bluuebunny/crossref_metadata_2025_split huggingface dataset:
Creepage of Estrogens vs. Loss by Sorption on Glassware
Authors: Kushinsky Stanley , Anderson Marilyn 
Published: January 2020

Abstract
Creepage and decomposition by atmospheric pollutants account for many if not all of the losses that have been attributed previously by others to sorption on glassware. Significant creepage occurs only in uncovered (or incompletely closed) vessels, in the presence of salts and in the absence of proteins (such as gelatin). More creepage occurs in vessels that have been freshly cleaned by treatment with heat, cleaning solution, or organic solvents, when the volume of solution is relatively small compared with the capacity of the vessel and at higher dilutions. In addition, the rate of creepage of intact estrogens is greater than that of the decomposition products. We have found no evidence for sorption of estrogens onto glass from buffered aqueous solutions or decomposition in tightly closed containers in the absence of proteins. Under the conditions we used for silanization, creepage was reduced drastically but not eliminated totally.
Transport of Beta-Carotene in Serum of Individuals with Carotenemia
Authors: Mathews-Roth Micheline M , Gulbrandsen Christian L 
Published: January 2020

Abstract
We studied distribution of carotene in the various serum lipid fractions of carotenemic and noncarotenemic individuals. We found that the amount of carotene in each lipoprotein fraction is increased in the serum from carotenemic individuals, but that the relative increase is significant only in the low-density lipoprotein and high-density lipoprotein fractions. There was no significant difference between the cholesterol concentrations of each fraction of the carotenemic individuals' and noncarotenemic individuals' sera, indicating that serum betalipoprotein is not increased in carotenemia.
Alcohol, Traffic, and Chemical Testing in the United States: A Résumé and Some Remaining Problems
Authors: Mason M F , Dubowski K M 
Published: January 2020

Abstract
We give a résumé of "chemical testing" for alcohol in the United States in connection with traffic-law enforcement. Recent procedural and instrumental developments are briefly reviewed. Various factors involved in discrepancies between the results of analyses of near-simultaneous venous blood and breath specimens from the same subject are examined. Because the causes of these discrepancies cannot adequately be controlled in law-enforcement practice, we suggest that calculation of a blood-alcohol concentration based on the result of a breath analysis be abandoned. We recommend that when breath analysis is performed for law-enforcement purposes, the interpretation of the result should be statutorily based on the amount of alcohol found per unit volume of alveolar ("deep-lung") air. Serum or plasma of capillary blood is recommended as the sample when blood is to be analyzed.
Quantitative Determination of Medazepam, Diazepam, and Nitrazepam in Whole Blood by Flame-Ionization Gas—liquid Chromatography
Authors: Greaves Mavis S 
Published: January 2020

Abstract
Accurate methods are described for the qualitative and quantitative determination of medazepam, diazepam, and nitrazepam in 5 ml of whole blood. Medazepam and diazepam are analyzed intact and nitrazepam is chromatographed as its trimethylsilyl derivative by flame-ionization gas-chromatography on "1% OV-17." A supplementary column of "2% OV-1" is used to separate nitrazepam TMS from diazepam when both are present in the same extract. Essential data given include the percentage recovery of medazepam, and the flame-ionization detector responses of diazepam and silylated nitrazepam relative to medazepam, calculated after extraction from blood and gas-chromatographic analysis. Chromatograms are illustrated of extracts of blood taken from patients on medazepam and diazepam therapy and from a patient who had taken an overdose of nitrazepam.
Rapid Ultramicro Direct Determination of Erythrocyte Lead Concentration by Atomic Absorption Spectrophotometry, with Use of a Graphite-Tube Furnace
Authors: Evenson M A , Pendergast D D 
Published: January 2020

Abstract
We describe a convenient, sensitive, accurate, precise and direct method for lead analysis in blood by use of the graphite-tube furnace with an atomic absorption spectrophotometer. Advantages of this proposed method are the ultramicro sample size and the minimal sample preparation required. Interferences by the major cations and anions in blood were studied and minimized. Anticoagulants examined for matrix effects included heparin, oxalate, and ethylenediaminetetraacetic acid. Potentially serious analytical errors can result if improper sample preparation procedures are adopted in the presence of sodium, potassium, hydroxide and heparin. The surfactant "Triton X-100" did not affect lead absorption. Recovery of lead (calculated as a percentage of the lead added) from human erythrocytes diluted 1:1 with Triton X-100 ranged from 96% to 103% over several days at a wide range of concentrations. On the other hand, recovery of lead added to whole blood, serum, or plasma was always incomplete, independent of the dilution or the diluents used. Quenching effects of sodium, potassium, hydroxide, and heparin were significantly less in whole blood or diluted erythrocytes than in aqueous standards. Absorption was decreased if the standards were not kept at a pH of less than 3. Within-run, the coefficient of variation (CV) was 3.5% at an erythrocyte lead concentration of 0.480 mg/liter of packed cells. The day-to-day CV for the erythrocyte matrix was 7% and 9% at 0.324 and 0.708 mg/liter of packed cells, respectively. When erythrocytes were diluted with an equal volume of Triton X-100 solution and 4 µl of the diluted sample was injected directly into the graphite furnace, no interferences were measured. This graphite-tube furnace method for erythrocytes has high accuracy, excellent precision, extremely high sensitivity, and requires a whole blood sample of less than 10 µl. The normal range for erythrocyte lead concentration (n = 26) was 0.10 to 0.60 mg/liter of packed red cells. This proposed method of lead analysis satisfies all previous criticisms of atomic absorption measurements for lead in blood.
Drug-Abuse and Control Populations Differentiated by a Laboratory Profile
Authors: Mayron Lewis W , Kaplan Ervin , Alling Stearly , Becktel Jack 
Published: January 2020

Abstract
By multivariate analysis of nine laboratory variables, a discriminant function value has been derived that differentiated between a group of 106 drug abusers and a group of 100 normal controls. The variables were serum phosphorus, glucose, lactate dehydrogenase, aspartate aminotransferase, and hematocrit, total leukocyte count, polymorphonuclear leukocyte count, lymphocyte count, and monocyte count. The data demonstrate that the two populations can be distinguished with 4% error in the control group and 14% error in the drug-abuse group. In addition, the individual variables for each group were compared by the t-test. The following were significantly different: serum calcium, phosphorus, blood urea nitrogen, cholesterol, albumin, total bilirubin, alkaline phosphatase, aspartate aminotransferase, and hemoglobin, hematocrit, leukocyte count, polymorphonuclear leukocyte count, stab cell count, and eosinophil count.
New Approach to Derivatization and Gas-Chromatographic Analysis of Barbiturates
Authors: Greeley Richard H 
Published: January 2020

Abstract
A recently developed procedure for alkylation of organic acids has proven extremely successful for preparation of volatile alkyl derivatives of the barbiturates for gas-chromatographic analysis. Soluble salts are formed in a mixture of N,N-dimethylacetamide and methanol. These in turn react rapidly with alkyl iodides to form the corresponding alkyl derivatives. The butyl derivatives of barbiturates, prepared in this manner, are separable by high-resolution gas-chromatography. Any of 14 barbiturates can be determined simultaneously or separately (although there is some overlap with certain uncommon barbiturates). The butyl derivatives of several barbiturates that are unresolved in the form of underived compounds or methyl esters can be resolved, thus overcoming many previous analytical limitations.
Gas-Chromatographic Simultaneous Analysis for Glutethimide and an Active Hydroxylated Metabolite in Tissues, Plasma, and Urine
Authors: Hansen Alfred R , Fischer L J 
Published: January 2020

Abstract
We report a gas-chromatographic method for the simultaneous quantitative analysis of both glutethimide and 4-hydroxy-2-ethyl-2-phenylglutarimide (4- HG), an active metabolite of glutethimide, in tissues, plasma, and urine. The method, applied to postmortem tissues from cases of fatal glutethimide overdose and to plasma samples obtained from a patient in coma from acute glutethimide intoxication, proved to be accurate, sensitive, and specific. Results of the analysis confirm that 4-HG accumulates in plasma and tissues during glutethimide intoxication. Because 4-HG has been shown previously to be at least as potent as glutethimide itself, its accumulation may play an important role in the acute toxicity of glutethimide.
Evaluation of Immunoassay Methods for Detection, in Urine, of Drugs Subject to Abuse
Authors: Mulé S J , Bastos M L , Jukofsky D 
Published: January 2020

Abstract
Results for abused drugs in urine, as obtained by radioimmunoassay (RIA), the "Enzyme Multiplied Immunoassay Technique" ("EMIT"), and hemagglutination inhibition (HI), were compared with each other, with fluorimetry, and with thin-layer chromatography (TLC). The immunoassays and fluorimetric methods were highly sensitive (30 µg/liter to 2 mg/ liter). Cross-reactivity (lack of specificity) varied with the method tested and the drug, ranging from no reaction to one exceeding that of the assay drug. The percentage of false positives for the immunoassays in comparison to TLC ranged from 3 to 31. The practical level of sensitivity for TLC, however, was only 1-5 mg/liter. False negatives were less than 2%. With the EMIT system (for those drug assays for which it is used), the total percentage of false values (negative and positive) ranged from 5 to 13. All the immunoassays were reliable within the limitations of the assay, relatively easy to use, did not require sample treatment, and several hundred samples could be analyzed during an 8-h period; but the cost was moderate to high, depending upon assay or sample volume. Judicious use of immunochemistry, spectrofluorimetry, and thin-layer chromatography to the detection of psychoactive drugs in urine permits rapid, reliable, and effective surveillance of drug use or abuse.
Qualitative and Quantitative Determination of Methaqualone in Serum by Gas Chromatography
Authors: Evenson M A , Lensmeyer G L 
Published: January 2020

Abstract
A rapid, simple, accurate, and precise isothermal gas-chromatographic method is introduced for determination of methaqualone (2-methyl-3-o-tolyl-4(3H)-quinazolinone) in serum. A single extraction of 2 ml of serum, without derivative formation, will give adequate sensitivity for quantitation of therapeutic serum concentrations of the drug within 15 min. The method is free of interferences from biological substances, as well as from commonly used drugs. A non-drug internal standard compensates for variables in extraction, injection, and instrumental changes during analysis. The coefficient of variation, day-to-day, is 5.6%. Mean recovery of added methaqualone was 80%. To compensate for the nonquantitative yield and ensure accurate results, we prepared all analytical methaqualone standards in serum.
Routine Use of a Flexible Gas Chromatograph—Mass Spectrometer—Computer System to Identify Drugs and Their Metabolites in Body Fluids of Overdose Victims
Authors: Costello C E , Hertz H S , Sakai T , Biemann K 
Published: January 2020

Abstract
We have assembled a computer-searchable collection of 300 mass spectra of drugs, metabolites, normal body-fluid constituents, and common sample contaminants, for use in conjunction with a gas chromatograph—low resolution mass spectrometer system. The system is designed for analysis of drugs in body fluids of comatose victims of accidental or deliberate ingestion of a drug overdose. The speed and generality of the method make it particularly useful for such emergency situations. It has now been in routine use for longer than two years, and its usefulness is illustrated by results obtained for several actual samples.
Modification of an Automated Method for Measurement of Sulfamethoxazole and Its Major Metabolite in Biological Fluids
Authors: Bye Alan , Fox Anthony F J 
Published: January 2020

Abstract
Mechanization of the Bratton and Marshall procedure for the analysis of sulfonamides in biological fluids usually incorporated a dialysis step. Results for sulfamethoxazole and its major metabolite (N4-acetylsulfamethoxazole) by the traditional method of acid hydrolysis often showed "negative" quantities of the metabolite. After an exhaustive examination it was found that the dialysis step must be rigorously controlled and for most laboratory applications it was better to omit the dialysis, when removal of protein and dilution of samples and standards outside the mechanized system was necessary. Reasons for the dialysis omission are discussed.
Biological Aspects of Breath-Alcohol Analysis
Authors: Dubowski Kurt M 
Published: January 2020

Abstract
We studied several relevant biological aspects of breath-alcohol analysis in 55 healthy men and women, after alcohol ingestion and during breath-alcohol analysis with a typical 4th-generation instrument. We measured breath volumes, delivery pressures, and end-expiratory temperatures, with the following findings: End-expiratory temperature, 32.41-35.69 °C (mean, 34.53 °C); forced vital capacity, 1825-6550 ml (mean, 4038 ml); maximum expiration after normal inspiration, 1180-4550 ml ( mean, 2730 ml); breath delivery pressure into a prototype Borg-Warner Model P-7 breath-alcohol apparatus, 8-50 inches H2O (mean, 21.3). These data and other pertinent findings from this study should assist in more rational design of breath-sampling systems in forthcoming breath-alcohol instruments and in developing valid procedures for their use.
Technique for Rapidly Separating Drugs from Biological Samples
Authors: Aggarwal Vijay , Bath Raymond , Sunshine Irving 
Published: January 2020

Abstract
With use of a sample/solvent ratio of 8.5 ml to 100 µl, certain drugs may be extracted efficiently from urine that has been saturated with a solid buffer. An aliquot of this extract may be injected directly into a gas chromatograph. We show how this procedure is applied to confirmation of some drugs of abuse.
Enhancing Effect of Glutamate on Apparent Serum γ-Glutamyltranspeptidase Activity
Authors: Bondar Richard J L , Moss Gerald A 
Published: January 2020

Abstract
Free glutamate increases the apparent serum γ-glutamyltranspeptidase (γ-GTP) activity in the normal range by 100%, and in the 10-fold normal range by 20%. This increase is greatest, and is the same, at two very different concentrations, 60 and 1000 µmol of glutamate per liter of the final reaction mixture. Glutamate concentrations greater than 10 mmol/liter inhibit serum γ-GTP. Elevated serum glutamate concentrations or glutamate released by substrate breakdown will therefore give false and possibly variable results. To minimize variations in activity, the assay should be run in the presence of 1.0 mmol of glutamate per liter. This concentration, which is 100 times greater than that which normal serum would contribute (with respect to free glutamate) to the assay system, thus masks any effect of extraneous glutamate.
Automated Simultaneous Determination of p-Aminohippurate and Creatinine in Plasma or Urine
Authors: Parekh C K , Kirpan J , Peterson A , Hassert G L , Murphy B F 
Published: January 2020

Abstract
Methods have been developed for using the Beckman "Discrete Sample Analyzer" (DSA-560), for automated simultaneous determinations of p-aminohippurate (PAH) and creatinine in the same 50- or 10-µl samples of plasma or urine, respectively, at the rate of 80 samples per hour. In determinations of PAH, a single reagent, p-dimethylaminocinnamaldehyde in 0.1 mol/liter HCl, was added to a protein-free filtrate from plasma or urine. The intensity of the color, measured at 550 nm, obeyed Beer’s law for PAH concentrations from 0.005 to 5.0 g/liter. Data obtained for the same plasma and urine samples by the manual method, were, in general, within ±5% of the results obtained by the automated method. Creatinine was simultaneously determined by adapting the method of Taussky to the DSA-560 instrument; the intensity of the color, measured at 510 nm, obeyed Beer's law for creatinine concentrations ranging from 0.005 to 5.0 g/liter. Data obtained for the same plasma and urine samples by the manual method, were, in general, within ± 5% of the results obtained by the automated method.
Assay of Aspartate Aminotransferase Activity: Effects of Serum and Serum Proteins on Oxalacetate Decarboxylation and Dialysis
Authors: Rej Robert , Vanderlinde Raymond E 
Published: January 2020

Abstract
Effects of serum and protein on assays measuring aspartate aminotransferase (L-aspartate:2-oxoglutarate aminotransferase, EC 2.6.1.1) were examined. Increasing amounts of normal human serum or human serum albumin in samples with fixed amounts of purified enzyme decrease absorbance values and thus distort the results obtained in an assay in which diazonium-salt chromogenic reagent is used. Serum also directly accelerates disappearance of oxalacetate from an incubation medium similar to that of the enzyme assay studied. Protein accelerates spontaneous decarboxylation of oxalacetate to pyruvate, preventing its quantitation in assays specific for oxalacetate. Primary amine groups of protein are evidently involved, because acylated albumin does not accelerate decarboxylation. This effect is not attributable to metal ions in serum and is not significant in procedures involving use of the less specific dinitrophenylhydrazine, which measure the decarboxylation product, pyruvate. Continuous kinetic assays of aspartate aminotransferase activity, in which oxalacetate is not allowed to accumulate, are unaffected by protein concentration. Fivefold dilution of patients’ sera with physiological saline results in activities that are artifactually high by 56% in affected assays. Varying oxalacetate decarboxylation is also a source of error in the estimation of malate dehydrogenase (L-malate:NAD oxidoreductase; EC 1.1.1.37) activity in body fluids. Protein increases the values obtained by automated procedures requiring dialysis by increasing the amount of oxalacetate diffusing into the chromogenic flow stream. A solution of albumin, about 6 g/dl, is suggested as a dilution fluid for use with the affected assays.
Rapid Gas—Liquid Chromatographic Determination of Carbamazepine in Plasma
Authors: Perchalski Robert J , Wilder B J 
Published: January 2020

Abstract
A rapid, sensitive method is described for the quantitative determination of carbamazepine in plasma. The coefficient of variation of replicate extractions is typically within 5%. This procedure can be completed in 45 min and the derivatives formed by the reaction of the drug and internal standard with dimethylformamide dimethyl acetal are stable for at least 17 h. The lower limit of detection is 0.2 µg/ml of plasma.
Necessity of Prerinsing Disposable Polypropylene Pipet Tips
Authors: Zeman G H , Mathewson N S 
Published: January 2020

Abstract
Errors as great as 15% of rated volume occurred in the first sample dispensed from a piston-actuated microliter pipet when disposable polypropylene tips were used. We recommend prerinsing the tip before it is used to dispense either aqueous or nonaqueous solutions, to obviate these possible errors.
Automated Determination of Serum Hexosaminidase A by pH Inactivation for Detection of Tay-Sachs Disease Heterozygotes
Authors: Saifer Abraham , Perle Guta 
Published: January 2020

Abstract
We have automated a manual test for detection of heterozygotes of Tay-Sachs disease by assay of hexosaminidase A in serum, based on pH inactivation [Clin. Chim. Acta 43, 417 (1973)]. The same manifold is used both for the total hexosaminidase and pH-inactivation (hexosaminidase B) procedures. Automation expedites mass screening of the Ashkenazi Jewish population for carriers of the Tay-Sachs gene (prevalence rate, 1:30), because 100 or more tests can be performed daily. The mean percentage value and range (±2 SD) of hexosaminidase A for normal adults is 68.6 (58-79) and for carriers is 48.8 (39-59) with the automated pH-inactivation procedure. "Presumed carriers" (&lt;53% hexosaminidase A) and individuals in the uncertain range (53 to 58%) should be retested by using leukocytes, to avoid the effect of certain physical ailments, before being labeled as carriers. The same automated system used for this assay can also be used to detect carriers of at least seven other sphingolipidoses for which artificial fluorogenic substrates are available.
Standardization in Abnormal Hemoglobin Detection. An Evaluation of Hemoglobin Electrophoresis Kits
Authors: Schmidt Robert M , Holland Solomon 
Published: January 2020

Abstract
Three widely used commercial hemoglobin electrophoresis kits were studied to ascertain specificity, accuracy, precision, and characteristics of product information. Two hundred and ninety-six hemoglobin samples were used to evaluate each kit. Except for poor separation of hemoglobin F by one kit, all three kits gave generally satisfactory results. We give specific recommendations for improving these kits and for laboratory quality-control practices.
Interference with Measurement of 3-Methoxy-4-hydroxymandelic Acid and 5-Hydroxyindoleacetic Acid by Reducing Metabolites
Authors: Feldman Jerome M , Butler Susan S , Chapman Barbara A 
Published: January 2020

Abstract
Using standard analytical techniques, we noted a decrease in the urinary excretion of 3-methoxy-4-hydroxymandelic acid and 5-hydroxyindoleacetic acid in a patient with alcaptonuria, and in subjects receiving aspirin or L-dopa [3-( 3,4-dihydroxyphenyl)-L-alanine]. This apparent decrease in excretion of the two compounds is an artifact produced by metabolites in urine, such as homogentisic acid, gentisic acid, 3,4-dihydroxyphenylacetic acid, or homovanillic acid.
Mass Phenotyping of Isoniazid Inactivators by Automated Determination of Acetylisoniazid in Urine
Authors: Varughese P , Hamilton E J , Eidus L 
Published: January 2020

Abstract
An automated procedure is described for phenotyping isoniazid inactivators. The method is based on the color reaction produced by N-acetylisoniazid in aqueous solution, as described by Eidus and Hamilton [Amer. Rev. Resp. Dis. 89, 587 (1964)]. Maximum sampling rate is 60 samples per hour. Results of this procedure correlated well (r = 0.987) with those of a manual phenotyping method.
Characterization of the Periodate Oxidation of Glycerol and Related Compounds, and Application toward Determination of Serum Triglyceride Concentrations
Authors: White D A , Miyada,1 D S , Nakamura R M 
Published: January 2020

Abstract
The periodate oxidation of glycerol was examined to see if it could be quantitated from its yield of an equimolar amount of formaldehyde. End-product studies, carried out with glycerol and related compounds by an automated method, indicated that oxidation was almost completed within the time span of the analysis. Kinetic studies at pH 4.0 with excess substrate indicated pseudo-first-order kinetics with respect to periodate consumption. The rate constant for glycerol is 57 x 10-2 min-1; the reaction with glycolaldehyde was too rapid to measure. These results indicate that it is the initial reaction of periodate with glycerol that is rate-limiting instead of the secondary reaction with glycolaldehyde, and that these reactions occur concomitantly. We conclude that it is extremely unlikely that any practicable glycerol analysis can be based on the equimolar formation of formaldehyde.