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Kim, Su N.,Seo, Ji Y.,Jung, Da W.,Lee, Min Y.,Jung, Young S.,Kim, Young C. American Society for PharmacologyExperimental Ther 2007 Drug metabolism and disposition: the biological fa Vol.35 No.10
<P>Dichloromethane (DCM) is metabolically converted to carbon monoxide mostly by CYP2E1 in liver, resulting in elevation of blood carboxyhemoglobin (COHb) levels. We investigated the effects of a subtoxic dose of acetaminophen (APAP) on the metabolic elimination of DCM and COHb elevation in adult female rats. APAP, at 500 mg/kg i.p., was not hepatotoxic as measured by a lack of change in serum aspartate aminotransferase, alanine aminotransferase, and sorbitol dehydrogenase activities. In rats pretreated with APAP at this dose, the COHb elevation resulting from administration of DCM (3 mmol/kg i.p.) was enhanced significantly. Also blood DCM levels were reduced, and its disappearance from blood appeared to be increased. Hepatic CYP2E1-mediated activities measured with chlorzoxazone, p-nitrophenol, and p-nitroanisole as substrates were all induced markedly in microsomes of rats treated with APAP. Aminopyrine N-demethylase activity was also increased slightly, but significantly. Western blot analysis showed that APAP treatment induced the expression of CYP2E1 and CYP3A proteins. Neither hepatic glutathione contents nor glutathione S-transferase activity was changed by the dose of APAP used. The results indicate that, contrary to the well known hepatotoxic effects of this drug at large doses, a subtoxic dose of APAP may induce CYP2E1, and to a lesser degree, CYP3A expression. This is the first report that APAP can increase cytochrome P450 (P450)-mediated hepatic metabolism and the resulting toxicity of a xenobiotic in the whole animal. The pharmacological/toxicological significance of induction of P450s by a subtoxic dose of APAP is discussed.</P>
Edwin David Morales-Álvarez,Claudia Marcela Rivera-Hoyos,Angélica María Baena-Moncada,Patricia Landázuri,Raúl A. Poutou-Piñales,Homero Sáenz-Suárez,Luis A. Barrera,Olga Y. Echeverri-Peña 한국미생물학회 2013 The journal of microbiology Vol.51 No.2
The sulfatase family involves a group of enzymes with a large degree of similarity. Until now, sixteen human sulfatases have been identified, most of them found in lysosomes. Human deficiency of sulfatases generates various genetic disorders characterized by abnormal accumulation of sulfated intermediate compounds. Mucopolysaccharidosis type II is characterized by the deficiency of iduronate 2-sulfate sulfatase (IDS), causing the lysosomal accumulation of heparan and dermatan sulfates. Currently, there are several cases of genetic diseases treated with enzyme replacement therapy, which have generated a great interest in the development of systems for recombinant protein expression. In this work we expressed the human recombinant IDS-Like enzyme (hrIDS-Like) in Escherichia coli DH5α. The enzyme concentration revealed by ELISA varied from 78.13 to 94.35 ng/ml and the specific activity varied from 34.20 to 25.97 nmol/h/mg. Western blotting done after affinity chromatography purification showed a single band of approximately 40 kDa, which was recognized by an IgY polyclonal antibody that was developed against the specific peptide of the native protein. Our 100 ml-shake-flask assays allowed us to improve the enzyme activity seven fold,compared to the E. coli JM109/pUC13-hrIDS-Like system. Additionally, the results obtained in the present study were equal to those obtained with the Pichia pastoris GS1115/pPIC-9-hrIDS-Like system (3 L bioreactor scale). The system used in this work (E. coli DH5α/pGEX-3X-hrIDS-Like)emerges as a strategy for improving protein expression and purification, aimed at recombinant protein chemical characterization,future laboratory assays for enzyme replacement therapy, and as new evidence of active putative sulfatase production in E. coli.
Effect of Austempering Treatment on Microstructure and Mechanical Properties of M50NiL Bearing Steel
Y. B. Li,W. Ren,X. F. Yu,Y. Su,S. J. Wang,Y. Liu,S. Yang,W. J. Liu 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.11
By means of microstructure observation, microhardness, tensile and rotating bending fatigue tests, the effects of austemperingtreatment on the formation of lower bainite, carbide precipitation and mechanical properties of M50NiL bearing steel werestudied. Results showed that multi-layer composite microstructure was formed in the steel after austempering treatment. Themicrostructure of the surface layer was mainly consisted of lower bainite, martensite and carbides, that of the sub-surfacelayer contained granular carbides, a little lower bainite, lath martensite, twin martensite and thin film retained austenite, andthat of the core region mostly contained lath martensite. In contrast with the traditional martensite quenching treatment,there was more lower bainite formed in the surface layer after austempering treatment. The appearance of acicular bainitedramatically decreased the effective grain size by refining the microstructure, and there were more finer carbides precipitatedin the lath martensite. After austempering treatment and tempering, the average hardness in surface layer of the steel increasedfrom 746.5 HV0.5to 786.4 HV0.5,and the rotating bending fatigue limit of the steel increased from 870.9 to 1170.0 MPa, butthe tensile strength of the steel decreased slightly. The effects of austempering treatment on the mechanical properties hada close relationship with the carbide precipitation behavior and the formation of lower bainite.
Mechanics of stretchable electronics on balloon catheter under extreme deformation
Su, Y.,Liu, Z.,Wang, S.,Ghaffari, R.,Kim, D.H.,Hwang, K.C.,Rogers, J.A.,Huang, Y. Pergamon Press ; Elsevier Science Ltd 2014 International journal of solids and structures Vol.51 No.7
Stretchable electronics has been applied to balloon catheters for high-efficacy ablation, with tactile sensing integrated on the surface, to establish full and conformal contact with the endocardial surface for elimination of the heart sink caused by blood flow around their surfaces. The balloon of the catheter folds into uniform 'clover' patterns driven by the pressure mismatch inside (~vacuum) and outside of the balloon (pressure ~1atm). The balloon catheter, on which microelectrodes and interconnects are printed, undergoes extreme mechanical deformation during its inflation and deflation. An analytic solution is obtained for balloon catheter inflation and deflation, which gives analytically the distribution of curvatures and the maximum strain in the microelectrodes and interconnects. The analytic solution is validated by the finite element analysis. It also accounts for the effect of inflated radius, and is very useful to the optimal design of balloon catheter.
Su, X H,Duan, R,Sun, Y Y,Wen, J F,Kang, D G,Lee, H S,Cho, K W,Jin, S N The Society 2014 Journal of physiology and pharmacology Vol.65 No.3
<P>Rubus chingii Hu (Rosaceae) is an important traditional Chinese medicine that has been used to improve function of the kidney and treat excessive polyuria. However, the effects of Rubus chingii on the cardiovascular system and its pharmacological mechanisms of action have not been studied. The aim of the present study was to evaluate the cardiovascular effects of ethanol extract of Rubus chingii (ERC) in rats. The changes in systolic blood pressure and heart rate of rats and vascular tone of aortic rings in in vitro were measured using pressure transducer and force transducer, respectively, connected to a multichannel recording system. ERC decreased systolic blood pressure and heart rate in a concentration-dependent manner. ERC induced vasorelaxation in a concentration-dependent manner. The ERC-induced vasorelaxation was not observed in the absence of the endothelium. The vasorelaxant effect of ERC was significantly attenuated by inhibition of endothelial NO synthase (eNOS), soluble guanylyl cyclase (sGC), or Ca(2+) entry from extracellular sources with L-NAME, ODQ, diltiazem, or extracellular Ca(2+) depletion, respectively. Similarly, an inhibition of Akt with wortmannin attenuated the ERC-induced vasorelaxation. Modulators of the store-operated Ca(2+) entry, thapsigargin, Gd(3+), and 2-aminoethyl diphenylborinate markedly attenuated the ERC-induced vasorelaxation. Furthermore, 4-aminopyridine an inhibitor of voltage-dependent K(+) (KV) channel, significantly attenuated the ERC-induced vasorelaxation. However, tetraethylammonium and glibenclamide, had no significant effect on the ERC-induced vasorelaxation. Indomethacin, atropine, and propranolol had no effects on the ERC-induced vasorelaxation. The present study demonstrates that ERC induces vasorelaxation via endothelium-dependent two-step signaling: an activation of the Ca(2+)-eNOS-NO signaling in the endothelial cells and then subsequent stimulation of the NO-sGC-cGMP-KV channel signaling in the vascular smooth muscle cells. The Akt-eNOS pathway is also suggested to be involved in this relaxation. Also, the findings suggest that the ERC-induced vasorelaxation is closely related to the hypotensive action of the agent.</P>