Does ipsilateral chronic ankle instability alter kinematics of the other joints of the lower extremities: a biomechanical study.

PURPOSE: We evaluated and compared kinematics of bilateral ankle, knee, and hip joints in patients with chronic unilateral ankle instability (CAI) with healthy controls. METHODS: Fifteen individuals diagnosed with CAI and a control group of 16 individuals were matched. Different peaks within the gait cycle (at different intervals) for the dorsiplantar, inversion/eversion, and abduction/adduction axis were compared between injured and uninjured sides of patients with CAI with a control group. RESULTS: Comparison of the uninjured ankle in CAI with the control group showed higher dorsiflexion in one peak of the stance phase (p = 0.003), higher inversion in one peak of the stance phase (p = 0.022), and the swing phase (p = 0.004). The hip joint of the uninjured side showed higher extension in one peak of the stance phase (p < 0.001), and two peaks of the swing phase (p < 0.05). Furthermore, it showed higher adduction in one peak of the foot flat to mid-stance phase (p = 0.001), higher abduction in one peak of the late swing phase (p = 0.047), and the swing phase (p = 0.032). The knee joint of the uninjured side showed higher flexion in all measured peaks of the gait cycle (p < 0.05) (except for one peak in the late swing phase) compared to the control group. CONCLUSION: Chronic ankle instability results in altered biomechanics of the ipsilateral knee as well as the contralateral ankle, knee, and hip joints. The alterations caused by CAI may predispose patients to overuse and/or acute injuries of other joints of lower extremities during routine and sporting activity.

Electrophysiological modeling of the effect of potassium channel blockers on the distribution of stimulation wave in the human gastric wall cells.

The purpose of this study is to model the electrophysiological behavior of excitable membrane and wavefront propagation in the Stomach Wall in physiological and pharmacological states. The propagation of this wave is based on cellular electrophysiological activity and ionic channel properties. In this study, we arranged the stomach wall cells together using the Gap Junctions approach. Slow wave is generated by gastric pacemaker cells. This wave propagates via the interaction of cells with each other throughout the stomach wall. Potassium currents are one of the main factors in regulating the pattern of wavefront propagation. To investigate the effect of limiting the exchange of potassium currents from cell membranes, 10%, 50%, 90%, and complete blockade were applied on both non-inactivating potassium current (IKni) and fast-inactivating potassium current (IKfi). The results show that IKniion channel blockage has a considerable effect on the plateau phase in the propagation of the excitation wave. The maximum value of the action potential in the plateau phase in the excitation wave with complete obstruction from -40.92 mV in the physiological state reached -18.97 mV, which is about 54% higher than the physiological state. Also, compared to the physiological state, complete blockage of the I_Kfi causes a 15% increase in the slow-wave spike phase (from -36.72 mV to -31.36 mV). Using this model, the effect of ions in different phases of slow-wave can be investigated. In addition, by blocking ion channels, functional disorders and smooth muscle contraction can be improved.