SE-HPLC测定太子神悦胶囊中多糖相对分子质量分布及含量

 目的建立高效液相色谱法测定多糖相对分子质量和含量的方法;分析太子神悦胶囊中多糖的相对分子质量分布和含量测定。方法采用SephadexG-100凝胶柱纯化分离不同相对分子质量的多糖组分,用TSK-GELG3000SW,7.8mm×300mm色谱柱,2410示差折光检测仪,测定其相对分子质量分布和含量。结果太子神悦胶囊中相对分子质量17.0×10³-27.0×10³的多糖(JNTP2)的含量为(0.805±0.01)%;相对分子质量分布为Mr:24×10³;Mn:17×10³;Mp:27×10³;Mr/Mn为1.4结论建立了简便、快捷、精密度高的凝胶色谱方法;较为准确的测定了太子神悦胶囊中多糖的含量和相对分子质量分布,为制定太子神悦胶囊多糖的质量标准提供依据。     

香榧假种皮中紫杉醇的检定

目的:检定香榧假种皮中紫杉醇.方法:以乙醇、乙酸丁酯、氯仿为溶剂,采用溶剂直接浸取和索氏提取两种方法萃取香榧假种皮,提取物经萃取纯化后,通过HPLC测定其中的紫杉醇含量,通过流动注射质谱检测其中是否含有紫杉醇类似物.结果:香榧假种皮中紫杉醇含量少于0.003%,提取物中紫杉醇类物质的含量非常少.结论:香榧假种皮作为紫杉醇药源的开发价值不大.     

灯盏花素在家犬与家兔体内的药代动力学研究

目的:研究灯盏花素在家犬与家兔体内的药代动力学.方法:采用液-液萃取法制备血样供试品,HPLC法测定.结果:灯盏花素在家犬体内的过程符合双室模型,主要药动学参数为:A=56.93±23.14,B=1.61±1.11,α=0.2328±0.1321min-,β=0.0255±0.0187min-,T1/2α=2.98±1.42min,T1/2β=27.14±14.35min,K21=0.0312±0.0112min-,K10=0.1904±0.1319min-,K12=0.0367±0.0306min-1,CL=39.41±20.44ml·min-,AUC=3074±1055mg·min·L-;灯盏花素在家兔体内的过程符合双室模型,主要药动学参数为:A=2.64±1.12,B=0.28±0.12,α=0.1439±0.0681min-,β=0.0162±0.0456min-,t1/2α=4.82±1.65min,t1/2β=42.66±18.77min,K21=0.0285±0.0147min-,K10=0.0820±0.00378min-,K12=0.0496±0.0241min-,CL=337.05±156.48ml·min-1,AUC=356±114mg·min·L-1.结论:灯盏花素在家犬与家兔体内半衰期很短,其作用时间短,消除速度快.     

胰岛素脂质体的制备及在电致孔下的经皮渗透

采用反相蒸发法制备了平均粒径122.7nm的胰岛素脂质体,并考察了电致孔经皮转运情况.结果表明,在电致孔条件下,胰岛素脂质体2h累积渗透量是载药脂质体被动扩散的1倍;是原药及其与空白脂质体混合物的2～3倍.     

On revenue maximization for selling multiple independently distributed items

Consider the revenue-maximizing problem in which a single seller wants to sell k different items to a single buyer, who has independently distributed values for the items with additive valuation. The case was completely resolved by Myerson’s classical work in 1981, whereas for larger k the problem has been the subject of much research efforts ever since. Recently, Hart and Nisan analyzed two simple mechanisms: selling the items separately, or selling them as a single bundle. They showed that selling separately guarantees at least a fraction of the optimal revenue; and for identically distributed items, bundling yields at least a fraction of the optimal revenue. In this paper, we prove that selling separately guarantees at least fraction of the optimal revenue, whereas for identically distributed items, bundling yields at least a constant fraction of the optimal revenue. These bounds are tight (up to a constant factor), settling the open questions raised by Hart and Nisan. The results are valid for arbitrary probability distributions without restrictions. Our results also have implications on other interesting issues, such as monotonicity and randomization of selling mechanisms.     

Necrosis,sarcolemmal damage and apoptotic events in myofibers rejected by CD8+ lymphocytes: Observations in nonhuman primates

To detect the mechanisms of death in allogeneic myofibers rejected by the immune system, myoblasts were allotransplanted in muscles of macaques immunosuppressed with tacrolimus. Immunosuppression was stopped 1 month later to induce a massive rejection of allogeneic myofibers. Grafted sites were biopsied at 2-week intervals and analyzed by histology. The loss of allogeneic myofibers was rapid and concomitant with an intense infiltration of CD8+ lymphocytes. Several necrotic myofibers were observed in the lymphocyte accumulations by intracellular complement immunodetection. Dystrophin and spectrin immunodetection showed sarcolemmal damage in myofibers surrounded and invaded by CD8+ lymphocytes. Active caspase-3 was immunodetected in some myofibers surrounded by CD8+ lymphocytes. This is the first evidence that the collapse of myofibers attacked by T lymphocytes occurs by necrosis possibly due to damage of the sarcolemma. Caspase 3 is activated at least in some myofibers, but there was no evidence of a complete classical process of apoptosis.     

Quantification of coronary arterial stenoses in CTA using fuzzy distance transform

Quantification of coronary arterial stenoses is useful for the diagnosis of several coronary heart diseases. Being noninvasive, economical and informative, computed tomographic angiography (CTA) has become a common modality for monitoring disease status and treatment effects. Here, we present a new method for detecting and quantifying coronary arterial stenosis in CTA using fuzzy distance transform (FDT) approach and a new coherence analysis of observed data for computing expected local diameter. FDT allows computing local depth at each image point in the presence of partial voluming and thus, eliminates the need for binarization, commonly, associated with inclusion of additional errors. In the current method, coronary arterial stenoses are detected and their severities are quantified by analyzing FDT values along the medial axis of an arterial tree obtained by its skeletonization. A new skeletal pruning algorithm has been developed toward improving the quality of medial axes and thereby, enhancing the accuracy of stenosis detection and quantification. Further, we have developed a new method to estimate “expected diameter” along a given arterial branch using a new coherence analysis of observed diameter values along the branch. The overall method is completed in the following steps - (1) fuzzy segmentation of coronary artery in CTA, (2) FDT computation of coronary arteries, (3) medial axis computation, (4) estimation of observed and expected diameters along arteries and (5) detection of stenoses and quantification of arterial blockage. The performance of this method has been quantitatively evaluated on a realistic coronary artery phantom dataset with randomly simulated stenoses and the results have been compared with a binary distance transform based and a conventional binary algorithm. The method has also been applied on a clinical CTA dataset from thirteen heart patients and the results have been compared with an expert's quantitative assessment of stenoses. Results of the phantom experiment indicate that the new method (error: 0.53%) is significantly more accurate as compared to both binary distance transform based (error 2.11%) and conventional binary (error 3.71%) methods. Also, the results of the clinical study indicate that the new FDT-based method (kappa coefficient = 87.9%) is highly in agreement with the expert's assessments and, in this respect, outperforms the other two methods (kappa coefficients = 75.2% and 69.5%).     

Alternative payment models and physician treatment decisions: Evidence from lower back pain

The capitated payment model has been used to address the high cost of health care. Under capitation, physicians are compensated with a fixed amount per patient, regardless of the services generated. We provide new evidence on how the capitation payment model changes physicians behaviors by studying the treatment of lower back pain, as this type of treatment provides substantial scope for physicians discretion. We use data from 2003 to 2006 from a large database of employer-sponsored health insurance claims and leverage capitation variation within the plan and physician to mitigate selection concerns. The results show that the treatment intensity—primarily derived from therapy and diagnostic testing —of patients under a capitation system is 7–12% lower than that of similar patients in a non-capitated plan. Furthermore, we find no evidence of increased relapse rates for patients in a capitated plan.     

持续泵入生长抑素时防止发生低血糖的方法

目的探讨安全使用生长抑素不发生低血糖反应的方法。方法密切监测血糖,在患者输完营养液后血糖低于6.1 mmol/L者用5%葡萄糖维持输入。结果用5%葡萄糖维持输入的患者未发生低血糖。结论在患者输完营养液后应用5%葡萄糖可防止低血糖的发生。