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| 1 | Differences between physiological and pathological convulsive thresholds in patients with epilepsy显示文摘BACKGROUND: Physiological convulsive thresholds degrade when the brain is in some pathologic states; thus, a level of stimulus that cannot provoke a convulsion may evoke a seizure or epileptic seizure. OBJECTIVE: To investigate the changes that occur in the brain when the physiological convulsive threshold becomes pathological, and to determine what differences occur in pathological and physiological convulsive thresholds during the development of epilepsy. DESIGN: A randomized controlled animal experiment. SETTING: Research Institute of Epilepsy of Shanxi Medical University; Department of Neurology, The Third Hospital of Shanxi Medical University; Research Institute of Function of Shanxi Medical University. MATERIALS: Thirty-six female Wistar rats were selected for this study. The rats were obtained from the experimental animal center of Shanxi Medical University. All laboratory procedures complied with animal ethical standards. The animals were randomly divided into three groups: a strong current group, a weak current group and a control group, with 12 rats in each group. An automatic determinator of seizure threshold was made at Shanxi Medical University and Taiyuan University of Technology. Two bipolar stainless steel stimulating electrodes and an electrode connector (diameter 1.2 mm) were made at Taiyuan University of Technology. METHODS: This study was performed in the laboratory of Research Institute of the Epilepsy of Shanxi Medical University between December 2005 and August 2006. The threshold of localized seizures was measured by performing direct cortical stimulation in rats under anesthesia. After 1 week of post-operative recovery, electric stimulation was started with three different kinds of stimulation. Seizure activity was induced by a ramp-shaped single train of biphasic pulses (50 Hz, total pulse duration of 2 ms, increasing from 0 to 2 000 μA in 15 seconds). The threshold of localized seizures (TLS) has been defined as the minimum current intensity necessary to provoke convulsion of the forelimbs and/or facial muscles. Up to the TLS, if stimulation continued, the current intensity necessary to provoke the generalized seizures is called the threshold of generalized seizures (TGS). If stimulation is continued for about 2 seconds when the TGS is reached, rats still showed generalized clonic activity after stimulation ceased. When seizures stopped, a short period of immobility can be observed. The current intensity is called the threshold of prolonged seizures (TPS). The rats in the strong current group were stimulated up to the current level required to reach the TPS. In the course of stimulation, first, the TLS was recorded, then the TGS, and finally the TPS. The stimulation interval in one session was 10 minutes, repeated twice daily. The rats in the weak current group were only stimulated up to the current levels required to reach the TGS; first, the TLS was recorded and then the TGS was measured at the same time as the strong current group. Control animals were also equipped with a full electrode set and placed in the same conditions, but no stimulation took place, only electroencephalogram (EEG) recording at the same times as the experimental groups. MAIN OUTCOME MEASURES: ① Stimulation of the two experimental groups lasted for 11 weeks and then observation of their behavior and electroencephalogram recording continued for 4 weeks. The control group was also observed over a total of 15 weeks. ② Observing neuronal damage/loss in the hippocampus with a light microscope using a 250× visual field. RESULTS: All 36 Wistar rats were included in the final analysis. At the beginning of the experiment, the convulsive thresholds were all above 1 100 μA, although there were significant individual variations among rats of the same group. Those thresholds quickly declined during the initial 4 weeks of repetitive electrical stimulation. The convulsive thresholds approached a constant level in the 10th week after commencement of stimulation. There were no significant changes in thresholds when stimulations lasted longer; the convulsive thresholds and the variations in rats of the same group were significantly lower than at the beginning of the trial (P < 0.01). An interictal discharge was also recorded in the 3rd week in the strong current group, and in the 8th week in the weak current group; these discharges were concomitant with neuronal damage and loss in the hippocampus. There was no abnormality observed in the control group. CONCLUSION: These findings indicated that the convulsion threshold in the brain should be divided intotwo stages: a physiological convulsive threshold and a pathological convulsive threshold (epileptic threshold). The epileptic threshold is created by pathologically acquired factors, which give rise to brain damage. The increase in the intensity of these pathologically acquired factors led to aggravation of damage. | Yuxi Liu Leiyu Geng Jiali Xu Mingzheng Wang Ce Zhang Yu Zhang | 2008 | Neural Regeneration Research2008，3，3： | 3 |
| 2 | Fabrication of Ti-Al complex with superior deformation capability by pressure infiltration显示文摘 | Ce LIANG Feng LI Lin GENG Lu-jun HUANG | 2011 | Transactions of Nonferrous Metals Society of China2011，，： | 1 |
| 3 | Decomposition of the ( 2 + 1 ) - dimensional Gardner equation and its quasi - periodic solutions in Nonlinearity 显示文摘 | Geng Xian - guo Cao Ce - wen | 2001 | (14) : 1433 - 14522001，，14： | 1 |
| 4 | Decomposition of the (2 + 1 ) - dimensional Gardner equation and its quasi - periodic solutions 显示文摘 | Geng Xian - guo Can Ce - wen | 2001 | Nonlinearity2001，，14： | 1 |
| 5 | Role of the PGC-1 family in the metabolic adaptation of goldfish to diet and temperature 显示文摘 | LeMoine CM Genge CE Moyes CD | 2008 | J Exp Bio12008，211，9： | 1 |
| 6 | Integration of Biological Synthesis&Chemical Catalysis:Bio-based Plasticizer trans-Aconitates显示文摘Plasticizers are essential to reduce processing difficulties and improve plastic properties.However,petroleumbased phthalate plasticizers,which are mostly used at present,urgently require alternatives due to their con-firmed and serious health risks.In this study,the green mass production of trans-aconitic acid was achieved via synthetic biotechnology and microbial fermentation,which was further expanded to multiple application sce-narios using chemical esterification,resulting in trans-aconitate plasticizers that are biosafe and environmentally friendly and have high plasticizing efficiency and long-term stability.Different plasticizers with various core structures and alkyl chains were studied to determine their properties as polyvinyl chloride(PVC)plasticizers,and tributyl trans-aconitate displayed the best comprehensive performance with up to 1.24 plasticizing effi-ciency.The possible PVC plasticization mechanism with synergistic solvent,support,and shielding effects was discussed and summarized.Tributyl trans-aconitate has significant potential to replace traditional PVC plasti-cizers in general merchandise,food packaging,medicinal materials,and other products,further promoting the development of the high-quality plastic industry with greener technology and safer applications. | Hongbin Hou Xuenian Huang Zhiqiang Du Jian Guo Min Wang Guangqiang Xu Ce Geng Yunpeng Zhang Qinggang Wang Xuefeng Lu | 2023 | Green Carbon2023，1，1： | 0 |
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