BACKGROUND:The stimulation parameters concern directly the antiepileptic effect and safety of vagus nerve stimulation in epileptic patients, and the optimal setting of these parameters is crucial to ensure safe and effective application for antiepileptic treatment.OBJECTIVE: To observe the effect of such parameters as output current,wave width, frequency, on/off time of intermittent stimulation in electric vagus nerve stimulation for antiepileptic therapy.DESIGN: Single-sample experiment.SETTING: Department of Neurobiology, School of Basic Medical Sciences, Capital University of Medical Sciences.MATERIALS: The experiment was carried out at Electrophysiological Laboratory of Department of Neurobiology, School of Basic Medical Sciences, Capital University of Medical Sciences between September 2000and September 2002, using totally 36 healthy adult Wistar rats.METHODS: Epileptic models were established in 36 healthy adult Wistar rats by cervical subcutaneous kainic acid injection, in which various settings of vagus nerve stimulation parameters were applied and their antiepileptic effects observed in terms of changes in the behaviors, electrocardiogram (ECG), electrocorticogram (ECoG), and hippocampal neuronal discharge to identify the optimal parameter setting.rameters.nerve stimulation produced antiepileptic effect mainly within 4 hours of with wave width of 2 ms, current intensity of 3-3.5 mA, frequency of 30-35 Hz, 1-minute on/2-minute off intermittent stimulation produced remarkable antiepileptic effect presented by obviously reduced seizure duration in ECoG and epileptic severity, with lowered frequency of bursting discharge in the epileptic rat CA1 neurons (P ＜ 0.05).CONCLUSION: With normal cardiac electric activity ensured, the minimum stimulation parameters sufficient for effective epilepsy control can be considered as the optimal parameter setting in electric vagus nerve stimulation, which has no adverse effect on the heart.

BACKGROUND: Vagus nerve stimulation (VNS) is a neurophysiological therapy (NPT) of refractory epilepsy, which can control the seizure by stimulating the vagus nerve stem in cervical part.OBJECTIVE: To study the effect of intermittent left-side VNS on seizure of epileptic animals, and provide theoretic basis for the interaction of somatic information and that of internal organs.DESIGN: Observation study.SETTING: Department of Neurobiology, Capital University of Medical Science.MATERIALS: The experiment was performed in the Laboratory of Electrophysiology in Department of Neurobiology, Capital University of Medical Science from March 2000 to September 2002. Thirty-four healthy adult SD rats and 8 rabbits, weighting (220-250) g and (2.2-2.5) kg respectively were selected.METHODS: ①Ten rats were intramuscularly injected with (150 000-160 000) U of penicillin (PCN). VNS effects on epileptiform activities of rats were studied by observing the changes in electrocorticogram (ECoG)and behavior of rats before and after VNS.②(0.24-0.48) mg of PCN was injected into the hippocampus of another 8 rabbits to induce epilepsy, and VNS effects on ECoG of epileptic rats were observed. ③Seizures of 16 rats were induced by Kainic acid, and changes in discharge activity of hippocampal neuron, ECoG and behavior of epileptic rats were observed after VNS. ④Seizures of 8 rabbits were induced by cortical injection of strychnine with microinjector, and VNS effects on ECoG of rabbits with epilepsy induced by acute cortical injury were observed.MAIN OUTCOME MEASURES: ①VNS effects on seizure of rats with epilepsy induced by PCN. ②VNS effects on seizure of rats with epilepsy induced by Kainic acid. ③VNS effects on epileptiform ECoG of rabbits with epilepsy induced by strychnine.RESULTS: A total of 34 rats and 8 rabbits were involved in the analysis of results. VNS could remarkably suppress the seizure of epileptic animals,and epileptiform ECoG, epileptiform discharges of hippocampal neuron and behavior significantly changed with the total effective rate greater than 50%. The total effective rate of VNS before seizure was greater than 80%.In epilepsy group indoeed by intramuscular injection of PCN, ECoG and behavior were markedlly aneliorated respectively for 40% and 50% of rats.In epilepsy group induced by injection of PCN in hippocampus, the ECoG was siguificantly ameliorated in 50% rats. In epileptic rabbit group induced by partial injection of strychnine via cerebral cortex, the epilepti form wave iu ECoG was controlled by VNS in 50 % of animals.CONCLUSION: VNS can effectively suppress seizure of epileptic animals. The antiepileptic effect of VNS is associated with cerebral cortical aud hippcampal neurons. Somatic epileptiform activity could be effectively inhibited by the integration of visceral afferent information in cortical and hippocampal parts.

Objective To compare the 2 methods of the flow cytometry and the microcolumn gel agglutination assay for testing anti-ABO Ig G antibody.Methods The flow cytometry and the microcolumn gel agglutination assay were adopted to detect the an-ti-ABO IgG antibody in the O blood type pregnant women(experimental group)and the A/B blood type pregnant women (control group).The difference in the positive rates between the experimental and control groups and the correlation between these two methods were analysed.The different titers of samples were selected for detection on different days to compare their reproducibili-ty.Results 300 samples from the experimental goup and 300 samples from the control group were collected.The detection results of 2 methods showed that the positive rates of the experimental group was significantly higher than that of the control group with statistical difference(P <0.05).The correlation coefficients(rs )between these two methods were 0.694.The coefficient of variation in the flow cytometry was smaller than that in the microcolumn gel agglutination assay(P <0.05).Conclusion ABO blood type in-compatibility is more common in O type pregnant women.The flow cytometry and the microcolumn gel agglutination assay possess good correlation.The reproducibility of the flow cytometry is better than that of microcolumn gel agglutination assay.