Prevention of core cell damage in isolated islets of Langerhans by low temperature preconditioning

AIM: To study the core cell damage in isolated islets of Langerhans and its prevention by low temperature preconditioning (26 ℃).METHODS: Islets were cultured at 37 ℃ for 7-14 d after isolation, and then at 26 ℃ for 2, 4 and 7 d before additional culture at 37 ℃ for another 7 d. Core cell damage in the isolated islets was monitored by video-microscopy and analyzed quantitatively by use of a computer-assisted image analysis system. The analysis included daily measurement of the diameter and the area of the isolated islets and the area of the core cell damage that developed in those islets over time during culture. Histology and TdT-mediated dUTP-biotin nick end labeling (TUNEL) assay were used to characterize the cell damage and to monitor islet function.RESULTS: Microscopic analysis showed that during the 7 to 14 d of culture at 37 ℃, core cell damage occurred in the larger islets with diameters ＞200 μm, which included both necrotic and apoptotic cell death. Low temperature (26 ℃) culture could prevent core cell damage of isolated islets. The 7-d culture procedure at 26 ℃ could inhibit most of the core cell (excluding diameters＞300 μm) damages when the islets were re-warmed at 37 ℃.CONCLUSION: Our results indicate that core cell damage within isolated islets of Langerhans correlates with the size of islets. Low temperature (26 ℃) culture can prevent core cell damage in isolated islets, and successfully precondition these islets for incubation at 37 ℃. These novel findings may help to understand the pathophysiology of early loss of islet tissue after transplantation, and may provide a new strategy to improve graft function in the clinical setting of islet transplantation.

Type-Ⅱ Core/Shell Nanowire Heterostructures and Their Photovoltaic Applications

Nanowire-based photovoltaic devices have the advantages over planar devices in light absorption and charge transport and collection.Recently,a new strategy relying on type-Ⅱ band alignment has been proposed to facilitate efficient charge separation in core/shell nanowire solar cells.This paper reviews the type-Ⅱ heterojunction solar cells based on core/shell nanowire arrays,and specifically focuses on the progress of theoretical design and fabrication of type-Ⅱ Zn O/Zn Se core/shell nanowire-based solar cells.A strong photoresponse associated with the type-Ⅱ interfacial transition exhibits a threshold of 1.6 e V,which demonstrates the feasibility and great potential for exploring all-inorganic versions of type-Ⅱ heterojunction solar cells using wide bandgap semiconductors.Future prospects in this area are also outlooked.

Single-cell transcriptome reveals core cell populations and androgen-RXFP2 axis involved in deer antler full regeneration

Deer antlers constitute a unique mammalian model for the study of both organ formation in postnatal life and annual full regeneration.Previous studies revealed that these events are achieved through the proliferation and differentiation of antlerogenic periosteum(AP)cells and pedicle periosteum(PP)cells,respectively.As the cells resident in the AP and the PP possess stem cell attributes,both antler generation and regeneration are stem cell-based processes.However,the cell composition of each tissue type and molecular events underlying antler development remain poorly characterized.Here,we took the approach of single-cell RNA sequencing(scRNA-Seq)and identified eight cell types(mainly THY1^(+)cells,progenitor cells,and osteochondroblasts)and three core subclusters of the THY1^(+)cells(SC2,SC3,and SC4).Endothelial and mural cells each are heterogeneous at transcriptional level.It was the proliferation of progenitor,mural,and endothelial cells in the activated antler-lineage-specific tissues that drove the rapid formation of the antler.We detected the differences in the initial differentiation process between antler generation and regeneration using pseudotime trajectory analysis.These may be due to the difference in the degree of stemness of the AP-THY1+and PP-THY1^(+)cells.We further found that androgen-RXFP2 axis may be involved in triggering initial antler full regeneration.Fully deciphering the cell composition for these antler tissue types will open up new avenues for elucidating the mechanism underlying antler full renewal in specific and regenerative medicine in general.