Roles of insulin-like growth factors and their binding proteins in mouse tongue myogenesis

Tongue is a complex muscular organ constitued of several intrinsic and extrinsic muscles, and involved in several important physiological tasks such as suckling, swallowing, mastication, breathing and vocalizing. Tongue striated muscles have several unique characteristics that are different from other skeletal muscles such as limb and trunk muscles. The roles of hepatocyte growth factor and transforming growth factor α in tongue myogenesis differ from those in other skeletal muscles. Insulin-like growth factors(IGFs) and their binding proteins(IGFBPs) play essential roles in the develpment of trunk and limb skeletal muscles, but their roles in the development of tongue striated muscle have not been examined. Thus, the main purpose of the present study is to elucidate roles of IGFs and IGFBPs in the differentiation of mouse tongue myoblasts. ･･･Thesis (Ph. D. in Science)--University of Tsukuba, (B), no. 1812, 2002.3.25Includes bibliographical referencesTITLE,TABLE OF CONTENTS -- Abbreviations -- Abstract -- General Introduction -- Materials and Metyods -- Part 1. Differentiation and Maturation of Tongue Striated Muscles -- Part 2. nAChR Subunit Elimination and Swich in Tongue Striated Muscles -- Part 3. Expressions of IGF-I,II and Their Receptors during Development of Tongue -- Part 4. Effects of IGF-I,IGFBP4,5,6 and des(1-3)IGF-I on Differentiation of Cultured Tongue Myoblasts -- General Discussion -- Acknowledgements -- References -- Tables -- Figures and Legend

In Vitro Thermochemotherapy of Human Osteosarcoma Cells with Cis-Dichlorodiammineplatinum (II)

Human osteosarcoma cells (HuO-3Nl cells) and fibroblastic cells with normal human karyotype (HuO-3 cells) were derived from a patient with osteosarcoma. HuO-3N1 cells were more sensitive to heat treatment than HuO-3 cells. The combination of heat and cis-dichlorodiammineplatinum (II) (CDDP) exerted synergistic cytotoxity on HuO-3N1 cells, and was much less cytotoxic to HuO-3 cells than to HuO-3Nl cells. Therefore, thermochemotherapy with CDDP may be useful for treatment of human osteosarcoma

Characterization of SiPM Optical Crosstalk and its Dependence on the Protection-Window Thickness

Owing to their high photon detection efficiency, compactness, and low operating voltage, silicon photomultipliers (SiPMs) have found widespread application in many fields, including medical imaging, particle physics, and high-energy astrophysics. However, the so-called optical crosstalk (OCT) phenomenon of SiPMs is a major drawback to their adoption. Secondary infrared photons are emitted inside the silicon substrate spontaneously after the avalanche process caused by the primary incident photons, and they can be detected by the surrounding photodiodes. As a result large output pulses that are equivalent to multiple photoelectrons are observed with a certain probability (OCT rate), even for single-photon events, making the charge resolution worse and increasing the rate of accidental triggers by single-photon events in applications such as atmospheric Cherenkov telescopes. In our previous study, we found that the OCT rates of single-channel SiPMs was dependent on the thickness of their protection resin window, which may be explained by photon propagation inside the resin. In the present study, we measured the OCT rate of a multichannel SiPM and those of neighboring channels caused by photon propagation. Both OCT rates were found to be dependent on the protection-window thickness. We report our OCT measurements of a multichannel SiPM and comparisons with a ray-tracing simulation.Comment: Accepted for publication in the Proceedings of the 5th International Workshop on New Photon-Detectors (PD18

Bone morphogenetic protein-2 functions as a negative regulator in the differentiation of myoblasts, but not as an inducer for the formations of cartilage and bone in mouse embryonic tongue

<p>Abstract</p> <p>Background</p> <p>In vitro studies using the myogenic cell line C2C12 demonstrate that bone morphogenetic protein-2 (BMP-2) converts the developmental pathway of C2C12 from a myogenic cell lineage to an osteoblastic cell lineage. Further, in vivo studies using null mutation mice demonstrate that BMPs inhibit the specification of the developmental fate of myogenic progenitor cells. However, the roles of BMPs in the phases of differentiation and maturation in skeletal muscles have yet to be determined. The present study attempts to define the function of BMP-2 in the final stage of differentiation of mouse tongue myoblast.</p> <p>Results</p> <p>Recombinant BMP-2 inhibited the expressions of markers for the differentiation of skeletal muscle cells, such as myogenin, muscle creatine kinase (MCK), and fast myosin heavy chain (fMyHC), whereas BMP-2 siRNA stimulated such markers. Neither the recombinant BMP-2 nor BMP-2 siRNA altered the expressions of markers for the formation of cartilage and bone, such as osteocalcin, alkaline phosphatase (ALP), collagen II, and collagen X. Further, no formation of cartilage and bone was observed in the recombinant BMP-2-treated tongues based on Alizarin red and Alcian blue stainings. Neither recombinant BMP-2 nor BMP-2 siRNA affected the expression of inhibitor of DNA binding/differentiation 1 (Id1). The ratios of chondrogenic and osteogenic markers relative to glyceraldehyde-3-phosphate dehydrogenase (GAPDH, a house keeping gene) were approximately 1000-fold lower than those of myogenic markers in the cultured tongue.</p> <p>Conclusions</p> <p>BMP-2 functions as a negative regulator for the final differentiation of tongue myoblasts, but not as an inducer for the formation of cartilage and bone in cultured tongue, probably because the genes related to myogenesis are in an activation mode, while the genes related to chondrogenesis and osteogenesis are in a silencing mode.</p

Functional relationships between cyclodextrin glucanotransferase from an alkalophilic Bacillus and α-amylases Site-directed mutagenesis of the conserved two Asp and one Glu residues

AbstractComparison of the amino acid sequences of cyclodextrin glucanotransferases (CGTases) with those of α-amylases revealed that two Asp and one Glu residues, which are considered to be the catalytic residues in α-amylases, were also conserved in CGTases. To analyze the function of the three conserved amino acid residues in CGTases, site-directed mutagenesis was carried out. The three mutant CGTases, in which Asp229, Glu257 and Asp328 were individually replaced by Asn or Gln, completely lost both their starch-degrading and β-cyclodextrin-forming activities, whereas another mutant CGTase, in which Glu264 replaced by Gln, retained these activities. The three inactive enzymes retained the ability to be bound to starch. These results suggest that Asp229, Glu257 and Asp328 play an important role in the enzymatic reaction catalyzed by CGTase and that a similar catalytic mechanism is present in both CGTases and α-amylases

Free fatty acid receptors, G protein-coupled receptor 120 and G protein-coupled receptor 40, are essential for oil-induced gastric inhibitory polypeptide secretion

Aims/Introduction: Incretin hormone glucose‐dependent insulinotropic polypeptide/gastric inhibitory polypeptide (GIP) plays a key role in high‐fat diet‐induced obesity and insulin resistance. GIP is strongly secreted from enteroendocrine K cells by oil ingestion. G protein‐coupled receptor (GPR)120 and GPR40 are two major receptors for long chain fatty acids, and are expressed in enteroendocrine K cells. In the present study, we investigated the effect of the two receptors on oil‐induced GIP secretion using GPR120‐ and GPR40‐double knockout (DKO) mice. Materials and Methods: Global knockout mice of GPR120 and GPR40 were crossbred to generate DKO mice. Oral glucose tolerance test and oral corn oil tolerance test were carried out. For analysis of the number of K cells and gene expression in K cells, DKO mice were crossbred with GIP‐green fluorescent protein knock‐in mice in which visualization and isolation of K cells can be achieved. Results: Double knockout mice showed normal glucose‐induced GIP secretion, but no GIP secretion by oil. We then investigated the number of K cells and gene characteristics in K cells isolated from GIP‐green fluorescent protein knock‐in mice. Deficiency of both receptors did not affect the number of K cells in the small intestine or expression of GIP messenger ribonucleic acid in K cells. Furthermore, there was no significant difference in the expression of the genes associated with lipid absorption or GIP secretion in K cells between wild‐type and DKO mice. Conclusions: Oil‐induced GIP secretion is triggered by the two major fatty acid receptors, GPR120 and GPR40, without changing K‐cell number or K‐cell characteristics