Publications by authors named "Masaki Yokota"

We encountered two patients with overlapping features of primary biliary cholangitis and autoimmune hepatitis within the same family. A 68-year-old woman presented at our hospital from a previous medical institution because of the diagnosis of primary biliary cholangitis. Her 49-year-old daughter was admitted with liver dysfunction 4 years later.

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Signal transducers and activators of transcription 6 (STAT6) is a key regulator of the type 2 helper T (Th2) cell immune response and a potential therapeutic target for allergic diseases such as asthma and atopic diseases. To search for potent and orally bioavailable STAT6 inhibitors, we synthesized a series of 4-benzylaminopyrimidine-5-carboxamide derivatives and evaluated their STAT6 inhibitory activities. Among these compounds, 2-[(4-morpholin-4-ylphenyl)amino]-4-[(2,3,6-trifluorobenzyl)amino]pyrimidine-5-carboxamide (25y, YM-341619, AS1617612) showed potent STAT6 inhibition with an IC(50) of 0.

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The STAT6 (signal transducers and activators of transcription 6) protein is activated by interleukin (IL)-4 and IL-13, and plays an important role in T-helper cell 2 (Th2) differentiation. STAT6 might therefore be an excellent therapeutic target for various allergic conditions, including asthma and atopic diseases. We synthesized a series of 2-{[2-(4-hydroxyphenyl)ethyl]amino}pyrimidine-5-carboxamide derivatives and evaluated their STAT6 inhibitory activities.

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To discover an orally active thromboxane A(2) (TXA(2)) and leukotriene D(4) (LTD(4)) dual antagonist, we designed and synthesized chloroquinolylvinyl derivatives based on the structures of the TXA(2) antagonist daltroban and the LTD(4) antagonist montelukast. Among these derivatives, 4-{[(2-(4-chlorophenylsulfonylamino)-1-{3-[(E)-2-(7-chloro-2-quinolyl)vinyl]phenyl}ethyl)thio]methyl}benzoic acid (18d) showed potent inhibitory activity against U46619-induced aggregation of guinea pig platelets and LTD(4)-induced contraction in the guinea pig ileum, with IC(50) values of 340 nm and 0.40 nm, respectively.

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A 17-year-old man was admitted to hospital because of epigastric pain. Various imaging studies showed a solid tumor (4cm in diameter) in the tail of the pancreas, multiple hypovascular tumors in liver. Serum levels of DUPAN2, SPAN1 and NSE were elevated slightly.

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A 62-year-old man with carcinomatous ascites more than 5 years after early gastric cancer operation was admitted to our hospital because of suspected pancreatic cancer, and was diagnosed with a relapse of the gastric cancer. TS-1 was administered at a dose of 120 mg/day. At the end of 1 course a partial response of a decrease of tumor markers and ascites and improvement of QOL was achieved, and the patient was followed in the outpatient clinic.

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A patient with advanced gastric cancer complicated with liver and lymph node metastases was successfully treated with a novel oral anticancer drug, TS-1, TS-1 was administered at a dose of 100 mg/day. One course consisted of consecutive administration of TS-1 for 28 days and withdrawal for 14 days. At the end of 3 courses a partial response of the liver metastases was achieved.

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