Lipid contribution to the affinity of antigen association with specific antibodies conjugated to liposomes

Immunoliposomes, directed to clinically relevant cell-surface molecules with antibodies, antibody fragments or peptides, are used for site-specific diagnostic evaluation or delivery of therapeutic agents. We have developed intrinsically echogenic liposomes (ELIP) covalently linked to fibrin(ogen)-specific antibodies and Fab fragments for ultrasonic imaging of atherosclerotic plaques. In order to determine the effect of liposomal conjugation on the molecular dynamics of fibrinogen binding, we studied the thermodynamic characteristics of unconjugated and ELIP-conjugated antibody molecules. Utilizing radioimmunoassay and enzyme-linked immunosorbent assay protocols, binding affinities were derived from data obtained at three temperatures. The thermodynamic functions DeltaH(o) , DeltaG(o) and DeltaS(o) were determined from van't Hoff plots and equations of state. The resultant functions indicated that both specific and nonspecific associations of antibody molecules with fibrinogen occurred through a variety of molecular interactions, including hydrophophic, ionic and hydrogen bonding mechanisms. ELIP conjugation of antibodies and Fab fragments introduced a characteristic change in both DeltaH(o) and DeltaS(o) of association, which corresponded to a variable contribution to binding by phospholipid gel-liquid crystal phase transitions. These observations suggest that a reciprocal energy transduction, affecting the strength of antibody-antigen binding, may be a singular characteristic of immunoliposomes, having utility for optimization and further development of the technology.     

EFFECT OF ASSESSORS EXPERTISE LEVEL ON EFFICIENCY OF WARM-UP FOR TRIANGLE TESTS

The effect of warm-up on performance for repeated triangle tests is studied according to assessors' expertise level for both triangle test strategy and the pair of products to compare. Three experiments performed with orange flavored soft drinks show that the effect of warm-up depends on the assessors' expertise: (1) naive assessors do not increase their performance with warm-up; (2) assessors with a moderate practice of both triangle tests and the pair of products improve their performance with warm-up; (3) assessors with a moderate practice of triangle tests, but not familiar with the pair of products, improve their performance with warm-up too; and (4) assessors highly experienced for both triangle tests and products do not improve their performance with warm-up. These results support the idea that the positive effect of warm-up is due to an attentional process: Warm-up seems to help assessors focusing their attention on the dimension on which the two products are actually different and ignoring the other dimensions. Thus, results show that assessors are able to learn the difference between the two products and to learn to focus their attention on this difference at any time. They also suggest that prior knowledge of the triangle test scheme is required to benefit from warm-up.     

LMO3过表达对胶质细胞增殖的作用

构建重组质粒pcDNA4/HisA-LMO3,转染C8-D1A胶质细胞,对照组为pcDNA4/HisA空载体质粒转染组和未转染组,MTT观察各组细胞的体外生长情况,流式细胞术(FCM)测定各组细胞的细胞周期和凋亡细胞百分比,Western-blot检测LMO3转染后凋亡相关蛋白的表达变化,从而观察LMO3基因对C8-D1A胶质细胞体外生长的影响.RT-PCR、Western印迹显示pcDNA4/HisA-LMO3转染组LMO3mRNA及LMO3蛋白表达水平明显高于对照组;与对照组细胞相比,转染组细胞的增殖能力明显高于空载体对照组及C8细胞(P0.01),S期细胞增加,G0/G1期细胞减少,C8细胞转染LMO3后可以促进C8细胞从G0/G1期进入S期,从而促进细胞的增殖.     

纤维素在不同介质中的吸附碱的研究

文中研究了纤维素在不同介质(水、乙醇、吡啶及N,N-二甲基乙酰胺)中吸附碱测定情况并通过对比总结出了纤维素对氢氧化钠随用碱量及介质变化规律:纤维素的吸附碱量随着介质及用碱量不同而有所变化,用水作碱化介质比用有机溶剂/水作碱化介质时的吸附碱量少;在用有机溶剂/水作碱化介质时,纤维素对碱吸附表现出大致相同的变化趋势。     

Intracellular delivery of VIP-grafted sterically stabilized phospholipid mixed nanomicelles in human breast cancer cells

The purpose of this study was to determine whether biocompatible and biodegradable vasoactive intestinal peptide-grafted sterically stabilized phospholipid mixed nanomicelles (VIP-SSMM; size, approximately 15 nm), a novel nanosized actively targeted drug delivery platform for breast cancer, accumulate in human MCF-7 breast cancer cells. Using hydrophobic CdSe/ZnS quantum dots (QD), we found that QD-loaded VIP-SSMM accumulated significantly faster and in greater quantity in MCF-7 cells than did QD-loaded SSMM alone (p<0.05). This process was mediated, in part, by VIP receptors because excess human VIP, but not PACAP(6-38) or galanin, significantly attenuated this response (p<0.05). Taken together, these data indicate that VIP-SSMM are actively targeted to human breast cancer cells through VIP receptors. We suggest that VIP-SSMM could be used as an actively targeted nanosized drug delivery platform for breast cancer cells over-expressing VIP receptors.     

γ射线辐照灭菌剂量的模糊优化

γ射线辐照灭菌处理的关键性技术是辐照剂量的优化和确定。通过对照射后的SPF试验动物饲料的理化、微生物和感官指标的分析,提出γ辐照灭菌处理的模糊综合质量评价方法,进而实现对辐照剂量的模糊优化。     

甲基纤维素辐射降解及工艺研究

介绍了^60Co γ－射线对甲基纤维素的辐射降解作用,初步研究了辐射剂量、剂量率对甲基纤维素粘的影响。评价了甲基纤维素辐照后的贮存稳定性,并对辐射降解工艺进行了探讨。     

GROWTH RESPONSE OF SALMONELLA SPP. TO CYCLOHEXIMIDE AMENDMENT IN MEDIA

The present study was designed to evaluate cycloheximide as a potential media amendment to prevent fungal overgrowth on selective media for salmonellae enumeration. The objectives were to determine the effect of cycloheximide on Salmonella spp growth rates and to determine the effect of cycloheximide addition on Salmonella enumeration in selective media. The bacteria tested included two strains of Salmonella typhimurium (NO/NA and LT2) and one strain of Salmonella arizonae. All strains were grown in tryptic soy broth containing cycloheximide to determine the effect of cycloheximide on bacterial specific growth rates. The growth rate of all strains grown in tryptic soy broth were not significantly influenced by addition of cycloheximide at concentrations up to 1,000 mg/L. Growth rates of S. typhimurium NO/NA in minimal media were significantly decreased by addition of cycloheximide aerobically (300 mg/L) and anaerobically (600 mg/L). However, S. typhimurium NO/NA populations on brilliant green agar, MacConkey agar, and from selenite cysteine broth and tetrathionate broth were not affected by cycloheximide additions at concentrations up to 1,000 mg/L. Cycloheximide has potential as a fungistat additive for salmonellae selective media.     

Molecular phylogenetics of Stenodermatini bat genera: congruence of data from nuclear and mitochondrial DNA

Within the tribe Stenodermatini the systematics of the complex of species allied with the genus Artibeus has generated several alternative phylogenetic hypotheses. The most recent treatment recognized four genera (Artibeus, Dermanura, Enchisthenes, and Koopmania) and suggested that the most recent common ancestor of these four genera would include the common ancestor of all other currently recognized Stenodermatini genera except Sturnira. To test this hypothesis, we examined an EcoRI-defined nuclear satellite DNA repeat and 402 bp of DNA sequence variation from the mitochondrial cytochrome b gene. Phylogenetic conclusions based on Southern blot analyses, in situ hybridization, and mitochondrial DNA sequence data indicate that Enchisthenes is not closely related to Dermanura, Artibeus, or Koopmania and that Dermanura, Artibeus, and Koopmania shared a common ancestor after diverging from the remainder of the Stenodermatini. If our conclusions are correct, then justification for recognizing Dermanura and Koopmania as generically distinct from Artibeus must be based on the magnitude of difference that distinguishes each rather than on the conclusion that to place them as congeneric with Artibeus creates a paraphyletic taxon.