[Anti-tumor effect and its related mechanisms of cinobufotalin combined with cisplatin on H22 liver cancer mice].

In order to observe the anti-tumor effect of cinobufotalin on H22 liver cancer mice and to explore its regulatory mechanism, 50 Kunming mice were subcutaneously inoculated with H22 intraperitoneal passage cells under the armpit to establish H22 hepatocellular carcinoma model. They were then randomly divided into model group, cinobufotalin low dose group, cinobufotalin high dose group, cisplatin group and cisplatin+cinobufotalin group, which received 0.01% ethanol solution, 1 mg·kg~(-1) cinobufotalin, 5 mg·kg~(-1) cinobufotalin, 5 mg·kg~(-1) cisplatin, 5 mg·kg~(-1)cisplatin + 5 mg·kg~(-1) cinobufotalin respectively for 10 days. The general condition of mice during the intervention was observed, and the inhibition rate, tumor mass, thymus index, histopathological changes of the tumors, apoptotic rate of the tumors, the expressions of phosphatidylinositol 3-kinase(PI3 K), protein kinase B(Akt), apoptosis related gene(Fas), Fas ligand(FasL) mRNA and protein phosphorylated Akt(pAkt) protein in the tumors of each group were compared. The results showed that during the modeling period, the mice showed a decline in food intake, dark fur, poor mental status, and gradually worsened over time. The mental status of mice in each intervention group was improved gradually, especially in the cisplatin+cinobufotalin group. As compared with the model group, the tumor mass of each intervention group was lower(P<0.05). As compared with the cinobufotalin low dose group, the tumor mass was lower and inhibition rate was higher in the cinobufotalin high dose group, cisplatin group and cisplatin+cinobufotalin group(P<0.05). As compared with the cinobufotalin high dose group and the cisplatin group, the tumor mass was lower and the inhibition rate was higher in cisplatin+cinobufotalin group(P<0.05). As compared with the model group, the thymus index was higher in cinobufotalin high dose group and cisplatin + cinobufotalin group, while was lower in cisplatin group(P<0.05). As compared with the cinobufotalin low dose group, the thymus index was higher in the cinobufotalin high dose group and lower in the cisplatin group(P<0.05). As compared with the cinobufotalin high dose group, the thymus index was lower in cisplatin group(P<0.05). As compared with cisplatin group, the thymus index was higher in cisplatin+cinobufotalin group(P<0.05). Pathological staining showed that a large number of heterogeneous cells and mitotic phenomena were observed in the model group. Cell fragments and neutrophils were observed in the tumor tissues of the intervention groups, showing diffuse necrosis, and the diffuse necrosis was more obvious in the cisplatin+cinobufotalin group. As compared with the model group, the apoptotic rate of the tumors and the relative expressions of Fas mRNA and protein were higher in the intervention groups, while the relative expressions of PI3 K, FasL mRNA and protein and the relative expression of pAkt protein were lower in the intervention groups(P<0.05). As compared with the cinobufotalin low dose group, the apoptotic rate of the tumors and relative expression of Fas and protein were higher in the cinobufotalin high dose group, cisplatin group and cisplatin+cinobufotalin group, while the relative expressions of PI3 K, FasL mRNA and protein and pAkt protein were lower(P<0.05). As compared with the cinobufotalin high dose group and the cisplatin group, apoptotic rate of the tumors and the relative expression of Fas mRNA and protein were higher in the cisplatin+cinobufotalin group, while the relative expressions of PI3 K, FasL mRNA and protein and pAkt protein were lower in the cisplatin+cinobufotalin group(P<0.05). In summary, cinobufotalin has significant anti-tumor effect on H22 liver cancer mice, and can enhance the immune function of mice and synergistically enhance the effect of chemotherapy. Its mechanism may be associated with regulating PI3 K/Akt/Fas/FasL signaling pathway related genes and protein expression.

The Mechanism of Computed Tomography-Guided 125I Particle in Treating Lung Cancer.

BACKGROUND The incidence of malignant tumor has gradually increased. How to improve the survival and quality of life of patients who lose the opportunity for surgery or who are unwilling to receive surgery remains an obstacle. At present, 125I particle interstitial implant therapy has been applied in a variety of treatments of tumors. However, the mechanism of computed tomography (CT)-guided 125I particle therapy in lung cancer has not been fully elucidated. MATERIAL AND METHODS A total of 42 patients with advanced non-small cell lung cancer were retrospectively analyzed between January 2013 and December 2013, including 19 patients who received CT-guided 125I particle therapy and 23 patients who received chemotherapy. Curative effect and adverse reactions at 6 months and 12 months were compared and analyzed. A rabbit lung cancer VX2 model was treated by 125I particle implantation therapy under CT guidance. The change in tumor volume was detected. Tumor cell apoptosis was tested by flow cytometry. Bcl-2 and Bax expression were determined by real-time polymerase chain reaction (PCR) and Western blot. RESULTS 125I particle therapy obviously reduced tumor volume after 6 months and 12 months. It showed significantly higher efficiency (57.9%, 57.9%) and control (78.9%, 73.7%) than the rates of efficiency and control in the chemotherapy group (P<0.05). 125I particle implantation therapy markedly suppressed rabbit VX2 transplanted tumor cell proliferation, promoted tumor regression, induced tumor cell apoptosis, reduced Bcl-2 expression, and upregulated Bax expression level (P<0.05). CONCLUSIONS CT-guided 125I particle implantation therapy can inhibit tumor proliferation and growth by regulating the expression of apoptosis-related genes and proteins, which is a promising approach in lung cancer treatment.

Modular integration of electronics and microfluidic systems using flexible printed circuit boards.

Microfluidic systems offer an attractive alternative to conventional wet chemical methods with benefits including reduced sample and reagent volumes, shorter reaction times, high-throughput, automation, and low cost. However, most present microfluidic systems rely on external means to analyze reaction products. This substantially adds to the size, complexity, and cost of the overall system. Electronic detection based on sub-millimetre size integrated circuits (ICs) has been demonstrated for a wide range of targets including nucleic and amino acids, but deployment of this technology to date has been limited due to the lack of a flexible process to integrate these chips within microfluidic devices. This paper presents a modular and inexpensive process to integrate ICs with microfluidic systems based on standard printed circuit board (PCB) technology to assemble the independently designed microfluidic and electronic components. The integrated system can accommodate multiple chips of different sizes bonded to glass or PDMS microfluidic systems. Since IC chips and flex PCB manufacturing and assembly are industry standards with low cost, the integrated system is economical for both laboratory and point-of-care settings.

Dual frequency dielectrophoresis with interdigitated sidewall electrodes for microfluidic flow-through separation of beads and cells.

This paper presents a novel design and separation strategy for lateral flow-through separation of cells/particles in microfluidics by dual frequency coupled dielectrophoresis (DEP) forces enabled by vertical interdigitated electrodes embedded in the channel sidewalls. Unlike field-flow-fractionation-DEP separations in microfluidics, which utilize planar electrodes on the microchannel floor to generate a DEP force to balance the gravitational force and separate objects at different height locations, lateral separation is enabled by sidewall interdigitated electrodes that are used to generate non-uniform electric fields and balanced DEP forces along the width of the microchannel. In the current design, two separate AC electric fields are applied to two sets of independent interdigitated electrode arrays fabricated in the sidewalls of the microchannel to generate differential DEP forces that act on the cells/particles flowing through. Individual particles (cells or beads) will experience DEP forces differently due to the difference in their dielectric properties. The balance of the differential DEP forces from the electrode arrays will position dissimilar particles at distinct equilibrium planes across the width of the channel. When coupled with fluid flow, this results in lateral separation along the width of the microchannel and the separated particles can thus be automatically directed into branched channel outlets leading to different reservoirs for downstream processing. In this paper, we present the design and analysis of lateral separation enabled by dual frequency coupled DEP, and cell/bead and cell/cell separations are demonstrated with this lateral separation strategy. With vertical interdigitated electrodes on the sidewall, the height of the microchannel can be increased without losing the electric field strength in contrast to other multiple frequency DEP devices with planar electrodes. As a result, populations of cells can be separated simultaneously instead of one by one to enable high-throughput sorting microfluidic devices.

Unique dielectric properties distinguish stem cells and their differentiated progeny.

The relatively new field of stem cell biology is hampered by a lack of sufficient means to accurately determine the phenotype of cells. Cell-type-specific markers, such as cell surface proteins used for flow cytometry or fluorescence-activated cell sorting, are limited and often recognize multiple members of a stem cell lineage. We sought to develop a complementary approach that would be less dependent on the identification of particular markers for the subpopulations of cells and would instead measure their overall character. We tested whether a microfluidic system using dielectrophoresis (DEP), which induces a frequency-dependent dipole in cells, would be useful for characterizing stem cells and their differentiated progeny. We found that populations of mouse neural stem/precursor cells (NSPCs), differentiated neurons, and differentiated astrocytes had different dielectric properties revealed by DEP. By isolating NSPCs from developmental ages at which they are more likely to generate neurons, or astrocytes, we were able to show that a shift in dielectric property reflecting their fate bias precedes detectable marker expression in these cells and identifies specific progenitor populations. In addition, experimental data and mathematical modeling suggest that DEP curve parameters can indicate cell heterogeneity in mixed cultures. These findings provide evidence for a whole cell property that reflects stem cell fate bias and establish DEP as a tool with unique capabilities for interrogating, characterizing, and sorting stem cells.

Dielectrophoresis switching with vertical sidewall electrodes for microfluidic flow cytometry.

A novel dielectrophoresis switching with vertical electrodes in the sidewall of microchannels for multiplexed switching of objects has been designed, fabricated and tested. With appropriate electrode design, lateral DEP force can be generated so that one can dynamically position particulates along the width of the channel. A set of interdigitated electrodes in the sidewall of the microchannels is used for the generation of non-uniform electrical fields to generate negative DEP forces that repel beads/cells from the sidewalls. A countering DEP force is generated from another set of electrodes patterned on the opposing sidewall. These lateral negative DEP forces can be adjusted by the voltage and frequency applied. By manipulating the coupled DEP forces, the particles flowing through the microchannel can be positioned at different equilibrium points along the width direction and continue to flow into different outlet channels. Experimental results for switching biological cells and polystyrene microbeads to multiple outlets (up to 5) have been achieved. This novel particle switching technique can be integrated with other particle detection components to enable microfluidic flow cytometry systems.

Fungi use efficient algorithms for the exploration of microfluidic networks.

Fungi, in particular, basidiomycetous fungi, are very successful in colonizing microconfined mazelike networks (for example, soil, wood, leaf litter, plant and animal tissues), a fact suggesting that they may be efficient solving agents of geometrical problems. We therefore evaluated the growth behavior and optimality of fungal space-searching algorithms in microfluidic mazes and networks. First, we found that fungal growth behavior was indeed strongly modulated by the geometry of microconfinement. Second, the fungus used a complex growth and space-searching strategy comprising two algorithmic subsets: 1) long-range directional memory of individual hyphae and 2) inducement of branching by physical obstruction. Third, stochastic simulations using experimentally measured parameters showed that this strategy maximizes both survival and biomass homogeneity in microconfined networks and produces optimal results only when both algorithms are synergistically used. This study suggests that even simple microorganisms have developed adequate strategies to solve nontrivial geometrical problems.