Objective To investigate the compressive relaxation behavior of cartilage in different regions of the knee joint at different strain rates,and construct the viscoelastic mechanics of cartilage in each region,so as to provide a reference for the prevention of cartilage-related diseases and the development of cartilage repair materials.Methods The knee cartilage of beagle dogs was regionally divided,and the uniaxial unconfined compressive relaxation properties of cartilage in each region were tested by a universal testing machine at different strain rates,and the constitutive models were constructed.Results The cartilage exhibited a notable stress attenuation.Furthermore,the normalized stress reduction increased significantly with increasing strain rate.For cartilage in lateral plateaus of tibia,the normalized stress reduction at strain rate 5×10-4 s-1 was 19%,and increased to 69%at strain rate 5×10-2 s-1.The relaxation equilibrium stress remained relatively constant at all strain rates.The Ogden-Prony viscoelastic model of cartilage in each region was developed with a goodness of fit R2>0.98.Conclusions The knee cartilage demonstrates a significant viscoelastic response in relaxation tests,exhibiting the rate-dependent and region-dependent properties.The Ogden-Pony viscoelastic model can reflect the strain rate-dependent stress relaxation behavior of cartilage.

Objective To investigate the coagulation effect of a cold atmospheric plasma(CAP)jet device with helium as the working gas and to study its coagulation mechanism preliminarily.Methods A CAP jet device treatment group,a helium airflow treatment group,a hot air treatment group(60℃)and a natural coagulation group were formed according to the treatment modes of the blood samples,with 10 μL of blood samples involved in each group,in order to validate the coagulation effect of the CAP jet device in vitro;the coagulation mechanism of the CAP jet device was explored by its application to the treatment of anticoagulated whole blood,platelet-rich plasma and platelet-depleted plasma;the coagulation effect of the CAP jet device in vivo was verified with a mouse liver punctate hemorrhage model and a rabbit mesenteric hemorrhage model.Results The CAP jet device can significantly accelerate the coagulation of anticoagulated blood droplets,and the coagulation time of anticoagulated blood droplets in the CAP jet device-treated group was shortened from 28 min in the natural coagulation group to(23±1.56)s,with the difference statistically significant(P<0.05),and the CAP jet device treatment group gained advantages significantly over the helium airflow treatment group(P<0.05)and the hot air(60℃)treatment group(P<0.05)in coagulation-promoting effect;the procoagulant effect of the CAP jet device rose with the increase of platelet content in blood droplets,and the coagulation effect of platelet-rich blood droplets was significantly better than that of whole blood(P<0.05),while no coagulation was observed in platelet-poor droplets.The CAP jet device could rapidly stop hemostasis of punctate hemorrhage in mouse liver and mesenteric hemorrhage in rabbits without delayed hemorrhage occurring within 10 min,and no obvious structural abnormality of the liver and thermal damage of the tissue were found microscopically.Conclusion The CAP jet device plays procoagulant and hemostatic effects in vivo and in vitro,and its effect is not dependent on temperature and airflow evaporation effects and is considered to be related to platelet activation,with low thermal damage to living tissue.[Chinese Medical Equipment Journal,2025,46(6):20-27]

Objective:To explore the protective mechanism of dexmedetomidine (Dex) in a model of broncho-pulmonary dysplasia (BPD) in mice exposed to hyperoxia.Methods:Neonatal rats were randomly assigned to four groups:air control group,hyperoxia injury group,Dex control group,and hyperoxia+Dex group,with six animals in each group.The air control and Dex control groups were exposed to ambient air,while the hyperoxia injury and hyperoxia+Dex groups were exposed to 90% O 2.The Dex control and hyperoxia+Dex groups received daily intraperitoneal injections of Dex at a dosage of 500 μg/kg.Lung tissue samples were collected after 7 days.Histomorphological changes in lung tissue were evaluated using hematoxylin and eosin (HE) staining,and mitochondrial ultrastructural changes in type I epithelial cells of neonatal rat lung tissue were observed via transmission electron microscopy.The activity of Complex Ⅰ in neonatal rat lung tissue was assessed.The expression levels of PINK1 and Parkin in neonatal rat lung tissue were measured using quantitative PCR (qPCR).Western blot analysis was conducted to determine the protein expression levels of PINK1 and Parkin in lung tissues. Results:Under transmission electron microscopy,mitochondrial structures were intact in the lung tissues of both the air control group and the Dex control group.However,significant mitochondrial damage was observed in the hyperoxia injury group,while the hyperoxia+Dex group exhibited some relief from mitochondrial damage compared to the hyperoxia injury group.The activity of the oxidized respiratory chain Complex Ⅰ in the hyperoxia injury group was significantly lower than that in the air control group (4.824±0.804 vs.15.276±0.804, P<0.05) and the hyperoxia+Dex group(4.824±0.804 vs.9.648±0.804, P<0.05).After qPCR analysis,the expression levels of PINK1 and Parkin in the hyperoxia injury group were higher than those in the air control group(1.80±0.06 vs.1.00±0.07,2.10±0.14 vs.1.00±0.09, P<0.05),but lower than those in the hyperoxia+Dex group(1.80±0.06 vs.3.61±0.19,2.10±0.10 vs.4.24±0.43, P<0.05).Western blot analysis revealed that the expression levels of PINK1 and Parkin in the hyperoxia injury group were higher than those in the air control group(2.16±0.11 vs.1.00±0.01,3.82±0.13 vs.1.00±0.01, P<0.05),but lower than those in the hyperoxia+Dex group(2.16±0.11 vs.3.35±0.14,3.82±0.13 vs.5.48±0.15, P<0.05).There were no significant differences in mitochondrial structure integrity,Complex Ⅰ enzyme activity,or the expression levels of PINK1 and Parkin,as assessed by qPCR and Western blot analysis,between the air control and Dex control groups( P>0.05). Conclusion:Dex effectively mitigates mitochondrial ultrastructural damage in BPD model mice,enhances the activity of Complex Ⅰ in the oxidative respiratory chain,reduces mitochondrial damage,and increases the activation of the PINK1-Parkin-mediated mitophagy pathway,thereby promoting lung protection.

Purpose To quantitatively compare the diffusion parameters of mono-and biexponential diffusion-weighted imaging models,and to obtain optimal sets of b-values in diffusion-weighted MRI for obtaining monoexponential apparent diffusion coefficient(ADC)close to perfusion-insensitive intravoxel incoherent motion(IVIM)model ADC(ADCIVIM)in identifying of pulmonary solid benign and malignant lesions.Materials and Methods IVIM was performed in 40 patients with solid nodule and masse in Xi'an Gaoxin Hospital from July 2021 to August 2022 using a 3.0T MR imager.Two experienced diagnostic radiologists subjectively evaluated the IVIM images.A single index model was used to calculate ADC values(ADC0-1 000,ADC20-1 000,ADC50-1 000,ADC80-1 000,ADC150-1 000,ADC300-1 000,ADC500-1 000,ADC300,500,1 000,ADC300,800,1 000,ADC300,500,ADC300,800 and ADC300,1 000).The reference standard ADCIVIM value were calculated using a double-exponential model.The physician's measurements between two physicians were measured.The malignant and benign groups were compared and receiver operator characteristic curve for all parameters were analyzed.Results The measurement consistency of ADC values under b value sets and ADCIVIM was very good,and the intraclass correlation coefficient was more significant than 0.75.The differences between ADCIVIM and ADC values in each b group were statistically significant(t=-6.016--2.500,all P<0.05).The area under the curve(AUC)of ADCIVIM was the largest(0.906),with an optimal threshold of 1.271×10-3 mm2/s,a sensitivity of 80.0%and a specificity of 93.0%.The diagnostic efficacy close to ADCIVIM were ADC300,800(AUC=0.891),ADC50-1 000(AUC=0.827)and ADC300,800,1 000(AUC=0.795),respectively.The optimal threshold of ADC300,800 was 1.140×10-3 mm2/s,the sensitivity and specificity were 80.0%and 93.7%,respectively.Conclusion Combining b-values 300 s/mm2 and 800 s/mm2 is recommended as routine scanning parameters for identifying the insensitive monoexponential ADC between benign and malignant solid pulmonary lesions.

Objective To investigate the coagulation effect of a cold atmospheric plasma(CAP)jet device with helium as the working gas and to study its coagulation mechanism preliminarily.Methods A CAP jet device treatment group,a helium airflow treatment group,a hot air treatment group(60℃)and a natural coagulation group were formed according to the treatment modes of the blood samples,with 10 μL of blood samples involved in each group,in order to validate the coagulation effect of the CAP jet device in vitro;the coagulation mechanism of the CAP jet device was explored by its application to the treatment of anticoagulated whole blood,platelet-rich plasma and platelet-depleted plasma;the coagulation effect of the CAP jet device in vivo was verified with a mouse liver punctate hemorrhage model and a rabbit mesenteric hemorrhage model.Results The CAP jet device can significantly accelerate the coagulation of anticoagulated blood droplets,and the coagulation time of anticoagulated blood droplets in the CAP jet device-treated group was shortened from 28 min in the natural coagulation group to(23±1.56)s,with the difference statistically significant(P<0.05),and the CAP jet device treatment group gained advantages significantly over the helium airflow treatment group(P<0.05)and the hot air(60℃)treatment group(P<0.05)in coagulation-promoting effect;the procoagulant effect of the CAP jet device rose with the increase of platelet content in blood droplets,and the coagulation effect of platelet-rich blood droplets was significantly better than that of whole blood(P<0.05),while no coagulation was observed in platelet-poor droplets.The CAP jet device could rapidly stop hemostasis of punctate hemorrhage in mouse liver and mesenteric hemorrhage in rabbits without delayed hemorrhage occurring within 10 min,and no obvious structural abnormality of the liver and thermal damage of the tissue were found microscopically.Conclusion The CAP jet device plays procoagulant and hemostatic effects in vivo and in vitro,and its effect is not dependent on temperature and airflow evaporation effects and is considered to be related to platelet activation,with low thermal damage to living tissue.[Chinese Medical Equipment Journal,2025,46(6):20-27]

Objective:To explore the therapeutic efficacy and prognostic factors of combined rituximab and intensive chemotherapy for sporadic adult Burkitt lymphoma (BL) .Methods:This retrospective study examined the clinical and survival data of 30 patients newly diagnosed with BL between July 2011 and February 2023 at the Blood Diseases Hospital. Kaplan-Meier method was used for survival analysis, and the log-rank test was used for univariate analysis of prognostic factors.Results:The median age of the 30 patients was 43 years (24 - 66 years), and the male to female ratio was 3: 2. Extranodal invasion was present in 80% of the patients, with involvement of the bone marrow in 53.3% and central nervous system in 10.0%. The Ann Arbor stage was Ⅲ and Ⅳ in 86.7%. According to the number of Burkitt Lymphoma International Prognostic Index (BL-IPI) risk factors, patients were classified as low risk (0) in 20.0%, intermediate risk (1) in 43.3%, and high risk (≥2) in 36.7%. All patients were treated with an induction regimen of rituximab combined with intensive chemotherapy, with objective and complete response rates of 80.0% and 76.7%, respectively. The median follow-up was 49 months (6-153 months), and the 5-year progression-free survival (PFS) and overall survival (OS) rates were both (76.7±7.7) %. All patients with limited stage ( n=4) achieved continuous complete remission (CCR). Patients who had high risk, advanced stage sensitive to induction therapy ( n=10) sequentially received first-line autologous hematopoietic stem cell transplantation (auto-HSCT) as consolidation therapy; 9 patients achieved CCR, whereas 1 patient with central nervous system invasion developed early disease progression and died. The BL-IPI low, intermediate, and high risk groups had respective 5-year PFS rates of (83.3±15.2) %, 100.0%, and (45.5±15.0) % ( P=0.0069) and OS rates of (83.3±15.2) %, 100.0%, and (45.5±15.0) % ( P=0.0075). The main adverse effects of induction therapy were myelosuppression and secondary infections, which were effectively managed by appropriate symptomatic treatment. Univariate analysis demonstrated that worse PFS was associated with BL-IPI score ≥2 ( HR=4.90, 95% CI 1.02-23.45, P=0.0329) ; extranodal invasion at ≥2 sites ( HR=12.62, 95% CI 2.59-61.62, P=0.0021) ; and failure to achieve first complete response (CR1) after induction therapy ( HR=31.86, 95% CI 4.19-242.20, P<0.0001) . Conclusions:Intensive immunochemotherapy regimens were effective and well-tolerated by adult patients with highly aggressive BL. Treatment efficacy was ideal in patients with limited-stage disease, whereas prognosis was unsatisfactory in patients with high-risk BL-IPI. Sequential first-line auto-HSCT consolidation therapy may further improve outcomes in patients with high-risk advanced-stage disease who are sensitive to induction therapy. BL-IPI score ≥2, extranodal invasion at ≥2 sites, and failure to achieve CR1 after induction therapy were adverse prognostic factors in adult patients with BL.

Objective:To explore the safety and efficacy of intraosseous regional administration (IORA) of vancomycin for preventing infection in primary total knee arthroplasty (TKA).Methods:A total of 124 patients with knee osteoarthritis undergoing TKA between February 2024 and May 2024 at nine hospitals were enrolled. Preoperative infection prophylaxis involved either IORA (0.5 g vancomycin administered via intraosseous regional infusion before incision) or intravenous infusion (1 g vancomycin via peripheral vein). The IORA group included 15 males and 47 females with a median age of 66.5 years (range, 60.0-70.0 years), while the intravenous group included 14 males and 48 females with a median age of 66.0 years (range, 61.8-70.3 years) years. Intraoperative samples were collected including fat and synovium tissues after incision, before prosthesis placement, and after tourniquet release; distal femoral cancellous bone during femoral osteotomy; proximal tibial cancellous bone during tibial osteotomy; proximal intercondylar cancellous bone before prosthesis placement; and peripheral blood from non-infused arms at surgery initiation and after tourniquet release. Vancomycin concentrations were measured using liquid chromatography-tandem mass spectrometry. Vital sign changes were recorded from admission to 5~10 minutes post-IORA (IORA group) or post-incision (intravenous group). Follow-ups were conducted on postoperative day 1 and 3, and at 1 and 3 months, to document complications including IORA-related adverse events, periprosthetic joint infections, surgical site infections, red man syndrome, acute kidney injury, deep vein thrombosis and so on.Results:Vancomycin concentrations in bone, fat, and synovial tissue samples were significantly higher in the IORA group than in the intravenous group ( P<0.05), while vancomycin concentrations in blood samples were significantly lower in the IORA group than in the intravenous group ( P<0.05). Only 7.3%(41/558) of tissue samples in the IORA group had vancomycin concentrations below 2.0 μg/g (the minimum inhibitory concentration of vancomycin against coagulase-negative staphylococcus), compared to 59.3%(331/558) in the intravenous group (χ 2=11.285, P<0.001). In the intravenous group, 16.9%(21/124) of blood samples had vancomycin concentrations exceeding 15.0 mg/L (the threshold associated with a significantly increased risk of nephrotoxicity), while all concentrations in the IORA group were below this threshold, the difference was statistically significant (χ 2=22.943, P<0.001). There were no statistically significant difference ( P>0.05) in vital signs changes before and after vancomycin administration between the two groups. Two patients in the intravenous group experienced incision exudate, while no other related complications occurred in either group. Conclusions:Compared to the traditional intravenous infusion of 1 g vancomycin, intraosseous injection of a low dose (0.5 g) of vancomycin achieves higher local tissue concentrations in the knee joint with a lower incidence of adverse reactions and is safe for infection prophylaxis. Despite guidelines not recommending the routine use of vancomycin for preventing infection after primary TKA, intraosseous injection of 0.5 g vancomycin may be considered intraoperatively for primary TKA in the following scenarios: patients in medical institutions with a high prevalence of methicillin-resistant staphylococcus aureus (MRSA) infections, patients with potential preoperative MRSA colonization, or patients with cephalosporin allergy.

Objective To explore the construction of α-1,3-galactosyltransferase (GGTA1) gene-knockout (GTKO) Diannan miniature pigs and the kidney xenotransplantation from pigs to rhesus macaques, and to assess the effectiveness of GTKO pigs. Methods The GTKO Diannan miniature pigs were constructed using the CRISPR/Cas9 gene-editing system and somatic cell cloning technology. The phenotype of GTKO pigs was verified through polymerase chain reaction, Sanger sequencing and immunofluorescence staining. Flow cytometry was used to detect antigen-antibody (IgM) binding and complement-dependent cytotoxicity. Kidney xenotransplantation was performed from GTKO pigs to rhesus macaques. The humoral immunity, cellular immunity, coagulation and physiological indicators of the recipient monkeys were monitored. The function and pathological changes of the transplanted kidneys were analyzed using ultrasonography, hematoxylin-eosin staining, immunohistochemical staining and immunofluorescence staining. Results Single-guide RNA (sgRNA) targeting exon 4 of the GGTA1 gene in Diannan miniature pigs was designed. The pGL3-GGTA1-sgRNA1-GFP vector was transfected into fetal fibroblasts of Diannan miniature pigs. After puromycin selection, two cell clones, C59# and C89#, were identified as GGTA1 gene-knockout clones. These clones were expanded to form cell lines, which were used as donor cells for somatic cell nuclear transfer. The reconstructed embryos were transferred into the oviducts of trihybrid surrogate sows, resulting in 13 fetal pigs. Among them, fetuses F04 and F11 exhibited biallelic mutations in the GGTA1 gene, and F04 had a normal karyotype. Using this GTKO fetal pig for recloning and transferring the reconstructed embryos into the oviducts of trihybrid surrogate sows, seven surviving piglets were obtained, all of which did not express α-Gal epitope. The binding of IgM from the serum of rhesus monkey 20# to GTKO pig PBMC was reduced, and the survival rate of GTKO pig PBMC in the complement-dependent cytotoxicity assay was higher than that of wild-type pig. GTKO pig kidneys were harvested and perfused until completely white. After the left kidney of the recipient monkey was removed, the pig kidney was heterotopically transplanted. Following vascular anastomosis and blood flow restoration, the pig kidney rapidly turned pink without hyperacute rejection (HAR). Urine appeared in the ureter 6 minutes later, indicating successful kidney transplantation. The right kidney of the recipient was then removed. Seven days after transplantation, the transplanted kidney had good blood flow, the recipient monkey's serum creatinine level was stable, and serum potassium and cystatin C levels were effectively controlled, although they increased 10 days after transplantation. Seven days after transplantation, the levels of white blood cells, lymphocytes, monocytes and eosinophils in the recipient monkey increased, while platelet count and fibrinogen levels decreased. The activated partial thromboplastin time, thrombin time and prothrombin time remained relatively stable but later showed an upward trend. The recipient monkey survived for 10 days. At autopsy, the transplanted kidney was found to be congested, swollen and necrotic, with a small amount of IgG deposition in the renal tissue, and a large amount of IgM, complement C3c and C4d deposition, as well as CD68⁺ macrophage infiltration. Conclusions The kidneys of GTKO Diannan miniature pigs may maintain normal renal function for a certain period in rhesus macaques and effectively overcome HAR, confirming the effectiveness of GTKO pigs for xenotransplantation.

Objective: To explore the clinical characteristics, diagnosis, and treatment of ectopic thyroid gland in the parotid gland area, and to provide clinical ideas for the diagnosis and treatment of ectopic thyroid gland. Methods: A case of a normal thyroid gland with ectopic thyroid gland tissue in the parotid gland area in the neck was reported. The male patient was 20 years old. The chief complaint was the discovery of a painless mass gradually increasing under the left earlobe for one month. Clinical examination showed obvious bulging of the tissue under the left earlobe. A strip-shaped mass approximately 3.0 cm long could be palpated. It was soft in texture, with a clear boundary, and located under the skin. The skin was pale red and of normal temperature. The body position movement test was negative. Color Doppler ultrasound of the thyroid gland in the neck showed that the shape and size of the thyroid gland were normal. CT images of the head and neck showed a band-like soft tissue density shadow at the area of the parotid gland behind and below the left earlobe, with a clear boundary. The CT value was approximately 30 HU, and further enhancement yielded no additional findings. The admitting diagnosis was a mass in the left parotid gland area. The tumor was incised using a conventional surgical method for the parotid gland area. During the operation, it was found that the tumor was located under the skin, and the contents were bright-red granulomatous tissue without a capsule and adhesive to the skin tissue. The parotid gland capsule was not involved. After the tumor was completely scraped off, intermittent suturing was performed. The resected tumor was sent for pathological examination. A retrospective analysis of the diagnosis and treatment of this type of case was conducted in combination with a literature review. Results: The wound of the patient failed to heal in the first stage after the operation. By applying iodoform gauze for pressurized dressing changed weekly, the wound gradually healed about 2 months later. The postoperative pathological report showed an ectopic thyroid gland in the left parotid gland area. The results of the literature review indicate that ectopic thyroid glands can be partial or complete. In the former, normal thyroid gland tissue exists in the neck, and some thyroid gland tissue appears in other locations, mostly at the base of the tongue and mediastinum. In the latter, the thyroid gland in the neck is absent. Both can present with abnormal thyroid gland function and local compression symptoms, and the symptoms are more obvious in patients with a complete ectopic thyroid gland. Ectopic thyroid glands are mainly diagnosed and differentiated through physical examination and imaging examination. Ectopic thyroid glands occurring subcutaneously in the parotid gland area are extremely rare. Physicians should design personalized treatment plans based on clinical examinations and surgical indications. Conclusion A subcutaneous ectopic thyroid gland in the parotid gland area is rare. For ectopic thyroid gland surgery, a reasonable surgical plan should be designed considering the patient's aesthetic needs and prognosis. Puncture biopsy should be performed when necessary to formulate the surgical plan.

Objective To develop GTKO (α-1,3-galactosyltransferase gene-knockout, GTKO)/hCD55 (human CD55) gene-edited xenotransplant donor pigs and verify their function. Methods In this study, CRISPR (clustered regularly interspaced short palindromic repeats)/Cas9 (CRISPR-associated nuclease 9), PiggyBac transposon technology and somatic cell nuclear transfer technology were used to construct GTKO/hCD55 gene-edited Diannan miniature pigs. The phenotype and function of GTKO/hCD55 pigs were analyzed by Sanger sequencing, real-time fluorescence quantitative PCR, flow cytometry, immunofluorescence, bisulfite sequencing, antigen-antibody binding assays, and complement-dependent cytotoxicity assays. Results After transfection of PX458 and PiggyBac gene editing vectors into wild-type fetal pig fibroblasts, 48 single-cell colonies were obtained through puromycin drug screening. Two single-cell colonies were selected for somatic cell nuclear transfer, resulting in two fetal pigs at 33 days of gestation. The GGTA1(α-1,3-galactosyltransferase) genotypes of fetal pig F01 were -17 bp and wild type (WT), while the GGTA1 genotypes of fetal pig F02 were -26 bp/+2 bp and -3 bp. The hCD55 mRNA expression levels of both fetal pigs were significantly higher than those of WT pigs (P＜0.01). The fetal pig F02 was selected as the donor cell source for recloning, 11 surviving piglets were obtained, all identified as GTKO/hCD55 gene-edited pigs. These pigs showed absence of α-Gal antigen expression, but weak or no expression of hCD55 was observed. Methylation analysis of the hCD55 gene's CpG island showed hypermethylation in kidney tissue lacking hCD55 expression, whereas it was not methylated or partially methylated in kidney tissue expressing hCD55. Moreover, codon optimization of the CpG island of the hCD55 gene to reduce CG content could achieve stable expression of the hCD55 gene. In addition, antigen-antibody binding experiment showed that the amount of human IgM binding to GTKO/hCD55 gene-edited pig fibroblasts was significantly lower than that of WT pigs (P＜0.01). Complement-dependent cytotoxicity experiment showed that the survival rate of fibroblasts in GTKO/hCD55 pigs was significantly higher than that in WT pigs (P＜0.01). Conclusion This study demonstrates the successful generation of GTKO/hCD55 gene-edited xenotransplant donor pigs. Methylation-induced gene silencing of the hCD55 gene can be effectively avoided by reducing the CG content of the CpG island through codon optimization. This study provides a reference for the development of xenotransplant donor pigs and guides subsequent research on xenotransplantation.