总姜黄素脂质体的包封率和体外释药测定

目的:研究总姜黄素脂质体的包封率测定方法,初步考察其体外释放规律。方法:用乙醇注入法制备了总姜黄素脂质体,葡聚糖凝胶 G-50柱分离方法测定脂质体的包封率,并用溶出度第三法考察脂质体的体外释放过程。分析柱为岛津 C_(18)色谱柱(150 mm×4.6 mm,5μm),乙腈-水-冰醋酸(45:55:2)为流动相,流速1mL·min~(-1),检测波长430nm。结果:总姜黄素脂质体的平均包封率为64.4%,体外释放符合一室模型。结论:该方法简便、易操作,可作为总姜黄素脂质体包封率和体外释药的研究。     

萘普生缓释微囊的制备及其体外释药研究

目的 对以壳聚糖和海藻酸钠为囊材,通过复凝聚法将萘普生微囊化的制备工艺和体外释药进行研究.方法 以微囊的药物包封率为制备工艺优化指标,得出成囊的最佳制备工艺条件.结果 最佳工艺条件为:搅拌速度500 r·min-1,pH4.0,壳聚糖浓度3%,反应温度50℃.结论 以最佳制备工艺条件制备了可生物相容,自然降解无毒的载药微囊,重现性好,工艺稳定,同时体外溶出实验表明,该微囊具有较好的缓释作用.     

口服高分子微球疫苗的制备研究

 目的：研制口服靶向长效的包载抗原蛋白的疫苗微球。方法：以可生物降解高分子聚-D，L-乳酸-聚乙二醇(PLA-PEG)为基质材料。采用复合乳液溶剂蒸发技术包载外膜蛋白(OMP)及人血清白蛋白(HSA)，制备出粒径小于2 μm的微球。考察了制备工艺对微球粒径及蛋白含量的影响。结果：采用适当配比的聚乙烯醇(PVA)水溶液为分散介质，可得到期望粒径的PLA-PEG微球。对抗原蛋白的包裹量可达1%左右，并视蛋白性质而定。表面活性剂可改善微球对蛋白的包裹条件。结论：可生物降解的PLA-PEG能对抗原蛋白进行有效包裹，并制得粒径小于2 μm的微球。     

甘草酸二铵脂质体的制备及其性质的研究

目的:研究甘草酸二铵阳离子脂质体的制备方法和脂质体的性质。方法:采用均匀设计筛选最佳处方,逆相蒸发法制备甘草酸二铵脂质体;葡聚糖凝胶柱法测定其包封率;用透射电镜观察脂质体的外观形态,马尔文测定仪测定脂质体的粒径和Zeta电位;并用溶出度第3法考察了脂质体的释放规律。结果:制得脂质体的包封率约为(56±1．54)%(n=3);脂质体的形态为粒径均匀的球形或近球形,粒径为(183±9)nm(n=3),Zeta电位为(22．8±6)mV(n=3);脂质体的体外释药符合Higuchi方程;具有较好的稳定性。结论:采用逆相蒸发法,添加十八胺可制得具有较高包封率及稳定性的甘草酸二铵阳离子脂质体,制得脂质体的体外释放具有缓释特点。     

Delivering polyphenols for healthy ageing

There is a growing demand for delivery of antioxidants through functional foods with the concomitant challenge of protecting their bioactivity during food processing and subsequent passage through the gastrointestinal tract. This study focuses on the retention of antioxidant activity of polyphenolic antioxidants after encapsulation/spray-drying. The polyphenolic compounds present in grape-seed extract (GSE), apple polyphenol extract (APE) and olive-leaf extract (OLE) were analysed by chromatographic methods. Catechin, epicatechin and gallic acid were identified in GSE and APE. Oleorupein is the major compound found in OLE. Total polyphenol content was found to be the highest in APE followed by GSE and OLE. These extracts were encapsulated using protein-lipid emulsions and subsequently spray-dried. Optical microscopy and particle size distribution analysis indicated the sphericity and uniform size distribution pattern of the dry particles. Radical scavenging activity studies demonstrated significant retention of antioxidant activity after the encapsulation and spray-drying process.     

Neuroprotective effects of vascular endothelial growth factor (VEGF) upon dopaminergic neurons in a rat model of Parkinson's disease

Vascular endothelial growth factor (VEGF) has previously been shown to display neuroprotective effects following ischemia, suggesting that VEGF may potentially be applied as a neuroprotective agent for the treatment of other neurological diseases. In this study, we investigated the neuroprotective capacity of VEGF in a model of Parkinson's disease. VEGF was found to be neuroprotective against cell death of primary E14 murine ventral mesencephalic neurons induced by 6-hydroxydopamine (6-OHDA) treatment in vitro. Further, rats receiving a continuous infusion of VEGF into the striatum via encapsulated hVEGF-secreting cells (baby hamster kidney-VEGF) displayed a significant decrease in amphetamine-induced rotational behavior and a significant preservation of tyrosine hydroxylase-positive neurons and fibers compared with control animals. VEGF likely functions via direct mechanisms by signaling through the neuropilin receptor expressed upon dopaminergic neurons in response to 6-OHDA treatment. Further, VEGF is likely to promote neuroprotection indirectly by activating the proliferation of glia and by promoting angiogenesis. Our results support a potential neuroprotective role for VEGF in the treatment of Parkinson's disease.     

Continuous interleukin-6 application in vivo via macroencapsulation of interleukin-6-expressing COS-7 cells induces massive gliosis

The inflammatory cytokine interleukin-6 (IL-6) was found in senile plaques of Alzheimer's patients and might be involved in the pathology of Parkinson's disease and multiple sclerosis. Interestingly, an astocytosis is also found in these neurodegenerative disorders. To evaluate the direct effects of IL-6 in vivo on glial cells, we created a new in vivo model. IL-6 and mock-transfected (control group) COS-7 cells were encapsulated in a poly-acryl-nitril membrane for implantation into the rat striatum. Afterward, the host immune reaction to the membrane without encapsulated cells and the biological action of IL-6-producing capsules was evaluated. Animals with an implanted membrane without cells showed a moderate astrocytosis 5 days after the operation. Furthermore, microglia and T-cells could be detected and after 30 days the astrocytosis decreased to a small layer around the membrane. In comparison to the control group, which received a sham operation, our results demonstrate that the response of glial cells is caused by the mechanical damage of the surgical procedure itself rather than due to the introduced membrane material. In contrast, we found a massive proliferation and activation of astrocytes and microglia after 10 days by IL-6-secreting capsules, indicating that IL-6 is involved in the induction of gliosis. Control animals that received encapsulated mock-transfected COS-7 cells showed only a weak response. These data point to an involvement of IL-6 in the proliferation and activation of glial cells as seen in neurodegenerative disorders.     

Characterization of two distinct lipomas: a comparative analysis from surgical perspective

Background: Lipomas are common benign soft tissue tumors that are well-circumscribed and encapsulated. However, adipose masses that are not demarcated from the surrounding fat are often encountered. Two distinct types of lipomas were analyzed from surgical perspective.

Methods: Thirty patients were enrolled after lipoma excision and diagnosed with either encapsulated (n?=?20) or non-encapsulated lipoma (n?=?10). Comparison of clinical variables, histologic analyses and characterization of the lipoma adipose-derived stem cells (ASCs) between the two lipomas were performed.

Results: Non-encapsulated lipomas were associated with older age at operation, larger tumor and increased seroma formation. The density of lymphatic vessels and gene expressions related to lymphatic vessel, inflammation and proliferation were increased in non-encapsulated lipoma. ASCs of non-encapsulated lipoma showed enhanced proliferation when cultured with serum.

Conclusions: Non-encapsulated lipomas and their ASCs showed distinct lymphatic histology and cellular response. These findings elucidated the pathogenesis and pathophysiology of lipomas.