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Biomedical subjects

Hiroyuki Imai

Publications and source records attributed to Hiroyuki Imai.

6 recordsLinked to original sources
PubMed2026

Tail-degloving and cold storage facilitate primary cell culture from wild-caught rodents.

The use of wild rodents as biological resources is hindered by the difficulties of live transport and primary culture contamination caused by skin bacteria. To address this, we developed a "tail-degloving" method to physically remove the contaminated external integument. Using the large Japanese field mouse (Apodemus speciosus), this method suppressed contamination compared to conventional biopsies, yielding cells within 5-7 days that were capable of subculturing and cryopreservation. The protocol withstood 4°C storage for up to 7 days and enabled contamination-free cell establishment from a large rodent. This tail-degloving protocol eliminates live transport risks and effectively establishes primary cells after a multi-day transport delay.

Aseptic sampling↗
PubMed2006

Formation of p-phenylenediamine-crown ether-[PMo12O40]4- salts.

Electron transfer from the electron donor of p-phenylenediamine (PPD) to the electron acceptor of (H+)3[PMo12O40]3- forms a one-electron-reduced Keggin cluster of [PMo12O40]4-, bearing a S = 1/2 spin, while proton transfer from the proton donor of (H+)3[PMo12O40]3- to the proton acceptor of PPD yielded mono- and diprotonated cations of 4-aminoanilinium (HPPD+) and p-phenylenediammonium (H2PPD2+). By introduction of crown ether receptors during the crystallization process, supramolecular cations of (HPPD+)(crown ethers) and/or (H2PPD2+)(crown ethers) were successfully introduced into three new alpha-[PMo12O40]4- salts of (H2PPD2+)2([12]crown-4)4[PMo12O40]4- (1), (HPPD+)4([15]crown-5)4[PMo12O40]4- (2), and (HPPD+)2(H2PPD2+)([18]crown-6)4[PMo12O40]4- (3) as the countercation. The protonated states of PPD and molecular-assembly structures of the supramolecular cations depended on the size of the crown ethers. In salt 3, a novel mixed-protonated state of HPPD+ and H2PPD2+ was confirmed to be complexed in the cation structure. According to the changes in the cation structures, the anion arrangements were modulated from those of the two-dimensional layer for salt 1 to the isolated cluster for salts 2 and 3. The temperature-dependent magnetic susceptibilities of salts 1-3 were consistent with the isolated spin arrangements of [PMo12O40]4-. The electronic spectra of salts 1-3 indicated the intervalence optical transition from pentavalent Mo(V) to hexavalent Mo(VI) ions within the [PMo12O40]4- cluster. Temperature-dependent electron spin resonance spectra of salt 2 revealed the delocalization-localization transition of the S = 1/2 spin at 60 K. The spin on the [PMo12O40]4- cluster was localized on a specific Mo(V) site below 60 K, which was thermally activated with an activation energy of 0.015 eV.

Journal Article↗
PubMed2006

Synthesis, isolation, and structural characterization of the C4h isomer of metal(1,2-naphthalocyanine) and its one-dimensional conductor of the axially substituted species.

The C4h isomer of the 1,2-Nc (1,2-naphthalocyaninato) ligand has been efficiently isolated as a hydrated magnesium complex by the fractional crystallization from the benzene/acetone solution after treating the crude mixture of the four isomers (C4h, C(s), C2v, D2h) with benzene. The C4h symmetry has been confirmed by X-ray structure analysis. The central metal ion has been demetalated and subsequently converted to the Li2 complex followed by conversion to the cobalt(II) complex. Electrochemical oxidation of the Co(III)(1,2-Nc)(CN)2 anion prepared from the cobalt(II) complex with TPP (tetraphenylphosphonium) has yielded a partially oxidized salt, TPP[Co(III)(1,2-Nc-C4h(CN)2]2. The crystal comprises slipped stacked Co(III)(1,2-Nc-C4h)(CN)2 one-dimensional chains and one-dimensional arrays of TPPs. The conductivity at room temperature is 0.1 S cm(-1), and the temperature dependence is semiconducting with a small activation energy of about 0.05 eV. The positive temperature-independent value of about 60 microV deg(-1) observed in the thermoelectric power measurements suggests that the salt is in the correlated hopping regime.

Journal Article↗
PubMed2005

Phosphorylation of sphingoid long-chain bases in Arabidopsis: functional characterization and expression of the first sphingoid long-chain base Kinase gene in plants.

Sphingoid long-chain base (LCB) kinase catalyzes the phosphorylation of LCBs to form LCB 1-phosphates. Based on sequence identity to murine sphingosine kinase (mSPHK1), we cloned and characterized the first plant LCB kinase gene from Arabidopsis (AtLCBK1). Using recombinant AtLCBK1 protein from Escherichia coli cells, we confirmed that the enzyme specifically phosphorylated D-erythro-dihydrosphingosine (DHS), but not N-acetyl-DHS or D-threo-DHS. AtLCBK1 also phosphorylated D-erythro-sphingosine, trans-4, trans-8-sphingadienine and phytosphingosine. We found that AtLCBK1 mRNA is highly expressed in flowers. AtLCBK1 transcripts were slightly increased by low humidity or abscisic acid treatments, suggesting that AtLCBK1 is constitutively expressed under these treatments.

Amino Acid Sequence↗
PubMed2002

Rupture of a bleeding pancreatic pseudocyst into the stomach.

A bleeding pancreatic pseudocyst following pancreatitis is a severe complication that can lead to massive gastrointestinal bleeding. Rupture of such a pseudocyst into the stomach is rare. We report herein a case of rupture of a bleeding pseudocyst into the stomach in a patient who was successfully treated with emergency surgery. A 60-year-old Japanese man with a history of chronic alcoholic pancreatitis with a pancreatic tail pseudocyst was referred to us because of hematemesis. The cavity of the pseudocyst, which was 3 cm in size and whose wall adhered to the stomach, was enhanced by dynamic bolus computed tomography (CT) in the late arterial phase. Splenic angiography revealed a bleeding pseudocyst in the splenic hilum. Embolization of the pseudocyst failed, because of arterial spasm. A distal pancreatectomy, splenectomy, and total gastrectomy were performed. The wall of the pseudocyst consisted of the pancreatic tail, granulation tissue, and the posterior wall of the stomach. The patient's postoperative course was uneventful. In the management of massive bleeding from a pseudocyst, early diagnosis with dynamic bolus CT and angiography is essential. A bleeding pseudocyst should be considered to be a lethal complication, but it can possibly be treated with a combination of angiographic embolization and surgery.

Angiography↗