Bilateral Bow-Hunter's Stroke Caused by Sleeping in Prone Position: A Case of Recurrent Posterior Circulation Infarction.

OBJECTIVES: Bow hunter's stroke (BHS) is a condition characterized by temporary vertebrobasilar insufficiency caused by mechanical compression or occlusion of the vertebral artery when the head is rotated, leading to transient neurological symptoms such as dizziness, vertigo, nystagmus, dysarthria, and potentially stroke. Therefore, a situation in which the head remains rotated for an extended period is a significant risk factor for BHS. MATERIALS AND METHODS: We present a case of a 25-year-old woman who experienced three recurrent cerebral infarctions in the posterior circulation area after sleeping in a prone position with her head rotated. RESULTS: The first infarction occurred in the right thalamus, followed by bilateral cerebellar infarctions, and finally, an infarction in the left cerebellar hemisphere. Carotid Doppler ultrasonography revealed blood flow interruption in the left vertebral artery due to head rotation, and digital subtraction angiography showed that rotation of the head to one side resulted in blood flow disruption of the contralateral vertebral artery in both right and left rotation. A C1-2 posterior fixation surgery was performed to stabilize the atlas and axis using screws and rods, with no recurrence observed thereafter. CONCLUSIONS: When encountering a young patient with recurrent posterior circulation infarctions upon awakening, it is crucial to inquire about the patient's sleeping position, such as prone positioning, to assess for potential vertebral artery stenosis or occlusion due to head rotation.

Sparse Activity of Hippocampal Adult-Born Neurons during REM Sleep Is Necessary for Memory Consolidation.

The occurrence of dreaming during rapid eye movement (REM) sleep prompts interest in the role of REM sleep in hippocampal-dependent episodic memory. Within the mammalian hippocampus, the dentate gyrus (DG) has the unique characteristic of exhibiting neurogenesis persisting into adulthood. Despite their small numbers and sparse activity, adult-born neurons (ABNs) in the DG play critical roles in memory; however, their memory function during sleep is unknown. Here, we investigate whether young ABN activity contributes to memory consolidation during sleep using Ca2+ imaging in freely moving mice. We found that contextual fear learning recruits a population of young ABNs that are reactivated during subsequent REM sleep against a backdrop of overall reduced ABN activity. Optogenetic silencing of this sparse ABN activity during REM sleep alters the structural remodeling of spines on ABN dendrites and impairs memory consolidation. These findings provide a causal link between ABN activity during REM sleep and memory consolidation.

miR-200b precursor can ameliorate renal tubulointerstitial fibrosis.

Members of the miR-200 family of micro RNAs (miRNAs) have been shown to inhibit epithelial-mesenchymal transition (EMT). EMT of tubular epithelial cells is the mechanism by which renal fibroblasts are generated. Here we show that miR-200 family members inhibit transforming growth factor-beta (TGF-beta)-induced EMT of tubular cells. Unilateral ureter obstruction (UUO) is a common model of EMT of tubular cells and subsequent tubulointerstitial fibrosis. In order to examine the role of miR-200 family members in tubulointerstitial fibrosis, their expression was investigated in the kidneys of UUO mice. The expression of miR-200 family miRNAs was increased in a time-dependent manner, with induction of miR-200b most pronounced. To clarify the effect of miR-200b on tubulointerstitial fibrosis, we injected miR-200b precursor intravenously. A single injection of 0.5 nM miR-200b precursor was sufficient to inhibit the increase of collagen types I, III and fibronectin in obstructed kidneys, and amelioration of fibrosis was confirmed by observation of the kidneys with Azan staining. miR-200 family members have been previously shown to inhibit EMT by reducing the expression of ZEB-1 and ZEB-2 which are known repressors of E-cadherin. We demonstrated that expression of ZEB-1 and ZEB-2 was increased after ureter obstruction and that administration of the miR-200b precursor reversed this effect. In summary, these results indicate that miR-200 family is up-regulated after ureter obstruction, miR-200b being strongly induced, and that miR-200b ameliorates tubulointerstitial fibrosis in obstructed kidneys. We suggest that members of the miR-200 family, and miR-200b specifically, might constitute novel therapeutic targets in kidney disease.