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Ferrous-carbon monoxide bound form of cytochrome P450cam (CO-P450cam) has two infrared (IR) CO stretching bands at 1940 and 1932 cm(-1). The former band is dominant (>95% in area) for CO-P450cam free of putidaredoxin (Pdx), while the latter band is dominant (>95% in area) in the complex of CO-P450cam with reduced Pdx. The binding of Pdx to CO-P450cam thus evokes a conformational change in the heme active site. To study the mechanism involved in the conformational change, surface amino acid residues Arg79, Arg109, and Arg112 in P450cam were replaced with Lys, Gln, and Met. IR spectroscopic and kinetic analyses of the mutants revealed that an enzyme that has a larger 1932 cm(-1) band area upon Pdx-binding has a larger catalytic activity. Examination of the crystal structures of R109K and R112K suggested that the interaction between the guanidium group of Arg112 and Pdx is important for the conformational change. The mutations did not change a coupling ratio between the hydroxylation product and oxygen consumed. We interpret these findings to mean that the interaction of P450cam with Pdx through Arg112 enhances electron donation from the proximal ligand (Cys357) to the O-O bond of iron-bound O(2) and, possibly, promotes electron transfer from reduced Pdx to oxyP450cam, thereby facilitating the O-O bond splitting.

We hereby reported a case of 60-year old man with superficial esophageal cancer complicated with idiopathic muscular hypertrophy of the esophagus. Endoscopic ultrasonography and CT showed the thickness of esophageal muscular layer, but the accurate diagnosis could not be entertained before operation. Idiopathic muscular hypertrophy of the esophagus is an entity rarely encountered, and most cases are diagnosed at postmortem examination. Only a few cases have been reported regarding its clinical symptoms and images. The etiology remains to be elucidated, and the pathologic features are characterized by significant thickness of inner circular muscular layer of esophagus without degeneration of plexus and ganglionic cells. This case report deals with superficial esophageal cancer complicated with idiopathic muscular hypertrophy of esophagus. Literature review is also included.

Recently, proton pump inhibitors and the laparoscopic Nissen operation were introduced clinically for the treatment of reflux esophagitis. Although the laparoscopic Nissen operation is becoming increasingly common world wide, medical therapy is still considered the treatment of choice for reflux esophagitis. The indications for surgical treatment of reflux esophagitis are: 1) patients resistant to medical therapy, especially younger patients; 2) free reflux patients; 3) patients with shortened esophagus or stenosis; and 4) patients with respiratory complications. The selection of surgical method is as follows: 1) the fundamentally laparoscopic Nissen procedure should be selected for relatively younger patients with good peristalsis in the esophageal body; 2) the laparoscopic Toupet method or the Dor method should be selected for patients with poor esophageal peristalsis; 3) the Tokai University method is suitable for patients with any condition; 4) the Collis-Nissen method, modified Deitel method, or Deitel-Nissen method is suitable for patients with acquired short esophagus; 5) resection and jejunal interposition or double tract reconstruction should be performed in patients with severe stenosis. Numerous problems remain in the surgical treatment of reflux esophagitis.

Barrett's mucosa consists of metaplastic columnar epithelium (specialized columnar epithelium) of the esophagus. Recently, "short-segment Barrett's esophagus (SSBE)" was proposed. In the present study, we examined immunohistochemical mucin expression and the Ki-67 labeling index (LI) of SSBE, in 5-15 mm lengths. All 27 SSBE cases showed gastric mucin (MUC5AC, HGM, MUC6). CD10 and MUC2, which were markers of intestinal phenotypes, were detected in 13 (48.1%) and 14 (51.9%) of the 27 SSBE cases. Ki-67 LI of SSBE positive cases for CD10 was 23.6 %, while that of SSBE negative cases for CD10 was 14.4 % (p < 0.05). SSBE cases were divided into two groups: one was gastric epithelium type with low Ki-67 LI, and the other was metaplastic epithelium with intestinal metaplasia and high Ki-67 LI. The latter group was suggested to be more important as a premalignant lesion of esophageal adenocarcinoma.

Background/aims: Improvement of surgical skills and postoperative management has allowed longer postoperative survival for patients with esophageal cancer, among those some develop gastric tube cancer. We analyzed the characteristics of such patients we encountered as well as of reported cases of Japan. Furthermore, we investigated if Helicobacter pylori plays a role in carcinogenesis of the gastric tube in our cases., Methodology: We analyzed the clinicopathological features of our 8 patients with gastric tube cancer from 1991 to 2000 as well as the status of H. pylori on the gastric tube biopsy. Moreover the features of gastric tube cancer from domestic reported cases up to the year 2000 were also summarized., Results: According to the review of our cases, the frequent tumor location was the distal portion of the gastric tube. Seventy-eight percent were detected in early stage during postoperative follow-up, 71% of those were treated endoscopically. No cases showed H. pylori positivity. From the previous domestic reports, early cancer is increasing as the screening becomes popular. Type 0-IIa and 0-IIc were the most popular images for early cancer, while type 2 and 3 were for advanced cancer., Conclusions: The carcinogenesis of the gastric tube seemed not to be related to H. pylori. Subdermal route of reconstruction at esophagectomy seemed superior regarding early recognition of gastric tube cancer and easiness of its treatment.

Background: The aim of this study was to determine by radioisotope use whether the sentinel lymph node concept is applicable to esophagogastric cancers. In addition, we examined radioactivities of hot nodes and compared them with the sensitivity of a gamma probe., Methods: The subjects were 44 patients, 23 with esophageal cancer and 21 with gastric cancer. The day before surgery, patients underwent endoscopic submucosal injection of 184 MBq of Tc-99m tin colloids into sites surrounding the tumor. Radioisotope activities of lymph nodes dissected at surgery were measured with a well-typed gamma detector and each lymph node was categorized as a hot or cold node. Histopathology of the lymph nodes was examined by hematoxylin and eosin staining. Radioisotope activities and histopathological results were compared to determine whether radioisotope flow reflects lymphatic flow to regional lymph nodes. The sensitivity of a gamma probe was measured in a laboratory study and the relation between the radioisotope activities of hot nodes and the detection sensitivity of the gamma probe was examined., Results: Histopathological examination revealed lymph node metastasis in 18 of the 44 patients. In 15 of these 18 patients, metastatic foci were recognized in at least one hot node. Subsequent analysis was performed on the 36 patients in whom tumor invasion was confined to the muscle layer and in whom endoscopic clippings had not been applied. Lymph node metastases were observed in 12 of these 36 patients. In these 12 patients, at least one hot node was positive for metastasis. The laboratory study revealed that the gamma probe was able to detect radioisotope activities of >/=0.02 micro Ci. Thirty-two of 63 (51%) esophageal cancer hot nodes and 16 of 86 (19%) gastric cancer hot nodes showed radioisotope activities below the detection sensitivity of the gamma probe., Conclusion: The sentinel lymph node concept is applicable to patients with esophageal and gastric cancers; however, further studies are necessary to identify hot nodes accurately using gamma probes.

Background: A retrospective study was performed to determine the indications for positron emission tomography (PET) using [(18)F]fluorodeoxyglucose (FDG) in patients with esophageal cancer, including those with early cancer, and to investigate whether the tumor-to-normal ratio (T/N ratio) could be used as a substitute for the standardized uptake value (SUV)., Methods: Thirty-six patients were included in the study. Thirty-one patients who had 36 biopsy-proven lesions (35 squamous cell carcinomas and one small cell carcinoma) underwent PET study prior to treatment. PET images were evaluated visually and the relationship between the depth of invasion and the PET findings were examined in 22 lesions of 19 patients from whom specimens were obtained from the primary tumor by surgery or endoscopic mucosal resection. PET results were also compared with computed tomography (CT) and endoscopic ultrasonography (EUS) for detection of regional lymph node metastases in 18 patients who underwent extended lymph node dissection. Five patients underwent PET studies for the detection of recurrence and the PET findings were compared with their CT findings. The T/N ratio and the SUV were calculated for 20 primary tumors., Results: Among the 15 tumors that were pT1b or greater, all 15 were positive on PET and all seven of the lesions confined to the mucosa (Tis or T1a) were negative. The sensitivity, specificity and accuracy of detecting nodal involvement were, respectively, 37.5, 96.1 and 88.3% by CT, 30.8, 88.5 and 81.0% by EUS and 41.7, 100 and 92.2% by PET. More sites of recurrence were detected by PET than by CT. There was no statistically significant correlation between the SUV and the T/N ratio., Conclusions: PET imaging can detect primary esophageal cancer with a depth of invasion of T1b or greater, but Tis and T1a tumors are undetectable. PET seems to be more accurate than CT or EUS for diagnosing lymph node metastasis. The T/N ratio cannot be used as a substitute for the SUV.