Naked cuticle inhibits wingless signaling in Drosophila wing development.

Wnt signaling is one of the major signaling pathways that regulate cell differentiation, tissue patterning and stem cell homeostasis and its dysfunction causes many human diseases, such as cancer. It is of tremendous interests to understand how Wnt signaling is regulated in a precise manner both temporally and spatially. Naked cuticle (Nkd) acts as a negative-feedback inhibitor for Wingless (Wg, a fly Wnt) signaling in Drosophila embryonic development. However, the role of Nkd remains controversial in later fly development, particularly on the canonical Wg pathway. In the present study, we show that nkd is essential for wing pattern formation, such that both gain and loss of nkd result in the disruption of Wg target expression in larvae stage and abnormal adult wing morphologies. Furthermore, we demonstrate that a thirty amino acid fragment in Nkd, identified previously in Wharton lab, is critical for the canonical Wg signaling, but is dispensable for Wg/planar cell polarity pathway. Putting aside the pleiotropic nature of nkd function, i.e. its role in the Decapentaplegic signaling, we conclude that Nkd universally inhibits the canonical Wg pathway across a life span of Drosophila development.

Invaginated Pancreaticojejunostomy via the Space Behind the Root of Superior Mesenteric Vessels.

BACKGROUND: This study was to explore a safe and effective procedure to prevent pancreatic fistula (PF) after pancreaticoduodenectomy (PD). METHODS: Forty-three modified PD with pancreaticojejunostomy by direct invagination of the pancreas to the jejunum that was brought up via the space behind the root of superior mesenteric vessel were performed between January 2003 and June 2006, and were compared to the fifty-six conventional PD (Child' method). RESULTS: There was no pancreatic fistula after PD in the modified group. Two cases developed biliary fistula that were successfully treated with complete drainage for 2 to 3 weeks; 2 cases abdominal infection managed with anti-infection and completely drainage; 4 cases stress ulcer cured with Losec and coagulant. Three cases in the Child group developed PF of different severities, with amylase level > 9000 U/L in the abdominal drainage fluid. Two of the PF were treated with Stilamin, parenteral nutrition, fasting and completely drainage and cured after 21 to 32 days. The other 82-year-old patient died. Other complications had no significant difference between the two groups (P > 0.05). CONCLUSIONS: The modified PD can effectively prevent PF and is a safe and effective procedure for periampullary neoplasm. Further studies of its clinical use are warranted.