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Extracellular vesicles (EVs) are of growing interest due to their potential diagnostic, disease surveillance, and therapeutic applications. While several studies have evaluated EV isolation methods in various biofluids, there are few if any data on these techniques when applied to stool. The latter is an ideal biospecimen for studying EVs and colorectal cancer (CRC) because the release of tumour markers by luminal exfoliation into stool occurs earlier than vascular invasion. Since EV release is a conserved mechanism, bacteria in stool contribute to the overall EV population. In this study, we assessed five EV separation methods (ultracentrifugation [UC], precipitation [EQ‐O, EQ‐TC], size exclusion chromatography [SEC], and ultrafiltration [UF]) for total recovery, reproducibility, purity, RNA composition, and protein expression in stool supernatant. CD63, TSG101, and ompA proteins were present in EV fractions from all methods except UC. Human (18s) and bacterial (16s) rRNA was detected in stool EV preparations. Enzymatic treatment prior to extraction is necessary to avoid non‐vesicular RNA contamination. Ultrafiltration had the highest recovery, RNA, and protein yield. After assessing purity further, SEC was the isolation method of choice. These findings serve as the groundwork for future studies that use high throughput omics technologies to investigate the potential of stool‐derived EVs as a source for novel biomarkers for early CRC detection. [ABSTRACT FROM AUTHOR]

Abstract Extracellular vesicles (EVs) are of growing interest due to their potential diagnostic, disease surveillance, and therapeutic applications. While several studies have evaluated EV isolation methods in various biofluids, there are few if any data on these techniques when applied to stool. The latter is an ideal biospecimen for studying EVs and colorectal cancer (CRC) because the release of tumour markers by luminal exfoliation into stool occurs earlier than vascular invasion. Since EV release is a conserved mechanism, bacteria in stool contribute to the overall EV population. In this study, we assessed five EV separation methods (ultracentrifugation [UC], precipitation [EQ‐O, EQ‐TC], size exclusion chromatography [SEC], and ultrafiltration [UF]) for total recovery, reproducibility, purity, RNA composition, and protein expression in stool supernatant. CD63, TSG101, and ompA proteins were present in EV fractions from all methods except UC. Human (18s) and bacterial (16s) rRNA was detected in stool EV preparations. Enzymatic treatment prior to extraction is necessary to avoid non‐vesicular RNA contamination. Ultrafiltration had the highest recovery, RNA, and protein yield. After assessing purity further, SEC was the isolation method of choice. These findings serve as the groundwork for future studies that use high throughput omics technologies to investigate the potential of stool‐derived EVs as a source for novel biomarkers for early CRC detection.

Background: The US Multi-Society Task Force on Colorectal Cancer published guidelines for colonoscopy screening and surveillance in 2008 and affirmed them in 2012. Characteristics associated with guideline adherence among US gastroenterologists have not been assessed. Aim: Assess awareness and adherence of US gastroenterologists with national guidelines for colonoscopy screening and surveillance and predictors of adherence to guidelines. Methods: A Web-based survey was administered to gastroenterologists in various practice settings across the USA. Results: A total of 306 gastroenterologists completed the survey; 86 % reported awareness of the guidelines. Low-volume colonoscopists (<20/month) were less likely to be aware of the guidelines (OR 0.26, p = 0.03) compared to high-volume colonoscopists (>100/month). Those completing training before 1990 were less likely to report following guidelines (OR 0.37, p = 0.01). Adherence with guidelines was then assessed via clinical scenarios. Compared to physicians finishing training in 1991-2010, less adherence was seen in those finishing before 1990 (OR 0.75, p < 0.001) or currently in training (OR 0.72, p = 0.004). Compared to the Western USA, less adherence was seen in the Midwest (OR 0.69, p = 0.001), Northeast (OR 0.63, p < 0.001), and South (OR 0.59, p < 0.001). Lower adherence was seen among non-academic physicians (OR 0.72, p = 0.001) and low-volume colonoscopists (OR 0.52, p < 0.001). Conclusions: There is poor adherence with colonoscopy screening and surveillance guidelines among US gastroenterologists. Poor adherence was associated with being in training or finishing training before 1990, practicing in the South, non-academic settings, and low colonoscopy volume. These findings can target interventions for quality improvement in colorectal cancer screening and surveillance. [ABSTRACT FROM AUTHOR]

Ischemic colitis can mimic a carcinoma on computed tomographic (CT) imaging or endoscopic examination. A coexisting colonic carcinoma or another potentially obstructing lesion has also been described in 20% of the cases of ischemic colitis. CT scan can differentiate it from colon cancer in 75% of cases. However, colonoscopy is the preferred method for diagnosing ischemic colitis as it allows for direct visualization with tissue sampling. Varied presentations of ischemic colitis have been described as an ulcerated or submucosal mass or as a narrowed segment of colon with ulcerated mucosa on colonoscopy. Awareness and early recognition of such varied presentations of a common condition is necessary to differentiate from a colonic carcinoma, and to avoid unnecessary surgery and related complications.