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1.
The metastatic status of oral cancer is highly associated with the overall survival rate of patients. Previous studies have revealed that the endogenous tryptophan metabolite 5‐methoxytryptophan (5‐MTP) can downregulate cyclooxygenase‐2 expression; suppress tumor proliferation, migration, and invasion; and reduce the tumor size. To improve the understanding of the molecular mechanisms involved in the regulation of 5‐MTP in the tumorigenesis of oral cancer, we conducted a comparative wound healing and transwell invasion assays. Our results revealed that 5‐MTP reduce oral cancer cell migration and invasion ability. In addition, the results of an in vivo assay demonstrated that the growth of primary tumors was significantly inhibited by 5‐MTP in OC3 oral cancer cells and in invasive OC3‐I5 oral cancer cells. Moreover, enlarged spleens were observed in OC3‐I5‐implanted severe combined immunodeficiency mice although 5‐MTP can inhibit spleen enlargement. Through comparative proteomics, we identified 32 differentially regulated protein spots by using 2D‐DIGE/MALDI‐TOF MS analyses. Some of the differentially regulated proteins such as amadillo‐repeat‐containing X‐linked protein 1, phosphoglycerate kinase 1, tropomyosin alpha‐1, and tropomyosin alpha‐4 may be associated with the 5‐MTP‐dependent inhibition of oral cancer growth and metastasis. We conclude that 5‐MTP plays a crucial role in inhibiting in vitro and in vivo cancer invasion and metastasis.  相似文献   

2.
Glutathione reductase (GR), a cytosolic protein, plays a vital role in maintaining a correct redox status in cells. However, comprehensive investigations of GR‐modulated cellular responses, including protein level alteration and redox regulation, have yet to be performed. In this study, we cultured a human lung adenocarcinoma line transfected with empty pLKO.1 vector as a control, CL1‐0shControl, and its GR‐knockdown derivative, CL1‐0shΔGR, to evaluate differential protein level alteration and redox regulation of these two cell lines. We identified 34 spots that exhibited marked changes in intensities, and 13 proteins showing significant changes in thiol reactivity, in response to GR depletion. Several proteins involved in redox regulation, calcium signaling, cytoskeleton regulation, and protein folding showed significant changes in expression, whereas proteins involved in redox regulation, protein folding, and glycolysis displayed changes in thiol reactivity. Interestingly, GR knockdown induces peroxiredoxin‐1 overexpression in the air‐exposed tissue and high oxygen consuming tissue such as cornea and liver, but not in the low oxygen consuming tissues such as breast and uterine. In summary, we used a comprehensive lung adenocarcinoma based proteomic approach for identifying GR‐modulated protein expression alteration and redox modification. Based on our research, this is the first comprehensive proteomic and redox‐proteomic analysis used to investigate the role of GR in a mammalian cell model.  相似文献   

3.
Recently, applications of hyaluronic acid (HA) as a biomaterial were investigated. However, the weak structure of HA gel and the effects of using cross‐linker raised concerns during in vivo resolution. In this study, we investigated the method to solve these two problems using physical cross‐linking and compositing with poly(vinyl alcohol) (PVA). Various weight ratios of HA and PVA solutions were mixed, adjustment of pH to 1.8 using HCl then used to fabricate HA‐PVA cryo‐gel by freezing‐thawing. Young's modulus of the prepared gel rose with the increase of both HA and PVA concentrations or either one of them. We estimated that HA and PVA have exhibited these mechanical properties due to forming a double network. HA‐PVA gel showed kinetic friction force of approximately 10 times of PVA gel, while water contact angle and protein adsorption of HA‐PVA gels were remarkably decreased. The properties of the prepared gel suggest that it can be used for postoperative adhesion prevention applications.  相似文献   

4.
Identification of specific protein markers for colorectal cancer (CRC) could provide a basis for its early diagnosis and detection, as well as clues to the molecular mechanisms governing cancer progression. In the present study, 2‐D DIGE coupled with MS was used to screen for biomarker candidates in the serum proteome of ten human CRC samples and ten healthy control samples. After pooling identical amounts of serum proteins (based on total protein concentration), albumin/IgG was depleted under partially denaturing conditions. Subsequently, the serum samples were labeled with three different CyDyes, and separated by 2‐D DIGE. After analysis with the biological variation analysis module of the DeCyder software, only three spots were found to be significantly elevated in all patient groups (with ratios from 1.52 to 9.08), whereas five spots were significantly down‐regulated in patients (with ratios from ?1.23 to ?10.21) (t‐test; p<0.05). Finally, two potential biomarkers, Transaldolase 1 and thyroid receptor interactor, were chosen for validation and analysis by ELISA with the serum of 30 CRC patients and 30 healthy controls. The serum levels of the two proteins correlated well with the 2‐D DIGE results. Thus, 2‐D DIGE approaches show great promise for biomarker discovery in CRC.  相似文献   

5.
The efficient tumor targeting drug carrier was designed by bioconjugation of folic acid to β‐cyclodextrin through a polyamine cationic spacer. The characterization and inclusion complexation behavior of the inclusion complex of hydrophobic drug scutellarin with folic acid‐polyamine‐β‐cyclodextrin were investigated in both solution and solid state by means of phase‐solubility, nuclear magnetic resonance, X‐ray power diffraction, thermal gravimetric analysis, and scanning electron microscopy. Besides, the solubilization efficiency and antitumor activity of the inclusion complex were tested by saturated solution and MTT (Thiazole blue) method. Solubility and antitumor activity studies showed higher solubilizing ability and antitumor activity of the inclusion complex in comparison to free scutellarin. The folic acid‐polyamine‐β‐cyclodextrin that is presented may be promising active tumor‐targeting carrier candidates via folate mediation. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

6.
Blends were made by solution and melt‐mixing fatty‐acid‐modified dendrimers with various polyolefins. Small‐angle neutron scattering (SANS) was used to determine the miscibility of the blends. Poly(propylene imine) (PPI) dendrimers G1, G3, and G5 [DAB‐dendr‐(NH2)y] with y = 4, 16, and 64, were reacted with stearic acid or stearic acid‐d35 forming amide bonds. The modified dendrimers were then blended with high‐density polyethylene (HDPE), high‐density polyethylene‐d4 (HDPE‐d4), low‐density polyethylene (LDPE), amorphous polypropylene (PP), or an ethylene–butylene copolymer (E‐co‐B). Limiting power law behavior shows that all of the blends are immiscible. It is likely that the dendrimers form a second phase, being finely dispersed, but thermodynamically immiscible. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 95–100, 2000  相似文献   

7.
The formulation of organic–inorganic polymer composites can be used to enhance selected properties, such as susceptibility to microbial attack, thermal stability, mechanical strength and water sorption capability. Accordingly, a series of alginic acid–silica hydrogel films was prepared for testing as protective coating materials for PTFE osmotic distillation membranes. Unprotected hydrophobic membranes are subject to wet-out when contacted by surface-active agents, such as oils and detergents. Films containing 5, 10, 15 and 20 wt.% silica, with and without the addition of glycerol for plasticisation, moisturisation and silica dispersion, were characterised using scanning electron microscopy, X-ray diffraction, differential scanning calorimetry, mechanical strength measurements, and water-swelling measurements. Composites prepared with glycerol addition had better thermal stability, mechanical strength and water sorption capability than those prepared without glycerol addition. Uncoated membranes and membranes coated with composites prepared with glycerol addition were tested for OD performance and resistance to surface-active agents using pure water, orange oil (limonene)–water mixtures, and sodium dodecylbenzene sulfonate detergent solutions. Uncoated membranes showed immediate hydrophobicity loss in the presence of orange oil and detergent. For coated membranes, no wet-out occurred over the 15 h duration of three consecutive 5 h OD trials using orange oil–water mixtures. In the case of detergent solutions, the coating afforded protection to the membrane for 4–5 h. In a separate trial, no wet-out occurred when the coated side of the membrane was placed in contact with 1.2 wt.% orange oil for 72 h.  相似文献   

8.
Naturally occurring oleic and undecylenic acids were used as raw materials for the synthesis of novel polyurethanes (PUs). The application of environmentally friendly thiol‐ene additions to 10‐undecenoate and oleate derivatives was studied with the goal of obtaining renewable diols. The resulting monomers were then polymerized with 4,4′‐methylenebis (phenylisocyanate), in N,N‐dimethylformamide solution using tin (II) 2‐ethylhexanoate as catalyst, to produce the corresponding thermoplastic PUs (TPUs). Also, ultrasound irradiation has been tested to improve the synthesis of PU. Under these conditions, TPUs were obtained in high yields (80–99%) with weight‐average molecular weights in the 36–83 kDa range. The chemical structures of PUs were assessed by FTIR and NMR spectroscopy. The thermal and mechanical properties of the synthesized TPUs have been studied and they showed a clear dependence on the structure of the parent diol. MTT test was carried out to asses the potential cytotoxicity of the prepared PUs, indicating no cytotoxic response. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011  相似文献   

9.
Unprotected exo,exo‐5‐norbornene‐2,3‐dicarboxylic acid and exo,exo‐7‐oxa‐5‐norbornene‐2,3‐dicarboxylic acid were polymerized via ring‐opening metathesis polymerization. This reaction yielded polymers with molecular weights (Mn from GPC) ranging from 31 to 242 kg/mol and polydispersity indices between 1.05 and 1.12, using Grubbs' third generation catalyst. The water solubility as a function of pH value of the polymers was investigated by dynamic light scattering (DLS). DLS and acid‐base titration revealed that the oxanorbornene polymer was water soluble over a wider pH range than its norbornene analog. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1266–1273, 2009  相似文献   

10.
Amino acid‐derived novel norbornene derivatives, N,N′‐(endo‐bicyclo[2.2.1] hept‐5‐en‐2,3‐diyldicarbonyl) bis‐L ‐alanine methyl ester (NBA), N,N′‐(endo‐bicyclo[2.2.1]hept‐5‐en‐2,3‐diyldicarbonyl) bis‐L ‐leucine methyl ester (NBL), N,N′‐(endo‐bicyclo[2.2.1]hept‐5‐en‐2,3‐diyldicarbonyl) bis‐L ‐phenylalanine methyl ester (NBF) were synthesized and polymerized using the Grubbs 2nd generation ruthenium (Ru) catalyst. Although NBA, NBL, and NBF did not undergo homopolymerization, they underwent copolymerization with norbornene (NB) to give the copolymers with Mn ranging from 5200 to 38,100. The maximum incorporation ratio of the amino acid‐based unit was 9%, and the cis contents of the main chain were 54–66%. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5337–5343, 2006  相似文献   

11.
A method based on poly (methacrylic acid‐co‐ethylene glycol dimethacrylate) monolith microextraction and octadecylphosphonic acid‐modified zirconia‐coated CEC followed by field‐enhanced sample injection preconcentration technique was proposed for sensitive CE‐UV analysis of six antidepressants (doxepin, clozapine, imipramine, paroxetine, fluoxetine and chlorimipramine) in human plasma and urine. A poly(methacrylic acid‐co‐ethylene glycol dimethacrylate) monolithic capillary column was introduced for the extraction of antidepressants from urine and plasma samples. The hydrophobic main chains and acidic pendant groups of the monolithic column make it a superior material for extraction of basic analytes from aqueous matrix. After extraction, the desorption solvent, which normally provided an excellent medium to ensure direct compatibility for field‐enhanced sample injection in CE, was analyzed by CE directly. By the use of alkylphosphonate‐modified zirconia‐coated CEC for separation of the basic compounds of antidepressants, high separation efficiency and resolution were achieved because that both hydrophobic interaction between analytes and alkylphosphonate‐modified zirconia coat and electrophoretic effect work on the separation of antidepressants. The best separation was achieved using a buffer composed of 0.3 M ammonium acetate (adjusted to pH 4.5 with 1 M acetic acid) and 35% ACN v/v, with a temperature and voltage of 20°C and 20 kV, respectively. By applying both preconcentration procedures, LODs of 11.4–51.5 and 3.7–17.0 μg/L were achieved for the six antidepressants in human plasma and urine, respectively. Excellent method of reproducibility was found over a linear range of 50–5000 μg/L in plasma and urine sample.  相似文献   

12.
This article reviews recent developments in the polymerization of α‐amino acid‐ N‐carboxyanhydrides (NCAs) to form polypeptides. Traditional methods used to polymerize these monomers are described, and limitations in the utility of these systems for the preparation of polypeptides with controlled molecular weights and narrow molecular weight distributions are discussed. The development of transition‐metal‐based initiators, which activate the monomers to form covalent active species, permits the formation of polypeptides via the living polymerization of NCAs. In these systems, polymer molecular weights are controlled by monomer‐to‐initiator stoichiometry, polydispersities are low, and block copolypeptides can be prepared. The scope and limitations of these initiators and their key features and mode of operation are described in detail in this highlight. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3011–3018, 2000  相似文献   

13.
Photocrosslinked hyaluronic acid/poly(vinyl alcohol)‐styrylpyridinium (HA/PVA‐SbQ) hydrogels were synthesized for controlled antitumor drug delivery. The photocrosslinking reaction was rapid, and the time required for completely converting into the insoluble hydrogels was less than 500 s on exposure to 5 mW/cm2 UV light irradiation. The resulting hydrogels exhibited sensitivity to the pH value of the surrounding environment. Scanning electron microscopic analysis revealed that the morphology and the pore size of the hydrogels could be controlled by changing the ratio of HA and PVA‐SbQ in the formulations. Paclitaxel (PTX)‐loaded hydrogel could also be formed rapidly by UV irradiation of a mixed solution of HA/PVA‐SbQ and PTX. Release profiles of PTX from the hydrogels showed pH‐dependent and sustained manner. Moreover, our data revealed that PTX released from the HA hydrogels remained biologically active and had the capability to kill cancer cells. In contrast, control groups of HA hydrogels without PTX did not exhibit any cytotoxicity. This study demonstrates the feasibility of using HA‐based hydrogels as a potential carrier for chemotherapeutic drugs for cancer treatments. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012  相似文献   

14.
Decomposition processes of organoarsenic compounds significantly influence arsenic cycles in aquatic environments, and such processes depend on bacterial activity. However, the bacterial characteristics in these environments are obscure. Accordingly, we observed seasonal variations of arsenic species and the bacterial population decomposing dimethylarsinic acid (DMAA) in Lake Kahokugata from April 2002 to January 2003. Monitoring of bacterial biomass involving DMAA decomposition using the most probable number procedure showed that the bacterial cell densities ranged from 36 to 3600 ml?1. On the other hand, methylated arsenic was not detected during the experimental period, although the inorganic arsenic concentration was over 4 nM . This suggests that bacteria remineralized methylated arsenic species to inorganic arsenic. Furthermore, the composition of bacterial communities involving DMAA decomposition was examined by restriction‐fragment‐length polymorphism analysis of the 16S rDNA nucleotide. As a result, a total of 49 isolates were classified into 10 type groups, and 32 of these isolates belonged to three dominant type groups. Phylogenetic analysis using 16S rDNA partial sequences (ca 320 bp) suggests that the representative isolates of the dominant type groups are specific to the summer or winter season. Moreover, as a result of the culture experiments to examine DMAA decomposition activity, the representative isolates decomposed 1 µM DMAA at a decomposition percentage of below 80%. In conclusion, some bacterial communities in a specific season can decompose DMAA to varying degrees, contributing to the annual cycle of arsenic species. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

15.
Two types of three‐arm and four‐arm, star‐shaped poly(D,L ‐lactic acid‐alt‐glycolic acid)‐b‐poly(L ‐lactic acid) (D,L ‐PLGA50‐b‐PLLA) were successfully synthesized via the sequential ring‐opening polymerization of D,L ‐3‐methylglycolide (MG) and L ‐lactide (L ‐LA) with a multifunctional initiator, such as trimethylolpropane and pentaerythritol, and stannous octoate (SnOct2) as a catalyst. Star‐shaped, hydroxy‐terminated poly(D,L ‐lactic acid‐alt‐glycolic acid) (D,L ‐PLGA50) obtained from the polymerization of MG was used as a macroinitiator to initiate the block polymerization of L ‐LA with the SnOct2 catalyst in bulk at 130 °C. For the polymerization of L ‐LA with the three‐arm, star‐shaped D,L ‐PLGA50 macroinitiator (number‐average molecular weight = 6800) and the SnOct2 catalyst, the molecular weight of the resulting D,L ‐PLGA50‐b‐PLLA polymer linearly increased from 12,600 to 27,400 with the increasing molar ratio (1:1 to 3:1) of L ‐LA to MG, and the molecular weight distribution was rather narrow (weight‐average molecular weight/number‐average molecular weight = 1.09–1.15). The 1H NMR spectrum of the D,L ‐PLGA50‐b‐PLLA block copolymer showed that the molecular weight and unit composition of the block copolymer were controlled by the molar ratio of L ‐LA to the macroinitiator. The 13C NMR spectrum of the block copolymer clearly showed its diblock structures, that is, D,L ‐PLGA50 as the first block and poly(L ‐lactic acid) as the second block. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 409–415, 2002  相似文献   

16.
A significant correlation has been shown to exist between the interfacial tension of polymer pairs and their acid‐base pair interaction. The relationship is inverse, with interfacial tensions decreasing as acid‐base interactions increase. Interfacial tensions, frequently used as an indicator of polymer compatibility, were measured by the breaking thread method at temperatures in the vicinity of 200 °C. Acid‐base pair interaction values were measured by inverse gas chromatography over wide temperature ranges. The observed correlation confirms the important contribution made by short‐range, acid‐base interactions to the observed value of interfacial tension and supports the prediction of equations based on fundamental definitions of surface forces. A collateral finding of this work is the decrease of acid‐base functionality with rising temperature for all polymers studied. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 2096–2104, 2000  相似文献   

17.
Hyaluronic acid nanogel (HyA‐AT) is a redox sensitive crosslinkable nanogel, obtained through the conjugation of a thiolated hydrophobic molecule to the hyaluronic acid chain. Engineered nanogel was studied for its biocompatibility, including immunocompatibility and hemocompatability. The nanogel did not compromise the metabolic activity or cellular membrane integrity of 3T3, microvascular endothelial cells, and RAW 264.7 cell lines, as determined by the 3‐[4,5‐dimethylthiazol‐2‐yl]‐2,5‐diphenyl tetrazolium bromide and lactate dehydrogenase release assays. Also, we didn't observe any apoptotic effect on these cell lines through the Annexin V‐FITC test. Furthermore, the nanogel cell internalization was analyzed using murine bone marrow derived macrophages, and the in vivo and ex vivo biodistribution of the Cy5.5 labeled nanogel was monitored using a non‐invasive near‐infrared fluorescence imaging system. The HyA‐AT nanogel exhibits fairly a long half‐live in the blood stream, thus showing potential for drug delivery applications.

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18.
Phosphoric acid (PA)‐doped m‐polybenzimidazole (PBI) membranes used in high temperature fuel cells and hydrogen pumps were prepared by a conventional imbibing process and a sol–gel fabrication process. A comparative study was conducted to investigate the critical properties of PA doping levels, ionic conductivities, mechanical properties, and molecular ordering. This systematic study found that sol–gel PA‐doped m‐PBI membranes were able to absorb higher acid doping levels and to achieve higher ionic conductivities than conventionally imbibed membranes when treated in an equivalent manner. Even at similar acid loadings, the sol–gel membranes exhibited higher ionic conductivities. Heat treatment of conventionally imbibed membranes with ≤29 wt % solids caused a significant reduction in mechanical properties; conversely, sol–gel membranes exhibited an enhancement in mechanical properties. From X‐ray structural studies and atomistic simulations, both conventionally imbibed and sol–gel membranes exhibited d‐spacings of 3.5 and 4.6 Å, which were tentatively attributed to parallel ring stacking and staggered side‐to‐side packing, respectively, of the imidazole rings in these aromatic heterocyclic polymers. An anisotropic staggered side‐to‐side chain packing present in the conventional membranes may be related to the reduction in mechanical properties. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Polym. Phys. 2014 , 52, 26–35  相似文献   

19.
The reactions of polylactic acid (PLA) oligomers and isocyanates (4,4′‐diphenylmethane diisocyanate and toluene diisocyanate) are reported. The effects of the reaction conditions, that is, the reaction time, reaction temperature, molar ratios, isocyanates, and catalyst, on the number‐average molecular weight (Mn ) are demonstrated. The optimum reaction conditions are determined by the synthesis of relatively high Mn PLA‐based linear polyurethanes. The structure of the polymer samples was investigated with dynamic light scattering, 1H NMR, IR, and matrix‐assisted laser‐desorption ionization time‐of‐flight mass spectroscopy (MALDI‐TOF MS). © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 2925–2933, 2000  相似文献   

20.
Our objective was to synthesize and evaluate lactic acid‐ and carbonate‐based biodegradable core‐ and core‐corona crosslinkable copolymers for anticancer drug delivery. Methoxy poly(ethylene glycol)‐b‐poly(carbonate‐co‐lactide‐co‐5‐methyl‐5‐allyloxycarbonyl‐1,3‐dioxane‐2‐one) [mPEG‐b‐P(CB‐co‐LA‐co‐MAC)] and methoxy poly(ethylene glycol)‐b‐poly(acryloyl carbonate)‐b‐poly(carbonate‐co‐lactide) [mPEG‐b‐PMAC‐b‐P(CB‐co‐LA)] copolymers were synthesized by ring‐opening polymerization of LA, CB, and MAC using mPEG as an macroinitiator and 1,8‐diazabicycloundec‐7‐ene as a catalyst. These amphiphilic copolymers which exhibited low polydispersity and critical micelle concentration values (0.8–1 mg/L) were used to prepare micelles with or without drug and stabilized by crosslinking via radical polymerization of double bonds introduced in the core and interface to improve stability. mPEG114b‐P(CB8co‐LA35co‐MAC2.5) had a higher drug encapsulation efficiency (78.72% ± 0.15%) compared to mPEG114b‐PMAC2.5b‐P(CB9co‐LA39) (20.29% ± 0.11%).1H NMR and IR spectroscopy confirmed successful crosslinking (~70%) while light scattering and transmission electron microscopy were used to determine micelle size and morphology. Crosslinked micelles demonstrated enhanced stability against extensive dilution with aqueous solvents and in the presence of physiological simulating serum concentration. Furthermore, bicalutamide‐loaded crosslinked micelles were more potent compared to non‐crosslinked micelles in inhibiting LNCaP cell proliferation irrespective of polymer type. Finally, these results suggest crosslinked micelles to be promising drug delivery vehicles for chemotherapy. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013  相似文献   

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