Toshikatsu Okumura

ORCID: 0000-0003-1810-007X
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About
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Research Areas
  • Gastrointestinal motility and disorders
  • Helicobacter pylori-related gastroenterology studies
  • Sleep and Wakefulness Research
  • Pancreatic and Hepatic Oncology Research
  • Regulation of Appetite and Obesity
  • Inflammatory Bowel Disease
  • Sleep and related disorders
  • Gastric Cancer Management and Outcomes
  • Peroxisome Proliferator-Activated Receptors
  • Stress Responses and Cortisol
  • Cholangiocarcinoma and Gallbladder Cancer Studies
  • Liver Disease Diagnosis and Treatment
  • Gastrointestinal Tumor Research and Treatment
  • Gastrointestinal disorders and treatments
  • Diet and metabolism studies
  • Gastroesophageal reflux and treatments
  • Cancer Genomics and Diagnostics
  • Neuropeptides and Animal Physiology
  • Colorectal Cancer Treatments and Studies
  • Neuroscience of respiration and sleep
  • Pancreatitis Pathology and Treatment
  • Metastasis and carcinoma case studies
  • Neuroendocrine Tumor Research Advances
  • Biochemical Analysis and Sensing Techniques
  • Dermatology and Skin Diseases

Asahikawa Medical University
2015-2024

The Japanese Society of Gastroenterological Surgery
2014-2023

Weatherford College
2020-2023

Japan Society for the Promotion of Science
2020

Sapporo Higashi Tokushukai Hospital
2020

Asahikawa University
2015

General Department of Preventive Medicine
2008-2013

Asahikawa Medical College Hospital
2002-2011

Kindai University
2000-2008

Otsuka (Japan)
1997

To identify predictive molecular markers for gemcitabine resistance, we investigated changes in the expression of four genes associated with transport and metabolism during development acquired resistance pancreatic cancer cell lines. The levels human equilibrative nucleoside transporter-1 (hENT1), deoxycytidine kinase (dCK), RRM1, RRM2 mRNA were analysed by real-time light cycler-PCR various subclones to gemcitabine. Real-time demonstrated that either RRM1 or progressively increased...

10.1038/sj.bjc.6603559 article EN cc-by-nc-sa British Journal of Cancer 2007-01-16

Pancreatic cancer is associated with an extremely poor prognosis, so new biomarkers that can detect the initial stages are urgently needed. The significance of serum microRNA (miR) levels in pancreatic neoplasm such as and intraductal papillary mucinous (IPMN) diagnosis remains unclear. We herein evaluated usefulness miRs enclosed exosomes (ExmiRs) diagnostic markers.The ExmiRs from patients (n = 32) or IPMN 29), without neoplasms (controls; n 22) were enriched using ExoQuick-TC™. expression...

10.1186/s12885-018-4006-5 article EN cc-by BMC Cancer 2018-01-31

Managing irritable bowel syndrome (IBS) has attracted international attention because single-agent therapy rarely relieves bothersome symptoms for all patients. The Japanese Society of Gastroenterology (JSGE) published the first edition evidence-based clinical practice guidelines IBS in 2015. Much more evidence accumulated since then, and new pharmacological agents non-pharmacological methods have been developed. Here, we report second JSGE-IBS comprising 41 questions including 12 background...

10.1007/s00535-020-01746-z article EN cc-by Journal of Gastroenterology 2021-02-04

We investigated the expression of peroxisome proliferator-activated receptor gamma (PPARgamma) and role PPARgamma in cell growth human gastric cancer cells. Reverse transcription-polymerase chain reaction, Northern blot Western analyses showed that a line, MKN45, expressed mRNA protein. Luciferase assay MKN45 cells troglitazone, selective ligand for PPARgamma, transactivated transcription proliferator response element-driven promoter. Troglitazone or pioglitazone, ligands inhibited...

10.1016/s0014-5793(99)00871-6 article EN FEBS Letters 1999-07-15

Although branch duct intraductal papillary-mucinous neoplasms (IPMNs) of the pancreas without mural nodules are frequently observed in asymptomatic subjects, natural history these lesions has never been studied. The aim this study was to elucidate IPMNs nodules.Eighty-two patients who had no apparent on initial examination were selected for follow-up. All subjects underwent examinations by imaging modalities including endoscopic retrograde pancreatography, and followed-up regular once or...

10.1136/gut.2007.129684 article EN Gut 2007-07-28

Although branch duct intraductal papillary mucinous neoplasms (BD-IPMNs) are slow-growing tumors with a favorable prognosis, the synchronous occurrence of pancreatic ductal adenocarcinomas (PDAs) in patients BD-IPMNs has been reported. This study was aimed to elucidate development PDAs long-term follow-up BD-IPMNs.We investigated 89 BD-IPMN who had no mural nodules and followed them up conservatively at least 2 years (median follow-up, 64 months; range, 25-158 months). All subjects underwent...

10.1097/mpa.0b013e3181b91cd0 article EN Pancreas 2009-12-17

Previous studies have indicated that serotonin-3-receptor antagonists might a sex-specific effect in patients with irritable bowel syndrome diarrhea (IBS-D). Alosetron has been approved for the treatment of only women, and ramosetron men. We performed randomized, placebo-controlled, phase 3 study to determine whether reduces symptoms IBS-D women.We prospective 576 female outpatients (according Rome III criteria), from February 2013 through 2014, at 70 academic Gastroenterology Departments...

10.1053/j.gastro.2015.10.047 article EN cc-by-nc-nd Gastroenterology 2015-11-07

Orexinergic neurones in the perifornical lateral hypothalamus project to structures of midbrain, including substantia nigra and mesopontine tegmentum. These areas contain mesencephalic locomotor region (MLR), pedunculopontine laterodorsal tegmental nuclei (PPN/LDT), which regulate atonia during rapid eye movement (REM) sleep. Deficiencies orexinergic system result narcolepsy, suggesting that these projections are concerned with switching between movements muscular atonia. The present study...

10.1113/jphysiol.2005.085829 article EN The Journal of Physiology 2005-08-26

Abstract The prognosis for patients with bile duct cancer (BDC) remains poor. Although BDC cells are essentially radioresistant, recent reports have suggested that radiation therapy, in addition to its palliative role the management of BDC, may improve patient survival. A better understanding mechanisms lead cellular radioresistance assist development more effective therapies based on radiotherapy combination radiosensitizing agents. serine/threonine kinase AKT/protein B, a downstream...

10.1158/0008-5472.can-03-1788 article EN Cancer Research 2004-05-15

The hedgehog (Hh) pathway has been implicated in the pathogenesis of cancer including pancreatic ductal adenocarcinoma (PDAC). Recent studies have suggested that oncogenic function Hh PDAC involves signaling stromal cells rather than cell autonomous effects on tumor cells. However, origin and nature type(s) are responsive to remained unknown. Since plays a crucial role during embryonic postnatal vasculogenesis, we speculated ligand may act vasculature specifically focusing bone marrow...

10.1371/journal.pone.0008824 article EN cc-by PLoS ONE 2010-01-20
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