Multiple stressors produce differential transcriptomic patterns in a stream-dwelling salamander.

BACKGROUND: Global biodiversity is decreasing at an alarming rate and amphibians are at the forefront of this crisis. Understanding the factors that negatively impact amphibian populations and effectively monitoring their health are fundamental to addressing this epidemic. Plasma glucocorticoids are often used to assess stress in amphibians and other vertebrates, but these hormones can be extremely dynamic and impractical to quantify in small organisms. Transcriptomic responses to stress hormones in amphibians have been largely limited to laboratory models, and there have been few studies on vertebrates that have evaluated the impact of multiple stressors on patterns of gene expression. Here we examined the gene expression patterns in tail tissues of stream-dwelling salamanders (Eurycea tynerensis) chronically exposed to the stress hormone corticosterone under different temperature regimes. RESULTS: We found unique transcriptional signatures for chronic corticosterone exposure that were independent of temperature variation. Several of the corticosterone responsive genes are known to be involved in immune system response (LY-6E), oxidative stress (GSTM2 and TRX), and tissue repair (A2M and FX). We also found many genes to be influenced by temperature (CIRBP, HSC71, HSP40, HSP90, HSP70, ZNF593). Furthermore, the expression patterns of some genes (GSTM2, LY-6E, UMOD, ZNF593, CIRBP, HSP90) show interactive effects of temperature and corticosterone exposure, compared to each treatment alone. Through a series of experiments we also showed that stressor induced patterns of expression were largely consistent across ages, life cycle modes, and tissue regeneration. CONCLUSIONS: Outside of thermal stressors, the application of transcriptomes to monitor the health of non-human vertebrate systems has been vastly underinvestigated. Our study suggests that transcriptomic patterns harbor stressor specific signatures that can be highly informative for monitoring the diverse stressors of amphibian populations.

Inflammatory fibroid polyp of the gastric antrum presenting as hypovolemic shock: Case report and literature review.

Inflammatory fibroid polyps (IFP) are an extremely rare entity that arise within the submucosa of the gastrointestinal tract, and represent less than 0.1% of all gastric polyps. They are most commonly localized to the gastric antrum, small intestines and recto-sigmoid colon. IFPs are most commonly found incidentally upon endoscopic evaluation in the absence of symptoms. Presenting symptoms depend on the location of the tumor, although polyps located in the stomach most commonly present with epigastric pain and early satiety. Classic histologic features include perivascular onion skinning of spindle cells with an abundance of eosinophilic infiltration. The prompt diagnosis and management of IFP is essential due to its underlying risk for intussusception, outlet obstruction and acute hemorrhage. In addition, recent evidence has shown that IFP is driven by an activating mutation in the platelet derived growth factor receptor alpha (PDGFRA) gene, suggesting a neoplastic etiology. Herein, we discuss a case of a 65-year-old woman with an inflammatory fibroid polyp of the gastric antrum who initially presented with early hypovolemic shock and melena. Diagnosis was made by endoscopic visualization, biopsy and immunohistochemical analysis.