bluuebunny/crossref_metadata_2025_split huggingface dataset:
Relationship of potassium and magnesium concentrations in serum to cardiac arrhythmias.
Authors: Boyd J C , Bruns D E , DiMarco J P , Sugg N K , Wills M R 
Published: January 2020

Abstract
Low concentrations of potassium and magnesium in serum have been implicated in cardiac arrhythmias; the importance of mild hypokalemia or hypomagnesemia is uncertain. To investigate possible associations among use of diuretics, the concentration of these ions in serum, and the onset of clinically important arrhythmias, we reviewed records of 103 patients admitted to our Coronary Care Unit during three months and found mild to moderate hypokalemia and hypo- magnesemia in 18 and 24%, respectively. The significant correlation between the concentrations of magnesium and potassium in serum at admission (r = 0.27, p less than 0.007) remained constant in patients, whether they were receiving diuretics or not. Potassium concentrations were significantly lower (p less than 0.05) in patients receiving diuretics (3.93 mmol/L) than in those who were not (4.21 mmol/L), but the mean concentrations of magnesium did not differ significantly. Except for myocardial infarction, no single variable or combination of variables was highly predictive of cardiac arrhythmias in these patients. We conclude that there is no strong predictive relationship between mildly decreased concentrations of magnesium or potassium in serum and onset of cardiac arrhythmias.
Values of the U.S. National Reference Serum for human antibodies to native DNA obtained with commercial immunoassays for anti-DNA in systemic lupus erythematosus.
Authors: Berne B H , Galland K T , Welton R C 
Published: January 2020

Abstract
The Arthritis Foundation and the Centers for Disease Control have recently prepared a "U.S. National Reference Serum" for human antibodies to native DNA. We tested this serum with 13 commercial assays for antibodies to native DNA, to permit comparisons of the values obtained in each test. Titers ranged from 10 to 2560 in Crithidia luciliae immunofluorescence assays. The serum produced 794 int. units/mL in the Cordis ELISA assay, 136 Amersham units/mL in a radioimmunoassay, and 88 FIAX units in a fluorometric immunoassay. These results can be used for interlaboratory comparisons of differing methodologies for measuring anti-DNA.
Six approaches to routine quantification of human monoclonal immunoglobulin M compared.
Authors: Pontet F , Auget J L , Rousselet F 
Published: January 2020

Abstract
Six routine techniques for the determination of monoclonal IgM are compared: standard electrophoresis, the Technicon AIP system, Hyland laser nephelometry, Beckman Immunochemistry System, Behring laser nephelometry, and radial immunodiffusion. The data are evaluated by use of a nonparametric statistical analysis of variance by ranks (Friedman test) and Wilcoxon's test. The 27 sera containing monoclonal IgM that we studied yielded different results by the various techniques. Sera from a "reference" population of 15 subjects having above-normal polyclonal IgM yielded identical results for all techniques. These statistical findings agree with the biophysical mechanisms involved in the various ways of quantifying IgM. We conclude that these different systems are equivalent for estimating polyclonal IgM, but cannot (and should not) yield identical values when used in monoclonal IgM evaluations. Results for monoclonal IgM must be interpreted in terms of the molecular forms and immunological specificities of the assayed IgM.
Estimation of free thyroxin with a new thyroxin analog and a porous-glass solid phase.
Authors: Witherspoon L R , Shuler S E , Gilbert S S 
Published: January 2020

Abstract
We evaluated a new thyroxin analog-based assay for free thyroxin (FT4) (Corning Medical), finding it technically simple and precise (between-assay CVs of 3.3 and 4.2% for FT4 concentrations of 12 and 25 ng/L, respectively). We measured FT4 in a total of 325 serum samples from euthyroid patients; patients receiving replacement thyroxin; patients receiving estrogens or who were pregnant; hyperthyroid, hypothyroid, and non- thyroidally ill patients; and patients receiving salicylates, phenytoin, or heparin. This assay clearly identified hyper- and hypothyroid patients, and produced similar results in euthyroid patients with above-normal, normal, or low concentration of thyroxin-binding globulin. Results in some non-thyroid-illness patients and patients receiving salicylates or phenytoin were low compared with euthyroid patients receiving no medications, but the diagnostic accuracy of the Corning FT4 assay exceeded that of another analog-based assay (Amersham) in these particular groups. We believe the new Corning analog FT4 assay offers an attractive alternative to other commercial FT4 systems.
Anion-exchange chromatographic determination of bromide in serum.
Authors: Miller M E , Cappon C J 
Published: January 2020

Abstract
In this liquid-chromatographic method for the determination of bromide in human serum, an important and unique feature is pre-analysis ultrafiltration of the sample, which effectively removes proteins. The chromatographic system consists of an anion-exchange column (Whatman Partisil SAX 10-micron particles), an isocratic phosphate-buffered mobile phase, and ultraviolet detection at 195 nm. The absolute detection limit, 0.6 ng of bromide, makes this method the most sensitive assay for serum bromide yet reported. The day-to-day CV ranged from 1.6% to 4.9%. Analytical recovery of bromide added to serum samples ranged from 96.2% to 108.8%. Data on bromide in serum are presented for adults and newborns and for adults given bromide orally.
A new approach to photometry of glycated hemoglobin in human blood.
Authors: Deeg R , Schmitt U , Rollinger W , Ziegenhorn J 
Published: January 2020

Abstract
This new approach to measurement of glycated hemoglobin (Hb A1) is a three-step procedure involving (a) conversion of oxyhemoglobin into NO-hemoglobin by sodium dithionite and sodium nitrite in the presence of inositol hexaphosphate; (b) incubation with haptoglobin, which preferentially binds glycated hemoglobin; and (c) determination of the hemoglobin/haptoglobin complex by its peroxidase activity in acid buffer. The procedure is suitable for automated analysis with instruments that are capable of adding a starting reagent. We describe preliminary adaptations for the Abbott VP and Hitachi 705 analyzers and demonstrate the correlation of results with Hb A1 concentrations determined by ion-exchange chromatography.
"Nonspecific" Increases in Plasma Immunoreactive Calcitonin in Healthy Individuals: Discrimination from Medullary Thyroid Carcinoma by a New Extraction Technique
Authors: Body Jean-Jacques , Heath Hunter 
Published: January 2020

Abstract
Vol. 30
After pp. 513-514 of the April issue were proofed and released to the printer, the text was scrambled in the process of adjusting layout. We are reprinting the pages here as they should have appeared. The printer apologizes for any confusion and inconvenience this may have caused the readers and authors of this article.
Automated amidolytic method for determining heparin, a heparinoid, and a low-Mr heparin fragment, based on their anti-Xa activity.
Authors: ten Cate H , Lamping R J , Henny C P , Prins A , ten Cate J W 
Published: January 2020

Abstract
Using the chromogenic substrate S-2222, we have optimized and automated an amidolytic assay for heparin. The assay is based on the detection of anti-Xa activity generated by heparin in plasma. The method is reproducible (intra- and interassay CVs of 2.4 and 3.3%, respectively) and reliable in antithrombin III-deficient plasma. Results of this assay, obtained for plasma samples from patients and volunteers treated with heparin, correlate well (r = 0.899) with those of the test for activated partial thromboplastin time. Upon administration of a low-Mr heparinoid (Org 10172) and heparin fragment ( Kabi 2165), however, the activated partial thromboplastin time failed to detect anticoagulant activity, whereas the chromogenic heparin assay revealed anti-Xa activity. This automated amidolytic assay for heparin is therefore suitable not only for monitoring standard therapy with heparin but also for measuring the activity of recently developed heparin fractions.
A new assay for rheumatoid factor.
Authors: Giaever I , Keese C R , Rynes R I 
Published: January 2020

Abstract
This solid-phase immunoassay for detection of rheumatoid factor involves a specially prepared indium surface that renders protein layers visible and therefore does not require tagged protein. Using appropriate discriminatory values, we found agreement with results of a standard latex-fixation test in controls and patients with rheumatoid arthritis. About half of the patients with rheumatoid arthritis that were seronegative by this latex fixation test had positive tests by the present assay. Rheumatoid factor of both the IgM and IgA class may be easily assessed.
Indophenol method for acetaminophen in serum examined.
Authors: Novotny P E , Elser R C 
Published: January 2020

Abstract
We show that an indophenol-based colorimetric method for acetaminophen (Clin Toxicol 15: 67-73, 1979) has less than maximal sensitivity because of (a) incomplete hydrolysis, related to suboptimal acid concentration; (b) suboptimal hydrolysis time; and (c) possible deterioration of the ammonium hydroxide reagent after 2.5 months. We have modified the method by optimizing duration of hydrolysis and color development. Results by the method correlate linearly with acetaminophen concentrations to 250 mg/L (1.66 mmol/L). Moreover, the modified method is free from interference by compounds in serum from uremic patients.
Protein-enhanced fluorescein chemiluminescence used in an immunoassay for rubella antibody in serum.
Authors: Shapiro R , Chan J , Pierson A , Vaccaro K , Quick J 
Published: January 2020

Abstract
The chemiluminescence of fluorescein derivatives is greatly enhanced when they are conjugated to proteins. We exploited this property in devising a chemiluminescence immunoassay for rubella antibodies. In this sequential "sandwich"-type assay, tubes coated with rubella antigen are used for antibody separation and goat antibody to human IgG conjugated with fluorescein isothiocyanate is used for detection of bound rubella antibodies.
Effects of azotemia on results of the boronate-agarose affinity and ion-exchange methods for glycated hemoglobin.
Authors: Scott M G , Hoffmann J W , Meltzer V N , Siegfried B A , Chan K M 
Published: January 2020

Abstract
We evaluated the effect of azotemia on results for glycated hemoglobin as measured by a boronate-agarose affinity method and an ion-exchange chromatographic procedure with saline preincubation and found a good correlation. However, values for glycated hemoglobin in samples from nondiabetic patients with various degrees of azotemia were consistently higher with the ion-exchange column procedure (mean, 8.5%) than with the boronate affinity method (mean, 6.2%). The latter method may thus be preferred for monitoring glycated hemoglobin in diabetic patients with impaired renal function.
Liquid-chromatographic determination of indomethacin in blood from newborns with patent ductus arteriosus.
Authors: Ou C N , Frawley V L 
Published: January 2020

Abstract
This rapid, accurate "high-performance" liquid-chromatographic procedure is intended for measuring indomethacin in serum from neonates who are receiving indomethacin for symptomatic patent ductus arteriosus. Indomethacin and an internal standard (flufenamic acid) are extracted from serum or plasma with chloroform or diethyl ether at pH 5.0. For the chromatography we used a Waters' Radial Compression Separation System (Radial-NOVA PAK C18 reversed-phase column) and a mobile phase of methanol/sodium acetate buffer (10 mmol/L, pH 3.6), 70/30 by vol. The column effluent is monitored at 254 nm. Both indomethacin and flufenamic acid are eluted within 7 min. Indomethacin can be detected in concentrations as low as 50 micrograms/L, in 100-microL samples. Response varies linearly with indomethacin concentration to at least 2 mg/L. Analytical recovery is 75%; relative recovery is 100%. Precision is excellent. Using this method, we were able to improve the success rate for pharmacological management of symptomatic patent ductus arteriosus, especially in neonates with fast clearance rates for the drug.
Influences of specimen processing and storage conditions on results for plasma ammonia.
Authors: Howanitz J H , Howanitz P J , Skrodzki C A , Iwanski J A 
Published: January 2020

Abstract
Ammonia concentrations in plasma may increase because of contamination and deterioration of blood components during specimen handling and storage. Using replicate specimens from healthy volunteers, we studied influences of specimen processing and storage procedures on ammonia measurements made with a self-contained reagent system. Under some conditions, ammonia concentrations more than doubled. The use of nonhemolyzed plasma specimens and prompt centrifugation, separation of plasma, and ammonia determination apparently were important in avoiding such increases, the duration of contact between plasma and cells being the most important factor. Lower temperatures had minimal effect on whole-blood storage and centrifugation, but retarded increases in ammonia in stored plasma. We conclude that procedures for collection and storage of specimens for ammonia determinations should be standardized and strictly observed.
Hyperviscosity caused by hyaluronic acid in serum in a case of Wilms' tumor.
Authors: Wu A H , Parker O S , Ford L 
Published: January 2020

Abstract
We describe the case of a three-year-old girl with Wilms' tumor, whose serum showed at least a fivefold increase in relative viscosity although concentrations of albumin and immunoglobulins were normal. An unusual electrophoretogram of serum protein prompted further investigation. The increased viscosity was caused by the presence of high concentrations of hyaluronic acid, a glycosaminoglycan normally not detectable in serum.
Receptors, antibodies, and disease.
Authors: Blecher M 
Published: January 2020

Abstract
Abnormal antibody production is now recognized as the basis of specific endocrine and neurological diseases and their complications. Among the autoimmune diseases, the best understood from a mechanistic point of view are myasthenia gravis, Graves' disease, several variants of insulin resistance, and a variant of bronchial asthma. In each of these human disorders, the clinical symptoms can be traced to the actions of antireceptor antibodies produced by a deranged immune system. The autoantibodies produced in these diseases are functionally heterogeneous. They may produce the clinical symptoms of hormone or neurotransmitter insufficiency either by blocking the binding of these agents to target cell surface receptors or by accelerating the internalization and degradation of these receptors. In other cases, the autoantibodies may produce the clinical signs of hormone excess by mimicking the actions of the hormone, in an uncontrollable fashion. In some cases, functionally different types of autoantibodies will appear in the same patient at different stages of the disease. For all of these autoantibodies, of whatever function, assays for their presence in serum are available, in forms suitable for clinical chemists, as well as for researchers; these will be described in this review. In addition to the known anti-receptor autoimmune diseases, there are a large number of other autoimmune diseases for which there is fragmentary evidence that their clinical symptoms have an anti-receptor autoantibody etiology. Several examples of this group will be discussed, and assays suitable for establishing the presence of anti-receptor antibodies in the sera of such patients will be provided. The disorders to be considered are: type I diabetes mellitus, chronic atrophic gastritis, autoimmune Addison's disease, autoimmune hypoparathyroidism, type II pseudohypoparathyroidism, resistant ovary syndrome, connective tissue diseases, and the HLA-B8/DR3 antigen haplotype as a potential marker for autoimmune diseases of the anti-receptor type.
Theoretical aspects of one-point calibration: causes and effects of some potential errors, and their dependence on concentration.
Authors: Kemp G J 
Published: January 2020

Abstract
The potential errors of the one-point calibration technique are described mathematically. I examine the theoretical causes and effects of analytical errors in absorbance and of errors in determining calibration concentration, and discuss techniques for minimizing their impact. The dependence of these errors on the calibration concentration and on the size of the result is considered, and some conclusions are drawn about the choice of calibration concentration.
Familial dysalbuminemic hyperthyroxinemia: a study of four probands and the kindred of three.
Authors: Scottolini A G , Bhagavan N V , Oshiro T , Powers L 
Published: January 2020

Abstract
We investigated four probands, and the kindred of three, with familial dysalbuminemic hyperthyroxinemia, using the one- and two-step tests for free thyroxin and other thyroid-function tests. The results indicate that this is an autosomal dominant trait. The discovery of eight cases in our patient population, which represents about 4% of our hyperthyroxinemic patients (8/320), during eight months indicates that this aberration is more common than suspected. Its importance lies in the misinterpretation of test results and the consequent inappropriate treatment for thyrotoxicosis.
Multilayer-film analysis for urea nitrogen in blood, serum, or plasma.
Authors: Ohkubo A , Kamei S , Yamanaka M , Katsuyama H , Iwata Y , Sekikawa N 
Published: January 2020

Abstract
Two types of multilayer-film slides for measurement of urea nitrogen in blood are reported here: one for whole-blood samples, the other for plasma or serum. Urea nitrogen concentrations in plasma are determined almost immediately, without preparation of reagents or centrifugation of blood samples. Because the sample volume applied to the slide is not critical, reliable results are quickly obtained by the neophyte.
Intercomparison of seven radioimmunoassay kits and a fluorescence polarization immunoassay kit for digoxin.
Authors: Erickson K A , Green P J 
Published: January 2020

Abstract
Samples from 33 patients being treated with digoxin and three concentrations of control material were analyzed for this drug by use of seven radioimmunoassay (RIA) kits and an automated fluorescence polarization immunoassay (FPIA) system. CVs ranged from 2.4 to 6.4% for the FPIA system and from 4.6 to 7.4% for two RIA methods. In the analysis of between-method variability of RIA kits, CVs ranged from 6.1 to 33.2%. We compared each RIA kit with the other six RIA kits (I), as well as each RIA kit with the FPIA system (II). Correlation coefficients were greater than or equal to 0.96 in all cases. Slopes ranged from 0.82 to 1.20 for comparison I and from 0.86 to 1.01 for comparison II. For the FPIA system, analytical recovery of digoxin ranged from 94 to 104%. For the RIA methods we examined, analytical recoveries ranged from 113 to 135%. Analysis time is shorter and precision is greater for the FPIA system than for the RIA methods.
Free and total putrescine in cerebrospinal fluid quantified by reversed-phase liquid chromatography.
Authors: Heideman R L , Fickling K B , Walker L J 
Published: January 2020

Abstract
This is a simple, rapid, sensitive method for routine quantification of the polyamine putrescine (1,4-diaminobutane) in cerebrospinal fluid. Sample preparation involves protein precipitation, acid hydrolysis for 18 h (if total putrescine is to be measured), pre-column derivatization with o-phthalaldehyde, and extraction into acetonitrile. The derivative is separated and quantified by "high-performance" liquid chromatography on a reversed-phase C18 radial-compression column. A single chromatographic run takes less than 18 min. Putrescine concentrations as low as 50 nmol/L in cerebrospinal fluid can be detected.
The Ektachem clinical chemistry slide for simultaneous determination of unconjugated and sugar-conjugated bilirubin.
Authors: Wu T W , Dappen G M , Spayd R W , Sundberg M W , Powers D M 
Published: January 2020

Abstract
Using dual-wavelength spectrometry, we have refined the mordant-based bilirubin slide method (Clin Chem 28:2366-2372, 1982) to co-detect unconjugated bilirubin (Bu) and its sugar conjugates (Bc) in 10 microL of serum. The assay is based on three principles: (a) mono- and diconjugated bilirubins behave spectrally like one fraction (Bc) when bound to the mordant, (b) Bu and Bc are spectrally distinct, and (c) B delta (the bilirubin-albumin complex) is not measured in the film. With known bilirubin mixtures, results by the assay agree with those by nuclear magnetic resonance, by a Jendrassik-Gróf method for total bilirubin, and by a liquid-chromatographic procedure. With patients' sera, the slide correlates with a liquid-chromatography-augmented Jendrassik-Gróf method, according to the following typical regression statistics (in mumol/L): for Bu, slope = 0.992, r = 0.996, intercept = -0.376, Sy X x = 5.08; for Bc, slope = 0.970, r = 0.985, intercept = -0.735, Sy X x = 8.16. The method is precise (for Bu, CV = 5.2% at an average concentration of 16.4 mumol/L, and 4.1% at 66.7 mumol/L; for Bc, CV = 6.5% at 23.4 mumol/L, and 3.8% at 151.7 mumol/L for pools of patients' sera), is relatively interference free, and has potential for extension to further applications.
Development of a stable reference material for prostatic acid phosphatase.
Authors: Duncan P H , Van Etten R L , MacNeil M L , Shaw L M 
Published: January 2020

Abstract
We describe the development of a stable reference material for prostatic acid phosphatase, derived from human prostatic tissue and human seminal fluid. The enzyme was purified by an L-tartramic acid affinity-chromatography technique. Two-dimensional electrophoresis revealed essentially no contaminating proteins, and specific tests revealed no contaminating enzymes. The preparations, in a matrix containing 30 g of human serum albumin and 0.1 mol of sodium acetate per liter, pH 6.0, were studied with respect to stability of both catalytic activity and immunological identity. We conclude that the preparations from either source are satisfactorily stable, and that either is acceptable for use in preparing clinical reference materials. These materials will be used in developing a reference method.
Factors affecting measurement of urinary oxalate.
Authors: Mazzachi B C , Teubner J K , Ryall R L 
Published: January 2020

Abstract
Using a gas-chromatographic method, we examined the effects of phosphate concentration, added calcium chloride, and pH on precipitation of oxalate from urine. All three factors are important, but the pH of precipitation is particularly so, especially in the presence of even normal concentrations of ascorbic acid. At pH 8, increases in measured oxalate ranged from 20% at an ascorbic acid concentration of 1 mmol/L to more than 300% at 15 mmol/L. Ascorbic acid is rapidly converted to oxalate at alkaline pH. We also investigated the stability of both untreated and acidified urine containing ascorbic acid during storage for up to one month at -70, -20, and 4 degrees C, and room temperature. After one month, untreated collections were stable at -70 degrees C and acidified collections at -20 and -70 degrees C. We recommend conditions for assay and storage of urine specimens that are to be assayed for oxalate under which positive interference by ascorbic acid is minimized.
Improved determination of cytochrome b5 in human erythrocytes.
Authors: Kaftory A , Hegesh E 
Published: January 2020

Abstract
A sensitive, precise enzymic/spectrophotometric method for determining cytochrome b5 in small amounts of blood is described. Mean values for healthy individuals, ages 20 to 70 years, were 0.26 (SD 0.03) mumol per liter of erythrocytes or 0.87 (SD 0.14) nmol per gram of hemoglobin. We believe the assay is preferable to methods described hitherto, primarily because of its high sensitivity.