31 research outputs found

    H-Ras oncogene counteracts the growth-inhibitory effect of genistein in T24 bladder carcinoma cells

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    Among eight human bladder cancer cell lines we examined, only T24 cells were resistant to the growth inhibition effect of genistein, an isoflavone and potent anticancer drug. Since the T24 cell line was the only cell line known to overexpress oncogenic H-Ras(val12), we investigated the role of H-Ras(val 12) in mediating drug resistance. Herein, we demonstrate that the phenotype of T24 cells could be dramatically reversed and became relatively susceptible to growth inhibition by genistein if the synthesis of H- Ras(val 12) or its downstream effector c-Fos had been suppressed. The inhibition of Ras-mediated signalling with protein kinase inhibitors, such as PD58059 and U0126 which inhibited MEK and ERK, in T24 cells also rendered the identical phenotypic reversion. However, this reversion was not observed when an inhibitor was used to suppress the protein phosphorylation function of PI3 K or PKC. These results suggest that the signal mediated by H-Ras(val 12) is predominantly responsible for the resistance of the cells to the anticancer drug genistein

    Measurement of the Bottom-Strange Meson Mixing Phase in the Full CDF Data Set

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    We report a measurement of the bottom-strange meson mixing phase \beta_s using the time evolution of B0_s -> J/\psi (->\mu+\mu-) \phi (-> K+ K-) decays in which the quark-flavor content of the bottom-strange meson is identified at production. This measurement uses the full data set of proton-antiproton collisions at sqrt(s)= 1.96 TeV collected by the Collider Detector experiment at the Fermilab Tevatron, corresponding to 9.6 fb-1 of integrated luminosity. We report confidence regions in the two-dimensional space of \beta_s and the B0_s decay-width difference \Delta\Gamma_s, and measure \beta_s in [-\pi/2, -1.51] U [-0.06, 0.30] U [1.26, \pi/2] at the 68% confidence level, in agreement with the standard model expectation. Assuming the standard model value of \beta_s, we also determine \Delta\Gamma_s = 0.068 +- 0.026 (stat) +- 0.009 (syst) ps-1 and the mean B0_s lifetime, \tau_s = 1.528 +- 0.019 (stat) +- 0.009 (syst) ps, which are consistent and competitive with determinations by other experiments.Comment: 8 pages, 2 figures, Phys. Rev. Lett 109, 171802 (2012

    Is Keeping Up with the Joneses Beneficial for Economic Growth?

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    [[abstract]]This paper builds a two-sector, environmental model in which agents optimally choose the clean- and dirty-goods in order to balance the concern for social status and environmental quality. In contrast to the conventional notion, we Önd that greater social aspirations in consumption regardless of either clean or dirty goods can lead to a deterioration in economic growth, provided that conspicuous goods are relatively labor-intensive. Besides, in the presence of conspicuous consumption, employment and growth may be negatively correlated, which provides theoretical support to the empirical evidence.[[notice]]補正完畢[[conferencetype]]國內[[conferencedate]]201212[[conferencelocation]]台北, 台

    Multiple inputs of GABA-immunoreactive neurons in the cuneate nucleus of the rat

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    10.1016/S0168-0102(96)01139-XNeuroscience Research272123-132NERA

    Immunohistochemical study of amoeboid microglial cells in fetal rat brain.

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    The present study examined the expression of different antigens in amoeboid microglial cells (AMC) in fetal rat brain extending from 12 to 20 d postconception (E12-E20) using a panel of monoclonal antibodies which recognised the major histocompatibility complex (MHC) class I (OX-18) and class II (OX-6) antigens, leucocyte common antigen (OX-1), CD4 receptor (OX-35), complement type 3 receptor (OX-42) or macrophage antigens of unknown function (ED1 and ED2). Of the above-mentioned antigens, ED1 and ED2-labelled AMC were observed in the neuroepithelia as early as embryonic day 12 (E12); other antigens were not detected at this stage. At E14, except for MHC class I antigen, all other antigens were expressed by AMC distributed predominantly in the developing white matter. At E16, AMC in the intermediate zone lateral to the striatum were endowed with all the above-mentioned antigens including MHC class I. At E18, the immunoreactivities of AMC stained with OX-6, OX-18, OX-35 and OX-42 antigens were noticeably reduced when compared with those cells at E16. At E20, amoeboid microglial cells exhibited full complement of antigen expression similar to those cells at E16; some of the labelled cells emitted a variable number of cytoplasmic processes. It is suggested that the successive and differential expression of various macrophage related antigens on AMC in fetal brain is related to the specific requirement of local environment in different stages of development

    Structure-reactivity relationships for the inhibition mechanism at the second alkyl-chain-binding site of cholesterol esterase and lipase

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    Alkyl-N-phenyl carbamates (2-8) (see Figure 1), alkyl-N-phenyl thiocarbamates (9-15), 2,2'-biphenyl-2-ol-2'-N-substituted carbamates (16-23), and 2, 2'-biphenyl-2-N-octadecylcarbamate-2'-N-substituted carbamates (24-31) are prepared and evaluated for their inhibition effects on porcine pancreatic cholesterol esterase and Pseudomona species lipase. All inhibitors are characterized as transient or pseudo substrate inhibitors for both enzymes. Both enzymes are not protected from inhibition and further inactivated by carbamates 2-8 and thiocarbamates 9-15 in the presence of trifluoroacetophenone. Therefore, carbamates 2-8 and thiocarbamates 9-15 are exceptions for active site binding inhibitors and are probably the second alkyl-chain binding-site-directed inhibitors for both enzymes. The inhibition data for carbamates 2-8 and thiocarbamates 9-15 are correlated with the steric constant, E-s, and the hydrophobicity constant, pi; however, the inhibition data are not correlated with the Taft substituent constant, sigma*. A comparison of the inhibition data for carbamates 2-8 and thiocarbamates 9-15 toward both enzymes indicates that thiocarbamates 9-15 are more potent inhibitors than carbamates 2-8. A comparison of the inhibition data for cholesterol esterase and Pseudomona species lipase by carbamates 2-8 or thiocarbamates 9-15 indicates that cholesterol esterase is more sensitive to the E-s and pi values than Pseudomona species lipase. The negative slope values for the logarithms of inhibition data for Pseudomona species lipase by carbamates 2-8 and thiocarbamates 9-15 versus E-s and pi indicate that the second alkyl-chain-binding site of Pseudomona species lipase is huge, hydrophilic, compared to that of cholesterol esterase, and prefers to interact with a bulky, hydrophilic inhibitor rather than a small, hydrophobic one. On the contrary, the second alkyl-chain-binding site of cholesterol esterase prefers to bind to a small, hydrophobic inhibitor. Both enzymes are protected from inhibition by carbamates 16-23 in the presence of trifluoroacetophenone. Therefore, carbamates 16-23 are characterized as the alkyl chain binding site, esteratic site oxyanion active site directed pseudo substrate inhibitors for both enzymes. Both enzyme inhibition data for carbamates 16-22 are well-correlated with sigma* alone. The negative rho* values for these correlations indicate that the serine residue of both enzymes and carbamates 16-22 forms the tetrahedral species with more positive charges than inhibitors and the enzymes and follow the formation of the carbamyl enzymes with more positive charges than the tetrahedral species. Carbamates 24-31 are also exceptions for active site binding inhibitors and probably the second alkyl chain binding site-directed inhibitors for both enzymes. However, the enzyme inhibition constants for carbamates 24-31 are correlated with values of sigma*, E-s, and pi. The negative rho* values for these correlations indicate that both enzymes and carbamates 24-31 form the tetrahedral species with more positive charges than inhibitors and the enzymes and follow the formation of the carbamyl enzymes with more positive charges than those tetrahedral species. Therefore, carbamates 24-31 may bind to both the active sites and the second alkyl chain binding site and follow the evacuation of the active sites. A comparison of the rho* values for cholesterol esterase and Pseudomona species lipase by carbamates 24-31 indicates that cholesterol esterase is much more sensitive to the sigma* values than Pseudomona species lipase. The negative sensitivity values, 9, for the cholesterol esterase inhibitions by carbamates 24-31 indicate that the enzyme prefers to bind to a bulky carbamyl group rather than bind to a small one. The hydrophobicity of carbamates 24-31 does not play a major role in both enzyme inhibitions
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