ABSTRACT
Three different kinds of sinomenine in situ liquid crystal were prepared for different prescriptions, to investigate the rheological properties before and after in situ treatment and evaluate its feasibility for embolization. Rheological experiments were carried out with cone plate fixtures. Both the steady-state rheological and non-steady-state rheological properties of in-situ gels and the swelling gels were studied and compared. Steady-state rheological study results showed that all the three liquid embolic agents were non-newtonian fluid before and after in situ treatment, which would become less ropy when they were pressed with shear stress; their viscosities differed by 2-5 orders of magnitude. It had a yield value of about 10 Pa before in situ treatment and about 4 500 Pa after in situ treatment. All the six systems had thixotropy while their dynamic viscosities were not influenced by the shear rate, all less than 0.3 Pa·s before in situ treatment more than 1 Pa·s after in situ treatment, differing by an order of magnitude. The results of temperature sweeping showed a slight decrease with a steady rate in viscosity within the range of 10-50 °C, differing by 3-4 orders of magnitude. The results of unsteady rheology showed that there was no obvious linear viscoelastic region in the three kinds of agents, indicating the properties of liquid. After in situ treatment, their linear viscoelastic range γ<1% (No.3 was 5%), and their elastic modulus G' was larger than the viscous modulus G", indicating the properties of solid. Frequency scanning results showed that for the systems at low frequencies, G">G', system viscosity in a dominant position; while at high frequencies, G'>G", system elasticity in a dominant position. The results of compound viscosity test also proved that the liquid embolic agent in situ can form a cubic liquid crystal (the structure of No. 3 was destroyed after in situ treatment). The DHR-2 rheometer was used to investigate the rheological properties of in situ gels with three different prescriptions. The method is simple and the result is reliable, which can provide more theoretical reference for the evaluation and practical application of the product.
ABSTRACT
The purpose of this study was to investigate the effects of chloroquine diphosphate on the proliferation and apoptosis of human leukemic K562 cells, and to elucidate its possible mechanism of activity. The inhibitory effect of chloroquine diphosphate with different concentrations on K562 cell proliferation was detected by MTT method. Apoptosis was measured by flow cytometry (FCM); morphological analysis of apoptosis was performed after staining with propidium iodide (PI) under fluorescence microscope; cell apoptosis was assessed by the DNA ladder shown agarose gel electrophoresis. After treatment with chloroquine diphosphate, K562 cells were stained by Rhodamine 123 to detect changes in mitochondrial transmembrane potential (DeltaPsim) by FCM. The results showed that the cell viability decreased in dose-dependent manner, following chloroquine diphosphate treatment at different concentrations (1.5625, 3.125, 6.25, 12.5, 25, 50 and 100 micromol/L) for 24, 48 and 72 hours. By FCM analysis, the significant increases of sub-G(1) were observed. DNA ladder was detected and apoptotic nuclei were observed. DeltaPsim decreased in K562 cells after chloroquine diphosphate treatment. It is concluded that the chloroquine diphosphate can inhibit the proliferation of K562 cells and induce cell apoptosis, which may relate to down-regulation of mitochondrial transmembrane potential (DeltaPsim).