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An impaired intestinal epithelial barrier is thought to be a major factor in the pathogenesis of human inflammatory bowel disease (IBD). IBD is frequently investigated by inducing a damaged barrier in murine models of colitis. This can be done by feeding mice with dextran sulfate sodium (DSS) polymers in their drinking water. Refinement measures should focus on alleviating unnecessary suffering during this probably painful condition. Appropriate parameters are needed to decide when to terminate the experiments. Our aim was to investigate whether a change in burrowing behaviour is a sensitive measure of animal welfare in murine models of colitis. Acute colitis was induced in C57BL/6 mice with 2.0% DSS over nine days. The burrowing test is based on the species-typical behaviour of mice to spontaneously displace items from tubes within their home cage. As a burrowing apparatus, a water bottle (250 mL, 150 mm length, 55 mm diameter) filled with 138–142 g of pellets of the animal’s diet was used. The presence of intestinal inflammation as a result of acute DSS-induced colitis was confirmed by a decrease in body weight, colon length and an increase of murine endoscopic index of colitis severity, histological score and spleen weight in the group receiving DSS as compared with the control group. An onset of intestinal inflammation correlated with a significant decrease in burrowing behaviour (P < 0.05). Altered adrenal gland histology indicated stress as a result of acute colitis. Our findings provide evidence that changes of spontaneous burrowing behaviour correlate with the onset of inflammation in acute DSS-induced colitis. [ABSTRACT FROM AUTHOR]

Ventricular end-diastolic volume (EDV) is an important parameter for monitoring patients with heart pumps, and for informing an algorithm to adapt the pump speed in a smart way. Continuous information on the EDV is unavailable to date. We hypothesize that the depolarization amplitude of the non-contact intra-cardiac electromyogram (iEMG) is physically related to the EDV. Thus, it could serve as a useful measure for predicting EDV in these patients. The study was performed in six pigs while undergoing a series of significant changes in hemodynamic states. Four conventional pacemaker electrodes measured the far-field iEMG inside the left ventricular blood pool, using a novel unipolar amplifier. Simultaneously, measurements of preload and hematocrit were recorded. The proposed EDV predictor was tested for statistical significance using a mixed effect model and associated confidence intervals. A statistically significant (p<0.005) negative correlation was confirmed between the amplitude of the iEMG and the EDV measured by electric impedance at a slope of -0.063 (-0.066, -0.060) mV/mL. The influence of the hematocrit was not found significant. All measurements of the four distinct electrodes yielded comparable results. The amplitude of the iEMG proved a significant, independent predictor of the EDV. Electrodes are simple to integrate into the cannula of a heart pump. Because of their simplicity, electrodes shall be incorporated in the inflow cannula of heart pumps. Given the manifold determinants of the depolarization amplitude, a combination with a mechanical signal, such as pump flow, is likely to further increase robustness. In this way, the iEMG has the potential to inform the clinician about the state of the patient in real-time and to control the pump in a smart way. [ABSTRACT FROM AUTHOR]