Where did the super-small sized large bowel advanced cancer come from?

Our study suggested that the super-small sized (less than 15 mm in maximum diameter) large bowel advanced cancers, which were sometimes found, were derived from the superficial depressed-type or flat elevation-type of the colorectal early cancers, not polyp-type of those

Phorbol ester impairs electrical excitation of rat pancreatic beta-cells through PKC-independent activation of K(ATP) channels

BACKGROUND: Phorbol 12-myristate 13-acetate (PMA) is often used as an activating phorbol ester of protein kinase C (PKC) to investigate the roles of the kinase in cellular functions. Accumulating lines of evidence indicate that in addition to activating PKC, PMA also produces some regulatory effects in a PKC-independent manner. In this study, we investigated the non-PKC effects of PMA on electrical excitability of rat pancreatic β-cells by using patch-clamp techniques. RESULTS: In current-clamp recording, PMA (80 nM) reversibly inhibited 15 mM glucose-induced action potential spikes superimposed on a slow membrane depolarization and this inhibition can not be prevented by pre-treatment of the cell with a specific PKC inhibitor, bisindolylmaleimide (BIM, 1 μM). In the presence of a subthreshold concentration (5.5 mM) of glucose, PMA hyperpolarized β-cells in a concentration-dependent manner (0.8–240 nM), even in the presence of BIM. Based on cell-attached single channel recordings, PMA increased ATP-sensitive K(+) channel (K(ATP)) activity. Based on inside-out patch-clamp recordings, PMA had little effect on K(ATP) activity if no ATP was in the bath, while PMA restored K(ATP) activity that was suppressed by 10 μM ATP in the bath. In voltage-clamp recording, PMA enhanced tolbutamide-sensitive membrane currents elicited by repetitive ramp pulses from -90 to -50 mV in a concentration-dependent manner, and this potentiation could not be prevented by pre-treatment of cell with BIM. 4α-phorbol 12,13-didecanoate (4α-PDD), a non-PKC-activating phorbol ester, mimicked the effect of PMA on both current-clamp and voltage-clamp recording configurations. With either 5.5 or 16.6 mM glucose in the extracellular solution, PMA (80 nM) increased insulin secretion from rat islets. However, in islets pretreated with BIM (1 μM), PMA did not increase, but rather reduced insulin secretion. CONCLUSION: In rat pancreatic β-cells, PMA modulates insulin secretion through a mixed mechanism: increases insulin secretion by activation of PKC, and meanwhile decrease insulin secretion by impairing β-cell excitability in a PKC-independent manner. The enhancement of K(ATP) activity by reducing sensitivity of K(ATP) to ATP seems to underlie the PMA-induced impairment of β-cells electrical excitation in response to glucose stimulation

Clinical Evaluation of the Peroral Cholangioscopy Using a New Videoscope

Peroral cholangioscopy (PCS) has been performed in 22 cases using XCHF-B200 (Olympus Optical Co.) since June 1995 and in 77 cases using CHF-B20 (Olympus Optical Co.) after EST from Jan. 1989. XCHF-B200 has a longer rigid portion of distal end and a smaller channel diameter than CHF-B20. The successful rate of PCS using XCHF-B200 (82%) was lower than that of CHF-B20 (89%). The vascular pattern and fine vertical groove of the bile duct mucosa were shown more clearly on the photographs obtained with XCHF-B200 than those obtained with CHF-B20. However, not enough biopsy specimens could be obtained because the channel diameter of XCHF-B200 was rather small

Near-optimal stochastic MIMO signal detection with a mixture of t-distribution prior

Multiple-input multiple-output (MIMO) systems will play a crucial role in future wireless communication, but improving their signal detection performance to increase transmission efficiency remains a challenge. To address this issue, we propose extending the discrete signal detection problem in MIMO systems to a continuous one and applying the Hamiltonian Monte Carlo method, an efficient Markov chain Monte Carlo algorithm. In our previous studies, we have used a mixture of normal distributions for the prior distribution. In this study, we propose using a mixture of t-distributions, which further improves detection performance. Based on our theoretical analysis and computer simulations, the proposed method can achieve near-optimal signal detection with polynomial computational complexity. This high-performance and practical MIMO signal detection could contribute to the development of the 6th-generation mobile network.Comment: to be published in the 2023 IEEE Global Communications Conference (GLOBECOM

Nanometer-thin TiO2 enhances skeletal muscle cell phenotype and behavior

Ken Ishizaki*, Yoshihiko Sugita*, Fuminori Iwasa, Hajime Minamikawa, Takeshi Ueno, Masahiro Yamada, Takeo Suzuki, Takahiro OgawaLaboratory for Bone and Implant Sciences, The Jane and Jerry Weintraub Center for Reconstructive Biotechnology, Division of Advanced Prosthodontics, Biomaterials and Hospital Dentistry, UCLA School of Dentistry, Los Angeles, CA, USA*Authors contributed equally to this workBackground: The independent role of the surface chemistry of titanium in determining its biological properties is yet to be determined. Although titanium implants are often in contact with muscle tissue, the interaction of muscle cells with titanium is largely unknown. This study tested the hypotheses that the surface chemistry of clinically established microroughened titanium surfaces could be controllably varied by coating with a minimally thin layer of TiO2 (ideally pico-to-nanometer in thickness) without altering the existing topographical and roughness features, and that the change in superficial chemistry of titanium is effective in improving the biological properties of titanium.Methods and results: Acid-etched microroughened titanium surfaces were coated with TiO2 using slow-rate sputter deposition of molten TiO2 nanoparticles. A TiO2 coating of 300 pm to 6.3 nm increased the surface oxygen on the titanium substrates in a controllable manner, but did not alter the existing microscale architecture and roughness of the substrates. Cells derived from rat skeletal muscles showed increased attachment, spread, adhesion strength, proliferation, gene expression, and collagen production at the initial and early stage of culture on 6.3 nm thick TiO2-coated microroughened titanium surfaces compared with uncoated titanium surfaces.Conclusion: Using an exemplary slow-rate sputter deposition technique of molten TiO2 nanoparticles, this study demonstrated that titanium substrates, even with microscale roughness, can be sufficiently chemically modified to enhance their biological properties without altering the existing microscale morphology. The controllable and exclusive chemical modification technique presented in this study may open a new avenue for surface modifications of titanium-based biomaterials for better cell and tissue affinity and reaction.Keywords: nanotechnology, orthopedic implants, molten TiO2 nanoparticles, surface chemistr

Multicascade-linked synthetic wavelength digital holography using an optical-comb-referenced frequency synthesizer

Digital holography (DH) is a promising method for non-contact surface topography because the reconstructed phase image can visualize the nanometer unevenness in a sample. However, the axial range of this method is limited to the range of the optical wavelength due to the phase wrapping ambiguity. Although the use of two different wavelengths of light and the resulting synthetic wavelength, i.e., synthetic wavelength DH, can expand the axial range up to a few tens of microns, this method is still insufficient for practical applications. In this article, a tunable external cavity laser diode phase-locked to an optical frequency comb, namely, an optical-comb-referenced frequency synthesizer, is effectively used for multiple synthetic wavelengths within the range of 32 um to 1.20 m. A multiple cascade link of the phase images among an optical wavelength (= 1.520 um) and 5 different synthetic wavelengths (= 32.39 um, 99.98 um, 400.0 um, 1003 um, and 4021 um) enables the shape measurement of a reflective millimeter-sized stepped surface with the axial resolution of 34 nm. The axial dynamic range, defined as the ratio of the maximum axial range (= 0.60 m) to the axial resolution (= 34 nm), achieves 1.7*10^8, which is much larger than that of previous synthetic wavelength DH. Such a wide axial dynamic range capability will further expand the application field of DH for large objects with meter dimensions.Comment: 19 pages, 7 figure

Neutron Shielding Design of Infrared Imaging Video Bolometer for LHD Deuterium Experiment

InfraRed imaging video bolometer (IRVB) is a powerful diagnostic for the plasma radiation measurement. Study on plasma radiation phenomena, e.g., plasma detachment, is one of the crucial issues to realize a fusion reactor. In order to apply the IRVB to such a study, a shielding is required to protect an IR camera from neutron irradiation. In the large helical device (LHD), deuterium experiment has started in 2017. Then, the shielding was designed using MCNP6 code with the 3-D modeling of LHD. The guideline of the neutron flux for the design was determined by the operational experience in JT-60U tokamak and by the result of the irradiation in OKTAVIAN. The strong neutron flux due to the location close to the vacuum vessel and the influx through the lens hole were reduced sufficiently. The designed shielding was applied to the LHD deuterium experiments and the IRVB with the shielding could be operated successfully without any dead pixels in the neutron emission rate up to 3.3×10 15 n·s -1 , which is the maximum rate in the first experimental campaign and in the total neutron emission of 3.6×10 18 n. These correspond to the neutron emission rate of 2.9×10 7 n·s -1 and the total neutron emission of 3.2 × 10 10 n at around the IR camera

歯の形態形成に関与する新規遺伝子の解明

Tooth development is controlled by body plan during the fetal period, the generation of teeth from tooth germ is induced by the epithelial-mesenchymal interaction. Spatiotemporal regulation of tooth morphogenesis is supported by gene expression. Although many of the genes involved in tooth development are known, the molecular mechanism underlying tooth morphogenesis is not completely understood. For a comprehensive understanding of tooth development, the elucidation of unknown genes is necessary. In this study, to identify unknown genes involved in tooth development, we performed genome-wide analysis at each stage of tooth development and identified 17 genes with high levels of expression and large changes in expression. In addition, we performed qPCR and in situ hybridization analyses to elucidate the spatiotemporal regulation, such as the regulation that occurs around or in the entire tooth germ, enamel knots, epithelium, and mesenchyme. These results show that these characteristic genes may play important roles in each time period or region of tooth development, and the elucidation of the functions of these genes will lead to an integrated understanding of the process of tooth development.博士（医学）・甲第790号・令和3年3月15日発行元である日本再生歯科医学会の許諾を得て登録（2021年6月29日付）ジャーナル公式サイト（日本再生歯科医学会HP内）：http://www.jarde.jp/zasshi/e/18-2-1.htm