BACKGROUND:The use of bio-membrane guided bone regeneration in maxilary sinus augmentation is a research hotspot in implantology at present. OBJECTIVE:To investigate the osteogenic effect of guided bone regeneration in maxilary sinus augmentation using colagen membranes. METHODS:The first maxilary molars of nine adult female beagle dogs were extracted and ful-thickness flap was reflected bilateraly, then the sinus floors were lifted with simultaneous implantation. Bio-Oss was placed into the new space under the sinus membrane. On the experimental side in each dog, the bio-membrane covered the osteotomy window. On the control side, the flap was sutured directly, and was not covered by bio-membrane. Two animals were sacrificed at 4, 12, and 24 weeks after surgery, respectively. Gross observation, biomechanical testing and histological examinations were performed. RESULTS AND CONCLUSION: In gross view, new bone formation was observed in al maxilary sinuses. The pul-out force increased with time. At week 24, a significant difference in the pul-out force was noted between the two groups (P < 0.05). Histomorphbomatrical analysis showed much more new caluses at the experimental group than the control group at weeks 12 and 24 after surgery (P < 0.05). The bio-membrane guided bone regeneration has a better effect on new bone formation in the sinus augmentation.

objective To explore a new method of repairing skin defects complicated with fracture and tendon rupture at the middle and distal sections of the second to fifth fingers. Methods The reversed dorsal metacarpal island flap was designed to be pedicled on the digital proper artery-common digital artery-fingerweb artery-dorsal metacarpal artery-cutaneous branch of dorsal metacarpal artery.In repairing digital palmar skin defects,after the flap was dissected,the proximal incision was extended along the direction of dorsal metacarpal nerve to harvest an enough length of the nerve so that the dorsal metacrppal nerve can be anastomosed with the digital proper nerve to restore the sensation of finger pulp.From the June 2003 to March 2009,the flap was used to repair 26 fingers in 24 patients with middle and distal digital skin defects complicated with fracture and tendon rupture.They were 17 men and 7 women,aged from 16 to 63 years (average,37 years).There were 15 cases of palmar skin defect and 9 cases of dorsal skin defect.In the 2 cases of combined tendon defects,a section of the extensor tendon of index(or little) finger was dissected together with the flap to repair the tendon rupture. Results The areas of the flap ranged from 3.1 cm ×1.6 cm to 6.0 cm × 4.0 cm.The flaps survived in all 24 cases without any vascular crisis.Twenty-two patients obtained an average follow-up of 14 months (from 4 to 32 months) but 2 were lost to the follow-up.The flaps were fine in texture,colour and appearance.The finger pulps appeared full and recovered sensations of pain and temperature.The average two-point discrimination was 7.5 mm (from 5 to 9 mm).Sensory function evaluation revealed an outcome of S3 + ～ S4.Tendon adhesion occurred in 4 cases which recovered digital function following secondary lysis 3 to 6 months postoperation. Conclusion Application of the reversed dorsal metacarpal island flap pedicled on the digital proper artery is a good way to repair skin defects complicated with fracture and tendon rupture at the middle and distal sections of the second to fifth fingers.

With the continuous development of maxillary sinus floor elevation technology, the osteogenesis mechanism of maxillary sinus floor elevation has always been a concern of scholars. The membrane of the maxillary sinus is an indispensable physiological structure in the process of space osteogenesis under the sinus floor after elevation of the sinus floor. In recent years, the role of the maxillary sinus floor mucosa in sinus floor space osteogenesis has been a research hotspot. Recent studies have found that the maxillary sinus floor membrane plays a role as a natural biological barrier membrane in the process of sinus floor space osteogenesis after maxillary sinus floor elevation; in addition, it has the ability to undergo osteogenesis. It has also been found that maxillary sinus membrane stem cells (MSMSCs) derived from the maxillary sinus floor membrane have characteristics of mesenchymal stem cells, which can differentiate into osteoblasts and participate in sinus floor space osteogenesis after maxillary sinus floor elevation. New studies have also found that small RNAs such as microRNAs, long noncoding RNAs and circular RNAs can regulate the osteogenic differentiation of MSMSCs, which may be important biological targets for promoting osteogenesis in the sinus floor space. In this paper, the relationship between the maxillary sinus floor mucosa and bone formation after maxillary sinus floor elevation, the barrier and osteogenic function of the maxillary sinus floor mucosa, the sources of osteoblasts involved in osteogenesis of the sinus floor space, and the molecular regulatory mechanisms of stem cells derived from maxillary sinus mucosa will be elucidated step by step.

Objective: To detect the expression level of miR-27a during the osteogenic differentiation of beagle maxillary sinus membrane stem cells (MSMSCs) and explore the role of miR-27a in the osteogenic differentiation of MSMSCs. Methods: Beagle MSMSCs were cultured in vitro. The expression level of miR-27a was detected via RT-PCR after an osteogenic inductive culture was prepared. The mRNA expression levels of Runx2 and OPN were examined via RT-PCR, and the protein expression levels of Runx2 and OPN were examined via Western blot after the cells were transfected with pre-miR-27a or anti-miR-27a. Finally, osteoprogenitor cells transfected with pre-miR-27a were composited with Bio-Oss particles and subcutaneously implanted into nude mice to form ectopic bone formation models, and then the inhibition of bone formation from miR-27a was observed in vivo. Results: The expression level of miR-27a in the beagle MSMSCs decreased after osteogenic inductive culturing. The relative miR-27a levels were significantly decreased at day 1 (t=3.795, P=0.023), day 3 (t=4.493, P=0.011), day 7 (t=11.591, P < 0.001), day 14 (t=12.542, P < 0.001), and day 21 (t=5.621, P=0.008) compared with day 0. In addition, the expression levels of Runx2 mRNA (t=4.923, P=0.007) and protein (t=4.425, P=0.008) were reduced after the cells were transfected with pre-miR-27a. The expression levels OPN mRNA (t=5.253, P=0.006) and protein (t=5.132, P=0.006) were also reduced. In contrast, the mRNA expression levels of Runx2 (t=3.925, P=0.013) and OPN (t=3.712, P=0.019) were increased after the cells were transfected with anti-miR-27a, and bone formation was observed after the subcutaneous implantation of beagle MSMSCs composited with Bio-Oss in nude mice. Nevertheless, ectopic bone formation was inhibited by pre-miR-27a-transfected beagle MSMSCs composited with Bio-Oss (t=7.219, P=0.0020). Conclusion MiR-27a negatively regulates the osteogenic differentiation of MSMSCs.

Objective: To investigate the osteogenic properties of maxillary sinus membrane stem cells (MSMSCs). Methods : Beagle maxillary sinus mucosa was collected, immunomagnetic bead method was applied for isolation of CD146+ cells, and MSMSCs were harvested and cultured from the canine maxillary sinus floor mucosa. The levels of the cell surface antigens CD44, CD146, and CD34 were determined at passage one by flow cytometry. Cells at passage one were cultured in basal medium and osteogenic inductive medium. Real-time PCR, immunohistochemical staining, alkaline phosphatase activity, alizarin red staining and Von Kossa staining were used to investigate the osteogenic properties in vitro. Results: The canine MSMSCs were cultured successfully. The results of flow cytometry were positive for CD146 and CD44 expression but negative for CD34 expression. The relative mRNA expression of runt-related transcription factor 2 (RUNX2) (t = 14.44,P < 0.001), osteopontin (OPN) (t = 7.85,P = 0.001) and alkaline phosphatase alkaline phosphatase (t = 14.27,P < 0.001) was apparently higher in the osteoinductive medium group than in the basal medium group, the differences in relative mRNA expression between the groups were significant. The protein levels of RUNX2 and OPN increased in the osteoinductive medium group. The alkaline phosphatase activity of the MSMSCs increased when the cells were cultured in osteoinductive medium; the activity increased to a level that was significantly higher than that in basal medium, particularly at days 3 (t = 8.79, P < 0.001), 7 (t = 9.75,P < 0.001), 14 (t = 12.14,P < 0.001), 21 (t = 19.62,P < 0.001) and 28 (t = 17.53,P < 0.001). Obvious mineralized nodules were observed by alizarin red staining or Von Kossa staining. Conclusion Maxillary sinus membrane stem cells exhibit osteogenic ability.