Use of butyrate or glutamine in enema solution reduces inflammation and fibrosis in experimental diversion colitis

AIM:To investigate whether butyrate or glutamine enemas could diminish inflammation in experimental diversion colitis.METHODS:Wistar specific pathogen-free rats were submitted to a Hartmann's end colostomy and treated with enemas containing glutamine,butyrate,or saline.Enemas were administered twice a week in the excluded segment of the colon from 4 to 12 wk after the surgical procedure.Follow-up colonoscopy was performed every 4 wk for 12 wk.The effect of treatment was evaluated using video-endoscopic and histologic scores and measuring interleukin-1β,tumor necrosis factor-alpha,and transforming growth factor beta production in organ cultures by enzyme linked immunosorbent assay.RESULTS:Colonoscopies of the diverted segment showed mucosa with hyperemia,increased number of vessels,bleeding and mucus discharge.Treatment with either glutamine or butyrate induced significant reductions in both colonoscopic(P < 0.02) and histological scores(P < 0.01) and restored the densities of collagen fibers in tissue(P = 0.015;P = 0.001),the number of goblet cells(P = 0.021;P = 0.029),and the rate of apoptosis within the epithelium(P = 0.043;P = 0.011) to normal values.The high levels of cytokines in colon explants from rats with diversion colitis significantly decreased to normal values after treatment with butyrate or glutamine.CONCLUSION:The improvement of experimental diversion colitis following glutamine or butyrate enemas highlights the importance of specific luminal nutrients in the homeostasis of the colonic mucosa and supports their utilization for the treatment of human diversion colitis.

Soil Microbial Community Composition During Natural Recovery in the Loess Plateau, China

This study aimed to determine the characteristics of soil microbial community composition and its relationship with soil chemical properties during natural recovery in the Loess Plateau.The soil microbial community composition was analyzed by comparing the soil microbial phospholipid fatty acids（PLFAs） of eight croplands abandoned for 1,3,5,10,13,15,20,and 30 yr in the Dunshan watershed,northern Loess Plateau,China.The results showed that soil organic carbon,total nitrogen,soil microbial biomass carbon,and soil microbial biomass nitrogen significantly increased with the abandonment duration,whereas the metabolic quotient significantly decreased.The Shannon richness and Shannon evenness of PLFAs significantly increased after 10 yr of abandonment.Gram-negative,Gram-positive,bacterial,fungal,and total PLFAs linearly increased with increased abandonment duration.Redundancy analysis showed that the abandonment duration was the most important environmental factor in determining the PLFA microbial community composition.The soil microbial PLFAs changed from anteiso-to iso-,unsaturated to saturated,and short-to long-chain during natural recovery.Therefore,in the Loess Plateau,cropland abandonment for natural recovery resulted in the increase of the soil microbial PLFA biomass and microbial PLFA species and changed the microbial from chemolithotrophic to a more heterotrophic community.

Numerical simulation of foam diversion acidizing in heterogeneous reservoirs

Foam diversion acidizing can effectively solve the problem of acid distribution with severe heterogeneity between and within layers.Based on the foam diversion principle,the gas trap theory,and volume conservation principle,the foam slug diversion acidizing model was established and solved considering the change of bottomhole temperature and deviation factor of foam.The simulation results show that the change of temperature has a great influence on the diversion effect at the initial stage of injection,but a small influence at the middle and late stage.The effect of temperature on the highly permeable layer is greater than that of temperature on the low permeability layer.The deviation factor of foam is mainly controlled by temperature at the initial stage,and by pressure at the middle and late stage,and the whole process shows a downward trend,which has little influence on the diversion effect.The quasi-skin factor of gas trap is the most important parameter that influences the effect of foam diversion.The water saturation of the low permeability layer rises faster than that of the high permeability layer,and the effect of diversion is obvious.The research results have a strong guiding significance for foam diversion acidizing.