bluuebunny/crossref_metadata_2025_split huggingface dataset:
Two-dimensional electrophoretic analysis of muscle contractile proteins in patients with idiopathic scoliosis.
Authors: Whalen R G , Ecob M S 
Published: January 2020

Abstract
Muscle biopsies from patients with idiopathic scoliosis were analyzed by two-dimensional gel electrophoresis. Both isoelectric focusing and nonequilibrium pH-gradient electrophoresis were used in the first dimension of the separations, to obtain maximum information from each biopsy specimen. The identification of the various contractile proteins and their isoforms was considered, based in part by analogy with studies on animal models. The myosin light chains and the TN-C subunit of troponin were the most useful qualitative markers indicative of the muscle phenotype. Convex and concave paraspinal muscles were analyzed from 13 patients with idiopathic scoliosis. Eight of the patients had light chain and TN-C subunits characteristic of both fast and slow contracting muscle. However, five patients had mixtures of fast and slow proteins only in the concave muscle, the convex muscle being composed exclusively of slow light chains and slow TN-C. Possible mechanisms leading to such a situation and the implications of these results concerning the muscle pathology are discussed.
Lymphocyte, monocyte, and granulocyte proteins compared by use of two-dimensional electrophoresis.
Authors: Gemmell M A , Anderson N L 
Published: January 2020

Abstract
We compared cellular proteins from normal human blood lymphocytes, monocytes and granulocytes, using high-resolution two-dimensional electrophoresis. The leukocytes were isolated from peripheral blood by centrifugation on density step gradients (yielding a fraction of purified granulocytes and a lymphocyte/monocyte mixture) and monocytes were subsequently separated from lymphocytes by virtue of their adherence to plastic. Wright-stained smears indicated that each of the three resulting fractions was 90 to 95% pure. The cells were labeled with [35S]methionine after various intervals in culture, then solubilized and analyzed by two-dimensional electrophoresis. Although most proteins in each cell type are common to all three, there are nevertheless several specific marker proteins that distinguish one cell type from another. We also examined the appearance of these markers in three lines of cultured cells from humans (GM607, a B-lymphoblastoid line; HL-60, a promyelocytic leukemic line; and 1494, a normal skin fibroblast).
Interference by ascorbic acid in test systems involving peroxidase. I. Reversible indicators and the effects of copper, iron, and mercury.
Authors: White-Stevens R H 
Published: January 2020

Abstract
I describe the mechanism whereby ascorbic acid can hamper test systems involving a peroxide-generating system, peroxidase, and a benzidine-type indicator. In test media such as urines, abnormally high concentrations of ascorbic acid may give rise to false negatives in the determination of analytes such as glucose. Absorbance measurements in solution or reflectance measurements on commercially available paper reagent strips demonstrate either inhibition of visible activity by ascorbic acid or a lag time in the development of oxidized indicator color. The duration of the lag time is proportional to the ascorbic acid concentration, is inversely proportional to the enzyme concentration, and is also affected by concentrations of hydrogen peroxide and o-tolidine indicator. The same results were seen in both citrate buffer pH 5 and phosphate buffer pH 7. Because the complete system (o-tolidine indicator, hydrogen peroxide, and peroxidase) must be present if the ascorbate is to be oxidized rapidly, this indicates that ascorbic acid inhibits color development by re-reducing oxidized indicator as fast as it is formed; the o-tolidine then acts catalytically in oxidizing ascorbic acid. Added Cu2+ and Fe3+, both known to react with ascorbic acid, had measurable but small effects on the system. In contrast, Hg2+ abolished the ascorbic acid-elicited lag time, even when present in near-stoichiometric concentration. Hg2+ showed little inhibitory effect on the activity of either glucose oxidase or peroxidase. Presumably it rapidly oxidizes ascorbic acid to dehydroascorbate. The reaction of mercuric ion with ascorbate was measured by reflectance measurements of paper reagent strips in addition to absorbance measurements of solution assays; equivalent results were obtained. Incorporation of Hg2+ into reagent strips can thus render both strips and solution diagnostic tests insensitive to interfering substances such as ascorbic acid.
Interference by ascorbic acid in test systems involving peroxidase. II. Redox-coupled indicator systems.
Authors: White-Stevens R H , Stover L R 
Published: January 2020

Abstract
Ascorbic acid hampers some test systems based on use of peroxidase (EC 1.11.1.7) and redox indicators, by producing a lag time in color development. With reversible indicators, no color development occurs during the ascorbic acid lag time. With oxidatively coupled indicator systems, such as 3-methyl-2-benzothiazolinone hydrazone (MBTH) and a suitable coupler such as chromotropic acid (CTA; 4,5-dihydroxynaphthalene-2,7-disulfonic acid), ascorbic acid diminishes the rate of color development, but does not abolish it. The effect of ascorbic acid strongly depends on the reaction pH as well as the nature of the coupler used. The ascorbate-elicited reduction (or lag) in color development was inversely proportional to the concentrations of MBTH and virtually unaffected by changes in CTA coupler concentration. The rate of color development following the lag was directly proportional to the concentration of MBTH but unaffected by the CTA. These observations suggest that peroxidase with H2O2 catalyzes the oxidation and activation of MBTH to an oxidized species (MBTHox). This species is reduced by ascorbic acid and at the same time couples oxidatively with CTA. Thus, the activity during the ascorbate-induced lag time reflects this competition of ascorbic acid and coupler for MBTHox. This study of peroxidase/ascorbate lag time with the redox coupled indicator system has led to the selection of fast couplers that are highly resistant to interference by ascorbic acid. Suitable resistant couplers (e.g., chromotropic acid, Chicago acid, and H acid) appear to be aromatic ring systems with highly activating substituents and directing toward electrophilic aromatic substitution at the ortho and para positions.
Monitoring octanoic and decanoic acids in plasma from children with intractable epilepsy treated with medium-chain triglyceride diet.
Authors: Haidukewych D , Forsythe W I , Sills M 
Published: January 2020

Abstract
We describe a procedure for gas-chromatographic determination of n-octanoic and n-decanoic acids in 100 microL of plasma from children with intractable epilepsy treated with medium-chain triglyceride (MCT) diet. With n-nonanoic acid as the internal standard, the extraction efficiencies for octanoic and decanoic acids were 98 and 105%, respectively. Within-run CVs for octanoic acid at 0.5, 1.0, 2.5, 5.0, 7.5, and 10.0 micrograms/0.1 mL were 8.8, 7.9, 8.5, 6.5, 4.3, and 5.7%, respectively. For decanoic acid at identical concentrations, the CVs were 10.0, 7.4, 4.9, 4.0, 2.6, and 3.5%, respectively. For 10 children on MCT diet (45.9% of calories supplied as MCT) the mean concentrations of octanoic and decanoic acids were 44.2 and 27.0 mg/L, respectively. Presence of relatively "high" quantities of these acids in plasma may contribute to seizure control when MCT diet is prescribed for intractable childhood epilepsy.
Computer analysis of two-dimensional gels: semi-automatic matching.
Authors: Miller M J , Vo P K , Nielsen C , Geiduschek E P , Xuong N H 
Published: January 2020

Abstract
We describe a computer program system for finding, quantitating, and matching the protein spots resolved on a two-dimensional electropherogram. The programs that locate and quantitate the incorporation of radioactivity into individual spots are totally automatic, as are the programs for matching protein spots between two exposures of the same gel. A semi-automatic method is used to match protein spots between different gels. This procedure is quite fast with the use of a computer-graphic display, which is also helpful in the editing process. A data base is set up and programs have been written to correlate matched protein spots from multi-gel experiments and to efficiently plot out quantitative data from sequences of equivalent spots from many gels or even many multi-gel experiments. The practical use of this system is discussed.
Two-dimensional gel electrophoresis of serum specimens from a normal population.
Authors: Tracy R P , Currie R M , Young D S 
Published: January 2020

Abstract
We examined sera from a normal population by two-dimensional gel electrophoresis, to establish the normal pattern of serum proteins and to investigate genetic polymorphisms. With such information in hand, specimens from patients with certain diseases may be readily evaluated. Towards this goal, we optimized the ISO-DALT system (Proc. Natl, Acad, Sci, USA 74: 5421--5425, 1977) for routine phenotyping of alpha 1-antitrypsin, haptoglobin, GC-globulin, alpha 2-HS-glycoprotein, and transferrin, as well as a previously unknown polymorphic protein. We examined the effects of aging the specimens for 2 h at room temperature (no changes) or at -20 degrees C for several months (small changes), as well as serum/plasma differences and the effect of protease inhibitors. Silver-stain methods were modified to allow simultaneous staining of 10 gels, with reasonably good reproducibility of stain intensity. We quantitated silver-stained gels by densitometry of photographic transparencies. Very small samples suffice with this stain (0.5 microL of serum or plasma), allowing the use of "finger-stick" methods instead of venipuncture, yet the patterns are better resolved and easier to read than those for 10-microL specimens processed on gels stained with Coomassie Blue. Our techniques for rapidly removing albumin and IgG allow the investigator to examine areas on the gel that ordinarily are obscured. The region of haptoglobin has been examined by using serum from an ahaptoglobinemic donor. Finally, we present an expanded "normal" map illustrating the composite protein pattern.
Reproducibility and quality assurance of two-dimensional gel electrophoresis of serum specimens.
Authors: Tracy R P , Currie R M , Young D S 
Published: January 2020

Abstract
Currently we are using two different ISO-DALT two-dimensional gel electrophoresis systems, designated MC-Iso 1 and MC-Iso 2, for the analysis of serum and plasma samples. Here we report quality-assurance data for both of these systems. CV values for the slopes of the pH gradient (ISO dimension) are 5.6% of less; CV values for the slopes of the molecular-mass curves (log Mr vs relative mobility in the DALT dimension) are 3.4% or less. We examined the various steps of the analysis in detail for reproducibility and protein loss, using radiolabeled albumin, alpha 2-macroglobulin, and beta 2-microglobulin. Generally, in the first dimension, less protein enters the MC-Iso 2 gels (our routine system in which silver stain is used) than enters the MC-Iso 1 gels (our wide-range system for myeloma serum samples, in which the gel is stained with Coomassie Blue), on the average, 87% as much. The CV at this stage for both systems is 5--8%. During equilibration, considerable amounts of protein are lost (approximately 30% in 10 min) from the ISO gel, and the reproducibility is also decreased. Resolution in the DALT dimension has, in most cases, little or no effect on either recovery or reproducibility. Overall, for most proteins expected to appear in an ISO gel of a given pH range, approximately 50--60% of the starting material may be expected to reside in the sodium dodecyl sulfate slab gel, under our conditions. The two most important variables affecting recovery are the concentration of the NaOH (used as catholyte) and the pH of the starting sample. The overall CV for the process is between 8 and 12%.
Proteins of human amniotic fluid. II. Mapping by two-dimensional electrophoresis.
Authors: Burdett P , Lizana J , Eneroth P , Bremme K 
Published: January 2020

Abstract
In an earlier study we used various electrophoretic techniques to investigate the proteins in amniotic fluid, including two-dimensional electrophoresis. However, the high proportion of albumin dominated the pattern and tended to distort the pH gradient. Improved methodology, based upon the removal of albumin with Blue Sepharose CL6B and the silver-staining technique, has been used in the present work. These modifications have minimized problems of distortion. We have extended our work in a attempt to complete the two-dimensional map of the proteins in amniotic fluid. Over 200 proteins were seen, ranging in molecular mass from 10 000 to 100 000, including a relatively high proportion of polypeptides of low-molecular mass. The spots seen in the map are discussed in relation to some of the proteins, peptides, and hormones that have been reported in amniotic fluid. Eventually, it is hoped that polypeptides will be found that will provide better indicators of the condition of the fetus.
Proteins of human urine. III. Identification and two-dimensional electrophoretic map positions of some major urinary proteins.
Authors: Edwards J J , Tollaksen S L , Anderson N G 
Published: January 2020

Abstract
We mapped the proteins of human urine by high-resolution two-dimensional electrophoresis, utilizing the ISO-DALT system. Wide-range pH gradients and narrow-range acid gradients were both used in the first-dimension separations. The patterns revealed proteins ranging in relative molecular mass from 10 000 to 90 000. Proteins identified in the map included transferrin, albumin, hemopexin, alpha 2-HS glycoprotein, alpha 1-antitrypsin. Gc globulin, alpha 1-acid glycoprotein, Zn alpha 2-glycoprotein, retinol binding protein, beta 2-microglobulin, the immunoglobulin light chains, and MAUP (most acid urinary protein). The use and utility of internal-charge and molecular-mass standards are described. We used electrophoretic transfer of proteins to nitrocellulose sheets and subsequent detection by immunological methods to identify some proteins.
Familial porphyria cutanea tarda: the pattern of porphyrins formed from porphobilinogen by hemolysates.
Authors: Alleman M A , Wilson J H , van den Berg J W , Edixhoven-Bosdijk A , van Gastel-Quist L M 
Published: January 2020

Abstract
Porphyria cutanea tarda is thought to result from an inherited deficiency of uroporphyrinogen decarboxylase (EC 4.1.1.37) in some patients. Present methods for determining uroporphyrinogen decarboxylase activity are time consuming, so we examined the pattern of porphyrins formed from porphobilinogen by hemolysates as a possible marker for hereditary porphyria cutanea tarda. After the hemolysates are incubated with porphobilinogen, the porphyrins are converted to their methyl esters and examined by liquid chromatography, with fluorometric detection. The porphyrinic patients examined, and some of their relatives, showed a characteristic pattern of porphyrin production, with high uroporphyrin/coproporphyrin and (uroporphyrin + heptacarboxylic porphyrins)/coproporphyrin ratios, at least partly ascribable to increased uroporphyrinogen I synthetase (EC 4.2.1.8) activity in patients' hemolysates, and also to a relative deficiency of uroporphyrinogen decarboxylase. Examination of the pattern of porphyrins produced from porphobilinogen by hemolysates is a suitable technique for detecting asymptomatic individuals with porphyria cutanea tarda.
Quantitation of beta-lipoprotein in cord serum by rate nephelometric immunoassay: a potential screening test for familial hypercholesterolemia.
Authors: Brewster T G , Waite D J , Hudson G A 
Published: January 2020

Abstract
We measured beta-lipoprotein in 232 cord sera by rate nephelometry and compared the results with those obtained by electroimmunoassay. The mean (mean +/- two standard deviations) was 544 (293-1009) mg/L by rate nephelometry and 503 (265-955) mg/L by electroimmunoassay. The between-assay correlation coefficient was 0.891. Between-run coefficients of variation were 3.5-4.4% for nephelometry and 11-14% for electroimmunoassay. Nephelometry was faster, more precise, and less labor intensive than electroimmunoassay. For these reasons, rate nephelometry appears to be a more suitable assay system for mass screening, should detection of familial hypercholesterolemia prove feasible and desirable.
Simplified fluorometry of total metanephrines in urine.
Authors: Christenson R H , McGlothlin C D , Hedrick R , Cate J C 
Published: January 2020

Abstract
We describe a simplified fluorometric method for quantitatively determining metanephrines in urine. The method is based on the elution of metanephrines from an ion-exchange column followed by production of a fluorescent derivative that has excitation and emission maxima of 405 nm and 505 nm, respectively. Metanephrine concentrations as great as 7.0 mg/L were within the linear range of the assay. Analytical recovery of metanephrines was 82-87%. Cross contamination by catecholamines was insignificant. The upper range of normal was 520 micrograms/24 h. Within-run and between-run CV's were 5% and about 9%, respectively. Twenty-four-hour urine specimens from five patients with pheochromocytoma showed above-normal amounts of the metanephrines by this method.
Immune complexes: characteristics, clinical correlations, and interpretive approaches in the clinical laboratory.
Authors: Ritzmann S E , Daniels J C 
Published: January 2020

Abstract
Immune-complex-mediated injury is thought to play a role in diseases such as rheumatoid arthritis, systemic lupus erythematosus, serum sickness, various infectious diseases, and malignancies. With increased appreciation of the biological and pathological significance of circulating immune complexes has come efforts to develop appropriate techniques for identifying and measuring them. Common approaches exploit such phenomena as the attachment of complement components to antigen-antibody complexes, the presence of specialized receptors for immune complexes at the surface of cells, and the ability of rheumatoid factor to bind with immune complexes. This variety of assay systems for immune complexes has yielded abstruse results in numerous human pathological conditions. Unfortunately, these results seldom correlate with one another in a given disease. Thus, use of a panel of immune complex assays has been recommended. Indirect consequences of immune complex disease may still be appraised and evaluated with some confidence in clinical medicine: measurements of C3 and C4, cryoglobulins, serum viscosity, and turbidity of serum samples. Measurement of immune complexes may be useful in diagnosis, prognosis, and therapeutic monitoring, but it is the characterization of immune complexes that holds the greatest potential for better understanding of disease mechanisms.
Oxygen dissociation curves for whole blood, recorded with an instrument that continuously measures pO2 and sO2 independently at constant t, pCO2, and pH.
Authors: Zwart A , Kwant G , Oeseburg B , Zijlstra W G 
Published: January 2020

Abstract
We describe a method for recording oxygen dissociation curves for whole-blood specimens. The blood sample is placed in a thermostated measuring chamber, and pO2 and SO2 are measured continuously by polarography and by reflectometry, respectively. During the recording of an oxygen dissociation curve, the pO2 and SO2 signals are stored in a data-acquisition system, while pH, pCO2, and temperature are kept constant. Determination of precision and error discussion indicated that the coefficient of variation (CV) of the determination of the oxygen dissociation curve is mainly determined by the error in the measurement of SO2. The overall CV of pO2 values belonging to the lower, mid-, and upper parts of the SO2 range is estimated to be about 2.6, 3.1, and 2.1%, respectively. In practice the measurements are about 30% more precise than estimated. With our method, the fixed-acid-induced Bohr effect (H+ factor) can be determined over the entire SO2 range with much greater precision than hitherto.
Dexamethasone suppression of adrenocortical function.
Authors: Sharp A M , Handelsman D J , Ristuccia R M , Turtle J R 
Published: January 2020

Abstract
To investigate the potency of dexamethasone in suppressing adrenocortical function, we gave various evening doses to laboratory staff members. Plasma corticotropin, cortisol, and dehydroepiandrosterone sulfate concentrations were measured the following day, to quantitate the degree of suppression after both short- and long-term treatments. We found that the minimum amount for effective suppression was 1 mg for a single evening dose, 0.5 mg per day for a long-term evening dose. On these regimens plasma corticotropin and cortisol were consistently suppressed, but plasma dehydroepiandrosterone sulfate was suppressed only with long-term treatment.
The Hycel-M multichannel analyzer--a model for evaluation.
Authors: Arntsen K W , Deacon A C , Worth H G 
Published: January 2020

Abstract
We evaluated the Hycel-M Multichannel Analyzer on behalf of the British Department of Health and Social Security. The purpose of the evaluation was to determine the precision of the instrument over a prolonged period of time, to compare its results with those of well-tried laboratory procedures, and to determine how the instrument would perform under the rigors of routine analysis. In addition, experiments were designed and carried out to test specifically certain new features of the instrument. Some new approaches to the analysis of the data generated have been examined and are discussed. The findings are presented as a demonstration of an evaluation procedure.
Hydrolysis by human alpha-amylase of p-nitrophenyloligosaccharides containing four to seven glucose units.
Authors: David H 
Published: January 2020

Abstract
Kinetic and "high-pressure" liquid-chromatographic studies were performed on the reaction of human pancreatic and salivary alpha-amylase (EC 3.2.1.1) with p-nitrophenyloligosaccharides containing four to seven glucose units. The kinetic studies indicate that, as the temperature increases from 25 to 37 degrees C, the apparent Km of the enzyme for a given substrate increases slightly. However, as the number of glucose units in the substrate increases, the apparent Km decreases. The apparent Vmax increases as the temperature increases, and decreases as the number of glucose units in the substrate increases. In contrast, chromatographic data indicate that the relative rate of hydrolysis by alpha-amylase is pG7 greater than pG6 greater than pG5 greater than pG4. The differences between the kinetic and the chromatographic results are discussed. p-Nitrophenyl-alpha-maltopentaoside and p-nitrophenyl-alpha-maltohexaoside are superior to the other p-nitrophenyloligosaccharides as substrates for determining alpha-amylase activity in an alpha-glucosidase-coupled assay system.