Thermodynamic Analysis of Myelin Basic Protein Adsorbed on Liquid Crystalline Dioleoylphosphatidylcholine Monolayer.

To investigate the stability and dynamic characteristics of monolayer adsorbed on unsaturated lipid dioleoylphosphatidylcholine (DOPC) with varying concentrations of myelin basic protein (MBP), the system is studied by applying Langmuir technique and making atomic force microscope (AFM) observation, which is based on the mass conservation equation analysis method referred to in the thermodynamics theory. As indicated by surface pressure-mean molecular area (π - A) and surface pressure-adsorption time (π - T) isotherms, the physical properties of monolayer derived from the interaction of varying concentrations of MBP with liquid crystalline unsaturated lipid DOPC molecules were qualitatively studied. As revealed by surface morphology analysis with AFM, the micro region was expanded as the concentration of MBP in the subphase was on the increase, suggesting that hydrophobic interactions led to the MBP insertion, thus causing accumulation of the MBP on the surface of the monolayer. Experimental results have demonstrated that the partition coefficient of the interaction between MBP and unsaturated phospholipid DOPC and the molecular area of MBP adsorbed on the monolayer film was calculated using the mass conservation equation. In addition, not only does the varying concentration of MBP in the subphase exerts significant effects on the arrangement and conformation of DOPC monolayer, it also has certain guiding significance to exploring the structural changes to biofilm supramolecular aggregates as well as the pathogenesis and treatment of related diseases.

Effects of a moderate-intensity static magnetic field and adriamycin on K562 cells.

The aim of this study was to investigate whether a moderate-intensity static magnetic field (SMF) can enhance the killing effect of adriamycin (ADM) on K562 cells, and to explore the effects of SMF combined with ADM on K562 cells. We analyzed the metabolic activity of cells, cell cycle distribution, DNA damage, change in cell ultrastructure, and P-glycoprotein (P-gp) expression after K562 cells were exposed continuously to a uniform 8.8 mT SMF for 12 h, with or without ADM. Our results showed that the SMF combined with ADM (25 ng/ml) significantly inhibited the metabolic activity of K562 cells (P < 0.05), while neither ADM nor the SMF alone affected the metabolic activity of these cells. Cell ultrastructure was altered in the SMF + ADM group. For example, cell membrane was depressed, some protuberances were observable, and vacuoles in the cytoplasm became larger. Cells were arrested at the G2/M phase and DNA damage increased after cells were treated with the SMF plus ADM. ADM also induced the P-gp expression. In contrast, in the SMF group and SMF + ADM group, the P-gp expression was decreased compared with the ADM group. Taken together, our results showed that the 8.8 mT SMF enhanced the cytotoxicity potency of ADM on K562 cells, and the decrease in P-gp expression may be one reason underlying this effect.

Studies on structure, physicochemical properties and anticancer activity of glycyrrhizic acid aniline-platinum complex compounds / 中草药

Object To investigate the structure, physicochemical properties and anticancer activity of three kind of glycyrrhizic acid aniline platinum complex compounds. Methods Using the FT IR methods, elementary analysis and X ray diffraction, the physicochemical properties of the tested drugs were determined; by means of MTT test the inhibitory effects of the drugs on human tumor cell growth were examined, with hematopoietic cell K 562 , melanoma cell LiBr and liver cancer cell 7721 as the model of anticancer activity. Results Experimental values of elemental analysis of three complex compounds tally with the theoretically calculative values. The infrared spectroscopy showed that the functional group location agreed with the structure. The X ray diffraction exhibited that this type of the compounds was monoclinic system. Conclusion The experimental results show that the anticancer activity of the test complex compounds is related to their concentration and ligands. Magnetic field treatment has significant influence on anticancer activity of this type of compounds.