• Annals of Clinical Neurophysiology
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• v.16 no.1
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• pp.15-20
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• 2014

Background: Triphasic waves are one of the electroencephalographic patterns that can be usually seen in metabolic encephalopathy. The aim of this study is to compare the clinical and electrophysiologic profiles between patients with and without triphasic waves in metabolic encephalopathy, and reassess the significance of triphasic waves in metabolic encephalopathy. Methods: We recruited 127 patients with metabolic encephalopathy, who were admitted to our hospital. We divided these admitted patients into two groups; those with and without triphasic waves. We analyzed the difference of duration of hospitalization, mortality rate during admission, Glasgow Coma Scale, severity of electroencephalographic alteration, and presence of acute symptomatic seizures between these two groups. Results: Of the 127 patients with metabolic encephalopathy, we excluded 67 patients who did not have EEG, and 60 patients finally met the inclusion criteria for this study. Patients with triphasic waves had more severe electroencephalographic alterations, lower Glasgow Coma Scale, and more acute symptomatic seizures than those without triphasic waves. After adjusting the clinical variables, Glasgow Coma Scale and acute symptomatic seizures were only significantly different between patients with and without triphasic waves. Conclusions: We demonstrated that patients with triphasic waves in metabolic encephalopathy had more significant impairment of the brain function.

• Annals of Clinical Neurophysiology
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• v.9 no.2
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• pp.63-68
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• 2007

The EEG plays an important diagnostic role in epilepsy and provides supporting evidence of a seizure disorder as well as assisting with classification of seizures and epilepsy syndromes. There are a variety of electroclinical syndromes that are really defined by the EEG such as Lennox-Gastaut syndrome, benign rolandic epilepsy, childhood absence epilepsy, juvenile myoclonic epilepsy and also for localization purposes, it is vitally important especially for temporal lobe epilepsy. The sensitivity of first routine EEG in diagnosis of epilepsy has been known about 20-50%, but this proportion rises to 80-90% if sleep EEG and repetitive recording should be added. Convincing evidences suggest that the EEG may also provide useful prognostic information regarding seizure recurrence after a single unprovoked attack and following antiepileptic drug (AED) withdrawal. Moreover, patterns in the EEG make it possible to disclose an ictal feature of nonconvulsive status epilepticus, separate epileptic from other non-epileptic episodes and clarify the clues predictive of the cause of the encephalopathy (i.e., triphasic waves in metabolic encephalopathy). Therefore, regardless of its low sensitivity and other pitfalls, EEG should be considered not only in the situation of new onset episode such as a newly developed, unprovoked seizure or a condition manifesting decreased mentality from obscure origin, but also as a barometer of the long-term outcome following AED withdrawal.

• The Korean Journal of Physiology
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• v.29 no.2
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• pp.233-241
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• 1995

The nonapeptide bradykinin has been shown to exhibit an array of biological activities including relaxation/contraction of various smooth muscles. In order to investigate the effects of bradykinin on the contractility and the electrical activity of antral circular muscle of guinea-pig stomach, the isometric contraction and membrane potential were recorded. Also, using standard patch clamp technique, the $Ca^{2+}-activated$ K currents were recorded to observe the change in cytosolic $Ca^{2+}$ concentration. $0.4 {\mu}M$ bradykinin induced a triphasic contractile response (transient contraction-transient relaxation-sustained contraction) and this response was unaffected by pretreatment with neural blockers (tetrodotoxin, atropine and guanethidine) or with apamin. Bradykinin induced hyperpolarization of resting membrane potential and enhanced the amplitude of slow waves and spike potentials. The enhancement of spike potentials was blocked by neural blockers. Both the bradykinin-induced contractions and changes in membrane potential were reversed by the selective $B_2$-receptor antagonist $(N{\alpha}-adamantaneacetyl-_{D}-Arg-[Hyp, Thy,_{D}-Phe]-bradykinin)$. In whole-cell patch clamp experiment, we held the membrane potential at -20 mV and spontaneous and transient changes of Ca-activated K currents were recorded. Bradykinin induced a large transient outward current, consistent with a calcium-releasing action of bradykinin front the intracellular calcium pool, because such change was blocked by pretreatment with caffeine. Bradykinin-induced contraction was also blocked by pretreatment with caffeine. From these results, it is suggested that bradykinin induces a calciumrelease and contraction through the $B_{2}$ receptor of guinea-pig gastric smooth muscle. Enhancement of slow wave activity is an indirect action of bradykinin through enteric nerve cells embedded in muscle strip.