Cell aging,the fundamental unit of biological decay,is responsible for senile disease. With the development of research,the mechanism of cell aging has been investigated in molecular level. Two hypotheses have emerged to explain the reason that lamins contribute to cell aging,one is the mechanical stress hypothesis,the other is the gene expression hypothesis. The latter proposes that mutations in A-type lamins lead to abnormal tissue-specific gene regulation. In recent years,the molecular mechanisms of lamins causing cell aging primarily include gene mutation,Zmpste24 mutation,CAAX mutation and other mutations. These mutations in the gene that encode nuclear lamins cause nuclear lamina damage directly and result in cell aging,which have been associated with several degenerative disorders.

[Objective] To study the application and clinical result of extended trochanteric osteotomy in hip joint revision.[Methods]Thirteen hips in 13 patients who were treated with extended trochanteric osteotomy in hip joint revision from 2003 to 2007 were followed-up for an average time of 32.3 months.The revision reasons,Harris score,osteotomed length,and the oeteotomed union time were analyzed.[Results]The average preoperative Harris score of all patients was 38(24~68),the average postoperative Harris score was 77(57-100),with the improvement of 39 points.The average osteotomed length from the tip of great trochanter to distal osteotomy site was 12.4 cm(9~15.1 cm).The osteotomy sites were healed in 11 patients at 3 months and 2 patients at 6 months after operation.[Conclusion]Extended trochanteric osteotomy is useful in hip joint revision.After osteotomy femoral prosthesis and cement could be taken out easily,and the osteotomy site could be healed easily.

Hutchinson-Gilford progeria syndrome (HGPS) is an early onset severe premature aging disorder due to a point mutation in LMNA gene which encodes nuclear lamin A/C. The mutation activates a cryptic splice site within exon 11 of LMNA, resulting in a 50-amino acid in-frame deletion in prelamin A. However, it is not clear how the mutation in a structural protein under the nuclear envelope could give rise to premature aging phenotypes. Recent studies showed that various abnormalities have been found in nuclear structures and functions of HGPS cells, mainly including progerin accumulation and nuclear morphology abnormalities, altered nuclear mechanical properties, changes of histone methylation patterns and epigenetic control, gene misregulation, p53 signalling activation, and increased genomic instability. Two hypotheses recently emerged in the explanation of the pathogenic mechanisms contributing to HGPS. No effective clinical intervention has been developed so far for HGPS. Several fascinating therapeutic strategies have recently been provided, such as farnesyltransferase inhibitors, antisense oligonucleotides and RNA interference. HGPS has been considered to be a model for studying the mechanisms responsible for normal aging. This study will help to elucidate the physiological functions of lamin A and nuclear envelope, together with their roles in normal aging process and diseases.

Epigenetics refers to non-coding sequence changes such as DNA methylation, histone modifications, chromosome remodeling and non-coding RNA regulation.Histone modifications include acetylation, phosphorylation, methylation, ubiquitination and ADP ribosylation.The combinations of different histone modifications, known as "histone code", are dynamic during development and differentiation and play important roles in the regulation of gene expressions in spatial-temporal manners.The modification on a particular residue in a histone affects not only the modifications at different residues in its own protein but also other histones.The histone modifications is a complicated network and the regulation remains elusive.

A comparison was made for the correlation and application scope of the statistical methods commonly used by hospitals for their efficiency measurement.Hospital data processed with PCA (principal component analysis)for dimension reduction were used in a correlation analysis for the results of ratio analysis (RA),stochastic frontier analysis(SFA)and data envelopment analysis(DEA).The authors hold that the RA can expediently display the order of hospital efficiency,the SFA demands a stricter premise yet presents more stable results,while the DEA boasts greater relative advantages and thus suitable for processing hospital efficiency measurement tasks of multi-input and multi-output indexes.

Objective To study the effects of marrow mesenchymal stem cells on heart functions and ventricular remodeling after myocardial infarction in rats. Methods Myocardial infarction model was established by ligation of the left anterior descending coronary artery (LAD) in adult SD rats. 4 and 8 weeks after MMSCs implantation,hemodynamic evaluations,left ventricular weight/body weight ratio and heart weight/body weight ratio were determined. HE staining was performed for counting microvasculars and Van Gieson staining was used for measurements and calculation of the myocardial fibrillar collagen. Then we investigated the migration and evolution of MSCs in vivo by fluorescent microscope. Results HR was significantly decreased in transplantation MMSCs group. Eight weeks after transplantation,body weight in transplantation MMSCs group reached that of control group. At the same time,SBP,DBP and MBP were significantly increased in transplantation MMSCs group. HR was significantly decreased in transplantation MMSCs group. Secondly,left ventricular weight/body weight ratio and heart weight/bodyweight ratio were significantly decreased 4 weeks after transplantation MMSCs. Then the ratio was significantly decreased 8 weeks after transplantation MMSCs. Thirdly density of microvasculars was increased at the boundary of infarction site in the animals transplanted MMSCs. Finally,total volume of the myocardial fibrillar collagen was reduced in the MMSCs treated groups after MI. Conclusion Transplanting MMSCs can improve the ventricular remodeling and heart functions in acute MI rat models.

Objective To investigate outcomes of different operations in treatment of cervical spinal fracture in patients with ankylosing spondylitis and summarize experiences and bases in selection of operation.Methods A retrospective study was done on 19 patients with cervical spinal fracture following ankylosing spondylitis treated between 2005 and 2011 and received complete follow-up.Among them,nine patients were treated with combined anterior and posterior surgical approach (combined treatment group),seven with single posterior surgical approach (posterior approach group) and three with single anterior surgical approach (anterior approach group).Clinical data,follow-up data and image outcome of the patients were collected and compared.Results All patients received average 14 months of follow-up (range,12-20 months).In combined treatment group,the fracture was healed at postoperative 4-6 months.One patient had palsy of recurrent laryngal nerve but was recovered at postoperative three months.Seven patients with incomplete spinal cord injury had at least one level improvement in neurological function according to American Spinal Injury Association (ASIA) classification.No implant loosening or shifting were found in internal fixation.In posterior approach group,fracture was healed at postoperative 4-6 months,with no surgical complications,loosening or shifting of implants.Five patients with incomplete spinal cord injury had at least one level improvement in neurological function according to ASIA classification.In anterior approach group,an additional operation for implant loosening was performed in one patient at postoperative four weeks.The other two patients obtained fracture healing at postoperative four and five months respectively,without implant loosening.Condusions Combined anterior and posterior approaches can not only be the first choice for treatment of cervical spinal fracture following ankylosing spondylitis,but also be used for patients with bone defect at fracture site or separation at fracture end,with no necessity of postoperative external fixation.Single posterior reduction and fixation can be considered in patients with transvertebral fracture in the absence of bone defect,separation at fracture end,displacement or slight displacement,with necessary postoperative external fixation.However,single anterior fixation takes risk of implant failure and needs postoperative external fixation.

Objective To study the effects of marrow mesenchymal stem cells on heart functions and ventricular remodeling after myocardial infarction in rats. Methods Myocardial infarction model was established by ligation of the left anterior descending coronary artery (LAD) in adult SD rats. 4 and 8 weeks after MMSCs implantation, he-modynamic evaluations, left ventricular weight/body weight ratio and heart weight/body weight ratio were determined. HE staining was performed for counting microvasculars and Van Gieson staining was used for measurements and calculation of the myocardial fibrillar collagen. Then we investigated the migration and evolution of MSCs in vivo by fluorescent microscope. Results HR was significantly decreased in transplantation MMSCs group. Eight weeks after transplantation, body weight in transplantation MMSCs group reached that of control group. At the same time, SBP, DBP and MBP were significantly increased in transplantation MMSCs group. HR was significantly decreased in transplantation MMSCs group. Secondly, left ventricular weight/body weight ratio and heart weight/body weight ratio were significantly decreased 4 weeks after transplantation MMSCs. Then the ratio was significantly decreased 8 weeks after transplantation MMSCs. Thirdly density of microvasculars was increased at the boundary of infarction site in the animals transplanted MMSCs. Finally, total volume of the myocardial fibrillar collagen was reduced in the MMSCs treated groups after MI. Conclusion Transplanting MMSCs can improve the ventricular remodeling and heart functions in acute MI rat models.

Objective To investigate surgical strategy and outcome for cervical metastasis in different anatomical segments.Methods Data of 31 patients,who had undergone surgical treatment for cervical metastasis from 2001 to 2009,were retrospectively analyzed.Two anatomical regions were defined:upper cervical spine (C1 and C2)and subaxial cervical spine plus cervicothoracic junction (C3-T1).VAS score,Frankel grade,Tomita score and Karnofsky performance scale were used to evaluate pain,neurological status,expected survival time and general health.The improvement of symptoms,survival time and characteristics of surgical strategies for different anatomical regions were analyzed.Results Twenty-four patients were followed up successfully.An effective recovery in neck pain and quality of life was found after operation.The median survival time was 45.0 months.In upper cervical spine group,the surgical strategies included posterior occipitocervical fixation combined with 125I seed brachytherapy and other surgical methods,and the median survival time 48.0 months) of patients who underwent 125I seed brachytherapy was longer than that 22.0 of patients treated with other surgical methods.In C3-T1 metastasis group,patients who underwent combined anterior-posterior approach total spondylectomy had a longer survival time than those treated with anterior corpectomy.Conclusion Surgical treatment can effectively relief neck pain,maintain or improve neurological function and improve quality of life.Doctors should choose different surgical strategies according to anatomical region of cervical metastasis.For upper cervical spine,the main purpose of surgery is to stabilize the cervical spine; the posterior occipitocervical fixation is usually chosen,and the 125I seed brachytherapy is useful in local control of metastasis.For subaxial cervical spine and cervicothoracic junction,the anterior corpectomy is usually chosen,and a combined anterior-posterior approach total spondylectomy can be used for patients with corresponding conditions.

Objective To evaluate the role of the short-segment transpedicular instrumentation and fusion in the treatment of thoracic and lumbar spine unstable fractures. Methods We reviewed 121 patients of thoracic and lumbar vertebral fractures treated by short-segment transpedicular instrumentation (attachment of one level above the fracture to one level below the fracture) by using an AO Universal Spine System (USS), plus posterolateral fusion by using autogenous iliac crest bone graft. Results Out of the 121 cases, 104 had been followed clinically, radiographically, and functionally for 12 to 72 months (mean 31.3 months). Follow-up observations showed that, 101 patients (97.1%) had neurological function improvement more than one Frankel grade (3 no change), the average loss of vertebral body height basically reversed to normal (mean 58.3% preoperatively versus mean 3.2% postoperatively, with mean loss of 2.1% in follow-up), and the kyphotic angles were basically corrected (mean 29?preoperatively versus mean 3.4?postoperatively, with mean loss of 3.4?in follow-up). Conclusions The short-segment transpedicular instrumentation and fusion can provide excellent reduction and fixation, indirect decompression, and stabilization for unstable thoracic and lumbar fractures. The USS may be effectively employed in the short-segment fixation of thoracic and lumbar fractures.[