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Biomedical subjects

Masao Omata

Publications and source records attributed to Masao Omata.

At least 37 records · Page 2Linked to original sources
PubMed2006

Selection of liver-transplant candidates for adult-to-adult living donor liver transplantation as the only surgical option for end-stage liver disease.

The selection of living donor liver transplantation (LDLT) recipients in regions where deceased donor liver transplantation (DDLT) is rarely performed might be different from that in other centers at which LDLT is an alternative option to DDLT. Records of adult (age > or = 18 yr) patients referred to our center were reviewed to analyze the selection process of LDLT candidates. Among the 533 LDLT candidates, 165 (31%) were rejected due to recipient issues. Advanced hepatocellular carcinoma (HCC) was the most common reason for rejection (n = 55). Among the remaining recipients, 120 patients (22%) were rejected due to donor issues. LDLT was eventually performed in 249 (47%) of the evaluated recipients. There are few options for candidates who are unable to find live donors in regions where DDLT is unrealistic. A more effective and precise approach to recipient and donor evaluation should be pursued.

Adolescent↗
PubMed2006

A modified Japan Integrated Stage score for prognostic assessment in patients with hepatocellular carcinoma.

BACKGROUND: For patients with hepatocellular carcinoma (HCC), the selection of effective therapeutic options depends on a reliable prognostic assessment of both the tumor characteristics and liver impairment. This study sought to provide a modified Japan Integrated Stage (m-JIS) score to predict more accurately the survival of patients with HCC. METHODS: We analyzed the records of 42,269 patients diagnosed with HCC that were registered between 1992 and 1999 in a nationwide Japanese database. The m-JIS score was calculated from the tumor-node-metastasis stage and the grade of liver damage as defined by the Liver Cancer Study Group of Japan. The predictive accuracy for patient survival based on the m-JIS score was compared with that determined by the modified Cancer of the Liver Italian Program (m-CLIP) score using the cross-validation method. RESULTS: Patients were divided randomly into two groups, a training sample for construction of prediction models (n = 21,127 patients with 8,458 deaths) and a validation sample for assessment of those prediction models (n = 21,142 patients with 8,434 deaths). Both the m-JIS score and the m-CLIP score showed good discriminatory ability in the training sample. In the validation sample, the residuals of prediction based on the m-JIS score were smaller than those of the m-CLIP score (P < 0.0001). CONCLUSIONS: The m-JIS scoring system had better predictive accuracy than the m-CLIP score system for survival of Japanese patients with HCC.

Carcinoma, Hepatocellular↗
PubMed2006

Prediction of hepatic encephalopathy development in patients with severe acute hepatitis.

To identify factors predicting the development of hepatic encephalopathy, 164 patients with severe acute hepatitis (SAH), defined as acute hepatitis having a prolonged prothrombin time (PT) of < 40% activity but without hepatic encephalopathy, were prospectively observed at 57 major liver centers in Japan. From the data of 65 patients enrolled from 1997 to 1998, a prediction equation was developed by multiple logistic regression analysis and prospectively evaluated using the data of 99 patients since 1999. Of the 164 patients with SAH, 51 (31%) developed hepatic encephalopathy. From the etiologic viewpoint, the percentages of patients developing encephalopathy were highest in non-A-E hepatitis (41.9%). A predictive model, logit(p) = 0.084 x age (year)+ 0.129 x serum total bilirubin (TB, in mg/dL)-0.158 x prothrombin time (%)-2.434, was developed. In conclusion, old age, prolonged PT, elevation of TB, and non-A-E hepatitis are potential risk factors for developing encephalopathy in SAH.

Adult↗
PubMed2006

Urinary liver-type fatty acid binding protein as a useful biomarker in chronic kidney disease.

BACKGROUND: We reported that urinary L-FABP reflected the progression of chronic kidney disease (CKD). This study is aimed to evaluate the clinical significance of urinary liver type fatty acid binding protein (L-FABP) as a biomarker for monitoring CKD. METHODS: Urinary L-FABP was measured using human L-FABP ELISA kit (CMIC.Co., Ltd., Tokyo, Japan). The relations between urinary L-FABP and clinical parameters were evaluated in non-diabetic CKD (n = 48) for a year. In order to evaluate the influence of serum L-FABP derived from liver upon urinary L-FABP, both serum and urinary L-FABP were simultaneously measured in patients with CKD (n = 73). RESULTS: For monitoring CKD, the cut-off value in urinary L-FABP was determined as 17.4 microg/g.cr. by using a receiver operating characteristics (ROC) curve. Renal function deteriorated significantly more in patients with 'high' urinary L-FABP (n = 36) than in those with 'low' L-FABP (n = 12). The decrease in creatinine clearance was accompanied by an increase in urinary L-FABP, but not in urinary protein. Serum L-FABP in patients with CKD was not correlated with urinary L-FABP. CONCLUSION: Urinary excretion of L-FABP increases with the deterioration of renal function. Serum L-FABP did not influence on urinary L-FABP. Urinary L-FABP may be a useful clinical biomarker for monitoring CKD.

Adult↗
PubMed2006

Successful outcomes of a novel endoscopic treatment for GI tumors: endoscopic submucosal dissection with a mixture of high-molecular-weight hyaluronic acid, glycerin, and sugar.

BACKGROUND: Endoscopic submucosal dissection (ESD) has recently been developed for endoscopic treatment of GI tumors, which enables us to resect even large tumors en bloc. However, a considerable frequency of perforation has become another problem. The best way to prevent perforation is to create a sufficient submucosal fluid cushion (SFC). The aim of this study is to find out the feasibility of ESD by using a mixture of 1900 KDa hyaluronic acid (Suvenyl) and a 10% glycerin plus 5% fructose solution (Glyceol). METHODS: Sixty-seven consecutive GI tumors in 54 patients who met indication criteria of ESD were enrolled. The mixing ratios of Suvenyl and Glyceol were 1:3 for esophageal/colorectal tumors and stomach tumors with scar, and 1:7 for stomach tumors without scar. After creation of SFCs, mucosal incision around the tumors and submucosal dissection under the tumors were made by cutting devices. The clinical outcomes were investigated. RESULTS: Mean resected and tumor sizes were 38.6 and 25.6 mm, respectively. Perforation occurred in one colon tumor with severe fibrosis (1.5%), which was managed by endoscopic clipping without salvage surgery. No blood transfusion was performed. In one stomach and in one rectal tumor (3%), endoscopic hemostasis was necessary because of postoperative bleeding. Overall endoscopic and histologic en bloc resection rates were 94% (63/67) and 78% (52/67), respectively, and there was no recurrence after follow-up of 1 year. CONCLUSIONS: ESD when using a mixture of Suvenyl and Glyceol results in excellent outcomes, and this injection solution should be used for ESD.

Adjuvants, Immunologic↗
PubMed2006

Right-side shift of colorectal adenomas with aging.

BACKGROUND: Although it is known that right-side colon cancers increase with aging, the location of adenomas according to age has been controversial. Adenomas found at initial colonoscopies may be a mixture of polyps that arose at various earlier ages. OBJECTIVES: To elucidate the relationship between location and age at which adenomas actually developed. DESIGN: Prospective cohort study. SETTING: A large-scale health appraisal institution in Japan. PATIENTS: A total of 23,444 consecutive, asymptomatic Japanese who underwent total colonoscopy at their annual medical health check-up. INTERVENTIONS: We analyzed newly developed adenomas after confirmation of the absence of colorectal neoplasms by two serial total colonoscopies. MAIN OUTCOME MEASUREMENTS: The results of follow-up colonoscopies in 6304 subjects with no colorectal neoplasms at 2 initial colonoscopies were analyzed. The locations were separated into right-side colon and left-side colon from the splenic flexure. The locations of new adenomas found for the first time during the follow-up term were analyzed. RESULTS: A total of 1472 subjects developed new colorectal adenomas. In 1255 cases with single adenomas, the ratios of number of cases with right-side lesions to that with left-side lesions at the ages of <40 years, 40 to 49 years, 50 to 59 years, 60 to 69 years, and > or =70 years were 1.18, 1.00, 1.29, 1.31, and 1.89, respectively. In 217 cases with multiple adenomas found concurrently, the percentage of cases with adenomas only on the right side at the ages of <40 years, 40 to 49 years, 50 to 59 years, 60 to 69 years, and > or =70 years were 0%, 25%, 34%, 37%, and 63%, respectively. LIMITATIONS: Small lesions might have been missed even by 2 serial colonoscopies. CONCLUSIONS: Adenomas on the right-side colon increased with aging.

Adenoma↗
PubMed2006

Risk assessment for delayed hemorrhagic complication of colonic polypectomy: polyp-related factors and patient-related factors.

BACKGROUND: Hemorrhage is among the most serious complications of colorectal polypectomy and may occur after a longer postprocedure interval. OBJECTIVE: We aimed to elucidate the risk factors for delayed postpolypectomy hemorrhage, including both polyp characteristics and the general condition of the patients. DESIGN: Retrospective cohort study. PATIENTS: A total of 6617 cases of colorectal polypectomy was performed in 3138 consecutive patients in Japan. MAIN OUTCOME MEASUREMENTS: The risk factors for delayed postpolypectomy hemorrhage were assessed among polyp characteristics (form, size, histologic features) and the method of resection by unconditional logistic regression. Patient conditions (smoking, alcohol, hypertension, diabetes mellitus, hyperlipidemia) were compared between case-control pairs matched on polyp-related characteristics by conditional logistic regression. RESULTS: Hemorrhage occurred in 38 lesions (0.57%) of 37 patients (1.2%): 22 required endoscopic hemostasis and 1 required blood transfusion. Although polyp size was associated with the occurrence of delayed hemorrhage (10.0 +/- 6.9 mm in hemorrhage cases vs 5.6 +/- 3.8 mm in others, P < .0001), other polyp-related factors were not significant. Hypertension was a complication in 25 of 37 (68%) cases and in 21 of 74 (28%) matched controls, showing an adjusted odds ratio of 5.6 (95% CI 1.8-17.2, P = .001). Other patient characteristics were not significant. The interval between polypectomy and hemorrhage was significantly longer in patients with hypertension (median 6 days, range 2-14 days) than in those without hypertension (2.5 days, 1-9 days; P = .019). LIMITATIONS: This study does not provide information regarding prevention of hemorrhage. CONCLUSIONS: Hypertension is a significant risk factor for delayed colorectal postpolypectomy hemorrhage. The interval between polypectomy and hemorrhage can be as long as 14 days in the presence of hypertension.

Aged↗
PubMed2006

Hepatitis C virus core protein is a potent inhibitor of RNA silencing-based antiviral response.

BACKGROUND & AIMS: Persistent infection with hepatitis C virus (HCV) leads to chronic hepatitis and hepatocellular carcinoma (HCC). RNA interference (RNAi) may act as a host antiviral response against viral RNA. METHODS: The effects of RNAi on both the replicative intermediates and the internal ribosome entry site (IRES) of HCV were studied by using HCV-related short interfering RNA (siRNA) detection assay. The mechanism that permits HCV to escape RNAi was studied by using RNAi assay materials. RESULTS: These studies demonstrate that the Dicer, an RNase enzyme that generates short siRNA, can target and digest both the IRES and the replicative intermediate of HCV into siRNA of approximately 22 nucleotides. Further studies also show that Dicer can inhibit the replication of the HCV subgenomic replicon. However, the HCV core protein inhibits this RNAi and rescues the replication of the HCV subgenomic replicon through a direct interaction with Dicer. CONCLUSIONS: RNAi is a limiting factor for HCV infection, and the core protein suppresses the RNA silencing-based antiviral response. This ability of the core protein to counteract the host defense may lead to a persistent viral infection and may contribute to the pathogenesis of HCV.

Cell Line↗
PubMed2006

Prospective cohort study of transarterial chemoembolization for unresectable hepatocellular carcinoma in 8510 patients.

BACKGROUND & AIMS: To elucidate the survival of the patients with unresectable hepatocellular carcinoma (HCC) who underwent transcatheter arterial lipiodol chemoembolization (TACE) and to analyze the factors affecting the survivals. METHODS: During the last 8 years, a nationwide prospective cohort study was performed in 8510 patients with unresectable HCC who underwent TACE using emulsion of lipiodol and anticancer agents followed by gelatin sponge particles as an initial treatment. Exclusion criteria were extrahepatic metastases and/or any previous treatment prior to the present TACE. The primary end point was survival. The survival rates were calculated by the Kaplan-Meier method. The multivariate analyses for the factors affecting survival were evaluated by the Cox proportional hazard model. The mean follow-up period was 1.77 years. RESULTS: For overall survival rates by TACE, median and 1-, 3-, 5-, and 7-year survivals were 34 months, 82%, 47%, 26%, and 16%, respectively. Both the degree of liver damage and the tumor-node-metastasis (TNM) system proposed by the Liver Cancer Study Group of Japan demonstrated good stratification of survivals (P = .0001). The multivariate analyses showed significant difference in degree of liver damage (P = .0001), alpha-fetoprotein value (P = .0001), maximum tumor size (P = .0001), number of lesions (P = .0001), and portal vein invasion (P = .0001). The last 3 factors could be replaced by TNM stage. The TACE-related mortality rate after the initial therapy was .5%. CONCLUSIONS: TACE showed safe therapeutic modality with a 5-year survival of 26% for unresectable HCC patients. The degrees of liver damage, TNM stage, and alpha-fetoprotein values were independent risk factors for patient survival.

Aged↗
PubMed2006

Safety of argon plasma coagulation for hemostasis during endoscopic mucosal resection.

Showing the safety of argon plasma coagulation (APC) over mucosal defects during/after endoscopic mucosal resection (EMR), 2 studies using resected pig (ex vivo) and living minipig (in vivo) stomachs were performed. As an ex vivo study, APC was applied over mucosal defects in 2 groups; with prior submucosal saline injection and without injection. Only subtle tissue damage was observed in the injection group, whereas apparent damage was observed in the noninjection group. The damaged distances in depth significantly increased as the pulse duration increased and those at the pulse duration of 4 seconds, which might be maximal in clinical practice, were approximately 1 mm. As an in vivo study, APC was applied over mucosal defects immediately after EMR. Only subtle tissue damage was observed even at the pulse duration of 20 seconds as shown in the ex vivo study. APC can be performed safely over the mucosal defects during/after EMR.

Animals↗
PubMed2006

En bloc resection of a large semicircular esophageal cancer by endoscopic submucosal dissection.

A semicircular esophageal cancer, approximately 7 cm wide, was detected in the middle to lower esophagus of an 81-year-old gentleman during an esophagogastroduodenoscopy. Thorough examinations using chromoendoscopy and endoscopic ultrasonography led to preoperative diagnosis of an intramucosal tumor. With informed consent, the patient underwent endoscopic submucosal dissection (ESD), a novel endoscopic treatment. A successful en bloc resection by ESD was completed without complications. The resected specimen measured 72 mm by 35 mm, and the cancer was contained in an area of 66 mm by 32 mm. Histologic assessment revealed squamous cell carcinoma, microinvasive into the mucosal layer, but without vessel infiltration. Six months after ESD, mild stenosis remained, but dilation was no longer needed, and esophagogastroduodenoscopy with chromoendoscopy and biopsy revealed no residual or recurrent cancer.

Aged, 80 and over↗
PubMed2006

Submucosal injection of normal saline may prevent tissue damage from argon plasma coagulation: an experimental study using resected porcine esophagus, stomach, and colon.

Argon plasma coagulation (APC) is considered to be a safe thermocoagulation technique, but some reports show perforation and deformity during and after APC. In this study, we investigated the usefulness of prior submucosal injection for APC. APC over the mucosa was performed on fresh resected porcine esophagus, stomach, and colon with prior submucosal injection of normal saline (injection group) and without it (control group). The depth of tissue damage increased linearly with pulse duration up to the shallower submucosal layer in both groups. After that, tissue damage in the injection group remained confined to the shallower submucosal layer under any condition, whereas that in the control group continued to extend. The tissue damages of the injection groups were significantly (P<0.05) shallower than those of the control groups that reached the deeper submucosal layer in all the organs. Submucosal injection of normal saline before the application of APC may limit tissue damage and prevent perforation and deformity.

Animals↗
PubMed2006

Efficacy of peppermint oil as an antispasmodic during endoscopic retrograde cholangiopancreatography.

BACKGROUND: During endoscopic retrograde cholangiopancreatography (ERCP), hyoscine-N-butylbromide (Buscopan) or glucagon is used to inhibit duodenal motility. However, they may cause adverse effects. Peppermint oil has an antispasmodic effect and is used as a less hazardous antispasmodic during colonoscopy and upper gastrointestinal endoscopy. The purpose of the present paper was therefore to investigate peppermint as an antispasmodic for ERCP. METHODS: Forty patients were enrolled prospectively. They were assigned to four groups according to the peppermint oil concentration and site of administration: group 1, 20 mL of 1.6% solution around duodenal papilla; group 2, 20 mL of 1.6% solution both to the antrum of the stomach and around the duodenal papilla; group 3, 20 mL of 3.2% solution around the duodenal papilla; and group 4, 3.2% solution both to the antrum and around the duodenal papilla. Glucagon or hyoscine-N-butylbromide was added when duodenal peristalsis was not adequately diminished. Sixteen patients undergoing ERCP with glucagon were employed as historical controls. RESULTS: The ERCP was attempted in all except one patient in group 2 who had bleeding from invaded tumor to the duodenum. Peppermint administration equally reduced duodenal motility in the groups. Duodenal movement was none or mild in 69.2% of patients. The ERCP was successfully performed with peppermint alone in 91.4% of patients (37/39). Glucagon or hyoscine-N-butylbromide was needed in one patient each in groups 1 and 4. Serious complications related to peppermint oil did not occur. Inhibitory effect of peppermint appears to be identical to that of glucagon. CONCLUSION: Duodenal relaxation was obtained with 20 mL of 1.6% peppermint oil solution in the duodenum, but additional administration may be required. Peppermint oil is useful as an antispasmodic agent for ERCP.

Adult↗
PubMed2006

Helicobacter pylori status and the extent of gastric atrophy do not affect ulcer healing after endoscopic submucosal dissection.

BACKGROUND: Eradication therapy for Helicobacter pylori is effective in preventing peptic ulcer recurrence, but its efficacy in ulcer healing is still controversial. The effect of H. pylori on artificial ulcers after endoscopic resection is not known. The purpose of the present study was therefore to evaluate the influence of H. pylori infection on ulcer healing after endoscopic submucosal dissection (ESD). METHODS: One hundred and 10 patients who underwent ESD for gastric tumors, and for whom the infection status of H. pylori was confirmed before treatment, were included. The healing stage was studied by endoscopy performed at 8 weeks after ESD. In addition, 73 patients whose serum pepsinogen (PG) was evaluated before ESD, were divided into three groups: PG positive (PGI<or=70 ng/mL and I/II<or=3 ng/mL), strongly positive (PGI<or=30 ng/mL and I/II<or=2 ng/mL) and negative, to study the influence of atrophic gastritis on ulcer healing. RESULTS: Ulcer healing was observed in 85 patients (93%) who were H. pylori positive, and in 19 patients (100%) in whom H. pylori had been eradicated previously. Serum PG level had no influence on the healing process. Among 15 patients with ulceration or ulcer scar with the lesion, ulcer healing was observed in nine patients (60%), which was significantly low. CONCLUSIONS: Infection status of H. pylori and the extent of gastric atrophy do not affect ulcer healing after ESD. Preoperative existence of fibrotic change in the submucosal layer may delay the healing process.

Female↗
PubMed2006

External beam radiotherapy to treat intra- and extra-hepatic dissemination of hepatocellular carcinoma after radiofrequency thermal ablation.

BACKGROUND: Radiofrequency ablation (RFA) is an alternative to percutaneous ethanol injection therapy (PEIT) for single non-surgical hepatocellular carcinoma. However, the risk of seeding along the needle track has been reported. METHODS: Seven patients presenting with neoplastic seeding after RFA or PEIT were treated with external beam radiotherapy using conventional fractionation. All patients underwent irradiation with a total dose in the range of 44-61 Gy (median and mode value: 50 Gy). RESULTS: An objective response to treatment was achieved in six of seven patients (86%). A complete response was obtained in two patients (29%). The median survival time was 14.7 months and the actuarial 1- and 2-year survivals were 67% and 50%, respectively. CONCLUSIONS: The response to treatment was relatively good without serious complications. Seeding from hepatocellular carcinoma is sensitive to external beam radiotherapy. It is useful in the treatment of these patients with 50 Gy in 25 fractions.

Aged↗
PubMed2006

Sustained viral response prolonged survival of patients with C-viral hepatocellular carcinoma.

BACKGROUND: We conducted this retrospective study to evaluate the position of interferon therapy in the curative treatment of hepatitis C virus-associated hepatocellular carcinoma (HCC). METHODS: We compared overall and recurrence-free survival rates between 191 patients who received interferon therapy before HCC development (15 with sustained virologic response (SVR)), 53 who received interferon therapy after HCC ablation (17 with SVR), and 399 HCC patients with Child-Pugh class A liver function who did not receive interferon (controls). RESULTS: The overall survival rate in the controls was 82.4%, 53.2%, and 28.3% at 3, 6, and 9 years, respectively, whereas that in patients who developed HCC after achieving SVR was 93.3%, 93.3%, and 93.3%; those with HCC after non-SVR, 87.8%, 56.5%, and 35.8%; SVR after HCC, 100%, 87.5%, and 59.7%; and non-SVR after HCC, 94.3%, 70.9%, and 53.2%. Cox proportional hazard regression analysis revealed that the risk of death was significantly reduced in patients with HCC after SVR and those with SVR after HCC, with a risk ratio of 0.124 (95% confidence interval (95% CI): 0.017-0.890, P = 0.0378) and 0.388 (95% CI: 0.169-0.887, P = 0.0250), respectively, compared with the controls. Improved survival was attributable mainly to sustained liver function among patients with SVR, and recurrence-free survival did not differ significantly. CONCLUSION: Interferon therapies before and after HCC development were both significantly associated with prolonged survival when SVR was achieved.

Aged↗
PubMed2006

Twenty-four weeks of interferon alpha-2b in combination with ribavirin for Japanese hepatitis C patients: sufficient treatment period for patients with genotype 2 but not for patients with genotype 1.

BACKGROUND: Hepatitis C virus (HCV) RNA titer and HCV genotype are two major determinants of the outcome of interferon (IFN) monotherapy. To clarify the usefulness of combination therapy with IFN and ribavirin in Japanese hepatitis C patients, we treated patients with a relatively high dose of IFN in combination with ribavirin for 24 weeks and examined the effects in relation to the viral parameters. METHODS: Two hundred and ninety-five patients were enrolled in the study. The patients received either 6 or 10 million units (MU) of interferon alpha-2b every day for 2 weeks and then three times a week for 22 weeks with a daily dose of either 600 or 800 mg of ribavirin. The treatment response and safety of this treatment were examined. RESULTS: The sustained virologic response (SVR) rates were 26.8% in genotype 1 and 76.5% in genotype 2 (P < 0.001), and 36.1% with the 6 MU group and 45.8% with the 10 MU group (P = 0.09). Multivariate analysis indicated that SVR was associated with genotype 2, HCV RNA <500 kilointernational unit/ml (kIU/ml), and HCV RNA undetectability at week 8 of treatment. CONCLUSION: Our current study showed that a 24-week course of IFN plus ribavirin combination therapy was effective with respect to virologic response in Japanese hepatitis C patients, particularly in patients with HCV genotype 2.

Adolescent↗