Intrinsic and extrinsic mechanisms regulating neuronal dendrite morphogenesis / 浙江大学学报·医学版

Neurons are the structural and functional unit of the nervous system. Precisely regulated dendrite morphogenesis is the basis of neural circuit assembly. Numerous studies have been conducted to explore the regulatory mechanisms of dendritic morphogenesis. According to their action regions, we divide them into two categories: the intrinsic and extrinsic regulators of neuronal dendritic morphogenesis. Intrinsic factors are cell type-specific transcription factors, actin polymerization or depolymerization regulators and regulators of the secretion or endocytic pathways. These intrinsic factors are produced by neuron itself and play an important role in regulating the development of dendrites. The extrinsic regulators are either secreted proteins or transmembrane domain containing cell adhesion molecules. They often form receptor-ligand pairs to mediate attractive or repulsive dendritic guidance. In this review, we summarize recent findings on the intrinsic and external molecular mechanisms of dendrite morphogenesis from multiple model organisms, including , and mice. These studies will provide a better understanding on how defective dendrite development and maintenance are associated with neurological diseases.

Isokinetic muscle strength test for the muscular force after repair of ruptured Achilles tendon / 中国组织工程研究

BACKGROUND:Restoration of tendon integrity and tenacity, and maintenance of ankle joint flexibility, play a crucial role on the rupture of Achiles tendon. OBJECTIVE: To evaluate the muscular force using isokinetic muscle strength test after the ruptured Achiles tendon is repaired, and to assess the repairing effect. METHODS: Muscle power including peak torque, peak torque/body weight, total work, average peak torque, set total work of flexor and extensor of 17 patients with Achiles tendon rupture were assessed after reconstruction using Biodex system 4 at 60 (°)/s and 120(°)/s. RESULTS AND CONCLUSION:The peak torque, peak torque/body weight, total work, average peak torque, set total work of flexor muscle group at the injured side were significantly decreased compared with uninjured side at 60 (°)/s and 120 (°)/s (P < 0.05). Isokinetic muscle strength test can reflect the muscular force after the ruptured Achiles tendon is repaired, and evaluate the repairing effect.