Isoelectric focusing on microfluidic paper-based chips.

Isoelectric focusing (IEF), a powerful technique for protein separation and enrichment, was successfully integrated into microfluidic paper-based analytical devices (µPADs) in this work. The µPADs for isoelectric focusing were fabricated by octadecyltrichlorosilane (OTS) silanization and subsequent region-selective plasma treatment. The system of IEF on µPADs could be easily assembled. And a series of conditions of the system were investigated, including the suitable concentration of ampholyte to create good pH gradient, the effect of polyvinylpyrrolidone (PVP) on electroosmotic flow (EOF) suppression, and focusing voltage applied on the paper channel. After optimization, simultaneous separation and enrichment of protein sample containing myoglobin and cytochrome C was successfully demonstrated. Besides, parallel IEF on multichannels were also achieved for the separation of multiple protein samples on one single chip, and their performance was compared with that of the conventional gel-IEF system. The developed IEF on µPADs exhibits appealing features such as low cost, simplicity, and disposability and are believed to have great application potentials.

GPC-1 may serve as a predictor of perineural invasion and a prognosticator of survival in pancreatic cancer.

OBJECTIVE: The purpose of this study was to investigate the expression of glial cell derived neurotrophic factor (GDNF), glypican-1 (GPC-1), and matrix metalloproteinase-9 (MMP-9), and their association with clinicopathologic characteristics as well as prognostic significance in pancreatic cancer. METHODS: Immunohistochemical assessment of GDNF, GPC-1, and MMP-9 was performed in 62 cases of surgically resected pancreatic cancer. Perineural invasion in pancreatic cancer was observed by marking nerve fiber with S-100, while 16 normal pancreatic tissues were used as normal control. Correlations of GDNF, GPC-1 and MMP-9 expressions with clinicopathologic parameters were analyzed. A survival analysis was performed to find the prognostic significance. RESULTS: The expressions of GDNF, GPC-1 and MMP-9 in pancreatic cancer tissue were significantly higher than of those in normal pancreatic tissues (41/62 vs. 5/16 for GDNF, 35/62 vs. 2/16 for GPC-1, and 37/62 vs. 3/16 for MMP-9; p<0.01, respectively). The overexpression of GDNF, GPC-1, and MMP-9 in pancreatic cancer tissue was significantly related to the perineural invasion (p<0.05). Although the overexpression of these genes was related to poor survival, GPC-1 had an independent prognostic effect on overall survival. CONCLUSION: GPC-1 is significantly related to the perineural invasion of pancreatic cancer, holding some prognostic significance in patients with pancreatic cancer.

[Clinical trial on pancreatic duct stones caused by chronic pancreatitis].

OBJECTIVE: To determine the possible mechanism for chronic pancreatitis causing pancreatic duct stones. METHODS: A total of 172 patients with chronic pancreatitis (n=67), pancreatic duct stones (n=62), and pancreatic injury (n=43), admitted to from August 2000 to October 2008, preoperatively diagnosed by endoscopic retrograde cholangiopancreatograpby(ERCP) or computed tomography(CT), and intraoperatively confirmed by exploration and biopsy, were divided into 3 groups. Pancreatic fluid was drawn to test the concentrations of pancreatic stone protein (PSP), lactoferrin (LF) and Ca2+. RESULTS: The chronic pancreatitis (the CP group) presented hard consistency, shrinkage and nodular fibrosis of the pancreas; besides the above symptoms, the pancreatic duct stones (the PS group) presented dilatation of the pancreatic ductal system with various stones; pancreatic injury (the PI group) presented broken pancreas of different grades with fluid or blood. Compared with that of the PI group, PSP concentration of both the PS group and the CP group was elevated (P<0.05), and was more apparent in the CP group. Concentrations of LF and Ca2+ were also elevated (P<0.05), which were more obvious in the PS group. CONCLUSION: Decreased concentrations of PSP and increased concentrations of LF and Ca2+ may play very important roles in chronic pancreatitis causing pancreatic duct stones.