Ischemic Colitis: Clinical Presentation, Localization in Relation to Risk Factors, and Long-Term Results

Background: Ischemic colitis is commonly thought to occur most often in the left hemicolon close to the splenic flexure owing to insufficient blood supply near Griffith's point. This study investigates the colorectal localization pattern, the risk factors, and the long-term outcome of histologically proven ischemic colitis. Methods: Between 1996 and 2004, a total of 49 patients with a median age of 69years (range 26-94years) with colonoscopically assessed and histologically proven ischemic colitis were identified on behalf of the pathology database. Long-term results of 43 patients were evaluated retrospectively after a median interval of 79months (range 6-163months). Results: In 27 patients (55%) more than one location was affected. We found 98 affected locations in 49 patients. The distribution of ischemic colitis in our group shows no significantly preferred location. In an exploratory analysis, the cecum, ascending colon, and right flexure were affected significantly more often if intake of a nonsteroidal antiinflammatory drug (NSAID) is documented. There was no association between the location of ischemic colitis and a history of smoking, peripheral artery occlusive disease, coronary heart disease, diabetes, or malignant tumor. Conclusions: Ischemic colitis seems not to have a predisposing site of occurrence in the colorectum, especially Griffith's point which was not afflicted significantly more often than other sites. Frequently, ischemic colitis afflicts more than one colonic location. In patients being treated with NSAIDs, ischemic colitis was observed significantly more often in the right hemicolon. Recurrence of ischemic colitis seems to be rar

Arxes: retrotransposed genes required for adipogenesis

Retrotransposed sequences arise from messenger RNAs (mRNAs) that have been reinserted into genomic DNA by reverse transcription. Usually, these sequences are embedded in dormant regions, collect missense mutations over time and constitute processed, nonfunctional pseudogenes. There are thousands of processed pseudogenes in the mouse and human genome. Here, we report evidence for two paralog genes (termed Arxes1 and Arxes2), which arose by retrotransposition of the signal peptidase Spcs3 followed by a segmental duplication event. They gained a functional promoter that we show to be transactivated by adipogenic transcription factors. We further show that the Arxes mRNAs are highly expressed in adipose tissue and strongly upregulated during adipogenesis in different cell models. Additionally, their expression is elevated by an anti-diabetic agent in vitro and in vivo. Importantly, we provide evidence that the Arxes genes are translated and that the proteins are located in the endoplasmic reticulum. Although the sequence similarity and subcellular location are reminiscent of their parental gene, our data suggest that the Arxes have developed a different function, since their expression is required for adipogenesis, whereas Spcs3 is dispensable. In summary, we report retrotransposed-duplicated genes that evolved from a parental gene to function in a tissue and adipogenesis-specific context

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements