RESUMO
Human umbilical cord mesenchymal stem cells (HUCMSCs) are applied for disease therapy as a new type of drug in many countries. Their effects are not only presented by live cells, but also apoptotic bodies or cell fragments of dead cells. Therefore, it is meaningful to determine the multiple fates of HUCMSCs in vivo. Although various probes combining different imaging modalities have been developed to label and trace transplanted HUCMSCs in vivo, the status of the cells (live, dead, or apoptotic) was not distinguished, and a thorough understanding of the multiple fates of HUCMSCs after transplantation in vivo is lacking. Therefore, a magnetic resonance (MR)/near infrared fluorescent (NIRF)/bioluminescence (BI) multi-modality imaging strategy was developed. Iron oxide nanoparticles (IONPs) were assembled into 100 nm nanoparticles using epigallocatechin gallate as a chemical linker to increase the MR signal and reduce the exocytosis of IONPs for direct cell labeling and longitudinal MR imaging tracking. Fluorescent probes for apoptosis (DEVD-Cy-OH) were also loaded in the above assemblies to monitor the cell status. Meanwhile, the cell surface was labeled with the fluorescent dye Cy7 via bioorthogonal reactions to visualize the NIRF signal. Luciferase was lentivirally transfected into live cells to generate bioluminescence. Such labeling did not affect either the viability, proliferation, migration, differentiation characteristics of HUCMSCs or their therapeutic effects on acute liver injury mice in vivo. The in vivo fates of HUCMSCs were monitored via MR/NIRF/BI multi-modality imaging in acute liver injury mice. Although MR and Cy7 signals aggregated in injured liver for 7 days, the BI signals persisted for less than 24 hours. There was an increase in DEVD-Cy-OH signals in the injured liver, but they were almost at the basal level. That means that HUCMSCs survive in mice for a short time, and the dead form of HUCMSCs accumulated in a large quantity and sustained for a long time, which might contribute to their therapeutic effect.
RESUMO
BACKGROUND: China is continuing to witness rising numbers of migrants (e.g., individuals migrating from rural to urban areas), and alongside this are the social restrictions and institutional barriers migrants face. Such restrictions and barriers are a consequence of the long-standing urban-rural dualist system and can create a sense of relative deprivation among migrants-that is, dissatisfaction when migrants perceive they are at a disadvantage compared with local residents of an area. OBJECTIVE AND METHOD: Based on Pierre Bourdieu's field theory, the current study used data from the 2017 Chinese General Social Survey (N = 1849) to explore the mechanism through which migrants' home ownership or non-ownership in the migration process affects their sense of relative deprivation. To do so, a ranked regression and parallel multiple mediation model were developed. Additionally, a heterogeneity analysis was conducted to account for the region in which migrants lived and their age. RESULTS: The results revealed that home ownership significantly reduced migrants' relative deprivation. Moreover, the perception of economic and symbolic capital was found to play a role in the effects of wealth and class, respectively. From the heterogeneity analysis, the direct and mediated effects of housing attributes on migrants' relative deprivation were more significant for migrants in the eastern versus central and western regions of China, as well as among new-versus older-generation migrants. CONCLUSION: To improve the feasibility of home ownership among migrants and, thus, alleviate their relative deprivation in the inflow area, relevant policies (e.g., improving the housing system pathway) should be developed and implemented.
