FTIR Characterization of the Secondary Structure of Insulin Encapsulated within Liposome

Aim:To determine the secondary structure of insulin encapsulated within liposome.Methods:The secondary structure of native insulin,mixture of insulin with liposome(sample I) and insulin encapsulated within liposome(sample Ⅱ) were determined by FTIR(Fourier Transform Infrared) spectroscopy.Results:The secondary structure of insulin encspsulated within liposome(Ⅱ） are similar with the secondary structure of native insulin.The difference existed in the amount of α-helices (from 36% of insulin to 31% of sample Ⅱ）and β-sheet(from 48% of insulin to 51% of sample Ⅱ).The content of α-helices and β-sheet of insulin in sample I was found to be very close to that of sample Ⅱ.The results revealed that the insulin encapsulated within liposome possibly spread on the surface of liposome,without inserting into the liposome membrane.Coclusion:The secondary structure of insulin encapsulated within liposome is similar with the native insulin.     

RMP-7及其衍生物对脂质体跨血脑屏障作用的影响

目的研究RMP-7及其衍生物对脂质体跨血脑屏障的促进作用。方法测定RMP-7与DSPE-PEG-NHS偶联的物质的量比；用血脑屏障的体外模型验证其生物活性；观察脑组织切片中伊文思蓝的荧光位置和强度，测定脑组织中伊文思蓝的浓度。结果RMP-7与DSPE-PEG-NHS偶联物质的量比为1∶1；RMP-7和DSPE-PEG-RMP-7能使过氧化合物酶跨血脑屏障体外模型的转运速率增加2～3倍，修饰脂质体后能使所包封的伊文思蓝在脑中的浓度增加。结论RMP-7与DSPE-PEG-RMP-7对脂质体跨血脑屏障均有促进作用，且后者效果更好。     

Skin oxygenation after topical application of liposome-entrapped benzyl nicotinate as measured by EPR oximetry in vivo: Influence of composition and size

New and improved drug delivery systems are the important subject of much scientific research. The development of formulations that increase skin oxygenation and of methods for measuring oxygen levels in skin are important for dealing with healing processes affected by the level of oxygen. We have use EPR oximetry in vivo to compare the influence of liposomal formulations of different size and composition with that of hydrogel with respect to the action of the entrapped benzyl nicotinate (BN). Following the topical application of BN onto the skin of mice, pO₂ increase was measured by low-frequency EPR as a function of time. The effect of BN was evaluated by 3 different parameters: lag-time, time needed for maximum pO₂ increase, and overall effectiveness expressed by the area under the response-time curve. An increase in skin oxygenation was observed after BN application. The results show that the effect of BN incorporated in liposomes is achieved more rapidly than the effect from hydrophilic gel. The composition of the liposomes significantly affects the time at which BN starts to act and, to a lesser extent, the maximum increase of pO₂ in skin and the effectiveness of BN action. However, the size of the liposomes influences both the effectiveness of BN action and the time at which BN starts to act. After repeated application of liposomes, the pO₂ baseline increased and the response of the skin tissue was faster. Our results demonstrate that EPR oximetry is a useful method for evaluating oxygen changes after drug application and for following the time course of their action.     

RMP-7对两性霉素B脂质体跨血脑屏障能力的药效学研究RMP-7对两性霉素B脂质体跨血脑屏障能力的药效学研究

目的研究两性霉素B脑靶向脂质体对小鼠脑膜炎的治疗作用。方法用薄膜超声法制备两性霉素B脂质体和两性霉素B脑靶向脂质体,测定其包封率和浓度;建立小鼠的脑膜炎模型,研究了两性霉素B脂质体的疗效。结果两性霉素B脂质体的包封率为(93.3±1.8)%;脑内注射白色念珠球菌2 h使小鼠形成脑膜炎模型;将两性霉素B制成脑靶向脂质体,能显著延长脑膜炎小鼠的生存期。结论与普通两性霉素B脂质体相比,两性霉素B脑靶向脂质体能显著提高对小鼠脑膜炎的治疗作用,使小鼠的存活期延长一倍。     

两性霉素B脂质体粒度测定方法研究

目的：建立两性霉素B脂质体粒度检测方法，通过测定一组性质不同的样品，找出最佳测定方法。方法：用计算机的图像一数字处理技术结合扫描电镜、透射电镜和激光光散射粒度测定仪分别测定两性霉素B脂质体的粒度。结果：电镜法测定两性霉素B脂质体的粒度为20—100nln，平均粒径为55—75nm；激光光散射法测定两性霉素B脂质体的粒度为30—200nm，平均粒径为50—180nm。结论：激光光散射法能较好反映两性霉素B脂质体在使用时的真实粒度，且方法快速、简便，是一种较好的两性霉素B脂质体粒度测定方法。     

The effect of immunotherapy on the serum levels of eosinophil cationic protein in seasonal allergic rhinitis

The role of serum eosinophil cationic protein levels in allergic rhinitis is controversial. It is also unclear whether with immunotherapy it is possible to reduce these serum levels in allergic diseases. We studied serum eosinophil cationic protein levels in patients with cedar-induced allergic rhinitis and compared them with non-atopic controls. The second aim of this study was to elucidate whether immunotherapy is capable of decreasing the seasonal elevation in serum eosinophil cationic protein levels in seasonal allergic rhinitis. The serum eosinophil cationic protein levels of the untreated patient group were significantly higher than those of the non-atopic controls. The levels in patients who received immunotherapy for 2 yr were also significantly higher than those of the non-atopic controls. However, the levels were not different between the patients undergoing immunotherapy for over 3 yr and the non-atopic controls. The serum levels of the 31 patients treated with immunotherapy correlated with the duration of immunotherapy. In conclusion, the serum eosinophil cationic protein levels are higher in untreated patients with seasonal allergic rhinitis and this seasonal activation in circulating eosinophils decreases gradually during immunotherapy, but this inhibitory effect becomes apparent only after a number of years of immunotherapy. This prevention of seasonal eosinophil activation is one of the mechanisms responsible for the clinical effect of immunotherapy.     

Outcome of children with respiratory symptoms without objective evidence of asthma: a two-year, prospective, follow-up study

This study evaluated the outcome of 33 children with asthma-like symptoms without objective evidence of asthma, and the role of certain factors in predicting the development of clinical asthma in these children. Data on symptom histories, lung functions (flow-volume spirometry, free running test and methacholine inhalation challenge test) and atopic sensitization (skin prick tests and markers of eosinophilic inflammation) were collected twice with an interval of 2 y, and the diagnoses were re-evaluated after the follow-up period. Based on the results, it was concluded that one-third of the children with prolonged or recurrent lower airway symptoms, such as cough or wheeze, either have mild asthma or will develop asthma in the near future. Children who had a significant response [≥ 10% fall in forced expiratory volume in 1 s (FEV1)] in the free running test formed a risk group for active asthma, whereas other baseline characteristics seemed not to predict the outcome.     

Targeted Gene Transfer for Adenocarcinoma Using a Combination of Tumor-specific Antibody and Tissue-specific Promoter

We have developed a highly specific gene transfer method for adenocarcinoma using a monoclonal antibody against tumor-specific antigen coupled with a plasmid containing the carcinoembryonic antigen (CEA)-specific promoter. The chimeric CEA promoter (CC promoter), which contained an enhancer from the immediate early gene of cytomegalovirus and the CEA promoter, achieved 4- to 5-fold higher transgene expression in CEA-producing cells than the original CEA promoter while maintaining CEA specificity. Furthermore, a complex of a monoclonal antibody against Lewis Y antigen (LYA), the CC promoter-containing plasmid and cationic liposomes (DOTAP) achieved specific gene expression in CEA-producing and LYA-positive adenocarcinoma cell lines that was 200-fold more efficient than in CEA-non-producing and LYA-negative cell lines during a short in vitro incubation. This strategy may be applicable for clinical gene therapy.     

Antitumor Immunity Induction by Intracellular Hyperthermia Using Magnetite Cationic Liposomes

Induction of antitumor immunity to T-9 rat glioma by intracellular hyperthermia using functional magnetic particles was investigated. Magnetite cationic liposomes (MCLs), which have a positive surface charge, were used as heating mediators for intracellular hyperthermia. Solid T-9 glioma tissues were formed subcutaneously on both femurs of female F344 rats, and MCLs were injected via a needle only into the left solid tumors (treatment side). The rats were then divided into two groups, which received no irradiation, or irradiation for 30 min given three times at 24-h intervals with an alternating magnetic field (118 kHz, 384 Oe). On the treatment side, the tumor tissue disappeared completely in many rats exposed to the magnetic field. The tumor tissue on the opposite side also disappeared completely, even though MCLs were not injected into the right solid tumors. To examine whether a long-lasting and tumor-specific immunity could be generated, the rats that had been cured by the hyperthermia treatment were rechallenged with T-9 cells 3 months later. After a period of transient growth, all tumors disappeared. Furthermore, immuno-cytochemical assay revealed that the immune response induced by the hyperthermia treatment was mediated by both CD8⁺ and CD4⁺ T cells and accompanied by a marked augmentation of tumor-selective cytotoxic T lymphocyte activity. These results suggest that our magnetic particles are potentially effective tools for hyperthermic treatment of solid tumors, because in addition to killing of the tumor cells by heat, a host immune response is induced.