ObjectiveTo evaluate the role of Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) signaling pathway in attenuation of myocardial ischemia-reperfusion (I/R) injury by tetramethylpyrazine in rats.MethodsSixty-four healthy male Wistar rats weighing 250-300 g were randomly divided into 4 groups( n ＝ 16 each):sham operation group (group S),myocardial I/R group(group I/R),teramethylpyrazine group (group T) and AG,490( a JAK2 inhibitor) group (group AG).Myocardial I/R was induced by 30 min occlusion of left anterior desecending coronary artery (LAD) followed by 120 min reperfusion in groups I/R,T and A.In groups T and A teramethylpyrazine 20 mg/kg was injected iv 20 min before LAD occlusion.In group A AG490 3 tμg/g was injected iv at 5 min before reperfusion.Blood samples were then taken from inferior vena cava at 120 min of reperfusion for measurement of serum creatine phosphokinase (CK) and lactose dehydrogenase (LDH) activities.Myocardial infarct size was then measured and myocardial tissue was obtained for microscopic examination.ResultsSerum CK and LDH activities were significantly higher in group I/R than in group S.Pretreatment with tetramethylpyrazine significantly decreased myocardial infarct size and I/R-induced increase in serum CK and LDH activities and histologic damage.The protective effect of tetramethylpyrazine against myocardial 1/R injury was attenuated by postconditioning with AG490.ConclusionJAK2/STAT3 signaling pathway is involved in attenuation of myocardial I/R injury by tetramethyl pyrazine in rats.

Objective To evaluate the effect of living skin equivalents (LSE) constructed of mixed autologous and allogeneic skin cells and human amnion which served as a matrix on repairing scar contracture of the hand in a patient with recessive dystrophic epidermolysis bullosa (RDEB).Methods Skin tissues were obtained from a patient with RDEB and her mother,and epidermal keratinocytes and dermal fibroblasts were isolated from these tissues and cultured in vitro separately.Human amnion was obtained from the placenta of an unrelated healthy parturient undergoing cesarean delivery,and served as a matrix of the LSE.The autologous and allogeneic fibroblasts were mixed and seeded on the stromal side of the amnion,and then the autologous and allogeneic keratinocytes were mixed and seeded on the epithelial side of the amnion,so as to construct the human amnion-LSE (AM-LSE).Histological examination was performed to observe the structure of the skin tissues obtained from the patient and her mother,and immunofluorescence staining was conducted to detect the expression of type Ⅶ collagen in the skin tissues of the patient and her mother and in the AM-LSE.The AM-LSE was grafted on the skin defects of the patient after release of scar contracture of the hand.After grafting,the survival status of the AM-LSE graft and repairing effect on the wounds were evaluated.Results The constructed AM-LSE consisted of dermis,multilayered and fully differentiated epidermis and well-developed basement membrane.Immunofluorescence examination revealed that type Ⅶ collagen was linearly distributed along the basement membrane.Half a year after grafting,the AM-LSE survived well,and no obvious rejection reaction was observed.No blisters or ulcers occurred at the recipient sites,and the scar contracture was mild.The grafted area showed normal skin color with soft texture.The patient could grab and hold things,which had met self-care requirements of daily living.Conclusions The AM-LSE constructed of mixed autologous and allogeneic skin cells have good histological structures,and can be grafted on the wounds after resection of the scars in a RDEB patient.After grafting,no obvious rejection reaction was observed,and the skin was not liable to develop blisters,ulcers or scar contracture due to friction.

【Objective】 To explore the safety of RhD-positive red blood cells (RBCs) immunization schedules in RhD-negative volunteers, so as to facilitate the development of domestic anti-D immunoglobulin. 【Methods】 From January 2018 to April 2020, 23 RhD negative volunteers with informed consent were enrolled and divided into initial immunization group and booster immunization group. The initial immunization included first immunization, second immunization and third immunization. Four groups, i. e. 3 cases of 20 mL, 8 of 30 mL, 6 of 40 mL, and 6 of 50 mL, were involved in initial immunization. After the initial immunization response, booster immunizations were performed every 3 months. According to the anti-D titer before each immunization, the booster immunization doses were set to 0.5, 1 and 2 mL. Whole blood samples of 5mL/ person (time) were collected 24 h and 1 week after each infusion, and the blood routine, liver, kidney and blood coagulation function and anti-D titer were detected. The differences of detection (index) values at 24 h and 1 week after the first immunization and booster immunization in each (dose) group were compared. 【Results】 No statistically significant differences were observed in hemolysis index values (all within the range of medical reference values) 24 h or 1 week after initial immunization among RhD positive RBCs of 20, 30, 40 and 50mL(P>0.05). The differences between the hemolysis index values and the basic values before the immune response (all within the range of medical reference values) after 0.5 or 1 mL booster immunizations were also not statistically different (P>0.05). However, the differences (μmol/L)between total bilirubin levels and the basic values before the immune response (1.55±1.87, 6.29±2.66) were significantly different after 2 mL booster immunization (P<0.05). 【Conclusion】 No risks affecting the safety of RhD negative volunteers was found in the immunization schedule proposed in this study.