Objective To explore the preparation and identification of amyloid-β protein 1-42 (Aβ1-42) oligomers and their effect on in vitro cultured astrocytes in mice.Methods (1) Aβ1-42peptides were dissolved and 100 μ mol/L Aβ1-42 polypeptide was chosen as mother liquor;and then,they were incubated under different conditions (4 ℃ for 24 h,4 ℃ for 72 h,37 ℃ for 24 h and 37 ℃ for 72 h);the form of Aβ-42 was observed under electron microscope and the degrees of Aβ1-42 polymerization were detected by Western blotting.(2) Aβ1-42 oligomers of different concentrations (Aβ1-42 polypeptide as mother liquor being incubated under condition of 4 ℃ for 24 h) were added into the in vitro cultured astrocytes;CCK-8 assay was used to detect the effects ofAβ1-42 oligomers (0,0.1,0.5,1,5,10,50,and 100 μmol/L) on astrocytic viability;after 0,1,10,and 50 μmol/L Aβ1-42 oligomers treatment,immunofluorescence was employed to detect the morphological changes of astrocytes and Western blotting was used to detect the glial fibrillary acidic protein (GFAP) and aquaporin-4 (AQP4) expressions.Results (1) Different forms and degrees of polymerization of Aβ1-42 could be observed by electron microscope and Western blotting:100 μmol/L Aβ1-42 polypeptides could induce 10 nm granulated mixture of Aβ1-42 oligomers at 4 ℃ incubation for 24 h;proteins with relative molecular mass of 10 000 had decreased expression,and those of 15 000-25 000 had increased expression.(2) Twenty-four h after Aβ1-42oligomers treatment,the viability of astrocytes was increased gradually:as compared with the 0 μmol/L Aβ1-42 oligomer treatment group,the 10,50 and 100 μmol/L Aβ1-42 oligomer treatment groups had significantly increased viability of astrocytes (P＜0.05);immunofluorescent staining indicated that as compared with the 0 μmol/L Aβ1-42 oligomer treatment group,the one,10,and 50 μmol/L Aβ1-42 oligomer treatment groups had activated astrocytes:enlarged soma,increased cell processes and increased GFAP fluorescence intensity were noted;Western blotting indicated that following the increased oligomer concentrations,the protein expressions of GFAP and AQP4 increased:as compared with the 0 μmol/L Aβ1-42 oligomer treatment group,the 10 and 50 μmol/L Aβ1-42 oligomer treatment groups had significantly increased GFAP protein expression (P＜0.05);and as compared with the 0 μmol/L Aβ1-42 oligomer treatment group,the one,10,and 50 μmol/L Aβ1-42 oligomer treatment groups had significantly increased AQP4 protein expression (P＜0.05) Conclusions The Aβ1-42 oligomers could be prepared with 100 μmol/L peptide under 4 ℃ for 24 h.Aβ1-42 oligomers could activate astrocytes and up-regulate the AQP4 expression,which might be a self protective mechanism.

Objective To study the diagnostic value and clinical efficacy of endoscopic ultrasound-guided fine needle aspiration ( EUS-FNA ) for mediastinal and abdominal lymphadenopathy. Methods Thirty patients who underwent EUS-FNA for mediastinal or abdominal lymphadenopathy between May 2009 and December 2015 were reviewed. The clinical efficacy of EUS-FNA was evaluated by pathological results and the follow-up. The EUS-FNA effect on clinical decision was also analyzed. Results Lesions were located in the mediastinum in 10 cases and in the abdomen in 20 cases. The total diagnostic accuracy, sensitivity, specificity, positive predictive value ( PPV) and negative predictive value ( NPV) of EUS-FNA were 96. 7%, 94. 7%, 100. 0%, 100. 0% and 91. 7%, respectively. Of all the 30 cases, 20 lymph glands were of unknown origin. The diagnostic accuracy, sensitivity, specificity, PPV and NPV of EUS-FNA in these lesions were 95. 0%, 88. 9%, 100. 0%, 100. 0% and 91. 7%, respectively. The combination of cytological and histological examination had higher accuracy ( 96. 7% VS 73. 3%, P=0. 026) and sensitivity ( 94. 7%VS 57. 8%, P= 0. 019 ) than cytological examination only. Immunohistochemistry stains were performed in 12 neoplastic cases, and 11 ( 91. 7%) were confirmed. The diagnosis by EUS-FNA had positive impact on clinical decisions in 27 patients ( 90. 0%) . Conclusion EUS-FNA is an effective approach for mediastinal and abdominal lymphadenopathy, and the result has a positive impact on clinical decisions. The combination of cytological and histological examination and application of ancillary techniques, such as immunohistochemistry stains, can improve the diagnostic efficacy of EUS-FNA.