Retrospective epidemiological analysis of sparganosis in mainland China from 1959 to 2012.

In this study, epidemiological factors of sparganosis cases reported in mainland China from 1959 to December 2012 were analysed. A total of 1061 valid cases were distributed throughout most of the provinces of mainland China, with most cases occurring in Southern and Eastern China. The average age of patients was 29 years (range 0-80 years). Modes of transmission to humans were via contact (54·6%), mainly by application of frog meat as a poultice, foodborne (33·8%), mainly through ingesting frogs or snakes, and waterborne (11·5%) through drinking raw water. The tissue/organs involved were subcutaneous/muscle (43·1%), eyes (31·0%), central nervous system (CNS) (17·9%), urogenital system (3·9%) and visceral organs (3·2%). Obvious differences existed in main risk factors for different areas. Close correlation was found between tissue/organs and risk factors. Main modes of transmission changed during the past decades, from contact (83·8% pre-1979) to foodborne (63·9% post-2000). The tissue/organs involved also changed at the same time. Cases involving eyes fell from 50·0% pre-1979 to 8·3% post-2000, and cases involving CNS increased from 0% pre-1979 to 47·8% post-2000. These results illustrate that China is one of the main epidemic countries of sparganosis in the world. Consumption of frog/snake meat was the main risk factor, although application of frog flesh as a poultice was the main risk factor before 2000. Sparganosis has become one of the neglected but important foodborne/waterborne parasitic diseases in mainland China.

Inducible expression of calreticulin-N58 in Pichia pastoris by high density cell culture.

Calreticulin-N58 (CRT-N58), an active fragment of calreticulin with anti-angiogenesis activity, was expressed in P. pastoris by high density cell culture. Calreticulin-N58 DNA was synthesized by PCR and cloned to plasmid pPIC9 K resulting in the plasmid pPIC9 K-crt-N58 which was then transformed into P. pastoris GS115. The fermentation was carried out in a 50 l bioreactor with 20 l modified growth medium recommended by Invitrogen at 30°C. The cells were first grown in glycerol-PTM4 trace salts for 24 h. When the cell density was grown to A(600) = 135, methanol-PTM4 trace salts was added to induce the expression of calreticulin-N58. During the fermentation, dissolved oxygen level was maintained at 20-30%, pH was controlled at 5 by adding 7 M NH(4)OH. After 52 h of induction, the yield of secreted calreticulin-N58 was 70 mg/l and biomass growth was 293 as measured by absorption of 600 nm. The secreted calreticulin-N58 was purified to a purity of 100% by the use of SP-Sepharose FF ion-exchange chromatography (Pharmacia Biotech. NJ, USA) and desalted with ultrafiltration device (Millipore, Bedford, MA, USA). The recombinant calreticulin-N58 induced endothelial cell apoptosis and inhibited the angiogenesis on the CAM.