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Selected AbstractsGene expression signatures in chronic and aggressive periodontitis: a pilot studyEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 3 2004Panos N. Papapanou This pilot study examined gene expression signatures in pathological gingival tissues of subjects with chronic or aggressive periodontitis, and explored whether new subclasses of periodontitis can be identified based on gene expression profiles. A total of 14 patients, seven with chronic and seven with aggressive periodontitis, were examined with respect to clinical periodontal status, composition of subgingival bacterial plaque assessed by checkerboard hybridizations, and levels of serum IgG antibodies to periodontal bacteria assayed by checkerboard immunoblotting. In addition, at least two pathological pockets/patient were biopsied, processed for RNA extraction, amplification and labeling, and used to study gene expression using Affymetrix U-133 A arrays. Based on a total of 35 microarrays, no significantly different gene expression profiles appeared to emerge between chronic and aggressive periodontitis. However, a de novo grouping of the 14 subjects into two fairly robust clusters was possible based on similarities in gene expression. These two groups had similar clinical periodontal status and subgingival bacterial profiles, but differed significantly with respect to serum IgG levels against the important periodontal pathogens Porphyromonas gingivalis, Tannerella forsythensis and Campylobacter rectus. These early data point to the usefulness of gene expression profiling techniques in the identification of subclasses of periodontitis with common pathobiology. [source] Design, Synthesis, and Spectral Luminescent Properties of a Novel Polycarbocyanine Series Based on the 2,2-Difluoro-1,3,2-dioxaborine NucleusEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 9 2008Konstantin Zyabrev Abstract The natures of the chromophores in symmetric polymethine dyes derived from 2,2-difluoro-1,3,2-dioxaborine have been investigated. Ab initio quantum chemical calculations demonstrated that the presence of dioxaborine end residues stabilizes the frontier levels of the corresponding polymethine dye and makes electron-density distribution over the oxygen atoms in the chelate ring more even than in the analogous dye structure with boron-free acyclic end groups. A series of novel symmetric polycarbocyanines and a tricarbocyanine series with variously bridged polymethine chromophores have been synthesized from hitherto unknown pyrimidino-annelated dioxaborines. The absorption, fluorescence and 13C NMR spectroscopic data point to the polymethinic type of electron-density distribution in the 2,2-difluoro-1,3,2-dioxaborine polymethine dye molecules. The fundamental options for controlling the spectral properties of these dyes by modification of their polymethine chains have been evaluated. One of the new compounds synthesized is remarkable among the known open-chain polymethine dyes for its record high fluorescence quantum yield. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Redox-regulated affinity of the third PDZ domain in the phosphotyrosine phosphatase PTP-BL for cysteine-containing target peptidesFEBS JOURNAL, Issue 13 2005Lieke C. J. Van Den Berk PDZ domains are protein,protein interaction modules that are crucial for the assembly of structural and signalling complexes. They specifically bind to short C-terminal peptides and occasionally to internal sequences that structurally resemble such peptide termini. The binding of PDZ domains is dominated by the residues at the P0 and P,2 position within these C-terminal targets, but other residues are also important in determining specificity. In this study, we analysed the binding specificity of the third PDZ domain of protein tyrosine phosphatase BAS-like (PTP-BL) using a C-terminal combinatorial peptide phage library. Binding of PDZ3 to C-termini is preferentially governed by two cysteine residues at the P,1 and P,4 position and a valine residue at the P0 position. Interestingly, we found that this binding is lost upon addition of the reducing agent dithiothrietol, indicating that the interaction is disulfide-bridge-dependent. Site-directed mutagenesis of the single cysteine residue in PDZ3 revealed that this bridge formation does not occur intermolecularly, between peptide and PDZ3 domain, but rather is intramolecular. These data point to a preference of PTP-BL PDZ3 for cyclic C-terminal targets, which may suggest a redox state-sensing role at the cell cortex. [source] A spectroscopic study of the reaction of NAMI, a novel ruthenium(III)anti-neoplastic complex, with bovine serum albuminFEBS JOURNAL, Issue 4 2000Luigi Messori The reaction of Na[transRuCl4Me2SO(Im)] (NAMI; where Im is imidazole), a novel anti-neoplastic ruthenium(III) complex, with BSA, was studied in detail by various physico-chemical techniques. It is shown that NAMI, following chloride hydrolysis, binds bovine serum albumin tightly; spectrophotometric and atomic absorption data point out that up to five ruthenium ions are bound per albumin molecule when BSA is incubated for 24 h with an eightfold excess of NAMI. CD and electronic absorption results show that the various ruthenium centers bound to albumin exhibit well distinct spectroscopic features. The first ruthenium equivalent produces a characteristic positive CD band at 415 nm whereas the following NAMI equivalents produce less specific and less marked spectral effects. At high NAMI/BSA molar ratios a broad negative CD band develops at 590 nm. Evidence is provided that the bound ruthenium centers remain in the oxidation state +3. By analogy with the case of transferrins it is proposed that the BSA-bound ruthenium ions are ligated to surface histidines of the protein; results from chemical modification experiments with diethylpyrocarbonate seem to favor this view. Spectral patterns similar to those shown by NAMI are observed when BSA is reacted with two strictly related ruthenium(III) complexes Na[transRuCl4(Me2SO)2] and H(Im)[transRuCl4(Im)2] (ICR), implying a similar mechanism of interaction in all cases. It is suggested that the described NAMI-BSA adducts may form in vivo and may be relevant for the biological properties of this complex; alternatively NAMI/BSA adducts may be tested as specific carriers of the ruthenium complex to cancer cells. Implications of these findings for the mechanism of action of NAMI and of related ruthenium(III) complexes are discussed. [source] Listeria monocytogenes response regulators important for stress tolerance and pathogenesisFEMS MICROBIOLOGY LETTERS, Issue 1 2001Birgitte H. Kallipolitis Abstract Environmental sensing by two-component signal transduction systems is likely to play a role for growth and survival of Listeria monocytogenes both during transmission in food products and within a host organism. Two-component systems typically consist of a membrane-associated sensor histidine kinase and a gene regulatory protein, the response regulator (RR). We have identified seven putative RR genes in L. monocytogenes LO28 by PCR using degenerate oligonucleotide primers. By insertional inactivation we obtained data suggesting that three of the putative RRs contribute to the pathogenicity of L. monocytogenes in mice. Strikingly, the mutants that were attenuated in virulence also had a decreased ability to grow in the presence of various stress conditions potentially encountered in an infection process. Thus, our data point to a connection between the ability of the putative two-component systems to sense and respond to certain environmental stimuli, and the virulence of L. monocytogenes. [source] How well are velocity effects on ,13C signatures transmitted up the food web from algae to fish?FRESHWATER BIOLOGY, Issue 6 2010JOSEPH B. RASMUSSEN Summary 1. Benthic algae fractionate carbon isotopes less at low water velocities because of reduced boundary layer exchange, and this effect on ,13C is passed on to consumers via trophic transfer. This study examines the relationships between ,13C signatures of consumers (invertebrates and salmonid fishes) and water velocity in the Sainte Marguerite River, QC, Canada, and compares them to patterns for periphyton, both along the river main-stem and in a small tributary. 2. Relationships of ,13C signatures of herbivore/grazers and collector/gatherers with water velocity were strong and similar to those of periphyton, but relationships for filter-feeders were weak, probably reflecting the effect of spatial averaging of their food supply as a result of downstream transport. 3. Velocity effects on salmonid signatures were much weaker than those of lower trophic levels, being barely significant except in the small tributary where the fish were resident and isolated from the main river. In the river main-stem, even when reach standardised (reach mean subtracted from each data point), fish signatures were only weakly related to water velocity. 4. The fidelity with which velocity effects are transmitted to consumers from benthic algae is highly variable, and depends on a combination of consumer and resource movements, in addition to the trophic position of the consumer. [source] Contrasting paleofluid systems in the continental basement: a fluid inclusion and stable isotope study of hydrothermal vein mineralization, Schwarzwald district, GermanyGEOFLUIDS (ELECTRONIC), Issue 2 2007B. BAATARTSOGT Abstract An integrated fluid inclusion and stable isotope study was carried out on hydrothermal veins (Sb-bearing quartz veins, metal-bearing fluorite,barite,quartz veins) from the Schwarzwald district, Germany. A total number of 106 Variscan (quartz veins related to Variscan orogenic processes) and post-Variscan deposits were studied by microthermometry, Raman spectroscopy, and stable isotope analysis. The fluid inclusions in Variscan quartz veins are of the H2O,NaCl,(KCl) type, have low salinities (0,10 wt.% eqv. NaCl) and high Th values (150,350°C). Oxygen isotope data for quartz range from +2.8, to +12.2, and calculated ,18OH2O values of the fluid are between ,12.5, and +4.4,. The ,D values of water extracted from fluid inclusions vary between ,49, and +4,. The geological framework, fluid inclusion and stable isotope characteristics of the Variscan veins suggest an origin from regional metamorphic devolatilization processes. By contrast, the fluid inclusions in post-Variscan fluorite, calcite, barite, quartz, and sphalerite belong to the H2O,NaCl,CaCl2 type, have high salinities (22,25 wt.% eqv. NaCl) and lower Th values of 90,200°C. A low-salinity fluid (0,15 wt.% eqv. NaCl) was observed in late-stage fluorite, calcite, and quartz, which was trapped at similar temperatures. The ,18O values of quartz range between +11.1, and +20.9,, which translates into calculated ,18OH2O values between ,11.0, and +4.4,. This range is consistent with ,18OH2O values of fluid inclusion water extracted from fluorite (,11.6, to +1.1,). The ,D values of directly measured fluid inclusion water range between ,29, and ,1,, ,26, and ,15,, and ,63, and +9, for fluorite, quartz, and calcite, respectively. Calculations using the fluid inclusion and isotope data point to formation of the fluorite,barite,quartz veins under near-hydrostatic conditions. The ,18OH2O and ,D data, particularly the observed wide range in ,D, indicate that the mineralization formed through large-scale mixing of a basement-derived saline NaCl,CaCl2 brine with meteoric water. Our comprehensive study provides evidence for two fundamentally different fluid systems in the crystalline basement. The Variscan fluid regime is dominated by fluids generated through metamorphic devolatilization and fluid expulsion driven by compressional nappe tectonics. The onset of post-Variscan extensional tectonics resulted in replacement of the orogenic fluid regime by fluids which have distinct compositional characteristics and are related to a change in the principal fluid sources and the general fluid flow patterns. This younger system shows remarkably persistent geochemical and isotopic features over a prolonged period of more than 100 Ma. [source] Immunohistochemical analysis of heme oxygenase-1 in preneoplastic and neoplastic lesions during chemical hepatocarcinogenesis,INTERNATIONAL JOURNAL OF EXPERIMENTAL PATHOLOGY, Issue 4 2004Fabiana Caballero Summary Heme oxygenase (HO) breaks down the pro-oxidant heme into carbon monoxide, iron and the antioxidant biliverdin. The isoform HO-1 plays an effective role to counteract oxidative damage and to control inflammation. Prolonged cellular damage due to chronic inflammation is one of the reasons leading to the development of tumours. The aim of this work was to investigate HO-1 expression and localization along the different stages of chemically induced hepatocarcinogenesis (HCC) and the occurring morphological changes. To provoke sustained oxidative stress and chronic inflammation, CF1 mice received dietary p -dimethylaminoazobenzene (DAB, 0.5%, w/w) during a whole period of 14 months. HO-1 expression increased along the experimental trial in morphologically normal hepatocytes in DAB-treated animals. HO-1 expression diminished in altered hepatic foci (AHF) and oval cells and early preneoplastic lesions. Otherwise, marked HO-1 overexpression was detected in Kupffer cells and macrophages surrounding necrotic and nodular areas. Adenomas showed decreased HO-1 immunostaining. In hepatocellular carcinomas, an inverse relationship was found between the immunohistochemical expression of HO-1 and the degree of tumour differentiation, being negative in poorly differentiated tumours. In our experimental model, down modulation of HO-1 expression correlated with malignancy progression. Thus, our data point to activation of HO-1 as a potential therapeutic tool. [source] Fibres in the dough influencing freezing and thawing kineticsINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 1 2010Jelena Filipovic Summary Three types of commercial fibres were incorporated into the dough formula at the level of 0%, 5% and 10%. Dough freezing/thawing kinetics was determined at ,18 °C and +30 °C, respectively. Fibres type and quantity are influencing the slope of freezing curve not the trend of the freezing curve. Related to the control the presence of fibres in dough prevents the formation of the solid phase. Freezing/thawing process of dough is defined by the Fourier's equation and tested with three approximations. Experimental data correspond the best to unsteady temperature profile, with introduced value of t2 referring to the phase transformation, proved by determination coefficient. At freezing/thawing the highest determination coefficient is experienced with 10% of inulin GR (0.966 and 0.991), and the lowest with 10% of fibrex (0.939 and 0.972). Pertinent data point at the possibility of mathematical interpretation of freezing/thawing processes that is of a particular interest for the bakery practice. [source] Intracellular dynamics of Smad-mediated TGF, signalingJOURNAL OF CELLULAR PHYSIOLOGY, Issue 2 2003Robert M. Greene The transforming growth factor-, (TGF,) family represents a class of signaling molecules that plays a central role in morphogenesis, growth, and cell differentiation during normal embryonic development. Members of this growth factor family are particularly vital to development of the mammalian secondary palate where they regulate palate mesenchymal cell proliferation and extracellular matrix synthesis. Such regulation is particularly critical since perturbation of either cellular process results in a cleft of the palate. While the cellular and phenotypic effects of TGF, on embryonic craniofacial tissue have been extensively catalogued, the specific genes that function as downstream mediators of TGF, action in the embryo during palatal ontogenesis are poorly defined. Embryonic palatal tissue in vivo and murine embryonic palate mesenchymal (MEPM) cells in vitro secrete and respond to TGF,. In the current study, elements of the Smad component of the TGF, intracellular signaling system were identified and characterized in cells of the embryonic palate and functional activation of the Smad pathway by TGF,1, TGF,2, and TGF,3 was demonstrated. TGF,-initiated Smad signaling in cells of the embryonic palate was found to result in: (1) phosphorylation of Smad 2; (2) nuclear translocation of the Smads 2, 3, and 4 protein complex; (3) binding of Smads 3 and 4 to a consensus Smad binding element (SBE) oligonucleotide; (4) transactivation of transfected reporter constructs, containing TGF,-inducible Smad response elements; and (4) increased expression of gelatinases A and B (endogenous genes containing Smad response elements) whose expression is critical to matrix remodeling during palatal ontogenesis. Collectively, these data point to the presence of a functional Smad-mediated TGF, signaling system in cells of the developing murine palate. J. Cell. Physiol. 197: 261,271, 2003. © 2003 Wiley-Liss, Inc. [source] Infiltration anesthetic lidocaine inhibits cancer cell invasion by modulating ectodomain shedding of heparin-binding epidermal growth factor-like growth factor (HB-EGF)JOURNAL OF CELLULAR PHYSIOLOGY, Issue 3 2002Tadanori Mammoto Although the mechanism is unknown, infiltration anesthetics are believed to have membrane-stabilizing action. We report here that such a most commonly used anesthetic, lidocaine, effectively inhibited the invasive ability of human cancer (HT1080, HOS, and RPMI-7951) cells at concentrations used in surgical operations (5,20 mM). Ectodomain shedding of heparin-binding epidermal growth factor-like growth factor (HB-EGF) from the cell surface plays an important role in invasion by HT1080 cells. Lidocaine reduced the invasion ability of these cells by partly inhibiting the shedding of HB-EGF from the cell surface and modulation of intracellular Ca2+ concentration contributed to this action. The anesthetic action of lidocaine (sodium channel blocking ability) did not contribute to this anti-invasive action. In addition, lidocaine (5,30 mM), infiltrated around the inoculation site, inhibited pulmonary metastases of murine osteosarcoma (LM 8) cells in vivo. These data point to previously unrecognized beneficial actions of lidocaine and suggest that lidocaine might be an ideal infiltration anesthetic for surgical cancer operations. © 2002 Wiley-Liss, Inc. [source] Prediction of two-phase pressure drop and liquid holdup in co-current gas,liquid downflow of air,Newtonian systems through packed bedsJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 1 2006Ponnan Ettiyappan Jagadeesh Babu Abstract The dependency of pressure drop and liquid holdup on phase velocities, geometry of the column and packing materials as well as on the physical properties have been analyzed. Our experimental data (825 data points obtained using four liquid systems and three different particles) along with those of the available literature (776 data point from five different sources) were used for the analysis. The applicability and the limitations of the literature correlations were evaluated using the available data. Based on the analysis, new correlations for the estimation of pressure drop and liquid holdup, valid for low and high interaction regimes have been developed using the available data, with a wide range of variables. Copyright © 2005 Society of Chemical Industry [source] Mitochondrial DNA mutations as a fundamental mechanism in physiological declines associated with agingAGING CELL, Issue 1 2003Jeong W. Pak Summary The hypothesis that mitochondrial DNA damage accumulates and contributes to aging was proposed decades ago. Only recently have technological advancements, which facilitate microanalysis of single cells or portions of cells, revealed that mtDNA deletion mutations and, perhaps, single nucleotide mutations accumulate to physiologically relevant levels in the tissues of various species with age. Although a link between single nucleotide mutations and physiological consequences in aging tissue has not been established, the accumulation of deletion mutations in skeletal muscle fibres has been associated with sarcopenia. Different, and apparently random, deletion mutations are specific to individual fibres. However, the mtDNA deletion mutation within a phenotypically abnormal region of a fibre is the same, suggesting a selection, amplification and clonal expansion of the initial deletion mutation. mtDNA deletion mutations within a muscle fibre are associated with specific electron transport system abnormalities, muscle fibre atrophy and fibre breakage. These data point to a causal relationship between mitochondrial DNA mutations and the age-related loss of muscle mass. [source] Equations to predict precipitation onset and bubblepoint pressures of asphaltenic reservoir fluidsAICHE JOURNAL, Issue 7 2009J. M. del Rio Abstract A set of algebraic equations to predict upper onset-of-precipitation and bubble-point pressures of asphaltene-containing reservoir fluids in wide temperature ranges are proposed. In developing the equations, laboratory data of 11 Mexican and 12 more live oils have been analyzed, and a correlation of these data with temperature has been found. A modified least-squares regression method has been used to develop two versions of the proposed equations. In one version, a single pressure/temperature data point is required to predict the entire onset/bubble-point curves at any temperature. For oils with no experimental precipitation data available at all, a second version of the proposed expressions employs standard chromatographic data of the reservoir fluid to provide a reasonable prediction. The average absolute deviations in calculated onset and bubble-point pressures by the proposed equations are 2.53 and 0.45MPa by the one-point correlations, respectively, and 3.96 and 1.62 MPa by the compositionally-based correlations, respectively. The developed expressions are simple and can be used to provide reasonable predictions of upper onset and bubble-point pressures of asphaltenic live oils in cases where laboratory data are scarce. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Characterization and role of Helix contactin-related proteins in cultured Helix pomatia neuronsJOURNAL OF NEUROSCIENCE RESEARCH, Issue 2 2009C. Milanese Abstract We report on the structural and functional properties of the Helix contactin-related proteins (HCRPs), a family of closely related glycoproteins previously identified in the nervous system of the land snail Helix pomatia through antibodies against the mouse F3/contactin glycoprotein. We focus on HCRP1 and HCRP2, soluble FNIII domains-containing proteins of 90 and 45 kD bearing consensus motifs for both N- and O-glycosylation. Using the anti-HCRPs serum, we find secreted HCRPs in Helix nervous tissue isotonic extracts and in culture medium conditioned by Helix ganglia. In addition, we demonstrate expression of HCRPs on neuronal soma and on neurite extensions. Functionally, in Helix neurons, the antisense HCRP2 mRNA counteracts neurite elongation, and the recombinant HCRP2 protein exerts a strong positive effect on neurite growth when used as substrate. These data point to HCRPs as novel neurite growth-promoting molecules expressed in invertebrate nervous tissue. © 2008 Wiley-Liss, Inc. [source] A minor ,-structured conformation is the active state of a fusion peptide of vesicular stomatitis virus glycoprotein,JOURNAL OF PEPTIDE SCIENCE, Issue 4 2008Carolina G. Sarzedas Abstract Entry of enveloped animal viruses into their host cells always depends on a step of membrane fusion triggered by conformational changes in viral envelope glycoproteins. Vesicular stomatitis virus (VSV) infection is mediated by virus spike glycoprotein G, which induces membrane fusion at the acidic environment of the endosomal compartment. In a previous work, we identified a specific sequence in the VSV G protein, comprising the residues 145,164, directly involved in membrane interaction and fusion. In the present work we studied the interaction of pep[145,164] with membranes using NMR to solve the structure of the peptide in two membrane-mimetic systems: SDS micelles and liposomes composed of phosphatidylcholine and phosphatidylserine (PC:PS vesicles). The presence of medium-range NOEs showed that the peptide has a tendency to form N - and C -terminal helical segments in the presence of SDS micelles. Analysis of the chemical shift index indicated helix,coil equilibrium for the C -terminal helix under all conditions studied. At pH 7.0, the N -terminal helix also displayed a helix,coil equilibrium when pep[145-164] was free in solution or in the presence of PC:PS. Remarkably, at the fusogenic pH, the region of the N -terminal helix in the presence of SDS or PC:PS presented a third conformational species that was in equilibrium with the helix and random coil. The N -terminal helix content decreases pH and the minor ,-structured conformation becomes more prevalent at the fusogenic pH. These data point to a ,-conformation as the fusogenic active structure-which is in agreement with the X-ray structure, which shows a ,-hairpin for the region corresponding to pep[145-164]. Copyright © 2007 European Peptide Society and John Wiley & Sons, Ltd. [source] WELL LOG CALIBRATION OF KOHONEN-CLASSIFIED SEISMIC ATTRIBUTES USING BAYESIAN LOGICJOURNAL OF PETROLEUM GEOLOGY, Issue 4 2001M. T. Taner We present a new method for calibrating a classified 3D seismic volume. The classification process employs a Kohonen self-organizing map, a type of unsupervised artificial neural network; the subsequent calibration is performed using one or more suites of well logs. Kohonen self-organizing maps and other unsupervised clustering methods generate classes of data based on the identification of various discriminating features. These methods seek an organization in a dataset and form relational organized clusters. However, these clusters may or may not have any physical analogues in the real world. In order to relate them to the real world, we must develop a calibration method that not only defines the relationship between the clusters and real physical properties, but also provides an estimate of the validity of these relationships. With the development of this relationship, the whole dataset can then be calibrated. The clustering step reduces the multi-dimensional data into logically smaller groups. Each original data point defined by multiple attributes is reduced to a one- or two-dimensional relational group. This establishes some logical clustering and reduces the complexity of the classification problem. Furthermore, calibration should be more successful since it will have to consider less variability in the data. In this paper, we present a simple calibration method that employs Bayesian logic to provide the relationship between cluster centres and the real world. The output will give the most probable calibration between each self-organized map node and wellbore-measured parameters such as lithology, porosity and fluid saturation. The second part of the output comprises the calibration probability. The method is described in detail, and a case study is briefly presented using data acquired in the Orange River Basin, South Africa. The method shows promise as an alternative to current techniques for integrating seismic and log data during reservoir characterization. [source] Design and evaluation of a dry coated drug delivery system with floating,pulsatile releaseJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 1 2008Hao Zou Abstract The objective of this work was to develop and evaluate a floating,pulsatile drug delivery system intended for chronopharmacotherapy. Floating,pulsatile concept was applied to increase the gastric residence of the dosage form having lag phase followed by a burst release. To overcome limitations of various approaches for imparting buoyancy, we generated the system which consisted of three different parts, a core tablet, containing the active ingredient, an erodible outer shell and a top cover buoyant layer. The dry coated tablet consists in a drug-containing core, coated by a hydrophilic erodible polymer which is responsible for a lag phase in the onset of pulsatile release. The buoyant layer, prepared with Methocel® K4M, Carbopol® 934P and sodium bicarbonate, provides buoyancy to increase the retention of the oral dosage form in the stomach. The effect of the hydrophilic erodible polymer characteristics on the lag time and drug release was investigated. Developed formulations were evaluated for their buoyancy, dissolution and pharmacokinetic, as well gamma-scintigraphically. The results showed that a certain lag time before the drug released generally due to the erosion of the dry coated layer. Floating time was controlled by the quantity and composition of the buoyant layer. Both pharmacokinetic and gamma-scintigraphic data point out the capability of the system of prolonged residence of the tablets in the stomach and releasing drugs after a programmed lag time. © 2007 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 97:263,273, 2008 [source] Correlation of the rates of solvolysis of benzoyl chloride and derivatives using extended forms of the Grunwald,Winstein equation,JOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 12 2002Dennis N. Kevill Abstract Available specific rates of solvolysis at 25,°C of benzoyl chloride and four para -substituted derivatives for which both NT and YCl values are tabulated were analyzed using the extended (two-term) Grunwald,Winstein equation. The ionization pathway with appreciable nucleophilic solvation of the incipient carbocation observed for the p -methoxy derivative is accompanied by increasingly important regions of dominant operation of an addition,elimination pathway as the Hammett , value for the substituent increases. Accordingly, for the p -nitro derivative only the 97% HFIP data point deviates from the addition,elimination correlation. Correlations of the specific rates of solvolysis of 2,6-dimethylbenzoyl chloride are improved by incorporation of a term governed by the aromatic ring parameter (I). Copyright © 2002 John Wiley & Sons, Ltd. [source] Changing marine productivity off northern Chile during the past 19,000 years: a multivariable approachJOURNAL OF QUATERNARY SCIENCE, Issue 4 2004M. Mohtadi Abstract A multivariable approach utilising bulk sediment, planktonic Foraminifera and siliceous phytoplankton has been used to reconstruct rapid variations in palaeoproductivity in the Peru,Chile Current System off northern Chile for the past 19,000,cal.,yr. During the early deglaciation (19,000,16,000,cal.,yr,BP), our data point to strongest upwelling intensity and highest productivity of the past 19,000,cal.,yr. The late deglaciation (16,000,13,000,cal.,yr,BP) is characterised by a major change in the oceanographic setting, warmer water masses and weaker upwelling at the study site. Lowest productivity and weakest upwelling intensity are observed from the early to the middle Holocene (13,000,4000,cal.,yr,BP), and the beginning of the late Holocene (<4000,cal.,yr,BP) is marked by increasing productivity, mainly driven by silicate-producing organisms. Changes in the productivity and upwelling intensity in our record may have resulted from a large-scale compression and/or displacement of the South Pacific subtropical gyre during more productive periods, in line with a northward extension of the Antarctic Circumpolar Current and increased advection of Antarctic water masses with the Peru,Chile Current. The corresponding increase in hemispheric thermal gradient and wind stress induced stronger upwelling. During the periods of lower productivity, this scenario probably reversed. Copyright © 2004 John Wiley & Sons, Ltd. [source] Ischemic preconditioning attenuates the oxidant-dependent mechanisms of reperfusion cell damage and death in rat liverLIVER TRANSPLANTATION, Issue 11 2002Barbara Cavalieri In an in vivo rat model of liver ischemia followed by reperfusion a consistent appearance of necrosis and activation of biochemical pathways of apoptosis was reproduced and monitored after 30 minutes reperfusion. Preconditioning by application of a short cycle of ischemia-reperfusion (10 minutes + 10 minutes) positively conditioned recovery of the organ at reperfusion, attenuating both necrotic and apoptotic events. Preconditioning at least halved cell oxidative damage occurring early at reperfusion, and as a major consequence, the increase of cytolysis and apoptosis occurring at reperfusion was about 50% less. The attenuation of both pathways of cell death by preconditioning appeared at least partly related to its modulate action on H2O2 and 4-hydroxy-2,3-trans-nonenal production. The overall data point to a marked diminished oxidant generation and oxidative reactions as one major possible mechanism through which ischemic preconditioning exerts protection against necrotic and apoptotic insult to the postischemic liver. [source] Quantitative magnetization transfer mapping of bound protons in multiple sclerosisMAGNETIC RESONANCE IN MEDICINE, Issue 1 2003D. Tozer Abstract Quantitative analysis of magnetization transfer images has the potential to allow a more thorough characterization of the protons, both bound and free, in a tissue by extracting a number of parameters relating to the NMR properties of the protons and their local environment. This work develops previously presented techniques to produce estimates of parameters such as the bound proton fraction, f, and the transverse relaxation time of the bound pool, T2B, for the whole brain in a clinically acceptable imaging time. This is achieved by limiting the number of data collected (typically to 10); to collect 28 5-mm slices with a reconstructed resolution of 0.94 × 0.94 mm. The protocol takes 82 sec per data point. The fitting technique is assessed against previous work and for fitting failures. Maps and analysis are presented from a group of seven controls and 20 multiple sclerosis patients. The maps show that the parameters are sensitive to tissue-specific differences and can detect pathological change within lesions. Statistically significant differences in parameters such as T2B and f are seen between normal-appearing white matter, multiple sclerosis lesions, and control white matter. Whole-brain histograms of these parameters are also presented, showing differences between patients and controls. Magn Reson Med 50:83,91, 2003. © 2003 Wiley-Liss, Inc. [source] An international and multidisciplinary drilling project into a young complex impact structure: The 2004 ICDP Bosumtwi Crater Drilling Project,An overviewMETEORITICS & PLANETARY SCIENCE, Issue 4-5 2007Christian KOEBERL It is the source crater of the Ivory Coast tektites. The structure was excavated in 2.1,2.2 Gyr old metasediments and metavolcanics of the Birimian Supergroup. A drilling project was conceived that would combine two major scientific interests in this crater: 1) to obtain a complete paleoenvironmental record from the time of crater formation about one million years ago, at a near-equatorial location in Africa for which very few data are available so far, and 2) to obtain a complete record of impactites at the central uplift and in the crater moat, for ground truthing and comparison with other structures. Within the framework of an international and multidisciplinary drilling project led by the International Continental Scientific Drilling Program (ICDP), 16 drill cores were obtained from June to October 2004 at six locations within Lake Bosumtwi, which is 8.5 km in diameter. The 14 sediment cores are currently being investigated for paleoenvironmental indicators. The two impactite cores LB-07A and LB-08A were drilled into the deepest section of the annular moat (540 m) and the flank of the central uplift (450 m), respectively. They are the main subject of this special issue of Meteoritics & Planetary Science, which represents the first detailed presentations of results from the deep drilling into the Bosumtwi impactite sequence. Drilling progressed in both cases through the impact breccia layer into fractured bedrock. LB-07A comprises lithic (in the uppermost part) and suevitic impact breccias with appreciable amounts of impact melt fragments. The lithic clast content is dominated by graywacke, besides various metapelites, quartzite, and a carbonate target component. Shock deformation in the form of quartz grains with planar microdeformations is abundant. First chemical results indicate a number of suevite samples that are strongly enriched in siderophile elements and Mg, but the presence of a definite meteoritic component in these samples cannot be confirmed due to high indigenous values. Core LB-08A comprises suevitic breccia in the uppermost part, followed with depth by a thick sequence of graywacke-dominated metasediment with suevite and a few granitoid dike intercalations. It is assumed that the metasediment package represents bedrock intersected in the flank of the central uplift. Both 7A and 8A suevite intersections differ from suevites outside of the northern crater rim. Deep drilling results confirmed the gross structure of the crater as imaged by the pre-drilling seismic surveys. Borehole geophysical studies conducted in the two boreholes confirmed the low seismic velocities for the post-impact sediments (less than 1800 m/s) and the impactites (2600,3300 m/s). The impactites exhibit very high porosities (up to 30 vol%), which has important implications for mechanical rock stability. The statistical analysis of the velocities and densities reveals a seismically transparent impactite sequence (free of prominent internal reflections). Petrophysical core analyses provide no support for the presence of a homogeneous magnetic unit (= melt breccia) within the center of the structure. Borehole vector magnetic data point to a patchy distribution of highly magnetic rocks within the impactite sequence. The lack of a coherent melt sheet, or indeed of any significant amounts of melt rock in the crater fill, is in contrast to expectations from modeling and pre-drilling geophysics, and presents an interesting problem for comparative studies and requires re-evaluation of existing data from other terrestrial impact craters, as well as modeling parameters. [source] Involvement of Clp protease activity in modulating the Bacillus subtilis,W stress responseMOLECULAR MICROBIOLOGY, Issue 6 2006Stephan Zellmeier Summary The induction of Bacillus subtilis genes controlled by the extracytoplasmic function alternative sigma factor ,W is strongly impaired in a strain deleted for the ClpP peptidase gene and in a double knockout of the ClpX and ClpE ATPase genes. Truncated soluble forms of the ,W anti-sigma factor RsiW are stabilized in a clpP minus strain as revealed by the green fluorescent reporter protein fused to the N-terminus of RsiW and by pulse-chase experiments. Conserved alanine residues are present in the transmembrane region of RsiW, and mutations in these positions abolish induction of ,W -controlled genes. Following alkaline shock, a truncated cytoplasmic form of RsiW is detectable in a strain expressing a triple alanine mutant allele of rsiW. These data point to a mechanism where the trans -membrane segment of RsiW contains a cryptic proteolytic tag that is uncovered as a result of intramembrane proteolysis of RsiW by RasP (YluC). After RasP-clipped RsiW is detached from the membrane, this proteolytic tag becomes crucial for the complete degradation of RsiW by cytoplasmic proteases and the release of ,W. ClpXP plays a major role in this third proteolytic step of stress-induced degradation of RsiW. Overexpression of SsrA-tagged green fluorescent protein as a ClpXP substrate protein reduces alkali induction of a ,W -controlled gene by a factor of about three, indicating that a titration mechanism is able to tune the ,W -mediated stress response to the cellular state. [source] Isochrone ages for field dwarfs: method and application to the age,metallicity relationMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 2 2004Frédéric Pont ABSTRACT A new method is presented to compute age estimates from theoretical isochrones using temperature, luminosity and metallicity data for individual stars. Based on Bayesian probability theory, this method avoids the systematic biases affecting simpler strategies and provides reliable estimates of the age probability distribution function for late-type dwarfs. Basic assumptions concerning the a priori parameter distribution suitable for the solar neighbourhood are combined with the likelihood assigned to the observed data to yield the complete posterior age probability. This method is especially relevant for G dwarfs in the 3,15 Gyr range of ages, crucial to the study of the chemical and dynamical history of the Galaxy. In many cases, it yields markedly different results from the traditional approach of reading the derived age from the isochrone nearest to the data point. We show that the strongest process affecting the traditional approach is that of strongly favouring computed ages near the end-of-main-sequence lifetime. The Bayesian method compensates for this potential bias and generally assigns much higher probabilities to lower main-sequence ages, compared with short-lived evolved stages. This has a strong influence on any application to galactic studies, especially given the present uncertainties on the absolute temperature scale of the stellar evolution models. In particular, the known mismatch between the model predictions and the observations for moderately metal-poor dwarfs (,1 < [Fe/H] < ,0.3) has a dramatic effect on the traditional age determination. We apply our method to the classic sample of Edvardsson et al., who derived the age,metallicity relation (AMR) of 189 field dwarfs with precisely determined abundances. We show how much of the observed scatter in the AMR is caused by the interplay between the systematic biases affecting the traditional age determination, the colour mismatch with the evolution models and the presence of undetected binaries. Using new parallax, temperature and metallicity data, our age determination for the same sample indicates that the intrinsic dispersion in the AMR is at most 0.15 dex and probably lower. In particular, we show that old, metal-rich objects ([Fe/H], 0.0 dex, age > 5 Gyr) and young, metal-poor objects ([Fe/H] < ,0.5 dex, age < 6 Gyr) in many observed AMR plots are artefacts caused by too simple a treatment of the age determination. The incompatibility of those AMR plots with a well-mixed interstellar medium may therefore only be apparent. Incidentally, our results tend to restore confidence in the method of age determination from the chromospheric activity for field dwarfs. [source] Familial cortical myoclonic tremor with epilepsy: A single syndromic classification for a group of pedigrees bearing common featuresMOVEMENT DISORDERS, Issue 6 2005Anne-Fleur Van Rootselaar MD Abstract Fifty Japanese and European families with cortical myoclonic tremor and epilepsy have been reported under various names. Unfamiliarity with the syndrome often leads to an initial misdiagnosis of essential tremor or progressive myoclonus epilepsy. A detailed overview of the literature is lacking and is the scope of this study. Disease characteristics are adult onset, distal action tremor and myoclonus, epileptic seizures, autosomal dominant inheritance, benign course, effectiveness of antiepileptic drugs, and possibly cognitive decline. A channelopathy is hypothesized to be the basis of the disease. Despite phenotypic and genetic differences between the Japanese and European pedigrees, the clinical and electrophysiological data point toward one syndrome. To avoid confusion in literature and possible misdiagnosis of patients, we propose to use one description and suggest "familial cortical myoclonic tremor with epilepsy" (FCMTE). In addition, we put forward diagnostic criteria to give a starting point from which to conduct genetic studies. © 2005 Movement Disorder Society [source] Daily differences in patterns of physical activity among overweight/obese children engaged in a physical activity programAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 6 2007Luísa Aires The aim of this study was to compare the physical activity of overweight/obese children during days when they attended a physical activity program, and days when they did not. This is a cross-sectional intervention study of daily physical activity. The participants were referred by family, doctors, or hospital pediatricians to take part in a 10-month interdisciplinary, outpatient obesity intervention program for children. The subjects included 41 overweight and obese children aged 8,16 years, 19 boys (46%) and 22 girls (54%); BMI: 25.7 + 3.3 kg m,2. The MTI Actigraph was used as an objective measure of daily physical activity over seven consecutive days. Physical activity program days presented a significantly higher percentage of time (4.68%) spent in moderate-to-vigorous activity compared with no physical activity program days (3.16%) and weekend (2.7%). The results of this study suggest that a physical activity program can help increasing daily physical activity in obese children, with a special focus on MVPA level. Our data point that obese children are less active at weekend than during weekdays. Am. J. Hum. Biol., 2007. © 2007 Wiley-Liss, Inc. [source] Activity against drug resistant-tuberculosis strains of plants used in Mexican traditional medicine to treat tuberculosis and other respiratory diseasesPHYTOTHERAPY RESEARCH, Issue 1 2008María del Rayo Camacho-Corona Abstract Tuberculosis (TB) kills about 3 million people per year worldwide. Furthermore, TB is an infectious disease associated with HIV patients, and there is a rise in multidrug-resistant TB (MDR-TB) cases around the world. There is a need for new anti-TB agents. The study evaluated the antimycobacterial activity of nine plants used in Mexican traditional medicine to treat tuberculosis and other respiratory diseases. Nasturtium officinale showed the best activity (MIC = 100 µg/mL) against the sensitive Mycobacterium tuberculosis. The following plants were active also but at 200 µg/mL: Citrus sinensis, Citrus aurantifolia, Foeniculum vulgare, Larrea tridentata, Musa acuminata and Olea europaea. Contrary to the above data, activity against drug-resistant variants of M. tuberculosis was more evident, e.g. N. officinale was the most potent (MIC , 100 µg/mL) against the four mono-resistant variants tested; F. vulgare and O. europaea were active against all the resistant variants (MICs , 100 µg/mL). The most susceptible variant was the isoniazid resistant, being inhibited by C. aurantifolia, C. sinensis and O. europaea (MIC = 25 µg/mL). These data point to the importance of biological testing of extracts against drug-resistant M. tuberculosis isolates, and the bioguided assay of these extracts for the identification of lead compounds against MDR-TB isolates. Copyright © 2007 John Wiley & Sons, Ltd. [source] Wnt/frizzled family members mediate olfactory sensory neuron axon extensionTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 3 2008Diego J. Rodriguez-Gil Abstract A comprehensive model has yet to emerge, but it seems likely that numerous mechanisms contribute to the specificity of olfactory sensory neuron (OSN) axon innervation of the olfactory bulb. Elsewhere in the nervous system the Wnt/Fz family has been implicated in patterning of anterior-posterior axes, cell type specification, cell proliferation, and axon guidance. Because of our work describing cadherin-catenin family member expression in the primary olfactory pathway, and because mechanisms of Wnt-Fz interactions can depend in part on catenins, we were encouraged to explore Wnt-Fz expression and function in OSN axon extension. Here, we show that OSNs express Fz-1, Fz-3, and Wnt-5a, whereas olfactory ensheathing cells (OECs) express Wnt-4. Fz-7 is also expressed in the olfactory nerve by cells that delineate large axon fascicles, but are negative for OEC markers. Fz-1 showed a developmental downregulation. However, in adults it is expressed at different levels across the olfactory epithelium and in restricted glomeruli across the olfactory bulb, suggesting an important role in the formation and maintenance of OSN connections to the olfactory bulb. Reporter TOPGAL mice demonstrated that some OECs located in the inner olfactory nerve layer can respond to Wnt ligands. Of further interest, we show here with in vitro assays that Wnt-5a increases OSN axon outgrowth and alters growth cone morphology. Our data point to a key role for Wnt/Fz molecules in the development of the mouse olfactory system, providing complementary mechanisms required for OSN axon extension and coalescence. J. Comp. Neurol. 511:301,317, 2008. © 2008 Wiley-Liss, Inc. [source] Long-Term Performance of Clarion 1.0 Cochlear Implant Users,THE LARYNGOSCOPE, Issue 7 2007Chad V. Ruffin BS Abstract Objective/Hypothesis: To evaluate the long-term performance of adult Clarion 1.0 cochlear implant users. Study Design: This was a retrospective, longitudinal study evaluating word discrimination in quiet for 31 adult cochlear implant patients with preimplantation sentence scores of less than 10%. Methods: The length of the study was 135 months with a mean follow-up length of 93 (median, 96) months. For the duration of the study, all subjects used the Clarion 1.0 cochlear implant with speech processors programmed for the use of the continuous interleaved sampling strategy. Results: There was no significant growth or decline in speech perception after 24 months postimplantation unless adverse medical events were experienced. Age at implantation was significantly and substantially negatively correlated (,11% word score per decade, r = 0.68) with most recent score, maximum score, time to maximum score, range of performance, 24- to 130-month mean score, and for any longitudinal data point tested: 3 to 6 months, 6 months, 1 year, 2 years, 5 years, and 10 years. There were no age-related declines in performance. There were no observed correlations between duration of deafness and any of the variables listed above. Conclusions: The lack of correlation between duration of deafness and performance in a cohort without residual hearing suggests the presence of a strong correlation between age and speech performance with a cochlear implant. That the cochlear implant is a safe therapy for the treatment of profound deafness is supported by the stability of scores through the 10-year study period as well as a zero rate of device failures or explantation. [source] | ||||||||||||||||||||||||||||||||||||||||