id stringlengths 4 8 | title stringlengths 1 642 | abstract stringlengths 50 17.9k |
|---|---|---|
2376217 | Tissue oxygen extraction in patients with adult respiratory distress syndrome and multiple organ failure. | Multiple organ failure (MOF) associated with adult respiratory distress syndrome (ARDS) secondary to sepsis, trauma, etc., continues to be a syndrome with poor prognosis. It is generally accepted that tissue hypoxia is associated with the subsequent development of MOF. The purpose of this study was to find the relation... |
2376121 | Unusual dissociative behavior of the noncollagenous domain (hexamer) of basement membrane collagen during electrophoresis and chromatofocusing. | The noncollagenous domain of basement membrane collagen exists as a hexamer upon excision with bacterial collagenase. Two hexamer subtypes, differing in subunit composition, have been identified and several additional subtypes are possible because at least two, and possibly more, triple-helical molecules, differing in ... |
2362945 | Model for the interaction of amphiphilic helices with troponin C and calmodulin. | Crystals of troponin C are stabilized by an intermolecular interaction that involves the packing of helix A from the N-terminal domain of one molecule onto the exposed hydrophobic cleft of the C-terminal domain of a symmetry related molecule. Analysis of this molecular recognition interaction in troponin C suggests a p... |
2141735 | Inhibition reactivation myofibrillar ATPase technique for demonstration of three fiber types in a single cryostat muscle section. | An inhibition reactivation technique was used for histochemical staining of human skeletal muscle sections. Myofibrillar ATPase activity was inhibited by sodium hydroxymercuribenzoate (2.5 mM in 0.1 M Tris-HCl buffer, pH 7.2-7.5, 30 min) and successively reactivated by cysteine which was added to incubation solution (1... |
2193243 | Protein structure: the primary substrate for memory. | The motility of protein structure, the existence of discrete conformational states, and the multifarious modes of supramolecular protein organization seem to underlie neuronal plasticity. These aspects of protein structure are surveyed from the viewpoint of their potential role in short-term and long-term memory. It is... |
2193149 | A genetic model for the study of abnormal nerve-muscle interactions at the level of excitation-contraction coupling: the mutation muscular dysgenesis. | Excitation-contraction in muscle fibers are coupled through a complex mechanism involving multiproteic components located at a specialized cellular site, the triadic junction. Triads in normal muscle fiber result from the apposition of sarcoplasmic reticulum citernae and T-tubule and possess strikingly organized ultras... |
2112670 | The importance of intercalation in the covalent binding of benzo(a)pyrene diol epoxide to DNA. | The primary mode of non-covalent interaction of the strong carcinogen, benzo(a)pyrene diol epoxide, with DNA is through intercalation. It has variously been suggested that intercalative complexes may be prerequisite for either covalent binding or DNA-catalysed hydrolysis of the epoxide or both. Geacintov [Geacintov, N.... |
2190837 | The development of new radiopharmaceuticals. | The development of new radiopharmaceuticals is the basis of the continuing growth of nuclear medicine. Chemical interactions of electron clouds in their three-dimensional conformations bring together, in the process of molecular recognition, the reaction of antibody and antigen, receptor and ligand, enzyme and substrat... |
2345776 | Enhancement of specific biological activity of dipyridamole by complexation with beta-cyclodextrin. | Dipyridamole forms an inclusion complex with beta-cyclodextrin (dip-beta-CD) which shows better solubility and bioavailability than the uncomplexed compound. The present studies have demonstrated that dip-beta-CD is more effective than dipyridamole either as base or HCl (dispersed or not in lactose) on some important c... |
2337940 | Utility of 2-hydroxypropyl-beta-cyclodextrin in an intramuscular injectable preparation of nimodipine. | Possible utility of hydroxyalkylated beta-cyclodextrin (beta-CyD) derivatives as parenteral drug carriers was investigated, using nimodipine, a dihydropyridine derivative with calcium antagonistic action, as a model drug. The aqueous solubility of nimodipine increased linearly with increase in the concentration of hydr... |
2327256 | Production and investigating of tablets containing furosemide and beta-cyclodextrin. | Furosemide is a very active drug with an excellent saluretic effect, but it dissolves in water only with difficulty. Furosemide products with beta-cyclodextrin (CD) have been made by five methods, and it has been established that most drugs are liberated most quickly from the kneaded product for the 12.72% combinations... |
2326164 | The solution structure of the intramolecular photoproduct of d(TpA) derived with the use of NMR and a combination of distance geometry and molecular dynamics. | One and two dimensional NMR techniques have been used together with molecular modelling to obtain the solution structure for the photoproduct d(TpA)*. The NMR data confirm that the cyclobutane linkage is formed between the bonds thymine C6-C5 and adenine C5-C6. The 2D NOE data are used as constraints in a distance geom... |
2324219 | Separation of carotenes on cyclodextrin-bonded phases. | The separation of carotenoids and retinoids on a beta-cyclodextrin-bonded stationary phase with conventional mobile phases is reported. Compounds studied include beta-carotene (all-trans), 15,15'-cis-beta-carotene, 7,8,7',8'-dihydro-beta-carotene, alpha-carotene, lycopene, lutein, zeaxanthin, retinal, retinol, retinol ... |
2324212 | Effect of alcohol chain length, concentration and polarity on separations in high-performance liquid chromatography using bonded cyclodextrin columns. | The effect of alcohol chain length, concentration and polarity on separation in high-performance liquid chromatography using beta-cyclodextrin-bonded silica is discussed. The results show that retention times cannot be predicted merely from the polarity of the binary mobile phase. Although organic modifiers with the sa... |
2318188 | Enantiomer resolution in immobilized pH gradient gels via inclusion of a chiral discriminator. | The separation of enantiomeric forms of dansylated amino acids by isoelectric focusing in immobilized pH gradients (IPG) is demonstrated for the first time. Separations occur in a pH 3.0-4.0 IPG interval, in presence of 7Murea, 10% methanol and 60 mM beta-cyclodextrin (CD) as chiral discriminator. It is found that the ... |
2313902 | [Peculiar increase of plasma plasminogen activator inhibitor 1 levels in patients with hemophagocytic histiocytosis]. | There was a markedly significant increase of plasma levels of tissue-type plasminogen activator, plasminogen activator inhibitor 1 (PAI-1) and PAI activity in 3 patients with hemophagocytic histiocytosis (HPH) as compared with DIC patients with multi-organ failure (MOF). Of particular interest was the peculiar increase... |
1689994 | Mapping of viral epitopes with prokaryotic expression products. | Several systems are available for the expression of foreign gene sequences in Escherichia coli. We describe the use of prokaryotic expression products of viral gene fragments in order to identify the regions that specify the binding sites of antibodies. This approach is particularly successful if the antigenicity does ... |
2310225 | Microfibrillar meshwork of the synovial lining and associated broad banded collagen: a clue to identity. | The surface layer of synovial interstitium lining the rabbit knee was studied by transmission electron microscopy. Over a distance of 2-3 microns normal to the surface the interstitium contained a network of fine microfibrils (diameter 9.3 (0.7) nm, mean (SEM] which was quite dense in places (fractional area of project... |
2106596 | Studies on antiplatelet effect of OP-41483, a prostaglandin I2 analog, in experimental animals. I. Effect on platelet function and thrombosis. | Antiplatelet and antithrombotic effects of OP-41483, a PGl2 analog, were studied in experimental animals, and the following results were obtained: 1) With 10 min-intravenous infusion to guinea pigs, OP-41483 inhibited platelet adhesiveness and platelet aggregation at 300-1000 ng/kg/min and 1000 ng/kg/min, respectively.... |
2304981 | Photoreactions of macrocyclic dyes bound to human serum albumin. | The photophysical properties of tetrakis(4-sulfonatophenyl)porphyrin (H2TSPP), its tin (IV) complex (SnTSPP), aluminium(III) trisulfonatophthalocyanine (AIPCS), and the corresponding zinc(II) complex (ZnPCS), have been measured in H2O, D2O, and upon binding to human serum albumin (HSA). The triplet excited states of th... |
2302850 | Molecular recognition in allergic contact dermatitis. The concept of double-headed haptens. | The sensitizing capacity of double-headed haptens containing the pyrocatechol and alpha-methylene-gamma-butyrolactone groups reveals that only the pyrocatechol end is recognized as a sensitizer. Prior sensitization to the double-headed hapten provides protection against (induces immune tolerance to) further sensitizati... |
1967949 | Interaction of hydrophobic organic compounds with mercury adsorbed dioleoylphosphatidylcholine monolayers. | The interaction of hydrophobic organic compounds with biological membranes is an important factor in their biological activity. A fundamental insight into the mechanisms can be obtained by examining the influence of these substances on model membrane systems. The effect of four groups of hydrophobic aromatic compounds ... |
1689153 | Nucleotide sequence of the raw-starch-digesting amylase gene from Bacillus sp. B1018 and its strong homology to the cyclodextrin glucanotransferase genes. | The gene coding for the raw-starch-digesting amylase from Bacillus sp. B1018 was cloned into Escherichia coli, and its nucleotide sequence was determined. Starting at an ATG codon, there was an open reading frame composed of 2139 bp (713 amino acids). The NH2-terminal portion encoded a 27 amino acid-long signal peptide... |
2154183 | Relationship between lipid saturation and lipid-protein interaction in liver mitochondria modified by catalytic hydrogenation with reference to cardiolipin molecular species. | Lipid acyl double bonds in isolated mitochondrial membranes were gradually reduced by palladium-complex-catalysed hydrogenation, and the resulting saturation was monitored by fatty acid analysis of phosphatidylcholine, phosphatidylethanolamine and cardiolipin. The courses of hydrogenation of these phospholipids suggest... |
2302170 | A novel preparative method for the isolation of avidin and riboflavin-binding glycoprotein from chicken egg-white by the use of high-performance liquid chromatography. | A method for the rapid preparative isolation of highly purified avidin using h.p.l.c. on a powerful cation-exchanger TSK SP-5PW column has been developed. The method is based on the following properties of avidin: solubility at a high (NH4)2SO4 concentration, stability and relatively low solubility in organic solvents,... |
2137164 | GAP-43 in growth cones is associated with areas of membrane that are tightly bound to substrate and is a component of a membrane skeleton subcellular fraction. | To ascertain the subcellular localization of the growth-associated protein GAP-43 in growth cones, we isolated growth cones from the forebrains of neonatal rats. Anti-GAP-43 immunoreactivity in these isolated growth cones (IGCs) resembled that seen in cultured growth cones in 2 respects: First, in substrate-attached IG... |
2153773 | Long-term potentiation and activity-dependent retinotopic sharpening in the regenerating retinotectal projection of goldfish: common sensitive period and sensitivity to NMDA blockers. | The regenerating retinotectal projection in goldfish goes through an activity-driven refinement that appears to involve the elimination of inappropriate branches from early arbors. Retinotopically appropriate branches may be stabilized because the normally correlated firing of neighboring ganglion cells causes summatio... |
2298272 | Murine spleen culture: homing of hemopoietic progenitor cells to spleen is not mediated by a similar mechanism to that in marrow. | We have previously shown that in long-term bone marrow cultures (LTMC) the specific recognition and binding of hemopoietic stem cells to stroma, which we call "homing," is mediated by a recognition mechanism involving a surface membrane lectin with galactosyl and mannosyl specificities. Subsequent in vivo studies in le... |
2298216 | Metal-ion-governed molecular recognition: extent of intramolecular stack formation in mixed-ligand--copper(II) complexes containing a heteroaromatic N base and an adenosine monophosphate (2'AMP, 3'AMP, or 5'AMP). A structuring effect of the metal-ion bridge. | Stability constants of mixed-ligand Cu(Arm)(AMP) complexes [where Arm = 2,2'-bipyridyl (Bpy) or 1,10-phenanthroline (Phen) and AMP2- = 2'AMP2-, 3'AMP2- or 5'AMP2-] were determined by potentiometric pH titrations in aqueous solution at I = 0.1 M (NaNO3) and 25 degrees C. The ternary Cu(Arm)(AMP) complexes are more stabl... |
2104986 | Characterization of a class of nonformylated Enterococcus faecalis-derived neutrophil chemotactic peptides: the sex pheromones. | Bacteria produce a heterogeneous mixture of neutrophil chemotactic agents in culture filtrates. Formylmethionyl peptides have been shown to comprise a significant portion of the chemotactic activity in bacterial culture filtrates; however, not all of the chemotactic agents in bacterial culture filtrates are formylated ... |
2404282 | Histidine-94 is the only important histidine residue in the melibiose permease of Escherichia coli. | Oligonucleotide-directed, site-specific mutagenesis has been utilized to modify the melB gene of Escherichia coli such that each of the seven His residues in the melibiose permease has been replaced with Arg. Replacement of His-213, His-442, or His-456 has no significant effect on permease activity, while permease with... |
2153288 | Production of abiotic receptors by molecular imprinting of proteins. | When a protein is dissolved in a concentrated aqueous solution of a multifunctional organic compound, freeze-dried, and washed with an anhydrous organic solvent to remove the ligand, the resultant "imprinted" protein preparation binds up to 30-fold more of the template compound in anhydrous solvents than the nonimprint... |
2404273 | Expression of a cloned streptavidin gene in Escherichia coli. | We describe the construction of systems for expressing the cloned streptavidin gene in Escherichia coli. Although the streptavidin gene is extremely lethal to the host cells, because of the strong biotin binding of the gene product, the gene was expressed efficiently in E. coli by using T7 RNA polymerase/T7 promoter ex... |
2104879 | Phagocytosis of Histoplasma capsulatum yeasts and microconidia by human cultured macrophages and alveolar macrophages. Cellular cytoskeleton requirement for attachment and ingestion. | Phagocytosis of Histoplasma capsulatum (Hc) yeasts and microconidia by human macrophages (M phi) was quantified by a fluorescence quenching technique. Phagocytosis of unopsonized Hc yeasts by monocyte-derived M phi and human alveolar M phi (AM) was rapid. After 60 min, 79% of cultured M phi and 59% of AM had ingested a... |
1967250 | Introduction of guest peptides into Escherichia coli alkaline phosphatase. Excision and purification of a dynorphin analogue from an active chimeric protein. | High relative mutability may be a common property of the surfaces of all or most proteins and may be exploited during evolution not only to alter molecular recognition but to modify catalytic functions as well. Conservative amino acid substitutions often can be expected to cause minimal structural alterations, but the ... |
1688533 | Enhancement of rat peripheral nerve regeneration through artery-including silicone tubing. | Regeneration of rat sciatic nerve across a 5-mm excised gap was investigated after the proximal and distal stump were inserted into a silicone tubing including a native artery. Usual tubulation (silicone tube only) was used as the control. After 4, 8, and 15 weeks, the extent of nerve regeneration was evaluated electro... |
2104801 | The tramtrack gene encodes a Drosophila finger protein that interacts with the ftz transcriptional regulatory region and shows a novel embryonic expression pattern. | We have identified a Drosophila zinc-finger protein, which binds to a number of sites in the transcriptional control regions of the pair-rule gene fushi-tarazu (ftz). The expression pattern of the mRNA that encodes this protein is essentially complementary to that of ftz both prior to blastoderm formation and during ge... |
2104660 | The Drosophila Hrb98DE locus encodes four protein isoforms homologous to the A1 protein of mammalian heterogeneous nuclear ribonucleoprotein complexes. | The Drosophila Hrb98DE locus encodes proteins that are highly homologous to the mammalian A1 protein, a major component of heterogeneous nuclear ribonucleoprotein (RNP) particles. The Hrb98DE locus is transcribed throughout development, with the highest transcript levels found in ovaries, early embryos, and pupae. Eigh... |
2403638 | Cell type-specific protein-DNA interactions in the human zeta-globin upstream promoter region: displacement of Sp1 by the erythroid cell-specific factor NF-E1. | The protein-DNA interactions of the upstream promoter region of the human embryonic zeta-globin gene in nuclear extracts of erythroid K562 cells and nonerythroid HeLa cells were analyzed by DNase I footprinting, gel mobility shift assay, methylation interference, and oligonucleotide competition experiments. There are m... |
2403635 | Chromosome instability mutants of Saccharomyces cerevisiae that are defective in microtubule-mediated processes. | By using a multiply marked supernumerary chromosome III as an indicator, we isolated mutants of Saccharomyces cerevisiae that display increased rates of chromosome loss. In addition to mutations in the tubulin-encoding TUB genes, we found mutations in the CIN1, CIN2, and CIN4 genes. These genes have been defined indepe... |
2104614 | Cloning and DNA sequence of the gene coding for the major sigma factor from Myxococcus xanthus. | The gene for a sigma factor (rpoD) was cloned from Myxococcus xanthus, a soil bacterium which differentiates to form fruiting bodies upon starvation for nutrients. The DNA sequence of the gene was determined, and an open reading frame encoding a polypeptide of 708 amino acid residues (Mr = 80,391) was identified. Excep... |
2294058 | Bordetella pertussis filamentous hemagglutinin: evaluation as a protective antigen and colonization factor in a mouse respiratory infection model. | Filamentous hemagglutinin (FHA) is a cell surface protein of Bordetella pertussis which functions as an adhesin for this organism. It is a component of many new acellular pertussis vaccines. The proposed role of FHA in immunity to pertussis is based on animal studies which have produced some conflicting results. To cla... |
2152886 | Selective binding of Trypanosoma cruzi to host cell membrane polypeptides. | An adaptation of the immunoblotting technique was used to investigate binding interactions between Trypanosoma cruzi and mammalian host cells at the molecular level. A specific binding interaction was observed between T. cruzi and two host cell membrane polypeptides with molecular masses of approximately 32 and 34 kilo... |
1818322 | The release of naproxen in fatty suppository bases by beta-cyclodextrin complexation. | The effect of beta-cyclodextrin (beta-CD) on the release of naproxen (1) from fatty suppository bases was investigated. The solid complexes of 1 with beta-CD in a molar ratio of 1:1 were prepared by using the kneading, co-precipitation and grinding method. Witepsol H15 and Massa Estarinum B suppositories were prepared,... |
1818089 | Modeling and conformation analysis of beta-cyclodextrin complexes. | A series of beta-cyclodextrin complexes containing various guest molecules was studied using computer-aided molecular modeling and conformation analysis techniques. The geometry of each complex was studied using crystallographic data. The positions of the glycosidic O4 atoms indicate that the beta-cyclodextrin molecule... |
1687821 | Determination of antihistamines in pharmaceuticals by capillary electrophoresis. | Capillary electrophoresis with on-column UV detection at 214 nm was used to separate a group of nine antihistamines. All these compounds were satisfactorily separated within ca. 6 min using a mixed carrier system containing sodium dodecyl sulphate with beta-cyclodextrin and tetrabutylammonium hydrogensulphate as modifi... |
1818062 | Use of dabsylation, column switching and chiral separation for the determination of a renin inhibitor in rat, marmoset and human plasma. | A high-performance liquid chromatographic method with column switching was developed for the determination of the renin inhibitor Ro 42-5892/001, (S)-alpha-[(S)-alpha-[(tert.-butylsulphonyl)methyl]hydrocinnama mido]-N- [(1S,2R,3S)-1-(cyclohexylmethyl)-3-cylcopropyl-2, 3-dihydroxypropyl]imidazole-4-propionamide methanes... |
1726270 | Engineering of functional supramacromolecular complexes of proteins (enzymes) using reversed micelles as matrix microreactors. | The size of the inner water cavity of reversed micelles formed in a triple system 'water-surfactant-organic solvent' can be widely varied by changing the degree of surfactant hydration. This gives grounds to use reversed micelles as matrix microreactors for the design of supramolecular complexes of proteins. Using ultr... |
1817145 | The development and fate of the dental lamina of the mandibular first molar tooth in the rat. | The lamina of the first mandibular molar teeth of rats, age range 13 d intrauterine (i.u.) to 16 d postnatal (p.n.), was examined by light and transmission electron microscopy to establish histological baselines of its development and fate. All material was obtained from animals anaesthetised with ether, killed by cerv... |
1667856 | One-bond carbon-proton coupling constants: angular dependence in alpha-linked oligosaccharides. | An investigation is presented of the angular dependence of 1JC,H in model compounds related to alpha-linked oligosaccharides. Values calculated by FPT formulation in the semi-empirical INDO method for models of (1----1)-, (1----2)-, (1----3)-, and (1----4)-linked disaccharides were compared, and the effect of the orien... |
1816924 | N.m.r. studies of the conformation of analogues of methyl beta-lactoside in methyl sulfoxide-d6. | The 1H- and 13C-n.m.r. spectra of solutions of methyl beta-lactoside (1), all of its monodeoxy derivatives (2, 3, 6-10), the 3-O-methyl derivative (4), and methyl 4-O-beta-D-galactopyranosyl-D-xylopyranoside (5) in methyl sulfoxide-d6 have been analysed. The n.O.e.'s and specific desheildings indicate similar distribut... |
1816915 | Controlled reduction of acarbose: conformational analysis of acarbose and the resulting saturated products. | Saturation of the double bond in the non-reducing terminal unit of the tetrasaccharide amylase inhibitor, acarbose (1), with Raney nickel as the catalyst and at pH 8, gave 57% of a approximately 1:1 mixture of the 5a-carba-gluco (2) and -ido (3) isomers together with cleavage products including 26% of the trisaccharide... |
1816739 | Ion-selective electrode studies on novel organic molecule sensors. | Researches on prospects for novel ion-selective electrodes, based on organic molecule sensors, are described. The organic molecules are large crown ethers extending from bis(metaphenylene)-26-crown-8 to bis(metaphenylene)-38-crown-12, small crown ethers, bis-crown ethers, and acyclic polyethers consisting of diphenyl e... |
1815480 | Release of ketoprofen from dermal bases in presence of cyclodextrins: effect of the affinity constant determined in semisolid vehicles. | We describe a method to determine the affinity constant values between Ketoprofen and beta-cyclodextrin and hydroxypropyl-beta-cyclodextrin in semisolid vehicles. The method is based on the diffusion of the drug, released from semisolid vehicles, through a lipidic non porous membrane. The affinity constants of Ketoprof... |
1840000 | Tachykinin-, calcitonin gene-related peptide-, and protein gene product 9.5-immunoreactive nerve fibers in alveolar walls of mammals. | The presence and distribution of the presumed pan-neural marker protein gene product 9.5 (PGP)- and peptide-immunoreactive (ir) nerve fibers in alveolar walls of various species was investigated by light microscopic single and double staining immunohistochemistry. PGP-, tachykinin (TK)-, and calcitonin gene-related pep... |
1815076 | Carbon-13 nuclear magnetic resonance study of naproxen interaction with cyclodextrins in solution. | Changes in naproxen (NAP) 13C-chemical shifts were measured as a function of the concentration of alpha-, beta-, and gamma-cyclodextrin (alpha Cd, beta Cd, and gamma Cd, respectively) in aqueous solution in order to obtain details on the mechanism, geometry, and stoichiometry of the respective interactions. The probabl... |
1815075 | Nuclear magnetic resonance investigation of the stoichiometries in beta-cyclodextrin:steroid inclusion complexes. | Nuclear magnetic resonance at high field has been used to investigate the stoichiometries of pharmacologically important beta-cyclodextrin:steroid complexes. This technique provides evidence for the existence of true inclusion complexes and allows unequivocal determination of the stoichiometry for complexes obtained in... |
1814608 | Solubilization of steviolbioside and steviolmonoside with gamma-cyclodextrin and its application to selective syntheses of better sweet glycosides from stevioside and rubusoside. | 1,4-alpha-Glucosylation at the 13-O-glycosyl moiety of stevioside (S) and rubusoside (RU) results in a significant increase of sweetness. Saponification of the 19-COO-beta-glucosyl linkage of S and RU yielded steviolbioside (SB) (= 13-O-beta-sophorosyl-steviol) and steviolmonoside (SM) (= 13-O-beta-glucosyl-steviol), r... |
1813110 | Crystal structure of 2-O-[(S)-2-hydroxypropyl]cyclomaltoheptaose. | 2-O-[(S)-2-Hydroxypropyl]cyclomaltoheptaose crystallises in the monoclinic space group P2(1) with unit-cell dimensions a = 15.072(1), b = 10.409(1), c = 20.623(2) A, and beta = 108.52(1) degrees. The structure was solved by X-ray diffraction and refined to an R-value of 0.096. The macrocyclic ring of the cyclomaltohept... |
1839890 | Branched saccharides formed by the action of His-modified cyclodextrin glycosyltransferase from Klebsiella pneumoniae M 5 al on starch. | Digestion of potato starch with His-modified alpha-cyclodextrin glycosyltransferase from Klebsiella pneumoniae M 5 al yielded branched tetra- to nona-saccharides, as revealed by debranching with pullulanase. Maltose and maltotriose stubs preponderated together with small proportions of D-glucose stubs. The branched sac... |
1813102 | Synthesis of some 2-O-(2-hydroxyalkyl) and 2-O-(2,3-dihydroxyalkyl) derivatives of cyclomaltoheptaose. | On alkylation of cyclomaltoheptaose with oxiranes, promoted by alkali of low concentration, substitution at secondary positions, particularly at O-2, is favoured. The reaction has been used to prepare the 2-O-[(R)- and (S)-2-hydroxypropyl], 2-O-(2-hydroxy-2-methylpropyl), 2-O-[(R)- and (S)-2,3-dihydroxypropyl], and 2-O... |
1812288 | Effect of gamma-interferon on fibroblast proliferation and collagen synthesis after glaucoma filtering surgery in white rabbits. | Failure of a glaucoma filtering operation mainly results from scarring at the filtering wound, and postoperative proliferation and migration of fibroblasts play an important role histologically in the formation of scar tissue. As an inhibitory agent for fibroblast proliferation, gamma-interferon has been introduced, an... |
1667289 | Analysis of the 5-HT receptors mediating contractions in the rabbit isolated renal artery. | 1. Using a number of agonist and antagonist compounds, we have attempted to characterize the responses and receptors involved in the effects of 5-hydroxytryptamine (5-HT) in the rabbit isolated renal artery. 2. In vessel segments precontracted with the thromboxane-mimetic agent, U46619 (100 nM), neither 5-HT (10(-8) to... |
1808612 | Effect of 2-hydroxypropyl-beta-cyclodextrin on the ocular absorption of dexamethasone and dexamethasone acetate. | Complexation of dexamethasone (DX) and dexamethasone acetate (DXA) with 2-hydroxypropyl-beta-cyclodextrin (HPCD) was investigated with an ultimate goal of formulating a topical ophthalmic solution of DXA. Aqueous solubility of DX and DXA was markedly increased due to formation of soluble inclusion complexes with HPCD. ... |
1725493 | Toward a more complete 3-D structure of the nuclear pore complex. | The nuclear pore complex (NPC) is a large supramolecular assembly embedded in the double-membraned nuclear envelope (NE) that plays a pivotal role in the exchange of macromolecules and particles between the nucleus and the cytoplasm. Applying various methods of sample preparation to Xenopus laevis whole nuclei and isol... |
1724917 | Alpha 2-macroglobulin restricts plasminogen activation to the surface of RC2A leukemia cells. | Human RC2A myelomonocytic leukemia cells are able to activate the prourokinase (pro-u-PA) they secrete so that active u-PA is present both in serum-free conditioned medium from these cells, as well as on the cell surface. When the cells are grown in serum-containing medium, no u-PA activity can be found in the medium b... |
1798292 | Role of reactive oxygen species in biological processes. | The steady-state formation of prooxidants in cells and organs is balanced by a similar rate of their consumption by antioxidants that are enzymatic and/or nonenzymatic. "Oxidative stress" results from imbalance in this prooxidant-antioxidant equilibrium in favor of the prooxidants. A number of diseases are associated w... |
1839025 | Existence of high- and low-affinity vanadate-binding sites on Ca(2+)-ATPase of the sarcoplasmic reticulum. | The binding of vanadate to isolated sarcoplasmic reticulum (SR) membranes was measured colorimetrically by equilibrium sedimentation and ion exchange column filtration. The concentration dependence of vanadate binding exhibited a biphasic curve with two phases of equal amplitude. A similar biphasic curve of the vanadat... |
1790313 | Bioavailability study of a freeze-dried sodium phenytoin-milk formulation. | The problematic bioavailability of phenytoin's (5,5-diphenylhydantoin) oral formulations serves as a stimulus for examining new formulations and/or administration conditions that may provide more predictable absorption. Attempts to achieve more consistent peroral phenytoin bioavailability from conventional solid dosage... |
1785925 | Identification of a locus within the hydrogenase gene cluster involved in intracellular nickel metabolism in Bradyrhizobium japonicum. | A 0.6-kb fragment of DNA involved in intracellular Ni metabolism was isolated and cloned from a cosmid containing 23.2 kb of hydrogenase-related genes of Bradyrhizobium japonicum. This locus is located 8.3 kb upstream of the hydrogenase structural genes. The hydrogenase activity of a mutant with a gene-directed mutatio... |
1368763 | Enzymic production of sweet stevioside derivatives: transglucosylation by glucosidases. | For the purpose of improving sweetness and a further study on the structure-sweetness relationship of steviol glycosides, transglycosylation of stevioside by a variety of commercial glucosidases was investigated. It was revealed that two alpha-glucosidases gave glucosylated products. Transglucosylation of stevioside by... |
1723487 | Surface layers of bacteria. | Since bacteria are so small, microscopy has traditionally been used to study them as individual cells. To this end, electron microscopy has been a most powerful tool for studying bacterial surfaces; the viewing of macromolecular arrangements of some surfaces is now possible. This review compares older conventional elec... |
1778762 | Possible application to medium-term organ bioassays for renal carcinogenesis modifiers in rats treated with N-ethyl-N-hydroxyethylnitrosamine and unilateral nephrectomy. | The effects of the renal tumor promoters; beta-cyclodextrin (beta-C), DL-serine (DL-S), basic lead acetate (LA), trisodium nitrilotriacetate monohydrate (NTA) and potassium bromate (KB), and diethylene glycol (DEG) as a negative control, on early stage of renal carcinogenesis were investigated in unilaterally nephrecto... |
1777572 | Recognition processes at a functionalized lipid surface observed with molecular resolution. | The specific binding of proteins to functionalized lipid monolayers on aqueous subphases was characterized by neutron reflectivity and fluorescence microscopy measurements. Due to the high affinity and high specificity of their noncovalent interaction, streptavidin (SA) and biotin (vitamin H) were chosen as a model sys... |
1777571 | Dynamical search for bis-penicillamine enkephalin conformations. | Quenched molecular dynamics is used as a conformational search technique for the constrained cyclic analog [D-Pen2,D-Pen5]enkephalin (DPDPE) in a continuum solvent. The results show a Gaussianlike distribution of conformations as a function of energy, unlike the distributions found for simple liquids which have sharp b... |
1663794 | Structures of bovine and human papillomaviruses. Analysis by cryoelectron microscopy and three-dimensional image reconstruction. | The structures of bovine papillomavirus type 1 (BPV-1) and human papillomavirus type 1 (HPV-1) were determined at 2.5 nm resolution by cryoelectron microscopy and three dimensional image reconstruction techniques. As expected, the reconstructions showed that both viruses consist of a T = 7 icosahedral capsid (approxima... |
1723312 | Lipid interaction of Pseudomonas aeruginosa exotoxin A. Acid-triggered permeabilization and aggregation of lipid vesicles. | We have investigated the interaction of Pseudomonas exotoxin A with small unilamellar vesicles comprised of different phospholipids as a function of pH, toxin, and lipid concentration. We have found that this toxin induces vesicle permeabilization, as measured by the release of a fluorescent dye. Permeabilization is du... |
1772849 | Molecular mechanics of the formation of cholic acid micelles. | The molecular mechanics of cholic acid micelle formation were simulated using the Sybyl energy minimization program (MAXIMIN2), developed by Tripos Associates, interfaced with micro-Vax. Before energy minimization, the molecular dimensions of the cholic acid dodecamer C24H40O6, in terms of the unit cell axes a, b, and ... |
1768567 | Age-dependent stereoselective increase in the oral clearance of hexobarbitone isomers caused by rifampicin. | 1. The disposition of hexobarbitone enantiomers before and after rifampicin treatment (600 mg daily for 14 days) was investigated in six young (29 +/- 3 years old) and six elderly (71 +/- 4 years old) healthy male volunteers. Hexobarbitone was given as a single 500 mg oral dose of the racemate. 2. The mean (+/- s.d.) o... |
1765127 | Molecular recognition: models for drug design. | The review takes examples, mostly from the recent literature, to illustrate how an understanding of physico-chemical properties and an appreciation of the molecular shape and electronic properties can lead to a better insight into molecular recognition processes. The techniques used to generate 3-dimensional structures... |
1765126 | Molecular recognition in applied enzyme chemistry. | Molecular recognition impinges upon many fields of biological chemistry, especially those involving catalytic processes. This review gives examples from studies at Strathclyde of both small and macromolecular systems. Mechanism-based enzyme inhibitors are described with reference to dihydrofolate reductase, dihydroorot... |
1765125 | Molecular recognition in antibodies and its application. | The structure and function of immunoglobulins, and the nature of the antibody-antigen interaction are described. Applications of the molecular recognition properties of antibodies are discussed in the areas of immunotherapy, immunoassay, immunotargeting and catalytic antibodies. |
1765121 | Molecular recognition and the development of self-replicating systems. | Weak intermolecular forces lie at the heart of biochemical recognition phenomenon and the last decade has seen much activity in the evaluation of these forces. A number of model systems have been developed including macrocyclic structures and molecular clefts. With these structures it has been possible to measure force... |
1764453 | The uptake of pristane (2,6,10,14-tetramethylpentadecane) into phospholipid bilayers as assessed by NMR, DSC, and tritium labeling methods. | Unilamellar dioleoylphosphatidylcholine (DOPC) liposomes (250 microM) incorporated 2 mol% of [3H]pristane at 37 degrees C after addition of 50 microM pristane solubilized with beta-cyclodextrin. Conventional solubilization in dimethyl sulphoxide resulted in much lower uptake. Premixing of perdeuterated pristane with DO... |
1662385 | Evidence that a formyl-substituted iron porphyrin is the prosthetic group of myeloperoxidase: magnetic circular dichroism similarity of the peroxidase to Spirographis heme-reconstituted myoglobin. | To probe the identity of the active site heme-type prosthetic group of myeloperoxidase, whose structure has not been established unambiguously [proposed structures are (i) a chlorin (dihydroporphyrin) or (ii) a formyl-substituted porphyrin such as present in heme a], Spirographis heme (2-formyl-4-vinyldeuteroheme IX) h... |
1662207 | Denaturation and renaturation of myeloperoxidase. Consequences for the nature of the prosthetic group. | The effects of the chaotropic agent, guanidine HCl, on the chlorinating activity, optical absorption, EPR, and resonance Raman spectra of myeloperoxidase have been studied. In the presence of the agent the Soret optical absorption of the reduced enzyme (lambda max = 474 nm) is blue shifted to 448 nm, a position similar... |
1836996 | Human kidney hexosaminidase A and hexosaminidase B form a complex. | The isolation and purification of human kidney hexosaminidases A and B was carried out. Regulation of the supramolecular organization and catalytic activity of hexosaminidases was investigated in the bis(2-ethylhexyl)sulphosuccinate reversed micellar system modeling the enzyme microenvironment in the lysosomes. It was ... |
1662130 | NMR study of the structural characteristics of variants of yeast iso-1-cytochrome c in which unvaried aromatic residues have been substituted. | The structures of variants of yeast iso-1-cytochrome c, in which the previously unchanged Tyr48 and Tyr48 + Trp59 have been replaced by Phe, have been characterised by NMR. The NMR data indicated that the structures of the variant cytochromes c are very similar to the wild-type protein. In particular, the heme environm... |
1756713 | The surface-exposed tyrosine residue Tyr83 of pea plastocyanin is involved in both binding and electron transfer reactions with cytochrome f. | Site-directed mutants of the pea plastocyanin gene in which the codon for the surface-exposed Tyr83 has been changed to codons for Phe83 and Leu83 have been expressed in transgenic tobacco plants. The mutant proteins have been purified to homogeneity and their conformations shown not to differ significantly from the wi... |
18965323 | Effect of structural variation within sym-(R)dibenzo-16-crown-5-oxyacetic acid resins upon the selectivity and efficiency of alkali-metal cation sorption. | Five new crown ether carboxyhc acid resins have been prepared by condensation polymerization of sym-(R)dibenzo-16-crown-5-oxyacetic acids with formaldehyde. Competitive alkali-metal cation sorption by these novel resins, which contain both ion-exchange and crown ether binding sites for metal ions, has been investigated... |
1661071 | Warner-Lambert/Parke-Davis Award Lecture. Viral pathogenesis of atherosclerosis. Impact of molecular mimicry and viral genes. | Human atherogenesis is a pleiotropic process with an undefined cause. Several pathologic factors have been linked to the disease process, including arterial injury or activation of the endothelium, which may injury or activation of the endothelium, which may initiate proatherosclerotic events in the vessel wall. Athero... |
1747128 | Aluminium transport in blood serum. Binding of aluminium by human transferrin in the presence of human albumin and citrate. | The binding of Al3+ by human serum transferrin has been investigated by u.v.-visible difference spectroscopy. In the presence of 25 mM-HCO3- at pH 7.4, the apparent association constants were found to be 1.69 x 10(12) M-1 and 5.36 x 10(11) M-1. These association constants are pH-dependent, reducing with both increasing... |
1684105 | Conversion of citrate synthase into citryl-CoA lyase as a result of mutation of the active-site aspartic acid residue to glutamic acid. | The active-site aspartic acid residue, Asp-362, of Escherichia coli citrate synthase was changed by site-directed mutagenesis to Glu-362, Asn-362 or Gly-362. Only very low catalytic activity could be detected with the Asp----Asn and Asp----Gly mutations. The Asp----Glu mutation produced an enzyme that expressed about 0... |
1747120 | Mutagenesis of arginine residues in the catalytic cleft of Escherichia coli porphobilinogen deaminase that affects dipyrromethane cofactor assembly and tetrapyrrole chain initiation and elongation. | Substitutions of conserved arginine residues in the catalytic cleft of Escherichia coli porphobilinogen deaminase were constructed by site-specific mutagenesis of the hemC gene. Mutant proteins exhibited a range of defects including the failure to assemble the dipyrromethane cofactor and the inability to initiate and p... |
1747104 | A classification of glycosyl hydrolases based on amino acid sequence similarities. | The amino acid sequences of 301 glycosyl hydrolases and related enzymes have been compared. A total of 291 sequences corresponding to 39 EC entries could be classified into 35 families. Only ten sequences (less than 5% of the sample) could not be assigned to any family. With the sequences available for this analysis, 1... |
1744699 | Sodium-bicarbonate cotransport in retinal Müller (glial) cells of the salamander. | An electrogenic Na+/HCO3- cotransport system was studied in freshly dissociated Müller cells of the salamander retina. Cotransporter currents were recorded from isolated cells using the whole-cell, voltage-clamp technique following the block of K+ conductance with external Ba2+ and internal Cs+. At constant pHo, an out... |
1744583 | Lipopolysaccharide-mediated transcriptional activation of the human tissue factor gene in THP-1 monocytic cells requires both activator protein 1 and nuclear factor kappa B binding sites. | Lipopolysaccharide (LPS) activation of cells of monocytic lineage leads to rapid and transient expression of a set of inflammatory gene products, including tissue factor (TF). This transmembrane receptor is the major cellular initiator of the blood coagulation cascades, and induced expression of TF is postulated to pla... |
1744579 | Human immunodeficiency virus type 1 activates the classical pathway of complement by direct C1 binding through specific sites in the transmembrane glycoprotein gp41. | Human immunodeficiency virus type 1 (HIV-1), in contrast to animal retroviruses such as murine leukemia virus, is not lysed by human complement. Nevertheless, HIV-1 activates complement via the classical pathway independent of antibody, and C3b deposition facilitates infection of complement receptor-bearing cells. Usin... |
1744052 | Characterization of endoglucanase A from Clostridium cellulolyticum. | A construction was carried out to obtain a high level of expression in Escherichia coli of the gene celCCA, coding for the endoglucanase A from Clostridium cellulolyticum (EGCCA). The enzyme was purified in two forms with different molecular weights, 51,000 and 44,000. The smaller protein was probably the result of pro... |
1962451 | Requirements for nuclear localization and supramolecular assembly of a baculovirus polyhedrin protein. | This study defines the requirements for the nuclear localization, stable nuclear association, and supramolecular assembly of a baculovirus polyhedrin protein in lepidopteran insect cells. Fragments of the polyhedrin protein were genetically fused to two different nonnuclear reporter proteins and the intracellular distr... |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.