Search PubMed⌕ Search

Biomedical subjects

T Ochiai

Publications and source records attributed to T Ochiai.

At least 19 recordsLinked to original sources
PubMed2007

Concurrent chemoradiation for patients with squamous cell carcinoma of the cervical esophagus.

Little is known concerning the role of concurrent chemoradiation (CCRT) in the management of carcinoma of the cervical esophagus. We retrospectively evaluated our treatment approach for patients with cervical esophageal cancer with special emphasis on CCRT with or without surgery. Medical records of 21 consecutive patients with cervical esophageal carcinoma treated mainly with CCRT (1997-2004) were reviewed, and factors that influenced patient survival were analyzed retrospectively. Nineteen received CCRT with cisplatin/5-fluorouracil and five underwent curative surgery. Two patients who were deemed unfit for CCRT received radiation therapy alone. All had three-dimensional treatment planning (median total dose, 40 Gy with surgery, 64 Gy without surgery). Of the 19 patients who received CCRT, 11 patients including five who underwent curative surgery achieved initial local control. Neither of the two patients who received radiation therapy alone achieved local control. Among 19 patients who underwent CCRT, 9/11 with T1-3 grade tumors achieved initial local control, but only 2/8 patients with T4 tumors (P = 0.011, chi(2) test) achieved initial local control. No patient without initial local control survived > 20 months compared with 2-year and 5-year survival rates of 60% and 40% in those who achieved initial local control (P = 0.038). No patient with T4 tumors survived > 18 months, whereas 2- and 5-year survival rates were 62% and 41%, respectively, in those with T1-3 tumors (P = 0.006). The significant effect of T-classification on survival was maintained when analyzed among 19 patients who received CCRT. CCRT shows promise for cervical esophageal carcinoma. T-classification and initial local control had significant impact on survival.

Aged↗
PubMed2006

Plasminogen activator inhibitor-1 aids nerve growth factor-induced differentiation and survival of pheochromocytoma cells by activating both the extracellular signal-regulated kinase and c-Jun pathways.

Astrocytes are thought to be critical to neurons' surviving damage caused by ischemic stroke or other injury. Plasminogen activator inhibitor-1 is one of the active soluble factors released by astrocytes and regulates plasminogen activator-plasmin proteolytic sequence in the CNS as a serpin. In this study, we show that plasminogen activator inhibitor-1 can promote neurite outgrowth and survival of rat pheochromocytoma cells in serum-deprived conditions, and that this neuroprotective activity is correlated with enhanced activation of both extracellular signal-regulated kinases following a direct phosphorylation of nerve growth factor receptor, Trk A, and of c-Jun. Our results suggest that plasminogen activator inhibitor-1 can act as a neurotrophic factor, protecting neurons from serum deprivation-induced neuron death not only by compensating for nerve growth factor functions, but also by activating the c-Jun/activating protein-1 pathway.

Animals↗
PubMed2006

Enhancement of chemosensitivity toward peplomycin by calpastatin-stabilized NF-kappaB p65 in esophageal carcinoma cells: possible involvement of Fas/Fas-L synergism.

Chemosensitivity to anticancer drugs was compared between two human esophageal carcinoma cell lines, T.Tn and YES-6 cells. T.Tn cells were more resistant than YES-6 cells to peplomycin (PEP) but not to the other anticancer drugs such as camptothecin, mitomycin C and cytosine arabinoside. Western blot analysis showed higher expression levels of m-calpain and activated mu-calpain in T.Tn cells than in YES-6 cells. On the other hand, YES-6 cells showed a high expression level of calpastatin, which is a calpain-specific endogenous inhibitor. To investigate whether calpain activity was involved in the chemosensitivity, T.Tn cells were transfected with calpastatin cDNA in an inducible expression vector. The induction of calpastatin was accompanied by increased chemosensitivity to PEP. The increases in calpastatin levels were followed by serial increases in the expression levels of NF-kappaB p65 and Fas. Since purified m- or mu-calpain degraded NF-kappaB p65 in vitro, it is possible that calpastatin suppressed calpain-mediated degradation of NF-kappaB p65. Fas ligand (Fas-L) protein levels increased after treatment of the parental T.Tn and calpastatin-transfected cells with PEP, suggesting the synergism between calpastatin-induced Fas and PEP-induced Fas-L. These results suggest that calpain/calpastatin expression levels are effective markers for predicting the sensitivity of human esophageal carcinoma cells to PEP.

Antibiotics, Antineoplastic↗
PubMed2006

Non-cavernomatous superior mesenteric thrombosis successfully recanalized with interventional radiological procedures carried out with a combination transmesenteric and transjugular approaches.

This is the study of a 52-year-old man with oesophageal, rectal and anal varices caused by portal hypertension with complete obstruction of the superior mesenteric vein. Treatment by two sessions of interventional radiological procedures was successful. The first was a catheter-directed thrombolysis using the transmesenteric approach. The second was percutaneous transluminal angioplasty and stent implantation for the obstructed segment of the superior mesenteric vein and the creation of a transjugular intrahepatic portosystemic shunt. In the second session, devices were advanced over a guidewire inserted from the right jugular vein and pulled out of the ileocolic vein using the pull-through technique.

Angioplasty, Balloon↗
PubMed2005

The role of log-normal dynamics in the evolution of biochemical pathways.

The study of the scale-free topology in non-biological and biological networks and the dynamics that can explain this fascinating property of complex systems have captured the attention of the scientific community in the last years. Here, we analyze the biochemical pathways of three organisms (Methanococcus jannaschii, Escherichia coli, Saccharomyces cerevisiae) which are representatives of the main kingdoms Archaea, Bacteria and Eukaryotes during the course of the biological evolution. We can consider two complementary representations of the biochemical pathways: the enzymes network and the chemical compounds network. In this article, we propose a stochastic model that explains that the scale-free topology with exponent in the vicinity of gamma approximately 3/2 found across these three organisms is governed by the log-normal dynamics in the evolution of the enzymes network. Precisely, the fluctuations of the connectivity degree of enzymes in the biochemical pathways between evolutionary distant organisms follow the same conserved dynamical principle, which in the end is the origin of the stationary scale-free distribution observed among species, from Archaea to Eukaryotes. In particular, the log-normal dynamics guarantees the conservation of the scale-free distribution in evolving networks. Furthermore, the log-normal dynamics also gives a possible explanation for the restricted range of observed exponents gamma in the scale-free networks (i.e., gamma > or = 3/2). Finally, our model is also applied to the chemical compounds network of biochemical pathways and the Internet network.

Biological Evolution↗
PubMed2005

Prospective randomized study of open versus laparoscopy-assisted distal gastrectomy with extraperigastric lymph node dissection for early gastric cancer.

BACKGROUND: Laparoscopy-assisted surgery with extraperigastric lymph node dissection for gastric cancers has been described, but the clinical benefits of these surgeries still are unclear. Short-term clinical outcomes were compared between laparoscopy-assisted distal gastrectomy (LADG) and conventional open distal gastrectomy (ODG) for early gastric cancer in a prospective randomized fashion. METHODS: For this study, 28 patients with early gastric cancers in the lower half of the stomach were randomly assigned to either LADG (n = 4) or ODG (n = 14). Postoperative pain, levels of acute inflammatory responses, and pathologic evaluation of the operative specimens were compared. RESULTS: The LADG group required a significantly shorter period of postoperative epidural anesthesia, showed significantly lower levels of serum interleukin-6 and C-reactive protein, and had no major postsurgery complications. Pathologic examinations showed that surgery was equally radical in the two groups. CONCLUSION: The findings show that LADG with extraperigastric lymph node dissection is a safe and less invasive alternative to the open procedure.

Aged↗
PubMed2005

Differentiation of the radiation-induced necrosis and tumor recurrence after gamma knife radiosurgery for brain metastases: importance of multi-voxel proton MRS.

Comparative analysis of the diagnostic accuracy of FDG PET, single-voxel, and multi-voxel proton MRS for differentiation between radiation-induced necrosis and tumor recurrence was done in 9 patients with brain metastases treated by gamma knife radiosurgery. In all cases enlargement of the lesion and increase of the perilesional edema were demonstrated by MRI on average 10.6+/-2.6 months after initial treatment. Radiation-induced necrosis was identified in 5 patients (histologically in 2, clinically in 3). In one of these a false positive result of FDG PET was observed, whereas data of proton MRS were always correct. The diagnosis of tumor recurrence was established in 4 patients (histologically in 3, clinically in 1). Among these both FDG PET and single-voxel proton MRS showed false negative results (each method twice), whereas multi-voxel proton MRS always permitted us to establish the correct diagnosis. The present study demonstrates the higher diagnostic accuracy of multi-voxel proton MRS, in comparison with single-voxel proton MRS and FDG PET, for the differentiation of the radiation-induced necrosis and tumor recurrence. Its use is especially important in mixed lesions with co-existence of both post-irradiation changes and viable neoplasm. Monitoring of the treatment response by serial multi-voxel proton MRS seems to be reasonable during follow-up of patients with brain metastases after radiosurgery.

Abnormalities, Radiation-Induced↗
PubMed2005

Dapsone suppresses human neutrophil superoxide production and elastase release in a calcium-dependent manner.

BACKGROUND: Dapsone (4,4'-diaminodiphenyl sulphone) is a powerful therapeutic tool in many skin diseases including neutrophilic dermatoses. The drug has an outstanding therapeutic efficacy against many skin diseases characterized by neutrophil-rich infiltrates; however, mechanisms of its action are poorly understood. OBJECTIVES: We investigated the effects of dapsone on respiratory and secretory functions of human neutrophils triggered by the chemotactic peptide N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP), the physiological agonist C5a, and phorbol myristate acetate (PMA). METHODS: Human neutrophils were isolated from venous blood obtained from healthy donors. We detected extracellular production of superoxide (O(2) (-)) by cytochrome C reduction assay, and intracellular production of O(2) (-) by flow cytometry. Neutrophil elastase release was measured by the cleavage of the specific elastase substrate N-methoxysuccinyl-Ala-Ala-Pro-Val-p-nitroanilide. Measurement of cytosolic free calcium concentration was performed using the calcium-reactive fluorescence probe, Fluo-3. RESULTS: Dapsone suppressed intra- and extracellular production of O(2) (-) and elastase release triggered by fMLP and C5a, but not by PMA. Both fMLP and C5a signalled the above pathways by inducing calcium influx, but PMA functions bypassed calcium influx. Dapsone was capable of antagonizing the induction of calcium influx. CONCLUSIONS: These findings suggest that one mechanism of the anti-inflammatory action of dapsone is inhibition of calcium-dependent functions of neutrophils including release of tissue-damaging oxidants and proteases in the affected skin.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2005

A case of bullous pemphigoid associated with autoantibodies targeting antigenic sites other than the NC16a domain of BP180.

Bullous pemphigoid (BP) is associated with autoantibodies to the 180-kDa BP antigen (BP180), and the antigenic site exists on noncollagenous 16a (NC16a) domain of BP180. We now report a male BP patient whose IgG autoantibodies did not react against the NC16a domain of BP180 by either immunoblotting or ELISA, whereas they did react with BP180 extracted from normal human keratinocytes. Anti-BP180 cicatricial pemphigoid was ruled out due to the lack of conjunctival mucosal involvement and the absence of scarring in the oral cavity. Our findings indicate that there is an antigenic reactive region other than NC16a on the extracellular domain of BP180. There have been few reports describing detailed clinical features of BP caused by autoantibodies targeting antigenic sites other than the NC16a domain. We conclude that it is difficult to differentiate their clinical features from those associated with autoantibodies targeting the NC16a domain of BP180.

Autoantibodies↗
PubMed2005

Overexpression of glucose transporter 1 in esophageal squamous cell carcinomas: a marker for poor prognosis.

SUMMARY: Recently, Glut1 (human erythrocyte glucose transporter) expression has been demonstrated in various tumors. The aim of this study is to evaluate the prognostic utility of Glut1 expression in esophageal carcinomas. We studied Glut1 expression by immunohistochemistry of paraffin sections from 63 esophageal squamous cell carcinomas. All 63 carcinomas expressed Glut1. The mean percentage of positively stained tumor cells was 77.8% (median, 84.7%). There were two staining patterns in positive cells: 'strongly positive' and 'weakly positive'. The percentage of 'strongly positive' cells (%Glut1-SP) ranged from 0% to 95.6% (mean, 32.3%; median, 27.4%). The 5-year survival rate for patients with a high %Glut1-SP (> 30%) was significantly lower than that for patients with a low %Glut1-SP (< 30%) (P < 0.01). Statistical analysis revealed that the relative risk of death for patients with high %Glut1-SP was 2.02 times that for patients with low %Glut1-SP (P = 0.064), suggesting a possible independent predictive value for %Glut1-SP.

Adult↗
PubMed2005

Neoadjuvant chemoradiotherapy followed by esophagectomy for initially resectable squamous cell carcinoma of the esophagus with multiple lymph node metastasis.

Neoadjuvant chemoradiotherapy (CRT) was expected to improve surgical curability and prognosis for advanced esophageal cancer. However, the clinical efficacy of neoadjuvant CRT followed by esophagectomy with three-field lymphadenectomy (3FL) for initially resectable esophageal squamous cell carcinoma (SCC) remains unclear. Since 1998, we have defined the status of metastases to five or more nodes, or nodal metastases present in all three fields as multiple lymph node metastasis, which was previously shown to be associated with poor prognosis. Between 1998 and 2002, 83 patients with initially resectable esophageal SCC were prospectively allocated into two groups, according to the clinical status of nodal metastasis. Nineteen patients clinically accompanied by multiple lymph node metastasis initially underwent neoadjuvant CRT followed by curative esophagectomy with 3FL (CRT group). The other 64 patients clinically without multiple lymph node metastasis immediately received curative esophagectomy with 3FL (control group). Although the overall morbidity rate was significantly higher in the CRT group, no in-hospital death occurred in either group. Patients without pathologic multiple lymph node metastasis in the CRT group showed a significantly better disease-free survival rate than either patients pathologically with multiple lymph node metastasis in the control group or those in the CRT group. However, the differences in the overall survival rate among the groups were not significant. Thus, the significant survival benefit by neoadjuvant CRT in addition to esophagectomy with 3FL was not confirmed, although it may have been advantageous, without increase in mortality, to at least some patients who responded well to neoadjuvant CRT. Therefore, neoadjuvant CRT can be an initial treatment of choice for resectable esophageal SCC clinically with multiple lymph node metastasis. The prediction of response to CRT and the development of alternative treatment for hematogenous recurrence could achieve a further survival benefit of this trimodality treatment.

Adult↗
PubMed2004

Hemodynamics of intrahepatic cholangiocarcinoma: evaluation with single-level dynamic CT during hepatic arteriography.

BACKGROUND: We determined the radiologic characteristics of intrahepatic cholangicarcinoma (ICC) on single-level dynamic computed tomography during hepatic arteriography (CTHA) and assessed the hemodynamics of the tumor. METHODS: Eleven patients with pathologically confirmed ICC underwent single-level dynamic CTHA. After placing the catheter tip in the proper hepatic artery and running a 30-s continuous scan, scanning was performed every 15 or 30 s for 120 s. The change of contrast-enhancement pattern of the ICCs were interpreted retrospectively. RESULTS: The pattern of enhancement was classified into two types: vascular and hypovascular. In the vascular type, the contrast enhancement gradually spread from each intratum oral artery and became mottled. It changed from a mottled and hypoattenuated pattern to an even and hyperattenuated appearance in comparison with the adjacent liver approximately 120 s after the injection of contrast agent. In the hypovascular type, the tumor was barely enhanced and remained hypoattenuated compared with the adjacent liver at 120 s after the beginning of the injection. The 11 ICCs were classified into eight vascular types and three hypovascular types. Intratumoral arteries were visualized in nine tumors: eight vascular types and one hypovascular type. CONCLUSION: The contrast-enhancement pattern of ICC on single-level dynamic CTHA is related to the intratumoral artery.

Aged↗
PubMed2004

Substantial reduction of critical current for magnetization switching in an exchange-biased spin valve.

Great interest in current-induced magnetic excitation and switching in a magnetic nanopillar has been caused by the theoretical predictions of these phenomena. The concept of using a spin-polarized current to switch the magnetization orientation of a magnetic layer provides a possible way to realize future 'current-driven' devices: in such devices, direct switching of the magnetic memory bits would be produced by a local current application, instead of by a magnetic field generated by attached wires. Until now, all the reported work on current-induced magnetization switching has been concentrated on a simple ferromagnet/Cu/ferromagnet trilayer. Here we report the observation of current-induced magnetization switching in exchange-biased spin valves (ESPVs) at room temperature. The ESPVs clearly show current-induced magnetization switching behaviour under a sweeping direct current with a very high density. We show that insertion of a ruthenium layer between an ESPV nanopillar and the top electrode effectively decreases the critical current density from about 10(8) to 10(7) A cm(-2). In a well-designed 'antisymmetric' ESPV structure, this critical current density can be further reduced to 2 x 10(6) A cm(-2). We believe that the substantial reduction of critical current could make it possible for current-induced magnetization switching to be directly applied in spintronic devices, such as magnetic random-access memory.

Journal Article↗
PubMed2004

Effective reduction of critical current for current-induced magnetization switching by a Ru layer insertion in an exchange-biased spin valve.

Recently, it has been predicted that a spin-polarized electrical current perpendicular to plane directly flowing through a magnetic element can induce magnetization switching through spin-momentum transfer. In this Letter, the first observation of current-induced magnetization switching (CIMS) in exchange-biased spin valves (ESPVs) at room temperature is reported. The ESPVs show the CIMS behavior under a sweeping dc current with a very high critical current density. It is demonstrated that a thin ruthenium (Ru) layer inserted between a free layer and a top electrode effectively reduces the critical current densities for the CIMS. An "inverse" CIMS behavior is also observed when the thickness of the free layer increases.

Journal Article↗
PubMed2004

A framework to study the cortical folding patterns.

This paper describes a decade-long research program focused on the variability of the cortical folding patterns. The program has developed a framework of using artificial neuroanatomists that are trained to identify sulci from a database. The framework relies on a renormalization of the brain warping problem, which consists in matching the cortices at the scale of the folds. Another component of the program is the search for the alphabet of the folding patterns, namely, a list of indivisible elementary sulci. The search relies on the study of the cortical folding process using antenatal imaging and on backward simulations of morphogenesis aimed at revealing traces of the embryologic dimples in the mature cortical surface. The importance of sulcal-based morphometry is illustrated by a simple study of the correlates of handedness on asymmetry indices. The study shows for instance that the central sulcus is larger in the dominant hemisphere.

Brain Mapping↗
PubMed2004

The effect of haematopoietic stem cell transplant on papules with 'pebbly' appearance in Hunter's syndrome.

BACKGROUND: Hunter's syndrome is associated with several cutaneous findings. For instance, papules with 'pebbly' appearance are a specific marker for the disease. However, it remains uncertain whether they disappear after haematopoietic stem cell transplant (HSCT). OBJECTIVES: To investigate the papules with 'pebbly' appearance before and after HSCT in infants with Hunter's syndrome, and to clarify the effect of HSCT on papules. PATIENTS: We observed five Japanese boys with Hunter's syndrome who had received HSCT at 4-11 years of age. RESULTS: The post-HSCT physical examinations revealed that papules disappeared completely within 35 days after the transplant with progressive reduction of cutaneous tightness in all the patients. Histochemical findings showed that papules contained a large amount of hyaluronic acid in the extracellular materials of the dermis and sulphated acid mucopolysaccharides in dermal fibroblasts before HSCT. CONCLUSIONS: These results suggest that papules with a 'pebbly' appearance fade away through the digestion of a large amount of hyaluronic acid in cutaneous tissues by normal tissue histiocytes or enzymes of donor origin at an early stage after HSCT.

Child↗
PubMed2004

COX-2+ myofibroblasts may play a key role in marked stromal fibrosis in strictured colorectal carcinomas.

AIMS: To elucidate the mechanism of marked stromal fibrosis in strictured colorectal carcinomas (SC) that cause complete ileus. METHODS AND RESULTS: Sixteen cases of SC and 29 cases of non-strictured colorectal carcinoma (NSC) were studied. These carcinomas showed similar clinicopathological features except for bowel stricture. The stricture index (SI) showing the degree of bowel stricture was 59.8 +/- 12.1% in SC versus 20.8 +/- 24.6% in NSC (P < 0.001). The fibrosis index (FI), defined to reflect the extent of stromal fibrosis, was 56.3 +/- 8.8% in SC versus 21.9 +/- 10.6% in NSC (P < 0.001). COX-2+ myofibroblasts were detected in 13 cases (81.3%) in SC versus eight cases (27.6%) in NSC (P < 0.01). The COX-2+ myofibroblast density was 276.7 +/- 181.1 cells/mm(2) in SC versus 26.6 +/- 52.7 cells/mm(2) in NSC (P < 0.001). When all cases were divided into two groups with and without COX-2+ myofibroblasts, the SI was 48.8 +/- 19.1% in those with COX-2+ myofibroblasts versus 24.8 +/- 29.3% in those with COX-2- myofibroblasts (P < 0.001). CONCLUSION: COX-2+ myofibroblasts may play an important role in extensive bowel stricture in colorectal carcinomas.

Colonoscopy↗