bluuebunny/crossref_metadata_2025 huggingface dataset:
Serum Gamma-Glutamyl Transpeptidase Activity as an Indicator of Disease of Liver, Pancreas, or Bone
Authors: Lum Gifford , Gambino S Raymond
Published: January 2020

Serum γ-glutamyl transpeptidase (GGT), leucine aminopeptidase, alkaline phosphatase, alanine aminotransferase, and aspartate aminotransferase activities were assayed in controls and in patients with liver, pancreatic, or bone disease. GGT activity was above normal in all forms of liver disease studied (viral hepatitis, cirrhosis, cholecystitis, metastatic carcinoma to liver, pancreatic carcinoma, liver granuloma, and acute pancreatitis). GGT more sensitively indicated hepatic disease than did alkaline phosphatase, much more so than did leucine aminopeptidase. GGT was disproportionately more active in relation to the transaminases in cases of intraor extrahepatic biliary obstruction; the reverse was true in cases of viral hepatitis. GGT activity was normal in children, adolescents, and pregnant women, and in cases of bone disease and renal failure. Kinetic measurement of GGT activity offers a simple, sensitive, and direct means for distinguishing whether bone or liver is the source of increased serum alkaline phosphatase activity. Activity was highest in obstructive liver disease.
An L-Aspartate: 2-Oxoglutarate Aminotransferase Reference Material from Human Erythrocytes: Preparation and Characterization
Authors: Rej Robert , Vanderlinde Raymond E , Fasce Charles F
Published: January 2020

L-Aspartate: 2-oxoglutarate aminotransferase (EC 2.6.1.1) from human erythrocytes is purified for use as a reference material in clinical assays for the enzyme. The procedure involves heat treatment in the presence of a substrate (2-oxoglutarate), ammonium sulfate precipitation, and fractionation with n-butanol. The material is further purified by anion- and cation-exchange chromatography. Specific activity obtainable by a typical preparation is 110 µmol min-1 mg-1 at 30°C. Identical behavior is demonstrated between enzyme in human serum and purified erythrocyte enzyme when substrate concentrations, temperature, and pH are varied. A lyophilized preparation at 4°C is stable for longer than 400 days. Data regarding purity and behavior in currently used clinical assays is described.
Carbon Rod Atomizer Applied to Measurement of Lead in Whole Blood by Atomic Absorption Spectrophotometry
Authors: Kubasik N P , Volosin M T , Murray M H
Published: January 2020

An atomic absorption method is described for determining lead in blood by means of the carbon rod atomizer. With the procedure, only a dilution of the whole blood sample is required, and results are comparable to those obtained by the more generally used atomic absorption flame technique. Advantages of the carbon rod include rapid analysis, simple sample preparation, and small sample volumes.
Cellulose Acetate Electrophoresis of Alkaline Phosphatase Isoenzymes in Human Serum and Tissue
Authors: Fritsche H A , Adams-Park H R
Published: January 2020

We describe a new electrophoretic method for the characterization of human serum and tissue alkaline phosphatases on cellulose acetate plates. Enzymes are localized fluorometrically with the substrate α-naphthol AS-MX phosphate or colorimetrically by coupling the reaction product with Fast Blue RR. Both localization techniques are sensitive enough to demonstrate isoenzyme patterns in micro-scale samples of normal sera. Our electrophoretic studies indicate that sera of children and adults normally contain isoenzymes originating from both liver and bone. The high sensitivity of the method allows the use of normal sera as markers rather than tissue extracts, and isoenzyme patterns may be visually assessed after heat inactivation and chemical inhibition. The method is suitable for the electrophoretic fractionation of alkaline phosphatase in large numbers of sera, with equipment and technique familiar to many laboratories.
Coulometric Determination of Activity of Acid or Alkaline Phosphatases in Serum
Authors: Brooks Marvin A , Purdy William C
Published: January 2020

A constant-current coulometric technique is described for measuring acid or alkaline phosphatase activity in serum. Electrogenerated bromine is used as the titrant of phenol enzymatically released from phenyl phosphate. A biamperometric end-point detection system is used, with an applied potential of 135 mV. Titrations are performed at pH 1 with use of a generating electrolyte of 0.5 molar KBr in 0.05 molar H2SO4. A procedure is described for determining serum alkaline phosphatase activity by use of 2-amino-2-methyl-1-propanol (0.25 mol/liter, pH 10.25) with Mg2+ activator (1 mmol/liter), and for determining serum acid phosphatase activity in citrate buffer (0.1 mol/liter, pH 4.9). Results compare favorably with those of the method of Kind and King [J. Clin. Pathol. 7, 322 (1954)].
Ultraviolet Spectrophotometric Measurement of Chlordiazepoxide in Plasma
Authors: Jatlow Peter
Published: January 2020

A simple ultraviolet spectrophotometric method is described for measurement of chlordiazepoxide in blood. The drug is extracted into chloroform at pH 7.4 and, after a NaOH wash, extracted back into HCl. The drug is identified by its characteristic ultraviolet spectra at acidic and basic pH’s, and quantified from the absorbance value measured at the major acid peak of 247 nm. Although certain weakly basic drugs theoretically could interfere if present concurrently with chlordiazepoxide, we have not seen this during three years of experience. This procedure is easily combined with established methods for barbiturates and glutethimide. Specimens from more than 60 cases of documented chlordiazepoxide ingestion have had concentrations ranging from 0.2 to 6.6 mg/100 ml by this procedure.
Low Aspartate Transaminase Activity in Serum of Patients Undergoing Chronic Hemodialysis
Authors: Wolf Paul L , Williams Dorothy , Coplon Norman , Coulson Alan S
Published: January 2020

Glutamic-oxalacetic transaminase (aspartate transaminase) activity is decreased in serum of patients undergoing long-term hemodialysis. The reason may be the repeated dialysis, pyridoxine depletion, or both.
Assay of Human Plasminogen in Plasma by Affinity Chromatography
Authors: Zolton Raymond P , Mertz Edwin T , Russell Henry T
Published: January 2020

A direct, rapid (<3h), and simple technique is described for assaying human plasminogen by affinity chromatography. Plasma is passed over a column of Sepharose—butyl aminobenzoate. The unretarded proteins, including plasmin, are washed out with phosphate—saline, pH 7.4, buffer. The bound plasminogen is released by adding lysine, 0.1 mol/liter, to the buffer and the plasminogen concentration in the eluate is determined by absorbance measurements at 280 nm. A value of 195 ± 10 mg/liter was found for pooled donor plasma from normal individuals. Twenty-one normal women, age 21 to 46, had an average value of 194 ± 38 mg/liter, while 14 pregnant women in the third trimester had an average value of 250 ± 55 mg/liter. The range in 30 hospital patients with various ailments was 122 to 265 mg/liter.
Exploratory Experiments in Direct Evaluation of Renal Metabolic Capabilities
Authors: Lacy Sushil S , King J Stanton
Published: January 2020

In experiments on bloodless maintenance of the kidney during renal surgery, some ancillary observations were made to test the idea that the canine kidney in situ could satisfactorily be so used to study renal metabolism. Results of these tentative biochemical experiments are reported here in the hope that others will be encouraged to continue them.
Detection of Interrupted Bubble Flow in the Technicon Automated Immunoprecipitin System
Authors: Hansen Robert J , Tschida Anthony R , Markowitz Harold
Published: January 2020

A simple unit is described for detecting interrupted flow in an automated immunoprecipitin system. The principle involved is conductivity change resulting from interruption of bubble flow.
Dynamic Introduction of Whole-Blood Samples into Fast Analyzers
Authors: Scott Charles D , Mailen James C
Published: January 2020

A new automated method of sample preparation and introduction that may circumvent the problems of measurement of micro-scale quantities of samples and preparation of serum or soluble blood fraction is being developed for use in fast analytical systems based on the GeMSAEC principle. This method involves the dynamic introduction of reagents or blood samples into the centrifugal field of the Fast Analyzer during rotation of the rotor. The rotor can be designed to fractionate the fluid into discrete, measured portions that are transferred to the cuvets for photometric monitoring. Whole-blood samples can be directly introduced into the rotating rotor where, after fractionation into measured volumes, the particulates are automatically removed by the centrifugal field and the resulting measured quantities of plasma are transferred directly to the cuvets. The dynamic proportionation of reagents, serum, and whole blood has been shown to be precise, and automatic analyses for specific chemicals have been performed on whole blood samples with a coefficient of variation of less than 2%.
Simultaneous Multicolumn Operation of the UV-Analyzer for Body Fluids
Authors: Pitt W Wilson , Scott Charles D , Jones Guy
Published: January 2020

At the current state of development, high-resolution liquid chromatographs for analyses of complex physiologic fluids require relatively long analysis times and consequently the rate at which analyses can be done is limited. This rate can be increased by decreasing the analysis time or by use of multiple columns to process several samples in unison. An automated multicolumn high-resolution chromatograph for separating ultraviolet-absorbing molecular constituents of body fluids is being developed. The sample-handling capacity was increased several-fold with minimum added cost by using many of the components of the single-column analyzer. Results from routine use of a UV-Analyzer with two columns in parallel show that parallel operation is not only feasible but highly advantageous. The design of a high-pressure, multiple-column, sample injection valve for simultaneous injection of samples on different columns is discussed.
Enzymatic Kinetic Rate and End-Point Analyses of Substrate, by Use of a GeMSAEC Fast Analyzer
Authors: Tiffany T O , Jansen J M , Burtis C A , Overton J B , Scott C D
Published: January 2020

Enzymatic substrate analysis is an attractive means of analysis in clinical chemistry because of its sensitivity and specificity. The GeMSAEC Fast Analyzer, in conjunction with a small computer, provides a means of performing routine enzymatic substrate analysis and offers the following advantages: (a) selectivity of approaches to enzymatic analysis, i.e., end-point or kinetic; (b) essentially parallel analyses of multiple samples, yielding a unique method for performing kinetic fixed-time analysis; (c) on-line data reduction, resulting in rapid calculation and output of results and the minimization of data handling errors; and (d) a small reagent volume per test (400 µl), which reduces the cost of analysis. The analysis of substrate with enzymatic end-point and kinetic procedures is examined by use of a computer-interfaced Fast Analyzer. Computer programs were written to facilitate this study. Glucose (hexokinase/GPD), urea (urease/GMD), and uric acid (uricase) have been used as examples in evaluating both end-point and kinetic analyses. The advantages and limitations of each type of analysis are presented, with the emphasis being placed on enzymatic substrate analysis and means by which the computer-interfaced Fast Analyzer can facilitate both end-point and kinetic analyses.
Factors Affecting the Results of Serum Cholesterol Determinations: An Interlaboratory Evaluation
Authors: Fasce Charles F , Vanderlinde Raymond E
Published: January 2020

We present results of an interlaboratory survey of cholesterol assays in which methodology, standardization technique, type of standard, reagent source, and control sera used are considered. Each of these factors is evaluated, on both clear and icteric sera, with respect to accuracy, interlaboratory precision, and associated random error. We find that most participants use direct techniques, that these laboratories do not use correction procedures where these are needed, and that not all extractants effectively prevent bilirubin interference. Our data illustrate that precision on clear sera is best by direct procedures, but not in the presence of bilirubin. Participants uniformly exhibit better intralaboratory precision than interlaboratory agreement, regardless of the variable being studied. It is appropriate to consider the interactions of variables if a technique is to be properly evaluated.
Determination of Glucose in Serum and Whole Blood: Statistical Relationships between Values Obtained by Different Methods
Authors: Geeting David G , Suther Charles A , Sylbert Philip
Published: January 2020

Several methods are available for determination of glucose in whole blood and serum. When comparing the results of these methods on a single blood sample, one may find significantly different values. Here, equations are provided for converting values for whole blood glucose to values for serum glucose, obtained by different methods.
A Discussion of Enzyme Reference Materials: Applications and Specifications
Authors: Fasce Charles F , Rej Robert , Copeland William H , Vanderlinde Raymond E
Published: January 2020

Clinical laboratories estimating enzyme activity in serum are using commercial lyophilized sera for four major purposes. These uses—as a standard and for intermethod, intramethod, and precision control—are segregated, and specifications for each deployment are examined in terms of requirements for the enzyme material: freedom from interfering or indicator enzymes and chromogens; high specific activity; inclusion of optimal cofactor concentrations; commutability, human properties and source; the presence of a single isoenzyme; and stability. The effects of serum matrix and variable assay conditions on the utility of enzyme materials are analyzed. Specifications differ for each enzyme material application. The compatibility of commercial lyophilized sera containing aspartate aminotransferase activity with several cited specifications is assessed
Determination of Lead in Blood and Urine by Anodic Stripping Voltammetry
Authors: Searle Bernard , Chan Wing , Davidow Bernard
Published: January 2020

An anodic stripping procedure for determining lead in blood and urine was evaluated, and methods of calibration were developed. The technique requires as little as 50 µl of blood or 0.5 ml of urine. Comparisons were made between results obtained by anodic stripping voltammetry, for finger-puncture blood, and by atomic absorption spectrophotometry, for venous blood from 200 children. The two methods were also compared with respect to lead in urines from patients hospitalized for suspected lead poisoning and in urines from normal healthy volunteers. Major advantages of the anodic stripping method are its increased sensitivity and lower cost as compared to many current methods for detecting and measuring lead
Estimating Correlations from Single-Sample Distributions of Measurements
Authors: Harris Eugene K
Published: January 2020

The correlation coefficient between two variables (e.g., blood constituents) in normal individuals (or in patients) is usually estimated from measurements of both variables in single samples from the individuals studied. This coefficient is supposed to represent a correlation between the two variables within the average individual. However, unless all the subjects have identical mean values, the "single-sample" coefficient also reflects the correlation of mean values across individuals, generally different from the average intra-individual correlation. Even when both intra-and interindividual correlations are equal, the "single-sample" coefficient underestimates the true intra-individual correlation unless corrected for measurement errors. Using data from normal individuals, two examples are presented: in one case (calcium-total protein), the corrected single-sample coefficient appears to be an unbiased estimate of the desired correlation, whereas in the other example (albumin-globulins), it is quite misleading. These examples support the need for multiple, independent samples from each individual to assure a valid estimate of the average intra-individual correlation between two variables
Radioassay of Serum Folate
Authors: Dunn Ralph T , Foster Lowell B
Published: January 2020

We describe a radioassay procedure for serum folate, in which commercially available crystalline β-lactoglobulin is used as the folate-binding agent. The folate binders present in serum are eliminated by heating serum in a boiling water bath for 15 min to denature the proteins. Radioassayable serum folate is shown to be stable under these conditions, and the results for folate compare well with those obtained by a microbiological assay.
Automated Glucose Methods: Evaluation of a Glucose Oxidase—Peroxidase Procedure
Authors: Romano Anna T
Published: January 2020

We have evaluated methods in which glucose oxidase is used to determine serum glucose with the "AutoAnalyzer-II" and "SMA 12/60" (Technicon). A glucose oxidase—peroxidase—dianisidine procedure with improved specificity developed during this study is described. The glucose value is unaffected by the presence of 16 mg of uric acid per deciliter, and the system is highly resistant to interference from many other reducing compounds added to serum. The method appears to give "true glucose" values for normal, hyperuricemic, and uremic subjects. Results are compared with those from the "GOD-Perid," glucose oxidase—peroxidase—MBTH—DMA, hexokinase, toluidine, ferricyanide, and SMA 12/60 neocuproine techniques, as well as with those from our index of "true glucose," a procedure based on measurement of reducing material before and after treatment with glucose oxidase. Specificity and performance of the glucose oxidase—peroxidase—dianisidine and glucose oxidase—peroxidase—MBTH—DMA procedures are similar.
Comparison of Glutethimide Concentration in the Serum and Cerebrospinal Fluid of Humans in Drug Overdose
Authors: Gold Martin , Tassoni Ernest , Etzl Michael
Published: January 2020

Glutethimide concentrations were measured gas chromatographically in the serum and cerebrospinal fluid (CSF) of patients in coma caused by overdose of this drug. Piperidione was used as an internal standard. In the first serum samples collected from each patient, the glutethimide concentration ranged from 0.9 to 3.1 mg/dl. No patient had a CSF glutethimide concentration of more than 0.8 mg/dl. If one excludes patients who regained consciousness in less than 7 h, the seven remaining cases may be described by the following equation: y = 16.06 x1.06 where y = duration of coma (in h) and x = maximum serum glutethimide concentration (in mg/dl). The correlation coefficient for this equation was 0.911.
Rapid Determination of Ammonia in a Perchloric Acid Supernate from Blood, by Use of an Ammonia-Specific Electrode
Authors: Proelss Henning F , Wright Billy W
Published: January 2020

A simple, rapid method was developed for accurate determination of ammonia in whole blood. Blood proteins were precipitated with perchloric acid (8 g/dl) and the free ammonia liberated in the supernate on alkalinization was measured directly with an ammonia-specific electrode after adjusting the sample temperature to 25 °C. Some variables affecting precision, accuracy, and electrode performance were studied. Sensitivity, specificity, and interferences are discussed. The tentative normal range is 28 ± 14 µg of ammonia nitrogen per deciliter. The coefficient of variation was 4.8% in the "normal," 3.6% in the "abnormal" range. Abnormal values were correlated with clinical status. Recoveries averaged 99.3%. Correlation with an established ion-exchange method for plasma ammonia was 0.994. Total time required for a complete assay is 15 min.
Comparison of Four Methods for Measuring Uric Acid: Copper-Chelate, Phosphotungstate, Manual Uricase, and Automated Kinetic Uricase
Authors: Lum Gifford , Gambino S Raymond
Published: January 2020

Glutathione, ascorbic acid and many commonly used antibiotics falsely elevate uric acid concentrations when measured with the Du Pont "aca," in which the copper-chelate method is used. L-Dopa interferes with both the copper-chelate method and the Technicon "SMA 12/60" phosphotungstate method. A new kinetic uricase method has been developed for use on the Du Pont aca. This kinetic uricase method has a coefficient of variation of 2.40% and gives values that are essentially identical to those obtained by a manual end-point uricase method.
Phase Equilibrium of Oxygen in "Nitrogen-Filled Vacutainers"
Authors: Mueller Rudolph G , Lang Gordon E
Published: January 2020

Relationships describing the exchange of oxygen between the liquid and gas phases in a "Vacutainer" are derived and substantiated. The use of Vacutainers for determining P(O2) and percent oxyhemoglobin saturation is condemned.
Magnesium Gluconate as a Standard for the Determination of Serum Magnesium
Authors: Zief M , Barnard A J , Rains T C
Published: January 2020

Magnesium gluconate is shown to be a potential Standard Reference Material for magnesium determination.
Modified Automated Saccharogenic Determination of Serum and Urinary Amylase Activity
Authors: Matthews W S , Sterling R E , Boyd T , Flores O R
Published: January 2020

The automated method of O’Neal and Gochman [Clin. Chem. 16, 985 (1970)] for determination of serum and urine amylase activity has been modified to increase its accuracy, precision, and efficiency. Sampling rate is 50 specimens per hour. The analysis depends on α-amylase hydrolyzing glycogen to maltose-like subunits, which are measured with the copper neocuproine reaction. Results obtained by this method are compared to those for a manual reference method [Clin. Chem. 6, 434 (1960)].
Critical Variables in the Radioimmunological Technique for Measuring Immunoreactive Insulin with Use of Immunosorbents
Authors: Velasco Carlos A , Oppermann Werner , Camerini-Davalos Rafael A
Published: January 2020

A commercial kit for determining immunoreactive insulin, the "Phadebas Insulin Test," was methodically evaluated to establish the optimal conditions for this immunoassay. Sensitivity, day-to-day and within-run precision, recovery, accuracy, and specificity are excellent. Results by this method compare favorably with those of the double-antibody technique. This rapid, simple, convenient, and reliable procedure for insulin immunoassay can be easily adapted to the facilities of a clinical laboratory as a standard diagnostic test or for clinical reseach.
Method for Determination of Cyclic AMP in Plasma
Authors: Rabinowitz Babeth , Katz Joseph
Published: January 2020

A simple procedure is described for measuring cyclic AMP (cAMP) in plasma, body fluids, and tissue extracts. A modification of the method of Brown et al. [Biochem. J. 121, 561 (1971)], it is based on competitive binding of cAMP by a protein in crude adrenal extracts, and precipitation of the cAMP-protein complex by ammonium sulfate. cAMP concentrations in normal human plasma ranged from 8 to 16 nmol/liter, and in the plasma of dogs from 5 to 15 nmol/liter. The range of the method is 0.5-8 pmol per assay, and up to 0.4 ml of sample can be used. A cheap and easily prepared binding-protein is used and the procedure is suitable for clinical studies of cAMP concentrations in plasma.
Evaluation of the Delves Micro System for Blood Lead Analysis
Authors: Hicks Jocelyn M , Gutierrez Aida N , Worthy Brenda E
Published: January 2020

Correlation between results of a conventional macroscale (5 ml of blood) atomic absorption procedure for lead determination and results of the Delves micro-scale (10 µl blood) atomic absorption method was high (0.96). Analyses of lead in capillary and intravenous blood samples also correlated well (0.93). The coefficient of variation of the Delves micro-scale method was 8% for a concentration of 46 µg of lead per milliliter. We conclude that the Delves microscale method—which is simpler, requires smaller samples than previous methods, and can be readily applied to capillary. ("finger-stick") blood—is very suitable for a pediatric practice and for the screening of large numbers of patients.
Automated Fluorometric Determination of Amphetaminein Urine
Authors: Hayes T S
Published: January 2020

A completely automated fluorometric determination of amphetamine in urine is described and evaluated. The dihydrolutidine derivative produced by reaction of amphetamine with formaldehyde and acetylacetone is excited at 410 nm and the resulting intensity of fluorescence measured at 476 nm. The working limit of detection of amphetamine in fresh urine (1.5-ml samples) is 0.15 mg/liter. A result is produced for the first sample in about 20 min; subsequent results are obtained at 2-min intervals. Falsely positive reactions are given by 2-phenylethylamine and tuaminoheptane.
Comparison of the Stannous Chloride and Vanadate Methods for Estimation of Serum Inorganic Phosphorus by Use of the "SMA 12/60"
Authors: Davies Janet L , Andrews G S , Miller R , Owen H G
Published: January 2020

We compared results of the stannous chloride and vanadate methods for estimating serum inorganic phosphorus on the "SMA 12/60" (Technicon). The technically simpler vanadate method gave better linearity and reproducibility, with virtually no carry-over or baseline drift; the reagents were stable, and it was most important to ensure that the concentration of sulfuric acid in the recipient and sample streams was identical. Instability in the stannous chloride method was due to precipitation in the stannous chloride-hydrazine working solution.
Rapid Method for Screening for Galactosemia and Galactokinase Deficiency by Measuring Galactose in Whole Blood Spotted on Paper
Authors: Grenier André , Laberge Claude
Published: January 2020

An inexpensive automated fluorometric technique for blood galactose determination has been modified to use dried blood spots available through phenylketonuria screening programs. The method is more efficient because of its high capacity (≃85,000 tests a year), low cost (≃$3,000 a year in reagents), and high specificity (enzymatic method).
Rapid Method for Quantitative Determination of Propoxyphene in Serum by Gas-Liquid Chromatography
Authors: Evenson M A , Koellner Susan
Published: January 2020

Rapid, accurate, and precise gas-chromatographic methods are reported for measurement of propoxyphene ("Darvon") in serum. A sample of 5 ml of serum is required for quantitation in blood after a therapeutic dose of 130-195 mg of propoxyphene; in cases of overdose of propoxyphene, only 1 ml of serum is required in a "toxic method" variation. Neither serum from healthy controls or from hospitalized patients contains interfering substances. Several commonly used analgesic and sedative drugs, added to a serum pool, also did not interfere. Day-to-day precision of the therapeutic method, as measured by the coefficient of variation (CV), is 7%; the CV for the method as applied to overdose cases is less than 3%. Propoxyphene added to serum could be about 86% accounted for analytically.
Determination of Uric Acid in Serum, with Use of Uricase and a Tribromophenol—Aminoantipyrine Chromogen
Authors: Kabasakalian Peter , Kalliney Sami , Westcott Anita
Published: January 2020

A manual method is described for determining the hydrogen peroxide produced from uric acid with uricase (pH 9.2) after deproteinization of 1.00 ml of serum. In the method, 2,4,6-tribromophenol is coupled with 4-aminoantipyrine (pH 7.0) by peroxidase oxidative coupling. The sensitivity of the method is such that 25 µg of uric acid from a fourth of the deproteinized serum (100 mg/liter) in a final volume of 5 ml of n-butyl acetate color extract gives a stable absorbance of 0.7 at 492 nm with a 1-cm cell. The method is reproducible, and many substances that may be encountered in serum do not interfere. Absorbances are linear for uric acid concentrations as high as 200 mg/liter.
Formaldehyde Interference in the Uric Acid—Phosphotungstic Acid Redox
Authors: Klein Bernard , Sheehan Joan
Published: January 2020

Formaldehyde, in quantities used to preserve uric acid standard solutions, will introduce errors in the automated analysis of serum uric acid by the Technicon N-13b phosphotungstate procedure, by retarding the dialysis rate. It will also diminish recovery of uric acid when these solutions are added to serum. The mechanism of interference is complex and may involve alteration of dialysis rates, formaldehyde— protein—uric acid interaction, and possibly a competing redox with phosphotungstic acid.
Methaqualone1 Overdose: Analytical Methodology, and the Significance of Serum Drug Concentrations
Authors: Bailey David N , Jatlow Peter I
Published: January 2020

Methaqualone abuse and overdose have recently become "epidemic." We determined concentrations of the drug in serum in 15 cases of overdose by gas— liquid chromatography (GLC) and ultraviolet spectraphotometry (UV). Values by GLC were consistently lower than those determined by UV after chloroform extraction, but correlated well with those obtained by UV after hexane extraction. Our studies show that at least one chloroform extractable metabolite has a spectrum very similar to that of the parent drug. This may in part explain the lower results obtained by GLC and suggests that other reported data based on UV analysis of chloroform and ether extracts may be too high. Extraction with hexane, a less polar solvent, followed by back extraction into HCl provides an accurate UV method suitable for emergency use. Concentration of unchanged methaqualone in serum after overdose ranged from 2 mg/liter to 22 mg/liter in this series; those greater than 8 mg/liter were usually associated with unconsciousness.
Evaluation of EDTA as the Chelator in the Biuret Reagent
Authors: Van Kley Harold , Claywell Carol S
Published: January 2020

Use of ethylenediaminetetraacetate (EDTA) as the chelating agent in the biuret reaction (in place of tartrate or citrate) was investigated. We found that this suggested modification of the reagent results in lower color yields and prolongs the time for color development. The EDTA reagent is more stable if color development is hastened by heating, but conditions are described under which the more customary reagent may be so used.
Variability of Standard Curves in Radioimmunoassay of Plasma Digoxin
Authors: Burnett George H , Conklin Robert L , Wasson Gertrude W , MacKinney Archie A
Published: January 2020

Evaluation of commercial kits (3H and 125I digoxin) for the radioimmunoassay of digoxin showed that different normal plasma samples yielded significantly different standard assay curves. Such differences accounted for errors of from 0.6 to 1 ng under certain conditions. The usual internal assay controls do not correct for these conditions. Because such changes may represent the differences between toxic and nontoxic digoxin concentrations, further study of the commercial test procedures appears to be indicated.
Simultaneous Competitive Protein Binding Assay for Cortisol, Cortisone, and Prednisolone in Plasma, and Its Clinical Application
Authors: Turner Adrian K , Carroll Carthage J , Pinkus Jack L , Charles David , Chattoraj Sati C
Published: January 2020

Simultaneous measurement of cortisol, cortisone, and prednisolone is described. A dichloromethane extract of plasma is separated and purified by partition thin-layer chromatography and assayed by competitive protein binding. Using 0.2 ml of plasma, we could assay about 1 µg of these three steroids per 100 ml. We measured plasma corticosteroids in men on prednisone therapy, during ACTH stimulation, and in pregnant women at the time of delivery, and also in arterial and venous blood samples collected from the umbilical cord. Plasma concentrations of prednisolone (4.46 ± 1.07 µg/100 ml) were maximal 2 h after oral administration of prednisone (10 mg). Basal concentrations of cortisol and cortisone in these subjects were 10.50 ± 1.04 and 1.88 ± 0.69 (SD) µg/100 ml, respectively. The values decreased to less than 1 µg/100 ml 4 h after administration and returned to 12.82 ± 1.92 and 2.16 ± 0.49 µg/100 ml, respectively, by 24 h. After intramuscular injection of synthetic ACTH, values for cortisol and cortisone were maximal at 30 min, declining to pre-injection concentrations within 4 h. Plasma cortisol and cortisone values for maternal venous blood at delivery were 47.0 ± 8.5 and 7.1 ± 2.2, umbilical vein blood 4.9 ± 2.6 and 19.7 ± 2.8 and in blood from the umbilical arteries 7.3 ± 4.5 and 11.6 ± 4.9 µg/ 100 ml, respectively. Cortisol was higher (P < 0.05) in the umbilical arteries, cortisone (P < 0.01) in the umbilical vein.
Improved Techniques for Assessment of Plasma Lipoprotein Patterns. I. Precipitation in Gels after Electrophoresis with Polyanionic Compounds
Authors: Seidel Dietrich , Wieland Heinrich , Ruppert Claudia
Published: January 2020

A method is described for making lipoprotein fractions visible by polyanion precipitation in situ in the gels after electrophoresis. With the new technique the pattern and its interpretation in the differential diagnosis of all primary forms of hyperlipoproteinemia is the same as for the other lipid-staining procedures. The new technique is simpler to perform, reliable, and provides the required information 60 min after electrophoresis. It also allows a very fast determination of the abnormal lipoprotein (LP-X) that characterizes cholestasis, without use of a specific antiserum.
Kinetic Colorimetric Measurement of Serum Lactate Dehydrogenase Activity
Authors: Babson Arthur L , Babson Susan R
Published: January 2020

A kinetic colorimetric assay procedure is described for measuring lactate dehydrogenase activity, in which the reduction of NAD is coupled to the reduction of a tetrazolium salt, 2-p-iodophenyl-3-p-nitrophenyl-5-phenyl tetrazolium chloride (INT), with phenazine methosulfate serving as an intermediate electron carrier. The molar absorptivity of the formazan of INT was found to be 19.3 x 103 at 503 nm, which provides a threefold increase in sensitivity over the ultraviolet (340 nm) kinetic assay. The results correlate well with those obtained by 340-nm kinetic methods and the procedure does not require an ultraviolet spectrophotometer. The method is simple, rapid, and does not rely on secondary enzyme standards. It requires only two reagents, which are stable.
Computer Technique for Identification of Chromatographic Peaks
Authors: Chilcote D D
Published: January 2020

A computer program has been developed to identify known peaks in a chromatogram from a computer-interfaced chromatograph. The focal point of the program is a normalization technique, which refers the elution volume of each sample peak encountered to the elution volumes of two reference peaks that bracket the peak of interest, as is done in certain gas chromatographic normalization techniques. The normalized elution volume is determined by dividing the difference between the elution volumes of the sample peak and the first (early-eluting) reference peak by the difference between the elution volumes of the two reference peaks. The normalized elution volumes thus obtained are compared to normalized elution volumes of known compounds stored in bulk memory. The compounds now being used as reference peaks in the chromatograms from the UV-Analyzer are hypoxanthine, uric acid, hippuric acid, and p-cresol.
Relationship between Variables in Instrument Performance and Results of Kinetic Enzyme Assays—A System View
Authors: Maclin Ernest , Rohlfing Donald , Ansour Manoug
Published: January 2020

Much effort has been expended to define individual instrumental variables and chemical requirements for kinetic assays. In this paper, these variables are grouped together to demonstrate the relationship between characteristics of the instrument system and final results for kinetic enzyme analyses. Tolerances on instrumental variables are reviewed in terms of these final results, and summarized and interpreted as they effect the results of kinetic assays. We have evaluated the effects on absorbance change as they are related to tolerances for absorbance, time, sample volume, reagent volume, temperature, and path-length. Specifications of spectrophotometric instruments in terms of linearity, accuracy, wavelength adjustability and accuracy, stray light, noise, and drift are also reviewed as to their effects on absorbance change. Generalized data are presented and are then related, as an example, to measurement of aspartate aminotransferase activity.
Design, Construction, and Two Applications for an Automated Flow—Cell Polarization Fluorometer with Digital Read Out: Enzyme-Inhibitor (Antitrypsin) Assay and Antigen—Antibody (Insulin—Insulin Antiserum) Assay
Authors: Spencer Richard D , Toledo Fernando B , Williams Ben T , Yoss Norma L
Published: January 2020

We have constructed and automated a flow cell polarization fluorometer and demonstrated two specific clinical applications of fluorescence polarization assay, i.e., the enzyme-inhibitor assay of antitrypsin in serum and the antigen-antibody assay of insulin and its antibody. A signal is displayed directly and is immediately available for chart recording and (or) digital data processing. Since fluorescence polarization offers a number of choices in assay parameters and the use of different fluorescent probes, its development for rapid simultaneous measurements of multiple components in body fluids should be possible.
Evaluation of Kinetic Enzyme Parameters by Use of a Small Computer Interfaced "Fast Analyzer"—An Addition to Automated Clinical Enzymology
Authors: Tiffany T O , Chilcote D D , Burtis C A
Published: January 2020

The evaluation of steady-state enzyme kinetic parameters such as Km, Vmax, and Ki is useful in clinical enzymology, particularly where they can be used for the detection of enzyme variants and to assess the type of isoenzymes and the extent of their abnormal activity. The multiple-cuvet parallel-analysis feature of the Fast Analyzer permits one to evaluate one or more enzymic parameters in a single rotor. Both on-line measurement of initial reaction velocities and rapid off-line reduction of statistical data can be obtained by using the small-computer interfaced Fast Analyzer. Estimates of error in determining these parameters are also obtained, for use in comparing results in future analyses. We discuss the programming approach for adapting both simple and more complex statistical nonlinear regression data-fitting routines to the Fast Analyzer’s computer. We illustrate how the analyzer may be used to determine simple kinetic parameters for placental alkaline phosphatase and glucose-6-phosphate dehydrogenase and for the more complex "stripping out" of Km’s and Vmax’s for a heterogenous mixture of placental and intestinal alkaline phosphatase.
Simplified Gas Chromatography of Trimethylsilyl Esters of C1 through C5 Fatty Acids in Serum and Urine
Authors: Mamer O A , Gibbs B F
Published: January 2020

All the metabolically important C1 through C5 fatty acids and lactic, pyruvic and β-hydroxybutyric acids can be gas chromatographed surprisingly well on the common 2-meter 3% methylphenylsilicone (e.g., "OV-17") column when a late-eluting silylating reagent such as trimethylsilylimidazole is used. In these circumstances, the trimethylsilyl esters elute in an interval that is free of the reagent and solvent interferences usually found when the more volatile preparations are used for silylations. Use of the method is demonstrated by its application to a serum from a case of isovaleric acidemia and a urine from a case of methylmalonic aciduria.
A Simplified Determination of Urinary Cadmium, Lead, and Thallium, with Use of Carbon Rod Atomization and Atomic Absorption Spectrophotometry
Authors: Kubasik Norman P , Volosin Michael T
Published: January 2020

Lead, cadmium, and thallium are determined in a single 3-ml urine sample. The three metals, simultaneously chelated with sodium diethyldithiocarbamate, are extracted (at pH 3-7) into methyl isobutyl ketone (isopropylacetone), and the carbon rod atomizer, in conjunction with atomic absorption spectrophotometry, is used to analyze the extracts. Small sample requirements (1.6 µl) permit the extraction to be carried out in small-volume disposable glassware, with use of disposable pipets. Within-run coefficients of variation were all less than 5%; recovery ranged from 96-106%. Several normal urinary constituents, added in excess, negligibly affected recoveries. Ethylenediaminetetraacetate in the urine inhibited recovery of lead; this was reversed by adding excess calcium to the urine before extraction. The method of standard additions was used to compensate for differences between standards and unknowns caused by matrix effects.
On the General Construction of Tightly Secure Identity-Based Signature Schemes
Authors: Wu Ge , Zhao Zhen , Guo Fuchun , Susilo Willy , Zhang Futai
Published: January 2020

A tightly secure scheme has a reduction, where the reduction loss is a small constant. Identity-based signature (IBS) is an important cryptographic primitive, and tightly secure IBS schemes enjoy the advantage that the security parameter can be optimal to achieve a certain security level. General constructions of IBS schemes (Bellare, M., Namprempre, C., and Neven, G. (2004) Security Proofs for Identity-Based Identification and Signature Schemes. In Proc. EUROCRYPT 2004, May 2–6, pp. 268–286. Springer, Berlin, Interlaken, Switzerland; Galindo, D., Herranz, J., and Kiltz, E. (2006) On the Generic Construction of Identity-Based Signatures With Additional Properties. In Proceedings of ASIACRYPT 2006, December 3–7, pp. 178–193. Springer, Berlin, Shanghai, China) and their security have been extensively studied. However, the security is not tight and how to generally construct a tightly secure IBS scheme remains unknown. In this paper, we concentrate on the general constructions of IBS schemes. We first take an insight into previous constructions and analyze the reason why it cannot achieve tight security. To further study possible tightly secure constructions, we propose another general construction, which could be seen as a different framework of IBS schemes. Our construction requires two traditional signature schemes, whereas the construction by Bellare et al. uses one scheme in a two-round iteration. There are no additional operations in our general construction. Its main advantage is providing the possibility of achieving tight security for IBS schemes in the random oracle model. Combining two known signature schemes, we present an efficient IBS scheme with tight security as an example.
A combined RNA-seq and whole genome sequencing approach for identification of non-coding pathogenic variants in single families
Authors: Bronstein Revital , Capowski Elizabeth E , Mehrotra Sudeep , Jansen Alex D , Navarro-Gomez Daniel , Maher Mathew , Place Emily , Sangermano Riccardo , Bujakowska Kinga M , Gamm David M , Pierce Eric A
Published: January 2020

Inherited retinal degenerations (IRDs) are at the focus of current genetic therapeutic advancements. For a genetic treatment such as gene therapy to be successful, an accurate genetic diagnostic is required. Genetic diagnostics relies on the assessment of the probability that a given DNA variant is pathogenic. Non-coding variants present a unique challenge for such assessments as compared to coding variants. For one, non-coding variants are present at much higher number in the genome than coding variants. In addition, our understanding of the rules that govern the non-coding regions of the genome is less complete than our understanding of the coding regions. Methods that allow for both the identification of candidate non-coding pathogenic variants and their functional validation may help overcome these caveats allowing for a greater number of patients to benefit from advancements in genetic therapeutics. We present here an unbiased approach combining whole genome sequencing (WGS) with patient-induced pluripotent stem cell (iPSC)-derived retinal organoids (ROs) transcriptome analysis. With this approach, we identified and functionally validated a novel pathogenic non-coding variant in a small family with a previously unresolved genetic diagnosis.
Civil society perspectives on sexual violence in conflict: patriarchy and war strategy in Colombia
Authors: Kreft Anne-Kathrin
Published: January 2020

In international policy circles, conflict-related sexual violence (CRSV) is commonly viewed as a weapon of war, a framing that researchers have criticized as overly simplistic. Feminist scholars in particular caution that the ‘weapon of war’ framing decontextualizes sexual violence in conflict from the structural factors of gender inequality that underpin its perpetration. In light of these tensions, how do politically relevant local actors perceive the nature and the origins of conflict-related sexual violence? Civil society organizations often actively confront conflict-related sexual violence on the ground. A better understanding of how their perceptions of this violence align or clash with the globally dominant ‘weapon of war’ narratives therefore has important policy implications. Interviews with representatives of Colombian women's organizations and victims' associations reveal that these civil society activists predominantly view conflict-related sexual violence as the result of patriarchal structures. The mobilized women perceive sexual violence as a very gendered violence that exists on a continuum extending through peace, the everyday and war, and which the presence of arms exacerbates. Strategic sexual violence, too, is understood to ultimately have its basis in patriarchal structures. The findings expose a disconnect between the globally dominant ‘weapon of war’ understanding that is decontextualized from structural factors and a local approach to CRSV that establishes clear linkages to societal gender inequality.
Dairy, soy, and risk of breast cancer: those confounded milks
Authors: Fraser Gary E , Jaceldo-Siegl Karen , Orlich Michael , Mashchak Andrew , Sirirat Rawiwan , Knutsen Synnove
Published: January 2020

Background

Associations between soy, dairy intakes and breast cancer risk are inconsistent. No studies exist with large numbers of dairy consumers and soy consumers to assess mutual confounding.

Methods

The study cohort contains 52 795 North American women, initially free of cancer, followed for 7.9 years (29.7% were Black). Dietary intakes were estimated from food frequency questionnaires and, for 1011 calibration study subjects, from six structured 24-h dietary recalls. Incident invasive breast cancers were detected mainly by matching with cancer registries. Analyses used multivariable proportional hazards regression.

Results

The participants (mean age of 57.1 years) experienced 1057 new breast cancer cases during follow-up. No clear associations were found between soy products and breast cancer, independently of dairy. However, higher intakes of dairy calories and dairy milk were associated with hazard ratios (HRs) of 1.22 [95% confidence interval (CI): 1.05–1.40] and 1.50 (95% CI 1.22–1.84), respectively, comparing 90th to 10th percentiles of intakes. Full fat and reduced fat milks produced similar results. No important associations were noted with cheese and yogurt. Substituting median intakes of dairy milk users by those of soy milk consumers was associated with HR of 0.68 (95% CI: 0.55–0.85). Similar-sized associations were found among pre- and post-menopausal cases, with CIs also excluding the null in estrogen receptor (ER+, ER-), and progesterone receptor (PR+) cancers. Less biased calibrated measurement-error adjusted regressions demonstrated yet stronger, but less precise, HRs and CIs that still excluded the null.

Conclusions

Higher intakes of dairy milk were associated with greater risk of breast cancer, when adjusted for soy intake. Current guidelines for dairy milk consumption could be viewed with some caution.