bluuebunny/crossref_metadata_2025_split huggingface dataset:
Continuous-Flow Measurement of Lactate in Blood: A Technique Adapted for Use in the Emergency Laboratory
Authors: Boycks Edward , Michaels Sybil , Weil Max Harry , Shubin Herbert , Marbach Edward P 
Published: January 2020

Abstract
This automated enzymatic method for analysis of lactate in blood, adapted from a manual method, is designed for use with an AutoAnalyzer. Start-up time is 5 min. After a time delay of 4 min, 99 samples may be analyzed per hour. Recovery averaged 100.7% (range, 99.6-101.8%). Reproducibility was within 1 SD (equivalent to 70 µmol/liter). Reagents are stable at room temperature for one month. The procedure has been in continuous use as an emergency test in support of emergency and critical care for three years, during which time we have done more than 10 000 determinations.
Inactivated Serum vs. Saline as a Diluent in Some Serum Enzyme Assays
Authors: Fendley Ted W , Frings Christopher S 
Published: January 2020

Abstract
In assays of creatine kinase (EC 2.7.3.2), alkaline phosphatase (EC 3.1.3.1), lactate dehydrogenase (EC 1.1.1.27), or asparate aminotransferase (EC 2.6.1.1) activities by certain end-point methods, we found no significant difference in the accuracy and precision of the results when serum was diluted with heat-inactivated pooled serum or NaCl solution (8.5 g/liter). For creatine kinase, asparate aminotransferase, and alkaline phosphatase, correlations were good for the two diluents, but poor in the case of lactate dehydrogenase.
Unusual Variant of Lactate Dehydrogenase Isoenzymes
Authors: Buchholz D H , Donabedian R K 
Published: January 2020

Abstract
Thirteen electrophoretic bands of lactate dehydrogenase isoenzyme activity were detected in the serum of a 69-year-old Negro woman who died of pseudomonas pneumonia. No evidence of tumor was found at necropsy, and additional studies of the enzymatic activity of crude extracts of liver, lung, spleen, kidney, brain, skeletal muscle, lymph node, and heart revealed 1, 2, 3, 4, and 5 separate isoenzyme bands for lactate dehydrogenase isoenzymes 1, 2, 3, 4, and 5, respectively (a total of 15 isoenzyme bands). Serum and erythrocyte hemolysate from one of two healthy daughters displayed a similar pattern of multiple isoenzyme bands in isoenzymes 2 and 3. The observed pattern is consistent with the heterozygous form of a mutation of the genetic locus controlling synthesis of the M monomer such that two differently charged monomeric proteins are produced, each of which apparently combines with H chains with equal facility, leading to the multiband enzymatic specificity seen.
Concepts for the Rational Selection of Assays to Be Used in Monitoring Therapeutic Drugs
Authors: Werner Mario , Sutherland Earl W , Abramson Fred P 
Published: January 2020

Abstract
As the domain of monitoring therapeutic drugs rapidly expands from experimental investigations to everyday patient care, all clinical laboratory scientists, but especially clinical chemists, must learn to deal with their involvement in this expansion. First, the theoretical concepts underlying clinical pharmacology must be appreciated so that the laboratory's participation in it can succeed. Individual differences cause unpredictable variations of response to the customarily standardized drug dosage. Properly used, assays of drugs in blood can eliminate such variabilities. Second, the practical selection of which drug assays a laboratory intends to provide must be based on a rational evaluation of assay usefulness, integrating both clinical and laboratory considerations. Such a decision model is suggested; it is generally applicable in allocating priorities among an ever-increasing number of proposed tests under the constraint of finite resources.
Solid-Phase Radioimmunoassay of Thyroxine in Untreated Serum
Authors: Seth John , Rutherford Frederick J , McKenzie Ian 
Published: January 2020

Abstract
We describe a simple, convenient solid-phase radioimmunoassay of total thyroxine in unextracted serum. Serum samples are added directly to the assay incubation mixture, interference in the antigen/antibody reaction by the thyroxine-binding serum proteins being almost completely eliminated by the addition of 8-anilino-1-naphthalene sulfonic acid and incubation at pH 10.5. Residual interference is compensated for by including thyroxine-free serum in the standards. Use of thyroxine antibodies that are coupled to a solid support permits separation of free and antibody-bound hormone by a single washing step, followed by centrifugation. The method is specific, accurate, and reasonably precise. The results obtained compare well with those for radioimmunoassay of thyroxine in serum freed of protein by gel filtration, and with results of a competitive protein-binding method. The technical simplicity of the procedure should readily permit automation. These features suggest that the technique should be well suited for routine clinical laboratory use.
Use of the Reference Method for Determination of Serum Calcium in a Quality-Assurance Survey
Authors: Pickup John F , Jackson Malcolm J , Price E Margaret , Healy Michael J R , Brown Stanley S 
Published: January 2020

Abstract
The Reference Method [Clin. Chem. 19, 1208 (1973)] for determination of total calcium in serum has been applied to 29 specimens from the Wellcome Group Quality-Control Programme. The accuracy of the mean resuIts for all participants, and for selected groups of participants, was determined over the concentration range 2.00-2.75 mmol/liter. We show that, in general, continuous-flow (AutoAnalyzer) and atomic absorption methods of analysis have a small, constant bias, but chelation (ethylenediaminetetraacetate) methods are unpredictably inaccurate.
Colorimetric, Enzymatic, and Liquid-Chromatographic Methods for Serum Uric Acid Compared
Authors: Slaunwhite W David , Pachla Lawrence A , Wenke David C , Kissinger Peter T 
Published: January 2020

Abstract
We describe high-performance liquid chromatography in conjunction with electrochemical detection as a possible reference method for serum uric acid. Separation was effected on a column packed with "Vydac" strong anion-exchange resin, with use of a detection potential of +0.80 V vs. an Ag/AgCl reference electrode. Results were linearly related to concentration up to 1.0 g/liter, and no interferences were seen. Assay of human sera gave within-run and day-to-day coefficients of variation of 0.83% and 1.1%, respectively; analytical recoveries averaged 100%. Comparison of the new procedure (x) with the phosphotungstate and uricase methods (y) showed the following linear regression and correlation coefficients for results: y = 0.963x + 0.219 (r = 0.995), and y = 0.991x + 0.165 (r = 0.999), respectively. As compared to these methods, the procedure we describe is more accurate, because of the selective detection system based on retention time and redox potential. Samples can be analyzed at the rate of 20/h. No deproteinization is required.
Simplified Photometric Copper-Soap Method for Rapid Assay of Serum Lipase Activity
Authors: Myrtle James F , Zell Wilbert J 
Published: January 2020

Abstract
We modified the method of Yang and Biggs [Clin. Chem. 17, 512 (1971)] for greater speed and simplicity. Serum is incubated with an emulsified olive oil substrate, the fatty acids extracted, the copper soap formed, and phases separated, all in a single tube. An aliquot of the organic phase is removed for color development. One analysis can be completed in 35 min, 20 in less than 2 h. The method is accurate and precise. Results correlate well with the unmodified colorimetric method, and with the classical titrimetric lipase procedure. The reference interval (normal range) is 20 to 180 U/liter.
Evaluation of the ABA-100 Procedure for Total and Direct Bilirubin in Serum or Plasma
Authors: Jaberg Clair , McConnell Kay , Potter Joseph L , Platt Marvin S 
Published: January 2020

Abstract
We present a modified Evelyn-Malloy method, adapted to the Abbott Biochromatic Analyzer (ABA-100) for the determination of both total and direct bilirubin. It requires less than 25 µl of serum or plasma. At least 50 samples can be assayed per hour with economy of reagent consumption and the precision compares favorably with that for conventional manual methods.
Correlation of Selected Serum Constituents: 1. Inter-Individual Variation and Analytical Error
Authors: Winkel Per , Statland Bernard E , Bokelund Henning , Johnson Eugene A 
Published: January 2020

Abstract
The intra-subject correlations of three clinically meaningful combinations of serum constituents—(a) potassium, calcium, and albumin; (b) urea, creatinine, and uric acid; and (c) aspartate aminotransferase, lactate dehydrogenase, and alkaline phosphatase—were studied in 11 healthy men. Duplicate serum samples were obtained at 800 h, 1100 h, and 1400 h on five different days. All assays were performed on the AutoChemist Multichannel Analyzer. Correlation coefficients differed significantly among the subjects for the following six pairs of serum constituents: urea and creatinine, urea and uric acid, creatinine and uric acid, aspartate aminotransferase and lactate dehydrogenase, aspartate aminotransferase and alkaline phosphatase, and lactate dehydrogenase and alkaline phosphatase. Nonbiological positive correlation between analytical errors (i.e., errors of two different assays performed on the same specimen) was demonstrated for two of the pairs: potassium and calcium, and aspartate aminotransferase and lactate dehydrogenase. The error correlations of these two pairs of constituents comprised a significant component of the observed intra-subject correlations. Probable reasons for these analytical error correlations are discussed
Simple, Highly Selective Screening Method for Barbiturates in Urine
Authors: Pehr František 
Published: January 2020

Abstract
I present a new, simple colorimetric method for detecting and estimating barbiturates in urine. After the barbiturates are extracted with ether, an aliquot of the washed ether phase is added to the color reagent (a bivalent mercury/dithizone chelate in chloroform). On addition of diluted pyridine and shaking, a pinkish-violet color appears if a barbiturate is present. The overall sensitivity of the above method was evaluated by probit analysis in the case of sodium phenobarbital. The concentration of sodium phenobarbital in urine detectable at least 99% of the time was 6.72 mg/liter, with 95% confidence limits of 5.37 to 10.36 mg/liter. Sodium phenobarbital, 10 mg/liter, can be detected in the presence of phenytoin (50 mg/liter), glutethimide (100 mg/liter), or bemegride (100 mg/liter). The whole procedure requires &lt;10 min. An excretion study illustrates application of the procedure
Reaction-Rate Assay of Serum Sorbitol Dehydrogenase Activity at 37 °C
Authors: Rose Clive I , Henderson Arthur R 
Published: January 2020

Abstract
The sorbitol dehydrogenase (EC 1.1.1.14) activity of human serum and liver was investigated at 37 °C. Various buffers were examined but tris(hydroxymethyl)aminomethane HCl in a final concentration of 90 mmol/liter (pH 6.6, at 37 °C) was the one with which activity was the greatest. The enzyme is inhibited by its substrate, D-fructose, and activity was greatest with a substrate concentration (in the final assay mixture) of 500 mmol/ liter and an NADH concentration of 247 µmol/liter. The specimen volume was 100 µl. The enzyme from liver and serum was shown to have similar Km values and activation energies, and we conclude that the liver enzyme was unchanged on passing into the extrahepatic space. Normal values for this assay are 0-2.6 U/liter (2.5 and 97.5 percentiles)
Specificity of Oxidation of Bile-Salt Hydroxyl Groups by Crude Extracts of Pseudomonas Testosteroni (ATCC 11996) Used in Determining Bile Salts
Authors: Beher William T , Lin Grace J 
Published: January 2020

Abstract
Recent experimental evidence suggests that, presumably as a result of mutation, crude extracts of Pseudomonas testosteroni (ATCC 11996) now contain amounts of 7α-and 12α-hydroxysteroid dehydrogenate activity that invalidate the results of bile-salt determinations. To confirm or deny this, we studied the specificity of hydroxysteroid dehydrogenase contained in crude extracts of currently available samples of this bacterium in the oxidation of bile-salt hydroxyl groups. The dehydrogenases in these extracts specifically oxidized 3α-hydroxyl groups of cholate, chenodeoxycholate, and deoxycholate anions. No significant amount of 12α-or 7α-hydroxysteroid dehydrogenase activity was detected. Currently available crude extracts of Pseudomonas testosteroni (ATCC 11996) are therefore suitable for bile-salt quantification
Simple, Sensitive Method for Measuring Plasmin and Plasminogen Activity in Plasma
Authors: Uete Tetsuo , Shimano Noriko , Morikawa Mamiko 
Published: January 2020

Abstract
We describe a sensitive, simple, and rapid method for measuring plasmin and plasminogen in plasma, with fibrinogen as substrate. The assay can be done within 1 h. Plasma is diluted 20-fold with buffer and 0.1 ml (5 µl of original plasma) is incubated for 5 min at 37 °C, with or without 400 units of streptokinase. Then 2.0 ml of fibrinogen solution is added, the mixture again incubated (37 °C, 5 min), and the reaction stopped. The amount of tyrosine liberated from the fibrinogen is measured and is related to activity. This method is suitable for routine clinical work if the same batch of fibrinogen is used
Fluorometric Determination of "Albumin-Titratable Bilirubin" in the Jaundiced Neonate
Authors: McCluskey Susan B , Storey G N B , Brown G K , More D G , O’Sullivan W J 
Published: January 2020

Abstract
We report a fluorometric technique for determination of albumin-titratable bilirubin in the jaundiced neonate. Although bilirubin alone has very little native fluorescence, considerable emission is observed in the presence of albumin under acid conditions. Analysis of the plasma sample alone and in the presence of excess human serum albumin solution appears to reflect the bilirubin tightly bound to albumin and the total serum bilirubin, respectively. The difference between these two values has been designated as "albumin-titratable bilirubin." Where the concentration of albumin-titratable bilirubin is considerable, a typical saturation effect is observed. In samples where the circulating bilirubin is strongly bound to endogenous albumin, no change in fluorescence is seen when exogenous albumin is added. Results correlate well with the clinical picture
Therapeutic Monitoring of Anticonvulsant Drugs: Gas-Chromatographic Simultaneous Determination of Primidone, Phenylethylmalonamide, Carbamazepine, and Diphenylhydantoin
Authors: Least Charles J , Johnson George F , Solomon Harvey M 
Published: January 2020

Abstract
We describe a sensitive and precise gas-chromatographic method in which benzylmalonate methylester monoamide is used as the internal standard for the simultaneous determination of primidone, phenylethylmalonamide, carbamazepine, and diphenylhydantoin. The trimethylsilyl derivatives of the anticonvulsants are well separated from each other and from normal serum constituents. The lower limit of detection for each drug is 0.5 mg/liter when 1 ml of serum is analyzed. Withinrun precision (CV), established by analysis of 10 replicates, was as follows: primidone (5.4 mg/liter), 2.6%; phenylethylmalonamide (5.5 mg/liter), 1.6%; diphenylhydantoin (6.6 mg/liter), 3.8%; and carbamazepine (10.4 mg/liter), 3.2%. Fifty specimens were analyzed for primidone and 35 for diphenylhydantoin by a standard gas-chromatographic method involving on-column methylation and by the procedure we have developed. The mean value observed for primidone with the on-column alkylation procedure was 9.3 mg/liter and with our procedure was 9.6 mg/liter. When values for our assay were regressed against values for the standard method, the slope of the least-squares line was 0.936, the intercept was 1.00 mg/liter, and r was 0.939. The mean values observed for diphenylhydantoin by on-column methylation and with our procedure were both 12.6 mg/liter. When values for our assay were regressed against the standard method, the slope of the leastsquares line was 0.944, the intercept was 0.3 mg/liter, and r was 0.988
Measurement of Brain-Specific Creatine Kinase Isoenzyme Activity in Serum
Authors: Nealon Daniel A , Henderson Arthur R 
Published: January 2020

Abstract
We further modified a diethylaminoethyl-cellulose column-chromatographic system [Clin. Chem. 21, 392 (1975)] so that it will separate all three serum creatine kinase isoenzymes. The modified system can be used to detect brain-specific creatine kinase isoenzyme in serum after brain surgery
Colorimetric Measurement of Ornithine Carbamoyl Transferase Activity in Plasma, and Results for a Supposedly Healthy Population
Authors: Bagrel Alain , Museur Gérard , Siest Gérard 
Published: January 2020

Abstract
Determination of ornithine carbamoyl transferase (EC 2.1.3.3) activity in plasma is important for detection of liver diseases. The assay established in this paper has been made optimum. A blank is needed containing both substrates, carbamoyl phosphate and ornithine. We used a new colorimetric assay, based on a complex with a phosphoferric-antipyrine reagent and diacetyl monoxime, to measure the citrulline formed. The highly sensitive assay permits low activities to be determined accurately. Values for blood plasma from 425 supposedly healthy people, varied from 0 to 16 U/liter (95th percentile), and 27% of this population showed an activity of less than 2 µmol of citrulline formed per minute per liter, 2 U/liter being the limit of the method’s sensitivity.
Evaluation of Kinetic Light Scattering as an Approach to the Measurement of Specific Proteins with the Centrifugal Analyzer. I. Methodology
Authors: Buffone Gregory J , Savory John , Cross R E , Hammond J E 
Published: January 2020

Abstract
A laser-modified centrifugal analyzer was used to develop kinetic light scattering methods for the measurement of human immunoglobulins IgG, IgA, and IgM. Comparison of equilibrium light scattering methods with kinetic procedures for IgG and IgA demonstrate equivalent precision and relative accuracy. However, quantitative results obtained by equilibrium and kinetics methods for IgM were found to differ significantly. Recovery studies performed with purified IgM have shown that both methods can yield quantitative results in the normal range. Our observations demonstrate that the technique offers a viable and in some respects a superior alternative to other methods currently used in the clinical laboratory.
Evaluation of Kinetic Light Scattering as an Approach to the Measurement of Specific Proteins with the Centrifugal Analyzer. II. Theoretical Considerations
Authors: Buffone Gregory J , Savory John , Hermans J 
Published: January 2020

Abstract
Development of centrifugal analyzers capable of making light-scattering measurements has prompted the investigation of the application of this type of instrumentation to the measurement of specific proteins. Investigation of antigen/antibody complex dimension and the kinetics of the IgG/anti-IgG reaction as followed by light scattering are examined in relation to improved analytical methodology. The effect of nonspecific protein on the reaction rate has been investigated for IgM, and data are presented that provide insight into the mechanism of the effect of periodic mixing.
Evaluation of Trinder's Glucose Oxidase Method for Measuring Glucose in Serum and Urine
Authors: Lott John A , Turner Kathie 
Published: January 2020

Abstract
Trinder's method for glucose has nearly all the attributes of an ideal automated colorimetric glucose oxidase procedure. The chemicals used in the color reaction with peroxidase are readily available, the solutions are stable and can be prepared by the user, the method is highly specific and largely free of interferences, the sensitivity can be adjusted by the user to cover a wide range of glucose concentrations, and the reagents are not hazardous. We found very good agreement between results by this method and by the hexokinase and Beckman Glucose Analyzer methods. The method has been modified and adapted to the AutoAnalyzer I and SMA 6/60 (Technicon) with manifolds that give very little interaction between specimens. A study of the method by the simplex technique revealed that the glucose oxidase activity in the reagent is the most critical variable.
Scatchard Plot and Heterogeneity in Binding Affinity of Labeled and Unlabeled Ligand
Authors: Hollemans H J G , Bertina R M 
Published: January 2020

Abstract
In saturation analysis the Scatchard plot is a generally accepted method for calculation of the affinity constant, K, and the molar concentration, q, of the binder. However, in a system where the K's for the labeled and unlabeled ligand are unequal, a nonlinear plot can be obtained from which incorrect values for K and q may be calculated. This paper mathematically explains how the plot may deviate and under which conditions there will be a maximum in the curve. When the binding sites are homogeneous, the coordinates of this maximum can be used to calculate K and q. A general mathematical expression is derived on the basis of which a linear curve can be constructed for calculation of q and K, which is valid even when affinity for the labeled and unlabeled ligand is not identical.
Fluorometric Assay of Serum Acid or Alkaline Phosphatase, Either in Solution or on a Semisolid Surface
Authors: Rietz Bernd , Guilbault George G 
Published: January 2020

Abstract
We describe enzymatic fluorometric methods for determining activities of serum alkaline phosphatase and of serum acid phosphatase in solution and on silicone rubber pads. 4-Methylumbelliferone phosphate is used as substrate, in either tris(hydroxymethyl)aminomethane or citrate buffer. In solution, the reaction is measured at 37 °C in a 3-ml Pyrex cuvette. Measurements on the pads are also made at 37 °C, after establishing a stable substrate film by lyophilizing all reagents on the surface of the pads. Only 20 to 30 µl of substrate solution, 50 µl of buffer solution, and 1 to 10 µl of blood are necessary, making a total volume of 51 to 60 µl for each assay. The rate of appearance of the fluorescent 4-methylumbelliferone liberated from 4-methylumbelliferone phosphate by the enzymatic action is measured and equated to enzyme activity. Calibration plots of the change in fluorescence per minute vs. enzyme activity for measurements in solution and on pads show a good proportionality in the range of 30.8 to 633 U/liter for alkaline phosphatase and in the range of 0.265 to 5.3 King— Armstrong units for acid phosphatase, indicating the usefulness of these methods in the clinical laboratory.
Direct Radioimmunoassay for Unconjugated Estriol in Pregnancy Serum, with Use of a Radioiodinated Derivative of Estriol
Authors: Miller Carol A , Fetter Marion C , Boguslaski Robert C 
Published: January 2020

Abstract
We describe a rapid and direct 125I-based radioimmunoassay for quantification of unconjugated (free) estriol in pregnancy serum. Estriol in serum is adsorbed onto a small column of Sephadex, thereby allowing its separation from proteins and interfering materials. A radioiodinated derivative of estriol (6-ketoestriol-6(o-carboxymethyl)oxime-[125I] tyrosine methyl ester) is added to the column, followed by a limiting amount of antiserum. After incubation, the antibody-bound hormone is separated by a buffer wash. The assay exhibits satisfactory recovery and parallelism, and the intraand inter-assay coefficients of variation are &lt;10%. The values obtained by using the assay correlate well (r = 0.97) with those from a comparison method in which solvent extraction and chromatographic purification are used.