ABSTRACT
Although high-efficiency targeted delivery is investigated for years, the efficiency of tumor targeting seems still a hard core to smash. To overcome this problem, we design a three-step delivery strategy based on streptavidin-biotin interaction with the help of c(RGDfK), magnetic fields and lasers. The ultrasmall superparamagnetic iron oxide nanoparticles (USIONPs) modified with c(RGDfK) and biotin are delivered at step 1, followed by streptavidin and the doxorubicin (Dox) loaded nanosystems conjugated with biotin at steps 2 and 3, respectively. The delivery systems were proved to be efficient on A549 cells. The co-localization of signal for each step revealed the targeting mechanism. The external magnetic field could further amplify the endocytosis of USPIONs based on c(RGDfK), and magnify the uptake distinctions among different test groups. Based on photoacoustic imaging, laser-heating treatment could enhance the permeability of tumor venous blood vessels and change the insufficient blood flow in cancer. Then, it was noticed that only three-step delivery with laser-heating and magnetic fields realized the highest tumor distribution of nanosystem. Finally, the magnetism/laser-auxiliary cascaded delivery exhibited the best antitumor efficacy. Generally, this study demonstrated the necessity of combining physical, biological and chemical means of targeting.
ABSTRACT
Objective:To study on the levels of CXCL8 and its receptors (CXCR1 and CXCR2) in peripheral blood neutrophils of the patients with chronic hepatitis B.Methods:The neutrophils were isolated and purified by neutrophil isolation medium,and the loads of HBV-DNA in neutrophils were detected by PCR,and the levels of HBeAg in serum were measured by ELISA.The patients were divided into different groups according to the detective results so that the expressions of CXCL8 and its receptors ( CXCR1,CXCR2) in neutrophils were detected by the methods of streptavidin-biotin complex ( SABC ) immunocytochemistry stain.Results:The data of SABC immunocytochemical stain showed that the positive color of CXCL8 was mainly located in the cytoplasm of PMNs.However,the most positive color of CXCR1and CXCR2 was mainly expressed in the cytoplasm and cell membrane.Interestingly,the deeper immune coloring of CXCL8 and CXCR1, and relatively shallow immune coloring of CXCR2 were explored in the group with positive of HBeAg.The similar detective results also had been found in the cases with positive of HBV DNA in neutrophils.Compared with the normal control group,the levels of CXCL8 and CXCR1 in the patients were significantly increased ( P0.05).Conclusion:After neutrophils occult infected by HBV,not only the secretion of CXCL8 can be promoted, but also the expression of CXCR1 will be further increased.The data of immunohistochemical staining have been shown that the color degree of CXCL8 and its receptors ( CXCR1, CXCR2 ) are positive correlation to the level of HBeAg and the loads of HBV DNA.More PMNs can be chemotactic attraction to lesion so as to participate in the local inflammatory injury and tissue repair via the interactive pathway of the high expression of CXCR1 on surface of neutrophils with CXCL8.
ABSTRACT
The sensitive and specific immunoradiometric assay is described for human proinsulin and its intermediate peptides (65-66 split and 32-33 split proinsulin). We developed a monoclonal antibody-based two-site immunoradiometric assay with use of streptavidin-biotin labeling. The detection limits of the assays lie in the range of 0.5-2.0 pM. In the proinsulin assay proinsulin cross-reacted 66% with 65-66 split proinsulin but not with insulin or 32-33 split proinsulin. In the assay of 65-66 split proinsulin it does not cross-react with insulin, proinsulin or 32-33 split proinsulin. In the 32-33 split proinsulin assay it cross-reacted 84% with proinsulin and 60% with 65-66 split proinsulin. The precision (C.V.) of the assays was less than 15% over the various concentration. The mean concentrations of insulin, proinsulin, 65-66 split proinsulin and 32-33 proinsulin in eight young male subjects in the fasting state were (pM +/- S.E.M.) 20 +/- 3.6, 2.3 +/- 0.3, undetectable (less than 1.0) and 2.1 +/- 0.7 and at the maximum reached during an oral glucose tolerance test, 150 +/- 26, 9.9 +/- 1.4, 3.8 +/- 0.6 and 19.7 +/- 6.0 respectively.