Effects of intracerebroventricular injection of histamine on memory deficits induced by hippocampal lesions in rats

This review was conducted to evaluate the long-term prognosis of children responding to vigabatrin by examining the incidence of increased seizure frequency, loss of efficacy, and appearance of new seizures in a cohort of 196 children (mean age, 68.2 months; range, 2 months to 19 years) with drug-resistant epilepsy, who had received vigabatrin as add-on treatment in clinical trials. The results indicate that an increase in seizure frequency was uncommon, occurring in only 10% of children with highly drug-resistant epilepsy and that it usually appears shortly after the initiation of treatment. It was clearly not dose-dependent and most often occurred in patients with nonprogressive myoclonic epilepsy. No specific seizure type was specially involved and usually the problem reversed on discontinuing vigabatrin. Loss of efficacy was also uncommon (12% of patients), and again no specific seizure type was found to be associated. Epilepsy syndrome does seem to be a better predictor of loss of efficacy because it occurred most often in symptomatic generalized epilepsies and cryptogenic infantile spasms. A total of 21 patients (11%) developed genuinely new types of seizures. Fifteen of these patients developed new partial seizures that had little impact on the patients' overall clinical improvement. The new partial seizures were better tolerated than the initial seizure type which in most cases had disappeared. Approximately 3% of patients experienced new generalized seizures that aggravated their initial condition. These occurred most often in patients with nonprogressive myoclonic epilepsy; therefore vigabatrin should be used with particular caution in such patients.     

Problematic standards: improving organizational performance through the assess and improve phases

Since 1987, we have diagnosed 10 patients, 4 males and 6 females, aged 2-11 years at the last evaluation, who all met the following criteria of severe myoclonic epilepsy in infancy (SMEI): generalized or unilateral long-lasting febrile clonic seizures in the first year of life; the subsequent appearance of myoclonic seizures and other types of seizure (partial seizures, atypical absences and convulsive status epilepticus); and neuropsychological deterioration for a certain period. Family histories of epilepsy and febrile seizures could be traced in 1 and 3 cases, respectively. None of them had previous personal history of brain insult. Electroencephalographic (EEGic) recordings in febrile seizure stage were normal; and continuous prophylaxis with phenobarbital failed to prevent the recurrence of febrile seizures. EEG studies in myoclonic stage showed generalized spike-and-waves, polyspike-and-waves, focal abnormalities and/or photosensitivity. The seizures were highly resistant to antiepileptic drugs. Our experiences suggested that comedication of valproic acid, clonazepam and carbamazepine may be most effective in treatment of the diverse seizures including myoclonic seizures, myoclonic-tonic-clonic seizures, atypical absences and partial seizures. Myoclonic seizures and atypical absences diminished in parallel to a clear-cut decrease in generalized abnormalities on EEG in 4 cases aged more than 7 years. However, the partial seizures, secondarily generalized seizures and status epilepticus were still present. Further investigations should aim to identify the underlying etiology and to search more effective treatment.     

Idiopathic epilepsy with generalized seizures in early childhood]

Idiopathic epilepsies with generalized seizures of early childhood are based on a genetic predisposition. The onset takes place between the first and fifth years of age, boys are affected more often than girls. Dependent on the clinical symptomatology you have to distinguish: myoclonic seizures; atonic-astatic seizures; myoclonic-astatic seizures; absences; tonic-clonic seizures. In more than half of the cases a combination of these seizures can be observed. The differentiation of epilepsies with generalized seizures of multifocal origin (infantile spasms, Lennox-Gastaut syndrome and Pseudo-Lennox syndrome [atypical benign epilepsy]) may be difficult but is essential. Therapy of choice is valproate, often in combination with ethosuximide (in children with minor seizures) or with kaliumbromide or phenobarbital (in children with tonic-clonic seizures). Generally the prognosis is more unfavourable if epilepsy starts in the first year of life with afebrile and febrile generalized tonic-clonic or clonic seizures, if children are suffering from longlasting states of seizures and if development is disturbed before beginning of epilepsy.     

Measuring human brain GABA in vivo: effects of GABA-transaminase inhibition with vigabatrin

Gamma-aminobutyric acid (GABA) plays a pivotal role in suppressing the origin and spread of seizure activity. Low occipital lobe GABA was associated with poor seizure control in patients with complex partial seizures. Vigabatrin irreversibly inhibits GABA-transaminase, raising brain and cerebrospinal fluid (CSF) GABA concentrations. The effect of vigabatrin on occipital lobe GABA concentrations was measured by in vivo nuclear magnetic-resonance spectroscopy. Using a single oral dose of vigabatrin, the rate of GABA synthesis in human brain was estimated at 17% of the Krebs cycle rate. As the daily dose of vigabatrin was increased to up to 3 g, the fractional elevation of brain GABA was similar to CSF increase. Doubling the daily dose from 3 to 6 g failed to increase brain GABA further. Increased GABA concentrations appear to reduce GABA synthesis in humans as it does in animals. With traditional antiepileptic drugs, remission of the seizure disorder was associated with normal GABA levels. With vigabatrin, elevated CSF and brain GABA was associated with improved seizure control. Vigabatrin enhances the vesicular and nonvesicular release of GABA. The release of GABA during seizures may be mediated in part by transporter reversal that may serve as an important protective mechanism. During a seizure, this mechanism may be critical in stopping the seizure or preventing its spread.     

Randomized trial comparing vigabatrin and hydrocortisone in infantile spasms due to tuberous sclerosis

Vigabatrin has been shown to be efficient in infants with infantile spasms and tuberous sclerosis, in open studies. In order to compare vigabatrin to oral steroids, a prospective randomized multicenter study was implemented using both drugs as monotherapy in newly diagnosed patients with infantile spasms and tuberous sclerosis. Eleven infants received vigabatrin (150 mg/kg per day) and 11 hydrocortisone (15 mg/kg per day) for 1 month. Spasm free patients continued vigabatrin or progressively stopped hydrocortisone in 1 month, non-responders were crossed to the other drug for a new 2 month-period. All vigabatrin patients (11/11) were spasm-free versus 5/11 hydrocortisone infants (P < 0.01). Seven patients were crossed to vigabatrin (six for inefficacy, one for adverse events) and became also totally controlled. Mean time to disappearance of infantile spasms was 3.5 days on vigabatrin versus 13 days on hydrocortisone (P < 0.01). Five patients exhibited side effects on vigabatrin but nine on hydrocortisone (P = 0.006). Vigabatrin should therefore be considered as the first choice treatment for infantile spasms due to tuberous sclerosis.     

Anti-viral effect of interferon-alpha on bovine viral diarrhea virus

PURPOSE: Lamotrigine (LTG) is recognised as effective add-on therapy for focal epilepsies, but this is the first double-blind, placebo-controlled, crossover study in treatment-resistant generalised epilepsy. METHODS: The study consisted of 2 x 8-week treatment periods followed by a 4-week washout period. Patients received doses of either 75 or 150 mg daily, depending on their concomitant antiepileptic drugs (AEDs). Long-term continuation was offered at the end of the study with open-label LTG. RESULTS: Five centres in Australia recruited 26 patients who were having absence, myoclonic, or generalized tonic-clonic seizures or a combination of these. Twenty-two patients completed the study. There was a significant reduction in frequency of both tonic-clonic and absence seizure types with LTG. A 350% decrease in seizures was observed for tonic-clonic seizures in 50% of cases and for absence seizures in 33% of evaluable cases. Rash was the only adverse effect causing discontinuation. Twenty-three of 26 opted for open-label LTG, with 20 still receiving LTG for a mean of 26 months. In these 20, 80% had > or =50% seizure reduction and five (25%) were seizure free. CONCLUSIONS: This study shows that LTG is effective add-on therapy in patients with refractory generalised epilepsies. Statistically significant reduction in seizures in both absence and tonic-clonic seizure types was seen even with low doses of LTG.     

Idiopathic generalised epilepsy in adults manifested by phantom absences, generalised tonic-clonic seizures, and frequent absence status

OBJECTIVES: To describe the clinical and EEG features of adult patients with very mild absences, late onset generalised tonic clonic seizures, and frequent absence status. METHODS: Patients were referrals to a clinic for epilepsies. They all had clinical assessment and EEG, video EEG, or both for documentation of absences. RESULTS: Of 86 adults with idiopathic generalised epilepsies and EEG/video-EEG documented absences, 13 patients showed similar clinico-EEG features with: (a) "phantom absences" consisting of mild ictal impairment of cognition associated with brief (3-4 s), generalised 3-4 Hz spike/multiple spike and slow wave discharges; (b) infrequent, mainly late onset, generalised tonic clonic seizures, and (c), absence status which occurred in six of them either in isolation or terminating with generalised tonic clonic seizures. None of the patients had myoclonic jerks or photosensitivity. Two patients were father and daughter and another patient had a family history of infrequent generalised tonic clonic seizures. CONCLUSION: It seems that this is an idiopathic generalised epilepsy syndrome in adults which has not been previously recognised.     

Role of vigabatrin and lamotrigine in treatment of childhood epileptic syndromes

PURPOSE: Vigabatrin (VGB) and lamotrigine (LTG) are two new antiepileptic drugs (AEDs) with different mechanisms of action for treatment of refractory epilepsies. Previous reports have indicated efficacy of both drugs in a number of epileptic syndromes. METHODS: We compared these new AEDs drugs to determine their respective efficacy against different types of epileptic syndrome and to develop a rational approach to their use. We reviewed the charts of 105 children, with partial and generalized epilepsies. RESULTS: VGB was to be significantly more effective in children with partial epilepsies, and LTG was more effective in those with generalized epilepsies. CONCLUSIONS: VGB and LTG have different therapeutic profiles. Combination treatment with the two drugs may represent rational polytherapy for patients with epilepsy resistant to treatment with either drug alone or as add-on to other AED treatment.     

Single-chain Fv with manifold N-glycans as bifunctional scaffolds for immunomolecules

PURPOSE: To investigate the significance of cortical pathology of tonic spasms in patients with tuberous sclerosis. METHODS: The subjects were 38 patients with epilepsy associated with tuberous sclerosis. We analyzed ictal EEGs of tonic spasms and partial seizures by means of video-EEG monitoring for a total of 763 tonic spasms in 20 patients and 107 partial seizures in 15 patients. We also investigated the relation between partial seizures and magnetic resonance imaging (MRI) findings of these patients. RESULTS: Ictal EEG patterns of tonic spasms were divided into generalized and focal patterns. Thirteen patients had only generalized patterns, whereas seven had both patterns. In five patients who had focal ictal patterns of tonic spasms and partial seizures, the location of focal patterns corresponded with the location of onset of partial seizures. Focal discharges were seen immediately before, after, and in the middle of tonic spasms in series in 13 patients. The location of focal discharges also corresponded with the location of the onset of partial seizures in 10 of the 13 patients. Regarding partial seizures, four patients had multiple active epileptogenic foci during the same period, and two others had shifting epileptogenic foci with increasing age. CONCLUSIONS: These findings indicate that cortical pathology plays an important role in the occurrence not only of partial seizures but also of tonic spasms in patients with tuberous sclerosis.     

Clonazepam: a review of its pharmacological properties and therapeutic efficacy in epilepsy

Clonazepam or 5-(2-chlorphenyl)-1, 3-dihydro-7-nitro-2H-1,4benzodiazepin-2-one, is a close structural and pharmacological relative of nitrazepam. It has a broad spectrum of activity against the various types of epilepsy, and is effective in many patients whose condition has proved resistant to other antiepileptic drugs. Its chief uses are in status epilepticus, in which intravenous clonazepam may replace diazepam as the drug of first choice, and in the minor motor seizures of childhood, particularly petit mal absences, the Lennox-Gastaut syndrome and infantile spasms. Clonazepam is also at least as effective as current treatment in psychomotor and myoclonic epilepsies, but seems unlikely to replace phenytoin and the barbiturates in the treatment of grand mal or focal motor seizures except in patients resistant to standard therapy. Initial success with clonazepam can be followed by loss of effect, but benefit can often be restored, at least initially, by temporary interruption and re-institution of treatment. Side-effects are common with clonazepam. Most patients experience drowsiness and fatigue, which are frequent causes of withdrawal, together with lesser incidences of ataxia, dystonia, hypotonia, and hyperactivity. These effects usually disappear with continued therapy, and are minimised by gradual introduction of the drug over 2-4 weeks. Hypersalivation and excessive bronchial secretion may be a problem in children and infants.     

Ergonomics: where have we been and where are we going: IV

The long-term prognosis of 185 children with epilepsy, who continued to attend the Clinic for Epileptic Children, the Department of Pediatrics, the University of Tokyo, beyond the age of 18 years, was reported. The length of follow-up varied from three to 20 years, but most of them were followed longer than 10 years. The presumed etiology in these children was divided into a cryptogenic group (124, 67.0%) and a symptomatic group (61). The types of seizures were classified into grand mal (86 cases), focal seizure (27), petit mal absence (4), psychomotro seizure (5), infantile spasms (7), and so on. It may be noted that the highest frequency of grand mal was demonstrated, while the incidences of infantile spasms, myoclonic seizure, and akinetic seizure were low in the series. Only 28 children (15.1%) had complications of physical and/or mental handicaps. The follow-up study revealed that 140 patients (75.7%) had been seizure-free in the last 12 months. One hundred and fifteen of them had no seizures for five years or longer. On the other hand, electroencephalographic abnormalities generally continued for a long time after disappearance of seizures. Eightly-one of well-controlled patients were gradually decreasing the doses of anticonvulsants. As for seizure types, it is noted that focal seizure, psychomotor seizure, and infantile spasms were relatively difficult to be controlled. Except for 27 patients, most of them attended normal schools, including junior colleges or universities, and engaged in various occupations. Fifteen female patients had already married, and out of 13 babies who were born from these patients, there were one with ventricular septal defect, one with mental deficiency, and one with anencephaly, while the rest were entirely normal. Additional problems on withdrawal of anticonvulsants after a long-term seizure-free period, and what a medical system should be for treatment of epilepsy in children up to their adulthood were discussed.     

Effectiveness of vigabatrin against focally evoked pilocarpine-induced seizures and concomitant changes in extracellular hippocampal and cerebellar glutamate, gamma-aminobutyric acid and dopamine levels, a microdialysis-electrocorticography study in freely moving rats

Limbic seizures were evoked in freely moving rats by intrahippocampal administration of the muscarinic agonist pilocarpine via the microdialysis probe (10 mM for 40 min at 2 microl/min). This study monitored changes in extracellular hippocampal gamma-aminobutyric acid (GABA), glutamate and dopamine levels after systemic (30 mg/kg/day) or local (intrahippocampal or intranigral, 5 mM or 600 microM for 180 min at 2 microl/min) vigabatrin administration, and evaluated the effectiveness of this antiepileptic drug against pilocarpine-induced seizure activity. Extracellular GABA and glutamate overflow in the ipsilateral cerebellum was studied simultaneously. Microdialysis was used as an in vivo sampling technique and as a drug-delivery tool. Electrophysiological evidence for the presence or absence of seizures was recorded with electrocorticography. The observed alterations in extracellular hippocampal amino acid levels support the hypothesis that muscarinic receptor stimulation by the intrahippocampal administration of 10 mM pilocarpine is responsible for the seizure onset, and that the amino acids maintain the sustained seizure activity. The focally evoked pilocarpine-induced seizures were completely prevented by intraperitoneal vigabatrin premedication for 7 days or by a single intraperitoneal injection. Effective protection was reflected in a lack of sustained elevations of hippocampal glutamate levels. Rats receiving vigabatrin intrahippocampally or intranigrally still developed seizures, although there appeared to be a partial protective effect. During the intrahippocampal perfusion with 5 mM vigabatrin, extracellular hippocampal GABA levels increased, whereas the extracellular glutamate and dopamine overflow decreased. The lack of a complete neuroprotection after local vigabatrin treatment is discussed.     

Typical absence status in adults: diagnostic and syndromic considerations

PURPOSE: To study the electroclinical features of typical absence status (TAS) in adults with syndromes of idiopathic generalized epilepsies (IGEs). METHODS: Twenty-one patients with one or more spells of TAS were identified among 136 consecutive adult patients with IGEs. All patients with TAS had comprehensive electroclinical investigations and EEG or video-EEG recorded absences. RESULTS: TAS occurred in 24.4% of 86 patients who had IGEs with typical absences alone or in combination with other seizures presisting in adult life. The prevalence of TAS appeared to be syndrome related, ranging from as high as 57.1% in perioral myoclonia with absences and 46.2% in "phantom" absences with GTCS to as low as 6.7% in juvenile myoclonic epilepsy. A varying degree of impairment of cognition was the cardinal clinical symptom shared in all TAS, but corresponding syndromes of IGE were often betrayed by other symptoms such as eyelid or perioral myoclonia. In phantom absences with GTCS, TAS was more numerous (p < or = 0.05) and more frequently the first overt seizure type (p = 0.006) than in any other IGE. Only in the syndrome of eyelid myoclonia with absences, TAS was always situation related, mainly as a result of antiepileptic drug discontinuation. CONCLUSIONS: The clinical EEG semiology and prevalence of TAS appear to be syndrome related with the highest prevalence in the syndromes of perioral myoclonia with absences and phantom absences with GTCS (p = 0.0024).     

Efficacy of topiramate

In controlled clinical trials, topiramate (Topamax) has demonstrated efficacy in refractory patients with complex partial seizures and secondarily generalized tonic-clonic seizures. Approximately 45 percent of 534 patients had a > or = 50 percent reduction in seizure frequency. Limited open label trials have shown that topiramate has broad spectrum activity and may be effective in patients with primary generalized epilepsies. The efficacy of topiramate compares very favourably with the efficacy of other new antiepileptic drugs recently introduced.     

Epilepsy in early development: the lesson from surgery for early intractable seizures

This report examines the impact on development and the problems involved in assessing development in very young children with early-onset intractable seizures, particularly infantile spasms. A review of studies on medically and surgically treated children with infantile spasms underscores the relationship between seizure control and developmental outcome. About 50% of children with markedly intractable infantile spasms attained seizure control and significant improvement in the use of nonverbal communication, a developmental measure that has been used in other populations of developmentally delayed children. With the exception of duration of illness, clinical measures of age of onset of infantile spasms, type of surgery, and side of surgery did not appear to be related to the postoperative change in nonverbal communication. The neuropathology findings of surgically treated children with infantile spasms suggest that the underlying pathology occurs early in brain development. In conclusion, the cumulative effect of uncontrolled seizures and the underlying pathology might impact the early development of children with intractable infantile spasms.     

Rhabdomyolysis in transplant patients

In a retrospective analysis of all our patients with seizure onset prior to age 16 years, 25 patients with primary generalized tonic (n = 10) or tonic-clonic (n = 15) seizures were identified. These patients constituted 5.7% of the total seizure patient population in our institute between the ages of 1 month and 16 years. The natural history of generalized tonic-clonic seizures is known to be benign; however, that of isolated primary generalized tonic seizures is not clear. Therefore, an attempt was made to characterize the patients suffering from primary generalized tonic seizures and determine their outcome. Analysis of our patient population shows that both seizure types are characterized by early onset of generalized seizures that appear in normally developed children with a normal electroencephalographic background. The children usually respond quickly to antiepileptic drugs. A long-term follow-up (mean period of 7.6 years) was possible in 84% of the patients, and showed that 95% of them were seizure free at the end of the follow-up period. There was no significant difference between the two groups in regard to age of onset, family history, and seizures at follow-up. In conclusion, the natural history of patients with generalized tonic seizures is similar to the benign course of those with generalized tonic-clonic seizures.     

Therapeutic efficacy of ACTH in symptomatic infantile spasms with hypsarrhythmia

The records of twenty-six infants with both symptomatic infantile spasms and classic hypsarrhythmia were reviewed to determine the efficacy of various ACTH dosages and time of initiation of therapy. Mean age of infantile spasm onset was 6.4 months. Most patients (13) had sustained perinatal hypoxic-ischemic insults. Seventeen patients (65%) had complete cessation of spasms. Between these responders and the 9 nonresponders there was no difference in duration of spasms prior to treatment (2.6 and 2.0 months) or mean ACTH dose (87.4 and 84.5 U/m2, respectively). Infants treated with high-dose ACTH (> 100 U/m2) did not have an improved response rate. The most favorable outcomes were associated with spasm onset at > 8 months of age (all of whom were responders, regardless of dose) or when treatment was started within 1 month of onset of infantile spasms with > 80 U/m2 ACTH (88% responders). Infants treated more than 2 months after onset often did not respond (57%) regardless of dose. Nonresponders with spasm onset at < 4 months of age had the worst prognoses; all had poorly controlled seizures and regressed developmentally. Although all infants in the study were neurologically abnormal, development either improved or did not deteriorate in most responder infants following spasm resolution and one-half remained seizure free. Nonresponder infants continued to have infantile spasms or other seizure types. These data suggest that ACTH is valuable in the treatment of significantly impaired infants with symptomatic infantile spasms, but the most important determinants of outcome may be age of onset and rapidity of treatment rather than dosage.     

L-deprenyl (selegiline) exerts anticonvulsant effects against different seizure types in mice

L-Deprenyl (selegiline), a selective inhibitor of monoamine oxidase type B, has recently been shown to exert anticonvulsant and antiepileptogenic effects in the kindling model of partial (focal) epilepsy. In the present study, we examined if L-deprenyl exerts anticonvulsant effects in standard rodent models of generalized seizures. In addition to anticonvulsant activity, behavioral effects induced by L-deprenyl were monitored closely. To assess the stereoselectivity of anticonvulsant and behavioral effects of deprenyl, the D-enantiomer was included in the studies. Furthermore, the antiepileptic drug phenobarbital was used for comparison. The following tests were performed in mice: 1) the threshold for tonic electroconvulsions; 2) the maximal electroshock seizure test with fixed supramaximal (suprathreshold) stimulation; 3) the threshold for myoclonic, clonic and tonic seizures in response to i.v. infusion of pentylenetetrazole (PTZ); 4) the s.c. PTZ seizure test, with a fixed dose of PTZ (80 microgram/kg) for seizure induction; 5) the rotarod and chimney tests for determination of motor impairment. Furthermore, animals were observed in cage and open field for stereotyped behavior and other behavioral abnormalities. L-Deprenyl, tested at doses of 1 to 40 microgram/kg i.p., significantly increased myoclonic and clonic PTZ thresholds and the threshold for tonic electroconvulsions, whereas D-deprenyl was either ineffective or exhibited a lower anticonvulsant potency than L-deprenyl. Both drugs were ineffective in the maximal electroshock seizure and s.c. PTZ seizure tests. In contrast to the higher anticonvulsant potency of L-deprenyl in seizure threshold tests, D-deprenyl was more potent than L-deprenyl to induce behavioral abnormalities, such as hyperlocomotion. The data indicate that L-deprenyl exerts anticonvulsant activity against different seizure types. This anticonvulsant activity and the previously reported neuroprotective and cognition-enhancing action of L-deprenyl offer a unique combination of drug effects which might be of clinical benefit in patients with epilepsy.     

Myoclonic absence-like seizures and chromosome abnormality syndromes

PURPOSE: We explored the relationship between myoclonic absence seizures (MAS) and underlying chromosome disorders. METHODS: Among 14 patients with MAS observed in three centers, 5 had typical cryptogenic myoclonic absence epilepsy (MAE), 2 had MAS associated with other seizure types (1 with signs of a neuronal migration abnormality and 1 with signs of a metabolic disorder), and 7 had MAS, with or without other seizure types, complicating a chromosome abnormality syndrome-2 with trisomy 12p, 4 with Angelman syndrome, and 1 with inv dup (15). RESULTS: In the 7 patients with chromosomopathy, MAS appeared at a mean age of 2.9 years (range 4 months to 6 years 6 months), had a duration of 4-20 s, and were accompanied by reduced awareness and rhythmic myoclonic jerks involving proximal limb muscles. Ictal EEG showed 2- to 3-Hz generalized spike-and-wave discharges. CONCLUSIONS: In these patients, MAS differed slightly from those of typical MAE: age of onset was earlier, absences were of shorter duration, and no clear increase in muscular tone was noted. Abnormal expression of genes codifying for the subfamily of K+ channels and for gamma-aminobutyric acid-3 subunit receptors (GABRB3), both located in the chromosome segments involved in the chromosomopathies presented by our patients, could be responsible for the same generalized seizure type. Chromosome analysis should be performed in patients with mental retardation and MAS, especially when the ictal pattern does not completely overlap that observed in MAE.