Hydrogen gas and preservation of intestinal stem cells in mesenteric ischemia and reperfusion

BACKGROUND Patients with mesenteric ischemia frequently suffer from bowel necrosis even after revascularization.Hydrogen gas has showed promising effects for ischemiareperfusion injury by reducing reactive oxygen species in various animal and clinical studies.We examined intestinal tissue injury by ischemia and reperfusion under continuous initiation of 3%hydrogen gas.AIM To clarify the treatment effects and target cells of hydrogen gas for mesenteric ischemia.METHODS Three rat groups underwent 60-min mesenteric artery occlusion(ischemia),60-min reperfusion following 60-min occlusion(reperfusion),or ischemiareperfusion with the same duration under continuous 3%hydrogen gas inhalation(hydrogen).The distal ileum was harvested.Immunofluorescence staining with caspase-3 and leucine-rich repeat-containing G-protein-coupled 5(LGR5),a specific marker of intestinal stem cell,was conducted to evaluate the injury location and cell types protected by hydrogen.mRNA expressions of LGR5,olfactomedin 4(OLFM4),hairy and enhancer of split 1,Jagged 2,and Neurogenic locus notch homolog protein 1 were measured by quantitative polymerase chain reaction.Tissue oxidative stress was analyzed with immunostaining for 8-hydroxy-2'-deoxyguanosine(8-OHdG).Systemic oxidative stress was evaluated by plasma 8-OHdG.RESULTS Ischemia damaged the epithelial layer at the tip of the villi,whereas reperfusion induced extensive apoptosis of the cells at the crypt base,which were identified as intestinal stem cells with double immunofluorescence stain.Hydrogen mitigated such apoptosis at the crypt base,and the LGR5 expression of the tissues was higher in the hydrogen group than in the reperfusion group.OLFM4 was also relatively higher in the hydrogen group,whereas other measured RNAs were comparable between the groups.8-OHdG concentration was high in the reperfusion group,which was reduced by hydrogen,particularly at the crypt base.Serum 8-OHdG concentrations were relatively higher in both reperfusion and hydrogen groups without significance.CONCLUSION This study demonstrated that hydrogen gas inhalation preserves intestinal stem cells and mitigates oxidative stress caused by mesenteric ischemia and reperfusion.

Evaluating 3D position and velocity of subject in parabolic flight experiment by use of the binocular stereo vision measurement

A practical method for evaluating the three-dimensional（3D） position and velocity of a moving object used in the parabolic flight experiment is developed by using the binocular stereo vision measurement theory. The camera calibration mathematic model without considering the lens distortion is introduced.The direct linear transformation（DLT） algorithm is improved to accomplish the camera calibration.The camera calibration result and optimization algorithm are used to calculate the object＇s world coordinate from image coordinate.The 3D position and the velocity of the moving object are obtained.The standard uncertainty in estimating the velocity is 0.0024 m/s,which corresponds to 1%level of the velocity of the object in the experiment.The results show that this method is very useful for the parabolic flight experiments.

Length of hospital stay and mortality associated with burns from assault:a retrospective study with inverse probability weighting analysis

Background:Burns resulting from assaults account for considerable morbidity and mortality among patients with burn injuries around the world.However,it is still unclear whether unfavorable clinical outcomes are associated primarily with the severity of the injuries.To elucidate the direct relationship between burns resulting from assaults and mortality and/or length of hospital stays,we performed this study with the hypothesis that burns from assault would be independently associated with fewer hospital-free days than would burns from other causes,regardless of the severity of burn injuries.Methods:We conducted a retrospective cohort study,using a city-wide burn registry(1996–2017)accounting for 14 burn centers in Tokyo,Japan.Patients who arrived within 24 hours after injury were included,and those with self-inflicted burn injuries were excluded.Patients were divided into two groups according to mechanism of burns(assault vs.accident),and the number of hospitalfree days until day 30 after injury(a composite of in-hospital death and hospital length of stay)was compared between the groups.To estimate the probability that an injury would be classified as an assault,we calculated propensity scores,using multivariate logistic regression analyses adjusted for known outcome predictors.We also performed an inverse probability weighting(IPW)analysis to compare adjusted numbers of hospital-free days.Results:Of 7419 patients in the registry with burn injuries during the study period,5119 patients were included in this study.Of these,113(2.2%)were injured as a result of assault;they had significantly fewer hospital-free days than did those with burns caused by accident(18[27]vs.24[20]days;coefficient=−3.4[−5.5 to−1.3]days;p=0.001).IPW analyses similarly revealed the independent association between assault burn injury and fewer hospital-free days(adjusted coefficient=−0.6[−1.0 to−0.1]days;p=0.009).Conclusions:Burn from assault was independently associated with fewer hospital-free days,regardless of the severity of burn injuries.The pathophysiological mechanism underlying the relationship should be further studied in a prospective observational study.