[Screening and culture of rat spermatogonial stem cells].

AIM: To establish a system of screening and culture of rat spermatogonial stem cells (SSCs). METHODS: We prepared the rat testis cells using the improved two-step enzymatic digestion, and then isolated the rat SSCs by the differential adherence selection method. The highly enriched SSCs were cultured in the serum-free culture medium of DMEM/F12 supplemented with glial cell line-derived neurotrophic factor (GDNF), soluble GFRα1 and basic fibroblast growth factor (bFGF) and on rat embryonic fibroblast (REF)feeder layer. The activity of stem cells was examined morphologically and by RT-PCR and immunocytochemical analysis for the SSCs marker gene expressions. RESULTS: The modified two-step enzymatic digestion could effectively isolate the rat testis cells, and from the isolated testis cells, rat SSCs could be successfully purified by the improved method of differential adherence selection. After over-20-day culture of the rat SSCs in serum-free medium, big colonies of SSCs were observed, and the activity of SSCs got affirmed by the positive expressions of SSCs marker genes. CONCLUSION: The system of screening and culture of rat SSCs has been established, which provide a basis for the long-term culture of rat and other animal SSCs.

Benzimidazolium 2-(2,4-dichloro-phen-oxy)acetate monohydrate.

In the crystal of the title hydrated mol-ecular salt, C(7)H(7)N(2) (+)·C(8)H(5)Cl(2)O(3)·H(2)O, the components inter-act by way of N-H⋯O and O-H⋯O hydrogen bonds, leading to chains propagating in [100].

Ammonium 2-(2,4-dichloro-phen-oxy)acetate hemihydrate.

The title compound, NH(4) (+)·C(8)H(7)Cl(2)O(6) (-)·0.5H(2)O, was prepared by the reaction of 2-(2,4-dichloro-phen-oxy)-acetic acid and ammonia in water at 367 K. The mol-ecular structure and packing are stabilized by N-H⋯O and O-H⋯O inter-molecular hydrogen-bond inter-actions.

[Comparison of preparing two polylactide nanoparticles loaded lipophilic anti-cancer herb drug by nanoprecipitation method].

This paper introduced an experimental study of polylacticacid (PLA) nanoparticles of lipophilic anti-cancer herb drug using a precipitation method. Cucurbitacins (Cu) and Curcuminoids (Cur) were selected to be model drugs. They had similar solubility but their incorporation effects were significantly different: the average drug entrapment ratio, the average drug loading and the average drug recovery were 38.53%, 2.21% and 27.02% respectively; while those of Cur-PLA-NP were 94.36%, 14.35% and 91.23% respectively. To analyse the reason, drug incorporation process was investigated. By measuring solvent evaporation rate, ratio of drug PLA precipitates, drug distribution in system and entrapping ratio at different time of preparation, we found the difference of precipitation velocity of drug was the main reason. We also concluded that not all lipophilic drug can be well entrapped into PLA nanoparticle by nanoprecipitation method. The drug incorporation depended on the interations among drug, PLA and organic solvents, in addition to the solubility of the drug.

[The preparation of the polylacticacid nanoparticles of cucurbitacin and their drug loading].

This paper introduced an experimental study of the preparation of polylacticacid (PLA) nanoparticles of cucurbitacin (CuC) using a precipitation method. The residual acetone, ratio of CuC PLA precipitates, and the relationships between the ratios of two precipitates and drug incorporation rates were measured. It appeared that the nanoparticles with 60% of PLA incorporated with 5.5% of CuC were formed when acetone was injected into the aqueous phase. As the acetone gradually evaporated, drug incorporation/encapsulation continued, with most of CuC (about 70%) formed new crystalline cores and suspended in the form of microcrystals in the medium, resulting a suspension containing both nanoparticles and microcrystals. We also concluded that this system may not necessarily be suitable for all lipophilic drugs to be prepared to PLA nanoparticles with good incorporation rate. The drug incorporation depended on the interactions among drug, PLA, and organic solvents, in addition to the solubility of the drug.