Natural and anthropogenic changes in atmospheric greenhouse gases over the past 2 millennia

Millennial changes in atmospheric trace gas composition are best determined from air enclosed in ice sheets. Air extracted from the open pores in firn and the bubbles in ice is measured to derive the past concentrations and isotopic ratios of the long lived trace gases. The significant increases observed in CO2, CH4 and N2O since about 1750 and the more recent appearance of synthetic gases such as the CFCs in the atmosphere are a key feature of the anthropocene. The millennia preceding the anthropocene, the Late Pre-Industrial Holocene (LPIH), show evidence of natural changes in trace gases that can be used to constrain models and improve their ability to predict future changes under scenarios of anthropogenic emissions and climate change. Precise measurements and ice core air samples that are accurately dated and highly resolved in time are required to record the small and rapid trace gas signals of this period. The atmospheric composition records produced by CSIRO and collaborators using the Law Dome, Antarctica ice cores are widely used in models of climate, atmospheric chemistry and the carbon cycle over the anthropocene and the LPIH. Results from these studies have been influential in informing global policies, including the Montreal and Kyoto Protocols. We will present the recently revised trace gas records from Law Dome and new measurements of tracers from these and other ice sites that reveal the causes of atmospheric changes over the anthropocene and the LPIH

Immunohistochemical analysis of coeliac mucosa following ingestion of oats

There is now considerable clinical evidence that oats do not activate coeliac disease. Nonetheless, a reluctance to include oats in the gluten-free diet remains. Because gluten-induced damage is accompanied by activation of the gastrointestinal immune system, the purpose of this study was to investigate if similar changes were induced by oats ingestion. Small intestinal histological sections from 10 patients who ingested 50 g of oats daily for 3 months were investigated for possible evidence of immune activation. Tissue obtained before and after oats challenge was stained with a series of antibodies directed against the following molecules: human leucocyte antigen D-related (HLA-DR), Ki-67, CD25, CD54 [intercellular adhesion molecule 1 (ICAM-1)] and mast cell tryptase. None of the patients developed clinical or laboratory evidence of adverse effects. The distribution of intestinal HLA-DR expression was not affected by oats ingestion and the crypt epithelium remained unstained. In the pre-oats biopsies, the percentage of Ki-67 positive enterocytes, 29·5 ± 6·9 [95% confidence interval (CI) 13·9–45·0] did not differ significantly from that found in postoats biopsies, 41·2 ± 3·7 (95% CI, 32·8–49·6), P = 0·19, not significant. Furthermore, oats ingestion did not alter the number of CD25 positive and tryptase positive cells. Finally, the distribution and intensity of ICAM-1 staining was unchanged by dietary oats. In summary, detailed immunohistological studies of biopsies from patients ingesting oats for 3 months did not reveal evidence of immune activation. Together with other reported findings, this study strengthens the view that oats can be included safely in the diet of gluten sensitive patients