bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Coulometric Determination of Glucose in Human Serum
Authors: Simon Robert K , Christian Gary D , Purdy William C 
Published: January 2020

Abstract
The coulometric titration method is combined with the use of an enzymatic analytic reagent for the determination of glucose in human serum. The glucose in 25 µl. of serum is determined in a protein-free filtrate (PFF) with an accuracy of ± 3% and a coefficient of variation of approximately 2%. The procedure routinely covers a concentration range of 25-250 mg/100 ml. Calibrations are linear to at least 450 mg./100 ml. with zero intercept. Glucose oxidase specifically catalyzes the aerobic oxidation of glucose to hydrogen peroxide. The peroxide reacts with iodide, in the presence of molybdenum (VI) catalyst, to form iodine. A known excess of thiosulfate reduces the iodine as it is produced. The reagents and the sample are incubated at 25.0° and pH 5.1. After 15 min., the pH is adjusted to 8.0 with phosphate reagent to stop the enzymatic reaction. The residual thiosulfate is titrated coulometrically with iodine at pH 8.0 to a dead-stop end point at a generating current of 0.4825 ma. The difference between the sample and thiosulfate reagent titers is proportional to the glucose concentration. The method is empirical. Peroxide-reducing impurities in the glucose oxidase preparation and mutarotation equilibrium prevent the complete recovery of glucose under the conditions of the experiment. Calibrations are reproducible from day to day and week to week. Reagents and the PFF constitute a negligible titration blank. Only 1 calculation is necessary. A simplified apparatus and procedure for the preparation of PFF’s permits 15 manual determinations per hour. Coulometric assays of commercial serum controls are accurate to within 3-4%. Data indicate that the precision of the coulometric method exceeds that of the Auto-Analyzer, Folin-Wu, Glucostat, and Nelson-Somogyi procedures. The proposed method is free from interferences at normal serum levels.
SYMPOSIUM ON URINARY CONSTITUENTS OF LOW MOLECULAR WEIGHT Session III
Authors: Bush Ian E 
Published: January 2020

Abstract
A summary of the strategy and progress in devising a general system of biochemical analysis based on the direct photometry, or "scanning" of thin-media chromatograms is presented. Recent results suggest that the method is as precise and as accurate as other types of quantitative chromatography. It is capable of reasonably easy adoption by workers previously unfamiliar with the basic technic and apparatus. It has been subjected to more rigorous quality control by blind and double-blind trials concurrent with ordinary routine work than is usual, and has passed these tests adequately. Data processing by a small, relatively inexpensive digital computer is capable of handling the data produced by the central apparatus of the method. The sensitivity of newer instruments using well-established fluorescence reactions compares very favorably with that of flame-ionization detectors in gas-liquid chromatography but not with the electron-capture detector as yet.
Manual Fluorometric Paper Disc Method for Determining Tyrosine in Blood
Authors: Searle Bernard G , Li Miyako , Briggs Jamalabo , Segall Paul , Widelock Daniel , Davidow Bernard 
Published: January 2020

Abstract
A spectrophotofluorometric method is described for the determination of tyrosine in blood dried on filter paper discs. It has been found that by immersing the paper disc containing the dried blood in aqueous trichloracetic acid, the blood proteins remain bound to the paper and the amino acid is eluted into the aqueous phase. This method of assay is based on the principle that tyrosine reacts with α-nitroso-β-naphthol to form a highly fluorescent product.
Determination of Uric Acid An Automated Phosphotungstate Method Using NaOH as the Alkali
Authors: Wheat James L 
Published: January 2020

Abstract
An automated method is described for the determination of serum uric acid using sodium hydroxide alone as the alkalinizing agent in the uric acid-phosphotungstate reaction. Turbidity is not a problem and antiturbidity reagents are not needed. At the rate of 40 samples per hour, there is good sensitivity and good correlation with a manual urea-cyanide method. Quality control shows a standard deviation of ± 0.1 mg./100 ml.
Ionic Activities of Sodium, Potassium, and Chloride in Human Serum
Authors: Dahms Harold , Rock Robert , Seligson David 
Published: January 2020

Abstract
Ionic activities of sodium, potassium, and chloride in serums of 26 hospitalized patients were determined with ion-specific electrodes. Comparison of the activities with the corresponding concentrations shows that the two most important parameters influencing the molar activity coefficients of these ions are the water content of serum and the binding between albumin and chloride. Quantitative expressions for activity-concentration conversion factors are given. Calculations show that the conversion factors vary significantly in disease states due to changes in protein.
Acid Hydrolases in Plasma in Gaucher’s Disease
Authors: Ockerman P A , Kohlin P 
Published: January 2020

Abstract
Acid hydrolytic enzymes were measured in plasma from 6 patients with Gaucher’s disease. Markedly increased values were found not only for acid phosphatase, as expected, but also for β-acetylglucosaminidase and β-glucuronidase. The activity of β-galactosidase and α-fucosidase was slightly increased, and that of α-mannosidase was normal.
A New and Rapid Determination of Pyridinium Aldoximes in Blood and Urine
Authors: Groff William A , Ellin Robert I 
Published: January 2020

Abstract
A rapid and accurate method for analyzing pyridinium oximes—N-methylpyridinium-2-aldoxime chloride, N,N'-trimethylene-(pyridinium-4-aldoxime) dihalide, and N,N'-oxydimethyl-(pyridinium-4-aldoxime) dichloride—in plasma, urine, and whole blood is described. The method is completely automated and requires small sample volumes. Concentrations ranging from 3 to 120 µEq./L. in biologic fluids can be determined at a rate of 40 samples per hour. This technic can be applied to oximes which are unstable in basic solution. The average variation of the oxime concentration used to establish calibration curves, as determined by the ratio of the standard deviation to the mean, was ± 1.5%. Plasma and albumin increase the transfer rate of the oximes through the dialyzing membrane. Theoretical concentrations to explain this phenomenon are presented.
Application of a Continuous Spectrophotometric Assay for 5'Nucleotidase Activity in Normal Subjects and Patients with Liver and Bone Disease
Authors: Belfield Alan , Goldberg David M 
Published: January 2020

Abstract
Serum 5'nucleotidase activity has been measured by a coupled kinetic assay in which adenosine formed by hydrolysis of adenosine 5'-monophosphate in the presence of 150-fold excess of β-glycerophosphate is converted to inosine by adenosine deaminase, with a consequent decrease in absorbance at 265 nm. The method gives activity in proportion to enzyme concentration so long as the rate of decrease of absorbance at 265 nm does not exceed 0.025/min, and not more than 30% of the substrate is consumed. The normal range established in 517 healthy adults was 0-15 mU/ml. A significant correlation between enzyme activity and age was found in females but not in males. Raised levels of 5'nucleotidase activity were found in 92% of patients with obstructive jaundice, 70% of patients with parenchymal liver disease, 81% of patients with hepatic metastases, and 11% of patients with bone disease. The estimation is useful in aiding the elucidation of raised serum alkaline phosphatase activity, and is of value as a liver function test, but is not as frequently increased as alkaline phosphatase in all classes of hepatobiliary disease.
A Simplified Fluorometric Method for Determination of Plasma Methotrexate
Authors: Chakrabarti Siba G , Bernstein I A 
Published: January 2020

Abstract
A method is described for the determination of plasma methotrexate at low concentrations. The method consists of a single fluorescence measurement on plasma proteinfree filtrates after oxidation of the drug with KMnO4 at controlled pH. The complete release of the drug into plasma filtrates is accomplished by heating the reaction mixture in a boiling water bath with occasional stirring.
An Automated Method for Serum Calcium Utilizing Ethylene Diamine Tetraacetic Acid
Authors: Burr Robert G 
Published: January 2020

Abstract
An improved method of estimating serum calcium by the AutoAnalyzer using the reagent glyoxal-bis-(2-hydroxyanil) is described. Sensitivity and accuracy in the physiological range are increased by the use of ethylene diamine tetraacetic acid. Results correlate well with an established manual procedure and there is no interference from magnesium or phosphate.
A Summation Technic for Serum Total Lipids
Authors: Cheek Chandler S , Wease Dorothy F 
Published: January 2020

Abstract
An efficient summation technic for the quantitation of total lipid from the results of the cholesterol, phospholipid, and triglycerides determinations is compared to the phenol turbidity and gravimetric method. Also considered is the total lipid value calculated from the cholesterol and triglyceride concentrations.
Studies on Manganese
Authors: Mahoney John P , Sargent Kathleen , Greland Margaret , Small Walter 
Published: January 2020

Abstract
Atomic absorption spectrophotometry offers a method applicable to the determination of serum manganese in clinical research. The signal-to-noise ratio is great enough to yield precise data even with 10X scale expansion. The method has the required sensitivity for the measurement of the concentrations encountered in human serum, even though the signals produced are very small. It requires a few manipulative steps, and the possibility of contamination is kept to a minimum. Interference from other materials usually present in the matrix does not present a problem.
The mean manganese concentration in the serum of normal fasting human subjects was 2.4 ± 0.7 µg/100 ml without any variation between the sexes. The concentration in the same individual does not vary over long periods of time. Initial observations do not indicate diurnal variation.
Large quantities of manganese administered to two normal individuals for 3 and 8 weeks, respectively, did not produce a detectable change in the serum manganese concentrations.
Studies are underway to adapt the method to the determination of manganese in blood cells and other tissues.
Fluorometric Determination of Histidine
Authors: Ambrose John A , Crimm Allan , Burton Joe , Paullin Kathleen , Ross Charlotte 
Published: January 2020

Abstract
An accurate and precise fluorometric procedure was developed for the determination of histidine based on the observation that o-phthalaldehyde forms a fluorophor with the analogous compound, histamine. The precision of the method was improved, and the fluorophor was stabilized for days by the addition of a phosphoric acid reagent.
A New Method for Serum Iron and Total Iron-Binding Capacity by Atomic Absorption Spectrophotometry
Authors: Olson Arthur D , Hamlin W B 
Published: January 2020

Abstract
A new, atomic absorption spectrophotometric method for serum iron and iron-binding capacity is described, which utilizes 20% (w/v) TCA plus heating at 90° for 15 min. This procedure liberates the ferric iron; precipitates the protein, facilitating removal by centrifugation; and avoids significant interferences by contaminating hemoglobin iron. The method is highly specific, accurate, and has the additional feature of requiring less time than most colorimetric or atomic absorption methods employing chelation and extraction.
Automated Fluorometric Determination of Glucose-6-Phosphate Dehydrogenase (G6PD) and 6-Phosphogluconate Dehydrogenase (6PGD) Activities in Red Blood Cells
Authors: Tan I K , Whitehead T P 
Published: January 2020

Abstract
An automated fluorometric microtechnic, suitable for screening purposes, has been developed for the quantitative determination of glucose-6-phosphate dehydrogenase (G6PD) and 6-phosphogluconate dehydrogenase (6PGD) levels in red blood cells. The method is rapid, simple, and precise. It uses 50 µl whole-blood (capillary) samples and is based on the measurement of natural fluorescence emitted by the NADPH generated during the enzymatic reactions.
Evaluation of a New System for the Kinetic Measurement of Serum Glutamic Oxalacetic Transaminase
Authors: Winsten Seymour , Wilkinson J Henry , Boutwell Joseph H 
Published: January 2020

Abstract
A new spectrophotometric method for the determination of serum glutamic oxalacetic transaminase§ (SGOT) is described which uses standardized technics and prepackaged reagents. A study was made of this new method in three laboratories and was compared with the routine methods, using identical serum specimens. The new procedure gave good reproducibility and precision. In all methods studied there was evidence of failure of linearity of response at the two highest activity levels examined.
Specific Binding Radioassay of Serum Thyroxine
Authors: Nobel Sidney , Barnhart Fay 
Published: January 2020

Abstract
Adaptation of the Murphy and Jachan method for serum thyroxine for routine use in a clinical chemistry laboratory is described. Details in the original paper have been amplified, and operations such as mixing, resin addition, and temperature control modified in the direction of greater precision and simplicity. A comparison study was made of the performance of the method in our laboratory with the reported performance in the laboratory of the original authors. In agreement with Murphy and coworkers and Cassidy et al, it was found that conditions could be established whereby the method was both reproducible and capable of yielding significant diagnostic information in the presence of iodinated radiographic compounds.
Effect of Bilirubin and Lipemia on an Automated Method for Serum Cholesterol
Authors: Moline Carolyn , Barron Edward J 
Published: January 2020

Abstract
A simple automated procedure for total serum cholesterol, employing a stable Liebermann-Burchard reagent, was tested. The method has good precision, and results agree well with extraction methods for total cholesterol on normal serums. Serum samples with elevated bilirubin levels gave cholesterol values which were too high and which could not always be corrected for. Lipemic serums in some instances gave results which were too low when compared to other methods.
A Simple and Sensitive Method for the Measurement of Deoxycytidylate Deaminase Activity
Authors: Ressler Newton 
Published: January 2020

Abstract
A method for the assay of deCMP deaminasef based upon the measurement of ammonia formation by means of the Berthelot reaction is described. Saturating con-centrations of substrate are used. The activity is linear with time for several hours, and with enzyme concentration. Composition of the incubation medium, repro-ducibility, and enzyme stability are studied. The method is reasonably simple to perform, reproducible, and sensitive. Values obtained with some normal tissues and serum are presented, and the possible significance of measurable activity in human serum is discussed.
Automatic Discrete Sample Processing: Automation in a Clinical Chemistry Laboratory Based on Discrete Sample Handling and Computerized Data Processing
Authors: Westlake George , McKay Donald K , Surh Philip , Seligson David 
Published: January 2020

Abstract
It is our belief that a general-purpose digital computer that receives and processes the electrical signal from an analytic instrument to its final step, and then processes the latter to produce a patient report, is an essential tool of the clinical laboratory. The present report concerns the development of a discrete-sample-handling analytic instrument that was designed to interface with a computer. A description is given of the entire system that includes the interface, multiplexing, sample identification, and operational characteristics of the instrument. Some advantages of discrete sample handling in analytic chemistry are accuracy, speed, ease of adaptation to computers, use of small amounts of sample, stepwise analysis of analytic method, and ease of trouble-shooting.
Quantification of Protein Solutions with Trinitrobenzenesulfonic Acid
Authors: Goodwin Jesse F , Choi Siu-Ying 
Published: January 2020

Abstract
Trinitrobenzenesulfonic acid (TNBS) may be used for quantifying dilute solutions of protein. The trinitrophenyl protein—sulfite complexes resulting from reaction of TNBS with protein in the presence of sulfite are highly colored and exhibit maximum spectral absorbance at 420 nm. The TNBS protein—sulfite complex is formed by a simple two-stage condensation and complexation reaction. Protein in concentrations as low as 20 µg may be detected by the reaction. The method devised for protein quantification compares favorably with an ultraviolet spectrophotometric method and the conventional biuret procedure. Bilirubin and hemoglobin interference with the TNBS method is negligible. The procedure is useful for measuring total protein and globulin in serum and cerebrospinal fluid and also for measuring minor serum protein components. Procedural parameters and factors affecting the measurement of protein by the TNBS—sulfite reaction are presented.
Chemical Basis of the Carbamidodiacetyl Micromethod for Estimation of Urea, Citrulline, and Carbamyl Derivatives
Authors: Veniamin Michael P , Vakirtzi-Lemonias Catherine 
Published: January 2020

Abstract
The chemical pathway of the carbamidodiacetyl colorimetric assay was investigated. The experimental variables that were studied include reaction temperature, heating time, and the ratio of the mineral acid mixture to the reactants. Evidence is presented establishing the involvement of either 7- or 8-methyl, or 7,8-dimethyltetrahydroimidazo(4,5-d)imidazole-2,5-diones as chromogens, all three being equally acceptable.
New Chromogenic Substrate for Determination of Serum Amylase Activity
Authors: Klein Bernard , Foreman James A , Searcy Ronald L 
Published: January 2020

Abstract
A rapid assay for serum amylase activity has been developed based on the use of a new chromogenic substrate—Cibachron Blue—amylose. The procedure requires 0.1 ml of serum and measures the production of soluble chromogen, the formation of which is linear with enzyme activity. Normal human serum has a mean amylase activity of 118 ± 37 (SD) mg dye/100 ml/15 min or, in international units, 78 ± 24 (SD) µg dye/min/ml. Excellent correlation was observed with a saccharometric amylase procedure.
Amino Acid Composition of Serum Albumin in Normal Individuals And in Patients with Rheumatoid Arthritis
Authors: Denko Charles W , Purser D Barrie , Johnson Ralph M 
Published: January 2020

Abstract
A modern automated technique has been used to re-evaluate the older standard classic methods for studying the amino acid composition of human albumin. Previous published data have been derived from pooled samples that included persons of unknown clinical status. In this study normal values were determined for albumin derived from healthy volunteers and purified by electrophoresis on polyacrylamide gel. Patients with rheumatoid arthritis were similarly evaluated. No differences attributable to age were found. Albumin from women contained 20% more threonine than did albumin from men. Patients with rheumatoid arthritis had more phenylalanine and less lysine in their albumin than did normal persons. No such differences in composition of structural proteins have been previously demonstrated. It is unlikely that the substitution of one amino acid for another in molecules of this size could arise by chance during protein synthesis.
Optimization of Radioimmunoassay for Human Growth Hormone by the Charcoal-Dextran Technique
Authors: Meek Joseph C , Stoskopf Mary M , Bolinger Robert E 
Published: January 2020

Abstract
The effect of serum on the radioimmunoassay for human growth hormone was tested by use of the double-antibody technique and the charcoal-coated dextran technique. With the double-antibody technique, serum effects a falsely high reading for unknowns, while with the charcoal-dextran technique it causes falsely low values to be obtained. Part of the anomaly with the charcoal-dextran technique is the result of adsorption of small molecular fragments of radiolabeled hormone onto serum proteins of higher molecular weight. These fragments can be eliminated by frequent repurification of the labeled hormone. Another part is not related to purity of the label but is corrected by subtracting values for serum blanks that contain no antibody. The use of antiserum to human growth hormone prepared in the goat is more sensitive than that prepared in the guinea pig.
An Artifact in the Analysis of Oxygenated Blood for Its Low Carbon Monoxide Content
Authors: Lee Rodkey F , Collison Harold A 
Published: January 2020

Abstract
A sensitive gas chromatographic method for blood CO determination was used to analyze samples of reduced and oxygenated blood having identical low CO content. Oxygenated blood always released more CO than did the reduced samples when neutral ferricyanide was used as oxidant. Several reagents for CO release from blood were applied to both oxygenated and reduced samples. CO release by K3Fe(CN)6 from oxygen-free blood or COHb solutions was complete and constant from pH 1.5 to 6. Values of extra CO released from oxygenated samples varied from 0.003 vol % at pH 1.5 to over 0.015 vol % at pH 6. The least amounts of excess CO were produced between pH 2 and 4.5. Neutral K2Cr2O7 causes less excess CO formation than does K3Fe(CN)6, but the rate of reaction with COHb is low. Neutral KMnO4 and acid K2Cr2O7 cause extreme formation of excess CO from blood in amounts many times the amount of COHb present. Acid KIO3 effectively releases CO from COHb solutions and reduced blood, but causes more excess CO formation from oxygenated blood than K3Fe(CN)6. When CO is released in citric acid with K3Fe(CN)6 at a pH of about 3.5, the CO released from oxygenated blood is only about 0.001 vol % greater than that released from reduced samples. These differences indicate formation of small amounts of CO during reactions used to release CO from blood. Reduced hemoglobin and carboxyhemoglobin appear to be much more stable to these procedures than is oxyhemoglobin.
Quantitative Determination of Chlorpromazine Metabolites in Urine
Authors: Turner William J , Turano Patricia A , March James E 
Published: January 2020

Abstract
A simple, rapid, precise, and accurate method is described for the simultaneous and quantitative determination of conjugated and unconjugated chlorpromazine metabolites in urine. It depends on reduction of sulfoxides to sulfides, and oxidation of sulfides to ion radicals in a solution of Fe+3 (10-3N) in 18N H2SO4. Absorbance is measured at 422, 530, 565, and 700 nm, and concentration of metabolites is calculated by substituting values obtained in appropriate equations. Our data for urines (from schizophrenic men chronically medicated with chlorpromazine) generally agree with those of other workers.
Thin-Layer Chromatography of Urinary Carbohydrates
Authors: Young D S , Jackson Agathe J 
Published: January 2020

Abstract
Ten procedures for thin-layer chromatography of carbohydrates in urine were compared. The procedures differ considerably in their sensitivity and ability to separate sugars of clinical importance. A procedure was developed that permitted several sugars to be identified in normal urine samples without prior desalting or concentration. Celite was used as adsorbent, anisaldehyde as location reagent. The procedure is simple and reproducible, and is readily modifed for quantification of sugars by thin-layer densitometry.