Donald M. O'Rourke

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ATRX is a member of the SNF2 family of helicase/ATPases that is thought to regulate gene expression via an effect on chromatin structure and/or function. Mutations in the hATRX gene cause severe syndromal mental retardation associated with alpha-thalassemia. Using indirect immunofluorescence and confocal microscopy we have shown that ATRX protein is(More)
A goal of molecular genetics is to understand the relationship between basic nuclear processes, epigenetic changes and the numerous proteins that orchestrate these effects. One such protein, ATRX, contains a highly conserved plant homeodomain (PHD)-like domain, present in many chromatin-associated proteins, and a carboxy-terminal domain which identifies it(More)
OBJECTIVE We have previously shown that constitutively active epidermal growth factor receptor signaling enhances the survival and motility of engrafted neural stem cells (NSCs) when transplanted into normal adult brain. In the present study, using the C17.2 NSC line stably transfected with the constitutively active epidermal growth factor receptor vIII, we(More)
BACKGROUND AND PURPOSE Glioblastomas, brain metastases, and PCLs may have similar enhancement patterns on MR imaging, making the differential diagnosis difficult or even impossible. The purpose of this study was to determine whether a combination of DTI and DSC can assist in the differentiation of glioblastomas, solitary brain metastases, and PCLs. (More)
PURPOSE To develop and retrospectively determine the accuracy of a magnetic resonance (MR) imaging strategy to differentiate intraaxial brain masses, with histologic findings or clinical diagnosis as the reference standard. MATERIALS AND METHODS The study was HIPAA compliant and was approved by the institutional review board. A waiver of informed consent(More)
Increased expression of vascular endothelial growth factor (VEGF) contributes to the growth of many tumors by increasing angiogenesis. Although hypoxia is a potent inducer of VEGF, we previously showed that epidermal growth factor receptor amplification and loss of PTEN, both of which can increase phosphatidylinositol-3-kinase (PI3K) activity, increase VEGF(More)
Several growth factors and cytokines, including EGF, are known to induce tyrosine phosphorylation of Signal Regulatory Proteins (SIRPs). Consistent with the idea that increased phosphorylation activates SIRP function, we overexpressed human SIRPalpha1 in U87MG glioblastoma cells in order to examine how SIRPalpha1 modulates EGFR signaling pathways.(More)
The purpose of this study is to determine whether diffusion tensor imaging (DTI) metrics including tensor shape measures such as linear and planar anisotropy coefficients (CL and CP) can help differentiate glioblastomas from solitary brain metastases. Sixty-three patients with histopathologic diagnosis of glioblastomas (22 men, 16 women, mean age 58.4(More)
Glioblastomas are highly vascular malignant brain tumors that often overexpress vascular endothelial growth factor (VEGF). They also frequently overexpress epidermal growth factor receptor (EGFR) and contain regions of hypoxia, both conditions that can induce VEGF. We examined VEGF regulation in U87 MG human glioblastoma cells and in U87/T691 cells, a(More)
Our previous work showed that, compared with parental U87MG human glioblastoma cells, vascular endothelial growth factor (VEGF) mRNA levels are decreased in U87/T691, a derivative line in which epidermal growth factor receptor (EGFR) signaling is inhibited by introduction of a truncated p185(Neu) protein (A. Maity et al., Cancer Res., 60: 5879-5886, 2000).(More)