p21WAF1／CIPI基因导入对p53突变人肺癌细胞系生长特性的影响

目的 探讨含突变ｐ５３基因癌细胞系ｐ２１基因的抗肿瘤作用。方法 构建人ｐ２１表达重组子,导入ｐ５３基因突变的人肺癌ＰＧ细胞每当增产同表达ｐ２１的细胞系;然后观察其形态太生长特性的改变;ＣＤＫ４,ＰＣＮＡ水平;对基因毒性物的反应性。结果 在含ｐ５３基因突变的ＰＧ细胞内导入的性ｐ２１基因,其高表达ｐ２１约是ＰＧ细胞的６倍,转谬为薄等异型性降低;生长速度下降（５０％）,叠落生长不明显;在０．５％血甭条件     

High density of immobilized galactose ligand enhances hepatocyte attachment and function

Galactosylated surface is an attractive substrate for hepatocyte culture because of the specific interaction between the galactose ligand and the asialoglycoprotein receptor on hepatocytes. In this study, we described a scheme to achieve high density of immobilized galactose ligands on polyethylene terephthalate (PET) surface by first surface-grafting polyacrylic acid on plasma-pretreated PET film under UV irradiation, followed by conjugation of a galactose derivative (1-O-(6'-aminohexyl)-D-galactopyranoside) to the grafted polyacrylic acid chains. A high galactose density of 513 nmol/cm(2) on the PET surface was used in this study to investigate the behavior of cultured hepatocyte. This engineered substrate showed high affinity to fluorescein isothiocyanate-lectin binding. Primary rat hepatocytes, when seeded at a density of 2 x 10(5) cells/cm(2), attached to the galactosylated PET substrate at a similar efficiency compared with collagen-coated substrate. The hepatocytes spontaneously formed aggregates 1 day after cell seeding and showed better maintenance of albumin secretion and urea synthesis functions than those cultured on collagen-coated surface.     

Adhesion contact dynamics of HepG2 cells on galactose-immobilized substrates

The specific recognition between asialoglycoprotein receptor and galactose ligand at cell-substrate interfaces has been shown to mediate hepatocyte adhesion and maintain liver specific functions of hepatocytes. Conventionally, the success of hepatocyte attachment on engineered tissue scaffold is inferred from the degree of two-dimensional cell spreading that is measured by transmitted light microscopy. However, the actual contact mechanics and adhesion strength of hepatocytes during two-dimensional cell spreading has not been elucidated due to lack of biophysical probe. In this study, a novel biophysical technique known as confocal reflectance interference contrast microscopy (C-RICM) in conjunction with phase contrast microscopy is utilized to probe the adhesion dynamics, contact mechanics and two-dimensional spreading kinetics of HepG2 cells on galactose immobilized and collagen gel coated substrates. C-RICM demonstrates that HepG2 cells form strong adhesion contacts with both galactose-immobilized surfaces and collagen gel coated substrates. Moreover, HepG2 cells maintain their compact shapes in the presence of asialoglycoprotein receptor-mediated recognition while they become exceedingly spread under integrin-mediated adhesion on collagen gel coated substrate. The initial rate of adhesion contact formation and the steady-state adhesion energy of HepG2 cell population are highest on substrate conjugated with galactose ligand via a longer spacer. The adhesion dynamics and final adhesion energy of HepG2 cells depends both on the type of ligand-receptor interaction and the length of spacer between the ligand and substrate. Most importantly, new biophysical insights into the initial hepatocyte attachment that are critical for hepatocyte culture are provided through the decomposition of two-dimensional spreading and adhesion contact formation on bio-functional substrates.     

Analysis of fMRI data by blind separation of data in a tiny spatial domain into independent temporal component

Independent Component Analysis (ICA) is a promising tool for the analysis of functional magnetic resonance imaging (fMRI) time series. In these studies, mostly assumed is a spatially independent component map of fMRI data (spatial ICA). In this paper, we assume that the temporal courses of the signal and noises are independent within a Tiny spatial domain (temporal ICA). Then with fast-ICA algorithm, spatially neighboring fMRI data were blindly separated into several temporal courses and were preassumed to be formed by a signal time course and several noise time courses where the signal has the largest correlation coefficient with the reference signal. The final functional imaging was completed for the signals obtained from each voxel. Simulations showed that compared with the spatial ICA method, the new temporal ICA method is more effective than the spatial ICA in detecting weak signal in a fMRI dataset. As background noise, the simulations include simulated Gaussian noise and fMRI data without stimulation. Finally, vivo fMRI tests showed that the excited areas evoked by a visual stimuli are mainly in the region of the primary visual cortex and that evoked by auditory stimuli are mainly in the region of the primary temporal cortex.     

Synthesis and drug release behavior of poly (trimethylene carbonate)-poly (ethylene glycol)-poly (trimethylene carbonate) nanoparticles

ABA-type triblock copolymers poly (trimethylene carbonate)-poly (ethylene glycol)-poly (trimethylene carbonate) were synthesized by ring-opening polymerization of trimethylene carbonate initiated by dihydroxyl poly (ethylene glycol). The critical micelle concentration of amphiphilic triblock copolymers in aqueous solution was determined by fluorescence spectroscopy using 9-chloromethyl anthracene as fluorescence probe. Core-shell-type nanoparticles were prepared by the dialysis technique. Transmission electron microscopy images showed that these nanoparticles were regularly spherical in shape. Micelle size determined by dynamic light scattering is 50-160 nm. Anticancer drug methotrexate (MTX) as model drug was loaded in the polymeric nanoparticles. X-ray powder diffraction spectra showed that model drugs were molecularly dispersed in the core. In vitro release behavior of MTX was investigated.     

A selective role of calcineurin aalpha in synaptic depotentiation in hippocampus

Pharmacological studies have suggested that long-term potentiation (LTP) and long-term depression (LTD) and depotentiation, three forms of synaptic plasticity in the hippocampus, require the activity of the phosphatase calcineurin. At least two different isoforms of calcineurin are found in the central nervous system. To investigate whether all of these forms of synaptic plasticity require the same isoforms of calcineurin, we have examined LTD, depotentiation, and LTP in mice lacking the predominant calcineurin isoform in the central nervous system, Aalpha-/- mice. Depotentiation was abolished completely whereas neither LTD nor LTP were affected. These studies provide genetic evidence that the Aalpha isoform of calcineurin is important for the reversal of LTP in the hippocampus and indicate that depotentiation and LTD operate through somewhat different molecular mechanisms.