BACKGROUND:Streptococcus mutans is an important pathogen of dental caries,and timely detection of its levels is of great significance for early detection and treatment of dental caries. OBJECTIVE:To evaluate the effect of loop-mediated isothermal amplification(FTA-LAMP)direct extraction of Streptococcus mutans DNA. METHODS:(1)Bacterial suspensions containing ATCC standard strains(Streptococcus mutans)were prepared and inoculated into the brain-heart leachate medium.After mixed thoroughly,the mixture was then diluted in a 10-fold gradient into seven concentrations(4.2×107,4.2×106,4.2×105,4.2×104,4.2×103,4.2×102,4.2×10 CFU/mL),two parallel controls were made for each dilution level,and sterile water was used as a blank control.(2)The DNA of Streptococcus mutans was extracted using FTA Elute card,boiling method,kit extraction and lysate extraction methods separately and then amplified using LAMP technology was amplified.A specificity test was also performed to compare the differences between the four DNA extraction methods.RESULTS AND CONCLUSION:The DNA extracted by all four methods met the requirements for LAMP amplification.Specificity test results showed that only Streptococcus mutans could specifically amplify the target gene.The detection limit value of the DNA concentration was 4.2×103 CFU/mL for the lysate method,4.2×104 CFU/mL for the FTA Elute card extraction method,4.2×106 CFU/mL for the kit extraction method,and 4.2×107 CFU/mL for the boiling method.In the other aspects of the four extraction methods,the kit extraction method had the highest experimental cost,number of steps and time;the other three methods had the same number of steps,with the FTA Elute card method requiring the least amount of instruments,the boiling method having the lowest single cost,and the lysate extraction method taking the least amount of time.Only a small amount of bacteria were needed for successful extraction using both the FTA Elute card and lysate extraction methods.Compared with the FTA Elute card method,the lysate extraction method was superior in terms of time,but it had a high single cost and required more equipment.To conclude,the FTA-LAMP technology established in this study has the advantages of ease of operation,high specificity,high sensitivity,and visualization,which is expected to be a new way for efficient extraction and detection of Streptococcus mutans.

BACKGROUND:Eucommia ulmoides has a certain osteogenic effect,which can promote the proliferation and differentiation of osteoblasts.However,it is unclear whether Eucommia ulmoides has effects on alveolar bone formation and Wnt/β-Catenin signaling pathway. OBJECTIVE:To investigate the mechanism by which Eucommia ulmoides promotes alveolar bone formation in ovariectomized rats based on the Wnt/β-Catenin signaling pathway. METHODS:Sixty female Sprague-Dawley rats were selected and randomly divided into five groups:blank control group,sham-operation group,model group,low-dose group Eucommia ulmoides group,and high-dose Eucommia ulmoides group,with twelve rats in each group.Osteoporosis animal models were constructed by bilateral oophorectomy in the model group and the low-dose and high-dose Eucommia ulmoides groups.The sham-operation group underwent the same method to remove adipose tissue of equal mass around the bilateral ovaries.Three months after surgery,the low-and high-dose Eucommia ulmoides groups were given 2.1 g/kg/d and 4.2 g/kg/d Eucommia ulmoides by gavage,respectively.The sham-operation group and model group were given the same amount of physiological saline by gavage.After 12 weeks of drug intervention,the changes in alveolar bone mass of rats in each group were observed through Micro-CT;hematoxylin-eosin staining was used to observe the pathological structural changes of alveolar bone in rats;enzyme linked immunosorbent assay was used to detect the expression levels of alkaline phosphatase and osteocalcin in the serum of rats;western blot was used to detect the expression levels of β-Catenin and Frizzled9 receptor proteins in the alveolar bone of rats;and real-time fluorescence quantitative PCR was used to detect the expression of osteocalcin,Runt-related transcription factor 2(Runx2),alkaline phosphatase,β-catenin,and frizzled9 mRNAs in alveolar bone tissues of rats. RESULTS AND CONCLUSION:Compared with the blank control group,bone volume fraction,trabecular number,trabecular thickness,and bone mineral density were reduced in the model group(P＜0.05),and trabecular separation was elevated(P＜0.05).Pathological observation showed that the arrangement of trabeculae was disordered and irregular,the trabeculae were thinned or broken,and the marrow cavity was enlarged in the model group,with a significant reduction in bone volume;the level of alkaline phosphatase in the serum was increased(P＜0.05),and the level of osteocalcin was decreased(P＜0.05);mRNA expression of alkaline phosphatase,osteocalcin,Runx2,β-catenin,and frizzled9 were decreased(P＜0.05);protein expression of β-Catenin and Frizzled9 was decreased(P＜0.05).Compared with the model group,the low-and high-dose Eucommia ulmoides groups showed an increase in bone volume fraction,trabecular number,trabecular thickness,and bone mineral density(P＜0.05)and a decrease in trabecular separation(P＜0.05).In the low-and high-dose Eucommia ulmoides groups,bone trabeculae were slightly aligned and thickened,with a significant increase in bone mass.Compared with the model group,the serum level of alkaline phosphatase was reduced(P＜0.05)and the serum level of osteocalcin was elevated(P＜0.05)in the low-and high-dose Eucommia ulmoides groups.Compared with the model group,the mRNA expression of alkaline phosphatase,osteocalcin,Runx2,β-catenin,and frizzled9 were increased in the low-and high-dose Eucommia ulmoides groups(P＜0.05).Compared with the model group,the protein expression of Frizzled9 was increased in the low-dose Eucommia ulmoides group(P＜0.05),while the protein expression of β-Catenin and Frizzled9 was increased in the high-dose Eucommia ulmoides group(P＜0.05).Compared with the low-dose Eucommia ulmoides group,the high-dose Eucommia ulmoides group had a more significant improvement in the above indexes.To conclude,Eucommia ulmoides can effectively promote the alveolar bone formation,and its mechanism of action might be related to the activation of the Wnt/β-catenin signaling pathway.

BACKGROUND:Several observational studies have found a close relationship between thyroid function levels and sarcopenia,but the causal relationship between thyroid function levels and the onset of sarcopenia is not yet clear. OBJECTIVE:To investigate the causal relationship between thyroid function levels and sarcopenia using a two sample Mendelian randomization method. METHODS:A two sample Mendelian randomization analysis was conducted using genome-wide association study data on thyrotropin,free triiodothyronine,free tetraiodothyronine,subclinical hyperthyroidism,subclinical hypothyroidism,and four related phenotypes of sarcopenia-lefthand grip strength,right hand grip strength,limb lean mass,and gait speed.The inverse-variance weighted method,weighted median method,simple mode method,weighted median estimator method,and MR Egger regression method were used as analysis methods,while heterogeneity test,pleiotropy test,MR-PRESSO,leave-one-out method,funnel plot and other methods were used for sensitivity analysis. RESULTS AND CONCLUSION:Elevated levels of thyroid-stimulating hormone increased left-(β=0.02,SE=0.01,P=0.01)and right-handed grip strength(β=0.02,SE=0.01,P=0.01),an increase in free triiodothyronine decreased left-(β=-0.06,SE=0.02,P=9.5×10-5)and right-handed grip strength(β=-0.07,SE=0.02,P=9.3×10-5),and subclinical hyperthyroidism decreased gait speed(β=-4.4×10-3,SE=1.7×10-3,P=0.01).The sensitivity analysis results were basically consistent with the main analysis results.To conclude,an increase in thyroid-stimulating hormone is a protective factor for sarcopenia,and elevation of free triiodothyronine and subclinical hyperthyroidism may increase the risk of sarcopenia.

BACKGROUND:Mesenchymal stem cells can regulate the tumor microenvironment by secreting extracellular vesicles containing cytokines,growth factors and exosomes for the precise regulation of biological behavior of tumor cells. OBJECTIVE:To investigate the effects of human umbilical cord-derived mesenchymal stem cell conditioned medium and their released exosomes on the biological properties of hepatocellular carcinoma cells. METHODS:Human umbilical cord mesenchymal stem cell supernatant was collected,centrifuged and filtered at high speed to obtain human umbilical cord mesenchymal stem cell conditioned medium.Human umbilical cord mesenchymal stem cell supernatant was collected and human umbilical cord mesenchymal stem cell exosomes were extracted by ultra-high speed gradient centrifugation.Human umbilical cord mesenchymal stem cell exosomes were labeled with PKH26 and co-cultured with hepatocellular carcinoma cell MHCC97-H.The uptake of exosomes by MHCC97-H cells was observed by fluorescence microscopy.The effects of human umbilical cord mesenchymal stem cell conditioned medium and human umbilical cord mesenchymal stem cell exosomes on biological functions of hepatocellular carcinoma cells were assessed by the CCK-8 proliferation assay,Transwell migration and invasion assay,and the apoptosis assay. RESULTS AND CONCLUSION:(1)Human umbilical cord mesenchymal stem cell exosomes could be uptaken by MHCC97-H cells and was mainly distributed in the cytoplasm.(2)After treatment with human umbilical cord mesenchymal stem cell conditioned medium,MHCC97-H cells showed a significant increase in proliferation,migration,and invasion(P<0.001,P<0.05,P<0.01),and a significant decrease in apoptosis(P<0.001),while after treatment with human umbilical cord mesenchymal stem cell exosomes,MHCC97-H cells showed a decrease in proliferation(P<0.001)and migration,invasion,and apoptosis were significantly enhanced(P<0.001).(3)The results indicated that human umbilical cord mesenchymal stem cell conditioned medium had the ability to promote the proliferation,migration,invasion,and inhibit apoptosis of MHCC97-H cells,while human umbilical cord mesenchymal stem cell exosomes had the properties of promoting the migration,invasion and apoptosis of MHCC97-H cells,inhibiting the proliferation.

BACKGROUND:In the initial stage of growth plate injury inflammation,platelet-derived growth factor BB promotes the repair of growth plate injury by promoting mesenchymal progenitor cell infiltration,chondrogenesis,osteogenic response,and regulating bone remodeling. OBJECTIVE:To elucidate the action mechanism of platelet-derived growth factor BB after growth plate injury. METHODS:PubMed,VIP,WanFang,and CNKI databases were used as the literature sources.The search terms were"growth plate injury,bone bridge,platelet-derived growth factor BB,repair"in English and Chinese.Finally,66 articles were screened for this review. RESULTS AND CONCLUSION:Growth plate injury experienced early inflammation,vascular reconstruction,fibroossification,structural remodeling and other pathological processes,accompanied by the crosstalk of chondrocytes,vascular endothelial cells,stem cells,osteoblasts,osteoclasts and other cells.Platelet-derived growth factor BB,as an important factor in the early inflammatory response of injury,regulates the injury repair process by mediating a variety of cellular inflammatory responses.Targeting the inflammatory stimulation mediated by platelet-derived growth factor BB may delay the bone bridge formation process by improving the functional activities of osteoclasts,osteoblasts,and chondrocytes,so as to achieve the injury repair of growth plate.Platelet-derived growth factor BB plays an important role in angiogenesis and bone repair tissue formation at the injured site of growth plate and intrachondral bone lengthening function of uninjured growth plate.Inhibition of the coupling effect between angiogenesis initiated by platelet-derived growth factor BB and intrachondral bone formation may achieve the repair of growth plate injury.

BACKGROUND:Many recent studies have shown a close relationship between inflammatory cytokines and osteoporosis and bone mineral density(BMD).However,the causal relationship between inflammatory cytokines and BMD has not been fully revealed. OBJECTIVE:To explore the potential causal relationship between inflammatory cytokines and BMD using a two-sample Mendelian randomization analysis. METHODS:The single nucleotide polymorphisms associated with 41 circulating inflammatory cytokines were selected from the open database of genome-wide association studies(GWAS)as instrumental variables.The GWAS data about BMD were from the Genetic Factors for Osteoporosis Consortium,involving a total of 32 735 individuals of European ancestry.Inverse variance weighting was used as the primary analysis to evaluate the causal effect.Weighted median,MR Egger regression,simple mode,and weighted mode methods were used to supplement the explanation.We used the MR-Egger intercept and MR-PRESSO method to conduct a pleiotropy test,the Cochran's Q test was used to determine whether there was heterogeneity in the results,and the leave-one-out method was used to evaluate the stability of the results.In addition,to more accurately assess the causality,the Bonferroni-corrected test was used to identify inflammatory cytokines that have a strong causal relationship with BMD. RESULTS AND CONCLUSION:(1)According to the results of the inverse variance weighting method,we found a positive causal relationship between interleukin-8 and lumbar spine BMD[β=0.075,95%confidence interval(CI):0.033-0.117,P=0.000 5),while a negative causal relationship between interleukin-17 and lumbar spine BMD(β=-0.083,95%CI:-0.152 to-0.014,P=0.018).There might be a negative causal relationship between tumor necrosis factor b and femoral neck BMD(β=-0.053,95%CI:-0.088 to-0.018,P=0.003),while a positive causal relationship between basic fibroblast growth factor and femoral neck BMD(β=0.085,95%CI:0.016-0.154,P=0.015).There might be a negative causal relationship between macrophage inflammatory protein-1a and total body BMD(β=-0.056,95%CI:-0.105 to-0.007,P=0.025).There was a negative causal relationship between interleukin-5(β=-0.019,95%CI:-0.031 to-0.006,P=0.004),stromal cell-derived factor-1a(β=-0.022,95%CI:-0.038 to-0.005,P=0.010),hepatocyte growth factor(β=-0.021,95%CI:-0.041 to-0.002,P=0.030),interleukin-4(β=-0.016,95%CI:-0.032 to-0.001,P=0.034)and heel BMD,while a positive causal relationship between nerve growth factor(β=0.019,95%CI:0.002-0.036,P=0.033),granulocyte colony-stimulating factor(β=0.011,95%CI:0.000-0.022,P=0.050),and heel BMD.Meanwhile,after the Bonferroni-corrected test,there was a strong positive causal effect between interleukin-8 and lumbar spine BMD(P=0.000 5).And consistent directional effects for all analyses were observed in MR Egger,weighted median,simple mode,and weighted mode methods.(2)Sensitivity analyses revealed no heterogeneity,pleiotropy,or outliers for the causal effect of circulating inflammatory cytokines on BMD.

BACKGROUND:Pyroptosis participate in the degradation of the extracellular matrix of chondrocytes,synovial inflammation and pain,and plays an important role in the prevention and treatment of osteoarthritis.In addition,exercise can inhibit the occurrence of pyroptosis to regulate the progression of osteoarthritis,which has become a research hot spot in the prevention and treatment of osteoarthritis. OBJECTIVE:To summarize the regulatory role of pyroptosis in osteoarthritis and the mechanism of exercise-mediated pyroptosis in osteoarthritis. METHODS:PubMed and CNKI databases were searched during 1992 to 2024 with the keywords"pyroptosis,osteoarthritis,chondrocyte pyroptosis,synovial cell pyroptosis,exercise"in English and Chinese,respectively.Finally,71 relevant articles were selected according to the inclusion and exclusion criteria. RESULTS AND CONCLUSION:(1)Osteoarthritis is a chronic degenerative joint disease characterized by the breakdown of cartilage extracellular matrix,synovial inflammation,and subchondral bone remodeling.This condition often leads to organic lesions,bone pain,and functional impairment.(2)Pyroptosis,a distinct programmed cell death mechanism,involves cell lysis and the release of inflammatory cytokines,triggering a robust inflammatory response,and is closely related to the development of osteoarthritis.Pyroptosis can result in the release of numerous inflammatory factors,thereby activate the nuclear factor kappa-B transcription and increase pyroptosis protein production,and in turn exacerbate the occurrence and development of osteoarthritis.Therefore,pyroptosis can be a new direction for the prevention and treatment of osteoarthritis.(3)Exercise has been shown to down-regulate the pyroptosis protein signaling pathway and inhibit the expression of related inflammatory factors,thereby playing a pivotal role in osteoarthritis prevention and treatment.Aerobic and anaerobic exercises can delay the pathological process of osteoarthritis by inhibiting the occurrence of pyroptosis.Moderate-intensity aerobic exercise is most effective in improving osteoarthritis by inhibiting pyroptosis signaling pathways,while anaerobic exercise can have beneficial effects on osteoarthritis by improving muscle mass.

BACKGROUND:The plantarflexor weakness is a common muscle defect in patients with spastic cerebral palsy and Charcot-Marie-Tooth,which clinically manifests abnormal gaits,and the relationship between plantarflexor weakness and abnormal gaits is unclear. OBJECTIVE:To explore the biomechanical behavior of the lower limb under the action of a single factor of plantarflexor weakness to reveal the mechanism of abnormal gait induced by plantarflexor weakness and to provide guidance for the rehabilitation training of patients with plantarflexor weakness. METHODS:A predictive framework of musculoskeletal multibody dynamics in the sagittal plane was established based on OpenSim Moco to predict lower limb joint angles and muscle activation changes during walking in normal subjects.The validity of the framework was verified by combining the inverse kinematics and electromyogram activation time of the experimental data.Reduced isometric muscle forces were used to model plantarflexor weakness and to compare predicted lower extremity joint angles,joint moments,and muscle energy expenditure with normal subjects to analyze the effects of plantarflexor weakness on lower extremity biomechanics. RESULTS AND CONCLUSION:(1)The Moco-based prediction framework realistically predicted the biomechanical changes of the lower limbs during walking in normal subjects(joint angles:normalized correlation coefficient≥0.73,root mean square error≤7.10°).(2)The musculoskeletal model used a small stride support phase to increase the"heel-walking"gait during plantarflexor weakness.When the plantarflexor weakness reached 80%,the muscle energy expenditure was 5.691 4 J/kg/m,and the maximum activation levels of the gastrocnemius and soleus muscles were 0.72 and 0.53,which might cause the plantarflexor weakness patients to be more prone to fatigue when walking.(3)Muscle energy expenditure was significantly higher when the weakness of plantarflexors exceeded 40%,and the joint angles and moments of the lower limbs deteriorated significantly when the weakness of plantarflexors exceeded 60%,suggesting that there may be a"threshold"for the effect of plantarflexor weakness on gait,which may correspond to the point at which health care professionals should intervene in the clinical setting.

Objective: To evaluate the prevalence and future trend of change of the disease burden of injuries in Chinese children and adolescents from 1990 to 2021, so as to provide reference for injury prevention and control in this population. Methods: Using data from the Global Burden of Diseases, Injuries, and Risk Factors Study 2021 (GBD 2021), the trend of change in the disease burden of injuries in children and adolescents in China from 1990 to 2021 was analyzed by the Joinpoint regression model. The Bayesian age period cohort model (BAPC) was used to predict the disease burden of injuries among children and adolescents in China from 2022 to 2031. Results: From 1990 to 2021, the standardized incidence rate, standardized prevalence rate, standardized mortality rate, and standardized disability adjusted life years (DALYs) rate of injuries among children and adolescents in China showed an overall downward trend (AAPC=-1.14%, -0.76%, -5.41%, -5.03%, P <0.05). For different genders, the standardized incidence rate (7 106.00/100 000, 5 388.00/100 000), standardized mortality rate (92.00/100 000, 19.00/ 100 000 ), and standardized DALYs rate (7 834.00/100 000, 1 673.00/100 000) of injuries in boys were higher than the rate of injuries in girls in 1990 and 2021 (5 188.00/100 000, 3 874.00/100 000; 61.00/100 000, 10.00/100 000; 5 398.00/100 000, 945.00/100 000). Compared with Asia and globally, China had the fastest decline in the standardized mortality rate (AAPC= -5.41 ) and the slowest decline in the standardized prevalence rate (AAPC=-0.76) among children and adolescents. The results of the Joinpoint burden trend analysis demonstrated that the standardized incidence rate of injuries showed an increasing trend from 2005 to 2021, and the standardized prevalence rate of injuries showed an increasing trend from 2006 to 2021. Among the different age groups, the disease burden of injuries was highest in the 15-19-year-old group in 2021. For different types of injuries, the standardized incidence rate, standardized mortality rate, and standardized DALYs rate of unintentional injury were higher than those of transport injury, and self harm and interpersonal violence from 1990 to 2021. The BAPC prediction model showed that the standardized incidence rate ( 4 833.05/ 100 000-5 313.70/100 000) and standardized prevalence rate (5 433.90/100 000-5 821.88/100 000) of injury showed an increasing trend, and the standardized mortality rate (13.69/100 000-5.52/100 000) and the standardized DALYs rate ( 1 226.37/ 100 000-510.14/100 000) showed a decreasing trend during 2022-2031. The analysis of influencing factors found that children and adolescents who drank alcohol were at high risk of injury burden. Conclusions From 1990 to 2021, the injury burden of children and adolescents in China generally showed a downward trend. The standardized incidence rate and standardized prevalence rate of injuries are predicted to increase from 2022 to 2031. More targeted and individualized intervention measures should be developed to reduce the injury burden in children and adolescents.

Background Exposure to polycyclic aromatic hydrocarbons (PAHs) is associated with the development of metabolic syndrome (MS). However, the role of amino acids in PAH-induced MS remains unclear. Objective To explore the impact of PAHs exposure on the incidence of MS among coking workers, and to determine potential modifying effect of amino acid on this relationship. Methods Unmatched nested case-control design was adopted and the baseline surveys of coking workers were conducted in two plants in Taiyuan in 2017 and 2019, followed by a 4-year follow-up. The cohort comprised 667 coking workers. A total of 362 participants were included in the study, with 84 newly diagnosed cases of MS identified as the case group and 278 as the control group. Urinary levels of 11 PAH metabolites and plasma levels of 17 amino acids were measured by ultrasensitive performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Logistic regression was used to estimate the association between individual PAH metabolites and MS. Stratified by the median concentration of amino acids, Bayesian kernel machine regression (BKMR) model was employed to assess the mixed effects of PAHs on MS. Due to the skewed data distribution, all PAH metabolites and amino acids in the analysis were converted by natural logarithm ln (expressed as lnv). Results The median age of the 362 participants was 37 years, and 83.2% were male. Compared to the control group, the case group exhibited higher concentrations of urinary 2-hydroxyphenanthrene (2-OHPhe), 9-hydroxyphenanthrene (9-OHPhe), and hydroxyphenanthrene (OHPhe) (P=0.005, P=0.049, and P=0.004, respectively), as well as elevated levels of plasma branched chain amino acid (BCAA) and aromatic amino acid (AAA) (P<0.05). After being adjusted for confounding factors, for every unit increase in lnv_2-OHPhe in urine, the OR (95%CI) of MS was 1.57 (1.11, 2.26), and for every unit increase in lnv_OHPhe, the OR (95%CI) of MS was 1.82 (1.16, 2.90). Tyrosine, leucine, and AAA all presented a significant nonlinear correlation with MS. At low levels, tyrosine, leucine, and AAA did not significantly increase the risk of MS, but at high levels, they increased the risk of MS. In the low amino acid concentration group, as well as in the low BCAA and low AAA concentration groups, it was found that compared to the PAH metabolite levels at the 50th percentile (P₅₀), the log-odds of MS when the PAH metabolite levels was at the 75th percentile (P₇₅) were 0.158 (95%CI: 0.150, 0.166), 0.218 (95%CI: 0.209, 0.227), and 0.262 (95% CI: 0.241, 0.282), respectively, However, no correlation between PAHs and MS was found in the high amino acid concentration group. Conclusion Amino acids modify the effect of PAHs exposure on the incidence of MS. In individuals with low plasma amino acid levels, the risk of developing MS increases with higher concentrations of mixed PAH exposure. This effect is partly due to the low concentrations of BCAA and AAA.