bluuebunny/crossref_metadata_2025_split huggingface dataset:
Creatine kinase in serum: 5. Effect of thiols on isoenzyme activity during storage at various temperatures.
Authors: Szasz G , Gerhardt W , Gruber W 
Published: January 2020

Abstract
We studied changes in the activity of human creatine kinase isoenzymes (native MM in serum, MM, MB, and BB preparations in serum matrix) on storage in the presence of 0, 10, 20, and 50 mmol of N-acetyl cysteine, 2-mercaptoethanol, and 1-thioglycerol per liter of serum at 37, 30, 25, 4, and -20 degrees C. We also assessed the stability of the thiols under the same conditions. We generally confirmed increasing stability in the sequence: BB, MB, and MM isoenzyme. Above 30 degrees C irreversible inactivation is very rapid, even in the presence of thiols. At lower temperatures endogenous MM is sufficiently stable; thus, the use of protective thiols can be restricted to sera expected to contain isoenzymes MB or BB. Our studies lead us to prefer use of 50 mmol of N-acetyl cysteine per liter of serum. The other thiols cause turbidity to develop earlier and their decomposittion products diminish the activity more. The initial activity of the MB and BB preparations increased by as much as 2.3- and 1.8-fold on storage with thiols. This effect was not observed with either endogenous MB and MM or with the MM prepartion.
Emergency procedure for digoxin radioassay.
Authors: Chen I W , Sperling M , Volle C , Maxon H R 
Published: January 2020

Abstract
A rapid but precise radioassay for digoxin has been developed by optimizing the conditions for antigen-antibody interaction and for separation of bound and free fractions. This new procedure involves incubation of radioactively labeled antigen, antibody, and standard or sample at 3 degrees C for 10 min. Charcoal is then added, the mixture centrifuged for 5 min, and the radioactivity of the supernate counted. Results are available in less than 1 h after receipt of the specimens, making the procedure suitable for emergency determinations. Results correlate well with those by our routine procedure (Becton Dickinson) (r = 0.9739, y = 0.0356 + 0.9915x, n = 49). Analytical recovery of added pure digoxin exceeds 94%, both within and between assay CV's are less than 8%.
Improved thin-layer chromatographic method in the diagnosis of mannosidosis.
Authors: Friedman R B , Williams M A , Moser H W , Kolodny E H 
Published: January 2020

Abstract
An improved thin-layer chromatographic method is described for the facile separation of neutral oligosaccharides excreted in the urine of patients with mannosidosis. The urine sample is treated with mixed-bed ion-exchange resin to remove charged species. The eluate is then chromatographed on silica gel thin-layer plates with n-propanol water as the developer. Eleven unique orcinol-positive components can thus be resolved. The advantages of this method over previously described techniques are the ease and rapidity of assay, better resolution of components, and clarity of resolution. It should be applicable to other disease states in which distinctive neutral carbohydrate products are produced.
Double-antibody enzyme immunoassay for nortriptyline.
Authors: Al-Bassam M N , O'Sullivan M J , Gnemmi E , Bridges J W , Marks V 
Published: January 2020

Abstract
beta-D-Galactosidase (EC 3.2.1.23) from Escherichia coli was conjugated to desmethylnortriptyline by means of a bifunctional cross-linking reagent, dimethyl adipimidate, and used in a double-antibody immunoassay for nortriptyline. Eighty percent of the enzyme activity was retained after conjugation; 75% of the enzyme was conjugated to desmethylnortriptyline. In the final immunoassay the enzyme activity of the bound fraction was determined with o-nitrophenyl-beta-D-galactopyranoside as substrate. The sensitivity, precision, and simplicity of the enzyme immunoassay compared favorable with that of a published radioimmunoassay method. Results for nortriptyline in plasma samples correlated well with those determined by either radioimmunoassay or gas-chromatography.
An impurity in the buffer 2-amino-2-methyl-1-propanol, which correlates with depression of measured alkaline phosphatase activity.
Authors: Williamson J A , Thompson J C 
Published: January 2020

Abstract
Recent findings indicate that the buffer 2-amino-2-methyl-1-propanol, widely used in clinical measurement of alkaline phosphatase activity, contains an impurity that inhibits the activity of the enzyme. Analysis of several lots of 2-amino-2-methyl-1-propanol has demonstrated the presence of a material, the concentration of which correlates well with alkaline phosphatase activity. Mass spectral analysis of this material indicates that it is a substituted ethylenediamine compound. Zinc chelation is discussed as a possible mode of its inhibition. Further work is in progress to separate and characterize this and other compounds in the buffer and to determine their modes and degrees of alkaline phosphatase inhibition.
Triiodothyronine uptake test in which antibody-coated tubes are used compared to two other tests in which precipitation separations are used.
Authors: Szpunar W E , Block M 
Published: January 2020

Abstract
A triiodothyronine uptake test in which antibody-coated tubes are used (Clinical Assays) was compared to two other such tests in which silicate tablets (Nuclear-Medical Laboratories, Inc.) or macroaggregated albumin (Diagnostic Corporation of America) are used to separate the bound from the free fraction. The Clinical Assays test showed good linear correlation with the values obtained by the other two tests on 67 samples. The interassay coefficient of variation was 4.8%. The correlation between the values obtained and the clinical evaluation on 60 patients also was essentially the same as for the other two tests, 80%.
Quality control of measurements of pH, carbon dioxide tension, and total carbon dioxide in plasma.
Authors: Savory D J , Pryce J D 
Published: January 2020

Abstract
We have measured total carbon dioxide in plasma with a new carbon dioxide analyzer, and compared the results with total carbon dioxide data derived from measurements of carbon dioxide tension and pH. The results agree sufficiently well to demonstrate that the new instrument provides a simple, efficient procedure for monitoring the precision and accuracy of pH, carbon dioxide tension, or total carbon dioxide in plasma.
Kinetic measurement of alpha-amylase with a centrifugal analyzer.
Authors: Iosefsohn M , Hicks J M 
Published: January 2020

Abstract
We compared results of an enzymic assay for alpha-amylase (EC 3.2 1.1), adapted to a centrifugal analyzer (GEMSAEC), with results by the manual dyed-starch (Phadebas) amylase assay. We assessed linearity and precision, and the stability of the reagent. The kinetic procedure is rapid, precise, requires only 25 microliter of serum, and thus is evidently suited for both pediatric and emergency use.
Enzymic assay for lecithin in amniotic fluid.
Authors: Anaokar S , Garry P J , Standefer J C 
Published: January 2020

Abstract
We describe an enzymic method for determining lecithin in amniotic fluid. Phospholipase D from savoy cabbage is used to liberate choline from lecithin, and the liberated choline is oxidized to betaine and hydrogen peroxide by choline oxidase from Arthrobacter globiformis. The hydrogen peroxide forms a colored complex with phenol and 4-aminoantipyrene in the presence of horseradish peroxidase, and this color is measured spectrophotometrically. The method is relatively easy, precise, and accurate, requires less time and sample than other methods, and offers a reliable alternative to the lecithin/sphingomyelin ratio techniques for assessing fetal lung maturity.
Radioimmunoassay for pantothenic acid in blood and other tissues.
Authors: Wyse B W , Wittwer C , Hansen R G 
Published: January 2020

Abstract
We describe a radioimmunoassay for pantothenic acid in biological tissues. D-Pantothenic acid was conjugated with bovine serum albumin by use of a bromoacetyl derivative of pantothenic acid, and antibody to this antigen was raised by injecting it into the foot pads of rabbits. For the radioimmunoassay, a 100-fold dilution of the resulting antiserum was incubated with radiolabeled pantothentic acid. The antibodies were precipitated and dissolved, and the radioactivity of the solution was measured in a liquid scintillation counter. Between 5 and 125 ng of pantothenic acid can be detected in 75 muL of tissue extract. Validation included recovery and precision studies, parallelism with tissue extracts, and competitive binding studies. Results of the radioimmunoassay and those of microbiological assay with use of Lactobacillus plantarum correlated well (r = 0.80).
Cell-surface receptors in health and disease.
Authors: Blecher M 
Published: January 2020

Abstract
Assessment of interaction of hormones and neurotransmitters with their cell-surface receptors can lead to an understanding of the molecular mechanisms that underlie diseases in man involving resistance and supersensitivity to these humoral agents and to pharmacological agents. They can also lead to the development of simple diagnostic procedures for such disorders, as well as the development of radioreceptor assays for humoral agents and drugs in blood and tissues, assays which combine sensitivity comparable to those involving radiommunoassay with a greater biological accuracy.
Absorbance measurement in cuvettes lying longitudinal to the light beam.
Authors: Eisenwiener H G , Keller M 
Published: January 2020

Abstract
Measurement in cuvettes with their longitudinal dimension parallel to the light beam, while under the influence of a centrifugal force, has many advantages that are not immediately apparent. This survey summarizes the advantages in comparison to cuvettes standing with their long axis perpendicular to the light beam: in the latter the pathlength is fixed by the geometry, but if the cuvette is lying longitudinal to the light beam the pathlength is given by the filling volume. Because of the dependence of the pathlength on the filling (reaction) volume when cuvettes are lying longitudinal to the light beam, the calculation formulas show that the calculation factors, both for enzyme and substrate determination, become independent of the reagent volume form. This is demonstrated by simple equations and confirmed in practice by use of the (Cobas) Bio centrifugal analyzer in assays for glucose and aspartate aminotransferase.
Comparison of three iodination methods for human somatotropin.
Authors: Apinyacharti P , Baxter R C 
Published: January 2020

Abstract
Human somatotropin (growth hormone) iodinated by use of lactoperoxidase or Chloramine T added stoichiometrically has been compared with hormone iodinated by conventional Chloramine T method. The three preparations were indistinguishable, both in their stability to storage and in their suitability for use in radioimmunoassay. Degradation of tracer, as measured by decreasing precipitability with trichloroacetic acid, was found to be an unsatisfactory measure of immunoreactivity, because aggregates of high relative molecular mass formed during storage at--15 or--80 degrees C are less immunoreactive.
Improved method of purifying some radiolabeled glycopeptide hormones.
Authors: Patritti-Laborde N , Yoshimoto Y , Wolfsen A , Odell W D 
Published: January 2020

Abstract
We describe a simplified method for purifying radiolabeled glycopeptide hormones (thyrotropin, lutropin, follitropin, and human choriogonadotropin), which results in preparations of over 95% immunoreactivity. This method is based on competitive elution from columns of the plant lectin, concanavalin A, and is applicable to glycopeptide hormones derived from several species.
Double light-chain disease: a case report.
Authors: Dalal F R , Winsten S 
Published: January 2020

Abstract
A patient with massive proteinuria was discovered to have double light-chain disease. Immunological studies demonstrated monoclonal light chains of both the lambda and kappa type in urine. The light chains were separate and distinct and were not found to be a part of any of the whole molecule immunoglobulins such as IgG, IgM, IgA, IgD, or IgE. Uniqueness of the proteins was confirmed by column chromatography. Clinical studies showed that the patient had multiple myeloma.
Stability of dried blood spots on paper, as used in screening neonates for hypothyroidism.
Authors: Davis G , Poholek R 
Published: January 2020

Abstract
Thyroxine values for dried blood spots on paper may be low if the paper has been long exposed to high ambient temperature and (or) humidity and (or) to sunlight. Low values are associated with poor extractability of the red color from the spots. We recommend appropriate precautions for such samples.
Evaluation of a commercial enzyme immunoassay for insulin in human serum, and its clinical application.
Authors: Yoshioka M , Taniguchi H , Kawaguchi A , Kobayashi T , Murakami K , Seki M , Tsutou A , Tamagawa M , Minoda H , Baba S 
Published: January 2020

Abstract
We applied a "sandwich" method, with use of beads coated with anti-insulin serum and of peroxidase-labeled anti-insulin serum, to an enzyme immunoassay of insulin in human serum. 5-Aminosalicylic acid was used as the substrate for the enzymic reaction. As little as 5 milli-int. units of insulin per liter of serum insulin was detectable. Reproducibility was satisfactory, but extraordinarily high concentrations of proinsulin and of hydrogen donors such as reduced glutathione affect results of the assay. Values determined by our enzyme immunoassay and by double-antibody radioimmunoassay correlated highly (r = 0.938, p less than 0.001, n = 216). We recommend this method for use in the clinical laboratory.
On-line continuous potentiometric measurement of potassium concentration in whole blood during open-heart surgery.
Authors: Osswald H F , Asper R , Dimai W , Simon W 
Published: January 2020

Abstract
We describe a flow-through system with an ion-selective electrode for measurement of blood potassium ion concentration, continuously and on-line off the extracorporeal blood circulation in an operating theater during human open-heart surgery. Comparison measurements were made with the SMA flame photometer (blood plasma) and an Orion SS 30 sodium/potassium analyzer (whole blood). The potassium concentration values obtained with the flow-through system agree well with the ones determined with the flame photometer. The time delay of the measurement with the flow-through system was relatively long (2 min) but delays of only 10--20 s seem feasible. Short time delays can deepen insight and simplify rational treatment under surgery conditions.
Spironolactone-associated digoxin radioimmunoassay interference.
Authors: Silber B , Sheiner L B , Powers J L , Winter M E , Sadée W 
Published: January 2020

Abstract
Apparent digoxin was measured in the serum of 21 patients receiving spironolactone and in 21 controls, by use of a sequential-saturation 3H-radioimmunoassay (RIA) and an equilibrium 125I-RIA. No patient had been given digoxin for at least four weeks. "Digoxin" values in the former group were significantly (p less than 0.05) higher than in the control group, and often were in or near the "therapeutic" range by the equilibrium 125I-RIA, but not by the sequential-saturation 3H-RIA. Canrenone (a major active metabolite of spironolactone) in the serum of the former group was measured by a newly developed liquid-chromatographic technique and correlated (r = 0.73) with "digoxin" concentrations by the 125I-RIA. However, external addition of canrenone to control serum in comparable concentrations did not cause appreciable "digoxin" values by the 125I-RIA. These findings suggest that other metabolites of spironolactone are responsible for the assay interference, the degree of which appears to depend on antibody specificity. Therefore, assay specificity should be established in clinical laboratories by using digoxin-free serum from patients ingesting spironolactone, and not by using spironolactone- or canrenone-fortified digoxin-free serum.
Blood cyanide and thiocyanate concentrations after administration of sodium nitroprusside as hypotensive agent in neurosurgery.
Authors: Bogusz M , Moroz J , Karski J , Gierz J , Regieli A , Witkowska R , Gołabek  
Published: January 2020

Abstract
In a group of 50 neurosurgical patients receiving sodium nitroprusside as a hypotensive agent, in doses of 50--2131 microgram/kg body weight, whole blood cyanide was estimated before infusion of drug, during infusion, immediately after infusion, and 1 and 3 h later. Cyanide values increased significantly, reaching the maximum in a sample taken immediately after infusion (mean value, 333; highest value, 1800 microgram/liter). Values correlated closely with both dose and rate of infusion. Blood thiocyanate, estimated before, immediately after, and 3 h after the infusion, showed no significant changes in thiocyanate concentration. In any case, no signs or symptoms of cyanide or thiocyanate poisoning were observed. We conclude that sodium nitroprusside, in the proper dose and given at the proper rate, does not precipitate cyanide poisoning.
Comparison of liquid- and gas-liquid chromatographic assays of 5-fluorouracil in plasma.
Authors: Christophidis N , Mihaly G , Vajda F , Louis W 
Published: January 2020

Abstract
A liquid-chromatographic assay of 5-fluorouracil in plasma is described. Advantages of this procedure over gas chromatography are the simpler extraction procedure, elimination of the need for a derivitization step with silylating agents, and a 20-fold greater sensitivity. The minimum detectable concentration of 5-fluorouracil in plasma is 25 microgram/L. The enhanced sensitivity enabled measurement of the concentrations of 5-fluorouracil found in plasms of patients receiving continuous intravenous infusions of the drug; such concentrations are generally unmeasurable by gas-chromatographic methods. We compared liquid-chromatographic and gas-chromatographic measurements on 36 plasma samples obtained from patients after rapid intravenous injection of 5-fluorouracil. The resulting correlation coefficient was 0.97, with a regression slope of 0.94. The liquid-chromatographic method is free of interference from other cytotoxic agents, anti-emetics, and folate derivatives that are frequently combined with 5-fluorouracil therapy.
Arylesterase in serum: elaboration and clinical application of a fixed-incubation method.
Authors: Lorentz K , Flatter B , Augustin E 
Published: January 2020

Abstract
A sensitive, specific, and simple method for determining serum or urine arylesterase (EC 3.1.1.2) is described. The enzyme acts on phenyl acetate to release phenol, which produces a stable indophenol dye with 4-aminoantipyrine and potassium ferricyanide. Arylesterase, a thiol enzyme, is reactivated by 2-mercaptoethanol and by cysteine, but not by reduced glutathione. Calcium is indispensable to stabilize and to activate (Km = 0.85 mmol/L) the enzyme; complete protection is achieved at CaCl2 20 mmol/L. Magnesium acts as a weak (Ki = 116 mmol/L), lanthanum as a potent (Ki = 5 mumol/L) competitive inhibitor. The activity is measured in diluted sera at phenyl acetate 4.0 mmol/L (Km = 1.12 mmol/L), pH 7.8 and 25 degrees C. The normal range extends from 53 to 186 kU/L, and four isoenzymes are present in sera from healthy adults. Arylesterase decreases in hepatic disorders, especially in cirrhosis and carcinoma of the liver, with reduction of the penultimate fraction in polyacryalmide gel electrophoresis.
The use of immobilized enzyme reactors in continuous-flow analyzers for the determination of glucose, urea, and uric acid.
Authors: Chirillo R , Caenaro G , Pavan B , Pin A 
Published: January 2020

Abstract
We describe the use of immobilized enzymes in assay methods for the determination of glucose with glucose oxidase, uric acid with uricase, and urea with urease in serum samples. The enzyme reactor tubes were adapted to continuous-flow analyzers (Technicon AA II, SMA 12/60, and SMAC) used in routine laboratory determinations, and results with their use were compared to those from assays involving soluble enzymes. We substituted the reactors for the free enzyme reagents in the respective channels of the SMA 12/60 and SMAC, without modifying the parameters of the remaining channels. We compared assay sensitivity, precision, and carryover for immobilized and conventional liquid enzymes. Immobilized enzyme reactors provide accurate, reliable, convenient, and economical alternatives to the use of free enzyme reagents in these systems.
Identification of alpha1-lipoproteins in crossed immunoelectrophoresis.
Authors: Cline L J , Crowle A J 
Published: January 2020

Abstract
Evans Blue dye binds selectively, but with different avidities, to five major antigens in human serum. The anodic mobility of the antigen-dye complexes is greater than that of the antigens alone in crossed immunoelectrophoresis, which is of practical value for identification. We used this characteristic to show that in some human sera there is a population of alpha1-lipoprotein molecules that migrates electrophoretically in the beta-lipoprotein region, where in conventional zone electrophoresis it could be mistaken for beta-lipoprotein. We also demonstrate that horses, unlike rabbits, rarely make precipitins to human serum alpha1-lipoprotein. Equine antiserum to human serum therefore generally is useless for detecting this important serum antigen in immunoelectrophoresis.
Influence of posture on free calcium and related variables.
Authors: Renoe B W , McDonald J M , Ladenson J H 
Published: January 2020

Abstract
We measured free calcium and related variables before and after the subject changed from the upright to the supine posture, doing 15 separate such experiments on 11 healthy men. After such a change, free calcium (1.7 +/- 0.4%), total calcium (4.6 +/- 0.7%), total protein (11.5 +/- 1.4%), albumin (12.2 +/- 2.0%), total magnesium (3.8 +/- 0.9%), and the activity of hydrogen ion (2.9 +/- 1.0%) decreased significantly (values are means +/- SEM), but promptly reverted when three subjects assumed the alternative posture. Changes in lactate values were not rapidly reversible; sodium and potassium showed no significant change. The mechanism of the changes in free calcium is unclear, but they correlated only with the changes in total calcium and were notably less than the changes in total calcium, indicating that posture will have less effect on the interpretation of free calcium values than on values for total calcium.
Measurement of 4-hydroxyphenylacetic aciduria as a screening test for small-bowel disease.
Authors: Chalmers R A , Valman H B , Liberman M M 
Published: January 2020

Abstract
We evaluted measurement of urinary 4-hydroxyphenyl acetic acid as a potential screening method for small-bowel disease and bacterial overgrowth syndromes in 360 unselected acutely ill infants and children. Control data were obtained on 120 healthy children, ages 1.5 to 15 years, from a general medical practice, 48 healthy infants, ages one to five years, from local day nurseries, and 150 healthy babies, ages less than one to eight days. Comparative data were from 300 acutely ill hospitalized babies and children, ranging in age from less than one day to 15 years and without clinical evidence for small-bowel disease and bacterial overgrowth syndrome. No false-negative results and only 2% false-positive results were observed. Among the 10 patients whose urinary excretion of the analyte was considered to be abnormal were patients with Giardia lamblia infestation, ileal resection with blind loop, and other diseases of the small intestine associated with bacterial overgrowth. We conclude that measurement of 4-hydroxyphenylacetic acid excretion is useful in screening for such diseases.