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9199789 | Adhesion-induced domain formation by interplay of long-range repulsion and short-range attraction force: a model membrane study. | We study the role of the interplay of specific and universal forces for the adhesion of giant vesicles on solid supported membranes. To model the situation of cell adhesion, we incorporated lipopolymers (phospholipids with polyethyleneoxide headgroups) as artificial glycocalix, whereas attractive lock-and-key forces ar... |
9199788 | Effect of changing the size of lipid headgroup on peptide insertion into membranes. | Adsorption of amphiphilic peptides to the headgroup region of a lipid bilayer is a common mode of protein-membrane interactions. Previous studies have shown that adsorption causes membrane thinning. The degree of the thinning depends on the degree of the lateral expansion caused by the peptide adsorption. If this simpl... |
9199787 | Zero-order interfacial enzymatic degradation of phospholipid tubules. | The first study of enzymatic hydrolysis of phospholipid tubules is reported. Phosphatidylcholines with acyl chains containing diacetylene groups are known to form tubular microstructures in which the lipids are tightly packed and crystalline. These tubules can be used to probe the role of microstructural form in the me... |
9199777 | Extension of torsionally stressed DNA by external force. | Metropolis Monte Carlo simulation was used to study the elasticity of torsionally stressed double-helical DNA. Equilibrium distributions of DNA conformations for different values of linking deficit, external force, and ionic conditions were simulated using the discrete wormlike chain model. Ionic conditions were specif... |
9199774 | Estimation of the diffusion-limited rate of microtubule assembly. | Microtubule assembly is a complex process with individual microtubules alternating stochastically between extended periods of assembly and disassembly, a phenomenon known as dynamic instability. Since the discovery of dynamic instability, molecular models of assembly have generally assumed that tubulin incorporation in... |
9199768 | Collective properties of hydration: long range and specificity of hydrophobic interactions. | We report results of molecular dynamics (MD) simulations of composite model solutes in explicit molecular water solvent, eliciting novel aspects of the recently demonstrated, strong many-body character of hydration. Our solutes consist of identical apolar (hydrophobic) elements in fixed configurations. Results show tha... |
9199299 | Intra- and intermolecular cooperative binding of high-mobility-group protein I(Y) to the beta-interferon promoter. | The mammalian high-mobility-group protein I(Y) [HMG I(Y)], while not a typical transcriptional activator, is required for the expression of many eukaryotic genes. HMG I(Y) appears to recruit and stabilize complexes of transcriptional activators through protein-DNA and protein-protein interactions. The protein binds to ... |
9196224 | Expression and self-assembly of recombinant capsid protein from the antigenically distinct Hawaii human calicivirus. | The Norwalk and Hawaii viruses are antigenically distinct members of the family Caliciviridae and are considered to be important etiologic agents of epidemic gastroenteritis, with most studies focusing on the role of Norwalk virus. To further investigate the importance of Hawaii virus, Hawaii virus-like particles (VLPs... |
9196168 | A subtype-specific peptide-based enzyme immunoassay for detection of antibodies to the G protein of human respiratory syncytial virus is more sensitive than routine serological tests. | Peptides deduced from the central conserved region (residues 158 to 189) of protein G of human respiratory syncytial virus (HRSV) subtypes A and B were used as antigens in subtype-specific enzyme-linked immunosorbent assays (G-peptide ELISAs). These G-peptide ELISAs were compared with seven other serological assays to ... |
9188618 | Increase in the frequency of hepadnavirus DNA integrations by oxidative DNA damage and inhibition of DNA repair. | Persistent hepadnavirus infection leads to oxidative stress and DNA damage through increased production of toxic oxygen radicals. In addition, hepadnaviral DNA integrations into chromosomal DNA can promote the process of hepatocarcinogenesis (M. Feitelson, Clin. Microbiol. Rev. 5:275-301, 1992). While previous studies ... |
9188574 | A mechanism for negative gene regulation in Autographa californica multinucleocapsid nuclear polyhedrosis virus. | The Autographa californica multinucleocapsid nuclear polyhedrosis virus (AcMNPV) ie-1 gene product (IE-1) is thought to play a central role in stimulating early viral transcription. IE-1 has been demonstrated to activate several early viral gene promoters and to negatively regulate the promoters of two other AcMNPV reg... |
9188571 | Specific targeting to CD4+ cells of recombinant vesicular stomatitis viruses encoding human immunodeficiency virus envelope proteins. | We generated replication-competent, recombinant vesicular stomatitis viruses (VSVs) expressing the human immunodeficiency virus (HIV) envelope protein or an HIV-VSV chimeric envelope protein in which the cytoplasmic domain of the HIV envelope protein was replaced with that from the VSV glycoprotein (G). These recombina... |
9185566 | A macrocyclic bis-acridine shifts the equilibrium from duplexes towards DNA hairpins. | Nucleic acids can undergo dynamic conformational changes associated with the regulation of biological processes. A molecule presenting larger affinities for alternative structures relative to a duplex is expected to modify such conformational equilibria. We have previously reported that macrocyclic bis-acridine binds p... |
9627831 | Use of capillary electrophoresis in the characterization of sulfonated metallophthalocyanines: a comparative evaluation of purification procedures following synthesis by the condensation method. | Capillary electrophoresis has been presented as a resourceful technique for monitoring the purity of synthetic metallophthalocyanines and evaluating comparatively purification procedures. In this study, the tetrasulfonated cobalt(II) phthalocyanine was synthesized by the condensation method and submitted to several pur... |
21639261 | Molecular Baskets in Supercritical CO(2). | Calixarenes are synthetic macrocyclic compounds, described as "molecular baskets" as they possess high ionophoric selectivity and form inclusion complexes with many important ionic guests. In our initial work, hexameric and tetrameric tert-butylcalixarenes, unfunctionalized at the lower rim, are shown to be separable o... |
21639257 | Spectroscopic determination of pressure-induced shifts in inclusion complexation equilibria. | The effect of modest hydrostatic pressure (<350 bar) on condensed-phase equilibrium processes has been largely overlooked, due in large part to the small compressibility of these phases relative to gases or supercritical fluids. Although the bulk properties of condensed phases are not significantly modified by pressure... |
18966826 | Kinetic determination of organic vapor mixtures with single piezoelectric quartz crystal sensor using artificial neural networks. | A single piezoelectric quartz crystal coated with one kind of crown ether was applied to the simultaneous determination of binary acid and amine vapor mixtures. From the adsorption and desorption curves of analytes, which were somewhat different in shape, frequency shifts from ten time windows were taken as inputs for ... |
18966825 | Cyclodextrin enhanced fluorimetric determination of malonaldehyde by the thiobarbituric acid method. | The enhancement effects of alpha-, beta-, gamma;- and hydroxypropyl-beta-cyclodextrins on the fluorescence of a 2:1 thiobarbituric acid/malonaldehyde adduct in acid aqueous solutions have been studied. The best characteristics as a fluorescence enhancement agent showed hydroxypropyl-beta-cyclodextrin which bound the ad... |
9241195 | Adsorption and Recovery of Ionic Surfactants by beta-Cyclodextrin Polymer | The adsorption and recovery of ionic surfactants, such as dodecylbenzenesulfonic acid (DBS) and benzalkonium chloride (BKC), from an aqueous solution were studied using the beta-cyclodextrin polymer (beta-CDP). BKC always demonstrated a higher adsorption efficiency than DBS in batch tests, isotherms, and column tests. ... |
11669926 | Linear Chain Formation by an Oxovanadium(V) Complex of p-Methylhexahomotrioxacalix[3]arene. | The oxovanadium(V) complex 4 can be readily synthesized by the reaction of the lithium salt of p-methylhexahomotrioxacalix[3]arene trianion 3 with VOCl(3). Infrared spectra indicate a terminal V=O for complex 4 in solution and V=O.V dative interactions in the solid state consistent with the formation of a &mgr;-oxo-bri... |
11669923 | Electrochemical, Spectroscopic, and Spectroelectrochemical Properties of Synthetically Useful Supramolecular Light Absorbers with Mixed Polyazine Bridging Ligands. | The trimetallic complexes [{(bpy)(2)M(dpp)}(2)Ru(dpq)](6+) (M = Ru(II) or Os(II), bpy = 2,2'-bipyridine, dpp = 2,3-bis(2-pyridyl)pyrazine, and dpq = 2,3-bis(2-pyridyl)quinoxaline) have been prepared and the details of their spectroscopic, electrochemical, and spectroelectrochemical properties investigated. These mixed ... |
11669919 | Exchange Coupling in an Isostructural Series of Face-Sharing Bioctahedral Complexes [LM(II)(&mgr;-X)(3)M(II)L]BPh(4) (M = Mn, Fe, Co, Ni, Zn; X = Cl, Br; L = 1,4,7-Trimethyl-1,4,7-triazacyclononane). | The reaction of the divalent metal halides ZnCl(2), ZnBr(2), MnCl(2).4CH(3)CN, MnBr(2), FeCl(2).4CH(3)CN, CoCl(2).4CH(3)CN, CoBr(2), NiCl(2).6H(2)O, and NiBr(2), respectively, with the macrocycle 1,4,7-trimethyl-1,4,7-triazacyclononane (L) (1:1) in anhydrous acetonitrile, acetone, chloroform, or ethanol affords upon ad... |
11669911 | Templating and Clipping Coordination Reactions Leading to Heteronuclear Trimetallic Complexes Containing Interlocking Rings. | We report the preparation of heterotrimetallic complexes with a Cu-complexed [2]-catenate structure, containing two other metals within the rings. Starting from a multidentate ligand 1 containing two terpy units (terpy 2,2':6',2"-terpyridine) and one dpp fragment (dpp 2,9-diphenyl-1,10-phenanthroline), a 29-membered ma... |
11669907 | Dynamic Cis-Trans Bridge Isomerism in the Cyclidene Family of Dioxygen Carriers: A Bicyclic Cyclidene with a Trans Bridge Orientation. | A new type of isomerism has been detected in the cyclidene family of lacunar dioxygen carriers, providing an additional structural variable for the control of their oxygen affinity. In those rare complexes that do not have methyl substituents on the primary macrocycle, NMR and X-ray crystallographic data indicate that,... |
11669902 | Migratory Transmetalation in Diphenoxo-Bridged Cu(II)M(II) Complexes of a Dinucleating Macrocycle with N(amine)(2)O(2) and N(imine)(2)O(2) Metal-Binding Sites. | A phenol-based heterodinucleating macrocycle (H(2)L), comprised of two 2-((methylamino)methyl)-6-(iminomethyl)-4-bromophenolate entities bridged by the -(CH(2))(2)- groups between amine nitrogens and by the -(CH(2))(3)- groups between imine nitrogens, displays dissimilar N(amine)(2)O(2) and N(imine)(2)O(2) metal-bindin... |
9425742 | Action of K-crown ether on photosystem II electron transport: characterization of the site of action. | We have investigated the inhibitory effect of K-crown (18-crown-6 potassium picrate) on photosystem II (PSII)-enriched membrane fragments and O2-evolving core complexes. K-crown at 2-4 microM inhibits about half the control level of O2-evolution activity in both types of PSII samples. Oxygen-evolution studies demonstra... |
9378812 | Itraconazole solution: higher serum drug concentrations and better clinical response rates than the capsule formulation in acquired immunodeficiency syndrome patients with candidosis. | <h4>Aims</h4>To compare the serum concentrations of itraconazole and hydroxyitraconazole after treatment with itraconazole cyclodextrin solution and itraconazole capsules in human immunodeficiency virus (HIV) positive patients with oral candidosis.<h4>Methods</h4>The pharmacokinetics of itraconazole and its active meta... |
9330202 | Influence of hydroxypropyl beta-cyclodextrin on the stability of benzylpenicillin in chloroacetate buffer. | Hydroxypropyl beta-cyclodextrin (HP beta CyD) has been shown to stabilize a wide variety of chemically distinct pharmaceutical entities through inclusion-complex formation between drug and cyclodextrin. The effect of HP beta CyD on the acid-catalysed hydrolysis of benzylpenicillin (penicillin G) was evaluated in chloro... |
9276930 | Applications of S-layers. | The wealth of information existing on the general principle of S-layers has revealed a broad application potential. The most relevant features exploited in applied S-layer research are: (i) pores passing through S-layers show identical size and morphology and are in the range of ultrafiltration membranes; (ii) function... |
9333959 | [Follow-up and prognosis of severe accidental trauma in the aged]. | Multiple injuries in elderly patients are still a common problem. The present study was performed to investigate mortality and complications in multiple trauma patients aged 65 years or more. A total of 1154 multiple trauma patients with an injury severity score (ISS) of at least 18 points were divided in two age group... |
9244455 | Analysis of NORs and NOR-associated heterochromatin in the mussel Mytilus galloprovincialis Lmk. | The chromosomes of the mussel Mytilus galloprovincialis were analysed by means of chromomycin A3 (CMA), distamycin A/DAPI (DA/DAPI), DAPI/actinomycin D (DAPI/AMD) and chromomycin A3/distamycin A/DAPI (CDD) fluorescence banding techniques, C-banding, silver staining, N-banding and in situ hybridization with 18S+28S rDNA... |
9244454 | Fluorescence in situ hybridization of ribosomal DNA to mitotic chromosomes of tsetse flies (Diptera: Glossinidae: Glossina). | Ribosomal genes were mapped in Glossina austeni, G. brevipalpis, G. f. fuscipes, G. m. submorsitans, G. p. palpalis, G. pallidipes and G. tachinoides on mitotic chromosomes by fluorescence in situ hybridization (FISH) using Drosophila hydei genomic clones that contain the 28S ribosomal DNA. In all species except G. bre... |
9244453 | Zoo-fluorescence in situ hybridization analysis of human and Indian muntjac karyotypes (Muntiacus muntjak vaginalis) reveals satellite DNA clusters at the margins of conserved syntenic segments. | Zoo-fluorescence in situ hybridization (FISH) with human whole chromosome-specific paint probes revealed extensive homoeologies between Indian muntjac (2n=6, 7 female, male) and human karyotypes (2n=46). Forty-two conserved syntenic segments, corresponding to all human chromosomes except the Y chromosome, produced a ne... |
9244452 | Application of three different methods to analyse fibre-FISH results obtained using four lambda clones from the porcine MHC III region. | Four lambda clones (lambda G11, lambda C4, lambda G14 and lambda G17) from the porcine MHC class III region were labelled with either biotin-14-dATP or digoxigenin-11-dUTP and hybridized in two different combinations to DNA fibres. The latter were prepared from agarose-embedded porcine peripheral lymphocytes lysed with... |
9244451 | Multiple repetitive DNA sequences in the paracentromeric regions of Arabidopsis thaliana L. | Nine repetitive DNA sequences, present in the haploid Arabidopsis thaliana genome in 7-300 copies, were hybridized in situ to metaphase and interphase chromosomes. Every sequence was detected on all five chromosome pairs, but was not evenly dispersed over the genome. Clusters of signals were found in particular regions... |
9244450 | Differences of histone H4 acetylation and replication timing between A and B chromosomes of brachycome dichromosomatica. | Differences are demonstrated between A (transcriptionally active) and B (transcriptionally inactive) chromosomes that are characterized by a different level of histone H4 acetylation and a different timing of DNA replication. These differences between the chromatin of A and B chromosomes were found after immunolabellin... |
9244449 | Telomeric sequences localization and G-banding patterns in the identification of a polymorphic chromosomal rearrangement in the rodent Akodon cursor (2n=14,15 and 16). | Akodon cursor is an exceptional example of high chromosomal variability, displaying diploid numbers from 14 to 16 and fundamental numbers (FN) from 18 to 26 as the result of a complex rearrangement in par 1 and pericentric inversions in three autosomal pairs. The difference in the diploid number is due to the presence ... |
9244448 | Polymorphism of the nucleolus organizer region (NOR) on the putative sex chromosomes of Arctic char (Salvelinus alpinus) is not sex related. | Polymorphism of the nucleolus organizer region (NOR) on the putative sex chromosomes of Arctic char (Salvelinus alpinus) was examined using conventional cytogenetic and molecular techniques. Variation was observed in the number, size and position of rDNA loci on the sex pair. Fluorescence in situ hybridization (FISH) a... |
9244447 | Isolation of DNA from the centromere of human chromosome 7 by microdissection. | Centromeres remain the least characterized regions of human chromosomes because they have a very high content of repetitive DNA. Here, we describe a microdissection library from the centromeric region of human chromosome 7 and its use for generating sequence tagged sites (STSs). The library contains about 1500 clones w... |
9241777 | Toxins and genes isolated from scorpions of the genus Tityus. | Scorpion venoms contain a variety of low mol. wt peptides toxic to different organisms. These peptides have been intensively studied because they represent excellent models for investigating structure-function relationships and they are also fine probes for studying ionic channel functions. This review deals with the b... |
9237682 | Evidence for a crosslink between c-heme and a lysine residue in cytochrome P460 of Nitrosomonas europaea. | Cytochrome P460 and hydroxylamine oxidoreductase (HAO) of Nitrosomonas europaea catalyze the oxidation of hydroxylamine. Cytochrome P460 contains an unidentified heme-like chromophore whose distinctive spectroscopic properties are similar to those for the P460 heme found in HAO. The heme P460 of HAO has previously been... |
9237574 | Sulfobutylether-beta-cyclodextrin-mediated capillary electrophoresis for separation of chlorinated and substituted phenols. | Cyclodextrin-mediated capillary electrophoresis has been developed for separation and analysis of chlorinated as well as substituted phenolic compounds. The procedure used a negatively charged sulfobutylether-beta-cyclodextrin (SB-betaCD) to effect differential partitioning of the phenols between the buffer and CD phas... |
9234866 | High-performance liquid chromatographic assay for methyl-beta-cyclodextrin in plasma and cell lysate. | This paper describes a high-performance liquid chromatographic method with fluorescence detection for the analysis of methyl-beta-cyclodextrin (MEBCD) in plasma and cell lysate, after in situ complexation with 1-naphthol. The size-exclusion HPLC column packed with TSK 3000 SW gel, was equilibrated with an eluent mixtur... |
9231029 | Effects of renin inhibition compared to angiotensin converting enzyme inhibition in conscious dogs with pacing-induced heart failure. | <h4>Objective</h4>To compare the effects of angiotensin converting enzyme inhibition (ACEI) (captopril 1 mg/kg i.v.) to direct renin inhibition (CP80794 3 mg/kg i.v.) on left ventricular and systemic hemodynamics and peripheral blood flows in advanced congestive heart failure (CHF).<h4>Methods</h4>Conscious chronically... |
9230933 | Annexin V interactions with collagen. | Annexin V was originally identified as a collagen-binding protein called anchorin CII and was isolated from chondrocyte membranes by affinity chromatography on native type II collagen. The binding of annexin V to native collagen type II is stable at physiological ionic strength when annexin V is reconstituted in liposo... |
9228803 | Enantioseparation using selected polysaccharides as chiral buffer additives in capillary electrophoresis. | Selected water-soluble, native polysaccharides--such as amylose, laminaran, pullulan--and derivatized polysaccharides--methyl cellulose, hydroxypropyl cellulose, and carboxymethyl amylose sodium salt (CM-Am)--were investigated as chiral selectors in capillary electrophoresis. Effects of degree of polymerization and con... |
9228802 | Improved chiral separation using achiral modifiers in cyclodextrin modified capillary zone electrophoresis. | The influence of achiral modifiers on the chiral separation of propranolol is examined by cyclodextrin modified capillary zone electrophoresis. The improved chiral separation of propranolol is by molecules previously identified in our group as forming ternary complexes with cyclodextrin and pyrene. The polarity, chain ... |
9228736 | Thermodynamics of the hydrolysis and cyclization reactions of alpha-, beta-, and gamma-cyclodextrin. | A thermodynamic investigation of the hydrolysis and cyclization reactions of cyclomaltohexa-, hepta-, and octa-ose (alpha-, beta-, and gamma-cyclodextrins) has been performed using microcalorimetry and high-performance liquid-chromatography. The calorimetric measurements lead to standard molar enthalpy changes delta rH... |
9226595 | Use of 1H-NMR spectroscopy to determine the enantioselective mechanism of neutral and anionic cyclodextrins in capillary electrophoresis. | One-dimensional (ID) and two-dimensional (2D) 1H nuclear magnetic resonance (NMR) techniques have been used to investigate the chiral recognition process in capillary electrophoresis (CE) for seven different cyclodextrins (CDs) with the calcium channel blocker amlodipine as a model compound. These include five neutral ... |
9226554 | The influence of temperature on the multiple separation of estrogenic steroids using mobile phases modified with beta-cyclodextrin in high-performance liquid chromatography. | The effect of temperature on the retention and multiple separation of six estrogenic steroids in reversed-phase liquid chromatography has been studied. Capacity factors (k') of estriol, 17 beta-estradiol, 17 alpha-estradiol, d-equilenin, equilin and estrone were measured using mobile phase modified with different conce... |
9224933 | Accessibility of peptides displayed on filamentous bacteriophage virions: susceptibility to proteinases. | The genome of the filamentous bacteriophage fd has been engineered so that small peptides can be inserted into the exposed N-terminal segment of pVIII, the major protein of the virus capsid. Most small peptides can be displayed on all 2700 copies of pVIII (a recombinant virion), but larger peptides can be displayed onl... |
9223641 | Molecular recognition in the HIV-1 capsid/cyclophilin A complex. | The HIV-1 capsid protein (CA) makes an essential interaction with the human peptidyl prolyl isomerase, cyclophilin A (CypA), that results in packaging of CypA into the virion at a CA to CypA stoichiometry of approximately 10:1. The 231 amino acid residue capsid protein is composed of an amino-terminal CypA binding doma... |
9223630 | Recognition and manipulation of branched DNA structure by junction-resolving enzymes. | The junction-resolving enzymes are a class of nucleases that introduce paired cleavages into four-way DNA junctions. They are important in DNA recombination and repair, and are found throughout nature, from eubacteria and their bacteriophages through to higher eukaryotes and their viruses. These enzymes exhibit structu... |
9222501 | The selection in vivo and characterization of an RNA recognition motif for spectinomycin. | Ribonucleoprotein (RNP) complexes participate in almost all macromolecular processes, including RNA processing, protein synthesis, and the signal recognition of proteins targeted for export. An understanding of these processes requires detailed knowledge of interactions at the molecular level, which has evidently been ... |
9221895 | Enantioselective determination of 3,4-methylene-dioxymethamphetamine and two of its metabolites in human urine by cyclodextrin-modified capillary zone electrophoresis. | Using capillary zone electrophoresis with a phosphate buffer at pH 2.5 containing 30 mM (2-hydroxypropyl)-beta-cyclodextrin as chiral selector, the simultaneous separation of the enantiomers of 3,4-methylenedioxymethamphetamine (MDMA or Ecstasy) and its two metabolites 4-hydroxy-3-methoxymethamphetamine (HMMA) and 3,4-... |
9221894 | Enantioselective determination of methadone and its main metabolite 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP) in serum, urine and hair by capillary electrophoresis. | A capillary electrophoresis method has been developed for the enantioselective determination of methadone and its main metabolite 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP) in serum and urine. After addition of the internal standard diphenhydramine, the serum and urine samples were extracted at pH 9-10 wi... |
9221893 | Enantioseparation of local anaesthetic drugs by capillary zone electrophoresis with cyclodextrins as chiral selectors using a partial filling technique. | The enantiomers of prilocaine were successfully resolved with alpha-cyclodextrin, and those of mepivacaine and bupivacaine, with methyl-beta-cyclodextrin as chiral selectors, by means of capillary zone electrophoresis (CZE) employing a partial filling technique. By this separation mode, a discontinous separation zone i... |
9221892 | Enantioseparation of nonsteroidal anti-inflammatory drugs by capillary electrophoresis using mixtures of anionic and uncharged beta-cyclodextrins as chiral additives. | Nine nonsteroidal anti-inflammatory drugs (NSAIDs) were enantioseparated by capillary electrophoresis using an anionic cyclodextrin derivative (sulfobutyl ether beta-cyclodextrin or carboxymethyl-beta-cyclodextrin) in combination with a neutral cyclodextrin as chiral additives to a pH 3 phosphoric acid-triethanolamine ... |
9221891 | Enantiomer separation of denopamine by capillary electrophoresis with charged and uncharged cyclodextrins. | Direct separation of enantiomers of denopamine was investigated by capillary electrophoresis employing charged and uncharged cyclodextrin (CD) derivatives. Uncharged beta-type CDs, having hydrophobic groups, were essential for the enantioseparation of denopamine; of these, especially dimethyl-beta-CD was effective. Amo... |
9221890 | Enantiomer separation of disopyramide with capillary electrophoresis using various cyclodextrins. | Enantiomers of disopyramide display different biological actions, and therefore chiral selective analysis is necessary. Fifteen different cyclodextrins (CDs) and CD derivatives were tested as capillary electrophoresis (CE) additives for the chiral separation of disopyramide. Eleven types of CDs showed chiral recognitio... |
9221889 | Determination of the enantiomeric purity of N-propionyl-6,7-dimethoxy-2-aminotetralin by cyclodextrin-modified micellar electrokinetic chromatography. | N-Propionyl-6,7-dimethoxy-2-aminotetralin (Z12231A), a useful intermediate in the synthesis of dopaminergic agonists, was resolved into its enantiomers by high-performance capillary electrophoresis. Cyclodextrin-modified micellar electrokinetic chromatography was employed with a combination of chiral selectors both in ... |
9221888 | Resolution of acylated dipeptide stereoisomers by capillary electrophoresis using sulfobutylether derivatized beta-cyclodextrin. | The separation of enantiomerically and diastereomerically related stereoisomers of acylated Asp-Phe dipeptides was explored using capillary electrophoresis (CE). This series of dipeptides included the alpha-L,L parent compound and the three other potential Asp containing stereoisomers (alpha-D,D, alpha-L,D, and alpha-D... |
9221887 | Separation of synthesized enantiomers and diastereomers of thiino-[4,3-b]pyrrole-2,3-dione derivatives and 2H-thiopyrans by capillary electrophoresis. | Capillary electrophoresis was used to separate diastereomers and enantiomers of synthesized thiopyrans and thiinopyrroles. Separation conditions were optimized by varying the buffer parameters, i.e., kind and concentration of chiral selector, pH, main buffering component, micelle forming additives, and content of organ... |
9221884 | A quantitative relationship between capacity factor and selector concentration in capillary electrophoresis and high performance liquid chromatography: evidence from the enantioselective resolution of benzoin using human serum albumin as a chiral selector. | Many selectors are used both in pressure-driven liquid chromatography (LC) and in electrokinetic chromatography (EKC), particularly chiral species such as cyclodextrins and proteins. It should be possible to readily apply information gleaned using one technique to the other, since in both techniques the underlying mole... |
9221881 | Chiral interactions in capillary zone electrophoresis: computer simulation and comparison with experiment. | Chiral interaction in capillary electrophoresis can be modeled using pK values, mobilities of analytes, and their formation constants with the chiral selector. An existing steady-state simulation program for CE (HPCESIM) was recently extended with a chiral submenu involving the chiral parameters listed above. These wer... |
9221879 | Separation of enantiomers of drugs by capillary electrophoresis. Part 4: hydroxypropyl-gamma-cyclodextrin as chiral solvating agent. | In an extended chiral drug screening program, enantioseparation of 86 racemic drugs was tested with hydroxypropyl-gamma-cyclodextrin as chiral solvating agent (CSA). A total of 30 drugs out of 86 could be resolved in this straightforward approach. The number of experiments performed under identical conditions allows a ... |
9221878 | Determination of association constants of dansyl-amino acids and beta-cyclodextrin in N-methylformamide by capillary electrophoresis. | The use of nonaqueous background electrolytes in capillary electrophoresis (CE) is a promising new trend which should widen the scope of this technique. We demonstrate the chiral separation of dansyl-amino acids (Dns-AAs) in N-methylformamide (NMF) using beta-cyclodextrin (beta-CD) as chiral selector. The solubility of... |
9221876 | Histamine-modified beta-cyclodextrins for the enantiomeric separation of dansyl-amino acids in capillary electrophoresis. | Two novel monosubstituted beta-cyclodextrins (CD) bearing the histamine moiety linked to the upper CD rim, either through the amino group or the imidazole nitrogen 1N, CD-hm and CD-mh, were successfully used as chiral selectors in capillary electrophoresis for the enantiomeric discrimination of dansyl (Dns)-amino acids... |
9221875 | Electrokinetic chromatography employing an anionic and a cationic beta-cyclodextrin derivative. | beta-Cyclodextrin, 1, can act as a chiral buffer additive in capillary zone electrophoresis (CZE) owing to its ability to form diastereomeric complexes with the enantiomers of ionic compounds. Reaction of 1 with 2,3-epoxy-propyltrimethylammonium chloride gave preponderantly 6-O-(2-hydroxy-3-trimethylammoniopropyl) deri... |
9221874 | Use of a zwitterionic cyclodextrin as a chiral agent for the separation of enantiomers by capillary electrophoresis. | The purity and enantioselectivity of a novel chiral agent, the zwitterionic mono-(6-delta-glutamylamino-6-deoxy)-beta-cyclodextrin (beta-CD-Glu), were studied by capillary electrophoresis. Chiral separation of the enantiomers of chlorthalidone was obtained at pH 2.3, a pH at which beta-CD-Glu is partially protonated. C... |
9221873 | Three approaches to enantiomer separation of beta-adrenergic antagonists by capillary electrochromatography. | Three different capillary electrochromatographic methods for the enantiomer separation of beta-adrenergic antagonists (acebutolol, alprenolol, atenolol, metoprolol, pindolol, prenalterol, and propranolol) were applied using different cyclodextrins (beta-cyclodextrin, carboxymethyl-beta-cyclodextrin and dimethyl-beta-cy... |
9221872 | Capillary zone electrophoresis at subzero temperatures II: chiral separation of biogenic amines. | The separation of enantiomer pairs of eight biogenic amines by capillary zone electrophoresis (CZE) was investigated with heptakis (2,6-di-O-methyl)-beta-cyclodextrin as the chiral selector at temperatures ranging from -20 degrees to 40 degrees C by using a commercial electrophoresis unit retrofitted with an external t... |
9218799 | A role for the divergent actin gene, ACT2, in nuclear pore structure and function. | We have identified a temperature-sensitive allele of the yeast divergent actin gene ACT2, act2-1, which displays defects in nuclear pore complex (NPC) structure and nuclear import at the restrictive temperature. Although defective in nuclear import, act2-1 cells still selectively retain reporter proteins in the nucleus... |
9218788 | Tetramerization of the AKT1 plant potassium channel involves its C-terminal cytoplasmic domain. | All plant channels identified so far show high conservation throughout the polypeptide sequence except in the ankyrin domain which is present only in those closely related to AKT1. In this study, the architecture of the AKT1 protein has been investigated. AKT1 polypeptides expressed in the baculovirus/Sf9 cells system ... |
9218786 | CD66 carcinoembryonic antigens mediate interactions between Opa-expressing Neisseria gonorrhoeae and human polymorphonuclear phagocytes. | Colonization of urogenital tissues by the human pathogen Neisseria gonorrhoeae is characteristically associated with purulent exudates of polymorphonuclear phagocytes (PMNs) containing apparently viable bacteria. Distinct variant forms of the phase-variable opacity-associated (Opa) outer membrane proteins mediate the n... |
9218785 | Aerolysin and pertussis toxin share a common receptor-binding domain. | We have discovered that the bacterial toxins aerolysin and pertussis toxin share a common domain. This is surprising because the two toxins affect cells in very different ways. The common domain, which we call the APT domain, consists of two three-stranded antiparallel beta-sheets that come together and wrap around a c... |
9216088 | The toxicity of the Alzheimer's beta-amyloid peptide correlates with a distinct fiber morphology. | In an attempt to elucidate the relationship among aggregation properties, fiber morphology, and cellular toxicity several beta-amyloid peptides (A beta) were prepared according to a standardized procedure. Peptides either carried mutations inside the membrane anchor segment around amino acid position 35 or their carbox... |
9214621 | Dimer model for the microfibrillar protein fibulin-2 and identification of the connecting disulfide bridge. | Fibulin-2 is a novel extracellular matrix protein frequently found in close association with microfibrils containing either fibronectin or fibrillin. The entire protein and its predicted domains were obtained as recombinant products and examined by ultracentrifugation and electron microscopy. This demonstrated a disulf... |
9212805 | [Inoperable esophageal carcinoma managed by combined chemotherapy (CBDCA, 5-FU and VDS) and radiotherapy]. | Eleven inoperable patients with advanced esophageal carcinoma were treated with chemotherapy (carboplatin, 5-FU, vindesine) and concomitant radiotherapy. Two patients (T2) received this treatment due to their poor general condition and refusal of operation, and 9 patients for infiltration of tumor into the adjacent org... |
9204761 | Evolution of the multi-tubulin hypothesis. | Microtubules are organized into diverse cellular structures in multicellular organisms. How is such diversity generated? Although highly conserved overall, variable regions within alpha- and beta-tubulins show divergence from other alpha- and beta-tubulins in the same species, but show conservation among different spec... |
9202195 | Enzymic synthesis of 3'-O- and 6'-O-N-acetylglucosaminyl-N-acetyllactosaminide glycosides catalyzed by beta-N-acetyl-D-hexosaminidase from Nocardia orientalis. | beta-N-acetyl-D-hexosaminidase from Nocardia orientalis catalyzed the synthesis of beta-D-GlcNAc-(1 --> 3)-beta-D-Gal-(1 --> 4)-beta-D-GlcNAc-OC6H4NO2-p (1) and beta-D-GlcNAc-(1 --> 6)-beta-D-Gal-(1 --> 4)-beta-D-GlcNAc-OC6H4NO2-p (2) with its isomer beta-D-Gal-(1 --> 4)-[beta-D-GlcNAc-(1 --> 6)]-beta-D-GlcNAc-OC6H4NO2... |
9200704 | Function of conserved tryptophans in the Aspergillus niger glucoamylase 1 starch binding domain. | Nuclear magnetic resonance (NMR) and ultraviolet (UV) difference spectroscopy were used to assess the role of a number of tryptophan residues in the granular starch binding domain (SBD) of glucoamylase 1 from Aspergillus niger. Wild-type SBD and three variant (W563K, W590K, and W615K) proteins were produced using an A.... |
9197854 | Blood transfusion. An independent risk factor for postinjury multiple organ failure. | <h4>Objective</h4>To determine if blood transfusion is a consistent risk factor for postinjury multiple organ failure (MOF), independent of other shock indexes.<h4>Design</h4>A 55-month inception cohort study ending on August 30, 1995. Data characterizing postinjury MOF were prospectively collected. Multiple logistic r... |
9195917 | Domain analysis of the molecular recognition features of aromatic polyketide synthase subunits. | Bacterial aromatic polyketide synthases (PKSs) are a family of homologous multienzyme assemblies that catalyze the biosynthesis of numerous polyfunctional aromatic natural products. In the absence of direct insights into their structures, the use of gene fusions can be a powerful tool for understanding the structural b... |
9192632 | The abalone egg vitelline envelope receptor for sperm lysin is a giant multivalent molecule. | Abalone sperm lysin is a 16-kDa acrosomal protein, which nonenzymatically and species selectively creates a hole in the egg vitelline envelope (VE) through which the sperm passes to reach the egg cell membrane. The crystal structures of both monomeric and dimeric lysins have been solved and the sequences of lysins from... |
9192627 | Monomeric isomers of human interleukin 5 show that 1:1 receptor recruitment is sufficient for function. | The normally dimeric human interleukin 5 (IL-5) was re-engineered into two monomeric isomer forms to investigate mechanistic features of receptor recognition. One form, denoted GM1-IL-5, is a CD-loop expanded form, in which an 8-residue linker designed for flexibility was inserted between residues 85 and 86. The second... |
9192612 | Peptidyl-transferase inhibitors have antiviral properties by altering programmed -1 ribosomal frameshifting efficiencies: development of model systems. | The effects of two peptidyl-transferase inhibitors, anisomycin and sparsomycin, on ribosomal frameshifting efficiencies and the propagation of yeast double-stranded RNA viruses were examined. At sublethal doses in yeast cells these drugs specifically alter the efficiency of -1, but not of +1, ribosomal frameshifting. T... |
9194186 | The role of context on alpha-helix stabilization: host-guest analysis in a mixed background peptide model. | The helix content of a series of peptides containing single substitutions of the 20 natural amino acids in a new designed host sequence, succinyl-YSEEEEKAKKAXAEEAEKKKK-NH2, has been determined using CD spectroscopy. This host is related to one previously studied, in which triple amino acid substitutions were introduced... |
9194176 | Structural studies of the streptavidin binding loop. | The streptavidin-biotin complex provides the basis for many important biotechnological applications and is an interesting model system for studying high-affinity protein-ligand interactions. We report here crystallographic studies elucidating the conformation of the flexible binding loop of streptavidin (residues 45 to... |
9194175 | The uncharged surface features surrounding the active site of Escherichia coli DsbA are conserved and are implicated in peptide binding. | DsbA is a protein-folding catalyst from the periplasm of Escherichia coli that interacts with newly translocated polypeptide substrate and catalyzes the formation of disulfide bonds in these secreted proteins. The precise nature of the interaction between DsbA and unfolded substrate is not known. Here, we give a detail... |
9193706 | Coelenterazine analogs as chemiluminescent probe for superoxide anion. | Eleven new coelenterazine analogs containing the 3,7-dihydroimidazo[1,2-alpha]pyrazin-3-one structure were synthesized. The superoxide-triggered chemiluminescence of these compounds was investigated using the hypoxanthine-xanthine oxidase system in comparison with four known compounds. The results showed that an alkyl ... |
9192932 | Is outcome from ARDS related to the severity of respiratory failure? | The characteristics and outcome of acute respiratory distress syndrome (ARDS) may have changed with time. Some studies have reported that mortality is more commonly related to the development of sepsis/multiple organ failure (MOF), and others that it is related to the severity of acute respiratory failure (ARF). The pr... |
9191941 | Self-assembly of the JC virus major capsid protein, VP1, expressed in insect cells. | The major capsid protein of human polyomavirus JC virus, VP1, has been cloned into a baculovirus genome and expressed in insect cells. The VP1 protein was expressed in the cytoplasm and transported into the nucleus. It was then purified by a sucrose cushion and CsCI density gradient centrifugation to near homogeneity. ... |
9191848 | Specification of receptor-binding phenotypes of influenza virus isolates from different hosts using synthetic sialylglycopolymers: non-egg-adapted human H1 and H3 influenza A and influenza B viruses share a common high binding affinity for 6'-sialyl(N-acetyllactosamine). | Synthetic sialylglycoconjugates bearing 3'-sialyllactose, 6'-sialyllactose, or 6'-sialyl(N-acetyllactosamine) moieties attached to the polyacrylic acid carrier (P-3-SL, P-6-SL, and P-6-SLN, respectively) were prepared and tested for their ability to bind to influenza virus isolates from different hosts in a competitive... |
9191560 | Evaluation of two homogeneous methods for measuring high-density lipoprotein cholesterol. | We evaluated the performance of two homogeneous assays for quantifying HDL cholesterol (HDL-C) and compared them with the phosphotungstic acid (PTA)/ MgCl2 assay. Both homogeneous HDL-C assays were precise, having a within-run CV of < 1.20% and a between-run CV of < 4.07%. The HDL-C values (y) measured by the two homog... |
9190821 | Genetic analysis of second-site revertants of bacteriophage lambda integrase mutants. | Bacteriophage lambda site-specific recombination is catalyzed by the phage-encoded integrase (Int) protein. Using a collection of 21 recombination-defective Int mutants, we performed a second-site reversion analysis. One of the primary mutants contained a valine-to-glutamic acid change at position 175 (V175E), and a ps... |
9190808 | Vfr controls quorum sensing in Pseudomonas aeruginosa. | Pseudomonas aeruginosa controls several genes in a cell density-dependent manner through a phenomenon termed quorum sensing. The transcriptional activator protein of the las quorum-sensing system is encoded for by the lasR gene, which is at the top of a quorum-sensing hierarchy. The activation of LasR as a transcriptio... |
9190804 | Evidence that the N-terminal part of the S-layer protein from Bacillus stearothermophilus PV72/p2 recognizes a secondary cell wall polymer. | The S-layer of Bacillus stearothermophilus PV72/p2 shows oblique lattice symmetry and is composed of identical protein subunits with a molecular weight of 97,000. The isolated S-layer subunits could bind and recrystallize into the oblique lattice on native peptidoglycan-containing sacculi which consist of peptidoglycan... |
9188466 | Cyclodextrins are not the major cyclic alpha-1,4-glucans produced by the initial action of cyclodextrin glucanotransferase on amylose. | The initial action of cyclodextrin glucanotransferase (CGTase, EC 2.4.1.19) from an alkalophilic Bacillus sp. A2-5a on amylose was investigated. Synthetic amylose was incubated with purified CGTase then terminated in the very early stage of the enzyme reaction. When the reaction mixture was treated with glucoamylase an... |
9188684 | Residue accessibility, hydrogen bonding, and molecular recognition: metal-chelate probing of active site histidines in chymotrypsins. | Subspecies defining the maturation pathway of bovine chymotrypsinogen to alpha-chymotrypsin have been separated in a single chromatographic run by affinity to iminodiacetic acid-Cu(II) [IDA-Cu(II)] immobilized onto Novarose. A major highlight of the elution pattern is that, as maturation proceeds, these subspecies exhi... |
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