract
We report the results of a laboratory and clinical evaluation of a commercial kit procedure (Immuno Nuclear Corp.) for measuring the mid-region of the parathyrin molecule. The estimated dose at 50% binding averaged 130 pmol/L, and the minimum detectable concentration was 14 pmol/L. The within-assay CV was less than or equal to 6.6%, the between-assay CV less than or equal to 12.5%. Relative analytical recoveries of various parathyrin fragments averaged 93% (intact, amino acid residues 1-84), 100% (midregion, 44-68), less than 0.01% (N-terminal, 1-34), and less than 0.01% (C-terminal, 69-84). Correlation of results obtained for 59 patients' samples with a radioimmunoassay for midregion/C-terminal parathyrin performed by the Mayo Medical Laboratory yielded the equation INC = 1.16 (Mayo)-1.94 pmol/L (r = 0.971). Clinical evaluation indicates that the INC results for parathyrin correlate with the diagnoses of patients at least as well as the results obtained with the Mayo assay; in some cases, the INC procedure better distinguishes hyperfunction from normal parathyroid function. The INC procedure can be easily performed in hospital laboratories, with a 4-h turnaround time for results.
Pronounced increases in the concentration of an ovarian tumor marker, CA-125, in serum of a healthy subject during menstruation.
Authors: Mastropaolo W , Fernandez Z , Miller E L 
Published: January 2020

Abstract
CA-125 is a glycoprotein associated with various ovarian tumors. A commercial radioimmunoassay involving a monoclonal antibody is available for it. In our laboratory, a normal-value study was conducted as part of a routine evaluation of this assay. One healthy subject had a serum CA-125 concentration greater than 300 kU/L, more than eightfold the upper limit of normal (35 kU/L). This increase, which coincided with the onset of the menstrual period, subsided to within the normal range by the end of the menstrual cycle. The half-life of CA-125, calculated from this decrease, was 6.4 days. Similar observations were made in the same subject over several menstrual cycles. Results of clinical and ultrasound examinations of the subject for ovarian tumors were negative. No clinical evidence of malignancy was present eight months after the initial discovery of an increased CA-125. None of the other 39 healthy subjects had a CA-125 value greater than 51 kU/L. Five of these subjects had CA-125 determined several times during their menstrual cycles; none exhibited pronounced variations in CA-125 concentrations. Evidently CA-125 can be extremely increased in a healthy woman, and possible effects of the menstrual period on serum CA-125 concentrations should be considered in pre-menopausal patients.
Affinity chromatographic separation of alpha-fetoprotein variants: development of a mini-column procedure, and application to cancer patients.
Authors: Chan D W , Miao Y C 
Published: January 2020

Abstract
This is an affinity chromatographic procedure for separating variants of alpha-fetoprotein in 0.1 mL of serum on a disposable mini-column containing 0.9 mL of concanavalin A-Sepharose, at pH 6.4 and with a flow rate of 5 mL/h. The binding capacity of the column is 52 micrograms. Analytical recovery was 90%. Between-run CVs varied from 2.0% for samples with a high percentage of concanavalin A nonreactive fraction to 13% for samples with a low percentage. The mean proportion of nonreactive alpha-fetoprotein was 13.4% for patients with hepatocellular carcinoma, 62.2% for testicular carcinoma, and 8.9% for nonmalignant liver diseases. This suggests that the alpha-fetoprotein variants could be used to distinguish hepatocellular carcinoma from other carcinomas. Serial determination of the concanavalin A nonreactive fraction in such patients showed a relatively constant percentage. This indicates that monitoring variants in patients with hepatocellular carcinoma throughout their clinical course may not provide useful information additional to that provided by the values for total serum alpha-fetoprotein.
Nephelometry of the kappa/lambda light-chain ratio in serum of normal and diseased children.
Authors: Renckens A L , Jansen M J , van Munster P J , Weemaes C M , Bakkeren J A 
Published: January 2020

Abstract
We determined, immunonephelometrically, the ratio between the two types of light chains of immunoglobulins, kappa and lambda, in serum of 94 children, ages 0.4 to 14 years, with no manifest immunological disorders. Children with an abnormal protein pattern by immunoelectrophoresis show other values for this ratio than do children in this reference group. We also determined the ratios for children with IgA deficiency (I), juvenile rheumatic arthritis (II), and acute lymphoblastic leukemia (III). Children with I show the same kappa/lambda ratios as for the children in the reference group. Children with II also show the same mean kappa/lambda ratios, but a significantly wider range of ratios. In children with III, the ratio during chemotherapy is slightly depressed, significantly lower than after cessation of therapy. All groups--healthy children and patients--show an increase in kappa-chain-bearing immunoglobulins with age, but the concentration of lambda-chain-bearing immunoglobulins remains relatively constant.
SimulTRAC simultaneous radioimmunoassay of thyrotropin and free thyroxin evaluated.
Authors: Gow S M , Caldwell G , Toft A D , Beckett G J 
Published: January 2020

Abstract
We assessed the analytical and diagnostic performance of a dual-isotope RIA for thyrotropin (TSH) and free thyroxin (FT4) in serum. The mean interassay CVs for these analytes were 7.9% and 5.0%, respectively. The mean minimum detection limit for TSH was 0.25 milli-int. unit/L, the mean analytical recovery 110%. There was good agreement with values for TSH and FT4 measured by alternative RIA procedures. Euthyroid patients were well distinguished from those with overt thyroid disease, although there was a small overlap in the case of TSH. Combining the two results better discriminated these categories and identified those patients with subclinical thyroid disease who had abnormal TSH concentrations but FT4 concentrations within reference limits. Euthyroid women taking estrogen-containing oral contraceptives had normal results for TSH and FT4, as did most pregnant women studied. During the third trimester of pregnancy, TSH concentrations of women with low FT4 concentrations were within reference limits. Similarly, euthyroidism was confirmed in patients with low FT4 due to nonthyroidal illness by the simultaneous finding of a normal TSH concentration.
Reversed-phase liquid-chromatographic determination of purine compounds in serum applied to studies of hypouricemia.
Authors: Kojima T , Nishina T , Kitamura M , Kamatani N , Nishioka K 
Published: January 2020

Abstract
With this rapid (20 min), sensitive (0.1 mumol/L), and reproducible reversed-phase "high-performance" liquid-chromatographic (HPLC) method hypoxanthine, xanthine, uric acid, allopurinol (4-hydroxypyrazolo[3,4-d]pyrimidine), and oxypurinol(4,6-dihydroxypyrazolo[3,4-d]pyrimidine) concentrations can be determined simultaneously in de-proteinized serum. We use an Amicon MPS-1 centrifugal ultrafiltration device, then inject the de-proteinized ultrafiltrate into a Toyosoda ODS-120A HPLC column and elute with a mobile phase consisting of potassium phosphate buffer (40 mmol/L, pH 2.2) containing 20 mL of methanol per liter. We used this method to investigate purine metabolism in 10 cases of hypouricemia (uric acid concentration in serum less than 60 mumol/L).
Analytical variance and definition of a reference change as a function of calcium concentration.
Authors: Caudill S P , Boone D J 
Published: January 2020

Abstract
Using data from the Centers for Disease Control (CDC) Proficiency Testing (PT) Surveys, we obtained estimates of repeatability (intralaboratory variability between results on the same material) and reproducibility (interlaboratory variability between results on the same material) for the Technicon SMA 6 (or 12/60) and SMAC 1 (or II) systems used with cresolphthalein complexone methodology to measure serum calcium. The two systems were comparable in terms of short-term (within-day) repeatability, long-term (three to six months) repeatability, short-term (one to two weeks) reproducibility, and long-term (three to six months) reproducibility. The long-term repeatability was essentially the same as the long-term reproducibility. Short-term repeatability, long-term repeatability, and long-term reproducibility increased linearly with increased calcium concentration over the range 1.75 to 2.95 mmol/L; short-term reproducibility showed no significant change over this range. The effect of analytical variance on the definition of a reference change in semiannual calcium measurements was demonstrated.
Measurement of total bilirubin by use of bilirubin oxidase.
Authors: Perry B , Doumas B T , Buffone G , Glick M , Ou C N , Ryder K 
Published: January 2020

Abstract
We used an enzymatic method for measuring total bilirubin in serum. Results by this method varied linearly with bilirubin concentrations to at least 300 mg/L. The day-to-day precision (CV) of the method ranged from less than 1% to about 11% at bilirubin concentrations of 183 and 12 mg/L, respectively. Commonly used anticoagulants, serum preparation materials, and selected drugs had no effect on the apparent bilirubin concentration, but turbidity caused a slight increase and hemoglobin concentrations of 2 g/L resulted in lower values, by as much as 17 mg/L at a bilirubin concentration of 95 mg/L. Patients' results obtained with this enzymatic method were slightly lower than those obtained with methods based on the Jendrassik-Grof principle. The largest differences, seen in samples with high "direct" bilirubin concentrations, can be decreased by measuring the absorbance at 425 nm instead of at 465 nm as recommended by the supplier of the bilirubin oxidase method.
A possible etiological role for ascorbate in calculi formation.
Authors: Chalmers A H , Cowley D M , Brown J M 
Published: January 2020

Abstract
Studies of recurrent stone formers indicated that they have significantly increased urinary oxalate and decreased ascorbate excretions. Results of oral and intravenous administration of ascorbate indicate an enhanced production of oxalate from ascorbate in recurrent calcium stone formers as compared with normal persons and that most of this oxalate is generated in the gut.
Detection of serum proteins by high-pressure gel-permeation chromatography with low-angle laser light scattering, compared with analytical ultracentrifugation.
Authors: Flapper W , van den Oetelaar P J , Breed C P , Steenbergen J , Hoenders H J 
Published: January 2020

Abstract
Human sera were subjected to analytical ultracentrifugation and "high-pressure" gel-permeation chromatography on a system of combined TSK Gel G5000 PW and G3000 SW columns. The chromatographic method produced remarkably superior resolution of the proteins, especially those exceeding 100 000 Da. We calculated the molecular masses of eluted fractions on the basis of their detection by low-angle laser light scattering and their differential refractive index. We discuss the results in relation to the clinical data.
Homogeneous substrate-labeled fluorescent immunoassay for disopyramide in human serum: semi- and fully automated procedures.
Authors: Johnson P K , Messenger L J 
Published: January 2020

Abstract
In this immunoassay for disopyramide in serum, to form the label, disopyramide is covalently attached to a fluorogenic enzyme substrate, 7-beta-galactosylcoumarin-3-carboxylic acid, which is nonfluorescent under the conditions of the assay. Hydrolysis, catalyzed by beta-galactosidase, yields a fluorescent product. As a result of competitive protein binding reactions between drug and label for limited antibody binding sites, this fluorescence is proportional to disopyramide concentration. The assay is sensitive to less than 0.5 mg of disopyramide per liter. Results obtained with either the semi-automated procedure (Ames TDA) or the fully automated (Optimate) procedure correlated well with those obtained by liquid chromatography (r = 0.98 and 0.99). For commercial controls containing various concentrations of the drug, the respective coefficients of correlation were 1.00 and 0.99 for the TDA and Optimate procedures. Within-run CVs for the two procedures were less than or equal to 5.1%, overall CVs less than or equal to 6.5%.
The Coomassie Brilliant Blue method underestimates drug-induced tubular proteinuria.
Authors: Goren M P , Li J T 
Published: January 2020

Abstract
The sensitivity of the Coomassie Brilliant Blue (CBB) procedure differs for different proteins. To investigate the impact of this variability on clinical measurements of proteinuria, we collected urine specimens from patients with glomerular disease or drug-induced tubular nephrotoxicity and compared urinary protein concentrations as determined by the CBB method with those obtained by the biuret method. The CBB method underestimated the protein concentration predicted by the biuret method by as much as eightfold in specimens with low proportions of albumin. Determinations of protein by the CBB method in serially diluted urine specimens from patients with tubular damage also deviated from linearity by as much as twofold for protein concentrations less than 1 g/L. We conclude that CBB binding is relatively insensitive for measuring proteins specifically associated with tubular damage and hence may be inappropriate for clinical use.
Creatinine clearance: enzymatic vs Jaffé determinations of creatinine in plasma and urine.
Authors: Apple F , Bandt C , Prosch A , Erlandson G , Holmstrom V , Scholen J , Googins M 
Published: January 2020

Abstract
We measured creatinine in plasma and urine samples from 17 normal subjects and 10 renally impaired subjects by four different methods: two enzymatic--Ektachem iminohydrolase and Boehringer Mannheim amidohydrolase--and two Jaffé reaction based--Beckman Astra 8 and Technicon AutoAnalyzer I. Creatinine clearances, standardized for body surface area, were also calculated. In both groups of subjects plasma creatinine values were significantly (p less than 0.05) lower, by 3 to 4 mg/L, when measured enzymatically than when measured by the Jaffé reaction. Additionally, creatinine clearances were significantly (p less than 0.05) greater by at least 30 mL/min when calculated from enzymatically measured creatinine values vs Jaffé method values for creatinine. The benefits of lack of interference with enzymatically measured creatinine concentrations and clearances should be assessed in relation to the lack of agreement with long-established (Jaffé) methods for determining creatinine (and inulin) clearances.
Use of 125I-labeled-histamine-cyclosporin C for monitoring serum cyclosporine concentrations in transplantation patients.
Authors: Wong P Y , Cheung M , Yip T K , Mee A V 
Published: January 2020

Abstract
We synthesized an 125I-labeled-histamine-cyclosporin C tracer, to obviate the use of tritiated tracer in radioimmunoassay of cyclosporine. With this tracer, the assay results varied linearly with concentration up to at least 800 micrograms/L. The within-assay CV was 6.6% at 39 micrograms/L, 4.2% at 100 micrograms/L, and 7.0% at 300 micrograms/L (n = 15). The between-assay CV was 10.0, 6.4, and 7.8% for the same respective concentrations. Comparison with an assay involving tritiated tracer (x) showed good agreement of results: y = 3.81 + 0.927x (r = 0.975, n = 604). Analytical recovery ranged from 100 to 106%. We also compared another commercially available radioiodinated tracer ("125Iodocyclosporin"; Immunonuclear Corp.). Our tracer appeared to be more specific for cyclosporine, as determined by assaying chromatographic fractions of bile extract from a patient being treated with cyclosporine. Results with use of our tracer compared favorably with those obtained with the tritiated tracer, and our assay has the advantages of gamma counting vs liquid-scintillation counting.
Mass-spectrometric assay of tocainide in serum.
Authors: Jones C W 
Published: January 2020

Abstract
This mass-spectrometric method for assaying tocainide in serum is specific, reproducible, and sensitive, and sample preparation is rapid. The drug is isolated from serum by liquid-solid extraction on a Baker C18 disposable column. Underivatized drug is separated by elution on a 0.20 mm X 25 m fused-silica capillary column coated with 5% phenylmethylsilicone, then quantified by mass-selective detection (selected ion monitoring). Sample size is 1 mL of serum, but smaller volumes may be used. Mean analytical recovery of the drug from the disposable columns is 75%. Commonly used antiarrhythmics, sedatives, or hypnotics do not interfere. The run-to-run CV at 3.7 mg/L is 4.0%, 3.0% at 10.5 mg/L.
New immunoenzymatic assay for human thyrotropin compared with two radioimmunoassays.
Authors: Pekary A E , Turner L F , Hershman J M 
Published: January 2020

Abstract
We have evaluated a new immunoenzymatic assay for human thyrotropin involving three monoclonal antibodies (Abbott HTSH EIA) and compared the results with those of two conventional nonequilibrium double-antibody radioimmunoassay (RIA) methods: Clinical Assays' RIA and a research RIA (J Clin Endocrinol Metab 1975; 41:676). Mean values for thyrotropin in 100 euthyroid serum samples were similar in the Abbott and Clinical Assays methods, but both sets were significantly higher than those by the research RIA. By all methods, values for hypothyroid patients were clearly higher than values for euthyroid subjects. Results for hyperthyroid and euthyroid subjects were resolved slightly better with the research RIA than with the Abbott kit. The new Abbott assay was far more sensitive than either the Clinical Assays RIA or our research RIA. The correlation of results of the Abbott assay with those of the Clinical Assays and the research RIA exceeded 90% for samples from hypothyroid patients. The Abbott assay replaces radioisotope counting with spectrophotometric detection.
Bilirubin interference with determination of uric acid, cholesterol, and triglycerides in commercial peroxidase-coupled assays, and the effect of ferrocyanide.
Authors: Spain M A , Wu A H 
Published: January 2020

Abstract
We examined the effect of bilirubin on measurement of serum uric acid, cholesterol, and triglyceride in the BMD-8700, Hitachi 705, Multistat III, CentrifiChem, Cobas-Bio, Ektachem 400, aca II, and RA-1000 analyzers. In general, bilirubin interferes more in peroxidase-coupled assays than in either direct methods or those coupled to NAD(P)+. The degree of interference, which can be spectral or chemical, varies and depends on the chromogen and wavelength used. We present data to show the origin and extent of the interference by bilirubin in these systems and demonstrate how ferrocyanide can provide a satisfactory resolution in some cases.
Different diuresis-dependent excretions of urinary enzymes: N-acetyl-beta-D-glucosaminidase, alanine aminopeptidase, alkaline phosphatase, and gamma-glutamyltransferase.
Authors: Jung K , Schulze G , Reinholdt C 
Published: January 2020

Abstract
We studied how much of the lysosomal enzyme N-acetyl-beta-D-glucosaminidase (EC 3.2.1.30) and of the brush-border enzymes alanine aminopeptidase (EC 3.4.11.2), alkaline phosphatase (EC 3.1.3.1), and gamma-glutamyltransferase (EC 2.3.2.2) was excreted in urine over 8 h after a high intake of fluid (22 mL per kilogram of body weight). The hourly excretion of all four enzymes increased with the increasing urine flow rate. The excretion rate of the brush-border enzymes was more markedly influenced than that of N-acetyl-beta-D-glucosaminidase. By relating the enzyme excretion to urinary creatinine we could reduce the variability of brush-border enzyme output and could completely compensate for the effect of diuresis on the excretion of N-acetyl-beta-D-glucosaminidase.
An enzymatic method for calibration of serum lipase assays.
Authors: Hoffmann G E , Neumann U , Hoffmann S , Kaspar P , Weiss L 
Published: January 2020

Abstract
An enzymatic method for the calibration of a turbidimetric lipase assay is described, based on measurement of free fatty acids liberated by the action of lipase. The substrate of the turbidimetric assay is a colipase-containing triolein emulsion. For determination of the free fatty acids a commercial test kit including acyl-CoA synthetase, acyl-CoA oxidase, and peroxidase is used. Intra- and interassay imprecision (CV) is about 5% at above-normal lipase activities, about 10% at normal values. Temperature coefficients are 1.24 and 1.45, respectively, for measurements at 30 and 37 degrees C vs 25 degrees C.
Salivary amylase and pancreatic enzymes in serum after total body irradiation.
Authors: Junglee D , Katrak A , Mohiuddin J , Blacklock H , Prentice H G , Dandona P 
Published: January 2020

Abstract
Amylase increases in serum after total body irradiation (TBI). To investigate whether this increase is ascribable to pancreatic or salivary amylase, or both, we measured the post-irradiation activity concentration of the three major pancreatic enzymes (trypsin, amylase, and lipase) and of salivary-type amylase in serum from six leukemic patients given TBI before bone-marrow transplantation. Salivary amylase increased by as much as 50-fold after TBI, peaking on the first day after the irradiation. The increase was associated with the development of clinical parotitis. Pancreatic trypsin, total amylase, and lipase increased inconsistently and to a much smaller degree. There were no associated clinical features of pancreatitis. Our data show that, at the dose of radiation given to our patients, there is no danger of pancreatitis as a complication, but parotitis is a consistent development after TBI.
Direct measurement of creatine kinase-MB activity in serum after extraction with a monoclonal antibody specific to the MB isoenzyme.
Authors: Vaidya H C , Maynard Y , Dietzler D N , Ladenson J H 
Published: January 2020

Abstract
Fusion of splenocytes from A/J mice immunized by creatine kinase (EC 2.7.3.2)-MB isoenzyme (CK-MB) with SP2/0-Ag14 myeloma cell line generated hybridomas producing monoclonal antibodies specific to CK-MB. One of these monoclonal antibodies ("Conan-MB") was used to develop a direct assay for CK-MB activity. In the assay, serum is incubated for 30 min at room temperature with "Conan-MB" immobilized on latex beads. The beads are then washed, and CK-MB activity bound to the antibody is measured after incubation with CK enzyme reagent for 30 min at 37 degrees C. Results with the assay correlated well (r = 0.997) with those for CK-MB concentration as measured by a two-site immunoassay. Neither CK-MM, CK-BB, mitochondrial CK, nor a hemolysate of erythrocytes interfered. Use of this unique monoclonal antibody allows rapid, precise, and direct determination of CK-MB activity.
Simple method for preparing the cellular intermediate EAC14, and its use for estimation of the second component of complement.
Authors: Asghar S S , Out J , van der Helm H J 
Published: January 2020

Abstract
Sensitized erythrocytes carrying the first and fourth components of complement (EAC14) were prepared by incubating optimally sensitized sheep erythrocytes with normal serum appropriately diluted in Mg2+-free diethylbarbiturate buffer containing Ca2+. EAC14 cells so prepared were found to be suitable for use in estimating the second component of complement (C2) in human serum, and the method is described here.