BACKGROUND:Ilizarov bone transport is very effective in the treatment of open large tibial bone defects,but there are still complications,among which the difficulty of junction healing is one of the difficult points in treatment. OBJECTIVE:To investigate the effect of Ilizarov bone transport combined with antibiotic bone cement on junction healing after operation of open large tibial bone defect. METHODS:Totally 51 patients with open large tibial bone defect(bone defect>4 cm)admitted to Binzhou Medical University Hospital from August 2010 to January 2022 were selected,of which 28 received Ilizarov bone transport alone(control group)and 23 received Ilizarov bone transport combined with antibiotic bone cement treatment(trial group).External fixation time,bone healing time,bone healing index,visual analog scale score during bone removal,bone defect limb function,junction healing and complications at the final follow-up were statistically compared between the two groups. RESULTS AND CONCLUSION:(1)All the 51 patients were followed up for a mean of(22.53±5.77)months.External fixation time,bone healing time,bone healing index,postoperative infection rate,and non-healing rate of junction were less in the trial group than those in the control group(P<0.05).There was no significant difference between the two groups in visual analog scale scores at 6 months after the second surgery and in the functional excellence and good rate of limb with bone defect at the final follow-up(P>0.05).(2)These findings indicate that compared with the Ilizarov bone transport alone,Ilizarov bone transport combined with antibiotic bone cement treatment can promote the healing of open tibial fracture junction and increase the rate of bone healing.

Objective To study the relationship between serum insulin-like growth factor-1 (IGF-1) and resistin levels and osteoporosis in patients with type 2 diabetes mellitus (T2DM). Methods This study was conducted on 306 T2DM patients admitted to Baoding No.2 Central Hospital from January 2018 to January 2022. According to the detection results of bone mineral density, the patients were divided into osteoporosis group (T≤-2.5) and non-osteoporosis group (T>-2.5). The differences in IGF-1, resistin and bone mineral density were compared between the two groups. Pearson correlation analysis was used to analyze the correlation between serum IGF-1 and resistin levels and bone mineral density in patients with osteoporosis. Receiver operating characteristic (ROC) curve was applied to evaluate the application value of IGF-1 and resistin in predicting osteoporosis in patients with T2DM. Patients with T2DM complicated with osteoporosis were followed up for 2 years, and the occurrence of fractures was assessed. After univariate analysis, multivariate logistic regression analysis was applied to screen the risk factors for fractures in T2DM patients with osteoporosis. Results The incidence rate of osteoporosis in patients with T2DM was 53.59% (164/306). The IGF-1 level and bone mineral density level in the osteoporosis group were lower than those in the non-osteoporosis group, while the level of resistin was higher than that in the non-osteoporosis group (P<0.05). Serum IGF-1 in patients with osteoporosis was positively correlated with bone mineral density, and serum resistin was negatively correlated with bone mineral density (P<0.05). The AUC, sensitivity and specificity of combination of IGF-1 and resistin in predicting osteoporosis were 0.888, 82.93% and 62.68% respectively, which were all higher than those of single factor prediction (P<0.05). The 164 T2DM patients with osteoporosis were followed up for two years, and 15 patients developed fragility fractures, with the incidence of fracture of 9.15% (15/164). Multivariate analysis showed that hypoproteinemia, high-intensity exercise, lack of nutritional management, low IGF-1, and high resistin were risk factors for fractures in patients with T2DM complicated with osteoporosis (P<0.05). Conclusion For patients with T2DM, the incidence rates of osteoporosis and fractures are high. The levels of IGF-1 and resistin are closely related to bone mineral density, which can be combined to predict osteoporosis. Hypoproteinemia, high-intensity exercise, lack of nutritional management, low IGF-1 and high resistin are risk factors for fractures in T2DM patients with osteoporosis. It is necessary to carry out targeted preventive measures in clinical practice to reduce the incidence rate of fractures.

OBJECTIVE: To prepare decellularized nerve grafts from alpha-1, 3-galactosyltransferase (GGTA1) gene-edited pigs and explore their biocompatibility for xenotransplantation. METHODS: The sciatic nerves from wild-type pigs and GGTA1 gene-edited pigs were obtained and underwent decellularization. The alpha-galactosidase (α-gal) content in the sciatic nerves of GGTA1 gene-edited pigs was detected by using IB4 fluorescence staining and ELISA method to verify the knockout status of the GGTA1 gene, and using human sciatic nerve as a control. HE staining and scanning electron microscopy observation were used to observe the structure of the nerve samples. Immunofluorescence staining and DNA content determination were used to evaluate the degree of decellularization of the nerve samples. Fourteen nude mice were taken, and subcutaneous capsules were prepared on both sides of the spine. Decellularized nerve samples of wild-type pigs ( n=7) and GGTA1 gene-edited pigs ( n=7) were randomly implanted in the subcutaneous capsules. Blood was drawn at 1, 3, 5, and 7 days after implantation to detect neutrophil counting. RESULTS: IB4 fluorescence staining and ELISA detection showed that GGTA1 gene was successfully knocked out in the nerves of GGTA1 gene-edited pigs. HE staining showed that the structure of the decellularized nerve from GGTA1 gene-edited pigs was well preserved; the nerve basement membrane tube structure was visible under scanning electron microscopy; no cell nuclei was observed, and the extracellular matrix components was retained in the nerve grafts by immunofluorescence staining; and the DNA content was significantly reduced when compared with the normal nerves ( P<0.05). In vivo experiments showed that the number of neutrophils in the two groups were similar at 1, 3, and 7 days after implantation, with no significant difference ( P>0.05); only at 5 days, the number of neutrophils was significantly lower in the GGTA1 gene-edited pigs than in the wild-type pigs ( P<0.05). CONCLUSION The decellularized nerve grafts from GGTA1 gene-edited pigs have well-preserved nerve structure, complete decellularization, retain the natural nerve basement membrane tube structure and components, and low immune response after xenotransplantation through in vitro experiments.
Animals ; Transplantation, Heterologous ; Galactosyltransferases/genetics* ; Sciatic Nerve/immunology* ; Swine ; Tissue Engineering/methods* ; Humans ; Graft Rejection/prevention & control* ; Gene Editing ; Mice ; Mice, Nude ; Heterografts/immunology* ; Animals, Genetically Modified ; Tissue Scaffolds ; Decellularized Extracellular Matrix

From October 2021 to February 2023, we retrospectively analyzed the clinical and laboratory data of six patients (three male and three female, median age: 54 years, age range: 29-73 years) with mast cell leukemia (MCL) diagnosed in the First Affiliated Hospital of Soochow University (The Mastocytosis Collaborative Network of China). All patients had acute MCL, with at least one C-finding present. The main clinical presentations were hypoalbuminemia ( n=4), fatigue ( n=3), fever ( n=2), abdominal discomfort ( n=2), osteolytic lesions ( n=2), dizziness ( n=1), skin flushing ( n=1), and weight loss ( n=1). Splenomegaly and lymphadenopathy were noted in six and three patients, respectively. Six patients were strongly positive for CD117, five were positive for CD30 and CD25, and four were positive for CD2. Four patients had a normal karyotype and two patients had an abnormal karyotype. Gene mutations were detected in 4/6 cases. The median serum tryptase level was 24.9 (range: 20.1-171.9) μg/L. Two patients were treated with venetoclax and azacitidine for induction (one patient achieved partial remission by combination with afatinib, while there was no remission after combination with dasatinib in the other patient). Two patients did not achieve complete remission despite treatment with cladribine and imatinib, respectively. One patient treated with interferon combined with glucocorticoids was lost to follow-up, and one patient abandoned treatment. The follow-up time ranged from 1.1 to 21.7 months. Three patients died and two survived. Overall, MCL is a rare subtype of systemic mastocytosis with heterogeneous clinical course, and these patients have poor outcome. A better understanding of the clinical characteristics, treatment, and prognosis of MCL is urgently needed.

Objective:To discuss the effect of long-term use of chlorhexidine on the resistance of Enterococcus faecalis(E.faecalis),and to clarify its mechanism.Methods:The standard strain of E.faecalis was repeatedly exposed to chlorhexidine for 10 generations,and the minimum inhibitory concentration(MIC)was recorded at each passage.The bacteria collected from the 10th generation with increased MIC values were designated as the E.faecalis chlorhexidine-resistant strains(E.faecalis-Cs).The growth curves of two strains were drawn;the morphology of two strains were observed by transmission electron microscope;the number of biofilm formation of two strains was detected by crystal violet staining;the bacterial hydrophobicities of two strains were detected by microbial adhesion to hydrocarbons(MATH)method;the expression levels of S-ribosylhomocysteine lyase(LuxS)mRNA in the bacterial biofilms of two strains were detected by real-time fluorescence quantitative PCR(RT-qPCR)method.Results:From the 0th to the 10th generation,the MIC values of E.faecalis were gradually increased.The growth curves of E.faecalis and E.faecalis-Cs showed no significant differences.The transmission electron microscope observation results showed that both E.faecalis and E.faecalis-Cs appeared oval or diplococcal,with intact cell wall structures,smooth edges,and evenly distributed cytoplasm.There were no significant differences in the morphology,size,cell wall thickness,or integrity between two types of bacteria.The crystal violet staining results showed that compared with E.faecalis,the number of biofilm formation of E.faecalis-Cs was significantly increased(P<0.05).The MATH results showed tha the hydrophobicity of E.faecalis-Cs was significantly higher than that of E.faecalis(P<0.05).The RT-qPCR results showed that the expression level of LuxS mRNA in the biofilms of E.faecalis-Cs was significantly higher than that of E.faecalis(P<0.05).Conclusion:E.faecalis develops the resistance after repeated exposure to the chlorhexidine,and the pathogenicity of the resistant strain is enhanced.The high expressin of quorum sensing(QS)system LuxS gene and stronger biofilm forming ability of bacteria may be the potential mechanism for E.faecalis to tolerate the chlorhexidine.

Objective:To analyze the root canal diameter of the mandibular first premolar by using finite element analysis to simulate the stress distribution of dentin under three different preparation methods,and to provide the basis for clinical root canal preparation strategies of the mandibular first premolars.Methods:Twenty-one patients with complete cone beam computed tomography(CBCT)images were selected.The original DICOM format data from CBCT were imported into Mimics 21.0 software to measure the root canal diameter at 3,6,9,and 12 mm from the apex and the root canal taper was segmentally calculated.Based on this,three-dimensional finite element models of the dental and periodontal tissues were constructed.Control group,maximum diameter preparation group,uniform preparation group,and 0.06 taper instrument preparation group were designed.In ANSYS Workbench 17.0 finite element analysis software,a 200 N load was applied to the buccal,lingual,and occlusal surfaces in various groups,and the stresses on dentin in various groups were analyzed.Results:The analysis of root canal taper at 3-6 mm,6-9 mm,and 9-12 mm from the apex of mandibular first premolar teeth showed that the taper was similar in the mesial-distal direction at 3-6 mm from the apex.The average taper in the buccal-lingual direction at 6-9 mm from the apex was 0.29,which was greater than the taper in the apical 1/3 and coronal 1/3.Under the same load,the peak stress values in dentin of mandibular first premolar teech in various groups were increased sequentially:4.693 6,16.304 0,14.278 0,and 18.682 0 MPa.The stress in maximum diameter preparation group concentrated on the canal wall with the highest stress value.The stress in uniform preparation group concentrated on the root surface,and the stress values on each section were lower than those in maximum diameter preparation group.The stress in 0.06 taper instrument preparation group concentrated on the apical 1/3 of the root surface.Conclusion:The root canal of the mandibular first premolar has a unique elliptical taper shape,and there are significant differences in diameter and taper between the mesial-distal and buccal-lingual directions.Different preparation methods result in different stress distributions on the canal wall,and the uniform preparation is the best method for enlarging the canal.

Objective To evaluate the preservation effect of normothermic mechanical perfusion with red blood cells from humanized genetically modified pig on severed human limbs.Methods Severed human limbs were perfused with red blood cells from humanized genetically modified pigs for 6 h.Perfusion solution was taken every hour to measure the oxygen partial pressure,Na+,K+,Ca2+,pH value,glucose,lactic acid and creatine kinase levels.Superficial flexor muscle was sampled to detect the changes of tumor necrosis factor(TNF)-α,interleukin(IL)-2 and IL-1 levels.At 0 and 6 h after perfusion,the superficial flexor muscles of the forearm were taken for pathological examination.Intercellular space and glycogen consumption of skeletal muscles were observed.An appropriate amount of forearm vessels was collected every 2 h to detect the apoptosis of vascular endothelial cells.X-ray angiography was performed before perfusion and 6 h after perfusion to observe the filling degree of finger-tip peripheral vessels.Results The oxygen partial pressure was observed in the normal range throughout the perfusion.Na+concentration peaked at 1 h,reaching 138.7 mmol/L,and then fluctuated within the normal range.K+level peaked at 2 h up to 6.08 mmol/L,then decreased and fluctuated within the normal range.Ca2+concentration reached the peak at 4 h,up to 1.03 mmol/L.Glucose level was gradually decreased at the beginning of perfusion,reaching the lowest value of 17.7 mmol/L at 2 h after perfusion,and then maintained a dynamic balance.The pH value was decreased to 7.28 at 6 h after perfusion.The lactic acid level was increased to 9.6 mmol/L at 1 h after perfusion,and then gradually decreased.The creatine kinase level was increased at the start of perfusion,reached the peak at 2 h up to 20 030 U/L,then decreased and remained stable at the end of perfusion.At the end of perfusion,the morphology of muscle fibers was normal,the gap among muscle fibers was expanded slightly,and the glycogen of skeletal muscles was not significantly accumulated.At 0 h perfusion,the number of apoptotic cells in vascular endothelial cells was large,which was declined at 6 h perfusion.Evident vascular filling was observed at 0 h,and the filling degree of some finger-tip vessels was decreased at 6 h.Conclusions Normothermic mechanical perfusion of severed human limbs with red blood cells from humanized genetically modified pigs may continuously and stably supply energy and oxygen,adjust the ion pH balance of perfusion solution,maintain normal cellular metabolism and exerts certain protective effect upon severed human limbs.

Limb dismemberment injuries are common in clinical practice,and safe and effective protection of the dismembered limb is the key to successful limb replantation.Normothermic machine perfusion has made significant breakthrough in the field of organ transplantation,which may maintain the active function of organs and tissues for a long period of time and prolong the preservation time.These findings have been validated in large animal models and clinical trials.Meantime,this technology is expected to provide novel reference for the preservation and functional recovery of severed limbs.Therefore,this paper reviews the problems of static cold preservation in the preservation of disarticulated limbs,the development history of mechanical perfusion,the current status of clinical application of ambient mechanical perfusion of disarticulated limbs as well as the problems to be solved,and looks forward to the direction of its development and the prospect of its clinical application,with a view to promoting the wide application of this technology in the clinic.

Although blood banks based on human blood can provide blood transfusions for the wounded timely and effec-tively,scientific research has never given up on finding new blood sources due to the restrictions of human blood sources.With the application of transgenic technology and the successful breeding of gene-edited pigs,gene-edited pig blood as a po-tential source of clinical transfusion has attracted wide attention.Now there are preclinical studies showing the feasibility of transfusing gene-edited pig red blood cells into primates.This paper discusses the related research and future development of xenogeneic transfusion of porcine red blood cells by gene editing.

Objective To investigate the differences and the immunocompatibility of wild-type (WT), four-gene modified (TKO/hCD55) and six-gene modified (TKO/hCD55/hCD46/hTBM) pig erythrocytes with human serum. Methods The blood samples were collected from 20 volunteers with different blood groups. WT, TKO/hCD55, TKO/hCD55/hCD46/hTBM pig erythrocytes, ABO-compatible (ABO-C) and ABO-incompatible (ABO-I) human erythrocytes were exposed to human serum of different blood groups, respectively. The blood agglutination and antigen-antibody binding levels (IgG, IgM) and complement-dependent cytotoxicity were detected. The immunocompatibility of two types of genetically modified pig erythrocytes with human serum was evaluated. Results No significant blood agglutination was observed in the ABO-C group. The blood agglutination levels in the WT and ABO-I groups were higher than those in the TKO/hCD55 and TKO/hCD55/hCD46/hTBM groups (all P<0.001). The level of erythrocyte lysis in the WT group was higher than those in the ABO-C, TKO/hCD55 and TKO/hCD55/hCD46/hTBM groups. The level of erythrocyte lysis in the ABO-I group was higher than those in the TKO/hCD55 and TKO/hCD55/hCD46/hTBM groups (both P<0.01). The pig erythrocyte binding level with IgM and IgG in the TKO/hCD55 group was lower than those in the WT and ABO-I groups. The pig erythrocyte binding level with IgG and IgM in the TKO/hCD55/hCD46/hTBM group was lower than that in the WT group and pig erythrocyte binding level with IgG was lower than that in the ABO-I group (all P<0.05). Conclusions The immunocompatibility of genetically modified pig erythrocytes is better than that of wild-type pigs and close to that of ABO-C pigs. Humanized pig erythrocytes may be considered as a blood source when blood sources are extremely scarce.