A protein structural study based on the centrality analysis of protein sequence feature networks.

In this paper, we use network approaches to analyze the relations between protein sequence features for the top hierarchical classes of CATH and SCOP. We use fundamental connectivity measures such as correlation (CR), normalized mutual information rate (nMIR), and transfer entropy (TE) to analyze the pairwise-relationships between the protein sequence features, and use centrality measures to analyze weighted networks constructed from the relationship matrices. In the centrality analysis, we find both commonalities and differences between the different protein 3D structural classes. Results show that all top hierarchical classes of CATH and SCOP present strong non-deterministic interactions for the composition and arrangement features of Cystine (C), Methionine (M), Tryptophan (W), and also for the arrangement features of Histidine (H). The different protein 3D structural classes present different preferences in terms of their centrality distributions and significant features.

Effect of chitosan combined with hyaluronate on promoting the recovery of postoperative facial nerve regeneration and function in rabbits.

To determine better solutions for postoperative nerve functional recovery, the effects of chitosan and hyaluronate on perineural scar formation and neural function recovery were investigated in 40 rabbits. Rabbits were randomized into 4 groups: A (chitosan), B (chitosan + hyaluronate), C (hyaluronate) and D (control). The rabbits underwent the same parotidectomy surgery, but different materials were used to cover the operated nerves. By evaluating specific indicators, including vibrissae motion tests, neural electrophysiological examinations and extraneural examinations, it was revealed that the amplitude of vibrissae motion of all groups had increased 6 weeks after surgery. The recovery of Group B was superior compared with all other groups at 4 and 12 weeks post-surgery; however no significant differences were detected. Group B exhibited a great number of nerve fibers, thicker myelin sheath and greater nerve conduction velocity. In summary, the use of a chitosan conduit combined with sodium hyaluronate gel may prevent perineural scar formation in facial nerves and promote nerve functional recovery.

Chitosan conduit combined with hyaluronic acid prevent sciatic nerve scar in a rat model of peripheral nerve crush injury.

In the present study, the effects of hyaluronic acid (HA) combined with chitosan conduit on peripheral nerve scarring and regeneration were investigated in a rat model of peripheral nerve crush injury. A total of 60 Sprague-Dawley rats were randomly distributed into four groups (15 rats in each group), in which the nerve was either not treated (control group) or treated with chitosan conduit, hyaluronic acid, or chitosan conduit coupled with hyaluronic acid following clamp injury to the sciatic nerve. The surgical sites were evaluated by assessing the sciatic functional index, the degree of scar adhesions, the numbers of myelinated nerve fibers, the average diameter of myelinated nerve fibers and the myelin sheath thickness. Larger epineurial scar thickness was observed in the control groups compared with the treatment groups at 4, 8 and 12 weeks following surgery. There was no significant difference in scar adhesion among the four groups at 4 weeks following surgery. However, animals receiving chitosan coupled with HA demonstrated better neural recovery, as measured by reduced nerve adherence to surrounding tissues, less scar adhesion, increased number of axons, nerve fiber diameter and myelin thickness. In conclusion, the application of chitosan conduit combined with HA, to a certain extent, inhibited sciatic nerve extraneural scaring and adhesion, and promoted neural regeneration and recovery.

[An experimental study on segmental defects reconstruction of canine mandible with allogenic bone marrow mesenchymal stem cells combined with lyophilized bone].

OBJECTIVE: To investigate the effect of segmental defects reconstruction of canine mandible with allogenenic bone marrow mesenchymal stem cells (BMSC) combined with lyophilized bone. METHODS: A 30 mm segmental defect was created on the left mandibles of beagles. Beagles were randomly divided into three groups. Allogeneic bone marrow mesenchymal stem cells with lyophilized bone were used for segmental defects reconstruction in group A. Autologous bone marrow mesenchymal stem cells with freeze- dried bone were used for segmental defects reconstruction in group B. The defects of group C were repaired with lyophilized bone only. Every three beagles were sacrificed 4, 12, 24, and 48 weeks after surgery respectively. The reconstruction effect was evaluated by CT and histopathological examination. RESULTS: CT examination showed that new bones formed in group A and group B 12 weeks after surgery, but not in group C. The form of the reconstructed mandibles in the three groups recovered in 48 weeks. The small pores on the bone graft were filled with new bones in group A and group B. In group C, the pores were still evident. Histopathological examination showed that bone trabecula between allogeneic bone and autogenous bone was completely joined in group A and group B. A large number of fibrous tissue appeared around the implanted bone and new bones were formed. In group C, the lyophilized bone resorption was still not obvious, the new bone formation was significantly slower than the other two groups. There was no difference between group A and group B. CONCLUSIONS: Both allogeneic bone marrow mesenchymal stem cells and autologous mesenchymal stem cells could accelerate the bone formation.

[Clinical analysis of 12 cases of orthognathic surgery with digital computer-assisted technique].

PURPOSE: This study was to investigate the effect of the digital computer-assisted technique in orthognathic surgery. METHODS: Twelve patients from January 2008 to December 2011 with jaw malformation were treated in our department. With the help of CT and three-dimensional reconstruction technique, 12 patients underwent surgical treatment and the results were evaluated after surgery. RESULTS: Digital computer-assisted technique could clearly show the status of the jaw deformity and assist virtual surgery. After surgery all patients were satisfied with the results. CONCLUSIONS: Digital orthognathic surgery can improve the predictability of the surgical procedure, and to facilitate patients' communication, shorten operative time, and reduce patients' pain.

Reconstruction of beagle hemi-mandibular defects with allogenic mandibular scaffolds and autologous mesenchymal stem cells.

OBJECTIVE: Massive bone allografts are frequently used in orthopedic reconstructive surgery, but carry a high failure rate of approximately 25%. We tested whether treatment of graft with mesenchymal stem cells (MSCs) can increase the integration of massive allografts (hemi-mandible) in a large animal model. METHODS: Thirty beagle dogs received surgical left-sided hemi-mandibular defects, and then divided into two equal groups. Bony defects of the control group were reconstructed using allografts only. Those of the experimental group were reconstructed using allogenic mandibular scaffold-loaded autologous MSCs. Beagles from each group were killed at 4 (n = 4), 12 (n = 4), 24 (n = 4) or 48 weeks (n = 3) postoperatively. CT and micro-CT scans, histological analyses and the bone mineral density (BMD) of transplants were used to evaluate defect reconstruction outcomes. RESULTS: Gross and CT examinations showed that the autologous bone grafts had healed in both groups. At 48 weeks, the allogenic mandibular scaffolds of the experimental group had been completely replaced by new bone, which has a smaller surface area to that of the original allogenic scaffold, whereas the scaffold in control dogs remained the same size as the original allogenic scaffold throughout. At 12 weeks, the BMD of the experimental group was significantly higher than the control group (p<0.05), and all micro-architectural parameters were significantly different between groups (p<0.05). Histological analyses showed almost all transplanted allogeneic bone was replaced by new bone, principally fibrous ossification, in the experimental group, which differed from the control group where little new bone formed. CONCLUSIONS: Our study demonstrated the feasibility of MSC-loaded allogenic mandibular scaffolds for the reconstruction of hemi-mandibular defects. Further studies are needed to test whether these results can be surpassed by the use of allogenic mandibular scaffolds loaded with a combination of MSCs and osteoinductive growth factors.

[Application of computer-aided surgery in fibrous dysplasia of cranio-maxillofacial bone].

PURPOSE: To evaluate the effect of computer-aided surgical techniques in surgical treatment of cranio-maxillofacial fibrous dysplasia. METHODS: Twenty-two patients from January 1999 to December 2012 with cranio-maxillofacial fibrous dysplasia were treated in our department. According to the patients' specific conditions, surgeons designed surgical programs, and used computer-assisted surgical techniques to produce skull model and navigation template individually. The effects after surgery were evaluated. RESULTS: Twenty-two patients with resection of the bone lesions restored facial symmetry partially. The patients were followed up for 3 to 36 months, and the treatment effects were satisfactory. CONCLUSIONS: With preoperative planning, intraoperative navigation and postoperative prediction, computer-aided surgery shows its great value in improving the accuracy of cranio-maxillofacial surgery, shortening operating time and restoring facial symmetry. It is regarded as a valuable and safe surgical technique in cranio-maxillofacial surgery. Supported by Beijing Natural Science Foundation (7112124).

Recurrent Pleomorphic Adenoma of the Parotid Gland: Intraoperative Facial Nerve Monitoring during Parotidectomy.

OBJECTIVE: To determine the benefit to postoperative facial function of intraoperative facial nerve monitoring (IFNM) during recurrent pleomorphic adenoma (RPA) parotid surgery. STUDY DESIGN: Cohort study with planned data collection. SETTING: Chinese PLA General Hospital. SUBJECTS AND METHODS: Fifty-eight RPA parotidectomies were performed between 2004 and 2012. Recurrence was confirmed by histopathologic examination. None of the patients had preoperative facial palsy. Electromyography-based IFNM was used in 28 patients; 30 patients were unmonitored. The durations of surgery and the severity of postoperative facial nerve palsy were compared between the 2 groups. RESULTS: There were no significant differences between the 2 groups in the incidence of immediate or permanent facial paralysis after RPA parotidectomy (P = .95 and P = .36, respectively). However, the differences in the average duration of surgery and the severity of postoperative facial nerve palsy after total parotidectomy or wide resection were significant (P < .01 and P = .01, respectively). In contrast, these differences were not significant after superficial parotidectomies (P = .43 and P = .49, respectively). The average recovery time of temporary facial nerve paralysis was significantly shorter in the monitored group compared with the unmonitored group, independent of surgical technique (P < .01). CONCLUSION: The use of IFNM during total or wide resection RPA parotidectomy reduced the duration of surgery and the incidence of postoperative facial paralysis and enhanced recovery. However, there was little impact on facial nerve outcomes when IFNM was used during superficial RPA parotidectomy.

Clinical and radiological outcomes after treatment of sagittal fracture of mandibular condyle (SFMC) by using occlusal splint in children.

This study was designed to investigate the effects of occlusal splints in the treatment of sagittal fractures of the mandibular condyle in children. From January 1995 to December 2011, 37 sagittal fractures of the mandibular condyle in 30 patients aged 4-8 years old were included in this study. All the patients were treated with 1-2mm occlusal splints in the molar region. The mouths of the patients were kept slightly open by the occlusal splints for 3-6 months, and we reviewed the clinical and radiological remodelling of the affected condyles after treatment. Excellent (n=20) and good (n=10) clinical outcomes were achieved with full radiological remodelling seen in 19 and partial remodelling in 11. Treatment with occlusal splints is effective in delivering good results and function with minimal morbidity in children with sagittal fractures of the condyle, while permitting ongoing remodelling and growth in the short term.

The adjuvant use of stromal vascular fraction and platelet-rich fibrin for autologous adipose tissue transplantation.

Autologous adipose transplantation is rapidly gaining popularity for the restoration of soft tissue defects and lipoatrophy as well as for aesthetic improvements (e.g., facial reconstruction and rejuvenation). However, the current technique is crude that suffers from serious demerits, particularly the long-term unpredictability of volume maintenance due to resorption of the grafted adipose tissue and limited adipogenesis. We hypothesized that the adjuvant use of patient-derived adipose stromal vascular fraction (SVF) and platelet-rich fibrin (PRF) may enhance the overall outcome of autologous fat grafting in plastic and reconstructive surgery. Autologous SVF, with a mean cell number of (4.8±3.79)×107 cells/mL and a mean cell viability of 71.8%, and autologous PRF, with sustained release of multiple angiogenic growth factors, were created before surgical use. The following adipose tissue implants were injected subcutaneously into a rabbit ear's auricula according to the following study design: 2 mL adipose granules and 0.2 mL normal saline solution (AG+NS group), 2 mL adipose granules and 0.2 mL SVF (AG+SVF group), 2 mL adipose granules and 0.2 mL PRF (AG+PRF group), or 2 mL adipose granules combined with 0.1 mL SVF and 0.1 mL PRF (AG+SVF+PRF group). Histological examinations showed that the implanted adipose granules were well engrafted in the AG+SVF+PRF group, with a higher microvessel density 4 weeks postimplantation compared with the other three groups (p<0.01). Twenty-four weeks postimplantation, the resorption rates of implanted tissue in each group were 49.39%±9.47%, 27.25%±4.37%, 36.41%±8.47%, and 17.37%±6.22%, respectively, and were significantly different (p<0.01). The results demonstrated that the efficacy of adipose tissue implantation can be enhanced by using autologous PRF and SVF as therapeutic adjuvants, offering a clinically translatable strategy for soft tissue augmentation and reconstruction.

Chitosan conduits combined with nerve growth factor microspheres repair facial nerve defects.

Microspheres containing nerve growth factor for sustained release were prepared by a compound method, and implanted into chitosan conduits to repair 10-mm defects on the right buccal branches of the facial nerve in rabbits. In addition, chitosan conduits combined with nerve growth factor or normal saline, as well as autologous nerve, were used as controls. At 90 days post-surgery, the muscular atrophy on the right upper lip was more evident in the nerve growth factor and normal sa-line groups than in the nerve growth factor-microspheres and autologous nerve groups. physiological analysis revealed that the nerve conduction velocity and amplitude were significantly higher in the nerve growth factor-microspheres and autologous nerve groups than in the nerve growth factor and normal saline groups. Moreover, histological observation illustrated that the di-ameter, number, alignment and myelin sheath thickness of myelinated nerves derived from rabbits were higher in the nerve growth factor-microspheres and autologous nerve groups than in the nerve growth factor and normal saline groups. These findings indicate that chitosan nerve conduits bined with microspheres for sustained release of nerve growth factor can significantly improve facial nerve defect repair in rabbits.