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Sota Katsube,1 Satohiro Matsumoto,1 Masahiro Misawa,2 Nao Kakizawa,3 Ryo Hashimoto,1 Taku Mizutani,1 Keita Matsumoto,1 Shuhei Yoshikawa,1 Hirosato Mashima1 1Department of Gastroenterology, Jichi Medical University Saitama Medical Center, Saitama, Japan; 2Department of Obstetrics and Gynecology, Jichi Medical University Saitama Medical Center, Saitama, Japan; 3Department of General and Gastrointestinal Surgery, Jichi Medical University Saitama Medical Center, Saitama, JapanCorrespondence: Sota Katsube, Department of Gastroenterology, Jichi Medical University Saitama Medical Center, 1-847 Amanuma, Saitama, Omiya, 330-8503, Japan, Tel +81 48 647 2111, Fax +81 48 648 5188, Email m08029sk@jichi.ac.jpAbstract: The patient was a 50-year-old Japanese woman who was diagnosed with total-colitis-type ulcerative colitis (UC) at the age of 26 years. She was treated with mesalazine and azathioprine, and her disease activity was well controlled. At the age of 50 years, the patient was experiencing fever, abdominal pain, diarrhea, bloody stool, and anal pain, which led to a diagnosis of a relapse of UC. Although steroid therapy was administered and tended to improve her symptoms, fecaloid vaginal discharge occurred, and rectovaginal fistula (RVF) was confirmed. Colostomy was performed, and infliximab was initiated as maintenance therapy for UC. All symptoms improved, and RVF closure was confirmed 6 months after the initiation of infliximab. To date, she has been free from relapse of UC. There have been only a few reports of UC complicated by RVF, and this condition is often difficult to treat. To the best of our knowledge, no other case of UC complicated by RVF in which the fistula was closed after treatment with colostomy and infliximab has been previously reported; thus, our report of the present case is valuable to the literature.Keywords: ulcerative colitis, rectovaginal fistula, infliximab, colostomy

Katsunori Yogo,1 Masaki Misawa,2 Morihito Shimizu,2 Hidetoshi Shimizu,3 Tomoki Kitagawa,3 Ryoichi Hirayama,4 Hiromichi Ishiyama,5 Takako Furukawa,1 Hiroshi Yasuda6 1Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan; 2Health and Medical Research Institute, National Institute of Advanced Industrial Science & Technology (AIST), Tsukuba, Ibaraki, Japan; 3Department of Radiation Oncology, Aichi Cancer Center Hospital, Nagoya, Aichi, Japan; 4National Institute of Radiological Sciences (NIRS), National Institutes for Quantum and Radiological Science and Technology (QST), Chiba-shi, Chiba, Japan; 5Graduate School of Medical Science, Kitasato University, Sagamihara, Kanagawa, Japan; 6Department of Radiation Biophysics, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, JapanCorrespondence: Katsunori YogoNagoya University Graduate School of Medicine, 1-1-20 Daiko-Minami, Higashi-Ku, Nagoya, Aichi 461-8673, JapanTel +81 52 719 1103Fax +81 52 719 3172Email yogo@met.nagoya-u.ac.jpPurpose: Gold nanoparticles (AuNPs) are candidate radiosensitizers for medium-energy photon treatment, such as γ-ray radiation in high-dose-rate (HDR) brachytherapy. However, high AuNP concentrations are required for sufficient dose enhancement for clinical applications. Here, we investigated the effect of positively (+) charged AuNP radiosensitization of plasmid DNA damage induced by 192Ir γ-rays, and compared it with that of negatively (−) charged AuNPs.Methods: We observed DNA breaks and reactive oxygen species (ROS) generation in the presence of AuNPs at low concentrations. pBR322 plasmid DNA exposed to 64 ng/mL AuNPs was irradiated with 192Ir γ-rays via HDR brachytherapy. DNA breaks were detected by observing the changes in the form of the plasmid and quantified by agarose gel electrophoresis. The ROS generated by the AuNPs were measured with the fluorescent probe sensitive to ROS. The effects of positively (+) and negatively (−) charged AuNPs were compared to study the effect of surface charge on dose enhancement.Results: +AuNPs at lower concentrations promoted a comparable level of radiosensitization by producing both single-stranded breaks (SSBs) and double-stranded breaks (DSBs) than those used in cell assays and Monte Carlo simulation experiments. The dose enhancement factor (DEF) for +AuNPs was 1.3 ± 0.2 for SSBs and 1.5 ± 0.4 for DSBs. The ability of +AuNPs to augment plasmid DNA damage is due to enhanced ROS generation. While −AuNPs generated similar ROS levels, they did not cause significant DNA damage. Thus, dose enhancement using low concentrations of +AuNPs presumably occurred via DNA binding or increasing local +AuNP concentration around the DNA.Conclusion: +AuNPs at low concentrations displayed stronger radiosensitization compared to −AuNPs. Combining +AuNPs with 192Ir γ-rays in HDR brachytherapy is a candidate method for improving clinical outcomes. Future development of cancer cell-specific +AuNPs would allow their wider application for HDR brachytherapy.Keywords: gold nanoparticles, high-dose-rate brachytherapy, DNA damage, radiosensitization, 192Ir γ-rays, positively charged nanoparticles

CdZnTe (CZT) detectors are promising detectors, which have many good characteristics such as room temperature operation, reasonable energy resolution, high-detection efficiency to gamma rays, etc. However, energy resolution of CZT is governed by poor mobilities of charge carriers. Many researchers have tried to solve this problem. Among them, a clustering method has been recently proposed which is based on a digital signal processing of preamplifier output waveforms. In this method, we can classify signals according to their shapes and independently treat different shapes. In this paper, we report a new clustering algorithm with adaptive shaping time. The obtained energy resolution for [sup.137]Cs was improved to 5.4-keV full width at half maximum (FWHM) by applying this method. Index Terms--CdZnTe (CZT), clustering method, digital signal processing (DSP).