bluuebunny/crossref_metadata_2025 huggingface dataset:
The Clinical Stability of Serum Cholinesterase Activity
Authors: Wetstone Howard J , LaMotta Rudolph V
Published: January 2020

Intra-individual variation of serum cholinesterase activity as determined in 82 normal adults studied 373 times over periods up to 5 years is found to be relatively low. The over-all coefficient of variation was 8.4, the linear correlation between the first and subsequent tests in the same person was r = .87 (first versus second test in 82 subjects) and r = .90 (first versus seventh test in 14 people). A decline of 0.66 U. from a single prior measurement when in normal health is significant at the .05 level. The clinical significance of the test is discussed.
Comparison of Two Current Colorimetric Procedures for Determination of Serum Glutamic Oxaloacetic Transaminase
Authors: Nakamura R M , Magsaysay R , Kunitake G M
Published: January 2020

A comparison of two colorimetric procedures for the determination of serum glutamic oxaloacetic acid (SGOT) showed that both the dinitrophenylhydrazine and diazonium salt colorimetric assay procedures have good precision and reproducibility acceptable to most clinical laboratories. Babson's diazonium salt procedure (3) definitely shows greater precision in the important borderline range of values than the dinitrophenylhydrazine method based on the Reitman-Frankel method (2). Advantages and disadvantages of both procedures are discussed.
An Automated p-Nitrophenylphosphate Serum Alkaline Phosphatase Procedure for the "Robot Chemist"
Authors: Morgenstern Stanley , Kessler Gerald , Auerbach Joseph , Flor Richard V , Klein Bernard
Published: January 2020

A new, precise, and accurate procedure is described for the automated determination of serum alkaline phosphatase on the Robot Chemist. The substrate, p-nitrophenyl-phosphate in 2-amino-2-methyl-1-propanol, offers the prime advantage of providing directly its own chromogen, p-nitrophenol, following enzyme action. Other advantages are the small sample volumes required and linear reaction rates. Correlations are presented between the manual procedure and those used with both the Technicon Auto-Analyzer and the Robot Chemist.
A Direct Photometric Method for Chloride in Biological Fluids, Employing Mercuric Thiocyanate and Perchloric Acid
Authors: Hamilton Robert Houston
Published: January 2020

The reagent described is 5.5 M in perchloric acid and 3.3 M in urea. It contains ferric ions, mercuric thiocyanate, mercuric ions (from mercuric perchlorate), and mercuric chloride. Serum dissolves directly in this reagent to yield a clear, reddish solution.

When chloride ions are added, they combine first with the free mercuric ions, and then with some of the mercuric ions from the mercuric thiocyanate. Liberated thiocyanate combines with ferric ions to yield red ferric thiocyanate. The color is much more intense in the presence of strong perchloric acid than in other aqueous acid mixtures, Its intensity can be regulated at will by changing the concentration of the ferric iron. The presence of mercuric chloride in the reagent improves linearity between absorbance and chloride concentration.

After the total absorbance is determined, compensation for absorbance by other substances is secured by adding mercuric ions to the photometer tube to reverse the color-producing reaction of chloride, reading the residual absorbance, and subtracting it from the total absorbance, to give a net absorbance produced by chloride alone.
Polyacrylamide Gel Electrophoresis of Spinal-Fluid Proteins
Authors: Evans John H , Quick Donald T
Published: January 2020

Twenty-three control samples of CSF were analyzed by vertical column electrophoresis on acrylamide gel. Quantitation results using a microdensitometer are presented. The normal protein pattern shows 15 constant bands which coincide in mobility and in many cases in staining pattern with serum proteins. The haptoglobin peaks, except for the band of the 1-1 type and the leading band of the 2-1 type were not seen in control fluids.
The Heptacarboxylic Porphyrin of Various Types of Porphyria and the Melting-Point Curve of Methyl Esters of the I and III Isomers
Authors: Chu T C , Chu Edith Ju-Hwa
Published: January 2020

The heptacarboxylic porphyrin (hepta) isolated from different types of porphyric urine samples contains different proportions of the isomers I and III. These were separated chromatographically. The hepta in congenital porphyria was found to contain 65% of Type I isomer and 35% of Type III; that in acute intermittent porphyria, 70-80% III and 20-30% I; and that in porphyria cutanea tarda, 80-90% III. Several other cases including 1 of coproporphyria, 1 of South African genetic porphyria, 1 of Bantu porphyria, 4 of hexachlorobenzene poisoning in Turkish individuals were also examined. From the X-ray diffraction pattern and long-column chromatography, the Hepta III prepared either from decarboxylation of Uroporphyrin III or by condensation of porphobilinogen revealed a more complex configuration than that isolated from porphyric materials. The natural hepta might be dominated by one of the four possible isomers of the III series.

A melting-point composition curve of methyl esters of Hepta I and III was constructed, and its applicability was tested. The identity of the hepta isolated in porphyria cutanea tarda with "208" and "pseudouro" porphyrins is discussed, and the name "cutano-porphyrin" suggested.
Elevation of Serum Protein-Bound Carbohydrates and Haptoglobin in Schizophrenia
Authors: Seal Ulysses S , Eist Harold
Published: January 2020

The mean concentration of each of the serum protein-bound carbohydrates (hexose, hexosamine, fucose, and sialic acid) was significantly elevated in a group of 60 male schizophrenic patients. The total serum protein was elevated, ceruloplasmin was normal, and C-reactive protein was absent. Serum haptoglobin was significantly elevated. The distribution of haptoglobin types was normal. Haptoglobin concentration variation was significantly correlated with each of the carbohydrates and, to a lesser degree, with ceruloplasmin. In a group of 13 patients with normal erythrocyte sedimentation rate, the fibrinogen and haptoglobin concentrations were significantly elevated. There was no correlation between haptoglobin and fibrinogen concentrations in this group.
The Automated Determination of Serum Uric Acid
Authors: Morgenstern Stanley , Flor Richard V , Kaufman James H , Klein Bernard
Published: January 2020

An automated procedure is presented for the enzymatic determination of serum uric acid on both the AutoAnalyzer and the Robot Chemist. The procedure measures as the neocuproine complex, the difference in the amount of Cu+ formed by reaction of a Cu++-alkanolamine buffered solution with serum uric acid under precisely controlled conditions before and after uricase treatment of the serum. The difference is proportional to the true serum uric acid content. The elements contributing to the enzymatic reaction, the colorimetric reaction, and the elimination of interferences were investigated. Comparison of serum uric acid values obtained by this method with those obtained by ultraviolet spectrophotometry show very good agreement.
A Modified Automated Ferricyanide-Phosphomolybdic Acid Procedure for Serum or Plasma Glucose
Authors: Klein Bernard , Morgenstern Stanley , Kaufman James H
Published: January 2020

Glucose in serum and plasma was determined by the automated ferricyanide-phosphomolybdate reaction, with modifications of both the flow system and reagents to adapt the procedure for use with the AutoAnalyzer. The modified method was shown to be precise and sensitive.
Colorimetric Determination of Serum Guanase Activity
Authors: Caraway Wendell T
Published: January 2020

A colorimetric method for the determination of serum guanase has been developed whereby ammonia, formed by the deteramination of guanine, is measured by the phenatehypochlorite reaction. Variations in substrate concentration, time of incubation, pH, temperature, and concentration of enzyme have been investigated with respect to enzyme activity. The determination of serum guanase appears to be useful in the differential diagnosis of jaundice.
Quantitative Analysis of Urinary 17-Oxogenic Steroids Using Sodium Metaperiodate Oxidation
Authors: Mefcalf Mary G
Published: January 2020

At 550° the oxidation of pregnane-17, 20-diols (17- oxogenic steroids) to 17-oxosteroids with sodium metaperiodate is complete within 10 mm. The yield of 17-oxosteroids is not affected by light or pH's between 4.6 and 7.0. The 17-oxgenic steroids may be oxidized in the presence of glucose provided that additional sodium metaperiodate, equivalent in amount to or in excess of the glucose, is used for oxidation.
The Automated Determination of NAD-Coupled Enzymes
Authors: Morgenstern Stanley , Flor Richard , Kessler, Gerald , Klein Bernard
Published: January 2020

A precise automated procedure developed for determination of serum lactate dehydrogenase, using the Robot Chemist, measures absorbance of a cuprous-neo-cuproine complex formed by coupled reduction of the cupric-neocuproine reagent with enzymatically generated reduced nicotinamide adenine dinucleotide. Activity values obtained by this method, by the identical automated colorimetric method on the AutoAnalyzer, and by an automated spectrophotometric (34O-mµ) procedure show excellent agreement.
Automated Determination of Acid Phosphatase
Authors: Klein Bernard , Auerbach Joseph
Published: January 2020

α-Naphthylphosphate is a selective substrate for the differentiation of prostatic acid phosphatase from erythrocytic acid phosphatase in human serum; its comparative specificity for prostatic enzyme is demonstrated by inhibition studies and by assay of mixtures of both enzymes in serum.
Automatic Estimation of Urea Using Urease and Alkaline Phenol
Authors: Wilson B W
Published: January 2020

A method for the automated determination of urea in plasma and urine, using urease and alkaline phenol, proved to have the advantages of speed and precision when compared with a manual method of the diffusion type. The mean percentage difference between results of the two methods did not differ from zero at the 1% level of significance when examined by the † test.
An Automated Colorimetric (Tetrazolium Salt) Assay for Serum Lactate Dehydrogenase
Authors: Capps Rodney D , Batsakis John G , Briere Russell O , Calam Roger R L
Published: January 2020

The adaptation of a tetrazolium salt assay for serum lactate dehydrogenase to fullautomation is described. The tetrazolium salt, INT, (2-p-iodophenyl-3-p-nitrophenyl-5-phenyl tetrazolium chloride) serves as the chromogenic indicator of the enzyme activity. Phenazine methosulfate serves as an intermediate electron carrier.

Estimation requires only 5 min. of incubation, and assays may be run at the rate of 60/hr. Comparison against the manual version of the assay with respect to normal and abnormal serum activity levels is excellent.
Assay of Urinary Porphyrins
Authors: Fernandez Alberto A , Henry Richard J , Goldenberg Harry
Published: January 2020

Previous authors have reported ranges of normal coproporphyrin excretion values which differ by several hundred per cent. The present study was undertaken to determine whether the scatter of normal values is a result of differences in analytical methodology. It is shown that the values obtained for copro-and uroporphyrin are the same whether urine extracts are assayed by spectrophotometry or fluorometry. Equivalent results are also obtained with solvent extraction and alumina adsorption technics. The coproporphyrin range for our normal adult population (0-161 µg./day) is intermediate between the literature values, while the uroporphyrin range (0-26 µg./day) is compatible with the reports of most workers.

An improved solvent extraction method for urinary porphyrins is presented in which n-butanol is used to isolate uroporphyrin after removal of the coproporphyrin fraction.
A Slide Rule for Time Conversion for Bromsulphalein (BSP) Retention Studies
Authors: Gindler E Melvin
Published: January 2020

In blood plasma, the concentration of injected Bromsulphalein is indicated by x at any time, t. The two quantities are related by the first-order equation In x = kt (k is aconstant). A specialized log-log slide rule has been developed to permit the rapid direct calculation of x at some value of t, when the value of x at some other time is known.
A Gas Chromatographic Method for the Determination of Lactic Acid in Blood
Authors: Savory John , Kaplan Alex
Published: January 2020

A method for the determination of lactic acid concentration in blood by gas chroma tography is described. Lactic acid in a protein-free filtrate is oxidized by ceric sulfate to acetaldehyde. The latter compound is introduced into the gas chroma tographic column by vapor phase injection, and is quantitatively measured within 3 min. The method is specific, precise, and not affected by compounds that may interfere with the determination of lactic acid by colorimetric or enzymatic methods.

A method for preserving blood samples up to 24 hr. without change in lactic acid concentration is also described.
A Simple Method for Extraction and Quantitation of 14C-Labeled Compounds from Blood
Authors: Marymont Jesse H , London Morris
Published: January 2020

This note describes a simple heat clot-extraction procedure for separation of water soluble 14C-labeled compounds of low molecular weight from serum-in a form sufficiently pure to enumerate in a gas-flow counter. Data obtained with glucose-1- 14C and uric acid-1-14C are presented. Similar results have been obtained with 14C-labeled galactose, allantoin, tyrosine, phenylalanine, and leucine.
Microtitration of Free Fatty Acids in Plasma
Authors: Goss J E , Lein Allen
Published: January 2020

A method for determination of free fatty acids in plasma has been developed which employs a modification of Dole's extraction procedure and involves a 1-phase system for titration rather than the 2-phase system most commonly used.
A Method for the Rapid Detection of Acute Iron Toxicity
Authors: Fischer David S
Published: January 2020

In acute iron poisoning, it is necessary for rational management to know whether the plasma iron exceeds the transferrin-binding capacity. A method for the rapid determination of iron in plasma is described whereby this essential information may be obtained in a few minutes. This test will help to differentiate simple iron ingestion from acute iron toxicity so the clinician may have a firmer basis upon which to decide whether chelate therapy is indicated.
Design and Operation of an Expanded System of Quality Control
Authors: Sax Sylvan M , Dorman Lakeles , Libenson David D , Moore John J
Published: January 2020

A functioning system of quality control, utilizing three types of control materials, is described. Analytic results obtained on control specimens are processed by computer to give a rapid indication of over-all accuracy and precision, technician performance, and need for restandardizing or trouble-shooting individual tests.
Serum Magnesium Concentration in Schizophrenia and Epilepsy
Authors: Seal Ulysses S , Eist Harold
Published: January 2020

Serum magnesium concentration values were determined on groups of normal, schizophrenic, and epileptic patients. The magnesium levels in all the groups were essentially identical and no single value was outside the limits of normal as defined by the mean ± 3 S.D.
Applications of Computer Produced Frequency Distribution Curves
Authors: Ressler N , Whitlock L S
Published: January 2020

Applications to quality control of a laboratory's own individual frequency distribution curves are described. The method has recently become feasible for routine use, since the curves can now be compiled automatically by means of an electronic data-processing system. Applications described include verification of the validity of results generated by a given method in terms of the frequency distributions obtained for each type of diagnostic classification, and the determination of the constancy of these distributions. The relative value of different test methods can be compared by the success which is achieved in distinguishing diagnostic classifications (as measured by the overlaps of different frequency distribution curves). Individual frequency distributions can also be used to determine the precision required for given test, in order to avoid any loss in the discrimination which can be achieved.
Clinical Chemistry in Rural Laboratories
Authors: Reynolds Moira Davison
Published: January 2020

Questionnaires dealing with the practice of clinical chemistry in their laboratories were sent to 172 selected hospitals with a bed capacity of less than 70, all in the United States and all 50 miles or more from any large hospital or medical center. Replies from 84 indicated that in the majority of the laboratories the actual work is done by individuals who have had college training and/or many years of experience. Most of the laboratories are adequately equipped to do the common clinical chemical assays whose usefulness might diminish if time were lost in transporting specimens elsewhere.
The Use of Ultraviolet Irradiation in the Estimation of Retinol (Vitamin A Alcohol) and Its Derivatives
Authors: Sherman Burton S
Published: January 2020

Quantitative studies on the estimation of retinol (Vitamin A alcohol) and its derivatives retinoic acid, retinal, retinyl acetate, and retinyl palmitate in dilute solution using the method of destruction by ultraviolet irradiation, showed that retinoic acid in organic solvents required a period of irradiation of from 2.5 to 8 times as long for destruction as did the other forms of the vitamin. This fact should be taken into consideration in any attempt to apply the method of Bessey et al. (1) for the analysis of retinoic acid in biologic material. Furthermore, standard solutions of retinoic acid in organic solvents are more stable after storage in the dark than are the other derivatives of the vitamin.
An Evaluation of Turbidimetric Technics for Estimation of plasma Fibrinogen
Authors: Goodwin Jesse F
Published: January 2020

Studies on precipitation and turbidimetric methods for fibrinogen determination employing Na2SO3, Na2SO4, (NH4) 2S04 and a mixture of phosphate salts are presented. Optimal reaction conditions for these technics have been verified. The amounts of plasma fibrinogen precipitated by the sulfite and phosphate methods are in closer agreement than either are with values obtained by the (NH4)2S04 and Na2SO4 precipitation technics. It has been determined that the degree of turbidity produced by salt fractionation is not a reliable index of the amount of fibrinogen present. The measurement of fibrinogen concentration of turbidity produced by the various fractionation agents does not appear to be precise enough for the quantitative measurement of this protein.
Measurement of DNA and RNA in Human Peripheral Blood Lymphocytes
Authors: Glen A C A
Published: January 2020

A method is described, modified from a published technic, for obtaining lymphocytes from human peripheral blood. The cell preparations containing greater than 90% lymphocytes were analyzed for their DNA and RNA content, using a modified Schmidt-Thannhauser procedure. The peripheral blood lymphocytes of 40 normal adults were examined, and normal values established for the 2 compounds. The mean lymphocyte DNA was 0.73 pg DNA phosphorus per million cells, and the mean lymphocyte RNA was 0.19 pg RNA phosphorus per million cells. These values are consistent with results published for human leukocytes. The ratio RNA phosphorus:DNA phosphorus is proposed as a reliable index of changes in the RNA content of the blood lymphocytes.
Interference by Formaldehydogenic Drugs in the Quantitative Determination of Urinary Hydroxyindoleacetic Acid
Authors: Shils Maurice E
Published: January 2020

The administration of methenamine mandelate (Mandelamine) to normal individuals and patients with carcinoid resulted in a marked reduction in apparent urinary hydroxyindoleacetic acid (HIAA) as determined by the quantitative nitroso-naphthol method. Mandelamine, methenamine, and formaldehyde inhibited the normal color development in vitro. The interfering reaction is dependent on an acid pH and is not reversed by raising the pH. It is suggested that formaldehyde is the active substance and the role of mandelamine and methenamine is that of a precursor of this substance in acid solution. Chloride and sulfate ions, per se, caused a definite but limited interference with the color reaction. Under the conditions of this study, mandelamine did not prevent detection of elevated urinary HIAA by the qualitative test for HIAA.
Optimum Conditions for the Reaction Between Uric and Phosphotungstic Acids in the Presence of Glycerol-Silicate Reagent, Including a Proposed Modification of the Archibald Method
Authors: Kanter Saul L
Published: January 2020

By controlling the alkalinity and the amount of phosphotungstic acid (PTA), turbidity and gelling in the final colored solution obtained in the reaction between uric acid and PTA in the presence of sodium glycerol silicate (NaGS) can be eliminated without using antiturbidity reagents. The optimum range of alkalinity is 0.55-0.76 mEq. of excess alkali in a total volume of 7.75 ml. A modification of the Archibald (1) method is proposed to assure optimum color development between uric acid and PTA-whether the uric acid is in an acidic protein-free filtrate or in a practically neutral aqueous standard solution.
Methanolysis of the Intervertebral Disc
Authors: Chan David , Hull E Wayne , Fields Marvin , McNall Earl
Published: January 2020

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

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.
Automated Atomic Absorption Spectrophotometry
Authors: Klein Bernard , Kaufman James H , Oklander Morris
Published: January 2020

The flow system developed for the determination of serum calcium by automated atomic absorption spectrophotometry (AAS) was adapted to the determination of serum magnesium. A comparison of the results of analyses by the present procedure and by an automated fluorometric procedure on identical serum specimens shows excellent agreement.
Quantitative Chromatographic Studies on Urinary Amino Acid Excretion
Authors: Geer Richard P , Hantman Richard K , Swett Cyrus V
Published: January 2020

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

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

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

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

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

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

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

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

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

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.
Fractionation of 17-Ketogenic Steroids by Solvent Partition
Authors: Whigham William R
Published: January 2020

A simple method of fractionating 17-ketogenic steroids by solvent partition is described. It was applied to specimens from 20 hospitalized patients with no apparent adrenal disorder and to 5 patients before and after oral Metopirone* treatment.
An Evaluation of Hemoglobin Concentrations Obtained with Frozen Altered Drabkin’s Reagents
Authors: Walters Martha I
Published: January 2020

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

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

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.
Determination of D-Xylose in Urine for the D-Xylose Absorption Test
Authors: Harris Alvin L
Published: January 2020

A method is described for the determination of D-xylose in urine which is based on the specific absorptivity of the pentose o-toluidine complex. Quantitation of xylose can be made in the presence of a hexose.
Interfering Ultraviolet-Absorbing Compounds as Sources of Error in Common Clinical Chemistry Tests
Authors: Warren Kenneth S , Scott Charles D
Published: January 2020

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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.
A Rapid Enzymatic Method for Estimating Ethanol in Body Fluids
Authors: Jones Donald , Gerber Louis P , Drell William
Published: January 2020

Alcohol dehydrogenase is a sensitive and selective reagent for the rapid, simple estimation of ethanol in body fluids. Serum need not be first deproteinized, and losses encountered in distillation procedures are precluded. The difference between the absorbance (at 340 nm) of sample and reagent blank gives the ethanol content of the specimen directly after a 5 to 10 min reaction. The standard deviation of the method is 3.6 µg/100 ml and the coefficient of variation is 1.8%. Recovery of ethanol is best by the present method, as compared with gas chromatography or distillation-dichromate oxidation, for alcohol concentrations of less than 0.1 g/100 ml
Rapid Glucose Oxidase-Peroxidase Ultramicro Method for Determination of Blood Glucose
Authors: Lenz Paul H , Passannante Anthony J
Published: January 2020

A rapid, convenient, and easy ultramicro modification of the glucose oxi-dase-peroxidase method for determining blood glucose is described. The reagent mixture is prepared by mixing phosphate buffer (pH 5.0) with lyophilized enzyme-chromogen (o-dianisidine). To this is added 20 µl of plasma or serum. After 15 min at room temperature the reaction is stopped, and the reaction mixture cleared, by adding 4M HCI. Absorbance is read at 400 nm vs. a reagent blank or, preferably, against a reagent blank containing serum or plasma. The individual (prepackaged) reagents are stable for at least 10 months; the reagent mixture and the color of the acidified reaction product are stable for more than 5 h. Protein precipitation, apparently un-necessary, has been eliminated. Absorbancies obtained by this method are linear for glucose concentrations as great as 300 mg/100 ml. Heparin, Parasepts, and benzoic acid do not inhibit the reaction.