Nestin is a novel marker for renal tubulointerstitial injury in immunoglobulin A nephropathy

Aim: Nestin, an intermediate filament originally identified as a marker of neural progenitor cells, is transiently expressed in endothelial cells and tubuloepithelial cells during kidney development. However, in adult kidneys, podocytes are the only cells that express nestin. In this study, we examined tubulointerstitial nestin expression in human glomerulonephritis. Methods: Renal biopsy specimens obtained from 41 adult patients with immunoglobulin (Ig)A nephropathy were studied. Nestin expression was determined by immunohistochemical staining and estimated by digital image analysis. To identify the phenotype of nestin‐positive cells, a double immunofluorescent study was performed for nestin and CD34 (a marker for endothelial cells) or α‐smooth muscle actin (α‐SMA, a marker for myofibroblasts). Results: In normal kidney, nestin expression was restricted to the podocytes and was not detected in tubular cells and tubulointerstitial cells. In contrast, increased nestin expression was observed at tubulointerstitial areas of IgA nephropathy. The degree of tubulointerstitial nestin expression was positively correlated with tubulointerstitial fibrosis (r = 0.546, P < 0.001). The double immunofluorescent study showed that most nestin‐positive cells in the interstitium were co‐stained with CD34 or α‐SMA, suggesting that peritubular endothelial cells and tubulointerstitial myofibroblasts express nestin during the progression of tubulointerstitial injury. In addition, strong nestin expression was associated with deterioration of renal function. Conclusion: Nestin expression is associated with tubulointerstitial injury and predicts renal prognosis in IgA nephropathy. Nestin could be a new marker for peritubular endothelial cell injury and tubulointerstitial fibrosis.     

Phasic brain activity related to the onset of rapid eye movements during rapid eye movement sleep: study of event‐related potentials and standardized low‐resolution brain electromagnetic tomography

The function of rapid eye movements (REMs) during REM sleep is still a matter that is open to debate. In a previous study, we found positive brain potential (P200r) time‐locked to the onset of REMs. This potential was not observed during saccades of wakefulness. In this study, we estimated the electrical generation of this potential to investigate the phasic brain activity related to REMs. Data were collected in a sleep laboratory from nine healthy university students. REMs during REM sleep were recorded during natural nocturnal sleep. Event‐related potential time‐locked to the onset of REMs were averaged. Standardized low‐resolution brain electromagnetic tomography (sLORETA) was used to identify the current sources of P200r. The results showed that P200r have neuronal generators in the left premotor area, left primary motor and sensory cortices, left inferior parietal lobule and bilateral occipital areas (precuneus, cuneus and lingual gyrus). All these areas are known to contribute to visuomotor processing. These phasic brain activities might play a key role in explaining the function of REMs during REM sleep.     

Conductive Properties of the Reentrant Pathway of Ventricular Tachycardia During Entrainment From Outside and Within the Zone of Slow Conduction

Ventricular tachycardia (VT) was entrained with rapid ventricular pacing outside and within the zone of slow conduction (SCZ), and the conductive properties of the reentrant pathway were compared between the two pacing sites. Underlying heart diseases were old myocardial infarction (n = 2), postoperative tetralogy of Fallot (n = 1) or double outlet of the right ventricle (n = 1), dilated cardiomyopathy (n = 1), and pulmonary regurgitation of unknown cause (n = 1). Rapid pacing was continued for 5–10 seconds, and the time interval from paced stimulus to the entrained electrogram at the exit from SCZ (St-Ex) or to the QRS complex (St-QRS) was measured. Rapid pacing was performed at three or more cycle lengths after a decrement in steps of 10 msec. During rapid pacing outside of SCZ and entrainment of VT, constant fusion and progressive fusion were observed, and St-Ex and St-QRS showed the same response pattern: either a frequency dependent prolongation in 4 of 7 VTs or a constant time interval in the others VTs. When rapid pacing was attempted within SCZ, the response of the time intervals from paced site to the QRS (St-QRS) was the same as those observed during pacing outside SCZ except for one VT. In VT with repaired tetralogy of Fallot, the frequency dependent prolongation was observed during pacing from outside of SCZ but not within SCZ. Diseased myocardium extending widely into the outflow tract of the right ventricle may be responsible for the frequency dependent prolongation of St-Ex. In conclusion, the conductive property of the reentrant pathway might be assessed by observing the response patterns of St-Ex or St-QRS interval during transient entrainment of VT outside of SCZ, but exceptions may exist.