Alteration by beta-amyloid (Abeta) of signaling via nicotinic acetylcholine receptors (nAChRs) has been implicated in the early stages of Alzheimer's disease. nAChRs function both post- and presynaptically in the nervous system; however, little is known about the functional consequence of the interaction of Abeta with these receptors, particularly those on presynaptic nerve terminals. In view of the strong correlation between loss of synaptic terminals and dementia, together with the reduction in nAChRs in Alzheimer's disease, the possibility exists that presynaptic nAChRs may be targets for Abeta. To explore this possibility, we assessed the effect of Abeta peptides on nicotine-evoked changes in presynaptic Ca2+ level via confocal imaging of isolated presynaptic nerve endings from rat hippocampus and neocortex. Abeta1-42 appeared to inhibit presynaptic nAChR activation by nicotine. Surprisingly, picomolar Abeta1-42 was found to directly evoke sustained increases in presynaptic Ca2+ via nAChRs, revealing that the apparent inhibitory action of Abeta1-42 was the result of an occlusion of nicotine to further stimulate the receptors. The direct effect of Abeta was found to be sensitive to alpha-bungarotoxin, mecamylamine, and dihydro-beta-erythroidine, indicating involvement of alpha7-containing nAChRs and non-alpha7-containing nAChRs. Prior depolarization strongly attenuated subsequent Abeta-evoked responses in a manner dependent on the amplitude of the initial presynaptic Ca2+ increase, suggesting that nerve activity or Ca2+ channel density may control the impact of Abeta on presynaptic nerve terminal function. Together, these results suggest that the sustained increases in presynaptic Ca2+ evoked by Abeta may underlie disruptions in neuronal signaling via nAChRs in the early stages of Alzheimer's disease.

The IRX1 tumor suppressor gene is located on 5p15.33, a cancer susceptibility locus. Loss of heterozygosity of 5p15.33 in gastric cancer was identified in our previous work. In this study, we analyzed the molecular features and function of IRX1. We found that IRX1 expression was lost or reduced in gastric cancer. However, no mutations were identified in IRX1-encoding regions. IRX1 transcription was suppressed by hypermethylation, and the expression of IRX1 mRNA was partially restored in gastric cancer cells after 5-Aza-dC treatment. Restoring IRX1 expression in SGC-7901 and NCI-N87 gastric cancer cells inhibited growth, invasion and tumorigenesis in vitro and in vivo. We identified a number of target genes by global microarray analysis after IRX1 transfection combined with real-time PCR and chromatin immunoprecipitation assay. BDKRB2, an angiogenesis-related gene, HIST2H2BE and FGF7, cell proliferation and invasionrelated genes, were identified as direct IRX1 target genes. The hypermethylation of IRX1 was not only detected in primary gastric cancer tissues but also in the peripheral blood of gastric cancer patients, suggesting IRX1 could potentially serve as a biomarker for gastric cancer.

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cn. than 0.05 was considered statistically significant. All data were analyzed with SPSS software (IBM). Study approvalEthics approval for this study was obtained from the ethics board for animal research of Southern Medical University (Guangzhou, China). The animals were handled in accordance with the Chinese Council on Animal Care Guidelines. Efforts were made to minimize animal suffering and to reduce the number of animals used.

Purpose: To examine diagnostic performance of qualitative shear wave elastography (SWE) for evaluation of status of axillary lymph nodes (ALN) in comparison with conventional ultrasonograghy (US) and quantitative SWE parameters. Methods: A total of 118 patients were enrolled, who were all scheduled for breast cancer surgery and core needle biopsy. Conventional US and SWE were performed before biopsy. Based on qualitative evaluation of each ALN, the SWE images were classified into four color patterns: Color Pattern 1: homogeneous; Color Pattern 2: filling defect within lymph node (LN); Color Pattern 3: homogeneous within LN with a localized colored area at the margin; and Color Pattern 4: filling defect within LN with a localized colored area at the margin. The diagnostic performances of the three methods were compared. Results: There were 60 metastatic nodes and 61 benign nodes in the 121 ALNs. Benign ALNs were presented as Color Pattern 1 while metastatic ALNs usually were presented as Color Pattern 2 to 4 ( p < 0.05). The AUC of qualitative SWE classification was 0.983, higher than that of quantitative SWE parameters and conventional US ( p <0.05). The highest diagnostic performance, with AUC of 0.998, could be achieved if both conventional US and qualitative SWE were applied. Conclusion: The qualitative SWE classification of ALNs proposed in our study exhibited better diagnostic performance than quantitative SWE parameters and conventional US, especially for differentiating metastatic ALNs from benign reactive ALNs. More accurate diagnosis could be reached with this new method and unnecessary biopsy might be avoided in the meantime.