BACKGROUND:Osteoporotic fracture is the most serious complication of osteoporosis.Previous studies have demonstrated that gut microbiota has a regulatory effect on skeletal tissue and that gut microbiota has an important relationship with osteoporotic fracture,but the causal relationship between the two is unclear. OBJECTIVE:To explore the causal relationship between gut microbiota and osteoporotic fractures using Mendelian randomization method. METHODS:The genome-wide association study(GWAS)datasets of gut microbiota and osteoporotic fracture were obtained from the IEU Open GWAS database and the Finnish database R9,respectively.Using gut microbiota as the exposure factor and osteoporotic fracture as the outcome variable,Mendelian randomization analyses with random-effects inverse variance weighted,MR-Egger regression,weighted median,simple model,and weighted model methods were performed to assess whether there is a causal relationship between gut microbiota and osteoporotic fracture.Sensitivity analyses were performed to test the reliability and robustness of the results.Reverse Mendelian randomization analyses were performed to further validate the causal relationship identified in the forward Mendelian randomization analyses. RESULTS AND CONCLUSION:The results of this Mendelian randomization analysis indicated a causal relationship between gut microbiota and osteoporotic fracture.Elevated abundance of Actinomycetales[odds ratio(OR)=1.562,95%confidence interval(CI):1.027-2.375,P=0.037),Actinomycetaceae(OR=1.561,95%CI:1.027-2.374,P=0.037),Actinomyces(OR=1.544,95%CI:1.130-2.110,P=0.006),Butyricicoccus(OR=1.781,95%CI:1.194-2.657,P=0.005),Coprococcus 2(OR=1.550,95%CI:1.068-2.251,P=0.021),Family ⅩⅢ UCG-001(OR=1.473,95%CI:1.001-2.168,P=0.049),Methanobrevibacter(OR=1.274,95%CI:1.001-1.621,P=0.049),and Roseburia(OR=1.429,95%CI:1.015-2.013,P=0.041)would increase the risk of osteoporotic fractures in patients.Elevated abundance of Bacteroidia(OR=0.660,95%CI:0.455-0.959,P=0.029),Bacteroidales(OR=0.660,95%CI:0.455-0.959,P=0.029),Christensenellacea(OR=0.725,95%CI:0.529-0.995,P=0.047),Ruminococcaceae(OR=0.643,95%CI:0.443-0.933,P=0.020),Enterorhabdus(OR=0.558,95%CI:0.395-0.788,P=0.001),Eubacterium rectale group(OR=0.631,95%CI:0.435-0.916,P=0.016),Lachnospiraceae UCG008(OR=0.738,95%CI:0.546-0.998,P=0.048),and Ruminiclostridium 9(OR=0.492,95%CI:0.324-0.746,P=0.001)would reduce the risk of osteoporotic fractures in patients.We identified 16 gut microbiota associated with osteoporotic fracture by the Mendelian randomization method.That is,using gut microbiota as the exposure factor and osteoporotic fracture as the outcome variable,eight gut microbiota showed positive causal associations with osteoporotic fracture and another eight gut microbiota showed negative causal associations with osteoporotic fracture.The results of this study not only identify new biomarkers for the early prediction of osteoporotic fracture and potential therapeutic targets in clinical practice,but also provide an experimental basis and theoretical basis for the study of improving the occurrence and prognosis of osteoporotic fracture through gut microbiota in bone tissue engineering.

BACKGROUND:Due to the mismatch between the design of the proximal femoral nail antirotation Asian version(PFNA-Ⅱ)and Asian population,extrusion of the proximal femoral intertrochanteric nail may occur in the treatment of femoral intertrochanteric fractures.The influence of the protruding length on the curative effect of the operation needs to be further discussed. OBJECTIVE:To quantitatively measure the protruding length of the proximal trochanter of the femur with intramedullary nail after PFNA-Ⅱ,and to analyze the effect of protruding length on the efficacy of PFNA-Ⅱ in the treatment of femoral intertrochanteric fractures. METHODS:Totally 68 patients with femoral intertrochanteric fractures treated with PFNA-Ⅱ internal fixation in the First Affiliated Hospital of Anhui Medical University were selected.The extramedullary process of the proximal trochanter of the femur was quantitatively measured on the anterior and posterior X-ray films of the hip joint within 6 months after operation.According to the existence of extrusion of the proximal trochanter intramedullary nail,the patients were divided into protruding group and non-protruding group.The data of sex,height,fracture type,length and diameter of the intramedullary nail,the position of screw blade in the femoral neck and protruding length of proximal greater trochanter were collected.The postoperative curative effect was judged by visual analog scale pain score and hip joint Harris score at 6 months after operation.The influence of protruding proximal trochanter of the PFNA-Ⅱ intramedullary nail on the operative effect was observed. RESULTS AND CONCLUSION:(1)There were significant differences in sexual characteristics between the protruding group and the non-protruding group(P=0.001).(2)According to AO/OTA classification,there were no significant differences in fracture type between the protruding group and the non-protruding group(P=0.289).(3)There was no significant difference in the length and diameter of the intramedullary nail between the two groups(P=0.067,P=1.000).(4)There was no significant correlation between the height of all patients and the length of the intramedullary nail(P=0.510),but there was a significant correlation between height and protruding length(P=0.034).There was no significant correlation between screw blade position and protruding length(P=0.968).(5)Six months after operation,there was no significant difference in the hip Harris score(P=0.373),but the visual analog scale pain score was significantly higher in the protruding group than that in the non-protruding group(P=0.000).(6)The results suggest that nail extrusion often occurs in the proximal greater trochanter when PFNA-Ⅱ is used in the treatment of intertrochanteric fractures in Asians.When the nail extended into the proximal soft tissue of the greater trochanter,patients complained of proximal greater trochanteric pain and the visual analog scale score of proximal greater trochanter pain in the patient was significantly higher than that in the non-protruding group.To be more suitable for the Asian population,we suggest that the PFNA-Ⅱ should be improved to further shorten the proximal nail end to obtain better clinical results of femoral intertrochanteric fracture fixation.

BACKGROUND:Heart rate variability biofeedback is a respiratory training method that uses slow and deep breathing at the resonant frequency to induce rhythmic,high-amplitude oscillations in the cardiovascular system,thereby stimulating and exercising the autonomic and baroreflex.However,current studies have not systematically reviewed how heart rate variability biofeedback modulates the autonomic function and produces effects.There is a lack of public understanding of the mechanism of heart rate variability biofeedback,and its application progress and scheme are not fully understood. OBJECTIVE:To review the existing experimental studies on the effects of heart rate variability biofeedback on symptoms in different populations at home and abroad and to introduce the mechanisms and advances in the application of heart rate variability biofeedback to modulate the autonomic nervous system. METHODS:"Heart rate variability biofeedback,resonance breathing,heart rate variability,autonomic nerve,breathing training,chronic diseases,mental illness,biofeedback"were used as Chinese or English keywords to search in CNKI,WanFang Database,PubMed,and Web of Science.A total of 72 core related papers were included according to the inclusion and exclusion criteria. RESULTS AND CONCLUSION:The body's oscillation system and resonance system are essential for the effectiveness of heart rate variability biofeedback.Oscillations reflect the response to external stimuli and self-regulating reflex systems,while resonances involve synchronous oscillations that result in higher amplitude operations.The balance between sympathetic and parasympathetic nerves is crucial for maintaining a stable internal environment.Autonomic nervous system disorders are associated with reduced heart rate variability and are closely linked to the progression of related diseases.Heart rate variability biofeedback utilizes the resonance characteristics of the cardiovascular system,inducing rhythmic high-amplitude oscillations by employing deep slow breathing at the resonance frequency.This method improves the regulatory function of the sympathetic and parasympathetic system reflexes and enhances the balance regulation between the two systems.Two major mechanisms of cardiovascular system resonance are the baroreflex closed-loop pathway and respiratory sinus arrhythmia.These mechanisms,along with the unique delay of baroreflex,result in a 0° phase angle oscillation between heart rate and respiration and a 180° phase angle oscillation between blood pressure and respiration during breathing at the resonant frequency rhythm.Periodically stimulating the human cardiovascular oscillation system through this method is an easy-to-operate and effective training approach.Currently,heart rate variability biofeedback is mainly applied in the fields of mental illness,chronic disease,and sports.However,the intervention mechanism and efficacy are unclear,the intervention content,frequency and duration are varied,and there are limited review studies on the intervention methods tailored to different types of individuals.As a non-drug and non-invasive intervention,heart rate variability biofeedback can significantly increase heart rate variability,regulate the balance between sympathetic and parasympathetic nerves,and improve the stability and adaptability of the autonomic nervous system.In the future,it is suggested to investigate the mechanisms and potential applications of the pathways of the heart rate variability biofeedback that induce cardiovascular resonance.It is also recommended to incorporate long-term follow-ups to assess the sustained value of heart rate variability biofeedback in various fields.This would provide new directions and strategies for the comprehensive treatment of complex diseases.

Objective:To construct a double-layer bone-on-a-chip containing bone matrix, with which the process of osteoblast and osteoclast differentiation in vitro is stimulated, aiming to provide a new platform for the development of osteoporosis medications. Methods:Software WorkSoild was used to design the double-layer and double-channel bone-on-a-chip and the template was fabricated by photolithography. With polydimethylsiloxane (PDMS) as the raw material, the main body of the chip was prepared by mold fabrication. The inlets and outlets of the four channels of the culture room were separated with bovine cortex bones and sealed with liquid storage columns. In the chip verification experiment, chips were divided into osteogenic and osteoclastic induction groups and osteogenic and osteoclastic control groups. In the osteogenic and osteoclastic induction groups, precursor cells of mouse embryonic osteoblast, MC3T3-E1 and mouse macrophage RAW264.7 were inoculated on the chip separately. Osteogenic induction lasted 14 days and osteoclastic induction 7 days. MC3T3-E1 cells and RAW264.7 cells were not induced in the osteogenic and osteoclastic control groups. The following indicators were observed: (1) Appearance and sealing performance of the chip: After the chip was prepared, photos were taken to observe its appearance and sealing tests were conducted to observe its sealing performance. (2) Biocompatibility: At 3 days after MC3T3-E1 cells were inoculated onto the chip and cultured and at 1, 3 and 5 days after RAW264.7 cells were inoculated onto the chip and cultured, the cell survival was observed with calcein acetoxymethyl ester/propidium iodide (AM/PI) staining and Cell Counting Kit 8 (CCK-8). (3) Osteogenic differentiation: Alkaline phosphatase (ALP) staining and alizarin red staining were performed on the cells in the osteogenic induction group to observe the osteogenic induction. RNA was collected from the osteogenic induction group and the osteogenic control group, the expression of osteoblast marker Runt-related transcription factor 2 (RUNX2), osteocalcin (OCN) and type I collagen (COL1A1) was detected by real-time florescent quantitative PCR (qPCR), and the differentiation degree and osteogenic ability of osteoblasts were observed. (4) Osteoclast differentiation: tartrate-resistant acid phosphatase (TRAP) staining was performed on cells in the osteoclastic induction group to observe osteoclast differentiation. RNA was extracted from the osteoclastic induction group and the osteoclastic control group for qPCR of osteoclast differentiation-related genes, and the expression levels of the osteoclast marker gene TRAP, cathepsin K (CTSK) and dendritic cell specific transmembrane protein (DC-STAMP) were detected.Results:The double-layer bone-on-a-chip containing bone matrix was 3 cm×3 cm in size and transparent as a whole. The structure of the system on the chip system was compact and had no seepage. It was shown by calcein AM/PI staining that at 3 days after MC3T3-E1 cells and RAW264.7 cells were cultured, very few red fluorescent dead cells were found. CCK-8 test showed that within 5 days after being cultured, the cell viability was all above 90%, indicating that the biocompatibility of the chip was good and the cells could survive and proliferate normally. The results of ALP and alizarin red staining showed that MC3T3-E1 cells successfully differentiated into osteoblasts and produced calcified nodules in the osteogenic induction group at 14 days after the induction. The qPCR results showed that the relative expression level of RUNX2 in MC3T3-E1 cells in the osteogenic induction group was 4.98±0.74, which was significantly higher than that of the control group (0.99±0.03) ( P<0.01). The relative expression level of OCN in MC3T3-E1 cells was 7.98±0.76, which was significantly higher than that of the control group (1.00±0.06) ( P<0.01). The relative expression level of COL1A1 in MC3T3-E1 cells was 7.07±0.56, which was significantly higher than that of the control group (0.97±0.03) ( P<0.01). The TRAP staining results showed that the RAW264.7 cells in the osteoclastic induction group differentiated to giant multinucleated osteoclasts, and TRAP protein was expressed in large quantity in the osteoclasts. The results of qPCR showed that the relative expression level of TRAP in RAW264.7 cells in the osteoclastic induction group was 3.35±0.37, which was significantly higher than that of the control group (1.01±0.06) ( P<0.01). The relative expression level of CTSK in RAW264.7 cells was 3.46±0.79, which was significantly higher than that of the control group (1.01±0.05) ( P<0.01). The relative expression level of DC-STAMP in RAW264.7 cells was 1.92±0.12, which was significantly higher than that of the control group (0.98±0.08) ( P<0.01). Conclusions:The double-layer bone-on-a-chip containing bone matrix is compact in structure, can be cultured in vitro for a long time, has good biocompatibility and can be used for inducing osteogenic and osteoclast differentiation. Therefore, it is expected to provide a new research platform for exploring the mechanism of osteoporosis and medication screening.

Objective To compare the efficacy of TightRope loop plate and Endobutton plate in the treatment of acromioclavicular joint dislocation.Methods A retrospective analysis was conducted on 94 patients with acromioclavicular joint dislocation who were treated at this center from March 2021 to February 2023.They were divided into two groups based on different admission date.The Group E(n =47)received Endobutton plate treatment between March 2021 and February 2022,while the Group T(n =47)received TightRope loop plate treatment between March 2022 and February 2023.At the last follow-up,the perioperative indicators,Visual Analogue Scale(VAS),Constant-Murley shoulder joint function scores,and surgical complications were compared between the two groups.Results The surgical time,intraoperative bleeding,incision length,and VAS scores at 7 days after surgery in the Group T were shorter or lower than those in the Group E(P<0.05).There were no statistical differences in the incidence of perioperative nerve injury,internal fixation displacement,clavicle fracture,vascular injury,and infection between the two groups(P>0.05).The subjective and objective scores of Constant-Murley shoulder joint function in both groups at9 months after surgery showed significant improvement compared to preoperative scores(all P =0.000).There was no significant difference in the subjective and objective scores of Constant-Murley shoulder joint function between the two groups at 9 months after surgery(P>0.05).Conclusions The treatment of acromioclavicular joint dislocation with TightRope loop plate ot or Endobutton plate has a significant effect and can effectively improve shoulder joint function.Compared with Endobutton plate,use of TightRope loop plate has minor surgical trauma,less bleeding,and significantly reduced postoperative pain,being more conducive to early functional exercise for patients.

Objective:To understand the situation and epidemic characteristics of injury deaths among children aged 5 to 24 years in Jiangsu Province from 2012 to 2021 and the trend of annual changes.Methods:The main injury mortality data of children and adolescents was collected, and the crude and standardized mortality rates of road traffic accidents, drowning, suicide, and accidental falls among children and adolescents over a decade and the annual average percentage of change (AAPC) were calculated. The main injury mortality characteristics and trends of children and adolescents of different age groups and genders were analyzed.Results:The total number of injury deaths among 5 to 24 adolescents in Jiangsu Province was 16 052, with a standardized mortality rate of 9.58/100 000. There was no significant trend in the overall standardized mortality rate of injuries (AAPC=-3.450%, P=0.055). The standardized mortality rate of road traffic injuries among children and adolescents showed a decreasing trend over the past decade, with statistical significance (AAPC=-9.406%, P<0.001). The standardized suicide mortality rate showed an upward trend over the past decade, with statistical significance (AAPC=9.000%, P=0.001). The overall injury mortality rate showed an upward trend with age. Suicide rates in males and females were on the rise and both have statistical significance (AAPC=9.420% and AAPC=9.607%, both P<0.05). The standardized mortality rates of female traffic accidents, drowning, and male traffic accidents showed a decreasing trend and were statistically significant (AAPC for female traffic accidents=-7.364%, AAPC for female drowning=-5.352%, and AAPC for male traffic accidents=-10.242%, all P<0.05). The standardized mortality rate of urban and rural traffic accidents showed a decreasing trend and was statistically significant(AAPC=-7.899% and AAPC=-9.421%, both P<0.001). The standardized suicide mortality rate showed an upward trend and statistical significance (AAPC=11.009% and AAPC=7.528%, both P<0.05). Conclusions:The overall injury situation of children and adolescents in Jiangsu Province improved in the past decade from 2012 to 2021, but the suicide mortality rate was on the rise. It is necessary to focus on the mental health issues of this age group and to strengthen the prevention and control of suicide among children and adolescents, in Jiangsu.

Objective: To screen dynamic cardiorespiratory fitness indices for effective assessment of aerobic endurance using incremental load exercise tests. Methods: From March to November 2019, 266 volunteers who were able to understand the trial and voluntarily cooperated with the entire testing process were randomly recruited from 5 universities in Beijing. Gas metabolism and cardiac function were monitored in real time using the German Cortex Metalyzer 3B system and the US Cheetah NICOM system, and maximum oxygen uptake was measured by a linear incremental loading scheme. Aerobic endurance and dynamic cardiopulmonary function indices were selected according to the study design, and the relationship between the two indicators was analyzed using correlation and typicality correlation. Results: The absolute maximum oxygen uptake (VO 2max ), relative maximum oxygen uptake, maximum stroke volume (SV max ), and maximum stroke volume index (SVI max ) were significantly higher in males than in females, and the dynamic cardiopulmonary function index K was significantly lower than in females ( t =17.8, 10.1, 8.5, 4.3 , -6.3, P < 0.05 ). Simple correlation revealed that absolute VO 2max and relative VO 2max were negatively correlated with K and b, and absolute VO 2max and relative VO 2max were positively correlated with SV max and SVI max ( P <0.01); Both dynamic cardiopulmonary function indices were significantly correlated with aerobic endurance. Aerobic endurance indexes closely related to dynamic cardiopulmonary function were absolute VO 2max , relative VO 2max ; dynamic cardiopulmonary function indexes closely related to aerobic endurance were K, b, SV max , SVI max . Conclusion Improvement of dynamic cardiorespiratory fitness contributes to the improvement of aerobic endurance, the dynamic cardiorespiratory fitness indices K, b, SV max , and SVI max can be used as important candidates to predict the assessment of aerobic exercise capacity.

Objective:To analyze the cause and epidemiological characteristics of an outbreak of cutaneous anthrax in Caoxian County, Heze City, Shandong Province, and to provide scientific basis for anthrax prevention and control.Methods:Using on-site epidemiological investigation methods and the "Anthrax Epidemiological Case Investigation Form", case investigations were conducted based on the epidemiological contact history and close contacts of suspected anthrax cases reported by the national health care system ( n = 83). Scorched skin smears, diseased cattle tissues, soil samples from the slaughter site and smears from slaughter utensils were collected from cases for Real-time PCR testing and pathogenic bacteria isolation and culture, respectively. Anthrax determination criteria were carried out with reference to "Anthrax Diagnosis" (WS 283-2020). Results:A total of 13 cases of cutaneous anthrax were found in this outbreak, including 12 clinically diagnosed cases and one confirmed case (positive Real-time PCR test and isolation of a strain of Bacillus anthracis). The epidemiological investigation determined that the source of infection in this outbreak was diseased cattle, the transmission route was through slaughter of diseased cattle, contact with contaminated utensils and related cattle products, and the patients were mainly engaged in occupations related to cattle slaughter or cattle product collection and sale. A total of 84 samples were collected, including 13 skin scabs, 64 environmental samples and 7 beef samples. Thirty-six positive PCR tests were performed, with a positive rate of 42.86% (36/84). Among them, 100.00% (13/13) were positive for skin scab smear specimens, 29.69% (19/64) for environmental samples and 4/7 for beef samples. A total of 8 strains of Bacillus anthracis were isolated, including 6 environmental specimens, 1 suspected case and 1 beef strain, with an overall detection rate of 9.52% (8/84). Eighty-three close contacts were investigated. Thirteen households involved in the epidemic were disinfected by spraying (200 ml/m 2) with chlorine-containing disinfectant (5 000 mg/L), and a total of 40 households involved in the epidemic were disinfected, covering an area of about 10 765 m 2. Forty-five pieces of suspected contaminated clothing were burned and disposed of, and 152 pieces of kitchenware were soaked. Conclusions:Slaughter of infected cattle, contact with contaminated utensils and related cattle products are the main causes of this skin anthrax outbreak. Strengthening market supervision, deepening inter-animal epidemic prevention, carrying out publicity and education on anthrax prevention and control, and enhancing practitioners' awareness of disease prevention is the key to prevent anthrax from occurring.

Circadian Clocks/genetics* ; Reactive Oxygen Species ; Methionine ; Gastrointestinal Microbiome ; Gastrointestinal Tract ; Racemethionine ; Gene Expression

Objective:To design and construct a bone nonunion organoid on chip and explore the mechanism of aseptic bone nonunion.Methods:First a semi-open microfluidic chip was designed, on which human bone marrow mesenchymal stromal cells (BMSC), human fetal lung fibroblast 1, (HFL1) and human umbilical vein endothelial cells (HUVEC) were co-cultured, and a three-dimensional organ on chip system was established. Different proportions of HFL1 and HUVEC were co-cultured with BMSC, which were divided into the control group (HFL1∶HUVEC=1∶1), the fibrosis group (HFL1∶HUVEC=3∶1) and the vascularization group (HFL1∶HUVEC=1∶3). The osteogenic differentiation of BMSC was observed by alkaline phosphatase (ALP) and Alizarin red staining. The transcription level of osteogenic marker genes SP7, RUNX2, ALPL, and BGLAP, and vascularization related genes KDR and VWF were analyzed by qPCR. The expression levels of RUNX2 and ALP were determined by Western Blot. Results:In the co-culture system of BMSCs, HFL1, and HUVECs, BMSCs exhibited normal growth and apparent biomineralization behavior. Endothelial cells were capable of forming structured vascular networks, confirming the successful establishment of the system. Compared to the baseline group, the fibrotic group showed no significant decrease in BMSC osteogenic differentiation. The relative expression levels of the mineralization marker genes ALPL and BGLAP were 0.55±0.19 ( P<0.001) and 0.42±0.27 ( P<0.001), respectively. Vascularization genes KDR and VWF were downregulated, with relative expression levels of 0.49±0.17 ( P<0.001) and 0.49±0.21 ( P<0.001). In contrast, in the vascularized group, BMSC osteogenic differentiation genes SP7, RUNX2, ALPL, and BGLAP were upregulated, with relative expression levels of 2.91±0.52 ( P<0.001), 3.83±1.87 ( P<0.001), 3.22±1.29 ( P<0.001), and 5.21±1.46 ( P<0.001), respectively. Vascularization genes KDR and VWF were also upregulated, with relative expressions of 8.24±2.84 ( P<0.001) and 5.32±1.67 ( P<0.001). Western blot results indicated increased expression of RUNX2 and ALP in the vascularized group and decreased expression in the fibrotic group. Conclusion:The bone nonunion organoid on chip could partially simulate the local microenvironment of bone nonunion. Fibrosis may lead to a significant decrease in bone formation ability and vascularization level, which might be an important reason for the occurrence of aseptic bone nonunion.