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Biomedical subjects

Hiroto Kita

Publications and source records attributed to Hiroto Kita.

At least 19 recordsLinked to original sources
PubMed2005

Non-steroidal anti-inflammatory drug-induced small bowel injuries identified by double-balloon endoscopy.

AIM: To clarify clinical features of the NSAID-induced small bowel lesions using a new method of endoscopy. METHODS: This is a retrospective study and we analyzed seven patients with small bowel lesions while taking NSAIDs among 61 patients who had undergone double-balloon endoscopy because of gastro-intestinal bleeding or anemia between September 2000 and March 2004, at Jichi Medical School Hospital in Japan. Neither conventional EGD nor colonoscopy revealed any lesions of potential bleeding sources including ulcerations. Double-balloon endoscopy was carried out from oral approach in three patients, from anal approach in three patients, and from both approaches in one patient. RESULTS: Ulcers or erosions were observed in the ileum in six patients and in the jejunum in one patient, respectively. The ulcers were multiple in all the patients with different features from tiny punched out ulcers to deep ulcerations with oozing hemorrhage or scar. All the patients recovered uneventfully and had full resolution of symptoms after suspension of the drug. CONCLUSION: NSAIDs can induce injuries in the small bowel even in patients without any lesions in both the stomach and colon.

Administration, Oral↗
PubMed2005

A case of esophageal stricture due to metastatic breast cancer diagnosed by endoscopic mucosal resection.

Metastasis of breast cancer to the esophagus has been reported but is rare. It is often difficult to diagnose metastases of breast cancer to the esophagus because they are often located in the submucosa and covered with normal mucosa. Although several methods have been reported in order to obtain specimens for pathological diagnosis, the adverse effects including bleeding and perforation were considerable problems. We report a case of a patient with esophageal stricture due to metastatic breast cancer to the esophagus. Pathological diagnosis was successfully obtained using endoscopic mucosal resection of the esophagus.

Adenocarcinoma↗
PubMed2005

Clinical outcomes of enteroscopy using the double-balloon method for strictures of the small intestine.

AIM: To evaluate the clinical outcome of enteroscopy, using the double-balloon method, focusing on the involvement of neoplasms in strictures of the small intestine. METHODS: Enteroscopy, using the double-balloon method, was performed between December 1999 and December 2002 at Jichi Medical School Hospital, Japan and strictures of the small intestine were found in 17 out of 62 patients. These 17 consecutive patients were subjected to analysis. RESULTS: The double-balloon enteroscopy contributed to the diagnosis of small intestinal neoplasms found in 3 out of 17 patients by direct observation of the strictures as well as biopsy sampling. Surgical procedures were chosen for these three patients, while balloon dilation was chosen for the strictures in four patients diagnosed with inflammation without involvement of neoplasm. CONCLUSION: Double-balloon enteroscopy is a useful method for the diagnosis and treatment of strictures in the small bowel.

Adult↗
PubMed2005

Enteroscopy.

Wireless capsule endoscopy and double-balloon endoscopy are new methods of enteroscopy that have been introduced in recent years. Wireless capsule endoscopy is an epoch-making examination method that makes possible an endoscopic imaging examination of the entire small intestine without discomfort and without confining patients to a medical facility. Although it is expected to be useful as an initial examination for finding diseases of the small intestine, it cannot be used for biopsy or treatment. One risk associated with the capsule endoscopy technique is entrapment by strictures. Double-balloon endoscopy is based on a new insertion technique in which two balloons, one at the distal end of the endoscope and the other at the distal end of an overtube, are operated in combination, and the endoscope is inserted while simultaneously shortening the intestine. It can be inserted through either the mouth or the anus, allowing the observation of the entire gastrointestinal tract. It features excellent maneuverability even in the distal small intestine, and enables back-and-forth observation, biopsy, and endoscopic treatment at any given site. These two new enteroscopy techniques are expected to lead to innovations in how diseases of the small intestine are approached.

Endoscopes, Gastrointestinal↗
PubMed2005

Endoscopic therapy of early gastric cancer.

Endoscopic therapy of early gastric cancer is applicable for differentiated-type mucosal carcinomas that have an extremely low potency of lymph-node metastasis. Among various kinds of endoscopic therapy, endoscopic mucosal resection is the most recommended procedure, because pathological evaluation of affected tissues is available using this method. Recently, endoscopic submucosal dissection, a novel method of endoscopic mucosal resection, has gained interest as a more reliable therapeutic procedure. In the present chapter several issues will be presented on endoscopic therapy for early gastric cancer, including endoscopic diagnosis of early gastric cancer, currently accepted indications of endoscopic therapy, and the possibility of extending the indication and techniques used for mucosal resection.

Dissection↗
PubMed2005

Technical modification of the double-balloon endoscopy to access to the proximal side of the stenosis in the distal colon.

BACKGROUND: The inability to pass endoscopes beyond strictures is a considerable problem in patients with a colonic stricture. METHODS: In patients with bowel obstruction, we have modified the insertion method for double-balloon endoscopy with a long, transnasal decompression tube. OBSERVATIONS: We have succeeded in reaching the proximal side of the stricture from the oral approach across the entire small bowel in a patient. CONCLUSIONS: This modified double-balloon enteroscopy is useful for patients with bowel obstruction in whom a long decompression tube is already placed.

Colonic Diseases↗
PubMed2005

Double-balloon endoscopy.

PURPOSE OF REVIEW: Our strategy for small intestinal diseases has dramatically been brushed up with a novel technique, double-balloon endoscopy, which exhibits extremely better insertability and maneuverability compared with conventional methods. Double-balloon endoscopy has a potential to change radically the approach for the small intestinal diseases in the future. In this article, the publications on double-balloon endoscope will be reviewed. RECENT FINDINGS: A double-balloon endoscope can be inserted into deeper portions of the small intestine via both oral and anal approaches, and allows endoscopic observation as well as treatment for the entire small intestine without general anesthesia. Reports have been made on this method's safety and low frequency of complication: it is very useful for diagnosis and treatment of small intestinal diseases, including small intestinal bleeding, small intestinal tumor, stenosis of small intestine, and polyposis syndrome. SUMMARY: The development of double-balloon endoscopy enabled observation and treatment in the entire small intestine. The double-balloon endoscopy has a potential to be a standard of enteroscopy by replacing conventional push enteroscopy and intraoperative enteroscopy. In the near future, the double-balloon endoscopy, together with the capsule endoscopy, will be essential modalities for the management of small intestinal diseases.

Endoscopy, Gastrointestinal↗
PubMed2005

Cdx2 specifies the differentiation of morphological as well as functional absorptive enterocytes of the small intestine.

Many transcription factors are involved in the molecular control of intestinal epithelial cell differentiation. We report in this study that the transcription factor Cdx2 functions to define absorptive enterocytes during intestinal epithelial differentiation. Cdx2 is expressed in the villi of the normal small intestine. Intestinal metaplasia, which expresses Cdx2, occurs as a pathological condition in gastric mucosa. We have previously established Cdx2 transgenic mice expressing Cdx2 exclusively in the gastric epithelium. In this study using Cdx2 transgenic mice, we show that Cdx2 plays a key role in the differentiation of intestinal absorptive enterocytes. The gastric mucosa of Cdx2 transgenic mice was morphologically completely changed into intestinal metaplastic mucosa. Absorptive enterocytes had microvilli which were observed by electron microscope. The intestinal metaplastic mucosa of Cdx2 transgenic mice expressed sucrase and peptide transporter PepT1. Disaccharidase and leucine aminopeptidase activities were observed in the intestinal metaplastic mucosa. Glucose and amino acids were absorbed from Cdx2 transgenic mouse stomach with intestinal metaplasia. Finally we generated mice whose intestine was extensively excised. Cdx2 transgenic mice with intestinal metaplasia survived even after extensive intestinal excision. We successfully demonstrated that Cdx2 induced not only morphological but also functional absorptive enterocytes in the intestinal metaplastic mucosa in vivo. Our results suggest that Cdx2 is necessary and sufficient by itself to specify the development of intestinal absorptive enterocytes, whereas other factors which are expressed in the small intestine are not always necessary for the differentiation of functional absorptive enterocytes.

Amino Acids↗
PubMed2004

Development of gastric carcinoma from intestinal metaplasia in Cdx2-transgenic mice.

In the progression of chronic gastritis, gastric mucosal cells deviate from the normal pathway of gastric differentiation to an intestinal phenotype. Many epidemiologic studies have found an association between the formation of intestinal metaplasia and the development of gastric carcinoma. However, there is no direct evidence that shows intestinal metaplasia is a precursor lesion of gastric carcinoma, to date. We periodically examined the intestinal metaplastic mucosa of Cdx2-transgenic mice we have previously generated. Gastric polyps developed from intestinal metaplastic mucosa in all stomachs of Cdx2-transgenic mice examined. These gastric polyps consisted of intestinal-type adenocarcinoma that invaded the submucosa and muscularis propria and occasionally spread into the subserosa. p53 and APC gene mutations were recognized in the adenocarcinomas. The participation of APC and p53 gene mutations in gastric carcinogenesis from the intestinal metaplasia was verified by the Cdx2-transgenic mice, carrying Apc(Min) mutation or p53 deficiency, that developed gastric polyps much earlier than Cdx2 alone. We successfully showed that long-term intestinal metaplasia induces invasive gastric carcinoma. These results indicate that intestinal metaplasia itself plays a significant role in the genesis and progression of gastric carcinoma.

Adenocarcinoma↗
PubMed2004

Impaired production of gastric ghrelin in chronic gastritis associated with Helicobacter pylori.

Ghrelin is primarily secreted from the stomach and has been implicated in the coordination of eating behavior and weight regulation. The effects of Helicobacter pylori infection on plasma ghrelin concentration and gastric ghrelin production still have not been well known. We determined plasma ghrelin concentration in a total of 160 consecutive individuals with normal body mass index including 110 H. pylori-infected and 50 H. pylori-negative subjects. The expression levels of ghrelin mRNA and ghrelin-producing cells in the gastric mucosa were quantified with real-time quantitative RT-PCR and immunohistochemistry, respectively. The severity of gastric atrophy was evaluated by serum pepsinogen concentrations. Plasma ghrelin concentration, gastric ghrelin mRNA, and ghrelin-positive cell numbers in gastric mucosa were significantly lower in H. pylori-infected subjects. The decrease in plasma ghrelin concentration in H. pylori-positive subjects was accompanied by an attenuation of ghrelin mRNA expression and a reduction of ghrelin-positive cell numbers in the gastric mucosa. Moreover, lower serum pepsinogen I concentrations and I/II ratio were significantly associated with lower plasma ghrelin concentrations in H. pylori-positive subjects. These findings suggest that impaired gastric ghrelin production in association with atrophic gastritis induced by H. pylori infection accounts for the decrease in plasma ghrelin concentration.

Chronic Disease↗
PubMed2004

Involvement of syntaxin 4 in the transport of membrane-type 1 matrix metalloproteinase to the plasma membrane in human gastric epithelial cells.

Membrane-type 1 matrix metalloproteinase (MT1-MMP) localized on the plasma membrane plays a central role in various normal biological responses including tissue remodeling, wound heeling, and angiogenesis and in cancer cell invasion and metastasis, by functioning as a collagenase and activating other matrix metalloproteinases. In order to elucidate the molecular mechanism of the MT1-MMP targeted localization on the plasma membrane, we examined the participation of syntaxin proteins in MT1-MMP intracellular transport to the plasma membrane in human gastric epithelial AGS cells. Western blotting showed that syntaxin 3 and 4 proteins, which are known to function in intracellular transport towards the plasma membrane, were expressed in AGS cells. Immunocytochemistry revealed that transient transfection of AGS cells with dominant-negative mutant syntaxin 4 decreased plasma membrane MT1-MMP expression. In contrast, transient transfection with either dominant-negative mutant syntaxin 3 or 7 did not affect MT1-MMP localization on the plasma membrane. Cell surface biotinylation assay and Matrigel chamber assay demonstrated that stable transfection with dominant-negative mutant syntaxin 4 decreased the amount of MT1-MMP on the plasma membranes and inhibited the cell invasiveness. We suggest that syntaxin 4 is involved in the intracellular transport of MT1-MMP toward the plasma membrane.

Biological Transport↗