bluuebunny/crossref_metadata_2025 huggingface dataset:
Estimation of Normal Ranges and Cumulative Proportions by Transforming Observed Distributions to Gaussian Form
Authors: Harris Eugene K , DeMets David L
Published: January 2020

A sequence of transforming functions is proposed to convert nongaussian distributions often seen in laboratory data to gaussian form. These transforms are chosen to eliminate or substantially reduce nongaussian characteristics of positive skewness and peakedness that result from two factors: (a) increases in variance with increasing mean values, and (b) general heterogeneity among intrapersonal variances. Use of these transforms, demonstrated on many sets of clinical laboratory data, enables smooth curves to be drawn through observed cumulative distributions plotted on arithmetic or gaussian probability scales. From such curves, normal ranges or proportions below a specified measurement may be estimated easily and with greater precision than possible through nonparametric methods. Formulas are given for obtaining confidence limits corresponding to these estimates. The entire process of transforming the original variable to gaussian form and graphing the cumulative distribution curve has been computerized. Programs are available to others interested in applying these methods.
Continuous-Recording Flame Photometry of Sodium and Potassium in Serum
Authors: Amador Elias , Cechner Ronald L , Barklow James J
Published: January 2020

Serum sodium and potassium can be measured with a continuous-flow system that includes an AutoAnalyzer Sampler II and Proportioning Pump II, a miniature dialyzer, an Instrumentation Laboratories 143 flame photometer, and two strip-chart recorders. A simple interface allows the IL flame photometer to drive the two strip-chart recorders.
Computerized Automation in Acquisition and Processing of Patterns from High-Pressure Ion-Exchange Chromatography
Authors: Cerimele B J , Clapp D C , Cokinos G C , Obermeyer B D , Wolen R L
Published: January 2020

Fully automated generation, recording, storing, and processing of complex chromatograms demand sophisticated laboratory instrumentation and computer implementation. In the high-resolution liquid-chromatographic system for body fluids analyses we use in our clinical laboratory, the chromatograph is interfaced to a 2114 Hewlett-Packard minicomputer that accomplishes, in an on-line mode, analog-to-digital conversion, reductive averaging of sampled data, transformation from transmittance to absorbance units, and storage of the digitized spectrum on a peripheral disk. The information on disk is eventually transferred to a library of spectral files resident on a direct-access disk associated with an IBM 360/ Model 65 computer. These data files serve as the input source for program COCOA, written in Fortran IV for the IBM 360 computer, which provides the following processing: (a) iterative polynomial smoothing; (b) sectionally linear baseline tracking; (c) peak and envelope detection and delineation; (d) least-squares gaussian resolution of up to five component peaks in an envelope; and (e) location, size, and shape quantification of peaks. The capability and merits of program COCOA as an off-line procedure on a maxicomputer for the analysis of chromatograms are discussed.
A System for Computer Analysis of Kinetic Enzyme Data from a Modified Beckman DSA-560
Authors: Pearson J Richard , Pinfield Edward R , Cooper Daniel
Published: January 2020

We define the following criteria for enzyme assays as being beyond compromise: narrow bandpass double-beam spectrophotometer, multiple readings on the sample (kinetic procedure), temperature control of assay reaction mixture to ±0.1°C, wash-out between samples less than 1% of the preceding sample, and sample size of 100 µl or less. In addition, the following specifications for a system were considered desirable: automatic handling of the sample from initial pipetting through readout, adequate computer compatibility, versatility so that new procedures and different methods could be used, relatively short set-up time, and hard-copy backup in the event the computer failed. We have developed a system for enzyme assays that meets all of the above criteria. It consists of an analyzer (Beckman DSA-560) coupled to two modified Eskalab Spectrophotometers Alpha. The system is controlled via a special-purpose hybrid computer designed and built in our laboratory. Data from the system is analyzed on-line by an IBM 1800 computer. Details of the operation and reliability of the system in a routine clinical chemistry laboratory are discussed.
Chromatographic Analysis of Naturally Fluorescing Compounds: I. Rapid Analysis of Nanogram Amounts of Indoles in Physiologic Fluids
Authors: Chilcote D D , Mrochek J E
Published: January 2020

A chromatographic separation system has been developed for determination of various indole derivatives in physiologic fluids. A coupled-column configuration is used in which a 0.22 x 25 cm, jacketed, stainless-steel anion-exchange column is connected directly to a 0.22 x 50 cm, jacketed, stainless-steel cation-exchange column. The indole compounds are eluted with an ammonium acetate—acetic acid buffer that is 4 molar in ammonia and 5.8 molar in total acetate. An Aminco-Bowman spectrophotofluorometer, with an excitation setting of 292 nm and an emission setting of 330 nm, is used as the detector. The column temperature is 60°C. Effects of pH, temperature, and ionic strength on elution characteristics of the indole compounds have been investigated. The system can provide baseline separation of 50 to 100 ng of 5-hydroxytryptophan, tryptophan, 5-hydroxyindoleacetic acid, serotonin, indoleacetic acid, and tryptamine in 3 h. Use of the system in analyzing urine is illustrated.
Precautions in Use of Soft-Glass Disposable Pipets in Clinical Analyses
Authors: McCormick Patrick G , Burke R W , Doumas Basil T
Published: January 2020

Soft-glass, Pasteur-type pipets are widely used as disposable transfer pipets, especially in clinical and biochemical laboratories. These pipets possess an alkaline surface contamination that can affect the accuracy of chemical analyses if proper precautions are not taken. Microtitrations of aqueous rinsings from these pipets have consistently yielded values of 0.1 to 0.2 µmol of hydroxide equivalent per pipet. A possible detrimental effect of this residue was demonstrated, using chloroform solutions of bilirubin. Absorbance was diminished by as much as 5% when unwashed, soft-glass pipets were used to transfer these solutions to spectrophotometric cells. Absorption and fluorescence characteristics of other unidentified surface contaminants are also described. The effect of multiple rinsings is discussed and several ways are suggested for cleaning these pipets. Oven drying must be avoided, however, since it enhances alkali release.
Critical Evaluation of a New Flame Emission Analysis System, the "Klina Flame"
Authors: Schlesinger Richard J , Lesonsky Raymond A , Lottritz Robert
Published: January 2020

Recently there have been several advances in instrumental methods for the flame emission analysis of electrolyte cations of clinical significance. Greater precision and increased ease of operation are among today’s clinical requirements. This study compares a new automated flame photometer, "Klina Flame" (Beckman Instruments) with a "Techtron-AA5" atomic absorption emission unit (Varian Instruments) and an "IL 143" flame system (Instrumentation Laboratory). Day-to-day variation between paired data over a three-month period showed comparable and explainable similarities and variations between the three instruments. Results of lithium determinations gave favorable comparison statistics. Long-term stability on all the systems were generally comparable. A comparison of manual vs. automatic modes of dilution with serum samples of various viscosities generally gave predictable variation for instruments of similar quality. The piston dilutor feature of the Klina system seems to prevent the variability seen at higher viscosities when the IL system is used, which has a peristaltic dilutor.
Multi-Antisera Applicator for Use in Solid-Support Immunoelectrophoresis on Cellulose Acetate
Authors: Nerenberg Samuel T , Ganger Carolyn , DeMarco Linda
Published: January 2020

We describe for the first time a multi-antisera applicator to be used on cellulose acetate membranes with immunoelectrophoresis on a solid support. The new procedure overcomes previous shortcomings of immunoelectrophoresis on cellulose acetate membranes and permits rapid analyses of 11 samples on single "standard"-size membranes with a substantial saving in antisera, cellulose acetate membranes, and time.
Negative Interference by Residual Proteins in the Supernatant Fluid Used in Radioisotopic Assay of Serum Vitamin B12
Authors: Mortensen Esper
Published: January 2020

Separation of vitamin B12, from serum by heat denaturation results in an individually variable amount of residual protein in the supernatant fluid. I show that during radioisotopic assay of serum vitamin B12, such protein may seriously interfere with the results, and that the interference may be abolished by changing the experimental conditions.
Comparison of Manometric and Infrared Methods for Determining Carbon Monoxide in Blood
Authors: Myhre Loren G
Published: January 2020

Twelve samples of blood containing carbon monoxide (CO) ranging from 0.24 to 6.80 vol % were analyzed in duplicate by a manometric method and by two other methods in which an infrared CO meter is used. The analytical precision was within ±0.015 vol % for all methods, and the differences observed in blood CO between any two methods were not statistically significant. One of the methods with the infrared CO meter was preferred because, without sacrificing either precision or accuracy, it was considerably more convenient and technically less demanding than either of the other methods.
Spot Test for Detection of Sickling Hemoglobin
Authors: Kelly Sally , Desjardins Lucille
Published: January 2020

We designed a simple spot-plate method for detecting sickling hemoglobins and distinguishing hemoglobin SS from AS in samples of dried blood on filter paper. The test depends on the differential solubility of sickling hemoglobins in phosphate solutions with and without 3 molar urea. Paired phosphate and phosphate-urea hemolysates form color combinations that match those from control hemoglobins.
New Automated Method for Measuring Thiamine (Vitamin B1) in Urine
Authors: Pelletier Omer , Madère René
Published: January 2020

A new automated method was developed to eliminate the time-consuming steps of the manual procedure for the measurement of thiamine (vitamin B1) in urine. A Technicon Pump II simultaneously pumped 23 samples through chromatographic columns of "Decalso," washed out the interfering substances, and eluted thiamine. The automated procedure for determining thiamine with a Technicon AutoAnalyzer system involved the oxidation of thiamine to thiochrome, extraction into isobutanol and fluorescence measurements. Results obtained by the automated method correlated well with those obtained by the manual procedure. Recoveries of added thiamine were satisfactory and the results reproducible. This method was used successfully in the analysis of more than 10,000 urine samples for the Canadian Nutrition Survey.
Urea, Urease, Cyanate, and the Sickling of Hemoglobin S
Authors: Nalbandian Robert M , Nichols Bruce M , Stehouwer Edward J , Camp Frank R
Published: January 2020

Urea in glucose solutions has been advanced as a chemotherapeutic agent in sickle cell disease because it has been found effective both in reversing and in blocking sickling. It has been suggested recently that this beneficial action of urea may be the result of formation of cyanate from urea and subsequent carbamylation of beta S globin chains in the hemoglobin S molecule. In this paper, we show that the urea molecule per se interferes with sickling. SS cells in oxygen-free atmosphere, protected from sickling by urea— sugar solutions, were sickled after urease was added. Urea blocks and reverses sickling; ureaprotected sickle cells become sickled after incubation with urease; these effects are reversible and immediate, and are apparent in the deoxygenated state. In contrast, cyanate blocks but does not reverse sickling; cyanate-treated cells are unaffected by urease; these effects are permanent and require time; and hemoglobin S must first be oxygenated before carbamylation will occur. Evidently, urea and cyanate interfere with sickling by distinctly separate molecular mechanisms. Possible mechanisms for the action of urea are discussed.
Automated Vitamin C Analysis
Authors: Aeschbacher Hans U , Brown R Glenn
Published: January 2020

An automated method of analysis for vitamin C (ascorbic acid, dehydroascorbic acid, diketogulonic acid) is described, in which ascorbic acid as oxidized to dehydroascorbic acid with Chloramine-T and determined by reaction with 2,4-dinitrophenylhydrazine. Results obtained by automated and manual methods agreed within 0.89% for ascorbic acid in liver. By the automated method, 96.7% of ascorbic acid added to tissue homogenates could be accounted for. The principal drawback to the proposed method is the use of 70% perchloric acid, a potent oxidizing agent, to solubilize the osazone.
Trimethylsilylation of Malonate Ester Enols
Authors: Mamer O A , Tjoa S S
Published: January 2020

Malonic acid silylates readily to yield the expected bis-trimethylsilyl (TMS) ester; this ester reacts further in the silylating mixture to yield a tris-TMS derivative, apparently through enolization of one of the ester groups. Methylmalonic and hydroxymalonic acids behave similarly. The methyl and ethyl esters of malonic acid also silylate once with some facility. Mass spectra of these derivatives are presented
Electrophoresis, Specific Protein Assays, or Both in Measurement of Plasma Proteins?
Authors: Laurell Carl Bertil
Published: January 2020

Cumulative knowledge of the protein composition of plasma and newer techniques for specific analysis of proteins have made obsolete most flocculation tests, the albumin:globulin ratio, scanning diagrams, and most determinations of electrophoretic fractions. More clinically relevant information about the serum protein composition is obtained by critical visual evaluation of the protein bands obtained after electrophoretic separation of plasma or serum in nonadsorptive supporting media, if supplementary specific analysis is made of a small number of proteins such as albumin, orosomucoid, haptoglobins, ceruloplasmin, and the immunoglobulins of the three predominant classes
Nitrile-Terminated Hydrocarbons as Stationary Phases for High-Performance Liquid Chromatography of Steroid Hormones
Authors: Fitzpatrick Francis A
Published: January 2020

A high-performance liquid chromatographic method for separating steroid hormones by using nitrile-terminated hydrocarbons as the stationary phase is described. Particular selectivity toward the separation of corticosteroids with an α, β unsaturated ketone group is noted, with five steroids more polar than cortisol being completely resolved. The system described is also applicable to estrogen separations.
Automated Fluorometric Micromethod for Blood Glucose
Authors: Seiter Carl W , Hill Hoyle D , Summer George K
Published: January 2020

We describe a sensitive automated fluorometric method for glucose in whole blood spotted on filter paper. By action of glucose oxidase (EC 1.1.3.4) on glucose, hydrogen peroxide is produced, which then reacts with 4-hydroxy-3-methoxy-phenylacetic acid (homovanillic acid) in the presence of horseradish peroxidase (EC 1.11.1.7) to form a fluorescent condensation product. Obtained at a rate of 60 samples per hour, the results are accurate, linear, and reproducible. Whole blood glucose can be determined by this method with an error (CV) of less than 5%.
Ferric Chloride-Impregnated Silica Gel for Thin-Layer Chromatography of Steroids
Authors: Shapiro Daniel R , Kuwahara Steven S
Published: January 2020

Silica gel G is mixed with an aqueous solution of ferric chloride, and the resulting slurry spread onto glass plates. After spotting, development, and drying, the plates are sprayed with sulfuric acid. Cholesterol, ergosterol, and Δ5-pregnen-3β-ol-20-one produce colored spots (pink-violet, greenish black, and pink-violet, respectively) without further treatment, but some other steroids require heating at 70 °C for full color development. Other colors generated are: estrone, orange; Δ4-androsten-3,17-dione, blue-green; androsterone, light brown; and 5α-androstan-17β-ol-3-one, tan. After prolonged heating at 70 °C, 6-keto-cholestanol produces an orange-brown spot. Color reactions are more reproducible than they are when the ferric chloride is sprayed on the plate.
Gel Entrapment of Antibody: A New Strategy for Facilitating Both Manual and Automated Radioimmunoassay
Authors: Updike Stuart J , Simmons John D , Grant Douglas H , Magnuson Judith A , Goodfriend Theodore L
Published: January 2020

A technique of radioimmunoassay is presented that eliminates pipetting and centrifugation, and excludes interferences by high-molecular-weight materials from the incubation and separation steps. A solid-phase binding reagent is prepared by first entrapping antibody in polyacrylamide gel. This gel is then fragmented, sieved, dried with ethanol or lyophilized, and placed in miniature disposable chromatographic columns. Application of the sample to the intra-gel column compartment is determined by the water regain of the gel. This pipetless method of sample application depends on reproducible aliquots of dry gel particles in every column. A method for preloading radiolabeled hormone and standard hormone into the column is also described. This technique has been successfully applied to the assay of angiotensin I and insulin. Dry antibody—gel stored at room temperature for 26 months has not shown loss of binding activity.
Automated Assay of Hexosaminidases in Serum
Authors: Lowden J A , Skomorowski M A , Henderson F , Kaback M
Published: January 2020

In serum there are two classes of hexosaminidase. One of these is heat-labile and is inactive in children with Tay—Sachs disease. Serum from heterozygotes for Tay—Sachs disease has half the normal activity of the heat-labile enzyme. The heat-labile enzyme can be inactivated by heating serum diluted in buffer for 5 min at 60 °C. We have used this property to develop a reliable, fully automated assay for serum hexosaminidases, which can be used for mass carrier screening programs.
Single-Reagent Method for Rapid Determination of Total Bilirubin with the "CentrifiChem" Analyzer
Authors: Ertingshausen Gerhard , Byrd Diane L Fabiny , Tiffany Thomas O , Casey Sandra J
Published: January 2020

We report a rapid single-reagent method for determining total bilirubin with the " CentrifiChem Analyzer" (Union Carbide Corp.). The reagent is the stable 1,5-disulfonate of diazosulfanilic acid, and ethylene glycol is used as an accelerator. The reaction requires less than 5 min. Only 25 µl of serum is needed. We present precision data (x = 2.62 mg/dl, SD = .082 mg/dl, CV = 3.13%) and results (r = .998) as compared with those obtained by an automated Jendrassik—Grof method.
Factors Contributing to Intra-Individual Variation of Serum Constituents: 2. Effects of Exercise and Diet on Variation of Serum Constituents in Healthy Subjects
Authors: Statland Bernard E , Winkel Per , Bokelund Henning
Published: January 2020

A previous report of within-day variation of serum constituents was based on values in healthy subjects who did not undergo strenuous exercise and who were in a fasting state. In this study we consider the effects of exercise and of a noon meal on the same serum constituents. The statistical significance (t-test) was computed on the basis of the ratios of values (after/before) on the day of exercise vs. the ratios on the nonexercise day, or, for the effect of meal, the ratios of values (after/before the noon meal) on the eating day vs. the ratios of values taken at the same hour on the fasting day. Significant effects seen after exercise (P <.05) included: potassium, phosphate, creatinine, total protein, albumin, uric acid, and alanine aminotransferase. After the noon meal, significant (P <.05) changes were seen for: sodium, phosphate, uric acid, iron, total lipids, alkaline phosphatase (phenyl phosphate substrate), and lactate dehydrogenase. The effects of eating on serum constituents are separated into (a) physiological factors and (b) methodological considerations.
A Sensitive, Rapid Radioimmunoassay for Morphine and Immunologically Related Substances in Urine and Serum
Authors: Catlin Don , Cleeland Roy , Grunberg E
Published: January 2020

A rapid, simple radioimmunoassay for morphine and immunologically related compounds is described and evaluated. The 2-h assay requires as little as 0.1 ml of urine or serum and provides a quantitative estimate of serum or urinary morphine. Individuals known not to be receiving heroin or other narcotics had apparent urinary morphine concentrations of less than 25 µg/liter and apparent serum concentrations of less than 10 µg/liter. Patients receiving as much as 100 mg of methadone gave results (expressed as morphine) of less than 25 or 10 µg/liter, respectively, for their serum and urine. Fifty-eight of 59 urines from known heroin users, sampled up to 48 h after self-administered heroin, contained more than 25 µg of morphine per liter; 32 of 37 sera obtained up to 12 h after heroin contained more than 10 µg/liter. Samples obtained from individuals receiving substances that may cross-react in the assay were tested and the results are discussed. We conclude that this radioimmunoassay may be suitable for routine screening of urine or serum for morphine.
Polyacrylamide-Gel Block-Electrophoresis of Plasma Lipoproteins
Authors: Wada Mitsuo , Naito Herbert K , Ehrhart L A , Lewis Lena A
Published: January 2020

We separated lipoprotein fractions on a preparative scale by two techniques of polyacrylamide-gel block electrophoresis. Completeness of separation of the various lipoproteins, which were subsequently extracted from the gels, was verified by re-electrophoresis and by immunologic techniques. A principal advantage of this method over ultracentrifugal isolation is the relatively short time required for the separation.
Evaluation of a Glucose Oxidase-Peroxidase Method Adapted to the Single-Channel AutoAnalyzer and SMA 12/60
Authors: Miskiewicz Stanley J , Arnett Bill B , Simon Gerald E
Published: January 2020

The glucose oxidase—peroxidase method for determining serum glucose, with the ammonium salt of 2,2'-azine-di - (3 - ethyl - benzothiazoline-(6)-sulfonic acid) as the chromogen, was adapted to use with the single-channel AutoAnalyzer and the SMA 12/60 (Technicon Corp.). The extended linearity (up to 500 mg/100 ml on both systems) eliminated the need for numerous dilutions in the 300 to 500 mg/100 ml range as required by other methods of analysis. Recovery of added glucose was excellent. Supranormal concentrations of uric acid and ascorbic acid interfered with recovery, but the effects of elevated bilirubin, creatinine, and urea, and of gross hemolysis were negligible. Sera of 337 patients (glucose concentrations: 50 to 454 mg/100 ml) were analyzed by this method on both instruments and by an automated o-toluidine method. By the latter procedure, the glucose concentration averaged 10 mg/100 ml higher. Sera from uremic patients, measured by the o-toluidine method, had glucose values up to 28.0 mg/100 ml higher than the values obtained by the glucose oxidase method. The glucose oxidase method of measuring serum glucose is a more accurate and precise index of "true glucose" than either the o-toluidine or the neocuproine methods.
Toxicological Findings in Fatal Poisonings
Authors: McBay Arthur J
Published: January 2020

Anyone who must decide whether the amount of toxic substance present in a specimen is sufficient to indicate that the substance may have been the cause of death is aware of the difficulty of finding information to guide that decision. Opinions are given concerning therapeutic and toxic concentrations in human tissues for most of the common drug and chemical poisons. These include alcohols, amitriptyline, amphetamine, arsenic, barbiturates, boron, bromides, carbon monoxide, chloral hydrate, chlordiazepoxide, cyanide, diazepam, diphenylhydantoin, ethchlorvynol, fluoride, glutethimide, heroin (morphine), imipramine, lead, LSD, marihuana, meperidine, meprobamate, methadone, methamphetamine, methaqualone, nicotine, nortriptyline, orphenadrine, paraldehyde, pentazocine, phenothiazines, propoxyphene, quinine, salicylates, and strychnine.
Gradient Gel Electrophoresis of Human Plasma Lipoproteins
Authors: Bautovich G J , Dash M J , Hensley W J , Turtle J R
Published: January 2020

A rapid and simple method for separating and identifying plasma lipoproteins is described. The technique utilizes the "molecular sieving" properties of continuous concave gradient electrophoresis on a slab of polyacrylamide (4 to 26%) gel. Gradient gel electrophoresis is particularly suitable for separating lipoproteins according to their molecular weight. The technique can be used to demonstrate the major lipoprotein classes in normal plasma and to identify abnormalities of lipoprotein metabolism. Components of a sample are better resolved by gradient gel electrophoresis than by electrophoresis on paper or cellulose acetate. The results obtained compare favorably with those achieved by preparative ultracentrifugation. The technique is easily and rapidly performed in a routine clinical laboratory.
Reduction of Glyoxylate by Human Serum
Authors: Young G , Naghizadeh F , King J , Morgan H G
Published: January 2020

Glyoxylate is enzymically reduced by human serum. Optimal concentrations of hydrogen ion, substrate, and coenzyme for this reduction by sera from healthy persons and from patients with disease of the heart or liver have been determined at 37°C. At this temperature, the reaction proceeds faster than with pyruvate or 2-oxobutyrate but more slowly than with hydroxypyruvate. Lactate dehydrogenase appears to be the enzyme involved.
Quantitative Determination of Serum Triglycerides by the Use of Enzymes
Authors: Bucolo Giovanni , David Harold
Published: January 2020

We describe a novel method for determining serum triglycerides, in which an enzymatic hydrolysis replaces the more commonly used saponification procedure. Under the conditions of the assay, the enzymatic hydrolysis can be completed in less than 10 min by the combined action of a microbial lipase and a protease. We have been able to demonstrate complete hydrolysis of triglycerides by thin-layer chromatography of the reaction products, by recovery of glycerol from sera of known triglycerides content, and by comparison of triglyceride assays on a number of sera assayed by our method vs. the AutoAnalyzer procedure. The hydrolysis is directly coupled to the enzymatic determination of glycerol, and is followed through absorbance changes at 340 nm. The assay is simple, rapid, and requires only 50 µl or less of sample. Because the enzymes used do not release glycerol from other compounds in serum, the hydrolysis can be considered specific for triglycerides.
Improved Measurement of Corticosteroids in Plasma and Urine by Competitive Protein-Binding Radioassay
Authors: Ficher Miguel , Curtis George C , Ganjam V K , Joshlin Leon , Perry Sarah
Published: January 2020

In the assay of corticosteroids in plasma and urine by competitive protein binding, the use of horse serum or plasma as a source of assay protein gives better sensitivity and somewhat better specificity for cortisol than do previously described procedures. Five to 10 µl of plasma unknown or 50 to 100 µl of urine unknown can be used. Precision for the standard curve is 0.12 ng in the range 0-2.00 ng, and accuracy, measured as the amount of added cortisol recovered from plasma, is about 91%. Because of the improved specificity, the need for preliminary purification by chromatography is decreased for some purposes. The same corticosteroid-binding globulin and standard curve can be used for assaying corticosteroids in urine or plasma. The procedure may be useful for unusually small samples or if discriminations within the lower range of physiological concentrations are needed, as in work with infants and neonates or in the study of small adrenal secretory pulses, such as those occurring at the nadir of the circadian cycle.
Automated Atomic Absorption Spectrophotometry
Authors: Gitelman H J , Soucek C , Owen J F
Published: January 2020

Diluting continuous-flow circuits that incorporate a jet mixer with conventional AutoAnalyzer equipment provide a convenient technique for supplying diluted samples to an atomic absorption spectrophotometer at rates up to 90 per hour.
Effect of the Use of Cholesterol Digitonide in Standards on the Results of Estimation of Cholesterol in Blood and Tissues by the Schoenheimer—Sperry Method
Authors: Rao A Venugopala , Ramakrishnan S
Published: January 2020

In the classic Schoenheimer—Sperry method for estimating cholesterol [J. Biol. Chem. 106, 745 (1934)] it is selectively precipitated with digitonin, and interference by other substances is minimized. The standards used in the color development are pure cholesterol. We suggest that the standard cholesterol should also be converted to cholesterol digitonide and treated identically to the test samples. When this is done, the values for cholesterol in test samples are significantly higher, both for free and total cholesterol in blood serum and for total cholesterol in tissues. Moreover, recovery experiments showed that error is diminished. Values for serum total cholesterol obtained when cholesterol digitonide standards were used were closer to those obtained by the method of Abell et al. than when pure cholesterol standards were used.
Comparison of Results by Four Different Procedures for Determination of 17-Hydroxycorticosteroids
Authors: Bruton Joseph , Li Ting-Kai , Smith Gerald D
Published: January 2020

A Porter and Silber procedure, a fluorometric procedure, a double-isotope derivative procedure, and a competitive protein-binding assay procedure were used to determine 17-hydroxycorticosteroids in plasma from normal individuals and from patients with endocrinopathies. Results from each of these procedures were intercompared. Results of the fluorometric procedure and the competitive protein-binding assay compared favorably with results obtained by the more elaborate and difficult double-isotope derivative method. The Porter and Silber method is less specific. This study should be a useful aid in comparing values with those of other laboratories and in selecting the most advantageous method for use by a particular laboratory.
Efficiency and Sensitivity of Two Common Screening Methods for Detecting Morphine in Urine
Authors: Gorodetzky Charles W
Published: January 2020

Modified procedures are described for extracting morphine from urine with organic solvents and with paper impregnated with ion-exchange resin, followed by detection by thin-layer chromatography. I propose that efficiency of extraction (percent recovery) be defined in terms of the amount of drug reaching the detection system vs. the amount in the total urine sample analyzed. Percent recoveries were determined experimentally with 95% confidence limits and 95%, P = .05 tolerance limits, and were 60.6% for the organic solvent procedure and 48.2% for the ion-exchange paper procedure. Sensitivity of the overall detection method can be defined as the concentration of drug in the urine detectable at least 99% of the time. Values (95% confidence limits) determined experimentally were 0.19 (0.14-0.25) µg/ml for the organic solvent procedure and 0.16 (0.07-0.35) µg/ml for the ion-exchange paper procedure.
Problems in the Laboratory Diagnosis of Alcaptonuria
Authors: Frohlich Jiri , Price George E , Campbell Donald J
Published: January 2020

Two patients with urinary findings suggestive of alcaptonuria were observed. One was a two-year-old girl of Turkish descent, presenting with dark-stained diapers, black ear wax, and no other stated problem. The second was a 61-year-old North American Indian woman with long-standing rheumatoid arthritis, bluish sclerae, chronic renal failure, and dark urine. Diagnosis of alcaptonuria was confirmed in the first case by paper chromatographic identification of homogentisic acid in urine and ear wax; also a small amount of a substance with Rf similar to that of homogentisic acid was found in urine of the patient's mother and brother. Whether this implies possibilities for heterozygote detection requires further study. Gentisic acid, a phenolic acid metabolite of acetylsalicylic acid, was responsible for the dark color of the urine in the second patient. This latter finding has not been emphasized in this context, and may cause confusion when patients with arthritis and pigmentation are investigated for possible alcaptonuria.
Electronic Cell-Volume Analysis by Use of the AMAC I Transducer
Authors: Leif R C , Thomas R A
Published: January 2020

A new potential-sensing transducer has been developed that produces short 5- to 10-µs pulses suitable for rapid cell counting and pulse height volume analysis rates. The use of a bridge circuit, where potential-sensing rather than current-carrying electrodes are connected to a differential amplifier with a high common-mode rejection ratio, permitted accurate determination of both pulse width and shapes from the short pulses generated with the transducer. A new sample injection subsystem permits small samples of constant volume to be continuously mixed at a variable rate with a constant flow of diluent. The counting rate can be optimized to 250,000 cells per minute at a 2% coincidence level. Polystyrene latex spheres produced pulses having the five basic shapes predicted by Grover et al. [Biophys. J. 9, 1398 (1969)]. Human erythrocytes produced, in addition to these shapes, a sixth, castle-shaped pulse, presumably caused by rotation or distortion of the erythrocyte as it passes through the orifice. A shape factor has been calculated from the latter pulses. The electronic cell-volume pulses from the tranducer trigger an pulsed-ion laser. The 5-W peak power beam is focused through the orifice. Illumination of the cells with this intense but economical light source permits the combined measurement of electronic cell volume, fluorescence, and light scattering.
Automated Method for Serum Glucose with p-Hydroxybenzoic Acid Hydrazide
Authors: Fingerhut Benjamin
Published: January 2020

A new automated method for serum glucose is presented, based on the reaction between glucose and p-hydroxybenzoic acid hydrazide in alkaline solution. Results for 70 non-uremic sera averaged 60 mg/liter greater than those given by an automated glucose oxidase (EC 1.1.3.4) procedure. Values for uremic sera indicated the proposed method to be more specific for such sera than is the automated ferricyanide-reduction technique. Within-run and day-to-day values had a standard deviation of 17 and 32 mg/ liter, respectively. Recoveries ranged from 99.5 to 104.5% (mean, 102.2%).
Radioimmunoassay of Digoxin: An Intercomparison of Results with Three Methods
Authors: Gutcho Sidney , McCarter Henry , Rapun Raul
Published: January 2020

The radioimmunoassay of digoxin has been examined by comparing RIA data obtained by a clinical laboratory using the method of Smith et al. [New Engl. J. Med. 281, 1212 (1969)] with data obtained in a laboratory using commercially produced [3H]digoxin and [125I]digoxin kits. Correlations between clinical laboratory data and the results with each kit and correlation between kits are presented. The effects of digoxin-free sera and plasmas on standard curves have been examined.
Propylene Glycol Interference in Determination of Serum and Liver Triglycerides
Authors: Lenz Paul H , Cargill D Innes , Fleischman Alan I
Published: January 2020

Single intraperitoneal injections (of 0.5, 1.0, and 2.0 ml per kilogram body weight) of a solution of sodium pentobarbital (50 mg/ml, in propylene glycol, 40 ml/100 ml) elevated rat serum triglyceride values obtained by the semi-automated fluorometric method of Kessler and Lederer. Increases of 267, 619, and 813%, respectively, were noted within 5 min. Liver triglycerides and other major lipid fractions in serum and liver were unaffected. The solution added directly to pooled rat sera in vitro also elevated the apparent triglyceride concentrations, propylene glycol being the responsible agent. Essentially all of the propylene glycol was recovered as apparent triglyceride. This type of chemically induced artifact can be corrected for by determining a blank on each unknown (i.e., the hydrolysis step is omitted from the procedure). Subtraction of the blank concentration from the total triglyceride concentration yields the true triglyceride concentration. Extraction of the unknown by the Folch procedure also eliminates interference from propylene glycol.
Effects of Lysine on Ammonia Formation, Hydrogen Ion, and Potassium Ion Balance: A Review and an Hypothesis
Authors: Zweig Jack I
Published: January 2020

Evidence is assembled that lysine acts as an intracellular hydrogen ion acceptor, causing increased ammonia formation and increased potassium excretion in certain disease states. It is suggested that other intracellular dibasic amino acids may have the same effects.
Plasma Retinol Assay by Elution from Silicic Acid with Cymene (p-Isopropyl Toluene)
Authors: Pollack J Dennis , Owen George M , Garry Philip J , Clark Donna
Published: January 2020

We developed a microcolumn adsorption chromatographic technique for assay of plasma retinol. A petroleum ether extract of plasma was fractionated on silicic acid, to isolate retinol. The first eluent, petroleum ether, removed "unidentified fluorescent contaminant" (UFC); the second eluent, cyclohexene, removed traces of UFC and retinyl palmitate. Retinol was eluted by the third eluent, cymeme (p-isopropyl toluene). No recognized plasma vitamin A derivatives, other than retinol, were detectable in the cymene eluate. With the procedure, we could detect a minimum concentration of 7 µg of retinol per deciliter of plasma. Sixty-six plasmas from preschool children were assayed by our "cymene assay," and by the Neeld—Pearson modification of the Carr—Price procedure, the method of Thompson et al., and the column assay of Garry et al. Results by the latter three procedures were similar (P >0.025): the mean plasma retinol ranged from 29.4 to 31.2 (SD, ± 5.8 to 7.4) µg/dl. By the present assay the same samples contained 24.5 (SD, ± 6.8) µg/dl; significantly more was detected by the other procedures (P <0.001). This difference (16-22%) between the cymene assay for retinol and other assays for total vitamin A may reflect, in part, the concentration of other vitamin A derivatives in plasma.
Evaluation of Direct and Indirect Coupled Enzyme Assay Systems for Measurement of Creatine Kinase Activity
Authors: Dinovo E C , Miyada D S , Nakamura R M
Published: January 2020

Direct assay of creatine kinase by the method of Siegel and Cohen with the Technicon "SMA 12/60" is compared with two indirect coupled-enzyme assay methods. The direct method was linear to greater than 2000 U/liter, whereas the indirect methods were linear to 250 and 1500 U/liter, with use of serial dilutions of a creatine kinase preparation. Increasing the activity of the auxiliary enzymes, hexokinase and glucose-6-phosphate dehydrogenase, in one of the coupled enzyme assay methods increased its linear range from 250 to 700 U/liter. The observed findings are explained on the basis of the fundamental differences between direct and indirect coupled-enzyme assay systems and, within the latter system, the effect of the activities of auxiliary enzymes.
Predicted Drosophila Interactome Resource and web tool for functional interpretation of differentially expressed genes
Authors: Ding Xiao-Bao , Jin Jie , Tao Yu-Tian , Guo Wen-Ping , Ruan Li , Yang Qiao-lei , Chen Peng-Cheng , Yao Heng , Zhang Hai-bo , Chen Xin
Published: January 2020

Drosophila melanogaster is a well-established model organism that is widely used in genetic studies. This species enjoys the availability of a wide range of research tools, well-annotated reference databases and highly similar gene circuitry to other insects. To facilitate molecular mechanism studies in Drosophila, we present the Predicted Drosophila Interactome Resource (PDIR), a database of high-quality predicted functional gene interactions. These interactions were inferred from evidence in 10 public databases providing information for functional gene interactions from diverse perspectives. The current version of PDIR includes 102 835 putative functional associations with balanced sensitivity and specificity, which are expected to cover 22.56% of all Drosophila protein interactions. This set of functional interactions is a good reference for hypothesis formulation in molecular mechanism studies. At the same time, these interactions also serve as a high-quality reference interactome for gene set linkage analysis (GSLA), which is a web tool for the interpretation of the potential functional impacts of a set of changed genes observed in transcriptomics analyses. In a case study, we show that the PDIR/GSLA system was able to produce a more comprehensive and concise interpretation of the collective functional impact of multiple simultaneously changed genes compared with the widely used gene set annotation tools, including PANTHER and David. PDIR and its associated GSLA service can be accessed at http://drosophila.biomedtzc.cn.
Social Class, Work-Related Incomes, and Socio-Economic Polarization in Europe, 2005–2014
Authors: Albertini Marco , Ballarino Gabriele , De Luca Deborah
Published: January 2020

Sociologists and economists have typically focused on different dimensions of socio-economic inequalities. Sociologists have been mainly concerned with occupational and educational indicators, whereas economists have focused on the earnings, income, and wealth distribution. The article integrates sociological and economics’ approaches to the study of socio-economic inequalities, by providing an analysis of the relationship between social class and work-related income, and its distribution, in Europe in the period between 2005 and 2014. Europe as a whole and its eight major countries are studied with the European Union Statistics on Income and Living Conditions (EU-Silc) data. Changes in the income hierarchy among classes are discussed in the framework of the occupational upgrading and polarization hypotheses. The results of our analyses suggest that, first, the capacity of the concept of social class to describe and summarize the different distribution of individual market-related income is stable or increasing in Europe. Second, in the 10 years considered there has been a ‘fanning out’ of the class income hierarchy. With reference to upper social class, the increase in the income gap has been stronger for the self-employed and the routine workers. Finally, there is also evidence of a mix of occupational upgrading and polarization. The empirical results, in particular, are consistent with the predictions of the skill-biased technological change hypothesis.
Cardiovascular magnetic resonance in immune checkpoint inhibitor-associated myocarditis
Authors: Zhang Lili , Awadalla Magid , Mahmood Syed S , Nohria Anju , Hassan Malek Z O , Thuny Franck , Zlotoff Daniel A , Murphy Sean P , Stone James R , Golden Doll Lauren Alexandra , Alvi Raza M , Rokicki Adam , Jones-O’Connor Maeve , Cohen Justine V , Heinzerling Lucie M , Mulligan Connor , Armanious Merna , Barac Ana , Forrestal Brian J , Sullivan Ryan J , Kwong Raymond Y , Yang Eric H , Damrongwatanasuk Rongras , Chen Carol L , Gupta Dipti , Kirchberger Michael C , Moslehi Javid J , Coelho-Filho Otavio R , Ganatra Sarju , Rizvi Muhammad A , Sahni Gagan , Tocchetti Carlo G , Mercurio Valentina , Mahmoudi Michael , Lawrence Donald P , Reynolds Kerry L , Weinsaft Jonathan W , Baksi A John , Ederhy Stephane , Groarke John D , Lyon Alexander R , Fradley Michael G , Thavendiranathan Paaladinesh , Neilan Tomas G
Published: January 2020

Aims

Myocarditis is a potentially fatal complication of immune checkpoint inhibitors (ICI). Sparse data exist on the use of cardiovascular magnetic resonance (CMR) in ICI-associated myocarditis. In this study, the CMR characteristics and the association between CMR features and cardiovascular events among patients with ICI-associated myocarditis are presented.

Methods and results

From an international registry of patients with ICI-associated myocarditis, clinical, CMR, and histopathological findings were collected. Major adverse cardiovascular events (MACE) were a composite of cardiovascular death, cardiogenic shock, cardiac arrest, and complete heart block. In 103 patients diagnosed with ICI-associated myocarditis who had a CMR, the mean left ventricular ejection fraction (LVEF) was 50%, and 61% of patients had an LVEF ≥50%. Late gadolinium enhancement (LGE) was present in 48% overall, 55% of the reduced EF, and 43% of the preserved EF cohort. Elevated T2-weighted short tau inversion recovery (STIR) was present in 28% overall, 30% of the reduced EF, and 26% of the preserved EF cohort. The presence of LGE increased from 21.6%, when CMR was performed within 4 days of admission to 72.0% when CMR was performed on Day 4 of admission or later. Fifty-six patients had cardiac pathology. Late gadolinium enhancement was present in 35% of patients with pathological fibrosis and elevated T2-weighted STIR signal was present in 26% with a lymphocytic infiltration. Forty-one patients (40%) had MACE over a follow-up time of 5 months. The presence of LGE, LGE pattern, or elevated T2-weighted STIR were not associated with MACE.

Conclusion

These data suggest caution in reliance on LGE or a qualitative T2-STIR-only approach for the exclusion of ICI-associated myocarditis.
Atropine-induced sinus tachycardia protects against exercise-induced ventricular arrhythmias in patients with catecholaminergic polymorphic ventricular tachycardia
Authors: Kannankeril Prince J , Shoemaker M Benjamin , Gayle Kathryn A , Fountain Darlene , Roden Dan M , Knollmann Bjorn C
Published: January 2020

Aims

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited arrhythmia syndrome characterized by exercise-induced ventricular arrhythmias, sudden death, and sinus bradycardia. Elevating supraventricular rates with pacing or atropine protects against catecholaminergic ventricular arrhythmias in a CPVT mouse model. We tested the hypothesis that increasing sinus heart rate (HR) with atropine prevents exercise-induced ventricular arrhythmias in CPVT patients.

Methods and results

We performed a prospective open-label trial of atropine prior to exercise in CPVT patients (clinicaltrials.gov NCT02927223). Subjects performed a baseline standard Bruce treadmill test on their usual medical regimen. After a 2-h recovery period, subjects performed a second exercise test after parasympathetic block with atropine (0.04 mg/kg intravenous). The primary outcome measure was the total number of ventricular ectopic beats during exercise. All six subjects (5 men, 22–57 years old) completed the study with no adverse events. Atropine increased resting sinus rate from median 52 b.p.m. (range 52–64) to 98 b.p.m. (84–119), P = 0.02. Peak HRs (149 b.p.m., range 136–181 vs. 149 b.p.m., range 127–182, P = 0.46) and exercise duration (612 s, range 544–733 vs. 584 s, range 543–742, P = 0.22) were not statistically different. All subjects had ventricular ectopy during the baseline exercise test. Atropine pre-treatment significantly decreased the median number of ventricular ectopic beats from 46 (6–192) to 0 (0–29), P = 0.026; ventricular ectopy was completely eliminated in 4/6 subjects.

Conclusion

Elevating sinus rates with atropine reduces or eliminates exercise-induced ventricular ectopy in patients with CPVT. Increasing supraventricular rates may represent a novel therapeutic strategy in CPVT.