bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of Compounds of Biological Interest by Electron Spectroscopy
Authors: Hulett L D , Carison T A 
Published: January 2020

Abstract
Electron spectroscopy involves measuring the energies of electrons ejected when matter is irradiated with photons. One of the more powerful applications of electron spectroscopy is the determination of the binding energies of the inner shells of atoms with soft X-rays. The binding energies of the inner shells are characteristic of the element; thus, a means of qualitative analysis is provided. Quantitative analysis can be done also. In addition, use of high-resolution spectroscopy enables one to determine the oxidation state of each atom, because the binding energies will shift with chemical environment. For example, the K shell binding energy in nitrogen is about 10 V lower for an amine group than for a nitro group. This analysis can be used for all elements with atomic numbers higher than lithium. The advantages of electron spectroscopy for biological research, both for fundamental and in chemical applications, are discussed in general. Recent studies on t-RNA and its bases are given as specific examples of the applicability of the method.
Biogenic Amines in Normal and Abnormal Behavioral States
Authors: Bryson George 
Published: January 2020

Abstract
Involvement of the biogenic amines—acetylcholine, epinephrine, norepinephrine, dopamine, serotonin, and γ-aminobutyric acid—in behavioral states through neurotransmission is appraised. An accessory role is favored for acetylcholine because its distribution and function in the brain are less specific than those of norepinephrine or serotonin, which are concerned with REM and deep sleep, while epinephrine is concerned with brain stem activity in wakeful and (or) aggressive arousal. Decreased brain metabolism of norepinephrine and serotonin has been correlated with conditions favoring aggression. Norepinephrine and acetylcholine are implicated in neurochemical coding which regulates food and water intake. γ-Aminobutyric acid and other amino acids can facilitate or inhibit neural transactions. The precursor to dopamine alleviates Parkinsonian tremor. Aberrant catecholamine metabolism and structural differences in related psychotomimetic substances are considered in the etiology of schizophrenia, depression, and similar affective disorders. Other states of impaired behavior are also linked with altered biogenic amine chemistry.
Biological and Analytic Components of Variation in Long-Term Studies of Serum Constituents in Normal Subjects
Authors: Harris Eugene K , DeMets David L 
Published: January 2020

Abstract
Intra- and interindividual components of variation in ionized calcium among normal individuals have been estimated. The basic data were means of duplicate analyses of total serum calcium, total serum protein, and serum albumin from 68 normal subjects, 10-12 weekly samples per person. The McLean-Hastings equation was used to estimate [Ca2+]. Use of observed albumin/globulin ratios, instead of an assumed constant, had negligible effect on mean [Ca2+] or components of variation. The interindividual component of variation in [Ca2+] was found to be the same as that in total calcium: 3%. Average intraindividual variation (0.045-0.05 mmol/liter), appeared to be entirely attributable to analytical deviations in total protein and total calcium determinations. Thus, in the average normal individual, no physiologic variation in [Ca2+] could be detected. Results agreed with recent data on [Ca2+] measured by calcium ion-selective electrodes.
L-Benzylalanine as a Model Amino Acid for the Study of Accumulation Diseases
Authors: Grümer H-D , Hetland L B , Costantini M L 
Published: January 2020

Abstract
L-Benzylalanine, like phenylalanine, accumulates in vivo when fed to rats, leading to diminished uptake of a number of amino acids into brain without a corresponding change in serum. The similar effects of benzylalanine and phenylalanine on other brain amino acids in the experimental animal, as well as some similarity of the catabolism of these two amino acids, adds benzylalanine to the list of compounds that can simulate an accumulation disease.
Automated Liquid Chromatographic Determination of 5-Hydroxyindoleacetic Acid in Urine
Authors: Brown Harold H , Rhindress Meredith C , Griswold Robert E 
Published: January 2020

Abstract
Liquid column chromatography with automatic sample presentation makes it possible to automate some laborious procedures of the clinical chemistry laboratory. It is feasible accurately and automatically to determine a single substance in numerous specimens. To demonstrate the potential of this technique, we successfully adapted to commercially available equipment the Maickel and Miller fluorescent o-phthalaldehyde reaction with indole derivatives, for determining 5-hydroxyindoleacetic acid (5-HIAA) in urine. Automated cation-exchange chromatography combined with the o-phthalaldehyde reaction affords excellent specificity and sensitivity. Analysis time, including regeneration of the resin, is about 30 min per sample, and when the sample plate is loaded, the instrument runs unattended. Parallel determinations with a manual solvent extraction procedure give good correlation. Although the instrumentation is costly, adaptation of such determinations as 5-HIAA will justify wider use of this versatile tool.
Measurement of "Free" Thyroxine in Serum
Authors: Lee Norman D , Pileggi Vincent J 
Published: January 2020

Abstract
A dialysis method for determining "free" thyroxine in diluted serum is presented. The effect of a number of variables (pH, incubation time and temperature, buffer composition and concentration, protein concentration, and specimen dilution) was studied, and pertinent data are presented. Within-run precision (95% confidence limits) was ±10.6%; between-run precision was ±14.2%. Specimens from 84 healthy subjects were analyzed, and normal ranges are presented. The method has been used for five years, and has been found to be simple and suited to simultaneous analysis of large numbers of specimens.
Spectrophotofluorometric Determination of Porphyrins in Urine
Authors: Martinez Carolyn A , Mills Gordon C 
Published: January 2020

Abstract
A rapid procedure has been developed in which an anion-exchange resin and spectrophotofluorometry are used to determine total porphyrins in urine. After porphyrins are eluted from the resin with 3N HCl, their fluorescence at 646 nm is measured with an Aminco-Bowman Spectrophotofluorometer. About 10 min are required per analysis by a skilled technician. Added to urine specimens, 95.3 ± 4.9% of uroporphyrin and 94.7 ± 9.6% of coproporphyrin, were accounted for. Eighteen normal urine samples contained an average of 0.063 µmol of porphyrin per liter (range, 0.028-0.176 µmol/liter). The coefficient of variation, 2.9%, indicates the precision to be very satisfactory.
Profile of Sedatives and Tranquilizers in Serum, as Measured by Gas-Liquid Chromatography
Authors: Proelss Henning F , Lohmann Herman J 
Published: January 2020

Abstract
We describe here a rapid and comprehensive screening method for 40 commonly used sedatives and tranquilizers with use of gas-liquid chromatography. Barbiturates, nonbarbiturate sedatives, and tranquilizers of the phenothiazine, benzodiazepine, and dibenzazepine type can be both identified and measured in serum. A simple solvent extraction at different pH values, with subsequent solvent partition, effects a preliminary separation into acid, neutral, and basic drugs. The three fractions are separated on two standard 180-cm glass columns: acid and neutral drugs with the liquid phase XE-60 (3.5%) and basic drugs with the liquid phase OV-17(3%). Sera from more than 50 patients have been analyzed by this technique, and the concentrations of several sedatives and tranquilizers are reported.
Renal Tubular Transport of Amino Acids
Authors: Young John Atherton , Freedman Benedict Sol 
Published: January 2020

Abstract
Cushny in 1917 first remarked on the extensive amino acid reabsorption which occurs in the nephron. Although many workers since then have studied the nature and localization of the reabsorptive mechanism, progress has been slow because of the technical difficulties of micropuncture work. The bulk of filtered amino nitrogen is reabsorbed in the proximal tubule although the possibility of there being more distal reabsorptive (or secretory) sites cannot be excluded. It is also uncertain whether all segments of the proximal tubule contribute equally to the reabsorptive process. Amino acid reabsorption is an active process involving numerous illdefined steps, the first of which is binding to the brush borders. Renal amino acid transport mechanisms are of two kinds: the high-capacity low-specificity systems transport whole groups of amino acids—the acidic, basic, neutral, and imino-glycine groups—while the other, the low-capacity high-specificity systems, transport single or perhaps pairs of amino acids only.
Ion-Exchange Chromatography of Free Amino Acids in Human Intraocular Fluids
Authors: Durham Davis G , Dickinson Johanne C , Hamilton Paul B 
Published: January 2020

Abstract
Free amino acids were determined in human aqueous, vitreous, and subretinal fluid (50 to 100 µl) from individual eyes by using an ion-exchange chromatographic technique of increased sensitivity. The concentrations of amino acids in aqueous fluid from intraocular malignant melanomas were compared with those found for normal eyes, and some differences were observed. Other pathological conditions investigated were mongolism, intraocular hemangioma, uveitis, Sturge—Weber’s syndrome, and Marfan’s syndrome; only the latter two appeared to have a normal amino acid pattern. Vitreous and subretinal fluid each had a distinctive pattern, with the amino acid concentrations generally lower than in aqueous fluid, except for glutamine, which appeared to be of the same order of magnitude in all intraocular fluids and plasma. Postmortem and eye-bank aqueous fluids were also analyzed, and showed considerable variability from normal. The presence of an additional 28 unknown compounds was demonstrated in aqueous fluid.
Determination of Serum Lactic Dehydrogenase Isoenzymes by Use of the "Diagnostest" Cellulose Acetate Electrophoresis System
Authors: Di Giorgio John 
Published: January 2020

Abstract
A method is described for measuring serum lactic dehydrogenase isoenzymes by use of a commercial electrophoresis system. Six samples are simultaneously electrophoresed on cellulose acetate plates to separate the five isoenzymes, which are made visible by overlaying and incubating the electrophoresed plate with another plate saturated with lactate, phenazine methosulfate, and INT (a tetrazolium dye). The pattern is qualitatively assessed, or the plates are made transparent with dimethylsulfoxide— propanol and the isoenzymes measured densitometrically. The normal range for each isoenzyme, determined on 39 nonmedicated, nonfasting men and women, agrees with reported values. Duplicate plates are obtained for each serum analyzed. The entire procedure requires 2 h.
Gas Chromatographic Assay of Underivatized 5,5-Diphenylhydantoin (Dilantin) in Plasma Extracts
Authors: Sampson Dian , Harasymiv Irene , Hensley W J 
Published: January 2020

Abstract
A simple, rapid, and accurate method is described for determining diphenylhydantoin concentrations in plasma. An internal standard, primidone (primaclone), is added to 2 ml of acidified plasma, and primidone and diphenylhydantoin are extracted into chloroform. The extract, washed with hexane and concentrated, is injected into a gas chromatograph. Extraction and measurement of a single sample requires about 30 min, and as many as 40 samples can be assayed in a working day. Both therapeutic and overdose concentrations of diphenylhydantoin in plasma can be detected and measured. Nine other acidic drugs, added to plasma samples, did not interfere with the analysis.
A Simplified Assay for Porphyrins in Whole Blood
Authors: Heller Samuel R , Labbe Robert F , Nutter Janet 
Published: January 2020

Abstract
Recent investigations concerning the significance of porphyrins in erythrocytes indicate a need for a rapid quantitative assay, easily adaptable to routine clinical use. To fill this need, we have developed a simplified procedure for the measurement of porphyrins (essentially protoporphyrin) in whole blood. Blood is stirred with acetone—ethyl acetate and the porphyrins are extracted with formic acid—ether. The porphyrins are then extracted into HCl and measured spectrophotometrically at three wavelengths, a procedure that allows a corrected absorbance to be calculated, to minimize error caused by interfering substances. The assay requires little apparatus, is simple and dependable, and the results correlate well with those obtained by use of a more complex conventional procedure.
Electrophoresis of Plasma Lipoproteins on Gelatinized Cellulose Acetate
Authors: Vergani C , Rho G L , Vannotti M , Vecchi G 
Published: January 2020

Abstract
A method for electrophoretic separation of serum lipoproteins on gelatinized cellulose acetate is described, which does not involve any critical step, and allows repeatable results with a clear-cut separation of beta, pre-beta, alpha-lipoproteins, and chylomicrons. Many samples can be examined simultaneously on a large sheet and the electropherograms are ready to be examined or densitometrically scanned in 2 h.
Hepatitis-Associated Antigen (HAA). I. Quantitation by Electrophoresis in Antibody-Containing Agarose Gel by Use of a Primary Standard of Purified HAA
Authors: Boenisch Thomas , Katz Gerson 
Published: January 2020

Abstract
Hepatitis-associated antigen (HAA) has been isolated from pooled HAA positive human serum for use as a purified HAA primary standard and in production of antiserum in guinea pigs. These reagents were used in conjunction with electrophoresis in antibody-containing agarose gel, to simultaneously screen for and measure HAA. The smallest concentration of antigen that we could detect was 2 mg/100 ml of serum; the highest concentration of antigen encountered was 170 mg/100 ml. The method was compared with the Ouchterlony double diffusion and counterelectrophoresis techniques. Several antisera against HAA are compared with each other and their titers expressed in milligrams of HAA precipitated per milliliter of antiserum.
Use of Evacuated Collection Tubes for Routine Determination of Arterial Blood Gases and pH
Authors: Fleisher Martin , Schwartz Morton K 
Published: January 2020

Abstract
There is a well-recognized need for a reliable, convenient, and simple method for determining whole blood pH, PaCOaCO2, and PaOaO2. We have designed a specimen collection set that facilitates collection of the specimen and permits convenient and reliable analysis by the laboratory. Specimens are collected in newly designed "Vacutainer" tubes containing heparin and nitrogen gas. Without removing the Vacutainer stopper, the specimen may be anaerobically introduced into the analytical equipment through a unique aspirating needle. Atmospheric contamination of the specimen is eliminated.
Use of Automatic Digital Data Acquisition and On-Line Computer Analysis in High-Resolution Liquid Chromatography
Authors: Chilcote D D , Mrochek J E 
Published: January 2020

Abstract
A computer program for the acquisition and on-line analysis of data from a high-resolution liquid chromatograph is described. Emphasis is placed on the means of designing the computer program to overcome certain problems encountered in analyzing the data, mainly as a result of noise. The areas discussed include: detection of the beginning and end of the peak, location of the peak maximum, calculation of peak area, location of inflection points, and resolution of overlapping peaks. Analytical results obtained from the computer analysis of reference compounds separated by highresolution liquid chromatography are presented. These results are compared with those obtained by manual quantitation of the chromatogram to illustrate the usefulness of the small, on-line computer as a quantitative tool in liquid chromatography.
Clinical Chemistry: A Challenge for High-Purity Standards and Reagents
Authors: Zief M , Michelotti F W 
Published: January 2020

Abstract
The dynamic interplay between preparation, handling, containment, and analysis of ultrapure chemical standards and reagents for the clinical chemistry laboratory is described. Inorganic as well as organic standards are reviewed. The contamination problems associated with water, acids, and solvents in trace-element analysis are defined and resolved. In addition, less well-known sources of error in trace analysis are reviewed, as are the common contaminants in the clinical laboratory. It does little good to use a 99.99% primary standard with water of unknown quality in a heavily contaminated laboratory. Fortunately, recognition, definition, and solution of this problem is possible and should introduce new levels of precision and accuracy in the clinical chemistry laboratory.
A Single-Reagent Manual Method for Directly Determining Urea Nitrogen in Serum
Authors: Foster Lowell B , Hochholzer Jane M 
Published: January 2020

Abstract
A direct method is described, in which a single reagent is used without deproteinization, for measuring blood urea nitrogen (BUN) in serum. The reagent is a mixture of diacetylmonoxime, antipyrine (phenazone), and arsenic pentoxide in acid solution. Lipemia, bilirubin to 25 mg/100 ml, hemoglobin to lg/100 ml, and protein to 20g/100 ml do not affect the results. Beer’s law is followed at 460 nm for BUN concentrations as great as 100 mg/100 ml. The direct method compares favorably with a manual urease— Berthelot color method and with the diacetylmonoxime procedure as automated for the Technicon SMA 6/60. The method (CV, 6.7%) can be completed in less than 20 mm. The reagent is stable for at least two months.
Determination of Plasma α-Amino Nitrogen by Atomic Absorption Spectrophotometry
Authors: Hall Frank F , Schneider Barbara , Culp Thomas W , Ratliff Charles R 
Published: January 2020

Abstract
An uncomplicated, indirect method is described for the determination of α-amino nitrogen in plasma. Plasma is deproteinized with trichloroacetic acid and the protein-free filtrate is neutralized with alkali. The α-amino groups complex with and solubilize copper from insoluble copper phosphate. The solubilized copper, measured by atomic absorption spectrophotometry, is proportional to the amount of α-amino nitrogen present in the plasma.
Automated Hexokinase Procedure for Assaying Glucose in Urine, Serum, or Plasma
Authors: Yee Hugh Y 
Published: January 2020

Abstract
A colorimetric hexokinase method is described for measuring glucose in urine with the AutoAnalyzer. Pretreatment of the urine is not necessary. Sampling rate is 50/h, sample requirement 0.13 ml. Absorbance is measured at 505 nm; Beer's law is followed to 300mg/liter. Results obtained with this procedure and by one in which o-toluidine was used in combination with glucose oxidase were highly correlated (r = 0.998). Glucose concentrations in serum or plasma may be determined by diluting the sample 10-fold. Bilirubin in concentrations up to 200 mg/liter do not significantly interfere. With a dilutor, 20 µl of plasma or serum is diluted to 0.2 ml directly from a capillary collection tube after centrifugation. Thus, a convenient, sensitive method is available for assaying glucose concentrations in pediatric specimens.
Effect of Hemolysis on the Apparent Concentration of Insulin in Plasma
Authors: Cantrell Jerald W , Hochholzer Jane M , Frings Christopher S 
Published: January 2020

Abstract
The effect of hemolysis on the concentration of insulin in plasma was studied by a radioimmunoassay method. Plasma specimens with hemolysis have apparently lower insulin concentrations than plasma specimens without hemolysis, probably owing to the ability of red cell constituents to degrade insulin. The effects of hemolysis on the radioimmunoassay of insulin are quantitated, and the necessity of a properly collected sample for insulin assay is discussed.
Effect of Aging of Serum on Quantitation of Complement Component C3
Authors: Davis N C , West C D , Ho M 
Published: January 2020

Abstract
Concentrations of the third component of complement (C3, β1C globulin) in serum may vary considerably in patients with certain diseases. Its accurate measurement is therefore important medically. For some time it has been recognized that the C3 in serum stored at room temperature breaks down into two proteins, β1A and α2D. Monospecific antisera have been made to the three antigenic determinants of C3, designated A, B, and D. An anti-C3 supplied commercially is monospecific for the A determinant, which is shared by C3 and its breakdown product β1A. With C3 breakdown and formation of β1A, depletion of antibody to the A determinant is increased to 1.6 times the depletion by native C3. Therefore, the previous history of a serum can affect the "apparent" concentration of C3, with values spuriously increased to a variable degree, in serum that has been stored. The effect of time, temperature, and conditions of storage on this increase are discussed.
Inhibition of Leukocyte Acid Phosphatase by Heparin
Authors: DeChatelet Lawrence R , McCall Charles E , Cooper M Robert , Shirley Pamela S 
Published: January 2020

Abstract
Low concentrations of heparin (&lt;1 unit/ml) inhibit by 80% the activity of leukocyte acid phosphatase. Leukocyte β-glucuronidase is less sensitive to heparin, and alkaline phosphatase and lysozyme are unaffected. The possible inhibitory effects of heparin should be considered in all measurements of leukocyte enzymatic activities.
Identification of Serum Cholinesterase Fluoride Variants by Differential Inhibition in Tris and Phosphate Buffers
Authors: Garry Philip J , Owen George M , Lubin A Harold 
Published: January 2020

Abstract
We describe a useful technique to identify "fluoride-resistant" serum cholinesterase variants (E1uE1f and E1fE1f) by using the method of Garry to detect "atypical" variants and to measure serum cholinesterase activity [Clin. Chem. 17, 192 (1971)]. With butyrylthiocholine as substrate, sodium fluoride is used as a differential inhibitor in both Tris and phosphate buffer systems (50 mmol/liter, pH 7.4, 25°C). Fluoride inhibition values are plotted on two-dimensional graph paper, Tris plus sodium fluoride vs. phosphate plus sodium fluoride. Inhibition values for the "fluoride-resistant" and "atypical" variants are located in specific quadrants, which permits unequivocal identification of each variant. Examination of 836 Caucasian preschool children revealed a gene frequency of 0.0066 for the "fluoride" variant. No "fluoride-resistant" variants were found in 168 Negro preschool children examined.
Automated Fluorometric Procedure for Measurement of Creatine Phosphokinase Activity
Authors: Rokos J A S , Rosalki S B , Tarlow D 
Published: January 2020

Abstract
An automated procedure is described for measuring creatine phosphokinase activity (in serum, although the technique is adaptable) with the Technicon AutoAnalyzer. Creatine, formed by the action of the enzyme on phosphocreatine and adenosine diphosphate, is measured by the fluorescence of its reaction product with alkaline ninhydrin solution. Thirty determinations can be made per hour, and only 0.2 ml of sample is required.