Experimental study of controlled release microencapsulated Salmonella typhi capsular polysaccharide vaccines immunized mice / 生物医学工程学杂志

Salmonella Typhi capsular polysaccharide vaccines were encapsulated in the Micro-particles made from polyethylene glycol-poly-DL-lactide (PELA). BALB/c mouse were divided into three groups with 20 mice in each. Mouse were immunized respectively with controlled release microencapsulated Salmonella Typhi capsular polysaccharide vaccines and Salmonella Typhi capsular polysaccharide vaccines by oral and subcutaneous administration. The mice blood and salvia were collected at the 2nd, 4th and 8th weeks respectively for the titrating of IgG and sIgA antibodies by RIA. At the 8th week, live typhoid bacteria were injected into the immunized mice for the calculation of the rate of immunization protection. The IgG titers of the controlled release microencapsulated Salmonella Typhi capsular polysaccharide vaccines group were higher than those of the other groups(P < 0.05). The IgA titers of the low groups of controlled release microencapsulated Salmonella Typhi capsular polysaccharide vaccines (oral and subcutaneous) were higher than those of the group of Salmonella Typhi capsular polysaccharide vaccines (P < 0.05). The immunization protection rates of the three groups were 40%, 100% and 60% respectively. The controlled release microencapsulated Salmonella Typhi capsular polysaccharide vaccines possess the advantages of releasing slowly in vivo and persisting long time immunogenicity.

Experimental research on degradation and biocompatibility of super-high-molecular-weight poly-DL-lactic acid / 华西口腔医学杂志

<p><b>OBJECTIVE</b>The super-high-molecular-weight poly-DL-lactic acid (PDLLA), with the molecular weight of 900 kD, is a newly emerging biomaterial and potentially used in the therapy of bone fracture because of its excellent mechanical property. However the biocompatibility of this material has not been reported so far, therefore this experiment was designed to examine whether the super-high-molecular-weight PDLLA was harmful to creatures, when it was implanted in the body of animals for a long period.</p><p><b>METHODS</b>The material was prepared in small cuboids, with the size of 1.0 mm x 1.5 mm x 2.0 mm, and these blocks were implanted into the masseteric space of SD rats and, the activity of the SD-rats was monitored continuously. The animals were sacrificed in the 3rd, 6th, 9th, 12th months after the operation and, the specimens were taken out from the animals. The examination included anatomical, pathological and haematological methods. The data were analyzed with SPSS 8.0.</p><p><b>RESULTS</b>The wound healed well after the operation. Super-high-molecular-weight PDLLA degraded 6 months after the implantation. In the 3rd month after the operation, a thin fiber membrane around the materials was formed. In the 6th month, the membrane was much thinner than that in the 3rd month and completely disappeared in the 9th month. The pathological examination showed that slightly inflammatory reaction appeared in the tissue around these blocks in the 3rd month, but the inflammatory reactions were gradually remitted in the following 6th, 9th and 12th months. Further, the haematological examination did not show any abnormity during the 12-month observation period.</p><p><b>CONCLUSION</b>The super-high-molecular-weight PDLLA can be degrade when it is implanted into the body of creatures, which proves its good biocompatibility.</p>