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

Recurrent heritable childhood myoglobinuria is a potentially fatal entity (mortality up to 35%) in which prompt diagnosis and treatment are critical. Sixty childhood cases have been reported between 1910 to 1988, most with undiagnosed etiologies. We have studied an additional 40 cases referred to CPMC (1980-1988), suggesting that this condition is largely underdiagnosed or unreported. We have found important differences between the childhood and adult-onset cases. Of 77 cases of adult-onset recurrent myoglobinuria, 45% have been diagnosed biochemically. In contrast, only 30% of the 60 childhood cases from the literature have been diagnosed; 11 with CPT deficiency and 7 with various glycolytic defects, and only 5 of our 40 childhood cases have been diagnosed, all with CPT deficiency. The 100 combined childhood cases can be divided into an exertional group (type I) with exertion as the leading precipitating factor (46 literature and 10 CPMC cases), a toxic group (type II) with infection and/or fever as the primary precipitant (14 literature and 23 CPMC cases), and 7 undefined cases. The type I group resembles the adult-onset group in which exercise is also the leading precipitating factor. There is a slight female predominance (male/female = 1:1.3) in the toxic group vs. a marked male predominance in the exertional and adult groups (4:1). Only 4 of 37 cases (11%) of the toxic group are diagnosed (all with CPT deficiency) vs. 19 of 56 cases (34%) of the exertional group (12 CPT, 7 glycolytic) and 45% of the adult group. The toxic group is also differentiated by a higher mortality rate and by the presence of additional clinical features, including ictal bulbar signs (8 of 18), encephalopathy (4 of 19), and seizures (2 of 7), as well as persistent cardiac abnormalities, developmental delay (4 of 17), and dysmorphic features (2 of 9). These clinical characteristics clearly differentiate the childhood from the adult cases and suggest the presence of more generalized disease processes and different biochemical etiologies. A study of the heritable causes of myoglobinuria is important because identification of the biochemical defect may elucidate the pathogenetic mechanism of the myoglobinuria and facilitate the development of rational treatment strategies aimed at circumventing or correcting the metabolic block.
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PMID:Recurrent childhood myoglobinuria. 226 36

We tested the effects of 8-cyclopentyl-1,3 dimethylxanthine (8-CPT) on electrically induced seizures in rats. 8-CPT prolonged secondary seizures and converted partial seizures into generalized motor seizures, but did not affect primary seizure duration. Because 8-CPT is a potent and specific adenosine antagonist, these results add further support to the hypothesis that endogenous adenosine prevents the spread of epileptic seizures.
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PMID:8-Cyclopentyl 1,3-dimethylxanthine prolongs epileptic seizures in rats. 365 21

The effect of a selective adenosine antagonist, 8-cyclopentyl 1,3-dimethylxanthine (8-CPT) was used to examine involvement of adenosine in ictal and postictal events in rats subjected to maximal electroshock (MES). MES induces the ictal event of hindlimb tonic extension (HLTE) followed by postictal depression (PID). 8-CPT 10 mg/kg, ip produced maximal significant reduction of PID without affecting HLTE, further confirming involvement of adenosine in PID. Carbamazepine and sodium valproate were studied independently and were coadministered with 8-CPT to determine if their anticonvulsant activity was modulated by adenosine and if they altered PID. 8-CPT did not antagonize the seizure protection afforded by CBZ or SV. CBZ significantly reduced postictal events whereas SV had no significant effect. These observations further confirm a role for adenosine in postictal phenomena.
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PMID:Involvement of adenosine in postictal events in rats given electroshock. 813 42

Effects of the cyclic AMP agonists 8-(4-chlorophenylthio)-adenosine 3':5' cyclic monophosphate (CPT-cAMP), dibutyryl cyclic AMP (dbcAMP) and forskolin were studied on extracellular field potentials in rat neocortex slices in vitro. CPT-cAMP and forskolin produced a prolonged enhancement of epileptiform activity resulting from removal of Mg2+ from the bathing medium. DbcAMP had no apparent effect except at high concentrations (1 mM), when it reduced bursting activity. Field potentials observed following electrical stimulation of the corpus callosum in the presence of Mg2+ were enhanced by CPT-cAMP and dbcAMP; however forskolin was without effect. Intracellular recording techniques demonstrated a transient excitatory influence of dbcAMP. The results indicate a role for cyclic AMP in seizure mechanisms.
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PMID:Cyclic AMP analogues increase excitability and enhance epileptiform activity in rat neocortex in vitro. 839 51

We describe the term male infant of asymptomatic, healthy nonconsanguineous parents presenting on the first day of life with nonketotic hypoglycemia, seizures, hepatomegaly, cardiomegaly with biventricular hypertrophy, and ventricular arrhythmias. Cranial ultrasound revealed cystic dysplasia with several foci of hyperechogenicity within the right basal ganglia. Free carnitine was markedly decreased in the urine and plasma with a pronounced elevation of plasma long-chain acylcarnitines. Fibroblast carnitine palmitoyltransferase II activity was reduced to 26% and 38% in the father and mother, respectively. The infant expired on day 5 of life from malignant ventricular tachy-arrhythmias. Diffuse lipid accumulation was evident at autopsy, including in the liver, heart, kidney, adrenal cortex, skeletal muscle, and lungs. This new case of infantile CPT-II deficiency illustrates the severity of the early onset form of CPT-II deficiency.
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PMID:Fatal carnitine palmitoyltransferase II deficiency in a newborn: new phenotypic features. 992 37

In this study the role of adenosine A1 and A2A receptors of the hippocampal CA1 region on piriform cortex-kindled seizures was investigated in rats. Animals were kindled by daily electrical stimulation of piriform cortex. In fully kindled rats, N6-cyclohexyladenosine (CHA; a selective A1 receptor agonist), 1,3-dimethyl-8-cyclopenthylxanthine (CPT; a selective A1 receptor antagonist), CGS21680 hydrochloride (CGS, a selective A2A receptor agonist) and, ZM241385 (ZM, a selective A2A receptor antagonist) were microinfused bilaterally into the hippocampal CA1 region. Rats were stimulated and seizure parameters were measured. Obtained results showed that microinjection of CHA (10 and 100 microM) decreased the afterdischarge duration (ADD), stage 5 seizure duration (S5D) and seizure duration (SD), and significantly increased the latency to stage 4 (S4L). Intra-hippocampal CPT increased ADD at the dose of 20 microM. Pretreatment of rats with CPT (10 microM) before CHA (10 microM), significantly reduced the effect of CHA on seizure parameters. On the other hand, microinjection of CGS (200 and 500 microM) increased ADD, but of ZM had no effect on seizure parameters. Pretreatment of rats with ZM (50 microM) before CGS (500 microM), significantly reduced the effect of CGS on seizure parameters. The results suggest that the facilitatory role of the hippocampal CA1 region in relaying or spreading of piriform cortex kindled seizures is decreased by the activation of adenosine A1 receptors and increased by A2A receptors.
Seizure 2006 Jan
PMID:Adenosine A1 and A2A receptors of hippocampal CA1 region have opposite effects on piriform cortex kindled seizures in rats. 1633 18

In this study, the role of adenosine A1 receptors of the hippocampal CA1 region in entorhinal cortex-kindled seizures was investigated in rats. Animals were kindled by daily electrical stimulation of the entorhinal cortex. In fully kindled rats, N(6)-cyclohexyladenosine (CHA; a selective A1 receptor agonist) and 1, 3-dimethyl-8-cyclopenthylxanthine (CPT; a selective A1 receptor antagonist) were microinfused bilaterally into the hippocampal CA1 region. Rats were stimulated and seizure parameters were measured. Results obtained showed that CHA (10 and 50 micro moles) decreased the afterdischarge duration (ADD) in the hippocampal CA1 region and entorhinal cortex, stage 5 seizure duration (S5D) and seizure duration (SD) only at the dose of 50 micro moles, and significantly increased the latency to stage 4 (S4L). Intrahippocampal CPT increased ADD and S5D, and significantly reduced the latency to stage 4 (S4L) at the dose of 10 micromoles. Pretreatment of rats with CPT (5 micro moles) before CHA (50 micro moles), significantly reduced the effect of CHA on seizure parameters. The results suggest that the CA1 region of the hippocampus plays an important role in spreading seizure spikes from the entorhinal cortex to other brain regions and activation of adenosine A1 receptors in this region participates in the anticonvulsant effects of adenosine agonists.
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PMID:Anticonvulsant effects of N6-cyclohexyladenosine microinjected into the CA1 region of the hippocampus on entorhinal cortex-kindled seizures in rats. 1715 Apr 38

In this study, the effect of A1 and A2A adenosine receptor activity of the piriform cortex (PC) on amygdala-kindled seizures was investigated in rats. Animals were kindled by daily electrical stimulation of the amygdala. In fully kindled rats, N6-cyclohexyladenosine (CHA, a selective A1 agonist), 8-cyclopentyl-1,3-dimethylxanthine (CPT, a selective A1 antagonist), CGS21,680 hydrochloride (CGS, a selective A2A agonist), and ZM241,385 (ZM, a selective A2A antagonist) were microinjected bilaterally into the PC. Rats were stimulated 5 min post-drug microinjection and seizure parameters were measured. Results showed that intra-PC CHA (10 and 100 micromol/L) decreased the duration of both afterdischarge and stage 5 seizure and significantly increased the latency to stage 4 seizure. Intra-PC CPT increased afterdischarge and stage 5 seizure duration at the dose of 20 micromol/L. The anticonvulsant effect of CHA (100 micromol/L) was eliminated by CPT (10 micromol/L) pretreatment. On the other hand, neither intra-PC CGS nor ZM had a significant effect on kindled seizures. These results suggest that activity of A1, but not A2A, receptors of the PC have anticonvulsant effects on kindled seizures elicited from electrical stimulation of the amygdala.
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PMID:Anticonvulsant effect of A1 but not A2A adenosine receptors of piriform cortex in amygdala-kindled rats. 1782 22

Adenosine is an endogenous inhibitor of excitatory synaptic transmission with potent anticonvulsant properties in the mammalian brain. Given adenosine's important role in modulating synaptic transmission, several mechanisms exist to regulate its extracellular availability. One of these is the intracellular enzyme adenosine kinase (ADK), which phosphorylates adenosine to AMP. We have investigated the role that ADK plays in regulating the presence and effects of extracellular adenosine in area CA1 of rat hippocampal slices. Inhibition of ADK activity with 5'-iodotubercidin (IODO; 5 muM) raised extracellular adenosine, as measured with adenosine biosensors, and potently inhibited field excitatory post-synaptic potentials (fEPSPs) in an adenosine A(1)R-dependent manner. In nominally Mg(2+)-free aCSF, which facilitated the induction of electrically-evoked epileptiform activity, adenosine biosensor recordings revealed that seizures were accompanied by the transient release of adenosine. Under these conditions, IODO also inhibited the fEPSP and greatly suppressed epileptiform activity evoked by brief, high-frequency stimulation. During spontaneous seizures evoked by the A(1)R antagonist CPT, adenosine release was unaffected by IODO. This suggests that ADK activity does not limit activity-dependent adenosine release. On the basis of strong ADK immunoreactivity in GFAP-positive cells, astrocytes are likely to play a key role in regulating basal adenosine levels. It is this action of ADK on the basal adenosine tone that is permissive to seizure activity, and, by extension, other forms of activity-dependent neuronal activity such as synaptic plasticity.
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PMID:Astrocytic adenosine kinase regulates basal synaptic adenosine levels and seizure activity but not activity-dependent adenosine release in the hippocampus. 1895 98

Low frequency stimulation (LFS) has an inhibitory effect on rapid perforant path kindling acquisition. In the present study the role of adenosine A(1) and A(2A) receptors in mediating this inhibitory effect was investigated. Rats were kindled by perforant path stimulation using rapid kindling procedures (12 stimulations per day). LFS (0.1 ms pulse duration at 1 Hz, 200 pulses, and 50-150 muA) was applied to the perforant path immediately after termination of each rapid kindling stimulation. 1,3-Dimethyl-8-cyclopenthylxanthine (CPT; 50 muM), a selective A(1) antagonist and ZM241385 (ZM, 200 muM), a selective A(2A) antagonist were daily microinjected into the lateral ventricle 5 min before kindling stimulations. LFS had an inhibitory effect on kindling development. Pretreatment of animals with CPT reduced the inhibitory effect of LFS on kindling rate and suppressed the effects of LFS on potentiation of population EPSP during kindling acquisition. In addition, CPT was able to antagonize the effects of LFS on kindling-induced increase in early (10-50 ms intervals) and late (300-1000 ms intervals) paired pulse depression. ZM pretreatment had no effect on antiepileptogenic effects of LFS in kindling acquisition. In addition, LFS prevented the kindling-induced elevation of cyclic AMP (cAMP) levels in kindled animals. Based on these results, we suggest that the antiepileptogenic effects of LFS on perforant path kindling might be mediated through activation of adenosine A(1), but not A(2A) receptors. Moreover, modulation of cAMP levels by LFS may potentially be an important mechanism which explains the anticonvulsant effects of LFS in kindled seizures.
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PMID:The role of adenosine A(1) receptors in mediating the inhibitory effects of low frequency stimulation of perforant path on kindling acquisition in rats. 1904 28


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