Electric field stimulation (EFS) can effectively inhibit local Ca2+ influx and secondary injury after spinal cord injury (SCI). However, after the EFS, the Ca2+ in the injured spinal cord restarts and subsequent biochemical reactions are stimulated, which affect the long-term effect of EFS. Polyethylene glycol (PEG) is a hydrophilic polymer material that can promote cell membrane fusion and repair damaged cell membranes. This article aims to study the combined effects of EFS and PEG on the treatment of SCI. Sprague-Dawley (SD) rats were subjected to SCI and then divided into control group (no treatment, n = 10), EFS group (EFS for 30 min, n = 10), PEG group (covered with 50% PEG gelatin sponge for 5 min, n = 10) and combination group (combined treatment of EFS and PEG, n = 10). The measurement of motor evoked potential (MEP), the motor behavior score and spinal cord section fast blue staining were performed at different times after SCI. Eight weeks after the operation, the results showed that the latency difference of MEP, the amplitude difference of MEP and the ratio of cavity area of spinal cords in the combination group were significantly lower than those of the control group, EFS group and PEG group. The motor function score and the ratio of residual nerve tissue area in the spinal cords of the combination group were significantly higher than those in the control group, EFS group and PEG group. The results suggest that the combined treatment can reduce the pathological damage and promote the recovery of motor function in rats after SCI, and the therapeutic effects are significantly better than those of EFS and PEG alone.
Transcranial magnetic stimulation (TMS), a widely used neuroregulatory technique, has been proven to be effective in treating neurological and psychiatric disorders. The therapeutic effect is closely related to the intracranial electric field caused by TMS, thus accurate measurement of the intracranial electric field generated by TMS is of great significance. However, direct intracranial measurement in human brain faces various technical, safety, ethical and other limitations. Therefore, we have constructed a brain phantom that can simulate the electrical conductivity and anatomical structure of the real brain, in order to replace the clinical trial to achieve intracranial electric field measurement. We selected and prepared suitable conductive materials based on the electrical conductivity of various layers of the real brain tissue, and performed image segmentation, three-dimensional reconstruction and three-dimensional printing processes on each layer of tissue based on magnetic resonance images. The production of each layer of tissue in the brain phantom was completed, and each layer of tissue was combined to form a complete brain phantom. The induced electric field generated by the TMS coil applied to the brain phantom was measured to further verify the conductivity of the brain phantom. Our study provides an effective experimental tool for studying the distribution of intracranial electric fields caused by TMS.
Tumor-treating fields (TTFields) is a novel treatment modality for malignant solid tumors, often employing electric field simulations to analyze the distribution of electric fields on the tumor under different parameters of TTFields. Due to the present difficulties and high costs associated with reproducing or implementing the simulation model construction techniques, this study used readily available open-source software tools to construct a highly accurate, easily implementable finite element simulation model for TTFields. The accuracy of the model is at a level of 1 mm3. Using this simulation model, the study carried out analyses of different factors, such as tissue electrical parameters and electrode configurations. The results show that factors influncing the distribution of the internal electric field of the tumor include changes in scalp and skull conductivity (with a maximum variation of 21.0% in the treatment field of the tumor), changes in tumor conductivity (with a maximum variation of 157.8% in the treatment field of the tumor), and different electrode positions and combinations (with a maximum variation of 74.2% in the treatment field of the tumor). In summary, the results of this study validate the feasibility and effectiveness of the proposed modeling method, which can provide an important reference for future simulation analyses of TTFields and clinical applications.
Objective To systematically evaluate the effectiveness and safety of pulsed field ablation (PFA) and radiofrequency ablation (RFA) in the treatment of atrial fibrillation. Methods Computer searches were conducted on PubMed, EMbase, The Cochrane Library, The Web of Science, China Biomedical Literature Database, CNKI, Wanfang, and VIP databases, with a search period from the establishment of each database until April 2025. Two researchers conducted literature screening, data extraction, and quality evaluation of the included studies based on predetermined inclusion and exclusion criteria. Standardized electronic forms were used for data extraction, with a focus on the balanced dataset after propensity score matching (PSM). Quality evaluation was conducted using the improved Newcastle Ottawa scale (NOS). Meta analysis was conducted using RevMan 5.4 and Stata 18.0 software, and subgroup analysis was performed based on the study type (whether PSM method was used or not). ResultsFinally, 14 studies were ultimately included, of which 6 studies applied the PSM method, with a total sample size of 3 172 cases (PFA group: 1 582 cases; RFA group: 1 590 cases. NOS score≥5 points. The meta-analysis results showed that the PFA group had a lower recurrence rate of atrial fibrillation [OR=0.75, 95%CI (0.63, 0.90), P=0.002], surgical complications [OR=0.63, 95%CI (0.41, 0.98), P=0.04], and surgical time [WMD=–37.32, 95%CI (–45.85, –28.78), P<0.001] compared to the RFA group, and the differences were statistically significant. In addition, compared to the PFA group, the RFA group had a shorter X-ray exposure time [WMD=7.65, 95%CI (4.41, 10.88), P<0.001], and the difference was statistically significant. There was no statistically significant difference between the two groups in terms of re ablation rate [OR=1.17, 95%CI (0.59, 2.31), P=0.65] and acute surgical success rate [OR=0.86, 95%CI (0.22, 3.35), P=0.82]. ConclusionCompared with RFA, PFA treatment for atrial fibrillation can reduce the recurrence rate, shorten the surgical time, and reduce surgical complications, indicating its good effectiveness and safety in the treatment of atrial fibrillation.
Action of electromagnetic radiation exerting on human body has been a concerned issue for people. Because electromagnetic waves could generate an electric stress in a discontinuous medium, we used the finite difference time domain (FDTD) as calculation methods to calculate the electric stress and its distribution in human head caused by high-frequency low-power electromagnetic environment, which was generated by dual-band (900 MHz and 1 800 MHz) PIFA antennas with radiated power 1 W, and we then performed the safety evaluation of cell phone radiation from the angle whether the electric stress further reached the human hearing threshold. The result showed that there existed the electric stress at the interface of different permittivity organization caused by the two kinds of high-frequency low-power electromagnetic environment and the maximum electric stress was located at the interface between skin and air of the phone side, and the electric stress peak at skull did not reach the threshold of auditory caused by bone tissue conduction so that it can not produce auditory effects.
Abstract： Objective To investigate the influence of vasoactive intestinal peptide （VIP) on the sling fibers and the clasp fibers of the lower esophageal sphincter （LES） and the difference， and explore whether VIP belongs to a nonadrenergic and noncholinergic （NANC） neurotransmitter. Methods Thirty LES specimens were obtained from 30 patients with high-position carcinoma of the middle thoracic esophagus who underwent esophagectomy from March to August 2010 in Fourth Affiliated Hospital of Hebei Medical University. There were 14 male patients and 16 female patients with their average age of 58.0±6.1 years. The clasp fibers and sling fibers were isolated and suspended in perfusion. Exogenous VIP was added to the two kinds of strips to draw a concentration-effect curve. Electric field stimulation （EFS） or exogenous VIP was applied to clasp fibers and sling fibers， and the influence of VIP （10-28） on LES was compared. Results ExogenousVIP in different concentration caused concentration-dependent relaxation of the sling fibers and clasp fibers of LES in vitro. There was statistical difference in relaxation between the sling fibers and clasp fibers under same VIP concentration （P＜0.05）， and the relaxation of sling fibers was more significant than that of clasp fibers. VIP （10-28） transiently inhibited the relaxationof the sling fibers and clasp fibers caused by exogenous VIP. VIP （10-28） also transiently inhibited the relaxation of the sling fibers and clasp fibers after the activation of EFS. Conclusion The relaxation of sling fibers and clasp fibers induced by EFS is related to VIP. VIP is a kind of NANC neurotransmitter in human LES.
In transcranial magnetic stimulation (TMS), the conductivity of brain tissue is obtained by using diffusion tensor imaging (DTI) data processing. However, the specific impact of different processing methods on the induced electric field in the tissue has not been thoroughly studied. In this paper, we first used magnetic resonance image (MRI) data to create a three-dimensional head model, and then estimated the conductivity of gray matter (GM) and white matter (WM) using four conductivity models, namely scalar (SC), direct mapping (DM), volume normalization (VN) and average conductivity (MC), respectively. Isotropic empirical conductivity values were used for the conductivity of other tissues such as the scalp, skull, and cerebrospinal fluid (CSF), and then the TMS simulations were performed when the coil was parallel and perpendicular to the gyrus of the target. When the coil was perpendicular to the gyrus where the target was located, it was easy to get the maximum electric field in the head model. The maximum electric field in the DM model was 45.66% higher than that in the SC model. The results showed that the conductivity component along the electric field direction of which conductivity model was smaller in TMS, the induced electric field in the corresponding domain corresponding to the conductivity model was larger. This study has guiding significance for TMS precise stimulation.
ObjectiveTo investigate the effect of different electrical stimulation waves on orientation and alignment of adipose derived mesenchymal stem cells (ADSCs).MethodsADSCs were isolated from 5-week-old Sprague Dawley rats (weight, 100-150 g) and cultivated. The cells at passages 3-5 were inoculated to prepare cell climbing slices, subsequently was exposed to direct-current electrical stimulations (ES) at electric field strengths of 1, 2, 3, 4, 5, and 6 V/cm on a homemade electric field bioreactor (groups A1, A2, A3, A4, A5, and A6); at electric field strength of 6 V/cm, at 50% duty cycle, and at frequency of 1 and 2 Hz (groups B1 and B2) of square wave ES; at electric field strength of 6 V/cm, at pulse width of 2 ms, and at frequency of 1 and 2 Hz (groups C1 and C2) of biphasic pulse wave ES; and no ES was given as a control (group D). The changes of cellular morphology affected by applied ES were evaluated by time-lapse micropho-tography via inverted microscope. The cell alignment was evaluated via average orientation factor (OF). The cytoske-leton of electric field treated ADSCs was characterized by rhodamine-phalloidin staining. The cell survival rates were assessed via cell live/dead staining and intracellular calcium activities were detected by calcium ion fluorescent staining.ResultsThe response of ADSCs to ES was related to the direct-current electric field intensity. The higher the direct-current electric field intensity was, the more cells aligned perpendicular to the direction of electric field. At each time point, there was no obvious cell alignment in groups B1, B2 and C1, C2. The average OF of groups A5 and A6 were significantly higher than that of group D (P<0.05), but no significant difference was found between other groups and group D (P>0.05). The cytoskeleton staining showed that the cells of groups A5 and A6 exhibited a compact fascicular structure of cytoskeleton, and tended to be perpendicular to the direction of the electric field vector. The cellular survival rate of groups A4, A5, and A6 were significantly lower than that of group D (P<0.05), but no significant difference was found between other groups and group D (P>0.05). Calcium fluorescence staining showed that the fluorescence intensity of calcium ions in groups A4, A5, and A6 was slightly higher than that in group D, and no significant difference was found between other groups and group D.ConclusionThe direct-current electric field stimulations with physiological electric field strength (5 V/cm and 6 V/cm) can induce the alignment of ADSCs, but no cell alignment is found under conditions of less than 5 V/cm direct-current electric field, square wave, and biphasic pulse wave stimulation. The cellular viability is negatively correlated with the electric field intensity.
Tumor treating fields (TTF) therapy is an innovative tumor treatment modality. Currently, the TTF devices predominantly employ insulated ceramic electrodes as the electric field transmission medium, resulting in low energy transfer efficiency of the electric field and poor portability of the devices. This study proposed an innovative TTF transmission mode and independently designed a conducted-electrode TTF cell culture dish utilizing inert titanium materials. The electric field conduction characteristics were verified through finite element simulations and experimental tests. Finally, based on the self-manufactured conducted-electrode TTF cell culture dish, experiments on the proliferation inhibition of U87 tumor cells by TTF were conducted. The results demonstrated that under an applied TTF voltage of 10 V and frequency of 200 kHz, the electric field intensities within the medium for conducted and insulated electrodes are approximately 2.5 V/cm and 0.7 V/cm, respectively. Compared to conventional insulated TTF systems, the conducted-electrode TTF configuration exhibited a lower electrode voltage drop and a higher electric field intensity in the culture medium, indicating superior electric field transmission efficiency. Following 36 hours of treatment with conducted-electrode TTF on U87 cells, the proliferation inhibition rate reached approximately 50%, demonstrating effective suppression of tumor cell growth. This approach presents a potential direction for optimizing TTF treatment modality and device design.
Thirty adult healthy rabbits were divided into 3 groups at random. Under the identical experimental conditions, the trunk of right facial nerve of each nerve. Two weeks late, the caudal end of the divided facial nerve was anastomized with the cephlad end of the divided main trunk of the nerve to the masseter muscle. The anode-cathode and cathode-anode silver electrodes site. The electric field intensity between the two silve electrode plates was maintained at 37.5 millivolts per millimeter. Those without the placement of the electrode were the control group. From the results of the experiment, it was noted that the rate of growth of the nerve in the cathodal group was highly significant.