The organization, regulation, and biological functions of the synaptonemal complex / 亚洲男科学杂志(英文版)

The synaptonemal complex (SC) is a meiosis-specific proteinaceous macromolecular structure that assembles between paired homologous chromosomes during meiosis in various eukaryotes. The SC has a highly conserved ultrastructure and plays critical roles in controlling multiple steps in meiotic recombination and crossover formation, ensuring accurate meiotic chromosome segregation. Recent studies in different organisms, facilitated by advances in super-resolution microscopy, have provided insights into the macromolecular structure of the SC, including the internal organization of the meiotic chromosome axis and SC central region, the regulatory pathways that control SC assembly and dynamics, and the biological functions exerted by the SC and its substructures. This review summarizes recent discoveries about how the SC is organized and regulated that help to explain the biological functions associated with this meiosis-specific structure.

[Clinical observation on extensor weakness after total knee arthroplasty for severe flexion deformity knees].

OBJECTIVE: To find out the reasons of extensor weakness after total knee arthroplasty for severe flexion deformity knees, and the rehabilitation method. METHODS: From January 2001 to January 2004, 30 knees (20 cases) with severe flexion deformity were performed total knee arthroplasty with PS prosthesis, and the follow up were at least 6 months (6 to 40 months, average 18 months). All cases in this group were classified with the extensor force grade and were given certain exercises according to the grade. The HSS scores, extensor force, residual flexion deformity, satisfaction scores and rang of motion were recorded pre-operation and 3 days, 2 weeks, 4 weeks, 8 weeks, 12 weeks, 6 months and then every year when follow up. RESULTS: At the end point of the 6 months follow up, all items increased significantly, the average HSS score was 75.9 degrees, the average extensor force was 4.1, 8 knees among the group remained an average flexion deformity with 7.4 degrees, all patients were satisfied with the operation, and the average range of motion was 87.7 degrees. CONCLUSIONS: Quadriceps atrophy for disuse and the relative extensor mechanism excess are the main cause of extensor deficit, correct strength evaluation and individual exercise project are critical principle for successful rehabilitation.