Rapamycin/sodium hyaluronate binding on nano-hydroxyapatite coated titanium surface improves MC3T3-E1 osteogenesis.

Endosseous titanium (Ti) implant failure due to poor biocompatibility of implant surface remains a major problem for osseointegration. Improving the topography of Ti surface may enhance osseointegration, however, the mechanism remains unknown. To investigate the effect of modified Ti surface on osteogenesis, we loaded rapamycin (RA) onto nano-hydroxyapatite (HAp) coated Ti surface which was acid-etched, alkali-heated and HAp coated sequentially. Sodium hyaluronate (SH) was employed as an intermediate layer for the load of RA, and a steady release rate of RA was maintained. Cell vitality of MC3T3-E1 was assessed by MTT. Osteogenesis of MC3T3-E1 on this modified Ti surface was evaluated by alkaline phosphatase (ALP) activity, mineralization and related osteogenesis genes osteocalcin (OCN), osteopontin (OPN), Collagen-I and Runx2. The result revealed that RA/SH-loaded nano-HAp Ti surface was innocent for cell vitality and even more beneficial for cell osteogenesis in vitro. Furthermore, osteogenesis of MC3T3-E1 showed significant association with the mammalian target of rapamycin (mTOR) phosphorylation by RA, which required further study about the mechanism. The approach to this modified Ti surface presented in this paper has high research value for the development of Ti-based implant.

[Preliminary study on transformation of the biological function of the cryopreserved osteoblasts cultured in vitro].

OBJECTIVE: To culture and amplify the young rabbit's bone marrow stromal cells (BMSCs) in vitro, and to observe the effect of hypothermia on the cells' growing behavior and biological function. METHODS: BMSCs were acquired from the rabbit' tibia bone marrow and induced to mature osteoblasts in vitro. The cultured cells growing well in vitro were preserved in liquid nitrogen. The anabiotic cells having cryopreserved for 1 week were chosen as the experimental group, and the routine 7th generation as the control group. Their biological function in comparion by the examination of morphological changes, cells' proliferation ability, colone forming ratio, synthesis ability of ALP and protein, mineralized nodes forming ability were observed. RESULTS: As contrast to the control groups, the anabiotic cells also grew and proliferated well in vitro except a little more slowly than before. They had the similar general shape in all the time segments, but a little differences in cells' ultrastructure. The experimental groups also had the typical characters of mature osteoblasts, and high abilities of the synthesis of ALP and proteins. The statistic data showed that these two groups had no significant difference (P > 0.05). CONCLUSION: The cryopreserved osteoblasts had the same biological functions and the similar growing behaviors as before. These results suggest that it is practical to use the cryopreserved osteoblasts for further study on bone tissue engineering.

[Surgical treatment of obstructive sleep apnea hypopnea syndrome after velopharyngeal ring ligation procedure].

PURPOSE: To evaluate the effect of removal of ligation thread combined adenoidectomy in the treatment of obstructive sleep apnea hypopnea syndrome (OSAHS) after velopharyngeal ring ligation procedure (VRLP). METHODS: The upper airway was examined with dynamic fiberoptic pharyngoscope in six patients with cleft palate who were diagnosed as OSAHS by polysomnography(PSG) after VRLP. All the patients underwent removal of ligation thread and adenoidectomy. Three months after operation, they were recalled back and were examined with polysomnography and dynamic fiberoptic pharyngoscope. The preoperative and postoperative PSG data were analysed with t test and chi-square test to determine the statistical differences. RESULTS: In patients with OSAHS after VRLP, a ring scar was observed on the upper airway at the soft palate level and a remarkable narrow nasopharyngeal meatus was found mainly because of adenoidal hypertrophy. After removal of ligation thread and adenoidectomy, no velopharyngeal incompetence was found, the upper airway morphology was smooth, respiration disorder during sleeping was completely disappeared and sleep architecture became normal. There were significant differences between preoperative and postoperative PSG data. CONCLUSION: Removal of ligation thread combined adenoidectomy was an effective treatment for OSAHS after VRLP.

[The experimental study of cryopreserved osteoblasts combined with BGC repairing mandibular defects in rabbits].

OBJECTIVE: The purpose of this study was to observe the biological characteristics of cultured Periosteal-derived Osteoblasts (POBs) preserved in liquid nitrogen in vitro, and to preliminarily study the osteogenetic capability of bioactive glass ceramic (BGC) combined with POBs. METHODS: The cryopreserved cells were cultured in DMEM medium and examined by morphological and histological assay. The POBs growing well in vitro were seeded into the porous BGC materials. A week later, the combined materials were implanted into the bone defects of rabbits' mandibular, the control groups were implanted into the single BGC (no cells). After 2, 4, 8, 12 weeks of operation, the specimens were respectively excised and examined by X-ray and histological chemistry. RESULTS: The cryopreserved POBs grew well in vitro and also had the tipical characteristics of mature osteoblasts. Cultured with BGC materials, the cells could attach, grow and proliferate well on the surface of most endoporous. After 4 weeks of operation, the transplanted osteoblasts began to form new osteoid or bone tissue in most pores of implanted BGC, and the bone defects were repaired better and earlier. CONCLUSION: It was practical to use the cryopreserved osteoblasts for further study on bone tissue engineering. It suggested that the "life active" bone would get more application and play a more important role in bone restoration and reconstruction.