兔骨髓基质干细胞骨向诱导实验研究

目的:研究兔骨髓基质干细胞(bone marrow stromal cells,BMSC)的体外培养以及骨向诱导分化情况,进一步探讨其作为骨组织工程种子细胞的可行性。方法:无菌条件下抽取兔的股骨骨髓,然后进行骨髓基质干细胞的分离和体外培养,并向成骨细胞定向诱导分化。结果:体外分离的骨髓基质细胞呈贴壁生长,改良MTT法测定显示骨髓基质细胞于第7.8天左右可达到增殖高峰;诱导后BMSC可向成骨细胞分化,细胞呈成骨细胞形态为梭形和多角形并可形成钙化结节。改良钙钴染色法检测诱导细胞碱性磷酸活性呈强阳性。扫描电镜观察细胞呈较典型的成骨细胞状态,并可见钙盐沉积。结论:骨髓基质细胞具有来源充足,取材方便,创伤小无明显并发症。骨髓基质干细胞分化增殖能力较强,成骨能力确定。所以采用骨髓基质细胞作为种子细胞构建组织工程骨有比较可靠的依据。     

Two novel distinct COL1A2 mutations highlight the complexity of genotype–phenotype correlations in osteogenesis imperfecta and related connective tissue disorders

Osteogenesis imperfecta is a heritable connective tissue disorder characterized by variable symptoms including predisposition to fractures. Despite the identification of numerous mutations, a reliable genotype–phenotype correlation has remained notoriously difficult. We now describe two patients with osteogenesis imperfecta and novel, so far undescribed mutations in the COL1A2 gene, further highlighting this complexity. A 3-year-old patient presented with features reminiscent of a connective tissue disorder, with joint hypermobility, Wormian bones, streaky lucencies in the long bones and relative macrocephaly. The patient carried a heterozygous c.1316G > A (p.Gly439Asp) mutation in the COL1A2 gene located in a triple-helix region, in which glycine substitutions have been assumed to cause perinatal lethal OI (Sillence type II). A second family with type I osteogenesis imperfecta carried a heterozygous nonsense mutation c.4060C > T (p.Gln1354X) within the last exon of COL1A2. Whereas other heterozygous nonsense mutations in COL1A2 do not lead to a phenotype, in this case the mRNA is presumed to escape nonsense-mediated decay. Therefore the predicted COL1A2 propeptide lacks the last 13 C-terminal amino acids, suggesting that the OI phenotype results from decelerated assembly and overmodification of the collagen triple helix. The presented COL1A2 mutations exemplify the complexity of COL1A2 genotype–phenotype correlation in genetic counselling in OI.     

The animal experiment of a new optimised distraction implant

Our aim was to evaluate the function of a new optimised distraction implant. Six dogs with alveolar bone defects had a total of 18 distraction, and 6 normal, implants inserted into edentulous mandibular ridges after osteotomy. Five days after insertion the distraction implants were activated at a rate of 1 mm/2 days to achieve a distraction height of 6 mm. Radiographs were taken at 0, 1, 2, and 3 months after distraction. Two dogs were killed after 1, 2, and 3 months, respectively, and 12 distraction implants taken from the different time points were evaluated by microcomputed tomographic (MicroCT) scanning and histological examination. The other 6 distraction, and the 6 normal, implants were compared after osseointegration with a fatigue test. The results showed that all the distraction implants had successfully distracted the bone to the anticipated height. Radiographs showed that the density of the regenerated bone increased steadily during the consolidation period. MicroCT showed that the regenerated bone was comparable with the native bone 3 months after distraction. Both native and regenerated bone had osseointegrated histologically by 1 month and 3 months after distraction. The experiment successfully confirmed the usefulness and feasibility of this new distraction implant, and suggests interesting clinical uses.     

Clinical manifestations and dental management of dentinogenesis imperfecta associated with osteogenesis imperfecta: Case report

Dentinogenesis imperfecta (DI) associated with osteogenesis imperfecta (OI) is a genetic disorder that affects the connective tissues and results in dentine dysplasia. This case report discusses the systemic and dental manifestations of OI and DI in a 4-year-old child, with moderate presentation of both disorders, who was treated at King Fahd Military Medical Complex in Dhahran. Dental treatment included the use of strip and stainless-steel crowns under local anesthesia, as well as behavior modification techniques. Rigorous home care instructions, including reinforcement of the oral hygiene practice and avoidance of any episode that may lead to bone fracture, were discussed with the parents. The case was reevaluated at 3-month follow-up visits, wherein the medical and dental histories were updated, the child’s growth was monitored, periodic clinical and radiographic examinations were performed, and the oral hygiene was evaluated via the debris index score and caries risk assessment. Further treatment of the permanent dentition may be needed in the future.     

大鼠下颌骨牵张成骨的蛋白质组学分析

目的:探讨用蛋白质组学iTRAQ技术分析大鼠下颌骨牵张成骨过程中新生组织蛋白表达的改变。方法:6只大鼠进行单侧下颌骨牵张,速率:0.4mm/d,牵张期为10d,术后随机分为2组,分别于下颌骨牵张成骨牵张期第10d及下颌骨牵张成骨固定期第14d取材。将取材的新生骨组织标本进行蛋白质提取及蛋白质定量检测。应用iTRAQ技术对蛋白质样本进行检测,寻找及鉴定差异蛋白。结果:应用iTRAQ技术对大鼠下颌骨牵张成骨的新生骨组织成功进行了蛋白质组学分析,质谱鉴定出置信度95%的蛋白质共567种,共鉴定出差异蛋白207个,其中上调≥1.5倍的47个,下降≤0.8倍的58个。结论:筛选出多种与牵张成骨过程中新骨形成相关的差异表达蛋白质,为进一步验证与新骨形成相关的蛋白质奠定基础。     

Results of a bone splint technique for the treatment of lower limb deformities in children with type I osteogenesis imperfecta

Background:

Children with osteogenesis imperfecta (OI) can suffer from frequent fractures and limb deformities, resulting in impaired ambulation. Osteopenia and thin cortices complicate orthopedic treatment in this group. This study evaluates the clinical results of a bone splint technique for the treatment of lower limb deformities in children with type I OI. The technique consists of internal plating combined with cortical strut allograft fixation.

Materials and Methods:

We prospectively followed nine children (five boys, four girls) with lower limb deformities due to type I OI, who had been treated with the bone splint technique (11 femurs, four tibias) between 2003 and 2006. The fracture healing time, deformity improvement, ambulation ability and complications were recorded to evaluate treatment effects.

Results:

At the time of surgery the average age in our study was 7.7 years (range 5-12 years). The average length of followup was 69 months (range 60-84 months). All patients had good fracture healing with an average healing time of 14 weeks (range 12-16 weeks) and none experienced further fractures, deformity, or nonunion. The fixation remained stable throughout the procedure in all cases, with no evidence of loosening or breakage of screws and the deformity and mobility significantly improved after surgery. Of the two children confined to bed before surgery, one was able to walk on crutches and the other needed a wheelchair. The other seven patients could walk without walking aids or support like crutches.

Conclusions:

These findings suggest that the bone splint technique provides good mechanical support and increases the bone mass. It is an effective treatment for children with OI and lower limb deformities.     

减阻牵张快速牙移动不同加力方式下骨改建效果观察

目的：观察不同牵张力下减阻牵张快速移动牙牙周组织骨改建情况。方法：Beagle犬12只,随机分为加力5天、15天、加力15天固定保持10天、90天组共四组,拔除犬双侧下颌第二前磨牙,选择下颌第一前磨牙为移动牙。将每组6颗牙齿随机分配为减阻-牵张方法组、减阻-常规方法组和常规方法组,每组2颗牙。按相应分组定期取材并制作切片,行HE、MASSON三色染色并观察。结果：减阻牵张方法组第一前磨牙远中移动量远大于减阻常规方法组和常规方法组（P〈0．05）,且3组支抗牙前移量无显著差异（P〉0．05）;组织学观察减阻牵张组张力侧成骨最为活跃,且未见牙周膜结构破坏,而压力侧少见透明样变组织。MASSON染色观察减阻牵张组新生骨较其余两组更为明显,长期保持后骨质良好。结论：减阻牵张方法能有效激发正畸移动牙牙周组织骨改建,且无不良反应,适宜强牵张力是实现牙齿快速移动的必要条件。     

Interferon gamma and T cells inhibit osteogenesis induced by allogeneic mesenchymal stromal cells

The mesenchymal stromal cells (MSCs) are reported to be immunoprivileged and osteogenic. We hypothesized that the use of allogeneic MSCs for bone repair was possible if they displayed an ability to induce similar osteogenesis in syngeneic as well as in allogeneic hosts. To test this hypothesis we used a cloned bone marrow derived cell, termed D1, isolated from Balb/c mice. The D1 cells were subcutaneously injected in syngeneic Balb/c, allogeneic immunocompetent B6, allogeneic T‐cell deficient NCr nude, and allogeneic B6 Pfp?/? Rag2?/? mice that lack matured T and B cells as well as NK‐cell cytolytic functions. D1 cells formed ectopic bones only in syngeneic or allogeneic immunocompromised hosts but not in allogeneic B6 hosts. The lack of T cells alone in allogeneic NCr mice was sufficient to promote osteogenesis in allogeneic environment. We observed a significantly higher number of T cells, B cells, macrophages and significantly higher expression of interferon gamma (IFN‐γ) in B6 allogeneic implants as compared to the syngeneic implants. These factors correlated with severe inhibition of expression of alkaline phosphatase, osteocalcin, and runx2 genes in the implants from B6 mice. Our data suggest that strategies to inhibit T cells and IFN‐γ functions will be useful for bone repair mediated by allogeneic MSCs. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31: 227–234, 2013     

Radiographic diagnosis of the occult hip fracture: Experience in 16 patients

We have benefited from using a simple, time-saving radiographic procedure for more than 5 years which may establish a correct diagnosis in most patients with clinically suspected, but initially occult, hip fractures.