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Sample records for cells selectively blocks

  1. Blocked Randomization with Randomly Selected Block Sizes

    Directory of Open Access Journals (Sweden)

    Jimmy Efird

    2010-12-01

    Full Text Available When planning a randomized clinical trial, careful consideration must be given to how participants are selected for various arms of a study. Selection and accidental bias may occur when participants are not assigned to study groups with equal probability. A simple random allocation scheme is a process by which each participant has equal likelihood of being assigned to treatment versus referent groups. However, by chance an unequal number of individuals may be assigned to each arm of the study and thus decrease the power to detect statistically significant differences between groups. Block randomization is a commonly used technique in clinical trial design to reduce bias and achieve balance in the allocation of participants to treatment arms, especially when the sample size is small. This method increases the probability that each arm will contain an equal number of individuals by sequencing participant assignments by block. Yet still, the allocation process may be predictable, for example, when the investigator is not blind and the block size is fixed. This paper provides an overview of blocked randomization and illustrates how to avoid selection bias by using random block sizes.

  2. Blocked randomization with randomly selected block sizes.

    Science.gov (United States)

    Efird, Jimmy

    2011-01-01

    When planning a randomized clinical trial, careful consideration must be given to how participants are selected for various arms of a study. Selection and accidental bias may occur when participants are not assigned to study groups with equal probability. A simple random allocation scheme is a process by which each participant has equal likelihood of being assigned to treatment versus referent groups. However, by chance an unequal number of individuals may be assigned to each arm of the study and thus decrease the power to detect statistically significant differences between groups. Block randomization is a commonly used technique in clinical trial design to reduce bias and achieve balance in the allocation of participants to treatment arms, especially when the sample size is small. This method increases the probability that each arm will contain an equal number of individuals by sequencing participant assignments by block. Yet still, the allocation process may be predictable, for example, when the investigator is not blind and the block size is fixed. This paper provides an overview of blocked randomization and illustrates how to avoid selection bias by using random block sizes. PMID:21318011

  3. Cells bearing chromosome aberrations lacking one telomere are selectively blocked at the G2/M checkpoint

    International Nuclear Information System (INIS)

    Cell cycle checkpoints are part of the cellular mechanisms to maintain genomic integrity. After ionizing radiation exposure, the cells can show delay or arrest in their progression through the cell cycle, as well as an activation of the DNA repair machinery in order to reduce the damage. The G2/M checkpoint prevents G2 cells entering mitosis until the DNA damage has been reduced. The present study evaluates which G0 radiation-induced chromosome aberrations are negatively selected in the G2/M checkpoint. For this purpose, peripheral blood samples were irradiated at 1 and 3 Gy of γ-rays, and lymphocytes were cultured for 48 h. Calyculin-A and Colcemid were used to analyze, in the same slide, cells in G2 and M. Chromosome spreads were consecutively analyzed by solid stain, pancentromeric and pantelomeric FISH and mFISH. The results show that the frequency of incomplete chromosome elements, those lacking a telomeric signal at one end, decreases abruptly from G2 to M. This indicates that cells with incomplete chromosome elements can progress from G0 to G2, but at the G2/M checkpoint suffer a strong negative selection.

  4. Cells bearing chromosome aberrations lacking one telomere are selectively blocked at the G2/M checkpoint

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, Pilar [Unitat de Biologia Cel.lular, Departament de Biologia Cel.lular, Fisiologia i Immunologia, Universitat Autonoma de Barcelona, 08193 Bellaterra (Spain); Barquinero, Joan Francesc [Unitat d' Antropologia Biologica, Departament de Biologia Animal, Biologia Vegetal i Ecologia, Universitat Autonoma de Barcelona, 08193 Bellaterra (Spain); Duran, Assumpta [Unitat de Biologia Cel.lular, Departament de Biologia Cel.lular, Fisiologia i Immunologia, Universitat Autonoma de Barcelona, 08193 Bellaterra (Spain); Caballin, Maria Rosa [Unitat d' Antropologia Biologica, Departament de Biologia Animal, Biologia Vegetal i Ecologia, Universitat Autonoma de Barcelona, 08193 Bellaterra (Spain); Ribas, Montserrat [Servei de Radiofisica i Radioproteccio de l' Hospital de la Santa Creu i Sant Pau, 08025 Barcelona (Spain); Barrios, Leonardo, E-mail: Lleonard.Barrios@uab.cat [Unitat de Biologia Cel.lular, Departament de Biologia Cel.lular, Fisiologia i Immunologia, Universitat Autonoma de Barcelona, 08193 Bellaterra (Spain)

    2009-11-02

    Cell cycle checkpoints are part of the cellular mechanisms to maintain genomic integrity. After ionizing radiation exposure, the cells can show delay or arrest in their progression through the cell cycle, as well as an activation of the DNA repair machinery in order to reduce the damage. The G2/M checkpoint prevents G2 cells entering mitosis until the DNA damage has been reduced. The present study evaluates which G0 radiation-induced chromosome aberrations are negatively selected in the G2/M checkpoint. For this purpose, peripheral blood samples were irradiated at 1 and 3 Gy of {gamma}-rays, and lymphocytes were cultured for 48 h. Calyculin-A and Colcemid were used to analyze, in the same slide, cells in G2 and M. Chromosome spreads were consecutively analyzed by solid stain, pancentromeric and pantelomeric FISH and mFISH. The results show that the frequency of incomplete chromosome elements, those lacking a telomeric signal at one end, decreases abruptly from G2 to M. This indicates that cells with incomplete chromosome elements can progress from G0 to G2, but at the G2/M checkpoint suffer a strong negative selection.

  5. Inhibition of T cell proliferation by selective block of Ca(2+)-activated K(+) channels

    DEFF Research Database (Denmark)

    Jensen, B S; Odum, Niels; Jorgensen, N K;

    1999-01-01

    T lymphocytes express a plethora of distinct ion channels that participate in the control of calcium homeostasis and signal transduction. Potassium channels play a critical role in the modulation of T cell calcium signaling, and the significance of the voltage-dependent K channel, Kv1.3, is well...... established. The recent cloning of the Ca(2+)-activated, intermediate-conductance K(+) channel (IK channel) has enabled a detailed investigation of the role of this highly Ca(2+)-sensitive K(+) channel in the calcium signaling and subsequent regulation of T cell proliferation. The role IK channels play in T...

  6. Metformin selectively targets cancer stem cells, and acts together with chemotherapy to block tumor growth and prolong remission

    OpenAIRE

    Hirsch, Heather A; Iliopoulos, Dimitrios; Tsichlis, Philip N.; Struhl, Kevin

    2009-01-01

    The cancer stem cell hypothesis suggests that, unlike most cancer cells within a tumor, cancer stem cells resist chemotherapeutic drugs and can regenerate the various cell types in the tumor, thereby causing relapse of the disease. Thus, drugs that selectively target cancer stem cells offer great promise for cancer treatment, particularly in combination with chemotherapy. Here, we show that low doses of metformin, a standard drug for diabetes, inhibits cellular transformation and selectively ...

  7. Cryptanalysis of Selected Block Ciphers

    DEFF Research Database (Denmark)

    Alkhzaimi, Hoda A.

    , pseudorandom number generators, and authenticated encryption designs. For this reason a multitude of initiatives over the years has been established to provide a secure and sound designs for block ciphers as in the calls for Data Encryption Standard (DES) and Advanced Encryption Standard (AES), lightweight...... ciphers initiatives, and the Competition for Authenticated Encryption: Security, Applicability, and Robustness (CAESAR). In this thesis, we first present cryptanalytic results on different ciphers. We propose attack named the Invariant Subspace Attack. It is utilized to break the full block cipher...... as truncated differentials. In addition to that, we also investigate the security of SIMON against different linear cryptanalysis methods, i.e., classic linear,and linear hull attacks. we present a connection between linear characteristic and differential characteristic, multiple linear and differential...

  8. Blocking a selective association in pigeons.

    OpenAIRE

    Weiss, S J; Panlilio, L V

    1999-01-01

    Experiment 1 demonstrated for the first time a stimulus-reinforcer interaction in pigeons trained with free-operant multiple schedules of reinforcement. Pigeons that treadle pressed in the presence of a tone-light (TL) compound for food exhibited primarily visual stimulus control on a stimulus-element test, whereas pigeons that avoided shock in TL exhibited auditory control. In Experiment 2, this selective association was blocked in pigeons pretrained with the biologically contingency-disadva...

  9. Tofogliflozin, A Highly Selective Inhibitor of SGLT2 Blocks Proinflammatory and Proapoptotic Effects of Glucose Overload on Proximal Tubular Cells Partly by Suppressing Oxidative Stress Generation.

    Science.gov (United States)

    Ishibashi, Y; Matsui, T; Yamagishi, S

    2016-03-01

    Ninety percent of glucose filtered by the glomerulus is reabsorbed by a sodium-glucose cotransporter 2 (SGLT2), which is mainly expressed on S1 and S2 segment of renal proximal tubules. Since SGLT-2-mediated glucose reabsorption is increased under diabetic conditions, selective inhibition of SGLT2 is a potential therapeutic target for the treatment of diabetes. We have recently shown that an inhibitor of SGLT2 has anti-inflammatory and antifibrotic effects on experimental diabetic nephropathy partly by suppressing advanced glycation end products formation and oxidative stress generation in the kidney. However, the direct effects of SGLT2 inhibitor on tubular cell damage remain unclear. In this study, we investigated the effects of tofogliflozin, a highly selective inhibitor of SGLT2 on oxidative stress generation, inflammatory and proapoptotic reactions in cultured human proximal tubular cells exposed to high glucose. Tofogliflozin dose-dependently suppressed glucose entry into tubular cells. High glucose exposure (30 mM) for 4 and 24 h significantly increased oxidative stress generation in tubular cells, which were suppressed by the treatment of tofogliflozin or an antioxidant N-acetylcysteine (NAC). Monocyte chemoattractant protein-1 (MCP-1) gene expression and apoptotic cell death were induced by 4 h- and 8 day-exposure to high glucose, respectively, both of which were also blocked by tofogliflozin or NAC. The present study suggests that SGLT2-mediated glucose entry into tubular cells could stimulate oxidative stress and evoke inflammatory and proapoptotic reactions in this cell type. Blockade of glucose reabsorption in tubular cells by SGLT2 inhibitor might exert beneficial effects on tubulointerstitial damage in diabetic nephropathy. PMID:26158396

  10. Building-block selectivity of polyketide synthases.

    Science.gov (United States)

    Liou, Grace F; Khosla, Chaitan

    2003-04-01

    For the past decade, polyketide synthases have presented an exciting paradigm for the controlled manipulation of complex natural product structure. These multifunctional enzymes catalyze the biosynthesis of polyketide natural products by stepwise condensation and modification of metabolically derived building blocks. In particular, regioselective modification of polyketide structure is possible by alterations in either intracellular acyl-CoA pools or, more commonly, by manipulation of acyl transferases that act as the primary gatekeepers for building blocks.

  11. Worldwide population genetic analysis and natural selection in the Plasmodium vivax Generative Cell Specific 1 (PvGCS1) as a transmission-blocking vaccine candidate.

    Science.gov (United States)

    Mehrizi, Akram Abouie; Dodangeh, Fatemeh; Zakeri, Sedigheh; Djadid, Navid Dinparast

    2016-09-01

    GENERATIVE CELL SPECIFIC 1 (GCS1) is one of the Transmission Blocking Vaccine (TBV) candidate antigens, which is expressed on the surface of male gametocytes and gametes of Plasmodium species. Since antigenic diversity could inhibit the successful development of a malaria vaccine, it is crucial to determine the diversity of gcs1 gene in global malaria-endemic areas. Therefore, gene diversity and selection of gcs1 gene were analyzed in Iranian Plasmodium vivax isolates (n=52) and compared with the corresponding sequences from worldwide clinical P. vivax isolates available in PlasmoDB database. Totally 12 SNPs were detected in the pvgcs1 sequences as compared to Sal-1 sequence. Five out of 12 SNPs including three synonymous (T797C, G1559A, and G1667T) and two amino acid replacements (Y133S and Q634P) were detected in Iranian pvgcs1 sequences. According to four amino acid replacements (Y133S, N575S, Q634P and D637N) observed in all world PvGCS1 sequences, totally 5 PvGCS1 haplotypes were detected in the world, that three of them observed in Iranian isolates including the PvGCS-A (133S/634Q, 92.3%), PvGCS-B (133Y/634Q, 5.8%), and PvGCS-C (133S/634P, 1.9%). The overall nucleotide diversity (π) for all 52 sequences of Iranian pvgcs1 gene was 0.00018±0.00006, and the value of dN-dS (-0.00031) were negative, however, it was not statistically significant. In comparison with global isolates, Iranian and PNG pvgcs1 sequences had the lowest nucleotide and haplotype diversity, while the highest nucleotide and haplotype diversity was observed in China population. Moreover, epitope prediction in this antigen showed that all B-cell epitopes were located in conserved regions. However, Q634P (in one Iranian isolate) and D637N (observed in Thailand, China, Vietnam and North Korea) mutations are involved in predicted IURs. The obtained results in this study could be used in development of PvGCS1 based malaria vaccine. PMID:27180894

  12. Electric Field Induced Selective Disordering in Lamellar Block Copolymers

    Energy Technology Data Exchange (ETDEWEB)

    Ruppel, Markus A [ORNL; Pester, Christian W [ORNL; Langner, Karol M [Leiden Institute of Chemistry, Leiden University, The Netherlands; Sevink, Geert [Leiden Institute of Chemistry, Leiden University, The Netherlands; Schoberth, Heiko [University of Bayreuth; Schmidt, Kristin [ORNL; Urban, Volker S [ORNL; Mays, Jimmy [ORNL; Boker, Alexander [RWTH Aachen University

    2013-01-01

    External electric fields align nanostructured block copolymers by either rotation of grains or nucleation and growth depending on how strongly the chemically distinct block copolymer components are segregated. In close vicinity to the orderdisorder transition, theory and simulations suggest a third mechanism: selective disordering. We present a time-resolved small-angle X-ray scattering study that demonstrates how an electric field can indeed selectively disintegrate ill-aligned lamellae in a lyotropic block copolymer solution, while lamellae with interfaces oriented parallel to the applied field prevail. The present study adds an additional mechanism to the experimentally corroborated suite of mechanistic pathways, by which nanostructured block copolymers can align with an electric field. Our results further unveil the benefit of electric field assisted annealing for mitigating orientational disorder and topological defects in block copolymer mesophases, both in close vicinity to the orderdisorder transition and well below it.

  13. Selective Absorption Mechanism for the Maintenance of Blocking

    Science.gov (United States)

    Yamazaki, Akira; Itoh, Hisanori

    2010-05-01

    Atmospheric blocking is one of the most influential phenomena in global atmospheric environments. The understanding of its dynamical processes is important to clarify weather extremes and the stratosphere-troposphere coupling and to extend forecast periods. In the dynamics of blocking, especially, its maintenance mechanism has been a stimulating topic for many meteorologists. About the maintenance mechanism of blocking, Shutts (1983) evaluated the effect of synoptic eddies in his numerical model and proposed the Eddy Straining Mechanism (hereafter, referred to as ESM). Using simple numerical models, he demonstrated that synoptic eddies strained in the north-south direction by blocking provide negative/positive vorticity to a blocking high/low and this vorticity forcing, i.e., the second-order flow maintains the blocking dipole structure against dissipation. Some pieces of evidence, however have shown that the ESM does not work well in several real cases of the block maintenance. For example, Arai and Mukougawa (2002) performed a similar experiment to Shutts (1983) and indicated the strong sensitivity of the ESM against a small meridional shift of the stormtrack (strictly speaking, wavemaker), or a small change of the size of high-frequency eddies. This is a very adverse constraint in the real atmosphere because the relative positions of blocking to the stormtrack tend to fluctuate from case to case so that they do not necessarily exist in the same latitude band. Thus, we propose a more realistic mechanism of the block maintenance named as the Selective Absorption Mechanism (hereafter referred to as SAM), in which a blocking anticyclone selectively and exclusively absorbs synoptic anticyclones. This mechanism is essentially the same mechanism as the Fujiwhara effect, which qualitatively explains that binary eddies with the same polarity merge and eddies with the opposite polarity separate. In this study, we verify the effectiveness of the SAM by observational

  14. Carbamate-linked lactose: design of clusters and evidence for selectivity to block binding of human lectins to (neo)glycoproteins with increasing degree of branching and to tumor cells.

    Science.gov (United States)

    André, Sabine; Specker, Daniel; Bovin, Nicolai V; Lensch, Martin; Kaltner, Herbert; Gabius, Hans-Joachim; Wittmann, Valentin

    2009-09-01

    Various pathogenic processes are driven by protein(lectin)-glycan interactions, especially involving beta-galactosides at branch ends of cellular glycans. These emerging insights fuel the interest to design potent inhibitors to block lectins. As a step toward this aim, we prepared a series of ten mono- to tetravalent glycocompounds with lactose as a common headgroup. To obtain activated carbonate for ensuing carbamate formation, conditions for the facile synthesis of pure isomers from anomerically unprotected lactose were identified. To probe for the often encountered intrafamily diversity of human lectins, we selected representative members from the three subgroups of adhesion/growth-regulatory galectins as receptors. Diversity of the glycan display was accounted for by using four (neo)glycoproteins with different degrees of glycan branching as matrices in solid-phase assays. Cases of increased inhibitory potency of lactose clusters compared to free lactose were revealed. Extent of relative inhibition was not directly associated with valency in the glycocompound and depended on the lectin type. Of note for screening protocols, efficacy of blocking appeared to decrease with increased degree of glycan branching in matrix glycoproteins. Binding to tumor cells was impaired with selectivity for galectins-3 and -4. Representative compounds did not impair growth of carcinoma cells up to a concentration of 5 mM of lactose moieties (valence-corrected value) per assay. The reported bioactivity and the delineation of its modulation by structural parameters of lectins and glycans set instructive examples for the further design of selective inhibitors and assay procedures. PMID:19715307

  15. User selection strategies for multiuser MIMO systems with block diagonalization

    Institute of Scientific and Technical Information of China (English)

    ZHOU Bei; XU Ning; WANG Ying; ZHANG Ping

    2008-01-01

    Block diagonalization (BD) is an efficient precodingtechnique that eliminates inter-user interference in downlinkmultiple-input multiple-output (MIMO) systems. User selectionstrategies applied to multiuser MIMO systems with BD areinvestigated in this article. To enhance the capacity of multiuserMIMO systems, an equivalent capacity maximum (ECM) userselection strategy is proposed with low computational complexity.Considering both the factors of channel correlations andchannel conditions, the proposed strategy can select a group ofusers to serve for maximizing the total throughput. Simulationresults indicate that, for various channel conditions, proposedECM strategy gains a better performance compared withtraditional user selection strategies, and achieves a near optimalthroughput as the exhaustive search.

  16. Two cell cycle blocks caused by iron chelation of neuroblastoma cells: separating cell cycle events associated with each block.

    Science.gov (United States)

    Siriwardana, Gamini; Seligman, Paul A

    2013-12-01

    Studies have presented evidence that besides the well described S phase block, treatment of cancer cell lines with the iron chelator deferrioxamine (DFO) also results in an earlier block in G1 phase. In this article, measurements of cell cycle regulatory proteins define this block at a very specific point in G1. DFO treatment results in markedly decreased cyclin A protein levels. Cyclin E levels that accumulate in early to mid-G1 are increased in cells treated with DFO as compared to the resting cells. The DFO S phase block is shown after cells are arrested at G1/S by (aphidicolin) then released into DFO. The same S phase block occurs with DFO treatment of a neuroblastoma cell line relatively resistant to the G1 DFO block. These experiments clearly differentiate the S phase DFO block from the earlier block pinpointed to a point in mid-G1, before G1/S when cyclin E protein increases but before increased cyclin A synthesis. Apoptosis was observed in cells inhibited by DFO at both cell cycle arrest points. PMID:24744856

  17. Two cell cycle blocks caused by iron chelation of neuroblastoma cells: separating cell cycle events associated with each block.

    Science.gov (United States)

    Siriwardana, Gamini; Seligman, Paul A

    2013-12-01

    Studies have presented evidence that besides the well described S phase block, treatment of cancer cell lines with the iron chelator deferrioxamine (DFO) also results in an earlier block in G1 phase. In this article, measurements of cell cycle regulatory proteins define this block at a very specific point in G1. DFO treatment results in markedly decreased cyclin A protein levels. Cyclin E levels that accumulate in early to mid-G1 are increased in cells treated with DFO as compared to the resting cells. The DFO S phase block is shown after cells are arrested at G1/S by (aphidicolin) then released into DFO. The same S phase block occurs with DFO treatment of a neuroblastoma cell line relatively resistant to the G1 DFO block. These experiments clearly differentiate the S phase DFO block from the earlier block pinpointed to a point in mid-G1, before G1/S when cyclin E protein increases but before increased cyclin A synthesis. Apoptosis was observed in cells inhibited by DFO at both cell cycle arrest points.

  18. Inference for blocked randomization under a selection bias model.

    Science.gov (United States)

    Kennes, Lieven N; Rosenberger, William F; Hilgers, Ralf-Dieter

    2015-12-01

    We provide an asymptotic test to analyze randomized clinical trials that may be subject to selection bias. For normally distributed responses, and under permuted block randomization, we derive a likelihood ratio test of the treatment effect under a selection bias model. A likelihood ratio test of the presence of selection bias arises from the same formulation. We prove that the test is asymptotically chi-square on one degree of freedom. These results correlate well with the likelihood ratio test of Ivanova et al. (2005, Statistics in Medicine 24, 1537-1546) for binary responses, for which they established by simulation that the asymptotic distribution is chi-square. Simulations also show that the test is robust to departures from normality and under another randomization procedure. We illustrate the test by reanalyzing a clinical trial on retinal detachment. PMID:26099068

  19. A fast block mode selection approach for H. Visual coding

    Institute of Scientific and Technical Information of China (English)

    LIN Wei-yao; Fang Xiang-zhong; HUANG Xiu-chao; LI Dian; LIU Xiao-feng

    2006-01-01

    In this paper,a new fast mode-selection approach is proposed.This algorithm combines the proposed approaches of mode pre-decision and precise large-small mode decision,by selecting the best mode efficiently.Experimental results show that the proposed approach can reduce the computational cost of full search and fast multi-block motion estimation by 8% and 45%,respectively,with similar visual quality and bit rate.The proposed algorithm also reduces by 75% the computational cost of the large-small mode isolation algorithm for low-motion sequence coding,and with 0.06 PSNR gain and 3.7% reduction in bit rate.

  20. Ultrasound guided selective cervical nerve root block and superficial cervical plexus block for surgeries on the clavicle

    Directory of Open Access Journals (Sweden)

    Harsha Shanthanna

    2014-01-01

    Full Text Available We report the anaesthetic management of two cases involving surgeries on the clavicle, performed under superficial cervical plexus block and selective C5 nerve root block under ultrasound (US guidance, along with general anaesthesia. Regional analgesia for clavicular surgeries is challenging. Our patients also had significant comorbidities necessitating individualised approach. The first patient had a history of emphysema, obesity, and was allergic to morphine and hydromorphone. The second patient had clavicular arthritis and pain due to previous surgeries. He had a history of smoking, Stevens-Johnson syndrome, along with daily marijuana and prescription opioid use. Both patients had an effective regional block and required minimal supplementation of analgesia, both being discharged on the same day. Interscalene block with its associated risks and complications may not be suitable for every patient. This report highlights the importance of selective regional blockade and also the use of US guidance for an effective and safe block.

  1. ANALYSIS OF CELL BLOCK VS . CONVENTIONAL SMEAR IN FLUID CYTOLOGY

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    Jyotsna

    2015-09-01

    Full Text Available BACKGROUND: The cytological examination of aspirates of serous effusions is a routinely accepted , simple , safe and minimally invasive technique . Diagnosis in this investigation , especially in malignant effusions , helps in staging , prognosis and management of the patients . AIMS: To assess the utility and sensitivity of cell block method over conventional smear technique in cytodiagnosis of the serous effusions . METHODS: A total of 72 fluid specimens were subjected to simultaneous processing by conventional s mear and cell block technique . Each fluid specimen was divided into two equal parts and results compared for cellularity , cell architecture , cytoplasmic and nuclear features . Cell blocks were prepared using modified cell block technique using alcohol forma lin fixative . RESULTS: The utility of cell block technique in diagnosing malignant effusions is highly significant as compared to the conventional smear technique . Also , the technique using alcohol formalin fixative is simple , safe and these chemicals are routinely used in laboratory . CONCLUSION: Cell block technique is superior to conventional smear technique , especially for malignant effusions . It gives more information about the architectural arrangement and the likely source of primary . More important is that diagnostic material in cell blocks is available for special studies for . I mmunohistochemistry which can further supplement our knowledge about the primary source of metastasis

  2. Block Textured a-Si:H Solar Cell

    Directory of Open Access Journals (Sweden)

    Seung Jae Moon

    2014-01-01

    Full Text Available A series of etching experiments on light trapping structure have been carried out by glass etching. The block structure provides long light traveling path and a constant distance between the cathode and anode electrodes regardless of the block height, which results in higher efficiency of the block textured solar cell. In terms of etching profile of the glass substrate, the addition of NH4F resulted in the smooth and clean etching profile, and the steep slope of the block was obtained by optimizing the composition of etching solution. For a higher HF concentration, a more graded slope was obtained and the addition of HNO3 and NH4F provided steep slope and clean etching profile. The effects of the block textured glass were verified by a comparison of the solar cell efficiency. For the textured solar cell, the surface was much rougher than that of the plain glass, which also contributes to the improvement of the efficiency. We accomplished block shaped light trapping structure for the first time by wet etching of the glass substrate, which enables the high efficiency thin film solar cell with the aid of the good step coverage deposition.

  3. M cell-depletion blocks oral prion disease pathogenesis.

    Science.gov (United States)

    Donaldson, D S; Kobayashi, A; Ohno, H; Yagita, H; Williams, I R; Mabbott, N A

    2012-03-01

    Many prion diseases are orally acquired. Our data show that after oral exposure, early prion replication upon follicular dendritic cells (FDC) in Peyer's patches is obligatory for the efficient spread of disease to the brain (termed neuroinvasion). For prions to replicate on FDC within Peyer's patches after ingestion of a contaminated meal, they must first cross the gut epithelium. However, the mechanism through which prions are conveyed into Peyer's patches is uncertain. Within the follicle-associated epithelium overlying Peyer's patches are microfold cells (M cells), unique epithelial cells specialized for the transcytosis of particles. We show that following M cell-depletion, early prion accumulation upon FDC in Peyer's patches is blocked. Furthermore, in the absence of M cells at the time of oral exposure, neuroinvasion and disease development are likewise blocked. These data suggest M cells are important sites of prion uptake from the gut lumen into Peyer's patches. PMID:22294048

  4. The Effect of Haplotype-Block Definitions on Inference of Haplotype-Block Structure and htSNPs Selection

    Institute of Scientific and Technical Information of China (English)

    KeyueDing; KaixinZhou; JingZhang; JoanneKnight; XuegongZhang; YanShen

    2005-01-01

    It has been recently suggested that the human genome is organized as a series of haplotype blocks, and efforts to create a genome-wide haplotype map are already underway. Several computational algorithms have been proposed to partition the genome. However, little is known about their behaviors in relation to the haplotype-block partitioning and haplotypetagging SNPs selection. Here, we present a systematic comparison of three classes of haplotype-block partition definitions, a diversity-based method, a linkage-disequilibrium (LD)-based method, and a recombination-based method.The data used were derived from a coalescent simulation under both a uniform recombination model and one that assumes recombination hotspots. There were considerable differences in haplotype information loss in the measure of entropy when the partition methods were compared under different population-genetics scenarios. Under both recombination models, the results from the LD-based definition and the recombination-based definition were more similar to each other than were the results from the diversity-based definition. This work demonstrates that when undertaking haplotype-based association mapping, the choice of haplotype-block definition and SNP selection requires careful consideration.

  5. DIAGNOSTIC UTILITY OF CELL BLOCKS IN THYROID ASPIRATES

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    Zarika

    2015-09-01

    Full Text Available BACKGROUND: Thyroid swellings are a common clinical presentation. The distribution of benign lesions from malignant lesions cannot be made by clinical judgment. The pathological lesions need morphological workup, Fine Needle Aspirations (FNA being one of the cornerstones. Its limitations are sample inadequacy, low cytomorphologic details and architectural insights with overlapping of cytological features . Cell block is a diagnostic method where material for morphologic evaluation is well recognized as it increases cellular yield, thus improves diagnostic accuracy. It provides excellent cytomorphologic details in concert with architectural insight with much more diagnostic efficacy, thus obviates repeat FNA. AIMS: To analyze the diagnostic utility of cell blocks on thyroid aspirates by taking the histopathological findings as the gold standard and statistically analyzed for diagnostic efficacy of cell block. MATERIALS AND METHOD: The study design was hospital based cross - sectional study. Ninety FNAC samples were taken and cell block was prepared u sing Tissue Thromboplastic method. Cell Block findings were analyzed by looking at the a rrangement of follicular cells size , acini, nuclear cytoplasmic characteristics, colloid, stroma, inflammatory cells, malignant cells, psammoma bodies, haemorrhage, necrosis, calcification, fibrosis, amyloid or any other relevant findings. RESULTS: Out of the 90 cases, 69 cases (76.67% were diagnosed as Non neoplastic lesions and 21cases (23.33% as Neoplastic. Of the Non - neoplastic cases, colloid goiter was the commonest, (64.44%. Among the Neoplastic lesions Follicular adenoma was the commonest (11.11%. Histopathologically, out of the 47 cases, Non - neoplastic lesions were 32 cases (68.09% and neoplastic lesions 15 cases (31.91%. Colloid goiter was the commonest thyroid lesion (53.19%. In Neoplastic lesions Follicular adenoma cases was the commonest (21.28%.There was 0 False Negative case and 2 cases of

  6. Investigation of parameter limit of selecting polymer flooding potential block at the Pubei Oilfield

    Science.gov (United States)

    Wang, Y. N.; Zhang, J. H.; Guan, D.; Liu, C.

    2016-08-01

    The Pubei oilfield belongs to the reservoir with low permeability and poor physical property. It has entered the late period of high water cut stage, so it needs polymer flooding to produce remaining oil. In order to pursue benefits and avoid risk, it is necessary to select potential block of polymer flooding by optimum parameters. In the paper, the limit of permeability for selecting potential block of polymer flooding is calculated by using both reservoir engineering method and economic analysis theory.

  7. Selective salpingography and recanalisation of blocked fallopian tubes.

    LENUS (Irish Health Repository)

    Allen, C

    2010-09-01

    Fallopian tubal disease is a common cause of subfertility. Reproductive surgery or assisted reproduction techniques such as in vitro fertilization (IVF) have been the main treatment options for patients with tubal disease in Ireland, although access to these treatments remains limited. We describe a case of pregnancy following selective salpingography and fallopian tube recanalisation.

  8. Therapeutic tumor-specific cell cycle block induced by methionine starvation in vivo.

    Science.gov (United States)

    Guo, H; Lishko, V K; Herrera, H; Groce, A; Kubota, T; Hoffman, R M

    1993-12-01

    The ability to induce a specific cell cycle block selectively in the tumor could have many uses in chemotherapy. In the present study we have achieved this goal of inducing a tumor-specific cell cycle block in vivo by depriving Yoshida sarcoma-bearing nude mice of dietary methionine. Further, we demonstrate that methionine depletion also causes the tumor to eventually regress. The antitumor effect of methionine depletion resulted in the extended survival of the tumor-bearing mice. The mice on the methionine-deprived diets maintained their body weight for the time period studied, indicating that tumor regression was not a function of body weight loss. The data reported here support future experiments utilizing methionine depletion as a target for tumor-selective cell cycle-dependent therapy.

  9. Phosphatidylinositol 3-kinase inhibitors block differentiation of skeletal muscle cells.

    Science.gov (United States)

    Kaliman, P; Viñals, F; Testar, X; Palacín, M; Zorzano, A

    1996-08-01

    Skeletal muscle differentiation involves myoblast alignment, elongation, and fusion into multinucleate myotubes, together with the induction of regulatory and structural muscle-specific genes. Here we show that two phosphatidylinositol 3-kinase inhibitors, LY294002 and wortmannin, blocked an essential step in the differentiation of two skeletal muscle cell models. Both inhibitors abolished the capacity of L6E9 myoblasts to form myotubes, without affecting myoblast proliferation, elongation, or alignment. Myogenic events like the induction of myogenin and of glucose carrier GLUT4 were also blocked and myoblasts could not exit the cell cycle, as measured by the lack of mRNA induction of p21 cyclin-dependent kinase inhibitor. Overexpresssion of MyoD in 10T1/2 cells was not sufficient to bypass the myogenic differentiation blockade by LY294002. Upon serum withdrawal, 10T1/2-MyoD cells formed myotubes and showed increased levels of myogenin and p21. In contrast, LY294002-treated cells exhibited none of these myogenic characteristics and maintained high levels of Id, a negative regulator of myogenesis. These data indicate that whereas phosphatidylinositol 3-kinase is not indispensable for cell proliferation or in the initial events of myoblast differentiation, i.e. elongation and alignment, it appears to be essential for terminal differentiation of muscle cells. PMID:8702591

  10. Surface plasmon enhanced cell microscopy with blocked random spatial activation

    Science.gov (United States)

    Son, Taehwang; Oh, Youngjin; Lee, Wonju; Yang, Heejin; Kim, Donghyun

    2016-03-01

    We present surface plasmon enhanced fluorescence microscopy with random spatial sampling using patterned block of silver nanoislands. Rigorous coupled wave analysis was performed to confirm near-field localization on nanoislands. Random nanoislands were fabricated in silver by temperature annealing. By analyzing random near-field distribution, average size of localized fields was found to be on the order of 135 nm. Randomly localized near-fields were used to spatially sample F-actin of J774 cells (mouse macrophage cell-line). Image deconvolution algorithm based on linear imaging theory was established for stochastic estimation of fluorescent molecular distribution. The alignment between near-field distribution and raw image was performed by the patterned block. The achieved resolution is dependent upon factors including the size of localized fields and estimated to be 100-150 nm.

  11. Donor-Acceptor Block Copolymers: Synthesis and Solar Cell Applications

    Directory of Open Access Journals (Sweden)

    Kazuhiro Nakabayashi

    2014-04-01

    Full Text Available Fullerene derivatives have been widely used for conventional acceptor materials in organic photovoltaics (OPVs because of their high electron mobility. However, there are also considerable drawbacks for use in OPVs, such as negligible light absorption in the visible-near-IR regions, less compatibility with donor polymeric materials and high cost for synthesis and purification. Therefore, the investigation of non-fullerene acceptor materials that can potentially replace fullerene derivatives in OPVs is increasingly necessary, which gives rise to the possibility of fabricating all-polymer (polymer/polymer solar cells that can deliver higher performance and that are potentially cheaper than fullerene-based OPVs. Recently, considerable attention has been paid to donor-acceptor (D-A block copolymers, because of their promising applications as fullerene alternative materials in all-polymer solar cells. However, the synthesis of D-A block copolymers is still a challenge, and therefore, the establishment of an efficient synthetic method is now essential. This review highlights the recent advances in D-A block copolymers synthesis and their applications in all-polymer solar cells.

  12. Curcumin blocks interleukin-1 signaling in chondrosarcoma cells.

    Directory of Open Access Journals (Sweden)

    Thomas Kalinski

    Full Text Available Interleukin (IL-1 signaling plays an important role in inflammatory processes, but also in malignant processes. The essential downstream event in IL-1 signaling is the activation of nuclear factor (NF-κB, which leads to the expression of several genes that are involved in cell proliferation, invasion, angiogenesis and metastasis, among them VEGF-A. As microenvironment-derived IL-1β is required for invasion and angiogenesis in malignant tumors, also in chondrosarcomas, we investigated IL-1β-induced signal transduction and VEGF-A expression in C3842 and SW1353 chondrosarcoma cells. We additionally performed in vitro angiogenesis assays and NF-κB-related gene expression analyses. Curcumin is a substance which inhibits IL-1 signaling very early by preventing the recruitment of IL-1 receptor associated kinase (IRAK to the IL-1 receptor. We demonstrate that IL-1 signaling and VEGF-A expression are blocked by Curcumin in chondrosarcoma cells. We further show that Curcumin blocks IL-1β-induced angiogenesis and NF-κB-related gene expression. We suppose that IL-1 blockade is an additional treatment option in chondrosarcoma, either by Curcumin, its derivatives or other IL-1 blocking agents.

  13. UV light blocks EGFR signalling in human cancer cell lines

    DEFF Research Database (Denmark)

    Olsen, BB; Neves-Petersen, M T; Klitgaard, S;

    2007-01-01

    antibodies. There was a threshold level, below which the receptor could not be blocked. In addition, illumination caused the cells to upregulate the cyclin-dependent kinase inhibitor p21WAF1, irrespective of the p53 status. Since the EGF receptor is often overexpressed in cancers and other proliferative skin......UV light excites aromatic residues, causing these to disrupt nearby disulphide bridges. The EGF receptor is rich in aromatic residues near the disulphide bridges. Herein we show that laser-pulsed UV illumination of two different skin-derived cancer cell lines i.e. Cal-39 and A431, which both...

  14. Selective Semiconductor Nanocluster Deposition on Eptaxially Patterned Semicrystalline Block Copolymer Film

    Science.gov (United States)

    Park, Cheolmin; Lee, Jinwook; Jensen, Klavs F.; Bawendi, Moungi G.; Thomas, Edwin L.

    2001-03-01

    Monodisperse ZnS encapsulated CdSe semiconductor nanoclusters are sequestered in between the crystalline polyethylene (PE) lamellae of poly (ethylene-b-ethylene-alt-propylene-b ethylene) semicrystalline triblock copolymer epitaxially crystallized on single crystal of anthracene (AN). Epitaxy between PE block and An created a cross oriented texture of the edge-on crystalline PE lamellae in the thin film. At the same time, the nanoclusters, initially dissolved in the mixture of block copolymer and AN, were rejected out of the crystalline lamellae during epitaxial crystallization and selectively deposited in the amorphous region of the block copolymer. Selective distribution of nanoclusters on the cross oriented pattern structure is clearly evidenced by selected area diffraction (SAD) and bright field transmission electron microscope (TEM).

  15. Block copolymers for alkaline fuel cell membrane materials

    Science.gov (United States)

    Li, Yifan

    Alkaline fuel cells (AFCs) using anion exchange membranes (AEMs) as electrolyte have recently received considerable attention. AFCs offer some advantages over proton exchange membrane fuel cells, including the potential of non-noble metal (e.g. nickel, silver) catalyst on the cathode, which can dramatically lower the fuel cell cost. The main drawback of traditional AFCs is the use of liquid electrolyte (e.g. aqueous potassium hydroxide), which can result in the formation of carbonate precipitates by reaction with carbon dioxide. AEMs with tethered cations can overcome the precipitates formed in traditional AFCs. Our current research focuses on developing different polymer systems (blend, block, grafted, and crosslinked polymers) in order to understand alkaline fuel cell membrane in many aspects and design optimized anion exchange membranes with better alkaline stability, mechanical integrity and ionic conductivity. A number of distinct materials have been produced and characterized. A polymer blend system comprised of poly(vinylbenzyl chloride)-b-polystyrene (PVBC-b-PS) diblock copolymer, prepared by nitroxide mediated polymerization (NMP), with poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) or brominated PPO was studied for conversion into a blend membrane for AEM. The formation of a miscible blend matrix improved mechanical properties while maintaining high ionic conductivity through formation of phase separated ionic domains. Using anionic polymerization, a polyethylene based block copolymer was designed where the polyethylene-based block copolymer formed bicontinuous morphological structures to enhance the hydroxide conductivity (up to 94 mS/cm at 80 °C) while excellent mechanical properties (strain up to 205%) of the polyethylene block copolymer membrane was observed. A polymer system was designed and characterized with monomethoxy polyethylene glycol (mPEG) as a hydrophilic polymer grafted through substitution of pendent benzyl chloride groups of a PVBC

  16. Renal dysfunction after total-body irradiation. Significance of selective renal shielding blocks

    Energy Technology Data Exchange (ETDEWEB)

    Igaki, Hiroshi [Tokyo Metropolitan Komagome Hospital (Japan). Dept. of Radiation Center; University of Tsukuba, Ibaraki (Japan). Proton Medical Research Center; University of Tokyo (Japan). Dept. of Radiology; Karasawa, Katsuyuki [Tokyo Metropolitan Komagome Hospital (Japan). Dept. of Radiation Center; Sakamaki, Hisashi [Tokyo Metropolitan Komagome Hospital (Japan). Dept. of Hematology; Saito, Hiroshi [Tokyo Metropolitan Komagome Hospital (Japan). Dept. of Nephrology; Nakagawa, Keiichi; Ohtomo, Kuni [University of Tokyo (Japan). Dept. of Radiology; Tanaka, Yoshiaki [Nihon University School of Medicine, Tokyo (Japan). Dept. of Radiology

    2005-11-01

    Purpose: A retrospective analysis was conducted on the outcome of total-body irradiation (TBI) followed by bone marrow transplantation (BMT) on leukemia patients. Also studied was the risk of renal dysfunction after TBI/BMT with or without the use of selective renal shielding blocks. Patients and Methods: The cases of 109 leukemia patients who received TBI as a component of the conditioning regimen for their BMT were reviewed. They received 12 Gy of TBI in six fractions over 3 consecutive days. Doses to eyes and lungs were reduced to 7 Gy and 8 Gy, respectively, but customized organ shielding blocks. After March 1999, renal shielding blocks were used to constrain the renal dose to 10 Gy. The patients were followed for a median period of 16.6 months (range: 0.3-180.1 months). Results: The 2-year and 5-year overall survival rates were 55.4% and 43.2%, respectively. Renal dysfunction-free rates were different between those with and without renal shielding blocks: 100% and 78.5%, respectively, at 2 years. Overall survivals were not significantly different among these patients: 60.4% and 52.9%, respectively, at 2 years in patients with and without renal shielding blocks (p=0.53). Conclusion: The use of selective renal shielding blocks provided evidence for reducing radiation-induced renal toxicities without decreasing the overall survival rate. (orig.)

  17. Saccharide blocking layers in solid state dye sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Handa, S.; Haque, S.A.; Durrant, J.R. [Department of Chemistry, Imperial College London, Exhibition Road, South Kensington, SW7 2AZ. London (United Kingdom)

    2007-10-15

    The adsorption of saccharides on dye sensitized, nanocrystalline metal oxide films is shown to improve the efficiency of solid state dye sensitized solar cells. The function of the saccharide treatment is evaluated by transient optical studies, and correlated with device photovoltaic performance. A range of saccharides, including cyclodextrins and their linear analogue amylose, are investigated. The saccharide blocking layer is shown to retard interfacial charge recombination losses, resulting in increased device open circuit voltage. Highest device performance is achieved with linear saccharide amylose, resulting in a 60 % improvement in device efficiency relative to the non-treated control, with a device open circuit voltage of 1 V. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

  18. EZH2 depletion blocks the proliferation of colon cancer cells.

    Directory of Open Access Journals (Sweden)

    Bettina Fussbroich

    Full Text Available The Enhancer of Zeste 2 (EZH2 protein has been reported to stimulate cell growth in some cancers and is therefore considered to represent an interesting new target for therapeutic intervention. Here, we investigated a possible role of EZH2 for the growth control of colon cancer cells. RNA interference (RNAi-mediated intracellular EZH2 depletion led to cell cycle arrest of colon carcinoma cells at the G1/S transition. This was associated with a reduction of cell numbers upon transient transfection of synthetic EZH2-targeting siRNAs and with inhibition of their colony formation capacity upon stable expression of vector-borne siRNAs. We furthermore tested whether EZH2 may repress the growth-inhibitory p27 gene, as reported for pancreatic cancer. However, expression analyses of colon cancer cell lines and colon cancer biopsies did not reveal a consistent correlation between EZH2 and p27 levels. Moreover, EZH2 depletion did not re-induce p27 expression in colon cancer cells, indicating that p27 repression by EZH2 may be cell- or tissue-specific. Whole genome transcriptome analyses identified cellular genes affected by EZH2 depletion in colon cancer cell lines. They included several cancer-associated genes linked to cellular proliferation or invasion, such as Dag1, MageD1, SDC1, Timp2, and Tob1. In conclusion, our results demonstrate that EZH2 depletion blocks the growth of colon cancer cells. These findings might provide benefits for the treatment of colon cancer.

  19. Nanomimics of host cell membranes block invasion and expose invasive malaria parasites.

    Science.gov (United States)

    Najer, Adrian; Wu, Dalin; Bieri, Andrej; Brand, Françoise; Palivan, Cornelia G; Beck, Hans-Peter; Meier, Wolfgang

    2014-12-23

    The fight against most infectious diseases, including malaria, is often hampered by the emergence of drug resistance and lack or limited efficacies of vaccines. Therefore, new drugs, vaccines, or other strategies to control these diseases are needed. Here, we present an innovative nanotechnological strategy in which the nanostructure itself represents the active substance with no necessity to release compounds to attain therapeutic effect and which might act in a drug- and vaccine-like dual function. Invasion of Plasmodium falciparum parasites into red blood cells was selected as a biological model for the initial validation of this approach. Stable nanomimics-polymersomes presenting receptors required for parasite attachment to host cells-were designed to efficiently interrupt the life cycle of the parasite by inhibiting invasion. A simple way to build nanomimics without postformation modifications was established. First, a block copolymer of the receptor with a hydrophobic polymer was synthesized and then mixed with a polymersome-forming block copolymer. The resulting nanomimics bound parasite-derived ligands involved in the initial attachment to host cells and they efficiently blocked reinvasion of malaria parasites after their egress from host cells in vitro. They exhibited efficacies of more than 2 orders of magnitude higher than the soluble form of the receptor, which can be explained by multivalent interactions of several receptors on one nanomimic with multiple ligands on the infective parasite. In the future, our strategy might offer interesting treatment options for severe malaria or a way to modulate the immune response. PMID:25435059

  20. Ras CAAX peptidomimetic FTI-277 selectively blocks oncogenic Ras signaling by inducing cytoplasmic accumulation of inactive Ras-Raf complexes.

    Science.gov (United States)

    Lerner, E C; Qian, Y; Blaskovich, M A; Fossum, R D; Vogt, A; Sun, J; Cox, A D; Der, C J; Hamilton, A D; Sebti, S M

    1995-11-10

    Ras-induced malignant transformation requires Ras farnesylation, a lipid posttranslational modification catalyzed by farnesyltransferase (FTase). Inhibitors of this enzyme have been shown to block Ras-dependent transformation, but the mechanism by which this occurs remains largely unknown. We have designed FTI-276, a peptide mimetic of the COOH-terminal Cys-Val-Ile-Met of K-Ras4B that inhibited potently FTase in vitro (IC50 = 500 pM) and was highly selective for FTase over geranylgeranyltransferase I (GGTase I) (IC50 = 50 nM). FTI-277, the methyl ester derivative of FTI-276, was extremely potent (IC50 = 100 nM) at inhibiting H-Ras, but not the geranylgeranylated Rap1A processing in whole cells. Treatment of H-Ras oncogene-transformed NIH 3T3 cells with FTI-277 blocked recruitment to the plasma membrane and subsequent activation of the serine/threonine kinase c-Raf-1 in cells transformed by farnesylated Ras (H-RasF), but not geranylgeranylated, Ras (H-RasGG). FTI-277 induced accumulation of cytoplasmic non-farnesylated H-Ras that was able to bind Raf and form cytoplasmic Ras/Raf complexes in which Raf kinase was not activated. Furthermore, FTI-277 blocked constitutive activation of mitogen-activated protein kinase (MAPK) in H-RasF, but not H-RasGG, or Raf-transformed cells. FTI-277 also inhibited oncogenic K-Ras4B processing and constitutive activation of MAPK, but the concentrations required were 100-fold higher than those needed for H-Ras inhibition. The results demonstrate that FTI-277 blocks Ras oncogenic signaling by accumulating inactive Ras/Raf complexes in the cytoplasm, hence preventing constitutive activation of the MAPK cascade.

  1. Enhancement of cell characteristics via baffle blocks in a proton exchange membrane fuel cell

    Indian Academy of Sciences (India)

    Atilla Biyikoglu; Hülya Oztoprak

    2012-04-01

    In this study, the effects of baffle blocks located in the flow channel on fuel cell characteristics were investigated. The higher current densities were obtained from the cells with blockage than without blockage. It was observed that the gap between the tip of the baffle block and the channel wall had a significant effect on the current density produced and on the convergence of solutions. The number and the size of blocks that are providing the highest current density from the cell were determined. No significant effects were observed in the polarization curves for cells with more than four blocks and gap ratio of 0.3. A parametric study was conducted to investigate the effect of the relative humidity and velocity of inlet gases on cells with four blocks and gap ratio of 0.3. It was concluded that the current density is strongly dependent on the relative humidity for low inlet velocities and on the other hand, on the inlet velocity for low relative humidities.

  2. An Optimization Approach for Selecting Blocks of Embedding Process in Robust Watermarking System

    Directory of Open Access Journals (Sweden)

    Ababneh M.F. Mohammad

    2006-01-01

    Full Text Available This study, discusses several kinds of attacks that may meet the watermarked image such as JPEG compression, Gaussian noise and median filter. The study introduces an approach capable of selecting the optimal blocks in cover image to be used in embedding process. Also, in this study, we propose a technique in robust digital watermarking system looking for finding a relation between the contrast of cover image and robustness to increase the resistance of previous attacks.

  3. Phase diagram of selectively cross-linked block copolymers shows chemically microstructured gel

    OpenAIRE

    von der Heydt, Alice; Zippelius, Annette

    2014-01-01

    We study analytically the intricate phase behavior of cross-linked $AB$ diblock copolymer melts, which can undergo two main phase transitions due to quenched random constraints: Gelation, i.e., spatially random localization of polymers forming a system-spanning cluster, is driven by increasing the number parameter $\\mu$ of irreversible, type-selective cross-links between random pairs of $A$ blocks. Self-assembly into a periodic pattern of $A$/$B$-rich microdomains (microphase separation) is c...

  4. An alternative blocking layer for titanium dioxide (TiO 2) solar cell applications

    OpenAIRE

    Memesa, M.

    2008-01-01

    In hybrid organic solar cells a blocking layer between transparent electrode and nanocrystalline titania particles is essential to prevent short-circuiting and current loss through recombination at the electrode interface. Here the preparation of a uniform hybrid blocking layer which is composed of conducting titania nanoparticles embedded in an insulating polymer derived ceramic is presented. This blocking layer is prepared by sol-gel chemistry where an amphiphilic block copolymer is use...

  5. Enhancement of photoconversion efficiency in dye-sensitized solar cells exploiting pulsed laser deposited niobium pentoxide blocking layers

    International Nuclear Information System (INIS)

    Among all the photovoltaic technologies developed so far, dye-sensitized solar cells are considered as a promising alternative to the expensive and environmentally unfriendly crystalline silicon-based solar cells. One of the possible strategies employed to increase their photovoltaic efficiency is to reduce the charge recombination at the cell conductive substrate through the use of a compact blocking layer. In this paper, we report on the fabrication and characterization of dye-sensitized solar cells employing niobium pentoxide (Nb2O5) thin film blocking layer deposited through the pulsed laser deposition technique on conductive substrates. The careful selection of the optimal film thickness led to a 30% enhancement of the photoconversion efficiency with respect to reference cells fabricated without blocking layer. Open circuit voltage decay and electrochemical impedance spectroscopy techniques proved that the effective suppression of the charge recombination occurring at the substrate/electrolyte interface represents the main reason for the improvement of the photovoltaic efficiency. - Highlights: • Niobium pentoxide thin films were fabricated through pulsed laser deposition. • The deposited films were employed as recombination blocking layer in DSCs. • The selection of the optimal film thickness led to the enhancement of the efficiency

  6. Enhancement of photoconversion efficiency in dye-sensitized solar cells exploiting pulsed laser deposited niobium pentoxide blocking layers

    Energy Technology Data Exchange (ETDEWEB)

    Sacco, Adriano, E-mail: adriano.sacco@iit.it [Center for Space Human Robotics@PoliTo, Istituto Italiano di Tecnologia, Corso Trento 21, 10129 Torino (Italy); Di Bella, Maurizio Salvatore [Department of Energy, Information Engineering and Mathematical Models (DEIM), Thin Films Laboratory, Università di Palermo, Viale delle Scienze, Building 9, 90128 Palermo (Italy); Gerosa, Matteo [Center for Space Human Robotics@PoliTo, Istituto Italiano di Tecnologia, Corso Trento 21, 10129 Torino (Italy); Applied Science and Technology Department (DISAT), Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Chiodoni, Angelica; Bianco, Stefano [Center for Space Human Robotics@PoliTo, Istituto Italiano di Tecnologia, Corso Trento 21, 10129 Torino (Italy); Mosca, Mauro; Macaluso, Roberto; Calì, Claudio [Department of Energy, Information Engineering and Mathematical Models (DEIM), Thin Films Laboratory, Università di Palermo, Viale delle Scienze, Building 9, 90128 Palermo (Italy); Pirri, Candido Fabrizio [Center for Space Human Robotics@PoliTo, Istituto Italiano di Tecnologia, Corso Trento 21, 10129 Torino (Italy); Applied Science and Technology Department (DISAT), Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy)

    2015-01-01

    Among all the photovoltaic technologies developed so far, dye-sensitized solar cells are considered as a promising alternative to the expensive and environmentally unfriendly crystalline silicon-based solar cells. One of the possible strategies employed to increase their photovoltaic efficiency is to reduce the charge recombination at the cell conductive substrate through the use of a compact blocking layer. In this paper, we report on the fabrication and characterization of dye-sensitized solar cells employing niobium pentoxide (Nb{sub 2}O{sub 5}) thin film blocking layer deposited through the pulsed laser deposition technique on conductive substrates. The careful selection of the optimal film thickness led to a 30% enhancement of the photoconversion efficiency with respect to reference cells fabricated without blocking layer. Open circuit voltage decay and electrochemical impedance spectroscopy techniques proved that the effective suppression of the charge recombination occurring at the substrate/electrolyte interface represents the main reason for the improvement of the photovoltaic efficiency. - Highlights: • Niobium pentoxide thin films were fabricated through pulsed laser deposition. • The deposited films were employed as recombination blocking layer in DSCs. • The selection of the optimal film thickness led to the enhancement of the efficiency.

  7. OPTIMAL ANTENNA SUBSET SELECTION AND BLIND DETECTION APPROACH APPLIED TO ORTHOGONAL SPACE-TIME BLOCK CODING

    Institute of Scientific and Technical Information of China (English)

    Xu Hongji; Liu Ju; Gu Bo

    2007-01-01

    An approach combining optimal antenna subset selection with blind detection scheme for Orthogonal Space-Time Block Coding (OSTBC) is proposed in this paper. The optimal antenna subset selection is taken into account at transmitter and/or receiver sides, which chooses the optimal antennas to increase the diversity order of OSTBC and improve further its performance. In order to enhance the robustness of the detection used in the conventional OSTBC scheme, a blind detection scheme based on Independent Component Analysis (ICA) is exploited which can directly extract transmitted signals without channel estimation. Performance analysis shows that the proposed approach can achieve the full diversity and the flexibility of system design by using the antenna selection and the ICA based blind detection schemes.

  8. Selective source blocking for Gamma Knife radiosurgery of trigeminal neuralgia based on analytical dose modelling

    Energy Technology Data Exchange (ETDEWEB)

    Li Kaile; Ma Lijun [Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD 21210 (United States)

    2004-08-07

    We have developed an automatic critical region shielding (ACRS) algorithm for Gamma Knife radiosurgery of trigeminal neuralgia. The algorithm selectively blocks 201 Gamma Knife sources to minimize the dose to the brainstem while irradiating the root entry area of the trigeminal nerve with 70-90 Gy. An independent dose model was developed to implement the algorithm. The accuracy of the dose model was tested and validated via comparison with the Leksell GammaPlan (LGP) calculations. Agreements of 3% or 3 mm in isodose distributions were found for both single-shot and multiple-shot treatment plans. After the optimized blocking patterns are obtained via the independent dose model, they are imported into the LGP for final dose calculations and treatment planning analyses. We found that the use of a moderate number of source plugs (30-50 plugs) significantly lowered ({approx}40%) the dose to the brainstem for trigeminal neuralgia treatments. Considering the small effort involved in using these plugs, we recommend source blocking for all trigeminal neuralgia treatments with Gamma Knife radiosurgery.

  9. Selective source blocking for Gamma Knife radiosurgery of trigeminal neuralgia based on analytical dose modelling

    International Nuclear Information System (INIS)

    We have developed an automatic critical region shielding (ACRS) algorithm for Gamma Knife radiosurgery of trigeminal neuralgia. The algorithm selectively blocks 201 Gamma Knife sources to minimize the dose to the brainstem while irradiating the root entry area of the trigeminal nerve with 70-90 Gy. An independent dose model was developed to implement the algorithm. The accuracy of the dose model was tested and validated via comparison with the Leksell GammaPlan (LGP) calculations. Agreements of 3% or 3 mm in isodose distributions were found for both single-shot and multiple-shot treatment plans. After the optimized blocking patterns are obtained via the independent dose model, they are imported into the LGP for final dose calculations and treatment planning analyses. We found that the use of a moderate number of source plugs (30-50 plugs) significantly lowered (∼40%) the dose to the brainstem for trigeminal neuralgia treatments. Considering the small effort involved in using these plugs, we recommend source blocking for all trigeminal neuralgia treatments with Gamma Knife radiosurgery

  10. Selective source blocking for Gamma Knife radiosurgery of trigeminal neuralgia based on analytical dose modelling

    Science.gov (United States)

    Li, Kaile; Ma, Lijun

    2004-08-01

    We have developed an automatic critical region shielding (ACRS) algorithm for Gamma Knife radiosurgery of trigeminal neuralgia. The algorithm selectively blocks 201 Gamma Knife sources to minimize the dose to the brainstem while irradiating the root entry area of the trigeminal nerve with 70-90 Gy. An independent dose model was developed to implement the algorithm. The accuracy of the dose model was tested and validated via comparison with the Leksell GammaPlan (LGP) calculations. Agreements of 3% or 3 mm in isodose distributions were found for both single-shot and multiple-shot treatment plans. After the optimized blocking patterns are obtained via the independent dose model, they are imported into the LGP for final dose calculations and treatment planning analyses. We found that the use of a moderate number of source plugs (30-50 plugs) significantly lowered (~40%) the dose to the brainstem for trigeminal neuralgia treatments. Considering the small effort involved in using these plugs, we recommend source blocking for all trigeminal neuralgia treatments with Gamma Knife radiosurgery.

  11. The Role of Selective Nerve Root Block in the Treatment of Lumbar Radicular Leg Pain.

    Science.gov (United States)

    Jonayed, S A; Kamruzzaman, M; Saha, M K; Alam, S; Akter, S

    2016-01-01

    The objective of this retrospective study was to investigate the clinical effectiveness of nerve root blocks (i.e., periradicular injection of Lidocaine and triamcinolone) for lumbar monoradiculopathy in patients with a mild neurological deficit in National Institute of Traumatology & Orthopaedic Rehabilitation (NITOR), Dhaka, Bangladesh from March 2014 to December 2014. We Included 24 patients (32-74 years) with a minor sensory/motor deficit and an unequivocal MRI finding (18 disc herniations, 6 foraminal stenosis) treated with a selective nerve root block. Based on the clinical and imaging findings, surgery (decompression of the nerve root) was justifiable in all cases. Seventeen patients (87%) had rapid (1-4 days) and substantial regression of pain, four required a repeat injection. Sixty percent (60%) of the patients with disc herniation or foraminal stenosis had permanent resolution of pain, so that an operation was avoided over an average of 6 months (2-9 months) follow-up. Nerve root blocks are very effective in the non-operative treatment of minor monoradiculopathy and should be recommended as the initial treatment of choice for this condition. PMID:26931264

  12. Fuzzy Approach for Selecting Optimal COTS Based Software Products Under Consensus Recovery Block Scheme

    Directory of Open Access Journals (Sweden)

    P. C. Jha

    2011-01-01

    Full Text Available The cost associated with development of a large and complex software system is formidable. In today's customer driven market, improvement of quality aspects in terms of reliability of the product is also gaining increased importance. But the resources are limited and the manager has to maneuver within a tight schedule. In order to meet these challenges, many organizations are making use of Commercial Off-The-Shelf (COTS software. This paper develops a fuzzy multi objective optimization model approach for selecting the optimal COTS software product among alternatives for each module in the development of modular software system. The problem is formulated for consensus recovery block fault tolerant scheme. In today’s ever changing environment, it is arduous to estimate the precise cost and reliability of software. Therefore, we develop a fuzzy multi objective optimization models for selecting optimal COTS software products. Numerical illustrations are provided to demonstrate the models developed.

  13. Conservation analysis of dengue virust-cell epitope-based vaccine candidates using peptide block entropy

    DEFF Research Database (Denmark)

    Olsen, Lars Rønn; Zhang, Guang Lan; Keskin, Derin B.;

    2011-01-01

    Broad coverage of the pathogen population is particularly important when designing CD8+ T-cell epitope vaccines against viral pathogens. Traditional approaches are based on combinations of highly conserved T-cell epitopes. Peptide block entropy analysis is a novel approach for assembling sets....... In contrast, the benchmark study by Khan et al. (2008) resulted in 165 conserved 9-mer peptides. Many of the conserved blocks are located consecutively in the proteins. Connecting these blocks resulted in 78 conserved regions. Of the 1551 blocks of 9-mer peptides 110 comprised predicted HLA binder sets...

  14. Manipulation of a quasi-natural cell block for high-efficiency transplantation of adherent somatic cells

    OpenAIRE

    Chung, H.J.; Hassan, M. M.; Park, J O; Kim, H. J.; S.T. Hong

    2015-01-01

    Recent advances have raised hope that transplantation of adherent somatic cells could provide dramatic new therapies for various diseases. However, current methods for transplanting adherent somatic cells are not efficient enough for therapeutic applications. Here, we report the development of a novel method to generate quasi-natural cell blocks for high-efficiency transplantation of adherent somatic cells. The blocks were created by providing a unique environment in which cultured cells gene...

  15. Sodium selectivity of Reissner's membrane epithelial cells

    Directory of Open Access Journals (Sweden)

    Kim Kyunghee X

    2011-02-01

    Full Text Available Abstract Background Sodium absorption by Reissner's membrane is thought to contribute to the homeostasis of the volume of cochlear endolymph. It was previously shown that the absorptive transepithelial current was blocked by amiloride and benzamil. The most commonly-observed target of these drugs is the epithelial sodium channel (ENaC, which is composed of the three subunits α-,β- and γ-ENaC. However, other less-selective cation channels have also been observed to be sensitive to benzamil and amiloride. The aim of this study was to determine whether Reissner's membrane epithelial cells could support parasensory K+ absorption via amiloride- and benzamil-sensitive electrogenic pathways. Results We determined the molecular and functional expression of candidate cation channels with gene array (GEO GSE6196, RT-PCR, and whole-cell patch clamp. Transcript expression analysis of Reissner's membrane detected no amiloride-sensitive acid-sensing ion channels (ASIC1a, ASIC2a, ASIC2b nor amiloride-sensitive cyclic-nucleotide gated channels (CNGA1, CNGA2, CNGA4, CNGB3. By contrast, α-,β- and γ-ENaC were all previously reported as present in Reissner's membrane. The selectivity of the benzamil-sensitive cation currents was observed in whole-cell patch clamp recordings under Cl--free conditions where cations were the only permeant species. The currents were carried by Na+ but not K+, and the permeability of Li+ was greater than that of Na+ in Reissner's membrane. Complete replacement of bath Na+ with the inpermeable cation NMDG+ led to the same inward current as with benzamil in a Na+ bath. Conclusions These results are consistent with the amiloride/benzamil-sensitive absorptive flux of Reissner's membrane mediated by a highly Na+-selective channel that has several key characteristics in common with αβγ-ENaC. The amiloride-sensitive pathway therefore absorbs only Na+ in this epithelium and does not provide a parasensory K+ efflux route from scala

  16. Kalkitoxin Inhibits Angiogenesis, Disrupts Cellular Hypoxic Signaling, and Blocks Mitochondrial Electron Transport in Tumor Cells

    Directory of Open Access Journals (Sweden)

    J. Brian Morgan

    2015-03-01

    Full Text Available The biologically active lipopeptide kalkitoxin was previously isolated from the marine cyanobacterium Moorea producens (Lyngbya majuscula. Kalkitoxin exhibited N-methyl-d-aspartate (NMDA-mediated neurotoxicity and acted as an inhibitory ligand for voltage-sensitive sodium channels in cultured rat cerebellar granule neurons. Subsequent studies revealed that kalkitoxin generated a delayed form of colon tumor cell cytotoxicity in 7-day clonogenic cell survival assays. Cell line- and exposure time-dependent cytostatic/cytotoxic effects were previously observed with mitochondria-targeted inhibitors of hypoxia-inducible factor-1 (HIF-1. The transcription factor HIF-1 functions as a key regulator of oxygen homeostasis. Therefore, we investigated the ability of kalkitoxin to inhibit hypoxic signaling in human tumor cell lines. Kalkitoxin potently and selectively inhibited hypoxia-induced activation of HIF-1 in T47D breast tumor cells (IC50 5.6 nM. Mechanistic studies revealed that kalkitoxin inhibits HIF-1 activation by suppressing mitochondrial oxygen consumption at electron transport chain (ETC complex I (NADH-ubiquinone oxidoreductase. Further studies indicate that kalkitoxin targets tumor angiogenesis by blocking the induction of angiogenic factors (i.e., VEGF in tumor cells.

  17. Synthesis of Inorganic Nanocomposites by Selective Introduction of Metal Complexes into a Self-Assembled Block Copolymer Template

    Directory of Open Access Journals (Sweden)

    Hiroaki Wakayama

    2015-01-01

    Full Text Available Inorganic nanocomposites have characteristic structures that feature expanded interfaces, quantum effects, and resistance to crack propagation. These structures are promising for the improvement of many materials including thermoelectric materials, photocatalysts, and structural materials. Precise control of the inorganic nanocomposites’ morphology, size, and chemical composition is very important for these applications. Here, we present a novel fabrication method to control the structures of inorganic nanocomposites by means of a self-assembled block copolymer template. Different metal complexes were selectively introduced into specific polymer blocks of the block copolymer, and subsequent removal of the block copolymer template by oxygen plasma treatment produced hexagonally packed porous structures. In contrast, calcination removal of the block copolymer template yielded nanocomposites consisting of metallic spheres in a matrix of a metal oxide. These results demonstrate that different nanostructures can be created by selective use of processes to remove the block copolymer templates. The simple process of first mixing block copolymers and magnetic nanomaterial precursors and then subsequently removing the block copolymer template enables structural control of magnetic nanomaterials, which will facilitate their applicability in patterned media, including next-generation perpendicular magnetic recording media.

  18. Formation of nanoscale networks: selectively swelling amphiphilic block copolymers with CO2-expanded liquids

    Science.gov (United States)

    Gong, Jianliang; Zhang, Aijuan; Bai, Hua; Zhang, Qingkun; Du, Can; Li, Lei; Hong, Yanzhen; Li, Jun

    2013-01-01

    Polymeric films with nanoscale networks were prepared by selectively swelling an amphiphilic diblock copolymer, polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP), with the CO2-expanded liquid (CXL), CO2-methanol. The phase behavior of the CO2-methanol system was investigated by both theoretical calculation and experiments, revealing that methanol can be expanded by CO2, forming homogeneous CXL under the experimental conditions. When treated with the CO2-methanol system, the spin cast compact PS-b-P4VP film was transformed into a network with interconnected pores, in a pressure range of 12-20 MPa and a temperature range of 45-60 °C. The formation mechanism of the network, involving plasticization of PS and selective swelling of P4VP, was proposed. Because the diblock copolymer diffusion process is controlled by the activated hopping of individual block copolymer chains with the thermodynamic barrier for moving PVP segments from one to another, the formation of the network structures is achieved in a short time scale and shows ``thermodynamically restricted'' character. Furthermore, the resulting polymer networks were employed as templates, for the preparation of polypyrrole networks, by an electrochemical polymerization process. The prepared porous polypyrrole film was used to fabricate a chemoresistor-type gas sensor which showed high sensitivity towards ammonia.Polymeric films with nanoscale networks were prepared by selectively swelling an amphiphilic diblock copolymer, polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP), with the CO2-expanded liquid (CXL), CO2-methanol. The phase behavior of the CO2-methanol system was investigated by both theoretical calculation and experiments, revealing that methanol can be expanded by CO2, forming homogeneous CXL under the experimental conditions. When treated with the CO2-methanol system, the spin cast compact PS-b-P4VP film was transformed into a network with interconnected pores, in a pressure range of 12-20 MPa and a

  19. Selective Inhibition and Naming Performance in Semantic Blocking, Picture-Word Interference, and Color-Word Stroop Tasks

    Science.gov (United States)

    Shao, Zeshu; Roelofs, Ardi; Martin, Randi C.; Meyer, Antje S.

    2015-01-01

    In 2 studies, we examined whether explicit distractors are necessary and sufficient to evoke selective inhibition in 3 naming tasks: the semantic blocking, picture-word interference, and color-word Stroop task. Delta plots were used to quantify the size of the interference effects as a function of reaction time (RT). Selective inhibition was…

  20. Nondestructive Creation of Ordered Nanopores by Selective Swelling of Block Copolymers: Toward Homoporous Membranes.

    Science.gov (United States)

    Wang, Yong

    2016-07-19

    Pores regulate the entry and exit of substances based on the differences in physical sizes or chemical affinities. Pore uniformity, ordering, and the homogeneity of the surface chemistry of the pore walls are vital for maximizing the performance of a porous material because any scattering in these parameters weakens the capability of pores to discriminate foreign substances. Most strategies for the creation of homogeneous pores are destructive, and sacrificial components in the precursor materials must be selectively removed to generate porosities. The incorporation and subsequent removal of the sacrificial components frequently make the pore-making process complicated and inefficient and impose greater uncertainty in the control of the pore homogeneity. Block copolymers (BCPs) have been demonstrated to be promising precursors in the fabrication of highly ordered nanoporous structures. Unfortunately, BCP-derived porosities are also predominantly dependent on destructive pore-making processes (e.g., etching or extraction). To address this problem, we have developed a swelling-based nondestructive strategy. In this swelling process, one simply needs to immerse BCP materials in a solvent selective for the minority blocks for hours. After removing the BCPs from the solvent followed by air drying, pores are generated throughout the BCP materials in the positions where the minority blocks initially dwell. This Account discusses our recent discoveries, new insights, and emerging applications of this burgeoning pore-making method with a focus on the development of ordered porosities in bulk BCP materials. The initial morphology and orientation of the minority phases in BCPs determine the pore orientation and geometry in the produced porous materials. For nonaligned BCPs, three-dimensionally interconnected pores with sizes scattering in the 10-50 nm range are produced after swelling. There is a morphology evolution of BCP materials from the initial nonporous structure to

  1. Inhibition of host cell translation elongation by Legionella pneumophila blocks the host cell unfolded protein response

    Science.gov (United States)

    Hempstead, Andrew D.; Isberg, Ralph R.

    2015-01-01

    Cells of the innate immune system recognize bacterial pathogens by detecting common microbial patterns as well as pathogen-specific activities. One system that responds to these stimuli is the IRE1 branch of the unfolded protein response (UPR), a sensor of endoplasmic reticulum (ER) stress. Activation of IRE1, in the context of Toll-like receptor (TLR) signaling, induces strong proinflammatory cytokine induction. We show here that Legionella pneumophila, an intravacuolar pathogen that replicates in an ER-associated compartment, blocks activation of the IRE1 pathway despite presenting pathogen products that stimulate this response. L. pneumophila TLR ligands induced the splicing of mRNA encoding XBP1s, the main target of IRE1 activity. L. pneumophila was able to inhibit both chemical and bacterial induction of XBP1 splicing via bacterial translocated proteins that interfere with host protein translation. A strain lacking five translocated translation elongation inhibitors was unable to block XBP1 splicing, but this could be rescued by expression of a single such inhibitor, consistent with limitation of the response by translation elongation inhibitors. Chemical inhibition of translation elongation blocked pattern recognition receptor-mediated XBP1 splicing, mimicking the effects of the bacterial translation inhibitors. In contrast, host cell-promoted inhibition of translation initiation in response to the pathogen was ineffective in blocking XBP1 splicing, demonstrating the need for the elongation inhibitors for protection from the UPR. The inhibition of host translation elongation may be a common strategy used by pathogens to limit the innate immune response by interfering with signaling via the UPR. PMID:26598709

  2. Phase diagram of selectively cross-linked block copolymers shows chemically microstructured gel

    Science.gov (United States)

    von der Heydt, Alice; Zippelius, Annette

    2015-02-01

    We study analytically the intricate phase behavior of cross-linked AB diblock copolymer melts, which can undergo two main phase transitions due to quenched random constraints. Gelation, i.e., spatially random localisation of polymers forming a system-spanning cluster, is driven by increasing the number parameter μ of irreversible, type-selective cross-links between random pairs of A blocks. Self-assembly into a periodic pattern of A/B-rich microdomains (microphase separation) is controlled by the AB incompatibility χ inversely proportional to temperature. Our model aims to capture the system's essential microscopic features, including an ensemble of random networks that reflects spatial correlations at the instant of cross-linking. We identify suitable order parameters and derive a free-energy functional in the spirit of Landau theory that allows us to trace a phase diagram in the plane of μ and χ. Selective cross-links promote microphase separation at higher critical temperatures than in uncross-linked diblock copolymer melts. Microphase separation in the liquid state facilitates gelation, giving rise to a novel gel state whose chemical composition density mirrors the periodic AB pattern.

  3. Phase diagram of selectively cross-linked block copolymers shows chemically microstructured gel.

    Science.gov (United States)

    von der Heydt, Alice; Zippelius, Annette

    2015-02-01

    We study analytically the intricate phase behavior of cross-linked AB diblock copolymer melts, which can undergo two main phase transitions due to quenched random constraints. Gelation, i.e., spatially random localisation of polymers forming a system-spanning cluster, is driven by increasing the number parameter μ of irreversible, type-selective cross-links between random pairs of A blocks. Self-assembly into a periodic pattern of A/B-rich microdomains (microphase separation) is controlled by the AB incompatibility χ inversely proportional to temperature. Our model aims to capture the system's essential microscopic features, including an ensemble of random networks that reflects spatial correlations at the instant of cross-linking. We identify suitable order parameters and derive a free-energy functional in the spirit of Landau theory that allows us to trace a phase diagram in the plane of μ and χ. Selective cross-links promote microphase separation at higher critical temperatures than in uncross-linked diblock copolymer melts. Microphase separation in the liquid state facilitates gelation, giving rise to a novel gel state whose chemical composition density mirrors the periodic AB pattern. PMID:25662662

  4. Clustered Intracellular Salmonella enterica Serovar Typhimurium Blocks Host Cell Cytokinesis.

    Science.gov (United States)

    Santos, António J M; Durkin, Charlotte H; Helaine, Sophie; Boucrot, Emmanuel; Holden, David W

    2016-07-01

    Several bacterial pathogens and viruses interfere with the cell cycle of their host cells to enhance virulence. This is especially apparent in bacteria that colonize the gut epithelium, where inhibition of the cell cycle of infected cells enhances the intestinal colonization. We found that intracellular Salmonella enterica serovar Typhimurium induced the binucleation of a large proportion of epithelial cells by 14 h postinvasion and that the effect was dependent on an intact Salmonella pathogenicity island 2 (SPI-2) type 3 secretion system. The SPI-2 effectors SseF and SseG were required to induce binucleation. SseF and SseG are known to maintain microcolonies of Salmonella-containing vacuoles close to the microtubule organizing center of infected epithelial cells. During host cell division, these clustered microcolonies prevented the correct localization of members of the chromosomal passenger complex and mitotic kinesin-like protein 1 and consequently prevented cytokinesis. Tetraploidy, arising from a cytokinesis defect, is known to have a deleterious effect on subsequent cell divisions, resulting in either chromosomal instabilities or cell cycle arrest. In infected mice, proliferation of small intestinal epithelial cells was compromised in an SseF/SseG-dependent manner, suggesting that cytokinesis failure caused by S Typhimurium delays epithelial cell turnover in the intestine.

  5. Delay of ZGA initiation occurred in 2-cell blocked mouse embryos

    Institute of Scientific and Technical Information of China (English)

    JIA JING QIU; WU WEN ZHANG; ZHI LI WU; YI HONG WANG; MIN QIAN; YI PING LI

    2003-01-01

    One-cell mouse embryos from KM strain and B6C3F1 strain were cultured in M16 medium, in which2-cell block generally occurs. Embryos of KM strain exhibited 2-cell block, whereas B6C3F1 embryos,which are regarded as a nonblocking strain, proceeded to the 4-cell stage in our culture condition. It is oftenassumed that the block of early development is due to the failure of zygotic gene activation (ZGA) in culturedembryos. In this study we examined protein synthesis patterns by two-dimensional gel electrophoresis of[35S] methionine radiolabeled 2-cell embryos. Embryos from the blocking strain and the nonblocking strainwere compared in their development both in vitro and in vivo. The detection of TRC expression, a markerof ZGA, at 42 h post hCG in KM embryos developed in vitro suggested that ZGA was also initiated even inthe 2-cell arrested embryos. Nevertheless, a significant delay of ZGA was observed in KM strain as comparedwith normally developed B6C3F1 embryos. At the very beginning of major ZGA as early as 36 h post hCG,TRC has already been expressed in B6C3F1 embryos developed in vitro and KM embryos developed in vivo.But for 2-cell blocked KM embryos, TRC was still not detectable even at 38 h post hCG. These evidencessuggest that 2-cell-blocked embryos do initiate ZGA, and that 2-cell block phenomenon is due not to thedisability in initiating ZGA, but to a delay of ZGA.

  6. 7-Chloroarctinone-b as a new selective PPARγ antagonist potently blocks adipocyte differentiation

    Institute of Scientific and Technical Information of China (English)

    Yong-tao LI; Li LI; Jing CHEN; Tian-cen HU; Jin HUANG; Yue-wei GUO; Hua-liang JIANG; Xu SHEN

    2009-01-01

    Aim: Peroxisome proliferator-activated receptor gamma (PPARy) is a therapeutic target for obesity, cancer and diabetes mellitus. In order to develop potent lead compounds for obesity treatment, we screened a natural product library for novel PPARy antagonists with inhibitory effects on adipocyte differentiation. Methods: Surface plasmon resonance (SPR) technology and cell-based transactivation assay were used to screen for PPARy antago-nists. To investigate the antagonistic mechanism of the active compound, we measured its effect on PPARy/RXRα heterodimerization and PPARy co-activator recruitment using yeast two-hybrid assay, Gal4/UAS cell-based assay and SPR based assay. The 3T3-L1 cell differentiation assay was used to evaluate the effect of the active compound on adipocyte differentiation. Results: A new thiophene-acetylene type of natural product, 7-chloroarctinone-b (CAB), isolated from the roots of Rhaponticum uniflo-rum, was discovered as a novel PPARγ antagonist capable of inhibiting rosiglitazone-induced PPARγ transcriptional activity. SPR analy-sis suggested that CAB bound tightly to PPARγ and considerably antagonized the potent PPARy agonist rosigtitazone-stimulated PPARγ-LBD/RXRα-LBD binding. Gal4/UAS and yeast two-hybrid assays were used to evaluate the antagonistic activity of CAB on rosiglitazone-induced recruitment of the coactivator for PPARy. CAB could efficiently antagonize both hormone and rosiglitazone-induced adipocyte differentiation in cell culture. Conclusion: CAB shows antagonistic activity to PPARγ and can block the adipocyte differentiation, indicating it may be of potential use as a lead therapeutic compound for obesity.

  7. Hair cell recovery in mitotically blocked cultures of the bullfrog saccule

    Science.gov (United States)

    Baird, R. A.; Burton, M. D.; Fashena, D. S.; Naeger, R. A.

    2000-01-01

    Hair cells in many nonmammalian vertebrates are regenerated by the mitotic division of supporting cell progenitors and the differentiation of the resulting progeny into new hair cells and supporting cells. Recent studies have shown that nonmitotic hair cell recovery after aminoglycoside-induced damage can also occur in the vestibular organs. Using hair cell and supporting cell immunocytochemical markers, we have used confocal and electron microscopy to examine the fate of damaged hair cells and the origin of immature hair cells after gentamicin treatment in mitotically blocked cultures of the bullfrog saccule. Extruding and fragmenting hair cells, which undergo apoptotic cell death, are replaced by scar formations. After losing their bundles, sublethally damaged hair cells remain in the sensory epithelium for prolonged periods, acquiring supporting cell-like morphology and immunoreactivity. These modes of damage appear to be mutually exclusive, implying that sublethally damaged hair cells repair their bundles. Transitional cells, coexpressing hair cell and supporting cell markers, are seen near scar formations created by the expansion of neighboring supporting cells. Most of these cells have morphology and immunoreactivity similar to that of sublethally damaged hair cells. Ultrastructural analysis also reveals that most immature hair cells had autophagic vacuoles, implying that they originated from damaged hair cells rather than supporting cells. Some transitional cells are supporting cells participating in scar formations. Supporting cells also decrease in number during hair cell recovery, supporting the conclusion that some supporting cells undergo phenotypic conversion into hair cells without an intervening mitotic event.

  8. Lexical selection in the semantically blocked cyclic naming task: the role of cognitive control and learning.

    Science.gov (United States)

    Crowther, Jason E; Martin, Randi C

    2014-01-01

    Studies of semantic interference in language production have provided evidence for a role of cognitive control mechanisms in regulating the activation of semantic competitors during naming. The present study investigated the relationship between individual differences in cognitive control abilities, for both younger and older adults, and the degree of semantic interference in a blocked cyclic naming task. We predicted that individuals with lower working memory capacity (as measured by word span), lesser ability to inhibit distracting responses (as measured by Stroop interference), and a lesser ability to resolve proactive interference (as measured by a recent negatives task) would show a greater increase in semantic interference in naming, with effects being larger for older adults. Instead, measures of cognitive control were found to relate to specific indices of semantic interference in the naming task, rather than overall degree of semantic interference, and few interactions with age were found, with younger and older adults performing similarly. The increase in naming latencies across naming trials within a cycle were negatively correlated with word span for both related and unrelated conditions, suggesting a strategy of narrowing response alternatives based upon memory for the set of item names. Evidence for a role of inhibition in response selection was obtained, as Stroop interference correlated positively with the change in naming latencies across cycles for the related, but not unrelated, condition. In contrast, recent negatives interference correlated negatively with the change in naming latencies across unrelated cycles, suggesting that individual differences in this tap the degree of strengthening of links in a lexical network based upon prior exposure. Results are discussed in terms of current models of lexical selection and consequences for word retrieval in more naturalistic production. PMID:24478675

  9. Lexical selection in the semantically blocked cyclic naming task: The role of cognitive control and learning

    Directory of Open Access Journals (Sweden)

    Jason E. Crowther

    2014-01-01

    Full Text Available Studies of semantic interference in language production have provided evidence for a role of cognitive control mechanisms in regulating the activation of semantic competitors during naming. The present study investigated the relationship between individual differences in cognitive control abilities, for both younger and older adults, and the degree of semantic interference in a blocked cyclic naming task. We predicted that individuals with lower working memory capacity (as measured by word span, lesser ability to inhibit distracting responses (as measured by Stroop interference, and a lesser ability to resolve proactive interference (as measured by a recent negatives task would show a greater increase in semantic interference in naming, with effects being larger for older adults. Instead, measures of cognitive control were found to relate to specific indices of semantic interference in the naming task, rather than overall degree of semantic interference, and few interactions with age were found, with younger and older adults performing similarly. The increase in naming latencies across naming trials within a cycle were negatively correlated with word span for both related and unrelated conditions, suggesting a strategy of narrowing response alternatives based upon memory for the set of item names. Evidence for a role of inhibition in response selection was obtained, as Stroop interference correlated positively with the change in naming latencies across cycles for the related, but not unrelated, condition. In contrast, recent negatives interference correlated negatively with the change in naming latencies across unrelated cycles, suggesting that individual differences in this tap the degree of strengthening of links in a lexical network based upon prior exposure. Results are discussed in terms of current models of lexical selection and consequences for word retrieval in more naturalistic production.

  10. Manipulation of a quasi-natural cell block for high-efficiency transplantation of adherent somatic cells

    Directory of Open Access Journals (Sweden)

    H.J. Chung

    2015-05-01

    Full Text Available Recent advances have raised hope that transplantation of adherent somatic cells could provide dramatic new therapies for various diseases. However, current methods for transplanting adherent somatic cells are not efficient enough for therapeutic applications. Here, we report the development of a novel method to generate quasi-natural cell blocks for high-efficiency transplantation of adherent somatic cells. The blocks were created by providing a unique environment in which cultured cells generated their own extracellular matrix. Initially, stromal cells isolated from mice were expanded in vitro in liquid cell culture medium followed by transferring the cells into a hydrogel shell. After incubation for 1 day with mechanical agitation, the encapsulated cell mass was perforated with a thin needle and then incubated for an additional 6 days to form a quasi-natural cell block. Allograft transplantation of the cell block into C57BL/6 mice resulted in perfect adaptation of the allograft and complete integration into the tissue of the recipient. This method could be widely applied for repairing damaged cells or tissues, stem cell transplantation, ex vivo gene therapy, or plastic surgery.

  11. Manipulation of a quasi-natural cell block for high-efficiency transplantation of adherent somatic cells.

    Science.gov (United States)

    Chung, H J; Hassan, M M; Park, J O; Kim, H J; Hong, S T

    2015-05-01

    Recent advances have raised hope that transplantation of adherent somatic cells could provide dramatic new therapies for various diseases. However, current methods for transplanting adherent somatic cells are not efficient enough for therapeutic applications. Here, we report the development of a novel method to generate quasi-natural cell blocks for high-efficiency transplantation of adherent somatic cells. The blocks were created by providing a unique environment in which cultured cells generated their own extracellular matrix. Initially, stromal cells isolated from mice were expanded in vitro in liquid cell culture medium followed by transferring the cells into a hydrogel shell. After incubation for 1 day with mechanical agitation, the encapsulated cell mass was perforated with a thin needle and then incubated for an additional 6 days to form a quasi-natural cell block. Allograft transplantation of the cell block into C57BL/6 mice resulted in perfect adaptation of the allograft and complete integration into the tissue of the recipient. This method could be widely applied for repairing damaged cells or tissues, stem cell transplantation, ex vivo gene therapy, or plastic surgery. PMID:25742639

  12. Organic photosensitive cells having a reciprocal-carrier exciton blocking layer

    Science.gov (United States)

    Rand, Barry P.; Forrest, Stephen R.; Thompson, Mark E.

    2007-06-12

    A photosensitive cell includes an anode and a cathode; a donor-type organic material and an acceptor-type organic material forming a donor-acceptor junction connected between the anode and the cathode; and an exciton blocking layer connected between the acceptor-type organic material of the donor-acceptor junction and the cathode, the blocking layer consisting essentially of a material that has a hole mobility of at least 10.sup.-7 cm.sup.2/V-sec or higher, where a HOMO of the blocking layer is higher than or equal to a HOMO of the acceptor-type material.

  13. Fine needle aspiration cytology and cell block in the diagnosis of seminoma testis

    Directory of Open Access Journals (Sweden)

    Abhishant Pandey

    2011-01-01

    Full Text Available Testicular neoplasms which show a wide variety of morphologic types, comprise a small proportion of malignancies. Early identification and treatment is essential for achieving long term survival. The cytologic findings in fine needle aspiration smears from left testicular swelling of a 49 year old male suggestive of a germ cell tumor was complimented by cell block preparation as seminoma. This was confirmed by histopathologic studies. We are presenting this case to emphasize that cell block can be used for diagnosis of testicular tumors.

  14. Diagnostic Value of Processing Cytologic Aspirates of Renal Tumors in Agar Cell (Tissue) Blocks

    DEFF Research Database (Denmark)

    Smedts, F.; Schrik, M.; Horn, T.;

    2010-01-01

    cells to formulate a diagnosis; the conventional cytologic sample in this case contained enough diagnostic cells. In all cases the AM diagnosis was confirmed in the definitive surgical specimen. Conclusion Our AM technique for processing fine needle aspirates from renal tumors results in a major......-initiated, and in 14% too few diagnostic cells were present in the conventional smears for cytologic diagnosis. It was, however, possible to correctly diagnose histologic sections from 97% of AM tissue blocks. In 11 cases this was facilitated with immunochemistry. In only 1 case did the AM tissue block contain too few...

  15. Production in a factory (the cell) requires high level of organisation : the cell: The plant’s smallest building block

    NARCIS (Netherlands)

    Heuvelink, E.

    2015-01-01

    The cell is the plant’s smallest building block. Many cultivation techniques and climate control measures have an effect at this level. Some knowledge about the functioning of the cell is therefore very useful. Many components of the cell have bizarre names so to understand it all better, for the pu

  16. Effect of nanoscale morphology on selective ethanol transport through block copolymer membranes

    Science.gov (United States)

    We report on the effect of block copolymer domain size on transport of liquid mixtures through the membranes by presenting pervaporation data of an 8 wt% ethanol/water mixture through A-B-A and B-A-B triblock copolymer membranes. The A-block was chosen to facilitate ethanol transport while the B-blo...

  17. Cell Selection Using Recursive Bipartite Matching

    DEFF Research Database (Denmark)

    Zakrzewska, Anna; Ruepp, Sarah Renée; Berger, Michael Stübert

    Wireless communication network consist nowadays of multiple standards, as well as cells of different sizes and coverage. Providing the best connection in such environment is a challenging task. We propose a new approach of solving the cell selection problem in heterogeneous networks. The method...

  18. Selective cell targeting and lineage tracing of human induced pluripotent stem cells using recombinant avian retroviruses.

    Science.gov (United States)

    Hildebrand, Laura; Seemann, Petra; Kurtz, Andreas; Hecht, Jochen; Contzen, Jörg; Gossen, Manfred; Stachelscheid, Harald

    2015-12-01

    Human induced pluripotent stem cells (hiPSC) differentiate into multiple cell types. Selective cell targeting is often needed for analyzing gene function by overexpressing proteins in a distinct population of hiPSC-derived cell types and for monitoring cell fate in response to stimuli. However, to date, this has not been possible, as commonly used viruses enter the hiPSC via ubiquitously expressed receptors. Here, we report for the first time the application of a heterologous avian receptor, the tumor virus receptor A (TVA), to selectively transduce TVA(+) cells in a mixed cell population. Expression of the TVA surface receptor via genetic engineering renders cells susceptible for infection by avian leucosis virus (ALV). We generated hiPSC lines with this stably integrated, ectopic TVA receptor gene that expressed the receptor while retaining pluripotency. The undifferentiated hiPSC(TVA+) as well as their differentiating progeny could be infected by recombinant ALV (so-called RCAS virus) with high efficiency. Due to incomplete receptor blocking, even sequential infection of differentiating or undifferentiated TVA(+) cells was possible. In conclusion, the TVA/RCAS system provides an efficient and gentle gene transfer system for hiPSC and extends our possibilities for selective cell targeting and lineage tracing studies.

  19. Medial amygdala lesions selectively block aversive Pavlovian-instrumental transfer in rats.

    Directory of Open Access Journals (Sweden)

    Margaret Grace McCue

    2014-09-01

    Full Text Available Pavlovian conditioned stimuli (CSs play an important role in the reinforcement and motivation of instrumental active avoidance (AA. Conditioned threats can also invigorate ongoing AA responding (aversive Pavlovian-instrumental transfer or PIT. The neural circuits mediating AA are poorly understood, although lesion studies suggest that lateral, basal and central amygdala nuclei, as well as infralimbic prefrontal cortex, make key, and sometimes opposing, contributions. We recently completed an extensive analysis of brain c-Fos expression in good vs. poor avoiders following an AA test (Martinez et al 2013, Learning and Memory. This analysis identified medial amygdala (MeA as a potentially important region for Pavlovian motivation of instrumental actions. MeA is known to mediate defensive responding to innate threats as well as social behaviors, but its role in mediating aversive Pavlovian-instrumental interactions is unknown. We evaluated the effect of MeA lesions on Pavlovian conditioning, Sidman two-way AA conditioning (shuttling and aversive PIT in rats. Mild footshocks served as the unconditioned stimulus in all conditioning phases. MeA lesions had no effect on AA but blocked the expression of aversive PIT and 22 kHz ultrasonic vocalizations in the AA context. Interestingly, MeA lesions failed to affect Pavlovian freezing to discrete threats but reduced freezing to contextual threats when assessed outside of the AA chamber. These findings differentiate MeA from lateral and central amygdala, as lesions of these nuclei disrupt Pavlovian freezing and aversive PIT, but have opposite effects on AA performance. Taken together, these results suggest that MeA plays a selective role in the motivation of instrumental avoidance by general or uncertain Pavlovian threats.

  20. Blocking peptides against HBV: PreS1 protein selected from a phage display library

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Wei; Liu, Yang; Zu, Xiangyang; Jin, Rui [State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071 (China); Xiao, Gengfu, E-mail: xiaogf@wh.iov.cn [State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071 (China)

    2011-09-09

    Highlights: {yields} Successfully selected specific PreS1-interacting peptides by using phage displayed library. {yields} Alignment of the positive phage clones revealed a consensus PreS1 binding motif. {yields} A highly enriched peptide named P7 had a strong binding ability for PreS1. {yields} P7 could block PreS1 attachment. -- Abstract: The PreS1 protein is present on the outermost part of the hepatitis B virus (HBV) surface and has been shown to have a pivotal function in viral infectivity and assembly. The development of reagents with high affinity and specificity for PreS1 is of great significance for early diagnosis and treatment of HBV infection. A phage display library of dodecapeptide was screened for interactions with purified PreS1 protein. Alignment of the positive phage clones revealed a putative consensus PreS1 binding motif of HX{sub n}HX{sub m}HP/R. Moreover, a peptide named P7 (KHMHWHPPALNT) was highly enriched and occurred with a surprisingly high frequency of 72%. A thermodynamic study revealed that P7 has a higher binding affinity to PreS1 than the other peptides. Furthermore, P7 was able to abrogate the binding of HBV virions to the PreS1 antibody, suggesting that P7 covers key functional sites on the native PreS1 protein. This newly isolated peptide may, therefore, be a new therapeutic candidate for the treatment of HBV. The consensus motif could be modified to deliver imaging, diagnostic, and therapeutic agents to tissues affected by HBV.

  1. M cell-depletion blocks oral prion disease pathogenesis

    OpenAIRE

    Donaldson, D S; Kobayashi, A; Ohno, H.; Yagita, H; Williams, I R; Mabbott, N A

    2012-01-01

    Many prion diseases are orally acquired. Our data show that after oral exposure, early prion replication upon follicular dendritic cells (FDC) in Peyer's patches is obligatory for the efficient spread of disease to the brain (termed neuroinvasion). For prions to replicate on FDC within Peyer's patches after ingestion of a contaminated meal, they must first cross the gut epithelium. However, the mechanism through which prions are conveyed into Peyer's patches is uncertain. Within the follicle-...

  2. A New Cell Block Method for Multiple Immunohistochemical Analysis of Circulating Tumor Cells in Patients with Liver Cancer

    Science.gov (United States)

    Nam, Soo Jeong; Yeo, Hyun Yang; Chang, Hee Jin; Kim, Bo Hyun; Hong, Eun Kyung; Park, Joong-Won

    2016-01-01

    Purpose We developed a new method of detecting circulating tumor cells (CTCs) in liver cancer patients by constructing cell blocks from peripheral blood cells, including CTCs, followed by multiple immunohistochemical analysis. Materials and Methods Cell blockswere constructed from the nucleated cell pellets of peripheral blood afterremoval of red blood cells. The blood cell blocks were obtained from 29 patients with liver cancer, and from healthy donor blood spikedwith seven cell lines. The cell blocks and corresponding tumor tissues were immunostained with antibodies to seven markers: cytokeratin (CK), epithelial cell adhesion molecule (EpCAM), epithelial membrane antigen (EMA), CK18, α-fetoprotein (AFP), Glypican 3, and HepPar1. Results The average recovery rate of spiked SW620 cells from blood cell blocks was 91%. CTCs were detected in 14 out of 29 patients (48.3%); 11/23 hepatocellular carcinomas (HCC), 1/2 cholangiocarcinomas (CC), 1/1 combined HCC-CC, and 1/3 metastatic cancers. CTCs from 14 patients were positive for EpCAM (57.1%), EMA (42.9%), AFP (21.4%), CK18 (14.3%), Gypican3 and CK (7.1%, each), and HepPar1 (0%). Patients with HCC expressed EpCAM, EMA, CK18, and AFP in tissue and/or CTCs, whereas CK, HepPar1, and Glypican3 were expressed only in tissue. Only EMA was significantly associated with the expressions in CTC and tissue. CTC detection was associated with higher T stage and portal vein invasion in HCC patients. Conclusion This cell block method allows cytologic detection and multiple immunohistochemical analysis of CTCs. Our results show that tissue biomarkers of HCC may not be useful for the detection of CTC. EpCAM could be a candidate marker for CTCs in patients with HCC. PMID:27034142

  3. Space-Time Block Coding for Time Slotted CDMA Systems with Frequency-Selective Fading

    Institute of Scientific and Technical Information of China (English)

    WANGYingmin; YIKechu; NIUZhongxia; TIANHongxin

    2003-01-01

    The radio channel fading is one of the most important physical limitations for wireless mobile communications. Space-time coding is a coding technique that is designed for use with multiple transmit antennas and offers an effective transmit diversity technique to combat fading. However, most existing space-time coding schemes assume fiat fading that may not be valid for wideband wireless mobile communication channels. In this paper, a novel spacetime block coding scheme based on block processing is proposed for time slotted CDMA systems with frequencyselective fading. In order to get quasi-orthogonality, we encode the information based on the two data fields (blocks) of a burst, other than the symbols in a data field (block). As a consequence, it is convenient for block processing of joint detection which can be used with just some small modifications of the algorithms with no space-time coding. For decoding the new space time codes, block linear joint detection algorithms are developed. Then, we simplify these algorithms with an iterative procedure. With moderate iterative times, the computation complexity of the simplified algorithms is much less than that of the exact algorithms. Simulation results show that the performance of the simplified joint detection algorithms approximates to that of the exact ones.

  4. Self-assembly of monodisperse polymer microspheres from PPQ-b-PEG rod-coil block copolymers in selective solvents

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xueao; CHEN Ke; XIE Kai; LONG Yongfu

    2005-01-01

    Poly(phenylquinoline)-block-poly(ethylene glycol)(PPQ-b-PEG) rod-coil block copolymers possess the self-assembly behavior in selective solvents. The copolymers in the mixed solvents of V(trifluoroacetic acid, TFA):V(dichloromethane, DCM)=1:1 can self-assemble into polymer hollow microspheres with diameters of a few micrometers. The polymer hollow microspheres are monodisperse, and the diameters of them increase with an increased polymerization degree of the PPQ rigid-rod block. The solution concentration has no effect on the microsphere diameter, but spherical surface shows burrs when the solution concentration is too low. It has been found that the obtained dilute solution has the strongest absorption peak at 376 nm and strongest emission peak at 604 nm by the spectroscopy analysis.

  5. Target inhibition networks: predicting selective combinations of druggable targets to block cancer survival pathways.

    Directory of Open Access Journals (Sweden)

    Jing Tang

    Full Text Available A recent trend in drug development is to identify drug combinations or multi-target agents that effectively modify multiple nodes of disease-associated networks. Such polypharmacological effects may reduce the risk of emerging drug resistance by means of attacking the disease networks through synergistic and synthetic lethal interactions. However, due to the exponentially increasing number of potential drug and target combinations, systematic approaches are needed for prioritizing the most potent multi-target alternatives on a global network level. We took a functional systems pharmacology approach toward the identification of selective target combinations for specific cancer cells by combining large-scale screening data on drug treatment efficacies and drug-target binding affinities. Our model-based prediction approach, named TIMMA, takes advantage of the polypharmacological effects of drugs and infers combinatorial drug efficacies through system-level target inhibition networks. Case studies in MCF-7 and MDA-MB-231 breast cancer and BxPC-3 pancreatic cancer cells demonstrated how the target inhibition modeling allows systematic exploration of functional interactions between drugs and their targets to maximally inhibit multiple survival pathways in a given cancer type. The TIMMA prediction results were experimentally validated by means of systematic siRNA-mediated silencing of the selected targets and their pairwise combinations, showing increased ability to identify not only such druggable kinase targets that are essential for cancer survival either individually or in combination, but also synergistic interactions indicative of non-additive drug efficacies. These system-level analyses were enabled by a novel model construction method utilizing maximization and minimization rules, as well as a model selection algorithm based on sequential forward floating search. Compared with an existing computational solution, TIMMA showed both enhanced

  6. Sensitivity Analysis of Centralized Dynamic Cell Selection

    DEFF Research Database (Denmark)

    Lopez, Victor Fernandez; Alvarez, Beatriz Soret; Pedersen, Klaus I.;

    2016-01-01

    and a suboptimal optimization algorithm that nearly achieves the performance of the optimal Hungarian assignment. Moreover, an exhaustive sensitivity analysis with different network and traffic configurations is carried out in order to understand what conditions are more appropriate for the use of the proposed...... with two different traffic models, and it is not necessary to be able to connect to a large number of cells in order to reap most of the benefits of the centralized dynamic cell selection....

  7. Electrochemical Characterization of TiO 2 Blocking Layers for Dye-Sensitized Solar Cells

    KAUST Repository

    Kavan, Ladislav

    2014-07-31

    Thin compact layers of TiO2 are grown by thermal oxidation of Ti, by spray pyrolysis, by electrochemical deposition, and by atomic layer deposition. These layers are used in dye-sensitized solar cells to prevent recombination of electrons from the substrate (FTO or Ti) with the hole-conducting medium at this interface. The quality of blocking is evaluated electrochemically by methylviologen, ferro/ferricyanide, and spiro-OMeTAD as the model redox probes. Two types of pinholes in the blocking layers are classified, and their effective area is quantified. Frequency-independent Mott-Schottky plots are fitted from electrochemical impedance spectroscopy. Certain films of the thicknesses of several nanometers allow distinguishing the depletion layer formation both in the TiO2 film and in the FTO substrate underneath the titania film. The excellent blocking function of thermally oxidized Ti, electrodeposited film (60 nm), and atomic-layer-deposited films (>6 nm) is documented by the relative pinhole area of less than 1%. However, the blocking behavior of electrodeposited and atomic-layer-deposited films is strongly reduced upon calcination at 500 °C. The blocking function of spray-pyrolyzed films is less good but also less sensitive to calcination. The thermally oxidized Ti is well blocking and insensitive to calcination. © 2014 American Chemical Society.

  8. Selective directed self-assembly of coexisting morphologies using block copolymer blends

    Science.gov (United States)

    Stein, A.; Wright, G.; Yager, K. G.; Doerk, G. S.; Black, C. T.

    2016-08-01

    Directed self-assembly (DSA) of block copolymers is an emergent technique for nano-lithography, but is limited in the range of structures possible in a single fabrication step. Here we expand on traditional DSA chemical patterning. A blend of lamellar- and cylinder-forming block copolymers assembles on specially designed surface chemical line gratings, leading to the simultaneous formation of coexisting ordered morphologies in separate areas of the substrate. The competing energetics of polymer chain distortions and chemical mismatch with the substrate grating bias the system towards either line/space or dot array patterns, depending on the pitch and linewidth of the prepattern. This is in contrast to the typical DSA, wherein assembly of a single-component block copolymer on chemical templates generates patterns of either lines/spaces (lamellar) or hexagonal dot arrays (cylinders). In our approach, the chemical template encodes desired local spatial arrangements of coexisting design motifs, self-assembled from a single, sophisticated resist.

  9. Selectivity in associative learning: A cognitive stage framework for blocking and cue competition phenomena

    Directory of Open Access Journals (Sweden)

    Yannick eBoddez

    2014-11-01

    Full Text Available Blocking is the most important phenomenon in the history of associative learning theory: For over 40 years, blocking has inspired a whole generation of learning models. Blocking is part of a family of effects that are typically termed cue competition effects. Common amongst all cue competition effects is that a cue-outcome relation is poorly learned or poorly expressed because the cue is trained in the presence of an alternative predictor or cause of the outcome. We provide an overview of the cognitive processes involved in cue competition effects in humans and propose a stage framework that brings these processes together. The framework contends that the behavioral display of cue competition is cognitively construed following three stages that include (1 an encoding stage, (2 a retention stage, and (3 a performance stage. We argue that the stage framework supports a comprehensive understanding of cue competition effects.

  10. In vitro immunological effects of blocking CCR5 on T cells.

    Science.gov (United States)

    Yuan, Jing; Ren, Han-Yun; Shi, Yong-Jin; Liu, Wei

    2015-04-01

    Blockade of CC chemokine receptor 5 (CCR5) by maraviroc may induce immunological changes independent of its antiviral effects and may have immunoregulation properties. This study was designed to determine the effects of blocking CCR5 on human activated T cells in vitro and investigate the potential immunological mechanisms. Human CD3+ T cells were purified from peripheral blood mononuclear cells and then activated by cytokines. We tested the surface expressions and relative messenger RNA (mRNA) levels of CCR2, CCR5, CCR6, CCR7, and CXCR3, chemotaxis toward their cognate ligands, internalization of chemokine receptors, and production of cytokines. In conclusion, blocking CCR5 by maraviroc not only can block CCR5 and CCR2 internalization processes induced by CCL5 and CCL2, but also inhibit T cell chemotactic activities toward their cognate ligands, respectively. Moreover, blocking CCR5 with maraviroc at high doses tends to decrease the production of TNF-α and IFN-γ. In addition, there might be a form of cross talk between CCR5 and CCR2, and this may offer a novel immunological effect for blockade of CCR5.

  11. A Cocaine Hydrolase Engineered from Human Butyrylcholinesterase Selectively Blocks Cocaine Toxicity and Reinstatement of Drug Seeking in Rats

    OpenAIRE

    Brimijoin, Stephen; Gao, Yang; Anker, Justin J.; Gliddon, Luke A.; LaFleur, David; Shah, R.; Zhao, Qinghai; Singh, M; Carroll, Marilyn E.

    2008-01-01

    Successive rational mutations of human butyrylcholinesterase (BChE) followed by fusion to human serum albumin have yielded an efficient hydrolase that offers realistic options for therapy of cocaine overdose and abuse. This albumin-BChE prevented seizures in rats given a normally lethal cocaine injection (100 mg/kg, i.p.), lowered brain cocaine levels even when administered after the drug, and provided rescue after convulsions commenced. Moreover, it selectively blocked cocaine-induced reinst...

  12. CMOS compatible strategy based on selective atomic layer deposition of a hard mask for transferring block copolymer lithography patterns

    International Nuclear Information System (INIS)

    A generic, CMOS compatible strategy for transferring a block copolymer template to a semiconductor substrate is demonstrated. An aluminum oxide (Al2O3) hard mask is selectively deposited by atomic layer deposition in an organized array of holes obtained in a PS matrix via PS-b-PMMA self-assembly. The Al2O3 nanodots act as a highly resistant mask to plasma etching, and are used to pattern high aspect ratio (>10) silicon nanowires and nanopillars.

  13. Brevilin A, a novel natural product, inhibits janus kinase activity and blocks STAT3 signaling in cancer cells.

    Directory of Open Access Journals (Sweden)

    Xing Chen

    Full Text Available Signal abnormalities in human cells usually cause unexpected consequences for individual health. We focus on these kinds of events involved in JAK-STAT signal pathways, especially the ones triggered by aberrant activated STAT3, an oncoprotein which participates in essential processes of cell survival, growth and proliferation in many types of tumors, as well as immune diseases. By establishing a STAT3 signal based high-throughput drug screening system in human lung cancer A549 cells, we have screened a library from natural products which contained purified compounds from medicinal herbs. One compound, named Brevilin A, exhibited both strong STAT3 signal inhibition and STAT3 signal dependent cell growth inhibition. Further investigations revealed that Brevilin A not only inhibits STAT3 signaling but also STAT1 signaling for cytokines induced phosphorylation of STAT3 and STAT1 as well as the expression of their target genes. In addition, we found Brevilin A could attenuate the JAKs activity by blocking the JAKs tyrosine kinase domain JH1. The levels of cytokine induced phosphorylation of STATs and other substrates were dramatically reduced by treatment of Brevilin A. The roles of Brevilin A targeting on JAKs activity indicate that Brevilin A may not only be used as a STAT3 inhibitor but also a compound blocking other JAK-STAT hyperactivation. Thus, these findings provided a strong impetus for the development of selective JAK-STAT inhibitors and therapeutic drugs in order to improve survival of patients with hyperactivated JAKs and STATs.

  14. PMC: Select Materialized Cells in Data Cubes

    Institute of Scientific and Technical Information of China (English)

    Hong-Song Li; Hou-Kuan Huang

    2006-01-01

    QC-Tree is one of the most storage-efficient structures for data cubes in an MOLAP system. Although QC-Tree can achieve a high compression ratio, it is still a fully materialized data cube. In this paper, an improved structure PMC is presented allowing us to materialize only a part of the cells in a QC-Tree to save more storage space. There is a notable difference between our partially materialization algorithm and traditional materialized views selection algorithms. In a traditional algorithm, when a view is selected, all the cells in this view are to be materialized. Otherwise, if a view is not selected, all the cells in this view will not be materialized. This strategy results in the unstable query performance. The presented algorithm, however, selects and materializes data in cell level, and, along with further reduced space and update cost, it can ensure a stable query performance. A series of experiments are conducted on both synthetic and real data sets. The results show that PMC can further reduce storage space occupied by the data cube, and can shorten the time to update the cube.

  15. Adapted cytokinesis-block micronucleus assay (CBMn) for mouse embryonic stem cells

    OpenAIRE

    sprotocols

    2015-01-01

    Authors: Hamid Kalantari, Hamid Gourabi & Hossein Baharvand ### Abstract Our observation showed the addition of cytochalasin-B to mouse embryonic stem cells (mESC) culture for CBMn analysis led to the induction of apoptosis in these cells. On the other hand, addition of cyt-B is the most critical part of the cytokinesis-block micronucleus assay (CBMn) technique that cannot be omitted. Thus, modification of the traditional CBMn assay seems to be necessary. In this paper, we attempt...

  16. Zn2+ blocks annealing of complementary single-stranded DNA in a sequence-selective manner

    Science.gov (United States)

    A simple low-temperature EDTA-free agarose gel electrophoresis procedure (LTEAGE) coupled with UV-Vis spectrum and fluorescence quenching analyses was developed and the Zn2+-single-stranded (ss) DNA interaction was investigated under near-physiological conditions. It was found that Zn2+ blocked the...

  17. Discrete-Time Block Models for Transmission Line Channels: Static and Doubly Selective Cases

    CERN Document Server

    Galli, Stefano

    2011-01-01

    Most methodologies for modeling Transmission Line (TL) based channels define the input-output relationship in the frequency domain (FD) and handle the TL resorting to a two-port network (2PN) formalism. These techniques have not yet been formally mapped into a discrete-time (DT) block model, which is useful to simulate and estimate the channel response as well as to design optimal precoding strategies. TL methods also fall short when they are applied to Time Varying (TV) systems, such as the power line channel. The objective of this paper is to establish if and how one can introduce a DT block model for the Power Line Channel. We prove that it is possible to use Lifting and Trailing Zeros (L&TZ) techniques to derive a DT block model that maps the TL-based input-output description directly in the time domain (TD) block channel model. More specifically, we find an interesting relationship between the elements of an ABCD matrix, defined in the FD, and filtering kernels that allow an elegant representation of...

  18. Sensitivity Analysis of Centralized Dynamic Cell Selection

    DEFF Research Database (Denmark)

    Lopez, Victor Fernandez; Alvarez, Beatriz Soret; Pedersen, Klaus I.;

    2016-01-01

    and a suboptimal optimization algorithm that nearly achieves the performance of the optimal Hungarian assignment. Moreover, an exhaustive sensitivity analysis with different network and traffic configurations is carried out in order to understand what conditions are more appropriate for the use of the proposed...... with two different traffic models, and it is not necessary to be able to connect to a large number of cells in order to reap most of the benefits of the centralized dynamic cell selection.......Centralized architectures with fronthauls can be used to deal with some of the problems inherently associated with dense small cell deployments. This study examines a joint cell assignment and scheduling solution for the downlink to increase the users’ data rates, based on cell switching...

  19. Application of a hybrid blocking layer in dye-sensitized solar cells

    OpenAIRE

    Lellig, P.

    2011-01-01

    In dye-sensitized solar cells a blocking layer between the transparent electrode and the mesoporous titanium dioxide film is used to prevent short-circuits between the hole-conductor and the front electrode. The conventional approach is to use a compact layer of titanium dioxide prepared by spin coating or spray pyrolysis. The thickness of the blocking layer is critical. On one hand, the layer has to be thick enough to cover the rough substrate completely. On the other hand, the serial resist...

  20. Sodium selectivity of semicircular canal duct epithelial cells

    Directory of Open Access Journals (Sweden)

    Harbidge Donald G

    2011-09-01

    Full Text Available Abstract Background Sodium absorption by semicircular canal duct (SCCD epithelial cells is thought to contribute to the homeostasis of the volume of vestibular endolymph. It was previously shown that the epithelial cells could absorb Na+ under control of a glucocorticoid hormone (dexamethasone and the absorptive transepithelial current was blocked by amiloride. The most commonly-observed target of amiloride is the epithelial sodium channel (ENaC, comprised of the three subunits α-, β- and γ-ENaC. However, other cation channels have also been observed to be sensitive in a similar concentration range. The aim of this study was to determine whether SCCD epithelial cells absorb only Na+ or also K+ through an amiloride-sensitive pathway. Parasensory K+ absorption could contribute to regulation of the transduction current through hair cells, as found to occur via vestibular transitional cells [S. H. Kim and D. C. Marcus. Regulation of sodium transport in the inner ear. Hear.Res. doi:10.1016/j.heares.2011.05.003, 2011]. Results We determined the molecular and functional expression of candidate cation channels with gene array (GEO GSE6197, whole-cell patch clamp and transepithelial recordings in primary cultures of rat SCCD. α-, β- and γ-ENaC were all previously reported as present. The selectivity of the amiloride-sensitive transepithelial and cell membrane currents was observed in Ussing chamber and whole-cell patch clamp recordings. The cell membrane currents were carried by Na+ but not K+, but the Na+ selectivity disappeared when the cells were cultured on impermeable supports. Transepithelial currents across SCCD were also carried exclusively by Na+. Conclusions These results are consistent with the amiloride-sensitive absorptive flux of SCCD mediated by a highly Na+-selective channel, likely αβγ-ENaC. These epithelial cells therefore absorb only Na+ via the amiloride-sensitive pathway and do not provide a parasensory K+ efflux from the

  1. Selective directed self-assembly of coexisting morphologies using block copolymer blends

    Science.gov (United States)

    Stein, A.; Wright, G.; Yager, K. G.; Doerk, G. S.; Black, C. T.

    2016-01-01

    Directed self-assembly (DSA) of block copolymers is an emergent technique for nano-lithography, but is limited in the range of structures possible in a single fabrication step. Here we expand on traditional DSA chemical patterning. A blend of lamellar- and cylinder-forming block copolymers assembles on specially designed surface chemical line gratings, leading to the simultaneous formation of coexisting ordered morphologies in separate areas of the substrate. The competing energetics of polymer chain distortions and chemical mismatch with the substrate grating bias the system towards either line/space or dot array patterns, depending on the pitch and linewidth of the prepattern. This is in contrast to the typical DSA, wherein assembly of a single-component block copolymer on chemical templates generates patterns of either lines/spaces (lamellar) or hexagonal dot arrays (cylinders). In our approach, the chemical template encodes desired local spatial arrangements of coexisting design motifs, self-assembled from a single, sophisticated resist. PMID:27480327

  2. Defective nonhomologous end joining blocks B-cell development in FLT3/ITD mice

    OpenAIRE

    Li, Li; Zhang, Li; Fan, Jinshui; Greenberg, Kathleen; Desiderio, Stephen; Rassool, Feyruz V.; Small, Donald

    2011-01-01

    We have generated an FLT3/ITD knock-in mouse model in which mice with an FLT3/ITD mutation develop myeloproliferative disease (MPD) and a block in early B-lymphocyte development. To elucidate the role of FLT3/ITD signaling in B-cell development, we studied VDJ recombination in the pro-B cells of FLT3/ITD mice and discovered an increased frequency of DNA double strand breaks (DSBs) introduced by the VDJ recombinase. Early pro-B cells from FLT3/ITD mice were found to have a lower efficiency and...

  3. Relationship Between Selected Strength and Power Assessments to Peak and Average Velocity of the Drive Block in Offensive Line Play.

    Science.gov (United States)

    Jacobson, Bert H; Conchola, Eric C; Smith, Doug B; Akehi, Kazuma; Glass, Rob G

    2016-08-01

    Jacobson, BH, Conchola, EC, Smith, DB, Akehi, K, and Glass, RG. Relationship between selected strength and power assessments to peak and average velocity of the drive block in offensive line play. J Strength Cond Res 30(8): 2202-2205, 2016-Typical strength training for football includes the squat and power clean (PC) and routinely measured variables include 1 repetition maximum (1RM) squat and 1RM PC along with the vertical jump (VJ) for power. However, little research exists regarding the association between the strength exercises and velocity of an actual on-the-field performance. The purpose of this study was to investigate the relationship of peak velocity (PV) and average velocity (AV) of the offensive line drive block to 1RM squat, 1RM PC, the VJ, body mass (BM), and body composition. One repetition maximum assessments for the squat and PC were recorded along with VJ height, BM, and percent body fat. These data were correlated with PV and AV while performing the drive block. Peal velocity and AV were assessed using a Tendo Power and Speed Analyzer as the linemen fired, from a 3-point stance into a stationary blocking dummy. Pearson product analysis yielded significant (p ≤ 0.05) correlations between PV and AV and the VJ, the squat, and the PC. A significant inverse association was found for both PV and AV and body fat. These data help to confirm that the typical exercises recommended for American football linemen is positively associated with both PV and AV needed for the drive block effectiveness. It is recommended that these exercises remain the focus of a weight room protocol and that ancillary exercises be built around these exercises. Additionally, efforts to reduce body fat are recommended.

  4. Microgravity-Enhanced Stem Cell Selection

    Science.gov (United States)

    Claudio, Pier Paolo; Valluri, Jagan

    2011-01-01

    Stem cells, both embryonic and adult, promise to revolutionize the practice of medicine in the future. In order to realize this potential, a number of hurdles must be overcome. Most importantly, the signaling mechanisms necessary to control the differentiation of stem cells into tissues of interest remain to be elucidated, and much of the present research on stem cells is focused on this goal. Nevertheless, it will also be essential to achieve large-scale expansion and, in many cases, assemble cells in 3D as transplantable tissues. To this end, microgravity analog bioreactors can play a significant role. Microgravity bioreactors were originally conceived as a tool to study the cellular responses to microgravity. However, the technology can address some of the shortcomings of conventional cell culture systems; namely, the deficiency of mass transport in static culture and high mechanical shear forces in stirred systems. Unexpectedly, the conditions created in the vessel were ideal for 3D cell culture. Recently, investigators have demonstrated the capability of the microgravity bioreactors to expand hematopoietic stem cells compared to static culture, and facilitate the differentiation of umbilical cord stem cells into 3D liver aggregates. Stem cells are capable of differentiating into functional cells. However, there are no reliable methods to induce the stem cells to form specific cells or to gain enough cells for transplantation, which limits their application in clinical therapy. The aim of this study is to select the best experimental setup to reach high proliferation levels by culturing these cells in a microgravity-based bioreactor. In typical cell culture, the cells sediment to the bottom surface of their container and propagate as a one-cell-layer sheet. Prevention of such sedimentation affords the freedom for self-assembly and the propagation of 3D tissue arrays. Suspension of cells is easily achievable using stirred technologies. Unfortunately, in

  5. Engineering novel cell surface chemistry for selective tumor cell targeting

    Energy Technology Data Exchange (ETDEWEB)

    Bertozzi, C.R. [Univ. of California, Berkeley, CA (United States)]|[Lawrence Berkeley National Lab., CA (United States)

    1997-12-31

    A common feature of many different cancers is the high expression level of the two monosaccharides sialic acid and fucose within the context of cell-surface associated glycoconjugates. A correlation has been made between hypersialylation and/or hyperfucosylation and the highly metastatic phenotype. Thus, a targeting strategy based on sialic acid or fucose expression would be a powerful tool for the development of new cancer cell-selective therapies and diagnostic agents. We have discovered that ketone groups can be incorporated metabolically into cell-surface associated sialic acids. The ketone is can be covalently ligated with hydrazide functionalized proteins or small molecules under physiological conditions. Thus, we have discovered a mechanism to selectively target hydrazide conjugates to highly sialylated cells such as cancer cells. Applications of this technology to the generation of novel cancer cell-selective toxins and MRI contrast reagents will be discussed, in addition to progress towards the use of cell surface fucose residues as vehicles for ketone expression.

  6. Development of Highly Selective Kv1.3-Blocking Peptides Based on the Sea Anemone Peptide ShK

    Directory of Open Access Journals (Sweden)

    Michael W. Pennington

    2015-01-01

    Full Text Available ShK, from the sea anemone Stichodactyla helianthus, is a 35-residue disulfide-rich peptide that blocks the voltage-gated potassium channel Kv1.3 at ca. 10 pM and the related channel Kv1.1 at ca. 16 pM. We developed an analog of this peptide, ShK-186, which is currently in Phase 1b-2a clinical trials for the treatment of autoimmune diseases such as multiple sclerosis and rheumatoid arthritis. While ShK-186 displays a >100-fold improvement in selectivity for Kv1.3 over Kv1.1 compared with ShK, there is considerable interest in developing peptides with an even greater selectivity ratio. In this report, we describe several variants of ShK that incorporate p-phophono-phenylalanine at the N-terminus coupled with internal substitutions at Gln16 and Met21. In addition, we also explored the combinatorial effects of these internal substitutions with an alanine extension at the C-terminus. Their selectivity was determined by patch-clamp electrophysiology on Kv1.3 and Kv1.1 channels stably expressed in mouse fibroblasts. The peptides with an alanine extension blocked Kv1.3 at low pM concentrations and exhibited up to 2250-fold selectivity for Kv1.3 over Kv1.1. Analogs that incorporates p-phosphono-phenylalanine at the N-terminus blocked Kv1.3 with IC50s in the low pM range and did not affect Kv1.1 at concentrations up to 100 nM, displaying a selectivity enhancement of >10,000-fold for Kv1.3 over Kv1.1. Other potentially important Kv channels such as Kv1.4 and Kv1.6 were only partially blocked at 100 nM concentrations of each of the ShK analogs.

  7. Selected problems relating to the dynamics of block-type foundations for machines

    Directory of Open Access Journals (Sweden)

    Marek Zombroń

    2014-07-01

    Full Text Available Atypical but real practical problems relating to the dynamics of block-type foundations for machines are considered using the deterministic approach and assuming that the determined parameters are random variables. A foundation model in the form of an undeformable solid on which another undeformable solid modelling a machine is mounted via viscoelastic constraints was adopted. The dynamic load was defined by a harmonically varying signal and by a series of short duration signals. The vibration of the system was investigated for the case when stratified ground (groundwater occurred within the side backfill was present. Calculation results illustrating the theoretical analyses are presented.

  8. Thermally induced structural evolution and performance of mesoporous block copolymer-directed alumina perovskite solar cells.

    KAUST Repository

    Tan, Kwan Wee

    2014-04-11

    Structure control in solution-processed hybrid perovskites is crucial to design and fabricate highly efficient solar cells. Here, we utilize in situ grazing incidence wide-angle X-ray scattering and scanning electron microscopy to investigate the structural evolution and film morphologies of methylammonium lead tri-iodide/chloride (CH3NH3PbI(3-x)Cl(x)) in mesoporous block copolymer derived alumina superstructures during thermal annealing. We show the CH3NH3PbI(3-x)Cl(x) material evolution to be characterized by three distinct structures: a crystalline precursor structure not described previously, a 3D perovskite structure, and a mixture of compounds resulting from degradation. Finally, we demonstrate how understanding the processing parameters provides the foundation needed for optimal perovskite film morphology and coverage, leading to enhanced block copolymer-directed perovskite solar cell performance.

  9. Facial Action and Emotional Language: ERP Evidence that Blocking Facial Feedback Selectively Impairs Sentence Comprehension.

    Science.gov (United States)

    Davis, Joshua D; Winkielman, Piotr; Coulson, Seana

    2015-11-01

    There is a lively and theoretically important debate about whether, how, and when embodiment contributes to language comprehension. This study addressed these questions by testing how interference with facial action impacts the brain's real-time response to emotional language. Participants read sentences about positive and negative events (e.g., "She reached inside the pocket of her coat from last winter and found some (cash/bugs) inside it.") while ERPs were recorded. Facial action was manipulated within participants by asking participants to hold chopsticks in their mouths using a position that allowed or blocked smiling, as confirmed by EMG. Blocking smiling did not influence ERPs to the valenced words (e.g., cash, bugs) but did influence ERPs to final words of sentences describing positive events. Results show that affectively positive sentences can evoke smiles and that such facial action can facilitate the semantic processing indexed by the N400 component. Overall, this study offers causal evidence that embodiment impacts some aspects of high-level comprehension, presumably involving the construction of the situation model.

  10. Decoy receptors block TRAIL sensitivity at a supracellular level: the role of stromal cells in controlling tumour TRAIL sensitivity.

    Science.gov (United States)

    O'Leary, L; van der Sloot, A M; Reis, C R; Deegan, S; Ryan, A E; Dhami, S P S; Murillo, L S; Cool, R H; Correa de Sampaio, P; Thompson, K; Murphy, G; Quax, W J; Serrano, L; Samali, A; Szegezdi, E

    2016-03-10

    Tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) is a death ligand cytokine known for its cytotoxic activity against malignantly transformed cells. TRAIL induces cell death through binding to death receptors DR4 and DR5. The inhibitory decoy receptors (DcR1 and DcR2) co-expressed with death receptor 4 (DR4)/DR5 on the same cell can block the transmission of the apoptotic signal. Here, we show that DcRs also regulate TRAIL sensitivity at a supracellular level and thus represent a mechanism by which the microenvironment can diminish tumour TRAIL sensitivity. Mathematical modelling and layered or spheroid stroma-extracellular matrix-tumour cultures were used to model the tumour microenvironment. By engineering TRAIL to escape binding by DcRs, we found that DcRs do not only act in a cell-autonomous or cis-regulatory manner, but also exert trans-cellular regulation originating from stromal cells and affect tumour cells, highlighting the potent inhibitory effect of DcRs in the tumour tissue and the necessity of selective targeting of the two death-inducing TRAIL receptors to maximise efficacy. PMID:26050621

  11. CMOS compatible strategy based on selective atomic layer deposition of a hard mask for transferring block copolymer lithography patterns

    Energy Technology Data Exchange (ETDEWEB)

    Gay, G; Grampeix, H; Martin, F; Jalaguier, E; De Salvo, B [CEA LETI MINATEC, 17 rue des Martyrs, 38054 Grenoble (France); Baron, T; Agraffeil, C; Salhi, B; Chevolleau, T; Cunge, G; Tortai, J-H, E-mail: guillaume.gay@cea.fr, E-mail: thierry.baron@cea.fr [CNRS-LTM, 17 rue des Martyrs, 38054 Grenoble (France)

    2010-10-29

    A generic, CMOS compatible strategy for transferring a block copolymer template to a semiconductor substrate is demonstrated. An aluminum oxide (Al{sub 2}O{sub 3}) hard mask is selectively deposited by atomic layer deposition in an organized array of holes obtained in a PS matrix via PS-b-PMMA self-assembly. The Al{sub 2}O{sub 3} nanodots act as a highly resistant mask to plasma etching, and are used to pattern high aspect ratio (>10) silicon nanowires and nanopillars.

  12. Atomic layer deposition of ultrathin blocking layer for low-temperature solid oxide fuel cell on nanoporous substrate

    International Nuclear Information System (INIS)

    An ultrathin yttria-stabilized zirconia (YSZ) blocking layer deposited by atomic layer deposition (ALD) was utilized for improving the performance and reliability of low-temperature solid oxide fuel cells (SOFCs) supported by an anodic aluminum oxide substrate. Physical vapor-deposited YSZ and gadolinia-doped ceria (GDC) electrolyte layers were deposited by a sputtering method. The ultrathin ALD YSZ blocking layer was inserted between the YSZ and GDC sputtered layers. To investigate the effects of an inserted ultrathin ALD blocking layer, SOFCs with and without an ultrathin ALD blocking layer were electrochemically characterized. The open circuit voltage (1.14 V) of the ALD blocking-layered SOFC was visibly higher than that (1.05 V) of the other cell. Furthermore, the ALD blocking layer augmented the power density and improved the reproducibility

  13. Atomic layer deposition of ultrathin blocking layer for low-temperature solid oxide fuel cell on nanoporous substrate

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Wonjong; Cho, Gu Young; Noh, Seungtak; Tanveer, Waqas Hassan; Cha, Suk Won, E-mail: swcha@snu.ac.kr [School of Mechanical and Aerospace Engineering, Seoul National University, San 56-1, Daehak dong, Gwanak-gu, Seoul 151-742 (Korea, Republic of); Ji, Sanghoon [Graduate School of Convergence Science and Technology, Seoul National University, 864-1, Iui-dong, Yeongtong-gu, Suwon 443-270 (Korea, Republic of); An, Jihwan [Manufacturing Systems and Design Engineering Program, Seoul National University of Science and Technology, 232 Gongneung-ro, Nowon-gu, Seoul 139-743 (Korea, Republic of)

    2015-01-15

    An ultrathin yttria-stabilized zirconia (YSZ) blocking layer deposited by atomic layer deposition (ALD) was utilized for improving the performance and reliability of low-temperature solid oxide fuel cells (SOFCs) supported by an anodic aluminum oxide substrate. Physical vapor-deposited YSZ and gadolinia-doped ceria (GDC) electrolyte layers were deposited by a sputtering method. The ultrathin ALD YSZ blocking layer was inserted between the YSZ and GDC sputtered layers. To investigate the effects of an inserted ultrathin ALD blocking layer, SOFCs with and without an ultrathin ALD blocking layer were electrochemically characterized. The open circuit voltage (1.14 V) of the ALD blocking-layered SOFC was visibly higher than that (1.05 V) of the other cell. Furthermore, the ALD blocking layer augmented the power density and improved the reproducibility.

  14. A PCNA-derived cell permeable peptide selectively inhibits neuroblastoma cell growth.

    Directory of Open Access Journals (Sweden)

    Long Gu

    Full Text Available Proliferating cell nuclear antigen (PCNA, through its interaction with various proteins involved in DNA synthesis, cell cycle regulation, and DNA repair, plays a central role in maintaining genome stability. We previously reported a novel cancer associated PCNA isoform (dubbed caPCNA, which was significantly expressed in a broad range of cancer cells and tumor tissues, but not in non-malignant cells. We found that the caPCNA-specific antigenic site lies between L126 and Y133, a region within the interconnector domain of PCNA that is known to be a major binding site for many of PCNA's interacting proteins. We hypothesized that therapeutic agents targeting protein-protein interactions mediated through this region may confer differential toxicity to normal and malignant cells. To test this hypothesis, we designed a cell permeable peptide containing the PCNA L126-Y133 sequence. Here, we report that this peptide selectively kills human neuroblastoma cells, especially those with MYCN gene amplification, with much less toxicity to non-malignant human cells. Mechanistically, the peptide is able to block PCNA interactions in cancer cells. It interferes with DNA synthesis and homologous recombination-mediated double-stranded DNA break repair, resulting in S-phase arrest, accumulation of DNA damage, and enhanced sensitivity to cisplatin. These results demonstrate conceptually the utility of this peptide for treating neuroblastomas, particularly, the unfavorable MYCN-amplified tumors.

  15. G2-block after irradiation of cells with different p53 status

    Energy Technology Data Exchange (ETDEWEB)

    Zoelzer, Friedo [University of South Bohemia in Ceske Budejovice, Department of Radiology, Toxicology and Civil Protection, Faculty of Health and Social Studies, Ceske Budejovice (Czech Republic); University Duisburg-Essen, Institute of Medical Radiobiology, Medical Faculty, Essen (Germany); Jagetia, Ganesh [University Duisburg-Essen, Institute of Medical Radiobiology, Medical Faculty, Essen (Germany); Mizoram University, Department of Zoology, School of Life Sciences, Aizawl (India); Streffer, Christian [University Duisburg-Essen, Institute of Medical Radiobiology, Medical Faculty, Essen (Germany)

    2014-11-15

    Although it is clear that functional p53 is not required for radiation-induced G{sub 2} block, certain experimental findings suggest a role for p53 in this context. For instance, as we also confirm here, the maximum accumulation in the G{sub 2} compartment after X-ray exposure occurs much later in p53 mutants than in wild types. It remains to be seen, however, whether this difference is due to a longer block in the G{sub 2} phase itself. We observed the movement of BrdU-labeled cells through G{sub 2} and M into G{sub 1}. From an analysis of the fraction of labeled cells that entered the second posttreatment cell cycle, we were able to determine the absolute duration of the G{sub 2} and M phases in unirradiated and irradiated cells. Our experiments with four cell lines, two melanomas and two squamous carcinomas, showed that the radiation-induced delay of transition through the G{sub 2} and M phases did not correlate with p53 status. We conclude that looking at the accumulation of cells in the G{sub 2} compartment alone is misleading when differences in the G{sub 2} block are investigated and that the G{sub 2} block itself is indeed independent of functional p53. (orig.) [German] Obwohl klar ist, dass ein funktionelles p53-Protein fuer die Ausbildung des strahleninduzierten G{sub 2}-Blocks nicht zwingend erforderlich ist, gibt es experimentelle Befunde, die nahe legen, dass p53 in diesem Zusammenhang doch eine gewisse Rolle spielt. Zum Beispiel bestaetigen wir hier fruehere Berichte, dass die Akkumulation von Zellen im G{sub 2}-Kompartiment bei p53-Mutanten deutlich spaeter nach Bestrahlung ihr Maximum erreicht als bei p53-Wildtypen. Es bleibt jedoch zu klaeren, ob dieser Unterschied seinen Grund in einem laengeren Block der G{sub 2}-Phase selbst hat. Beobachtet wurde die Bewegung von BrdU-markierten Zellen durch G{sub 2} und M nach G{sub 1}. Aus der zeitlichen Veraenderung des Anteils markierter Zellen im G{sub 1}-Kompartiment des naechsten Zellzyklus konnte die

  16. Block Copolymer Electrolytes: Thermodynamics, Ion Transport, and Use in Solid- State Lithium/Sulfur Cells

    Science.gov (United States)

    Teran, Alexander Andrew

    anode, the compatibility of the sulfur cathode was explored. The sulfur cathode presents many unique challenges, including the generation of soluble lithium polysulfides (Li2Sx, 2 ≤ x ≤ 8) during discharge. The solubility of such species in block copolymers and their effect on morphology was examined. The lithium polysulfides were found to exhibit similar solubility in the block copolymers as in typical organic electrolytes, however induced unusual and unexpected phase behavior in the block copolymers. Inspired by successful efforts to physically confine the soluble lithium polysulfides via nanostructured carbon-sulfur composites in the cathode, our nanostructured block copolymer electrolytes were employed in full electrochemical cells with a lithium metal anode and sulfur cathode. Different cathode compositions, electrolyte additives, and cell architectures were tested. Surprisingly, the polysulfides diffused readily from the cathode through the block copolymer electrolyte, and the normally robust SEO|Li metal interface was detrimentally affected their presence during cycling. The polysulfides appeared to change the mechanical properties of the electrolyte such that intimate contact with the lithium metal was lost. Several promising strategies to overcome this problem were investigated and offer exciting avenues for improvement for future researchers. (Abstract shortened by UMI.).

  17. Targeting host syntaxin-5 preferentially blocks Leishmania parasitophorous vacuole development in infected cells and limits experimental Leishmania infections.

    Science.gov (United States)

    Canton, Johnathan; Kima, Peter E

    2012-10-01

    Our previous observations established a role for syntaxin-5 in the development of Leishmania parasitophorous vacuoles (LPVs). In this study, we took advantage of the recent identification of Retro-2, a small organic molecule that can cause the redistribution of syntaxin-5; we show herein that Retro-2 blocks LPV development within 2 hours of adding it to cells infected with Leishmania amazonensis. In infected cells incubated for 48 hours with Retro-2, LPV development was significantly limited; furthermore, infected cells harbored four to five times fewer parasites than infected cells incubated in vehicle alone. In vivo studies revealed that Retro-2 curbed experimental L. amazonensis infections in a dose-dependent manner. Retro-2 did not have any appreciable effect on the host cell physiological characteristics; furthermore, it had no apparent toxicity in experimental animals. An unexpected, but welcome, finding was that Retro-2 inhibited the replication of Leishmania parasites in axenic cultures. This study is significant because it identifies an endoplasmic reticulum/Golgi SNARE as a potential target for the control of Leishmania infections; moreover, it suggests that small organic molecules can be identified that can selectively disrupt the vesicle fusion machinery that promotes the development of pathogen-containing compartments without exerting toxic effects on the host.

  18. Cytopathological evaluations combined RNA and protein analyses on defined cell regions using single frozen tissue block.

    Science.gov (United States)

    Li, Hong; Chen, Xiao Yan; Kong, Qing You; Liu, Jia

    2002-06-01

    The co-existence of multiple cell components in tissue samples is the main obstacle for precise molecular evaluation on defined cell types. Based on morphological examination, we developed an efficient approach for paralleled RNA and protein isolations from an identical histological region in frozen tissue section. The RNA and protein samples prepared were sufficient for RT-PCR and Western blot analyses, and the results obtained were well coincident each other as well as with the corresponding parameters revealed from immunohistochemical examinations. By this way, the sampling problem caused by cell-cross contamination can be largely avoided, committing the experimental data more specific to a defined cell type. These novel methods thus allow us to use single tissue block for a comprehensive study by integration of conventional cytological evaluations with nucleic acid and protein analyses.

  19. Cytopathological evaluations combined RNA and protein analyses on defined cell regions using single frozen tissue block

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The co-existence of multiple cell components in tissue samples is the main obstacle for precise molecular evaluation on defined cell types. Based on morphological examination, we developed an efficient approach for paralleled RNA and protein isolations from an identical histological region in frozen tissue section.The RNA and protein samples prepared were sufficient for RT-PCR and Western blot analyses, and the results obtained were well coincident each other as well as with the corresponding parameters revealed from immunohistochemical examinations. By this way, the sampling problem caused by cell-cross contamination can be largely avoided, committing the experimental data more specific to a defined cell type. These novel methods thus allow us to use single tissue block for a comprehensive study by integration of conventional cytological evaluations with nucleic acid and protein analyses.

  20. Contribution of ultrasound-guided fine-needle aspiration cell blocks of metastatic supraclavicular lymph nodes to the diagnosis of lung cancer

    Directory of Open Access Journals (Sweden)

    Hai-Ying Tian

    2015-01-01

    Conclusion: Cell-block samples from US-guided FNA is a promising, relatively noninvasive technique to provide additional information in lung cancer diagnosis. Analysis of cell blocks allows for genetic analysis of the patients with supraclavicular lymph nodes metastasis.

  1. CYTOKINESIS-BLOCK MICRONUCLEUS ASSAY IN HUMAN GLIOMA CELLS EXPOSED TO RADIATION

    Directory of Open Access Journals (Sweden)

    Jerzy Slowinski

    2011-05-01

    Full Text Available Biological tests are efficient in reflecting the biological influences of several types of generally harmful exposures. The micronucleus assay is widely used in genotoxicity studies or studies on genomic damage in general. We present methodological aspects of cytokinesis-block micronucleus assay performed in human gliomas irradiated in vitro. Eight human glioblastoma cell lines obtained from DSMZ (Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH, Germany were gamma-irradiated (60Co over a dose range of 0-10 Gy. Cytokinesis-block micronucleus assay was performed to quantitate cytogenetic damage. The cells were fixed directly on dishes, stained with fluorochrome DAPI and evaluated under fluorescent and phase contrast microscope. The micronucleus frequency was expressed as a micronuclei (MN per binucleated cell (BNC ratio, calculated after scoring at least 100 BNC per dish. The frequency of spontaneous MN ranged from 0.17 to 0.613 (mean: 0.29 ± 0.14. After irradiation increase of MN frequency in the range of 0.312 - 2.241 (mean: 0.98 ± 0.68 was found at 10 Gy. Gliomas are extremely heterogenous in regard to cytogenetic effects of irradiation, as shown in this study by cytokinesis-block micronucleus assay. This test is easily performed on irradiated glioma cell lines and can assist in determining their radiosensitivity. However, in order to obtain reliable and reproducible results, precise criteria for MN scoring must be strictly followed. Simultaneous use of fluorescent and phase contrast equipment improves imaging of morphological details and can further optimize MN scoring.

  2. Corticosteroids reverse cytokine-induced block of survival and differentiation of oligodendrocyte progenitor cells from rats

    Directory of Open Access Journals (Sweden)

    Marx Romy

    2008-09-01

    protein. The most potent corticosteroid tested, dexamethasone, was shown to counteract cytokine effects on membrane surface extension and capacitance. Furthermore, coapplication of dexamethasone blocked the cytokine-induced downregulation of the inwardly rectifying potassium current in 80% of the precursor cells and restored the cytokine-blocked down-regulation of the voltage activated Na+- and K+ currents during subsequent differentiation. Conclusion Our results show that treatment of oligodendrocyte precursors with the inflammatory cytokines TNF-α and IFN-γ block the differentiation of oligodendrocyte precursors at the level of the differentiation of the voltage-gated ion currents. Co-treatment with corticosteroids at the time of cytokine application restores to a considerable extent survival and differentiation of oligodendrocytes at the level of morphological, myelin protein as well as ion current maturation suggesting the option for a functional restoration of cytokine-damaged immature oligodendrocytes.

  3. Variable selection in PLSR and extensions to a multi-block setting for metabolomics data

    DEFF Research Database (Denmark)

    Karaman, İbrahim; Hedemann, Mette Skou; Knudsen, Knud Erik Bach;

    of genomics [1]. They became quickly well established in the field of statistics because a close relationship to elastic net has been established. In sparse variable selection combined with PLSR, a soft thresholding is applied on each loading weight separately. In the field of chemometrics Jack-knifing has...... been introduced for variable selection in PLSR [2]. Jack-knifing has been frequently applied in the field of spectroscopy and is implemented in software tools like The Unscrambler. In Jack-knifing uncertainty estimates of regression coefficients are estimated and a t-test is applied on these estimates...... in order to assess whether the regression coefficient associated to each variable is significantly different from zero. In a recent study we have compared sparse PLSR [1] and Jack-knife PLSR for FTIR spectroscopic data, metabolomics data (LC-MS, NMR) and simulated data. While sparse PLSR turned out...

  4. EBP50 inhibits EGF-induced breast cancer cell proliferation by blocking EGFR phosphorylation.

    Science.gov (United States)

    Yao, Wenfang; Feng, Duiping; Bian, Weihua; Yang, Longyan; Li, Yang; Yang, Zhiyu; Xiong, Ying; Zheng, Junfang; Zhai, Renyou; He, Junqi

    2012-11-01

    Ezrin-radixin-moesin-binding phosphoprotein-50 (EBP50) suppresses breast cancer cell proliferation, potentially through its regulatory effect on epidermal growth factor receptor (EGFR) signaling, although the mechanism by which this occurs remains unknown. Thus in our studies, we aimed to determine the effect of EBP50 expression on EGF-induced cell proliferation and activation of EGFR signaling in the breast cancer cell lines, MDA-MB-231 and MCF-7. In MDA-MB-231 cells, which express low levels of EBP50, EBP50 overexpression inhibited EGF-induced cell proliferation, ERK1/2 and AKT phosphorylation. In MCF-7 cells, which express high levels of EBP50, EBP50 knockdown promoted EGF-induced cell proliferation, ERK1/2 and AKT phosphorylation. Knockdown of EBP50 in EBP50-overexpressed MDA-MB-231 cells abrogated the inhibitory effect of EBP50 on EGF-stimulated ERK1/2 phosphorylation and restoration of EBP50 expression in EBP50-knockdown MCF-7 cells rescued the inhibition of EBP50 on EGF-stimulated ERK1/2 phosphorylation, further confirming that the activation of EGF-induced downstream molecules could be specifically inhibited by EBP50 expression. Since EGFR signaling was triggered by EGF ligands via EGFR phosphorylation, we further detected the phosphorylation status of EGFR in the presence or absence of EBP50 expression. Overexpression of EBP50 in MDA-MB-231 cells inhibited EGF-stimulated EGFR phosphorylation, whereas knockdown of EBP50 in MCF-7 cells enhanced EGF-stimulated EGFR phosphorylation. Meanwhile, total expression levels of EGFR were unaffected during EGF stimulation. Taken together, our data shows that EBP50 can suppress EGF-induced proliferation of breast cancer cells by inhibiting EGFR phosphorylation and blocking EGFR downstream signaling in breast cancer cells. These results provide further insight into the molecular mechanism by which EBP50 regulates the development and progression of breast cancer.

  5. Blocking S1P interaction with S1P{sub 1} receptor by a novel competitive S1P{sub 1}-selective antagonist inhibits angiogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Fujii, Yasuyuki, E-mail: y.fujii@po.rd.taisho.co.jp [Department of Molecular Function and Pharmacology Laboratories, Taisho Pharmaceutical Co. Ltd., 1-403 Saitama, Saitama 331-9530 (Japan); Ueda, Yasuji; Ohtake, Hidenori; Ono, Naoya; Takayama, Tetsuo; Nakazawa, Kiyoshi [Department of Molecular Function and Pharmacology Laboratories, Taisho Pharmaceutical Co. Ltd., 1-403 Saitama, Saitama 331-9530 (Japan); Igarashi, Yasuyuki [Laboratory of Biomembrane and Biofunctional Chemistry, Hokkaido University, Sapporo, Hokkaido 060-0812 (Japan); Goitsuka, Ryo [Division of Development and Aging, Research Institute for Biological Sciences, Tokyo University of Science, Noda, Chiba 278-0022 (Japan)

    2012-03-23

    Highlights: Black-Right-Pointing-Pointer The effect of a newly developed S1P{sub 1}-selective antagonist on angiogenic responses. Black-Right-Pointing-Pointer S1P{sub 1} is a critical component of VEGF-related angiogenic responses. Black-Right-Pointing-Pointer S1P{sub 1}-selective antagonist showed in vitro activity to inhibit angiogenesis. Black-Right-Pointing-Pointer S1P{sub 1}-selective antagonist showed in vivo activity to inhibit angiogenesis. Black-Right-Pointing-Pointer The efficacy of S1P{sub 1}-selective antagonist for anti-cancer therapies. -- Abstract: Sphingosine 1-phosphate receptor type 1 (S1P{sub 1}) was shown to be essential for vascular maturation during embryonic development and it has been demonstrated that substantial crosstalk exists between S1P{sub 1} and other pro-angiogenic growth factors, such as vascular endothelial growth factor (VEGF) and basic fibroblast growth factor. We developed a novel S1P{sub 1}-selective antagonist, TASP0277308, which is structurally unrelated to S1P as well as previously described S1P{sub 1} antagonists. TASP0277308 inhibited S1P- as well as VEGF-induced cellular responses, including migration and proliferation of human umbilical vein endothelial cells. Furthermore, TASP0277308 effectively blocked a VEGF-induced tube formation in vitro and significantly suppressed tumor cell-induced angiogenesis in vivo. These findings revealed that S1P{sub 1} is a critical component of VEGF-related angiogenic responses and also provide evidence for the efficacy of TASP0277308 for anti-cancer therapies.

  6. Piperlongumine selectively kills cancer cells and increases cisplatin antitumor activity in head and neck cancer.

    Science.gov (United States)

    Roh, Jong-Lyel; Kim, Eun Hye; Park, Jin Young; Kim, Ji Won; Kwon, Minsu; Lee, Byung-Heon

    2014-10-15

    Adaptation to cellular stress is not a vital function of normal cells but is required of cancer cells, and as such might be a sensible target in cancer therapy. Piperlongumine is a naturally occurring small molecule selectively toxic to cancer cells. This study assesses the cytotoxicity of piperlongumine and its combination with cisplatin in head-and-neck cancer (HNC) cells in vitro and in vivo. The effect of piperlongumine, alone and in combination with cisplatin, was assessed in human HNC cells and normal cells by measuring growth, death, cell cycle progression, reactive oxygen species (ROS) production, and protein expression, and in tumor xenograft mouse models. Piperlongumine killed HNC cells regardless of p53 mutational status but spared normal cells. It increased ROS accumulation in HNC cells, an effect that can be blocked by the antioxidant N-acetyl-L-cysteine. Piperlongumine induced selective cell death in HNC cells by targeting the stress response to ROS, leading to the induction of death pathways involving JNK and PARP. Piperlongumine increased cisplatin-induced cytotoxicity in HNC cells in a synergistic manner in vitro and in vivo. Piperlongumine might be a promising small molecule with which to selectively kill HNC cells and increase cisplatin antitumor activity by targeting the oxidative stress response. PMID:25193861

  7. 324 and 325 Building Hot Cell Cleanout Program: Air lock cover block refurbishment

    International Nuclear Information System (INIS)

    The high-density concrete cover blocks shielding the pipe trench in the hot-cell air lock of the 324 Building Radiochemical Engineering Cells had accumulated fixed radioactivity ranging from 1100 to 22, 000 mrad/hr. A corresponding increase in the radiation exposure to personnel entering the air lock, together with ALARA concerns, led to the removal of the contaminated concrete surface with a hydraulic spaller and the emplacement of a stainless steel covering over a layer of grout. The resultant saving in radiation exposure is estimated to be 7200 mrad for personnel completing burial box runs for the 324 and 325 Building Hot Cell Cleanout Program. Radiation exposure to all staff members entering the air lock is now at least 50% lower. 3 refs., 22 figs., 1 tab

  8. Block copolymer directed synthesis of mesoporous TiO 2 for dye-sensitized solar cells

    KAUST Repository

    Nedelcu, Mihaela

    2009-01-01

    The morphology of TiO2 plays an important role in the operation of solid-state dye-sensitized solar cells. By using polyisoprene-block- ethyleneoxide (PI-b-PEO) copolymers as structure directing agents for a sol-gel based synthesis of mesoporous TiO2, we demonstrate a strategy for the detailed control of the semiconductor morphology on the 10 nm length scale. The careful adjustment of polymer molecular weight and titania precursor content is used to systematically vary the material structure and its influence upon solar cell performance is investigated. Furthermore, the use of a partially sp 2 hybridized structure directing polymer enables the crystallization of porous TiO2 networks at high temperatures without pore collapse, improving its performance in solid-state dye-sensitized solar cells. © 2009 The Royal Society of Chemistry.

  9. Block to influenza virus replication in cells preirradiated with ultraviolet light

    International Nuclear Information System (INIS)

    Ultraviolet (uv) irradiation of CEF cells immediately before infection with influenza A (fowl plague) virus inhibited virus growth; no inhibition of the growth of a parainfluenza virus (Newcastle disease virus) could be detected in irradiated cells. The kinetics of inhibition after various doses of uv irradiation were multihit, with an extrapolation number of two. When irradiated cells were allowed to photoreactivate by exposure to visible light for 16 hr their capacity to support influenza virus replication was largely restored; this process was sensitive to caffeine, suggesting that it required DNA repair. In CEF cells exposed to 360 ergs/mm2 of uv radiation the rate of synthesis of host cellular RNA was reduced by more than 90%, and that of host cellular protein by 40 to 50%, as judged by incorporation of precursor molecules into an acid-insoluble form. When such irradiated cells were infected with influenza virus all the genome RNA segments were transcribed, but the overall concentration of virus-specific poly(A)-containing cRNA was reduced about 50-fold. Within this population of cRNA molecules, the RNAs coding for late proteins (HA, NA, and M) were reduced in amount relative to the other segments. The rates of synthesis of the M and HA proteins were specifically reduced in uv-irradiated cells, but the rates of synthesis of the P, NP, and NS proteins were only slightly reduced compared to normal cells. Immunofluorescent studies showed that, in uv-irradiated cells, NP migrated into the nucleus early after infection and later migrated out into the cytoplasm, as in normal cells. In contrast to normal cells, no specific immunofluorescence associated with M protein could be observed in uv-irradiated cells. It is concluded that uv-induced damage to host cellular DNA alters the pattern of RNA transcription in CEF cells infected with influenza virus, and that this results in a block to late protein synthesis which stops virus production

  10. Subdural spread of injected local anesthetic in a selective transforaminal cervical nerve root block: a case report

    Directory of Open Access Journals (Sweden)

    Tofuku Katsuhiro

    2012-06-01

    Full Text Available Abstract Introduction Although uncommon, selective cervical nerve root blocks can have serious complications. The most serious complications that have been reported include cerebral infarction, spinal cord infarction, transient quadriplegia and death. Case presentation A 40-year-old Japanese woman with a history of severe right-sided cervical radicular pain was scheduled to undergo a right-sided C6 selective cervical nerve root block using a transforaminal approach under fluoroscopic guidance. An anterior oblique view of the C5-C6 intervertebral foramen was obtained, and a 23-gauge spinal needle, connected to the normal extension tube with a syringe filled with contrast medium, was introduced into the posterior-caudal aspect of the C5-C6 intervertebral foramen on the right side. In the anteroposterior view, the placement of the needle was considered satisfactory when it was placed no more medial than halfway across the width of the articular pillar. Although the spread of the contrast medium along the C6 nerve root was observed with right-sided C6 radiculography, the subdural flow of the contrast medium was not observed with real-time fluoroscopy. The extension tube used for the radiculography was removed from the spinal needle and a normal extension tube with a syringe filled with lidocaine connected in its place. We performed a negative aspiration test and then injected 1.5 mL of 1.0% lidocaine slowly around the C6 nerve root. Immediately after the injection of the local anesthetic, our patient developed acute flaccid paralysis, complained of breathing difficulties and became unresponsive; her respiratory pattern was uncoordinated. After 20 minutes, she regained consciousness and became alert, and her muscle strength in all four limbs returned to normal without any sensory deficits after receiving emergent cardiorespiratory support. Conclusions We believe that confirming maintenance of the appropriate needle position in the anteroposterior

  11. Adipose stromal cells-conditioned medium blocks 6-hydroxydopamine-induced neurotoxicity and reactive oxygen species.

    Science.gov (United States)

    Gu, Huiying; Wang, Jimmy; Du, Nicole; Tan, Jiangning; Johnstone, Brian; Du, Yansheng

    2013-06-01

    A recent in vivo study suggested that the delivery of adipose stromal cells (ASCs) protected rat brains from 6-hydroxydopamine (6-OHDA)-induced neurotoxicity. However, the molecular mechanism that underlies this neuroprotection remains unknown. It was suggested that ASCs-induced neuroprotection possibly resulting from released factors from ASCs. In this study, we investigated whether and how cell-free conditioned media collected from ASCs (ASC-CM) protect neurons against neurotoxicity induced by 6-OHDA in cultured rat rostral mesencephalic neurons (RMN) and cerebellar granule neurons (CGN). We now report that ASC-CM protects both RMN and CGN against 6-OHDA neurotoxicity. Exposure of CGN to 6-OHDA resulted in a significant increases in neuronal ROS and cell death. As expected, pretreatments with ASC-CM dramatically block both 6-OHDA-induced ROS and neurotoxicity. Additionally, ASC-CM also directly attenuated H2O2-induced neuronal death. Our results suggest that ASC-CM could block 6-OHDA-induced neuronal death by inhibiting both 6-OHDA-induced ROS generation and ROS-induced neurotoxicity in neurons. Both antioxidative and neuroprotective effects of ASC-CM may be beneficial in the therapy for Parkinson's disease and other neurodegenerative diseases.

  12. Block copolymer directed synthesis of mesoporous TiO2 for dye-sensitized solar cells

    OpenAIRE

    Nedelcu, M.; Lee, J.; Crossland, E. J. W.; Warren, S.C.; Orilall, M. C.; Guldin, S.; Huettner, S.; Ducati, C.; Eder, D.; Wiesner, U.; Steiner, U.; Snaith, H. J.

    2009-01-01

    The morphology of TiO2 plays an important role in the operation of solid-state dye-sensitized solar cells. By using polyisoprene-block-ethyleneoxide (PI-b-PEO) copolymers as structure directing agents for a sol-gel based synthesis of mesoporous TiO2, we demonstrate a strategy for the detailed control of the semiconductor morphology on the 10 nm length scale. The careful adjustment of polymer molecular weight and titania precursor content is used to systematically vary the material structure a...

  13. Thermally Induced Structural Evolution and Performance of Mesoporous Block Copolymer-Directed Alumina Perovskite Solar Cells

    OpenAIRE

    Tan, Kwan Wee; Moore, David T.; Saliba, Michael; Sai, Hiroaki; Estroff, Lara A.; Hanrath, Tobias; Snaith, Henry J.; Wiesner, Ulrich

    2014-01-01

    Structure control in solution-processed hybrid perovskites is crucial to design and fabricate highly efficient solar cells. Here, we utilize in situ grazing incidence wide-angle X-ray scattering and scanning electron microscopy to investigate the structural evolution and film morphologies of methylammonium lead tri-iodide/chloride (CH3NH3PbI3–x Cl x ) in mesoporous block copolymer derived alumina superstructures during thermal annealing. We show the CH3NH3PbI3–x Cl x material evolution to be ...

  14. Inhibition of tankyrases induces Axin stabilization and blocks Wnt signalling in breast cancer cells.

    Directory of Open Access Journals (Sweden)

    Renyue Bao

    Full Text Available Constitutive Wnt signalling is characterized by excessive levels of β-catenin protein and is a frequent occurrence in cancer. APC and Axin are key components of the β-catenin destruction complex that acts to promote β-catenin degradation. The levels of Axin are in turn controlled by tankyrases, members of the PARP-family of poly-ADP-ribosylation enzymes. In colorectal cancer cells, which typically harbor APC mutations, inhibition of tankyrase activity promotes Axin stabilization and attenuates Wnt signalling. Here, we examined the effect of inhibiting tankyrases in breast cancer cells with normal APC. We show that application of the small molecule tankyrase inhibitor, XAV939 or siRNA-mediated abrogation of tankyrase expression increases Axin1 and Axin2 protein levels and attenuates Wnt-induced transcriptional responses in several breast cancer lines. In MDA-MB-231 cells, inhibiton of tankyrase activity also attenuate Wnt3a induced cell migration. Moreover, in both MDA-MB-231 and colorectal cancer cells, XAV939 inhibits cell growth under conditions of serum-deprivation. However, the presence of serum prevents this growth inhibitory effect, although inhibition of Wnt-induced transcriptional and migratory responses was maintained. These results indicate that stabilization of Axin by inhibition of tankyrases alone, may not be an effective means to block tumor cell growth and that combinatorial therapeutic approaches should be considered.

  15. RNA interference blocking the apoptosis in HEK293 cells induced by overexpression of alpha-synuclein

    Institute of Scientific and Technical Information of China (English)

    Tao Chen; Beisha Tang; Xiaoping Liao; Guoqiang Wen; Xinxiang Yan; Jifeng Guo; Yuhu Zhang; Feng Ouyang; Zhigang Long; Li Cao; Jing Li

    2009-01-01

    BACKGROUND: Overexpression of o-synuclein can induce cell apoptosis. RNA interference (RNAi)may block specific gene function and cause gene silencing.OBJECTIVE: To construct a specific and effective RNAi plasmid for the a-synuclein gene and investigate if RNAi can block apoptosis in HEK293 cells, induced by overexpression of wild-type α-synuclein.DESIGN, TIME AND SETTING: A contrast experiment based on genetically engineered cytobiology was performed at the State Key Lab of Medical Genetics of China, Xiangya Medical College of Central South University, between October 2004 and October 2008.MATERIALS: HEK293 cells and pBSHH1 plasmid were provided by the State Key Lab of Medical Genetics of China; OligDNA sequence by Sagon Bioengineering Company, Shanghai;Lipofectamine 2000 by Invitrogen, USA;α-synuclein monoclonal antibody, Hoechst 33258, and MTT by Sigma, USA; Horseradish peroxidase-coupled goat anti-rat luG by KPL, USA; FACSan flow cytometry by BD, USA.METHODS: Four target sites were used to construct hairpin RNA pBSHH1 vectors-pSYNi-1,pSYNi-2, pSYNi-3 and pSYNi-4-which were cloned in the pBSHH1 plasmid. HEK293 cells were transfected using Lipofectamine 2000. In addition, a non-transfect group and a negative plasmid transfect group were established. The cultured HEK293 cells were processed as follows:transfection of blank plasmid (blank control group), transfection of α-synuclein-pEGFP and RNAi negative vector (negative control group), and transfection of a-synuclein-pEGFP and pSYNi-1 (transfection group). Cells in all groups were transfected with Lipofectamine 2000 for 48 hours.MAIN OUTCOME MEASURES: Expression of α-synuclein mRNA and protein were detected by RT-PCR and Western blot. Cell morphology was observed under an inverted fluorescence microscope; cell viability was measured using MTT method; and cell apoptosis was determined with Annexin V-PE flow cytometry.RESULTS: a-synuclein mRNA and protein expressions were significantly decreased in the pSYNi-1

  16. Controlling potassium selectivity and proton blocking in a hybrid biological/solid-state polymer nanoporous membrane.

    Science.gov (United States)

    Balme, Sébastien; Picaud, Fabien; Kraszewski, Sebastian; Déjardin, Philippe; Janot, Jean Marc; Lepoitevin, Mathilde; Capomanes, Jhon; Ramseyer, Christophe; Henn, François

    2013-05-01

    Specific separations of protons and cations are usually performed by electromembrane processes, which require external electric energy. An easier process would be using a membrane able to separate both entities by passive diffusion. Presently, such synthetic nanoporous membranes do not exist. Here, we report the production of a robust hybrid biological/artificial solid-state membrane, which allows selective permeation of alkali metal cations without competing or concurrent permeation of protons. This membrane is simple to prepare and is based on the hydrophobic nature of the polymeric pore walls, and the confined gramicidin A molecules within. This work opens a new route for separation in the domain of nanobiofiltration, especially for tunable nanodevices based on differential ion conduction, with a fundamental understanding of the confinement mechanism.

  17. Hierarchical block structures and high-resolution model selection in large networks

    CERN Document Server

    Peixoto, Tiago P

    2013-01-01

    Discovering the large-scale topological features in empirical networks is a crucial tool in understanding how complex systems function. However most existing methods used to obtain the modular structure of networks suffer from serious problems, such as the resolution limit on the size of communities, where smaller but well-defined clusters are not detectable when the network becomes large. This phenomenon occurs for the very popular approach of modularity optimization, but also for more principled ones based on statistical inference and model selection. Here we construct a nested generative model which, through a complete description of the entire network hierarchy at multiple scales, is capable of avoiding this limitation, and enables the detection of modular structure at levels far beyond those possible by current approaches. Even with this increased resolution, the method is based on the principle of parsimony, and is capable of separating signal from noise, and thus will not lead to the identification of ...

  18. Inactivation of SAG E3 ubiquitin ligase blocks embryonic stem cell differentiation and sensitizes leukemia cells to retinoid acid.

    Directory of Open Access Journals (Sweden)

    Mingjia Tan

    Full Text Available Sensitive to Apoptosis Gene (SAG, also known as RBX2 (RING box protein-2, is the RING component of SCF (SKP1, Cullin, and F-box protein E3 ubiquitin ligase. Our previous studies have demonstrated that SAG is an anti-apoptotic protein and an attractive anti-cancer target. We also found recently that Sag knockout sensitized mouse embryonic stem cells (mES to radiation and blocked mES cells to undergo endothelial differentiation. Here, we reported that compared to wild-type mES cells, the Sag(-/- mES cells were much more sensitive to all-trans retinoic acid (RA-induced suppression of cell proliferation and survival. While wild-type mES cells underwent differentiation upon exposure to RA, Sag(-/- mES cells were induced to death via apoptosis instead. The cell fate change, reflected by cellular stiffness, can be detected as early as 12 hrs post RA exposure by AFM (Atomic Force Microscopy. We then extended this novel finding to RA differentiation therapy of leukemia, in which the resistance often develops, by testing our hypothesis that SAG inhibition would sensitize leukemia to RA. Indeed, we found a direct correlation between SAG overexpression and RA resistance in multiple leukemia lines. By using MLN4924, a small molecule inhibitor of NEDD8-Activating Enzyme (NAE, that inactivates SAG-SCF E3 ligase by blocking cullin neddylation, we were able to sensitize two otherwise resistant leukemia cell lines, HL-60 and KG-1 to RA. Mechanistically, RA sensitization by MLN4924 was mediated via enhanced apoptosis, likely through accumulation of pro-apoptotic proteins NOXA and c-JUN, two well-known substrates of SAG-SCF E3 ligase. Taken together, our study provides the proof-of-concept evidence for effective treatment of leukemia patients by RA-MLN4924 combination.

  19. Controlling potassium selectivity and proton blocking in a hybrid biological/solid-state polymer nanoporous membrane

    Science.gov (United States)

    Balme, Sébastien; Picaud, Fabien; Kraszewski, Sebastian; Déjardin, Philippe; Janot, Jean Marc; Lepoitevin, Mathilde; Capomanes, Jhon; Ramseyer, Christophe; Henn, François

    2013-04-01

    Specific separations of protons and cations are usually performed by electromembrane processes, which require external electric energy. An easier process would be using a membrane able to separate both entities by passive diffusion. Presently, such synthetic nanoporous membranes do not exist. Here, we report the production of a robust hybrid biological/artificial solid-state membrane, which allows selective permeation of alkali metal cations without competing or concurrent permeation of protons. This membrane is simple to prepare and is based on the hydrophobic nature of the polymeric pore walls, and the confined gramicidin A molecules within. This work opens a new route for separation in the domain of nanobiofiltration, especially for tunable nanodevices based on differential ion conduction, with a fundamental understanding of the confinement mechanism.Specific separations of protons and cations are usually performed by electromembrane processes, which require external electric energy. An easier process would be using a membrane able to separate both entities by passive diffusion. Presently, such synthetic nanoporous membranes do not exist. Here, we report the production of a robust hybrid biological/artificial solid-state membrane, which allows selective permeation of alkali metal cations without competing or concurrent permeation of protons. This membrane is simple to prepare and is based on the hydrophobic nature of the polymeric pore walls, and the confined gramicidin A molecules within. This work opens a new route for separation in the domain of nanobiofiltration, especially for tunable nanodevices based on differential ion conduction, with a fundamental understanding of the confinement mechanism. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr00564j

  20. Frequency Selective Surfaces with Nanoparticles Unit Cell

    Directory of Open Access Journals (Sweden)

    Nga Hung Poon

    2015-09-01

    Full Text Available The frequency selective surface (FSS is a periodic structure with filtering performance for optical and microwave signals. The general periodic arrays made with patterned metallic elements can act as an aperture or patch on a substrate. In this work, two kinds of materials were used to produce unit cells with various patterns. Gold nanoparticles of 25 nm diameter were used to form periodic monolayer arrays by a confined photocatalytic oxidation-based surface modification method. As the other material, silver gel was used to create multiple layers of silver. Due to the ultra-thin nature of the self-assembled gold nanoparticle monolayer, it is very easy to penetrate the FSS with terahertz radiation. However, the isolated silver islands made from silver gel form thicker multiple layers and contribute to much higher reflectance. This work demonstrated that multiple silver layers are more suitable than gold nanoparticles for use in the fabrication of FSS structures.

  1. Quiescent S-phase cells, G1-Block and Ρ53 status in four human tumor cell lines

    International Nuclear Information System (INIS)

    Quiescent S-phase cells, i.e. cells with an S-phase DNA content that do not take up BrdU, have earlier been observed in a human melanoma cell line (MeWo) a few days after irradiation and/or hyperthermia. In order to see whether this phenomenon was cell line dependent, similar experiments were carried out with another melanoma (Be11) as well as with two squamous cell carcinomas (4451, 4197). These four cell lines differed with respect to their p53 gene (MeWo, 4451). They were also studied with respect to cell cycle changes during the first day after treatment. Cells unable to undergo a Gl-block may have less time available for repair of DNA damage before entering the S-phase. We suggest that this causes during DNA replication to a cessation of cell cycle progression and eventually to some kind of interphase death. Apoptosis does not seem to be involved here as it should affect the wild types rather than the mutants. It has been shown by others that loss of p53 wild-type function leads to an increase in gene amplification as well as to an increase in UV-induced and spontaneous mutations. The occurrence of quiescent S-phase cells may be yet another indicator of this genomic instability. (authors)

  2. UTILITY OF CELL BLOCK TECHNIQUE BY MICROWAVE PROCESSING FOR RAPID DIAGNOSIS IN FLUIDS AND FINE NEEDLE ASPIRATES

    Directory of Open Access Journals (Sweden)

    Shailaja

    2014-11-01

    Full Text Available : INTRODUCTION: The present study was carried out to evaluate the cell block technique prepared out of the residue of fluids and fine needle aspirate (FNA samples after routine cytological processing. In addition it was processed in a microwave to facilitate early reporting. Aims and OBJECTIVES: The aim of the present study was to correlate the cytological findings with those of cell block sections and to establish the microwave processing technique in preparation of paraffin blocks. MATERIALS AND METHODS: A total of 100 samples were studied over a two year period. They comprised of 64 fluids and 36 FNA samples. In 88 cases, both cytology and histology were available for correlation. For cell block preparation, the modified plasma-thrombin technique and for microwave processing, the modified Bellotti’s technique were used respectively. RESULTS: Positive correlation between cell block and cytology for malignant and benign lesions in fluid specimens was seen in 21.87% and 51.56% cases respectively. Positive correlation between cell block and cytology for malignant and benign lesions in FNA specimens was seen in 47.22% and 33.33% cases respectively. The sensitivity and specificity of cell blocks and cytology smears were calculated. Also the use of microwave processing allowed us to give report on the same day without affecting the quality of sections and staining. CONCLUSIONS: The present study indicates that even after cytological processing of fluids and FNA specimens, some residue is left behind which may contain valuable diagnostic material which can be processed further as a cell block. In addition, microwave processing gives the added benefit of rapid reports without compromise in the quality of reports.

  3. Selectively improving nikkomycin Z production by blocking the imidazolone biosynthetic pathway of nikkomycin X and uracil feeding in Streptomyces ansochromogenes

    Directory of Open Access Journals (Sweden)

    Yang Haihua

    2009-11-01

    Full Text Available Abstract Background Nikkomycins are a group of peptidyl nucleoside antibiotics and act as potent inhibitors of chitin synthases in fungi and insects. Nikkomycin X and Z are the main components produced by Streptomyces ansochromogenes. Of them, nikkomycin Z is a promising antifungal agent with clinical significance. Since highly structural similarities between nikkomycin Z and X, separation of nikkomycin Z from the culture medium of S. ansochromogenes is difficult. Thus, generating a nikkomycin Z selectively producing strain is vital to scale up the nikkomycin Z yields for clinical trials. Results A nikkomycin Z producing strain (sanPDM was constructed by blocking the imidazolone biosynthetic pathway of nikkomycin X via genetic manipulation and yielded 300 mg/L nikkomycin Z and abolished the nikkomycin X production. To further increase the yield of nikkomycin Z, the effects of different precursors on its production were investigated. Precursors of nucleoside moiety (uracil or uridine had a stimulatory effect on nikkomycin Z production while precursors of peptidyl moiety (L-lysine and L-glutamate had no effect. sanPDM produced the maximum yields of nikkomycin Z (800 mg/L in the presence of uracil at the concentration of 2 g/L and it was approximately 2.6-fold higher than that of the parent strain. Conclusion A high nikkomycin Z selectively producing was obtained by genetic manipulation combined with precursors feeding. The strategy presented here might be applicable in other bacteria to selectively produce targeted antibiotics.

  4. Cardiac atrioventricular conduction improved by autologous transplantation of mesenchymal stem cells in canine atrioventricular block models

    Institute of Scientific and Technical Information of China (English)

    Xiaoqing Ren; Jielin Pu; Shu Zhang; Liang Meng; Fangzheng Wang

    2007-01-01

    Objective Atrioventricular block (AVB) is a common and serious arrhythmia. At present, there is no perfect method of treatment for this kind of arrhythmia. The purpose of this study was to regenerate cardiac atrioventricular conduction by autologous transplantation of bone marrow mesenchymal stem cells (MSCs), and explore new methods for therapy of atrioventricular block. Methods Eleven Mongrel canines were randomized to MSCs transplantation (n=6) or control (n=5) group. The models of permanent and complete AVB in 11 canines were established by ablating His bundle with radiofrequency technique. At 4 weeks after AVB, bone marrow was aspirated from the iliac crest. MSCs were isolated and culture-expanded by means of gradient centrifugal and adherence to growth technique, and differentiated by 5-azacytidine in vitro. Differentiated MSCs (1ml, 1.5×107cells) labeled with BrdU were autotransplanted into His bundle area of canines by direct injection in the experimental group, and 1ml DMEM in the control group. At 1-12 weeks after operation,the effects of autologous MSCs transplantation on AVB models were evaluated by electrocardiogram, pathologic and immunohistochemical staining technique. Results Compared with the control group, there was a distinct improvement in atrioventricular conduction function in the experimental group. MSCs transplanted in His bundle were differentiated into analogous conduction system cells and endothelial cells in vivo, and established gap junction with host cardiomyocytes. Conclusions The committed-induced MSCs transplanted into His bundle area could differentiate into analogous conduction system cells and improve His conduction function in canine AVB models.

  5. Podophyllotoxin acetate blocks IR-induced invasion of non-small cell lung cancer cell, A549

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Jeong Hyun; Choi, Jae Yeon; Hwang, Sang-Gu; Um, Hong-Duck; Park, Jong Kuk [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)

    2015-05-15

    Some research result presented that local radiotherapy administered to primary tumors speeds their metastatic growth in vivo (4-6), thereby suggesting that besides its therapeutic effects, IR promotes the malignant behaviors of surviving cancer cells. Our findings demonstrate podophyllotoxin acetate (PA), one of new natural products, prevented side effects of IR such as invasion or metastasis promotion for improve the efficacy of radiotherapy. In this study, we demonstrated that PA inhibits IR-induced invasion and migration of A549 cells. We also observed that IR stimulates several intracellular pathway involving EMT and MAPKinses; EMT-associated events including an increase of vimentin levels and increased phosphorylation of p38 ERK, JNK in A549 cells. PA could decrease these activations of several intracellular signaling molecules. Therefore, PA might inhibit IRinduced invasion and migration via blocking EMT and MAPKiase pathway of A549 cells.

  6. The effect of blocking angiogenesis on anterior cruciate ligament healing following stem cell transplantation.

    Science.gov (United States)

    Takayama, Koji; Kawakami, Yohei; Mifune, Yutaka; Matsumoto, Tomoyuki; Tang, Ying; Cummins, James H; Greco, Nick; Kuroda, Ryosuke; Kurosaka, Masahiro; Wang, Bing; Fu, Freddie H; Huard, Johnny

    2015-08-01

    Ruptured human anterior cruciate ligaments (ACL) contain vascular stem cells capable of enhancing the healing of tendon grafts. In the current study we explored the role that neo-angiogenesis plays in ACL healing. ACL-derived CD34+ cells were isolated via Fluorescence Activated Cell Sorting (FACS) from the rupture sites of human ACLs. The cells were then virally transduced to express either vascular endothelial growth factor (VEGF) or soluble FLT-1 (sFLT-1), which is an antagonist of VEGF. We established five groups: CD34+VEGF(100%), where 100% of the cells were transduced with VEGF, CD34+VEGF(25%), where only 25% of the cells were transduced with VEGF, CD34+, CD34+sFLT-1, and a No cells group. The CD34+sFLT1 group had a significant reduction in biomechanical strength compared to the CD34+ group at 4 and 8 weeks; whereas the biomechanical strength of the CD34+VEGF(25%) group was significantly greater than the CD34+ group at week 4; however, no difference was observed by week 8. Immunohistochemical staining demonstrated a significantly lower number of isolectin B4 and hCD31 positive cells, markers associated with angiogenesis, in the CD34+sFLT1 group, and a higher number of isolectin B4 and hCD31 positive cells in the CD34+VEGF(100%) and CD34+VEGF(25%) groups compared to the CD34+ group. Graft maturation was significantly delayed in the CD34+sFLT1 group and accelerated in the CD34+VEGF(25%) group compared to the CD34+ group. In conclusion, blocking VEGF reduced angiogenesis, graft maturation and biomechanical strength following ACL reconstruction. Native expression of VEGF by the CD34+ cells improved tendon graft maturation and biomechanical strength; however, over-expression of VEGF impeded improvements in biomechanical strength.

  7. B cell-specific S1PR1 deficiency blocks prion dissemination between secondary lymphoid organs.

    Science.gov (United States)

    Mok, Simon W F; Proia, Richard L; Brinkmann, Volker; Mabbott, Neil A

    2012-05-15

    Many prion diseases are peripherally acquired (e.g., orally or via lesions to skin or mucous membranes). After peripheral exposure, prions replicate first upon follicular dendritic cells (FDC) in the draining lymphoid tissue before infecting the brain. However, after replication upon FDC within the draining lymphoid tissue, prions are subsequently propagated to most nondraining secondary lymphoid organs (SLO), including the spleen, by a previously underdetermined mechanism. The germinal centers in which FDC are situated produce a population of B cells that can recirculate between SLO. Therefore, we reasoned that B cells were ideal candidates by which prion dissemination between SLO may occur. Sphingosine 1-phosphate receptor (S1PR)1 stimulation controls the egress of T and B cells from SLO. S1PR1 signaling blockade sequesters lymphocytes within SLO, resulting in lymphopenia in the blood and lymph. We show that, in mice treated with the S1PR modulator FTY720 or with S1PR1 deficiency restricted to B cells, the dissemination of prions from the draining lymph node to nondraining SLO is blocked. These data suggest that B cells interacting with and acquiring surface proteins from FDC and recirculating between SLO via the blood and lymph mediate the initial propagation of prions from the draining lymphoid tissue to peripheral tissues. PMID:22504650

  8. Isolation of a mutant MDBK cell line resistant to bovine viral diarrhea virus infection due to a block in viral entry.

    Science.gov (United States)

    Flores, E F; Donis, R O

    1995-04-20

    A cell line, termed CRIB, resistant to infection with bovine viral diarrhea virus (BVDV) has been derived from the MDBK bovine kidney cell line. CRIB cells were obtained by selection and cloning of cells surviving infection with a highly cytolytic BVDV strain. CRIB cells contain no detectable infectious or defective BVDV as ascertained by cocultivation, animal inoculation, indirect immunofluorescence, Western immunoblot, Northern hybridization, and RNA PCR. Inoculation of CRIB cells with 24 cytopathic and noncytopathic BVDV strains does not result in expression of viral genes or amplification of input virus. Karyotype and isoenzyme analyses demonstrated that CRIB are genuine bovine cells. CRIB cells are as susceptible as the parental MDBK cells to 10 other bovine viruses, indicating that these cells do not have a broad defect blocking viral replication. Transfection of CRIB cells with BVDV RNA or virus inoculation in the presence of polyethylene-glycol results in productive infection, indicating that the defect of CRIB cells is at the level of virus entry. CRIB cells are the first bovine cells reported to be resistant to BVDV infection in vitro and may be a useful tool for studying the early interactions of pestiviruses with host cells.

  9. Orally active vasopressin V1a receptor antagonist, SRX251, selectively blocks aggressive behavior.

    Science.gov (United States)

    Ferris, Craig F; Lu, Shi-Fang; Messenger, Tara; Guillon, Christophe D; Heindel, Ned; Miller, Marvin; Koppel, Gary; Robert Bruns, F; Simon, Neal G

    2006-02-01

    Arginine vasopressin functions as a neurochemical signal in the brain to affect social behavior. There is an expanding literature from animal and human studies showing that vasopressin, through the vasopressin 1A receptor (V1A), can stimulate aggressive behavior. Using a novel monocylic beta lactam platform, a series of orally active vasopressin V1a antagonists was developed with high affinity for the human receptor. SRX251 was chosen from this series of V1a antagonists to screen for effects on serenic activity in a resident-intruder model of offensive aggression. Resident, male Syrian golden hamsters were given oral doses of SRX251 or intraperitoneal Manning compound, a selective V1a receptor antagonist with reduced brain penetrance, at doses of 0.2 microg, 20 microg, 2 mg/kg or vehicle. When tested 90-120 min later, SRX251, but not Manning compound, caused a significant dose-dependent reduction in offensive aggression toward intruders as measured by latency to bite and number of bites. The reduction in aggression persisted for over 6 h and was no longer present 12 h post treatment. SRX251 did not alter the amount of time the resident investigated the intruder, olfactory communication, general motor activity, or sexual motivation. These data corroborate previous studies showing a role for vasopressin neurotransmission in aggression and suggest that V1a receptor antagonists may be used to treat interpersonal violence co-occurring with such illness as ADHD, autism, bipolar disorder, and substance abuse. PMID:16504276

  10. Poly[(3-hexylthiophene-block-(3-semifluoroalkylthiophene] for Polymer Solar Cells

    Directory of Open Access Journals (Sweden)

    Takeshi Toru

    2010-12-01

    Full Text Available We report the synthesis of poly[(3-hexylthiophene-block-(3-(4,4,5,5,6,6,7,7,7-nonafluoroheptylthiophene], P(3HT-b-3SFT, carried out by the Grignard Metathesis Method (GRIM. The copolymers composition was determined by 1H and 19F NMR spectroscopies, and gel permeation chromatography (GPC. The thin films of P(3HT‑b‑3SFT were investigated by ultraviolet-visible absorption spectroscopy and atomic force microscopy (AFM. We also fabricated bulk-hetero junction (BHJ solar cells based on blends of P(3HT-b-3SFT and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM. Although the composition ratio of P3SFT in P(3HT-b-3SFT was low, the influence of P3SFT on the morphology and properties of solar cells was significant. The annealing process for the BHJ solar cells induced the formation of large domains and led to poor solar cell performance. The BHJ solar cells, based on PCBM and P(3HT-b-3SFT, prepared by the non-annealing process, had a maximum power conversion efficiency of 0.84% under 100 mW/cm2 (AM 1.5 solar illumination in air.

  11. Amygdalin Blocks Bladder Cancer Cell Growth In Vitro by Diminishing Cyclin A and cdk2

    Science.gov (United States)

    Makarević, Jasmina; Rutz, Jochen; Juengel, Eva; Kaulfuss, Silke; Reiter, Michael; Tsaur, Igor; Bartsch, Georg; Haferkamp, Axel; Blaheta, Roman A.

    2014-01-01

    Amygdalin, a natural compound, has been used by many cancer patients as an alternative approach to treat their illness. However, whether or not this substance truly exerts an anti-tumor effect has never been settled. An in vitro study was initiated to investigate the influence of amygdalin (1.25–10 mg/ml) on the growth of a panel of bladder cancer cell lines (UMUC-3, RT112 and TCCSUP). Tumor growth, proliferation, clonal growth and cell cycle progression were investigated. The cell cycle regulating proteins cdk1, cdk2, cdk4, cyclin A, cyclin B, cyclin D1, p19, p27 as well as the mammalian target of rapamycin (mTOR) related signals phosphoAkt, phosphoRaptor and phosphoRictor were examined. Amygdalin dose-dependently reduced growth and proliferation in all three bladder cancer cell lines, reflected in a significant delay in cell cycle progression and G0/G1 arrest. Molecular evaluation revealed diminished phosphoAkt, phosphoRictor and loss of Cdk and cyclin components. Since the most outstanding effects of amygdalin were observed on the cdk2-cyclin A axis, siRNA knock down studies were carried out, revealing a positive correlation between cdk2/cyclin A expression level and tumor growth. Amygdalin, therefore, may block tumor growth by down-modulating cdk2 and cyclin A. In vivo investigation must follow to assess amygdalin's practical value as an anti-tumor drug. PMID:25136960

  12. Amygdalin blocks bladder cancer cell growth in vitro by diminishing cyclin A and cdk2.

    Directory of Open Access Journals (Sweden)

    Jasmina Makarević

    Full Text Available Amygdalin, a natural compound, has been used by many cancer patients as an alternative approach to treat their illness. However, whether or not this substance truly exerts an anti-tumor effect has never been settled. An in vitro study was initiated to investigate the influence of amygdalin (1.25-10 mg/ml on the growth of a panel of bladder cancer cell lines (UMUC-3, RT112 and TCCSUP. Tumor growth, proliferation, clonal growth and cell cycle progression were investigated. The cell cycle regulating proteins cdk1, cdk2, cdk4, cyclin A, cyclin B, cyclin D1, p19, p27 as well as the mammalian target of rapamycin (mTOR related signals phosphoAkt, phosphoRaptor and phosphoRictor were examined. Amygdalin dose-dependently reduced growth and proliferation in all three bladder cancer cell lines, reflected in a significant delay in cell cycle progression and G0/G1 arrest. Molecular evaluation revealed diminished phosphoAkt, phosphoRictor and loss of Cdk and cyclin components. Since the most outstanding effects of amygdalin were observed on the cdk2-cyclin A axis, siRNA knock down studies were carried out, revealing a positive correlation between cdk2/cyclin A expression level and tumor growth. Amygdalin, therefore, may block tumor growth by down-modulating cdk2 and cyclin A. In vivo investigation must follow to assess amygdalin's practical value as an anti-tumor drug.

  13. Perivagal antagonist treatment in rats selectively blocks the reflex and afferent responses of vagal lung C fibers to intravenous agonists.

    Science.gov (United States)

    Lin, Yu-Jung; Lin, You Shuei; Lai, Ching Jung; Yuan, Zung Fan; Ruan, Ting; Kou, Yu Ru

    2013-02-01

    The terminals of vagal lung C fibers (VLCFs) express various types of pharmacological receptors that are important to the elicitation of airway reflexes and the development of airway hypersensitivity. We investigated the blockade of the reflex and afferent responses of VLCFs to intravenous injections of agonists using perivagal treatment with antagonists (PAT) targeting the transient receptor potential vanilloid 1, P2X, and 5-HT(3) receptors in anesthetized rats. Blockading these responses via perivagal capsaicin treatment (PCT), which blocks the neural conduction of C fibers, was also studied. We used capsaicin, α,β-methylene-ATP, and phenylbiguanide as the agonists, and capsazepine, iso-pyridoxalphosphate-6-azophenyl-2',5'-disulfonate, and tropisetron as the antagonists of transient receptor potential vanilloid 1, P2X, and 5-HT(3) receptors, respectively. We found that each of the PATs abolished the VLCF-mediated reflex apnea evoked by the corresponding agonist, while having no effect on the response to other agonists. Perivagal vehicle treatment failed to produce any such blockade. These blockades had partially recovered at 3 h after removal of the PATs. In contrast, PCT abolished the reflex apneic response to all three agonists. Both PATs and PCT did not affect the myelinated afferent-mediated apneic response to lung inflation. Consistently, our electrophysiological studies revealed that each of the PATs prevented the VLCF responses to the corresponding agonist, but not to any other agonist. PCT inevitably prevented the VLCF responses to all three agonists. Thus these PATs selectively blocked the stimulatory action of corresponding agonists on the VLCF terminals via mechanisms that are distinct from those of PCT. PAT may become a novel intervention for studying the pharmacological modulation of VLCFs.

  14. FHR3 Blocks C3d-Mediated Coactivation of Human B Cells.

    Science.gov (United States)

    Buhlmann, Denise; Eberhardt, Hannes U; Medyukhina, Anna; Prodinger, Wolfgang M; Figge, Marc Thilo; Zipfel, Peter F; Skerka, Christine

    2016-07-15

    The autoimmune renal disease deficient for complement factor H-related (CFHR) genes and autoantibody-positive form of hemolytic uremic syndrome is characterized by the presence of autoantibodies specific for the central complement regulator, factor H, combined with a homozygous deficiency, mostly in CFHR3 and CFHR1 Because FHR3 and FHR1 bind to C3d and inactivated C3b, which are ligands for complement receptor type 2 (CR2/CD21), the aim of the current study was to examine whether FHR3-C3d or FHR1-C3d complexes modulate B cell activation. Laser-scanning microscopy and automated image-based analysis showed that FHR3, but not FHR1 or factor H, blocked B cell activation by the BCR coreceptor complex (CD19/CD21/CD81). FHR3 bound to C3d, thereby inhibiting the interaction between C3d and CD21 and preventing colocalization of the coreceptor complex with the BCR. FHR3 neutralized the adjuvant effect of C3d on B cells, as shown by inhibited intracellular CD19 and Akt phosphorylation in Raji cells, as well as Ca(2+) release in peripheral B cells. In cases of CFHR3/CFHR1 deficiency, the FHR3 binding sites on C3d are occupied by factor H, which lacks B cell-inhibitory functions. These data provide evidence that FHR3, which is absent in patients with the autoimmune form of hemolytic uremic syndrome, is involved in B cell regulation. PMID:27279373

  15. The QKI-6 and QKI-7 RNA binding proteins block proliferation and promote Schwann cell myelination.

    Directory of Open Access Journals (Sweden)

    Daniel Larocque

    Full Text Available BACKGROUND: The quaking viable (qk(v mice have uncompacted myelin in their central and peripheral nervous system (CNS, PNS. The qk gene encodes 3 major alternatively spliced isoforms that contain unique sequence at their C-terminus dictating their cellular localization. QKI-5 is a nuclear isoform, whereas QKI-6 and QKI-7 are cytoplasmic isoforms. The qk(v mice harbor an enhancer/promoter deletion that prevents the expression of isoforms QKI-6 and QKI-7 in myelinating cells resulting in a dysmyelination phenotype. It was shown that QKI regulates the differentiation of oligodendrocytes, the myelinating cells of the CNS, however, little is known about the role of the QKI proteins, or RNA binding proteins in PNS myelination. METHODOLOGY/PRINCIPAL FINDINGS: To define the role of the QKI proteins in PNS myelination, we ectopically expressed QKI-6 and QKI-7 in primary rat Schwann cell/neuron from dorsal root ganglia cocultures. We show that the QKI isoforms blocked proliferation and promoted Schwann cell differentiation and myelination. In addition, these events were coordinated with elevated proteins levels of p27(KIP1 and myelin basic protein (MBP, markers of Schwann cell differentiation. QKI-6 and QKI-7 expressing co-cultures contained myelinated fibers that had directionality and contained significantly thicker myelin, as assessed by electron microscopy. Moreover, QKI-deficient Schwann cells had reduced levels of MBP, p27(KIP1 and Krox-20 mRNAs, as assessed by quantitative RT-PCR. CONCLUSIONS/SIGNIFICANCE: Our findings suggest that the QKI-6 and QKI-7 RNA binding proteins are positive regulators of PNS myelination and show that the QKI RNA binding proteins play a key role in Schwann cell differentiation and myelination.

  16. Inhibitors of the cytochrome P-450 enzymes block the secretagogue-induced release of corticotropin in mouse pituitary tumor cells.

    OpenAIRE

    Luini, A G; Axelrod, J

    1985-01-01

    A mouse pituitary tumor cell line (AtT-20) releases corticotropin (ACTH) in response to a number of secretagogues, including corticotropin-releasing factor (CRF), beta-adrenergic agents, N6,O2'-dibutyryladenosine 3',5'-cyclic monophosphate (Bt2 cAMP), and potassium. The stimulation of ACTH secretion induced by the secretagogues can be blocked by inhibitors of the enzymes that generate (phospholipase A2) and metabolize (lipoxygenase and epoxygenase) arachidonic acid. The phospholipase A2 block...

  17. Dectin-1 agonist selectively induces IgG1 class switching by LPS-activated mouse B cells.

    Science.gov (United States)

    Seo, Beom-Seok; Park, Ha-Yan; Yoon, Hee-Kyung; Yoo, Yung-Choon; Lee, Junglim; Park, Seok-Rae

    2016-10-01

    Heat-killed Saccharomyces cerevisiae (HKSC) is an agonist for Dectin-1, a major fungal cell wall β-glucan receptor. We previously reported that HKSC selectively enhances IgG1 production by LPS-activated mouse B cells. To determine if this IgG1 selectivity is caused by selective IgG1 class switching, we performed RT-PCRs for measuring germline transcripts (GLTs), flow cytometric analyses for detecting Ig-expressing cells, and ELISPOT assays for measuring the number of Ig-secreting cells in HKSC/LPS-stimulated mouse B cell cultures. HKSC selectively enhanced expression of GLTγ1, the number of IgG1-expressing cells, and the number of IgG1-secreting B cells in the presence of LPS stimulation. In addition, HKSC induced the expression of CD69, an activation marker for B lymphocytes, and the expression of surface Dectin-1. Two Dectin-1 antagonists, laminarin and a neutralizing Dectin-1 antibody, selectively diminished HKSC-reinforced IgG1 production by LPS-stimulated B cells. Furthermore, depleted zymosan (dzn), a Dectin-1 agonist with increased selectivity, also selectively enhanced GLTγ1 transcription. The Dectin-1 antagonists blocked dzn-induced IgG1 production by LPS-activated B cells. Collectively, these results suggest that Dectin-1 agonists selectively induce IgG1 class switching by direct stimulation of Dectin-1 on LPS-activated B cells resulting in selective production of IgG1.

  18. Combining cluster analysis, feature selection and multiple support vector machine models for the identification of human ether-a-go-go related gene channel blocking compounds.

    Science.gov (United States)

    Nisius, Britta; Göller, Andreas H; Bajorath, Jürgen

    2009-01-01

    Blockade of the human ether-a-go-go related gene potassium channel is regarded as a major cause of drug toxicity and associated with severe cardiac side-effects. A variety of in silico models have been reported to aid in the identification of compounds blocking the human ether-a-go-go related gene channel. Herein, we present a classification approach for the detection of diverse human ether-a-go-go related gene blockers that combines cluster analysis of training data, feature selection and support vector machine learning. Compound learning sets are first divided into clusters of similar molecules. For each cluster, independent support vector machine models are generated utilizing preselected MACCS structural keys as descriptors. These models are combined to predict human ether-a-go-go related gene inhibition of our large compound data set with consistent experimental measurements (i.e. only patch clamp measurements on mammalian cell lines). Our combined support vector machine model achieves a prediction accuracy of 85% on this data set and performs better than alternative methods used for comparison. We also find that structural keys selected on the basis of statistical criteria are associated with molecular substructures implicated in human ether-a-go-go related gene channel binding.

  19. Surfactant-free CZTS nanoparticles as building blocks for low-cost solar cell absorbers

    Science.gov (United States)

    Zaberca, O.; Oftinger, F.; Chane-Ching, J. Y.; Datas, L.; Lafond, A.; Puech, P.; Balocchi, A.; Lagarde, D.; Marie, X.

    2012-05-01

    A process route for the fabrication of solvent-redispersible, surfactant-free Cu2ZnSnS4 (CZTS) nanoparticles has been designed with the objective to have the benefit of a simple sulfide source which advantageously acts as (i) a complexing agent inhibiting crystallite growth, (ii) a surface additive providing redispersion in low ionic strength polar solvents and (iii) a transient ligand easily replaced by an carbon-free surface additive. This multifunctional use of the sulfide source has been achieved through a fine tuning of ((Cu2+)a(Zn2+)b(Sn4+)c(Tu)d(OH-)e)t+, Tu = thiourea) oligomers, leading after temperature polycondensation and S2- exchange to highly concentrated (c > 100 g l-1), stable, ethanolic CZTS dispersions. The good electronic properties and low-defect concentration of the sintered, crack-free CZTSe films resulting from these building blocks was shown by photoluminescence investigation, making these building blocks interesting for low-cost, high-performance CZTSe solar cells.

  20. Surfactant-free CZTS nanoparticles as building blocks for low-cost solar cell absorbers.

    Science.gov (United States)

    Zaberca, O; Oftinger, F; Chane-Ching, J Y; Datas, L; Lafond, A; Puech, P; Balocchi, A; Lagarde, D; Marie, X

    2012-05-11

    A process route for the fabrication of solvent-redispersible, surfactant-free Cu₂ZnSnS₄ (CZTS) nanoparticles has been designed with the objective to have the benefit of a simple sulfide source which advantageously acts as (i) a complexing agent inhibiting crystallite growth, (ii) a surface additive providing redispersion in low ionic strength polar solvents and (iii) a transient ligand easily replaced by an carbon-free surface additive. This multifunctional use of the sulfide source has been achieved through a fine tuning of ((Cu²⁺)(a)(Zn²⁺)(b)(Sn⁴⁺)(c)(Tu)(d)(OH⁻)(e))(t⁺), Tu = thiourea) oligomers, leading after temperature polycondensation and S²⁻ exchange to highly concentrated (c > 100 g l⁻¹), stable, ethanolic CZTS dispersions. The good electronic properties and low-defect concentration of the sintered, crack-free CZTSe films resulting from these building blocks was shown by photoluminescence investigation, making these building blocks interesting for low-cost, high-performance CZTSe solar cells. PMID:22513652

  1. ING1 and 5-Azacytidine Act Synergistically to Block Breast Cancer Cell Growth

    Science.gov (United States)

    Thakur, Satbir; Feng, Xiaolan; Qiao Shi, Zhong; Ganapathy, Amudha; Kumar Mishra, Manoj; Atadja, Peter; Morris, Don; Riabowol, Karl

    2012-01-01

    Background Inhibitor of Growth (ING) proteins are epigenetic “readers” that recognize trimethylated lysine 4 of histone H3 (H3K4Me3) and target histone acetyl transferase (HAT) and histone deacetylase (HDAC) complexes to chromatin. Methods and Principal Findings Here we asked whether dysregulating two epigenetic pathways with chemical inhibitors showed synergistic effects on breast cancer cell line killing. We also tested whether ING1 could synergize better with chemotherapeutics that target the same epigenetic mechanism such as the HDAC inhibitor LBH589 (Panobinostat) or a different epigenetic mechanism such as 5-azacytidine (5azaC), which inhibits DNA methyl transferases. Simultaneous treatment of breast cancer cell lines with LBH589 and 5azaC did not show significant synergy in killing cells. However, combination treatment of ING1 with either LBH589 or 5azaC did show synergy. The combination of ING1b with 5azaC, which targets two distinct epigenetic mechanisms, was more effective at lower doses and enhanced apoptosis as determined by Annexin V staining and cleavage of caspase 3 and poly-ADP-ribose polymerase (PARP). ING1b plus 5azaC also acted synergistically to increase γH2AX staining indicating significant levels of DNA damage were induced. Adenoviral delivery of ING1b with 5azaC also inhibited cancer cell growth in a murine xenograft model and led to tumor regression when viral concentration was optimized in vivo. Conclusions These data show that targeting distinct epigenetic pathways can be more effective in blocking cancer cell line growth than targeting the same pathway with multiple agents, and that using viral delivery of epigenetic regulators can be more effective in synergizing with a chemical agent than using two chemotherapeutic agents. This study also indicates that the ING1 epigenetic regulator may have additional activities in the cell when expressed at high levels. PMID:22916295

  2. ING1 and 5-azacytidine act synergistically to block breast cancer cell growth.

    Directory of Open Access Journals (Sweden)

    Satbir Thakur

    Full Text Available BACKGROUND: Inhibitor of Growth (ING proteins are epigenetic "readers" that recognize trimethylated lysine 4 of histone H3 (H3K4Me3 and target histone acetyl transferase (HAT and histone deacetylase (HDAC complexes to chromatin. METHODS AND PRINCIPAL FINDINGS: Here we asked whether dysregulating two epigenetic pathways with chemical inhibitors showed synergistic effects on breast cancer cell line killing. We also tested whether ING1 could synergize better with chemotherapeutics that target the same epigenetic mechanism such as the HDAC inhibitor LBH589 (Panobinostat or a different epigenetic mechanism such as 5-azacytidine (5azaC, which inhibits DNA methyl transferases. Simultaneous treatment of breast cancer cell lines with LBH589 and 5azaC did not show significant synergy in killing cells. However, combination treatment of ING1 with either LBH589 or 5azaC did show synergy. The combination of ING1b with 5azaC, which targets two distinct epigenetic mechanisms, was more effective at lower doses and enhanced apoptosis as determined by Annexin V staining and cleavage of caspase 3 and poly-ADP-ribose polymerase (PARP. ING1b plus 5azaC also acted synergistically to increase γH2AX staining indicating significant levels of DNA damage were induced. Adenoviral delivery of ING1b with 5azaC also inhibited cancer cell growth in a murine xenograft model and led to tumor regression when viral concentration was optimized in vivo. CONCLUSIONS: These data show that targeting distinct epigenetic pathways can be more effective in blocking cancer cell line growth than targeting the same pathway with multiple agents, and that using viral delivery of epigenetic regulators can be more effective in synergizing with a chemical agent than using two chemotherapeutic agents. This study also indicates that the ING1 epigenetic regulator may have additional activities in the cell when expressed at high levels.

  3. Electrodeposited Ultrathin TiO2 Blocking Layers for Efficient Perovskite Solar Cells

    Science.gov (United States)

    Su, Tzu-Sen; Hsieh, Tsung-Yu; Hong, Cheng-You; Wei, Tzu-Chien

    2015-11-01

    In this study, the electrodeposition (ED) of ultrathin, compact TiO2 blocking layers (BLs) on fluorine-doped tin oxide (FTO) glass for perovskite solar cells (PSCs) is evaluated. This bottom-up method allows for controlling the morphology and thickness of TiO2 films by simply manipulating deposition conditions. Compared with BLs produced using the spin-coating (SC) method, BLs produced using ED exhibit satisfactory surface coverage, even with a film thickness of 29 nm. Evidence from cyclic voltammetry shows that an ED BL suppresses interfacial recombination more profoundly than an SC BL does, consequently improving the photovoltaic properties of the PSC significantly. A PSC equipped with an ED TiO2 BL having a 13.6% power conversion efficiency is demonstrated.

  4. S100A4 silencing blocks invasive ability of esophageal squamous cell carcinoma cells

    Institute of Scientific and Technical Information of China (English)

    Dong Chen; Xue-Feng Zheng; Ze-You Yang; Dong-Xiao Liu; Guo-You Zhang; Xue-Long Jiao; Hui Zhao

    2012-01-01

    AIM:To investigate a potential role of S100A4 in esophagus squamous cell carcinoma metastasis (ESCCs).METHODS:Expression of S100A4 and E-cadherin were analyzed in frozen sections from ESCCs (metastasis,n =28; non-metastasis,n =20) by reverse transcription-polymerase chain reaction,quantitative polymerase chain reaction and immunohistochemistry.To explore the influence of S100A4 on esophageal cancer invasion and metastasis,S100A4 was overexpressed or silenced by S100A4 siRNA in TE-13 or Eca-109 cells in vitro and in vivo.RESULTS:We found the mRNA and protein levels of S100A4 expression in ESCCs was significantly upregulated,and more importantly,that expression of S100A4 and E cadherin are strongly negatively correlated in patients who had metastasis.It was indicated that overexpression of S100A4 in TE-13 and Eca-109 cells downregulates the expression of E-cadherin,leading to increased cell migration in vitro,whereas knockdown of S100A4 inhibited cell migration and upregulation of E-cadherin expression.Moreover,the loss of cell metastatic potential was rescued by overexpression of E-cadherin completely.In addition,nude mice inoculated with S100A4 siRNA-transfected cells exhibited a significantly decreased invasion ability in vivo.CONCLUSION:S100A4 may be involved in ESCC progression by regulate E-cadherin expression,vectorbased RNA interference targeting S100A4 is a potential therapeutic method for human ESCC.

  5. Inhibition of apoptosis blocks human motor neuron cell death in a stem cell model of spinal muscular atrophy.

    Directory of Open Access Journals (Sweden)

    Dhruv Sareen

    Full Text Available Spinal muscular atrophy (SMA is a genetic disorder caused by a deletion of the survival motor neuron 1 gene leading to motor neuron loss, muscle atrophy, paralysis, and death. We show here that induced pluripotent stem cell (iPSC lines generated from two Type I SMA subjects-one produced with lentiviral constructs and the second using a virus-free plasmid-based approach-recapitulate the disease phenotype and generate significantly fewer motor neurons at later developmental time periods in culture compared to two separate control subject iPSC lines. During motor neuron development, both SMA lines showed an increase in Fas ligand-mediated apoptosis and increased caspase-8 and-3 activation. Importantly, this could be mitigated by addition of either a Fas blocking antibody or a caspase-3 inhibitor. Together, these data further validate this human stem cell model of SMA, suggesting that specific inhibitors of apoptotic pathways may be beneficial for patients.

  6. Treatment outcomes of intradiscal steroid injection/selective nerve root block for 161 patients with cervical radiculopathy.

    Science.gov (United States)

    Ito, Keigo; Yukawa, Yasutsugu; Machino, Masaaki; Inoue, Taro; Ouchida, Jun; Tomita, Keisuke; Kato, Fumihiko

    2015-02-01

    Patients with cervical radiculopathy (CR) were treated with intradiscal injection of steroids (IDIS) and/or selective nerve root block (SNRB) at our hospital. We retrospectively report the outcomes of these nonsurgical treatments for CR. 161 patients who were followed up for >2months were enrolled in this study. Patients' clinical manifestations were classified as arm pain, arm numbness, neck and/or scapular pain, and arm paralysis. Improvement in each manifestation was classified as "disappeared," "improved," "poor," or "worsened." Responses of "disappeared" or "improved" manifestations suggested treatment effectiveness. Final clinical outcomes were evaluated using the Odom criteria. Changes in herniated disc size were evaluated by comparing the initial and final MRI scans. On the basis of these changes, the patients were divided into regression, no-change, or progression groups. We investigated the relationship between the Odom criteria and changes observed on MRI. Effectiveness rates were 89% for arm pain, 77% for arm numbness, 82% for neck and/or scapular pain, and 76% for arm paralysis. In total, 91 patients underwent repeated MRI. In 56 patients (62%), the size of the herniated disc decreased, but 31 patients (34%) exhibited no change in disc size. The regression group showed significantly better Odom criteria results than the no-change group. In conclusion, IDIS and SNRB for CR are not widely performed. However, other extremely effective therapies that can rapidly improve neuralgia should be considered before surgery. PMID:25797986

  7. Effect of TiO2 blocking layer on TiO2 nanorod arrays based dye sensitized solar cells

    Science.gov (United States)

    Sivakumar, R.; Paulraj, M.

    2016-05-01

    Highly ordered rutile titanium dioxide nanorod (TNR) arrays (1.2 to 6.2 μm thickness) were grown on TiO2 blocking layer chemically deposited on fluorine doped tin oxide (FTO) substrate and were used as photo-electrodes to fabricate dye sensitized solar cells (DSSC's). Homogeneous layer of TiO2 on FTO was achieved by using aqueous peroxo- titanium complex (PTC) solutions via chemical bath deposition. Structural and morphological properties of the prepared samples were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) measurements. TNR arrays (6.2 μm) with TiO2 blocking layer showed higher energy conversion efficiency (1.46%) than that without TiO2 blocking layer. The reason can be ascertained to the suppression of electron-hole recombination at the semiconductor/electrolyte interface by the effect of TiO2 blocking layer.

  8. Blocking of PDL-1 interaction enhances primary and secondary CD8 T cell response to herpes simplex virus-1 infection.

    Directory of Open Access Journals (Sweden)

    Rudragouda Channappanavar

    Full Text Available The blocking of programmed death ligand-1 (PDL-1 has been shown to enhance virus-specific CD8 T cell function during chronic viral infections. Though, how PDL-1 blocking at the time of priming affects the quality of CD8 T cell response to acute infections is not well understood and remains controversial. This report demonstrates that the magnitude of the primary and secondary CD8 T cell responses to herpes simplex virus-1 (HSV-1 infection is subject to control by PDL-1. Our results showed that after footpad HSV-1 infection, PD-1 expression increases on immunodominant SSIEFARL peptide specific CD8 T cells. Additionally, post-infection, the level of PDL-1 expression also increases on CD11c+ dendritic cells. Intraperitoneal administration of anti-PDL-1 monoclonal antibody given one day prior to and three days after cutaneous HSV-1 infection, resulted in a marked increase in effector and memory CD8 T cell response to SSIEFARL peptide. This was shown by measuring the quantity and quality of SSIEFARL-specific CD8 T cells by making use of ex-vivo assays that determine antigen specific CD8 T cell function, such as intracellular cytokine assay, degranulation assay to measure cytotoxicity and viral clearance. Our results are discussed in terms of the beneficial effects of blocking PDL-1 interactions, while giving prophylactic vaccines, to generate a more effective CD8 T cell response to viral infection.

  9. How do I perform hematopoietic progenitor cell selection?

    Science.gov (United States)

    Avecilla, Scott T; Goss, Cheryl; Bleau, Sharon; Tonon, Jo-Ann; Meagher, Richard C

    2016-05-01

    Graft-versus-host disease remains the most important source of morbidity and mortality associated with allogeneic stem cell transplantation. The implementation of hematopoietic progenitor cell (HPC) selection is employed by some stem cell processing facilities to mitigate this complication. Current cell selection methods include reducing the number of unwanted T cells (negative selection) and/or enriching CD34+ hematopoietic stem/progenitors (positive selection) using immunomagnetic beads subjected to magnetic fields within columns to separate out targeted cells. Unwanted side effects of cell selection as a result of T-cell reduction are primary graft failure, increased infection rates, delayed immune reconstitution, possible disease relapse, and posttransplant lymphoproliferative disease. The Miltenyi CliniMACS cell isolation system is the only device currently approved for clinical use by the Food and Drug Administration. It uses magnetic microbeads conjugated with a high-affinity anti-CD34 monoclonal antibody capable of binding to HPCs in marrow, peripheral blood, or umbilical cord blood products. The system results in significantly improved CD34+ cell recoveries (50%-100%) and consistent 3-log CD3+ T-cell reductions compared to previous generations of CD34+ cell selection procedures. In this article, the CliniMACS procedure is described in greater detail and the authors provide useful insight into modifications of the system. Successful implementation of cell selection procedures can have a significant positive clinical effect by greatly increasing the pool of donors for recipients requiring transplants. However, before a program implements cell selection techniques, it is important to consider the time and financial resources required to properly and safely perform these procedures. PMID:26919388

  10. A nanocomplex that is both tumor cell-selective and cancer gene-specific for anaplastic large cell lymphoma

    Directory of Open Access Journals (Sweden)

    Zu Youli

    2011-01-01

    Full Text Available Abstract Background Many in vitro studies have demonstrated that silencing of cancerous genes by siRNAs is a potential therapeutic approach for blocking tumor growth. However, siRNAs are not cell type-selective, cannot specifically target tumor cells, and therefore have limited in vivo application for siRNA-mediated gene therapy. Results In this study, we tested a functional RNA nanocomplex which exclusively targets and affects human anaplastic large cell lymphoma (ALCL by taking advantage of the abnormal expression of CD30, a unique surface biomarker, and the anaplastic lymphoma kinase (ALK gene in lymphoma cells. The nanocomplexes were formulated by incorporating both ALK siRNA and a RNA-based CD30 aptamer probe onto nano-sized polyethyleneimine-citrate carriers. To minimize potential cytotoxicity, the individual components of the nanocomplexes were used at sub-cytotoxic concentrations. Dynamic light scattering showed that formed nanocomplexes were ~140 nm in diameter and remained stable for more than 24 hours in culture medium. Cell binding assays revealed that CD30 aptamer probes selectively targeted nanocomplexes to ALCL cells, and confocal fluorescence microscopy confirmed intracellular delivery of the nanocomplex. Cell transfection analysis showed that nanocomplexes silenced genes in an ALCL cell type-selective fashion. Moreover, exposure of ALCL cells to nanocomplexes carrying both ALK siRNAs and CD30 RNA aptamers specifically silenced ALK gene expression, leading to growth arrest and apoptosis. Conclusions Taken together, our findings indicate that this functional RNA nanocomplex is both tumor cell type-selective and cancer gene-specific for ALCL cells.

  11. Remote Actuation of Magnetic Nanoparticles For Cancer Cell Selective Treatment Through Cytoskeletal Disruption.

    Science.gov (United States)

    Master, Alyssa M; Williams, Philise N; Pothayee, Nikorn; Pothayee, Nipon; Zhang, Rui; Vishwasrao, Hemant M; Golovin, Yuri I; Riffle, Judy S; Sokolsky, Marina; Kabanov, Alexander V

    2016-01-01

    Motion of micron and sub-micron size magnetic particles in alternating magnetic fields can activate mechanosensitive cellular functions or physically destruct cancer cells. However, such effects are usually observed with relatively large magnetic particles (>250 nm) that would be difficult if at all possible to deliver to remote sites in the body to treat disease. Here we show a completely new mechanism of selective toxicity of superparamagnetic nanoparticles (SMNP) of 7 to 8 nm in diameter to cancer cells. These particles are coated by block copolymers, which facilitates their entry into the cells and clustering in the lysosomes, where they are then magneto-mechanically actuated by remotely applied alternating current (AC) magnetic fields of very low frequency (50 Hz). Such fields and treatments are safe for surrounding tissues but produce cytoskeletal disruption and subsequent death of cancer cells while leaving healthy cells intact. PMID:27644858

  12. Highly protein-resistant coatings and suspension cell culture thereon from amphiphilic block copolymers prepared by RAFT polymerization.

    Science.gov (United States)

    Haraguchi, Kazutoshi; Kubota, Kazuomi; Takada, Tetsuo; Mahara, Saori

    2014-06-01

    Novel amphiphilic block copolymers composed of hydrophobic (poly(2-methoxyethyl acrylate): M) and hydrophilic (poly(N,N-dimethylacrylamide): D) segments were synthesized by living radical polymerization: a reversible addition-fragmentation chain-transfer polymerization. Two types of amphiphilic block copolymers, triblock (MDM) and 4-arm block ((MD)4) copolymers with specific compositions (D/M = (750-1500)/250), were prepared by a versatile one-pot synthesis. These copolymers show good adhesion to various types of substrates (e.g., polystyrene, polycarbonate, polypropylene, Ti, and glass), and the surface coating showed high protein repellency and a low contact angle for water, regardless of the substrate. The two opposing characteristics of high protein repellency and good substrate adhesion were achieved by the combined effects of the molecular architecture of the block copolymers, the high molecular weight, and the characteristics of each segment, that is, low protein adsorption capability of both segments and low glass transition temperature of the hydrophobic segment. Further, a polystyrene dish coated with the MDM block copolymer could be sterilized by γ-ray irradiation and used as a good substrate for a suspension cell culture that exhibits low cell adhesion and good cell growth.

  13. Highly protein-resistant coatings and suspension cell culture thereon from amphiphilic block copolymers prepared by RAFT polymerization.

    Science.gov (United States)

    Haraguchi, Kazutoshi; Kubota, Kazuomi; Takada, Tetsuo; Mahara, Saori

    2014-06-01

    Novel amphiphilic block copolymers composed of hydrophobic (poly(2-methoxyethyl acrylate): M) and hydrophilic (poly(N,N-dimethylacrylamide): D) segments were synthesized by living radical polymerization: a reversible addition-fragmentation chain-transfer polymerization. Two types of amphiphilic block copolymers, triblock (MDM) and 4-arm block ((MD)4) copolymers with specific compositions (D/M = (750-1500)/250), were prepared by a versatile one-pot synthesis. These copolymers show good adhesion to various types of substrates (e.g., polystyrene, polycarbonate, polypropylene, Ti, and glass), and the surface coating showed high protein repellency and a low contact angle for water, regardless of the substrate. The two opposing characteristics of high protein repellency and good substrate adhesion were achieved by the combined effects of the molecular architecture of the block copolymers, the high molecular weight, and the characteristics of each segment, that is, low protein adsorption capability of both segments and low glass transition temperature of the hydrophobic segment. Further, a polystyrene dish coated with the MDM block copolymer could be sterilized by γ-ray irradiation and used as a good substrate for a suspension cell culture that exhibits low cell adhesion and good cell growth. PMID:24773089

  14. Application of non-small cell lung cancer pleural effusion cell blocks in molecular pathological detection

    Institute of Scientific and Technical Information of China (English)

    Ying Zhang; Nan Jiang; Dongdong Qian; Xiangzhou Li; Yu Zhou; Jia Mei; Xiaohui Cao

    2014-01-01

    Objective:The tumor tissues used in molecular pathological detection were usual y obtained by surgery, which would cause trauma and may not be suitable for the terminal cancer patients. This paper evaluated the value of the non-smal celllung cancer (NSCLC) pleural ef usion cellblocks as tumor tissues replacement materials in the application of molecular pathological detection. Methods: Tumor cells were made into cellblocks through stratified centrifugal from 30 NSCLC pa-tients with the pleural ef usion. The immunohistochemistry, fluorescence in situ hybridization (FISH) and gene sequencing methods were employed in our experiments. Results:The tumor cells of cellblock section were rich and could keep part of histological structure. Immunohistochemistry staining could assist diagnosis and tumor parting. Epidermal growth factor receptor (EGFR) FISH-positive was found in 33.33%of the group, high polysomy in 6 cases, amplification in 4 cases. EGFR gene mutations were found in 8 cases of 30 samples, with an incidence of 26.67%, 6 cases were detected in the exon 19, and 2 cases were detected in the exon 21. Conclusion:The NSCLC pleural ef usion cellblocks are useful for the diagnosis and determining the primary source of tumor, instructed targeted therapy.

  15. UV laser mediated cell selective destruction by confocal microscopy

    Directory of Open Access Journals (Sweden)

    Giangrande Angela

    2008-04-01

    Full Text Available Abstract Analysis of cell-cell interactions, cell function and cell lineages greatly benefits selective destruction techniques, which, at present, rely on dedicated, high energy, pulsed lasers and are limited to cells that are detectable by conventional microscopy. We present here a high resolution/sensitivity technique based on confocal microscopy and relying on commonly used UV lasers. Coupling this technique with time-lapse enables the destruction and following of any cell(s in any pattern(s in living animals as well as in cell culture systems.

  16. Combined MET inhibition and topoisomerase I inhibition block cell growth of small cell lung cancer.

    Science.gov (United States)

    Rolle, Cleo E; Kanteti, Rajani; Surati, Mosmi; Nandi, Suvobroto; Dhanasingh, Immanuel; Yala, Soheil; Tretiakova, Maria; Arif, Qudsia; Hembrough, Todd; Brand, Toni M; Wheeler, Deric L; Husain, Aliya N; Vokes, Everett E; Bharti, Ajit; Salgia, Ravi

    2014-03-01

    Small cell lung cancer (SCLC) is a devastating disease, and current therapies have not greatly improved the 5-year survival rates. Topoisomerase (Top) inhibition is a treatment modality for SCLC; however, the response is short lived. Consequently, our research has focused on improving SCLC therapeutics through the identification of novel targets. Previously, we identified MNNG HOS transforming gene (MET) to be overexpressed and functional in SCLC. Herein, we investigated the therapeutic potential of combinatorial targeting of MET using SU11274 and Top1 using 7-ethyl-10-hydroxycamptothecin (SN-38). MET and TOP1 gene copy numbers and protein expression were determined in 29 patients with limited (n = 11) and extensive (n = 18) disease. MET gene copy number was significantly increased (>6 copies) in extensive disease compared with limited disease (P = 0.015). Similar TOP1 gene copy numbers were detected in limited and extensive disease. Immunohistochemical staining revealed a significantly higher Top1 nuclear expression in extensive (0.93) versus limited (0.15) disease (P = 0.04). Interestingly, a significant positive correlation was detected between MET gene copy number and Top1 nuclear expression (r = 0.5). In vitro stimulation of H82 cells revealed hepatocyte growth factor (HGF)-induced nuclear colocalization of p-MET and Top1. Furthermore, activation of the HGF/MET axis enhanced Top1 activity, which was abrogated by SU11274. Combination of SN-38 with SU11274 dramatically decreased SCLC growth as compared with either drug alone. Collectively, these findings suggest that the combinatorial inhibition of MET and Top1 is a potentially efficacious treatment strategy for SCLC. PMID:24327519

  17. BMGE (Block Mapping and Gathering with Entropy: a new software for selection of phylogenetic informative regions from multiple sequence alignments

    Directory of Open Access Journals (Sweden)

    Gribaldo Simonetta

    2010-07-01

    Full Text Available Abstract Background The quality of multiple sequence alignments plays an important role in the accuracy of phylogenetic inference. It has been shown that removing ambiguously aligned regions, but also other sources of bias such as highly variable (saturated characters, can improve the overall performance of many phylogenetic reconstruction methods. A current scientific trend is to build phylogenetic trees from a large number of sequence datasets (semi-automatically extracted from numerous complete genomes. Because these approaches do not allow a precise manual curation of each dataset, there exists a real need for efficient bioinformatic tools dedicated to this alignment character trimming step. Results Here is presented a new software, named BMGE (Block Mapping and Gathering with Entropy, that is designed to select regions in a multiple sequence alignment that are suited for phylogenetic inference. For each character, BMGE computes a score closely related to an entropy value. Calculation of these entropy-like scores is weighted with BLOSUM or PAM similarity matrices in order to distinguish among biologically expected and unexpected variability for each aligned character. Sets of contiguous characters with a score above a given threshold are considered as not suited for phylogenetic inference and then removed. Simulation analyses show that the character trimming performed by BMGE produces datasets leading to accurate trees, especially with alignments including distantly-related sequences. BMGE also implements trimming and recoding methods aimed at minimizing phylogeny reconstruction artefacts due to compositional heterogeneity. Conclusions BMGE is able to perform biologically relevant trimming on a multiple alignment of DNA, codon or amino acid sequences. Java source code and executable are freely available at ftp://ftp.pasteur.fr/pub/GenSoft/projects/BMGE/.

  18. Differentiation of human stem cells is promoted by amphiphilic pluronic block copolymers

    Directory of Open Access Journals (Sweden)

    Doğan A

    2012-09-01

    Full Text Available Aysegül Doğan,1 Mehmet E Yalvaç,1,2 Fikrettin Şahin,1 Alexander V Kabanov,3–5 András Palotás,6 Albert A Rizvanov71Department of Genetics and BioEngineering, College of Engineering and Architecture, Yeditepe University, Istanbul, Turkey; 2Center for Gene Therapy, Nationwide Children's Hospital, Ohio State University, Columbus, OH, USA; 3Center for Drug Delivery and Nanomedicine, 4Department of Pharmaceutical Sciences, College of Pharmacy, Durham Research Center, University of Nebraska Medical Center, Omaha, NE, USA; 5Laboratory of Chemical Design of Bio-nano-materials, Department of Chemistry, Mikhail V Lomonosov Moscow State University, Moscow, Russia; 6Asklepios-Med, Szeged, Hungary; 7Institute of Fundamental Medicine and Biology, Kazan (Volga Region Federal University, Kazan, RussiaAbstract: Stem cell usage provides novel avenues of tissue regeneration and therapeutics across disciplines. Apart from ethical considerations, the selection and amplification of donor stem cells remain a challenge. Various biopolymers with a wide range of properties have been used extensively to deliver biomolecules such as drugs, growth factors and nucleic acids, as well as to provide biomimetic surface for cellular adhesion. Using human tooth germ stem cells with high proliferation and transformation capacity, we have investigated a range of biopolymers to assess their potential for tissue engineering. Tolerability, toxicity, and their ability to direct differentiation were evaluated. The majority of pluronics, consisting of both hydrophilic and hydrophobic poly(ethylene oxide chains, either exerted cytotoxicity or had no significant effect on human tooth germ stem cells; whereas F68 increased the multi-potency of stem cells, and efficiently transformed them into osteogenic, chondrogenic, and adipogenic tissues. The data suggest that differentiation and maturation of stem cells can be promoted by selecting the appropriate mechanical and chemical

  19. Evidence for Existence of Immunoglobulins that Block Ovarian Granulosa Cell Growth in Vitro. A Putative Role in Resistant Ovary Syndrome?

    NARCIS (Netherlands)

    WEISSENBRUCH, MIRJAM M. van; HOEK, ANNEMIEKE; VLIET-BLEEKER, INGRID van; SCHOEMAKER, JOOP; DREXHAGE, HEMMO

    1991-01-01

    The sera of 26 patients with premature ovarian failure were examined in order to detect immunoglobulin-G (IgGs) that can block FSH-induced in vitro granulosa cell DNA synthesis via, a Feulgen cytochemical bioassay system. The IgGs of four patients with polycystic ovary-like disease, five postmenopau

  20. Screening system of blocking agents of the receptor for advanced glycation endproducts in cells using fluorescence.

    Science.gov (United States)

    Jung, Dong Ho; Kim, Young Sook; Kim, Jin Sook

    2012-01-01

    Activation of the receptor for advanced glycation endproducts (RAGE) triggers cellular responses implicated in the pathogenesis of diabetic complications; blockade of RAGE has been shown to inhibit the development of diabetic complications. To develop a screening system to identify novel disruptors of advanced glycation endproducts (AGE)-RAGE binding, we used an AGE-RAGE binding system in RAGE-overexpressing cells; test compounds were screened using this system. To construct human RAGE-overexpressing cells, mouse mesangial cells (MMCs) were stably transfected with the pcDNA-human RAGE (hRAGE) vector and selected under 1 mg/mL gentamicin (G418). RAGE expression in hRAGE-overexpressing MMCs was analyzed by Western blotting with specific RAGE antibody. To identify novel disruptors of AGE-RAGE binding, 50 single compounds and AGE-bovine serum albumin (BSA)-Alexa 488 (AGE-BSA labeled with Alexa 488) were treated to the hRAGE-overexpressing MMCs. Nonbinding AGE-BSA-Alexa 488 was washed and fluorescence measured by microtiter plate reader (excitation wavelength, 485 nm; emission wavelength, 528 nm). In hRAGE-overexpressing cells, only treatment with AGE-BSA-Alexa 488 significantly increased fluorescence intensity in a dose-dependent manner. Of 50 compounds tested, genistein disrupted AGE-RAGE binding in a dose-dependent manner. This AGE-RAGE binding system using AGE-BSA-Alexa 488 in hRAGE-overexpressing cells was suitable for screening of agents that disrupt AGE-hRAGE binding.

  1. CEP-701 and CEP-751 inhibit constitutively activated RET tyrosine kinase activity and block medullary thyroid carcinoma cell growth.

    Science.gov (United States)

    Strock, Christopher J; Park, Jong-In; Rosen, Mark; Dionne, Craig; Ruggeri, Bruce; Jones-Bolin, Susan; Denmeade, Samuel R; Ball, Douglas W; Nelkin, Barry D

    2003-09-01

    All of the cases of medullary thyroid carcinoma (MTC) express the RET receptor tyrosine kinase. In essentially all of the hereditary cases and approximately 40% of the sporadic cases of MTC, the RET kinase is constitutively activated by mutation. This suggests that RET may be an effective therapeutic target for treatment of MTC. We show that the indolocarbazole derivatives, CEP-701 and CEP-751, inhibit RET in MTC cells. These compounds effectively inhibit RET phosphorylation in a dose-dependent manner at concentrations <100 nM in 0.5% serum and at somewhat higher concentrations in the presence of 16% serum. They also blocked the growth of these MTC cells in culture. CEP-751 and its prodrug, CEP-2563, also inhibited tumor growth in MTC cell xenografts. These results show that inhibiting RET can block the growth of MTC cells and may have a therapeutic benefit in MTC.

  2. Ion-Selective Detection with Glass Nanopipette for Living Cells

    Science.gov (United States)

    Takami, T.; Son, J. W.; Kang, E. J.; Deng, X. L.; Kawai, T.; Lee, S.-W.; Park, B. H.

    2013-05-01

    We developed a method to probe local ion concentration with glass nanopipette in which poly(vinyl chloride) membrane containing ionophore for separate ion detection is prepared. Here we demonstrate how ion-selective detections are available for living cells such as HeLa cell, rat vascular myocyte, and neuron cell.

  3. Synergistic interaction between selective drugs in cell populations models.

    Directory of Open Access Journals (Sweden)

    Victoria Doldán-Martelli

    Full Text Available The design of selective drugs and combinatorial drug treatments are two of the main focuses in modern pharmacology. In this study we use a mathematical model of chimeric ligand-receptor interaction to show that the combination of selective drugs is synergistic in nature, providing a way to gain optimal selective potential at reduced doses compared to the same drugs when applied individually. We use a cell population model of proliferating cells expressing two different amounts of a target protein to show that both selectivity and synergism are robust against variability and heritability in the cell population. The reduction in the total drug administered due to the synergistic performance of the selective drugs can potentially result in reduced toxicity and off-target interactions, providing a mechanism to improve the treatment of cell-based diseases caused by aberrant gene overexpression, such as cancer and diabetes.

  4. The Effect of Single-Nucleotide Polymorphism Marker Selection on Patterns of Haplotype Blocks and Haplotype Frequency Estimates

    OpenAIRE

    Nothnagel, Michael; Rohde, Klaus

    2005-01-01

    The definition of haplotype blocks of single-nucleotide polymorphisms (SNPs) has been proposed so that the haplotypes can be used as markers in association studies and to efficiently describe human genetic variation. The International Haplotype Map (HapMap) project to construct a comprehensive catalog of haplotypic variation in humans is underway. However, a number of factors have already been shown to influence the definition of blocks, including the population studied and the sample SNP den...

  5. Anti-S100A4 antibody suppresses metastasis formation by blocking stroma cell invasion

    DEFF Research Database (Denmark)

    Klingelhöfer, Jörg; Grum-Schwensen, Birgitte; Beck, Mette K;

    2012-01-01

    microenvironment, making it an attractive target for anti-cancer therapy. In this study, we produced a function-blocking anti-S100A4 monoclonal antibody with metastasis-suppressing activity. Antibody treatment significantly reduced metastatic burden in the lungs of experimental animals by blocking the recruitment...

  6. Intercellular redistribution of cAMP underlies selective suppression of cancer cell growth by connexin26.

    Directory of Open Access Journals (Sweden)

    Anjana Chandrasekhar

    Full Text Available Connexins (Cx, which constitute gap junction intercellular channels in vertebrates, have been shown to suppress transformed cell growth and tumorigenesis, but the mechanism(s still remain largely speculative. Here, we define the molecular basis by which Cx26, but less frequently Cx43 or Cx32, selectively confer growth suppression on cancer cells. Functional intercellular coupling is shown to be required, producing partial blocks of the cell cycle due to prolonged activation of several mitogenic kinases. PKA is both necessary and sufficient for the Cx26 induced growth inhibition in low serum and the absence of anchorage. Activation of PKA was not associated with elevated cAMP levels, but appeared to result from a redistribution of cAMP throughout the cell population, eliminating the cell cycle oscillations in cAMP required for efficient cell cycle progression. Cx43 and Cx32 fail to mediate this redistribution as, unlike Cx26, these channels are closed during the G2/M phase of the cell cycle when cAMP levels peak. Comparisons of tumor cell lines indicate that this is a general pattern, with growth suppression by connexins occurring whenever cAMP oscillates with the cell cycle, and the gap junction remain open throughout the cell cycle. Thus, gap junctional coupling, in the absence of any external signals, provides a general means to limit the mitotic rate of cell populations.

  7. Advancing tandem solar cells by spectrally selective multilayer intermediate reflectors.

    Science.gov (United States)

    Hoffmann, Andre; Paetzold, Ulrich W; Zhang, Chao; Merdzhanova, Tsvetelina; Lambertz, Andreas; Ulbrich, Carolin; Bittkau, Karsten; Rau, Uwe

    2014-08-25

    Thin-film silicon tandem solar cells are composed of an amorphous silicon top cell and a microcrystalline silicon bottom cell, stacked and connected in series. In order to match the photocurrents of the top cell and the bottom cell, a proper photon management is required. Up to date, single-layer intermediate reflectors of limited spectral selectivity are applied to match the photocurrents of the top and the bottom cell. In this paper, we design and prototype multilayer intermediate reflectors based on aluminum doped zinc oxide and doped microcrystalline silicon oxide with a spectrally selective reflectance allowing for improved current matching and an overall increase of the charge carrier generation. The intermediate reflectors are successfully integrated into state-of-the-art tandem solar cells resulting in an increase of overall short-circuit current density by 0.7 mA/cm(2) in comparison to a tandem solar cell with the standard single-layer intermediate reflector. PMID:25322181

  8. Multicompartment micellar aggregates of linear ABC amphiphiles in solvents selective for the C block: A Monte Carlo simulation

    KAUST Repository

    Zhu, Yutian

    2012-01-01

    In the current study, we applied the Monte Carlo method to study the self-assembly of linear ABC amphiphiles composed of two solvophobic A and B blocks and a solvophilic C block. A great number of multicompartment micelles are discovered from the simulations and the detailed phase diagrams for the ABC amphiphiles with different block lengths are obtained. The simulation results reveal that the micellar structure is largely controlled by block length, solvent quality, and incompatibility between the different block types. When the B block is longer than or as same as the terminal A block, a rich variety of micellar structures can be formed from ABC amphiphiles. By adjusting the solvent quality or incompatibility between the different block types, multiple morphological transitions are observed. These morphological sequences are well explained and consistent with all the previous experimental and theoretical studies. Despite the complexity of the micellar structures and morphological transitions observed for the self-assembly of ABC amphiphiles, two important common features of the phase behavior are obtained. In general, the micellar structures obtained in the current study can be divided into zero-dimensional (sphere-like structures, including bumpy-surfaced spheres and sphere-on-sphere structures), one-dimensional (cylinder-like structures, including rod and ring structures), two-dimensional (layer-like structures, including disk, lamella and worm-like and hamburger structures) and three-dimensional (vesicle) structures. It is found that the micellar structures transform from low- to high- dimensional structures when the solvent quality for the solvophobic blocks is decreased. In contrast, the micellar structures transform from high- to low-dimensional structures as the incompatibility between different block types increases. Furthermore, several novel micellar structures, such as the CBABC five-layer vesicle, hamburger, CBA three-layer ring, wormlike shape with

  9. p16 INK4a immunocytochemistry on cell blocks as an adjunct to cervical cytology: Potential reflex testing on specially prepared cell blocks from residual liquid-based cytology specimens

    Directory of Open Access Journals (Sweden)

    Vinod B Shidham

    2011-01-01

    Full Text Available Background: p16 INK4a (p16 is a well-recognized surrogate molecular marker for human papilloma virus (HPV related squamous dysplasia. Our hypothesis is that the invasive interventions and related morbidities could be avoided by objective stratification of positive cytologic interpretations by p16 immunostaining of cell block sections of cytology specimens. Materials and Methods: Nuclear immunoreactivity for p16 was evaluated in cell block sections in 133 adequate cases [20 negative for intraepithelial lesion or malignancy, 28 high-grade squamous intraepithelial lesion (HSIL, 50 low-grade squamous intraepithelial lesion (LSIL, 21 atypical squamous cells, cannot exclude HSIL (ASC-H, and 14 atypical squamous cells of undetermined significance (ASCUS] and analyzed with cervical biopsy results. Results: (a HSIL cytology (28: 21 (75% were p16 positive (11 biopsies available - 92% were positive for cervical intraepithelial neoplasia (CIN 1 and above and 7 (25% were p16 negative (3 biopsies available - all showed only HPV with small atypical parakeratotic cells. (b LSIL cytology (50: 13 (26% cases were p16 positive (12 biopsies available - all were CIN1 or above and 37 (74% were p16 negative (12 biopsies available - all negative for dysplasia. However, 9 (75% of these biopsies showed HPV. (c ASC-H cytology (21: 14 (67% were p16 positive (6 biopsies available - 5 showed CIN 3/Carcinoma in situ/Ca and 1 showed CIN 1 with possibility of under-sampling. Cytomorphologic re-review favored HSIL and 7 (33% were p16 negative (5 biopsies available - 3 negative for dysplasia. Remaining 2 cases - 1 positive for CIN 3 and 1 showed CIN 1 with scant ASC-H cells on cytomorphologic re-review with possibility under-sampling in cytology specimen. (d ASCUS cytology (14: All (100% were p16 negative on cell block sections of cervical cytology specimen. HPV testing performed in last 6 months in 7 cases was positive in 3 (43% cases. Conclusion: p16 immunostaining on cell block

  10. Seamount characteristics and mine-site model applied to exploration- and mining-lease-block selection for cobalt-rich ferromanganese crusts

    Science.gov (United States)

    Hein, James R.; Conrad, Tracey A.; Dunham, Rachel E.

    2009-01-01

    Regulations are being developed through the International Seabed Authority (ISBA) for the exploration and mining of cobalt-rich ferromanganese crusts. This paper lays out geologic and geomorphologic criteria that can be used to determine the size and number of exploration and mine-site blocks that will be the focus of much discussion within the ISBA Council deliberations. The surface areas of 155 volcanic edifices in the central equatorial Pacific were measured and used to develop a mine-site model. The mine-site model considers areas above 2,500 m water depth as permissive, and narrows the general area available for exploration and mining to 20% of that permissive area. It is calculated that about eighteen 100 km2 explora-tion blocks, each composed of five 20km2 contiguous sub-blocks, would be adequate to identify a 260 km2 20-year-mine site; the mine site would be composed of thirteen of the 20km2 sub-blocks. In this hypothetical example, the 260 km2 mine site would be spread over four volcanic edifices and comprise 3.7% of the permissive area of the four edifices and 0.01% of the total area of those four edifices. The eighteen 100km2 exploration blocks would be selected from a limited geographic area. That confinement area is defined as having a long dimension of not more than 1,000 km and an area of not more than 300,000 km2.

  11. Selectable-Tip Corrosion-Testing Electrochemical Cell

    Science.gov (United States)

    Lomness, Janice; Hintze, Paul

    2008-01-01

    The figure depicts aspects of an electrochemical cell for pitting- corrosion tests of material specimens. The cell is designed to generate a region of corrosion having a pit diameter determined by the diameter of a selectable tip. The average depth of corrosion is controlled by controlling the total electric charge passing through the cell in a test. The cell is also designed to produce minimal artifacts associated with crevice corrosion. There are three selectable tips, having diameters of 0.1 in. (0.254 cm), 0.3 in. (0.762 cm), and 0.6 in. (1.524 cm), respectively.

  12. Limited selection of sodium channel blocking toxin-producing bacteria from paralytic shellfish toxin-contaminated mussels (Aulacomya ater).

    Science.gov (United States)

    Vásquez, Mónica; Grüttner, Carol; Möeller, Blanca; Moore, Edward R B

    2002-01-01

    Paralytic shellfish toxins (PSTs) are sodium channel blocking (SCB) toxins, produced by cyanobacteria, as well as by marine dinoflagellates and their associated bacteria, and cause serious health and economic concern worldwide. In a previous study, approximately 70% of the bacteria enriched from PST-contaminated shellfish tissue and isolated on marine agar medium were observed to produce SCB toxins. In the study reported here, the high percentage of cultivable toxigenic bacteria is demonstrated to be obtained through a marked selection on marine agar medium. The cultivable as well as the total bacterial diversity associated with PST-contaminated shellfish collected from the Magallanes region in the south of Chile has been analysed. Approximately 80% of bacterial isolates, analysed by restriction analysis of PCR amplified ribosomal DNA (i.e., ARDRA fingerprinting), were limited to only two genotypic OTUs (operational taxonomic unit). Sequence determination and analysis of the 16S rDNA from representative isolates of both OTUs established them to be closely related to species of the Psychrobacter genus of the gamma-subclass of the Proteobacteria. The total bacterial diversity in the shellfish was further analysed, using a cultivation-independent strategy of extraction of total DNA from contaminated tissue, PCR-amplification of bacterial 16S rRNA genes, cloning of the PCR products and analysis of the cloned 16S rDNA sequence types by fingerprinting and sequencing. Only 2% of the cloned sequence types corresponded to species of the Psychrobacter genus. The 16S rDNA sequence types detected clustered with species of the y-Proteobacteria subclass, the Cytophaga-Flexibacter-Bacteroides (CFB), the Fusobacteria and the Firmicutes phyla. The level of diversity observed within the libraries of cloned 16S rDNA was markedly greater than that observed among isolates obtained through marine agar enrichment cultures from the same shellfish tissue. Additionally the predominant

  13. Relief of preintegration inhibition and characterization of additional blocks for HIV replication in primary mouse T cells.

    Directory of Open Access Journals (Sweden)

    Jing-xin Zhang

    Full Text Available Development of a small animal model to study HIV replication and pathogenesis has been hampered by the failure of the virus to replicate in non-primate cells. Most studies aimed at achieving replication in murine cells have been limited to fibroblast cell lines, but generating an appropriate model requires overcoming blocks to viral replication in primary T cells. We have studied HIV-1 replication in CD4(+ T cells from human CD4/CCR5/Cyclin T1 transgenic mice. Expression of hCD4 and hCCR5 in mouse CD4(+ T cells enabled efficient entry of R5 strain HIV-1. In mouse T cells, HIV-1 underwent reverse transcription and nuclear import as efficiently as in human T cells. In contrast, chromosomal integration of HIV-1 proviral DNA was inefficient in activated mouse T cells. This process was greatly enhanced by providing a secondary T cell receptor (TCR signal after HIV-1 infection, especially between 12 to 24 h post infection. This effect was specific for primary mouse T cells. The pathways involved in HIV replication appear to be PKCtheta-, CARMA1-, and WASp-independent. Treatment with Cyclosporin A (CsA further relieved the pre-integration block. However, transcription of HIV-1 RNA was still reduced in mouse CD4(+ T cells despite expression of the hCyclin T1 transgene. Additional post-transcriptional defects were observed at the levels of Gag expression, Gag processing, Gag release and virus infectivity. Together, these post-integration defects resulted in a dramatically reduced yield of infectious virus (300-500 fold after a single cycle of HIV-1 replication. This study implies the existence of host factors, in addition to those already identified, that are critical for HIV-1 replication in mouse cells. This study also highlights the differences between primary T cells and cell lines regarding pre-integration steps in the HIV-1 replication cycle.

  14. Cyclosporin A does not block the phorbol ester - protein kinase C regulated pathway of T cell activation

    International Nuclear Information System (INIS)

    The T cell line Jurkat can be induced to produce interleukin-2 (IL-2) in vitro by a combination of two stimuli: (1) A stimulus that increases cytoplasmic free Ca++ concentration plus (2) phorbol ester (PMA). No. IL-2 production is induced with either stimulus alone. The T cell line HUT 78 responds to the same combination of stimuli, however also produces low amounts of IL-2 in response to PMA only. After HUT 78 cells were pretreated with the nucleoside analog 5-azacytidine (AZA) they produced maximal amounts of IL-2 in response to PMA alone. Cyclosporin A (CsA) has been shown to completely block the two stimulus-induced IL-2 production in Jurkat at a pretranslational level. In contrast, the low level of IL-2 production in HUT 78 and the high level of IL-2 production in AZA-treated HUT 78 induced by PMA only is not inhibited by CsA. Additionally we demonstrated that CsA did not inhibit activation of protein kinase C, the primary target enzyme in PMA induced cell activation. The presented data suggest that CsA does not globally block lymphokine expression but rather interferes with signaling events in T cell activation. It appears that CsA blocks the pathway controlled by either Ca++ alone or Ca++ in combination with PMA, but not activation signaling regulated by PMA induced activation of protein kinase C alone

  15. Nanoporous TiO{sub 2} aerogel blocking layer with enhanced efficiency for dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Zheng-Ying [State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050 (China); Graduate University of Chinese Academy of Sciences, Beijing 100039 (China); Gao, Xiang-Dong, E-mail: xdgao@mail.sic.ac.cn [State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050 (China); Li, Xiao-Min [State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050 (China); Jiang, Zheng-Wu; Huang, Yu-Di [Key Laboratory of Advanced Civil Engineering Materials of Ministry of Education, Tongji University, 48000 Cao’an Road, Shanghai 201804 (China)

    2014-03-25

    Highlights: • TiO{sub 2} aerogel film was used as the blocking layer in the photoanode of DSSC. • The film was deposited via sol–gel and ambient-drying process sintering at 500 °C. • Power conversion efficiency was improved by 36% on P25 based photoanode. • Greatly inhibited recombination and enhanced electron lifetime were observed. • The slow diffusion rate of I{sub 3}{sup -} ions in small pores of aerogel plays a key role. -- Abstract: TiO{sub 2} aerogel film possessing nanoporous feature was used as the blocking layer between fluorine-doped tin oxide (FTO) substrate and mesoporous TiO{sub 2} layer in dye-sensitized solar cell (DSSC). TiO{sub 2} aerogel film was deposited on FTO glass via sol–gel and ambient drying processes and sintered at 500 °C, which exhibited the crystallite size of 5–25 nm, the pore size of 3–10 nm, and the thickness of ∼320 nm. Brunauer–Emmett–Teller (BET) analysis confirmed its nanoporous feature and average pore size of 3.8 nm after annealing at 500 °C. In addition, TiO{sub 2} aerogel film showed good interfacial adhesion with FTO and mesoporous TiO{sub 2} layer, high transmittance over 70% in the visible-near infrared band, and large band gap of 3.67 eV. The DSSC device based on this aerogel blocking layer showed obviously enhanced photocurrent density (J{sub sc}) and open-circuit voltage (V{sub oc}) compared with the cell without blocking layer. The highest conversion efficiency of 6.0% was achieved for P25 TiO{sub 2} mesoporous photoanode based on the aerogel blocking layer, improved by 36% than the control cell. The much decreased recombination frequency (aerogel cell: 11.9 Hz; control cell: 31.5 Hz) observed in Nyquist plots, together with the much prolonged electron lifetime (aerogel cell: ∼1 s; control cell: 0.02–0.1 s at 0.2–0.55 V) obtained from open-circuit voltage decay curves, indicated that the increased electron life and retarded recombination at FTO/electrolyte interface were primarily

  16. T cell depleted haploidentical transplantation: positive selection

    Directory of Open Access Journals (Sweden)

    Franco Aversa

    2011-06-01

    Full Text Available Interest in mismatched transplantation arises from the fact that a suitable one-haplotype mismatched donor is immediately available for virtually all patients, particularly for those who urgently need an allogenic transplant. Work on one haplotype-mismatched transplants has been proceeding for over 20 years all over the world and novel transplant techniques have been developed. Some centres have focused on the conditioning regimens and post transplant immune suppression; others have concentrated on manipulating the graft which may be a megadose of extensively T celldepleted or unmanipulated progenitor cells. Excellent engraftment rates are associated with a very low incidence of acute and chronic GVHD and regimen-related mortality even in patients who are over 50 years old. Overall, event-free survival and transplant-related mortality compare favourably with reports on transplants from sources of stem cells other than the matched sibling.

  17. Selective Function of PKC-θ in T cells

    Institute of Scientific and Technical Information of China (English)

    Santhakumar Manicassamy; Sonal Gupta; Zuoming Sun

    2006-01-01

    T cell activation is a critical process in initiating adaptive immune response since only through this process the na(i)ve antigen specific T cells differentiate into armed effector T cells that mediate the actual immune response.During T cell activation, na(i)ve T cells undergo clonal expansion and acquire the capability to kill target cells infected with pathogens or produce cytokines essential for regulating immune response. Inappropriate activation or inactivation of T cells leads to autoimmunity or severe immunodeficiencies. PKC-θ is selectively expressed in T cells and required for mediating T cell activation process. Mice deficient in PKC-θ exhibit defects in T cell activation, survival and activation-inducedcell death. PKC-θ selectively translocates to immunological synapse and mediates the signals required for activation of NF-κB, AP1 and NFAT that are essential for T cell activation.Furthermore, PKC-θ-/- mice displayed multiple defects in the development of T cell-mediated immune responses in vivo. PKC-θ is thus a critical molecule that regulates T cell function at multiple stages in T cell-mediated immune responses in vivo. Cellular & Molecular Immunology. 2006;3(4):263-270.

  18. Role of Liquid-based Cytology and Cell Block in the Diagnosis of Endometrial Lesions

    Institute of Scientific and Technical Information of China (English)

    Hui Zhang; Jia Wen; Pi-Li Xu; Rui Chen; Xi Yang; Lian-Er Zhou; Ping Jiang

    2016-01-01

    Background:Liquid-based cytology (LBC) offers an altemative method to biopsy in screening endometrial cancer.Cell block (CB),prepared by collecting residual cytological specimen,represents a novel method to supplement the diagnosis of endometrial cytology.This study aimed to compare the specimen adequacy and diagnostic accuracy of LBC and CB in the diagnosis of endometrial lesions.Methods:A total of 198 women with high risks of endometrial carcinoma (EC) from May 2014 to April 2015 were enrolled in this study.The cytological specimens were collected by the endometrial sampler (SAP-1) followed by histopathologic evaluation of dilatation and curettage or biopsy guided by hysteroscopy.The residual cytological specimens were processed into paraffin-embedded CB after LBC preparation.Diagnostic accuracies of LBC and CB for detecting endometrial lesions were correlated with histological diagnoses.Chi-square test was used to compare the specimen adequacies of LBC and CB.Results:The specimen inadequate rate of CB was significantly higher than that of LBC (22.2% versus 7.1%,P < 0.01).There were 144 cases with adequate specimens for LBC and CB preparation.Among them,29 cases were atypical endometrial hyperplasia (11 cases) or carcinoma (18 cases) confirmed by histology evaluation.Taking atypical hyperplasia and carcinoma as positive,the diagnostic accuracy of CB was 95.1% while it was 93.8% in LBC.When combined LBC with CB,the diagnostic accuracy was improved to 95.8%,with a sensitivity of 89.7% and specificity of 97.4%.Conclusions:CB is a feasible and reproducible adjuvant method for screening endometrial lesions.A combination of CB and LBC can improve the diagnostic accuracy of endometrial lesions.

  19. A multiscale modeling study of loss processes in block-copolymer-based solar cell nanodevices

    Science.gov (United States)

    Donets, Sergii; Pershin, Anton; Christlmaier, Martin J. A.; Baeurle, Stephan A.

    2013-03-01

    Flexible photovoltaic devices possess promising perspectives in opto-electronic technologies, where high mobility and/or large-scale applicability are important. However, their usefulness in such applications is currently still limited due to the low level of optimization of their performance and durability. For the improvement of these properties, a better understanding and control of small-scale annihilation phenomena involved in the photovoltaic process, such as exciton loss and charge carrier loss, is necessary, which typically implicates multiple length- and time-scales. Here, we study the causes for their occurrence on the example of nanostructured diblock- and triblock-copolymer systems by making use of a novel solar-cell simulation algorithm and explore new routes to optimize their photovoltaic properties. A particular focus is set on the investigation of exciton and charge carrier loss phenomena and their dependence on the inter-monomeric interaction strength, chain architecture, and external mechanical loading. Our simulation results reveal that in the regime from low up to intermediate χ-parameters an increasing number of continuous percolation paths is created. In this parameter range, the internal quantum efficiency (IQE) increases up to a maximum, characterized by a minimum in the number of charge losses due to charge recombination. In the regime of high χ-parameters both block-copolymer systems form nanostructures with a large number of bottlenecks and dead ends. These lead to a large number of charge losses due to charge recombination, charge trapping, and a deteriorated exciton dissociation, resulting in a significant drop in the IQE. Moreover, we find that the photovoltaic performance of the triblock-copolymer material decreases with increasing mechanical loading, caused by a growing number of charge losses due to charge recombination and charge accumulation. Finally, we demonstrate that the process of charge trapping in defects can be reversed

  20. Piperlongumine selectively kills glioblastoma multiforme cells via reactive oxygen species accumulation dependent JNK and p38 activation.

    Science.gov (United States)

    Liu, Ju Mei; Pan, Feng; Li, Li; Liu, Qian Rong; Chen, Yong; Xiong, Xin Xin; Cheng, Kejun; Yu, Shang Bin; Shi, Zhi; Yu, Albert Cheung-Hoi; Chen, Xiao Qian

    2013-07-19

    Piperlongumine (PL), a natural alkaloid isolated from the long pepper, may have anti-cancer properties. It selectively targets and kills cancer cells but leaves normal cells intact. Here, we reported that PL selectively killed glioblastoma multiforme (GBM) cells via accumulating reactive oxygen species (ROS) to activate JNK and p38. PL at 20μM could induce severe cell death in three GBM cell lines (LN229, U87 and 8MG) but not astrocytes in cultures. PL elevated ROS prominently and reduced glutathione levels in LN229 and U87 cells. Antioxidant N-acetyl-L-cysteine (NAC) completely reversed PL-induced ROS accumulation and prevented cell death in LN229 and U87 cells. In LN229 and U87 cells, PL-treatment activated JNK and p38 but not Erk and Akt, in a dosage-dependent manner. These activations could be blocked by NAC pre-treatment. JNK and p38 specific inhibitors, SB203580 and SP600125 respectively, significantly blocked the cytotoxic effects of PL in LN229 and U87 cells. Our data first suggests that PL may have therapeutic potential for one of the most malignant and refractory tumors GBM. PMID:23796709

  1. The BTK Inhibitor Ibrutinib (PCI-32765) Blocks Hairy Cell Leukaemia Survival, Proliferation and BCR Signalling: A New Therapeutic Approach

    OpenAIRE

    Sivina, Mariela; Kreitman, Robert J.; Arons, Evgeny; Ravandi, Farhad; Burger, Jan A.

    2014-01-01

    B cell receptor (BCR) signalling plays a critical role in the progression of several B-cell malignancies, but its role in hairy cell leukaemia (HCL) is ambiguous. Bruton tyrosine kinase (BTK), a key player in BCR signalling, migration and adhesion, can be targeted with ibrutinib, a selective, irreversible BTK inhibitor. We analysed BTK expression and function in HCL and analysed the effects of ibrutinib on HCL cells. We demonstrated uniform BTK protein expression in HCL cells. Ibrutinib signi...

  2. PPAR-γ Activation Inhibits Angiogenesis by Blocking ELR+CXC Chemokine Production in Non-small Cell Lung Cancer

    Directory of Open Access Journals (Sweden)

    Venkateshwar G. Keshamouni

    2005-03-01

    Full Text Available Activation of peroxisome proliferator-activated receptor-γ (PPAR-γ results in inhibition of tumor growth in various types of cancers, but the mechanism(s by which PPAR-γ induces growth arrest has not been completely defined. In a recent study, we demonstrated that treatment of A549 (human non small cell lung cancer cell line tumor-bearing SCID mice with PPAR-γ ligands troglitazone (Tro and pioglitazone significantly inhibits primary tumor growth. In this study, immunohistochemical analysis of Tro-treated and Pio-treated tumors with factor VIII antibody revealed a significant reduction in blood vessel density compared to tumors in control animals, suggesting inhibition of angiogenesis. Further analysis showed that treatment of A549 cells in vitro with Tro or transient transfection of A549 cells with constitutively active PPAR-γ (VP16-PPAR-γ construct blocked the production of the angiogenic ELR +CXC chemokines IL-8 (CXCL8, ENA-78 (CXCL5, Gro-α (CXCL1. Similarly, an inhibitor of NF-ΚB activation (PDTC also blocked CXCL8, CXCL5, CXCL1 production, consistent with their NF-ΚB-dependent regulation. Conditioned media from A549 cells induce human microvascular endothelial cell (HMVEC chemotaxis. However, conditioned media from Tro-treated A549 cells induced significantly less HMVEC chemotaxis compared to untreated A549 cells. Furthermore, PPAR-γ activation inhibited NF-ΚB transcriptional activity, as assessed by TransAM reporter gene assay. Collectively, our data suggest that PPAR-γ ligands can inhibit tumor-associated angiogenesis by blocking the production of ELR+CXC chemokines, which is mediated through antagonizing NF-ΚB activation. These antiangiogenic effects likely contribute to the inhibition of primary tumor growth by PPAR-γ ligands.

  3. Expectancy bias in a selective conditioning procedure: trait anxiety increases the threat value of a blocked stimulus

    NARCIS (Netherlands)

    Y. Boddez; B. Vervliet; F. Baeyens; S. Lauwers; D. Hermans; T. Beckers

    2012-01-01

    Background and Objectives In a blocking procedure, a single conditioned stimulus (CS) is paired with an unconditioned stimulus (US), such as electric shock, in the first stage. During the subsequent stage, the CS is presented together with a second CS and this compound is followed by the same US. Fe

  4. Dynamin inhibitors induce caspase-mediated apoptosis following cytokinesis failure in human cancer cells and this is blocked by Bcl-2 overexpression

    Directory of Open Access Journals (Sweden)

    Braithwaite Antony W

    2011-06-01

    Full Text Available Abstract Background The aim of both classical (e.g. taxol and targeted anti-mitotic agents (e.g. Aurora kinase inhibitors is to disrupt the mitotic spindle. Such compounds are currently used in the clinic and/or are being tested in clinical trials for cancer treatment. We recently reported a new class of targeted anti-mitotic compounds that do not disrupt the mitotic spindle, but exclusively block completion of cytokinesis. This new class includes MiTMAB and OcTMAB (MiTMABs, which are potent inhibitors of the endocytic protein, dynamin. Like other anti-mitotics, MiTMABs are highly cytotoxic and possess anti-proliferative properties, which appear to be selective for cancer cells. The cellular response following cytokinesis failure and the mechanistic pathway involved is unknown. Results We show that MiTMABs induce cell death specifically following cytokinesis failure via the intrinsic apoptotic pathway. This involves cleavage of caspase-8, -9, -3 and PARP, DNA fragmentation and membrane blebbing. Apoptosis was blocked by the pan-caspase inhibitor, ZVAD, and in HeLa cells stably expressing the anti-apoptotic protein, Bcl-2. This resulted in an accumulation of polyploid cells. Caspases were not cleaved in MiTMAB-treated cells that did not enter mitosis. This is consistent with the model that apoptosis induced by MiTMABs occurs exclusively following cytokinesis failure. Cytokinesis failure induced by cytochalasin B also resulted in apoptosis, suggesting that disruption of this process is generally toxic to cells. Conclusion Collectively, these data indicate that MiTMAB-induced apoptosis is dependent on both polyploidization and specific intracellular signalling components. This suggests that dynamin and potentially other cytokinesis factors are novel targets for development of cancer therapeutics.

  5. Oncotripsy: Targeting cancer cells selectively via resonant harmonic excitation

    Science.gov (United States)

    Heyden, S.; Ortiz, M.

    2016-07-01

    We investigate a method of selectively targeting cancer cells by means of ultrasound harmonic excitation at their resonance frequency, which we refer to as oncotripsy. The geometric model of the cells takes into account the cytoplasm, nucleus and nucleolus, as well as the plasma membrane and nuclear envelope. Material properties are varied within a pathophysiologically-relevant range. A first modal analysis reveals the existence of a spectral gap between the natural frequencies and, most importantly, resonant growth rates of healthy and cancerous cells. The results of the modal analysis are verified by simulating the fully-nonlinear transient response of healthy and cancerous cells at resonance. The fully nonlinear analysis confirms that cancerous cells can be selectively taken to lysis by the application of carefully tuned ultrasound harmonic excitation while simultaneously leaving healthy cells intact.

  6. Oncotripsy: Targeting cancer cells selectively via resonant harmonic excitation

    CERN Document Server

    Heyden, Stefanie

    2015-01-01

    We investigate a method of selectively targeting cancer cells by means of ultrasound harmonic excitation at their resonance frequency, which we refer to as oncotripsy. The geometric model of the cells takes into account the cytoplasm, nucleus and nucleolus, as well as the plasma membrane and nuclear envelope. Material properties are varied within a pathophysiologically-relevant range. A first modal analysis reveals the existence of a spectral gap between the natural frequencies and, most importantly, resonant growth rates of healthy and cancerous cells. The results of the modal analysis are verified by simulating the fully-nonlinear transient response of healthy and cancerous cells at resonance. The fully nonlinear analysis confirms that cancerous cells can be selectively taken to lysis by the application of carefully tuned ultrasound harmonic excitation while simultaneously leaving healthy cells intact.

  7. Early activation of caspases during T lymphocyte stimulation results in selective substrate cleavage in nonapoptotic cells.

    Science.gov (United States)

    Alam, A; Cohen, L Y; Aouad, S; Sékaly, R P

    1999-12-20

    Apoptosis induced by T cell receptor (TCR) triggering in T lymphocytes involves activation of cysteine proteases of the caspase family through their proteolytic processing. Caspase-3 cleavage was also reported during T cell stimulation in the absence of apoptosis, although the physiological relevance of this response remains unclear. We show here that the caspase inhibitor benzyloxycarbonyl (Cbz)-Val-Ala-Asp(OMe)-fluoromethylketone (zVAD) blocks proliferation, major histocompatibility complex class II expression, and blastic transformation during stimulation of peripheral blood lymphocytes. Moreover, T cell activation triggers the selective processing and activation of downstream caspases (caspase-3, -6, and -7), but not caspase-1, -2, or -4, as demonstrated even in intact cells using a cell-permeable fluorescent substrate. Caspase-3 processing occurs in different T cell subsets (CD4(+), CD8(+), CD45RA(+), and CD45RO(+)), and in activated B lymphocytes. The pathway leading to caspase activation involves death receptors and caspase-8, which is also processed after TCR triggering, but not caspase-9, which remains as a proenzyme. Most importantly, caspase activity results in a selective substrate specificity, since poly(ADP-ribose) polymerase (PARP), lamin B, and Wee1 kinase, but not DNA fragmentation factor (DFF45) or replication factor C (RFC140), are processed. Caspase and substrate processing occur in nonapoptotic lymphocytes. Thus, caspase activation is an early and physiological response in viable, stimulated lymphocytes, and appears to be involved in early steps of lymphocyte activation. PMID:10601362

  8. Selective radiolabeling of cell surface proteins to a high specific activity

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, J.A.; Lau, A.L.; Cunningham, D.D.

    1987-02-10

    A procedure was developed for selective radiolabeling of membrane proteins on cells to higher specific activities than possible with available techniques. Cell surface amino groups were derivatized with /sup 125/I-(hydroxyphenyl)propionyl groups via /sup 125/I-sulfosuccinimidyl (hydroxyphenyl)propionate (/sup 125/II-sulfo-SHPP). This reagent preferentially labeled membrane proteins exposed at the cell surface of erythrocytes as assessed by the degree of radiolabel incorporation into erythrocyte ghost proteins and hemoglobin. Comparison with the lactoperoxidase-(/sup 125/I)iodide labeling technique revealed that /sup 125/I-sulfo-SHPP labeled cell surface proteins to a much higher specific activity and hemoglobin to a much lower specific activity. Additionally, this reagent was used for selective radiolabeling of membrane proteins on the cytoplasmic face of the plasma membrane by blocking exofacial amino groups with uniodinated sulfo-SHPP, lysing the cells, and then incubating them with /sup 125/I-sulfo-SHPP. Exclusive labeling of either side of the plasma membrane was demonstrated by the labeling of some marker proteins with well-defined spacial orientations on erythroctyes. Transmembrane proteins such as the epidermal growth factor receptor on cultured cells could also be labeled differentially from either side of the plasma membrane.

  9. Selective toxicity of rhodamine 123 in carcinoma cells in vitro.

    Science.gov (United States)

    Lampidis, T J; Bernal, S D; Summerhayes, I C; Chen, L B

    1983-02-01

    The study of mitochondria in situ has recently been facilitated through the use of rhodamine 123, a mitochondrial-specific fluorescent dye. It has been found to be nontoxic when applied for short periods to a variety of cell types and has thus become an invaluable tool for examining mitochondrial morphology and function in the intact living cell. In this report, however, we demonstrate that with continuous exposure, rhodamine 123 selectively kills carcinoma as compared to normal epithelial cells grown in vitro. At doses of rhodamine 123 which were toxic to carcinoma cells, the conversion of mitochondrial-specific to cytoplasmic-nonspecific localization of the drug was observed prior to cell death. At 10 microgram/ml, greater than 50% cell death occurred within 7 days in all nine of the carcinoma cell types and lines of different origin studied, while six of six normal epithelial cell types and lines remained unaffected. Cotreating carcinoma cells with 2-deoxyglucose and rhodamine 123 enhanced the inhibition of growth by rhodamine 123 alone in clonogenic survival assays. The observation of the selective toxicity of rhodamine 123 appears to be unique in view of the absence of selective toxicity reported in vitro for the various antitumor agents currently in clinical use. Preliminary results with rhodamine 123 in animal tumor systems indicate antitumor activity for carcinomas.

  10. Morphology And Local Mechanical Properties Of A Block Copolymer Cell Substrate

    Science.gov (United States)

    Wall, Craig; Yermolenko, Ivan; Krishnan, G. Rajesh; Sarkar, Debanjan; Alexander, John

    2014-03-01

    Atomic force microscopy (AFM) was applied for the characterization of morphology and mechanical properties of a block copolymer coating designed for biomaterials applications. The material is a block-copolymer with poly(ethylene glycol) as one block and a peptide as second block, which are connected through urethane bonds. The AFM images obtained in amplitude modulation mode revealed the morphology is characterized by micron-scale sheaf-like structures embedded in a more homogeneous and, presumably, amorphous matrix. The self-assembly of the peptide segments is responsible for the formation of the ordered sheaf structures and this phenomenon was common for different variations of the components. Maps of elastic modulus and work of adhesion of the block copolymer, which also differentiate the matrix and ordered regions, were obtained with Hybrid mode at different tip-force levels. The quantitative estimates show that elastic modulus varies in the MPa range and work of adhesion in the hundreds of mJ/m2 range. These data are compared with AFM-based nanoindentation that was performed at higher tip-force level. The results indicate that material surface is more complicated and they suggest in-depth morphology variations. A tentative model of the structural organization is proposed.

  11. Double Fertilization in Arabidopsis thaliana Involves a Polyspermy Block on the Egg but Not the Central Cell

    Institute of Scientific and Technical Information of China (English)

    Rod J.Scott; Susan J.Armstrong; James Doughty; Melissa Spielman

    2008-01-01

    In animal reproduction,thousands of sperm may compete to fertilize a single egg,but polyspermy blocks prevent multiple fertilization that would otherwise lead to death of the embryo.In flowering plants,successfuI seed development requires that only two sperm are delivered to the embryo sac,where each must fertilize a female gamete(egg or central cell)to produce the embryo and endosperm.Therefore,polyspermy must be avoided,not only to prevent abnormalities in offspring,but to ensure double fertilization.It is not understood how each sperm fertilizes only one female gamete,nor has the existence of polyspermy barriers been directly tested in vivo.Here,we sought evidence for poly-spermy blocks in angiosperms using the polyspermic tetraspore(tes)mutant of Arabidopsis,which allows in-vivo challenge of egg and central cell with multiple male gametes.We show that tes mutant pollen tubes can transmit more than one sperm pair to an embryo sac,and that sperm from more than one pair can participate in fertilization.We detected endosperms but not embryos with ploidies that could only result from multiple fertilization.Our results therefore dem-onstrate an in-vivo polyspermy block on the egg,but not the central cell of a flowering plant.

  12. Activation of the canonical Wnt pathway leads to loss of hematopoietic stem cell repopulation and multilineage differentiation block

    DEFF Research Database (Denmark)

    Kirstetter, Peggy; Anderson, Kristina; Porse, Bo T;

    2006-01-01

    of hematopoietic stem cell function was associated with decreased expression of Cdkn1a (encoding the cell cycle inhibitor p21(cdk)), Sfpi1, Hoxb4 and Bmi1 (encoding the transcription factors PU.1, HoxB4 and Bmi-1, respectively) and altered integrin expression in Lin(-)Sca-1(+)c-Kit(+) cells, whereas PU.1......Wnt signaling increases hematopoietic stem cell self-renewal and is activated in both myeloid and lymphoid malignancies, indicating involvement in both normal and malignant hematopoiesis. We report here activated canonical Wnt signaling in the hematopoietic system through conditional expression...... of a stable form of beta-catenin. This enforced expression led to hematopoietic failure associated with loss of myeloid lineage commitment at the granulocyte-macrophage progenitor stage; blocked erythrocyte differentiation; disruption of lymphoid development; and loss of repopulating stem cell activity. Loss...

  13. Blocking the NOTCH pathway can inhibit the growth of CD133-positive A549 cells and sensitize to chemotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Juntao; Mao, Zhangfan; Huang, Jie; Xie, Songping; Liu, Tianshu; Mao, Zhifu, E-mail: 48151660@qq.com

    2014-02-21

    Highlights: • Notch signaling pathway members are expressed lower levels in CD133+ cells. • CD133+ cells are not as sensitive as CD133− cells to chemotherapy. • GSI could inhibit the growth of both CD133+ and CD133− cells. • Blockade of Notch signaling pathway enhanced the effect of chemotherapy with CDDP. • DAPT/CDDP co-therapy caused G2/M arrest and elimination in CD133+ cells. - Abstract: Cancer stem cells (CSCs) are believed to play an important role in tumor growth and recurrence. These cells exhibit self-renewal and proliferation properties. CSCs also exhibit significant drug resistance compared with normal tumor cells. Finding new treatments that target CSCs could significantly enhance the effect of chemotherapy and improve patient survival. Notch signaling is known to regulate the development of the lungs by controlling the cell-fate determination of normal stem cells. In this study, we isolated CSCs from the human lung adenocarcinoma cell line A549. CD133 was used as a stem cell marker for fluorescence-activated cell sorting (FACS). We compared the expression of Notch signaling in both CD133+ and CD133− cells and blocked Notch signaling using the γ-secretase inhibitor DAPT (GSI-IX). The effect of combining GSI and cisplatin (CDDP) was also examined in these two types of cells. We observed that both CD133+ and CD133− cells proliferated at similar rates, but the cells exhibited distinctive differences in cell cycle progression. Few CD133+ cells were observed in the G{sub 2}/M phase, and there were half as many cells in S phase compared with the CD133− cells. Furthermore, CD133+ cells exhibited significant resistance to chemotherapy when treated with CDDP. The expression of Notch signaling pathway members, such as Notch1, Notch2 and Hes1, was lower in CD133+ cells. GSI slightly inhibited the proliferation of both cell types and exhibited little effect on the cell cycle. The inhibitory effects of DPP on these two types of cells were

  14. Blocking the NOTCH pathway can inhibit the growth of CD133-positive A549 cells and sensitize to chemotherapy

    International Nuclear Information System (INIS)

    Highlights: • Notch signaling pathway members are expressed lower levels in CD133+ cells. • CD133+ cells are not as sensitive as CD133− cells to chemotherapy. • GSI could inhibit the growth of both CD133+ and CD133− cells. • Blockade of Notch signaling pathway enhanced the effect of chemotherapy with CDDP. • DAPT/CDDP co-therapy caused G2/M arrest and elimination in CD133+ cells. - Abstract: Cancer stem cells (CSCs) are believed to play an important role in tumor growth and recurrence. These cells exhibit self-renewal and proliferation properties. CSCs also exhibit significant drug resistance compared with normal tumor cells. Finding new treatments that target CSCs could significantly enhance the effect of chemotherapy and improve patient survival. Notch signaling is known to regulate the development of the lungs by controlling the cell-fate determination of normal stem cells. In this study, we isolated CSCs from the human lung adenocarcinoma cell line A549. CD133 was used as a stem cell marker for fluorescence-activated cell sorting (FACS). We compared the expression of Notch signaling in both CD133+ and CD133− cells and blocked Notch signaling using the γ-secretase inhibitor DAPT (GSI-IX). The effect of combining GSI and cisplatin (CDDP) was also examined in these two types of cells. We observed that both CD133+ and CD133− cells proliferated at similar rates, but the cells exhibited distinctive differences in cell cycle progression. Few CD133+ cells were observed in the G2/M phase, and there were half as many cells in S phase compared with the CD133− cells. Furthermore, CD133+ cells exhibited significant resistance to chemotherapy when treated with CDDP. The expression of Notch signaling pathway members, such as Notch1, Notch2 and Hes1, was lower in CD133+ cells. GSI slightly inhibited the proliferation of both cell types and exhibited little effect on the cell cycle. The inhibitory effects of DPP on these two types of cells were enhanced

  15. Adipose-derived stem cells: selecting for translational success.

    Science.gov (United States)

    Johal, Kavan S; Lees, Vivien C; Reid, Adam J

    2015-01-01

    We have witnessed a rapid expansion of in vitro characterization and differentiation of adipose-derived stem cells, with increasing translation to both in vivo models and a breadth of clinical specialties. However, an appreciation of the truly heterogeneous nature of this unique stem cell group has identified a need to more accurately delineate subpopulations by any of a host of methods, to include functional properties or surface marker expression. Cells selected for improved proliferative, differentiative, angiogenic or ischemia-resistant properties are but a few attributes that could prove beneficial for targeted treatments or therapies. Optimizing cell culture conditions to permit re-introduction to patients is critical for clinical translation.

  16. A novel anti-EMMPRIN function-blocking antibody reduces T cell proliferation and neurotoxicity: relevance to multiple sclerosis

    Directory of Open Access Journals (Sweden)

    Agrawal Smriti M

    2012-04-01

    Full Text Available Abstract Background Extracellular matrix metalloproteinase inducer (EMMPRIN; CD147, basigin is an inducer of the expression of several matrix metalloproteinases (MMPs. We reported previously that blocking EMMPRIN activity reduced neuroinflammation and severity of disease in an animal model of multiple sclerosis (MS, experimental autoimmune encephalomyelitis (EAE. Methods To improve upon EMMPRIN blockade, and to help unravel the biological functions of EMMPRIN in inflammatory disorders, we have developed several anti-EMMPRIN monoclonal antibodies. Results Of these monoclonal antibodies, a particular one, clone 10, was efficient in binding mouse and human cells using several methods of detection. The specificity of clone 10 was demonstrated by its lack of staining of EMMPRIN-null embryos compared to heterozygous and wild-type mouse samples. Functionally, human T cells activated with anti-CD3 and anti-CD28 elevated their expression of EMMPRIN and the treatment of these T cells with clone 10 resulted in decreased proliferation and matrix metalloproteinase- 9 (MMP-9 production. Activated human T cells were toxic to human neurons in culture and clone 10 pretreatment reduced T cell cytotoxicity correspondent with decrease of granzyme B levels within T cells. In vivo, EAE mice treated with clone 10 had a markedly reduced disease score compared to mice treated with IgM isotype control. Conclusions We have produced a novel anti-EMMPRIN monoclonal antibody that blocks several aspects of T cell activity, thus highlighting the multiple roles of EMMPRIN in T cell biology. Moreover, clone 10 reduces EAE scores in mice compared to controls, and has activity on human cells, potentially allowing for the testing of anti-EMMPRIN treatment not only in EAE, but conceivably also in MS.

  17. Hair cell recovery in mitotically blocked cultures of the bullfrog saccule

    OpenAIRE

    Baird, Richard A.; Burton, Miriam D.; Fashena, David S.; Naeger, Rebecca A.

    2000-01-01

    Hair cells in many nonmammalian vertebrates are regenerated by the mitotic division of supporting cell progenitors and the differentiation of the resulting progeny into new hair cells and supporting cells. Recent studies have shown that nonmitotic hair cell recovery after aminoglycoside-induced damage can also occur in the vestibular organs. Using hair cell and supporting cell immunocytochemical markers, we have used confocal and electron microscopy to examine the fate...

  18. Recovery of DNA synthesis after ultraviolet irradiation of xeroderma pigmentosum cells depends on excision repair and is blocked by caffeine

    International Nuclear Information System (INIS)

    Normal human and xeroderma pigmentosum (XP, excision-defective group A) cells (both SV40-transformed) pulse-labeled with [3H] thymidine at various times after irradiation with ultraviolet light showed a decline and recovery of both the molecular weights of newly synthesized DNA and the rated of synthesis per cell. At the same ultraviolet dose, both molecular weights and rates of synthesis were inhibited more in XP than in normal cells. This indicates that excision repair plays a role in minimizing the inhibition of chain growth, possibly by excision of dimers ahead of the growing point. The ability to synthesize normal-sized DNA recovered more rapidly than rates of synthesis in normal cells, but both parameters recovered in phase in XP cells. During recovery in normal cells there are therefore fewer actively replicating clusters of replicons because the single-strand breaks involved in the excision of dimers inhibit replicon initiation. XP cells have few excision repair events and therefore fewer breaks to interfere with initiation, but chain growth is blocked by unexcised dimers. In both cell types recovery of the ability to synthesize normal-sized DNA was prevented by growing cells in caffeine after irradiation, possibly because of competition between the DNA binding properties of caffeine and replication proteins. These observations imply that excision repair and semiconservative replication interact strongly in irradiated cells to produce a complex spectrum of changes in DNA replication which may be confused with parts of alternative systems such as post-replication repair. (author)

  19. A fungal metabolite asperparaline a strongly and selectively blocks insect nicotinic acetylcholine receptors: the first report on the mode of action.

    Directory of Open Access Journals (Sweden)

    Koichi Hirata

    Full Text Available Asperparalines produced by Aspergillus japonicus JV-23 induce paralysis in silkworm (Bombyx mori larvae, but the target underlying insect toxicity remains unknown. In the present study, we have investigated the actions of asperparaline A on ligand-gated ion channels expressed in cultured larval brain neurons of the silkworm using patch-clamp electrophysiology. Bath-application of asperparaline A (10 µM had no effect on the membrane current, but when delivered for 1 min prior to co-application with 10 µM acetylcholine (ACh, it blocked completely the ACh-induced current that was sensitive to mecamylamine, a nicotinic acetylcholine receptor (nAChR-selective antaogonist. In contrast, 10 µM asperparaline A was ineffective on the γ-aminobutyric acid- and L-glutamate-induced responses of the Bombyx larval neurons. The fungal alkaloid showed no-use dependency in blocking the ACh-induced response with distinct affinity for the peak and slowly-desensitizing current amplitudes of the response to 10 µM ACh in terms of IC(50 values of 20.2 and 39.6 nM, respectively. Asperparaline A (100 nM reduced the maximum neuron response to ACh with a minimal shift in EC(50, suggesting that the alkaloid is non-competitive with ACh. In contrast to showing marked blocking action on the insect nAChRs, it exhibited only a weak blocking action on chicken α3β4, α4β2 and α7 nAChRs expressed in Xenopus laevis oocytes, suggesting a high selectivity for insect over certain vertebrate nAChRs.

  20. Cuprous oxide nanoparticles selectively induce apoptosis of tumor cells

    Directory of Open Access Journals (Sweden)

    Wang Y

    2012-05-01

    Full Text Available Ye Wang,1,2,* Xiao-Yuan Zi,1,* Juan Su,1 Hong-Xia Zhang,1 Xin-Rong Zhang,3 Hai-Ying Zhu,1 Jian-Xiu Li,1 Meng Yin,3 Feng Yang,3 Yi-Ping Hu,11Department of Cell Biology, 2School of Clinical Medicine, 3Department of Pharmaceuticals, Second Military Medical University, Shanghai, People's Republic of China*Authors contributed equally.Abstract: In the rapid development of nanoscience and nanotechnology, many researchers have discovered that metal oxide nanoparticles have very useful pharmacological effects. Cuprous oxide nanoparticles (CONPs can selectively induce apoptosis and suppress the proliferation of tumor cells, showing great potential as a clinical cancer therapy. Treatment with CONPs caused a G1/G0 cell cycle arrest in tumor cells. Furthermore, CONPs enclosed in vesicles entered, or were taken up by mitochondria, which damaged their membranes, thereby inducing apoptosis. CONPs can also produce reactive oxygen species (ROS and initiate lipid peroxidation of the liposomal membrane, thereby regulating many signaling pathways and influencing the vital movements of cells. Our results demonstrate that CONPs have selective cytotoxicity towards tumor cells, and indicate that CONPs might be a potential nanomedicine for cancer therapy.Keywords: nanomedicine, selective cytotoxicity, apoptosis, cell cycle arrest, mitochondrion-targeted nanomaterials

  1. Enhanced in vitro selective toxicity of chemotherapeutic agents for human cancer cells based on a metabolic defect.

    Science.gov (United States)

    Stern, P H; Hoffman, R M

    1986-04-01

    A metabolic defect that is prevalent in human cancer cell lines was exploited to selectively kill these cells without killing cocultured normal human fibroblasts. Methionine dependence, a metabolic defect seen only in cancer cells or immortalized cell lines in vitro, precludes the cells from growing in media in which methionine is replaced by its immediate precursor, homocysteine, a condition that allows the growth of all normal cell strains tested. The methionine-dependent cells become reversibly blocked in late S-G2 (i.e., late-S and G2 phases) under the above condition, a block that was exploited for selective chemotherapy against these cells. In cultures that were initiated with equal amounts of cancer cells and human diploid fibroblasts, substitution of homocysteine and doxorubicin for methionine in the culture medium followed by methionine repletion with vincristine was totally effective at selectively eliminating a methionine-dependent human sarcoma and 3 methionine-dependent human carcinomas. The above protocol was nearly totally effective against a partially methionine-independent revertant of the sarcoma. The chemotherapeutic procedure used was not lethal to normal cells growing alongside the tumor cells and was ineffective when conducted totally in methionine-containing medium. The optimal procedure was 10(-10) M doxorubicin in methionine-free, homocysteine-containing medium for 10 days followed by 2 x 10(-7) M vincristine in methionine-containing, homocysteine-free medium for 1 day, in turn followed by drug-free methionine-containing, homocysteine-free medium. These results demonstrate the potential for treatment of solid tumors with chemotherapy based on metabolic differences between normal and tumor cells.

  2. Glucocorticoids and histone deacetylase inhibitors cooperate to block the invasiveness of basal-like breast cancer cells through novel mechanisms

    DEFF Research Database (Denmark)

    Law, M E; Corsino, P E; Jahn, S C;

    2013-01-01

    cells are a frequently used model of invasive triple-negative breast cancer, and these cells express low levels of E-cadherin that is mislocalized to cytoplasmic vesicles. MDA-MB-231 cell lines stably expressing wild-type E-cadherin or E-cadherin fused to glutathione S-transferase or green fluorescent...... protein were used as experimental systems to probe the mechanisms responsible for cytoplasmic E-cadherin localization in invasive cancers. Although E-cadherin expression partly reduced cell invasion in vitro, E-cadherin was largely localized to the cytoplasm and did not block the invasiveness......Aggressive cancers often express E-cadherin in cytoplasmic vesicles rather than on the plasma membrane and this may contribute to the invasive phenotype of these tumors. Therapeutic strategies are not currently available that restore the anti-invasive function of E-cadherin in cancers. MDA-MB-231...

  3. Suppression of intratumoral CCL22 by type i interferon inhibits migration of regulatory T cells and blocks cancer progression.

    Science.gov (United States)

    Anz, David; Rapp, Moritz; Eiber, Stephan; Koelzer, Viktor H; Thaler, Raffael; Haubner, Sascha; Knott, Max; Nagel, Sarah; Golic, Michaela; Wiedemann, Gabriela M; Bauernfeind, Franz; Wurzenberger, Cornelia; Hornung, Veit; Scholz, Christoph; Mayr, Doris; Rothenfusser, Simon; Endres, Stefan; Bourquin, Carole

    2015-11-01

    The chemokine CCL22 is abundantly expressed in many types of cancer and is instrumental for intratumoral recruitment of regulatory T cells (Treg), an important subset of immunosuppressive and tumor-promoting lymphocytes. In this study, we offer evidence for a generalized strategy to blunt Treg activity that can limit immune escape and promote tumor rejection. Activation of innate immunity with Toll-like receptor (TLR) or RIG-I-like receptor (RLR) ligands prevented accumulation of Treg in tumors by blocking their immigration. Mechanistic investigations indicated that Treg blockade was a consequence of reduced intratumoral CCL22 levels caused by type I IFN. Notably, stable expression of CCL22 abrogated the antitumor effects of treatment with RLR or TLR ligands. Taken together, our findings argue that type I IFN blocks the Treg-attracting chemokine CCL22 and thus helps limit the recruitment of Treg to tumors, a finding with implications for cancer immunotherapy. PMID:26432403

  4. miR-150, a microRNA expressed in mature B and T cells, blocks early B cell development when expressed prematurely.

    Science.gov (United States)

    Zhou, Beiyan; Wang, Stephanie; Mayr, Christine; Bartel, David P; Lodish, Harvey F

    2007-04-24

    MicroRNAs (miRNAs) are a family of approximately 22-nt noncoding RNAs that can posttranscriptionally regulate gene expression. Several miRNAs are specifically expressed in hematopoietic cells. Here we show that one such miRNA, miR-150, is mainly expressed in the lymph nodes and spleen and is highly up-regulated during the development of mature T and B cells; expression of miR-150 is sharply up-regulated at the immature B cell stage. Overexpression of miR-150 in hematopoietic stem cells, followed by bone marrow transplantation, had little effect on the formation of either mature CD8- and CD4-positive T cells or granulocytes or macrophages, but the formation of mature B cells was greatly impaired. Furthermore, premature expression of miR-150 blocked the transition from the pro-B to the pre-B stage. Our results indicate that miR-150 most likely down-regulates mRNAs that are important for pre- and pro-B cell formation or function, and its ectopic expression in these cells blocks further development of B cells.

  5. Selective Cell Targeting with Light-Absorbing Microparticles and Nanoparticles

    OpenAIRE

    Pitsillides, Costas M; Joe, Edwin K.; Wei, Xunbin; Anderson, R. Rox; Lin, Charles P.

    2003-01-01

    We describe a new method for selective cell targeting based on the use of light-absorbing microparticles and nanoparticles that are heated by short laser pulses to create highly localized cell damage. The method is closely related to chromophore-assisted laser inactivation and photodynamic therapy, but is driven solely by light absorption, without the need for photochemical intermediates (particularly singlet oxygen). The mechanism of light-particle interaction was investigated by nanosecond ...

  6. Cold atmospheric plasma for selectively ablating metastatic breast cancer cells.

    Science.gov (United States)

    Wang, Mian; Holmes, Benjamin; Cheng, Xiaoqian; Zhu, Wei; Keidar, Michael; Zhang, Lijie Grace

    2013-01-01

    Traditional breast cancer treatments such as surgery and radiotherapy contain many inherent limitations with regards to incomplete and nonselective tumor ablation. Cold atmospheric plasma (CAP) is an ionized gas where the ion temperature is close to room temperature. It contains electrons, charged particles, radicals, various excited molecules, UV photons and transient electric fields. These various compositional elements have the potential to either enhance and promote cellular activity, or disrupt and destroy them. In particular, based on this unique composition, CAP could offer a minimally-invasive surgical approach allowing for specific cancer cell or tumor tissue removal without influencing healthy cells. Thus, the objective of this research is to investigate a novel CAP-based therapy for selectively bone metastatic breast cancer treatment. For this purpose, human metastatic breast cancer (BrCa) cells and bone marrow derived human mesenchymal stem cells (MSCs) were separately treated with CAP, and behavioral changes were evaluated after 1, 3, and 5 days of culture. With different treatment times, different BrCa and MSC cell responses were observed. Our results showed that BrCa cells were more sensitive to these CAP treatments than MSCs under plasma dose conditions tested. It demonstrated that CAP can selectively ablate metastatic BrCa cells in vitro without damaging healthy MSCs at the metastatic bone site. In addition, our study showed that CAP treatment can significantly inhibit the migration and invasion of BrCa cells. The results suggest the great potential of CAP for breast cancer therapy.

  7. Cold atmospheric plasma for selectively ablating metastatic breast cancer cells.

    Directory of Open Access Journals (Sweden)

    Mian Wang

    Full Text Available Traditional breast cancer treatments such as surgery and radiotherapy contain many inherent limitations with regards to incomplete and nonselective tumor ablation. Cold atmospheric plasma (CAP is an ionized gas where the ion temperature is close to room temperature. It contains electrons, charged particles, radicals, various excited molecules, UV photons and transient electric fields. These various compositional elements have the potential to either enhance and promote cellular activity, or disrupt and destroy them. In particular, based on this unique composition, CAP could offer a minimally-invasive surgical approach allowing for specific cancer cell or tumor tissue removal without influencing healthy cells. Thus, the objective of this research is to investigate a novel CAP-based therapy for selectively bone metastatic breast cancer treatment. For this purpose, human metastatic breast cancer (BrCa cells and bone marrow derived human mesenchymal stem cells (MSCs were separately treated with CAP, and behavioral changes were evaluated after 1, 3, and 5 days of culture. With different treatment times, different BrCa and MSC cell responses were observed. Our results showed that BrCa cells were more sensitive to these CAP treatments than MSCs under plasma dose conditions tested. It demonstrated that CAP can selectively ablate metastatic BrCa cells in vitro without damaging healthy MSCs at the metastatic bone site. In addition, our study showed that CAP treatment can significantly inhibit the migration and invasion of BrCa cells. The results suggest the great potential of CAP for breast cancer therapy.

  8. Intrinsic Folding Proclivities in Cyclic β-Peptide Building Blocks: Configuration and Heteroatom Effects Analyzed by Conformer-Selective Spectroscopy and Quantum Chemistry.

    Science.gov (United States)

    Alauddin, Mohammad; Gloaguen, Eric; Brenner, Valérie; Tardivel, Benjamin; Mons, Michel; Zehnacker-Rentien, Anne; Declerck, Valérie; Aitken, David J

    2015-11-01

    This work describes the use of conformer-selective laser spectroscopy following supersonic expansion to probe the local folding proclivities of four-membered ring cyclic β-amino acid building blocks. Emphasis is placed on stereochemical effects as well as on the structural changes induced by the replacement of a carbon atom of the cycle by a nitrogen atom. The amide A IR spectra are obtained and interpreted with the help of quantum chemistry structure calculations. Results provide evidence that the building block with a trans-substituted cyclobutane ring has a predilection to form strong C8 hydrogen bonds. Nitrogen-atom substitution in the ring induces the formation of the hydrazino turn, with a related but distinct hydrogen-bonding network: the structure is best viewed as a bifurcated C8/C5 bond with the N heteroatom lone electron pair playing a significant acceptor role, which supports recent observations on the hydrazino turn structure in solution. Surprisingly, this study shows that the cis-substituted cyclobutane ring derivative also gives rise predominantly to a C8 hydrogen bond, although weaker than in the two former cases, a feature that is not often encountered for this building block.

  9. Population diversity and antibody selective pressure to Plasmodium falciparum MSP1 block2 locus in an African malaria-endemic setting

    Directory of Open Access Journals (Sweden)

    Trape Jean-François

    2009-10-01

    Full Text Available Abstract Background Genetic evidence for diversifying selection identified the Merozoite Surface Protein1 block2 (PfMSP1 block2 as a putative target of protective immunity against Plasmodium falciparum. The locus displays three family types and one recombinant type, each with multiple allelic forms differing by single nucleotide polymorphism as well as sequence, copy number and arrangement variation of three amino acid repeats. The family-specific antibody responses observed in endemic settings support immune selection operating at the family level. However, the factors contributing to the large intra-family allelic diversity remain unclear. To address this question, population allelic polymorphism and sequence variant-specific antibody responses were studied in a single Senegalese rural community where malaria transmission is intense and perennial. Results Family distribution showed no significant temporal fluctuation over the 10 y period surveyed. Sequencing of 358 PCR fragments identified 126 distinct alleles, including numerous novel alleles in each family and multiple novel alleles of recombinant types. The parasite population consisted in a large number of low frequency alleles, alongside one high-frequency and three intermediate frequency alleles. Population diversity tests supported positive selection at the family level, but showed no significant departure from neutrality when considering intra-family allelic sequence diversity and all families combined. Seroprevalence, analysed using biotinylated peptides displaying numerous sequence variants, was moderate and increased with age. Reactivity profiles were individual-specific, mapped to the family-specific flanking regions and to repeat sequences shared by numerous allelic forms within a family type. Seroreactivity to K1-, Mad20- and R033 families correlated with the relative family genotype distribution within the village. Antibody specificity remained unchanged with cumulated exposure

  10. Nimotuzumab enhances radiation sensitivity of NSCLC H292 cells in vitro by blocking epidermal growth factor receptor nuclear translocation and inhibiting radiation-induced DNA damage repair

    Directory of Open Access Journals (Sweden)

    Teng K

    2015-04-01

    Full Text Available Kai Teng,1,2,* Yong Zhang,1,* Xiaoyan Hu,1 Yihui Ding,1 Rui Gong,1 Li Liu1,* 1Department of Thoracic Oncology, Cancer Center of Wuhan Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, People’s Republic of China; 2Department of Radiation Oncology, Hainan Cancer Hospital, Haikou, Hainan, People’s Republic of China *These authors contributed equally to this work Background: The epidermal growth factor receptor (EGFR signaling pathway plays a significant role in radiation resistance. There is evidence that EGFR nuclear translocation is associated with DNA double-strand breaks (DSB repair. Nimotuzumab has shown the effect of radiosensitization in various cancer cells, but little is known about the relationship between nimotuzumab and EGFR nuclear translocation in non-small cell lung cancer (NSCLC cell lines. In this study, we selected two NSCLC cell lines, namely, H292 (with high EGFR expression and H1975 (with low EGFR expression and explored the mechanisms underlying radiation sensitivity.Methods: MTT assay, clonogenic survival assay, and flow cytometry were performed separately to test cell viability, radiation sensitivity, cell cycle distribution, and apoptosis. Protein γ-H2AX, DNA-PK/p-DNA-PK, and EGFR/p-EGFR expression were further compared both in the cytoplasm and the nucleus with the western blot.Results: Nimotuzumab reduced the viability of H292 cells and sensitized H292 cells to ionizing radiation. The radiation sensitivity enhancement ratio (SER was 1.304 and 1.092 for H292 and H1975 cells, respectively. H292 cells after nimotuzumab administration were arrested at the G0/G1 phase in response to radiation. Apoptosis was without statistical significance in both cell lines. γ-H2AX formation in the combination group (nimotuzumab and radiation increased both in the cytoplasm and the nucleus along with the decreased expression of nuclear EGFR/p-EGFR and p-DNA-PK in H292 cells (P<0.05 that

  11. 19.2% Efficient InP Heterojunction Solar Cell with Electron-Selective TiO2 Contact

    OpenAIRE

    Yin, Xingtian; Battaglia, Corsin; Lin, Yongjing; Chen, Kevin; Hettick, Mark; Zheng, Maxwell; Chen, Cheng-Ying; Kiriya, Daisuke; Javey, Ali

    2014-01-01

    We demonstrate an InP heterojunction solar cell employing an ultrathin layer (∼10 nm) of amorphous TiO2 deposited at 120 °C by atomic layer deposition as the transparent electron-selective contact. The TiO2 film selectively extracts minority electrons from the conduction band of p-type InP while blocking the majority holes due to the large valence band offset, enabling a high maximum open-circuit voltage of 785 mV. A hydrogen plasma treatment of the InP surface drastically improves the long-w...

  12. Physics of sinking and selection of plankton cell size

    Energy Technology Data Exchange (ETDEWEB)

    Sciascia, R., E-mail: r.sciascia@isac.cnr.it [Institute of Atmospheric Sciences and Climate, CNR, Corso Fiume, 4, 10133 Torino (Italy); Doctorate Program in Fluid Dynamics, Politecnico di Torino (Italy); De Monte, S. [CNRS, UMR 7625 “Ecologie et Evolution”, Paris, F-75005 (France); Université Pierre et Marie Curie-Paris 6, UMR 7625 “Ecologie et Evolution”, Paris, F-75005 (France); Institut de Biologie de l' Ecole Normale Supérieure, UMR 7625 “Ecologie et Evolution”, Paris, F-75005 (France); Provenzale, A. [Institute of Atmospheric Sciences and Climate, CNR, Corso Fiume, 4, 10133 Torino (Italy)

    2013-02-04

    Gravitational sinking in the water column is known to affect size composition of planktonic communities. One important driver toward the reduction of plankton size is the fact that larger cells tend to sink faster below the euphotic layer. In this work, we discuss the role of gravitational sinking in driving cell size selection, showing that the outcome of phytoplankton competition is determined by the dependence of sinking velocity on cell size, shape, and on the temporal variability associated with turbulence. This opens a question on whether regional modulations of the turbulence intensity could affect size distribution of planktonic communities.

  13. EVALUATION OF ASHA PROGRAMME IN SELECTED BLOCK OF RAISEN DISTRICT OF MADHYA PRADESH UNDER THE NATIONAL RURAL HEALTH MISSION

    Directory of Open Access Journals (Sweden)

    Bhagwan

    2014-01-01

    Full Text Available Currently Government of India is providing comprehensive integrated health care to the rural people under the umbrella of National Rural Health Mission (NRHM. A village level community health worker “Accredited Social Health Activist” (ASHA’ acts as an interface between the community and the public health system. OBJECTIVE : To assess the socio - demographic profile of ASHA workers and to evaluate their knowledge and practice of their responsibilities. SETTINGS & DESIGN : Cross - sectional study , Obedullaganj and Sa n chi blocks of Bhopal district of Madhya Pradesh . METHODS & MATERIAL: A cross - sectional study was conducted at obedullaganj and Sanchi in the Bhopal district of Madhya Pradesh for a period of 1 year from October 2007 to October 2008 The study participa nts were trained ASHA workers working in the Sanchi & Obedullaganj block. Statistical Analysis : Chi Square test using MS excel & SPSS ver 17. RESULT : Majority of ASHA workers were aware about helping in immunization , accompanying clients for delivery , providing ANC and family planning services as a part of responsibility. About 99% of ASHAs knew registration of births and deaths , assisting Auxiliary Nurse Midwife (ANM in village health planning , creating awareness on basic sanitation and per sonal hygiene. CONCLUSION : Despite the training given to ASHAs , lacunae still exists in their knowledge regarding various aspects of child health morbidity. Monthly meetings can be used as a platform for the reinforcement of various aspects of child health . Periodical refresher training should be conducted for all of the recruited ASHA workers. In the future training sessions , more emphasis should be given to high risk cases requiring prompt referral.

  14. Non-catalytic site HIV-1 integrase inhibitors disrupt core maturation and induce a reverse transcription block in target cells.

    Directory of Open Access Journals (Sweden)

    Mini Balakrishnan

    Full Text Available HIV-1 integrase (IN is the target for two classes of antiretrovirals: i the integrase strand-transfer inhibitors (INSTIs and ii the non-catalytic site integrase inhibitors (NCINIs. NCINIs bind at the IN dimer interface and are thought to interfere primarily with viral DNA (vDNA integration in the target cell by blocking IN-vDNA assembly as well as the IN-LEDGF/p75 interaction. Herein we show that treatment of virus-producing cells, but not of mature virions or target cells, drives NCINI antiviral potency. NCINIs target an essential late-stage event in HIV replication that is insensitive to LEDGF levels in the producer cells. Virus particles produced in the presence of NCINIs displayed normal Gag-Pol processing and endogenous reverse transcriptase activity, but were defective at initiating vDNA synthesis following entry into the target cell. NCINI-resistant virus carrying a T174I mutation in the IN dimer interface was less sensitive to the compound-induced late-stage effects, including the reverse transcription block. Wild-type, but not T174I virus, produced in the presence of NCINIs exhibited striking defects in core morphology and an increased level of IN oligomers that was not observed upon treatment of mature cell-free particles. Collectively, these results reveal that NCINIs act through a novel mechanism that is unrelated to the previously observed inhibition of IN activity or IN-LEDGF interaction, and instead involves the disruption of an IN function during HIV-1 core maturation and assembly.

  15. Non-catalytic site HIV-1 integrase inhibitors disrupt core maturation and induce a reverse transcription block in target cells.

    Science.gov (United States)

    Balakrishnan, Mini; Yant, Stephen R; Tsai, Luong; O'Sullivan, Christopher; Bam, Rujuta A; Tsai, Angela; Niedziela-Majka, Anita; Stray, Kirsten M; Sakowicz, Roman; Cihlar, Tomas

    2013-01-01

    HIV-1 integrase (IN) is the target for two classes of antiretrovirals: i) the integrase strand-transfer inhibitors (INSTIs) and ii) the non-catalytic site integrase inhibitors (NCINIs). NCINIs bind at the IN dimer interface and are thought to interfere primarily with viral DNA (vDNA) integration in the target cell by blocking IN-vDNA assembly as well as the IN-LEDGF/p75 interaction. Herein we show that treatment of virus-producing cells, but not of mature virions or target cells, drives NCINI antiviral potency. NCINIs target an essential late-stage event in HIV replication that is insensitive to LEDGF levels in the producer cells. Virus particles produced in the presence of NCINIs displayed normal Gag-Pol processing and endogenous reverse transcriptase activity, but were defective at initiating vDNA synthesis following entry into the target cell. NCINI-resistant virus carrying a T174I mutation in the IN dimer interface was less sensitive to the compound-induced late-stage effects, including the reverse transcription block. Wild-type, but not T174I virus, produced in the presence of NCINIs exhibited striking defects in core morphology and an increased level of IN oligomers that was not observed upon treatment of mature cell-free particles. Collectively, these results reveal that NCINIs act through a novel mechanism that is unrelated to the previously observed inhibition of IN activity or IN-LEDGF interaction, and instead involves the disruption of an IN function during HIV-1 core maturation and assembly. PMID:24040198

  16. Role of fine needle aspiration cytology and cell block in diagnosis of scar endometriosis: A case report

    Directory of Open Access Journals (Sweden)

    Sashibhusan Dash

    2015-01-01

    Full Text Available Presence of endometrial glands and stroma in places other than the uterus is called endometriosis. It can be pelvic or extra-pelvic. Abdominal scar endometriosis is an extra-pelvic endometriosis that can occur after surgery involving the uterus. Post-caesarean section, scar endometriosis is a rare event. The diagnosis is frequently made only after excision of disease tissue. We present a case of post-caesarean section abdominal scar endometriosis presenting as a tumor on the abdominal wall, which was diagnosed by fine needle aspiration cytology and confirmed by cell block preparation.

  17. Block copolymer micelles target Auger electron radiotherapy to the nucleus of HER2-positive breast cancer cells.

    Science.gov (United States)

    Hoang, Bryan; Reilly, Raymond M; Allen, Christine

    2012-02-13

    Intracellular trafficking of Auger electron emitting radionuclides to perinuclear and nuclear regions of cells is critical to realizing their full therapeutic potential. In the present study, block copolymer micelles (BCMs) were labeled with the Auger electron emitter indium-111 ((111)In) and loaded with the radiosensitizer methotrexate. HER2 specific antibodies (trastuzumab fab) and nuclear localization signal (NLS; CGYGPKKKRKVGG) peptides were conjugated to the surface of the BCMs to direct uptake in HER2 expressing cells and subsequent localization in the cell nucleus. Cell uptake and intracellular distribution of the multifunctional BCMs were evaluated in a panel of breast cancer cell lines with different levels of HER2 expression. Indeed cell uptake was found to be HER2 density dependent, confirming receptor-mediated internalization of the BCMs. Importantly, conjugation of NLS peptides to the surface of BCMs was found to result in a significant increase in nuclear uptake of the radionuclide (111)In. Successful nuclear targeting was shown to improve the antipoliferative effect of the Auger electrons as measured by clonogenic assays. In addition, a significant radiation enhancement effect was observed by concurrent delivery of low-dose MTX and (111)In in all breast cancer cell lines evaluated.

  18. Reversal of rocuronium-induced neuromuscular block by the selective relaxant binding agent sugammadex: a dose-finding and safety study

    DEFF Research Database (Denmark)

    Sorgenfrei, Iben F; Norrild, Kathrine; Larsen, Per Bo;

    2006-01-01

    Sugammadex (Org 25969) forms a complex with steroidal neuromuscular blocking agents, thereby reversing neuromuscular block. This study investigated the dose-response relation, safety, and pharmacokinetics of sugammadex to reverse rocuronium-induced block....

  19. Pharmacology of the human cell voltage-dependent cation channel. Part II: inactivation and blocking

    DEFF Research Database (Denmark)

    Bennekou, Poul; Barksmann, Trine L.; Kristensen, Berit I.;

    2004-01-01

    Human red cells; Nonselective voltage-dependent cation channel; NSVDC channel; Thiol group reagents......Human red cells; Nonselective voltage-dependent cation channel; NSVDC channel; Thiol group reagents...

  20. Gadolinium block of calcium channels: influence of bicarbonate.

    Science.gov (United States)

    Boland, L M; Brown, T A; Dingledine, R

    1991-11-01

    The selectivity of block of voltage-activated barium (Ba2+) currents by lanthanide ions was studied in a rat dorsal root ganglion (DRG) cell line (F11-B9), rat and frog peripheral neurons, and rat cardiac myocytes using the whole-cell patch clamp technique. Gadolinium (Gd3+) produced a dose-dependent and complete inhibition of whole-cell Ba2+ current in all cells studied, including cells expressing identified dihydropyridine-sensitive L-type currents and omega-conotoxin-sensitive N-type currents. Like Gd3+, lutetium (Lu3+) and lanthanum (La3+) blocked all Ba2+ current with little selectivity for different components of the whole-cell current. Gd3+ block of Ba2+ currents was incomplete, however, when sodium bicarbonate (5-22.6 mM) was added to the standard HEPES-buffered external Ba2+ solution. In rat DRG neurons and F11-B9 cells, a fraction of the whole-cell Ba2+ current recorded in the presence of bicarbonate was resistant to block by saturating concentrations of Gd3+ (50-100 microM). The resistant current inactivated more rapidly than the original current giving the appearance that, under these conditions, Gd3+ block is more selective for the slowly inactivating component of the whole-cell current. Bicarbonate modification of Gd3+ block occurred both before and after omega-conotoxin block of N-type currents in rat DRG neurons, suggesting that even in the presence of bicarbonate, Gd3+ block was not selective for N-type currents. PMID:1786527

  1. Efficient high payload and Randomly selected sub-blocks image Steganography%一种高效的随机分块图像隐写算法

    Institute of Scientific and Technical Information of China (English)

    唐明伟; 胡节; 范明钰; 郑秀林

    2012-01-01

    It has been a hot area of research in information and network security in which steganography has an efficient high payload and can hide much information. ERS(an Efficient high payload and Randomly selected sub-blocks image Steganography) is proposed. The experiment results show that the method can not only reduce change of cover image, but also improve the efficient high payload. ERS is simple. Its performance is better than others in the efficiency and security of information hiding.%嵌入效率高和隐藏信息量大的信息隐藏算法,已成为信息安全领域研究的一个热点.通过对该类信息隐藏算法的分析,提出了一种高效率的随机分块信息隐藏算法ERS (an Efficient high payload and Randomly selected sub-blocks image Steganography).实验与分析结果表明:该算法不仅能够减小对载体的修改,提高嵌入效率,而且其算法实现简单、计算量小,性能优于其他算法.

  2. High Temperature Reactor (HTR) Deep Burn Core and Fuel Analysis: Design Selection for the Prismatic Block Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Francesco Venneri; Chang-Keun Jo; Jae-Man Noh; Yonghee Kim; Claudio Filippone; Jonghwa Chang; Chris Hamilton; Young-Min Kim; Ji-Su Jun; Moon-Sung Cho; Hong-Sik Lim; MIchael A. Pope; Abderrafi M. Ougouag; Vincent Descotes; Brian Boer

    2010-09-01

    The Deep Burn (DB) Project is a U.S. Department of Energy sponsored feasibility study of Transuranic Management using high burnup fuel in the high temperature helium cooled reactor (HTR). The DB Project consists of seven tasks: project management, core and fuel analysis, spent fuel management, fuel cycle integration, TRU fuel modeling, TRU fuel qualification, and HTR fuel recycle. In the Phase II of the Project, we conducted nuclear analysis of TRU destruction/utilization in the HTR prismatic block design (Task 2.1), deep burn fuel/TRISO microanalysis (Task 2.3), and synergy with fast reactors (Task 4.2). The Task 2.1 covers the core physics design, thermo-hydraulic CFD analysis, and the thermofluid and safety analysis (low pressure conduction cooling, LPCC) of the HTR prismatic block design. The Task 2.3 covers the analysis of the structural behavior of TRISO fuel containing TRU at very high burnup level, i.e. exceeding 50% of FIMA. The Task 4.2 includes the self-cleaning HTR based on recycle of HTR-generated TRU in the same HTR. Chapter IV contains the design and analysis results of the 600MWth DB-HTR core physics with the cycle length, the average discharged burnup, heavy metal and plutonium consumptions, radial and axial power distributions, temperature reactivity coefficients. Also, it contains the analysis results of the 450MWth DB-HTR core physics and the analysis of the decay heat of a TRU loaded DB-HTR core. The evaluation of the hot spot fuel temperature of the fuel block in the DB-HTR (Deep-Burn High Temperature Reactor) core under full operating power conditions are described in Chapter V. The investigated designs are the 600MWth and 460MWth DB-HTRs. In Chapter VI, the thermo-fluid and safety of the 600MWth DB-HTRs has been analyzed to investigate a thermal-fluid design performance at the steady state and a passive safety performance during an LPCC event. Chapter VII describes the analysis results of the TRISO fuel microanalysis of the 600MWth and 450

  3. A cell shrinkage-induced non-selective cation conductance with a novel pharmacology in Ehrlich-Lettre-ascites tumour cells

    DEFF Research Database (Denmark)

    Lawonn, Peter; Hoffmann, Else K; Hougaard, Charlotte;

    2003-01-01

    In whole-cell recordings on Ehrlich-Lettre-ascites tumour (ELA) cells, the shrinkage-induced activation of a cation conductance with a selectivity ratio P(Na):P(Li):P(K):P(choline):P(NMDG) of 1.00:0.97:0.88:0.03:0.01 was observed. In order of potency, this conductance was blocked by Gd(3+)=benzam......-sensitive and -insensitive channels. In addition, because of its pharmacological profile, it may possibly be related to epithelial Na+ channels (ENaCs)....

  4. Vertically aligned nanostructured TiO2 photoelectrodes for high efficiency perovskite solar cells via a block copolymer template approach

    Science.gov (United States)

    Seo, Myung-Seok; Jeong, Inyoung; Park, Joon-Suh; Lee, Jinwoo; Han, Il Ki; Lee, Wan In; Son, Hae Jung; Sohn, Byeong-Hyeok; Ko, Min Jae

    2016-06-01

    We fabricated perovskite solar cells with enhanced device efficiency based on vertically oriented TiO2 nanostructures using a nanoporous template of block copolymers (BCPs). The dimension and shape controllability of the nanopores of the BCP template allowed for the construction of one-dimensional (1-D) TiO2 nanorods and two-dimensional (2-D) TiO2 nanowalls. The TiO2 nanorod-based perovskite solar cells showed a more efficient charge separation and a lower charge recombination, leading to better performance compared to TiO2 nanowall-based solar cells. The best solar cells employing 1-D TiO2 nanorods showed an efficiency of 15.5% with VOC = 1.02 V, JSC = 20.0 mA cm-2 and fill factor = 76.1%. Thus, TiO2 nanostructures fabricated from BCP nanotemplates could be applied to the preparation of electron transport layers for improving the efficiency of perovskite solar cells.We fabricated perovskite solar cells with enhanced device efficiency based on vertically oriented TiO2 nanostructures using a nanoporous template of block copolymers (BCPs). The dimension and shape controllability of the nanopores of the BCP template allowed for the construction of one-dimensional (1-D) TiO2 nanorods and two-dimensional (2-D) TiO2 nanowalls. The TiO2 nanorod-based perovskite solar cells showed a more efficient charge separation and a lower charge recombination, leading to better performance compared to TiO2 nanowall-based solar cells. The best solar cells employing 1-D TiO2 nanorods showed an efficiency of 15.5% with VOC = 1.02 V, JSC = 20.0 mA cm-2 and fill factor = 76.1%. Thus, TiO2 nanostructures fabricated from BCP nanotemplates could be applied to the preparation of electron transport layers for improving the efficiency of perovskite solar cells. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr01010e

  5. Augmentation of CAR T-cell Trafficking and Antitumor Efficacy by Blocking Protein Kinase A Localization.

    Science.gov (United States)

    Newick, Kheng; O'Brien, Shaun; Sun, Jing; Kapoor, Veena; Maceyko, Steven; Lo, Albert; Puré, Ellen; Moon, Edmund; Albelda, Steven M

    2016-06-01

    Antitumor treatments based on the infusion of T cells expressing chimeric antigen receptors (CAR T cells) are still relatively ineffective for solid tumors, due to the presence of immunosuppressive mediators [such as prostaglandin E2 (PGE2) and adenosine] and poor T-cell trafficking. PGE2 and adenosine activate protein kinase A (PKA), which then inhibits T-cell receptor (TCR) activation. This inhibition process requires PKA to localize to the immune synapse via binding to the membrane protein ezrin. We generated CAR T cells that expressed a small peptide called the "regulatory subunit I anchoring disruptor" (RIAD) that inhibits the association of PKA with ezrin, thus blunting the negative effects of PKA on TCR activation. After exposure to PGE2 or adenosine in vitro, CAR-RIAD T cells showed increased TCR signaling, released more cytokines, and showed enhanced killing of tumor cells compared with CAR T cells. When injected into tumor-bearing mice, the antitumor efficacy of murine and human CAR-RIAD T cells was enhanced compared with that of CAR T cells, due to resistance to tumor-induced hypofunction and increased T-cell infiltration of established tumors. Subsequent in vitro assays showed that both mouse and human CAR-RIAD cells migrated more efficiently than CAR cells did in response to the chemokine CXCL10 and also had better adhesion to various matrices. Thus, the intracellular addition of the RIAD peptide to adoptively transferred CAR T cells augments their efficacy by increasing their effector function and by improving trafficking into tumor sites. This treatment strategy, therefore, shows potential clinical application for treating solid tumors. Cancer Immunol Res; 4(6); 541-51. ©2016 AACR.

  6. Band gap control using electric field of photonic gel cells fabricated with block copolymer and hydrogel.

    Science.gov (United States)

    Lee, Sung Nam; Baek, Young Bin; Shin, Dong Myung

    2014-08-01

    Optical and electrical characteristics of the devices using photonic gel film and hydrogel electrolyte were studied. Poly(styrene-b-2-vinylpyridine) (PS-b-P2VP) lamellar film with alternating hydrophobic block and hydrophilic polyelectrolyte block polymers (52 kg/mol-b-57 kg/mol) were prepared for the photonic gel. Poly(isobutylene-co-maleic acid) sodium salts were prepared for the hydrogel. This hydrogel fiber is common water swelling material and it owned ions for a device has conductivity. Photonic gel and hydrogel was spin coating onto Indium-tin-oxide (ITO) glass for make electric fields. The reflectance maximum wavelength of photonic crystal device shifted from 538 nm and reached to 557 nm, 585 nm and 604 nm during 30 min voltage applying time. The bandwidth variation was very limited. Loss of electrolyte was much less with hydrogel compared to the pure water. We can control color of hydrogel used photonic device by electric field with reasonable time range under moderate electric field by applying 2 V between two facing electrodes. PMID:25936055

  7. Integrin-mediated cell migration is blocked by inhibitors of human neuraminidase.

    Science.gov (United States)

    Jia, Feng; Howlader, Md Amran; Cairo, Christopher W

    2016-09-01

    Integrins are critical receptors in cell migration and adhesion. A number of mechanisms are known to regulate the function of integrins, including phosphorylation, conformational change, and cytoskeletal anchoring. We investigated whether native neuraminidase (Neu, or sialidase) enzymes which modify glycolipids could play a role in regulating integrin-mediated cell migration. Using a scratch assay, we found that exogenously added Neu3 and Neu4 activity altered rates of cell migration. We observed that Neu4 increased the rate of migration in two cell lines (HeLa, A549); while Neu3 only increased migration in HeLa cells. A bacterial neuraminidase was able to increase the rate of migration in HeLa, but not in A549 cells. Treatment of cells with complex gangliosides (GM1, GD1a, GD1b, and GT1b) resulted in decreased cell migration rates, while LacCer was able to increase rates of migration in both lines. Importantly, our results show that treatment of cells with inhibitors of native Neu enzymes had a dramatic effect on the rates of cell migration. The most potent compound tested targeted the human Neu4 isoenzyme, and was able to substantially reduce the rate of cell migration. We found that the lateral mobility of integrins was reduced by treatment of cells with Neu3, suggesting that Neu3 enzyme activity resulted in changes to integrin-co-receptor or integrin-cytoskeleton interactions. Finally, our results support the hypothesis that inhibitors of human Neu can be used to investigate mechanisms of cell migration and for the development of anti-adhesive therapies. PMID:27344026

  8. Integrin-mediated cell migration is blocked by inhibitors of human neuraminidase.

    Science.gov (United States)

    Jia, Feng; Howlader, Md Amran; Cairo, Christopher W

    2016-09-01

    Integrins are critical receptors in cell migration and adhesion. A number of mechanisms are known to regulate the function of integrins, including phosphorylation, conformational change, and cytoskeletal anchoring. We investigated whether native neuraminidase (Neu, or sialidase) enzymes which modify glycolipids could play a role in regulating integrin-mediated cell migration. Using a scratch assay, we found that exogenously added Neu3 and Neu4 activity altered rates of cell migration. We observed that Neu4 increased the rate of migration in two cell lines (HeLa, A549); while Neu3 only increased migration in HeLa cells. A bacterial neuraminidase was able to increase the rate of migration in HeLa, but not in A549 cells. Treatment of cells with complex gangliosides (GM1, GD1a, GD1b, and GT1b) resulted in decreased cell migration rates, while LacCer was able to increase rates of migration in both lines. Importantly, our results show that treatment of cells with inhibitors of native Neu enzymes had a dramatic effect on the rates of cell migration. The most potent compound tested targeted the human Neu4 isoenzyme, and was able to substantially reduce the rate of cell migration. We found that the lateral mobility of integrins was reduced by treatment of cells with Neu3, suggesting that Neu3 enzyme activity resulted in changes to integrin-co-receptor or integrin-cytoskeleton interactions. Finally, our results support the hypothesis that inhibitors of human Neu can be used to investigate mechanisms of cell migration and for the development of anti-adhesive therapies.

  9. Heart Block

    Science.gov (United States)

    ... the signal causes the heart to contract and pump blood. Heart block occurs if the electrical signal is ... degree heart block limits the heart's ability to pump blood to the rest of the body. This type ...

  10. Regulated selection of germinal-center cells into the memory B cell compartment.

    Science.gov (United States)

    Shinnakasu, Ryo; Inoue, Takeshi; Kometani, Kohei; Moriyama, Saya; Adachi, Yu; Nakayama, Manabu; Takahashi, Yoshimasa; Fukuyama, Hidehiro; Okada, Takaharu; Kurosaki, Tomohiro

    2016-07-01

    Despite the importance of memory B cells in protection from reinfection, how such memory cells are selected and generated during germinal-center (GC) reactions remains unclear. We found here that light-zone (LZ) GC B cells with B cell antigen receptors (BCRs) of lower affinity were prone to enter the memory B cell pool. Mechanistically, cells in this memory-prone fraction had higher expression of the transcriptional repressor Bach2 than that of their counterparts with BCRs of higher affinity. Haploinsufficiency of Bach2 resulted in reduced generation of memory B cells, independently of suppression of the gene encoding the transcription factor Blimp-1. Bach2 expression in GC cells was inversely correlated with the strength of help provided by T cells. Thus, we propose an instructive model in which weak help from T cells maintains relatively high expression of Bach2, which predisposes GC cells to enter the memory pool.

  11. Lumican Inhibits SNAIL-Induced Melanoma Cell Migration Specifically by Blocking MMP-14 Activity

    Science.gov (United States)

    Stasiak, Marta; Boncela, Joanna; Perreau, Corinne; Karamanou, Konstantina; Chatron-Colliet, Aurore; Proult, Isabelle; Przygodzka, Patrycja; Chakravarti, Shukti; Maquart, François-Xavier; Kowalska, M. Anna; Wegrowski, Yanusz; Brézillon, Stéphane

    2016-01-01

    Lumican, a small leucine rich proteoglycan, inhibits MMP-14 activity and melanoma cell migration in vitro and in vivo. Snail triggers epithelial-mesenchymal transitions endowing epithelial cells with migratory and invasive properties during tumor progression. The aim of this work was to investigate lumican effects on MMP-14 activity and migration of Snail overexpressing B16F1 (Snail-B16F1) melanoma cells and HT-29 colon adenocarcinoma cells. Lumican inhibits the Snail induced MMP-14 activity in B16F1 but not in HT-29 cells. In Snail-B16F1 cells, lumican inhibits migration, growth, and melanoma primary tumor development. A lumican-based strategy targeting Snail-induced MMP-14 activity might be useful for melanoma treatment. PMID:26930497

  12. Conformationally blocked quinoxaline cavitand as solid-phase microextraction coating for the selective detection of BTEX in air.

    Science.gov (United States)

    Riboni, N; Trzcinski, J W; Bianchi, F; Massera, C; Pinalli, R; Sidisky, L; Dalcanale, E; Careri, M

    2016-01-28

    A tetraquinoxaline cavitand functionalized with methylenoxy bridges at the upper rim is proposed as selective solid-phase microextraction (SPME) coating for the determination of BTEX at trace levels in air. The SPME fibers were characterized in terms of film thickness, morphology, thermal stability and extraction capabilities. An average coating thickness of 35 (±4) μm, a thermal stability up to 350 °C and a good fiber-to-fiber and batch-to-batch repeatability with RSD lower than 15% were obtained. Excellent enrichment factors ranging from 360-700 × 10(3) were obtained for the investigated compounds. Finally, method validation proved the capabilities of the developed coating for the selective sampling of BTEX, achieving LOD values in the 0.4-1.2 ng m(-3) range.

  13. Dexamethasone blocks the migration of the human neuroblastoma cell line SK-N-SH

    Directory of Open Access Journals (Sweden)

    Casulari L.A.

    2006-01-01

    Full Text Available Glucocorticoids (Gc influence the differentiation of neural crest-derived cells such as those composing sympathoadrenal tumors like pheochromocytomas, as well as neuroblastomas and gangliomas. In order to obtain further information on the effects of Gc on cells evolving from the neural crest, we have used the human neuroblastoma cell line SK-N-SH to analyze: 1 the presence and the binding characteristics of Gc receptors in these cells, 2 the effect of dexamethasone (Dex on the migration of SK-N-SH cells, and 3 the effect of Dex on the organization of the cytoskeleton of SK-N-SH cells. We show that: 1 receptors that bind [³H]-Dex with high affinity and high capacity (Kd of 9.6 nM, Bmax of 47 fmol/mg cytosolic protein, corresponding to 28,303 sites/cell are present in cytosolic preparations of SK-N-SH cells, and 2 treatment with Dex (in the range of 10 nM to 1 µM has an inhibitory effect (from 100% to 74 and 43%, respectively on the chemotaxis of SK-N-SH cells elicited by fetal bovine serum. This inhibition is completely reversed by the Gc receptor antagonist RU486 (1 µM, and 3 as demonstrated by fluorescent phalloidin-actin detection, the effect of Dex (100 nM on SK-N-SH cell migration is accompanied by modifications of the cytoskeleton organization that appear with stress fibers. These modifications did not take place in the presence of 1 µM RU486. The present data demonstrate for the first time that Dex affects the migration of neuroblastoma cells as well as their cytoskeleton organization by interacting with specific receptors. These findings provide new insights on the mechanism(s of action of Gc on cells originating in the neural crest.

  14. Use of Surface Enhanced Blocking (SEB) Electrodes for Microbial Cell Lysis in Flow-Through Devices

    OpenAIRE

    Talebpour, Abdossamad; Maaskant, Robert; Khine, Aye Aye; Alavie, Tino

    2014-01-01

    By simultaneously subjecting microbial cells to high amplitude pulsed electric fields and flash heating of the cell suspension fluid, effective release of intracellular contents was achieved. The synergistic effect of the applied electric field and elevated temperature on cell lysis in a flow-through device was demonstrated for Gram-negative and Gram-positive bacteria, and Mycobacterium species. The resulting lysate is suitable for downstream nucleic acid amplification and detection without r...

  15. Selective Antitumor Activity of Ibrutinib in EGFR-Mutant Non–Small Cell Lung Cancer Cells

    OpenAIRE

    Gao, Wen; Wang, Michael; Wang, Li; Lu, Haibo; Wu, Shuhong; Dai, Bingbing; Ou, Zhishuo; Zhang, Liang; Heymach, John V.; Gold, Kathryn A.; Minna, John ,; Roth, Jack A.; Hofstetter, Wayne L.; Swisher, Stephen G.; Fang, Bingliang

    2014-01-01

    Ibrutinib, which irreversibly inhibits Bruton tyrosine kinase, was evaluated for antitumor activity in a panel of non–small cell lung cancer (NSCLC) cell lines and found to selectively inhibit growth of NSCLC cells carrying mutations in the epidermal growth factor receptor (EGFR) gene, including T790M mutant and erlotinib-resistant H1975 cells. Ibrutinib induced dose-dependent inhibition of phosphor-EGFR at both Y1068 and Y1173 sites, suggesting ibrutinib functions as an EGFR inhibitor. Survi...

  16. Chfr acts with the p38 stress kinases to block entry to mitosis in mammalian cells

    OpenAIRE

    Matsusaka, Takahiro; Pines, Jonathon

    2004-01-01

    Entry into mitosis in vertebrate cells is guarded by a checkpoint that can be activated by a variety of insults, including chromosomal damage and disrupting microtubules (Rieder, C.L., and R.W. Cole. 1998. J. Cell Biol. 142:1013–1022; Rieder, C.L., and R.W. Cole. 2000. Curr. Biol. 10:1067–1070). This checkpoint acts at the end of interphase to delay cells from entering mitosis, causing cells in prophase to decondense their chromosomes and return to G2 phase. Here, we show that in response to ...

  17. Cell-block procedure in endoscopic ultrasound-guided-fine-needle-aspiration of gastrointestinal solid neoplastic lesions

    Institute of Scientific and Technical Information of China (English)

    Antonio; Ieni; Valeria; Barresi; Paolo; Todaro; Rosario; Alberto; Caruso; Giovanni; Tuccari

    2015-01-01

    In the present review we have analyzed the clinical applications of endoscopic ultrasound-guided-fineneedle-aspiration(EUS-FNA) and the methodological aspects obtained by cell-block procedure(CBP) in the diagnostic approach to the gastrointestinal neoplastic pathology. CBP showed numerous advantages in comparison to the cytologic routine smears; in particular, better preservation of cell architecture, achievement of routine haematoxylin-eosin staining equivalent to histological slides and possibility to perform immunohistochemistry or molecular analyses represented the most evident reasons to choose this method. Moreover, by this approach, the differential diagnosis of solid gastrointestinal neoplasias may be more easily achieved and the background of contaminant nonneoplastic gastrointestinal avoided. Finally, biological samples collected by EUS-FNA CBP-assisted should be investigated in order to identify and quantify further potential molecular markers.

  18. Insulin-like growth factors require phosphatidylinositol 3-kinase to signal myogenesis: dominant negative p85 expression blocks differentiation of L6E9 muscle cells.

    Science.gov (United States)

    Kaliman, P; Canicio, J; Shepherd, P R; Beeton, C A; Testar, X; Palacín, M; Zorzano, A

    1998-01-01

    Phosphatidylinositol 3 (PI 3)-kinases are potently inhibited by two structurally unrelated membrane-permeant reagents: wortmannin and LY294002. By using these two inhibitors we first suggested the involvement of a PI 3-kinase activity in muscle cell differentiation. However, several reports have described that these compounds are not as selective for PI 3-kinase activity as assumed. Here we show that LY294002 blocks the myogenic pathway elicited by insulin-like growth factors (IGFs), and we confirm the specific involvement of PI 3-kinase in IGF-induced myogenesis by overexpressing in L6E9 myoblasts a dominant negative p85 PI 3-kinase-regulatory subunit (L6E9-delta p85). IGF-I, des(1-3)IGF-I, or IGF-II induced L6E9 skeletal muscle cell differentiation as measured by myotube formation, myogenin gene expression, and GLUT4 glucose carrier induction. The addition of LY294002 to the differentiation medium totally inhibited these IGF-induced myogenic events without altering the expression of a non-muscle-specific protein, beta1-integrin. Independent clones of L6E9 myoblasts expressing a dominant negative mutant of the p85-regulatory subunit (delta p85) showed markedly impaired glucose transport activity and formation of p85/p110 complexes in response to insulin, consistent with the inhibition of PI 3-kinase activity. IGF-induced myogenic parameters in L6E9-delta p85 cells, ie. cell fusion and myogenin gene and GLUT4 expression, were severely impaired compared with parental cells or L6E9 cells expressing wild-type p85. In all, data presented here indicate that PI 3-kinase is essential for IGF-induced muscle differentiation and that the specific PI 3-kinase subclass involved in myogenesis is the heterodimeric p85-p110 enzyme. PMID:9440811

  19. Building Cell Selectivity into CPP-Mediated Strategies

    Directory of Open Access Journals (Sweden)

    Irene Martín

    2010-05-01

    Full Text Available There is a pressing need for more effective and selective therapies for cancer and other diseases. Consequently, much effort is being devoted to the development of alternative experimental approaches based on selective systems, which are designed to be specifically directed against target cells. In addition, a large number of highly potent therapeutic molecules are being discovered. However, they do not reach clinical trials because of their low delivery, poor specificity or their incapacity to bypass the plasma membrane. Cell-penetrating peptides (CPPs are an open door for cell-impermeable compounds to reach intracellular targets. Putting all these together, research is sailing in the direction of the design of systems with the capacity to transport new drugs into a target cell. Some CPPs show cell type specificity while others require modifications or form part of more sophisticated drug delivery systems. In this review article we summarize several strategies for directed drug delivery involving CPPs that have been reported in the literature.

  20. Population Blocks.

    Science.gov (United States)

    Smith, Martin H.

    1992-01-01

    Describes an educational game called "Population Blocks" that is designed to illustrate the concept of exponential growth of the human population and some potential effects of overpopulation. The game material consists of wooden blocks; 18 blocks are painted green (representing land), 7 are painted blue (representing water); and the remaining…

  1. Selective nickel-catalyzed conversion of model and lignin-derived phenolic compounds to cyclohexanone-based polymer building blocks.

    Science.gov (United States)

    Schutyser, Wouter; Van den Bosch, Sander; Dijkmans, Jan; Turner, Stuart; Meledina, Maria; Van Tendeloo, Gustaaf; Debecker, Damien P; Sels, Bert F

    2015-05-22

    Valorization of lignin is essential for the economics of future lignocellulosic biorefineries. Lignin is converted into novel polymer building blocks through four steps: catalytic hydroprocessing of softwood to form 4-alkylguaiacols, their conversion into 4-alkylcyclohexanols, followed by dehydrogenation to form cyclohexanones, and Baeyer-Villiger oxidation to give caprolactones. The formation of alkylated cyclohexanols is one of the most difficult steps in the series. A liquid-phase process in the presence of nickel on CeO2 or ZrO2 catalysts is demonstrated herein to give the highest cyclohexanol yields. The catalytic reaction with 4-alkylguaiacols follows two parallel pathways with comparable rates: 1) ring hydrogenation with the formation of the corresponding alkylated 2-methoxycyclohexanol, and 2) demethoxylation to form 4-alkylphenol. Although subsequent phenol to cyclohexanol conversion is fast, the rate is limited for the removal of the methoxy group from 2-methoxycyclohexanol. Overall, this last reaction is the rate-limiting step and requires a sufficient temperature (>250 °C) to overcome the energy barrier. Substrate reactivity (with respect to the type of alkyl chain) and details of the catalyst properties (nickel loading and nickel particle size) on the reaction rates are reported in detail for the Ni/CeO2 catalyst. The best Ni/CeO2 catalyst reaches 4-alkylcyclohexanol yields over 80 %, is even able to convert real softwood-derived guaiacol mixtures and can be reused in subsequent experiments. A proof of principle of the projected cascade conversion of lignocellulose feedstock entirely into caprolactone is demonstrated by using Cu/ZrO2 for the dehydrogenation step to produce the resultant cyclohexanones (≈80 %) and tin-containing beta zeolite to form 4-alkyl-ε-caprolactones in high yields, according to a Baeyer-Villiger-type oxidation with H2 O2 .

  2. Imidazolium-based Block Copolymers as Solid-State Separators for Alkaline Fuel Cells and Lithium Ion Batteries

    Science.gov (United States)

    Nykaza, Jacob Richard

    In this study, polymerized ionic liquid (PIL) diblock copolymers were explored as solid-state polymer separators as an anion exchange membrane (AEM) for alkaline fuel cells AFCs and as a solid polymer electrolyte (SPE) for lithium-ion batteries. Polymerized ionic liquid (PIL) block copolymers are a distinct set of block copolymers that combine the properties of both ionic liquids (e.g., high conductivity, high electrochemical stability) and block copolymers (e.g., self-assembly into various nanostructures), which provides the opportunity to design highly conductive robust solid-state electrolytes that can be tuned for various applications including AFCs and lithium-ion batteries via simple anion exchange. A series of bromide conducting PIL diblock copolymers with an undecyl alkyl side chain between the polymer backbone and the imidazolium moiety were first synthesized at various compositions comprising of a PIL component and a non-ionic component. Synthesis was achieved by post-functionalization from its non-ionic precursor PIL diblock copolymer, which was synthesized via the reverse addition fragmentation chain transfer (RAFT) technique. This PIL diblock copolymer with long alkyl side chains resulted in flexible, transparent films with high mechanical strength and high bromide ion conductivity. The conductivity of the PIL diblock copolymer was three times higher than its analogous PIL homopolymer and an order of magnitude higher than a similar PIL diblock copolymer with shorter alkyl side chain length, which was due to the microphase separated morphology, more specifically, water/ion clusters within the PIL microdomains in the hydrated state. Due to the high conductivity and mechanical robustness of this novel PIL block copolymer, its application as both the ionomer and AEM in an AFC was investigated via anion exchange to hydroxide (OH-), where a maximum power density of 29.3 mW cm-1 (60 °C with H2/O2 at 25 psig (172 kPa) backpressure) was achieved. Rotating disk

  3. HIF-1α inhibition blocks the cross talk between multiple myeloma plasma cells and tumor microenvironment

    International Nuclear Information System (INIS)

    Multiple myeloma (MM) is a malignant disorder of post-germinal center B cells, characterized by the clonal proliferation of malignant plasma cells (PCs) within the bone marrow (BM). The reciprocal and complex interactions that take place between the different compartments of BM and the MM cells result in tumor growth, angiogenesis, bone disease, and drug resistance. Given the importance of the BM microenvironment in MM pathogenesis, we investigated the possible involvement of Hypoxia-Inducible transcription Factor-1 alpha (HIF-1α) in the PCs-bone marrow stromal cells interplay. To test this hypothesis, we used EZN-2968, a 3rd generation antisense oligonucleotide against HIF-1α, to inhibit HIF-1α functions. Herein, we provide evidence that the interaction between MM cells and BM stromal cells is drastically reduced upon HIF-1α down-modulation. Notably, we showed that upon exposure to HIF-1α inhibitor, neither the incubation with IL-6 nor the co-culture with BM stromal cells were able to revert the anti-proliferative effect induced by EZN-2968. Moreover, we observed a down-modulation of cytokine-induced signaling cascades and a reduction of MM cells adhesion capability to the extracellular matrix proteins in EZN-2968-treated samples. Taken together, these results strongly support the concept that HIF-1α plays a critical role in the interactions between bone BM cells and PCs in Multiple Myeloma. - Highlights: • HIF-1α inhibition induces a mild apoptotic cell death. • Down-modulation of cytokine-induced signaling cascades upon HIF-1α inhibition. • Reduced interaction between MM cells and BMSCs upon HIF-1α down-modulation. • Reduced PCs adhesion to the extracellular matrix protein induced by EZN-2968. • HIF-1α inhibition may be an attractive therapeutic strategy for Multiple Myeloma

  4. HIF-1α inhibition blocks the cross talk between multiple myeloma plasma cells and tumor microenvironment

    Energy Technology Data Exchange (ETDEWEB)

    Borsi, Enrica, E-mail: enrica.borsi2@unibo.it [Department of Experimental Diagnostic and Specialty Medicine (DIMES), “L. and A. Seràgnoli”, Bologna University School of Medicine, S. Orsola' s University Hospital (Italy); Perrone, Giulia [Fondazione IRCCS Istituto Nazionale dei Tumori, Hematology Department, Via Venezian 1, 20133 Milano (Italy); Terragna, Carolina; Martello, Marina; Zamagni, Elena; Tacchetti, Paola; Pantani, Lucia; Brioli, Annamaria; Dico, Angela Flores; Zannetti, Beatrice Anna; Rocchi, Serena; Cavo, Michele [Department of Experimental Diagnostic and Specialty Medicine (DIMES), “L. and A. Seràgnoli”, Bologna University School of Medicine, S. Orsola' s University Hospital (Italy)

    2014-11-01

    Multiple myeloma (MM) is a malignant disorder of post-germinal center B cells, characterized by the clonal proliferation of malignant plasma cells (PCs) within the bone marrow (BM). The reciprocal and complex interactions that take place between the different compartments of BM and the MM cells result in tumor growth, angiogenesis, bone disease, and drug resistance. Given the importance of the BM microenvironment in MM pathogenesis, we investigated the possible involvement of Hypoxia-Inducible transcription Factor-1 alpha (HIF-1α) in the PCs-bone marrow stromal cells interplay. To test this hypothesis, we used EZN-2968, a 3rd generation antisense oligonucleotide against HIF-1α, to inhibit HIF-1α functions. Herein, we provide evidence that the interaction between MM cells and BM stromal cells is drastically reduced upon HIF-1α down-modulation. Notably, we showed that upon exposure to HIF-1α inhibitor, neither the incubation with IL-6 nor the co-culture with BM stromal cells were able to revert the anti-proliferative effect induced by EZN-2968. Moreover, we observed a down-modulation of cytokine-induced signaling cascades and a reduction of MM cells adhesion capability to the extracellular matrix proteins in EZN-2968-treated samples. Taken together, these results strongly support the concept that HIF-1α plays a critical role in the interactions between bone BM cells and PCs in Multiple Myeloma. - Highlights: • HIF-1α inhibition induces a mild apoptotic cell death. • Down-modulation of cytokine-induced signaling cascades upon HIF-1α inhibition. • Reduced interaction between MM cells and BMSCs upon HIF-1α down-modulation. • Reduced PCs adhesion to the extracellular matrix protein induced by EZN-2968. • HIF-1α inhibition may be an attractive therapeutic strategy for Multiple Myeloma.

  5. Latent Epstein-Barr virus can inhibit apoptosis in B cells by blocking the induction of NOXA expression.

    Directory of Open Access Journals (Sweden)

    Jade Yee

    Full Text Available Latent Epstein-Barr virus (EBV has been shown to protect Burkitt's lymphoma-derived B cells from apoptosis induced by agents that cause damage to DNA, in the context of mutant p53. This protection requires expression of the latency-associated nuclear proteins EBNA3A and EBNA3C and correlates with their ability to cooperate in the repression of the gene encoding the pro-apoptotic, BH3-only protein BIM. Here we confirm that latent EBV in B cells also inhibits apoptosis induced by two other agents--ionomycin and staurosporine--and show that these act by a distinct pathway that involves a p53-independent increase in expression of another pro-apoptotic, BH3-only protein, NOXA. Analyses employing a variety of B cells infected with naturally occurring EBV or B95.8 EBV-BAC recombinant mutants indicated that the block to NOXA induction does not depend on the well-characterized viral latency-associated genes (EBNAs 1, 2, 3A, 3B, 3C, the LMPs or the EBERs or expression of BIM. Regulation of NOXA was shown to be at least partly at the level of mRNA and the requirement for NOXA to induce cell death in this context was demonstrated by NOXA-specific shRNA-mediated depletion experiments. Although recombinant EBV with a deletion removing the BHRF1 locus--that encodes the BCL2-homologue BHRF1 and three microRNAs--partially abrogates protection against ionomycin and staurosporine, the deletion has no effect on the EBV-mediated block to NOXA accumulation.

  6. Pancreatic α-Cell Dysfunction in Type 2 Diabetes: Old Kids on the Block

    Directory of Open Access Journals (Sweden)

    Jun Sung Moon

    2015-02-01

    Full Text Available Type 2 diabetes (T2D has been known as 'bi-hormonal disorder' since decades ago, the role of glucagon from α-cell has languished whereas β-cell taking center stage. Recently, numerous findings indicate that the defects of glucagon secretion get involve with development and exacerbation of hyperglycemia in T2D. Aberrant α-cell responses exhibit both fasting and postprandial states: hyperglucagonemia contributes to fasting hyperglycemia caused by inappropriate hepatic glucose production, and to postprandial hyperglycemia owing to blunted α-cell suppression. During hypoglycemia, insufficient counter-regulation response is also observed in advanced T2D. Though many debates still remained for exact mechanisms behind the dysregulation of α-cell in T2D, it is clear that the blockade of glucagon receptor or suppression of glucagon secretion from α-cell would be novel therapeutic targets for control of hyperglycemia. Whereas there have not been remarkable advances in developing new class of drugs, currently available glucagon-like peptide-1 and dipeptidyl peptidase-IV inhibitors could be options for treatment of hyperglucagonemia. In this review, we focus on α-cell dysfunction and therapeutic potentials of targeting α-cell in T2D.

  7. Ion-selective microelectrode arrays for cell culture monitoring

    OpenAIRE

    Generelli, Silvia; De Rooij, Nicolas-F.

    2008-01-01

    The design, microfabrication and characterization of a platform comprising an array of ion-selective microelectrodes (µISE) aimed at in vitro cellular physiology and toxicology is described. This study focusses on K+ and Ca2+ monitoring in cell culture environments. A potential promising application of such a platform is based on recent findings in molecular biology, revealing connections between certain diseases, as for example some types of cancer or parkinsonism, and a malfunction in cellu...

  8. The tight junction protein ZO-2 blocks cell cycle progression and inhibits cyclin D1 expression.

    Science.gov (United States)

    Gonzalez-Mariscal, Lorenza; Tapia, Rocio; Huerta, Miriam; Lopez-Bayghen, Esther

    2009-05-01

    ZO-2 is an adaptor protein of the tight junction that belongs to the MAGUK protein family. ZO-2 is a dual localization protein that in sparse cultures is present at the cell borders and the nuclei, whereas in confluent cultures it is concentrated at the cell boundaries. Here we have studied whether ZO-2 is able to regulate the expression of cyclin D1 (CD1) and cell proliferation. We have demonstrated that ZO-2 negatively regulates CD1 transcription by interacting with c-Myc at an E box present in CD1 promoter. We have further found that ZO-2 transfection into epithelial MDCK cells triggers a diminished expression of CD1 protein and decreases the rate of cell proliferation in a wound-healing assay.

  9. Blocking TLR7- and TLR9-mediated IFN-α production by plasmacytoid dendritic cells does not diminish immune activation in early SIV infection.

    Directory of Open Access Journals (Sweden)

    Muhamuda Kader

    Full Text Available Persistent production of type I interferon (IFN by activated plasmacytoid dendritic cells (pDC is a leading model to explain chronic immune activation in human immunodeficiency virus (HIV infection but direct evidence for this is lacking. We used a dual antagonist of Toll-like receptor (TLR 7 and TLR9 to selectively inhibit responses of pDC but not other mononuclear phagocytes to viral RNA prior to and for 8 weeks following pathogenic simian immunodeficiency virus (SIV infection of rhesus macaques. We show that pDC are major but not exclusive producers of IFN-α that rapidly become unresponsive to virus stimulation following SIV infection, whereas myeloid DC gain the capacity to produce IFN-α, albeit at low levels. pDC mediate a marked but transient IFN-α response in lymph nodes during the acute phase that is blocked by administration of TLR7 and TLR9 antagonist without impacting pDC recruitment. TLR7 and TLR9 blockade did not impact virus load or the acute IFN-α response in plasma and had minimal effect on expression of IFN-stimulated genes in both blood and lymph node. TLR7 and TLR9 blockade did not prevent activation of memory CD4+ and CD8+ T cells in blood or lymph node but led to significant increases in proliferation of both subsets in blood following SIV infection. Our findings reveal that virus-mediated activation of pDC through TLR7 and TLR9 contributes to substantial but transient IFN-α production following pathogenic SIV infection. However, the data indicate that pDC activation and IFN-α production are unlikely to be major factors in driving immune activation in early infection. Based on these findings therapeutic strategies aimed at blocking pDC function and IFN-α production may not reduce HIV-associated immunopathology.

  10. Micronuclei induced by reverse transcriptase inhibitors in mononucleated and binucleated cells as assessed by the cytokinesis-block micronucleus assay

    Science.gov (United States)

    2010-01-01

    This study evaluated the clastogenic and/or aneugenic potential of three nucleoside reverse transcriptase inhibitors (zidovudine - AZT, lamivudine - 3TC and stavudine - d4T) using the cytokinesis-block micronucleus (CBMN) assay in human lymphocyte cultures. All three inhibitors produced a positive response when tested in binucleated cells. The genotoxicity of AZT and 3TC was restricted to binucleated cells since there was no significant increase in the frequency of micronuclei in mononucleated cells. This finding indicated that AZT and 3TC caused chromosomal breakage and that their genotoxicity was related to a clastogenic action. In addition to the positive response observed with d4T in binucleated cells, this drug also increased the frequency of micronuclei in mononucleated cells, indicating clastogenic and aneugenic actions. Since the structural differences between AZT and 3TC and AZT and d4T involve the 3' position in the 2'-deoxyribonucleoside and in an unsaturated 2',3',dideoxyribose, respectively, we suggest that an unsaturated 2', 3', dideoxyribose is responsible for the clastogenic and aneugenic actions of d4T. PMID:21637587

  11. PAN-811 Blocks Chemotherapy Drug-Induced In Vitro Neurotoxicity, While Not Affecting Suppression of Cancer Cell Growth

    Directory of Open Access Journals (Sweden)

    Zhi-Gang Jiang

    2016-01-01

    Full Text Available Chemotherapy often results in cognitive impairment, and no neuroprotective drug is now available. This study aimed to understand underlying neurotoxicological mechanisms of anticancer drugs and to evaluate neuroprotective effects of PAN-811. Primary neurons in different concentrations of antioxidants (AOs were insulted for 3 days with methotrexate (MTX, 5-fluorouracil (5-FU, or cisplatin (CDDP in the absence or presence of PAN-811·Cl·H2O. The effect of PAN-811 on the anticancer activity of tested drugs was also examined using mouse and human cancer cells (BNLT3 and H460 to assess any negative interference. Cell membrane integrity, survival, and death and intramitochondrial reactive oxygen species (ROS were measured. All tested anticancer drugs elicited neurotoxicity only under low levels of AO and elicited a ROS increase. These results suggested that ROS mediates neurotoxicity of tested anticancer drugs. PAN-811 dose-dependently suppressed increased ROS and blocked the neurotoxicity when neurons were insulted with a tested anticancer drug. PAN-811 did not interfere with anticancer activity of anticancer drugs against BNLT3 cells. PAN-811 did not inhibit MTX-induced death of H460 cells but, interestingly, demonstrated a synergistic effect with 5-FU or CDDP in reducing cancer cell viability. Thus, PAN-811 can be a potent drug candidate for chemotherapy-induced cognitive impairment.

  12. Emodin Inhibits Breast Cancer Growth by Blocking the Tumor-Promoting Feedforward Loop between Cancer Cells and Macrophages.

    Science.gov (United States)

    Iwanowycz, Stephen; Wang, Junfeng; Hodge, Johnie; Wang, Yuzhen; Yu, Fang; Fan, Daping

    2016-08-01

    Macrophage infiltration correlates with severity in many types of cancer. Tumor cells recruit macrophages and educate them to adopt an M2-like phenotype through the secretion of chemokines and growth factors, such as MCP1 and CSF1. Macrophages in turn promote tumor growth through supporting angiogenesis, suppressing antitumor immunity, modulating extracellular matrix remodeling, and promoting tumor cell migration. Thus, tumor cells and macrophages interact to create a feedforward loop supporting tumor growth and metastasis. In this study, we tested the ability of emodin, a Chinese herb-derived compound, to inhibit breast cancer growth in mice and examined the underlying mechanisms. Emodin was used to treat mice bearing EO771 or 4T1 breast tumors. It was shown that emodin attenuated tumor growth by inhibiting macrophage infiltration and M2-like polarization, accompanied by increased T-cell activation and reduced angiogenesis in tumors. The tumor inhibitory effects of emodin were lost in tumor-bearing mice with macrophage depletion. Emodin inhibited IRF4, STAT6, and C/EBPβ signaling and increased inhibitory histone H3 lysine 27 tri-methylation (H3K27m3) on the promoters of M2-related genes in tumor-associated macrophages. In addition, emodin inhibited tumor cell secretion of MCP1 and CSF1, as well as expression of surface anchoring molecule Thy-1, thus suppressing macrophage migration toward and adhesion to tumor cells. These results suggest that emodin acts on both breast cancer cells and macrophages and effectively blocks the tumor-promoting feedforward loop between the two cell types, thereby inhibiting breast cancer growth and metastasis. Mol Cancer Ther; 15(8); 1931-42. ©2016 AACR. PMID:27196773

  13. Macrolide analog F806 suppresses esophageal squamous cell carcinoma (ESCC) by blocking β1 integrin activation.

    Science.gov (United States)

    Li, Li-Yan; Jiang, Hong; Xie, Yang-Min; Liao, Lian-Di; Cao, Hui-Hui; Xu, Xiu-E; Chen, Bo; Zeng, Fa-Min; Zhang, Ying-Li; Du, Ze-Peng; Chen, Hong; Huang, Wei; Jia, Wei; Zheng, Wei; Xie, Jian-Jun; Li, En-Min; Xu, Li-Yan

    2015-06-30

    The paucity of new drugs for the treatment of esophageal squamous cell carcinoma (ESCC) limits the treatment options. This study characterized the therapeutic efficacy and action mechanism of a novel natural macrolide compound F806 in human ESCC xenograft models and cell lines. F806 inhibited growth of ESCC, most importantly, it displayed fewer undesirable side effects on normal tissues in two human ESCC xenograft models. F806 inhibited proliferation of six ESCC cells lines, with the half maximal inhibitory concentration (IC50) ranging from 9.31 to 16.43 μM. Furthermore, F806 induced apoptosis of ESCC cells, contributing to its growth-inhibitory effect. Also, F806 inhibited cell adhesion resulting in anoikis. Mechanistic studies revealed that F806 inhibited the activation of β1 integrin in part by binding to a novel site Arg610 of β1 integrin, suppressed focal adhesion formation, decreased cell adhesion to extracellular matrix and eventually triggered apoptosis. We concluded that F806 would potentially be a well-tolerated anticancer drug by targeting β1 integrin, resulting in anoikis in ESCC cells.

  14. Amygdalin Blocks Bladder Cancer Cell Growth In Vitro by Diminishing Cyclin A and cdk2

    OpenAIRE

    Jasmina Makarević; Jochen Rutz; Eva Juengel; Silke Kaulfuss; Michael Reiter; Igor Tsaur; Georg Bartsch; Axel Haferkamp; Blaheta, Roman A.

    2014-01-01

    Amygdalin, a natural compound, has been used by many cancer patients as an alternative approach to treat their illness. However, whether or not this substance truly exerts an anti-tumor effect has never been settled. An in vitro study was initiated to investigate the influence of amygdalin (1.25-10 mg/ml) on the growth of a panel of bladder cancer cell lines (UMUC-3, RT112 and TCCSUP). Tumor growth, proliferation, clonal growth and cell cycle progression were investigated. The cell cycle regu...

  15. Analysis of TANOS Memory Cells With Sealing Oxide Containing Blocking Dielectric

    OpenAIRE

    Beug, M. Florian; Melde, Thomas; Czernohorsky, Malte; Hoffmann, Raik; Paul, Jan; Knöfler, Roman; Tilke, Armin T.

    2010-01-01

    In this paper, we investigate the specific impact of an additional silicon oxide layer (sealing oxide) on top of the charge-trap nitride on the electrical performance of small dimension and large TANOS charge-trapping (CT) memory cells. We observe a significant improvement in charge retention on both our target 48-nm NAND TANOS cells and on large 5 µm long and wide memory cells. However, erase performance is partially degraded by this additional silicon dioxide top-dielectric layer. The prese...

  16. Cytokine-dependent and–independent gene expression changes and cell cycle block revealed in Trypanosoma cruzi-infected host cells by comparative mRNA profiling

    Directory of Open Access Journals (Sweden)

    Burleigh Barbara A

    2009-05-01

    Full Text Available Abstract Background The requirements for growth and survival of the intracellular pathogen Trypanosoma cruzi within mammalian host cells are poorly understood. Transcriptional profiling of the host cell response to infection serves as a rapid read-out for perturbation of host physiology that, in part, reflects adaptation to the infective process. Using Affymetrix oligonucleotide array analysis we identified common and disparate host cell responses triggered by T. cruzi infection of phenotypically diverse human cell types. Results We report significant changes in transcript abundance in T. cruzi-infected fibroblasts, endothelial cells and smooth muscle cells (2852, 2155 and 531 genes respectively; fold-change ≥ 2, p-value T. cruzi-infected fibroblasts and endothelial cells transwell plates were used to distinguish cytokine-dependent and -independent gene expression profiles. This approach revealed the induction of metabolic and signaling pathways involved in cell proliferation, amino acid catabolism and response to wounding as common themes in T. cruzi-infected cells. In addition, the downregulation of genes involved in mitotic cell cycle and cell division predicted that T. cruzi infection may impede host cell cycle progression. The observation of impaired cytokinesis in T. cruzi-infected cells, following nuclear replication, confirmed this prediction. Conclusion Metabolic pathways and cellular processes were identified as significantly altered at the transcriptional level in response to T. cruzi infection in a cytokine-independent manner. Several of these alterations are supported by previous studies of T. cruzi metabolic requirements or effects on the host. However, our methods also revealed a T. cruzi-dependent block in the host cell cycle, at the level of cytokinesis, previously unrecognized for this pathogen-host cell interaction.

  17. Selective-emitter crystalline silicon solar cells using phosphorus paste

    International Nuclear Information System (INIS)

    Selective-emitter structures have been studied to improve the conversion efficiency of crystalline silicon solar cells. However, such structures require additional complicated processes and incur extra cost. In this work, we used phosphorus paste (P-paste) to form a heavily-doped region beneath the grid and POCl3 to create a shallow emitter area. This method should be convenient to use in the solar-cell industry because it requires only additional P paste printing, compared to the case of homogeneous solar cells. Diffusion parameters including the temperature, diffusion time, and ambient gases were optimized. We observed that the spreading of the P paste was affected by the pyramidal size of the textured wafer due to the low viscosity of the P paste. The pyramidal height of the textured silicon surface was optimized at 3 μm to counterbalance the surface reflectance and the spreading of the P paste. The short-circuit current density of the completed selective emitter solar cell was increased, and an improvement of blue response in the internal quantum efficiency was seen while contact properties such as the fill factor deteriorated due to the spreading of the P paste and the thin emitter on top of the pyramid of the textured silicon surface. Double printing of the P paste was applied to solve this contact problem; a fill factor improvement of 2.4% was obtained.

  18. Selective-emitter crystalline silicon solar cells using phosphorus paste

    Science.gov (United States)

    Jeong, Kyung Taek; Kang, Min Gu; Song, Hee-eun

    2014-11-01

    Selective-emitter structures have been studied to improve the conversion efficiency of crystalline silicon solar cells. However, such structures require additional complicated processes and incur extra cost. In this work, we used phosphorus paste (P-paste) to form a heavily-doped region beneath the grid and POCl3 to create a shallow emitter area. This method should be convenient to use in the solar-cell industry because it requires only additional P paste printing, compared to the case of homogeneous solar cells. Diffusion parameters including the temperature, diffusion time, and ambient gases were optimized. We observed that the spreading of the P paste was affected by the pyramidal size of the textured wafer due to the low viscosity of the P paste. The pyramidal height of the textured silicon surface was optimized at 3 μm to counterbalance the surface reflectance and the spreading of the P paste. The short-circuit current density of the completed selective emitter solar cell was increased, and an improvement of blue response in the internal quantum efficiency was seen while contact properties such as the fill factor deteriorated due to the spreading of the P paste and the thin emitter on top of the pyramid of the textured silicon surface. Double printing of the P paste was applied to solve this contact problem; a fill factor improvement of 2.4% was obtained.

  19. Cooperative Tin Oxide Fullerene Electron Selective Layers for High-Performance Planar Perovskite Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Ke, Weijun; Zhao, Dewei; Xiao, Chuanxiao; Wang, Changlei; Cimaroli, Alexander J.; Grice, Corey R.; Yang, Mengjin; Li, Zhen; Jiang, Chun-Sheng; Al-Jassim, Mowafak; Zhu, Kai; Kanatzidis, Mercouri G.; Fang, Guojia; Yan, Yanfa

    2016-10-07

    Both tin oxide (SnO2) and fullerenes have been reported as electron selective layers (ESLs) for producing efficient lead halide perovskite solar cells. Here, we report that SnO2 and fullerenes can work cooperatively to further boost the performance of perovskite solar cells. We find that fullerenes can be redissolved during perovskite deposition, allowing ultra-thin fullerenes to be retained at the interface and some dissolved fullerenes infiltrate into perovskite grain boundaries. The SnO2 layer blocks holes effectively; whereas, the fullerenes promote electron transfer and passivate both the SnO2/perovskite interface and perovskite grain boundaries. With careful device optimization, the best-performing planar perovskite solar cell using a fullerene passivated SnO2 ESL has achieved a steady-state efficiency of 17.75% and a power conversion efficiency of 19.12% with an open circuit voltage of 1.12 V, a short-circuit current density of 22.61 mA cm-2, and a fill factor of 75.8% when measured under reverse voltage scanning. We find that the partial dissolving of fullerenes during perovskite deposition is the key for fabricating high-performance perovskite solar cells based on metal oxide/fullerene ESLs.

  20. Newcastle disease virus selectively kills human tumor cells.

    Science.gov (United States)

    Reichard, K W; Lorence, R M; Cascino, C J; Peeples, M E; Walter, R J; Fernando, M B; Reyes, H M; Greager, J A

    1992-05-01

    Newcastle disease virus (NDV), strain 73-T, has previously been shown to be cytolytic to mouse tumor cells. In this study, we have evaluated the ability of NDV to replicate in and kill human tumor cells in culture and in athymic mice. Plaque assays were used to determine the cytolytic activity of NDV on six human tumor cell lines, fibrosarcoma (HT1080), osteosarcoma (KHOS), cervical carcinoma (KB8-5-11), bladder carcinoma (HCV29T), neuroblastoma (IMR32), and Wilm's tumor (G104), and on nine different normal human fibroblast lines. NDV formed plaques on all tumor cells tested as well as on chick embryo cells (CEC), the native host for NDV. Plaques did not form on any of the normal fibroblast lines. To detect NDV replication, virus yield assays were performed which measured virus particles in infected cell culture supernatants. Virus yield increased 10,000-fold within 24 hr in tumor and CEC supernatants. Titers remained near zero in normal fibroblast supernatants. In vivo tumoricidal activity was evaluated in athymic nude Balb-c mice by subcutaneous injection of 9 x 10(6) tumor cells followed by intralesional injection of either live or heat-killed NDV (1.0 x 10(6) plaque forming units [PFU]), or medium. After live NDV treatment, tumor regression occurred in 10 out of 11 mice bearing KB8-5-11 tumors, 8 out of 8 with HT-1080 tumors, and 6 out of 7 with IMR-32 tumors. After treatment with heat-killed NDV no regression occurred (P less than 0.01, Fisher's exact test). Nontumor-bearing mice injected with 1.0 x 10(8) PFU of NDV remained healthy. These results indicate that NDV efficiently and selectively replicates in and kills tumor cells, but not normal cells, and that intralesional NDV causes complete tumor regression in athymic mice with a high therapeutic index.

  1. Selective Interlayers and Contacts in Organic Photovoltaic Cells.

    Science.gov (United States)

    Ratcliff, Erin L; Zacher, Brian; Armstrong, Neal R

    2011-06-01

    Organic photovoltaic cells (OPVs) are promising solar electric energy conversion systems with impressive recent optimization of active layers. OPV optimization must now be accompanied by the development of new charge-selective contacts and interlayers. This Perspective considers the role of interface science in energy harvesting using OPVs, looking back at early photoelectrochemical (photogalvanic) energy conversion platforms, which suffered from a lack of charge carrier selectivity. We then examine recent platforms and the fundamental aspects of selective harvesting of holes and electrons at opposite contacts. For blended heterojunction OPVs, contact/interlayer design is especially critical because charge harvesting competes with recombination at these same contacts. New interlayer materials can modify contacts to both control work function and introduce selectivity and chemical compatibility with nonpolar active layers and add thermodynamic and kinetic selectivity to charge harvesting. We briefly discuss the surface and interface science required for the development of new interlayer materials and take a look ahead at the challenges yet to be faced in their optimization. PMID:26295432

  2. Blocking autophagic flux enhances matrine-induced apoptosis in human hepatoma cells.

    Science.gov (United States)

    Wang, Li; Gao, Chun; Yao, Shukun; Xie, Bushan

    2013-11-25

    Autophagy, a self-defense mechanism, has been found to be associated with drug resistance in hepatocellular carcinoma (HCC). Our study was designed to investigate the role and related mechanisms of autophagy in matrine-induced apoptosis in hepatoma cells of HepG2 and Bel7402. Cell apoptosis was detected by flow cytometry analysis (Annexin V-FITC/PI double-staining assay), the activity and activating cleavages of caspase-3, -8, and -9. MTT assay and colony forming assay were used to assess the effect of matrine on growth and proliferation of HCC cells. Autophagic flux in HCC cells was analyzed using the expression of LC3BI/II and p62/SQSTM1, GFP-LC3 transfection, and transmission electron microscopy. Moreover, regarding to the associated mechanisms, the effects of matrine on the phosphoinositide 3-kinase/AKT/mTOR pathway and beclin-1 were studied. Our results showed that: (1) both autophagy and apoptosis could be induced by treatment with matrine; (2) using the autophagic inhibitor chloroquine and beclin-1 small-interfering RNA, cell apoptosis induced by matrine could be enhanced in a caspase-dependent manner; and (3) autophagy was induced via inhibition of PI3K/AKT/mTOR pathway and up-regulation of beclin-1. In conclusion, inhibition of autophagy could enhance matrine-induced apoptosis in human hepatoma cells.

  3. Blocking Autophagic Flux Enhances Matrine-Induced Apoptosis in Human Hepatoma Cells

    Directory of Open Access Journals (Sweden)

    Li Wang

    2013-11-01

    Full Text Available Autophagy, a self-defense mechanism, has been found to be associated with drug resistance in hepatocellular carcinoma (HCC. Our study was designed to investigate the role and related mechanisms of autophagy in matrine-induced apoptosis in hepatoma cells of HepG2 and Bel7402. Cell apoptosis was detected by flow cytometry analysis (Annexin V–FITC/PI double-staining assay, the activity and activating cleavages of caspase-3, -8, and -9. MTT assay and colony forming assay were used to assess the effect of matrine on growth and proliferation of HCC cells. Autophagic flux in HCC cells was analyzed using the expression of LC3BI/II and p62/SQSTM1, GFP-LC3 transfection, and transmission electron microscopy. Moreover, regarding to the associated mechanisms, the effects of matrine on the phosphoinositide 3-kinase/AKT/mTOR pathway and beclin-1 were studied. Our results showed that: (1 both autophagy and apoptosis could be induced by treatment with matrine; (2 using the autophagic inhibitor chloroquine and beclin-1 small-interfering RNA, cell apoptosis induced by matrine could be enhanced in a caspase-dependent manner; and (3 autophagy was induced via inhibition of PI3K/AKT/mTOR pathway and up-regulation of beclin-1. In conclusion, inhibition of autophagy could enhance matrine-induced apoptosis in human hepatoma cells.

  4. Collateral methotrexate resistance in cisplatin-selected murine leukemia cells

    Directory of Open Access Journals (Sweden)

    Bhushan A.

    1999-01-01

    Full Text Available Resistance to anticancer drugs is a major cause of failure of many therapeutic protocols. A variety of mechanisms have been proposed to explain this phenomenon. The exact mechanism depends upon the drug of interest as well as the tumor type treated. While studying a cell line selected for its resistance to cisplatin we noted that the cells expressed a >25,000-fold collateral resistance to methotrexate. Given the magnitude of this resistance we elected to investigate this intriguing collateral resistance. From a series of investigations we have identified an alteration in a membrane protein of the resistant cell as compared to the sensitive cells that could be the primary mechanism of resistance. Our studies reviewed here indicate decreased tyrosine phosphorylation of a protein (molecular mass = 66 in the resistant cells, which results in little or no transfer of methotrexate from the medium into the cell. Since this is a relatively novel function for tyrosine phosphorylation, this information may provide insight into possible pharmacological approaches to modify therapeutic regimens by analyzing the status of this protein in tumor samples for a better survival of the cancer patients.

  5. A group-specific inhibitor of lysosomal cysteine proteinases selectively inhibits both proteolytic degradation and presentation of the antigen dinitrophenyl-poly-L-lysine by guinea pig accessory cells to T cells

    DEFF Research Database (Denmark)

    Buus, S; Werdelin, O

    1986-01-01

    A limited intralysosomal proteolytic degradation is probably a key event in the accessory cell processing of large protein antigens before their presentation to T cells. With the aid of highly specific inhibitors of proteinases, we have examined the role of proteolysis in the presentation of anti...... inhibitor. Another inhibitor, pepstatin A, which selectively blocks aspartic proteinases, did not block the presentation of dinitrophenyl-poly-L-lysine. The results identify cysteine proteinases, probably lysosomal, as one of the groups of enzymes involved in antigen processing....

  6. Squalamine and cisplatin block angiogenesis and growth of human ovarian cancer cells with or without HER-2 gene overexpression.

    Science.gov (United States)

    Li, Dan; Williams, Jon I; Pietras, Richard J

    2002-04-25

    Angiogenesis is important for growth and progression of ovarian cancers. Squalamine is a natural antiangiogenic sterol, and its potential role in treatment of ovarian cancers with or without standard cisplatin chemotherapy was assessed. Since HER-2 gene overexpression is associated with cisplatin resistance in vitro and promotion of tumor angiogenesis in vivo, the response of ovarian cancer cells with or without HER-2 gene overexpression to squalamine and cisplatin was evaluated both in tumor xenograft models and in tissue culture. Ovarian cancer cells with or without HER-2 overexpression were grown as subcutaneous xenografts in nude mice. Animals were treated by intraperitoneal injection with control vehicle, cisplatin, squalamine or cisplatin combined with squalamine. At the end of the experiment, tumors were assessed for tumor growth inhibition and for changes in microvessel density and apoptosis. Additional in vitro studies evaluated effects of squalamine on tumor and endothelial cell growth and on signaling pathways in human endothelial cells. Profound growth inhibition was elicited by squalamine alone and by combined treatment with squalamine and cisplatin for both parental and HER-2-overexpressing ovarian tumor xenografts. Immunohistochemical evaluation of tumors revealed decreased microvessel density and increased apoptosis. Although HER-2-overexpressing tumors had more angiogenic and less apoptotic activity than parental cancers, growth of both tumor types was similarly suppressed by treatment with squalamine combined with cisplatin. In in vitro studies, we found that squalamine does not directly affect proliferation of ovarian cells. However, squalamine significantly blocked VEGF-induced activation of MAP kinase and cell proliferation in human vascular endothelial cells. The results suggest that squalamine is anti-angiogenic for ovarian cancer xenografts and appears to enhance cytotoxic effects of cisplatin chemotherapy independent of HER-2 tumor status

  7. Characterization of Rat Hair Follicle Stem Cells Selected by Vario Magnetic Activated Cell Sorting System

    International Nuclear Information System (INIS)

    Hair follicle stem cells (HfSCs) play crucial roles in hair follicle morphogenesis and hair cycling. These stem cells are self-renewable and have the multi-lineage potential to generate epidermis, sebaceous glands, and hair follicle. The separation and identification of hair follicle stem cells are important for further research in stem cell biology. In this study, we report on the successful enrichment of rat hair follicle stem cells through vario magnetic activated cell sorting (Vario MACS) and the biological characteristics of the stem cells. We chose the HfSCs positive surface markers CD34, α6-integrin and the negative marker CD71 to design four isolation strategies: positive selection with single marker of CD34, positive selection with single marker of α6-integrin, CD71 depletion followed by CD34 positive selection, and CD71 depletion followed by α6-integrin positive selection. The results of flow cytometry analysis showed that all four strategies had ideal effects. Specifically, we conducted a series of researches on HfSCs characterized by their high level of CD34, termed CD34bri cells, and low to undetectable expression of CD34, termed CD34dim cells. CD34bri cells had greater proliferative potential and higher colony-forming ability than CD34dim cells. Furthermore, CD34bri cells had some typical characteristics as progenitor cells, such as large nucleus, obvious nucleolus, large nuclear:cytoplasmic ratio and few cytoplasmic organelles. Our findings clearly demonstrated that HfSCs with high purity and viability could be successfully enriched with Vario MACS

  8. Targeting the PDGF-B/PDGFR-β Interface with Destruxin A5 to Selectively Block PDGF-BB/PDGFR-ββ Signaling and Attenuate Liver Fibrosis

    Directory of Open Access Journals (Sweden)

    Xingqi Wang

    2016-05-01

    Full Text Available PDGF-BB/PDGFR-ββ signaling plays very crucial roles in the process of many diseases such as liver fibrosis. However, drug candidates with selective affinities for PDGF-B/PDGFR-β remain deficient. Here, we identified a natural cyclopeptide termed destruxin A5 that effectively inhibits PDGF-BB-induced PDGFR-β signaling. Interestingly and importantly, the inhibitory mechanism is distinct from the mechanism of tyrosine kinase inhibitors because destruxin A5 does not have the ability to bind to the ATP-binding pocket of PDGFR-β. Using Biacore T200 technology, thermal shift technology, microscale thermophoresis technology and computational analysis, we confirmed that destruxin A5 selectively targets the PDGF-B/PDGFR-β interaction interface to block this signaling. Additionally, the inhibitory effect of destruxin A5 on PDGF-BB/PDGFR-ββ signaling was verified using in vitro, ex vivo and in vivo models, in which the extent of liver fibrosis was effectively alleviated by destruxin A5. In summary, destruxin A5 may represent an efficacious and more selective inhibitor of PDGF-BB/PDGFR-ββ signaling.

  9. Syrbactin Structural Analog TIR-199 Blocks Proteasome Activity and Induces Tumor Cell Death.

    Science.gov (United States)

    Bachmann, André S; Opoku-Ansah, John; Ibarra-Rivera, Tannya R; Yco, Lisette P; Ambadi, Sudhakar; Roberts, Christopher C; Chang, Chia-En A; Pirrung, Michael C

    2016-04-15

    Multiple myeloma is an aggressive hematopoietic cancer of plasma cells. The recent emergence of three effective FDA-approved proteasome-inhibiting drugs, bortezomib (Velcade®), carfilzomib (Kyprolis®), and ixazomib (Ninlaro®), confirms that proteasome inhibitors are therapeutically useful against neoplastic disease, in particular refractory multiple myeloma and mantle cell lymphoma. This study describes the synthesis, computational affinity assessment, and preclinical evaluation of TIR-199, a natural product-derived syrbactin structural analog. Molecular modeling and simulation suggested that TIR-199 covalently binds each of the three catalytic subunits (β1, β2, and β5) and revealed key interaction sites. In vitro and cell culture-based proteasome activity measurements confirmed that TIR-199 inhibits the proteasome in a dose-dependent manner and induces tumor cell death in multiple myeloma and neuroblastoma cells as well as other cancer types in the NCI-60 cell panel. It is particularly effective against kidney tumor cell lines, with >250-fold higher anti-tumor activities than observed with the natural product syringolin A. In vivo studies in mice revealed a maximum tolerated dose of TIR-199 at 25 mg/kg. The anti-tumor activity of TIR-199 was confirmed in hollow fiber assays in mice. Adverse drug reaction screens in a kidney panel revealed no off-targets of concern. This is the first study to examine the efficacy of a syrbactin in animals. Taken together, the results suggest that TIR-199 is a potent new proteasome inhibitor with promise for further development into a clinical drug for the treatment of multiple myeloma and other forms of cancer.

  10. A Novel Peptide to Treat Oral Mucositis Blocks Endothelial and Epithelial Cell Apoptosis

    Energy Technology Data Exchange (ETDEWEB)

    Wu Xiaoyan; Chen Peili [Department of Medicine, University of Chicago, Chicago, Illinois (United States); Sonis, Stephen T. [Division of Oral Medicine, Brigham and Women' s Hospital, Boston, Massachusetts (United States); Biomodels, Watertown, Massachusetts (United States); Lingen, Mark W. [Department of Pathology, University of Chicago, Chicago, Illinois (United States); Berger, Ann [NephRx Corporation, Kalamazoo, Michigan (United States); Toback, F. Gary, E-mail: gtoback@medicine.bsd.uchicago.edu [Department of Medicine, University of Chicago, Chicago, Illinois (United States)

    2012-07-01

    Purpose: No effective agents currently exist to treat oral mucositis (OM) in patients receiving chemoradiation for the treatment of head-and-neck cancer. We identified a novel 21-amino acid peptide derived from antrum mucosal protein-18 that is cytoprotective, mitogenic, and motogenic in tissue culture and animal models of gastrointestinal epithelial cell injury. We examined whether administration of antrum mucosal protein peptide (AMP-p) could protect against and/or speed recovery from OM. Methods and Materials: OM was induced in established hamster models by a single dose of radiation, fractionated radiation, or fractionated radiation together with cisplatin to simulate conventional treatments of head-and-neck cancer. Results: Daily subcutaneous administration of AMP-p reduced the occurrence of ulceration and accelerated mucosal recovery in all three models. A delay in the onset of erythema after irradiation was observed, suggesting that a protective effect exists even before injury to mucosal epithelial cells occurs. To test this hypothesis, the effects of AMP-p on tumor necrosis factor-{alpha}-induced apoptosis were studied in an endothelial cell line (human dermal microvascular endothelial cells) as well as an epithelial cell line (human adult low-calcium, high-temperature keratinocytes; HaCaT) used to model the oral mucosa. AMP-p treatment, either before or after cell monolayers were exposed to tumor necrosis factor-{alpha}, protected against development of apoptosis in both cell types when assessed by annexin V and propidium iodide staining followed by flow cytometry or ligase-mediated polymerase chain reaction. Conclusions: These observations suggest that the ability of AMP-p to attenuate radiation-induced OM could be attributable, at least in part, to its antiapoptotic activity.

  11. Colloidal Alumina-bonded TiB2 Coating on Cathode Carbon Blocks in Aluminum Cells

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Self-propagating high-temperature synthesis (SHS) with reduction process was used to fabricate TiB2 powder from TiO2-B2O3-Mg system. The colloidal alumina-bonded TiB2 paste was prepared and coated on the cathode carbonblocks. Various properties of the baked paste such as the corrosive resistance, thermal expansion and wettability were tested. Experimental results showed that the colloidal alumina-bonded TiB2 coating could be well wetted by liquid alum inum; and the thermal expansion coefficient of the coated material was 5.8× 10 6 ℃ -1 at 20-1000℃, which was close to that of the traditional anthracite block cathode (4× 10 6 ℃ 1); the electrical resistivity was 8 μΩ·m at 900℃ when the con tent of alumina in the coated material was about 9% in mass fraction. In addition, some other good results such as sodium resistance were also reported.

  12. BAFF promotes regulatory T-cell apoptosis and blocks cytokine production by activating B cells in primary biliary cirrhosis

    Directory of Open Access Journals (Sweden)

    Bo Zhang

    2013-10-01

    Full Text Available Primary biliary cirrhosis (PBC is a chronic and slowly progressive cholestatic liver disease of autoimmune etiology. A number of questions regarding its etiology are unclear. CD4+CD25+ regulatory T cells (Tregs play a critical role in self-tolerance and, for unknown reasons, their relative number is reduced in PBC patients. B-cell-activating factor (BAFF is a key survival factor during B-cell maturation and its concentration is increased in peripheral blood of PBC patients. It has been reported that activated B cells inhibit Treg cell proliferation and there are no BAFF receptors on Tregs. Therefore, we speculated that excessive BAFF may result in Treg reduction via B cells. To prove our hypothesis, we isolated Tregs and B cells from PBC and healthy donors. BAFF and IgM concentrations were then analyzed by ELISA and CD40, CD80, CD86, IL-10, and TGF-β expression in B cells and Tregs were measured by flow cytometry. BAFF up-regulated CD40, CD80, CD86, and IgM expression in B cells. However, BAFF had no direct effect on Treg cell apoptosis and cytokine secretion. Nonetheless, we observed that BAFF-activated B cells could induce Treg cell apoptosis and reduce IL-10 and TGF-β expression. We also showed that BAFF-activated CD4+ T cells had no effect on Treg apoptosis. Furthermore, we verified that bezafibrate, a hypolipidemic drug, can inhibit BAFF-induced Treg cell apoptosis. In conclusion, BAFF promotes Treg cell apoptosis and inhibits cytokine production by activating B cells in PBC patients. The results of this study suggest that inhibition of BAFF activation is a strategy for PBC treatment.

  13. BAFF promotes regulatory T-cell apoptosis and blocks cytokine production by activating B cells in primary biliary cirrhosis

    Directory of Open Access Journals (Sweden)

    Bo Zhang

    2013-05-01

    Full Text Available Primary biliary cirrhosis (PBC is a chronic and slowly progressive cholestatic liver disease of autoimmune etiology. A number of questions regarding its etiology are unclear. CD4+CD25+ regulatory T cells (Tregs play a critical role in self-tolerance and, for unknown reasons, their relative number is reduced in PBC patients. B-cell-activating factor (BAFF is a key survival factor during B-cell maturation and its concentration is increased in peripheral blood of PBC patients. It has been reported that activated B cells inhibit Treg cell proliferation and there are no BAFF receptors on Tregs. Therefore, we speculated that excessive BAFF may result in Treg reduction via B cells. To prove our hypothesis, we isolated Tregs and B cells from PBC and healthy donors. BAFF and IgM concentrations were then analyzed by ELISA and CD40, CD80, CD86, IL-10, and TGF-β expression in B cells and Tregs were measured by flow cytometry. BAFF up-regulated CD40, CD80, CD86, and IgM expression in B cells. However, BAFF had no direct effect on Treg cell apoptosis and cytokine secretion. Nonetheless, we observed that BAFF-activated B cells could induce Treg cell apoptosis and reduce IL-10 and TGF-β expression. We also showed that BAFF-activated CD4+ T cells had no effect on Treg apoptosis. Furthermore, we verified that bezafibrate, a hypolipidemic drug, can inhibit BAFF-induced Treg cell apoptosis. In conclusion, BAFF promotes Treg cell apoptosis and inhibits cytokine production by activating B cells in PBC patients. The results of this study suggest that inhibition of BAFF activation is a strategy for PBC treatment.

  14. BAFF promotes regulatory T-cell apoptosis and blocks cytokine production by activating B cells in primary biliary cirrhosis

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Bo; Hu, Mintao [Department of Hepatology, Wuxi Infectious Diseases Hospital, Wuxi, Jiangsu (China); Zhang, Peng [Nanjing Medical University, Nanjing, Jiangsu (China); Cao, Hong [Department of Hepatology, Wuxi Infectious Diseases Hospital, Wuxi, Jiangsu (China); Wang, Yongzhen [The Second Hospital of Nanjing, Nanjing, Jiangsu (China); Wang, Zheng; Su, Tingting [Department of Hepatology, Wuxi Infectious Diseases Hospital, Wuxi, Jiangsu (China)

    2013-05-10

    Primary biliary cirrhosis (PBC) is a chronic and slowly progressive cholestatic liver disease of autoimmune etiology. A number of questions regarding its etiology are unclear. CD4+CD25+ regulatory T cells (Tregs) play a critical role in self-tolerance and, for unknown reasons, their relative number is reduced in PBC patients. B-cell-activating factor (BAFF) is a key survival factor during B-cell maturation and its concentration is increased in peripheral blood of PBC patients. It has been reported that activated B cells inhibit Treg cell proliferation and there are no BAFF receptors on Tregs. Therefore, we speculated that excessive BAFF may result in Treg reduction via B cells. To prove our hypothesis, we isolated Tregs and B cells from PBC and healthy donors. BAFF and IgM concentrations were then analyzed by ELISA and CD40, CD80, CD86, IL-10, and TGF-β expression in B cells and Tregs were measured by flow cytometry. BAFF up-regulated CD40, CD80, CD86, and IgM expression in B cells. However, BAFF had no direct effect on Treg cell apoptosis and cytokine secretion. Nonetheless, we observed that BAFF-activated B cells could induce Treg cell apoptosis and reduce IL-10 and TGF-β expression. We also showed that BAFF-activated CD4+ T cells had no effect on Treg apoptosis. Furthermore, we verified that bezafibrate, a hypolipidemic drug, can inhibit BAFF-induced Treg cell apoptosis. In conclusion, BAFF promotes Treg cell apoptosis and inhibits cytokine production by activating B cells in PBC patients. The results of this study suggest that inhibition of BAFF activation is a strategy for PBC treatment.

  15. BAFF promotes regulatory T-cell apoptosis and blocks cytokine production by activating B cells in primary biliary cirrhosis

    International Nuclear Information System (INIS)

    Primary biliary cirrhosis (PBC) is a chronic and slowly progressive cholestatic liver disease of autoimmune etiology. A number of questions regarding its etiology are unclear. CD4+CD25+ regulatory T cells (Tregs) play a critical role in self-tolerance and, for unknown reasons, their relative number is reduced in PBC patients. B-cell-activating factor (BAFF) is a key survival factor during B-cell maturation and its concentration is increased in peripheral blood of PBC patients. It has been reported that activated B cells inhibit Treg cell proliferation and there are no BAFF receptors on Tregs. Therefore, we speculated that excessive BAFF may result in Treg reduction via B cells. To prove our hypothesis, we isolated Tregs and B cells from PBC and healthy donors. BAFF and IgM concentrations were then analyzed by ELISA and CD40, CD80, CD86, IL-10, and TGF-β expression in B cells and Tregs were measured by flow cytometry. BAFF up-regulated CD40, CD80, CD86, and IgM expression in B cells. However, BAFF had no direct effect on Treg cell apoptosis and cytokine secretion. Nonetheless, we observed that BAFF-activated B cells could induce Treg cell apoptosis and reduce IL-10 and TGF-β expression. We also showed that BAFF-activated CD4+ T cells had no effect on Treg apoptosis. Furthermore, we verified that bezafibrate, a hypolipidemic drug, can inhibit BAFF-induced Treg cell apoptosis. In conclusion, BAFF promotes Treg cell apoptosis and inhibits cytokine production by activating B cells in PBC patients. The results of this study suggest that inhibition of BAFF activation is a strategy for PBC treatment

  16. Protein-engineered block-copolymers as stem cell delivery vehicles

    Science.gov (United States)

    Heilshorn, Sarah

    2015-03-01

    Stem cell transplantation is a promising therapy for a myriad of debilitating diseases and injuries; however, current delivery protocols are inadequate. Transplantation by direct injection, which is clinically preferred for its minimal invasiveness, commonly results in less than 5% cell viability, greatly inhibiting clinical outcomes. We demonstrate that mechanical membrane disruption results in significant acute loss of viability at clinically relevant injection rates. As a strategy to protect cells from these damaging forces, we show that cell encapsulation within hydrogels of specific mechanical properties will significantly improve viability. Building on these fundamental studies, we have designed a reproducible, bio-resorbable, customizable hydrogel using protein-engineering technology. In our Mixing-Induced Two-Component Hydrogel (MITCH), network assembly is driven by specific and stoichiometric peptide-peptide binding interactions. By integrating protein science methodologies with simple polymer physics models, we manipulate the polypeptide chain interactions and demonstrate the direct ability to tune the network crosslinking density, sol-gel phase behavior, and gel mechanics. This is in contrast to many other physical hydrogels, where predictable tuning of bulk mechanics from the molecular level remains elusive due to the reliance on non-specific and non-stoichiometric chain interactions for network formation. Furthermore, the hydrogel network can be easily modified to deliver a variety of bioactive payloads including growth factors, peptide drugs, and hydroxyapatite nanoparticles. Through a series of in vitro and in vivo studies, we demonstrate that these materials may significantly improve transplanted stem cell retention and function.

  17. ID4 promotes AR expression and blocks tumorigenicity of PC3 prostate cancer cells.

    Science.gov (United States)

    Komaragiri, Shravan Kumar; Bostanthirige, Dhanushka H; Morton, Derrick J; Patel, Divya; Joshi, Jugal; Upadhyay, Sunil; Chaudhary, Jaideep

    2016-09-01

    Deregulation of tumor suppressor genes is associated with tumorigenesis and the development of cancer. In prostate cancer, ID4 is epigenetically silenced and acts as a tumor suppressor. In normal prostate epithelial cells, ID4 collaborates with androgen receptor (AR) and p53 to exert its tumor suppressor activity. Previous studies have shown that ID4 promotes tumor suppressive function of AR whereas loss of ID4 results in tumor promoter activity of AR. Previous study from our lab showed that ectopic ID4 expression in DU145 attenuates proliferation and promotes AR expression suggesting that ID4 dependent AR activity is tumor suppressive. In this study, we examined the effect of ectopic expression of ID4 on highly malignant prostate cancer cell, PC3. Here we show that stable overexpression of ID4 in PC3 cells leads to increased apoptosis and decreased cell proliferation and migration. In addition, in vivo studies showed a decrease in tumor size and volume of ID4 overexpressing PC3 cells, in nude mice. At the molecular level, these changes were associated with increased androgen receptor (AR), p21, and AR dependent FKBP51 expression. At the mechanistic level, ID4 may regulate the expression or function of AR through specific but yet unknown AR co-regulators that may determine the final outcome of AR function. PMID:27462022

  18. Dexamethasone blocks arachidonate biosynthesis in isolated hepatocytes and cultured hepatoma cells

    International Nuclear Information System (INIS)

    The effect of dexamethasone on the incorporation and conversion of [1-14C]eicosa-8,11,14-trienoic acid to arachidonic acid in isolated hepatocytes and in hepatoma tissue culture (HTC) cells was studied. In both kinds of cells, no changes in the exogenous acid incorporation were found when the hormone was added to the incubation media at 0.1 or 0.2 mM concentration, while the biosynthesis of arachidonic acid was significantly depressed. The effect on the biosynthesis was faster in isolated normal liver cells (60 min) than in tumoral cells (120 min) and reached an inhibition of ca. 50% after 3 hr of treatment. The addition of cycloheximide (10(-6) M) also caused a marked decrease in the biosynthesis of this polyunsaturated fatty acid, but when dexamethasone was added to the media simultaneously with cycloheximide, a synergistic action was not observed. The results obtained show that protein synthesis would be involved in the modulation of the biosynthesis of arachidonic acid by glucocorticoids. The changes in the delta 5 desaturation of labeled 20:3 omega 6 to arachidonic acid correlated with changes in the fatty acid composition in isolated cells

  19. Large Stokes shift downshifting Eu(III) films as efficiency enhancing UV blocking layers for dye sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Kennedy, M.; Ahmed, H.; Doran, J.; Norton, B. [Dublin Energy Laboratory, Dublin Institute of Technology (Ireland); Bosch-Jimenez, P.; Della Pirriera, M.; Torralba-Calleja, E.; Gutierrez Tauste, D.; Aubouy, L. [Leitat Technological Center, Terrassa (Spain); Daren, S.; Solomon-Tsvetkov, F. [Daren Laboratories, Ness-Ziona (Israel); Galindo, S.; Voz, C.; Puigdollers, J. [Universitat Politecnica Catalunya, Barcelona (Spain)

    2015-01-01

    Large Stokes shift downshifting organolanthanide complex, Eu(tta){sub 3}phen, is examined for inclusion in polymeric layers to replace the UV blocking layer in dye sensitized solar cell (DSSC) technology. The UV blocking layer increases stability but power conversion efficiency decreases as incident UV photons are not converted into photocurrent. Eu(tta){sub 3}phen doped polymeric film are prepared and attached to DSSC devices following optimized thickness and concentration from a ray-trace numerical model for the specific DSSC. External quantum efficiency is significantly increased in the UV spectral region compared to DSSCs utilizing a passive, non-luminescent, UV-BL. High Eu(tta){sub 3}phen film transparency in the visible range minimizes DSSC EQE losses at visible wavelengths. Short-circuit current (I{sub sc}) enhancement due to downshifting is demonstrated (∝1%) in small-scale DSSC prototypes, where the specific geometry limits the photon collection efficiency and overall enhancement. Model predictions indicate that 2%-3% Isc enhancement is realizable in flexible single DSSC compared to, non-luminescent, UV-BL. Added to this, in outdoor conditions taking into account diffuse light, the increment in I{sub sc} can increase 50% more. Although photostability of the blended LSS-DS polymer films is not sufficient to be useful for medium-long term outdoor PV applications, the results demonstrate that significant efficiency enhancement can be realized. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Improved conductivity in dye-sensitised solar cells through block-copolymer confined TiO 2 crystallisation

    KAUST Repository

    Guldin, Stefan

    2011-01-01

    Anatase TiO2 is typically a central component in high performance dye-sensitised solar cells (DSCs). This study demonstrates the benefits of high temperature synthesised mesoporous titania for the performance of solid-state DSCs. In contrast to earlier methods, the high temperature stability of mesoporous titania is enabled by the self-assembly of the amphiphilic block copolymer polyisoprene-block-polyethylene oxide (PI-b -PEO) which compartmentalises TiO2 crystallisation, preventing the collapse of porosity at temperatures up to 700 °C. The systematic study of the temperature dependence on DSC performance reveals a parameter trade-off: high temperature annealed anatase consisted of larger crystallites and had a higher conductivity, but this came at the expense of a reduced specific surface area. While the reduction in specific surface areas was found to be detrimental for liquid-electrolyte DSC performance, solid-state DSCs benefitted from the increased anatase conductivity and exhibited a performance increase by a factor of three. © 2011 The Royal Society of Chemistry.

  1. Increasing intracellular bioavailable copper selectively targets prostate cancer cells.

    Science.gov (United States)

    Cater, Michael A; Pearson, Helen B; Wolyniec, Kamil; Klaver, Paul; Bilandzic, Maree; Paterson, Brett M; Bush, Ashley I; Humbert, Patrick O; La Fontaine, Sharon; Donnelly, Paul S; Haupt, Ygal

    2013-07-19

    The therapeutic efficacy of two bis(thiosemicarbazonato) copper complexes, glyoxalbis[N4-methylthiosemicarbazonato]Cu(II) [Cu(II)(gtsm)] and diacetylbis[N4-methylthiosemicarbazonato]Cu(II) [Cu(II)(atsm)], for the treatment of prostate cancer was assessed in cell culture and animal models. Distinctively, copper dissociates intracellularly from Cu(II)(gtsm) but is retained by Cu(II)(atsm). We further demonstrated that intracellular H2gtsm [reduced Cu(II)(gtsm)] continues to redistribute copper into a bioavailable (exchangeable) pool. Both Cu(II)(gtsm) and Cu(II)(atsm) selectively kill transformed (hyperplastic and carcinoma) prostate cell lines but, importantly, do not affect the viability of primary prostate epithelial cells. Increasing extracellular copper concentrations enhanced the therapeutic capacity of both Cu(II)(gtsm) and Cu(II)(atsm), and their ligands (H2gtsm and H2atsm) were toxic only toward cancerous prostate cells when combined with copper. Treatment of the Transgenic Adenocarcinoma of Mouse Prostate (TRAMP) model with Cu(II)(gtsm) (2.5 mg/kg) significantly reduced prostate cancer burden (∼70%) and severity (grade), while treatment with Cu(II)(atsm) (30 mg/kg) was ineffective at the given dose. However, Cu(II)(gtsm) caused mild kidney toxicity in the mice, associated primarily with interstitial nephritis and luminal distention. Mechanistically, we demonstrated that Cu(II)(gtsm) inhibits proteasomal chymotrypsin-like activity, a feature further established as being common to copper-ionophores that increase intracellular bioavailable copper. We have demonstrated that increasing intracellular bioavailable copper can selectively kill cancerous prostate cells in vitro and in vivo and have revealed the potential for bis(thiosemicarbazone) copper complexes to be developed as therapeutics for prostate cancer.

  2. Nobiletin inhibits human osteosarcoma cells metastasis by blocking ERK and JNK-mediated MMPs expression

    Science.gov (United States)

    Cheng, Hsin-Lin; Hsieh, Ming-Ju; Yang, Jia-Sin; Lin, Chiao-Wen; Lue, Ko-Haung; Lu, Ko-Hsiu; Yang, Shun-Fa

    2016-01-01

    Nobiletin, a polymethoxyflavone, has a few pharmacological activities, including anti-inflammation and anti-cancer effects. However, its effect on human osteosarcoma progression remains uninvestigated. Therefore, we examined the effectiveness of nobiletin against cellular metastasis of human osteosarcoma and the underlying mechanisms. Nobiletin, up to 100 μM without cytotoxicity, significantly decreased motility, migration and invasion as well as enzymatic activities, protein levels and mRNA expressions of matrix metalloproteinase (MMP)-2 and MMP-9 in U2OS and HOS cells. In addition to inhibition of extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK), the inhibitory effect of nobiletin on the DNA-binding activity of the transcription factor nuclear factor-kappa B (NF-κB), cAMP response element-binding protein (CREB), and specificity protein 1 (SP-1) in U2OS and HOS cells. Co-treatment with ERK and JNK inhibitors and nobiletin further reduced U2OS cells migration and invasion. These results indicated that nobiletin inhibits human osteosarcoma U2OS and HOS cells motility, migration and invasion by down-regulating MMP-2 and MMP-9 expressions via ERK and JNK pathways and through the inactivation of downstream NF-κB, CREB, and SP-1. Nobiletin has the potential to serve as an anti-metastatic agent for treating osteosarcoma. PMID:27144433

  3. Curdlan blocks the immune suppression by myeloid-derived suppressor cells and reduces tumor burden.

    Science.gov (United States)

    Rui, Ke; Tian, Jie; Tang, Xinyi; Ma, Jie; Xu, Ping; Tian, Xinyu; Wang, Yungang; Xu, Huaxi; Lu, Liwei; Wang, Shengjun

    2016-08-01

    Tumor-elicited immunosuppression is one of the essential mechanisms for tumor evasion of immune surveillance. It is widely thought to be one of the main reasons for the failure of tumor immunotherapy. Myeloid-derived suppressor cells (MDSCs) comprise a heterogeneous population of cells that play an important role in tumor-induced immunosuppression. These cells expand in tumor-bearing individuals and suppress T cell responses via various mechanisms. Curdlan, the linear (1 → 3)-β-glucan from Agrobacterium, has been applied in the food industry and other sectors. The anti-tumor property of curdlan has been recognized for a long time although the underlying mechanism still needs to be explored. In this study, we investigated the effect of curdlan on MDSCs and found that curdlan could promote MDSCs to differentiate into a more mature state and then significantly reduce the suppressive function of MDSCs, decrease the MDSCs in vivo and down-regulate the suppression in tumor-bearing mice, thus leading to enhanced anti-tumor immune responses. We, therefore, increase the understanding of further mechanisms by which curdlan achieves anti-tumor effects. PMID:26832917

  4. Differential programming of p53-deficient embryonic cells during rotenone block

    Science.gov (United States)

    Mitochondrial dysfunction has been implicated in chemical toxicities. The present study used an in vitro model to investigate the differential expression of metabolic pathways during cellular stress in p53- efficient embryonic fibroblasts compared to p53-deficient cells. These c...

  5. The V protein of Tioman virus is incapable of blocking type I interferon signaling in human cells.

    Directory of Open Access Journals (Sweden)

    Grégory Caignard

    Full Text Available The capacity of a virus to cross species barriers is determined by the development of bona fide interactions with cellular components of new hosts, and in particular its ability to block IFN-α/β antiviral signaling. Tioman virus (TioV, a close relative of mumps virus (MuV, has been isolated in giant fruit bats in Southeast Asia. Nipah and Hendra viruses, which are present in the same bat colonies, are highly pathogenic in human. Despite serological evidences of close contacts between TioV and human populations, whether TioV is associated to some human pathology remains undetermined. Here we show that in contrast to the V protein of MuV, the V protein of TioV (TioV-V hardly interacts with human STAT2, does not degrade STAT1, and cannot block IFN-α/β signaling in human cells. In contrast, TioV-V properly binds to human STAT3 and MDA5, and thus interferes with IL-6 signaling and IFN-β promoter induction in human cells. Because STAT2 binding was previously identified as a host restriction factor for some Paramyxoviridae, we established STAT2 sequence from giant fruit bats, and binding to TioV-V was tested. Surprisingly, TioV-V interaction with STAT2 from giant fruit bats is also extremely weak and barely detectable. Altogether, our observations question the capacity of TioV to appropriately control IFN-α/β signaling in both human and giant fruit bats that are considered as its natural host.

  6. The state of cell block variation and satisfaction in the era of molecular diagnostics and personalized medicine

    Directory of Open Access Journals (Sweden)

    John P Crapanzano

    2014-01-01

    Full Text Available Background: In the recent past, algorithms and recommendations to standardize the morphological, immunohistochemical and molecular classification of lung cancers on cytology specimens have been proposed, and several organizations have recommended cell blocks (CBs as the preferred modality for molecular testing. Based on the literature, there are several different techniques available for CB preparation-suggesting that there is no standard. The aim of this study was to conduct a survey of CB preparation techniques utilized in various practice settings and analyze current issues, if any. Materials and Methods: A single E-mail with a link to an electronic survey was distributed to members of the American Society of Cytopathology and other pathologists. Questions pertaining to the participants′ practice setting and CBs-volume, method, quality and satisfaction-were included. Results: Of 95 respondents, 90/95 (94% completed the survey and comprise the study group. Most participants practice in a community hospital/private practice (44% or academic center (41%. On average, 14 CBs (range 0-50; median 10 are prepared by a laboratory daily. Over 10 methods are utilized: Plasma thrombin (33%, HistoGel (27%, Cellient automated cell block system (8% and others (31% respectively. Forty of 90 (44% respondents are either unsatisfied or sometimes satisfied with their CB quality, with low-cellular yield being the leading cause of dissatisfaction. There was no statistical significance between the three most common CB preparation methods and satisfaction with quality. Discussion: Many are dissatisfied with their current method of CB preparation, and there is no consistent method to prepare CBs. In today′s era of personalized medicine with an increasing array of molecular tests being applied to cytological specimens, there is a need for a standardized protocol for CB optimization to enhance cellularity.

  7. Cold atmospheric plasma treatment selectively targets head and neck squamous cell carcinoma cells.

    Science.gov (United States)

    Guerrero-Preston, Rafael; Ogawa, Takenori; Uemura, Mamoru; Shumulinsky, Gary; Valle, Blanca L; Pirini, Francesca; Ravi, Rajani; Sidransky, David; Keidar, Michael; Trink, Barry

    2014-10-01

    The treatment of locoregional recurrence (LRR) of head and neck squamous cell carcinoma (HNSCC) often requires a combination of surgery, radiation therapy and/or chemotherapy. Survival outcomes are poor and the treatment outcomes are morbid. Cold atmospheric plasma (CAP) is an ionized gas produced at room temperature under laboratory conditions. We have previously demonstrated that treatment with a CAP jet device selectively targets cancer cells using in vitro melanoma and in vivo bladder cancer models. In the present study, we wished to examine CAP selectivity in HNSCC in vitro models, and to explore its potential for use as a minimally invasive surgical approach that allows for specific cancer cell or tumor tissue ablation without affecting the surrounding healthy cells and tissues. Four HNSCC cell lines (JHU-022, JHU-028, JHU-029, SCC25) and 2 normal oral cavity epithelial cell lines (OKF6 and NOKsi) were subjected to cold plasma treatment for durations of 10, 30 and 45 sec, and a helium flow of 20 l/min-1 for 10 sec was used as a positive treatment control. We showed that cold plasma selectively diminished HNSCC cell viability in a dose-response manner, as evidenced by MTT assays; the viability of the OKF6 cells was not affected by the cold plasma. The results of colony formation assays also revealed a cell-specific response to cold plasma application. Western blot analysis did not provide evidence that the cleavage of PARP occurred following cold plasma treatment. In conclusion, our results suggest that cold plasma application selectively impairs HNSCC cell lines through non-apoptotic mechanisms, while having a minimal effect on normal oral cavity epithelial cell lines.

  8. Serial block face-scanning electron microscopy: a tool for studying embryonic development at the cell-matrix interface.

    Science.gov (United States)

    Starborg, Tobias; Kadler, Karl E

    2015-03-01

    Studies of gene regulation, signaling pathways, and stem cell biology are contributing greatly to our understanding of early embryonic vertebrate development. However, much less is known about the events during the latter half of embryonic development, when tissues comprising mostly extracellular matrix (ECM) are formed. The matrix extends far beyond the boundaries of individual cells and is refractory to study by conventional biochemical and molecular techniques; thus major gaps exist in our knowledge of the formation and three-dimensional (3D) organization of the dense tissues that form the bulk of adult vertebrates. Serial block face-scanning electron microscopy (SBF-SEM) has the ability to image volumes of tissue containing numerous cells at a resolution sufficient to study the organization of the ECM. Furthermore, whereas light microscopy was once relatively straightforward and electron microscopy was performed in specialist laboratories, the tables are turned; SBF-SEM is relatively straightforward and is becoming routine in high-end resolution studies of embryonic structures in vivo. In this review, we discuss the emergence of SBF-SEM as a tool for studying embryonic vertebrate development.

  9. Design, synthesis, and in vitro and in vivo biological studies of a 3'-deoxythymidine conjugate that potentially kills cancer cells selectively.

    Directory of Open Access Journals (Sweden)

    Qiong Wei

    Full Text Available Thymidine kinases (TKs have been considered one of the potential targets for anticancer therapeutic because of their elevated expressions in cancer cells. However, nucleobase analogs targeting TKs have shown poor selective cytotoxicity in cancer cells despite effective antiviral activity. 3'-Deoxythymidine phenylquinoxaline conjugate (dT-QX was designed as a novel nucleobase analog to target TKs in cancer cells and block cell replication via conjugated DNA intercalating quinoxaline moiety. In vitro cell screening showed that dT-QX selectively kills a variety of cancer cells including liver carcinoma, breast adenocarcinoma and brain glioma cells; whereas it had a low cytotoxicity in normal cells such as normal human liver cells. The anticancer activity of dT-QX was attributed to its selective inhibition of DNA synthesis resulting in extensive mitochondrial superoxide stress in cancer cells. We demonstrate that covalent linkage with 3'-deoxythymidine uniquely directed cytotoxic phenylquinoxaline moiety more toward cancer cells than normal cells. Preliminary mouse study with subcutaneous liver tumor model showed that dT-QX effectively inhibited the growth of tumors. dT-QX is the first molecule of its kind with highly amendable constituents that exhibits this selective cytotoxicity in cancer cells.

  10. Block copolymer based composition and morphology control in nanostructured hybrid materials for energy conversion and storage: solar cells, batteries, and fuel cells

    KAUST Repository

    Orilall, M. Christopher

    2011-01-01

    The development of energy conversion and storage devices is at the forefront of research geared towards a sustainable future. However, there are numerous issues that prevent the widespread use of these technologies including cost, performance and durability. These limitations can be directly related to the materials used. In particular, the design and fabrication of nanostructured hybrid materials is expected to provide breakthroughs for the advancement of these technologies. This tutorial review will highlight block copolymers as an emerging and powerful yet affordable tool to structure-direct such nanomaterials with precise control over structural dimensions, composition and spatial arrangement of materials in composites. After providing an introduction to materials design and current limitations, the review will highlight some of the most recent examples of block copolymer structure-directed nanomaterials for photovoltaics, batteries and fuel cells. In each case insights are provided into the various underlying fundamental chemical, thermodynamic and kinetic formation principles enabling general and relatively inexpensive wet-polymer chemistry methodologies for the efficient creation of multiscale functional materials. Examples include nanostructured ceramics, ceramic-carbon composites, ceramic-carbon-metal composites and metals with morphologies ranging from hexagonally arranged cylinders to three-dimensional bi-continuous cubic networks. The review ends with an outlook towards the synthesis of multicomponent and hierarchical multifunctional hybrid materials with different nano-architectures from self-assembly of higher order blocked macromolecules which may ultimately pave the way for the further development of energy conversion and storage devices. © 2011 The Royal Society of Chemistry.

  11. A novel electronic current-blocked stable mixed ionic conductor for solid oxide fuel cells

    NARCIS (Netherlands)

    Sun, Wenping; Jiang, Yinzhu; Wang, Yanfei; Fang, Shumin; Zhu, Zhiwen; Liu, Wei

    2011-01-01

    A novel ionic conductor, BaCe0.8Sm0.2O3−δ–Ce0.8Sm0.2O2−δ (BCS–SDC, weight ratio 1:1), is reported as an electrolyte material for solid oxide fuel cells (SOFCs). Homogeneous BCS–SDC composite powders are synthesized via a one-step gel combustion method. The BCS and SDC crystalline grains play a role

  12. B Cell-Specific S1PR1 Deficiency Blocks Prion Dissemination between Secondary Lymphoid Organs

    OpenAIRE

    Mok, S. W.; Proia, R L; Brinkmann, V; Mabbott, N A

    2012-01-01

    Many prion diseases are peripherally acquired (e.g., orally or via lesions to skin or mucous membranes). After peripheral exposure, prions replicate first upon follicular dendritic cells (FDC) in the draining lymphoid tissue before infecting the brain. However, after replication upon FDC within the draining lymphoid tissue, prions are subsequently propagated to most nondraining secondary lymphoid organs (SLO), including the spleen, by a previously underdetermined mechanism. The germinal cente...

  13. ING1 and 5-Azacytidine Act Synergistically to Block Breast Cancer Cell Growth

    OpenAIRE

    Satbir Thakur; Xiaolan Feng; Zhong Qiao Shi; Amudha Ganapathy; Manoj Kumar Mishra; Peter Atadja; Don Morris; Karl Riabowol

    2012-01-01

    BACKGROUND: Inhibitor of Growth (ING) proteins are epigenetic "readers" that recognize trimethylated lysine 4 of histone H3 (H3K4Me3) and target histone acetyl transferase (HAT) and histone deacetylase (HDAC) complexes to chromatin. METHODS AND PRINCIPAL FINDINGS: Here we asked whether dysregulating two epigenetic pathways with chemical inhibitors showed synergistic effects on breast cancer cell line killing. We also tested whether ING1 could synergize better with chemotherapeutics that targe...

  14. Prolonged tamoxifen exposure selects a breast cancer cell clone that is stable in vitro and in vivo.

    Science.gov (United States)

    Sipila, P E; Wiebe, V J; Hubbard, G B; Koester, S K; Emshoff, V D; Maenpaa, J U; Wurz, G T; Seymour, R C; DeGregorio, M W

    1993-01-01

    The effects of long-term tamoxifen exposure on cell growth and cell cycle kinetics were compared between oestrogen receptor (ER)-positive (MCF-7) and ER-negative (MDA-MB-231) cell lines. In the MCF-7 cell line, prolonged tamoxifen exposure (0.5 mumol/l for > 100 days) blocked cells in G0-G1 of the cell cycle, and slowed the doubling time of cells from 30 to 59 h. These effects corresponded to an increase in the cellular accumulation of tamoxifen over time [mean area under concentration curve (AUC) = 77.92 mumoles/10(6)/cells/day]. In contrast, in the MDA-MB-231 cell line, long-term tamoxifen exposure had no obvious effect on the doubling time, and reduced cellular tamoxifen accumulation (mean AUC = 50.50 mumoles/10(6)/cells/day) compared to the MCF-7 cells. Flow cytometric analysis of MDA-MB-231 cells demonstrated that a new tetraploid clone emerged following 56 days of tamoxifen exposure. Inoculation of the MDA-MB-231 tetraploid clone and MDA-MB-231 wildtype cells into the opposite flanks of athymic nude mice resulted in the rapid growth of tetraploid tumours. The tetraploid tumours maintained their ploidy following tamoxifen treatment for nine consecutive serial transplantations. Histological examination of the fifth transplant generation xenografts revealed that the tetraploid tumour had a 25-30 times greater mass, area of haemorrhage and necrosis, a slightly higher mitotic index and was more anaplastic than the control neoplasm. The control wildtype MDA-MB-231 tumours maintained a stable ploidy following tamoxifen treatment until the eighth and ninth transplantation, when a tetraploid population appeared, suggesting that tamoxifen treatment may select for this clone in vivo. These studies suggest that prolonged tamoxifen exposure may select for new, stable, fast growing cell clones in vitro as well as in vivo. PMID:8297653

  15. MUC1 in human milk blocks transmission of human immunodeficiency virus from dendritic cells to T cells

    NARCIS (Netherlands)

    Saeland, E.; Jong, de M.A.W.P.; Nabatov, A.; Kalay, H.; Kooijk, van Y.; Geijtenbeek, T.B.H.

    2009-01-01

    Mother-to-child transmission of human immunodeficiency virus-1 (HIV-1) occurs frequently via breast-feeding. HIV-1 targets DC-SIGN+ dendritic cells (DCs) in mucosal areas that allow efficient transmission of the virus to T cells. Here, we demonstrate that the epithelial mucin MUC1, abundant in milk,

  16. Influences of alcoholic solvents on spray pyrolysis deposition of TiO2 blocking layer films for solid-state dye-sensitized solar cells

    International Nuclear Information System (INIS)

    Influences of alcoholic solvents for titanium diisopropoxide bis(acetylacetonate) (TPA) precursor solutions on the spray pyrolysis deposited TiO2 films and the photovoltaic performance of the solid-state dye-sensitized solar cells (SDSCs) using these TiO2 films as the blocking layers were investigated. Smooth TiO2 films were obtained by spray pyrolysis deposition of a TPA solution in isopropanol (IPA) at a relatively low temperature of 260 °C. On the other hand, when ethanol was used as solvent, the TiO2 films fabricated at the same temperature showed much rougher surfaces with many pinholes. Our results showed that ethanol reacts with TPA to form titanium diethoxide bis(acetylacetonate) (TEA), which requires a higher thermal decomposition temperature than that of TPA. SDSCs with TiO2 blocking layer films fabricated using a TPA solution in IPA showed higher power conversion efficiencies with smaller variations. - Graphical abstract: Alcoholic solvents used for the TiO2 precursor play a critical role in determining the surface morphology of blocking layers and thus the photovoltaic performance of the SDSCs. Highlights: ► Solvent influences morphology of spray pyrolysis deposited TiO2 blocking layer. ► Ethanol reacts with TPA, resulting poor quality of blocking layer. ► Isopropanol is better than ethanol for obtaining smooth blocking layer. ► SDSC with blocking layer made with isopropanol showed better performance.

  17. Pan-Bcl-2 inhibitor obatoclax delays cell cycle progression and blocks migration of colorectal cancer cells.

    Directory of Open Access Journals (Sweden)

    Bruno Christian Koehler

    Full Text Available Despite the fact that new treatment regimes have improved overall survival of patients challenged by colorectal cancer (CRC, prognosis in the metastatic situation is still restricted. The Bcl-2 family of proteins has been identified as promising anti cancer drug target. Even though small molecules targeting Bcl-2 proteins are in clinical trials, little is known regarding their effects on CRC. The aim of this study was to preclinically investigate the value of ABT-737 and Obatoclax as anticancer drugs for CRC treatment. The effects of the BH3-mimetics ABT-737 and Obatoclax on CRC cells were assessed using viability and apoptosis assays. Wound healing migration and boyden chamber invasion assays were applied. 3-dimensional cell cultures were used for long term assessment of invasion and proliferation. Clinically relevant concentrations of pan-Bcl-2 inhibitor Obatoclax did not induce cell death. In contrast, the BH3-mimetic ABT-737 induced apoptosis in a dose dependent manner. Obatoclax caused a cell line specific slowdown of CRC cell growth. Furthermore, Obatoclax, but not ABT-737, recovered E-Cadherin expression and led to impaired migration and invasion of CRC cells. The proliferative capacity and invasiveness of CRC cells was strikingly inhibited by low dose Obatoclax in long term 3-dimensional cell cultures. Obatoclax, but not ABT-737, caused a G1-phase arrest accompanied by a downregulation of Cyclin D1 and upregulation of p27 and p21. Overexpression of Mcl-1, Bcl-xL or Bcl-2 reversed the inhibitory effect of Obatoclax on migration but failed to restore the proliferative capacity of Obatoclax-treated CRC cells. The data presented indicate broad and multifaceted antitumor effects of the pan-Bcl-2 inhibitor Obatoclax on CRC cells. In contrast to ABT-737, Obatoclax inhibited migration, invasion and proliferation in sublethal doses. In summary, this study recommends pan-Bcl-2 inhibition as a promising approach for clinical trials in CRC.

  18. Selective migration of neuralized embryonic stem cells to stem cell factor and media conditioned by glioma cell lines

    Directory of Open Access Journals (Sweden)

    Maria Bernard L

    2006-01-01

    Full Text Available Abstract Background Pluripotent mouse embryonic stem (ES cells can be induced in vitro to become neural progenitors. Upon transplantation, neural progenitors migrate toward areas of damage and inflammation in the CNS. We tested whether undifferentiated and neuralized mouse ES cells migrate toward media conditioned by glioma cell lines (C6, U87 & N1321 or Stem Cell Factor (SCF. Results Cell migration assays revealed selective migration by neuralized ES cells to conditioned media as well as to synthetic SCF. Migration of undifferentiated ES cells was extensive, but not significantly different from that of controls (Unconditioned Medium. RT-PCR analysis revealed that all the three tumor cell lines tested synthesized SCF and that both undifferentiated and neuralized ES cells expressed c-kit, the receptor for SCF. Conclusion Our results demonstrate that undifferentiated ES cells are highly mobile and that neural progenitors derived from ES cells are selectively attracted toward factors produced by gliomas. Given that the glioma cell lines synthesize SCF, SCF may be one of several factors that contribute to the selective migration observed.

  19. Selective migration of neuralized embryonic stem cells to stem cell factor and media conditioned by glioma cell lines

    Science.gov (United States)

    Serfozo, Peter; Schlarman, Maggie S; Pierret, Chris; Maria, Bernard L; Kirk, Mark D

    2006-01-01

    Background Pluripotent mouse embryonic stem (ES) cells can be induced in vitro to become neural progenitors. Upon transplantation, neural progenitors migrate toward areas of damage and inflammation in the CNS. We tested whether undifferentiated and neuralized mouse ES cells migrate toward media conditioned by glioma cell lines (C6, U87 & N1321) or Stem Cell Factor (SCF). Results Cell migration assays revealed selective migration by neuralized ES cells to conditioned media as well as to synthetic SCF. Migration of undifferentiated ES cells was extensive, but not significantly different from that of controls (Unconditioned Medium). RT-PCR analysis revealed that all the three tumor cell lines tested synthesized SCF and that both undifferentiated and neuralized ES cells expressed c-kit, the receptor for SCF. Conclusion Our results demonstrate that undifferentiated ES cells are highly mobile and that neural progenitors derived from ES cells are selectively attracted toward factors produced by gliomas. Given that the glioma cell lines synthesize SCF, SCF may be one of several factors that contribute to the selective migration observed. PMID:16436212

  20. The G-protein-coupled estrogen receptor agonist G-1 suppresses proliferation of ovarian cancer cells by blocking tubulin polymerization

    OpenAIRE

    Wang, C; Lv, X.; C. He; Hua, G; Tsai, M-Y; Davis, J S

    2013-01-01

    The G-protein-coupled estrogen receptor 1 (GPER) has recently been reported to mediate the non-genomic action of estrogen in different types of cells and tissues. G-1 (1-[4-(6-bromobenzo[1,3] dioxol-5yl)-3a,4,5,9b-tetrahydro-3H-cyclopenta[c]quinolin-8-yl]-ethanone) was developed as a potent and selective agonist for GPER. G-1 has been shown to induce the expression of genes and activate pathways that facilitate cancer cell proliferation by activating GPER. Here we demonstrate that G-1 has an ...

  1. Primary cardiac B-cell lymphoma with atrioventricular block and paroxysmal ventricular tachycardia

    Directory of Open Access Journals (Sweden)

    Chen Ke-Wei

    2012-07-01

    Full Text Available Abstract Primary cardiac lymphoma (PCL is very rare, and is extremely challenging to diagnose due to nonspecific symptoms. When discovered, the right atrium and ventricle are most commonly affected, while diffuse cardiac involvement is uncommon. PCL is fatal unless promptly diagnosed and treated. Herein, we present the case of a 36-year-old immunocompetent male who presented with a 5-year history of non-specific chest symptoms and was diagnosed with primary diffuse cardiac large B-cell lymphoma involving the entire heart.

  2. Wood-fired fuel cells in selected buildings

    Science.gov (United States)

    McIlveen-Wright, D. R.; McMullan, J. T.; Guiney, D. J.

    of selected buildings in rural areas, with regard to the high cost of importing other fuel, and/or lack of grid electricity, could still make these systems attractive options. Any economic analysis of these systems is beset with severe difficulties. Capital costs of the major system components are not known with any great precision. However, a guideline assessment of the payback period for such CHP systems was made. When the best available capital costs for system components were used, most of these systems were found to have unacceptably long payback periods, particularly where the fuel cell lifetimes are short, but the larger systems show the potential for a reasonable economic return.

  3. Medium Renewal Blocks Anti-Proliferative Effects of Metformin in Cultured MDA-MB-231 Breast Cancer Cells.

    Directory of Open Access Journals (Sweden)

    Maruša Rajh

    Full Text Available Epidemiological studies indicate that metformin, a widely used type 2 diabetes drug, might reduce breast cancer risk and mortality in patients with type 2 diabetes. Metformin might protect against breast cancer indirectly by ameliorating systemic glucose homeostasis. Alternatively, it might target breast cancer cells directly. However, experiments using MDA-MB-231 cells, a standard in vitro breast cancer model, produced inconsistent results regarding effectiveness of metformin as a direct anti-cancer agent. Metformin treatments in cultured MDA-MB-231 cells are usually performed for 48-96 hours, but protocols describing renewal of cell culture medium during these prolonged treatments are rarely reported. We determined whether medium renewal protocol might alter sensitivity of MDA-MB-231 cells treated with metformin. Using the MTS assay, BrdU incorporation and Hoechst staining we found that treatment with metformin for 48-72 hours failed to suppress viability and proliferation of MDA-MB-231 cells if low-glucose (1 g/L medium was renewed every 24 hours. Conversely, metformin suppressed their viability and proliferation if medium was not renewed. Without renewal glucose concentration in the medium was reduced to 0.1 g/L in 72 hours, which likely explains increased sensitivity to metformin under these conditions. We also examined whether 2-deoxy-D-glucose (2-DG reduces resistance to metformin. In the presence of 2-DG metformin reduced viability and proliferation of MDA-MB-231 cells with or without medium renewal, thus demonstrating that 2-DG reduces their resistance to metformin. In sum, we show that medium renewal blocks anti-proliferative effects of metformin during prolonged treatments in low-glucose medium. Differences in medium renewal protocols during prolonged treatments might therefore lead to apparently inconsistent results as regards effectiveness of metformin as a direct anti-cancer agent. Finally, our results indicate that co-therapy with

  4. Medium Renewal Blocks Anti-Proliferative Effects of Metformin in Cultured MDA-MB-231 Breast Cancer Cells.

    Science.gov (United States)

    Rajh, Maruša; Dolinar, Klemen; Miš, Katarina; Pavlin, Mojca; Pirkmajer, Sergej

    2016-01-01

    Epidemiological studies indicate that metformin, a widely used type 2 diabetes drug, might reduce breast cancer risk and mortality in patients with type 2 diabetes. Metformin might protect against breast cancer indirectly by ameliorating systemic glucose homeostasis. Alternatively, it might target breast cancer cells directly. However, experiments using MDA-MB-231 cells, a standard in vitro breast cancer model, produced inconsistent results regarding effectiveness of metformin as a direct anti-cancer agent. Metformin treatments in cultured MDA-MB-231 cells are usually performed for 48-96 hours, but protocols describing renewal of cell culture medium during these prolonged treatments are rarely reported. We determined whether medium renewal protocol might alter sensitivity of MDA-MB-231 cells treated with metformin. Using the MTS assay, BrdU incorporation and Hoechst staining we found that treatment with metformin for 48-72 hours failed to suppress viability and proliferation of MDA-MB-231 cells if low-glucose (1 g/L) medium was renewed every 24 hours. Conversely, metformin suppressed their viability and proliferation if medium was not renewed. Without renewal glucose concentration in the medium was reduced to 0.1 g/L in 72 hours, which likely explains increased sensitivity to metformin under these conditions. We also examined whether 2-deoxy-D-glucose (2-DG) reduces resistance to metformin. In the presence of 2-DG metformin reduced viability and proliferation of MDA-MB-231 cells with or without medium renewal, thus demonstrating that 2-DG reduces their resistance to metformin. In sum, we show that medium renewal blocks anti-proliferative effects of metformin during prolonged treatments in low-glucose medium. Differences in medium renewal protocols during prolonged treatments might therefore lead to apparently inconsistent results as regards effectiveness of metformin as a direct anti-cancer agent. Finally, our results indicate that co-therapy with 2-DG and

  5. Molecular recognition of CYP26A1 binding pockets and structure-activity relationship studies for design of potent and selective retinoic acid metabolism blocking agents.

    Science.gov (United States)

    Sun, Bin; Song, Shuai; Hao, Chen-Zhou; Huang, Wan-Xu; Liu, Chun-Chi; Xie, Hong-Lei; Lin, Bin; Cheng, Mao-Sheng; Zhao, Dong-Mei

    2015-03-01

    All-trans-retinoic acid (ATRA), the biologically most active metabolite of vitamin A, plays a major role in the regulation of cellular differentiation and proliferation, and it is also an important pharmacological agent particularly used in the treatment of cancer, skin, neurodegenerative and autoimmune diseases. However, ATRA is very easy to be metabolized into 4-hydroxyl-RA in vivo by CYP26A1, an inducible cytochrome P450 enzyme, eventually into more polar metabolites. Therefore, it is vital to develop specific retinoic acid metabolism blocking agents (RAMBAs) to inhibit the metabolic enzyme CYP26A1 in the treatment of relevant diseases aforementioned. In this study, CYP26A1 and its interactions with retinoic acid-competitive metabolism blocking agents were investigated by a combined ligand- and structure-based approach. First, since the crystal structure of CYP26A1 protein has not been determined, we constructed the 3D structure of CYP26A1 using homology modeling. In order to achieve a deeper insight into the mode of action of RAMBAs in the active site, the molecular superimposition model and the common feature pharmacophore model were constructed, and molecular docking was performed. The molecular superimposition model is composed of three features: the main chain groups, side chain groups, and azole groups. The common feature pharmacophore model consists of five chemical features: four hydrophobic groups and one hydrogen acceptor (HHHHA). The results of molecular docking show that the characteristic groups of RAMBAs were mapped into three different active pockets, respectively. A structure-activity relationship (SAR) was obtained by a combination of the molecular superimposition and docking results with the pharmacophore model. This study gives more insight into the interaction model inside the CYP26A1 active site and provides guidance for the design of more potent and possibly more selective RAMBAs.

  6. Targeted suppression of autoreactive CD8+ T-cell activation using blocking anti-CD8 antibodies

    Science.gov (United States)

    Clement, Mathew; Pearson, James A.; Gras, Stephanie; van den Berg, Hugo A.; Lissina, Anya; Llewellyn-Lacey, Sian; Willis, Mark D.; Dockree, Tamsin; McLaren, James E.; Ekeruche-Makinde, Julia; Gostick, Emma; Robertson, Neil P.; Rossjohn, Jamie; Burrows, Scott R.; Price, David A.; Wong, F. Susan; Peakman, Mark; Skowera, Ania; Wooldridge, Linda

    2016-01-01

    CD8+ T-cells play a role in the pathogenesis of autoimmune diseases such as multiple sclerosis and type 1 diabetes. However, drugs that target the entire CD8+ T-cell population are not desirable because the associated lack of specificity can lead to unwanted consequences, most notably an enhanced susceptibility to infection. Here, we show that autoreactive CD8+ T-cells are highly dependent on CD8 for ligand-induced activation via the T-cell receptor (TCR). In contrast, pathogen-specific CD8+ T-cells are relatively CD8-independent. These generic differences relate to an intrinsic dichotomy that segregates self-derived and exogenous antigen-specific TCRs according to the monomeric interaction affinity with cognate peptide-major histocompatibility complex class I (pMHCI). As a consequence, “blocking” anti-CD8 antibodies can suppress autoreactive CD8+ T-cell activation in a relatively selective manner. These findings provide a rational basis for the development and in vivo assessment of novel therapeutic strategies that preferentially target disease-relevant autoimmune responses within the CD8+ T-cell compartment. PMID:27748447

  7. 小鼠孤雌胚2-细胞阻滞的研究%Studies on mouse parthenogenetic embryos 2-cell block

    Institute of Scientific and Technical Information of China (English)

    何志全; 李三华; 陈伟; 陆祥

    2011-01-01

    In order to study the mechanism of mouse parthenogenetic embryos 2-cell block,we selected oviduct epithelial cells and pituitary cells for feeder layer to culture mouse parthenogenetic embryos. The mouse oocytes which were activated after dealing with 5 min in 70mL/L alcohol and 3 h in 2 mmol/L 6- DMAP and 5 g/mL CB, were cultured in KSOM medium containing different feeder layers. We observed and compared mouse parthenogenetic embryos developmental situation which were in various culture conditions. In result,the embryos had no significant difference in each group after 24 h culture,and all of them had high cleavage rate(P〉0. 05). After being cultured to 48 h, the parthenogenetic embryos cultured in KSOM medium with two types of feeder cells had developmental effect of 4 to 8-cell,it was significantly different(P〈0.05) compared with single feeder layer cell and cotrol group(P〈0.01). The ratio of embryos which can develop to Morula/blastocyst was 49.4%(42/85)(P〈0.01). We inferred that KSOM medium containing oviduct epithelial cells and pituitary cells can effectively promote the development of mouse parthenogenetic embryos which can breakthrough 2-cell block(block rate to 74.1%), and further improve embryos development(morula/blastocyst rate to 49.4 %).%为探讨小鼠孤雌胚2-细胞阻滞的机制,本试验以昆明小鼠为研究对象,通过输卵管上皮细胞和垂体细胞作为饲养层培养小鼠孤雌胚胎,分析其作用机理。小鼠卵母细胞通过70mL/L乙醇激活5min,再用2mmol/L 6-DMAP、5μg/mL CB激活3h后,分别在不同饲养层的KSOM培养液中进行培养,观察并比较各培养条件下孤雌胚胎的发育情况。结果,培养至第24小时,各组无显著差异(P〉0.05),都有较高卵裂率。培养至第48小时,用两种饲养层细胞培养的孤雌胚胎4-细胞~8-细胞发育效果好,与用单独一种饲养层细胞培养相比,差异显著(P〈0.05),与对照

  8. Biofunctionalized nanoparticles with pH-responsive and cell penetrating blocks for gene delivery

    Science.gov (United States)

    Gaspar, V. M.; Marques, J. G.; Sousa, F.; Louro, R. O.; Queiroz, J. A.; Correia, I. J.

    2013-07-01

    Bridging the gap between nanoparticulate delivery systems and translational gene therapy is a long sought after requirement in nanomedicine-based applications. However, recent developments regarding nanoparticle functionalization have brought forward the ability to synthesize materials with biofunctional moieties that mimic the evolved features of viral particles. Herein we report the versatile conjugation of both cell penetrating arginine and pH-responsive histidine moieties into the chitosan polymeric backbone, to improve the physicochemical characteristics of the native material. Amino acid coupling was confirmed by 2D TOCSY NMR and Fourier transform infrared spectroscopy. The synthesized chitosan-histidine-arginine (CH-H-R) polymer complexed plasmid DNA biopharmaceuticals, and spontaneously assembled into stable 105 nm nanoparticles with spherical morphology and positive surface charge. The functionalized delivery systems were efficiently internalized into the intracellular compartment, and exhibited remarkably higher transfection efficiency than unmodified chitosan without causing any cytotoxic effect. Additional findings regarding intracellular trafficking events reveal their preferential escape from degradative lysosomal pathways and nuclear localization. Overall, this assembly of nanocarriers with bioinspired moieties provides the foundations for the design of efficient and customizable materials for cancer gene therapy.

  9. Mesenchymal stem cells: building blocks for molecular medicine in the 21st century.

    Science.gov (United States)

    Caplan, A I; Bruder, S P

    2001-06-01

    Mesenchymal stem sells (MSCs) are present in a variety of tissues during human development, and in adults they are prevalent in bone marrow. From that readily available source, MSCs can be isolated, expanded in culture, and stimulated to differentiate into bone, cartilage, muscle, marrow stroma, tendon, fat and a variety of other connective tissues. Because large numbers of MSCs can be generated in culture, tissue-engineered constructs principally composed of these cells could be re-introduced into the in vivo setting. This approach is now being explored to regenerate tissues that the body cannot naturally repair or regenerate when challenged. Moreover, MSCs can be transduced with retroviral and other vectors and are, thus, potential candidates to deliver somatic gene therapies for local or systemic pathologies. Untapped applications include both diagnostic and prognostic uses of MSCs and their descendents in healthcare management. Finally, by understanding the complex, multistep and multifactorial differentiation pathway from MSC to functional tissues, it might be possible to manipulate MSCs directly in vivo to cue the formation of elaborate, composite tissues in situ.

  10. Selective ablation of the androgen receptor in mouse sertoli cells affects sertoli cell maturation, barrier formation and cytoskeletal development.

    Directory of Open Access Journals (Sweden)

    Ariane Willems

    Full Text Available The observation that mice with a selective ablation of the androgen receptor (AR in Sertoli cells (SC (SCARKO mice display a complete block in meiosis supports the contention that SC play a pivotal role in the control of germ cell development by androgens. To delineate the physiological and molecular mechanism responsible for this control, we compared tubular development in pubertal SCARKO mice and littermate controls. Particular attention was paid to differences in SC maturation, SC barrier formation and cytoskeletal organization and to the molecular mediators potentially involved. Functional analysis of SC barrier development by hypertonic perfusion and lanthanum permeation techniques and immunohistochemical analysis of junction formation showed that SCARKO mice still attempt to produce a barrier separating basal and adluminal compartment but that barrier formation is delayed and defective. Defective barrier formation was accompanied by disturbances in SC nuclear maturation (immature shape, absence of prominent, tripartite nucleoli and SC polarization (aberrant positioning of SC nuclei and cytoskeletal elements such as vimentin. Quantitative RT-PCR was used to study the transcript levels of genes potentially related to the described phenomena between day 8 and 35. Differences in the expression of SC genes known to play a role in junction formation could be shown from day 8 for Cldn11, from day 15 for Cldn3 and Espn, from day 20 for Cdh2 and Jam3 and from day 35 for ZO-1. Marked differences were also noted in the transcript levels of several genes that are also related to cell adhesion and cytoskeletal dynamics but that have not yet been studied in SC (Actn3, Ank3, Anxa9, Scin, Emb, Mpzl2. It is concluded that absence of a functional AR in SC impedes the remodeling of testicular tubules expected at the onset of spermatogenesis and interferes with the creation of the specific environment needed for germ cell development.

  11. DA-9601, a standardized extract of Artemisia asiatica, blocks TNF-α-induced IL-8 and CCL20 production by inhibiting p38 kinase and NF-κB pathways in human gastric epithelial cells

    Institute of Scientific and Technical Information of China (English)

    Suck-Chei Choi; Kang-Min Lee; Won-Jung Lee; Jae-Sik Park; Chang-Yell Shin; Tae-Young Oh; Chang-Duk Jun; Eun-Ju Choi; Hyun-Mee Oh; SungGa Lee; Jeong-Kun Lee; Meung-Su Lee; Yong-Il Shin; Suck-Jun Choi; Jeong-Ryong Chae

    2006-01-01

    AIM: To investigate whether, or how, DA-9601, which is a new gastroprotective agent, inhibits TNF-α-induced inflammatory signals in gastric epithelial AGS cells. METHODS: Cell viability was determined by MTT assay. IL-8 and CCL20 promoter activities were determined by a luciferease reporter gene assay. NF-κB-dependent transcriptional activity was determined by I-κBα degradation, NF-κB p65 nuclear translocation and a luciferase activity assay. IL-8 and CCL20 gene expression and protein secretion were determined by RT-PCR and an enzymelinked immunosorbent assay (ELISA). Total and phosphorylated forms of mitogen-activated protein kinases (MAPKs) were determined by Western blot. RESULTS: Treatment of AGS cells with DA-9601 reduced TNF-α-induced IL-8 and CCL20 promoter activities, as well as their gene expression and protein release. TNF-α also induced NF-κB-dependent transcriptional activity in AGS cells. In contrast, in cells treated with DA-9601, TNF-α-induced NF-κB activity was significantly blocked. Although all three MAP kinase family members were phosphorylated in response to TNF-α, a selective inhibitor of p38 kinase SB203580 only could inhibit both NF κB-dependent transcriptional activity and IL-8 and CCL20 production, suggesting a potential link between p38 kinase and NF-κB-dependent pathways in AGS cells. Interestingly, DA-9601 also selectively inhibited p38 kinase phosphorylation induced by TNF-α.CONCLUSION: DA-9601 blocked TNF-α-mediated inflammatory signals by potentially modulating the p38 kinase pathway and/or a signal leading to NF-κB dependent pathways in gastric epithelial cells.

  12. Zitongxi Block

    Institute of Scientific and Technical Information of China (English)

    1996-01-01

    @@ Zitongxi Block (Western Zitong Block), is located in Zitong County, northwest of Sichuan Province (as shown on Fig. 8 ). Geologically. it is situated in the Zitong Depression, southwest of the middle Longmenshan faulted and folded belt, covering an area of 1 830 km2. Transportation is very convenient. A crisscross network of highways run through the block and the Baocheng railway is nearby. The climate is moderate. Most area belongs to hilly land with the elevation of 500-600 m.The Tongjiang River runs across the area.

  13. Selective accumulation of pro-inflammatory T cells in the intestine contributes to the resistance to autoimmune demyelinating disease.

    Directory of Open Access Journals (Sweden)

    Kerstin Berer

    Full Text Available Myelin-specific, pro-inflammatory TH17 cells are widely regarded as the drivers of experimental autoimmune encephalomyelitis (EAE, an animal model for Multiple sclerosis (MS. The factors, responsible for the generation and maintenance of TH17 cells as well as their participation in the pathogenic cascade leading to the demyelinating disease, have been studied extensively. However, how these harmful autoreactive cells are controlled in vivo remains unclear. By comparing TCR transgenic mice on a disease susceptible and a disease resistant genetic background, we show here that pathogenic TH17 cells are sequestered within the intestine of spontaneous EAE resistant B10.S mice. Disease resistant B10.S mice harbored higher frequencies of TH17 cells in the intestine compared to EAE susceptible SJL/J mice. Moreover, transferred TH17 cells selectively migrated to intestinal lymphoid organs of B10.S mice. The sequestration of TH17 cells in the gut was partially dependent on the gut homing receptor α4β7-mediated adhesion to the intestine. Administration of α4β7 blocking-antibodies increased the peripheral availability of TH17 cells, resulting in increased EAE severity after immunization in B10.S mice. Together, these results support the concept that the intestine is a check-point for controlling pathogenic, organ-specific T cells.

  14. Antibodies to P-selectin glycoprotein ligand-1 block dendritic cell-mediated enterovirus 71 transmission and prevent virus-induced cells death.

    Science.gov (United States)

    Ren, Xiao-Xin; Li, Chuan; Xiong, Si-Dong; Huang, Zhong; Wang, Jian-Hua; Wang, Hai-Bo

    2015-01-01

    P-selectin glycoprotein ligand-1 (PSGL-1) has been proved to serve as the functional receptor for enterovirus 71 (EV71). We found the abundant expression of PSGL-1 on monocyte-derived dendritic cells (MDDCs). However, we have previously demonstrated that MDDCs did not support efficient replication of EV71. Dendritic cells (DCs) have been described to be subverted by various viruses including EV71 for viral dissemination, we thus explore the potential contribution of PSGL-1 on DC-mediated EV71 transmission. We found that the cell-surface-expressing PSGL-1 on MDDCs mediated EV71 binding, and intriguingly, these loaded-viruses on MDDCs could be transferred to encountered target cells; Prior-treatment with PSGL-1 antibodies or interference with PSGL-1 expression diminished MDDC-mediated EV71 transfer and rescued virus-induced cell death. Our data uncover a novel role of PSGL-1 in DC-mediated EV71 spread, and provide an insight into blocking primary EV71 infection.

  15. PSC-RANTES blocks R5 human immunodeficiency virus infection of Langerhans cells isolated from individuals with a variety of CCR5 diplotypes.

    Science.gov (United States)

    Kawamura, Tatsuyoshi; Bruse, Shannon E; Abraha, Awet; Sugaya, Makoto; Hartley, Oliver; Offord, Robin E; Arts, Eric J; Zimmerman, Peter A; Blauvelt, Andrew; Bruce, Shannon E

    2004-07-01

    Topical microbicides that effectively block interactions between CCR5(+) immature Langerhans cells (LC) residing within genital epithelia and R5 human immunodeficiency virus (HIV) may decrease sexual transmission of HIV. Here, we investigated the ability of synthetic RANTES analogues (AOP-, NNY-, and PSC-RANTES) to block R5 HIV infection of human immature LC by using a skin explant model. In initial experiments using activated peripheral blood mononuclear cells, each analogue compound demonstrated marked antiviral activity against two R5 HIV isolates. Next, we found that 20-min preincubation of skin explants with each RANTES analogue blocked R5 HIV infection of LC in a dose-dependent manner (1 to 100 nM) and that PSC-RANTES was the most potent of these compounds. Similarly, preincubation of LC with each analogue was able to block LC-mediated infection of cocultured CD4(+) T cells. Competition experiments between primary R5 and X4 HIV isolates showed blocking of R5 HIV by PSC-RANTES and no evidence of increased propagation of X4 HIV, data that are consistent with the specificity of PSC-RANTES for CCR5 and the CCR5(+) CXCR4(-) phenotype of immature LC. Finally, when CCR5 genetic polymorphism data were integrated with results from the in vitro LC infection studies, PSC-RANTES was found to be equally effective in inhibiting R5 HIV in LC isolated from individuals with CCR5 diplotypes known to be associated with low, intermediate, and high cell surface levels of CCR5. In summary, PSC-RANTES is a potent inhibitor of R5 HIV infection in immature LC, suggesting that it may be useful as a topical microbicide to block sexual transmission of HIV.

  16. Interferon gamma blocks the growth of Toxoplasma gondii in human fibroblasts by inducing the host cells to degrade tryptophan.

    Science.gov (United States)

    Pfefferkorn, E R

    1984-01-01

    Treatment of human fibroblasts with human recombinant gamma interferon blocked the growth of Toxoplasma gondii, an obligate intracellular protozoan parasite. Growth of the parasite was measured by a plaque assay 7 days after infection or by the incorporation of [3H]uracil 1 or 2 days after infection. The antitoxoplasma activity induced in the host cells by gamma interferon was strongly dependent upon the tryptophan concentration of the medium. Progressively higher minimal inhibitory concentrations of gamma interferon were observed as the tryptophan concentration in the culture medium was increased. Treatment with gamma interferon did not make the cells impermeable to tryptophan. The kinetics of [3H]tryptophan uptake into the acid-soluble pools of control and gamma interferon-treated cultures were identical during the first 48 sec. Thereafter uptake of [3H]tryptophan into the acid-soluble pool of control fibroblasts reached the expected plateau after 96 sec. In contrast, uptake of [3H]tryptophan continued for at least 12 min in the gamma interferon-treated cultures. At that time, the acid-soluble pool of the gamma interferon-treated cultures contained 8 times the radioactivity of the control cultures. This continued accumulation was the result of rapid intracellular degradation of [3H]tryptophan into kynurenine and N-formylkynurenine that leaked slowly from the cells. These two metabolites were also recovered from the medium of cultures treated for 1 or 2 days with gamma interferon. Human recombinant alpha and beta interferons, which have no antitoxoplasma activity, did not induce any detectable degradation of tryptophan. Several hypotheses are presented to explain how the intracellular degradation of tryptophan induced by gamma interferon could restrict the growth of an obligate intracellular parasite. Images PMID:6422465

  17. (p)ppGpp modulates cell size and the initiation of DNA replication in Caulobacter crescentus in response to a block in lipid biosynthesis.

    Science.gov (United States)

    Stott, Kristina V; Wood, Shannon M; Blair, Jimmy A; Nguyen, Bao T; Herrera, Anabel; Mora, Yannet G Perez; Cuajungco, Math P; Murray, Sean R

    2015-03-01

    Stress conditions, such as a block in fatty acid synthesis, signal bacterial cells to exit the cell cycle. Caulobacter crescentus FabH is a cell-cycle-regulated β-ketoacyl-acyl carrier protein synthase that initiates lipid biosynthesis and is essential for growth in rich media. To explore how C. crescentus responds to a block in lipid biosynthesis, we created a FabH-depletion strain. We found that FabH depletion blocks lipid biosynthesis in rich media and causes a cell cycle arrest that requires the alarmone (p)ppGpp for adaptation. Notably, basal levels of (p)ppGpp coordinate both a reduction in cell volume and a block in the over-initiation of DNA replication in response to FabH depletion. The gene ctrA encodes a master transcription factor that directly regulates 95 cell-cycle-controlled genes while also functioning to inhibit the initiation of DNA replication. Here, we demonstrate that ctrA transcription is (p)ppGpp-dependent during fatty acid starvation. CtrA fails to accumulate when FabH is depleted in the absence of (p)ppGpp due to a substantial reduction in ctrA transcription. The (p)ppGpp-dependent maintenance of ctrA transcription during fatty acid starvation initiated from only one of the two ctrA promoters. In the absence of (p)ppGpp, the majority of FabH-depleted cells enter a viable but non-culturable state, with multiple chromosomes, and are unable to recover from the miscoordination of cell cycle events. Thus, basal levels of (p)ppGpp facilitate C. crescentus' re-entry into the cell cycle after termination of fatty acid starvation.

  18. Effective Application of the Methanol-Based PreservCyt (TM) Fixative and the Cellient (TM) Automated Cell Block Processor to Diagnostic Cytopathology, Immunocytochemistry, and Molecular Biology

    NARCIS (Netherlands)

    van Hemel, Bettien M.; Suurmeijer, Albert J. H.

    2013-01-01

    We studied the feasibility of immunocytochemistry (ICC), in situ hybridization (ISH), and polymerase chain reaction (PCR) after Cellient automated cell block processing, and tested whether methanol-based PreservCyt fixation could replace formalin fixation, in an attempt to eliminate toxic formaldehy

  19. EVIDENCE FOR EXISTENCE OF IMMUNOGLOBULINS THAT BLOCK OVARIAN GRANULOSA-CELL GROWTH-INVITRO - A PUTATIVE ROLE IN RESISTANT OVARY SYNDROME

    NARCIS (Netherlands)

    VANWEISSENBRUCH, MM; HOEK, A; VAN VLIET BLEEKER, I.; SCHOEMAKER, J; DREXHAGE, H

    1991-01-01

    The sera of 26 patients with premature ovarian failure were examined in order to detect immunoglobulin-G (IgGs) that can block FSH-induced in vitro granulosa cell DNA synthesis via, a Feulgen cytochemical bioassay system. The IgGs of four patients with polycystic ovary-like disease, five postmenopau

  20. An Electrochemical Cell for Selective Lithium Capture from Seawater.

    Science.gov (United States)

    Kim, Joo-Seong; Lee, Yong-Hee; Choi, Seungyeon; Shin, Jaeho; Dinh, Hung-Cuong; Choi, Jang Wook

    2015-08-18

    Lithium (Li) is a core element of Li-ion batteries (LIBs). Recent developments in mobile electronics such as smartphones and tablet PCs as well as advent of large-scale LIB applications including electrical vehicles and grid-level energy storage systems have led to an increase in demand for LIBs, giving rise to a concern on the availability and market price of Li resources. However, the current Lime-Soda process that is responsible for greater than 80% of worldwide Li resource supply is applicable only in certain regions on earth where the Li concentrations are sufficiently high (salt lakes or salt pans). Moreover, not only is the process time-consuming (12-18 months), but post-treatments are also required for the purification of Li. Here, we have devised a location-independent electrochemical system for Li capture, which can operate within a short time period (a few hours to days). By engaging olivine LiFePO4 active electrode that improves interfacial properties via polydopamine coating, the electrochemical cell achieves 4330 times amplification in Li/Na ion selectivity (Li/Na molar ratio of initial solution = 0.01 and Li/Na molar ratio of final electrode = 43.3). In addition, the electrochemical system engages an I(-)/I3(-) redox couple in the other electrode for balancing of the redox states on both electrode sides and sustainable operations of the entire cell. Based on the electrochemical results, key material and interfacial properties that affect the selectivity in Li capture are identified. PMID:25920476

  1. Drug Treatment of Cancer Cell Lines: A Way to Select for Cancer Stem Cells?

    International Nuclear Information System (INIS)

    Tumors are generally composed of different cell types. In recent years, it has been shown that in many types of cancers a subset of cells show peculiar characteristics, such as the ability to induce tumors when engrafted into host animals, self-renew and being immortal, and give rise to a differentiated progeny. These cells have been defined as cancer stem cells (CSCs) or tumor initiating cells. CSCs can be isolated both from tumor specimens and established cancer cell lines on the basis of their ability to exclude fluorescent dyes, express specific cell surface markers or grow in particular culture conditions. A key feature of CSCs is their resistance to chemotherapeutic agents, which could contribute to the remaining of residual cancer cells after therapeutic treatments. It has been shown that CSC-like cells can be isolated after drug treatment of cancer cell lines; in this review, we will describe the strategies so far applied to identify and isolate CSCs. Furthermore, we will discuss the possible use of these selected populations to investigate CSC biology and develop new anticancer drugs

  2. Drug Treatment of Cancer Cell Lines: A Way to Select for Cancer Stem Cells?

    Energy Technology Data Exchange (ETDEWEB)

    Chiodi, Ilaria; Belgiovine, Cristina; Donà, Francesca; Scovassi, A. Ivana; Mondello, Chiara, E-mail: mondello@igm.cnr.it [Institute of Molecular Genetics, CNR, via Abbiategrasso 207, 27100 Pavia (Italy)

    2011-03-04

    Tumors are generally composed of different cell types. In recent years, it has been shown that in many types of cancers a subset of cells show peculiar characteristics, such as the ability to induce tumors when engrafted into host animals, self-renew and being immortal, and give rise to a differentiated progeny. These cells have been defined as cancer stem cells (CSCs) or tumor initiating cells. CSCs can be isolated both from tumor specimens and established cancer cell lines on the basis of their ability to exclude fluorescent dyes, express specific cell surface markers or grow in particular culture conditions. A key feature of CSCs is their resistance to chemotherapeutic agents, which could contribute to the remaining of residual cancer cells after therapeutic treatments. It has been shown that CSC-like cells can be isolated after drug treatment of cancer cell lines; in this review, we will describe the strategies so far applied to identify and isolate CSCs. Furthermore, we will discuss the possible use of these selected populations to investigate CSC biology and develop new anticancer drugs.

  3. Drug Treatment of Cancer Cell Lines: A Way to Select for Cancer Stem Cells?

    Directory of Open Access Journals (Sweden)

    Ilaria Chiodi

    2011-03-01

    Full Text Available Tumors are generally composed of different cell types. In recent years, it has been shown that in many types of cancers a subset of cells show peculiar characteristics, such as the ability to induce tumors when engrafted into host animals, self-renew and being immortal, and give rise to a differentiated progeny. These cells have been defined as cancer stem cells (CSCs or tumor initiating cells. CSCs can be isolated both from tumor specimens and established cancer cell lines on the basis of their ability to exclude fluorescent dyes, express specific cell surface markers or grow in particular culture conditions. A key feature of CSCs is their resistance to chemotherapeutic agents, which could contribute to the remaining of residual cancer cells after therapeutic treatments. It has been shown that CSC-like cells can be isolated after drug treatment of cancer cell lines; in this review, we will describe the strategies so far applied to identify and isolate CSCs. Furthermore, we will discuss the possible use of these selected populations to investigate CSC biology and develop new anticancer drugs.

  4. Repair of Ischemic Injury by Pluripotent Stem Cell Based Cell Therapy without Teratoma through Selective Photosensitivity.

    Science.gov (United States)

    Cho, Seung-Ju; Kim, So-Yeon; Jeong, Ho-Chang; Cheong, Hyeonsik; Kim, Doseok; Park, Soon-Jung; Choi, Jong-Jin; Kim, Hyongbum; Chung, Hyung-Min; Moon, Sung-Hwan; Cha, Hyuk-Jin

    2015-12-01

    Stem-toxic small molecules have been developed to induce selective cell death of pluripotent stem cells (PSCs) to lower the risk of teratoma formation. However, despite their high efficacies, chemical-based approaches may carry unexpected toxicities on specific differentiated cell types. Herein, we took advantage of KillerRed (KR) as a suicide gene, to selectively induce phototoxicity using visible light via the production of reactive oxygen species. PSCs in an undifferentiated state that exclusively expressed KR (KR-PSCs) were eliminated by a single exposure to visible light. This highly selective cell death in KR-PSCs was exploited to successfully inhibit teratoma formation. In particular, endothelial cells from KR-mPSCs remained fully functional in vitro and sufficient to repair ischemic injury in vivo regardless of light exposure, suggesting that a genetic approach in which KR is expressed in a tightly controlled manner would be a viable strategy to inhibit teratoma formation for future safe PSC-based therapies.

  5. Nourseothricin N-acetyl transferase: a positive selection marker for mammalian cells.

    Directory of Open Access Journals (Sweden)

    Bose S Kochupurakkal

    Full Text Available Development of Nourseothricin N-acetyl transferase (NAT as a selection marker for mammalian cells is described. Mammalian cells are acutely susceptible to Nourseothricin, similar to the widely used drug Puromycin, and NAT allows for quick and robust selection of transfected/transduced cells in the presence of Nourseothricin. NAT is compatible with other selection markers puromycin, hygromycin, neomycin, blasticidin, and is a valuable addition to the repertoire of mammalian selection markers.

  6. Methotrexate-Loaded Four-Arm Star Amphiphilic Block Copolymer Elicits CD8+ T Cell Response against a Highly Aggressive and Metastatic Experimental Lymphoma.

    Science.gov (United States)

    Hira, Sumit Kumar; Ramesh, Kalyan; Gupta, Uttam; Mitra, Kheyanath; Misra, Nira; Ray, Biswajit; Manna, Partha Pratim

    2015-09-16

    We have synthesized a well-defined four-arm star amphiphilic block copolymer [poly(DLLA)-b-poly(NVP)]4 [star-(PDLLA-b-PNVP)4] that consists of D,L-lactide (DLLA) and N-vinylpyrrolidone (NVP) via the combination of ring-opening polymerization (ROP) and xanthate-mediated reversible addition-fragmentation chain transfer (RAFT) polymerization. Synthesis of the polymer was verified by 1H NMR spectroscopy and gel permeation chromatography (GPC). The amphiphilic four-arm star block copolymer forms spherical micelles in water as demonstrated by transmission electron microscopy (TEM) and 1H NMR spectroscopy. Pyrene acts as a probe to ascertain the critical micellar concentration (cmc) by using fluorescence spectroscopy. Methotrexate (MTX)-loaded polymeric micelles of star-(PDLLA15-b-PNVP10)4 amphiphilic block copolymer were prepared and characterized by fluorescence and TEM studies. Star-(PDLLA15-b-PNVP10)4 copolymer was found to be significantly effective with respect to inhibition of proliferation and lysis of human and murine lymphoma cells. The amphiphilic block copolymer causes cell death in parental and MTX-resistant Dalton lymphoma (DL) and Raji cells. The formulation does not cause hemolysis in red blood cells and is tolerant to lymphocytes compared to free MTX. Therapy with MTX-loaded star-(PDLLA15-b-PNVP10)4 amphiphilic block copolymer micelles prolongs the life span of animals with neoplasia by reducing the tumor load, preventing metastasis and augmenting CD8+ T cell-mediated adaptive immune responses. PMID:26323031

  7. IDENTIFICATION OF CANINE VISCERAL LEISHMANIASIS IN A PREVIOUSLY UNAFFECTED AREA BY CONVENTIONAL DIAGNOSTIC TECHNIQUES AND CELL-BLOCK FIXATION

    Directory of Open Access Journals (Sweden)

    Tuanne Rotti ABRANTES

    2016-01-01

    Full Text Available After the report of a second case of canine visceral leishmaniasis (CVL in São Bento da Lagoa, Itaipuaçu, in the municipality of Maricá, Rio de Janeiro State, an epidemiological survey was carried out, through active search, totaling 145 dogs. Indirect immunofluorescence assay (IFA, enzyme-linked immunosorbent assay (ELISA, and rapid chromatographic immunoassay based on dual-path platform (DPP(r were used to perform the serological examinations. The parasitological diagnosis of cutaneous fragments was performed by parasitological culture, histopathology, and immunohistochemistry. In the serological assessment, 21 dogs were seropositive by IFA, 17 by ELISA, and 11 by DPP(r, with sensitivity of 66.7%, 66.7% and 50%, and specificity of 87.2%, 90.2% and 94%, respectively for each technique. The immunohistochemistry of bone marrow using the cell-block technique presented the best results, with six positive dogs found, three of which tested negative by the other parasitological techniques. Leishmania sp. was isolated by parasitological culture in three dogs. The detection of autochthonous Leishmania infantum in Itaipuaçu, and the high prevalence of seropositive dogs confirm the circulation of this parasite in the study area and alert for the risk of expansion in the State of Rio de Janeiro.

  8. Reversal of morphine-induced cell-type-specific synaptic plasticity in the nucleus accumbens shell blocks reinstatement.

    Science.gov (United States)

    Hearing, Matthew C; Jedynak, Jakub; Ebner, Stephanie R; Ingebretson, Anna; Asp, Anders J; Fischer, Rachel A; Schmidt, Clare; Larson, Erin B; Thomas, Mark John

    2016-01-19

    Drug-evoked plasticity at excitatory synapses on medium spiny neurons (MSNs) of the nucleus accumbens (NAc) drives behavioral adaptations in addiction. MSNs expressing dopamine D1 (D1R-MSN) vs. D2 receptors (D2R-MSN) can exert antagonistic effects in drug-related behaviors, and display distinct alterations in glutamate signaling following repeated exposure to psychostimulants; however, little is known of cell-type-specific plasticity induced by opiates. Here, we find that repeated morphine potentiates excitatory transmission and increases GluA2-lacking AMPA receptor expression in D1R-MSNs, while reducing signaling in D2-MSNs following 10-14 d of forced abstinence. In vivo reversal of this pathophysiology with optogenetic stimulation of infralimbic cortex-accumbens shell (ILC-NAc shell) inputs or treatment with the antibiotic, ceftriaxone, blocked reinstatement of morphine-evoked conditioned place preference. These findings confirm the presence of overlapping and distinct plasticity produced by classes of abused drugs within subpopulations of MSNs that may provide targetable molecular mechanisms for future pharmacotherapies. PMID:26739562

  9. IDENTIFICATION OF CANINE VISCERAL LEISHMANIASIS IN A PREVIOUSLY UNAFFECTED AREA BY CONVENTIONAL DIAGNOSTIC TECHNIQUES AND CELL-BLOCK FIXATION

    Science.gov (United States)

    ABRANTES, Tuanne Rotti; MADEIRA, Maria de Fátima; da SILVA, Denise Amaro; PERIÉ, Carolina dos Santos F. S.; V. MENDES, Artur Augusto; MENEZES, Rodrigo Caldas; SILVA, Valmir Laurentino; FIGUEIREDO, Fabiano Borges

    2016-01-01

    After the report of a second case of canine visceral leishmaniasis (CVL) in São Bento da Lagoa, Itaipuaçu, in the municipality of Maricá, Rio de Janeiro State, an epidemiological survey was carried out, through active search, totaling 145 dogs. Indirect immunofluorescence assay (IFA), enzyme-linked immunosorbent assay (ELISA), and rapid chromatographic immunoassay based on dual-path platform (DPP(r)) were used to perform the serological examinations. The parasitological diagnosis of cutaneous fragments was performed by parasitological culture, histopathology, and immunohistochemistry. In the serological assessment, 21 dogs were seropositive by IFA, 17 by ELISA, and 11 by DPP(r), with sensitivity of 66.7%, 66.7% and 50%, and specificity of 87.2%, 90.2% and 94%, respectively for each technique. The immunohistochemistry of bone marrow using the cell-block technique presented the best results, with six positive dogs found, three of which tested negative by the other parasitological techniques. Leishmania sp. was isolated by parasitological culture in three dogs. The detection of autochthonous Leishmania infantum in Itaipuaçu, and the high prevalence of seropositive dogs confirm the circulation of this parasite in the study area and alert for the risk of expansion in the State of Rio de Janeiro. PMID:26910449

  10. Amlexanox Blocks the Interaction between S100A4 and Epidermal Growth Factor and Inhibits Cell Proliferation.

    Science.gov (United States)

    Cho, Ching Chang; Chou, Ruey-Hwang; Yu, Chin

    2016-01-01

    The human S100A4 protein binds calcium, resulting in a change in its conformation to promote the interaction with its target protein. Human epidermal growth factor (EGF) is the target protein of S100A4 and a critical ligand of the receptor EGFR. The EGF/EGFR system promotes cell survival, differentiation, and growth by activating several signaling pathways. Amlexanox is an anti-inflammatory and anti-allergic drug that is used to treat recurrent aphthous ulcers. In the present study, we determined that amlexanox interacts with S100A4 using heteronuclear single quantum correlation titration. We elucidated the interactions of S100A4 with EGF and amlexanox using fluorescence and nuclear magnetic resonance spectroscopy. We generated two binary models (for the S100A4-EGF and S100A4-amlexanox complexes) and observed that amlexanox and EGF share a similar binding region in mS100A4. We also used a WST-1 assay to investigate the bioactivity of S100A4, EGF, and amlexanox, and found that amlexanox blocks the binding between S100A4 and EGF, and is therefore useful for the development of new anti-proliferation drugs. PMID:27559743

  11. The virion host shutoff RNase plays a key role in blocking the activation of protein kinase R in cells infected with herpes simplex virus 1.

    Science.gov (United States)

    Sciortino, Maria Teresa; Parisi, Tiziana; Siracusano, Gabriel; Mastino, Antonio; Taddeo, Brunella; Roizman, Bernard

    2013-03-01

    Earlier studies have shown that active MEK blocks the activation of protein kinase R (PKR), a component of antiviral innate immune responses. In this report we show that the herpes simplex virus 1 virion host shutoff (VHS) RNase protein and MEK (mitogen-activated protein kinase kinase) act cooperatively in blocking the activation of PKR. This conclusion is based on the following. (i) In contrast to viral gene expression in the parental cell line or a cell line expressing a constitutively active MEK, the replication of a VHS mutant is particularly impaired in cells expressing dominant negative MEK. In this cell line PKR is activated by phosphorylation, and the accumulation of several viral proteins is delayed. (ii) In transfected cells, wild-type VHS blocked the activation of PKR, whereas PKR was activated in cells transfected with a mutant VHS or with plasmids encoding the VHS RNase and VP16 and VP22, the two viral proteins that neutralize the RNase activity of VHS. The results suggest that early in infection the VHS RNase degrades RNAs that activate PKR. Coupled with published data, the results suggest that inhibition of activation of PKR or its effect on viral replication is staged early in infection by VHS, postsynthesis of VP16 and VP22 by the γ(1)34.5 protein, and very late in infection by the U(S)11 protein.

  12. Curcumin and cancer cells: how many ways can curry kill tumor cells selectively?

    Science.gov (United States)

    Ravindran, Jayaraj; Prasad, Sahdeo; Aggarwal, Bharat B

    2009-09-01

    Cancer is a hyperproliferative disorder that is usually treated by chemotherapeutic agents that are toxic not only to tumor cells but also to normal cells, so these agents produce major side effects. In addition, these agents are highly expensive and thus not affordable for most. Moreover, such agents cannot be used for cancer prevention. Traditional medicines are generally free of the deleterious side effects and usually inexpensive. Curcumin, a component of turmeric (Curcuma longa), is one such agent that is safe, affordable, and efficacious. How curcumin kills tumor cells is the focus of this review. We show that curcumin modulates growth of tumor cells through regulation of multiple cell signaling pathways including cell proliferation pathway (cyclin D1, c-myc), cell survival pathway (Bcl-2, Bcl-xL, cFLIP, XIAP, c-IAP1), caspase activation pathway (caspase-8, 3, 9), tumor suppressor pathway (p53, p21) death receptor pathway (DR4, DR5), mitochondrial pathways, and protein kinase pathway (JNK, Akt, and AMPK). How curcumin selectively kills tumor cells, and not normal cells, is also described in detail. PMID:19590964

  13. Mutation of the dengue virus type 2 envelope protein heparan sulfate binding sites or the domain III lateral ridge blocks replication in Vero cells prior to membrane fusion

    International Nuclear Information System (INIS)

    Using an infectious cDNA clone we engineered seven mutations in the putative heparan sulfate- and receptor-binding motifs of the envelope protein of dengue virus serotype 2, strain 16681. Four mutant viruses, KK122/123EE, E202K, G304K, and KKK305/307/310EEE, were recovered following transfection of C6/36 cells. A fifth mutant, KK291/295EE, was recovered from C6/36 cells with a compensatory E295V mutation. All mutants grew in and mediated fusion of virus-infected C6/36 cells, but three of the mutants, KK122/123EE, E202K, G304K, did not grow in Vero cells without further modification. Two Vero cell lethal mutants, KK291/295EV and KKK307/307/310EEE, failed to replicate in DC-SIGN-transformed Raji cells and did not react with monoclonal antibodies known to block DENV attachment to Vero cells. Additionally, both mutants were unable to initiate negative-strand vRNA synthesis in Vero cells by 72 h post-infection, suggesting that the replication block occurred prior to virus-mediated membrane fusion. - Highlights: • Heparan sulfate- and receptor-binding motifs of DENV2 envelope protein were mutated. • Four mutant viruses were isolated—all could fuse C6/36 cells. • Two of these mutants were lethal in Vero cells without further modification. • Lethal mutations were KK291/295EV and KKK305/307/310EEE. • Cell attachment was implicated as the replication block for both mutants

  14. Mutation of the dengue virus type 2 envelope protein heparan sulfate binding sites or the domain III lateral ridge blocks replication in Vero cells prior to membrane fusion

    Energy Technology Data Exchange (ETDEWEB)

    Roehrig, John T., E-mail: jtr1@cdc.gov [Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, CO 80521 (United States); Butrapet, Siritorn; Liss, Nathan M. [Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, CO 80521 (United States); Bennett, Susan L. [Arthropod-borne and Infectious Diseases Laboratory, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO 80523 (United States); Luy, Betty E.; Childers, Thomas; Boroughs, Karen L.; Stovall, Janae L.; Calvert, Amanda E. [Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, CO 80521 (United States); Blair, Carol D. [Arthropod-borne and Infectious Diseases Laboratory, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO 80523 (United States); Huang, Claire Y.-H. [Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, CO 80521 (United States)

    2013-07-05

    Using an infectious cDNA clone we engineered seven mutations in the putative heparan sulfate- and receptor-binding motifs of the envelope protein of dengue virus serotype 2, strain 16681. Four mutant viruses, KK122/123EE, E202K, G304K, and KKK305/307/310EEE, were recovered following transfection of C6/36 cells. A fifth mutant, KK291/295EE, was recovered from C6/36 cells with a compensatory E295V mutation. All mutants grew in and mediated fusion of virus-infected C6/36 cells, but three of the mutants, KK122/123EE, E202K, G304K, did not grow in Vero cells without further modification. Two Vero cell lethal mutants, KK291/295EV and KKK307/307/310EEE, failed to replicate in DC-SIGN-transformed Raji cells and did not react with monoclonal antibodies known to block DENV attachment to Vero cells. Additionally, both mutants were unable to initiate negative-strand vRNA synthesis in Vero cells by 72 h post-infection, suggesting that the replication block occurred prior to virus-mediated membrane fusion. - Highlights: • Heparan sulfate- and receptor-binding motifs of DENV2 envelope protein were mutated. • Four mutant viruses were isolated—all could fuse C6/36 cells. • Two of these mutants were lethal in Vero cells without further modification. • Lethal mutations were KK291/295EV and KKK305/307/310EEE. • Cell attachment was implicated as the replication block for both mutants.

  15. Achieving high performance non-fullerene organic solar cells through tuning the numbers of electron deficient building blocks of molecular acceptors

    Science.gov (United States)

    Yang, Lei; Chen, Yusheng; Chen, Shangshang; Dong, Tao; Deng, Wei; Lv, Lei; Yang, Saina; Yan, He; Huang, Hui

    2016-08-01

    Two analogous dimer and tetramer compounds, SF-PDI2 and SF-PDI4, were designed, theoretically calculated, synthesized, and developed as electron acceptors for organic solar cells. The effects of the number of the electron deficient building blocks on the optical absorption, energy levels, charge transport, morphology, crystallinity, and photovoltaic performance of the molecules were investigated. In combination with two different donors, PTB7-Th and PffBT4T-2OD, the results showed that increasing the numbers of PDI building blocks is beneficial to photovoltaic performance and leads to efficiency over 5%.

  16. Adhesion of ZAP-70+ chronic lymphocytic leukemia cells to stromal cells is enhanced by cytokines and blocked by inhibitors of the PI3-kinase pathway.

    Science.gov (United States)

    Lafarge, Sandrine T; Johnston, James B; Gibson, Spencer B; Marshall, Aaron J

    2014-01-01

    CLL cell survival and proliferation is enhanced through direct contact with supporting cells present in lymphoid tissues. PI3Ks are critical signal transduction enzymes controlling B cell survival and activation. PI3K inhibitors have entered clinical trials and show promising therapeutic activity; however, it is unclear whether PI3K inhibitor drugs differentially affect ZAP-70 positive versus negative CLL cells or target specific microenvironmental interactions. Here we provide evidence that CD40L+IL-4, IL-8 or IL-6 enhance adhesion to stromal cells, with IL-6 showing a selective effect on ZAP-70 positive cells. Stimulatory effects of IL-8 or IL-6 are fully reversed by PI3K inhibition, while the effects of CD40L+IL-4 are partially reversed. While CD40L+IL-4 is the only stimulation increasing CLL cell survival for all patient groups, IL-6 protects ZAP-70 positive cells from cell death induced by PI3K inhibition. Altogether, our results indicate that targeting the PI3K pathway can reverse protective CLL-microenvironment interactions in both ZAP-70 positive and negative CLL despite their differences in cytokine responsiveness.

  17. Replicator Dynamics of of Cancer Stem Cell; Selection in the Presence of Differentiation and Plasticity

    OpenAIRE

    Kaveh, Kamran; Kohandel, Mohammad; Sivaloganathan, Siv

    2014-01-01

    Stem cells have the potential to produce lineages of non-stem cell populations (differentiated cells) via a ubiquitous hierarchal division scheme. Differentiation of a stem cell into (partially) differentiated cells can happen either symmetrically or asymmetrically. The selection dynamics of a mutant cancer stem cell should be investigated in the light of a stem cell proliferation hierarchy and presence of a non-stem cell population. By constructing a three-compartment Moran-type model compos...

  18. Planning Block Play Experiences for Young Children.

    Science.gov (United States)

    Baker, Betty Ruth

    Playing with blocks can facilitate the creative, social, emotional, physical, and cognitive development of young children. This article presents information and activities concerning block play and its role in young children's experience. Topics covered include: (1) types of blocks; (2) selection of blocks and accessories; (3) planning of the…

  19. A potent oral P-selectin blocking agent improves microcirculatory blood flow and a marker of endothelial cell injury in patients with sickle cell disease.

    Science.gov (United States)

    Kutlar, Abdullah; Ataga, Kenneth I; McMahon, Lillian; Howard, Joanna; Galacteros, Frederic; Hagar, Ward; Vichinsky, Elliott; Cheung, Anthony T W; Matsui, Neil; Embury, Stephen H

    2012-05-01

    Abnormal blood flow accounts for most of the clinical morbidity of sickle cell disease (SCD) [1,2]. Most notably, occlusion of flow in the microvasculature causes the acute pain crises [3] that are the commonest cause for patients with SCD to seek medical attention [4] and major determinants of their quality of life [5]. Based on evidence that endothelial P-selectin is central to the abnormal blood flow in SCD we provide results from four of our studies that are germane to microvascular blood flow in SCD. A proof-of-principle study established that doses of heparin lower than what are used for anticoagulation but sufficient to block P-selectin improved microvascular blood flow inpatients with SCD. An in vitro study showed that Pentosan Polysulfate Sodium (PPS) had greater P-selectin blocking activity than heparin. A Phase I clinical study demonstrated that a single oral dose of PPS increased microvascular blood flow in patients with SCD. A Phase II clinical study that was not completed documented that daily oral doses of PPS administered for 8 weeks lowered plasma levels of sVCAM-1 and tended to improve microvascular blood flow in patients with SCD. These data support the concept that P-selectin on the microvascular endothelium is critical to both acute vascular occlusion and chronically impaired microvascular blood flow in SCD. They also demonstrate that oral PPS is beneficial to microvascular sickle cell blood flow and has potential as an efficacious agent for long-term prophylactic therapy of SCD.

  20. Fabrication of honeycomb-structured poly(ethylene glycol)-block-poly(lactic acid) porous films and biomedical applications for cell growth

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Honeycomb-structured PEG-PLA porous films were fabricated. • The organization of pores depends on molecular weight ratio of PEG-to-PLA block. • The pores in the film were internally decorated with a layer of PEG. • The honeycomb-structured PEG-PLA film was suitable as a substrate for cell growth. - Abstract: A series of poly(ethylene glycol)-block-poly(lactic acid) (PEG-PLA) copolymers with a hydrophobic PLA block of different molecular weights and a fixed length hydrophilic PEG were synthesized successfully and characterized. These amphiphilic block copolymers were used to fabricate honeycomb-structured porous films using the breath figure (BF) templating technique. The surface topology and composition of the highly ordered pattern film were further characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and fluorescence microscopy. The results indicated that the PEG-to-PLA block molecular weight ratio influenced the BF film surface topology. The film with the best ordered pores was obtained with a PEG-to-PLA ratio of 2.0 × 103:3.0 × 104. The self-organization of the hydrophilic PEG chains within the pores was confirmed by XPS and fluorescence labeled PEG. A model is proposed to elucidate the stabilization process of the amphiphilic PEG-PLA aggregated architecture on the water droplet-based templates. In addition, GFP-U87 cell viability has been investigated by MTS test and the cell morphology on the honeycomb-structured PEG-PLA porous film has been evaluated using phase-contrast microscope. This porous film is shown to be suitable as a matrix for cell growth

  1. Fabrication of honeycomb-structured poly(ethylene glycol)-block-poly(lactic acid) porous films and biomedical applications for cell growth

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Bingjian [Key Laboratory of Special Functional Aggregated Materials, Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250199 (China); College of chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Shandong Normal University, Jinan 250014 (China); Zhu, Qingzeng, E-mail: qzzhu@sdu.edu.cn [Key Laboratory of Special Functional Aggregated Materials, Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250199 (China); Yao, Linli [Key Laboratory of the Ministry of Education for Experimental Teratology, Department of Histology and Embryology, Shandong University School of Medicine, 250012 Jinan (China); Hao, Jingcheng [Key Laboratory of Special Functional Aggregated Materials, Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250199 (China)

    2015-03-30

    Graphical abstract: - Highlights: • Honeycomb-structured PEG-PLA porous films were fabricated. • The organization of pores depends on molecular weight ratio of PEG-to-PLA block. • The pores in the film were internally decorated with a layer of PEG. • The honeycomb-structured PEG-PLA film was suitable as a substrate for cell growth. - Abstract: A series of poly(ethylene glycol)-block-poly(lactic acid) (PEG-PLA) copolymers with a hydrophobic PLA block of different molecular weights and a fixed length hydrophilic PEG were synthesized successfully and characterized. These amphiphilic block copolymers were used to fabricate honeycomb-structured porous films using the breath figure (BF) templating technique. The surface topology and composition of the highly ordered pattern film were further characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and fluorescence microscopy. The results indicated that the PEG-to-PLA block molecular weight ratio influenced the BF film surface topology. The film with the best ordered pores was obtained with a PEG-to-PLA ratio of 2.0 × 10{sup 3}:3.0 × 10{sup 4}. The self-organization of the hydrophilic PEG chains within the pores was confirmed by XPS and fluorescence labeled PEG. A model is proposed to elucidate the stabilization process of the amphiphilic PEG-PLA aggregated architecture on the water droplet-based templates. In addition, GFP-U87 cell viability has been investigated by MTS test and the cell morphology on the honeycomb-structured PEG-PLA porous film has been evaluated using phase-contrast microscope. This porous film is shown to be suitable as a matrix for cell growth.

  2. Ghost Block

    OpenAIRE

    Webb, Neil

    2011-01-01

    Filmed on the English south coast 'Ghost Block' depicts the uncanny and eerie atmosphere at the site of a WW2 coastal defence line. The concrete cubes were used as an anti-invasion blockade against potential landing forces. This protection line now slowly decaying and becoming enmeshed into the environment still acts as a defence to repel unwanted visitors. The area is a natural reserve to nesting birds that often lay eggs directly onto the beach surface. The blocks act as a final barrier ...

  3. Visual cells remember earlier applied target: plasticity of orientation selectivity.

    Directory of Open Access Journals (Sweden)

    Narcis Ghisovan

    Full Text Available BACKGROUND: A canonical proposition states that, in mature brain, neurons responsive to sensory stimuli are tuned to specific properties installed shortly after birth. It is amply demonstrated that that neurons in adult visual cortex of cats are orientation-selective that is they respond with the highest firing rates to preferred oriented stimuli. METHODOLOGY/PRINCIPAL FINDINGS: In anesthetized cats, prepared in a conventional fashion for single cell recordings, the present investigation shows that presenting a stimulus uninterruptedly at a non-preferred orientation for twelve minutes induces changes in orientation preference. Across all conditions orientation tuning curves were investigated using a trial by trial method. Contrary to what has been previously reported with shorter adaptation duration, twelve minutes of adaptation induces mostly attractive shifts, i.e. toward the adapter. After a recovery period allowing neurons to restore their original orientation tuning curves, we carried out a second adaptation which produced three major results: (1 more frequent attractive shifts, (2 an increase of their magnitude, and (3 an additional enhancement of responses at the new or acquired preferred orientation. Additionally, we also show that the direction of shifts depends on the duration of the adaptation: shorter adaptation in most cases produces repulsive shifts, whereas adaptation exceeding nine minutes results in attractive shifts, in the same unit. Consequently, shifts in preferred orientation depend on the duration of adaptation. CONCLUSION/SIGNIFICANCE: The supplementary response improvements indicate that neurons in area 17 keep a memory trace of the previous stimulus properties, thereby upgrading cellular performance. It also highlights the dynamic nature of basic neuronal properties in adult cortex since repeated adaptations modified both the orientation tuning selectivity and the response strength to the preferred orientation. These

  4. A COMPARATIVE STUDY OF CHAIN DYNAMICS OF DI-AND TRI-BLOCK COPOLYMERS IN SEMIDILUTE SOLUTION IN A NON-SELECTIVE SOLVENT

    Institute of Scientific and Technical Information of China (English)

    Wei Li; Liang-zhi Hong; To Ngai; Hai-ying Huang; Tian-bai He; Chi Wu

    2004-01-01

    The chain dynamics of a pair of diblock poly(styrene-b-butadiene) (PS210-b-PB960) and triblock poly(styrene-b-butadiene-b-styrene) (PS200-b-PB1815-b-PS200) copolymers in both dilute and semidilute toluene solutions has been comparatively studied by dynamic laser light scattering. As expected, the mutual diffusion of individual chain changes into a fast cooperative diffusion of the chain segments ("blobs") between two neighboring entanglement points for both the copolymers as the solution changes from dilute to semidilute. Further increases of the concentration lead to a second slow relaxation mode. For the triblock chains, there exists an additional middle relaxation between the fast and the slow modes.with 0.33 <α< 0.44, much smaller than 0.75 predicted or 0.72 observed for linear homopolymer chains in good solvent. It implies that the solvent quality of toluene for PB might not be as good as that for PS. Due to such a difference in solubility, it is reasonable to speculate that the PB and PS blocks are transiently segregated in semidilute solution. The relaxation of these transient PB and PS richer domains leads to the observed slow relaxation. Such a speculation is supported by the appearance of an additional slow relaxation mode in the study of polyisoprene-b-polystyrene-b-polyisoprene in semidilute solution in cyclohexane, a non-selective solvent, in which we alternated the solubility difference by a variation of the solution temperature.

  5. Laser-guided cervical selective nerve root block with the Dyna-CT: initial experience of three-dimensional puncture planning with an ex-vivo model.

    Directory of Open Access Journals (Sweden)

    Miriam I E Freundt

    Full Text Available BACKGROUND: Cervical selective nerve root block (CSNRB is a well-established, minimally invasive procedure to treat radicular cervical pain. However, the procedure is technically challenging and might lead to major complications. The objective of this study was to evaluate the feasibility of a three-dimensional puncture planning and two-dimensional laser-guidance system for CSNRB in an ex-vivo model. METHODS: Dyna-CT of the cervical spine of an ex-vivo lamb model was performed with the Artis Zee® Ceiling (Siemens Medical Solutions, Erlangen, Germany to acquire multiplanar reconstruction images. 15 cervical nerve root punctures were planned and conducted with the syngo iGuide® laser-guidance system. Needle tip location and contrast dye distribution were analyzed by two independent investigators. Procedural, planning, and fluoroscopic time, tract length, and dose area product (DAP were acquired for each puncture. RESULTS: All 15 punctures were rated as successful with 12 punctures on the first attempt. Total procedural time was approximately 5 minutes. Mean planning time for the puncture was 2.03 (±0.39 min. Mean puncture time was 2.16 (±0.32 min, while mean fluoroscopy time was 0.17 (±0.06 min. Mean tract length was 2.68 (±0.23 cm. Mean total DAP was 397.45 (±15.63 µGy m(2. CONCLUSION: CSNRB performed with Dyna-CT and the tested laser guidance system is feasible. 3D pre-puncture planning is easy and fast and the laser-guiding system ensures very accurate and intuitive puncture control.

  6. Coupling Binding to Catalysis – Using Yeast Cell Surface Display to Select Enzymatic Activities

    OpenAIRE

    Zhang, Keya; Bhuripanyo, Karan; Wang, Yiyang; Yin, Jun

    2015-01-01

    We find yeast cell surface display can be used to engineer enzymes by selecting the enzyme library for high affinity binding to reaction intermediates. Here we cover key steps of enzyme engineering on the yeast cell surface including library design, construction, and selection based on magnetic and fluorescence activated cell sorting.

  7. Coupling Binding to Catalysis: Using Yeast Cell Surface Display to Select Enzymatic Activities.

    Science.gov (United States)

    Zhang, Keya; Bhuripanyo, Karan; Wang, Yiyang; Yin, Jun

    2015-01-01

    We find yeast cell surface display can be used to engineer enzymes by selecting the enzyme library for high affinity binding to reaction intermediates. Here we cover key steps of enzyme engineering on the yeast cell surface including library design, construction, and selection based on magnetic and fluorescence-activated cell sorting. PMID:26060080

  8. Epidural block

    Science.gov (United States)

    ... Drugs & Supplements Videos & Tools Español You Are Here: Home ... It numbs or causes a loss of feeling in the lower half your body. This lessens the pain of contractions during childbirth. An epidural block may also be used to ...

  9. A highly calcium-selective cation current activated by intracellular calcium release in MDCK cells.

    Science.gov (United States)

    Delles, C; Haller, T; Dietl, P

    1995-08-01

    1. The whole-cell patch clamp technique and fluorescence microscopy with the Ca2+ indicators fura-2 and fluo-3 were used to measure the whole-cell current and the free intracellular Ca2+ concentration ([Ca2+]i) in Madin-Darby canine kidney (MDCK) cells. 2. In a Ca(2+)-free bath solution, thapsigargin (TG) caused a transient increase of [Ca2+]i. Subsequent addition of Ca2+ caused a long lasting elevation of [Ca2+]i. 3. In a Ca(2+)-free bath solution, extracellular application of TG, ATP or ionomycin, or intracellular application of inositol 1,4,5-trisphosphate (IP3), caused a small but significant inward current (Iin) and a transient outward Ca(2+)-dependent K+ current (IK(Ca)), consistent with intracellular Ca2+ release. Subsequent addition of Ca2+ induced a prominent Iin with a current density of -4.2 +/- 0.7 pA pF-1. This Iin was unaffected by inositol 1,3,4,5-tetrakisphosphate (IP4). 4. Na+ replacement by mannitol, N-methyl-D-glucamine+ (NMG+), aminomethylidin-trimethanol+ (Tris+) or choline+ reduced Iin by 54, 65, 52 and 56%, respectively. This indicates an apparent Ca2+ selectivity over Na+ of 26:1. Iin was, however, unaffected by replacing Cl- with gluconate- or by the K+ channel blocker charybdotoxin (CTX). 5. Iin was completely blocked by La3+ (IC50 = 0.77 microM). Consistently, La3+ completely reversed the TG-induced elevation of [Ca2+]i. SK&F 96365 (1-[3-(4-methoxyphenyl)-propoxyl]-1-(4-methoxy-phenyl)-ethyl-1H-im idazole) HCl did not inhibit the TG-induced Iin. It did, however, exhibit a biphasic effect on [Ca2+]i, consisting of an initial Ca2+ decay and a subsequent Ca2+ elevation. La3+ completely reversed the SK&F 96365-induced elevation of [Ca2+]i. 6. In the absence of Na+, Iin was dependent on the bath Ca2+ concentration (EC50 = 1.02 mM). Ca2+ replacement by Ba2+ or Mn2+ resulted in a reduction of Iin by 95 and 94%, respectively. 7. From these experiments we conclude that Ca2+ release from intracellular Ca2+ stores, induced by different independent

  10. Amphiphilic block-graft copolymer templates for organized mesoporous TiO2 films in dye-sensitized solar cells

    Science.gov (United States)

    Lim, Jung Yup; Lee, Chang Soo; Lee, Jung Min; Ahn, Joonmo; Cho, Hyung Hee; Kim, Jong Hak

    2016-01-01

    Amphiphilic block-graft copolymers composed of poly(styrene-b-butadiene-b-styrene) (SBS) backbone and poly(oxyethylene methacrylate) (POEM) side chains are synthesized and combined with hydrophilically preformed TiO2 (Pre-TiO2), which works as a structural binder as well as titania source. This results in the formation of crack free, 6-μm-thick, organized mesoporous TiO2 (OM-TiO2) films via one-step doctor-blading based on self-assembly of SBS-g-POEM as well as preferential interaction of POEM chains with Pre-TiO2. SBS-g-POEM with different numbers of ethylene oxide repeating units, SBS-g-POEM(500) and SBS-g-POEM(950), are used to form OM-TiO2(500) and OM-TiO2(950), respectively. The efficiencies of dye-sensitized solar cells (DSSCs) with a quasi-solid-state polymer electrolyte reach 5.7% and 5.8% at 100 mW/cm2 for OM-TiO2(500) and OM-TiO2(950), respectively. The surface area of OM-TiO2(950) was greater than that of OM-TiO2(500) but the light reflectance was lower in the former, which is responsible for similar efficiency. Both DSSCs exhibit much higher efficiency than one (4.8%) with randomly-organized particulate TiO2 (Ran-TiO2), which is attributed to the higher dye loading, reduced charge recombination and improved pore infiltration of OM-TiO2. When utilizing poly((1-(4-ethenylphenyl)methyl)-3-butyl-imidazolium iodide) (PEBII) and mesoporous TiO2 spheres as the solid electrolyte and the scattering layer, the efficiency increases up to 7.5%, one of the highest values for N719-based solid-state DSSCs.

  11. Preconditioning with associated blocking of Ca2+ inflow alleviates hypoxia-induced damage to pancreatic β-cells.

    Directory of Open Access Journals (Sweden)

    Zuheng Ma

    Full Text Available OBJECTIVE: Beta cells of pancreatic islets are susceptible to functional deficits and damage by hypoxia. Here we aimed to characterize such effects and to test for and pharmacological means to alleviate a negative impact of hypoxia. METHODS AND DESIGN: Rat and human pancreatic islets were subjected to 5.5 h of hypoxia after which functional and viability parameters were measured subsequent to the hypoxic period and/or following a 22 h re-oxygenation period. Preconditioning with diazoxide or other agents was usually done during a 22 h period prior to hypoxia. RESULTS: Insulin contents decreased by 23% after 5.5 h of hypoxia and by 61% after a re-oxygenation period. Preconditioning with diazoxide time-dependently alleviated these hypoxia effects in rat and human islets. Hypoxia reduced proinsulin biosynthesis ((3H-leucine incorporation into proinsulin by 35%. Preconditioning counteracted this decrease by 91%. Preconditioning reduced hypoxia-induced necrosis by 40%, attenuated lowering of proteins of mitochondrial complexes I-IV and enhanced stimulation of HIF-1-alpha and phosphorylated AMPK proteins. Preconditioning by diazoxide was abolished by co-exposure to tolbutamide or elevated potassium (i.e. conditions which increase Ca(2+ inflow. Preconditioning with nifedipine, a calcium channel blocker, partly reproduced effects of diazoxide. Both diazoxide and nifedipine moderately reduced basal glucose oxidation whereas glucose-induced oxygen consumption (tested with diazoxide was unaffected. Preconditioning with diaxoxide enhanced insulin contents in transplants of rat islets to non-diabetic rats and lowered hyperglycemia vs. non-preconditioned islets in streptozotocin-diabetic rats. Preconditioning of human islet transplants lowered hyperglycemia in streptozotocin-diabetic nude mice. CONCLUSIONS: 1 Prior blocking of Ca(2+ inflow associates with lesser hypoxia-induced damage, 2 preconditioning affects basal mitochondrial metabolism and accelerates

  12. Novel Cell Selection Proceduref LTE Hetnets Based on Mathematical Modelling of Proportional Fair Scheduling

    Directory of Open Access Journals (Sweden)

    Mohamed A. AboulHassan

    2013-12-01

    Full Text Available Femtocells have been considered one of the most imp ortant technologies in LTE networks to solve indoor coverage problem, however the randomness deployment of femtocells, leads to great challenge for select ing optimum serving cell. In this work, a new cell sele ction algorithm is proposed that enables new user t o select best serving cell whereas several factors ar e put into consideration other than highest instant aneous SNR or maximum RSRP such as cell load .A new predic tion algorithm is designed to predict the performance of (PF scheduling algorithm to calcula te expected number of RBs to be scheduled to new user, then reduction in achievable data rate due to both received SNR and instant cell load is estimat ed. The numerical results show that the new proposed ce ll selection algorithm achieves higher average cell throughput than conventional cell selection methods and achieves less cell load variance between diffe rent adjacent cells.

  13. Performance enhancement of perovskite solar cells with Mg-doped TiO2 compact film as the hole-blocking layer

    International Nuclear Information System (INIS)

    In this letter, we report perovskite solar cells with thin dense Mg-doped TiO2 as hole-blocking layers (HBLs), which outperform cells using TiO2 HBLs in several ways: higher open-circuit voltage (Voc) (1.08 V), power conversion efficiency (12.28%), short-circuit current, and fill factor. These properties improvements are attributed to the better properties of Mg-modulated TiO2 as compared to TiO2 such as better optical transmission properties, upshifted conduction band minimum (CBM) and downshifted valence band maximum (VBM), better hole-blocking effect, and higher electron life time. The higher-lying CBM due to the modulation with wider band gap MgO and the formation of magnesium oxide and magnesium hydroxides together resulted in an increment of Voc. In addition, the Mg-modulated TiO2 with lower VBM played a better role in the hole-blocking. The HBL with modulated band position provided better electron transport and hole blocking effects within the device

  14. Bypassing antibiotic selection: positive screening of genetically modified cells with an antigen-dependent proliferation switch

    OpenAIRE

    Kawahara, Masahiro; Ueda, Hiroshi; Morita, Sumiyo; Tsumoto, Kouhei; Kumagai, Izumi; Nagamune, Teruyuki

    2003-01-01

    While antibiotic selection has been routinely used for the selection of genetically modified cells, administration of cytotoxic drugs often leads to deleterious effects not only to inert cells but also to transfected or transduced ones. In this study, we propose an Antigen-MEdiated Genetically modified cell Amplification (AMEGA) system employing antibody/receptor chimeras without antibiotic selection. Based on a rational design where the extracellular domains of dimeric erythropoietin recepto...

  15. Clinical significance of proliferation, apoptosis and senescence of nasopharyngeal cells by the simultaneously blocking EGF, IGF-1 receptors and Bcl-xl genes

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Guodong [Anatomy and Embryology, Wuhan University School of Medicine, Wuhan, Hubei 430071 (China); Peng, Tao; Zhou, Xuhong [Department of Otolaryngology-Head and Neck Surgery, Zhongnan Hospital of Wuhan University, Wuhan 430071 (China); Zhu, Jun; Kong, Zhihua; Ma, Li; Xiong, Zhi [Anatomy and Embryology, Wuhan University School of Medicine, Wuhan, Hubei 430071 (China); Yuan, Yulin, E-mail: yuanyulin19620120@126.com [Anatomy and Embryology, Wuhan University School of Medicine, Wuhan, Hubei 430071 (China)

    2013-11-01

    Highlight: •Construction of shRNA segments expression vectors is valid by the investigation of RT-PCR for IGF1R, EGFR and Bcl-xl mRNA and protein expression. •Studies have suggested that the vectors in blocking these genes of the growth factor receptors and anti- apoptosis is capable of breaking the balance of tumor growth so that tumor trend apoptosis and senescence. •Simultaneously blocking multiple genes that are abnormally expressed may be more effective in treating cancer cells than silencing a single gene. -- Abstract: Background: In previous work, we constructed short hairpin RNA (shRNA) expression plasmids that targeted human EGF and IGF-1 receptors messenger RNA, respectively, and demonstrated that these vectors could induce apoptosis of human nasopharyngeal cell lines (CNE2) and inhibit ligand-induced pAkt and pErk activation. Method: We have constructed multiple shRNA expression vectors of targeting EGFR, IGF1R and Bcl-xl, which were transfected to the CNE2 cells. The mRNA expression was assessed by RT-PCR. The growth of the cells, cell cycle progression, apoptosis of the cells, senescent tumor cells and the proteins of EGFR, IGF1R and Bcl-xl were analyzed by MTT, flow cytometry, cytochemical therapy or Western blot. Results: In group of simultaneously blocking EGFR, IGF1R and Bcl-xl genes, the mRNA of EGFR, IGF1R and Bcl-xl expression was decreased by (66.66 ± 3.42)%, (73.97 ± 2.83)% and (64.79 ± 2.83)%, and the protein expressions was diminished to (67.69 ± 4.02)%, (74.32 ± 2.30)%, and (60.00 ± 3.34)%, respectively. Meanwhile, the cell apoptosis increased by 65.32 ± 0.18%, 65.16 ± 0.25% and 55.47 ± 0.45%, and senescent cells increased by 1.42 ± 0.15%, 2.26 ± 0.15% and 3.22 ± 0.15% in the second, third and fourth day cultures, respectively. Conclusions: Simultaneously blocking EGFR, IGF1R and Bcl-xl genes is capable of altering the balance between proliferating versus apoptotic and senescent cells in the favor of both of apoptosis and

  16. Exosomes in human semen restrict HIV-1 transmission by vaginal cells and block intravaginal replication of LP-BM5 murine AIDS virus complex.

    Science.gov (United States)

    Madison, Marisa N; Jones, Philip H; Okeoma, Chioma M

    2015-08-01

    Exosomes are membranous extracellular nanovesicles secreted by diverse cell types. Exosomes from healthy human semen have been shown to inhibit HIV-1 replication and to impair progeny virus infectivity. In this study, we examined the ability of healthy human semen exosomes to restrict HIV-1 and LP-BM5 murine AIDS virus transmission in three different model systems. We show that vaginal cells internalize exosomes with concomitant transfer of functional mRNA. Semen exosomes blocked the spread of HIV-1 from vaginal epithelial cells to target cells in our cell-to-cell infection model and suppressed transmission of HIV-1 across the vaginal epithelial barrier in our trans-well model. Our in vivo model shows that human semen exosomes restrict intravaginal transmission and propagation of murine AIDS virus. Our study highlights an antiretroviral role for semen exosomes that may be harnessed for the development of novel therapeutic strategies to combat HIV-1 transmission.

  17. Selective destruction of mouse islet beta cells by human T lymphocytes in a newly-established humanized type 1 diabetic model

    International Nuclear Information System (INIS)

    Research highlights: → Establish a human immune-mediated type 1 diabetic model in NOD-scid IL2rγnull mice. → Using the irradiated diabetic NOD mouse spleen mononuclear cells as trigger. → The islet β cells were selectively destroyed by infiltrated human T cells. → The model can facilitate translational research to find a cure for type 1 diabetes. -- Abstract: Type 1 diabetes (T1D) is caused by a T cell-mediated autoimmune response that leads to the loss of insulin-producing β cells. The optimal preclinical testing of promising therapies would be aided by a humanized immune-mediated T1D model. We develop this model in NOD-scid IL2rγnull mice. The selective destruction of pancreatic islet β cells was mediated by human T lymphocytes after an initial trigger was supplied by the injection of irradiated spleen mononuclear cells (SMC) from diabetic nonobese diabetic (NOD) mice. This resulted in severe insulitis, a marked loss of total β-cell mass, and other related phenotypes of T1D. The migration of human T cells to pancreatic islets was controlled by the β cell-produced highly conserved chemokine stromal cell-derived factor 1 (SDF-1) and its receptor C-X-C chemokine receptor (CXCR) 4, as demonstrated by in vivo blocking experiments using antibody to CXCR4. The specificity of humanized T cell-mediated immune responses against islet β cells was generated by the local inflammatory microenvironment in pancreatic islets including human CD4+ T cell infiltration and clonal expansion, and the mouse islet β-cell-derived CD1d-mediated human iNKT activation. The selective destruction of mouse islet β cells by a human T cell-mediated immune response in this humanized T1D model can mimic those observed in T1D patients. This model can provide a valuable tool for translational research into T1D.

  18. Resveratrol inhibits enterovirus 71 replication and pro-inflammatory cytokine secretion in rhabdosarcoma cells through blocking IKKs/NF-κB signaling pathway.

    Directory of Open Access Journals (Sweden)

    Li Zhang

    Full Text Available Polydatin and resveratrol, as major active components in Polygonum cuspidatum, have anti-inflammatory, antioxidant and antitumor functions. However, the effect and mechanism of polydatin and resveratrol on enterovirus 71 (EV71 have not been reported. In this study, resveratrol revealed strong antiviral activity on EV71, while polydatin had weak effect. Neither polydatin nor resveratrol exhibited influence on viral attachment. Resveratrol could effectively inhibit the synthesis of EV71/VP1 and the phosphorylation of IKKα, IKKβ, IKKγ, IKBα, NF-κB p50 and NF-κB p65, respectively. Meanwhile, the remarkably increased secretion of IL-6 and TNF-α in EV71-infected rhabdosarcoma (RD cells could be blocked by resveratrol. These results demonstrated that resveratrol inhibited EV71 replication and cytokine secretion in EV71-infected RD cells through blocking IKKs/NF-κB signaling pathway. Thus, resveratrol may have potent antiviral effect on EV71 infection.

  19. Huhe Block

    Institute of Scientific and Technical Information of China (English)

    1996-01-01

    @@ Huhe Block is located in the mid-west part of Inner Mogolia Autonomous Region, covering an area of 15 079km2, in the range of 109°40'-112°00'E and 39°23()-40°40'N. Topographically. the Fengzhen hill is to the east, the Yinshan Mounts is to the north, the Hetao Plain and Ordos Plateau are respectively in its west and south.The Yellow River flows across this block. The elevation is 1 000 m in the flat area and in the range of 1 000-1 300m. in the plateau area, good for the development of agriculture and industry as well as husbandry. It belongs to inland plateau climate with annually averaged temperature of 8℃, the minimum being -12℃ in winter and the maximum 22℃ in summer.

  20. Selective killing of cancer cells by nanoparticle-assisted ultrasound

    OpenAIRE

    Kosheleva, Olga K.; Lai, Tsung-Ching; Chen, Nelson G.; Hsiao, Michael; Chen, Chung-Hsuan

    2016-01-01

    Background Intense ultrasound, such as that used for tumor ablation, does not differentiate between cancerous and normal cells. A method combining ultrasound and biocompatible gold or magnetic nanoparticles (NPs) was developed under in vitro conditions using human breast and lung epithelial cells, which causes ultrasound to preferentially destroy cancerous cells. Results Co-cultures of BEAS-2B normal lung cells and A549 cancerous lung cells labeled with green and red fluorescent proteins, res...

  1. Early Activation of Caspases during T Lymphocyte Stimulation Results in Selective Substrate Cleavage in Nonapoptotic Cells

    OpenAIRE

    Alam, Antoine; Cohen, Luchino Y.; Aouad, Salah; Sékaly, Rafick-Pierre

    1999-01-01

    Apoptosis induced by T cell receptor (TCR) triggering in T lymphocytes involves activation of cysteine proteases of the caspase family through their proteolytic processing. Caspase-3 cleavage was also reported during T cell stimulation in the absence of apoptosis, although the physiological relevance of this response remains unclear. We show here that the caspase inhibitor benzyloxycarbonyl (Cbz)-Val-Ala-Asp(OMe)-fluoromethylketone (zVAD) blocks proliferation, major histocompatibility complex...

  2. Mechanosensory calcium-selective cation channels in epidermal cells

    Science.gov (United States)

    Ding, J. P.; Pickard, B. G.

    1993-01-01

    This paper explores the properties and likely functions of an epidermal Ca(2+)-selective cation channel complex activated by tension. As many as eight or nine linked or linkable equivalent conductance units or co-channels can open together. Open time for co-channel quadruplets and quintuplets tends to be relatively long with millimolar Mg2+ (but not millimolar Ca2+) at the cytosolic face of excised plasma membrane. Sensitivity to tension is regulated by transmembrane voltage and temperature. Under some circumstances channel activity is sychronized in rhythmic pulses. Certain lanthanides and a cytoskeleton-disturbing herbicide that inhibit gravitropic reception act on the channel system at low concentrations. Specifically, ethyl-N-phenylcarbamate promotes tension-dependent activity at micromolar levels. With moderate suction, Gd3+ provided at about 0.5 micromole at the extracellular face of the membrane promotes for several seconds but may then become inhibitory. Provision at 1-2 micromoles promotes and subsequently inhibits more vigorously (often abruptly and totally), and at high levels inhibits immediately. La3+, a poor gravitropic inhibitor, acts similarly but much more gradually and only at much higher concentrations. These properties, particularly these susceptibilities to modulation, indicate that in vivo the mechanosensitive channel must be mechanosensory and mechanoregulatory. It could serve to transduce the shear forces generated in the integrated wall-membrane-cytoskeleton system during turgor changes and cell expansion as well as transducing the stresses induced by gravity, touch and flexure. In so far as such transduction is modulated by voltage and temperature, the channels would also be sensors for these modalities as long as the wall-membrane-cytoskeleton system experiences mechanical stress.

  3. A Thieno[3,2-b][1]benzothiophene Isoindigo Building Block for Additive- and Annealing-Free High-Performance Polymer Solar Cells

    KAUST Repository

    Yue, Wan

    2015-08-20

    A novel photoactive polymer with two different molecular weights is reported, based on a new building block: thieno[3,2-b][1]benzothiophene isoindigo. Due to the improved crystallinity, optimal blend morphology, and higher charge mobility, solar-cell devices of the high-molecular-weight polymer exhibit a superior performance, affording efficiencies of 9.1% without the need for additives, annealing, or additional extraction layers during device fabrication.

  4. Thymic selection of T-cell receptors as an extreme value problem

    CERN Document Server

    Kosmrlj, Andrej; Kardar, Mehran; Shakhnovich, Eugene I

    2009-01-01

    T lymphocytes (T cells) orchestrate adaptive immune responses upon activation. T cell activation requires sufficiently strong binding of T cell receptors (TCRs) on their surface to short peptides (p) derived from foreign proteins, which are bound to major histocompatibility (MHC) gene products (displayed on antigen presenting cells). A diverse and self-tolerant T cell repertoire is selected in the thymus. We map thymic selection processes to an extreme value problem and provide an analytic expression for the amino acid compositions of selected TCRs (which enable its recognition functions).

  5. Selection of mutant Chinese hamster ovary cells altered glycoproteins by means of tritiated fucose suicide.

    OpenAIRE

    Hirschberg, C B; Baker, R.M.; Perez, M.; Spencer, L A; Watson, D

    1981-01-01

    Mutant Chinese hamster ovary cells altered in glycoproteins have been isolated by selecting for ability to survive exposure to [6-3H]fucose. Mutagenized wild-type cells were permitted to incorporate [3H]fucose to approximately 1 cpm of trichloroacetic acid-insoluble radioactivity per cell and then frozen for several days to accumulate radiation damage. The overall viability of the population was reduced by 5- to 50-fold. Four consecutive selection cycles were carried out. The surviving cells ...

  6. Cell surface thiol isomerases may explain the platelet-selective action of S-nitrosoglutathione

    OpenAIRE

    Xiao, Fang; Gordge, Michael P

    2011-01-01

    S-nitrosoglutathione (GSNO) at low concentration inhibits platelet aggregation without causing vasodilation, suggesting platelet-selective nitric oxide delivery. The mechanism of this selectivity is unknown, but may involve cell surface thiol isomerases, in particular protein disulphide isomerase (csPDI) (EC 5.3.4.1). We have now compared csPDI expression and activity on platelets, endothelial cells and vascular smooth muscle cells, and the dependence on thiol reductase activity of these cell...

  7. Resveratrol Sensitizes Selectively Thyroid Cancer Cell to 131-Iodine Toxicity

    Directory of Open Access Journals (Sweden)

    Seyed Jalal Hosseinimehr

    2014-01-01

    Full Text Available Background. In this study, the radiosensitizing effect of resveratrol as a natural product was investigated on cell toxicity induced by 131I in thyroid cancer cell. Methods. Human thyroid cancer cell and human nonmalignant fibroblast cell (HFFF2 were treated with 131I and/or resveratrol at different concentrations for 48 h. The cell proliferation was measured by determination of the percent of the survival cells using 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT assay. Results. Findings of this study show that resveratrol enhanced the cell death induced by 131I on thyroid cancer cell. Also, resveratrol exhibited a protective effect on normal cells against 131I toxicity. Conclusion. This result indicates a promising effect of resveratrol on improvement of cellular toxicity during iodine therapy.

  8. Gentamicin Blocks the ACh-Induced BK Current in Guinea Pig Type II Vestibular Hair Cells by Competing with Ca2+ at the l-Type Calcium Channel

    Directory of Open Access Journals (Sweden)

    Hong Yu

    2014-04-01

    Full Text Available Type II vestibular hair cells (VHCs II contain big-conductance Ca2+-dependent K+ channels (BK and L-type calcium channels. Our previous studies in guinea pig VHCs II indicated that acetylcholine (ACh evoked the BK current by triggering the influx of Ca2+ ions through l-type Ca2+ channels, which was mediated by M2 muscarinic ACh receptor (mAChRs. Aminoglycoside antibiotics, such as gentamicin (GM, are known to have vestibulotoxicity, including damaging effects on the efferent nerve endings on VHCs II. This study used the whole-cell patch clamp technique to determine whether GM affects the vestibular efferent system at postsynaptic M2-mAChRs or the membrane ion channels. We found that GM could block the ACh-induced BK current and that inhibition was reversible, voltage-independent, and dose-dependent with an IC50 value of 36.3 ± 7.8 µM. Increasing the ACh concentration had little influence on GM blocking effect, but increasing the extracellular Ca2+ concentration ([Ca2+]o could antagonize it. Moreover, 50 µM GM potently blocked Ca2+ currents activated by (--Bay-K8644, but did not block BK currents induced by NS1619. These observations indicate that GM most likely blocks the M2 mAChR-mediated response by competing with Ca2+ at the l-type calcium channel. These results provide insights into the vestibulotoxicity of aminoglycoside antibiotics on mammalian VHCs II.

  9. Prostacyclin Inhibits Non-Small Cell Lung Cancer Growth by a Frizzled 9-Dependent Pathway That Is Blocked by Secreted Frizzled-Related Protein 1

    Directory of Open Access Journals (Sweden)

    Meredith A. Tennis

    2010-03-01

    Full Text Available The goal of this study was to assess the ability of iloprost, an orally active prostacyclin analog, to inhibit transformed growth of human non-small cell lung cancer (NSCLC and to define the mechanism of iloprost's tumor suppressive effects. In a panel of NSCLC cell lines, the ability of iloprost to inhibit transformed cell growth was not correlated with the expression of the cell surface receptor for prostacyclin, but instead was correlated with the presence of Frizzled 9 (Fzd 9 and the activation of peroxisome proliferator-activated receptor-γ (PPARγ. Silencing of Fzd 9 blocked PPARγ activation by iloprost, and expression of Fzd 9 in cells lacking the protein resulted in iloprost's activation of PPARγ and inhibition of transformed growth. Interestingly, soluble Frizzled-related protein-1, a well-known inhibitor of Wnt/Fzd signaling, also blocked the effects of iloprost and Fzd 9. Moreover, mice treated with iloprost had reduced lung tumors and increased Fzd 9 expression. These studies define a novel paradigm, linking the eicosanoid pathway and Wnt signaling. In addition, these data also suggest that prostacyclin analogs may represent a new class of therapeutic agents in the treatment of NSCLC where the restoration of noncanonical Wnt signaling maybe important for the inhibition of transformed cell growth.

  10. Thymoproteasomes produce unique peptide motifs for positive selection of CD8(+) T cells.

    Science.gov (United States)

    Sasaki, Katsuhiro; Takada, Kensuke; Ohte, Yuki; Kondo, Hiroyuki; Sorimachi, Hiroyuki; Tanaka, Keiji; Takahama, Yousuke; Murata, Shigeo

    2015-01-01

    Positive selection in the thymus provides low-affinity T-cell receptor (TCR) engagement to support the development of potentially useful self-major histocompatibility complex class I (MHC-I)-restricted T cells. Optimal positive selection of CD8(+) T cells requires cortical thymic epithelial cells that express β5t-containing thymoproteasomes (tCPs). However, how tCPs govern positive selection is unclear. Here we show that the tCPs produce unique cleavage motifs in digested peptides and in MHC-I-associated peptides. Interestingly, MHC-I-associated peptides carrying these tCP-dependent motifs are enriched with low-affinity TCR ligands that efficiently induce the positive selection of functionally competent CD8(+) T cells in antigen-specific TCR-transgenic models. These results suggest that tCPs contribute to the positive selection of CD8(+) T cells by preferentially producing low-affinity TCR ligand peptides.

  11. Chrysin inhibits tumor promoter-induced MMP-9 expression by blocking AP-1 via suppression of ERK and JNK pathways in gastric cancer cells.

    Directory of Open Access Journals (Sweden)

    Yong Xia

    Full Text Available Cell invasion is a crucial mechanism of cancer metastasis and malignancy. Matrix metalloproteinase-9 (MMP-9 is an important proteolytic enzyme involved in the cancer cell invasion process. High expression levels of MMP-9 in gastric cancer positively correlate with tumor aggressiveness and have a significant negative correlation with patients' survival times. Recently, mechanisms suppressing MMP-9 by phytochemicals have become increasingly investigated. Chrysin, a naturally occurring chemical in plants, has been reported to suppress tumor metastasis. However, the effects of chrysin on MMP-9 expression in gastric cancer have not been well studied. In the present study, we tested the effects of chrysin on MMP-9 expression in gastric cancer cells, and determined its underlying mechanism. We examined the effects of chrysin on MMP-9 expression and activity via RT-PCR, zymography, promoter study, and western blotting in human gastric cancer AGS cells. Chrysin inhibited phorbol-12-myristate 13-acetate (PMA-induced MMP-9 expression in a dose-dependent manner. Using AP-1 decoy oligodeoxynucleotides, we confirmed that AP-1 was the crucial transcriptional factor for MMP-9 expression. Chrysin blocked AP-1 via suppression of the phosphorylation of c-Jun and c-Fos through blocking the JNK1/2 and ERK1/2 pathways. Furthermore, AGS cells pretreated with PMA showed markedly enhanced invasiveness, which was partially abrogated by chrysin and MMP-9 antibody. Our results suggest that chrysin may exert at least part of its anticancer effect by controlling MMP-9 expression through suppression of AP-1 activity via a block of the JNK1/2 and ERK1/2 signaling pathways in gastric cancer AGS cells.

  12. Selective assembly of laminin variants by human carcinoma cells

    DEFF Research Database (Denmark)

    Wewer, U M; Wayner, E A; Hoffstrom, B G;

    1994-01-01

    in negligible amounts as detected by Northern blotting and PCR. The only exception was the HU-1 lung adenocarcinoma cell line which expressed significant quantities of laminin M chain mRNA and lower levels of laminin A chain mRNA. The presence in the HU-1 cells of translated polypeptides was demonstrated...... cell lines produced laminin chains B1, B2 and S, but no or little A or M. The only exception was the lung carcinoma cell line HU-1. Human HU-1 carcinoma cells in culture synthesize several homologous laminin chains and regulate the process of assembly, secretion and deposition of laminin variants...

  13. Recruitment and selection of marginal zone B cells is independent of exogenous antigens

    NARCIS (Netherlands)

    Dammers, PM; Kroese, FGM

    2005-01-01

    Marginal zone B (MZ-B) cells of the spleen contribute significantly to the immunity against invasive infections with polysaccharide-encapsulated bacteria. Recent evidence indicates that recruitment and selection of MZ-B cells occurs on the basis of positive selection constraints that likely operate

  14. Phytohemagglutinin-induced change in the distribution of acidic sugars in surface membrane of lymphoid cells and blocking of the radiation effect. [X radiation

    Energy Technology Data Exchange (ETDEWEB)

    Sato, C.; Kojima, K.

    1976-01-01

    Cell electrophoretic mobilities (EPM) of cultured lymphoblastoid cells were measured after removal of acidic sugars to investigate whether the localization of these acidic sugars was altered by the action of phytohaemagglutinin (PHA). After treatment with neuraminidase or hyaluronidase, the EPM of control cells decreased 50.1 and 0.3 percent, while that of PHA-treated cells decreased 25.2 and 39.0 percent, respectively. These results suggest that hyaluronic acid appeared at the periphery of the cell surface in place of some sialic acid after incubation with PHA. The change became evident after 10 min incubation with PHA and reached its maximum after 20 min at 37/sup 0/C, but no change was observed at 4/sup 0/C. The EPM decreased with time after x-irradiation, and reached a minimum value after 4 h. The addition of PHA to culture before irradiation completely blocked the x-ray mediated reduction in EPM. PHA administration after irradiation stopped further EPM reduction. These results seem to suggest a rapid rearrangement of membrane molecules linking with the receptors and acidic sugars induced by PHA, and blocking of further conformation change by x-irradiation.

  15. Phytohemagglutinin-induced change in the distribution of acidic sugars in surface membrane of lymphoid cells and blocking of the radiation effect

    International Nuclear Information System (INIS)

    Cell electrophoretic mobilities (EPM) of cultured lymphoblastoid cells were measured after removal of acidic sugars to investigate whether the localization of these acidic sugars was altered by the action of phytohaemagglutinin (PHA). After treatment with neuraminidase or hyaluronidase, the EPM of control cells decreased 50.1 and 0.3 percent, while that of PHA-treated cells decreased 25.2 and 39.0 percent, respectively. These results suggest that hyaluronic acid appeared at the periphery of the cell surface in place of some sialic acid after incubation with PHA. The change became evident after 10 min incubation with PHA and reached its maximum after 20 min at 370C, but no change was observed at 40C. The EPM decreased with time after x-irradiation, and reached a minimum value after 4 h. The addition of PHA to culture before irradiation completely blocked the x-ray mediated reduction in EPM. PHA administration after irradiation stopped further EPM reduction. These results seem to suggest a rapid rearrangement of membrane molecules linking with the receptors and acidic sugars induced by PHA, and blocking of further conformation change by x-irradiation

  16. Hematopoietic stem cell transplantation in sickle cell disease: patient selection and special considerations

    Directory of Open Access Journals (Sweden)

    Bhatia M

    2015-07-01

    be donors. Matched siblings should be referred to an experienced transplant center for evaluation and counseling. In this review, we will discuss the rationale for these opinions and make recommendations for patient selection.Keywords: sickle cell disease, morbidity, stem cell transplantation, patient selection, matched sibling donor

  17. Emprego do cell block de agarose como método complementar no diagnóstico citológico de tumores mamários caninos Employment of cell block of agarose as additional method in the cytological diagnosis of canine mammary tumors

    Directory of Open Access Journals (Sweden)

    Diogo Sousa Zanoni

    2013-03-01

    Full Text Available Os tumores mamários são neoplasias comuns em diversas espécies, sendo os processos oncológicos de maior incidência em cães. A elevada frequência e agressividade desses processos justificam a busca de métodos diagnósticos e prognósticos rápidos, de custo reduzido e menor invasividade, visando a uma abordagem cirúrgica e terapêutica adequada. O presente estudo avaliou a adequação da utilização da técnica de cell block de agarose como método diagnóstico complementar aos esfregaços tradicionais no diagnóstico desses processos. Para tanto, foram obtidas 51 amostras citológicas de tumores mamários de 30 cadelas que passaram por excisão tumoral no HOVET-UMESP, comparando-se os resultados obtidos a partir dos esfregaços, de cell blocks, e de sua associação (esfregaços cell blocks-1 com o diagnóstico histopatológico. Os melhores resultados foram obtidos mediante a associação dos métodos, reduzindo os resultados falso-negativos e elevando a correlação cito-histológica, reforçando a importância da citologia na rotina oncológica veterinária.The breast tumors are common neoplasms in several species, with high incidence in dogs. The high frequency and aggressiveness of these cases justifies the search for rapid, low cost and less invasive diagnostic methods, seeking for surgical approach and appropriate therapy. This study evaluated the appropriateness of the use of the agarose cell block technique as a diagnostic tool to complement traditional smears in the diagnosis of these processes. Therefore, it was obtained 51 samples from 30 dogs with breast tumors that underwent tumoral excision at the HOVET-UMESP, comparing the results obtained from smears, cell blocks, alone and in association (smears cell blocks-1, with the histopathologic diagnosis. The best results were obtained with the association of smears and cell block analysis, reducing the false negative results and increasing the cyto-histological correlation

  18. New Strategies for Designing Inexpensive but Selective Bioadsorbants for Environmental Pollutants: Selection of specific Ligands and Their Cell Surface Expression

    Energy Technology Data Exchange (ETDEWEB)

    Brent L. Iverson; George Georgiou; Mohammad M. Ataai; Richard R. Koepsel

    2001-02-22

    The Broad, long term objective of the research plan is to develop exquisitely selective polypeptide metal chelators for the remediation of aqueous systems. A variety of polypeptide chelators will be developed and optimized ranging from antibodies to small peptides. Then, through unique molecular engineering approaches developed in our laboratories, the polypeptide chelators will be anchored directly on the surface of the cells that produce them. Thus, instead of using isolated biomolecules we will employ inexpensive genetically engineered whole cell adsorbents. Following a simple, easily scaleable treatment, the engineered cells can be used to manufacture an inexpensive, particulate adsorbent for metal removal.

  19. Staining plastic blocks with triiodide to image cells and soft tissues in backscattered electron SEM of skeletal and dental tissues.

    Science.gov (United States)

    Boyde, A

    2012-01-01

    Backscattered electron scanning electron microscopy (BSE SEM) is an invaluable method for studying the histology of the hard, mineralised components of poly-methyl methacrylate (PMMA) or other resin embedded skeletal and dental tissues. Intact tissues are studied in micro-milled or polished block faces with an electron-optical section thickness of the order of a half to one micron and with the area of the section as big as a whole--large or small--bone organ. However, BSE SEM does not give information concerning the distribution of uncalcified, 'soft', cellular and extracellular matrix components. This can be obtained by confocal microscopy of the same block and the two sorts of images merged but the blocks have to be studied in two microscope systems. The present work shows a new, simple and economic approach to visualising both components by using the triiodide ion in Lugol's iodine solution to stain the block surface prior to the application of any conductive coating--and the latter can be omitted if charging is suppressed by use of poor vacuum conditions in the SEM sample chamber. The method permits the use of archival tissue, and it will be valuable in studies of both normal growth and development and pathological changes in bones and joints, including osteoporosis and osteoarthritis, and tissue adaptation to implants. PMID:22828992

  20. Losartan sensitizes selectively prostate cancer cell to ionizing radiation.

    Science.gov (United States)

    Yazdannejat, H; Hosseinimehr, S J; Ghasemi, A; Pourfallah, T A; Rafiei, A

    2016-01-11

    Losartan is an angiotensin II receptor (AT-II-R) blocker that is widely used by human for blood pressure regulation. Also, it has antitumor property. In this study, we investigated the radiosensitizing effect of losartan on cellular toxicity induced by ionizing radiation on prostate cancer and non-malignant fibroblast cells. Human prostate cancer (DU-145) and human non-malignant fibroblast cells (HFFF2) were treated with losartan at different concentrations (0.5, 1, 10, 50 and 100 µM) and then these cells were exposed to ionizing radiation. The cell proliferation was determined using MTT assay. Our results showed that losartan exhibited antitumor effect on prostate cancer cells; it was reduced cell survival to 66% at concentration 1 µM. Losartan showed an additive killing effect in combination with ionizing radiation on prostate cancer cell. The cell proliferation was reduced to 54% in the prostate cancer cells treated with losartan at concentration 1 µM in combination with ionizing radiation. Losartan did not exhibit any toxicity on HFFF2 cell. This result shows a promising effect of losartan on enhancement of therapeutic effect of ionizing radiation in patients during therapy.

  1. Resveratrol engages selective apoptotic signals in gastric adenocarcinoma cells

    Institute of Scientific and Technical Information of China (English)

    William L Riles; Jason Erickson; Sanjay Nayyar; Mary Jo Atten; Bashar M Attar; Oksana Holian

    2006-01-01

    AIM: To investigate the intracellular apoptotic signals engaged by resveratrol in three gastric adenocarcinoma cancer cell lines, two of which (AGS and SNU-1) express p53 and one (KATO-Ⅲ) with deleted p53.METHODS: Nuclear fragmentation was used to quantitate apoptotic cells; caspase activity was determined by photometric detection of cleaved substrates; formation of oxidized cytochrome C was used to measure cytochrome C activity, and Western blot analysis was used to determine protein expression.RESULTS: Gastric cancer cells, irrespective of their p53 status, responded to resveratrol with fragmentation of DNA and cleavage of nuclear lamins A and B and PARP, Resveratrol, however, has no effect on mitochondria-associated apoptotic proteins Bcl-2, Bclxl, Bax, Bid or Smac/Diablo, and did not promote subcellular redistribution of cytochrome C, indicating that resveratrol-induced apoptosis of gastric carcinoma cells does not require breakdown of mitochondrial membrane integrity. Resveratrol up-regulated p53 protein in SNU-1 and AGS cells but there was a difference in response of intracellular apoptotic signals between these cell lines.SNU-1 cells responded to resveratrol treatment with down-regulation of survivin, whereas in AGS and KATO-Ⅲ cells resveratrol stimulated caspase 3 and cytochrome C oxidase activities.CONCLUSION: These findings indicate that even within a specific cancer the intracellular apoptotic signals engaged by resveratrol are cell type dependent and suggest that such differences may be related to differentiation or lack of differentiation of these cells.

  2. Influence of 1,2-PB matrix cross-linking on structure and properties of selectively etched 1,2-PB-b-PDMS block copolymers

    DEFF Research Database (Denmark)

    Guo, Fengxiao; Andreasen, Jens Wenzel; Vigild, Martin Etchells;

    2007-01-01

    cross-linked samples in toluene was converted into a degree of cross-linking following the Flory scheme; a simple relation between the Flory cross-linking degree and the fraction of consumed double bonds during the cross-linking reaction followed. The structure of the block copolymer at different stages...

  3. A complex extracellular sphingomyelinase of Pseudomonas aeruginosa inhibits angiogenesis by selective cytotoxicity to endothelial cells.

    Directory of Open Access Journals (Sweden)

    Michael L Vasil

    2009-05-01

    Full Text Available The hemolytic phospholipase C (PlcHR expressed by Pseudomonas aeruginosa is the original member of a Phosphoesterase Superfamily, which includes phosphorylcholine-specific phospholipases C (PC-PLC produced by frank and opportunistic pathogens. PlcHR, but not all its family members, is also a potent sphingomyelinase (SMase. Data presented herein indicate that picomolar (pM concentrations of PlcHR are selectively lethal to endothelial cells (EC. An RGD motif of PlcHR contributes to this selectivity. Peptides containing an RGD motif (i.e., GRGDS, but not control peptides (i.e., GDGRS, block the effects of PlcHR on calcium signaling and cytotoxicity to EC. Moreover, RGD variants of PlcHR (e.g., RGE, KGD are significantly reduced in their binding and toxicity, but retain the enzymatic activity of the wild type PlcHR. PlcHR also inhibits several EC-dependent in vitro assays (i.e., EC migration, EC invasion, and EC tubule formation, which represent key processes involved in angiogenesis (i.e., formation of new blood vessels from existing vasculature. Finally, the impact of PlcHR in an in vivo model of angiogenesis in transgenic zebrafish, and ones treated with an antisense morpholino to knock down a key blood cell regulator, were evaluated because in vitro assays cannot fully represent the complex processes of angiogenesis. As little as 2 ng/embryo of PlcHR was lethal to approximately 50% of EGFP-labeled EC at 6 h after injection of embryos at 48 hpf (hours post-fertilization. An active site mutant of PlcHR (Thr178Ala exhibited 120-fold reduced inhibitory activity in the EC invasion assay, and 20 ng/embryo elicited no detectable inhibitory activity in the zebrafish model. Taken together, these observations are pertinent to the distinctive vasculitis and poor wound healing associated with P. aeruginosa sepsis and suggest that the potent antiangiogenic properties of PlcHR are worthy of further investigation for the treatment of diseases where

  4. Selective cytotoxicity of benzyl isothiocyanate in the proliferating fibroblastoid cells.

    Science.gov (United States)

    Miyoshi, Noriyuki; Uchida, Koji; Osawa, Toshihiko; Nakamura, Yoshimasa

    2007-02-01

    In the present study, experiments using presynchronization culture cells demonstrated that benzyl ITC (BITC), previously isolated from a tropical papaya fruit extract, induced the cytotoxic effect preferentially in the proliferating human colon CCD-18Co cells to the quiescent ones. Quiescent CCD-18Co cells were virtually unaffected by BITC and marginal cytotoxicity was observed at 15 microM. We observed that BITC dramatically induced the p53 phosphorylation and stabilization only in the quiescent (G(0)/G(1) phase-arrested) cells, but not significantly in the proliferating human colon CCD-18Co cells when compared with quiescent ones. We also observed ataxia telangiectasia-mutated (ATM) phosphorylation in the quiescent cells. The BITC-induced p53 phosphorylation was counteracted by caffeine treatment, implying the involvement of an ATM/ataxia telangiectasia and Rad3-related kinase signaling pathway. Moreover, downregulation of p53 by a siRNA resulted in the enhancement of susceptibility to undergo apoptosis by BITC. We also showed here that depletion of p53 abrogated G(0)/G(1) arrest accompanied by the declined expression of p21(waf1/cip1) and p27(kip1) in CCD-18Co cells. In conclusion, we identified p53 as a potential negative regulator of the apoptosis induction by BITC in the normal colon CCD-18Co cells through the inhibition of cell-cycle progression at the G(0)/G(1) phase. PMID:17096346

  5. Tumor-associated mesenchymal stem cells inhibit naïve T cell expansion by blocking cysteine export from dendritic cells.

    Science.gov (United States)

    Ghosh, Tithi; Barik, Subhasis; Bhuniya, Avishek; Dhar, Jesmita; Dasgupta, Shayani; Ghosh, Sarbari; Sarkar, Madhurima; Guha, Ipsita; Sarkar, Koustav; Chakrabarti, Pinak; Saha, Bhaskar; Storkus, Walter J; Baral, Rathindranath; Bose, Anamika

    2016-11-01

    Mesenchymal stem cells (MSCs) represent an important cellular constituent of the tumor microenvironment, which along with tumor cells themselves, serve to regulate protective immune responses in support of progressive disease. We report that tumor MSCs prevent the ability of dendritic cells (DC) to promote naïve CD4(+) and CD8(+) T cell expansion, interferon gamma secretion and cytotoxicity against tumor cells, which are critical to immune-mediated tumor eradication. Notably, tumor MSCs fail to prevent DC-mediated early T cell activation events or the ability of responder T cells to produce IL-2. The immunoregulatory activity of tumor MSCs is IL-10- and STAT3-dependent, with STAT3 repressing DC expression of cystathionase, a critical enzyme that converts methionine-to-cysteine. Under cysteine-deficient priming conditions, naïve T cells exhibit defective cellular metabolism and proliferation. Bioinformatics analyses as well as in vitro observations suggest that STAT3 may directly bind to a GAS-like motif within the cystathionase promoter (-269 to -261) leading to IL-10-STAT3 mediated repression of cystathionase gene transcription. Our collective results provide evidence for a novel mechanism of tumor MSC-mediated T cell inhibition within tumor microenvironment. PMID:27405489

  6. Involvement of Tspan8 in exosome assembly and target cell selection

    OpenAIRE

    Rana, Sanyukta

    2010-01-01

    Exosomes are the most important intercellular communicators. Tetraspanins/their complexes are suggested to be important in exosomal target cell selection. I showed: changes in Tetraspanin8 associations created from internalization persist upto exosomes and, differences in tetraspanin-complexes on exosomes allow for target cell selectivity.Based on the tetraspanin-complex on exosomes, predictions on potential target cells might be possible, allowing tailored exosome generation for drug delivery.

  7. Layer-by-Layer Formation of Block-Copolymer-Derived TiO2 for Solid-State Dye-Sensitized Solar Cells

    KAUST Repository

    Guldin, Stefan

    2011-12-15

    Morphology control on the 10 nm length scale in mesoporous TiO 2 films is crucial for the manufacture of high-performance dye-sensitized solar cells. While the combination of block-copolymer self-assembly with sol-gel chemistry yields good results for very thin films, the shrinkage during the film manufacture typically prevents the build-up of sufficiently thick layers to enable optimum solar cell operation. Here, a study on the temporal evolution of block-copolymer-directed mesoporous TiO 2 films during annealing and calcination is presented. The in-situ investigation of the shrinkage process enables the establishment of a simple and fast protocol for the fabrication of thicker films. When used as photoanodes in solid-state dye-sensitized solar cells, the mesoporous networks exhibit significantly enhanced transport and collection rates compared to the state-of-the-art nanoparticle-based devices. As a consequence of the increased film thickness, power conversion efficiencies above 4% are reached. Fabrication of sufficiently thick mesoporous TiO 2 photoelectrodes with morphology control on the 10 nm length scale is essential for solid-state dye-sensitized solar cells (ss-DSC). This study of the temporal evolution of block-copolymer-directed mesoporous TiO 2 films during annealing and calcination enables the build-up of sufficiently thick films for high-performance ssDSC devices. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Withaferin A Induces Cell Death Selectively in Androgen-Independent Prostate Cancer Cells but Not in Normal Fibroblast Cells.

    Directory of Open Access Journals (Sweden)

    Yukihiro Nishikawa

    Full Text Available Withaferin A (WA, a major bioactive component of the Indian herb Withania somnifera, induces cell death (apoptosis/necrosis in multiple types of tumor cells, but the molecular mechanism underlying this cytotoxicity remains elusive. We report here that 2 μM WA induced cell death selectively in androgen-insensitive PC-3 and DU-145 prostate adenocarcinoma cells, whereas its toxicity was less severe in androgen-sensitive LNCaP prostate adenocarcinoma cells and normal human fibroblasts (TIG-1 and KD. WA also killed PC-3 cells in spheroid-forming medium. DNA microarray analysis revealed that WA significantly increased mRNA levels of c-Fos and 11 heat-shock proteins (HSPs in PC-3 and DU-145, but not in LNCaP and TIG-1. Western analysis revealed increased expression of c-Fos and reduced expression of the anti-apoptotic protein c-FLIP(L. Expression of HSPs such as HSPA6 and Hsp70 was conspicuously elevated; however, because siRNA-mediated depletion of HSF-1, an HSP-inducing transcription factor, reduced PC-3 cell viability, it is likely that these heat-shock genes were involved in protecting against cell death. Moreover, WA induced generation of reactive oxygen species (ROS in PC-3 and DU-145, but not in normal fibroblasts. Immunocytochemistry and immuno-electron microscopy revealed that WA disrupted the vimentin cytoskeleton, possibly inducing the ROS generation, c-Fos expression and c-FLIP(L suppression. These observations suggest that multiple events followed by disruption of the vimentin cytoskeleton play pivotal roles in WA-mediated cell death.

  9. SELECTING THE DIRECTION FOR TECHNICAL RE-EQUIPMENT OF THE TPP OIL-GAS BLOCKS OF 300 MW CAPACITY IN THE COUNTRIES OF THE EAST-EUROPEAN REGION

    Directory of Open Access Journals (Sweden)

    V. M. Neuimin

    2015-01-01

    Full Text Available The author presents analysis of renovation variants for 300 MW oil-gas power blocks: substitution of the steam-power energy blocks by those with gas-steam cycle units, technical re-equipment of the energy blocks by means of reconstruction or modernization of the steam turbine, substitution implementation of the steam turbine with an analogous new one, prolongation of the operation life of the equipment in service. Renovation variants for the power blocks of the specified type in the TPPs of Russia can be chosen based on various engineering solutions concluded on the following grounds: mediumand long-term perspectives of their fuel balance structure (natural gas, synthetic gas fuel-oil residual, pulverized coal fuel including clean-coal and coal-benefication production wastes; the demands laid by JSC the JI UES on the participation of power blocks in frequency regulation and node inter-flow; development in the country of the distributed generation and the perspectives associated with it of the reconstructed TPPs installed capacity utilization in corresponding power-grid nodes; the development of related industries of the country’s economy; the speed of mastering the eco-friendly homegrown steam-gas and coal technologies; creation of the competitive national element base of microelectronics.Introduction of foreign steam-gas generators in this country requires development of the repair-and-service maintenance, provokes elevated risks and tangible costs, conduces to level decrease in the energy and national safety of the state. Orientation of the country’s power engineers to foreign gas-turbines of large single-unit capacity does not contribute to domestic power-plant industry development. With the view of reduction in value of the TPP-equipment by 12–15 %, it is prudent for power engineers to form a perspective manufacturing order for the period after 2016. In light of emerging political and economic situation in the world, technical re

  10. Thymic Selection of T-Cell Receptors as an Extreme Value Problem

    Science.gov (United States)

    Kosmrlj, Andrej; Chakraborty, Arup K.; Kardar, Mehran; Shakhnovich, Eugene I.

    2010-03-01

    T lymphocytes (T cells) orchestrate adaptive immune responses that clear pathogens from infected hosts. T cells recognize short peptides (p) derived from foreign proteins, which are bound to major histocompatibility complex (MHC) gene products (displayed on antigen- presenting cells). Recognition occurs when T cell receptor (TCR) proteins expressed on T cells bind sufficiently strongly to antigen- derived pMHC complexes on the surface of antigen-presenting cells. A diverse repertoire of self-tolerant TCR sequences is shaped during development of T cells in the thymus by processes called positive and negative selection. We map thymic selection processes to an extreme value problem and provide analytic expression for the amino acid composition of selected TCR sequences (which enable its recognition functions).

  11. A novel anti-EMMPRIN function-blocking antibody reduces T cell proliferation and neurotoxicity: relevance to multiple sclerosis

    OpenAIRE

    Agrawal Smriti M; Silva Claudia; Wang Janet; Tong Jade; Yong V

    2012-01-01

    Abstract Background Extracellular matrix metalloproteinase inducer (EMMPRIN; CD147, basigin) is an inducer of the expression of several matrix metalloproteinases (MMPs). We reported previously that blocking EMMPRIN activity reduced neuroinflammation and severity of disease in an animal model of multiple sclerosis (MS), experimental autoimmune encephalomyelitis (EAE). Methods To improve upon EMMPRIN blockade, and to help unravel the biological functions of EMMPRIN in inflammatory disorders, we...

  12. The Human Homolog of Drosophila Headcase Acts as a Tumor Suppressor through Its Blocking Effect on the Cell Cycle in Hepatocellular Carcinoma.

    Directory of Open Access Journals (Sweden)

    Jun Wang

    Full Text Available The molecular pathogenesis of hepatocellular carcinoma (HCC is heterogeneous and extremely complex. Thus, for individual molecular targeted therapy, novel molecular markers are needed. The abnormal expression of the human homolog of Drosophila headcase (HECA homo has been found in pancreatic, colorectal, and oral squamous cell carcinoma. Studies of oral squamous cell carcinoma have also demonstrated that the HECA homo protein can be negatively controlled by the Wnt-pathway and transcription factor 4 (TCF4 and can slow cell division by interacting with cyclins and CDKs. However, the role of HECA in HCC has not been reported elsewhere. Here, immunohistochemical analysis revealed that the downregulation of HECA homo protein occurred in 71.0% (66/93 of HCC cases and was positively correlated with a poorly differentiated grade, high serum AFP level, liver cirrhosis and large tumor size. The expression of HECA homo was detected in five live cell lines. In vitro, the overexpression of HECA homo in HepG2, Huh-7 and MHCC-97H cells could inhibit cell proliferation and colony formation and induce G1 phase arrest. In contrast, the downregulation of HECA homo could promote cell proliferation, colony formation and the cell cycle process. However, neither the overexpression nor downregulation of HECA homo in the three cell lines could affect cell migration or invasion. Collectively, HECA homo is regularly expressed in normal live cells, and the HECA homo protein level is heterogeneously altered in HCC, but the downregulation of HECA homo is more common and positively correlated with several malignant phenotypes. The HECA homo protein can slow cell proliferation to some extent primarily through its blocking effect on the cell cycle. Hence, the HECA homo protein may act as a tumor suppressor in HCC and might be a potential molecular marker for diagnostic classification and targeted therapy in HCC.

  13. Double suicide genes selectively kill human umbilical vein endothelial cells

    Directory of Open Access Journals (Sweden)

    Liu Lunxu

    2011-02-01

    Full Text Available Abstract Background To construct a recombinant adenovirus containing CDglyTK double suicide genes and evaluate the killing effect of the double suicide genes driven by kinase domain insert containing receptor (KDR promoter on human umbilical vein endothelial cells. Methods Human KDR promoter, Escherichia coli (E. coli cytosine deaminase (CD gene and the herpes simplex virus-thymidine kinase (TK gene were cloned using polymerase chain reaction (PCR. Plasmid pKDR-CDglyTK was constructed with the KDR promoter and CDglyTK genes. A recombinant adenoviral plasmid AdKDR-CDglyTK was then constructed and transfected into 293 packaging cells to grow and harvest adenoviruses. KDR-expressing human umbilical vein endothelial cells (ECV304 and KDR-negative liver cancer cell line (HepG2 were infected with the recombinant adenoviruses at different multiplicity of infection (MOI. The infection rate was measured by green fluorescent protein (GFP expression. The infected cells were cultured in culture media containing different concentrations of prodrugs ganciclovir (GCV and/or 5-fluorocytosine (5-FC. The killing effects were measured using two different methods, i.e. annexin V-FITC staining and terminal transferase-mediated dUTP nick end-labeling (TUNEL staining. Results Recombinant adenoviruses AdKDR-CDglyTK were successfully constructed and they infected ECV304 and HepG2 cells efficiently. The infection rate was dependent on MOI of recombinant adenoviruses. ECV304 cells infected with AdKDR-CDglyTK were highly sensitive to GCV and 5-FC. The cell survival rate was dependent on both the concentration of the prodrugs and the MOI of recombinant adenoviruses. In contrast, there were no killing effects in the HepG2 cells. The combination of two prodrugs was much more effective in killing ECV304 cells than GCV or 5-FC alone. The growth of transgenic ECV304 cells was suppressed in the presence of prodrugs. Conclusion AdKDR-CDglyTK/double prodrog system may be a useful

  14. Synthesis of a selectively protected trisaccharide building block of the capsular polysaccharide of Streptococcus pneumoniae types 6A and 6B

    NARCIS (Netherlands)

    Vliegenthart, J.F.G.; Slaghek, T.M.; Vliet, M.J. van; Maas, A.A.M.; Kamerling, J.P.

    1989-01-01

    4-Methoxybenzyl 2,4-di-O-benzyl-3-O-[2,4,6-tri-O-benzyl-3-O-(3,4,6-tri-O-benzyl-α-D-galactopyranosyl)-α-D- glucopyranosyl]-α-L-rhamnopyranoside (22), a building block for the α-D-Galp-(1->3)-α-D-Glcp-(1->3)-α-L-Rhap fragment of the capsular polysaccharides of Streptococcus pneumoniae types 6A and 6B

  15. Selective stimulation of prostatic carcinoma cell proliferation by transferrin.

    OpenAIRE

    M.C. Rossi; Zetter, B R

    1992-01-01

    Aggressive prostatic carcinomas most frequently metastasize to the skeletal system. We have previously shown that cultured human prostatic carcinoma cells are highly responsive to growth factors found in human bone marrow. To identify the factor(s) responsible for the increased prostatic carcinoma cell proliferation, we fractionated crude bone marrow preparations by using hydroxylapatite HPLC. The major activity peak contained two high molecular weight bands (M(r) = 80,000 and 69,000) that cr...

  16. Intracellular delivery of cell-penetrating peptide-transcriptional factor fusion protein and its role in selective osteogenesis

    Directory of Open Access Journals (Sweden)

    Suh JS

    2014-03-01

    Full Text Available Jin Sook Suh,1,* Jue Yeon Lee,2,* Yoon Jung Choi,1 Hyung Keun You,3 Seong-Doo Hong,4 Chong Pyoung Chung,2 Yoon Jeong Park1,2 1Dental Regenerative Biotechnology, Dental Research Institute, School of Dentistry, Seoul National University, Seoul, 2Central Research Institute, Nano Intelligent Biomedical Engineering Corporation (NIBEC, Seoul, 3Department of Periodontology, College of Dentistry, Wonkwang University, Iksan, 4Department of Oral Pathology, School of Dentistry, Seoul National University, Seoul, Republic of Korea *These authors contributed equally to this work Abstract: Protein-transduction technology has been attempted to deliver macromolecular materials, including protein, nucleic acids, and polymeric drugs, for either diagnosis or therapeutic purposes. Herein, fusion protein composed of an arginine-rich cell-penetrating peptide, termed low-molecular-weight protamine (LMWP, and a transcriptional coactivator with a PDZ-binding motif (TAZ protein was prepared and applied in combination with biomaterials to increase bone-forming capacity. TAZ has been recently identified as a specific osteogenic stimulating transcriptional coactivator in human mesenchymal stem cell (hMSC differentiation, while simultaneously blocking adipogenic differentiation. However, TAZ by itself cannot penetrate the cells, and thus needs a transfection tool for translocalization. The LMWP-TAZ fusion proteins were efficiently translocalized into the cytosol of hMSCs. The hMSCs treated with cell-penetrating LMWP-TAZ exhibited increased expression of osteoblastic genes and protein, producing significantly higher quantities of mineralized matrix compared to free TAZ. In contrast, adipogenic differentiation of the hMSCs was blocked by treatment of LMWP-TAZ fusion protein, as reflected by reduced marker-protein expression, adipocyte fatty acid-binding protein 2, and peroxisome proliferator-activated receptor-γ messenger ribonucleic acid levels. LMWP-TAZ was applied in

  17. Single-chain antibody-based gene therapy: Inhibition of tumor growth by in situ production of phage-derived antibodies blocking functionally active sites of cell-associated matrices

    DEFF Research Database (Denmark)

    Sanz, Laura; Kristensen, Peter; Blanco, Belén;

    2002-01-01

    Experimental evidence suggests that blocking the interactions between endothelial cells and extracellular matrix (ECM) components may provide a potent and general strategy to inhibit tumor neovascularization. Based on these considerations, we have focused our efforts on laminin, component of the ...

  18. A selective tropism of transfused oval cells for liver

    Institute of Scientific and Technical Information of China (English)

    Jian-Zhi Chen; Hai Hong; Jin Xiang; Ling Xue; Guo-Qiang Zhao

    2003-01-01

    AIM: To explore the biological behaviors of hepatic oval cells after transfused into the circulation of experimental animals.METHODS: Oval cells from male SD rat were transfused into the circulation of a female rat which were treated by a 2-AAF/CCl4 program, through caudal vein. Sex-determining gene sry which located on Y chromosome was examined by PCR and in situ hybridization technique in liver, kidney and spleen of the experimental animals, respectively.RESULTS: The results of the cell-transplant experiment showed that the srygene was detectable only in the liver but not in spleen and kidney of the experimental rats, and no signals could be detected in the control animals. It can be also morphologically proved that some exogenous cells had migrated into the parenchyma of the liver and settled there.CONCLUSION: The result means that there are exogenous cells located in the liver of the experimental animal and the localization is specific to the liver. This indicates that some "signal molecules" must exist in the circulation of the rats treated by 2-AAF/CCl4. These "signal molecules" might play an important role in specific localization and differentiation of transfused oval cells.

  19. Engineering of Targeted Nanoparticles for Cancer Therapy Using Internalizing Aptamers Isolated by Cell-Uptake Selection

    Science.gov (United States)

    Xiao, Zeyu; Levy-Nissenbaum, Etgar; Alexis, Frank; Lupták, Andrej; Teply, Benjamin A.; Chan, Juliana M.; Shi, Jinjun; Digga, Elise; Cheng, Judy; Langer, Robert; Farokhzad, Omid C.

    2012-01-01

    One of the major challenges in the development of targeted nanoparticles (NPs) for cancer therapy is to discover targeting ligands that allow for differential binding and uptake by the target cancer cells. Using prostate cancer (PCa) as a model disease, we developed a cell-uptake selection strategy to isolate PCa-specific internalizing 2'-Omethyl RNA aptamers (Apts) for NP incorporation. Twelve cycles of selection and counter-selection were done to obtain a panel of internalizing Apts, which can distinguish PCa cells from non-prostate and normal prostate cells. After Apt characterization, size minimization, and conjugation of the Apts with fluorescently-labeled polymeric NPs, the NP-Apt bioconjugates exhibit PCa specificity and enhancement in cellular uptake when compared to non-targeted NPs lacking the internalizing Apts. Furthermore, when docetaxel, a chemotherapeutic agent used for the treatment of PCa, was encapsulated within the NP-Apt, a significant improvement in cytotoxicity was achieved in targeted PCa cells. Rather than isolating high-affinity Apts as reported in previous selection processes, our selection strategy was designed to enrich cancer-cell specific internalizing Apts. A similar cell-uptake selection strategy may be used to develop specific internalizing ligands for a myriad of other diseases and can potentially facilitate delivering various molecules, including drugs and siRNAs, into cells. PMID:22214176

  20. DNA repair after ultraviolet irradiation of ICR 2A frog cells: pyrimidine dimers are long acting blocks to nascent DNA synthesis

    International Nuclear Information System (INIS)

    The ability of ICR 2A frog cells to repair DNA damage induced by ultraviolet irradiation was examined. These cells are capable of photoreactivation but are nearly totally deficient in excision repair. They have the ability to convert the small molecular weight DNA made after irradiation into large molecules but do not show an enhancement in this process when the UV dose is delivered in two separate exposures separated by a 3- or 24-h incubation. Total DNA synthesis is depressed and low molecular weight DNA continues to be synthesized during pulse-labeling as long as 48 h after irradiation. The effects of pyrimidine dimer removal through exposure of UV irradiated cells to photoreactivating light indicate that dimers act as the critical lesions blocking DNA synthesis

  1. Large Block Test Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Lin, W

    2001-12-01

    . Sections 5 through 9 report the measurements made on the block during the preheating, heating, and cooling phases. These measurements include temperature, thermal conductivity and diffusivity, hydrological measurements (electrical resistivity, neutron logging, gas pressure, and relative humidity), geomechanics, selected chemical analyses, and microbial activity. These sections also include analyses and simulations of the block behavior. Finally, conclusions are presented in Section 10. Complete data sets were submitted during the time the test was conducted. The data tracking numbers (DTNs) of all of the data are presented in Table 1-1.

  2. Prediction of cell-penetrating peptides with feature selection techniques.

    Science.gov (United States)

    Tang, Hua; Su, Zhen-Dong; Wei, Huan-Huan; Chen, Wei; Lin, Hao

    2016-08-12

    Cell-penetrating peptides are a group of peptides which can transport different types of cargo molecules such as drugs across plasma membrane and have been applied in the treatment of various diseases. Thus, the accurate prediction of cell-penetrating peptides with bioinformatics methods will accelerate the development of drug delivery systems. The study aims to develop a powerful model to accurately identify cell-penetrating peptides. At first, the peptides were translated into a set of vectors with the same dimension by using dipeptide compositions. Secondly, the Analysis of Variance-based technique was used to reduce the dimension of the vector and explore the optimized features. Finally, the support vector machine was utilized to discriminate cell-penetrating peptides from non-cell-penetrating peptides. The five-fold cross-validated results showed that our proposed method could achieve an overall prediction accuracy of 83.6%. Based on the proposed model, we constructed a free webserver called C2Pred (http://lin.uestc.edu.cn/server/C2Pred). PMID:27291150

  3. Selection of optimal sensors for predicting performance of polymer electrolyte membrane fuel cell

    Science.gov (United States)

    Mao, Lei; Jackson, Lisa

    2016-10-01

    In this paper, sensor selection algorithms are investigated based on a sensitivity analysis, and the capability of optimal sensors in predicting PEM fuel cell performance is also studied using test data. The fuel cell model is developed for generating the sensitivity matrix relating sensor measurements and fuel cell health parameters. From the sensitivity matrix, two sensor selection approaches, including the largest gap method, and exhaustive brute force searching technique, are applied to find the optimal sensors providing reliable predictions. Based on the results, a sensor selection approach considering both sensor sensitivity and noise resistance is proposed to find the optimal sensor set with minimum size. Furthermore, the performance of the optimal sensor set is studied to predict fuel cell performance using test data from a PEM fuel cell system. Results demonstrate that with optimal sensors, the performance of PEM fuel cell can be predicted with good quality.

  4. Peripheral opioid antagonist enhances the effect of anti-tumor drug by blocking a cell growth-suppressive pathway in vivo.

    Directory of Open Access Journals (Sweden)

    Masami Suzuki

    Full Text Available The dormancy of tumor cells is a major problem in chemotherapy, since it limits the therapeutic efficacy of anti-tumor drugs that only target dividing cells. One potential way to overcome chemo-resistance is to "wake up" these dormant cells. Here we show that the opioid antagonist methylnaltrexone (MNTX enhances the effect of docetaxel (Doc by blocking a cell growth-suppressive pathway. We found that PENK, which encodes opioid growth factor (OGF and suppresses cell growth, is predominantly expressed in diffuse-type gastric cancers (GCs. The blockade of OGF signaling by MNTX releases cells from their arrest and boosts the effect of Doc. In comparison with the use of Doc alone, the combined use of Doc and MNTX significantly prolongs survival, alleviates abdominal pain, and diminishes Doc-resistant spheroids on the peritoneal membrane in model mice. These results suggest that blockade of the pathways that suppress cell growth may enhance the effects of anti-tumor drugs.

  5. The virion host shut-off (vhs protein blocks a TLR-independent pathway of herpes simplex virus type 1 recognition in human and mouse dendritic cells.

    Directory of Open Access Journals (Sweden)

    Christopher R Cotter

    Full Text Available Molecular pathways underlying the activation of dendritic cells (DCs in response to Herpes Simplex Virus type 1 (HSV-1 are poorly understood. Removal of the HSV virion host shut-off (vhs protein relieves a block to DC activation observed during wild-type infection. In this study, we utilized a potent DC stimulatory HSV-1 recombinant virus lacking vhs as a tool to investigate the mechanisms involved in the activation of DCs by HSV-1. We report that the release of pro-inflammatory cytokines by conventional DC (cDC during HSV-1 infection is triggered by both virus replication-dependent and replication-independent pathways. Interestingly, while vhs is capable of inhibiting the release of cytokines during infection of human and mouse cDCs, the secretion of cytokines by plasmacytoid DC (pDC is not affected by vhs. These data prompted us to postulate that infection of cDCs by HSV triggers a TLR independent pathway for cDC activation that is susceptible to blockage by the vhs protein. Using cDCs isolated from mice deficient in both the TLR adaptor protein MyD88 and TLR3, we show that HSV-1 and the vhs-deleted virus can activate cDCs independently of TLR signaling. In addition, virion-associated vhs fails to block cDC activation in response to treatment with TLR agonists, but it efficiently blocked cDC activation triggered by the paramyxoviruses Sendai Virus (SeV and Newcastle Disease Virus (NDV. This block to SeV- and NDV-induced activation of cDC resulted in elevated SeV and NDV viral gene expression indicating that infection with HSV-1 enhances the cell's susceptibility to other pathogens through the action of vhs. Our results demonstrate for the first time that a viral protein contained in the tegument of HSV-1 can block the induction of DC activation by TLR-independent pathways of viral recognition.

  6. 2-Methoxy-4-vinylphenol can induce cell cycle arrest by blocking the hyper-phosphorylation of retinoblastoma protein in benzo[a]pyrene-treated NIH3T3 cells

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Jin Boo [Bioresource Sciences, Andong National University, Andong 760749 (Korea, Republic of); Jeong, Hyung Jin, E-mail: jhj@andong.ac.kr [Bioresource Sciences, Andong National University, Andong 760749 (Korea, Republic of)

    2010-10-01

    Research highlights: {yields} 2M4VP activated the expression of p21 and p15 protein, and down-regulated the expression of cyclin D1 and cyclin E. {yields} 2M4VP inhibited hyper-phosphorylation of Rb protein. {yields} 2M4VP induced cell cycle arrest from G1 to S. {yields} 2M4VP inhibited hyper-proliferation of the cells in BaP-treated cells. {yields} 2M4VP induces growth arrest of BaP-treated cells by blocking hyper-phosphorylation of Rb via regulating the expression of cell cycle-related proteins. -- Abstract: Benzo[a]pyrene (BaP) is an environment carcinogen that can enhance cell proliferation by disturbing the signal transduction pathways in cell cycle regulation. In this study, the effects of 2M4VP on cell proliferation, cell cycle and cell cycle regulatory proteins were studied in BaP-treated NIH 3T3 cells to establish the molecular mechanisms of 2M4VP as anti-proliferative agents. 2M4VP exerted a dose-dependent inhibitory effect on cell growth correlated with a G1 arrest. Analysis of G1 cell cycle regulators expression revealed 2M4VP increased expression of CDK inhibitor, p21Waf1/Cip1 and p15 INK4b, decreased expression of cyclin D1 and cyclin E, and inhibited kinase activities of CDK4 and CDK2. However, 2M4VP did not affect the expression of CDK4 and CDK2. Also, 2M4VP inhibited the hyper-phosphorylation of Rb induced by BaP. Our results suggest that 2M4VP induce growth arrest of BaP-treated NIH 3T3 cells by blocking the hyper-phosphorylation of Rb via regulating the expression of cell cycle-related proteins.

  7. A novel potent Fas agonist for selective depletion of tumor cells in hematopoietic transplants

    OpenAIRE

    Nahimana, A; AUBRY, D.; Lagopoulos, L; Greaney, P.; Attinger, A; Demotz, S; Dawson, K. M.; Schapira, M; Tschopp, J; Dupuis, M.; Duchosal, M A

    2011-01-01

    There remains a clear need for effective tumor cell purging in autologous stem cell transplantation (ASCT) where residual malignant cells within the autograft contribute to disease relapse. Here we propose the use of a novel Fas agonist with potent pro-apoptotic activity, termed MegaFasL, as an effective ex-vivo purging agent. MegaFasL selectively kills hematological cancer cells from lymphomas and leukemias and prevents tumor development at concentrations that do not reduce the functional ca...

  8. Selective tropism of liver stem cells to hepatocellular carcinoma in vivo

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    AIM: To investigate the selective tropism of liver stem cells to hepatocellular carcinoma (HCC) in an animal model and its feasibility as a vector to deliver therapeutic genes for targeted therapy of HCC.METHODS: WB-F344, a kind of rat liver stem cell,was infected with recombinant virus to establish a cell line with stable, high-level expressing enhanced green fluorescent protein (EGFP). An animal model of HCC in Wistar rats was established by implanting HCC cells (CBRH7919) combined with an immunosuppressive drug.EGFP labeled liver stem cells were injected into caudal veins of the animals and distribution was observed at different time points after injection. SDF-1 and c-kit expression in non-tumor liver and tumor tissue were analysed by immunohistochemistry for the relationshiop between the expression and migration of liver stem cells.Furthermore, hepatic stem cells were injected via the portal vein, hepatic artery, caudal vein, or directly into the pericancerous liver tissue, respectively, and effects on migration, localization, and proliferation of the hepatic stem cells within the tumor tissue were observed and analyzed.RESULTS: Recombinant adenovirus could deliver the EGFP gene to hepatic stem cells. A new stem cell line,named WB-EGFP, was established that stably expressed EGFP. WB-EGFP cells still showed selective tropism towards HCC and EGFP expression was stable in vivo.According to immunohistochemistry results, SDF-1 may not be related to the mechanisms of tropism of hepatic stem cells. Different application sites affected the distribution of liver stem cells. Injection via the portal vein was superior with regard to selective migration,localization, and proliferation of the hepatic stem cells within the tumor tissue.CONCLUSION: Liver stem cells have the biological behavior of selective migration to HCC in vivo and they could localize and proliferate within HCC tissue stably expressing the target gene. Liver stem cells are a potential tool for a targeted

  9. Piperlongumine selectively kills cancer cells and increases cisplatin antitumor activity in head and neck cancer

    OpenAIRE

    Roh, Jong-Lyel; Kim, Eun Hye; Park, Jin Young; Kim, Ji Won; Kwon, Minsu; Lee, Byung-Heon

    2014-01-01

    Adaptation to cellular stress is not a vital function of normal cells but is required of cancer cells, and as such might be a sensible target in cancer therapy. Piperlongumine is a naturally occurring small molecule selectively toxic to cancer cells. This study assesses the cytotoxicity of piperlongumine and its combination with cisplatin in head-and-neck cancer (HNC) cells in vitro and in vivo. The effect of piperlongumine, alone and in combination with cisplatin, was assessed in human HNC c...

  10. Selective differentiation and proliferation of hematopoietic cells induced by recombinant human interleukins.

    OpenAIRE

    Saito, H; Hatake, K.; Dvorak, A. M.; Leiferman, K M; Donnenberg, A D; Arai, N.; Ishizaka, K; Ishizaka, T

    1988-01-01

    Effects of recombinant human interleukins on hematopoiesis were explored by using suspension cultures of mononuclear cells of human umbilical-cord blood and bone marrow. The results showed that interleukin 5 induced the selective differentiation and proliferation of eosinophils. After 3 weeks in culture with interleukin 5, essentially all nonadherent cells in both bone marrow and cord blood cell cultures became eosinophilic myelocytes. Culture of the same cells with interleukin 4 resulted in ...

  11. Cancer stem-like cells can be isolated with drug selection in human ovarian cancer cell line SKOV3

    Institute of Scientific and Technical Information of China (English)

    Li Ma; Dongmei Lai; Te Liu; Weiwei Cheng; Lihe Guo

    2010-01-01

     One emerging model for the development of drugresistant tumors utilizes a pool of self-renewing malignant progenitors known as cancer stem cells(CSCs)or cancerinitiating cells(CICs).The purpose of this study was to propagate such CICs from the ovarian cancer cell line SKOV3.The SKOV3 sphere cells were selected using 40.0 μmol/l cisplatin and 10.0 μmol/l paclitaxel in serumfree culture system supplemented with epidermal growth factor,basic fibroblast growth factor,leukemia inhibitory factor,and insufin or standard serum-containing system.These cells formed non-adherent spheres under drug selection(cisplatin and paclitaxel)and serum-free culture system.The selected sphere cells are more resistant to cisplatin,paclitaxel,adriamycin,and methotrexate.Importantly,the sphere cells have the properties of se lfrenewal,with high expression of the stem cell genes Nanog,Oct4,sox2,nestin,ABCG2,CD133,and the stem cell factor receptor CD117(c-kit).Consistently,flow cytometric analysis revealed that the sphere cells have a much higher percentage of CD133+/CD117+-positive cells (71%)than differentiated cells(33%).Moreover,the SKOV3 sphere cells are more tumorigenic.Furthermore,cDNA microarray and subsequent ontological analyses revealed that a large proportion of the classified genes were related to angiogenesis,extracellular matrix,integrin-mediated signaling pathway,cell adhesion,and cell proliferation.The subpopulation isolation from the SKOV3 cell line under this culture system offers a suitable in vitro model for studying ovarian CSCs in terms of their survival,self-renewal,and chemoresistance,and for developing therapeutic drugs that specifically interfere with ovarian CSCs.

  12. Copper conducting electrode with nickel as a seed layer for selective emitter crystalline silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Rehman, Atteq ur; Shin, Eun Gu; Lee, Soo Hong [Sejong University, Seoul (Korea, Republic of)

    2014-09-15

    In this research, we investigated selective emitter formation with a single-step photolithography process having a metallization scheme composed of nickel/copper metal stacks. The nickel seed layers were deposited by applying the electroless deposition process while copper was formed by light induced electro-plating arrangements as the main conducting electrode. The electroless deposition of nickel, along with a sintering process, was employed to create a diffusion barrier between copper and silicon. The nickel metal stack below the copper-conducting electrode also helped in lowering the sheet resistance and improving the contact adhesion. The nickel used as a seed layer was successfully demonstrated in the fabrication of a homogeneous 60 Ω/ emitter and selective emitter cells. Lower series resistances of 0.165 Ω and 0.253 Ω were achieved for the selective emitter and the homogeneous emitter cells, respectively. The best cell efficiency of 18.37% for the selective emitter solar cell was achieved, with average cell efficiencies of 18.17% and 17.3% for the selective emitter and the homogeneous emitter cells, respectively. An approximate efficiency increase of about 0.8% was recorded for the selective emitter solar cells.

  13. Glimpse of natural selection of long-lived T-cell clones in healthy life.

    Science.gov (United States)

    Zhang, Baojun; Jia, Qingzhu; Bock, Cheryl; Chen, Gang; Yu, Haili; Ni, Qingshan; Wan, Ying; Li, Qijing; Zhuang, Yuan

    2016-08-30

    Homeostatic maintenance of T cells with broad clonal diversity is influenced by both continuing output of young T cells from the thymus and ongoing turnover of preexisting clones in the periphery. In the absence of infection, self and commensal antigens are thought to play important roles in selection and homeostatic maintenance of the T-cell pool. Most naïve T cells are short-lived due to lack of antigen encounter, whereas antigen-experienced T cells may survive and persist as long-lived clones. Thus far, little is known about the homeostasis, antigenic specificity, and clonal diversity of long-lived T-cell clones in peripheral lymphoid organs under healthy living conditions. To identify long-lived T-cell clones in mice, we designed a lineage-tracing method to label a wave of T cells produced in the thymus of young mice. After aging the mice for 1.5 y, we found that lineage-tracked T cells consisted of primarily memory-like T cells and T regulatory cells. T-cell receptor repertoire analysis revealed that the lineage-tracked CD4 memory-like T cells and T regulatory cells exhibited age-dependent enrichment of shared clonotypes. Furthermore, these shared clonotypes were found across different mice maintained in the same housing condition. These findings suggest that nonrandom and shared antigens are involved in controlling selection, retention, and immune tolerance of long-lived T-cell clones under healthy living conditions. PMID:27535935

  14. Multifunctionalized iron oxide nanoparticles for selective drug delivery to CD44-positive cancer cells

    Science.gov (United States)

    Aires, Antonio; Ocampo, Sandra M.; Simões, Bruno M.; Josefa Rodríguez, María; Cadenas, Jael F.; Couleaud, Pierre; Spence, Katherine; Latorre, Alfonso; Miranda, Rodolfo; Somoza, Álvaro; Clarke, Robert B.; Carrascosa, José L.; Cortajarena, Aitziber L.

    2016-02-01

    Nanomedicine nowadays offers novel solutions in cancer therapy and diagnosis by introducing multimodal treatments and imaging tools in one single formulation. Nanoparticles acting as nanocarriers change the solubility, biodistribution and efficiency of therapeutic molecules, reducing their side effects. In order to successfully apply these novel therapeutic approaches, efforts are focused on the biological functionalization of the nanoparticles to improve the selectivity towards cancer cells. In this work, we present the synthesis and characterization of novel multifunctionalized iron oxide magnetic nanoparticles (MNPs) with antiCD44 antibody and gemcitabine derivatives, and their application for the selective treatment of CD44-positive cancer cells. The lymphocyte homing receptor CD44 is overexpressed in a large variety of cancer cells, but also in cancer stem cells (CSCs) and circulating tumor cells (CTCs). Therefore, targeting CD44-overexpressing cells is a challenging and promising anticancer strategy. Firstly, we demonstrate the targeting of antiCD44 functionalized MNPs to different CD44-positive cancer cell lines using a CD44-negative non-tumorigenic cell line as a control, and verify the specificity by ultrastructural characterization and downregulation of CD44 expression. Finally, we show the selective drug delivery potential of the MNPs by the killing of CD44-positive cancer cells using a CD44-negative non-tumorigenic cell line as a control. In conclusion, the proposed multifunctionalized MNPs represent an excellent biocompatible nanoplatform for selective CD44-positive cancer therapy in vitro.

  15. Selective killing of methotrexate-resistant cells carrying amplified dihydrofolate reductase genes

    International Nuclear Information System (INIS)

    A method for the selective killing of methotrexate (MTX)-resistant cells has been developed. The selection is based on the incorporation of tritiated deoxyuridine into the DNA of MTX-resistant cells but not normal MTX-sensitive cells in the presence of the drug. A Chinese hamster ovary cell mutant that overproduces dihydrofolate reductase was used as an example of a MTX-resistant cell line. In this system, a 10,000-fold enrichment for wild-type MTX-sensitive cells could be achieved after 24 hr of exposure to the drug combination. This selection technique was applied to the isolation of MTX-sensitive segregants from hybrid cells formed between the MTX-resistant mutant and wild-type cells. The loss of MTX resistance and dihydrofolate reductase overproduction was always accompanied by the loss of a homogeneously staining region on chromosome 2 of the resistant parent that contains the amplified genes specifying this enzyme. While this region is always lost, other parts of chromosome 2 are almost always retained, suggesting that deletion rather than chromosome loss underlies marker segregation in this case. When the selection was applied to the resistant mutant itself, no MTX-sensitive revertants were obtained among 10(5) cells screened, attesting to the stability of gene amplification in this clone. It is suggested that this combination of drugs may be useful for the elimination of MTX-resistant tumor cells that develop after MTX chemotherapy

  16. Immunohistochemical detection of estrogen receptor, progesterone receptor and human epidermal growth factor receptor 2 in formalin-fixed breast carcinoma cell block preparations: correlation of results to corresponding tissue block (needle core and excision) samples.

    Science.gov (United States)

    Kinsella, Mary D; Birdsong, George G; Siddiqui, Momin T; Cohen, Cynthia; Hanley, Krisztina Z

    2013-03-01

    Evaluation of ER, PR and Her 2 are routinely performed on breast carcinomas. For accurate detection of these markers, compliance with the ASCO/CAP guidelines is recommended. Our previous study showed that alcohol fixation did not affect ER results when alcohol-fixed cell block (CB) sections were compared to formalin-fixed tissue sections, while PR and Her2 showed less concordance. The aim of this study was to evaluate and to compare ER, PR and Her2 IHC results on formalin-fixed CB sections to those observed on subsequent surgical (needle core or resection) specimens (SS). Fifty cases of formalin fixed CB samples obtained from primary (18%) and metastatic (82%) breast carcinomas were studied, all of which had subsequent SS available. ER, PR, and Her2 IHC studies were done on all samples and results were compared. ER results on formalin-fixed CB samples showed excellent correlation with SS (correlation coefficient cc = 0.82). While there was minimal improvement in PR results (cc = 0.433), Her2 detection did not improve by formalin fixation (cc = 0.439). Formalin fixation for CB preparations does not significantly improve the already good detection of ER positive breast tumors. The concordance rate in PR and IHC results between formalin-fixed CB and SS samples showed improvement as compared with the alcohol-fixed CB results. However, there was no improvement in detection of Her2 overexpression by using formalin fixation on cytology specimens.

  17. New method for selection of hydrogen peroxide adapted bifidobacteria cells using continuous culture and immobilized cell technology

    Directory of Open Access Journals (Sweden)

    Meile Leo

    2010-07-01

    Full Text Available Abstract Background Oxidative stress can severely compromise viability of bifidobacteria. Exposure of Bifidobacterium cells to oxygen causes accumulation of reactive oxygen species, mainly hydrogen peroxide, leading to cell death. In this study, we tested the suitability of continuous culture under increasing selective pressure combined with immobilized cell technology for the selection of hydrogen peroxide adapted Bifidobacterium cells. Cells of B. longum NCC2705 were immobilized in gellan-xanthan gum gel beads and used to continuously ferment MRS medium containing increasing concentration of H2O2 from 0 to 130 ppm. Results At the beginning of the culture, high cell density of 1013 CFU per litre of reactor was tested. The continuous culture gradually adapted to increasing H2O2 concentrations. However, after increasing the H2O2 concentration to 130 ppm the OD of the culture decreased to 0. Full wash out was prevented by the immobilization of the cells in gel matrix. Hence after stopping the stress, it was possible to re-grow the cells that survived the highest lethal dose of H2O2 and to select two adapted colonies (HPR1 and HPR2 after plating of the culture effluent. In contrast to HPR1, HPR2 showed stable characteristics over at least 70 generations and exhibited also higher tolerance to O2 than non adapted wild type cells. Preliminary characterization of HPR2 was carried out by global genome expression profile analysis. Two genes coding for a protein with unknown function and possessing trans-membrane domains and an ABC-type transporter protein were overexpressed in HPR2 cells compared to wild type cells. Conclusions Our study showed that continuous culture with cell immobilization is a valid approach for selecting cells adapted to hydrogen peroxide. Elucidation of H2O2 adaptation mechanisms in HPR2 could be helpful to develop oxygen resistant bifidobacteria.

  18. Selective COX-2 inhibitor, NS-398, suppresses cellular proliferation in human hepatocellular carcinoma cell lines via cell cycle arrest

    Institute of Scientific and Technical Information of China (English)

    Ji Yeon Baek; Wonhee Hur; Jin Sang Wang; Si Hyun Bae; Seung Kew Yoon

    2007-01-01

    AIM: To investigate the growth inhibitory mechanism of NS-398, a selective cyclooxygenase-2 (COX-2) inhibitor,in two hepatocellular carcinoma (HCC) cell lines (HepG2and Huh7).METHODS: HepG2 and Huh7 cells were treated with NS-398. Its effects on cell viability, cell proliferation,cell cycles, and gene expression were respectively evaluated by water-soluble tetrazolium salt (WST-1)assay, 4'-6-diamidino-2-phenylindole (DAPI) staining,flow cytometer analysis, and Western blotting,with dimethyl sulfoxide (DMSO) as positive control.RESULTS: NS-398 showed dose- and time-dependent growth-inhibitory effects on the two cell lines.Proliferating cell nuclear antigen (PCNA) expressions in HepG2 and Huh7 cells, particularly in Huh7 cells were inhibited in a time- and dose-independent manner.NS-398 caused cell cycle arrest in the G1 phase with cell accumulation in the sub-G1 phase in HepG2 and Huh7cell lines. No evidence of apoptosis was observed in two cell lines.CONCLUSION: NS-398 reduces cell proliferation by inducing cell cycle arrest in HepG2 and Huh7 cell lines,and COX-2 inhibitors may have potent chemoprevention effects on human hepatocellular carcinoma.

  19. Energy deposition in selected-mammalian cell for several-MeV single-proton beam

    Science.gov (United States)

    Ding, K.; Yu, Z.

    2007-05-01

    The phenomena resulting from interaction between ion beam and mammalian cell pose important problems for biological applications. Classic Bethe-Bloch theory utilizing attached V79 mammalian cell has been conducted in order to establish the stopping powers of the mammalian cell for several-MeV single-proton microbeam. Based on the biological structure of the mammalian cell, a physical model is proposed which presumes that the attached cell is simple MWM model. According to this model and Monte Carlo simulation, we studied the energy deposition and its ratio on the selected attached mammalian cell for MeV proton implantation.

  20. Myeloblastic leukemia cells conditionally blocked by myc-estrogen receptor chimeric transgenes for terminal differentiation coupled to growth arrest and apoptosis.

    Science.gov (United States)

    Selvakumaran, M; Liebermann, D; Hoffman-Liebermann, B

    1993-05-01

    Conditional mutants of the myeloblastic leukemic M1 cell line, expressing the chimeric mycer transgene, have been established. It is shown that M1 mycer cells, like M1, undergo terminal differentiation coupled to growth arrest and programmed cell death (apoptosis) after treatment with the physiologic differentiation inducer interleukin-6. However, when beta-estradiol is included in the culture medium, M1 mycer cells respond to differentiation inducers like M1 myc cell lines, where the differentiation program is blocked at an intermediate stage. By manipulating the function of the mycer transgene product, it is shown that there is a 10-hour window during myeloid differentiation, from 30 to 40 hours after the addition of the differentiation inducer, when the terminal differentiation program switches from being dependent on c-myc suppression to becoming c-myc suppression independent, where activation of c-myc has no apparent effect on mature macrophages. M1 mycer cell lines provide a powerful tool to increase our understanding of the role of c-myc in normal myelopoiesis and in leukemogenesis, also providing a strategy to clone c-myc target genes.

  1. Kaposi sarcoma herpes virus latency associated nuclear antigen protein release the G2/M cell cycle blocks by modulating ATM/ATR mediated checkpoint pathway.

    Directory of Open Access Journals (Sweden)

    Amit Kumar

    Full Text Available The Kaposi's sarcoma-associated herpesvirus infects the human population and maintains latency stage of viral life cycle in a variety of cell types including cells of epithelial, mesenchymal and endothelial origin. The establishment of latent infection by KSHV requires the expression of an unique repertoire of genes among which latency associated nuclear antigen (LANA plays a critical role in the replication of the viral genome. LANA regulates the transcription of a number of viral and cellular genes essential for the survival of the virus in the host cell. The present study demonstrates the disruption of the host G2/M cell cycle checkpoint regulation as an associated function of LANA. DNA profile of LANA expressing human B-cells demonstrated the ability of this nuclear antigen in relieving the drug (Nocodazole induced G2/M checkpoint arrest. Caffeine suppressed nocodazole induced G2/M arrest indicating involvement of the ATM/ATR. Notably, we have also shown the direct interaction of LANA with Chk2, the ATM/ATR signalling effector and is responsible for the release of the G2/M cell cycle block.

  2. The endocannabinoid N-arachidonoyl dopamine (NADA) selectively induces oxidative stress-mediated cell death in hepatic stellate cells but not in hepatocytes.

    Science.gov (United States)

    Wojtalla, Alexandra; Herweck, Frank; Granzow, Michaela; Klein, Sabine; Trebicka, Jonel; Huss, Sebastian; Lerner, Raissa; Lutz, Beat; Schildberg, Frank Alexander; Knolle, Percy Alexander; Sauerbruch, Tilman; Singer, Manfred Vincenz; Zimmer, Andreas; Siegmund, Sören Volker

    2012-04-15

    The endocannabinoid system is a crucial regulator of hepatic fibrogenesis. We have previously shown that the endocannabinoid anandamide (AEA) is a lipid mediator that blocks proliferation and induces death in hepatic stellate cells (HSCs), the main fibrogenic cell type in the liver, but not in hepatocytes. However, the effects of other endocannabinoids such as N-arachidonoyl dopamine (NADA) have not yet been investigated. The NADA-synthesizing enzyme tyrosine hydroxylase was mainly expressed in sympathetic neurons in portal tracts. Its expression pattern stayed unchanged in normal or fibrotic liver. NADA dose dependently induced cell death in culture-activated primary murine or human HSCs after 2-4 h, starting from 5 μM. Despite caspase 3 cleavage, NADA-mediated cell death showed typical features of necrosis, including ATP depletion. Although the cannabinoid receptors CB1, CB2, or transient receptor potential cation channel subfamily V, member 1 were expressed in HSCs, their pharmacological or genetic blockade failed to inhibit NADA-mediated death, indicating a cannabinoid-receptor-independent mechanism. Interestingly, membrane cholesterol depletion with methyl-β-cyclodextrin inhibited AEA- but not NADA-induced death. NADA significantly induced reactive oxygen species formation in HSCs. The antioxidant glutathione (GSH) significantly decreased NADA-induced cell death. Similar to AEA, primary hepatocytes were highly resistant against NADA-induced death. Resistance to NADA in hepatocytes was due to high levels of GSH, since GSH depletion significantly increased NADA-induced death. Moreover, high expression of the AEA-degrading enzyme fatty acid amide hydrolase (FAAH) in hepatocytes also conferred resistance towards NADA-induced death, since pharmacological or genetic FAAH inhibition significantly augmented hepatocyte death. Thus the selective induction of cell death in HSCs proposes NADA as a novel antifibrogenic mediator.

  3. Selective Cancer Targeting via Aberrant Behavior of Cancer Cell-associated Glucocorticoid Receptor

    OpenAIRE

    Mukherjee, Amarnath; Narayan, Kumar P; Pal, Krishnendu; Kumar, Jerald M.; Rangaraj, Nandini; Shasi V Kalivendi; Banerjee, Rajkumar

    2009-01-01

    Glucocorticoid receptors (GRs) are ubiquitous, nuclear hormone receptors residing in cell types of both cancer and noncancerous origin. It is not known whether cancer cell–associated GR alone can be selectively manipulated for delivery of exogenous genes to its nucleus for eliciting anticancer effect. We find that GR ligand, dexamethasone (Dex) in association with cationic lipoplex (termed as targeted lipoplex) could selectively manipulate GR in cancer cells alone for the delivery of transgen...

  4. Combinational Effect of Cell Adhesion Biomolecules and Their Immobilized Polymer Property to Enhance Cell-Selective Adhesion

    Directory of Open Access Journals (Sweden)

    Rio Kurimoto

    2016-01-01

    Full Text Available Although surface immobilization of medical devices with bioactive molecules is one of the most widely used strategies to improve biocompatibility, the physicochemical properties of the biomaterials significantly impact the activity of the immobilized molecules. Herein we investigate the combinational effects of cell-selective biomolecules and the hydrophobicity/hydrophilicity of the polymeric substrate on selective adhesion of endothelial cells (ECs, fibroblasts (FBs, and smooth muscle cells (SMCs. To control the polymeric substrate, biomolecules are immobilized on thermoresponsive poly(N-isopropylacrylamide-co-2-carboxyisopropylacrylamide (poly(NIPAAm-co-CIPAAm-grafted glass surfaces. By switching the molecular conformation of the biomolecule-immobilized polymers, the cell-selective adhesion performances are evaluated. In case of RGDS (Arg-Gly-Asp-Ser peptide-immobilized surfaces, all cell types adhere well regardless of the surface hydrophobicity. On the other hand, a tri-Arg-immobilized surface exhibits FB-selectivity when the surface is hydrophilic. Additionally, a tri-Ile-immobilized surface exhibits EC-selective cell adhesion when the surface is hydrophobic. We believe that the proposed concept, which is used to investigate the biomolecule-immobilized surface combination, is important to produce new biomaterials, which are highly demanded for medical implants and tissue engineering.

  5. Enhanced transfection of cell lines from Atlantic salmon through nucoleofection and antibiotic selection

    Directory of Open Access Journals (Sweden)

    Mjaaland Siri

    2011-05-01

    Full Text Available Abstract Background Cell lines from Atlantic salmon kidney have made it possible to culture and study infectious salmon anemia virus (ISAV, an aquatic orthomyxovirus affecting farmed Atlantic salmon. However, transfection of these cells using calcium phosphate precipitation or lipid-based reagents shows very low transfection efficiency. The Amaxa Nucleofector technology™ is an electroporation technique that has been shown to be efficient for gene transfer into primary cells and hard to transfect cell lines. Findings Here we demonstrate, enhanced transfection of the head kidney cell line, TO, from Atlantic salmon using nucleofection and subsequent flow cytometry. Depending on the plasmid promoter, TO cells could be transfected transiently with an efficiency ranging from 11.6% to 90.8% with good viability, using Amaxa's cell line nucleofector solution T and program T-20. A kill curve was performed to investigate the most potent antibiotic for selection of transformed cells, and we found that blasticidin and puromycin were the most efficient for selection of TO cells. Conclusions The results show that nucleofection is an efficient way of gene transfer into Atlantic salmon cells and that stably transfected cells can be selected with blasticidin or puromycin.

  6. Benzothiophene inhibitors of MK2. Part 2: improvements in kinase selectivity and cell potency.

    Science.gov (United States)

    Anderson, David R; Meyers, Marvin J; Kurumbail, Ravi G; Caspers, Nicole; Poda, Gennadiy I; Long, Scott A; Pierce, Betsy S; Mahoney, Matthew W; Mourey, Robert J; Parikh, Mihir D

    2009-08-15

    Optimization of kinase selectivity for a set of benzothiophene MK2 inhibitors provided analogs with potencies of less than 500 nM in a cell based assay. The selectivity of the inhibitors can be rationalized by examination of X-ray crystal structures of inhibitors bound to MK2.

  7. Benzothiophene inhibitors of MK2. Part 2: Improvements in kinase selectivity and cell potency

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, David R.; Meyers, Marvin J.; Kurumbail, Ravi G.; Caspers, Nicole; Poda, Gennadiy I.; Long, Scott A.; Pierce, Betsy S.; Mahoney, Matthew W.; Mourey, Robert J.; Parikh, Mihir D.; Pfizer

    2010-10-01

    Optimization of kinase selectivity for a set of benzothiophene MK2 inhibitors provided analogs with potencies of less than 500 nM in a cell based assay. The selectivity of the inhibitors can be rationalized by examination of X-ray crystal structures of inhibitors bound to MK2.

  8. Beyond Helper Phage: Using "Helper Cells" to Select Peptide Affinity Ligands.

    Science.gov (United States)

    Phipps, M Lisa; Lillo, Antoinetta M; Shou, Yulin; Schmidt, Emily N; Paavola, Chad D; Naranjo, Leslie; Bemdich, Sara; Swanson, Basil I; Bradbury, Andrew R M; Martinez, Jennifer S

    2016-01-01

    Peptides are important affinity ligands for microscopy, biosensing, and targeted delivery. However, because they can have low affinity for their targets, their selection from large naïve libraries can be challenging. When selecting peptidic ligands from display libraries, it is important to: 1) ensure efficient display; 2) maximize the ability to select high affinity ligands; and 3) minimize the effect of the display context on binding. The "helper cell" packaging system has been described as a tool to produce filamentous phage particles based on phagemid constructs with varying display levels, while remaining free of helper phage contamination. Here we report on the first use of this system for peptide display, including the systematic characterization and optimization of helper cells, their inefficient use in antibody display and their use in creating and selecting from a set of phage display peptide libraries. Our libraries were analyzed with unprecedented precision by standard or deep sequencing, and shown to be superior in quality than commercial gold standards. Using our helper cell libraries, we have obtained ligands recognizing Yersinia pestis surface antigen F1V and L-glutamine-binding periplasmic protein QBP. In the latter case, unlike any of the peptide library selections described so far, we used a combination of phage and yeast display to select intriguing peptide ligands. Based on the success of our selections we believe that peptide libraries obtained with helper cells are not only suitable, but preferable to traditional phage display libraries for selection of peptidic ligands. PMID:27626637

  9. Impact of selection for decreased somatic cell score on productive life and culling for mastitis

    Science.gov (United States)

    Impact of continued selection for decreased somatic cell score (SCS) was examined to determine if such selection resulted in greater mastitis susceptibility and shorter productive life (PL). Holstein artificial-insemination bulls with a predicted transmitting ability (PTA) for SCS based on >=35 daug...

  10. Distinct genetic alterations occur in ovarian tumor cells selected for combined resistance to carboplatin and docetaxel

    Directory of Open Access Journals (Sweden)

    Armstrong Stephen R

    2012-11-01

    Full Text Available Abstract Background Current protocols for the treatment of ovarian cancer include combination chemotherapy with a platinating agent and a taxane. However, many patients experience relapse of their cancer and the development of drug resistance is not uncommon, making successful second line therapy difficult to achieve. The objective of this study was to develop and characterize a cell line resistant to both carboplatin and docetaxel (dual drug resistant ovarian cell line and to compare this cell line to cells resistant to either carboplatin or docetaxel. Methods The A2780 epithelial endometrioid ovarian cancer cell line was used to select for isogenic carboplatin, docetaxel and dual drug resistant cell lines. A selection method of gradually increasing drug doses was implemented to avoid clonal selection. Resistance was confirmed using a clonogenic assay. Changes in gene expression associated with the development of drug resistance were determined by microarray analysis. Changes in the expression of selected genes were validated by Quantitative Real-Time Polymerase Chain Reaction (QPCR and immunoblotting. Results Three isogenic cell lines were developed and resistance to each drug or the combination of drugs was confirmed. Development of resistance was accompanied by a reduced growth rate. The microarray and QPCR analyses showed that unique changes in gene expression occurred in the dual drug resistant cell line and that genes known to be involved in resistance could be identified in all cell lines. Conclusions Ovarian tumor cells can acquire resistance to both carboplatin and docetaxel when selected in the presence of both agents. Distinct changes in gene expression occur in the dual resistant cell line indicating that dual resistance is not a simple combination of the changes observed in cell lines exhibiting single agent resistance.

  11. Photovoltaic building blocks

    DEFF Research Database (Denmark)

    Hanberg, Peter Jesper; Jørgensen, Anders Michael

    2014-01-01

    it directcompetitive with fossil energy sources a further reduction is needed. By increasing the efficiency of the solar cells one gain an advantage through the whole chain of cost. So that per produced Watt of power less material is spent, installation costs are lower, less area is used etc. With an average...... efficiency of about 15% for commercial Silicon solar cells there is still much to gain. DTU Danchip provides research facilities, equipment and expertise for the building blocks that comprises fabricating the efficient solar cell. In order to get more of the sun light into the device we provide thin film......Photovoltaics (PV), better known as solar cells, are now a common day sight on many rooftops in Denmark.The installed capacity of PV systems worldwide is growing exponentially1 and is the third most importantrenewable energy source today. The cost of PV is decreasing fast with ~10%/year but to make...

  12. Anode interfacial tuning via electron-blocking/hole-transport layers and indium tin oxide surface treatment in bulk-heterojunction organic photovoltaic cells

    Energy Technology Data Exchange (ETDEWEB)

    Hains, Alexander W.; Liu, Jun; Martinson, Alex B.F.; Irwin, Michael D.; Marks, Tobin J. [Department of Chemistry and the Materials Research Center, Northwestern University, Evanston, Illinois (United States)

    2010-02-22

    The effects of anode/active layer interface modification in bulk-heterojunction organic photovoltaic (OPV) cells is investigated using poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) and/or a hole-transporting/electron-blocking blend of 4,4'-bis[(p-trichlorosilylpropylphenyl)-phenylamino]biphenyl (TPDSi{sub 2}) and poly[9,9-dioctylfluorene-co-N-[4-(3-methylpropyl)]-diphenylamine] (TFB) as interfacial layers (IFLs). Current-voltage data in the dark and AM1.5G light show that the TPDSi{sub 2}:TFB IFL yields MDMO-PPV:PCBM OPVs with substantially increased open-circuit voltage (V{sub oc}), power conversion efficiency, and thermal stability versus devices having no IFL or PEDOT:PSS. Using PEDOT:PSS and TPDSi{sub 2}:TFB together in the same cell greatly reduces dark current and produces the highest V{sub oc} (0.91 V) by combining the electron-blocking effects of both layers. ITO anode pre-treatment was investigated by X-ray photoelectron spectroscopy to understand why oxygen plasma, UV ozone, and solvent cleaning markedly affect cell response in combination with each IFL. O{sub 2} plasma and UV ozone treatment most effectively clean the ITO surface and are found most effective in preparing the surface for PEDOT:PSS deposition; UV ozone produces optimum solar cells with the TPDSi{sub 2}:TFB IFL. Solvent cleaning leaves significant residual carbon contamination on the ITO and is best followed by O{sub 2} plasma or UV ozone treatment. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  13. Inter and Intra Molecular Phase Separation Environment Effects on PI-PEO Block Copolymers for Batteries and Fuel Cells

    Science.gov (United States)

    Xue, Chen-Chen; Meador, Mary Ann B.; Eby, R. K.; Cheng, Stephen Z. D.; Ge, Jason J.; Cubon, Valerie A.

    2002-01-01

    Rod-coil molecules have been introduced as a novel type of block copolymers with unique microstructure due to their ability to self-assemble to various ordered morphologies on a nanometer length scale. These molecules, comprised two homo polymers joined together at one end, microphase separate into ordered, periodic arrays of spheres, cylinders in the bulk state and or solution. To get ordered structure in a reasonable scale, additional force field are applied, such as mechanical shearing, electric field and magnetic field. Recently, progress has made it a possible to develop a new class of polyimides (PI)-Polyethylene oxide (PEO) that are soluble in polar organic solvents. The solvent-soluble PI-PEO has a wide variety of applications in microelectronics, since these PI-PEO films exhibit a high degree of thermal and chemical stability. In this paper, we report the self-assembled ordered structure of PI-PEO molecules formed from concentrate solution.

  14. Propane Fuel Cells: Selectivity for Partial or Complete Reaction

    Directory of Open Access Journals (Sweden)

    Shadi Vafaeyan

    2014-01-01

    Full Text Available The use of propane fuel in high temperature (120°C polymer electrolyte membrane (PEM fuel cells that do not require a platinum group metal catalyst is being investigated in our laboratory. Density functional theory (DFT was used to determine propane adsorption energies, desorption energies, and transition state energies for both dehydrogenation and hydroxylation reactions on a Ni(100 anode catalyst surface. The Boltzmann factor for the hydroxylation of a propyl species to form propanol and its subsequent desorption was compared to that for the dehydrogenation of a propyl species. The large ratio of the respective Boltzmann factors indicated that the formation of a completely reacted product (carbon dioxide is much more likely than the formation of partially reacted products (alcohols, aldehydes, carboxylic acids, and carbon monoxide. That finding is evidence for the major proportion of the chemical energy of the propane fuel being converted to either electrical or thermal energy in the fuel cell rather than remaining unused when partially reacted species are formed.

  15. NCCN Evidence Blocks.

    Science.gov (United States)

    Carlson, Robert W; Jonasch, Eric

    2016-05-01

    NCCN has developed a series of Evidence Blocks: graphics that provide ratings for each recommended treatment regimen in terms of efficacy, toxicity, quality and consistency of the supporting data, and affordability. The NCCN Evidence Blocks are currently available in 10 tumor types within the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines). At a glance, patients and providers can understand how a given treatment was assessed by the NCCN Guidelines Panel and get a sense of how a given treatment may match individual needs and preferences. Robert W. Carlson, MD, CEO of NCCN, described the reasoning behind this new feature and how the tool is used, and Eric Jonasch, MD, Professor of Genitourinary Medical Oncology at The University of Texas MD Anderson Cancer Center, and Vice Chair of the NCCN Kidney Cancer Panel, described its applicability in the management of metastatic renal cell carcinoma. PMID:27226499

  16. Selective enrichment of hepatoeytes from mouse embryonic stem cells with a culture system containing cholestatic serum

    Institute of Scientific and Technical Information of China (English)

    Jun MIN; Er-wei SONG; Ji-sheng CHEN; Chang-zhen SHANG; Ya-jin CHEN; Lei ZHANG; Lu LIU; Xiao-geng DENG; Mei YANG; Dong-ping CHEN; Jun CAO

    2007-01-01

    Aim: There is increasing evidence indicating that embryonic stem (ES) cells are capable of differentiating into hepatocyte-like cells in vitro. However, it is neces- sary to improve the differentiation efficiency so as to promote the clinical application. Here, we report an efficient culture system to support hepatocyte differentiation from ES cells by utilizing cholestatic serum. Methods: One week after the induction of El4 mouse ES cells into hepatocytes with sodium butyrate, cholestatic serum was added into the culture system at various concentrations and hepatocyte-like cells were induced to proliferate. The morphological and phenotypic markers of hepatocytes were characterized using light microscopy, immunocytochemistry, and RT-PCR, respectively. The function of glycogen stor- age of the differentiated cells was detected by Periodic acid-Schiff (PAS) reaction, and the ratio of hepatic differentiation was determined by counting the albumin and PAS-positive cells. Results: In the presence of conditional selective medium containing cholestatic serum, numerous epithelial cells resembling hepatocytes were observed. The RT-PCR analysis showed that undifferentiated ES cells did not express any hepatic-specific markers; however, in the presence of sodium butyrate and conditional selective medium containing cholestatic serum, hepatic differentiation markers were detected. Immunofluorescence staining showed that those ES-derived hepatocytes were α-fetoprotein, albumin, and cytokeratin 18 positive, with the ability of storing glycogen. Further determination of the hepatic differentiation ratio showed that the application of cholestatic serum efficiently enriched ES-derived hepatocyte-like cells by inducing lineage differentiation and enhancing lineage proliferation. Conclusion: The conditional selective medium containing cholestatic serum is optimal to selectively enrich hepatocyte-like cells from mixed differentiated ES cells, which may provide a novel method to

  17. Strategies for selecting recombinant CHO cell lines for cGMP manufacturing: improving the efficiency of cell line generation.

    Science.gov (United States)

    Porter, Alison J; Racher, Andrew J; Preziosi, Richard; Dickson, Alan J

    2010-01-01

    Transfectants with a wide range of cellular phenotypes are obtained during the process of cell line generation. For the successful manufacture of a therapeutic protein, a means is required to identify a cell line with desirable growth and productivity characteristics from this phenotypically wide-ranging transfectant population. This identification process is on the critical path for first-in-human studies. We have stringently examined a typical selection strategy used to isolate cell lines suitable for cGMP manufacturing. One-hundred and seventy-five transfectants were evaluated as they progressed through the different assessment stages of the selection strategy. High producing cell lines, suitable for cGMP manufacturing, were identified. However, our analyses showed that the frequency of isolation of the highest producing cell lines was low and that ranking positions were not consistent between each assessment stage, suggesting that there is potential to improve upon the strategy. Attempts to increase the frequency of isolation of the 10 highest producing cell lines, by in silico analysis of alternative selection strategies, were unsuccessful. We identified alternative strategies with similar predictive capabilities to the typical selection strategy. One alternate strategy required fewer cell lines to be progressed at the assessment stages but the stochastic nature of the models means that cell line numbers are likely to change between programs. In summary, our studies illuminate the potential for improvement to this and future selection strategies, based around use of assessments that are more informative or that reduce variance, paving the way to improved efficiency of generation of manufacturing cell lines. PMID:20623584

  18. An air-stable inverted photovoltaic device using ZnO as the electron selective layer and MoO3 as the blocking layer

    Institute of Scientific and Technical Information of China (English)

    SONG Peng-fei; QIN Wen-jing; DING Guo-jing; YAN Qi-qi; YANG Li-ying; YIN Shou-gen

    2011-01-01

    An air-stable photovoltaic device based on znic oxide nanoparticles(ZNP) in an inverted structure of indium tin oxide (ITO)/ZnO/poly(3-hexylthiophene)(P3HT):[6,6]-phenyl C61-butyric acid methyl ester(PCBM)/MoO3/Ag is studied.We find that the optimum thickness of the MoO3 layer is 2 nm.When the MoO3 blocking layer is introduced,the fill factor of the devices is increased from 29% to 40%,the power conversion efficiency is directly promoted from 0.35% to 1.27%.The stability under ambient conditions of this inverted structure device much is better due to the improved stability at the polymer/Ag interface.The enhancement is attributed to the high carriers mobility and suitable band gap of MoO3 layer.

  19. Back-junction back-contact n-type silicon solar cell with diffused boron emitter locally blocked by implanted phosphorus

    Science.gov (United States)

    Müller, Ralph; Schrof, Julian; Reichel, Christian; Benick, Jan; Hermle, Martin

    2014-09-01

    The highest energy conversion efficiencies in the field of silicon-based photovoltaics have been achieved with back-junction back-contact (BJBC) silicon solar cells by several companies and research groups. One of the most complex parts of this cell structure is the fabrication of the locally doped p- and n-type regions, both on the back side of the solar cell. In this work, we introduce a process sequence based on a synergistic use of ion implantation and furnace diffusion. This sequence enables the formation of all doped regions for a BJBC silicon solar cell in only three processing steps. We observed that implanted phosphorus can block the diffusion of boron atoms into the silicon substrate by nearly three orders of magnitude. Thus, locally implanted phosphorus can be used as an in-situ mask for a subsequent boron diffusion which simultaneously anneals the implanted phosphorus and forms the boron emitter. BJBC silicon solar cells produced with such an easy-to-fabricate process achieved conversion efficiencies of up to 21.7%. An open-circuit voltage of 674 mV and a fill factor of 80.6% prove that there is no significant recombination at the sharp transition between the highly doped emitter and the highly doped back surface field at the device level.

  20. Back-junction back-contact n-type silicon solar cell with diffused boron emitter locally blocked by implanted phosphorus

    Energy Technology Data Exchange (ETDEWEB)

    Müller, Ralph, E-mail: ralph.mueller@ise.fraunhofer.de; Schrof, Julian; Reichel, Christian; Benick, Jan; Hermle, Martin [Fraunhofer Institute for Solar Energy Systems, Heidenhofstrasse 2, Freiburg D-79110 (Germany)

    2014-09-08

    The highest energy conversion efficiencies in the field of silicon-based photovoltaics have been achieved with back-junction back-contact (BJBC) silicon solar cells by several companies and research groups. One of the most complex parts of this cell structure is the fabrication of the locally doped p- and n-type regions, both on the back side of the solar cell. In this work, we introduce a process sequence based on a synergistic use of ion implantation and furnace diffusion. This sequence enables the formation of all doped regions for a BJBC silicon solar cell in only three processing steps. We observed that implanted phosphorus can block the diffusion of boron atoms into the silicon substrate by nearly three orders of magnitude. Thus, locally implanted phosphorus can be used as an in-situ mask for a subsequent boron diffusion which simultaneously anneals the implanted phosphorus and forms the boron emitter. BJBC silicon solar cells produced with such an easy-to-fabricate process achieved conversion efficiencies of up to 21.7%. An open-circuit voltage of 674 mV and a fill factor of 80.6% prove that there is no significant recombination at the sharp transition between the highly doped emitter and the highly doped back surface field at the device level.

  1. Activation of Robo1 signaling of breast cancer cells by Slit2 from stromal fibroblast restrains tumorigenesis via blocking PI3K/Akt/β-catenin pathway.

    Science.gov (United States)

    Chang, Po-Hao; Hwang-Verslues, Wendy W; Chang, Yi-Cheng; Chen, Chun-Chin; Hsiao, Michael; Jeng, Yung-Ming; Chang, King-Jen; Lee, Eva Y-H P; Shew, Jin-Yuh; Lee, Wen-Hwa

    2012-09-15

    Tumor microenvironment plays a critical role in regulating tumor progression by secreting factors that mediate cancer cell growth. Stromal fibroblasts can promote tumor growth through paracrine factors; however, restraint of malignant carcinoma progression by the microenvironment also has been observed. The mechanisms that underlie this paradox remain unknown. Here, we report that the tumorigenic potential of breast cancer cells is determined by an interaction between the Robo1 receptor and its ligand Slit2, which is secreted by stromal fibroblasts. The presence of an active Slit2/Robo1 signal blocks the translocation of β-catenin into nucleus, leading to downregulation of c-myc and cyclin D1 via the phosphoinositide 3-kinase (PI3K)/Akt pathway. Clinically, high Robo1 expression in the breast cancer cells correlates with increased survival in patients with breast cancer, and low Slit2 expression in the stromal fibroblasts is associated with lymph node metastasis. Together, our findings explain how a specific tumor microenvironment can restrain a given type of cancer cell from progression and show that both stromal fibroblasts and tumor cell heterogeneity affect breast cancer outcomes.

  2. Astragalus polysaccharides suppress ICAM-1 and VCAM-1 expression in TNF-α-treated human vascular endothelial cells by blocking NF-KB activation

    Institute of Scientific and Technical Information of China (English)

    Yu-ping ZHU; Tao SHEN; Ya-jun LIN; Bei-dong CHEN; Yang RUAN; Yuan CAO; Yue QIAO

    2013-01-01

    Aim:To investigate the effects ofAstragalus polysaccharides (APS) on tumor necrosis factor (TNF)-α-induced inflammatory reactions in human umbilical vein endothelial cells (HUVECs) and to elucidate the underlying mechanisms.Methods:HUVECs were treated with TNF-α for 24 h.The amounts of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1(VCAM-1) were determined with Western blotting.HUVEC viability and apoptosis were detected using cell viability assay and Hoechst staining,respectively.Reactive oxygen species (ROS) production was measured by DHE staining.Monocyte and HUVEC adhesion assay was used to detect endothelial cell adhesive function.NF-KB activation was detected with immunofluorescence.Results:TNF-α (1-80 ng/mL) caused dose-and time-dependent increases of ICAM-1 and VCAM-1 expression in HUVECs,accompanied by significant augmentation of IKB phosphorylation and NF-KB translocation into the nuclei.Pretreatment with APS (10 and 50 μg/mL)significantly attenuated TNFα-induced upregulation of ICAM-1,VCAM-1,and NF-KB translocation.Moreover,APS significantly reduced apoptosis,ROS generation and adhesion function damage in TNF-α-treated HUVECs.Conclusion:APS suppresses TNFα-induced adhesion molecule expression by blocking NF-KB signaling and inhibiting ROS generation in HUVECs.The results suggest that APS may be used to treat and prevent endothelial cell injury-related diseases.

  3. Induction and selection of mutants from in vitro cultured plant cells

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yung Il; Kim, Jae Sung; Shin, In Chul; Lee, Sang Jae [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1994-07-01

    Mutant cell lines are useful for biochemical, physiological and genetical material for marker in various genetic manipulation experiments and for the direct use in crop plant improvement. Mutant selection may lead to the production of plants showing resistance or tolerance to specific environmental stress, such as solinity, drought, toxed metals, herbicides, pathogens and low temperature. In this review, these included the production of the somatic variation, the selection process itself and stability of the selected characters in cell culture and regenerated plant. Which would seem to be useful for improving plants and securring genetic resources. 45 refs. (Author).

  4. A water-processable organic electron-selective layer for solution-processed inverted organic solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Dongcheng; Zhou, Hu; Cai, Ping; Sun, Shi; Ye, Hua; Su, Shi-Jian, E-mail: mssjsu@scut.edu.cn; Cao, Yong [State Key Laboratory of Luminescent Materials and Devices (South China University of Technology) and Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou 510640 (China)

    2014-02-03

    A triazine- and pyridinium-containing water-soluble material of 1,1′,1″-(4,4′,4″-(1,3,5-triazine-2,4,6-triyl)tris(benzene-4,1-diyl)) tris(methylene)tripyridinium bromide (TzPyBr) was developed as an organic electron-selective layer in solution-processed inverted organic solar cells due to its strong anti-erosion capacity against non-polar organic solvents commonly used for the active layer. Ohmic-like contact with the adjacent active materials like fullerene derivatives is speculated to be formed, as confirmed by the work-function measurements with scanning Kelvin probe and ultraviolet photoelectron spectroscopy techniques. Besides, considering the deep highest occupied molecular orbital energy level of TzPyBr, excellent hole-blocking property of the electron-selective layer is also anticipated. The inverted organic photovoltaic devices based on the TzPyBr/ITO (indium tin oxide) bilayer cathode exhibit dramatically enhanced performance compared to the control devices with bare ITO as the cathode and even higher efficiency than the conventional type devices with ITO and Al as the electrodes.

  5. Selective control of the apoptosis signaling network in heterogeneous cell populations.

    Directory of Open Access Journals (Sweden)

    Diego Calzolari

    Full Text Available BACKGROUND: Selective control in a population is the ability to control a member of the population while leaving the other members relatively unaffected. The concept of selective control is developed using cell death or apoptosis in heterogeneous cell populations as an example. Control of apoptosis is essential in a variety of therapeutic environments, including cancer where cancer cell death is a desired outcome and Alzheimer's disease where neuron survival is the desired outcome. However, in both cases these responses must occur with minimal response in other cells exposed to treatment; that is, the response must be selective. METHODOLOGY AND PRINCIPAL FINDINGS: Apoptosis signaling in heterogeneous cells is described by an ensemble of gene networks with identical topology but different link strengths. Selective control depends on the statistics of signaling in the ensemble of networks, and we analyze the effects of superposition, non-linearity and feedback on these statistics. Parallel pathways promote normal statistics while series pathways promote skew distributions, which in the most extreme cases become log-normal. We also show that feedback and non-linearity can produce bimodal signaling statistics, as can discreteness and non-linearity. Two methods for optimizing selective control are presented. The first is an exhaustive search method and the second is a linear programming based approach. Though control of a single gene in the signaling network yields little selectivity, control of a few genes typically yields higher levels of selectivity. The statistics of gene combinations susceptible to selective control in heterogeneous apoptosis networks is studied and is used to identify general control strategies. CONCLUSIONS AND SIGNIFICANCE: We have explored two methods for the study of selectivity in cell populations. The first is an exhaustive search method limited to three node perturbations. The second is an effective linear model, based on

  6. Selective effect of cell membrane on synaptic neurotransmission

    Science.gov (United States)

    Postila, Pekka A.; Vattulainen, Ilpo; Róg, Tomasz

    2016-01-01

    Atomistic molecular dynamics simulations were performed with 13 non-peptidic neurotransmitters (NTs) in three different membrane environments. The results provide compelling evidence that NTs are divided into membrane-binding and membrane-nonbinding molecules. NTs adhere to the postsynaptic membrane surface whenever the ligand-binding sites of their synaptic receptors are buried in the lipid bilayer. In contrast, NTs that have extracellular ligand-binding sites do not have a similar tendency to adhere to the membrane surface. This finding is a seemingly simple yet important addition to the paradigm of neurotransmission, essentially dividing it into membrane-independent and membrane-dependent mechanisms. Moreover, the simulations also indicate that the lipid composition especially in terms of charged lipids can affect the membrane partitioning of NTs. The revised paradigm, highlighting the importance of cell membrane and specific lipids for neurotransmission, should to be of interest to neuroscientists, drug industry and the general public alike.

  7. A20 inhibits human salivary adenoid cystic carcinoma cells invasion via blocking nuclear factor-κB activation

    Institute of Scientific and Technical Information of China (English)

    ZHANG Bin; GUAN Cheng-chao; CHEN Wan-tao; ZHANG Ping; YAN Ming; SHI Jiu-hui; QIN Chun-lin; YANG Qian

    2007-01-01

    Background A20, also known as tumor necrosis factor α induced protein 3 (TNFaip3), is a cytoplasmic zinc finger protein that inhibits nuclear factor kappa-B (NF-κB) activity and prevents tumor necrosis factor (TNF)-mediated programmed cell death. NF-κB is a transcription factor that regulates expression of genes involved in cell proliferation,cell survival and anti-apoptosis. Several studies have implicated that the NF-κB signal pathway is associated with angiogenesis and clinico-pathological process of adenoid cystic carcinoma (ACC) of the salivary glands.Methods The ability of overexpression of A20 to influence the biological behavior and invasion of ACC cells was examined. The cells were stably transfected with full-length A20 cDNA. Stable gene transfer was verified by realtime-polymerase chain reaction (PCR) and Western blot analysis. The change of cell biological behavior was examined by methyl thiazolyl tetrazolium (MTT) and NF-κB luciferase reporter assay and the invasion of the cells was examined by a Matrigel invasion chamber.Results pEGPFN3-A20 gene was stably transferred into ACC-2 cells and overexpressed. When cells were treated with TNFα, the NF-κB activity of ACC-2-A20 cells could be down-regulated about 46.32% in contrast to ACC-2-GFP cells (P<0.05). A20 potently inhibited growth of A20 transfectant ACC-2-A20 compared with control vector transfected groups and the ACC-2 empty control group (P<0.05). The ACC-2-A20 cells showed significantly reduced ability to invade through Matrigei-coated filters compared to ACC-2-GFP and ACC-2 cells. The inhibition rate was up to 71.05% (P<0.05).Conclusions A20 gene transfer is associated with decreased tumor invasion, in part via the down-regulation of NF-κB expression, providing evidence for a potential application of A20 in designing a treatment modality for salivary gland cancers such as ACC.

  8. CORE SATURATION BLOCKING OSCILLATOR

    Science.gov (United States)

    Spinrad, R.J.

    1961-10-17

    A blocking oscillator which relies on core saturation regulation to control the output pulse width is described. In this arrangement an external magnetic loop is provided in which a saturable portion forms the core of a feedback transformer used with the thermionic or semi-conductor active element. A first stationary magnetic loop establishes a level of flux through the saturation portion of the loop. A second adjustable magnet moves the flux level to select a saturation point giving the desired output pulse width. (AEC)

  9. 22. Proteomic Analysis of Differential Protein Expression in vero Cell with Antisense Blocking of Relevant Gene Involved in inhibition of Nontargeted Mutagenesis

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Objective: Recent studies have demonstrated that cells exposed to ionizing radiation or alkylating agents can develop prolonged genetic instability. But its mechanism is still unknown. A cDNA fragment (fragment 9) has been isolated in MNNG-exposed vero cell by mRNA differential display in this lab. After antisense blocking the expression of its relevant gene (fragment 9 related gene, FNR gene), we found that nontargeted mutation frequency induced by MNNG was enhanced significantly. which implicated that the product of the blocked gene may be involved in the inhibition of nontargeted mutation. In order to elucidate the functional mechanism of the FNR gene, we try to separate the proteins from the established cell line expressing antisense fragment 9 to find out the FNR gene-coded protein. Method: The total cellular proteins of MNNG-exposed vero cell transfected with antisense RNA expression plasmid (vero-pM-amp--9-) and those with vector DNA (vero-pM-amp-) were separated by two-dimensional gel electrophoresis, and the resulting maps were analyzed with 2-D analysis software packages to find out the differentially expressed protein spots. Then the related 2-D PAGE database (http://biobase.dk/cgi-bin/celis/) was searched according to the protein spots information obtained from 2-DE including the position in the gel, isoelectric point (pl) and molecular weight (Mr). Result: Twelve proteins were specifically expressed only in vero-pM-amp-, and 2 proteins in vero-pM-amp--9-. In addition, there were 24 proteins expressed in higher level in vero-pM-amp--9- as compared with vero-pM-amp- (P<0.05), among them the expression of 7 proteins were enhanced by greater than 5 folds. On the other hand, no sequence similarity was found by homology analysis in GenBank through comparing the fragment 9 with the cDNA sequences of those proteins found in this study. Conclusion: Gene expression alterations bave occurred after antisense blocking of the FNR gene expression as demonstrated by

  10. Hypoxia selects bortezomib-resistant stem cells of chronic myeloid leukemia.

    Directory of Open Access Journals (Sweden)

    Michele Tanturli

    Full Text Available We previously demonstrated that severe hypoxia inhibits growth of Chronic Myeloid Leukemia (CML cells and selects stem cells where BCR/Abl(protein is suppressed, although mRNA is not, so that hypoxia-selected stem cells, while remaining leukemic, are independent of BCR/Abl signaling and thereby refractory to Imatinib-mesylate. The main target of this study was to address the effects of the proteasome inhibitor Bortezomib (BZ on the maintenance of stem or progenitor cells in hypoxic primary cultures (LC1, by determining the capacity of LC1 cells to repopulate normoxic secondary cultures (LC2 and the kinetics of this repopulation. Unselected K562 cells from day-2 hypoxic LC1 repopulated LC2 with rapid, progenitor-type kinetics; this repopulation was suppressed by BZ addition to LC1 at time 0, but completely resistant to day-1 BZ, indicating that progenitors require some time to adapt to stand hypoxia. K562 cells selected in hypoxic day-7 LC1 repopulated LC2 with stem-type kinetics, which was largely resistant to BZ added at either time 0 or day 1, indicating that hypoxia-selectable stem cells are BZ-resistant per se, i.e. before their selection. Furthermore, these cells were completely resistant to day-6 BZ, i.e. after selection. On the other hand, hypoxia-selected stem cells from CD34-positive cells of blast-crisis CML patients appeared completely resistant to either time-0 or day-1 BZ. To exploit in vitro the capacity of CML cells to adapt to hypoxia enabled to detect a subset of BZ-resistant leukemia stem cells, a finding of particular relevance in light of the fact that our experimental system mimics the physiologically hypoxic environment of bone marrow niches where leukemia stem cells most likely home and sustain minimal residual disease in vivo. This suggests the use of BZ as an enhanced strategy to control CML. in particular to prevent relapse of disease, to be considered with caution and to need further deepening.

  11. Blocking junctional adhesion molecule C enhances dendritic cell migration and boosts the immune responses against Leishmania major.

    Directory of Open Access Journals (Sweden)

    Romain Ballet

    2014-12-01

    Full Text Available The recruitment of dendritic cells to sites of infections and their migration to lymph nodes is fundamental for antigen processing and presentation to T cells. In the present study, we showed that antibody blockade of junctional adhesion molecule C (JAM-C on endothelial cells removed JAM-C away from junctions and increased vascular permeability after L. major infection. This has multiple consequences on the output of the immune response. In resistant C57BL/6 and susceptible BALB/c mice, we found higher numbers of innate immune cells migrating from blood to the site of infection. The subsequent migration of dendritic cells (DCs from the skin to the draining lymph node was also improved, thereby boosting the induction of the adaptive immune response. In C57BL/6 mice, JAM-C blockade after L. major injection led to an enhanced IFN-γ dominated T helper 1 (Th1 response with reduced skin lesions and parasite burden. Conversely, anti JAM-C treatment increased the IL-4-driven T helper 2 (Th2 response in BALB/c mice with disease exacerbation. Overall, our results show that JAM-C blockade can finely-tune the innate cell migration and accelerate the consequent immune response to L. major without changing the type of the T helper cell response.

  12. S100A7-downregulation inhibits epidermal growth factor-induced signaling in breast cancer cells and blocks osteoclast formation.

    Directory of Open Access Journals (Sweden)

    Vikram Paruchuri

    Full Text Available S100A7 is a small calcium binding protein, which has been shown to be differentially expressed in psoriatic skin lesions, as well as in squamous cell tumors of the skin, lung and breast. Although its expression has been correlated to HER+ high-grade tumors and to a high risk of progression, the molecular mechanisms of these S100A7-mediated tumorigenic effects are not well known. Here, we showed for the first time that epidermal growth factor (EGF induces S100A7 expression in both MCF-7 and MDA-MB-468 cell lines. We also observed a decrease in EGF-directed migration in shRNA-downregulated MDA-MB-468 cell lines. Furthermore, our signaling studies revealed that EGF induced simultaneous EGF receptor phosphorylation at Tyr1173 and HER2 phosphorylation at Tyr1248 in S100A7-downregulated cell lines as compared to the vector-transfected controls. In addition, reduced phosphorylation of Src at tyrosine 416 and p-SHP2 at tyrosine 542 was observed in these downregulated cell lines. Further studies revealed that S100A7-downregulated cells had reduced angiogenesis in vivo based on matrigel plug assays. Our results also showed decreased tumor-induced osteoclastic resorption in an intra-tibial bone injection model involving SCID mice. S100A7-downregulated cells had decreased osteoclast number and size as compared to the vector controls, and this decrease was associated with variations in IL-8 expression in in vitro cell cultures. This is a novel report on the role of S100A7 in EGF-induced signaling in breast cancer cells and in osteoclast formation.

  13. Fine tuning of the threshold of T cell selection by the Nck adapters.

    Science.gov (United States)

    Roy, Edwige; Togbe, Dieudonnée; Holdorf, Amy; Trubetskoy, Dmitry; Nabti, Sabrina; Küblbeck, Günter; Schmitt, Sabine; Kopp-Schneider, Annette; Leithäuser, Frank; Möller, Peter; Bladt, Friedhelm; Hämmerling, Günter J; Arnold, Bernd; Pawson, Tony; Tafuri, Anna

    2010-12-15

    Thymic selection shapes the T cell repertoire to ensure maximal antigenic coverage against pathogens while preventing autoimmunity. Recognition of self-peptides in the context of peptide-MHC complexes by the TCR is central to this process, which remains partially understood at the molecular level. In this study we provide genetic evidence that the Nck adapter proteins are essential for thymic selection. In vivo Nck deletion resulted in a reduction of the thymic cellularity, defective positive selection of low-avidity T cells, and impaired deletion of thymocytes engaged by low-potency stimuli. Nck-deficient thymocytes were characterized by reduced ERK activation, particularly pronounced in mature single positive thymocytes. Taken together, our findings identify a crucial role for the Nck adapters in enhancing TCR signal strength, thereby fine-tuning the threshold of thymocyte selection and shaping the preimmune T cell repertoire. PMID:21078909

  14. Fine tuning of the threshold of T cell selection by the Nck adapters.

    Science.gov (United States)

    Roy, Edwige; Togbe, Dieudonnée; Holdorf, Amy; Trubetskoy, Dmitry; Nabti, Sabrina; Küblbeck, Günter; Schmitt, Sabine; Kopp-Schneider, Annette; Leithäuser, Frank; Möller, Peter; Bladt, Friedhelm; Hämmerling, Günter J; Arnold, Bernd; Pawson, Tony; Tafuri, Anna

    2010-12-15

    Thymic selection shapes the T cell repertoire to ensure maximal antigenic coverage against pathogens while preventing autoimmunity. Recognition of self-peptides in the context of peptide-MHC complexes by the TCR is central to this process, which remains partially understood at the molecular level. In this study we provide genetic evidence that the Nck adapter proteins are essential for thymic selection. In vivo Nck deletion resulted in a reduction of the thymic cellularity, defective positive selection of low-avidity T cells, and impaired deletion of thymocytes engaged by low-potency stimuli. Nck-deficient thymocytes were characterized by reduced ERK activation, particularly pronounced in mature single positive thymocytes. Taken together, our findings identify a crucial role for the Nck adapters in enhancing TCR signal strength, thereby fine-tuning the threshold of thymocyte selection and shaping the preimmune T cell repertoire.

  15. Anti-coreceptor therapy drives selective T cell egress by suppressing inflammation-dependent chemotactic cues

    Science.gov (United States)

    Martin, Aaron J.; Clark, Matthew; Gojanovich, Gregory; Manzoor, Fatima; Miller, Keith; Kline, Douglas E.; Morillon, Y. Maurice; Wang, Bo

    2016-01-01

    There continues to be a need for immunotherapies to treat type 1 diabetes in the clinic. We previously reported that nondepleting anti-CD4 and -CD8 Ab treatment effectively reverses diabetes in new-onset NOD mice. A key feature of the induction of remission is the egress of the majority of islet-resident T cells. How this occurs is undefined. Herein, the effects of coreceptor therapy on islet T cell retention were investigated. Bivalent Ab binding to CD4 and CD8 blocked TCR signaling and T cell cytokine production, while indirectly downregulating islet chemokine expression. These processes were required for T cell retention, as ectopic IFN-γ or CXCL10 inhibited Ab-mediated T cell purging. Importantly, treatment of humanized mice with nondepleting anti–human CD4 and CD8 Ab similarly reduced tissue-infiltrating human CD4+ and CD8+ T cells. These findings demonstrate that Ab binding of CD4 and CD8 interrupts a feed-forward circuit by suppressing T cell–produced cytokines needed for expression of chemotactic cues, leading to rapid T cell egress from the islets. Coreceptor therapy therefore offers a robust approach to suppress T cell–mediated pathology by purging T cells in an inflammation-dependent manner.

  16. Selective activation of p120ctn-Kaiso signaling to unlock contact inhibition of ARPE-19 cells without epithelial-mesenchymal transition.

    Science.gov (United States)

    Chen, Hung-Chi; Zhu, Ying-Ting; Chen, Szu-Yu; Tseng, Scheffer C G

    2012-01-01

    Contact-inhibition ubiquitously exists in non-transformed cells and explains the poor regenerative capacity of in vivo human retinal pigment epithelial cells (RPE) during aging, injury and diseases. RPE injury or degeneration may unlock mitotic block mediated by contact inhibition but may also promote epithelial-mesenchymal transition (EMT) contributing to retinal blindness. Herein, we confirmed that EMT ensued in post-confluent ARPE-19 cells when contact inhibition was disrupted with EGTA followed by addition of EGF and FGF-2 because of activation of canonical Wnt and Smad/ZEB signaling. In contrast, knockdown of p120-catenin (p120) unlocked such mitotic block by activating p120/Kaiso, but not activating canonical Wnt and Smad/ZEB signaling, thus avoiding EMT. Nuclear BrdU labeling was correlated with nuclear release of Kaiso through p120 nuclear translocation, which was associated with activation of RhoA-ROCK signaling, destabilization of microtubules. Prolonged p120 siRNA knockdown followed by withdrawal further expanded RPE into more compact monolayers with a normal phenotype and a higher density. This new strategy based on selective activation of p120/Kaiso but not Wnt/β-catenin signaling obviates the need of using single cells and the risk of EMT, and may be deployed to engineer surgical grafts containing RPE and other tissues. PMID:22590627

  17. Selective activation of p120ctn-Kaiso signaling to unlock contact inhibition of ARPE-19 cells without epithelial-mesenchymal transition.

    Directory of Open Access Journals (Sweden)

    Hung-Chi Chen

    Full Text Available Contact-inhibition ubiquitously exists in non-transformed cells and explains the poor regenerative capacity of in vivo human retinal pigment epithelial cells (RPE during aging, injury and diseases. RPE injury or degeneration may unlock mitotic block mediated by contact inhibition but may also promote epithelial-mesenchymal transition (EMT contributing to retinal blindness. Herein, we confirmed that EMT ensued in post-confluent ARPE-19 cells when contact inhibition was disrupted with EGTA followed by addition of EGF and FGF-2 because of activation of canonical Wnt and Smad/ZEB signaling. In contrast, knockdown of p120-catenin (p120 unlocked such mitotic block by activating p120/Kaiso, but not activating canonical Wnt and Smad/ZEB signaling, thus avoiding EMT. Nuclear BrdU labeling was correlated with nuclear release of Kaiso through p120 nuclear translocation, which was associated with activation of RhoA-ROCK signaling, destabilization of microtubules. Prolonged p120 siRNA knockdown followed by withdrawal further expanded RPE into more compact monolayers with a normal phenotype and a higher density. This new strategy based on selective activation of p120/Kaiso but not Wnt/β-catenin signaling obviates the need of using single cells and the risk of EMT, and may be deployed to engineer surgical grafts containing RPE and other tissues.

  18. Black silicon laser-doped selective emitter solar cell with 18.1% efficiency

    DEFF Research Database (Denmark)

    Davidsen, Rasmus Schmidt; Li, Hongzhao; To, Alexander;

    2016-01-01

    We report fabrication of nanostructured, laser-doped selective emitter (LDSE) silicon solar cells with power conversion efficiency of 18.1% and a fill factor (FF) of 80.1%. The nanostructured solar cells were realized through a single step, mask-less, scalable reactive ion etch (RIE) texturing......-texturing as well as the LDSE process, we consider this specific combination a promising candidate for a cost-efficient process for future Si solar cells....

  19. Selective Retention of Bone Marrow-Derived Cells to Enhance Spinal Fusion

    OpenAIRE

    Muschler, George F.; Matsukura, Yoichi; Nitto, Hironori; Boehm, Cynthia A.; Valdevit, Antonio D.; Kambic, Helen E.; Davros, William J.; Easley, Kirk A.; Powell, Kimerly A.

    2005-01-01

    Connective tissue progenitors can be concentrated rapidly from fresh bone marrow aspirates using some porous matrices as a surface for cell attachment and selective retention, and for creating a cellular graft that is enriched with respect to the number of progenitor cells. We evaluated the potential value of this method using demineralized cortical bone powder as the matrix. Matrix alone, matrix plus marrow, and matrix enriched with marrow cells were compared in an established canine spinal ...

  20. Blocking interaction of viral gp120 and CD4-expressing T cells by single-stranded DNA aptamers

    OpenAIRE

    Zhao, Nianxi; Pei, Sung-nan; Parekh, Parag; Salazar, Eric; Zu, Youli

    2014-01-01

    To investigate the potential clinical application of aptamers to prevention of HIV infection, single- stranded DNA (ssDNA) aptamers specific for CD4 were developed using the systematic evolution of ligands by exponential enrichment approach and next generation sequencing. In contrast to RNA-based aptamers, the developed ssDNA aptamers were stable in human serum up to 12 hr. Cell binding assays revealed that the aptamers specifically targeted CD4-expressing cells with high binding affinity (Kd...

  1. Medium Renewal Blocks Anti-Proliferative Effects of Metformin in Cultured MDA-MB-231 Breast Cancer Cells

    OpenAIRE

    Maruša Rajh; Klemen Dolinar; Katarina Miš; Mojca Pavlin; Sergej Pirkmajer

    2016-01-01

    Epidemiological studies indicate that metformin, a widely used type 2 diabetes drug, might reduce breast cancer risk and mortality in patients with type 2 diabetes. Metformin might protect against breast cancer indirectly by ameliorating systemic glucose homeostasis. Alternatively, it might target breast cancer cells directly. However, experiments using MDA-MB-231 cells, a standard in vitro breast cancer model, produced inconsistent results regarding effectiveness of metformin as a direct ant...

  2. Programmed Death-1 Antibody Blocks Therapeutic Effects of T-Regulatory Cells in Cockroach Antigen-Induced Allergic Asthma

    OpenAIRE

    McGee, Halvor S; Yagita, Hideo; Shao, Zhifei; Devendra K Agrawal

    2009-01-01

    We recently reported that the adoptive transfer of T-regulatory cells (Tregs) isolated from lung and spleen tissue of green fluorescent protein–transgenic mice reversed airway hyperresponsiveness and airway inflammation. Because Programmed Death-1 (PD-1) is a pivotal receptor regulating effector T-cell activation by Tregs, we evaluated whether PD-1 is involved in the therapeutic effect of naturally occurring Tregs (NTregs) and inducible Tregs (iTregs) in cockroach (CRA)-sensitized and challen...

  3. Hypoxia-induced soluble CD137 in malignant cells blocks CD137L-costimulation as an immune escape mechanism

    Science.gov (United States)

    Labiano, Sara; Palazón, Asis; Bolaños, Elixabet; Azpilikueta, Arantza; Sánchez-Paulete, Alfonso R.; Morales-Kastresana, Aizea; Quetglas, Jose I.; Perez-Gracia, José L.; Gúrpide, Alfonso; Rodriguez-Ruiz, Maria