AIM: To further investagate the mechanism of thrombus formation and develop a new remedy of anti-thrombus formation. METHODS: The amplified DNA fragment of vWF-A1 domain was inserted into expression vector with 6?his taq (pQE-31), the recombinant expression vect or was transformed into E coli (strain M15) and induced by IPTG. The recombinant fragment, comprising residues 449-728 of mature vWF subunit, designate rvWF-A1. It was purified by Ni-NTA agarose column and renatured by Tris buffer containin g GSH and GSSG. FACS and platelet aggregometer were employed to analyse the rvWF -A1 function of binding to platelet glycoprotein Ib and inhibiting ristocetin-in duced platelet aggregation. RESULTS: The rvWF-A1 was expressed successfully in E coli, comin g up to 30% of total bacterial protein. Its purify was over 95% through Ni-NTA a garose. It was identified to have ability to bind to GPIb, its biologic activity to inhibit ristocetin-induced platelet aggregation was observed, and the inhibi tive rate was 84 7%. CONCLUSION: The above results indicated that high-level expressi on of rvWF-A1 was successfully achieved in E coli and rvWF-A1 may be an effectiv e antithromotic agent in preventing thrombus formation.

Objective To analyze the relationship between the catheter to vein ratio and the formation of peripheral insertion of central venous catheter (PICC) related upper extremity deep venous thrombosis (PICC-UEDVT) in cases having undergone PICC in patients at intensive care unit (ICU) and further identify the best optimal ratio cut-off point to reduce the incidence of PICC-UEDVT.Methods A retrospective study was conducted, including 69 patients having undergone PICC with complete clinical data admitted to the Department of Critical Care Medicine of the First Affiliated Hospital of Nanchang University from August 2013 to December 2016; their ages were > 18 years old and catheter indwelling times were > 1 week; the patients' basic information, disease related laboratory parameters and catheter insertion situation were collected. According to the occurrence of PICC-UEDVT, they were divided into PICC-UEDVT group and non PICC-UEDVT group; the receiver operating characteristic (ROC) curve of the catheter to vein ratio versus the incidence ofPICC-UEDVT was plotted to assess the optimal ratio to reduce the incidence of PICC-UEDVT.Results In the 69 patients, there were 7 patients in the PICC-UEDVT group and 62 patients in the non PICC-UEDVT group, the incidence of PICC-UEDVT being 10.14%. Four, 5 and 6 French (Fr) catheters were indwelled in 43, 23 and 3 cases respectively, and the range of catheter to vein ratio was 20% - 67%. The comparisons between PICC-UEDVT group and non PICC-UEDVT group in various aspects were as follows: the incidence of DVT in the PICC-UEDVT group was significantly higher than that in non PICC-UEDVT group [42.9% (3/7) vs. 6.5% (4/62)], the rate of using vasopressor drugs [57.14% (4/7) vs. 17.74% (11/62)], D-dimer level [mg/L: 9.0 (3.0, 12.3) vs. 1.8 (1.0, 3.6)], patients of indwelling 5Fr catheter [71.4% (5/7) vs. 29.0% (18/62)] and the percentage of patientsapplying catheter to vein ratio 45%-67% [57.14% (4/7) vs. 17.74% (11/62)] in PICC-UEDVT group were all higher than those in the non PICC-UEDVT group, the differences being statistically significant (allP < 0.05). ROC analysis showed that the catheter to vein ratio 44% was the optimal cut off or critical point, the area under the ROC curve (AUC) at that point was 0.755, 95% confidence interval (95%CI) = 0.554-0.955, sensitivity = 71.4% and specificity = 79.0%; compared with the patients using 45%-67% catheter to vein ratio, the incidence of PICC-UEDVT was 6.182 times higher than those using the ratio 20%-44% [odds ratio (OR) = 6.182, 95%CI = 1.208-31.634,P = 0.036]; however, there was no significant difference in incidence of PICC-UEDVT between 20%-32% and 33%-44% (P = 1.000).Conclusion It is found that the 44% catheter to vein ratio was the optimal critical point to reduce the incidence of PICC-UEDVT, possessing relatively high sensitivity and specificity; applying <44% catheter to vein ratio can decrease the risk of PICC-UEDVT occurrence in patients at ICU.

Objective The objective of this study was to investigate the underlying causes of catheter rupture in implantable venous assess ports among 4 paediatric patients and to summarise nursing experiences.Methods A total of 319 implantations of venous assess port were admitted in the Department of Paediatric Surgery of our hospital from March 2011 to January 2023,with an incidence rate of catheter fracture at 1.3%(4 cases).The ruptured catheters in all 4 paediatric patients were successfully retrieved via surgery.The reasons for catheter rupture as well as the methods for identification were analysed and summarised.Results In Case 1,a catheter rupture was located at 6 cm from the port and the ruptured catheter was not displaced.In Case 2,a linear crack was observed at 7 cm from the base of port without visible sign of catheter rupture,however,a leakage was observed from the crack when fluid was injected.In Case 3,the location of catheter rupture was identified at 11 cm from the port and again there was no evidence of displacement.However for Case 4,a catheter rupture occurred at just 1 cm away from the base of port,with a displacement along right atrium-right pulmonary artery-right inferior pulmonary artery.The causes of catheter rupture were attributed to frequent and prolonged neck and upper extremity activities in Cases 1,3 and 4,as well as an inappropriate handling of catheter in Case 2.After removal of the catheter,Cases 1,2 and 4 were kept in hospital for treatment of original illnesses,while Case 3 was discharged the day after the removal of catheter.Conclusion Catheter rupture is an extremely serious complication.It is imperative for healthcare personnel to adhere to standardised procedures and maintenance protocols,together with comprehensive health education to both parents and children.Early detection of an abnormality followed by prompt handling is crucial in ensuring the safety usage of an implantable venous assess port in paediatric patients.

【Objective】 To investigate the clinical characteristics and diagnosis and treatment of passenger lymphocyte syndrome (PLS) in patients following allogeneic hematopoietic stem cell transplantation (allo-HSCT). 【Methods】 A total of 489 patients who underwent allo-HSCT in Suzhou Hongci Hematology Hospital were retrospectively enrolled. The clinical process, diagnosis and treatment measures and prognosis of four patients complicated with PLS after transplantation were analyzed. 【Results】 Among the 489 patients, 4 were diagnosed with PLS. The blood types of donor/recipient ABO were all secondary incompatible (The blood type of donors were O and the recipients were A or B). The overall incidence of PLS in allo-HSCT was 0.82%(4/489)and 2.2%(4/179)in transplants with donor/recipient secondary incompatible ABO-blood types. PLS occured in 6-13 days after donor stem cell infusion. Clinical manifestations were dizziness and fatigue, low back pain, jaundice, deepening urine, rapid decrease in hemoglobin on laboratory tests, elevated indirect bilirubin and lactate dehydrogenase, positive urobilinogen, positive direct anti-human globulin test (DAT), and anti-A or anti-B antibodies against recipient red blood cells were detected in plasma. After the treatment of O-type washed red blood cells, methylprednisolone, gamma globulin, rituximab and other treatments, the hemolysis was improved. All patients achieved engraftment of neutrophil and platelet. Red blood cell transfusion was halted in 3 weeks. 【Conclusion】 PLS is a rare complication of allo-HSCT, which mainly occurs in allo-HSCT patients with secondary incompatibility of ABO blood group of donor/recipient. The clinical prognosis is good after properly treatment.

Objective To investigate the antimicrobial resistance profile of the clinical isolates collected from selected hospitals across China. Methods Twenty-nine general hospitals and five children's hospitals were involved in this program. Antimicrobial susceptibility testing was carried out according to a unified protocol using Kirby-Bauer method or automated systems. Results were interpreted according to CLSI 2017 breakpoints. Results A total of 190 610 clinical isolates were collected from January to December 2017, of which gram negative organisms accounted for 70.8％ (134 951/190 610) and gram positive cocci 29.2％ (55 649/190 610). The prevalence of methicillin-resistant strains was 35.3％ in S. aureus (MRSA) and 80.3％ in coagulase negative Staphylococcus (MRCNS) on average. MR strains showed much higher resistance rates to most of the other antimicrobial agents than MS strains. However, 91.6％ of MRSA strains were still susceptible to trimethoprim-sulfamethoxazole, while 86.2％ of MRCNS strains were susceptible to rifampin. No staphylococcal strains were found resistant to vancomycin. E. faecalis strains showed much lower resistance rates to most of the drugs tested (except chloramphenicol) than E. faecium. Vancomycin-resistant Enterococcus (VRE) was identified in both E. faecalis and E. faecium. The identified VRE strains were mainly vanA, vanB or vanM type based on phenotype or genotype. The proportion of PSSP or PRSP strains in the non-meningitis S.pneumoniae strains isolated from children decreased but the proportion of PISP strains increased when compared to the data of 2016. Enterobacteriaceae strains were still highly susceptible to carbapenems. Overall, less than 10％ of these strains (excluding Klebsiella spp.) were resistant to carbapenems. The prevalence of imipenem-resistant K. pneumoniae increased from 3.0％ in 2005 to 20.9％ in 2017, and meropenem-resistant K. pneumoniae increased from 2.9％ in 2005 to 24.0％ in 2017, more than 8-fold increase. About 66.7％ and 69.3％ of Acinetobacter (A. baumannii accounts for 91.5％) strains were resistant to imipenem and meropenem, respectively. Compared with the data of year 2016, P. aeruginosa strains showed decreasing resistance rate to carbapenems. Conclusions Bacterial resistance is still on the rise. It is necessary to strengthen hospital infection control and stewardship of antimicrobial agents. The communication between laboratorians and clinicians should be further improved in addition to surveillance of bacterial resistance.