Chromatographic Determination of the Mycotoxin Patulin in 219 Chinese Tea Samples and Implications for Human Health.

Patulin (PAT) is a mycotoxin, with several acute, chronic, and cellular level toxic effects, produced by various fungi. A limit for PAT in food of has been set by authorities to guarantee food safety. Research on PAT in tea has been very limited although tea is the second largest beverage in the world. In this paper, HPLC-DAD and GC-MS methods for analysis of PAT in different tea products, such as non-fermented (green tea), partially fermented (oolong tea, white tea, yellow tea), completely fermented (black tea), and post-fermented (dark tea and Pu-erh tea) teas were developed. The methods showed good selectivity with regard to tea pigments and 5-hydroxymethylfurfural (5-HMF) and a recovery of 90-102% for PAT at a 10-100 ppb spiking level. Limit of detection (LOD) and limit of quantification (LOQ) in tea were 1.5 ng/g and 5.0 ng/g for HPLC-UV, and 0.25 ng/g and 0.83 ng/g for GC-MS. HPLC was simpler and more robust, while GC-MS showed higher sensitivity and selectivity. GC-MS was used to validate the HPLC-UV method and prove its accuracy. The PAT content of 219 Chinese tea samples was investigated. Most tea samples contained less than 10 ng/g, ten more than 10 ng/g and two more than 50 ng/g. The results imply that tea products in China are safe with regard to their PAT content. Even an extreme daily consumption of 25 g of the tea with the highest PAT content (124 ng/g), translates to an intake of only 3 µg/person/day, which is still an order of magnitude below the maximum allowed daily intake of 30 µg for an adult.

Hemodynamic changes in hepatic cancer before and after cluster electrode radio-frequency ablation.

OBJECTIVE: To evaluate the hemodynamic changes of hepatic artery (HA), portal vein (PV) and tumors in hepatic cancer patients treated by cluster electrode radio-frequency ablation with the aid of color Doppler flow imaging (CDFI). METHODS: The hemodynamic changes of HA, PV and 42 tumors in 30 cases of hepatic cancer were investigated by CDFI one week before and after cluster electrode radio-frequency ablation. RESULTS: One week after radio-frequency ablation, the velocity of HA decreased (P<0.05), but the diameter and velocity of PV unchanged. Before radio-frequency ablation, blood signals were observed in 35 cancer nodes (83.0% of all 42 nodes). After radio-frequency ablation, blood signals were reduced in 15 nodes and disappeared in 14 nodes. Early investigation implied that the decrease of blood supply was parallel with the reduction of node size. However, the outcome in case of huge nodes with double blood supply was not as promising as those small nodes. CONCLUSION: CDFI is useful to assess blood supply in ablation of hepatic cancer by using cluster electrode radio-frequency therapy.