PRRX1 promotes malignant properties in human osteosarcoma.

Paired related homeobox 1 (PRRX1) is a marker of limb bud mesenchymal cells, and deficiency of p53 or Rb in Prrx1-positive cells induces osteosarcoma in several mouse models. However, the regulatory roles of PRRX1 in human osteosarcoma have not been defined. In this study, we performed PRRX1 immunostaining on 35 human osteosarcoma specimens to assess the correlation between PRRX1 level and overall survival. In patients with osteosarcoma, the expression level of PRRX1 positively correlated with poor prognosis or the ratio of lung metastasis. Additionally, we found PRRX1 expression on in 143B cells, a human osteosarcoma line with a high metastatic capacity. Downregulation of PRRX1 not only suppressed proliferation and invasion but also increased the sensitivity to cisplatin and doxorubicin. When 143B cells were subcutaneously transplanted into nude mice, PRRX1 knockdown decreased tumor sizes and rates of lung metastasis. Interestingly, forskolin, a chemical compound identified by Connectivity Map analysis using RNA expression signatures during PRRX1 knockdown, decreased tumor proliferation and cell migration to the same degree as PRRX1 knockdown. These results demonstrate that PRRX1 promotes tumor malignancy in human osteosarcoma.

The morphology of the femur in elderly Japanese females: Analysis using 3D-CT.

BACKGROUND: While various implants are currently used for the treatment of femoral trochanteric fractures in Japan, 'mismatches' have been known to occur between patient and implant type. The purpose of this study is to identify morphological characteristics of elderly Japanese females, both in terms of the shape of proximal femur and its anterior curvature in order to evaluate the suitability of implants for treatment of femoral trochanteric fractures using 3D-computed tomography (CT) scanning. METHODS: This study used CT scan data taken from 50 elderly females (aged 70 years or older). Neck-shaft (NS) angle and height of the greater trochanter (GT) were measured under defined conditions (TPI: theoretical plane to place implant). Anterior curvature of the femoral shaft was also measured. RESULTS: On average, the NS angle was found to be 128.1° and GT height was 62.4 mm. Average curvature radius was 1040 mm. As for the NS angle, the centrum-collum-diaphysis angles of existing implants (125° or 130°) are reasonable. In elderly Japanese patients, the proximal femur shows specific characteristics. As GT height is very short, the implant may easily interfere with the lateral cortex. Additionally, the curvature radius calculated (1040 mm) was smaller than that of past reports, indicating strong curvature in the Japanese elderly. CONCLUSION: Our measurement results are potentially useful in the avoidance of intraoperative trouble caused by mismatch of implants.

Subperiosteal Hematoma of the Iliac Bone: An Unusual Cause of Acute Hip Pain after a Fall.

BACKGROUND Subperiosteal hematoma (SPH) of the iliac bone is an extremely uncommon clinical entity that occurs mostly in young patients with a history of a recent fall or sports-related injury. Patients usually complain of severe hip pain after a fall, mimicking femoral neck fracture. CASE REPORT An 18-year-old female was transported to our hospital complaining of pain in her left hip after falling on her buttocks while engaging in martial arts. Ultrasound of her left iliac region revealed a subperiosteal mass on the internal aspect of the iliac bone lifting the iliac muscle. SPH of the iliac bone was suspected, which was also evident on pelvis and hip magnetic resonance imaging. Repetitive ultrasound did not reveal hematoma expansion. She was discharged from the hospital the next day without femoral neuropathy. CONCLUSIONS Physicians should be aware of our report, which highlights a patient with the rare clinical condition of SPH of the iliac bone occurring immediately after a fall. The differential diagnosis of acute hip pain, which mimics femoral neck fracture, should be considered in young patients. Ultrasound of the iliac region may be useful in detection and further management of SPH of the iliac bone.