Kida T

References (4)

Title : Synthesis, Properties, and Biodegradability of Thermoplastic Elastomers Made from 2-Methyl-1,3-propanediol, Glutaric Acid and Lactide - Zahir_2021_Life.(Basel)_11_
Author(s) : Zahir L , Kida T , Tanaka R , Nakayama Y , Shiono T , Kawasaki N , Yamano N , Nakayama A
Ref : Life (Basel) , 11 : , 2021
Abstract : An innovative type of biodegradable thermoplastic elastomers with improved mechanical properties from very common and potentially renewable sources, poly(L-lactide)-b-poly(2-methyl-1,3-propylene glutarate)-b-poly(L-lactide) (PLA-b-PMPG-b-PLA)s, has been developed for the first time. PLA-b-PMPG-b-PLAs were synthesized by polycondensation of 2-methyl-1,3-propanediol and glutaric acid and successive ring-opening polymerization of L-lactide, where PMPG is an amorphous central block with low glass transition temperature and PLA is hard semicrystalline terminal blocks. The copolymers showed glass transition temperature at lower than -40 degreesC and melting temperature at 130-152 degreesC. The tensile tests of these copolymers were also performed to evaluate their mechanical properties. The degradation of the copolymers and PMPG by enzymes proteinase K and lipase PS were investigated. Microbial biodegradation in seawater was also performed at 27 degreesC. The triblock copolymers and PMPG homopolymer were found to show 9-15% biodegradation within 28 days, representing their relatively high biodegradability in seawater. The macromolecular structure of the triblock copolymers of PLA and PMPG can be controlled to tune their mechanical and biodegradation properties, demonstrating their potential use in various applications.
ESTHER : Zahir_2021_Life.(Basel)_11_
PubMedSearch : Zahir_2021_Life.(Basel)_11_
PubMedID: 33445658

Title : N-[18F]fluoroethyl-4-piperidyl acetate ([18F]FEtP4A): A PET tracer for imaging brain acetylcholinesterase in vivo - Zhang_2003_Bioorg.Med.Chem_11_2519
Author(s) : Zhang MR , Furutsuka K , Maeda J , Kikuchi T , Kida T , Okauchi T , Irie T , Suzuki K
Ref : Bioorganic & Medicinal Chemistry , 11 :2519 , 2003
Abstract : N-[(18)F]Fluoroethyl-4-piperidyl acetate ([(18)F]FEtP4A) was synthesized and evaluated as a PET tracer for imaging brain acetylcholinesterase (AchE) in vivo. [(18)F]FEtP4A was previously prepared by reacting 4-piperidyl acetate (P4A) with 2-[(18)F]fluoroethyl bromide ([(18)F]FEtBr) at 130 degrees C for 30 min in 37% radiochemical yield using an automated synthetic system. In this work, [(18)F]FEtP4A was synthesized by reacting P4A with 2-[(18)F]fluoroethyl iodide ([(18)F]FEtI) or 2-[(18)F]fluoroethyl triflate ([(18)F]FEtOTf in improved radiochemical yields, compared with [(18)F]FEtBr under the corresponding condition. Ex vivo autoradiogram of rat brain and PET summation image of monkey brain after iv injection of [(18)F]FEtP4A displayed a high radioactivity in the striatum, a region with the highest AchE activity in the brain. Moreover, the distribution pattern of (18)F radioactivity was consistent with that of AchE in the brain: striatum>frontal cortex>cerebellum. In the rat and monkey plasma, two radioactive metabolites were detected. However, their presence might not preclude the imaging studies for AchE in the brain, because they were too hydrophilic to pass the blood-brain barrier and to enter the brain. In the rat brain, only [(18)F]fluoroethyl-4-piperidinol ([(18)F]FEtP4OH) was detected at 30 min postinjection. The hydrolytic [(18)F]FEtP4OH displayed a slow washout and a long retention in the monkey brain until the PET experiment (120 min). Although [(18)F]FEtP4A is a potential PET tracer for imaging AchE in vivo, its lower hydrolytic rate and lower specificity for AchE than those of [(11)C]MP4A may limit its usefulness for the quantitative measurement for AchE in the primate brain.
ESTHER : Zhang_2003_Bioorg.Med.Chem_11_2519
PubMedSearch : Zhang_2003_Bioorg.Med.Chem_11_2519
PubMedID: 12757720

Title : Synthesis and preliminary evaluation of [18F]FEtP4A, a promising PET tracer for mapping acetylcholinesterase in vivo - Zhang_2002_Nucl.Med.Biol_29_463
Author(s) : Zhang MR , Tsuchiyama A , Haradahira T , Furutsuka K , Yoshida Y , Kida T , Noguchi J , Irie T , Suzuki K
Ref : Nucl Med Biol , 29 :463 , 2002
Abstract : N-[18F]Fluoroethyl-4-piperidyl acetate ([18F]FEtP4A), an analog of [11C]MP4A for mapping brain acetylcholineseterase (AchE) activity, was prepared by reacting 4-piperidyl acetate (P4A) with [18F]fluoroethyl bromide ([18F]FEtBr) using a newly developed automated system. Preliminary evaluation showed that the initial uptake of [18F]FEtP4A in the mouse brain was > 8% injected dose/g tissue. The distribution pattern of [18F]FEtP4A in the brain was striatum>cerebral cortex>cerebellum within 10-120 min post-injection, which reflected the distribution rank pattern of AchE activity in the brain. Moreover, chemical analysis of in vivo radioactive metabolites in the mouse brain indicated that 83% of [18F]FEtP4A was hydrolyzed to N-[18F]fluoroethyl-4-piperidinol ([18F]FEtP4OH) after 1 min intravenous injection. From these results, [18F]FEtP4A may become a promising PET tracer for mapping the AchE in vivo.
ESTHER : Zhang_2002_Nucl.Med.Biol_29_463
PubMedSearch : Zhang_2002_Nucl.Med.Biol_29_463
PubMedID: 12031881

Title : Three point mutations of human butyrylcholinesterase in a Japanese family and the alterations of three-dimensional structure - Asanuma_1999_Clin.Chim.Acta_283_33
Author(s) : Asanuma K , Yagihashi A , Uehara N , Kida T , Watanabe N
Ref : Clinica Chimica Acta , 283 :33 , 1999
Abstract : Three different mutations at codons 330 (TTA to ATA), 365 (GGA to AGA) and 515 (CGT to TGT) of human butyrylcholinesterase (hBChE) were identified in a Japanese family. We correlated alterations in in the patient's hBChE activity with possible structural alterations in the three-dimensional structure of hBChE caused by the point mutations. This study was performed using the published computer-generated three-dimensional structure of hBChE based on the structure of acetylcholinesterase. The amino acid substitution at L330I was adjacent to hydrophobic residues that form the channel domain of the active center. This side chain faced the side opposite the active center. The amino acid substitution at G365R was located at the position most remote from the active center, and this substitution site was exposed to the surface of the BChE protein. Alpha-helical structure was present to the active center, and the guanidyl residue of native Arg 515 was hydrogen-bonded to the carboxyl group of Asp 395 in the alpha-helix. These point mutations may cause steric effects on the present patient's hBChE activity. This is the first report of three-dimensional structural analysis performed on the L330I, G365R, and R515C mutations of hBChE.
ESTHER : Asanuma_1999_Clin.Chim.Acta_283_33
PubMedSearch : Asanuma_1999_Clin.Chim.Acta_283_33
PubMedID: 10404729