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29711135 | Metalloporphyrin Dendrimers with Folding Arms. | Rigid and flexible linkers are combined in the new dendrimer shown schematically in the picture, which contains nine metalloporphyrin units (Porph). The construction is such that the four "arms" of the dendrimer can fold in a cooperative and predetermined manner in response to added 1,4-diazabicyclo[2.2.2]octane (DABCO... |
29711121 | A New Motif for the Self-Assembly of [2]Pseudorotaxanes; 1,2-Bis(pyridinium)ethane Axles and [24]Crown-8 Ether Wheels. | Multiple intramolecular interactions help to stabilize the novel [2]pseudorotaxanes formed from 1,2-bis(pyridinium)ethane dications (which act as axles) and 24-membered crown ethers (which act as wheels; see structure). This is the first successful sythesis of [2]pseudorotaxanes with [24]crown-8 as the macrocycle. |
29711117 | Polyvalent Interactions in Biological Systems: Implications for Design and Use of Multivalent Ligands and Inhibitors. | Found throughout biology, polyvalent interactions are characterized by the simultaneous binding of multiple ligands on one biological entity to multiple receptors on another (top part of the illustration) and have a number of characteristics that monovalent interactions do not (bottom). In particular, polyvalent intera... |
29711116 | Strategies for the Dynamic Integration of Combinatorial Synthesis and Screening. | Selection and amplification of only those components with the desired property-the integration of combinatorial chemistry and screening makes this possible. If the components of a combinatorial library are in a reversible equilibrium, the desired components can be selected and amplified by shifting the equilibrium of t... |
29711103 | Directed Positioning of Organometallic Fragments Inside a Calix[4]arene Cavity. | A hemispherical diphosphane based on a calixarene allows encapsulation of reactive M-R fragments (M=transition metal; R=H, alkyl, CO) inside the calixarene cavity. The ruthenium complex 1 has an unprecedented sandwich structure that contains a CO ligand confined between two phosphane-substituted phenyl rings. The separ... |
29711102 | PNA: Synthetic Polyamide Nucleic Acids with Unusual Binding Properties. | The astonishing discovery that peptide nucleic acids (PNAs, B=nucleobase), in spite of their drastic structural difference to natural DNA, are better nucleic acid mimetics than many other oligonucleotides has resulted in an explosion of research into this class of compounds. The synthesis, physical properties, and biol... |
29711096 | Metallosupramolecular Thin Polyelectrolyte Films. | Molecular recognition and electrostatic interaction of oppositely charged polyelectrolytes are combined in the fabrication of ultrathin metallosupramolecular multilayers [shown schematically in the picture, PEI=polyethyleneimine, PSS=poly(styrene sulfonate)]. The layers between the PSS layers are composed of an iron(II... |
18967404 | Practice and mechanism of HPLC oligosaccharide separation with a cyclodextrin bonded phase. | A series of six oligosaccharides: linear arabinosides, cellosides, isomaltosides, mannosides, maltosides and xylosides containing up to 15 sugar units, as well as alpha, beta and gamma-cyclodextrins, were separated without derivatization with acetonitrile-water mobile phases and a beta-cyclodextrin bonded phase column ... |
9812891 | Ultrastable mesostructured silica vesicles | A family of mesoporous molecular sieves (denoted MSU-G) with vesiclelike hierarchical structures and unprecedented thermal (1000 degreesC) and hydrothermal stabilities (more than 150 hours at 100 degreesC) associated with high SiO4 cross-linking was prepared through a supramolecular assembly pathway that relies on hydr... |
9797294 | Identification of a marine agarolytic pseudoalteromonas isolate and characterization of its extracellular agarase | The phenotypic and agarolytic features of an unidentified marine bacteria that was isolated from the southern Pacific coast was investigated. The strain was gram negative, obligately aerobic, and polarly flagellated. On the basis of several phenotypic characters and a phylogenetic analysis of the genes coding for the 1... |
11670741 | The Intra- and Intermolecular Oxidative Coupling of Ni(II)-meso-Octaethyl Mono(pyridine)-Tris(pyrrole) Complex Leading to C-C Bonds: Pathways to Oligomeric Porphyrinogens. | This paper reports the oxidative transformations of the unprecedented meso-octaalkyl mono(pyridine)-tris(pyrrole) macrocycle [Et(8)(C(5)H(3)N)(C(4)H(2)NH)(3)], 1, which was obtained by a homologation of the corresponding porphyrinogen, [Et(8)(C(4)H(2)NH)(4)], A. The metallation of 1 was obtained via its deprotonation w... |
10873299 | Steroid hormone (hydrocortisone, oestradiol and testosterone) uptake, storage or induced synthesis in tetrahymena. | After cyclodextrin-coated 10(-6) m steroid hormone treatment for 3 days (hormonal imprinting), Tetrahymena cells and their media were analysed by radioimmunoassay for the same hormone and for the presence of the other two. In the absence of hormone treatment, the cells contained no detectable levels of the three steroi... |
12016948 | [Studies on the pharmacokinetic-pharmacodynamic model of ketoprofen beta-CD inclusion complex in rabbits]. | A simple HPLC-UV method was established to determine concentrations of ketoprofen (KP) in rabbit plasma following oral administration. Twelve rabbits were selected and divided into three groups. KP beta-CD inclusion complex suspension, KP entity suspension (in 0.5% CMC-Na) and 0.5% CMC-Na suspension (as a placebo group... |
11938910 | [A study on the binding of cyclodextrins with terbutaline enantiomers by chiral capilary zone electrophoresis]. | The recognition mechanism of enantioselectivity in cyclodextrin-modified capillary zone electrophoresis (CD-CZE) on a racemic basic drug terbutaline was discussed. The equilibrium constants of host-guest complexation of terbutaline enantiomers with alpha-cyclodextrin, beta-cyclodextrin, 2,6-dimethyl-beta-cycoldextrin, ... |
10193325 | Intraepithelial haemorrhage of the oesophagus: a terminal event in haematological disorders. | <h4>Aims</h4>To investigate the clinicopathological findings in cases with intraepithelial haemorrhage of the oesophagus (IHO).<h4>Methods</h4>Necropsy records and the histopathology findings in the oesophagus were reviewed for the period 1990 to 1995. Six cases (0.7%) of IHO were found among 919 necropsy cases. Clinic... |
10193254 | Randomised trial of three doses of inhaled nitric oxide in acute respiratory distress syndrome. | <h4>Background</h4>Inhaled nitric oxide (iNO) is a potential therapeutic agent for the management of acute respiratory distress syndrome (ARDS). Concerns remain, however, regarding the potential toxicity from iNO and/or its oxidative derivatives and methaemoglobinaemia.<h4>Aims</h4>To determine the risk of toxicity fro... |
9894838 | Molecular recognition properties of the C-terminal Sh3 domain of the Cbl associated protein, Cap. | A phage-displayed combinatorial peptide library was used to define the specificity of one of the three Src homology 3 (SH3) domains in a novel cytoskeletal protein, named CAP, for Cbl Associated Protein. The C-terminal SH3 domain was used to affinity select peptides with the consensus, PXPPXRXSSL, from a library of X6P... |
9885309 | Characterization of an inclusion complex of cholesterol and hydroxypropyl-beta-cyclodextrin. | Interactions between endogenous cholesterol and cyclodextrins have been investigated by several researchers, and they found altered skin penetration of some drugs, membrane disruption, and extraction of cholesterol from the large lipoprotein particles or animal fat. In the present study, an inclusion complex composed o... |
9886776 | Comparative analysis of crossover exchanges and chiasmata in Allium cepa x fistulosum after genomic in situ hybridization (GISH). | Genomic in situ hybridization (GISH) successfully differentiated homoeologous genomes in the inter-specific hybrid Allium cepa x fistulosum, thus allowing the detection of reciprocal crossover events as label exchanges in separating anaphase I chromosomes. Three of the eight chromosome pairs were positively identified ... |
9886775 | Heterochromatin discrimination in Aegilops speltoides by simultaneous genomic in situ hybridization. | Simultaneous genomic in situ hybridization with probe preannealing (SP-GISH) was used for discriminating Aegilops speltoides chromosome regions by their relatedness to DNA of other species. We used a hybridization mixture of two differently labelled DNAs, one from the species used for chromosome spread preparations and... |
9886774 | Non-Rabl patterns of centromere and telomere distribution in the interphase nuclei of plant cells. | At the anaphase of cell divisions, the divided chromosomes move to the two poles, with the centromeres as heads and telomeres as tails. Such a polarized orientation of centromeres and telomeres is believed to be preserved in the interphase and is known as Rabl model. We analyzed the distributions of centromeres and tel... |
9886773 | Cytochalasin D and latrunculin affect chromosome behaviour during meiosis in crane-fly spermatocytes. | Living crane-fly spermatocytes were treated with 10-20 microg/ml cytochalasin D (CD) or 0.3 microg/ml latrunculin (LAT) at various stages of meiosis I. The drugs had the same effects on chromosome behaviour, but CD effects were reversible and LAT effects generally were not. When applied in mid-prometaphase to metaphase... |
9886772 | Chromosomal strategies for adaptation to univalency. | The orientation and segregation behaviour of different types of univalents, namely sex chromosomes, B chromosomes and autosomal univalents, were analysed in living spermatocytes of eight evolutionarily distant grasshopper species. The meiotic behaviour of each univalent was characterized in terms of velocity of prometa... |
9886771 | A karyotypic analysis of nilgai, Boselaphus tragocamelus (Artiodactyla: Bovidae). | A combination of chromosomal banding and fluorescence in situ hybridization (FISH) was used to characterize the karyotype of Boselaphus tragocamelus (nilgai) relative to the domestic cattle standard karyotype. G-, Q- and C-band karyotypes of nilgai are presented, and the chromosomal complement of nilgai is determined t... |
9884562 | [Comparative study of artificial circulation for the liver after cardiogenic shock: pulsatile or nonpulsatile?]. | Because of multiple organ failure (MOF), the survival rate of patients with mechanical circulatory support has not been satisfactory, The purpose of this study is to estimate the effects of pulsatile and nonpulsatile artificial circulation on hepatic microcirculation and function. Cardiogenic shock was induced experime... |
9881391 | A novel leucocyte-depleting filter for use in continuous venovenous haemofiltration: preliminary in vitro studies. | Multiple organ failure (MOF) secondary to circulatory shock, sepsis, or trauma was first described over 20 years ago. Despite much research effort and clinical trials of biological response modifiers, MOF continues to be the leading cause of death in both medical and surgical intensive care units (ICU). MOF is associat... |
9871980 | Infrared spectroscopy of glycolipids. | The application of infrared spectroscopy to the physicochemical characterization of glycolipids as biologically important membrane constituents is described. In this contribution, the analysis of diacyl- and sphingosine-based (cerebroside, ganglioside) oligosaccharides and the class of lipid A-anchored lipooligo- and p... |
9871972 | Biosensor for on-line measurement of bovine progesterone during milking. | Reproductive management is a major financial concern of the dairy industry, with missed estrus detection a main cause of lost income. A biosensor was developed for on-line measurement of progesterone in bovine milk and detection of estrus. The biosensor used an enzyme immunoassay format for molecular recognition, which... |
9870400 | Development of a simple high-performance capillary electrophoretic method with on-line mode in capillary derivatization for the determination of spermidine. | A new high-performance capillary electrophoretic (HPCE) method with an on-line mode in-capillary derivatization (ICD) procedure for determinations of some amines using 20 mmol/L sodium dodecyl sulfate (SDS) - 2 mmol/L o-phthalaldehyde (OPA) - 2 mmol/L N-acetylcysteine (NAC) - 20 mmol/L phosphate-borate buffer [9] has p... |
9870390 | Capillary electrophoresis separation of the new anti-AIDS agents 9-(2-phosphonylmethoxyethyl)adenine and 9-(2-phosphonylmethoxyethyl)-2,6-diaminopurine in mixtures with some monoribonucleotides or the most common deoxynucleotides. | The present work describes an electrophoretic method for the separation and determination of the new antivirals, 9-(2-phosphonylmethoxyethyl)adenine (PMEA) and 9-(2-phosphonylmethoxyethyl)-2,9-diaminopurine (PMEDAP) in model mixtures with some monoribonucleotide isomers (3'-AMP, 2'-CMP, 3'-CMP, 3'-GMP, 2'-GMP, 3'-UMP, ... |
9870389 | Effects of various anionic chiral selectors on the capillary electrophoresis separation of chiral phenethylamines and achiral neutral impurities present in illicit methamphetamine. | In this study, various anionic chiral selectors were investigated for the capillary electrophoresis (CE) separation of six chiral phenethylamines and three achiral neutral impurities which are commonly identified in illicit methamphetamine. Analyses were carried out at pH 8 (high osmotic flow) with untreated capillarie... |
9870383 | Use of cyclodextrins in capillary electrophoresis: resolution of tramadol enantiomers. | Capillary zone electrophoresis was successfully applied to the enantiomeric resolution of racemic tramadol. Both uncoated and polyacrylamide-coated capillaries were tested for method optimization using either negatively charged or native cyclodextrins (CD) added to the background electrolyte (BGE). The resolution was s... |
9870377 | Method development strategies for the enantioseparation of drugs by capillary electrophoresis using cyclodextrins as chiral additives. | General strategies for the development of capillary electrophoretic methods for the enantiomeric separation of basic, acidic or neutral drugs were developed. For all kinds of compounds, the use of a buffer made of 100 mM phosphoric acid adjusted to pH 3 with triethanolamine and containing anionic and/or uncharged cyclo... |
9870376 | Separation of chiral compounds by capillary electrophoresis. | This review presents the different chiral selectors used in capillary electrophoresis (CE) for the separation of enantiomers. The use of charged cyclodextrins, crown ethers, polysaccharides, proteins, natural and synthetic micelles, macrocyclic antibiotics and ergot alkaloids is discussed in detail. Neutral native and ... |
9864473 | Noncovalent complexes between poly(ethylene glycol) and proteins. | A new method of formation of noncovalent complexes between poly(ethylene glycol) (PEG) and proteins (alpha-chymotrypsin (ChT), lysozyme, bovine serum albumin) under high pressure has been developed. The existence of polymer in complexes was proved using 3H-labeled PEG. Complexes between PEG and ChT were studied in deta... |
9862067 | Development of a toxin-binding agent as a treatment for tunicaminyluracil toxicity: protection against tunicamycin poisoning of sheep. | <h4>Objective</h4>To assess the ability of certain derivatives of beta-cyclodextrin to treat sheep affected by tunicaminyluracil toxicity, using tunicamycin poisoning as a model system.<h4>Design</h4>Controlled treatment trial.<h4>Animals</h4>One hundred and sixty Merino wethers were used in the studies.<h4>Procedure</... |
9860188 | Effect of various adjuvants on secondary immune response in chickens. | Stimulatory effects of several types of adjuvants on secondary antibody response to inactivated Newcastle disease virus (iNDV) were examined in chickens. For this purpose, animals were primed with iNDV without adjuvant resulting in a low but significant antibody response, boosted with iNDV plus adjuvant 3 weeks later, ... |
9853355 | Increasing the cyclodextrin complexation of drugs and drug biovailability through addition of water-soluble polymers. | For a variety of reasons, including cost, production capabilities and toxicology, the amounts of cyclodextrin (CD) that can be included in drug formulations is limited and, thus, it is important to develop methods which can be applied to enhance the complexation efficacy. Moreover, bioavailability of drugs in CD contai... |
9850611 | New developments in the molecular pharmacology of the myo-inositol 1,4,5-trisphosphate receptor. | Receptor-mediated activation of phospholipase C to generate inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] is a ubiquitous signalling pathway in mammalian systems. A family of three IP3 receptor subtype monomers form functional tetramers, which act as effectors for Ins(1,4,5)P3, providing a ligand-gated channel that allow... |
9849615 | The structure of human interferon-beta: implications for activity. | Interferons (IFNs) are potent extracellular protein mediators of host defence and homoeostasis. This article reviews the structure of human IFN-beta (HuIFN-beta), in particular in relation to its activity. The recently determined crystal structure of HuIFN-beta provides a framework for understanding of the mechanism of... |
9849983 | Management of neonatal candidiasis. Neonatal Candidiasis Study Group. | <h4>Objective</h4>To identify areas of consensus and controversy in the management of neonatal candidiasis.<h4>Methods</h4>A questionnaire was distributed to US-based members of the Pediatric Infectious Diseases Society and a sampling of US neonatologists.<h4>Results</h4>Three hundred eighty evaluable questionnaires we... |
9849898 | Functional heterodimeric amino acid transporters lacking cysteine residues involved in disulfide bond. | The protein mediating system L amino acid transport, AmAT-L, is a disulfide-linked heterodimer of a permease-related light chain (AmAT-L-lc) and the type II glycoprotein 4F2hc/ CD98. The Schistosoma mansoni protein SPRM1 also heterodimerizes with h4F2hc, inducing amino acid transport with different specificity. In this... |
9848677 | Isolation and characterization of beta-cyclodextrin sulfates by preparative gradient polyacrylamide gel electrophoresis, capillary electrophoresis and electrospray ionization - mass spectrometry. | A beta-cyclodextrin sulfate mixture has been fractionated using discontinuous gradient polyacrylamide gel electrophoresis. Semidry electrotransfer of the sample onto a positively charged nylon membrane and visualization of a portion of this membrane with Alcian blue stain showed multiple bands. The bands were cut from ... |
9848671 | Investigation of micelles and anionic cyclodextrins as pseudostationary phases for the capillary electrophoresis separation of oligosaccharides derivatized with 2-amino-benzamide. | Oligomers of glucose and oligosaccharides released from glycoproteins were derivatized with 2-aminobenzamide. As this fluorophore imparts no charge to the oligosaccharides, several strategies were investigated to achieve capillary electrophoresis (CE) separation of both neutral and charged derivatized glycans. Micellar... |
9848279 | Cholesterol induced variations of membrane dynamics related to the induction of apoptosis in mouse thymocytes. | <h4>Purpose</h4>To evaluate the involvement of cholesterol induced variations of membrane dynamics in mouse thymocyte apoptosis.<h4>Materials and methods</h4>Membranes of thymocytes of RK mice were enriched with cholesterol using methyl-beta-cyclodextrins as carriers. Spontaneous apoptosis was compared with apoptosis i... |
9845970 | Molecular modeling studies of human A3 adenosine antagonists: structural homology and receptor docking. | Molecular modeling studies were conducted on various chemically diverse classes of human A3 adenosine receptor antagonists (hA3ANTs), such as adenines, xanthines, triazoloquinazolines, flavonoids, thiazolopyridines, 6-phenyl-1, 4-dihydropyridines, and 6-phenylpyridines. Using a combination of ab initio quantum mechanic... |
9846893 | Tau glycation is involved in aggregation of the protein but not in the formation of filaments. | A tau peptide, peptide 2R, with capacity for self assembly into filaments was used as a model to test the role of glycation on tau assembly or aggregation. Our results indicate that glycation of that peptide facilitates dimer formation but not assembly into filaments. However, glycation of tau results in the bundling o... |
9843425 | Translocation of human calcitonin in respiratory nasal epithelium is associated with self-assembly in lipid membrane. | We studied the mechanisms involved in the translocation of human calcitonin (hCT) through excised bovine nasal mucosa (net mucosal-to-serosal permeability approximately 10(-)5 cm s-1). To determine structural requirements for the suggested vesicular internalization two carboxyfluorescein-labeled (fl) hCT fragments, the... |
9842720 | Retention behavior of positional isomers of disubstituted cyclomalto-oligosaccharide (cyclodextrin) derivatives on an ODS column. | The correlation between hydrophobic effects and structures of three and four positional isomers of 6(1),6n-di-O-triphenylmethyl (trityl)- or 6(1),6n-di-O-tert.- butyldimethylsilyl (tert.-BuMe2Si)-cyclomaltohexaoses (cG6s, alpha-cyclodextrin) (n = 2-4), -cyclomaltoheptaoses (cG7s, beta-cyclodextrin) (n = 2-4), and -cycl... |
9832550 | Unc-45 mutations in Caenorhabditis elegans implicate a CRO1/She4p-like domain in myosin assembly. | The Caenorhabditis elegans unc-45 locus has been proposed to encode a protein machine for myosin assembly. The UNC-45 protein is predicted to contain an NH2-terminal domain with three tetratricopeptide repeat motifs, a unique central region, and a COOH-terminal domain homologous to CRO1 and She4p. CRO1 and She4p are fu... |
9834959 | Solubility properties of racemic praziquantel and its enantiomers. | The purpose of this study was to characterize the solubility and thermodynamic properties of the optical isomers of the anti-schistosomal drug, praziquantel (PZQ) and to compare these properties to those of the racemic product used in commercial preparations (Biltricide, generic drugs). The crystalline enantiomers of P... |
9834031 | Surface-promoted replication and exponential amplification of DNA analogues. | Self-replicating chemical systems have been designed and studied to identify the minimal requirements for molecular replication, to translate the principle into synthetic supramolecular systems and to derive a better understanding of the scope and limitations of self-organization processes that are believed to be relev... |
9833990 | Co-administration of a water-soluble polymer increases the usefulness of cyclodextrins in solid oral dosage forms. | <h4>Purpose</h4>The aim of this study was to investigate the effect of cyclodextrins (beta-CD, HP-beta-CD and (SBE)7m-beta-CD), and co-administration of a water-soluble polymer (HPMC) and cyclodextrins, on the oral bioavailability of glibenclamide in dogs.<h4>Methods</h4>Effects of cyclodextrins on the aqueous solubili... |
9826660 | Nitrosative stress: metabolic pathway involving the flavohemoglobin. | Nitric oxide (NO) biology has focused on the tightly regulated enzymatic mechanism that transforms L-arginine into a family of molecules, which serve both signaling and defense functions. However, very little is known of the pathways that metabolize these molecules or turn off the signals. The paradigm is well exemplif... |
9828002 | pH-induced conformational changes of membrane-bound influenza hemagglutinin and its effect on target lipid bilayers. | Influenza virus hemagglutinin (HA) has served as a paradigm for both pH-dependent and -independent viral membrane fusion. Although large conformational changes were observed by X-ray crystallography when soluble fragments of HA were subjected to fusion-pH conditions, it is not clear whether the same changes occur in me... |
9827998 | Singular points of protein beta-sheets. | Protein beta-sheets can be regarded as surfaces. Two surfaces can be connected along a common edge to form a larger surface, or two edges of a surface can coalesce to form a closed sheet such as a beta-barrel. Singular points are locations where these connections are not perfect. In protein beta-sheets, a singular poin... |
9825700 | Supramolecular cationic tetraruthenated porphyrin and light-induced decomposition of 2'-deoxyguanosine predominantly via a singlet oxygen-mediated mechanism. | The tetraruthenated porphyrin, mu-[meso-5,10,15,20-tetra(pyridyl)porphyrin]tetrakis[bis-(bipyridine) chloride ruthenium(II)] (TRP) is a supramolecular cationic species. The aim of the present investigation was to evaluate the photodynamic properties of TRP and Zn-TRP to damage DNA with emphasis on the mechanistic aspec... |
9822813 | A model for early events in the assembly pathway of cyanobacterial phycobilisomes. | Biological self-assembly is remarkable in its fidelity and in the efficient production of intricate molecular machines and functional materials from a heterogeneous mixture of macromolecules. The phycobilisome, a light-harvesting structure of cyanobacteria, presents the opportunity to study an in vivo assembly process ... |
9822710 | Plasma membrane cholesterol is a key molecule in shear stress-dependent activation of extracellular signal-regulated kinase. | Shear stress, the dragging force generated by fluid flow, differentially activates extracellular signal-regulated kinase (ERK) and c-Jun NH2-terminal kinase (JNK) in bovine aortic endothelial cells (BAEC) (Jo, H., Sipos, K., Go, Y. M., Law, R., Rong, J., and McDonald, J. M. (1997) J. Biol. Chem. 272, 1395-1401). Here, ... |
9822631 | Effects of substrate and inhibitor binding on proteolysis of isoleucyl-tRNA synthetase from Staphylococcus aureus. | Binding of ligands to isoleucyl-tRNA synthetase (IleRS; E) from Staphylococcus aureus was investigated through effects on proteolytic digestion. Approximately 50-fold higher concentrations of protease (trypsin or chymotrypsin) were required to inactivate IleRS after incubation with substrates and formation of the E. Il... |
9822629 | Characterization of isoleucyl-tRNA synthetase from Staphylococcus aureus. I: Kinetic mechanism of the substrate activation reaction studied by transient and steady-state techniques. | The kinetic mechanism for the amino acid activation reaction of Staphylococcus aureus isoleucyl-tRNA synthetase (IleRS; E) has been determined from stopped-flow measurements of the tryptophan fluorescence associated with the formation of the enzyme-bound aminoacyl adenylate (E.Ile-AMP; Scheme 1). Isoleucine (Ile) binds... |
9823719 | Studies of protein binding to nonpolar solutes by using zonal elution and high-performance affinity chromatography: interactions of cis- and trans-clomiphene with human serum albumin in the presence of beta-cyclodextrin. | High-performance affinity chromatography and zonal elution studies were used to examine the binding that takes place between the drug clomiphene and the protein human serum albumin (HSA). Equations were derived to describe the behavior of zonal elution experiments in which a solubilizing agent is present in the mobile ... |
9823718 | Modeling and optimization of enantioseparation by capillary electrochromatography. | Both electrophoretic and chromatographic transport mechanisms are combined in electrochromatographic separation. In this paper, we developed a model of enantioselectivity in capillary electrochromatography (CEC) which can be applied in the separation of both neutral and ionic compounds. The overall selectivity in enant... |
9824157 | Design and properties of a Myc derivative that efficiently homodimerizes. | bHLH and bHLHZip are highly conserved structural domains mediating DNA binding and specific protein-protein interactions. They are present in a family of transcription factors, acting as dimers, and their selective dimerization is utilized to switch on and off cell proliferation, differentiation or apoptosis. Myc is a ... |
9823971 | Clearance of yttrium-90-labelled anti-tumour antibodies with antibodies raised against the 12N4 DOTA macrocycle. | Radioimmunotherapy (RIT) is currently limited by toxicity to normal tissues as a result of prolonged circulating radioantibody in the blood. In this study, the use of a clearing antibody was investigated (second antibody) in an attempt to reduce blood background levels of [90Y]A5B7 immunoglobulin G (IgG) activity, and,... |
9819371 | Estrogen blocks M-CSF gene expression and osteoclast formation by regulating phosphorylation of Egr-1 and its interaction with Sp-1. | Central to the pathogenesis of osteoporosis is the ability of estrogen deficiency to increase osteoclast formation by enhancing stromal cell production of the osteoclastogenic cytokine macrophage colony-stimulating factor (M-CSF). We report that stromal cells from ovariectomized mice exhibit increased casein kinase II-... |
9820694 | Threshold values of intramucosal pH and mucosal-arterial CO2 gap during shock resuscitation. | <h4>Background</h4>The gastric intramucosal pH (pHi) and gastric mucosal-arterial CO2 gap (GAP) estimate visceral perfusion and predict outcome. Threshold values of these variables for use during resuscitation, however, remain poorly defined. The purpose of this study was to develop clinically derived cutoffs for both ... |
9820174 | Antiproliferative effect of methyl-beta-cyclodextrin in vitro and in human tumour xenografted athymic nude mice. | The anti-tumour activity of methyl-beta-cyclodextrin (MEBCD), a cyclic oligosaccharide known for its interaction with the plasma membrane, was investigated in vitro and in vivo and compared with that of doxorubicin (DOX) in the human tumour models MCF7 breast carcinoma and A2780 ovarian carcinoma. In vitro proliferatio... |
9818319 | Dysprosium-DOTA-PAMAM dendrimers as macromolecular T2 contrast agents. Preparation and relaxometry. | <h4>Rationale and objectives</h4>The authors have investigated dysprosium [Dy]-DOTA-PAMAM, generation 5 (G = 5) dendrimers as a possible new class of macromolecular T2 contrast agents. The use of DOTA provides a metal complex with greater stability than can be achieved using DTPA as ligand, an important factor in the d... |
9817758 | The NH2 terminus of titin spans the Z-disc: its interaction with a novel 19-kD ligand (T-cap) is required for sarcomeric integrity. | Titin is a giant elastic protein in vertebrate striated muscles with an unprecedented molecular mass of 3-4 megadaltons. Single molecules of titin extend from the Z-line to the M-line. Here, we define the molecular layout of titin within the Z-line; the most NH2-terminal 30 kD of titin is located at the periphery of th... |
9817755 | Direct pathway from early/recycling endosomes to the Golgi apparatus revealed through the study of shiga toxin B-fragment transport. | Shiga toxin and other toxins of this family can escape the endocytic pathway and reach the Golgi apparatus. To synchronize endosome to Golgi transport, Shiga toxin B-fragment was internalized into HeLa cells at low temperatures. Under these conditions, the protein partitioned away from markers destined for the late end... |
9815176 | Biotin reagents for antibody pretargeting. 3. Synthesis, radioiodination, and evaluation of biotinylated starburst dendrimers. | We are investigating the hypothesis that biotin multimers can be used with streptavidin and monoclonal antibody conjugates in cancer pretargeting protocols to provide a method of increasing the amount of radioactivity bound on cancer cells in patients. As part of that investigation, a series of biotinylated Starburst d... |
9815175 | Self-assembly of polyamine-poly(ethylene glycol) copolymers with phosphorothioate oligonucleotides. | The cationic copolymers for DNA delivery were synthesized by conjugating poly(ethylene glycol) (PEG) and polyamines: polyspermine (PSP) and polyethyleneimine (PEI). These molecules spontaneously form electrostatic complexes with a model 24-mer phoshorothioate oligonucleotide, T24 (PS-ODN). The copolymer complexes are w... |
9815160 | Novel derivatives of cyclodextrins, modified with poly(ethylene oxide) and their complexation properties. | A new family of bouquet-like molecules based on cyclodextrins is described. These compounds were obtained by polymerization of ethylene oxide. This reaction was initiated by primary and secondary hydroxyl groups of cyclodextrins, which constitute an organizing core. Analysis of structure and composition of conjugates b... |
9813081 | Molecular architecture of the yeast nuclear pore complex: localization of Nsp1p subcomplexes. | The nuclear pore complex (NPC), a supramolecular assembly of approximately 100 different proteins (nucleoporins), mediates bidirectional transport of molecules between the cytoplasm and the cell nucleus. Extensive structural studies have revealed the three- dimensional (3D) architecture of Xenopus NPCs, and eight of th... |
9813080 | Recruitment of phosphorylated chromatin assembly factor 1 to chromatin after UV irradiation of human cells. | The subcellular distribution and posttranslational modification of human chromatin assembly factor 1 (CAF-1) have been investigated after UV irradiation of HeLa cells. In an asynchronous cell population only a subfraction of the two large CAF-1 subunits, p150 and p60, were found to exist in a chromatin-associated fract... |
9812912 | Sequences within the amino terminus of ApoB100 mediate its noncovalent association with apo(a). | Although sequences within the C terminus of apolipoprotein B (apoB) have been implicated in the formation of covalent lipoprotein(a) [Lp(a)] particles, sequences in apoB that mediate initial noncovalent interaction with apo(a) remain to be characterized. To address this question, we have used an affinity chromatography... |
9811809 | Polyazamacrolides from ladybird beetles: ring-size selective oligomerization. | The pupal defensive secretion of the 24-pointed ladybird beetle, Subcoccinella vigintiquatuorpunctata, consists of a mixture of macrocyclic polyamines, dominated by the three dimeric, 30-membered macrocycles 11-13, derived from the two building blocks 11-(2-hydoxyethylamino)-5-tetradecenoic acid (9) and 11-(2-hydoxyeth... |
9801315 | The FIS protein fails to block the binding of DnaA protein to oriC, the Escherichia coli chromosomal origin. | The Escherichia coli chromosomal origin contains several bindings sites for factor for inversion stimulation (FIS), a protein originally identified to be required for DNA inversion by the Hin and Gin recombinases. The primary FIS binding site is close to two central DnaA boxes that are bound by DnaA protein to initiate... |
9801313 | Reconstitution of DNA topoisomerase VI of the thermophilic archaeon Sulfolobus shibatae from subunits separately overexpressed in Escherichia coli. | DNA topoisomerase VI from the hyperthermophilic archaeon Sulfolobus shibatae is the prototype of a novel family of type II DNA topoisomerases that share little sequence similarity with other type II enzymes, including bacterial and eukaryal type II DNA topoisomerases and archaeal DNA gyrases. DNA topoisomerase VI relax... |
9801312 | Structural flexibility of a DNA hairpin located in the long terminal repeat of the Drosophila 1731 retrotransposon. | The structure of the DNA binding site of the Nuclear single-stranded Binding Factor (NssBF), located in the long terminal repeat of the Drosophila 1731 retrotransposon, was investigated by melting temperature experiments, chemical probing and fluorescence measurements using a macrocyclic bis-acridine. The most probable... |
9813079 | Differential effects of sphingomyelin hydrolysis and cholesterol transport on oxysterol-binding protein phosphorylation and Golgi localization. | The deposition of de novo synthesized and lipoprotein-derived cholesterol at the plasma membrane and transport to the endoplasmic reticulum is dependent on sphingomyelin (SM) content. Here we show that hydrolysis of plasma membrane SM in Chinese hamster ovary cells by exogenous bacterial sphingomyelinase resulted in en... |
9811935 | Targeted replacement of normal and mutant CFTR sequences in human airway epithelial cells using DNA fragments. | Recent studies have reported that mutant genomic cystic fibrosis (CF) transmembrane conductance regulator ( CFTR ) sequences can be corrected in transformed CF airway epithelial cell lines by targeted replacement with small fragments of DNA with wild-type sequence. To determine if the observed genotype modification fol... |
9814760 | Inhibition of viral gene expression by human ribonuclease P. | External guide sequences (EGSs) are small RNA molecules which consist of a sequence complementary to a target mRNA and render the target RNA susceptible to degradation by ribonuclease P (RNase P). EGSs were designed to target the mRNA encoding thymidine kinase (TK) of herpes simplex virus 1 for degradation. These EGSs ... |
9806969 | Delimiting the binding site for quaternary ammonium lidocaine derivatives in the acetylcholine receptor channel. | The triethylammonium QX-314 and the trimethylammonium QX-222 are lidocaine derivatives that act as open-channel blockers of the acetylcholine (ACh) receptor. When bound, these blockers should occlude some of the residues lining the channel. Eight residues in the second membrane-spanning segment (M2) of the mouse-muscle... |
9806908 | Cholesterol regulates oxysterol binding protein (OSBP) phosphorylation and Golgi localization in Chinese hamster ovary cells: correlation with stimulation of sphingomyelin synthesis by 25-hydroxycholesterol. | Sphingomyelin (SM) and cholesterol content is positively correlated in cellular membranes, and in several pathological and experimental conditions there is evidence for coregulation. The potential role of oxysterols and oxysterol binding protein (OSBP) in mediating the coregulation of cholesterol and SM was examined us... |
9806884 | Polyunsaturated fatty acid enrichment enhances endothelial cell-induced low-density-lipoprotein peroxidation. | Oxidative modification of low-density lipoprotein (LDL) is an important feature in the initiation and progression of atherosclerosis. LDL modification by endothelial cells was studied after supplementation of the cells with oleic acid and polyunsaturated fatty acids (PUFA) of the n-6 and n-3 series. In terms of the lip... |
9804696 | Use of papain as a model for the structure-based design of cathepsin K inhibitors: crystal structures of two papain-inhibitor complexes demonstrate binding to S'-subsites. | Papain has been used as a surrogate enzyme in a drug design effort to obtain potent and selective inhibitors of cathepsin K, a new member of the papain superfamily of cysteine proteases that is selectively and highly expressed in osteoclasts and is implicated in bone resorption. Here we report the crystal structures of... |
9804997 | Magainins as paradigm for the mode of action of pore forming polypeptides. | Magainins are a class of antimicrobial peptides discovered in the skin of Xenopus laevis. The peptides kill bacteria by permeabilizing the cell membranes without exhibiting significant toxicity against mammalian cells, and are a promising candidate for a new antibiotic of therapeutic value. The main target of the pepti... |
9804863 | Single-molecule high-resolution structure and electron conduction of photosystem II from scanning tunneling microscopy and spectroscopy. | Scanning tunneling microscopy (STM) and spectroscopy (STS) were used to obtain the first direct high resolution ( approximately 0.3 nm) images of single isolated Photosystem II (PS II) molecules, and to determine the supramolecular organization of oxygen-evolving PS II core complexes and PS II membrane fragments includ... |
9806617 | The photobiology of photodynamic therapy: cellular targets and mechanisms. | Photodynamic therapy (PDT) is dependent on the uptake of a photosensitizing dye, often a porphyrin-related macrocycle, by the tumor or other abnormal tissue that is to be treated, the subsequent irradiation of the tumor with visible light of an appropriate wavelength matched to the absorption spectrum of the dye, and m... |
9801332 | Use of the cell division protein FtsZ as a means of differentiating among Bartonella species. | Genes coding for homologs of the highly conserved cell division protein FtsZ were isolated from Bartonella henselae and Bartonella quintana, the causative agents of cat scratch disease and trench fever, respectively. DNA fragments coding for the ftsZ open reading frames (ORFs) were cloned into Escherichia coli followin... |
9802905 | Control of cyclin D1, p27(Kip1), and cell cycle progression in human capillary endothelial cells by cell shape and cytoskeletal tension. | The extracellular matrix (ECM) plays an essential role in the regulation of cell proliferation during angiogenesis. Cell adhesion to ECM is mediated by binding of cell surface integrin receptors, which both activate intracellular signaling cascades and mediate tension-dependent changes in cell shape and cytoskeletal st... |
9802895 | tRNA nuclear export in saccharomyces cerevisiae: in situ hybridization analysis. | To understand the factors specifically affecting tRNA nuclear export, we adapted in situ hybridization procedures to locate endogenous levels of individual tRNA families in wild-type and mutant yeast cells. Our studies of tRNAs encoded by genes lacking introns show that nucleoporin Nup116p affects both poly(A) RNA and ... |
9799225 | Periplasmic chaperone recognition motif of subunits mediates quaternary interactions in the pilus. | The class of proteins collectively known as periplasmic immunoglobulin-like chaperones play an essential role in the assembly of a diverse set of adhesive organelles used by pathogenic strains of Gram-negative bacteria. Herein, we present a combination of genetic and structural data that sheds new light on chaperone-su... |
9797234 | Prospective randomized comparison of imipenem-cilastatin and piperacillin-tazobactam in nosocomial pneumonia or peritonitis. | Nosocomial pneumonia and acute peritonitis may be caused by a wide array of pathogens, and combination therapy is often recommended. We have previously shown that imipenem-cilastatin monotherapy was as efficacious as the combination of imipenem-cilastatin plus netilmicin in these two settings. The efficacy of imipenem-... |
9791137 | DdlN from vancomycin-producing Amycolatopsis orientalis C329.2 is a VanA homologue with D-alanyl-D-lactate ligase activity. | Vancomycin-resistant enterococci acquire high-level resistance to glycopeptide antibiotics through the synthesis of peptidoglycan terminating in D-alanyl-D-lactate. A key enzyme in this process is a D-alanyl-D-alanine ligase homologue, VanA or VanB, which preferentially catalyzes the synthesis of the depsipeptide D-ala... |
9791118 | Characterization of circular plasmid dimers in Borrelia burgdorferi. | We have inactivated the ospC, oppAIV, and guaB genes on the 26-kb circular plasmid of Borrelia burgdorferi (cp26) by allelic exchange. On several occasions following such transformations, the cp26 of transformants had an aberrant mobility through agarose gels. Characterization of these cp26 molecules showed that the pl... |
9791111 | Multiple in vivo roles for the -12-region elements of sigma 54 promoters. | Alignment of sigma 54-dependent promoters indicates conservation of two sequence elements. Six nucleotides in the downstream -12 element were mutated individually to each nonconsensus nucleotide. mRNA levels were measured in vivo for each promoter under strongly activating conditions. The results showed that the consen... |
9791110 | Identification of an N-terminal region of sigma 54 required for enhancer responsiveness. | Sigma 54 associates with bacterial core RNA polymerase and converts it into an enhancer-responsive enzyme. Deletion of the N-terminal 40 amino acids is known to result in loss of the ability to respond to enhancer binding proteins. In this work PCR mutagenesis and genetic screens were used to identify a small patch, fr... |
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