Daily Archives: December 28, 2017

Central US Climate Changes Attributed to Agriculture

Ross E. Alter, Hunter C. Douglas, Jonathan M. Winter, Elfatih A. B. Eltahir. 20th-century regional climate change in the central United States attributed to agricultural intensification. Geophysical Research Letters. DOI: 10.1002/2017GL075604

Both land-use changes and greenhouse gas (GHG) emissions have significantly modified regional climate over the last century. In the central United States, for example, observational data indicate that rainfall increased, surface air temperature decreased, and surface humidity increased during the summer over the course of the 20th century concurrently with increases in both agricultural production and global GHG emissions. However, the relative contributions of each of these forcings to the observed regional changes remain unclear. Results of both regional climate model simulations and observational analyses suggest that much of the observed rainfall increase – as well as the decrease in temperature and increase in humidity – is attributable to agricultural intensification in the central United States, with natural variability and GHG emissions playing secondary roles. Thus, we conclude that 20th-century land-use changes contributed more to forcing observed regional climate change during the summer in the central United States than increasing GHG emissions.

Fluoride Induces Apoptosis in Cardiomyocytes

Yan X, Wang L, Yang X, Qiu Y, Tian X, Lv Y, Tian F, Song G, Wang T. Fluoride induces apoptosis in H9c2 cardiomyocytes via the mitochondrial pathway. Chemosphere. 2017 Sep;182:159-165. doi: 10.1016/j.chemosphere.2017.05.002. Epub 2017 May 1.

Numerous studies have shown that chronic excessive fluoride intake can adversely affect different organ systems. In particular, the cardiovascular system is susceptible to disruption by a high concentration of fluoride. The objectives of this study were to explore the mechanism of apoptosis by detecting the toxic effects of different concentrations of sodium fluoride (NaF) in H9c2 cells exposed for up to 96 h. NaF not only inhibited H9c2 cell proliferation but also induced apoptosis and morphological damage. With increasing NaF concentrations, early apoptosis of H9c2 cells was increased while the mitochondrial membrane potential was decreased. Compared with the control group, the mRNA levels of caspase-3, caspase-9, and cytochrome c all increased with increasing concentrations of NaF. In summary, these data suggest that apoptosis is involved in NaF-induced H9c2 cell toxicity and that activation of the mitochondrial pathway may occur.