Objective To develop an ion-pairing reversed-phase high performance liquid chromatography(IP-RP-HPLC)method for the determination of L-methionine sulphoximine(MSX) residues in recombinant protein therapeutics, and to verify and preliminarily apply it, so as to provide a reference for the quality control of related products.Methods A chromatographic analysis method was screened and the mobile phase conditions such as ion-pairing reagent, pH and salt concentration were optimized to develop an IP-RP-HPLC method for the determination of MSX residues in recombinant protein therapeutics. The method was verified for specificity, system applicability, linearity, limit of detection(LOD) and limit of quantitation(LOQ), precision, accuracy and solution stability, by which the residual MSX contents in multiple batches of in-process sample and bulk of recombinant protein therapeutics were determined.Results The chromatographic conditions were determined as follows: using Hypersil GOLDTMC18 column(4. 6 mm × 250 mm, 5 μm) at column temperature of 25 ℃; 50 mmol/L sodium dihydrogen phosphate(containing 5 mmol/L sodium 1-octane sulfonate, pH 2. 0)-acetonitrile(volume fraction of 85 ∶ 15) as mobile phase for isocratic elution at a flow rate of 0. 6 mL/min; detection wavelength of 200 nm; injection volume of 50 μL. The method exhibited good specificity and system applicability. The control substance showed good linearity in the concentration range of 10-100 μg/mL, with a correlation coefficient(R) of 0. 999 95. The LOD and LOQ were 5 and 0. 5 μg/mL, respectively. MSX was not detected in either recombinant protein A or B, and the relative standard deviations(RSDs) of the measured concentrations of six parallel spiked samples were 1. 3% and 1. 1%, respectively, with the recovery rates ranged from 94% to 103%. For recombinant protein A spiked test sample placed at 10 ℃, the RSD of the measured concentrations at 0 h and 12 h were 2. 1%. MSX was not detected in the in-process samples and bulk of recombinant protein A test samples and three batches of recombinant protein B samples.Conclusion The developed IP-RP-HPLC method has the characteristics of simple operation and high sensitivity, and can be used for the quality control of MSX residues in recombinant protein therapeutics.

Objective To investigate the predictive value of the combined tumor burden score (TBS) and platelet-albumin-bilirubin (PALBI) score model for postoperative tumor recurrence in liver transplant recipients with hepatocellular carcinoma (HCC). Methods The general information of 158 recipients diagnosed with HCC and underwent liver transplantation at the 900th Hospital of the Joint Logistics Support Force of the Chinese People's Liberation Army from 2008 to 2021 was collected. Lasso regression analysis combined with multivariate Cox regression analysis were used to identify independent risk factors for postoperative tumor recurrence after liver transplantation with HCC. A nomogram prediction model was constructed based on variables selected by Lasso regression analysis, and the predictive performance of the model was verified by calibration curve and clinical decision curve. The optimal cut-off values for postoperative tumor recurrence in liver transplant recipients with HCC were determined by receiver operating characteristic (ROC) curve, and Kaplan-Meier analysis was used to compare survival differences among different groups. Results Among the 158 liver transplant recipients with HCC, 82 experienced tumor recurrence, with a recurrence rate of 51.9% and a median tumor-free survival time of 10 (4, 25) months. Results of Lasso regression analysis and multivariate Cox regression analysis showed that alpha-fetoprotein (AFP) ≥400 ng/mL, TBS and PALBI score were all independent risk factors for postoperative tumor recurrence in liver transplant recipients with HCC (all P<0.05). The combined high TBS-high PALBI score showed the highest predictive value (hazard ratio 6.909, 95% confidence interval 3.067-15.563, P<0.001). A nomogram prediction model was constructed based on six variables selected by Lasso regression analysis. Calibration curve showed good consistency between the model's predicted results and the ideal curve. Decision curve analysis indicated that the nomogram prediction model provided the highest clinical benefit for predicting 1-year tumor-free survival after liver transplantation with HCC. Time-dependent ROC curves at 1, 3 and 5 years after surgery showed that TBS-PALBI model had good predictive performance, with no significant difference in area under the curve (AUC) compared with TBS-PALBI-AFP model. The optimal cut-off values for predicting postoperative tumor recurrence were determined by ROC curve, with a PALBI score cut-off of −2.334 and a TBS cut-off of 5.305. Recipients were divided into a low TBS-low PALBI score group (n=47) and a low/high TBS-low/high PALBI score group (at least one score was high) (n=111). Kaplan-Meier survival analysis showed that the low TBS-low PALBI score group had a higher tumor-free survival rate than the low/high TBS-low/high PALBI score group, with a significant difference (P<0.05). Conclusions TBS-PALBI model provides a novel, simple and effective tool for assessing the prognosis of liver transplant recipients with HCC. The nomogram model constructed based on this has significant advantages in predictive performance and may serve as a reference for guiding individualized treatment plans and improving clinical outcomes.

ObjectiveBased on tumor necrosis factor alpha （TNF-α）/tumor necrosis factor receptor 1 （TNFR1）/receptor-interacting protein kinases （RIPKs） signaling pathway， this paper aims to study the effect of modified Erchentang on inflammation in rats with chronic obstructive pulmonary disease （COPD） and explore its mechanism of action. MethodA total of 60 SD rats were randomly divided into normal group， model group， high， medium， and low-dose groups （20， 10， 5 g·kg^-1·d^-1） of modified Erchentang， and Xiaokechuan group （3.5 mL·kg^-1·d^-1）， with 10 rats in each group. The COPD rat model was established by cigarette smoke combined with lipopolysaccharide （LPS）. The normal group and model group were given the same amount of normal saline for 21 days by gavage administration. The contents of TNF-α and TNFR1 in bronchoalveolar lavage fluid （BALF） of rats were detected by enzyme-linked immunosorbent assay （ELISA）. Real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） was used to detect mRNA expressions of RIPK1， RIPK3， and mixed lineage kinase domain-like （MLKL） in the lung tissue. The protein expressions of RIPK1， RIPK3， and MLKL in the lung tissue were detected by Western blot. The pathological changes in lung tissue were observed by hematoxylin-eosin （HE） staining. ResultCompared with the normal group， the contents of TNF-α and TNFR1 in BALF of the model group were significantly increased （P<0.01）， and the mRNA and protein expression levels of RIPK1， RIPK3， and MLKL in the lung tissue were significantly increased （P<0.01）. Compared with the model group， the contents of TNF-α and TNFR1 in BALF of high， medium， and low-dose groups of modified Erchentang and Xiaokechuan group were decreased （P<0.01）. The mRNA and protein expression levels of RIPK1， RIPK3， and MLKL in the lung tissue were decreased to different degrees （P<0.05， P<0.01）. ConclusionModified Erchentang can effectively improve the inflammatory response of lung tissue in COPD rats， and the mechanism may be by inhibiting the activation of the TNF-α/TNFR1/RIPKs signaling pathway.

Donation after death is the most important ethical principle to carry out organ donation after citizens’ death. The newly-revised Regulations on Human Organ Donation and Transplantation does not define death, and avoids the key question of “whether to recognize brain death”. Certain legal risks or damages to the rights and interests of donors may exist in organ donation. Death is an inevitable part of human life. It is necessary to establish specific criteria, which is also the only approach, to define death in any era. Death criteria are established based on the view of death, and restricted by the development level of productive forces and other social factors. The determination of death criteria hugely varies between China and the West. To standardize organ donation and transplantation and promote high-quality development of organ donation, medical staff must adhere to the principle of pure motivation, take informed consents as the premise, respect the donors' and their close relatives' rights to choose their own death criteria, strictly follow the death judgment procedures and operating norms, and ensure the scientificity, accuracy and fairness of death determination.

BACKGROUND:There are many treatment methods for knee osteoarthritis,among which electroacupuncture,as an important non-drug treatment,is effective in the treatment of knee osteoarthritis,but its exact mechanism is not clear. OBJECTIVE:Effect of electroacupuncture on the expression of p53 and P21 in articular cartilage and subchondral bone of aged rats with knee osteoarthritis. METHODS:Eight 6-month-old male Sprague-Dawley rats were included in the young group and sixteen 24-month-old male Sprague-Dawley rats were randomly divided into old group(n=8)and electroacupuncture group(n=8).The rats in the electroacupuncture group received electroacupuncture stimulation once a day,5 days a week,for 8 continuous weeks,and the other two groups did not do any treatment.Eight weeks later,the level of type Ⅱ collagen C-terminal peptide in peripheral blood was detected by ELISA,the morphology of left knee cartilage and subchondral bone was observed by safranin O-fast green staining,the degree of knee cartilage degeneration was evaluated by modified Mankin's score,the microstructure of left knee cartilage and subchondral bone was detected by micro-CT,and the expression levels of matrix metalloproteinase 13,P53,P21 Mrna and protein were detected by RT-PCR and western blot respectively. RESULTS AND CONCLUSION:Compared with the young group,the level of C-terminal peptide of type Ⅱ collagen in the peripheral blood was increased in the old group(P<0.05).The micro-CT results showed that the bone volume fraction,bone mineral density and the number of bone trabeculae were decreased in the old group compared with the young group(P<0.05),while the trabecular separation increased(P<0.05).Safranin O-fast green staining showed that in the old group,the surface layer of cartilage was uneven with fissures,the morphology of chondrocytes was irregular and stained unevenly,the boundary between the cartilage and subchondral bone was blurred,and the matrix loss was serious.The Mankin's score was higher in the old group than the young group(P<0.05).The expression of matrix metalloproteinase 13,P53,P21 at Mrna and protein levels increased in the old group compared with the young group(P<0.05).Compared with the old group,electroacupuncture decreased the level of C-terminal peptide of type Ⅱ collagen(P<0.05),increased the bone volume fraction,bone mineral density and the number of bone trabeculae(P<0.05),and decreased the trabecular separation(P<0.05).Safranin O-fast green staining showed that in the electroacupuncture group,the surface of cartilage was smooth and red staining was uniform,and the cell morphology and structure were between the young group and the old group.Following electroacupuncture treatment,the Mankin's score(P<0.05),matrix metalloproteinase 13 and P21 Mrna expression(P<0.05),and matrix metalloproteinase 13 and P53 protein expression decreased(P<0.05),while there was a decreasing trend of P53 Mrna and P21 protein expression,but with no statistical significance(P>0.05).To conclude,electroacupuncture may delay articular cartilage degeneration and subchondral osteoporosis in aged rats by inhibiting the expression of P53 and P21,so as to protect joints and delay joint aging.

BACKGROUND:Current studies have confirmed that Ganoderma lucidum polysaccharides can promote nerve regeneration in neurodegeneration-related diseases.The occurrence of neurodegenerative diseases is closely related to mitochondrial dysfunction,but the role of Ganoderma lucidum polysaccharides on the regulation of apoptosis and mitochondrial function in neurodegenerative diseases is not yet clarified. OBJECTIVE:To explore the regulatory effects and mechanisms of Ganoderma lucidum polysaccharides on apoptosis and mitochondrial dysfunction in H2O2-induced SH-SY5Y cells. METHODS:SH-SY5Y cells were divided into three groups:control group,H2O2 group,and Ganoderma lucidum polysaccharides group.Cells in the control group were normally cultured.Cells in the H2O2 group were treated with 300 μmol/L H2O2 for 24 hours.In the Ganoderma lucidum polysaccharides group,the intervention with 300 μg/L Ganoderma lucidum polysaccharides was conducted first for 1-2 hours,followed by the addition of 300 μmol/L H2O2 for 24 hours.The mitochondrial membrane potential was detected by JC-1 kit.Apoptosis was detected by TUNEL staining kit.The activities of malondialdehyde and superoxide dismutase were detected by malondialdehyde test kit and superoxide dismutase test kit,respectively.The apoptosis and expression of mitochondrial dynamics-related proteins were detected by immunofluorescence staining and western blot assay. RESULTS AND CONCLUSION:(1)Compared with the control group,the mitochondrial membrane potential and superoxide dismutase activity were significantly reduced,as well as apoptotic rate and malondialdehyde levels were significantly increased in the H2O2 group(P<0.05).After treatment with Ganoderma lucidum polysaccharides,the membrane potential and superoxide dismutase activities were significantly increased,and apoptotic rate and malondialdehyde levels were significantly reduced compared with the H2O2 group(P<0.05).(2)The expression levels of pro-apoptotic proteins Bax and Caspase-3 were significantly increased,but the expression of anti-apoptotic protein Bcl-2 was significantly decreased in the H2O2 group compared with the control group(P<0.05).Compared with the H2O2 group,the levels of Bax and Caspase-3 were significantly decreased,but the expression of anti-apoptotic protein Bcl-2 was significantly increased in the Ganoderma lucidum polysaccharides group(P<0.05).(3)Compared with the control group,the expression of mitochondrial splitting proteins Fis1 and p-Drp1 was significantly increased,but the expression of mitochondrial fusion proteins OPA1,Mfn1,and Mfn2 was decreased in the H2O2 group(P<0.05).Compared with the H2O2 group,Fis1 and p-Drp1 expression was significantly reduced,but the expression levels of OPA1,Mfn1,and Mfn2 were significantly increased in the Ganoderma lucidum polysaccharides group(P<0.05).(4)The above results confirm that Ganoderma lucidum polysaccharides can attenuate H2O2-induced oxidative stress damage and apoptosis in SH-SY5Y cells by ameliorating mitochondrial dysfunction.

Objective:To explore the microbiological and disease distribution characteristics of multidrug-resistant bacteria in patients hospitalized in a critical care rehabilitation ward, and to analyze the risk factors leading to multidrug-resistant bacterial infections.Methods:Microbiology screening data describing 679 patients admitted to a critical care rehabilitation ward were retrospectively analyzed to divide the subjects into a multidrug-resistant group (positive for multidrug-resistant bacterial infections, n=166) and a non-multidrug-resistant group (negative for multidrug-resistant bacterial infections, n=513). The risk factors were then analyzed using logistic regression. Results:Among 369 strains of multidrug-resistant bacteria observed, 329 were gram-negative bacteria (89.2%), mainly Pseudomonas aeruginosa, Klebsiella pneumoniae and Escherichia coli. They were distributed in sputum (56.9%) and mid-epidemic urine (28.2%) specimens. Patients whose primary disease was hemorrhagic or ischemic cerebrovascular disease accounted for 40.96% and 23.49% of the multidrug-resistant bacterial infections, respectively. Logistic regression analysis showed that albumin level, dependence on mechanical ventilation, central venous cannulation, or an indwelling urinary catheter or cystostomy tube were significant independent predictors of such infections.Conclusion:The multidrug-resistant bacterial infections of patients admitted to the critically ill rehabilitation unit are mainly caused by gram-negative bacteria. Their occurrence is closely related to low albumin levels and mechanical ventilation, as well as to bearing an indwelling central venous catheter, a urinary catheter or a cystostomy catheter.

Objective:To investigate clinical curative effect of multiple composite tissues replantation with microsurgical technique in single hand.Methods:From May 2008 to December 2021, the clinical data of patients who underwent multiple composite tissue replantation in single hand in Chongming Hospital Affiliated to Shanghai University of Medicine & Health Sciences and Taizhou Hospital of Zhejiang Province, Wenzhou Medical University, were retrospectively analyzed. According to the severed site, anatomical level, the injury cause, the severity of injury, the size of severed tissue, and replantation conditions (such as blood vessels for anastomosis), the severed tissue was evaluated and carried out modified classification (type Ⅰ-Ⅳ) before the operation, and the surgical plan was designed. The severed composite tissue was debrided in emergency, the severed bone and muscle tissue were fixed, and the arteries, veins and nerves were anastomosed by microsurgical technique under a high-power microscope. The ratio of arteries to veins was 1∶1-1∶2. If enough arteries and veins could not be found, arteriovenous shunt could be used to form arterial venous flap or venous arterialized flap, or form artery flap by just artery anastomosis, or form venous flap by just vein anastomosis. Then skin tissue was sutured after recanalization. After the operation, the patients received specialized treatment and guided rehabilitation exercise. The wound healing of hand, skin color, skin quality, swelling degree, sensation, pain degree of joint, and activity function were followed up after the operation. At the last follow-up, the patient’s self-evaluation of the treatment effect was divided into three levels: satisfactory, average, and unsatisfactory. One chief physician and one doctor-in-charge were responsible for the comprehensive evaluation of curative effect, according to the assessment standard for upper limb function issued by Chinese Medical Association of Hand Surgery. 80-100 points were excellent, 60-79 points were good, 40-59 points were fair, and <40 points were poor.Results:A total of 94 severed composite tissues in 35 patients, including of 20 male patients and 15 female patients were enrolled. The average age was 36.4 years (range, 16-65 years). Fifty severed tissues in 18 cases were classified into type Ⅰ, 40 severed tissues in 15 cases type Ⅱ, 4 severed tissues in 2 cases type Ⅲ. Among the 35 cases, 1 case of thumb pulp severed tissue was necrotic at the edge (0.3 cm×0.5 cm) due to local contusion, 1 case of index finger lateral severed tissue was necrotic at the edge (0.3 cm×0.8 cm) due to local avulsion injury, and healed after dressing change, and the other replanted composite tissue survived. The patients were followed up for 3 to 65 months (average, 18.5 months). The wounds were completely healed, and the color, elasticity, and quality of the replanted tissue was close to the surrounding normal skin. There was no obvious swelling or atrophy deformity of the hands. According to the patients’ self-assessment, 31 cases were satisfied and 4 cases were average. Comprehensive evaluation of hand function and appearance: excellent in 23 cases, good in 9 cases, fair in 3 cases, excellent and good rate was about 91.4% (32/35).Conclusion:Though multiple composite tissues replantation with microsurgical technique in single hand is difficult, and vascular anastomosis technical requirement is high, once surgery succeeds, the function and appearance can get good recovery, and patient satisfaction is also relatively high.

Subchondral bone cysts after cartilage repair are abnormal cavities that develop near the site of repaired cartilage defects and may communicate with the joint cavity.Research indicates that they may be associated with factors such as elevated external hydraulic pressure, bone bruising due to abnormal stress, internal inflammation, and inadequate blood supply.These cysts are closely linked to bone marrow edema.It has been observed that cysts following cartilage repair frequently occur after various procedures, including bone marrow stimulation, autologous or allogeneic osteochondral transplantation, and autologous chondrocyte transplantation.They represent a significant pathological change post-cartilage repair, influencing the process, quality, and outcome of the repair.Consequently, they have become an important parameter for evaluating the effectiveness of cartilage repair.This article provides a review of studies on the occurrence, development mechanisms, and pathological structures of subchondral bone cysts after cartilage repair using different techniques.It explores the clinical implications and potential of utilizing these cysts to assess the success of cartilage repair, enhancing understanding in this field.Such insights are expected to lay a foundation for the prevention and treatment of subchondral bone cysts following various cartilage repair procedures.

Objective:To understand the major cognition, major choice motivation and the relationship between the two of medical students, and provide references and suggestions for the selection of talents in various majors of medical schools and the effective development of enrollment work.Methods:This study selected undergraduates of Batch 2019 from Peking University Health Science Center as the survey objects, conducted a questionnaire survey on their major cognition, major choice motivation and influencing factors, and used principal component analysis and Spearman rank correlation analysis.Results:The study found that the major cognition scores of 640 undergraduates of Batch 2019 from Peking University Health Science Center were clinical medicine (3.24±0.89) > stomatology (2.89±1.00) > basic medicine (2.66±1.02) > pharmacy (2.54±0.97) > preventive medicine (2.29±0.93) > nursing medicine (2.21±0.99) > medical laboratory (1.98±0.95) > medical English (1.95±0.93). Six major motivation factors for professional choice were school and professional strength, professional learning and job prospects, own factors, Peking University sentiments and the influence of others, medical factors, school policies, and the contribution rates were 34.60%, 12.97%, 7.42%, 6.00%, 5.59% and 5.37%, respectively. Major cognition scores and major choice motivation factors were positively correlated with each other to some extent.Conclusions:At present, students' major cognition level of medical majors still has a large room for improvement, and the motivational factors of major choice are more complicated, among which "the school and professional strength" and "the prospects of study and work" are important factors. Medical schools should focus on strengthening major publicity, improving students' major cognition, attracting aspiring students to apply for medical majors from many aspects, and improving the training quality of medical professionals.