Objective To evaluate the histocompatibil ity of porous hydroxyapatite (HAP) coating NiTi shape memory alloy and to provide a theoretical basis for its cl inical appl ication in bone defect repair. Methods Twenty-four Chinchilla rabbits weighing 2.0-2.5 kg were randomized into experimental group and control group (n=12). HAP coating NiTi shape memory alloy was implanted into the distal part of left femur of 12 rabbits in the experimental group, while holes without alloy implantation were performed on the control group. At 7, 14, 28 and 56 days after implantation, the animals werekilled (3 rabbits in each group at a time). Gross observation, histology observation, BMP-2 immunohistochemistry observation and image grey scale analysis were performed. And the histology observation was evaluated by GB/T16886.6-1997 in terms of inflammation, capsule wall of fibrous tissue, materials degradation and the response of peripheral tissue. Results All of the animals survived until being killed. The implants reached a peak embedded in bone tissue wholly, without loosening and bone absorption. The inflammatory cell infiltration and fibrous hyperplasia were at 7 days after implantation, with the formation of cyst wall of fibrous tissue and the implant wrapped by the cyst wall. The response of connective tissue proliferation was still obvious in partial samples of experimental group at 56 days after implantation, which was wrose than the control group but consistent with the in vivo implantation standard of GB/T16886.6-1997. Immunohistochemistry observation displayed the endogenous BMP-2 were in the cytoplasm of MSCs and osteoblast. The result of image analysis showed the expression of BMP-2 were staged in line with the repair of bone defect, two groups witnessed the peak expression of the BMP-2 at 14 days after implantation. There wereno significant differences among different time points in the staining gray scale of BMP-2 (P gt; 0.05). Conclusion HAP coating NiTi shape memory alloy, as a biomedical material, has excellent histocompatibility with bone.
【Abstract】 Objective To evaluate the effectiveness of HA mixed with adenovirus mediated rhBMP-2 gene (AdvrhBMP-2) transferred BMSCs of goats on distraction osteogenesis. Methods Nineteen adult goats were used for the experiment,no matter they were male or female, and the weight of the goats were 15-20 kg. The 10 mL marrow was obtained from theil iac crest of each goat. The BMSCs was expanded and passaged conventionally. The 3th BMSCs was infected by Adv-rhBMP-2 at 200 multipl icity of infection (MOI). The 1×108 infected BMSCs were digested by 0.25% trypsin and collected, then mixed with HA. The right tibia lengthening models were developed, and mixture with BMSCs was injected in the osteotomy position. The goats were divided randomly into 4 groups according to the material injected in operation, group A: Adv-rhBMP-2/BMSCs/HA (n=6); group B: Adv-rhBMP-2/BMSCs (n=5); group C: Adv-β-gal/BMSCs/HA (n=4); group D: sham without any injections (n=4). After a seven-day latency period following ostectomy, distraction was carried out at a rate of 1 mm/day for 4 weeks. Roentgenography was practiced in 5, 8 and 12 weeks. After 12 weeks, the goats were sacrificed and dual-energy X-ray absorptiometry (DXA), biomechanical test and histology results were studied. Results After five and eight weeks surgery, X-raytest showed the distraction callus was more in group A and B than group C and D, and the radiographic score was significantly higher in group A and B than in the other two groups(P lt; 0.05); after 12 weeks surgery, the continued callus was formed in the distraction defects in all groups. DXA showed the mean bone mineral content of distraction callus in group A, B, C, D was (4.175 ± 1.921), (2.600 ± 0.638), (2.425 ± 0.826) and (1.175 ± 0.574) g, and the mean bone mineral density was (0.612 ± 0.196), (0.630 ± 0.159), (0.450 ± 0.166) and (0.266 ± 0.113) g/cm2. The group A and B was significantly higher than group C and D (P lt; 0.05).Biomechanical test showed the maximum loading of group A, B, C, D was (490.20 ± 155.08), (350.59 ± 80.48), (221.95 ± 68.79) and (150.65 ± 92.29) N, and elastic modulus was (178.24 ± 105.80), (105.88 ± 27.09), (81.18 ± 48.67) and (50.35 ± 47.64) MPa. The group A was significantly higher than in group C and D (P lt; 0.05). Histology observation revealed abundant bone formation in the distraction defects in group A, and the bone trabecula was arranged longitudinal and netl ike. Histomorphology analysis revealed the bone volume in group A, B, C, D was 72.35% ± 5.68%, 67.58% ± 7.42%, 49.63% ± 4.87% and 38.87% ± 2.35%, and the bone formation was significantly greater in group A compared with group D (P lt; 0.05). Conclusion HA mixed with rhBMP-2 modified BMSCs can accelerate distraction osteogenesis in goats.
Objective To study repair of osteochondral defects by using composite of autologous BMSCs and chitosan/HAP (CS/HAP) bilayered scaffold in rabbits and its feasibil ity as osteochondral tissue engineering scaffolds. Methods CS/HAP bilayered scaffolds were produced with CS and HAP using a lyophil ization and sintering method. The pore size of the scaffold was observed by scanning electron microscopy (SEM). Anhydrous ethanol substitution method determined its porosity. BMSCs were isolated from bone marrow and cultured by general bone marrow methods. Both CD44 and CD45 on the BMSCs surface were detected with immunocytochemistry to identify BMSCs. Cell-scaffold complex was made with BMSCs as seed cells and CS/HAP bilayered scaffold as carrier by fibrin glue planting technique. The distribution ofBMSCs in CS/HAP scaffold was tested by SEM. The osteochondral defect (4 mm in diameter and 3 mm in height) model was made in the right knee joint of 36 Japanese white rabbits, which were randomly divided into 3 groups. Defects were repaired with CS/HAP and BMSCs composite ( group A, n=12) and with CS/HAP implants (group B, n=12); defects were not treated as a control (group C, n=12). Histological evaluation and gross observation were carried out at 6 weeks (n=6 in each group) and 12 weeks (n=6 in each group) postoperatively. Semi-quantitative histomorphological analysis was done to evaluate the repair cartilage tissue according to the modified Wakitani grading scale. Results CS/HAP bilayered scaffold possessed a porosity of 76.00% ± 5.01% and pore size of 200-400 μm (mean 300 μm ) in CS layer, and 72.00% ± 4.23% and 200-500 μm (mean 350 μm) in HAP layer, respectively. BMSCs formed colonies within 10-14 days. Immunocytochemistry results showed BMSCs had positive CD44 expression and negative CD45 expression. At 6 and 12 weeks after operation, gross and histological observation showed that the cartilage defects were fully filled with regenerated tissue, but bone defects were partially repaired in group A; the cartilage and bone defects were partially filled with regenerated tissue in group B and group C. The modified Wakitani grading scale were 5.17 ± 1.17 and 3.20 ± 0.75 in group A, 9.00 ± 0.63 and 6.00 ± 0.89 in group B, and 10.00 ± 0.89 and 9.60 ± 0.82 in group C at 6 weeks and 12 weeks postoperatively, respectively; showing significant differences between group A and groups B, C (P lt; 0.05). Conclusion The novel CS/HAP bilayered scaffold possesses porous structure and will possibly become a newbiomaterial of osteochondral tissue engineering.
ObjectiveTo evaluate the use of machine learning algorithms for the prediction and characterization of cardiac thrombosis in patients with valvular heart disease and atrial fibrillation. MethodsThis article collected data of patients with valvular disease and atrial fibrillation from West China Hospital of Sichuan University and its branches from 2016 to 2021. From a total of 2 515 patients who underwent valve surgery, 886 patients with valvular disease and atrial fibrillation were included in the study, including 545 (61.5%) males and 341 (38.5%) females, with a mean age of 55.62±9.26 years, and 192 patients had intraoperatively confirmed cardiac thrombosis. We used five supervised machine learning algorithms to predict thrombosis in patients. Based on the clinical data of the patients (33 features after feature screening), the 10-fold nested cross-validation method was used to evaluate the predictive effect of the model through evaluation indicators such as area under the curve, F1 score and Matthews correlation coefficient. Finally, the SHAP interpretation method was used to interpret the model, and the characteristics of the model were analyzed using a patient as an example. ResultsThe final experiment showed that the random forest classifier had the best comprehensive evaluation indicators, the area under the receiver operating characteristic curve was 0.748±0.043, and the accuracy rate reached 79.2%. Interpretation and analysis of the model showed that factors such as stroke volume, peak mitral E-wave velocity and tricuspid pressure gradient were important factors influencing the prediction. ConclusionThe random forest model achieves the best predictive performance and is expected to be used by clinicians as an aided decision-making tool for screening high-embolic risk patients with valvular atrial fibrillation.
Objective To develop a machine learning (ML) model to predict the risk of death in intensive care unit (ICU) patients with chronic obstructive pulmonary disease (COPD), explain the factors related to the risk of death in COPD patients, and solve the "black box" problem of ML model. Methods A total of 8088 patients with severe COPD were selected from the eICU Collaborative Research Database (eICU-CRD). Data within the initial 24 hours of each ICU stay were extracted and randomly divided, with 70% for model training and 30% for model validation. The LASSO regression was deployed for predictor variable selection to avoid overfitting. Five ML models were employed to predict in-hospital mortality. The prediction performance of the ML models was compared with alternative models using the area under curve (AUC), while SHAP (SHapley Additive exPlanations) method was used to explain this random forest (RF) model. Results The RF model performed best among the APACHE IVa scoring system and five ML models with the AUC of 0.830 (95%CI 0.806 - 0.855). The SHAP method detects the top 10 predictors according to the importance ranking and the minimum of non-invasive systolic blood pressure was recognized as the most significant predictor variable. Conclusion Leveraging ML model to capture risk factors and using the SHAP method to interpret the prediction outcome can predict the risk of death of patients early, which helps clinicians make accurate treatment plans and allocate medical resources rationally.
Objective To systematically review the effectiveness of letrozole combined with GnRH antagonist for in vitro fertilization-embryo transfer (IVF-ET) in poor responders. Methods Such databases as VIP, CNKI, PubMed, EMbase and FMJS were electronically searched for randomized controlled trials (RCTs) or quasi-RCTs on the effectiveness of letrozole combined with GnRH antagonist for IVF-ET. Two reviewers independently screened literature according to the inclusion and exclusion criteria, extracted data, and assessed methodological quality. Then, meta-analysis was performed using RevMan 5.0 software. Results Six studies involving 977 patients were finally included. The results of meta-analysis showed that, for IVF-ET poor responders, compared with the control group, the letrozole combined with GnRH antagonist group had less dosage of Gn (MD=–8.05, 95%CI –13.67 to –2.43, P=0.005), and lower serum E2 value on the day of HCG administration (MD= –1 026.41, 95%CI –1 949.61 to –103.20, P=0.03). However, no significant difference was found in the number of ocytes obtained (MD= –0.61, 95%CI –2.41 to –1.19, P=0.51) and clinical pregnancy rates (OR=1.03, 95%CI 0.53 to 2.02, P=0.92) between the two groups. Conclusion As for the effectiveness of impelling-ovulation treatment for IVF-ET in poor responders, letrozole combined with GnRH antagonist is similar to the control scheme in clinical outcomes, but it reduces the dosage of Gn and treatment costs of IVF-ET, which provides another clinical option for poor responders. Due to the limited quantity and quality of the included studies as well as the difference in methodology, we suggest this above conclusion could be taken as a reference for clinical analysis which needs to be further evaluated in its effects.
Objective To prepare carboxymethyl-chitosan/hyaluronic acid/poly(vinyl alcohol) (CHP) blend membrane, evaluate its physicochemical properties and intraocular biocompatibil ity and to investigate its feasibil ity to be appl ied to glaucoma filtering surgery. Methods CHP blend membrane was prepared using solution casting method after blending carboxymethyl-chitosan, HA and poly(vinyl alcohol) in a proportion of 5 ∶ 4 ∶ 1 (M/M). Its water absorption rate, swell ing rate, permeabil ity, and mechanical properties were detected. Subconjunctival fibroblasts separated from subconjuncitival tissue of New Zealand white rabbits were cultured, and the cells at passage 4 were cultured on cell culture plate with or without the CHP blend membrane, serving as the experimental group and the control group, respectively. Effectof the CHP blend membrane on the subconjunctival fibroblasts was tested by MTT method 24, 48, and 72 hours after culture. Six New Zealand white rabbits were randomly divided into two groups (n=3 rabbits per group), and the CHP blend membrane and SK gel were implanted into the rabbits’ subconjunctival space and anterior chamber in the experimental group and the control group, respectively. Sl it lamp observation and binocular reaction record were conducted 1, 3, 5, 9, 11, 20, 30, 45, and 60 days after operation. Corneal tissue harvested from the experimental group was observed using scanning electron microscope 15 days after operation to study ophthalmic biocompatibil ity and biodegradabil ity. Results The water absorption rate and the swell ing rate of the CHP blend membrane was 83.8% ± 1.3% and 3.59 ± 0.50, respectively. The tensile strength of the dry and the wet CHP blend membrane was (20.59 ± 1.73) and (0.51 ± 0.13) MPa, respectively. The breaking elongation rate of the dry and the wet CHP blend membcane was 10.69% ± 1.16% and 53.15% ± 2.46%, respectively. The CHP blend membrane had good permeabil ity to NaCl and L-tyrosine. Absorbance (A) value of the experimental group 24, 48, and 72 hours after breeding was 0.207 ± 0.083, 0.174 ± 0.080, and 0.181 ± 0.048, respectively, while the A value of the control group was 0.284 ± 0.011, 0.272 ± 0.083, and 0.307 ± 0.056, respectively. Significant difference was evident between two groups (P lt; 0.05). In the experimental group, a small amount of floccus was exuded around the implanted membrane 1 day after operation; the floccus was absorbed on the third day, and there was no obvious inflammatory reaction occurring on the eleventh day. Most of the membrane degraded on the sixtieth day. Scanning electron microscope observation showed that the hexagonal morphology of the corneal endothel ial cells was intact, and no degradation particles adhered to the surface. In the control group, the implantation of SK gel into anterior chamber was unsuccessful because the SK gel was quite soft and easily broken. In the experimental group, mild hyperemia emerged around the implanted membrane 1 day after the subconjunctival implantation of the membrane, and it became normal on the ninth day. No corneal edema and inflammatory reaction of anterior chamber occurred till the sixtieth day. The results in the control group and the experiment group were similar. Conclusion Due to its good physicochemical properties and biocompatibil ity, the CHP blend membrane has potential appl ications in glaucomafiltering surgery.
Abstract A new type of artificial material could possibly be produced by combination of osteoblast with bioactive material in culture, and thus, make the material "alive" . To study the behavior of osteoblast cultured with bioactive materials, the osteoblasts were isolated from the periosteum of Newzeland Rabbits tibia, and cultured in RPMI1640 medium. After 13 subcultures, the cells were identified as osteoblast in vitro by electron microscope, AKP activity and detection of mineral deposition ability. The osteoblasts were subcultured with three bioactive materials: bioactive glass ceramics (BGC), hydroxyapatite (HA), and double phase hydroxyapatite (HA/TCP). After incubationfor 48 hours, scan electron microscope, 3H-TDR, XRD, RS and EDXAwere performed. The results showed that the osteoblasts grew on the HA/TCR had a higher proliferation rate and better osteoblastoid shape than those grew on BCG and HA. Themechanism of the growth of osteoblasts on bioactive materials was discussed, and the factors influencing the growth of osteoblast were analyzed.
目的:探讨老年人自发性气胸的临床特点、治疗及预后。方法:对本院在2005年11月至2008年4月间收治的79例老年人自发性气胸患者临床资料进行回顾性分析。结果:老年人自发性气胸大多有肺部基础疾病,临床表现缺乏特异性,本组误诊为慢性阻塞性肺病急性发作4例、左心衰2例、支气管哮喘1例。气胸类型: 张力性气胸47例(72.1%),闭合性气胸11例,交通性气胸21例。采用以肋间闭式引流的为主的治疗措施,效果好。结论:老年人自发性气胸大多有肺部基础疾病, 易误诊,气胸的类型以张力性气胸多见,治疗多需排气减压术,及早的排气减压可望缓解症状,缩短肺复张时间,减少患者住院天数, 降低死亡率,提高老年人生活质量。
In order to investigate immune protection against swine-origin influenza virus (S-OIV) A H1N1, the helper-dependent adenovirus vector (HDAd) system was exploited to construct recombinant HDAd encoding hemagglutinin (HA). The HA gene was synthesized and cloned to the HDAd backbone. Then, the HDAd/HA DNA molecules were transfected into 293Cre4 cells with calcium phosphate. The cells were infected by helper virus 16 hours after the transfection. The 293Cre4 cells were coinfected with HDAd/HA and the helper virus for large-scale preparation of HDAd/HA. The HDAd/HA was obtained and purified twice with CsCl density ultracentrifugation and observed morphologically under transmission electron microscope, and the expression of HA protein was analyzed with RT-PCR. Recombinant HDAd/HA expressing HA protein was successfully constructed which could pave the way for in vivo investigation on immunogenicity and efficacy against S-OIV A H1N1 infection.