[A sampling survey on the distribution of Oncomelania snails in Zhejiang Province].

OBJECTIVE: To find out current distribution of Oncomelania snails and Schistosoma infection in snails in Zhejiang Province, so as to improve the project of schistosomiasis control. METHODS: Investigation spots were selected by stratified cluster sampling method, 100 villages of 34 counties were selected from 7106 villages of 55 counties as survey spots. Synchronously systematic and environmental samplings were used for the survey. Snails were dissected to determine the infection status and spots with sham snails were set to assess the quality of the survey. RESULTS: The result showed that snails were found in 223 strips, 1572 frames and 73,300 m2 area in 32 villages of 21 counties. Snails were found in an area covering 72,640 m2 in 29 villages of 18 counties in hilly region, which accounted for 99.1% of total snail habitats. The significantly larger area with snails was revealed in hilly region than that in water network region (t = 3.04, P < 0.01). 1st, 2nd strata occupied 71,680 m2 snail area, which accounted for 97.8% of total snail area, much higher than that in the 3rd stratum (t = 3.71 , P < 0.01). Snail habitats in the irrigation ditches and canals accounted for 62.6% of total snail area, significantly higher than that of farmland (t = 3.02, P < 0.01). No snails were found infected among 7892 living snails by dissection. The theory value of snail area in Zhejiang Province was 1,361,940 m2. CONCLUSION: It is estimated that the snail-ridden area is about 1,500,000-2,000,000 m2 in the Province, mostly found in the villages of hilly region with a record of snail habitats during the recent 4 years and the primary environment of the snail areas were ditches and canals. No infected snails were found from the survey.

Liposomes modified with P-aminophenyl-α-D-mannopyranoside: a carrier for targeting cerebral functional regions in mice.

Targeting of intracerebral functional regions has been limited by the inability to transport drugs across the blood-brain barrier (BBB) and by poor accumulation in these regions. To overcome these hurdles, liposomes modified with P-aminophenyl-α-d-mannopyranoside (MAN) were used as a fluorescent dye carrier through the BBB and used the specific distribution of liposomes (LIP) modified with MAN (MAN-LIP) to target various functional regions of the brain. An in vitro BBB model was established to evaluate the transendothelial ability of MAN-LIP, and liposomes uptake by C6 glioma cells was analyzed by flow cytometry and live cell imaging. Liposome targeting was evaluated using in vivo and ex vivo imaging. After MAN-LIP administration, the transendothelial ability and the delivery of fluorescent dye to the brain significantly increased. MAN-LIP concentrated in the cortex at 4 h, shifting distribution to the cerebellum and brainstem at 12 h. The fluorescence intensity in the hippocampus and pontine nuclei remained high and stable over a period of 12 h. The results demonstrate that MAN-LIP is able to enhance cellular uptake in vitro and also promotes penetration through the BBB and accumulation in the brain with a distinct spatio-temporal pattern.

HP-ß-CD-PLGA nanoparticles improve the penetration and bioavailability of puerarin and enhance the therapeutic effects on brain ischemia-reperfusion injury in rats.

It is well known that puerarin attenuates ischemia-reperfusion injury and promotes function recovery of ischemic region. However, due to its reverse physiochemical properties, puerarin does not easily cross the blood-brain barrier. The aim of the present study is to create puerarin nanoparticles which increase and prolong the puerarin concentration in the brain. Using emulsion solvent evaporation techniques, we designed puerarin-loaded poly(D,L-lactic-co-glycolic acid) nanoparticles. Hydroxypropyl beta cyclodextrin (HP-ß-CD) was used to increase the solubility of puerarin and gelatin to enhance viscosity of inner water phase, which improved puerarin entrapment. The drug release kinetics and nanoparticle degradation in phosphate buffered saline (PBS) were analyzed by electronic microscopy and high-performance liquid chromatography. Computerized tomography scans were used to detect the infarction volume and electroencephalogram (EEG) was recorded to estimate the recovery of brain function. The results showed that the combined HP-ß-CD and gelatin significantly improved the entrapment efficiency. The infarction volume was significantly decreased on days 3 and 7 after the administration of puerarin nanoparticles compared with that of control and pure puerarin. EEG was also significantly improved. Puerarin nanoparticles are potentially applicable for the brain injury induced by ischemic-reperfusion.