SYNTHESIS AND CHARACTERISTICS OF A CHELATING RESIN AS AN EXTRACTANT AND CHROMOGENIC REAGENT OF HEAVY METAL IONS IN SOLID PHASE EXTRACTION

A new chelating resin （CPS-DMA-SABA） was synthesized with the chloromethylated crossqinked polystyrene porous beads （CPS） as raw materials, which were bonded with salicylidene-o-aminobenzoic acid （SABA） on the surface via a quaternary ammonium unit as a linker. The results showed that CPS-DMA-SABA would easily change into a zwitterionic chelating resin （CPS-DMA-SABZ） when washed with distilled water. CPS-DMA-SABA was characterized by elemental analysis, infrared spectra and thermo-gravimetric analysis. The ion sorption capacities of CPS-DMA-SABA were found to be 1916 μg/g for Zn2＋ withpH at 4.5, 1620μg/g for Cu2＋ with pH at 6.2, 1291 μg/g for Ni2＋ withpH at 6.6 and 780 μg/g for Cr3＋ withpH at 5.5, respectively. The experiments showed CPS-DMA-SABA also changed its color when meeting with the metal ion in the aqueous solution. As a consequence, CPS-DMA-SABA can not only be used as a solid phase extractant but also an indicator for confirming the heavy metal ion in solutions.

Antitumor immunity of low-dose cyclophosphamide:changes in T cells and cytokines TGF-beta and IL-10 in mice with colon-cancer liver metastasis

Background:The tumor immune microenvironment is one of the most important prognostic factors in liver metastasis from colorectal cancer.Low-dose cyclophosphamide(CTX)is widely believed to be involved in the modulation of the immune system.However,the underlying mechanism of low-dose CTX remains unknown.This study aimed to investigate the antitumor immunity of low-dose CTX in the treatment of colon-cancer liver metastasis.Methods:Thirty mice were randomly divided into five groups.After liver metastasis was established in colon-cancer models,mice in the treatment groups were injected with low-dose CTX(20 mg/kg)at different time points.Liver and spleen tissues were examined for T-cell markers via flow cytometry.Interleukin(IL)-10 and transforming growth factor(TGF)-b1 expression levels in liver tissues were analysed by immunohistochemistry.Serum interferon(IFN)-c and IL-10 levels were detected by enzyme-linked immunosorbent assay.An additional 20 mice were randomly allocated into two groups and the survival times were recorded.Results:The expression levels of CD4^(+)T cells,CD8^(+)T cells,and IFN-c were down-regulated,whereas those of IL-10 and TGF-b1 were up-regulated in liver metastasis from colon cancer in mice.Furthermore,the local and systemic microenvironments of the liver were altered,which led to reduced antitumor immune responses and subsequently liver metastasis.However,treatment with low-dose CTX reversed these effects.The survival times of mice treated with low-dose CTX were significantly longer than those of the other groups.Conclusions:Low-dose CTX exerts its antitumor activity by changing the systemic and local immune microenvironments and enhancing immune regulation inmice.CTX could be used as a drug to prevent and treat livermetastasis from colon cancer.