Person: Guo, Xiaoqing
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Guo
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Xiaoqing
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Guo, Xiaoqing
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Publication PDGFRα Is a Key Regulator of T1 and T3's Differential Effect on SMA Expression in Human Corneal Fibroblasts(The Association for Research in Vision and Ophthalmology, 2017) Sriram, Sriniwas; Tran, Jennifer A.; Guo, Xiaoqing; Hutcheon, Audrey; Lei, Hetian; Kazlauskas, Andrius; Zieske, JamesPurpose The goal of this study was to examine the mechanism behind the unique differential action of transforming growth factor β3 (TGF-β3) and TGF-β1 on SMA expression. It was our hypothesis that platelet-derived growth factor receptor α (PDGFRα) played a key role in determining TGF-β3's response to wounding. Methods: A stable cell line, human corneal fibroblast (HCF)-P, was created from HCFs by knocking down PDGFRα expression using a lentivirus-delivered shRNA sequence. A three-dimensional (3D) in vitro model was constructed by culturing HCF or HCF-P on poly-transwell membranes for 4 weeks in the presence and absence of 0.1 ng/mL TGF-β1 or -β3. At the end of 4 weeks, the constructs were processed for immunofluorescence and reverse transcription–quantitative polymerase chain reaction (RT-qPCR). In addition, HCF and HCF-P cell migration was evaluated. Results: In HCF, TGF-β3 treatment resulted in significantly lower α-smooth muscle actin (SMA) mRNA expression and immunolocalization when compared to TGF-β1, while in HCF-P, both TGF-β1 and -β3 treatment increased the SMA mRNA expression and immunolocalization compared to both the untreated HCF-P control and TGF-β3-treated HCF. Human corneal fibroblast-P also had a lower migration rate and construct thickness when compared to HCF. Conclusions: These results show that TGF-β3 decreases SMA in HCF, while remarkably increasing SMA in HCF-P, thus indicating that the presence or absence of PDGFRα elicits contrasting responses to the same TGF-β3 treatment. Understanding the role of PDGFRα in TGF-β3's ability to stimulate SMA may potentially help in understanding the differential functions of TGF-β1 and TGF-β3 in corneal wound healing.Publication Valuing Mortality Risk in China: Comparing Stated-Preference Estimates From 2005 and 2016(Springer Science and Business Media LLC, 2019-06) Geng, Fangli; Guo, Xiaoqing; Hammitt, James; Nielsen, ChrisWe estimate the marginal rate of substitution of income for reduction in current annual mortality risk (the “value per statistical life” or VSL) using stated- preference surveys administered to independent samples of the general population of Chengdu China in 2005 and 2016. We evaluate the quality of estimates by the theoretical criteria that WTP for risk reduction should be strictly positive and nearly proportional to the magnitude of the risk reduction (evaluated by comparing answers between respondents) and test the effect of excluding respondents whose answers violate these criteria. For subsamples of respondents that satisfy the criteria, point estimates of the sensitivity of WTP to risk reduction are consistent with theory and yield estimates of VSL that are two to three times larger than estimated using the full samples. Between 2005 and 2016, estimated VSL increased sharply, from about 22,000 USD in 2005 to 550,000 USD in 2016. Income also increased substantially over this period. Attributing the change in VSL solely to the change in income implies an income elasticity of about 2.5. Our results suggest that estimates of VSL from stated-preference studies in which WTP is not close to proportionate to the stated risk reduction may be biased downward by a factor of two or more, and that VSL is likely to grow rapidly in a population with strong economic growth, which implies that environmental-health, safety, and other policies should become increasingly protective.