Identification of driver genes and somatic mutations in cell-free DNA of patients with pulmonary lymphangioleiomyomatosis.

Next-generation sequencing of cell-free circulating DNA (cfDNA) has emerged as promising technique for identifying minimally invasive genomic profiling of tumor cells recently. However, it remains relatively unknown in LAM disease. In our study, paired cfDNA and genomic DNA (gDNA) in blood samples were obtained from 23 LAM patients and seven healthy controls to explore mutations profiles of targeted 70 cancer-related genes. As results, log2-based allele frequencies of mutations in cfDNA were significantly different from those of gDNA. By comparing the mutual mutations identified both in cfDNA and gDNA, a significant correlation was also observed. After removing mutations in gDNA, distinct somatic mutation profiles of cfDNA were observed in LAM patients. Forty of 70 targeted genes had recurrent mutations, of which ATM, BRCA2 and APC showed the highest frequency. Based on the mutation, correlation network constructed of 40 mutated genes, 11 hub genes bearing intensive interactions were highlighted, including BRCA1, BRCA2, RAD50, RB1, NF1, APC, MLH3, ATM, PDGFRA, PALB2 and BLM. Expression of the hub genes showed significant clusters between LAM patients and controls and that RAD50 and BRCA2 had the strongest associations with subject phenotypes. Myogenesis and estrogen response were confirmed to be positively regulated in LAM patients. Collectively, our study provided a landscape of genomic alterations in LAM and discovered several potential driver genes, that is, BRCA2 and RAD50, which shed a substantial light on the clinical application of key molecular markers and potential therapy targets for precision diagnosis and treatment in the future.

The influence of the sensory neurotransmitter calcitonin gene-related peptide on bone marrow mesenchymal stem cells from ovariectomized rats.

In order to explore the effects of calcitonin gene-related peptide (CGRP) on bone mesenchymal stem cells (BMSCs) from ovariectomized (OVX) rats, an OVX rat model was used. An ELISA was performed to examine the changes in CGRP level in the plasma and skeleton. The BMSCs from the sham rats were designated group A. The BMSCs from the OVX rats (groups B, C, D and E) were treated with different concentrations of CGRP (10-6, 10-8, 10-10 and 0 M) in vitro. The proliferation and osteogenic and adipogenic differentiation potential of the BMSCs were evaluated. BMSCs sheets and Bio-Oss® mixtures were transplanted into nude mice to observe the effects of CGRP on bone formation in vivo. The level of CGRP was decreased by almost 27 and 17 % in the plasma and bone, respectively, in OVX rats compared with sham rats (p < 0.05). Treatment with CGRP increased the proliferation and mineralization of BMSCs, and significantly decreased the lipid accumulation of BMSCs in a dose-dependent manner. The expression of Runx2 and Osterix was upregulated, but the expression of peroxisome proliferator-activated receptor γ was significantly downregulated in groups B, C and D compared with group E (p < 0.05). Micro computed tomography showed no difference between the images of the planted mixtures. Hematoxylin and eosin stain revealed the formation of slightly more hard bone-like structures in groups B and C. These results suggested that CGRP played a role in adjusting bone mass and strength by promoting the proliferation and osteogenic differentiation of BMSCs, as well as significantly suppressing the adipogenic differentiation of BMSCs.

Intraglandular Transplantation of Adipose-Derived Stem Cells for the Alleviation of Irradiation-Induced Parotid Gland Damage in Miniature Pigs.

PURPOSE: In a previous study, the authors verified the protective efficacy of adipose-derived stem cells (ADSCs) on the prevention of salivary gland (SG) damage induced by irradiation in mice. As a critical step before implementation in clinical practice, the present study investigated the protective effect of ADSCs in a miniature pig SG model, because miniature pigs share many characteristics with humans. MATERIALS AND METHODS: Third-passage autologous ADSCs at a concentration of 4 × 106 cells/mL were transplanted by intraglandular injection into parotid glands (PGs) immediately after local irradiation at a single dose of 20 Gy. The injection process was repeated twice a week for 6 consecutive weeks. At 12 weeks after irradiation, functional and histologic evaluations were performed by measuring salivary flow rate (SFR) and hematoxylin and eosin and periodic acid-Schiff staining. Immunohistochemical and transmission electron microscopic examinations also were conducted to evaluate amylase (AMY) production, microvessel density (MVD), and microstructural changes. RESULTS: The irradiated PGs showed remarkable decreases in SFR, AMY production, and MVD. However, transplantation of ADSCs alleviated irradiated PG morphology and function by preserving more functional acinar cells and increasing SFR and AMY production. In addition, greater MVD was observed in the ADSC-treated group than in the irradiated group. CONCLUSIONS: These results indicated that intraglandular transplantation of autologous ADSCs is an effective method to protect PGs against damage from irradiation in miniature pigs, which might have clinic application in the future.

Scaffold-Based Delivery of Bone Marrow Mesenchymal Stem Cell Sheet Fragments Enhances New Bone Formation In Vivo.

PURPOSE: Stem cell therapy is becoming a potent strategy to shorten the consolidation time and reduce potential complications during distraction osteogenesis (DO). However, the conventional local injection or scaffold-based delivery of bone marrow mesenchymal stem cell (BMSC) suspension deprives the cells of their endogenous extracellular matrix, which might dampen cell differentiation and tissue regeneration after implantation. Therefore, in our study, a BMSC sheet was established and was then minced into fragments and loaded onto a hydroxyapatite (HA) scaffold for grafting. MATERIALS AND METHODS: The purified and characterized BMSCs were grown into a cell sheet, and bone formation and mineralization capacity, as well as the cell sheet composition, were analyzed. Afterward, the in vivo osteogenic ability of cell sheet fragments (CSFs) was evaluated in immunocompromised mouse and rabbit models of DO. RESULTS: The BMSC sheet exhibited higher alkaline phosphatase activity than osteogenic cell suspension cultures. Alkaline phosphatase activity and mineral particles in the cell sheet increased further after osteogenic induction. Moreover, calcium and phosphorus were present only in the osteogenic cell sheet, along with the common elements carbon, oxygen, chlorine, sodium, and sulfur, as indicated by x-ray photoelectron spectroscopy analysis. In a mouse model, the CSF-HA complex was injected subcutaneously. Micro-computed tomography analysis showed that the osteogenic CSF-HA complex led to a considerably higher bone volume than the BMSC-HA or CSF-HA complex. The osteogenic CSF-HA specimens showed increased angiogenesis and deposition of type I collagen compared with the non-osteogenic CSF-HA or BMSC-HA specimens. Moreover, the osteogenic CSF-HA markedly improved bone consolidation and increased bone mass in DO rabbits. CONCLUSIONS: Collectively, the incorporation of osteogenic BMSC sheets into HA particles greatly promoted bone regeneration, which offers therapeutic alternatives for DO.

Preparation and Evaluation of Two Apatites with Spherical Nanocrystal Morphology.

Spherical nanocrystal of apatite has been proved to be beneficial for osteoblast growth. Two apatites with spherical nanocrystal morphology were prepared in this study by chemical wet method and further sintering process. SEM exhibited that both apatites had spherical nanocrystal morphology. The crystal morphology and size was approaching to each other. XRD showed the apatites separately were hydroxyapatite and tricalcium phosphate phases. The cellular biocompatibility was evaluated by osteoblasts for these two spherical nanocrstal apatites. The MTT result indicated a higher cell proliferation rate for spherical tricalcium phosphate group. The ALP activity assay also strongly favored the tricalcium phosphate group. RT-PCR results indicated that Collagen I had a higher transcription level on the spherical tricalcium phosphate group. SEM results showed robust cell growth on the materials. It was concluded that the spherical nanophase tricalcium phosphate was superior to the cellular biocompatibility of spherical nanophase hydroxyapatite and the results were helpful in the manufacture of more suitable tissue engineering scaffolds.

Macrophages Undergo M1-to-M2 Transition in Adipose Tissue Regeneration in a Rat Tissue Engineering Model.

Macrophages are involved in the full processes of tissue healing or regeneration and play an important role in the regeneration of a variety of tissues. Although recent evidence suggests the role of different macrophage phenotypes in adipose tissue expansion, metabolism, and remodeling, the spectrum of macrophage phenotype in the adipose tissue engineering field remains unknown. The present study established a rat model of adipose tissue regeneration using a tissue engineering chamber. Macrophage phenotypes were assessed during the regenerative process in the model. Neo-adipose tissue was generated 6 weeks after implantation. Macrophages were obvious in the chamber constructs 3 days after implantation, peaked at day 7, and significantly decreased thereafter. At day 3, macrophages were predominantly M1 macrophages (CCR7+), and there were few M2 macrophages (CD206+). At day 7, the percentage of M2 macrophages significantly increased and remained stable at day 14. M2 macrophages became the predominant macrophage population at 42 days. Enzyme-linked immunosorbent assay demonstrated transition of cytokines from pro-inflammatory to anti-inflammatory, which was consistent with the transition of macrophage phenotype from M1 to M2. These results showed distinct transition of macrophage phenotypes from a pro-inflammatory M1 phenotype to an anti-inflammatory M2 in adipose tissue regeneration in our tissue engineering model. This study provides new insight into macrophage phenotype transition in the regeneration of adipose tissue.

Addition of Adipose-Derived Stem Cells to Mesenchymal Stem Cell Sheets Improves Bone Formation at an Ectopic Site.

To determine the effect of adipose-derived stem cells (ADSCs) added to bone marrow-derived mesenchymal stem cell (MSC) sheets on bone formation at an ectopic site. We isolated MSCs and ADSCs from the same rabbits. We then prepared MSC sheets for implantation with or without ADSCs subcutaneously in the backs of severe combined immunodeficiency (SCID) mice. We assessed bone formation at eight weeks after implantation by micro-computed tomography and histological analysis. In osteogenic medium, MSCs grew to form multilayer sheets containing many calcium nodules. MSC sheets without ADSCs formed bone-like tissue; although neo-bone and cartilage-like tissues were sparse and unevenly distributed by eight weeks after implantation. In comparison, MSC sheets with ADSCs promoted better bone regeneration as evidenced by the greater density of bone, increased mineral deposition, obvious formation of blood vessels, large number of interconnected ossified trabeculae and woven bone structures, and greater bone volume/total volume within the composite constructs. Our results indicate that although sheets of only MSCs have the potential to form tissue engineered bone at an ectopic site, the addition of ADSCs can significantly increase the osteogenic potential of MSC sheets. Thus, the combination of MSC sheets with ADSCs may be regarded as a promising therapeutic strategy to stimulate bone regeneration.

Biomechanical analysis of a curvilinear distractor device for correcting mandibular symphyseal defects.

PURPOSE: The local mechanical environment is a determinant of successful transport disc distraction osteogenesis. This study assessed the biomechanics of a curvilinear distractor device for correcting mandibular symphyseal defects. MATERIALS AND METHODS: The finite element method was used to analyze an intact mandible, mandibular distractor bodies with different rail thicknesses (4, 6, 8, and 10 mm), and mandibular distractor bodies with rails and auxiliary lingual brackets. RESULTS: Rail thickness was positively correlated with maximum von Mises stress in the distractor and negatively correlated with maximum displacement of the mandibular distractor bodies. The maximum von Mises stress occurred at the junction of the rails and fixed arms. It also exceeded the yield strength of the titanium material. Compared with the maximum displacement of the intact mandible, that of the mandibular distractor bodies was visibly increased. CONCLUSION: An auxiliary lingual bracket can effectively decrease stress in such devices and displacement of mandibular distractor bodies. Rail fixation alone cannot achieve stability for distraction osteogenesis. Using an auxiliary lingual bracket effectively prevents distractor breakage and exposure.

Sinus floor elevation using osteotome technique without grafting materials: a 2-year retrospective study.

OBJECTIVE: The study aimed to assess the clinical results after osteotome technique to lift sinus floor, without graft materials in the residual bone height (RBH), below 8 mm. MATERIAL AND METHODS: Twenty-two patients aged from 19 to 70 years old in need of maxillary sinus floor augmentation were enrolled in this study. Preoperative and postoperative cone beam computerized tomography (CBCT) were taken to guide the surgery. Twenty-seven implants were inserted and followed clinically, another CBCT exam was taken at 6 months postoperatively. The diameter of the implants was 4.7 mm (SD 0.4 mm), the length was 10 mm (SD 1.0 mm). The average residual bone height was 6.7 mm (SD 1.2 mm). RESULTS: No implants were lost after the surgery and the 2 years follow-up. There was no obvious marginal bone loss during the 6 months follow-up verified by CBCT. The mean bone gain at the implant sites was 2.5 mm (SD 1.5 mm). CONCLUSION: The study verified the good and stable clinical result of the OSFE technique without using bone grafting materials when the RBH was only 4.1-8 mm.

A comparison of stromal cell-derived factor-1 expression during distraction osteogenesis and bone fracture in the mandible.

Distraction osteogenesis (DO) has been a widely applied technique in orthopedics and craniofacial surgery. However, the exact molecular mechanism by which the mechanical stimulus is translated into biological signals is still poorly understood. In this study, we examined and compared the expression of stromal cell-derived factor-1 (SDF-1) during mandibular distraction osteogenesis and fracture in rats, respectively. Forty-eight male Sprague-Dawley rats were divided into 2 groups and received unilateral distraction osteogenesis and rigid internal fixation, respectively, after the osteotomy on the right mandible. The harvested mandibles were examined radiographically, histologically, and immunohistochemically. We found that the expression of SDF-1 was mainly detected in the osteoblasts and blood vessels, and there were more intensive expression of SDF-1 in DO zones than in bone fracture zones. The quantitative analysis by enzyme-linked immunosorbent assay showed that SDF-1 reached a greater peak and maintained a longer period of up-regulation in DO than in fracture healing (P < 0.05). These results suggest that the distraction procedure markedly promotes the high expression of SDF-1 which facilitates the induction of bone formation during DO.

Engineering vascularized bone graft with osteogenic and angiogenic lineage differentiated bone marrow mesenchymal stem cells.

Tissue-engineered bone provides a promising method for the rehabilitation of acquired bone defects and congenital deformities. However, generating a vascular supply to the engineered graft remains a major challenge. We report a novel strategy to engineer vascularized bone grafts with osteogenic and angiogenic lineage differentiated marrow mesenchymal stem cells (MSCs). MSCs were expanded to form an osteogenic cell sheet using a continuous culture method and a scraping technique under osteogenic culture conditions. Another portion of MSCs was directed to differentiate into highly proliferative endothelial progenitor cells (EPCs), which were then seeded onto the cell sheets. Cell sheet-EPC complexes were implanted subcutaneously in nude mice. Cell sheets without EPCs were also implanted as a control. The mice were sacrificed, and the samples were harvested for evaluation consisting of micro-CT scanning, histological analysis and scanning electronic microscopy 4 and 8 weeks after implantation. The results showed that cell sheets were composed of viable cells and extracellular matrix and showed apparent mineralization. The obtained EPCs could express the specific antigen marker of CD31 and form capillary-like structures in vitro. The osteogenic cell sheet-EPC complexes yielded well-vascularized bone grafts 4 and 8 weeks after implantation. Both bone density and vascular density were significantly higher in the cell sheet-EPC complex group than in the control group. The results demonstrated that the introduction of EPCs could not only generate a vascular network but also increase bone formation for cell sheet-based bone engineering. These findings suggest that the strategy of engineering bone grafts with osteogenic and angiogenic lineage differentiated MSCs has great potential for clinical applications to repair large bone defects.

Platelet-rich plasma promotes angiogenesis of prefabricated vascularized bone graft.

PURPOSE: The objective was to assess the impact of platelet-rich plasma (PRP) on angiogenesis and bone formation of tissue-engineered bone in the prefabricated stage. MATERIALS AND METHODS: Both thighs of New Zealand white rabbits were used as prefabricated vascularized bone grafts using a combination of bone mesenchymal stem cells and vascular bundles in a titanium cage filled with ß-tricalcium phosphate ceramic. PRP was applied in the test group, and the same procedure was performed in the control group without the application of PRP. After 4, 8, and 12 weeks, delayed static bone scanning with technetium-99m methylene diphosphonate was performed before sacrifice, and the tissue-engineered bone samples were collected for immunohistochemical analysis using a monoclonal antibody against CD31 and histologic analysis. RESULTS: The results showed superior angiogenesis in the PRP group compared with the control group at each time point as determined by bone scintigraphy and immunohistochemical examinations. The results of histologic analysis also showed that there was more bone formation in the PRP group than in the control group at each time point. CONCLUSIONS: The application of autologous PRP was an effective strategy for increasing angiogenesis and bone formation in tissue-engineered bone and had potential significance for clinical applications.

Effects of sympathetic innervation loss on mandibular distraction osteogenesis.

Sympathetic nerve system has been proved to have important regulative effects to bone mass. However, the role of sympathetic nerve system in distraction osteogenesis (DO) is unclear. Here we show that the sympathetic nerve system plays an important role in mandibular DO. Thirty male Sprague-Dawley rats were divided into 2 groups at random. Right-side mandibular DO was performed on the 15 rats in control group (group A). Bilateral transection of cervical sympathetic trunk and right-side mandibular DO were performed on the 15 rats in the experimental group (group B). After operation, quantitative general observations, micro-computed tomography bone morphology analysis, and hematoxylin-eosin staining osseous tissue on new osteotylus in distraction gap were performed at consolidation time of 1, 14, and 28 days. SPSS 12.0 software package was used for statistical analysis. At 1 and 14 days of consolidation time, there was more continuous bone formation in the experimental group than that of the control group as determined by gross observation. Bone formation parameters including bone mineral density, bone volume-total volume ratio, bone trabeculae number as determined by micro-CT, and histological study of the test group were significantly higher than those of the control group (P < 0.05). No significant difference was noted between the 2 groups on consolidation time of 28 days. Our study suggested that the sympathetic innervation loss could improve mandibular DO and new bone formation, and the sympathetic nerve system might negatively regulate the process of DO.

Soluble Immune-Related Proteins as New Candidate Serum Biomarkers for the Diagnosis and Progression of Lymphangioleiomyomatosis.

Background: The goal of this study was to analyze serum from lymphangioleiomyomatosis (LAM) patients and healthy controls to identify novel biomarkers that could shed light on disease diagnosis and pathogenesis. Methods: From April 2017 to October 2019, qualified serum samples were obtained to explore differences in 59 immune proteins between 67 LAM patients and 49 healthy controls by the Luminex method. Results: We characterized 22 serum immune proteins that were differentially expressed in LAM patients compared with healthy people. Fifty-nine proteins were then classified into eight categories according to their biological function, and the results showed that LAM patients displayed significantly higher levels of growth factors (p = 0.006) and lower levels of costimulatory molecules (p = 0.008). LAG-3 was not only likely to have better predictive value than VEGF-D but also showed a significant difference between patients without elevated VEGF-D and healthy people. IL-18 was positively correlated with lung function and six-minute walk test (6MWT) distance and negatively correlated with St. George's Respiratory Questionnaire (SGRQ) score and pulmonary artery systolic pressure (PASP), which suggested that IL-18 was related to disease severity. PD-1 was significantly different between patients with pneumothorax and/or chylothorax and those without complications. Conclusion: We performed a large-scale serum immune factor analysis of LAM. Our study provides evidence that LAG-3 may be a novel candidate serum biomarker for the diagnosis of LAM. Future independent validation in prospective studies is warranted.

In vivo biocompatibility and degradability of a Zn-Mg-Fe alloy osteosynthesis system.

Zinc is generally considered to be one of the most promising materials to be used in biodegradable implants, and many zinc alloys have been optimized to improve implant biocompatibility, degradation, and mechanical properties. However, long-term degradation leads to the prolonged presence of degradation products, which risks foreign body reactions. Herein, we investigated the in vivo biocompatibility and degradation of a biodegradable Zn-Mg-Fe alloy osteosynthesis system in the frontal bone, mandible, and femur in beagles for 1 year. Results of the routine blood, biochemical, trace element, and histological analyses of multiple organs, peripheral blood CD4/CD8a levels, and serum interleukin 2 and 4 levels showed good biocompatibility of the Zn-Mg-Fe alloy. Zinc content analysis revealed zinc accumulation in adjacent bone tissue, but not in the liver, kidney, and spleen, which was related to the degradation of the Zn-Mg-Fe alloy. The alloy demonstrated a uniform slowing degradation rate in vivo. No degradation differences in the frontal bone, mandible, and femur were observed. The degradation products included zinc oxide [ZnO], zinc hydroxide [Zn(OH)2], hydrozincite [Zn5(OH)6(CO3)2], and hopeite [Zn3(PO4)2·4H2O]. The good biocompatibility and degradation properties of the Zn-Mg-Fe alloy render it a very attractive osteosynthesis system for clinical applications.

Facial changes in patients with skeletal class III deformity after bimaxillary surgery: an evaluation based on three-dimensional photographs registered with computed tomography.

The objective of this study was to evaluate facial soft and hard tissue changes, individually and relative to each other, in patients with skeletal class III deformity after bimaxillary surgery using three-dimensional (3D) photos obtained by white light scanning. Thirty patients with skeletal class III deformity who underwent bimaxillary surgery were selected. Each patient underwent white light scanning and spiral computed tomography (CT) within two weeks before (T0) and six months after surgery (T1). The 3D photos were registered with CT soft tissue models for T0 and T1, and the skeletal area unaffected by treatment (cranial base) was used to register T0 and T1. Then, the 3D colour-coded map was analysed to assess both skeletal and soft tissue changes between T0 and T1. Changes in the 3D coordinates of each anatomical landmark were analysed using the Student's t-test. Maxillary advancement by 2-3 mm and mandibular recession by 5-6 mm were observed; the mandible was shortened in the vertical direction. Compared with the preoperative values, the nasal columella was 0.51 mm shorter, the upper lip was 0.71 mm longer, the base of the alar cartilage was 1.38 mm wider, and the nasolabial angle became larger. The ratio of change in the position of soft tissue point Sn to hard tissue point A was 0.73:1, and that of soft tissue point Pg to hard tissue point Pog was 0.86:1. Images obtained by structured white light scanning registered with CT can be used as an alternative to study facial changes after orthognathic surgery.

miR-21 downregulates the tumor suppressor P12 CDK2AP1 and stimulates cell proliferation and invasion.

The present study was undertaken to investigate the regulation of P12(CDK2AP1) by miRNAs. A conserved target site for miR-21 within the CDK2AP1-3'-UTR at nt 349-370 was predicted by bioinformatics software and an inverse correlation of miR-21 and CDK2AP1 protein was observed. Highly specific amplification and quantification of miR-21 was achieved using real-time RT-PCR. Transfection of HaCaT cells with pre-miR-21 significantly suppressed a luciferase reporter including the CDK2AP1-3'-UTR, whereas transfection of Tca8113 with anti-miR-21 increased activity of this reporter. This was abolished when a construct mutated at the miR-21/nt 349-370 target site was used instead. Anti-miR-21-transfected Tca8113 cells showed an increase of CDK2AP1 protein and reduced proliferation and invasion. Resected primary tumors and tumor-free surgical margins of 18 patients with head and neck squamous cell carcinomas demonstrated an inverse correlation between miR-21 and P12(CDK2AP1). This study shows that P12(CDK2AP1) is downregulated by miR-21 and that miR-21 promotes proliferation and invasion in cultured cells.

Enhancing bone formation by transplantation of a scaffold-free tissue-engineered periosteum in a rabbit model.

OBJECTIVES: The periosteum plays an important role in bone regeneration. However, the harvesting of autogenous periosteum is associated with disadvantages such as donor site morbidity and limited donor sources. This study uses an osteogenic predifferentiated cell sheet to fabricate a scaffold-free tissue-engineered periosteum (TEP). MATERIAL AND METHODS: We generated an osteogenic predifferentiated cell sheet from rabbit bone marrow stromal cells (BMSCs) using a continuous culture system and harvested it using a scraping technique. Then, the in vitro characterization of the sheet was investigated using microscopy investigation, quantitative analysis of alkaline phosphatase (ALP) activity, and RT-PCR. Next, we demonstrated the in vivo osteogenic potential of the engineered sheet in ectopic sites together with a porous ß-tricalcium phosphate ceramic. Finally, we evaluated its efficiency in treating delayed fracture healing after wrapping the cell sheet around the mandible in a rabbit model. RESULTS: The engineered periosteum showed sporadic mineralized nodules, elevated ALP activity, and up-regulated gene expression of osteogenic markers. After implantation in the subcutaneous pockets of the donor rabbits, the in vivo bone-forming capability of the engineered periosteum was confirmed by histological examinations. Additionally, when wrapping the engineered periosteum around a mandibular fracture gap, we observed improved bone healing and reduced amounts of fibrous tissue at the fracture site. CONCLUSION: The osteogenic predifferentiated BMSC sheet can act as a scaffold-free TEP to facilitate bone regeneration. Hence, our study provides a promising strategy for enhancing bone regeneration in clinical settings.

Reconstruction of mandibular defects using a custom-made titanium tray in combination with autologous cancellous bone.

PURPOSE: To esthetically and functionally restore a 40-mm canine mandibular discontinuity defect using a custom-made titanium bone-grafting tray packed with autologous iliac bone. MATERIALS AND METHODS: Individualized titanium bone-grafting trays were made using a reverse engineering, computer-aided design, and rapid prototyping technique. A 40-mm discontinuity defect in the right mandibular body was created in 10 hybrid dogs. The defect was restored immediately using the tray that was densely packed with autologous cancellous iliac particles and covered with trimmed iliac chips. Sequential radionuclide bone imaging was performed postoperatively at 2, 4, 8, 12, and 24 weeks. The ratio of activity between the grafted mandible and the contralateral native mandible on each transaxial slice was calculated. The mean activity ratio was analyzed at each time point to evaluate the bone metabolism and reconstitution of the grafts. The subjects were sacrificed at 4, 12, and 24 weeks after grafting. The specimens were evaluated by postmortem gross dissection, biomechanical testing, 3-dimensional microcomputed tomographic scanning, and histologic examination. RESULTS: All the subjects tolerated the grafting operation well. Over an observation period of 24 weeks, tray extrusion occurred in 3 of the 10 subjects. Bony continuities were reconstructed in 9 of the 10 subjects. Radionuclide bone imaging revealed that the tracer uptake increased in the grafted mandible, and the radionuclide ratio between the graft and the native mandible decreased with time. Gross evaluation, microcomputed tomographic examination, biomechanical testing, and histologic examination demonstrated corticalization of the grafts. CONCLUSIONS: The use of a customized technique using reverse engineering, computer-aided design, and rapid prototyping tray containing autologous cancellous bone is a potentially powerful grafting technique for the reconstruction of mandibular discontinuity defects.

Surgical treatment of a giant neurofibroma.

Neurofibromatosis type 1, an autosomal dominant inherited disease, presents pathologic symptoms of multiple systems, including neurofibromatosis, skeletal dysplasia, café-au-lait spots in skins, and so on. A 45-year-old man with neurofibromatosis type 1 was reported in this article. The patient presented a giant neurofibroma in his head and neck, dysplasia of skull, facial bones and spinal columns, and multiple café-au-lait spots in systematic skins. Satisfactory curative effects were obtained in this case after tumor resection and prosthesis implantation.