RESUMO
Type 1 Diabetes (T1D) is characterized by hyperglycemia, and caused by a lack of insulin secretion. At present there is no cure for T1D and patients are dependent on exogenous insulin for lifelong, which seriously affects their lives. Mesenchymal stem cells (MSCs) can be differentiated to ß cell-like cells to rescue the secretion of insulin and reconstruct immunotolerance to preserve the function of islet ß cells. Due to the higher proportion of children and adolescents in T1D patients, the efficacy and safety issue of the application of MSC's transplant in T1D was primarily demonstrated and identified by human clinical trials in this review. Then we clarified the mechanism of MSCs to relieve the symptom of T1D and found out that UC-MSCs have no obvious advantage over the other types of MSCs, the autologous MSCs from BM or menstrual blood with less expanded ex vivo could be the better choice for clinical application to treat with T1D through documentary analysis. Finally, we summarized the advances of MSCs with different interventions such as genetic engineering in the treatment of T1D, and demonstrated the advantages and shortage of MSCs intervened by different treatments in the transplantation, which may enhance the clinical efficacy and overcome the shortcomings in the application of MSCs to T1D in future.
RESUMO
Ab initio (MP2) and density functional theory (DFT) methods were used to examine nine isomers of the doublet BN(4) species with the 6-311 + G(d) basis set. To our knowledge, these nine structures are all first reported here. Energy analysis indicates that the C(2v) branched structure is the global minimum of potential energy surface. Research results show that the C(2v) branched, the cis-linear, the C(4v) pyramidal, and the C(S) five-membered ring structures are likely to be stable and to be observed experimentally. Among these four kinetically stable species, the last three are suitable to be used as potential precursors of HEDMs due to their high dissociation energies. However, the C(2v) bent, the trans-linear, the D(2) bicyclic, the C(2v) four-membered ring, and the C(2v) cage structures are kinetically unstable due to their low dissociation or isomerization barriers. Two synthesis pathways of the C(2v) branched isomer were located. It seems more feasible to synthesize this species by linear NBN and N(2).