Timothy B. Rapp

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Tumors are thought to be sustained by a reservoir of self-renewing cells, termed tumor-initiating cells or cancer stem cells. Osteosarcomas are high-grade sarcomas derived from osteoblast progenitor cells and are the most common pediatric bone malignancy. In this report we show that the stem cell transcription factor Sox2 is highly expressed in human and(More)
Aneurysmal bone cysts are rare skeletal tumors that most commonly occur in the first two decades of life. They primarily develop about the knee but may arise in any portion of the axial or appendicular skeleton. Pathogenesis of these tumors remains controversial and may be vascular, traumatic, or genetic. Radiographic features include a dilated, radiolucent(More)
STUDY DESIGN A retrospective review of elderly patients treated without surgery for chronic mobile nonunions of the odontoid process. Patients were observed on an annual basis with clinical examinations and flexion/extensions plain film radiographs. OBJECTIVES To evaluate the clinical and radiographic results of elderly patients without myelopathy treated(More)
Human myxoid liposarcoma contains a characteristic t(12;16) chromosomal translocation that results in fusion of the N-terminal domain of the translocated in liposarcoma (TLS) protein to the C/EBP homologous protein (CHOP). TLS possesses structural motifs that suggest it may participate in RNA processing. We demonstrate that in human myxoid liposarcoma(More)
The introduction of the hospitalist co-management model represents an opportunity to improve care by changing the system as it applies to a small group of patients. Eighty-six consecutive patients with multiple comorbidities were selectively enrolled in an academic medical center hospitalist-orthopedic surgery co-management patient care program. Patients(More)
UNLABELLED Although functionally appealing in preserving the native knee, the condyle-sparing intercalary allograft of the distal femur may be associated with a higher risk of tumor recurrence and endoprosthetic replacement for malignant distal femoral bone tumors. We therefore compared the risk of local tumor recurrence between patients in these two types(More)
Giant-cell tumor is a benign but locally aggressive primary bone tumor that requires surgical management. Most giant-cell tumors initially are demonstrated on radiographs as distal, subarticular, geographic osteolytic lesions. Abundant giant cells on histology are reactive secondary to a neoplastic fibroblast-like stromal cell. Giant cells are present in(More)
Glomus tumors are neuromyoarterial glomus body neoplasms that most commonly occur in the subungual areas of the hand. These tumors typically present as painful solitary lesions with localized tenderness. Extradigital glomus tumors are rare and difficult to diagnose because of their varying symptoms and presentation. Misdiagnosis can result in significant(More)
Musculoskeletal tumors, both primary neoplasms and metastatic lesions, present a therapeutic challenge for the physician who wishes to provide palliative pain relief using the least invasive approach. The increasing sophistication of imaging modalities such as CT in precisely localizing neoplasm, coupled with the widespread use of radiofrequency ablation(More)
The disposition of valproic acid (di-n-propylacetate; VA) has been studied after a single oral dose of a solution of 450 mg in 7 patients with alcoholic cirrhosis and in 4 patients recovering from acute hepatitis. The diagnosis was based on biochemical function tests and histological findings. The pharmacokinetic parameters were compared with those reported(More)