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Masahiro Ota

Publications and source records attributed to Masahiro Ota.

10 recordsLinked to original sources
PubMed2006

Immune responses of liver-infiltrating lymphocytes and peripheral blood mononuclear cells to hepatitis C virus core and NS3 antigens.

BACKGROUND AND AIM: Th1/Th2 cytokine balance is thought to play an important role in antiviral immunity and pathogenesis in viral infection. Ex vivo hepatitis C virus (HCV) antigen-specific T-cell responses were investigated. METHODS: Using enzyme-linked immunospot assay, HCV core and NS3 antigen-specific interferon-gamma-, interleukin-4- and interleukin-10-secreting cells were enumerated in peripheral blood mononuclear cells (PBMCs) from 30 chronic hepatitis C patients and 16 healthy controls, and in liver-infiltrating lymphocytes (LILs) from 17 of the 30 patients. RESULTS: IFN-gamma- and IL-10-secreting cells in response to stimulation with HCV core and NS3 antigen were detectable in both PBMCs and LILs from patients with chronic hepatitis C, although frequencies of the cytokine-secreting cells were much higher in LILs than PBMCs. They were not detectable in PBMCs of healthy controls except for IL-10-secreting cells in response to HCV NS3 antigen stimulation. IL-4-secreting cells were hardly detectable in both PBMC and LIL in both the patients and the healthy controls. Frequencies of HCV NS3 antigen-specific IFN-gamma- and IL-10-secreting cells in PBMCs correlated with those in LILs (rho=0.599, p=0.044 and rho=0.716, p=0.004, respectively). CONCLUSIONS: These data provide further evidence of the immunomodulatory role of the CD4(+)CD25(+) regulatory T lymphocytes in chronic HCV infection.

Journal Article↗
PubMed2006

Cancer and pulmonary embolism: thrombotic embolism, tumor embolism, and tumor invasion into a large vein.

BACKGROUND: The specific incidence of thrombotic pulmonary embolism (PE), tumor PE and tumor invasion into large veins according to tumor type and tumor site remains unclear. METHODS AND RESULTS: A total of 65,181 cancer patients were identified from 98,736 postmortem examinations. Thrombotic PE occurred in 2.32% of all cancer patients and comprised 88.6% of the total number of all PE events. The incidence of thrombotic PE was high in those with adenocarcinoma, leukemia and large cell carcinoma, and was low in those with hepatic cell carcinoma. The incidence of PE was high when tumor was present in hematogenous tissue, lungs, ovaries, pancreas and the biliary system, and was low when tumor was present in the liver. The incidence of tumor PE was high with large cell carcinoma, hepatic cell carcinoma and adenocarcinoma, and was also high when tumor was present in the lungs, ovaries, kidneys and liver. There was a significant correlation between the incidence of tumor PE and the incidence of tumor invasion into large veins. CONCLUSION: The incidence of thrombotic PE, tumor PE and tumor invasion into large veins varies significantly according to tumor histopathology and tumor site.

Adolescent↗
PubMed2005

Triggers of acute pulmonary thromboembolism developed in hospital, with focusing on toilet activities as triggering acts.

BACKGROUND: The recognition of the trigger which is the action leading to the occurrence of acute pulmonary thromboembolism (APTE) is important to perform early diagnosis and early management of APTE. METHODS AND RESULTS: The trigger of APTE in 138 patients who developed APTE in hospital was investigated. The triggers of APTE were specified in 57 patients. Approximately half of these patients developed APTE during toilet activities (defecation and micturition). Mortality of the patients with APTE associated with toilet activities was 33%. APTE associated with toilet activities was independently related to a recent major surgery, heart diseases and a recent angiography. CONCLUSIONS: Defecation and micturition would be common triggers of APTE after operation and angiography, especially in patients with cardiac dysfunction.

Acute Disease↗
PubMed2004

Pancreas head carcinoma with total fat replacement of the dorsal exocrine pancreas.

We report a case of pancreas head carcinoma associated with fat replacement of the body and tail. A 68-year-old man presented with obstructive jaundice and was admitted to our hospital. Ultrasonography and computed tomography showed pancreas head tumor with a neighboring cystic lesion and fatty replacement of parenchyma of the pancreas body and tail. By endoscopic retrograde pancreatography, abruption of the main pancreatic duct and the presence of an accessory duct were detected. After percutaneous transhepatic biliary drainage, pancreatoduodenectomy was successfully performed. At laparotomy, the pancreas head was easily dissected from the replaced fatty tissue of the body and tail without continuity of the ductal system or parenchyma. Microscopic examination revealed the existence of an infiltrating ductal adenocarcinoma and a neighboring. cyst in the pancreas head. The dorsal exocrine pancreas was completely replaced by the fat tissues, in which viable Langerhans' islets were scattered. The patient's postoperative course was uneventful, and exogenous insulin administration was unnecessary for the maintenance of normal blood sugar level. Acquired fat replacement of the body and tail of the pancreas is an uncommon disorder, mimicking congenital agenesis of the dorsal pancreas. Though the mechanism is controversial, obstruction of the main pancreatic duct by a cystic lesion or carcinoma in the pancreas head is a possible cause of fatty degeneration of the pancreatic parenchyma.

Adipose Tissue↗
PubMed2003

Association between antithrombotic treatments and prognosis of patients with acute pulmonary thromboembolism in Japan.

The utility of thrombolysis in patients with acute pulmonary thromboembolism (APTE) remains controversial, although anticoagulation therapy for APTE is well-established in Western countries. Nonetheless, large clinical trials of antithrombotic treatments for APTE have yet to be performed in Japan. In the present study, the association between antithrombotic treatments (thrombolysis and anticoagulation) and the clinical outcomes was retrospectively investigated in 225 APTE patients. In-hospital mortality was significantly lower in hemodynamically stable patients who received anticoagulation therapy than in those who received no adequate therapy (0% vs 33%). Thrombolysis in patients with or without cardiogenic shock failed to improve the in-hospital outcomes compared with those who received anticoagulation treatment (8% vs 3%). There was no significant difference in the bleeding rate between patients receiving thrombolysis and anticoagulation (3% vs 3%). These results indicate that anticoagulation could reduce the mortality of hemodynamically stable APTE patients and that the outcome after thrombolysis or anticoagulation treatment was similar. However, this study was limited because it was executed retrospectively. Further prospective randomized trials to investigate the efficacy of thrombolysis in Japan should be performed to completely address this issue.

Aged↗
PubMed2003

Full-blown Cushing's disease after an episode of pituitary apoplexy.

The present study reports a rare case of full-blown Cushing's disease several years after an episode of pituitary apoplexy. A 60 year-old woman complained of muscular weakness and generalized malaise. Ten years ago she had an episode of pituitary apoplexy. Diabetes mellitus was diagnosed at age 56, and thereafter she had been controlled her plasma glucose with diet therapy and oral hypoglycemic agents. She exhibited cushingoid feature of moon face and central obesity. Both plasma ACTH and serum cortisol levels were elevated to 170 pg/ml and 19.6 microg/dl, respectively. Dexamethasone suppression test showed that a large dose of 8 mg dexamethasone, but not a small dose of 2 mg, suppressed the pituitary-adrenocortical axis. CRH and methyrapone caused increases in plasma ACTH and serum cortisol levels. Brain T(1)-weighted magnetic resonance imaging depicted a low signal of pituitary tumor, which was not enhanced by gadolinium. The pituitary tumor was removed by transsphenoidal adenomectomy, and immunohistochemistry revealed an ACTH-producing adenoma. The evidence suggested the possibility that the two pituitary tumors with dormant period of several years were a recurrence of ACTH-producing tumors in the present patient.

Adenoma↗
PubMed2002

Prognostic significance of early diagnosis in acute pulmonary thromboembolism with circulatory failure.

Despite the advances in our understanding of venous thromboembolic disease, the prevalence of pulmonary thromboembolism (PTE) at autopsy has not changed over 3 decades. When patients survive long enough to have a diagnosis of massive PTE and start receiving treatment, the outlook is considered to be moderately good. However, the diagnosis is often difficult to obtain and is frequently missed. We hypothesize that mortality of acute PTE is reduced by early diagnosis. Eighty-five patients with acute PTE with circulatory failure who survived 1 h after the onset were divided into two groups: the early Dx group consisted of the patients whose disease was diagnosed as acute PTE within 24 h of the onset, and the Late Dx group included patients whose disease was not diagnosed within 24 h of onset, or died without clinical diagnosis between 1 and 24 h after the onset. Overall mortality was significantly low in the Early Dx group compared with that of the Late Dx group (21.6% vs 67.6%, P < 0.0001). Multiple logistic regression analysis demonstrated that a reduction in in-hospital mortality was associated with early diagnosis (odds ratio for in-hospital death, 0.094; 95% confidence interval, 0.03-0.33). The results of our study suggested that early diagnosis might favorably affect the in-hospital clinical outcome of hemodynamically unstable patients with acute PTE.

Adolescent↗
PubMed2002

Visualization of molecular dynamics by simulation.

The mechanism of formation of methane hydrate is investigated here at a molecular level. The key to whether or not methane hydrates can be formed is the stability of the hydrate structure. This paper deals with a computer simulation of methane hydrate type 1 formation by a molecular dynamics method and an accurate description of the crystal structure. Computer simulation results show that very stable type 1 methane hydrates can be formed below 275 K, in which 46 water and 8 methane molecules are contained in a single cubic unit cell of length 12.0 A. Above 275 K, the stability of the hydrates increasingly degrades, logarithmically as a power function, up to 300 K, with no stability at 350 K. Pressure, as a parameter of formation conditions, increases with temperature and becomes tremendously high at 350 K. Hydrates with various hydration numbers (at least one guest molecule in a small cage) have roughly the same degree of stability, but higher pressures are required for hydrates with fewer guest molecules. Empty hydrates dissolve above 275 K.

Journal Article↗