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

Penfield proposed that the meningocerebral scar that forms following trauma to the brain plays an important role in the development of posttraumatic epilepsy. Although the epileptogenic scar has come to be widely accepted as a cause of epilepsy, there is no direct evidence that scar formation contributes to epileptogenesis. This current study showed that procedures that control the development of collagen in a fibroblastic scar may modify the development of epilepsy. Epilepsy induced in the guinea pig by injection of metallic aluminum powder into the cerebral cortex was used as a model of posttraumatic epilepsy. Following application of aluminum and implantation of epidural electrodes, animals received either daily injections of prednisolone or an ascorbic acid-deficient diet to block scar formation. Control animals also had an injection of aluminum, but afterward received saline injections or a normal diet. Control animals developed epileptic spikes and often exhibited focal seizures. All manifestations of epileptogenesis were markedly reduced in animals treated with prednisolone or the ascorbic acid-deficient diet. The reduction in epileptiform activity corresponded to reduced collagenous scar formation in the treated animals. Although effective when given prophylactically, prednisolone did not inhibit the activity of an already established epileptic focus whether induced by aluminum or by amygdala kindling, nor did it block pentylenetetrazol-induced seizures. The finding that epileptogenesis is blocked by two procedures that inhibit scar formation but show no evidence of a direct anticonvulsant effect, suggests that scar formation is a significant factor in epileptogenesis induced by metallic aluminum. The collagenous component appears to be more significant than the glial component of the scar.
 ...
PMID:Control of scar formation in experimentally induced epilepsy. 378 Sep 5

An 8 1/2-year-old girl presented with a long history of seizures, growth retardation, muscle weakness, gait disturbance, and hearing loss. Her evaluation revealed chronic moderate renal failure (serum creatinine 2.2 mg/dL), severe hypocalcemia (5 mg/dL), hyperphosphatemia (8.1 mg/dL), hypomagnesemia (1.5 mg/dL), increased urinary magnesium excretion (2 mg/kg/d), high fractional excretion of magnesium (21.7%), hypokalemia (3.2 mEq/L), and hyperkaliuria (26 mEq/L). Low circulating immunoreactive parathyroid hormone levels for the degree of the hypocalcemia (serum N-parathyroid hormone 212 pg/mL) and severe rickets without evidence of osteitis fibrosa cystica were found. The patient probably has primary renal leak hypomagnesemia (magnesuric hypomagnesemia) which caused impaired secretion of immunoreactive parathyroid hormone leading to severe hypocalcemia and calcium deficiency rickets. Treatment with magnesium and calcium supplements, calcitriol, and aluminum hydroxide resulted in marked clinical, biochemical, and radiologic improvement. Calcium deficiency rickets due to primary or secondary renal magnesium wasting in conjunction with moderate renal failure represents a largely unrecognized metabolic bone disease.
 ...
PMID:Severe renal osteodystrophy without elevated serum immunoreactive parathyroid hormone concentrations in hypomagnesemia due to renal magnesium wasting. 382 40

Similar patterns of neurotoxicity were produced in rabbits receiving 20 to 28 subcutaneous (sc) 400 mumol/kg injections of aluminum (Al) lactate given during 1 month and in rabbits receiving a single 2.5 to 5 mumol Al injection into each cerebral ventricle (icv). Predominant overt features of the Al-induced encephalopathy included splayed limbs, seizures and postural changes. Elevated brain Al concentrations, especially in cortical regions, were associated with behavioral changes and the development of neurofibrillary tangles (NFTs). In rabbits developing NFTs, an Al concentration of 3.5 micrograms/gm dry weight was the minimal concentration associated with tangle formation. However, no correlation was seen between brain Al concentration and the number of NFTs produced. Elevated brain Al concentrations and symptoms of Al-induced encephalopathy were seen approximately 12 days after icv and 18 days after completion of sc Al injections. The results from the present study demonstrate that the neuropathology, brain aluminum concentrations, and behavioral symptomatology produced by centrally administered Al can be replicated by administration of an adequate dose of peripherally administered Al. Furthermore, an advantage of peripheral Al administration over icv Al administration is that a longer period of time is seen between dosing and the full onset of the encephalopathy, providing more time to study the effects of Al intoxication.
 ...
PMID:Comparative toxicity of intracerebroventricular and subcutaneous aluminum in the rabbit. 404 17

Epileptic and normal Macaca mulatta monkey cortex was investigated using ligand binding techniques. Subpial injections of aluminum hydroxide gel into the left sensorimotor cortex produced stable seizure frequencies over a two year period and resulted in specific biochemical and receptor abnormalities. Pair matched CSF samples comparing epileptic and non-epileptic hemispheres showed a significant decreased GABA concentration over the epileptic side. The epileptic cortex demonstrated markedly reduced GABA receptor binding and diminished tissue GABA concentration and GAD activity. Two patterns of receptor loss were observed: nonspecific local cellular drop out involving multiple neurotransmitter receptors; and distal receptor loss which was specific for the neurotransmitter intervention pattern of the cortex. GABAergic receptor loss was more marked than receptor losses for the other neurotransmitter and was more widespread. Scatchard plot analysis demonstrated that the diminished GABAergic receptors within the focus were due to receptor loss and not affinity changes. Spearman rank correlations showed a significant correlation only between the degree of GABAergic receptor loss or decrease in GAD activity and the seizure frequency. Epilepsy appears to be a multifactoral disorder with multiple neuroreceptor abnormalities, the most notable of which are the destruction of GABAergic neurons and GABA receptors.
 ...
PMID:Neurotransmitter, receptor and biochemical changes in monkey cortical epileptic foci. 611 78

The authors present the results of medical examinations of 444 workers from an aluminum electrolysis plants with occupational exposure to fluorides, polycyclic aromatic hydrocarbons, carbon dioxide, aluminum dust and electromagnetic fields. The concentration of fluorides and polycyclic aromatic hydrocarbons exceeded the accepted levels. Nervous system changes, probably caused by occupational harmful factors, were demonstrated in 123 workers, with neurotic syndromes in 89. Slight pyramidal and cerebellar changes were observed in the remaining 39 workers. In 71 cases EEG investigations were done and 10 were abnormal, including 9 with seizure activity, and one with diffuse changes. The authors stress great difficulties in evaluating the combined action of toxic and physical factors on the nervous system.
 ...
PMID:[Evaluation of the combined effect of various harmful physical and chemical factors on the nervous system]. 641 Feb 97

A new method for producing electro-clinical correlates of absence seizures (petit mal epilepsy) in conscious juvenile rhesus monkeys is described. A behavioral arrest reaction associated with concomitant 2 1/2 to 3 Hz spike and wave electroencephalograph (EEG) after discharge pattern, was obtained by thalamic stimulation in monkeys with bilaterally symmetric aluminum hydroxide (Al(OH)3) lesions in anterior premotor cortical areas. The characteristic behavioral and EEG features associated with absence seizures appeared reproducibly, 63 +/- 5 days after aluminum hydroxide cortical implantation. This test system distinguishes between anticonvulsants that are effective in generalized seizures of the absence type and anticonvulsant drugs that are effective in focal seizures. Clinically useful anti-absence drugs, such as ethosuximide, sodium valproate, clonazepam, and trimethadione, are effective in this model. Diphenylhydantoin, which is contraindicated in absence states, increases the spike and wave after-discharge pattern. The limitations, advantages, and potential usefulness of this model in predicting anti-absence activity as well as the incidence of side effects of new drugs is discussed.
 ...
PMID:Behavioral and electrical correlates of absence seizures induced by thalamic stimulation in juvenile rhesus monkeys with frontal aluminum hydroxide implants: a pharmacologic evaluation. 681 26

A child with renal insufficiency was treated with the oral phosphate binder aluminum hydroxide from age 6 to 31 months. The prescribed dose of elemental aluminum varied from 31 to 108 mg/kg/d. Concurrently the patient developed vitamin D-resistant osteomalacia which failed to improve with parathyroidectomy. Encephalopathy with myoclonic seizures, loss of speech, and motor impairment also occurred. Serum and bone aluminum levels were elevated at 334 micrograms/L (normal 7 +/- 3 micrograms/L) and 156 mg/kg (normal 3.3 +/- 2.9 mg/kg), respectively. This case demonstrates that aluminum may accumulate in tissue of children receiving oral aluminum hydroxide. The accumulation of aluminum may have contributed to the vitamin D-resistant osteomalacia and the encephalopathy in this patient. Children receiving aluminum-containing antacids as phosphate binders should be monitored for aluminum accumulation and signs of aluminum intoxication.
 ...
PMID:Accumulation of aluminum in a nondialyzed uremic child receiving aluminum hydroxide. 684 80

A retrospective analysis of children with renal failure during the first year of life revealed that 20 of 23 patients developed profound neurologic abnormalities. The encephalopathy was characterized by developmental delay, microcephaly, hypotonia, seizures, dyskinesia, and EEG abnormalities. No patient had been dialyzed, and four had not received aluminum salts prior to the development of neurologic symptoms. Inadequate statural growth and poor nutrition were present in all patients. It is probable that infants with chronic renal insufficiency are more susceptible to the development of this syndrome than are older children or adults because of the significant growth and maturation of the brain that occurs during the first years of life.
 ...
PMID:Progressive encephalopathy in children with chronic renal insufficiency in infancy. 708 84

A slurry of aluminum powder injected into the brains of mature rabbits produced neurofibrillary changes in neurons of spinal cord and cerebrum similar to those produced by aluminum chloride, and with similar topography and rates of formation. The major difference observed with this preparation was that many rabbits survived several weeks or months before having any obvious seizures, compared to 2 to 3 weeks with aluminum chloride, and some survived with no obvious symptoms, apparently indefinitely (12 months being the longest time before sacrifice). This chronic animal model of neurofibrillary changes, induced in a mature nervous system, will allow better investigations of alterations in the biochemistry, pathology, behavior and cognition which may occur.
 ...
PMID:Chronic model of neurofibrillary changes induced in mature rabbits by metallic aluminum. 709 62

Cortical surface electrodes and bipolar depth electrodes were implanted stereotaxically in the ventral posterolateral and paracentral thalamic nuclei, amygdala, hippocampus, and putamen in adult cats to determine the progressive involvement of these structures in the generalization of an experimentally induced seizure disorder. Prior to (45-65 days) and following (50-70 days) subpial injection of 0.04 ml of aluminum hydroxide in the sensorimotor cortex, 30 min EEG records were obtained regularly in each animal. At the time of aluminum hydroxide injection, there was no persistent abnormal EEG activity resulting from electrode implantation. In all animals, intermittent slow waves and epileptiform activity appeared in subcortical or extrafocal structures prior to the development of epileptiform activity in the primary focus. These abnormalities were frequently associated with brief clinical seizures and were clearly independent of abnormal activity in the primary focus. Only later in the development of the seizure disorder was activity in the secondary foci observed to be dependent on frequent epileptiform activity in the primary focus. These results demonstrate that multiple, independent foci develop in subcortical structures before the occurrence of a well developed, fully "mature" cortical primary focus.
 ...
PMID:The early involvement of subcortical structures during the development of a cortical seizure focus. 717 25


<< Previous 1 2 3 4 5 6 7 Next >>