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29711472 | A Molecular Chameleon: Chromophoric Sensing by a Self-Complexing Molecular Assembly. | A color change from purple to green takes place on addition of tetrathiafulvalene (TTF) to the macrobicyclic receptor 1<sup>4+</sup> , which is composed of a cyclobis(paraquat-p-phenylene) tetracation that shares one of its paraphenylene rings with a 1,5-naphthoparaphenylene-[36]crown-10 macrocycle. The TTF molecule fo... |
29711465 | Stereospecificity and Self-Selectivity in the Generation of a Chiral Molecular Tetrahedron by Metal-Assisted Self-Assembly. | The chiral bidentate ligand (S,S)-1 reacts stereospecifically with Ga<sup>3+</sup> to generate a [Ga<sub>4</sub> (L)<sub>6</sub> ]<sup>12-</sup> molecular tetrahedron although similar ligands generate [Ga<sub>2</sub> (L)<sub>3</sub> ]<sup>6-</sup> complexes. The assembly of this complex is self-selective as a racemic m... |
29711378 | Stabilities of Hydrogen-Bonded Supramolecular Complexes with Various Numbers of Single Bonds: Attempts To Quantify a Dogma in Host-Guest Chemistry. | The disadvantage of flexible bonds in supramolecular host-guest complexes is much smaller than usually assumed. In the association of dicarboxlic acids with diamides (shown on the right), freely rotatable single bonds have only a minor disadvantageous influence on the free energy of complexation ΔG<sub>cplx</sub> . Fro... |
29711375 | Controllable Intramolecular Motions That Generate Fluorescent Signals for a Metal Scorpionate Complex. | Simply by changing the pH value, the side chain of complex 1 can be reversibly moved between two positions. Coordination to the metal center through the nitrogen atom of the side chain at moderate pH values is accompanied by a decrease in fluorescence intensity (from I<sub>F</sub> =100% to I<sub>F</sub> =60%). A furthe... |
11819259 | Experimental research on production and uptake sites of TNFalpha in rats with acute hemorrhagic necrotic pancreatitis. | AIM:To determine the site of production and uptake of tumor necrotic factor alpha (TNFalpha),and evaluate the relationship between serum TNFalphaand pla-sma endotoxin (ET) in rats with acute hemorrhagic necrotic pancreatitis (AHNP).METHODS:Sprague Dawley rats were divided into AHNP group and control group (n = 12). AHN... |
21647973 | Polymer electrolytes for lithium-ion batteries. | The motivation for lithium battery development and a discussion of ion conducting polymers as separators begin this review, which includes a short history of polymer electrolyte research, a summary of the major parameters that determine lithium ion transport in polymer matrices, and consequences for solid polymer elect... |
18967114 | Potentiometric study of the mixed-metal complex formation of tetracarboxylate-18-crown-6 with aluminum and alkali and alkaline earth cations. | We give evidence for the formation of mixed-metal complexes of tetracarboxylate-18-crown-6 in the form of Al(3+)-macrocycle-M(Z+), with M(Z+) being an alkali or an alkaline earth cation. These binuclear systems are characterized by potentiometric p[H] titrations and the equilibrium constants for all major complexes for... |
16349535 | Analysis of BIOLOG GN Substrate Utilization Patterns by Microbial Communities. | BIOLOG GN plates are increasingly used to characterize microbial communities by determining the ability of the communities to oxidize various carbon sources. Studies were done to determine whether the BIOLOG GN plate assay accurately reflects the catabolic potential of the inoculum used. To gain insight into which popu... |
9554840 | Switching supramolecular polymeric materials with multiple length scales | It was demonstrated that polymeric supramolecular nanostructures with several length scales allow straightforward tailoring of hierarchical order-disorder and order-order transitions and the concurrent switching of functional properties. Poly(4-vinyl pyridine) (P4VP) was stoichiometrically protonated with methane sulfo... |
11672126 | Highly Regioselective Palladium-Catalyzed Thiocarbonylation of Allenes with Thiols and Carbon Monoxide. | A series of mono- and di-substituted allenes underwent direct thiocarbonylation with thiols and carbon monoxide to form the corresponding beta,gamma-unsaturated thioesters in 73-94% yields. This reaction requires catalytic quantities of Pd(OAc)(2) (3 mol %) and triphenylphosphine (12 mol %) in THF under an atmosphere o... |
11672123 | Synthesis of 1,19-Aza-1,19-desoxy-avermectin B(1a): The First Avermectin Macrolactam. | The first synthesis of 1,19-aza-1,19-desoxy-avermectin B(1a) (2) is described. This new macrolactam, prepared efficiently from avermectin B(1a) (1a) in seven steps, was designed to form an intramolecular hydrogen bond between the amide carbonyl and the adjacent C7 tertiary hydroxyl via a six-center hydrogen bonding net... |
9525635 | Type D retrovirus capsid assembly and release are active events requiring ATP. | Mason-Pfizer monkey virus (M-PMV), the prototype type D retrovirus, differs from most other retroviruses by assembling its Gag polyproteins into procapsids in the cytoplasm of infected cells. Once assembled, the procapsids migrate to the plasma membrane, where they acquire their envelope during budding. Because the pro... |
9525624 | Human parvovirus B19 nonstructural (NS1) protein induces apoptosis in erythroid lineage cells. | Infection of erythroid-lineage cells by human parvovirus B19 is characterized by a gradual cytocidal effect. Accumulating evidence now implicates the nonstructural (NS1) protein of the virus in cytotoxicity, but the mechanism underlying the NS1-induced cell death is not known. Using a stringent regulatory system, we de... |
9525611 | A single amino acid change in the hemagglutinin protein of measles virus determines its ability to bind CD46 and reveals another receptor on marmoset B cells. | This paper provides evidence for a measles virus receptor other than CD46 on transformed marmoset and human B cells. We first showed that most tissues of marmosets are missing the SCR1 domain of CD46, which is essential for the binding of Edmonston measles virus, a laboratory strain that has been propagated in Vero mon... |
9525578 | Modulation of Sp1 phosphorylation by human immunodeficiency virus type 1 Tat. | We previously reported (K. T. Jeang, R. Chun, N. H. Lin, A. Gatignol, C. G. Glabe, and H. Fan, J. Virol. 67: 6224-6233, 1993) that human immunodeficiency virus type 1 (HIV-1) Tat and Sp1 form a protein-protein complex. Here, we have characterized the physical interaction and a functional consequence of Tat-Sp1 contact.... |
9512563 | Intramolecular derivatization of 2'-amino-pyrimidine modified RNA with functional groups that is compatible with re-amplification. | To expand the scope of nucleic acid aptamers as a tool for precise molecular recognition, functional groups that are not naturally present in nucleic acid molecules are desired. For in vitro selection these new functional groups must be compatible with the selection process. The present method allows the introduction o... |
9520280 | Characterisation and promoter analysis of the Arabidopsis gene encoding high-mobility-group protein HMG-I/Y. | The single-copy gene encoding the Arabidopsis HMG-I/Y protein was isolated and characterised. The gene encodes a protein of 204 amino acid residues and contains a single intron of 73 bp. Primer extension analysis indicates that transcription starts 115 bp upstream of the translation start and the leader sequence contai... |
9502832 | Facilitative effects of the ampakine CX516 on short-term memory in rats: correlations with hippocampal neuronal activity. | In the companion article (Hampson et al., 1998), the ampakine CX516 (Cortex Pharmaceuticals) was shown to produce a marked facilitation of performance of a spatial delayed-nonmatch-to-sample (DNMS) task in rats. Injections of the drug before each daily session produced a marked and progressive improvement in performanc... |
9502831 | Facilitative effects of the ampakine CX516 on short-term memory in rats: enhancement of delayed-nonmatch-to-sample performance. | Ampakines are a family of drugs that selectively increase AMPA receptor-gated currents and improve performance on several behavioral tasks. This report describes evidence that ampakines cause a cumulative enhancement of performance in a spatial short-term memory task (Deadwyler et al., 1996). Two groups of rats were tr... |
9502792 | A model neuron with activity-dependent conductances regulated by multiple calcium sensors. | Membrane channels are subject to a wide variety of regulatory mechanisms that can be affected by activity. We present a model of a stomatogastric ganglion (STG) neuron in which several Ca2+-dependent pathways are used to regulate the maximal conductances of membrane currents in an activity-dependent manner. Unlike prev... |
11825370 | [The timing and mode of surgery in patients with severe acute pancreatitis]. | <h4>Objective</h4>To investigate the timing and mode of surgical management in patients with severe acute pancreatitis (SAP).<h4>Method</h4>The timing, mode of operation and mortality were reviewed retrospectively in 50 SAP cases undergoing laparotomy in our hospital from 1985 to 1994.<h4>Result</h4>The overall mortali... |
9876597 | Cyclodextrin solubilization of ETH-615, a zwitterionic drug. | Therapeutic usefulness of many zwitterionic drugs is hampered by their very low aqueous solubility. The purpose of this work was to investigate the effects of cyclodextrins on the solubility of the zwitterionic drug ETH-615, the role that charge might play in the cyclodextrin complexation, and the influence of polymers... |
9741374 | Reduced mortality in association with the acute respiratory distress syndrome (ARDS). | <h4>Background</h4>A study was undertaken to investigate possible reductions in mortality and/or changes in outcome predictive factors in patients with the acute respiratory distress syndrome (ARDS) managed in a single centre.<h4>Methods</h4>The study was a prospective observational cohort study of two patient populati... |
9741923 | Effects of membrane-active agents in gene delivery. | A large variety of membrane-modifying agents have been used for the enhancement of DNA(lipo)polycation complex based gene transfer. The magnitude of improvement depends on the nature of the membrane-modifying agent and the (poly)cationic carrier. Within the lipid-free polymer-based systems (polyfection), ligand-polylys... |
9708335 | Synthesis and adenosine receptor affinity of 7-beta-D-ribofuranosylxanthine. | 7-beta-D-Ribofuranosylxanthine, a previously unreported isomer of xanthosine, was prepared in four steps from 7-benzylxanthine. The procedure, which involves the use of pivaloyloxymethyl groups to protect the xanthine ring, was also applied to preparation of some 1-N-alkyl derivatives of 7-ribosylxanthine. Adenosine re... |
9695746 | Interleukin-6 augments neutrophil cytotoxic potential via selective enhancement of elastase release. | <h4>Background</h4>Interleukin-6 (IL-6) appears to be a reliable marker of disease severity in critically ill patients at risk for inflammatory organ injury such as ARDS and MOF. Debate continues, however, as to whether this pleiotropic cytokine acts principally as a proinflammatory or counterregulatory mediator. Becau... |
9675883 | Identification of elastin peptides with vasorelaxant activity on rat thoracic aorta. | Elastin peptides obtained in vivo from the enzymatic degradation of elastic fibers are present in the circulating human blood. In order to verify the role that these peptides may have in the regulation of the vascular tone, the activity of several peptides identified in the elastolytic digest of human elastin and some ... |
9671574 | Subchronic intravenous toxicity studies with gamma-cyclodextrin in rats. | The toxicity of gamma-cyclodextrin (gamma-CD), a cyclic polymer of 8 alpha-1,4-linked glucopyranosyl units with potential applications in food and pharmaceutical preparations, was examined in two toxicity studies in rats with intravenous administration of gamma-CD for 1 and 3 months, respectively. Each study comprised ... |
9671573 | Subchronic oral toxicity studies with gamma-cyclodextrin in rats. | The toxicity of gamma-cyclodextrin (gamma-CD), a cyclic polymer of eight alpha-1,4-linked glucopyranosyl units with potential applications as a food ingredient, was examined in a 2-week pilot study followed by a 13-week oral toxicity study in Wistar rats. In the 2-week study, the test substance was administered to grou... |
9671572 | Embryotoxicity and teratogenicity study with gamma-cyclodextrin in rabbits. | In a standard embryotoxicity/teratogenicity study, gamma-cyclodextrin (gamma-CD) was administered to groups of 16, artificially inseminated New Zealand White rabbits at dietary concentrations of 0, 5, 10, or 20%. A comparison group received a diet containing 20% lactose. Treatment started on day 0 of gestation and ende... |
9671571 | Embryotoxicity and teratogenicity study with gamma-cyclodextrin in rats. | The embryotoxicity/teratogenicity of gamma-cyclodextrin (gamma-CD) was examined in Wistar Crl:(WI)WU BR rats. gamma-CD was fed at dietary concentrations of 0, 1.5, 5, 10, and 20% to groups of 25 pregnant female rats from day 0 to 21 of gestation. A comparison group received a diet with 20% lactose. The additions to the... |
9671570 | Subchronic (13-week) oral toxicity study of gamma-cyclodextrin in dogs. | The oral toxicity of gamma-cyclodextrin (gamma-CD) was examined in a 13-week feeding study in which four groups of four male and four female Beagle dogs received gamma-CD in the diet at concentrations of 0 (control), 5, 10, or 20%. No treatment-related changes were noted in behavior or appearance of the dogs and no mor... |
9671569 | Disposition of [14C]gamma-cyclodextrin in germ-free and conventional rats. | The absorption, disposition, metabolism, and excretion of 14C-labeled gamma-cyclodextrin ([14C]gamma-CD) was examined in four separate experiments with Wistar rats. In experiment 1, [14C]gamma-CD (25 microCi, 600 mg/kg body wt) was administered intravenously to four male and four female conventional rats. In experiment... |
9653972 | Investigation of the stereoselective metabolism of praziquantel after incubation with rat liver microsomes by capillary electrophoresis and liquid chromatography-mass spectrometry. | Two different separation methods for the antischistosomal drug praziquantel and its metabolites by capillary electrophoresis are described. Achiral separation was obtained by micellar electrokinetic capillary chromatography using sodium dodecyl sulfate as micelle-forming surfactant. On the other hand, the negatively ch... |
9653971 | Comparison of chiral recognition capabilities of cyclodextrins for the separation of basic drugs in capillary zone electrophoresis. | The enantiomeric separation of some racemic anti-histamines and anti-malarials, namely (+/-)-pheniramine, (+/-)-brompheniramine, (+/-)-chlorpheniramine, (+/-)-doxylamine, and (+/-)-chloroquine, was investigated by capillary zone electrophoresis. The enantiomeric separation of five compounds was obtained by addition of ... |
9653970 | Determination of flufenamic, meclofenamic and mefenamic acids by capillary electrophoresis using beta-cyclodextrin. | The possibility of separating flufenamic, meclofenamic and mefenamic acids by capillary electrophoresis was studied. The best approach involved combining a suitable pH of the carrier electrolyte (pH 12.0) with the host-guest complexation effects of beta-cyclodextrin. A running buffer consisting of 30 mM phosphate buffe... |
9653941 | Modified cyclodextrins as chiral selectors: molecular modelling investigations on the enantioselective binding properties of heptakis(2,3-di-O-methyl-6-O-tert.-butyldimethylsilyl)-beta-cyclodextri n. | Molecular modelling methods have been used to investigate the enantioselective binding properties of chiral dihydrofuranones on heptakis(2,3-di-O-methyl-6-O-tert.-butyldimethylsilyl)-beta-cyclod extrin in capillary gas chromatography. A conformational analysis of the modified beta-cyclodextrin was performed using annea... |
9648208 | Near UV circular dichroism from biomimetic model compounds define the coordination geometry of vanadate centers in MeVi- and MeADPVi-rabbit myosin subfragment 1 complexes in solution. | The circular dichroism (CD) spectrum was measured from vanadate (Vi) cyclic esters of chiral vicinal diols, hydroxycarboxylates, and cyclodextrines as a function of Vi concentration ([Vi]) and at the lowest energy transitions of the vanadium. At low [Vi] and in the presence of excess vicinal diols, hydroxycarboxylates,... |
9648162 | Multiple organ failure associated with extensive metastatic calcification in a patient with an intermediate state of human T lymphotropic virus type I (HTLV-I) infection: report of an autopsy case. | A patient with an intermediate state of human T lymphotropic virus type I (HTLV-I) infection and in whom autopsy showed multiple organ failure (MOF) associated with extensive metastatic calcification in systemic organs is described. A 56-year-old man presented with signs and symptoms of advanced cardiac insufficiency, ... |
9631287 | Filamentous phage structure, infection and assembly. | The structural model of filamentous phage derived by X-ray fibre diffraction is supported by spectroscopic and genetic experiments. The structure of the receptor-binding domain at the end of the phage and the structure of the phage-coded intracellular DNA-binding protein have been determined at high resolution. The rec... |
9634279 | Capillary electrophoretic and high-performance liquid chromatographic studies of the enantioselective separation of alpha1-adrenoreceptor antagonists. | Capillary electrophoresis (CE) and chiral stationary phase (CSP) HPLC methods were investigated for the determination of enantiomeric purity of alpha1-adrenoreceptor antagonists related to WB 4101. In the CE study, the enantioseparation of the analytes was performed by studying the effect of different types of cyclodex... |
9628369 | Restriction endonucleases can be used to confirm a structure of unusual DNA duplexes. | Cyclic and polycyclic oligonucleotides were synthesized using chemical ligation. Two types of catenanes with one and several intertwinings were produced. The yield of these molecules depended on the ligation conditions and nucleotide sequence of the ligated oligonucleotide and its template. Structure of ligation produc... |
9628317 | Epithelial and fibroblastoid cells contain numerous cell-type specific putative microtubule-regulating proteins, among which are ezrin and fodrin. | Upon cell junction formation, the microtubules of polarizing epithelial cells become reorganized by unknown signaling mechanisms and regulating proteins. Microtubule-associated (MAPs) and other types of proteins are likely to be involved in this process, but most of these are unknown. Such proteins are called here coll... |
9617350 | Epitope blocking: positive and negative effects on the biodistribution of 125I-labeled anti-Tac disulfide-stabilized Fv fragment of two antibodies against different epitopes of the circulating antigen. | Prior in vivo studies using the 125I-labeled anti-Tac disulfide-stabilized variable region fragment (125I-anti-Tac dsFv) of monoclonal antibody in the presence of the circulating soluble alpha subunit of the interleukin-2 receptor (sIL-2R alpha) have shown formation of complexes which interfere with biodistribution. In... |
9606179 | Human lung surfactant protein A exists in several different oligomeric states: oligomer size distribution varies between patient groups. | <h4>Background</h4>Lung surfactant protein A (SP-A) is a complex molecule composed of up to 18 polypeptide chains. In vivo, SP-A probably binds to a wide range of inhaled materials via the interaction of surface carbohydrates with the lectin domains of SP-A and mediates their interaction with cells as part of a natural... |
9616039 | Determination of chiral catabolites from S-[2-carboxyl-1-(1H-imidazol-4-yl)ethyl]glutathione, a proposed metabolite of L-histidine, by capillary electrophoresis]. | A new method for simultaneous determination of two diastereomers in each of S-[2-carboxy-1-(1H-imidazol-4-yl)ethyl]-L-cysteine (I) and N-¿S-[2-carboxy-1-(1H-imidazol-4-yl)ethyl]-L-cysteinyl¿glycine (II) was developed by electrophoresis using a neutral coated capillary with a separation buffer, pH 6.00, containing 80 mM... |
9613209 | [Thoracic trauma]. | Blunt chest trauma is the leading cause of thoracic injuries in Germany, penetrating chest injuries are rare. Hereby, single or multiple rib fractures, hemato-pneumothorax and pulmonary contusion represent the most common injuries. The early management of thoracic injuries consists of detection and sufficient therapy o... |
9613961 | Enantiomeric separation of tramadol hydrochloride and its metabolites by cyclodextrin-mediated capillary zone electrophoresis. | The enantiomeric separation of tramadol hydrochloride and its major metabolites, O-demethyltramadol (M1) and N-demethyltramadol (M2) was studied using cyclodextrin (CD)-mediated capillary zone electrophoresis (CZE). Influence of the choice of type and concentration of CD, capillary temperature, length of capillaries, b... |
9613957 | Development of a capillary electrophoretic separation of an N-(substituted)-glycine-peptoid combinatorial mixture. | Capillary electrophoresis was used for the separation of a combinatorially synthesized N-(substituted)-glycine (NSG) peptoid mixture. This mixture consisted of 24 trimeric compounds sharing a common backbone structure but differing in the side chain attached at the N-terminal residue. Standards of the individual compon... |
9609666 | Molecular-cytogenetic characterization of the Vicia faba genome--heterochromatin differentiation, replication patterns and sequence localization. | A comprehensive survey of the molecular-cytogenetic features of the Vicia faba chromosome complement (2n = 12) is given. It includes previous as well as new original data. Various Giemsa, restriction endonuclease and fluorochrome banding patterns, azacytidine-mediated segment extension, replication patterns, lateral A/... |
9609665 | Microdissected bovine X chromosome segment delineates homoeologous chromosomal regions in sheep, goat and buffalo. | The terminal part of the long arm of the bovine X chromosome (bands Xq41-q43) was microdissected. The DNA thus obtained was PCR amplified, labelled and used as painting probe on cattle, sheep, goat and buffalo chromosomes. In cattle, as expected, distinct hybridization signals were observed on bands Xq41-q43. In sheep ... |
9609664 | Molecular cytogenetic analysis of heterochromatin in the chromosomes of tilapia, Oreochromis niloticus (Teleostei: Cichlidae). | The structure of the heterochromatic bands in mitotic chromosomes of the important tropical aquaculture species of tilapia, Oreochromis niloticus, was investigated by the combination of the C-banding technique, chromosomal digestion with two restriction endonucleases and fluorescence in situ hybridization (FISH) of two... |
9609663 | Localization of the human membrane-type 2 matrix metalloproteinase gene (MMP15) to 16q12.1 near DNA elements that are part of centromeric and non-centromeric heterochromatin of 11 human chromosomes. | We have localized a second gene for membrane-type matrix metalloproteinases, MT2-MMP, to chromosome 16q12 by in situ hybridization. FISH experiments using a genomic PAC clone containing the MT2-MMP gene resulted in an unusual hybridization pattern detecting centromeric and non-centromeric heterochromatin regions or its... |
9609662 | Tandem duplication of nucleolus organizer region (NOR) in the Japanese macaque, Macaca fuscata fuscata. | During exploration of chromosome polymorphisms in Japanese macaques, a heteromorphic polymorphism was found in a population in the Zigokudani monkey park. The population consisted of three troops (social units). Of 36 monkeys examined, five females showed heterozygotic 'marker' chromosome (chromosome 9). The polymorphi... |
9609661 | Molecular cytogenetic characterization of Thinopyrum and wheat-Thinopyrum translocated chromosomes in a wheat-Thinopyrum amphiploid. | The wheat-Thinopyrum amphiploid 'Agrotriticum # 3425' (AT 3425), which is highly resistant to Cephalosporium stripe, was identified to carry seven pairs of Thinopyrum chromosomes, three pairs of wheat-Thinopyrum translocated chromosomes and 18 pairs of wheat chromosomes. Fluorescence genomic in situ hybridization (FGIS... |
9609660 | Orientation of the 'stretched' univalent X chromosome during the unequal first meiotic division in male aphids. | In situ hybridization was used to label the ends of the X chromosomes of two aphid species, Myzus persicae and Amphorophora tuberculata, in order to study the peculiar behaviour and orientation of the univalent X in aphid spermatogenesis. Anaphase I begins with the long axis of the X chromosome at right angles to the s... |
9609659 | A 169-base pair tandem repeat DNA marker for subtelomeric heterochromatin and chromosomal rearrangements in aphids of the Myzus persicae group. | Numerous copies of a 169-base pair DNA sequence (Myzus persicae group repeat; MpR) occur at subtelomeric locations on all chromosomes of three members of the Myzus persicae species group (Myzus persicae, M. antirrhinii, M. certus). MpR occurs in large tandem arrays at both ends of all autosomes of the standard 2n = 12 ... |
9609658 | DNA methylation of the extraembryonic tissues: an in situ study on human metaphase chromosomes. | DNA methylation level and pattern of human metaphase chromosomes from extraembryonic tissues (chorionic villi and placental fibroblasts) were analysed in situ. The DNA methylation global level of these tissues was studied by comparing them with the one observed in fetal fibroblasts and adult lymphocytes. In order to as... |
9609657 | Evidence for close contact between recombination nodules and the central element of the synaptonemal complex. | During the first part of meiosis, homologous chromosomes pair and undergo genetic recombination. Two meiotic structures are involved in these processes: the synaptonemal complex (SC) is essential for synapsis of the chromosomes, and the recombination nodules (RNs) represent the sites for recombination. In the present i... |
9604336 | Cationic beta-cyclodextrin derivative for chiral separations. | A novel hepta-substituted beta-cyclodextrin bearing the methoxyethylamine group linked to the upper cyclodextrin rim was successfully used as a chiral selector for enantiomeric separation of non-steroidal anti-inflammatory drugs (NSAIDs) and phenoxypropionic acid herbicides (PPAHs). Separation parameters such as pH and... |
9604334 | Separation of polycyclic aromatic hydrocarbon metabolites by gamma-cyclodextrin-modified micellar electrokinetic chromatography with laser-induced fluorescence detection. | Using a modified micellar buffer consisting of gamma-cyclodextrin (gamma-CD) and sodium dodecyl sulfate (SDS), we have obtained separations of hydroxy-polycyclic aromatic hydrocarbons (hydroxyPAHs). These compounds are oxidative products of mammalian PAH metabolism. The analytes were detected with a commercial laser-in... |
9599728 | Animal models of human response to dioxins. | 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is the most potent member of a class of chlorinated hydrocarbons that interact with the aryl hydrocarbon receptor (AhR). TCDD and dioxinlike compounds are environmentally and biologically stable and as a result, human exposure is chronic and widespread. Studies of highly expos... |
9598995 | Rapid and discrete isolation of oxygen-evolving His-tagged photosystem II core complex from Chlamydomonas reinhardtii by Ni2+ affinity column chromatography. | We have developed a simple and rapid procedure to isolate an oxygen-evolving photosystem II (PS II) core complex from Chlamydomonas reinhardtii. A His-tag made of six consecutive histidine residues was genetically attached at the carboxy terminus of D2 protein to create a metal binding site on the PS II supramolecular ... |
9596554 | Neurotoxicity of cholesterol oxides on cultured cerebellar granule cells. | Cultured rat cerebellar granule cells were used to determine the potential neurotoxicity of cholesterol oxides. The cholesterol oxides tested included: 7-beta-OH-, 7-keto-, 19-OH-, 22(R)-OH-, 22(S)-OH- and 25-OH- cholesterol. Among them, 7-beta-OH- and 7-keto-cholesterol were the most efficacious in causing neuronal de... |
9588189 | Bactericidal domain of lactoferrin: detection, quantitation, and characterization of lactoferricin in serum by SELDI affinity mass spectrometry. | Lactoferricin is a bioactive peptide fragment (3196 Da) derived from lactoferrin (80 kDa) that contains the bactericidal domain and the lymphocyte receptor-binding domain of lactoferrin. Although lactoferricin has been produced from lactoferrin by proteolytic digestion in vitro, its natural occurrence and distribution ... |
9588175 | Compartmentalization of phosphatidylinositol 4,5-bisphosphate in low-density membrane domains in the absence of caveolin. | In cells that exhibit caveolae, the hormone-sensitive pool of PtdIns 4,5-P2 is localized in a low density, caveolin-enriched membrane fraction (1). Neuro 2a cells do not express caveolin. Nonetheless, the PtdIns 4,5-P2 in these cells is compartmentalized in a low density, detergent-insoluble domain that also contains o... |
9586631 | Two human T cell receptors bind in a similar diagonal mode to the HLA-A2/Tax peptide complex using different TCR amino acids. | The three-dimensional structure of a human alphabeta T cell receptor (TCR), B7, bound to the HLA-A2 molecule/HTLV-1 Tax peptide complex was determined by x-ray crystallography. Although different from the A6 TCR, previously studied, in 16 of the 17 residues that contact HLA-A2/Tax, the B7 TCR binds in a similar diagona... |
9560399 | Second-site noncomplementation identifies genomic regions required for Drosophila nonmuscle myosin function during morphogenesis. | Drosophila is an ideal metazoan model system for analyzing the role of nonmuscle myosin-II (henceforth, myosin) during development. In Drosophila, myosin function is required for cytokinesis and morphogenesis driven by cell migration and/or cell shape changes during oogenesis, embryogenesis, larval development and pupa... |
9571029 | Sedimentation and electrophoretic migration of DNA knots and catenanes. | Various site-specific recombination enzymes produce different types of knots or catenanes while acting on circular DNA in vitro and in vivo. By analysing the types of knots or links produced, it is possible to reconstruct the order of events during the reaction and to deduce the molecular "architecture" of the complexe... |
9578484 | Molecular and enzymatic characterization of a maltogenic amylase that hydrolyzes and transglycosylates acarbose. | A gene encoding a maltogenic amylase of Bacillus stearothermophilus ET1 was cloned and expressed in Escherichia coli. DNA sequence analysis indicated that the gene could encode a 69,627-Da protein containing 590 amino acids. The predicted amino acid sequence of the enzyme shared 47-70% identity with the sequences of ma... |
9575950 | Neurosteroid modulation of arterial baroreflex-sensitive neurons in rat rostral ventrolateral medulla. | The major metabolite of progesterone, 3 alpha-OH-dihydroprogesterone (3 alpha-OH-DHP), is the most potent endogenous positive modulator of central nervous system GABAA receptors. Acute intravenous administration of 3 alpha-OH-DHP to virgin female rats potentiates arterial baroreflex sympathoinhibitory responses. The cu... |
9568892 | Thermodynamic and structural consequences of flexible loop deletion by circular permutation in the streptavidin-biotin system. | A circularly permuted streptavidin (CP51/46) has been designed to remove the flexible polypeptide loop that undergoes an open to closed conformational change when biotin is bound. The original termini have been joined by a tetrapeptide linker, and four loop residues have been removed, resulting in the creation of new N... |
9560264 | Lipophilic siderophores of Mycobacterium tuberculosis prevent cardiac reperfusion injury. | Reperfusion injury, which occurs upon the reintroduction of blood flow to an ischemic organ, is responsible for considerable damage in heart attacks and strokes. However, no treatment for reperfusion injury is currently available. A major cause of reperfusion injury is the iron-mediated generation of hydroxyl radical (... |
9560203 | Acetylation at Lys-92 enhances signaling by the chemotaxis response regulator protein CheY. | When Escherichia coli cells lacking all chemotaxis proteins except the response regulator CheY are exposed to acetate, clockwise flagellar rotation results, indicating the acetate stimulus has activated signaling by CheY. Acetate can be converted to acetyl-CoA by either of two different metabolic pathways, which procee... |
9558324 | Structure of cyclodextrin glycosyltransferase complexed with a derivative of its main product beta-cyclodextrin. | Crystals of the inactive mutant Glu257-->Ala of cyclodextrin glycosyltransferase were soaked with the cyclodextrin (CD) derivative S-(alpha-D-glucopyranosyl)-6-thio-beta-CD. The structural analysis showed its beta-CD moiety with no density indication for the exocyclic glucosyl unit. For steric reasons, however, the pos... |
9558320 | Thermodynamics of bovine spleen galectin-1 binding to disaccharides: correlation with structure and its effect on oligomerization at the denaturation temperature. | Isothermal titration calorimetry (ITC) measurements of the binding 1-beta carbohydrate-substituted galactopyranoside derivatives to galectin-1 from bovine spleen, a dimer with one binding site per subunit, were performed at 283-285 and 298 K. The disaccharides were lactose, methyl beta-lactoside, lactulose, 4-O-beta-D-... |
9566506 | Neurotoxicity of 25-OH-cholesterol on sympathetic neurons. | Cultured rat sympathetic neurons derived from postnatal rat superior cervical ganglia (SCG) were used to compare the neurotoxicity of several cholesterol oxides. The cholesterol oxides tested included: 7-beta-OH-, 7-keto-, 19-OH-, 22(R)-OH-, 22(S)-OH-, and 25-OH-cholesterol. These agents caused an acute as well as a de... |
9564566 | Use of enzyme tests in characterization and identification of aerobic and facultatively anaerobic gram-positive cocci. | The contribution of enzyme tests to the accurate and rapid routine identification of gram-positive cocci is introduced. The current taxonomy of the genera of aerobic and facultatively anaerobic cocci based on genotypic and phenotypic characterization is reviewed. The clinical and economic importance of members of these... |
9556524 | Artificial chaperone-assisted refolding of proteins. | A new two-step procedure of protein refolding in vitro, proposed by Rozema and Gellman and named artificial chaperone-assisted refolding, is discussed. The new approach has been inspired by the two-step mechanism of the GroE system. In the first step, the protein is captured by a detergent under conditions that would n... |
9556522 | Chaperones in bacteriophage T4 assembly. | Protein folding in the cell is controlled at the levels of translation and post-translational modification, depends on a number of conserved proteins known as chaperones, and is catalyzed by specific enzymes, such as protein disulfide isomerase and peptidyl prolyl cis-trans isomerase. The chaperones stabilize folding i... |
9554879 | Human P2Y1 receptor: molecular modeling and site-directed mutagenesis as tools to identify agonist and antagonist recognition sites. | The molecular basis for recognition by human P2Y1 receptors of the novel, competitive antagonist 2'-deoxy-N6-methyladenosine 3', 5'-bisphosphate (MRS 2179) was probed using site-directed mutagenesis and molecular modeling. The potency of this antagonist was measured in mutant receptors in which key residues in the tran... |
9554877 | Development of a three-dimensional CysLT1 (LTD4) antagonist model with an incorporated amino acid residue from the receptor. | This paper describes the molecular modeling of leukotriene CysLT1 (or LTD4) receptor antagonists. Several different structural classes of CysLT1 antagonists were superimposed onto the new and highly rigid CysLT1 antagonist 8-carboxy-3'-[2-(2-quinolinyl)ethenyl]flavone (1, VUF 5017) to generate a common pharmacophoric a... |
9554854 | Supramolecular structure of the Salmonella typhimurium type III protein secretion system. | The type III secretion system of Salmonella typhimurium directs the translocation of proteins into host cells. Evolutionarily related to the flagellar assembly machinery, this system is also present in other pathogenic bacteria, but its organization is unknown. Electron microscopy revealed supramolecular structures spa... |
9553076 | The N terminus of eukaryotic translation elongation factor 3 interacts with 18 S rRNA and 80 S ribosomes. | Elongation factor-3 (EF-3) is an essential fungal-specific translation factor which exhibits a strong ribosome-dependent ATPase activity and has sequence homologies that may predict domains critical for its role in protein synthesis, including a domain at the N terminus, which exhibits sequence homology with Escherichi... |
9548907 | Inclusion complexation of propofol with 2-hydroxypropyl-beta-cyclodextrin. Physicochemical, nuclear magnetic resonance spectroscopic studies, and anesthetic properties in rat. trapani@ippo.uniba.it. | An aqueous formulations of propofol 1 can be prepared by solubilizing it in the presence of 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CD). This is potentially useful for parenteral administration of the drug. The aqueous solubility of 1 linearly increased as a function of HP-beta-CD concentration and showed features o... |
9548893 | Preparation, characterization, and evaluation of miconazole-cyclodextrin complexes for improved oral and topical delivery. | The solubility of miconazole in water increased in the presence of cyclodextrins (CDs). The apparent K1:1 values calculated from the phase solubility diagrams of gamma-CD, hydroxypropyl-beta-CD, alpha-CD, hydroxyethyl-beta-CD, hydroxypropyl-gamma-CD, and beta-CD were 695 +/- 39.6, 363 +/- 34.1, 333 +/- 18.5, 312 +/- 31... |
9559805 | Pharmacokinetics of two multiple-dosing regimens of D0870 in human immunodeficiency virus-positive patients: a phase I study. | D0870 is a triazole with a broad antifungal spectrum, and it has been shown to have both in vitro and in vivo activities against wild-type and fluconazole-resistant strains of Candida albicans. Twenty-two human immunodeficiency virus (HIV)-positive male subjects were enrolled in an open, nonrandomized trial investigati... |
9559786 | Generation and characterization of a mutant of influenza A virus selected with the neuraminidase inhibitor BCX-140. | Influenza neuraminidase (NA) plays an important role in viral replication, and characterization of viruses resistant to NA inhibitors will help elucidate the role of active-site residues. This information will assist in designing better inhibitors targeted to essential active-site residues that cannot generate drug-res... |
9548956 | Self-association of disulfide-dimerized melittin analogues. | Two cysteine substitutions of bee venom melittin have been synthesized to investigate the effects of disulfide cross-linking on the self-association properties of the peptide in solution. K23C melittin (mltK23C) was designed to link nonpolar surfaces of the amphipathic melittin helix on the basis of the close juxtaposi... |
9548730 | Rho-mediated contractility exposes a cryptic site in fibronectin and induces fibronectin matrix assembly. | Many factors influence the assembly of fibronectin into an insoluble fibrillar extracellular matrix. Previous work demonstrated that one component in serum that promotes the assembly of fibronectin is lysophosphatidic acid (Zhang, Q., W.J. Checovich, D.M. Peters, R.M. Albrecht, and D.F. Mosher. 1994. J. Cell Biol. 127:... |
9548742 | Protein-induced changes in nonplanarity of the porphyrin in nickel cytochrome c probed by resonance Raman spectroscopy. | The influence of the protein on the nonplanarity of the macrocycle for nickel(II)-reconstituted cytochrome c (NiCyt-c) has been investigated with pH-dependent resonance Raman and UV-visible absorption spectroscopy and molecular mechanics calculations. The spectra reveal that NiCyt-c near neutral pH has axially coordina... |
9553497 | Capillary zone electrophoresis of bile acids with indirect photometric detection. | Investigations in our laboratory have demonstrated that capillary zone electrophoresis (CZE) with indirect photometric detection is a viable approach to the separation and identification of free bile acids along with their taurine and glycine derivatives. Various parameters such as pH, organic solvent concentrations, c... |
9554489 | Reference standardization and triglyceride interference of a new homogeneous HDL-cholesterol assay compared with a former chemical precipitation assay. | A homogeneous HDL-c assay (HDL-H), which uses polyethylene glycol-modified enzymes and sulfated alpha-cyclodextrin, was assessed for precision, accuracy, and cholesterol and triglyceride interference. In addition, its analytical performance was compared with that of a phosphotungstic acid (PTA)/MgCl2 precipitation meth... |
9545249 | Tertiary structure formation in the hairpin ribozyme monitored by fluorescence resonance energy transfer. | The complex formed by the hairpin ribozyme and its substrate consists of two independently folding domains which interact to form a catalytic structure. Fluorescence resonance energy transfer methods permit us to study reversible transitions of the complex between open and closed forms. Results indicate that docking of... |
9545231 | Ramifications of kinetic partitioning on usher-mediated pilus biogenesis. | The biogenesis of diverse adhesive structures in a variety of Gram-negative bacterial species is dependent on the chaperone/usher pathway. Very little is known about how the usher protein translocates protein subunits across the outer membrane or how assembly of these adhesive structures occurs. We have discovered seve... |
9541490 | Helicobacter pylori upregulates expression of epidermal growth factor-related peptides, but inhibits their proliferative effect in MKN 28 gastric mucosal cells. | Acute exposure to Helicobacter pylori causes cell damage and impairs the processes of cell migration and proliferation in cultured gastric mucosal cells in vitro. EGF-related growth factors play a major role in protecting gastric mucosa against injury, and are involved in the process of gastric mucosal healing. We ther... |
9539732 | Sequence-specific polypeptoids: a diverse family of heteropolymers with stable secondary structure. | We have synthesized and characterized a family of structured oligo-N-substituted-glycines (peptoids) up to 36 residues in length by using an efficient solid-phase protocol to incorporate chemically diverse side chains in a sequence-specific fashion. We investigated polypeptoids containing side chains with a chiral cent... |
9539701 | Plant terpenoid synthases: molecular biology and phylogenetic analysis. | This review focuses on the monoterpene, sesquiterpene, and diterpene synthases of plant origin that use the corresponding C10, C15, and C20 prenyl diphosphates as substrates to generate the enormous diversity of carbon skeletons characteristic of the terpenoid family of natural products. A description of the enzymology... |
9535977 | L-Type calcium channels are required for one form of hippocampal mossy fiber LTP. | The requirement of postsynaptic calcium influx via L-type channels for the induction of long-term potentiation (LTP) of mossy fiber input to CA3 pyramidal neurons was tested for two different patterns of stimulation. Two types of LTP-inducing stimuli were used based on the suggestion that one of them, brief high-freque... |
9535854 | Glomerular basement membrane. Identification of a novel disulfide-cross-linked network of alpha3, alpha4, and alpha5 chains of type IV collagen and its implications for the pathogenesis of Alport syndrome. | Glomerular basement membrane (GBM) plays a crucial function in the ultrafiltration of blood plasma by the kidney. This function is impaired in Alport syndrome, a hereditary disorder that is caused by mutations in the gene encoding type IV collagen, but it is not known how the mutations lead to a defective GBM. In the p... |
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