bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantitative Determination of Medazepam, Diazepam, and Nitrazepam in Whole Blood by Flame-Ionization Gas—liquid Chromatography
Authors: Greaves Mavis S
Published: January 2020

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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" (<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

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

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

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

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.
Comparison of Five Methods for Determination of 2,3-Diphosphoglycerate in Blood
Authors: Teunissen A J , de Leeuw R J M , Boink A B T J , Hamelink M L , Maas A H J
Published: January 2020

Because the importance of 2,3-diphosphoglycerate in the regulation of the oxygen affinity of hemoglobin is recognized, there is growing need for a suitable method for determining this metabolite. Here we compare the colorimetric method of de Leeuw, two enzymatic rate-dependent methods (of Nygaard and Rörth and of Loos and Prins), and two enzymatic end-point methods (of Keitt and of Ericson and de Verdier). A good linearity was observed for all methods, up to 5.0 mmol of 2,3-diphosphoglycerate per liter of blood, except for the method of Ericson and de Verdier, for which an inexplicable upward drift in the calibration curve was found. Within-run precision in the duplicates and long-term precision in the methods of Loos and Prins and of de Leeuw were excellent. Mean analytical recoveries for all the methods ranged from 97 to 100%. In a paired comparison study of the methods, with the method of Loos and Prins as a reference, we did not find statistically significant differences. Coefficients of correlation were better than 0.990 (P < 0.0005).
Use of the Simplex Method to Optimize Analytical Conditions in Clinical Chemistry
Authors: Krause Richard D , Lott John A
Published: January 2020

The optimum analytical conditions with regard to two or more variables can be determined in an unambiguous way by use of the simplex method. The method is particularly applicable to problems involving interacting variables. We describe the application of the simplex technique to the optimization of two procedures on a continuous-flow analyzer (AutoAnalyzer) and to the optimization of chemical variables in the lactate dehydrogenase-catalyzed pyruvate-to-lactate reaction and certain instrumental variables on a centrifugal analyzer (the ENI-GEMSAEC).
Mechanisms of the Liebermann-Burchard and Zak Color Reactions for Cholesterol
Authors: Burke R W , Diamondstone B I , Velapoldi R A , Menis O
Published: January 2020

Correlation of SO2 and Fe2+ measurements with new spectral data indicates that the Liebermann-Burchard (L-B) and Zak color reactions for cholesterol have similar oxidative mechanisms, each yielding, as oxidation products, a homologous series of conjugated cholestapolyenes. These studies further suggest that the colored species observed in these two systems are enylic carbonium ions formed by protonation of the parent polyenes. Thus, the red (λmax, 563 nm) product typically measured in the Zak reaction is evidently a cholestatetraenylic cation, and the blue-green product in the L-B reaction (λmax, near 620 nm) is evidently the pentaenylic cation. The effects of rate of carbonium ion formation and sulfuric acid concentration on sensitivity and color stability are discussed. A solvent extraction procedure is described for specifically converting cholesterol to 3,5-cholestadiene. Incorporating this step into the typical L-B method can increase the L-B sensitivity for cholesterol by several fold.
Spectral Interpretation and Kinetic Studies of the Fe3+-H2SO4 (Zak) Procedure for Determination of Cholesterol
Authors: Velapoldi R A , Diamondstone B I , Burke R W
Published: January 2020

Spectral changes and kinetic data presented for the Zak reaction show the pseudo-first-order character of the consecutive oxidative reactions undergone by cholesterol and selected steroid dienes. These data give excellent support to the proposed formation of the homologous series of steroidal enylic cations which are the absorbing species in the spectrophotometric cholesterol determination. Typical thermodynamic quantities of ΔG‡, ΔH‡, ΔS‡ and Ea are also reported for several different reactions. Low acetic-sulfuric acid ratios evidently result in the stabilization of the lower members of the homologous enylic series. Although excellent reproducibilities are obtained for premixed and non-premixed Zak reagents, it is necessary to use the premixed reagent if good temperature control is required, as would be the case for kinetic methods of analysis run under the conditions we used. The isosbestic point observed at 503 nm may also be used as an analytical wavelength because it is less sensitive to variables such as temperature, time, and steroid concentration.
Gas-Chromatographic Determination of Ethylene Glycol in Serum
Authors: Peterson R L , Rodgerson D O
Published: January 2020

We have developed a method for detection and quantitation of ethylene glycol in serum, based on the gas chromatography of its dibenzoate ester. No special reagents or equipment are required. The method is virtually free of interference and sensitive to less than 0.02 mg of ethylene glycol per milliliter. The total analysis time is about 90 min.
Refinement and Critical Evaluation of a Fluorometric Method for Measuring Leucine Aminopeptidase Activity in Serum or Tissues
Authors: Uete Tetsuo , Shimano Noriko , Shimizu Shuko
Published: January 2020

The fluorometric method for measuring leucine aminopeptidase (EC 3.4.11.1) activity in biological systems, with L-leucyl-β-naphthylamide as the substrate [Clin. Chem. 16, 412 (1970)] was critically evaluated and refined. In this enzyme assay system, a few precautions are necessary in determining β-naphthylamine liberated from the substrate by the enzyme action. In water, tris(hydroxymethyl) aminomethane buffer, and ethanol, β-naphthylamine, excited at 280 nm, fluoresces at 400 nm with a greater intensity than when an excitation wavelength of 340 nm is used. However, in the presence of protein or substrate the fluorescence intensity with an excitation wavelength of 280 nm is markedly diminished, and is less intense than that with 340 nm. Therefore, an excitation wavelength of 340 nm is preferred to 280 nm, to obtain increased sensitivity. Bilirubin and hemoglobin also slightly diminish the fluorescence intensity.
A Small Portable Centrifugal Fast Analyzer System
Authors: Scott Charles D , Burtis Carl A , Johnson Wayne F , Thacker Louis H , Tiffany Thomas O
Published: January 2020

The recent development of minature fast analyzer systems based on the GeMSAEC principle, coupled with the possibility of direct introduction of unprocessed liquid samples, has been further extended to include a very small analytical system that is inexpensive, battery-operated, and portable. The basic analyzer is included in and on a cabinet, about 10 x 10 x 10 cm, and a coupled data-processor records analytical data in absorbance units and in arbitrary fluorescence units. The system is compatible with up to seven simultaneous colorimetric or fluorometric assays on physiologic fluids. The dynamic mode of sample loading is used, and the system is compatible with the introduction of unprocessed whole blood. End-point or rate analysis is possible, and the coefficient of variation obtained in multichemistry tests on a single serum sample introduced dynamically is comparable to that obtained with larger Centrifugal Fast Analyzer systems.
Immobilized Glucose Oxidase Used to Measure Glucose in Serum
Authors: Kunz Hans J , Stastny Milos
Published: January 2020

We report an analytical system in which glucose oxidase immobilized on controlled-pore glass is used. The immobilized glucose oxidase was packed in a column that was part of a continuous-flow system. Oxygen depletion of the buffer was measured with a Clark-type electrode, and the resulting data were stored on tape and then evaluated with a PDP-12 computer. The relative advantages of several measurement approaches are given: (a) an endpoint method for prediluted sample, (b) an endpoint method for discrete, undiluted 9-µl samples, and (c) a maximum reaction rate measurement with discrete, undiluted samples. Catalase and mutarotase interferences were considered and found insignificant under the conditions chosen. The effects of protein, fluoride, and oxalate were determined. The column can be re-used for at least 1000 samples. Useful storage life of the immobilized glucose oxidase preparation, measured at intervals during a year, exceeded one year at room temperature.
Xanthine Oxidase Deficiency: Studies of a Previously Unreported Case
Authors: Holmes Edward W , Mason David H , Goldstein Leonard I , Blount Robert E , Kelley William N
Published: January 2020

Xanthinuria is a familial disorder of purine metabolism that results from a marked deficiency of xanthine oxidase (EC 1.2.3.2) activity. We report here the clinical and biochemical features of a new case of xanthinuria. Serum urate concentration was 0.8 mg/100 ml, urinary uric acid excretion was 16 mg per day, urinary oxypurine excretion was 1630 µmol per day, and total purine excretion was 314 mg per day. After allopurinol was administered, total purine excretion was 323 mg per day and erythrocyte phosphoribosylpyrophosphate content was unchanged. The ratio (by wt) of xanthine to hypoxanthine in the urine was 4.6 before and 9.6 after allopurinol was administered to this patient. Both allopurinol and oxipurinol were detectable in urine. Orotic acid and orotidine excretion increased from undetectable amounts (<2 mg per day) to 47 and 86 mg per day, respectively. These data suggest that this xanthinuric subject has a markedly decreased xanthine oxidase activity, although some residual activity may be functional in vivo. It is probable that he re-utilizes purine so extensively that hypoxanthine phosphoribosyltransferase (EC 2.4.2.8) is virtually saturated with hypoxanthine and xanthine in vivo. In addition, these data indicate that the increase in orotic acid and orotidine seen in normal and gouty subjects taking allopurinol is not a direct consequence of xanthine oxidase inhibition, but probably an effect of allopurinol or one of its metabolites on pyrimidine biosynthesis.
Automated Procedure for Determination of Sialic Acids and 2-Deoxyribose in Blood and Tissues
Authors: Engen R L , Anderson A , Rouze L L
Published: January 2020

A manual procedure for measuring sialic acids in blood and tissue and an automated procedure for measuring sialic acids in blood have been combined and modified so that sialic acid concentrations in both blood and tissue can be determined by continuous-flow analysis. Because 2-deoxyribose interferes with tissue sialic acid determinations, there must be a correction for color produced by it. In the calculation of sialic acids, the value for 2-deoxyribose can simultaneously be obtained. In addition to the analyses of mixed standards of sialic acids and 2-deoxyribose, we report analytical data for rat blood and tissue samples.
Manganese, Copper, and Zinc Concentrations in Serum and Packed Blood Cells during Acute Hepatitis, Chronic Hepatitis, and Posthepatitic Cirrhosis
Authors: Versieck Jacques , Barbier Fabrice , Speecke Albert , Hoste Julien
Published: January 2020

Manganese, copper, and zinc concentrations were determined in serum and packed blood cells of normal controls, patients with acute and chronic (persistent or aggressive) hepatitis, and cases of postnecrotic cirrhosis. During the active phase of acute hepatitis, serum manganese concentrations are invariably increased; the difference between the mean value and the normal is highly significant, P < 0.001. The mean serum copper is also significantly increased (P < 0.01). The concentrations become normal during the subsiding phase. In chronic aggressive hepatitis and posthepatitic cirrhosis, the mean serum manganese concentration is increased, P < 0.001, whereas the serum zinc concentration is frequently decreased. There is a highly significant (P < 0.001) positive correlation between serum manganese concentration and the activity in serum of aminotransferases, in subjects with acute or chronic hepatitis or postnecrotic cirrhosis.
Values for Urinary Excretion of D-Glucaric Acid by Normal Individuals
Authors: March James , Turner William J , Shanley Josette , Field John
Published: January 2020

The urinary excretion of D-glucaric acid reflects the activity of hepatic enzymes that hydroxylate and detoxify many substances foreign to the body. We measured it in 38 healthy unmedicated males (ages, 3 to 90 years; weights 11.8 to 136 kg) and in 15 females (ages, 10 to 80). The males, regardless of age or weight, excreted 56.1 ± 15.7 (SD) nmol of D-glucaric acid per milligram of creatinine. A "standard man" would excrete 98 µmol of this compound per day, in agreement with observations by other workers. We infer that the normal hydroxylating activity of the liver is a direct function of body cell mass.
One-Hour Radioimmunoassay of Serum Drug Concentrations, as Exemplified by Digoxin and Gentamicin
Authors: Berk Lee S , Lewis John L , Nelson Jerald C
Published: January 2020

Double-antibody radioimmunoassays in which tritium is used for labeling have been adapted for emergency determinations of serum drug concentrations. In the cases of digoxin and gentamicin, the first and second antibody incubations may be carried on simultaneously, minimizing incubation times (10 and 27 min, respectively). Counting the bound radioactivity in solubilized immunospecific precipitates decreases variability in the composition of the phase counted and markedly decreases problems of quenching and chemiluminescence. Logitlog transformation of the sigmoidal standard curve results in a straight line, which can be described by its slope and intercept and which remains constant if assay conditions and critical reagents are held constant. Because the slope and intercept of the standard curve are characteristic of a given assay system, it is possible to calculate the theoretical standard curve for a specific assay system by using the means of previously observed slopes and intercepts. Thus, a separate standard curve need not be prepared for each subsequent assay run. Total time required for drug determinations is now less than 1 h. When unknown samples were measured by both the conventional radioimmunoassay method and the new rapid radioimmunoassay method, the values correlated well (r = 0.99) for both digoxin and gentamicin.
Manual Immunonephelometric Assay of Proteins, with Use of Polymer Enhancement
Authors: Lizana Jorge , Hellsing Kristoffer
Published: January 2020

A manual immunonephelometric method for proteins has been developed by using an ordinary fluorometer as a nephelometer. By applying the enhancing effect of polyethylene glycol (av mol wt, 6000) on the immunological reaction, albumin and fibrinogen were quantitated after a 10-min reaction time. Under the present conditions the sensitivity was increased and thus antiserum consumption was decreased. The reaction conditions were carefully studied with respect to optimal time and concentration of the reactants. The precision of the method was 2.6-3.6% (CV). The lower detection limit in the albumin-antialbumin system was 0.1 mg/liter. Comparative studies showed a correlation coefficient of 0.991 with an automated immunonephelometric method for urinary albumin, and of 0.908 with a thrombin clottable method for plasma fibrinogen. We especially suggest use of this manual immunonephelometric method where small series of samples are to be analyzed.
Use of Control Sera for Monitoring Temperature Changes during pH and PCO2 Measurements
Authors: Manning John P , Sasaki Daniel N , Wertlake Paul T
Published: January 2020

We evaluated the temperature coefficients from 25 to 38 °C for aqueous calibration materials, serum (protein-based) control material, and patients’ samples in blood pH measurements and gas analysis. Whereas the aqueous buffers and calibration gases (used as unknowns) were not affected by changing temperature, the temperature coefficients of patients’ samples and protein-based control materials varied similarly to those reported in the literature: 0.011 and 0.014 vs. 0.015 pH/ °C, and 1.76 and 1.57 vs. 1.80 mm Hg/°C. We conclude that the periodic use of suitable control materials can assist in the detection of temperature abnormalities.
Automated Enzymatic Micromethod for Determination of Uric Acid in Serum and Urine with a Centrifugal Analyzer
Authors: Pesce Michael A , Bodourian Selma H , Nicholson John F
Published: January 2020

Uric acid is determined in serum and urine by an enzymatic method on a centrifugal analyzer. The sample (8 µl) is mixed with the enzyme uricase in a sodium borate buffer. The resulting decrease in absorbance at 292 nm is linearly proportional to the concentration of uric acid from 1 to 75 mg of uric acid per deciliter. Use of a centrifugal analyzer eliminates measurement of a separate serum blank. Recovery of uric acid added to serum and urine averaged 100% (range: 97-110%). Within-run precision (CV) on a serum pool for which the mean value was 5.96 mg/dl was 2.52%; day-to-day precision, measured on the same serum pool over a seven-day period, was 2.81% (mean: 6.05 mg/dl). Results obtained for serum with the uricase method on a centrifugal analyzer and with the uricase method on the Du Pont aca yielded a correlation coefficient of 0.99.
Quantitative Gas-Chromatographic Determination of Short-Chain Fatty Acids in Aqueous Samples
Authors: Collin Dennis P , McCormick Patrick G , Schmitt Milton G
Published: January 2020

We report the use of SP-1200 (Supelco Inc.) for quantitative gas-chromatographic determination of short-chain fatty acids (C2-C5) in stool water. The ratio of peak areas for these acids to that for 2-methylvaleric acid (internal standard) is linear for each acid from 60 to 1800 mg/liter. Lactic acid, occasionally present in stool in abnormally high amounts, is not detectable as the free acid on SP-1200, but is determined as its propyl ester on diethyleneglycolsuccinate.
Determination of L-Tyrosine as Tyramine in Urine
Authors: Tashian Richard E
Published: January 2020

A procedure for the determination of l-tyrosine in human urine is described. Tyrosine is converted to tyramine by treating it with the decarboxylase present in an acetone-powder preparation of S. faecalis. The tyramine is then separated from the urine and assayed by the nitrosonaphthol method. Examples of the application of this technic to human urine are presented.
On the Determination of "Pancreatitis Lipase" in serum
Authors: Henry Richard J , Sobel Charles , Berkman Sam
Published: January 2020

The specificity of the lipolytic activity occurring in sera from patients with acute pancreatitis for olive oil has been demonstrated. The "lipase" method proposed by Goldstein and co-workers, employing tributyrin as substrate, does not measure "pancreatitis lipase" "Pancreatitis lipase" differs from the enzymes present in pancreatic extracts so that, if the former is the subject of concern in experimental studies, sera from patients with pancreatitis must be used as the source of the enzyme.

Several variables involved in the use of olive oil as substrate have been examined, and the technic finally arrived at is essentially that proposed by Cherry and Crandall with the exception of the use of thymolphthalein as indicator in the titration. Normal values for this technic were determined.
Comparison of the Archibald-Kern and Stransky Colorimetric Procedure and the Praetorius Enzymatic Procedure for the Determination of Uric Acid
Authors: Alper Carl , Seitchik Joseph
Published: January 2020

The Archibald modification of the Kern and Stransky procedure for uric acid has been studied and its efficacy for routine use in clinical chemistry evaluated. Mean values and the range of values for men and women have been determined.
Micro Determination of Cholesterol by Use of 0.04 Ml. of Blood Serum
Authors: Galloway Leora S , Nielson Patricia W , Wilcox Ethelwyn B , Lantz Edith M
Published: January 2020

A micro method for cholesterol determination adapted from the macro method of Sperry and Webb is described with comparisons of results obtained by the two methods. In general, the two methods gave similar results for free and total cholesterol.
Urinary Sulfur Partition in Normal Men and in Cancer Patients
Authors: Papadopoulou Daphne B
Published: January 2020

1. The partition of inorganic and total sulfate and total and neutral sulfur has been estimated in 10 normal men and 27 cancer patients.

2. The excretion of inorganic and total sulfate was found to be decreased and the neutral sulfur fraction increased in cancer patients more than in the normal subjects.

3. From the data above, it is suggested that there may be a decrease in the rate of the intracellular oxidation substances in the body of cancer patients.
Human Serum Bilirubin
Authors: O'Hagan J E , Hamilton Teresa , Le Breton E G , Shaw A E
Published: January 2020

The technic of Powell (3) for the estimation of serum bilirubin has been modified by reading the optical density of the solutions shortly after mixing the reagents and using a standard based on a more appropriate solution of crystalline bilirubin in pigment-free serum.

Seven specimens of bilirubin were examined spectrophotometric-ally; the disproportionality of the millimolar extinction coefficients at 453 mµ for the free-bilirubin and at 532 mµ for, the azobilirubin complex indicated the presence of an unreactive yellow pigment.

The destructive effect of sunlight on solutions of biirubin, noted in the literature, was confirmed, hence all estimations were done without delay or exposure to light for any length of time. The results obtained on apparently healthy blood donors, to detect possible carriers of homologous serum hepatitis, revealed no definite correlation between previous history of jaundice and increased serum bilirubin values, but as a precautionary measure individuals with values above 1.5 mg. per 100 ml. were not accepted as donors.

When 200 random values were plotted, the distribution curves gave a mean value higher for males than females. Furthermore, 108 donors (among the 25,000 screened) had biirubin values greater than 1.5 mg. per 100 ml. The eleven females of the group did not maintain high values, while 30 males recorded high values on more than one occasion, some consistently.

No significant correlation was found between high bilirubin values and a previous history of jaundice, nor were any cases of posttrans-fusion hepatitis traced to these donors. Somewhat arbitrarily, 1.5 mg. per 100 ml. was chosen as the upper limit of normal.
Practical Evaluation of Acid-Base Balance
Authors: Jacobi Herbert P , Barak Anthony J , Beber Meyer
Published: January 2020

The Co2 combining power bears a variable relationship to the in vivo plasma bicarbonate concentration, depending upon the type and severity of acid-base distortion. In respiratory alkalosis and metabolic acidosis the Co2 combining power will usually be greater than the in vivo plasma bicarbonate concentration; whereas, in respiratory acidosis and metabolic alkalosis the Co2 combining power will usually be less. Co2 content, on the other hand, will always parallel the in vivo plasma bicarbonate concentration quite closely, being only slightly greater. These facts, together with other considerations which are discussed, recommend the abandonment of the determination of CO2 combining power.
Improved Method for the Colorimetric Determination of Glutamic-Oxalacetic Transaminase Activity
Authors: Humoller Fred L , Holthaus Joseph M , Walsh John R
Published: January 2020

A modification of the Cabaud et at. method (1) for the determination of SGOT activity is described. The proposed modification consists of the elimination of the interference of unreacted DNPH by extracting the pyruvate dinitrophenyihydrazone with aqueous bicarbonate. The proposed method also employs a lower concentration of alpha-ketoglutarate, thus reducing its competition for the available DNPH.
Absorbance of Various Protein-Free Filtrates of Serum
Authors: Henry Richard J , Berkman Sam
Published: January 2020

Absorbance curves have been run on protein-free serum filtrates obtained with trichloroacetic acid, tungstic acid, and zinc hydroxide. The background absorbance was highest in trichloroacetic acid filtrates, lowest in zinc hydroxide filtrates, and increased with decreasing wavelength. The possible error produced in photometric determinations by this nonspecific absorbance and means of correction have been discussed.
Enzymes in Clinical Biochemistry
Authors: King E J
Published: January 2020

In the paper by E. J. King in the Supplement to the August, 1957, issue of CLINICAL CHEMISTRY (Vol.3, No.4, Part Two), pages 510 and 511 do not appear. This is due to an error in pagination only, and the text is complete and in proper order. In the same paper, the insert consisting of Figs. 1 and 5, which should have appeared between pages 508 and 509, was incorrectly placed and will be found between pages 546 and 547.
Determination of Plasma Amine Oxidase Activity
Authors: Humoller Fred L , Majka Frank A , Barak Anthony J , Stevens J D , Holthaus J M
Published: January 2020

A detailed study of the Akerfeldt test for plasma oxidase activity has been carried out and it has been found that:

1. The optimum activity of the enzyme system involved occurs at pH 5.5-6.0.

2. The amount of plasma needed for the test at pH 6.0 can be reduced to 0.2 ml.

3. The reduced amount of plasma removed the inhibitory influence of albumin and a linear response was always obtained.

4. The inhibitory effect of albumin and glutathione is due in part to inhibiting the enzyme system, and in part to the reduction of oxidized DPP.

5. The inhibiting influence of Versene appears to be due to the chelating and inactivation of heavy metal catalysts.

6. The effect of ascorbic acid is solely one of increasing the lag period without inhibiting the enzyme system.

As a result of this study a modification of the Akerfeldt test is proposed. With this proposed method it was determined that the plasma oxidase activity, ACA, of 77 normal individuals was 8.0 ± 2.8 units. 4101 Woolworth Ave. Omaha 5, Neb.
Electrophoretic Migration Pattern of Serum Glutamic Oxalacetic Transaminase
Authors: Shepherd Herndon G , McDonald Hugh J
Published: January 2020

Using the combined technics of the ionographic separation of serum proteins in a paper-stabilized medium, as described by McDonald et al. (16, 17, 18), and the spectrophotometric procedure for the determination of transaminase activity developed by Karmen (3, 14), the electrophoretic migration pattern of the enzyme glutamic oxalacetic transaminase in rat serum has been examined. The major portion of the transaminase activity has been found to be associated with the α-2 globulin fraction of the serum proteins. Further evidence has been presented for the assumption of a nonionic linkage between the enzyme and its coenzyme, pyridoxal phosphate.
Vitamin B12 Excretion as Index of Hepatic Disorders
Authors: Baker Herman , Brill G , Pasher I , Sabotka Harry
Published: January 2020

Observations on lowered excretion of vitamin B12 after intramuscular injection of 60 µg. of this vitamin in hepatic disease have been extended and confirmed. Except for some borderline cases in other diseases with possible involvement of the liver, we find low excretion in rheumatic heart disease as well as in lobar pneumonia, previously reported. The mechanism underlying the deviations from the normal situation in liver disease and rheumatic heart disease in respect to the vitamin B12 binding factor, to the serum protein composition, and the role played by the kidney is the subject of current studies.