神经细胞黏附分子样蛋白对小鼠NK细胞活性的影响

目的　研究神经细胞黏附分子样蛋白对小鼠NK细胞活性的影响。方法　将神经细胞粘附分子样蛋白的编码基因连接在补体C3d基因的下游 ,构建融合基因 ,再将此融合基因克隆入真核细胞表达质粒。用此重组质粒免疫小鼠 ,检测小鼠体内的抗体和NK细胞的活性。结果　小鼠体内产生了神经细胞粘附分子样蛋白的特异性抗体 ,而且小鼠脾细胞的NK活性增强。结论　神经细胞粘附分子样蛋白可能具有抑制NK细胞的活性 ,在被特异性抗体识别和结合后 ,这种抑制作用减弱或消失。     

The Role of Cell Adhesion Molecule 1 (CADM1) in Cutaneous Malignancies

Cell adhesion ability is one of the components to establish cell organization and shows a great contribution to human body construction consisting of various types of cells mixture to orchestrate tissue specific function. The cell adhesion molecule 1 (CADM1) is a molecule of cell adhesion with multiple functions and has been identified as a tumor suppressor gene. CADM1 has multifunctions on the pathogenesis of malignancies, and other normal cells such as immune cells. However, little is known about the function of CADM1 on cutaneous cells and cutaneous malignancies. CADM1 plays an important role in connecting cells with each other, contacting cells to deliver their signal, and acting as a scaffolding molecule for other immune cells to develop their immune responses. A limited number of studies reveal the contribution of CADM1 on the development of cutaneous malignancies. Solid cutaneous malignancies, such as cutaneous squamous cell carcinoma and malignant melanoma, reduce their CADM1 expression to promote the invasion and metastasis of the tumor. On the contrary to these cutaneous solid tumors except for Merkel cell carcinoma, cutaneous lymphomas, such as adult-T cell leukemia/lymphoma, mycosis fungoides, and Sézary syndrome, increase their CADM1 expression for the development of tumor environment. Based on the role of CADM1 in the etiology of tumor development, the theory of CADM1 contribution will desirably be applied to skin tumors according to other organ malignancies, however, the characteristics of skin as a multicomponent peripheral organ should be kept in mind to conclude their prognoses.     

In vitro degradation and protein release of semi‐IPN hydrogels consisted of poly(acrylic acid‐acrylamide‐methacrylate) and amylose

The enzymatic degradation mechanism of semi‐interpenetrating network (semi‐IPN) hydrogel of poly (acrylic acid‐acrylamide‐methacrylate) crosslinked by azocompound and amylose in vitro was investigated in the presence of Fungamyl 800L (α‐amylase) and rat cecum content (cecum bacteria). The degradation mechanism involves degradable competition, i.e., reduction of azo crosslinkage is dominant in the earlier period of degradation. Subsequently, the degradation of gels is continued by combination of reduction of azo crosslinkage and hydrolysis of amylose. The cumulative release ratios of Bovine serum albumin (BSA, as a model drug) loaded semi‐IPN gels are 25% in pH 2.2 buffer solutions and 74% in pH 7.4 buffer solutions within 48 h. Moreover, the release behavior of BSA from the semi‐IPN gels indicates that it follows Fickian diffusion mechanism in pH 2.2 media and non‐Fickian diffusion and polymer chains relaxation mechanism in pH 7.4 media. The results indicate that the release of BSA from the semi‐IPN gels was controlled via a combined mechanism of pH dependent swelling and specificity to enzymatic degradation. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Photosensitive poly(urethane acylsemicarbazide)s with azobenzene chromophores in the main chain

Poly(urethane acylsemicarbazide)s were synthesized with a two‐step process: (1) the in situ generation of diisocyanate through the thermal decomposition of an azobenzene‐containing precursor diazide and a reaction with ester/ether polyols to form an isocyanate‐terminated prepolymer and (2) chain extension in N,N‐dimethylacetamide with aliphatic or aromatic dihydrazides. Films cast from N,N‐dimethylacetamide solutions were characterized with attenuated total reflection/Fourier transform infrared spectroscopy, and the thermal properties were studied with thermogravimetric analysis and differential scanning calorimetry. The effects of the hard‐segment content and chain extenders on the static and dynamic mechanical properties were investigated. The photoresponsive behavior of the polymers and the effects of variations in the chromophore concentration and chemical composition on the kinetics of photoisomerization were investigated with ultraviolet–visible spectroscopy, which revealed that the rates were independent of the chromophore concentration. The photomechanical behavior, assessed with creep‐recovery measurements, proved that the systems underwent photochemical isomerization upon irradiation with ultraviolet light. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 444–454, 2004     

Swelling of crosslinked poly(methylmethacrylate‐acrylic acid) copolymers in serum and saline solutions

In recent articles, our research group explored the use of crosslinked Poly(methylmethacrylate‐acrylic acid) and composites based on this copolymer for bone implant applications such as suture anchors. The swelling response of this system was studied first in vitro, using a 0.85 g/100‐mL saline solution (chosen because it simulates well the in vivo environment), and later in vivo by using samples implanted for various time periods in the lateral femoral condyles of New Zealand white rabbits. It was found that the swelling response of the crosslinked copolymer in vivo was much greater than that in the saline solution. The present investigation was conducted to determine the mechanism of excessive swelling in the in vivo tests. The approach used was to establish the changes occurring in the chemical structure of the copolymer due to immersion in serum. A number of hypotheses that can potentially explain the observed excessive swelling in serum were investigated and are discussed in this article. The results of this study indicate that the mechanism of excessive swelling in serum was the neutralization of  COOH groups in the copolymer to produce salts of acrylic acid, which are known to result in greater swell due to their higher degree of dissociation compared to free acid. It was also found that, for compositions containing the acrylic salts (produced by preswelling in high pH solutions and drying), the swelling behavior in serum was similar to that in saline solution, and more importantly, equilibrium swelling was reached in a relatively shorter time period, which has several practical advantages for bioimplant applications. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1653–1664, 2001     

The preparation and characterization of high‐performance and thermally stable electroluminescent poly(p‐phenylene‐vinylene‐b‐oligoethylene oxide)

Two luminescent block copolymers (PPVPEO₂₀₀ and PPVPEO₆₀₀), composed of poly(p‐phenylene‐vinylene) (PPV) segments with three phenylene vinylene units and poly(ethylene oxide) (PEO) segments with molecular weight of 200 and 600, respectively, have been successfully synthesized. The structures of the copolymers were verified using FTIR, ¹H‐NMR, and elemental analysis. Single‐layer polymer light‐emitting electrochemical cells (LEC) devices fabricated on the bases of thin films of PPVPEO₆₀₀ and on the bases of thin films of blends of PPVPEO₂₀₀ with additional PEO both demonstrated good electroluminescent (EL) performance with the onset voltage of 2.6 V and EL efficiency of 0.64 cd/A and 0.68 cd/A at 3.2 V, respectively. Thermal analysis shows that the decomposition temperature of PPVPEO₆₀₀ is about 305°C, which is higher than that of PPVPEO₂₀₀ and PEO. AFM studies of PPVPEO₆₀₀ thin films exhibits that the block copolymer self‐assembles to form nanoscale network structures with pseudo‐cross‐linking points, thus accounting for its high thermal stability and good EL performance. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1118–1125, 2007     

Synthesis and self‐assembling behaviors of biotinylated pluronic/poly(lactic acid) biocompatible block copolymers in aqueous solutions

Four kinds of Biotinylated Pluronic/PLA block copolymers were synthesized by two‐step reactions. Pluronic were firstly modified by biotin to obtain B‐Pluronic‐OH. Biotin‐Pluronic‐PLA block copolymers were then produced by ring‐opening polymerization of the monomer L ‐lactide using Biotin‐Pluronic‐OH as the initiator and stannous octoate (Sn(Oct)₂) as the catalyst. The self‐assembling behaviors of Biotin‐Pluronic‐PLA block copolymers in aqueous solutions were examined by fluorescence measurement, dynamic light scattering (DLS), and transmission electron microscopic (TEM) techniques. The size of Biotin‐F127‐PLA‐61, Biotin‐F87‐PLA, and Biotin‐P85‐PLA nanoparticles were determined to be 198, 229, and 257 nm, respectively, and their morphologies were found to be spherical micelles. Biotin‐F127‐PLA‐87 produces both spherical micelles and large compound micelles with the size of 127 and 906 nm. The cytotoxicity studies using human ovarian cancer cells OVCAR‐3 indicate that Biotin‐Pluronic‐PLA block copolymers have good biocompatibility. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Activity‐Fed Translation (AFT) Assay: A New High‐Throughput Screening Strategy for Enzymes in Droplets

There is an increasing demand for the development of sensitive enzymatic assays compatible with droplet‐based microfluidics. Here we describe an original strategy, activity‐fed translation (AFT), based on the coupling of enzymatic activity to in vitro translation of a fluorescent protein. We show that methionine release upon the hydrolysis of phenylacetylmethionine by penicillin acylase enabled in vitro expression of green fluorescent protein. An autocatalytic setup where both proteins are expressed makes the assay highly sensitive, as fluorescence was detected in droplets containing single PAC genes. Adding a PCR step in the droplets prior to the assay increased the sensitivity further. The strategy is potentially applicable for any activity that can be coupled to the production of an amino acid, and as the microdroplet volume is small the use of costly reagents such as in vitro expression mixtures is not limiting for high‐throughput screening projects.     

α‐cyclodextrin assisted self‐assembly of poly(ethylene glycol)‐block‐poly(N‐isopropylacrylamide) in aqueous media

Poly(ethylene glycol)‐block‐poly(N‐isopropylacrylamide) (PEG‐b‐PNIPAM) block copolymers were synthesized by atom transfer radical polymerization, and the α‐cyclodextrin (α‐CD) induced self‐assembly characteristics of the system were elucidated. Below the lower critical solution temperature (LCST) of PNIPAM, CD threaded onto the PEG segments and induced micellization to form rod‐shaped nanostructures comprising of a PEG/α‐CD condensed phase and a PNIPAM shell. Increasing the temperature of system above the LCST caused the PNIPAM segments to collapse, which resulted in the dethreading of the CD. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Chitosan-Modified Poly(2,6-dimethyl-1,4-phenylene Oxide) for Anion-Exchange Membrane in Fuel Cell Technology

A series of cross-linking chitosan-modified quaternary ammonium poly(2,6-dimethyl-1,4-phenylene oxide)s membranes (CS-QAPPO) were prepared by the Menshutkin reaction. The mechanical property, dimensional stability, and alkaline stability of the CS-QAPPO membrane have been impressively improved by introducing CS into PPO backbone. Even the hydroxide conductivity of CS-QAPPO membranes is higher than that of the pristine QAPPO membrane. The 20% chitosan-modified QAPPO membrane shows the best performance, and the hydroxide conductivity is 32 mS cm^?1 at 90°C. The alkaline stability measurements demonstrated excellent chemical stability of the CS-QAPPO membrane in 2?M NaOH solution at room temperature after 2,000?h.     

Synthesis and characterization of polystyrene/poly(4‐vinylpyridine) triblock copolymers by reversible addition–fragmentation chain transfer polymerization and their self‐assembled aggregates in water

Reversible addition–fragmentation chain transfer polymerization (RAFT) was developed for the controlled preparation of polystyrene (PS)/poly(4‐vinylpyridine) (P4VP) triblock copolymers. First, PS and P4VP homopolymers were prepared using dibenzyl trithiocarbonate as the chain transfer agent (CTA). Then, PS‐b‐P4VP‐b‐PS and P4VP‐b‐PS‐b‐P4VP triblock copolymers were synthesized using as macro‐CTA the obtained homopolymers PS and P4VP, respectively. The synthesized polymers had relatively narrower molecular weight distributions (M_w/M_n < 1.25), and the polymerization was controlled/living. Furthermore, the polymerization rate appeared to be lower when styrene was polymerized using P4VP as the macro‐CTA, compared with polymerizing 4‐vinylpyridine using PS as the macro‐CTA. This was attributed to the different transfer constants of the P4VP and PS macro‐CTAs to the styrene and the 4‐vinylpyridine, respectively. The aggregates of the triblock copolymers with different compositions and chain architectures in water also were investigated, and the results are presented. Reducing the P4VP block length and keeping the PS block constant favored the formation of rod aggregates. Moreover, the chain architecture in which the P4VP block was in the middle of the copolymer chain was rather favorable to the rod assembly because of the entropic penalty associated with the looping of the middle‐block P4VP to form the aggregate corona and tailing of the end‐block PS into the core of the aggregates. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1017–1025, 2003     

Localization of Neurotrophin Specific Trk Receptors in Mechanosensory Systems of Killifish (Nothobranchius guentheri)

Neurotrophins (NTs) and their signal-transducing Trk receptors play a crucial role in the development and maintenance of specific neuronal subpopulations in nervous and sensory systems. NTs are supposed to regulate two sensory systems in fish, the inner ear and the lateral line system (LLS). The latter is one of the major mechanosensory systems in fish. Considering that annual fishes of the genus Nothobranchius, with their short life expectancy, have become a suitable model for aging studies and that the occurrence and distribution of neurotrophin Trk receptors have never been investigated in the inner ear and LLS of killifish (Nothobranchius guentheri), our study aimed to investigate the localization of neurotrophin-specific Trk receptors in mechanosensory systems of N. guentheri. For histological and immunohistochemical analysis, adult specimens of N. guentheri were processed using antibodies against Trk receptors and S100 protein. An intense immunoreaction for TrkA and TrkC was found in the sensory cells of the inner ear as well as in the hair cells of LLS. Moreover, also the neurons localized in the acoustic ganglia displayed a specific immunoreaction for all Trk receptors (TrkA, B, and C) analyzed. Taken together, our results demonstrate, for the first time, that neurotrophins and their specific receptors could play a pivotal role in the biology of the sensory cells of the inner ear and LLS of N. guentheri and might also be involved in the hair cells regeneration process in normal and aged conditions.