Objective To investigate the conformational states of ADAMTS13 under different pH conditions.Methods Atomic force microscopy(AFM)was applied to pull ADAMTS13 molecules with two distinct pulling systems:the Biotin-Streptavidin system and the 6×His-Anti-His antibody system.The rupture forces and molecular contour lengths were analyzed.Results Under pH 7.4 condition,when ADAMTS13 was pulled by Biotin-Streptavidin system,the mean molecular contour length was(30.93±1.56)nm,exhibiting a bimodal frequency distribution with peak positions at(22.12±0.01)and(49.57±0.05)nm.When ADAMTS13 was pulled using 6×Hist-anti-His antibody system,the mean molecular contour length was(32.77±0.72)nm,also showing a bimodal distribution,with a peak position at(25.73±0.16)and(43.84±0.63)nm,respectively.Under pH 6.0 condition,when ADAMTS13 was pulled by Biotin-Streptavidin system,the mean molecular contour length increased to(47.07±1.6)nm,and the frequency distribution shifted to trimodal,with peak positions at(22±1.25),(55.09±2.62)and(76.69±3.06)nm.The conformation of ADAMTS13 was more extended at pH 6.0 compared with that at pH 7.4.Conclusions ADAMTS13 exists in'closed'and intermediate conformational states at physiological pH 7.4.However,at pH 6.0,ADAMTS13 can adopt'closed',intermediate,and'open'conformational states.This study contributes to a further understanding of the role of ADAMTS13 in normal physiology and thrombotic thrombocytopenic purpura,providing insights for the development of novel recombination ADAMTS13 drugs.

Objective To investigate the conformational states of ADAMTS13 under different pH conditions.Methods Atomic force microscopy(AFM)was applied to pull ADAMTS13 molecules with two distinct pulling systems:the Biotin-Streptavidin system and the 6×His-Anti-His antibody system.The rupture forces and molecular contour lengths were analyzed.Results Under pH 7.4 condition,when ADAMTS13 was pulled by Biotin-Streptavidin system,the mean molecular contour length was(30.93±1.56)nm,exhibiting a bimodal frequency distribution with peak positions at(22.12±0.01)and(49.57±0.05)nm.When ADAMTS13 was pulled using 6×Hist-anti-His antibody system,the mean molecular contour length was(32.77±0.72)nm,also showing a bimodal distribution,with a peak position at(25.73±0.16)and(43.84±0.63)nm,respectively.Under pH 6.0 condition,when ADAMTS13 was pulled by Biotin-Streptavidin system,the mean molecular contour length increased to(47.07±1.6)nm,and the frequency distribution shifted to trimodal,with peak positions at(22±1.25),(55.09±2.62)and(76.69±3.06)nm.The conformation of ADAMTS13 was more extended at pH 6.0 compared with that at pH 7.4.Conclusions ADAMTS13 exists in'closed'and intermediate conformational states at physiological pH 7.4.However,at pH 6.0,ADAMTS13 can adopt'closed',intermediate,and'open'conformational states.This study contributes to a further understanding of the role of ADAMTS13 in normal physiology and thrombotic thrombocytopenic purpura,providing insights for the development of novel recombination ADAMTS13 drugs.

Objective:To evaluate and summarize the relevant evidence on skin flap management in patients with breast cancer after mastectomy at home and abroad.Methods:Domestic and foreign clinical decision-making systems, guideline websites, professional societies websites, evidence-based databases, and original research databases were systematically searched for clinical practice guidelines, expert consensus, evidence summary and systematic evaluation on skin flap management in patients with breast cancer after mastectomy. The retrieval period was from January 2010 to April 2020. Two researchers with evidence-based nursing knowledge independently screened the search results and evaluated the quality.Results:A total of 24 articles were included, including 17 systematic reviews, 2 evidence summaries, 3 expert consensus and 2 clinical decisions. The 17 best pieces of evidence were summarized from three aspects, including preoperative, intraoperative and postoperative management.Conclusions:Existing evidence covers the three aspects of preoperative, intraoperative and postoperative management. In clinical applications, system changes should be taken as the main entry point to realize the transformation of evidence to the clinic, so as to reduce the occurrence of postoperative flap complications, increase patient satisfaction, improve the quality of nursing and reduce medical costs.

The Doha Declaration has entrusted to the members of WHO the right to use the compulsory licensing for drug patents in the face of global public health crises.Although the basic compulsory licensing system for drug patents has been established in China, the efficiency of its implementation is low, the responsibility of its executive departments is unclear, the related rules are not fully understood by pharmaceutical enterprises, it is thus necessary to improve and perfect the relevant legal provisions and systems in order to effectively improve the accessibility of drugs.