Coffee and cigarette smoking interactions with lamotrigine

The objective of this analysis was to determine possible interactions between lamotrigine (LTG) and coffee or cigarette use. As part of the statistical analysis of factors influencing LTG pharmacokinetics (PK) in the Equigen chronic dose study, we collected prospective data from enrolled patients on their use of coffee and cigarettes. Subjects were part of a crossover replication study of generic LTG products with rigorous blood sampling and were instructed to not change their typical consumption of these products for the duration of the study. A total of 35 subjects were enrolled, with 33 subjects having sufficient data for analysis. Higher consumption of coffee was associated with a significantly lower area under the curve (AUC) and maximum concentration (Cmax) of lamotrigine (LTG). Higher cigarette use did not result in a significant change in AUC or Cmax. Coffee, but not cigarette use, either induces LTG metabolism or inhibits LTG absorption.

Nine-year prospective efficacy and safety of brain-responsive neurostimulation for focal epilepsy

OBJECTIVE

To prospectively evaluate safety and efficacy of brain-responsive neurostimulation in adults with medically intractable focal onset seizures (FOS) over 9 years.

METHODS

Adults treated with brain-responsive neurostimulation in 2-year feasibility or randomized controlled trials were enrolled in a long-term prospective open label trial (LTT) to assess safety, efficacy, and quality of life (QOL) over an additional 7 years. Safety was assessed as adverse events (AEs), efficacy as median percent change in seizure frequency and responder rate, and QOL with the Quality of Life in Epilepsy (QOLIE-89) inventory.

RESULTS

Of 256 patients treated in the initial trials, 230 participated in the LTT. At 9 years, the median percent reduction in seizure frequency was 75% (p < 0.0001, Wilcoxon signed rank), responder rate was 73%, and 35% had a ≥90% reduction in seizure frequency. We found that 18.4% (47 of 256) experienced ≥1 year of seizure freedom, with 62% (29 of 47) seizure-free at the last follow-up and an average seizure-free period of 3.2 years (range 1.04-9.6 years). Overall QOL and epilepsy-targeted and cognitive domains of QOLIE-89 remained significantly improved (p < 0.05). There were no serious AEs related to stimulation, and the sudden unexplained death in epilepsy (SUDEP) rate was significantly lower than predefined comparators (p < 0.05, 1-tailed χ2).

CONCLUSIONS

Adjunctive brain-responsive neurostimulation provides significant and sustained reductions in the frequency of FOS with improved QOL. Stimulation was well tolerated; implantation-related AEs were typical of other neurostimulation devices; and SUDEP rates were low.

CLINICALTRIALSGOV IDENTIFIER

NCT00572195.

CLASSIFICATION OF EVIDENCE

This study provides Class IV evidence that brain-responsive neurostimulation significantly reduces focal seizures with acceptable safety over 9 years.

Qualitative analysis of double inversion recovery MRI in drug-resistant epilepsy

PURPOSE

To determine whether Double Inversion Recovery (DIR) on 3T MRI can enhance detection of epileptogenic lesions Methods: 29 adult patients with DRE were enrolled in a prospective pilot study. Brain MRIs were obtained using a specialized protocol that included: (1) Fast-Spin EchoT2, (2) T2 fluid attenuated inversion recovery (FLAIR), and (3) DIR sequences. Two neuroradiologists blinded to clinical information independently reviewed each sequence in the order listed above for T2-hyperintense lesions. Cortical lesions were determined to be concordant with the epileptic focus based upon available clinical and electrodiagnostic testing.

RESULTS

Of 29 studies, 21 had a lesion identified with 13/21 abnormalities being non-specific. Of 8 remaining studies, 3 revealed a lesion only with DIR sequencing. DIR-lesions were concordant with clinical data in 1 subject, non-discordant in 1 subject, and discordant in 1 subject.

SIGNIFICANCE

DIR has the potential to be more sensitive in detecting cortically based lesions relative to standard imaging. More data are needed to assess the sensitivity and specificity of DIR, particularly as it pertains to identification of epileptogenic lesions using electrodiagnostic testing and outcome after surgery.

Parkinsonism Treatment: Part III—Update

OBJECTIVE:

The purpose of this review is to update clinicians with recent advances in the management of parkinsonism, including drug therapy, transplantation, and diet.

DATA SOURCES:

Pertinent articles were obtained from an English-language literature search using MEDLINE (1970–1991), Index Medicus (1987–1991), Current Contents (1990), and bibliographic reviews of review articles. Index terms included parkinsonism, selegiline, pergolide, vitamin E, and transplantation. Fifty-five articles (representing 85 percent of the complete literature search) were selected by multiple reviewers for their contribution to the stated purpose. Emphasis was placed on double-blind, placebo-controlled, and randomized studies. Data from cited articles were examined by multiple reviewers for support of their stated hypothesis and were included as background for justification of major points in this article; critical studies were abstracted in more detail.

RESULTS:

New therapeutic measures have been added to the treatment of parkinsonism. Selegiline, a monoamine oxidase inhibitor type B, has shown beneficial results, especially in early stages. Pergolide, a dopamine agonist, may be an efficacious alternative to bromocriptine resistance or intolerable adverse effects. Vitamin E may have protective antioxidant properties, but very few clinical data are available. Fetal tissue transplantation needs continued research and remains very controversial. Diet modification may maximize the results of therapy with exogenous dopamine therapy.

CONCLUSIONS:

Clinicians should familiarize themselves with new alternatives for the management of parkinsonism in order to be reliable consultants for both professional and lay persons.

Lateralization of mesial temporal lobe epilepsy with chronic ambulatory electrocorticography

OBJECTIVE

Patients with suspected mesial temporal lobe (MTL) epilepsy typically undergo inpatient video-electroencephalography (EEG) monitoring with scalp and/or intracranial electrodes for 1 to 2 weeks to localize and lateralize the seizure focus or foci. Chronic ambulatory electrocorticography (ECoG) in patients with MTL epilepsy may provide additional information about seizure lateralization. This analysis describes data obtained from chronic ambulatory ECoG in patients with suspected bilateral MTL epilepsy in order to assess the time required to determine the seizure lateralization and whether this information could influence treatment decisions.

METHODS

Ambulatory ECoG was reviewed in patients with suspected bilateral MTL epilepsy who were among a larger cohort with intractable epilepsy participating in a randomized controlled trial of responsive neurostimulation. Subjects were implanted with bilateral MTL leads and a cranially implanted neurostimulator programmed to detect abnormal interictal and ictal ECoG activity. ECoG data stored by the neurostimulator were reviewed to determine the lateralization of electrographic seizures and the interval of time until independent bilateral MTL electrographic seizures were recorded.

RESULTS

Eighty-two subjects were implanted with bilateral MTL leads and followed for 4.7 years on average (median 4.9 years). Independent bilateral MTL electrographic seizures were recorded in 84%. The average time to record bilateral electrographic seizures in the ambulatory setting was 41.6 days (median 13 days, range 0-376 days). Sixteen percent had only unilateral electrographic seizures after an average of 4.6 years of recording.

SIGNIFICANCE

About one third of the subjects implanted with bilateral MTL electrodes required >1 month of chronic ambulatory ECoG before the first contralateral MTL electrographic seizure was recorded. Some patients with suspected bilateral MTL seizures had only unilateral electrographic seizures. Chronic ambulatory ECoG in patients with suspected bilateral MTL seizures provides data in a naturalistic setting, may complement data from inpatient video-EEG monitoring, and can contribute to treatment decisions.

Lesions from patients with sporadic cerebral cavernous malformations harbor somatic mutations in the CCM genes: evidence for a common biochemical pathway for CCM pathogenesis

Cerebral cavernous malformations (CCMs) are vascular lesions affecting the central nervous system. CCM occurs either sporadically or in an inherited, autosomal dominant manner. Constitutional (germline) mutations in any of three genes, KRIT1, CCM2 and PDCD10, can cause the inherited form. Analysis of CCM lesions from inherited cases revealed biallelic somatic mutations, indicating that CCM follows a Knudsonian two-hit mutation mechanism. It is still unknown, however, if the sporadic cases of CCM also follow this genetic mechanism. We extracted DNA from 11 surgically excised lesions from sporadic CCM patients, and sequenced the three CCM genes in each specimen using a next-generation sequencing approach. Four sporadic CCM lesion samples (36%) were found to contain novel somatic mutations. Three of the lesions contained a single somatic mutation, and one lesion contained two biallelic somatic mutations. Herein, we also describe evidence of somatic mosaicism in a patient presenting with over 130 CCM lesions localized to one hemisphere of the brain. Finally, in a lesion regrowth sample, we found that the regrown CCM lesion contained the same somatic mutation as the original lesion. Together, these data bolster the idea that all forms of CCM have a genetic underpinning of the two-hit mutation mechanism in the known CCM genes. Recent studies have found aberrant Rho kinase activation in inherited CCM pathogenesis, and we present evidence that this pathway is activated in sporadic CCM patients. These results suggest that all CCM patients, including those with the more common sporadic form, are potentially amenable to the same therapy.

Benign MRI findings and their pathologic mimics

Otherwise benign MRI findings (so-called "incidentalomas") are a frequent cause of worry on the part of both clinician and patient. Knowledge of the imaging characteristics of incidentalomas, their (typically slight) pathologic significance, and how to distinguish these from less benign pathologic mimics can help avoid unnecessary worry, expense, and workup.

IGF-1 partially restores chemotherapy-induced reductions in neural cell proliferation in adult C57BL/6 mice

Chemotherapeutic agents produce persistent difficulties in memory through an unknown mechanism. We tested the hypothesis that chemotherapeutic agents readily able to cross the blood-brain barrier (cyclophosphamide and fluorouracil), as opposed to those not known to readily cross the barrier (paclitaxel and doxorubicin), reduce neural cell proliferation following chemotherapy. We found that 5-bromo-2-deoxyuridine labeling following chemotherapy given to C57BL/6 mice revealed a similar reduction in neural cell proliferation in the dentate gyrus for all four agents. Insulin-like growth factor 1, a molecule implicated in promoting neurogenesis, counteracted the effects of high doses of chemotherapy on neural cell proliferation.

Recent insights into cerebral cavernous malformations: animal models of CCM and the human phenotype

Cerebral cavernous malformations are common vascular lesions of the central nervous system that predispose to seizures, focal neurologic deficits and potentially fatal hemorrhagic stroke. Human genetic studies have identified three genes associated with the disease and biochemical studies of these proteins have identified interaction partners and possible signaling pathways. A variety of animal models of CCM have been described to help translate the cellular and biochemical insights into a better understanding of disease mechanism. In this minireview, we discuss the contributions of animal models to our growing understanding of the biology of cavernous malformations, including the elucidation of the cellular context of CCM protein actions and the in vivo confirmation of abnormal endothelial cell-cell interactions. Challenges and progress towards developing a faithful model of CCM biology are reviewed.

Generic substitution in the treatment of epilepsy: patient and physician perceptions

Generic substitution of branded antiepileptic drugs (AEDs) has sparked recent debates. We sought to understand perceptions about generic AED substitution and how these guide prescribing. Surveys were conducted among 550 adult patients with self-reported epilepsy and 606 physicians who treat patients with epilepsy. Physicians (88%) were concerned about an increase in breakthrough seizures in patients switched from a brand AED to a generic or among generics. Two-thirds of physicians and 34% of patients have linked breakthrough seizures to generic AED substitution. Physicians (75%) and patients (65%) were also concerned about efficacy. About half of physicians were extremely/very likely to request that brand AEDs not be substituted with a generic. In conclusion, perceptions among physicians and patients do not align with the FDA position that generic AEDs have the same clinical effect and safety profile as branded AEDs. Additional investigation on bioequivalence may help address ongoing concerns and inform policy-making decisions.

Hemorrhage from cavernous malformations of the brain: definition and reporting standards. Angioma Alliance Scientific Advisory Board

BACKGROUND AND PURPOSE

Cavernous malformations of the brain (CMs) cause intracranial hemorrhage, but its reported frequency varies, partly attributable to study design. To improve the validity of future research, we aimed to develop a robust definition of CM hemorrhage.

METHODS

We systematically reviewed the published literature (Ovid Medline and Embase to June 1, 2007) for definitions of CM hemorrhage used in studies of the untreated clinical course of >or=20 participants with CM(s), to inform the development of a consensus statement on the clinical and imaging features of CM hemorrhage at a scientific workshop of the Angioma Alliance.

RESULTS

A systematic review of 1426 publications about CMs in humans, revealed 15 studies meeting our inclusion criteria. Although 14 (93%) studies provided a definition of CM hemorrhage, data were less complete on the confirmatory type(s) of imaging (87%), whether CM hemorrhage should be clinically symptomatic (73%), and whether hemorrhage had to extend outside the CM or not (47%). We define a CM hemorrhage as requiring acute or subacute onset symptoms (any of: headache, epileptic seizure, impaired consciousness, or new/worsened focal neurological deficit referable to the anatomic location of the CM) accompanied by radiological, pathological, surgical, or rarely only cerebrospinal fluid evidence of recent extra- or intralesional hemorrhage. The definition includes neither an increase in CM diameter without other evidence of recent hemorrhage, nor the existence of a hemosiderin halo.

CONCLUSIONS

A consistent approach to clinical and brain imaging classification of CM hemorrhage will improve the external validity of future CM research.

Deletions in CCM2 are a common cause of cerebral cavernous malformations

Cerebral cavernous malformations (CCMs) are vascular abnormalities of the brain that can result in a variety of neurological disabilities, including hemorrhagic stroke and seizures. Mutations in the gene KRIT1 are responsible for CCM1, mutations in the gene MGC4607 are responsible for CCM2, and mutations in the gene PDCD10 are responsible for CCM3. DNA sequence analysis of the known CCM genes in a cohort of 63 CCM-affected families showed that a high proportion (40%) of these lacked any identifiable mutation. We used multiplex ligation-dependent probe analysis to screen 25 CCM1, -2, and -3 mutation-negative probands for potential deletions or duplications within all three CCM genes. We identified a total of 15 deletions: 1 in the CCM1 gene, 0 in the CCM3 gene, and 14 in the CCM2 gene. In our cohort, mutation screening that included sequence and deletion analyses gave disease-gene frequencies of 40% for CCM1, 38% for CCM2, 6% for CCM3, and 16% with no mutation detected. These data indicate that the prevalence of CCM2 is much higher than previously predicted, nearly equal to CCM1, and that large genomic deletions in the CCM2 gene represent a major component of this disease. A common 77.6-kb deletion spanning CCM2 exons 2-10 was identified, which is present in 13% of our entire CCM cohort. Eight probands exhibit an apparently identical recombination event in the CCM2 gene, involving an AluSx in intron 1 and an AluSg distal to exon 10. Haplotype analysis revealed that this CCM2 deletion occurred independently at least twice in our families. We hypothesize that these deletions occur in a hypermutable region because of surrounding repetitive sequence elements that may catalyze the formation of intragenic deletions.

Low frequency of PDCD10 mutations in a panel of CCM3 probands: potential for a fourth CCM locus

Cerebral cavernous malformations (CCMs) are vascular abnormalities of the brain that can result in a variety of neurological disabilities, including stroke and seizures. Linkage analyses using autosomal dominant families manifesting CCMs have identified three different causative loci on chromosomes 7q21.2 (CCM1), 7p13 (CCM2), and 3q25.2-q27 (CCM3). Mutations in the gene Krit1 are responsible for CCM1, mutations in the gene MGC4607 are responsible for CCM2, and mutations in the gene PDCD10 were recently reported to be responsible for CCM3. We report here that sequence analysis of PDCD10 in a panel of 29 probands lacking Krit1 and MGC4607 mutations revealed only three mutations. The frequency of identified mutations in the PDCD10 gene was surprisingly low, especially given that this panel was heavily biased towards non-CCM1, non-CCM2 probands. These data are in stark contrast with the linkage data, which suggests that 40% of inherited cases would be due to mutations in this gene. Interestingly, when examining the haplotypes of previously published CCM3 families, we found a distinct recombination event in one of the largest CCM3 families that excludes the PDCD10 gene. Although there are many potential explanations for this observation, when combined with the apparent under-representation of causative CCM mutations in PDCD10, this recombination event in a CCM3-linked family suggests that there may be an additional CCM gene in the same chromosomal region.

Mutations in a gene encoding a novel protein containing a phosphotyrosine-binding domain cause type 2 cerebral cavernous malformations

Cerebral cavernous malformations (CCMs) are congenital vascular anomalies of the central nervous system that can result in hemorrhagic stroke, seizures, recurrent headaches, and focal neurologic deficits. Mutations in the gene KRIT1 are responsible for type 1 CCM (CCM1). We report that a novel gene, MGC4607, exhibits eight different mutations in nine families with type 2 CCM (CCM2). MGC4607, similar to the KRIT1 binding partner ICAP1alpha, encodes a protein with a phosphotyrosine-binding domain. This protein may be part of the complex pathway of integrin signaling that, when perturbed, causes abnormal vascular morphogenesis in the brain, leading to CCM formation.

Mutational analysis of 206 families with cavernous malformations

OBJECT

A gene contributing to the autosomal-dominant cerebral cavernous malformation (CCM) phenotype, KRIT1 (an acronym for Krev Interaction Trapped 1), has been identified through linkage analysis and mutation screening. The authors collected blood samples from 68 patients with familial CCM and 138 patients with apparently sporadic CCM as well as from their families, in an effort to characterize the prevalence and spectrum of disease-causing sequence variants in the KRIT1 gene.

METHODS

The authors used single-strand conformational polymorphism analysis to identify genomic variants in KRIT1, which were sequenced to determine the specific mutation. Among 43 Hispanic-American kindreds who immigrated to the southwestern US from northern Mexico, 31 share an identical founder mutation. This Q455X mutation is found in 18 (86%) of 21 persons with a positive family history and in 13 (59%) of 22 persons with apparently sporadic CCM. This mutation was not found among 13 persons with CCM who were recruited from Mexico. These findings establish the key role of a recent founder mutation in Hispanic persons with CCM who live in the US. Although nearly all Hispanic families in the US in which there are multiple CCM cases linked to the CCM1 locus, only 13 of 25 non-Hispanic CCM-carrying families have displayed evidence of linkage to the CCM1 locus. Among these 13 families, the authors identified eight independent mutations in nine kindreds. They identified four additional mutations among 22 familial CCM kindreds with no linkage information, bringing the total number of independent mutations to 12. Inherited KRIT1 mutations were not detected among 103 non-Hispanic persons in whom a family history of CCM was rigorously excluded.

CONCLUSIONS

All mutations were nonsense mutations, frame-shift mutations predicting premature termination, or splice-site mutations located throughout the KRIT1 gene, suggesting that these are genetic loss-of-function mutations. These genetic findings, in conjunction with the clinical phenotype, are consistent with a two-hit model for the occurrence of CCM.

Accuracy and reproducibility of manual and semiautomated quantification of MS lesions by MRI

PURPOSE

To evaluate the accuracy, reproducibility, and speed of two semiautomated methods for quantifying total white matter lesion burden in multiple sclerosis (MS) patients with respect to manual tracing and to other methods presented in recent literature.

MATERIALS AND METHODS

Two methods involving the use of MRI for semiautomated quantification of total lesion burden in MS patients were examined. The first method, geometrically constrained region growth (GEORG), requires user specification of lesion location. The second technique, directed multispectral segmentation (DMSS), requires only the location of a single exemplar lesion. Test data sets included both clinical MS data and MS brain phantoms.

RESULTS

The mean processing times were 60 minutes for manual tracing, 10 minutes for region growth, and 3 minutes for directed segmentation. Intra- and interoperator coefficients of variation (CVs) were 5.1% and 16.5% for manual tracing, 1.4% and 2.3% for region growth, and 1.5% and 5.2% for directed segmentation. The average deviations from manual tracing were 9% for region growth and 5.7% for directed segmentation.

CONCLUSION

Both semiautomated methods were shown to have a significant advantage over manual tracing in terms of speed and precision. The accuracy of both methods was acceptable, given the high variability of the manual results.

Stochastic kinematic modeling and feature extraction for gait analysis

This research presents a new model-based approach toward the three-dimensional (3-D) tracking and extraction of gait and human motion. We suggest the use of a hierarchical, structural model of the human body that introduces the concept of soft kinematic constraints. These constraints take the form of a priori, stochastic distributions learned from previous configurations of the body exhibited during specific activities; they are used to supplement an existing motion model limited by hard kinematic constraints. We use time-varying parameters of the structural model to measure gait velocity, stance width, stride length, stance times, and other gait variables with multiple degrees of accuracy and robustness. To characterize tracking performance, we also introduce a novel geometric model of expected tracking failures. We demonstrate and quantify the performance of the suggested models using multi-view, video sequences of human movement captured in a complex home environment.

Opposite effects of lithium on proximal and distal caspases of immature and mature primary neurons correlate with earlier paradoxical actions on viability

To provide an explanation for earlier paradoxical findings of lithium on survival of mature and immature neurons, this study monitors changes in cytosolic caspases in rat cerebellar granule cells (CGC) grown 2-7 days in vitro (DIV), or in murine E-17 cortical neurons. Data show Li+ protects mature 7-DIV CGC parallel to a decrease in proximal and distal caspases but increases levels for immature 2-DIV-CGC or E-17 cortical neurons. Caspases mirror viability based on morphological analyses (dye uptake, phase-contrast, DNA fragmentation), and suggest protection occurs by suppressing activation of a cascade resulting in distal effectors that destroy proteins essential for neuronal survival. Protection was dose-dependent with EC50 3.0 mM and extended to 64 h in K+-serum deprived apoptotic media. Neuronal extracts contain a spectrum of proximal (-2, -8, -9) and distal (-3, -6) caspases sensitive to Li+ on assay with preferred peptide substrates and by immunoblotting. The lack of direct effect on activated cytosols indicates Li+ acts upstream only on intact cells, at sites for recruitment of pivotal procaspases. Alterations of procaspase-9 p46 and membrane-bound cytochrome c (Apaf-1) point to interaction with an intrinsic Mt-mediated pathway as one of the targets. The opposite effects on caspases and viability of immature or embryological neurons point to existence of alternative pathways that alter during neurite outgrowth suggesting the use of Li+ as a probe to unravel events relevant to neurogenesis.

Differential expression of carnosine, homocarnosine and N-acetyl-L-histidine hydrolytic activities in cultured rat macroglial cells

N-acetyl-L-histidine (NAH) and N-acetyl-L-aspartate (NAA) are representatives of two series of substances that are synthesized by neurons and other cells in the vertebrate central nervous system (CNS). Histidine containing homologs of NAH are beta-alanyl-L-histidine or carnosine (Carn) and gamma-aminobutyrl-L-histidine or homocarnosine (Hcarn). A homolog of NAA is N-acetylaspartylglutamate (NAAG). These substances belong to a unique group of osmolytes in that they are synthesized in cells that may not to be able to hydrolyze them, and are released in a regulated fashion to a second compartment where they can be rapidly hydrolyzed. In this investigation, the catabolic activities for NAH, Carn, and Hcarn in cultured macroglial cells and neurons have been measured, and the second compartment for NAH and Hcarn has been identified only with astrocytes. In addition, oligodendrocytes can only hydrolyze Carn, although Carn can also be hydrolyzed by astrocytes. Thus, astrocytes express hydrolytic activity against all three substrates, but oligodendrocytes can only act on Carn. The cellular separation of these hydrolytic enzyme activities, and the possible nature of the enzymes involved are discussed.

Pharmacogenetic screening for susceptibility to fetal malformations in women

OBJECTIVE

To present a review of the literature and research on the pharmacogenetics of congenital defects, with a focus on the need for predictive maternal genotype assays.

DATA SOURCE

MEDLINE searches (January 1985-January 1999), past reference reviews, and unpublished research.

STUDY SELECTION

Review of relevant human, animal, and basic science studies.

DATA EXTRACTION

Data on research on polymorphisms, genotyping, cytochrome P450 enzyme systems, epoxide hydrolase, folate metabolism, metabolism of anticonvulsant medications, molecular genetics of neural tube defects, variations in drug metabolism, and environmental exposures were evaluated.

DATA SYNTHESIS

Data synthesis includes not only a review of the literature but suggests ways such data might be used to facilitate the development of maternal genotype assays, with the goal of preventing birth defects.

CONCLUSIONS

Individuals vary in how they metabolize drugs and handle toxic environmental exposures. In an ideal pregnancy, there is no or limited exposure to medications and environmental agents. However, in women with chronic medical conditions such as heart disease and seizures, this is often not possible. Unfortunately, no techniques have been available to identify those at risk in this population. Gene polymorphisms for a specific enzyme may result in an absence or reduction in the level of enzyme activity or in no change at all, with little effect on the structure/function of the gene product(s); they are not associated with clinical phenotypes in either the mother or the fetus. Other polymorphisms may be only markers. Thus, developing genotyping assays for women that are predictive of phenotype expression in the fetus is the key to screening for polymorphisms. As more mutations are identified and clinical, pharmacologic, biologic, and pharmacokinetic relationships are established, using these polymorphisms to develop a genotyping assay for women may become a clinical reality, possibly leading to preventive prepregnancy or prenatal treatment that may play an increasingly effective role in maternal care.

Genetic and neuroradiological heterogeneity of double cortex syndrome

Mutations in the X-linked doublecortin gene appear in many sporadic cases of double cortex (DC; also known as subcortical band heterotopia), a neuronal migration disorder causing epilepsy and mental retardation. The purpose of this study was to examine why a significant percentage of sporadic DC patients had been found not to harbor doublecortin mutations and to determine whether clinical features or magnetic resonance imaging scan appearance could distinguish between patients with and without doublecortin mutations. Magnetic resonance imaging scan analysis differentiated patients into the following four groups: anterior biased/global DC with doublecortin mutation (16 of 30; 53%), anterior biased/global DC without mutation (8 of 30; 27%), posterior biased DC without mutation (3 of 30; 10%), and limited/unilateral DC without mutation (3 of 30; 10%). The presence of these atypical phenotypes suggests that other genetic loci or mosaicism at the doublecortin locus may be responsible for this diversity of DC cases.

Gangliosides attenuate ethanol-induced apoptosis in rat cerebellar granule neurons

Ethanol significantly enhances cell death of differentiated rat cerebellar granule neurons on culture in a serum-free medium containing a depolarizing concentration of KCl (25 mM), 5 microM MK-801 (an NMDA receptor antagonist), and 20-200 mM ethanol for 1-4 days. Cell death augmented by ethanol was concentration- and time-dependent with neurons displaying hallmark apoptotic morphology and DNA fragmentation that correlated with the activation of cytosolic caspase-3. Inclusion of 5 microM MK-801 or 100 microM glycine in culture media did not alter rates of cell death indicating ethanol toxicity is mediated via an NMDA receptor-independent pathway. Preincubation with 50 microM gangliosides GM1, GD1a, GD1b or GT1b for 2 h, or preincubation with 10 microM LIGA20 (a semisynthetic GM1 with N-dichloroacetylsphingosine) for 10 min, attenuated caspase-3 activity and ethanol-induced cell death. Data show native gangliosides and a synthetic derivative are potently neuroprotective in this model of ethanol toxicity, and potentially serve as useful probes to further unravel the mechanisms relevant to neuronal apoptosis.

Recent advances on neuronal caspases in development and neurodegeneration

In view of a large and growing literature, this overview emphasizes recent advances in neuronal caspases and their role in cell death. To provide historical perspective, morphology and methods are surveyed with emphasis on early studies on interleukin converting enzyme (ICE) as a prototype for identifying zymogen subunits. The unexpected homology of ICE (caspase-1) to Caenorhabditis elegans death gene CED-3 provided early clues linking caspases to programmed cell death, and led later to discovery of bcl-2 proteins (CED-9 homologs) and 'apoptosis associated factors' (Apafs). Availability of substrates, inhibitors, and cDNAs led to identification of up to 16 caspases as a new superfamily of unique cysteine proteinases targeting Asp groups. Those acting as putative death effectors dismantle neurons by catabolism of proteins essential for survival. Caspases degrade amyloid precursor protein (APP), presenilins (PS1, PS2), tau, and huntingtin, raising questions on their role in neurodegeneration. Brain contains 'inhibitors of apoptosis proteins' (IAPs) survivin and NAIP associated also with some neuronal disorders. Apoptotic stress in neurons initiates a chain of events leading to activation of distal caspases by pathways that remain to be fully mapped. Neuronal caspases play multiple roles for initiation and execution of cell death, for morphogenesis, and in non-mitotic neurons for homeostasis. Recent studies focus on cytochrome c as pivotal in mediating conversion of procaspase-9 as a major initiator for apoptosis. Identifying signaling pathways and related events paves the way to design useful therapeutic remedies to prevent neuronal loss in disease or aging.

The importance of folic acid

Folic acid is necessary for cell development; for the metabolism of specific biochemical reactions in the body, such as the conversion of homocysteine to methionine; and for the metabolism of specific anticonvulsant drugs. Folic acid has an interrelationship with vitamin B12. A deficiency of folate increases the risk of NTDs, as well as contributing to hyperhomocystinemia, a condition associated with increased cardiovascular disease and NTDs. For the prevention of NTDs, it is recommended that a woman of childbearing age consume a daily folate intake of 400 micrograms; however, the average dietary folate intake is half that amount, and the FDA folate fortification of cereal grains adds only 100 micrograms daily. The woman in her childbearing years does not meet the recommendation with dietary and food fortification. Periconceptional folic acid supplementation is essential, because the neural tube closes 23 to 27 days after conception. Therefore, a multiple vitamin containing folic acid is the practical solution at present if the food fortification is not increased. The bioavailability of folate in the vitamin preparation is approximately double that of dietary folate. Most preparations contain 400 micrograms of folic acid, and if the woman took a multiple vitamin (400 micrograms of folate) in addition to her diet (230 micrograms of folate), she would not exceed 1000 micrograms (1 mg) daily, which is considered the upper limit of daily folate ingestion by dietary fortification and supplementation before the masking of vitamin B12 becomes a concern. However, in this group of patients, pernicious anemia is rare. Regarding cardiovascular disease in men and women, there are no long-term studies showing the benefit of folic acid in reducing the homocysteine level. At present, there are only estimations. However, they should not be ignored. Although it is not the current standard of practice, adding a multiple vitamin containing folic acid to the regimen of men and women starting anticonvulsant medication should be considered in order to prevent the folate lowering observed with such commonly used drugs as PHT and carbamazepine. Women in childbearing years should be on a folic acid supplement when taking an anticonvulsant drug. In general, it appears that all men and women would benefit from increased folate intake. This can be accomplished through vitamin supplementation when there is compliance. However, if the food fortification for folate is increased in the future, then the issue of vitamin supplementation will have to be readdressed.

Drugs and smoking

Generally, one should keep in mind that if a smoker takes a drug that is metabolized primarily by the CYP 1A2 system, an increased dose may be required. The patient should be closely monitored if he or she is taking several medications that may inhibit or induce the CYP 1A2 isoenzyme. Hepatic enzyme metabolism does not completely explain the effects of smoking on drugs, however, because smokers may have different physiologic responses to pain and sedation that depend on changes in plasma protein binding and in the rate and efficacy of subcutaneous absorption. Most of the few sex/gender-analyzed pharmacokinetic studies in smokers occurred after 1995. It appears that the 1993 changes at the National Institutes of Health and the Food and Drug Administration regarding inclusion of women in clinical trials enabled these examinations to take place. Because smokers--who make up nearly a quarter of the U.S. adult population--tend to consume more medications than nonsmokers, this social habit should be considered one of the most important to impact on drug metabolism in both sexes.

Characterization of mutations in the gene doublecortin in patients with double cortex syndrome

Mutations in the X-linked gene doublecortin, which encodes a protein with no dear structural homologues, are found in pedigrees in which affected females show "double cortex" syndrome (DC; also known as subcortical band heterotopia or laminar heterotopia) and affected males show X-linked lissencephaly. Mutations in doublecortin also cause sporadic DC in females. To determine the incidence of doublecortin mutations in DC, we investigated a cohort of eight pedigrees and 47 sporadic patients with DC for mutations in the doublecortin open reading frame as assessed by single-stranded conformational polymorphism analysis. Mutations were identified in each of the eight DC pedigrees (100%), and in 18 of the 47 sporadic DC patients (38%). Identified mutations were of two types, protein truncation mutations and single amino acid substitution mutations. However, pedigrees with DC displayed almost exclusively single amino acid substitution mutations, suggesting that patients with these mutations may have less of a reproductive disadvantage versus those patients with protein truncation mutations. Single amino acid substitution mutations were tightly clustered in two regions of the open reading frame, suggesting that these two regions are critical for the function of the Doublecortin protein.

Multilocus linkage identifies two new loci for a mendelian form of stroke, cerebral cavernous malformation, at 7p15-13 and 3q25.2-27

Cerebral cavernous malformation (CCM) is a Mendelian model of stroke, characterized by focal abnormalities in small intracranial blood vessels leading to hemorrhage and consequent strokes and/or seizures. A significant fraction of cases is inherited as an autosomal dominant trait with incomplete penetrance. Among Hispanic Americans, virtually all CCM is attributable to a founder mutation localized to 7q ( CCM1 ). Recent analysis of non-Hispanic Caucasian kindreds, however, has excluded linkage to 7q in some, indicating at least one additional CCM locus. We now report analysis of linkage in 20 non-Hispanic Caucasian kindreds with familial CCM. In addition to linkage to CCM1, analysis of linkage demonstrates linkage to two new loci, CCM2 at 7p13-15 and CCM3 at 3q25.2-27. Multilocus analysis yields a maximum lod score of 14.11, with 40% of kindreds linked to CCM1, 20% linked to CCM2 and 40% linked to CCM3, with highly significant evidence for linkage to three loci (linkage to three loci supported with an odds ratio of 2.6 x 10(5):1 over linkage to two loci and 1.6 x 10(9):1 over linkage to one locus). Multipoint analysis among families with high posterior probabilities of linkage to each locus refines the locations of CCM2 and CCM3 to approximately 22 cM intervals. Linkage to these three loci can account for inheritance of CCM in all kindreds studied. Significant locus-specific differences in penetrance are identified. These findings have implications for genetic testing of this disorder and represent an important step toward identification of the molecular basis of this disease.

Drug and environmental factors associated with adverse pregnancy outcomes. Part III: Folic acid: pharmacology, therapeutic recommendations, and economics

OBJECTIVE

To review folic acid's mechanism of action, adverse effects, therapeutic recommendations, compliance, and cost.

DATA SOURCES

A MEDLINE search was conducted through December 1997. Additional sources were obtained from Current Contents and citations from the references obtained. Search terms included folate, folic acid, neural tube defect, homocysteine, and methylenetetrahydrofolate reductase.

STUDY SELECTION

Animal and human studies examining the effects of folate were reviewed.

DATA EXTRACTION

Data collected included mechanism of action, safety issues, dosing recommendations, compliance with recommendations, and economics.

DATA SYNTHESIS

Folic acid decreases neural tube defect risk through an effect on methionine-homocysteine metabolism. In addition, increased folate intake may reduce cardiovascular morbidity and mortality. Since toxicity is minimal, everyone can potentially benefit from increased folate consumption. To help achieve this, the Food and Drug Administration has mandated that cereal grain be fortified with 140 micrograms of folic acid per 100 g of grain, which will add approximately 0.1 mg of folate to the average diet. Studies recommend supplementing with 0.2 mg to promote optimal homocysteine concentrations and for preventing neural tube defects.

CONCLUSIONS

Despite fortification, most women will still receive less folate than the 0.4 mg/d recommended by the Public Health Service. All population groups would benefit from increased folate intake. Current studies indicate 200 micrograms/d may be the minimum effective amount of fortification needed for normalizing homocysteine concentrations and preventing a significant number of neural tube defects; thus, a higher level of food fortification may be warranted.

Drug and environmental factors associated with adverse pregnancy outcomes. Part II: Improvement with folic acid

OBJECTIVE

To provide a comprehensive review of periconceptional folic acid supplementation and factors affecting folate supplementation trials.

DATA SOURCES

A MEDLINE search was conducted through December 1997. Additional sources were obtained from Current Contents and citations from the references obtained. Search terms included folate, folic acid, neural tube defect, spina bifida, and anencephaly.

STUDY SELECTION

Relevant animal and human studies examining the effects of folate were reviewed.

DATA EXTRACTION

Data collected included: type of study, folate dosing, dietary folate intake, serum and red blood cell folate concentrations, type of defect(s) studied, vitamin usage, parental risk factors, factors affecting trial results.

DATA SYNTHESIS

Nine key factors have been identified that affect outcomes of folic acid supplementation trials. Daily doses of 0.8 mg decreased the occurrence and doses of 4 mg decreased the recurrence of neural tube defects in randomized clinical trials. Since lower folic acid doses were effective in nonrandomized trials, research is needed to determine the lowest effective dosage. Other benefits involving pregnancy outcome are suggested.

CONCLUSIONS

Women of childbearing age should take a daily folic acid supplement to reduce the risk of pregnancies resulting in infants with a neural tube defect and other potential adverse pregnancy outcomes. Further health benefits from folic acid supplementation are reviewed in Part III of this series.

Drug and environmental factors associated with adverse pregnancy outcomes. Part I: Antiepileptic drugs, contraceptives, smoking, and folate

OBJECTIVE

Part I of this review examines the relationship between antiepileptic drugs (AEDs) and pregnancy outcomes. Drug-induced folate deficiency and the role of AED metabolism are emphasized. Part II will discuss periconceptional folate supplementation for prevention of birth defects. Part III will discuss the mechanism of folate's protective effect, therapeutic recommendations, compliance, and cost.

DATA SOURCES

A MEDLINE search was conducted for journal articles published through December 1997. Additional sources were obtained from Current Contents and citations from the references obtained. Search terms included phenytoin, carbamazepine, phenobarbital, primidone, valproic acid, oral contraceptives, clomiphene, drug-induced abnormalities, spina bifida, anencephaly, neural tube defect, folate, folic acid, and folic acid deficiency.

STUDY SELECTION

Relevant animal and human studies examining the effects of AEDs, smoking, and oral contraceptives on folate status and pregnancy outcome are reviewed.

DATA EXTRACTION

Studies and case reports were interpreted. Data extracted included dosing, serum and red blood cell folate concentrations, teratogenicity of anticonvulsant medications, metabolism of AEDs and folate, and genetic susceptibility to AED-induced teratogenicity.

DATA SYNTHESIS

Low serum and red blood cell folate concentrations are associated with adverse pregnancy outcomes. Decreases in serum folate are seen with AEDs, oral contraceptives, and smoking. Since similar birth defects are observed with multiple AEDs, metabolism of aromatic AEDs to epoxide metabolites and genetic factors may play a role in teratogenesis.

CONCLUSIONS

Adequate prepregnancy planning is essential for women who have epilepsy. Women receiving folate-lowering drugs may be at increased risk of adverse pregnancy outcomes. Therefore, epileptic women contemplating pregnancy should be treated with the minimum number of folate-lowering drugs possible and receive folic acid supplementation.

The semisynthetic glycosphingolipid LIGA20 potently protects neurons against apoptosis

LIGA20 (a semisynthetic GM1 with n-dichloroacetyl sphingosine) having antinecrotic properties was evaluated as an antiapoptotic agent using cerebellar granule cells as a neuronal model. Neurons exposed to medium containing 5 mM K+ in absence of serum (apoptotic medium) for up to 22 h resulted in 65% cell death, accompanied by oligonucleosomal laddering, and a 15-fold-increase in caspase-3 activity. The relationships between times required for enzyme activation and cell death suggests a linkage between these two events. Pretreatment with 10 microM LIGA20 for 10 min significantly attenuated the aforementioned apoptotic changes. LIGA20 also attenuated apoptosis induced by Pb2+, ethanol, and C6-ceramide. Data show that LIGA20 is a versatile neuroprotective agent protecting cells from multiple pathways of cell death.

Activation of caspase-3 and apoptosis in cerebellar granule cells

Caspase-3 activity increased dramatically in cytosolic extracts of rat cerebellar granule cells exposed to apoptotic conditions (basal medium Eagle (BME) containing 5 mM K+ without serum) when assayed with Ac-DEVD-amc, but not with Ac-YVAD-afc, a preferred substrate for caspase-1. This provided a basis to examine relationships between enzyme activity and cell viability for purposes of selecting an optimal time for comparing neuroprotective agents or strategies. Exposure of neurons to an apoptotic medium containing 5 mM K+ in absence of serum led to a rapid 5- to 10-fold increase in caspase-3 within 2-4 hr but without significant cell loss, or morphological alterations. Exposure to apoptotic medium followed by replacement with maintenance medium containing 25 mM K+ and serum led to a rapid fall in caspase-3 and prevention of cell death. This strategy was not effective after 13 hr exposure despite a large fall in enzyme activity. These temporal changes infer systems for rapid enzyme turnover and/or activation of cytoplasmic components linked to later DNA degradation. The effects of cycloheximide point to requirements for protein synthesis, and those of Glu exclude a caspase-3 dependent pathway for necrotic cell damage. Brief treatment with 10 microM LIGA20, an anti-necrotic agent, also attenuated cell loss and caspase-3 activity, indicating a broad spectrum of neuroprotection. Rapid and long-lasting effects, together with its biophysical properties, suggest that this semisynthetic ganglioside acted upstream at or near a membrane site. As such, gangliosides provide useful agents to further probe pathways relevant to neuronal death in culture.

X-linked female band heterotopia-male lissencephaly syndrome

We report a family with band heterotopia in a mother and daughter and lissencephaly in a son (X-linked inheritance pattern). Postmortem examination of the boy revealed classical lissencephaly and, among other findings, simplified and discontinuous inferior olives without inferior olivary heterotopia. The absence of inferior olivary heterotopia may distinguish X-linked lissencephaly from other conditions with classic lissencephaly such as Miller-Dieker syndrome.