Objective To study the phenomena and the related mechanisms of malignant transformation of dermis derived multipotential stem cells in vitro . Methods Clonal populations of dermal multipotential stem cells were passaged sequentially in vitro , and the subcutaneous inoculation of cells in nude mice was used for observation of the tumor formation. The transcript profiles of the transformed cells were analyzed by DNA microarray technique. Results Dermal multipotential stem cells underwent spontaneous malignant transformation after serial subculture in vitro . Cells grew out of control, and chromosome number was abnormal. After cells were inoculated subcutaneously into BALB/c nu/nu athymic mice, tumors characterized by fibrous histiocytoma were produced. Immunohistochemistry showed that there were different cell populations for the expression of vimentin, cytokeratin, S 100, and ? smooth actin. Detection by DNA microarray technique revealed that the transformed cells expressed multilineage transcripts, indicating that the transformed cells might have the multipotency. Among the differentially expressed genes in transformed cells, most of the up regulated genes were related to the proliferation process, but most of the down regulated genes were growth factors and their receptors. The enhanced expression of the c ki ras gene and its relevant molecules may play important roles in the transformation process. A candidate gene with unknown functions related to the stem cell proliferation was also preliminarily identified. Conclusion Dermal multipotential stem cells can undergo spontaneous malignant transformation in vitro . Further studies of the mechanisms of this process at the molecular level may have significance both in stem cell application and in tumorigenesis.

Objective To investigate the clinical value of surgical navigation system for the foreign bodies removal from deep space of oral,maxillofacial and cervical regions.Methods The data of 64 patients with foreign body removal treated in the department of stomatology of this hospital during 2014-2021 were retrospectively analyzed,in which the control group (n=52) received the traditional surgical treatment for foreign body removal,and the observation group (n=12) received surgical navigation system guided foreign body removal from deep space of oral,maxillofacial and cervical regions.The surgery-related indexes and oc-currence situation of complications were compared between the two groups.Results The constituent ratio of males in the two groups was higher than that of females,the foreign bodies were common in oral and maxillo-facial regions,which was dominated by nonmetal foreign bodies.The foreign bodies in the observation group all were successfully removed,which in 96.15％ of patients in the control group were successfully removed. Compared with the control group,the volumes of intraoperative blood loss and postoperative drainage in the observation group were decreased (P<0.05),the operation time and hospitalization duration were decreased,the operation incision length was shortened,and the differences were statistically significant (P<0.05).The incidence rate of complications in the observation group was significantly lower than that in the control group (0 vs. 32.69％,P<0.05).Conclusion The use of surgical navigation system guidance for foreign body re-moval from deep space of oral,maxillofacial and cervical regions could precisely locate the position of the for-eign body,help to shorten the operation time,decrease the wound length,improve the prognosis of the pa-tients.

BACKGROUND:The content of serum thrombin in patients with osteoarthritis is significantly higher than that in normal individuals,and thrombin can induce inflammatory degeneration of rat chondrocytes,suggesting that inhibiting the function of thrombin may become a method for treating osteoarthritis.Celecoxib is a common therapeutic drug for the clinical treatment of osteoarthritis.It is not yet known whether it improves chondrocyte degeneration by inhibiting the activity of thrombin. OBJECTIVE:To investigate the effect of celecoxib on thrombin-induced degeneration of rat chondrocytes. METHODS:Thrombin levels in the serum of osteoarthritis patients and normal individuals were detected by an ELISA kit.Primary chondrocytes of neonatal Sprague-Dawley rats were isolated,and all experiments were performed with cells from passage one.Chondrocytes were randomly divided into three groups:control group,thrombin group,and celecoxib group.The cell morphology of the three groups was observed under an inverted microscope,and an Edu kit was used to detect the cell proliferation.qRT-PCR was used to detect the expression of extracellular matrix components(aggrecan,elastin,cartilage oligomeric matrix proteins),inflammatory factors(interleukin-1,interleukin-6,and tumor necrosis factor-α),and chemokines(monocyte chemotactic protein 2,monocyte chemotactic protein 7,granulocyte chemotactic protein 6).The expression of type 2 collagen α1 was detected by immunofluorescence.Western blot method was used to detect the expression of catabolic metabolism genes,such as matrix metalloproteinase 9,matrix metalloproteinase 13,and cyclooxygenase 2. RESULTS AND CONCLUSION:Patients with osteoarthritis had higher levels of thrombin in the serum compared with normal individuals.Under the microscope,celecoxib was found to significantly inhibit fibroid changes in chondrocytes.Compared with the thrombin group,celecoxib inhibited the proliferation of chondrocytes.The downregulation of extracellular matrix gene expression,such as type II collagen α1,in the thrombin group was inhibited by celecoxib(P<0.05).Thrombin promoted the expression of inflammatory factors(interleukin-1,interleukin-6,and tumor necrosis factor-α),chemokines(monocyte chemotactic protein 2,monocyte chemotactic protein 7,granulocyte chemotactic protein 6),as well as catabolic genes(matrix metalloproteinase 9,matrix metalloproteinase 13,and cyclooxygenase 2),and under the intervention of celecoxib,the expression of these genes could be downregulated(P<0.05).Overall,these findings indicate that celecoxib inhibits the pro-inflammatory effects of thrombin and thereby ameliorates chondrocyte degeneration in rats.