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안준성,Hye-Seon Kim,박종상 대한화학회 2013 Bulletin of the Korean Chemical Society Vol.34 No.5
The two major symptoms characterizing Alzheimer’s disease are the formation of amyloid-β extracellular deposits in the form of senile plaques and intracellular neurofibrillary tangles (NFTs) that consist of pathological hyperphosphorylated tau protein aggregated into insoluble paired helical filaments (PHFs). Neurons of the central nervous system have appreciable amounts of tau protein, a microtubule-associated protein. To maintain an optimal operation of nerves, the microtubules are stabilized, which is necessary to support cell structure and cellular processes. When the modified tau protein becomes dysfunctional, the cells containing misfolded tau cannot maintain cell structure. One of the pathological hallmarks of Alzheimer’s disease is hyperphosphorylated tau protein. This paper shows that the small heat shock protein from humans (Hsp27) reduces hyperphosphorylated tau and prevents hyperphosphorylated tau-induced cell death of the human neuroblastoma cell line SH-SY5Y.
안준성,전자룡,유홍석,박택규,박철근,신동현,백승운 대한간학회 2013 Clinical and Molecular Hepatology(대한간학회지) Vol.19 No.2
Hepatoid adenocarcinoma (HAC) is a rare type of extrahepatic carcinoma whose morphology is similar to that of hepatocellular carcinoma (HCC). Metachronous HCC and HAC in the same patient is extremely rare. The case of a 68-yearold man with chronic hepatitis B infection who had both HCC and HAC of the stomach is reported herein. Nine years previously this patient had been diagnosed with HCC and received a right lobectomy. HCC that recurred at the caudate lobe at 6 months after the operation was successfully treated with transarterial chemoembolization. The patient was followed up regularly thereafter without evidence of tumor recurrence for 9 years. In July 2010 his serum alphafetoprotein (AFP) level elevated from 6.5 ng/mL to 625.4 ng/mL, and he developed a probable single metastatic lymph node around the hepatic artery without intrahepatic lesions. Subsequent evaluation with upper endoscopy revealed a 4-cm ulcerative lesion on the antrum of the stomach. Subtotal gastrectomy was performed with lymph-node dissection. Histologic examination revealed a special type of extrahepatic AFP-producing adenocarcinoma-HAC with lymphnode metastasis-which indicates that HAC can be a cause of elevated AFP even in patients with HCC. HAC should be considered if a patient with stable HCC exhibits unusual elevation of AFP. (Clin Mol Hepatol 2013;19:173-178)
안준성,강지선,남궁길,엄익환 대한화학회 2011 Bulletin of the Korean Chemical Society Vol.32 No.7
Pseudo-first-order rate constants (k_(obsd)) have been measured spectrophotometrically for nucleophilic substitution reactions of 3,4-dinitrophenyl diphenylphosphinothioate 9 with alkali metal ethoxides (EtOM, M = Li, Na, K) in anhydrous ethanol at 25.0 ± 0.1 ^oC. The plot of k_(obsd) vs. [EtOM] is linear for the reaction of 9with EtOK. However, the plot curves downwardly for those with EtOLi and EtONa while it curves upwardly for the one with EtOK in the presence of 18-crown-6-ether (18C6). Dissection of k_(obsd) into k_(EtO)_ and k_(EtOM) (i.e.,the second-order rate constant for the reaction with dissociated EtO^– and ion-paired EtOM, respectively) has revealed that the reactivity increases in the order kEtOLi < k_(EtONa) < k_(EtO)_ ≈ k_(EtOK) < k_(EtOK/18C6), indicating that the reaction is inhibited by Li+ and Na+ ions but is catalyzed by 18C6-crowned K+ ion. The reactivity order found for the reactions of 9 contrasts to that reported previously for the corresponding reactions of 1, i.e., k_(EtOLi) > k_(EtONa)> k_(EtOK) > k_(EtO)_ ≈ k_(EtOK/18C6), indicating that the effect of changing the electrophilic center from P=O to P=S on the role of M^+ ions is significant. A four-membered cyclic transition-state has been proposed to account for the M+ ion effects found in this study, e.g., the polarizable sulfur atom of the P=S bond in 9 interacts strongly with the soft 18C6-crowned K^+ ion while it interacts weakly with the hard Li^+ and Na^+ ions.