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Query: UMLS:C0036572 (seizures)
 80,221 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of morphine and naloxone on acute cocaine toxicity was studied. Male Sprague-Dawley rats were pretreated intraperitoneally (ip) with saline, morphine sulfate 25 mg/kg, or naloxone 1.0 mg/kg 15 minutes prior to challenge by cocaine. After pretreatment, each group was challenged with one of three doses of cocaine (35, 50, or 75 mg/kg ip). Each of the nine drug combinations was tested on at least 10 animals. Animals were observed for behavior, seizures, and death. The animals pretreated with saline and challenged with cocaine (35, 50, or 75 mg/kg) had seizure incidences of 0%, 40%, and 100%, respectively, after increasing doses. Pretreatment with morphine resulted in cocaine-induced seizures of 20%, 80% and 100%, respectively (p less than or equal to 0.05 with cocaine 35 and 50 mg/kg). Time to seizures in these groups did not differ significantly compared to the saline groups. Pretreatment with naloxone resulted in cocaine-induced seizures of 0%, 50%, and 60% (p less than or equal to 0.05 at the 75 mg/kg dose). The incidence of death was significantly increased by pretreatment with morphine in animals that received cocaine 50 or 75 mg/kg. The time to death was not significantly different compared to saline controls. The death rate in naloxone pretreated animals was not significantly different from the saline groups. In additional studies, high-dose naloxone pretreatment (10 mg/kg) also failed to provide protection from acute cocaine toxicity. In conclusion, cocaine toxicity is potentiated by morphine and does not appear to be altered by naloxone.
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PMID:The effect of morphine and naloxone on cocaine toxicity. 159 78

The characteristics and treatment of preeclampsia and eclampsia are reviewed. Risk factors for preeclampsia include (1) nulliparity, (2) a mother or sister(s) with a history of the disorder, (3) essential hypertension or renal disease, or (4) a twin or molar pregnancy. Preeclampsia is diagnosed when the systolic blood pressure (BP) increases by 30 mm Hg or the diastolic BP increases by 15 mm Hg after the 20th week of gestation and the BP rise is accompanied by edema, proteinuria, or both. Severe preeclampsia is diagnosed when the BP reaches or exceeds 160 mm Hg systolic or 110 mm Hg diastolic after bed rest. Eclampsia is the occurrence of seizures (in the preeclamptic patient) that cannot be attributed to other causes; it occurs in about 0.2% of preeclamptic patients. Magnesium sulfate (in the injectable, hydrated form) is the agent used most often for seizure prophylaxis in the preeclamptic patient in the United States. It is also used widely to control seizures once they develop. In the United States, diazepam is used to supplement magnesium sulfate if necessary to control seizures, but its use is not routine. Among antihypertensive agents, i.v. hydralazine is preferred in this country to control blood pressure in the severely preeclamptic or eclamptic patient. Several studies provide promising evidence that low-dose aspirin (60-150 mg daily beginning at 28-30 weeks of gestation) prevents preeclampsia in women who are at risk for its development. Until additional comparative studies are completed, magnesium sulfate and hydralazine will remain the standard of care for the treatment of preeclampsia in the United States.
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PMID:Treatment of preeclampsia and eclampsia. 161 13

Treatment of this pathophysiologically poorly understood disease is controversial. Despite this uncertainty, the goals of management of the patient with preeclampsia and eclampsia are diagnosis, stabilization, and delivery of the baby. Stabilization refers to both mother and fetus and should include the prevention of eclampsia or the recurrence of eclamptic seizures. There are empiric data supporting the use of magnesium sulfate for the management of preeclampsia and eclampsia in North America, but there are few data to support its efficacy as a classic anticonvulsant. Until controlled trials are completed, we suggest that magnesium sulfate continue to be used in preeclampsia, with the addition of established anticonvulsant medications when eclampsia occurs. Data on established antiepileptic drugs such as diazepam and phenytoin support their use in treating patients with eclamptic seizures. As stated in an earlier review, "in treating preeclampsia, magnesium sulfate therapy may have a role and may moderate factors leading to eclampsia. Whether magnesium sulfate therapy may have some as yet unproved effect on epileptogenic foci or seizure propagation is not the important issue for the physician caring for the eclamptic patient. Until adequately designed therapeutic trials are available, it is our opinion that treatment should be based on the use of anticonvulsant drugs of established efficacy in seizure control and prophylaxis (p. 1363)."
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PMID:Prophylaxis of eclamptic seizures: current controversies. 163 27

The GABAA receptor has been implicated in the mechanisms underlying the phenomenon of kindling. Photoaffinity labeling with 3H-flunitrazepam followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis allows the fluorographic visualization of GABAA receptor proteins with benzodiazepine binding sites which presumably correspond to different alpha-subtypes. This method offers an opportunity to investigate whether up- or down-regulation of single benzodiazepine binding proteins occurs. In the present study, labeling patterns of benzodiazepine binding proteins were determined in 12 brains regions of amygdala-kindled rats (2 weeks after the last fully kindled seizure) and sham-operated controls. For most brain regions, labeling patterns were separately determined for the ipsi- and contralateral side. A comparison of the labeling patterns thus obtained revealed no persistent changes between kindled animals and controls in any of the brain regions, including amygdala, substantia nigra and hippocampus. Thus, we conclude that kindling does not induce fluorographically detectable changes in the expression patterns of the benzodiazepine binding proteins. The results confirm the existence of regional heterogeneity of benzodiazepine binding proteins and extend the findings to brain regions which had previously not been investigated.
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PMID:Kindling does not induce persistent changes in fluorographic labeling patterns of benzodiazepine binding proteins in various rat brain regions. 166 15

We describe the clinical, pathological, ultrastructural and biochemical features in the case of a 15-year-old boy with multiple sulfatase deficiency. Clinical abnormalities included hypotonia, retarded psychomotor development, hepatosplenomegaly, pigmentary degeneration of the retina, myoclonic seizures, aortic insufficiency and quadriplegia. Urinalysis revealed increased heparan sulfate. At necropsy, aortic and mitral valves revealed nodular thickening and periodic acid-Schiff (PAS)-positive, metachromatic granules in renal proximal tubules. The brain weighed 400 g and demonstrated cerebral and cerebellar atrophy with a retrocerebellar meningeal cyst. Cortical neurons contained periodic acid-Schiff-positive and cresyl violet-reactive granules. White matter demonstrated brown metachromasia and intense fibrillary gliosis. Conjunctival fibroblasts contained amorphous vacuoles with dense osmiophilic nucleoid cores. Pleomorphic extracellular, intraneural and intraglial inclusions were noted in the brain. Activities of arylsulfatase A, B and C were diminished markedly in autopsied tissue from brain, liver, and kidney (0, 0 and less than 10% of control activities, respectively). Partial deficiencies of iduronate sulfatase and heparan sulfatase were noted in different tissues. Variable decreased enzyme activities were expressed in leukocytes: arylsulfatase A, less than 33%; B, 40%; and C, 90%; heparan sulfatase, 2%; and iduronate sulfatase was not detectable. Near normal activities were found in cultured fibroblasts.
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PMID:Multiple sulfatase deficiency: clinical, neuropathological, ultrastructural and biochemical studies. 169 40

Male Sprague-Dawley rats injected sc with a single sublethal dose of the organophosphate nerve agent, soman (100 micrograms/kg), had motor limbic seizures within 5-15 min. Pretreatment with a single dose of memantine HCl (MEM, 18 mg/kg, sc), alone or in combination with atropine sulfate (ATS, 16 mg/kg, sc), before soman prevented seizures without sedation or ataxia. Rats appeared normal or demonstrated increased exploratory activity. Excessive salivation, a peripheral manifestation of soman intoxication, was decreased by ATS, but pretreatment with ATS alone did not prevent seizures. After seizure onset, MEM +/- ATS, but not ATS, abolished seizures. Acetylcholinesterase (AChE) activity in several brain regions (cortex, stem, striatum, and hippocampus) was markedly reduced by soman, but not by MEM, ATS, or MEM + ATS. Preadministration of MEM + ATS in vivo significantly protected AChE from inhibition by soman. Memantine reduced inhibition of AChE activity in crude brain homogenates by soman, but not by edrophonium (anionic site inhibitor) or decamethonium (peripheral site inhibitor). Thus, MEM may bind to a different modulatory site, not yet characterized, to protect AChE. When given after onset of soman-induced seizures, treatment with MEM +/- ATS did not reactivate AChE although seizures were controlled, suggesting additional anticonvulsant mechanisms of action. At concentrations (10(-4) to 5 x 10(-4) M) which did not significantly alter the spontaneous firing of action potentials (APs), MEM limited sustained high frequency repetitive firing (SRF) induced by depolarization of spinal cord (mouse and rat) and neocortical (mouse) neurons in monolayer-dissociated cell culture. In the same range of concentrations, ATS both limited SRF and suppressed spontaneous activity, suggesting toxicity. In addition, MEM and ATS reversibly produced use-dependent block of depolarizing responses to acetylcholine (ACh) applied by pressure ejection to spinal cord neurons. Thus, the anticonvulsant efficacy of MEM, with or without ATS, may have resulted from a combination of actions, including protection of AChE from inhibition by soman, limitation of high frequency firing of APs, and blockade of excitatory postsynaptic responses to ACh.
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PMID:Prophylactic and therapeutic efficacy of memantine against seizures produced by soman in the rat. 173 53

The use of magnesium sulfate (MgSO4) as an anticonvulsant is controversial. Status epilepticus was induced in 0.5% halothane-anesthetized Wistar rats with a threshold (90 mg/kg) or suprathreshold (200 mg/kg) dose of intravenous (i.v.) pentylenetetrazol (PTZ) under stereotactic hippocampal depth electrode monitoring. Fifteen minutes after seizure induction, the maximum hemodynamically tolerated dose of MgSO4 (10 mg/kg/min in 22 min) was administered i.v. MgSO4 was ineffective in altering seizure discharge. A subgroup of nine animals received hypertonic mannitol before MgSO4 to open the blood-brain barrier (BBB) to facilitate Mg2+ CNS penetration. Again MgSO4 was ineffective in attenuating epileptic activity. These results support the contention that MgSO4 is not an effective treatment for status epilepticus. We hypothesize that because Mg2+ blocks Ca2+ influx into the neuron through the N-methyl-D-aspartate (NMDA) receptor-operated calcium channel in a voltage-dependent manner it would be ineffective in neurons that are continuously depolarizing as in status epilepticus.
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PMID:Effects of magnesium sulfate on pentylenetetrazol-induced status epilepticus. 183 Nov 20

We report a 16-year-old girl with acute intermittent porphyria who had abdominal pain, generalized tonic-clonic and simple partial seizures, and inappropriate antidiuretic hormone secretion. Because most antiepileptic drugs are contraindicated in porphyria, she was treated with magnesium sulfate i.v. Soon after starting treatment, seizures stopped, returned, and then again responded in several trials with discontinuation and reinstitution of i.v. magnesium sulfate. Our experience encourages the use of magnesium sulfate for treatment of seizures in patients with porphyria.
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PMID:Treatment of porphyric convulsions with magnesium sulfate. 191 81

Seizure prophylaxis is standard intrapartum therapy for patients with pregnancy-induced hypertension. Magnesium sulfate is used in the United States in spite of limited literature comparing its efficacy with other anticonvulsants. Fifty patients with pregnancy-induced hypertension were prospectively randomized to receive magnesium sulfate or phenytoin for seizure prophylaxis. Patients were observed for toxicity, side effects, and labor outcomes, and the neonates were evaluated for side effects of the therapy. Three patients were excluded with adverse reactions to medications (one in magnesium sulfate group, two in phenytoin group). No differences were found in patient tolerance, adverse reactions, or neonatal outcomes between groups. Maternal free phenytoin levels were 13.0% +/- 0.4% of total phenytoin (serum albumin, 2.5 to 3.5 gm/dl), significantly higher than in nonpregnant patients. Neither free phenytoin levels nor percentage of total phenytoin that was free correlated significantly with maternal albumin levels. The pharmacokinetics of phenytoin loading in the massively obese pregnant patient may differ and require further evaluation. Phenytoin is a well-tolerated alternative to magnesium sulfate for seizure prophylaxis in the patient with mild pregnancy-induced hypertension.
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PMID:Magnesium sulfate versus phenytoin for seizure prophylaxis in pregnancy-induced hypertension. 195 52

Seizures in pregnancy pose risks for both the mother and the fetus and must be managed aggressively. Antiepileptic drugs have some teratogenic potential, but the risks are not as profound as reported in earlier literature. There is definitely less risk to the fetus from anticonvulsant exposure than from uncontrolled seizures. The evaluation of a pregnant woman with new-onset seizures is the same as for the nonpregnant patient, including head computed tomography with appropriate abdominal shielding. Status epilepticus management is based on IV benzodiazepines, phenytoin, or phenobarbital. Good fetal outcome is dependent on rapid seizure control. Management of eclampsia is controversial. There is little evidence that magnesium sulfate has anticonvulsant properties, and its use as such will probably decline steadily in the future. At present, it is reasonable to manage eclamptic seizures in the same way that status epilepticus is managed.
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PMID:Emergency department approach to managing seizures in pregnancy. 195 21


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