The amino-terminal pro-C-type natriuretic peptide(NT-proCNP)is a diagnostic inflam-matory marker clinically used for diagnosing bacterial infections.This study aims to establish a phage display library of single-chain variable fragment(scFv)antibodies against canine NT-proC-NP and to screen for scFvs with high binding affinity to NT-proCNP.Initially,NT-proCNP was prepared using prokaryotic expression system and was used to immunize New Zealand White rab-bits.Upon achieving the desired serum titer,total RNA was extracted from the splenocytes of rab-bits and reverse transcribed into cDNA.Using this cDNA as a template,degenerate primers were employed to amplify the genes of the rabbit antibody light chain variable region(VL)and heavy chain variable region(VH).The VL and VH regions were spliced together to form a complete scFv fragment via overlap extension PCR.The scFv was then ligated into the phagemid pComb3XSS and electroporated into competent E.coli TG1 cells to construct a rabbit-derived anti-NT-proCNP scFv immunological library.This library underwent four rounds of enrichment and screening to isolate specific single-chain antibodies.The selected antibody was subsequently ex-pressed in a soluble form within a prokaryotic system,and its immunological activity was evalua-ted.Using phage display technology,this study successfully identified a single-chain antibody scFv-1-CNP with strong antigen-binding activity and genetic sequence characteristics of scFvs,providing a research direction for further exploration of scFv applications in the detection of NT-proCNP.

The amino-terminal pro-C-type natriuretic peptide(NT-proCNP)is a diagnostic inflam-matory marker clinically used for diagnosing bacterial infections.This study aims to establish a phage display library of single-chain variable fragment(scFv)antibodies against canine NT-proC-NP and to screen for scFvs with high binding affinity to NT-proCNP.Initially,NT-proCNP was prepared using prokaryotic expression system and was used to immunize New Zealand White rab-bits.Upon achieving the desired serum titer,total RNA was extracted from the splenocytes of rab-bits and reverse transcribed into cDNA.Using this cDNA as a template,degenerate primers were employed to amplify the genes of the rabbit antibody light chain variable region(VL)and heavy chain variable region(VH).The VL and VH regions were spliced together to form a complete scFv fragment via overlap extension PCR.The scFv was then ligated into the phagemid pComb3XSS and electroporated into competent E.coli TG1 cells to construct a rabbit-derived anti-NT-proCNP scFv immunological library.This library underwent four rounds of enrichment and screening to isolate specific single-chain antibodies.The selected antibody was subsequently ex-pressed in a soluble form within a prokaryotic system,and its immunological activity was evalua-ted.Using phage display technology,this study successfully identified a single-chain antibody scFv-1-CNP with strong antigen-binding activity and genetic sequence characteristics of scFvs,providing a research direction for further exploration of scFv applications in the detection of NT-proCNP.

Objective To evaluate the effectiveness of Percu Twist (PT) tracheostomy comparing with that of operative tracheostomy(OT)in intensive care unit(ICU). Methods Related data were retrieved from CBM,CNKI,Wanfang Data,VIP,PubMed,EMBASE,CENTRAL,and Web of Science from the time of their establishment to May 15th 2014,and the data of randomized controlled trials(RCTs)concerning PT and OT were selected. The risk of bias assessment and data extraction were performed by two independent reviewers. Meta analysis was conducted using RevMan 5.2 software. Results A total of 12 RCTs were identified,and 893 patients in ICU were involved. The results of Meta-analysis showed that PT could significantly shorten the operation time〔mean difference (MD)=-15.11,95% confidence interval(95%CI)=-17.14 to -13.07,P<0.000 01〕,reduce the volume of blood loss(MD=-17.59,95%CI=-21.90 to-13.28,P<0.000 01),reduce the size of incision(MD=-2.20, 95%CI=-2.57 to -1.82,P<0.000 01),shor ten the time of healing(MD=-3.60,95%CI=-4.15 to -3.05, P<0.000 01),and reduce complications such as infection of the wound〔odds ratio(OR)=0.20,95%CI=0.10-0.44,P<0.000 1〕and cutaneous emphysema/mediastinal emphysema(OR=0.22,95%CI=0.10-0.47,P<0.000 1)compared with OT group. The funnel plot suggested that publication bias might be found among 12 researches. Conclusions PT was shown to be more effective than OT in ICU with lower incidence of complications. As number of RCT cases is still small with unsatis factory quality,further clinical use is warranted for a better assessment.