Electromagnetic characteristics of antisymmetric toroidal dipole array of plasmonic metasurfaces.

An antisymmetric toroidal dipole array of plasmonic metasurfaces, whose unit cell consisted of a pair of physically connected asymmetric split-ring resonators, is presented in this study. Moreover, a new paradigm was established to control toroidal electric dipole properties. Toroidal electric dipoles and electric and magnetic hybrid pseudo-anapole states are excited owing to imperfect and perfect destructive interference, respectively, which leads to the spatial separation of the electric and magnetic fields and a distinct asymmetric Fano line shape in the transmission spectrum. The imperfect destructive interference was further modified by adjusting the relative position between the even and odd layers of the metasurfaces. The scattered power of the toroidal electric dipole is tuned continuously and linearly, which enables the tailoring of the electromagnetic response. The displacement sensitivity is approximately 0.13 GHz/mm over the range 0-8 mm. The modulation depth of the scattered power of the toroidal electric dipole can reach 740%, realising a toroidal electric-dipole-to-electric-dipole transition. The proposed plasmonic metasurfaces provide a platform to efficiently control near-field enhancement, far-field radiation, and electric-magnetic separation and find potential applications in frequency-selective surfaces, sensors, filters, spectroscopic tests, and many other areas.

Curative effect of the recent photofrin photodynamic adjuvant treatment on young patients with advanced colorectal cancer.

Advanced colorectal cancer has a high mortality rate and conventional treatments have poor therapeutic effects. The aim of the present study was to analyze the recent curative effect and adverse reaction of photofrin photodynamic adjuvant treatment on young patients with advanced colorectal cancer. A total of 23 patients with advanced colorectal cancer who had accepted semiconductor laser photodynamic adjuvant treatment were selected as the observation group. In addition, 30 patients who had accepted concurrent radiotherapy and chemotherapy during the same period served as the control group. The observation group received photofrin (2 mg/kg) intravenously in 100 ml of 5% glucose, followed by the introduction of the endoscopic optical fiber to deliver laser radiation with an intensity of 630 nm wavelength pulse power. After 2 days, necrotic tissues were removed and irradiation of the original or new tumor lesions was performed and necrotic tissues were removed. The total effective rate and survival time was higher and the length of hospital stay was shorter in the observation group in comparison with the control group. The differences were statistically significant (P<0.05). The number of patients in the control and observation groups with symptoms of hematochezia, change in bowel habit, intestinal stimulation and incomplete intestinal obstruction were reduced. Additionally, the reduced ratio of the observation group was significantly increased in comparison with the control group (P<0.05). The adverse reaction rate of the observation group was lower than that of the control group and this difference was also statistically significant (P<0.05). In conclusion, use of photodynamic treatment for young patients with advanced colorectal cancer can effectively improve the clinical symptoms and reduce complications.

Protective effects of monosialotetrahexosylganglioside sodium on H2O2-induced human vascular endothelial cells.

Monosialotetrahexosylganglioside sodium (GM1) is widely used in the treatment of central and peripheral neurological injuries. In addition to its neuroprotective activity, GM1 exerts protective effects on brain microvascular endothelial cells, although the mechanisms underlying these effects remain unclear. The aim of the present study was to clarify the protective effects and underlying mechanisms of GM1 on human umbilical vein endothelial cells (HUVECs). In this study, hydrogen peroxide (H2O2) was applied to induce the HUVEC injury. HUVECs in a logarithmic growth phase were divided into five groups, namely the control, H2O2-treated, 10-mg/l GM1, 5-mg/l GM1 and 1-mg/l GM1 groups. In all the groups, cell proliferation was detected using a Cell Counting Kit-8 assay, a flow cytometric method was applied to analyze the cell cycle and nuclear factor (NF)-κB expression was evaluated using immunofluorescence analysis. In addition, the protein expression levels of NF-κB, phosphatidylinositol 3-kinase (PI3K) and glycogen synthase kinase (GSK)-3 were detected via western blot analysis. The results indicated that GM1 exerted significant protective effects on H2O2-injured cells by increasing the ratio of cells in the S/G2 phase. Furthermore, western blot analysis revealed that PI3K expression levels were markedly increased after 24 h, as a result of the GM1 treatment, while the expression of both GSK-3 markedly decreased. In addition, the ratio of nuclear-to-cytoplasmic NF-κB expression increased in the GM1-treated cells. In summary, GM1 exhibited marked protective effects on the HUVECs, possibly due to the ability of GM1 in maintaining the integrity of the endothelium and increasing the proportion of cells undergoing mitosis, a process in which the PI3K/GSK-3 and NF-κB pathways are crucially involved.

Role of cellular cytoskeleton in epithelial-mesenchymal transition process during cancer progression.

Currently, cancer metastases remain a major clinical problem that highlights the importance of recognition of the metastatic process in cancer diagnosis and treatment. A critical process associated with the metastasis process is the transformation of epithelial cells toward the motile mesenchymal state, a process called epithelial-mesenchymal transition (EMT). Increasing evidence suggests the crucial role of the cytoskeleton in the EMT process. The cytoskeleton is composed of the actin cytoskeleton, the microtubule network and the intermediate filaments that provide structural design and mechanical strength that is necessary for the EMT. The dynamic reorganization of the actin cytoskeleton is a prerequisite for the morphology, migration and invasion of cancer cells. The microtubule network is the cytoskeleton that provides the driving force during cell migration. Intermediate filaments are significantly rearranged, typically switching from cytokeratin-rich to vimentin-rich networks during the EMT process, accompanied by a greatly enhanced cell motility capacity. In the present review, the recent novel insights into the different cytoskeleton underlying EMT are summarized. There are numerous advances in our understanding of the fundamental role of the cytoskeleton in cancer cell invasion and migration.

Co-culture with endometrial stromal cells enhances the differentiation of human embryonic stem cells into endometrium-like cells.

In vitro differentiation of human embryonic stem cells (hESCs) into endometrium-like cells may provide a useful tool for clinical treatment. The aim of the present study was to investigate the differentiation potential of hESCs into endometrium-like cells using three methods, which included induction by feeder cells, co-culture with endometrial stromal cells and induction with embryoid bodies. Following differentiation, the majority of cells positively expressed cytokeratin and epithelial cell adhesion molecule (EPCAM). Factors associated with endometrium cell function, namely the estrogen and progesterone receptors (ER and PR), were also detected. At day 21 following the induction of differentiation, the expression levels of cytokeratin, EPCAM, ER and PR were significantly increased in the co-culture method group, as compared with the other two methods. Furthermore, these cells became decidualized in response to progesterone and prolactin. In addition, the number of cytokeratin-positive or EPCAM-positive cells significantly increased following the induction of differentiation using the co-culture method, as compared with the other two methods. The mRNA expression levels of Wnt members that are associated with endometrial development were subsequently examined, and Wnt5a was found to be significantly upregulated in the differentiated cells induced by feeder cells and co-culture with endometrial stromal cells; however, Wnt4 and Wnt7a expression levels were unaffected. Additionally, the mRNA expression levels of Wnt5a in the differentiated cells co-cultured with endometrial stromal cells were higher when compared with those induced by feeder cells. In conclusion, the present findings indicated that the co-culture system is the optimal protocol for the induction of hESC differentiation into endometrium-like cells, and Wnt5a signaling may be involved in this process.

Advances in the application of nanotechnology in the diagnosis and treatment of gastrointestinal tumors.

Nanotechnology has broad application prospects in the diagnosis and treatment of cancer. Integrating chemistry, engineering, biology and medicine, nanotechnology is a multidisciplinary research field. Nanoscale imaging technology significantly improves the precision and accuracy of tumor diagnosis. Nanocarriers are able to significantly improve the accuracy of dose and targeted drug delivery and reduce the toxic side effects. This review focuses on the emerging roles of these innovative technologies in gastrointestinal cancer diagnostics and therapeutics. Although several problems and barriers are hampering the development of nanodevices, the potential for nanotechnologies to function as multimodal nanotheranostic agents will likely pave the way for the fight against gastrointestinal cancer.