Contribution of the Vertebral Posterior Elements in Anterior–Posterior DXA Spine Scans in Young Subjects

Because DXA is a projection technique, anterior–posterior (AP) measurements of the spine include the posterior elements and the vertebral body. This may be a disadvantage because the posterior elements likely contribute little to vertebral fracture resistance. This study used QCT to quantify the impact of the posterior elements in DXA AP spine measures. We examined 574 subjects (294 females and 280 males), age 6–25 yr, with DXA and QCT. QCT measures were calculated for the cancellous bone region and for the vertebral body including and excluding the posterior elements. DXA data were analyzed for the entire L₃ vertebra and for a 10‐mm slice corresponding to the QCT scan region. BMC and BMD were determined and compared using Pearson's correlation. The posterior elements accounted for 51.4 ± 4.2% of the total BMC, with a significant difference between males (49.9 ± 4.0%) and females (52.8 ± 3.9%, p < 0.001). This percentage increased with age in younger subjects of both sexes (p < 0.001) but was relatively consistent after age 17 for males and 16 for females (p > 0.10). DXA areal BMD and QCT volumetric BMD correlated strongly for the whole vertebra including the posterior elements (R = 0.83), with BMC measures showing a stronger relationship (R = 0.93). Relationships were weaker when excluding the posterior elements. We conclude that DXA BMC provides a measure of bone that is most consistent with QCT and that the contribution of the posterior elements is consistent in young subjects after sexual maturity.     

Father involvement with three-to-four-year olds at home: giving fathers a chance

This study examined fathers' perceptions regarding their home-based activities (HBA) and the influence of fathers' demographic characteristics on their perceptions and practices at home. A total of 396 fathers completed a survey questionnaire describing their demographic information, perceptions and their practices regarding their involvement in HBA. Results indicated that fathers have moderate level of practice concerning their HBA, yet they have low perception of their actual practice at HBA. In addition, there was a statistical significance in HBA due to fathers' age, educational level and specialisation which had an influence on their perceptions as well. Recommendations and implications of future research were discussed.     

Identification of an oncogenic form of the thrombopoietin receptor MPL using retrovirus-mediated gene transfer

Thrombopoietin and its receptor (MPL) are important regulators of megakaryopoiesis. We have identified an activating mutation of MPL using a combination of a retrovirus-mediated gene transfer and polymerase chain reaction-driven random mutagenesis. This point mutation causes a single amino acid substitution from Ser498 to Asn498 in the transmembrane region and abrogates factor-dependency of all interleukin-3-dependent cell lines tested. Murine interleukin-3- dependent Ba/F3 cells expressing the mutated but not the normal form of MPL were tumorigenic when transduced into syngeneic mice. Analysis of intracellular signaling pathways indicated that the mutant MPL protein constitutively activated two distinct signaling pathways, SHC-Raf-MAPK and JAK2-STAT3/STAT5.     

高交联聚乙烯与钴铬合金和陶瓷股骨头匹配使用的磨损和蠕变

髋关节骨关节炎患者进行金属对超高分子量聚乙烯(ul tra-high molecular weight polyethylene,UHMWPE)的全髋关节置换是二十世纪最为成功的外科手术之一.据文献报道使用UHMWPE衬垫的骨水泥假体20年成功率达到75%以上[1].     

The effects of whole‐body vibration training and vitamin D supplementation on muscle strength,muscle mass,and bone density in institutionalized elderly women: A 6‐month randomized,controlled trial

Sarcopenia and osteoporosis represent a growing public health problem. We studied the potential benefit of whole‐body vibration (WBV) training given a conventional or a high dose of daily vitamin D supplementation in improving strength, muscle mass, and bone density in postmenopausal women. In a 2 × 2 factorial‐design trial, 113 institutionalized elderly females aged over 70 years (mean age 79.6 years) were randomly assigned either to a WBV or a no‐training group, receiving either a conventional dose (880 IU/day) or a high dose (1600 IU/day) of vitamin D₃. The primary aim was to determine the effects of 6 months of WBV and/or vitamin D supplementation on isometric and dynamic strength, leg muscle mass, and hip bone mineral density (BMD). Additionally, the increase in 25‐hydroxyvitamin D [25(OH)D] levels between conventional and high‐dose supplementation was compared. After 6 months of treatment, dynamic muscle strength, hip BMD, and vitamin D serum levels improved significantly in all groups, whereas isometric strength and muscle mass did not change. When compared with no training, the WBV program did not result in additional improvements. When compared with 880 IU, a high dose of 1600 IU of vitamin D did result in higher serum vitamin D levels but did not result in additional improvements. In institutionalized women older than 70 years, the WBV training protocol tested is not more efficient in enhancing muscle mass, strength, and hip BMD compared with vitamin D supplementation. A higher dose of 1600 IU of vitamin D does not provide additional musculoskeletal benefit in this population compared with conventional doses. © 2011 American Society for Bone and Mineral Research.     

Implantation of an intercostal nerve stimulator for chronic abdominal pain

Chronic abdominal pain is not uncommon and can be difficult to manage. We present the case of a 17-year-old man with a 4-year history of chronic abdominal pain. The patient had previously undergone abdominal surgery by way of laparoscopic appendicectomy and right nephrectomy for a mal-rotated kidney. The patient continued to suffer right-sided abdominal pain which was not controlled by analgesia. We report the successful implantation of a right D11 intercostal nerve stimulator to control the patient’s pain. This is the first report of an implantable intercostal nerve stimulator to control intractable chronic abdominal pain.