RESUMO
Bronchopulmonary dysplasia(BPD)is a chronic pulmonary disease related to preterm neonatal.The pathogenesis of BPD hasn′t been clear now.But we have already known extracellular matrix remodeling has played an important role in alveoli dysplasia.We have found epigenetics has participated in extracellular matrix remodeling.There is a strict balance between the composition and decomposition of the ECM under the physiology state.However the ECM will reconstruct when its component change, which would influence the normal physiology process and lead to the disease.The review describes DNA methylation′s and microRNAs′ functions in extracellular matrix remodeling of BPD.This may help us understand the pathogenesis of BPD, and may offer some new methods to prevent or cure BPD.
RESUMO
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.