bluuebunny/crossref_metadata_2025 huggingface dataset:
G4Killer web application: a tool to design G-quadruplex mutations
Authors: Brazda Vaclav , Kolomaznik Jan , Mergny Jean-Louis , Stastny Jiri
Published: January 2020

Motivation

G-quadruplexes (G4) are important regulatory non-B DNA structures with therapeutic potential. A tool for rational design of mutations leading to decreased propensity for G4 formation should be useful in studying G4 functions. Although tools exist for G4 prediction, no easily accessible tool for the rational design of G4 mutations has been available.

Results

We developed a web-based tool termed G4Killer that is based on the G4Hunter algorithm. This new tool is a platform-independent and user-friendly application to design mutations crippling G4 propensity in a parsimonious way (i.e., keeping the primary sequence as close as possible to the original one). The tool is integrated into our DNA analyzer server and allows for generating mutated DNA sequences having the desired lowered G4Hunter score with minimal mutation steps.

Availability and implementation

The G4Killer web tool can be accessed at: http://bioinformatics.ibp.cz.

Supplementary information

Supplementary data are available at Bioinformatics online.
Facultative sociality in a subterranean rodent, the highland tuco-tuco (Ctenomys opimus)
Authors: O’Brien Shannon L , Tammone Mauro N , Cuello Pablo A , Lacey Eileen A
Published: January 2020

Understanding why social relationships vary among conspecifics is central to studies of animal behaviour. For many species, patterns of space use provide important insights into social behaviour. To characterize the social organization of the highland tuco-tuco (Ctenomys opimus), we used visual observations and radiotelemetry to quantify spatial relationships among adults in a population at Laguna de los Pozuelos, Jujuy Province, Argentina. Specifically, we sought to confirm anecdotal reports that these subterranean rodents are social, meaning that adults share burrow systems and nest sites. Our data indicate that the animals live in spatially distinct groups, although the number of individuals per group varies markedly. Although these relationships were robust with regard to location (above vs. below ground) and type of data (visual vs. telemetry), some groups identified during the daytime fissioned during the night. We suggest that the population of C. opimus at Pozuelos is facultatively social, meaning that individuals display predictable, adaptive differences in social relationships with conspecifics. More generally, our findings add to the growing number of subterranean species of rodents recognized as social, thereby generating new opportunities for comparative studies of these animals aimed at assessing the causes and consequences of variation in social organization.
A Simple, Rapid Method for Paper Chromatography of Barbiturates
Authors: Waddell William J
Published: January 2020

Barbiturates are extracted quantitatively into ethyl ether from biologic fluids buffered to pH 6. A measured portion of the ether extract is then impinged to dryness and the residue spotted on Whatman No. 2 paper that has been previously dipped in alkali and dried. The paper is developed by descending chromatography with chloroform saturated with water. The barbiturate may then be located and a quantitative estimate made by viewing with a mercury lamp; it may also be eluted into an alkaline buffer and ultraviolet spectra determined at several pH's. The extraction from the biologic fluid and development of the chromatogram may be accomplished in about 2 hr.
A Rapid Modification of the Cephalin Cholesterol Flocculation Test
Authors: Rosenberg Arthur A , Eimann Lucille G , O'Leary John
Published: January 2020

A modification of the Hanger (1) cephalin cholesterol flocculation test is described in which the degree of flocculation is determined by instrumental turbidimetric analysis following 4 hr. of cold incubation, centrifugation, and resuspension of sedimented particles. Results of this procedure and the Hanger test are compared.
Determination of Total Iodine in Urine, Stool, Diets, and Tissue
Authors: Benotti Joseph , Benotti Norbert , Pino Samuel , Gardyna Henry
Published: January 2020

A method is presented for determination of total iodine in biologic material. The procedure requires a minimum number of reagents, eliminating the possibility of reagent iodine contamination. The actual cost of equipment for this method is less than for others, and the method offers good replication and excellent recovery of added iodine.
A Micro Method for Serum Cholinesterase
Authors: Garry Phil J , Routh Joseph I
Published: January 2020

A simple colorimetric method for determining serum or plasma cholinesterase has been described. The cholinesterase acts on acetylthiocholine to release thiocholine, which reacts with 5:5-dithiobis-(2-nitrobenzoic acid) to produce a yellow color. The activity is measured after incubation for 3 min. at 37° the reaction is stopped by the excess addition of quinidine sulfate. The difference in absorbance between the blank and test sample is then measured at 412 mµ. Duplicate determinations can be run on 0.1 ml. of serum or plasma, and the method is well suited to laboratories using routine procedures.
Serum Bile Acids in Patients with Liver Disease
Authors: Levin Samuel J , Schwartz Morton K
Published: January 2020

By means of a sensitive fluorometric technic, serum bile acids were determined in patients with various liver diseases. Correlations were shown between the bile acid values and those of transaminase and alkaline phosphatase in cases of liver metastases, and bile acid and transaminase values in cases of viral hepatitis. For most clinical purposes, however, the determination does not yield information which cannot be obtained more readily using currently accepted methods.
Determination of Calcium in Urine by the Chloranilate Method
Authors: Webster William W , Kern William H
Published: January 2020

Evidence is presented that the colorimetric chloranilate calcium method can be accurately applied to urine provided that elimination of interfering substances, which include magnesium, is performed prior to the determination. Isolation of calcium as the oxalate, followed by perchloric acid digestion, has been shown to be an acceptable method whereby urinary calcium can be put in a suitable state for analysis. Allowing the urine to stand for 1 hr. at pH 2 prior to the oxalate precipitation has been shown to be a simple means of eliminating the sampling error due to calcium precipitates.
An Automated p-Nitrophenylphosphate Serum Alkaline Phosphatase Procedure for the AutoAnalyzer
Authors: Morgenstern Stanley , Kessler Gerald , Auerbach Joseph , Flor Richard V , Klein Bernard
Published: January 2020

A new and simplified procedure for the automated determination of serum alkaline phosphatase uses the AutoAnalyzer. The substrate p-nitrophenylphosphate in 2-amino-2-methyl-1-propanol offers the prime advantage of providing directly its own chromogen, p-nitrophenol, following enzyme action. The procedure also permits use of small sample volumes, provides linear reaction rates, and has a simple manifold design. Correlations are presented between the manual procedure and the automated system.
Analysis of Urinary 17-Ketosteroids by Gas-Liquid Chromatography
Authors: Ruchelman Maryon W , Cole V William
Published: January 2020

A method is presented for the resolution of urinary 17-ketosteroids (17-KS) by gas liquid chromatography (GLC) for clinical application. Hot acid hydrolysis with sulfuric acid is followed by ether extraction, 1 N NaOH wash, and NaOH pellets to serve for both purifying and drying agent. All steps take place in the same reaction tube and are adapted for mechanical shaking. The method allows one analyst to prepare 6-8 urine extracts and trimethylsilyl ether (TMS) derivatives in 1 working day, with GLC the next morning. A quantitative fractionation is routine within 24 hr.
The Interference of Chlorpromazine Metabolites in the Analysis of Urinary Methoxy-Catecholamines
Authors: Blumberg Arnold G , Heaton Audre M , Vassiliades John
Published: January 2020

The analysis of urinary methoxy-catecholamines by the method of Pisano (1) could not be applied to the urine of patients who were receiving chlorpromazine. Chlor-promazine and the chlorpromazine metabolites, 7-hydroxychlorpromazine and chlor-promazine sulfoxide, were shown to interfere with the column chromatographic separation and spectrophotometric analysis of the methoxy-catecholamines.
A Continuous Spectrophotometric Method for Measuring the Activity of Serum Alkaline Phosphatase
Authors: Bowers George N , McComb Robert B
Published: January 2020

A continuous spectrophotometric method for measuring serum alkaline phosphatase activity is described. The effects of temperature, pH, substrate concentration, type and molarity of the buffer, sample size, cofactors, and inhibitors on the enzymatic hydrolysis of p-nitrophenyl phosphate were studied. The optimal conditions for assay of serum alkaline phosphatase at 30° were found to be 0.75 M 2-amino-2-methyl-1-propanol buffer, pH30° 10.15, 4 mmole substrate, and 100 µl. or less sample size. Studies of the factors affecting analytical precision-i.e., control of reaction temperature, of reagent manufacture, and of standardization-are discussed. The precision of this method was 2.3% (relative standard deviation) on 10 within day replicates and 5.0% on day-to-day replicates spread over a 5-week period. The range of activity for 258 apparently healthy adult blood donors was 6-110 mU./ml. (International milliunits per milliliter), with a mean of 49 and a standard deviation of 14.
Automated Determination of Serum Glutamic Oxaloacetic Transaminase
Authors: Morgenstern Stanley , Oklander Morris , Auerbach Joseph , Kaufman James , Klein Bernard
Published: January 2020

A simplified and precise automated method is described for the colorimetric determination of serum glutamic oxaloacetic transaminase. The enzymically generated oxaloacetic acid is dialyzed, coupled with Fast Ponceau L, a diazonium salt, to form a colored solution whose absorbance is measured at 455 mµ. Dialysis eliminates the need for a serum control determination, thereby halving the analysis time, which is usually 1 hr. per 40 specimens. Comparison of values obtained using this procedure with and without dialysis shows excellent agreement. Comparison with the spectrophotometric procedure shows good correlation. The results of sample interaction experiments are also presented.
Use of the Activated Partial Thromboplastin Time in the Control of Heparin Administration
Authors: Lenahan Jane G , Frye Sheldon , Phillips George E
Published: January 2020

The activated partial thromboplastin time (APTT) was compared to the whole blood clotting time (WBCT) as a control of heparin administration. The APTT was shown to be a sensitive system for the control of heparin therapy, with the added advantage that the blood can be drawn and taken to the laboratory for assay. The effective therapeutic range in man remains to be established.
A Rapid Electrophoretic Method for the Determination of the Isoenzymes of Serum Lactate Dehydrogenase
Authors: Opher Albert W , Collier Charles S , Miller Joseph M
Published: January 2020

A convenient electrophoretic procedure for the separation and quantitation of lactate dehydrogenase (LDH) isoenzymes is described. The system uses polyacetate Sepraphore III strips.* The areas of activity are shown by incubation with an LDH substrate combined with tetra-nitro-blue-tetrazolium. The reduction of the latter to the purple formazan is quantitatively related to the enzyme activity. Quantitative determination of the individual colored areas is performed by densitometry.
A System of Reading AutoAnalyzer Charts
Authors: Allen Eleanor
Published: January 2020

A convenient method of reading test result during an AutoAnalyzer run is described.
Suction Spectrophotometer Cell
Authors: Seibert R A , Busch H
Published: January 2020

A spectrophotometer cuvet is described which is emptied by suction without re-moval from the instrument. The use of this cuvet saves time and minimizes the chance of breakage. Data from C14 measurements and absorbances of a dye solution show minimal retention error from successive specimens.
Thin-Layer Starch-Gel Electrophoresis
Authors: Lewis Lena A
Published: January 2020

A modification of the starch-gel electrophoresis technic of Smithies is presented,which enables quantitation of the resolved fractions to be carried out with little equipment other than that used for paper electrophoretic fractionation of proteins.A sheet of plastic (Stabilene film) wrapped around a kymograph type drum is evenly coated with starch-gel. The sheet is suspended in an "open strip" Durrum type cell and electrophoresis carried out. After staining with suitable stain to demonstrate proteins, lipids, or other components, the patterns are scanned in a photoelectric densitometer. Results obtained with this procedure show good reproducibility when fractionating solutions of hemoglobin and serum proteins.
Modifications of the Automated Procedure for Blood Phenylalanine
Authors: Hill John B , Summer George K , Hill Hoyle D
Published: January 2020

The automated procedure for blood phenylalanine was modified by the use of glycyl-l-Jeucine and a Corning glass filter No. 7-51. In addition, data were obtained showing that dried blood spots were stable for 11 weeks and samples analyzed at rates of 30 and 60 per hour gave the same results.
X-Ray Spectroscopy in Biology and Medicine
Authors: Mathies James C , Lund Paul K
Published: January 2020

An X-ray emission spectrographic procedure for the quantitative analysis of calcium, sulfur, and phosphorus in urinary calculi has been devised. Duplicate quantitative analyses are possible if 150 µg. of specimen is available. The calcium-, phosphorus-, and sulfur-containing compounds in the sample are quantitatively dissolved in 0.05 M disodium ethylenediaminetetraäcetate prepared in N ammonium hydroxide. An aliquot of this solution, representing 50 µg. of sample, is dried as a thin film on an aluminum foil planchet and quantitated for the indicated elements using the X-ray spectrograph. Preparation of uniform dry films is ensured by adding methylcellulose to the solution of calculus salts. The precision of the method permits estimation of the calcium, sulfur, and phosphorus in each specimen to the nearest whole per cent. Analytic data on 245 specimens of urinary calculi from humans are summarized.
A Rapid Semimicro Method for Determining Protein-Bound Iodine
Authors: Yee Hugh Y , Katz Edwin S , Jenest Edward S
Published: January 2020

An improved 4 hr. semimicro method for the determination of PBI that has an S.D. of 0.30 is presented. The advantageous features include the use of a 0.1-ml. sample size, the removal of inorganic iodide by an anion resin obviating the protein-precipitation step, and the utilization of an ashing time of 35 min. The suitability of this method for the small laboratory becomes apparent in terms of the time saved as well as in the expense of equipment and reagents.
Automated Determination of Serum Glutamic Oxaloacetic Transaminase
Authors: Morgenstern Stanley , Kaufman James H , Klein Bernard
Published: January 2020

A new and sensitive procedure is described for the automated determination of serum glutamic oxaloacetic transaminase using the Robot Chemist. Enzymically generated oxaloacetic acid is directly coupled with the diazonium salt, fast ponceau L, to form a colored solution whose absorbance is measured at 455 mµ. Correlations are presented between this method and the AutoAnalyzer procedure using the same reagent.
Determination of Serum Calcium by Automated Atomic Absorption Spectroscopy
Authors: Klein Bernard , Kaufman James H , Morgenstern Stanley
Published: January 2020

A procedure is presented for the automated determination of serum calcium by atomic absorption spectrophotometry. The serum sample, diluted with acidified lanthanum dichloride, is dialyzed against 0.1 N hydrochloric acid and a portion of the recipient solution is pumped into the atomizer-burner of the spectrophotometer. Data are presented on the precision and reproducibility of the flow system. Addition of calcium to serum shows a mean recovery of 99%. A comparison of the results of analyses on random specimens by permanganate titration and the automated procedure shows good agreement.
Stability of Plasma Enzymes During Storage
Authors: Juul Per
Published: January 2020

For measurement of plasma enzyme stability, 18 specimens of whole blood, plasma, and serum from normal subjects were stored at different temperatures. Eight enzymes were assayed after different times of storage: acetylcholinesterase, pseudocholinesterase, glutamic-oxaloacetic transaminase, glutamic-pyruvic transaminase, lactic dehydrogenase, acid and alkaline phosphatases, and amylase. At -200° all enzymes except lactic dehydrogenase were stable for 8 days, while at 38° all except amylase were unstable. At 4° the stability of the enzymes differed in whole blood, plasma, and serum, with a tendency toward greater stability than is usually reported.
Simplified Microestimation of Fibrinogen and Seromucoid in Plasma
Authors: Pryce J D
Published: January 2020

Simplified methods for the microestimation of fibrinogen and seromucoid in plasma are described, and their relationship is discussed. The normal range corrected for age and sex is given.
Calcium Determinations in Kinetic Studies
Authors: Harrison Joan , Hitchman A J W , Finlay J M
Published: January 2020

Published reports of a fraction of blood calcium that does not equilibrate with a tracer has created a controversy that challenges the validity of much calcium kinetic data. To resolve this controversy, calcium specific-activity measurements were made on blood and urine samples in vitro and in vivo. The experiments were designed to provide maximal sensitivity for demonstrating non exchangeable calcium. A new and accurate method for urine calcium determinations was used. The results demonstrated complete equilibration between tracer and stable blood calcium. We suggest that published evidence of non exchangeable calcium in blood and urine is erroneous due to inaccurate urine calcium determinations.
Application of Thin-layer Chromatography to the Quantitation of Plasma Neutral Lipids and Free Fatty Acids
Authors: Louis-Ferdinand Robert T , Therriault Donald G , Blatt William F , Mager Milton , Metheson Edward J
Published: January 2020

Neutral lipids and free fatty acids were extracted from plasma and separated on thin-layer chromatoplates coated with silica gel G. The plates were charred by heating after spraying with dichromate-sulfuric acid, and then evaluated densitometrically. Plasma analyses obtained by this procedure were compared with parallel determinations performed by established chemical technics.
Simultaneous Determination of Pregnanediol and Pregnanolone in Urinary Extracts by Gas Chromatography
Authors: Guarnieri M , Barry R D
Published: January 2020

A method for the simultaneous determination of pregnanediol and pregnanolone in urinary extracts by gas chromatography is described. The method involves prior enzymatic hydrolysis of the steroid conjugates, chloroform extraction, and quantitation by means of gas chromatography.
The Stability of a Reconstituted Serum for the Assay of Fifteen Chemical Constituents
Authors: Hanok Albert , Kuo Jeremiah
Published: January 2020

A study was made of serums stored at refrigerator (10°) and freezer (-15°) temperatures in relation to the subsequent effect on the following assays: sodium, potassium, chloride, carbon dioxide, protein, albumin, calcium, alkaline phosphatase, glutamic oxalacetic transaminase, bilirubin, urea nitrogen, glucose, uric acid, creatinine, and phosphorus. Data showing the period for which a reconstituted serum may be stored under these conditions are presented.
A Study of 2,4,6-Trinitrobenzenesulfonic Acid for Automated Amino Acid Chromatography
Authors: Brown Harold H
Published: January 2020

The reaction of 2,4,6-trinitrobenzenesulfonic acid (TNBS) with amino acids was investigated by a static system to develop optimum conditions for application to automated amino acid chromatography. TNBS was found to be a very simple and sensitive reagent, easier to use than ninhydrin. The reaction occurs quite rapidly at room temperature, eliminating the requirement of a heating bath. The major disadvantage is a much lower sensitivity to the imino acid proline than to the amino acids.
Determination of Body Water Content Using Trace Levels of Deuterium Oxide and Infrared Spectrophotometry
Authors: Stansell Marion J , Mojica Luis
Published: January 2020

A procedure is described for the determination of total body water content of human subjects using 11- to 12-gm. doses of deuterium oxide (D2O), vacuum sublimation of serum samples, and quantitation of the deuterium by infrared spectrophotometry at 2510 cm.-1. The coefficient of variation based on day-to-day procedure reproducibility is less than 2%. D2O added to serum is completely recovered in the sublimation and assay operations. The D2O dilution procedure compares favorably with the tritium dilution technic, with values obtained on 45 out of 46 individuals falling within the ±3 combined S.D. limits for the two methods. The significance of the total body water data is discussed.
The Effect of Formalin and the Duration of Acid Hydrolysis on Free and Conjugated Urinary 17-Ketosteroids
Authors: Goldzieher Joseph W , de la Pena Armando
Published: January 2020

The recovery of five free ketosteroids, three glucuronides, and six sulfates, added to water or urine and subjected to acid hydrolysis for various lengths of time, was investigated. Dehydroepiandrosterone (DHEA) in all its forms was most susceptible to destruction. The behavior of glucuronides and sulfates differed, and no single set of conditions provided equal recovery for all conjugates. A compromise time of 30 min. of hydrolysis appeared to be optimal. The addition of formalin diminished nonspecific chromogens in a variable manner, but also accelerated destruction of DHEA and decreased the recovery of ketosteroid sulfates.
Creatine Phosphokinase Activity in Myocardial Infarction, Heart Failure, and Following Various Diagnostic and Therapeutic Procedures
Authors: Crowley Leonard V
Published: January 2020

The creatine phosphokinase(CPK) test based on the method of Okinaka et al. (1) was compared with the glutamic oxalacetic transaminase (GOT) test of Reitman and Frankel (2) in patients with myocardial infarction, cardiac failure, and following various diagnostic and therapeutic procedures. The CPK method used was somewhat less discriminatory than the GOT method in detecting myocardial infarction. The CPK test possessed greater specificity, since it was not elevated in congestive cardiac failure, while the GOT test was elevated in 25% of the patients with heart failure. Therefore, the CPK test offered a real advantage when evaluating suspected infarction in the presence of cardiac failure. CPK activity may be elevated when the GOT test is normal, indicating the advantage of performing more than one enzyme procedure in suspected myocardial infarction.

Both GOT and CPK were elevated in many patients following surgical operation and cardiac catheterization. No CPK elevations were encountered after electroconvulsive therapy, and CPK was only occasionally elevated following coronary arteriography.
Rapid Detection of Organic Phosphorus Poisons
Authors: Fischl J , Pinto N , Gordon C
Published: January 2020

Strips of filter paper are impregnated with a buffered acetylcholine substrate solution, containing phenol red as an indicator, and 1,2-propyleneglycol serving as an inhibitor of bacterial decomposition and as a wetting agent. The test is suitable for the detection of the poison in vivo, as well as in suspected materials such as food, clothing, water, soil, and air samples. The test is based on the inhibition of acetylcholinesterase by the organophosphoric group of the substances. In positive tests the indicator paper turns pink-to-violet and in negative tests it turns a yellow color.
A New Time-Saving Method for Determining Nitrogen in Biologic Material
Authors: Dambacher M , Gubler Alice , Haas H G
Published: January 2020

A new method for the determination of nitrogen in biologic material is described. It is based on an improved ashing procedure and the Berthelot reaction in which nitrogen is converted to indophenol. The concentration of this substance is determined photometrically. The proposed method yields the same results as the Kjeldahl procedure; however, it offers a higher degree of sensitivity combined with the same degree of accuracy. In addition, the determination requires only 4 hr., in comparison to 24 hr. for the Kjeldahl method.
Comparison Between Thiocholinesters and o-Nitrophenylbutyrate as Substrates in the Assay of Serum Cholinesterase
Authors: Szasz Gabor
Published: January 2020

The technical and clinical usefulness of three substrates for serum cholinesterase were compared. The diagnostic value of acetylthiocholine was equal to that of butyrylthiocholine and superior to that of o-nitrophenylbutyrate. Technically, butyrylthiocholine is superior to the other two substrates chiefly because of its greater affinity for serum cholinesterase. A kinetic method using o-nitrophenylbutyrate is described that is capable of carrying out 60 tests per hour with good results.
Semimicro Method for Determination of Serum Uric Acid Using EDTA—Hydrazine
Authors: Patel C P
Published: January 2020

A semimicro method is described for the determination of uric acid by manual and automated procedures. Serum uric acid reduces phosphotungstic acid in an alkaline medium of EDTA sodium tungstate and hydrazine sulfate, the latter being used as a color intensifier. The use of sodium tungstate eliminates the development of interfering turbidity encountered with other alkalizing reagents. This method requires only 0.2 ml. of serum. The presence of ascorbic acid, sodium salicylate, cysteine, and/or glucose does not interfere. A linear relationship is obtained upon comparing this method with the sodium carbonate and the differential ultraviolet spectrophotometric methods.
An Automated Estimation of Serum Globulins
Authors: Read B A N
Published: January 2020

A procedure is described for the automatic determination of serum globulin concentration, which is estimated by the turbidity produced by precipitation in a sodium sulphate-sodium sulphite solution.
Practical Acetate Membrane Overlay Method for Multiple Sample LDH Isoenzyme Separation and Quantitation
Authors: Beals Daniel F , Stedman Enid , Kouns D Michael
Published: January 2020

A rapid microtechnic utilizing cellulose acetate membranes for the electrophoretic separation of LDH isoenzymes is described. The use of cellulose acetate for both migration and reagent application represents a relatively inexpensive and reproducible method which avoids many of the inherent problems associated with agar gels. The technic can be used for the analysis of a relatively large number of samples. Normal distribution values of the LDH isoenzymes were established.
Direct Nephelometric Determination of Protein in Small Amounts of Cerebrospinal Fluid
Authors: Shin Yung S
Published: January 2020

A spectrophotofluorometer is used as a nephelometer for determining small amounts of protein by turbidity measurements.
A Kinetic Photometric Method for Serum γ-Glutamyl Transpeptidase
Authors: Szasz Gabor
Published: January 2020

A kinetic method is described for the determination of γ-glutamyl transpeptidase activity in serum. Optimal conditions for the reaction were ascertained, normal values in milliunits per milliliter at 25° established, and the reliability of the method examined. γ-Glutamyl-p-nitroanilide in ammediol-HCl buffer at pH 8.2 is employed as substrate. The method requires only 0.1 ml. of serum and, using an automatic cuvet positioner and recorder as well as an automatic diluter, more than 60 determinations can be carried out in 1 hr. On the basis of a large number of determinations, the method was shown to be technically excellent and clinically valuable.
A Rapid Method for Checking the Purity of Radioiodinated Human Luteinizing Hormone
Authors: Abraham Guy E
Published: January 2020

A method using dextran-coated charcoal has been used to check the purity of radioiodinated human luteinizing hormone. The results obtained by this method compared favorably with those obtained by the double antibody technic, which takes much longer to perform. The reliability of the method using dextran-coated charcoal is demonstrated and its practicability discussed.
Prediction of Immunoglobulins from Patterns of Cellulose Acetate Electrophoresis
Authors: Gault M H , Hsieh S , Elzer E
Published: January 2020

The concentrations of serum immunoglobulins (Ig) G, A, and M were correlated with specific features in the β-γ region of densitometer patterns of serum protein electrophoresis on cellulose acetate membranes; visual analysis of densitometer patterns permitted semiquantitative prediction of values for IgG and IgA. Important immunoglobulin abnormalities, particularly elevations of IgA, were seen in some cases even when normal values were obtained from analyses of electrophoresis by usual densitometer integrator technics; many such instances were detectable by inspection of the densitometer tracing.
Aldolase
Authors: Pinto Patrick V C , Van Dreal Paul A , Kaplan Alex
Published: January 2020

The Sigma and Boehringer reagent kits for measuring aldolase activity by a colorimetric method were examined critically. The original Sibley and Lehninger (1) procedure was more satisfactory than the modifications made by the kit manufacturers. Serum aldolase activity measured by the Sigma procedure and our modification of the Sibley-Lehninger method agreed within a standard deviation of ± 2 IU; values obtained with the Boehringer kit were about 50% low.
Enzyme Content of Casts in Chronic Renal Disease
Authors: Wolf Paul L , Horwitz Jerome P , Pierce James , Small Michael , Ing Todd S
Published: January 2020

An investigation of enzyme content of diseased human kidneys was carried out. A broad spectrum of enzymes was studied histochemically in these kidneys. A surprising finding of the presence of various lysosomal, microsomal, and nuclease enzymes was demonstrated in epithelial casts in the kidneys. In contrast, mitochondrial enzymes were not present in the epithelial casts. This study has demonstrated that epithelial casts still retain certain enzymatic activities and are not enzymatically inert.

Recently, we subjected portions of kidneys removed from patients with chronic renal disease (chronic pyelonephritis and chronic glomerulonephritis) prior to transplantation to a comprehensive enzyme histochemical analysis. We observed marked differences in the enzyme content of intratubular epithelial casts.
Rapid Porphyrin Screening of Urine, Stool, and Blood
Authors: Haining Robert G , Hulse Thomas , Labbe Robert F
Published: January 2020

Simplified chemical screening tests and an apparatus to facilitate their performance have been developed for porphyrins. The tests are applicable to urine, stool, and blood. The procedures for different specimens are essentially identical and can be performed in a few minutes with a minimum of reagents and apparatus. Results obtained are usually sufficiently definitive to permit differential diagnoses of porphyrias and porphyrinurias without resort to separation or quantitation of the individual porphyrins.
Gas Chromatographic Analysis for Anticonvulsant Drugs in Biologic Fluids
Authors: Pippenger C E , Gillen H.W.
Published: January 2020

A rapid quantitative method for estimation of Mesantoin, Nirvanol, phenylethyl-malondiamide, phenobarbital, Mysoline, and Dilantin, in plasma, urine, and cerebro-spinal fluid by gas chromatography is described. A Jarrell-Ash flame ionization gas chromatograph with a 6-ft, 4-mm ID glass column packed with 1% HIEFF-8-BP on Gas Chrom Q 100/120 mesh was utilized. The pressure of nitrogen gas (carrier) at the inlet was 18 psi; temperatures: 260° at the injector, 250° in the column, and 295° at the detector.
The Detection of Basic and Other Drugs in Urine by Distillation and UV Spectrophotometry
Authors: Tompsett S L
Published: January 2020

An investigation has been described of the use of a distillation procedure, which is followed by UV spectrophotometry, for the detection and determination of a large number of volatile basic drugs in urine, The use of additional UV spectrophotometry and gas-liquid chromatography is described as follow-up procedures.
Estimation of Calcium, Magnesium, and Phosphorus in Diet and Stool
Authors: Husdan H , Rapoport A
Published: January 2020

A procedure that is simple and convenient for general use for the estimation of calcium, magnesium, and phosphorus in diet and stool is described. It includes a HNO3—HClO4 digestion in a micro-Kjeldahl flask. Calcium subsequently may be estimated by atomic absorption spectrophotometry or by the Clark-Collip procedure, magnesium by atomic absorption spectrophotometry, and phosphorus by the method of Fiske and SubbaRow. Chromium, used as a focal collection marker, does not interfere in the measurement of calcium and magnesium, whereas the measurement of phosphorus requires a preliminary ketone extraction of the chromium. The precision and accuracy of the procedure have been evaluated and found to be quite satisfactory.
A Simplified Procedure for the Assay of 5'-Nucleotidase
Authors: Rieder Sidney V , Otero Mirta
Published: January 2020

5'-Nucleotidase* activity is measured by inhibiting phosphatase activity with 0.01 M Ni+2 and eliminating the requirement for protein removal before measurement of phosphate. The normal range for adults is given as 1.6-14.0 units/liter of serum, with no apparent difference between the sexes.
Serum Glutamic Oxalacetic Transaminase Assay Using the Sequential Multiple Analyzer (SMA 12/30)
Authors: Moore John J , Sax Sylvan M
Published: January 2020

The SMA-12/30 method for serum glutamic oxalacetic transaminase assay gives higher values than are obtained with a reference spectrophotometric method for some serums. A modification of the manifold is made to permit the running of serum blanks. Blank corrections on 466 serum samples indicate that dialysis does not eliminate the need for the blank determination. Acetoacetate interferes in the SMA-12/30 method. The possibility of other interfering substances has not been ruled out.
Between-Bottle Variation as Source of Error in Quality Control Sera
Authors: Padmore G R A , Gatt J A
Published: January 2020

Between-bottle variation in relation to analytical error in the determination of constituents of the same batch of quality control serum has been examined statistically for sera from two manufacturers. Calcium and chloride were measured. Variation between bottles—as a result of errors in dispensing the original serum, lack of homogeneity, or reconstitution error—is less than the analytical error of the methods used here.
New Amylase Substrate and Assay Procedure
Authors: Babson Arthur L , Tenney Susan A , Megraw Robert E
Published: January 2020

This report describes a new procedure for serum amylase assay. A novel substrate, dyed amylopectin, is used that combines the advantages of saccharogenic and amyloclastic methods. Serum amylase hydrolyzes the dyed amylopectin into ethanol-soluble fragments, which are quantified colorimetrically after serum proteins and unhydrolyzed substrate are precipitated with alcoholic tannic acid. The substrate is prepared by coupling Reactone Red 2B to amylopectin in alkaline solution. Unreacted dye is removed by gel filtration. The clear red solution of dyed amylopectin is buffered and diluted to a standard concentration; it can be preserved indefinitely by lyophilization. The assay procedure is the following: 0.2 ml serum is added to 1 ml substrate at 37°C. After incubation for 10 min, 5 ml of alcoholic tannic acid are added, and the mixture is centrifuged. Absorbance of the supernatant solution at 540 nm is a linear function of amylase activity. Serum blanks are not required. The results correlate well with the saccharogenic assay of Somogyi.
Thin-Layer Chromatography of Urinary Imidazoles
Authors: Humbel R
Published: January 2020

A simple technique is described for the identification of urinary imidazoles by thin-layer chromatography on cellulose. It is especially suitable for the diagnosis of histidinemia, and it can give information about other anomalies in histidine metabolism.
Rapid Method for Homogenizing Tissue Samples for Liquid Scintillation Counting
Authors: Adams Lonnie D , Curry Larry L , Bartek Methodius J
Published: January 2020

Quick-freezing in liquid nitrogen allows a great variety of animal organs, including those rich in connective tissue, to be rapidly and completely pulverized, thus rendering them more readily soluble in the mixture used for scintillation counting. We have constructed a pulverizing assembly from items normally found in the research laboratory that conveniently facilitates this operation.
Automated Method for Determination of Serum Calcium by Use of Alizarin
Authors: Frings Christopher S , Cohen Patricia S , Foster Lowell B
Published: January 2020

An automated method is described for determining serum calcium by measuring the red chromogenic complex formed by calcium and alizarin. About 40 µl of undialyzed serum is added directly to one reagent to pro-duce the color, which follows Beer's law at 599 nm to a concentration of 15.0 mg of calcium per 100 ml, with a coefficient of variation of 2.5%. Serum calcium concentrations, as measured by our method, compare favorably with those by the corresponding manual method and by atomic absorption spectrophotometry
Measurement of Human Serum Ceruloplasmin by Its p-Phenylenediamine Oxidase Activity
Authors: Sunderman F William , Nomoto Shozo
Published: January 2020

Optimum reaction conditions were evaluated for assay of serum ceruloplasmin by measurement of its p-phenylenediamine oxidase activity. The pH optima of p-phenylenediamine oxidase activities of human and rat ceruloplasmins were 5.45 and 5.2, respectively. The p-phenylenediamine oxidase activity of rat ceruloplasmin was markedly inhibited by phosphate (0.1 mol/liter), that of human ceruloplasmin only slightly. These reaction conditions were judged to be optimum for the ceruloplasmin assay: (a) substrate: p-phenylenediamine dihydrochloride, 8.9 mmol/liter; (b) buffer: acetate, 0.1 mol/liter; (c) chloride concentration: 21 mmol/liter; (d) serum dilution: 31-fold; (e) incubation: 37°C for 30 min; (f) spectrophotometry: 530 nm (vs. a "serum blank" containing NaN3). Using these reaction conditions, we devised an improved technique for measuring serum ceruloplasmin. The coefficients of variation of replicate analyses by this technique were 1.25% (for "within-run" precision) and 2.8% (for "day-to-day" precision). The mean concentration of ceruloplasmin in sera from 29 healthy men was 0.315 g/liter (SD = ± 0.049, range = 0.233 to 0.402).
Apparatus for Collecting Fractions from Density Differential Interfaces and Its Use in Gravimetric Measurement of Total Myelin
Authors: Hill Robert M , Bruzek Virginia E
Published: January 2020

An apparatus is described for the precise preparation of density differential interfaces and for quantitative collection of samples from these interfaces. A method is described in which the apparatus is used to quantitatively extract and measure myelin from nerve tissue. Myelin is separated from a homogenate of nerve tissue by density differential ultracentrifugation. The washed myelin is dried. The rate of drying undergoes a sharp change when the loss of free water gives place to the loss of structural water. These two rates are used to calculate the quantity of normally hydrated myelin present.
Isolation and Quantification of Serum Uric Acid by Adsorption Chromatography
Authors: Simkin Peter A
Published: January 2020

Established methods for determining the serum uric acid concentration are colorimetric, enzymatic, or combination of the two. An alternative method, based on the affinity of purines for polyacrylamide resin, has been developed. Uric acid, more strongly adsorbed than other major serum constituents, elutes later (with phosphate buffer, pH 7) from a polyacrylamide column. The separated serum uric acid is measured by continuously monitoring the ultraviolet absorptivity of the column effluent. Uric acid is separated satisfactorily from its metabolites, a feature useful in studies of the metabolism of radiolabeled uric acid.
An Automated Micromethod for Determination of Serum Glucose, with an Improved o-Toluidine Reagent
Authors: Moorehead Wells R , Sasse Edward A
Published: January 2020

An automated method has been developed in which a new o-toluidine reagent is used for the microanalysis of glucose. The reagent is 1.3 times as sensitive as the o-toluidine reagent commonly used in manual procedures. The reagent does not significantly alter the life expectancy of manifold tubing made of polyvinyl chloride. The automation includes a dialysis step and possesses the desirable features of the manual methods, including the greater specificity as compared with methods based on reducing properties. Results of this automated method obey Beer’s law, are very reproducible (the coefficient of variation is approximately 1.5%), and are not significantly different from those obtained manually. The method requires 75 µl of sample.
A Method for Determining Nitrofurantoin in Urine in the Presence of Phenazopyridine Hydrochloride and Its Metabolites
Authors: Hollifield R D , Conklin John D
Published: January 2020

The high urinary drug concentrations usually encountered after administering nitrofurantoin in the chemotherapy of urinary tract infections are often measured by the nitromethane—Hyamine method. We show here that, if the urinary tract analgesic, phenazopyridine hydrochloride, and its related metabolite(s) are in the urine, they interfere with this determination of nitrofurantoin. Nevertheless, the nitromethane—Hyamine method may be modified to determine nitrofurantoin quantitatively in urine collected from human subjects who have been treated with the analgesic and nitrofurantoin concomitantly.
Nomograms for Calculation of Urea Clearance
Authors: Gindler E Melvin
Published: January 2020

Two nomograms are given for use in calculating standard, C[unknown], or maximum, Cm, urea clearance. The first nomogram calculates the urine flow rate, f, from the urine collection time and volume data. With the second nomogram, values of f and urea nitrogen concentrations in blood serum (or plasma) and urine are used to calculate either C[unknown] or Cm, according to the value of f. There is no intermediate calculation of √f. Examples of the use of the two nomograms in the calculation of C[unknown] or Cm are given.
Evaluation of a New Procedure for Measuring Serum Creatine Kinase Activity
Authors: Henry Wilkinson J , Steciw B
Published: January 2020

A new spectrophotometric microtechnique for the determination of serum creatine kinase activity, in which all reagents are provided in a single com-pressed tablet, has been evaluated. The procedure depends upon coupling the creatine phosphate-ADP reaction with the hexokinase and glucose-6-phosphate dehydrogenase reactions. The new technique is quick, relatively simple, and gives results which compare favorably with the conventional spectrophotometric method in precision and sensitivity. It requires a sample volume of 10 Al, and values ranging from 10 to1600 U/liter can be determined without dilution. Gross hemolysis leads to erroneously high values, but the error is negligible with slightly hemolyzed specimens. A provisional normal range has been established
Determination of Fecal Triglycerides and Fatty Acids of Medium Chain Length by Electrical Capacitance and by Petroleum Ether Extraction
Authors: Hallaway Ben E , Sandberg Rodney
Published: January 2020

The extraction method of Friedner and Moberg for determining fecal lipids gave recoveries of medium-chain triglycerides and of octanoic and decanoic acids from stool specimens averaging 103, 97, and 107%, respectively. Fatty acids did not esterify appreciably during extraction. Accordingly, this method is suitable for use in measuring intestinal absorption of triglycerides of medium chain length. The electrical capacitance method of Wolochow et al. is unsuited to the determination of total lipids in a mixture of triglycerides and fatty acids of long and medium chain length because these substances differ widely in capacitance.
A Simple Screening Method for Detecting Isovalerylglycine in Urine of Patients with Isovaleric Acidemia
Authors: Ando Toshiyuki , Nyhan William L
Published: January 2020

Isovaleric acidemia is one of an enlarging group of inherited metabolic diseases now recognized to cause death in the neonatal period. Rapid, simple detection is essential for diagnosis of these conditions. We describe a method that fulfills these criteria for isovaleric acidemia. Excretion of isovalerylglycine in the urine more reliably indicates the condition than the presence of volatile isovaleric acid in the blood. Isovalerylglycine is extracted from urine and separated by thin-layer chromatography from other constituents of urine. It is detected by spraying the chromatogram with bromcresol purple. Isovalerylglycine does not appear in normal urine.
Preparation of 14C-Labeled Series I and III Porphyrins
Authors: Koskelo Pentti , Toivonen Ilkka
Published: January 2020

A method is described for preparing series I and III porphyrins, 14C-labeled, in sufficient amounts for use in clinical and biochemical experiments.
Two-Dimensional Thin-Layer Chromatography on Two-Layer Plates of Amino Acids
Authors: Kraffczyk F , Helger R , Lang H
Published: January 2020

Separation of the amino acids in urine by use of thin-layer chromatography (TLC) has hitherto required that the specimen be first desalted and then chromatographed in two dimensions with at least two pairs of developing solvent systems. We wished to simplify both steps. The customary method of desalting on a column is replaced by desalting on a plate that supports a strongly acid cation-exchanger and a cellulose layer. This method, originally developed for one-dimensional TLC, is used here for two-dimensional TLC. Urine is applied to the ion-exchange layer and strong acids and neutral substances are removed with water. The amino acids are then chromatographed into the cellulose layer, and are separated there two dimensionally with a newly devised pair of developing solutions. This pair of solvents separates nearly all of the amino acids in urine.
Ultraviolet-Absorbing Compounds in Urine of Normal Newborns and Young Children
Authors: Vavich Joel M , Howell R Rodney
Published: January 2020

Ultraviolet-absorbing compounds excreted in the urine of normal newborns, infants, and children have been measured by high-pressure anion-exchange chromatography. The chromatograms increased in complexity with increasing age of the subject. Preliminary data indicate that the excretion of pseudouridine and uridine was significantly higher in newborns and infants than in older children and adults. Excretion of hippuric acid was low in the newborn. Excretion of ergothioneine was lower in older children than in newborns, infants, or adults. However, hypoxanthine excretion was constant in all groups.
Semiautomated Method for Measurement of Dopa in Plasma
Authors: Spiegel Herbert E , Tonchen Alice E
Published: January 2020

A semiautomated fluorometric method for analysis of dopa [3-(3,4-dihydroxyphenyl)-L-alanine] is described, with ferricyanide used as an oxidant. To separate dopa from interfering catecholamines it is adsorbed on alumina, eluted with 0.1N HCl, then adsorbed on and eluted from a cation-exchange column. The method is suitable for use with a large volume of samples. It provides a simple, sensitive, accurate, and reproducible analytical technique for routine use.
Emergency Screening of Urine, Plasma, or Gastric Contents for Barbiturates
Authors: Helman Edith Zak
Published: January 2020

A procedure is described for emergency screening for barbiturates that requires no specialized equipment and can be performed in less than 10 min; thus lending itself to emergency-room use. The method is highly specific and can be used to detect as little as 1 mg/100 ml.