S Ota

Japan Red Cross Fukuoka Hospital, Hukuoka, Fukuoka, Japan

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Publications (128)606.69 Total impact

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    ABSTRACT: To investigate the usefulness of anti-ulcer drugs for the prevention and treatment of low-dose aspirin-induced peptic ulcer. Upper gastrointestinal endoscopy was performed in 68 patients receiving daily low-dose aspirin (81 or 100 mg/day). The endoscopic findings were classified according to the Lanza score, and the scores were compared between groups categorized according to the concomitant use of anti-ulcer drugs and the types of drugs used. In another study, 31 hemorrhagic peptic ulcer patients who had been receiving low-dose aspirin were enrolled. The patients were randomly classified into the proton pump inhibitor (PPI)-treated group and the H2 receptor antagonist (H2RA)-treated group. The administration of low-dose aspirin was continued concomitantly, and endoscopic examinations were performed 8 wk later. The Lanza scores (mean +/- SD) of the gastro-mucosal lesions were 1.0 +/- 1.9 and 1.9 +/- 2.3 in 8 and 16 patients receiving prevention therapy with a PPI and an H2RA, respectively. Both scores were significantly smaller than the scores in 34 patients who were not receiving prevention therapy (4.7 +/- 1.0) and in 10 patients receiving cytoprotective anti-ulcer drugs (4.3 +/- 1.6). In the prospective study, 18 and 13 patients received a PPI and an H2RA, respectively. Endoscopic examinations revealed that the tissue in the region of the gastro-mucosal lesions had reverted to normal in all patients in the PPI-treated group and in 12 patients (92%) in the H2RA-treated group; no significant differences were observed between the groups. H2RA therapy was effective for both the prevention and treatment of low-dose aspirin-induced peptic ulcer, similar to the effects of PPIs, while cytoprotective anti-ulcer drugs were ineffective in preventing ulceration.
    World Journal of Gastroenterology 03/2009; 15(6):727-31. · 2.55 Impact Factor
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    ABSTRACT: Background: Argon plasma coagulation (APC) can achieve an effective coagulation of large areas with a relatively shallow but well-controlled and uniform coagulation depth. There are only a few reports of APC therapy applied to bleeding peptic ulcers, especially ulcers with exposed vessels.Methods: The aim of this study is to evaluate the usefulness of APC as a means of achieving endoscopic hemostasis for bleeding gastroduodenal ulcers. Thirty-nine patients having these ulcers were treated with APC.Results: The success rates for initial hemostasis and complete hemostasis with APC are 87% and 97.4%, respectively. These results are almost equal to those of injection therapy and hemoclip. Six cases that re-bled after other hemostatic procedures obtained complete hemostasis finally with APC. In one ineffective case of APC, complete endoscopic hemostasis was achieved with hemoclip.Conclusion: Argon plasma coagulation therapy is an effective therapeutic alternative in endoscopic hemostasis for bleeding peptic ulcers.
    Digestive Endoscopy 09/2008; 14(3):99 - 102. · 1.61 Impact Factor
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    ABSTRACT: Mesenchymal-epithelial interactions are important in the gastric mucosal repair. However, specific factors responsible for such interactions have not been established. In the present study, keratinocyte growth factor (KGF) significantly stimulated proliferation of gastric epithelial cells dose dependently and synergistically with hepatocyte growth factor (HGF), epidermal growth factor (EGF) and insulin. Restitution of gastric epithelial monolayers was also assessed, using a round wound restitution model. Keratinocyte growth factor facilitated the restitution of gastric epithelial cells significantly but did not have any effects on gastric fibroblasts. Keratinocyte growth factor receptor mRNA was expressed by gastric epithelial cells, indicating that these effects were elicited by the specific receptor mediated pathway. Northern blot analysis revealed the expression of KGF mRNA in gastric fibroblasts but not in gastric epithelial cells, indicating the production of KGF. These results suggest that KGF might be involved in gastric mucosal repair, through mesenchymal-epithelial interaction.
    Journal of Gastroenterology and Hepatology 06/2008; 11(11):1089 - 1096. · 3.33 Impact Factor
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    ABSTRACT: Cholestatic hepatocellular carcinoma, which grows into the bile duct and causes obstructive jaundice, is rare and difficult to diagnose. A case is presented in which cholestatic hepatocellular carcinoma was detected by deposit of Lipiodol. This is also the first case that was successfully treated by endoscopic retrograde biliary drainage and transcatheter arterial embolization.
    Journal of Gastroenterology and Hepatology 03/2008; 7(2):154 - 156. · 3.33 Impact Factor
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    ABSTRACT: A 52-year-old man undergoing distal gastrectomy for gastric cancer in July 1998 was found to have a 0-IIa type gastric tumor near EC junction in January 2005. Histological examination showed the tumor was moderately differentiated adenocarcinoma. As the tumor was diagnosed as mucosal cancer, endoscopic mucosal dissection was performed. But pathological findings showed the depth of cancer cell invasion into deep submucosal layer. Then total resection of remnant stomach was performed. Both tumors were diagnosed as EBV-associated carcinoma. It is speculated that the mucosa changing after initial operation would give risk to a new occurrence of EBV-associated remnant gastric carcinoma. And then follow up after operation is important. Although some cases of EBV-associated remnant gastric carcinoma is found for short period after the primary surgery, our case second primary cancer was found 7 year after primary surgery. Long term follow-up by Endoscopy seems to be important.
    Nippon Shokakibyo Gakkai zasshi The Japanese journal of gastro-enterology 01/2008; 104(12):1728-32.
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    ABSTRACT: In 1979, a new mechanism of gastric defense named cytoprotection was followed by numerous reports elucidating this interesting and important phenomenon. During this decade, however, the concept and definition of gastric cytoprotection have been modified from the morphological and ultrastructural viewpoints. This review attempts to describe the concept and mechanisms of cytoprotection as well as its pathophysiological features. Specifically, in vitro studies using isolated cells or monolayer cultured cells as well as molecular investigations of signal transduction system have been documented.
    Acta pathologica japonica 01/2008; 43(1-2):2-10.
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    ABSTRACT: Studies in Western populations have shown the association of nonsteroidal anti-inflammatory drugs (NSAIDs) and upper gastrointestinal bleeding (UGIB). The role of Helicobacter pylori infection in NSAIDs-related UGIB remains to be studied. We conducted a case-control study in Japan to investigate these related topics. Cases of UGIB due to duodenal or gastric ulcer, or gastritis were identified in 14 study hospitals in various areas of Japan. For each case, two controls were identified from population registries in the same district. Information on drugs and other risk factors was obtained from 175 cases and 347 controls by telephone interviews. Anti-H. pylori antibody in the urine was measured in a single laboratory for all the cases and 225 controls. The odds ratio (OR) of UGIB was 5.5 for aspirin and 6.1 for other NSAIDs (NANSAIDs) (p<0.01). The OR for regular use was higher than for occasional use both for aspirin (7.7 vs 2.0) and NANSAIDs (7.3 vs 4.1). Loxoprofen (5.9), frequently used in Japan as a safe 'prodrug', was significantly associated with UGIB. The odds ratio for H. pylori infection was 4.9 and the relative excess risk due to the interaction between H. pylori and the use of NSAID was 1.2 (95% CI: -5.8-8.1). NSAIDs including loxoprofen increase the risk of UGIB in Japan as in Western countries, with a similar magnitude of association. There was no evidence of biological interaction between NSAIDs and H. pylori infection.
    European Journal of Clinical Pharmacology 10/2006; 62(9):765-72. · 2.74 Impact Factor
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    ABSTRACT: Depletion of granulocytes and monocytes (GM) by selective apheresis (GMA) with an Adacolumn exerts an anti-inflammatory effect in patients with ulcerative colitis (UC) or rheumatoid arthritis. However, the mechanism of the anti-inflammatory effect of GMA is not fully understood yet. We investigated the effect of GMA on the plasma concentration of interleukin-1 receptor antagonist (IL-1ra), a potent anti-inflammatory cytokine. Twenty-six patients with active UC received GMA at one session per week for 5 consecutive weeks. Clinical response was defined as Deltaclinical activity index (DeltaCAI=CAI at entry - CAI at post)>or=4, while clinical remission was defined as CAI<or=4. Twenty-one of twenty-six patients (80.8%) responded to GMA. In the first session, plasma from responder patients showed a significant (P < 0.01) increase in IL-1ra in the Adacolumn outflow. In contrast, there was no change in IL-1ra in nonresponders. In conclusion, release of IL-1ra during GMA might be one mechanism of clinical efficacy associated with this therapy.
    Digestive Diseases and Sciences 09/2006; 51(9):1525-31. · 2.26 Impact Factor
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    ABSTRACT: Endoscopic mucosal resection (EMR) offers curative treatment for patients with node-negative early gastric carcinoma of less than 2 cm without ulceration or ulceration scar. Follow-up biopsies are frequently performed to ensure the absence of residual neoplasia. We performed a retrospective analysis of post-EMR biopsies from 33 patients who underwent gastric EMR. Histologic changes included inflammation (100%), stromal edema (97.0%), foveolar hyperplasia (78.8%), ectatic vessels (66.7%), epithelial atypia (60.6%), increased glandular mitoses (57.6%), epithelial anisonucleosis (54.5%), fibrinopurulent materials (51.5%), ischemia (48.5%), stromal hemorrhage (33.3%), mucin depletion (12.1%), clear cell degeneration (15.2%), and signet-ring cell-like change (6.1%). Especially, clear cell degeneration and signet-ring cell-like change were conspicuous in the area of ischemia. Residual adenocarcinomas were noted in 4 of 33 cases, and consistently showed high nuclear-to-cytoplasmic ratio with high glandular density. Glandular clear cell degeneration and/or signet-ring cell-like change were worrisome and sometimes difficult to be distinguished from residual neoplastic glands. However, these degenerative glands were usually embedded in a nondesmoplastic stroma and showed anisonucleosis of glandular epithelia. Mimics of residual adenocarcinoma, namely clear cell degeneration and signet-ring cell-like change should be judiciously assessed to avoid unnecessary surgery.
    American Journal of Surgical Pathology 06/2006; 30(5):650-6. · 4.87 Impact Factor
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    ABSTRACT: Endoscopic mucosal resection (EMR), which is advocated for the treatment of early (superficial) gastroesophageal neoplasms, has also been alluded to represent a superior diagnostic and staging modality. We compared the diagnostic concordance of preceding biopsies with EMR specimens in 31 gastric and 10 esophageal EMRs consisting of 6 low-grade and 12 high-grade dysplasias, 21 intramucosal adenocarcinomas, and 2 submucosal invasive adenocarcinomas. Discrepancies were considered as either major or minor if the histologic grades differed by 2 or more, or by only 1, respectively. Discrepant and concordant cases were compared with regard to the size of lesion (maximum dimension and surface area), number of biopsy fragments, and extent of biopsy sampling (ratio between lesion size and number of biopsy fragments). These same variables were used to evaluate the differences seen between gastric and esophageal cases. Of the 41 cases, 16 (39%) had discrepant diagnoses, including 14 gastric and 2 esophageal neoplasms. A major discrepancy was seen in 2% of the cases (n = 1, gastric) and a minor discrepancy, in 15 cases. All but 2 of the discrepant cases were found to have a higher grade on EMR. The average number of biopsy fragments was 4.4 in both concordant and discrepant groups. The maximal dimension, surface area, and biopsy sampling ratios of the lesion were significantly greater in the discrepant cases than in the concordant cases. The esophageal cases trended toward having smaller size and a significantly extensive biopsy sampling. We conclude that EMR is superior to biopsy for diagnosing superficial gastroesophageal tumors. Discrepancies between the specimens occur in larger lesions (>10 mm) with less extensive biopsy sampling. EMR can substantially modify the diagnostic grade of a lesion and therefore facilitate optimal therapeutic decisions by avoiding undertreatment and overtreatment based on inaccurate grading and staging.
    American Journal of Surgical Pathology 01/2006; 30(1):114-8. · 4.87 Impact Factor
  • Shinichi Ota, Sayaka Nakajima, Hiromi Bamba
    Nippon rinsho. Japanese journal of clinical medicine 12/2005; 63 Suppl 11:565-8.
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    ABSTRACT: The mechanisms responsible for impaired regenerative ability after hepatic resection observed in chronic liver disease are not fully understood. We have examined the relationships between an altered expression of cell cycle-related proteins in regenerating liver after partial hepatectomy and the impaired regenerative process observed in fibrotic and cirrhotic rats. We performed 70% partial hepatectomy in both control and porcine serum-induced fibrotic rats, and 45% partial hepatectomy in thioacetamide-induced cirrhotic rats because of the high mortality associated with 70% partial hepatectomy. Liver regeneration was monitored by proliferating cell nuclear antigen labeling index and the expression of G1 regulatory cell cycle-related proteins was determined by immunoblot analysis. Compared with controls, hepatocyte DNA synthesis, and induction of cyclin D1 and p21(CIP1) proteins were delayed but not suppressed in porcine serum-induced fibrotic rats and markedly inhibited in thioacetamide-induced cirrhotic rats. p27(KIP1) protein levels were unaffected by partial hepatectomy and did not differ among all three groups. Two distinct rat models of liver fibrosis and cirrhosis showed markedly different proliferative responses after partial hepatectomy. The delay or failure of cyclin D1 induction, but not the increase of p21(CIP1) or p27(KIP1) might be responsible for their impaired liver regeneration.
    Journal of Gastroenterology and Hepatology 09/2005; 20(8):1198-205. · 3.33 Impact Factor
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    ABSTRACT: The aim of this study is to evaluate the usefulness of gastroesophageal reflux (GER) scintigraphy using the knee-chest (KC) position for the diagnosis of gastroesophageal reflux disease (GERD). The study subjects were 37 patients with GERD and 8 healthy volunteers (control group). Endoscopically observed esophageal mucosal breaks were evaluated with the Los Angeles classification. For GER scintigraphy, the subjects ingested liquid yogurt labeled with 99mTc-diethylene triamine pentaacetic acid (99mTc-DTPA) and water. Imaging was performed in the supine and KC position, and GER was graded as 1-4 according to the extent of GER assessed by scintigraphy. GER scintigraphy revealed no reflux in the control group (specificity: 100%). In the supine position, gastroesophageal reflux was observed in 49% of the patients with GERD, compared to 76% in the KC position. 21 of 23 (91%) patients with erosive esophagitis were shown to have GER with scintigraphy. GER scintigraphy revealed severe reflux (grade 3 or 4) (83%, 10/12) in the patients who had severe mucosal breaks (LA grade C or D). GER scintigraphy detected grade 1 or 2 reflux in 7 of the 14 patients who were endoscopically negative. There was a correlation between the endoscopically determined severity of mucosa and the reflux grade which was determined with GER scintigraphy. GER scintigraphy can detect gastroesophageal reflux with a high sensitivity in the KC position and might be a useful method in the screening and assessment of the severity of this disease. This method would be useful for the diagnosis of GERD in endoscopically negative patients.
    Annals of Nuclear Medicine 07/2005; 19(4):291-6. · 1.41 Impact Factor
  • Gastrointestinal Endoscopy - GASTROINTEST ENDOSCOP. 01/2005; 61(5).
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    ABSTRACT: Endoscopic mucosal resection of gastric neoplasms is a curative technique that avoids surgery and its potential complications. Infrequently performed in the West, the limitations, pitfalls and challenges provided by this new therapeutic modality are not well known by general surgical pathologists. We evaluated a series of 39 endoscopic mucosal resections and assessed the correlation between original biopsies and final diagnoses, depth of excision, status of deep and lateral margins, artifactual changes and recurrence rate. The tumors consisted of 24 intramucosal carcinomas, six high-grade dysplasias, eight low-grade dysplasias and one submucosal invasive carcinoma. The preresection diagnoses corresponded to the final evaluation in 63% of the cases with previous biopsies. In 37% of the cases, the biopsies under-diagnosed the neoplasia. The rate of positive margins was 38%. Iatrogenic changes, that is, intramucosal hemorrhage and electrodiathermic burn, were noted in 44% of the cases but hindered the pathologic evaluation in only 10% of the cases. Persistence or recurrence was observed in only seven cases and there was no progression to advanced adenocarcinoma. Based on our experience, we offer some recommendations in order to provide optimal pathologic analysis of endoscopic mucosal resection specimens.
    Modern Pathology 02/2004; 17(1):2-8. · 5.25 Impact Factor
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    ABSTRACT: Endoscopic mucosal resection of gastric neoplasms is a curative technique that avoids surgery and its potential complications. Infrequently performed in the West, the limitations, pitfalls and challenges provided by this new therapeutic modality are not well known by general surgical pathologists. We evaluated a series of 39 endoscopic mucosal resections and assessed the correlation between original biopsies and final diagnoses, depth of excision, status of deep and lateral margins, artifactual changes and recurrence rate. The tumors consisted of 24 intramucosal carcinomas, six high-grade dysplasias, eight low-grade dysplasias and one submucosal invasive carcinoma. The preresection diagnoses corresponded to the final evaluation in 63% of the cases with previous biopsies. In 37% of the cases, the biopsies under-diagnosed the neoplasia. The rate of positive margins was 38%. Iatrogenic changes, that is, intramucosal hemorrhage and electrodiathermic burn, were noted in 44% of the cases but hindered the pathologic evaluation in only 10% of the cases. Persistence or recurrence was observed in only seven cases and there was no progression to advanced adenocarcinoma. Based on our experience, we offer some recommendations in order to provide optimal pathologic analysis of endoscopic mucosal resection specimens.Keywords: endoscopic mucosal resection, stomach, dysplasia, early gastric cancer, therapy
    Modern Pathology 11/2003; 17(1):2-8. · 5.25 Impact Factor
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    ABSTRACT: Cyclooxygenase (COX)-2, an inducible isoform of prostaglandin synthetase, has been reported to be a key molecular target of colon cancer prevention by nonsteroidal anti-inflammatory drugs. Recently, it has been shown that Helicobacter pylori (H. pylori) could induce COX-2 together with inflammatory cytokines. Although human hyperplastic gastric polyps disappeared or decreased in number and size after eradication of H. pylori, the mechanisms in this step, especially the roles of COX-2, have not been yet elucidated. The aims of the present study were to examine the expression and localization of COX-2 in human hyperplastic gastric polyps immunohistochemically. Twelve specimens of human hyperplastic gastric polyps were obtained from endoscopic polypectomy. The expression of the COX-2 protein was immunohistochemically examined on formalin-fixed and paraffin-embedded tissue sections using an anti-COX-2 antibody and an avidin-biotin complex method. Cells expressing COX-2 were further immunohistochemically identified using a specific antibody against macrophages (CD68), and myofibroblasts (alpha-smooth muscle actin). Immunoreactive COX-2 was predominantly and strongly expressed in interstitial cells in the sub-epithelial layer of 10 hyperplastic polyps. Semi-quantitative analysis revealed a significant increase in COX-2 expression in interstitial cells. The staining pattern of macrophages and myofibroblasts partly corresponded to that observed for COX-2 in hyperplastic gastric polyps. These results suggest that COX-2 in mesenchymal cells induced by H. pylori may play an important role in the tumorigenesis of human hyperplastic gastric polyps.
    Journal of experimental & clinical cancer research: CR 10/2003; 22(3):425-30. · 1.50 Impact Factor
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    ABSTRACT: Rebamipide (Reb) is an anti-ulcer drug, and has unique properties such as anti-inflammatory action. We previously reported that prostaglandins (PGs) dramatically increased vascular endothelial growth factor (VEGF), a known angiogenic factor and a vascular permeable factor, by activated macrophages through specific PGE receptor and peroxisome proliferator-activated receptor gamma (PPARgamma, a nuclear receptor of PG) mediated process. Effects of PGs on the production of other cytokines such as interleukin (IL)-6 and IL-8 have been controversial. To clarify the anti-inflammatory roles of Reb, we examined the effect of Reb on PGE1- and 15-deoxy-Delta12, 14-PGJ2 (a potent PPARgamma ligand, 15d-PGJ2) -induced increase of VEGF production by macrophages. Additionally, effects of these PGs on the production of IL-6 and IL-8, and modulation of these actions by Reb were studied. Phorbol 12-myristate 13-acetate-differentiated U937 cells were used as a human macrophage model (H-Mac). VEGF, IL-6, IL-8 and cAMP were measured by EIA. Reb suppressed PGE1-, but not 15d-PGJ2-, induced increase of VEGF production partially through decrease of cAMP formation. Reb suppressed PGE1 -, but not 15d-PGJ2-, induced increase of IL-6 and IL-8 production. Reb suppresses membrane, but not nuclear PG receptors mediated increase of inflammatory cytokine production, which may be involved in anti-ulcer action of this drug.
    Alimentary Pharmacology & Therapeutics 08/2003; 18 Suppl 1:113-8. · 4.55 Impact Factor
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    ABSTRACT: Wound-healing of the gastric mucosa is suggested to be stimulated by hepatocyte growth factor (HGF). Polyamines are shown to contribute to repair after damage in the gastric mucosa. The present study was designed to elucidate whether HGF can stimulate wound-healing of the gastric mucosa via polyamine production, using rabbit gastric mucosal cells in primary culture. A wound was made as a round cell-free area in the cell sheet of confluent cultured cells. When HGF was added to the culture medium, such denuded area was significantly reduced in size compared with the control, but the reduction was inhibited by addition of D,L-alpha-difluoromethylornithine (DFMO), an inhibitor of a rate-limiting enzyme (ornithine decarboxylase) of polyamine biosynthesis, to the culture medium. However, the inhibitory effect by DFMO was reversed by pretreatment with spermidine, but not with putrescine. Intracellular levels of polyamines in the whole confluent cells including the cells around the denuded area were not changed by addition of HGF, but putrescine and spermidine levels were decreased by further addition of DFMO. We conclude that spermidine may be involved in stimulation by HGF in the repair after damage of gastric mucosal cells.
    Biochimica et Biophysica Acta 02/2003; 1619(2):187-92. · 4.66 Impact Factor
  • Gastroenterology 01/2003; 124(4). · 12.82 Impact Factor

Publication Stats

2k Citations
606.69 Total Impact Points

Institutions

  • 2006
    • Japan Red Cross Fukuoka Hospital
      Hukuoka, Fukuoka, Japan
  • 1998–2006
    • Saitama Medical University
      • • Department of Pathology
      • • Department of Internal Medicine
      • • Saitama Medical Center
      Saitama, Saitama-ken, Japan
  • 2004
    • Massachusetts General Hospital
      • Department of Pathology
      Boston, MA, United States
  • 1994–1999
    • Dokkyo Medical University
      • Department of Gastroenterology (Hospital)
      Tochigi, Tochigi-ken, Japan
  • 1987–1999
    • The University of Tokyo
      • • Department of Internal Medicine
      • • Division of Internal Medicine
      • • Faculty & Graduate School of Medicine
      Tokyo, Tokyo-to, Japan
  • 1997
    • California State University, Long Beach
      Long Beach, California, United States
  • 1988–1997
    • Long Beach Memorial Medical Center
      Long Beach, California, United States
  • 1996
    • Dokkyo University
      Edo, Tōkyō, Japan
  • 1995
    • University of California, Irvine
      Irvine, California, United States