Showing papers on "Elution published in 1976"
TL;DR: The method of alkaline elution provides a sensitive measure of DNA single-strand length distribution in mamalian cells and is applicable to a variety of problems concerning DNA damage, repair, and replication.
Abstract: The method of alkaline elution provides a sensitive measure of DNA single-strand length distribution in mamalian cells and is applicable to a variety of problems concerning DNA damage, repair, and replication. The physical basis of the elution process was studied. The kinetics of elution above the alkaline transition pH were found to occur in two phases: an initial phase in which single-strand length is rate limiting, followed by a phase in which elution is accelerated due to the accumulation of alkali-induced strand breaks. The range of DNA single-strand lengths that can be discriminated by elution above the alkaline transition pH was estimated by calibration relative to the effects of x ray, and was found to be 5 X 10(8)-10(10) daltons. Shorter DNA strands elute within the pH transition zone, which extended from pH 11.3 to 11.7 when tetrapropylammonium hydroxide was used as base. This elution was relatively rapid, but was sharply limited by pH, according to the length of the strands: the length of the strands eluted increased with increasing pH. Alkaline elution was inhibited by treatment of cells with low concentrations of nitrogen mustard, a bifunctional alkylating known to cross-link DNA. On investigation of the possibility that DNA subclasses may differ in their elution behavior, satellite L strands were found to elute more slowly from cells exposed to a low dose of x ray than did the bulk DNA.
866 citations
TL;DR: This paper presents the experience in measurement of plasma angiotensin II concentration according to the method described by Düsterdieck, G. and McElwee, G (1971).
236 citations
TL;DR: A high pressure liquid chromatographic (HPLC) technique for the separation and quantification of three classes of naturally occurring phenolic compounds has been developed in this article, which offers selectivity, resolution, speed, and sensitivity (minimum detectable amounts below 50 ng) far superior to classical techniques such as paper chromatography.
209 citations
195 citations
TL;DR: The analysis of phosphatidylcholine and sphingomyelin present in the lipid extracts from animal tissues, blood and amniotic fluids were made without interference from other phospholipids or ultraviolet-absorbing material.
Abstract: A sensitive method for the separation of phosphatidylcholine and sphingomyelin by high-performance liquid chromatographic analysis is described. The elution of the phospholipids from a microparticulate (10 mum) silica-gel chromatographic column was monitored with an ultraviolet spectromonitor at 203 nm. Acetonitrile/methanol/water (65:21:14, by vol.) was used as the solvent. It was shown by using synthetic phosphatidylcholines of knowm fatty acid composition and of varying degree of unsaturation that the absorption at 203 nm was primarily due to the isolated double bonds and the response measured varied with the degree of unsaturation. Approx. 1 nmol of phosphatidylcholine, containing at least one double bond per molecule, can be detected. The amounts of phosphatidylcholine and sphingomyelin could be determined by high-performance liquid chromatography and ultraviolet absorption if the apparent extinction coefficient of the material analyzed was established. Alternatively, peaks were collected and the phospholipids were determined by the analysis of phosphorus. The analysis of phosphatidylcholine and sphingomyelin present in the lipid extracts from animal tissues, blood and amniotic fluids were made without interference from other phospholipids or ultraviolet-absorbing material. The method described here is complementary to the high-performance liquid chromatographic method described previously for the analysis of ethanolamine-containing phosphoglycerides and serine-containing phosphoglycerides [Jungalwala, Turel, Evans and McCluer (1975) Biochem. J. 145, 517-526].
177 citations
142 citations
TL;DR: An affinity chromatography technique for purifying of α-amylase from triticale (X Triticosecale Wittmack) gives a yield in excess of 90% with a purification of up to 180-fold over crude extracts.
111 citations
TL;DR: The first successful application of ion chromatography (IC) to the analysis of total water soluble sulfate and nitrate in ambient aerosols was described in this article, where conditions and data on sensitivity, selectivity, accuracy and repeatability were described.
Abstract: Ion exchange has been known to provide excellent separation of ions since 1850, and ion exchange chromatography has been in use since 1940. However, ion exchange chromatography has not been widely used for the automated analysis of eluted ions because of the background produced by the electrolyte used for elution. H. Small, T. S. Stevens, and W. C. Bauman, (Anal. Chem., 47, 1801 (1975)) recently developed a technique whereby the background is reduced to a minimum with eluant suppression. Eluant suppression allows the use of ion exchange chromatography with conductimetric detection as a sensitive and selective means for the analysis of practically all ionic species. This communication describes the first successful application of ion chromatography (IC) to the analysis of total water soluble sulfate and nitrate in ambient aerosols. Analytical conditions and data on sensitivity, selectivity, accuracy and repeatability are described. The application of this technique to the analysis of atniospheric ...
108 citations
TL;DR: Good preparative separation of neutral glycolipids of human erythrocytes was achieved by column chromatography using the totally porous silica spheres, Iatrobeads®.
98 citations
TL;DR: Reversed-phase high-pressure liquid chromatography with gradient elution on Zorbax-ODS columns has been used to separate, identify, and measure, spectrophotometrically, the steroids secreted by both human adrenal and testis cells in primary monolayer culture.
94 citations
TL;DR: The results obtained with this method compare favorably with results obtained by gas-liquid chromatography and in over 1300 patients' samples analyzed to date, the only drugs known to have interfered with the assay are gentamicin, diazoxide, and mephobarbital.
Abstract: We describe an assay system for measuring phenobarbital, diphenylhydantoin, primidone, ethosuximide, and carbamazepine in 25 mul of serum. The procedure involves precipitation of proteins with an acetonitrile solution containing cyheptamide as an internal standard, and reverse-phase chromatography on a 4 mm X 30 cm column containing "muBondapak C18." The anticonvulsants are eluted with an equivolume mixture of potassium phosphate buffer (10 mmol/liter, pH 8.0) and acetonitrile at a flow rate of 0.8 ml/min, detected by their absorbance at 200 nm, and quantitated by measuring peak areas. When measurement of primidone is not required, a 254-nm detector may be used. Each analysis requires 10 min. Optimum column temperature has been found to decrease with use. Analytical recoveries for the five drugs varied from 92% to 102% with good precision (coefficients of variation between 2.8% and 9.2% for therapeutic and toxic concentrations). The results obtained with this method compare favorably with results obtained by gas-liquid chromatography (correlation coefficients between 0.77 and 0.98). In over 1300 patients' samples analyzed to date, the only drugs known to have interfered with the assay are gentamicin, diazoxide, and mephobarbital.
TL;DR: A chromatographic system involving a high-performance chemically-bonded reverse-phase column and fluorescence detection for measurement of indoles in urine and controlled retention and selectivity by optimizing the methanol content and pH of the mobile phase.
Abstract: We describe a chromatographic system involving a high-performance chemically-bonded reverse-phase column and fluorescence detection for measurement of indoles in urine. We controlled retention and selectivity by optimizing the methanol content and pH of the mobile phase. Six reference indoles were separated in less than 20 min; three 5-hydroxyindoles were eluted in less than 7 min. About 5-15 ng of aqueous solutions of these compounds can be detected. The combination of selectivity (from use of the chromatographic column) and fluorescence detection permitted analysis for five of the six indoles after a single urine-deproteinization step.
TL;DR: This procedure has advantages over other ion-exchange column separations of nucleotides in that the nucleotide elute in a small volume and that LiCl, which is used to elute theucleotides, does not interfere with the determination of radioactivity by liquid scintillation counting.
TL;DR: Quantitative analyses can be carried out by high-performance liquid chromatography, using appropriate internal standards, and excretion patterns in the various types of porphyria can be obtained which may facilitate clinical diagnosis more effectively than the earlier qualitative thin-layer chromatographic methods.
TL;DR: Salt-mediated hydrophobic chromatography, a technique by which hydrophilic interactions of a protein with a given ligand coupled to Sepharose are enhanced by specific salts, was used for human IgA purification.
TL;DR: In this paper, the optimal conditions for using high-performance liquid chromatography (HPLC) in the size exclusion mode have been determined for measuring the molecular-weight (MW) distribution of chitosan samples.
TL;DR: The purification achieved in analyses of plasma permits solid injection of the equivalent of 1-2 ml of plasma without overloading of the capillary column.
TL;DR: From the similarity in the elution patterns, translational diffusion coefficient, and near ultraviolet CD wavelength profiles of the bovine and the human low molecular weight α-crystallin, it can be concluded that, in spite of some differences in amino acid composition, both fractions possess similar secondary and tertiary structures.
TL;DR: Human fibroblast and mouse L929 cell interferons can be purified by adsoprtion to and subsequent elution from Controlled Pore Glass, with good recovery of activity.
Abstract: Summary
Human fibroblast and mouse L929 cell interferons can be purified by adsorption to and subsequent elution from Controlled Pore Glass. Purification of 40 to 90-fold to specific activities of 1 to 5 × 106 units/mg of protein can be achieved in a single step, with good recovery of activity. Human leukocyte interferon does not bind to the glass and cannot be purified in this way.
TL;DR: Thin layer chromatography of drugs following conventional XAD-2 and column extraction, demonstrates identical qualitative results, but shows higher purity of the column extracts, which are superior to conventional extraction.
TL;DR: This method has been used to determine the levles of putrescine, spermidine and spermine in various tissues of rats and in L 1210 leukemic cells of mice grown in culture.
TL;DR: A high-performance liquid chromatographic method for the measurement of daunomycin and its main metabolite, daunaomycinol, at low concentrations in plasma is described and quantitative determinations were obtained by the use of adriamycin, another cystostatic anthracycline antibiotic, as an internal standard.
TL;DR: In this article, a simple, direct, gas chromatograph (GC) technique was described for eluting flavor-related volatile components from commercially produced vegetable oils, where a sample of oil was placed onto glass wool contained in a GC liner, and the liner was inserted in the heated inlet of the GC.
Abstract: A simple, direct, gas chromatograph (GC) technique is described for eluting flavor-related volatile components from commercially produced vegetable oils. A sample of oil was placed onto glass wool contained in a GC liner, and the liner was inserted in the heated inlet of the GC. Volatiles from the oils were rapidly eluted by heat and carrier gas onto the GC column. Profiles of the volatiles were obtained by temperature-programmed gas chromatography. Flavor score was highly correlated with individual volatile components considered separately, and very highly correlated with multiple volatile components considered together, indicating that reliable flavor characteristics of vegetable oils may be obtained rapidly and efficiently by instrumentation.
TL;DR: The size of dissolved polymers can be estimated a priori at infinite dilution and under theta conditions from existing theories by assuming that the hydrodynamic volume decreases from a maximum value at infinity dilution toward the theta condition volume, which is reached when the volume fraction of solvated polymer in solution is unity as discussed by the authors.
Abstract: The sizes of dissolved polymers can be estimated a priori at infinite dilution and under theta conditions from existing theories. The effects of concentration can be calculated by assuming that the hydrodynamic volume decreases from a maximum value at infinite dilution toward the theta condition volume, which is reached when the volume fraction of solvated polymer in solution is unity. The predicted hydrodynamic volumes coincide with results of small-angle x-ray scattering and effects of solvent and concentration on gel permeation chromatography elution volumes.
TL;DR: Physico-chemical characterization revealed that herbicidins are new antibiotics having an adenine nucleoside moiety in their structures.
Abstract: Herbicidins were produced in submerged fermentation by Streptomyces saganonensis. Isolation of the antibiotics from the culture broth was performed by adsorption on resinous adsorbent followed by elution with aqueous acetone. Herbicidins A and B were separated from each other by counter-current distribution on a Ronor column or by silica gel chromatography. Physico-chemical characterization revealed that herbicidins are new antibiotics having an adenine nucleoside moiety in their structures.
TL;DR: In this paper, an optically active macromolecular chromatographic packing from cross-linked polyacrylamide grafted with α-amino acid was synthetized for high pressure liquid chromatography.
Abstract: We have synthetized an optically active macromolecular chromatographic packing from cross-linked polyacrylamide grafted with an optically active α-amino acid. This packing, in the form of small beads, slightly swells in water. Its granularity, porosity and rigidity are suitable for high pressure liquid chromatography. Such packings, complexed by a metallic ion, are efficient for the resolution of many underivatized racemic α-amino acids by elution with water. As an example, on one of these packings, containing Cu++ ions, enantiomers of valine, threonine, isoleucine, serine, phenylalanine, tyrosine, tryptophan, and asparagine are completely resolved in less than one hour.
TL;DR: High-pressure liquid chromatography, utilizing reverse phase μ Bondapak C18 columns and elution with increasing acetonitrile concentrations, has been used to resolve amino acid phenylthiohydantoins obtained from the automated Edman degradation of proteins.
TL;DR: Alpha-toxin, purified by glass bead chromatography, is composed of a single electrophoretic form, containing less than 2% of other forms.
Abstract: Staphylococcal alpha-toxin was purified from Staphylococcus aureus growth medium using adsorption chromatography on controlled pore glass beads. Elution of alpha-toxin from the unmodified glass surface of the beads with various anions generally followed the chaotropic series. Alpha-toxin, purified by glass bead chromatography, is composed of a single electrophoretic form, containing less than 2% of other forms.
TL;DR: The proposed mechanisms of citrate synthase, obtained from steady state kinetics, were examined in light of the elution pattern of the enzyme obtained using combinations of substrates and substrate analogs.