Differential mechanisms of synaptic plasticity for susceptibility and resilience to chronic social defeat stress in male mice.

Mood dysregulation refers to the inability of a person to control their negative emotions, and it is linked to various stressful experiences. Dysregulated neural synaptic plasticity and actin-filament dynamics are important regulators of stress response in animal models. However, until now, there is no evidence to differential the mechanisms of synaptic plasticity and actin-filament dynamics in stress susceptibility and stress-resistant. Here we found that depression-like behaviour was observed in the susceptible group following chronic social defeat stress (CSDS) exposure, but not in stress-resistant mice. High-frequency stimulation-induced long-term potentiation (LTP) was impaired in the CSDS-induced depression-susceptible group. Further, the levels of pro-brain derived neurotrophic factor (BDNF), mature BDNF, PSD-95, phosphorylated CaMKII, and phosphorylated Cofilin, an actin-filament dynamics regulator, were reduced in CSDS-induced depression-susceptible mice unlike in stress-resistant mice. These results demonstrate that synaptic plasticity-related molecules, such as BDNF and phosphorylated Cofilin, are important for maintaining synaptic functions and structure in mice that experience more stress.

Unusual types of distal clavicular fractures: Two case reports.

Distal clavicular fractures were classified by Neer in 1963. A type II fracture leads to a high rate of delayed union, or nonunion, with undesirable symptoms. Type II distal clavicular fractures usually exhibit superior displacement of the clavicle. We report two cases of distal clavicular fracture with inferior displacement and posterior displacement. Open reduction and internal fixation was performed in both patients, resulting in excellent functional outcome. As far as we know, this is the first report for these fracture patterns.

Surgical management of uncomplicated midshaft clavicle fractures: a comparison between titanium elastic nails and small reconstruction plates.

BACKGROUND: This study compared titanium elastic nail (TEN) fixation with plate fixation in patients with uncomplicated midshaft clavicle fractures. METHODS: The records of 57 patients with midshaft clavicular fractures that were operated on within 2 weeks after injury at Kaohsiung Veterans General Hospital, Kaohsiung City, Taiwan, were retrospectively analyzed. Each patient received either TENs (n = 25) or fixation with a 3.5-mm reconstruction plate (n = 32) depending on the preference of the operating surgeon. Operative parameters, postoperative pain and function scores, complications, and fracture union time were determined. RESULTS: There was no difference in the fracture pattern distribution between the 2 groups, and all operations were performed without complications. Operation time, wound size, blood loss, length of hospitalization, and subjective time to pain relief were less for the TEN group than for the 3.5-mm reconstruction plate fixation group (P < .001 for all). Patients in the TEN group showed a greater range of shoulder motion and higher Constant scores than those in the plate fixation group up to 18 weeks after surgery (P < .001 for all). Fewer patients in the TEN group, 4 (16%), requested removal of the implant, as compared with 12 (37.5%) in the plate group. CONCLUSION: Fixation of uncomplicated midshaft clavicle fractures with TENs provides adequate fixation and faster relief of pain and return to normal function of the affected shoulder than fixation with 3.5-mm reconstruction plates.