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Junji Yamamoto

Publications and source records attributed to Junji Yamamoto.

At least 37 records · Page 2Linked to original sources
PubMed2005

Image-diagnostic features of mature cystic teratomas of the pancreas: report on two cases difficult to diagnose preoperatively.

This report documents the findings of two rare cases of mature cystic teratoma of the pancreas. Although they could not be diagnosed preoperatively, our retrospective report suggests that the combined diagnosis of ultrasonography (US), enhanced computed tomography (CT), and magnetic resonance cholangiopancreatography (MRCP) might allow differentiation from other cystic lesions such as mucinous cystic tumors (MCTs) and intraductal papillary-mucinous tumors (IPMTs). Since the cystic teratomas were both filled with keratinous and sebaceous material, they were echogenic, appearing as solid masses on US. Enhanced CT showed their cystic nature, with values slightly higher than water, and MRCP revealed defects of internal signals.

Female↗
PubMed2005

Prognostic factors of surgical resection in middle and distal bile duct cancer: an analysis of 55 patients concerning the significance of ductal and radial margins.

BACKGROUND: The surgical outcome of middle and/or distal bile duct cancer remains unsatisfactory. Although the resectional margin is known to be a predictive factor, the prognostic significance of a positive ductal margin and other radial margin has never been evaluated independently. METHODS: The clinicopathologic data of 55 patients who had undergone surgical resection for middle and/or distal bile duct cancer between 1987 and 2003 were reviewed retrospectively. The surgical procedures consisted of pancreatoduodenectomy in 42 patients (76%), extrahepatic bile duct resection in 8 patients (15%), major hemihepatectomy (Hx) in 3 patients (5%), and pancreatoduodenectomy plus Hx in 2 patients (4%). In all the patients, intraoperative diagnosis of the ductal margins was performed using frozen sections. Twenty-one clinicopathologic factors, including the status of the ductal margins and of other radial margins, were evaluated using univariate and multivariate analyses. RESULTS: The overall 5-year survival rate and the median survival time were 24% and 38 months, respectively. There were 4 (7%) postoperative deaths. Fifteen of the remaining 51 patients (29%) were determined to have positive hepatic-side ductal margins during operation, and 14 of them underwent additional resection of the bile duct (1.6[range, 1-3] times, on average). As a result, hepatic-side ductal margin (hm) and duodenal-side ductal margin were found to be positive in 6 and 0 patients on the final pathologic analysis, respectively. Two of the 6 patients (33%) with positive hm have developed ductal recurrence so far, but the status of hm was not found to be a significant predictor. The depth of neoplastic invasion into the bile duct wall, pancreatic invasion, radial margin, and blood transfusion were significant prognostic factors by the univariate analysis. Multivariate analysis revealed that the depth of neoplastic invasion and blood transfusion were the independent prognostic factors. CONCLUSIONS: In the treatment of middle and distal bile duct cancer, it is of importance to secure a negative radial margin, although it may be less beneficial to obtain a negative hm. Surgeons should make efforts to obtain negative radial margins and to avoid blood transfusion.

Adult↗
PubMed2004

Apoptotic speck protein-like, a highly homologous protein to apoptotic speck protein in the pyrin domain, is silenced by DNA methylation and induces apoptosis in human hepatocellular carcinoma.

We have identified a novel gene encoding a pyrin domain protein of 89 amino acids that is expressed in various tissues including liver, brain, and spleen. The protein is highly homologous to the pyrin domain of apoptosis-associated speck-like protein (ASC). Therefore, we termed it ASC-like (ASCL). We found that ASCL gene was densely and frequently (80%) methylated in hepatocellular carcinoma (HCC) cell lines. In contrast, normal liver samples did not show any significant methylation. This aberrant methylation correlated well with the suppression of RNA expression. Furthermore, a demethylating agent, 5-aza-2'-deoxycytidine, reactivated the ASCL expression in the methylation-silenced cells, indicating that ASCL is silenced by the associated DNA methylation. ASCL methylation was also found in primary HCC (4 of 17 samples), although the frequency was less than that in cell lines. In addition, we found that ASC was also methylated in primary samples (6 of the 17). Interestingly, either ASCL or ASC methylation was observed in 53% (9 of the 17) of primary HCC samples. Significantly, the restoration of ASCL in the methylation-silenced cells demonstrated growth suppression in colony formation assay. This growth suppression effect of ASCL was supported by apoptotic changes observed in ASCL-transfected cells in which annexin-V binding was positive and caspase-3 was activated. Based on the methylation-silencing and the growth suppression activity, we propose that ASCL plays a significant role in the development of HCC.

Amino Acid Sequence↗
PubMed2004

Reconstruction of hepatic or portal veins by use of newly customized great saphenous vein grafts.

BACKGROUND AND AIMS: Segmental resection of major hepatic veins or the portal vein is sometimes required if one is to secure adequate surgical margins from hepatic or pancreatic malignancies. An external iliac vein is widely sacrificed as a vein graft to replace the defect, but this is associated with postoperative edema of the lower leg. We developed a new method for constructing the great saphenous vein to interpose the hepatic or portal veins. PATIENTS AND METHODS: The great saphenous vein was divided transversely into three sections, which were aligned side-to-side. The three pieces were anastomosed to make a sheet 3 x 2 cm, which was rolled up into a cylindrical form of approximately 1 cm in diameter and 2 cm in length. We applied the finished vein grafts to interpose the major hepatic veins in three patients with metastatic liver tumors and the portal vein in two patients with pancreatic malignancies in cylindrical form and to reconstruct the portal vein in one patient with a pancreas cancer, using a three-row sheet as a patch graft. RESULTS: No patient developed venous thrombosis of the graft or edema of the lower leg. CONCLUSIONS: The newly customized vein graft was safe and useful for the reconstruction of the major hepatic or portal veins.

Aged↗
PubMed2004

Natural examples of olivine lattice preferred orientation patterns with a flow-normal a-axis maximum.

Tectonic plate motion is thought to cause solid-state plastic flow within the underlying upper mantle and accordingly lead to the development of a lattice preferred orientation of the constituent olivine crystals. The mechanical anisotropy that results from such preferred orientation typically produces a direction of maximum seismic wave velocity parallel to the plate motion direction. This has been explained by the existence of an olivine preferred orientation with an 'a-axis' maximum parallel to the induced mantle flow direction. In subduction zones, however, the olivine a axes have been inferred to be arranged roughly perpendicular to plate motion, which has usually been ascribed to localized complex mantle flow patterns. Recent experimental work suggests an alternative explanation: under conditions of high water activity, a 'B-type' olivine preferred orientation may form, with the a-axis maximum perpendicular to the flow direction. Natural examples of such B-type preferred orientation are, however, almost entirely unknown. Here we document widespread B-type olivine preferred orientation patterns from a subduction-type metamorphic belt in southwest Japan and show that these patterns developed in the presence of water. Our discovery implies that mantle flow above subduction zones may be much simpler than has generally been thought.

Journal Article↗
PubMed2004

Bloodless liver resection using the monopolar floating ball plus ligasure diathermy: preliminary results of 16 liver resections.

Blood loss during liver transection and ischemia-reperfusion injury associated with hepatic inflow occlusion are significant drawbacks during liver surgery. Sixteen patients underwent liver resection using the Monopolar Floating Ball (FB) plus LigaSure (LS) diathermy without occlusion of the hepatoduodenal ligament (group FB-LS). The liver parenchyma was precoagulated using the FB, and the uncovered tiny vessels were sealed using LS. Surgical outcomes were retrospectively compared with 16 well matched patients who underwent liver resection using the conventional clamp crushing method with Pringle's maneuver (group CC). The amount of blood loss during liver transection was significantly less in group FB-LS than in group CC [200 ml (0-990 ml) vs. 480 ml (120-1800 ml); p = 0.006]. The median time it took to complete the liver transection was significantly longer in group FB-LS than in group CC [144 minutes (43-335 minutes) vs. 58 minutes (18-94 minutes); p < 0.0001]. Hepatic inflow occlusion was temporally used in five patients in group FB-LS to achieve hemostasis in hepatic venous tributaries for 6, 10, 19, 26, and 61 minutes, respectively. Using these two electronic devices allows liver resection to be safely performed, with the advantage of minimal blood loss and a reduced inflow occlusion period compared to the conventional method. The major disadvantage may be a slower transection speed. A prospective randomized trial is needed to clarify the clinical benefits of liver resections performed using this novel technique.

Adult↗
PubMed2004

Surgery for multiple hepatic colorectal metastases.

The purpose of this review is to address three important questions concerning hepatic resection for multiple colorectal metastases. (1) Is the number of tumors truly a significant prognostic factor? (2) Are patients with four or more tumors contraindicated for hepatic resection? (3) Up to how many nodules should we attempt to resect? Although the efficacy of surgical resection for one to three hepatic metastases is clear, based on several reports, the literature regarding the resection of four or more metastatic lesions is conflicting. Review of the data at our institutions showed that the number of tumors was a significant prognostic factor, because patient survival after liver resection for multiple metastases was worse than that for single metastasis. However, patients with two or three nodules and those with four or more nodules showed the same survival curves, or those with four or more metastases fared even better. Therefore, patients with four or more metastases should be considered for hepatic resection. The maximum number of hepatic tumors in longterm survivors reported in the literature has been increasing, and the limit for the number of respectable metastases has not yet been determined. Because liver resection is still the only treatment that offers a cure, surgery for multiple metastases may be justified as long as the operation is safe and technically feasible.

Colorectal Neoplasms↗
PubMed2004

Extended left hepatectomy by severing all major hepatic veins with reconstruction of the right hepatic vein.

Curative liver resection is technically challenging when multiple liver metastases from colon cancer involve the confluence of the three major hepatic veins. We report two cases of successful extended left hemihepatectomy achieved by severing all of the major hepatic veins together with the wall of the inferior vena cava, to resect liver metastases from colon cancer. Reconstruction of the right hepatic vein was done after unroofing the right anterior area of the liver with a direct anastomosis of the right hepatic vein. We did not need to perform total vascular exclusion or portovenous shunting during the liver transection. This simple and safe method can increase the surgical indications for previously unresectable tumors.

Aged↗
PubMed2004

EMR combined with chemoradiotherapy: a novel treatment for superficial esophageal squamous-cell carcinoma.

BACKGROUND: Esophagectomy or chemoradiotherapy (CRT) are the procedures of choice for patients with superficial esophageal squamous-cell carcinoma. However, esophagectomy is highly invasive, and CRT is associated with the risk of local failure. A study was conducted of a novel treatment, EMR combined with CRT, for patients with superficial esophageal carcinoma. EMR was performed for the purpose of complete local tumor control and chemoradiotherapy was performed for regional and distant control. METHODS: EMR combined with CRT was performed for patients with esophageal carcinoma invading the muscularis mucosae or upper submucosa who refused esophagectomy. The planned treatment after EMR was 40 to 46 Gy of external beam radiation to the mediastinum, including the supraclavicular fossa or cardia. Chemotherapy was given during weeks 1 and 5 (5-fluorouracil, 700 mg/m(2) per 24 hours in a 120-hour infusion, and cisplatin 15 mg/m(2) per day intravenously on days 1 to 5). RESULTS: During the study period, 16 patients underwent EMR combined with CRT (EMR plus CRT group) and 39 patients with similar stage cancer underwent esophagectomy (surgical resection group). None of the patients in the EMR plus CRT group have had local recurrence or metastasis. Overall survival rates at 5 years in the EMR plus CRT and surgical resection groups were estimated to be, respectively, 100% and 87.5%. CONCLUSIONS: Although this study was not randomized, the results suggest that EMR combined with CRT is a safe and effective method for treating patients with superficial esophageal carcinoma. The results were equivalent or, in view of the lower degree of invasiveness, superior to surgical resection.

Aged↗
PubMed2004

Endoscopic clip application for closure of esophageal perforations caused by EMR.

BACKGROUND: With increasing use of EMR for early stage esophageal carcinoma, the number of cases of iatrogenic esophageal perforation is likely to increase. This study evaluated the results of endoscopic clip application for treatment of perforations caused by EMR in patients with esophageal carcinoma. METHODS: Among 185 patients who underwent EMR for esophageal carcinoma, esophageal perforation occurred in 3 patients (1.6%). Metallic clips were immediately applied endoscopically to close the perforations. OBSERVATIONS: All 3 patients were observed closely and were managed conservatively (intravenous hyperalimentation, antibiotics) after closure of the perforation. They were discharged without any further serious complication. CONCLUSIONS: When esophageal perforation caused by EMR is immediately recognized, endoscopic application of metallic clips is appropriate therapy. However, patients must be carefully monitored for the development of generalized mediastinitis.

Aged↗
PubMed2004

[Primary duodenal carcinoma].

Primary duodenal carcinoma (PDC) is rare and generally considered to have a low resectability rate and dismal prognosis. PDCs as well as other carcinomas in the pancreatic head are treated by curative pancreaticoduodenectomy. In a selected patient, segmental resection or local resection of the duodenum is indicated. Early PDC can be treated by endoscopic resection. There is an increased risk in patients with familial adenomatous polyposis and adenomas in the duodenum.

Adenomatous Polyposis Coli↗
PubMed2003

Strategies for surgical treatment of gallbladder carcinoma based on information available before resection.

HYPOTHESIS: Precise preoperative staging for gallbladder carcinoma is difficult, despite recent advances in hepatobiliary imaging. However, the most accurate preoperative staging may be possible by integrating preoperative key data. OBJECTIVE: To establish useful strategies for the surgical treatment of gallbladder cancer based on information available before resection. DESIGN: Retrospective review. SETTING: University hospital and tertiary referral cancer center. PATIENTS AND METHODS: From January 1, 1978, through March 31, 2001, 152 patients with gallbladder cancer underwent surgical resection with curative intent. Preoperative diagnoses of the T factor (image-T) and N factor (image-N) in the TNM classification were determined by evaluating all findings of diagnostic imaging, including ultrasonography, enhanced computed tomography, endoscopic ultrasonography, and angiography. The distribution of lymph node metastasis and prognostic factors were also analyzed. RESULTS: The overall diagnostic accuracy for image-T was 52.6% (95% confidence interval, 44.7%-60.6%) and was lower in patients with pT1 and pT2 disease (37.2% and 33.9%, respectively). However, image-T was a significant predictor of lymph node metastasis and patient outcome. Preoperative staging for N was more difficult, with only 24.5% (95% confidence interval, 12.4%-36.5%) of the node-positive patients being correctly diagnosed. An analysis of harvested lymph nodes showed that the cystic, pericholedochal, and posterosuperior peripancreatic nodes were the most prevalent sites of metastasis, and these were considered key nodes for the lymphatic spread of gallbladder cancer. By combining data on image-T and positivity of these key nodes, more accurate TNM staging was possible. Although an extended lymph node dissection provided significantly better survival in patients with pN2 disease, there was no survival advantage to more radical operations, including bile duct resection or pancreaticoduodenectomy. CONCLUSIONS: Although precise preoperative TNM staging for gallbladder carcinoma was difficult, the most accurate staging before resection was possible by integrating image-T classification and data from the intraoperative histopathologic examination of key lymph nodes. Based on this staging, we propose algorithms for the surgical treatment of gallbladder carcinoma.

Adult↗
PubMed2003

Surgical treatment of intraductal papillary-mucinous tumor (IPMT) of the pancreas: operative indications based on surgico-pathologic study focusing on invasive carcinoma derived from IPMT.

BACKGROUND/PURPOSE: Between 1979 and 2000, 51 patients with intraductal papillary-mucinous tumor (IPMT) of the pancreas underwent surgical resection. METHODS: The patients were reviewed to disclose the surgical pathology of invasive carcinoma derived from IPMT and to determine the surgical indications for IPMT on the basis of the pathologic findings. RESULTS: The incidence of invasive carcinoma derived from IPMT according to the localization of the tumor was as follows: 4/9 (44%) in the main pancreatic duct (MPD type), 4/9 (44%) showing ductal spread from the MPD to branch ducts (mixed type), and 2/33 (6%) in the 2 branch duct (branch type). The maximal size of the intraductal spread of invasive carcinomas (8 of 18 cases in the MPD and mixed type together and 2 of 33 cases in the branch type) was as follows: 6/8 (75%) in the MPD and mixed type were over 6 cm in size, and the 2-branch-type invasive carcinomas were within the 3-cm size range. CONCLUSIONS: We concluded that for both invasive and noninvasive IPMTs, surgical resection was necessary for any MPD or mixed-type IPMTs, and that surgical resection was appropriate for branch-type lesions larger than or equal to 3 cm in diameter, or for lesions smaller than 3 cm showing rapid growth on clinical images.

Aged↗
PubMed2003

Relationship between histopathologic gastritis and mucosal microvascularity: observations with magnifying endoscopy.

BACKGROUND: The purpose of this study was to determine the usefulness of magnifying endoscopy for the diagnosis of Helicobacter pylori-induced histopathologic gastritis. METHODS: A total of 92 patients scheduled to undergo routine endoscopic examination were enrolled. After routine endoscopic examination, 3 sites in the stomach were studied by magnified observation. Visualized collecting venulae were classified into the following 3 patterns: regular, irregular, and obscured. The sites observed by magnifying endoscopy were assessed histopathologically with an Updated Sydney System; 4 morphologic parameters (activity, inflammation, atrophy, metaplasia) were assessed and graded from 0 to 3. RESULTS: The regular pattern cases were negative for H pylori infection at all sites observed by magnifying endoscopy (antrum greater curve, 0/11; body greater curve, 0/24; body lesser curve, 0/23). The scores for all 4 morphologic parameters were significantly lower in the regular pattern group than the irregular and obscured groups (p < 0.01). The value of the atrophy parameter in the irregular group was significantly higher than that in the obscured group (p < 0.05 for a single test of hypothesis; correction for multiple testing of data removed significance). CONCLUSION: Visibility of collecting venulae in the gastric mucosa is influenced by H pylori-induced histopathologic gastritis. Magnifying endoscopy is useful for the diagnosis of histopathologic gastritis.

Cohort Studies↗