Objective To construct the prokaryotic expression vector of human procalcitonin(PCT) and obtain the highly purified recombinant PCT protein.Methods PCT primers were designed based on the sequence of PCT gene from NCBI,and PCT gene was amplified by PCR.Then,the recombinant vector PCT/pET-22b(+) was constructed and transferred into E.coli BL21 to induce the expression of recombinant PCT protein.Last,the recombinant PCT protein was purified by the nickel column affinity chromatography and identified by Western blot and the colloidal gold method,respectively.Results The results of agarose gel electrophoresis showed that the product of PCR amplification was about 350 bp.The homology comparison analysis revealed that the PCT gene fragment(348 bp) was successfully inserted into pTG19-T vector,and that no any base mutation was found.When the recombinant plasmid of PCT/pET-22b(+) was digested with BamH Ⅰ and HindⅢ,two pieces of about 350 bp and 5 500 bp were obtained.SDS-PAGE showed that the recombinant PCT protein with about 14 000 of Mr was existed in soluble form,and was easily obtained by the nickel column affinity chromatography.Moreover,western blot and the colloidal gold method demonstrated that the recombinant PCT protein was successfully expressed and contained histidine label(His-tag).Conclusion The recombinant vector PCT/pET-22b(+) is successfully constructed by the recombinant DNA technology,and the recombinant PCT fusion protein is successfully obtained by the nickel column affinity chromatography.

Objective To explore the assisted reproductive strategy and influencing factors for patients undergoing frozen-thawed cycle blastocyst transfer after hysteroscopic adhesiolysis for intrauterine adhesions.Methods A total of 275 patients who underwent frozen-thawed cycle blastocyst transfer after hysteroscopic adhesiolysis for infertility reasons at the Reproductive Genetics Center of the First Affiliated Hospital of University of Science and Technology of China from January 2018 to December 2022 were included in the study.They were divided into a single blastocyst transfer group(n=182)and a double blastocyst transfer group(n=93).The clinical outcomes were analyzed and compared retrospectively between the group.Results The two groups showed no statis-tically significant differences in terms of age,day of endometrial thickness conversion,endometrial preparation method,clinical pregnancy rate,miscarriage rate,preterm birth rate,gestational week at delivery,and mode of delivery(P>0.05).The single blastocyst transfer group had significantly lower infertility duration(years)(2.43±1.64 vs.3.03±2.13,P<0.05),significantly lower AFS prognosis score(5.13±2.25 vs.5.72±2.19,P<0.05),and significantly lower multiple pregnancy rate(1.33%vs.28.57%,P<0.05),but significantly higher quality embryo rate(90.66%vs.46.24%,P<0.05),implantation rate(50.00%vs.34.41%,P<0.05),and live infant mass(g)(3236.84±565.35 vs.2976.44±692.79,P<0.05)compared to the double blastocyst transfer group.Binary logistic regression analysis showed that the number of high-quality embryos transferred and AFS score were independent influencing factors for clinical pregnancy(P<0.05).Conclusions The number of high-quality embryos transferred and the AFS score are independent influencing factors for clinical pregnancy in patients undergoing frozen-thawed cycle blastocyst transfer after hysteroscopic adhesiolysis for intrauterine adhesions.Single high-quality blastocyst transfer is a preferred treatment for patients after hysteroscopic adhesiolysis,and double blastocyst transfer is favor-able for patients with a poor prognosis to achieve better pregnancy outcomes.