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Biomedical subjects

Yasuhiro Fujiwara

Publications and source records attributed to Yasuhiro Fujiwara.

At least 55 records · Page 3Linked to original sources
PubMed2005

Functional oesophageal epithelial defense against acid.

Functional oesophageal epithelial defense, including cell proliferation, restitution, buffers and ion transporters, plays a significant role in maintaining mucosal integrity and enabling rapid repair after injury. Growth factors such as epidermal growth factor (EGF), transforming growth factor-alpha (TGF-alpha), hepatocyte growth factor (HGF) and keratinocyte growth factor (KGF) are associated with oesophageal epithelial proliferation or restitution. Na+/H+ exchanger-1, an ion transporter, regulates intracellular pH and cell volume, and may have roles in cell proliferation, migration and survival. Cytokine, adhesion molecules, cyclooxygenase-2 and free radicals are associated with oesophageal inflammation and breach of the functional epithelial defense. Although the oesophagus does not have strong functional epithelial defense against acid, this defensive mechanisms may be involved in the pathogenesis of non-erosive gastro-oesophageal reflux disease. Medical therapy may be developed in future to enhance functional oesophageal epithelial defense.

Cell Proliferation↗
PubMed2005

Structure of new carotenoids with a 3,4-dihydroxy-beta-end group from the oyster Crassostrea gigas.

Three new carotenoids with a 3,4-dihydroxy-beta-end group were isolated from the oyster Crassostrea gigas. These structures were determined to be 3,4,3',8'-tetrahydroxy-beta,kappa-caroten-6'-one (1), 3,4-dihydroxy-3',6'-epoxy-1',2',5',6'7',8'-hexahydro-6'-methyl-16'-nor-beta,-carotene-1',8'-dione (2), and 3,6-epoxy-5,3',4'-trihydroxy-12',13',20'-trinor-beta,beta-caroten-19,11-olide (3) based on chemical and spectral data.

Animals↗
PubMed2005

Dislocation of tight junction proteins without F-actin disruption in inactive Crohn's disease.

Crohn's disease is associated with increased permeability of the intestinal barrier even in quiescent patients. Increased intestinal permeability may cause dysregulated immunological responses in the intestinal mucosa that leads to chronic intestinal inflammation. We have studied the expression of tight junction proteins (occludin and zonula occludens), alpha2-smooth muscle actin, TGF-beta with a cytoskeletal protein (F-actin) in the intestinal epithelium of patients with inflammatory bowel disease. Surgical samples were obtained from 6 controls (individuals without inflammatory bowel disease), 8 patients with ulcerative colitis and 7 patients with Crohn's disease. F-actin was visualized with fluorescein phalloidin. Tight junction proteins, alpha2 smooth muscle actin, and TGFbeta were visualized by the immunofluorescent method. Occludin and zonula occludens found in apical tight junctions in normal epithelium were dislocated to the basolateral position and in the lamina propria extracellular matrix in patients with Crohn's disease, while the structure of F-actin was maintained in inactive or minimally inflamed mucosa. TGF-beta positive inflammatory cells were increased in ulcerative colitis and Crohn's disease mucosa. Subepithelial myofibroblasts were constitutively found in controls, ulcerative colitis, and Crohn's disease mucosa. Latent dislocation of tight junction proteins, without disturbance of the cytoskeleton in the inactive mucosa of patients with Crohn's disease, may permit the invasion of gut antigens because the functional disruption of tight junctions could initiate an altered immune response.

Actins↗
PubMed2005

Significance of increased proliferation of immature plasma cells in the appendix of patients with ulcerative colitis.

The etiology of ulcerative colitis (UC) is not known. Recent studies support a primary role of the appendix in the pathogenesis of UC, however phenotypical studies of proliferating cells in the appendix have not been reported. We report phenotypical studies of lymphocytes and of proliferating subpopulations in the appendix of patients with inflammatory bowel disease and of controls. Surgical samples of the appendix were obtained from 5 patients with colon cancer, 5 with acute appendicitis, 12 with UC and 7 with Crohn's disease (CD). Frozen sections were cut from fixed samples, and immunostained with lymphocyte markers and anti-Ki-67 antibodies. The number of Ki-67(+) proliferating cells, CD19, and CD138 cells was significantly higher in the appendix of patients with UC than in controls, patients with acute appendicitis, and patients with CD. Immunohistological double staining revealed significant proliferation of CD3, CD19, and CD138 cells in the appendix of patients with UC. The proportions of Ki-67(+) cells in CD3, CD19, and CD138 cells were significantly higher in both total UC patients and patients in remission-stage UC, than in controls, patients with acute appendicitis, and patients with CD. Lamina propria cells in the appendix of patients with UC showed augmented proliferation with increased numbers of CD19 and CD138 cells. The number of CD3 cells was not significantly increased, but the proportion of proliferating CD3 cells was increased. An increased proportion of Ki-67(+) cells in CD19 and CD138 cells represents proliferation of immature plasma cells in the appendix of patients with UC, and proliferation of such immature plasma cells was seen in both active- and remission-stage UC. Proliferation of immature plasma cells in the appendix of patients with UC suggests a primary role of humoral immune responses in the pathogenesis of UC.

Adolescent↗
PubMed2005

Relationship between peroxisome proliferator-activated receptor-gamma expression and differentiation of human esophageal squamous cell carcinoma.

Peroxisome proliferator-activated receptor-gamma (PPAR-gamma), a member of the nuclear hormone receptor superfamily, is involved in suppressing the growth of several tumors. We showed that PPAR-gamma is expressed in Barrett's adenocarcinoma cell lines and inhibited the growth of these lines through the induction of G1 cell cycle arrest and apoptosis. We examined PPAR-gamma expression in human esophageal squamous cell carcinoma (SCC) in vitro and in vivo and investigated whether PPAR-gamma ligands affect the proliferation and apoptosis of human SCC cell lines. Biopsy specimens (n=46) obtained from human SCC of the esophagus were stained using a monoclonal antibody against human PPAR-gamma. We assessed the effects of PPAR-gamma ligands on the growth of SCC cells by adding 15-deoxy prostaglandin J2 (15d-PGJ2), or troglitazone to six human esophageal SCC cell lines (TE-1, TE-2, TE-3, TE-5, TE-8, and TE-9). Immunohistochemical staining showed that 34 of 46 (73.9%) SCC of the esophagus expressed PPAR-gamma. All SCC cell lines expressed PPAR-gamma mRNA and protein, especially when poorly differentiated (TE-2, TE-5, and TE-9). The PPAR-gamma ligands significantly and dose-dependently inhibited the proliferation of SCC lines, except for well-differentiated TE-1 and TE-3. Apoptosis was induced by 15d-PGJ2 (10 microM) in all tested SCC lines except TE-1, whereas troglitazone (50 microM) was marginally effective in only the TE-2 and TE-3 cell lines. The present findings suggest that PPAR-gamma could be a therapeutic target for treating squamous cell carcinoma of the esophagus, possibly through the induction of apoptosis.

Antibodies, Monoclonal↗
PubMed2004

Monocyte chemotactic protein-1 regulates leukocyte recruitment during gastric ulcer recurrence induced by tumor necrosis factor-alpha.

TNF-alpha has numerous biological activities, including the induction of chemokine expression, and is involved in many gastric injuries. C-C chemokines [monocyte chemotactic protein (MCP)-1 and macrophage inflammatory protein (MIP)-1alpha] and C-X-C chemokines [MIP-2 and cytokine-induced neutrophil chemoattractant (CINC)-2alpha] mediate chemotaxis of monocytes and neutrophils, respectively. We examined the roles of TNF-alpha and dynamics of chemokine expression in gastric ulceration including ulcer recurrence and indomethacin-induced injury. Rats with healed chronic gastric ulcers received intraperitoneal TNF-alpha to induce ulcer recurrence. Some rats were given neutralizing antibodies against neutrophils or MCP-1 together with TNF-alpha. In a separate experiment, rats were orally administered 20 mg/kg indomethacin with or without pretreatment with pentoxifylline (an inhibitor of TNF-alpha synthesis) or anti-MCP-1 antibody. TNF-alpha (1 microg/kg) induced gastric ulcer recurrence after 48 h, which was completely prevented by anti-neutrophil antibody. TNF-alpha increased the number of macrophages and MCP-1 mRNA expression in scarred mucosa from 4 h, whereas it increased MPO activities (marker of neutrophil infiltration) and mRNA expression of MIP-2 and CINC-2alpha from 24 h. Anti-MCP-1 antibody inhibited leukocyte infiltration with reduction of the levels of C-X-C chemokines and prevented ulcer recurrence. Indomethacin treatment increased TNF-alpha/chemokine mRNA expression from 30 min and induced macroscopic erosions after 4 h. Pentoxifylline inhibited the indomethacin-induced gastric injury with reduction of neutrophil infiltration and expression of chemokine (MCP-1, MIP-2, and CINC-2alpha). Anti-MCP-1 antibody also inhibited the injury and these inflammatory responses but did not affect TNF-alpha mRNA expression. In conclusion, increased MCP-1 triggered by TNF-alpha may play a key role in gastric ulceration by regulating leukocyte recruitment and chemokine expression.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed2004

Characterization of epoxy carotenoids by fast atom bombardment collision-induced dissociation MS/MS.

The characterization and structure of epoxy carotenoids possessing 5,6-epoxy, 5,8-epoxy and 3,6-epoxy end groups conjugated to the polyene chain were investigated using high-energy fast atom bombardment collision-induced dissociation MS/MS methods. In addition to [M - 80](+*), a characteristic fragment ion of an epoxy carotenoid, product ions resulting from the cleavage of C-C bonds in the polyene chain from the epoxy end group, such as m/z 181 (b ion) and 121 (c ion), were detected. On the other hand, diagnostic ions of m/z 286 (e-H ion) and 312 (f-H ion) were observed, not in the 5,6-epoxy or 5,8-epoxy carotenoid but in the 3,6-epoxy carotenoid. These fragmentation patterns can be used to distinguish 3,6-epoxy carotenoids from 5,6-epoxy or 5,8-epoxy carotenoids. The structure of an epoxy carotenoid, 3,6-epoxy-5,6-dihydro-7',8'-didehydro-beta,beta-carotene-5,3'-diol (8), isolated from oyster, was characterized using FAB CID-MS/MS by comparing fragmentation patterns with those of related known compounds.

Animals↗
PubMed2004

Expression of insulin-like growth factor 1 receptor in primary breast cancer: immunohistochemical analysis.

Insulin-like growth factor-1 receptor (IGF-1R) has been implicated in regulation in tumor growth. The results of previous studies performed by radioimmunoassay are conflicting, and the prognostic significance of IGF-1R expression in primary breast cancer is still controversial. IGF-1R expression was evaluated in formalin-fixed, paraffin-embedded tissue of 210 primary breast cancer patients by using anti-IGF-1R antibody. The clinicopathologic variables and 5-year disease-free survival were studied, and their correlations between IGF-1R expressions were investigated. IGF-1R overexpression was observed in 43.8% of tumors. IGF-1R overexpression had no correlation with prognosis or with other clinicopathologic parameters, such as age, tumor size, nodal status, histologic grade, hormone receptor status, and human epidermal growth factor 2 status. Though its prognostic value in breast cancer is limited, immunohistochemical evaluation of IGF-1R by using this monoclonal antibody may be useful in translational research using archived material.

Adenocarcinoma↗
PubMed2004

Increased expression of transforming growth factor-alpha and epidermal growth factor receptors in rat chronic reflux esophagitis.

BACKGROUND AND AIM: Transforming growth factor-alpha (TGF-alpha), which binds to epidermal growth factor receptors (EGF-R), stimulates esophageal epithelial cell proliferation, enabling rapid repair after mucosal injury. The aim of the present study was to examine epithelial proliferation and dynamics of TGF-alpha and EGF-R gene and protein expression in rat chronic acid reflux esophagitis. METHODS: Gastric acid reflux esophagitis was induced in Wistar rats by ligating the transitional region between the forestomach and the glandular portion, and by covering the duodenum near the pyloric ring with a small piece of an 18Fr Nélaton catheter. Epithelial cell proliferation was assessed by bromodeoxyuridine (BrdU) uptake. Expression of TGF-alpha and EGF-R mRNA and protein was assessed by reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry. RESULTS: Esophageal lesions were observed in the lower and middle esophagus. Histologically, a significant increase in mucosal thickening with elongation of lamina propria papillae and basal cell hyperplasia was observed. The BrdU labeling index was significantly increased from 2.7 +/- 1.0 in normal mucosa and 2.8 +/- 1.2 in background mucosa adjacent to the esophageal lesion, to 60.3 +/- 32.7 in the lesions of chronic esophagitis. Expression of TGF-alpha and EGF-R mRNA in the esophageal lesion significantly increased compared to those in the control and background tissue, whereas treatment with rabeprazole significantly inhibited increases in TGF-alpha and EGF-R mRNA expression. According to immunohistochemical study, TGF-alpha and EGF-R revealed strong expression in esophageal lesions compared with control and background mucosa. The superficial layer of the esophagus was strongly positive for TGF-alpha and most cells in regions of basal hyperplasia had a positive reaction for EGF-R in the esophagitis lesion. CONCLUSION: Epithelial proliferation and expression of TGF-alpha and EGF-R were significantly increased in rat chronic reflux esophagitis. Activation of TGF-alpha and EGF-R genes in response to acid reflux may facilitate rapid mucosal healing by stimulating epithelial proliferation. These results suggest that TGF-alpha and EGF-R play crucial roles in rat chronic reflux esophagitis.

Amino Acid Sequence↗
PubMed2004

Safety and efficacy of S-1, a novel oral fluorouracil antitumor drug, for a chronic renal failure patient maintained on hemodialysis.

OBJECTIVE: S-1 is a novel oral fluorouracil antitumor drug that combines three pharmacological agents: tegafur (FT), a prodrug of 5-fluorouracil (5-FU); 5-chloro-2,4-dihydroxypyridine (CDHP), an inhibitor of dihydropyrimidine dehydrogenase, and potassium oxonate (Oxo), a reducer of gastrointestinal toxicity. S-1 has safe and potent antitumor effects in patients with gastric cancer via these respective functions. However, the plasma 5-FU concentration is suspected to accumulate in patients with renal dysfunction, because 50% of the CDHP is excreted into the urine. There are no useful data on safety and efficacy of S-1 in chronic renal failure patients maintained on hemodialysis (HD). We examined the influence of HD on the pharmacokinetics (PK) of S-1 and its therapeutic efficacy in liver metastases from gastric cancer. METHODS: For the HD patient, the dose of S-1 in a single-administration study was set at 50 mg/body/day (41.7% of the recommended dose of 80 mg/m2/day). S-1 was given to the patient 24 h after HD. Blood samples were obtained before administration and 2, 4, 6, 8, and 24 h thereafter and 1, 2, 4, and 72 h after the following HD session. The PK parameters (5-FU, CDHP, Oxo, and FT) were measured, and Cmax, Tmax, AUC0-24, and T1/2 were calculated. The dose of consecutive or maintained administrations was determined. RESULTS: Both an increase in Cmax and an elongation of T1/2 for 5-FU, CDHP, and Oxo, but not for FT, occurred in this case as compared with controls. The AUC0-24 of 5-FU in this case was similar to that of controls at the standard dose. After HD, 87.8, 54.5, 77.4, and 66.2% of 5-FU, CDHP, Oxo, and FT, respectively, were eliminated. A slight accumulation of CDHP did not alter the 5-FU PK. Consecutive or maintained S-1 oral administration at the same dose showed similar effects on all PK parameters of a single-administration test. Liver metastases almost totally regressed with no adverse events 4 weeks after S-1 treatment (50 mg/body/day three times a week). CONCLUSION: Adjusted doses of S-1 according to the results of PK studies may provide therapeutic safety and high efficacy in liver metastases from gastric cancer, even in chronic renal failure patients maintained on HD.

Administration, Oral↗
PubMed2004

Has Helicobacter pylori eradication for peptic ulcer been overrated?

Discovery of Helicobacter pylori has changed the life cycle of peptic ulcer disease (PUD). However, PUD does not completely disappear after elimination of H. pylori. Some ulcers recur even after successful eradication of H. pylori in non-users of non-steroidal anti-inflammatory drug (NSAID). In addition, the incidence of H. pylori-negative, non-NSAID PUD (idiopathic PUD) is reported to increase with time. Moreover, H. pylori-positive ulcers are not always H. pylori-induced ulcers because there are two paradoxes of the H. pylori myth: the existence of H. pylori-positive non-recurring ulcer and recurring ulcer after cure of H. pylori infection. Taken together, H. pylori is not the only cause of peptic ulcer disease. Therefore, it is still necessary to seriously consider the pathophysiology and the management of the ulcers, which may exist after elimination of H. pylori.

Causality↗
PubMed2004

[Peptic ulcer recurrence after successful eradication of Helicobacter pylori--clinical characteristics and management].

Peptic ulcer recurrence after successful eradication of Helicobacter pylori(H. pylori) is not rare. We evaluated the effect of H. pylori eradication on prevention of gastric ulcer recurrence. Ulcer recurrence had occurred in 20 of 256 H. pylori-eradicated patients, and most of ulcer recurrence were found within 1 year after eradication. NSAIDs and psychological stress, but not sex, smoking habit, drinking habit, and past history of ulcer, seem to be associated with ulcer recurrence. Intractable ulcers after the eradication of H. pylori frequently recurred. Some recurrent ulcers were refractory to treatment with H2-receptor antagonists or proton pump inhibitors. The mechanism(s) by which healed ulcers recur after successful eradication of H. pylori remains unclear.

Helicobacter Infections↗
PubMed2004

[Pathogenesis and treatment of refractory gastroesophageal reflux disease in Japanese patients].

Prevalence of refractory gastroesophageal reflux disease (GERD) defined as a patient who have persistent GERD symptoms during treatment with proton pump inhibitor (PPI) is rare in Japanese patinets. Pathogenesis of refractory GERD is associated with several factors including dysfunction of esophageal motility, presence of severe hiatal hernia, complication such as stricture and short esophagus, extensive metabolizer of CYP2C19 genotype, nocturnal gastric acid breakthrough, absence of H. pylori infection, or bile reflux. Examination by 24 hr pH monitoring is necessary to assess refractory GERD and if acid suppression is insufficient, treatment with double doses of PPIs or combination of PPI and H2 blocker is effective. However, most cases of refractory GERD are required surgical treatment. Endoscopic therapy might be useful for refractory GERD in future.

Aryl Hydrocarbon Hydroxylases↗
PubMed2003

Increased expression of cytokines and adhesion molecules in rat chronic esophagitis.

BACKGROUND/AIMS: Cytokines and adhesion molecules regulate many inflammatory processes in several gastrointestinal diseases. The dynamics of cytokines and adhesion molecules in reflux esophagitis are unknown in detail. We examined the expression and dynamics of interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha), monocyte chemotactic protein-1 (MCP-1), macrophage inflammatory protein-1alpha (MIP-1alpha), MIP-2, GRO/cytokine-induced neutrophil chemoattractant-2alpha (CINC-2alpha), intercellular adhesion molecule-1 (ICAM-1), leukocyte function-associated antigen 1 (LFA-1; CD11a/CD18), and Mac-1 (CD11b/CD18) in rat chronic reflux esophagitis. METHODS: Chronic acid reflux esophagitis was induced in Wistar rats by ligating the transitional region between the forestomach and the glandular portion and wrapping the duodenum near the pylorus with a small piece of an 18-Fr Nélaton catheter. Rats were killed 3 or 21 days after operation. The levels of mRNA expression of cytokines and ICAM-1 were determined by real-time quantitative RT-PCR. Localization of adhesion molecules and cytokines was investigated by immunohistochemical staining, and numbers of LFA-1- or Mac-1-positive cells were quantified. RESULTS: IL-1beta, TNF-alpha, MCP-1, MIP-1alpha, MIP-2, CINC-2alpha, and ICAM-1 mRNA expression was significantly increased in esophageal lesions compared with normal esophagus. There were few these cytokines- or adhesion molecule-positive cells in normal esophagus. In regions of esophagitis, numerous inflammatory leukocytes in lamina propria and the submucosal layer exhibited positive reactions for these cytokines and endothelial cells were intensely stained for ICAM-1. Numbers of LFA-1- and Mac-1-positive cells were significantly increased in rat chronic esophagitis. Treatment with rabeprazole almost completely inhibited development of chronic acid reflux esophagitis and significantly decreased expression of cytokines and ICAM-1 mRNA in esophageal tissue compared with control. CONCLUSION: Cytokines and adhesion molecules play important roles in the pathogenesis of chronic reflux esophagitis in this rat model.

Animals↗
PubMed2003

Anti-inflammatory effect of two isoforms of COX in H. pylori-induced gastritis in mice: possible involvement of PGE2.

Neutrophil infiltration mediated by TNF-alpha is associated with various types of gastric injury, whereas PGs play a crucial role in gastric defense. We examined roles of two isoforms of cyclooxygenase (COX) and PGE2 in Helicobacter pylori-induced gastritis in mice. Mice infected with H. pylori were given selective COX-1 inhibitor SC-560 (10 mg/kg), selective COX-2 inhibitor NS-398 (10 mg/kg), or nonselective COX inhibitor indomethacin (2 mg/kg) with or without 16,16-dimethyl PGE2 for 1 wk. H. pylori infection increased levels of mRNA for COX-1 and -2 in gastric tissue by 1.2-fold and 3.3-fold, respectively, accompanied by a significant increase in PGE2 production by gastric tissue. H. pylori infection significantly elevated MPO activity, a marker of neutrophil infiltration, and epithelial cell apoptosis in the stomach. SC-560 augmented MPO activity and epithelial cell apoptosis with associated reduction in PGE2 production, whereas NS-398 had the same effects without affecting PGE2 production. Inhibition of both COX-1 and -2 by indomethacin or concurrent treatment with SC-560 and NS-398 resulted in a stronger increase in MPO activity and apoptosis than inhibition of either COX-1 or -2 alone. H. pylori infection elevated TNF-alpha mRNA expression in the stomach, which was further increased by indomethacin. Effects of COX inhibitors on neutrophil infiltration, apoptosis, and TNF-alpha expression in H. pylori-infected mice were abolished by exogenous 16,16-dimethyl PGE2. In conclusion, PGE2 derived from either COX-1 or -2 is involved in regulation of gastric mucosal inflammation and contributes to maintenance of mucosal integrity during H. pylori infection via inhibition of TNF-alpha expression.

Animals↗