Previously, we reported that besides retinal ganglion cell (RGC) spike, there is ~ 10 Hz oscillatory rhythmic activity in local field potential (LFP) in retinal degeneration model, rd1 mice. The more recently identified rd10 mice have a later onset and slower rate of photoreceptor degeneration than the rd1 mice, providing more therapeutic potential. In this study, before adapting rd10 mice as a new animal model for our electrical stimulation study, we investigated electrical characteristics of rd10 mice. From the raw waveform of recording using 8x8 microelectrode array (MEA) from in vitro-whole mount retina, RGC spikes and LFP were isolated by using different filter setting. Fourier transform was performed for detection of frequency of bursting RGC spikes and oscillatory field potential (OFP). In rd1 mice, ~10 Hz rhythmic burst of spontaneous RGC spikes is always phase-locked with the OFP and this phase-locking property is preserved regardless of postnatal ages. However, in rd10 mice, there is a strong phase-locking tendency between the spectral peak of bursting RGC spikes (~5 Hz) and the first peak of OFP (~5 Hz) across different age groups. But this phase-locking property is not robust as in rd1 retina, but maintains for a few seconds. Since rd1 and rd10 retina show phase-locking property at different frequency (~10 Hz vs. ~5 Hz), we expect different response patterns to electrical stimulus between rd1 and rd10 retina. Therefore, to extract optimal stimulation parameters in rd10 retina, first we might define selection criteria for responding rd10 ganglion cells to electrical stimulus.
Animals ; Electric Stimulation ; Fourier Analysis ; Ganglion Cysts ; Humans ; Mice ; Microelectrodes ; Models, Animal ; Patient Selection ; Retina ; Retinal Degeneration ; Retinal Ganglion Cells ; Retinaldehyde

BACKGROUDN: Gastrointestinal bleeding (GIB) is not a rare complication in end-stage renal disease (ESRD) patients on dialysis and the occurrence of GIB has also been associated with higher morbidity and mortality rates. However, reasons for the high incidence of GIB are not clear. This retrospective study was undertaken not only to analyze the clinical features of GIB but also to elucidate the independent risk factors for GIB in Korean ESRD patients. METHODS: One hundred thirty ESRD patients on dialysis at the Severance Hospital of Yonsei University College of Medicine from January 2000 to December 2005 were included in the study. The patients were divided into two groups: 65 patients with GIB (the GIB group) and 65 age-, sex-, and dialysis modality-matched patients without GIB (the C group). Clinical characteristics, medications, and laboratory findings were compared between the two groups. RESULTS: Compared to the C group, congestive heart failure (40.0% vs. 21.5%, p<0.05), coronary arterial occlusive disease (CAOD) (32.3% vs. 4.6%, p<0.005), and nonsteroidal anti-inflammatory drug (NSAID) use (18.4% vs. 1.5%, p<0.01) were significantly more common in the GIB group. The baseline serum albumin levels were significantly lower in the GIB group than in the C group (2.53+/-0.67 g/dL vs. 3.56+/-0.63 g/dL, p<0.005). Using logistic regression analysis, CAOD (OR=23.0), NSAID use (OR=12.5), and lower serum albumin levels (OR=2.9) were identified as independent risk factors for GIB (p<0.05). CONCLUSIONS: Careful attention must be paid to ESRD patients with CAOD, taking NSAIDs, or with low serum albumin levels in view of GIB.
Anti-Inflammatory Agents, Non-Steroidal ; Arterial Occlusive Diseases ; Dialysis ; Heart Failure ; Hemorrhage* ; Humans ; Incidence ; Kidney Failure, Chronic* ; Logistic Models ; Mortality ; Retrospective Studies ; Risk Factors* ; Serum Albumin