bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improved determination of transketolase activity in erythrocytes.
Authors: Takeuchi T , Nishino K , Itokawa Y 
Published: January 2020

Abstract
We describe a new and better method for determining transketolase (EC 2.2.1.1) activity in human erythrocytes. Heating the hemolysate (55 degrees C, 5 min) inactivates transaldolase (EC 2.2.1.2), the enzyme that catalyzes the formation of fructose 6-phosphate and erythrose 4-phosphate from sedoheptulose 7-phosphate and glyceraldehyde 3-phosphate. The net effect is that the quantity of sedoheptulose 7-phosphate formed more precisely represents the transketolase activity, which is unaffected under these conditions. Use of ribosephosphate isomerase (EC 5.3.1.6) and ribulose-phosphate 3-epimerase (EC 5.1.3.1) to establish an equilibrium among the pentoses allowed us to confirm the stoichiometry of the transketolase reaction. We also discuss the effect of thiamin pyrophosphate, which is used to reflect thiamin deficiency.
Are reference limits for serum creatine kinase valid in detection of the carrier state for Duchenne muscular dystrophy?
Authors: Gruemer H D , Miller W G , Chinchilli V M , Leshner R T , Hassler C R , Blasco P A , Nance W E , Goldsmith B M 
Published: January 2020

Abstract
We evaluated serum creatine kinase (CK) as an index to heterozygosity in Duchenne muscular dystrophy. When the 97.5th percentile of the CK normal reference interval was selected as the cutoff point, only 31% of 28 obligate carrier mothers and 24% of 43 mothers of simplex cases (those with only one occurrence of dystrophy in the kindred) exceeded this cutoff value. The outcome depended to some degree on the method used for establishing the reference limit for 379 presumably non-carrier, ambulatory women. The considerable overlap of CK activities between the control and carrier population as well as the non-gaussian distribution of the data permitted no satisfactory approach for differentiating these two populations. Neither the application of likelihood ratios, which evaluates a continuum of results without the dichotomy of a cutoff point, nor the application of predictive value based on sensitivity and specificity, which involves use of a cutoff value for decision making, provided a reliable estimate of carrier status. There was no significant difference (2 alpha = .19) between the median CK activity of obligate carrier mothers and mothers of simplex cases. The serum CK test does not provide data that either support or reject the Haldane hypothesis.
Silver staining of unconcentrated cerebrospinal fluid in agarose gel (Panagel) electrophoresis.
Authors: Mehta P D , Mehta S P , Patrick B A 
Published: January 2020

Abstract
We subjected cerebrospinal fluid (CSF) from 20 patients with multiple sclerosis and 20 patients with other neurological diseases to agarose gel ( Panagel ) electrophoresis followed by staining with silver. Ten microliters of unconcentrated CSF from multiple sclerosis patients containing 0.4 to 0.8 microgram of immunoglobulin G was found to be optimum for detection of oligoclonal IgG bands, so identified by immunofixation. The band patterns for unconcentrated CSF stained with silver were almost identical to those for the same CSF concentrated 40-fold and stained with Coomassie Brilliant Blue. Silver staining thus enables the clinical laboratory to electrophorese unconcentrated CSF on commercially prepared ( Panagel ) plates.
Improved assay of unconjugated estriol in maternal serum or plasma by adsorption and liquid chromatography with fluorimetric detection.
Authors: Andreolini F , Borra C , Di Corcia A , Laganà A , Samperi R , Raponi G 
Published: January 2020

Abstract
In this improved assay only a 500-microL sample is needed and a single assay can be done within 30 min, 10 samples within 90 minutes. The sample of serum or plasma is diluted 20-fold with water, and the estriol is adsorbed from it onto graphitized carbon black ( Carbopack B, Supelco ). After two washings the estriol is desorbed with chloroform/methanol (60/40 by vol), which then is evaporated. The residue is redissolved in 50 microL of water/acetonitrile, and 20 microL is injected into the chromatograph. Analytical recovery for estriol-supplemented serum or plasma averaged 98.6%. Day-to-day CVs ranged from 3.9% at 2 micrograms/L to 2.1% at 20 micrograms/L. The limit of sensitivity is 0.3 micrograms/L, which makes this procedure suitable for determination of estriol even in the first half of pregnancy. Our method is inexpensive, and shows that liquid chromatography can be used to determine estriol in pregnancy serum or plasma. It also is more sensitive and precise and requires less sample than other such methods.
Electrothermal atomic absorption determination of aluminum in tissues dissolved in tetramethyl ammonium hydroxide.
Authors: Stevens B J 
Published: January 2020

Abstract
In this rapid, precise method for the accurate determination of aluminum in biological tissue, the only preparative step required is the dissolution of the sample in hot aqueous tetramethyl ammonium hydroxide, followed by dilution with ethanol. Aluminum is measured by electrothermal (graphite furnace) atomic absorption spectroscopy, with direct reference to aqueous standards. The CVs for the method within-day and day-to-day are 3.0% and 6.8%, respectively. Analytical recovery of added aluminum is 86 to 108%, and matrix effects are minimal. Measurement of aluminum in tissue from normal laboratory rats and rats injected with aluminum gave values close to those found by an acid digestion method, but higher than those obtained by extraction with a saturated solution of ethylenediaminetetraacetate.
Discrepancies between serum free triiodothyronine and free thyroxin as measured by equilibrium dialysis and analog radioimmunoassay in nonthyroidal illnesses.
Authors: Liewendahl K , Tikanoja S , Helenius T , Välimäki M 
Published: January 2020

Abstract
We determined free triiodothyronine (FT3) and free thyroxin (FT4) in serum of patients with various nonthyroidal illnesses (NTI), by both commercial analog-type radioimmunoassays (A) and new equilibrium dialysis procedures (D). The mean FT3 was significantly lower in NTI by both techniques, but the decreases were of different magnitudes. The FT3(D):FT3(A) ratio was 1.96, vs 1.11 for healthy controls. In NTI the mean FT4(D) was somewhat increased, whereas the mean FT4(A) was much lower than normal, the above ratio being 1.70, vs 0.92 for controls. We ascribe these discrepancies, at least in part, to binding of radiolabeled T3- and T4-analog tracers to serum albumin.
Ultrastructural localization of aluminum in patients with dialysis-associated osteomalacia.
Authors: Verbueken A H , Van de Vyver F L , Van Grieken R E , Paulus G J , Visser W J , D'Haese P , De Broe M E 
Published: January 2020

Abstract
Using laser microprobe mass analysis, we studied the ultrastructural localization of aluminum in liver and bone tissue of chronic-hemodialysis patients with proven aluminum-induced osteomalacia. In the liver, aluminum was observed to be almost exclusively associated with iron. Detectable aluminum and large amounts of iron were found in lysosomes of both hepatocytes and Kupffer cells. In bone, aluminum was localized at the osteoid/calcified-bone interface and also was associated with iron in some cases.
Electrophoretic variants of alanine aminopeptidase, alkaline phosphatase, and gamma-glutamyltransferase in urine.
Authors: Jung K , Wischke U W 
Published: January 2020

Abstract
The three brush-border enzymes--alanine aminopeptidase (EC 3.4.11.2), alkaline phosphatase (EC 3.1.3.1), and gamma-glutamyltransferase (EC 2.3.2.2)--are present in the urine of healthy persons in two variants, a particulate form and a soluble one. They can be separated by electrophoresis in agarose gel and by ultracentrifugation. The particulate forms exhibit similar electrophoretic mobility, but the soluble forms of these brush-border enzymes differ in their electrophoretic mobilities. The enzyme components of the particulate activity can be mobilized by Triton X-100 and trypsin. The electrophoretic mobility of the soluble forms of alanine aminopeptidase and gamma-glutamyltransferase is slowed by neuraminidase treatment. Both forms of gamma-glutamyltransferase are influenced in their electrophoretic mobility by treatment with n-butanol/diisopropyl ether, showing their lipid dependence. These findings enhance our knowledge of the biochemical nature of brush-border enzymes in urine.
Direct potentiometric determination of sodium ion in blood. II. Influence of cations.
Authors: Bijster P , Vink K L 
Published: January 2020

Abstract
We measured the emf of NaCl solutions (120-160 mmol/L), with and without the addition of KCl (5-20 mmol/L), CaCl2 (2-8 mmol/L), or MgCl2 (1-4 mmol/L). Measurements were made with a home-built cell in steady-state and with two commercial direct potentiometric analyzers about 20 s after the sample was introduced. We calculated the sodium ion activity in the mixed NaCl-KCl solutions according to different thermodynamic theories and found almost the same results. We conclude that the influence on the emf of physiological concentrations of these cations was negligible when emf measurements were made in steady-state with the home-built cell. Of the three added cations, K+ caused the greatest increase in apparent sodium ion activity (up to about 4%) when emf measurements were made with commercial analyzers, owing to low salt-bridge concentration and the short measuring time of about 20 s.
Two-site monoclonal antibody assays for human heart- and brain-type creatine kinase.
Authors: Jackson A P , Siddle K , Thompson R J 
Published: January 2020

Abstract
Monoclonal antibodies have been raised against human heart- and brain-type creatine kinase (CK-MB and CK-BB). We used a low-affinity monoclonal antibody to develop a simple two-step immunoaffinity purification procedure for native CK-MB. Antibodies of higher affinity were used to construct specific two-site immunoradiometric assays for CK-MB and CK-BB. In the assay for CK-MB we used an 125I-labeled B subunit-specific antibody with an immobilized anti-M subunit antibody--adding either simultaneously, for a 1-h assay in which between 5 and 1000 ng of CK-MB per milliliter could be measured with an intra-assay CV of 4% to 20%, or sequentially, for a 2-h magnetic separation assay in which between 0.5 and 1000 ng/mL could be measured with an intra-assay CV of 14 to 19%. In both versions CK-BB up to 100 ng/mL and CK-MM up to 5000 ng/mL did not interfere. In the assay for CK-BB we used an 125I-labeled, reduced, and alkylated monoclonal antibody specific for the B subunit of CK-BB, and removed bound isoenzyme with a second immobilized monoclonal antibody specific for a different epitope on the B subunit. Total incubation time for this assay was 5 h. Intra-assay CV was 7.5 to 20% between 0.1 and 1000 ng/mL. CK-MB up to 1000 ng/mL and CK-MM up to 100 000 ng/mL did not interfere. Inter-assay CVs in all three assays varied from 9 to 21%.
Ligand displacement immunoassay: a novel enzyme immunoassay demonstrated for measuring theophylline in serum.
Authors: Hinds J A , Pincombe C F , Kanowski R K , Day S A , Sanderson J C , Duffy P 
Published: January 2020

Abstract
We describe a ligand displacement immunoassay for measurement of theophylline in serum or plasma and show it to be clinically useful. A conjugate of theophylline-specific antiserum covalently bound to micro-crystalline cellulose and a beta-galactosidase-labeled theophylline derivative is prepared as a lyophilized reagent. Sample is added to the conjugate and, after 5-min incubation at room temperature, the bound and displaced enzyme-ligand are separated by brief centrifugation. The enzyme activity of the displaced enzyme-ligand is measured on a spectrophotometer or centrifugal analyzer. Linear calibration curves are obtained with appropriate sample dilution, allowing generation of the standard curve with a saline zero reference and a single calibrator. Performance of the assay compares favorably with that of other theophylline assays; comparison studies with use of 145 clinical specimens gave a coefficient of correlation with EMIT of 0.97.
Two new methods for separating and quantifying bone and liver alkaline phosphatase isoenzymes in plasma.
Authors: Rosalki S B , Foo A Y 
Published: January 2020

Abstract
We describe two new methods for the separation and quantification of the bone and liver isoenzymes of alkaline phosphatase (EC 3.1.3.1) in plasma. In the first, we use wheat-germ lectin to precipitate the bone isoenzyme. About 80% of this, but minimal liver isoenzyme, is precipitated. The activity of the bone isoenzyme is calculated from measuring the alkaline phosphatase activity in the precipitate, that of liver alkaline phosphatase by subtracting the activity of the bone isoenzyme from total alkaline phosphatase activity. The liver fraction will also contain biliary, intestinal, and placental alkaline phosphatase if these are present in the original plasma, but correction for such activity is readily made. In the second method, samples are separated on cellulose acetate membranes that, before electrophoresis, have been soaked in buffer containing wheat-germ lectin. The bone isoenzyme is retarded and clearly separated from the liver fraction, allowing these isoenzymes to be quantified by densitometry. Both methods are rapid, reproducible, and suitable for use in the diagnostic laboratory.
Specific estimation of 24,25-dihydroxyvitamin D in plasma by gas chromatography-mass spectrometry.
Authors: Coldwell R D , Trafford D J , Makin H L , Varley M J , Kirk D N 
Published: January 2020

Abstract
This paper describes a specific mass-fragmentographic method, involving a stable-isotope-labeled internal standard, for measurement of 24,25-dihydroxyvitamin D in human plasma. Vitamin D metabolites were rapidly extracted from plasma by using Sep-Pak C18 cartridges and separated into fractions on Sep-Pak SIL cartridges. The polar fraction, containing the dihydroxylated metabolites, was further purified by "high-performance" liquid chromatography on Zorbax SIL. The fraction containing 24,25-dihydroxyvitamin D was collected, evaporated, and converted to the 24:25-cyclic n-butyl boronate-3-trimethylsilyl ether derivative before analysis by gas chromatography-mass spectrometry. The intensity of the mass fragment (m/z 449, m/z 455 for the hexadeuterated internal standard) arising from the loss of one of the angular methyls and the 3-silanol group [( M-90-15]+) was monitored. The minimum limit of detection for this method is about 0.1 microgram/L. Inter- and intra-assay reproducibility was acceptable, and analytical recovery of added 24,25-dihydroxyvitamin D3 over the concentration range 1.0 to 5.0 micrograms/L was quantitative. Concentrations of 24,25-dihydroxyvitamin D3 in plasma of 21 apparently healthy volunteers were between 0.55 and 5.39 micrograms/L, higher values being obtained after prolonged exposure to the sun. No 24,25-dihydroxyvitamin D2 could be detected in any plasma sample examined.
Electrothermal atomic absorption spectrometric determination of aluminum in serum with a new technique for protein precipitation.
Authors: Brown S , Bertholf R L , Wills M R , Savory J 
Published: January 2020

Abstract
We have studied the electrothermal atomic absorption measurement of aluminum in serum samples by direct analysis with standard additions and the use of a matrix modifier. We have also measured aluminum by analysis of the supernate after pretreatment of serum with concentrated nitric acid to precipitate proteins, and have compared the results obtained by these two techniques. Both appear to eliminate interferences arising from the serum matrix. We quantified the aluminum by utilizing a stabilized temperature (L'vov) platform. Within-run precision (CV) for the standard-additions method was 16.6% (means = 6.5 micrograms/L) and 6.0% (means = 86.8 micrograms/L) and for the protein precipitation method was 10.1% (means = 10.9 micrograms/L) and 4.2% (means = 88.5 micrograms/L). Linearity of the standard curve extended from 0 to 120 micrograms/L for the standard-additions method and from 0 to 100 micrograms/L for the protein precipitation method. Samples from 38 patients were analyzed by both techniques, and linear regression analysis yielded the equation y (protein precipitation) = 1.02 X (standard additions) + 2.04.
Automated measurement of amylase isoenzymes with 4-nitrophenyl-maltoheptaoside as substrate and use of a selective amylase inhibitor.
Authors: Okabe H , Uji Y , Netsu K , Noma A 
Published: January 2020

Abstract
We automated a kinetic procedure for determining amylase isoenzymes in serum and urine samples. We used 4-nitro-phenylmaltoheptaoside as substrate and a selective amylase inhibitor with the Abbott-VP bichromatic system. By use of the maximum differences between pancreatic (P) and salivary (S) amylase activities remaining after inhibition by the selective inhibitor and by use of the linear range, a one-point standard method for calibration is proposed for determining amylase activities between about 50 and 1500 U/L when the P/S ratio exceeds 0.2. Results correlated well with those by electrophoresis and the Phadebas method (r = 0.99 for both pancreatic and salivary amylase). Reproducibilities (CVs) were 1.5% to 5.5% for pancreatic amylase and 1.4% to 3.3% for salivary amylase in serum, 0.8% to 2.0% for pancreatic amylase and 0.8% to 2.3% for salivary amylase in urine.
Improved liquid-chromatographic determination of haloperidol in plasma.
Authors: Dhar A K , Kutt H 
Published: January 2020

Abstract
This method for determination of haloperidol in plasma is based on "high-performance" isocratic liquid chromatography with the use of a C8 bonded reversed-phase column at room temperature. Haloperidol and the internal standard (chloro-substituted analog) are extracted from alkalinized plasma into isoamyl alcohol/heptane (1.5/98.5 by vol) and back-extracted into dilute H2SO4. The aqueous phase is directly injected onto the column. The mobile phase is a 30/45/25 (by vol) mixture of phosphate buffer (16.5 mmol/L, pH 7.0), acetonitrile, and methanol. Unlike other liquid-chromatographic procedures for haloperidol, commonly used psychotropic drugs do not interfere. Analysis can be completed within an hour. The procedure is extremely sensitive (1.0 microgram/L) and is well reproducible (CV 5.6% for a 2.5 micrograms/L concentration in plasma).
Improved detection of oligoclonal IgG in cerebrospinal fluid by isoelectric focusing in agarose, double-antibody peroxidase labeling, and avidin-biotin amplification.
Authors: Olsson T , Kostulas V , Link H 
Published: January 2020

Abstract
To demonstrate oligoclonal IgG bands (I) in unconcentrated cerebrospinal fluid, we used isoelectric focusing in agarose followed by protein transfer to cellulose nitrate membrane, double-antibody peroxidase labeling, and avidin-biotin amplification. I can be reliably seen after isoelectric focusing of 5-microL specimens containing 125 ng of IgG (25 mg/L). Thus the technique is more sensitive than others (e.g., silver staining) and more reliable than radioimmunofixation. When we used this technique with fluids from 62 patients with multiple sclerosis and infectious disease of the central nervous system, 84% displayed I, a percentage not increased when the same specimens were concentrated to 3.5 g of IgG per liter, examined by agarose isoelectric focusing, and stained with Coomassie Blue. Results for 53 patients with tension headache and psychoneurosis were all negative. By obviating the need to concentrate samples of cerebrospinal fluid the present method is a useful, sensitive alternative for demonstrating I.
Carboxyhemoglobin and oxygen affinity of human blood.
Authors: Rovida E , Niggeler M , Carlone S , Samaja M 
Published: January 2020

Abstract
We determined normal human blood p50 at various pH values (range 7.0 to 7.6) as a function of the proportion of carboxyhemoglobin (COHb) in total hemoglobin, from 0 to 23%. The d(log p50)/d[COHb] coefficient is 0.00848, independent of pH and 2,3-diphosphoglycerate. The derived equation allows the calculation of p50 as a function of COHb with an approximation of +/- 0.54 mmHg (about 72 Pa), and can be combined with other calculations (Clin Chem 27:1856-1861, 1981; Clin Chem 29:110-114, 1983) to predict p50 under any condition of pH within the range 7.0-7.6, ratio of [2,3-diphosphoglycerate] to [total hemoglobin] (range 0.3-2.5), pCO2 (range 20-90 mmHg), temperature (range 19-43 degrees C), and COHb (range 0-23%).
Raising monospecific antibodies by use of protein components prestained with Remazol Brilliant Blue and separated by disc electrophoresis on polyacrylamide gel.
Authors: Saoji A M , Jad C Y , Yemul V L , Khare P M , Kelkar S S 
Published: January 2020

Abstract
We have reported (Clin Chem 29: 42-44, 1983) that prestaining with Remazol Brilliant Blue permits direct visualization of serum components on disc electrophoresis, and apparently purifies the proteins well. Here we have cut out the bands corresponding to the prestained albumin and transferrin after disc electrophoresis of normal human serum proteins, eluted some individual proteins into saline, and assessed their purity by immunoelectrophoresis and two-dimensional crossed immunoelectrophoresis against polyvalent antihuman serum. These two techniques indicated purity of these antigens. We inoculated rabbits with the eluates containing the pure antigens, and tested the resulting antibodies for monospecificity by immunoelectrophoresis, rocket electrophoresis, and single radial immunodiffusion. From the results we conclude that the antibodies raised against each component were monospecific, and that this is a simple, economical, rapid, and reliable method for obtaining a pure fraction of serum protein for use as an antigen.
Assessment of protein-calorie malnutrition.
Authors: Haider M , Haider S Q 
Published: January 2020

Abstract
We critically review the various methods for assessing protein--calorie malnutrition. These tests are lacking in sensitivity and specificity, and currently no single one can be used as a reliable indicator of malnutrition. However, a combination of several of them can be used as prognostic indicators and are of help in selecting patients who may benefit from nutritional support. Body-composition analyses and functional tests hold the promise of greater applicability in the future. Newer and more nearly accurate tests for use in diagnosis of protein-calorie malnutrition as well as for objectively monitoring short-term changes in response to nutritional repletion are badly needed. Despite a lack of consensus on the desirability of objective nutritional assessment, we expect the use of these procedures in hospitals to increase.
Associations between serum gamma-glutamyltransferase and apolipoproteins: relationships with hepatobiliary diseases.
Authors: Artur Y , Wellman-Bednawska M , Jacquier A , Siest G 
Published: January 2020

Abstract
We studied the association between gamma-glutamyltransferase (GGT) and apolipoproteins A or B in serum of 42 patients with various hepatobiliary diseases. Binding of the enzyme to apolipoprotein A is not related to a clearly defined disease, but appears to be mainly influenced by the ratio of total cholesterol to GGT activity. An important fraction of GGT activity is associated with apolipoprotein B in patients with icteric or anicteric cholestasis. Conversely, in noncholestatic patients, the percentage of apolipoprotein B-bound GGT activity is low. Addition of the "heavy" form of GGT, obtained by solubilizing the membrane-bound enzyme with detergents, to a serum with low GGT activity led to the binding of the enzyme only to apolipoprotein A. The "light" form of GGT, obtained by limited proteolysis of the "heavy" form and added to the same serum, did not bind to either apolipoprotein A or apolipoprotein B. Thus, the association between the serum enzyme and apolipoprotein A apparently results from nonspecific aggregation of the amphiphilic "heavy" form of the enzyme. The origin of the apolipoprotein B-GGT complexes found in cholestatic patients needs further investigation.