[Protective effect and mechanisms of dihydromyricetin on PC12 cells induced by oxidative injury].

OBJECTIVE: To study the protective effect and possible mechanisms of Dihydromyricetin(DMY)on PC12 cells injury in- duced by sodium nitroprusside( SNP). METHODS: SNP toxicity cellular model was established using PC12 cells treated with SNP. Cell via- bility was determined by MTT assay. The apoptosis of treated cells was detected by Hoechst Staining. Effect of DMY on accumulation of ROS in PC12 cells induced by SNP was detected by fluorometric analysis. The pathways involved were studied by kinase specific inhibi- tors; The level of phosphorylated Akt and ERK1/2 was detected by Western blot with specific phosphor-antibodies. RESULTS: SNP in- duced the apoptosis of PC12 cells in a dose-dependent manner. DMY dose-dependently protected PC12 cells from injury induced by SNP. Hoechst staining indicated that SNP decreased the number of viable cells and induced shrinkage and aggregation of the nucleus, whereas DMY attenuiated the toxic effects of SNP. The level of ROS induced by SNP in PC12 cells was decreased gradually by DMY. PI3K specific inhibitor LY294002 and the MAPK pathway specific inhibitor PD98059 attenuated the protective effect of DMY on SNP-induced injury of PC12 cells. However, the effect of DMY could be blocked by LY294002 and PD98059 respectively. CONCLUSION: DMY possesses protective effect against apoptosis induced by SNP in PC12 cells,and its mechanisms may be partially related with Akt and ERK1/2 signaling.

Reconstruction of orbital defect in rabbits with composite of calcium phosphate cement and recombinant human bone morphogenetic protein-2.

BACKGROUND: Calcium phosphate cement (CPC) is a biocompatible and osteoconductive bone substitute, and recombinant human bone morphogenetic protein-2 (rhBMP-2) has strong osteoinductibility, therefore we developed a composite bone substitute with CPC and rhBMP-2 and evaluate its reconstruction effect in rabbit orbital defect. METHODS: Thirty-six rabbits were randomly divided into two groups and a 5 mm × 5 mm × 2 mm bone defect in the infraorbital rim was induced by surgery in each orbit (72 orbits in all). The orbital defects were treated with pure CPC or composite of CPC and rhBMP-2. The osteogenesis ability of different bone substitute was evaluated by gross observation, histological examination, histomorphometrical evaluation, compressive load-to-failure testing, and scanning electron microscope (SEM). RESULTS: Gross observation showed that both bone substitutes were safe and effective for reconstruction of orbital defect. However, histological examination, histomorphometrical evaluation and SEM showed that CPC/rhBMP-2 group had faster speed in new bone formation and degradation of substitute material than CPC group. Compressive load-to-failure testing showed that CPC/rhBMP-2 group had stronger compressive strength than CPC group at every stage with significant difference (P < 0.05). CONCLUSION: Composite of CPC/rhBMP-2 is an ideal bioactive material for repairing orbital defect, with good osteoconductibility and osteoinductibility.

[Study of surgical techniques of divided nevus of eyelids].

OBJECTIVE: To investigate the surgical techniques of divided nevus of the eyelids with different locations and sizes. METHODS: Retrospective observational case series. Thirty cases (30 eyes) of divided nevus of the eyelids in Zhongshan Ophthalmic Center from July 1997 to November 2006 were retrospectively reviewed. There were three different surgical methods. Excision of the nevus and direct suture after excision in 3 cases. Excision of the nevus and free skin graft transplantation in 5 cases. Excision of the nevus and transfer of skin flap, which included a two stages reconstruction, was performed in 22 cases. The upper or lower eyelid was treated first and another eyelid was treated after three months. Lacrimal punctum and lacrimal canaliculus were excised if they were involved in 8 cases among 22 cases. RESULTS: The mean follow-up time was 60 months (ranging from 2 years to 11 years). Only one case recurred after two years during follow-up and was excised after five years. Pathologic examination indicated malignant transformation. Excision with histopathological control was performed and the nevus did not recur during follow-up time. Recurrence or malignant transformation did not occur in other cases. Aesthetical results of skin flap transplantation were better than skin graft transplantation. CONCLUSIONS: The results of two stages reconstruction and transfer of skin flap after excision of the divided nevus are better than free skin graft transplantation. Close observation is required after excision of the divided nevus for early detection of malignant transformation.

[Clinical characteristics of moderate and severe Marcus-Gunn jaw-winking synkinesis and its surgical treatment].

OBJECTIVE: To investigate the clinical characteristics of moderate and severe Marcus-Gunn jaw winking synkinesis and it surgical management. METHODS: Thirty-three patients with Marcus-Gunn syndrome were enrolled from 1997 to 2003 in Zhongshan Ophthalmic Center. The clinical characteristics were analyzed based on the records. Unilateral levator excision and frontalis flap suspension were performed for the correction of ptosis and the results were analyzed. RESULTS: The follow-up period varied from 1 to 6 years. Sixteen patients were male and 17 were female. The left eye was involved in 22 patients and the right eye in 11 patients. There was no family history. The amount of ptosis in each patient was more than 2 mm. At the end of observation, good results were achieved for ptosis correction in 26 (87%) of 30 patients, fair results in 3 (10%) patients. CONCLUSIONS: The ptosis of patients with moderate and severe Marcus-Gunn syndrome needs to be treated surgically. Unilateral frontalis flap suspension combined levator excision can correct ptosis very well for patients with moderate and severe Marcus-Gunn syndrome.

[Reconstruction of orbital floor defect with polylacticglycolide acid/recombinant human bone morphogenetic protein 2 compound implanted material in sheep].

OBJECTIVE: To study the effect and safety of polylacticglycolide acid copolymer (PLGA) and recombinant human bone morphogenetic protein 2 (rhBMP-2) as implanted biomaterials for reconstruction orbital floor defects in sheep and find the relationship between implant materials degradation and orbital floor defects restoration. METHODS: Nine sheep (eighteen eyes) with orbital floor defect were divided into three groups randomly. Group A was the control without treatment. Group B was treated with PLGA and group C was received PLGA/rhBMP-2. Cosmetic appearances and complications were observed after surgery. CT scan, 3D reconstruction, defect area measurement and histological examination were performed on a week, three months and six months after operation. RESULTS: No complication was observed. The CT examinations showed that orbital floor defect in group C was almost disappeared by six months, however in group A and group B only partially orbital floor defect was repaired. Histological examinations showed that all materials were absorbed on six months. The orbit defects in group A were replaced by fiber tissue. The defect areas in group B were consisted of bone tissue in the peripheral and fiber tissue in the center. In group C the reconstructed areas were replaced by bone tissue, loose connective tissue and mucosal epithelia layers. CONCLUSION: The thick of 0.5 mm PLGA/rhBMP-2 sheet is a good substitute material of bone graft and may be used for orbital fracture defect reconstruction in clinic in the future.