bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Carbon Cup Aging on Plasma Zinc Determination by Flameless Atomic Absorption Spectrometry
Authors: Chool Michael K , Todd John K , Boyd Nigel D 
Published: January 2020

Abstract
Determination of zinc in blood plasma by flameless atomic absorption spectrometry is discussed, with particular reference to the protocol required for the successful use of the Varian-Techtron Carbon Rod Atomizer. Cup aging is shown to be an important factor in limiting the precision of this analytical technique and ways of minimizing the problem are described. Matrix problems have also been encountered, which precluded the use of aqueous standard curves and the method of standard additions. We propose the use of plasma in preparing standard curves, the values for which are corrected for inherent plasma zinc, as a possible solution to the problem.
New, Simple Maltogenic Assay for Mechanized Determination of Alpha-Amylase Activity in Serum and Urine
Authors: Proelss Henning F , Wright Billy W 
Published: January 2020

Abstract
We report a new method for the mechanized determination of serum and urinary alpha-amylase by use of a continuous-flow system, based on the measurement of maltose formed by incubating the sample with amylodextrin at pH 7 and 40 °C. After dialysis, maltose is converted enzymatically to glucose, which is measured by Trinder's glucose oxidase—peroxidase method [J. Clin. Pathol. 22, 246 (1969)]. The reaction is linear for amylase activities up to 1400 Somogyi units/dl (2560 U/liter) and for maltose concentrations through 1500 mg/dl. No blank assay is required; consequently precision is improved and the automated system is simplified. Calibration with primary maltose standards increases accuracy and reliability. Common reducing substances in serum and urine do not interfere at their normal concentrations. There is a linear correlation between the results of this method and those of chromogenic and iodometric methods for normal and pathologic sera and urines. The chromogenic method yields significantly higher results and the iodometric method significantly lower results than this maltogenic method for elevated amylase activities. The normal range is 40-140 Somogyi units/dl (73-256 U/liter).
Fluorometric Assay of Serum γ-glutamyltransferase in Solution and on a Semi-Solid Surface
Authors: Rietz Bernd , Guilbault George G 
Published: January 2020

Abstract
We describe an enzymatic, fluorometric method for measuring the activity of serum γ-gIutamyItransferase (EC 2.3.2.2) in solution and on silicone rubber pads. N-γ-L-Glutamyl-α-naphthylamide in tris(hydroxymethyl)aminomethane buffer is used as substrate. In solution, measurements are performed at 37 °C with use of a reaction volume of 3.0 ml, in Pyrex cuvets. Measurements on silicone rubber pads are also made at 37 °C, after establishing a stable substrate film by lyophilizing the reagent for the γ-glutamyltransferase assay on the surface of the pads. Only 10-50 µl of buffered substrate and serum containing the enzyme to make a total volume of 60 µl are necessary for each assay. The rate of appearance of α-naphthylamine fluorescence (λex = 344 nm; λem = 445 nm), liberated from N-γ-L-glutamyl-α-naphthylamide by the enzymatic action of γ-glutamyltransferase, is measured and equated to its activity in serum. Calibration plots of the change in fluorescence per min vs. enzyme concentration for measurements in solution and on pads show a good proportionality in the range of 26.5-265 U/liter, and indicate the usefulness of these methods.
Nonchromatographic Radioimmunoassay of Plasma 11-Deoxycortisol, for Use in the Metyrapone Test, with Polyethylene Glycol as the Precipitant
Authors: Lee Lilian M Y , Schiller Harvey S 
Published: January 2020

Abstract
We have developed a simple, reliable radioimmunoassay for plasma 11-deoxycortisol. The method does not require chromatography but instead makes use of a simple extraction procedure which, in combination with the antibody characteristics, is highly specific for the metyrapone test. Polyethylene glycol was used to separate free and antibody-bound steroid. The smallest amount measurable is 15 pg (2.0 µg/ liter of plasma). The method is shown to be precise and accurate. Intra-assay precision of the method for two plasma pools was 26.7 ± 2.5 µg/ liter (CV = 9.4%) and 61.2 ± 3.7 µg/ liter (CV = 6.0%). The respective inter-assay precision was 27.0 ± 1.7 µg/ liter (CV = 6.3%) and 59.9 ± 2.3 µg/ liter (CV = 3.8%). The validity of the assay was further verified by evaluating the plasma 11-deoxycortisol response to metyrapone administration. The relative simplicity of the method and the commercial availability of all reagents, including antisera, makes this radioimmunoassay procedure practical for use in clinical laboratories.
Above-Normal Urinary Excretion of Urinary Ceramides in Farber's Disease, and Characterization of Their Components by High-Performance Liquid Chromatography
Authors: Iwamori Masao , Moser Hugo W 
Published: January 2020

Abstract
We compared the sphingolipid content of urine from a patient with Farber's disease with that of control urine. The ceramides were measured by high-performance liquid chromatography. The patient's urine contained 1.2 µg of ceramides per milligram of creatinine, more than 200-fold the normal amount. The urinary ceramides were isolated by high-performance liquid chromatography for further identification. They contained mainly nonhydroxy fatty acids and only a small quantity of those with 2-hydroxy fatty acids. This contrasts with the previously described composition of the patient's renal and cerebellar tissue. The fatty acid and long-chain base compositions of the urinary ceramides containing nonhydroxy fatty acids were nearly identical to those of the patient's kidney.
Fluorometry of Citrate in Serum, with Use of Citrate (pro-3S)-Lyase
Authors: Tomisek Arthur J , Winkler Edward M , Natelson Samuel 
Published: January 2020

Abstract
We describe a procedure for enzymatic assay of citrate in human serum. The citrate is degraded to acetate and oxaloacetate with citrate oxaloacetate-lyase (pro-3S-CH2 · COO- → acetate) (EC 4.1.3.6). Some oxaloacetate loses CO2 to form pyruvate. Addition of malate and lactate dehydrogenases (EC 1.1.1.37 and 1.1.1.27) permits determination of the oxaloacetate and pyruvate generated, and thus of the citrate concentration. The decrease in NADH concentration is measured fluorometrically. Results obtained for 30 consecutive human sera by this procedure were compared to the procedure in which the citrate is converted to pentabromoacetone. There was no statistically significant difference in values obtained by the two procedures. The range of values (mean ± 2 SD) found for sera from 25 blood donors by this procedure was 12.8-27.2 mg/liter (mean, 19.0 mg/ liter). Serum citrate as measured by both procedures during a glucose tolerance test was decreased from initial values under the influence of administered glucose (and endogenous insulin). Insulin concentrations were also measured during these glucose-tolerance tests. Citrate concentrations remain subnormal after the glucose and insulin concentrations return to their initial values. This accords with published reports.
Ultramicroscale Determination of Clinical Chemical Values for Blood during the First Four Days of Postnatal Life
Authors: deBaare Larissa , Lewis Jean , Sing Helen 
Published: January 2020

Abstract
Ultramicro procedures requiring 5-10 µl of serum or blood per analysis were used in determining blood constituents of healthy full-term newborns during the first four days of life. The resulting values appeared to be influenced by age, sex, and race. Values for total protein, albumin, urea nitrogen, and uric acid in serum decreased with time; serum inorganic phosphorus and whole-blood aldosaccharoses increased. Serum from females had higher values than that from males for total proteins, albumin, and inorganic phosphorus. The values for serum calcium and alkaline phosphatase were consistently higher in Negro than in white infants; values for uric acid were higher in the latter.
A More Sensitive Automated Method for Determination of Ornithine Carbamoyltransferase Activity in Human Serum
Authors: Clayson Kathleen J , Fine James S , Strandjord Paul E 
Published: January 2020

Abstract
Ornithine carbamoyltransferase (EC 2.1.3.3) activity is a sensitive, specific indicator of hepatocellular injury. This paper describes development of an improved automated procedure for measurement of this activity. Triethanolamine—ethylenedlaminetetraacetate is used as a buffer, and activity is determined by measuring the concentration of the product, citrulline. Kinetic studies have been performed to determine optimal pH and L-ornithine and carbamoyl phosphate concentrations. Recovery of citrulline was studied. The upper limit of normal obtained in a study of 106 blood-bank donors was 6 U/liter. The automated procedure developed as a result of these studies, in which optimal assay conditions are used, produces a threefold increase in sensitivity and permits use of a sample volume of 1 ml.
Electronic Timing of a High-Speed Immunonephelometric Continuous-Flow System
Authors: Lizana Jorge , Jansson Lennart , Hellsing Kristoffer 
Published: January 2020

Abstract
We describe a high-speed immunonephelometric continuous-flow system. The mechanical timing assembly and cams of the sampler were replaced by an external electronic control unit. Improved sampling precision, speeds of 2 to 900 samples per hour, and a wide variety of sample-to-wash ratios are the most important advantages of the unit. We analyzed albumin and fibrinogen at speeds of 150, 180, and 210 samples per hour. Carry-over studies showed that, in clinical practice, it should be possible to run the system at 150 samples per hour with an interaction of less than 5% and a precision (CV) of around 4%. Comparative studies with a previously described method, run at 60 samples per hour, showed correlation coefficients of 0.968 and 0.935 for albumin and fibrinogen, respectively. The electronic control unit can be used to increase speed and improve sampling precision of any continuous-flow system. An immunonephelometric system equipped with this device provided fast and reliable results, and required less antiserum than other systems described.
Improved Estimation of Urinary Myoglobulin by Counterimmunoelectrophoresis, as Compared with the Double Immunodiffusion Technique
Authors: Hibrawi Hazem , Blaker Robert G 
Published: January 2020

Abstract
We describe a simple, sensitive, and relatively inexpensive counterimmunoelectrophoretic technique for detection and estimation of myoglobin. The test can be completed within 90 min, compared with 12-48 h required by double immunodiffusion. With the counterimmunoelectrophoretic technique we could detect myoglobin in concentrations of 2-3 mg/liter, while the detection limit by double immunodiffusion was about 9 mg/liter.
Rapid Analysis for Theophylline in Serum by Use of High-Pressure Cation-Exchange Chromatography
Authors: Weinberger Miles , Chidsey Charles 
Published: January 2020

Abstract
We have developed a quantitative assay for serum theophylline by high-pressure cation-exchange chromatography. As little as 0.1-ml aliquots of serum were prepared for analysis simply by diluting them with a solution of the internal standard (8-chlorotheophylline). Theophylline and the internal standard were eluted in 17 and 27.5 min, respectively, and the peaks for them were distinct from those of other xanthines and uric acids. We encountered no interference when we used: (a) plasma obtained from blood anticoagulated with citrate; (b) hemolyzed, lipemic, or icteric serum; or (c) 52 samples from patients who were receiving various other medications. An analysis of calibration suggested that errors greater than ±2.6 mg/liter, a clinically acceptable range, were highly unlikely. Sensitivity was sufficient to identify less than 2.5 mg/liter. This assay was compared with the usual method involving solvent extraction and absorbance measurement in the ultraviolet and found to have similar accuracy, although it is easier, faster, requires less sample, and potentially is more specific.
Venous Serum, Capillary Serum, and Capillary Plasma Compared for Use in Determination of Lactate Dehydrogenase and Aspartate Aminotransferase Activities
Authors: Haymond Russell E , Knight Joseph A 
Published: January 2020

Abstract
Lactate dehydrogenase and aspartate aminotransferase activities in capillary serum or plasma were significantly greater than in simultaneously assayed venous serum, the greatest differences being between capillary and venous serum. Although some difference is attributable to tissue fluid contributions, platelets seem to account for most of it, with possible small contributions from leukocytes. Capillary tube size and type appear to be important factors. We recommend that when capillary blood is to be used for enzyme assay, it should be processed as plasma.
Electrophoretic Patterns of Alkaline Phosphatase Isoenzymes in Human Sera with Abnormally High Activity, and an Unusual Band Observed in Sera of Patients with Pancreatic Cancer
Authors: Cha Chung-Ja Mo , Mastrofrancesco Balduino , Cha Sungman , Randall Henry T 
Published: January 2020

Abstract
Alkaline phosphatase isoenzymes in sera were resolved by electrophoresis on cellulose acetate membranes into seven different bands (L1, B, Pl, L2, I1, I2, and Pa, in decreasing order of electrophoretic mobility). The slowest-moving band (Pa) was observed in the sera of 16 patients—15 with cancer of the pancreas and one with hemochromatosis. Sera of 50 other patients with malignant or benign diseases did not show the Pa band. The Pa band is more heat labile than is the liver isoenzyme (L1). Its behavior toward inhibitors (L-phenylalanine and L-homoarginine) is similar to that of L1. Sera containing the Pa band exhibit a diffuse band in the region where isoenzymes of intestinal origin migrate; however, its heat stability and stereospecific inhibition are different from those of intestinal isoenzymes in sera that show no Pa band.
Evaluation of the Beckman "System TR Enzyme Analyzer"
Authors: Passey Richard , Gillum Ronald L , Giles Mary Louise , Fuller John B 
Published: January 2020

Abstract
We evaluated 16 claims made by Beckman Instruments, Inc. for its Enzyme Analyzer (System TR), under a rigid written protocol for the Product Evaluation Subcommittee of the Standards Committee of the College of American Pathologists. We found the following to be within the company's specifications: (a) accuracy and precision of the temperature control; (b) accuracy and precision of the sample and reagent pipets; (c) instrument precision, both within-run and between-day; (d) carry-over from a sample with activity &gt; 1000 U/liter; (e) instrument-to-instrument variation; (f) analytical linearity; (g) analysis time; (h) correlation of the instrumentprinted answer with the activity calculated manually from a strip-chart recorder; (i) precision of the instrument's built-in electronic "standard"; (j) effectiveness of the over-range indicators; and (k) correlation between results of these enzyme assay methods and those for kinetic methods used in our laboratory. The instrument performed well.
New Colorimetric Reaction for End-Point, Continuous-Flow, and Kinetic Measurement of Urea
Authors: Jung David , Biggs Homer , Erikson John , Ledyard Peggy U 
Published: January 2020

Abstract
A reaction of urea, o-phthalaldehyde and N-(1-naphthyl)ethylenediamine is described for measurement of urea by manual, continuous-flow, and kinetic methods. The continuous-flow system requires 25 µl of sample; 40 samples can be analyzed per hour. The kinetic method requires no enzymes, has no lag phase, and has good sensitivity. A major advantage of the reaction is that it occurs at a temperature of 37 °C or lower. The results obtained by all three methods agree well with those for a continuous-flow procedure in which diacetyl is a reagent.
Improved Colorimetric Determination of Salicylic Acid and Its Metabolites in Urine
Authors: Farid Nagy A , Born Gordon S , Kessler Wayne V , Shaw S M , Lange W E 
Published: January 2020

Abstract
We describe an improvement in the Levy and Procknal method [J. Pharm. Sci. 57, 1330 (1968)] for determination of salicylic acid and its metabolites in urine. Salicylic acid and salicyluric acid are successively extracted from 1 or 2 ml of urine (acidified with HCl) by two 10-ml portions each of carbon tetrachloride and ethylene dichloride. The extracts of each solvent are shaken with 5 ml of ferric nitrate solution (a 10-fold dilution of 17 g of Fe(NO3)3·9H2O in 1 liter of 70 mmol/liter HNO3). The aqueous phases are centrifuged and their absorbances measured at 530 nm. For total salicylate, 3 ml of urine and 3 ml of HCl are heated in a partially evacuated serum vial at 100 °C for 16 h and then salicylic acid is assayed in the hydrolyzed sample. Recovery of a weighed oral dose of sodium salicylate in urine was 105.4%; it was 127.9% by the Levy and Procknal method for the same sample. The improved method is faster and more accurate.
Automated Elution Electrophoresis: A Potential Clinical Tool
Authors: Scott Charles D , Lee Norman E , Perkins Arthur W 
Published: January 2020

Abstract
An elution electrophoresis system in which a porous packed bed is used for separation and a flow photometer or colorimeter for continuous monitoring of the eluate may be capable of rapid, high-resolution analysis of serum proteins and other protein mixtures with very little manual labor. In a prototype of such a system we used a cooled separations column, 3 mm in diameter and 40 cm long, containing polyacrylamide beads. Samples are introduced, via a microsyringe, through a septum at the column midpoint. Typical analyses for serum proteins or serum isoenzymes require an electrophoresis time of about 30 min at 1200 V.
Development of a Multipurpose Optical System for Use with a Centrifugal Fast Analyzer
Authors: Burtis C A , Bostick W D , Johnson W F 
Published: January 2020

Abstract
A Centrifugal Fast Analyzer is basically a sophisticated photometric measuring device containing a multicuvet rotor as its major component. Several reactions are simultaneously initiated in the rotor, which is then rotated through a stationary optical monitor and the resulting signals acquired and processed by an on-line data system. With the miniature version of this analyzer, one has the option of directing the incident optical beam, via a fiber optical bundle, into the cuvets of the spinning rotor in either a 90° or a 180° orientation relative to the analyzer's photodetector. The combination of newly designed rotors and a flexible optical system having multiple configurations has provided a versatile system in which one can measure the transmittance, fluorescence, chemiluminescence, or light-scattering (either turbidimetrically or nephelometrically) properties of the ensuing reaction species, all with a single analyzer. This flexibility in choosing the optical mode in which a particular set of reactions is to be monitored provides the analyst with a powerful and versatile analytical tool for developing new methods for use in various clinical laboratory applications, including chemistry, toxicology, immunology, and hematology.
Application of Differential Light Scattering to the Latex Agglutination Assay for Rheumatoid Factor
Authors: Blume Philip , Greenberg Leonard J 
Published: January 2020

Abstract
When a suspension of particles is irradiated with a collimated beam of monochromatic polarized light of a wavelength close to the particle size and the intensity of the scattered light is measured as a function of angle, the scatter intensity is characterized by a series of relative maxima and minima. The nature of the signal depends on several significant variables that are characteristic of the particles. We have constructed a differential light scatter photometer and have applied the technique to analysis of rheumatoid factor by using latex particles coated with fraction II gamma-globulin. The results suggest that such a photometer may have potential applications in antigen-antibody assays based on the use of sensitized particles.
Potential for Clinical Use of the Analytical Laser Microprobe for Element Measurement
Authors: Glick David , Marich Kenneth W 
Published: January 2020

Abstract
Use of the laser microprobe for rapid emission spectroscopic analysis of elements in microscopic samples of biological material is described. The technique depends on vaporization of the microsample with a focused laser beam at a temperature that renders the vapor incandescent for spectrochemical analysis. Spectral line intensities are recorded photographically with densitometry of the negatives or photoelectrically. Current capability permits analysis of about 10-8 to 10-10 g of tissue, with detection limits of 10-12 to 10-15 g of element. Groups of elements can be simultaneously analyzed. Minimum sample preparation is required, and the analysis is done on the stage of a light microscope, usually on an air-dried sample on a plastic slide. We exemplify the technique in analysis of gold in cultured fibroblasts treated with gold salts and in human skin after treatment with gold salts for rheumatoid arthritis, in element changes in biopsies of transplanted human hearts, and in unique profiles of groups of elements in human cancer tissue.
Making Enzymatic Methods Optimum for Measuring Compounds with a Kinetic Analyzer
Authors: Atwood John G , DiCesare Joseph L 
Published: January 2020

Abstract
Kinetic enzymatic methods for analysis of substrates can be made optimum for a sensitive photometric analyzer by adjusting the activity of the triggering (catalyzing) enzyme so that the reaction rate is maximum at the time of measurement. At this optimum activity, the exponential time constant for exhaustion of substrate equals the time between triggering and rate measurement. The scale factor (defined as measured activity divided by sample concentration in the reaction mixture) is the same for all tests. Sensitivity to substrate concentration is predictable from instrumental absorbance uncertainty and molar absorptivity of the absorbing species. These predictions from Michaelis theory were verified experimentally for pyruvate and lactate triggered with lactate dehydrogenase, for glucose triggered with hexokinase, and for triglycerides triggered with glycerol kinase, the reaction rate being measured 30 s after triggering. Sensitivities of 1.5 x 10-7 mol/ liter were achieved. Serum diluted 1000-fold and analyzed for glucose gave a repeatability of 25 mg/liter with linearity to 4.0 g/liter. Samples diluted 300-fold and analyzed for triglycerides gave 30 mg/liter repeatability, with linearity to concentrations exceeding 3.0 g/liter.
Application of Electron Spin Resonance to Determination of Serum Drug Concentrations
Authors: Montgomery Mark R , Holtzman Jordan L , Leute Richard K 
Published: January 2020

Abstract
Displacement of spin-labeled drugs from drug-specific antibodies in human serum can be measured by use of electron spin resonance. This "spin immunoassay" has advantages of speed, simplicity, and small volume requirements over other standard techniques such as gas—liquid, liquid—liquid, or thin-layer chromatography. Unlike radioimmunoassay, there is no need to separate free and bound label and there are no radiation hazards. We present clinical and experimental data showing how this method can be applied to the routine determination of morphine and diphenylhydantoin concentrations in serum.