ObjectiveElectric stimulation of the central nervous system has been served as a treatment method for variety of neurological,psychiatric and sensory disorders.Despite considerable success in some applications,current stimulation techniques offer little control over which neuronal targets are activated by stimulation.This study aimed to present a new shape self-adaptive helix electrode for selective activation of optic nerve.MethodsThe geometric model of optic nerve and new helix electrode was elaborated with COMSOL Multiphysics.The new helix electrodes consist of silicone helix frame,which acted as support and insulation,and platinum contacts embedded within the frame.The activating function (AF) was introduced to characterize the stimulation effects,and the selectivity of activating optic nerve fascicle with new helix electrode was simulated by COMSOL Multiphysics,taking into account the variations of electrode contact locations.ResultsAssuming normalized AF threshold was 0.1 V/m2,the ratio difference of AF over threshold between new helix electrode and traditional electrode was only 1.2410％.With contacts in two ends of helix electrode closer to the middle contact,the small nerve fascicle was first activated and then the large one.ConclusionThe results show that the new helix electrodes have the same stimulation effects as that of traditional cuff electrodes.The new helix electrodes can selectively activate optic nerve fascicle with variations of electrode contact locations.

ObjectiveOptic nerve stimulation with penetrating electrode.is a new method for developing visual prosthesis.A simulation system was developed with computer software MATLAB to investigate its mechanism.MethodsVolume conductor model of optic nerve and optic nerve fiber model were developed.With the stimulation of monopolar penetrating electrode,the excitation thresholds of fibers at different depth were calculated.The activating function and activation region were employed to characterize the external stimulation effect.The impact of different parameters on stimulation effects were explored by changing the fiber diameter and the stimulation pulse width.Results Excitation thresholds increased as well as the percentage of activated fibers with the increase of electrode-fiber distance.Excitation threshold of the same depth fiber decreased as the fiber diameter increased,and the longer the electrode-fiber distance was,the more significant the drop was.Excitation threshold of the same depth fiber decreased as the pulse width of monophasic rectangle wave increased.The excitation threshold of the fiber at the same depth hardly changed for pulse durations greater than 0.5 ms.ConclusionThe simulation results indicates that optical nerve stimulation can be realized with penetratingelectrode,and different stimulation parameters can produce different activation effects.The present results providetheoretical guidance for the design of experiments.

nts were tend to suffer from AKI, with the most common cause of pre-renal injury and drugs such as antibiotics and contrast medium used in X-ray imaging. Outcomes of the patients with AKI depends on severity of their kidney injury.

ObjectiveIn this paper a new application of LABVIEW in neural electrophysiological simulation was applied to simulate axonal excitability.MethodsA variety of axonal excitability of the squid giant axon was modeled with LABVIEW,including action potential threshold,refractoriness,temporal summation,anode break excitation,repetitive firing and conduction velocity.ResultsThe LABVIEW program accurately described the permeability changes of Na+ and K+ and their effects on the action potential,and the membrane excitability had been well predicted.ConclusionThe graphical programming language of LABVIEW allows the user to complete the programming by dragging and dropping icons and connecting wires,the users can quickly and easily construct their own biological research systems.

Objective To study the gene expressions of nestin and stem cell factor(SCF)in neurons after ischemia-reperfusion injury in rat brain. Methods Thirty-six adult female rats were subject to left middle cerebral artery occlusion for 1.5h and different hours of reperfusion. In site hybridization was used to examine the expression of nestin and SCF mRNA in the rats subjected to 2h, 6h, 12h, 24h, 2d, 3d, 7d, 14d of reperfusion and sham-operation group (n=4). Results (1) Nestin expression in cortex, striatum and extraventricular zone was weak in the sham-operation group, and increased markedly in the ischemic hemisphere compared with sham-operation group except of reperfusion 2h in cortex, 2h, 6h in striatum, 2h, 6h and 14d in extraventricular zone. (2)SCF expression in cortex, striatum and extraventricular zone was weak in the sham-operation group, and increased markedly in the ischemic hemisphere compared with sham-operation group except of reperfusion 2h, 6h, 12h in cortex, 2h, 6h in striatum, 2h and 14d in extraventricular zone. Conclusion It is suggested that SCF expression might enhance the proliferation of neural stem cells following ischemia-reperfusion in rats.

In order to study the underlying electrode-nerve functional mechanism, optimize the electrode design and guide the prosthesis application, we applied finite element method to analyze the spatial distribution of electric field generated by optic nerve electrical stimulation with spiral cuff electrode. A macroscopic cylindrical model of optic nerve was elaborated, taking into account of electrode contact configurations and possible variations of the thickness of cerebrospinal fluid (CSF). By building an appropriate mesh on this model and under some boundary conditions, the finite element method was applied to compute the 3D electric field generated by the electrode with finite element software COMSOL Multiphysics. The stimulation results indicated that, under the same conditions of stimulation, the longitudinal tripolar electrode structure could generate larger current density than that of biopolar electrode structure (located in the opposite of nerve trunk). However biopolar electrode structure requirs less leads, and is more easily implanted. By means of parametric sweep, the results suggest that, with the increase of the CSF thickness and a higher conductivity of CSF than those of other tissues, the distribution of electric field generated by electrodes is extended but scattered, and the diffuse current distribution makes nerve stimulation less effective.
Electric Stimulation ; Electrodes, Implanted ; Electromagnetic Fields ; Extracellular Space ; Finite Element Analysis ; Humans ; Optic Nerve ; cytology ; physiopathology ; Visual Prosthesis

Objective To observe the effects of expressions of neurocyte adhesion molecule (NCAM) and growth associated protein-43 (GAP-43) in neurological function recovery following cerebral ischemia-reperfusion in rats. Methods The model of focal ischemia-reperfusion in SD rat was induced by intraluminal middle cerebral artery (MCA) occlusion with a nylon monofilament suture. In situ hybridization (ISH) was performed to examine the expression of NCAM mRNA and GAP-43 mRNA at 2,12 h and 1,2,3,7,14 d after reperfusion and in sham-operated controls. Results There was no functional deficit and little expression of NCAM mRNA and GAP-43 mRNA in brain cells in rats of the sham-operated group. In the experimental group, NCAM mRNA expression was observed after reperfusion for 2 h in cortex and striatum and peaked at 12 h and was still higher at 7 d. The neurological function improved at reperfusion of 3 d~14 d compared to reperfusion 2 h. In the ischemic cortex and striatum, GAP-43 mRNA expression demonstrated "double-peak" at 12 h and 2 d after reperfusion, then decreased gradually to the level of sham-operated group at 14 d. Conclusion The increasing NCAM expression might be an important factor of the neural reparation and GAP-43 might enhance the neurological functional recovery with ischemic brain injury in rat.

This study was aimed to search anti-platelet aggregation effectors from Gardenia jasminoides extract with the employment of platelet affinity extraction method coupled with HPLC, in order to provide pharmacological experi-mental evidences of the selected effectors to verify its feasibility. Under physiological conditions, washed rat platelets were added into G. jasminoides extract and then a mixture was gained. Consequently, some components from G. jas-minoides extract were combined to the platelets in the mixture while some were not owing to their special chemical structures and properties. Firstly, the uncombined components were washed off from the mixture. Secondly, the com-bined components in the leftover was washed down and collected, respectively, right after destroying the occupied platelets' structures. Thirdly, different collected eluents were analyzed, respectively, by HPLC established in the pre-vious work to search the effectors. Fourthly, pharmacological experiments were implemented for confirmation. The re-sults showed that dominant effective components from G. jasminoides extract acting on anti-platelet aggregation were identified as geniposide. Further evident was provided as well by pharmacological experiment that geniposide exhibit-ed significant inhibitory effect on anti-platelet aggregation in rats induced by ADP, rat tail collagen and thrombin(P< 0.01). It was concluded that the platelet affinity extraction-HPLC method proposed in this paper can be utilized to analyze the correlation of effectors from G. jasminoides extract and its pharmacological effects. Moreover, there are some correlations between screened chemical substances and their pharmacological effects.

Objective: To assess the feasibility of HEAD-US scale in the clinical application of hemophilic arthropathy (HA) and propose an optimized ultrasound scoring system. Methods: From July 2015 to August 2017, 1 035 joints ultrasonographic examinations were performed in 91 patients. Melchiorre, HEAD-US (Hemophilic Early Arthropathy Detection with UltraSound) and HEAD-US-C (HEAD-US in China) scale scores were used respectively to analyze the results. The correlations between three ultrasound scales and Hemophilia Joint Health Scores (HJHS) were evaluated. The sensitivity differences of the above Ultrasonic scoring systems in evaluation of HA were compared. Results: All the 91 patients were male, with median age of 16 (4-55) years old, including 86 cases of hemophilia A and 5 cases hemophilia B. The median (P₂₅, P₇₅) of Melchiorre, HEAD-US and HEAD-US-C scores of 1 035 joints were 2(0,6), 1(0,5) and 2(0,6), respectively, and the correlation coefficients compared with HJHS was 0.747, 0.762 and 0.765 respectively, with statistical significance (P<0.001). The positive rates of Melchiorre, HEAD-US-C and HEAD-US scale score were 63.0% (95%CI 59.7%-65.9%), 59.5% (95%CI 56.5%-62.4%) and 56.6% (95%CI 53.6%-59.6%) respectively, and the difference was statistically significant (P<0.001). Even for 336 cases of asymptomatic joints, the positive rates of Melchiorre, HEAD-US-C and HEAD-US scale score were 25.0% (95%CI 20.6%-29.6%), 17.0% (95%CI 12.6%-21.1%) and 11.9% (95%CI 8.4%-15.7%) respectively, and the difference was statistically significant (P<0.001). There were significant changes (P<0.05) in the ultrasonographic score of HA before and after onset of hemorrhage in 107 joints of 40 patients. The difference in variation amplitude of HEAD-US-C scores and HEAD-US scores before and after joint bleeding was statistically significant (P<0.001). Conclusion Compared with Melchiorre, there were similar good correlations between HEAD-US, HEAD-US-C and HJHS. HEAD-US ultrasound scoring system is quick, convenient and simple to use. The optimized HEAD-US-C scale score is more sensitive than HEAD-US, especially for patients with HA who have subclinical state, which make up for insufficiency of sensitivity in HEAD-US scoring system

Objective: To explore the evaluation of joint injury by HEAD-US-C (Hemophilic Early Arthropathy Detection with UltraSound in China, HEAD-US-C) in patients with moderate or severe hemophilia A treated with prophylaxis vs on-demand. Methods: The patients from June 2015 to July 2017 with moderate or severe hemophilia A were examined by ultrasound imaging of the elbows, knees and ankles; Meanwhile the HEAD-US-C ultrasound assessment scale and hemophilia joint health score scale 2.1 (HJHS2.1) were used to score the joint status. The correlation between the HEAD-US-C and HJHS score was performed in prophylaxis group and on-demand group patients, respectively. Results: A total of 925 cases of joint ultrasonography were conducted in 70 patients with moderate or severe hemophilia A. Among patients with moderate hemophilia, the median (IQR) of HEAD-US-C score and HJHS score in on-demand group were significantly higher than those in the prophylaxis group[1 (0, 6) vs 0.5 (0, 3) , z=0.177, P=0.046],[2 (0, 4) vs 2 (0, 3) z=0.375, P=0.007], even though there was no significant difference of the median (IQR) number of annualized target joints bleeding episodes between on-demand and prophylaxis groups[1 (0, 7) vs 1 (0, 5) , z=1.271, P=0.137]. Unlike in moderate cases, on-demand treatment group had more annualized target joints bleeding episodes than prophylaxis group among patients with severe hemophilia[3 (0, 8) vs 2 (0, 8) , z=0.780 P=0.037]. The prophylaxis group compared favorably with on-demand therapy group in terms of HEAD-US-C score[1 (0, 6) vs 4 (0, 7) , z=2.189, P=0.008], and HJHS score[2 (0, 5) , 4 (1, 6) , z=3646, P<0.001]for the severe hemophilia patients. The positive correlation between HEAD-US-C score and HJHS score was identified (P<0.05) , whether on-demand treatment or prophylaxis groups. The correlation coefficient between HEAD-US-C score and HJHS score in on-demand treatment and prophylaxis groups were 0.739 (95% CI 0.708-0.708) , 0.865 (95% CI 0.848-0.848) respectively, and 95% CI didn’t overlap (P<0.05) , indicating that the correlation coefficient in prophylaxis group had stronger correlation than that in on-demand group. Conclusions Clinical effects of prophylaxis were significantly better than those of on-demand treatment in patients with moderate or se-vere haemophilia A. HEAD-US-C scoring system could effectively evaluate joints damage in hemophilia A patients treated with on-demand or prophylaxis, companied by significantly positive correlation with HJHS clinical evaluation system, and provided objective index for clinical effect assessment.