bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improved Techniques for Assessment of Serum Lipoprotein Patterns. II. Rapid Method for Diagnosis of Type III Hyperlipoproteinemia without Ultracentrifugation
Authors: Wieland Heinrich , Seidel Dietrich 
Published: January 2020

Abstract
Based on the previously described technique [Clin. Chem.19, 737 (1973)] of precipitating plasma lipoproteins with polyanions after their electrophoretic separation in gels, a new method is presented for diagnosing type III hyperlipoproteinemia without need for ultracentrifugation or immunologic techniques. Used in the procedure are 0.1 mol/liter MgCl2, 1.5 g/liter heparin, and 10 g/liter NaCl to visualize selectively the very-low-density lipoproteins in agarose gel after electrophoresis. The technique is simple, inexpensive, accessible to every laboratory, and provides the answer in less than 2 h after electrophoresis of the patient’s whole serum. The results obtained are the same as those obtained by ultracentrifugation followed by lipoprotein electrophoresis of the isolated fractions.
A Turbidimetric Continuous-Flow System for Immunochemical Quantitation of Blood Proteins by Use of a Modified Photometer
Authors: Blom Mogens , Sørensen Darly 
Published: January 2020

Abstract
In a continuous-flow procedure, the turbidity resulting from the reaction between albumin and transferrin and specific anti-human sera has been measured in a photometer constructed for the purpose. Incorporation of two photoelectric cells and a special bridge built between the photometer and the recorder made possible the amplification of the sensitivity by as much as 30-fold. Further, a more economical intermittent flow of antiserum was used. The standard deviations for sera analyzed in duplicate (day-to-day) were 1.4 and 0.05 g/liter, respectively, for albumin and transferrin determinations. Values obtained by this method correlated well with values obtained by the electroimmunotechnique.
Urinary Proteins Studied by Use of Isoelectric Focusing. I. Tubular Malfunction in Association with Exposure to Cadmium
Authors: Vesterberg O , Nise G 
Published: January 2020

Abstract
Isoelectric focusing in thin-layer polyacrylamide gel has been applied to studies of urinary proteins. We could differentiate the following patterns: tubular, glomerular with high and low selectivity, as well as mixed glomerular and tubular patterns, as seen in some cases of chronic pyelonephritis and uremia. The typical tubular-protein patterns—i.e., as developed in association with cadmium exposure—were characterized by elevated excretion of β2-microglobulin. Possibly the severity of renal malfunction can be assessed by the isoelectric focusing technique. To identify the protein zones, we in some cases complemented isoelectric focusing with electrophoresis at right angles in acrylamide gel and also in agarose gel containing antibodies to provide additional information.
Assessment of the Need for Triglyceride Blank Measurements
Authors: Rautela Gopal S , Slater Suzanne , Arvan Dean A 
Published: January 2020

Abstract
Two methods of triglyceride blank measurement were critically investigated. For 38 samples a mean blank value of 7.2 mg/dl was obtained when the blanks were measured by replacing the saponifying reagent with 80% isopropanol. For the same samples, consistently higher blank values were obtained (mean = 18.3 mg/dl) when these were determined by the Kessler-Lederer method. It is suggested that, when true blank values are desired, the former method is to be preferred. Based on theoretical considerations, however, as well as on our experimental data on the effect of in vitro hydrolysis on triglyceride blank measurements, we recommend that in routine triglyceride measurements, blank determinations are not needed.
Use of "Sephadex G-15" in an Improved Method for Estrogens in Pregnancy Urine
Authors: Quek Evelyn S C , Buttery J E , de Witt G F 
Published: January 2020

Abstract
A simple, rapid, and reliable colorimetric method has been developed for determining total estrogens in the urine of pregnant women. It is essentially a modification of the procedure of Van Baelen et al. [J. Clin. Endocrinol.27, 1056 (1967)], in which gel adsorption is used as a purification step after enzymatic hydrolysis. Three major modifications have been made to the original procedure, whereby a single determination can be completed within 4 h. Actual manipulative time of the analysis is only 2 h, and one technician can easily handle an average of 10 cases per batch. Precision of the method is good, the coefficient of variation being less than 5%. Recovery of added estriol is better than 95%. The method can be used for measuring estrogen excretions ranging from 0.5-50 mg/24 h. We have found it very suitable as a routine assay in our laboratory.
Use of a Sodium Chloride—Phosphate Buffer for pH Standardization in a New Blood-Gas Analyzer with an Isotonic Sodium Chloride Bridge
Authors: Drinker P A , Noonan D C , Ramanaiah N , Tole J R 
Published: January 2020

Abstract
Two different blood-gas analyzers were tested to determine the effects on blood pH measurement of changing the reference bridge solution from saturated KCl to normal saline (0.16 mol of NaCl per liter). This change, which necessitated the preparation of modified buffers equimolal in NaCl with respect to blood, virtually eliminated salt depletion of the bridge solution and improved the stability of the liquid-junction potential between the bridge solution and the sample. The instruments we used were the Corning 165 pH Blood Gas Analyzer and the Radiometer E5021 pH Electrode with PHM72 Acid Base Analyzer. Comparison of results on clinical blood samples indicates that performance with the modified bufferbridge system is the same as that obtained with the conventional scheme. Analytical performances of the Corning and Radiometer instruments for PO2 and PCO2, as well as for pH, were comparable.
A Test for Bacterial Alkaline Phosphatase: Use in Rapid Identification of Serratia Organisms
Authors: Wolf Paul L , Von der Muehll Elisabeth , Praisler Karen 
Published: January 2020

Abstract
This investigation concerns identification of alkaline phosphatase production by bacterial organisms, as detected by a blue color resulting from conversion of indolyl phosphate to indigo. Coagulase-positive Staphylococcus produced alkaline phosphatase; coagulase-negative Staphylococcus did not. Serratia did not produce alkaline phosphatase; those Enterobacteriaceae we tested did. Thus, this test rapidly differentiates these organisms, diminishing the time for identification of Serratia in the clinical laboratory by 48 h. Identification of Serratia should not be ignored, because it is a life-threatening complication for certain hospitalized patients.
Design and Evaluation of a Filter Fluorometer That Incorporates a Photon-Counting Detector
Authors: Curry Robert E , Pardue Harry L , Mieling Glen E , Santini Robert E 
Published: January 2020

Abstract
We describe the design and evaluation of a filter fluorometer in which a photomultiplier detector is used in the photon-counting mode. Output frequency is shown to be linear with light intensity from 5 Hz to 800 kHz. Comparisons with commercially available instruments show an inherent sensitivity superior to a commercially available filter instrument and comparable to that of a spectrofluorometer. Results are included showing the applicability of the instrument to the kinetic determination of lactate dehydrogenase in serum.
Improved Automated Determination of Bound N-Acetylneuraminic Acid in Serum
Authors: Gerbaut Lucile , Rey Elisabeth , Lombart Christian 
Published: January 2020

Abstract
The method in which thiobarbituric acid is used for sialic acid determination was adapted to a fully automated procedure, in which the chromogen need not be extracted with an organic solvent. The entire procedure, including hydrolysis, requires 35 min and 25 µl of serum for one analysis, but 30 samples can be analyzed per hour. The procedure, slightly modified, can be used to measure as little as 10 mg of bound sialic acid per liter.
Comparison of Two Methods for Radioassay of Vitamin B12 in Serum
Authors: Frenkel Eugene P , White Jerry D , Reisch Joan S , Sheehan Richard G 
Published: January 2020

Abstract
A reference radioassay for vitamin B12 in serum, in which human serum is used as binder and DEAE-cellulose is used to separate free and bound B12, was compared (194 sera) with a packaged kit (" Phadebas B12 Test"), in which intrinsic factor is used as binder and polysaccharide for separation. The correlation coefficient was 0.949. With the kit, added B12 was identifiable, proportional dilution characteristics were excellent, and serial reproducibility was good. The normal range for the reference assay was 200-1000 pg/ml; all B12-deficient patients had values of &lt;165 pg/ml. In a separate study, 38 patients with documented (clinical and laboratory) B12 deficiency had mean serum values of &lt;150 pg/ml by the reference assay, 250 pg/ml by the kit. For the kit, the normal range was 250-1100 pg/ml. All patients with serum values of &lt;150 pg/ml by kit assay were B12 deficient; false positives were seen in the 150-250 pg/mI range.
Comparison of Diagnostic Accuracy of α-Hydroxybutyrate Dehydrogenase Assays by Two Spectrophotometric Procedures
Authors: Spooner Richard J , Goldberg David M 
Published: January 2020

Abstract
α-Hydroxybutyrate dehydrogenase activity was measured in 66 sera from cases of myocardial infarction and 91 sera from cases of hepatobiliary disease by the original procedure at 25 °C [Nature 188, 1110 (1960)] and the revised procedure at 37 °C [Amer. J. Clin. Pathol. 56, 627 (1971)]. The diagnostic accuracy of the two procedures was comparable, but the superior precision of the revised procedure makes it more suitable as a laboratory routine.
Simple, Rapid Determination of Lecithin and Sphingomyelin in Amniotic Fluid
Authors: Blass K G , Thibert R J , Draisey T F 
Published: January 2020

Abstract
We describe a rapid and very sensitive modified determination of lecithin and sphingomyelin in amniotic fluid. It requires 1.5 ml of amniotic fluid and can be done in less than 40 min. Modifications include "Instant Thin Layer Chromatography" plates (Gelman) with a punched disc system of sample application, as well as elimination of the acetone wash steps, and substitution of Rhodamine B dye for the corrosive sulfuric acid char technique of detection. The procedure can be quantified, and exact concentrations of lecithin in amniotic fluid can be determined by a standard addition procedure, or from a standard curve.
Overnight Radioimmunoassay of Human Follicle-Stimulating Hormone
Authors: Brown Loretta P , Besch Paige K , Skelley Dean S , Buttram Veasy C 
Published: January 2020

Abstract
A radioimmunoassay procedure for follicle-stimulating hormone in serum has been developed in which the assay mixture is incubated at 37°C for a total of 22 h, rather than at 4°C for 4-7 days. The within-assay coefficients of variation for the 37°C and 4°C methods, respectively, are 7.7% and 5.0%, while the between-assay variations are 13.8% and 9.9%. Comparison of values for 4°C (x) were related to values for 37°C (y) according to the equation y = 1.2x + 0.8, with a correlation coefficient of 0.98.
Rapid Single-Step Kinetic Colorimetric Assay for Lactate Dehydrogenase in Serum
Authors: Allain Charles C , Henson Carl P , Nadel M Keith , Knoblesdorff Adam J 
Published: January 2020

Abstract
We report an improved kinetic colorimetric system for measuring lactate dehydrogenase activity in serum. In the system a tetrazolium salt, 2-p-iodophenyl-3-p-nitrophenyl-5-phenyl tetrazolium chloride, is used as the chromogenic indicator of dehydrogenase activity, with diaphorase serving as the electron transfer agent. All ingredients required for an assay are combined in a single dry reagent that is stable at room temperature. The method is 2.5 times as sensitive as the ultraviolet method of Wacker and has a dynamic range three times that of the ultraviolet method. Reducing substances in serum do not affect the results. Precision, range of linearity, and stability of reagent after reconstitution are excellent. Results for fresh sera correlated well with those obtained by the "A-Gent" ultraviolet method (Wacker method at 37°C) and with the SMA 12/60.
A Multi-Purpose Miniature Computer for Clinical Applications
Authors: Pardue Harry L , Parker Russell A , Gaw Henry 
Published: January 2020

Abstract
A low-cost miniature computer suitable for multipurpose applications is described. The computer combines digital and analog circuitry to provide a hybrid system that offers both economy and versatility. It uses a stored program to carry out data acquisition and processing operations automatically, and presents results on a numerical display in decimal format. Results are reported for molecular and atomic absorption spectroscopy and for the kinetic determination of enzymes.
Ultramicro Method for Determination of Iron in Serum with the Graphite Furnace
Authors: Olsen Eugene D , Jatlow Peter I , Fernandez Frank J , Kahn Herbert L 
Published: January 2020

Abstract
An ultramicro method is described for determining iron in 50 µl of serum. Hot trichloroacetic acid is used to remove protein and hemoglobin iron, and atomic absorption analysis of 10 µl of the supernatant fluid is carried out with use of a graphite furnace and a specially grooved graphite tube. Results correlate well with those obtained by a conventional flame atomic absorption method for iron that requires a 1-ml sample of serum. A standard graphite tube can be used if the trichloroacetic acid extract is first diluted with water, but we rejected this procedure because of the extra time and effort involved and because of the increased problem of artifactual contamination with iron. When serum was analyzed with no pretreatment, results were higher, probably because of hemoglobin iron present in serum, even serum with no visible hemolysis.
The Usefulness of Laboratory Tests in Health-Screening Programs
Authors: Sackett David L 
Published: January 2020

Abstract
I discuss pitfalls in laboratory-screening programs: regression toward the mean on repeated biochemical determinations; the problem of defining normalcy in the interpretation of laboratory test results; and a remarkable professional myopia in which clinical chemists have, with rare exception, failed to accept responsibility for evaluating whether the programs in which they are engaged are of benefit to patients.
Urinary Homogentisic Acid: Determination by Thin-Layer Chromatography
Authors: Feldman Jerome M , Bowman June 
Published: January 2020

Abstract
A new method is described for qualitative and quantitative determination of urinary homogentisic acid. The method involves extraction of urine with ethyl acetate, thin-layer chromatography of the extract on Silica Gel G, elution of the homogentisic acid into water, and color development with Folin’s phenol reagent. Absorbance is maximum at 750 nm and linear to a concentration of at least 5 mg of homogentisic acid per milliliter of urine. The method is highly specific for homogentisic acid; added gentisic acid, 3,4-dihydroxyphenylacetic acid, ascorbic acid, or L-3,4 dihydroxyphenylalanine do not interfere. The coefficient of variation "in-run" is 5.3%, "between-run" 6.8%. Using this method we have demonstrated a marked variation in day-to-day homogentisic acid excretion in a patient with alcaptonuria. This method, which offers some advantages over existing techniques, should be suitable for use in a clinical laboratory.
Gas-Chromatographic—Mass-Spectrometric Determination of Urinary Acid Profiles of Normal Young Adults on a Controlled Diet
Authors: Witten Thomas A , Levine Steven P , King Julia O , Markey Sanford P 
Published: January 2020

Abstract
Urinary acid metabolic profiles of 21 healthy young adults who were maintained on a palatable standard diet for three days have been studied by combined gas chromatography—mass spectrometry. Means and standard deviations of the excretion rates of individual, identified acids were obtained with the aid of internal standards.
Simultaneous Determination of Carbamazepine ("Tegretol") and Other Anticonvulsants in Human Plasma by Gas—Liquid Chromatography
Authors: Roger Jean-Claude , Rodgers George , Soo Alex 
Published: January 2020

Abstract
A gas chromatographic method in which an on-column reaction with a methylating reagent is used has been developed that permits the simultaneous determination of plasma concentrations of carbamazepine and of some other commonly co-administered anticonvulsant drugs, including phenobarbital, diphenylhydantoin, primidone, and mephenytoin. As little as 0.5 µg of any of these drugs can be determined per milliliter of plasma.
Fluorometric Determination of Plasma 11-Hydroxycorticosteroids. I. Rapid Procedure for Clinical Screening
Authors: Mejer Luis E , Blanchard Roberta C 
Published: January 2020

Abstract
A method proposed by Kitabchi and Kitchell [Anal. Biochem. 34, 529 (1970)] for the fluorometric determination of plasma 11-hydroxycorticosteroids has been modified. It is simplified by eliminating centrifugations, by processing all samples consecutively (rather than in small groups), by using disposable test tubes, and by prealkalinizing standards and blanks as well as plasma samples. Specificity and sensitivity are increased by measuring fluorescence at 520 nm, with an excitation wavelength of 470 nm. Effects of prealkalinization and time of fluorescence development on final cortisol values were studied. Large fluorescence increases are possible after 60 min of fluorescence development. Cortisol recoveries were not changed by the use of phase-separating filter paper nor were cortisol values altered by partial aging of the fluorescence reagent. Sensitivity, specificity, accuracy, and precision of the proposed method are reported.
Fluorometric Determination of Plasma 11-Hydroxycorticosteroids. II. Studies on the Specificity of the Method
Authors: Mejer Luis E , Blanchard Roberta C 
Published: January 2020

Abstract
We have investigated the specificity of the fluorometric method we proposed [Clin. Chem. 19, 710 (1973)] for plasma or serum 11-hydroxycorticosteroid determinations. The principal specific fluorogenic contaminants in the cortisol-containing extract of plasma, as detected by thin-layer chromatography and chemically, were triglycerides and total cholesterol. These contaminants contributed an average of 1.6 µg/dl to the total normal cortisol value. Fatty acids were also found, but did not fluoresce. Nonspecific serum fluorogens were quantitated at 1.3 ± 1.2 µg/dl. Cortisol, corticosterone, and fluorogenic contaminants represented an average of 62.0, 29.1, and 9.9%, respectively, of the total fluorometric plasma cortisol value obtained (expressed in terms of cortisol standard). A ratio of 8.3 ± 2.4 was found for cortisol/corticosterone when each component was determined in terms of its respective standard. Fluorescence scans of the plasma cortisol extract indicated cortisol to be the main component present, accompanied by minor fluorescent contaminants.
Fluorometric Fast Analyzer: Some Applications to Fluorescence Measurements in Clinical Chemistry
Authors: Tiffany T O , Watsky M B , Burtis C A , Thacker L H 
Published: January 2020

Abstract
A fluorometric Fast Analyzer has been developed, based on the GeMSAEC Fast Analyzer principle. Potential applications of a multiple-cuvet fluorometric analyzer are considered. A primary concern must be referencing enzyme activity assays and enzymic substrate analyses. Once adequate referencing techniques are developed, adaptation of analyses can proceed. The advantages of fluorescence procedures are sensitivity, availability of a variety of fluorogenic substrates, and potential perturbation of the excited state for direct physical measurements of interacting species. We describe the development of a direct kinetic assay, with use of 4-methylumbelliferyl phosphate, for human prostatic acid phosphatase; discuss assay of alkaline phosphatase activity with use of the same substrate; and consider the sensitivity of the analyzer as it relates to fluorescence tracer techniques and measurement of fluorescence polarization with the Fast Analyzer.
Measurement of Putrescine, Spermidine, and Spermine in Physiological Fluids by Use of an Amino Acid Analyzer
Authors: Marton Laurence J , Russell Diane H , Levy Carl C 
Published: January 2020

Abstract
Elevated polyamine concentrations in human urine and serum appear to be associated with the presence of many types of cancer. The automated amino acid analyzer lends itself to the rapid separation and measurement of these substances with little sample handling and excellent reproducibility. The ion-exchange resin used was Beckman’s PA-35 (strong sulfonic acid cation exchanger, copolymerization product of styrene-divinylbenzene). Amino acids are bound less strongly to the resin than are the polyamines, and can be removed by first eluting with a buffer of lower ionic strength. If sample injections are overlapped, one sample can be analyzed every hour. We have corroborated that increased concentrations of polyamines appear in the urine of patients with a variety of cancers. Additionally, we have shown increased amounts of polyamines in the serum of patients having a diagnosis of cancer.
Spectrophotometric Quantification of Glycine in Serum and Urine
Authors: Goodwin Jesse F , Stampwala Suresh 
Published: January 2020

Abstract
A method for quantitative determination of glycine in serum and urine, involving degradation to formaldehyde with chloramine-T and subsequent measurement by the Hantzsch reaction or chromotropic acid, has been evaluated and modified. The inhibitory effect of some physiological constituents on the analysis is pointed out. We recommend that samples be purified by passage through a column of ion-exchange resin before analysis. Results for urinary glycine obtained by a single-column amino acid analyzer system compare very favorably with those obtained by the proposed spectrophotometric method. Values for free and total glycine and for glycine/creatinine ratios in the urine of a group of infants are presented along with revised data on the concentration of free glycine in serum.
Gas Chromatography in Diagnostic Biochemistry of Abnormal Valine Metabolism
Authors: Tucker Hugh N , Molinary Samuel V 
Published: January 2020

Abstract
Amino acids in biological fluids can be rapidly and accurately quantitated by gas chromatography. Modification of existing gas-chromatographic techniques allow as little as 25 µl of biological fluids to be analyzed, compatible with sample sizes easily obtained in pediatric studies. Simplified diagnostic biochemical evaluation of a suspected aminoaciduria can be begun at birth, or shortly after. Normal amino acid patterns are compared with those found in a patient with abnormal amino acid concentrations. Gas chromatographic evidence is presented as a diagnostic aid in the evaluation of a patient with abnormal valine metabolism.
Ratiometric Triglyceride Analysis by Use of a Centrifugal Analyzer
Authors: Olson Arthur D , Brennan Richard L 
Published: January 2020

Abstract
We describe a simple, reliable, enzymatic method for triglyceride analysis, in which triolein is used as a standard. Use of a centrifugal analyzer greatly decreases required time and reagent cost. Results correlate well with those obtained by a standard automated continuous-flow method.
Values for Urinary Free Cortisol during Treatment with Amino-Glutethimide for Cushing’s Syndrome
Authors: Schmitt Karl W , Juselius Roger , Hanlon James , Steed David 
Published: January 2020

Abstract
Of the chemical tests used, we found that values for urinary free cortisol had the best clinical correlation and were the most sensitive indicator of cortisol secretion in a patient with Cushing’s syndrome who was treated with amino-glutethimide.