Compared with other technologies, magnetic resonance cell imaging imaging technology has more prospects in the tracking of living cells because of its advantages of longer effective imaging time, observable cell dynamic migration process, high spatial and temporal resolution, and good contrast. For optimism. MRI in vivo tracking of magnetically labeled cells MRI in vivo tracking of transplanted stem cells requires the use of MRI contrast agent to magnetize the labeled cells to differentiate them from the host cells. At present, there are two main types of MRI contrast agents that label stem cells: One type is Gd3 + contrast agent, so-called paramagnetic contrast agent, which mainly produces a T1 positive contrast effect. There are not many related application reports at present, mainly because of the current MRI field strength The amount of Gd3 + needs to reach a considerable level, which is technically difficult. Of course, several studies have successfully applied Gd3 + complex into the cell through endocytosis or endocytosis and then performed MRI reports. Modo and other Gd-DTPA and gadolinium rhodamine dextran (GRID) linked with dextran polymer can provide MRI and fluorescent tissue imaging at the same time, label them immortalized mouse neural stem cells MHP36 cells and transplant into cerebral ischemia The hippocampus of rats was subjected to 4.7 T MR imaging in vitro, which confirmed that MRI can reliably distinguish transplanted cells and tracer cell migration. The other type is a superpara-magnetic iron oxide (SPIO) nanomaterial contrast agent in which a core-shell structure is formed by encapsulating Fe3O4 crystals with a dextran biopolymer, which mainly produces a strong T2 negative contrast effect. It is characterized by a small particle size, strong penetration and a relaxation rate of approximately the same. 564 International Journal of Medical Radiology 2009 Nov; 32 (6) 7 to 10 times Gd3 + under very low concentration ( nmol) can be contrasted on MRI and biodegradable, can be metabolized by cells into the normal plasma iron pool and combined with red blood cell hemoglobin or used in other metabolic processes. The above characteristics make the iron oxide-based contrast agent attract more attention, and it is an ideal magnetic resonance tracer at present. In recent years, MRI tracing of mesenchymal stem cells (MSCs) after magnetic labeling has been successfully applied to organs such as central nervous system and heart. Jendelova et al. [21] transplanted double-labeled MSCs of SPIO and BrdU into the rat cerebral cortex injury model via the contralateral cerebral hemisphere. Conventional 1.5 T MRI 28 days after surgery showed that the MSCs migrated from the injection point to the contralateral brain injury area. The distribution of specific low signals in the injured area continued until 50 days after surgery. BrdU immunohistochemical analysis showed that the transplanted MSCs differentiated into neuron cells, and the nerve function of the rats improved after surgery. Therefore, it is believed that the damaged tissue can produce rich chemical factors to promote the transplanted MSCs for targeted migration repair. Kraitchman et al. [22] used Feridex to label MSCs into the peripheral area of ​​the canine myocardial infarction model via catheter. After 8 weeks of operation, 1.5 T MRI clearly observed that a low signal line from the transplant site pointed to the myocardial infarction area, and the myocardial infarction area gradually decreased. In vivo MRI tracer magnetic marker MSCs also show important application prospects in the field of bone and joint. Mayer-Kuckuk et al. Labeled 7F2 cells and MC3T3-E1 # 4 cells with iron oxide particles bound to a fluorophore, and injected 30 μL of phosphate buffer (PBS) containing 1 × 105 magnetically labeled cells from the epiphysis of the femoral shaft to In the femoral bone marrow cavity of mice, 7 T MR in-vivo imaging showed that the specific low signal in the bone marrow cavity continued until the 9th day after surgery. Thereafter, the signal in the marrow cavity increased, indicating that the transplanted MSCs were partially lost in the femoral bone marrow cavity. Ju et al. Used magnetic iron oxide nanoparticles and poly-L-Lysine (PLL) conjugate Fe2O3-PLL to effectively label human umbilical cord blood mesenchymal stem cells and successfully performed magnetic resonance labeling Cell imaging has no obvious effect on the biological characteristics of cell viability and apoptosis. The laboratory conducted by some domestic researchers combined with the magnetic labeling of mesenchymal stem cells in the previous period, is carrying out magnetic probe labeling of liver stem cells and neural stem cells, to evaluate its effect on cell viability proliferation and apoptosis metabolism differentiation, and to evaluate different sequences of MRI Signaling characteristics of labeled cells at different concentrations, and transplantation of labeled liver stem cells in normal and liver failure rats, transplantation of neural stem cells in normal and cerebral hemisphere ischemic rats, and analysis of transplanted cells by MRI dynamic tracking The survival status of transplanted cells, summarizing the theoretical basis, technical methods and imaging performance characteristics of MRI tracking stem cells, to achieve the purpose of tracking the survival and migration of stem cells in vivo [24-27]. Although MRI tracer stem cells have shown good application prospects, magnetic markers will dilute with cell division, and there are still deficiencies in monitoring the differentiation of stem cells after transplantation [28], which needs further improvement. In summary, although the research on stem cell labeling and in vivo tracking has made important progress, there are still many problems to be solved. The various labeling methods currently used have their own advantages and disadvantages. With the development and the continuous deepening of related experiments, the current problems of various labeling and tracing methods must be solved. Among them, the technology of magnetically labeling stem cells with MRI in vivo tracing is worth looking forward to. Significant breakthroughs will be made in the use of non-invasive imaging techniques to trace stem cells in vivo.
As a multifunctional table, it can meet many
requirements of your home life. We use a mixed design of wood and metal. The
simple industrial style can be matched with different home decoration styles to
meet your home needs. At the same time, we use safety materials to make you
feel more at ease during use. And our industrial design makes the table more
sturdy and durable, which can bear more weight, while ensuring the beauty.
MODERN & STYLISH DESIGN: After a day of hard work,
while you are laying on the sofa, this piece keeps all the drinks and snacks
right by your hands. You can also use it as a convenient Laptop Stand while
relaxing on the couch.
SIMPLE SOLUTION FOR SPACES: This end table can fit right
in with your other furniture. The compact and space-saving design makes sure it
is suited for plant stand, vase holder, and coffee table.
Bedside Tables White,Lap Desk Laptop,Desk Stand Ikea,Laptop Vs Desktop Foshan Hollin Furniture Co.,Ltd , https://www.china-hollin.com
Research on stem cell labeling tracing technology