Adult and pediatric physiologically-based biopharmaceutics modeling to explain lamotrigine immediate release absorption process

Physiologically-based biopharmaceutics modeling (PBBM) has potential to accelerate the development of new drug and formulations. An important application of PBBM is for special populations such as pediatrics that have pharmacokinetics dependent on the maturation process. Lamotrigine (LTG) is a Biopharmaceutics Classification System (BCS) II drug and is widely prescribed. Therefore, the goal of this study was to assess the biopharmaceutics risk of the low-soluble drug LTG when the ontogeny on gastrointestinal tract (GIT) physiological parameters are considered. An oral physiologically-based pharmacokinetic model and a PBBM were developed and verified using GastroPlus™ software for both adults and children (2-12 years old, 12-52 kg). The biopharmaceutics properties and GIT physiological parameters were evaluated by sensitivity analysis. High doses were simulated assuming a worst case scenario, that is, the dose of 200 mg for adults and 5 mg/kg (up to the maximum of 200 mg) for 2-year-old children. Although several authors have suggested that ontogeny may have an effect on gastrointestinal fluid volume, our study found no evidence of interference between fluid and dose volumes with in vivo dissolution of LTG. The most impactful parameter was found to be the gastric transit time. Therefore, the hypothesis is developed to examine whether LTG exhibits characteristics of a BCS II classification in vitro while showing BCS I-like behavior in vivo. This hypothesis could act as a base for conducting novel studies on model-informed precision dosing, tailored to specific populations and clinical conditions. In addition, it could be instrumental in assessing the influence of various release profiles on in vivo performance for both adult and pediatric populations.

Long-Term Outcome of Temporal Lobe Epilepsy Surgery in 621 Patients With Hippocampal Sclerosis: Clinical and Surgical Prognostic Factors

Temporal lobe epilepsy (TLE) is the most common type of focal epilepsy and is frequently drug-resistant (DR) to antiseizure medication (ASM), corresponding to approximately one-third of the cases. When left inadequately treated, it can worsen the quality of life, cognitive deficits, and risk of death. The standard treatment for drug-resistant TLE is the surgical removal of the structures involved, with good long-term outcome rates of 60–70 % and a low rate of adverse effects. The goal of successful treatment is sustained seizure freedom. In our study, we evaluated sustained long-term (up to 23 years) surgical outcomes in 621 patients with DR-TLE associated with hippocampal sclerosis, who underwent a temporal lobectomy. We analyzed the main predictive factors that influence the surgical outcome related to seizure control, through a longitudinal and retrospective study, using a multivariable regression model. We found that 73.6% of the patients were free from disabling seizures (Engel Class I), maintained over time in 65% of patients followed up to 23 years after surgery. We found that four independent variables predicted seizure outcomes. The presence of dysmnesic and olfactory aura predicted a less favorable outcome. The history of febrile seizure and the surgical technique predicted a good outcome. Regarding the type of surgical technique, the standard anteromesial temporal lobectomy (ATL) led to significantly better outcomes (78.6% Engel Class I) when compared to the selective amygdalohippocampectomy via subtemporal approach (67.2% Engel Class I; p = 0.002), suggesting that the neuronal networks involved in the epileptogenic zone may be beyond mesial temporal structures. The multivariable regression model with the above-mentioned predictor variables revealed an ExpB = 3.627 (N = 621, p < 0.001), indicating that the model was able to distinguish between patients with a seizure-free. We conclude that epilepsy surgery is a safe procedure, with low rates of postoperative complications and good long-term results.

Hypoxemia following generalized convulsive seizures

Objective

To analyze the factors that determine the occurrence or severity of postictal hypoxemia in the immediate aftermath of a generalized convulsive seizure (GCS).

Methods

We reviewed the video-EEG recordings of 1,006 patients with drug-resistant focal epilepsy included in the REPO2MSE study to identify those with ≥1 GCS and pulse oximetry (SpO2) measurement. Factors determining recovery of SpO2 ≥ 90% were investigated using Cox proportional hazards models. Association between SpO2 nadir and person- or seizure-specific variables was analyzed after correction for individual effects and the varying number of seizures.

Results

A total of 107 GCS in 73 patients were analyzed. A transient hypoxemia was observed in 92 GCS (86%). Rate of GCS with SpO2 <70% dropped from 40% to 21% when oxygen was administered early (p = 0.046). Early recovery of SpO2 ≥90% was associated with early administration of oxygen (p = 0.004), absence of postictal generalized EEG suppression (PGES) (p = 0.014), and extratemporal lobe epilepsy (p = 0.001). Lack of early administration of O2 (p = 0.003), occurrence of PGES (p = 0.018), and occurrence of ictal hypoxemia during the focal phase (p = 0.022) were associated with lower SpO2 nadir.

Conclusion

Postictal hypoxemia was observed in the immediate aftermath of nearly all GCS but administration of oxygen had a strong preventive effect. Severity of postictal hypoxemia was greater in temporal lobe epilepsy and when hypoxemia was already observed before the onset of secondary GCS.

An investigation of the influence of patient-related factors and comedications on lamotrigine clearance in patients with epilepsy

Lamotrigine (LTG) is one of the most widely used antiepileptic drugs. Confusion still exists in the literature as to the relative influence of age, body weight, and concomitant drug therapy on LTG pharmacokinetics. So, the objective of this study is to evaluate the influence of patient-related factors and comedication on LTG apparent oral clearance (CL/F). A therapeutic drug-monitoring database was used to identify steady-state plasma LTG concentrations in 210 patients. LTG CL/F values were calculated for each patient according to the equation CL/F (L/h per kg) = LTG daily dose (mg/kg)/Css (steady state concentration) (mg/L) × 24 h. A linear-regression model was used to assess the influence of gender, dose, age, and body weight in LTG CL/F. The influence of comedication on LTG CL/F was investigated by applying the Bonferroni post-test. The lowest LTG CL/F was found in patients comedicated with valproate (VPA) (mean, 0.0183 L/h per kg), followed by patients receiving VPA + enzyme inducers (0.0271 L/h per kg), patients on LTG monotherapy (0.0298 L/h per kg) and patients comedicated with enzyme inducers (0.056 L/h per kg) LTG CL/F correlated significantly with LTG dose (P < 0.01), but showed no significant relationship with gender, weight, and age. LTG CL/F is influenced by the type of antiepileptic comedication. The correlation with dose may be a spurious finding related to the fact that physicians, in adjusting dosage according to clinical response, are more likely to use larger doses in patients with high clearance values.

Risk factors of postictal generalized EEG suppression in generalized convulsive seizures

OBJECTIVE

To identify the clinical determinants of occurrence of postictal generalized EEG suppression (PGES) after generalized convulsive seizures (GCS).

METHODS

We reviewed the video-EEG recordings of 417 patients included in the REPO2MSE study, a multicenter prospective cohort study of patients with drug-resistant focal epilepsy. According to ictal semiology, we classified GCS into 3 types: tonic-clonic GCS with bilateral and symmetric tonic arm extension (type 1), clonic GCS without tonic arm extension or flexion (type 2), and GCS with unilateral or asymmetric tonic arm extension or flexion (type 3). Association between PGES and person-specific or seizure-specific variables was analyzed after correction for individual effects and the varying number of seizures.

RESULTS

A total of 99 GCS in 69 patients were included. Occurrence of PGES was independently associated with GCS type (p < 0.001) and lack of early administration of oxygen (p < 0.001). Odds ratio (OR) for GCS type 1 in comparison with GCS type 2 was 66.0 (95% confidence interval [CI 5.4-801.6]). In GCS type 1, risk of PGES was significantly increased when the seizure occurred during sleep (OR 5.0, 95% CI 1.2-20.9) and when oxygen was not administered early (OR 13.4, 95% CI 3.2-55.9).

CONCLUSION

The risk of PGES dramatically varied as a function of GCS semiologic characteristics. Whatever the type of GCS, occurrence of PGES was prevented by early administration of oxygen.

Neuroimaging observations linking neurocysticercosis and mesial temporal lobe epilepsy with hippocampal sclerosis

OBJECTIVE

To test if chronic calcificed neurocysticercosis (cNCC) and hippocampal sclerosis occur more often than by chance ipsilateral to the same brain hemisphere or brain region in mesial temporal lobe epilepsy associated with hippocampal sclerosis (MTLE-HS) plus neurocysticercosis. This proof-of-concept would provide important evidence of a direct pathogenic relationship between neurocysticercosis and MTLE-HS.

METHODS

A cohort of 290 consecutive MTLE-HS surgical patients was studied. A test of proportions was used to analyze if the proportion of patients with a single cNCC lesion matching the same brain hemisphere or region of hippocampal sclerosis was significantly greater than 50%, as expected by the chance.

RESULTS

Neuroimaging findings of cNCC were observed in 112 (38.6%) of 290 MTLE-HS patients and a single cNCC lesion occurred in 58 (51.8%) of them. There were no differences in main basal clinical characteristics of MTLE-HS patients with single or multiple cNCC lesions. In patients with single cNCC lesions, the lesion matched the side in which hippocampal sclerosis was observed in 43 (74.1%) patients, a proportion significantly greater than that expected to occur by chance (p=0.008). Neurocysticercosis in temporal lobe was ipsilateral to hippocampal sclerosis in 85.0% of patients and accounted mostly for this result.

CONCLUSIONS

This work is a proof-of-concept that the association of neurocysticercosis and MTLE-HS cannot be explained exclusively by patients sharing common biological or socio-economic predisposing variables. Instead, our results suggest the involvement of more direct pathogenic mechanisms like regional inflammation, repetitive seizures or both. Neurocysticercosis within temporal lobes was particularly related with ipsilateral hippocampal sclerosis in MTLE-HS, a finding adding new contributions for understanding MTLE-HS plus cNCC or perhaps to other forms of dual pathology in MTLE-HS.

The social context and the need of information from patients with epilepsy: evaluating a tertiary referral service

Objective Characterize the social profile and the need of information from patients with refractory epilepsy. Method A semi-structured questionnaire was applied to 103 patients to investigate sociodemographic aspects, pharmacotherapy and any doubts about epilepsy. Results Patients were highly dependent on having a free and accessible supply of antiepileptic drugs. Sixty-eight percent of the population was unemployed, and 26% confirmed receiving social security benefits due to epilepsy. Twenty-nine percent of the population reached high school. Eighty-five percent of the patients had at least one doubt about epilepsy; treatment and epilepsy aspects in general were the main topics. Conclusion : As observed in developed countries, patients with refractory epilepsy from a developing country also have high rates of unemployment and low educational levels. The results raise a concern about the need of information about epilepsy by patients and their families, urging the necessity to invest in strategies to solve this deficiency in knowledge.

Drug utilization profile in adult patients with refractory epilepsy at a tertiary referral center

Objective To evaluate the utilization profile of antiepileptic drugs in a population of adult patients with refractory epilepsy attending a tertiary center. Method Descriptive analyses of data were obtained from the medical records of 112 patients. Other clinical and demographic characteristics were also registered. Results Polytherapies with ≥3 antiepileptic drugs were prescribed to 60.7% of patients. Of the old agents, carbamazepine and clobazam were the most commonly prescribed (72.3% and 58.9% of the patients, respectively). Among the new agents, lamotrigine was the most commonly prescribed (36.6% of the patients). At least one old agent was identified in 103 out of the 104 polytherapies, while at least one new agent was prescribed to 70.5% of the population. The most prevalent combination was carbamazepine + clobazam + lamotrigine. The mean AED load found was 3.3 (range 0.4–7.7). Conclusion The pattern of use of individual drugs, although consistent with current treatment guidelines, is strongly influenced by the public health system.

Cognitive and surgical outcome in mesial temporal lobe epilepsy associated with hippocampal sclerosis plus neurocysticercosis: a cohort study

Background

Where neurocysticercosis (NCC) is endemic, chronic calcified neurocysticercosis (cNCC) can be observed in patients with mesial temporal lobe epilepsy associated with hippocampal sclerosis (MTLE-HS). Considering that both disorders cause recurrent seizures or cognitive impairment, we evaluated if temporal lobectomy is cognitively safe and effective for seizure control in MTLE-HS plus cNCC.

Methods

Retrospective cohort study of neuropsychological profile and surgical outcome of 324 MTLE-HS patients submitted to temporal lobectomy, comparing the results according to the presence or absence of cNCC.

Findings

cNCC occurred in 126 (38.9%) of our MTLE-HS patients, a frequency higher than expected, more frequently in women than in men (O.R. = 1.66; 95% C.I. = 1.05–2.61; p = 0.03). Left-side (but not right side) surgery caused impairment in selected neuropsychological tests, but this impairment was not accentuated by the presence of cNCC. Ninety-four (74.6%) patients with MTLE-HS plus cNCC and 153 patients (77.3%) with MTLE-HS alone were Engel class I after surgery (O.R. = 1.16; 95% C.I. = 0.69–1.95; p = 0.58). However, the chances of Engel class IA were significantly lower in MTLE-HS plus cNCC than in patients with MTLE-HS alone (31.7% versus 48.5%; O.R. = 2.02; 95% C.I. = 1.27–3.23; p = 0.003). Patients with MTLE-HS plus cNCC showed higher rates of Engel class ID (15.1% versus 6.6%; O.R. = 2.50; 95% C.I. = 1.20–5.32; p = 0.012).

Interpretation

cNCC can be highly prevalent among MTLE-HS patients living in areas where neurocysticercosis is endemic, suggesting a cause-effect relationship between the two diseases. cNCC does not add further risk for cognitive decline after surgery in MTLE-HS patients. The rates of Engel class I outcome were very similar for the two groups; however, MTLE-HS plus cNCC patients achieved Engel IA status less frequently, and Engel ID status more frequently. Temporal lobectomy can be safely performed in most patients with MTLE-HS plus cNCC without affecting cognitive outcome. Long-term surgical seizure control in MTLE-HS plus cNCC is still satisfactory, as long as selected patients remain under medication.

[Interchangeability among therapeutics equivalents of lamotrigine in the treatment of refractory epilepsy patients: risks and benefits]

INTRODUCTION

Epilepsy is a condition characterized by signs and symptoms of neurological disorder. Lamotrigine has been widely used, mainly due to their greater tolerability and lower rate of drug interactions with other antiepileptic drugs however the newest antiepileptic drugs have high cost to patient. In Brazil there are three different sort of pharmaceutical equivalents (reference, generic and similar), and the Brazilian health care authorities offers to users the possibility to receive them free of charge. Moreover these pharmaceutical equivalents can change during the treatment of epilepsy because this authorities buy the cheapest by public tender two or three times a year.

AIM

To evaluate the clinical and laboratory findings related to the most frequently used therapeutic equivalents of lamotrigine (reference drugs and similar products).

PATIENTS AND METHODS

Two similar formulations (A and B) and one reference (C) were tested in nine epileptic refractory patients. The study was divided into three periods of 42 days, one for each formulation, and medical data about the frequency of seizures, the occurrence of side effects and measurement of plasma concentrations of lamotrigine were collected.

RESULTS

The average number of seizures/week and plasma concentration of lamotrigine for formulations A, B and C were not statistically significant differences. Three patients during the use of the formulation C presented mild and transitory side effects.

CONCLUSION

Similar or reference drugs showed satisfactory results, however the interchangeability among the formulations raise the difficulty for the management of seizures in refractory epilepsy.

Do psychiatric comorbidities predict postoperative seizure outcome in temporal lobe epilepsy surgery?

Clinical and demographic presurgical variables may be associated with unfavorable postsurgical neurological outcome in patients with mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS). However, few reports include preoperative psychiatric disorders as a factor predictive of long-term postsurgical MTLE-HS neurological outcome. We used Engel's criteria to follow 186 postsurgical patients with MTLE-HS for an average of 6 years. DSM-IV criteria and psychiatric comorbidity criteria specific to epilepsy (interictal dysphoric disorder, postictal and interictal psychosis) were used to assess presurgical psychiatric disorders. Kaplan-Meier event-free survival and adjusted hazard ratios were estimated with unconditional logistic regression. Seventy-seven (41.4%) patients had a preoperative Axis I psychiatric diagnosis. Thirty-six patients had depression, 11 interictal dysphoric disorder, 14 interictal psychosis, 6 postictal psychosis, and 10 anxiety disorders. Twenty-three (12.4%) patients had Axis II personality disorders. Regarding seizure outcome, preoperative anxiety disorders (P=0.009) and personality disorders (P=0.003) were positively correlated with Engel class 1B (remaining auras) or higher. These findings emphasize the importance of presurgical psychiatric evaluation, counseling, and postsurgical follow-up of patients with epilepsy and psychiatric disorders.

Outcome of hemispheric surgeries for refractory epilepsy in pediatric patients

BACKGROUND

Hemispheric brain lesions are commonly associated with early onset of catastrophic epilepsies and multiple seizure types. Hemispheric surgery is indicated for patients with unilateral intractable epilepsy. Although described more than 50 years ago, several new techniques for hemispherectomy have only recently been proposed aiming to reduce operatory risks and morbidity.

MATERIALS AND METHODS

We present the clinical characteristics, presurgical workup, and postoperative outcome of a series of pediatric patients who underwent hemispherectomy for medically intractable epileptic seizures. Thirty-nine patients with medically intractable epilepsy underwent surgery from 1996 to 2005.

RESULTS AND DISCUSSION

We analyzed demographic data, interictal and ictal EEG findings, age at surgery, surgical technique and complications, and postsurgical seizure outcome. There were 74.4% males. Tonic and focal motor seizures occurred in 30.8 and 20.5% of the patients. Most frequent etiologies were Rasmussen encephalitis (30.8%) and malformation of cortical development (23.1%). Postsurgical outcomes were Engel classes I and II for 61.5% of the patients. In general, 89.5% of the patients exhibited at least a 90% reduction in seizure frequency. All patients had acute worsening of hemiparesis after surgery. Basically, two surgical techniques have been employed, both with similar results, although a trend has been noted toward one of the procedures which produced consistently complete disconnection. Patients with hemispheric brain lesions usually have abnormal neurological development and intractable epilepsy. When video-EEG monitoring and magnetic resonance imaging show unilateral disease, the patient may evolve with a good surgical outcome. We showed that a marked reduction in seizure frequency may be achieved, with acceptable neurological impairments.

Foramen Ovale Electrodes Can Identify a Focal Seizure Onset When Surface EEG Fails in Mesial Temporal Lobe Epilepsy

PURPOSE

We analyze a series of patients with mesial temporal lobe epilepsy (MTLE) associated with hippocampal sclerosis (HS) submitted to presurgical investigation with scalp sphenoidal, followed by foramen ovale electrodes (FO), and, when necessary, with depth temporal electrodes. We sought to evaluate the clinical utility of FO in patients with MTLE-HS.

METHODS

We included patients who had phase I investigation with bitemporal independent seizures, nonlateralized ictal onsets, or ictal onset initiating in the side contralateral to the side of hippocampal sclerosis. Patients whose implanted FO failed to demonstrate an unambiguous unilateral ictal onset were later evaluated with depth hippocampal electrodes.

RESULTS

Between May 1994 and December 2004, 64 patients met our inclusion criteria: 33 female (51.5%) and 31 male subjects (48.5%). The mean age at enrollment was 37.66+/-10.6 years (range, 12-56 years). The groups with nonlateralized surface ictal EEG onsets and contralateral EEG onsets had a greater chance of lateralization with FO when compared with the group with bilateral independent seizures on surface EEG (p<0.01). Foramen ovale electrodes lateralized the seizures in 60% of patients. Seventy percent of patients became seizure free after temporal lobectomy. Five patients were implanted with depth temporal electrodes after FO video-EEG monitoring. The depth-electrode EEG onsets confirmed the results of FO video-EEG monitoring in all patients, and the surgery was refused.

CONCLUSIONS

In MTLE-HS, FO is a reliable method for lateralization of seizures that are not clearly recorded by surface EEGs.

Volumetric Evidence of Bilateral Damage in Unilateral Mesial Temporal Lobe Epilepsy

PURPOSE

We sought to analyze the contralateral volumes of the temporal pole, posterior segment of the temporal lobe, amygdala, hippocampus, and parahippocampal gyrus in patients with temporal lobe epilepsy (TLE) due to histologically proven mesial temporal lobe sclerosis (MTLS), seizure free for >or=4 years of postsurgical follow-up.

METHODS

Forty-six (23 male) TLE patients, operated on between 1996 and 2001, with histopathologic diagnosis of MTLS, and a postsurgical follow-up of >or=4 years, had their temporal lobe structures manually segmented, measured, and compared with those of 23 normal volunteers, paired as groups for sex, age, and handedness.

RESULTS

The mean volumes of the contralateral temporal pole, hippocampus, and parahippocampal gyrus in TLE patients were significantly lower than those in controls.

CONCLUSIONS

MRI volumetric data show that the damage in TLE due to MTS may be more widespread and bilateral, even in patients with unilateral TLE by clinical and neurophysiological criteria. Our results are relevant to the discussion of epileptogenic mechanisms in TLE.

Seizure outcome after surgery for epilepsy due to focal cortical dysplastic lesions

Neocortical development is a highly complex process encompassing cellular proliferation, neuronal migration and cortical organization. At any time this process can be interrupted or modified by genetic or acquired factors causing malformations of cortical development (MCD). Epileptic seizures are the most common type of clinical manifestation, besides developmental delay and focal neurological deficits. Seizures due to MCD are frequently pharmacoresistant, especially those associated to focal cortical dysplasia (FCD). Surgical therapy results have been reported since 1971, however, currently available data from surgical series are still limited, mainly due to small number of patients, distinct selection of candidates and surgical strategies, variable pathological diagnosis and inadequate follow-up. This study addresses the possibilities of seizure relief following resection of focal cortical dysplasia, and the impact of presurgical evaluation, extent of resection and pathological findings on surgical outcome. We included 41 patients, 22 adults and 19 children and adolescents, with medically intractable seizures operated on from 1996 to 2002. All were submitted to standardized presurgical evaluation including high-resolution MRI, Video-EEG monitoring and ictal SPECT. Post-surgical seizure outcome was classified according to Engel's schema. Univariate and multivariate analysis were performed. Fifteen patients had temporal and 26 extratemporal epilepsies. Of the total 26 patients (63.4%) reached seizure-free status post-operatively. There was no correlation between outcome and age at surgery, duration of epilepsy, frequency of seizures, and pathological findings. There was, however, a clear correlation with topography of FCD (temporal versus extratemporal) and regional ictal EEG onset, on univariate as well as multivariate analysis.

Cognitive performance of patients with mesial temporal lobe epilepsy is not associated with human prion protein gene variant allele at codons 129 and 171

Cognitive impairment has long been recognized in people with medically refractory epilepsies. Mesial temporal lobe epilepsy related to hippocampal sclerosis (MTLE-HS), the most common surgically remediable epileptic syndrome, has been associated with a cellular prion protein (PrPc) gene (Prnp) variant allele at codon 171. The polymorphism consisting of a methionine-for-valine substitution at codon 129 has been associated with early cognitive deterioration in elderly people and patients with Down syndrome. The same variant allele in homozygosis (V129V) has been associated to a lower long-term memory in healthy humans. PrPc mediates several processes related to neuroplasticity, and its role in cognitive processes remains unknown. In this study, we evaluated the genetic contribution of Prnp alleles to cognitive performance in patients with MTLE-HS. Cognitive performance, measured with 19 neuropsychological tests, of patients with refractory MTLE-HS with the normal Prnp genotypes was compared with that of patients with the variant alleles at codons 129 and 171. With the effects of clinical, demographic, electrophysiological, and neuroimaging variable interactions controlled by multiple linear regression analysis and adjustment for multiple test comparisons, the presence of Prnp variant alleles was found not to be significantly associated to cognitive performance of patients with MTLE-HS. The presence of variant alleles at codons 129 and 171 is not associated to cognitive performance of patients with refractory MTLE-HS.

Calcified cysticercotic lesions and intractable epilepsy: a cross sectional study of 512 patients

BACKGROUND

Neurocysticercosis is a major cause of epilepsy in developing countries and is endemic in Brazil. To test the hypothesis that the aetiological profile of patients with intractable epilepsy in Brazil includes neurocysticercosis, we conducted a cross sectional study investigating the aetiology of intractable epilepsy.

METHODS

A total of 512 patients evaluated at the outpatient clinic for intractable epilepsy at the Ribeirão Preto School of Medicine were included in the survey. Medical intractability was determined on the basis of seizure incidence and severity, and response to appropriate epilepsy management. Neuroimaging included brain CT with non-contrasted and contrasted phases and high resolution MRI. Patients were divided into neurocysticercosis and non-neurocysticercosis groups according to previous diagnostic criteria.

RESULTS

The most common epileptogenic lesions were mesial temporal sclerosis (MTS; 56.0%), malformations of cortical development (12.1%), and brain tumours (9.9%). Neuroimaging was normal in 8.7% of patients. Calcifications were found in 27% of patients and were significantly more common in patients with MTS than in those without MTS (p<0.001). Isolated neurocysticercosis was found in only eight patients (1.56%).

CONCLUSIONS

These data suggest that neurocysticercosis is an uncommon cause of intractable epilepsy, even in an endemic region such as Brazil, and that it may only represent a coexistent pathology. However, an analysis of our findings reveals that neurocysticercosis was more common in patients with MTS. This finding could suggest either that there is a cause-effect relationship between MTS and neurocysticercosis, or that MTS and neurocysticercosis co-vary with a missing variable, such as socio-economic status.

Molecular characterisation of birch bark tar by headspace solid-phase microextraction gas chromatography–mass spectrometry: A new way for identifying archaeological glues

To develop an analytical methodology, as non-destructive as possible, suitable for the identification of natural substances from archaeological origin, we studied the potentiality of solid-phase microextraction (SPME) for analysing birch bark tar, an adhesive commonly used during ancient times. First of all, birch bark tars were produced by a controlled heating of birch bark. The two kinds of samples obtained using different processes of fabrication, one at liquid state, the second one at solid state, were then analysed by headspace HS-SPME-GC-MS. Different conditions of sample treatment were tested (two different fibre coatings, various times and temperatures of extraction) in order to suggest optimal conditions for the analysis of birch bark tar. Both samples were shown to be rich in volatile organic components. Two main groups of constituents, namely phenolic compounds issued from lignin or tannin known to be present in bark and sesquiterpenoid hydrocarbons, secondary metabolites largely distributed in the plant kingdom, were detected for the first time in birch bark tar. HS-SPME-GC-MS appears thus to be a very efficient method for investigating the volatiles emitted by plant tars and could be further used for the study of birch bark tar samples issued from archaeological context.

Clinical features of patients with posterior cortex epilepsies and predictors of surgical outcome

PURPOSE

Posterior cortex epilepsies (PCEs) encompass a group of epilepsies originating from the occipital, parietal, or occipital border of the temporal lobe, or from any combination of these regions. When their seizures are refractory to pharmacologic treatment, these patients are usually referred for surgery. The aim of our study was to analyze clinical characteristics of all PCE patients referred for surgery from 1994 to 2003, and to search for predictors of surgical outcome.

METHODS

We performed a retrospective analysis of clinical and laboratory data from 81 consecutive refractory PCE patients referred for surgery. Surgical and nonsurgical groups of patients were compared, and detailed analyses of all variables of the surgical cases were performed in the search for predictors of seizure outcome.

RESULTS

Risk factors for PCEs included gliosis (34.56%), malformations of cortical development (33.33%), tumors (8.64%), brain trauma (3.70%), Sturge-Weber disease (4.93%), vascular malformations (3.70%), family history of epilepsy (3.70%), history of CNS infections (2.46%), and low IQ (2.46%). Of the 81 patients, 44 were submitted to surgery at the time of the completion of this study. Surgical treatment was highly effective in improving seizures (p<0.001) when compared with previous pharmacologic treatment alone. Twenty-eight (65.11%) patients became seizure free after surgery versus none in the nonsurgical group. Regarding outcome predictors, patients with shorter duration of epilepsy and those without neurologic abnormalities on clinical examination had higher chances of favorable evolution.

CONCLUSIONS

Surgical treatment is effective for the treatment of PCEs and superior to pharmacologic therapy alone. In our series, shorter duration of epilepsy and normal neurologic examination were the only independent variables that predicted better surgical outcome.

Suppression of obsessive-compulsive symptoms after epilepsy surgery

We report two male patients with medically intractable epilepsy and obsessive-compulsive disorder (OCD) symptoms. Both patients experienced remission of obsessive-compulsive symptoms after surgical treatment of epilepsy. Although the surgeries targeted different brain regions, the two patients had in common unilateral anterior cingulate cortex ablation. On the basis of these observations, we discuss the pathophysiology of OCD symptoms, emphasizing the role of corticosubcortical pathways in their genesis. Our data suggest that surgeries that affect neural loops associated with obsessive-compulsive symptoms can lead to an improvement of OCD; however, the structures responsible for this effect cannot be conclusively determined.

Cognitive performance of patients with mesial temporal lobe epilepsy and incidental calcified neurocysticercosis

OBJECTIVES

Although chronic calcified neurocysticercosis (NCC) has been considered a major cause of symptomatic epilepsy in developing countries, it can also be an incidental pathological finding in epileptic patients from endemic regions. The mechanisms of brain plasticity occurring in patients with NCC during and after the inflammatory process related to the parasite infection, death, degeneration, and calcification within the host brain might be an independent factor for cognitive impairment in patients with NCC and epilepsy. In order to assess this possibility cognitive performance of patients with mesial temporal lobe epilepsy related to hippocampal sclerosis (MTLE-HS) with and without NCC was investigated through structured neuropsychological testing.

METHODS

Cognitive performance of long term MTLE-HS patients with (HS-NCC group, n = 32) and without NCC (HS only, n = 48) was compared. Imbalances between the two groups with respect to clinical, demographic, neuroimaging, and electrophysiological variables were adjusted by linear multiple regression analysis and Bonferroni correction for multiple tests.

RESULTS AND CONCLUSIONS

There were no cognitive performance differences between HS-NCC and HS only patients, leading to the conclusion that chronic calcified NCC per se does not aggravate the cognitive performance of patients with long term MTLE-HS.

Surgically amenable epilepsies in children and adolescents: clinical, imaging, electrophysiological, and post-surgical outcome data

BACKGROUND AND PURPOSE

A large number of patients with epilepsy in the pediatric population have medically intractable epilepsy. In this age group seizures are usually daily or weekly, and response to antiepileptic therapy is poor, especially for those with neurological abnormalities and symptomatic epilepsies. However, several authors have already demonstrated similarly favorable long-term post-surgical seizure control when comparing pediatric and adult populations. In this article we aim to report the experience of the Ribeirão Preto Epilepsy Surgery Program in pediatric epilepsy surgery.

PATIENTS AND METHODS

We analyzed 107 patients with medically intractable epilepsy operated on between July 1994 and December 2002, considering age at surgery, seizure type, pathological findings, and seizure outcome. All data were prospectively collected according to protocols previously approved by the institution ethics committee.

RESULTS

We analyzed a total of 115 operations performed in 107 patients. There was no difference in sex distribution. Complex partial seizures occurred in 31.4% of the patients, followed by tonic seizures (25.9%), focal motor seizures (15.4%), and infantile spasms (13.3%). The most common etiologies were cortical developmental abnormalities (25.2%), tumors (16.8%), mesial temporal sclerosis (15.9%), Rasmussen syndrome (6.5%), and tuberous sclerosis (6.5%). Overall post-surgical seizure outcome showed 67.2% of the patients within Engel classes I and II, reaching 75.0% when patients with callosotomies were excluded.

CONCLUSIONS

Post-surgical seizure control in the pediatric population is similar to that in adult patients, despite the fact that epilepsies in this age group are more frequently of extratemporal origin, suggesting that surgery should be considered in children as soon as intractability is determined.

Cortical malformations are associated with a rare polymorphism of cellular prion protein

Studies in animals lacking the cellular prion protein (PrP(c)) gene (Prnp) showed higher neuronal excitability in vitro and increased sensitivity to seizures in vivo. The authors previously reported a rare polymorphism at codon 171 (Asn-->Ser) of human Prnp to be associated with mesial temporal lobe epilepsy related to hippocampal sclerosis. They demonstrated that the same variant allele is also associated with symptomatic epilepsies related to different forms of malformations of cortical development.

Interictal SPECT in patients with mesial temporal lobe epilepsy and psychosis: a case-control study

Psychosis is commonly observed in patients with mesial temporal lobe epilepsy related to hippocampal sclerosis (MTLE-HS). Interictal single photon emission computed tomography (SPECT) was performed to compare regional cerebral blood flow (rCBF) pattern of MTLE-HS patients with psychosis of epilepsy (POE) comorbidity and MTLE-HS patients without any psychiatric disorders (Control group). For this, 21 patients with POE and 23 Control patients were matched by educational level, clinical, demographic, electrophysiological, and MRI data. SPECT scans were acquired using (99m)Tc and interpreted with a semiquantitative method. We analyzed brain regions of interest (ROI) of frontal, temporal, and parietal cortex, in addition to subcortical structures. There were no significant statistical differences of ROI between the POE group and the Control group after Bonferroni adjustment. However, we observed a trend for rCBF increase of right posterior cingulate in the POE Group. This increase would be in accordance with recent findings of cingulate abnormalities in schizophrenia, suggesting that abnormal function in this region might be associated with the psychotic phenomena.

Surgical treatment for mesial temporal lobe epilepsy in the presence of massive calcified neurocysticercosis

BACKGROUND

Neurocysticercosis (NCC) is the most common parasitic disease of the human central nervous system and a major health problem for most developing countries. The most common clinical manifestations of NCC are epileptic seizures. Whenever epilepsy and NCC coexist in the same patient, an uncertainty may rise about a causal relationship between them.

OBSERVATION

We described a female patient with disseminated calcified NCC lesions and intractable epilepsy. Her medical history included cysticercotic meningoencephalitis and status epilepticus caused by active NCC. Fundoscopy showed the ocular presence of parasite; computed tomography of the brain showed evidence of cystic lesions with the scolex and calcified lesions; enzyme-linked immunosorbent assay of the cerebrospinal fluid was positive for cysticercosis. Epileptic seizures started after an 8-year silent period. Magnetic resonance imaging showed left hippocampal sclerosis. Plain x-ray film showed calcifications in muscles and subcutaneous tissue. Video-electroencephalography and ictal and interictal single-photon emission computed tomography disclosed left mesial temporal lobe epilepsy. The patient underwent left temporal lobectomy and has been seizure free since surgery, for a follow-up of 4 years.

CONCLUSION

This case report highlights and supports surgical therapy in patients with epileptic seizures and calcified NCC, even when there are several calcifications, provided that clear localization of epilepsy has been determined by means of a presurgical workup.

Ictal chronology and interictal spikes predict perfusion patterns in temporal lobe epilepsy: a multivariate study

Typical (TPP) and atypical (APP) perfusion patterns (PP) may be seen in ictal SPECT of patients with temporal lobe epilepsy (TLE). APP may pose problem in the lateralization of the epileptogenic zone (EZ). We aimed to investigate predictive variables for the occurrence of TPP and APP. Fifty-one TLE patients were submitted to successful anterior-mesial temporal lobectomy. Univariate (UVA) and multivariate (MVA) analysis were performed upon clinical data, distribution of interictal spikes, and ictal chronology of seizures. From MVA, a final predictive model (FPM) was determined to better predict TPP and APP. Forty patients showed TPP (78.5%) and 11 patients APP (21.5%). Accuracy of ictal SPECT was higher in the unilateral (UIS) than in the bilateral (BIS) interictal spikes group (P = 0.05). FPM showed that patients exhibiting BIS, with shorter proportion of the electrographic seizure occurring after completion of tracer injection, and longer clinical than EEG seizure duration had more APP (P = 0.003). Generalized tonic-clonic seizures did not result in more APP. We concluded that analysis of ictal SPECT in TLE requires the knowledge of TPP and APP, the distribution of interictal spikes on temporal lobes and the ictal chronology of seizures. BIS showed that beyond a more complex epileptogenicity and seizure propagation, they may also lead to APP.

Surgical outcome in mesial temporal sclerosis correlates with prion protein gene variant

BACKGROUND

Mesial temporal lobe epilepsy related to hippocampal sclerosis (MTLE-HS) is the most common surgically remediable epileptic syndrome. Ablation of the cellular prion protein (PrP(c)) gene (PRNP) enhances neuronal excitability of the hippocampus in vitro and sensitivity to seizure in vivo, indicating that PrP(c) might be related to epilepsy.

OBJECTIVE

To evaluate the genetic contribution of PRNP to MTLE-HS.

METHODS

The PRNP coding sequence of DNA from peripheral blood cells of 100 consecutive patients with surgically treated MTLE-HS was compared to that from a group of healthy controls adjusted for sex, age, and ethnicity (n = 180). The presence of PRNP variant alleles was correlated with clinical and presurgical parameters as well as surgical outcome.

RESULTS

A variant allele at position 171 (Asn-->Ser), absent in controls, was found in heterozygosis (Asn171Ser) in 23% of patients (p < 0.0001). The PRNP genotypes were not correlated with any clinical or presurgical data investigated. However, patients carrying the Asn171Ser variant had a five times higher chance of continuing to have seizures after temporal lobectomy (95% CI 1.65 to 17.33, p = 0.005) than those carrying the normal allele. At 18 months after surgery, 91.8% of patients with the normal allele at codon 171 were seizure free, in comparison to 68.2% of those carrying Asn171Ser (p = 0.005).

CONCLUSIONS

The PRNP variant allele Asn171Ser is highly prevalent in patients with medically untreatable MTLE-HS and influences their surgical outcome. The results suggest that the PRNP variant allele at codon 171 (Asn171Ser) is associated with epileptogenesis in MTLE-HS.

[Pacemaker syndrome after dual-chamber implantation: consequence of a very long atrial activation delay]

Many circumstances, generally occurring in inappropriate device's adjustment or in specific myocardial conduction's disturbances, can result in dual chamber indications in pace maker syndromes. Our case report is about a man implanted with a dual chamber device with a dilated right atrium and intra atrial conduction delay resulting in a delayed post pacing atrial activation time. The consequence was an atrial contraction occurring during closed atrioventricular valves.

Accuracy of ictal SPECT in mesial temporal lobe epilepsy with bilateral interictal spikes

OBJECTIVE

In mesial temporal lobe epilepsy (MTLE), the rate of correct seizure lateralization of ictal semiology and ictal EEG is better for patients with unilateral interictal spikes (UIS) than for patients with bilateral interictal spikes (BIS), possibly due to rapid seizure propagation patterns associated with bilateral epileptogenesis. In this study, the authors investigated if ictal SPECT is a reliable diagnostic test for both UIS and BIS patients.

METHODS

Video-EEG recording was used as the gold standard to examine the accuracy of ictal SPECT and its relationship with interictal and ictal EEG. Ninety-three consecutive patients with MTLE associated with hippocampal sclerosis were included in the analysis. Ictal SPECT was considered accurate if two blinded observers independently lateralized the scan correctly.

RESULTS

Ictal SPECT correctly lateralized 75 (80.6%) of 93 scans. The rate of correct seizure lateralization was 87.6% for the UIS group and only 55.0% for the BIS group (p = 0.0027). In the EEG epochs, 66.7% of BIS patients vs 43.4% of UIS patients had nonlateralized ictal EEG (p < 0.001).

CONCLUSION

The authors conclude that the accuracy of ictal SPECT is worse for MTLE patients with BIS than for those with UIS. The role of ictal SPECT in presurgical evaluation of patients with BIS must be reviewed.

Effect of tiazofurin on tomato plants infected with tomato spotted wilt virus

Tiazofurin (2-beta-D-ribofuranosylthiazole-4-carboxamide) was examined for its activity against tomato-spotted wilt virus (TSWV) in tomato plants. Solutions containing 50, 100, 200, 400 and 800 mg/l of the drug were sprayed onto the leaves. The results showed that 100 and 200 mg/l were the most efficient concentrations to suppress TSWV infection, thereby delaying the appearance of systemic symptoms. The drug was more effective in controlling TSWV infection when applied after than before virus inoculation. The results suggest that tiazofurin can be used as an efficient antiviral drug in the treatment of TSWV-infected tomato plants.