Distribution by Scientific Domains
Distribution within Chemistry

Kinds of Selective

  • highly selective
  • very selective

  • Terms modified by Selective

  • selective abortion
  • selective accumulation
  • selective action
  • selective activation
  • selective activity
  • selective addition
  • selective adsorption
  • selective advantage
  • selective aerobic oxidation
  • selective agent
  • selective agonist
  • selective amplification
  • selective analysis
  • selective antagonist
  • selective antibody
  • selective application
  • selective approach
  • selective assembly
  • selective association
  • selective attachment
  • selective attention
  • selective autophagy
  • selective binding
  • selective blocker
  • selective breeding
  • selective breeding program
  • selective capture
  • selective catalyst
  • selective catalytic reduction
  • selective cerebral perfusion
  • selective change
  • selective channel
  • selective cleavage
  • selective coding
  • selective compound
  • selective constraint
  • selective control
  • selective conversion
  • selective coronary angiography
  • selective cox-2 inhibitor
  • selective culture media
  • selective cyclization
  • selective cyclooxygenase
  • selective cytotoxicity
  • selective damage
  • selective death
  • selective decrease
  • selective deficit
  • selective degeneration
  • selective depletion
  • selective deposition
  • selective deprotection
  • selective destruction
  • selective detection
  • selective detector
  • selective determination
  • selective differentiation
  • selective digestive decontamination
  • selective dimerization
  • selective disclosure
  • selective dissolution
  • selective downregulation
  • selective drug
  • selective effect
  • selective effects
  • selective electrode
  • selective elimination
  • selective enhancement
  • selective enrichment
  • selective environment
  • selective estrogen receptor modulator
  • selective expansion
  • selective exposure
  • selective expression
  • selective extinction
  • selective extraction
  • selective factor
  • selective feeding
  • selective filter
  • selective force
  • selective formation
  • selective functionalization
  • selective genotyping
  • selective grazing
  • selective growth
  • selective heating
  • selective herbicide
  • selective hydrogenation
  • selective hydrolysis
  • selective identification
  • selective imaging
  • selective impairment
  • selective inactivation
  • selective inclusion
  • selective increase
  • selective induction
  • selective inhibition
  • selective inhibitor
  • selective involvement
  • selective isolation
  • selective killing
  • selective laser sintering
  • selective lesion
  • selective ligand
  • selective literature review
  • selective logging
  • selective loss
  • selective manner
  • selective marker
  • selective mechanism
  • selective media
  • selective medium
  • selective mek inhibitor
  • selective membrane
  • selective memory
  • selective method
  • selective mortality
  • selective neck dissection
  • selective neurodegeneration
  • selective neuronal vulnerability
  • selective neutrality
  • selective nsaid
  • selective oxidation
  • selective pattern
  • selective patterning
  • selective precipitation
  • selective predation
  • selective preparation
  • selective preservation
  • selective pressure
  • selective process
  • selective protection
  • selective radioligand
  • selective reaction
  • selective receptor antagonist
  • selective recognition
  • selective recovery
  • selective recruitment
  • selective reduction
  • selective reflection
  • selective regime
  • selective release
  • selective removal
  • selective response
  • selective review
  • selective route
  • selective sampling
  • selective search
  • selective separation
  • selective serotonin re-uptake inhibitor
  • selective serotonin reuptake inhibitor
  • selective solvent
  • selective substrate
  • selective sweep
  • selective synthesis
  • selective target
  • selective targeting
  • selective toxicity
  • selective transformation
  • selective treatment
  • selective uptake
  • selective use
  • selective vulnerability

  • Selected Abstracts

    Relaxant effects of , -adrenergic agonists on porcine and human detrusor muscle

    ACTA PHYSIOLOGICA, Issue 2 2005
    J. K. Badawi
    Abstract Aim:, Relaxant effects of different , -adrenoceptor agonists on porcine and human detrusor were examined. Thus, the , -adrenoceptor subtype mainly responsible for relaxation in the detrusor muscle of pigs was characterized. Additionally, different effects of several , -agonists in both species were shown. Methods:, Experiments were performed on muscle strips of porcine and human detrusor suspended in a tissue bath. The relaxant effects of the non-selective , -agonist isoprenaline, the selective ,2-agonists procaterol, salbutamol and the selective ,3-agonists BRL 37344, CL 316 243 and CGP 12177 on potassium-induced contraction were investigated. The inhibitory effect of different substances on the maximum contraction and the rank order of potency for endogenous catecholamines was determined in pigs. Furthermore, concentration-relaxation curves were performed for pigs and humans. Results:,Pigs: In the pre-treatment experiments isoprenaline and procaterol showed similar effects. The concentration,response experiments showed that the maximum relaxation induced by procaterol and salbutamol was more than 90%, not significantly different from isoprenaline, whereas the maximum relaxations of CL 316 243, BRL 37344 and CGP 12177 amounted to 68, 70 or 30%, respectively. Rank order of potencies was isoprenaline , adrenaline > noradrenaline. Humans: Isoprenaline, procaterol, salbutamol and CL 316 243 showed a maximum relaxation of 80, 41, 24 and 35% and pD2 values of 6.24, 5.65, 5.48 and 5.55, respectively. Conclusion:,,2-receptors play a main functional role in mediating relaxation of porcine detrusor. Selective ,2- and ,3-agonists similarly relax the human detrusor. Effects were smaller compared with the pig. [source]

    Channel Strategies and Stocking Policies in Uncapacitated and Capacitated Supply Chains,

    DECISION SCIENCES, Issue 2 2002
    Jayashree Mahajan
    ABSTRACT A supply chain consisting of a single supplier distributing two independent products through multiple retailers is analyzed in this paper. The supplier needs to incentivize its retailers to adopt stocking policies that are mutually advantageous and that result in the optimal level of market coverage. The focus is on determining the optimal stocking policies for retailers and the resulting distribution strategy given that the supplier has either unlimited or limited capacity. The results provide insights on the optimal distribution strategy and stocking policies for the supply chain. In general, the paper shows that it is optimal for the supplier to use an intensive distribution strategy (i.e., the products are stocked by all retailers). Selective or exclusive strategies are optimal only when retailers are risk averse, stocking synergies exist, and there are differences in demand or supply uncertainties across products. The analysis also shows that retailers hold larger stocks of a product which generates higher supplier margins but only when the supplier has unlimited capacity. If the supplier has limited capacity, then their margins have no effect on retailers' stocking decisions. Contrary to conventional wisdom, retailers hold larger stocks of a product that has less demand uncertainty as compared to one that has more demand uncertainty. [source]

    Highly Selective and Sensitive Tin(II) Membrane Electrode Based on a New Synthesized Schiff's Base

    ELECTROANALYSIS, Issue 7 2009
    Morteza Hosseini
    Abstract Studies on complex formation of tris(3-(2-hydroxybenzophenone)propyl)amine (THPA) with a number of metal ions in acetonitrile solution revealed the occurrence of a selective 1,:,1 complexation of the proposed ligand with Sn2+ ion. Consequently, THPA was used as a suitable neutral ionophore for the preparation of a polymeric membrane-selective electrode. The electrode exhibits a Nernstian behavior with a slope of 29.4±0.3,mV per decade and a detection limit of 2.0×10,7 M. It also showed a good selectivity for Sn2+ ions in comparison with some of group A and B metal ions over a wide concentration range of 5.0×10,7,1.0×10,1 M. Improved selectivity was achieved compared to the best selectivity recently reported by other authors for tin(II). The electrode was successfully applied to the determination of Sn2+ ion in waste water and various canned products. [source]

    Selective and frequency dependent predation of aquatic mosquito predator Diplonychus indicus Venkatesan & Rao (Hemiptera: Belostomatidae) on immature stages of three mosquito species

    Narayanasamy SIVAGNANAME
    Abstract Frequency dependent mosquito larval size (II and IV instars) and species selection by the water bug Diplonychus indicus against three mosquito species Culex quinquefasciatus, Aedes aegypti and Anopheles stephensi was studied in the laboratory. The different frequencies used for each species selection were 20:30:50, 30:50:20, 50:20:30, 25:35:40, 35:40:25 and 40:25:35 of fourth instars of the respective three prey species. All nymphal water bugs (I,V instars) selected IV instar mosquito larvae and the mean proportion of late (larger) larvae eaten by the predator instars was significantly higher than the mean proportion of early (smaller) larvae eaten (F= 2.28; P < 0.001). In all six ratios used to determine the frequency dependent mosquito species selection, all the stages of the water bug selected Ae. aegypti over the other two species (F= 452.43; P < 0.001). The mean number of mosquito larvae eaten increased as its density increased based on various ratios of larvae offered. The study indicated that the predatory efficiency of D. indicus was high when Ae. aegypti was offered as prey, suggesting the utility of this mosquito predator in the control of dengue vectors. [source]

    Electrophysiological characterization of interlaminar entorhinal connections: an essential link for re-entrance in the hippocampal,entorhinal system

    Fabian Kloosterman
    Abstract The hippocampal formation communicates with the neocortex mainly through the adjacent entorhinal cortex. Neurons projecting to the hippocampal formation are found in the superficial layers of the entorhinal cortex and are largely segregated from the neurons receiving hippocampal output, which are located in deep entorhinal layers. We studied the communication between deep and superficial entorhinal layers in the anaesthetized rat using field potential recordings, current source density analysis and single unit measurements. We found that subiculum stimulation was able to excite entorhinal neurons in deep layers. This response was followed by current sinks in superficial layers. Both responses were subject to frequency dependent facilitation, but not depression. Selective blockade of deep layer responses also abolished subsequent superficial layer responses. This clearly demonstrates a functional deep-to-superficial layer communication in the entorhinal cortex, which can be triggered by hippocampal output. This pathway may provide a means by which processed hippocampal output is integrated or compared with new incoming information in superficial entorhinal layers, and it constitutes an important link in the process of re-entrance of activity in the hippocampal,entorhinal network, which may be important for consolidation of memories or retaining information for short periods. [source]

    Mechanism of Selective and Unselective Enclathration by a Host Compound Possessing Open, Flexible Host Frameworks

    Kazunori Nakano
    Abstract Molecular recognition of o -, m -, and p -xylenes (oX, mX, and pX) through enclathration of cholic acid (CA) is described. All of the xylenes give lattice inclusion crystals with CA, and crystallographic studies reveal that they are included in different open host frameworks. In particular, oX has two polymorphs, depending on the recrystallization temperatures. Competitive recrystallization from mixtures of xylenes resulted in selective enclathrations and the formation of racemic mixed crystals. In the presence of an equimolar amount of oX, CA selectively includes mX or pX in the host frameworks, which are identical to those obtained from the pure mX or pX, respectively. The low affinity of oX is explained in terms of a lower stability of CA·oX than of the other two complexes, as judged from the low PCcavity, the volume ratio of the guest compound to the host cavity. Meanwhile, mixtures of mX and pX yield inclusion crystals that accommodate both of the guests. These have the same open host framework as obtained from pure mX, and the guest components are disordered statically in the host cavity. The ratios of the xylene mixtures in the single crystals are similar to those in the original recrystallization mixtures, and also in the bulk crystals, indicating that CA forms mixed crystals of mX and pX. This non-selectivity is attributed to the similar stabilities of CA·mX and CA·pX, according to the moderate PCcavity. The inclusion behavior of CA from mixtures of xylenes is quite similar to chiral recognition by diastereomer-salt methods. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source]

    Cu(II)-Azabis(oxazoline)-Complexes Immobilized on Superparamagnetic Magnetite@Silica-Nanoparticles: A Highly Selective and Recyclable Catalyst for the Kinetic Resolution of 1,2-Diols

    Alexander Schätz
    Abstract Two different types of azide functionalized magnetite@silica nanoparticles are synthesized, which are ideally suited as inexpensive supports for catalysts and reagents as demonstrated with the grafting of copper(II)-azabis(oxazoline) complexes via a copper(I) catalyzed azide/alkyne cycloaddition (CuAAC) reaction. The potential of the immobilized complexes as catalysts is tested in the desymmetrization of racemic 1,2-diols through asymmetric benzoylation. Compared to azabis(oxazolines) "clicked" to common polymeric supports such as MeOPEG or Merrifield resin, Fe3O4@SiO2 proves to be superior with respect to activity and selectivity, as exemplified by employing the catalysts in up to five runs with consistent high activity and selectivity. Recycling of the catalysts is achieved quantitatively by magnetic decantation. [source]

    Mercury Biosensors: Polydiacetylene,Liposome Microarrays for Selective and Sensitive Mercury(II) Detection (Adv. Mater.

    ADVANCED MATERIALS, Issue 36 2009
    Polydiacetylene (PDA) liposome microarrays have been developed for selective and sensitive mercury detection. The sensors, reported on p. 3674 by Jinsang Kim and co-workers, are designed to produce red fluorescence emission upon binding with Hg2+; when the single-stranded DNA aptamers on the microarray selectively wrap around the mercury ions, the resulting complexes repulse each other. The epoxy-based PDA liposome design is an excellent universal platform that can be readily extended to other sensor designs. [source]

    Polydiacetylene,Liposome Microarrays for Selective and Sensitive Mercury(II) Detection

    ADVANCED MATERIALS, Issue 36 2009
    Jiseok Lee
    Polydiacetylene (PDA) liposome microarrays are developed for selective and sensitive mercury (Hg2+) detection. The PDA mercury sensors are designed to produce red fluorescence emission upon binding with Hg2+, when the ssDNA aptamers on the PDA surface recognize and wrap around mercury ions and the resulting bulky T-Hg-T complexes repulse each other. [source]

    Selective cyclooxygenase-2 inhibitor downregulates the paracrine epithelial,mesenchymal interactions of growth in scirrhous gastric carcinoma

    Masakazu Yashiro
    Abstract The importance of cancer-mesenchymal interactions in the aggressive behavior of scirrhous gastric cancer is supported by experimental and clinical evidences. We have previously reported that gastric fibroblasts secretion of keratinocyte growth factor (KGF) underline the remarkable proliferation of scirrhous gastric cancer cells. Cyclooxygenase-2 (COX-2) is not only expressed in cancer cells, but also in interstitial fibroblasts in gastric carcinoma. To clarify the mechanisms responsible for the antiproliferation effect of COX-2 inhibitors, effect of COX-2 inhibitor on the paracrine epithelial,mesenchymal interactions of growth was examined. Scirrhous gastric cancer cell line, OCUM-2M, gastric fibroblasts, NF-21, and COX-2 inhibitor, JTE-522, were used. Growth-interaction was examined by calculating the number of cancer cells or by measuring [3H] thymidine incorporation of cancer cells. Effect of JTE-522 on KGF expression from NF-21 cells and OCUM-2M cells was analyzed by ELISA and RT-PCR. The conditioned medium from gastric fibroblasts significantly stimulated the growth of scirrhous gastric cancer cells. JTE-522 at the concentrations of 10,5 and 10,6 M significantly decreased the growth-stimulating activity of gastric fibroblasts. JTE-522 reduced the expression of KGF mRNA and the production of KGF from gastric fibroblasts. Oral administration of JTE-522 significantly decreased the size of xenografted tumor coinoculated with OCUM-2M cells and NF-21 cells in nude mice. JTE-522 decreased COX-2 expression and Ki67 labeling index within the coinoculated tumor. These findings suggested that a selective COX-2 inhibitor, JTE-522, downregulates KGF production from gastric fibroblasts, resulting in the inhibition of paracrine epithelial,mesenchymal interactions of proliferation between scirrhous gastric cancer cells and gastric fibroblasts. © 2006 Wiley-Liss, Inc. [source]

    Crosslinked Bicontinuous Cubic Lyotropic Liquid-Crystal/Butyl-Rubber Composites: Highly Selective, Breathable Barrier Materials for Chemical Agent Protection,

    ADVANCED MATERIALS, Issue 24 2006
    X. Lu
    A breathable material that can act as a barrier to chemical agents is presented. The material is composed of butyl rubber and a crosslinkable lyotropic liquid crystal. Under the right synthesis conditions, a cubic phase with the desired selectivity properties results (see figure). The material is highly permeable to water vapor, but strongly impermeable to a mustard gas simulant. Application of the material for effective personal protection against such chemical agents is envisaged. [source]

    A Selective and Benign Synthesis of Functionalized Benzalacetones via Mizoroki,Heck Reaction Using Aryldiazonium Salts

    Therese Stern
    Abstract Palladium-catalyzed Mizoroki,Heck reactions were carried out in the presence of calcium carbonate in alcoholic solvents. Under these conditions an efficient preparation of functionalized benzalacetones was developed. The reactions were carried out at room temperature and aerobic conditions, giving the products within several minutes in up to 95% isolated yields. Furthermore, some kinetic investigations, mechanistic insights and considerations are presented. [source]

    A Highly Selective, Polymer-Supported Organocatalyst for Michael Additions with Enzyme-Like Behavior

    Esther Alza
    Abstract A polymer-supported ,,,-diarylprolinol silyl ether displays catalytic activity and enantioselectivity comparable to the best homogeneous catalysts in the Michael addition of aldehydes to nitroolefins. Above all, the combination of polymer backbone, triazole linker, and catalytic unit confers to it an unprecedented substrate selectivity in favor of linear, short-chain aldehydes. [source]

    Reasons for Being Selective When Choosing Personnel Selection Procedures

    Cornelius J. König
    The scientist,practitioner gap in personnel selection is large. Thus, it is important to gain a better understanding of the reasons that make organizations use or not use certain selection procedures. Based on institutional theory, we predicted that six variables should determine the use of selection procedures: the procedures' diffusion in the field, legal problems associated with the procedures, applicant reactions to the procedures, their usefulness for organizational self-promotion, their predictive validity, and the costs involved. To test these predictions, 506 HR professionals from the German-speaking part of Switzerland filled out an online survey on the selection procedures used in their organizations. Respondents also evaluated five procedures (semi-structured interviews, ability tests, personality tests, assessment centers, and graphology) on the six predictor variables. Multilevel logistic regression was used to analyze the data. The results revealed that the highest odd ratios belonged to the factors applicant reactions, costs, and diffusion. Lower (but significant) odds ratios belonged to the factors predictive validity, organizational self-promotion, and perceived legality. [source]

    Bismuth-Doped Ceria, Ce0.90Bi0.10O2: A Selective and Stable Catalyst for Clean Hydrogen Combustion

    Jurriaan Beckers
    Abstract Bismuth-doped cerias are successfully applied as solid "oxygen reservoirs" in the oxidative dehydrogenation of propane. The lattice oxygen of the ceria is used to selectively combust hydrogen from the dehydrogenation mixture at 550,°C. This process has three key advantages: it shifts the dehydrogenation equilibrium to the desired products side, generates heat, aiding the endothermic dehydrogenation, and simplifies product separation (water vs. hydrogen). Furthermore, the process is safer, since it uses the catalyst's lattice oxygen instead of gaseous oxygen. We show here that bismuth-doped cerias are highly active and stable towards hydrogen combustion, and explore four different approaches for optimising their application in the oxidative dehydrogenation of propane: first, the addition of extra hydrogen which lowers hydrocarbon conversion by suppressing both combustion and coking; second, the addition of tin which completely inhibits coking; third, the addition of platinum which increases selectivity, but at the expense of lower activity. The best results are obtained through tuning the reaction temperature. At 400,°C, high activity and selectivity were obtained for the bismuth-doped ceria Ce0.90Bi0.10O2. Here, 90% of the hydrogen feed is converted at 98% selectivity. This optimal reaction temperature can be rationalised from the hydrogen and propene temperature-programmed reduction (TPR) profiles: 400,°C lies above the reduction maximum of hydrogen, yet below that of propene. That is, this temperature is sufficiently high to facilitate rapid hydrogen combustion, but low enough to prevent hydrocarbon conversion. [source]

    Selective Blockade of Voltage-Gated Potassium Channels Reduces Inflammatory Bone Resorption in Experimental Periodontal Disease,,

    Paloma Valverde
    Abstract The effects of the potassium channel (Kv1.3) blocker kaliotoxin on T-cell-mediated periodontal bone resorption were examined in rats. Systemic administration of kaliotoxin abrogated the bone resorption in conjunction with decreased RANKL mRNA expression by T-cells in gingival tissue. This study suggests a plausible therapeutic approach for inflammatory bone resorption by targeting Kv1.3. Introduction: Kv1.3 is a critical potassium channel to counterbalance calcium influx at T-cell receptor activation. It is not known if Kv1.3 also regulates RANKL expression by antigen-activated T-cells, and consequently affects in vivo bone resorption mediated by activated T-cells. Materials and Methods:Actinobacillus actinomycetemcomitans 29-kDa outer membrane protein-specific Th1-clone cells were used to evaluate the expression of Kv1.3 (using reverse transcriptase-polymerase chain reaction [RT-PCR] and Western blot analyses) and the effects of the potassium channel blocker kaliotoxin (0,100 nM) on T-cell activation parameters ([3H]thymidine incorporation assays and ELISA) and expression of RANKL and osteoprotegerin (OPG; flow cytometry, Western blot, and RT-PCR analyses). A rat periodontal disease model based on the adoptive transfer of activated 29-kDa outer membrane protein-specific Th1 clone cells was used to analyze the effects of kaliotoxin in T-cell-mediated alveolar bone resorption and RANKL and OPG mRNA expression by gingival T-cells. Stimulated 29-kDa outer membrane protein-specific Th1 clone cells were transferred intravenously on day 0 to all animals used in the study (n = 7 animals per group). Ten micrograms of kaliotoxin were injected subcutaneously twice per day on days 0, 1, 2, and 3, after adoptive transfer of the T-cells. The control group of rats was injected with saline as placebo on the same days as injections for the kaliotoxin-treated group. The MOCP-5 osteoclast precursor cell line was used in co-culture studies with fixed 29-kDa outer membrane protein-specific Th1-clone cells to measure T-cell-derived RANKL-mediated effects on osteoclastogenesis and resorption pit formation assays in vitro. Statistical significance was evaluated by Student's t -test. Results: Kaliotoxin decreased T-cell activation parameters of 29-kDa outer membrane protein-specific Th1 clone cells in vitro and in vivo. Most importantly, kaliotoxin administration resulted in an 84% decrease of the bone resorption induced in the saline-treated control group. T-cells recovered from the gingival tissue of kaliotoxin-treated rats displayed lower ratios of RANKL and OPG mRNA expression than those recovered from the control group. The ratio of RANKL and osteoprotegerin protein expression and induction of RANKL-dependent osteoclastogenesis by the activated T-cells were also markedly decreased after kaliotoxin treatments in vitro. Conclusion: The use of kaliotoxin or other means to block Kv1.3 may constitute a potential intervention therapy to prevent alveolar bone loss in periodontal disease. [source]

    Confocal imaging of chromatographic fouling under flow conditions

    Sun Chau Siu
    Abstract BACKGROUND: The fouling impact of selected fouling species was assessed by utilising confocal scanning laser microscopy (CSLM) to image a packed chromatographic bed during operation. A custom-made flow cell was packed with Q Sepharose FF and loaded with partially clarified E. coli homogenate. Selective, multicoloured fluorescent dyes were used to label a bovine serum albumin (BSA) test protein (Cy5.5), dsDNA (PicoGreen) and host cell proteins (HCPs) (Cy3). The fouling caused by the various fluorescently labelled components was visualised as a result of the fluorescence emitted by the PicoGreen-labelled dsDNA and the Cy3-labelled protein in the foulant stream, and by testing the adsorptive capacity of a test protein (BSA) onto the resin prior to and post-fouling as well as following the application of a common CIP procedure. RESULTS: Values for the effective diffusivity of BSA (De) were derived from the confocal images and the fouling impact was assessed by comparing De values obtained from different fouling scenarios. Under the most extreme conditions examined, fouling caused a 20% reduction in capacity compared to a fresh bed. BSA diffusivity did not appear to be affected by the fouling conditions studied. Sequential CIP using 15 CVs of 1 mol L,1 NaCl then 15 CVs of 1 mol L,1 NaOH was shown to be effective in removing nucleic acids and HCPs. Subsequent BSA adsorption showed that the CIP regime successfully restored the column capacity to its original value. In contrast, 15 CVs of 1 mol L,1 NaCl were ineffective in removing dsDNA but substantially removed HCPs. CONCLUSION: CSLM was demonstrated to be a useful tool for visualising fouling mechanisms. Comparing the results obtained by this technique using different modes of chromatographic operation provided insights into the fouling characteristics of finite baths versus packed beds. Copyright © 2007 Society of Chemical Industry [source]

    Mass spectrometry of steroid glucuronide conjugates.

    -diol 3-, -steroid-, -steroid-17- O -, 17-glucuronides, 3-keto-, Electron impact fragmentation of 3-keto-4-en-, glucuronides
    Abstract The steroid glucuronide conjugates of 16,16,17-d3 -testosterone, epitestosterone, nandrolone (19-nortestosterone), 16,16,17-d3 -nortestosterone, methyltestosterone, metenolone, mesterolone, 5,-androstane-3,,17,-diol, 2,2,3,4,4-d5 -5,-androstane-3,,17,-diol, 19-nor-5,-androstane-3,,17,-diol, 2,2,4,4-d4 -19-nor-5,-androstane-3,,17,-diol and 1,-methyl-5,-androstane-3,/,,17,-diol were synthesized by means of the Koenigs,Knorr reaction. Selective 3- or 17- O -conjugation of bis-hydroxylated steroids was performed either by glucuronidation of the corresponding steroid ketole and subsequent reduction of the keto group or via a four-step synthesis starting from a mono-hydroxylated steroid including (a) protection of the hydroxy group, (b) reduction of the keto group, (c) conjugation reaction and (d) removal of protecting groups. The mass spectra and fragmentation patterns of all glucuronide conjugates were compared with those of the commercially available testosterone glucuronide and their characterization was performed by gas chromatography/mass spectrometry and nuclear magnetic resonance spectroscopy. For mass spectrometry the substances were derivatized to methyl esters followed by trimethylsilylation of hydroxy groups and to pertrimethylsilylated products using labelled and unlabelled trimethylsilylating agents. The resulting electron ionization mass spectra obtained by GC/MS quadrupole and ion trap instruments, full scan and selected reaction monitoring experiments are discussed, common and individual fragment ions are described and their origins are proposed. Copyright © 2001 John Wiley & Sons, Ltd. [source]

    Selective ,1 -adrenoreceptor blocking activity of newly synthesized acyl amino-substituted aryloxypropanolamine derivatives, DPJ 955 and DPJ 890, in rats

    K. Nandakumar
    The in-vivo ,-adrenoreceptor antagonistic activity of test compounds DPJ 955 and DPJ 890 was assessed against ,-adrenoreceptor agonist (isoprenaline) induced tachycardia in anaesthetized rats. The selectivity to block isoprenaline responses on different ,-adrenoreceptor subtypes (,1, ,2 and ,3) of the test compounds was carried out on isolated rat right atria, isolated rat uterus and isolated rat colon preparations, respectively. Intravenous injection of isoprenaline alone in anaesthetized rats caused hypotension and tachycardia. DPJ 955 or DPJ 890 alone produced a fall in mean arterial pressure and bradycardia in a dose-dependent manner. Administration of isoprenaline to anaesthetized rats pre-treated with test compounds significantly blocked both the tachycardial and hypotensive responses induced by isoprenaline. The test compounds shifted the concentration response curves of isoprenaline towards the right for isolated rat right atrial preparations, rat uterus and rat colon, indicating ,1, ,2 and ,3 adrenoreceptor blockade, respectively. The selectivity ratio for ,1/,-adrenoreceptors to DPJ 955 and DPJ 890 was 64.6 and 83.2, respectively. DPJ 890 was more potent in blocking ,1 -adrenoreceptors and was more selective towards ,1 receptors than to other ,-adrenoreceptor subtypes. In conclusion, DPJ 955 and DPJ890 have ,-adrenoreceptor blocking activity with high selectivity for the ,1 -adrenoreceptor subtype. [source]

    Antagonistic effects of selective ,1 -adrenoceptor antagonists MDL73005EF and tamsulosin and partial agonists clonidine and tizanidine in rat thoracic aorta and rabbit iliac artery

    Mitsutoshi Satoh
    The antagonistic effects of MDL73005EF and tamsulosin and partial agonists clonidine and tizanidineat rat thoracic aorta and rabbit iliac artery ,1 -adrenoceptors were investigated in this study. Selective ,1 -adrenoceptor antagonists MDL73005EF and tamsulosin dose-dependently shifted the concentration-response curves for noradrenaline to the right. Schild plots of the results obtained from the inhibition by MDL73005EF (pA2 8.30 ± 0.04) and tamsulosin (pA2 10.51 ± 0.06) of noradrenaline yielded a straight line with a slope of unity in rat thoracic aorta. The slopes of Schild plots obtained from the inhibition by MDL73005EF and tamsulosin of noradrenaline were significantly different from unity in rabbit iliac artery. Schild plots of the results obtained from the inhibition by clonidine and tizanidine of noradrenaline yielded a straight line with a slope of unity in rat thoracic aorta (pA2 7.08 ± 0.04 and 7.32 ± 0.04, respectively). These results suggest that ,1D -adrenoceptors play a significant role in the ,1 -adrenoceptor-agonist-induced contraction of rat thoracic aorta and rabbit iliac artery, and that clonidine and tizanidine interact with the ,1D -adrenoceptor subtype as competitive antagonists in rat thoracic aorta. [source]

    Early, Selective, and Marked Loss of Sympathetic Nerves from the Islets of Biobreeder Diabetic Rats

    Q Mei
    To discover whether islet sympathetic nerves are damaged during the autoimmune destruction of islet B-cells, we immunostained sections of pancreas from Bio-Breeder (BB) diabetic rats, using antibodies against vesicular monoamine transporter 2 (VMAT2), a marker of sympathetic nerve terminals. We found a marked decrease in the VMAT2-positive fiber area in the islets of BB rats that had been diabetic for only 1,2 weeks compared with their nondiabetic controls. In contrast, there was no significant decrease in the VMAT2-positive fiber area in the exocrine pancreas in these early diabetic BB rats. Furthermore, streptozotocin-diabetic rats showed no decrease in VMAT2-positive fiber area in their islets compared with controls. The classical diabetic autonomic neuropathy (DAN) that eventually occurs in the heart was not present in BB diabetic rats at this early stage as evidenced by normal cardiac VMAT2 immunostaining and normal cardiac norepinephrine content. Also, in contrast to DAN, this islet neuropathy did not worsen with duration of diabetes. These data provide evidence of a heretofore unrecognized early sympathetic islet neuropathy (eSIN). Because eSIN occurs selectively in the islet, is rapid in onset, and is associated with autoimmune but not chemically induced diabetes, it is distinct from DAN in location, time course, and mechanism. [source]

    Possible therapeutic benefits of adenosine-potentiating drugs in reducing age-related degenerative disease in dogs and cats

    R. J. Scaramuzzi
    Adenosine is a ubiquitous, biologically important molecule that is a precursor of other biologically active molecules. It also is a component of some co-factors and has distinct physiological actions in its own right. Levels are maintained by synthesis from dietary precursors and re-cycling. The daily turnover of adenosine is very high. Adenosine can act either as a hormone by binding to adenosine receptors, four adenosine receptor subtypes have been identified, and as an intracellular modulator, after transport into the cell by membrane transporter proteins. One of the principal intracellular actions of adenosine is inhibition of the enzyme phosphodiesterase. Extracellular adenosine also has specific neuromodulatory actions on dopamine and glutamate. Selective and nonselective agonists and antagonists of adenosine are available. The tasks of developing, evaluating and exploiting the therapeutic potential of these compounds is still in its infancy. Adenosine has actions in the central nervous system (CNS), heart and vascular system, skeletal muscle and the immune system and the presence of receptors suggests potential actions in the gonads and other organs. Adenosine agonists improve tissue perfusion through actions on vascular smooth muscle and erythrocyte fluidity and they can be used to improve the quality of life in aged dogs. This article reviews the therapeutic potential of adenosine-potentiating drugs in the treatment of age-related conditions in companion animals, some of which may be exacerbated by castration or spaying at an early age. [source]

    Selective cyclooxygenase-2 inhibition suppresses basic fibroblast growth factor expression in human esophageal adenocarcinoma

    Mark Baguma-Nibasheka
    Abstract Inhibition of cyclooxygenase (COX)-2 is reported to suppress growth and induce apoptosis in human esophageal adenocarcinoma (EADC) cells, although the precise biologic mechanism is unclear. In this study we tested the hypothesis that the antitumor activity of COX-2 inhibitors may involve modulation of basic fibroblast growth factor (FGF-2), which is overexpressed in EADC. We evaluated the effects of NS-398, a selective COX-2 inhibitor, on FGF-2 expression and proliferation of EADC cell lines that express COX-2 and those that do not. We also correlated COX-2 and FGF-2 expression with clinico-pathologic findings and outcome in a well-characterized series of surgically resected EADC tissues. Seg-1 cells robustly expressed COX-2 and FGF-2, whereas Bic-1 cells expressed neither transcript. FGF-2 was reduced to undetectable levels in Seg-1 cells following NS-398 treatment, but increased within 4 h of drug removal. NS-398 significantly inhibited the growth of Seg-1 cells, and this effect was ameliorated by addition of exogenous FGF-2. In contrast, NS-398 had no effect on Bic-1 cell proliferation and FGF-2 alone had no effect on proliferation of either cell line. NS-398, or a neutralizing anti-FGF-2 antibody, induced apoptosis in Seg-1 cells, and these effects were inhibited by addition of exogenous FGF-2. COX-2 protein was strongly expressed in 46% (10/22) of EADCs, and was associated with a trend towards reduced disease-free survival. These findings indicate that the antitumor effects of COX-2 inhibition in EADC cells may be mediated via suppression of FGF-2, and that COX-2 may be a clinically relevant molecular marker in the management of human EADC. © 2007 Wiley-Liss, Inc. [source]

    Importance of Anterograde Visualization of the Coronary Venous Network by Selective Left Coronary Angiography Prior To Resynchronization

    Background: Understanding of coronary anatomy is essential to the advancement of cardiac resynchronization therapy (CRT) techniques. We determined whether the difficulties associated with catheterization of the coronary sinus (CS) and its lateral branches could be overcome by a preliminary angiographical study of the coronary venous system carried out during a pre-operative coronary angiography with examination of venous return. Methods and Results: All patients were scheduled for an exploratory angiography procedure and indicated for CRT. Group A patients were implanted with a CRT device after a right arterial angiographical procedure while group B patients had a selective left angiogram including examination of venous return. Data analyzed in group B were: position of CS ostium, number and distribution of lateral branches, and ability to preselect a marginal vein suitable for catheterization. Subsequent device implantation was guided by these parameters. A total of 96 and 89 patients were included in groups A and B, respectively. Implantation success rates were not different (98% and 100%, respectively), but CS catheterization time was reduced in group B (6 minutes vs 4 minutes; P < 10,6) as well as total time required to position the left ventricular lead (25 minutes vs 15 minutes; P < 10,6), fluoroscopy exposure (7 minutes vs 5 minutes; P < 10,6), and volume of contrast medium required (45 mL vs 15 mL; P < 10,6). Conclusion: A coronary angiographical study, including examination of the coronary venous return prior to implantation of a CRT device, can simplify the device implant and allows patient-specific preselection of appropriate tools for the procedure. [source]

    Validation of Criteria for Selective His Bundle and Para-Hisian Permanent Pacing

    F. CANTÙ M.D.
    Background: His Bundle (HB) pacing is a valid alternative to right ventricular pacing for patients with preserved His-ventricle conduction who are candidates for permanent stimulation. Permanent pacing in the HB area enables Selective HB pacing (SHBP) or para-Hisian pacing (PHP) to be achieved. The aim of our study was to draw up a set of easy criteria to differentiate and validate the two kinds of stimulations according to the pacing output and the ECG/EKG signals. Methods and Results: From February to July 2005, 17 patients eligible for a pacemaker (PM) procedure underwent implantation with the Medtronic SelectSecure® lead (Medtronic, Minneapolis, MN, USA) screwed into the HB area.SHBP was defined when the intrinsic QRS was equal, in both duration and morphology, to the paced QRS, the His-Ventricular (H-V) interval was equal to Pace-Ventricular interval (Vp-V) and, at low output, only the HB was captured, while increasing the output resulted in both the HB and right ventricular (RV) being captured (widening of QRS at high output). Conversely, PHP was defined when the intrinsic QRS differed from the paced one, either in morphology or in duration and, at high output, both the RV and HB were captured (non-SHBP), while decreasing the output resulted in losing HB capture (widening of QRS at low output). According to these criteria, SHBP was achieved in 11 patients, while in the remaining 6, PHP was obtained. No adverse events were reported. Conclusions: The above criteria enabled SHBP and PHP to be validated easily and clearly. A longer follow-up will be needed in order to ascertain whether the clinical outcome of these two approaches differs. [source]

    Selective, Tailored, Biopsychosocial Pain Treatment: Our Past Is Our Future

    PAIN MEDICINE, Issue 6 2007
    Rollin M. Gallagher MD
    No abstract is available for this article. [source]

    Treatment of Perchlorate-Contaminated Groundwater Using Highly Selective, Regenerable Ion-Exchange Technology: A Pilot-Scale Demonstration

    REMEDIATION, Issue 2 2002
    Baohua Gu
    Treatment of perchlorate-contaminated groundwater using highly selective, regenerable ion-exchange technology has been recently demonstrated at Edwards Air Force Base, California. At an influent concentration of about 450 ,g/l ClO4,, the bifunctional anion-exchange resin bed treated approximately 40,000 empty bed volumes of groundwater before a significant breakthrough of ClO4, occurred. The presence of relatively high concentrations of chloride and sulfate in site groundwater did not appear to affect the ability of the bifunctional resin to remove ClO4,. The spent resin bed was successfully regenerated using the FeCl3,HCl regeneration technique recently developed at the Oak Ridge National Laboratory, and nearly 100 percent of sorbed ClO4, was displaced or recovered after elution with as little as about two bed volumes of the regenerant solution. In addition, a new methodology was developed to completely destroy ClO4, in the FeCl3,HCl solution so that the disposal of perchlorate-containing hazardous wastes could be eliminated. It is therefore anticipated that these treatment and regeneration technologies may offer an efficient and cost-effective means to remove ClO4, from contaminated groundwater with significantly reduced generation of waste requiring disposal. © 2002 Wiley Periodicals, Inc. [source]

    Evidence that the human cutaneous venoarteriolar response is not mediated by adrenergic mechanisms

    C. G. Crandall
    The venoarteriolar response causes vasoconstriction to skin and muscle via local mechanisms secondary to venous congestion. The purpose of this project was to investigate whether this response occurs through ,-adrenergic mechanisms. In supine individuals, forearm skin blood flow was monitored via laser-Doppler flowmetry over sites following local administration of terazosin (,1 -antagonist), yohimbine (,2 -antagonist), phentolamine (non-selective ,-antagonist) and bretylium tosylate (inhibits neurotransmission of adrenergic nerves) via intradermal microdialysis or intradermal injection. In addition, skin blood flow was monitored over an area of forearm skin that was locally anaesthetized via application of EMLA (2.5 % lidocaine (lignocaine) and 2.5 % prilocaine) cream. Skin blood flow was also monitored over adjacent sites that received the vehicle for the specified drug. Each trial was performed on a minimum of seven subjects and on separate days. The venoarteriolar response was engaged by lowering the subject's arm from heart level such that the sites of skin blood flow measurement were 34 ± 1 cm below the heart. The arm remained in this position for 2 min. Selective and non-selective ,-adrenoceptor antagonism and presynaptic inhibition of adrenergic neurotransmission did not abolish the venoarteriolar response. However, local anaesthesia blocked the venoarteriolar response without altering ,-adrenergic mediated vasoconstriction. These data suggest that the venoarteriolar response does not occur through adrenergic mechanisms as previously reported. Rather, the venoarteriolar response may due to myogenic mechanisms associated with changes in vascular pressure or is mediated by a non-adrenergic, but neurally mediated, local mechanism. [source]

    Selective and Flexible Transformation of Biomass-Derived Platform Chemicals by a Multifunctional Catalytic System,

    ANGEWANDTE CHEMIE, Issue 32 2010
    Eine nachhaltige Versorgungskette: Die kontrollierte Überführung der aus Biomasse erhaltenen Plattformverbindungen Lävulinsäure (LA) und Itaconsäure (IA) in die entsprechenden Lactone, Diole oder cyclischen Ether (siehe Bild) wird durch einen multifunktionellen molekularen Katalysator möglich. [source]

    Selective Discharge of Electrostatic Charges on Electrets Using a Patterned Hydrogel Stamp,

    ANGEWANDTE CHEMIE, Issue 32 2010
    Xinlei Ma
    Malen mit Wasser: Ein topographisch gemusterter Stempel aus Agarosehydrogel wird genutzt, um Wasser , zum Zweck einer selektiven Entladung , auf einheitlich geladene PMMA-Elektrete zu drucken. Die hochaufgelösten elektrostatischen Ladungsmuster, die durch diesen einfachen Ansatz erzeugt werden, können die Reduktion von Metallionen induzieren und ermöglichen so die Herstellung von mikro- und nanoskaligen Metallstrukturen. PMMA=Polymethylmethacrylat. [source]