BACKGROUND: Artificial humeral head replacement is an effective method for the treatment of complex proximal humeral fractures, which has received good results in relieving pain. However, the final functional recovery is unpredictable. OBJECTIVE: To compare biomeshanical stability between anatomical and overlapping reconstruction of the greater tuberosity in cadaveric humeral head replacement models.METHODS: Eight pairs of fresh-frozen shoulder cadavers (16 shoulder joints) were match-paired into two groups. Standardized humeral head replacement procedure was performed in all specimens, and anatomical and overlapping reconstruction of thegreater tuberosity was adopted in each group respectively. For overlapping group, the greater tuberosity was reattached to the proximal humeral shaft in an overlapping style, which was achieved by an additional 5 mm bone osteotomized from the medial cortex of the humeral diaphysis. Custom mounting apparatus and fixation jigs were designed for designated shoulder motion.RESULTS AND CONCLUSION: When the shoulder was external rotated to neutral position, the mean displacement of greater tuberosity in the anatomical reconstruction group was smaller than that of the overlapping reconstruction group (P < 0.05). When the gleno-humeral joint was elevated to 30～ and 60～ forward flexion (accounting for 45° and 90° shoulder forward flexion), there was no significant difference of greater tuberosity displacement between the anatomical group and overlapping group. The findings demonstrated that, although overlapping reconstruction can increase the bone healing area between the greater tuberosity and the humeral diaphysis, there may be some loss in mechanical stability as the trade-off. Even though we strictly follow the standardized postoperative rehabilitation protocol after humeral head replacement, prominent displacement between the greater tuberosity relative to the humeral diaphysis was detected. Accordingly, postponing of the postoperative rehabilitation program after humeral head replacement for a decent period may improve tuberosity healing.

Objective To investigate the analgesic efficacy of intrathecal injection of RC-13,a competitive kinesin superfamily protein 17 antagonist,in a mouse model of bone cancer pain.Methods Forty male C3H/HeJ mice,aged 6-8 weeks,weighing 20-25 g,were randomly divided into 5 groups (n=8 each): sham operation group (group S); bone cancer pain + 5 μl dimethyl sulfoxide (DMSO) group (group R0); bone cancer pain + 2.5 μg RC-13 group (group R1); bone cancer pain + 5 μg RC-13 group (group R2) and bone cancer pain + 10 μg RC-13 group (group R3).In groups R0-3,bone cancer pain was induced by implantation of α-min-imal essence medium (α-MEM) containing osteosarcomaNCTC 2472 cells into the intramedullary space of right femur.In group S,culture medium α-MEM containing no cancer cell was injected instead.10％ DMSO 5 μl and RC-13 2.5 μg/5 μl,5μg/5μ1 and 10 μg/5 μ1 dissolved in 10％ DMSO were injected intrathecally in groups R0-3,respectively,once a day for 3 consecutive days starting from 14th day after inoculation of the tumor cells.Pain behavior was assessed by the paw withdrawal mechanical threshold (PWMT) and spontaneous lifting times (SLTs) measured at 1 day before inoculation and at 3,5,7,10,14 days after inoculation.The same tests were also performed at 1,3,5 and 7 days after administration in groups R0-3.Results Compared with group S,PWMT was significantly decreased and SLTs were increased at 7-14 days after inoculation in the other groups (P ＜ 0.05).Compared with group R0,PWMT was significantly increased and SLTs were reduced at 1 day after administration in group R1,at 1and 3 days after administration in group R2,and at 1,3 and 5 days after administration in group R3 (P ＜ 0.05).Compared with group R1,PWMT was significantly increased and SLTs were reduced at 3 days after administration in group R2,and at 1,3 and 5 days after administration in group R3 (P ＜ 0.05).Compared with group R2,PWMT was significantly increased and SLTs were reduced at 1 and 3 days after administration in group Rs (P ＜ 0.05).Conclusion Intrathecal RC-13,a competitive kinesin superfamily protein 17 antagonist,has a good analgesic efficacy in a mouse model of bone cancer pain and the efficacy is dose-dependent.

BACKGROUND: Diabetes can lead to many complications. Of them, retinopathy is a common type. To explore the effect of erythropoietin in diabetic retinopathy, it is necessary to establish an animal model of similar pathologic features and high reproducibility in clinical retinal neovascularization.
OBJECTIVE: To investigate the protective effect of vitreous cavity injection of erythropoietin on optic nerve of rats with diabetic retinopathy.
METHODS: Rat models of diabetic retinopathy were established and injected with erythropoietin through vitreous space for 14 consecutive days. Results were compared between the model and normal control groups.
RESULTS AND CONCLUSION: (1) Transmission electron microscope: compared with the model group, retinal ganglion cel nucleus presented uniform red; cel membrane was intact; endoplasmic reticulum exhibited slight swel ing. A smal number of vacuoles were found in mitochondria around the nuclei. (2) Western blot assay and RT-PCR: compared with the model group, Caspase-3 and Bax protein expression was lower in the erythropoietin group (P < 0.05). Caspase-3 protein and Bcl-2 protein expression was significantly higher in the erythropoietin group than in the model group (P < 0.05). Significant differences in nuclear factor κB and Survivn gene expression were detected between the model and erythropoietin groups (P < 0.05). (3) Results verified that vitreous cavity injection of erythropoietin had neuroprotective effect on rats with diabetic retinopathy, which may be associated with the inhibitory effect on apoptosis.