Siglec-15 protein regulates formation of functional osteoclasts in concert with DNAX-activating protein of 12 kDa (DAP12).

Osteoclasts are multinucleated giant cells that reside in osseous tissues and resorb bone. Signaling mediated by receptor activator of nuclear factor (NF)-κB (RANK) and its ligand leads to the nuclear factor of activated T cells 2/c1 (NFAT2 or NFATc1) expression, a critical step in the formation of functional osteoclasts. In addition, adaptor proteins harboring immunoreceptor tyrosine-based activation motifs, such as DNAX-activating protein of 12 kDa (DAP12), play essential roles.

[Excessive bleeding in the patients with past history of Hassab's operation].

We report two cases of massive perioperative bleeding and multiple organ failure with past history of Hassab's operation. Massive bleeding occurred during laparotomy and thoracocentesis in each case. After Hassab's operation, collateral circulation and coagulation disorders could develop, and unanticipated massive bleeding might occur.