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Objective To investigate the filtration roles of microporous membranes with different pore sizes in the tumor cells with different diameters,and effects on the filtered cells.Methods Three kinds of tumor cells with different cell diameters and same concentrations,including Jurkat,K562 and A549,were filtered by the polycarbonate microporous membranes with different pore sizes such as 1,3,5,8 and 10 μm,respectively,and their filtration rates were determined.The diameters of three kinds of tumor cells before and after filtration,and the fixed K562 cells with formaldehyde,were measured by an optical microscope.The activity of the filtered K562 cells were detected by the trypan blue staining.After the filtered K562 cells were re-cultured,their proliferation activity was analyzed by the growth curve.Results Jurkat,K562 and A549 cells couldn't pass the filter membrane with 1 μm of pore size.The filtration rates of three kinds of tumor cells passing the fliter membranes with 3 μm,5 μm,8 μm and 10 μm of pore sizes increased in turn.The survival rate of K562 cells filtered by 3 μm of pore size of membrane was 92.0％,and the proliferation acticity of re-cultured K562 cells was still strong.The filtration rate of the fixed K562 cells with formaldehyde was significantly decreased,and the average diameter of the filtered cells had no obvious change.Conclusion The living cells are able to pass the membranes with the pore sizes less than their diameters.The living cells passed the filter membranes may still maintain their growth and proliferation activity.However,the fixation of formaldehyde may significantly reduce the number of cells passed the membrane.
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Objective:To find the reasons for the low dissolution of clarithromycin tablets and study the interference from filter film adsorption at various time points to explore the appropriate processing approach for dissolution solution of clarithromycin tablets. Meth-ods:Clarithromycin tablets from two different manufacturers were used. The dissolution solution was prepared according to Japanese Orange Book. The dissolution was determined after different processing and the adsorption rate of the filter film was calculated. Re-sults:Totally 14 kinds of filter films were tested with different adsorption for clarithromycin, and the adsorption rate of some kinds of filter films exceeded the prescribed limit. Conclusion:The absorption rate of filter films for clarithromycin can be decreased by boiling the films and using American membranes. The interference from filter film adsorption can be reduced and inhibited by rejecting the first filtrate above 5ml or centrifuging dissolution solution.
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PURPOSE: Major drawbacks of conventional bone marrow stromal cells (BSCs) transplantation method are mainly caused by direct transplanted cell to host cell interactions. We hypothesized that separation of the transplanted cells by a microporous membrane might inhibit most of the potential adverse effects and induce superior effect. The purpose of the study is to determine the optimal condition of the microporous membrane. METHODS: First, BSCs were placed in polyethylene terephthalate (PET) transwell inserts with 3, 8, or 12 micrometer pore size, and cultured in 24 well culture plates. After 5 days, bottoms of the plates were observed for presence of attached BSCs in monolayer and cell numbers were evaluated. Second, BSCs were placed PET, polycarbonate (PCT), and mixed cellulose esters (MCE) transwell inserts with 3 and 8 micrometer pore size, and cultured in 24 well culture plates. After 3 days, the supernatants of the media left in culture plate were analyzed for collagen, vascular endothelial growth factor (VEGF), platelet derived growth factor BB (PDGF-BB), and basic fibroblast growth factor (bFGF). Third, BSCs were placed in 15% and 70% of the PET membrane with 3 micrometer pore size. All the experimental conditions and methods were same as the second study. RESULTS: The optimal pore sizes to prevent BSC leakage were 3 micrometer and 8 micrometer. The amounts of type I collagen and three growth factors tested did not show significant differences among PET, PCT, and MCE groups. However, the collagen, VEGF, and bFGF levels were much higher in the high (70%) density group than in the low (15%) density group. CONCLUSION: This study revealed that the optimal pore size of membrane to prevent direct BSC to recipient cell contact is in between 3 micrometer and 8 micrometer. Membrane materials and pore sizes do not influence the collagen and growth factor passage through the membrane. The most striking factor for collagen and growth factor transport is pore density of the membrane.