bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nature of Materials in Serum That Interfere in the Glucose Oxidase—Peroxidase—o-Dianisidine Method for Glucose, and Their Mode of Action
Authors: Blaedel Walter J , Uhl James M 
Published: January 2020

Abstract
Separation of blood serum on Sephadex G-100 reveals three fractions that interfere with the glucose oxidase— peroxidase method for serum glucose when o-dianisidine is used as the chromogen. A low-molecular-weight fraction containing primarily uric acid, a fraction containing protein with a molecular weight of about 40 000, and a fraction of even higher molecular weight (∼ 500 000) each interfered with glucose recovery when glucose was measured by this procedure. The uric acid fraction and the isolated 40 000 molecular weight fraction interfere by competing with o-dianisidine for hydrogen peroxide in the peroxidase-catalyzed color-formation step. The high-molecular-weight fraction not only interferes with the peroxidase reaction, but also with the glucose oxidase reaction itself. These agents cause values to be low by as much as 20% in the manual determination of glucose in normal serum if their interference is not recognized.
Gas-Chromatographic Determination of Theophylline in Human Serum and Saliva
Authors: Johnson George F , Dechtiaruk Walter A , Solomon Harvey M 
Published: January 2020

Abstract
We report a gas-chromatographic procedure for routine determination of the bronchodilator, theophylline (1,3-dimethylxanthine), in serum and saliva. Volatile butyl derivatives for gas chromatography were prepared by the method of Greeley [Clln. Chem. 20, 192 (1974)], with butyliodide as the alkylating agent. Substances that interfere in the classical determination of theophylline, such as theobromine (3,7-dimethylxanthine) and phenobarbital, are well separated from theophylline by the gas-chromatographic procedure and can be quantitated if desired. It is possible to determine 1 µg of theophylline in 1 ml of serum or saliva. Between-run precision for 15 µg/ml samples was 5.3%. This determination is useful in assessing patient compliance with medication instructions and in adjusting dosage schedules of theophylline in patients attending a pediatric allergy clinic.
Solid-Phase Radioimmunoassay on Polystyrene Beads and Its Application to Dopamine-β-Hydroxylase
Authors: Rush Robert A , Kindler Shmuel H , Udenfriend Sidney 
Published: January 2020

Abstract
Antibody-coated polystyrene beads have been used to develop a solid-phase radioimmunoassay for bovine dopamine-β-hydroxylase (EC 1.14.17.1). The technique is simple and offers many advantages over other radioimmunoassay techniques, including solid-phase procedures, a major one being its adaptability to a wide range of antigen concentrations. Precision, sensitivity, and reproducibility compare favorably with those of existing methods. The ease and speed with which this test is performed have made it especially useful for clinical evaluations of serum dopamine-β-hydroxylase. Antibody-coated beads should be applicable for the assay of other antigens.
Radioimmunoassay of Digoxin—Interference by Digitoxin
Authors: Kuno-Sakai Harumi , Sakai Hideto , Ritzmann Stephan E 
Published: January 2020

Abstract
Digitoxin interference with radioimmunoassay of digoxin may present a problem in determining digoxin concentrations in the serum of patients treated with digitoxin less than four weeks before digoxin was administered. Digoxin and digitoxin values were determined in the sera of 54 patients who were receiving only digitoxin. Additionally, digoxin was added to aliquots of sera from a patient receiving digitoxin, and digoxin concentrations were determined by radioimmunoassay. Digitoxin interfered with radioimmunoassay of digoxin in that 9% of the digitoxin present was counted as digoxin. The resulting spuriously high value for measured digoxin in patients receiving digoxin, but treated with digitoxin previously, can be corrected by applying the following equation (units: µg/liter): Digoxin (corrected) = digoxin (measured) — [0.09 x digitoxin (measured)]. This correction, which may differ somewhat with batch of antiserum, is applicable for digitoxin concentrations up to about 50 ng/ml. Digoxin does not interfere with the digitoxin assay.
Inborn Errors of Metabolism— A Challenge to the Clinical Chemist
Authors: Eldjarn Lorentz , Jellum Egil , Stokke O 
Published: January 2020

Abstract
No country has as yet established satisfactory plans for combating inborn errors of metabolism. The problem is great and very complex. Some 150-200 inborn errors of metabolism are known at present, but it is likely that the types so far described only represent a fraction of those actually occurring. Until now the field of inborn errors has been dominated by pediatricians, geneticists, and biochemists. Based on his knowledge both in medicine and in biochemistry, the clinical chemist should also play an important role, and consider the diagnostic aspects of this field to be part of his responsibility. In addition, he should also take part in the further work that often is necessary to elucidate these "biochemical" disorders. The bridging of benchside and bedside medicine should be looked upon as one of the main tasks of clinical chemistry, and in the field of inborn errors such a bridging will be of great importance.
Zinc Protoporphyrin (ZPP): A Simple, Sensitive, Fluorometric Screening Test for Lead Poisioning
Authors: Lamola Angelo A , Joselow orris , Yamane T 
Published: January 2020

Abstract
The predominant fluorescent porphyrin that appears in erythrocytes as a result of chronic lead absorption or iron deficiency anemia is zinc protoporphyrin. This compound can be fluorometrically assayed in diluted whole blood with high sensitivity. An extremely simple and rapid test for lead absorption is described that is based on this assay. Results of a field trial indicate that this test should be seriously considered as a primary screening test for monitoring the effects of chronic lead absorption.
Organic Nitrogen-Selective Detector Used in GasChromatographic Determination of Some Anticonvulsant and Barbiturate Drugs in Plasma and Tissues
Authors: Toseland Patrick A , Albani Michael , Gauchel Franz D 
Published: January 2020

Abstract
The specific nitrogen flame-ionization detector was used for the rapid simultaneous determination of eight anticonvulsant drugs and one drug metabolite in plasma and for three of the drugs in tissues. The system of analysis allows the occasional rapid estimation of barbiturate in plasma. No derivative formation is required and the whole range of drugs can be determined in a single diethyl ether extract of plasma in about 20 min.
Quality Assurance in Health Care: Missions, Goals, Activities
Authors: Eilers Russell J 
Published: January 2020

Abstract
The most challenging mission of medical personnel today is quality assurance in health care. To meet this challenge, the essential elements of a six-phase system for total quality control for the medical laboratory are outlined under the headings of design control, incoming material control, process control, output control, reliability control, and special verification studies. Review of existing goals and activities of programs related to this mission indicates both problems and rich opportunities for individual laboratory professionals and their organizations. For effective implementation of this mission, the laboratory professionals will have to create the atmosphere of a collegium where all interested scientists communicate across disciplines to eliminate the systematic biases and improve the accuracy, precision, and specificity of clinical laboratory measuring systems, to assure medically meaningful and useful assay results for the broad spectrum of health care that is necessary for the well, the near-well, and the sick.
Kinetic Determination of Glucose with the GEMSAEC (ENI) Centrifugal Analyzer by the Glucose Dehydrogenase Reaction, and Comparison with Two Commonly Used Procedures
Authors: Lutz Rudolf A , Flückiger Jürg 
Published: January 2020

Abstract
A new glucose dehydrogenase preparation has been used to determine the glucose concentration in serum or plasma with the GEMSAEC(ENI) analyzer. The reaction is sufficiently linear to be suitable for a kinetic determination. A sample volume of 15 µl or less is needed, and 14 determinations can be done simultaneously within 160 s (the time needed for loading the samples and reagents into the distribution disc plus a reaction time of 70 s). The reaction is linear up to 300 mg of glucose per 100 ml, but with special computer software linearity could be extended to 1 g of glucose per 100 ml. Day-to-day and within-day precision have been tested with a number of different sera and standards. Accuracy has been checked by comparing the results with those obtained by the hexokinase and the glucose oxidase/peroxidase methods. A better agreement was found with the hexokinase method. The proposed procedure has the advantage of involving only one enzymatic step and of directly measuring reduced coenzyme formation at 340 nm.
Thyroid-Function Tests in Diphenylhydantoin-Treated Patients
Authors: Stjernholm Melvin R , Alsever Robert N , Rudolph Merritt C 
Published: January 2020

Abstract
We compared the free-thyroxine index in normal adults and in euthyroid patients taking diphenylhydantoin. All subjects had normal serum thyrotropin concentrations. Serum thyroxine concentrations were determined by two commonly used competitive protein-binding assays, which yielded slightly different values, but which consistently showed the same degree of decrease in mean serum thyroxine concentration in drug-treated patients as compared to the normal subjects. When 14C-labeled diphenylhydantoin was added to serum before the assay, it was separated from thyroxine in the Ames method, whereas by the Murphy-Pattee method both drug and thyroxine were extracted together. Thus, the decrease in serum thyroxine concentrations during diphenylhydantoin therapy cannot be the result of drug interference with the binding of thyroxine to binding proteins in the assays. Triiodothyronine uptake, evaluated by two methods, was identical in the two groups. The free-thyroxine indexes for all normal persons were within the manufacturer's normal range, but 21% of the drug-treated patients had subnormal indexes by the Ames method; the indexes as measured by the Murphy— Pattee method were in the lower half of the normal range. Because the triiodothyronine uptake was unaffected by the drug treatment, the decreases in the indexes must have resulted from the lower serum thyroxine concentrations. We conclude that the free-thyroxine index may not provide a valid estimate of either the clinical status or the free-thyroxine concentration in patients taking diphenylhydantoin.
Kinetic Enzymatic Method for Determining Serum Creatinine
Authors: Moss Gerald A , Bondar Richard J L , Buzzelli Diane M 
Published: January 2020

Abstract
Creatinine amidohydrolase is used to measure serum creatinine in a totally enzymatic procedure. Creatine, produced by hydrolysis, is acted upon by creatine kinase, and then by pyruvate kinase and lactate dehydrogenase, to result in a change in absorbance at 340 nm. The amount of creatinine present is related to the rate of change in A340 and is determined from a standard curve. Absorbance and concentration are linearly related to 100 mg/liter and only 250 µl of serum is required. At 1.0 g/liter, heparin, oxalate, citrate, ethylenediaminetetraacetate, ascorbate, or glucose had no significant effect on the accurate determination of creatinine; higher concentrations (30 g/liter) had inhibitory effects on the test. Analytical recovery of creatinine added to either normal or abnormal sera averaged 102%. When results of this procedure and of the standard direct Jaffé test were compared, the latter were significantly higher. Unlike the Jaffé method, the present method of determining creatinine is rapid (about 10 min per test), subject to few or no interfering substances, and requires no serum deproteinization.
Quantitative Method for Estimating Fecal Amino Acids
Authors: Owens Christopher W I , Padovan Walfredo 
Published: January 2020

Abstract
We describe a method for quantitatively estimating 24 ninhydrin-reacting substances, including the commoner amino acids, in fecal dialysate prepared from ingested dialysis bags retrieved from fresh stool. It is accurate to 2 µmol of α-amino nitrogen per liter of fecal dialysate, and for most substances recovery of added standards is 100%. It involves dilution, ultrafiltration, and automated ion-exchange column chromatography of the dialysate. Some normal values are provided.
Iodination of Morphine and Dihydromorphine, as Related to Radioimmunoassay
Authors: Davis Raymond , Feldhaus Joanne , Heveran John , Wicks Richard , Peckham Maria 
Published: January 2020

Abstract
Direct iodination of morphine or dihydromorphine with iodine-125 results in products that bind to antibody raised by immunization of animals with a 3-O-carboxymethylmorphine/bovine serum albumin immunogen. Iodination of morphine or dihydromorphine with iodine-127 under identical conditions failed to yield these immunologically active products, suggesting that the results obtained with iodine-125 are in part due to a radiolytic reaction not observed with the iodine-127.
Clinical Determination of Methemalbumin
Authors: Andres Scott F , Kregoski Thomas J , Frey Charles F , Joseph Ramon R , McCann Daisy S 
Published: January 2020

Abstract
We developed an assay for methemalbumin in biological fluids by using diethylaminoethyl-Sephadex ion-exchange chromatography to separate this protein from interfering components, including hemopexin, transferrin, hemoglobin, and haptoglobin/hemoglobin complex. Initial screening of the samples requires measurement of A280/A405 ratios of the peak tubes of the isolated albumin fraction. Values exceeding 30 indicate that methemalbumin is absent, and no further work is required. Values of less than 30 suggest that methemalbumin is present in the original sample, whereupon the presence and amount of methemalbumin can be ascertained by colorimetric assay for iron with use of ferrozine. Results may be expressed either in terms of micrograms of methemalbumin iron per gram of albumin or in milligrams of methemalbumin per liter. The reproducibility of the method is of the order of ±7% (SD). Normal persons have essentially no methemalbumin iron in their serum. Three individuals with hemorrhagic pancreatitis showed values of 65, 98, and 198 µg of methemalbumin Fe per gram of albumin.
Fluorometric Enzymatic Determination of Total Cholesterol in Serum
Authors: Huang Hua-shan , Kuan Jui-chang W , Guilbault George G 
Published: January 2020

Abstract
We describe a fluorometric enzymatic method for determining total serum cholesterol, based on hydrolysis of cholesterol esters to free cholesterol by cholesterol ester hydrolase (EC 3.1.1.13). The free cholesterol formed, as well as that initially present, is then oxidized by cholesterol oxidase (EC 1.1.3.6) to cholest-4-en-3-one with simultaneous production of hydrogen peroxide. The latter catalytically oxidizes homovanillic acid in the presence of peroxidase (EC 1.11.1.7) to form the highly fluorescent 2,2'-dihydroxy-3,3'-dimethoxy-biphenyl-5,5'-diacetic acid. A calibration curve is constructed from data on a series of standard cholesterol solutions vs. the corresponding fluorescence change (Δf/5 min). This curve is linear up to 4.0 g of total serum cholesterol per liter of serum. The method is specific, precise, accurate, rapid, and simple, and results correlate well with those obtained by both the Liebermann-Burchard procedure and the colorimetric enzymatic method (correlation coefficients, 0.984 and 0.981, respectively)
Improved Method for Enzymatic Determination of Serum Triglycerides
Authors: Ziegenhorn Joachim 
Published: January 2020

Abstract
I describe an enzymatic method for determining serum triglycerides (triacylglycerols). The triglycerides are hydrolyzed by a mixture of lipase and esterase. The glycerol released is determined by kinetic fixed-time analysis, with use of glycerol kinase, pyruvate kinase, and lactate dehydrogenase. Through addition of the competitive inhibitor ATP the Michaelis constant of pyruvate kinase is apparently increased, considerably extending the linearity of the assay. There is no need for serum blanks or reagent blanks. The method has been adapted to a centrifugal analyzer (the ENI GEMSAEC). It yields satisfactory results with regard to precision, accuracy, and insensitivity to interferences
Device for More Economical Standby Operation of Continuous-Flow Analyzers
Authors: Wardlaw Stephen C 
Published: January 2020

Abstract
To decrease the reagent-consumption rate of continuous-flow analyzers, I constructed a device that allows standby operation. The device, when actuated by switching off the sampler, decreases the effective pumping rate to less than 1/15 normal. The bubble pattern remains virtually undisturbed, and the system can be immediately restarted for emergency use. During five months of use in our laboratory with a Technicon platelet counter, the device has decreased reagent consumption by 60%, while allowing 24-hour-a-day operation. There have been no analytical errors traceable to the device, and no mechanical problems have arisen. I describe the use of the device in a continuous-flow system for determination of creatinine
More Sensitive Automated Detection of Polyamines in Physiological Fluids and Tissue Extracts with o-Phthalaldehyde
Authors: Marton Laurence J , Lee Patrick L Y 
Published: January 2020

Abstract
o-Phthalaldehyde reacts with primary amines to form an intensely blue-fluorescing product. Replacing ninhydrin with this compound in our automated high-pressure liquid-chromatographic technique for determination of polyamines, we achieved a 6-to 10-fold increase in sensitivity. Linearity and reproducibility are excellent, and the method is shown to be applicable to analysis of physiological fluids and of tissue extracts.
Continuous Determination of the Oxygen Dissociation Curve for Whole Blood
Authors: Rossi-Bernardi Luigi , Luzzana Massimo , Samaja Michele , Davi Mario , DaRiva-Ricci Daniela , Minoli Jolanda , Seaton Brian , Berger Robert L 
Published: January 2020

Abstract
We report here the development of a new method that allows continuous determination of the oxygen dissociation curve for microsamples (600 µl) of whole blood under conditions of pH, pco2, methemoglobin concentration, and 2,3-diphosphoglycerate content closely approaching those found in the circulatory system. The method consists of gradually oxygenating a blood sample by adding H2O2 in the presence of catalase (EC 1.11.1.6), to produce the reaction H2O2 → H2O + ½ O2. Because the total oxygen content of blood can be derived from the known rate of H2O2 addition and the po2 is determined in the liquid phase by an oxygen electrode, the two functions (total O2 content) and (% oxygen saturation) vs. po2 are simple to calculate. pco2 and pH are controlled by adding base simultaneously with the gradual oxygenation of blood. The method described thus avoids the direct measurement of oxygen saturation of whole blood.
Enhancing Effect of Surfactant and Protein on Hydrolysis of Thymolphthalein Monophosphate by Purified Prostatic Acid Phosphatase
Authors: Foti Andras G , Herschman Harvey , Cooper J Fenimore , imFeld Hedi 
Published: January 2020

Abstract
Purified prostatic acid phosphatase catalyzes the hydrolysis of thymolphthalein monophosphate 10-fold faster if an optimal concentration of Brij 35 (a wetting agent) or protein (bovine serum albumin or human serum proteins) is present. Results of gel filtration, dialysis, and sucrose density-gradient centrifugation analysis suggest that the substrate must combine with detergent or protein before the enzyme can catalyze its hydrolysis.
Enzymatic Immunoassay vs. Gas/Liquid Chromatography for Determination of Phenobarbital and Diphenylhydantoin in Serum
Authors: Booker Harold E , Darcey Barbara A 
Published: January 2020

Abstract
The antiepileptic drugs diphenylhydantoin and phenobarbital were measured in serum by a new commercially available enzyme immunoassay procedure ("EMIT," Syva Corp.). The procedure requires &lt;5 min and no more than 50 µl of serum per determination. It is simple; only four steps (pipetting and diluting with an automatic pipettor-dilutor) are required before spectrophotometry. Twenty replicate analyses of a serum containing phenobarbital and diphenylhydantoin gave results with a CV of 6.8% and 9.1%, respectively. Results attained in a large series of patients were compared with results by a gas/liquid chromatographic procedure. For phenobarbital r = 0.97, and for diphenylhydantoin r = 0.98. No false negatives or false positives were encountered.
Screening for Albuminuria: A Case for Estimation of Albumin in Urine
Authors: BenGershôm E 
Published: January 2020

Abstract
The usefulness of bromcresol green for estimating albumin in urine was evaluated by comparison with the Laurell "rocket" technique. In contrast to the bromcresol green method applied for urinary albumin, rather doubtful results were obtained with conventional (Microzone) electrophoresis for albumin and with precipitation techniques for total protein estimation. Albumin estimation with bromcresol green is recommended as a more reliable substitute for total-protein estimations in urine. Limitations of bromcresol green are also pointed out.
Pollution Control and Suggested Disposal Guidelines for Clinical Chemistry Laboratories
Authors: Pragay Desider A 
Published: January 2020

Abstract
Pollutants generated by clinical chemistry laboratories of two cities (Buffalo, N. Y. and Rochester, N. Y.) are described. A stepwise procedure is suggested on how to deal with the toxic liquid wastes from such laboratories. A brief guideline of chemical procedures for the decontamination of selected toxic elements and compounds is included.
Diagnosis of Type III Hyperlipoproteinemia by Chromatography of Plasma Lipoproteins on Columns Containing Agarose
Authors: Shepherd James , Packard Christopher J , Dryburgh Frances J , Third Jane L H C 
Published: January 2020

Abstract
Agarose column chromatography has been used to separate plasma lipoproteins into very-low-density lipoproteins (VLDL), low-density lipoproteins (LDL) and high-density lipoproteins (HDL). Applied to the diagnosis of primary type III hyperlipoproteinemia, the procedure is capable of demonstrating three characteristic and specific changes from normality in the elution pattern of lipoproteins from patients with this condition. In the type III profile there is (a) incomplete separation of VLDL from putative LDL material, (b) early elution of the type III LDL with respect to a normal LDL marker, and (c) relative deficiency of type III LDL with elution characteristics of normal LDL. We advocate the use of this method in the diagnosis of type III hyperlipoproteinemia.