174 research outputs found

    "Probability Distribution and Option Pricing for Drawdown in a Stochastic Volatility Environment"

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    This paper studies the probability distribution and option pricing for drawdown in a stochastic volatility environment. Their analytical approximation formulas are derived by the application of a singular perturbation method (Fouque et al. [7]). The mathematical validity of the approximation is also proven. Then, numerical examples show that the instantaneous correlation between the asset value and the volatility state crucially affects the probability distribution and option prices for drawdown.

    Probability Distribution and Option Pricing for Drawdown in a Stochastic Volatility Environment ( Revised in May 2009; Electronic version of an article will be published in "International Journal of Theoretical and Applied Finance". [copyright world Scientific Publishing Company][http://www.worldscinet.com/ijtaf/] )

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    This paper studies the probability distribution and option pricing for drawdown in a stochastic volatility environment. Their analytical approximation formulas are derived by the application of a singular perturbation method (Fouque et al. [7]). The mathematical validity of the approximation is also proven. Then, numerical examples show that the instantaneous correlation between the asset value and the volatility state crucially affects the probability distribution and option prices for drawdown.

    ゲンパツ フメイ ガン ニオケル PET/CT ケンサ ノ ユウヨウセイ ニツイテ

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    We reported the utility of18F-FDG-PET/CT examination for patients with cancer of unknownprimary origin. Twenty six patients(13 men, 13 women, aged 27-91 years, mean 71)were examined.The indication for PET/CT examination was tumor maker elevation(14 patients), suspectedmetastatic tumor(14)and metastasis diagnosed histopathologically(3). Patients weretold not to eat for at least four hours and a PET/CT image was obtained one hour after theadministration of 3.7MBq/kg FDG. From April to August 2006, 33 patients diagnosed with a cancerof unknown primary origin were referred to our hospital for PET/CT examination from anoutside institution. Twenty six patients could be investigated for outcomes. Seventeen patientsshowed an abnormal accumulation, with 14 of the 17 having their primary regions detected histopathologicallyor clinically. For one patient, the abnormal accumulation could not be determined toshow the origin. For 2 patients, it was difficult to diagnose if these abnormal accumulationsshowed the primary region or not, but CT examinations were helpful for a diagnosis. Seven of the9 patients who showed no abnormal accumulation were treated conservatively and the primaryregion for their cancer could not be detected during the follow up study. In 21 of 26 patients, theseresults were useful to select an appropriate therapy to be applied or a relevant examination. Weconsidered PET/CT examination, where it is possible to scan the whole body at one time, was veryuseful to get both morphologic and metabolic information. PET/CT examination showed a highersensitivity for detecting abnormal lesions than other imaging modalities

    Dedifferentiated chondrosarcoma with leukocytosis and elevation of serum G-CSF. A case report

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    BACKGROUND: G-CSF is known to function as a hematopoietic growth factor and it is known to be responsible for leukocytosis. G-CSF-producing tumors associated with leukocytosis include various types of malignancies. CASE PRESENTATION: We report the case of a 72-year-old man with dedifferentiated chondrosarcoma characterized by dedifferentiated components of malignant fibrous histiocytoma- or osteosarcoma-like features in addition to conventional chondrosarcoma, arising from his pelvic bone. After hemipelvectomy, when local recurrence and metastasis were identified, leukocytosis appeared and an elevated level of serum granulocyte-colony-stimulating factor (G-CSF) was also recognized. The patient died of multiple organ failure 2 months after surgery. Autopsy specimens showed that the histological specimens of the recurrence and metastasis were dedifferentiated components, without any conventional chondrosarcoma components. G-CSF was expressed only in the dedifferentiated components, not in the chondrosarcoma components, immunohistochemically. CONCLUSION: This is the first report of chondrosarcoma, or any other primary bone tumor, with leukocytosis, probably stimulated by tumor-produced G-CSF from the dedifferentiated components

    CVIT expert consensus document on primary percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI) in 2018

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    While primary percutaneous coronary intervention (PCI) has significantly contributed to improve the mortality in patients with ST segment elevation myocardial infarction even in cardiogenic shock, primary PCI is a standard of care in most of Japanese institutions. Whereas there are high numbers of available facilities providing primary PCI in Japan, there are no clear guidelines focusing on procedural aspect of the standardized care. Whilst updated guidelines for the management of acute myocardial infarction were recently published by European Society of Cardiology, the following major changes are indicated; (1) radial access and drug-eluting stent over bare metal stent were recommended as Class I indication, and (2) complete revascularization before hospital discharge (either immediate or staged) is now considered as Class IIa recommendation. Although the primary PCI is consistently recommended in recent and previous guidelines, the device lag from Europe, the frequent usage of coronary imaging modalities in Japan, and the difference in available medical therapy or mechanical support may prevent direct application of European guidelines to Japanese population. The Task Force on Primary Percutaneous Coronary Intervention of the Japanese Association of Cardiovascular Intervention and Therapeutics (CVIT) has now proposed the expert consensus document for the management of acute myocardial infarction focusing on procedural aspect of primary PCI

    Troglitazone suppresses telomerase activity independently of PPARγ in estrogen-receptor negative breast cancer cells

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    <p>Abstract</p> <p>Background</p> <p>Breast cancer is one the highest causes of female cancer death worldwide. Many standard chemotherapeutic agents currently used to treat breast cancer are relatively non-specific and act on all rapidly dividing cells. In recent years, more specific targeted therapies have been introduced. It is known that telomerase is active in over 90% of breast cancer tumors but inactive in adjacent normal tissues. The prevalence of active telomerase in breast cancer patients makes telomerase an attractive therapeutic target. Recent evidence suggests that telomerase activity can be suppressed by peroxisome proliferator activated receptor gamma (PPARγ). However, its effect on telomerase regulation in breast cancer has not been investigated.</p> <p>Methods</p> <p>In this study, we investigated the effect of the PPARγ ligand, troglitazone, on telomerase activity in the MDA-MB-231 breast cancer cell line. Real time RT-PCR and telomerase activity assays were used to evaluate the effect of troglitazone. MDA-MB-231 cells had PPARγ expression silenced using shRNA interference.</p> <p>Results</p> <p>We demonstrated that troglitazone reduced the mRNA expression of hTERT and telomerase activity in the MDA-MB-231 breast cancer cell line. Troglitazone reduced telomerase activity even in the absence of PPARγ. In agreement with this result, we found no correlation between PPARγ and hTERT mRNA transcript levels in breast cancer patients. Statistical significance was determined using Pearson correlation and the paired Student's <it>t </it>test.</p> <p>Conclusions</p> <p>To our knowledge, this is the first time that the effect of troglitazone on telomerase activity in breast cancer cells has been investigated. Our data suggest that troglitazone may be used as an anti-telomerase agent; however, the mechanism underlying this inhibitory effect remains to be determined.</p

    CVIT expert consensus document on primary percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI) in 2018

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    While primary percutaneous coronary intervention (PCI) has significantly contributed to improve the mortality in patients with ST segment elevation myocardial infarction even in cardiogenic shock, primary PCI is a standard of care in most of Japanese institutions. Whereas there are high numbers of available facilities providing primary PCI in Japan, there are no clear guidelines focusing on procedural aspect of the standardized care. Whilst updated guidelines for the management of acute myocardial infarction were recently published by European Society of Cardiology, the following major changes are indicated; (1) radial access and drug-eluting stent over bare metal stent were recommended as Class I indication, and (2) complete revascularization before hospital discharge (either immediate or staged) is now considered as Class IIa recommendation. Although the primary PCI is consistently recommended in recent and previous guidelines, the device lag from Europe, the frequent usage of coronary imaging modalities in Japan, and the difference in available medical therapy or mechanical support may prevent direct application of European guidelines to Japanese population. The Task Force on Primary Percutaneous Coronary Intervention of the Japanese Association of Cardiovascular Intervention and Therapeutics (CVIT) has now proposed the expert consensus document for the management of acute myocardial infarction focusing on procedural aspect of primary PCI

    The Role of Inflammatory Mediators in the Pathogenesis of Otitis Media and Sequelae

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    This review deals with the characteristics of various inflammatory mediators identified in the middle ear during otitis media and in cholesteatoma. The role of each inflammatory mediator in the pathogenesis of otitis media and cholesteatoma has been discussed. Further, the relation of each inflammatory mediator to the pathophysiology of the middle and inner ear along with its mechanisms of pathological change has been described. The mechanisms of hearing loss including sensorineural hearing loss (SNHL) as a sequela of otitis media are also discussed. The passage of inflammatory mediators through the round window membrane into the scala tympani is indicated. In an experimental animal model, an application of cytokines and lipopolysaccharide (LPS), a bacterial toxin, on the round window membrane induced sensorineural hearing loss as identified through auditory brainstem response threshold shifts. An increase in permeability of the blood-labyrinth barrier (BLB) was observed following application of these inflammatory mediators and LPS. The leakage of the blood components into the lateral wall of the cochlea through an increase in BLB permeability appears to be related to the sensorineural hearing loss by hindering K+ recycling through the lateral wall disrupting the ion homeostasis of the endolymph. Further studies on the roles of various inflammatory mediators and bacterial toxins in inducing the sensorineumral hearing loss in otitis media should be pursued

    Effects of histone deacetylase inhibitor FR901228 on expression level of telomerase reverse transcriptase in oral cancer

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    We speculated whether or not the expression level of telomerase reverse transcriptase (hTERT) would be modulated by agents targeting epigenetics in oral cancer cell lines. Although hTERT is known to be targeted by epigenetic changes, it remains unclear how chemoagents targeting epigenetics work on hTERT transcription. In the present study, the epigenetic effects of histone deacetylase (HDAC) inhibitor FR901228 on hTERT transcription were analysed by RT-PCR in oral cancer cell lines. The mRNA expression of hTERT was upregulated after exposure to FR901228 in hTERT-negative Hep2 cells, even in the hTERT highly expressed SAS and KB cells. Moreover, co-treatment of protein synthesis inhibitor cycloheximide (CHX) resulted in the induction of hTERT transcription by FR901228. This suggests that the induction of hTERT by FR901228 requires de novo protein synthesis to some extent and is more likely a direct than an indirect effect on epigenetic changes such as histone acetylation / deacetylation. We further examined the effect of FR901228 on c-myc protein, which is one of the main hTERT transcription activators. FR901228 repressed c-myc protein only in the absence of CHX, dependent of the enhancement of de novo protein synthesis. Our results indicate that c-myc protein is repressed indirectly by FR901228 but may not contribute FR901228-induced hTERT transcription. The present study showed that the HDAC inhibitor FR901228 induced the hTERT gene by a complex mechanism that involved other transcription factors except for c-myc, in addition to the inhibition of histone deacetylation
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