256 research outputs found

    Non-Equilibrium Ionization States of GRB Environments

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    Iron spectral features are thought to be the best tracer of a progenitor of gamma-ray bursts (GRBs). The detections of spectral features such as an iron line and/or a Radiative Recombination edge and Continuum (RRC) were reported in four X-ray afterglows of GRBs. However their properties were different each other burst by burst. For example, Chandra observation of GRB 991216 reported both the strong H-like iron line together with its RRC. On the contrary, Yoshida et al. (2001) report only a detection of the strong RRC in GRB 970828 with ASCA. Since it is difficult to produce the strong RRC, we have to consider special condition for the line and/or the RRC forming region. In this paper, we point out a possibility of a ``non-equilibrium ionization state'' for the line and the RRC forming region.Comment: 10pages, 2figures. Accepted for ApJL. This is a companion paper by A.Yoshida et. a

    Cisterna magna meningiomas without dural attachment: Report of two cases

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    Meningiomas within the cisterna magna without dural attachment are extremely rare. To the best of our knowledge, only three cases of meningiomas within the cisterna magna have been reported in the literature. The authors present two cases of patient with the cisterna magna meningioma without dural attachment. (Case 1) A 36-year-old female presented with a 10-month history of numbness in the left hand. Magnetic resonance imaging (MRI) disclosed the presence of a contrast-enhanced tumor in the posterior fossa. A suboccipital craniectomy was performed, and the tumor located within the cisterna magna with no attachment to the dura. Diagnosis is made as clear cell meningioma. The postoperative course was uneventful, and a recurrence has not been observed for three years. (Case 2) A 58-year-old man presented with a well-circumscribed mass in the posterior fossa. At surgery, the tumor located within the cisterna magna with a connection to the right tenia. The tumor was totally removed without neurological deficits. At a 7-year follow-up, no evidence of a recurrence was observed. It is quite difficult to preoperatively diagnose as a cisterna magna meningioma without dural attachment. However, complete removal of the tumor should be achieved

    A large cavernous malformation of the third ventricle floor: A case report

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    Suprasellar and third ventricular region cavernous malformations originating from the floor of the third ventricle are extremely rare. We report a case of third ventricular cavernous malformation arising from the ventricle floor in a 24-year-old woman who presented with short-term memory loss and disorientation. Computed tomography revealed a suprasellar mass with calcification in the posterior chiasmatic region. T2-weighted magnetic resonance imaging revealed a mass with heterogeneous intensity and without hydrocephalus. The mass was slightly enhanced subsequent to gadolinium infusion. Using a basal interhemispheric translamina terminalis approach and a neuroendoscope, we confirmed that the tumor was located at the floor of the third ventricle and removed it. Histopathological examination confirmed the diagnosis of cavernous malformation. The postoperative course was uneventful, but the patient's short-term memory loss persisted. Despite its rarity, cavernous malformation should be suspected when a tumor is detected in the vicinity of the third ventricle floor. It is treatable through surgical resection

    Methotrexate for the treatment of juvenile idiopathic arthritis: process to approval for JIA indication in Japan

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    Methotrexate (MTX), the primary treatment for the articular-type juvenile idiopathic arthritis (JIA), is effective and brings about radiological improvement. Patient compliance is good, and it is recognized that its known side effects, namely, disruption of liver function and induction of pulmonary lesions, are unlikely to be severe at the low MTX doses that are administered. In Japan, MTX was granted approval in 1999 by the then Ministry of Health and Welfare specifically for treating rheumatoid arthritis in adult patients, allowing it be generally used in medical institutions for patients having National Health Insurance. However, in the pediatric field, its use outside the indications has so far been unavoidable, and has been left to the discretion of the physician. Finally, at the present conference, expansion of the indications of MTX for JIA was approved in Japan. It is noteworthy that this expansion of indications was achieved without requiring clinical trials on children sponsored by the pharmaceutical company: it was achieved rather by collecting necessary information through ongoing efforts (including collection and analysis of information about approval status in foreign countries, adequate evidence from the literature, implementation of a clinical use survey in Japan, etc.). It also merits attention that the maximum dose (10 mg/m2) was set on the basis of pharmacokinetic data from children, rather than relying on the dosing method and dose for adults
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