Willy Hofstetter

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Mice lacking the proto-oncogene c-fos develop the bone disease osteopetrosis. Fos mutant mice were found to have a block in the differentiation of bone-resorbing osteoclasts that was intrinsic to hematopoietic cells. Bone marrow transplantation rescued the osteopetrosis, and ectopic c-fos expression overcame this differentiation block. The lack of Fos also(More)
Triggering receptor expressed on myeloid cells-1 (TREM-1) is a potent amplifier of pro-inflammatory innate immune reactions. While TREM-1-amplified responses likely aid an improved detection and elimination of pathogens, excessive production of cytokines and oxygen radicals can also severely harm the host. Studies addressing the pathogenic role of TREM-1(More)
The repair of bone defects with biomaterials depends on a sufficient vascularization of the implantation site. We analyzed the effect of pore size on the vascularization and osseointegration of biphasic calcium phosphate particles, which were implanted into critical-sized cranial defects in Balb/c mice. Dense particles and particles with pore sizes in the(More)
The regulatory regions for transcriptional control of the MCSF gene are unknown. We examined regulatory control in a 774-bp murine MCSF promoter transfected into MC3T3-E1 osteoblast-like and COS-7 cells. Deletion of upstream sequence from -635 increased basal activity of the promoter by at least four-fold, an increase that was maintained when PU.1, NFkappaB(More)
Efficient delivery of growth factors from carrier biomaterials depends critically on the release kinetics of the proteins that constitute the carrier. Immobilizing growth factors to calcium phosphate ceramics has been attempted by direct adsorption and usually resulted in a rapid and passive release of the superficially adherent proteins. The insufficient(More)
Prosthetic and osteosynthetic implants from metal alloys will be indispensable in orthopedic surgery, as long as tissue engineering and biodegradable bone substitutes do not lead to products that will be applied in clinical routine for the repair of bone, cartilage, and joint defects. Therefore, the elucidation of the interactions between the periprosthetic(More)
Osteoclasts originate from the hematopoietic stem cell and share a differentiation pathway with the cells of the monocyte/macrophage lineages. Development and activation of osteoclasts, and as a consequence regulation of bone resorption, depend on two growth factors: macrophage colony-stimulating factor and receptor activator of NF-κB ligand. Furthermore,(More)
The cellular and humoral mechanisms accounting for osteolysis in skeletal metastases of malignant melanoma are uncertain. Osteoclasts, the specialised multinucleated cells that carry out bone resorption, are derived from monocyte/macrophage precursors. We isolated tumour-associated macrophages (TAMs) from metastatic (lymph node/skin) melanomas and cultured(More)
Cartilage is a tissue with limited self-healing potential. Hence, cartilage defects require surgical attention to prevent or postpone the development of osteoarthritis. For cell-based cartilage repair strategies, in particular autologous chondrocyte implantation, articular chondrocytes are isolated from cartilage and expanded in vitro to increase the number(More)
Osteoclasts are multinucleated bone degrading cells. Phosphate is an important constituent of mineralized bone and released in significant quantities during bone resorption. Molecular contributors to phosphate transport during the resorptive activity of osteoclasts have been controversially discussed. This study aimed at deciphering the role of(More)