Clinical validation of an AI-based motion correction reconstruction algorithm in cerebral CT.

OBJECTIVES: To evaluate the clinical performance of an artificial intelligence (AI)-based motion correction (MC) reconstruction algorithm for cerebral CT. METHODS: A total of 53 cases, where motion artifacts were found in the first scan so that an immediate rescan was taken, were retrospectively enrolled. While the rescanned images were reconstructed with a hybrid iterative reconstruction (IR) algorithm (reference group), images of the first scan were reconstructed with both the hybrid IR (motion group) and the MC algorithm (MC group). Image quality was compared in terms of standard deviation (SD), signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), the mean squared error (MSE), peak signal-to-noise ratio (PSNR), structural similarity index (SSIM), and mutual information (MI), as well as subjective scores. The diagnostic performance for each case was evaluated accordingly by lesion detectability or the Alberta Stroke Program Early CT Score (ASPECTS) assessment. RESULTS: Compared with the motion group, the SNR and CNR of the MC group were significantly increased. The MSE, PSNR, SSIM, and MI with respect to the reference group were improved by 44.1%, 15.8%, 7.4%, and 18.3%, respectively (all p < 0.001). Subjective image quality indicators were scored higher for the MC than the motion group (p < 0.05). Improved lesion detectability and higher AUC (0.817 vs 0.614) in the ASPECTS assessment were found for the MC to the motion group. CONCLUSIONS: The AI-based MC reconstruction algorithm has been clinically validated for reducing motion artifacts and improving diagnostic performance of cerebral CT. KEY POINTS: • An artificial intelligence-based motion correction (MC) reconstruction algorithm has been clinically validated in both qualitative and quantitative manner. • The MC algorithm reduces motion artifacts in cerebral CT and increases the diagnostic confidence for brain lesions. • The MC algorithm can help avoiding rescans caused by motion and improving the efficiency of cerebral CT in the emergency department.

Functional analysis of long-chain non-coding RNA in oral squamous cell carcinoma.

BACKGROUND: This study aimed to investigate the expression profile of long-chain non-coding RNA (lncRNA) in oral squamous cell carcinoma (OSCC) and to explore the biological functions of differentially expressed lncRNA in the cancer tissues as compared with adjacent normal tissues, and the differentially expressed lncRNAs related to OSCC were screened. METHODS: High-throughput lncRNA microarray assay was used to detect the expression of lncRNA and mRNA in the OSCC tissues and adjacent normal tissues from five patients. The expression profiles of the lncRNA and mRNA in the cancer tissues and adjacent normal tissues were analyzed and the differentially expressed lncRNA and mRNAs were identified. The differentially expressed mRNA was analyzed with GO, Pathway and disease annotation enrichment database, and the mRNAs related to the tumor and the lncRNA-mRNA co-expression network were employed to screen the key lncRNA related to the occurrence and development of OSCC. RESULTS: A total of 3,022 differentially expressed lncRNAs and 4,364 differentially expressed mRNAs were identified in the OSCC tissues as compared with adjacent normal tissues. A further analysis revealed 130 major differentially expressed mRNAs related to the tumor. When the correlation was >0.99 or <-0.99 and P value was <0.05, there were 73 differentially expressed mRNA in case of mRNA /lncRNA co-expression. The intersection of two gene symbols resulted in the nine lncRNAs closely related to the OSCC, in which five showed up-regulation and six had down-regulation. Based on the co-expression of the lncRNAs and mRNAs (correlation 40.99 or correlation -0.99 and P value <0.05), there were differentially expressed mRNAs with co-expression with lncRNA. CONCLUSIONS: The differentially expressed lncRNAs identified in this study are related to the occurrence and development of OSCC. This may provide new therapeutic targets and biomarkers for OSCC and is also helpful for further investigation of pathogenesis of OSCC.

Comparative Outcomes of Block and Cancellous Iliac Bone Grafting in Older Unilateral Alveolar Cleft Patients.

OBJECTIVE: To compare osseous outcomes of block and cancellous iliac bone grafting in older unilateral alveolar cleft patients. DESIGN: Retrospective and observational follow-up study. SETTING: Cleft Lip and Palate Centre, Department of Oral and Maxillofacial Surgery, Affiliated Hospital of Stomatology, Nanjing Medical University, China. PATIENTS: Forty-five nonsyndromic patients with unilateral complete alveolar cleft were enrolled in this study (25 patients in block bone graft group and 20 patients in cancellous bone graft group). INTERVENTIONS: In cancellous bone graft group, the alveolar cleft was filled with iliac cancellous bone particulate. In group of block bone graft, the harvested bone block was trimmed and fixed in alveolar defect. MAIN OUTCOME MEASURES: A novel method was proposed to investigate the volume and density of residual bone graft at 1-week, 3- and 6-month, 1- and 2-year postoperatively based on cone beam computed tomography scans. RESULTS: No difference in bone graft volume was found between 2 groups at 1-week and 3-month postoperatively; however, the residual volume of block bone graft group was significantly larger than that of cancellous bone graft group at 6-month, 1- and 2-year postoperatively. The bone density of block bone graft group was lower at 1-week and 3-month postoperatively but was comparable at 6-month, 1- and 2-year postoperatively. Our method was reliable and accurate to identify the range of residual bone graft when the boundary of grafted bone could not be identified clearly. CONCLUSION: Block bone graft could achieve comparable bone density and retain a greater amount of residual bone comparing to cancellous bone graft.

A Deep Learning-Based Radiomics Model for Differentiating Benign and Malignant Renal Tumors.

OBJECTIVES: To investigate the effect of transfer learning on computed tomography (CT) images for the benign and malignant classification on renal tumors and to attempt to improve the classification accuracy by building patient-level models. METHODS: One hundred ninety-two cases of renal tumors were collected and identified by pathologic diagnosis within 15 days after enhanced CT examination (66% male, 70% malignant renal tumors, average age of 62.27 ±â€¯12.26 years). The InceptionV3 model pretrained by the ImageNet dataset was cross-trained to perform this classification. Five image-level models were established for each of the Slice, region of interest (ROI), and rectangular box region (RBR) datasets. Then, two patient-level models were built based on the optimal image-level models. The network's performance was evaluated through analysis of the receiver operating characteristic (ROC) and five-fold cross-validation. RESULTS: In the image-level models, the test results of model trained on the Slice dataset [accuracy (ACC) = 0.69 and Matthews correlation coefficient (MCC) = 0.45] were the worst. The corresponding results on the ROI dataset (ACC = 0.97 and MCC = 0.93) were slightly better than those on the RBR dataset (ACC = 0.93 and MCC = 0.85) when freezing the weights before the mixed6 layer. Compared with the image-level models, both patient-level models could discriminate better (ACC increased by 2%-5%) on the RBR and Slice datasets. CONCLUSIONS: Deep learning can be used to classify benign and malignant renal tumors from CT images. Our patient-level models could benefit from 3D data to improve the accuracy.

Anatomical Study and Clinical Application of Facial Artery Perforator Flaps in Intraoral Reconstruction: Focusing on Venous System.

PURPOSE: Facial artery perforator flaps (FAPFs) are preferred for the repair of intraoral and peri-nasal defects because it is a convenient procedure with minimal donor-site morbidity. The purpose of this study was to investigate the anatomic features of FAPFs and present their clinical application in intraoral reconstruction. MATERIALS AND METHODS: Five cadaver specimens (10 sides) of the head and neck region and 90 clinical cases (90 sides) of neck dissection were analyzed to explore the facial venous drainage system of FAPFs. In addition, anatomic features of the facial artery and vein and the marginal mandibular branch of the facial nerve were investigated in cadaver specimens. Furthermore, the authors reviewed a series of 33 intraoral reconstruction cases using their designed FAPFs focusing on flap survival and facial venous drainage system types. RESULTS: Based on cadaveric and clinical observations, the facial vein drainage system was divided into 3 types: type A drained into the internal jugular vein (47%); type B drained into the external jugular vein (37%); and type C drained into the anterior jugular vein (16%). The mean distances from the facial artery to the vein at the region of the FAPF pedicle and tip were 2.79 ± 0.51 and 10.24 ± 0.70 mm, respectively. Most cases using the authors' designed FAPFs yielded satisfactory esthetic and functional outcomes, whereas 3 cases presented with venous congestion from type C facial vein drainage. CONCLUSION: This study improved the understanding of the anatomic features and clinical application of FAPFs in intraoral reconstruction. This FAPF design could be used to achieve superior intraoral defect reconstruction, and type C facial vein drainage might be a risk factor for flap survival.

Computer-aided design-based preoperative planning of screw osteosynthesis for type B condylar head fractures: A preliminary study.

OBJECTIVE: To investigate the clinical application of a new computer-aided design - (CAD) based planning method for the treatment of type B condylar head fractures without fragmentation. METHODS: A total of 13 adult patients (19 sides) with type B condylar head fractures were included in the study. In all cases, imaging was performed using cone bean computed tomography (CBCT) preoperative, and Digital Imaging and Communications in Medicine (DICOM) files were imported into Simplant 11.04 software. The fracture of the mandibular condyle was reconstructed by a three-dimensional reconstruction module, and the simulation of reduction was achieved according to the morphological characteristics. Preoperative design was performed based on the CAD technology, and the three-dimensional interface was used to determine the length, location, and orientation of the positional screw. Osteosynthesis was performed with a single positional screw according to the optimum direction assessed in the preoperative planning CBCT, and the result was confirmed with postoperative CBCT scans and clinical follow-up. RESULTS: Preoperative computer-aided design was able to predict the length, location, and direction of the positional screw. Postoperative CBCT results demonstrated that 12 cases (18 sides) were consistent with preoperative design with exception of one case (one side) due to unexpected rupture of the fragment. Six-month follow-up showed the condylar fractures were anatomically repositioned and that healing was excellent in 12 cases (18 sides) with minor displacement and resorption in one case (one side). Postoperative occlusion in all cases was excellent, and the maximum mouth opening improved from mean 1.2 cm preoperatively to a of mean 4.3 cm at 6 months postoperatively. The data for mandibular movements at 6 months postoperatively demonstrated the recovery of protrusion, without higher grade limitations for laterotrusion. In one case, there appeared to be mandibular deviation (<0.5 cm) with mouth opening. CONCLUSION: The new preoperative design provides relevant data for screw osteosynthesis to enhance the precision and effectiveness of open reduction and internal fixation type B condylar head fractures.

Accurate Evaluation of Cone-Beam Computed Tomography to Volumetrically Assess Bone Grafting in Alveolar Cleft Patients.

OBJECTIVE: The aim of this study was to investigate the accuracy of cone-beam computed tomography (CBCT) to assess the volume of bone graft in alveolar cleft patients. MATERIALS AND METHODS: Twelve patients of unilateral alveolar cleft were included in this study. All patients were taken CBCT preoperative and 1 week postoperative. The digital imaging and communications in medicine (DICOM) files were imported into Simplant software and three-dimensional (3D) reconstruction of the alveolar defect was achieved. With 3D volumetric measurements module, the volume of alveolar cleft was calculated preoperatively. During operation, the syringe compression method was adopted to calculate the actual amount of bone graft. One week postoperative, CBCT scan was performed again to measure the bone volume grafted to the defect. The volumetric ratio of the syringe compression method to preoperative CBCT assessment and the volume difference between syringe compression method and postoperative CBCT assessment were analyzed to evaluate the accuracy of CBCT measurement. RESULTS: The 3D structure of the alveolar cleft and the boundary of bone graft was clear from CBCT images. The estimated volume of alveolar cleft by preoperative CBCT scans was 1.06 ±â€Š0.09 cm, and the actual amount of bone graft determined by the syringe compression method was 1.51 ±â€Š0.12 cm. The ratio between the latter to the former was 1.43 ±â€Š0.07. The calculated volume of bone graft by 1-week postoperative CBCT scans was 1.53 ±â€Š0.11 cm, with no significant difference compared with the actual amount of bone graft (P > 0.05). CONCLUSIONS: CBCT was an accurate measurement to calculate the volume of alveolar defect and bone graft in alveolar cleft patients. Preoperative scans could aid in quantitatively determining the bone amount needed to adequately fill the bone defect, and the postoperative scans give accurate follow-up evaluation after surgery.

Extended Free Forearm Flap for Treatment of Temporomandibular Joint Pseudoankylosis.

Pseudoankylosis of temporomandibular joint (TMJ) is characterized by limited mouth opening and impaired mandibular mobility induced by pathologic factors outside the joint itself, usually leading to compromised speech, swallowing, and breath functions. Multiple surgical approaches or reconstructive procedures have been proposed to resolve the joint pseudoankylosis and restore the mandibular movement for these affected patients. Free forearm flap has been widely used in reconstruction for various congenital or acquired defects or deformities; however, this flap has been rarely employed for TMJ pseudoankylosis in the literature. Here, the authors reported that noma-induced TMJ pseudoankylosis was diagnosed and successfully treated by extended free forearm flap with length over 10 cm in a Chinese female patient.

[Clinical effect of functional repair of bilateral cleft lip in 66 patients].

PURPOSE: To explore the clinical effect of functional repair for bilateral cleft lip using modified Mulliken method. METHODS: Sixty-six patients with bilateral cleft lip were selected and assigned to receive modified Mulliken method. During the operation, the prolabium was kept as narrow "tie" shape, the orbicularis oris was anatomically repositioned, and the orbicularis oris ring was re-built. Vermilion tubercle was reconstructed with the lateral red vermillion. The nasal deformity was preliminarily repaired. and the nasal columella was elongated at the same time. RESULTS: All the patients were followed-up for 0.5-2 years, there was no "trisection upper lip". The symmetry and natural shape of Cupid's bow were obtained in more than 80% patients. The width of philtrum was similar to normal children. Full vermilion of the lips, moderate-size vermilion tubercles and good dynamic and static shape were obtained without whistle deformities. Normal width of nasal base and nostril symmetry were gained. The columella was elongated. Satisfactory contour of the nasal tip was achieved. CONCLUSIONS: Modified Mulliken method could functionally repair bilateral cleft lip and effectively correct nasolabial deformities. It is worthy of wide clinical application.

A new design of facial artery perforator flaps for the reconstruction of small- to medium-sized intraoral defects.

AIM: The aim of this study was to investigate the reliability and outcomes of a new design of facial artery perforator flaps, extending from the angle of the mouth to the border of the mandible, for the reconstruction of small- to medium-sized intraoral defects. PATIENTS AND METHODS: The technique had been used in 23 patients between February 2009 and August 2012. The locations of intraoral defects included the tongue, the floor of the mouth, the inferior gingival mucosa, and the sublingual gland. All flaps were monitored for complications including skin loss and ischemia. The functions of appearance, swallowing, and speech were assessed 6 months after operation with the University of Washington Quality of Life Questionnaire. RESULTS: All flaps presented with satisfactory results except for one, which demonstrated superficial tip necrosis that settled after conservative treatment. The follow-up period ranged from 6 to 12 months, and 1 patient died as a result of pulmonary metastasis, and 3 patients underwent second surgery because of local tumor recurrence (2patients) and cervical recurrence (1 patient). Nineteen patients were assessed with the University of Washington Quality of Life Questionnaire, and the mean (SD) scores of appearance, swallowing, and speech were 57.89 (14.45), 83.68 (19.98), and 81.58 (23.16), respectively. CONCLUSIONS: This design of facial artery perforator flaps could provide an efficient and cost-effective method for reconstruction of small- to medium-sized intraoral defects with a low surgical morbidity and satisfactory levels of quality of life.

Radial forearm free flap for reconstruction of a large defect after radical ablation of carcinoma of the tongue and floor of the mouth: some new modifications.

BACKGROUND: A modified radial forearm free flap was designed to rehabilitate function and to reduce the complications at both donor and recipient sites. METHODS: Between 2003 and 2007, 15 patients with infiltrating squamous cell carcinoma (T(3)-T(4)) of the tongue and/or floor of the mouth underwent hemiglossectomy and resection of the floor of the mouth with microvascular reconstruction using a modified radial forearm flap. The mean size of the forearm flap was 7.5 x 14 cm, and the de-epithelialized area was 7 x 6 cm, requiring no skin graft from the abdomen. Speech intelligibility tests were administered to test postoperative speech and the functional oral intake scale was applied to assess the postoperative swallowing function, and patients reconstructed with pectoralis major myocutaneous flap were used for comparison. RESULTS: All the flaps were successfully transferred. No obvious complications were found in either the oral-maxillofacial or forearm region. The speech intelligibility was better in the modified flap group (p < 0.01). An acceptable swallowing function was also achieved, although the difference was not significant (p > 0.05). CONCLUSIONS: The modified flap used for reconstructing large defects of the tongue and floor of the mouth might be a valid substitute for pectoralis major myocutaneous flap to improve the outcome in individuals with significant oral carcinoma.

Upregulation of vimentin and aberrant expression of E-cadherin/beta-catenin complex in oral squamous cell carcinomas: correlation with the clinicopathological features and patient outcome.

Oral squamous cell carcinoma is a challenging oncology problem. A reliable biomarker for metastasis or high-risk prognosis in oral cancer patients remains undefined. Using quantitative immunohistochemistry, we examined the expression of vimentin, E-cadherin, and beta-catenin in 83 oral squamous cell carcinoma patients, and the relationships between the expression of these markers and specific clinicopathological features were analysed. The high expression of vimentin was observed in 23 of 43 (53%) tumours from patients who eventually developed a recurrent tumour and was associated with recurrence and death (P<0.001 and <0.001, respectively). The decreased expression of E-cadherin was observed in 36 of 43 (84%) tumours from patients who eventually developed a recurrent tumour and was also associated with recurrence and death (P<0.001 and <0.001, respectively). Although no correlation between beta-catenin expression in whole-tumour sections and clinicopathological features was observed, decreased beta-catenin expression at the tumour invasive front was closely associated with recurrence and death (P=0.002 and 0.002, respectively). The expression of vimentin and that of E-cadherin were associated with survival and were independent prognostic factors in univariate and multivariate analyses. Our data show that the overexpression of vimentin was closely associated with recurrence and death in oral squamous cell carcinoma patients. The combination of the upregulation of vimentin and aberrant expression of E-cadherin/beta-catenin complexes at the tumour invasive front may provide a useful prognostic marker in oral squamous cell carcinoma.

[One-staged correction of alveolar cleft and lip and nasal deformities secondary to lip cleft].

OBJECTIVE: To investigate individualized one-staged correction of alveolar cleft and lip and nasal deformities secondary to lip cleft. METHODS: The alveolar cleft and lip and nasal deformities secondary to lip cleft were corrected in one stage. RESULTS: From 2004 to 2007, 37 cases were treated. 33 patients were treated successfully with primary healing in bony recipient area. Cancellous bone exposure happened in 3 cases. The wounds healed after debridement and drainage. The cosmetic results were satisfactory. CONCLUSIONS: One-staged correction of alveolar cleft and the lip and nasal deformities secondary to lip cleft can achieve good results.

[Odontoblast-like cell phenotype differentiation of cranial neural crest stem cell in vivo].

OBJECTIVE: To investigate the feasibility of tooth regeneration by seeding cranial neural crest stem cell (CNCSC) in vivo. METHODS: Cranial neural tubes, dissected from mouse E9 d, were explanted onto fibronectin-coated dishes. CNCSC emigrated from the explanted neural tubes, and were cultured in a free-serum medium containing modified DMEM/F12. CNCSC, induced by FGF8, BMP2, TGFbeta1 and dentin matrix non-collagen protein (DMNCP), were cultured with collagen/chitosan, and implanted into the subcutaneous part of immunodeficiency mouse. The expression of collagen I/dentin sialophosphoprotein (DSPP) was analyzed by immunocytochemistry. RESULTS: With the scaffolds destroying, columnar cells possessing polarized nuclei and matrix produced by cells were showed in some regions. Immunohistochemical staining demonstrated that collagen type I and DSPP were expressed throughout the cytoplasm and matrix produced by cells. CONCLUSION: By tissue engineering approach, our experiments further verify the odontoblast-like cell phenotype differentiation of CNCSC in vivo.

In vitro odontoblast-like cell differentiation of cranial neural crest cells induced by fibroblast growth factor 8 and dentin non-collagen proteins.

During tooth development, cranial neural crest (CNC) cells represent a population of pluripotent stem cells that give rise to various dental tissues. This study aimed to investigate whether CNC cells could differentiate into odontoblast-like cells by in vitro induction. CNC cells were isolated from explants of cranial neural tubes and cultured in serum-free Dulbecco's modified Eagle's medium (DMEM)/F12 medium which contained fibroblast growth factor 8 (FGF8) and dentin non-collagen proteins (DNCP). The initiation of controlled differentiation was determined using histological assays, and the expression of specific gene phenotypes was detected using immunocytochemical staining and reverse transcription--polymerase chain reaction (RT--PCR). The first branchial arch phenotype of the CNC cells demonstrated negative Hoxa2 expression and positive vimentin expression in the presence of 100 ng/ml FGF8. Following DNCP induction, the CNC cells became bipolar, demonstrated high alkaline phosphatase (ALP) activity, and formed mineralized nodules. In addition, the expression of DSPP, DMP1, and collagen type I confirmed the odontoblast phenotype. The results indicate that the tissue-specific cellular differentiation (odontoblast-like cells) of early-stage embryonic-derived cells (such as CNC cells) can be induced by adult extracellular matrix proteins (such as DNCP). CNC cells may be used as a valuable cell model for research on dental tissue differentiation and regeneration.

Chitosan-phosphorylated chitosan polyelectrolyte complex hydrogel as an osteoblast carrier.

To simulate extra-cellular matrix, a novel three-dimensional scaffold of polyelectrolyte complex (PEC) hydrogel as an osteoblast carrier was synthesized. First, chitosan, a natural glycosaminoglycan, was modified by phosphorylation to obtain a water-soluble phosphorylated chitosan (P-content: 10.7 mass%). The PEC hydrogel was then formed from equal volumes of 0.173 mass% phosphorylated chitosan in water and 1 mass% chitosan in 1% (V/V) acetic acid solution. Rat osteoblasts were seeded in the hydrogel. The PEC hydrogel had a three-dimensional hierarchically-porous structure and good cytobiocompatibility for osteoblasts in vitro. It is concluded that the PEC hydrogel is a promising material as an osteoblast carrier.

[Regulation of PTHrP in proliferation and differentiation of chondrocytes of condyle in fetal mouse].

OBJECTIVE: To investigate the regulatory mechanism of parathyroid hormone-related protein (PTHrP) in proliferation and differentiation of chondrocytes of condyle in fetal mouse. METHODS: Chondrocytes of condyle in fetal mouse were separated and cultured in vitro, the influence of PTHrP on proliferation and differentiation was observed. RESULTS: After two weeks' culture in 0.01 nmol/L, 0.1 nmol/L, 1 nmol/L, 10 nmol/L human PTHrP, there was significant difference in the number of cartilage nodule formed between experiment group and control group (P<0.05), and there was no significant difference in 0.01 nmol/L group (P>0.05). Alkaline phosphatase (ALP) activity was significantly intensified in experiment group and control group (P<0.05). Meanwhile, it was found that this function of promotion was lessened after anti-PTHR antibody used. CONCLUSION: It can be seen that PTHrP, via its receptor, can promote proliferation and differentiation of chondrocytes of condyle, which resemble its modulation mechanism in epiphyseal growth plate cartilage intramembrane in mandibule.

[In vitro study on cranial neural crest differentiating into ectomesenchymal cell of the first branchial arch by FGF-8].

OBJECTIVE: To investigate the effects of FGF-8 on cranial neural crest cell (CNCC) differentiating into ectomesenchymal cell of the first branchial arch, and determine the appropriate dose and stage of CNCC exposure to FGF-8. METHODS: Cranial neural crest explants were cultured in free-serum medium containing modified DMEM/F12 and different doses of FGF-8. The differentiation type of CNCC were determined by in situ hybridization for Hoxa2 and immunocytochemistry for vimentin. RESULTS: Pre-emigrating CNCC demonstrated the negative Hoxa2 stain and positive vimentin stain after treated by 100 ug/FGF-8. Both post-emigrating CNCC group and control group were positive for Hoxa2 and vimentin stain. CONCLUSIONS: On the early stage of CNCC emigration, the first branchial arch phenotype of CNCC could be induced by FGF-8. This experiment could provide in vitro model for study on the mechanism of tooth-jaw regeneration.

[In vitro culture and biological characteristics of cranial neural crest stem cell].

OBJECTIVE: According to development biology, cranial neural crest stem cell (CNCSC) can differentiate into precursor cells of tooth, jaw and peripheral nerve system, but in vitro study is less reported. In the present study, CNCSC were dissociated and cultured in vitro, and the biological characteristics of CNCSC was investigated. METHODS: Cranial neural tubes, dissected from mouse E9d, were explanted onto fibronectin-coated dishes. CNCSCs emigrated from the explanted neural tubes, cultured in a serum-free medium containing modified DMEM/F12. Biological characteristics of CNCSC were detected by morphology, nuclear labeled with BurdU and immunocytochemistry. RESULTS: Fibroblast-like CNCSCs demonstrated the characteristics of stem cell, such as clonality, self-renewal and multipotentiality. The result of immunocytochemical stain showed that CNCSC expressed HNK-1 antigen. CONCLUSION: CNCSC were cultured successfully, providing a experimental basis for study on tooth/jaw-like differentiation of CNCSC in vitro, especially providing a cell source for investigating tooth/jaw regeneration.

[The correlation between neck lymphy node metastasis and matrixmetalloproteinase-2 expression at the invasive tumor front of oral squamous cell carcinomas].

OBJECTIVE: To explore the correlation between neck lymph node metastasis and matrix metalloproteinase-2 expression at the invasive tumor front of oral squamous cell carcinomas(OSCC). METHODS: Immunohistochemistry LsAB technique was used to observe the expression of MMP-2 at the invasive tumor front and center of OSCC, and the correlation between the expression of MMP-2 in OSCC and neck lymph node metastasis were respectively analyzed by statistics. RESULTS: The results demonstrated that MMP-2 existed in all 71 cases, which the expression of MMP-2 at the OSCC front was more significant than that of MMP-2 at the OSCC center (P < 0.01), and related to neck lymph node metastasis (P < 0.05). CONCLUSION: The expression of MMP-2 at the OSCC front could be considered as an index of judging the present of neck lymph node metastasis of OSCC.