Extracellular signal-regulated kinases (ERKs) are evolutionarily ancient signal transducers of the mitogen-activated protein kinase (MAPK) family that have long been linked to the regulation of osteoblast differentiation and bone formation. Here, we review the physiological functions, biochemistry, upstream activators, and downstream substrates of the ERK pathway. ERK is activated in skeletal progenitors and regulates osteoblast differentiation and skeletal mineralization, with ERK serving as a key regulator of Runt-related transcription factor 2, a critical transcription factor for osteoblast differentiation. However, new evidence highlights context-dependent changes in ERK MAPK pathway wiring and function, indicating a broader set of physiological roles associated with changes in ERK pathway components or substrates. Consistent with this importance, several human skeletal dysplasias are associated with dysregulation of the ERK MAPK pathway, including neurofibromatosis type 1 and Noonan syndrome. The continually broadening array of drugs targeting the ERK pathway for the treatment of cancer and other disorders makes it increasingly important to understand how interference with this pathway impacts bone metabolism, highlighting the importance of mouse studies to model the role of the ERK MAPK pathway in bone formation.

BACKGROUND: Variable methods have been introduced for reduction of the zygomatic fractures. The Dingman elevator is used widely to reduce these fractures but is inappropriate in certain types of fractures which require atypical traction vectors. We introduce and examine an alternate method of reducing zygomatic fractures using wire and hook traction. METHODS: A retrospective study was performed for all zygomatic fracture patients admitted between 2008 and 2014. Medially rotated fractures were reduced by using a wire looped through an intermaxillary screw secured on the medial side of the zygoma. Laterally rotated fractures were reduced using a hook introduced through an infrazygomatic skin incision. RESULTS: No accidental bleeding or incomplete reduction was observed in any of the cases. Postoperative imaging demonstrated proper reduction immediately after the operation. Follow-up computed tomography study at 1 month after operation also demonstrated proper reduction and healthy union across the previous site of fracture. CONCLUSION: The hook and wire method allowed precise application of traction forces across zygomatic fractures. The fractured bone fragment could be pulled in the direction precisely opposite to the vector of impact at the time of trauma. Soft tissue damage due to dissection was minimized. In particular, this method was effective in reducing rotated bone fragments and can be an alternative option to using the zygoma elevator.
Elevators and Escalators ; Facial Bones ; Follow-Up Studies ; Fracture Fixation ; Hemorrhage ; Humans ; Retrospective Studies ; Skin ; Traction* ; Zygoma ; Zygomatic Fractures*

This is a case report of simultaneous primary leiomyosarcomas in the spine and liver. A 64-year-old woman presented to the Seoul Paik Hospital with epigastric discomfort and constipation that she had experienced for two months. A physical examination revealed severe tenderness around the thoraco-lumbar junction. Esophagogastroduodenoscopy showed an ulceroinfiltrative lesion on the gastric angle. An abdominopelvic CT scan revealed two low attenuated lesions in the S4 and S8 regions of the liver, as well as a soft tissue mass at the T10 vertebra. Percutaneous ultrasonography-guided needle biopsy of the hepatic nodules revealed a leiomyosarcoma. The tumor at the T10 vertebra was removed to avoid spinal cord compression. The histology of this tumor was compatible with that of leiomyosarcoma. The potential primary sites for leiomyosarcoma, including the lung, thyroid, breast, kidney, genitourinary organs, and gastrointestinal tract, were subsequently investigated. No detectable abnormal findings that would suggest the origin of the tumor were found. Synchronous primary leiomyosarcomas in the spine and liver are quite rare and have a poor prognosis.
Biopsy, Needle ; Bone and Bones ; Breast ; Constipation ; Endoscopy, Digestive System ; Female ; Gastrointestinal Tract ; Humans ; Kidney ; Leiomyosarcoma ; Liver ; Lung ; Middle Aged ; Neoplasms, Multiple Primary ; Physical Examination ; Prognosis ; Seoul ; Spinal Cord Compression ; Spine ; Thyroid Gland ; Tomography, X-Ray Computed

This is a case report of simultaneous primary leiomyosarcomas in the spine and liver. A 64-year-old woman presented to the Seoul Paik Hospital with epigastric discomfort and constipation that she had experienced for two months. A physical examination revealed severe tenderness around the thoraco-lumbar junction. Esophagogastroduodenoscopy showed an ulceroinfiltrative lesion on the gastric angle. An abdominopelvic CT scan revealed two low attenuated lesions in the S4 and S8 regions of the liver, as well as a soft tissue mass at the T10 vertebra. Percutaneous ultrasonography-guided needle biopsy of the hepatic nodules revealed a leiomyosarcoma. The tumor at the T10 vertebra was removed to avoid spinal cord compression. The histology of this tumor was compatible with that of leiomyosarcoma. The potential primary sites for leiomyosarcoma, including the lung, thyroid, breast, kidney, genitourinary organs, and gastrointestinal tract, were subsequently investigated. No detectable abnormal findings that would suggest the origin of the tumor were found. Synchronous primary leiomyosarcomas in the spine and liver are quite rare and have a poor prognosis.
Biopsy, Needle ; Bone and Bones ; Breast ; Constipation ; Endoscopy, Digestive System ; Female ; Gastrointestinal Tract ; Humans ; Kidney ; Leiomyosarcoma ; Liver ; Lung ; Middle Aged ; Neoplasms, Multiple Primary ; Physical Examination ; Prognosis ; Seoul ; Spinal Cord Compression ; Spine ; Thyroid Gland ; Tomography, X-Ray Computed