Is mandible derived mesenchymal stromal cells superior in proliferation and regeneration to long bone-derived mesenchymal stromal cells?

Mesenchymal stromal cells(MSCs)are cells with the characteristic ability of self-renewal along with the ability to exhibit multilineage differentiation.Bone marrow(BM)is the first tissue in which MSCs were identified and BM-MSCs are most commonly used among various MSCs in clinical settings.MSCs can stimulate and promote osseous regeneration.Due to the difference in the development of long bones and craniofacial bones,the mandibular-derived MSCs(M-MSCs)have distinct differentiation characteristics as compared to that of long bones.Both mandibular and long bone-derived MSCs are positive for MSC-associated markers such as CD-73,-105,and-106,stage-specific embryonic antigen 4 and Octamer-4,and negative for hematopoietic markers such as CD-14.

Microstructures and properties of cancellous bone of avascular necrosis of femoral heads

The aim of this study is to investigate microscopic structure and characterize cancellous bone of avascular necrosis of the femoral head （ANFH）. The rabbit model of the ANFH is established. The histopathologic features are studied successfully. The differences between the steroidinjection group （S.G.） and the controlled group （C.G.） are examined, including the weight of rabbits, the hematological examination and the three-dimensional stnactures. It is found that the plasma levels of cholesterol （CHO）, high-density lipoprotein （HDL） and low-density lipoprotein （LDL） in S.G. are lower than those in C.G. when the triglyceride （TG） increased in the S.G.; but the bone mineral content （BMC） and the structural model index （SMI） of the organ and tissue decreased significantly in S.G. Three-dimensional structures of the femoral head are obtained using micro-computed tomography （CT） scanning and the mechanical model is established to analyze the influences of these structural changes on the mechanical properties of the cancellous bone.

Comparative Study on Inorganic Composition and Crystallographic Properties of Cortical and Cancellous Bone

Objective To comparatively investigate the inorganic composition and crystallographic properties of cortical and cancellous bone via thermal treatment under 700 ℃. Methods Thermogravimetric measurement, infrared spectrometer, X-ray diffraction, chemical analysis and X-ray photo-electron spectrometer were used to test the physical and chemical properties of cortical and cancellous bone at room temperature 250 ℃, 450 ℃, and 650 ℃, respectively. Results The process of heat treatment induced an extension in the a-lattice parameter and changes of the c-lattice parameter, and an increase in the crystallinity reflecting lattice rearrangement after release of lattice carbonate and possible lattice water. The mineral content in cortical and cancellous bone was 73.2wt% and 71.5wt%, respectively. For cortical bone, the weight loss was 6.7% at the temperature from 60 ℃ to 250℃, 17.4% from 250 ℃ to 450 ℃, and 2.7% from 450 ℃ to 700 ℃. While the weight loss for the cancellous bone was 5.8%, 19.9%, and 2.8 % at each temperature range, the Ca/P ratio of cortical bone was 1.69 which is higher than the 1.67 of stoichiometric HA due to the B-type CO32- substitution in apatite lattice. The CaJP ratio of cancellous bone was lower than 1.67, suggesting the presence of more calcium deficient apatite. Conclusion The collagen fibers of cortical bone were arrayed more orderly than those of cancellous bone, while their mineralized fibers ollkded similar. The minerals in both cortical and cancellous bone are composed of poorly crystallized nano-size apatite crystals with lattice carbonate and possible lattice water. The process of heat treatment induces a change of the lattice parameter, resulting in lattice rearrangement after the release of lattice carbonate and lattice water and causing an increase in crystal size and crystallinity. This finding is helpful for future biomaterial design, preparation and application.

Bone Regeneration Enhanced by Antigen-Extracted Xenogeneic Cancellous Bone Graft with rhBMP-2 in Rabbits Mandibular Defect Repair

The effects of large piece xenogeneic bone which was separated from healthy pigs as a scaffold on repair of mandibular defect was investigated and the applicability of antigen-extracted xenogeneic cancellous bone (AXCB) soaked with rhBMP-2 in bone defect repair was assessed. Mandibular defects were created in 48 New Zealand Rabbits, and then randomly divided into 4 groups, which was grafted in the mandibular defects with AXCB, AXCB soaked with rhBMP-2, autograft bone, or blank. Equal number of animals from each group was classified into three time points (4, 8, and 12 weeks) after operation for gross pathological observation, hematoxylin and eosin (H & E) staining, radiographic examination, and bone density measurement. H & E staining revealed that the area percentage of bone regeneration in the group of AXCB/rhBMP-2 graft was 27.72 ± 4.68, 53.90 ± 21.92, and 77.35 ± 9.83 when at 4, 8, and 12 weeks, which was better than that of auto bone graft, prompting that the group of AXCB/rhBMP-2 graft had commendable osteogenic effect. And comparing with the AXCB without rhBMP-2, of which the area percentage of bone regeneration was only 14.03 ± 5.02, 28.49 ± 11.35, and 53.90 ± 21.92, the osteogenic effect of AXCB/rhBMP-2 graft was demonstrated to be much better. In the group of AXCB/rhBMP-2 graft, the area percentage of bone regeneration increased, and the implanted materials were gradually degraded and replaced by autogenous bone regeneration over time. We concluded that antigen-extracted xenogeneic cancellous bone (AXCB) graft soaked with rhBMP-2 had shown excellent osteogenic effect in repair of bone defects, with good biocompability.

Microstructural Modeling and Multiscale Mechanical Properties Analysis of Cancellous Bone

This paper is devoted to the microstructure geometric modeling and mechanical properties computation of cancellous bone.The microstructure of the cancellous bone determines its mechanical properties and a precise geometric modeling of this structure is important to predict the material properties.Based on the microscopic observation,a new microstructural unit cell model is established by introducing the Schwarz surface in this paper.And this model is very close to the real microstructure and satisfies the main biological characteristics of cancellous bone.By using the unit cell model,the multiscale analysis method is newly applied to predict the mechanical properties of cancellous bone.The effective stiffness parameters are calculated by the up-scaling multi-scale analysis.And the distribution of microscopic stress in cancellous bone is determined through the down-scaling procedure.In addition,the effect of porosity on the stiffness parameters is also investigated.The predictive mechanical properties are in good agreement with the available experimental results,which verifies the applicability of the proposed unit cell model and the validness of the multiscale analysis method to predict the mechanical properties of cancellous bone.

Soft tissue aneurysmal bone cyst of the mandible:Report of a case

We report the case of a 17-year-old boy with a soft tissue aneurysmal bone cyst(STABC) located in the posterior aspect of the right mandible.Conventional radiography revealed no positive findings.On the computed tomography scan,the lesion appeared to have a nonuniform intralesional density.Magnetic resonance imaging revealed an abnormal soft tissue masses with cystic component in the superficial part of right mandibular body and angle with intact cortex.Following histopathological examination,fibro-histiocytic proliferation,blood-filled spaces and multinucleated giant cells were seen and the lesion was diagnosed as a STABC.The mass together with underlying bone and periosteum on its periphery was surgically resected under general anesthesia.Thirty-six months after surgery the patient was assessed at outpatient clinic and found no sign of recurrence This may be only the first reported case of the mandible in the English literature of this extremely rare benign tumor occurring in soft tissue.

Ultrasonic backscatter characterization of cancellous bone using a general Nakagami statistical model

The goal of this study is to analyze the statistics of the backscatter signal from bovine cancellous bone using a Nakagami model and to evaluate the feasibility of Nakagami-model parameters for cancellous bone characterization. Ultrasonic backscatter measurements were performed on 24 bovine cancellous bone specimens in vitro and the backscatter signals were compensated for the frequency-dependent attenuation prior to the envelope detection. The statistics of the backscatter envelope were modeled using the Nakagami distribution. Our results reveal that the backscatter envelope mainly followed pre-Rayleigh distributions, and the deviations of the backscatter envelope from Rayleigh distribution decreased with increasing bone density. The Nakagami shape parameter(i.e., m) was significantly correlated with bone densities(R = 0.78–0.81, p < 0.001) and trabecular microstructures(|R| = 0.46–0.78, p < 0.05). The scale parameter(i.e.,?) and signal-to-noise ratio(SNR) also yielded significant correlations with bone density and structural features. Multiple linear regressions showed that bone volume fraction(BV/TV) was the main predictor of the Nakagami parameters,and microstructure produced significantly independent contribution to the prediction of Nakagami distribution parameters,explaining an additional 10.2% of the variance at most. The in vitro study showed that statistical parameters derived with Nakagami model might be useful for cancellous bone characterization, and statistical analysis has potential for ultrasonic backscatter bone evaluation.

An Ultrasonic Backscatter Instrument for Cancellous Bone Evaluation in Neonates

Ultrasonic backscatter technique has shown promise as a noninvasive cancellous bone assessment tool. A novel ultrasonic backscatter bone diagnostic(UBBD) instrument and an in vivo application for neonatal bone evaluation are introduced in this study. The UBBD provides several advantages, including noninvasiveness, nonionizing radiation, portability, and simplicity. In this study, the backscatter signal could be measured within 5 s using the UBBD. Ultrasonic backscatter measurements were performed on 467 neonates(268 males and 199 females) at the left calcaneus. The backscatter signal was measured at a central frequency of 3.5 MHz. The delay(T_1) and duration(T_2) of the backscatter signal of interest(SOI) were varied, and the apparent integrated backscatter(AIB), frequency slope of apparent backscatter(FSAB), zero frequency intercept of apparent backscatter(FIAB), and spectral centroid shift(SCS) were calculated. The results showed that the SOI selection had a direct influence on cancellous bone evaluation. The AIB and FIAB were positively correlated with the gestational age(|R| up to 0.45, P < 0.001) when T_1 was short(< 8 μs), while negative correlations(|R| up to 0.56, P < 0.001) were commonly observed for T_1 > 10 μs. Moderate positive correlations(|R| up to 0.45, P < 0.001) were observed for FSAB and SCS with gestational age when T_1 was long(> 10 μs). The T_2 mainly introduced fluctuations in the observed correlation coefflcients. The moderate correlations observed with UBBD demonstrate the feasibility of using the backscatter signal to evaluate neonatal bone status. This study also proposes an explicit standard for in vivo SOI selection and neonatal cancellous bone assessment.

Theoretical Solutions of Dynamic Responses of Cancellous Bone

Human bone may be damaged by impact in the cases of traffic accidents and ship impact. The impact responses of cancellous bone were analyzed based on the two-phase media theory. A direct analytical method is introduced for solving this type of problems. First, flow function and potential function were introduced to decouple the controlling equations. Then direction solving method was used to obtain the solution. The solution is determined by the parameters of a (related with wave speed) and b (related with damping), as well as the boundary conditions. These two parameters a and b determine the propagation speed of the responses along the bone and the attenuation rate. It is shown that the responses: deformation, stress and pressure of the corpus medullae caused by loading, propagate toward the other end when the impact is acted on one end of the bone. The responses are discontinuous during propagate. The discontinuous surface moves with a constant speed. The responses at the cross section increase gradually from the bottom to the top because of the distribution of the loading at the boundary. The solutions can be used as the basis for certification of numerical simulation as well as the design of impact prevention of bone.

Computer-Assisted Surgery for Mandibular Reconstruction Using a Patient-Specific Titanium Mesh Tray and Particulate Cancellous Bone and Marrow

Craniomaxillofacial surgery is difficult due to the complexity of the regional anatomy. Computer-assisted surgery is a promising tool aiming to improve the safety and precision of such surgery. A computer-assisted surgical navigation approach for reconstruction of mandibular defects using a patient-specific titanium mesh tray and particulate cancellous bone and marrow (PCBM) harvested from bilateral anterior ilia is proposed. This case report involves a large multicystic ameloblastoma affecting the right mandible of a 31-year-old male patient. Following detailed clinical examination, radiological interpretation, and histopathological diagnosis, computer-assisted surgical simulation with a virtual 3-dimensional (3-D) model was designed using surgical planning software based on the pre-operative computed tomography data. Long-span segmental resection of the mandible was planned, and the defect was analyzed for reconstruction using a patient-specific reconstruction titanium mesh tray mediated with computer-aided design and manufacturing (CAD/CAM) techniques. During the actual surgery, the ultrasonic bone cutting instrument in the surgeon’s hand was connected to the navigation system to touch an anatomical position on the patient. Therefore, osteotomies were performed finely and smoothly according to the navigation images of the cutting bone line by sequentially moving the instrument. Finally, a CAD/CAM-mediated titanium mesh tray condensed by PCBM was adapted to the remaining mandibular fragments. Six months postoperatively, the patient had a good mandibular configuration and facial contour. Integration of different technologies, such as software planning and 3-D surgical simulation, combined with intraoperative navigation and CAD/CAM techniques, provides safe and precise mandibular reconstruction surgery.

Dynamic navigation system-guided trans-inferior alveolar nerve implant placement in the atrophic posterior mandible: A case report

BACKGROUND In atrophic posterior mandibular areas,where the bone height superior to the inferior alveolar nerve(IAN)is less than 6 mm,short implants are not applicable.Conventional alternatives such as IAN transposition and various alveolar bone augmentation approaches are technically demanding and prone to complications.CASE SUMMARY Computer-guided dynamic navigation implantation improves the accuracy,predictability,and safety of implant placement.This case report presents a dynamic navigation system-guided trans-IAN implant placement technique,which can successfully treat a posterior mandibular dentition defect when the bone height is only 4.5 mm.The implant was inserted into the buccal side of the IAN and was 1.7 mm away from the IAN.The implantation deviations were controlled within a satisfying range,and the long-term restoration outcome was stable.CONCLUSION Dynamic navigation system-guided trans-IAN implant placement might be a recommended technique for patients with extremely insufficient residual bone height and sufficient bone width in the posterior mandibular area.

Fanconi anemia manifesting as a squamous cell carcinoma of the mandible: a case report

Progressive bone marrow failure and development of malignancies, particularly acute myeloid leukemia and solid tumors the most important features of Fan- coni’s Anemia (FA). This paper reports the case of a 16-year-old patient with FA who developped squa- mous cell carcinoma of the mandible, ten years after the bone marrow transplantation (BMT).

Osteoblastoma of the mandible: a case report with immunohistochemical evaluation

Background: Osteoblastoma, a rare osteoblastic tumor, constitutes approximately 1% of all primary bone tu- mors. Aim: The purpose of this report is to present an osteoblastoma of the mandible, with particular emphasis on the differential diagnosis of this rare tu- mor. Methods-Results: the lesion showed osteoblast- like cells, stromal cells, osteoclast-like cells and inter- lacing trabeculae of osteoid. Because of the high cel- lularity of the tumor, immunohistochemical analysis was performed using the cell proliferation marker Ki-67, the p53 and the anti-apoptotic protein Bcl-2. The lesion demonstrated low to moderate prolifera- tive activity and no immunoreactivity was detected for p53. An interesting finding was the Bcl-2 expres- sion by the multinucleated osteoclast-like giant cells, in contrast to the lack of Bcl-2 expression from osteo- blast-like and stromal tumor cells. Conclusion: To our knowledge the Bcl-2 expression has not yet been in- vestigated in benign or malignant osteoblastic tumors. This finding may be related to the molecular mecha- nisms regulating the apoptosis of osteoclast-like tu- mor cells or their function.

Improved the biocompatibility of cancellous bone with compound physicochemical decellularization process

Due to the unique microstructures and components of extracellular matrix(ECM),decellularized scaffolds had been used widely in clinical.The reaction of the host toward decellularized scaffolds depends on their biocompatibility,which should be satisfied before applied in clinical.The aim of this study is to develop a decellularized xenograft material with good biocompatibility for further bone repair,in an effective and gentle method.The existing chemical and physical decellularization techniques including ethylene diamine tetraacetic acid(EDTA),sodium dodecyl sulfate(SDS)and supercritical carbon dioxide(SC-CO2)were combined and modified to decellularize bovine cancellous bone(CB).After decellularization,almost 100%of A-Gal epitopes were removed,the combination of collagen,calcium and phosphate was reserved.The direct and indirect contact with macrophages was used to evaluate the cytotoxicity and immunological response of the materials.Mesenchymal stem cells(MSCs)were used in the in vitro cells’proliferation assay.The decellularized CB was proved has no cytotoxicity(grade 1)and no immunological response(NO,IL-2,IL-6 and TNF-α secretion inhibited),and could support MSCs proliferated continuedly.These results were similar to that of commercial decellularized human bone.This study suggests the potential of using this kind of combine decellularization process to fabricate heterogeneous ECM scaffolds for clinical application.

The spectrum entropy estimation method for ultrasonic backscattering signal in cancellous bones

In the application of cancellous bone ultrasound diagnosis based on backscattering method, it is of great importance to estimate fast and accurately whether the valid backscattering signal exists in the received signal. We propose a fast estimation method based on spectrum entropy method. With 984 records of adult calcaneus clinical data, we estimate the validity of the backscatter signal using this method. The results of the proposed method and the results of experience-base judgement were compared and analyzed. And two key parameters, the signal range length and the segment number of the spectrum entropy, were analyzed. The results show when the signal range length is 13 I^s and the segment number is 15 20, this method can get the best result （accuracy〉95%, sensitivity〉99%, specificity〉87%）, while taking little calculation time （1.5 ms）. Therefore, this spectrum entropy method can satisfy the accuracy and real-time requirements in the ultrasonic estimation for cancellous bone.

Enhanced critical-sized bone defect repair efficiency by combining deproteinized antler cancellous bone and autologous BMSCs

Previously we have demonstrated that calcinated antler cancellous bone（CACB） has great potential for bone defect repair,due to its highly similar composition and architecture to natural extracellular bone matrix.This study is aiming at seeking for an optimal strategy of combined application of CACB and bone marrow mesenchymal stem cells（BMSCs） in bone defect repair.In vitro study demonstrated that CACB promoted the adhesion,spreading and viability of BMSCs.Increased extracellular matrix production and expression of osteogenic markers in BMSCs were observed when seeded on CACB scaffolds.The cells ceased to proliferation in the dual effect of CACB and osteogenic induction at the early stage of incubation.Hence synergistic effect of CACB combined with autologous undifferentiated BMSCs in rabbit mandible critical-sized defect repair was further evaluated.Histological analysis results showed that loading the CACB with autologous BMSCs resulted in enhanced new bone formation and angiogenesis when compared with implanted CACB alone.These findings indicate that the combination of CACB and autologous BMSCs should become potential routes to improve bone repair efficiency

Differential involvement of Wnt signaling in Bmp regulation of cancellous versus periosteal bone growth

Bone morphogenetic proteins （Bmp） are well-known to induce bone formation following chondrogenesis, but the direct role of Bmp signaling in the osteoblast lineage is not completely understood. We have recently shown that deletion of the receptor Bmprla in the osteoblast lineage with Dmpl-Cre reduces osteoblast activity in general but stimulates proliferation of preosteoblasts specifically in the cancellous bone region, resulting in diminished periosteal bone growth juxtaposed with excessive cancellous bone formation. Because expression of sclerostin （SOST）, a secreted Wnt antagonist, is notably reduced in the Bmprla- deficient osteocytes, we have genetically tested the hypothesis that increased Wnt signaling might mediate the increase in cancellous bone formation in response to Bmprla deletion. Forced expression of human SOST from a Dmpl promoter fragment partially rescues preosteoblast hyperproliferation and cancellous bone overgrowth in the Bmprla mutant mice, demonstrating functional interaction between Bmp and Wnt signaling in the cancellous bone compat^a-tent. To test whether increased Wnt signaling can compensate for the defect in periosteal growth caused by Bmprla deletion, we have generated compound mutants harboring a hyperactive mutation （A214V） in the Wnt receptor Lrp5. However, the mutant Lrp5 does not restore periosteal bone growth in the Bmprla-deficient mice. Thus, Bmp signaling restricts cancellous bone accrual partly through induction of SOST that limits preosteoblast proliferation, but promotes periosteal bone growth apparently independently of Wnt activation.

Effect of selected signals of interest on ultrasonic backscattering measurement in cancellous bones

This study examined how the signals of interest (SOI) effect on the backscattering measurement numerically based on 3-D finite-difference time-domain (FDTD) method. High resolution microstructure mappings of bovine cancellous bones provided by micro-CT were used as the input geometry for simulations. Backscatter coefficient (BSC), integrated backscatter coefficient (IBC) and apparent integrated backscatter (AIB) were calculated with changing the start (L1) and duration (L2) of the SOI. The results demonstrated that BSC and IBC decrease as L1 increases, and AIB decreases more rapidly as L1 increases. The backscattering parameters increase with fluctuations as a function of L2 when L2 is less than 6 mm. However, BSC and IBC change little as L2 continues to increase, while AIB slowly decreases as L2 continues to increase. The results showed how the selections of the SOI effect on the backscattering measurement. An explicit standard for SOI selection was proposed in this study and short L1 (about 1.5 mm) and appropriate L2 (6 mm-12 mm) were recommended for the calculations of backscattering parameters.

可降解新型聚乳酸膜在引导骨组织再生中的应用

目的探索一种可降解新型聚乳酸膜(PDLLA/PLLA)在引导骨组织再生中的应用效果。方法新西兰大白兔24只,体重2.5~3.0 kg,在动物一侧下颌骨体部近下颌骨下缘处制备10 mm×5 mm×3 mm箱状骨缺损,然后将动物随机分为实验组、对照组和空白组,每组8只。实验组动物骨缺损处填Bio-oss骨粉后将PDLLA/PLLA覆盖于缺损表面,对照组动物骨缺损处填Bio-oss骨粉后将Guidor聚乳酸可吸收膜覆盖于缺损表面,空白组动物不作处理。术后8、12周采集缺损处标本,进行大体观察、Micro-CT检查和组织病理学观察。结果实验期间各组实验动物均未发生炎症和排异反应,各组创口愈合良好,成骨活跃。大体观察显示,术后8周实验组动物成骨量较多,材料降解较少,对照组动物成骨量较实验组少,材料降解完全;术后12周实验组动物和对照组动物成骨量相当,实验组材料进一步降解,空白组动物成骨量少于实验组和对照组。术后8、12周,Micro-CT可以观察到实验组和对照组缺损区域新生骨明显多于空白组。术后8、12周,实验组动物和对照组动物新生骨相对骨体积分数(BV/TV)、骨密度(BMD)和骨小梁数量(Tb.N)均显著高于空白组动物(P<0.05),且术后8周实验组动物新生骨BV/TV高于对照组(P<0.05);但在术后12周时实验组与对照组新生骨BV/TV、BMD和Tb.N比较,差异无统计学意义(P>0.05)。组织切片观察显示,术后8周实验组动物新生骨小梁周边细胞生长活跃,并可见少量成骨细胞及破骨细胞;术后12周实验组动物骨小梁周围可见大量成骨细胞及破骨细胞,骨缺损部位骨组织密度接近周边正常骨组织。结论与对照组和空白组相比,PDLLA/PLLA呈现出了良好的生物相容性和骨传导性,可以明显促进缺损处愈合。