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M Ohta

Publications and source records attributed to M Ohta.

At least 19 recordsLinked to original sources
PubMed2006

Absence of tyrosine kinase mutations in Japanese colorectal cancer patients.

Tyrosine kinases, which are important regulators of intracellular signal-transduction pathways, have mutated forms that are often associated with oncogenesis and are attractive targets for therapeutic intervention. Recently, systematic mutational analyses of tyrosine kinases revealed that a minimum of 30% of colorectal cancer contain at least one mutation in the tyrosine kinases. To further explore these mutations, we examined all reported mutations of NTRK3, FES, KDR, EPHA3, NTRK2, JAK1, PDGFRA, EPHA7, EPHA8, ERBB4, FGFR1, MLK4 and GUCY2F genes in the 24 colorectal cancer cell lines. Unexpectedly, among 24 colorectal cancer cell lines, only two cell lines (LoVo and CaR1) harbored mutation C1408T (R470C) in MLK4 gene. The mutation rate was extremely low compared to that previously reported. Therefore, we analyzed mutations in 46 colorectal cancer samples resected from the same number of Japanese patients. Surprisingly, none of the 46 samples contained any of the mutations reported. Based on our study, we advise that a more comprehensive tyrosine kinase gene mutation assay is necessary in the future.

Aged↗
PubMed2006

Inclusion of the transcervical approach in video-assisted thoracoscopic extended thymectomy (VATET) for myasthenia gravis: a prospective trial.

BACKGROUND: Because evidence-based data regarding the quality of video-assisted thoracoscopic thymectomy for the treatment of myasthenia gravis are lacking, a prospective trial comparing three different operative approaches was conducted to evaluate their efficacy. METHODS: This prospective study enrolled 20 consecutive patients with nonthymomatous myasthenia gravis. A series of three approaches for bilateral video-assisted thoracoscopic extended thymectomy (VATET) using the anterior chest wall-lifting method (original), the original method with a flexed-neck position (modified), and the original method with a transcervical approach (final) were prospectively performed in each patient for quantitative and pathologic evaluation of the residual thymus after each approach. RESULTS: Complete VATET required 242 +/- 48 min, with the transcervical procedure requiring 23 +/- 12 min. After the modified method, the residual thymus in the cervical region was 1.5 cm in size and weighed 0.8 g (0.8% of the entire thymus), as compared with a size of 2.2 cm and a weight of 1.3 g (3.2%) after the original method. Each value is the result of comparison with the final method. Histopathologic studies showed residual tissue in the germinal center as well as Hassall's corpuscles in more than 70% of cases. CONCLUSION: The findings show that VATET without the transcervical approach could be an immunologically incomplete treatment for myasthenia gravis. Therefore, the transcervical approach should be included in VATET procedures to ensure radicality.

Adult↗
PubMed2006

Preoperative transcatheter arterial chemoembolization reduces long-term survival rate after hepatic resection for resectable hepatocellular carcinoma.

AIMS: To study the effect of preoperative transcatheter arterial chemoembolization (TACE) on long-term survival after hepatic resection for hepatocellular carcinoma (HCC), we conducted a comparative analysis in 235 HCC patients who underwent hepatic resection with a curative intent. METHODS: We compared clinicopathologic background, mortality, and survival rates after hepatic resection between those who underwent preoperative TACE (n=109) and those who did not (n=126). RESULTS: One hundred and two patients in the TACE group (93.6%) received TACE only once. The mean interval between TACE and hepatic resection was 33.1days. Patients in the TACE group were younger than those in the non-TACE group, and liver cirrhosis and non-anatomical hepatic resection were more prevalent in this group. The 5-year overall survival rate after hepatic resection was significantly lower in the TACE group (28.6%) than in the non-TACE group (50.6%), especially in patients without cirrhosis or with stage I or II tumor. There was no difference between the two groups in mortality or disease-free survival after hepatic resection. Multivariate analysis showed preoperative TACE, preoperative aspartate aminotransferase elevation, and microscopic portal invasion to be independent risk factors for a poor outcome after hepatic resection. CONCLUSIONS: Preoperative TACE should be avoided for patients with resectable HCC, especially for those without cirrhosis or with an early stage tumor.

Adult↗
PubMed2006

Laparoscopy-assisted right hepatic lobectomy using a wall-lifting procedure.

This article describes a new technique for performing a laparoscopy-assisted right hepatic lobectomy using a hanger wall-lifting procedure. The patient is placed in the left semi-lateral position. A cholecystectomy and hemi-hepatic vascular inflow control are then performed through a midline incision, through which the resected liver can be removed. Next, the right lower chest and right upper abdominal wall are lifted by two wires vertical to the abdominal wall. Two ports, a 5-mm port in right lateral abdomen for forceps and a 12-mm port just right of the umbilicus for the laparoscope, are inserted. The obtained view of the operative field in the right upper abdominal cavity is thus excellent. The laparoscopy-assisted mobilization of the right hepatic lobe is done with the assistance of a hand inserted through the midline incision, including a dissection of the hepato-renal ligament, the right triangular ligament, and the right coronary ligament. A parenchymal dissection is then performed using the Cavitron Ultrasonic Surgical Aspirator (CUSA) and the resected specimen is passed through the midline incision without any morcellation of the liver. This procedure can minimize the length of the wound, while avoiding the lethal complications associated with pneumoperitoneum.

Hepatectomy↗
PubMed2006

Absence of PIK3CA hotspot mutations in hepatocellular carcinoma in Japanese patients.

A recent study revealed that the p110alpha (PIK3CA), catalytic subunit of phosphatidylinositol 3-kinase (PI3K), is somatically mutated in many types of cancer. For example, PIK3CA is mutated in an estimated 35.6% of hepatocellular carcinoma (HCC) cases. To measure the frequency of PIK3CA hotspot mutations in Japanese HCC patients, exons 9 and 20 of the PIK3CA gene were sequenced in 47 clinical HCC samples. Contrary to expectations, no hotspot mutations were found any of the HCC samples. In addition, we found abnormally migrating waves near the end of exon 9 in the PCR chromatograms from 13 of the 47 samples. PCR amplification and subsequent cloning and sequencing revealed that these chromatograms contained two distinct sequences, the wild-type p110alpha sequence and a different sequence found on human chromosome 22q11.2, the Cat Eye Syndrome region, which contains a putative pseudogene of PIK3CA. These abnormally migrating waves were also found in noncancerous liver tissue, indicating that this was not a result of HCC-associated mutations. Therefore, it is likely that the percentage of hotspot mutations in the PIK3CA gene of Japanese HCC patients is lower than was previously reported.

Adult↗
PubMed2006

The hepatitis B virus X protein enhances AP-1 activation through interaction with Jab1.

Hepatitis B virus X protein (HBx) has many cellular functions and is a major factor in hepatitis and hepatocellular carcinoma caused by HBV infection. A proteomic approach was used to search for HBx-interacting proteins in order to elucidate the molecular mechanism of hepatocarcinogenesis. HBx was attached to myc and flag tags (MEF tags) and expressed in 293T cells; the protein complex formed within the cells was purified and characterized by mass spectrometry. COP9 signalosome (CSN) subunits 3 and 4 were subsequently identified as HBx-interacting proteins. In addition, CSN subunit 5, Jun activation domain-binding protein 1 (Jab1), was shown to be a novel cellular target of HBx. In vivo and in vitro interactions between HBx and Jab1 were confirmed by standard immunoprecipitation and GST pull-down assays. An analysis of HBx deletion constructs showed that amino acids 30-125 of HBx were responsible for binding to Jab1. Confocal laser microscopy demonstrated that HBx was mainly localized in the cytoplasm, while Jab1 was found mainly in the nucleus and partially in the cytoplasm, and that the two proteins colocalized in the cytoplasm. The cotransfection of HBx and Jab1 resulted in substantial activator protein 1 (AP-1) activation and knockdown of endogenous Jab1 attenuated AP-1 activation caused by HBx. In addition, the coexpression of HBx and Jab1 potentiated phosphorylation of JNK, leading to the subsequent phosphorylation of c-Jun, whereas the level of c-Jun and JNK phosphorylation induced by HBx was decreased in Jab1 knockdown cells. These results suggest that the interaction between HBx and Jab1 enhances HBx-mediated AP-1 activation.

COP9 Signalosome Complex↗
PubMed2006

Iron overload and antioxidative role of perivascular astrocytes in aceruloplasminemia.

Aceruloplasminemia (ACP) is an inherited disorder of iron metabolism caused by the lack of ceruloplasmin activity; the neuropathological hallmarks are excessive iron deposition, neuronal loss, bizarrely deformed astrocytes, and numerous 'grumose or foamy spheroid bodies (GFSBs)'. We histopathologically examined two autopsied ACP brains, and observed for the first time that GFSBs form in clusters at the ends of perivascular astrocytic foot processes. Both the deformed astrocytes and the GFSBs contained ferric iron and were intensely immunolabelled with antibodies against the antioxidant proteins ferritin and manganese superoxide dismutase (Mn SOD). Ceruloplasmin is largely produced by perivascular astrocytes in the central nervous system and exhibits a ferroxidase activity that inhibits iron-associated lipid peroxidation and hydroxyl radical formation; therefore, the lack of ceruloplasmin causes direct oxidative stress on astrocytes. The intense immunolabelling of ferritin and Mn SOD most likely reflects a defensive response to iron-mediated oxidative stress. This study suggests that astrocytes play key roles in iron trafficking and the detoxification of iron-mediated free radicals at the blood-brain barrier and in the parenchyma in ACP brain. The antioxidative ability of astrocytes is one of their essential neuroprotective effects, and the decompensation of this ability may lead to secondary neuronal cell death in ACP.

Antioxidants↗
PubMed2005

The retroperitoneum protects prosthetic graft material from intraperitoneal contamination: an experimental study.

OBJECTIVES: To evaluate the ability of the retroperitoneum to serve as a barrier, against bacterial contamination, between the peritoneal cavity to the retroperitoneal space. METHODS: Seventy rats had a small piece of knitted Dacron graft placed in the retroperitoneal space and 10(6)-10(9) colony forming unit (cfu) Enterococcus faecalis was injected into the peritoneal cavity. In half the retroperitoneal (RP) group, the retroperitoneum was preserved and in the remainder, the open peritoneal (OP) group, needle holes were created. Grafts were harvested after 1, 4, or 7 days and cultured for E. faecalis. A blood sample was collected from three rats in each group for culture before the graft was harvested. RESULTS: Graft infection did not develop in any rat injected with 10(6) or 10(7) cfu in the RP group, while seven out of the 10 graft cultures of the OP group grew E. faecalis (P = 0.003). In rats injected with 10(8) or 10(9) cfu, five out of the 10 graft cultures in the RP group and eight out of 10 in the OP group grew E. faecalis. All blood cultures were negative when the injected bacterial count was 10(7) cfu or less. One out of the three blood cultures was positive at 10(8) cfu, and all were positive at 10(9) cfu. CONCLUSIONS: These results suggest that an intact retroperitroneum acts as a protective barrier against intraperitoneal bacterial contamination, particularly when blood cultures are negative.

Animals↗
PubMed2005

Association of ghrelin receptor gene polymorphism with bulimia nervosa in a Japanese population.

Eating disorders (EDs) have a highly heterogeneous etiology and multiple genetic factors might contribute to their pathogenesis. Ghrelin, a novel growth hormone-releasing peptide, enhances appetite and increases food intake, and human ghrelin plasma levels are inversely correlated with body mass index. In the present study, we examined the 171T/C polymorphism of the ghrelin receptor (growth hormone secretagogue receptor, GHSR) gene in patients diagnosed with EDs, because the subjects having ghrelin gene polymorphism (Leu72Met) was not detected in a Japanese population, previously. In addition, beta3 adrenergic receptor gene polymorphism (Try64Arg) and cholecystokinin (CCK)-A receptor (R) gene polymorphism (-81A/G, -128G/T), which are both associated with obesity, were investigated. The subjects consisted of 228 Japanese patients with EDs [96 anorexia nervosa (AN), 116 bulimia nervosa (BN) and 16 not otherwise specified (NOS)]. The age- and gender-matched control group consisted of 284 unrelated Japanese subjects. The frequency of the CC type of the GHSR gene was significantly higher in BN subjects than in control subjects (chi(2) = 4.47, p = 0.035, odds ratio = 2.05, Bonferroni correction: p = 0.070), while the frequency in AN subjects was not different from that in controls. The distribution of neither beta3 adrenergic receptor gene nor CCK-AR polymorphism differed between EDs and control subjects. Therefore, the CC type of GHSR gene polymorphism (171T/C) is a risk factor for BN, but not for AN.

Adult↗
PubMed2005

Increased serum resistin levels in patients with type 2 diabetes are not linked with markers of insulin resistance and adiposity.

The role of resistin in human biology remains uncertain. We measured serum resistin levels in Japanese patients with (n=111) and without (n=98) type 2 diabetes mellitus and investigated the significance of this hormone in the pathophysiology of diabetes. The levels of serum adiponectin and leptin were also measured. Resistin levels were increased significantly in patients with type 2 diabetes compared with non-diabetic subjects (24.7+/-2.6 vs. 15.0+/-1.2 ng/ml, p=0.0013). However, there was no correlation in either patient group between serum resistin levels and markers of insulin resistance, obesity or hyperlipidaemia. These results were in direct contrast to the data of leptin or adiponectin, both of which were closely related to these clinical markers of diabetes. Multivariate regression analysis on the combined data of the two groups demonstrated that the presence of diabetes and HDL cholesterol levels were significant predictors of serum resistin levels (diabetes: beta=0.159, p=0.035; HDL: beta=-0.172, p=0.039). No correlation was observed between C-reactive protein and resistin adjusted for BMI. Taken together, these findings demonstrate that serum resistin levels are increased in patients with type 2 diabetes, but this increase is not linked to markers of insulin resistance or adiposity. Further studies are necessary to elucidate the significance of serum resistin concentration in human pathophysiology.

Adiponectin↗
PubMed2005

A randomized phase III trial of adjuvant chemotherapy with UFT for completely resected pathological stage I non-small-cell lung cancer: the West Japan Study Group for Lung Cancer Surgery (WJSG)--the 4th study.

PURPOSE: To examine the efficacy of UFT, an oral 5-fluorouracil derivative agent, as post-operative adjuvant therapy for pathologic (p-) stage I non-small-cell lung cancer (NSCLC), because a previous randomized study had suggested it was efficacious for early-stage NSCLC patients. PATIENTS AND METHODS: Patients with completely resected p-stage I, adenocarcinoma or squamous cell carcinoma were eligible. A total of 332 patients were randomized to the surgery-alone group (control group) and the treatment group (UFT 400 mg/m(2) for 1 year after surgery, UFT group) after stratification by the histologic types. RESULTS: For all patients, the 5- and 8-year survival rates for the UFT group were 82.2% and 73.0%, and those for the control group were 75.9% and 61.2%, respectively; no statistically significant improvement of survival was achieved by UFT administration (P=0.105). For Ad patients, the 5- and 8-year survival rates of the UFT group (n=120) were 85.2% and 79.5%, respectively, which seemed better than those of the control group (n=121) (79.2% and 64.0%, respectively; P=0.081). For squamous cell carcinoma patients, there was also no difference in survival between the control group (n=48) and the UFT group (n=43) (P=0.762). For all pT1 patients, the 5- and 8-year survival rates of the UFT group were 83.6% and 82.1%, respectively, significantly better than those of the control group (77.9% and 57.6%, respectively, P=0.036); UFT was not significantly effective for pT2 patients. For pT1 adenocarcinoma patients, UFT administration markedly improved the survival (P=0.011). CONCLUSION: Post-operative UFT administration did not significantly improve post-operative survival of p-stage I NSCLC patients. Subset analyses suggested that UFT might be effective in pT1N0M0 adenocarcinoma patients.

Adenocarcinoma↗
PubMed2005

[Left-sided adult Bochdalek hernia with right lung cancer; report of a case].

Bochdalek hernia is a common congenital anomaly in neonatal patients with risky respiratory distress and high mortarity, but can be seen in adults. A case of left-sided adult Bochdalek hernia with right lung cancer is reported. A 71-year-old female had been performed radition therapy for lung cancer in the right lower lobe. She was admitted to our hospital due to advanced lung cancer and pneumonia. On the 7th day after admission, she felt dyspnea and abdominal distention due to herniation of the stomach through the posterolateral defect of the diaphragma into the left hemithorax. Her condition did not allow us a radical surgery of Bochdalek hernia, so that we performed a palliative surgery, that is reduction of the stomach and gastrostomy. After surgery, her respiratory distress was lightened and she came to be able to ingest. She was less uncomfortable until she died due to progression of the lung cancer.

Aged↗
PubMed2004

Linkage and association of febrile seizures to the IMPA2 gene on human chromosome 18.

BACKGROUND: Febrile seizures (FSs) are the most common form of childhood seizures, and genetic factors play a role in susceptibility to FS. OBJECTIVE: To identify novel loci and genes associated with susceptibility to FS. METHODS: Study participants were the FS probands and family members of 59 Japanese nuclear families (223 members including 112 affected children). Forty-eight of these families had at least two affected children for which genome-wide linkage screening was carried out. The Genehunter software was used to perform nonparametric multipoint linkage analysis. Mutational and association analyses were conducted in all 59 Japanese FS families. RESULTS: Genotyping data of 407 microsatellite markers suggested linkage of FSs to chromosome 18p11.2 (non-parametric linkage score = 3.68, p = 0.0001). This region includes the IMPA2 gene, which encodes myo-inositol monophosphatase (IMPase) 2. In the phosphatidylinositol-signaling pathway, IMPase is inhibited by lithium, which has a proconvulsant effect, and is stimulated by carbamazepine, an anticonvulsant. A systematic search was performed for mutations in IMPA2 in 24 unrelated randomly selected Japanese FS patients; seven variants were detected. Haplotype analysis revealed an association of a common haplotype in IMPA2 with FSs (p = 0.0009). CONCLUSION: The authors found a novel locus on chromosome 18p11.2 for febrile seizures (FSs). IMPA2 is likely to be an FS susceptibility gene.

Bipolar Disorder↗
PubMed2004

Complete versus assisted thoracoscopic approach: a prospective randomized trial comparing a variety of video-assisted thoracoscopic lobectomy techniques.

BACKGROUND: Video-assisted thoracoscopic surgery (VATS) lobectomy does not represent a unified approach, but rather a spectrum of operative techniques ranging from a complete endoscopic thoracotomy to a minithoracotomy. A prospective randomized trial was conducted to compare the differences in these techniques and their results to determine the best of VATS lobectomy for lung cancer. METHODS: This study randomized 39 consecutive patients with clinical stage I lung cancer to undergo either a complete (C-VATS, n = 20) or an assisted (A-VATS, n = 19) VATS approach for pulmonary lobectomy. RESULTS: The operating time was longer (p = 0.002) and blood loss was less (p = 0.004) with C-VATS than with A-VATS. Although there was no significant difference in analgesic use or duration of thoracic drainage between the groups, a shorter hospitalization was observed after C-VATS. Serum peak levels of postoperative inflammatory markers (white blood cell count, C-reactive protein, creatine phosphokinase) were lower with C-VATS and an earlier return to normalization than with A-VATS. CONCLUSION: Various differences exist among the VATS lobectomy techniques, and complete VATS lobectomy as a purely endoscopic surgery may be technically feasible and a satisfactory alternative to the conventional procedure for stage I lung cancer.

Aged↗
PubMed2004

Gallbladder wall thickening associated with infectious mononucleosis.

Acute infectious mononucleosis is a typical self-limited lymphoproliferative illness characterized by fever, tonsillar pharyngitis, and lymphadenopathy in adolescents and young adults. Thickening of the gallbladder wall is rarely observed. We report a case of infectious mononucleosis in which marked thickening of the gallbladder wall was detected by ultrasonography and computed tomography.

Adolescent↗
PubMed2004

Redox state-dependent and sorbitol accumulation-independent diabetic albuminuria in mice with transgene-derived human aldose reductase and sorbitol dehydrogenase deficiency.

AIMS/HYPOTHESIS: We investigated the role played by sorbitol accumulation in the kidney in the development of diabetic albuminuria. METHODS: We created mice ( hAR-Tg:SDH null) with transgene-derived human aldose reductase and sorbitol dehydrogenase (SDH) deficiency, and analysed (i). the contribution of accumulated sorbitol to urinary albumin excretion rate, and (ii). the effect of the aldose reductase inhibitor, epalrestat, on the diabetic redox state, including decreased renal reduced glutathione concentrations or increased lactate to pyruvate ratios in the diabetic kidney. RESULTS: Compared to littermates, non-diabetic transgenic mice had a 2.6-fold increase in aldose reductase mRNA. In a diabetic group, aldose reductase mRNA in hAR-Tg mice was 2.7-fold higher than in littermates. In the diabetic and non-diabetic groups, hAR-Tg:SDH null mice had the highest sorbitol content among all four genetic types including hAR-Tg:SDH null, SDH null, hAR-Tg and littermates. The urinary albumin excretion rate in non-diabetic groups was similar in the four genetic types of mouse. In diabetic groups it was greater than in non-diabetic groups, but did not correlate with the sorbitol content among the four genetic types of mouse. When aldose reductase inhibitor and streptozotocin were given simultaneously at 6 weeks of age, epalrestat prevented diabetic increases in urinary albumin excretion rate and completely prevented diabetic decreases in reduced glutathione concentrations and diabetic increases in lactate to pyruvate ratios, even in the presence of transgenic aldose reductase. CONCLUSIONS/INTERPRETATION: The degree of diabetic albuminuria in genetically modified mice is dependent on the redox state and independent of polyol accumulation; aldose reductase inhibitor can prevent diabetic albuminuria by normalising diabetic redox changes.

Albuminuria↗