Objective To investigate the efficacy of discontinuous density gradient combined with swim-up method for bacterial removal in frozen semen,and to provide experimental evidence for the safe application of frozen semen in assisted reproductive technology.Methods A total of 208 frozen semen samples containing non-pathogenic bacteria,cryopreserved in our human sperm bank from January 2019 to December 2023,were selected.The thawed semen samples were processed using discontinuous density gradient combined with swim-up method.To simulate in vitro fertilization procedures,the processed sperm suspensions were subjected to 5-day in vitro culture for bacterial residue monitoring.Prior to cryopreservation,all semen samples underwent routine bacterial culture to exclude pathogenic microorganisms.Post-thaw semen samples,processed sperm suspensions,and 5-day culture media were sent to an independent third-party laboratory for comprehensive bacterial identification.Results Among the 208 frozen semen samples containing non-pathogenic bacteria,41 bacterial species were identified,with 1～4 species per sample.After processing with discontinuous density gradient combined with swim-up method,the sterility rate of the sperm suspension reached 89.42%(186/208),with residual bacteria including Enterococcus faecalis,Corynebacterium glucuronolyticum,Group B Streptococcus,and Corynebacterium glycinophilum.After 5-day in vitro culture,the sterility rate increased to 93.75%(195/208),with residual bacteria limited to Entero-coccus faecalis and Group B Streptococcus.Conclusions The combined method of discontinuous density gradient and swim-up technique effectively eliminates most bacteria in frozen semen.However,the clearance rate for Entero-coccus faecalis and Group B Streptococcus remains below 90%.Optimization of pre-freezing bacterial screening and post-thaw processing techniques is necessary to enhance the safety of frozen semen in assisted reproductive technology.

Objective To investigate the efficacy of discontinuous density gradient combined with swim-up method for bacterial removal in frozen semen,and to provide experimental evidence for the safe application of frozen semen in assisted reproductive technology.Methods A total of 208 frozen semen samples containing non-pathogenic bacteria,cryopreserved in our human sperm bank from January 2019 to December 2023,were selected.The thawed semen samples were processed using discontinuous density gradient combined with swim-up method.To simulate in vitro fertilization procedures,the processed sperm suspensions were subjected to 5-day in vitro culture for bacterial residue monitoring.Prior to cryopreservation,all semen samples underwent routine bacterial culture to exclude pathogenic microorganisms.Post-thaw semen samples,processed sperm suspensions,and 5-day culture media were sent to an independent third-party laboratory for comprehensive bacterial identification.Results Among the 208 frozen semen samples containing non-pathogenic bacteria,41 bacterial species were identified,with 1～4 species per sample.After processing with discontinuous density gradient combined with swim-up method,the sterility rate of the sperm suspension reached 89.42%(186/208),with residual bacteria including Enterococcus faecalis,Corynebacterium glucuronolyticum,Group B Streptococcus,and Corynebacterium glycinophilum.After 5-day in vitro culture,the sterility rate increased to 93.75%(195/208),with residual bacteria limited to Entero-coccus faecalis and Group B Streptococcus.Conclusions The combined method of discontinuous density gradient and swim-up technique effectively eliminates most bacteria in frozen semen.However,the clearance rate for Entero-coccus faecalis and Group B Streptococcus remains below 90%.Optimization of pre-freezing bacterial screening and post-thaw processing techniques is necessary to enhance the safety of frozen semen in assisted reproductive technology.

Peripherally inserted central catheter (PICC) has the advantages of long-term indwelling, avoiding repeated puncture and effectively protecting peripheral blood vessels, and has been widely used in various clinical fields. The correct position of the PICC tip is an important guarantee for the safe use of catheter. If malposition occurs, it will shorten the catheter indwelling time, increase the incidence of complications, and even life-threatening in severe cases. This article summarizes the methods of PICC tip positioning and the related factors of malposition. In this article, in addition to conventional positioning methods, new positioning techniques such as Sherlock 3CG tip confirmation system and VasoNova vascular positioning system (VPS) combined with electrocardiogram (ECG) are proposed. This article points out that factors such as vascular factors, respiratory motion and intrathoracic pressure changes can lead to changes in the position of the PICC tip, in order to provide a reference for clinical medical and nursing staff to determine the position of the catheter tip and prevent catheter tip malposition.

The catheter self-management ability of carcinoma patients undergoing peripherally inserted central catheter (PICC) is closely related to the incidence of catheter complications. The lower the self-management level, the higher the incidence of catheter-related complications and adverse events. This paper mainly reviews the status quo, influencing factors, improvement approaches and evaluation methods of catheter self-management ability of carcinoma patients undergoing PICC so as to provide a reference for clinical medical staff to help carcinoma patients undergoing PICC improve catheter self-management abilities.