On sections of hyperelliptic Lefschetz fibrations

We construct a relation among right-handed Dehn twists in the mapping class group of a compact oriented surface of genus g with 4g+4 boundary components. This relation gives an explicit topological description of 4g+4 disjoint (-1)-sections of a hyperelliptic Lefschetz fibration of genus g on the manifold {CP}^2#(4g+5){-CP}^2.Comment: 19 pages, 21 figure

Electrochemically stable fluorohydrogenate ionic liquids based on quaternary phosphonium cations

Fluorohydrogenate ionic liquids of quaternary phosphonium cations, tri-n-butylmethylphosphonium (P4441) fluorohydrogenate, tetra-n-butylphosphonium (P4444) fluorohydrogenate, and tri-n-butyl-n-octylphosphonium (P4448) fluorohydrogenate, have been synthesized by the metatheses of anhydrous hydrogen fluoride and the corresponding phosphonium chloride precursors. All the obtained salts have melting points below room-temperature with a vacuum-stable composition of P₄₄₄ₘ(FH)₂.₃F (m = 1, 4, and 8) and were characterized by density, conductivity, and viscosity measurements. Linear sweep voltammetry with a glassy carbon working electrode shows that the P₄₄₄ₘ(FH)₂.₃Fs have wide electrochemical windows exceeding 5.2 V. In particular, P₄₄₄₁(FH)₂.₃F has an electrochemical window of 6.0 V, which is the widest among fluorohydrogenate ionic liquids reported to date. The thermal stability of these ionic liquids is also improved compared to the salts of N-heterocyclic ammonium cations

Stabilization of SF₅⁻ with Glyme-Coordinated Alkali Metal Cations

The stabilization of complex fluoroanions derived from weakly acidic parent fluorides is a significant and ongoing challenge. The [SF₅]⁻ anion is recognized as one such case, and only a limited number of [SF₅]⁻ salts are known to be stable at room temperature. In the present study, glyme-coordinated alkali metal cations (K⁺, Rb⁺, and Cs⁺) are employed to stabilize [SF₅]⁻, which provides a simple synthetic route to a [SF₅]⁻ salt. The reactivities of KF and RbF with SF₄ are significantly enhanced by complexation with G4, based on Raman spectroscopic analyses. A new room-temperature stable salt, [Cs(G4)₂][SF₅] (G4 = tetraglyme), was synthesized by stoichiometric reaction of CsF, G4, and SF₄. The vibrational frequencies of [SF₅]⁻ were assigned based on quantum chemical calculations, and the shift of the G4 breathing mode accompanying coordination to metal cations was confirmed by Raman spectroscopy. Single-crystal X-ray diffraction revealed that Cs⁺ is completely isolated from [SF₅]⁻ by two G4 ligands and [SF₅]⁻ is disordered along the crystallographic two-fold axis. Hirshfeld surface analysis reveals that the H···H interaction between two neighboring [Cs(G4)₂]⁺ moieties is more dominant on the Hirshfeld surface than the interaction between the H atom in glyme molecules and the F atom in [SF₅]⁻, providing a CsCl-type structural model where the large and spherical [Cs(G4)₂]⁺ cations contact each other and the [SF₅]⁻ anions occupy interstitial spaces in the crystal lattice. The [SF₅]⁻ anion, combined with [Cs(G4)₂]⁺, exhibits a very limited deoxofluorinating ability toward hydroxyl groups in both neat conditions and THF solutions

Flap Reconstruction for Esophageal Perforation Following Anterior Cervical Plate Fixation

Anterior cervical plate fixation is a common surgical treatment for cervical spine trauma, disc herniation, or cervical spondylosis. Esophageal perforation following anterior cervical plate fixation is a rare but serious complication. Management of esophageal perforation is controversial; however, we suggest treating most cases surgically because this condition is slow to heal and often fatal. We managed 2 cases of esophageal perforation following anterior cervical plate fixation by flap reconstruction with the pectoralis major muscle in one case and a jejunal free flap in the other. Here, we report our experience and review the surgical indications

Hepatocyte growth factor and Met in drug discovery

Activation of the hepatocyte growth factor (HGF)-Met pathway evokes dynamic biological responses that support the morphogenesis, regeneration and survival of cells and tissues. A characterization of conditional Met knockout mice indicates that the HGF-Met pathway plays important roles in the regeneration, protection and homeostasis of cells such as hepatocytes, renal tubular cells and neurons. Preclinical studies in disease models have indicated that recombinant HGF protein and expression plasmid for HGF are biological drug candidates for the treatment of patients with diseases or injuries that involve impaired tissue function. The phase-I and phase-I/II clinical trials of the intrathecal administration of HGF protein for the treatment of patients with amyotrophic lateral sclerosis and spinal cord injury, respectively, are ongoing. Biological actions of HGF that promote the dynamic movement, morphogenesis and survival of cells also closely participate in invasion-metastasis and resistance to the molecular-targeted drugs in tumour cells. Different types of HGF-Met pathway inhibitors are now in clinical trials for treatment of malignant tumours. Basic research on HGF and Met has lead to drug discoveries in regenerative medicine and tumour biology. © The Authors 2015. Published by Oxford University Press on behalf of the Japanese Biochemical Society. All rights reserved

Helping-Like Behaviour in Mice Towards Conspecifics Constrained Inside Tubes

Prosocial behaviour, including helping behaviour, benefits others. Recently, helping-like behaviour has been observed in rats, but whether it is oriented towards rescue, social contact with others, or other goals remains unclear. Therefore, we investigated whether helping-like behaviour could be observed in mice similar to that in rats. Because mice are social animals widely used in neuroscience, the discovery of helping-like behaviour in mice would be valuable in clarifying the psychological and biological mechanisms underlying pro-sociability. We constrained mice inside tubes. Subject mice were allowed to move freely in cages with tubes containing constrained conspecifics. The subject mice released both cagemates and stranger mice but did not engage in opening empty tubes. Furthermore, the same behaviour was observed under aversive conditions and with anesthetised conspecifics. Interestingly, hungry mice opened the tubes containing food before engaging in tube-opening behaviour to free constrained conspecifics. Mice showed equal preferences for constrained and freely moving conspecifics. We demonstrated for the first time that mice show tube-opening behaviour. Furthermore, we partly clarified the purpose and motivation of this behaviour. An effective mouse model for helping-like behaviour would facilitate research on the mechanisms underlying prosocial behaviour

Attenuated Sensory Deprivation-induced Changes of Parvalbumin Neuron Density in the Barrel Cortex of FcγRllB-deficient Mice

Recent studies have demonstrated the important role of immune molecules in the development of neuronal circuitry and synaptic plasticity. We have detected the presence of FcγRllB protein in parvalbumin- containing inhibitory interneurons (PV neurons). In the present study, we examined the appearance of PV neurons in the barrel cortex and the effect of sensory deprivation in FcγRllB-deficient mice (FcγRllB-/-) and wild-type mice. There was no substantial difference in the appearance of PV neurons in the developing barrel cortex between FcγRllB-/- and wild-type mice. Sensory deprivation from immediately after birth (P0) or P7 to P12-P14 induced an increase in PV neurons. In contrast, sensory deprivation from P7 or P14 to P28, but not from P21 to P28, decreased PV neurons in wild-type mice. However, sensory deprivation from P0 or P7 to P12-P14 did not increase PV neurons and sensory deprivation from P7 or P14 to P28 did not decrease or only modestly decreased PV neurons in FcγRllB-/- mice. The results indicate that expression of PV is regulated by sensory experience and the second and third postnatal weeks are a sensitive period for sensory deprivation, and suggest that FcγRllB contributes to sensory experience-regulated expression of PV

Layer-specific expression of extracellular matrix molecules in the mouse somatosensory and piriform cortices

In the developing central nervous system (CNS), extracellular matrix (ECM) molecules have regulating roles such as in brain development, neural-circuit maturation, and synaptic-function control. However, excluding the perineuronal net (PNN) area, the distribution, constituent elements, and expression level of granular ECM molecules (diffuse ECM) present in the mature CNS remain unclear. Diffuse ECM molecules in the CNS share the components of PNNs and are likely functional. As cortical functions are greatly region-dependent, we hypothesized that ECM molecules would differ in distribution, expression level, and components in a region- and layer-dependent manner. We examined the layer-specific expression of several chondroitin sulfate proteoglycans (aggrecan, neurocan, and brevican), tenascin-R, Wisteria floribunda agglutinin (WFA)-positive molecules, hyaluronic acid, and link protein in the somatosensory and piriform cortices of mature mice. Furthermore, we investigated expression changes in WFA-positive molecules due to aging. In the somatosensory cortex, PNN density was particularly high at layer 4 (L4), but not all diffuse ECM molecules were highly expressed at L4 compared to the other layers. There was almost no change in tenascin-R and hyaluronic acid in any somatosensory-cortex layer. Neurocan showed high expression in L1 of the somatosensory cortex. In the piriform cortex, many ECM molecules showed higher expression in L1 than in the other layers. However, hyaluronic acid showed high expression in deep layers. Here, we clarified that ECM molecules differ in constituent elements and expression in a region- and layer-dependent manner. Region-specific expression of ECM molecules is possibly related to functions such as region-specific plasticity and vulnerability

A Retinoid X Receptor Agonist Directed to the Large Intestine Ameliorates T-Cell-Mediated Colitis in Mice

Retinoid X receptor (RXR) is a nuclear receptor that heterodimerizes with several nuclear receptors, integrating ligand-mediated signals across the heterodimers. Synthetic RXR agonists have been developed to cure certain inflammatory diseases, including inflammatory bowel diseases (IBDs). However, pre-existing RXR agonists, which are lipophilic and readily absorbed in the upper intestine, cause considerable adverse effects such as hepatomegaly, hyperlipidemia, and hypothyroidism. To minimize these adverse effects, we have developed an RXR agonist, NEt-3IB, which has lipophilic and thus poorly absorptive properties. In this study, we evaluated the effects of NEt-3IB in an experimental murine colitis model induced through the adoptive transfer of CD45RB(high)CD4(+) T cells. Pharmacokinetic studies demonstrated that the major portion of NEt-3IB was successfully delivered to the large intestine after oral administration. Notably, NEt-3IB treatment suppressed the development of T cell-mediated chronic colitis, as indicated by improvement of wasting symptoms, inflammatory infiltration, and mucosal hyperplasia. The protective effect of NEt-3IB was mediated by the suppression of IFN-gamma-producing Th1 cell expansion in the colon. In conclusion, NEt-3IB, a large intestine-directed RXR agonist, is a promising drug candidate for IBDs