The biological activity of chitinase in degrading chitin has garnered extensive attention,particularly for its potential applications in biological control.This study utilized four spore-form-ing Bacillus strains isolated from Dermacentor nuttalli ticks collected in the Hulunbuir region.Traditional bacterial culture methods were employed for isolation and identification,followed by 16S rRNA sequencing and phylogenetic analysis of the purified cultures.chitin-hydrolyzing strains were screened using colloidal chitin plates,and specific chitinase genes were detected via PCR.Fer-mentation was conducted at 37.0 ℃ for 4 d,and the supernatants were subjected to enzyme activity analysis using the DNS method.Four Gram-positive Bacillus strains were successfully isolated from tick tissue samples,they were identified as B.proteolyticus,B.paramycoides,B.thuringien-sis,and B.cereus,and renamed IMH/B-1,IMH/P-1,IMH/T-1,and IMH/C-1,respectively.PCR a-nalysis detected chitinase genes in B.proteolyticus and B.thuringiensis,while B.cereus and B.pa-ramycoides lacked these genes.However,three strains B.proteolyticus,B.thuringiensis,and B.ce-reus demonstrated significant(P＜0.01)chitin degradation activity on colloidal chitin.Enzyme ac-tivity assays revealed that chitinase activity ranged from 1.292 to 2.032 U/mL,with B.proteolytic-us exhibiting the highest activity 2.032 U/mL,followed by B.cereus 1.496 U/mL and B.thuring-iensis 1.324 U/mL.This study provides a foundation for further research and application of chiti-nase-producing Bacillus strains.

The biological activity of chitinase in degrading chitin has garnered extensive attention,particularly for its potential applications in biological control.This study utilized four spore-form-ing Bacillus strains isolated from Dermacentor nuttalli ticks collected in the Hulunbuir region.Traditional bacterial culture methods were employed for isolation and identification,followed by 16S rRNA sequencing and phylogenetic analysis of the purified cultures.chitin-hydrolyzing strains were screened using colloidal chitin plates,and specific chitinase genes were detected via PCR.Fer-mentation was conducted at 37.0 ℃ for 4 d,and the supernatants were subjected to enzyme activity analysis using the DNS method.Four Gram-positive Bacillus strains were successfully isolated from tick tissue samples,they were identified as B.proteolyticus,B.paramycoides,B.thuringien-sis,and B.cereus,and renamed IMH/B-1,IMH/P-1,IMH/T-1,and IMH/C-1,respectively.PCR a-nalysis detected chitinase genes in B.proteolyticus and B.thuringiensis,while B.cereus and B.pa-ramycoides lacked these genes.However,three strains B.proteolyticus,B.thuringiensis,and B.ce-reus demonstrated significant(P＜0.01)chitin degradation activity on colloidal chitin.Enzyme ac-tivity assays revealed that chitinase activity ranged from 1.292 to 2.032 U/mL,with B.proteolytic-us exhibiting the highest activity 2.032 U/mL,followed by B.cereus 1.496 U/mL and B.thuring-iensis 1.324 U/mL.This study provides a foundation for further research and application of chiti-nase-producing Bacillus strains.

Objective This study aims to explore the efficacy of tetrahydrocurcumin(THC),the major active metabolite of curcumin,on high glucose(HG)-induced human platelet aggregation and activation as well as to clarify the underlying mechanisms in vitro.Methods Purified platelets prepared from healthy subjects were pre-incubated with various concentrations of THC(0.5 μmol/L,1 μmol/L or 10 μmol/L)or vehicle control(0.05％DMSO)for 40 min at 37℃,followed by the stimulation of normal glucose(NG,5 mmol/L)or HG(25 mmol/L)for additional 90 min.The maximal aggregation rate was determined by an aggregometer.Flow cytometry was used to measure platelet surface expression of CD62P(a typical marker of platelet activation)and generation of total intraplatelet reactive oxygen species(ROS).Meanwhile,the phosphorylation level of platelet p53 was detected by Western blot assay.Results Compared with NG group,HG intervention significantly increased platelet aggrega-tion(P<0.05)and CD62P expression(P<0.001),which were greatly inhibited by different concentrations of THC(P<0.05).Mechanistically,when compared with solvent control,THC significantly decreased the level of total ROS production(P<0.001)and p53 phosphorylation(P<0.05).In addition,HG-induced total intraplatelet ROS generation(P<0.001)and p53 phosphorylation(P<0.05)were greatly attenuated by adding a ROS scavenger N-acetyl-L-cysteine(NAC).The combination of NAC with THC(10 μmol/L)showed no additive inhibitory effects(P>0.05).Moreover,platelet aggregation and activation induced by HG were greatly decreased by NAC and a p53 specific inhibitor PFT-μ(P<0.05).The combination of THC(10 μmol/L)and NAC resulted no additive inhibitory effects on HG-increased platelet aggregation and activation(P>0.05).THC(10 μmol/L)exhibited additive inhibitory effects on platelet aggregation(P<0.05)but no additive inhibitory effects on platelet activation when combined with PFT-μ(P>0.05).Conclusions THC exerts a protective effect on HG-induced platelet aggregation and activation possibly through down-regulating ROS/p53 signaling pathway in human platelets in vitro.The current study may provide potential value for THC to improve thrombosis in diabetes mellitus and the related chronic metabolic diseases.

Objective:To investigate the risk factors and their predictive efficacy for postoperative premature epiphyseal closure in pediatric patients with distal tibial epiphyseal fractures.Methods:A retrospective cohort study was conducted to analyze the clinical data of 216 pediatric patients with distal tibial epiphyseal fractures admitted to Zhengzhou Orthopedics Hospital from January 2018 to December 2023, including 136 males and 80 females, aged 2-16 years [11.8(9.8, 13.3)years]. Among them, 112 patients were affected on the left side and 104 on the right. According to the Salter-Harris fracture classification, the fracture was classified as type I in 14 patients, type II in 97, type III in 38, type IV in 64 and type VI in 3. According to the presence of premature epiphyseal closure after surgery, the patients were divided into premature epiphyseal closure group ( n=38) and normal epiphyseal group ( n=178). Age, gender, body mass index (BMI), injury mechanism, side of injury, Salter-Harris classification of fracture, initial displacement distance of the fracture end, medial malleolar involvement by the fracture line surgical fixation method, operation duration, reduction method, and reduction quality were recorded in the two groups. Univariate analysis and binary Logistic regression analysis were used to evaluate and determine the independent risk factors for postoperative premature physeal closure in pediatric patients with distal tibial epiphyseal fracture. The receiver operating characteristic (ROC) curve was plotted and area under the curve (AUC) was calculated to evaluate the predictive efficacy of each risk factor for the occurrence of premature physeal closure in pediatric patients with distal tibial epiphyseal fractures. Results:Univariate analysis showed the occurrence of postoperative premature epiphyseal closure of the distal tibia was associated with age, Salter-Harris fracture classification, medial malleolar involvement by the fracture line, surgical fixation method, reduction method, and reduction quality ( P<0.05), while it was not correlated with gender, BMI, injury mechanism, side of injury, initial displacement distance of the fracture end, and operation duration ( P>0.05). Multivariate binary Logistic regression analysis showed that medial malleolar involvement by the fracture line ( OR=0.18, 95% CI 0.04, 0.76, P<0.05) and reduction quality ( OR=43.18,95% CI 10.71, 174.05, P<0.01) were significantly correlated with the occurrence of postoperative premature epiphyseal closure of the distal tibia. The results of ROC curve analysis showed that medial malleolar involvement by the fracture line had limited predictive efficiency (AUC=0.53, 95% CI 0.43, 0.63), reduction quality had moderate predictive efficacy (AUC=0.81, 95% CI 0.72, 0.91), while their combination demonstrated even higher predictive efficacy (AUC=0.83, 95% CI 0.74, 0.91). Conclusions:Medial malleolar involvement by the fracture line and reduction quality are independent risk factors for postoperative premature epiphyseal closure in pediatric patients with distal tibial epiphyseal fractures. Reduction quality demonstrates good predictive efficacy, while medial malleolar involvement by the fracture line shows limited predictive value. The combination of both factors achieves even better predictive performance.

Objective This study aims to explore the efficacy of tetrahydrocurcumin(THC),the major active metabolite of curcumin,on high glucose(HG)-induced human platelet aggregation and activation as well as to clarify the underlying mechanisms in vitro.Methods Purified platelets prepared from healthy subjects were pre-incubated with various concentrations of THC(0.5 μmol/L,1 μmol/L or 10 μmol/L)or vehicle control(0.05％DMSO)for 40 min at 37℃,followed by the stimulation of normal glucose(NG,5 mmol/L)or HG(25 mmol/L)for additional 90 min.The maximal aggregation rate was determined by an aggregometer.Flow cytometry was used to measure platelet surface expression of CD62P(a typical marker of platelet activation)and generation of total intraplatelet reactive oxygen species(ROS).Meanwhile,the phosphorylation level of platelet p53 was detected by Western blot assay.Results Compared with NG group,HG intervention significantly increased platelet aggrega-tion(P<0.05)and CD62P expression(P<0.001),which were greatly inhibited by different concentrations of THC(P<0.05).Mechanistically,when compared with solvent control,THC significantly decreased the level of total ROS production(P<0.001)and p53 phosphorylation(P<0.05).In addition,HG-induced total intraplatelet ROS generation(P<0.001)and p53 phosphorylation(P<0.05)were greatly attenuated by adding a ROS scavenger N-acetyl-L-cysteine(NAC).The combination of NAC with THC(10 μmol/L)showed no additive inhibitory effects(P>0.05).Moreover,platelet aggregation and activation induced by HG were greatly decreased by NAC and a p53 specific inhibitor PFT-μ(P<0.05).The combination of THC(10 μmol/L)and NAC resulted no additive inhibitory effects on HG-increased platelet aggregation and activation(P>0.05).THC(10 μmol/L)exhibited additive inhibitory effects on platelet aggregation(P<0.05)but no additive inhibitory effects on platelet activation when combined with PFT-μ(P>0.05).Conclusions THC exerts a protective effect on HG-induced platelet aggregation and activation possibly through down-regulating ROS/p53 signaling pathway in human platelets in vitro.The current study may provide potential value for THC to improve thrombosis in diabetes mellitus and the related chronic metabolic diseases.

Objective:To investigate the risk factors and their predictive efficacy for postoperative premature epiphyseal closure in pediatric patients with distal tibial epiphyseal fractures.Methods:A retrospective cohort study was conducted to analyze the clinical data of 216 pediatric patients with distal tibial epiphyseal fractures admitted to Zhengzhou Orthopedics Hospital from January 2018 to December 2023, including 136 males and 80 females, aged 2-16 years [11.8(9.8, 13.3)years]. Among them, 112 patients were affected on the left side and 104 on the right. According to the Salter-Harris fracture classification, the fracture was classified as type I in 14 patients, type II in 97, type III in 38, type IV in 64 and type VI in 3. According to the presence of premature epiphyseal closure after surgery, the patients were divided into premature epiphyseal closure group ( n=38) and normal epiphyseal group ( n=178). Age, gender, body mass index (BMI), injury mechanism, side of injury, Salter-Harris classification of fracture, initial displacement distance of the fracture end, medial malleolar involvement by the fracture line surgical fixation method, operation duration, reduction method, and reduction quality were recorded in the two groups. Univariate analysis and binary Logistic regression analysis were used to evaluate and determine the independent risk factors for postoperative premature physeal closure in pediatric patients with distal tibial epiphyseal fracture. The receiver operating characteristic (ROC) curve was plotted and area under the curve (AUC) was calculated to evaluate the predictive efficacy of each risk factor for the occurrence of premature physeal closure in pediatric patients with distal tibial epiphyseal fractures. Results:Univariate analysis showed the occurrence of postoperative premature epiphyseal closure of the distal tibia was associated with age, Salter-Harris fracture classification, medial malleolar involvement by the fracture line, surgical fixation method, reduction method, and reduction quality ( P<0.05), while it was not correlated with gender, BMI, injury mechanism, side of injury, initial displacement distance of the fracture end, and operation duration ( P>0.05). Multivariate binary Logistic regression analysis showed that medial malleolar involvement by the fracture line ( OR=0.18, 95% CI 0.04, 0.76, P<0.05) and reduction quality ( OR=43.18,95% CI 10.71, 174.05, P<0.01) were significantly correlated with the occurrence of postoperative premature epiphyseal closure of the distal tibia. The results of ROC curve analysis showed that medial malleolar involvement by the fracture line had limited predictive efficiency (AUC=0.53, 95% CI 0.43, 0.63), reduction quality had moderate predictive efficacy (AUC=0.81, 95% CI 0.72, 0.91), while their combination demonstrated even higher predictive efficacy (AUC=0.83, 95% CI 0.74, 0.91). Conclusions:Medial malleolar involvement by the fracture line and reduction quality are independent risk factors for postoperative premature epiphyseal closure in pediatric patients with distal tibial epiphyseal fractures. Reduction quality demonstrates good predictive efficacy, while medial malleolar involvement by the fracture line shows limited predictive value. The combination of both factors achieves even better predictive performance.

OBJECTIVE To establish an HPLC method for determination of the related substances in papaverine hydrochloride. METHODS NanoChrom ChromCore 120 C8 column was used; the mobile phase A consisted of 3.4 g·L−1 potassium dihydrogen phosphate aqueous solution, adjust pH to 3.5 with phosphoric acid-acetonitrile(90∶10), the mobile phase B was methanol, with gradient elution at the flow rate of 0.8 mL·min−1; the detection wavelength was 238 nm; the column temperature was 50 ℃. RESULTS The minimum separation between the main component and each impurity was >1.5; Papaverine and its thirteen impurities showed a good linear relationship in the self-concentration range(r>0.999); and the average recoveries were 93.1%−101.2% with RSDs of 2.3%−8.1%. CONCLUSION The method is accurate, sensitive and reliable, which is suitable for the determination of related substances in papaverine hydrochloride.

Objective To investigate the role of Taraxasterol(TAR)on ferroptosis in chondrocytes induced by Erastin.Methods The C28/I2 chondrocyte line was treated with Erastin to construct the ferroptosis model of chon-drocytes in vitro and the experiments were divided into Control,Erastin,TAR,and TAR+Erastin groups.Cell via-bility was detected by the CCK-8 assay.Cytotoxicity was detected by the lactate dehydrogenase(LDH)kit and the Calcein/PI cytokinesis kit.Flow cytometry was used to detect lipid reactive oxygen species(ROS).The intracellular glutathione(GSH)content was detected by GSH kit.Mitochondrial membrane potential was detected by JC-1 stai-ning and RH123 staining.ACSL4 and GPX4 protein expression and the key indicators of ferroptosis were detected by Western blot.Results TAR restored the decreased cell viability of C28/I2 chondrocytes induced by Erastin treatment as well as reduced Erastin-induced cytotoxicity(P＜0.01).Compared with the control group,the level of intracellular lipid ROS increased(P＜0.01)and the content of GSH decreased(P＜0.01)after treatment with Erastin,while TAR could reduce the production of lipid ROS(P＜0.01)and increase the content of GSH(P＜0.01).TAR restored mitochondrial membrane potential in C28/I2 chondrocytes ferroptosis,decreased ACSL4 pro-tein expression(P＜0.01)and increased GPX4 protein expression(P＜0.01).In addition,TAR restored the re-duced cell viability caused by IL-1 β treatment.Conclusion TAR can inhibit Erastin induced ferroptosis in C28/I2 chondrocytes,which may be related to the regulation of ACSL4 and GPX4 protein expression.

Objective To investigate the protective effects of Sulforaphane(SFN)against high glucose(HG)-induced human platelet apoptosis and elucidate the underlying mechanisms in vitro.Methods Purified platelets obtained from healthy individuals were pre-incubated with various concentrations of SFN(5,10,or 20 μmol/L)or a vehicle control(0.05%DMSO)for 40 minutes at 37℃.Subsequently,the platelets were stimulated with normal glucose(NG,5 mmol/L)or high glucose(HG,25 mmol/L)for an additional duration of 90 minutes.Flow cytometry was employed to assess platelet mitochondrial membrane potential depolarization(Δψm),exposure of phosphatidylserine(PS),and generation of total intraplatelet reactive oxygen species(ROS).Phosphorylation levels of PI3K and Akt were determined using Western blot.Results Compared to NG-treated human platelets,HG significantly induced depolarization of platelet Δψm and exposure of PS(P＜0.001).These effects of HG were markedly attenuated by various concentrations of SFN(P＜0.001).Mechanistically,SFN down-regulated the phosphorylation levels of PI3K(P＜0.01)and Akt(P＜0.05),which were increased by HG when compared to the vehicle control,and substantially reduced total intracellular ROS levels(P＜0.001).The inhibitory effects of SFN on HG-induced phosphorylation of PI3K and Akt,as well as its efficacy on total intracellular ROS generation,Δψm depolarization,and PS exposure in HG-stimulated human platelets were completely reversed by a specific agonist for PI3K,740 Y-P.Conclusions The current study demonstrates that SFN exerts a protective effect on platelet apoptosis induced by HG,potentially through the down-regulation of the PI3K/Akt-mediated pathway in human platelets in vitro.These findings suggest that SFN may hold promise for improving thrombosis in diabetes mellitus and related chronic metabolic diseases.

Objective To investigate the role and possible mechanism of curcumin(Cur)regulating Peroxiredoxin-6(Prdx6)expression in inhibiting Erastin-induced ferroptosis in C28/I2 chondrocytes.Methods Safranin O/Fast Green and hematoxylin-eosin(HE)staining were performed to observe the pathological changes in the knee joint of rats with osteoarthritis(OA).The expression levels of Prdx6 and GPX4 proteins in cartilage tissues with OA were detected by immunohistochemistry and Western blot.C28/I2 chondrocytes were treated with different concentrations of Cur,cell viability was detected by thiazolyl blue tetrazolium bromide(MTT)assay and cytotoxicity was measured by lactic dehydrogenase(LDH)assay.The production of lipid reactive oxygen species(ROS)in chondrocytes was detected by flow cytometry,and the total glutathione(GSH)assay kit was used to detect the GSH level in chondro-cytes.Western blot was performed to detect the expression level of Prdx6 and ferroptosis-related proteins in chon-drocytes.The interaction between the Cur molecule and Prdx6 was analyzed through the molecular docking tech-nique.Results During the OA progression,OA rats and OA patients showed pathological changes such as damage to the cartilage and a decrease in the number of chondrocytes.The expression levels of Prdx6 and GPX4 were re-duced in the cartilage tissues of OA patients compared with healthy people.Further study revealed that the treat-ment of Erastin-induced ferroptosis in C28/I2 chondrocytes in a mouse model with 20 μmol/L of Cur could improve cell viability,decrease cytotoxicity,inhibit lipid ROS production,and increase the level of intracellular GSH.Western blot results showed decreased expression of Prdx6,SLC7A11,FTH,and GPX4 and increased expression of ACSL4.In addition,Cur molecules interacted with Prdx6 protein by van der Waals forces and π bond.Conclu-sion Cur may inhibit Erastin-induced ferroptosis in C28/I2 chondrocytes by upregulating the Prdx6 expression lev-el.