bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of Visualization Methods Used to Measure the Lecithin/Sphingomyelin Ratio in Amniotic Fluid
Authors: Olson E B , Graven S N 
Published: January 2020

Abstract
Amniotic fluid lecithin/sphingomyelin ratios are commonly determined after these phospholipids are separated by thin-layer chromatography and made visible by one of several methods. Here, we comprehensively survey the experiences of other authors with these visualization methods, and we have evaluated the available techniques. We report standard curves of dipalmityl lecithin and sphingomyelin made visible by six of these methods. Bromthymol blue in ammonia vapor or charring with either sulfuric acid:water (1:1 by vol) or potassium dichromate (10 g/liter) in sulfuric acid:water (7:3 by vol) produces spots of similar intensity for both phospholipids. However, iodine vapor, a phosphomolybdic acid dip, or charring with ammonium sulfate, produces more intense sphingomyelin spots. We recommend that (a) visualization methods be used that produce similar spot intensities for both phospholipids so that the ratio determined reflects the actual relative amounts of lecithin and sphingomyelin, and (b) if clinical predictions are made based on interpretation tables provided in the literature, the visualization method on which the ratio interpretation tables are based gives results that correlate with the actual ratio.
Fully Automated, All-Enzymatic Triglyceride Method Adapted to the GEMSAEC Centrifugal Analyzer, with Use of an Aqueous Triolein Standard
Authors: Chong-Kit R , McLaughlin P 
Published: January 2020

Abstract
We describe a completely automated enzymatic method for estimating serum triglycerides with a centrifugal analyzer (ENI-GEMSAEC). Accuracy and precision (CV, 2 to 4.8%) and the upper limit of linearity (400 mg/100 ml) are monitored by use of newly developed, clear, aqueous triolein standards. A modified computer program (FOCAL 8) is used for data manipulation and correcting absorbance to zero reaction time. Results cornpare well with those obtained by an automated fluorometric procedure and a manual enzymatic procedure.
Factors Contributing to Intra-Individual Variation of Serum Constituents: 4. Effects of Posture and Tourniquet Application on Variation of Serum Constituents in Healthy Subjects
Authors: Statland Bernard E , Bokelund Henning , Winkel Per 
Published: January 2020

Abstract
We studied the effects on 18 serum constituents of posture and prolonged tourniquet application. The subjects were 11 healthy men, ages 20-25 years. The assays were performed on the AutoChemist Multi-Channel Analyzer (AutoChem Instrument AB, Lidingö, Sweden). To compensate for the within-hour variation in these constituents, we drew blood samples at 1100 h and 1130 h on several days. The 1100-h sample was taken after the subjects had been sitting erect for 60 min. The 1130-h sample followed different posture regimens: Control day: sitting for 15 min; experimental days: after (a) being supine for 30 min, (b) standing for 30 min, and (c) sitting erect for 30 min. The 1130-h/ 1100-h ratios for the three experimental days were compared with those for the control day. Significant differences (P &lt;.05) were found for serum potassium, calcium, total protein, albumin, aspartate aminotransferase, and acid phosphatase under condition a; for phosphate ion, total protein, total lipid, cholesterol, and alkaline phosphatase under condition b; and for aspartate aminotransferase under condition c. The effect of a 3-minute tourniquet application was similarly studied. The ratio of the "prolonged tourniquet application day" differed significantly from the control day with regard to serum potassium, total protein, iron, total lipid, cholesterol, aspartate aminotransferase, and bilirubin. Significance of posture and tourniquet time in blood-sampling and their effect on total intra-individual variation are discussed.
Gas—Liquid Chromatography of Phenylalanine Metabolites in Urine and Sera of Hyperphenylalaninemic and Phenylketonuric Patients
Authors: Kitagawa Teruo 
Published: January 2020

Abstract
Gas—liquid chromatographic methods are described for measuring phenylalanine metabolites in urine and serum. These were studied in controls and in various types of hyperphenylalaninemics. The plasma phenyllactic acid concentration increased as the serum phenylalanine concentration increased. The 24-h urinary excretion of both phenylalanine and phenyllactic acid depends upon their respective concentrations in serum.
Optimizing Nephelometric Measurement of Specific Serum Proteins: Evaluation of Three Diluents
Authors: Killingsworth Lawrence M , Buffone Gregory J , Sonawane Meena B , Lunsford Glennie C 
Published: January 2020

Abstract
Three diluents were studied, to determine which is the best for the automated immunochemical measurement of specific serum proteins. Nine serum proteins (orosomucoid, α1-antitrypsin, α2-macroglobulin, haptoglobin, transferrin, C3, IgG, IgA, and IgM) were measured in physiological saline (9 g NaCI/liter), tris(hydroxymethyl)aminomethane buffer (0.01 mol/liter; pH 7.4), and physiological saline containing polyethylene glycol ("PEG 6000," 40 g/liter). Criteria were: reaction rate, analysis rate, carryover between samples, steady-state approximation, precision, and correlation with other methods. Saline containing polyethylene giycol is the best of the three diluents for use in continuous-flow nephelometric analysis of serum proteins.
Measurement of Ceruloplasmin from Its Oxidase Activity in Serum by Use of o-Dianisidine Dihydrochloride
Authors: Schosinsky Karl H , Lehmann H Peter , Beeler Myrton F 
Published: January 2020

Abstract
We have developed a new method for determination of serum ceruloplasmin from its oxidase activity, in which o-dianisidine dihydrochloride is used as substrate. o-Dianisidine dihydrochloride is more stable than is the more widely used p-phenylenediamine substrate, and forms a stable product that is measured at 540 nm. Correlation was good between results of this method and those obtained with both a p-phenylenediamine substrate method (r = 0.98) and a radial immunodiffusion procedure (r = 0.97). There is little or no interference from reducing or colored components of serum. The coefficient of variation (day-to-day) for the method was 4.2%. A normal range of 62-140 U/ liter has been determined by the reported method.
Simple Enzymatic Determination of Polysaccharide (Glycogen) Content of Animal Tissues
Authors: Murat J C , Serfaty A 
Published: January 2020

Abstract
For determination of (chiefly) glycogen content, tissue homogenates in citrate buffer are mixed with exo-1,4-α-glucosidase (EC 3.2.1.3). Liberated glucose is estimated with a Beckman Glucose Analyzer. This method was checked with commercial glycogen (from oysters) and with fish (carp) tissues. Comparative measurements were made with the classic Good-Kramer-Somogyi method [J. Biol. Chem. 100, 485 (1933)]. The described method, suitable for small samples of tissue, such as those obtained by biopsy, seems to be simple and accurate, but gives values 5 to 10% higher than those given by the classic KOH-ethanol method.
Frequency of Clinical Toxicology Test-Ordering (Primarily Overdose Cases) and Results in a Large Urban General Hospital
Authors: Lundberg George D , Walberg Clifford B , Pantlik Violet A 
Published: January 2020

Abstract
We report one year's analytical data from a clinical toxicology laboratory of a large urban hospital. The laboratory was designed to perform tests on seriously ill patients believed to be suffering from possible drug overdose. The data describe the types and numbers of tests requested and percent positive. Barbiturates, ethanol, a "hypnotic screen," phenothiazines, and salicylates were the leading requests and positive findings among the 63 drug determinations studied. The mechanism of organizing a laboratory along "patient-focused" lines is described and the clinician—laboratory interface is discussed. We believe that these data could be of value to anyone contemplating offering a clinical toxicology service for the first time or in assisting in the reorganization of their present service.
Rapid Gas Chromatographic Method for Quantitation of Ethchlorvynol ("Placidyl") in Serum
Authors: Evenson M A , Poquette M A 
Published: January 2020

Abstract
A rapid, simple, and sensitive method for quantitation of ethchlorvynol by gas chromatography has been developed. Instrument response is linear to a concentration of 200 mg/liter (2.0-ml sample of serum). Day-to-day (20 days) precision of a 15 mg/liter serum pool was 0.85 mg/liter (SD) and 5.6% (CV). For 30 samples analyzed by both the gas chromatographic method and a colorimetric method, the correlation plot had a slope of 0.989, x and y intercepts near zero, and a correlation coefficient of 0.997. Mean recovery of ethchlorvynol added to serum was 87%. Subsequently, all standards were prepared in serum, to compensate for the nonquantitative yield and to help assure accuracy. Sera from healthy controls and from hospitalized patients contain no endogenous interfering substances, nor did any of a series of commonly prescribed drugs interfere.
Use of Fluorescamine ("Fluram") to Detect Amphetamine in Urine by Thin-Layer Chromatography
Authors: Klein Bernard , Sheehan Joan E , Grunberg E 
Published: January 2020

Abstract
A "Fluram" (fluorescamine; 4-phenylspiro[furan-2(3H)-1'-phthalan]-3,3'-dione) spray reagent will detect as little as 250 ng of amphetamine in an extract of amphetamine-containing urine, after it has been separated by thin-layer chromatography. The fluorescence is stable for about 20 h and can be renewed by respraying. Fluram spray does not interfere with reagent sprays used to detect other drugs of abuse. Amphetamine on the thin-layer plate can be measured by extracting the fluorescent area of silica gel and measuring the fluorescence in a fluorimeter. Recovery of 1.0 µg and 2.0 µg of amphetamine averaged 69% and 67%, respectively.
Fluorometric Determination of Propoxyphene
Authors: Valentour James C , Monforte Joseph R , Sunshine Irving 
Published: January 2020

Abstract
We report a sensitive fluorometric method of analysis of propoxyphene in biological materials. 4-Chloro-7-nitrobenzo-2,1,3-oxadiazole is reacted with propoxyphene to produce highly fluorescent derivatives, thus enabling quantitative determination of propoxyphene in whole blood, urine, or tissue after either therapeutic use or overdose.
Isolation of Drugs and Drug Metabolites from Biological Fluids by Use of Salt-Solvent Pairs
Authors: Horning M G , Gregory P , Nowlin J , Stafford M , Lertratanangkoon K , Butler C , Stillwell W G , Hill R M 
Published: January 2020

Abstract
Simple rapid procedures based on salt-solvent pairs have been developed for the isolation of drugs and drug metabolites from urine, plasma, and breast milk. The best overall recovery of drugs (84-104%) was obtained by using ammonium carbonate—ethyl acetate extraction. Internal standards were added to the biological samples before the isolation procedure was begun; standards labeled with stable isotopes were preferred. The isolated drugs were quantitated by selective ion detection, with use of an LKB 9000-PDP 12 in electron impact mode, a Finnigan 1015-PDP 8/1 in chemical ionization mode, and an atmospheric pressure ionization mass spectrometer. Sensitivity of detection was in the nanogram to picogram range.
Thin-Layer Chromatographic Differentiation of Amphetamine from Other Primary-Amine Drugs in Urine
Authors: Bussey Robert J , Backer Ronald C 
Published: January 2020

Abstract
We describe a thin-layer chromatographic procedure for distinguishing among amphetamine, mescaline, 4-methyl-2,5-dimethoxyamphetamine (STP), 3,4-methylenedioxyamphetamine (MDA), phenylpropanolamine, chlorphentermine, β-phenylethylamine, benzocaine, and procaine. These compounds may be encountered in urine-screening programs, and all except MDA are well separated from amphetamine (a fact not previously established) as well as from each other. They are revealed by sequentially spraying with ethanolic phenylacetaldehyde—ninhydrin and aqueous sodium phosphate. The resulting yellow spots fluoresce green on heating. The aromatic amines fluoresce poorly. MDA is distinguished from amphetamine by overspraying with chromotropic acid. Detection limits and Rf values are reported. Fluorescence spectra of the aliphatic amines are similar.
Radioimmunoassay of Calcitonin in Human Plasma
Authors: Silva Omega L , Snider Richard H , Becker Kenneth L 
Published: January 2020

Abstract
A sensitive, specific radioimmunoassay of calcitonin is described, suitable for measuring the hormone in peripheral plasma of normal man. With this assay we have demonstrated that calcitonin is detectable under ba sal conditions and the concentrations respond to induced and spontaneous hypercalcemia and induced hypocalcemia. The mean value for basal calcitonin of normal men was 182 pg/ml (range 63-450); patients with hypercalcemia of various etiologies had a statistically significant higher mean value of 510 pg/ml (range 110-2700). In calcium-infusion studies, concentrations of both total calcium and ionic calcium correlated well with plasma calcitonin (0.77 and 0.84, respectively). These findings strongly suggest that calcitonin is of physiologic importance in man.
Quantitation of Serum IgG by Solid-Phase Radioimmunoassay
Authors: Cawley Leo P , Goodwin William L , Moeder Marilyn , Dibbern Paulette 
Published: January 2020

Abstract
Human serum immunoglobulins are most frequently measured by single gel diffusion. Radioimmunoassay by use of antibodies bonded to particles is faster and more sensitive, precise, accurate, and specific. We adopted a solid-phase radioimmunoassay (SPRIA) technique, developed in our laboratory, to measure serum IgG, and compared the results with those of a gel-diffusion method commonly used to measure serum IgG. The SPRIA technique is based on competition set up between antibodies to human IgG chemically bonded to cellulose particles and a purified serum IgG labeled with 125I. The solid phase permits prompt separation of the bound from free labeled reagent. We studied precision, accuracy, sensitivity, and specificity, as compared to gel diffusion; values for the two methods agreed well for 57 sera from hospital patients. The SPRIA procedure is more precise, and can be completed in 3 h, as compared to the 16-24 h normally required for gel diffusion procedures. The possible automation of SPRIA is discussed.
Variables in the Laboratory Diagnosis of Fabry's Disease by Measurement of Methylumbelliferyl-α-Galactosidase Activity
Authors: Brewster Marge A , Whaley Steve A , Kane Ann C 
Published: January 2020

Abstract
Assay of methylumbelliferyl-α-galactosidase activity (MUM-α-Galase) in plasma reflects the activity of ceramide trihexosidase and (or) ceramide digalactosidase, which are deficient in Fabry's disease. Intending to institute this assay routinely, we have evaluated substrate stability and concentration, sample stability, heat-inactivation conditions, and normal values. The heat-labile isoenzyme(s) deficient in plasma from patients with Fabry's disease must either be assayed immediately after sampling or the plasma must be stored at or below -50 °C. This heat-labile fraction can be inactivated by incubating a plasma aliquot at 45 °C for 45 min. Normal adult ranges for total and heat-labile MUM-α-Galase are 8.9-31.7 and 7.4-27.4 nmoles of MUM per hour per milliliter of EDTA-treated plasma.
Polymer Enhancement of Automated Immunological Nephelometric Analysis, as Illustrated by Determination of Urinary Albumin
Authors: Lizana Jorge , Hellsing Kristoffer 
Published: January 2020

Abstract
We have developed a new automated immunonephelometric method for determination of albumin in urine, by exploiting the polymer-enhancing effect on the immunological reaction. The original continuous-flow manifold has been simplified and the reaction time shortened to about 3 min. The antiserum was diluted 100-fold in a solution (100 g/liter) of polyethylene glycol (av mol wt, 6000) and mixed with the prediluted sample in the continuous-flow system. The method is highly sensitive and is unaffected by high blank and (or) high absorbance values of the specimens. Day-to-day variation was 3.8-4.3% (CV). Accuracy, as estimated from recovery experiments, was also good. A comparative study of 176 urines with the single radial immunodiffusion technique showed a correlation coefficient of 0.994. We therefore suggest the new method for routine use for determination of urinary albumin, because it is fast, accurate, precise, and sensitive, and requires only small amounts of antiserum.
Column-Chromatographic Analysis of Naturally Fluorescing Compounds: III. Rapid Analysis of Serotonin and Tryptamine
Authors: Chilcote D D 
Published: January 2020

Abstract
A previously described [Clin. Chem. 18, 778 (1972)] chromatographic separation and fluorimetric detection system has been adapted to the determination of serotonin and tryptamine. A strong cation-exchange resin, "Aminex A-6," is used. At a column temperature of 60 °C, serotonin and tryptamine are eluted in 0.5 and 1.0 h, respectively, with an ammonium acetate-acetic acid buffer solution (6 mol of acetate per liter). The sensitivity of the detector allows reliable quantitation of 100 ng of each amine in the sample loaded onto the column.
Protein-Binding Assay for Plasma Testosterone, after Purification by Column Partition Chromatography
Authors: Horgan E D , Riley W J 
Published: January 2020

Abstract
We describe a relatively simple, specific, and practicable method for measuring plasma testosterone by competitive protein-binding analysis. An ether extract is purified by a single chromatographic step on a micro-scale Celite—ethylene glycol column. Serum from women in the third trimester of pregnancy is used as the binding protein, and an ammonium sulfate precipitation step is used to separate the free and protein-bound testosterone. The method has a consistently low blank [0.59 ± 0.26 (SD) pmol/sample] and shows good precision. The mean testosterone concentration in normal men and menstruating women was 17.1 ± 4.0 (SD) and 1.2 ± 0.4 (SD) nmol/liter, respectively.
Gas-Chromatographic Determination of Methylmalonic Acid in Urine and Serum
Authors: Schiller Carol M , Summer George K 
Published: January 2020

Abstract
We describe a gas-chromatographic procedure for determining methylmalonic acid in serum and urine. The sample is acidified and the compound is extracted from it with diethyl ether, derivatized with N,O-bis(trimethylsilyl)trifluoroacetamide, and gas chromatographed. Precision and sensitivity of the method were verified by recovery studies and by comparing the results with those for an established procedure in which ion-exchange column chromatography and colorimetry are used. We analyzed biological fluids from normal individuals and from a patient with methylmalonic aciduria to show that the procedure can be applied to diagnosis of disorders that result in abnormally large amounts of methylmalonic acid in urine and serum.
Clinical Evaluation of Kinetic Enzymatic Fixed-Time and Integral Analysis of Serum Triglycerides
Authors: Tiffany T O , Morton J M , Hall E M , Garrett A S 
Published: January 2020

Abstract
Serum triglycerides can be enzymatically determined by hydrolysis of triglycerides to glycerol and free fatty acids [Clin. Chem. 19, 476 (1973)]. Enzyme integral (end-point) and fixed-time rate analyses of serum triglycerides by this procedure have been investigated with a centrifugal analyzer. We determined the precision of blank determinations, the contribution of normal serum alkaline phosphatase to total values, and the amount of endogenous glycerol in fasting serum samples and blood collection tubes. We also made a statistical analysis of enzymatic triglyceride values obtained for a healthy, fasting (12-16 h) population of men and women. The relative merits of both procedures are discussed.
Automated Fluorometric Creatine Kinase Assay. Measurement of 100-Fold Normal Activity without Serum Dilution
Authors: Armstrong J B , Lowden J A , Sherwin A L 
Published: January 2020

Abstract
Creatine kinase (EC 2.7.3.2) activity can be measured fluorometrically by coupling the reaction product, creatine, to ninhydrin at alkaline pH. We have automated this procedure to develop an accurate and precise method, which requires 0.1 ml of sample and can be performed at 60 tests per hour. By using an abbreviated incubation time and a dialyzer in the assay, we have extended the analytical range to 100 times normal serum activity without sample dilution. The dialyzer also eliminates the nonspecific protein fluorescence of the sample. An additional advantage of the method is the reduced cost of reagents in comparison to similar procedures. Serum blanks should be analyzed whenever serum creatine is abnormally high, especially in cases of severe renal failure.
Improved Assay for Spinal Fluid Glutamine, and Values for Children with Reye's Syndrome
Authors: Glasgow Allen M , Dhiensiri Kamnual 
Published: January 2020

Abstract
We describe a simple assay for spinal fluid glutamine, in which glutaminase is used to deaminate glutamine and the liberated ammonia is then measured with phenol hypochlorite. The concentration of glutamine in spinal fluid is increased in coma of hepatic origin. Spinal fluid glutamine was increased above normal at the time of admission in 20 of 27 cases of Reye's syndrome, of which hepatic dysfunction is apparently a feature. There was no correlation between the initial concentration of glutamine in spinal fluid and the ultimate outcome in these patients.
Immunoglobulin Concentrations in Sera of Normal Children: Quantitation against an International Reference Preparation
Authors: Čejka Jan , Mood Darlene W , Su Kim Chung 
Published: January 2020

Abstract
Immunoglobulins G, A, and M were quantitated in sera from healthy children of various ages by using a standard related to the international reference preparation for human serum immunoglobulins. The results, expressed in International Units per milliliter, provide a basis for the establishment of normal immunoglobulin values in different laboratories.
Rapid Ultraviolet Procedure for Measuring Doxepin and Some Doxepin Metabolites in Human Urine
Authors: Randolph Warren C , Walkenstein Sidney S , Joseph Gerald L , Intoccia Alfred P 
Published: January 2020

Abstract
A method is described for measuring doxepin-related material excreted in urine. Unchanged doxepin and certain doxepin metabolites are oxidized to doxepin ketone with KMnO4. The doxepin ketone is extracted with n-hexane and quantitated by ultraviolet spectrophotometry at the absorption maximum, 266 nm. This method is fast, reproducible, and measures a greater percentage of doxepin-related material than do existing gas—liquid chromatographic procedures. Doxepin ketone was measured to provide bio-availability data, for comparison of different formulations in humans.