Acute hemodynamic responses to electroconvulsive therapy are not related to the duration of seizure activity

Study Objective: To test the hypothesis that the magnitude of the acute hemodynamic response to electroconvulsive therapy (ECT) is related to the duration of the seizure activity in patients receiving different dosages of intravenous (IV) lidocaine.

Design: Randomized, double-blind, placebo-controlled, cross-over study.

Setting: University-affiliated hospital.

Patients: 21 ASA physical status I, II, and III patients undergoing four consecutive maintenance ECT treatments for chronic depression.

Interventions: Patients received lidocaine 50 mg, 100 mg, 200 mg IV, or saline prior to induction of anesthesia via a standardized anesthetic technique.

Measurements and Main Results: Noninvasive blood pressure (BP) and heart rate (HR), as well as the duration of motor and electroencephalographic (EEG) seizure, were measured. The duration of motor and EEG seizures (means ± SD) were 37 ± 13 sec and 64 ± 21 sec, 25 ± 11 sec and 52 ± 43 sec, 17 ± 12 sec and 32 ± 17 sec, 1 ± 3 sec and 18 ± 10 sec in the saline, lidocaine 50 mg, 100 mg, 200 mg groups, respectively. Although the duration of seizure activity was decreased in a dose-related fashion after lidocaine pretreatment, the peak increases in BP and HR were similar in the lidocaine and saline treatment groups.

Conclusions: Despite producing dose-related decreases in the duration of both motor and EEG seizure activity, lidocaine failed to attenuate the acute hemodynamic response to ECT. Thus, the acute hemodynamic response to ECT is not related to the duration of seizure activity.     

Michaelis—Menten兼有一级消除动力学模型平均稳态时的一些特性

本文将Rowland等人的二房室模型中的消除过程扩展成米氏兼一级消除过程。据此,推导出达到稳态浓度的时间、血药浓度-时间曲线下面积和生物利用度的公式;进而得到平均清除率和剂量间的关系以及剂量与平均清除率和血浆浓度呈线性关系的结论。     

Mono- or Polypharmacotherapy in Institutionalized Epileptic Children with Severe Mental Retardation?

ABSTRACT. Nine severely mentally retarded patients with severe epilepsy who were living in an institution were studied during a three-year period by a multi-disciplinary team. A seizure rate serum level chart was made for each patient. It served as the basis for monthly discussions in the team about medication changes. Drug plasma concentrations were monitored monthly. Statistical comparisons between seizure frequency on different drug regimens were made by χ² test. Withdrawal of all medication was possible in one case and reduction to monotherapy in two cases. In the remainder of the patients a combination of two or three anticonvulsants gave the best clinical effect. We thus found polypharmacotherapy necessary for some severely retarded patients with epilepsy. Our multidisciplinary approach and chart monitoring system has many advantages and is valuable for the medical care and drug treatment of this patient category.     

Frontal versus transcorneal stimulation to induce maximal electroshock seizures or kindling in mice and rats

Frontal stimulation, i.e. electrical stimulation where electrodes are pressed on the skin of the intact frontal skull of mice or rats, may represent a more humane alternative to the widely used transcorneal stimulation to induce electroshock seizures. The aim of this work was to directly compare transcorneal and frontal stimulation in eliciting maximal electroshock-induced seizures (MES) in mice and the anticonvulsant effect of carbamazepine (CBZ) and phenytoin (PHT) on thus produced seizures. In addition, we stimulated mice and rats repeatedly via transcorneal and frontal electrodes to see whether kindling is produced by this procedure. Two electroshock tests were used in mice, i.e. maximal electroshock seizure threshold (MEST) test and MES generated by supramaximal stimulation (50 mA). Frontal stimulation resulted in lower convulsive threshold than in the case of corneal stimulation. Both CBZ and PHT produced dose-dependent increases in seizure threshold for both sites of stimulation, i.e. transcorneal and frontal. As regards type of electrodes, higher doses of PHT were required to increase seizure threshold in the case of frontal than transcorneal stimulation. Supramaximal stimulation (50 mA) yielded comparable ED₅₀ values regardless of the site of stimulation. Furthermore, once-daily stimulation of mice, regardless of the placement of electrodes, did not induce any changes in convulsive threshold. We also attempted to kindle mice and rats via corneal and frontal electrodes by repetitive electrical stimulation using currents which initially did not produce generalized clonic seizures. Mice were stimulated once daily for 2 s with 3 mA (corneal electrodes) or 2 mA (frontal electrodes) and rats were stimulated twice daily for 4 s at 8 mA (corneal electrodes) or 5 mA (frontal electrodes). With corneal stimulation in rats there was a clear progression of kindling development which was not the same in nature when compared with corneally-stimulated mice. Frontal stimulation did not produce kindling. Moreover, corneal stimulation was better tolerated by rats, while in mice high mortality was seen after either method of current delivery. Our data indicate that frontal electrodes can be used as an alternative to transcorneal stimulation to produce MES by supramaximal or threshold current intensities as screening procedures in antiepileptic drug (AED) development. Nevertheless, this type of stimulation cannot be used to produce minimal electroshock seizures and seems not to be useful to produce kindling in rats and mice.     

Differential effects of kindling and kindled seizures on place learning in the morris water maze

There is some controversy about the role of long-term potentiation (LTP) in spatial learning. The authors have found that triggering generalized kindled seizures with stimulation of the perforant path disrupts spatial learning in the Morris water maze but that kindling per se does not affect spatial learning. It is suggested that abnormal electrical activity induced by high-frequency stimulation of the perforant path may have been responsible for the disruption of spatial learning previously attributed to LTP saturation.     

Fos oncoprotein expression in the rat forebrain following muscimol-induced absence seizures

Fos oncoprotein expression is a marker of neuronal activation following seizures. Here, using this method we examined the anatomical locations of muscimol-induced absence seizures in the rat forebrain. Six hours after a systemic injection of muscimol a massive Fos immunoreactivity appeared in the olfactory system, retrosplenial cortex and paraventricular thalamic nucleus, whereas other cortical areas contained low level of Fos expression. These results provide the first functional morphological evidence suggesting that these forebrain structures with Fos expression may play an important role in the pathophysiology of muscimol-induced absence seizures.     

马桑内酯诱导惊厥发作海马结构内神经元损伤的观察

目的：观察国产中药制剂马桑内酯诱导惊厥发作后，海马结构内神经元损害的范围和特征。方法：采用SD大鼠，马桑内酯单次腹腔内注射诱发惊厥，在发作后不同时间点取脑，行H＆E染色和GFAP免疫组化染色观察海马结构内神经元和神经胶质细胞的改变。结果：海马结构内有显著的神经元损伤。其损伤次序表现为：齿状回、门区和CA3区、CA1区，损伤区周围有反应性星形胶质细胞增生。结论：马桑内酯致惊厥发作后海马神经元的损害与兴奋性细胞毒制剂海仁酸致惊厥具有相似的病理学改变特征，提示国产中药制剂马桑内酯致惊厥与兴奋性细胞毒有关。     

Threshold of seizure activity of the brain and higher nervous activity in the postresuscitation period for intracerebral allotransplantation of fetal neocortex tissue

The threshold of seizure activity of the brain, long-term memory, and learning ability are studied in Wistar rats for bilateral transplantation of fetal nervous tissue in area CA1 of the hippocampus. The grafts are performed on the 2nd, 7th, 14th and 30th days after clinical death caused by asphyxia. A neurotransplantation performed on the 2nd day of the postresuscitation period is found to prevent seizure activity, whereas that performed on the 7th–14th days results in a sharp decline or cessation of spontaneous and induced epileptiform convulsive seizures, prolonged preservation of the long-term memory trace, an improvement of learning ability, and a lessening of defensive and phobic behavior in a large proportion of the animals. Translated fromByulleten's Eksperimental'noi Biologii i Meditsiny, Vol. 121, N ^o 2, pp. 234–237, February, 1996 Presented by V. A. Negovskii, Member of the Russian Academy of Medical Sciences     

小鼠第一次卵裂周期中线粒体分布的变化

用线粒体专一性活体荧光染色剂罗丹明１２３显示小鼠受精卵在第一次卵裂周期中Ｍ的分布变化，雌原核和雄原核在汇合之前，Ｍ在细胞质中呈弥散状随机分布，两原核汇合后，Ｍ在核周围略显聚集，第一次卵裂后期，Ｍ沿纺锤体微管和２个子核周围集中，但在赤道区域内明显稀少，预示出细胞分裂面的定位，这说明细胞质分裂是收综环收缩和细胞结构调整共同作用的结果。２－细胞阶段，Ｍ在细胞核周围明显聚集。２－细胞胚受秋水仙素作用后，Ｍ