牙鲆胚胎玻璃化冷冻技术研究

对名优经济鱼类牙鲆(Paralichthys olivaceus)胚胎的玻璃化冷冻技术方法进行了研究。筛选出了适合于牙鲆胚胎平衡和培养的基础液BS2,对牙鲆不同时期胚胎在玻璃化液VS2中的耐受能力进行了研究,随着平衡时间的延长,胚胎成活率逐渐降低,4-5对肌节期、16-20对肌节期、尾芽期表现出对玻璃化液较强的适应能力。对洗脱液的种类和浓度进行了筛选,结果显示0．125mol／L．蔗糖洗脱成活率最高。在室温(21～22％)和6℃下分别对牙鲆不同时期胚胎在VS1中的成活率进行了比较研究,结果显示出15—20对肌节期在室温下的成活率高于低温,其它时期胚胎低温下的成活率高于室温。利用VS4、VS2、VS3分别对牙鲆尾芽期、肌效应期、出膜前期胚胎进行玻璃化冷冻保存,取得了5粒成活胚,4粒孵化出膜,成活时间为14～67h。     

DMA分析添加剂对冷冻面团玻璃化转变温度的影响

以提高冷冻面团的玻璃化转变温度(Tg')为目的,研究了动态机械热分析仪(DMA)测定面团Tg'的方法,以及实验分析不同添加剂对面团Tg'的影响.结果显示:制备面团测试样品时,在其底部垫薄纸片,并将面团在DMA测试炉内冻结,然后,运用双重悬臂夹具测量面团Tg',可以准确地检测面团玻璃化转变的“峰”;测试的添加剂均能使面团的Tg'提高,按Tg'高低大小排列依次为:抗坏血酸(-25.09℃)、硬脂酰乳酸钠(SSL)(-26.32℃)、海藻糖(-27.67℃)、双乙酰酒石酸单(双)甘油酯(DATEM)(-27.69℃)、三聚磷酸钠(-28.12℃)、磷酸二氢钠(-28.26℃)、六偏磷酸钠(-29.35℃)、沙蒿籽胶(-32.54℃)、瓜尔豆胶(-35.22℃)、卵磷酯(-39.56℃).在设计冷冻面团配方时,适量的添加这些添加剂,可以提高面团的Tg',从而提高冷冻面团的储存稳定性.     

固体表面玻璃化冷冻方法降温结晶特性数值研究

固体表面玻璃化冷冻方法（SSV）及其变式在细胞冻存领域应用越来越广泛,但多基于实验和经验,缺乏仿真分析和物理机理解释,影响相关技术的通用化设计和研发效率。本文以质量分数35%的丙二醇溶液为对象,考虑冷冻过程的非等温结晶特性,建立了耦合非等温结晶源项的SSV方法传热模型,研究了预冷温度、样品体积和形状对实施SSV方法的液体温度与结晶特性的影响。结果表明：该模型可以有效揭示冷冻过程中液滴样品内部的温度及结晶度变化规律。样品结晶危险区位于远离低温表面处,且最易结晶点不一定位于液滴顶点。预冷温度越低,冷冻样品体积越小,形状越扁平,样品降温速率越快,越容易实现玻璃化冷冻。     

小鼠睾丸组织玻璃化保存的初步实验研究

对于无法取精的不育患者或患有癌症需放化疗的青春期前男孩,睾丸组织冷冻是潜在的有效保存生育力的方法.本文对小鼠块状睾丸组织的玻璃化保存方法进行了研究,运用差示扫描量热仪,对在不同体积分数保护剂中浸泡了不同时间后的小鼠块状睾丸组织进行热分析,随后对其进行玻璃化冻存,并将睾丸组织慢速冷冻保存与玻璃化冻存进行了对比.结果表明:...     

人类胚胎低温保存溶液EFSh40实现玻璃化工况条件的实验研究

实验研究了溶液EFSh40实现玻璃化的工况条件以及人类胚胎低温保存中采用双层麦管的可行性。研究结果表明,玻璃化溶液EFSh40在降温速率高于100K/min时能够玻璃化,复温速率高于200K／min时没有反玻璃化现象。本研究也实现了双层麦管中溶液EFSh40的玻璃化。采用双层麦管不但避免了潜在的污染问题,而且简化了操作程序。     

3种无卵黄型精液冷冻保护剂的比较研究

本研究对３ 种无卵黄型人类精液冷冻保护剂进行了实验比较。３ 种冷冻保护剂分别以Ｔｙｒｏｄ＇ｓ、ＢＷＷ 和Ｈａｍ Ｆ１０ 生理液为基液, 添加入甘油等成分, 不含卵黄。结果表明, 冻融后３ 组冷冻精子的活动率、膜完整率没有显著性差异 （Ｐ＞００５）。冷冻精子也具有良好的穿卵率。提示３ 种无卵黄型冷冻保护剂对精子有相似的冷冻保护效果, 可以作为人类精子库选用的冷冻保护剂。     

NMR分析冷冻面团在低温下的水份特性

运用NMR分析冷冻面团从-70℃升温到5℃过程中的水份特性,以及运用MRI图像显示了面团的解冻过程。面团中的水分可以分为两部分:半结合水,其横向弛豫时间(T2)约为10ms;深层结合水,其T2约为2ms。观察冷冻面团在升温过程中的质子信号幅度变化情况,可得出结论:半结合水在面团冻结时,一部分形成冰,另一部分转变成不可冻结水;深层结合水在面团冻结时不发生状态变化或迁移,提高面团中深层结合水的含量有利于冷冻面团的生产和抑制冰晶的生成。多种类型的NMR数据均可确定面团的玻璃化转变发生在约-30℃,而结晶温度为-9℃。冷冻面团中的水分可以分为三类:固态冰(29.71%);未冻结水(22.20%);深层结合水(33.81%)。     

使用快速扫描DSC检测未干鱼胶的玻璃化转变过程

0引言未经干燥的生物高分子的玻璃化转变过程测试对于传统的DSC技术来说是非常困难的,因为其玻璃化转变过程经常被水分蒸发过程所遮掩。对于玻璃化转变温度在100℃到0℃之间的生物材料来说,这种令人烦恼的现象更为常见。Hyper DSC技术可以根据两种重叠过程所具有的不同的动力学性质对其进行区分,所以在快速扫描DSC（Hyper DSC）的基础上可以实现传统DSC技术所无法进行的分析测试。功率补偿式双炉体DSC仪器具有卓越的性能,例如极短的热平衡时间、高灵敏度与高分辨率等,这些都为Hyper DSC技术的实现提供了足够的支持。     

表达重组蛋白的CHO-GS细胞的无血清培养

采用DOEHLERT和HADAMARD统计方法建立了一个适于重组CHOGS细胞生长和外源蛋白表达的无谷氨酰胺无血清培养基SFMB。对多种硫酸多聚糖进行了考察,选取低分子量硫酸葡聚糖,添加浓度为25mg/L,可以避免细胞结团。用SFMB在方瓶中培养重组CHOGS细胞,细胞生长优于含10%小牛血清的无谷氨酰胺DMEM/F12培养,最大细胞密度提高了40.7%,外源蛋白的表达水平也得到提高。在100ml转瓶中分批培养,最大细胞密度和蛋白表达分别达到1.5×106cells/ml和0.48mg/L。     

A Study on the Preparation and Anti-Tumor Efficacy of Bovine Serum Albumin Nanospheres Containing 5-Fluorouracil

ABSTRACT

The therapeutic profile of many anti-cancer drugs has been improved by their modified distribution through a colloidal carrier system. Hence, bovine serum albumin nanospheres containing 5-fluorouracil were prepared by pH-coacervation methods. To select the most suitable cryoprotector for the formulated nanosphere system, a study on the effect of cryoprotectors in the prevention of particle agglomeration was done. Using glucose and mannitol at various concentrations during freeze drying, glucose at a concentration of 5% was observed to be relatively more effective in the prevention of particle agglomeration than the other cryoprotectors. The carrier capacity was determined through the drug-to-albumin ratio. The particle size of all the drug-loaded batches was analyzed before and after freeze drying. The batch of nanospheres with uniform size distribution, and highest drug loading, was used for other subsequent studies. The effect of surfactant in drug loading was estimated through various concentrations of sodium lauryl sulfate, and it was observed that the surfactant has no influence on drug loading at the selected concentrations. The batch of nanospheres with highest drug loading was evaluated for its in-vitro release, and the drug release was found to be in a bi-phasic pattern. To evaluate the efficacy of 5-fluorouracil-loaded nanospheres against cancer cells, an in vitro cytotoxicity study was carried out using HEp-2 cell lines. The nanosphere-bound drug was observed to produce a better cytotoxic effect than the free drug. The anti-tumor efficacy of drug-loaded nanosphere was investigated in DLA tumor-induced mice models, and the percentage tumor inhibition was relatively higher in animals treated with nanosphere-bound drug than with free drug.     

Study of Biodistribution of Methotrexate-Loaded Bovine Serum Albumin Nanospheres in Mice

Nanospheres made from natural hydrophilic polymers have been proved efficient in terms of better drug-loading capacity, biocompatibility, and possibility less opsonization by reticuloendothelial system (RES) through an aqueous stearic barrier. Hence, nanospheres containing methotrexate were prepared from bovine serum albumin (BSA) by a novel pH coacervation method. A drug-to-polymer ratio study was carried out to determine the carrier capacity. The batch with the highest drug loading was subjected to in vitro analysis. It was found to provide a slow release after an initial burst release. Biodistribution of nanosphere-bound drug was compared with that of free drug in mice. It was observed that the percentage increase in drug distribution to the lungs, liver, and spleen was markedly high from the nanosphere when compared to free drug.     

弹性介质中各向异性球壳的自由振动

用三种壳体理论分析了Ｐａｓｔｅｒｎａｋ型弹性介质中球面各向同性球壳的非轴对称自由振动，得到了两类不同形式的自由振动频率方程，弹性介质只对第二类振动有影响。对三种壳体理论作了数值计算，并和三维弹性理论作了比较，表明六模态中厚壳理论有较高的精度和较广的适用范围。     

Preliminary evaluation of the in vitro release and in vivo absorption in rabbits of the modified-release dosage forms

Objective: The suitability of the rabbit as an animal model for the primary screening and selection of the pilot scale batches during the early stages of the formulation development was studied.

Materials and methods: Three modified-release formulations of aminophylline consisted of Carbopol® 971P/HPMC K4M (F-I), and HPMC K100M (F-II) or HPMC K4M (F-III) were used. Commercial products were Aminofilin retard 350?mg tablets, Srbolek, Serbia (R-I) and Phyllocontin^® 350, tablets Purdue Frederic, Canada (R-II).

Results: Calculated release rate constants and the ?2 values between R-I/F-I (84.1) and R-II/F-III (83.4) indicated similar in vitro release while the coefficient n showed presence of different mechanisms of release from Anomalous transport, Fickian diffusion to Case-II transport. Higher T_max, was found in the rabbits, dosed with F-II (12.00?h), F-III (10.50?h), and R-II (15.00?h) formulation. The highest C_max (9.22?mg/L) was obtained with F-II, similar lower values was seen for F-I and F-III, while commercial products showed the lowest values R-I (5.58?mg/L) and R-II (4.18?mg/L). Higher AUC values were detected for all three formulations (from 115.90 to 204.06 mgh/L) in relation to commercial products (105.33 and 113.25 mgh/L).

Discussion and conclusion: The results demonstrated a good correlation of Level A (r² = 0.97) for the two formulations (F-I, F-III) and commercial product (R-I) indicates that there is a reasonable assumption that the rabbit might be use as a model for the preliminary comparison of scale up formulations in the early stages of the product development.     

Freeze drying: exploring potential in development of orodispersible tablets of sumatriptan succinate

The present investigation is aimed at development and characterization of sumatriptan succinate orodispersible tablets (ODTs) prepared by freeze drying technology. The tablet excipients were screened and the composition was optimized based on parameters which involved general appearance, tablet size and shape, uniformity of weight, mechanical properties, surface pH, moisture analysis, drug content, wetting time, in vitro and in vivo disintegration time. Furthermore, fourier transform infrared spectroscopy, differential scanning calorimetry, scanning electron micrograph of cross-section of the tablet and in vitro dissolution studies were performed. Studies revealed that formulation containing gelatin–mannitol (3.75% w/v and 3.5% w/v, respectively) with camphor as a volatile pore forming agent exhibited superior properties with disintegration time of less than 10?s. Furthermore, in vitro release studies revealed 90% release of drug from developed dosage form within 10?min, thus suggesting rapid drug dissolution followed by faster onset of action, which forms a strong rationale for development of ODTs of sumatriptan succinate. The developed technology is simple, which involves few steps and can be easily scaled up. Thus, it holds enormous potential for commercial exploitation.     

NR光度法测定Fenton试剂所生成的羟基自由基

要提高Fenton试剂在废水处理中的效率,关键就是要提高羟自由基的生成率和利用率。本文提出了检测Fenton试剂反应产生羟自由基的新方法,羟自由基氧化中性红使其褪色,用分光光度法测定其△A值的变化,可间接测定羟自由基的产生量。并考查了FeSO4投加量、H2O2投加量、酸度、反应时间等影响羟自由基生成量的主要因素,为Fenton试剂在废水处理中的应用提供了参数依据。另外,该法稳定性好,操作简单,测定快速。     

Improved initial burst of estradiol organogel as long-term in situ drug delivery implant: formulation,in vitro and in vivo characterization

Objective: The present investigation was aimed at optimizing of estradiol (E2) loaded l-amino acid derivatives organogel formulations resulting in improved the high initial release problems and sustained release of E2.

Methods: The visco-elastic properties of blank organogels were measured by rheometer. The E2 organogel formulations were optimized using a central composite design. Also, the effect of gelator structure and composition of the gel formulations on release behavior (in vitro and in vivo) had been studied.

Results: The change of the gelator structure could affect significantly the stiffness of the implants. The release behavior of gel without N-Methyl-2-pyrrolidinone (NMP) was controlled by gel corrosion only. While the drug release of the gel with NMP was controlled by both corrosion and diffusion. The high initial release problems of the organogels were improved by optimizing the formulations. The system consisting by N-Lauroyl l-lysine methyl ester (LLM) derivative in the oil indicated the lowest initial drug release, showed a much lower blood drug level and maintained a steady state for nearly 1 month.

Conclusion: Organogels based on l-lysine methyl ester derivative were ideal carriers for long-term parenteral administration of E2.     

载紫杉醇聚乳酸-羟基乙酸纳米粒的体外释药研究

以生物可降解材料聚乳酸-羟基乙酸(PLGA)为载体制备了载紫杉醇纳米粒,重点考察了纳米粒的体外释放特性.采用乳化-溶剂挥发法制备了载紫杉醇PLGA纳米粒,其平均粒径为200nm,载药量为21%,包封率为89.44%;体外释药符合Higuchi方程:Q=3.8796t1/2+30.4649(r=0.9397),同时载紫杉醇纳米粒具有一定的缓释作用.     

卤虫体外转录模型及其转录活性检测

通过改进的细胞核提取方法,获取了纯度较高的细胞核并建立了卤虫体外转录系统模型。将待基因与含转录起始位点的报告基因的编码序列相连,制备成体外转录模块。由于体外转录所产生的RNA量极少,需要一种灵敏的方法检测生成的RNA。应用了RT－PCR技术鉴定体外转录产物的方法能有效解决这一问题。转录后,用无RNase的DNaseI将DNA模板完全降解;生成的RNA经逆转录反应合成cDNA,再以cDNA为模板,用相应的引物进行PCR扩增,琼脂糖凝胶电泳检测结果。该法灵敏度高,操作简单安全,无需同位素。     

Studies on the in vitro and in vivo degradation behavior of amino acid derivative-based organogels

The in vitro degradation behavior of organogel with different gelators based on amino acid was investigated in detail. Two methods were applied in this research: weighting method and high-performance liquid chromatography with evaporative light scattering detection (HPLC-ELSD) method, which was established for the first time. Their degradation behaviors in vivo were investigated by varying the kind and concentration of gelators via subcutaneous implantation. The results showed that the stronger the gelation ability or the higher the gelator concentration, the slower the degradation rate of organogel. Moreover, the organogel prepared by oils with longer alkyl length degraded slower than that of the shorter ones, which also decreased in thermal stability and mechanical strength. The investigation on degradation process showed that the degradation rate was mainly controlled by the collapse of network structure formed by gelators. In conclusion, organogel had a tunable degradation rate through altering the gelator type, oil type and the gelator concentration. It remains a promising candidate for subcutaneous in-situ implant as drug delivery vehicle.