Oncologic uses of the retrograde femoral nail.

Destructive lesions about the distal femur represent difficult treatment situations. Patients who present with impending or pathologic fractures require a method of fixation that provides adequate stabilization to allow for early, pain-free ambulation. Other considerations include restoration of functional range of motion, low perioperative morbidity and mortality risk, and minimal soft tissue dissection. Eleven patients with 12 pathologic or impending fractures of the distal femur who were treated with retrograde intramedullary nailing with and without polymethylmethacrylate augmentation were retrospectively reviewed. Followup averaged 17 months. Postoperative range of motion averaged 94 degrees flexion, 90% of patients reported no or modest pain, 81% were functioning with no restrictions or recreational restrictions only, and all patients were enthusiastic or satisfied with their surgical outcome. There were no perioperative mortalities, but one patient had 2 cm shortening secondary to broken distal locking screws and asymptomatic nail protrusion into the knee. Using the system for functional evaluation of reconstructive treatment of tumors of the musculoskeletal system, the average score for each patient was 25 (range, 18-30) or 83% (60%-100%) of the maximum score. The retrograde nail was an easy and successful method of fixation in this clinical setting.     

Cutaneous Presentation of Plasmablastic Post‐transplant Lymphoproliferative Disorder in a 14‐Month‐Old

Abstract: We present a 14‐month‐old female child who developed multiple erythematous nodules on her abdomen 5 months after liver and small bowel transplantation. Skin biopsy revealed a dense infiltrate of large cells in the dermal and subcutaneous layers with frequent mitotic figures. The cells were noted to have abundant cytoplasm, prominent nucleoli, and open chromatin. Immunohistochemical stains were positive for CD138, CD56, Ki67 (>90%), and lambda chain restriction. Rare mature B cells (CD20) and rare T cells (CD3) were noted. She was diagnosed with high‐grade post‐transplant lymphoproliferative disorder most consistent with plasmablastic lymphoma.     

Extracellular signal regulated kinase 5 mediates signals triggered by the novel tumor promoter palytoxin

Palytoxin is classified as a non-12-O-tetradecanoylphorbol-13-acetate (TPA)-type skin tumor because it does not bind to or activate protein kinase C. Palytoxin is thus a novel tool for investigating alternative signaling pathways that may affect carcinogenesis. We previously showed that palytoxin activates three major members of the mitogen activated protein kinase (MAPK) family, extracellular signal regulated kinase 1 and 2 (ERK1/2), c-Jun N-terminal kinase (JNK), and p38. Here we report that palytoxin also activates another MAPK family member, called ERK5, in HeLa cells and in keratinocytes derived from initiated mouse skin (308 cells). By contrast, TPA does not activate ERK5 in these cell lines. The major cell surface receptor for palytoxin is the Na+,K+-ATPase. Accordingly, ouabain blocked the ability of palytoxin to activate ERK5. Ouabain alone did not activate ERK5. ERK5 thus represents a divergence in the signaling pathways activated by these two agents that bind to the Na+,K+-ATPase. Cycloheximide, okadaic acid, and sodium orthovanadate did not mimic the effect of palytoxin on ERK5. These results indicate that the stimulation of ERK5 by palytoxin is not simply due to inhibition of protein synthesis or inhibition of serine/threonine or tyrosine phosphatases. Therefore, the mechanism by which palytoxin activates ERK5 differs from that by which it activates ERK1/2, JNK, and p38. Finally, studies that used pharmacological inhibitors and shRNA to block ERK5 action indicate that ERK5 contributes to palytoxin-stimulated c-Fos gene expression. These results suggest that ERK5 can act as an alternative mediator for transmitting diverse tumor promoter-stimulated signals.