Construction and evaluation of a novel dendrimer vector-DNA vaccine for schistosomiasis japonica / 中国血吸虫病防治杂志

Objective To construct and evaluate a novel PAMAM dendrimer vector-DNA vaccine for schistosomiasis japonica.Methods Lysine was used to modify 4.0G PAMAM.and the modified product PAMAM-Lys was synthesized.Agarose gel electrophoresis was used to confirm the composite ratio of plasmid DNA and dendrimer.Micrestructure of the compound was observed by using transmission electronic microscopy,and the stability was analyzed by using electrophoresis.The viability of the cells transfected with dendrimers was evaluated by using a MTT technique in vitro.Fiftyty mice were immunized with purified plasmid pJW4303,pJW4303-Sj23 dendrimer PAMAM-Lys and compound PAMAM-Lys/pJW4303-Sj23,respectively.The specific antibodies of the mice in each group were detected to access the immunoreactivity.Results The agarese gel electrophoresis showed that when the charge ratio of the dendrimer vector and DNA was between 2 and 4,the positive and negative charges could be counteraeted completely,and the compound was blocked completely by DNA electrophoresis.The obscrvation results with transmission electronic microscopy showed that the composition of dendrimer vector and DNA caused shrink of DNA structure.Dendrimer-DNA compound had a good stability.MTT showed the modified dendrimer vector and DNA compound system produced a lower cell toxicity on 293T cell than the unmodified Ones.Thk levels of specific antibodies of the mice immunized with PAMAM-Lys/pJW4303Sj23 were significantly higher than those of the mice immunized with naked DNA vaccine(P<0.05).Conclusions The lysinemodified PAMAM-lys is an excellent vector,and has an appropriate biocompatibility.Lysine-modification can reduce the cell toxicity of PAMAM dendrimer significantly.PAMAM-Lys can enhance the immunoreactivity of DNA vacmine which merits further application in schistosomiasis DNA vaccine.

Preparation and lacrimal pharmacokinetics of eye drops of puerarin liposomes in rabbit tears / 中国中药杂志

<p><b>OBJECTIVE</b>To prepare eye drops of puerarin liposomes and investigate its lacrimal pharmacokinetics in rabbit tears.</p><p><b>METHOD</b>Puerarin liposomes were prepared by reverse phase evaporation technique. The liposomes and free puerarin were separated by SephadexG-50 chromatography and then encapsulation ratio of liposomes was determined in detail. Micromorphology of liposome particles was observed by electronic transmission microscope and the size distribution of the liposomes was analyzed by laser particle size analyzer. The concentration of puerarin in rabbit's tears was determined by HPLC after ocular administration of 50 microL puerarin liposomes while puerarin eye drops was chosen as control with the same puerarin concentration. The pharmacokinetic parameters were calculated by software program 3P97 according to one-compartment mode.</p><p><b>RESULT</b>Global liposome nanoparticles with diameter of about 195.7 nm were prepared successfully. The encapsulation ratio of puerarin in the liposomes was 48.3%. The mean residence time (MRT) value and the area under concentration (AUC) of puerarin in liposome were 3.89 and 3.06 times more than those of puerarin eye drops.</p><p><b>CONCLUSION</b>Liposomes as a drug carrier can greatly increase the concentration of puerarin in tears, enhance the pre-ocular retention time than that of eye drops.</p>

In vivo degradation and tissue compatibility of poly-L-lactide/beta-tricalcium phosphate composite rods for internal fixation of bone fractures / 生物医学工程学杂志

Abstract Poly-l-lactide/beta-tricalcium phosphate (PLLA/betaTCP) composite was obtained by combining ground beta-TCP with PLLA, and absorbable rods were prepared by injection moulding. Degradations of the rods were investigated by scanning electron microscope (SEM), mass loss, molecular weight and bending strength changes. At the beginning of in vivo degradation of the rods, the molecular weight of PLLA decreases sharply with the less mass losses of the rods. As in vivo degradation progress, the surfaces of the rods changed roughly, while micropores and fine groove were observed in the inner part of the rods. The bending strength of composite rods decreased from 151 MPa to 106 MPa after in vivo degradation of 12 weeks. Tissue test reveal that PLLA/beta-TCP composite has good tissue compatibility compared with PLLA.

Preparation of niclosamide ethanolamine nano-suspension and its molluscicidal effect / 中国血吸虫病防治杂志

Objective To prepare a novel nano-suspension of niclosamide ethanolamine and evaluate its molluscicidal effect. Methods Niclosamide ethanolamine and stabilizing agent—polyvinylpyrrolidone (PVP) were dissolved in dimethyl sulfoxide. After the solution was added into water under fast stirring, niclosamide ethanolamine was quickly precipitated to form nanoparticles and nano-suspension was obtained. The weight ratio of PVP to niclosamide ethanolamine, concentration, temperature, stirring speed on the size and distribution of the nanoparticles were investigated. The molluscicidal effect of niclosamide ethanolamine nano-suspension was measured by immersion and spray methods in the laboratory and field. Results When the weight ratio of PVP to niclosamide ethanolamine was from 1∶2 to 1∶3, the nanoparticles of the niclosamide ethanolamine had diameters about 100 nm and the nano-suspension was stable without agglomerating for more than 1 month; as the speed of the stirring increased, the nanoparticles prepared became smaller and more stable. LC50 of the nano-suspension was 0.0544 mg/L but the LC50 of wettable powder of niclosamide ethanolamine salt (WPN) was 0.1250 mg/L. In the field immersion and spray tests, the concentration of nano-suspension as only 1/5 of active content of WPN achieved the same molluscicidal effect with WPN. Conclusions The nano-suspension has higher molluscicidal effect than WPN and the novel formulation of niclosamide has more advantages than WPN, it is useful for snail control in the field.