Proteomic analysis of pancreatic intraepithelial neoplasia and pancreatic carcinoma in rat models

AIM:To detect the proteomic variabilities of pancreatic intraepithelial neoplasia(PanIN)and pancreatic carcinoma(PC)induced by 7,12-dimethylbenzanthracene(DMBA) in rat models and to identify potential biomarkers.METHODS:Sixty adult male Sprague Dawley rats were randomized into three groups.The rats had DMBA implanted into their pancreas for one(n=20)or two months(n=20)or assigned to the normal group(n =20).The rats were killed after one or two months,and were evaluated histopathologically.Three tissue samples from each group of rats with either normal pancreas,PanIN(PanIN-2)or PC were examined by 2D-DIGE.The different expression spot features were analyzed by matrix-assisted laser desorption/ionizationtime of flight/time of flight(MALDI-TOF/TOF)tandem mass spectrometry.The expression of enolase 1,a differentially expressed protein,was identified by immu-nohistochemistry.RESULTS:There was significant difference in the proportions of neoplastic changes between the 1-and 2-mogroups(P=0.0488).There was an increase in the frequency of adenocarcinomas in the 2-mo group compared with the 1-mo group(P=0.0309).No neoplastic changes were observed in any of the animals in the normal group.Enolase 1,pancreatic ELA3B,necdin,Hbp23,CHD3,hnRNP A2/B1,Rap80,and Gnb2l1 were up-regulated in the PanIN and PC tissues,and CEL,TPT1,NME2,PCK2,an unnamed protein product,and glycine C-acetyltransferase were down-regulated in the PanIN and PC tissues.The immunohistochemical results showed that enolase 1 expression was up-regulated in the pancreatic cancer tissues of rats and humans.CONCLUSION:The pancreatic protein expression changes induced by DMBA suggest potential molecular targets for the early diagnosis and treatment of PC.

Field Evaluation of Alternative Testing Strategies for the Detection of HIV Infection in Beijing

To identify a cost-efficient altemative antibody testing strategy for screening and confirmation of HIV infection by rapid simple tests （RSTs） and enzyme-linked immunosorbent assays （ELISAs）. Methods Four RSTs （RST1, RST2, RST3, and RST4 ） and five ELISAs （ELISA1, ELISA2, ELISA3, ELISA4, and ELISA5） were evaluated in two phases by using banked and serum specimens prospectively collected at regional hospitals and voluntary counseling and testing （VCT） centers in Beijing. A total of 200 banked serum specimens were included in the first phase, including 62 HIV-positive, 127 HIV-negative and 11 indeterminate specimens. All specimens were tested by four RSTs and five ELISAs respectively. The second phase involved prospective testing of 389 routine specimens, including 92 HIV-positive, 287 HIV-negative, and 10 indeterminate specimens. All the specimens were tested by two RSTs （RST2 and RST4） and three ELISAs （ELISA1, ELISA3, and ELISA4）, which were selected for their respective excellent sensitivity and/or specificity. Westem blot （WB） was used as a gold standard for confirming the reactivity of all the specimens. Results Sensitivity, specificity, and efficacy were calculated for each assay in two phases. In the first phase, four assays （ELISA4, RST2, RST3, and RST4） had a specificity of 100%. For the determination of efficacy, ELISA4, RST2, and RST4 were selected in the second phase. ELISA1 and ELISA3 which have a sensitivity of 95.9% and 93.2% respectively also entered this phase. In the second phase, all the five assays （ELISA1, ELISA3, ELISA4, RST2, and RST4） had a sensitivity and specifity of over 90%. ELISA1 had a sensitivity of 99% and ELISA4 a specificity of 99%. Conclusion The sensitivity ELISA1 and the specificit of ELISA4 are comparable to ELISA/WB standard strategy. Application of this alternative testing strategy provides a cost-effective method for determining HIV prevalence in Beijing.

Mechanical and microstructural characterization of additive manufactured Inconel 718 alloy by selective laser melting and laser metal deposition

The direct comparison of the microstructure and tensile properties of Inconel 718 fabricated by selective laser melting (SLM) or laser metal deposition (LMD) has been carried out. In the as-built state, LMD-fabricated specimens show lower tensile yield strength and fracture elongation than SLM-fabricated specimens due to the coarser solidification microstructure, including grains, cellular dendrites and Laves phases. This is mainly because the cooling rate of the LMD process is 2 to 3 orders lower than that of the SLM process. Upon the same heat treatment, both yield strengths of SLMand LMD-fabricated specimens are enhanced significantly. Notably, LMD-fabricated specimens exhibit simultaneous improvement in the strength and ductility, which is mainly attributed to the presence of small granular Laves phases and uniformly distributed nanoscale c00 strengthening phases. The results could serve as a guidance for selecting suitable postheat treatment routes for specific additive manufacturing process to attain excellent strength-ductility synergy.