T Hayakawa

Aichi Medical University, Okazaki, Aichi, Japan

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Publications (512)1100.69 Total impact

  • ChemInform 01/2010; 25(45).
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    ABSTRACT: Despite advances in endoscopic procedures and extracorporeal shock wave lithotripsy (ESWL), the removal of impacted pancreatic duct stones demands a certain amount of time. The aim of this study was to determine which patient group might suitable for our single-session treatment. The study included 17 patients who were symptomatic due to relapsing pancreatitis with pancreatic duct stones. A 5-Fr miniscope was inserted via the papilla to the impacted pancreatic duct stone and pancreatoscopic laser lithotripsy (PSLL) was performed, under direct vision, in only one session. If complete extraction of the pancreatic duct stones was not achieved with PSLL, ESWL was adopted in subsequent sessions. Complete extraction of the pancreatic duct stones using PSLL in a single session was achieved in eight of 17 patients. Single-session PSLL was only suitable for patients with pancreatic duct stones smaller than 17 mm in diameter and with no severe stricture or sharp bend in the pancreatic duct proximal to the stones. Our single-session endoscopic treatment of pancreatic duct stones was useful in a selected patient group.
    Endoscopy 04/2004; 36(3):212-6. · 5.74 Impact Factor
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    ABSTRACT: Antral somatostatin interacts with gastric acid secretion. We aimed to investigate the effect of eradication on gastric acid, somatostatin secretion and mucosal histology in gastric ulcer patients with Helicobacter pylori (H. pylori) infection. Twenty-eight patients (21 male, 7 female) with H. pylori-positive gastric ulcer were treated with dual therapy. Before and 4-8 weeks after the therapy, the histology of biopsy specimens, basal acid output (BAO) and maximal acid output (MAO) after stimulation with tetragastrin were assessed. Somatostatin concentration in the gastric juice was measured by radioimmunoassay, and somatostatin output during either the basal or gastrin-stimulated period was also examined. Eradication was successful in 22 patients. Before treatment, the acid and somatostatin output were inversely related to the severity of neutrophil infiltration in the corpus and antrum, respectively. After successful eradication, improvement of histological inflammation and an increase in BAO, basal and gastrin-stimulated somatostatin output were observed. Eradication had no effect on atrophy and MAO. There was a positive correlation between gastric acid and somatostatin output in the basal or stimulated condition, irrespective of H. pylori infection. The present results suggest that recovery of gastric BAO may be caused by an improvement in corpus neutrophil infiltration, but not by an increase in parietal cell volume or a change in atrophy. Also, there was an increase in basal and gastrin-stimulated somatostatin-containing cell activity accompanied by improved antral neutrophil infiltration in the early phase after H. pylori eradication in gastric ulcers.
    Journal of Gastroenterology and Hepatology 06/2003; 18(5):505-11. · 3.33 Impact Factor
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    ABSTRACT: Although endoscopic ultrasonography is considered the most useful diagnostic modality for the regional staging, the capability of diagnosing lymph node metastasis based on endoscopic ultrasonography images alone is not sufficient. To improve the capability of differential diagnosis of lymph node enlargement, contrast-enhanced echolymphography was performed using endoscopic ultrasonography-guided puncture. Contrast-enhanced echolymphography was performed in 8 metastatic lymph nodes surgically resected from patients with gastrointestinal cancers (in vitro study) and also in 55 patients in whom abdominal lymph node swelling was indicated by endoscopic ultrasonography (in vivo study). Lymph nodes were punctured under real-time endoscopic ultrasonography guidance, and carbon dioxide microbubbles were injected to evaluate echo features before and after microbubbles injection. Contrast-enhanced echolymphography of freshly resected metastatic lymph nodes showed nonhomogeneous echo patterns. In regions demonstrating filling defects detected by contrast-enhanced echolymphography, neoplastic infiltration was pathologically observed. In almost all of the malignant lymph nodes studied in vivo, filling defects and heterogeneous enhancements were observed by contrast-enhanced echolymphography. However, contrast-enhanced echolymphography demonstrated uniform patterns in most of the benign group. The sensitivity, specificity, positive and negative predictive value, and accuracy of differential diagnosis by contrast-enhanced echolymphography were 95.8%, 90.3%, 88.5%, 96.6%, and 92.7%, respectively. Contrast-enhanced echolymphography is a useful method for help in the differentiation between reactive and malignant alterations of lymph nodes.
    Hepato-gastroenterology 01/2003; 50(53):1285-91. · 0.77 Impact Factor
  • Gastroenterology 01/2003; 124(4). · 12.82 Impact Factor
  • Gastroenterology 01/2003; 124(4). · 12.82 Impact Factor
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    ABSTRACT: Background. To investigate whether Helicobacter pylori infection, but not drugs, affects gastric somatostatin, interleukin-8 (IL-8), histological inflammation through eradication therapy, and interactions among these parameters.Methods. Twenty-eight H. pylori-positive patients (21 males; mean age 47.0 years) with either gastric ulcer (GU: n = 11) or duodenal ulcer (n = 17) diagnosed endoscopically were treated with dual therapy. Eradication was defined as negative microbiologic tests and 13C-urea breath test. Levels of antral and gastric juice somatostatin and mucosal IL-8 were measured by radioimmunoassay and enzyme-linked immunosorbent assay, respectively. Histology was assessed by the Sydney system.Results. H. pylori was eradicated in 15 patients (10 males, 6 GU) out of 28 (54%). The patients’ backgrounds did not affect the eradication of H. pylori. Successes in eradication significantly increased antral and juice somatostatin contents, and dramatically decreased IL-8 levels and histological gastritis. In contrast, persistent H. pylori infection did not affect somatostatin and histological gastritis. An inverse correlation was present between changes in somatostatin levels and histological activity. No relationship was observed in changed values between antral somatostatin and IL-8.Conclusions.  These results indicate that eradication of H. pylori, but not the drugs used, induced an increase in somatostatin levels in the antrum and gastric juice, suggesting a close relationship between H. pylori and gastric somatostatin regulation. A close correlation between an increase in gastric somatostatin levels and the normalization of histological activity was present, suggesting that certain peptide-immune interactions in the gastric mucosa exist in H. pylori infection.
    Helicobacter 12/2001; 6(2):136 - 145. · 3.51 Impact Factor
  • Gastroenterology 01/2001; 120(5). · 12.82 Impact Factor
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    ABSTRACT: At present developed modalities are not sufficient for detecting early stage pancreatic cancer. We previously reported the clinical usefulness of intraductal ultrasonography in various pancreatobiliary diseases. In the present study we assessed the usefulness of intraductal ultrasonography in diagnosing pancreatic cancer. Thirty-one patients with pancreatic cancer were examined by intraductal ultrasonography. We approached the main pancreatic duct (pancreatic duct-intraductal ultrasonography) in 24 of 31 patients and the bile duct (bile duct-intraductal ultrasonography) in 20 patients with pancreatic cancer. We compared the diagnostic ability of pancreatic duct-intraductal ultrasonography with that of extracorporeal ultrasonography, computed tomography, endoscopic ultrasonography or endoscopic retrograde pancreatography. We examined the usefulness of bile duct-intraductal ultrasonography in diagnosing tumor invasion to the bile duct. Pancreatic duct-intraductal ultrasonography was able to demonstrate a tumor in 22 of 24 patients. Extracorporeal ultrasonography, computed tomography, endoscopic ultrasonography or endoscopic retrograde pancreatography detected tumors in 26, 27, 29, 29 of 31 patients, respectively. In two patients, only intraductal ultrasonography could demonstrate a tumor, which was not detected by any other modalities. We examined bile duct invasion of the tumor according to our grading system. The overall accuracy rate was 90%. No complications were noted in any patients throughout the study period. Intraductal ultrasonography is useful to diagnose pancreatic cancer, and it is suggested that it should be actively performed after endoscopic retrograde pancreatography.
    Hepato-gastroenterology 01/2001; 48(40):928-32. · 0.77 Impact Factor
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    ABSTRACT: The spontaneous disappearance and reappearance of a ruptured cerebral aneurysm is generally assumed to be a rare phenomenon although the actual incidence is unknown. Among 39 consecutive cases of acute subarachnoid hemorrhage (SAH), 33 were studied by three-dimensional computed tomographic angiography (CTA) within 6 h after the onset of SAH, followed by digital subtraction angiography (DSA) within 24 h after the ictus. Of those patients, one, a 58-year-old woman, had a saccular aneurysm at the distal anterior cerebral artery; the aneurysm was clearly demonstrated by CTA 2.5 h after the SAH onset, but was not shown by a subsequent DSA performed 8.5 h after the ictus. A follow-up DSA detected the neck of aneurysm on day 11, and the whole aneurysm was visualized on day 19. The observations in this particular case suggest that the spontaneous disappearance of a ruptured cerebral aneurysm may occur during the ultra-early stage of SAH and that reappearance may follow during the next few weeks. The patient did not suffer complications such as vasospasm or systemic hypotension nor was she treated with antifibrinolytic agents. The aneurysmal shape and the surrounding clot are considered as putative factors possibly related to the intermittent appearance of the aneurysm.
    Neurological Research 10/2000; 22(6):583-7. · 1.18 Impact Factor
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    ABSTRACT: Polymorphonuclear neutrophil elastase is a neutral protease released by activated polymorphonuclear neutrophils and plays a crucial role in maintaining host defense. However, under certain conditions, this enzyme damages normal tissue and facilitates infiltration of tumor cells. In this study, surgical specimens were obtained from the tumor core and infiltrating margin of the glioma of 12 patients with astrocytoma of varying degrees of malignancy, and the specimens were tested for the presence of elastase by immunohistochemical analysis. Polymorphonuclear neutrophil elastase was not present in the tumor core of any of the 12 cases. Elastase was expressed in areas of tumor infiltration of the brain in all four glioblastoma cases, three of the four anaplastic astrocytoma cases, and none of the four low-grade astrocytoma cases. There was a higher percentage of elastase-positive polymorphonuclear neutrophils in the infiltrating margin of tumors with greater degree of malignancy. Polymorphonuclear neutrophils are recruited to malignant gliomas, and the elastase released by these cells aids in the infiltration of gliomas.
    Neurological Research 08/2000; 22(5):465-8. · 1.18 Impact Factor
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    ABSTRACT: For pretherapeutic staging of squamous cell carcinoma of the oesophagus, endoscopic ultrasonography (EUS) is considered the most profitable modality because it can provide cross sectional imaging of the tumour. The aim of this study was to evaluate the relation between prognosis and EUS findings, especially tumour area, in squamous cell carcinoma of the oesophagus. A total of 113 patients with squamous cell carcinoma of the oesophagus underwent EUS for pretherapeutic examination at Nagoya University Hospital. We compared EUS findings, histological results, and outcome. In addition, we measured the area of the tumour on EUS images (n=113) and evaluated if EUS area correlated with volume of the tumour on histological findings (n=50). The overall accuracy rate of EUS was 83.2% (94/113) for depth of tumour invasion and 67.6% (69/102) for perioesophageal lymph node metastasis. The EUS area increased in proportion to the development of tumour infiltration, and patients with lymph node metastasis had a larger EUS area than patients without lymph node metastasis. There was a close correlation between EUS area and volume of the tumour on histological findings. If EUS area of the tumour was less than 50 mm(2), the five year survival rate was 100%. As EUS area increased, the survival rate decreased. Measurement of EUS area of the tumour is reliable for quantification of the tumour and prediction of prognosis in patients with squamous cell carcinoma of the oesophagus.
    Gut 08/2000; 47(1):120-5. · 10.73 Impact Factor
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    ABSTRACT: Endoscopic biopsy is routine in gastrointestinal disease; similarly, histopathologic diagnosis is desirable in gallbladder disease. In this study we examined the clinical usefulness and the problems associated with transpapillary gallbladder biopsy. Transpapillary gallbladder biopsy was attempted in 9 patients with gallbladder disease. After inserting a catheter sheath into the gallbladder using a guidewire via the transpapillary route without sphincterotomy, we inserted a biopsy forceps into the lumen of the sheath up to the gallbladder lumen and obtained specimens. We could obtain sufficient specimens for histopathologic diagnosis in 8 of 9 cases (88.9%). Of the 8 successful cases, targeted specimens were obtained in 7 (87.5%). Diagnostic accuracy with respect to malignant versus benign disease was 100% (2 of 2) and 83.3% (5 of 6), respectively. There were no complications. Transpapillary gallbladder biopsy is a clinically useful technique because it facilitates histopathologic diagnosis and therefore guides the choice of therapy.
    Gastrointestinal Endoscopy 02/2000; 51(1):76-9. · 5.21 Impact Factor
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    ABSTRACT: N-acetylaspartate (NAA) is a plausible marker of neuronal viability which decreases in a variety of neurodestructive conditions. To elucidate the mechanism that leads to NAA decline in two different types of cerebral ischemia in rats, we simultaneously determined cortical concentrations of NAA and its hydrolytic metabolites, aspartate, and acetate by high-resolution 1H-NMR spectroscopy. NAA decreased almost linearly up to 24 h in both decapitation induced global cerebral ischemia, and in ischemic cortices of focal ischemia. Acetate was increased continuously for up to 24 h of global ischemia, while in focal cerebral ischemia it was increased transiently at 6 h. Aspartate did not show any change in global ischemia, while it was decreased in focal ischemia. Although NAA decreased similarly in the brain with global and focal ischemia, temporal changes of two NAA hydrolytic metabolites were different in each type of ischemia. The present results suggest hydrolytic degradation of NAA may be modified alternatively under each pathophysiologic condition.
    Neurological Research 01/2000; 21(8):771-4. · 1.18 Impact Factor
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    ABSTRACT: We investigated the effect of BDNF mini-pellet on the GAP-43 mRNA expression and functional status of facial nerve in a rat model of facial nerve transection and immediate repair. The facial function started to recover at 17 days in the placebo group and 14 days in the BDNF group. BDNF group had shorter period of increased GAP-43 mRNA expression than the placebo group. Topically applied BDNF may accelerate the facial nerve regeneration.
    Brain Research 01/2000; 849(1-2):235-8. · 2.88 Impact Factor
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    ABSTRACT: Tissue plasminogen activator (tPA) has been used to treat acute thrombotic lesions. Roles other than the activation of fibrinolytic pathways have been suggested for tPA in the mature brain. We used the in situ hybridization technique to investigate the changes in tPA mRNA expression within the brain after cortical ablation. We found that expression of tPA mRNA started to increase diffusely in the cortex ipsilateral to the injury 6 h after ablation. This increase had become prominent 24 h after ablation. On d 5, the expression of tPA mRNA had returned to that of the control animals except for the area near the injury. We also found that administration of MK-801 before injury suppressed the increase of tPA mRNA in the ipsilateral cortex. These results suggest that the increase in tPA mRNA is likely to be mediated via activation of NMDA receptors.
    Journal of Molecular Neuroscience 01/2000; 14(1-2):53-9. · 2.89 Impact Factor
  • Regulatory Peptides - REGUL PEPTIDES. 01/2000; 94(1):19-19.
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    ABSTRACT: We evaluated the usefulness of contrast-enhanced endoscopic ultrasonography (EUS) in the diagnosis of upper gastrointestinal (GI) tract diseases. The subjects were 42 patients with upper GI tract diseases: 4 esophageal carcinomas, 30 gastric carcinomas, 5 gastric myogenic tumors, and 3 gastric ulcers. After the lesion was observed by EUS, air-filled albumin (0.22 mL/kg) was intravenously injected at a rate of 1 mL/sec into the right cubital median vein, and observation was continued for 10 minutes. Enhancement of the third and fifth layers was observed in all normal esophageal and gastric walls. No esophageal carcinomas were enhanced. Enhancement was observed in 5 gastric carcinomas that had abundant, enlarged, and winding vascular beds. In all esophageal and the other 25 gastric carcinomas, although the tumors per se were not enhanced, enhancement of the third and fifth layers around the lesions clearly demarcated the tumor boundaries. As a result, accuracy for detection of the depth of gastric carcinoma improved from 76.7% for EUS to 90% for contrast-enhanced EUS. All gastric myogenic tumors were enhanced, and irregularly shaped sonolucent areas within these tumors became clear, but we could not distinguish between leiomyoma and leiomyosarcoma. Contrast-enhanced EUS is a noninvasive, useful diagnostic method for assessment of the depth of invasion of esophageal and gastric carcinomas.
    Gastrointestinal Endoscopy 11/1999; 50(4):555-60. · 5.21 Impact Factor
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    ABSTRACT: To clarify the usefulness of endoscopic ultrasonography (EUS) and endoscopy in the endoscopic mucosal resection (EMR) of early gastric cancer. Patients/Methods-EMR was performed in 61 patients with early gastric cancer over the past five years. The accuracy of the assessment of the depth of cancerous invasion was studied in 49 patients who had EUS before EMR. Forty eight patients were treated with endoscopy alone; in these patients, EUS and endoscopic findings correlated with the clinical course. Forty six patients showed no changes in the submucosal layer or deeper structures on EUS. Pathologically these included 37 patients with mucosal cancer and nine with submucosal cancer showing very slight submucosal infiltration. Three patients showed diffuse low echo changes in the submucosal layer on EUS; pathologically, these included two with submucosal cancer and one with mucosal cancer with a peptic ulcer scar within the tumour focus. Of 48 patients receiving endoscopic treatment alone, 45 showed no tumour recurrence or evidence of metastases on EUS and endoscopy. Three cases of recurrence were observed. Two of these patients had a surgical gastrectomy, and one was re-treated endoscopically. In the former cases, the surgical results correlated well with assessment by EUS and endoscopy. In addition, the latter patient who was re-treated endoscopically after evaluation with EUS and endoscopy has so far had no recurrence. The combined use of EUS and endoscopy is effective in diagnosing the depth of cancerous invasion in patients undergoing EMR as well as in clarifying changes both within and between anatomic levels during follow up.
    Gut 11/1999; 45(4):599-604. · 10.73 Impact Factor
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    ABSTRACT: We investigated the role of the I-E-N-K-L (amino acids 1057-1061) sequence amino-terminal to Tyr1062 in Ret for binding of the Shc phosphotyrosine-binding (PTB) domain. Substitution of Ser for Ile1057 (I1057S), Ala for Asn1059 (N1059A), or Pro for Leu1061 (L1061P) in this sequence significantly decreased the transforming activity of Ret with the multiple endocrine neoplasm type 2A (MEN2A) mutation as well as the binding affinity of Shc to it in vivo and in vitro, indicating that these three amino acids play a role in Shc binding. In addition, as the RET protooncogene is translated as three isoforms of 1114 amino acids (Ret 51), 1106 amino acids (Ret 43), and 1072 amino acids (Ret 9) that differ from one another in the sequence carboxyl-terminal to Tyr1062, we examined whether these sequence differences influence the binding affinity of Shc to Ret. As a result, we found that the transforming activity of Ret 43 isoform with the MEN2A mutation and the binding affinity of Shc to it were very low, although the consensus sequence for the binding of the Shc PTB domain is conserved in the Ret 43 isoform. This finding suggested that the sequence carboxyl-terminal to Tyr1062 in Ret could also influence the binding affinity to Shc.
    Endocrinology 10/1999; 140(9):3992-8. · 4.72 Impact Factor

Publication Stats

4k Citations
1,100.69 Total Impact Points


  • 2001–2003
    • Aichi Medical University
      • Division of Internal Medicine
      Okazaki, Aichi, Japan
  • 1987–2000
    • Osaka City University
      • Department of Neurosurgery
      Ōsaka-shi, Osaka-fu, Japan
  • 1999
    • Kagoshima University
      • Department of Neurosurgery
      Kagoshima-shi, Kagoshima-ken, Japan
    • Sapporo City General Hospital
      Sapporo, Hokkaidō, Japan
    • Toyohashi Municipal Hospital
      Toyohasi, Aichi, Japan
  • 1997–1999
    • Aichi Cancer Center
      Ōsaka, Ōsaka, Japan
  • 1992–1999
    • Toyonaka Municipal Hospital
      Toyonaka, Ōsaka, Japan
  • 1985–1999
    • Osaka University
      • • Division of Neurosurgery
      • • School of Medicine
      Ōsaka-shi, Osaka-fu, Japan
  • 1998
    • Osaka Prefecture Senshu Critical Care Medical Center
      Ōsaka, Ōsaka, Japan
  • 1996–1998
    • Osaka Medical Center for Cancer and Cardiovascular Diseases
      Ōsaka, Ōsaka, Japan
    • Japan Research Institute
      Ōsaka, Ōsaka, Japan
  • 1991–1998
    • Osaka Medical Center and Research Institute for Maternal and Child Health
      Izumi, Ōsaka, Japan
  • 1995–1997
    • Nagoya University
      • Division of of Internal Medicine
      Nagoya-shi, Aichi-ken, Japan
    • Nagoya Second Red Cross Hospital
      Nagoya, Aichi, Japan
  • 1994–1997
    • The Graduate University for Advanced Studies
      Миура, Kanagawa, Japan
  • 1987–1996
    • Osaka National Hospital
      Ōsaka, Ōsaka, Japan
  • 1993–1995
    • Osaka University of Health and Sport Sciences
      • Faculty of Health and Sport Sciences
      Toyonaka, Ōsaka, Japan
  • 1991–1995
    • Kinki University
      • Department of Neurosurgery
      Ōsaka, Ōsaka, Japan
  • 1988–1995
    • Osaka Rosai Hospital
      Ōsaka, Ōsaka, Japan
    • Kansai Rosai Hospital
      Itan, Hyōgo, Japan