BACKGROUND:In recent years,with the development of biological scaffold materials and bioprinting technology,tissue-engineered bone has become a research hotspot in bone defect repair. OBJECTIVE:To summarize the current treatment methods for bone defects,summarize the biomaterials and bioprinting technology for preparing tissue-engineered bone scaffolds,and explore the application of biomaterials and printing technology in tissue engineering and the current challenges. METHODS:Search terms were"bone defect,tissue engineering,biomaterials,3D printing technology,4D printing technology,bioprinting,biological scaffold,bone repair"in Chinese and English.Relevant documents published from January 1,2009 to December 1,2022 were retrieved on CNKI,PubMed and Web of Science databases.After being screened by the first author,high-quality references were added.A total of 93 articles were included for review. RESULTS AND CONCLUSION:The main treatment methods for bone defects include bone transplantation,membrane-guided regeneration,gene therapy,bone tissue engineering,etc.The best treatment method is still uncertain.Bone tissue engineering technology is a new technology for the treatment of bone defects.It has become the focus of current research by constructing three-dimensional structures that can promote the proliferation and differentiation of osteoblasts and enhance the ability of bone formation.Biological scaffold materials are diverse,with their characteristics,advantages and disadvantages.A single biological material cannot meet the demand for tissue-engineered bone for the scaffold.Usually,multiple materials are combined to complement each other,which is to meet the demand for mechanical properties while taking into account the biological properties of the scaffold.Bioprinting technology can adjust the pore of the scaffold,build a complex spatial structure,and is more conducive to cell adhesion,proliferation and differentiation.The emerging 4D printing technology introduces"time"as the fourth dimension to make the prepared scaffold dynamic.With the synchronous development of smart materials,4D printing technology provides the possibility of efficient repair of bone defects in the future.

Objective:To analyze the epidemiological characteristics of norovirus (NoV) acute gastroenteritis (AGE) outbreaks caused by GII.17[P17] variant in China, 2022.Methods:Information and specimens of AGE outbreaks between January and December 2022 were collected. NoV RNA was detected in all specimens by real-time RT-PCR. The viral genome of the positive specimens were amplified, sequenced and analyzed.Results:Between January and December 2022, 360 AGE outbreaks were reported cumulatively, of which 266 outbreaks successfully obtained genotype results. GII.17 [P17] was one of the main genotypes and detected in 34 outbreaks (12.78%, 34/266), with the highest number of outbreaks detected in spring (6 outbreaks in March and 7 outbreaks in May), mainly in childcare facilities and primary schools (61.76%, 21/34). According to the result of NoV genotype analysis in different age groups, 14 strains of GII.17 [P17] in this study belonged to Cluster III b and SC III branch of Cluster III (Kawasaki308) in the capsid region and polymerase region, respectively, and both belonged to the same cluster as the variant strain (GZ41621 strain) that caused the NoV AGE outbreaks in China during the 2014/15 season. Compared to reference strains of Cluster I, Cluster II and Cluster III a, Cluster III b was provided with 22 amino acid mutations in VP1. The main amino acid changes in the subgroup of Cluster III b including the virus strains isolated in this study were at T294I and Q299R of antigen epitope A, an insertion mutation occurred at antigen epitope D, H353Q at the site I of the human histo-blood group antigen receptor binding site. The selection pressure analysis detected a large number of negative selection sites, indicating that negative selection plays an important role in the evolution of VP1 genes.Conclusions:GII.17 [P17] was one of the primary genotypes responsible for NoV diarrhea outbreaks in China in 2022. Phylogenetic analysis had revealed that it still belonged to the same cluster as the novel GII.17 [P17] variant (strain GZ41621) that caused NoV epidemics in China during the 2014/15 season, exhibiting minor amino acid variations at the potential epitope.

Objective:A recombinant adenoviral vector vaccine based on non-replicating human adenovirus type 5 (Ad5), encoding the conserved domain of respiratory syncytial virus G protein (RSV-G) was constructed. The immunogenicity and protective efficacy of this vaccine were subsequently evaluated in mice.Methods:The recombinant Ad5 vector plasmid (Ad5-Gbcc-Gacc) was constructed by inserted conserved domains of RSV A and RSV B. The recombinant adenovirus Ad5-Gbcc-Gacc was rescued in HEK293A cells. The genome of virus Ad5-Gbcc-Gacc was identified by multi-enzyme digestion, and the expression of Ad5-Gbcc-Gacc was verified by Western blot. Recombinant adenovirus was used to immunize BALB/c mice via intramuscular injection with signal dose, and then challenged with RSV Long strain at week 6. The levels of G specific IgG and antibody subtypes in serum were detected by enzyme-linked immunosorbent assay, the level of neutralizing antibodies was determined by micro-neutralization assay. After challenge, the mice′s weight was recorded daily, the copies of RSV virus in the lung and nasal tissues were detected. Pathological changes in lung tissue were also examined.Results:Western blot and multi-enzyme digestion identification confirmed the successful rescue of the recombinant adenovirus. Ad5-Gbcc-Gacc elicit high titers of specific IgG, robust neutralizing antibodies, and a balanced Th1/Th2 immune response in mice. In comparison to unimmunized controls, mice immunized with Ad5-Gbcc-Gacc reduced the viral copies in both lung and nasal tissue, and exhibited only minimal pathological damage of lung tissue following RSV challenge. In conclusion, Ad5-Gbcc-Gacc induced robust immunogenicity and offers protective effects against RSV infection in murine models.Conclusions:Ad5-Gbcc-Gacc induce robust immunogenicity and can protect mice from RSV challenge, which lays a foundation for further development of RSV vaccine based on G protein.

Objective:To construct and validate a risk prediction model for major complications 30 days after surgery in the elderly patients with hip fracture.Methods:A retrospective study was conducted to analyze the clinical data of 276 elderly patients with hip fracture who had been admitted to Department of Trauma and Orthopaedics, The Hospital Affiliated to Chengde Medical University from June 2019 to December 2021. There were 96 males and 180 females with an age of (74.5±9.3) years, and 139 femoral neck fractures and 137 intertrochanteric fractures. The outcome of this study was whether major complications occurred within 30 days after surgery. Multiple logistic regression analysis identified the risk factors for major complications in the elderly patients with hip fracture within 30 days after surgery. The forward step-by-step method and likelihood ratio test were used to screen the best prediction model. A nomogram was constructed to display the model. The stability and effectiveness of the model were evaluated by the receiver operating characteristic curve (ROC), Hosmer-Lemeshow goodness-of-fit test, clinical decision curve and clinical impact curve analysis.Results:Logistic regression analysis showed that decreased preoperative hemoglobin ( P< 0.05), time from admission to surgery >72 hours ( OR=3.001, 95% CI: 1.564 to 5.758, P<0.001), control of nutritional status (CONUT) score >4 points ( OR=3.394, 95% CI: 1.724 to 6.680, P<0.001), and age-adjusted modified frailty index (aamFI) >2 points ( OR=2.875, 95% CI: 1.548 to 5.339, P= 0.001), increased operation time ( OR=1.016, 95% CI: 1.006 to 1.025, P=0.001), and surgical bleeding >60 mL ( OR=2.373, 95% CI: 1.016 to 5.540, P=0.046) were independent risk factors for major complications within 30 days after surgery in the elderly patients with hip fracture. The area under the ROC curve in the logistic risk prediction model was 0.846 (95% CI: 0.799 to 0.889), and the results of Hosmer-Lemeshow goodness-of-fit test showed ( χ2=8.080, P=0.426). The clinical decision curve and clinical impact curve showed that the prediction model was accurate and effective. Conclusion:Based on the patients' preoperative hemoglobin, time from admission to surgery, control of nutritional status score, age-adjusted modified frailty index, operation time and surgical blood loss, this study has constructed successfully a risk prediction model for complications 30 days after surgery in the elderly patients with hip fracture which enables medical staff to predict the occurrence of major postoperative complications.

Objective:To express prokaryotically GII.4 human norovirus (HuNoV) VP2 protein and to prepare polyclonal antibody against VP2.Methods:Design specific primers to amplify the VP2 gene of GII.4 HuNoV, digest and connect to the prokaryotic expression vector pGEX-6P-1, transform the correctly identified recombinant plasmid into BL21 ( DE3) competent cells.Pick out and shake the monoclonal bacteria, and add IPTG to induce recombinant GST-VP2. The fusion protein was expressed, purified by GST affinity chromatography and digested to obtain GII.4 HuNoV VP2 protein. The relative molecular mass (Mr.×10 3) of the purified HuNoV VP2 protein was analyzed by SDS-PAGE. BALB/c mice were immunized with purified GII.4 HuNoV VP2 protein (0.5 mg/ml) to prepare polyclonal antibodies. Results:The VP2 protein of GII.4 HuNoV was successfully expressed and purified, with a relative molecular mass (Mr.×10 3) of about 29; the VP2 polyclonal antibody of GII.4 HuNoV was successfully prepared and its titer was as high as 1∶1 280 000. Western blot and indirect ELISA analysis showed that the polyclonal antibody could specifically bind to the VP2 antigen of GII.4 HuNoV. Conclusions:The purified GII.4 HuNoV VP2 after prokaryotic fusion expression can be used to prepare high titer polyclonal antibody.

Objective:To investigate the correlation between vitamin D deficiency and the severity of symptoms in children with vasovagal syncope (VVS).Methods:A prospective study was conducted. One hundred and twenty-two children diagnosed with VVS by head up tilt test in Department of Pediatric Cardiology and 130 healthy children without symptoms who underwent physical examination in the outpatient department of Child Healthcare Department of Second Hospital of Lanzhou University from December 2019 to May 2021 were selected and assigned to VVS group and control group, respectively. According to the diagnostic criteria of vitamin D deficiency, children in the VVS group were assigned to three subgroups: non-vitamin D deficiency, vitamin D deficiency, and severe vitamin D deficiency. All children underwent detailed history taking, physical examination, and level determination of serum 25 (OH) D. Children in the VVS group were scored for orthostatic intolerance (OI) symptoms including 10 symptoms: syncope, dizziness, nausea, palpitation, headache, tremor, chest tightness, blurred vision, profuse perspiration, and attention deficit. The differences in the age, gender, body mass index, blood pressure, and serum 25 (OH) D levels between VVS group and control group, and the differences regarding the age, gender, body mass index, blood pressure, serum 25 (OH) D levels and symptom scores among the three VVS subgroups were compared. Comparisons were performed using independent sample t test, ANOVA analysis, Chi square test and rank sum test. Pearson correlation analysis was used to analyze the correlation between serum 25 (OH) D levels and OI symptom scores in children with VVS. Results:The serum 25 (OH) D levels were significantly lower in the VVS group than those in the control group ((31±11) vs. (46±10) nmol/L, t=10.89, P<0.001). Vitamin D deficiency was more frequent in the VVS group (73.0% (89/122) vs. 24.6% (32/130), χ2=58.91, P<0.001). There were significant differences among the severe vitamin D deficiency subgroup, vitamin D deficiency subgroup, and non-vitamin D deficiency subgroup regarding the serum 25 (OH) D levels ((9.8±0.4) vs. (26.6±6.5) vs. (45.8±5.9) nmol/L, F=142.77, P<0.001) and the OI symptom scores ((14±1) vs. (10±2) vs. (7±2) scores, F=44.97, P<0.001). The scores of syncope, nausea, profuse perspiration, blurred vision and dizziness among the severe vitamin D deficiency subgroup, vitamin D deficiency subgroup, and non-vitamin D deficiency subgroup were statistically significant ( H=9.01, 7.52, 12.11, 7.07 and 9.54, respectively, all P<0.05). Pearson correlation analysis showed that the serum 25 (OH) D levels were negatively correlated with OI symptom scores in children with VVS ( r=-0.769, P<0.001). Conclusions:VVS children have significant vitamin D deficiency. The severity of symptoms increases with decreasing of vitamin D level. Syncope, nausea, and profuse perspiration are more likely to occur in children with severe vitamin D deficiency, and dizziness and blurred vision are more likely to occur in children with vitamin D deficiency.

Objective:To clarify the evolutionary characteristics and key site variations of the GII.6[P7] genome of norovirus disease outbreak in China.Methods:Genome amplification and sequencing of 46 GII.6[P7] positive samples monitored from CaliciNet China from 2018 to 2021. Simultaneous integration of all ORF1 (GII. P7) and ORF2 (GII.6) sequences for Bayesian evolutionary analysis. And the use of Simplot for restructuring analysis.Results:According to Bayesian evolution analysis, GII. P7 polymerase has temporal evolutionary characteristics, with an average base replacement rate of 2.067× 10 -3 nucleotide substitution/site/year, and recombination with 4 different VP1 genotypes (GII.6, GII.7, GII.14, GII.20). In the capsid region, GII.6 noroviruses can be further divided into GII.6a, GII.6b and GII.6c subtypes. The 46 strains in this study belong to the GII.6a subtype, which are divided into the same cluster as the virus strain NHBGR59 circulating in China in 2015. Simplot analysis determined that the recombination site of the GII.6[P7] strain in this study was at the ORF1-2 junction. The amino acid site variation of VP1 mainly occurred at the end of P1.1 and the P2 region. Compared with the reference strain of GII.6a subtype, there was no variation in the receptor binding site. Conclusions:The GII.6[P7] recombinant strains of the norovirus outbreak from 2018 to 2021 in China all belong to the GII.6a[P7] subtype.

Objective:To explore the expression of miR-216a in patients with acute pancreatitis (AP) associated with acute lung injury (ALI) and its influence on endothelial cells permeability.Methods:40 AP patients admitted in Department of Gastroenterology of the First Affiliated Hospital of Navy Medical University from December 2015 to March 2016 were collected and were classified into AP with ALI (AP-ALI group, n=13) and AP without ALI (AP group, n=27) according to the presence or absence of ALI. 8 normal volunteers were enrolled in the control group. Blood samples were collected and the plasma samples were separated. Plasma RNA was extracted. miR-216a level in plasma was detected by RT-PCR. Plasma exosomes were extracted by exosome extraction kit and identified by the electron microscopy. Exosome RNA was extracted. miR-216a level in exosome was detected by RT-PCR. Plasma exosomes of AP-ALI patients were co-cultured with human umbilical vein endothelial cells (HUVEC, AP-ALI-HUVEC group) and anti-miR-216a transfected HUVECs (AP-ALI-anti-miR-216a HUVEC group) for 24 hours, respectively, and untreated HUVECs served as control group. Trans-endothelium electrical resistance (TEER) was measured by Millicell Ers-2 epithelial volt-ohmmeter to evaluate the cell permeability. Results:RT-PCR results showed that the expression level of plasma miR-216a in AP-ALI group (14.45±1.64) was significantly higher than that in AP group (11.08±1.6) and the control group (5.37±1.54) ( P<0.01). Under electron microscope, plasma exosomes were goblet like vacuoles, with the size of about 50-90 nm. The plasma exosomal miR-216a level in the AP-ALI group (14.03±1.58) was significantly higher than that in the AP group (10.86±1.31) and the control group (5.01±0.79), and the difference was statistically significant ( P<0.01). The resistance value of HUVEC in the control group was referred as 1, and the resistance ratio of HUVEC in AP-ALI-HUVEC group was 0.74±0.04, which was significantly lower than that of HUVEC in AP-ALI-anti-miR-216a HUVEC group (1.02±0.08), the difference was statistically significant ( P<0.01). Conclusions:miR-216a was highly expressed in plasma exosomes of AP patients with ALI. miR-216a can increase endothelial cell permeability, which may be associated with ALI during AP.

As indications of radiotherapy in the treatment of breast cancer continue to expand, more and more patients need radiotherapy after mastectomy. With the development of breast reconstruction, radiotherapy and its timing will affect breast reconstruction while patients benefit from tumor treatment and may lead to different postoperative complications and cosmetic effects. How to optimize the comprehensive therapeutic strategies of postoperative breast reconstruction and radiotherapy for breast cancer, especially the techniques of breast reconstruction and the choices of radiotherapy timing, has become an issue of common concerns of multidisciplinary treatment involving radiotherapy, breast surgery, and plastic surgery. This paper aims to review and summarize the latest high-quality research in this field including the impact of radiotherapy and its timing on tissue expander/prosthetic breast reconstruction, rate of prosthetic reconstruction, and postoperative patient satisfaction so that scholars can understand the latest research progress of radiotherapy and breast reconstruction and clinicians can optimize therapeutic regimens.

Objective To investigate the early predictive value of several commonly used biochemical markers for predicting persistent organ failure ( POF ) in patients with hyperlipidemic acute pancreatitis ( HLAP) . Methods Clinical data of 157 patients with HLAP within 72 hours after the onset of first attack who were admitted to the Dept. of Gastroenterology in Changhai Hospital from January 2015 to December 2017 were retrospectively analyzed, including 106 cases without POF ( non POF group ) and 51 cases with POF ( POF group) . Hct, BUN, Cr, APACHEⅡand BISAP were recorded within 24 hours after admission. Receiver-operating characteristic ( ROC) curve was drawn to calculate area under the ROC curve ( AUC) and evaluate the performance of Hct, BUN, Cr, APACHEⅡand BISAP scores in predicting HLAP complicated with POF, which was compared by DeLong test. Results Values of BUN, Cr, APACHEⅡand BISAP were significantly higher in HLAP patients with POF than those without POF [(10. 30 ± 7. 43) vs (5. 34 ± 2. 26) mmol/L, (165. 31 ± 123. 93) vs (65. 61 ± 20. 82)μmol/L, (10. 22 ± 6. 22) vs (4. 61 ± 2. 99) points, (2. 61 ± 0. 87) vs (1. 42 ± 1.07) points], and the differences were all statistically significant (all P<0.05), whereas Hct was not significantly different between the two groups. The AUC of Cr and BUN for predicting POF was 0. 77(95％ CI, 0. 69-0. 86) and 0. 71 (95％ CI, 0. 61-0. 81), respectively, and the optimum predictive Cut-off values were 130 μmol/L and 8. 95 mmol/L, respectively. The sensitivity was 53％, and the specificity was 99％ and 94％;the accuracy was 84％ and 81％;negative predictive value was 81％, and positive predictive value was 96％ and 82％. DeLong test showed that predictive performance of BUN and Cr was not statistically different from that of APACHEⅡand BISAP. Conclusions Cr≥130 μmol/L and BUN≥8. 95 mmol/L can be used clinically to predict the presence of POF in HLAP, and the predictive efficacy were comparable to APACHEⅡand BISAP.