A Wirelessly Powered 4-Channel Neurostimulator for Reconstructing Walking Trajectory.

A wirelessly powered four-channel neurostimulator was developed for applying selective Functional Electrical Stimulation (FES) to four peripheral nerves to control the ankle and knee joints of a rat. The power of the neurostimulator was wirelessly supplied from a transmitter device, and the four nerves were connected to the receiver device, which controlled the ankle and knee joints in the rat. The receiver device had functions to detect the frequency of the transmitter signal from the transmitter coil. The stimulation site of the nerves was selected according to the frequency of the transmitter signal. The rat toe position was controlled by changing the angles of the ankle and knee joints. The joint angles were controlled by the stimulation current applied to each nerve independently. The stimulation currents were adjusted by the Proportional Integral Differential (PID) and feed-forward control method through a visual feedback control system, and the walking trajectory of a rat's hind leg was reconstructed. This study contributes to controlling the multiple joints of a leg and reconstructing functional motions such as walking using the robotic control technology.

Transplantation of embryonic motor neurons into peripheral nerve combined with functional electrical stimulation restores functional muscle activity in the rat sciatic nerve transection model.

Reinnervation of denervated muscle by motor neurons transplanted into the peripheral nerve may provide the potential to excite muscles artificially with functional electrical stimulation (FES). Here we investigated whether transplantation of embryonic motor neurons into peripheral nerve combined with FES restored functional muscle activity in adult Fischer 344 rats after transection of the sciatic nerve. One week after sciatic nerve transection, cell culture medium containing (cell transplantation group, n = 6) or lacking (surgical control group, n = 6) dissociated embryonic spinal neurons was injected into the distal stump of the tibial and peroneal nerves. Electrophysiological and tissue analyses were performed in the cell transplantation and surgical control groups 12 weeks after transplantation, as well as a in naïve control group (n = 6) that received no surgery. In the cell transplantation group, ankle angle was measured during gait, with and without FES of the peroneal nerve. Ankle angle at mid-swing was more flexed during gait with FES (26.6 ± 8.7°) than gait without FES (51.4 ± 12.8°, p = 0.011), indicating that transplantated motor neurons in conjunction with FES restored ankle flexion in gait, even though no neural connection between central nervous system and muscle was present. These results indicate that transplantation of embryonic motor neurons into peripheral nerve combined with FES can provide a novel treatment strategy for paralysed muscles. Copyright © 2013 John Wiley & Sons, Ltd.

Docosahexaenoic acid is an independent predictor of all-cause mortality in hemodialysis patients.

BACKGROUND: Dietary n-3 polyunsaturated fatty acids (PUFAs), docosahexaenoic acid (DHA) and eicosapentaenoic acid have been shown to reduce cardiovascular mortality. Patients on hemodialysis (HD) have a very high mortality from cardiovascular disease. Fish consumption reduces all-cause mortality in patients on HD. Moreover, n-3 PUFAs, especially DHA levels in red blood cells (RBCs), are associated with arteriosclerosis in patients on HD. The aim of this study was to determine whether DHA levels in RBCs predict the mortality of patients on HD in a prospective cohort study. METHODS: A cohort of 176 patients (64.1 ± 12.0 (mean ± SD) years of age, 96 men and 80 women) under HD treatment was studied. The fatty acid composition of their RBCs was analyzed by gas chromatography. RESULTS: During the study period of 5 years, 54 deaths occurred. After adjustment for 10 confounding factors, the Cox hazard ratio of all-cause mortality of the patients on HD in the highest DHA tertile (>8.1%, 15 deaths) was 0.43 (95% CI 0.21-0.88) compared with those patients in the lowest DHA tertile (<7.2%, 21 deaths). CONCLUSION: The findings suggest that the level of DHA in RBCs could be an independent predictor of all-cause mortality in patients on HD.

Ceramic acetabular liner fracture in total hip arthroplasty with a ceramic sandwich cup.

In total hip arthroplasty, a modular acetabular component with a sandwich insertion (alumina ceramics/polyethylene/titanium) was proposed. The polyethylene layer might reduce the rigidity of the ceramics and prevent an impingement between the ceramic liner rim and the femoral neck. A case of an acetabular liner fracture of the ceramic sandwich cup was presented. The fracture occurred 1.4 years after the operation without trauma. Because the ceramic liner rim was hit by the head following the impingement between the neck and the polyethylene, the cause of the fracture might be the stress concentration at the rim of the ceramic liner, of which the thickness was only 4 mm. At revision surgery, the fractured ceramic liner was replaced with a polyethylene liner without inner ceramic liner.