Supersymmetric Baryogenesis in a Hybrid Inflation Model

We study baryogenesis in a hybrid inflation model which is embedded to the minimal supersymmetric model with right-handed neutrinos. Inflation is induced by a linear combination of the right-handed sneutrinos and its decay reheats the universe. The decay products are stored in conserved numbers, which are transported under the interactions in equilibrium as the temperature drops down. We find that at least a few percent of the initial lepton asymmetry is left under the strong wash-out due to the lighter right-handed (s)neutrinos. To account for the observed baryon number and the active neutrino masses after a successful inflation, the inflaton mass and the Majorana mass scale should be $10^{13}\,{\rm GeV}$ and ${\cal O}(10^{7}$-$10^{10})\,{\rm GeV}$, respectively.Comment: 19 pages, 2 figure

Development of an experimental method of systematically estimating protein expression limits in HEK293 cells

Protein overexpression sometimes causes cellular defects, although the underlying mechanism is still unknown. A protein's expression limit, which triggers cellular defects, is a useful indication of the underlying mechanism. In this study, we developed an experimental method of estimating the expression limits of target proteins in the human embryonic kidney cell line HEK293 by measuring the proteins' expression levels in cells that survived after the high-copy introduction of plasmid DNA by which the proteins were expressed under a strong cytomegalovirus promoter. The expression limits of nonfluorescent target proteins were indirectly estimated by measuring the levels of green fluorescent protein (GFP) connected to the target proteins with the self-cleaving sequence P2A. The expression limit of a model GFP was similar to 5.0% of the total protein, and sustained GFP overexpression caused cell death. The expression limits of GFPs with mitochondria-targeting signals and endoplasmic reticulum localization signals were 1.6% and 0.38%, respectively. The expression limits of four proteins involved in vesicular trafficking were far lower compared to a red fluorescent protein. The protein expression limit estimation method developed will be valuable for defining toxic proteins and consequences of protein overexpression

Effects of Bitter Receptor Antagonists on Behavioral Lick Responses of Mice

Bitter taste receptors TAS2Rs detect noxious compounds in the oral cavity. Recent heterologous expression studies reported that some compounds function as antagonists for human TAS2Rs. For examples, amino acid derivatives such as γ-aminobutyric acid (GABA) and Nα,Nα-bis(carboxymethyl)-L-Lysine (BCML) blocked responses to quinine mediated by human TAS2R4. Probenecid inhibited responses to phenylthiocarbamide mediated by human TAS2R38. In this study, we investigated the effects of these human bitter receptor antagonists on behavioral lick responses of mice to elucidate whether these compounds also function as bitter taste blockers. In short-term (10 s) lick tests, concentration-dependent lick responses to bitter compounds (quinine-HCl, denatonium and phenylthiourea) were not affected by the addition of GABA or BCML. Probenecid reduced aversive lick responses to denatonium and phenylthiourea but not to quinine-HCl. In addition, taste cell responses to phenylthiourea were inhibited by probenecid. These results suggest some bitter antagonists of human TAS2Rs can work for bitter sense of mouse

A Case Report of Intraductal Papillary-Mucinous Neoplasm of the Pancreas Showing Morphologic Transformation during Followup Periods

A 64-year-old man underwent MRCP for further examination of gallbladder stones and IPMN of branch-type (IPMN-Br) was pointed out. Yearly MRCP had revealed the gradual increase of the cystic components, marked dilation of the main pancreatic duct (MPD), and filling defects in the MPD. After follow-up for three years, he underwent pancreatoduodenectomy. Histologically, the dilated MPD and connecting dilated branch ducts were filled with nodular growth of tumor cells consisting of gastric-type adenoma with pyloric gland-like structures. In the MPD, a transition from gastric-type adenoma to intestinal-type carcinoma was observed. In addition, in a dilated branch duct, some components of intestinal-type carcinoma with marked arborizing structures were observed. A minimally invasion was observed around branch ducts. Immunohistochemistry revealed diffuse nuclear accumulation of PCNA and Ki67 in the tumor cells of branch dusts. Our observations suggest that the secondary infiltration to the MPD of IPMN-Br and IPMN-Br possesses malignant potential for microinvasion