ABSTRACT
Drosophila neural development undergoes extensive chromatin remodeling and precise epigenetic regulation. However, the roles of chromatin remodeling in establishment and maintenance of cell identity during cell fate transition remain enigmatic. Here, we compared the changes in gene expression, as well as the dynamics of nucleosome positioning and key histone modifications between the four major neural cell types during Drosophila neural development. We find that the neural progenitors can be separated from the terminally differentiated cells based on their gene expression profiles, whereas nucleosome distribution in the flanking regions of transcription start sites fails to identify the relationships between the progenitors and the differentiated cells. H3K27me3 signal in promoters and enhancers can not only distinguish the progenitors from the differentiated cells but also identify the differentiation path of the neural stem cells (NSCs) to the intermediate progenitor cells to the glial cells. In contrast, H3K9ac signal fails to identify the differentiation path, although it activates distinct sets of genes with neuron-specific and glia-related functions during the differentiation of the NSCs into neurons and glia, respectively. Together, our study provides novel insights into the crucial roles of chromatin remodeling in determining cell type during Drosophila neural development.
ABSTRACT
<p><b>OBJECTIVE</b>To investigate the safety and feasibility of intracorporeal Roux-en-Y reconstruction after laparoscopic distal gastrectomy.</p><p><b>METHODS</b>Clinical data of 20 patients undergoing laparoscopic distal gastrectomy and intracorporeal Roux-en-Y reconstruction in our hospital from August 2012 to March 2013 were analyzed retrospectively.</p><p><b>RESULTS</b>Totally laparoscopic distal gastrectomy was successfully performed in all the patients. The mean operation time was (190.8±53.6) min, the mean operative blood loss was(122.4±57.7) ml, and mean number of harvested lymph node was 31.2±5.7. Tumor-free proximal margin was confirmed by pathological examination in all the patients. The mean time to first flatus and hospital stay were (2.6±1.6) d and (8.1±2.0) d. One case developed pulmonary infection postoperatively, but no anastomosis related complication was observed.</p><p><b>CONCLUSION</b>Intracorporeal Roux-en-Y reconstruction after laparoscopic distal gastrectomy is safe and feasible.</p>