bluuebunny/crossref_metadata_2025_split huggingface dataset:
Methanolysis of the Intervertebral Disc
Authors: Chan David , Hull E Wayne , Fields Marvin , McNall Earl 
Published: January 2020

Abstract
Methanolysis of intervertebral disc samples at 60° was largely hydrolysis as shown by the absence of methylated derivatives on chromatograms of the reaction products. Extent of the reaction increased with acid strength; the products were the same. Maximum solubilization was about 80% and 50% for hyaline cartilage plate and nucleus pulposus samples, respectively. The results of aqueous acid (hydrolysis) for hyaline cartilage plate paralleled the methanolysis reaction. Nucleus pulposus samples did not show, in the aqueous system, a direct relation between acid strength and extent of reaction: 0.1 N acid solubilized more material than 1.0 N acid. Therefore, methanolysis and hydrolysis reactions may be used for differentiating tissue even though the basis of the "methylation blockade" of certain staining reactions is lost when performed at 60°.
Rapid Determination of Glutethimide (Doriden) by Gas-Liquid Chromatography
Authors: Winsten Seymour , Brody Daniel 
Published: January 2020

Abstract
A rapid simple gas liquid chromatographic technic has been developed for the identification and quantitation of glutethimide in biologic fluids. The method requires no evaporation of extracting fluid and will estimate glutethimide levels in the range of 1 mg./100 ml. or higher.
Quantitative Chromatographic Studies on Urinary Amino Acid Excretion
Authors: Geer Richard P , Hantman Richard K , Swett Cyrus V 
Published: January 2020

Abstract
Amino acid excretions of 82 individuals were quantitatively determined by ion-exchange chromatography. The results are expressed as µmoles amino acid per day, divided by milligrams α-amino acid nitrogen per day. This index is independent of age and provides a more useful method of representation than those presently employed in the literature.
An Automated Osmometer
Authors: Forman Donald T , Changus George C 
Published: January 2020

Abstract
A freezing-point apparatus, which measures osmotic pressure by determining freezing-point depression, was modified by incorporating a slowly rotating circular tray with space for 30 sample vials, and a sample pick-up device. The instrument is designed to automatically pick up a cuvet containing a 2-ml. specimen of serum, urine, spinal fluid, or any biologic fluid, and to cool, supercool, freeze, and record the osmolality of each sample. The pick-up device, consisting of a thermistor bridge null-point detector unit and 2 stirrers in an adapter unit, is automatically rinsed and dried after each determination. A sample reject system is incorporated in the event samples freeze improperly. A direct reading recorder is attached to the osmometer and gives a linear response in milliosmols per kilogram. The average time for individual sampling and recording of final data is 4 min. Thirty samples can be set up and run automatically with minimum direct supervision in 2 hr.
The reproducibility of this instrument showed an error not greater than ± 4 mosm./kg. The results of normal and abnormal physiologic osmolalities are reported and the effect of protein and carbohydrate on urine osmolality and specific gravity is examined.
Detection of Serum Alkaline Phosphatase Isoenzymes with Phenolphthalein Monophosphate Following Cellulose Acetate Electrophoresis
Authors: Romel William C , LaMancusa S J , DuFrene John K 
Published: January 2020

Abstract
Serum containing normal and abnormal levels of alkaline phosphatase activity were assayed for total enzyme activity, then fractionated by electrophoresis on cellulose acetate membranes for 20 min. The new substrate, phenolphthalein monophosphate, was employed to locate the isoenzymes on the cellulose acetate membranes and to measure their activity by eluting and scanning procedures. The sensitivity and precision of both technics are presented.
A Sequential Sampling System For Spectrophotometers
Authors: Annino Joseph S 
Published: January 2020

Abstract
A simple arrangement is described for filling, emptying, and rinsing an absorption cell without removing it from the spectrophotometer or opening the cell compartment. Specifications required for the cell, tubing, stopper, and valve are presented. Although the installation is described for a Beckman DB spectrophotometer, the device can be used with other instruments.
The Use of Carbon Monoxide and T-1824 for Determining Blood Volume
Authors: Myhre L G , Brown D K , Hall F G , Dill D B 
Published: January 2020

Abstract
Blood volume was determined with both T-1824 (Evans blue) and carbon monoxide (CO) for 2 young women, 2 young men, and 2 men ages 70 and 75. In the CO method a precise volume of CO was administered from a closed system, and the CO concentrations in blood were determined on the Van Slyke-Neill apparatus before and at the end of a 10-min. rebreathing period. The manometric technic is presented in detail and possible sources of errors are discussed. Comparisons were made during the spring in Indiana, in the hot desert, and at an altitude of 3800 m. Blood volume was taken as the sum of plasma volume (by T-1824 method) and red cell volume (by CO method); from these values body hematocrit was calculated. The ratios of body hematocrit to observed hematocrit ranged from 0.89 to 1.05 in 16 observations, with a median value of 0.93. In 12 of the 16, they ranged from 0.89 to 0.95, also with a median value of 0.93. Blood volumes determined by the CO method, using the 0.93 ratio, were within -1 to +4% of the blood volumes as determined above in 12 of 16 subjects. The other four differed by -7 to -13%.
Normal Serum Calcium Levels by Atomic Absorption Spectroscopy
Authors: Johnson J Robert K , Riechmann George C 
Published: January 2020

Abstract
Normal adult calcium levels were established with the atomic absorption spectrophotometric technic of Zettner and Seligson (1). Significant differences in calcium concentration were shown to exist between the sexes. Three commonly employed serum treatment technics were compared; two gave equivalent results.
Phenothiazine Interference and the Porter-Silber Reaction
Authors: Lupovitch Aaron 
Published: January 2020

Abstract
Phenothiazines interfere with the Porter-Silber reaction for urinary 17, 21-dihydroxy, 20-ketosteroids. The present study suggests that the interference is a depression or inhibition of the formation of the corticosteroid bisphenylhydrazone. Slight-to-marked aberration in the color of the acidified urine extract from dark yellow to orange or pink is the clue indicating that interference is present.
Preparation of Bilirubin-Diglucuronide Concentrates from Dog Bladder Bile
Authors: Talafant Edmund , Appelt Jirí 
Published: January 2020

Abstract
A method is described for the preparation of bile concentrate that contains a high proportion of bilirubin diglucuronide. The method involves acetone fractionation, precipitation as cinchonidine adsorbate, reprecipitation as lead salt, and finally conversion to a sodium salt by means of cationic exchange resin. The properties of the final concentrate are given.
Glucose in Serum and Cerebrospinal Fluid by Direct Application of a Glucose Oxidase Method
Authors: Ware Arnold G , Marbach Edward P 
Published: January 2020

Abstract
Glucose is measured directly in 0.02 ml. of serum or cerebrospinal fluid by reaction with glucose oxidase. The hydrogen peroxide produced reacts with iodide in the presence of a catalyst to form molecular iodine. The iodine color is proportional to the glucose and is measured photometrically. The reaction is carried out directly on serum following preincubation with molecular iodine and can be completed in 15 min. The results on normal serum average 8 mg./100 ml. lower than those obtained with the AutoAnalyzer reduction method. At a glucose concentration of 150 mg./100 ml., the procedure has a coefficient of variation of 1.4%. Recovery of added glucose averaged 98%. Hemolysis, lipemia, or icterus do not interfere.
Effect of Quality Control on Interlaboratory Performance
Authors: Rudy Jack L 
Published: January 2020

Abstract
For 7 months, serum samples reflecting high, normal, and low physiologic values were distributed to five laboratories for sodium, potassium, and calcium analyses. Following recalibration of instruments and required repairs, quality control programs were initiated and additional serum samples were analyzed. The results were collected and statistics calculated to determine improvement, if any, in accuracy and precision. Improvement was demonstrated in some cases.
An Evaluation of Hemoglobin Concentrations Obtained with Frozen Altered Drabkin’s Reagents
Authors: Walters Martha I 
Published: January 2020

Abstract
The effect of using completely frozen (decolorized) or partially frozen (faded) Drabkin’s reagents in measuring cyanmethemoglobin concentrations were evaluated. Since pigment produced by the decolorized reagent is oxyhemoglobin, falsely high values were obtained. However, pigment produced by the faded reagent is cyanmethemoglobin and no errors were introduced. The error introduced by using decolorized reagent for cyanmethemoglobin determinations depended upon the resolution of the instruments used for measuring absorbances. A simple procedure is described for measuring heme concentrations as reduced hemoglobin, and was applied to confirm cyanmethemoglobin values obtained in the various reagents.
Automated Procedure for Serum Aldolase Estimation
Authors: Kaldor J , Schiavone D Joan 
Published: January 2020

Abstract
An automated procedure for serum aldolase estimation is described. Using the same reagents, but different substrates, muscle and liver aldolase are differentiated. The procedure is based on the manual method of Bruns (1). A close correlation between manual and automated methods is shown.
A New Automated Determination of Xanthurenic Acid in Human Urine
Authors: Looyé A , Kwarts E W , Groen A 
Published: January 2020

Abstract
An automated determination for xanthurenic acid in urine was devised based upon its reaction with 2,6-dichloroquinonechlorimide. The separation of xanthurenic acid from interfering substances, such as urine chromogens and phenolic compounds other than xanthurenic acid, was performed by using Sephadex G-10. The effluents containing the xanthurenic acid were determined automatically. As a result of the high sensitivity of this procedure, concentration technics are unnecessary.
Interfering Ultraviolet-Absorbing Compounds as Sources of Error in Common Clinical Chemistry Tests
Authors: Warren Kenneth S , Scott Charles D 
Published: January 2020

Abstract
Fourteen spot tests and color reactions were selected for their potential applicability to the problem of identifying urinary components separated by a high-resolution analytical system. These tests were screened with an inventory of 74 biochemicals of current interest. The results of this testing program are given and reveal the lack of specificity inherent in many tests which are sometimes assumed to be free of interference.
An Automated Detection System for Most L-α-Amino Acids
Authors: Dyke K Van , Szustkiewicz C 
Published: January 2020

Abstract
An automated system for the determination of the L-α form of the majority of amino acids is presented. The method is based upon oxidative deamination of the amino acid coupled with oxidation of o-dianisidine by hydrogen peroxide. This procedure can be used comparatively for the determination of a mixture of L-α-amino acids or for the majority of separated L-α-amino acids (especially in conjunction with column separations from urine and blood which give falsely positive identification with ninhydrin detection). The stereospecific nature of the L-α-amino acid oxidase enables the investigator to quantitate the amount of L-α-amino acid in the presence of the D-α form. From an academic viewpoint, the extreme sensitivity and wide range of the detection system make it advantageous for the study of the enzyme itself. This automated method also may be employed to follow enzymatic reactions—e.g., those catalyzed by peptidases or racemases. The methodology is extremely convenient with good reagent stability and is much more sensitive than manometric technics.
Thin-Layer Chromatography of Anticonvulsant Drugs
Authors: Pippenger C E , Scott J E , Gillen H W 
Published: January 2020

Abstract
A rapid semiquantitative method for the determination of anticonvulsant drugs in blood and urine by thin-layer chromatography is described that is applicable in most laboratories. Utilization of SilicAR TLC-7GF with benzene:acetone (4:1), chloroform:acetone(9:1), and carbon tetrachloride:acetone(7:3) provides separation of Dilantin, phenobarbital, Mysoline, Phenylethylmalondiamide, Mesantoin, and Nirvanol.
Fluorometric Determination of Tyrosine
Authors: Ambrose John A , Sullivan Peggy , Ingerson Ann , Brown Ruby Lee 
Published: January 2020

Abstract
Modifications were made in the fluorometric method for the determination of serum tyrosine. An accurate and precise procedure was developed which did not involve the usual extraction with ethylene dichloride. The instability of the reaction mixture containing nitrosonaphthol, nitric acid, and sodium nitrite was corrected by the use of a phosphoric acid reagent.
Improved Nitromethane-Hyamine Method for the Chemical Determination of Nitrofurantoin in Whole Blood
Authors: Mattok G. L , McGilveray I.J , Charette Claude 
Published: January 2020

Abstract
The nitromethane-Hyamine method for assay of nitrofurantoin in whole blood has been improved: smaller volumes of blood (0.8 ml) are required, the sensitivity is greater (0.2 pg/mI), and the solution to be read is more stable than in the original method. The analysis detects 70 to 72% of 1 to 4 Ag of nitrofurantoin added per milliliter of whole blood. Blood concen-trations after the usual therapeutic peroral dose (100 mg) of nitrofurantoin are reported.
A Rapid Quantitative lon-Exchange Extraction for 2,8-Dioxyadenine
Authors: White Sandra H , Loken Michael R , Shields Charles E 
Published: January 2020

Abstract
A rapid quantitative method for the determination of 2,8-dioxyadenine in biological fluids has been developed and evaluated in which a two-step HCI elution from Dowex-50W is used. The standard curve has a slope of 0.999 0.0647, and recovery is essentially 100%. In contrast to the two-day col-umn chromatographic technique previously avail-able, this procedure permits numerous determina-tions in less than an hour, which makes it appro-priate as a rapid screening assay for 2,8•dioxyade-nine whenever large doses of adenine are admin-istered. A variation of this procedure may be used as a semiquantitative test for adenine.
Quantitative Cation-Exchange Chromatographic Analysis of Free Amino Acids in Human Amniotic Fluid Collected during Early Pregnancy
Authors: Saifer Abraham , A'Zary Edward , Valenti Carlo , Schneck Larry 
Published: January 2020

Abstract
The concentration of free amino acids in amniotic fluids, obtained from 27 normal mothers between the eighth and 22nd weeks of gestation, was determined by cation-exchange chromatography. Of the 29 free amino acids detected, three—γ-aminobutyric acid, ethanolamine, and homocarnosine— had not previously been found in amniotic fluid. The seven most common (in descending order) are alanine, glutamic acid-glutamine, lysine, proline, threonine, glycine, and valine. These seven comprise 70% of the total free amino acids present. All of the amino acids found in amniotic fluid have been found in serum and urine from fetuses and newborns and in the mother's urine. However, three of the amino acids found in amniotic fluid—ethanolamine, hydroxyproline, and homocarnosine—have not been reported to be present in serum from mothers.
Molecular Basis for a Simple, Specific Test for S Hemoglobin: the Murayama Test
Authors: Nalbandian Robert M , Henry Raymond L , Nichols Bruce M , Camp Frank R , Wolf Paul L 
Published: January 2020

Abstract
The Murayama test, a new, specific test for S hemoglobin, is based on the molecular mechanism of sickling for S hemoglobin proposed by Murayama [Clin. Chem. 14, 578 (1967)]. The test depends on a feature of molecular structure: hydrophobic bonds formed between interacting tetramers by the no. 6 valine, which is substituted for glutamic acid near the N-terminal end of each β S globin chain. Existence of these particular hydrophobic bonds is manifested in deoxygenated, concentrated hemolysates by reversible sol— gel transformations at 0° and 37°C. In such systems, demonstration of reversible, temperature-dependent sol—gel transformations (a negative temperature coefficient of gelation) is specific for S hemoglobin or the S structural variant, hemoglobin C (Harlem). The test is simple, has clear endpoints, will detect both homozygous and heterozygous S hemoglobin, and is specific. A practical approach is suggested to the precise identification of S and non-S sickling hemoglobins in the diagnostic laboratory. The close agreement between Murayama’s hypothesis for sickling in S hemoglobin and our results with 29 cases of S hemoglobin and 37 controls further support his views.
Labeling with Indocyanine Green of Serum Protein from Normal Persons and Patients with Acute Viral Hepatitis
Authors: Janecki Jerzy , Krawcyński Jerzy 
Published: January 2020

Abstract
Sera from normal persons and patients with acute viral hepatitis were mixed with indocyanine green (ICG), then fractionated on Sephadex G-200 columns. Alternate portions of the effluent were examined spectrophotometrically at 280 nm (for protein content) and at 800 nm (for ICG concentration). In most normal sera, three distinct ICG peaks were distinguished, the first and third corresponding exactly to the position of protein peaks, the second being most frequently shifted slightly toward heavier protein fractions. By graphic analysis, up to three additional masked peaks were usually detected in ICG curves. The individual fractions on ICG curves were numbered from I to VI, beginning with the fraction of greatest molecular weight. In the acute phase of viral hepatitis, the ICG curve was characteristically changed: fraction IV decreased significantly or even disappeared, and fraction I simultaneously increased. Fractions III and V also increased, but less. These changes in the ICG curves may result from interaction between serum proteins and liver cell proteins originating from damaged liver cells, an interaction leading to the formation of complexes of high molecular weight.
Variation in Urinary Creatinine Excretion and Its Relationship to Measurement of Urinary 17-Hydroxycorticosteroids
Authors: Cryer Philip E , Sode Jonas 
Published: January 2020

Abstract
Urinary creatinine excretion, measured in 96 24-h urine specimens collected from a single subject, was less variable (CV, 9.3%) than daily urine volume (CV, 20.7%). However, a small variation in measured creatinine excretion did exist, since the observed CV of 9.3% was not explicable either on the basis of analytical error (CV for replicate determinations, 1.1%) or of collection error. Thus, 24-h urinary creatinine excretion is not constant. On the other hand, demonstrated variation in creatinine excretion was small, and urinary 17-hydroxycorticosteroids could be validly expressed in mg/g of creatinine. In a given individual, biologic variation in 24-h creatinine excretion is negligible as compared with variation in 17-hydroxycorticosteroid excretion.
Measurement of Serum Lithium by Atomic Absorption Spectroscopy
Authors: Pybus John , Bowers George N 
Published: January 2020

Abstract
Lithium concentrations in the serum of patients undergoing therapy with lithium salts were measured by atomic absorption spectroscopy. Serum was diluted 10-fold with water. Physiological amounts of sodium and potassium were included in the blank and standard solutions because these cations enhance the lithium signal by 2%. Calcium, magnesium, bicarbonate, sulfate, and phosphate at the concentrations found in serum were without effect. Protein clogging of the triple-slot Boling burner was not observed. The relative standard deviation of within-run variability was 0.6% (n = 20 and x = 0.88 mEq/liter), and of daily precision, tested over a month, it was 2.5% (n = 30, x = 0.91 mEq/liter). Recovery of 1.00 mEq of lithium added per liter of serum ranged from 97 to 103%, averaging 99.8%.
Three Hydrolysis Methods for 17-Ketosteroid Sulfates Compared by Colorimetric and Gas—Liquid Chromatographic Analyses
Authors: Muehlbaecher C A , Smith E K 
Published: January 2020

Abstract
Three methods for cleavage of 17-ketosteroid sulfates were evaluated for their acceptability in the preparation of urine extracts for gas chromatography. Recovery after hydrolysis with hot hydrochloric acid was unacceptably low, but solvolysis with ethyl acetate—sulfuric acid or tetrahydrofuran—perchloric acid was equally efficient and satisfactory. The results obtained by four techniques were intercompared: radioactivity measurement, Zimmermann- or Allen-chromogen development, and gas chromatography.
Oxidation of Urinary 17-Oxogenic Steroids with Sodium Metaperiodate
Authors: Abernethy Maxwell H , Metcalf Mary G 
Published: January 2020

Abstract
Oxidation of urinary pregnane-17,20-diols (17-oxogenic steroids) by sodium metaperiodate is complete within 10 min at 55°C if the concentration of sodium metaperiodate at the end of the reaction exceeds 1.5 x 10-3M. A safe excess of sodium metaperiodate is present if assay samples, after incubation for 10 min at 55°C in 3 x 10-3M ethylene glycol, give a positive test with starch-iodide paper.
Automated Determination of Glucose in Serum or Plasma by a Direct o-Toluidine Procedure
Authors: Frings Christopher S , Ratliff Charles R , Dunn Ralph T 
Published: January 2020

Abstract
An automated determination of glucose with o-toluidine is described. Microquantities (0.04 ml) of plasma or serum are added directly to one reagent, without dialysis, to produce a green color that follows Beer’s law over a wide range of concentrations. This method compares favorably with a manual o-toluidine procedure.
Dopamine Transport in Human Blood
Authors: Bryson George , Bischoff Fritz 
Published: January 2020

Abstract
Distribution coefficients were determined for dopamine equilibrated between human blood cells and plasma or its constituents by direct fluorescent reading of this fluorophore recovered in the aqueous phase of a trichloroacetic acid separation. The fluorescence was activated at 280 nm and read at 320nm. Recovery of dopamine added to blood constituents was 98 to 102%. Dopamine concentrations in the equilibration phases ranged from 1-5µg/ml with 0.2mg of ascorbic acid as antioxidant. Water solubility accounts for approximately half of dopamine distribution in the red cell—plasma system. The other half is distributed between red cell and plasma proteins. Hemoglobin and Cohn fraction IV-4 show dopamine-binding effects. We trapped dopamine in red cell ghosts during hemolysis and demonstrated that it was released after reconditioning of the ghost membrane wall, thus indicating that the red cell wall is permeable to dopamine and that hemoglobin may act as a transport agent. The role of platelets and white cells in dopamine transport requires further study.
A Fluorometric Determination of Trypsin-Like Amidase Activity and Activity of Trypsin Inhibitors in Serum
Authors: Uete Tetsuo , Asahara Mineko , Tsuchikura Hiroko 
Published: January 2020

Abstract
The activity of crystalline trypsin and the trypsin-like amidase activity and the activity of trypsin inhibitors in serum were measured fluorometically, with α-benzoyl-L-arginine-β-naphthylamide (BANA) as substrate. The method is simpler and more sensitive than the colorimetric method based on the Bratton-Marshall reaction. Serum of pancreatectomized dogs hydrolyzed BANA at a significant rate, which suggests that serum amidases other than trypsin are active in this determination.