RESUMO
By using a double loop technique based on a set of mechanical transmission components and a flow path system,a double function of injection and fraction collection was realized. On the basis of double loop technique,a novel type of online/offline interface for two-dimensional liquid chromatography was designed to construct an efficient separation system coupling two different separation modes with a higher peak capacity, and the functions of the interface were evaluated. By means of connecting the interface to an HPLC system, the multiple functions of injection, fraction collection and injection again were fulfilled for preparation and purity analysis of 4 kinds of aromatic compounds. As for combination of 2 sets of HPLC system,5 kinds of protein samples were separated preliminarily by strong cation exchange chromatography, and the components difficult to separate were collected and injected into reversed phase chromatographic system for further separation. Furthermore, the interface was applied to coupling two chromatographic systems in both strong cation exchange mode and microcolumn reversed-phase mode for the two-dimensional separation of bovine serum albumin enzymatic digest. When 1 mAU was set as the integral threshold,a total number of 292 peaks were identified. With the help of the online/offline interface, the preparation of microscale samples, fine separation of hardly separated samples and two-dimensional separation of complex samples were achieved flexibly. The result indicated that the system was a potent tool for the construction of two-dimensional chromatographic system and separation research.
RESUMO
AIM:To investigate the effects of dexmedetomidine on hemorrhagic shock /resuscitation(HS/R)-induced acute kidney injury(AKI)in rats,and to explore the possible mechanisms.METHODS:Wistar rats(n=32) were randomly divided into 4 groups(n =8): normal saline control group(NS group), dexmedetomidine group(D group),HS/R group and HS/R+D group.The animals were sacrificed at 6 h after resuscitation.The levels of serum creatinine(Cr)and blood urine nitrogen(BUN)were examined.The kidneys of all rats were removed for evaluation of histological characteristics,and the levels of malondialdehyde(MDA),tumor necrosis factor-α(TNF-α),interleukin-1β (IL-1β)and superoxide dismutase(SOD)were measured.The expression of nuclear factor-κB(NF-κB)and hemeoxyge-nase-1(HO-1)was determined by Western blot.RESULTS: Compared with NS group, the levels of Cr, BUN, MDA, TNF-αand IL-1βwere obviously increased in HS/R group, which were obviously decreased in HS/R+D group(P<0.05).Compared with NS group,the SOD activity was obviously decreased in HS/R group,which was obviously increased in HS/R+D group(P<0.05).Compared with NS group, the protein expression of NF-κB was obviously increased in HS/R group,which was obviously decreased in HS/R+D group(P<0.05).Compared with NS group, the protein ex-pression of HO-1 was increased in HS/R group.Compared with HS/R group,the protein expression of HO-1 was obviously increased in HS/R+D group.Compared with NS group,HS/R induced marked kidney histological injury,which was less pronounced in HS/R+D group.CONCLUSION:Dexmedetomidine effectively protects rats against AKI caused by HS /R, and its mechanism may be associated with the increase in HO-1 expression and the inhibition of NF-κB expression.