Objective To analyze the atrioventricular synchronization rate after implantation of Micra AV leadless pacemaker,and the impact of postoperative programming optimization on atrioventricular synchronization rate.Methods A prospective cohort study was conducted to select patients with complete atrioventricular block who underwent Micra AV leadless pacemaker implantation at Beijing Anzhen Hospital from August 2022 to June 2023.Programming optimization were performed at 1 week,1 month,and 3 months postoperatively,and atrioventricular synchronization rate,electrical parameters,and echocardiography were recorded.Results A total of 68 patients with complete atrioventricular block implanted with Micra AV were selected,with an average age of(68.2±9.7)years,including 47 males(69.1％).All patients were successfully implanted with Micra AV,and there were no serious postoperative complications;The average threshold,sense,and impedance parameters were stable during 1 week,1 month,and 3 months after the procedure;There was no significant difference in the EF value of postoperative echocardiography(P=0.162);The average atrioventricular synchronization rates at 1 week,1 month,and 3 months postoperatively were(75.2％vs.83.8％vs.91.6％,P=0.001).Conclusions As an mechanical atrial sensing,Micra AV requires personalized adjustment of relevant parameters;Postoperative follow-up programming optimization plays an important role in the atrioventricular synchronization and comfort level in patients with complete atrioventricular block after implantation of Micra AV leadless pacemaker.

The pathogenesis of osteoarthritis (OA) is related to a variety of factors such as mechanical overload, metabolic dysfunction, aging, etc., and is a group of total joint diseases characterized by intra-articular chondrocyte apoptosis, cartilage fibrillations, synovial inflammation, and osteophyte formation. At present, the treatment methods for osteoarthritis include glucosamine, non-steroidal anti-inflammatory drugs, intra-articular injection of sodium hyaluronate, etc., which are difficult to take effect in a short period of time and require long-term treatment, so the patients struggle to adhere to doctor’s advice. Some methods can only provide temporary relief without chondrocyte protection, and some even increase the risk of cardiovascular disease and gastrointestinal disease. In the advanced stages of OA, patients often have to undergo joint replacement surgery due to pain and joint dysfunction. Mitochondrial dysfunction plays an important role in the development of OA. It is possible to improve mitochondrial biogenesis, quality control, autophagy balance, and oxidative stress levels, thereby exerting a protective effect on chondrocytes in OA. Therefore, compared to traditional treatments, improving mitochondrial function may be a potential treatment for OA. Here, we collected relevant literature on mitochondrial research in OA in recent years, summarized the potential pathogenic factors that affect the development of OA through mitochondrial pathways, and elaborated on relevant treatment methods, in order to provide new diagnostic and therapeutic ideas for the research field of osteoarthritis.

Objective To propose a Q factor-based fatigue vibration evaluation method of the ultrasonic knife tip.Methods Firstly,an ultrasonic cutter fatigue testing table was established to realize repeated cutting,which was composed of a power supply module,a three-axis moving module,an ultrasonic cutter clamping module and a control module.Secondly,10 ultrasonic knives of some brand underwent fatigue testing with the table,during which non-contact measurement of the ultrasonic knife tip vibration was carried out and the Q factors were calculated at the five periods of the fatigue test,including the periods before cutting,after 500 times of cutting,after 1 000 times of cutting,after 2 000 times of cutting and after 3 000 times of cutting.Finally,the average cutting speed and burst pressure for coagulated vessels were computed at each period to validata the effectiveness of the method proposed.Results It's indicated that Q factor could effectively reflect the fatigue degradation of the ultrasonic knife tip,while the average cutting speed and burst pressure for coagulated vessels were difficult to efficiently evaluate the fatigue degradation level of the ultrasonic knife tip due to the uncertainty factors in the measurement process.Conclusion The proposed Q factor-based evaluation method can directly evaluate fatigue vibration of the ultrasonic knife tip in an accurate and quantitative manner.[Chinese Medical Equipment Journal,2024,45(6):17-22]

Objective To apply a COMSOL-based finite element analysis method to investigating the electric field effects produced by the human lower limb musculoskeletal system under the synergistic effects of stress field and electromagnetic field.Methods Firstly,a 3D human body model was constructed by Maxon Cinema 4D R21 software,and then imported into COMSOL 6.1 software in STL format.Secondly,an electromagnetic field intervention and stress loading model for the left lower limb of the human body was designed and constructed,in which 15 Hz quasi-pulse group current signals were used for electromagnetic field excitation and the stress field was realized by applying a vibration load with an average compressive force of about 90 N/cm2 to the left foot of the human body.Finally,the electromagnetic properties of human tissue were simulated by numerical simulation,and then the effects of stress field or elecromagnetic field or combined stress field and electromagnetic field on human bioelectric field were compared.Results Simulation results showed that the electric field intensity peaked at the leg joints under both electromagnetic and stress fields acting alone or synergistically,the bioelectric field intensity generated by the human body was related to the distance from the exogenous excitation loading location,and the electric field generated under synergistic action was equivalent to the linear superposition of the bioelectric field in the tissue induced by the electromagnetic field and the stress field acting alone.Conclusion Data supplement is provided for predicting bioelectric field changes within the musculoskeletal tissue,and theoretical foundation is laid for the development and application of multi-physics field synergistic intervention therapy for treating the disorders of the lower limb musculos-keletal system.[Chinese Medical Equipment Journal,2024,45(9):21-26]

Objective To carry out accurate quantative evaluation of MRI scanning noise based on laser vibrometry technology.Methods Skull and spine MRI was performed with mute and conventional sequences.A laser vibrometry device was used to sample the surface vibration noise at the outer edge of the inspection hole of MRI system according to GB/T 16539-1996 Acoustics—Determination of sound power levels of noise sources using vibration velocity—Measurement for seal machinery,and the indicators of sound power level,sound pressure level and perceived noise level obtained by the three calculation methods(LPN1,LPN2 and LPN3)were analyzed with some dedicated MRI noise analysis software.Results The peak sound pressure levels for conventional and mute sequences of skull scanning were 81 and 63 dB(A),respectively,and mute sequence reduced the noise level significantly;the peak sound pressure levels for conventional and mute sequences of spine scanning were 79 and 75 dB(A),respectively,and the noise reduction level was significantly lower than that of skull scanning.Significant differences in noise reduction were not found in spine scanning sequences,while were found in skull scanning sequences.During spine and skull scanning LPN1,LPN2 and LPN3 obtained by the three calculation methods of conventional and mute sequences were all higher than the overall sound power and overall pressure levels obviously.Conclusion Mute sequence can not realize linear noise reduction for the whole frequency band,the perceived noise of the human ear during MRI scanning is related directly to the scanning sequence,and there may be some bias when only one physical indicator is involved in the noise evaluation of MRI system.[Chinese Medical Equipment Journal,2024,45(10):20-24]

The assessment of adverse drug events is an important basis for clinical safety evaluation and post-marketing risk control of drugs,and its causality assessment is gaining increasing attention.The existing methods for assessing the causal relationship between drugs and the occurrence of adverse reactions can be broadly classified into three categories:global introspective methods,standardized methods,and probabilistic methods.At present,there is no systematic introduction of the operational details of the various methods in the domestic literature.This paper compares representative causality assessment methods in terms of definition and concept,methodological steps,industry evaluation and advantages and disadvantages,clarifies the basic process of determining the causality of adverse drug reactions,and discusses how to further improve the adverse drug reaction monitoring and evaluation system,with a view to providing a reference for drug development and pharmacovigilance work in China.

During the progression of heart failure(HF),abnormal transduction of the transforming growth factor-β(TGF-β)/Smads signaling pathway is important mechanism of myocardial fibrosis(MF)in HF.TGF-β,a key factor in MF,is in an overexpression state in the process of MF in HF,and Smads is a major effector downstream of TGF-β.The TGF-β/Smads pathway induces abnormal proliferation of myofibroblasts,aggravates myocardial extracellular matrix deposition,and reduces the ability of the cardiac tissues to resist fibrosis,which plays a complex role in the pathogenesis of MF in HF.Traditional Chinese medicine(TCM)has the efficacy of unequivocal inhibiting myocardial collagen deposition,anti-MF,protecting the myocardium and improving cardiac function in the prevention and treatment of MF in HF and so on,and the TGF-β/Smads pathway is one of the key pathways through which TCM monomers,TCM combinations,and proprietary medicines can exert their cardioprotective effects on the HF.This paper reviews the existing experimental research results of TCM intervening in the TGF-β/Smads pathway for the treatment of MF in HF over the past 10 years,with a view to providing theoretical basis for the prevention and treatment of HF MF well as the development and of new drugs.

Objective To study the pharmacokinetic characteristics of etoricoxib tablets in healthy Chinese subjects and to evaluate the bioequivalence and safety of the test and reference formulations.Methods In a randomised,single-dose,two-period,two-sequence crossover trial,28 healthy subjects were enrolled under the fasting and fed conditions,respectively,who received a single oral dose of 60 mg of etoricoxib tablets in the test or reference formulation.The concentration of etoricoxib in plasma was detected by LC-MS/MS,and the main pharmacokinetic parameters were calculated to evaluate bioequivalence and using WinNonlin 8.2 software.Results The main pharmacokinetic parameters of the test and reference preparations were as follows:The fasting condition Cmax of etoricoxib were(1 176.96±287.95)and(1 164.93±189.65)ng·mL-1;AUC0-t were(18 651.95±6 100.27)and(19 241.39±6 107.48)ng·h·mL-1;and AUC0-∞ were(19 939.15±7 553.27)and(20 536.31±7 223.40)ng·h·mL-1.The fed condition Cmax of etoricoxib were(913.50±184.72)and(878.59±164.35)ng·mL-1;and AUC0-t were(19 085.22±5 155.01)and(18 669.54±4 508.21)ng·h·mL-1;AUC0-∞ were(20 103.77±5 567.02)and(19 528.05±4 989.74)ng·h·mL-1.The 90％confidence intervals for the geometric mean ratios of the main pharmacokinetic parameters in the fasting and fed conditions fell between 80.00％and 125.00％.The incidence of adverse events in the fasting and fed conditions were 28.57％and 21.43％,respectively.Conclusion Two kinds of etoricoxib tablets are bioequivalent,and have similar safety in healthy Chinese subjects.

Objective To evaluate the pharmacodynamics of human interferon(IFN)α1b against severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)Omicron strain in vitro.Methods Total four drugs human IFNα1b bulk,human IFNα1b eye drops,human IFNα1b spray and Remdesivir were detected for cytotoxicity by CCK-8 assay.The inhibitory effect of human IFNα1b on SARS-CoV-2 Omicron strains(BA.5/BA.2/BA.1)was determined by qPCR.Results Human IFNα1b bulk of the maximum concentration(1 × 107IU/mL)and Remdesivir of the maximum concentration(150 μmol/L)did not achieve half cytotoxicity to Vero cells;The median cytotoxicity concentrations(CC_(50))of human IFNα1b eye drops and human IFNα1b sprays were 29 958 and 37 550 IU/mL,respectively,showing toxicity to Vero cells.The median effective concentrations(EC_(50))of human IFNα1b against virus strains BA.1,BA.2 and BA.5 after incubation for 2 h in advance were 9.30,13.38 and 12.33 IU/mL and those of Remdesivir were 0.314 7,0.291 0 and0.300 3 μmol/L.When incubation with virus simultaneously,the EC_(50)of human IFNα1b to BA.1,BA.2 and BA.5 were19.68,10.91 and 18.84 IU/mL and those of the control drug Remdesivir were 0.320 5,0.274 4 and 0.304 1 μmol/L,respectively.Conclusion At the cell level in vitro,human IFNα1b of very low activity showed a good inhibitory effect on SARS-CoV-2 Omicron strain,which was expected to be a clinical specific drug for the treatment of SARS-CoV-2 Omicron strain infection.

With the development of small-molecule immunotherapy drugs, its combination with the programmed cell death ligand 1/programmed cell death protein 1 (PD-L1/PD-1) antibodies would provide a new opportunity for cancer treatment. Therefore, targeting PD-L1/PD-1 axis by small-molecule drug is an attractive approach to enhance antitumor immunity and considered as the next generation of tumor immunotherapy. In the present study, we investigated the anti-tumor role of salvianolic acid B (SAB) by regulating the PD-L1 level in tumors. Changes of total PD-L1 and membrane PD-L1 levels were determined by Western blot, flow cytometry and PD-1/PD-L1 interaction assays. The expression of mRNA level of PD-L1 was detected by real-time PCR. The cytotoxicity of activated peripheral blood mononuclear cell (PBMC) cells toward co-cultured tumor cells was measured by cell impedance assay and crystal violet experiment. Surface plasma resonance technique was used to analyze the direct interaction between SAB and ubiquitin carboxyl-terminal hydrolase 2 (USP2). The antitumor effect of SAB in vivo was examined by C57BL/6 mice bearing MC38 xenograft tumor (all animal experiments were conducted in accordance with the Animal Ethics Committee of the Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences). Western blot and flow cytometry assay showed that SAB can significantly downregulate the abundance of PD-L1 in RKO and PC3 cells in dose- and time-dependent manner. PD-1/PD-L1 binding assay revealed that SAB reduces the binding of tumor cells to recombinant PD-1 protein. Mechanism studies revealed that SAB can bind directly to USP2 protein and inhibit its activity, thus promote the ubiquitin-proteasome pathway degradation of PD-L1 proteins. In addition, Cell impedance and crystal violet staining indicated that SAB enhances the killing activity of co-cultured PBMC cells toward tumor cells. MC38 tumor transplanted mouse experiments revealed that SAB treatment displayed significant suppression in the growth of MC38 tumor xenografts in C57BL/6 mice with an inhibition rate of 63.2% at 20 mg·kg^-1. Our results demonstrate that SAB exerts its anti-tumor activity by direct binding and inhibiting the activity of USP2 and reducing the PD-L1 level. Our study provides an important material basis and scientific basis for the potential application of SAB in tumor immunotherapy drug targeting USP2-PD-L1 axis.