Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0036572 (seizures)
 80,221 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Neuropsychologists who serve as members of an epilepsy surgery team are often asked to provide information regarding localized cerebral dysfunction that may relate to the seizure focus in patients with intractable temporal lobe epilepsy (TLE). However, the rate at which neuropsychological (NP) assessment results correspond with the side of seizure focus (i.e., left vs. right) in TLE patients is unknown. The majority of literature in this area has focused on the ability of single NP tests to detect lateralized cognitive dysfunction in groups of TLE patients, with mixed findings and few consistent replications. The primary purpose of this study was to examine the rate at which qualitative clinician interpretations of NP profiles agree with seizure lateralization as determined by a multidisciplinary surgery team in temporal lobectomy candidates. Quantitative analyses of single NP test scores and groups of test scores (i.e., cognitive domain composite scores) were also conducted to examine their effectiveness in discriminating left from right TLE groups. Only four of the 19 NP test variables and three of the nine composite cognitive domain scores significantly differed between the groups. However, clinician interpretation of NP profiles agreed with the surgery conference team's determination of seizure laterality in two-thirds of cases. These findings suggest that qualitative aspects of NP performance play an important role in identifying lateralized cerebral dysfunction in TLE patients, and provide additional support for the use of NP assessment results in the selection of temporal lobectomy candidates.
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PMID:Quantitative and qualitative interpretation of neuropsychological data in the assessment of temporal lobectomy candidates. 1152 40

The neuronal ceroid lipofuscinoses (NCL) are a large group of autosomal recessive lysosomal storage disorders with both enzymatic deficiency and structural protein dysfunction. Previously, diagnosis of NCL was based on age at onset and clinicopathologic (C-P) findings, classified as 1) infantile (INCL), 2) late infantile (LINCL), 3) juvenile (JNCL), and 4) adult (ANCL). Most patients with NCL have progressive ocular and cerebral dysfunction, including cognitive/motor dysfunction and uncontrolled seizures. After reviewing 319 patients with NCL, the authors found that 64 (20%) did not fit into this classification of NCL. With research progress, four additional forms have been recognized: 5) Finnish, 6) Gypsy/Indian, and 7) Turkish variants of LINCL and 8) northern epilepsy, also known as progressive epilepsy with mental retardation. These eight NCL forms resulted from 100 different mutations on genes CLN1to CLN8 causing different phenotypes (http://www.ucl.ac.uk/ncl). The genes CLN1 and CLN2 encode lysosomal palmitoyl protein thioesterase and tripeptidyl peptidase 1. The function of CLN3, CLN5, and CLN8 gene-encoded products is unknown, although their predicted amino acid sequences suggest they have a transmembrane topology. The diagnosis of NCL is based on C-P findings, enzymatic assay, and molecular genetic testing. Before biochemical and genetic tests are conducted, ultrastructural studies (i.e., blood [buffy coat] or punch biopsies [skin, conjunctiva]) must be performed to confirm the presence and nature of lysosomal storage material (fingerprint or curvilinear profiles or granular osmiophilic deposits). The recognition of variable onset from infancy to middle age supersedes the traditional emphasis on age-related NCL forms.
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PMID:Pheno/genotypic correlations of neuronal ceroid lipofuscinoses. 1154 35

Functional mapping of the human brain has made tremendous progress in the past years thanks to new technical developments. Imaging methods are now available; they allow to study brain functions with high spatial and temporal resolution. Single photon emission computer tomography (SPECT), positron emission tomography (PET), functional magnetic resonance imaging (fMRI) and high resolution electro- and magnetoencephalography (EEG and MEG) are currently intensively applied techniques to functional studies, each one having specific properties concerning spatial and temporal resolution. The success of these methods in basic neuroscience research has led to the demand for applying them to clinical questions. Diseases of the central nervous system that lead to brain dysfunction can be ideally explored using these techniques. Of particular importance are those diseases in which a focal neuronal dysfunction is the primary cause and where surgical resection of this focus might be the cure. This is often the case for epilepsy, where a discrete primary focus might exist from which pathological rhythms evolve and propagate throughout the brain, leading to seizures that severely handicap the patient. Surgical resection of the primary focus is only possible if the focus can be exactly localized and adequately separated from functionally important areas. This is where these new functional imaging tools become important. The use of SPECT and PET for focus localization has been most extensively studied and their specificity and sensitivity are intensively discussed. In the last few years functional MRI has evolved as a new interesting tool in epileptic focus localization. The most important limitation of these techniques, however, is the temporal resolution. Since epileptic activity can propagate very fast, several hyper- or hypoactive regions are seen in the images and primary areas cannot be distinguished from regions of propagation. The only methods that have sufficient temporal resolution to follow neuronal activity in real time are the electrophysiological measures, i.e. the EEG and the MEG. Localization of the sources in the brain that produced a given surface electromagnetic field has become possible through algorithms that solve the so-called "inverse problem". Several different algorithms exist and many groups begun to apply them to epileptic data with the aim to localize the focus of the pathological electrical discharges. This review article discusses the use of distributed EEG source localization procedures in the presurgical evaluation of patients with intractable focal epilepsy. In contrast to equivalent dipole models, distributed localization methods do not localize one active point in the brain but rather assume extended active areas, which is generally the case in epileptic activity. The methods shown here are based on linear numerical methods and are therefore less prone to errors when working with scattered solution spaces such as the one defined by anatomical constraints. Solutions constraint to the gray matter determined in the individual MRI are shown here. We illustrate three methods to increase the spatial resolution of the source localization procedures: One is to increase the number of recording channels to more than 100, the second to use linear methods of high precision to detect focal sources (EPIFOCUS), and the third to combine EEG source localization with EEG-triggered functional magnetic resonance imaging. The importance of EEG source localization for the interpretation of fMRI data will be particularly discussed in view of the important difference of the temporal resolution by the two methods. The localization methods can be applied to interictal as well as to ictal activity. In case of analysis of ictal EEG we propose to use full scalp frequency analysis to determine the time period of seizure onset and to localize the sources of the initial dominant frequency.
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PMID:Localization of distributed sources and comparison with functional MRI. 1178 Dec

The background activity on neonatal electroencephalography (EEG) is a good prognostic indicator. An EEG suppression burst pattern usually indicates severe brain dysfunction and has been considered to be associated with a serious neurodevelopmental outcome. We report here a 2-year-old girl who developed generalized convulsions without any perinatal brain insult at 3 days of age. At that time, her EEG constantly showed a suppression burst pattern, and her prognosis was considered to be poor. However, her seizures were well controlled with the oral administration of carbamazepine, and the suppression burst pattern on EEG disappeared at 27 days of age. Unexpectedly, she developed normally for the following 2 years. Although children with normal development, despite the appearance of suppression burst, are extremely rare, and the reason why this patient showed a favorable outcome remains unknown, the clinical course of this patient proved that an EEG suppression burst pattern is not always associated with a poor prognosis.
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PMID:Normally developed infant with a suppression burst pattern on electroencephalography in the neonatal period. 1215 May 88

Growing evidence indicates that the effects of antiepileptic drugs on childhood epilepsies are partly linked to the specific type of epilepsy or epilepsy syndrome. Most (but not all) types of epilepsy can be classified into categories that are conceptually meaningful. It is likewise logical to set treatment targets and to estimate the risks according to the main syndromic groups, as they share common, electroclinical presentations and long-term prognosis. Treatment should then be adjusted to each patient's clinical characteristics. Treatment should be started soon, whenever there is indication that delay would harm the child. However, if seizures are not disabling, treatment may be delayed, in order to acquire more knowledge about the spontaneous expression of the disorder and the plan thoughtfully explained to the parents. In children presenting with partial symptomatic or cryptogenic epilepsy, it is important to assess the patient's response to several different drugs. However, in patients regarded as having refractory epilepsy, possibilities for a surgical solution must be evaluated early in the course of the disease. In severe epileptic encephalopathies, complete seizure control is impossible and, ideally, treatment should provide as much integration and autonomy, with alleviation of frequent seizures. Again, this should be carefully explained to the parents. In children with severe epileptiform EEG abnormalities coexisting with brain dysfunction (diffuse or specific), the extent of EEG-related neurological dysfunction should be determined, and vigorous treatment should be started to abate its effects. Finally, seizures could be worsened by inappropriate drugs, paradoxical reaction or intoxication. Severe childhood epilepsies are particularly at risk and mild idiopathic epilepsies may be transformed into severe disorders, priming a vicious circle of heavy treatment, whereby the original disorder is no longer recognizable.
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PMID:Rationale for treating epilepsy in children. 1242 80

Until the introduction of antibiotics in the 1930s and 1940s, acute bacterial meningitis was fatal in most cases. Since then it has become curable with a variable mortality and morbidity rate for individual pathogens and patients. Neuropathological and clinical studies have shown that a fatal outcome of the disease is often due to central nervous system (CNS) complications including cerebrovascular involvement, brain oedema formation, and hydrocephalus resulting in increased intracranial pressure and seizure activity. During recent years, experimental studies with animal models have substantially increased our knowledge of the interactions of bacterial pathogens with mammalian cells and their entry into the CNS, and the complex pathophysiological mechanisms of brain dysfunction during acute bacterial meningitis. There is now a substantial body of evidence that cytokines, chemokines, proteolytic enzymes, and oxidants are involved in the inflammatory cascade that leads to tissue destruction in bacterial meningitis. Genetic targeting and/or pharmacological blockade of these pathways was beneficial in experimental bacterial meningitis. Apart from dexamethasone, these treatment strategies hold major promise for the adjunctive therapy of acute bacterial meningitis in clinical practice.
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PMID:Pathogenesis and pathophysiology of pneumococcal meningitis. 1246 88

Intrathecal methotrexate in children with leukemia is known to cause seizures, dementia, leukoencephalopathy, and cognitive dysfunction after long-term treatment. To investigate the cognitive dysfunction, male Wistar rats were given multiple intracerebroventricular injections of methotrexate. Its effect on behaviour was tested in the two-compartment conditioned avoidance task and dark-bright arena test. Levels of brain amines in the hippocampal region of the brain were estimated by HPLC. The qualitative and quantitative histopathological changes in the different regions of the hippocampus were studied by cresyl violet staining. Multiple injections (1 or 2 mg/kg) produced convulsions and learning and memory impairment but did not induce anxiolytic activity. They also reduced concentrations of all three brain amines (norepinephrine, dopamine, and serotonin) and the serotonin metabolite 5-hydroxyindoleacetic acid. The CA4 region of the hippocampus was severely affected by intraventricular methotrexate. Disruption of brain monoamines has been proposed as a cause of brain dysfunction from this chemotherapy, and that disruption may in turn involve cytotoxic effects of methotrexate on brain tissue. The outcomes of this study may have therapeutic implications in the management of cancer conditions, particularly in childhood lymphoblastic leukemia.
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PMID:Hippocampal brain amines in methotrexate-induced learning and memory deficit. 1248 27

The metabolic and anatomical substrate of most forms of mental retardation is not known. Because the basis of normal brain function is not sufficiently understood, the basis of abnormal function is understood poorly. Even in disorders where the fundamental biochemical defect is known, such as phenylketonuria (PKU) and other enzyme defects, the exact basis for brain dysfunction is uncertain. The outcome for treated PKU, galactosemia, homocystinuria, and lysosomal disorders is not yet optimal. The various forms of nonketotic hyperglycinemia often respond poorly to current therapy. Less familiar disorders, with or without seizures, such as deficient synthesis of serine or creatine and impaired glucose transport into the brain, and disorders with variable malformations, such as Smith-Lemli-Opitz (SLO) syndrome and the congenital disorders of glycosylation (CDGs), may initially be thought to be a nonspecific form of developmental delay. Less familiar disorders, with or without seizures and disorders with variable malformations may initially be thought to be a nonspecific form of developmental delay. Simple tests of urine, blood, and cerebrospinal fluid may lead to a diagnosis, accurate genetic counseling, and better treatment. Metabolic brain imaging (magnetic resonance spectroscopy (MRS)) has also helped to reveal biochemical abnormalities within the brain.
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PMID:Metabolic disorders and mental retardation. 1256 Oct 56

Kava is an extract from the Piper methysticum Forst. f. plant that has been consumed in the Pacific islands for millennia and more recently, among indigenous populations, in northern Australia and throughout the Western world as an herbal medicine. Through alterations on neuronal excitation, kava induces muscle relaxation, anasthesia, and has anxiolytic properties. There have been several isolated reports of psychotic syndromes, severe choreoathetosis and possible seizures following kava use. However, there is no conclusive evidence that kava interferes with normal cognitive processes. We tested a group of current, ex, and nonkava users among an indigenous population in northern Australia, using saccade and cognitive tests that have proven cross-cultural validity and are sensitive to subtle disruptions of the brain arising from substance abuse or neuropsychiatric illness. Despite collecting data from among the heaviest reported kava drinkers in the world, we found no impairment in cognitive or saccade function in individuals who were currently heavy kava users (and had been for up to 18 years), nor was there any impairment in individuals who had been heavy kava users in the past but had abstained for longer than 6 months. Current and ex-kava users showed a higher rate of kava dermopathy, lower body mass index, lowered blood lymphocytes and, in addition, current kava users showed elevated liver enzymes. While there has recently been increasing concern about potentially fatal liver damage attributed to kava use, we have found no evidence of brain dysfunction in heavy and long-term kava users.
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PMID:Saccade and cognitive function in chronic kava users. 1258 93

Patients with developmental disabilities, including retardation and global developmental delay, are not ideal candidates for epilepsy surgery. Because they have an increased likelihood of diffuse brain dysfunction and multifocal or generalized epileptogenic zones, there is an increased chance that a focal cortical resection will not confer a major improvement in their seizure frequency and severity. There is also increased concern that cortical resection will lead to increase in the patient's disability. However, by applying the basic principles of epilepsy surgery selection (i.e., convergence of multiple lines of localizing evidence) to this population, patients with a reasonable likelihood of good seizure control can be identified. Various means of localizing seizure onset are reviewed, including history and examination, electroencephalography, magnetic resonance imaging, position emission tomography, single-photon-emission tomography, and magnetoencephalography.
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PMID:Treatment considerations: role of surgery. 1260 10


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