bluuebunny/crossref_metadata_2025_split huggingface dataset:
Measurement of glycosylated hemoglobin on cellulose acetate membranes by mobile affinity electrophoresis.
Authors: Ambler J , Janik B , Walker G 
Published: January 2020

Abstract
In this method for separating glycosylated from nonglycosylated hemoglobin in blood by electrophoresis on cellulose acetate membranes, we exploit the affinity of low-molecular-mass dextran sulfate for the nonglycosylated fraction, which increases the mobility of the latter relative to that of glycosylated hemoglobin. After the membrane strips are cleared and stained, the two fractions are quantified densitometrically. As evaluated by use with blood from diabetics, results compare well with those by chromatography on short columns and by electrophoresis in commercial agar gel films.
Improved Ellman procedure for erythrocyte cholinesterase.
Authors: George P M , Abernethy M H 
Published: January 2020

Abstract
The procedure of Dietz et al. (Clin. Chem. 19: 1309-1313, 1973) for plasma cholinesterase (EC 3.1.1.7) gives a background absorbance of 1.4 A when extended to erythrocyte cholinesterase (EC 3.1.1.8) measurement, because the peak absorbance of the reaction product, 5-thionitrobenzoate, coincides with the hemoglobin Soret band at 410 nm. Consequently, the precision of erythrocyte cholinesterase measurements is poor, and the test is restricted to laboratories with a spectrophotometer having a high signal-to-noise ratio. Use of the detergent benzethonium chloride (Hyamine 1622) instead of quinidine sulfate to stop enzyme action allows readings to be made at 440 nm because the hemoglobin band is shifted to 405 nm and its peak intensity is decreased. Moreover, detergent micelle interactions shift the peak absorbance of the 5-thionitrobenzoate from 410 to 435 nm. Overall, the blank absorbance is decreased to about 0.4 A. This results in an assay that is twice as precise as the previous version and is suited for use in a routine laboratory with a moderate-quality spectrophotometer. Thus erythrocyte cholinesterase measurements can readily be made, to complement plasma cholinesterase in the investigation of exposure to organophosphates.
Direct determination of inorganic phosphorus in serum with a single reagent.
Authors: Muñoz M A , Balón M , Fernandez C 
Published: January 2020

Abstract
Estimation of inorganic phosphate in serum based on the formation of "molybdenum blue" may be simplified by eliminating the reduction stage. The yellow complex formed by the reaction of phosphate with molybdate in an acid medium is measured at 390 nm. The yellow complex behaves in accordance with Beer's law over a wide concentration range (to at least 80 mg of P per liter in the initial sample); its molar absorptivity at 390 nm is 2.51 X 10(3) L mol-1 cm-1. Sensitivity is increased in the presence of a detergent (triethanolamine lauryl sulfate), which is also used to dissolve the proteins. Because only one reagent is used (a stable combination of, per liter, 20 mmol of sodium molybdate, 82 mmol of nitric acid, and 100 mg of the detergent), the method is simple and rapid. We describe a manual procedure and an automated one. Within-run precision was 1.9%, and day-to-day precision less than 7%. Results by the automated method compare favorably (r = 0.96) with those obtained by Drewes's method (Clin Chim Acta 39: 81-88, 1972).
Complexes of immunoglobulins A and G with aspartate aminotransferase isoenzymes in serum.
Authors: Nagamine M , Okochi K 
Published: January 2020

Abstract
We report the presence of complexes between aspartate aminotransferase (AST, EC 2.6.1.1) and immunoglobulin (Ig) in the serum of a patient suffering from lung cancer with metastasis to the liver. After fractionation of the serum by gel filtration, AST-Ig complexes (AST-IgA, AST-IgG) were demonstrated by counterimmunoelectrophoresis. Dissociating the complexes and recombining them with purified isoenzyme fractions, s-AST (cytoplasmic) and m-AST (mitochondrial), revealed that only s-AST binds to IgG, whereas IgA binds to both s-AST and m-AST. Although the association of AST with IgG has been reported, to our knowledge this is the first finding of both AST-IgA and AST-IgG complexes in a patient's serum. Serum AST-IgG complexes have been demonstrated in both healthy and diseased individuals; in the latter category, as reported here and by others, the liver is implicated.
Column deactivation in analysis for underivatized tricyclic antidepressants by gas chromatography with use of a nitrogen detector.
Authors: Vinet B 
Published: January 2020

Abstract
I describe deactivation treatment of the OV-17 chromatographic column to minimize adsorption of tricyclic antidepressant drugs on the solid support of the column. The procedure involves heat treatment at 399 degrees C under a low flow of nitrogen, with bleeding of OV-17 liquid phase from the injector tube into the column. The column is then conditioned with vapors of phenyldiethanolamine succinate, added to the carrier gas stream by bleeding from a coated injector glass tube. This deactivation process much improves the chromatographic performance of the column, allowing a sensitivity at the nanogram level with a nitrogen-sensitive detector. Determinations of tricyclic antidepressants in plasma with such a deactivated column results in a low CV and a linear calibration curve, reflecting the effectiveness of the deactivation.
Effects of contaminants in blood-collection devices on measurements of therapeutic drugs.
Authors: Ji S Q , Evenson M A 
Published: January 2020

Abstract
Substances in evacuated blood-collection devices produce gas-chromatographic peaks with retention times similar to those of drugs. All tubes tested except the serum separator tubes contained tris(2-butoxyethyl) phosphate, as determined by mass spectrometry. In addition, the partition coefficient during the solvent-extraction step increased for some drugs by as much as 40%, while for other drugs it decreased by as much as 30%, depending on the drug and the collection tube. The Becton Dickinson serum separator tube also contains several other compounds identified by mass spectrometry to be dibasic esters used in the preparation of the polyester gel. The Corning serum separator tube and the Venoject serum tube contain still other impurities. The Becton Dickinson royal-blue-stoppered tube contained the least amount of impurities of the tubes tested. CVs of 25 commonly measured drugs in plasma pools increased from 5% for samples collected in glass tubes to greater than 20% for samples collected in evacuated blood-collection tubes. Clearly, accuracy and precision of measurements of therapeutic drugs can be seriously compromised if an inappropriate blood-collection device is used.
Short-term biological variation of plasma analytes in renal disease.
Authors: Fraser C G , Williams P 
Published: January 2020

Abstract
Analytical, intra-individual, and inter-individual components of variation were estimated from duplicate analyses of 11 plasma analytes in an average of 13 specimens obtained, over a two-day period, from nine patients with impaired renal function. Analytical variance was 17.3% of the total variance for sodium; less than 5% of the total variance for potassium, chloride, bicarbonate, albumin, and calcium; and less than 1% for urea, creatinine, glucose, creatine kinase (EC 2.7.3.2), and alanine aminotransferase (EC 2.6.1.2). Average intra-individual variances were of the same order as those found in healthy individuals. All analytes except glucose showed strong individuality. We postulate that, in nonacute pathological processes where new homeostatic steady states are reached, biological variations around the new set points are of the same order as those found in healthy individuals.
Radioimmunometric assay for a monoclonal antibody-defined tumor marker, CA 19-9.
Authors: Del Villano B C , Brennan S , Brock P , Bucher C , Liu V , McClure M , Rake B , Space S , Westrick B , Schoemaker H , Zurawski V R 
Published: January 2020

Abstract
We describe a solid-phase radioimmunometric sandwich assay for a new tumor marker defined by a monoclonal antibody (19-9). This antibody reacts with a carbohydrate antigenic determinant (CA 19-9) found at low concentrations in sera from healthy individuals but frequently increased in sera from patients with adenocarcinomas. The assay is sensitive and simple to perform. It requires duplicate 100-microL samples and may be performed in 6 h. The concentration of CA 19-9 in samples is determined by reference to a standard curve, which is essentially linear from 0 to 120 arbitrary units/mL. The average CV is approximately 10% in the range of 5.8 to 120 units/mL. The minimum detectable dose is 1.4 units/mL and analytical recovery of CA 19-9 is 97.6 to 100.6%. The average concentration of CA 19-9 in sera from 1020 healthy individuals was 8.4 (SD 7.4) units/mL; only 0.6% of such sera had concentrations greater than 37 units/mL. The assay has high specificity (98.5%), even among patients with benign diseases, and has high sensitivity (up to 79%) for patients with gastrointestinal adenocarcinomas, especially those of the pancreas.
Six methods for determining urinary protein compared.
Authors: Dilena B A , Penberthy L A , Fraser C G 
Published: January 2020

Abstract
Inter-laboratory surveys have shown that "routine methods" of urinary protein determination are often unsatisfactory. Therefore, we compared six frequently used methods for determination of protein in urine with respect to linearity, within-batch and between-batch precision, comparative bias, and practicability. We assayed dilutions of human and bovine albumin and serum, and fresh and lyophilized human urine. We find that the AACC Selected Method has poor practicability and poor precision under routine conditions, but good linearity. The sulfosalicylic acid/biuret technique is also impracticable, requires a large sample, and is not linear at low concentrations of urine protein. The Coomassie Brilliant Blue technique has a narrow range of linearity and poor precision. The sulfosalicylic acid/sodium sulfate turbidimetric method is not precise and cannot be standardized with bovine materials. The Ponceau-S technique has good performance characteristics and practicability, and we recommend it for routine laboratory use.
Total bone and liver alkaline phosphatases in plasma: biological variations and reference limits.
Authors: Schiele F , Henny J , Hitz J , Petitclerc C , Gueguen R , Siest G 
Published: January 2020

Abstract
We have studied factors affecting biological variation in total plasma alkaline phosphatase in a population of 32 329 apparently healthy subjects four years old or older. Quantification of the bone and liver isoenzymes after thermal denaturation made it possible to specify the contributions of each isoenzyme to variations in the total activities. The main factors that modify plasma alkaline phosphatase activity are age, sex, hormonal state (puberty or menopause), and morphometric parameters (height, body weight, or degree of overweight). The bone isoenzyme is mainly responsible for the variations associated with age, sex, and puberty and to some extent with the menopause. Activity of the liver isoenzyme was also altered at the menopause and by certain drugs, such as oral contraceptives and blood-lipid-lowering agents. These data allow us to propose reference limits for total plasma, bone, and liver alkaline phosphatases according to age and sex.
An enzymic creatinine assay and a direct ammonia assay in coated thin films.
Authors: Sundberg M W , Becker R W , Esders T W , Figueras J , Goodhue C T 
Published: January 2020

Abstract
We developed a thin-film enzymic assay for creatinine that makes use of creatinine iminohydrolase (EC 3.5.4.21) to convert creatinine to N-methylhydantoin and ammonia. The ammonia diffuses through a semipermeable layer and is quantitated by reaction with bromphenol blue. A paired analysis of the sample on a separate coating without the enzymic reaction measures endogenous ammonia and, for samples with normal concentrations of ammonia, allows accurate determination of serum creatinine to 150 mg/L without dilution. Results of this assay (y) compare well with those by a liquid-chromatographic comparison assay (x) by linear regression (slope = 0.935, intercept = 1.13 mg/L, r2 = 0.995). It is insensitive to many substances, such as ketones and keto acids, that interfere with conventional assays. Results of the ammonia assay (y) correlate well with those by a semi-automated enzymic assay (x) based on glutamate dehydrogenase (slope = 1.068, intercept = 17.3 mumol/L, r2 = 0.985).
Liquid-chromatographic determination of tobramycin in serum with spectrophotometric detection.
Authors: Kabra P M , Bhatnagar P K , Nelson M A , Wall J H , Marton L J 
Published: January 2020

Abstract
We describe a simple, precise, accurate, and specific liquid-chromatographic procedure for determination of tobramycin in 50 microL of serum. Tobramycin and the internal standard (sisomicin) are quantitatively converted into their trinitrophenyl derivatives by reaction with a water-soluble derivatizing agent (2,4,6-trinitrobenzenesulfonic acid) at 70 degrees C for 30 min. The derivatives are extracted from the crude reaction mixture by using a reversed-phase Bond-Elut C18 column, and separated on a reversed-phase octyl column with a mobile phase consisting of an acetonitrile/phosphate buffer (70/30 by vol) at a flow rate of 3.0 mL/min. The eluted compounds are detected at 340 nm, and quantified from their peak areas. Chromatography is complete in less than 4.5 min at the optimum column temperature of 50 degrees C. The lower limit of detection for tobramycin is less than 0.2 mg/L. Analytical recoveries for tobramycin varied from 94 to 99%, linearity extended to 25 mg/L, and day-to-day precision (CV) was between 4.6 and 5.1%. Numerous drugs and antibiotics tested do not interfere. Results correlate well (r greater than 0.95) with those by radioimmunoassay and EMIT.
"Sandwich" enzyme immunoassay for serum ferritin with polypropylene test tubes as the solid phase.
Authors: Revenant M C 
Published: January 2020

Abstract
A "sandwich" enzyme immunoassay for ferritin in human serum is described, in which horseradish peroxidase-labeled antibody and a very sensitive chromogen, 2,2'-azino-di(3-ethyl-benzthiazolin-6-sulfonate), are used. The solid phase is polypropylene test tubes treated with glutaraldehyde; immunologic reactions are developed during constant rotation of the tubes. The assay requires 20 microL of serum per assay and takes less than 3 h. The standard curve is linear between 0 and 400 micrograms of serum ferritin per liter. Analytical recoveries of various amounts of standard added to a serum sample ranged from 92 to 98.6%. The sensitivity is 2 micrograms/L, which translates to 0.4 ng per assay tube. Within-run CV ranges from 1.6 to 5.4% and between-run from 4.2 to 7.8% according to the ferritin concentration. Results by competitive radioimmunoassay correlated well (r = 0.98). No "hook effect" was observed for concentrations up to 13 mg/L. The reference interval is 40-240 micrograms/L for men, 8-100 micrograms/L for women.
Laboratory evaluation of the Boehringer Mannheim "Hitachi 705" automatic analyzer.
Authors: Kineiko R W , Floering D A , Morrissey M 
Published: January 2020

Abstract
We evaluated a new multi-channel chemistry analyzer, the Hitachi 705 Automatic Analyzer, marketed by Boehringer Mannheim Diagnostics, Inc. The instrument is a computer-controlled discrete analyzer, which can be run in a combination profile mode and single-test mode. Sixteen different tests per sample may be performed at the rate of 180 tests per hour. The Hitachi 705 is especially suitable for use in hospitals that do not perform profile testing. Precision and linearity were excellent and the instrument was relatively trouble-free, with little operator attention required during operation. The Hitachi 705 was easily interfaced to our laboratory computer. We compared the performance of the instrument with that of the Du Pont aca; the two instruments compared favorably.
Proportion of glycosylated hemoglobin in erythrocytes of a person with hemoglobins A, S, and G Philadelphia.
Authors: Krauss J S , Jonah M H , Yau S J , Trinh M 
Published: January 2020

Abstract
The apparent proportion of column-chromatographically measured glycosylated hemoglobin in erythrocytes from an individual with hemoglobins A, S, and G was only 2.3% because the slow glycosylated variant hemoglobins were retarded in the column. In contrast, the value for glycosylated hemoglobin was 7.8% by a new cellulose acetate electrophoretic method that includes use of dextran sulfate buffer. The erythrocyte metalloprotein, carbonic anhydrase B, was shown to co-migrate with glycosylated hemoglobin by this technique, however. Thus carbonic anhydrase B, HbF, and HbA all have weak attraction for negative charges at acid pH. We believe that carbonic anhydrase B should contribute significantly (at least 10-20% absorbance) to the HbA1 by this electrophoretic method. We conclude that microcolumn chromatography should remain the method of choice for HbA1 determination, that subject-based reference intervals should be used for HbS or HbC heterozygotes, and that electrophoretic HbA1 methods should be reserved for use with both HbS and HbC homozygotes and HbSC disease.
A reference method for measurement of alkaline phosphatase activity in human serum.
Authors: Tietz N W , Burtis C A , Duncan P , Ervin K , Petitclerc C J , Rinker A D , Shuey D , Zygowicz E R 
Published: January 2020

Abstract
We present an official AACC reference method for the measurement of alkaline phosphatase, the culmination of optimization experiments conducted by a group of independent laboratories. The details of this method and evaluation of factors affecting the measurement are described. A metal ion buffer has been incorporated that maintains optimal and constant concentrations of zinc(II) and magnesium(II) ions. Final reaction conditions are: pH (30 degrees C), 10.40 +/- 0.05; 2-amino-2-methyl-1-propanol buffer, 0.35 mol/L; 4-nitrophenyl phosphate, 16.0 mmol/L; magnesium acetate, 2.0 mmol/L; zinc sulfate, 1.0 mmol/L; and N-(2-hydroxyethyl)ethylenediaminetriacetic acid, 2.0 mmol/L.
Improved dialysis method for free thyroxin in serum compared with five commercial radioimmunoassays in nonthyroidal illness and subjects with abnormal concentrations of thyroxin-binding globulin.
Authors: Helenius T , Liewendahl K 
Published: January 2020

Abstract
We describe a method for free thyroxin (FT4) in serum, based on radioimmunoassay of T4 in serum dialysate, FT4(D). The method is analytically accurate, sensitive, reproducible, and suitable for routine use in the clinical laboratory. We compared results by this method with those obtained with five commercial FT4 assays (Amerlex, GammaCoat, ImmoPhase, LiquiSol, Spiria) and the free T4 index (FT4I). In several of the patients with nonthyroidal illness FT4(D) was above normal and FT4 as measured with the commercial assays was subnormal. In the third trimester of pregnancy all the FT4 methods gave decreased mean values, though the decreases were of various magnitudes: FT4(D) 32%, Amerlex 44%, GammaCoat 40%, Spiria 19%, LiquiSol 16%, and ImmoPhase 13%, respectively. FT4I was significantly higher than normal during late pregnancy. In women taking oral contraceptives the mean FT4I was increased, but there was no significant effect on the results obtained with the various FT4 methods. All subjects with hereditarily high or low serum thyroxin-binding globulin had normal FT4(D) and abnormal FT4I. Amerlex, ImmoPhase, and LiquiSol misclassified some of the subjects with hereditarily abnormal thyroxin-binding globulin.
Capillary gas-chromatographic determination of urinary homovanillic acid and vanillylmandelic acid.
Authors: Tuchman M , Crippin P J , Krivit W 
Published: January 2020

Abstract
This relatively simple, rapid method for quantification of homovanillic acid (HVA) and vanillylmandelic acid (VMA) involves solvent extraction and capillary gas chromatography. With use of this extraction method, the overall analytical recovery from an aqueous solution is 92.5% for HVA and 79.2% for VMA. 3,4-Dihydroxybenzoic acid is the internal standard. Minimal detectable quantities with this method are less than 1 mg/g of creatinine. Capillary gas chromatography produces a chromatogram that is superior to that of packed-column gas chromatography. We also report quantitative results for urinary HVA and VMA in neuroblastoma patients and in normal individuals, demonstrating the diagnostic value of this method.
Radioimmunoassay for human prothrombin.
Authors: Krishnan G 
Published: January 2020

Abstract
I describe a radioimmunoassay for human prothrombin, with use of a double-antibody technique. Antiserum raised in rabbits was absorbed with Al(OH)3 and heated to 56 degrees C for 30 min. 125I-labeled prothrombin retaining more than 90% of its biological activity was prepared by the iodine monochloride method. The mean concentration of prothrombin in plasma of 12 normal individuals was 100 +/- 29.4 mg/L (2 SD). Prothrombin values were somewhat lower than those obtained by the Laurell electroimmunoassay or by two-stage biological assay of the same plasma, done the same day. The biological values were converted to protein on the basis of 1960 int. units/mg by comparison with the other two assays. The ability of activation fragments of human prothrombin to inhibit binding of labeled prothrombin to its antibody was evaluated by competitive radioimmunoassay. Although precipitin lines formed with undiluted antiserum against all the fragments tested (F-1, F-1.2, prethrombin-1, and thrombin), none of the fragments competed well with prothrombin, even in 10-fold molar excess. Evidently, the structural integrity of the prothrombin molecule is essential for its maximum binding to the antiserum, and antigenic sites are lost during its activation.
Micromethod for determining plasma ammonia nitrogen with use of an ion-selective electrode.
Authors: Cooke R J , Jensen R L 
Published: January 2020

Abstract
A micromethod for measuring the ammonia nitrogen content of plasma by use of an ion-selective electrode is evaluated and described. The effect of storing plasma for 24, 48, and 72 h at -70 degrees C was evaluated. Values for newborns and fasting adults were 880 micrograms/L (SD, 210 micrograms/L) and 620 micrograms/L (SD, 170 micrograms/L), respectively.
Reversal of changes in lipoprotein A and lipoprotein B cholesterol during and for a year after a detoxication treatment program in chronic alcoholism.
Authors: Perier C , Janin J , Pierre-Louis S , Frey J 
Published: January 2020

Abstract
We studied the individual and occasional changes in lipid metabolism induced by chronic alcohol abuse. In addition, the influence of a detoxication treatment program on the evolutionary changes in some serum lipidic components was studied for a one-year period. Before this program, total cholesterol was above normal, with high values for LP-A cholesterol, whereas for some patients LP-B cholesterol was increased. After the program, there was an increase in total cholesterol, LP-B cholesterol, and apolipoprotein B, with a decrease in LP-A cholesterol. These evolutionary changes continued during the one-year period after the end of the inpatient program.
Determination of urinary vanillylmandelic acid by liquid chromatography with electrochemical detection.
Authors: Moleman P , Borstrok J J 
Published: January 2020

Abstract
We describe an improved method for the assay of urinary vanillylmandelic acid by "high-performance" liquid chromatography, with electrochemical detection. A 1-mL aliquot of urine is acidified and extracted with ethyl acetate, then the ethyl acetate extract is extracted with phosphate buffer, pH 8.5. An acidified aliquot of the phosphate extract is injected into a reversed-phase column and vanillylmandelic acid is detected electrochemically. The between-day CV is 5-6% for concentrations ranging from 10 to 75 mumol/L. We also discuss the critical steps for extraction and calibration.