bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improved Colorimetric Method for Assay of Amphetamines in Urine
Authors: Frings Christopher S , Queen Cecelia , Foster Lowell B 
Published: January 2020

Abstract
The increasing abuse of drugs makes it imperative to have rapid, selective methods for their detection. Methods for amphetamines in which methyl orange is used as a reagent are subject to interference by a number of drugs. In the present modified, improved method, amphetamines combine with methyl orange to form a chromogen that follows Beer’s law at 515 nm to amphetamine concentrations of 10 mg/100 ml. Most interfering drugs are removed by pre-extraction into chloroform at pH 5.5. Of over 40 commonly used drugs, including organic bases and alkaloids, only amphetamine, dextroamphetamine, methamphetamine, and pentazocine HCl ("Talwin") react to produce a chromogen in this method. Recovery of amphetamine added to serum and urine is essentially 100%, as compared with aqueous standards taken through the entire procedure. The coefficient of variation is 8.9%. The method described, far more (but not completely) selective for amphetamines than previous methyl orange methods, is rapid, precise, and sensitive, which makes the method valuable in drug abuse screening programs—for which the speed is even greater, because only information on the qualitative presence or absence of amphetamines is required.
Automated Dithionite Test for Rapid, Inexpensive Detection of Hemoglobin S and Non-S Sickling Hemoglobinopathies
Authors: Nalbandian Robert M , Nichols Bruce M , Camp Frank R , Lusher Jeanne M , Conte Nicholas F , Henry Raymond L , Wolf Paul L 
Published: January 2020

Abstract
Automated adaptations of dithionite and urea—dithionite tube tests are accurate, reliable, inexpensive methods for detecting hemoglobin S. More than 3,000 individuals have been screened (120 determinations per hour; reagent cost, 2 to 4 cents per test). The dithionite reagent consists of potassium phosphate, sodium dithionite, and saponin. When S hemoglobin contacts this reagent, the red cells lyse, and the hemoglobin deoxygenates and sickles, forming a hydrophobic-bond-dependent nematic liquid crystal system that is manifested as turbidity. The resulting AutoAnalyzer curve is strikingly and diagnostically different from that produced by hemoglobin A in the same reagent. Specificity of the automated dithionite test may be enhanced by use of the automated urea—dithionite test, which consists of a specimen set of two aliquots: one traverses a dithionite line, the other a urea—dithionite line. A comparison of transmittance in the two lines yields typical diagnostic curves because the urea disperses the sickling, with a consequently increased transmittance over that of the dithionite aliquot. Methods are discussed for recognizing non-S sickling hemoglobins and a few other rare hemoglobinopathies.
A Modification of the "Sickledex" Test for Hemoglobin S
Authors: Powell James B , Beach Douglas J 
Published: January 2020

Abstract
The "Sickledex" test for hemoglobin S has been modified by the use of "Microtiter" plates and microliter sampling equipment. For screening purposes the testing procedure is faster, with significant glassware savings and a 10-fold decrease in sample and reagent requirements. Results are identical to those of the standard Sickledex test.
Automated Simultaneous Turbidimetric Determination of Cholesterol in β- and pre-β-Lipoproteins
Authors: Lopez A , Vial R , Gremillion L , Bell L 
Published: January 2020

Abstract
An automated method is described for simultaneously determining cholesterol in serum β- and pre-β-lipoprotein fractions. This fast, reproducible, accurate method depends on the ability of β- and pre-β-lipoproteins to form insoluble complexes with polyanionic polysaccharides such as heparin. Values obtained by this method and by similar manual methods described in the literature agree well. This method is extremely useful in mass screening for hyperlipidemias; in certain cases it may be more useful than the determination of only cholesterol or triglycerides.
Interaction of Chlorpromazine with Bile
Authors: Clarke A E , Denborough M A 
Published: January 2020

Abstract
Chlorpromazine causes precipitation both of the glycoprotein and protein components of bile in vitro. The reaction depends on an electrostatic interaction between the negatively charged carboxyl groups on the bile components and the positively charged amine groups on the drug molecules in solution. The optimum conditions for the interaction between chlorpromazine and bile components have been established, and the suggestion is made that this precipitation may be responsible in part, for cholestatic jaundice associated with the administration of chlorpromazine.
Routine Gas—Liquid Chromatographic Method for Simultaneous Assay of Major Urinary 17-Ketosteroids, and Pregnanediol and Pregnanetriol
Authors: Holub William R 
Published: January 2020

Abstract
Many methods of urinary steroid analysis have been used in evaluating endocrine function. Individual determination of particular metabolites and functional group analysis of steroid groups frequently involves extensive isolation and correction for interferences. By utilizing the separative and quantitative capabilities of gas-liquid chromatography, we have developed a method for the simultaneous analysis of certain clinically significant urinary steroids. Each analytical step has been made optimal, resulting in a simple and rapid method for determining these steroid metabolites in urine. Although it is a good technique for isolating and concentrating steroid conjugates, ammonium sulfate precipitation of the steroid conjugates is frequently unnecessary. Use of sulfatase and glucuronidase provides the most efficient and "clean" hydrolytic procedure.
Sodium Thymolphthalein Monophosphate: A New Acid Phosphatase Substrate with Greater Specificity for the Prostatic Enzyme in Serum
Authors: Roy A V , Brower Mary E , Hayden Jean E 
Published: January 2020

Abstract
We describe the use of sodium thymolphthalein monophosphate as a substrate for measuring acid phosphatase activity in serum. Thymolphthalein is liberated in the reaction and is conveniently measured by increasing the pH of the medium, which produces a color and also stops the hydrolysis. Optimal conditions for enzymatic activity were defined for use in the final assay system. Purified acid phosphatase isoenzymes from various human tissues and sera from patients with nonprostatic diseases most likely to affect serum acid phosphatase activity were used to show that the new method is more specific for the prostatic enzyme than other commonly used procedures for acid phosphatase. Other advantages include simplicity, good sensitivity over a wide range of activity, high precision, zero-order kinetics to about 200 times the upper limit of normal, easy standardization by a pure standard, and reagent stability.
Evaluation of a Spectrophotometric Method for Determination of Total Fecal Lipid
Authors: Fales Frank W 
Published: January 2020

Abstract
A spectrophotometric method is evaluated for determination of total fecal lipid. Duplicate samples of fecal homogenate, an appropriate standard, and a blank, each in acidic, aqueous alcohol, are extracted with petroleum ether. The extracts are analyzed by the spectrophotometric, acid-dichromate oxidation method. The procedure is much briefer and simpler than current gravimetric and titrimetric methods for fecal fat, and a comparative study suggests that the values obtained are of equal diagnostic value to those obtained by the popular Van de Kamer [J. Biol. Chem. 177, 347 (1949)] method for total fatty acids. Fecal samples from patients with various degrees of steatorrhea gave results having a linear relationship between total lipid and total fatty acid excretion (coefficient of correlation, 0.995; regression formula, total lipid = 1.09 (total fatty acid) + 3.4). The slope of near unity indicates that the increased lipid excretion in steatorrhea is almost wholly accounted for by increased triglyceride and fatty acid excretion and that the unsaponifiable fraction remains relatively constant.
Serum Glutamic—Oxaloacetic Transaminase: Evaluation of a Coupled-Reaction Enzyme Assay by Means of Kinetic Theory
Authors: Russell C D , Cotlove E 
Published: January 2020

Abstract
Rate equations and rate parameters are determined for the coupled-reaction assay for serum glutamic-oxaloacetic transaminase in which malic dehydrogenase is used. These are used to interpret observed curves of absorbance vs. time, to select optimum substrate concentrations, and to estimate nonrandom analytical errors. A simple, systematic, general approach is presented, which can readily be applied to other enzyme assays in which two or more reactions are coupled. It depends for its simplicity on access to an adequate computing facility.
Serum Amylase Activity in Liver Disease
Authors: Bhutta Izharul Hasan , Rahman M Ataur 
Published: January 2020

Abstract
Serum amylase activity was measured in 15 normal persons and in 60 liverdisease patients. Impairment of liver was assessed by serum bilirubin and thymol turbidity values. Most of the patients had serum amylase values that were well below the normal limits. Amylase activities were related to the degree of liver dysfunction, and serum amylase decreased as the bilirubin and turbidity values increased.
Studies on Leukocyte Phosphatases. III. Inhibition of Leukocyte Acid Phosphatase by Zinc
Authors: DeChatelet Lawrence R , Cooper M Robert , McCall Charles E 
Published: January 2020

Abstract
Whereas the activity of leukocyte alkaline phosphatase is stimulated by Zn2+, it inhibits acid phosphatase activity. The degree of inhibition of acid phosphatase depends on the pH of the medium, being greater as the pH approaches neutrality. This inhibition may be at least partially reversed by the addition of amino acids, which suggests that interactions of Zn2+ and amino acids may play an important role in regulating the overall phosphatase activity of the leukocyte.
A Facilitated Fractionation of Stable Urinary Estrogens before Their Automated Fluorometric Assay
Authors: Strickler Herbert S , Petty Judith M , Stanchak Patricia J 
Published: January 2020

Abstract
Urine samples to be assayed for estrone, estradiol-17β, and estriol are processed as usual: hydrolysis, ether extraction, and saponification, as well as partition between toluene and alkali. The samples are purified further, fractionated, and assayed by connecting columns containing Sephadex LH-20 to the sample line of an automated system for fluorometric assay. With this procedure, a sample can be fractionated and assayed every 45 min.
Rapid Fluorometric Assay of Estrogen Conjugates in Pregnancy Urine
Authors: Lee Leonie , Hähnel Roland 
Published: January 2020

Abstract
A rapid assay for estrogen conjugates in pregnancy urine is described. It involves extraction of the estrogen conjugates with Amberlite XAD-2, Kober reaction, and fluorometry of the dichloroethane extract of the reaction mixture.
Application of Fe(II)-5-Pyridyl Benzodiazepin-2-ones to the Determination of Plasma or Serum Glucose
Authors: Klein Bernard , Lucas Lois B 
Published: January 2020

Abstract
A new coupled redox procedure has been developed for the determination of glucose in 4 µl of plasma or serum. The photometric endpoint is formation of the violet-blue Fe2+-5-pyridyl benzodiazepin-2-one chelate, for which the absorbance at 580 nm is linear with glucose concentration from 25 to 300 mg/100 ml. Results obtained by the present technique and those obtained by the o-toluidine method and a glucose oxidase method agree well. The mean recovery of glucose added to plasma is 96.6% (range: 92.1-99.6%).
Rat Carcass Calorie Contents as Estimated from Fat and Nitrogen Analyses, Compared with Ballistic Bomb Calorimeter Data
Authors: Keller G H M , Schouten F J M , Dalderup L M 
Published: January 2020

Abstract
Measurements with the ballistic bomb calorimeter do give results that are in good agreement with the conventional measurements of fat and nitrogen content followed by the appropriate calculations, and are appreciably less time consuming.
A Simple Method for Separate Determination of Delta4- and Delta1,4-Corticosteroids in Urine
Authors: Uete Tetsuo , Shimano Noriko 
Published: January 2020

Abstract
Ethanolic solutions of Δ4- and Δ1,4-3-ketosteroids absorb ultraviolet light most strongly in the region of 240 nm, but, as sulfuric acid is added in increasing concentrations, absorption decreases. With sulfuric acid concentrations greater than 40 ml/100 ml of ethanol, the Δ4-3-ketosteroids show an absorption peak at about 290 nm, giving an isosbestic point in the region of 275 nm. However, Δ1,4-3-ketosteroids develop the absorption maximum at around 260 nm with the isosbestic point in the region of 250 nm. This bathochromic shift in ultraviolet absorption was used to separately determine Δ4- and Δ1,4-corticosteroids in urine. Urine is extracted with chloroform or methylene chloride. The extract is purified by chromatography and dissolved in H2SO4:ethanol(1:1, by volume). Ultraviolet absorption is measured at 220, 260, and 300 nm for Δ1,4-corticosteroids such as prednisolone or prednisone; at 250, 290, and 330 nm for Δ4-corticosteroids. The readings are corrected by Allen’s method [J. Clin. Endocrinol. Metab. 10, 71 (1950)] and the amount of steroid is estimated.
Studies on Leukocyte Phosphatases
Authors: DeChatelet Lawrence R , Volk James V , McCall Charles E , Cooper M Robert 
Published: January 2020

Abstract
The activity of leukocyte alkaline phosphatase is inhibited by a number of amino acids, most notably cysteine and histidine. The mechanism of this inhibition involves chelation of Zn2+ by the amino acids, as indicated by the complete reversal of the inhibition by added Zn2+. The concentrations of amino acids and Zn2+ required to affect the enzyme activity are such that their interaction might represent an in vivo mechanism for the control of leukocyte alkaline phosphatase activity.
Ethanol in Brain, as Assayed by Microfluorometry
Authors: Perez Vernon J , Cicero Theodore J , Bahn Barbara A 
Published: January 2020

Abstract
Gas—liquid chromatography (GLC), the technique most often used to measure ethanol in body fluids, is not practical for determining ethanol in tissues. Previously described fluorometric assays were modified for the enzymatic measurement of ethanol in brain and, for comparison, in blood of rats 1 h after intraperitoneal injection of 2.0 g of ethanol per kg of body weight. Mean ethanol content of brain was 23.43 mmol/kg and of blood, 24.18 mmol/ liter. Accuracy of the method was verified by GLC of the blood samples, which gave a mean ethanol content of 24.29 mmol/liter. No endogenous ethanol was measurable fluorometrically or by GLC in blood or brain samples from control animals injected with physiological saline solution (9 g/liter). Because samples of only 1 µl are required, the procedure is particularly useful when ethanol is to be measured in minute brain samples or when only very small volumes of blood are available.
Paper-Electrophoretic Method for Estimating Urocanic Acid in Urine
Authors: Barbieri Domênico , da Silva Iracema Alencastro , Nicolau José 
Published: January 2020

Abstract
A paper-electrophoretic method is proposed for determining urocanic acid in urine. Formiminoglutamic acid can be simultaneously estimated. Data are given for the urocanic acid content of urine from normal persons after a histidine load.
Ketosis Causing Spurious Elevation of SGOT Values
Authors: Wolf Paul L , Langston Claire , Potolsky Abraham I , Williams Dorothy J 
Published: January 2020

Abstract
In two patients, spurious enhancements of SGOT on SMA 12/60 determination caused erroneous diagnoses of liver disease, which could have led to potentially hazardous diagnostic measures. Such errors can be avoided by an ultraviolet spectroscopic check of suspect SGOT values.
High-Voltage Thin-Layer Electrophoretic Method for Detecting Histidinemia
Authors: Newton Dale A , Summer George K 
Published: January 2020

Abstract
A high-voltage thin-layer electrophoretic method is described for separating urinary histidine and imidazoleacetic, imidazolelactic, and imidazolepyruvic acids. The procedure provides a reliable confirmation of the diagnosis of histidinemia.
Macroamylasemia: Rapid Detection Method
Authors: Fridhandler Louis , Berk J Edward , Ueda Masatoshi 
Published: January 2020

Abstract
A reliable method is presented for rapidly screening human sera to detect macroamylasemia. A mixture of the serum to be tested, Blue Dextran, and cytochrome c is filtered through a small column of cross-linked dextran gel (Sephadex G-100). Amylase in the effluent fractions is detected by incubation with amylose and subsequent addition of iodine. Macroamylase, if present, is found in the blue-colored fractions, while amylase of normal molecular weight appears in the fractions colored by cytochrome c.
Simple Assay for Urinary Estrogens in Nonpregnancy
Authors: Chu T M , Osawa Yoshio , Reynoso Gustavo 
Published: January 2020

Abstract
A simple procedure is described for the selective extraction of urinary estrogens by concentration on XAD-2 resin and elution with ethanol:water (30:70, by vol). Fractionation of estrogens, with high sensitivity and good recovery, from urine of nonpregnant individuals is made possible by combined use of XAD-2 resin extraction and gas—liquid chromatography.
Rapid Method for Protein Quantitation by Electroimmunodiffusion
Authors: Gill Charles W , Fischer Craig L , Holleman Carolinda L 
Published: January 2020

Abstract
In the electroimmunodiffusion method described, a Mylar-backed cellulose acetate membrane plate is used as a support medium. Results are obtained faster, less preparation time is required, and the method is less expensive because less antisera is needed. Results with the method are reproducible (CV, 5%), correlate well with results by the single radial immunodiffusion method, and sensitivity is similar to the electroimmunodiffusion method in which agar gel is used as a support medium.
Method for Quantitative Measurement of Xanthurenic Acid in Urine
Authors: Wallace Mary Jean , Vaillant Henry W , Salhanick Hilton A 
Published: January 2020

Abstract
A method is reported for determining urinary xanthenuric acid (XA), a metabolite of tryptophan. XA is extracted from urine with isobutanol (2-methyl-1-propanol), transferred to ammonium hydroxide, and separated from other urinary metabolites on thin-layer cellulose plates with use of 0.2 acetate buffer, mol/liter, pH 5.4. The XA is measured spectrophotometrically after diazotization with 2-chloro-4-nitroaniline. The method, which is specific for XA, can be used to measure amounts as low as 0.4 µg/ml of urine. It has a range from 0 to 24 µg/ml, and results within this range are reproducible within approximately ±5%. Data obtained by this procedure are comparable to results reported for other methods.
Determination of Tissue Calcium by Nondestructive Neutron Activation Analysis
Authors: Livingston Hugh D 
Published: January 2020

Abstract
A method is described for measuring the concentration of calcium in arterial tissue by neutron activation analysis. The principal advantage is that the method is nondestructive and is ideal for analytical situations in which multiple biochemical measurements are required on a few-milligram sample. Application of the method is illustrated here by a study of aortic calcium metabolism in pigeons and monkeys being used as animal models in experimental atherosclerosis studies. The determination is made on irradiated dry fat-free tissue by using 49Ca (T½, 8.8 min) to measure calcium. The interference of 37S with the measurement is insignificant. Neutron activation data from one set of tissues were compared with data obtained by atomic absorption spectrophotometry in the same tissues. Good relative agreement was found, although results by atomic absorption were slightly systematically higher than those by neutron activation. Reasons for this are discussed.
A Systems Analysis of GEMSAEC Precision Used as a Kinetic Enzyme Analyzer
Authors: Maclin Ernest 
Published: January 2020

Abstract
Use of the GEMSAEC as a kinetic enzyme analyzer has been one of the most promising applications for this instrument. Several important variables must be defined if a practical system and components are to be developed for use in the clinical laboratory. The effect and inter-relationship of four of these are defined and analyzed to determine their impact on the precision of GEMSAEC: starting absorbance of the sample—reagent mixture, rate of change of absorbance, length of time for which the linear kinetic reaction progresses, and the uncertainty of the analog-to-digital conversion combined with electronic noise. A set of curves is generated from equations derived to demonstrate the coefficient of variation based on these variables. The influence of these variables, as compared to the variations of sample and reagent addition and of temperature control, is also briefly reviewed. The performance of the ENI GEMSAEC against these errors is summarized. The techniques described also define a convenient and practical way to evaluate the limits of precision that can be expected from analyzers for kinetic analysis based on the rate of the reaction rather than on a specific chemical determination.
Feasibility of Multiple Simultaneous Enzyme Assays, for Diagnostic Purposes, with the GeMSAEC Fast Analyzer
Authors: Tiffany Thomas O , Johnson George F , Chilcote Max E 
Published: January 2020

Abstract
The GeMSAEC fast analyzer provides the clinical chemistry laboratory with an analytical instrument that can be used to perform large numbers of kinetic enzyme analyses. Precise enzyme-rate analyses can be done routinely, on a large scale, and at a decreased cost per test. Improved precision in analyses of enzymes should provide more reliable data because analytical variation is lessened. We have asked how the fast analyzer might provide more useful diagnostic information to the clinician. We have selected the ratio of SGOT to SGPT activity in serum as an example, and examined instrumental precision. The coefficients of variation of the ratio, determined in the range of 50 and 140 Karmen units (which represents slightly elevated to clearly elevated values), are 4.8% and 2.2%, respectively. We examined the feasibility of measuring two or more enzyme activities simultaneously in one sample, to produce a diagnostic enzyme profile. Determination of SGOT, SGPT, and GLDH in parallel is presented as an example. In addition, we illustrate spectrophotometric linearity at 340 nm and discuss instrumental noise and an experimental approach to determining it by use of a premix experiment.
A Small, Automated High-Resolution Analyzer for Determination of Carbohydrates in Body Fluids
Authors: Katz Sidney , Dinsmore Stanley R , Pitt W Wilson 
Published: January 2020

Abstract
An improved automated, high-resolution anion-exchange analyzer has been developed for detecting and quantifying carbohydrates in body fluids. This new analyzer is more sensitive than the earlier model and much simpler to construct, operate, and maintain. Improved compact components include an electrically heated, folded 0.22-cm-i.d. anion-exchange column, a miniaturized color-development system that does not use a pump, and a miniature flow colorimeter. A large decrease in eluate and reagent flow rates greatly improves the handling of reagents and disposal of waste. Over 50 chromatographic peaks are obtained from 1 ml of urine. The limit of detection for most sugars is between 0.4 and 3.0 µg/ml.