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Aminocaproic Acid (aminocaproic + acid)
Selected AbstractsDetermination of ethyl glucuronide in human serum by hyphenation of capillary isotachophoresis and zone electrophoresisELECTROPHORESIS, Issue 8 2008Michaela Nováková Abstract The determination of ethyl glucuronide (EtG), a marker of recent alcohol consumption, in human serum by hyphenation of capillary ITP (CITP) and CZE is reported. For CITP step, 1×10,2,M hydrochloric acid adjusted with ,-aminocaproic acid (EACA) to pH,4.4 was used as the leading electrolyte, and 1×10,2,M nicotinic acid with EACA, pH,4.4, was used as the terminating electrolyte (TE). All electrolytes contained 0.2% hydroxypropylcellulose to suppress electroosmosis. In CITP, EtG was separated from fast serum macrocomponents chloride, phosphate, lactate, and acetate. Zones of microcomponents including EtG that migrated between acetate and nicotinate were forwarded to the second capillary filled with a BGE identical with the TE. Conductivity detection was used in the CITP step. Sensitive detection in the CZE step was performed using indirect spectrophotometric detection at 254,nm. The assay is based on a 1:5 dilution of serum with deionized water and has a concentration LOD for EtG in diluted sample of 9.8×10,9,M. The method was used for the determination of EtG in sera of volunteers consuming alcohol. [source] Effects of lactate and acetate on the determination of serum ethyl glucuronide by CZEELECTROPHORESIS, Issue 23 2006Michaela Mrázková Abstract The analysis of ethyl glucuronide,(EtG), a marker of recent alcohol consumption, in serum with an optimized CZE assay is reported. The method uses a 0.1-mm,id fused-silica capillary of 50,cm effective length that is coated with linear polyacrylamide, a pH,4.4 nicotinic acid/,-aminocaproic acid (EACA) BGE, reversed polarity and indirect analyte detection. The assay is based on a 1:1 dilution of serum with deionized water and has LODs for EtG, lactate and acetate of 3.8×10,7,M, 2.60×10,6,M and 2.18×10,6,M, respectively. Separation of EtG from endogenous macro- and microcomponents (anionic serum components of high and low concentration, respectively) and its quantification are shown to be possible for a wide range of lactate (stacker) and acetate (destacker) concentrations, macrocomponents that have an impact on the CZE behavior of EtG and that change after intake of ethanol. The assay has been successfully applied to the analysis of EtG, lactate and acetate in (i),sera of volunteers that ingested known amounts of alcohol and (ii),samples of patients that were classified (teetotalers and social drinkers vs. alcohol abusers) via analysis of carbohydrate-deficient transferrin. [source] Formation of [b3 , 1 + cat]+ ions from metal-cationized tetrapeptides containing ,-alanine, ,-aminobutyric acid or ,-aminocaproic acid residuesJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 11 2008Sandra M. Osburn Abstract The presence and position of a single ,-alanine (,A), ,-aminobutyric acid (,ABu) or ,-aminocaproic acid (Cap) residue has been shown to have a significant influence on the formation of bn+ and yn+ product ions from a series of model, protonated peptides. In this study, we examined the effect of the same residues on the formation of analogous [b3 , 1 + cat]+ products from metal(Li+, Na+ and Ag+)-cationized peptides. The larger amino acids suppress formation of b3+ from protonated peptides with general sequence AAXG (where X = ,-alanine, ,-aminobutyric acid or ,-aminocaproic acid), presumably because of the prohibitive effect of larger cyclic intermediates in the ,oxazolone' pathway. However, abundant [b3 , 1 + cat]+ products are generated from metal-cationized versions of AAXG. Using a group of deuterium-labeled and exchanged peptides, we found that formation of [b3 , 1 + cat]+ involves transfer of either amide or ,-carbon position H atoms, and the tendency to transfer the atom from the ,-carbon position increases with the size of the amino acid in position X. To account for the transfer of the H atom, a mechanism involving formation of a ketene product as [b3 , 1 + cat]+ is proposed. Copyright © 2008 John Wiley & Sons, Ltd. [source] Novel, cell-penetrating molecular transporters with flexible backbones and permanently charged side-chainsJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 8 2007N. Bodor Various cell-penetrating peptides have been discovered recently that can translocate across plasma membranes and can even carry large cargo molecules into the cells. Because under physiological conditions most of these peptides carry considerable positive charges due to the presence of basic amino acids such as arginine, we decided to investigate whether molecular transporters composed of permanently charged side-chains also possess such cell penetrating ability. Arginine-rich oligomers that have a backbone with increased flexibility due to incorporation of non-,-amino acids (,-aminocaproic acid) have been found to be effective molecular transporters. Here, we report the preparation of analogue structures by replacing the arginine residues with the quaternary form of a novel redox amino acid (Nys+) that contain a trigonelline moiety; it has already been shown possible to replace the original basic amino acid side-chain of neuropeptides without significant activity-loss due to the sufficiently close steric and electronic analogy between the new Nys+ and the original side-chains (in their protonated form, e.g., Arg+, Lys+). A nonamer analogue showed transporter activity resulting in increased cellular uptake in human carcinoma (HeLa) cells. [source] Near-fatal uterine hemorrhage during induction chemotherapy for acute myeloid leukemia: A case report of bilateral uterine artery embolizationAMERICAN JOURNAL OF HEMATOLOGY, Issue 2 2004John T. Phelan II Abstract Severe transfusion-dependent uterine hemorrhage is a relatively uncommon complication of induction chemotherapy for acute myeloid leukemia (AML). Even less common is the failure of systemic conjugated estrogens in this setting. We report a case of life-threatening uterine hemorrhage in a 38-year-old woman in the setting of transfusion-refractory thrombocytopenia after completing induction chemotherapy for AML. She experienced dramatic breakthrough uterine hemorrhage despite multiple platelet transfusions, conjugated estrogens, recombinant factor VIIa, ,-aminocaproic acid, and intracavitary thrombin-soaked gauze tamponade. At the point of near-exsanguination in the setting of hypotension, hematocrit of 14%, and a platelet count of 3,000/,L, she underwent bilateral uterine artery embolization which proved immediately successful. We review the literature and indications for this procedure in the oncologic patient care setting. Am. J. Hematol. 77:151,155, 2004. © 2004 Wiley-Liss Inc. © 2004 Wiley-Liss, Inc. [source] Collision-induced dissociation of protonated tetrapeptides containing , -alanine, , -aminobutyric acid, , -aminocaproic acid or 4-aminomethylbenzoic acid residues,RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 22 2006Erach R. Talaty The influence of the presence and position of a single , -alanine, , -aminobutyric acid, , -aminocaproic acid or 4-aminomethylbenzoic acid residue on the tendency to form b - and y -type product ions was determined using a group of protonated tetrapeptides with general sequence XAAG, AXAG and AAXG (where X refers to the position of amino acid substitution). The hypothesis tested was that the ,alternative' amino acids would influence product ion signal intensities by inhibiting or suppressing either the nucleophilic attack or key proton transfer steps by forcing the adoption of large cyclic intermediates or blocking cyclization altogether. We found that specific b ions are diminished or eliminated completely when ,A, ,Abu, Cap or 4AMBz residues are positioned such that they should interfere with the intramolecular nucleophilic attack step. In addition, differences in the relative proton affinities of the alternative amino acids influence the competition between complementary bn and yn ions. For both the AXAG and the XAAG series of peptides, collision-induced dissociation (CID) generated prominent b ions despite potential inhibition or suppression of intramolecular proton migration by the ,A, ,Abu, Cap or 4AMBz residues. The prominent appearance of b ions from the AXAG and XAAG peptide is noteworthy, and suggests either that proton migration occurs through larger, ,whole' peptide cyclic intermediates or that fragmentation proceeds through a population of [M+H]+ isomers that are initially protonated at amide O atoms. Copyright © 2006 John Wiley & Sons, Ltd. [source] The Chemistry of Escapin: Identification and Quantification of the Components in the Complex Mixture Generated by an L -Amino Acid Oxidase in the Defensive Secretion of the Sea Snail Aplysia californicaCHEMISTRY - A EUROPEAN JOURNAL, Issue 7 2009Michiya Kamio Dr. Abstract A complex mixture of products in an enzymatic reaction: Aplysia californica releases amino acid oxidase and its substrate lysine in defensive secretions to produce a mixture of multiple compounds (see figure). Escapin is an L -amino acid oxidase in the ink of a marine snail, the sea hare Aplysia californica, which oxidizes L -lysine (1) to produce a mixture of chemicals which is antipredatory and antimicrobial. The goal of our study was to determine the identity and relative abundance of the constituents of this mixture, using molecules generated enzymatically with escapin and also using products of organic syntheses. We examined this mixture under the natural range of pH values for ink,from ,5 at full strength to ,8 when fully diluted in sea water. The enzymatic reaction likely forms an equilibrium mixture containing the linear form ,-keto-,-aminocaproic acid (2), the cyclic imine ,1 -piperidine-2-carboxylic acid (3), the cyclic enamine ,2 -piperidine-2-carboxylic acid (4), possibly the linear enol 6-amino-2-hydroxy-hex-2-enoic acid (7), the ,-dihydroxy acid 6-amino-2,2-dihydroxy-hexanoic acid (8), and the cyclic aminol 2-hydroxy-piperidine-2-carboxylic acid (9). Using NMR and mass spectroscopy, we show that 3 is the major component of this enzymatic product at any pH, but at more basic conditions, the equilibrium shifts to produce relatively more 4, and at acidic conditions, the equilibrium shifts to produce relatively more 2, 7, and/or 9. Studies of escapin's enzyme kinetics demonstrate that because of the high concentrations of escapin and L -lysine in the ink secretion, millimolar concentrations of 3, H2O2, and ammonia are produced, and also lower concentrations of 2, 4, 7, and 9 as a result. We also show that reactions of this mixture with H2O2 produce ,-aminovaleric acid (5) and ,-valerolactam (6), with 6 being the dominant component under the naturally acidic conditions of ink. Thus, the product of escapin's action on L -lysine contains an equilibrium mixture that is more complex than previously known for any L -amino acid oxidase. [source] Effect of various stabilizing agents on Imperata cylindrica grass pollen allergen extractCLINICAL & EXPERIMENTAL ALLERGY, Issue 1 2003K. M. Bijli Summary Background Allergen extracts are unstable, heat labile or susceptible to proteases. Stability of allergen extracts is important for proper diagnosis and therapy of allergic disorders. Objective The present study was undertaken to determine the preservation and stabilization conditions of Imperata cylindrica (Ic) grass pollen extract. Methods The Ic extract was kept with 0.1 m,-aminocaproic acid (EACA), 0.75 m sucrose, 5% glycerol, 0.03% human serum albumin (HSA) or 0.4% phenol for different time periods. The extracts were stored for 3, 6 and 12 months each at 4 °C, 4 °C with daily exposure to room temperature (RT) for 1 h, and RT. The quality of extracts was analysed by SDS-PAGE, Western blot, ELISA, ELISA inhibition and skin test. Results Extracts kept with EACA and sucrose retained most of the protein bands followed by glycerol as determined by SDS-PAGE and Western blot during all storage periods and conditions in comparison with standard extracts. The extracts kept with HSA, phenol and without preservative (WP) showed protein degradation below 33 kDa after 3 months storage at all conditions. However, a 67-kDa allergen was stable in these extracts. EACA extract required 75 to 120 ng of protein for 50% inhibition in IgE binding under different conditions, whereas standard extract required 70 ng for the same. ELISA also demonstrated high allergenic reactivity of EACA extract. ID test on allergy patients with EACA extract demonstrated same allergenic potency as that of standard extract. Conclusion EACA is the best preservative/stabilizing agent of Ic pollen extract, followed by sucrose and glycerol. Ic extract kept with phenol, HSA and without preservative showed degradation within 3 months. EACA preserved extract is equally potent as that of standard extract up to 1 year's storage. [source] | |||||||||||||