ABSTRACT
【Objective:】 To summarize the research status, problems and countermeasures of ethical issues related to volunteer action in public health emergencies by reviewing relevant literature. 【Methods:】 Using four keywords: public health emergencies, volunteers, ethics, and research, this paper searched the Chinese and English databases for the literature published from December 2006 to December 2021 (15 years in total) on "ethical research on volunteer action in public health emergencies". After searching, it was found that there were not many related papers. A total of 31 papers were retrieved, and only 23 papers were selected. 【Results:】 The ethical problems faced by volunteers in public health emergencies were complex and diverse, and the individual ethical behavior of volunteers was affected by many factors. The strategies to solve the relevant ethical issues were not yet perfect. 【Conclusions:】 The ethical issues related to volunteer actions in public health emergencies needed to be further studied.
ABSTRACT
OBJECTIVE To explore the toxic effects of zinc oxide nanoparticls (ZnO-NPs) on cardiac development of zebrafish embryos and rat myocardial cell lines (H9c2),as well as potential molecular mechanisms.METHODS ZnO-NPs were characterized.Zebrafish embryos were exposed to different doses of ZnO-NPs (0,0.5,2.5,5.0 and 10.0 mg· L-1) for 24 to 96 h at 4 h post fertilization (4 hpf).The embryo mortality was observed.The expressions of notochord homeobox (noto),T-box 6 (tbx16),T,brachyury homolog a(ta),and tbx6 which were related to cardiac mesoderm were investigated using real-time PCR at 17 hpf.The heart rate and number of cardiomyocytes of embryos [[Tg (cmlc2:nucdsRed)] exposed to 0,2.5 and 5 mg· L-1 ZnO-NPs were detected at 72 hpf.Rat myocardial cell lines (H9c2) were treated with ZnO-NPs (0.1,0.5,1.0,5.0 and 10.0 mg· L-1) for 24 h.Cell viability was measured with Alamar Blue method.Mitochondrial ultrastructure was observed by transmission electron microscopy.Cellular ATP was detected using chemiluminescence,and oxygen consumption rate (OCR) was examined with Seahorse instrument.RESULTS The particle size of ZnO-NPs was (331 ±3)nm.The ZnO-NPs LC50 of zebrafish embryos at 48 hpf was 21.81 mg· L-1.The mRNA expressions of noto,ta and tbx6 were reduced after ZnO-NPs 2.5 mg· L-1 treatment at 17 hpf.The heart rate of 72 hpf zebrafish was 153 min-1 in the ZnO-NPs 5 mg· L-1 group,12.6％ lower than that in the cell vehicle group (P＜0.01),and the number of cardiomyocytes decreased by 15.5％ (P＜0.01) compared with the cell vehicle group.Reduced cell viability and mitochondrial vacuolation were observed in H9c2 after ZnO-NPs 0.5 mg· L-1 exposure.Compared with the cell vehicle group,the cell ATP decreased by 25.7％ (P＜0.05),and OCR decreased by 27.2％ (P＜0.01).CONCLUSION Low-dose ZnO-NPs exposure has effect on the cardiac development of zebrafish,mainly due to reduced heart rate and decreased number of cardiomyocytes.These changes may be related to the decreased expressions of cardiac development-related genes and the impairment of mitochondrial structure and function.
ABSTRACT
Phospholipase C (PLC) is a key enzyme in phosphatidyl inositol turnover during signal transduction. The 12 mammalian PLC isozymes identified to date can be divided into five subtypes, beta-type, gamma-type, delta-type, epsilon-type and zeta-type, with extensive difference in structure, regulatory mechanism and tissue distribution. PLC plays important roles not only in sperm acrosome reaction but also in egg activation. The present studies are reviewed on the structure, regulation and function of PLC, especially its function in male reproduction, including triggering Ca2+ oscillations in eggs to activate the eggs and helping embryo development. And the prospect of the clinical application of PLC is discussed.