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Microplastics refer to plastic particles with a diameter of less than 5 mm. Because of their wide distribution in the environment, it has gradually become one of the environmental hot issues of global concern in recent years. Microplastics are characterized by small particle size and strong adsorption. Existing studies have confirmed the biotoxic effects of microplastics in marine organisms and in experimental animals, suggesting their potential harm to human health. However, there have been few studies on the effects of microplastics on human health, and the research results have been inconsistent. Therefore, by summarizing the recent domestic and foreign studies about human exposure to microplastics as well as their potential effects on human body, this paper provides ideas and theoretical basis for further exploring the effects of microplastics on human health and related mechanisms.
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Innate immune system rapidly detects and responds to viruses at the early stage of viral infection. However,the mechanisms by which the immune system recognizes and eliminates them have not been fully clarified so far. Studies have shown that receptors are the primary tool for cell recognition and detection of viruses, and cyclic GMP-AMP synthase(cGAS)is one of the newly found DNA recognition receptors. cGAS transmits the signal to the downstream protein called STING(stimulator of interferon genes)and mediates the production of type I interferon(IFN-I),thereby to initiates the antiviral immunity of cells. This review briefly introduces the mechanism of the cGAS-STING signaling pathway, in order to provide a theoretical basis for the research and development of new antiviral drugs.
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<p><b>OBJECTIVE</b>To investigate the effect of bortezomib in inducing apoptosis in imatinib-resistant K562 (K562R) cells and its possible mechanism.</p><p><b>METHODS</b>K562 cells were cultured in gradient concentrations of imatinib for several months to generate imatinib-resistant K562 cells. The viability of K562R cells treated with bortezomib was measured using CCK-8 cell proliferation assay, and the cell apoptosis was analyzed by flow cytometry with annexin V/PI dual staining. Western blotting was used to detect the protein expressions of Mcl-1,Bcl-2 and Bcr/Abl.</p><p><b>RESULTS</b>K562R cell line was successfully established, which showed 31.8 folds of imatinib resistance compared with the na?ve cells. Bortezomib treatment produced dose- and time-dependent inhibitory effect on the proliferation of both K562 cells and K562R cells and dose-dependently induced apoptosis in K562R cells. Combination of bortezomib with imatinib significantly enhanced the apoptosis of the cells. Western blotting showed that bortezomib treatment dose-dependently decreased the protein levels of both Mcl-1and Bcr/Abl in K562R cells without affecting bcl-2 protein expression.</p><p><b>CONCLUSION</b>Bortezomib can inhibit the proliferation of K562R cells and induce cell apoptosis possibly by down-regulating Mcl-1 and Bcr/Abl expression and enhancing Mcl-1 cleavage.</p>
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To study the tissue distribution of galactosyl daphnoretin liposomes in rats. At the dose of 10 mg•kg⁻¹, daphnoretin solution, daphnoretin liposomes, and galactosyl daphnoretin liposomes were administered to healthy SD rats via tail vein injection. The blood and tissue of heart, liver, spleen, lung, kidney, stomach, small intestine, brain and thymus were collected at 5, 15, 30, 45, 60, 120, 240, 360 min after administration. The concentrations of daphnoretin in plasma and tissue samples were determined by HPLC. The results showed that galactosyl daphnoretin liposomes group had the highest concentration of daphnoretin in liver of unit weight at different time points; and at all of the time points, the target index DTI values of galactosyl daphnoretin liposomes to liver were greater than that of daphnoretin liposomes. Compared with daphnoretin solution, the AUC0-6 and Cmax of galactosyl daphnoretin liposomes in liver were 2.23, 5.22 times, respectively. This indicated that galactosyl daphnoretin liposomes can be concentrated at liver, with a significant liver targeting effect.
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Objective To discuss the effects of different drying methods on composition and antioxidative activities of the volatile oil fromCymbopogon citrates; To optimize the best drying method for Cymbopogon citrates. MethodsCymbopogon citrates was dried by drying in the sun, drying in the shade and oven drying at 40℃. Volatile oil was extracted by steam distillation. Chemical constituents in the volatile oil were analyzed by GC-MS and the antioxidative activities were determined by ferric reducing antioxidant power (FRAP method).Results Extraction rate of the volatile oil fromCymbopogon citratesunder the environment of freshness, sun drying, shade drying and oven drying at 40℃ were 0.25%, 1.21%, 1.19% and 1.17%, respectively; after dried by different methods, main constituents and antioxidative activities of the volatile oil fromCymbopogon citrates were basically same. Conclusion Different drying methods have little influence on composition and antioxidative activities of the volatile oil fromCymbopogon citrates. Oven drying at 40℃ was the best way to dryCymbopogon citrates.
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Objective To study the content of volatile oil from old leaves, tender leaves, fallen leaves and seeds of cinnamomum camphora tree in Hunan, China. To prepare and identify the volatile oil of its β-cycoldextrin inclusion compound. Methods The volatile oil was extracted by water-steam distillation. With inclusion rate as the index, trituration method, saturated water solution method and ultrasound method were compared. The optimum conditions were investigated by the orthogonal test. The inclusion compound was identified by thin-layer chromatography (TLC), ultraviolet visible spectrum (UV-Vis) and differential scanning calorimetry (DSC). Results From June to July, the average content of volatile oil extracted from old leaves, tender leaves, fallen leaves and seeds were 1.58%, 1.52%, 0.84% and 1.39%, respectively. The optimum preparation conditions were as follows:the ratio of β-cyclodextrin and volatile oil was 10∶1, the adding water was 4 times and inclusing time was 2 h. Before and after inclusion, the spectrum of TLC and UV-Vis of volatile oil showed no obvious change. The DSC of inclusion compound,β-cycoldextrin, volatile oil and the mixture had significant differences. Conclusion The amount of the volatile oil from old leaves is higher. The optimized condition of inclusion is stable and reasonable.