INSM1 expression was significantly increased in neoplastic vs nonneoplastic tissue. Furthermore, among midgut GI-NENs, neoplasms with known metastases showed significantly higher expression than those that had not yet metastasized.
International audienceA high-resolution pollen and Pediastrum record, spanning 12,500 yr, is presented for Lake Bayanchagan (115.21E, 41.65N, and 1355 in a.s.l.), southern Inner Mongolia. Individual pollen taxa (PT-MAT) and the PFT affinity scores (PFT-MAT) were used for quantitative climatic reconstruction from pollen and algal data. Both techniques indicate that a cold and dry climate, similar to that of today, prevailed before 10,500 cal yr B.P. The wettest climate occurred between similar to 10,500 and 6500 cal yr B.P., at which time annual precipitation was up to 30-60% higher than today. The early Holocene increases in temperature and precipitation occurred simultaneously, but mid-Holocene cooling started at approximately 8000 cal yr B.P., 1500 yr earlier than the drying. Vegetation reconstruction was based on the objective assignment of pollen taxa to the plant functional type. The results suggest that this region was dominated by steppe vegetation throughout the Holocene, except for the period similar to 9200 to similar to 6700 cal yr B.P., when forest patches were relatively common. Inner Mongolia is situated at the limit of the present East Asian monsoon and patterns of vegetation and climate changes in that region during the Holocene probably reflect fluctuations in the monsoon's response to solar insolation variations. The early to middle Holocene monsoon undoubtedly extended to more northern latitudes than at present. (c) 2005 University of Washington. All rights reserved
Abstract. We correlate the China loess and Antarctica ice records to address the inter-hemispheric climate link over the past 800 ka. The results show a broad coupling between Asian and Antarctic climates at the glacial-interglacial scale. However, a number of decoupled aspects are revealed, among which marine isotope stage (MIS) 13 exhibits a strong anomaly compared with the other interglacials. It is characterized by unusually positive benthic oxygen (δ 18 O) and carbon isotope (δ 13 C) values in the world oceans, cooler Antarctic temperature, lower summer sea surface temperature in the South Atlantic, lower CO 2 and CH 4 concentrations, but by extremely strong Asian, Indian and African summer monsoons, weakest Asian winter monsoon, and lowest Asian dust and iron fluxes. Pervasive warm conditions were also evidenced by the records from northern high-latitude regions. These consistently indicate a warmer Northern Hemisphere and a cooler Southern Hemisphere, and hence a strong asymmetry of hemispheric climates during MIS-13. Similar anomalies of lesser extents also occurred during MIS-11 and MIS-5e. Thus, MIS-13 provides a case that the Northern Hemisphere experienced a substantial warming under relatively low concentrations of greenhouse gases. It suggests that the global climate system possesses a natural variability that is not predictable from the simple response of northern summer insolation and atmospheric CO 2 changes. During MIS-13, both hemispheres responded in different ways leading to anomalous continental, marine and atmospheric conditions at the global scale. The correlations also suggest that the marine δ 18 O record is not always a reliable indicator of the northern ice-volume changes, and that the asymmetry of hemispheric climates is one of the prominent factors controlCorrespondence to: Z. T. Guo (ztguo@mail.iggcas.ac.cn) ling the strength of Asian, Indian and African monsoon circulations, most likely through modulating the position of the inter-tropical convergence zone (ITCZ) and land-sea thermal contrasts.
Thyroid carcinoma is the most common endocrine malignancy, and papillary thyroid carcinoma represents the most common thyroid cancer. Papillary thyroid carcinomas that invade locally or metastasize are associated with a poor prognosis. We found that, during epithelial-mesenchymal transition (EMT) induced by transforming growth factor-β1 (TGF-β1), papillary thyroid carcinoma cells acquired increased cancer stem cell-like features and the transcription factor paired-related homeobox protein 1 (PRRX1; alias PRX-1), a newly identified EMT inducer, was markedly up-regulated. miR-146b-5p was also transiently up-regulated during EMT, and in siRNA experiments miR-146b-5p had an inhibitory role on cell proliferation and invasion during TGF-β1-induced EMT. We conclude that papillary thyroid carcinoma tumor cells exhibit increased cancer stem cell-like features during TGF-β1-induced EMT, that miR-146b-5p has a role in cell proliferation and invasion, and that PRRX1 plays an important role in papillary thyroid carcinoma EMT and disease progression.
Understanding the molecular mechanisms involved in thyroid cancer progression may provide targets for more effective treatment of aggressive thyroid cancers. Epithelial-mesenchymal transition (EMT) is a major pathologic mechanism in tumor progression and is linked to the acquisition of stem-like properties of cancer cells. We examined expression of ZEB1 which activates EMT by binding to the E-box elements in the E-cadherin promoter, and expression of E-cadherin in normal and neoplastic thyroid tissues in a tissue microarray (TMA) which included 127 neoplasms and 10 normal thyroid specimens. Thyroid follicular adenomas (FA, n=32), follicular thyroid carcinomas (FTC, n=28), and papillary thyroid carcinomas (PTC, n=57) all expressed E-cadherin and were mostly negative for ZEB1 while most anaplastic thyroid carcinomas (ATC, n=10) were negative for E-cadherin, but positive for ZEB1. A validation set of 10 whole sections of ATCs showed 90% of cases positive for ZEB1 and all cases were negative for E-cadherin. Analysis of three cell lines (normal thyroid, NTHY-OR13-1; PTC, TPC-1 and ATC, THJ-21T) showed that the ATC cell line expressed the highest levels of ZEB1 while the normal thyroid cell line expressed the highest levels of E-Cadherin. Quantitative RT-PCR analyses showed that Smad7 mRNA was significantly higher in ATC than in any other group (p<0.05). These results indicate that ATCs show evidence of EMT including decreased expression of E-cadherin and increased expression of ZEB1 compared to well differentiated thyroid carcinomas and that increased expression of Smad7 may be associated with thyroid tumor progression.
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