Objective To analyze the activity of the vastus medialis (VM) and vastus lateralis (VL) muscles in the dynamic stabilization of the patella in patients with patellofemoral pain (PFPS) using standard surface electromyographic (sEMG) tests.Methods This comparative study involved 7 patients with PFPS (13 knees) and 10 healthy subjects (20 knees).They performed weight-bearing squat movements,and sEMG was employed to measure the mean amplitude and the time before peak (TBP) of their VM and VL muscles.Results There was no significant difference between the two groups in the ratio of the mean amplitudes of the VM and VL muscles.However,the ratio in both groups in squatting was significantly higher than when simply standing.In the PFPS group the average TBP delay of the VM relative to the TBP of the VL was significantly longer than in the control group during squat movements.Conclusions The delay in the TBP of the VM relative to the VL during squat movements could serve as a standardized test for assessing treatment effect in patients with local factor PFPS.

Objective To investigate the effects of inhibition of adenosine monophosphate -activated protein kinase (AMPK) on expressions of cytochrome c (CytC) and caspase -3 and apoptosis in the cerebral cortex after cerebral ischemia-reperfusion injury in mice. Methods Thirty-six male C57BL/6 mice w ere randomly divided into three groups, a sham operation group, a ischemia -reperfusion group, and a AMPK inhibitor group, 12 in each group. A model of middle cerebral artery occlusion w as induced by suture method. The AMPK inhibitor compound C ( 20 mg/kg) w as injected intraperitonealy in the AMPK inhibitor group, the equal volume normal saline w as injected intraperitonealy in the sham operation group and the ischemia-reperfusion group w hen a thread w as inserted. Immunohistochemical staining w as used to detect the expression levels of CytC and caspase-3 and TUNEL method w as used to detect apoptosis at 24 h after ischemia-reperfusion. Results Compared w ith the ischemia-reperfusion group, the numbers of CytC (28.86 ±9.65/HP vs.58.86 ±9.65/HP; t = 7.615, P = 0.030 ) and caspase-3 (7.16 ±5.85/HP vs. 14.36 ±7.85/HP; t =2.548, P =0.035), and TUNEL (67.14 ±8.55/HP vs.95.00 ±13.51/HP; t = 6.891, P = 0.030) positive cels in the cerebral cortex w ere reduced significantly in the AMPK inhibitor group. Conclusion Inhibition of AMPK activity after cerebral ischemia-reperfusion may decrease apoptosis by dow nregulating the expressions of CytC and caspase -3, and play a neuroprotective effect.