Objective To explore the mechanism underlying the protective effect of α2-macroglobulin (A2M) against glucocorticoid-induced femoral head necrosis. Methods In a human umbilical vein endothelial cell (HUVEC) model with injuries induced by gradient concentrations of dexamethasone (DEX;10-8-10-5 mol/L), the protective effects of A2M at 0.05 and 0.1 mg/mL were assessed by examining the changes in cell viability, migration, and capacity of angiogenesis using CCK-8 assay, Transwell and scratch healing assays and angiogenesis assay. The expressions of CD31 and VEGF-A proteins in the treated cells were detected using Western blotting. In BALB/c mouse models of avascular necrosis of the femoral head induced by intramuscular injections of methylprednisolone, the effects of intervention with A2M on femoral trabecular structure, histopathological characteristics, and CD31 expression were examined with Micro-CT, HE staining and immunohistochemical staining. Results In cultured HUVECs, DEX treatment significantly reduced cell viability, migration and angiogenic ability in a concentration- and time-dependent manner (P<0.05), and these changes were obviously reversed by treatment with A2M in positive correlation with A2M concentration (P<0.05). DEX significantly reduced the expression of CD31 and VEGF-A proteins in HUVECs, while treatment with A2M restored CD31 and VEGF-A expressions in the cells (P<0.05). The mouse models of femoral head necrosis showed obvious trabecular damages in the femoral head, where a large number of empty lacunae and hypertrophic fat cells could be seen and CD31 expression was significantly decreased (P<0.05). A2M treatment of the mouse models significantly improved trabecular damages, maintained normal bone tissue structures, and increased CD31 expression in the femoral head (P<0.05). Conclusion A2M promotes proliferation, migration, and angiogenesis of DEX-treated HUVECs and alleviates methylprednisolone-induced femoral head necrosis by improving microcirculation damages and maintaining microcirculation stability in the femoral head.

Objective To explore the mechanism underlying the protective effect of α2-macroglobulin (A2M) against glucocorticoid-induced femoral head necrosis. Methods In a human umbilical vein endothelial cell (HUVEC) model with injuries induced by gradient concentrations of dexamethasone (DEX;10-8-10-5 mol/L), the protective effects of A2M at 0.05 and 0.1 mg/mL were assessed by examining the changes in cell viability, migration, and capacity of angiogenesis using CCK-8 assay, Transwell and scratch healing assays and angiogenesis assay. The expressions of CD31 and VEGF-A proteins in the treated cells were detected using Western blotting. In BALB/c mouse models of avascular necrosis of the femoral head induced by intramuscular injections of methylprednisolone, the effects of intervention with A2M on femoral trabecular structure, histopathological characteristics, and CD31 expression were examined with Micro-CT, HE staining and immunohistochemical staining. Results In cultured HUVECs, DEX treatment significantly reduced cell viability, migration and angiogenic ability in a concentration- and time-dependent manner (P<0.05), and these changes were obviously reversed by treatment with A2M in positive correlation with A2M concentration (P<0.05). DEX significantly reduced the expression of CD31 and VEGF-A proteins in HUVECs, while treatment with A2M restored CD31 and VEGF-A expressions in the cells (P<0.05). The mouse models of femoral head necrosis showed obvious trabecular damages in the femoral head, where a large number of empty lacunae and hypertrophic fat cells could be seen and CD31 expression was significantly decreased (P<0.05). A2M treatment of the mouse models significantly improved trabecular damages, maintained normal bone tissue structures, and increased CD31 expression in the femoral head (P<0.05). Conclusion A2M promotes proliferation, migration, and angiogenesis of DEX-treated HUVECs and alleviates methylprednisolone-induced femoral head necrosis by improving microcirculation damages and maintaining microcirculation stability in the femoral head.

Objective:To explore the effects of G protein-coupled receptor 55 (GPR55) antagonist CID16020046 on renal fibrosis in mice, and provide a new method and idea for the treatment of renal fibrosis.Methods:(1) GPR55 overexpression and GPR55 antagonist CID16020046 were used in renal fibroblasts (NRK-49F) of rats, respectively. Meanwhile,transforming growth factor-β1 (TGF-β1) was applied in the NRK-49F cells to observe the expression of fibrosis-related factors and inflammatory factors. (2) A mouse model of renal fibrosis with unilateral ureteral obstruction (UUO) was established in vivo. Eight-week-old male C57BL/6J mice (20-25 g) were randomly divided into three groups according to the random number table method: sham group ( n=6), model group (UUO group, n=7), model + CID16020046 drug (UUO+CID group, n=8). The drug CID16020046 (10 mg/kg) was intraperitoneally injected 1 day before modeling, on the day of modeling and every day after surgery in UUO+CID group, and the corresponding dose of 0.9% normal saline was injected intraperitoneally in sham and UUO groups.The mice were sacrificed for sampling 7 days after UUO surgery, and their renal function indicators, liver transaminase, and cardiac markers were examined. Western blotting and quantitative real-time PCR were used to detect the expression of renal fibrosis-related factors and inflammatory factors. Immunohistochemistry staining, Sirius red staining and Masson trichrome staining were used to detect the pathological changes of renal tissues. Results:(1) After NRK-49F cells were stimulated by TGF-β1, the mRNA and protein expression levels of GPR55 were significantly increased (both P<0.05). There was no statistically significant difference in the mRNA expression of fibrosis-related factors fibronectin and collagen Ⅰ, and inflammatory factors interleukin-1β and tumor necrosis factor-α between TGF-β1 group and TGF-β1 + GPR55 overexpression group (all P>0.05). Compared with the TGF-β1 group, the protein expression levels of fibrosis-related factors alpha-smooth muscle actin (α-SMA) and vimentin, and the mRNA expression levels of collagen Ⅰ and α-SMA were lower in the TGF-β1 + CID group (all P<0.05). (2) Compared with sham group, the mRNA and protein expression levels of GPR55 in UUO group were higher (both P<0.05). The serum creatinine in the UUO+CID group was lower compared to the UUO group ( P<0.05). There was no statistically significant difference in blood urea nitrogen, alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase and creatine kinase isoenzyme between UUO group and UUO+CID group (all P>0.05). Compared with the UUO group, the protein expression levels of renal fibrosis-related factors fibronectin, collagen Ⅰ and vimentin, and the mRNA expression levels of fibronectin, collagen Ⅰ, collagen Ⅲ and α-SMA were lower in the UUO+CID group (all P<0.05). The degree of renal tubular dilation and interstitial collagen fiber deposition in the UUO+CID group was significantly reduced compared to the UUO group (all P<0.05). Conclusions:CID16020046 can reduce serum creatinine in UUO mice, protect renal function, and simultaneously decrease the expression of fibrosis-related factors in renal fibroblasts and mouse kidney tissues, thereby alleviating renal fibrosis.

Objective: To investigate the awareness and identify the influencing factors of sexual knowledge among primary and middle school students in Butuo County, Sichuan Province, so as to provide insights into sex education. Methods: Six primary and middle schools were randomly sampled from 40 primary and middle schools in Butuo County using the cluster sampling method on March and April, 2021, and a class was randomly sampled from each of grades 4 to 6 of primary schools and grades 1 to 3 of junior high schools, with all students from the class as study subjects. Students' demographic features and awareness of sexual knowledge were investigated using self-designed questionnaires, and the factors affecting the awareness of sexual knowledge were identified among primary and middle school students using multivariable linear regression analysis. Results: A total of 980 questionnaires were allocated, and 957 valid questionnaires were recovered, with an effective recovery rate of 97.65%. The respondents included 458 boys ( 47.86% ) and 499 girls ( 52.14% ), and included 908 students with Yi Ethnicity. The respondents included 802 primary school students ( 83.80% ) and 155 junior high school students ( 16.20% ). The awareness of sexual knowledge was 21.94% among the primary and middle school students, and their sexual knowledge was predominantly derived from parents ( 338 students, 35.32% ) and teachers ( 335 students, 35.01% ). The awareness of sexual knowledge was significantly lower in boys than in girls ( 17.69% vs. 25.86%; χ2=8.344, P=0.004 ), and the awareness of sexual knowledge appeared a tendency towards a rise with age ( χ2trend = 63.908, P<0.001 ). Low awareness of sexual knowledge was seen in students with fathers going out for labor ( 19.54% ), mothers going out for labor (11.24%) and living in the countryside ( 14.32% ) ( χ2=7.790, 9.224 and 34.144, all P<0.01 ). Multivariable linear regression analysis showed that students living in the countryside, students’ mothers going out for labor, ages of 12 to 14 years and ages of over 14 years were factors affecting the score of sexual knowledge ( β'=-0.072, 0.341, 0.645 and 0.843, all P<0.05 ). Conclusions The awareness of sexual knowledge is low among primary and middle school students in Butuo County. Health education of sexual knowledge should be emphasized on male students, those living in the countryside and students with mothers going out for labor.

Fatal arrhythmias, heart failure, and sudden cardiac death after myocardial ischemia/infarction are serious threats to human health. In recent years, studies have shown that spinal cord stimulation (SCS) can balance autonomic activity, inhibit myocardial structural remodeling, improve blood flow to ischemic myocardium, effectively reduce the incidence of arrhythmia, heart failure and sudden cardiac death after myocardial ischemia/infarction, but its specific mechanism has not yet been fully elucidated. The effect of SCS on cardiac function may be achieved by inhibiting neural remodeling, or by ameliorating structural remodeling and electrical remodeling. This article reviews the progress on the role and mechanism of SCS in myocardial ischemia/infarction.
Coronary Artery Disease ; Heart Failure ; Humans ; Myocardial Infarction ; therapy ; Myocardial Ischemia ; Myocardium ; Spinal Cord Stimulation

Objective To evaluate the left atrial(LA) function in patients with severe preeclampsia ( SPE) by full-volume imaging technology. Methods Forty-two patients of SPE were randomly chosen as SPE group,34 healthy pregnant women were selected as the control group. LA related function parameters including LA maximum volume( LAVmax),LA minimum volume( LAVmin),LA pre-atrium contraction volume(LAVpre),LA reservoir volume(LARV),LA passive emptying volume(LAPEV),LA contraction volume(LACV),LA expansion index(LAEI),LA passive emptying fraction(LAPEF),LA passive emptying fraction( LAAEF ) were separately required by biplane area-length method and full-volume imaging technology in antepartum and postpartum. Results Compared with control group before delivery,the parameters of SPE group before delivery such as LAVmax,LAVmin,LAVpre were higher,LAEI,LAPEF, LAAEF indexed to body surface area(BSA) were lower(all P ＜0.01).Compared with control group before delivery,the parameters of control group after delivery such as LAVmax,LAVmin,LAVpre were lower( all P ＜0.05),LAEI, LAAEF calculated as ratio to BSA were somewhat reduced,LAPEF calculated as ratio to BSA was relatively higher(all P ＞0.05).Compared with SPE group before delivery,the parameters of SPE group after delivery such as LAVmax,LAVmin,LAVpre were lower,LAEI,LAPEF,LAAEF indexed to BSA were higher( all P ＜0.01). Compared with control group after delivery,the parameters of SPE group after delivery such as LAVmax,LAVmin,LAVpre were still incresed ( all P ＜ 0.05 ), LAEI,LAPEF, LAAEF indexed to BSA were relatively lower( all P ＞0.05). Conclusions Full-volume imaging technology can quantitatively evaluate the LA function. LA reservoir function,conduit function and booster pump function are reduced in SPE before delivery,LA rereservoir function,conduit function and booster pump function are basically recovery in SPE after delivery.

Objective To explore the effect of internet + continuing nursing education teaching methodflipped classroomin the teaching of Assessment of Consciousness among junior nurses. Methods A total of 98 nurses who have graduated within two years in the third hospital of Mianyang city in Sichuan province were selected and divided into experimental group and control group by random digits table method with 49 nurses each. The experimental group used flipped classroom teaching method and the control group used the traditional teaching method. After the training, the scores of examination and nurses′ learning satisfaction were analyzed and compared. Results The scores of nurses′ learning satisfaction in the experimental group was (100.35 ± 12.21) points, learning process, learning content, learning result, learning environment, interpersonal relationship of the dimensions were (26.85 ± 3.38), (22.02±3.07), (20.90±3.15), (17.19±2.50), (13.40±1.51) points. The scores of nurses′learning satisfaction in the control group was (86.00±11.63) points, learning process, learning content, learning result, learning environment, interpersonal relationship of the dimensions were (23.63±2.81), (19.67±3.06), (17.76±3.32), (15.20±2.46), (9.74±2.74) points. There were statistical differences between two groups(t=3.46-7.97, all P=0.000). The score of nurses′examination in the experimental group was (78.19±6.11) points,the score of nurses′ examination in the control group was (49.64 ± 14.42) points, and there was statistical difference between two groups(t=10.19, P=0.000). Conclusions Internet+continuing nursing education teaching methodflipped classroomcan improve junior nurses′learning satisfaction and the effect of the training, worthy of further promotion.

Objective To evaluate the validity and reliability of learning attitude scale among nurses in continuing nursing education in hospital.Methods We designed a nurse learning attitude scale in continuing education on the basis of a learning attitude questionnaire for teacher-training by Jiao Weiting. In July 2015, totally 207 nurses of the Third Hospital of Mianyang who received continuing education in hospital were selected as the research object by cluster sampling method. We investigated their learning attitudes. The reliability of the scale was assessed by Cronbach's α coefficient and test-retest reliability. The validity was assessed by factor analysis and Pearson's correlation.Results The test-retest reliability of the scale were as the following:cogni-tive level (0.82),experience of emotion (0.89),tendency of behavior (0.91),total scale (0.88);Cronbach's α co-efficients were as the following:cognitive level (0.85),experience of emotion (0.94),tendency of behavior (0.83), total scale (0.89). According to the result of Pearson's correlation,the total scale of learning attitude exhibited a positive correlation with cognitive level,experience of emotion and tendency of behavior (P<0.01). Four prin-cipal components were extracted by factor analysis and the constructs of the instrument obtained were consistent with the conceived concept in essence.Conclusions The scale learning attitude could measure the learning attitude of nurses in continuing nursing education with better reliability and validity.

Objective To determine the effects of β-estradiol on vasoconstriction in human umbilical artery and vein and its potential mechanisms.Methods Human umbilical cord samples were obtained from 96 term neonates of healthy singleton pregnant women born in the First Hospital of Soochow University between December 2013 and June 2015 (multiple pregnancy,pregnancy complications,cesarean delivery and low birth weight were excluded).Human umbilical arteries and veins were isolated and suspended in 37 2 organ baths containing 5 ml Krebs solution and exposed to β-estradiol followed by phenylephrine (PE) for vasoconstriction test.The subjects were divided into β-estradiol group and control group according to the presence or absence of β-estradiol incubation.To determine the effects and the possible underlying mechanisms of β-estradiol on PE-induced vasoconstriction,human umbilical artery and vein rings were pretreated with N ω-nitro-L-arginine (L-NMMA,nitric oxide synthesis inhibitor),fulvestrant (ICI182780,estradiol receptor antagonist),indomethacin (prostaglandin synthesis blocker),and removal of endothelium,then incubated with β-estradiol for 60 min followed by PE,and the concentration-response curves to PE were recorded.The concentrationresponse curves to phorbol 12,13-dibutyrate (PDBU,protein kinase C agonist) in Krebs solution in the presence or absence of β-estradiol were also obtained.Nonlinear regression and fitting curve were performed,and the two-sample ANOVA was used for analysis.Results (1) β-estradiol suppressed PE-induced vasoconstriction of human umbilical vein and artery.In human umbilical vein and artery of the control group,the maximum contraction intensity induced by PE was (59.17± 5.98)％ and (43.35± 5.02)％ of that induced by potassium chloride,respectively.The maximum contraction induced by PE in β-estradiol group was (5.87± 1.32)％and (4.52±1.22)％ of that induced by potassium chloride.(2) In both groups,incubation with L-NMMA or endothelium removal enhanced the vasoconstriction of human umbilical artery and vein,indicating that the inhibitory effect of β-estradiol was not influenced by the endothelium.(3) The suppression of β-estradiol on PE-induced vasoconstriction in human umbilical artery and vein was not significantly decreased by estrogen receptor antagonist.(4) β-estradiol did not affect human umbilical artery and vein vasoconstriction induced by PDBU.(5) In the control group,incubation with indomethacin did not affect human umbilical artery and vein vasoconstriction induced by PE.In the β-estradiol group,indomethacin significantly enhanced the contraction response induced by PE,suggesting that prostacycline synthesis was partly involved in β-estradiol-suppressed contractility in human umbilical artery and vein.The contractile response induced by phenylephrine was still lower in the β-estradiol group than in the control group,which was induced by indomethacin.Conclusions (1) β-estradiol can suppress vasoconstriction in human umbilical artery and vein,which is not dependent on endothelium and estrogen receptors,or protein kinase C activity,(2) Prostacycline synthesis is partly involved in β-estradiol-suppressed vasoconstriction in human umbilical artery and vein.

10.3969/j.issn.2095-4344.2013.26.002