Drug resistance is one of the important factors that determine tumor response to chemotherapy. Several candidates for resistance to various chemotherapeutic agents have been elucidated. O6-methylguanine-DNA methyltransferase (MGMT) removes methylation damage induced by nitrosourea from the O6 position of DNA guanines before cell injury. Glutathione-S-transferase (GST) pi is also involved in nitrosourea resistance. We examined the expression of MGMT and GST pi in 18 glioblastomas (GBM) using immunohistochemistry and compared the results with patients' survival after administration of 1-(4-amino-2-methyl-5-pyrimidinyl) methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride (ACNU)-based chemotherapy. According to the Kaplan-Meier's method, although median progression free survival (PFS) of eight patients whose tumors retained high MGMT (3+ approximately 2+), and 10 patients whose tumors showed low MGMT expression (1+ approximately 0) were nine and 15 months, respectively (p = 0.09), median overall survival (OS) of the two groups were 12 and 22 months, respectively, which were significantly different (p = 0.01). GST pi expression in GBM was not a prognostic factor. It is suggested that GBM with strong staining of MGMT activity may show more resistance to ACNU-based chemotherapy compared to that with low MGMT. The simple immunohistochemical analysis of MGMT in GBM can be a useful method to determine whether ACNU or another treatment regimen should be recommended.
A 51-year-old man underwent surgery for ossification of the ligamentum flavum at the T9-T10 levels. Intraoperatively, the dura was opened unintentionally and a subcutaneous suction drain was placed. The patient complained of severe headache and nausea postoperatively. Brain computed tomography obtained 3 days after the surgery demonstrated remote cerebellar hemorrhage and hydrocephalus. Suboccipital decompression, C1 laminectomy, and ventriculostomy were performed and his symptoms subsided 2 months later. Remote cerebellar hemorrhage following spinal surgery is extremely rare, but may occur after any type of spinal surgery resulting in dural tear or intradural manipulation. Early diagnosis is particularly important for the treatment of remote cerebellar hemorrhage following spinal surgery.
A 66-year-old woman with primary Sjogren syndrome developed syringomyelia following two episodes of subarachnoid hemorrhage (SAH) due to the rupture of basilar artery aneurysms. Gait disturbance and abnormal sensation with pain over the foot and abdomen appeared 3 years after the last SAH. Magnetic resonance (MR) imaging revealed a syringomyelia throughout the thoracic cord, from the T2 to T11 levels. In addition, the thoracic cord was compressed by multiple arachnoid cysts in the ventral side of spinal cord. Computed tomography myelography revealed complete block of cerebrospinal fluid (CSF) flow at the T7 level. Surgery for microlysis of the adhesions and restoration of the CSF flow pathway was performed. Postoperatively, leg motor function slowly improved and she could walk unaided. However, abdominal paresthesia was persisted. Postoperative MR imaging revealed diminished size of the syrinxes. We should recognize syringomyelia and arachnoid cysts due to adhesive arachnoiditis as a late complication of SAH. Microlysis of the adhesions focusing on the lesion thought to be the cause of the symptoms is one of the choices to treat massive syringomyelia and arachnoid cysts associated with arachnoiditis following SAH.
Although malignant gliomas are highly invasive tumors, a characteristic that contributes to the commonly observed therapeutic failures and local disease recurrences, the molecular events that regulate invasion in these tumors remain poorly understood. Because the transcription factor RelA/NF-kappaB has been shown to regulate invasion during several cellular processes, we have examined immunohistochemically expression of the constitutively activated RelA/NF-kappaB in tissues obtained from 49 astrocytic tumors [8 diffuse astrocytomas, 9 anaplastic astrocytomas (AAs) and 32 glioblastomas (GBMs)]. In addition, we examined the in vitro effects of antisense oligonucleotides and curcumin on the expression and activation of RelA/NF-kappaB, urokinase-type plasminogen activator (u-PA) expression, migration, and invasion in the T98G glioma cell line. Expression of the constitutively activated RelA/NF-kappaB was observed in 2 (25%) of 8 cases of diffuse astrocytomas, 5 (55.6%) of 9 cases of AAs, and 30 (93.8%) of 32 cases of GBMs. This expression was significantly correlated with the malignant potential in astrocytic tumors (P < 0.001). Moreover, antisense oligonucleotides and curcumin inhibited phorbol-12-myristate-13-acetate (PMA)-induced RelA/NF-kappaB expression or activation (or both), down-regulated u-PA expression, and reduced the migration and invasive potentials of T98G glioma cells. Thus, the expression of constitutively activated RelA/NF-kappaB is associated with malignancy potential in astrocytic tumors and may play a critical role in the regulation of u-PA expression and invasiveness in gliomas. RelA/NF-kappaB may therefore be an intriguing candidate for studies aimed at understanding and prevention of the invasiveness of gliomas.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations鈥揷itations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.