BACKGROUND:Periprosthetic fracture of the femoral of the knee after total knee arthroplasty is one of the common complications,and there is a lack of biomechanical research on the periprosthetic fractures of the femoral of the knee under different bone strength conditions.The three-dimensional finite element analysis can provide a biomechanical basis for clinical practice. OBJECTIVE:To investigate the biomechanical changes of anterior femoral notching after total knee arthroplasty under different bone strengths,and to provide a mechanical basis for the clinical prevention of supracondylar femoral periprosthetic fractures after knee arthroplasty. METHODS:The femoral CT data of healthy adults were obtained,and the three-dimensional model of femoral lateral replacement of the knee joint was established by Mimics,Geomagic studio,and Solidworks software.Anterior femoral notching models of different depths were constructed,and the models were imported into ANSYS software to analyze the changes of biological stress on the femoral condyle with different bone strengths and different anterior femoral notching depths.The stress changes of the femoral anterior condyle section after and before the filling of anterior femoral notching with bone cement were analyzed. RESULTS AND CONCLUSION:(1)Under any bone strength,the supracondylar stress increased with the depth of anterior femoral notching.In normal bone conditions,there was a stress abrupt change point when the anterior femoral notching depth was between 3 mm and 4 mm.In the case of osteoporosis,there was a stress abrupt point when the anterior femoral notching depth was between 2 mm and 3 mm.(2)When anterior femoral notching occurred during knee arthroplasty and the depth exceeded the thickness of the bone cortex,the supracondylar stress of the femoral gradually increased as the bone strength decreased.(3)The stress of the anterior femoral condyle section decreased when the model with an anterior femoral notching depth of 3 mm was filled with bone cement.(4)The results show that anterior femoral notching should be avoided during knee arthroplasty,especially in patients with osteoporosis.If anterior femoral notching occurs during surgery,bone cement can be used to evenly fill the anterior femoral notching to reduce the supracondylar stress of the femur and reduce the incidence of periprosthetic fractures of the femoral joint

Objective:To prepare the anti-programmed death-ligand 1 (PD-L1) nanoantibody P3C8-C3Fab by ligating with C3Fab and to investigate its role in plasma half-life.Methods:The C3Fab peptide derived from protein G was molecularly fused with the nanobody P3C8 by DNA recombination technology. The nanoantibody P3C8-C3Fab was inducibly expressed and purified in the E. coli BL21 strain, and the binding of it to PD-L1 protein, mouse IgG, and PD-L1-expressing tumor cells was detected by enzyme-linked immunosorbent assay (ELISA). The residual P3C8-C3Fab was detected in mouse serum at different times using double-antibody sandwich ELISA to assess the prolongation of the plasma half-life of PD-L1 nanobodies by C3Fab. Results:The nanoantibody P3C8-C3Fab was successfully constructed, and it could efficiently express itself in soluble form in BL21. The purified NbP3C8-C3Fab protein was obtained with a mass fraction of about 90% at a yield of 7.18 mg/L. The affinity of P3C8-C3Fab for PD-L1 protein and mouse IgG gradually increased with increasing mass concentration and showed a concentration correlation. The binding of P3C8-C3Fab to lung cancer A549 cells showed a concentration correlation. The concentration standard curve of P3C8-C3Fab in mouse serum showed a typical S-shape with a concentration correlation. The plasma half-life of P3C8 was only 0.44 h, while the plasma half-life of P3C8-C3Fab was 21.27-fold higher, up to 9.36 h.Conclusions:The linkage of C3Fab to the nanobodies of P3C8 can significantly prolong the plasma half-life of P3C8, which is valuable for the improvement of in vivo nanobody effects.

Objective:To explore the early coagulation function changes of penetrating intestinal firearm injury of pig in high-altitude environments.Methods:Twenty healthy long white piglets were selected and divided into the plain group and the high-altitude group using the random number table method, with 10 pigs in each group. Pigs in the plain group were placed in a plain environment at an altitude of 800 meters, while pigs in the high-altitude group were placed in an experimental chamber simulating an altitude of 6 000 meters for 48 hours. Both groups received pistol gunshot to have firearm penetrating wounds to the abdominal intestinal tract and then returned to the plain observation room. At 0, 2, 4, 8, 12 and 24 hours after injury, coagulation in the peripheral blood and fibrinolytic indexes [prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), fibrinogen (Fbg), D-dimer (D-D), and fibrinogen degradation product (FDP)], thromboelastogram (TEG) [reaction time (R), clotting time (K), clot formation rate (α), maximum amplitude (MA) and coagulation composite index (CI) ], platelet parameters [platelet count (PLT), mean platelet volume (MPV), platelet distribution width (PDW), and platelet-large cell ratio (P-LCR)] in the two groups were detected separately.Results:The PT values at 0 and 2 hours after injury in the high-altitude group were significantly lower than those in the plain group, while they were significantly higher at 8, 12 and 24 hours than those in the plain group ( P<0.01); there was no significant difference at 4 hours between the two groups ( P>0.05). The APTT values at 0, 2 and 4 hours after injury in the high-altitude group were significantly lower than those in the plain group, while they were significantly higher at 8, 12 and 24 hours after injury than those in the plain group ( P<0.01). The TT values at 0, 2 and 4 hours after the injury in the high-altitude group were significantly lower than those in the plain group, while they were significantly higher at 12 and 24 hours after injury than those in the plain group ( P<0.01); there was no significant difference at 8 hours after injury between the two groups ( P>0.05). The Fbg, D-D and FDP values at 0, 2, 4, 8, 12 and 24 hours after injury were higher in the high-altitude group than those in the plain group ( P<0.01). The R values at 0, 2 and 4 hours after injury in the high-altitude group were significantly lower than those in the plain group, while they were significantly higher at 8, 12 and 24 hours after injury than those in the plain group ( P<0.01). The K values at 0, 2, 4 and 8 hours after injury in the high-altitude group were significantly lower than those in the plain group, while they were significantly higher at 12 and 24 hours after injury than those in the plain group ( P<0.05 or 0.01). The α angles at 0, 2 and 4 hours after injury in the high-altitude group were significantly higher than those in the plain group, while they were significantly lower at 8, 12 and 24 hours after injury than those in the plain group ( P<0.01). The MA values at 0, 2 and 4 hours after the injury in the high-altitude group were significantly higher than those in the plain group, while they were significantly lower at 8, 12 and 24 hours after injury than those in the plain group ( P<0.01). The CI values at 0, 2 and 4 hours after injury in the high-altitude group were significantly higher than those in the plain group, while they were significantly lower at 8, 12 and 24 hours after injury than those in the plain group ( P<0.01). The PLT values at 0, 2, 4 and 8 hours after injury in the high-altitude group were significantly higher than those in the plain group, while they were significantly lower at 12 and 24 hours after injury than those in the plain group ( P<0.05 or 0.01). The MPV values at 0, 2, 4, 8, 12 and 24 hours after injury in the high-altitude group were significantly higher than those in the plain group ( P<0.01). The PDW values at 2, 4, 8, 12 and 24 hours after injury in the high-altitude group were significantly higher than those in the plain group ( P<0.05 or 0.01), while there was no significant difference in PDW at 0 hour after injury between the two groups ( P>0.05). The P-LCR values at 0, 2, 4, 8, 12 and 24 hours after injury in the high-altitude group were all significantly higher than those in the plain group ( P<0.01). Conclusion:Compared with the plain environments, pig intestinal firearm penetrating injury in the high-altitude environments is more prone to early hypercoagulable state accompanied by mild hyperfibrinolysis, and faster to reach a hypocoagulable state accompanied by obvious hyperfibrinolysis.

Objective To observe the changes to,and possible mechanism of,intestinal permeability in pigs without direct injury after an abdominal-and intestinal-penetrating injury from firearms in cold environment at high altitudes.Methods Fifty-five experimental pigs were divided into two groups:high-altitude cold group(HC)and low-altitude normal temperature group(LN).According to the observation time,each group was divided into five experimental subgroups:0h,2h,4 h,8h,and 24 h.There were six pigs in each HC subgroup and five pigs in each LN subgroup.After euthanasia,intestinal tissues were taken,and the levels of the inflammatory factors TNF-α,and IL-6 in intestinal homogenate and the concentrations of intestinal permeability-related proteins DAO and D-lactate acid in blood were detected by ELISA method.The intestinal tissues of experimental pigs were taken at 0 h and 8 h for LN and 8 h for HC,and intestinal pathological changes were observed and scored after HE staining.The concentrations of Occludin,ZO-1,Claudin-3,TLR4,NF-κB,and MLCK(proteins related to intestinal permeability)were detected by Western blot to explore the effect of a cold environment at high altitude on secondary intestinal permeability changes after injury and the possible mechanisms.Results Both the HC group and LN group experienced typical abdominal intestinal penetrating injuries,and there were no significant differences in their abdominal infection scores or intestinal adhesion(P＞0.05).The levels of DAO and D-LA in the serum of experimental pigs in the HC and LN groups gradually increased over time.The levels of DAO and D-LA in the HC group were significantly higher than those in the LN group at all time points(P＜0.01 or P＜0.001).The fastest increase in DAO and D-LA in the HC group was 4 h to 8 h,while in the LN group,it was 8 h to 24 h.The pathological score of intestinal tissue in the HC group was significantly higher than that in the LN group of experimental pigs(P＜0.01).The inflammatory factors TNF-α and IL-6 both increased over time in the intestinal tissue of LN and HC groups.The most significant time point for a increase of inflammatory factors in the HC group was 4 h to 8 h,while in the LN group,it was 8 h to 24 h.The intestinal tissue IL-6 and TNF-α levels of experimental pigs in the HC group were higher than those in the LN group the entire time(P＜0.05,P＜0.01,or P＜0.001).The levels of occludin and ZO-1 in the HC group at 8 h decreased significantly compared to those of the LN group at the 8 h time point(P＜0.05),while claudin-3 showed a significant decrease in LN(P＜0.001).In the HC group,TLR4,NF-κB,and MLCK were both higher than those in the LN group at 8 h,and the difference was statistically significant(P＜0.05).Conclusions A high-altitude cold environment can lead to a secondary increase in intestinal permeability after abdominal-penetrating firearm injury,and its mechanism may be related to the TLR4/NF-κB/MLCK pathway.

Surgical resection and radiotherapy have been commonly applied to the treatment of early- and intermediate-stage Merkel cell carcinoma. In recent years, immunotherapy based on immunogenic characteristics of Merkel cell carcinoma has been proved to be effective in the treatment of advanced Merkel cell carcinoma. This review focuses on advances in the treatment of Merkel cell carcinoma, and provides a reference for its clinical diagnosis and treatment.

Kidney is a highly vascularized organ and peritubular capillary network constitutes the critical component of its microvascular system. Peritubular capillaries, as the main vessels for blood supply in renal tubules and renal interstitium, involve in important physiological processes in renal tubules such as energy metabolism, substance secretion and reabsorption. In recent years, it has been demonstrated that ischemia-reperfusion injury, rejection and renal fibrosis during kidney transplantation would result in compromised structural integrity and decreased number in peritubular capillaries, thus leading to interstitial fibrosis in renal allograft, which would seriously affect the long-term stability of renal function in the renal allograft. Therefore, we reviewed the structure and function of peritubular capillary, peritubular capillary and ischemia-reperfusion injury, rejection and renal allograft fibrosis, focusing on the mechanism for peritubular capillary injury in kidney transplantation and the specific changes manifested, with the aim of providing a reference for preventing and treating perioperative complications in kidney transplantation and improving the long-term prognosis of grafts.

The review focused upon the molecular mechanisms underlying ischemia reperfusion injury leading to interstitial fibrosis in transplanted kidneys, the roles of vascular dysfunction, epithelial cells, and pericytes in this process, the construction of different animal experimental models and their effects and recent novel approaches for the prevention and treatment of this process.

Objective:To explore the clinical efficacy of treating external iliac artery dissection in renal transplantation by artificial vascular replacement.Methods:Four sudden intraoperative cases of external iliac artery dissection were selected.After removing vascular sutures, intimal arterial peeling blocked external iliac artery( n=3)and transplanted renal artery( n=1). Artificial vascular replacement of external iliac artery was performed using artificial vessels made from puffed polytetrafluoride ethylene(ePTFE). Secondary perfusion was performed in four transplanted kidneys for anastomosing with internal iliac artery. Results:One patient regained normal renal function within 1 week post-operation.Two cases had delayed graft function.Another case had delayed graft function plus acute rejection.After hemodialysis, renal function normalized at 2-3 weeks post-operation.During a follow-up period of(0.5-5.0)years, transplanted kidney function remained stable, blood supply, skin temperature and movement of operated lower extremities normalized.Conclusions:The incidence of vascular dissection of external iliac artery is not high during renal transplantation.However, the disease has a rapid and dangerous progression.The consequences of delayed intervention are quite serious.Treating external iliac artery dissection with renal transplantation may achieve satisfactory clinical outcomes.

Objective:To establish the biology reference interval (RI) of peripheral blood procalcitonin (PCT) for children between 3 days and 6 years old in China.Methods:Totally 3 353 reference individuals with apparent health or no specific diseases were recruited in 18 hospitals throughout the country during October 2020 to May 2021. Reference individuals were divided into four groups: 3-28 days, 29 days - 1 year, 1-3 years and 4-6 years. Vein blood or capillary blood were collected by percutaneous puncture from every reference individual. The PCT level in serum and the capillary whole blood were assayed by Roche Cobas e601 and Norman NRM411-S7 immunoanalyzer. Outliers were deleted and 95th percentiles of every group were provided as RIs. Man-Whitney U test or Kruskal-Wallis test were used performed to assess the difference among different gender, age or method groups. Results:The difference of PCT distribution between male and female is not statistically significant, but the difference between serum and capillary whole blood is statistically significant. The differences between age groups are significant too. For Roche e601, serum PCT RI of 3-28 days group is <0.23 μg/L, 29 days - 6 years are <0.11 μg/L. For NRM411, Serum PCT RI of 3-28 days group is <0.21 μg/L, 29 days - 1 year: <0.09 μg/L, 1 - 6 years: <0.10 μg/L. For whole blood PCT, RI of 3-28 days group is <0.26 μg/L, 29 days - 6 years is <0.15 μg/L.Conclusions:Serum and capillary whole blood PCT have different RIs, however, capillary whole blood PCT testing is valuable in pediatric application. Children in 3-28 days show higher PCT levels than other age group. To establish the RIs and understand the differences among different groups are essential for the interpretation and clinical application of peripheral blood PCT testing results.

Objective: This study aimed to estimate the clinical effects of different types of bone-anchored maxillary protraction devices by using a network meta-analysis. Methods: We searched seven databases for randomized and controlled clinical trials that compared bone-anchored maxillary protraction with tooth-anchored maxillary protraction interventions or untreated groups up to May 2021. After literature selection, data extraction, and quality assessment, we calculated the mean differences, 95% confidence intervals, and surface under the cumulative ranking scores of eleven indicators. Statistical analysis was performed using R statistical software with the GeMTC package based on the Bayesian framework. Results: Six interventions and 667 patients were involved in 18 studies. In comparison with the tooth-anchored groups, the bone-anchored groups showed significantly more increases in Sella-Nasion-Subspinale (°), Subspinale-Nasion-Supramentale(°) and significantly fewer increases in mandibular plane angle and the labial proclination angle of upper incisors. In comparison with the control group, Sella-NasionSupramentale(°) decreased without any statistical significance in all treated groups. IMPA (angle of lower incisors and mandibular plane) decreased in groups with facemasks and increased in other groups. Conclusions Bone-anchored maxillary protraction can promote greater maxillary forward movement and correct the Class III intermaxillary relationship better, in addition to showing less clockwise rotation of mandible and labial proclination of upper incisors. However, strengthening anchorage could not inhibit mandibular growth better and the lingual inclination of lower incisors caused by the treatment is related to the use of a facemask.