Biocompatibility of extracellular matrix hydrogel with human iPSCs differentiated cardiomyocytes / 中华心血管病杂志

Objective: To observe the biocompatibility of porcine omental derived extracellular matrix (ECM) hydrogel with human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) and the feasibility of ECM hydrogel as a delivery vector of cell transplantation. Methods: A series of chemical, physical and enzymatic methods were applied to acellularize the porcine omentum. Subsequently, the extracted ECM was prepared into thermosensitive hydrogel. The biochemical composition of the hydrogel was identified by histological staining. The microstructure was observed by scanning electron microscopy. The hydrogel was then injected into the myocardium of mice to observe its in situ gelation ability. Differentiation of human induced pluripotent stem cells into cardiomyocytes was achieved by small molecule induction, and then the obtained hiPSC-CMs were cultured. hiPSC-CMs cultured onto the prepared hydrogel were defined as the hydrogel group, while conventionally cultured hiPSC-CMs were defined as the control group. Cardiomyocyte viability and growth patterns were detected using live/dead staining, CCK-8 and phalloidin staining. Immunofluorescence staining and Western blot of cardiomyocytes were used to determine the survival and phenotypic maintenance markers of cardiomyocytes in materials. Results: The results of HE staining, oil red O staining and DAPI fluorescence staining showed that there was no significant cell debris, nucleus and lipid residue in the prepared ECM hydrogel. The Sirius red staining and Alcian blue staining showed that the hydrogel retained collagen and glycolaminoglycan, which were the main components of ECM. The prepared hydrogel behaves as a viscous liquid at 4 ℃ and as a gel state at 37 ℃. Scanning electron microscope results showed that the microstructure of the hydrogel was composed of irregular fibers and pores of different sizes. Under the guidance of ultrasound, the prepared ECM hydrogel could be successfully injected into the myocardium of mice. Immediately after the injection, the hyperechoic signal could be observed under ultrasound, suggesting that the hydrogel remained in the myocardium. HE staining of myocardial tissue evidenced that there was lump of gel in the injection area. The differentiated hiPSC-CMs were co-cultured with the prepared ECM hydrogel, and the results of live/dead staining showed that most of the hiPSC-CMs in the hydrogel group and the control group were alive, dead cells were scanty. The results of CCK-8 test showed that the absorbance values of the two groups were similar (P>0.05). The results of phalloidin staining showed that hiPSC-CMs could extend normally when co-cultured with ECM hydrogel. The cell morphology of the hydrogel group was similar with that of the control group, and there was no statistically significant difference in the F-actin coverage area per cell between the two groups (P>0.05). Immunofluorescence staining of cardiomyocyte markers showed that there was no significant difference in the coverage area of α-actinin and connexin-43 (Cx-43) per field between the hydrogel group and the control group (both P>0.05), the quantitative results of DAPI staining showed that there was no statistically significant difference in the number of cells between the two groups (P>0.05). Meanwhile, the results of Western blot showed that the expression levels of α-actinin and Cx-43 in cardiomyocytes in the hydrogel group were similar as those in the control group (both P>0.05). Conclusions: These results show that preparation of the ECM hydrogel from porcine omentum is successful. The hydrogel has good biocompatibility and no obvious cytotoxicity. Besides, the hydrogel can support the survival of hiPSC-CMs in vitro and maintain its phenotype. These properties make it a promising injectable cardiac tissue engineering material.

Study on the relationship between smoking behavior and other unhealthy behaviors among middle school students in 4 cities of China / 中华流行病学杂志

<p><b>OBJECTIVE</b>To explore the situation of smoking behavior among the students of middle school in Beijing, Hangzhou, Wuhan and Urumchi and to analyze the relationship between smoking behavior and several unhealthy behaviors together with psychological troubles to provide evidence in developing an early intervention plan.</p><p><b>METHODS</b>The National Health Education Institute (NHEI) of Chinese Center for Disease Control and Prevention (CDC) provided relevant data on all middle schools in the 4 cities and then U.S. CDC randomly sampled 100 common middle schools from them with a special sampling process. The core questionnaire developed by the experts from WHO and other countries was used in the survey among 9015 sampled students.</p><p><b>RESULTS</b>Among all the sampled students, 29.4% of them had ever attempted cigarettes smoking while 6.6% of them tried tobacco in the 30 days before survey, 27.0% of the students with smoking behavior began smoking at the age of 9 or younger, 31.8% had learned how to refuse smoking from school education. The students with smoking behavior were more likely to drink alcohol, use drugs, bully others, be injured, miss classes, and have some psychological troubles than those without smoking behavior.</p><p><b>CONCLUSION</b>There were increasing trends noticed on the incidence of attempt and smoking cigarettes. Smoking was closely related to other unhealthy behaviors and psychological troubles. Comprehensive education activities on "no-smoking" should be implemented as early as possible among adolescents, as well as to promote training on life skills.</p>

Alcohol consumption and drug use among middle school students aged 13-15 in 4 cities of China / 中华流行病学杂志

<p><b>OBJECTIVE</b>To provide data on alcohol consumption and drug use among middle-school students aged 13-15 in 4 cities of China, and to provide evidence for developing intervention strategies on adolescents alcohol and drug use.</p><p><b>METHODS</b>Standardized sample selection process of two-stage cluster-sampling was used in middle-school students in Beijing, Hangzhou, Wuhan and Urumchi. A self-administered questionnaire survey was conducted in Sept. 2003 and data was analyzed by Epi Info software.</p><p><b>RESULTS</b>Among 7344 students from grade 1 to 3, 36.5% had tasted while 14.4% had drunk alcohol in the past 30 days. 9.9% had experienced drunkness, 5.1% had been in trouble because of drinking, and 1.6% had ever used illegal drugs. Significant differences had been found in all the cities. Higher graders, older students and boys had higher rates of alcohol and addictive drug use than low graders, younger students and girls. 51.9% had been taught on take alcohol safety and another 27.6% on skills of rejecting alcohol, during the past school year.</p><p><b>CONCLUSIONS</b>The current situation of alcohol and addictive drug use among Chinese middle-school students aged 13-15 seemed to be quite critical, suggesting that it is necessary to carry out relevant health education in accordance with different characteristics in area, gender and age of the students.</p>

Study on health related behaviors and its protective factors of junior middle school students in 4 cities of China / 中华流行病学杂志

<p><b>OBJECTIVE</b>To provide accurate data on health related behaviors and protective factors among students in middle schools in China, for developing priorities, programs and policies on health education.</p><p><b>METHODS</b>We used a standard scientific sample selection process developed by American Center for Disease Control and Prevention (CDC) to conduct the questionnaire survey among middle schools from four cities--Beijing, Hangzhou, Wuhan and Urumchi.</p><p><b>RESULTS</b>Data were found as: 3.2% of students are overweight; 25.3% of students rarely washing hands before eating at school, 20.5% of the students had seriously injured in the past 12 months, 30.4% of male students having had physical fighting, 17.1% of the students having serious attempted suicide, 29.7% of the students ever tried or experimented cigarette smoking, 13.0% having drunk from alcohol and 14.5% having been offered or selling drugs during the past 30 days, 78.9% were in an insufficient amount of physical activity and only 14.3% often used seat belt when riding in a car.</p><p><b>CONCLUSIONS</b>There were many problems on health related behaviors among middle school students in these four cities, especially on hygiene, physical activities, psychological situation, smoking and drinking etc. It is absolutely necessary to develop health education for children and adolescence to promote their healthy behaviors and lifestyle.</p>