BACKGROUND:Bone tissue loss caused by tumors and trauma can have an adverse effect on postoperative rehabilitation.Therefore,scaffold materials are usually implanted during treatment.However,the existing implant materials are relatively simple and lack antibacterial properties.Early implantation may lead to iatrogenic autoinfection and have an adverse effect on osteogenesis.OBJECTIVE:To construct a KR-12-a5 polypeptide-nanohydroxyapatite-small intestinal submucosa composite scaffold and evaluate its feasibility as a material for promoting bone defect repair.METHODS:The small intestinal submucosa scaffold and the small intestinal submucosa scaffold containing 25,50,and 100 mg/mL nanohydroxyapatite(referred to as nHA-SIS scaffold)were prepared by 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride/N-hydroxysuccinimide cross-linking method.The appropriate scaffold was screened for subsequent experiments by mechanical property testing.The antibacterial properties of KR-12-a5 polypeptide solution against Staphylococcus aureus,Streptococcus gordonii,and Fusobacterium nucleatum were detected.The nHA-SIS scaffolds were immersed in 250,500,and 1 000 μg/mL KR-12-a5 peptide solutions for 24 hours,and then freeze-dried to obtain peptide-loaded nanohydroxyapatite-porcine small intestinal submucosa composite scaffolds(denoted as P-nHA-SIS scaffolds).The sustained-release properties of the three groups of scaffolds were characterized.The nHA-SIS scaffolds and the three groups of P-nHA-SIS scaffolds were co-cultured with Staphylococcus aureus,Streptococcus gordonii,and Fusobacterium nucleatum for 24 hours or 48 hours.The scaffolds with strong antibacterial ability were screened by live and dead bacteria staining and scanning electron microscopy for subsequent experiments.The degradation properties and water absorption rates of the uncross-linked small intestinal submucosa scaffolds,cross-linked small intestinal submucosa scaffolds,nHA-SIS scaffolds,and P-nHA-SIS scaffolds were characterized.The extracts of cross-linked small intestinal submucosal scaffolds,nHA-SIS scaffolds,and P-nHA-SIS scaffolds were co-cultured with MC3T3-E1 cells.CCK-8 assay and live-dead cell staining were performed.The effects of the extracts of the three scaffolds on the migration of MC3T3-E1 cells were detected by Transwell chamber assay.RESULTS AND CONCLUSION:(1)The elastic modulus and compressive strength of 25,50,and 100 mg/mL nHA-SIS scaffolds were higher than those of small intestinal submucosal scaffolds(P＜0.05),among which the elastic modulus and compressive strength of 25 mg/mL nHA-SIS scaffolds were the highest,and this group of scaffolds were selected for subsequent experiments to load peptides.(2)KR-12-a5 peptide had strong antibacterial activity against common bacteria in bone defects(Staphylococcus aureus,Streptococcus gordonii,and Fusobacterium nucleatum).The three groups of P-nHA-SIS scaffolds all had sustained release properties.With the increase of peptide mass concentration,the antibacterial property of P-nHA-SIS scaffold was enhanced.Among them,the P-nHA-SIS scaffold loaded with 500 μg/mL peptide had achieved a satisfactory antibacterial effect,and this group of scaffolds would be selected in the future.(3)The degradation rate of the three groups of cross-linked scaffolds was lower than that of the uncross-linked scaffolds,and the water absorption rate was greater than that of the uncross-linked scaffolds.P-nHA-SIS scaffolds could promote the proliferation and migration of MC3T3-E1 cells without affecting the activity of MC3T3-E1 cells.(4)The results show that P-nHA-SIS scaffolds have strong antibacterial properties and the ability to promote the proliferation and migration of MC3T3-E1 cells,and are expected to be used in bone defect repair.

BACKGROUND:Bone tissue loss caused by tumors and trauma can have an adverse effect on postoperative rehabilitation.Therefore,scaffold materials are usually implanted during treatment.However,the existing implant materials are relatively simple and lack antibacterial properties.Early implantation may lead to iatrogenic autoinfection and have an adverse effect on osteogenesis.OBJECTIVE:To construct a KR-12-a5 polypeptide-nanohydroxyapatite-small intestinal submucosa composite scaffold and evaluate its feasibility as a material for promoting bone defect repair.METHODS:The small intestinal submucosa scaffold and the small intestinal submucosa scaffold containing 25,50,and 100 mg/mL nanohydroxyapatite(referred to as nHA-SIS scaffold)were prepared by 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride/N-hydroxysuccinimide cross-linking method.The appropriate scaffold was screened for subsequent experiments by mechanical property testing.The antibacterial properties of KR-12-a5 polypeptide solution against Staphylococcus aureus,Streptococcus gordonii,and Fusobacterium nucleatum were detected.The nHA-SIS scaffolds were immersed in 250,500,and 1 000 μg/mL KR-12-a5 peptide solutions for 24 hours,and then freeze-dried to obtain peptide-loaded nanohydroxyapatite-porcine small intestinal submucosa composite scaffolds(denoted as P-nHA-SIS scaffolds).The sustained-release properties of the three groups of scaffolds were characterized.The nHA-SIS scaffolds and the three groups of P-nHA-SIS scaffolds were co-cultured with Staphylococcus aureus,Streptococcus gordonii,and Fusobacterium nucleatum for 24 hours or 48 hours.The scaffolds with strong antibacterial ability were screened by live and dead bacteria staining and scanning electron microscopy for subsequent experiments.The degradation properties and water absorption rates of the uncross-linked small intestinal submucosa scaffolds,cross-linked small intestinal submucosa scaffolds,nHA-SIS scaffolds,and P-nHA-SIS scaffolds were characterized.The extracts of cross-linked small intestinal submucosal scaffolds,nHA-SIS scaffolds,and P-nHA-SIS scaffolds were co-cultured with MC3T3-E1 cells.CCK-8 assay and live-dead cell staining were performed.The effects of the extracts of the three scaffolds on the migration of MC3T3-E1 cells were detected by Transwell chamber assay.RESULTS AND CONCLUSION:(1)The elastic modulus and compressive strength of 25,50,and 100 mg/mL nHA-SIS scaffolds were higher than those of small intestinal submucosal scaffolds(P＜0.05),among which the elastic modulus and compressive strength of 25 mg/mL nHA-SIS scaffolds were the highest,and this group of scaffolds were selected for subsequent experiments to load peptides.(2)KR-12-a5 peptide had strong antibacterial activity against common bacteria in bone defects(Staphylococcus aureus,Streptococcus gordonii,and Fusobacterium nucleatum).The three groups of P-nHA-SIS scaffolds all had sustained release properties.With the increase of peptide mass concentration,the antibacterial property of P-nHA-SIS scaffold was enhanced.Among them,the P-nHA-SIS scaffold loaded with 500 μg/mL peptide had achieved a satisfactory antibacterial effect,and this group of scaffolds would be selected in the future.(3)The degradation rate of the three groups of cross-linked scaffolds was lower than that of the uncross-linked scaffolds,and the water absorption rate was greater than that of the uncross-linked scaffolds.P-nHA-SIS scaffolds could promote the proliferation and migration of MC3T3-E1 cells without affecting the activity of MC3T3-E1 cells.(4)The results show that P-nHA-SIS scaffolds have strong antibacterial properties and the ability to promote the proliferation and migration of MC3T3-E1 cells,and are expected to be used in bone defect repair.

Objective To compare the intestinal injury induced by different intensities of waveshock in rats exposed to extremely cold environment and to preliminarily explore the characteristics of the injury.Methods Sixty healthy male SD rats(2 months old,weighing 200～250 g)were randomly divided into 6 groups(n=10):blank control group,low-temperature control group,5.0 MPa shock control group,and low-temperature+4.0,4.5 and 5.0 MPa shock groups.The rats in the experimental groups were pre-treated in a-10℃low-temperature environment for 30 min and then subjected to intestinal injury by using BST-I biological shock tube with different driving pressures.At 3,8,and 24 h after injury,the serum levels of IL-6,TNF-α,intestinal fatty acid binding protein(I-FABP),and diamine oxidase(DAO)were detected,and the survival of rats within 24 h was recorded.At 24 h after injury,the rats were anesthetized and dissected,the characteristics of intestinal injury were observed,and pathological examination was performed.The differences of intestinal injury were compared among the 6 groups to explore the characteristics of intestinal injuries after different intensities of shockwave in rats after exposure to extremely cold environment.Results Compared with the blank control group,the other 5 groups exhibited different severities of intestinal injury,and the rats in the low-temperature+different shock groups were more prone to intestinal edema and trauma.The mortality rate was significantly increased in the low-temperature+5.0 MPa shock group(P<0.05).Pathological and serological studies found that dual effects of very cold environment and blast injury resulted in intestinal mucosal hemorrhage,edema,and disintegration of lamina propria in the experimental rats.The indicators of intestinal mucosal injury and intestinal inflammatory factors were also significantly increased when compared with the blank control group,and significant differences were among the groups with increment of shock intensity(P<0.05).Conclusion Exposure to very cold environment combined with abdominal blast injury increases mortality rate in rats,manifested by elevated serological indicators and intestinal inflammatory factors,as well as varying severities of intestinal wall edema and submucosal bleeding.Furthermore,the severity of the injury is positively related to the impact intensity,with worsened as the impact intensity increasing.

Women with infertility, as a group with special needs, are affected by intimate partner violence (IPV) , which influences both the progression of their disease and their mental health. This article reviews the concept of IPV, the prevalence of IPV in women with infertility, assessment tools, and influencing factors, aiming to provide a reference for developing appropriate intervention programs.

Women with infertility, as a group with special needs, are affected by intimate partner violence (IPV) , which influences both the progression of their disease and their mental health. This article reviews the concept of IPV, the prevalence of IPV in women with infertility, assessment tools, and influencing factors, aiming to provide a reference for developing appropriate intervention programs.

The accumulation of fatigue during military operations may lead to decreased operational efficiency and non-combat attrition,which can impact combat effectiveness.On-site monitoring and evaluation of fatigue during military operations,as an important means to keep track of military operations and bring about quick changes in training,underlie the combat effectiveness of military personnel.Focusing on the on-site monitoring and evaluation methods of fatigue during military operations,this paper reviews the determinants of such fatigue as well as on-site monitoring and comprehensive evaluation methods so as to provide reference for accurate and efficient evaluation of fatigue during military operations and for early warning of such fatigue.

Objective:To investigate the perioperative alterations and management of coagulation function in patients of massive blood transfusion during retroperitoneal tumor (RT)resection.Methods:Fourty-seven RT patients at Peking University International Hospital from Jan 2016 to Dec 2021 undergoing resection with massive blood transfusion more than 20 U within 24 h were reviewed for coagulation function before and after surgery.Results:Intraoperative bleeding was 3 000-25 800 ml, 10 patients had blood loss ≥10 000 ml. During the operation, (25.3±9.9) U of red blood cells were transfused, (2 720±1 369) ml plasma transfused, and (2.4±3.3) U platelets were transfused in 6 patients. Fourty-five patients received intraoperative albumin of (79.5±46.5) g; All 47 patients received fibrinogen of (2.3±1.3) g; Prothrombin complex was given in 45 patients (1 205±807) U. Preoperative hemoglobin was statistically different compared to postoperatively and days 1, 3 and 5 ( W=1 790, P<0.001; W=1 672, P<0.001; W=1 704, P<0.001; W=1 486, P=0.004);As with platelets, the difference was also statistically significant compared to postoperative days 1, 3, and 5 ( W=2 153, P<0.001; W=2 092, P<0.001; W=1 732, P<0.001); Preoperative albumin was different compared to postoperative days 1 and 3 ( W=1 568, P<0.001; W=1 578, P<0.001,); Preoperative fibrinogen was different compared to postoperative day 1 ( W=1 964, P<0.001). PT and APTT were prolonged on postoperative days 1 and 3 ( W=628, P<0.001, W=804, P=0.023) ( W=661, P<0.001, W=796, P=0.02). Patient's preoperative fibrin degradation products and D-dimer were above the normal value and were higher on postoperative days 3 and 5 ( W=498, P<0.001, W=345, P<0.001). Conclusions:Coagulation disorders occur perioperatively in patients with massive transfusion while undergoing surgery for RT.The implementation of ratiional transfusion strategy and close postoperative survey and management of coagulation dysfunction help avoid the coagulation related morbidities.

Objective:To provide references for achieving long time continuous monitoring of cardiac functional changes of astronauts in spaceflight activities through continuously noninvasive assessment of left ventricular systolic function under exercise load by wearable cardiac sounds and ECG signals synchronization monitoring technology.Methods:Eleven healthy male youths were recruited for the study, and they did incremental load exercise on the recumbent power bicycle, starting at 50 W, increasing by 25 W every 3 minutes, until the maximum of 125 W reached. The subjects′ cardiac sounds and ECG signals at rest, 1 min after each level of load during exercise and 3 min after the end of exercise were selected; the transthoracic cardiac ultrasound examination of subjects was performed before and 5 min after exercise. The correlation between the cardiac sounds and ECG signals and left ventricular ejection fraction (LVEF) was analyzed, and a regression model was established to predict LVEF during exercise.Results:There were significant differences in heart rate, LVEF, electro-mechanical activation time (EMAT) and left ventricular ejection time (LVET) of subjects under different exercise loads ( F=53.22, 45.33, 3.65, 23.19, P<0.001, <0.001, =0.011, <0.001). Compared with the resting state, subjects showed increased heart rate and LVEF and a decreased EMAT and LVET during exercise loading, all of which were statistically significant ( P<0.01 or 0.05). In the correlation analysis, LVEF was negatively correlated with EMAT and LVEF ( r=-0.415, -0.758, P=0.002,<0.001), and positively correlated with the amplitude of the first heart sound ( r=0.606, P<0.001). The model for predicting LVEF was established by EMAT and LVET, and the multiple regression model was LVEF=108.698-0.092×LVET-0.134×EMAT ( r=0.87, P<0.001). Conclusions:The synchronous monitoring technology of cardiac sounds and ECG signals can continuously and non-invasively monitor LVEF changes during exercise. LVET is the most closely related to LVEF. LVEF is hopeful to predict the changes of cardiac function of astronauts in spaceflight activities.

Objective:To provide references for achieving long time continuous monitoring of cardiac functional changes of astronauts in spaceflight activities through continuously noninvasive assessment of left ventricular systolic function under exercise load by wearable cardiac sounds and ECG signals synchronization monitoring technology.Methods:Eleven healthy male youths were recruited for the study, and they did incremental load exercise on the recumbent power bicycle, starting at 50 W, increasing by 25 W every 3 minutes, until the maximum of 125 W reached. The subjects′ cardiac sounds and ECG signals at rest, 1 min after each level of load during exercise and 3 min after the end of exercise were selected; the transthoracic cardiac ultrasound examination of subjects was performed before and 5 min after exercise. The correlation between the cardiac sounds and ECG signals and left ventricular ejection fraction (LVEF) was analyzed, and a regression model was established to predict LVEF during exercise.Results:There were significant differences in heart rate, LVEF, electro-mechanical activation time (EMAT) and left ventricular ejection time (LVET) of subjects under different exercise loads ( F=53.22, 45.33, 3.65, 23.19, P<0.001, <0.001, =0.011, <0.001). Compared with the resting state, subjects showed increased heart rate and LVEF and a decreased EMAT and LVET during exercise loading, all of which were statistically significant ( P<0.01 or 0.05). In the correlation analysis, LVEF was negatively correlated with EMAT and LVEF ( r=-0.415, -0.758, P=0.002,<0.001), and positively correlated with the amplitude of the first heart sound ( r=0.606, P<0.001). The model for predicting LVEF was established by EMAT and LVET, and the multiple regression model was LVEF=108.698-0.092×LVET-0.134×EMAT ( r=0.87, P<0.001). Conclusions:The synchronous monitoring technology of cardiac sounds and ECG signals can continuously and non-invasively monitor LVEF changes during exercise. LVET is the most closely related to LVEF. LVEF is hopeful to predict the changes of cardiac function of astronauts in spaceflight activities.

Objective To investigate the expression of hsa_circ_0018574 in colorectal cancer tissues and human colon cancer HT29 cell line, as well as its effect on the proliferation and apoptosis of colorectal cancer cells. Methods The circPrimer 1.2 software was used to draw the circRNA sequence structure. Meanwhile, the circRNA microarray was used to screen differentially-expressed circRNA in colorectal cancer tissues and adjacent tissues, and RNA was extracted from tissue samples. The expression of hsa_circ_0018574 in human colorectal tumors was detected by RT-qPCR. The si-circ_0018574 was transfected into HT29 cells, and the expression of CDK2, CDK4, CDK6, cyclinD1, and cyclinE cyclins were detected by colony formation assay, flow cytometry, and Western blot, respectively. Results The expression of hsa_circ_0018574 in human colorectal tumor tissues was significantly higher than that in adjacent tissues (P < 0.01). Meanwhile, the si-circ_0018574 in HT29 cells could significantly inhibit the proliferation of cancer cells, reduce clone formation and colony formation ability (P < 0.01), and induce tumor cell apoptosis (P < 0.01). The expressions of CDK2, CDK4, CDK6, cyclinD1 and cyclinE cyclins were decreased. Conclusion The hsa_circ_0018574 is highly expressed in colorectal tumors, and si-circ_0018574 could significantly inhibit the proliferation of HT29 cells, reduce cell division, and induce apoptosis.