ABSTRACT
Continuous video-electroencephalography (EEG) is an important diagnostic and prognostic tool in newborns with hypoxic-ischemic encephalopathy undergoing therapeutic hypothermia. The optimal duration of continuous video-EEG during whole-body hypothermia is not known. We conducted a retrospective study of 35 neonates with hypoxic-ischemic encephalopathy undergoing whole-body hypothermia with continuous video-EEG. EEG ictal changes were detected in 9/35 infants (26%). Of these 9 infants, the seizures were initially observed within 30 minutes of EEG monitoring in 6 (67%), within 24 hours in 2 (22%), and during rewarming in 1 infant (11%). No new seizures were detected between 24-72 hours of therapeutic hypothermia. Background suppression was detected in 14 infants (40%) by 24 hours. In neonates with hypoxic-ischemic encephalopathy undergoing therapeutic hypothermia, continuous video-EEG has the highest diagnostic yield within the first 24 hours and during the rewarming phase. In the absence of prior seizures or antiepileptic therapy, limiting continuous video-EEG to these periods in resource-limited settings may reduce cost during therapeutic hypothermia.
Subject(s)
Brain Waves/physiology , Electroencephalography/methods , Hypothermia, Induced/methods , Hypoxia-Ischemia, Brain/physiopathology , Hypoxia-Ischemia, Brain/therapy , Video Recording , Child , Child, Preschool , Female , Humans , Hypoxia-Ischemia, Brain/diagnostic imaging , Image Processing, Computer-Assisted , Intensive Care Units, Neonatal , Magnetic Resonance Imaging , Male , Neuropsychological Tests , Retrospective Studies , Seizures/diagnostic imaging , Seizures/etiology , Severity of Illness IndexABSTRACT
Glutamate receptor currents were examined in horizontal cells from cultured human retina using whole-cell recording procedures. Horizontal cells possess both AMPA and kainate receptors and both produce significant sustained currents. The kainate-induced current did not show significant desensitization and was not enhanced by concanavalin A. The sustained AMPA current was smaller than the kainate current, but the difference was almost entirely due to pronounced desensitization. The horizontal cell AMPA current was enhanced by cyclothiazide but not by PEPA, indicating the presence of the flip receptor variant. GYKI-52466 blocked the AMPA response (IC50 = 5 microM against 100 microM AMPA) but also blocked the kainate response (IC50 = 45 microM against 100 microM kainate). The diversity of glutamate receptors in human horizontal cells suggests that synaptic input to these neurons may be multiplexed through both kainate and AMPA channels.
