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8581303 | Molecular characterization of a centromeric satellite DNA in the hemiclonal hybrid frog Rana esculenta and its parental species. | Hybrid water frogs Rana esculenta reproduce by hybridogenesis: one parental genome (of Rana lessonae) is excluded in the germ line, the other (of Rana ridibunda) is clonally transmitted to haploid gametes. The two parental species differ in that the amount of centromeric heterochromatin revealed by differential stainin... |
8581302 | Reprogramming of rye rDNA in triticale during microsporogenesis. | To test the hypothesis that interspecific genomic and chromosome interactions leading to nucleolar dominance could be reprogrammed in meiosis, we compared the expression of distinct nucleolar organizing region (NOR) loci in hexaploid triticale root tip meristematic cells, pollen mother cells and young pollen grains. In... |
8581301 | The influence of B chromosomes on rDNA organization in rye interphase nuclei. | Patterns of rye rDNA organization in interphase nuclei were studied through the use of in situ hybridization in spreads of root meristem cells from plants with and without B chromosomes (Bs). In cells from plants without Bs each rDNA locus is organized as a single perinucleolar knob of condensed chromatin with deconden... |
8581300 | ZOO-FISH analysis: cat and human karyotypes closely resemble the putative ancestral mammalian karyotype. | DNA in situ hybridization with human chromosome specific DNA libraries was applied to compare the karyotypes of humans (Homo sapiens, 2n = 46) and cats (Felis catus, 2n = 38). For the autosomes alone, 30 segments of conserved synteny were revealed. The arrangement of these segments in the feline karyotype differs by on... |
8581299 | Mapping of murine YACs containing the genes Cea2 and Cea4 after B1-PCR amplification and FISH-analysis. | PCR with primers specific for the murine B1 consensus sequence allows amplification of DNA from murine sources. We have used B1-PCR for amplifying yeast artificial chromosome (YAC) DNA which can be used to localize single YACs by fluorescence in situ hybridization. The genes for the pregnancy-specific glycoproteins Cea... |
8581298 | Analysis of rye B-chromosome structure using fluorescence in situ hybridization (FISH). | Fluorescence in situ hybridization (FISH) has been used to analyse the structure of the rye B chromosome. Genomic in situ hybridization (GISH) demonstrates the high level of overall similarity between A and B chromosomes of rye, as well as the presence of a number of specific sequences. The B-specific repeat families D... |
8581297 | Impact of rearrangements on function and position of chromosomes in the interphase nucleus and on human genetic disorders. | A synthesis of numerous published data and my own observations reveal that chromatin structure in interphase is functional, dynamic and complex. I hypothesize that: (1) chromosome regions organize nuclear structures and thus their own environment (address themselves in sites and condensation patterns most appropriate f... |
8527433 | Backbone dynamics of the A-domain of HMG1 as studied by 15N NMR spectroscopy. | The HMG-box sequence motif (approximately 80 residues) occurs in a number of abundant eukaryotic chromosomal proteins such as HMG1, which binds DNA without sequence specificity, but with "structure specificity", as well as in several sequence-specific transcription factors. HMG1 has two such boxes, A and B, which show ... |
8527432 | Structure of the A-domain of HMG1 and its interaction with DNA as studied by heteronuclear three- and four-dimensional NMR spectroscopy. | HMG1 has two homologous, folded DNA-binding domains ("HMG boxes"), A and B, linked by a short basic region to an acidic C-terminal domain. Like the whole protein, which may perform an architectural role in chromatin, the individual boxes bind to DNA without sequence specificity, have a preference for distorted or prebe... |
8527431 | 2 A resolution structure of DppA, a periplasmic dipeptide transport/chemosensory receptor. | The family of about 50 periplasmic binding proteins, which exhibit diverse specificity (e.g., carbohydrates, amino acids, dipeptides, oligopeptides, oxyanions, metals, and vitamins) and range in size from 20 to 58 kDa, is a gold mine for an atomic-level investigation of structure and molecular recognition. These protei... |
8531885 | Genetic elements of plant viruses as tools for genetic engineering. | Viruses have developed successful strategies for propagation at the expense of their host cells. Efficient gene expression, genome multiplication, and invasion of the host are enabled by virus-encoded genetic elements, many of which are well characterized. Sequences derived from plant DNA and RNA viruses can be used to... |
8579751 | Molecular recognition of antigen involves lattice formation between CD4, MHC class II and TCR molecules. | Recent evidence indicates that CD4 stably binds to major histocompatibility complex (MHC) class II only after assuming an oligomeric state: the membrane-distal CD4 D1-D2 module interacts directly with MHC class II, whereas the membrane-proximal CD4 D3-D4 module mediates oligomerization. This results in the formation of... |
8846773 | Identification of two novel arginine binding DNAs. | RNA tertiary structure is known to play critical roles in RNA-protein recognition and RNA function. To examine how DNA tertiary structure might relate to RNA structure, we performed in vitro selection experiments to identify single-stranded DNAs that specifically bind arginine, and compared the results with analogous e... |
8634069 | Gamete and immune cell recognition revisited. | Fertilization is the result of a series of successful recognition and binding events mediated by gamete surface molecules. Recent advances in the identification and characterization of some of these recognition molecules provide extremely valuable information necessary to understand sperm-egg recognition and subsequent... |
8849334 | The effect of crown ethers, tetraalkylammonium salts, and polyoxyethylene amphiphiles on pirarubicin incorporation in K562 resistant cells. | The basic distinguishing feature of all cells expressing functional P-glycoprotein-multidrug resistance (P-gp-MDR) is a decrease in steady-state accumulation drug levels as compared to drug-sensitive controls. In an attempt to identify mechanism(s) by which MDR can be circumvented, we examined the cellular accumulation... |
8848012 | 125I-4-(2-[7-amino-2-[2-furyl][1,2,4]triazolo[2,3-a][1,3,5] triazin-5-yl-amino]ethyl)phenol, a high affinity antagonist radioligand selective for the A2a adenosine receptor. | The A2a adenosine receptor (AR) mediates several important physiological effects of adenosine, including vasodilation and inhibition of platelet aggregation. Until recently, no antagonist radioligand of sufficient selectivity or affinity was available. We describe the synthesis and characterization by radioligand bindi... |
8845371 | Residues in the fifth membrane-spanning segment of the dopamine D2 receptor exposed in the binding-site crevice. | The binding site of the dopamine D2 receptor, like that of other homologous G-protein-coupled receptors, is contained within a water-accessible crevice formed among its seven membrane-spanning segments. Using the substituted-cysteine accessibility method, we previously mapped the residues in the third membrane-spanning... |
8845367 | Gramicidin channel function does not depend on phospholipid chirality. | Chiral interactions are often important determinants for molecular recognition in chemistry and biochemistry. In order to determine whether the phospholipid backbone could be important for the conformational preference of membrane-spanning channels, we made use of the linear pentadecapeptide antibiotic gramicidin A (gA... |
8618910 | Synthesis and assembly of self-complementary calix[4]arenes. | A calix[4]arene was designed to reversibly dimerize and form an egg-shaped enclosure. Adhesive interactions in the assembly were provided by four self-associating ureas, which form a cyclic array containing 16 hydrogen bonds. The synthesis was completed in four steps from the previously described O,O',O",O"'-tetrabenzy... |
8618877 | The stem cell antigen CD34 functions as a regulator of hemopoietic cell adhesion. | Although the CD34 antigen is widely used in the identification and purification of hemopoietic stem and progenitor cells, its function within hemopoiesis is unknown. We have investigated this issue by ectopically expressing human (hu) CD34 on the surface of murine hemopoietic cells. Forced expression of hu-CD34 in the ... |
8618858 | Interaction between the phage HK022 Nun protein and the nut RNA of phage lambda. | The nun gene product of prophage HK022 excludes phage lambda infection by blocking the expression of genes downstream from the lambda nut sequence. The Nun protein functions both by competing with lambda N transcription-antitermination protein and by actively inducing transcription termination on the lambda chromosome.... |
8618834 | Synthesis and coupling reactions of alpha,alpha-dialkylated amino acids with nucleobase side chains. | Several di- and tripeptides containing protected purine (adenine) and pyrimidine (thymine) residues on their side chains were synthesized. The parent amino acids alpha, alpha-dialkylated in a symmetrical manner. An effective coupling procedure was developed for these sterically hindered amino acids: the fluoren-9-ylmet... |
8613739 | Facilitation of olfactory learning by a modulator of AMPA receptors. | The effects of a benzoyl-piperidine drug (BDP) that facilitates AMPA receptor-mediated synaptic responses were tested on the acquisition and retention of long-term memory at dosages that had no detectable effects on a variety of performance measures. BDP-12 produced a dose-dependent suppression of exploratory activity ... |
8526866 | Altering kinetic mechanism and enzyme stability by mutagenesis of the dimer interface of glutathione reductase. | In wild-type glutathione reductase from Escherichia coli residues Val421 and Ala422 are located in an alpha-helix in a densely packed and hydrophobic region of the dimer interface, with their side chains packed against those of residues Ala422' and Val421' in the second subunit. A series of mutant glutathione reductase... |
8519660 | Pharmacokinetics and binding of the bioreductive probe for hypoxia, NITP: effect of route of administration. | The novel compound 7(-)[4'-(2-nitroimidazol-l-yl)-butyl]-theophylline (NITP) can be used as an immunologically detectable probe for hypoxic cells. Because of the limited water solubility of NITP, it has been administered dissolved in peanut oil with 10% dimethylsulphoxide (DMSO). A new aqueous formulation has been devi... |
8519646 | Preparation and preclinical evaluation of humanised A33 immunoconjugates for radioimmunotherapy. | A humanised IgG1/k version of A33 (hA33) has been constructed and expressed with yields up to 700 mg l-1 in mouse myeloma NS0 cells in suspension culture. The equilibrium dissociation constant of hA33 (KD = 1.3 nM) was shown to be equivalent to that of the murine antibody in a cell-binding assay. hA33 labelled with ytt... |
8524863 | Analysis of RNA-binding proteins by in vitro genetic selection: identification of an amino acid residue important for locking U1A onto its RNA target. | An in vitro genetic system was developed as a rapid means for studying the specificity determinants of RNA-binding proteins. This system was used to investigate the origin of the RNA-binding specificity of the mammalian spliceosomal protein U1A. The U1A domain responsible for binding to U1 small nuclear RNA was locally... |
8524852 | Topoisomerase IV is a target of quinolones in Escherichia coli. | We have demonstrated that, in Escherichia coli, quinolone antimicrobial agents target topoisomerase IV (topo IV). The inhibition of topo IV becomes apparent only when gyrase is mutated to quinolone resistance. In such mutants, these antibiotics caused accumulation of replication catenanes, which is diagnostic of a loss... |
8524836 | Crystal structure of the complex of a catalytic antibody Fab fragment with a transition state analog: structural similarities in esterase-like catalytic antibodies. | The x-ray structure of the complex of a catalytic antibody Fab fragment with a phosphonate transition-state analog has been determined. The antibody (CNJ206) catalyzes the hydrolysis of p-nitrophenyl esters with significant rate enhancement and substrate specificity. Comparison of this structure with that of the uncomp... |
8524780 | Uniparental inheritance of mitochondrial and chloroplast genes: mechanisms and evolution. | In nearly all eukaryotes, at least some individuals inherit mitochondrial and chloroplast genes from only one parent. There is no single mechanism of uniparental inheritance: organelle gene inheritance is blocked by a variety of mechanisms and at different stages of reproduction in different species. Frequent changes i... |
8522606 | Ponticulin plays a role in the positional stabilization of pseudopods. | Ponticulin is a 17-kD glycoprotein that represents a major high affinity link between the plasma membrane and the cortical actin network of Dictyostelium. To assess the role of ponticulin in pseudopod extension and retraction, the motile behavior of two independently generated mutants lacking ponticulin was analyzed us... |
8523984 | Morphologic study of the laryngeal taste buds in the cat. | The distribution of laryngeal taste buds (TBs) and their neutral components in the cat were investigated by immunohistochemistry and electron microscopy. The antisera used in this study were against cytokeratin, protein gene product 9.5 (PGP9.5), neuron-specific enolase (NSE), S-100 protein, calbindin D, calcitonin gen... |
8519768 | Berenil binding to higher ordered nucleic acid structures: complexation with a DNA and RNA triple helix. | Berenil is an antitrypanosomal agent that binds to nucleic acid duplexes. Recently, we reported that this drug can bind to both DNA and RNA duplexes, while exhibiting properties characteristic of both intercalation and groove binding [Pilch, D. S., Kirolos, M. A., Liu, X., Plum, G. E., & Breslauer, K. J. (1995) Biochem... |
8522527 | Ferrichrome transport in Escherichia coli K-12: altered substrate specificity of mutated periplasmic FhuD and interaction of FhuD with the integral membrane protein FhuB. | FhuD is the periplasmic binding protein of the ferric hydroxamate transport system of Escherichia coli. FhuD was isolated and purified as a His-tag-labeled derivative on a Ni-chelate resin. The dissociation constants for ferric hydroxamates were estimated from the concentration-dependent decrease in the intrinsic fluor... |
8522510 | Mechanics of bacterial macrofiber initiation. | The twisting and writhing during growth of single-cell filaments of Bacillus subtilis which lead to macrofiber formation was studied in both left- and right-handed forms of strains FJ7 and RHX. Filament bending, touching, and loop formation (folding), followed by winding up into a double-strand fiber, were documented. ... |
7490765 | Canonical structure repertoire of the antigen-binding site of immunoglobulins suggests strong geometrical restrictions associated to the mechanism of immune recognition. | Is the structural repertoire of immunoglobulins free to adopt an almost infinite number of conformations to build the diversity of the immune response or does it take advantage of only a few conformations? In this paper we study this question by applying the canonical structure model to characterize the structural repe... |
8525608 | A conserved motif at the 3' end of mouse hepatitis virus genomic RNA required for host protein binding and viral RNA replication. | A conserved 11-nucleotide sequence, UGAAUGAAGUU, at the 3' end of the genomic RNA of coronavirus mouse hepatitis virus was required for host protein binding and viral RNA synthesis. An RNA probe containing this 11-nucleotide sequence bound four cellular proteins with a highly labeled protein of 120 kDa and three minor ... |
7491493 | Autoencapsulation through intermolecular forces: a synthetic self-assembling spherical complex. | The synthesis and characterization of a system for the study of molecular recognition phenomena are described. The system involves a tetraurea molecule that is capable of assembly into various associated states through hydrogen bonding. In organic solvents, the dynamic transition between a low-ordered (aggregate) state... |
8530600 | Pharmacokinetics, bioefficacy, and safety of sublingual testosterone cyclodextrin in hypogonadal men: comparison to testosterone enanthate--a clinical research center study. | We studied and compared the pharmacokinetics and bioefficacy of two doses of sublingual testosterone cyclodextrin (SLT; 2.5 and 5.0 mg, administered three times per day) with testosterone enanthate (TE; 200 mg) given once every 20 days by im injections over a 60-day study period in 63 hypogonadal men. After SLT adminis... |
7493956 | Crystallographic studies of the interaction of cyclodextrin glycosyltransferase from Bacillus circulans strain 251 with natural substrates and products. | Asp-229, Glu-257, and Asp-328 constitute the catalytic residues in cyclodextrin glycosyl transferase from Bacillus circulans strain 251. Via site-directed mutagenesis constructed D229N, E257Q, and D328N mutant proteins showed a 4,000-60,000-fold reduction of cyclization activity. A D229N/E257Q double mutant showed a 70... |
7490300 | Enantiomeric separation of diltiazem, clentiazem, and its related compounds by capillary electrophoresis using polysaccharides. | The direct separation of the enantiomers of diltiazem and its three chloro derivatives, including clentiazem, was investigated by capillary zone electrophoresis (CZE) and electrokinetic chromatography (EKC) using polysaccharides. An electrically neutral beta-cyclodextrin polymer, dextran sulfate, and mucopolysaccharide... |
7494347 | Association of reovirus outer capsid proteins sigma 3 and mu 1 causes a conformational change that renders sigma 3 protease sensitive. | Association of the reovirus proteins sigma 3 and mu 1 influences viral entry, initiation of outer capsid assembly, and modulation of the effect of sigma 3 on cellular translation. In this study, we have addressed whether structural changes occur in sigma 3 as a result of its interaction with mu 1. Using differences in ... |
7494343 | Role of CD4 endocytosis in human immunodeficiency virus infection. | We have analyzed the role of CD4 endocytosis in human immunodeficiency virus (HIV) entry by measuring the infection of HeLa cells expressing various CD4 constructs with endocytosis rates of between 0.2 and 30%/min in a quantitative infectious focus assay. For a number of laboratory-adapted HIV-1 and HIV-2 strains, the ... |
7494316 | In vitro selection of RNA ligands for the ribosomal L22 protein associated with Epstein-Barr virus-expressed RNA by using randomized and cDNA-derived RNA libraries. | The Epstein-Barr virus (EBV)-expressed RNA 1 (EBER1) associates tightly with the ribosomal protein L22. We determined the general requirements for an RNA to bind L22 in a SELEX experiment, selecting RNA ligands for L22 from a randomized pool of RNA sequences by using an L22-glutathione S-transferase fusion protein. The... |
7494309 | Human cytomegalovirus IE1 and IE2 proteins block apoptosis. | Human cytomegalovirus-infected fibroblasts are resistant to the induction of apoptosis by superinfection with a mutant adenovirus unable to produce the viral E1B 19-kDa protein that normally causes an E1A protein-mediated apoptotic response. Two cytomegalovirus gene products that block apoptosis were identified. The IE... |
7494292 | In vivo and in vitro association of hsc70 with polyomavirus capsid proteins. | Members of the 70-kDa family of cellular stress proteins assit in protein folding by preventing inappropriate intra- and intermolecular interactions during normal protein synthesis and transport and when cells are exposed to a variety of environmental stresses. During infection of A31 mouse fibroblasts with polyomaviru... |
7494284 | Human papillomavirus type 16 variant lineages in United States populations characterized by nucleotide sequence analysis of the E6, L2, and L1 coding segments. | Human papillomavirus type 16 (HPV16) nucleotide sequence variations in the E6 (nucleotide positions [nt] 104 to 559), L2 (nt 4272 to 5657), and L1 (nt 5665 to 7148) open reading frames (ORFs), and the long control region (nt 7479 to 7842), were examined in 29 selected United States isolates. Of 3,690 nucleotide positio... |
7494283 | Expression of the polyomavirus minor capsid proteins VP2 and VP3 in Escherichia coli: in vitro interactions with recombinant VP1 capsomeres. | The polyomavirus VP2 and VP3 capsid proteins were expressed in Escherichia coli. The majority of the expressed proteins were in an insoluble fraction, and they were extracted and initially purified in 8 M urea before renaturation. Soluble VP2 and VP3 were mixed with purified recombinant VP1 capsomeres, and their intera... |
7494275 | A mimotope from a solid-phase peptide library induces a measles virus-neutralizing and protective antibody response. | A solid-phase 8-mer random combinatorial peptide library was used to generate a panel of mimotopes of an epitope recognized by a monoclonal antibody to the F protein of measles virus (MV). An inhibition immunoassay was used to show that these peptides were bound by the monoclonal antibody with different affinities. BAL... |
7494269 | Binding of cellular repressor protein or the IE2 protein to a cis-acting negative regulatory element upstream of a human cytomegalovirus early promoter. | We have previously shown that the human cytomegalovirus early UL4 promoter has upstream negative and positive cis-acting regulatory elements. In the absence of the upstream negative regulatory region, the positive element confers strong transcriptional activity. The positive element contains a CCAAT box dyad symmetry a... |
7592471 | Heterologous assembly and rescue of stranded phycocyanin subunits by expression of a foreign cpcBA operon in Synechocystis sp. strain 6803. | Light harvesting in cyanobacteria is performed by the biliproteins, which are organized into membrane-associated complexes called phycobilisomes. Most phycobilisomes have a core substructure that is composed of the allophycocyanin biliproteins and is energetically linked to chlorophyll in the photosynthetic membrane. R... |
8524224 | Context effects on misreading and suppression at UAG codons in human cells. | The effect of the 3' codon context on the efficiency of nonsense suppression in mammalian tissue culture cells has been tested. Measurements were made following the transfection of cells with a pRSVgal reporter vector that contained the classical Escherichia coli lacZ UAG allele YA559. The position of this mutation was... |
8524215 | Association of the viral oncoprotein STP-C488 with cellular ras. | The STP-C488 oncogene of herpesvirus saimiri has transforming activity independent of the rest of the viral genome. We now demonstrate that STP-C488 associates with cellular ras in transformed cells. Mutations that disrupted this association with ras disrupted the transforming ability of the STP-C488 oncogene. Binding ... |
7474121 | Postoligomerization folding of human cytomegalovirus glycoprotein B: identification of folding intermediates and importance of disulfide bonding. | Human cytomegalovirus glycoprotein B (gB or UL55) has been demonstrated to be a disulfide-linked homodimer within the envelope of mature virions. Previously, it has been shown that gB undergoes a rapid dimerization nearly coincident with its synthesis. Following dimerization, the molecule slowly folds into a form which... |
7474083 | Double-stranded RNA bacteriophage phi 6 protein P4 is an unspecific nucleoside triphosphatase activated by calcium ions. | Double-stranded RNA bacteriophage phi 6 has an envelope surrounding the nucleocapsid (NC). The NC is composed of a surface protein, P8, and proteins P1, P2, P4, and P7, which form a dodecahedral polymerase complex enclosing the segmented viral genome. Empty polymerase complex particles (procapsids) package positive-sen... |
8960264 | Inclusion complexes of nifedipine and other 1.4-dihydropyridine derivatives with cyclodextrins. IV. The UV study on photochemical stability of the inclusion complexes of nisoldipine, nimodipine, nitrendipine and nicardipine with beta-cyclodextrin in the solution. | The results of measurements of photochemical stability of the inclusion complexes formed by nimodipine (NM), nisoldipine (NS), nitrendipine (NR) and nicardipine (NC) with beta-cyclodextrin (beta-CD) are reported. The inclusion complexes were obtained in solution. The formation of inclusion complexes in the liquid phase... |
9052977 | Analysis of affinity supports by 13C CP/MAS NMR spectroscopy: application to carbonyldiimidazole- and novel tresyl chloride-synthesized agarose and silica gels. | A major problem in affinity technology is the analysis of the synthesized solid supports, since liquid phase methodology can generally not be applied. Recently we reported a novel reaction sequence for the 2,2,2-trifluoroethanesulfonyl chloride (tresyl chloride) coupling of nucleophiles [Demiroglou et al. (1994) Angew.... |
9052976 | Solution dynamics of the oligosaccharide moiety of ganglioside GM1: comparison of solution conformations with the bound state conformation in association with cholera toxin B-pentamer. | The solution dynamics of the oligosaccharide moiety of ganglioside GM1 have been determined by use of a combination of 1H rotating frame Overhauser effect measurements and restrained molecular dynamics simulations. It is found that the Galbeta1-3 and NeuNAc moieties which are primarily recognized by cholera toxin both ... |
9052975 | Structural requirements for and consequences of an antiviral porphyrin binding to the V3 loop of the human immunodeficiency virus (HIV-1) envelope glycoprotein gp120. | Several porphyrin derivatives were reported to have anti-HIV-1 activity. Among them, meso-teta(4-carboxyphenyl)porphine (MTCPP) and other carboxyphenyl derivatives were the most potent inhibitors (EC50 <0.7 mu M). MTCPP bound to the HIV-1 envelope glycoprotein gp120 and to full-length V3 loop peptides corresponding to ... |
9052974 | Occluded molecular surface: analysis of protein packing. | We describe a novel method to calculate the packing interactions in protein structural models. The method calculates the interatomic occluded surface areas for each atom in the protein model. The identification of, and degree of interaction with, neighboring atoms is accomplished by extending surface normals from a dot... |
9052973 | Metabolic engineering of a non-allosteric citrate synthase in an Escherichia coli citrate synthase mutant. | This study examined the organization of the Krebs tricarboxylic acid (TCA) cycle by metabolic engineering and high-resolution 13C NMR. The oxidation of [1,2,3-13C]propionate to glutamate via the TCA cycle was measured in wild-type (WT) and a citrate synthase mutant (CS-) strain of Escherichia coli transformed with allo... |
8872457 | Modelling the P2Y purinoceptor using rhodopsin as template. | The P2Y1 purinoceptor cloned from chick brain (Webb, T. et al (1993) FEBS Lett., 324, 219-225) is a 362 amino acid, 41 kDa protein. To locate residues tentatively involved in ligand recognition a molecular model of the P2Y purinoceptor has been constructed. The model was based on the primary sequence and structural hom... |
8788139 | Specific and sensitive determination of digoxin and metabolites in human serum by high performance liquid chromatography with cyclodextrin solid-phase extraction and precolumn fluorescence derivatization. | A precolumn fluorescence derivatization high performance liquid chromatographic method has been developed for the simultaneous determination of digoxin and its metabolites digoxigenin bisdigitoxoside, digoxigenin monodigitoxoside digoxigenin, and dihydrodigoxin (20-R and 20-S epimers) in human serum. Digoxin and its me... |
8788133 | Enantiomeric separation of denopamine by capillary electrophoresis and high-performance liquid chromatography using cyclodextrins. | Direct separation of enantiomers of denopamine was investigated by two separation methods. One is capillary zone electrophoresis (CZE) using cyclodextrins (CDs) (CD-CZE) and the other is high-performance liquid chromatography (HPLC) using CD immobilized chiral stationary phases (CD-CSPs). Enantiomers of denopamine were... |
8748745 | Electroosmotic control of chiral separation in capillary zone electrophoresis. | The resolution in capillary zone electrophoresis (CZE), with the assumption of diffusion control only, is strongly dependent on the direction and magnitude of electroosmotic flow. In fact, excellent separation resolution will be obtained if the electroosmotic flow is in the opposite direction of the electrophoretic mig... |
8717184 | [Recent data on the physiopathology of septic shock]. | This review is going on to emphasize recent advances of the pathophysiology of septic shock (SS) which goes-between the systemic inflammatory response syndrome (SIRS) and the multisystem organ failure (MOF). By several recent studies, our knowledge of the cellular and molecular pathophysiology of the SS has dramaticall... |
8703644 | Cardiorespiratory effects of continuous i.v. administration of the ACE inhibitor enalaprilat in the critically ill. | 1. Cardiorespiratory effects of long-term, continuous i.v. administration of the ACE inhibitor enalaprilat were studied. 2. Forty-five consecutive critically patients suffering from trauma or postoperative complications were randomly separated into three groups (15 patients in each group) receiving either 0.25 mg h-1 o... |
8708982 | Effect of 2-hydroxypropyl-beta-cyclodextrin on percutaneous absorption of methyl paraben. | A potential use of 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CyD) to solubilize methyl paraben and to suppress its percutaneous absorption was examined, and compared with nonionic surfactant HCO-60. HP-beta-CyD significantly increased the solubility of methyl paraben in water, where the apparent 1:1 stability constant... |
8647720 | Quantitative evaluation of myelinated nerve fibres and hair cells in cochleae of humans with age-related high-tone hearing loss. | In this study 9 human temporal bones from 8 individuals were fixed with Karnovsky solution by perilymphatic perfusion within 1-3 h after death and examined using the "block-surface method' (Spoendlin and Brun, 1974; Spoendlin and Schrott, 1987) and the "micro-dissection method' (Johnsson and Hawkins, 1967). The audiogr... |
8574600 | The nutritional management of acute renal failure in the intensive care unit. | The nutritional support of patients with acute renal failure (ARF) in the ICU has undergone major changes. Nutritional therapy in these patients should not depend on the impairment of renal function but on the severity of multiple organ failure (MOF). There are no differences in general rules for the nutrition of the c... |
8582450 | Platelet activation and interaction with leucocytes in patients with sepsis or multiple organ failure. | This study focuses on the role of platelet membrane glycoproteins and platelet-leucocyte adhesion in patients with sepsis and multiple organ failure (MOF). Specifically, the study raises the following issues: (1) the influence of sepsis and MOF on platelet activation as assessed by surface expression of platelet membra... |
8580702 | Chiral separation of naphthalene-2,3-dialdehyde labelled peptides by cyclodextrin-modified electrokinetic chromatography. | The chiral separation of several dipeptide enantiomers, derivatized by naphthalene-2,3-dialdehyde (NDA), was achieved by use of cyclodextrin-modified micellar electrokinetic chromatography (CD-MEKC). The dipeptides contained one or two chiral centers. In the case of several dipeptides containing two chiral centers, all... |
8589458 | Structural analysis of the p62 complex, an assembly of O-linked glycoproteins that localizes near the central gated channel of the nuclear pore complex. | The p62 complex is an oligomeric assembly of O-linked glycoproteins of the nuclear pore complex that interacts with cytosolic transport factors and is part of the machinery for nuclear protein import. In this study we have purified the p62 complex from rat liver nuclear envelopes and analyzed its structure and composit... |
8563632 | Irreversible thermal denaturation of Torpedo californica acetylcholinesterase. | Thermal denaturation of Torpedo californica acetylcholinesterase, a disulfide-linked homodimer with 537 amino acids in each subunit, was studied by differential scanning calorimetry. It displays a single calorimetric peak that is completely irreversible, the shape and temperature maximum depending on the scan rate. Thu... |
8563622 | Structure comparison of native and mutant human recombinant FKBP12 complexes with the immunosuppressant drug FK506 (tacrolimus). | The consequences of site-directed mutagenesis experiments are often anticipated by empirical rules regarding the expected effects of a given amino acid substitution. Here, we examine the effects of "conservative" and "nonconservative" substitutions on the X-ray crystal structures of human recombinant FKBP12 mutants in ... |
8594991 | Dual functionalities of 4-aminodiphenylamine in enzymatic assay and mediated biosensor construction. | 4-Aminodiphenylamine (N-phenyl-1,4-phenylenediamine, CAS 101-54-2) and its water-soluble HCl salt (CAS 2198-59-6) were demonstrated to be efficient mediators for glucose oxidase, lactate oxidase, xanthine oxidase, and lysine oxidase. Using cyclic voltammetry, single oxidative peak potentials were observed for scans ran... |
8585719 | Staphylococcus aureus penicillin-binding protein 4 and intrinsic beta-lactam resistance. | Increased levels of production of penicillin-binding protein PBP 4 correlated with in vitro acquired intrinsic beta-lactam resistance in a mutant derived from a susceptible strain of Staphylococcus aureus, strain SG511 Berlin. Truncation of the PBP 4 C-terminal membrane anchor abolished the PBP 4 content of cell membra... |
8557573 | Antibiotic GE37468 A: a novel inhibitor of bacterial protein synthesis. II. Structure elucidation. | GE37468 A is a novel antibiotic produced by Streptomyces sp. ATCC 55365. It has molecular mass 1309.48 and formula C59H52O12N14S5 and belongs to the thiazolyl peptide group of antibiotics. The structure was elucidated by 1H and 13C NMR and MS studies on intact molecule and its hydrolysis products. The antibiotic is a h... |
8557571 | Two conformers of the glycopeptide antibiotic teicoplanin with distinct ligand binding sites. | The clinically important vancomycin group glycopeptide antibiotics, which act by blocking cell wall synthesis, are crucial in the treatment of methicillin resistant Staphylococcus aureus. All of the group members studied so far, with the apparent exception of teicoplanin, enhance their antibiotic action by the formatio... |
8587046 | Improvement of nasal bioavailability of luteinizing hormone-releasing hormone agonist, buserelin, by cyclodextrin derivatives in rats. | The effects of chemically modified cyclodextrins on the nasal absorption of buserelin, an agonist of luteinizing hormone-releasing hormone, were investigated in anesthetized rats. Of the cyclodextrins tested, dimethyl-beta-cyclodextrin (DM-beta-CyD) was the most effective in improving the rate and extent of the nasal b... |
8587041 | Solvent effects on chemical processes. 10. Solubility of alpha-cyclodextrin in binary aqueous-organic solvents: relationship to solid phase composition. | The equilibrium solubility at 25 degrees C of alpha-cyclodextrin was measured in several binary aqueous-organic solvent mixtures, the organic cosolvents being methanol, 2-propanol, ethylene glycol, and acetone. Solubility maxima were observed as the solvent composition was varied from pure water to pure cosolvent. The ... |
8540986 | Procel burn cover used as a total body dressing in burns. | A 26-month-old boy sustained a scald injury covering 83 per cent of his total body surface area (TBSA). He also developed sepsis and multiorgan failure (MOF). Locally he was treated with Procel burn cover and silver sulphadiazine cream (SSD) for 23 days. By using Procel, the dressing-change time was shortened significa... |
8562013 | [Stereoselective analysis of pharmaceutical compounds in biological fluids with capillary electrophoresis]. | Biological fluids drugs analysis are important to investigate the pharmacokinetic and pharmacodynamic of the subministered compounds for the comprehension of their behaviour and bioavailability. Many pharmaceutical preparations contain a chiral molecule as active compound often as racemic mixture of the two enantiomers... |
8576323 | Mycobacterium conspicuum sp. nov., a new species isolated from patients with disseminated infections. | A new type of slowly growing, nonphotochromogenic mycobacterium was recovered from two patients with disseminated disease. The growth characteristics, acid fastness, acids were consistent with those for Mycobacterium species. The results of biochemical investigations, lipid analyses, and comparative 16S rRNA sequencing... |
8580356 | The relationship between ligand-binding thermodynamics and protein-ligand interaction forces measured by atomic force microscopy. | The interaction forces between biotin and a set of streptavidin site-directed mutants with altered biotin-binding equilibrium and activation thermodynamics have been measured by atomic force microscopy. The AFM technique readily discriminates differences in interaction force between the site-directed (Trp to Phe or Ala... |
8580341 | Bilayer nanotubes and helical ribbons formed by hydrated galactosylceramides: acyl chain and headgroup effects. | The molecular basis of bilayer tubule formation in hydrated galactosylceramide (GalCer) dispersions has been investigated by synthesizing different chain-pure GalCers and examining their aqueous mesomorphic phase structure by freeze fracture and negative-stain electron microscopy. Thermotropic characterization of the G... |
8580329 | Interaction of picrotoxin with GABAA receptor channel-lining residues probed in cysteine mutants. | We used the substituted-cysteine-accessibility method to identify the channel-lining residues in a region (257-261) near the putative cytoplasmic end of the M2 membrane-spanning segment of the rat gamma-aminobutyric acid type A (GABAA) receptor alpha 1 subunit. The residues alpha 1Val257 and alpha 1Thr261 were accessib... |
8580323 | Glutamate substitution in repeat IV alters divalent and monovalent cation permeation in the heart Ca2+ channel. | In voltage-gated ion channels, residues responsible for ion selectivity were identified in the pore-lining SS1-SS2 segments. Negatively charged glutamate residues (E393, E736, E1145, and E1446) found in each of the four repeats of the alpha 1C subunit were identified as the major determinant of selectivity in Ca2+ chan... |
8578589 | Molecular recognition between membrane-spanning polypeptides. | Integral membrane proteins have recently been shown to recognize and interact with other proteins within the membrane, either mimicking or altering their function, and with the lipid bilayer itself, resulting in a reorganization of native membrane protein. Membrane proteins are difficult to study using conventional met... |
8574392 | Evaluation of an optically active crown ether for the chiral separation of di- and tripeptides. | The direct optical resolution of a number of di- and tripeptides was achieved by capillary zone electrophoresis using an enantioselective crown ether as buffer additive. The protonated primary amines form inclusion complexes with the crown ether. Chiral resolution is based on different stability constants of the diaste... |
8524642 | The amino-terminal tails of the core histones and the translational position of the TATA box determine TBP/TFIIA association with nucleosomal DNA. | We establish that the TATA binding protein (TBP) in the presence of TFIIA recognizes the TATA box in nucleosomal DNA dependent on the dissociation of the amino-terminal tails of the core histones from the nucleosome and the position of the TATA box within the nucleosome. We examine TBP/TFIIA access to the TATA box with... |
8527423 | Dopamine and GABAA receptor imbalance after ovariectomy in rats: model of menopause. | A peak of first episodes of schizophrenia can occur in postmenopausal women. Furthermore, tardive dyskinesia is more common in postmenopausal women than in men of comparable age. This study investigated the effect of ovariectomy (2 weeks or 3 months) in rats as a model of decreased gonadal function associated with meno... |
8536265 | Isolation and characterization of novel heterogeneous branched cyclomalto-oligosaccharides (cyclodextrins) produced by transgalactosylation with alpha-galactosidase from coffee bean. | Transgalactosylated derivatives of cyclomalto-hexaose (alpha CD), -heptaose (beta CD), and -octaose (gamma CD) were synthesized by alpha-galactosidase from coffee bean using melibiose as a donor and alpha CD, beta CD or gamma CD as an acceptor. Mono- and di-O-alpha-D- galactosylated CDs were isolated and purified by HP... |
8521829 | Intron-encoded endonuclease I-TevI binds as a monomer to effect sequential cleavage via conformational changes in the td homing site. | I-TevI, the intron-encoded endonuclease from the thymidylate synthase (td) gene of bacteriophage T4, binds its DNA substrate across the minor groove in a sequence-tolerant fashion. We demonstrate here that the 28 kDa I-TevI binds the extensive 37 bp td homing site as a monomer and significantly distorts its substrate. ... |
8530914 | Acquisition of nerve dependence for the formation of a regeneration blastema in amputated hindlimbs of larval Xenopus laevis: the role of limb innervation and that of limb differentiation. | In larval and adult urodeles and late-stage larval anurans, blastema formation after limb amputation requires an adequate nerve supply. Experimental evidence obtained from aneurogenic limbs indicates that, in urodeles, the acquisition of nerve dependence during embryonic development is due to the "addiction" of limb ti... |
8556738 | Chemoenzymatic synthesis of 6 omega-S-alpha-D-glucopyranosyl-6 omega-thiomaltooligosaccharides: their binding to Aspergillus niger glucoamylase G1 and its starch-binding domain. | A coupling reaction of cyclodextrin glucosyltransferase (CGTase) with glucose and 6-deoxy-6-iodo-cyclomaltoheptaose (1), in the presence of glucoamylase, followed by acetylation, led to a convenient synthesis of acetylated 6III-deoxy-6III-iodo-maltotriose (2) and 6IV-deoxy-6IV-iodomaltotraose (3). Nucleophilic displace... |
7498463 | Self-association of CPV3, an avian thymic parvalbumin. | The avian parvalbumin called CPV3 readily forms disulfide-linked oligomers. Sedimentation data presented herein reveal that CPV3 also undergoes noncovalent self-association. Interestingly, the noncovalent interaction is promoted by either Ca2+ or Mg2+, whereas covalent complex formation displays an absolute requirement... |
7590259 | Roles of topoisomerase IV and DNA gyrase in DNA unlinking during replication in Escherichia coli. | For a cell to complete DNA replication, every link between the Watson-Crick strands must be removed by topoisomerases. Previously, we reported that the inhibition of topoisomerase IV (topo IV) leads to the accumulation of catenated plasmid replicons to a steady-state level of approximately 10%. Using pulse labeling wit... |
7488360 | Enzyme reactions in the presence of cyclodextrins: biosensors and enzyme assays. | Cyclodextrins, macrocyclic carbohydrates with apolar internal cavities, can form complexes with, and solubilize many normally water-insoluble compounds. Ferrocene and its derivatives, tetrathiafulvalene and tetramethylbenzidine, can function as redox mediators, but are insoluble in water; when they are complexed with c... |
7489712 | A synthetic, chemically modified ribozyme eliminates amelogenin, the major translation product in developing mouse enamel in vivo. | Ribozymes are small RNA structures capable of cleaving RNA target molecules in a catalytic fashion. Designed ribozymes can be targeted to specific mRNAs, blocking their expression without affecting normal functions of other genes. Because of their specific and catalytic mode of action ribozymes are ideal agents for the... |
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