A Mouse Model of Targeted Musashi1 Expression in Whole Intestinal Epithelium Suggests Regulatory Roles in Cell Cycle and Stemness

The intestinal epithelium is very peculiar for its continuous cell renewal, fuelled by multipotent stem cells localized within the crypts of Lieberkühn. Several lines of evidence have established the evolutionary conserved RNA-binding protein Musashi1 as a marker of adult stem cells, including those of the intestinal epithelium, and revealed its roles in stem cell self-renewal and cell fate determination. Previous studies from our laboratories have shown that Musashi1 controls stem cell-like features in medulloblastoma, glioblastoma, and breast cancer cells, and has pro-proliferative and pro-tumorigenic properties in intestinal epithelial progenitor cells in vitro. To undertake a detailed study of Musashi1's function in the intestinal epithelium in vivo, we have generated a mouse model, referred to as v-Msi, overexpressing Musashi1 specifically in the entire intestinal epithelium. Compared with wild type litters, v-Msi1 mice exhibited increased intestinal crypt size accompanied by enhanced proliferation. Comparative transcriptomics by RNA-seq revealed Musashi1's association with gut stem cell signature, cell cycle, DNA replication, and drug metabolism. Finally, we identified and validated three novel mRNA targets that are stabilized by Musashi1, Ccnd1 (Cyclin D1), Cdk6, and Sox4. In conclusion, the targeted expression of Musashi1 in the intestinal epithelium in vivo increases the cell proliferation rate and strongly suggests its action on stem cells activity. This is due to the modulation of a complex network of gene functions and pathways including drug metabolism, cell cycle, and DNA synthesis and repair.

Comparison of nasogastric tube securing methods and tube types in medical intensive care patients

BACKGROUND: Nasogastric tube displacement can result in serious complications such as aspiration and inadvertent migration of the tube into the lungs. Replacement of the tubes is costly, time- and effort-intensive, uncomfortable for the patients, and potentially dangerous. OBJECTIVE: To determine the best of three methods for securing nasogastric tubes in a medical intensive care population and to identify variables related to the failure of tube securing methods. METHODS: A convenience sample of 103 patients requiring duodenal or standard gastric tubes for feeding, medication delivery, or decompression were randomly assigned to one of three taping methods: pink tape, clear tape, or "butterfly," for a total of 264 taping episodes. Data collection included the mean time until failure of the securing methods as well as variables such as patient alertness and mobility. RESULTS: The mean time until failure was 100 hours with pink tape versus 56 hours with clear tape and 30 hours with the "butterfly." Differences were significant. Duodenal tubes stayed secured longer than standard sump tubes (mean time until failure was 86 vs 41 hours) for all taping methods, but not significant relationship was demonstrated between mean time until failure and variables such as alertness, sedation, confusion, mobility, and the use of restraints. CONCLUSION: Our results showed that the pink tape method was superior. Nasogastric tube securing methods in adult critical care patients vary in efficacy and should be selected carefully.

Comparison of nasogastric tube securing methods and tube types in medical intensive care patients

BACKGROUND

Nasogastric tube displacement can result in serious complications such as aspiration and inadvertent migration of the tube into the lungs. Replacement of the tubes is costly, time- and effort-intensive, uncomfortable for the patients, and potentially dangerous.

OBJECTIVE

To determine the best of three methods for securing nasogastric tubes in a medical intensive care population and to identify variables related to the failure of tube securing methods.

METHODS

A convenience sample of 103 patients requiring duodenal or standard gastric tubes for feeding, medication delivery, or decompression were randomly assigned to one of three taping methods: pink tape, clear tape, or "butterfly," for a total of 264 taping episodes. Data collection included the mean time until failure of the securing methods as well as variables such as patient alertness and mobility.

RESULTS

The mean time until failure was 100 hours with pink tape versus 56 hours with clear tape and 30 hours with the "butterfly." Differences were significant. Duodenal tubes stayed secured longer than standard sump tubes (mean time until failure was 86 vs 41 hours) for all taping methods, but not significant relationship was demonstrated between mean time until failure and variables such as alertness, sedation, confusion, mobility, and the use of restraints.

CONCLUSION

Our results showed that the pink tape method was superior. Nasogastric tube securing methods in adult critical care patients vary in efficacy and should be selected carefully.