Establishment of an Animal Model of Dog Bite Injuries.

Nowadays dog bite is becoming a world public health problem. Therefore, the study aimed to develop a dog bite animal model that is helpful to solve these problems. In this study, the skull of an adult dog was scanned. The three-dimensional model of the dog maxillofacial bones and dentition was built by MIMICS. Next, the model was printed with Co-Cr alloy by using selective laser sintering technology to develop the dog bite simulation pliers. Then, to simulate dog bite to most, the maximum bite force of the pliers was measured and actions contained in dog bite process was analyzed. Afterwards, according to action analysis results, rabbits were bitten by the prepared instrument in actions that simulate dog's bite. Finally, the reproducibility and controllability of this animal model of dog bite injuries was validated in an in vivo study. The results showed a reliable animal model of dog bite injuries has been developed in this study. The sites and severities of the injuries could be adjusted as the operator wishes and the animal model of dog bite injuries was highly repeatable. This study also indicates the feasibility of using digital technology in establishing animal bite models.

Hmmr Acts as a Key Regulator in the ADSCs Proliferation and Mitosis.

Obesity is a common chronic health problem that requires lifelong efforts for the successful treatment. The proliferation of ADSCs is an essential step in the development of obesity. Identifying key regulators of ADSCs will be a novel strategy for adipogenesis inhibition and obesity prevention. In this study, transcriptomes of 15532 ADSCs were firstly profiled by single cell RNA-sequencing. On the basis of gene expression patterns, 15 cell subpopulations (six defined cell types) were distinguished. A subpopulation was identified as CD168+ ADSCs, and it was demonstrated to play a vital role in ADSCs proliferation. Furthermore, Hmmr, a specific marker gene of CD168+ ADSCs was found to be a critical gene associated with ADSCs proliferation and mitosis. Hmmr knockout resulted that ADSCs growth nearly arrested and aberrant nuclear division occurred. Finally, it was revealed that Hmmr promoted ADSCs proliferation through the extracellular signal-regulated kinase 1/2 signaling pathway. This study identified Hmmr as a key regulator in ADSCs proliferation and mitosis, and suggested that Hmmr may be a novel target for obesity prevention.

Application of customized integration titanium mesh in the treatment of complicated zygomatic complex fractures: A prospective randomized clinical study.

The present study aimed to quantitatively evaluate the outcomes of the application of customized integration titanium mesh (CITM) in treating unilateral complicated zygomatic complex fractures. A prospective, randomized, controlled clinical study was conducted. Patients were randomly divided into the experimental group who underwent treatment with CITM, and the control group who underwent treatment just with traditional titanium plates. The X2 test and student t-test were used for statistical analyses. Twenty patients who required surgery for unilateral complicated zygomatic complex fracture were included in this study. The results showed that the mean of average distance (AD) between pre- and postoperative CT measurements was 0.487 mm in the experimental group and 1.173 mm in the control group (P < 0.001). Compared with the control group, the experimental group had superior zygomatico-facial symmetry (P＜0.05), a shorter average operation time (150 min versus 229 min; P < 0.001), and a higher rate of anatomic reduction (80.0% versus 30.0%; P＜0.05). In conclusion, CITM deserves to be promoted for the treatment of complicated zygomatic complex fractures. TRIAL REGISTRATION: www.chictr.org.cn (ChiCTR1800016818).

Virtual surgical planning is a useful tool in the surgical management of mandibular condylar fractures.

PURPOSE: The aim of this study is to evaluate the application value of virtual surgical planning in the management of mandibular condylar fractures and to provide a reliable reference. METHODS: This was a prospective randomized controlled study and recruited 50 patients requiring surgical treatment for their mandibular condylar fractures. The inclusion criteria were patients (1) diagnosed with a condylar fracture by two clinically experienced doctors and required surgical treatment; (2) have given consent for the surgical treatment; and (3) had no contraindications to the surgery. Patients were excluded from this study if: (1) they were diagnosed with a non-dislocated or only slightly dislocated condylar fracture; (2) the comminuted condylar fracture was too severe to be treated with internal reduction and fixation; or (3) patients could not complete follow-up for 3 months. There were 33 male and 17 female patients with 33 unilateral condylar fractures and 17 bilateral condylar fractures included. The 50 patients were randomly (random number) divided into control group (25 patients with 35 sides of condylar fractures) and experimental group (25 patients with 32 sides of condylar fractures). Virtual surgical planning was used in the experimental group, but only clinical experience was used in the control group. The patients were followed up for 1, 3, 6 and 12 months after operation. Variables including the rate of perfect reduction by radiological analysis, the average distance of deviation between preoperative and postoperative CT measurements using Geomagic software and postoperative clinical examinations (e.g., mouth opening, occlusion) were investigated for outcome measurement. SPSS 19 was adopted for data analysis. RESULTS: The average operation time was 180.60 min in the experimental group and 223.2 min in the control group. One week postoperatively, CT images showed that the anatomic reduction rate was 90.63% (29/32) in the experimental group and 68.57% (24/35) in the control group, revealing significant difference (X2 = 4.919, p = 0.027). Geomagic comparative analysis revealed that the average distance of deviation was also much smaller in the experimental group than that in the control group (0.639 mm vs. 0.995 mm; t = 3.824, p < 0.001). CONCLUSION: These findings suggest that virtual surgical planning can assist surgeons in surgical procedures, reduce operative time, and improve the anatomic reduction rate & accuracy, and thus of value in the diagnosis and treatment of condylar fractures.

Mini suture anchor: An effective device for reduction and fixation of displaced temporomandibular joint disc with intracapsular condylar fracture.

PURPOSE: The main aim is to provide clinical reference for the application of mini suture anchor in the reduction and fixation of displaced temporomandibular joint (TMJ) disc with intracapsular condylar fracture. METHODS: From October 2018 to October 2019, 21 patients (31 sides) with intracapsular condylar fractures and articular disc displacement from West China Hospital of Stomatology, Sichuan University were included. The selection criteria were: (1) mandibular condylar fractures accompanied by displacement of the TMJ disc, confirmed by clinical examination, CT scan and other auxiliary examinations; (2) indication for surgical treatment; (3) no surgical contraindications; (4) no previous history of surgery in the operative area; (5) no facial nerve injury before the surgery; (6) informed consent to participate in the research program and (7) complete data. Patients without surgical treatment were excluded. The employed patients were followed up at 1, 3, 6 and 12 months after operation. Outcomes were assessed by success rate of operation, TMJ function and radiological examination results at 3 months after operation. Data were expressed as number and percent and analyzed using SPSS 19.0. RESULTS: All the surgical procedures were completed successfully and all the articular discs were firmly attached to the condyles. The articular disc sufficiently covered the condylar head after the fixation. The fixation remained stable when the mandible was moved in each direction by the surgeons. No complications occurred. The functions of the TMJ were well-recovered postoperatively in most cases. CT scan revealed that the screws were completely embedded in the bone without loosening or displacement. CONCLUSION: Mini suture anchor can provide satisfactory stabilization for the reduced articular disc and also promote the recovery of TMJ functions.

Hyperbaric Oxygen Therapy: An Effective Auxiliary Treatment Method for Large Jaw Cysts.

Background: To evaluate hyperbaric oxygen therapy (HBOT) on infection rates and repair rates during the treatment of large jaw cysts. Methods: A prospective randomized, non-blinded, controlled clinical trial included 90 patients with jaw cysts, randomly divided into three groups. Patients were treated with enucleations and bone substitute was used in the experimental and control groups. The experimental group received HBOT. The primary predictor variable was HBOT. The infection rate, repair rate, preoperative volume of the jaw cysts, age, and sex were statistically analyzed. The Fisher exact test was used to compare the infection rate and postoperative complications. The repair rate of the bone defects was analyzed using the repeated-measures analysis of variance and the least significant difference tests. The Kendall's coefficient of concordance and Kappa statistics were calculated to evaluate the consistency between the two investigators. Results: The infection rate was 3.4% in the experimental group, 14.3% in the blank group, and 32.1% in the control group (P<0.05). The repair rate in the experimental group was significantly higher than in the control and blank groups at 1, 3 and 6 months after surgery (P<0.05). Conclusion: The results showed that HBOT reduced the postoperative infection rate following the enucleation of large jaw cysts with bone substitute filling, and it also improved the bone repair rate.

Precise locating and cutting of the bone lid with a digital template during the treatment of large mandibular cysts: A case series study.

The aim of the study was to investigate the efficacy and safety of a digital template in the bone lid technique during enucleation of large mandibular cysts. Six patients were enrolled in this study. Patients' preoperative CT data were collected to design and produce the digital templates. The bone lids were located and cut under the guidance of the digital templates, and then replanted and fixed following cyst enucleation. Postoperative clinical symptoms were observed and recorded from postoperative days 1-7. The follow-up visits were set at 3, 6, and 12 months. The cystic lesions were exactly and fully exposed without the need for secondary bone removal. The contours of the mandibles recovered well, with excellent sealing of the defects. Apart from one case with postoperative infection and one case with 2-month numbness of the lower lip, no other complications occurred. Six months after the surgery, patients' appearance and function were well-restored. A digital template in the bone lid technique during enucleation of large mandibular cysts was effective and safe.

Rabbit umbilical cord mesenchymal stem cells: A new option for tissue engineering.

BACKGROUND: The source and availability of cells for tissue engineering in large scale research or clinical trials requires special attention. We propose the idea of applying rabbit umbilical cord mesenchymal stem cells for this purpose. METHODS: Here, the structure of the rabbit umbilical cord was analyzed and compared to that of human umbilical cord, both macroscopically and histologically. Next, we isolated, cultured and identified the proliferative activity and immunological characteristics of rabbit umbilical cord mesenchymal stem cells in vitro using mixed lymphocyte reaction, flow cytometry and an enzyme-linked immunosorbent assay. Furthermore, we evaluated the effects of biphasic calcium phosphate ceramic scaffolds seeded with rabbit umbilical cord mesenchymal stem cells in rat cranial defect models using multiple techniques, including radiological, histological and immunohistochemistry. RESULTS: In vitro studies demonstated a high level of proliferation and multi-lineage differentiation potential in rabbit umbilical cord mesenchymal stem cells. Rabbit umbilical cord mesenchymal stem cells exibited low immunogenicity properties and immune suppression capability with respect to both the allogeneic and xenogeneic immune response. The results of the in vivo study showed that rabbit umbilical cord mesenchymal stem cells could promote osteogenesis in heterogeneous hosts. CONCLUSIONS: The rabbit umbilical cord mesenchymal stem cells may be a new source for tissue engineering.

The novel long noncoding RNA lncRNA-Adi regulates adipogenesis.

Adipogenesis participates in many physiological and pathological processes, such as obesity and diabetes, and is regulated by a series of precise molecular events. However, the molecules involved in this regulation have not been fully characterized. In this study, we identified a long noncoding (lnc)RNA, lncRNA-Adi, which is highly expressed in adipose tissue-derived stromal cells (ADSCs) that are differentiating into adipocytes. Knockdown of lncRNA-Adi impaired the adipogenic differentiation ability of ADSCs. Moreover, lncRNA-Adi was found to interact with microRNA (miR)-449a to enhance the expression of cyclin-dependent kinase (CDK)6 during adipogenesis. The mechanism by which lncRNA-Adi regulates adipogenesis was determined to involve an lncRNA-Adi-miR-449a interaction that competes with the CDK6 3' untranslated region to increase CDK6 translation and activate the pRb-E2F1 pathway to promote adipogenesis. These findings provide valuable information and a new study angle to search for therapeutic targets against metabolic disorders such as obesity and diabetes.

Does the Deep Layer of the Deep Temporalis Fascia Really Exist?

PURPOSE: It has been widely accepted that a split of the deep temporal fascia occurs approximately 2 to 3 cm above the zygomatic arch and extends into the superficial and deep layers. The deep layer of the deep temporal fascia is between the superficial temporal fat pad and the temporal muscle. However, during procedures, the authors noted the absence of the deep layer of the deep temporal fascia between the superficial temporal fat pad and the temporal muscle. This prospective study was conducted to clarify the presence or absence of a deep layer of the deep temporal fascia. MATERIALS AND METHODS: Anatomic layers of the soft tissues of the temporal region, with reference to the deep temporal fascia, were investigated in 130 cases operated on for zygomaticofacial fractures using the supratemporal approach from June 2013 to June 2017. RESULTS: Of 130 surgeries, the authors found the absence of a thick, obviously identifiable, fascial layer between the superficial temporal fat pad and the temporal muscle. In fact, the authors found nothing above the temporal muscle in most cases. In a few cases, the authors observed only a small amount of scattered loose connective tissue between the superficial temporal fat pad and the temporal muscle. CONCLUSIONS: This clinical study showed the absence of a thick, obviously identifiable, fascial layer between the superficial temporal fat pad and the temporal muscle, which suggests that a "deep layer of the deep temporal fascia" might not exist.

[Application of surgical navigation technology in the treatment of zygomatic fracture].

Zygomatic fracture is one of the most common mid-facial fractures. Zygomatic fracture often leads to open-mouth and chewing dysfunctions, which are often associated with pronounced zygomatic facial deformity, causing psychological and physiological problems in patients. The complicated anatomical structures associated with zygomatic fracture often make treatment difficult. Surgical navigation technology provides a new auxiliary method for improving the treatment results for zygomatic fracture. This review aims to provide a comprehensive overview of the application of surgical navigation technology in the treatment of zygomatic fracture.

Human Umbilical Cord Mesenchymal Stem Cells: A New Therapeutic Option for Tooth Regeneration.

Tooth regeneration is considered to be an optimistic approach to replace current treatments for tooth loss. It is important to determine the most suitable seed cells for tooth regeneration. Recently, human umbilical cord mesenchymal stem cells (hUCMSCs) have been regarded as a promising candidate for tissue regeneration. However, it has not been reported whether hUCMSCs can be employed in tooth regeneration. Here, we report that hUCMSCs can be induced into odontoblast-like cells in vitro and in vivo. Induced hUCMSCs expressed dentin-related proteins including dentin sialoprotein (DSP) and dentin matrix protein-1 (DMP-1), and their gene expression levels were similar to those in native pulp tissue cells. Moreover, DSP- and DMP-1-positive calcifications were observed after implantation of hUCMSCs in vivo. These findings reveal that hUCMSCs have an odontogenic differentiation potency to differentiate to odontoblast-like cells with characteristic deposition of dentin-like matrix in vivo. This study clearly demonstrates hUCMSCs as an alternative therapeutic cell source for tooth regeneration.

Bone marrow-derived stromal cells are more beneficial cell sources for tooth regeneration compared with adipose-derived stromal cells.

Tooth loss is presently a global epidemic and tooth regeneration is thought to be a feasible and ideal treatment approach. Choice of cell source is a primary concern in tooth regeneration. In this study, the odontogenic differentiation potential of two non-dental-derived stem cells, adipose-derived stromal cells (ADSCs) and bone marrow-derived stromal cells (BMSCs), were evaluated both in vitro and in vivo. ADSCs and BMSCs were induced in vitro in the presence of tooth germ cell-conditioned medium (TGC-CM) prior to implantation into the omentum majus of rats, in combination with inactivated dentin matrix (IDM). Real-time quantitative polymerase chain reaction (RT-qPCR) was used to detect the mRNA expression levels of odontogenic-related genes. Immunofluorescence and immunohistochemical assays were used to detect the protein levels of odontogenic-specific genes, such as DSP and DMP-1 both in vitro and in vivo. The results suggest that both ADSCs and BMSCs have odontogenic differentiation potential. However, the odontogenic potential of BMSCs was greater compared with ADSCs, showing that BMSCs are a more appropriate cell source for tooth regeneration.

Snail and Slug collaborate on EMT and tumor metastasis through miR-101-mediated EZH2 axis in oral tongue squamous cell carcinoma.

microRNAs(miRNAs) can regulate epithelial-mesenchymal transition (EMT) through transcription factors, however, little is known whether EMT transcription factors can modulate miRNAs and further induce EMT and cancer metastasis. Here we show that overexpression of Snail and Slug leads to a mesenchymal phenotype and morphology and enhances cell invasion along with stem cell properties in squamous cell carcinoma of oral tongue (OTSCC) cells. Repression of miR-101 expression by Snail and Slug is essential for Snail/Slug-induced malignant phenotypes. The suppression of miR-101 subsequently activates EZH2, the sole histone methyltransferase, inducing EMT, migration and invasion of OTSCC cells. Importantly, co-overexpression of Slug and Snail correlates with poor survival and elevated EZH2 expression in two independent patient cohorts of OTSCC specimens. These findings defined a Snail and Slug/miR-101/EZH2 pathway as a novel regulatory axis of EMT-mediated-microRNA signaling.

MiR-540 as a novel adipogenic inhibitor impairs adipogenesis via suppression of PPARγ.

A better understanding of the molecular mechanisms in adipogenesis may provide new insights into adipose tissue-related diseases. Recently, microRNAs (miRNAs) have emerged as a class of epigenetic regulators of stem cell differentiation. In this study, we found that miR-540 was an essential negative regulator of adipogenic differentiation in adipose tissue-derived stromal cells (ADSCs). Lentivirus-mediated overexpression of miR-540 resulted in blockade of the expression of C/EBP-α and PPARγ, the two master transcription factors of adipogenesis, and deficient lipid accumulation, whereas inhibition of miR-540 promoted these processes. Target gene reporter assays showed that miR-540 directly targeted the 3'-untranslated region (3'UTR) of PPARγ, resulting in a decrease of PPARγ protein expression. Collectively, these data suggest that miR-540 represents a new adipogenic inhibitor by, at least in part, targeting PPARγ.

[Progress of temporomandibular joint prosthesis].

The anatomically and functionally complex nature of the temporomandibularjoint (TMJ) makes its reconstruction one of the most challenging tasks faced by surgeons who operate in the head and neck. TMJ prosthesis is one of the important techniques in the reconstruction of TMJ. The main indications for TMJ prosthesis include ankylosis, fractures of condylar that can't be fixed, trauma or tumor, end-stage TMJ disturbance, and TMJ dysplasia caused by Hallermann-Streiff syndrome. TMJ replacement aims to enhance the function of TMJ, alleviate pain, and prevent serious complications. TMJ prosthesis is advantageous in oral and maxillofacial surgery because it can imitate normal anatomic morphology and adhere to the host. Moreover, the use of other materials is no longer necessary and functional training can be started postoperatively at once, among others. Prosthetic materials have leading and promoting functions in the development of joint prosthesis. Good design, fit shape, and fixation are the necessary conditions for prosthesis to serve its function. Investigation of joint biomechanics is also necessary. With the rapid developments in material science, joint biomechanics, and other related subjects, TMJ prosthesis has been significantly improved in terms of its materials, design, fit shape, and fixation techniques. In addition, the development of TMJ prosthesis would expand its applications. This review intends to provide an overview about the progress and clinical application of TMJ prosthesis.

C-kit induces epithelial-mesenchymal transition and contributes to salivary adenoid cystic cancer progression.

Epithelial-mesenchymal transition (EMT) is associated with salivary adenoid cystic cancer (ACC) progression and metastasis. Here, we report that ectopic overexpression of c-kit in ACC cell lines is sufficient for acquisition of mesenchymal traits, enhanced cell invasion, along with stem cell properties defined by the presence of a CD133+/CD44+ cell subpopulation. c-kit positively regulated expression of known EMT inducers, also activating TGF-ß to contribute to EMT. c-kit itself was induced by TGF-ß in ACC cell lines and required for TGF-ß-induced EMT. Xenograft experiments showed that c-kit cooperated with oncogenic Ras to promote tumorigenesis in vivo. Finally, in human specimens of ACC, we found that c-kit was abnormally overexpressed and correlated with the prognosis of ACC. Our findings define an important function for c-kit in ACC progression by orchestrating EMT, and they implicate this gene product as a marker of poor prognosis in this disease.

HIF-α/MIF and NF-κB/IL-6 axes contribute to the recruitment of CD11b+Gr-1+ myeloid cells in hypoxic microenvironment of HNSCC.

CD11b+Gr-1+ myeloid cells have gained much attention due to their roles in tumor immunity suppression as well as promotion of angiogenesis, invasion, and metastases. However, the mechanisms by which CD11b+Gr-1+ myeloid cells recruit to the tumor site have not been well clarified. In the present study, we showed that hypoxia could stimulate the migration of CD11b+Gr-1+ myeloid cells through increased production of macrophage migration inhibitory factor (MIF) and interleukin-6 (IL-6) by head and neck squamous cell carcinoma (HNSCC) cells. Hypoxia-inducible factor-1α (HIF-1α)- and HIF-2α-dependent MIF regulated chemotaxis, differentiation, and pro-angiogenic function of CD11b+Gr-1+ myeloid cells through binding to CD74/CXCR2, and CD74/CXCR4 complexes, and then activating p38/mitogen-activated protein kinase (MAPK) and phosphatidylinositide 3-kinases (PI3K)/AKT signaling pathways. Knockdown (KD) of HIF-1α and HIF-2α in HNSCC cells decreased MIF level but failed to inhibit the CD11b+Gr-1+ myeloid cell migration, because HIF-1α/2α KD enhanced nuclear factor κB (NF-κB) activity that increased IL-6 secretion. Simultaneously blocking NF-κB and HIF-1α/HIF-2α had better inhibitory effect on CD11b+Gr-1+ myeloid cell recruitment in the hypoxic zone than individually silencing HIF-1α/2α or NF-κB. In conclusion, the interaction between HIF-α/MIF and NF-κB/IL-6 axes plays an important role in the hypoxia-induced accumulation of CD11b+Gr-1+ myeloid cells and tumor growth in HNSCC.