We have carried out an electrochemical and theoretical study on the relationship between electron transfer (ET) and hydrogen bonding in 11 different 9,10-anthraquinone (AQ) derivatives, including β-hydroxy AQs and their methoxylated analogs, in the presence of hydrogen donors in acetonitrile (ACN). The complementary effects of the intra- and intermolecular hydrogen bonds (HBs) on ET were studied by analyzing the complex formation constants derived from the intermolecular HB. Our results revealed that the inductive effect of the β substituent that indirectly controls the charge distribution on the AQ carbonyl oxygen, and steric hindrance at the β position, affect the complex formation constants.
View Article and Find Full Text PDFIn this study, we attempted to improve the non-aqueous titration method using N,N-dimethylformamide (DMF) in the Japanese Pharmacopoeia seventeenth edition (JP XVII) for advancement in experimental safety. As an alternative solvent for DMF, we demonstrate titrations using dimethyl sulfoxide (DMSO), which has similar properties as and much higher safety than DMF. Five drugs (i.
View Article and Find Full Text PDFThis study demonstrates the relation between the redox properties and cytotoxicity of anthraquinone derivatives with a hydroxyl and methoxy group. The redox behavior of the anthraquinone derivatives was initially observed via cyclic voltammetry and their characteristics were investigated using molecular orbital calculations. The cytotoxicity of the anthraquinone derivatives was then evaluated using human leukemia HL-60 and HO resistant HP100 cells, and its correlation with the redox properties of these compounds was investigated.
View Article and Find Full Text PDFThis study presents the initial 3-year results of the first in-human study of internal shunt restoration using completely autologous vascular grafts, "Biotubes," based on in-body tissue architecture. Biotubes (diameter, 6 mm; length, 7 cm) were prepared as autologous collagenous tubular tissues with approximately 0.5 mm wall thickness by embedding molds (two per patient), assembled with a silicone rod and a stainless steel pipe with many slits, into the patients' abdominal subcutaneous tissue for 2 months.
View Article and Find Full Text PDFJ Biomed Mater Res B Appl Biomater
October 2016
Completely autologous in vivo tissue-engineered connective tissue tubes (Biotubes) have promise as arterial vascular grafts in animal implantation studies. In this clinical study of patients undergoing peritoneal dialysis (PD) (n = 11; age: 39-83 years), we evaluated human Biotubes' (h-Biotubes) mechanical properties to determine whether Biotubes with feasibility as vascular grafts could be formed in human bodies. We extracted PD catheters, embedded for 4-47 months, and obtained tubular connective tissues as h-Biotubes (internal diameter: 5 mm) from around the catheter' silicone tubular parts.
View Article and Find Full Text PDFChem Pharm Bull (Tokyo)
August 2014
This study demonstrated that the electro-chemical analysis of hydrophobic quinones can be performed in liposome suspension systems. We prepared and analyzed liposome suspensions containing lapachol, which is a quinone-based anti-tumor activity compound. In this suspension system, a simple one redox couple of lapachol is observed.
View Article and Find Full Text PDFThe canonical Wnt/β-catenin signaling pathway plays a crucial role in the maintenance of the balance between proliferation and differentiation throughout embryogenesis and tissue homeostasis. β-Catenin, encoded by the Ctnnb1 gene, mediates an intracellular signaling cascade activated by Wnt. It also plays an important role in the maintenance of various types of stem cells including adult stem cells and cancer stem cells.
View Article and Find Full Text PDFA standard treatment has not yet been established for elderly small-cell lung cancer patients, especially when they have end-stage renal disease. We report the first case of successful chemoradiotherapy in an elderly small-cell lung cancer patient undergoing continuous ambulatory peritoneal dialysis. A 77-year-old Japanese man on continuous ambulatory peritoneal dialysis was diagnosed as having limited disease small-cell lung cancer.
View Article and Find Full Text PDFThe diverse electrochemical and chemical oxidations of dichalcogena-mesocycles are analyzed, broadening our understanding of the chemistry of the corresponding radical cations and dications. 1,5-Diselenocane and 1,5-ditellurocane undergo reversible two-electron oxidation with inverted potentials analogous to 1,5-dithiocane. On the other hand, 1,5-selenathiocane and 1,5-tellurathiocane undergo one-electron oxidative dimerization.
View Article and Find Full Text PDF3,4-Methylenedioxymethamphetamine (MDMA, ecstasy) is a synthetic recreational drug of abuse that produces long-term toxicity associated with the degeneration of serotonergic nerve terminals. In various animal models, direct administration of MDMA into the brain fails to reproduce the serotonergic neurotoxicity, implying a requirement for the systemic metabolism and bioactivation of MDMA. Catechol-thioether metabolites of MDMA, formed via oxidation of 3,4-dihydroxymethamphetamine and 3,4-dihydroxyamphetamine (HHMA and HHA) and subsequent conjugation with glutathione (GSH), are selective serotonergic neurotoxicants when administered directly into brain.
View Article and Find Full Text PDFThe reactions of the previously reported cluster complexes [Re(6)(mu(3)-Se)(8)(PEt(3))(5)I]I, trans-[Re(6)(mu(3)-Se)(8)(PEt(3))(4)I(2)], and cis-[Re(6)(mu(3)-Se)(8)(PEt(3))(4)I(2)] with the [Re(6)(mu(3)-Se)(8)](2+) core with CO in the presence of AgSbF(6) afforded the corresponding cluster carbonyls [Re(6)(mu(3)-Se)(8)(PEt(3))(5)(CO)][SbF(6)](2) (), trans-[Re(6)(mu(3)-Se)(8)(PEt(3))(4)(CO)(2)][SbF(6)](2) (), and cis-[Re(6)(mu(3)-Se)(8)(PEt(3))(4)(CO)(2)][SbF(6)](2) (). Infrared spectroscopy indicated weakening of the bond in CO, suggesting the existence of backbonding between the cluster core and the CO ligand(s). Electrochemical studies focusing on the reversible, one-electron oxidation of the cluster core revealed a large increase in the oxidation potential upon going from the acetonitrile derivatives to their carbonyl analogs, consistent with the depleted electron density of the cluster core upon CO ligation.
View Article and Find Full Text PDFNihon Ronen Igakkai Zasshi
September 2007
Extended investigation of electrocatalytic generation of dihydrogen using [(mu-1,2-benzenedithiolato)][Fe(CO)3]2 has revealed that weak acids, such as acetic acid, can be used. The catalytic reduction producing dihydrogen occurs at approximately -2 V for several carboxylic acids and phenols resulting in overpotentials of only -0.44 to -0.
View Article and Find Full Text PDFThe electrochemical reduction of 3,5-di-tert-butyl-1,2-benzoquinone, 1, has been studied in acetonitrile with added 2,2,2-trifluoroethanol, 2. At low concentrations of 2 the reaction proceeds by the following pathway: reduction of the quinone (Q) to its anion radical (Q*-) followed by complexation of the anion radical with 2 (HA) and the further reduction of the hydrogen-bonded complex (Q*- (HA)) to form HQ- and A-. The latter reaction is a concerted proton and electron- transfer reaction (CPET).
View Article and Find Full Text PDFThe effect of genistein, a soybean isoflavone, on new bone formation by bone marrow cells from mature rats and humans was examined. Bone marrow cells were collected from the femoral diaphysis of 7-week-old Fisher rats, cultured in MEM containing fetal calf serum and then cultured with or without the addition of dexamethasone to the bone-forming medium. Genistein was added at concentrations of 10(-5),10(-6),10(-7) or 10(-8) M.
View Article and Find Full Text PDFThe tosylation reaction of endocrine-disruptive alkylphenolic compounds in a solid-phase aqueous system was investigated with the aim of developing an environment-friendly and efficient derivatization method for HPLC analyses of environmental samples. The phenols were rapidly and efficiently converted to the tosyl derivatives on a commercially available ODS solid-phase cartridge by passing an aqueous buffer solution through it. The solid-phase aqueous tosylation system has been incorporated into a preconcentration step performed by solid-phase extraction from environmental water.
View Article and Find Full Text PDFObjective: To report a case of a 47 XYY male neonate with congenital heart disease and short stature.
Description: This is the first case report of a 47 XYY male neonate associated with congenital heart disease (total anomalous pulmonary venous return) and small for date. The boy neonate was born at around 32 weeks of gestation with birthweight of 1134 g.
We have investigated analysis of anion radicals of phenanthrenequinone (PhQ) and anthraquinone (AQ) using acetonitrile-capillary electrophoresis (CE) under anaerobic conditions. PhQ and AQ have relatively high negative reduction potentials meaning that their anion radicals are re-oxidized quite readily by the surrounding O(2) to disappear during analysis and we failed to detect them with our previous system. In this work, we have developed an on-line system combining a unique electrolysis cell for generation of the radicals and a CE unit to keep the analysis system free from external O(2) molecules and to reduce analysis time remarkably.
View Article and Find Full Text PDFWe have investigated detection of the anion radical and the divalent anion of tetracyanoquinodimethane (TCNQ) by acetonitrile-CE under anaerobic conditions. With electrolysis at a potential of 0.0 V (vs.
View Article and Find Full Text PDFMicrobiology (Reading)
September 1997
The gene homologous to glutathione synthetase of Escherichia coli was inactivated in the cyanobacterium Synechococcus sp. PCC 7942. The region of genomic DNA including the mutation site was isolated from the mutant by plasmid rescue and the native gene of the wild-type was cloned from a genomic DNA library of the wild-type using the flanking DNA as a probe.
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