Randal S. Olshefski

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BACKGROUND Children with newly diagnosed supratentorial primitive neuroectodermal tumors (sPNET) have poor outcomes compared to medulloblastoma patients, despite similar treatments. In an effort to improve overall survival (OS) and event-free survival (EFS) and to decrease radiation exposure, the Head Start (HS) protocols treated children with newly(More)
Survivin is a gene that is widely expressed throughout the development of the normal mammalian embryo. Subcellular localisation of Survivin to both the nucleus and cytoplasm has suggested multiple functional roles, including inhibition of cell death, especially as demonstrated within a variety of malignant cell types, as well as regulation of the mitotic(More)
Bone involvement in Langerhans' cell histiocytosis (LCH) is common. Both bone scintigraphy and plain films are used to identify osseous lesions, but lack specificity for disease activity and response to therapy. FDG-PET is a sensitive technique for identifying bone lesions when histiocytes are present. To describe the potential of coincidence FDG-PET(More)
As a strategy to enhance tumor cell sensitivity to vincristine, we tested whether modulation of sphingolipid metabolism would alter vincristine cytotoxicity since this is linked to accumulation of the intermediate metabolite, ceramide. We blocked ceramide metabolism in a series of variably vincristine-resistant cell lines derived from CCRF-CEM leukemia(More)
The biological activity of human medulloblastoma tumor gangliosides very likely involves the interaction of these molecules with host cells in the tumor microenvironment. To trace the hypothesized intercellular transfer of shed medulloblastoma gangliosides, we used an in vitro dual-chamber culture system in which the tumor cells, the shed gangliosides, and(More)
Three distinct steps underlie immumosuppression by tumor gangliosides: (i) their shedding by the tumor cell, (ii) binding to target leukocytes in the tumor microenvironment, and (iii) action upon the target cell. While shedding is well documented, cell to cell transfer of shed gangliosides is not. To address this, we employed a dual chamber culture system.(More)
Children with high-grade glioma, including diffuse intrinsic pontine glioma (DIPG), have a poor prognosis despite multimodal therapy. Identifying novel therapeutic targets is critical to improve their outcome. We evaluated prognostic roles of telomere maintenance mechanisms in children with HGG, including DIPG. A multi-institutional retrospective study was(More)
Clinical drug resistance may be attributed to the simultaneous selection and expression of genes modulating the uptake and metabolism of chemotherapeutic agents. P-glycoprotein (P-gp) functions as a membrane-associated drug efflux pump whose increased expression results in resistance to anthracyclines, epipodophyllotoxins, vinca alkaloids, and some(More)
OBJECTIVE To report on a 12-year-old white male with prostatic rhabdomyosarcoma who experienced episodes of syncope attributed to concurrent amitriptyline and fluconazole therapy, confirmed by readministration. CASE REPORT The patient began experiencing syncopal episodes periodically over a seven-month period. These repeated episodes occurred when(More)
It was postulated that the therapeutic index of very toxic, oxidative drugs could be improved by concurrent treatment with other agents, such as methylene-blue, which affect the concentration of intracellular reducing agents. In support of this hypothesis, methylene-blue was found to protect mice against the toxic effects of doxorubicin without reducing(More)