Objective To discuss the prevention and treatment of catheter fracture of implantable venous access port (IVAP).Methods A total of 878 adult patients,who received IVAP during the period from January 2012 to December 2012 in a single medical center,were collected.Among the 878 patients,catheter fracture occurred in 7 patients.The clinical data of the 7 patients were retrospectively analyzed.By referring to the related literature,the causes and the prevention measures for catheter fracture were discussed.Results As of November 31,2016,the catheter fracture rate of IVAP,which was implanted via internal jugular vein (IJV),was 0.8％ (7/878).The fracture occurrence time was 855-1412 days after implantation of IVAP,with a mean of 1133 days.The common fracture sites were catheter-IJV junction,catheter-IVAP base joint,and subcutaneous tunnel segment.Conclusion Catheter fracture is one of the serious complications which occur in the course of long-period use of IVAP after its implantation.Standardization of operative procedure,strengthening of the maintenance and nursing education,timely removal of IVAP,and other necessary measures can help reduce the incidence of IVAP catheter fracture and ensure the safety of patients.

Objective To study the effects of Naoxing Nasal Spray(NNS)on ultrastructure of brain tissues i n rats with focal cerebral ischemia -reperfusion inj ury(CIRI ).Methods Thirty Wistar rats were randomly all ocated to 6groups:Group A(treated with high dose of NNS ),Group B(treated with moderate dose of NNS),Group C(treated with low dose of NNS ),Group D(positive control group),Group E (treated with normal saline)and Group F (normal group).After medication for 3days,rat models of CIRI were established by the occlusion of left mid dle cerebral artery.Ultrastructur e of left fore-head cortical tissue was observed un der electron microscope after one -h our ischemia and 24-hour reperfusio n.Results The injury of neurons,gliocytes and capillaries in Group A and Group B was obviously milder than that in Group E and that in Group A was the mildest,the differences being not significant as compared with that in Group D.Conclusion NNS can reduce the ischemic damage of cerebr al cortex and obviously protect cere bral tissues in rats with CIRI.

Emerging SARS-CoV-2 variants have made COVID-19 convalescents susceptible to re-infection and have raised concern about the efficacy of inactivated vaccination in neutralization against emerging variants and antigen-specific B cell response. To this end, a study on a long-term cohort of 208 participants who have recovered from COVID-19 was conducted, and the participants were followed up at 3.3 (Visit 1), 9.2 (Visit 2), and 18.5 (Visit 3) months after SARS-CoV-2 infection. They were classified into three groups (no-vaccination (n = 54), one-dose (n = 62), and two-dose (n = 92) groups) on the basis of the administration of inactivated vaccination. The neutralizing antibody (NAb) titers against the wild-type virus continued to decrease in the no-vaccination group, but they rose significantly in the one-dose and two-dose groups, with the highest NAb titers being observed in the two-dose group at Visit 3. The NAb titers against the Delta variant for the no-vaccination, one-dose, and two-dose groups decreased by 3.3, 1.9, and 2.3 folds relative to the wild-type virus, respectively, and those against the Omicron variant decreased by 7.0, 4.0, and 3.8 folds, respectively. Similarly, the responses of SARS-CoV-2 RBD-specific B cells and memory B cells were boosted by the second vaccine dose. Results showed that the convalescents benefited from the administration of the inactivated vaccine (one or two doses), which enhanced neutralization against highly mutated SARS-CoV-2 variants and memory B cell responses. Two doses of inactivated vaccine among COVID-19 convalescents are therefore recommended for the prevention of the COVID-19 pandemic, and vaccination guidelines and policies need to be updated.