Hollow mesoporous organosilica nanotheranostics incorporating formimidoyltransferase cyclodeaminase (FTCD) plasmids for magnetic resonance imaging and tetrahydrofolate metabolism fission on hepatocellular carcinoma.

The formimidoyltransferase cyclodeaminase (FTCD) gene encodes an enzyme required for the catabolism of histidine and tetrahydrofolate (THF). Previous studies showed that FTCD plays a role as a tumour suppressor gene in hepatocellular carcinoma (HCC). It is unknown whether the restoration of functional FTCD may exhibit an anti-tumour effect on HCC. This study constructed a delivery system based on hollow mesoporous organosilica nanotheranostics (HMON) capable of efficiently loading Mn ions and FTCD plasmids. This study showed that the Mn-doped and FTCD-loaded nanoparticles (HMON@Mn-PEI@FTCD) could efficiently induce the expression of FTCD and achieve enhanced magnetic resonance imaging. In vitro results demonstrated that the upregulation of FTCD induced by HMON@Mn-PEI@FTCD nanoparticles dramatically reduced intracellular THF levels, inhibited of NADPH/NADP+ and GSH/GSSG ratios, and induced reactive oxygen species generation and mitochondrial oxidative stress. As a result, cytochrome c release increased with the opening of the mitochondrial permeability transition pore, which finally activated the caspase-dependent cell apoptosis pathway. Therefore, our designed HMON@Mn-PEI@FTCD could induce apoptosis by activating the mitochondria-mediated apoptosis signalling pathway, and finally significantly suppressed the proliferation of HCC both in vitro and in vivo, which provides an effective strategy for the treatment of HCC.

Polybrominated diphenyl ethers in surface soils from e-waste recycling areas and industrial areas in South China: concentration levels, congener profile, and inventory.

Polybrominated diphenyl ethers (PBDEs) were determined in 60 surface soils from two e-waste recycling sites (Qingyuan and Guiyu, China) and their surrounding areas to assess the extent and influence of PBDEs from e-waste recycling sites on the surrounding areas. A total of 32 surface soils from industrial areas in South China were also investigated for comparison. The mean concentrations of total PBDEs in the e-waste recycling sites of Guiyu and Qingyuan were 2,909 and 3,230 ng/g dry weight, respectively, whereas the PBDE concentrations decreased dramatically (1-2 orders of magnitude) with increasing distance from the recycling site, suggesting that the e-waste recycling activities were the major source of PBDEs in the surrounding areas. Decabromodiphenyl ethers accounted for 77.0 to 85.8% of total PBDEs in e-waste recycling areas, whereas it accounted for 90.2% in industrial areas. Principal component analysis showed that the major source of PBDEs in e-waste recycling areas were a combination of penta-, octa-, and deca-BDE commercial formulations, whereas deca-BDE commercial formulations were the major source of PBDE congeners in industrial areas. The inventories of PBDEs gave preliminary estimates of 6.22 tons and 13.4 tons for the e-waste recycling areas and industrial areas. The results suggested that significantly higher PBDEs in the e-waste recycling sites have already affected surrounding areas negatively within a relatively large distance. Because of the environmental persistence, bioaccumulation, and toxicity of PBDEs, improving the recycling techniques employed at such facilities and developing e-waste management policies are necessary.

[Investigation on the chiral recognition site of enantioselective separation of ofloxacin by capillary zone electrophoresis using vancomycin as a chiral selector].

The chiral recognition site of the macrocyclic antibiotic vancomycin, used as a chiral selector in capillary electrophoresis (CE), was studied with ofloxacin, antofloxacin (a new fluoroquinolone antibiotic under development) and R-antofloxacin, as well as with norvancomycin. Enantioselectivity of vancomycin and norvancomycin was compared. The influence of vancomycin concentration, pH of buffer, and separation voltage in CE were examined in order to investigate interactions between enantiomers and vancomycin. Furthermore, interactions of chiral selectors and enantiomers were calculated by molecular mechanics method with Chem 3D software. The result indicates that both vancomycin and norvancomycin have two domains in 3D structure, and the domain I of vancomycin was considered to be the chiral recognition site of ofloxacin. The degree of interaction between vancomycin and ofloxacin is determined as follows: hydrogen bond occurring with carboxylic group at C-6 of ofloxacin and hydroxyl group of sugar part of vancomycin, the matching degree of molecular sizes of ofloxacin with the pocket in domain I of vancomycin and the hydrophobic interaction between methyl group at C-10 of piperidine group of ofloxacin and N-methyl leucine of vancomycin.

[Analysis of the response factors of different quinolones detected by evaporative light-scattering detector].

AIM: To analyze the response factors of different quinolone antibiotics detected by evaporative light-scattering detector (ELSD). METHODS: The response factors of five different quinolones (enoxacin, levofloxacin, ciprofloxacin, lomefloxacin and gatifloxacin) detected by ELSD were determined by using a YMC-Pack ODS-AM cloumn (150 mm x 4.6 mm ID, 5 microns) as analytical column and 0.5% triethylamine (adjusting pH 2.5 with trifluoroacetic acid)-acetonitrile (48:12) as mobile phase at a flow rate of 0.6 mL.min-1, the temperature of the drift tube was set at 117 degrees C, and the flow of carrier gas at 3.0 L.min-1. Detector responses (A) and the amount of injection of each substance (m) were fitted to the logarithmic regression: log A = b log m + log a. RESULTS: The linear regression equation obtained were: enoxacin: Y = 1.0799X + 2.7611, r2 = 0.9996; levofloxacin: Y = 1.0913X + 2.7235, r2 = 0.9997; ciprofloxacin: Y = 1.0828X + 2.7523, r2 = 0.9994; lomefloxacin: Y = 1.0891X + 2.7391, r2 = 0.9993; gatifloxacin: Y = 1.0878X + 2.7392, r2 = 0.9995. The differences between them were negligible. CONCLUSION: Different quinolones can give the same responses with ELSD detection. So, the HPLC-ELSD methods can be applied to the determination of new substances by using another substance as reference.