Enhanced sensitivity and long-term G2 arrest in hydrogen peroxide-treated Ku80-null cells are unrelated to DNA repair defects.

While the Ku complex, comprised of Ku70 and Ku80, is primarily involved in the repair of DNA double-strand breaks, it is also believed to participate in additional cellular processes. Here, treatment of embryo fibroblasts (MEFs) derived from either wild-type or Ku80-null (Ku80(-/-)) mice with various stress agents revealed that hydrogen peroxide (H(2)O(2)) was markedly more cytotoxic for Ku80(-/-) MEFs and led to their long-term accumulation in the G2 phase. This differential response was not due to differences in DNA repair, since H(2)O(2)-triggered DNA damage was repaired with comparable efficiency in both Wt and Ku80(-/-) MEFs, but was associated with differences in the expression of important cell cycle regulatory genes. Our results support the notion that Ku80-mediated cytoprotection and G2-progression are not only dependent on the cell's DNA repair but also may reflect Ku80's influence on additional cellular processes such as gene expression.

Monitoring of somatosensory and motor evoked potentials during open reduction and internal fixation of pelvis and acetabular fractures.

Monitoring of motor and somatosensory evoked potentials provides instantaneous intraoperative assessment of a patient's neurologic status. Monitoring of the sciatic nerve through motor and somatosensory evoked potentials can be used during open reduction and internal fixation of pelvic and acetabular fractures. A review of 12 pelvic and acetabular fractures treated with open reduction and internal fixation was conducted and assessed with a combination of intraoperative motor and somatosensory evoked potential monitoring. Results revealed intraoperative motor evoked potential monitoring was 100% sensitive and 100% specific in predicting postoperative sciatic nerve deficits, whereas somatosensory evoked potentials were not accurate in predicting postoperative sciatic nerve deficits. Combined monitoring of the sciatic nerve with motor and somatosensory evoked potentials is beneficial at predicting postoperative sciatic nerve deficits during open reduction and internal fixation of pelvic and acetabular fractures.

Subcapital femoral neck fracture after closed reduction and internal fixation of an intertrochanteric hip fracture: a case report and review of the literature.

A subcapital femoral neck fracture in a healed intertrochanteric fracture treated by an open reduction and internal fixation is a rare, but catastrophic, event. We present the case of an 86-year-old woman, a community ambulator, who sustained a displaced right intertrochanteric hip fracture during a fall. She was treated with closed reduction and internal fixation with a dynamic compression hip screw and side plate. Four months later, she was noted to have a displaced subcapital femoral neck fracture and underwent hip screw and side plate hardware removal and cemented bipolar hemiarthroplasty. Both postoperative recoveries were uncomplicated, and she was discharged to a rehabilitation facility able to ambulate with minimal assistance. This devastating complication in patients with osteoporosis may be prevented by deeper placement of the dynamic hip compression lag screw to within 5 mm to 8 mm of the subchondral bone, which may decrease the stress forces in the subcapital femoral neck.

Complications of iliac crest bone graft harvesting.

Autologous bone grafts harvested from the iliac crest are commonly used in reconstructive orthopaedic surgery. Autologous bone is used to help promote bone healing in fractures and to provide structural support for reconstructive surgery. The results of autologous bone grafting are more predictable than the use of xenografts, cadaveric allografts, or synthetic bone substitutes because autologous bone grafts provide osteoinductive and osteoconductive properties, are not immunogenic, and are usually well incorporated into the graft site. In a retrospective review of 414 consecutive cases of iliac crest bone graft procedures performed at Brooke Army Medical Center from 1983 to 1993, 41 (10%) minor and 24 (5.8%) major complications were identified. Minor complications included superficial infections, superficial seromas, and minor hematomas. Major complications included herniation of abdominal contents through massive bone graft donor sites, vascular injuries, deep infections at the donor site, neurologic injuries, deep hematoma formation requiring surgical intervention, and iliac wing fractures. Harvesting of iliac crest bone graft can be associated with significant morbidity. However, with adequate preoperative planning and proper surgical technique, the incidence of these complications can be reduced.

Prophylaxis of deep venous thrombosis after total hip arthroplasty by using intermittent compression of the plantar venous plexus.

A randomized, prospective, blinded study comparing the efficacy of prophylaxis of deep venous thrombosis by using (A) heparin-aspirin therapy, (B) intermittent pulsatile pneumatic-pump compression of the plantar venous plexus, or (C) both methods, was conducted in patients undergoing elective total hip replacement arthroplasty. Duplex ultrasonography was obtained in all 75 patients before surgery, at 1 week, and 2 weeks after surgery, to detect the presence or absence of deep venous thrombosis, with venograms confirming all positive results. Five of 25 patients in group A (heparin-aspirin) developed deep vein thrombosis. No deep venous thrombi were detected in groups B or C. One pulmonary embolus was detected in group A. The reduction in detectable deep venous thrombosis by the use of intermittent compression of the plantar venous plexus was significant. Wound drainage was decreased by 2 to 3 days (P < 0.05) in group B. It is concluded that, in this group of 75 consecutive patients, intermittent pulsatile compression of the plantar venous plexus was superior to heparin/aspirin pharmacologic prophylaxis for the prevention of deep venous thrombosis proximal to the calf.

Skeletal muscle injuries.

Muscular injuries are extremely common in athletes. Treatment of these injuries is based on a solid understanding of anatomy, physiology, and healing of skeletal muscle. Injuries discussed include contusions, hematomas, myositis ossificans, delayed onset soreness, strain, rhabdomyolysis, and lacerations. Diagnosis and treatment of these injuries is essential for the sports medicine physician.