Clinical Efficacy of New Antiepileptic Drugs in Refractory Partial Epilepsy: Experience in the United States With Three Novel Drugs

Summary: A number of new antiepileptic drugs (AEDs), including topiramate (TPM), felbamate (FBM), and gabapentin (GBP), are approved or believed to be close to approval for marketing in the United States. Key efficacy findings for these AEDs in refractory partial epilepsy were reviewed. Large and significant drug-placebo differences were observed with TPM in two large dose-finding trials conducted in the United States. The minimal effective dose of TPM in the population studied was determined to be approximately 200 mg/day, and doses above 600 mg/day produced good efficacy but little incremental benefit versus the lower dosages for the overall study population. FBM is active in partial epilepsy, although seizure reduction is less marked and drug interactions complicate the findings. GBP is also active in this population, but only the 1,800 mg/day dosage was significantly better than placebo with respect to percent re-sponders. It may be useful to explore higher dosage ranges for both FBM and GBP if they can be well tolerated.     

A new and highly sensitive method for measuring 3-methoxytyramine using HPLC with electrochemical detection. Studies with drugs which alter dopamine metabolism in the brain

3-Methoxytyramine (3-MT) is a minor metabolite of dopamine which is suggested to reflect the turnover and utilization of dopamine. A novel, isocratic HPLC method has been developed which can be used to analyse 3-MT in homogenates of rat brain without the need for additional purification procedures. Furthermore, the coulometric electrochemical detection system is sensitive enough to measure 3 pg of 3-MT (equivalent to 0.6 ng/g tissue wet weight). 3-Methoxytyramine was measured in the striatum and n. accumbens after decapitation and rapid freezing, using 3-methoxy-4-hydroxybenzylamine as the internal standard. The effects of dopaminergic and other drugs on this metabolite were examined using this method. -Methyl-p-tyrosine (200 mg/kg i.v.) produced parallel linear decreases in dopamine and 3-MT in naive rats, but not those pretreated with tranylcypromine (5 mg/kg i.p.). Methamphetamine (0.3–10 mg/kg i.p.) and amphetamine (0.3–10 mg/kg i.p.) both dose-dependently increased 3-MT in naive and tranylcypromine-pretreated rats. In naive animals, 3-MT was not altered by intraperitoneal injection of the dopamine reuptake inhibitors, bupropion (10 mg/kg) and nomifensine (10 mg/kg) or by sibutramine HCl (3 mg/kg), amitriptyline (10 mg/kg), desipramine (10 mg/kg) and zimeldine (10 mg/kg). 3-Methoxy-tyramine was decreased by apomorphine (5 mg/kg i.p.) and also by large doses of the selective D₂ antagonist, BRL 34778 (5 mg/kg i.p.) or -DOPA (50 mg/kg i.p.). The selective D₁ antagonist, SCH 23390 (0.1 or 5 mg/kg i.p.) was without effect. In tranylcypromine-pretreated rats, 3-MT was dose-dependently reduced and increased by apomorphine (0.01–5 mg/kg i.p.) and BRL 34778 (0.1–5 mg/kg i.p.), respectively. The drug SCH 23390 (0.1–5 mg/kg i.p.) produced much smaller increases in 3-MT which were probably mediated through the striatonigral pathway. Overall, the data suggest that measurement of 3-MT, after inhibition of monoamine oxidase, is a useful index of the release and utilization of dopamine. However, after substantial and prolonged depletion of dopamine, levels of 3-MT in naive animals are a better index. Also, the formation of 3-MT in naive rats provides a sensitive method for distinguishing between dopamine releasing agents and reuptake inhibitors.     

Pharmacokinetics and haemodynamic effects of ISDN following different dosage forms and routes of administration

The pharmacokinetics and haemodynamic effects of isosorbide dinitrate (ISDN) have been investigated following administration of single doses as a sublingual (SL) spray (2.5 mg), sublingual tablet (5 mg) and peroral tablet (10 mg) in a randomised, placebo-controlled double-blind cross-over trial in 16 healthy volunteers.After the sublingual spray C_max was higher (39.0 ng·ml^-1) and t_max was shorter (3.9 min) than after the sublingual (22.8 ng·ml^-1 and 13.8 min) and peroral (16.9 ng·ml^-1 and 25.6 min) tablets. The AUC of ISDN did not differ following any of the three formulations (1031; 879; 997 ng·ml^-1·min, for the spray, SL tablet and PO-tablet, respectively). Mononitrate metabolites of ISDN (IS-2-MN and IS-5-MN) and total nitrates in plasma increased in proportion to the administered dose. This indicates that the fraction of the dose absorbed was the same for all the formulations but that the extent of first-pass metabolism increased in the order sublingual spray < sublingual tablet < peroral tablet. Thus, compared to the spray, the relative bioavailability of ISDN was 48% and 28% from the sublingual and peroral tablets, respectively.The haemodynamic effects were quantified using the a/b ratio of the finger pulse wave and the systolic blood pressure and heart rate under orthostatic conditions. For the a/b ratio of the finger pulse, the maximal effect was higher (e_max=130%) and the time to e_max (t_emax) shorter (16.6 min) after the spray than the sublingual tablet (84.4% and 25.5 min) or peroral tablet (90.2 and 31.3 min). The onset of effect was within 3, 5 and 7.5 min after the spray, sublingual and peroral tablets, respectively. A larger change in the orthostatically-induced decrease in systolic blood pressure and increase in heart rate was obtained following peroral than sublingual administration despite the similar plasma concentrations of ISDN. This probably reflects the larger amount of pharmacodynamically active mononitrate metabolites formed after oral dosing. The integrated effect following administration of 2.5 mg ISDN as spray was similar to that of a sublingual tablet of 5 mg.     

The use of experimental studies to reveal suspected neurotoxic chemicals as occupational hazards: acute and chronic exposures to organic solvents.

The nervous system differs from many other body organs by its central control of vital functions and its low regeneration capacity. Organic solvents have, as a group, been suspected to have neurotoxic effects. Because of their similar physical properties and the fact that in industrial uses, they are often present in various mixtures, organic solvents have also been regarded, unfortunately, to induce common neurotoxic effects. However, it is evident from experimental studies using specified exposure conditions that different organic solvents have very diverse neurotoxic effects and also that the toxic mechanism may differ between acute and chronic exposure. No specific method used to describe a neurotoxic effect or single toxic response can be used for the overall occupational risk assessment of all organic solvents. Each solvent has to be considered as having its own unique toxic effects.     

河南省地方性高碘甲状腺肿的发现、流行特征及其干预研究

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中西医结合治疗缺血性脑血管病临床疗效观察

目的 回顾性分析中西医结合治疗缺血性脑血管病的疗效。方法 对126例缺血性脑血管病患者，在早期西医溶栓、抗凝、降低血液粘度、扩张血管和促进脑细胞代谢等治疗基础上，结合中医辩证施治治疗。结果 42例瘫肢肌力恢复达V级；48例肌力≥Ⅳ级，言语流畅；27例生活能基本自理，可依杖散步，肌力≥Ⅲ级：9例与治疗前对比肌力提高Ⅰ～Ⅱ级，但生活仍不能自理。结论 在西药治疗基础上，结合益气活血中药调理可显著提高患者的疗效。     

股骨干骨折扩髓腔髓内钉固定对凝血机能和肺换气功能的影响

【目的】探讨股骨干骨折扩髓与不扩髓髓内钉固定对凝血机能和肺换气功能的影响。【方法】 38例股骨干骨折分别采用扩髓 (RFN)和不扩髓 (UFN)髓内钉固定 ,在手术开始前至术后 4 8h内 7个不同时间段监测血小板、纤维蛋白原、凝血酶原时间 (PT)和部分凝血活酶激活时间 (APTT)的变化 ,并动脉血气分析 ,计算肺泡 动脉血氧分压递差 [P(A aDO2 ) ]。【结果】RFN组 ,扩髓后血小板开始减少 ,P(A aDO2 )升高 (P<0 0 5 ) ;髓钉插入后 30min纤维蛋白原减少 ,PT、APTT延长 (P <0 0 5 ) ;UFN组表现出同样的趋势 ;两组中各项指标均在 2 4～ 4 8h内恢复正常 ;动脉血气分析各时间段和组间差异无显著性 (P >0 0 5 )。【结论】扩大髓腔的髓内钉固定 ,和不扩髓相比 ,并不影响肺换气功能 ,对凝血机能的影响是一个自限过程 ,单纯股骨干骨折 ,可耐受扩髓固定手术。     

The discriminative stimulus and subjective effects of d-amphetamine,phenmetrazine and fenfluramine in humans

The discriminative stimulus (DS) and subjective effects of d-amphetamine (AMP), phenmetrazine (PMT) and fenfluramine (FFL) were studied in a group of normal healthy adults. Subjects (N=27) were trained to discriminate between placebo and 10 mg AMP (PO). Fourteen of the subjects (discriminators) reliably learned the discrimination, whereas the other 13 did not. Nearly all discriminators labelled AMP as a stimulant, and AMP, relative to placebo, increased ratings of drug liking and general activity level, and produced typical stimulant-like subjective effects, as measured by the Profile of Mood States, the Addiction Research Center Inventory, and a series of visual analog scales. The discrimination accuracy of discriminators increased as a function of hour after drug ingestion, as did analog ratings of how certain subjects were that their discrimination responses were correct. Discriminators were tested with doses of PMT (25 and 50 mg) and FFL (20 and 40 mg) to determine whether the DS properties of these drugs would substitute for those of AMP. Both doses of PMT consistently substituted for AMP, and PMT produced subjective effects very similar to those of AMP. Conversely, neither dose of FFL consistently substituted for AMP, and FFL produced essentially no subjective effects. These findings are consistent with results from discrimination studies with other species, and provide further evidence of the validity of this procedure for studying the DS properties of drugs in humans. Offprint requests to: L.D. Chait     

Occurrence and Distribution of Bone Tumors in Beagle Dogs Exposed to 90Sr

Radiation-induced bone tumors in beagle dogs exposed to ⁹⁰Sr have been evaluated in terms of their incidence, time of appearance, occurrence as multiple tumors, anatomic distribution, and the influence of sex on their development. Among dogs fed ⁹⁰Sr during skeletal development, the incidence of bone tumors was dose dependent. Tumors thus appeared in 10 of 19 dogs receiving average skeletal doses of 130 Gy, 15 of 60 receiving 97 Gy, 5 of 61 receiving 61 Gy, 2 of 65 receiving 26 Gy, and 1 of 40 receiving 1.3 Gy. No tumors appeared among 66 dogs who received 8 Gy, 78 who received 0.3 Gy, and 80 non-irradiated controls, all of which have been observed for life. Among dogs given a single intravenous injection of ⁹⁰Sr in early adulthood, tumor production was somewhat higher than among ⁹⁰Sr-fed dogs at the same radiation dose: bone tumors were present in 6 of 25 dogs who received 62 Gy and 1 of 20 dogs who received 7.5 Gy. Bone tumors appeared sooner and were more often multiple in animals receiving the higher doses. Long bones were the sites of most of the tumors appearing after the highest dose level. Bones of the head, particularly the mandible, were the predominant site of tumors in the next highest dose level group.     

果酸疗法在痤疮治疗中的应用

目的：评价果酸（羟基乙酸）治疗痤疮的临床疗效和安全性,掌握果酸治疗的适应证及方法。方法：应用浓度为20%、35%、50%、70%的羟基乙酸治疗24例痤疮患者,采用自身前后对照进行疗效观察。结果：23例患者完成治疗。4周后皮损减退率34%,有效率83%;8周后12例患者皮损减退率53%,有效率100%;12周后5例患者皮损减退率69%,有效率100%;炎性皮损减退率高于非炎性皮损。结论：果酸治疗痤疮至少需要4周,且安全有效。