ABSTRACT
Objective To investigate the protective effects of combination alprostadil and dexmedetomidine preconditioning treatment on skeletal muscle ischemia reperfusion and secondary lung injuries.Methods Sixty patients aged less than 70 years old undergoing unilateral lower extremity surgery were randomly assigned into four groups:control group(group A),dexmedetomidine group(group B),alprostadil group(group C)and combined treatment group(group D) with 15 cases in each.In group C and D,10 μg alprostadil was given from vein at 15 min before tourniquet inflation,in group B and D 1 μg/kg dexmedetomidine was given from vein at 10 min before tourniquet inflation,the equal volume of normal saline was infused in control group.The blood samples were drawn from vein and artery for blood gas analysises and determination of malondialdehyde(MDA) and human pulmonary surfactant specific protein D (SP D) concentrations at the time before oxygen inhalation(T1),2 h after tourniquet deflation(T2),6 h after tourniquet deflation(T3) respectively.Results In group B,C and D,the alveolar arterial oxygen pressure difference(PA-a DO2)and respiratory index(R1) were significantly lower than those in group A at T2(P＜0.05).PA-aDO2 and R1 were significantly higher at T3 than those at T1 in every groups(P＜0.05);In group B,C and D,MDA and SP D were significantly lower than those in group A at T2 and T3(P＜0.05).In group D,MDA and SP D were significantly lower than those in group B and group C at T3(P＜0.05).Conclusion Alprostadil and dexmedetomidine are infused from vein preconditioning can attenuate the damages of skeletal muscle ischemia reperfusion and secondary lung injuries.The combination of alprostadil with dexmcdetomidine can produce stronger effects.
ABSTRACT
Objective To construct markless gene deletion mutant at the clpP loci on the chromosome of Streptococcus mutans(S.mutans).Methods ASp resistance gene was amplified by PCR,to construct the Sp resistance cassette where the Sp resistance gene was flanked with two loxP site.After the clpP gene was cloned into the pGEM-T-Easy TA cloning vector,it was digested and linked with the Sp resistance cassette,yielding homologous recombination vector pIB △ clpP-Sp.The vector was linearized and used for the transformation of S.mutans UA159,with transformants selected on TPY plates containing Sp.The selected strain was transformed with the thermosensitive plasmid pCrePA to excise the Sp resistance gene.The pCre-PA was then easily eliminated at nonpermissive temperature,resulting in a markless mutant strain carrying a deletion at the clpP loci,which was verified by PCR and DNA sequencing.Results The result of the PCR analysis and DNA sequencing indicated that a part of the clpP gene was deleted.There was a loxP at this loci without the Sp resistance gene.Conclusion The markless clpP-deletion mutant of S.mutans was constructed successfully,which laid a foundation for further study of its biological function and its influence on the cariogenicity of S.mutans.