Previous studies suggest that the rhombic lip, a germinal zone, first gives rise to the hindbrain roof plate epithelium (hRPe), which is further specified, potentially by high levels of Bmp signaling( Hebert et al., 2002), into definitive hChPe ( Thomas and Dziadek,1993). The hChP epithelium (hChPe)initially emerges as a single sheet of pseudostratified cells, but by E13.5 the hChPe adopts a simple columnar morphology with numerous microvilli at the surface ( Sturrock, 1979). hChP consists of an outer epithelial layer and an inner core of stromal cells that are surrounded by a dense vascular network. Outgrowth of the hChP is clearly evident at E12.5 as a pair of bilateral ridges protruding from the roof of the hindbrain, gradually developing into a highly convoluted organ with extensive epithelial folding. Among all ChPs, hChP emerges earliest during embryogenesis and is conspicuously large. ChPs originate from four focal sites at the roof of the brain ventricles: two in the lateral ventricles of the telencephalon, one in the third ventricle of the diencephalon and one in the fourth ventricle of the hindbrain (hChP). The ChP epithelium has been the focus of extensive studies, as it serves as the blood-CSF barrier( Redzic et al., 2005 Segal, 2000). Whereas previous studies show that direct contribution to the hChPe by the LRL ceases around E14, our findings reveal a novel tissue-autonomous role for Shh production and signaling in driving the continual growth and expansion of the hindbrain choroid plexus throughout development.Ĭhoroid plexuses (ChPs) are heavily vascularized secretory organs in the brain, which serve as sites of cerebrospinal fluid (CSF) production and are also known to generate chemicals and polypeptides with neuroprotective,surveillance and repair functions. By conditional Shh mutant analysis, we show that Shh signaling regulates hChPe progenitor proliferation and hChPe expansion through late embryonic development, starting around E12.5. We find that this distinct Shh target field that adjoins a germinal zone, the lower rhombic lip (LRL), functions as a progenitor domain by contributing directly to the hChPe. However, we identify a distinct epithelial domain in the hChP that does not express Shh,but displays Shh signaling. Sonic hedgehog (Shh), a secreted signal crucial for embryonic development and cancer, is strongly expressed in the differentiated hindbrain ChP epithelium (hChPe). Despite their crucial roles, there is limited understanding of the regulatory mechanism driving ChP development. Would very much appreciate it, if someone could solve this problem.Choroid plexuses (ChPs) are vascularized secretory organs involved in the regulation of brain homeostasis, and function as the blood-cerebrospinal fluid(CSF) barrier. I would merely like to be able to use the lightscribe labeler again, but cannot because of the Sonic Express Labeler inablility to open. I actually like this program, and have no problems with the other components. Have checked Roxio updates, but obviously the program I have is too old for them to be bothered about. I have contacted Microvision Development, no luck there either. I have updated Lightscribe Software to the latest version, still no luck. The error message I get to send to Microsoft indicates a problem with Stax.exe AppVer. I have uninstalled and reinstalled the applications numerous times, without success. I have tried HP for support but none of their suggestions have fixed the problem. I recently had to do a system restore and since that time am unable to open Sonic Express Labeler 2.1.0.23. I have been using Sonic Digital Media Plus v7 for about four years without experiencing any problems.
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