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10852846 | Development of the murine and human immune system: differential effects of immunotoxicants depend on time of exposure. | Fetal and early postnatal life represent critical periods in vertebrate immune system development. Disruption of such development by perinatal immunotoxic chemical exposure has been widely described in experimental animal models. The resultant inhibited postnatal immune responses in such animals are often more dramatic... |
10852708 | Human topoisomerase I poisoning by protoberberines: potential roles for both drug-DNA and drug-enzyme interactions. | Protoberberines represent a structural class of organic cations that induce topoisomerase I-mediated DNA cleavage, a behavior termed topoisomerase I poisoning. We have employed a broad range of biophysical, biochemical, and computer modeling techniques to characterize and cross-correlate the DNA-binding and topoisomera... |
10851412 | Lymph-node staining with activated carbon CH40: a new method for axillary lymph-node dissection in breast cancer. | <h4>Objective</h4>To demonstrate the usefulness of activated carbon particles (CH40) as a vital staining dye for visualizing lymphatic vessels and lymph nodes in breast cancer.<h4>Design</h4>A retrospective evaluation.<h4>Setting</h4>Department of Surgery in Sendai National Hospital, Japan, a 716-bed teaching hospital.... |
10851020 | Isoenzyme-specific interaction of muscle-type creatine kinase with the sarcomeric M-line is mediated by NH(2)-terminal lysine charge-clamps. | Creatine kinase (CK) is located in an isoenzyme-specific manner at subcellular sites of energy production and consumption. In muscle cells, the muscle-type CK isoform (MM-CK) specifically interacts with the sarcomeric M-line, while the highly homologous brain-type CK isoform (BB-CK) does not share this property. Sequen... |
10848961 | The role of individual lysine residues in the basic patch on turnip cytochrome f for electrostatic interactions with plastocyanin in vitro. | The role of electrostatic interactions in determining the rate of electron transfer between cytochrome f and plastocyanin has been examined in vitro with mutants of turnip cytochrome f and mutants of pea and spinach plastocyanins. Mutation of lysine residues Lys58, Lys65 and Lys187 of cytochrome f to neutral or acidic ... |
10848958 | The role of arginine 47 in the cyclization and coupling reactions of cyclodextrin glycosyltransferase from Bacillus circulans strain 251 implications for product inhibition and product specificity. | Cyclodextrin glycosyltransferase (CGTase) (EC 2.4.1.19) is used for the industrial production of cyclodextrins. Its application, however, is hampered by the limited cyclodextrin product specificity and the strong inhibitory effect of cyclodextrins on CGTase activity. Recent structural studies have identified Arg47 in t... |
10848957 | Recursive use of evolutionary conservation data in molecular modeling of membrane proteins A model of the multidrug H+ antiporter emrE. | Membrane proteins are currently the most biomedically important family of proteins, serving as targets for the majority of pharmaceutical agents. It is also clear that they are invariably abundant in all of the genomes sequence so far, representing up to a third of all open reading frames. Finally, and regrettably, it ... |
10848629 | Dynamic regulation of activated leukocyte cell adhesion molecule-mediated homotypic cell adhesion through the actin cytoskeleton. | Restricted expression of activated leukocyte cell adhesion molecule (ALCAM) by hematopoietic cells suggests an important role in the immune system and hematopoiesis. To get insight into the mechanisms that control ALCAM-mediated adhesion we have investigated homotypic ALCAM-ALCAM interactions. Here, we demonstrate that... |
10848627 | The MAL proteolipid is necessary for the overall apical delivery of membrane proteins in the polarized epithelial Madin-Darby canine kidney and fischer rat thyroid cell lines. | The MAL proteolipid has been recently demonstrated as being necessary for correct apical sorting of the transmembrane influenza virus hemagglutinin (HA) in Madin-Darby canine kidney (MDCK) cells. The fact that, in contrast to MDCK cells, Fischer rat thyroid (FRT) cells target the majority of glycosylphosphatidylinosito... |
10843617 | Synthesis and supramolecular characterization of a novel class of glycopyranosyl-containing amphiphiles. | A novel class of glycopeptidolipids is described, which potentially can be used as a novel antigen-delivery system. The compounds have been prepared by a combination of solid-supported and solution-based methods. The use of the orthogonally protected FmocLysDde derivative provided an opportunity to incorporate two diff... |
10841856 | Effects of market liberalisation on smoking in Japan. | <h4>Objective</h4>To document the effect of the liberalisation of the Japanese tobacco market on Japanese smoking rates and on Japanese tobacco industry practices.<h4>Data source</h4>Asahi Shimbun (major daily newspaper) from 1980 to 1996.<h4>Study selection</h4>Review of media coverage on the effects of market liberal... |
10841798 | Methanocarba analogues of purine nucleosides as potent and selective adenosine receptor agonists. | Adenosine receptor agonists have cardioprotective, cerebroprotective, and antiinflammatory properties. We report that a carbocyclic modification of the ribose moiety incorporating ring constraints is a general approach for the design of A(1) and A(3) receptor agonists having favorable pharmacodynamic properties. While ... |
10842084 | Expression of Crim1 during murine ocular development. | Crim1 (cysteine-rich motor neuron 1), a novel gene encoding a putative transmembrane protein, has recently been isolated and characterized (Kolle, G., Georgas, K., Holmes, G.P., Little, M.H., Yamada, T., 2000. CRIM1, a novel gene encoding a cysteine-rich repeat protein, is developmentally regulated and implicated in ve... |
10841778 | Denaturation of phosphofructokinase-1 from Saccharomyces cerevisiae by guanidinium chloride and reconstitution of the unfolded subunits to their catalytically active form. | Unfolding and refolding of heterooctameric phosphofructokinase-1 from Saccharomyces cerevisiae were investigated by application of kinetic, hydrodynamic, and spectroscopic methods and by use of guanidinium chloride (GdmCl) as denaturant. Inactivation of the enzyme starts at about 0.3 M GdmCl and undergoes a sharp unfol... |
10823899 | Amphetamine-induced loss of human dopamine transporter activity: an internalization-dependent and cocaine-sensitive mechanism. | The dopamine transporter (DAT) is a target of amphetamine (AMPH) and cocaine. These psychostimulants attenuate DAT clearance efficiency, thereby increasing synaptic dopamine (DA) levels. Re-uptake rate is determined by the number of functional transporters at the cell surface as well as by their turnover rate. Here, we... |
10829068 | Inhibition of huntingtin fibrillogenesis by specific antibodies and small molecules: implications for Huntington's disease therapy. | The accumulation of insoluble protein aggregates in intra and perinuclear inclusions is a hallmark of Huntington's disease (HD) and related glutamine-repeat disorders. A central question is whether protein aggregation plays a direct role in the pathogenesis of these neurodegenerative diseases. Here we show by using a f... |
10841570 | Extensive neurite outgrowth and active synapse formation on self-assembling peptide scaffolds. | A new type of self-assembling peptide (sapeptide) scaffolds that serve as substrates for neurite outgrowth and synapse formation is described. These peptide-based scaffolds are amenable to molecular design by using chemical or biotechnological syntheses. They can be tailored to a variety of applications. The sapeptide ... |
10841536 | Retrostructural analysis of metalloproteins: application to the design of a minimal model for diiron proteins. | De novo protein design provides an attractive approach for the construction of models to probe the features required for function of complex metalloproteins. The metal-binding sites of many metalloproteins lie between multiple elements of secondary structure, inviting a retrostructural approach to constructing minimal ... |
10841532 | Synthetic receptors as models for alkali metal cation-pi binding sites in proteins. | The alkali metal cations Na(+) and K(+) have several important physiological roles, including modulating enzyme activity. Recent work has suggested that alkali metal cations may be coordinated by pi systems, such as the aromatic amino acid side chains. The ability of K(+) to interact with an aromatic ring has been asse... |
10841518 | Antagonizing the parathyroid calcium receptor stimulates parathyroid hormone secretion and bone formation in osteopenic rats. | Parathyroid hormone (PTH) is an effective bone anabolic agent, but it must be administered parenterally. An orally active anabolic agent would provide a valuable alternative for treating osteoporosis. NPS 2143 is a novel, selective antagonist (a "calcilytic") of the parathyroid cell Ca(2+) receptor. Daily oral administ... |
10839822 | Acetylation of histones and transcription-related factors. | The state of chromatin (the packaging of DNA in eukaryotes) has long been recognized to have major effects on levels of gene expression, and numerous chromatin-altering strategies-including ATP-dependent remodeling and histone modification-are employed in the cell to bring about transcriptional regulation. Of these, hi... |
10839821 | Type I restriction systems: sophisticated molecular machines (a legacy of Bertani and Weigle). | Restriction enzymes are well known as reagents widely used by molecular biologists for genetic manipulation and analysis, but these reagents represent only one class (type II) of a wider range of enzymes that recognize specific nucleotide sequences in DNA molecules and detect the provenance of the DNA on the basis of s... |
10839820 | A functional-phylogenetic classification system for transmembrane solute transporters. | A comprehensive classification system for transmembrane molecular transporters has been developed and recently approved by the transport panel of the nomenclature committee of the International Union of Biochemistry and Molecular Biology. This system is based on (i) transporter class and subclass (mode of transport and... |
10839802 | Viral escape by selection of cytotoxic T cell-resistant variants in influenza A virus pneumonia. | Antigenic variation is a strategy exploited by influenza viruses to promote survival in the face of the host adaptive immune response and constitutes a major obstacle to efficient vaccine development. Thus, variation in the surface glycoproteins hemagglutinin and neuraminidase is reflected by changes in susceptibility ... |
10837495 | Dynamic interaction of plastocyanin with the cytochrome bf complex. | The interaction between plastocyanin and the intact cytochrome bf complex, both from spinach, has been studied by stopped-flow kinetics with mutant plastocyanin to elucidate the site of electron transfer and the docking regions of the molecule. Mutation of Tyr-83 to Arg or Leu provides no evidence for a second electron... |
10835396 | Histone acetylation and gene expression analysis of sex lethal mutants in Drosophila. | The evolution of sex determination mechanisms is often accompanied by reduction in dosage of genes on a whole chromosome. Under these circumstances, negatively acting regulatory genes would tend to double the expression of the genome, which produces compensation of the single-sex chromosome and increases autosomal gene... |
10835343 | Prohibitins act as a membrane-bound chaperone for the stabilization of mitochondrial proteins. | Prohibitins are ubiquitous, abundant and evolutionarily strongly conserved proteins that play a role in important cellular processes. Using blue native electrophoresis we have demonstrated that human prohibitin and Bap37 together form a large complex in the mitochondrial inner membrane. This complex is similar in size ... |
10835005 | Correlation between in vitro and in vivo antifungal activities in experimental fluconazole-resistant oropharyngeal and esophageal candidiasis. | Oropharyngeal and esophageal candidiasis (OPEC) is a frequent opportunistic mycosis in immunocompromised patients. Azole-resistant OPEC is a refractory form of this infection occurring particularly in human immunodeficiency virus (HIV)-infected patients. The procedures developed by the Antifungal Subcommittee of the Na... |
10828085 | alpha-cyclodextrin extracts diacylglycerol from insect high density lipoproteins. | alpha-Cyclodextrins are water-soluble cyclic hexamers of glucose units with hydrophobic cavities capable of solubilizing lipophiles. Incubating alpha-cyclodextrin with high density lipophorin from Manduca sexta or Bombyx mori resulted in a cloudy, turbid solution. Centrifugation separated a pale yellowish precipitate. ... |
10828004 | Direct characterization of the physicochemical properties of fungal spores using functionalized AFM probes. | A new method is described for characterizing the physicochemical properties of native microbial cells by using atomic force microscopy (AFM) with chemically functionalized probes. Adhesion forces were measured, under deionized water, between probes and model substrata functionalized with alkanethiol self-assembled mono... |
10827997 | Thermal denaturing of bacteriorhodopsin by X-Ray scattering from oriented purple membranes. | We present a temperature-dependent x-ray diffraction study of thin films of purple membranes (PMs) with the native membrane protein bacteriorhodopsin (BR). The high degree of alignment with respect to the silicon substrates allows for the application of modern interface-sensitive scattering techniques. Here we focus on... |
10827965 | Analysis of the composite response of shear wave resonators to the attachment of mammalian cells. | The suitability of the quartz crystal microbalance (QCM) technique for monitoring the attachment and spreading of mammalian cells has recently been established. Different cell species were shown to generate an individual response of the QCM when they make contact with the resonator surface. Little is known, however, ab... |
10825434 | Molecular dynamics study on lipid A from Escherichia coli: insights into its mechanism of biological action. | Structural properties of the Escherichia coli lipid A moiety were analysed by means of molecular mechanics and molecular dynamics simulations and compared to synthetic monophospho and dephospho analogues with different biological activities in the Limulus assay. The conformation of glucosamine disaccharide headgroup, o... |
10826109 | Interaction of antimalarial agent artemisinin with cyclodextrins. | To obtain an effective solution of the poorly water soluble antimalarial agent artemisinin, the use of several kinds of cyclodextrins (CDs) as solubilizers was examined. The following CDs were used in this study: alpha-CD, beta-CD, gamma-CD as parent CDs, 2-hydroxypropyl-beta-CD (HP-beta-CD), sulfobutyl ether beta-CD (... |
10825206 | A zinc finger transcription factor, alphaA-crystallin binding protein 1, is a negative regulator of the chondrocyte-specific enhancer of the alpha1(II) collagen gene. | Transcription of the type II collagen gene (Col2a1) is regulated by multiple cis-acting sites. The enhancer element, which is located in the first intron, is necessary for high-level and cartilage-specific expression of Col2a1. A mouse limb bud cDNA expression library was screened by the Saccharomyces cerevisiae one-hy... |
10823874 | Conserved surface-exposed K/R-X-K/R motifs and net positive charge on poxvirus complement control proteins serve as putative heparin binding sites and contribute to inhibition of molecular interactions with human endothelial cells: a novel mechanism for evasion of host defense. | Vaccinia virus complement control protein (VCP) has been shown to possess the ability to inhibit both classical and alternative complement pathway activation. The newly found ability of this protein to bind to heparin has been shown in previous studies to result in uptake by mast cells, possibly promoting tissue persis... |
10824992 | Modular retro-vectors for transgenic and therapeutic use. | Retroviruses have been used for many years as vectors for human gene therapy as well as for making transgenic animals. However, the efficient insertion of genes by retroviruses is often complicated by transcriptional inactivation of the retroviral long terminal repeats (LTRs) and by the production of replication-compet... |
10816532 | Interaction of Shigella flexneri IpaC with model membranes correlates with effects on cultured cells. | Invasion of enterocytes by Shigella flexneri requires the properly timed release of IpaB and IpaC at the host-pathogen interface; however, only IpaC has been found to possess quantifiable activities in vitro. We demonstrate here that when added to cultured cells, purified IpaC elicits cytoskeletal changes similar to th... |
10816509 | Receptor structure for F1C fimbriae of uropathogenic Escherichia coli. | F1C fimbriae are correlated with uropathogenic Escherichia coli strains. Although F1C fimbriae mediate binding to kidney tubular cells, their receptor is not known. In this paper, we demonstrate for the first time specific carbohydrate residues as receptor structure for F1C-fimbria-expressing E. coli. The binding of th... |
10816471 | Inhibition of staphylococcal enterotoxin B-induced lymphocyte proliferation and tumor necrosis factor alpha secretion by MAb5, an anti-toxic shock syndrome toxin 1 monoclonal antibody. | Toxic shock syndrome (TSS) is primarily caused by toxic shock syndrome toxin-1 (TSST-1) and staphylococcal enterotoxin B (SEB). These toxins belong to a family of pyrogenic toxin superantigens (PTSAgs) produced by Staphylococcus aureus and exhibit several shared biological properties, including the induction of massive... |
10816441 | Expression and protein-binding studies of the EEN gene family, new interacting partners for dynamin, synaptojanin and huntingtin proteins. | EEN, identified initially as a fusion partner to the mixed-lineage leukaemia gene in human leukaemia, and its related members, EEN-B1 and EEN-B2, have recently been shown to interact with two endocytic molecules, dynamin and synaptojanin, as well as with the huntingtin protein. In the present study, we show that the ex... |
10816423 | Cholesterol decreases secretion of the secreted form of amyloid precursor protein by interfering with glycosylation in the protein secretory pathway. | Cerebral deposits of beta-amyloid (betaA) are a major feature in Alzheimer's disease. betaA is derived from amyloid precursor protein (APP). APP is subject to N- and O-glycosylation and undergoes a series of proteolytic cleavages that lead to the release of betaA or of a non-amyloidogenic secreted form of APP (APPs). W... |
10817725 | vanC cluster of vancomycin-resistant Enterococcus gallinarum BM4174. | Glycopeptide-resistant enterococci of the VanC type synthesize UDP-muramyl-pentapeptide[D-Ser] for cell wall assembly and prevent synthesis of peptidoglycan precursors ending in D-Ala. The vanC cluster of Enterococcus gallinarum BM4174 consists of five genes: vanC-1, vanXY(C), vanT, vanR(C), and vanS(C). Three genes ar... |
10817719 | Comparison of nikkomycin Z with amphotericin B and itraconazole for treatment of histoplasmosis in a murine model. | Nikkomycin Z was tested both in vitro and in vivo for efficacy against Histoplasma capsulatum. Twenty clinical isolates were tested for susceptibility to nikkomycin Z in comparison to amphotericin B and itraconazole. The median MIC was 8 microg/ml with a range of 4 to 64 microg/ml for nikkomycin Z, 0.56 microg/ml with ... |
10817694 | Antifungal activity of amphotericin B cochleates against Candida albicans infection in a mouse model. | Cochleates are lipid-based supramolecular assemblies composed of natural products, negatively charged phospholipid, and a divalent cation. Cochleates can encapsulate amphotericin B (AmB), an important antifungal drug. AmB cochleates (CAMB) have a unique shape and the ability to target AmB to fungi. The minimal inhibito... |
10814586 | Hydrolytic action of alpha-amylase on high-amylose starch of low molecular mass. | High-amylose starches of low average degree of polymerization (d-p 61-71), formed as fine granules by interaction of Bacillus macerans cyclodextrin glucanotransferase with alpha-cyclodextrin (CD) at 2-70 degrees C, are highly insoluble in water and not gelatinizable under normal cooking conditions (100 degrees C). Samp... |
10813823 | Do more complex organisms have a greater proportion of membrane proteins in their genomes? | One may speculate that higher organisms require a proportionately greater abundance of membrane proteins within their genomes in order to furnish the requirements of differentiated cell types, compartmentalization, and intercellular signalling. With the recent availability of several complete prokaryotic genome sequenc... |
10815720 | Fluorescence determination of sulphobutylether-beta-cyclodextrin in human plasma by size exclusion chromatography with inclusion complex formation. | A selective method for the determination of sulphobutylether-beta-cyclodextrin (SBECD) in human plasma has been developed and validated over the range 4-200 microg ml(-1). SBECD is extracted from plasma using end-capped cyclohexyl solid phase extraction cartridges. This is followed by high performance size exclusion ch... |
10809676 | Identification of an effector specificity subregion within the aromatic-responsive regulators DmpR and XylR by DNA shuffling. | The Pseudomonas derived sigma(54)-dependent regulators DmpR and XylR control the expression of genes involved in catabolism of aromatic compounds. Binding to distinct, nonoverlapping groups of aromatic effectors controls the activities of these transcriptional activators. Previous work has derived a common mechanistic ... |
10799616 | Structure-function studies of the self-assembly domain of the human immunodeficiency virus type 1 transmembrane protein gp41. | The coiled-coil region of the human immunodeficiency virus type 1 transmembrane protein (gp41) makes up the interior core of the six-helix bundle structure of the gp41 self-assembly domain. We extended our previous study of this domain (Y. Weng and C. D. Weiss, J. Virol. 72:9676-9682, 1998) by analyzing 23 additional m... |
10799596 | Influenza A viruses lacking sialidase activity can undergo multiple cycles of replication in cell culture, eggs, or mice. | Influenza A viruses possess both hemagglutinin (HA), which is responsible for binding to the terminal sialic acid of sialyloligosaccharides on the cell surface, and neuraminidase (NA), which contains sialidase activity that removes sialic acid from sialyloligosaccharides. Interplay between HA receptor-binding and NA re... |
10799567 | Functional analyses of the EBNA1 origin DNA binding protein of Epstein-Barr virus. | The EBNA1 protein of Epstein-Barr virus (EBV) governs the replication and segregation of the viral episomes in latently infected cells and transactivates the expression of other EBV latency proteins through direct interactions with DNA sequences in the EBV latent origin of replication, oriP. To better understand how EB... |
10789986 | Guest dechlorination and covalent capture following photoexcitation of inclusion complexes in water. | Photoexcitation of complexes between cyclophane 1 and 1- or 2-chloronaphthalene in aqueous solution leads to rapid dechlorination of the guest, a reaction driven by electron transfer from host to excited guest. The main photoproducts contain a naphthyl group covalently attached to the host framework. The results may le... |
10789982 | Solubilization of substituted indole compounds by beta-cyclodextrin in water. | The solubilization of four pairs of substituted indole compounds (SICs) by beta-cyclodextrin (beta-CD) in water was investigated. The results show that 1,2,3,4-tetrahydrocarbazole and N-methyl-1,2,3,4-tetrahydrocarbazole form 1:1 inclusion complexes with beta-CD, while the other six SICs form 1:2 inclusion complexes, r... |
10934352 | Scanning Near-Field Optical Microscopy and Spectroscopy as a Tool for Chemical Analysis. | Research into the nanometer-scale region is currently of relevance in many branches of modern science and engineering, such as in microelectronics, supramolecular chemistry, and in a biological context. A great deal of attention is given to the design of molecular devices, usually towards understanding the function of ... |
10850791 | Modeling of ion complexation and extraction using substructural molecular fragments | A substructural molecular fragment (SMF) method has been developed to model the relationships between the structure of organic molecules and their thermodynamic parameters of complexation or extraction. The method is based on the splitting of a molecule into fragments, and on calculations of their contributions to a gi... |
10845629 | Molecular spin ladders | The structural and magnetic characteristics of the recently discovered quantum spin ladders are summarised and the possibilities of supramolecular chemistry for developing such fascinating materials are discussed. The existing examples of molecular spin ladders clearly show that typical supramolecular and crystal engin... |
10839186 | Naked Au55 clusters: dramatic effect of a thiol-terminated dendrimer | Reaction of the thiol-terminated fourth-generation dendrimer 2-G4 (96 SH groups) with the gold cluster compound Au55(PPh3)12Cl6 in a 3:1 molar ratio in dichloromethane results in the formation of bare Au55 clusters. The cuboctahedrally shaped Au55 particles coalesce to well-formed microcrystals (Au55) infinity. The rol... |
10839184 | [1]rotaxanes and pretzelanes: synthesis, chirality, and absolute configuration [In Process Citation] | The synthesis of aliphatically bridged [1](n)rotaxanes and (n)pretzelanes in preparative yields and the dependency of their chiroptical properties on the length (n) of their bridge are reported. A cycloenantiomeric bis(sulphonamide)[2]rotaxane with a sulphonamide group in its axle and its wheel was intramolecularly dia... |
10830957 | Intercalation of alkylamines into an organic polymer crystal | Organic solid-state synthesis allows formation of products that are difficult or impossible to produce by conventional methods. This feature, and the high degree of reaction selectivity that can be achieved, is a direct result of the control over the relative orientation of the reactants afforded by the solid state. Bu... |
10823931 | A route to hierarchical materials based on complexes of metallosupramolecular polyelectrolytes and amphiphiles. | Anisotropic thin film materials of metallosupramolecular polyelectrolyte-amphiphile complexes (denoted PACs) with structures at several length scales were fabricated through a multistep self-assembly process. Metal ion-mediated self-assembly of the ditopic ligand 1,4-bis(2,2':6',2"-terpyridine-4'-yl)benzene and electro... |
10814466 | The effect of varying substituents on the equilibrium distribution and conformation of macrocyclic steroidal N-acyl hydrazones | The equilibrium distribution of deoxycholate-based macrocyclic N-acyl hydrazones is dependent upon the nature of the substituents at the 3- and 12-position. These substituents can also influence the preferred conformation of the macrocycles. The conversion of pure cyclic dimer and trimer into a mixture of both componen... |
10814445 | A cyclodextrin-based molecular shuttle containing energetically favored and disfavored portions in its dumbbell component | A molecular shuttle containing dodecamethylene units, 4, 4'-bipyridinium units, and alpha-cyclodextrin (alpha-CD) has been prepared. Shuttling behavior is solvent- and temperature-sensitive and could be controlled by double interactions: hydrophobic interaction between a CD ring and a station and a repulsive interactio... |
10814172 | Molecular design of crown ethers. 19.(1) synthesis of novel disulfide- and diselenide-bridged Bis(benzo-12-crown-4)s and their Ag(+)-selective electrode properties | Two novel heteroatom-bridged bis(benzo-12-crown-4 ether)s, i.e., bis(2-nitro-4,5-(1,4,7,10-tetraoxadecamethylene)phenyl) disulfide (4) and diselenide (5), have been synthesized and characterized by elemental analysis and mass, IR, UV, and (1)H NMR spectroscopy. An X-ray crystallographic structure was obtained for 4. Io... |
10810712 | An extremely stable interwoven supramolecular bundle | [formula: see text] A tritopic receptor, in which three benzo[24]crown-8 macrorings are fused onto a triphenylene core, forms very strong supramolecular bundle-like complexes in CDCl3/CD3CN solution with trifurcated trications wherein three dibenzylammonium ions are linked to a central benzenoid core. The triply thread... |
10808447 | Enantioselective photocyclization of amides to beta-lactam derivatives in inclusion crystals with an optically active host | Irradiation of inclusion crystals of 2-(N-acyl-N-alkylamino)cyclohex-2-enones and N,N-dimethylphenylglyoxylamide with chiral host molecules gave the optically active N-alkyl-1-azaspiro[3.5]-nonane-2,5-diones and 3-hydroxy-1-methyl-3-phenylazetidin-2-one, respectively. The crystal structure of the 1:1 inclusion complex ... |
10808446 | EPR properties of two new cyclic phosphinylhydrazyl radicals and of their inclusion complexes with cyclodextrins | Two phosphorus-containing hydrazines, namely morpholin-4-ylphosphoramidic acid diethyl ester (1a) and (2,2,6,6-tetramethylpiperidin-1-yl)phosphoramidic acid diethyl ester (2a), have been synthesized. The corresponding hydrazyl radicals (1b and 2b) have been obtained, by in situ oxidation, and their properties have been... |
10808432 | Selectively monomodified cyclodextrins. Synthetic strategies | Monomodifications of cyclodextrins to give selectively 2-, 3-, or 6-substituted product is a challenging task because of the number of hydroxyl groups that can potentially react with the incoming reagent. The principles and the methods involved in manipulations of the differences in the chemistry of these hydroxyl grou... |
10793202 | Review: cyclodextrins and their interaction with amylolytic enzymes. | This review is concerned with inhibition of amylases by cyclodextrins (cyclic maltooligosaccharides), the interaction that occurs between amylases and cyclodextrins and the application of cyclodextrin affinity chromatography in the purification of amylases. In many cases, amylases that are competitively inhibited by cy... |
11254265 | Structures of Fibrous Supramolecular Assemblies Constructed by Amino Acid Surfactants: Investigation by AFM, SANS, and SAXS. | Aqueous gel-like solutions of N-acyl-L-aspartic acids (C(n)Asp, n=14, 16, 18) and N-dodecanoyl-beta-alanine (C(12)Ala) were prepared at pH 5-6 at room temperature. Structures of supramolecular assemblies in the solutions were investigated by atomic force microscopy (AFM), small-angle neutron scattering (SANS), and smal... |
12541565 | [Study on mixed stationary phase composed of 2,3,6-tributyl-beta-cyclodextrin and AgNO3 for capillary gas chromatography]. | A new mixed gas chromatographic stationary phase composed of 2,3,6-tributyl-beta-cyclodextrin and AgNO3(in polyethylene glycol 400) was synthesized for the first time. It was coated on fused silica capillary column. Excellent selectivity was obtained for the separation of seven enantiomeric pairs and four groups of pos... |
12541559 | [Preparation and evaluation of glycine derivatized beta-cyclodextrin bonded silica for high performance liquid chromatography]. | Glycine derivatized beta-cyclodextrin bonded silica (GCDS) has been prepared for high performance liquid chromatography through the reactions of beta-cyclodextrin bonded silica with tosyl chloride and glycine in sequence. The separation performance of GCDS for positional isomers, dansyl amino acids and phenylpropionic ... |
12526528 | Polyamine macrocycles incorporating a phenolic function: their synthesis, basicity, and coordination behavior toward metal cations. Crystal structure of a binuclear nickel complex. | The synthesis and characterization of two new polyazamacrocycles, 1,4,7,10-tetraaza[12](2,6)phenolphane (L1) and 1,4,7,10,13-pentaaza[15](2,6)phenolphane (L2), are reported. Both ligands incorporate the 2,6-phenolic unit within the cyclic framework. The basicity behavior and the ligational properties of L1 and L2 towar... |
12526509 | Calix[4]arenes as selective extracting agents. An NMR dynamic and conformational investigation of the lanthanide(III) and thorium(IV) complexes. | The lanthanide and Th4+ complexes with calix[4]arene ligands substituted either on the narrow or at the wide rim by four coordinating groups behave totally differently as shown by an NMR investigation of the dia- and paramagnetic complexes. Solutions of complexes were prepared by reacting anhydrous metal perchlorate sa... |
12526507 | Structurally reinforced tetraazamacrocyclic complexes. | The reaction between alkyl or aryl aldehydes and macrocyclic ligands with pendant amine groups produced imidazolidine-containing bi- or tricyclic ligands. The copper complexes of three of these ligands were structurally characterized: [CuL3Cl].3H2O (triclinic, P1, a = 10.041(2) A, b = 10.172(1) A, c = 11.202(1) A, alph... |
12526498 | Synthesis and characterization of the dimethyl-substituted bisbenzimidazole ligand and its manganese complex. | Macrocycles with unique properties provide new avenues for the design of novel catalysts and materials. Here, we report, for the first time, the synthesis and characterization of the dimethyl-substituted bisbenzimidazole ligand (Me2BBZ) and its manganese complex (Mn-Me2BBZ). The Me2BBZ ligand is similar to porphyrin an... |
12526483 | Programming the assembly of two- and three-dimensional architectures with DNA and nanoscale inorganic building blocks. | The use of biochemical molecular recognition principles for the assembly of nanoscale inorganic building blocks into macroscopic functional materials constitutes a new frontier in science. This article details efforts pertaining to the use of sequence-specific DNA hybridization events and novel inorganic surface coordi... |
11828620 | Dextrin as excipient in pharmaceutical preparations. | The addition of commercial dextrins to aqueous solvents in thin layer chromatography on cellulose increases the Rf values of azodyes such as methyl orange. The increase is less than with cyclodextrins but shows that dextrins also form supramolecular complexes. This should be considered when dextrins are used as "inert"... |
11428118 | Spin-state variation in solid state and solution of mononuclear iron(II) 1,4,7-trimethyl-1,4,7-triazacyclonane complexes. | The series of mononuclear iron(II) complexes with the tridentate macrocycle Me3tacn have been prepared (Me3tacn = 1,4,7-trimethyl-1,4,7-triazacyclonane). A purple, spin-crossover complex [Fe(Me3tacn)(MeCN)3](CF3-SO3)2 (1-OTf) forms in acetonitrile but readily loses MeCN ligands to form a colorless high-spin complex Fe(... |
11225873 | Separation of trace amounts of palladium (II) with crown ether from hydrochloric acid and potassium thiocyanate media. | A new method for the separation of trace amounts of palladium from hydrochloric acid and potassium thiocyanate media has been established based on the formation of an ion-pair complex of palladium thiocyanate anion Pd(SCN)4(2-) and the cationic potassium complex of dicyclohexyl- 18-crown-6 (DC18C6) in chloroform. The e... |
11225870 | Calixarenes in analytical and separation chemistry. | Discovered in the 1940's, [1n]metacyclophanes with the common name calix[n]arenes which is derived from for the molecule's shape enjoyed a remarkable interest in almost all fields of chemistry since the 1980's, which is highlighted by several books [1-8]. Over 50 reviews concerning their synthesis, properties and appli... |
10994035 | Flutamide-hydroxypropy-beta-chiyclodextrin complex: formulation, physical characterization, and absorption studies using the Caco-2 in vitro model. | <h4>Purpose</h4>The objective of this research was to formulate flutamide (FLT) in hydroxypropyl-beta-cyclodextrin (HPbetaCyD), and to investigate FLT transcellular permeation from the complex using the Caco-2 monolayer in vitro model.<h4>Methods</h4>Classical solubility data were used to derive thermodynamic parameter... |
10961291 | Natural antibodies and the host immune responses to xenografts. | Natural antibodies are present in the serum of individuals in the absence of known antigenic stimulation. These antibodies are primarily IgM, polyreactive, and encoded by immunoglobulin V genes in germline configuration. Natural antibodies are produced by B-1 lymphocytes, cells that form the primary cell of the fetal a... |
10952019 | A repression-derepression mechanism regulating the transcription of human immunodeficiency virus type 1 in primary T cells. | <h4>Background</h4>Despite some controversy regarding the preferential infection and replication of human immunodeficiency virus type 1 (HIV-1), it appears that primary T lymphocytes, in their quiescent state, are nonpermissive for viral expression and propagation. Massive activation of viral gene expression occurs onl... |
10949378 | Phytobilin biosynthesis: the Synechocystis sp. PCC 6803 heme oxygenase-encoding ho1 gene complements a phytochrome-deficient Arabidopsis thalianna hy1 mutant. | The phytobilin chromophores of phycobiliproteins and phytochromes are biosynthesized from heme in a pathway that begins with the opening of the tetrapyrrole macrocycle of protoheme to form biliverdin IXalpha, in a reaction catalyzed by heme oxygenase. An Arabidopsis thaliana hy1 mutant was previously shown to be defici... |
10927914 | Approaches to reducing toxicity of parenteral anticancer drug formulations using cyclodextrins. | Mitomycin C (MMC) is a clinically useful anticancer drug which can cause severe dermatological problems upon injection. It can cause delayed erythema and/or ulceration occurring either at or distant from the injection site for weeks or even months after administration. In an attempt to reduce the skin necrosis, complex... |
10914423 | The ultrastructural and histophotometric study of elastic and collagen fibers in type II Ehlers-Danlos syndrome and subclinical forms. | Skin disorders in type II Ehlers-Danlos Syndrome (EDS) are characterized by signs of cutaneous hyperdistensibility, skin and vascular fragility, atrophic scars, and articular hypermobility. These features may have less important clinical presentation in the intermediate forms of type II EDS. The authors studied the ult... |
10900722 | [The concept of the development of multiple organ failure in a model of gestosis]. | Mechanisms of development of multiple organ failure (MOF) in gestosis have been studied. Analysis of the findings of examinations of 95 women with gestosis hospitalized in intensive care wards of Institute for Maternity and Neonatality Protection demonstrated that elements of the systemic inflammatory response syndrome... |
10892344 | Recent insights on RNA folding mechanisms from catalytic RNA. | Methods for probing RNA structure in real time have revealed that initial folding steps are complete in less than a second. Refolding of large catalytic RNAs in vitro often results in long-lived intermediates that reach the native structure very slowly. These kinetically trapped intermediates arise from alternative sec... |
10893037 | Analysis of polymyxin B sulfate by capillary zone electrophoresis with cyclodextrin as additive. Method development and validation. | A capillary zone electrophoresis method for analysis of polymyxin B sulfate is described. In this method, triethanolamine (TEA)-phosphate buffer at pH 2.5 was employed to reduce the adsorption of analyte onto the capillary wall. Methyl-beta-cyclodextrin (M-beta-CD) and 2-propanol (IPA) were found to be necessary for se... |
10893027 | Direct liquid chromatographic enantiomer separation of new fluoroquinolones including gemifloxacin. | The enantiomers of gemifloxacin mesylate (formerly LB20304a), a new fluoroquinolone compound with potent in vitro and in vivo antibacterial profile were resolved on a commercially available Crownpak CR chiral stationary phase (CSP). All of the fluoroquinolones, including gemifloxacin used in this study, were well enant... |
10886365 | A novel RNA motif that binds efficiently and specifically to the Ttat protein of HIV and inhibits the trans-activation by Tat of transcription in vitro and in vivo. | <h4>Background</h4>To find a novel RNA that would bind efficiently and specifically to Tat protein but not to other cellular factors, we used an in vitro selection method and isolated a novel aptamer RNATat, a 37-mer RNA oligomer, that binds efficiently to the Tat protein of HIV-1. In the present study, we analysed var... |
10886361 | Thermodynamic and kinetic analyses for understanding sequence-specific DNA recognition. | Thermodynamic and kinetic analyses of biomolecular interactions reveal details of the energetic and dynamic features of molecular recognition processes, and complement structural analyses of the free and complexed conformations. The recent improvements in both isothermal titration calorimetry and surface plasmon resona... |
10883363 | [Inflammation and immunoparalysis. What are the differential criteria?]. | Multiple organ failure (MOF) may occur early or late after trauma. Besides direct physical injury of organs, compromise of the microcirculation by inflammation plays an important role in the pathogenesis of MOF. Inflammation also induces counterregulatory responses which may end up in immunoparalysis. As a result, infe... |
10883361 | [Protection of the mucosal barrier by nutritional strategies. What are the therapeutic options?]. | The dysfunction of intestinal barrier allows the translocation of both endotoxin and whole bacterial organisms. It plays an important role in the development of multiple organ failure (MOF). The mucosa ia one component of this barrier. Trauma, atrophy and the "systemic inflammatory response syndrome" increase gastroint... |
10872592 | Determination of enantiomeric amphetamines as metabolites of illicit amphetamines and selegiline in urine by capillary electrophoresis using modified beta-cyclodextrin. | The determination of enantiomeric amphetamine and methamphetamine in urine samples is important in order to distinguish use of the prescription drug selegiline (metabolized to R(-)-A and R(-)-MA) from the illicit use of S(+)-A and S(+)-MA. For the analysis of enantiomeric amphetamine (A) and methamphetamine (MA) in bio... |
10872569 | Determination of enantiomeric metabolites of l-deprenyl, d-methamphetamine, and racemic methamphetamine in urine by capillary electrophoresis: comparison of deprenyl use and methamphetamine use. | The enantiomeric analysis of urine collected from rats administered l-deprenyl, d-methamphetamine (MA), or dl-MA and from healthy male volunteers who ingested l-deprenyl by capillary electrophoresis (CE) using carboxy methylated-beta-cyclodextrin (CMCD) as a chiral selector was investigated to compare the metabolic pat... |
10867711 | Quantitative and sequence-specific analysis of DNA-ligand interaction by means of fluorescent intercalator probes. | A novel method of analysis of double-stranded DNA-ligand interaction is presented. The interaction is monitored by the fluorescence of a DNA bis-intercalator oxazole homodimer YoYo-3. The fluorescence intensity or its decay time reflects the modification of the DNA double helix. The DNA sequence is scanned by hybridiza... |
10867710 | Ionization state and molecular docking studies for the macrophage migration inhibitory factor: the role of lysine 32 in the catalytic mechanism. | The macrophage migration inhibitory factor (MIF) is a cytokine that is structurally similar to certain isomerases and for which multiple immune and catalytic roles have been proposed. Different catalytic activities have been reported for MIF, yet the exact mechanism by which MIF acts is not completely known. As a tauto... |
10867709 | Practical considerations in BIA/MS: optimizing the biosensor-mass spectrometry interface. | Biomolecular interaction analysis mass spectrometry (BIA/MS) is a multiplexed analytical technique that utilizes a unique combination of surface plasmon resonance (SPR) and matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) for the detection and analysis of small amounts of prot... |
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