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)

Direct and indirect evidence suggests that Na+/K(+)-ATPase activity is reduced or insufficient to maintain ionic balances during and immediately after episodes of ischemia, hypoglycemia, epilepsy, and after administration of excitotoxins (glutamate agonists). Recent results show that inhibition of this enzyme results in neuronal death, and thus a hypothesis is proposed that a reduction and/or inhibition of this enzyme contributes to producing the central neuropathy found in the above disorders, and identifies potential mechanisms involved. While the extent of inhibition of Na+/K(+)-ATPase during ischemia, hypoglycemia and epilepsy may be insufficient to cause neuronal death by itself, unless the inhibition is severe and prolonged, there are a number of interactions which can lead to a potentiation of the neurotoxic actions of glutamate, a prime candidate for causing part of the damage following trauma. Presynaptically, inhibition of the Na+/K(+)-ATPase destroys the sodium gradient which drives the uptake of acidic amino acids and a number of other neurotransmitters. This results in both a block of reuptake and a stimulation of the release not only of glutamate but also of other neurotransmitters which modulate the neurotoxicity of glutamate. An exocytotic release of glutamate can also occur as inhibition of the enzyme causes depolarization of the membrane, but exocytosis is only possible when ATP levels are sufficiently high. Postsynaptically, the depolarization could alleviate the magnesium block of NMDA receptors, a major mechanism for glutamate-induced neurotoxicity, while massive depolarization results in seizure activity. With less severe inhibition, the retention of sodium results in osmotic swelling and possible cellular lysis. A build-up of intracellular calcium also occurs via voltage-gated calcium channels following depolarization and as a consequence of a failure of the sodium-calcium exchange system, maintained by the sodium gradient.
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PMID:Inhibition of sodium-potassium-ATPase: a potentially ubiquitous mechanism contributing to central nervous system neuropathology. 166 97

A young woman with acute intermittent porphyria (AIP) and juvenile myoclonic epilepsy began to have generalized tonic-clonic seizures (GTCs) at age 13. Subsequently, she had myoclonic seizures, which were often precipitated by visual stimulation, tended to occur in the morning, and sometimes evolved into GTCs. Valproate (VPA) resulted in a worsening of latent AIP, and treatment with a combination of phenytoin (PHT), carbamazepine (CBZ), and clonazepam (CZP) led to severe neuropathy of AIP and an electrolyte imbalance. These conditions were improved by water restriction, infusion of high doses of carbohydrates, and discontinuation of all antiepileptic drugs (AEDs) except for CZP. CZP appeared to be effective both in improving GTCs and myoclonic seizures and did not induce any symptoms of AIP. CZP may be porphyrogenic but can be used safely at a low dose for treatment of epilepsy in patients with AIP.
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PMID:Acute intermittent porphyria and epilepsy: safety of clonazepam. 173 41

A prospective study of the neurological manifestations in all patients with systemic lupus erythematous (SLE) was conducted between February 1985 to January 1989. Excluding herpes zoster infection of peripheral or cranial nerves, post-herpetic neuralgia and migraine, 36 neurological episodes occurred in 33 patients. The presenting symptoms were mental confusion (10), psychosis (five), seizures (six), focal neurological deficit (three), coma (two), headache (five), blurring of vision (three), neuropathy (one) and myelopathy (one). Of these manifestations, only eight episodes were due to primary involvement by SLE: psychosis (two), seizure (two), multiple cerebral infarcts (one), papillitis (one), neuropathy (one) and myelopathy (one). Infection was the most common secondary cause of neurological episodes: all 10 episodes of mental confusion (fungal seven, pyogenic two, tuberculous one, nocardial one); two of six seizures (tuberculous one, pyogenic one); all five headaches (tuberculous meningitis three, cryptococcal meningitis two). The other secondary causes included steroid psychosis (two), hypertensive encephalopathy with seizure (one) and hypertensive retinopathy (one). Three of five cases of focal neurological deficit were due to macrovascular disease rather than to vasculitic infarction. We concluded that cerebral psychosis was a relatively rare presentation in our patients with SLE. In patients who presented with a neurological problem, especially mental confusion, efforts should be made to ascertain the underlying cause, especially if this may be an infection.
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PMID:Neurological manifestations of systemic lupus erythematosus: a prospective study. 180 Oct 58

Using [18F]dopa, [11C]raclopride, C15O2, and positron emission tomography, we have assessed striatal dopamine storage capacity, dopamine D2-receptor integrity, and regional cerebral blood flow, respectively, of 6 patients with neuroacanthocytosis. The patients with neurocanthocytosis all had chorea and variable combinations of seizures, dementia, axonal neuropathy, and orolingual self-multiation. [18F]dopa positron emmission tomographic findings were compared with 30 normal controls and 16 patients with sporadic, L-dopa-responsive, Parkinson's disease. Caudate and anterior putamen [18F]dopa uptake were normal in patients with neuroacanthocytosis, but mean posterior putamen [18F]dopa uptake was reduced to 42% of normal, similar to that in patients with Parkinson's disease. In patients with neuroacanthocytosis, mean equilibrium caudate: cerebellum and putamen: cerebellum [11C]raclopride uptake ratios were reduced to 54% and 62% of normal, compatible with a 65% and 53% loss of caudate and putamen D2-receptor-binding sites, respectively. Striatal and frontal blood flow was also depressed. The severe loss of D2-receptor-bearing striatal neuron, with concomitant loss of dopaminergic projections from the nigra to the posterior putamen, is consistent with both chorea and extrapyramidal rigidity being features of patients with neuroacanthocytosis.
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PMID:Presynaptic and postsynaptic striatal dopaminergic function in neuroacanthocytosis: a positron emission tomographic study. 189 9

Nineteen cases are described, including 12 cases from three different families and 7 nonfamilial cases, in which multisystem neurological disease was associated with acanthocytosis in peripheral blood and normal plasma lipoproteins. Mild acanthocytosis can easily be overlooked, and scanning electron microscopy may be helpful. Some neurologically asymptomatic relatives with significant acanthocytosis were identified during family screening, including some who were clinically affected. The mean age of onset was 32 (range 8-62) yrs and the clinical course was usually progressive but there was marked phenotypic variation. Cognitive impairment, psychiatric features and organic personality change occurred in over half the cases, and more than one-third had seizures. Orofaciolingual involuntary movements and pseudobulbar disturbance commonly caused dysphagia and dysarthria that was sometimes severe, but biting of the lips or tongue was rarely seen. Chorea was seen in almost all symptomatic cases but dystonia, tics, involuntary vocalizations and akinetic-rigid features also occurred. Two cases had no movement disorder at all. Computerized tomography often demonstrated cerebral atrophy. Caudate atrophy was seen less commonly, and nonspecific focal and symmetric signal abnormalities from the caudate or lentiform nuclei were seen by magnetic resonance imaging in 3 out of 4 cases. Depression or absence of tendon reflexes was noted in 13 cases and neurophysiological abnormalities often indicated an axonal neuropathy. Sural nerve biopsies from 3 cases showed evidence of a chronic axonal neuropathy with prominent regenerative activity, predominantly affecting the large diameter myelinated fibres. Serum creatine kinase activity was increased in 11 cases but without clinical evidence of a myopathy. Postmortem neuropathological examination in 1 case revealed extensive neuronal loss and gliosis affecting the corpus striatum, pallidum, and the substantia nigra, especially the pars reticulata. The cerebral cortex appeared spared and the spinal cord showed no evidence of anterior horn cell loss. Two examples of the McLeod phenotype, an X-linked abnormality of expression of Kell blood group antigens, were identified in a single family and included 1 female. The genetics of neuroacanthocytosis are unclear and probably heterogeneous, but the available pedigree data and the association with the McLeod phenotype suggest that there may be a locus for this disorder on the short arm of the X chromosome.
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PMID:Neuroacanthocytosis. A clinical, haematological and pathological study of 19 cases. 199 79

Ataxic hemiparesis (AH) is a clinical entity in which minimal pyramidal weakness is associated with same-sided motor ataxia. It may be caused by a lesion of the pons or of cerebro-cerebellar and corticospinal fibers in other areas. Associated symptoms help in the clinical localization of a syndrome that has to be differentiated from lobar ataxias (frontal, parietal lobe), sensory ataxia accompanying spinal cord, corticospinal weakness and ataxic neuropathy. We report 3 cases of AH caused by a lesion in the contralateral cerebral cortex: 2 were cases of postictal seizure while the third patient had left ataxic hemiparesis, left focal motor seizures and cortical memory loss. All 3 patients recovered within 7 days. AH as a postictal phenomenon has not previously been reported.
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PMID:Reversible postictal ataxic hemiparesis. 201 27

Cocaine is increasingly used by drug addicts. It is considered harmless, but numerous, varied and often serious complications due to its abuse have been published. Among these, neurological complications are in the forefront. They include generalized or partial epileptic seizures, ischaemic or haemorrhagic cerebral vascular accidents, visual loss caused by optic neuropathy or by retinal artery occlusion, headaches and exacerbation of tics. Infections of the central nervous system are possible via endocarditis or septicaemia of venous or nasal origin. Neurological disorders may also occur as a consequence of a major cardiovascular complication induced by cocaine (myocardial infarction and/or dysrhythmia, aortic dissection). These neurological complications are unpredictable, and they weigh heavily on the functional and sometimes vital prognosis in habitual or occasional cocaine abusers.
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PMID:[Neurologic complications of cocaine abuse]. 214 Nov 59

Many conditions in clinical neurology may be responsive to pyridoxine as a therapeutic agent. The current difficulty is in trying to isolate the conditions that are most likely to respond. Treating seizures is a major part of a neurologic practice. Our current therapeutic agents are only partially successful and limited by multiple side effects. One problem is that patients often have to take these agents for an entire lifetime, further raising the risk of toxicity. If pyridoxine supplementation can improve the efficacy of currently used medications, it will be gladly accepted into our therapeutic arsenal. Headache, chronic pain, and depression all appear to run together in many of our patients. The observations that serotonin deficiency is a common thread between them and that pyridoxine can raise serotonin levels open a wide range of therapeutic options. Small studies have been carried out with mixed success. Comparison with amitriptyline in the treatment of headache appears to show about equal efficacy, although side effects would be expected to be more of a problem with the amitriptyline. Behavioral disorders are relatively common and continue to be a major problem, disrupting the lives of the patients and their families. Current treatments are not acceptable to most people because of the risk of side effects with long-term usage. If, as Dr. Feingold suggests, many of these problems are caused by "toxic" exposures to chemicals that are pyridoxine antagonists, supplementation at early ages may reduce the incidence of hyperactivity and aggressive behavior. This raises the question of safety. Is pyridoxine safe for long-term use in large segments of the population, including children? The studies on children with Down's syndrome and autism, utilizing much higher doses than are used for other therapeutic purposes, seem to indicate relative safety if carefully monitored. Studies involving large population groups with carpal tunnel syndrome, all adults, using 100-150 mg/day have shown minimal or no toxicity in five- to 10-year studies. Women self-medicating for PMS taking 500 to 5000 mg/day have shown peripheral neuropathy within one to three years. It would appear from this retrospective analysis that pyridoxine is safe at doses of 100 mg/day or less in adults. In children there is not enough data to make any sort of suggestion. Because the major neurologic complication is a peripheral neuropathy and the causes of this condition are myriad, pyridoxine may cause neuropathy only in patients with a pre-existing susceptibility to this condition.
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PMID:Vitamin B6 in clinical neurology. 216 44

An 11-year-old girl was found to have severely reduced beta-galactocerebrosidase activity as evidence of late-onset globoid cell leukodystrophy, while her mother had almost normal enzyme activity in circulating white blood cells. Clinically, the patient showed a remitting course marked by seizures, ataxia, white-matter disease on computed tomographic scan, and reduced conduction velocities of peripheral nerves. Symptoms improved somewhat around the age of 10 years. Two sural nerve biopsies, performed 6 years apart, disclosed a demyelinating neuropathy. By electron microscopy, membrane-bound vacuolar lysosomes in Schwann cells of myelinated axons, unlike the typical needlelike inclusions seen in classic infantile globoid cell leukodystrophy, were present in both specimens. Thus, clinical, morphologic, and biochemical data in this patient--and her mother--emphasize, compared with past reports on late-onset globoid cell leukodystrophy, considerable variation in the nosologic spectrum of late-onset globoid cell leukodystrophy and conspicuous differences from classic infantile globoid cell leukodystrophy.
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PMID:Late-onset globoid cell leukodystrophy: unusual ultrastructural pathology and subtotal beta-galactocerebrosidase deficiency. 217 71

Lumbosacral evoked potentials (EP) following stimulation of the posterior tibial nerve at the ankle were recorded with surface electrodes at 5 cm intervals from the lower lumbar to the lower thoracic levels and the site of maximum amplitude was determined by monopolar and bipolar recordings in 27 normal subjects, 37 epileptics receiving anticonvulsant therapy and 22 patients with subacute myelo-optico-neuropathy (SMON). The amplitude of EP in monopolar recording with a reference on the contralateral knee was usually maximum 10 cm above the Jacoby line, which nearly corresponded to the 1st lumbar or 12th thoracic vertebral level. The entire nerve conduction velocity (ENCV) was calculated by dividing the distance from the ankle to the level of maximum amplitude by the peak latency of the N21 or P17. The latency of N21 at the level of maximum evoked potential was used for determining ENCV. The mean ENCV calculated using the peak latency N21 was 49.8 (1.97) m/sec in monopolar recording and 51.2 (2.48) m/sec in bipolar recording, and these values were considered to correspond the sensory conduction along the entire posterior tibial nerve. In epileptic patients mainly treated with anticonvulsant drugs such as phenytoin and phenobarbital, the ENCV was reduced in those treated for over 13 years and in those whose illness was poorly controlled, or large doses were necessary for seizure control. In SMON patients, a significant decrease in ENCV was found in the group under 60 years old in comparison with the normal control group.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Nerve conduction measurement based on lumbosacral evoked potentials]. 238 Oct 78


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