Multidrug resistance and retroviral transduction potential in human small cell lung cancer cell lines

DEFF Research Database (Denmark)

Theilade, M D; Gram, G J; Jensen, P B

1999-01-01

Multidrug resistance (MDR) remains a major problem in the successful treatment of small cell lung cancer (SCLC). New treatment strategies are needed, such as gene therapy specifically targeting the MDR cells in the tumor. Retroviral LacZ gene-containing vectors that were either pseudotyped...... for the gibbon ape leukemia virus (GALV-1) receptor or had specificity for the amphotropic murine leukemia virus (MLV-A) receptor were used for transduction of five SCLC cell lines differing by a range of MDR mechanisms. Transduction efficiencies in these cell lines were compared by calculating the percentage...... of blue colonies after X-Gal staining of the cells grown in soft agar. All examined SCLC cell lines were transducible with either vector. Transduction efficiencies varied from 5.7% to 33.5% independent of the presence of MDR. These results indicate that MDR does not severely impair transduction of SCLC...

Queratinocitos humanos modificados genéticamente por medio de un vector retroviral

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C. Chamorro

2001-07-01

Full Text Available Los queratinocitos poseen características ideales para la terapia génica: accesibles, modifi-cables por vectores retrovirales, conservan in vitro sus propiedades de proliferación y diferen-ciación, fácil remoción por efectos adversos. Nuestro objetivo fue evaluar estas células comoblanco de transferencia de genes empleando el vector retroviral Foch-29 NeoR.

Cross-packaging of genetically distinct mouse and primate retroviral RNAs

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Jaballah Soumeya

2009-07-01

Full Text Available Abstract Background The mouse mammary tumor virus (MMTV is unique from other retroviruses in having multiple viral promoters, which can be regulated by hormones in a tissue specific manner. This unique property has lead to increased interest in studying MMTV replication with the hope of developing MMTV based vectors for human gene therapy. However, it has recently been reported that related as well as unrelated retroviruses can cross-package each other's genome raising safety concerns towards the use of candidate retroviral vectors for human gene therapy. Therefore, using a trans complementation assay, we looked at the ability of MMTV RNA to be cross-packaged and propagated by an unrelated primate Mason-Pfizer monkey virus (MPMV that has intracellular assembly process similar to that of MMTV. Results Our results revealed that MMTV and MPMV RNAs could be cross-packaged by the heterologous virus particles reciprocally suggesting that pseudotyping between two genetically distinct retroviruses can take place at the RNA level. However, the cross-packaged RNAs could not be propagated further indicating a block at post-packaging events in the retroviral life cycle. To further confirm that the specificity of cross-packaging was conferred by the packaging sequences (ψ, we cloned the packaging sequences of these viruses on expression plasmids that generated non-viral RNAs. Test of these non-viral RNAs confirmed that the reciprocal cross-packaging was primarily due to the recognition of ψ by the heterologous virus proteins. Conclusion The results presented in this study strongly argue that MPMV and MMTV are promiscuous in their ability to cross-package each other's genome suggesting potential RNA-protein interactions among divergent retroviral RNAs proposing that these interactions are more complicated than originally thought. Furthermore, these observations raise the possibility that MMTV and MPMV genomes could also co-package providing substrates for

Analyzing the Genotoxicity of Retroviral Vectors in Hematopoietic Cell Gene Therapy

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Luca Biasco

2018-03-01

Full Text Available Retroviral vectors, including those derived from gammaretroviruses and lentiviruses, have found their way into the clinical arena and demonstrated remarkable efficacy for the treatment of immunodeficiencies, leukodystrophies, and globinopathies. Despite these successes, gene therapy unfortunately also has had to face severe adverse events in the form of leukemias and myelodysplastic syndromes, related to the semi-random vector integration into the host cell genome that caused deregulation of neighboring proto-oncogenes. Although improvements in vector design clearly lowered the risk of this insertional mutagenesis, analysis of potential genotoxicity and the consequences of vector integration remain important parameters for basic and translational research and most importantly for the clinic. Here, we review current assays to analyze biodistribution and genotoxicity in the pre-clinical setting and describe tools to monitor vector integration sites in vector-treated patients as a biosafety readout.

Retroviral Vectors for Analysis of Viral Mutagenesis and Recombination

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Jonathan M.O. Rawson

2014-09-01

Full Text Available Retrovirus population diversity within infected hosts is commonly high due in part to elevated rates of replication, mutation, and recombination. This high genetic diversity often complicates the development of effective diagnostics, vaccines, and antiviral drugs. This review highlights the diverse vectors and approaches that have been used to examine mutation and recombination in retroviruses. Retroviral vectors for these purposes can broadly be divided into two categories: those that utilize reporter genes as mutation or recombination targets and those that utilize viral genes as targets of mutation or recombination. Reporter gene vectors greatly facilitate the detection, quantification, and characterization of mutants and/or recombinants, but may not fully recapitulate the patterns of mutagenesis or recombination observed in native viral gene sequences. In contrast, the detection of mutations or recombination events directly in viral genes is more biologically relevant but also typically more challenging and inefficient. We will highlight the advantages and disadvantages of the various vectors and approaches used as well as propose ways in which they could be improved.

Activities of wildtype and mutant p53 in suppression of homologous recombination as measured by a retroviral vector system

International Nuclear Information System (INIS)

Lu Xiongbin; Lozano, Guillermina; Donehower, Lawrence A.

2003-01-01

DNA repair of double strand breaks, interstrand DNA cross-links, and other types of DNA damage utilizes the processes of homologous recombination and non-homologous end joining to repair the damage. Aberrant homologous recombination is likely to be responsible for a significant fraction of chromosomal deletions, duplications, and translocations that are observed in cancer cells. To facilitate measurement of homologous recombination frequencies in normal cells, mutant cells, and cancer cells, we have developed a high titer retroviral vector containing tandem repeats of mutant versions of a GFP-Zeocin resistance fusion gene and an intact neomycin resistance marker. Recombination between the tandem repeats regenerates a functional GFP-Zeo R marker that can be easily scored. This retroviral vector was used to assess homologous recombination frequencies in human cancer cells and rodent fibroblasts with differing dosages of wild type or mutant p53. Absence of wild type p53 stimulated spontaneous and ionizing radiation-induced homologous recombination, confirming previous studies. Moreover, p53 +/- mouse fibroblasts show elevated levels of homologous recombination compared to their p53 +/+ counterparts following retroviral vector infection, indicating that p53 is haploinsufficient for suppression of homologous recombination. Transfection of vector-containing p53 null Saos-2 cells with various human cancer-associated p53 mutants revealed that these altered p53 proteins retain some recombination suppression function despite being totally inactive for transcriptional transactivation. The retroviral vector utilized in these studies may be useful in performing recombination assays on a wide array of cell types, including those not readily transfected by normal vectors

Cell-cell transmission of VSV-G pseudotyped lentivector particles.

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Amy M Skinner

Full Text Available Many replicating viruses, including HIV-1 and HTLV-1, are efficiently transmitted from the cell surface of actively infected cells upon contact with bystander cells. In a previous study, we reported the prolonged cell surface retention of VSV-G replication-deficient pseudotyped lentivector prior to endocytic entry. However, the competing kinetics of cell surface versus dissociation, neutralization or direct transfer to other cells have received comparatively little attention. Here we demonstrate that the relative efficiency of cell-cell surface transmission can outpace "cell-free" transduction at limiting vector input. This coincides with the prolonged half-life of cell bound vector but occurs, unlike HTLV-1, without evidence for particle aggregation. These studies suggest that cell-surface attachment stabilizes particles and alters neutralization kinetics. Our experiments provide novel insight into the underexplored cell-cell transmission of pseudotyped particles.

Murine leukemia virus-derived retroviral vector has differential integration patterns in human cell lines used to produce recombinant factor VIII

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Marcela Cristina Correa de Freitas

2014-06-01

Full Text Available OBJECTIVE: Nowadays recombinant factor VIII is produced in murine cells including in Chinese hamster ovary (CHO and baby hamster kidney cells (BHK. Previous studies, using the murine leukemia virus-derived retroviral vector pMFG-FVIII-P140K, modified two recombinant human cell lines, HepG2 and Hek293 to produce recombinant factor VIII. In order to characterize these cells, the present study aimed to analyze the integration pattern of retroviral vector pMFG-FVIII-P140K.METHODS: This study used ligation-mediated polymerase chain reaction to locate the site of viral vector integration by sequencing polymerase chain reaction products. The sequences were compared to genomic databases to characterize respective clones.RESULTS: The retroviral vector presented different and non-random profiles of integration between cells lines. A preference of integration for chromosomes 19, 17 and 11 was observed for HepG2FVIIIdB/P140K and chromosome 9 for Hek293FVIIIdB/P140K. In genomic regions such as CpG islands and transcription factor binding sites, there was no difference in the integration profiles for both cell lines. Integration in intronic regions of encoding protein genes (RefSeq genes was also observed in both cell lines. Twenty percent of integrations occurred at fragile sites in the genome of the HepG2 cell line and 17% in Hek293.CONCLUSION: The results suggest that the cell type can affect the profile of chromosomal integration of the retroviral vector used; these differences may interfere in the level of expression of recombinant proteins.

Genetic modification of hematopoietic cells using retroviral and lentiviral vectors: safety considerations for vector design and delivery into target cells.

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Dropulic, Boro

2005-07-01

The recent development of leukemia in three patients following retroviral vector gene transfer in hematopoietic stem cells, resulting in the death of one patient, has raised safety concerns for the use of integrating gene transfer vectors for human gene therapy. This review discusses these serious adverse events from the perspective of whether restrictions on vector design and vector-modified target cells are warranted at this time. A case is made against presently establishing specific restrictions for vector design and transduced cells; rather, their safety should be ascertained by empiric evaluation in appropriate preclinical models on a case-by-case basis. Such preclinical data, coupled with proper informed patient consent and a risk-benefit ratio analysis, provide the best available prospective evaluation of gene transfer vectors prior to their translation into the clinic.

Retroviral DNA Integration

Science.gov (United States)

2016-01-01

The integration of a DNA copy of the viral RNA genome into host chromatin is the defining step of retroviral replication. This enzymatic process is catalyzed by the virus-encoded integrase protein, which is conserved among retroviruses and LTR-retrotransposons. Retroviral integration proceeds via two integrase activities: 3′-processing of the viral DNA ends, followed by the strand transfer of the processed ends into host cell chromosomal DNA. Herein we review the molecular mechanism of retroviral DNA integration, with an emphasis on reaction chemistries and architectures of the nucleoprotein complexes involved. We additionally discuss the latest advances on anti-integrase drug development for the treatment of AIDS and the utility of integrating retroviral vectors in gene therapy applications. PMID:27198982

Targeted transgene insertion into the CHO cell genome using Cre recombinase-incorporating integrase-defective retroviral vectors.

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Kawabe, Yoshinori; Shimomura, Takuya; Huang, Shuohao; Imanishi, Suguru; Ito, Akira; Kamihira, Masamichi

2016-07-01

Retroviral vectors have served as efficient gene delivery tools in various biotechnology fields. However, viral DNA is randomly inserted into the genome, which can cause problems, such as insertional mutagenesis and gene silencing. Previously, we reported a site-specific gene integration system, in which a transgene is integrated into a predetermined chromosomal locus of Chinese hamster ovary (CHO) cells using integrase-defective retroviral vectors (IDRVs) and Cre recombinase. In this system, a Cre expression plasmid is transfected into founder cells before retroviral transduction. In practical applications of site-specific gene modification such as for hard-to-transfect cells or for in vivo gene delivery, both the transgene and the Cre protein into retroviral virions should be encapsulate. Here, we generated novel hybrid IDRVs in which viral genome and enzymatically active Cre can be delivered (Cre-IDRVs). Cre-IDRVs encoding marker genes, neomycin resistance and enhanced green fluorescent protein (EGFP), flanked by wild-type and mutated loxP sites were produced using an expression plasmid for a chimeric protein of Cre and retroviral gag-pol. After analyzing the incorporation of the Cre protein into retroviral virions by Western blotting, the Cre-IDRV was infected into founder CHO cells, in which marker genes (hygromycin resistance and red fluorescent protein) flanked with corresponding loxP sites are introduced into the genome. G418-resistant colonies expressing GFP appeared and the site-specific integration of the transgene into the expected chromosomal site was confirmed by PCR and sequencing of amplicons. Moreover, when Cre-IDRV carried a gene expression unit for a recombinant antibody, the recombinant cells in which the antibody expression cassette was integrated in a site-specific manner were generated and the cells produced the recombinant antibody. This method may provide a promising tool to perform site-specific gene modification according to Cre

Structural dynamics of retroviral genome and the packaging.

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Miyazaki, Yasuyuki; Miyake, Ariko; Nomaguchi, Masako; Adachi, Akio

2011-01-01

Retroviruses can cause diseases such as AIDS, leukemia, and tumors, but are also used as vectors for human gene therapy. All retroviruses, except foamy viruses, package two copies of unspliced genomic RNA into their progeny viruses. Understanding the molecular mechanisms of retroviral genome packaging will aid the design of new anti-retroviral drugs targeting the packaging process and improve the efficacy of retroviral vectors. Retroviral genomes have to be specifically recognized by the cognate nucleocapsid domain of the Gag polyprotein from among an excess of cellular and spliced viral mRNA. Extensive virological and structural studies have revealed how retroviral genomic RNA is selectively packaged into the viral particles. The genomic area responsible for the packaging is generally located in the 5' untranslated region (5' UTR), and contains dimerization site(s). Recent studies have shown that retroviral genome packaging is modulated by structural changes of RNA at the 5' UTR accompanied by the dimerization. In this review, we focus on three representative retroviruses, Moloney murine leukemia virus, human immunodeficiency virus type 1 and 2, and describe the molecular mechanism of retroviral genome packaging.

A stable murine-based RD114 retroviral packaging line efficiently transduces human hematopoietic cells.

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Ward, Maureen; Sattler, Rose; Grossman, I Robert; Bell, Anthony J; Skerrett, Donna; Baxi, Laxmi; Bank, Arthur

2003-11-01

Several barriers exist to high-efficiency transfer of therapeutic genes into human hematopoietic stem cells (HSCs) using complex oncoretroviral vectors. Human clinical trials to date have used Moloney leukemia virus-based amphotropic and gibbon ape leukemia virus-based envelopes in stable retroviral packaging lines. However, retroviruses pseudotyped with these envelopes have low titers due to the inability to concentrate viral supernatants efficiently by centrifugation without damaging the virus and low transduction efficiencies because of low-level expression of viral target receptors on human HSC. The RD114 envelope from the feline endogenous virus has been shown to transduce human CD34+ cells using transient packaging systems and to be concentrated to high titers by centrifugation. Stable packaging systems have potential advantages over transient systems because greater and more reproducible viral productions can be attained. We have, therefore, constructed and tested a stable RD114-expressing packaging line capable of high-level transduction of human CD34+ cells. Viral particles from this cell line were concentrated up to 100-fold (up to 10(7) viral particles/ml) by ultracentrifugation. Human hematopoietic progenitors from cord blood and sickle cell CD34+ cells were efficiently transduced with a Neo(R)-containing vector after a single exposure to concentrated RD114-pseudotyped virus produced from this cell line. Up to 78% of progenitors from transduced cord blood CD34+ cells and 51% of progenitors from sickle cell CD34+ cells expressed the NeoR gene. We also show transfer of a human beta-globin gene into progenitor cells from CD34+ cells from sickle cell patients with this new RD114 stable packaging system. The results indicate that this packaging line may eventually be useful in human clinical trials of globin gene therapy.

Structural dynamics of retroviral genome and the packaging

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Yasuyuki eMiyazaki

2011-12-01

Full Text Available Retroviruses can cause diseases such as AIDS, leukemia and tumors, but are also used as vectors for human gene therapy. All retroviruses, except foamy viruses, package two copies of unspliced genomic RNA into their progeny viruses. Understanding the molecular mechanisms of retroviral genome packaging will aid the design of new anti-retroviral drugs targeting the packaging process and improve the efficacy of retroviral vectors. Retroviral genomes have to be specifically recognized by the cognate nucleocapsid (NC domain of the Gag polyprotein from among an excess of cellular and spliced viral mRNA. Extensive virological and structural studies have revealed how retroviral genomic RNA is selectively packaged into the viral particles. The genomic area responsible for the packaging is generally located in the 5’ untranslated region (5’ UTR, and contains dimerization site(s. Recent studies have shown that retroviral genome packaging is modulated by structural changes of RNA at the 5’ UTR accompanied by the dimerization. In this review, we focus on three representative retroviruses, Moloney murine leukemia virus (MoMLV, human immunodeficiency virus type 1 (HIV-1 and 2 (HIV-2, and describe the molecular mechanism of retroviral genome packaging.

Murine Leukemia Virus (MLV)-based Coronavirus Spike-pseudotyped Particle Production and Infection

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Millet, Jean Kaoru; Whittaker, Gary R.

2016-01-01

Viral pseudotyped particles (pp) are enveloped virus particles, typically derived from retroviruses or rhabdoviruses, that harbor heterologous envelope glycoproteins on their surface and a genome lacking essential genes. These synthetic viral particles are safer surrogates of native viruses and acquire the tropism and host entry pathway characteristics governed by the heterologous envelope glycoprotein used. They have proven to be very useful tools used in research with many applications, such as enabling the study of entry pathways of enveloped viruses and to generate effective gene-delivery vectors. The basis for their generation lies in the capacity of some viruses, such as murine leukemia virus (MLV), to incorporate envelope glycoproteins of other viruses into a pseudotyped virus particle. These can be engineered to contain reporter genes such as luciferase, enabling quantification of virus entry events upon pseudotyped particle infection with susceptible cells. Here, we detail a protocol enabling generation of MLV-based pseudotyped particles, using the Middle East respiratory syndrome coronavirus (MERS-CoV) spike (S) as an example of a heterologous envelope glycoprotein to be incorporated. We also describe how these particles are used to infect susceptible cells and to perform a quantitative infectivity readout by a luciferase assay. PMID:28018942

Modulating ectopic gene expression levels by using retroviral vectors equipped with synthetic promoters.

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Ferreira, Joshua P; Peacock, Ryan W S; Lawhorn, Ingrid E B; Wang, Clifford L

2011-12-01

The human cytomegalovirus and elongation factor 1α promoters are constitutive promoters commonly employed by mammalian expression vectors. These promoters generally produce high levels of expression in many types of cells and tissues. To generate a library of synthetic promoters capable of generating a range of low, intermediate, and high expression levels, the TATA and CAAT box elements of these promoters were mutated. Other promoter variants were also generated by random mutagenesis. Evaluation using plasmid vectors integrated at a single site in the genome revealed that these various synthetic promoters were capable of expression levels spanning a 40-fold range. Retroviral vectors were equipped with the synthetic promoters and evaluated for their ability to reproduce the graded expression demonstrated by plasmid integration. A vector with a self-inactivating long terminal repeat could neither reproduce the full range of expression levels nor produce stable expression. Using a second vector design, the different synthetic promoters enabled stable expression over a broad range of expression levels in different cell lines. The online version of this article (doi:10.1007/s11693-011-9089-0) contains supplementary material, which is available to authorized users.

T-cell receptor transfer into human T cells with ecotropic retroviral vectors.

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Koste, L; Beissert, T; Hoff, H; Pretsch, L; Türeci, Ö; Sahin, U

2014-05-01

Adoptive T-cell transfer for cancer immunotherapy requires genetic modification of T cells with recombinant T-cell receptors (TCRs). Amphotropic retroviral vectors (RVs) used for TCR transduction for this purpose are considered safe in principle. Despite this, TCR-coding and packaging vectors could theoretically recombine to produce replication competent vectors (RCVs), and transduced T-cell preparations must be proven free of RCV. To eliminate the need for RCV testing, we transduced human T cells with ecotropic RVs so potential RCV would be non-infectious for human cells. We show that transfection of synthetic messenger RNA encoding murine cationic amino-acid transporter 1 (mCAT-1), the receptor for murine retroviruses, enables efficient transient ecotropic transduction of human T cells. mCAT-1-dependent transduction was more efficient than amphotropic transduction performed in parallel, and preferentially targeted naive T cells. Moreover, we demonstrate that ecotropic TCR transduction results in antigen-specific restimulation of primary human T cells. Thus, ecotropic RVs represent a versatile, safe and potent tool to prepare T cells for the adoptive transfer.

Complementation of a primer binding site-impaired murine leukemia virus-derived retroviral vector by a genetically engineered tRNA-like primer

DEFF Research Database (Denmark)

Lund, Anders Henrik; Duch, M; Lovmand, J

1997-01-01

, but not with a noncomplementary tRNA-like molecule. The engineered primer was shown to be involved in both the initiation of first-strand synthesis and second-strand transfer. These results provide an in vivo demonstration that the retroviral replication machinery may recognize sequence complementarity rather than actual primer...... binding site and 3' primer sequences. Use of mutated primer binding site vectors replicating via engineered primers may add additional control features to retroviral gene transfer technology....

Development and applications of VSV vectors based on cell tropism

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Hideki eTani

2012-01-01

Full Text Available Viral vectors have been available in various fields such as medical and biological research or gene therapy applications. Targeting vectors pseudotyped with distinct viral envelope proteins that influence cell tropism and transfection efficiency is a useful tool not only for examining entry mechanisms or cell tropisms but also for vaccine vector development. Vesicular stomatitis virus (VSV is an excellent candidate for development as a pseudotype vector. A recombinant VSV lacking its own envelope (G gene has been used to produce a pseudotype or recombinant VSV possessing the envelope proteins of heterologous viruses. These viruses possess a reporter gene instead of a VSV G gene in their genome, and therefore it is easy to evaluate their infectivity in the study of viral entry, including identification of viral receptors. Furthermore, advantage can be taken of a property of the pseudotype VSV, which is competence for single-round infection, in handling many different viruses that are either difficult to amplify in cultured cells or animals or that require specialized containment facilities. Here we describe procedures for producing pseudotype or recombinant VSVs and a few of the more prominent examples from among envelope viruses, such as hepatitis C virus, Japanese encephalitis virus, baculovirus, and hemorrhagic fever viruses.

Construction of retroviral recombinant containing human tissue ...

African Journals Online (AJOL)

USER

2010-03-29

Mar 29, 2010 ... Recombinant retroviral vector containing human tissue inhibitor of matrix metalloproteinase-2 (TIMP-2) gene was ..... heavy metal ions, the protein could be express in an .... involves adhesion, degradation and movement. To.

Retroviral packaging cells encapsulated in TheraCyte immunoisolation devices enable long-term in vivo gene delivery.

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Krupetsky, Anna; Parveen, Zahida; Marusich, Elena; Goodrich, Adrienne; Dornburg, Ralph

2003-05-01

The method of delivering a therapeutic gene into a patient is still one of the major obstacles towards successful human gene therapy. Here we describe a novel gene delivery approach using TheraCyte immunoisolation devices. Retroviral vector producing cells, derived from the avian retrovirus spleen necrosis virus, SNV, were encapsulated in TheraCyte devices and tested for the release of retroviral vectors. In vitro experiments show that such devices release infectious retroviral vectors into the tissue culture medium for up to 4 months. When such devices were implanted subcutaneously in SCID mice, infectious virus was released into the blood stream. There, the vectors were transported to and infected tumors, which had been induced by subcutaneous injection of tissue culture cells. Thus, this novel concept of a continuous, long-term gene delivery may constitute an attractive approach for future in vivo human gene therapy.

Construction and characterization in vitro of a bicistronic retroviral vector coding endostatin and interleukin-2 for use in gene therapy

International Nuclear Information System (INIS)

Calvo, Fernanda Bernardes

2009-01-01

Gene therapy has been used in preclinical studies and clinical trials in order to alleviate or cure a disease. Retroviral vectors are a tool for gene transfer is widely used. Bicistronic vectors are an attractive alternative for treatment of complex diseases. A variety of options exists to simultaneously express two genes in genetically modified cells. The most common approach relies on bicistronic vectors in which the genes are linked to each other by an internal ribosome entry site allowing co-translational expression of both cistrons. Endostatin, the C-terminal fragment of collagen XVIII, is a potent angiogenesis inhibitor. At present, ES has been widely used in anti-angiogenic in a variety of experimental tumor models, and clinical trials to test it as an anti-tumor agent are already under way. Immunotherapy has been used as adjuvant treatment for tumors and has been used in several preclinical studies and clinical trials. The objective of this project was to construct and characterize 'in vitro' an IRES-based bicistronic retroviral vector encoding endostatin and interleukin-2. The construction of the vector was performed in three stages, the final construction was analyzed by restriction analysis and sequencing. Packaging cells were prepared. The endostatin and interleukin-2 levels were determined by Dot blot. Monocistronic and bicistronic mRNA expression were analyzed by real time RT-PCR. Bicistronic vector showed high levels of virus trites, ranging from 4.20x10 5 to 1.53x10 6 UFC/ml. Secreted levels of endostatin and interleukin-2 ranged from 1.08 to 2.08μg/10 6 cells.24h and 0.66 - 0.89μg/10 6 cells.24h, respectively. The mRNA expression of ES in the NIH3T3 clone pLend-IRES-IL2SN was 2 times higher than the level presented by the NIH3T3 clone pLendSN. The endostatin promoted inhibition (40%) of endothelial cell proliferation. Interleukin-2 promoted a proliferation of 10.6% lymphocytes CD4 and 8.9% of CD8. We conclude that the IRES bicistronic vector

Study on constructing retroviral vector carrying HSV-tk gene and its antitumor effect in vitro

International Nuclear Information System (INIS)

Pan Yujun; Hui Guozhen; Hu Jin

1997-01-01

The author reports the construction of retroviral vector PLNTK carrying HsV-tk gene driven by pgk promoter and the successful transferring into cells NBA 2 and SHG 44 respectively as shown by PCR. In vitro study, HSV-tk-expressed-cells prove to be more sensitive to ACV than parent cells. The sensitivity of SHGLNTK and NBALNTK to ACV is 1000 and 500 times that of their parent cells respectively. 3 H-TdR test demonstrated that the DNA replication in gene modified cells is more suppressed than that of parent cells when treated with ACV. Moreover, the ACV sensitivity level of parent cells is enhanced when co-cultured with gene modified cells, which suggests the existence of the bystander effect

Complement inhibition enables tumor delivery of LCMV glycoprotein pseudotyped viruses in the presence of antiviral antibodies

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Laura Evgin

2016-01-01

Full Text Available The systemic delivery of therapeutic viruses, such as oncolytic viruses or vaccines, is limited by the generation of neutralizing antibodies. While pseudotyping of rhabdoviruses with the lymphocytic choriomeningitis virus glycoprotein has previously allowed for multiple rounds of delivery in mice, this strategy has not translated to other animal models. For the first time, we provide experimental evidence that antibodies generated against the lymphocytic choriomeningitis virus glycoprotein mediate robust complement-dependent viral neutralization via activation of the classical pathway. We show that this phenotype can be capitalized upon to deliver maraba virus pseudotyped with the lymphocytic choriomeningitis virus glycoprotein in a Fischer rat model in the face of neutralizing antibody through the use of complement modulators. This finding changes the understanding of the humoral immune response to arenaviruses, and also describes methodology to deliver viral vectors to their therapeutic sites of action without the interference of neutralizing antibody.

Characterization of an internal ribosomal entry segment within the 5' leader of avian reticuloendotheliosis virus type A RNA and development of novel MLV-REV-based retroviral vectors.

Science.gov (United States)

López-Lastra, M; Gabus, C; Darlix, J L

1997-11-01

The murine leukemia virus (MLV)-related type C viruses constitute a major class of retroviruses that includes numerous endogenous and exogenous mammalian viruses and the related avian spleen necrosis virus (SNV). The MLV-related viruses possess a long and multifunctional 5' untranslated leader involved in key steps of the viral life cycle--splicing, translation, RNA dimerization, encapsidation, and reverse transcription. Recent studies have shown that the 5' leader of Friend murine leukemia virus and Moloney murine leukemia virus can direct cap independent translation of gag precursor proteins (Berlioz et al., 1995; Vagner et al., 1995b). These data, together with structural homology studies (Koning et al., 1992), prompted us to undertake a search for new internal ribosome entry segment (IRES) of retroviral origin. Here we describe an IRES element within the 5' leader of avian reticuloendotheliosis virus type A (REV-A) genomic RNA. Data show that the REV-A 5' IRES element maps downstream of the packaging/dimerization (E/DLS) sequence (Watanabe and Temin, 1982; Darlix et al., 1992) and the minimal IRES sequence appears to be within a 129 nt fragment (nucleotides 452-580) of the 5' leader, immediately upstream of the gag AUG codon. The REV-A IRES has been successfully utilized in the construction of novel high titer MLV-based retroviral vectors, containing one or more IRES elements of retroviral origin. These retroviral constructs, which represent a starting point for the design of novel vectors suitable for gene therapy, are also of interest as a model system of internal translation initiation and its possible regulation during development, cancer, or virus infection.

Neutralization epitopes on HIV pseudotyped with HTLV-I: Conservation of carbohydrate Epitopes

DEFF Research Database (Denmark)

Sørensen, A M; Nielsen, C; Arendrup, M

1994-01-01

One mechanism for expanding the cellular tropism of human immunodeficiency virus (HIV) in vitro is through formation of phenotypically mixed particles (pseudotypes) with human T lymphotropic virus type I (HTLV-I). In this study we found that pseudotypes allow penetration of HIV particles into CD4......-negative cells, previously nonsusceptible to HIV infection. The infection of CD4-negative cells with pseudotypes could be blocked with anti-HTLV-I serum but failed to be significantly inhibited with anti-HIV serum or a V3-neutralizing anti-gp120 monoclonal antibody. This may represent a possibility...... by cell-free pseudotypes in CD4-negative cells. We suggest that although viral cofactors might expand the tropism of HIV in vivo, HIV and HTLV-I seem to induce common carbohydrate neutralization epitopes....

Neutralization epitopes on HIV pseudotyped with HTLV-I: conservation of carbohydrate epitopes

DEFF Research Database (Denmark)

Sørensen, A M; Nielsen, C; Arendrup, M

1994-01-01

One mechanism for expanding the cellular tropism of human immunodeficiency virus (HIV) in vitro is through formation of phenotypically mixed particles (pseudotypes) with human T lymphotropic virus type I (HTLV-I). In this study we found that pseudotypes allow penetration of HIV particles into CD4......-negative cells, previously nonsusceptible to HIV infection. The infection of CD4-negative cells with pseudotypes could be blocked with anti-HTLV-I serum but failed to be significantly inhibited with anti-HIV serum or a V3-neutralizing anti-gp120 monoclonal antibody. This may represent a possibility...... by cell-free pseudotypes in CD4-negative cells. We suggest that although viral cofactors might expand the tropism of HIV in vivo, HIV and HTLV-I seem to induce common carbohydrate neutralization epitopes....

Functional cloning using pFB retroviral cDNA expression libraries.

Science.gov (United States)

Felts, Katherine A; Chen, Keith; Zaharee, Kim; Sundar, Latha; Limjoco, Jamie; Miller, Anna; Vaillancourt, Peter

2002-09-01

Retroviral cDNA expression libraries allow the efficient introduction of complex cDNA libraries into virtually any mitotic cell type for screening based on gene function. The cDNA copy number per cell can be easily controlled by adjusting the multiplicity of infection, thus cell populations may be generated in which >90% of infected cells contain one to three cDNAs. We describe the isolation of two known oncogenes and one cell-surface receptor from a human Burkitt's lymphoma (Daudi) cDNA library inserted into the high-titer retroviral vector pFB.

Sindbis Virus-Pseudotyped Lentiviral Vectors Carrying VEGFR2-Specific Nanobody for Potential Transductional Targeting of Tumor Vasculature.

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Ahani, Roshank; Roohvand, Farzin; Cohan, Reza Ahangari; Etemadzadeh, Mohammad Hossein; Mohajel, Nasir; Behdani, Mahdi; Shahosseini, Zahra; Madani, Navid; Azadmanesh, Kayhan

2016-11-01

Introduction of selectivity/specificity into viral-based gene delivery systems, such as lentiviral vectors (LVs), is crucial in their systemic administration for cancer gene therapy. The pivotal role of tumor-associated endothelial cells (TAECs) in tumor angiogenesis and overexpression of vascular endothelial growth factor receptor-2 (VEGFR2 or KDR) in TAECs makes them a potent target in cancer treatment. Herein, we report the development of VEGFR2-targeted LVs pseudotyped with chimeric sindbis virus E2 glycoprotein (cSVE2s). For this purpose, either sequence of a VEGFR2-specific nanobody or its natural ligand (VEGF 121 ) was inserted into the binding site of sindbis virus E2 glycoprotein. In silico modeling data suggested that the inserted targeting motifs were exposed in the context of cSVE2s. Western blot analysis of LVs indicated the incorporation of cSVE2s into viral particles. Capture ELISA demonstrated the specificity/functionality of the incorporated cSVE2s. Transduction of 293/KDR (expressing VEGFR2) or 293T cells (negative control) by constructed LVs followed by fluorescent microscopy and flow cytometric analyses indicated selective transduction of 293/KDR cells (30 %) by both targeting motifs compared to 293T control cells (1-2 %). These results implied similar targeting properties of VEGFR2-specific nanobody compared to the VEGF 121 and indicated the potential for transductional targeting of tumor vasculature by the nanobody displaying LVs.

An adeno-associated viral vector transduces the rat hypothalamus and amygdala more efficient than a lentiviral vector

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Vreugdenhil Erno

2010-07-01

Full Text Available Abstract Background This study compared the transduction efficiencies of an adeno-associated viral (AAV vector, which was pseudotyped with an AAV1 capsid and encoded the green fluorescent protein (GFP, with a lentiviral (LV vector, which was pseudotyped with a VSV-G envelop and encoded the discosoma red fluorescent protein (dsRed, to investigate which viral vector transduced the lateral hypothalamus or the amygdala more efficiently. The LV-dsRed and AAV1-GFP vector were mixed and injected into the lateral hypothalamus or into the amygdala of adult rats. The titers that were injected were 1 × 108 or 1 × 109 genomic copies of AAV1-GFP and 1 × 105 transducing units of LV-dsRed. Results Immunostaining for GFP and dsRed showed that AAV1-GFP transduced significantly more cells than LV-dsRed in both the lateral hypothalamus and the amygdala. In addition, the number of LV particles that were injected can not easily be increased, while the number of AAV1 particles can be increased easily with a factor 100 to 1000. Both viral vectors appear to predominantly transduce neurons. Conclusions This study showed that AAV1 vectors are better tools to overexpress or knockdown genes in the lateral hypothalamus and amygdala of adult rats, since more cells can be transduced with AAV1 than with LV vectors and the titer of AAV1 vectors can easily be increased to transduce the area of interest.

Follistatin allows efficient retroviral-mediated gene transfer into rat liver

International Nuclear Information System (INIS)

Borgnon, Josephine; Djamouri, Fatima; Lorand, Isabelle; Rico, Virginie Di; Loux, Nathalie; Pages, Jean-Christophe; Franco, Dominique; Capron, Frederique; Weber, Anne

2005-01-01

Retroviral vectors are widely used tools for gene therapy. However, in vivo gene transfer is only effective in dividing cells, which, in liver, requires a regenerative stimulus. Follistatin is effective in promoting liver regeneration after 90% and 70% hepatectomy in rats. We studied its efficacy on liver regeneration and retroviral-mediated gene delivery in 50% hepatectomized rats. When human recombinant follistatin was infused into the portal vein immediately after 50% hepatectomy, hepatocyte proliferation was significantly higher than in control 50% hepatectomized rats. A single injection of virus particles administered 23 h after follistatin infusion resulted in more than 20% gene transduction efficiency in hepatocytes compared to 3% in control rats. It is concluded that a single injection of follistatin induces onset of proliferation in 50% hepatectomized rats and allows efficient retroviral-mediated gene transfer to the liver

Differential diagnosis of feline leukemia virus subgroups using pseudotype viruses expressing green fluorescent protein.

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Nakamura, Megumi; Sato, Eiji; Miura, Tomoyuki; Baba, Kenji; Shimoda, Tetsuya; Miyazawa, Takayuki

2010-06-01

Feline leukemia virus (FeLV) is classified into three receptor interference subgroups, A, B and C. In this study, to differentiate FeLV subgroups, we developed a simple assay system using pseudotype viruses expressing green fluorescent protein (GFP). We prepared gfp pseudotype viruses, named gfp(FeLV-A), gfp(FeLV-B) and gfp(FeLV-C) harboring envelopes of FeLV-A, B and C, respectively. The gfp pseudotype viruses completely interfered with the same subgroups of FeLV reference strains on FEA cells (a feline embryonic fibroblast cell line). We also confirmed that the pseudotype viruses could differentiate FeLV subgroups in field isolates. The assay will be useful for differential diagnosis of FeLV subgroups in veterinary diagnostic laboratories in the future.

Lentiviral Vector Gene Transfer to Porcine Airways

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Patrick L Sinn

2012-01-01

Full Text Available In this study, we investigated lentiviral vector development and transduction efficiencies in well-differentiated primary cultures of pig airway epithelia (PAE and wild-type pigs in vivo. We noted gene transfer efficiencies similar to that observed for human airway epithelia (HAE. Interestingly, feline immunodeficiency virus (FIV-based vectors transduced immortalized pig cells as well as pig primary cells more efficiently than HIV-1–based vectors. PAE express TRIM5α, a well-characterized species-specific lentiviral restriction factor. We contrasted the restrictive properties of porcine TRIM5α against FIV- and HIV-based vectors using gain and loss of function approaches. We observed no effect on HIV-1 or FIV conferred transgene expression in response to porcine TRIM5α overexpression or knockdown. To evaluate the ability of GP64-FIV to transduce porcine airways in vivo, we delivered vector expressing mCherry to the tracheal lobe of the lung and the ethmoid sinus of 4-week-old pigs. One week later, epithelial cells expressing mCherry were readily detected. Our findings indicate that pseudotyped FIV vectors confer similar tropisms in porcine epithelia as observed in human HAE and provide further support for the selection of GP64 as an appropriate envelope pseudotype for future preclinical gene therapy studies in the porcine model of cystic fibrosis (CF.

Construction and characterization in vitro of a bicistronic retroviral vector coding endostatin and interleukin-2 for use in gene therapy; Construcao e caracterizacao in vitro de um vetor retroviral bicistronico codificando endostatina e interleucina-2 para utilizacao em terapia genica

Energy Technology Data Exchange (ETDEWEB)

Calvo, Fernanda Bernardes

2009-07-01

Gene therapy has been used in preclinical studies and clinical trials in order to alleviate or cure a disease. Retroviral vectors are a tool for gene transfer is widely used. Bicistronic vectors are an attractive alternative for treatment of complex diseases. A variety of options exists to simultaneously express two genes in genetically modified cells. The most common approach relies on bicistronic vectors in which the genes are linked to each other by an internal ribosome entry site allowing co-translational expression of both cistrons. Endostatin, the C-terminal fragment of collagen XVIII, is a potent angiogenesis inhibitor. At present, ES has been widely used in anti-angiogenic in a variety of experimental tumor models, and clinical trials to test it as an anti-tumor agent are already under way. Immunotherapy has been used as adjuvant treatment for tumors and has been used in several preclinical studies and clinical trials. The objective of this project was to construct and characterize 'in vitro' an IRES-based bicistronic retroviral vector encoding endostatin and interleukin-2. The construction of the vector was performed in three stages, the final construction was analyzed by restriction analysis and sequencing. Packaging cells were prepared. The endostatin and interleukin-2 levels were determined by Dot blot. Monocistronic and bicistronic mRNA expression were analyzed by real time RT-PCR. Bicistronic vector showed high levels of virus trites, ranging from 4.20x10{sup 5} to 1.53x10{sup 6}UFC/ml. Secreted levels of endostatin and interleukin-2 ranged from 1.08 to 2.08{mu}g/10{sup 6}cells.24h and 0.66 - 0.89{mu}g/10{sup 6}cells.24h, respectively. The mRNA expression of ES in the NIH3T3 clone pLend-IRES-IL2SN was 2 times higher than the level presented by the NIH3T3 clone pLendSN. The endostatin promoted inhibition (40%) of endothelial cell proliferation. Interleukin-2 promoted a proliferation of 10.6% lymphocytes CD4 and 8.9% of CD8. We conclude that

Prospects for Foamy Viral Vector Anti-HIV Gene Therapy

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Arun K. Nalla

2016-03-01

Full Text Available Stem cell gene therapy approaches for Human Immunodeficiency Virus (HIV infection have been explored in clinical trials and several anti-HIV genes delivered by retroviral vectors were shown to block HIV replication. However, gammaretroviral and lentiviral based retroviral vectors have limitations for delivery of anti-HIV genes into hematopoietic stem cells (HSC. Foamy virus vectors have several advantages including efficient delivery of transgenes into HSC in large animal models, and a potentially safer integration profile. This review focuses on novel anti-HIV transgenes and the potential of foamy virus vectors for HSC gene therapy of HIV.

Retroviral DNA integration: ASLV, HIV, and MLV show distinct target site preferences.

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Rick S Mitchell

2004-08-01

Full Text Available The completion of the human genome sequence has made possible genome-wide studies of retroviral DNA integration. Here we report an analysis of 3,127 integration site sequences from human cells. We compared retroviral vectors derived from human immunodeficiency virus (HIV, avian sarcoma-leukosis virus (ASLV, and murine leukemia virus (MLV. Effects of gene activity on integration targeting were assessed by transcriptional profiling of infected cells. Integration by HIV vectors, analyzed in two primary cell types and several cell lines, strongly favored active genes. An analysis of the effects of tissue-specific transcription showed that it resulted in tissue-specific integration targeting by HIV, though the effect was quantitatively modest. Chromosomal regions rich in expressed genes were favored for HIV integration, but these regions were found to be interleaved with unfavorable regions at CpG islands. MLV vectors showed a strong bias in favor of integration near transcription start sites, as reported previously. ASLV vectors showed only a weak preference for active genes and no preference for transcription start regions. Thus, each of the three retroviruses studied showed unique integration site preferences, suggesting that virus-specific binding of integration complexes to chromatin features likely guides site selection.

Expression of cDNAs in human Natural Killer cell lines by retroviral transduction.

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Miah, S M Shahjahan; Campbell, Kerry S

2010-01-01

Human NK-like cell lines are difficult to transfect using standard mammalian expression vectors and conventional transfection protocols, but they are susceptible to retroviral transduction as a means to introduce cDNAs. Our laboratory has exploited this technique to study a number of receptors in human NK cell lines. The method utilizes a bicistronic retroviral vector that co-expresses either drug resistance or enhanced green fluorescent protein (EGFP) in parallel with the gene of interest. After a single infection with recombinant retrovirus, transduced NK cells can be sorted for expression of EGFP or the transduced cell surface marker. Alternatively, cells expressing the transduced cDNAs can be selected for by treatment with neomycin, puromycin, or hygromycin. Using this method, the sorted/selected cells uniformly express the gene of interest and the expression is stable for many weeks of culture.

Mouse Mammary Tumor Virus Promoter-Containing Retroviral Promoter Conversion Vectors for Gene-Directed Enzyme Prodrug Therapy are Functional in Vitro and in Vivo

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Reinhard Klein

2008-01-01

Full Text Available Gene directed-enzyme prodrug therapy (GDEPT is an approach for sensitization of tumor cells to an enzymatically activated, otherwise nontoxic, prodrug. Cytochrome P450 2B1 (CYP2B1 metabolizes the prodrugs cyclophosphamide (CPA and ifosfamide (IFA to produce the cytotoxic substances phosphoramide mustard and isophosphoramide mustard as well as the byproduct acrolein. We have constructed a retroviral promoter conversion (ProCon vector for breast cancer GDEPT. The vector allows expression of CYP2B1 from the mouse mammary tumor virus (MMTV promoter known to be active in the mammary glands of transgenic animals. It is anticipated to be used for the generation of encapsulated viral vector producing cells which, when placed inside or close to a tumor, will act as suppliers of the therapeutic CYP2B1 protein as well as of the therapeutic vector itself. The generated vector was effectively packaged by virus producing cells and allowed the production of high levels of enzymatically active CYP2B1 in infected cells which sensitized them to killing upon treatment with both IFA and CPA. Determination of the respective IC50 values demonstrated that the effective IFA dose was reduced by sixteen folds. Infection efficiencies in vivo were determined using a reporter gene-bearing vector in a mammary cancer cell-derived xenograft tumor mouse model.

Effective in vivo and ex vivo gene transfer to intestinal mucosa by VSV-G-pseudotyped lentiviral vectors

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Kasahara Noriyuki

2010-05-01

Full Text Available Abstract Background Gene transfer to the gastrointestinal (GI mucosa is a therapeutic strategy which could prove particularly advantageous for treatment of various hereditary and acquired intestinal disorders, including inflammatory bowel disease (IBD, GI infections, and cancer. Methods We evaluated vesicular stomatitis virus glycoprotein envelope (VSV-G-pseudotyped lentiviral vectors (LV for efficacy of gene transfer to both murine rectosigmoid colon in vivo and human colon explants ex vivo. LV encoding beta-galactosidase (LV-β-Gal or firefly-luciferase (LV-fLuc reporter genes were administered by intrarectal instillation in mice, or applied topically for ex vivo transduction of human colorectal explant tissues from normal individuals. Macroscopic and histological evaluations were performed to assess any tissue damage or inflammation. Transduction efficiency and systemic biodistribution were evaluated by real-time quantitative PCR. LV-fLuc expression was evaluated by ex vivo bioluminescence imaging. LV-β-Gal expression and identity of transduced cell types were examined by histochemical and immunofluorescence staining. Results Imaging studies showed positive fLuc signals in murine distal colon; β-Gal-positive cells were found in both murine and human intestinal tissue. In the murine model, β-Gal-positive epithelial and lamina propria cells were found to express cytokeratin, CD45, and CD4. LV-transduced β-Gal-positive cells were also seen in human colorectal explants, consisting mainly of CD45, CD4, and CD11c-positive cells confined to the LP. Conclusions We have demonstrated the feasibility of LV-mediated gene transfer into colonic mucosa. We also identified differential patterns of mucosal gene transfer dependent on whether murine or human tissue was used. Within the limitations of the study, the LV did not appear to induce mucosal damage and were not distributed beyond the distal colon.

RD-MolPack technology for the constitutive production of self-inactivating lentiviral vectors pseudotyped with the nontoxic RD114-TR envelope.

Science.gov (United States)

Marin, Virna; Stornaiuolo, Anna; Piovan, Claudia; Corna, Stefano; Bossi, Sergio; Pema, Monika; Giuliani, Erica; Scavullo, Cinzia; Zucchelli, Eleonora; Bordignon, Claudio; Rizzardi, Gian Paolo; Bovolenta, Chiara

2016-01-01

To date, gene therapy with transiently derived lentivectors has been very successful to cure rare infant genetic diseases. However, transient manufacturing is unfeasible to treat adult malignancies because large vector lots are required. By contrast, stable manufacturing is the best option for high-incidence diseases since it reduces the production cost, which is the major current limitation to scale up the transient methods. We have previously developed the proprietary RD2-MolPack technology for the stable production of second-generation lentivectors, based on the RD114-TR envelope. Of note, opposite to vesicular stomatitis virus glycoprotein (VSV-G) envelope, RD114-TR does not need inducible expression thanks to lack of toxicity. Here, we present the construction of RD2- and RD3-MolPack cells for the production of self-inactivating lentivectors expressing green fluorescent protein (GFP) as a proof-of-concept of the feasibility and safety of this technology before its later therapeutic exploitation. We report that human T lymphocytes transduced with self-inactivating lentivectors derived from RD3-MolPack cells or with self-inactivating VSV-G pseudotyped lentivectors derived from transient transfection show identical T-cell memory differentiation phenotype and comparable transduction efficiency in all T-cell subsets. RD-MolPack technology represents, therefore, a straightforward tool to simplify and standardize lentivector manufacturing to engineer T-cells for frontline immunotherapy applications.

The endogenous retroviral insertion in the human complement C4 gene modulates the expression of homologous genes by antisense inhibition.

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Schneider, P M; Witzel-Schlömp, K; Rittner, C; Zhang, L

2001-02-01

Intron 9 contains the complete endogenous retrovirus HERV-K(C4) as a 6.4-kb insertion in 60% of human C4 genes. The retroviral insertion is in reverse orientation to the C4 coding sequence. Therefore, expression of C4 could lead to the transcription of an antisense RNA, which might protect against exogenous retroviral infections. To test this hypothesis, open reading frames from the HERV sequence were subcloned in sense orientiation into a vector allowing expression of a beta-galactosidase fusion protein. Mouse L cells which had been stably transfected with either the human C4A or C4B gene both carrying the HERV insertion (LC4 cells), and L(Tk-) cells without the C4 gene were transiently transfected either with a retroviral construct or with the wild-type vector. Expression was monitored using an enzymatic assay. We demonstrated that (1) HERV-K(C4) antisense mRNA transcripts are present in cells constitutively expressing C4, (2) expression of retroviral-like constructs is significantly downregulated in cells expressing C4, and (3) this downregulation is further modulated in a dose-dependent fashion following interferon-gamma stimulation of C4 expression. These results support the hypothesis of a genomic antisense strategy mediated by the HERV-K(C4) insertion as a possible defense mechanism against exogenous retroviral infections.

Quantification of Lyssavirus-Neutralizing Antibodies Using Vesicular Stomatitis Virus Pseudotype Particles.

Science.gov (United States)

Moeschler, Sarah; Locher, Samira; Conzelmann, Karl-Klaus; Krämer, Beate; Zimmer, Gert

2016-09-16

Rabies is a highly fatal zoonotic disease which is primarily caused by rabies virus (RABV) although other members of the genus Lyssavirus can cause rabies as well. As yet, 14 serologically and genetically diverse lyssaviruses have been identified, mostly in bats. To assess the quality of rabies vaccines and immunoglobulin preparations, virus neutralization tests with live RABV are performed in accordance with enhanced biosafety standards. In the present work, a novel neutralization test is presented which takes advantage of a modified vesicular stomatitis virus (VSV) from which the glycoprotein G gene has been deleted and replaced by reporter genes. This single-cycle virus was trans-complemented with RABV envelope glycoprotein. Neutralization of this pseudotype virus with RABV reference serum or immune sera from vaccinated mice showed a strong correlation with the rapid fluorescent focus inhibition test (RFFIT). Importantly, pseudotype viruses containing the envelope glycoproteins of other lyssaviruses were neutralized by reference serum to a significantly lesser extent or were not neutralized at all. Taken together, a pseudotype virus system has been successfully developed which allows the safe, fast, and sensitive detection of neutralizing antibodies directed against different lyssaviruses.

Quantification of Lyssavirus-Neutralizing Antibodies Using Vesicular Stomatitis Virus Pseudotype Particles

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Sarah Moeschler

2016-09-01

Full Text Available Rabies is a highly fatal zoonotic disease which is primarily caused by rabies virus (RABV although other members of the genus Lyssavirus can cause rabies as well. As yet, 14 serologically and genetically diverse lyssaviruses have been identified, mostly in bats. To assess the quality of rabies vaccines and immunoglobulin preparations, virus neutralization tests with live RABV are performed in accordance with enhanced biosafety standards. In the present work, a novel neutralization test is presented which takes advantage of a modified vesicular stomatitis virus (VSV from which the glycoprotein G gene has been deleted and replaced by reporter genes. This single-cycle virus was trans-complemented with RABV envelope glycoprotein. Neutralization of this pseudotype virus with RABV reference serum or immune sera from vaccinated mice showed a strong correlation with the rapid fluorescent focus inhibition test (RFFIT. Importantly, pseudotype viruses containing the envelope glycoproteins of other lyssaviruses were neutralized by reference serum to a significantly lesser extent or were not neutralized at all. Taken together, a pseudotype virus system has been successfully developed which allows the safe, fast, and sensitive detection of neutralizing antibodies directed against different lyssaviruses.

A comparison of foamy and lentiviral vector genotoxicity in SCID-repopulating cells shows foamy vectors are less prone to clonal dominance

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Elizabeth M Everson

2016-01-01

Full Text Available Hematopoietic stem cell (HSC gene therapy using retroviral vectors has immense potential, but vector-mediated genotoxicity limits use in the clinic. Lentiviral vectors are less genotoxic than gammaretroviral vectors and have become the vector of choice in clinical trials. Foamy retroviral vectors have a promising integration profile and are less prone to read-through transcription than gammaretroviral or lentiviral vectors. Here, we directly compared the safety and efficacy of foamy vectors to lentiviral vectors in human CD34+ repopulating cells in immunodeficient mice. To increase their genotoxic potential, foamy and lentiviral vectors with identical transgene cassettes with a known genotoxic spleen focus forming virus promoter were used. Both vectors resulted in efficient marking in vivo and a total of 825 foamy and 460 lentiviral vector unique integration sites were recovered in repopulating cells 19 weeks after transplantation. Foamy vector proviruses were observed less often near RefSeq gene and proto-oncogene transcription start sites than lentiviral vectors. The foamy vector group were also more polyclonal with fewer dominant clones (two out of six mice than the lentiviral vector group (eight out of eight mice, and only lentiviral vectors had integrants near known proto-oncogenes in dominant clones. Our data further support the relative safety of foamy vectors for HSC gene therapy.

Cross- and Co-Packaging of Retroviral RNAs and Their Consequences

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Lizna M. Ali

2016-10-01

Full Text Available Retroviruses belong to the family Retroviridae and are ribonucleoprotein (RNP particles that contain a dimeric RNA genome. Retroviral particle assembly is a complex process, and how the virus is able to recognize and specifically capture the genomic RNA (gRNA among millions of other cellular and spliced retroviral RNAs has been the subject of extensive investigation over the last two decades. The specificity towards RNA packaging requires higher order interactions of the retroviral gRNA with the structural Gag proteins. Moreover, several retroviruses have been shown to have the ability to cross-/co-package gRNA from other retroviruses, despite little sequence homology. This review will compare the determinants of gRNA encapsidation among different retroviruses, followed by an examination of our current understanding of the interaction between diverse viral genomes and heterologous proteins, leading to their cross-/co-packaging. Retroviruses are well-known serious animal and human pathogens, and such a cross-/co-packaging phenomenon could result in the generation of novel viral variants with unknown pathogenic potential. At the same time, however, an enhanced understanding of the molecular mechanisms involved in these specific interactions makes retroviruses an attractive target for anti-viral drugs, vaccines, and vectors for human gene therapy.

Forced recombination of psi-modified murine leukaemia virus-based vectors with murine leukaemia-like and VL30 murine endogenous retroviruses

DEFF Research Database (Denmark)

Mikkelsen, J G; Lund, Anders Henrik; Duch, M

1999-01-01

Co-encapsidation of retroviral RNAs into virus particles allows for the generation of recombinant proviruses through events of template switching during reverse transcription. By use of a forced recombination system based on recombinational rescue of replication- defective primer binding site-imp....... We note that recombination-based rescue of primer binding site knock-out retroviral vectors may constitute a sensitive assay to register putative genetic interactions involving endogenous retroviral RNAs present in cells of various species.......-impaired Akv-MLV-derived vectors, we here examine putative genetic interactions between vector RNAs and copackaged endogenous retroviral RNAs of the murine leukaemia virus (MLV) and VL30 retroelement families. We show (i) that MLV recombination is not blocked by nonhomology within the 5' untranslated region...... harbouring the supposed RNA dimer-forming cis -elements and (ii) that copackaged retroviral RNAs can recombine despite pronounced sequence dissimilarity at the cross-over site(s) and within parts of the genome involved in RNA dimerization, encapsidation and strand transferring during reverse transcription...

Analysis of proteins of mouse sarcoma pseudotype viruses: type-specific radioimmunoassays for ecotropic virus p30's

International Nuclear Information System (INIS)

Kennel, S.J.; Tennant, R.W.

1979-01-01

Murine sarcoma virus pseudotypes were prepared by infection of nonproducer cells (A1-2), which were transformed by the Gazdar strain of mouse sarcoma virus, with Gross (N-tropic), WN1802B (B-tropic), or Moloney (NB-tropic) viruses. The respective host range pseudotype sarcoma viruses were defined by the tritration characteristics on cells with the appropriate Fv-1 genotype. Proteins from virus progeny were analyzed by sodium dodecyl sulfate--polyacrylamide gel electrophoresis. Bands present in both the 65,000- and the 10,000- to 20,000-molecular-weight regions of the gel distinguished the pseudotype viruses from their respective helpers. Furthermore, two protein bands were noted in the p30 region of murine sarcoma virus (Gross), one corresponding to Gross virus p30, and another of slightly slower mobility. However, since the mobility of the putative sarcoma p30 is nearly indentical to that of WN1802B, its presence could not be established by sodium dodecyl sulfate--polyacrylamide gel electrophoresis. Type-specific radioimmunossays for Gross virus p30 and for WN1802B p30 were applied for analysis of pseudotype preparations, and among several ecotropic viruses tested, only the homologous virus scored in the respective assay. By use of these assays, pseudotype viruses were found to contain only 8 to 48% helper-specific p30's; the remainder is presumably derived from the sarcoma virus

A Functional Henipavirus Envelope Glycoprotein Pseudotyped Lentivirus Assay System

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Broder Christopher C

2010-11-01

Full Text Available Abstract Background Hendra virus (HeV and Nipah virus (NiV are newly emerged zoonotic paramyxoviruses discovered during outbreaks in Queensland, Australia in 1994 and peninsular Malaysia in 1998/9 respectively and classified within the new Henipavirus genus. Both viruses can infect a broad range of mammalian species causing severe and often-lethal disease in humans and animals, and repeated outbreaks continue to occur. Extensive laboratory studies on the host cell infection stage of HeV and NiV and the roles of their envelope glycoproteins have been hampered by their highly pathogenic nature and restriction to biosafety level-4 (BSL-4 containment. To circumvent this problem, we have developed a henipavirus envelope glycoprotein pseudotyped lentivirus assay system using either a luciferase gene or green fluorescent protein (GFP gene encoding human immunodeficiency virus type-1 (HIV-1 genome in conjunction with the HeV and NiV fusion (F and attachment (G glycoproteins. Results Functional retrovirus particles pseudotyped with henipavirus F and G glycoproteins displayed proper target cell tropism and entry and infection was dependent on the presence of the HeV and NiV receptors ephrinB2 or B3 on target cells. The functional specificity of the assay was confirmed by the lack of reporter-gene signals when particles bearing either only the F or only G glycoprotein were prepared and assayed. Virus entry could be specifically blocked when infection was carried out in the presence of a fusion inhibiting C-terminal heptad (HR-2 peptide, a well-characterized, cross-reactive, neutralizing human mAb specific for the henipavirus G glycoprotein, and soluble ephrinB2 and B3 receptors. In addition, the utility of the assay was also demonstrated by an examination of the influence of the cytoplasmic tail of F in its fusion activity and incorporation into pseudotyped virus particles by generating and testing a panel of truncation mutants of NiV and HeV F

Production of glycosylated physiologically normal human α1-antitrypsin by mouse fibroblasts modified by insertion of a human α1-antitrypsin cDNA using a retroviral vector

International Nuclear Information System (INIS)

Garver, R.I. Jr.; Chytil, A.; Karlsson, S.

1987-01-01

α 2 -Antitrypsin (α 1 AT) deficiency is a hereditary disorder characterized by reduced serum levels of α 1 AT, resulting in destruction of the lower respiratory tract by neutrophil elastase. As an approach to augment α 1 AT levels in this disorder with physiologically normal human α 1 AT, the authors have integrated a full-length normal human α 1 AT cDNA into the genome of mouse fibroblasts. To accomplish this, the retroviral vector N2 was modified by inserting the simian virus 40 early promoter followed by the α 1 AT cDNA. Southern analysis demonstrated that the intact cDNA was present in the genome of selected clones of the transfected murine fibroblasts psi2 and infected NIH 3T3. The clones produced three mRNA transcripts containing human α 1 AT sequences, secreted an α 1 AT molecule recognized by an anti-human α 1 AT antibody, with the same molecular mass as normal human α 1 AT and that complexed with and inhibited human neutrophil elastase. The psi2 produced α 1 AT was glycosylated, and when infused intravenously into mice, it had a serum half-life similar to normal α 1 AT purified from human plasma and markedly longer than that of nonglycosylated human α 1 AT cDNA-directed yeast-produced α 1 AT. These studies demonstrate the feasibility of using a retroviral vector to insert the normal human α 1 AT cDNA into non-α 1 AT-producing cells, resulting in the synthesis and secretion of physiologically normal α 1 AT

Characterization of Ebola Virus Entry by Using Pseudotyped Viruses: Identification of Receptor-Deficient Cell Lines

OpenAIRE

Wool-Lewis, Rouven J.; Bates, Paul

1998-01-01

Studies analyzing Ebola virus replication have been severely hampered by the extreme pathogenicity of this virus. To permit analysis of the host range and function of the Ebola virus glycoprotein (Ebo-GP), we have developed a system for pseudotyping these glycoproteins into murine leukemia virus (MLV). This pseudotyped virus, MLV(Ebola), can be readily concentrated to titers which exceed 5 × 106 infectious units/ml and is effectively neutralized by antibodies specific for Ebo-GP. Analysis of ...

Immunogenicity and efficacy of immunodeficiency virus-like particles pseudotyped with the G protein of vesicular stomatitis virus

International Nuclear Information System (INIS)

Kuate, Seraphin; Stahl-Hennig, Christiane; Stoiber, Heribert; Nchinda, Godwin; Floto, Anja; Franz, Monika; Sauermann, Ulrike; Bredl, Simon; Deml, Ludwig; Ignatius, Ralf; Norley, Steve; Racz, Paul; Tenner-Racz, Klara; Steinman, Ralph M.; Wagner, Ralf; Uberla, Klaus

2006-01-01

Vaccination with exogenous antigens such as recombinant viral proteins, immunodeficiency virus-derived whole inactivated virus particles, or virus-like particles (VLP) has generally failed to provide sufficient protection in animal models for AIDS. Pseudotyping VLPs with the vesicular stomatitis virus G protein (VSV-G), which is known to mediate entry into dendritic cells, might allow more efficient stimulation of immune responses. Therefore, we pseudotyped noninfectious immunodeficiency virus-like particles with VSV-G and carried out a preliminary screen of their immunogenicity and vaccination efficacy. Incorporation of VSV-G into HIV-1 VLPs led to hundred-fold higher antibody titers to HIV-1 Gag and enhancement of T cell responses in mice. Repeated vaccination of rhesus monkeys for 65 weeks with VSV-G pseudotyped simian immunodeficiency virus (SIV)-like particles (VLP[G]) provided initial evidence for efficient suppression of viral load after mucosal challenge with the SIVmac239 virus. Challenge of monkeys after a 28 week vaccination regimen with VLP[G] led to a reduction in peak viremia, but persistent suppression of viral load was not achieved. Due to limitations in the number of animals available for this study, improved efficacy of VSV-G pseudotyped VLPs in nonhuman primates could not be demonstrated. However, mouse experiments revealed that pseudotyping of VLPs with fusion-competent VSV-G clearly improves their immunogenicity. Additional strategies, particularly adjuvants, should be considered to provide greater protection against a challenge with pathogenic immunodeficiency virus

Efficient generation of fully reprogrammed human iPS cells via polycistronic retroviral vector and a new cocktail of chemical compounds.

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Zhonghui Zhang

Full Text Available Direct reprogramming of human somatic cells into induced pluripotent stem (iPS cells by defined transcription factors (TFs provides great potential for regenerative medicine and biomedical research. This procedure has many challenges, including low reprogramming efficiency, many partially reprogrammed colonies, somatic coding mutations in the genome, etc. Here, we describe a simple approach for generating fully reprogrammed human iPS cells by using a single polycistronic retroviral vector expressing four human TFs in a single open reading frame (ORF, combined with a cocktail containing three small molecules (Sodium butyrate, SB431542, and PD0325901. Our results demonstrate that human iPS cells generated by this approach express human ES cells markers and exhibit pluripotency demonstrated by their abilities to differentiate into the three germ layers in vitro and in vivo. Notably, this approach not only provides a much faster reprogramming process but also significantly diminishes partially reprogrammed iPS cell colonies, thus facilitating efficient isolation of desired fully reprogrammed iPS cell colonies.

Protection of hematopoietic cells from O(6)-alkylation damage by O(6)-methylguanine DNA methyltransferase gene transfer: studies with different O(6)-alkylating agents and retroviral backbones.

Science.gov (United States)

Jansen, M; Bardenheuer, W; Sorg, U R; Seeber, S; Flasshove, M; Moritz, T

2001-07-01

Overexpression of O(6)-methylguanine DNA methyltransferase (MGMT) can protect hematopoietic cells from O(6)-alkylation damage. To identify possible clinical applications of this technology we compared the effect of MGMT gene transfer on the hematotoxicity induced by different O(6)-alkylating agents in clinical use: the chloroethylnitrosoureas ACNU, BCNU, CCNU and the tetrazine derivative temozolomide. In addition, various retroviral vectors expressing the MGMT-cDNA were investigated to identify optimal viral backbones for hematoprotection by MGMT expression. Protection from ACNU, BCNU, CCNU or temozolomide toxicity was evaluated utilizing a Moloney murine leukemia virus-based retroviral vector (N2/Zip-PGK-MGMT) to transduce primary murine bone marrow cells. Increased resistance in murine colony-forming units (CFU) was demonstrated for all four drugs. In comparison to mock-transduced controls, after transduction with N2/Zip-PGK-MGMT the IC50 for CFU increased on average 4.7-fold for ACNU, 2.5-fold for BCNU, 6.3-fold for CCNU and 1.5-fold for temozolomide. To study the effect of the retroviral backbone on hematoprotection various vectors expressing the human MGMT-cDNA from a murine embryonic sarcoma virus LTR (MSCV-MGMT) or a hybrid spleen focus-forming/murine embryonic sarcoma virus LTR (SF1-MGMT) were compared with the N2/Zip-PGK-MGMT vector. While all vectors increased resistance of transduced human CFU to ACNU, the SF1-MGMT construct was most efficient especially at high ACNU concentrations (8-12 microg/ml). Similar results were obtained for protection of murine high-proliferative-potential colony-forming cells. These data may help to optimize treatment design and retroviral constructs in future clinical studies aiming at hematoprotection by MGMT gene transfer.

Immune responses to transgene and retroviral vector in patients treated with ex vivo-engineered T cells

NARCIS (Netherlands)

Lamers, C.H.; Willemsen, R.; Elzakker, P. van; Steenbergen-Langeveld, S. van; Broertjes, M.; Oosterwijk-Wakka, J.C.; Oosterwijk, E.; Sleijfer, S.; Debets, R.; Gratama, J.W.

2011-01-01

Adoptive transfer of immune effector cells that are gene modified by retroviral transduction to express tumor-specific receptors constitutes an attractive approach to treat cancer. In patients with metastatic renal cell carcinoma, we performed a study with autologous T cells genetically retargeted

Characterization of Ebola virus entry by using pseudotyped viruses: identification of receptor-deficient cell lines.

Science.gov (United States)

Wool-Lewis, R J; Bates, P

1998-04-01

Studies analyzing Ebola virus replication have been severely hampered by the extreme pathogenicity of this virus. To permit analysis of the host range and function of the Ebola virus glycoprotein (Ebo-GP), we have developed a system for pseudotyping these glycoproteins into murine leukemia virus (MLV). This pseudotyped virus, MLV(Ebola), can be readily concentrated to titers which exceed 5 x 10(6) infectious units/ml and is effectively neutralized by antibodies specific for Ebo-GP. Analysis of MLV(Ebola) infection revealed that the host range conferred by Ebo-GP is very broad, extending to cells of a variety of species. Notably, all lymphoid cell lines tested were completely resistant to infection; we speculate that this is due to the absence of a cellular receptor for Ebo-GP on B and T cells. The generation of high-titer MLV(Ebola) pseudotypes will be useful for the analysis of immune responses to Ebola virus infection, development of neutralizing antibodies, analysis of glycoprotein function, and isolation of the cellular receptor(s) for the Ebola virus.

Transgenic mice produced by retroviral transduction of male germ-line stem cells

OpenAIRE

Nagano, Makoto; Brinster, Clayton J.; Orwig, Kyle E.; Ryu, Buom-Yong; Avarbock, Mary R.; Brinster, Ralph L.

2001-01-01

Male germ-line stem cells are the only cell type in postnatal mammals that have the capability to self-renew and to contribute genes to the next generation. Genetic modification of these cells would provide an opportunity to study the biology of their complex self-renewal and differentiation processes, as well as enable the generation of transgenic animals in a wide range of species. Although retroviral vectors have been used as an efficient method to introduce genes into a variety of cell ty...

Gene therapy for adenosine deaminase-deficient severe combined immune deficiency: clinical comparison of retroviral vectors and treatment plans.

Science.gov (United States)

Candotti, Fabio; Shaw, Kit L; Muul, Linda; Carbonaro, Denise; Sokolic, Robert; Choi, Christopher; Schurman, Shepherd H; Garabedian, Elizabeth; Kesserwan, Chimene; Jagadeesh, G Jayashree; Fu, Pei-Yu; Gschweng, Eric; Cooper, Aaron; Tisdale, John F; Weinberg, Kenneth I; Crooks, Gay M; Kapoor, Neena; Shah, Ami; Abdel-Azim, Hisham; Yu, Xiao-Jin; Smogorzewska, Monika; Wayne, Alan S; Rosenblatt, Howard M; Davis, Carla M; Hanson, Celine; Rishi, Radha G; Wang, Xiaoyan; Gjertson, David; Yang, Otto O; Balamurugan, Arumugam; Bauer, Gerhard; Ireland, Joanna A; Engel, Barbara C; Podsakoff, Gregory M; Hershfield, Michael S; Blaese, R Michael; Parkman, Robertson; Kohn, Donald B

2012-11-01

We conducted a gene therapy trial in 10 patients with adenosine deaminase (ADA)-deficient severe combined immunodeficiency using 2 slightly different retroviral vectors for the transduction of patients' bone marrow CD34(+) cells. Four subjects were treated without pretransplantation cytoreduction and remained on ADA enzyme-replacement therapy (ERT) throughout the procedure. Only transient (months), low-level (< 0.01%) gene marking was observed in PBMCs of 2 older subjects (15 and 20 years of age), whereas some gene marking of PBMC has persisted for the past 9 years in 2 younger subjects (4 and 6 years). Six additional subjects were treated using the same gene transfer protocol, but after withdrawal of ERT and administration of low-dose busulfan (65-90 mg/m(2)). Three of these remain well, off ERT (5, 4, and 3 years postprocedure), with gene marking in PBMC of 1%-10%, and ADA enzyme expression in PBMC near or in the normal range. Two subjects were restarted on ERT because of poor gene marking and immune recovery, and one had a subsequent allogeneic hematopoietic stem cell transplantation. These studies directly demonstrate the importance of providing nonmyeloablative pretransplantation conditioning to achieve therapeutic benefits with gene therapy for ADA-deficient severe combined immunodeficiency.

Gene therapy for adenosine deaminase–deficient severe combined immune deficiency: clinical comparison of retroviral vectors and treatment plans

Science.gov (United States)

Candotti, Fabio; Shaw, Kit L.; Muul, Linda; Carbonaro, Denise; Sokolic, Robert; Choi, Christopher; Schurman, Shepherd H.; Garabedian, Elizabeth; Kesserwan, Chimene; Jagadeesh, G. Jayashree; Fu, Pei-Yu; Gschweng, Eric; Cooper, Aaron; Tisdale, John F.; Weinberg, Kenneth I.; Crooks, Gay M.; Kapoor, Neena; Shah, Ami; Abdel-Azim, Hisham; Yu, Xiao-Jin; Smogorzewska, Monika; Wayne, Alan S.; Rosenblatt, Howard M.; Davis, Carla M.; Hanson, Celine; Rishi, Radha G.; Wang, Xiaoyan; Gjertson, David; Yang, Otto O.; Balamurugan, Arumugam; Bauer, Gerhard; Ireland, Joanna A.; Engel, Barbara C.; Podsakoff, Gregory M.; Hershfield, Michael S.; Blaese, R. Michael; Parkman, Robertson

2012-01-01

We conducted a gene therapy trial in 10 patients with adenosine deaminase (ADA)–deficient severe combined immunodeficiency using 2 slightly different retroviral vectors for the transduction of patients' bone marrow CD34+ cells. Four subjects were treated without pretransplantation cytoreduction and remained on ADA enzyme-replacement therapy (ERT) throughout the procedure. Only transient (months), low-level (< 0.01%) gene marking was observed in PBMCs of 2 older subjects (15 and 20 years of age), whereas some gene marking of PBMC has persisted for the past 9 years in 2 younger subjects (4 and 6 years). Six additional subjects were treated using the same gene transfer protocol, but after withdrawal of ERT and administration of low-dose busulfan (65-90 mg/m2). Three of these remain well, off ERT (5, 4, and 3 years postprocedure), with gene marking in PBMC of 1%-10%, and ADA enzyme expression in PBMC near or in the normal range. Two subjects were restarted on ERT because of poor gene marking and immune recovery, and one had a subsequent allogeneic hematopoietic stem cell transplantation. These studies directly demonstrate the importance of providing nonmyeloablative pretransplantation conditioning to achieve therapeutic benefits with gene therapy for ADA-deficient severe combined immunodeficiency. PMID:22968453

Viral vectors for cystic fibrosis gene therapy: What does the future hold?

Directory of Open Access Journals (Sweden)

Uta Griesenbach

2010-12-01

Full Text Available Uta Griesenbach1, Makoto Inoue2, Mamoru Hasegawa2, Eric WFW Alton11Department of Gene Therapy, Imperial College London, UK; The UK Cystic Fibrosis Gene Therapy Consortium; 2DNAVEC Corporation, Tsukuba, JapanAbstract: Gene transfer to the airway epithelium has been more difficult than originally anticipated, largely because of significant extra- and intracellular barriers in the lung. In general, viral vectors are more adapted to overcoming these barriers than nonviral gene transfer agents and are, therefore, more efficient in transferring genes into recipient cells. Viral vectors derived from adenovirus, adeno-associated virus, and Sendai virus, which all have a natural tropism for the airway epithelium, have been evaluated for cystic fibrosis (CF gene therapy. Although these vectors transduce airway epithelial cells efficiently, gene expression is transient and repeated administration is inefficient. They are, therefore, unlikely to be suitable for CF gene therapy. More recently, lentiviruses (LV have been assessed for lung gene transfer. In contrast to retroviruses, they transduce nondividing cells and randomly integrate into the genome. However, LVs do not have a natural tropism for the lung, and a significant amount of effort has been put into pseudotyping these vectors with proteins suitable for airway gene transfer. Several studies have shown that LV-mediated transduction leads to persistent gene expression (for the lifetime of the animal in the airways and, importantly, repeated administration is feasible. Thus, appropriately pseudotyped LV vectors are promising candidates for CF gene therapy. Here, we will review preclinical and clinical research related to viral CF gene therapy.Keywords: cystic fibrosis, gene therapy, adenovirus, AAV, lentivirus, Sendai virus

Queratinocitos derivados de piel humana modificados por el vector retroviral FOCH 29-NeoR

Directory of Open Access Journals (Sweden)

Luz Marina Restrepo

2000-02-01

Full Text Available

En este protocolo se evaluará la eficiencia de la transducción mediada por el vector retroviral FOCH 29-NeoR derivado del virus de Friend; éste ha mostrado una alta eficiencia en la transducción, tanto de células madres hematopoyéticas como de otras líneas celulares. Se medirá su eficiencia de transducción en cultivos primarios de queratinocitos, derivados de biopsias de piel humana o de sobrantes de procedimientos quirúrgicos como circuncisiones, mastectomías y cirugía cosmética de pacientes que consultan el Hospital Universitario San Vicente de Paul, Hospital la María, la Clínica del Rosario y la Clínica León XIII.

Las muestras de piel se procesarán en un lapso no superior a 12 horas, se eliminará el exceso de dermis y tejido conectivo por digestión con dispasa (0.6-2.4 U/ml a 37°C durante 1 hora. Las muestras serán lavadas con PBS, antibiótico (penicilina + estreptomicina y se cortarán en fragmentos de 1-2 mm; después de 2-3 horas de digestión con tripsina-EDTA (0.25% las células serán resuspendidas en KGM (Medio de crecimiento para queratinocitos y se sembrarán a una concentración de 105 - 3x105 células por plato de 100 mm; se incubarán a 37°C, 5% CO2 con cambios de medio 2-3 veces por semana. Se harán subcultivos con el fin de expandirlos y congelar una parte de las

Characterization of retrovirus-based reporter viruses pseudotyped with the precursor membrane and envelope glycoproteins of four serotypes of dengue viruses

International Nuclear Information System (INIS)

Hu, H.-P.; Hsieh, S.-C.; King, C.-C.; Wang, W.-K.

2007-01-01

In this study, we successfully established retrovirus-based reporter viruses pseudotyped with the precursor membrane and envelope (PrM/E) proteins of each of the four serotypes of dengue viruses, which caused the most important arboviral diseases in this century. Co-sedimentation of the dengue E protein and HIV-1 core proteins by sucrose gradient analysis of the pseudotype reporter virus of dengue virus type 2, D2(HIVluc), and detection of HIV-1 core proteins by immunoprecipitation with anti-E monoclonal antibody suggested that dengue viral proteins were incorporated into the pseudotype viral particles. The infectivity in target cells, as assessed by the luciferase activity, can be inhibited by the lysosomotropic agents, suggesting a pH-dependent mechanism of entry. Amino acid substitutions of the leucine at position 107, a critical residue at the fusion loop of E protein, with lysine resulted in severe impairment in infectivity, suggesting that entry of the pseudotype reporter virus is mediated through the fusogenic properties of E protein. With more and more dengue viral sequences available from different outbreaks worldwide, this sensitive and convenient tool has the potential to facilitate molecular characterization of the PrM/E proteins of dengue field isolates

New windows into retroviral RNA structures.

Science.gov (United States)

Jayaraman, Dhivya; Kenyon, Julia Claire

2018-01-25

The multiple roles of both viral and cellular RNAs have become increasingly apparent in recent years, and techniques to model them have become significantly more powerful, enabling faster and more accurate visualization of RNA structures. Techniques such as SHAPE (selective 2'OH acylation analysed by primer extension) have revolutionized the field, and have been used to examine RNAs belonging to many and diverse retroviruses. Secondary structure probing reagents such as these have been aided by the development of faster methods of analysis either via capillary or next-generation sequencing, allowing the analysis of entire genomes, and of retroviral RNA structures within virions. Techniques to model the three-dimensional structures of these large RNAs have also recently developed. The flexibility of retroviral RNAs, both structural and functional, is clear from the results of these new experimental techniques. Retroviral RNA structures and structural changes control many stages of the lifecycle, and both the RNA structures themselves and their interactions with ligands are potential new drug targets. In addition, our growing understanding of retroviral RNA structures is aiding our knowledge of cellular RNA form and function.

Rapid transcriptional pulsing dynamics of high expressing retroviral transgenes in embryonic stem cells.

Directory of Open Access Journals (Sweden)

Mandy Y M Lo

Full Text Available Single cell imaging studies suggest that transcription is not continuous and occurs as discrete pulses of gene activity. To study mechanisms by which retroviral transgenes can transcribe to high levels, we used the MS2 system to visualize transcriptional dynamics of high expressing proviral integration sites in embryonic stem (ES cells. We established two ES cell lines each bearing a single copy, self-inactivating retroviral vector with a strong ubiquitous human EF1α gene promoter directing expression of mRFP fused to an MS2-stem-loop array. Transfection of MS2-EGFP generated EGFP focal dots bound to the mRFP-MS2 stem loop mRNA. These transcription foci colocalized with the transgene integration site detected by immunoFISH. Live tracking of single cells for 20 minutes detected EGFP focal dots that displayed frequent and rapid fluctuations in transcription over periods as short as 25 seconds. Similarly rapid fluctuations were detected from focal doublet signals that colocalized with replicated proviral integration sites by immunoFISH, consistent with transcriptional pulses from sister chromatids. We concluded that retroviral transgenes experience rapid transcriptional pulses in clonal ES cell lines that exhibit high level expression. These events are directed by a constitutive housekeeping gene promoter and may provide precedence for rapid transcriptional pulsing at endogenous genes in mammalian stem cells.

Retroviral-mediated transfer and expression of human β-globin genes in cultured murine and human erythroid cells

International Nuclear Information System (INIS)

Weber-Benarous, A.; Cone, R.D.; London, I.M.; Mulligan, R.C.

1988-01-01

The authors cloned human β-globin DNA sequences from a genomic library prepared from DNA isolated from the human leukemia cell line K562 and have used the retroviral vector pZip-NeoSV(X)1 to introduce a 3.0-kilobase segment encompassing the globin gene into mouse erythroleukemia cells. Whereas the endogenous K562 β-globin gene is repressed in K562 cells, when introduced into mouse erythroleukemia cells by retroviral-mediated gene transfer, the β-globin gene from K562 cells was transcribed and induced 5-20-fold after treatment of the cells with dimethyl sulfoxide. The transcripts were correctly initiated, and expression and regulation of the K562 gene were identical to the expression of a normal human β-globin gene transferred into mouse erythroleukemia cells in the same way. They have also introduced the normal human β-globin gene into K562 cells using the same retrovirus vector. SP6 analysis of the RNA isolated from the transduced cells showed that the normal β-globin gene was transcribed at a moderately high level, before or after treatment with hemin. Based on these data, they suggest that the lack of expression of the endogenous β-globin gene in K562 cells does not result from an alteration in the gene itself and may not result from a lack of factor(s) necessary for β-lobin gene transcription. Retroviral-mediated transfer of the human β-globin gene may, however, uniquely influence expression of the gene K562 cells

Identification of an internal ribosome entry segment in the 5' region of the mouse VL30 retrotransposon and its use in the development of retroviral vectors.

Science.gov (United States)

López-Lastra, M; Ulrici, S; Gabus, C; Darlix, J L

1999-10-01

Mouse virus-like 30S RNAs (VL30m) constitute a family of retrotransposons, present at 100 to 200 copies, dispersed in the mouse genome. They display little sequence homology to Moloney murine leukemia virus (MoMLV), do not encode virus-like proteins, and have not been implicated in retroviral carcinogenesis. However, VL30 RNAs are efficiently packaged into MLV particles that are propagated in cell culture. In this study, we addressed whether the 5' region of VL30m could replace the 5' leader of MoMLV functionally in a recombinant vector construct. Our data confirm that the putative packaging sequence of VL30 is located within the 5' region (nucleotides 362 to 1149 with respect to the cap structure) and that it can replace the packaging sequence of MoMLV. We also show that VL30m contains an internal ribosome entry segment (IRES) in the 5' region, as do MoMLV, Friend murine leukemia virus, Harvey murine sarcoma virus, and avian reticuloendotheliosis virus type A. Our data show that both the packaging and IRES functions of the 5' region of VL30m RNA can be efficiently used to develop retrotransposon-based vectors.

Regulation of human heme oxygenase in endothelial cells by using sense and antisense retroviral constructs.

Science.gov (United States)

Quan, S; Yang, L; Abraham, N G; Kappas, A

2001-10-09

Our objective was to determine whether overexpression and underexpression of human heme oxygenase (HHO)-1 could be controlled on a long-term basis by introduction of the HO-1 gene in sense (S) and antisense (AS) orientation with an appropriate vector into endothelial cells. Retroviral vector (LXSN) containing viral long terminal repeat promoter-driven human HO-1 S (LSN-HHO-1) and LXSN vectors containing HHO-1 promoter (HOP)-controlled HHO-1 S and AS (LSN-HOP-HHO-1 and LSN-HOP-HHO-1-AS) sequences were constructed and used to transfect rat lung microvessel endothelial cells (RLMV cells) and human dermal microvessel endothelial cells (HMEC-1 cells). RLMV cells transduced with HHO-1 S expressed human HO-1 mRNA and HO-1 protein associated with elevation in total HO activity compared with nontransduced cells. Vector-mediated expression of HHO-1 S or AS under control of HOP resulted in effective production of HO-1 or blocked induction of endogenous human HO-1 in HMEC-1 cells, respectively. Overexpression of HO-1 AS was associated with a long-term decrease (45%) of endogenous HO-1 protein and an increase (167%) in unmetabolized exogenous heme in HMEC-1 cells. Carbon monoxide (CO) production in HO-1 S- or AS-transduced HMEC-1 cells after heme treatment was increased (159%) or decreased (50%), respectively, compared with nontransduced cells. HO-2 protein levels did not change. These findings demonstrate that HHO-1 S and AS retroviral constructs are functional in enhancing and reducing HO activity, respectively, and thus can be used to regulate cellular heme levels, the activity of heme-dependent enzymes, and the rate of heme catabolism to CO and bilirubin.

Amplification and chromosomal dispersion of human endogenous retroviral sequences

International Nuclear Information System (INIS)

Steele, P.E.; Martin, M.A.; Rabson, A.B.; Bryan, T.; O'Brien, S.J.

1986-01-01

Endogenous retroviral sequences have undergone amplification events involving both viral and flanking cellular sequences. The authors cloned members of an amplified family of full-length endogenous retroviral sequences. Genomic blotting, employing a flanking cellular DNA probe derived from a member of this family, revealed a similar array of reactive bands in both humans and chimpanzees, indicating that an amplification event involving retroviral and associated cellular DNA sequences occurred before the evolutionary separation of these two primates. Southern analyses of restricted somatic cell hybrid DNA preparations suggested that endogenous retroviral segments are widely dispersed in the human genome and that amplification and dispersion events may be linked

Mobilization of endogenous retroviruses in mice after infection with an exogenous retrovirus.

Science.gov (United States)

Evans, Leonard H; Alamgir, A S M; Owens, Nick; Weber, Nick; Virtaneva, Kimmo; Barbian, Kent; Babar, Amenah; Malik, Frank; Rosenke, Kyle

2009-03-01

Mammalian genomes harbor a large number of retroviral elements acquired as germ line insertions during evolution. Although many of the endogenous retroviruses are defective, several contain one or more intact viral genes that are expressed under certain physiological or pathological conditions. This is true of the endogenous polytropic retroviruses that generate recombinant polytropic murine leukemia viruses (MuLVs). In these recombinants the env gene sequences of exogenous ecotropic MuLVs are replaced with env gene sequences from an endogenous polytropic retrovirus. Although replication-competent endogenous polytropic retroviruses have not been observed, the recombinant polytropic viruses are capable of replicating in numerous species. Recombination occurs during reverse transcription of a virion RNA heterodimer comprised of an RNA transcript from an endogenous polytropic virus and an RNA transcript from an exogenous ecotropic MuLV RNA. It is possible that homodimers corresponding to two full-length endogenous RNA genomes are also packaged. Thus, infection by an exogenous virus may result not only in recombination with endogenous sequences, but also in the mobilization of complete endogenous retrovirus genomes via pseudotyping within exogenous retroviral virions. We report that the infection of mice with an ecotropic virus results in pseudotyping of intact endogenous viruses that have not undergone recombination. The endogenous retroviruses infect and are integrated into target cell genomes and subsequently replicate and spread as pseudotyped viruses. The mobilization of endogenous retroviruses upon infection with an exogenous retrovirus may represent a major interaction of exogenous retroviruses with endogenous retroviruses and may have profound effects on the pathogenicity of retroviral infections.

Adherence to anti-retroviral drugs in pregnant and lactating HIV ...

African Journals Online (AJOL)

Background: Anti-retroviral drugs reduce morbidity and mortality due to HIV and prevent transmission from mother to child. But compliance on anti-retroviral treatment is an essential element for the success of therapeutic goals. Objective: To assess the level of compliance of anti-retroviral treatment in pregnant and lactating ...

High-definition mapping of retroviral integration sites defines the fate of allogeneic T cells after donor lymphocyte infusion.

Directory of Open Access Journals (Sweden)

Claudia Cattoglio

2010-12-01

Full Text Available The infusion of donor lymphocytes transduced with a retroviral vector expressing the HSV-TK suicide gene in patients undergoing hematopoietic stem cell transplantation for leukemia/lymphoma promotes immune reconstitution and prevents infections and graft-versus-host disease. Analysis of the clonal dynamics of genetically modified lymphocytes in vivo is of crucial importance to understand the potential genotoxic risk of this therapeutic approach. We used linear amplification-mediated PCR and pyrosequencing to build a genome-wide, high-definition map of retroviral integration sites in the genome of peripheral blood T cells from two different donors and used gene expression profiling and bioinformatics to associate integration clusters to transcriptional activity and to genetic and epigenetic features of the T cell genome. Comparison with matched random controls and with integrations obtained from CD34(+ hematopoietic stem/progenitor cells showed that integration clusters occur within chromatin regions bearing epigenetic marks associated with active promoters and regulatory elements in a cell-specific fashion. Analysis of integration sites in T cells obtained ex vivo two months after infusion showed no evidence of integration-related clonal expansion or dominance, but rather loss of cells harboring integration events interfering with RNA post-transcriptional processing. The study shows that high-definition maps of retroviral integration sites are a powerful tool to analyze the fate of genetically modified T cells in patients and the biological consequences of retroviral transduction.

Anti-retroviral therapy induced diabetes in a Nigerian | Bakari ...

African Journals Online (AJOL)

African Health Sciences ... Background:Anti-retroviral therapy (ART) using Highly Active Anti-retroviral Therapy (HAART) has led to ... HIV infected individuals on one hand, and side effects of chronic administration of these drugs on the other.

Integration Site and Clonal Expansion in Human Chronic Retroviral Infection and Gene Therapy

Science.gov (United States)

Niederer, Heather A.; Bangham, Charles R. M.

2014-01-01

Retroviral vectors have been successfully used therapeutically to restore expression of genes in a range of single-gene diseases, including several primary immunodeficiency disorders. Although clinical trials have shown remarkable results, there have also been a number of severe adverse events involving malignant outgrowth of a transformed clonal population. This clonal expansion is influenced by the integration site profile of the viral integrase, the transgene expressed, and the effect of the viral promoters on the neighbouring host genome. Infection with the pathogenic human retrovirus HTLV-1 also causes clonal expansion of cells containing an integrated HTLV-1 provirus. Although the majority of HTLV-1-infected people remain asymptomatic, up to 5% develop an aggressive T cell malignancy. In this review we discuss recent findings on the role of the genomic integration site in determining the clonality and the potential for malignant transformation of cells carrying integrated HTLV-1 or gene therapy vectors, and how these results have contributed to the understanding of HTLV-1 pathogenesis and to improvements in gene therapy vector safety. PMID:25365582

Identification of an Internal Ribosome Entry Segment in the 5′ Region of the Mouse VL30 Retrotransposon and Its Use in the Development of Retroviral Vectors

Science.gov (United States)

López-Lastra, Marcelo; Ulrici, Sandrine; Gabus, Caroline; Darlix, Jean-Luc

1999-01-01

Mouse virus-like 30S RNAs (VL30m) constitute a family of retrotransposons, present at 100 to 200 copies, dispersed in the mouse genome. They display little sequence homology to Moloney murine leukemia virus (MoMLV), do not encode virus-like proteins, and have not been implicated in retroviral carcinogenesis. However, VL30 RNAs are efficiently packaged into MLV particles that are propagated in cell culture. In this study, we addressed whether the 5′ region of VL30m could replace the 5′ leader of MoMLV functionally in a recombinant vector construct. Our data confirm that the putative packaging sequence of VL30 is located within the 5′ region (nucleotides 362 to 1149 with respect to the cap structure) and that it can replace the packaging sequence of MoMLV. We also show that VL30m contains an internal ribosome entry segment (IRES) in the 5′ region, as do MoMLV, Friend murine leukemia virus, Harvey murine sarcoma virus, and avian reticuloendotheliosis virus type A. Our data show that both the packaging and IRES functions of the 5′ region of VL30m RNA can be efficiently used to develop retrotransposon-based vectors. PMID:10482590

Tropism-Modification Strategies for Targeted Gene Delivery Using Adenoviral Vectors

Directory of Open Access Journals (Sweden)

Andrew H. Baker

2010-10-01

Full Text Available Achieving high efficiency, targeted gene delivery with adenoviral vectors is a long-standing goal in the field of clinical gene therapy. To achieve this, platform vectors must combine efficient retargeting strategies with detargeting modifications to ablate native receptor binding (i.e. CAR/integrins/heparan sulfate proteoglycans and “bridging” interactions. “Bridging” interactions refer to coagulation factor binding, namely coagulation factor X (FX, which bridges hepatocyte transduction in vivo through engagement with surface expressed heparan sulfate proteoglycans (HSPGs. These interactions can contribute to the off-target sequestration of Ad5 in the liver and its characteristic dose-limiting hepatotoxicity, thereby significantly limiting the in vivo targeting efficiency and clinical potential of Ad5-based therapeutics. To date, various approaches to retargeting adenoviruses (Ad have been described. These include genetic modification strategies to incorporate peptide ligands (within fiber knob domain, fiber shaft, penton base, pIX or hexon, pseudotyping of capsid proteins to include whole fiber substitutions or fiber knob chimeras, pseudotyping with non-human Ad species or with capsid proteins derived from other viral families, hexon hypervariable region (HVR substitutions and adapter-based conjugation/crosslinking of scFv, growth factors or monoclonal antibodies directed against surface-expressed target antigens. In order to maximize retargeting, strategies which permit detargeting from undesirable interactions between the Ad capsid and components of the circulatory system (e.g. coagulation factors, erythrocytes, pre-existing neutralizing antibodies, can be employed simultaneously. Detargeting can be achieved by genetic ablation of native receptor-binding determinants, ablation of “bridging interactions” such as those which occur between the hexon of Ad5 and coagulation factor X (FX, or alternatively, through the use of polymer

Long-Term Efficacy Following Readministration of an Adeno-Associated Virus Vector in Dogs with Glycogen Storage Disease Type Ia

Science.gov (United States)

Demaster, Amanda; Luo, Xiaoyan; Curtis, Sarah; Williams, Kyha D.; Landau, Dustin J.; Drake, Elizabeth J.; Kozink, Daniel M.; Bird, Andrew; Crane, Bayley; Sun, Francis; Pinto, Carlos R.; Brown, Talmage T.; Kemper, Alex R.

2012-01-01

Abstract Glycogen storage disease type Ia (GSD-Ia) is the inherited deficiency of glucose-6-phosphatase (G6Pase), primarily found in liver and kidney, which causes life-threatening hypoglycemia. Dogs with GSD-Ia were treated with double-stranded adeno-associated virus (AAV) vectors encoding human G6Pase. Administration of an AAV9 pseudotyped (AAV2/9) vector to seven consecutive GSD-Ia neonates prevented hypoglycemia during fasting for up to 8 hr; however, efficacy eventually waned between 2 and 30 months of age, and readministration of a new pseudotype was eventually required to maintain control of hypoglycemia. Three of these dogs succumbed to acute hypoglycemia between 7 and 9 weeks of age; however, this demise could have been prevented by earlier readministration an AAV vector, as demonstrated by successful prevention of mortality of three dogs treated earlier in life. Over the course of this study, six out of nine dogs survived after readministration of an AAV vector. Of these, each dog required readministration on average every 9 months. However, two were not retreated until >34 months of age, while one with preexisting antibodies was re-treated three times in 10 months. Glycogen content was normalized in the liver following vector administration, and G6Pase activity was increased in the liver of vector-treated dogs in comparison with GSD-Ia dogs that received only with dietary treatment. G6Pase activity reached approximately 40% of normal in two female dogs following AAV2/9 vector administration. Elevated aspartate transaminase in absence of inflammation indicated that hepatocellular turnover in the liver might drive the loss of vector genomes. Survival was prolonged for up to 60 months in dogs treated by readministration, and all dogs treated by readministration continue to thrive despite the demonstrated risk for recurrent hypoglycemia and mortality from waning efficacy of the AAV2/9 vector. These preclinical data support the further translation of AAV

Genome-Wide Analysis of Transposon and Retroviral Insertions Reveals Preferential Integrations in Regions of DNA Flexibility.

Science.gov (United States)

Vrljicak, Pavle; Tao, Shijie; Varshney, Gaurav K; Quach, Helen Ngoc Bao; Joshi, Adita; LaFave, Matthew C; Burgess, Shawn M; Sampath, Karuna

2016-04-07

DNA transposons and retroviruses are important transgenic tools for genome engineering. An important consideration affecting the choice of transgenic vector is their insertion site preferences. Previous large-scale analyses of Ds transposon integration sites in plants were done on the basis of reporter gene expression or germ-line transmission, making it difficult to discern vertebrate integration preferences. Here, we compare over 1300 Ds transposon integration sites in zebrafish with Tol2 transposon and retroviral integration sites. Genome-wide analysis shows that Ds integration sites in the presence or absence of marker selection are remarkably similar and distributed throughout the genome. No strict motif was found, but a preference for structural features in the target DNA associated with DNA flexibility (Twist, Tilt, Rise, Roll, Shift, and Slide) was observed. Remarkably, this feature is also found in transposon and retroviral integrations in maize and mouse cells. Our findings show that structural features influence the integration of heterologous DNA in genomes, and have implications for targeted genome engineering. Copyright © 2016 Vrljicak et al.

Construction of retrovirus vector taking MDR1/ACBC1 and its ...

African Journals Online (AJOL)

We successfully observed the expression of the reporter gene-GFP by using the green light fluorescence microscope and the p-glycoprotein (P-gp) expressed by exogenous gene MDR1 by Western Blotting. All these facts indicated that the retroviral vector PMX-flag-MDR1-GFP had successfully been transfected into ...

Bidirectional Retroviral Integration Site PCR Methodology and Quantitative Data Analysis Workflow.

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Suryawanshi, Gajendra W; Xu, Song; Xie, Yiming; Chou, Tom; Kim, Namshin; Chen, Irvin S Y; Kim, Sanggu

2017-06-14

Integration Site (IS) assays are a critical component of the study of retroviral integration sites and their biological significance. In recent retroviral gene therapy studies, IS assays, in combination with next-generation sequencing, have been used as a cell-tracking tool to characterize clonal stem cell populations sharing the same IS. For the accurate comparison of repopulating stem cell clones within and across different samples, the detection sensitivity, data reproducibility, and high-throughput capacity of the assay are among the most important assay qualities. This work provides a detailed protocol and data analysis workflow for bidirectional IS analysis. The bidirectional assay can simultaneously sequence both upstream and downstream vector-host junctions. Compared to conventional unidirectional IS sequencing approaches, the bidirectional approach significantly improves IS detection rates and the characterization of integration events at both ends of the target DNA. The data analysis pipeline described here accurately identifies and enumerates identical IS sequences through multiple steps of comparison that map IS sequences onto the reference genome and determine sequencing errors. Using an optimized assay procedure, we have recently published the detailed repopulation patterns of thousands of Hematopoietic Stem Cell (HSC) clones following transplant in rhesus macaques, demonstrating for the first time the precise time point of HSC repopulation and the functional heterogeneity of HSCs in the primate system. The following protocol describes the step-by-step experimental procedure and data analysis workflow that accurately identifies and quantifies identical IS sequences.

Molecular purging of multiple myeloma cells by ex-vivo culture and retroviral transduction of mobilized-blood CD34+ cells

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Corneo Gianmarco

2007-07-01

Full Text Available Abstract Background Tumor cell contamination of the apheresis in multiple myeloma is likely to affect disease-free and overall survival after autografting. Objective To purge myeloma aphereses from tumor contaminants with a novel culture-based purging method. Methods We cultured myeloma-positive CD34+ PB samples in conditions that retained multipotency of hematopoietic stem cells, but were unfavourable to survival of plasma cells. Moreover, we exploited the resistance of myeloma plasma cells to retroviral transduction by targeting the hematopoietic CD34+ cell population with a retroviral vector carrying a selectable marker (the truncated form of the human receptor for nerve growth factor, ΔNGFR. We performed therefore a further myeloma purging step by selecting the transduced cells at the end of the culture. Results Overall recovery of CD34+ cells after culture was 128.5%; ΔNGFR transduction rate was 28.8% for CD34+ cells and 0% for CD138-selected primary myeloma cells, respectively. Recovery of CD34+ cells after ΔNGFR selection was 22.3%. By patient-specific Ig-gene rearrangements, we assessed a decrease of 0.7–1.4 logs in tumor load after the CD34+ cell selection, and up to 2.3 logs after culture and ΔNGFR selection. Conclusion We conclude that ex-vivo culture and retroviral-mediated transduction of myeloma leukaphereses provide an efficient tumor cell purging.

Retroviral-mediated gene transfer of human phenylalanine hydroxylase into NIH 3T3 and hepatoma cells

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Ledley, F.D.; Grenett, H.E.; McGinnis-Shelnutt, M.; Woo, S.L.C.

1986-01-01

Phenylketonuria (PKU) is caused by deficiency of the hepatic enzyme phenylalanine hydroxylase (PAH). A full-length human PAH cDNA sequence has been inserted into pzip-neoSV(X), which is a retroviral vector containing the bacterial neo gene. The recombinant has been transfected into Psi2 cells, which provide synthesis of the retroviral capsid. Recombinant virus was detected in the culture medium of the transfected Psi2 cells, which is capable of transmitting the human PAH gene into mouse NIH 3T3 cells by infection leading to stable incorporation of the recombinant provirus. Infected cells express PAH mRNA, immunoreactive PAH protein, and exhibit pterin-dependent phenylaline hydroxylase activity. The recombinant virus is also capable of infecting a mouse hepatoma cell line that does not normal synthesize PAH. PAH activity is present in the cellular extracts and the entire hydroxylation system is reconstituted in the hepatoma cells infected with the recombinant viruses. Thus, recombinant viruses containing human PAH cDNA provide a means for introducing functional PAH into mammalian cells of hepatic origin and can potentially be introduced into whole animals as a model for somatic gene therapy for PKU.

Highly efficient gene transfer using a retroviral vector into murine T cells for preclinical chimeric antigen receptor-expressing T cell therapy

International Nuclear Information System (INIS)

Kusabuka, Hotaka; Fujiwara, Kento; Tokunaga, Yusuke; Hirobe, Sachiko; Nakagawa, Shinsaku; Okada, Naoki

2016-01-01

Adoptive immunotherapy using chimeric antigen receptor-expressing T (CAR-T) cells has attracted attention as an efficacious strategy for cancer treatment. To prove the efficacy and safety of CAR-T cell therapy, the elucidation of immunological mechanisms underlying it in mice is required. Although a retroviral vector (Rv) is mainly used for the introduction of CAR to murine T cells, gene transduction efficiency is generally less than 50%. The low transduction efficiency causes poor precision in the functional analysis of CAR-T cells. We attempted to improve the Rv gene transduction protocol to more efficiently generate functional CAR-T cells by optimizing the period of pre-cultivation and antibody stimulation. In the improved protocol, gene transduction efficiency to murine T cells was more than 90%. In addition, almost all of the prepared murine T cells expressed CAR after puromycin selection. These CAR-T cells had antigen-specific cytotoxic activity and secreted multiple cytokines by antigen stimulation. We believe that our optimized gene transduction protocol for murine T cells contributes to the advancement of T cell biology and development of immunotherapy using genetically engineered T cells. - Highlights: • We established highly efficient gene transduction protocols for murine T cells. • CD8"+ CAR-T cells had antigen-specific cytotoxic activity. • CD4"+ CAR-T cells secreted multiple cytokines by antigen stimulation. • This finding can contribute to the development of T-cell biology and immunotherapy.

Highly efficient gene transfer using a retroviral vector into murine T cells for preclinical chimeric antigen receptor-expressing T cell therapy

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Kusabuka, Hotaka; Fujiwara, Kento; Tokunaga, Yusuke; Hirobe, Sachiko; Nakagawa, Shinsaku, E-mail: nakagawa@phs.osaka-u.ac.jp; Okada, Naoki, E-mail: okada@phs.osaka-u.ac.jp

2016-04-22

Adoptive immunotherapy using chimeric antigen receptor-expressing T (CAR-T) cells has attracted attention as an efficacious strategy for cancer treatment. To prove the efficacy and safety of CAR-T cell therapy, the elucidation of immunological mechanisms underlying it in mice is required. Although a retroviral vector (Rv) is mainly used for the introduction of CAR to murine T cells, gene transduction efficiency is generally less than 50%. The low transduction efficiency causes poor precision in the functional analysis of CAR-T cells. We attempted to improve the Rv gene transduction protocol to more efficiently generate functional CAR-T cells by optimizing the period of pre-cultivation and antibody stimulation. In the improved protocol, gene transduction efficiency to murine T cells was more than 90%. In addition, almost all of the prepared murine T cells expressed CAR after puromycin selection. These CAR-T cells had antigen-specific cytotoxic activity and secreted multiple cytokines by antigen stimulation. We believe that our optimized gene transduction protocol for murine T cells contributes to the advancement of T cell biology and development of immunotherapy using genetically engineered T cells. - Highlights: • We established highly efficient gene transduction protocols for murine T cells. • CD8{sup +} CAR-T cells had antigen-specific cytotoxic activity. • CD4{sup +} CAR-T cells secreted multiple cytokines by antigen stimulation. • This finding can contribute to the development of T-cell biology and immunotherapy.

Enhanced immunosurveillance for animal morbilliviruses using vesicular stomatitis virus (VSV) pseudotypes.

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Logan, Nicola; Dundon, William G; Diallo, Adama; Baron, Michael D; James Nyarobi, M; Cleaveland, Sarah; Keyyu, Julius; Fyumagwa, Robert; Hosie, Margaret J; Willett, Brian J

2016-11-11

The measurement of virus-specific neutralising antibodies represents the "gold-standard" for diagnostic serology. For animal morbilliviruses, such as peste des petits ruminants (PPRV) or rinderpest virus (RPV), live virus-based neutralisation tests require high-level biocontainment to prevent the accidental escape of the infectious agents. In this study, we describe the adaptation of a replication-defective vesicular stomatitis virus (VSVΔG) based pseudotyping system for the measurement of neutralising antibodies against animal morbilliviruses. By expressing the haemagglutinin (H) and fusion (F) proteins of PPRV on VSVΔG pseudotypes bearing a luciferase marker gene, neutralising antibody titres could be measured rapidly and with high sensitivity. Serological responses against the four distinct lineages of PPRV could be measured simultaneously and cross-neutralising responses against other morbilliviruses compared. Using this approach, we observed that titres of neutralising antibodies induced by vaccination with live attenuated PPRV were lower than those induced by wild type virus infection and the level of cross-lineage neutralisation varied between vaccinates. By comparing neutralising responses from animals infected with either PPRV or RPV, we found that responses were highest against the homologous virus, indicating that retrospective analyses of serum samples could be used to confirm the nature of the original pathogen to which an animal had been exposed. Accordingly, when screening sera from domestic livestock and wild ruminants in Tanzania, we detected evidence of cross-species infection with PPRV, canine distemper virus (CDV) and a RPV-related bovine morbillivirus, suggesting that exposure to animal morbilliviruses may be more widespread than indicated previously using existing diagnostic techniques. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Hepatitis C virus quasispecies and pseudotype analysis from acute infection to chronicity in HIV-1 co-infected individuals.

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Ferns, R Bridget; Tarr, Alexander W; Hue, Stephane; Urbanowicz, Richard A; McClure, C Patrick; Gilson, Richard; Ball, Jonathan K; Nastouli, Eleni; Garson, Jeremy A; Pillay, Deenan

2016-05-01

HIV-1 infected patients who acquire HCV infection have higher rates of chronicity and liver disease progression than patients with HCV mono-infection. Understanding early events in this pathogenic process is important. We applied single genome sequencing of the E1 to NS3 regions and viral pseudotype neutralization assays to explore the consequences of viral quasispecies evolution from pre-seroconversion to chronicity in four co-infected individuals (mean follow up 566 days). We observed that one to three founder viruses were transmitted. Relatively low viral sequence diversity, possibly related to an impaired immune response, due to HIV infection was observed in three patients. However, the fourth patient, after an early purifying selection displayed increasing E2 sequence evolution, possibly related to being on suppressive antiretroviral therapy. Viral pseudotypes generated from HCV variants showed relative resistance to neutralization by autologous plasma but not to plasma collected from later time points, confirming ongoing virus escape from antibody neutralization. Copyright © 2016 Elsevier Inc. All rights reserved.

Resting lymphocyte transduction with measles virus glycoprotein pseudotyped lentiviral vectors relies on CD46 and SLAM

International Nuclear Information System (INIS)

Zhou Qi; Schneider, Irene C.; Gallet, Manuela; Kneissl, Sabrina; Buchholz, Christian J.

2011-01-01

The measles virus (MV) glycoproteins hemagglutinin (H) and fusion (F) were recently shown to mediate transduction of resting lymphocytes by lentiviral vectors. MV vaccine strains use CD46 or signaling lymphocyte activation molecule (SLAM) as receptor for cell entry. A panel of H protein mutants derived from vaccine strain or wild-type MVs that lost or gained CD46 or SLAM receptor usage were investigated for their ability to mediate gene transfer into unstimulated T lymphocytes. The results demonstrate that CD46 is sufficient for efficient vector particle association with unstimulated lymphocytes. For stable gene transfer into these cells, however, both MV receptors were found to be essential.

Acute retroviral syndrome in Slovenian patients infected with HIV

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Mateja Pirš

2005-06-01

Full Text Available Background: Two to six weeks after primary infection with HIV 50 to 90 percent of patients develop an acute retroviral syndrome which usually presents with mononucleosis or flu-like illness. Due to nonspecific symptoms ARS is frequently misdiagnosed.Patients and methods: Data of Slovenian patients with acute retroviral syndrome is shown, as well as their symptoms, approaches to management and diagnostic particularities of primary HIV infection.Conclusions: The combination of particular symptoms and epidemiological data should lead us to consider the possibility of an early HIV infection.

Prolonged Integration Site Selection of a Lentiviral Vector in the Genome of Human Keratinocytes.

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Qian, Wei; Wang, Yong; Li, Rui-Fu; Zhou, Xin; Liu, Jing; Peng, Dai-Zhi

2017-03-03

BACKGROUND Lentiviral vectors have been successfully used for human skin cell gene transfer studies. Defining the selection of integration sites for retroviral vectors in the host genome is crucial in risk assessment analysis of gene therapy. However, genome-wide analyses of lentiviral integration sites in human keratinocytes, especially after prolonged growth, are poorly understood. MATERIAL AND METHODS In this study, 874 unique lentiviral vector integration sites in human HaCaT keratinocytes after long-term culture were identified and analyzed with the online tool GTSG-QuickMap and SPSS software. RESULTS The data indicated that lentiviral vectors showed integration site preferences for genes and gene-rich regions. CONCLUSIONS This study will likely assist in determining the relative risks of the lentiviral vector system and in the design of a safe lentiviral vector system in the gene therapy of skin diseases.

Retrovirally transduced NCAM140 facilitates neuronal fate choice of hippocampal progenitor cells.

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Kim, Ju Hee; Lee, Jung-Ha; Park, Jin-Yong; Park, Chang-Hwan; Yun, Chae-Ok; Lee, Sang-Hun; Lee, Yong-Sung; Son, Hyeon

2005-07-01

Neural cell adhesion molecule (NCAM) influences proliferation and differentiation of neuronal cells. However, only a little is known about the downstream effects of NCAM signalling, such as alterations in gene transcription, which are associated with cell fate choice. To examine whether NCAM plays a role in cell fate choice during hippocampal neurogenesis, we performed a gain-of-function study, using a retroviral vector which contained full-length NCAM140 cDNA and the marker gene EGFP, and found that NCAM140 promoted neurogenesis by activating proneural transcription activators with concurrent inhibition of gliogenesis. The enhanced transcript levels of proneural transcription factors in NCAM140-transduced cells were down-regulated by treatment of the cells with mitogen-activated protein kinase kinase (MEK) inhibitor PD098059. Overall, these findings suggest that NCAM140 may facilitate hippocampal neurogenesis via regulation of proneurogenic transcription factors in an extracellular signal-regulated kinase (ERK)-dependent manner.

Cell-type-specific gene delivery into neuronal cells in vitro and in vivo

International Nuclear Information System (INIS)

Parveen, Zahida; Mukhtar, Muhammad; Rafi, Mohammed; Wenger, David A.; Siddiqui, Khwaja M.; Siler, Catherine A.; Dietzschold, Bernhard; Pomerantz, Roger J.; Schnell, Matthias J.; Dornburg, Ralph

2003-01-01

The avian retroviruses reticuloendotheliosis virus strain A (REV-A) and spleen necrosis virus (SNV) are not naturally infectious in human cells. However, REV-A-derived viral vectors efficiently infect human cells when they are pseudotyped with envelope proteins displaying targeting ligands specific for human cell-surface receptors. Here we report that vectors containing the gag region of REV-A and pol of SNV can be pseudotyped with the envelope protein of vesicular stomatitis virus (VSV) and the glycoproteins of different rabies virus (RV) strains. Vectors pseudotyped with the envelope protein of the highly neurotropic RV strain CVS-N2c facilitated cell type-specific gene delivery into mouse and human neurons, but did not infect other human cell types. Moreover, when such vector particles were injected into the brain of newborn mice, only neuronal cells were infected in vivo. Cell-type-specific gene delivery into neurons may present quite specific gene therapy approaches for many degenerative diseases of the brain

Lentiviral Vectors for Cancer Immunotherapy and Clinical Applications

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David Escors

2013-07-01

Full Text Available The success of immunotherapy against infectious diseases has shown us the powerful potential that such a treatment offers, and substantial work has been done to apply this strategy in the fight against cancer. Cancer is however a fiercer opponent than pathogen-caused diseases due to natural tolerance towards tumour associated antigens and tumour-induced immunosuppression. Recent gene therapy clinical trials with viral vectors have shown clinical efficacy in the correction of genetic diseases, HIV and cancer. The first successful gene therapy clinical trials were carried out with onco(g-retroviral vectors but oncogenesis by insertional mutagenesis appeared as a serious complication. Lentiviral vectors have emerged as a potentially safer strategy, and recently the first clinical trial of patients with advanced leukemia using lentiviral vectors has proven successful. Additionally, therapeutic lentivectors have shown clinical efficacy for the treatment of HIV, X-linked adrenoleukodystrophy, and b-thalassaemia. This review aims at describing lentivectors and how they can be utilized to boost anti-tumour immune responses by manipulating the effector immune cells.

Lentiviral Vectors for Cancer Immunotherapy and Clinical Applications

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Liechtenstein, Therese, E-mail: t.liechtenstein.12@ucl.ac.uk [University College London, 5 University Street, London, WC1E 6JF (United Kingdom); Perez-Janices, Noemi; Escors, David [University College London, 5 University Street, London, WC1E 6JF (United Kingdom); Navarrabiomed Fundacion Miguel Servet, 3 Irunlarrea St., Hospital Complex of Navarra, 31008 Pamplona, Navarra (Spain)

2013-07-02

The success of immunotherapy against infectious diseases has shown us the powerful potential that such a treatment offers, and substantial work has been done to apply this strategy in the fight against cancer. Cancer is however a fiercer opponent than pathogen-caused diseases due to natural tolerance towards tumour associated antigens and tumour-induced immunosuppression. Recent gene therapy clinical trials with viral vectors have shown clinical efficacy in the correction of genetic diseases, HIV and cancer. The first successful gene therapy clinical trials were carried out with onco(γ-)retroviral vectors but oncogenesis by insertional mutagenesis appeared as a serious complication. Lentiviral vectors have emerged as a potentially safer strategy, and recently the first clinical trial of patients with advanced leukemia using lentiviral vectors has proven successful. Additionally, therapeutic lentivectors have shown clinical efficacy for the treatment of HIV, X-linked adrenoleukodystrophy, and β-thalassaemia. This review aims at describing lentivectors and how they can be utilized to boost anti-tumour immune responses by manipulating the effector immune cells.

Lentiviral Vectors for Cancer Immunotherapy and Clinical Applications

International Nuclear Information System (INIS)

Liechtenstein, Therese; Perez-Janices, Noemi; Escors, David

2013-01-01

The success of immunotherapy against infectious diseases has shown us the powerful potential that such a treatment offers, and substantial work has been done to apply this strategy in the fight against cancer. Cancer is however a fiercer opponent than pathogen-caused diseases due to natural tolerance towards tumour associated antigens and tumour-induced immunosuppression. Recent gene therapy clinical trials with viral vectors have shown clinical efficacy in the correction of genetic diseases, HIV and cancer. The first successful gene therapy clinical trials were carried out with onco(γ-)retroviral vectors but oncogenesis by insertional mutagenesis appeared as a serious complication. Lentiviral vectors have emerged as a potentially safer strategy, and recently the first clinical trial of patients with advanced leukemia using lentiviral vectors has proven successful. Additionally, therapeutic lentivectors have shown clinical efficacy for the treatment of HIV, X-linked adrenoleukodystrophy, and β-thalassaemia. This review aims at describing lentivectors and how they can be utilized to boost anti-tumour immune responses by manipulating the effector immune cells

Design of a titering assay for lentiviral vectors utilizing direct extraction of DNA from transduced cells in microtiter plates

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Michele E Murphy

2016-01-01

Full Text Available Using lentiviral vector products in clinical applications requires an accurate method for measuring transduction titer. For vectors lacking a marker gene, quantitative polymerase chain reaction is used to evaluate the number of vector DNA copies in transduced target cells, from which a transduction titer is calculated. Immune Design previously described an integration-deficient lentiviral vector pseudotyped with a modified Sindbis virus envelope for use in cancer immunotherapy (VP02, of the ZVex platform. Standard protocols for titering integration-competent lentiviral vectors employ commercial spin columns to purify vector DNA from transduced cells, but such columns are not optimized for isolation of extrachromosomal (nonintegrated DNA. Here, we describe a 96-well transduction titer assay in which DNA extraction is performed in situ in the transduction plate, yielding quantitative recovery of extrachromosomal DNA. Vector titers measured by this method were higher than when commercial spin columns were used for DNA isolation. Evaluation of the method's specificity, linear range, and precision demonstrate that it is suitable for use as a lot release assay to support clinical trials with VP02. Finally, the method is compatible with titering both integrating and nonintegrating lentiviral vectors, suggesting that it may be used to evaluate the transduction titer for any lentiviral vector.

Oncolytic Adenovirus: Strategies and Insights for Vector Design and Immuno-Oncolytic Applications

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Hanni Uusi-Kerttula

2015-11-01

Full Text Available Adenoviruses (Ad are commonly used both experimentally and clinically, including oncolytic virotherapy applications. In the clinical area, efficacy is frequently hampered by the high rates of neutralizing immunity, estimated as high as 90% in some populations that promote vector clearance and limit bioavailability for tumor targeting following systemic delivery. Active tumor targeting is also hampered by the ubiquitous nature of the Ad5 receptor, hCAR, as well as the lack of highly tumor-selective targeting ligands and suitable targeting strategies. Furthermore, significant off-target interactions between the viral vector and cellular and proteinaceous components of the bloodstream have been documented that promote uptake into non-target cells and determine dose-limiting toxicities. Novel strategies are therefore needed to overcome the obstacles that prevent efficacious Ad deployment for wider clinical applications. The use of less seroprevalent Ad serotypes, non-human serotypes, capsid pseudotyping, chemical shielding and genetic masking by heterologous peptide incorporation are all potential strategies to achieve efficient vector escape from humoral immune recognition. Conversely, selective vector arming with immunostimulatory agents can be utilized to enhance their oncolytic potential by activation of cancer-specific immune responses against the malignant tissues. This review presents recent advantages and pitfalls occurring in the field of adenoviral oncolytic therapies.

Detection of a human intracisternal A-type retroviral particle antigenically related to HIV

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Garry, R. F.; Fermin, C. D.; Hart, D. J.; Alexander, S. S.; Donehower, L. A.; Luo-Zhang, H.

1990-01-01

Sjogren's syndrome is an autoimmune disease that is characterized by dryness of the mouth and eyes. The loss of salivary and lacrimal gland function is accompanied by lymphocytic infiltration. Because similar symptoms and glandular pathology are observed in certain persons infected with human immunodeficiency virus (HIV), a search was initiated for a possible retroviral etiology in this syndrome. A human intracisternal A-type retroviral particle that is antigenically related to HIV was detected in lymphoblastoid cells exposed to homogenates of salivary tissue from patients with Sjogren's syndrome. Comparison of this retroviral particle to HIV indicates that they are distinguishable by several ultrastructural, physical, and enzymatic criteria.

Polyploidization without mitosis improves in vivo liver transduction with lentiviral vectors.

Science.gov (United States)

Pichard, Virginie; Couton, Dominique; Desdouets, Chantal; Ferry, Nicolas

2013-02-01

Lentiviral vectors are efficient gene delivery vehicles for therapeutic and research applications. In contrast to oncoretroviral vectors, they are able to infect most nonproliferating cells. In the liver, induction of cell proliferation dramatically improved hepatocyte transduction using all types of retroviral vectors. However, the precise relationship between hepatocyte division and transduction efficiency has not been determined yet. Here we compared gene transfer efficiency in the liver after in vivo injection of recombinant lentiviral or Moloney murine leukemia viral (MoMuLV) vectors in hepatectomized rats treated or not with retrorsine, an alkaloid that blocks hepatocyte division and induces megalocytosis. Partial hepatectomy alone resulted in a similar increase in hepatocyte transduction using either vector. In retrorsine-treated and partially hepatectomized rats, transduction with MoMuLV vectors dropped dramatically. In contrast, we observed that retrorsine treatment combined with partial hepatectomy increased lentiviral transduction to higher levels than hepatectomy alone. Analysis of nuclear ploidy in single cells showed that a high level of transduction was associated with polyploidization. In conclusion, endoreplication could be exploited to improve the efficiency of liver-directed lentiviral gene therapy.

Correction of glucocerebrosidase deficiency after retroviral-mediated gene transfer into hematopoietic progenitor cells from patients with Gaucher disease

International Nuclear Information System (INIS)

Fink, J.K.; Correll, P.H.; Perry, L.K.; Brady, R.O.; Karlsson, S.

1990-01-01

Retroviral gene transfer has been used successfully to correct the glucocerebrosidase (GCase) deficiency in primary hematopoietic cells from patients with Gaucher disease. For this model of somatic gene therapy, the authors developed a high-titer, amphotropic retroviral vector designated NTG in which the human GCase gene was driven by the mutant polyoma virus enhancer/herpesvirus thymidine kinase gene (tk) promoter (Py + /Htk). NTG normalized GCase activity in transduced Gaucher fibroblasts and efficiently infected human monocytic and erythroleukemic cell lines. RNA blot-hybridization (Northern blot) analysis of these hemaptopoietic cell lines showed unexpectedly high-level expression from the Moloney murine leukemia virus long terminal repeat (Mo-MLV LTR) and levels of Py + /Htk enhancer/promoter-initiated human GCase RNA that approximated endogenous GCase RNA levels. Furthermore, NTG efficiently infected human hematopoietic progenitor cells. Detection of the provirus in approximately one-third of NTG-infected progenitor colonies that had not been selected in G418-containing medium indicates that relative resistance to G418 underestimated the actual gene transfer efficiency. Northern blot analysis of NTG-infected, progenitor-derived cells showed expression from both the Mo-MLV LTR and the Py + /Htk enhancer/promoter. NTG-transduced hematopoietic progenitor cells from patients with Gaucher disease generated progeny in which GCase activity has been normalized

Correction of glucocerebrosidase deficiency after retroviral-mediated gene transfer into hematopoietic progenitor cells from patients with Gaucher disease

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Fink, J.K.; Correll, P.H.; Perry, L.K.; Brady, R.O.; Karlsson, S. (National Institutes of Health, Bethesda, MD (USA))

1990-03-01

Retroviral gene transfer has been used successfully to correct the glucocerebrosidase (GCase) deficiency in primary hematopoietic cells from patients with Gaucher disease. For this model of somatic gene therapy, the authors developed a high-titer, amphotropic retroviral vector designated NTG in which the human GCase gene was driven by the mutant polyoma virus enhancer/herpesvirus thymidine kinase gene (tk) promoter (Py{sup +}/Htk). NTG normalized GCase activity in transduced Gaucher fibroblasts and efficiently infected human monocytic and erythroleukemic cell lines. RNA blot-hybridization (Northern blot) analysis of these hemaptopoietic cell lines showed unexpectedly high-level expression from the Moloney murine leukemia virus long terminal repeat (Mo-MLV LTR) and levels of Py{sup +}/Htk enhancer/promoter-initiated human GCase RNA that approximated endogenous GCase RNA levels. Furthermore, NTG efficiently infected human hematopoietic progenitor cells. Detection of the provirus in approximately one-third of NTG-infected progenitor colonies that had not been selected in G418-containing medium indicates that relative resistance to G418 underestimated the actual gene transfer efficiency. Northern blot analysis of NTG-infected, progenitor-derived cells showed expression from both the Mo-MLV LTR and the Py{sup +}/Htk enhancer/promoter. NTG-transduced hematopoietic progenitor cells from patients with Gaucher disease generated progeny in which GCase activity has been normalized.

Differentiated neuroprogenitor cells incubated with human or canine adenovirus, or lentiviral vectors have distinct transcriptome profiles.

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Stefania Piersanti

Full Text Available Several studies have demonstrated the potential for vector-mediated gene transfer to the brain. Helper-dependent (HD human (HAd and canine (CAV-2 adenovirus, and VSV-G-pseudotyped self-inactivating HIV-1 vectors (LV effectively transduce human brain cells and their toxicity has been partly analysed. However, their effect on the brain homeostasis is far from fully defined, especially because of the complexity of the central nervous system (CNS. With the goal of dissecting the toxicogenomic signatures of the three vectors for human neurons, we transduced a bona fide human neuronal system with HD-HAd, HD-CAV-2 and LV. We analysed the transcriptional response of more than 47,000 transcripts using gene chips. Chip data showed that HD-CAV-2 and LV vectors activated the innate arm of the immune response, including Toll-like receptors and hyaluronan circuits. LV vector also induced an IFN response. Moreover, HD-CAV-2 and LV vectors affected DNA damage pathways--but in opposite directions--suggesting a differential response of the p53 and ATM pathways to the vector genomes. As a general response to the vectors, human neurons activated pro-survival genes and neuron morphogenesis, presumably with the goal of re-establishing homeostasis. These data are complementary to in vivo studies on brain vector toxicity and allow a better understanding of the impact of viral vectors on human neurons, and mechanistic approaches to improve the therapeutic impact of brain-directed gene transfer.

Chromosomal locations of members of a family of novel endogenous human retroviral genomes

International Nuclear Information System (INIS)

Horn, T.M.; Huebner, K.; Croce, C.; Callahan, R.

1986-01-01

Human cellular DNA contains two distinguishable families of retroviral related sequences. One family shares extensive nucleotide sequence homology with infectious mammalian type C retroviral genomes. The other family contains major regions of homology with the pol genes of infectious type A and B and avian type C and D retroviral genomes. Analysis of the human recombinant clone HLM-2 has shown that the pol gene in the latter family is located within an endogenous proviral genome. The authors show that the proviral genome in HLM-2 and the related recombinant clone HLM-25 are located, respectively, on human chromosomes 1 and 5. Other related proviral genomes are located on chromosomes 7, 8, 11, 14, and 17

Transcriptional Enhancers Induce Insertional Gene Deregulation Independently From the Vector Type and Design

Science.gov (United States)

Maruggi, Giulietta; Porcellini, Simona; Facchini, Giulia; Perna, Serena K; Cattoglio, Claudia; Sartori, Daniela; Ambrosi, Alessandro; Schambach, Axel; Baum, Christopher; Bonini, Chiara; Bovolenta, Chiara; Mavilio, Fulvio; Recchia, Alessandra

2009-01-01

The integration characteristics of retroviral (RV) vectors increase the probability of interfering with the regulation of cellular genes, and account for a tangible risk of insertional mutagenesis in treated patients. To assess the potential genotoxic risk of conventional or self-inactivating (SIN) γ-RV and lentiviral (LV) vectors independently from the biological consequences of the insertion event, we developed a quantitative assay based on real-time reverse transcriptase—PCR on low-density arrays to evaluate alterations of gene expression in individual primary T-cell clones. We show that the Moloney leukemia virus long terminal repeat (LTR) enhancer has the strongest activity in both a γ-RV and a LV vector context, while an internal cellular promoter induces deregulation of gene expression less frequently, at a shorter range and to a lower extent in both vector types. Downregulation of gene expression was observed only in the context of LV vectors. This study indicates that insertional gene activation is determined by the characteristics of the transcriptional regulatory elements carried by the vector, and is largely independent from the vector type or design. PMID:19293778

Improved vaccine protection against retrovirus infection after co-administration of adenoviral vectors encoding viral antigens and type I interferon subtypes

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Groitl Peter

2011-09-01

Full Text Available Abstract Background Type I interferons (IFNs exhibit direct antiviral effects, but also distinct immunomodulatory properties. In this study, we analyzed type I IFN subtypes for their effect on prophylactic adenovirus-based anti-retroviral vaccination of mice against Friend retrovirus (FV or HIV. Results Mice were vaccinated with adenoviral vectors encoding FV Env and Gag proteins alone or in combination with vectors encoding IFNα1, IFNα2, IFNα4, IFNα5, IFNα6, IFNα9 or IFNβ. Only the co-administration of adenoviral vectors encoding IFNα2, IFNα4, IFNα6 and IFNα9 resulted in strongly improved immune protection of vaccinated mice from subsequent FV challenge infection with high control over FV-induced splenomegaly and reduced viral loads. The level of protection correlated with augmented virus-specific CD4+ T cell responses and enhanced antibody titers. Similar results were obtained when mice were vaccinated against HIV with adenoviral vectors encoding HIV Env and Gag-Pol in combination with various type I IFN encoding vectors. Here mainly CD4+ T cell responses were enhanced by IFNα subtypes. Conclusions Our results indicate that certain IFNα subtypes have the potential to improve the protective effect of adenovirus-based vaccines against retroviruses. This correlated with augmented virus-specific CD4+ T cell and antibody responses. Thus, co-expression of select type I IFNs may be a valuable tool for the development of anti-retroviral vaccines.

Potent and reversible lentiviral vector restriction in murine induced pluripotent stem cells.

Science.gov (United States)

Geis, Franziska K; Galla, Melanie; Hoffmann, Dirk; Kuehle, Johannes; Zychlinski, Daniela; Maetzig, Tobias; Schott, Juliane W; Schwarzer, Adrian; Goffinet, Christine; Goff, Stephen P; Schambach, Axel

2017-05-31

Retroviral vectors are derived from wild-type retroviruses, can be used to study retrovirus-host interactions and are effective tools in gene and cell therapy. However, numerous cell types are resistant or less permissive to retrovirus infection due to the presence of active defense mechanisms, or the absence of important cellular host co-factors. In contrast to multipotent stem cells, pluripotent stem cells (PSC) have potential to differentiate into all three germ layers. Much remains to be elucidated in the field of anti-viral immunity in stem cells, especially in PSC. In this study, we report that transduction with HIV-1-based, lentiviral vectors (LV) is impaired in murine PSC. Analyses of early retroviral events in induced pluripotent stem cells (iPSC) revealed that the restriction is independent of envelope choice and does not affect reverse transcription, but perturbs nuclear entry and proviral integration. Proteasomal inhibition by MG132 could not circumvent the restriction. However, prevention of cyclophilin A (CypA) binding to the HIV-1 capsid via use of either a CypA inhibitor (cyclosporine A) or CypA-independent capsid mutants improved transduction. In addition, application of higher vector doses also increased transduction. Our data revealed a CypA mediated restriction in iPSC, which was acquired during reprogramming, associated with pluripotency and relieved upon subsequent differentiation. We showed that murine PSC and iPSC are less susceptible to LV. The block observed in iPSC was CypA-dependent and resulted in reduced nuclear entry of viral DNA and proviral integration. Our study helps to improve transduction of murine pluripotent cells with HIV-1-based vectors and contributes to our understanding of retrovirus-host interactions in PSC.

Molecular evidence of inefficient transduction of proliferating human B lymphocytes by VSV-pseudotyped HIV-1-derived lentivectors

International Nuclear Information System (INIS)

Serafini, M.; Naldini, L.; Introna, M.

2004-01-01

Lentiviral vectors are attractive tools to transduce dividing and nondividing cells. Human tonsillar B lymphocytes have been purified and induced to proliferate by the addition of anti-CD40 + IL-4 or anti-CD40 + anti-μ signals and transduced at high MOI with a VSV pseudotyped lentivector carrying the eGFP gene under the control of the PGK promoter. Parallel cultures of PHA-stimulated T lymphocytes containing a comparable amount of cycling cells during the infection reached over 70% eGFP transduction. By contrast, only less than 3% B lymphocytes became eGFP positive after 7 days from transduction. Molecular analysis of the viral life cycle shows that cytoplasmic retrotranscribed cDNA and nuclear 2LTR circles are detectable at lower levels and for a shorter period of time in proliferating B cells with respect to proliferating T lymphocytes. Moreover, FACS-sorted eGFP-positive and negative B cell populations were both positive for the presence of retrotranscribed cDNA and 2LTR circles nuclear forms. By contrast, nested Alu-LTR PCR allowed us to detect an integrated provirus in FACS-sorted eGFP-positive cells only. Together with the demonstration that infection in saturation conditions led to an increase in the percentage of transduced cells (reaching 9%), these findings suggest that in proliferating B lymphocytes, lentiviral transduction is an inefficient process blocked at the early steps of the viral life cycle possibly involving partially saturable restriction factors

Our retroviral heritage.

Science.gov (United States)

Patience, C; Wilkinson, D A; Weiss, R A

1997-03-01

Darwin could not have foretold that we are descended from viruses as well as from apes. While there is clear evidence that viral diseases, such as polio and rabies, affected ancient civilizations, viruses were not defined until the early years of this century, shortly after the rediscovery of mendelian genetics. That retroviral genomes can oscillate between infectious and genetic modes of transmission seemed preposterous before the discovery of reverse transcription in 1970. Those of us who had earlier provided mendelian evidence for germ-line transmission of retroviruses were subject of friendly ridicule. Today, the shunting of genetic elements between chromosomes and RNA, and the generation of processed pseudogenes, seems commonplace. It is timely, however, to revisit the topic of human endogenous retroviruses-the subject of this article.

High-resolution structure of a retroviral protease folded as a monomer

International Nuclear Information System (INIS)

Gilski, Miroslaw; Kazmierczyk, Maciej; Krzywda, Szymon; Zábranská, Helena; Cooper, Seth; Popović, Zoran; Khatib, Firas; DiMaio, Frank; Thompson, James; Baker, David; Pichová, Iva; Jaskolski, Mariusz

2011-01-01

The crystal structure of Mason–Pfizer monkey virus protease folded as a monomer has been solved by molecular replacement using a model generated by players of the online game Foldit. The structure shows at high resolution the details of a retroviral protease folded as a monomer which can guide rational design of protease dimerization inhibitors as retroviral drugs. Mason–Pfizer monkey virus (M-PMV), a D-type retrovirus assembling in the cytoplasm, causes simian acquired immunodeficiency syndrome (SAIDS) in rhesus monkeys. Its pepsin-like aspartic protease (retropepsin) is an integral part of the expressed retroviral polyproteins. As in all retroviral life cycles, release and dimerization of the protease (PR) is strictly required for polyprotein processing and virion maturation. Biophysical and NMR studies have indicated that in the absence of substrates or inhibitors M-PMV PR should fold into a stable monomer, but the crystal structure of this protein could not be solved by molecular replacement despite countless attempts. Ultimately, a solution was obtained in mr-rosetta using a model constructed by players of the online protein-folding game Foldit. The structure indeed shows a monomeric protein, with the N- and C-termini completely disordered. On the other hand, the flap loop, which normally gates access to the active site of homodimeric retropepsins, is clearly traceable in the electron density. The flap has an unusual curled shape and a different orientation from both the open and closed states known from dimeric retropepsins. The overall fold of the protein follows the retropepsin canon, but the C α deviations are large and the active-site ‘DTG’ loop (here NTG) deviates up to 2.7 Å from the standard conformation. This structure of a monomeric retropepsin determined at high resolution (1.6 Å) provides important extra information for the design of dimerization inhibitors that might be developed as drugs for the treatment of retroviral infections

A pseudotype baculovirus expressing the capsid protein of foot-and-mouth disease virus and a T-Cell immunogen shows enhanced immunogenicity in mice

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Liu Xiangtao

2011-02-01

Full Text Available Abstract Background Foot-and-mouth disease (FMD is a highly contagious disease of livestock which causes severe economic loss in cloven-hoofed animals. Vaccination is still a major strategy in developing countries to control FMD. Currently, inactivated vaccine of FMDV has been used in many countries with limited success and safety concerns. Development of a novel effective vaccine is must. Methods In the present study, two recombinant pseudotype baculoviruses, one expressing the capsid of foot-and-mouth disease virus (FMDV under the control of a cytomegalovirus immediate early enhancer/promoter (CMV-IE, and the other the caspid plus a T-cell immunogen coding region under a CAG promoter were constructed, and their expression was characterized in mammalian cells. In addition, their immunogenicity in a mouse model was investigated. The humoral and cell-mediated immune responses induced by pseudotype baculovirus were compared with those of inactivated vaccine. Results Indirect immunofluorescence assay (IFA and indirect sandwich-ELISA (IS-ELISA showed both recombinant baculoviruses (with or without T-cell epitopes were transduced efficiently and expressed target proteins in BHK-21 cells. In mice, intramuscular inoculation of recombinants with 1 × 109 or 1 × 1010 PFU/mouse induced the production of FMDV-specific neutralizing antibodies and gamma interferon (IFN-γ. Furthermore, recombinant baculovirus with T-cell epitopes had better immunogenicity than the recombinant without T-cell epitopes as demonstrated by significantly enhanced IFN-γ production (P P Conclusions These results indicate that pseudotype baculovirus-mediated gene delivery could be a alternative strategy to develop a new generation of vaccines against FMDV infection.

Role of complement and antibodies in controlling infection with pathogenic simian immunodeficiency virus (SIV in macaques vaccinated with replication-deficient viral vectors

Directory of Open Access Journals (Sweden)

Strasak Alexander

2009-06-01

Full Text Available Abstract Background We investigated the interplay between complement and antibodies upon priming with single-cycle replicating viral vectors (SCIV encoding SIV antigens combined with Adeno5-SIV or SCIV pseudotyped with murine leukemia virus envelope boosting strategies. The vaccine was applied via spray-immunization to the tonsils of rhesus macaques and compared with systemic regimens. Results Independent of the application regimen or route, viral loads were significantly reduced after challenge with SIVmac239 (p Conclusion The heterologous prime-boost strategy with replication-deficient viral vectors administered exclusively via the tonsils did not induce any neutralizing antibodies before challenge. However, after challenge, comparable SIV-specific humoral immune responses were observed in all vaccinated animals. Immunization with single cycle immunodeficiency viruses mounts humoral immune responses comparable to live-attenuated immunodeficiency virus vaccines.

The core element of a CpG island protects avian sarcoma and leukosis virus-derived vectors from transcriptional silencing

Czech Academy of Sciences Publication Activity Database

Šenigl, Filip; Plachý, Jiří; Hejnar, Jiří

2008-01-01

Roč. 82, č. 16 (2008), s. 7818-7827 ISSN 0022-538X R&D Projects: GA ČR GA204/05/0939; GA ČR GA523/07/1171 Institutional research plan: CEZ:AV0Z50520514 Keywords : anti-methylation protection * retroviral vector * CpG island Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 5.308, year: 2008

Mutational library analysis of selected amino acids in the receptor binding domain of envelope of Akv murine leukemia virus by conditionally replication competent bicistronic vectors

DEFF Research Database (Denmark)

Bahrami, Shervin; Jespersen, Thomas; Pedersen, Finn Skou

2003-01-01

The envelope protein of retroviruses is responsible for viral entry into host cells. Here, we describe a mutational library approach to dissect functional domains of the envelope protein involving a retroviral vector, which expresses both the envelope protein of Akv murine leukemia virus (MLV) an...

Lentiviral Vector Design and Imaging Approaches to Visualize the Early Stages of Cellular Reprogramming

OpenAIRE

Warlich, Eva; Kuehle, Johannes; Cantz, Tobias; Brugman, Martijn H; Maetzig, Tobias; Galla, Melanie; Filipczyk, Adam A; Halle, Stephan; Klump, Hannes; Schöler, Hans R; Baum, Christopher; Schroeder, Timm; Schambach, Axel

2011-01-01

Induced pluripotent stem cells (iPSCs) can be derived from somatic cells by gene transfer of reprogramming transcription factors. Expression levels of these factors strongly influence the overall efficacy to form iPSC colonies, but additional contribution of stochastic cell-intrinsic factors has been proposed. Here, we present engineered color-coded lentiviral vectors in which codon-optimized reprogramming factors are co-expressed by a strong retroviral promoter that is rapidly silenced in iP...

Gene delivery to pancreatic exocrine cells in vivo and in vitro

Directory of Open Access Journals (Sweden)

Houbracken Isabelle

2012-10-01

Full Text Available Abstract Background Effective gene transfer to the pancreas or to pancreatic cells has remained elusive although it is essential for studies of genetic lineage tracing and modulation of gene expression. Different transduction methods and viral vectors were tested in vitro and in vivo, in rat and mouse pancreas. Results For in vitro transfection/transduction of rat exocrine cells lipofection reagents, adenoviral vectors, and Mokola- and VSV-G pseudotyped lentiviral vectors were used. For in vivo transduction of mouse and rat pancreas adenoviral vectors and VSV-G lentiviral vectors were injected into the parenchymal tissue. Both lipofection of rat exocrine cell cultures and transduction with Mokola pseudotyped lentiviral vectors were inefficient and resulted in less than 4% EGFP expressing cells. Adenoviral transduction was highly efficient but its usefulness for gene delivery to rat exocrine cells in vitro was hampered by a drastic increase in cell death. In vitro transduction of rat exocrine cells was most optimal with VSV-G pseudotyped lentiviral vectors, with stable transgene expression, no significant effect on cell survival and about 40% transduced cells. In vivo, pancreatic cells could not be transduced by intra-parenchymal administration of lentiviral vectors in mouse and rat pancreas. However, a high efficiency could be obtained by adenoviral vectors, resulting in transient transduction of mainly exocrine acinar cells. Injection in immune-deficient animals diminished leukocyte infiltration and prolonged transgene expression. Conclusions In summary, our study remarkably demonstrates that transduction of pancreatic exocrine cells requires lentiviral vectors in vitro but adenoviral vectors in vivo.

Luminometric method for screening retroviral protease inhibitors

Czech Academy of Sciences Publication Activity Database

Horáková, D.; Rumlová, Michaela; Pichová, Iva; Ruml, Tomáš

2005-01-01

Roč. 345, č. 1 (2005), s. 96-101 ISSN 0003-2697 R&D Projects: GA AV ČR(CZ) IAA4055304; GA MŠk(CZ) 1M0508; GA MŠk(CZ) 1M0520 Institutional research plan: CEZ:AV0Z40550506 Keywords : retroviral protease * inhibitors * luminescent assay Subject RIV: CE - Biochemistry Impact factor: 2.670, year: 2005

Retroviral restriction and dependency factors in primates and carnivores

Science.gov (United States)

Fadel, Hind J.; Poeschla, Eric M.

2014-01-01

Recent studies have extended the rapidly developing retroviral restriction factor field to cells of carnivore species. Carnivoran genomes, and the domestic cat genome in particular, are revealing intriguing properties vis-à;-vis the primate and feline lentiviruses, not only with respect to their repertoires of virus-blocking restriction factors but also replication-enabling dependency factors. Therapeutic application of restriction factors is envisioned for human immunodeficiency virus (HIV) disease and the feline immunodeficiency virus (FIV) model has promise for testing important hypotheses at the basic and translational level. Feline cell-tropic HIV-1 clones have also been generated by a strategy of restriction factor evasion. We review progress in this area in the context of what is known about retroviral restriction factors such as TRIM5alpha, TRIMCyp, APOBEC3 proteins and BST-2/Tetherin. PMID:21715018

Retroviral-mediated gene transfer and expression of human phenylalanine hydroxylase in primary mouse hepatocytes

Energy Technology Data Exchange (ETDEWEB)

Peng, H.; Armentano, D.; Mackenzie-Graham, L.; Shen, R.F.; Darlington, G.; Ledley, F.D.; Woo, S.L.C. (Baylor College of Medicine, Houston, TX (USA))

1988-11-01

Genetic therapy for phenylketonuria (severe phenylalanine hydroxylase deficiency) may require introduction of a normal phenylalanine hydroxylase gene into hepatic cells of patients. The authors report development of a recombinant retrovirus based on the N2 vector for gene transfer and expression of human phenylalanine hydroxylase cDNA in primary mouse hepatocytes. This construct contains an internal promoter of the human {alpha}{sub 1}-antitrypsin gene driving transcription of the phenylalanine hydroxylase cDNA. Primary mouse hepatocytes were isolated from newborn mice, infected with the recombinant virus, and selected for expression of the neomycin-resistance gene. Hepatocytes transformed with the recombinant virus contained high levels of human phenylalanine hydroxylase mRNA transcripts originating from the retroviral and internal promoters. These results demonstrate that the transcriptional regulatory elements of the {alpha}{sub 1} antitrypsin gene retain their tissue-specific function in the recombinant provirus and establish a method for efficient transfer and high-level expression of human phenylalanine hydroxylase in primary hepatocytes.

Retroviral-mediated gene transfer and expression of human phenylalanine hydroxylase in primary mouse hepatocytes

International Nuclear Information System (INIS)

Peng, H.; Armentano, D.; Mackenzie-Graham, L.; Shen, R.F.; Darlington, G.; Ledley, F.D.; Woo, S.L.C.

1988-01-01

Genetic therapy for phenylketonuria (severe phenylalanine hydroxylase deficiency) may require introduction of a normal phenylalanine hydroxylase gene into hepatic cells of patients. The authors report development of a recombinant retrovirus based on the N2 vector for gene transfer and expression of human phenylalanine hydroxylase cDNA in primary mouse hepatocytes. This construct contains an internal promoter of the human α 1 -antitrypsin gene driving transcription of the phenylalanine hydroxylase cDNA. Primary mouse hepatocytes were isolated from newborn mice, infected with the recombinant virus, and selected for expression of the neomycin-resistance gene. Hepatocytes transformed with the recombinant virus contained high levels of human phenylalanine hydroxylase mRNA transcripts originating from the retroviral and internal promoters. These results demonstrate that the transcriptional regulatory elements of the α 1 antitrypsin gene retain their tissue-specific function in the recombinant provirus and establish a method for efficient transfer and high-level expression of human phenylalanine hydroxylase in primary hepatocytes

Application of Live-Cell RNA Imaging Techniques to the Study of Retroviral RNA Trafficking

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Darrin V. Bann

2012-06-01

Full Text Available Retroviruses produce full-length RNA that serves both as a genomic RNA (gRNA, which is encapsidated into virus particles, and as an mRNA, which directs the synthesis of viral structural proteins. However, we are only beginning to understand the cellular and viral factors that influence trafficking of retroviral RNA and the selection of the RNA for encapsidation or translation. Live cell imaging studies of retroviral RNA trafficking have provided important insight into many aspects of the retrovirus life cycle including transcription dynamics, nuclear export of viral RNA, translational regulation, membrane targeting, and condensation of the gRNA during virion assembly. Here, we review cutting-edge techniques to visualize single RNA molecules in live cells and discuss the application of these systems to studying retroviral RNA trafficking.

Anti-retroviral therapy-induced status epilepticus in "pseudo-HIV serodeconversion".

Science.gov (United States)

Etgen, Thorleif; Eberl, Bernhard; Freudenberger, Thomas

2010-01-01

Diligence in the interpretation of results is essential as information gained from the psychiatric patient's history might often be restricted. Nonobservance of established guidelines may lead to a wrong diagnosis, induce a false therapy and result in life-threatening situations. Communication errors between hospitals and doctors and uncritical acceptance of prior diagnoses add substantially to this problem. We present a patient with alcohol-related dementia who received anti-retroviral therapy that promoted a non-convulsive status epilepticus. HIV serodeconversion was considered after our laboratory result yielded a HIV-negative status. Critical review of previous diagnostic investigations revealed several errors in the diagnosis of HIV infection leading to a "pseudo-serodeconversion." Finally, anti-retroviral therapy could be discontinued. Copyright © 2010 Elsevier Inc. All rights reserved.

The impact of envelope glycoprotein cleavage on the antigenicity, infectivity, and neutralization sensitivity of Env-pseudotyped human immunodeficiency virus type 1 particles

International Nuclear Information System (INIS)

Herrera, Carolina; Klasse, Per Johan; Michael, Elizabeth; Kake, Shivani; Barnes, Kelly; Kibler, Christopher W.; Campbell-Gardener, Lila; Si, Zhihai; Sodroski, Joseph; Moore, John P.; Beddows, Simon

2005-01-01

Endoproteolytic processing of the human immunodeficiency virus type 1 (HIV-1) envelope (Env) glycoproteins is an obligate part of the biosynthetic pathway that generates functional, fusion-competent Env complexes, which are then incorporated into infectious virions. We have examined the influence of cleavage on Env-specific antibody reactivity, Env incorporation into pseudovirions, and the infectivity and neutralization sensitivity of Env-pseudotyped viruses. To do so, we have used both incompletely processed wild-type (Wt) Env and engineered, cleavage-defective Env mutants. We find that there is no simple association between antibody reactivity to cell surface-expressed Env, and the ability of the same antibody to neutralize virus pseudotyped with the same Env proteins. One explanation for the absence of such an association is the diverse array of Env species present on the surface of transiently transfected cells. We also confirm that cleavage-defective mutants are antigenically different from Wt Env. These findings have implications for the use of Env binding assays as predictors of neutralizing activity, and for the development of cleavage-defective Env trimers for use as subunit immunogens

Hepatorenal correction in murine glycogen storage disease type I with a double-stranded adeno-associated virus vector.

LENUS (Irish Health Repository)

Luo, Xiaoyan

2011-11-01

Glycogen storage disease type Ia (GSD-Ia) is caused by the deficiency of glucose-6-phosphatase (G6Pase). Long-term complications of GSD-Ia include life-threatening hypoglycemia and proteinuria progressing to renal failure. A double-stranded (ds) adeno-associated virus serotype 2 (AAV2) vector encoding human G6Pase was pseudotyped with four serotypes, AAV2, AAV7, AAV8, and AAV9, and we evaluated efficacy in 12-day-old G6pase (-\\/-) mice. Hypoglycemia during fasting (plasma glucose <100 mg\\/dl) was prevented for >6 months by the dsAAV2\\/7, dsAAV2\\/8, and dsAAV2\\/9 vectors. Prolonged fasting for 8 hours revealed normalization of blood glucose following dsAAV2\\/9 vector administration at the higher dose. The glycogen content of kidney was reduced by >65% with both the dsAAV2\\/7 and dsAAV2\\/9 vectors, and renal glycogen content was stably reduced between 7 and 12 months of age for the dsAAV2\\/9 vector-treated mice. Every vector-treated group had significantly reduced glycogen content in the liver, in comparison with untreated G6pase (-\\/-) mice. G6Pase was expressed in many renal epithelial cells of with the dsAAV2\\/9 vector for up to 12 months. Albuminuria and renal fibrosis were reduced by the dsAAV2\\/9 vector. Hepatorenal correction in G6pase (-\\/-) mice demonstrates the potential of AAV vectors for the correction of inherited diseases of metabolism.

Nurses' perceptions about Botswana patients' anti-retroviral therapy ...

African Journals Online (AJOL)

Anti-retroviral drugs(ARVs) are supplied free of charge in Botswana. Lifelong adherence to antiretroviral therapy (ART) is vital to improve the patient's state of well-being and to prevent the development of strains of the human immunodefi ciency virus (HIV) that are resistant to ART. Persons with ART-resistant strains of HIV ...

The host cell sulfonation pathway contributes to retroviral infection at a step coincident with provirus establishment.

Directory of Open Access Journals (Sweden)

James W Bruce

2008-11-01

Full Text Available The early steps of retrovirus replication leading up to provirus establishment are highly dependent on cellular processes and represent a time when the virus is particularly vulnerable to antivirals and host defense mechanisms. However, the roles played by cellular factors are only partially understood. To identify cellular processes that participate in these critical steps, we employed a high volume screening of insertionally mutagenized somatic cells using a murine leukemia virus (MLV vector. This approach identified a role for 3'-phosphoadenosine 5'-phosphosulfate synthase 1 (PAPSS1, one of two enzymes that synthesize PAPS, the high energy sulfate donor used in all sulfonation reactions catalyzed by cellular sulfotransferases. The role of the cellular sulfonation pathway was confirmed using chemical inhibitors of PAPS synthases and cellular sulfotransferases. The requirement for sulfonation was mapped to a stage during or shortly after MLV provirus establishment and influenced subsequent gene expression from the viral long terminal repeat (LTR promoter. Infection of cells by an HIV vector was also shown to be highly dependent on the cellular sulfonation pathway. These studies have uncovered a heretofore unknown regulatory step of retroviral replication, have defined a new biological function for sulfonation in nuclear gene expression, and provide a potentially valuable new target for HIV/AIDS therapy.

Patients' perceptions of a rural decentralised anti-retroviral therapy ...

African Journals Online (AJOL)

Background: Geographical and financial barriers hamper accessibility to HIV services for rural communities. The government has introduced the nurse initiated management of anti-retroviral therapy at primary health care level, in an effort to improve patient access and reduce patient loads on facilities further up the system.

Concise classification of the genomic porcine endogenous retroviral gamma1 load to defined lineages.

Science.gov (United States)

Klymiuk, Nikolai; Wolf, Eckhard; Aigner, Bernhard

2008-02-05

We investigated the infection history of porcine endogenous retroviruses (PERV) gamma1 by analyzing published env and LTR sequences. PERV sequences from various breeds, porcine cell lines and infected human primary cells were included in the study. We identified a considerable number of retroviral lineages indicating multiple independent colonization events of the porcine genome. A recent boost of the proviral load in an isolated pig herd and exclusive occurrence of distinct lineages in single studies indicated the ongoing colonization of the porcine genome with endogenous retroviruses. Retroviral recombination between co-packaged genomes was a general factor for PERV gamma1 diversity which indicated the simultaneous expression of different proviral loci over a period of time. In total, our detailed description of endogenous retroviral lineages is the prerequisite for breeding approaches to minimize the infectious potential of porcine tissues for the subsequent use in xenotransplantation.

Pregnancy outcome of HIV-infected women on anti-retroviral therapy ...

African Journals Online (AJOL)

... received anti-retroviral treatment at the University of Port Harcourt Teaching Hospital ... 3.8% started in 2nd trimester of pregnancy and 14.1% during labour. ... was minimal and stresses the value of antiretroviral treatment in the prevention of ...

Modulating ectopic gene expression levels by using retroviral vectors equipped with synthetic promoters

OpenAIRE

Ferreira, Joshua P.; Peacock, Ryan W. S.; Lawhorn, Ingrid E. B.; Wang, Clifford L.

2011-01-01

The human cytomegalovirus and elongation factor 1α promoters are constitutive promoters commonly employed by mammalian expression vectors. These promoters generally produce high levels of expression in many types of cells and tissues. To generate a library of synthetic promoters capable of generating a range of low, intermediate, and high expression levels, the TATA and CAAT box elements of these promoters were mutated. Other promoter variants were also generated by random mutagenesis. Evalua...

Retroviral integration: Site matters

Science.gov (United States)

Demeulemeester, Jonas; De Rijck, Jan

2015-01-01

Here, we review genomic target site selection during retroviral integration as a multistep process in which specific biases are introduced at each level. The first asymmetries are introduced when the virus takes a specific route into the nucleus. Next, by co‐opting distinct host cofactors, the integration machinery is guided to particular chromatin contexts. As the viral integrase captures a local target nucleosome, specific contacts introduce fine‐grained biases in the integration site distribution. In vivo, the established population of proviruses is subject to both positive and negative selection, thereby continuously reshaping the integration site distribution. By affecting stochastic proviral expression as well as the mutagenic potential of the virus, integration site choice may be an inherent part of the evolutionary strategies used by different retroviruses to maximise reproductive success. PMID:26293289

FLT3 ligand preserves the uncommitted CD34+CD38- progenitor cells during cytokine prestimulation for retroviral transduction

DEFF Research Database (Denmark)

Nielsen, S D; Husemoen, L L; Sørensen, T U

2000-01-01

for transduction of CD34+ cells. The effect of cytokine prestimulation on transduction efficiency and the population of uncommitted CD34+CD38- cells was determined. CD34+ cells harvested from umbilical cord blood were kept in suspension cultures and stimulated with combinations of the cytokines stem cell factor......Before stem cell gene therapy can be considered for clinical applications, problems regarding cytokine prestimulation remain to be solved. In this study, a retroviral vector carrying the genes for the enhanced version of green fluorescent protein (EGFP) and neomycin resistance (neo(r)) was used...... in a higher percentage of cells than the EGFP gene, but there seemed to be a positive correlation between expression of the two genes. The effect of cytokine prestimulation was therefore monitored using EGFP as marker for transduction. When SCF was compared to SCF in combination with more potent cytokines...

Vector Production in an Academic Environment: A Tool to Assess Production Costs

Science.gov (United States)

Boeke, Aaron; Doumas, Patrick; Reeves, Lilith; McClurg, Kyle; Bischof, Daniela; Sego, Lina; Auberry, Alisha; Tatikonda, Mohan

2013-01-01

Abstract Generating gene and cell therapy products under good manufacturing practices is a complex process. When determining the cost of these products, researchers must consider the large number of supplies used for manufacturing and the personnel and facility costs to generate vector and maintain a cleanroom facility. To facilitate cost estimates, the Indiana University Vector Production Facility teamed with the Indiana University Kelley School of Business to develop a costing tool that, in turn, provides pricing. The tool is designed in Microsoft Excel and is customizable to meet the needs of other core facilities. It is available from the National Gene Vector Biorepository. The tool allows cost determinations using three different costing methods and was developed in an effort to meet the A21 circular requirements for U.S. core facilities performing work for federally funded projects. The costing tool analysis reveals that the cost of vector production does not have a linear relationship with batch size. For example, increasing the production from 9 to18 liters of a retroviral vector product increases total costs a modest 1.2-fold rather than doubling in total cost. The analysis discussed in this article will help core facilities and investigators plan a cost-effective strategy for gene and cell therapy production. PMID:23360377

Efficient delivery and stable gene expression in a hematopoietic cell line using a chimeric serotype 35 fiber pseudotyped helper-dependent adenoviral vector

International Nuclear Information System (INIS)

Balamotis, Michael Andrew; Huang, Katie; Mitani, Kohnosuke

2004-01-01

Certain human cell populations have remained difficult to infect with human adenovirus (Ad) serotype 5 because of their lack of coxsackievirus B-adenovirus receptor (CAR). Native adenovirus fiber compositions, although diverse, cannot infect all tissue types. Recently, a chimeric Ad5/35 fiber was created, which displays an altered tropism from Ad5. We incorporated this chimeric fiber into a helper-dependent (HD) adenovirus vector system and compared HD to E1-deleted (E1Δ) vectors by transgene expression, cell transduction efficiency, and cytotoxicity. K562 cells were infected ∼50 times more efficiently with the chimeric Ad5/35 fiber compared with the Ad5 fiber. Short-term transgene expression was sustained longer from HD Ad5/35 than E1Δ Ad5/35 vector after in vitro infection of actively dividing K562 cells. Rapid loss of transgene expression from E1Δ Ad5/35 infection was not due to the loss of vector genomes, as determined by quantitative real-time PCR (QRT-PCR), or cytotoxicity, but rather through a putative silencing mechanism

Retroviral Gag protein-RNA interactions: Implications for specific genomic RNA packaging and virion assembly.

Science.gov (United States)

Olson, Erik D; Musier-Forsyth, Karin

2018-03-31

Retroviral Gag proteins are responsible for coordinating many aspects of virion assembly. Gag possesses two distinct nucleic acid binding domains, matrix (MA) and nucleocapsid (NC). One of the critical functions of Gag is to specifically recognize, bind, and package the retroviral genomic RNA (gRNA) into assembling virions. Gag interactions with cellular RNAs have also been shown to regulate aspects of assembly. Recent results have shed light on the role of MA and NC domain interactions with nucleic acids, and how they jointly function to ensure packaging of the retroviral gRNA. Here, we will review the literature regarding RNA interactions with NC, MA, as well as overall mechanisms employed by Gag to interact with RNA. The discussion focuses on human immunodeficiency virus type-1, but other retroviruses will also be discussed. A model is presented combining all of the available data summarizing the various factors and layers of selection Gag employs to ensure specific gRNA packaging and correct virion assembly. Copyright © 2018 Elsevier Ltd. All rights reserved.

Gaps in the Implementation of Anti-Retroviral Treatment: A Case for ...

African Journals Online (AJOL)

... of Anti-Retroviral Treatment: A Case for Addressing Gender and Mental Health ... to score successes in ensuring adherence to ART as well as reducing new HIV ... lack of established clinical infrastructure, negative social stigma and the cost ...

Gene therapy of Fanconi anemia: preclinical efficacy using lentiviral vectors.

Science.gov (United States)

Galimi, Francesco; Noll, Meenakshi; Kanazawa, Yoshiyuki; Lax, Timothy; Chen, Cindy; Grompe, Markus; Verma, Inder M

2002-10-15

Fanconi anemia (FA) is an inherited cancer susceptibility syndrome caused by mutations in a DNA repair pathway including at least 6 genes (FANCA, FANCC, FANCD2, FANCE, FANCF, and FANCG). The clinical course of the disease is dominated by progressive, life-threatening bone marrow failure and high incidence of acute myelogenous leukemia and solid tumors. Allogeneic bone marrow transplantation (BMT) is a therapeutic option but requires HLA-matched donors. Gene therapy holds great promise for FA, but previous attempts to use retroviral vectors in humans have proven ineffective given the impaired proliferation potential of human FA hematopoietic progenitors (HPCs). In this work, we show that using lentiviral vectors efficient genetic correction can be achieved in quiescent hematopoietic progenitors from Fanca(-/-) and Fancc(-/-) mice. Long-term repopulating HPCs were transduced by a single exposure of unfractionated bone marrow mononuclear cells to lentivectors carrying the normal gene. Notably, no cell purification or cytokine prestimulation was necessary. Resistance to DNA- damaging agents was fully restored by lentiviral transduction, allowing for in vivo selection of the corrected cells with nonablative doses of cyclophosphamide. This study strongly supports the use of lentiviral vectors for FA gene therapy in humans.

Changing T cell specificity by retroviral T cell receptor display

NARCIS (Netherlands)

Kessels, H. W.; van den Boom, M. D.; Spits, H.; Hooijberg, E.; Schumacher, T. N.

2000-01-01

The diversity of the T cell receptor (TCR) repertoire is limited, because of the processes of positive and negative T cell selection. To obtain T cells with specificities beyond the immune system's capacity, we have developed a strategy for retroviral TCR display. In this approach, a library of T

Lineage-specific expansions of retroviral insertions within the genomes of African great apes but not humans and orangutans.

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Chris T Yohn

2005-04-01

Full Text Available Retroviral infections of the germline have the potential to episodically alter gene function and genome structure during the course of evolution. Horizontal transmissions between species have been proposed, but little evidence exists for such events in the human/great ape lineage of evolution. Based on analysis of finished BAC chimpanzee genome sequence, we characterize a retroviral element (Pan troglodytes endogenous retrovirus 1 [PTERV1] that has become integrated in the germline of African great ape and Old World monkey species but is absent from humans and Asian ape genomes. We unambiguously map 287 retroviral integration sites and determine that approximately 95.8% of the insertions occur at non-orthologous regions between closely related species. Phylogenetic analysis of the endogenous retrovirus reveals that the gorilla and chimpanzee elements share a monophyletic origin with a subset of the Old World monkey retroviral elements, but that the average sequence divergence exceeds neutral expectation for a strictly nuclear inherited DNA molecule. Within the chimpanzee, there is a significant integration bias against genes, with only 14 of these insertions mapping within intronic regions. Six out of ten of these genes, for which there are expression data, show significant differences in transcript expression between human and chimpanzee. Our data are consistent with a retroviral infection that bombarded the genomes of chimpanzees and gorillas independently and concurrently, 3-4 million years ago. We speculate on the potential impact of such recent events on the evolution of humans and great apes.

Tailored HIV-1 vectors for genetic modification of primary human dendritic cells and monocytes.

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Durand, Stéphanie; Nguyen, Xuan-Nhi; Turpin, Jocelyn; Cordeil, Stephanie; Nazaret, Nicolas; Croze, Séverine; Mahieux, Renaud; Lachuer, Joël; Legras-Lachuer, Catherine; Cimarelli, Andrea

2013-01-01

Monocyte-derived dendritic cells (MDDCs) play a key role in the regulation of the immune system and are the target of numerous gene therapy applications. The genetic modification of MDDCs is possible with human immunodeficiency virus type 1 (HIV-1)-derived lentiviral vectors (LVs) but requires high viral doses to bypass their natural resistance to viral infection, and this in turn affects their physiological properties. To date, a single viral protein is able to counter this restrictive phenotype, Vpx, a protein derived from members of the HIV-2/simian immunodeficiency virus SM lineage that counters at least two restriction factors present in myeloid cells. By tagging Vpx with a short heterologous membrane-targeting domain, we have obtained HIV-1 LVs incorporating high levels of this protein (HIV-1-Src-Vpx). These vectors efficiently transduce differentiated MDDCs and monocytes either as previously purified populations or as populations within unsorted peripheral blood mononuclear cells (PBMCs). In addition, these vectors can be efficiently pseudotyped with receptor-specific envelopes, further restricting their cellular tropism almost uniquely to MDDCs. Compared to conventional HIV-1 LVs, these novel vectors allow for an efficient genetic modification of MDDCs and, more importantly, do not cause their maturation or affect their survival, which are unwanted side effects of the transduction process. This study describes HIV-1-Src-Vpx LVs as a novel potent tool for the genetic modification of differentiated MDDCs and of circulating monocyte precursors with strong potential for a wide range of gene therapy applications.

Inhibition of HIV-1 lentiviral particles infectivity by Gynostemma ...

African Journals Online (AJOL)

These claims motivated the study in which the inhibition of viral vector infectivity of HeLa cells was assessed flow cytometrically by measuring the expression of green fluorescent protein (GFP) transgene incorporated in the lentiviral vector construct. An infectious VSV-G-pseudotyped, human immunodeficiency virus type ...

Mesenchymal stromal cells retrovirally transduced with prodrug-converting genes are suitable vehicles for cancer gene therapy.

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Ďuriniková, E; Kučerová, L; Matúšková, M

2014-01-01

Mesenchymal stem/stromal cells (MSC) possess a set of several fairly unique properties which make them ideally suitable both for cellular therapies and regenerative medicine. These include: relative ease of isolation, the ability to differentiate along mesenchymal and non-mesenchymal lineages in vitro and the ability to be extensively expanded in culture without a loss of differentiative capacity. MSC are not only hypoimmunogenic, but they mediate immunosuppression upon transplantation, and possess pronounced anti-inflammatory properties. They are able to home to damaged tissues, tumors, and metastases following systemic administration. The ability of homing holds big promise for tumor-targeted delivery of therapeutic agents. Viruses are naturally evolved vehicles efficiently transferring their genes into host cells. This ability made them suitable for engineering vector systems for the delivery of genes of interest. MSC can be retrovirally transduced with genes encoding prodrug-converting genes (suicide genes), which are not toxic per se, but catalyze the formation of highly toxic metabolites following the application of a nontoxic prodrug. The homing ability of MSC holds advantages compared to virus vehicles which display many shortcomings in effective delivery of the therapeutic agents. Gene therapies mediated by viruses are limited by their restricted ability to track cancer cells infiltrating into the surrounding tissue, and by their low migratory capacity towards tumor. Thus combination of cellular therapy and gene delivery is an attractive option - it protects the vector from immune surveillance, and supports targeted delivery of a therapeutic gene/protein to the tumor site.

Manifestações otoneurológicas associadas à terapia anti-retroviral Otoneurological manifestations associated with antiretroviral therapy

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Andrêza Batista Cheloni Vieira

2008-02-01

Full Text Available Ototoxicidade e terapia anti-retroviral parecem estar associadas. O objetivo desse estudo foi avaliar essa possível correlação. Foram avaliados 779 prontuários médicos de pacientes infectados pelo HIV e regularmente acompanhados, sendo 162 tratados com terapia anti-retroviral e 122 não tratados (controle. Pacientes em tratamento eram mais velhos (média 42 anos, com maior tempo de confirmação sorológica (80 meses e com menor carga viral (p=0,00. CD4+ foi semelhante entre os grupos (P=0,60. No grupo tratado, três (1,8% casos de perda auditiva idiopática e dois (1,3% de perda auditiva relacionada a otosclerose foram observadas e ambas iniciadas após terapia anti-retroviral. Nenhuma diferença estatística relacionada à perda auditiva idiopática foi encontrada entre os grupos. Enquanto estudos descritivos consideram possível ototoxidade associada à terapia anti-retroviral, esse possível efeito adverso não foi relacionado à terapia anti-retroviral neste estudo. Contrariamente, otosclerose poderia estar correlacionada à terapia anti-retroviral. Este assunto merece ser estudado.Ototoxicity and antiretroviral therapy seem to be associated. The aim of this study was to evaluate this possible correlation. Evaluations were carried out on 779 medical records from HIV-infected patients who were being regularly followed up, of whom 162 were being treated with antiretroviral therapy and 122 were untreated (controls. The patients undergoing treatment were older (mean: 42 years, had had serological confirmation for longer times (80 months and had smaller viral loads (P = 0.00. CD4+ was similar between the groups (P = 0.60. In the treated group, three cases (1.8% of idiopathic hearing loss and two (1.3% of otosclerosis-related hearing loss were observed, which both started after antiretroviral therapy. No statistical difference relating to idiopathic hearing loss was found between the groups. While descriptive studies consider possible

Association of murine lupus and thymic full-length endogenous retroviral expression maps to a bone marrow stem cell

International Nuclear Information System (INIS)

Krieg, A.M.; Gourley, M.F.; Steinberg, A.D.

1991-01-01

Recent studies of thymic gene expression in murine lupus have demonstrated 8.4-kb (full-length size) modified polytropic (Mpmv) endogenous retroviral RNA. In contrast, normal control mouse strains do not produce detectable amounts of such RNA in their thymuses. Prior studies have attributed a defect in experimental tolerance in murine lupus to a bone marrow stem cell rather than to the thymic epithelium; in contrast, infectious retroviral expression has been associated with the thymic epithelium, rather than with the bone marrow stem cell. The present study was designed to determine whether the abnormal Mpmv expression associated with murine lupus mapped to thymic epithelium or to a marrow precursor. Lethally irradiated control and lupus-prone mice were reconstituted with T cell depleted bone marrow; one month later their thymuses were studied for endogenous retroviral RNA and protein expression. Recipients of bone marrow from nonautoimmune donors expressed neither 8.4-kb Mpmv RNA nor surface MCF gp70 in their thymuses. In contrast, recipients of bone marrow from autoimmune NZB or BXSB donors expressed thymic 8.4-kb Mpmv RNA and mink cell focus-forming gp70. These studies demonstrate that lupus-associated 8.4-kb Mpmv endogenous retroviral expression is determined by bone marrow stem cells

Generation of high-titer viral preparations by concentration using successive rounds of ultracentrifugation

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Ichim Christine V

2011-08-01

Full Text Available Abstract Background Viral vectors provide a method of stably introducing exogenous DNA into cells that are not easily transfectable allowing for the ectopic expression or silencing of genes for therapeutic or experimental purposes. However, some cell types, in particular bone marrow cells, dendritic cells and neurons are difficult to transduce with viral vectors. Successful transduction of such cells requires preparation of highly concentrated viral stocks, which permit a high virus concentration and multiplicity of infection (MOI during transduction. Pseudotyping with the vesicular stomatitis virus G (VSV-G envelope protein is common practice for both lentiviral and retroviral vectors. The VSV-G glycoprotein adds physical stability to retroviral particles, allowing concentration of virus by high-speed ultracentrifugation. Here we describe a method report for concentration of virus from large volumes of culture supernatant by means of successive rounds of ultracentrifugation into the same ultracentrifuge tube. Method Stable retrovirus producer cell lines were generated and large volumes of virus-containing supernatant were produced. We then tested the transduction ability of virus following varying rounds of concentration by ultra-centrifugation. In a second series of experiments lentivirus-containing supernatant was produced by transient transfection of 297T/17 cells and again we tested the transduction ability of virus following multiple rounds of ultra-centrifugation. Results We report being able to centrifuge VSV-G coated retrovirus for as many as four rounds of ultracentrifugation while observing an additive increase in viral titer. Even after four rounds of ultracentrifugation we did not reach a plateau in viral titer relative to viral supernatant concentrated to indicate that we had reached the maximum tolerated centrifugation time, implying that it may be possible to centrifuge VSV-G coated retrovirus even further should it be necessary

Good Laboratory Practice Preclinical Safety Studies for GSK2696273 (MLV Vector-Based Ex Vivo Gene Therapy for Adenosine Deaminase Deficiency Severe Combined Immunodeficiency) in NSG Mice.

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Carriglio, Nicola; Klapwijk, Jan; Hernandez, Raisa Jofra; Vezzoli, Michela; Chanut, Franck; Lowe, Rhiannon; Draghici, Elena; Nord, Melanie; Albertini, Paola; Cristofori, Patrizia; Richards, Jane; Staton, Hazel; Appleby, Jonathan; Aiuti, Alessandro; Sauer, Aisha V

2017-03-01

GSK2696273 (autologous CD34+ cells transduced with retroviral vector that encodes for the human adenosine deaminase [ADA] enzyme) is a gamma-retroviral ex vivo gene therapy of bone marrow-derived CD34+ cells for the treatment of adenosine deaminase deficiency severe combined immunodeficiency (ADA-SCID). ADA-SCID is a severe monogenic disease characterized by immunologic and nonimmunologic symptoms. Bone-marrow transplant from a matched related donor is the treatment of choice, but it is available for only a small proportion of patients. Ex vivo gene therapy of patient bone-marrow CD34+ cells is an alternative treatment. In order to prepare for a marketing authorization application in the European Union, preclinical safety studies in mice were requested by the European Medicines Agency (EMA). A pilot study and a main biodistribution study were performed according to Good Laboratory Practice (GLP) at the San Raffaele Telethon Institute for Gene Therapy test facility. In the main study, human umbilical cord blood (UCB)-derived CD34+ cells were transduced with gamma-retroviral vector used in the production of GSK2696273. Groups of 10 male and 10 female NOD-SCID gamma (NSG) mice were injected intravenously with a single dose of transduced- or mock-transduced UCB CD34+ cells, and they were observed for 4 months. Engraftment and multilineage differentiation of blood cells was observed in the majority of animals in both groups. There was no significant difference in the level of chimerism between the two groups. In the gene therapy group, vector was detectable in lymphohemopoietic and nonlymphohemopoietic tissues, consistent with the presence of gene-modified human hematopoietic donor cells. Given the absence of relevant safety concerns in the data, the nonclinical studies and the clinical experience with GSK2696273 supported a successful application for market authorization in the European Union for the treatment of ADA-SCID patients, for whom no suitable human leukocyte

[Mechanisms of retroviral immunosuppressive domain-induced immune modulation].

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Blinov, V M; Krasnov, G S; Shargunov, A V; Shurdov, M A; Zverev, V V

2013-01-01

Immunosuppressive domains (ISD) of viral envelope glycoproteins provide highly pathogenic phenotypes of various retroviruses. ISD interaction with immune cells leads to an inhibition of a response. In the 1980s it was shown that the fragment of ISD comprising of 17 amino acids (named CKS-17) is carrying out such immune modulation. However the underlying mechanisms were not known. The years of thorough research allowed to identify the regulation of Ras-Raf-MEK-MAPK and PI3K-AKT-mTOR cellular pathways as a result of ISD interaction with immune cells. By the way, this leads to decrease of secretion of stimulatory cytokines (e.g., IL-12) and increase of inhibitory, anti-inflammatory ones (e.g., IL-10). One of the receptor tyrosine kinases inducing signal in these pathways acts as the primary target of ISD while other key regulators--cAMP and diacylglycerol (DAG), act as secondary messengers of signal transduction. Immunosuppressive-like domains can be found not only in retroviruses; the presence of ISD within Ebola viral envelope glycoproteins caused extremely hard clinical course of virus-induced hemorrhagic fever. A number of retroviral-origin fragments encoding ISD can be found in the human genome. These regions are expressed in the placenta within genes of syncytins providing a tolerance of mother's immune system to an embryo. The present review is devoted to molecular aspects of retroviral ISD-induced modulation of host immune system.

Murine leukemia virus vector integration favors promoter regions and regional hot spots in a human T-cell line

International Nuclear Information System (INIS)

Tsukahara, Tomonori; Agawa, Hideyuki; Matsumoto, Sayori; Matsuda, Mizuho; Ueno, Shuichi; Yamashita, Yuki; Yamada, Koichiro; Tanaka, Nobuyuki; Kojima, Katsuhiko; Takeshita, Toshikazu

2006-01-01

Genomic analysis of integration will be important in evaluating the safety of human gene therapy with retroviral vectors. Here, we investigated MLV vector integration sites in human T-cells, since they are amenable to gene transfer studies, and have been used therapeutically in clinical trials. We mapped 340 MLV vector integration sites in the infected human T-cell clones we established. The data showed that MLV preferred integration near the transcription start sites (±5 kb), near CpG islands (±1 kb), and within the first intron of RefSeq genes. We also identified MLV integration hot spots that contained three or more integrations within a 100 kb region. RT-PCR revealed that mRNA-levels of T-cell clones that contained MLV integrations near transcription start sites or introns were dysregulated compared to the uninfected cells. These studies help define the profile of MLV integration in T-cells and the risks associated with MLV-based gene therapy

Large-scale manufacture and characterization of a lentiviral vector produced for clinical ex vivo gene therapy application.

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Merten, Otto-Wilhelm; Charrier, Sabine; Laroudie, Nicolas; Fauchille, Sylvain; Dugué, Céline; Jenny, Christine; Audit, Muriel; Zanta-Boussif, Maria-Antonietta; Chautard, Hélène; Radrizzani, Marina; Vallanti, Giuliana; Naldini, Luigi; Noguiez-Hellin, Patricia; Galy, Anne

2011-03-01

From the perspective of a pilot clinical gene therapy trial for Wiskott-Aldrich syndrome (WAS), we implemented a process to produce a lentiviral vector under good manufacturing practices (GMP). The process is based on the transient transfection of 293T cells in Cell Factory stacks, scaled up to harvest 50 liters of viral stock per batch, followed by purification of the vesicular stomatitis virus glycoprotein-pseudotyped particles through several membrane-based and chromatographic steps. The process leads to a 200-fold volume concentration and an approximately 3-log reduction in protein and DNA contaminants. An average yield of 13% of infectious particles was obtained in six full-scale preparations. The final product contained low levels of contaminants such as simian virus 40 large T antigen or E1A sequences originating from producer cells. Titers as high as 2 × 10(9) infectious particles per milliliter were obtained, generating up to 6 × 10(11) infectious particles per batch. The purified WAS vector was biologically active, efficiently expressing the genetic insert in WAS protein-deficient B cell lines and transducing CD34(+) cells. The vector introduced 0.3-1 vector copy per cell on average in CD34(+) cells when used at the concentration of 10(8) infectious particles per milliliter, which is comparable to preclinical preparations. There was no evidence of cellular toxicity. These results show the implementation of large-scale GMP production, purification, and control of advanced HIV-1-derived lentiviral technology. Results obtained with the WAS vector provide the initial manufacturing and quality control benchmarking that should be helpful to further development and clinical applications.

In vivo mitochondrial function in HIV-infected persons treated with contemporary anti-retroviral therapy: a magnetic resonance spectroscopy study.

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Brendan A I Payne

Full Text Available Modern anti-retroviral therapy is highly effective at suppressing viral replication and restoring immune function in HIV-infected persons. However, such individuals show reduced physiological performance and increased frailty compared with age-matched uninfected persons. Contemporary anti-retroviral therapy is thought to be largely free from neuromuscular complications, whereas several anti-retroviral drugs previously in common usage have been associated with mitochondrial toxicity. It has recently been established that patients with prior exposure to such drugs exhibit irreversible cellular and molecular mitochondrial defects. However the functional significance of such damage remains unknown. Here we use phosphorus magnetic resonance spectroscopy ((31P-MRS to measure in vivo muscle mitochondrial oxidative function, in patients treated with contemporary anti-retroviral therapy, and compare with biopsy findings (cytochrome c oxidase (COX histochemistry. We show that dynamic oxidative function (post-exertional ATP (adenosine triphosphate resynthesis was largely maintained in the face of mild to moderate COX defects (affecting up to ∼10% of fibers: τ½ ADP (half-life of adenosine diphosphate clearance, HIV-infected 22.1±9.9 s, HIV-uninfected 18.8±4.4 s, p = 0.09. In contrast, HIV-infected patients had a significant derangement of resting state ATP metabolism compared with controls: ADP/ATP ratio, HIV-infected 1.24±0.08×10(-3, HIV-uninfected 1.16±0.05×10(-3, p = 0.001. These observations are broadly reassuring in that they suggest that in vivo mitochondrial function in patients on contemporary anti-retroviral therapy is largely maintained at the whole organ level, despite histochemical (COX defects within individual cells. Basal energy requirements may nevertheless be increased.

Enhancers Are Major Targets for Murine Leukemia Virus Vector Integration

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De Ravin, Suk See; Su, Ling; Theobald, Narda; Choi, Uimook; Macpherson, Janet L.; Poidinger, Michael; Symonds, Geoff; Pond, Susan M.; Ferris, Andrea L.; Hughes, Stephen H.

2014-01-01

ABSTRACT Retroviral vectors have been used in successful gene therapies. However, in some patients, insertional mutagenesis led to leukemia or myelodysplasia. Both the strong promoter/enhancer elements in the long terminal repeats (LTRs) of murine leukemia virus (MLV)-based vectors and the vector-specific integration site preferences played an important role in these adverse clinical events. MLV integration is known to prefer regions in or near transcription start sites (TSS). Recently, BET family proteins were shown to be the major cellular proteins responsible for targeting MLV integration. Although MLV integration sites are significantly enriched at TSS, only a small fraction of the MLV integration sites (integration map of more than one million integration sites from CD34+ hematopoietic stem cells transduced with a clinically relevant MLV-based vector. The integration sites form ∼60,000 tight clusters. These clusters comprise ∼1.9% of the genome. The vast majority (87%) of the integration sites are located within histone H3K4me1 islands, a hallmark of enhancers. The majority of these clusters also have H3K27ac histone modifications, which mark active enhancers. The enhancers of some oncogenes, including LMO2, are highly preferred targets for integration without in vivo selection. IMPORTANCE We show that active enhancer regions are the major targets for MLV integration; this means that MLV preferentially integrates in regions that are favorable for viral gene expression in a variety of cell types. The results provide insights for MLV integration target site selection and also explain the high risk of insertional mutagenesis that is associated with gene therapy trials using MLV vectors. PMID:24501411

Evolution of endogenous non-retroviral genes integrated into plant genomes

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Hyosub Chu

2014-08-01

Full Text Available Numerous comparative genome analyses have revealed the wide extent of horizontal gene transfer (HGT in living organisms, which contributes to their evolution and genetic diversity. Viruses play important roles in HGT. Endogenous viral elements (EVEs are defined as viral DNA sequences present within the genomes of non-viral organisms. In eukaryotic cells, the majority of EVEs are derived from RNA viruses using reverse transcription. In contrast, endogenous non-retroviral elements (ENREs are poorly studied. However, the increasing availability of genomic data and the rapid development of bioinformatics tools have enabled the identification of several ENREs in various eukaryotic organisms. To date, a small number of ENREs integrated into plant genomes have been identified. Of the known non-retroviruses, most identified ENREs are derived from double-strand (ds RNA viruses, followed by single-strand (ss DNA and ssRNA viruses. At least eight virus families have been identified. Of these, viruses in the family Partitiviridae are dominant, followed by viruses of the families Chrysoviridae and Geminiviridae. The identified ENREs have been primarily identified in eudicots, followed by monocots. In this review, we briefly discuss the current view on non-retroviral sequences integrated into plant genomes that are associated with plant-virus evolution and their possible roles in antiviral resistance.

Phenotypic correction of Fanconi anemia cells in the murine bone marrow after carrier cell mediated delivery of lentiviral vector.

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Chakkaramakkil Verghese, Santhosh; Goloviznina, Natalya A; Kurre, Peter

2016-11-19

Fanconi anemia (FA) is an autosomal-recessive disorder associated with hematopoietic failure and it is a candidate for hematopoietic stem cell (HSC)-directed gene therapy. However, the characteristically reduced HSC numbers found in FA patients, their ineffective mobilization from the marrow, and re-oxygenation damage during ex vivo manipulation have precluded clinical success using conventional in vitro approaches. We previously demonstrated that lentiviral vector (LV) particles reversibly attach to the cell surface where they gain protection from serum complement neutralization. We reasoned that cellular delivery of LV to the bone marrow niche could avoid detrimental losses during FA HSC mobilization and in vitro modification. Here, we demonstrate that a VSV-G pseudotyped lentivector, carrying the FANCC transgene, can be transmitted from carrier to bystander cells. In cell culture and transplantation models of FA, we further demonstrate that LV carrier cells migrate along SDF-1α gradients and transfer vector particles that stably integrate and phenotypically correct the characteristic DNA alkylator sensitivity in murine and human FA-deficient target bystander cells. Altogether, we demonstrate that cellular homing mechanisms can be harnessed for the functional phenotype correction in murine FA hematopoietic cells.

Phenotypic correction of Fanconi anemia cells in the murine bone marrow after carrier cell mediated delivery of lentiviral vector

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Santhosh Chakkaramakkil Verghese

2016-11-01

Full Text Available Abstract Fanconi anemia (FA is an autosomal-recessive disorder associated with hematopoietic failure and it is a candidate for hematopoietic stem cell (HSC-directed gene therapy. However, the characteristically reduced HSC numbers found in FA patients, their ineffective mobilization from the marrow, and re-oxygenation damage during ex vivo manipulation have precluded clinical success using conventional in vitro approaches. We previously demonstrated that lentiviral vector (LV particles reversibly attach to the cell surface where they gain protection from serum complement neutralization. We reasoned that cellular delivery of LV to the bone marrow niche could avoid detrimental losses during FA HSC mobilization and in vitro modification. Here, we demonstrate that a VSV-G pseudotyped lentivector, carrying the FANCC transgene, can be transmitted from carrier to bystander cells. In cell culture and transplantation models of FA, we further demonstrate that LV carrier cells migrate along SDF-1α gradients and transfer vector particles that stably integrate and phenotypically correct the characteristic DNA alkylator sensitivity in murine and human FA-deficient target bystander cells. Altogether, we demonstrate that cellular homing mechanisms can be harnessed for the functional phenotype correction in murine FA hematopoietic cells.

VlincRNAs controlled by retroviral elements are a hallmark of pluripotency and cancer.

Science.gov (United States)

St Laurent, Georges; Shtokalo, Dmitry; Dong, Biao; Tackett, Michael R; Fan, Xiaoxuan; Lazorthes, Sandra; Nicolas, Estelle; Sang, Nianli; Triche, Timothy J; McCaffrey, Timothy A; Xiao, Weidong; Kapranov, Philipp

2013-07-22

The function of the non-coding portion of the human genome remains one of the most important questions of our time. Its vast complexity is exemplified by the recent identification of an unusual and notable component of the transcriptome - very long intergenic non-coding RNAs, termed vlincRNAs. Here we identify 2,147 vlincRNAs covering 10 percent of our genome. We show they are present not only in cancerous cells, but also in primary cells and normal human tissues, and are controlled by canonical promoters. Furthermore, vlincRNA promoters frequently originate from within endogenous retroviral sequences. Strikingly, the number of vlincRNAs expressed from endogenous retroviral promoters strongly correlates with pluripotency or the degree of malignant transformation. These results suggest a previously unknown connection between the pluripotent state and cancer via retroviral repeat-driven expression of vlincRNAs. Finally, we show that vlincRNAs can be syntenically conserved in humans and mouse and their depletion using RNAi can cause apoptosis in cancerous cells. These intriguing observations suggest that vlincRNAs could create a framework that combines many existing short ESTs and lincRNAs into a landscape of very long transcripts functioning in the regulation of gene expression in the nucleus. Certain types of vlincRNAs participate at specific stages of normal development and, based on analysis of a limited set of cancerous and primary cell lines, they appear to be co-opted by cancer-associated transcriptional programs. This provides additional understanding of transcriptome regulation during the malignant state, and could lead to additional targets and options for its reversal.

The prion protein has DNA strand transfer properties similar to retroviral nucleocapsid protein.

Science.gov (United States)

Gabus, C; Auxilien, S; Péchoux, C; Dormont, D; Swietnicki, W; Morillas, M; Surewicz, W; Nandi, P; Darlix, J L

2001-04-06

The transmissible spongiform encephalopathies are fatal neurodegenerative diseases that are associated with the accumulation of a protease-resistant form of the cellular prion protein (PrP). Although PrP is highly conserved and widely expressed in vertebrates, its function remains a matter of speculation. Indeed PrP null mice develop normally and are healthy. Recent results show that PrP binds to nucleic acids in vitro and is found associated with retroviral particles. Furthermore, in mice the scrapie infectious process appears to be accelerated by MuLV replication. These observations prompted us to further investigate the interaction between PrP and nucleic acids, and compare it with that of the retroviral nucleocapsid protein (NC). As the major nucleic acid-binding protein of the retroviral particle, NC protein is tightly associated with the genomic RNA in the virion nucleocapsid, where it chaperones proviral DNA synthesis by reverse transcriptase. Our results show that the human prion protein (huPrP) functionally resembles NCp7 of HIV-1. Both proteins form large nucleoprotein complexes upon binding to DNA. They accelerate the hybridization of complementary DNA strands and chaperone viral DNA synthesis during the minus and plus DNA strand transfers necessary to generate the long terminal repeats. The DNA-binding and strand transfer properties of huPrP appear to map to the N-terminal fragment comprising residues 23 to 144, whereas the C-terminal domain is inactive. These findings suggest that PrP could be involved in nucleic acid metabolism in vivo. Copyright 2001 Academic Press.

Alpharetroviral self-inactivating vectors produced by a superinfection-resistant stable packaging cell line allow genetic modification of primary human T lymphocytes.

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Labenski, Verena; Suerth, Julia D; Barczak, Elke; Heckl, Dirk; Levy, Camille; Bernadin, Ornellie; Charpentier, Emmanuelle; Williams, David A; Fehse, Boris; Verhoeyen, Els; Schambach, Axel

2016-08-01

Primary human T lymphocytes represent an important cell population for adoptive immunotherapies, including chimeric-antigen and T-cell receptor applications, as they have the capability to eliminate non-self, virus-infected and tumor cells. Given the increasing numbers of clinical immunotherapy applications, the development of an optimal vector platform for genetic T lymphocyte engineering, which allows cost-effective high-quality vector productions, remains a critical goal. Alpharetroviral self-inactivating vectors (ARV) have several advantages compared to other vector platforms, including a more random genomic integration pattern and reduced likelihood for inducing aberrant splicing of integrated proviruses. We developed an ARV platform for the transduction of primary human T lymphocytes. We demonstrated functional transgene transfer using the clinically relevant herpes-simplex-virus thymidine kinase variant TK.007. Proof-of-concept of alpharetroviral-mediated T-lymphocyte engineering was shown in vitro and in a humanized transplantation model in vivo. Furthermore, we established a stable, human alpharetroviral packaging cell line in which we deleted the entry receptor (SLC1A5) for RD114/TR-pseudotyped ARVs to prevent superinfection and enhance genomic integrity of the packaging cell line and viral particles. We showed that superinfection can be entirely prevented, while maintaining high recombinant virus titers. Taken together, this resulted in an improved production platform representing an economic strategy for translating the promising features of ARVs for therapeutic T-lymphocyte engineering. Copyright © 2016 Elsevier Ltd. All rights reserved.

Deletion of the LTR enhancer/promoter has no impact on the integration profile of MLV vectors in human hematopoietic progenitors.

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Arianna Moiani

Full Text Available Moloney murine leukemia virus (MLV-derived gamma-retroviral vectors integrate preferentially near transcriptional regulatory regions in the human genome, and are associated with a significant risk of insertional gene deregulation. Self-inactivating (SIN vectors carry a deletion of the U3 enhancer and promoter in the long terminal repeat (LTR, and show reduced genotoxicity in pre-clinical assays. We report a high-definition analysis of the integration preferences of a SIN MLV vector compared to a wild-type-LTR MLV vector in the genome of CD34(+ human hematopoietic stem/progenitor cells (HSPCs. We sequenced 13,011 unique SIN-MLV integration sites and compared them to 32,574 previously generated MLV sites in human HSPCs. The SIN-MLV vector recapitulates the integration pattern observed for MLV, with the characteristic clustering of integrations around enhancer and promoter regions associated to H3K4me3 and H3K4me1 histone modifications, specialized chromatin configurations (presence of the H2A.Z histone variant and binding of RNA Pol II. SIN-MLV and MLV integration clusters and hot spots overlap in most cases and are generated at a comparable frequency, indicating that the reduced genotoxicity of SIN-MLV vectors in hematopoietic cells is not due to a modified integration profile.

Anti-Retroviral Lectins Have Modest Effects on Adherence of Trichomonas vaginalis to Epithelial Cells In Vitro and on Recovery of Tritrichomonas foetus in a Mouse Vaginal Model

Science.gov (United States)

Chatterjee, Aparajita; Ratner, Daniel M.; Ryan, Christopher M.; Johnson, Patricia J.; O’Keefe, Barry R.; Secor, W. Evan; Anderson, Deborah J.; Robbins, Phillips W.; Samuelson, John

2015-01-01

Trichomonas vaginalis causes vaginitis and increases the risk of HIV transmission by heterosexual sex, while Tritrichomonas foetus causes premature abortion in cattle. Our goals were to determine the effects, if any, of anti-retroviral lectins, which are designed to prevent heterosexual transmission of HIV, on adherence of Trichomonas to ectocervical cells and on Tritrichomonas infections in a mouse model. We show that Trichomonas Asn-linked glycans (N-glycans), like those of HIV, bind the mannose-binding lectin (MBL) that is part of the innate immune system. N-glycans of Trichomonas and Tritrichomonas bind anti-retroviral lectins (cyanovirin-N and griffithsin) and the 2G12 monoclonal antibody, each of which binds HIV N-glycans. Binding of cyanovirin-N appears to be independent of susceptibility to metronidazole, the major drug used to treat Trichomonas. Anti-retroviral lectins, MBL, and galectin-1 cause Trichomonas to self-aggregate and precipitate. The anti-retroviral lectins also increase adherence of ricin-resistant mutants, which are less adherent than parent cells, to ectocervical cell monolayers and to organotypic EpiVaginal tissue cells. Topical application of either anti-retroviral lectins or yeast N-glycans decreases by 40 to 70% the recovery of Tritrichomonas from the mouse vagina. These results, which are explained by a few simple models, suggest that the anti-retroviral lectins have a modest potential for preventing or treating human infections with Trichomonas. PMID:26252012

Anti-Retroviral Lectins Have Modest Effects on Adherence of Trichomonas vaginalis to Epithelial Cells In Vitro and on Recovery of Tritrichomonas foetus in a Mouse Vaginal Model.

Directory of Open Access Journals (Sweden)

Aparajita Chatterjee

Full Text Available Trichomonas vaginalis causes vaginitis and increases the risk of HIV transmission by heterosexual sex, while Tritrichomonas foetus causes premature abortion in cattle. Our goals were to determine the effects, if any, of anti-retroviral lectins, which are designed to prevent heterosexual transmission of HIV, on adherence of Trichomonas to ectocervical cells and on Tritrichomonas infections in a mouse model. We show that Trichomonas Asn-linked glycans (N-glycans, like those of HIV, bind the mannose-binding lectin (MBL that is part of the innate immune system. N-glycans of Trichomonas and Tritrichomonas bind anti-retroviral lectins (cyanovirin-N and griffithsin and the 2G12 monoclonal antibody, each of which binds HIV N-glycans. Binding of cyanovirin-N appears to be independent of susceptibility to metronidazole, the major drug used to treat Trichomonas. Anti-retroviral lectins, MBL, and galectin-1 cause Trichomonas to self-aggregate and precipitate. The anti-retroviral lectins also increase adherence of ricin-resistant mutants, which are less adherent than parent cells, to ectocervical cell monolayers and to organotypic EpiVaginal tissue cells. Topical application of either anti-retroviral lectins or yeast N-glycans decreases by 40 to 70% the recovery of Tritrichomonas from the mouse vagina. These results, which are explained by a few simple models, suggest that the anti-retroviral lectins have a modest potential for preventing or treating human infections with Trichomonas.

Retroviral rebound syndrome after treatment discontinuation in a 15 year old girl with HIV attracted through mother-to-child transmission: case report

OpenAIRE

Gisslén Magnus; Friman Vanda

2007-01-01

Abstract A case of a 15 year old girl with retroviral rebound syndrome after discontinuation of highly active antiretroviral treatment (HAART) due to side effects is presented. The patient was transmitted with HIV at birth by her mother. She had recovered from severe AIDS after HAART was initiated five years earlier. This is the first case reported in the literature of retroviral rebound syndrome in a vertically transmitted HIV-infected patient.

Novel cyclo-peptides inhibit Ebola pseudotyped virus entry by targeting primed GP protein.

Science.gov (United States)

Li, Quanjie; Ma, Ling; Yi, Dongrong; Wang, Han; Wang, Jing; Zhang, Yongxin; Guo, Ying; Li, Xiaoyu; Zhou, Jinming; Shi, Yi; Gao, George F; Cen, Shan

2018-07-01

Ebola virus (EBOV) causes fatal hemorrhagic fever with high death rates in human. Currently, there are no available clinically-approved prophylactic or therapeutic treatments. The recently solved crystal structure of cleavage-primed EBOV glycoprotein (GPcl) in complex with the C domain of endosomal protein Niemann-Pick C1 (NPC1) provides a new target for the development of EBOV entry inhibitors. In this work, a computational approach using docking and molecular dynamic simulations is carried out for the rational design of peptide inhibitors. A novel cyclo-peptide (Pep-3.3) was identified to target at the late stage of EBOV entry and exhibit specific inhibitory activity against EBOV-GP pseudotyped viruses, with 50% inhibitory concentration (IC50) of 5.1 μM. In vitro binding assay and molecular simulations revealed that Pep-3.3 binds to GPcl with a KD value of 69.7 μM, through interacting with predicted residues in the hydrophobic binding pocket of GPcl. Mutation of predicted residues T83 caused resistance to Pep-3.3 inhibition in viral infectivity, providing preliminary support for the model of the peptide binding to GPcl. This study demonstrates the feasibility of inhibiting EBOV entry by targeting GPcl with peptides. Copyright © 2018 Elsevier B.V. All rights reserved.

Measles virus envelope pseudotyped lentiviral vectors transduce quiescent human HSCs at an efficiency without precedent.

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Lévy, Camille; Amirache, Fouzia; Girard-Gagnepain, Anais; Frecha, Cecilia; Roman-Rodríguez, Francisco J; Bernadin, Ornellie; Costa, Caroline; Nègre, Didier; Gutierrez-Guerrero, Alejandra; Vranckx, Lenard S; Clerc, Isabelle; Taylor, Naomi; Thielecke, Lars; Cornils, Kerstin; Bueren, Juan A; Rio, Paula; Gijsbers, Rik; Cosset, François-Loïc; Verhoeyen, Els

2017-10-24

Hematopoietic stem cell (HSC)-based gene therapy trials are now moving toward the use of lentiviral vectors (LVs) with success. However, one challenge in the field remains: efficient transduction of HSCs without compromising their stem cell potential. Here we showed that measles virus glycoprotein-displaying LVs (hemagglutinin and fusion protein LVs [H/F-LVs]) were capable of transducing 100% of early-acting cytokine-stimulated human CD34 + (hCD34 + ) progenitor cells upon a single application. Strikingly, these H/F-LVs also allowed transduction of up to 70% of nonstimulated quiescent hCD34 + cells, whereas conventional vesicular stomatitis virus G (VSV-G)-LVs reached 5% at the most with H/F-LV entry occurring exclusively through the CD46 complement receptor. Importantly, reconstitution of NOD/SCIDγc -/- (NSG) mice with H/F-LV transduced prestimulated or resting hCD34 + cells confirmed these high transduction levels in all myeloid and lymphoid lineages. Remarkably, for resting CD34 + cells, secondary recipients exhibited increasing transduction levels of up to 100%, emphasizing that H/F-LVs efficiently gene-marked HSCs in the resting state. Because H/F-LVs promoted ex vivo gene modification of minimally manipulated CD34 + progenitors that maintained stemness, we assessed their applicability in Fanconi anemia, a bone marrow (BM) failure with chromosomal fragility. Notably, only H/F-LVs efficiently gene-corrected minimally stimulated hCD34 + cells in unfractionated BM from these patients. These H/F-LVs improved HSC gene delivery in the absence of cytokine stimulation while maintaining their stem cell potential. Thus, H/F-LVs will facilitate future clinical applications requiring HSC gene modification, including BM failure syndromes, for which treatment has been very challenging up to now.

Membrane interaction of retroviral Gag proteins

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Robert Alfred Dick

2014-04-01

Full Text Available Assembly of an infectious retroviral particle relies on multimerization of the Gag polyprotein at the inner leaflet of the plasma membrane. The three domains of Gag common to all retroviruses-- MA, CA, and NC-- provide the signals for membrane binding, assembly, and viral RNA packaging, respectively. These signals do not function independently of one another. For example, Gag multimerization enhances membrane binding and is more efficient when NC is interacting with RNA. MA binding to the plasma membrane is governed by several principles, including electrostatics, recognition of specific lipid head groups, hydrophobic interactions, and membrane order. HIV-1 uses many of these principles while Rous sarcoma virus (RSV appears to use fewer. This review describes the principles that govern Gag interactions with membranes, focusing on RSV and HIV-1 Gag. The review also defines lipid and membrane behavior, and discusses the complexities in determining how lipid and membrane behavior impact Gag membrane binding.

Identification of endogenous retroviral reading frames in the human genome

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Wiuf Carsten

2004-10-01

Full Text Available Abstract Background Human endogenous retroviruses (HERVs comprise a large class of repetitive retroelements. Most HERVs are ancient and invaded our genome at least 25 million years ago, except for the evolutionary young HERV-K group. The far majority of the encoded genes are degenerate due to mutational decay and only a few non-HERV-K loci are known to retain intact reading frames. Additional intact HERV genes may exist, since retroviral reading frames have not been systematically annotated on a genome-wide scale. Results By clustering of hits from multiple BLAST searches using known retroviral sequences we have mapped 1.1% of the human genome as retrovirus related. The coding potential of all identified HERV regions were analyzed by annotating viral open reading frames (vORFs and we report 7836 loci as verified by protein homology criteria. Among 59 intact or almost-intact viral polyproteins scattered around the human genome we have found 29 envelope genes including two novel gammaretroviral types. One encodes a protein similar to a recently discovered zebrafish retrovirus (ZFERV while another shows partial, C-terminal, homology to Syncytin (HERV-W/FRD. Conclusions This compilation of HERV sequences and their coding potential provide a useful tool for pursuing functional analysis such as RNA expression profiling and effects of viral proteins, which may, in turn, reveal a role for HERVs in human health and disease. All data are publicly available through a database at http://www.retrosearch.dk.

Sex-specific aspects of endogenous retroviral insertion and deletion.

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Gemmell, Patrick; Hein, Jotun; Katzourakis, Aris

2013-11-07

We wish to understand how sex and recombination affect endogenous retroviral insertion and deletion. While theory suggests that the risk of ectopic recombination will limit the accumulation of repetitive DNA in areas of high meiotic recombination, the experimental evidence so far has been inconsistent. Under the assumption of neutrality, we examine the genomes of eighteen species of animal in order to compute the ratio of solo-LTRs that derive from insertions occurring down the male germ line as opposed to the female one (male bias). We also extend the simple idea of comparing autosome to allosome in order to predict the ratio of full-length proviruses we would expect to see under conditions of recombination linked deletion or otherwise. Using our model, we predict the ratio of allosomal to autosomal full-length proviruses to lie between32 and 23 under increasing male bias in mammals and between 1 and 2 under increasing male bias in birds. In contrast to our expectations, we find that a pattern of male bias is not universal across species and that there is a frequent overabundance of full-length proviruses on the allosome beyond the ratios predicted by our model. We use our data as a whole to argue that full-length proviruses should be treated as deleterious mutations or as effectively neutral mutations whose persistence in a full-length state is linked to the rate of meiotic recombination and whose origin is not universally male biased. These conclusions suggest that retroviral insertions on the allosome may be more prolific and that it might be possible to identify mechanisms of replication that are enhanced in the female sex.

The role of S-S bridge in retroviral protease function and virion maturation

Czech Academy of Sciences Publication Activity Database

Zábranská, Helena; Tůma, R.; Kluh, Ivan; Svatoš, A.; Ruml, Tomáš; Hrabal, R.; Pichová, Iva

2007-01-01

Roč. 365, č. 5 (2007), s. 1493-1504 ISSN 0022-2836 R&D Projects: GA MŠk 1M0508; GA MŠk 1M0520; GA ČR GESCO/06/E001 Institutional research plan: CEZ:AV0Z40550506 Keywords : retroviral protease * Mason-Pfizer monkey virus * disulfide * dimerization Subject RIV: CE - Biochemistry Impact factor: 4.472, year: 2007

Validation of an automated system for aliquoting of HIV-1 Env-pseudotyped virus stocks.

Science.gov (United States)

Schultz, Anke; Germann, Anja; Fuss, Martina; Sarzotti-Kelsoe, Marcella; Ozaki, Daniel A; Montefiori, David C; Zimmermann, Heiko; von Briesen, Hagen

2018-01-01

The standardized assessments of HIV-specific immune responses are of main interest in the preclinical and clinical stage of HIV-1 vaccine development. In this regard, HIV-1 Env-pseudotyped viruses play a central role for the evaluation of neutralizing antibody profiles and are produced according to Good Clinical Laboratory Practice- (GCLP-) compliant manual and automated procedures. To further improve and complete the automated production cycle an automated system for aliquoting HIV-1 pseudovirus stocks has been implemented. The automation platform consists of a modified Tecan-based system including a robot platform for handling racks containing 48 cryovials, a Decapper, a tubing pump and a safety device consisting of ultrasound sensors for online liquid level detection of each individual cryovial. With the aim to aliquot the HIV-1 pseudoviruses in an automated manner under GCLP-compliant conditions a validation plan was developed where the acceptance criteria-accuracy, precision as well as the specificity and robustness-were defined and summarized. By passing the validation experiments described in this article the automated system for aliquoting has been successfully validated. This allows the standardized and operator independent distribution of small-scale and bulk amounts of HIV-1 pseudovirus stocks with a precise and reproducible outcome to support upcoming clinical vaccine trials.

Alteration of blood-brain barrier integrity by retroviral infection.

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Philippe V Afonso

2008-11-01

Full Text Available The blood-brain barrier (BBB, which forms the interface between the blood and the cerebral parenchyma, has been shown to be disrupted during retroviral-associated neuromyelopathies. Human T Lymphotropic Virus (HTLV-1 Associated Myelopathy/Tropical Spastic Paraparesis (HAM/TSP is a slowly progressive neurodegenerative disease associated with BBB breakdown. The BBB is composed of three cell types: endothelial cells, pericytes and astrocytes. Although astrocytes have been shown to be infected by HTLV-1, until now, little was known about the susceptibility of BBB endothelial cells to HTLV-1 infection and the impact of such an infection on BBB function. We first demonstrated that human cerebral endothelial cells express the receptors for HTLV-1 (GLUT-1, Neuropilin-1 and heparan sulfate proteoglycans, both in vitro, in a human cerebral endothelial cell line, and ex vivo, on spinal cord autopsy sections from HAM/TSP and non-infected control cases. In situ hybridization revealed HTLV-1 transcripts associated with the vasculature in HAM/TSP. We were able to confirm that the endothelial cells could be productively infected in vitro by HTLV-1 and that blocking of either HSPGs, Neuropilin 1 or Glut1 inhibits this process. The expression of the tight-junction proteins within the HTLV-1 infected endothelial cells was altered. These cells were no longer able to form a functional barrier, since BBB permeability and lymphocyte passage through the monolayer of endothelial cells were increased. This work constitutes the first report of susceptibility of human cerebral endothelial cells to HTLV-1 infection, with implications for HTLV-1 passage through the BBB and subsequent deregulation of the central nervous system homeostasis. We propose that the susceptibility of cerebral endothelial cells to retroviral infection and subsequent BBB dysfunction is an important aspect of HAM/TSP pathogenesis and should be considered in the design of future therapeutics strategies.

Clonal Dominance With Retroviral Vector Insertions Near the ANGPT1 and ANGPT2 Genes in a Human Xenotransplant Mouse Model

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Reinhard Haemmerle

2014-01-01

Full Text Available Insertional leukemogenesis represents the major risk factor of hematopoietic stem cell (HSC based gene therapy utilizing integrating viral vectors. To develop a pre-clinical model for the evaluation of vector-related genotoxicity directly in the relevant human target cells, cord blood CD34+ HSCs were transplanted into immunodeficient NOD.SCID.IL2rg−/− (NSG mice after transduction with an LTR-driven gammaretroviral vector (GV. Furthermore, we specifically investigated the effect of prolonged in vitro culture in the presence of cytokines recently described to promote HSC expansion or maintenance. Clonality of human hematopoiesis in NSG mice was assessed by high throughput insertion site analyses and validated by insertion site-specific PCR depicting a GV typical integration profile with insertion sites resembling to 25% those of clinical studies. No overrepresentation of integrations in the vicinity of cancer-related genes was observed, however, several dominant clones were identified including two clones harboring integrations in the ANGPT1 and near the ANGPT2 genes associated with deregulated ANGPT1- and ANGPT2-mRNA levels. While these data underscore the potential value of the NSG model, our studies also identified short-comings such as overall low numbers of engrafted HSCs, limited in vivo observation time, and the challenges of in-depth insertion site analyses by low contribution of gene modified hematopoiesis.

Retroviral RNA Dimerization: From Structure to Functions

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Noé Dubois

2018-03-01

Full Text Available The genome of the retroviruses is a dimer composed by two homologous copies of genomic RNA (gRNA molecules of positive polarity. The dimerization process allows two gRNA molecules to be non-covalently linked together through intermolecular base-pairing. This step is critical for the viral life cycle and is highly conserved among retroviruses with the exception of spumaretroviruses. Furthermore, packaging of two gRNA copies into viral particles presents an important evolutionary advantage for immune system evasion and drug resistance. Recent studies reported RNA switches models regulating not only gRNA dimerization, but also translation and packaging, and a spatio-temporal characterization of viral gRNA dimerization within cells are now at hand. This review summarizes our current understanding on the structural features of the dimerization signals for a variety of retroviruses (HIVs, MLV, RSV, BLV, MMTV, MPMV…, the mechanisms of RNA dimer formation and functional implications in the retroviral cycle.

Retroviral expression screening of oncogenes in natural killer cell leukemia.

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Choi, Young Lim; Moriuchi, Ryozo; Osawa, Mitsujiro; Iwama, Atsushi; Makishima, Hideki; Wada, Tomoaki; Kisanuki, Hiroyuki; Kaneda, Ruri; Ota, Jun; Koinuma, Koji; Ishikawa, Madoka; Takada, Shuji; Yamashita, Yoshihiro; Oshimi, Kazuo; Mano, Hiroyuki

2005-08-01

Aggressive natural killer cell leukemia (ANKL) is an intractable malignancy that is characterized by the outgrowth of NK cells. To identify transforming genes in ANKL, we constructed a retroviral cDNA expression library from an ANKL cell line KHYG-1. Infection of 3T3 cells with recombinant retroviruses yielded 33 transformed foci. Nucleotide sequencing of the DNA inserts recovered from these foci revealed that 31 of them encoded KRAS2 with a glycine-to-alanine mutation at codon 12. Mutation-specific PCR analysis indicated that the KRAS mutation was present only in KHYG-1 cells, not in another ANKL cell line or in clinical specimens (n=8).

Mechanisms and factors that influence high frequency retroviral recombination

DEFF Research Database (Denmark)

Delviks-Frankenberry, Krista; Galli, Andrea; Nikolaitchik, Olga

2011-01-01

With constantly changing environmental selection pressures, retroviruses rely upon recombination to reassort polymorphisms in their genomes and increase genetic diversity, which improves the chances for the survival of their population. Recombination occurs during DNA synthesis, whereby reverse...... transcriptase undergoes template switching events between the two copackaged RNAs, resulting in a viral recombinant with portions of the genetic information from each parental RNA. This review summarizes our current understanding of the factors and mechanisms influencing retroviral recombination, fidelity...... of the recombination process, and evaluates the subsequent viral diversity and fitness of the progeny recombinant. Specifically, the high mutation rates and high recombination frequencies of HIV-1 will be analyzed for their roles in influencing HIV-1 global diversity, as well as HIV-1 diagnosis, drug treatment...

Application of HSVtk suicide gene to X-SCID gene therapy: Ganciclovir treatment offsets gene corrected X-SCID B cells

International Nuclear Information System (INIS)

Uchiyama, Toru; Kumaki, Satoru; Ishikawa, Yoshinori; Onodera, Masafumi; Sato, Miki; Du, Wei; Sasahara, Yoji; Tanaka, Nobuyuki; Sugamura, Kazuo; Tsuchiya, Shigeru

2006-01-01

Recently, a serious adverse effect of uncontrolled clonal T cell proliferation due to insertional mutagenesis of retroviral vector was reported in X-SCID gene therapy clinical trial. To offset the side effect, we have incorporated a suicide gene into therapeutic retroviral vector for selective elimination of transduced cells. In this study, B-cell lines from two X-SCID patients were transduced with bicistronic retroviral vector carrying human γc chain cDNA and Herpes simplex virus thymidine kinase gene. After confirmation of functional reconstitution of the γc chain, the cells were treated with ganciclovir (GCV). The γc chain positive cells were eliminated under low concentration without cytotoxicity on untransduced cells and have not reappeared at least for 5 months. Furthermore, the γc chain transduced cells were still sensitive to GCV after five months. These results demonstrated the efficacy of the suicide gene therapy although further in vivo studies are required to assess feasibility of this approach in clinical trial

HIV-1 anti-retroviral drug effect on the C. albicans hyphal growth rate by a Bio-Cell Tracer system Efeito da droga anti-retroviral HIV-1 no crescimento de hifas de C. albicans monitoradas pelo sistema "Bio-Cell Tracer"

Directory of Open Access Journals (Sweden)

Nadja Rodrigues de Melo

2006-09-01

Full Text Available Declining incidence of oropharyngeal candidosis and opportunistic infections over recent years can be attributed to the use of highly active anti-retroviral therapy (HAART. Infection with C. albicans generally involves adherence and colonization of superficial tissues. During this process, budding yeasts are able to transform to hyphae and penetrate into the deep tissue. Using the biocell tracer system, C. albicans hyphal growth was dynamically observed at the cellular level. Ritonavir was effective in the inhibition of hyphal growth with growth rate of 0.8 mum/min. This study showed the in vitro effect of HIV anti-retroviral drug on the growth rate of the C. albicans hyphae.O declínio na incidência de candidose orofaríngea e infecções oportunistas associadas a infecção pelo HIV tem sido atribuído a introdução da terapia antiretroviral combinada (HAART. Infecção por C. albicans envolve aderência e colonização da mucosa superficial. Durante este processo leveduras são capazes de transformar-se na forma de hifas e penetrar nos tecidos mais profundos. Usando o sistema "Bio-Cell Tracer", o crescimento de hifas de C. albicans foi observado dinamicamente a nível celular. Ritonavir, inibidor de protease do HIV, foi efetivo na inibição do crescimento de hifas com media de 0.8 mim/min.O presente estudo demonstrou o efeito in vitro de um agente anti-retroviral HIV sobre o crescimento de hifas de C. albicans.

Spectrum of imaging appearances of intracranial cryptococcal infection in HIV/AIDS patients in the anti-retroviral therapy era

International Nuclear Information System (INIS)

Offiah, Curtis E.; Naseer, Aisha

2016-01-01

Cryptococcus neoformans infection is the most common fungal infection of the central nervous system (CNS) in advanced human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS) patients, but remains a relatively uncommon CNS infection in both the immunocompromised and immunocompetent patient population, rendering it a somewhat elusive and frequently overlooked diagnosis. The morbidity and mortality associated with CNS cryptococcal infection can be significantly reduced by early recognition of the imaging appearances by the radiologist in order to focus and expedite clinical management and treatment. The emergence and evolution of anti-retroviral therapy have also impacted significantly on the imaging appearances, morbidity, and mortality of this neuro-infection. The constellation of varied imaging appearances associated with cryptococcal CNS infection in the HIV and AIDS population in the era of highly active anti-retroviral therapy (HAART) will be presented in this review.

Involvement of human endogenous retroviral syncytin-1 in human osteoclast fusion

DEFF Research Database (Denmark)

Søe, Kent; Andersen, Thomas Lykke; Hobolt-Pedersen, Anne-Sofie

2011-01-01

fusion of the lipid bilayers of their cell membranes are still unknown. Syncytin-1 is a protein encoded by a human endogenous retroviral gene which was stably integrated into the human ancestor genome more than 24 million years ago. Upon activation, syncytin-1 is able to destabilize the lipid bilayer....... This was documented through Q-PCR, Western blot and immunofluorescence analyses. These in vitro findings were confirmed by immunohistochemical stainings in human iliac crest biopsies. A syncytin-1 inhibitory peptide reduced the number of nuclei per osteoclast by 30%, as well as TRACP activity. From a mechanistic...

Mechanisms and Factors that Influence High Frequency Retroviral Recombination

Science.gov (United States)

Delviks-Frankenberry, Krista; Galli, Andrea; Nikolaitchik, Olga; Mens, Helene; Pathak, Vinay K.; Hu, Wei-Shau

2011-01-01

With constantly changing environmental selection pressures, retroviruses rely upon recombination to reassort polymorphisms in their genomes and increase genetic diversity, which improves the chances for the survival of their population. Recombination occurs during DNA synthesis, whereby reverse transcriptase undergoes template switching events between the two copackaged RNAs, resulting in a viral recombinant with portions of the genetic information from each parental RNA. This review summarizes our current understanding of the factors and mechanisms influencing retroviral recombination, fidelity of the recombination process, and evaluates the subsequent viral diversity and fitness of the progeny recombinant. Specifically, the high mutation rates and high recombination frequencies of HIV-1 will be analyzed for their roles in influencing HIV-1 global diversity, as well as HIV-1 diagnosis, drug treatment, and vaccine development. PMID:21994801

Evolution of the retroviral restriction gene Fv1: inhibition of non-MLV retroviruses.

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Melvyn W Yap

2014-03-01

Full Text Available Fv1 is the prototypic restriction factor that protects against infection by the murine leukemia virus (MLV. It was first identified in cells that were derived from laboratory mice and was found to be homologous to the gag gene of an endogenous retrovirus (ERV. To understand the evolution of the host restriction gene from its retroviral origins, Fv1s from wild mice were isolated and characterized. Most of these possess intact open reading frames but not all restricted N-, B-, NR-or NB-tropic MLVs, suggesting that other viruses could have played a role in the selection of the gene. The Fv1s from Mus spretus and Mus caroli were found to restrict equine infectious anemia virus (EIAV and feline foamy virus (FFV respectively, indicating that Fv1 could have a broader target range than previously thought, including activity against lentiviruses and spumaviruses. Analyses of the Fv1 sequences revealed a number of residues in the C-terminal region that had evolved under positive selection. Four of these selected residues were found to be involved in the novel restriction by mapping studies. These results strengthen the similarities between the two capsid binding restriction factors, Fv1 and TRIM5α, which support the hypothesis that Fv1 defended mice against waves of retroviral infection possibly including non-MLVs as well as MLVs.

Reprogramming Methods Do Not Affect Gene Expression Profile of Human Induced Pluripotent Stem Cells.

Science.gov (United States)

Trevisan, Marta; Desole, Giovanna; Costanzi, Giulia; Lavezzo, Enrico; Palù, Giorgio; Barzon, Luisa

2017-01-20

Induced pluripotent stem cells (iPSCs) are pluripotent cells derived from adult somatic cells. After the pioneering work by Yamanaka, who first generated iPSCs by retroviral transduction of four reprogramming factors, several alternative methods to obtain iPSCs have been developed in order to increase the yield and safety of the process. However, the question remains open on whether the different reprogramming methods can influence the pluripotency features of the derived lines. In this study, three different strategies, based on retroviral vectors, episomal vectors, and Sendai virus vectors, were applied to derive iPSCs from human fibroblasts. The reprogramming efficiency of the methods based on episomal and Sendai virus vectors was higher than that of the retroviral vector-based approach. All human iPSC clones derived with the different methods showed the typical features of pluripotent stem cells, including the expression of alkaline phosphatase and stemness maker genes, and could give rise to the three germ layer derivatives upon embryoid bodies assay. Microarray analysis confirmed the presence of typical stem cell gene expression profiles in all iPSC clones and did not identify any significant difference among reprogramming methods. In conclusion, the use of different reprogramming methods is equivalent and does not affect gene expression profile of the derived human iPSCs.

Mutation of C/EBPalpha predisposes to the development of myeloid leukemia in a retroviral insertional mutagenesis screen

DEFF Research Database (Denmark)

Hasemann, Marie S; Damgaard, Inge; Schuster, Mikkel B

2008-01-01

and incomplete penetrance, suggesting that accumulation of secondary mutations is necessary for disease progression. Here, we use SRS19-6-driven retroviral insertional mutagenesis to compare the phenotypes of leukemias arising in Cebpa(+/+), Cebpa(+/BRM2), and Cebpa(BRM2/BRM2) mice, with respect to disease type...

An introduction to vectors, vector operators and vector analysis

CERN Document Server

Joag, Pramod S

2016-01-01

Ideal for undergraduate and graduate students of science and engineering, this book covers fundamental concepts of vectors and their applications in a single volume. The first unit deals with basic formulation, both conceptual and theoretical. It discusses applications of algebraic operations, Levi-Civita notation, and curvilinear coordinate systems like spherical polar and parabolic systems and structures, and analytical geometry of curves and surfaces. The second unit delves into the algebra of operators and their types and also explains the equivalence between the algebra of vector operators and the algebra of matrices. Formulation of eigen vectors and eigen values of a linear vector operator are elaborated using vector algebra. The third unit deals with vector analysis, discussing vector valued functions of a scalar variable and functions of vector argument (both scalar valued and vector valued), thus covering both the scalar vector fields and vector integration.

RetroTector online, a rational tool for analysis of retroviral elements in small and medium size vertebrate genomic sequences.

Science.gov (United States)

Sperber, Göran; Lövgren, Anders; Eriksson, Nils-Einar; Benachenhou, Farid; Blomberg, Jonas

2009-06-16

The rapid accumulation of genomic information in databases necessitates rapid and specific algorithms for extracting biologically meaningful information. More or less complete retroviral sequences, also called proviral or endogenous retroviral sequences; ERVs, constitutes at least 5% of vertebrate genomes. After infecting the host, these retroviruses have integrated in germ line cells, and have then been carried in genomes for at least several 100 million years. A better understanding of structure and function of these sequences can have profound biological and medical consequences. RetroTector (ReTe) is a platform-independent Java program for identification and characterization of proviral sequences in vertebrate genomes. The full ReTe requires a local installation with a MySQL database. Although not overly complicated, the installation may take some time. A "light" version of ReTe, (RetroTector online; ROL) which does not require specific installation procedures is provided, via the World Wide Web. ROL http://www.fysiologi.neuro.uu.se/jbgs/ was implemented under the Batchelor web interface (A Lövgren et al). It allows both GenBank accession number, file and FASTA cut-and-paste admission of sequences (5 to 10,000 kilobases). Up to ten submissions can be done simultaneously, allowing batch analysis of retroviral sequences found in the submitted sequence is graphically presented, exportable in standard formats. With the current server, a complete analysis of a 1 Megabase sequence is complete in 10 minutes. It is possible to mask nonretroviral repetitive sequences in the submitted sequence, using host genome specific "brooms", which increase specificity. Proviral sequences can be hard to recognize

Electronic medication monitoring-informed counseling to improve adherence to combination anti-retroviral therapy and virologic treatment outcomes: a meta-analysis

NARCIS (Netherlands)

Langebeek, Nienke; Nieuwkerk, Pythia

2015-01-01

Adherence to combination anti-retroviral therapy for HIV infection is a primary determinant of treatment success, but is often suboptimal. Previous studies have suggested that electronic medication monitoring-informed counseling is among the most effective adherence intervention components. Our

Reprogramming Methods Do Not Affect Gene Expression Profile of Human Induced Pluripotent Stem Cells

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Marta Trevisan

2017-01-01

Full Text Available Induced pluripotent stem cells (iPSCs are pluripotent cells derived from adult somatic cells. After the pioneering work by Yamanaka, who first generated iPSCs by retroviral transduction of four reprogramming factors, several alternative methods to obtain iPSCs have been developed in order to increase the yield and safety of the process. However, the question remains open on whether the different reprogramming methods can influence the pluripotency features of the derived lines. In this study, three different strategies, based on retroviral vectors, episomal vectors, and Sendai virus vectors, were applied to derive iPSCs from human fibroblasts. The reprogramming efficiency of the methods based on episomal and Sendai virus vectors was higher than that of the retroviral vector-based approach. All human iPSC clones derived with the different methods showed the typical features of pluripotent stem cells, including the expression of alkaline phosphatase and stemness maker genes, and could give rise to the three germ layer derivatives upon embryoid bodies assay. Microarray analysis confirmed the presence of typical stem cell gene expression profiles in all iPSC clones and did not identify any significant difference among reprogramming methods. In conclusion, the use of different reprogramming methods is equivalent and does not affect gene expression profile of the derived human iPSCs.

RetroTector online, a rational tool for analysis of retroviral elements in small and medium size vertebrate genomic sequences

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Benachenhou Farid

2009-06-01

Full Text Available Abstract Background The rapid accumulation of genomic information in databases necessitates rapid and specific algorithms for extracting biologically meaningful information. More or less complete retroviral sequences, also called proviral or endogenous retroviral sequences; ERVs, constitutes at least 5% of vertebrate genomes. After infecting the host, these retroviruses have integrated in germ line cells, and have then been carried in genomes for at least several 100 million years. A better understanding of structure and function of these sequences can have profound biological and medical consequences. Methods RetroTector© (ReTe is a platform-independent Java program for identification and characterization of proviral sequences in vertebrate genomes. The full ReTe requires a local installation with a MySQL database. Although not overly complicated, the installation may take some time. A "light" version of ReTe, (RetroTector online; ROL which does not require specific installation procedures is provided, via the World Wide Web. Results ROL http://www.fysiologi.neuro.uu.se/jbgs/ was implemented under the Batchelor web interface (A Lövgren et al. It allows both GenBank accession number, file and FASTA cut-and-paste admission of sequences (5 to 10 000 kilobases. Up to ten submissions can be done simultaneously, allowing batch analysis of Discussion Proviral sequences can be hard to recognize, especially if the integration occurred many million years ago. Precise delineation of LTR, gag, pro, pol and env can be difficult, requiring manual work. ROL is a way of simplifying these tasks. Conclusion ROL provides 1. annotation and presentation of known retroviral sequences, 2. detection of proviral chains in unknown genomic sequences, with up to 100 Mbase per submission.

Long-term expression of human adenosine deaminase in mice transplanted with retrovirus-infected hematopoietic stem cells

International Nuclear Information System (INIS)

Lim, B.; Apperley, J.F.; Orkin, S.H.; Williams, D.A.

1989-01-01

Long-term stable expression of foreign genetic sequences transferred into hematopoietic stem cells by using retroviral vectors constitutes a relevant model for somatic gene therapy. Such stability of expression may depend on vector design, including the presence or absence of specific sequences within the vector, in combination with the nature and efficiency of infection of the hematopoietic target cells. The authors have previously reported successful transfer of human DNA encoding adenosine deaminase (ADA) into CFU-S (colony-forming unit-spleen) stem cells using simplified recombinant retroviral vectors. Human ADA was expressed in CFU-S-derived spleen colonies at levels near to endogenous enzyme. However, because of the lack of an efficient dominant selectable marker and low recombinant viral titers, stability of long-term expression of human ADA was not examined. They report here the development of an efficient method of infection of hematopoietic stem cells (HSC) without reliance on in vitro selection. Peripheral blood samples of 100% of mice transplanted with HSC infected by this protocol exhibit expression of human ADA 30 days after transplantation. Some mice (6 of 13) continue to express human ADA in all lineages after complete hematopoietic reconstitution (4 months). The use of recombinant retroviral vectors that efficiently transfer human ADA cDNA into HSC leading to stable expression of functional ADA in reconstituted mice, provides an experimental framework for future development of approaches to somatic gene therapy

Efficient transduction of neurons using Ross River glycoprotein-pseudotyped lentiviral vectors

DEFF Research Database (Denmark)

Jakobsson, J; Nielsen, T Tolstrup; Staflin, K

2006-01-01

, including the possibility to establish stable producer cell lines. After injection of RRV-LV expressing green fluorescent protein into different structures in the rat brain we found efficient transduction of both neurons and glial cells. By using two cell-type-specific promoters, neuron-specific enolase...

Highly efficient transduction of human plasmacytoid dendritic cells without phenotypic and functional maturation

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Plumas Joel

2009-01-01

Full Text Available Abstract Background Gene modified dendritic cells (DC are able to modulate DC functions and induce therapeutic immunity or tolerance in an antigen-specific manner. Among the different DC subsets, plasmacytoid DC (pDC are well known for their ability to recognize and respond to a variety of viruses by secreting high levels of type I interferon. Methods We analyzed here, the transduction efficiency of a pDC cell line, GEN2.2, and of pDC derived from CD34+ progenitors, using lentiviral vectors (LV pseudotyped with different envelope glycoproteins such as the vesicular stomatitis virus envelope (VSVG, the gibbon ape leukaemia virus envelope (GaLV or the feline endogenous virus envelope (RD114. At the same time, we evaluated transgene expression (E-GFP reporter gene under the control of different promoters. Results We found that efficient gene transfer into pDC can be achieved with VSVG-pseudotyped lentiviral vectors (LV under the control of phoshoglycerate kinase (PGK and elongation factor-1 (EF1α promoters (28% to 90% of E-GFP+ cells, respectively in the absence of phenotypic and functional maturation. Surprisingly, promoters (desmin or synthetic C5–12 described as muscle-specific and which drive gene expression in single strand AAV vectors in gene therapy protocols were very highly active in pDC using VSVG-LV. Conclusion Taken together, our results indicate that LV vectors can serve to design pDC-based vaccines in humans, and they are also useful in vitro to evaluate the immunogenicity of the vector preparations, and the specificity and safety of given promoters used in gene therapy protocols.

The Host RNAs in Retroviral Particles

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Alice Telesnitsky

2016-08-01

Full Text Available As they assemble, retroviruses encapsidate both their genomic RNAs and several types of host RNA. Whereas limited amounts of messenger RNA (mRNA are detectable within virion populations, the predominant classes of encapsidated host RNAs do not encode proteins, but instead include endogenous retroelements and several classes of non-coding RNA (ncRNA, some of which are packaged in significant molar excess to the viral genome. Surprisingly, although the most abundant host RNAs in retroviruses are also abundant in cells, unusual forms of these RNAs are packaged preferentially, suggesting that these RNAs are recruited early in their biogenesis: before associating with their cognate protein partners, and/or from transient or rare RNA populations. These RNAs’ packaging determinants differ from the viral genome’s, and several of the abundantly packaged host ncRNAs serve cells as the scaffolds of ribonucleoprotein particles. Because virion assembly is equally efficient whether or not genomic RNA is available, yet RNA appears critical to the structural integrity of retroviral particles, it seems possible that the selectively encapsidated host ncRNAs might play roles in assembly. Indeed, some host ncRNAs appear to act during replication, as some transfer RNA (tRNA species may contribute to nuclear import of human immunodeficiency virus 1 (HIV-1 reverse transcription complexes, and other tRNA interactions with the viral Gag protein aid correct trafficking to plasma membrane assembly sites. However, despite high conservation of packaging for certain host RNAs, replication roles for most of these selectively encapsidated RNAs—if any—have remained elusive.

Replacement of the murine leukemia virus (MLV) envelope gene with a truncated HIV envelope gene in MLV generates a virus with impaired replication capacity

International Nuclear Information System (INIS)

Nack, Ursula; Schnierle, Barbara S.

2003-01-01

Murine leukemia virus (MLV) capsid particles can be efficiently pseudotyped with a variant of the HIV-1 envelope protein (Env) containing the surface glycoprotein gp120-SU and a carboxyl-terminally truncated transmembrane (TM) protein, with only seven cytoplasmic amino acids. MLV/HIV pseudotyped vector particles acquire the natural host tropism of HIV-1 and their entry is dependent on the presence of CD4 and an appropriate co-receptor on the surface of the target cell. We describe here the construction of chimeric MLV/HIV proviruses containing the truncated HIV envelope gene. The MLV/HIV provirus was generated by direct replacement of the MLV envelope gene with HIV Env coding sequences either with or without the additional inclusion of the woodchuck hepatitis virus posttranscriptional regulatory element (WPRE). Chimeric MLV/HIV particles could be generated from transfected 293T cells and were able to infect CD4/CXCR4-positive target cells. However, the second round of infection of target cells was severely impaired, despite the fact that the WPRE element enhanced the amount of viral mRNA detected. Viral particles released from infected cells showed reduced HIV Env incorporation, indicating that additional factors required for efficient replication of MLV/HIV pseudotyped viruses are missing

“Marker of Self” CD47 on lentiviral vectors decreases macrophage-mediated clearance and increases delivery to SIRPA-expressing lung carcinoma tumors

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Nisha G Sosale

2016-01-01

Full Text Available Lentiviruses infect many cell types and are now widely used for gene delivery in vitro, but in vivo uptake of these foreign vectors by macrophages is a limitation. Lentivectors are produced here from packaging cells that overexpress “Marker of Self” CD47, which inhibits macrophage uptake of cells when prophagocytic factors are also displayed. Single particle analyses show “hCD47-Lenti” display properly oriented human-CD47 for interactions with the macrophage's inhibitory receptor SIRPA. Macrophages derived from human and NOD/SCID/Il2rg−/− (NSG mice show a SIRPA-dependent decrease in transduction, i.e., transgene expression, by hCD47-Lenti compared to control Lenti. Consistent with known “Self” signaling pathways, macrophage transduction by control Lenti is decreased by drug inhibition of Myosin-II to the same levels as hCD47-Lenti. In contrast, human lung carcinoma cells express SIRPA and use it to enhance transduction by hCD47-Lenti- as illustrated by more efficient gene deletion using CRISPR/Cas9. Intravenous injection of hCD47-Lenti into NSG mice shows hCD47 prolongs circulation, unless a blocking anti-SIRPA is preinjected. In vivo transduction of spleen and liver macrophages also decreases for hCD47-Lenti while transduction of lung carcinoma xenografts increases. hCD47 could be useful when macrophage uptake is limiting on other viral vectors that are emerging in cancer treatments (e.g., Measles glycoprotein-pseudotyped lentivectors and also in targeting various SIRPA-expressing tumors such as glioblastomas.

A small and efficient dimerization/packaging signal of rat VL30 RNA and its use in murine leukemia virus-VL30-derived vectors for gene transfer.

Science.gov (United States)

Torrent, C; Gabus, C; Darlix, J L

1994-02-01

Retroviral genomes consist of two identical RNA molecules associated at their 5' ends by the dimer linkage structure located in the packaging element (Psi or E) necessary for RNA dimerization in vitro and packaging in vivo. In murine leukemia virus (MLV)-derived vectors designed for gene transfer, the Psi + sequence of 600 nucleotides directs the packaging of recombinant RNAs into MLV virions produced by helper cells. By using in vitro RNA dimerization as a screening system, a sequence of rat VL30 RNA located next to the 5' end of the Harvey mouse sarcoma virus genome and as small as 67 nucleotides was found to form stable dimeric RNA. In addition, a purine-rich sequence located at the 5' end of this VL30 RNA seems to be critical for RNA dimerization. When this VL30 element was extended by 107 nucleotides at its 3' end and inserted into an MLV-derived vector lacking MLV Psi +, it directed the efficient encapsidation of recombinant RNAs into MLV virions. Because this VL30 packaging signal is smaller and more efficient in packaging recombinant RNAs than the MLV Psi + and does not contain gag or glyco-gag coding sequences, its use in MLV-derived vectors should render even more unlikely recombinations which could generate replication-competent viruses. Therefore, utilization of the rat VL30 packaging sequence should improve the biological safety of MLV vectors for human gene transfer.

PR01 Molecular Pathogenesis of Rickettsioses and Development of Anti-Rickettsial Treatment by Combinatorial Peptide-Based Libraries

National Research Council Canada - National Science Library

Walker, David H

2006-01-01

The purpose of this study is to utilize adaptein libraries coded within pantropic retroviral vectors that confer protection against rickettsial pathogens and to study the molecular pathogenesis of rickettsioses...

Efficient generation of integration-free human induced pluripotent stem cells from keratinocytes by simple transfection of episomal vectors.

Science.gov (United States)

Piao, Yulan; Hung, Sandy Shen-Chi; Lim, Shiang Y; Wong, Raymond Ching-Bong; Ko, Minoru S H

2014-07-01

Keratinocytes represent an easily accessible cell source for derivation of human induced pluripotent stem (hiPS) cells, reportedly achieving higher reprogramming efficiency than fibroblasts. However, most studies utilized a retroviral or lentiviral method for reprogramming of keratinocytes, which introduces undesirable transgene integrations into the host genome. Moreover, current protocols of generating integration-free hiPS cells from keratinocytes are mostly inefficient. In this paper, we describe a more efficient, simple-to-use, and cost-effective method for generating integration-free hiPS cells from keratinocytes. Our improved method using lipid-mediated transfection achieved a reprogramming efficiency of ∼0.14% on average. Keratinocyte-derived hiPS cells showed no integration of episomal vectors, expressed stem cell-specific markers and possessed potentials to differentiate into all three germ layers by in vitro embryoid body formation as well as in vivo teratoma formation. To our knowledge, this represents the most efficient method to generate integration-free hiPS cells from keratinocytes. ©AlphaMed Press.

Analysis of bone marrow stromal cell transferred bacterial {beta}-galactosidase gene by PIXE

Energy Technology Data Exchange (ETDEWEB)

Kumakawa, Toshiro [Tokyo Metropolitan Geriatric Hospital, Tokyo (Japan). Dept. of Blood Transfusion and Hematology; Hibino, Hitoshi; Tani, Kenzaburo; Asano, Shigetaka; Futatugawa, Shouji; Sera, Kouichiro

1997-12-31

PIXE, Particle Induced X-ray Emission, is a powerful, multi-elemental analysis method which has many distinguishing features and has been used in varies research fields. Recently the method of applying baby cyclotrons for nuclear medicine to PIXE has been developed. This enables us to study biomedical phenomena from the physical point of view. Mouse bone marrow stromal cells were transferred bacterial {beta}-galactosidase gene (LacZ gene) by murine retroviral vectors. Analysis of the bone marrow stromal cells with the LacZ gene by PIXE revealed remarkable changes of intracellular trace elements compared with the normal control cells. These results indicate that gene transfer by retroviral vectors may bring about a dynamic change of intracellular circumstances of the target cell. (author)

Retroviral DNA Integration Directed by HIV Integration Protein in Vitro

Science.gov (United States)

Bushman, Frederic D.; Fujiwara, Tamio; Craigie, Robert

1990-09-01

Efficient retroviral growth requires integration of a DNA copy of the viral RNA genome into a chromosome of the host. As a first step in analyzing the mechanism of integration of human immunodeficiency virus (HIV) DNA, a cell-free system was established that models the integration reaction. The in vitro system depends on the HIV integration (IN) protein, which was partially purified from insect cells engineered to express IN protein in large quantities. Integration was detected in a biological assay that scores the insertion of a linear DNA containing HIV terminal sequences into a λ DNA target. Some integration products generated in this assay contained five-base pair duplications of the target DNA at the recombination junctions, a characteristic of HIV integration in vivo; the remaining products contained aberrant junctional sequences that may have been produced in a variation of the normal reaction. These results indicate that HIV IN protein is the only viral protein required to insert model HIV DNA sequences into a target DNA in vitro.

Retroviral-mediated gene therapy for the differentiation of primary cells into a mineralizing osteoblastic phenotype.

Science.gov (United States)

Phillips, Jennifer E; García, Andrés J

2008-01-01

Bone tissue engineering has emerged as a promising strategy for the repair of critical-sized skeletal fractures. However, the clinical application of this approach has been limited by the availability of a robust mineralizing cell source. Non-osteogenic cells, such as skin fibroblasts, are an attractive cell-source alternative because they are easy to harvest from autologous donor skin biopsies and display a high capacity for in vitro expansion. We have recently demonstrated that retroviral gene delivery of the osteoblastic transcription factor Runx2/Cbfa1 promotes osteogenic differentiation in primary dermal fibroblasts cultured in monolayer. Notably, sustained expression of Runx2 was not sufficient to promote functional osteogenesis in these cells, and co-treatment with the steroid hormone dexamethasone was required to induce deposition of biologically-equivalent matrix mineralization. On the basis of these results, we then investigated the osteogenic capacity of these genetically engineered fibroblasts when seeded on polymeric scaffolds in vitro and in vivo. These experiments demonstrated that Runx2-expressing fibroblasts seeded on collagen scaffolds produce significant levels of matrix mineralization after 28 days in vivo implantation in a subcutaneous, heterotopic site. Overall, these results offer evidence that transcription factor-based gene therapy may be a powerful strategy for the conversion of a non-osteogenic cellular phenotype into a mineralizing cell source for bone repair applications. This concept may also be applied to control functional differentiation in a broad range of cell types and tissue engineering applications. The chapter below outlines detailed methods for the isolation and ex vivo genetic modification of primary dermal fibroblasts using retroviral-mediated delivery of the Runx2 transgene in both monolayer culture and three-dimensional scaffolds.

O-linked glycosylation of retroviral envelope gene products

Energy Technology Data Exchange (ETDEWEB)

Pinter, A.; Honnen, W.J. (Public Health Research Institute of the City of New York Inc., NY (USA))

1988-03-01

Treatment of ({sup 3}H)glucosamine-labeled Friend mink cell focus-forming virus (FrMCF) gp70 with excess peptide:N-glycanase F (PNGase F) resulted in removal of the expected seven N-linked oligosaccharide chains; however, approximately 10% of the glucosamine label was retained in the resulting 49,000-M{sub r} (49K) product. For ({sup 3}H)mannose-labeled gp70, similar treatment led to removal of all the carbohydrate label from the protein. Prior digestion of the PNGase F-treated gp70 with neuraminidase resulted in an addition size shift, and treatment with O-glycanase led to the removal of almost all of the PNGase F-resistant sugars. These results indicate that gp70 possesses sialic acid-containing O-linked oligosaccharides. Analysis of intracellular env precursors demonstrated that O-linked sugars were present in gPr90{sup env}, the polyprotein intermediate which contains complex sugars, but not in the primary translation product, gPr80{sup env}, and proteolytic digestion studies allowed localization of the O-linked carbohydrates to a 10K region near the center of the gp70 molecule. similar substituents were detected on the gp70s of ecotropic and xenotropic murine leukemia viruses and two subgroups of feline leukemia virus, indicting that O-linked glycosylation is a conserved feature of retroviral env proteins.

O-linked glycosylation of retroviral envelope gene products

International Nuclear Information System (INIS)

Pinter, A.; Honnen, W.J.

1988-01-01

Treatment of [ 3 H]glucosamine-labeled Friend mink cell focus-forming virus (FrMCF) gp70 with excess peptide:N-glycanase F (PNGase F) resulted in removal of the expected seven N-linked oligosaccharide chains; however, approximately 10% of the glucosamine label was retained in the resulting 49,000-M r (49K) product. For [ 3 H]mannose-labeled gp70, similar treatment led to removal of all the carbohydrate label from the protein. Prior digestion of the PNGase F-treated gp70 with neuraminidase resulted in an addition size shift, and treatment with O-glycanase led to the removal of almost all of the PNGase F-resistant sugars. These results indicate that gp70 possesses sialic acid-containing O-linked oligosaccharides. Analysis of intracellular env precursors demonstrated that O-linked sugars were present in gPr90 env , the polyprotein intermediate which contains complex sugars, but not in the primary translation product, gPr80 env , and proteolytic digestion studies allowed localization of the O-linked carbohydrates to a 10K region near the center of the gp70 molecule. similar substituents were detected on the gp70s of ecotropic and xenotropic murine leukemia viruses and two subgroups of feline leukemia virus, indicting that O-linked glycosylation is a conserved feature of retroviral env proteins

Identification of Hematopoietic Stem Cell Engraftment Genes in Gene Therapy Studies.

Science.gov (United States)

Powers, John M; Trobridge, Grant D

2013-09-01

Hematopoietic stem cell (HSC) therapy using replication-incompetent retroviral vectors is a promising approach to provide life-long correction for genetic defects. HSC gene therapy clinical studies have resulted in functional cures for several diseases, but in some studies clonal expansion or leukemia has occurred. This is due to the dyregulation of endogenous host gene expression from vector provirus insertional mutagenesis. Insertional mutagenesis screens using replicating retroviruses have been used extensively to identify genes that influence oncogenesis. However, retroviral mutagenesis screens can also be used to determine the role of genes in biological processes such as stem cell engraftment. The aim of this review is to describe the potential for vector insertion site data from gene therapy studies to provide novel insights into mechanisms of HSC engraftment. In HSC gene therapy studies dysregulation of host genes by replication-incompetent vector proviruses may lead to enrichment of repopulating clones with vector integrants near genes that influence engraftment. Thus, data from HSC gene therapy studies can be used to identify novel candidate engraftment genes. As HSC gene therapy use continues to expand, the vector insertion site data collected will be of great interest to help identify novel engraftment genes and may ultimately lead to new therapies to improve engraftment.

Apoptosis Gene Hunting Using Retroviral Expression Cloning: Identification of Vacuolar ATPase Subunit E

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Claire L. Anderson

2003-01-01

Full Text Available Over the past 10-15 years there has been an explosion of interest in apoptosis. The delayed realisation that cell death is an essential part of life for any multicellular organism has meant that, despite the recent and rapid developments of the last decade, the precise biochemical pathways involved in apoptosis remain incomplete and potentially novel genes may, as yet, remain undiscovered. The hunt is therefore on to bridge the remaining gaps in our knowledge. Our contribution to this research effort utilises a functional cloning approach to isolate important regulatory genes involved in apoptosis. This mini-review focuses on the use and advantages of a retroviral expression cloning strategy and describes the isolation and identification of one such potential apoptosis regulatory gene, namely that encoding vacuolar ATPase subunit E.

Endogenous retroviruses mobilized during friend murine leukemia virus infection.

Science.gov (United States)

Boi, Stefano; Rosenke, Kyle; Hansen, Ethan; Hendrick, Duncan; Malik, Frank; Evans, Leonard H

2016-12-01

We have demonstrated in a mouse model that infection with a retrovirus can lead not only to the generation of recombinants between exogenous and endogenous gammaretrovirus, but also to the mobilization of endogenous proviruses by pseudotyping entire polytropic proviral transcripts and facilitating their infectious spread to new cells. However, the frequency of this occurrence, the kinetics, and the identity of mobilized endogenous proviruses was unclear. Here we find that these mobilized transcripts are detected after only one day of infection. They predominate over recombinant polytropic viruses early in infection, persist throughout the course of disease and are comprised of multiple different polytropic proviruses. Other endogenous retroviral elements such as intracisternal A particles (IAPs) were not detected. The integration of the endogenous transcripts into new cells could result in loss of transcriptional control and elevated expression which may facilitate pathogenesis, perhaps by contributing to the generation of polytropic recombinant viruses. Published by Elsevier Inc.

Lineage analysis of the late otocyst stage mouse inner ear by transuterine microinjection of a retroviral vector encoding alkaline phosphatase and an oligonucleotide library.

Directory of Open Access Journals (Sweden)

Han Jiang

Full Text Available The mammalian inner ear subserves the special senses of hearing and balance. The auditory and vestibular sensory epithelia consist of mechanically sensitive hair cells and associated supporting cells. Hearing loss and balance dysfunction are most frequently caused by compromise of hair cells and/or their innervating neurons. The development of gene- and cell-based therapeutics will benefit from a thorough understanding of the molecular basis of patterning and cell fate specification in the mammalian inner ear. This includes analyses of cell lineages and cell dispersals across anatomical boundaries (such as sensory versus nonsensory territories. The goal of this study was to conduct retroviral lineage analysis of the embryonic day 11.5(E11.5 mouse otic vesicle. A replication-defective retrovirus encoding human placental alkaline phosphatase (PLAP and a variable 24-bp oligonucleotide tag was microinjected into the E11.5 mouse otocyst. PLAP-positive cells were microdissected from cryostat sections of the postnatal inner ear and subjected to nested PCR. PLAP-positive cells sharing the same sequence tag were assumed to have arisen from a common progenitor and are clonally related. Thirty five multicellular clones consisting of an average of 3.4 cells per clone were identified in the auditory and vestibular sensory epithelia, ganglia, spiral limbus, and stria vascularis. Vestibular hair cells in the posterior crista were related to one another, their supporting cells, and nonsensory epithelial cells lining the ampulla. In the organ of Corti, outer hair cells were related to a supporting cell type and were tightly clustered. By contrast, spiral ganglion neurons, interdental cells, and Claudius' cells were related to cells of the same type and could be dispersed over hundreds of microns. These data contribute new information about the developmental potential of mammalian otic precursors in vivo.

Emerging Vector-Borne Diseases - Incidence through Vectors.

Science.gov (United States)

Savić, Sara; Vidić, Branka; Grgić, Zivoslav; Potkonjak, Aleksandar; Spasojevic, Ljubica

2014-01-01

Vector-borne diseases use to be a major public health concern only in tropical and subtropical areas, but today they are an emerging threat for the continental and developed countries also. Nowadays, in intercontinental countries, there is a struggle with emerging diseases, which have found their way to appear through vectors. Vector-borne zoonotic diseases occur when vectors, animal hosts, climate conditions, pathogens, and susceptible human population exist at the same time, at the same place. Global climate change is predicted to lead to an increase in vector-borne infectious diseases and disease outbreaks. It could affect the range and population of pathogens, host and vectors, transmission season, etc. Reliable surveillance for diseases that are most likely to emerge is required. Canine vector-borne diseases represent a complex group of diseases including anaplasmosis, babesiosis, bartonellosis, borreliosis, dirofilariosis, ehrlichiosis, and leishmaniosis. Some of these diseases cause serious clinical symptoms in dogs and some of them have a zoonotic potential with an effect to public health. It is expected from veterinarians in coordination with medical doctors to play a fundamental role at primarily prevention and then treatment of vector-borne diseases in dogs. The One Health concept has to be integrated into the struggle against emerging diseases. During a 4-year period, from 2009 to 2013, a total number of 551 dog samples were analyzed for vector-borne diseases (borreliosis, babesiosis, ehrlichiosis, anaplasmosis, dirofilariosis, and leishmaniasis) in routine laboratory work. The analysis was done by serological tests - ELISA for borreliosis, dirofilariosis, and leishmaniasis, modified Knott test for dirofilariosis, and blood smear for babesiosis, ehrlichiosis, and anaplasmosis. This number of samples represented 75% of total number of samples that were sent for analysis for different diseases in dogs. Annually, on average more then half of the samples

Cloning of Novel Oncogenes Involved in Human Breast Cancer

National Research Council Canada - National Science Library

Clark, Geoffrey

1998-01-01

.... In order to identify genes which may play a role in breast cancer we have begun a process of manufacturing cDNA expression libraries derived from human breast tumor cell lines in retroviral vectors...

Vector analysis

CERN Document Server

Newell, Homer E

2006-01-01

When employed with skill and understanding, vector analysis can be a practical and powerful tool. This text develops the algebra and calculus of vectors in a manner useful to physicists and engineers. Numerous exercises (with answers) not only provide practice in manipulation but also help establish students' physical and geometric intuition in regard to vectors and vector concepts.Part I, the basic portion of the text, consists of a thorough treatment of vector algebra and the vector calculus. Part II presents the illustrative matter, demonstrating applications to kinematics, mechanics, and e

The RNA binding G-patch domain in retroviral protease is important for infectivity and D-type morphogenesis of Mason-Pfizer monkey virus

Czech Academy of Sciences Publication Activity Database

Bauerová, Helena; Štokrová, Jitka; Stříšovský, Kvido; Hunter, E.; Ruml, Tomáš; Pichová, Iva

2005-01-01

Roč. 280, č. 51 (2005), s. 42106-42112 ISSN 0021-9258 R&D Projects: GA MŠk(CZ) 1M0508; GA MŠk(CZ) 1M0520 Institutional research plan: CEZ:AV0Z40550506; CEZ:AV0Z50520514 Keywords : retroviral protease * RNA binding domain * M-PMV * infectivity * assembly Subject RIV: CE - Biochemistry Impact factor: 5.854, year: 2005

Vector-Tensor and Vector-Vector Decay Amplitude Analysis of B0→φK*0

International Nuclear Information System (INIS)

Aubert, B.; Bona, M.; Boutigny, D.; Couderc, F.; Karyotakis, Y.; Lees, J. P.; Poireau, V.; Tisserand, V.; Zghiche, A.; Grauges, E.; Palano, A.; Chen, J. C.; Qi, N. D.; Rong, G.; Wang, P.; Zhu, Y. S.; Eigen, G.; Ofte, I.; Stugu, B.; Abrams, G. S.

2007-01-01

We perform an amplitude analysis of the decays B 0 →φK 2 * (1430) 0 , φK * (892) 0 , and φ(Kπ) S-wave 0 with a sample of about 384x10 6 BB pairs recorded with the BABAR detector. The fractions of longitudinal polarization f L of the vector-tensor and vector-vector decay modes are measured to be 0.853 -0.069 +0.061 ±0.036 and 0.506±0.040±0.015, respectively. Overall, twelve parameters are measured for the vector-vector decay and seven parameters for the vector-tensor decay, including the branching fractions and parameters sensitive to CP violation

About vectors

CERN Document Server

Hoffmann, Banesh

1975-01-01

From his unusual beginning in ""Defining a vector"" to his final comments on ""What then is a vector?"" author Banesh Hoffmann has written a book that is provocative and unconventional. In his emphasis on the unresolved issue of defining a vector, Hoffmann mixes pure and applied mathematics without using calculus. The result is a treatment that can serve as a supplement and corrective to textbooks, as well as collateral reading in all courses that deal with vectors. Major topics include vectors and the parallelogram law; algebraic notation and basic ideas; vector algebra; scalars and scalar p

Retroviral infection of non-dividing cells: Old and new perspectives

International Nuclear Information System (INIS)

Yamashita, Masahiro; Emerman, Michael

2006-01-01

The dependence of retroviral replication on cell proliferation was described as early as 1958, although different classes of retroviruses are able to infect non-dividing cells with different efficiencies. For example, the human immunodeficiency virus (HIV) and other lentiviruses infect most non-dividing cells nearly as well as dividing cells, while the gammaretroviruses such as the murine leukemia virus (MLV) cannot infect non-dividing cells, and other retroviruses have intermediate phenotypes. One exception to the ability of HIV to infect non-dividing cells involves resting CD4+ T cells in vitro where there are multiple restrictions. However, recent data show that there is massive infection of non-activated CD4+ T cell during acute infection which suggests that the situation is different in vivo. Finally, much work trying to explain the difference between HIV and MLV in non-dividing cells has focused on describing the ability of HIV to enter the nucleus during interphase. However, we suggest that events in the viral lifecycle other than nuclear import may be more important in determining the ability of a given retrovirus to infect non-dividing cells

Vectors

DEFF Research Database (Denmark)

Boeriis, Morten; van Leeuwen, Theo

2017-01-01

should be taken into account in discussing ‘reactions’, which Kress and van Leeuwen link only to eyeline vectors. Finally, the question can be raised as to whether actions are always realized by vectors. Drawing on a re-reading of Rudolf Arnheim’s account of vectors, these issues are outlined......This article revisits the concept of vectors, which, in Kress and van Leeuwen’s Reading Images (2006), plays a crucial role in distinguishing between ‘narrative’, action-oriented processes and ‘conceptual’, state-oriented processes. The use of this concept in image analysis has usually focused...

Vector regression introduced

Directory of Open Access Journals (Sweden)

Mok Tik

2014-06-01

Full Text Available This study formulates regression of vector data that will enable statistical analysis of various geodetic phenomena such as, polar motion, ocean currents, typhoon/hurricane tracking, crustal deformations, and precursory earthquake signals. The observed vector variable of an event (dependent vector variable is expressed as a function of a number of hypothesized phenomena realized also as vector variables (independent vector variables and/or scalar variables that are likely to impact the dependent vector variable. The proposed representation has the unique property of solving the coefficients of independent vector variables (explanatory variables also as vectors, hence it supersedes multivariate multiple regression models, in which the unknown coefficients are scalar quantities. For the solution, complex numbers are used to rep- resent vector information, and the method of least squares is deployed to estimate the vector model parameters after transforming the complex vector regression model into a real vector regression model through isomorphism. Various operational statistics for testing the predictive significance of the estimated vector parameter coefficients are also derived. A simple numerical example demonstrates the use of the proposed vector regression analysis in modeling typhoon paths.

Neutralizing Activity of Broadly Neutralizing Anti-HIV-1 Antibodies against Clade B Clinical Isolates Produced in Peripheral Blood Mononuclear Cells.

Science.gov (United States)

Cohen, Yehuda Z; Lorenzi, Julio C C; Seaman, Michael S; Nogueira, Lilian; Schoofs, Till; Krassnig, Lisa; Butler, Allison; Millard, Katrina; Fitzsimons, Tomas; Daniell, Xiaoju; Dizon, Juan P; Shimeliovich, Irina; Montefiori, David C; Caskey, Marina; Nussenzweig, Michel C

2018-03-01

HIV-1 epidemic. Antibodies with exceptional neutralizing activity against HIV-1 may provide several advantages to traditional HIV drugs, including an improved side-effect profile, a reduced dosing frequency, and immune enhancement. The activity of these antibodies has been established in vitro by utilizing HIV-1 Env-pseudotyped viruses derived from circulating viruses but produced in 293T cells by pairing Env proteins with a backbone vector. We tested PBMC-produced circulating viruses against five anti-HIV-1 antibodies currently in clinical development. We found that the activity of these antibodies against PBMC isolates is significantly less than that against 293T Env-pseudotyped viruses. This decline varied among the antibodies tested, with some demonstrating moderate reductions in activity and others showing an almost 100-fold reduction. As the development of these antibodies progresses, it will be critical to determine how the results of different in vitro tests correspond to performance in the clinic. Copyright © 2018 Cohen et al.

Kochen-Specker vectors

International Nuclear Information System (INIS)

Pavicic, Mladen; Merlet, Jean-Pierre; McKay, Brendan; Megill, Norman D

2005-01-01

We give a constructive and exhaustive definition of Kochen-Specker (KS) vectors in a Hilbert space of any dimension as well as of all the remaining vectors of the space. KS vectors are elements of any set of orthonormal states, i.e., vectors in an n-dimensional Hilbert space, H n , n≥3, to which it is impossible to assign 1s and 0s in such a way that no two mutually orthogonal vectors from the set are both assigned 1 and that not all mutually orthogonal vectors are assigned 0. Our constructive definition of such KS vectors is based on algorithms that generate MMP diagrams corresponding to blocks of orthogonal vectors in R n , on algorithms that single out those diagrams on which algebraic (0)-(1) states cannot be defined, and on algorithms that solve nonlinear equations describing the orthogonalities of the vectors by means of statistically polynomially complex interval analysis and self-teaching programs. The algorithms are limited neither by the number of dimensions nor by the number of vectors. To demonstrate the power of the algorithms, all four-dimensional KS vector systems containing up to 24 vectors were generated and described, all three-dimensional vector systems containing up to 30 vectors were scanned, and several general properties of KS vectors were found

Elementary vectors

CERN Document Server

Wolstenholme, E Œ

1978-01-01

Elementary Vectors, Third Edition serves as an introductory course in vector analysis and is intended to present the theoretical and application aspects of vectors. The book covers topics that rigorously explain and provide definitions, principles, equations, and methods in vector analysis. Applications of vector methods to simple kinematical and dynamical problems; central forces and orbits; and solutions to geometrical problems are discussed as well. This edition of the text also provides an appendix, intended for students, which the author hopes to bridge the gap between theory and appl

A revised nomenclature for transcribed human endogenous retroviral loci

Science.gov (United States)

2011-01-01

Background Endogenous retroviruses (ERVs) and ERV-like sequences comprise 8% of the human genome. A hitherto unknown proportion of ERV loci are transcribed and thus contribute to the human transcriptome. A small proportion of these loci encode functional proteins. As the role of ERVs in normal and diseased biological processes is not yet established, transcribed ERV loci are of particular interest. As more transcribed ERV loci are likely to be identified in the near future, the development of a systematic nomenclature is important to ensure that all information on each locus can be easily retrieved. Results Here we present a revised nomenclature of transcribed human endogenous retroviral loci that sorts loci into groups based on Repbase classifications. Each symbol is of the format ERV + group symbol + unique number. Group symbols are based on a mixture of Repbase designations and well-supported symbols used in the literature. The presented guidelines will allow newly identified loci to be easily incorporated into the scheme. Conclusions The naming system will be employed by the HUGO Gene Nomenclature Committee for naming transcribed human ERV loci. We hope that the system will contribute to clarifying a certain aspect of a sometimes confusing nomenclature for human endogenous retroviruses. The presented system may also be employed for naming transcribed loci of human non-ERV repeat loci. PMID:21542922

Retroviruses as tools to study the immune system.

Science.gov (United States)

Lois, C; Refaeli, Y; Qin, X F; Van Parijs, L

2001-08-01

Retrovirus-based vectors provide an efficient means to introduce and express genes in cells of the immune system and have become a popular tool to study immune function. They are easy to manipulate and provide stable, long-term gene expression because they integrate into the genome. Current retroviral vectors do have limitations that affect their usefulness in certain applications. However, recent advances suggest a number of ways in which these vectors might be improved to extend their utility in immunological research.

Retroviral insertional mutagenesis identifies Zeb2 activation as a novel leukemogenic collaborating event in CALM-AF10 transgenic mice.

Science.gov (United States)

Caudell, David; Harper, David P; Novak, Rachel L; Pierce, Rachel M; Slape, Christopher; Wolff, Linda; Aplan, Peter D

2010-02-11

The t(10;11) translocation results in a CALM-AF10 fusion gene in a subset of leukemia patients. Expression of a CALM-AF10 transgene results in leukemia, with prolonged latency and incomplete penetrance, suggesting that additional events are necessary for leukemic transformation. CALM-AF10 mice infected with the MOL4070LTR retrovirus developed acute leukemia, and ligation-mediated polymerase chain reaction was used to identify retroviral insertions at 19 common insertion sites, including Zeb2, Nf1, Mn1, Evi1, Ift57, Mpl, Plag1, Kras, Erg, Vav1, and Gata1. A total of 26% (11 of 42) of the mice had retroviral integrations near Zeb2, a transcriptional corepressor leading to overexpression of the Zeb2-transcript. A total of 91% (10 of 11) of mice with Zeb2 insertions developed B-lineage acute lymphoblastic leukemia, suggesting that Zeb2 activation promotes the transformation of CALM-AF10 hematopoietic precursors toward B-lineage leukemias. More than half of the mice with Zeb2 integrations also had Nf1 integrations, suggesting cooperativity among CALM-AF10, Zeb2, and Ras pathway mutations. We searched for Nras, Kras, and Ptpn11 point mutations in the CALM-AF10 leukemic mice. Three mutations were identified, all of which occurred in mice with Zeb2 integrations, consistent with the hypothesis that Zeb2 and Ras pathway activation promotes B-lineage leukemic transformation in concert with CALM-AF10.

Comprehensive profiling of retroviral integration sites using target enrichment methods from historical koala samples without an assembled reference genome

Directory of Open Access Journals (Sweden)

Pin Cui

2016-03-01

Full Text Available Background. Retroviral integration into the host germline results in permanent viral colonization of vertebrate genomes. The koala retrovirus (KoRV is currently invading the germline of the koala (Phascolarctos cinereus and provides a unique opportunity for studying retroviral endogenization. Previous analysis of KoRV integration patterns in modern koalas demonstrate that they share integration sites primarily if they are related, indicating that the process is currently driven by vertical transmission rather than infection. However, due to methodological challenges, KoRV integrations have not been comprehensively characterized. Results. To overcome these challenges, we applied and compared three target enrichment techniques coupled with next generation sequencing (NGS and a newly customized sequence-clustering based computational pipeline to determine the integration sites for 10 museum Queensland and New South Wales (NSW koala samples collected between the 1870s and late 1980s. A secondary aim of this study sought to identify common integration sites across modern and historical specimens by comparing our dataset to previously published studies. Several million sequences were processed, and the KoRV integration sites in each koala were characterized. Conclusions. Although the three enrichment methods each exhibited bias in integration site retrieval, a combination of two methods, Primer Extension Capture and hybridization capture is recommended for future studies on historical samples. Moreover, identification of integration sites shows that the proportion of integration sites shared between any two koalas is quite small.

High-throughput screening using pseudotyped lentiviral particles: a strategy for the identification of HIV-1 inhibitors in a cell-based assay.

Science.gov (United States)

Garcia, Jean-Michel; Gao, Anhui; He, Pei-Lan; Choi, Joyce; Tang, Wei; Bruzzone, Roberto; Schwartz, Olivier; Naya, Hugo; Nan, Fa-Jun; Li, Jia; Altmeyer, Ralf; Zuo, Jian-Ping

2009-03-01

Two decades after its discovery the human immunodeficiency virus (HIV) is still spreading worldwide and killing millions. There are 25 drugs formally approved for HIV currently on the market, but side effects as well as the emergence of HIV strains showing single or multiple resistances to current drug-therapy are causes for concern. Furthermore, these drugs target only 4 steps of the viral cycle, hence the urgent need for new drugs and also new targets. In order to tackle this problem, we have devised a cell-based assay using lentiviral particles to look for post-entry inhibitors of HIV-1. We report here the assay development, validation as well as confirmation of the hits using both wild-type and drug-resistant HIV-1 viruses. The screening was performed on an original library, rich in natural compounds and pure molecules from Traditional Chinese Medicine pharmacopoeia, which had never been screened for anti-HIV activity. The identified hits belong to four chemical sub-families that appear to be all non-nucleoside reverse transcriptase inhibitors (NNRTIs). Secondary tests with live viruses showed that there was good agreement with pseudotyped particles, confirming the validity of this approach for high-throughput drug screens. This assay will be a useful tool that can be easily adapted to screen for inhibitors of viral entry.

Analysis of proviral integration in human mammary epithelial cell lines immortalized by retroviral infection with a temperature-sensitive SV40 T-antigen construct.

Science.gov (United States)

Stamps, A C; Davies, S C; Burman, J; O'Hare, M J

1994-06-15

A panel of eight conditionally immortal lines derived by infection of human breast epithelial cells with an amphotropic retrovirus transducing a ts mutant of SV40 large T-antigen was analyzed with respect to individual retroviral integration patterns. Each line contained multiple integration sites which were clonal and stable over extended passage. Similar integration patterns were observed between individual lines arising separately from the same stock of pre-immortal cells, suggesting a common progenitor. Retroviral integration analysis of pre-immortal cells at different stages of pre-crisis growth showed changes indicative of a progressive transition from polyclonality to clonality as the cells approached crisis. Each of the immortal lines contained a sub-set of the integration sites of their pre-immortal progenitors, with individual combinations and copy numbers of sites. Since all the cell lines appeared to originate from single foci in separate flasks, it is likely that each set arose from a common clone of pre-immortal cells as the result of separate genetic events. There was no evidence from this analysis to suggest that specific integration sites played any part either in the selection of pre-crisis clones or in the subsequent establishment of immortal lines.

Genetic manipulation of endosymbionts to control vector and vector borne diseases

Directory of Open Access Journals (Sweden)

Jay Prakash Gupta

Full Text Available Vector borne diseases (VBD are on the rise because of failure of the existing methods of control of vector and vector borne diseases and the climate change. A steep rise of VBDs are due to several factors like selection of insecticide resistant vector population, drug resistant parasite population and lack of effective vaccines against the VBDs. Environmental pollution, public health hazard and insecticide resistant vector population indicate that the insecticides are no longer a sustainable control method of vector and vector-borne diseases. Amongst the various alternative control strategies, symbiont based approach utilizing endosymbionts of arthropod vectors could be explored to control the vector and vector borne diseases. The endosymbiont population of arthropod vectors could be exploited in different ways viz., as a chemotherapeutic target, vaccine target for the control of vectors. Expression of molecules with antiparasitic activity by genetically transformed symbiotic bacteria of disease-transmitting arthropods may serve as a powerful approach to control certain arthropod-borne diseases. Genetic transformation of symbiotic bacteria of the arthropod vector to alter the vector’s ability to transmit pathogen is an alternative means of blocking the transmission of VBDs. In Indian scenario, where dengue, chikungunya, malaria and filariosis are prevalent, paratransgenic based approach can be used effectively. [Vet World 2012; 5(9.000: 571-576

Emerging vector borne diseases – incidence through vectors

Directory of Open Access Journals (Sweden)

Sara eSavic

2014-12-01

Full Text Available Vector borne diseases use to be a major public health concern only in tropical and subtropical areas, but today they are an emerging threat for the continental and developed countries also. Nowdays, in intercontinetal countries, there is a struggle with emerging diseases which have found their way to appear through vectors. Vector borne zoonotic diseases occur when vectors, animal hosts, climate conditions, pathogens and susceptible human population exist at the same time, at the same place. Global climate change is predicted to lead to an increase in vector borne infectious diseases and disease outbreaks. It could affect the range and popultion of pathogens, host and vectors, transmission season, etc. Reliable surveilance for diseases that are most likely to emerge is required. Canine vector borne diseases represent a complex group of diseases including anaplasmosis, babesiosis, bartonellosis, borreliosis, dirofilariosis, erlichiosis, leishmaniosis. Some of these diseases cause serious clinical symptoms in dogs and some of them have a zoonotic potential with an effect to public health. It is expected from veterinarians in coordination with medical doctors to play a fudamental role at primeraly prevention and then treatment of vector borne diseases in dogs. The One Health concept has to be integrated into the struggle against emerging diseases.During a four year period, from 2009-2013, a total number of 551 dog samples were analysed for vector borne diseases (borreliosis, babesiosis, erlichiosis, anaplasmosis, dirofilariosis and leishmaniasis in routine laboratory work. The analysis were done by serological tests – ELISA for borreliosis, dirofilariosis and leishmaniasis, modified Knott test for dirofilariosis and blood smear for babesiosis, erlichiosis and anaplasmosis. This number of samples represented 75% of total number of samples that were sent for analysis for different diseases in dogs. Annually, on avarege more then half of the samples

Vector-vector production in photon-photon interactions

International Nuclear Information System (INIS)

Ronan, M.T.

1988-01-01

Measurements of exclusive untagged /rho/ 0 /rho/ 0 , /rho//phi/, K/sup *//bar K//sup */, and /rho/ω production and tagged /rho/ 0 /rho/ 0 production in photon-photon interactions by the TPC/Two-Gamma experiment are reviewed. Comparisons to the results of other experiments and to models of vector-vector production are made. Fits to the data following a four quark model prescription for vector meson pair production are also presented. 10 refs., 9 figs

Rare Hadronic B Decays to Vector, Axial-Vector and Tensors

International Nuclear Information System (INIS)

Gao, Y.Y.

2011-01-01

The authors review BABAR measurements of several rare B decays, including vector-axial-vector decays B ± → φK 1 ± (1270), B ± → φ K 1 ± (1400) and B ± → b 1 # -+ρ# ± , vector-vector decays B ± → φK* ± (1410), B 0 → K* 0 (bar K)* 0 , B 0 → K*0K*0 and B 0 → K*+K*-, vector-tensor decays B ± → φK* 2 (1430) ± and φK 2 (1770)/ ± (1820), and vector-scalar decays B ± → φK* 0 (1430) ± . Understanding the observed polarization pattern requires amplitude contributions from an uncertain source.

Gypsy transposition correlates with the production of a retroviral envelope-like protein under the tissue-specific control of the Drosophila flamenco gene.

OpenAIRE

Pélisson, A; Song, S U; Prud'homme, N; Smith, P A; Bucheton, A; Corces, V G

1994-01-01

Gypsy displays striking similarities to vertebrate retroviruses, including the presence of a yet uncharacterized additional open reading frame (ORF3) and the recent evidence for infectivity. It is mobilized with high frequency in the germline of the progeny of females homozygous for the flamenco permissive mutation. We report the characterization of a gypsy subgenomic ORF3 RNA encoding typical retroviral envelope proteins. In females, env expression is strongly repressed by one copy of the no...

Vector analysis

CERN Document Server

Brand, Louis

2006-01-01

The use of vectors not only simplifies treatments of differential geometry, mechanics, hydrodynamics, and electrodynamics, but also makes mathematical and physical concepts more tangible and easy to grasp. This text for undergraduates was designed as a short introductory course to give students the tools of vector algebra and calculus, as well as a brief glimpse into these subjects' manifold applications. The applications are developed to the extent that the uses of the potential function, both scalar and vector, are fully illustrated. Moreover, the basic postulates of vector analysis are brou

Human hematopoietic cell culture, transduction, and analyses

DEFF Research Database (Denmark)

Bonde, Jesper; Wirthlin, Louisa; Kohn, Donald B

2008-01-01

This unit provides methods for introducing genes into human hematopoietic progenitor cells. The Basic Protocol describes isolation of CD34(+) cells, transduction of these cells with a retroviral vector on fibronectin-coated plates, assaying the efficiency of transduction, and establishing long-te...

Vectors and Rotations in 3-Dimensions: Vector Algebra for the C++ Programmer

Science.gov (United States)

2016-12-01

release; distribution is unlimited. 1. Introduction This report describes 2 C++ classes: a Vector class for performing vector algebra in 3-dimensional...ARL-TR-7894•DEC 2016 US Army Research Laboratory Vectors and Rotations in 3-Dimensions:Vector Algebra for the C++ Programmer by Richard Saucier...Army Research Laboratory Vectors and Rotations in 3-Dimensions:Vector Algebra for the C++ Programmer by Richard Saucier Survivability/Lethality

The brain-specific factor FEZ1 is a determinant of neuronal susceptibility to HIV-1 infection.

LENUS (Irish Health Repository)

Haedicke, Juliane

2009-08-18

Neurons are one of the few cell types in the human body that do not support HIV type-1 (HIV-1) replication. Although the lack of key receptors is a major obstacle to infection, studies suggest that additional functions inhibit virus replication to explain the exquisite resistance of neurons to HIV-1. However, specific neuronal factors that may explain this resistance remain to be discovered. In a screen for antiviral factors using a fibroblast line chemically mutagenized and selected for resistance to retroviral infection, we recently identified induction of rat FEZ1 (fasciculation and elongation protein zeta-1), a brain-specific protein, as the cause of this resistance. When exogenously expressed in nonneuronal cell lines rat FEZ1 blocked nuclear entry of retroviral DNA. Here, we demonstrate that among human brain cells, neurons naturally express high levels of FEZ1 compared to astrocytes or microglia cells and are correspondingly less susceptible to infection with pseudotyped HIV-1 that bypasses receptor-mediated viral entry. Demonstrating that endogenous FEZ1 was functionally important in the resistance of neurons to HIV-1 infection, siRNA-mediated knockdown of endogenous FEZ1 increased the infectivity of neurons while sensitive brain cell types like microglia became more resistant upon FEZ1 overexpression. In addition, FEZ1 expression was not induced in response to IFN treatment. As such, in contrast to other widely expressed, IFN-inducible antiviral factors, FEZ1 appears to represent a unique neuron-specific determinant of cellular susceptibility to infection in a cell type that is naturally resistant to HIV-1.

Identifying activated T cells in reconstituted RAG deficient mice using retrovirally transduced Pax5 deficient pro-B cells.

Directory of Open Access Journals (Sweden)

Nadesan Gajendran

Full Text Available Various methods have been used to identify activated T cells such as binding of MHC tetramers and expression of cell surface markers in addition to cytokine-based assays. In contrast to these published methods, we here describe a strategy to identify T cells that respond to any antigen and track the fate of these activated T cells. We constructed a retroviral double-reporter construct with enhanced green fluorescence protein (EGFP and a far-red fluorescent protein from Heteractis crispa (HcRed. LTR-driven EGFP expression was used to enrich and identify transduced cells, while HcRed expression is driven by the CD40Ligand (CD40L promoter, which is inducible and enables the identification and cell fate tracing of T cells that have responded to infection/inflammation. Pax5 deficient pro-B cells that can give rise to different hematopoietic cells like T cells, were retrovirally transduced with this double-reporter cassette and were used to reconstitute the T cell pool in RAG1 deficient mice that lack T and B cells. By using flow cytometry and histology, we identified activated T cells that had developed from Pax5 deficient pro-B cells and responded to infection with the bacterial pathogen Listeria monocytogenes. Microscopic examination of organ sections allowed visual identification of HcRed-expressing cells. To further characterize the immune response to a given stimuli, this strategy can be easily adapted to identify other cells of the hematopoietic system that respond to infection/inflammation. This can be achieved by using an inducible reporter, choosing the appropriate promoter, and reconstituting mice lacking cells of interest by injecting gene-modified Pax5 deficient pro-B cells.

Measurement of Charmless B to Vector-Vector decays at BaBar

International Nuclear Information System (INIS)

Olaiya, Emmanuel

2011-01-01

The authors present results of B → vector-vector (VV) and B → vector-axial vector (VA) decays B 0 → φX(X = φ,ρ + or ρ 0 ), B + → φK (*)+ , B 0 → K*K*, B 0 → ρ + b 1 - and B + → K* 0 α 1 + . The largest dataset used for these results is based on 465 x 10 6 Υ(4S) → B(bar B) decays, collected with the BABAR detector at the PEP-II B meson factory located at the Stanford Linear Accelerator Center (SLAC). Using larger datasets, the BABAR experiment has provided more precise B → VV measurements, further supporting the smaller than expected longitudinal polarization fraction of B → φK*. Additional B meson to vector-vector and vector-axial vector decays have also been studied with a view to shedding light on the polarization anomaly. Taking into account the available errors, we find no disagreement between theory and experiment for these additional decays.

Fulltext PDF

Indian Academy of Sciences (India)

2013-04-25

Apr 25, 2013 ... ... of Surgery Research, State Key Laboratory of Trauma, Burns and Combined Injury,. Research Institute for Traffic Medicine, Daping Hospital, Third Military Medical University, ..... sored by Department of Human Resources and Social Security ... 2006 Development of a new bicistronic retroviral vector with.

Vectorization of KENO IV code and an estimate of vector-parallel processing

International Nuclear Information System (INIS)

Asai, Kiyoshi; Higuchi, Kenji; Katakura, Jun-ichi; Kurita, Yutaka.

1986-10-01

The multi-group criticality safety code KENO IV has been vectorized and tested on FACOM VP-100 vector processor. At first the vectorized KENO IV on a scalar processor became slower than the original one by a factor of 1.4 because of the overhead introduced by the vectorization. Making modifications of algorithms and techniques for vectorization, the vectorized version has become faster than the original one by a factor of 1.4 and 3.0 on the vector processor for sample problems of complex and simple geometries, respectively. For further speedup of the code, some improvements on compiler and hardware, especially on addition of Monte Carlo pipelines to the vector processor, are discussed. Finally a pipelined parallel processor system is proposed and its performance is estimated. (author)

Retroviral gene transfer of an antisense construct against membrane type 1 matrix metalloproteinase reduces the invasiveness of rheumatoid arthritis synovial fibroblasts.

Science.gov (United States)

Rutkauskaite, Edita; Volkmer, Dagmar; Shigeyama, Yukio; Schedel, Jörg; Pap, Geza; Müller-Ladner, Ulf; Meinecke, Ingmar; Alexander, Dorothea; Gay, Renate E; Drynda, Susanne; Neumann, Wolfram; Michel, Beat A; Aicher, Wilhelm K; Gay, Steffen; Pap, Thomas

2005-07-01

Membrane type 1 matrix metalloproteinase (MT1-MMP) is expressed prominently in rheumatoid arthritis synovial fibroblasts (RASFs), but the specific contribution of MT1-MMP to fibroblast-mediated destruction of articular cartilage is incompletely understood. This study used gene transfer of an antisense expression construct to assess the effects of MT1-MMP inhibition on the invasiveness of RASFs. Retroviral gene transfer of a pLXIN vector-based antisense RNA expression construct (MT1-MMPalphaS) to MT1-MMP was used to stably transduce RASFs. Levels of MT1-MMP RNA and protein were determined by quantitative polymerase chain reaction, Western blotting, and immunocytochemistry in MT1-MMPalphaS-transduced RASFs as well as in control cells, with monitoring for 60 days. The effects of MT1-MMPalphaS on the invasiveness of RASFs were analyzed in the SCID mouse co-implantation model of RA. MT1-MMPalphaS-transduced RASFs produced high levels of antisense RNA that exceeded endogenous levels of MT1-MMP messenger RNA by 15-fold and resulted in a down-regulation of MT1-MMP at the protein level. Inhibition of MT1-MMP production was maintained for 60 days and significantly reduced the invasiveness of RASFs in the SCID mouse model. Whereas prominent invasion into cartilage by non-transduced and mock-transduced RASFs was observed (mean invasion scores 3.0 and 3.1, respectively), MT1-MMPalphaS-transduced cells showed only moderate invasiveness (mean invasion score 1.8; P < 0.05). The data demonstrate that an antisense RNA expression construct against MT1-MMP can be generated and expressed in RASFs for at least 60 days. Inhibition of MT1-MMP significantly reduces the cartilage degradation by RASFs.

Versatile generation of optical vector fields and vector beams using a non-interferometric approach.

Science.gov (United States)

Tripathi, Santosh; Toussaint, Kimani C

2012-05-07

We present a versatile, non-interferometric method for generating vector fields and vector beams which can produce all the states of polarization represented on a higher-order Poincaré sphere. The versatility and non-interferometric nature of this method is expected to enable exploration of various exotic properties of vector fields and vector beams. To illustrate this, we study the propagation properties of some vector fields and find that, in general, propagation alters both their intensity and polarization distribution, and more interestingly, converts some vector fields into vector beams. In the article, we also suggest a modified Jones vector formalism to represent vector fields and vector beams.

Vectorized Monte Carlo

International Nuclear Information System (INIS)

Brown, F.B.

1981-01-01

Examination of the global algorithms and local kernels of conventional general-purpose Monte Carlo codes shows that multigroup Monte Carlo methods have sufficient structure to permit efficient vectorization. A structured multigroup Monte Carlo algorithm for vector computers is developed in which many particle events are treated at once on a cell-by-cell basis. Vectorization of kernels for tracking and variance reduction is described, and a new method for discrete sampling is developed to facilitate the vectorization of collision analysis. To demonstrate the potential of the new method, a vectorized Monte Carlo code for multigroup radiation transport analysis was developed. This code incorporates many features of conventional general-purpose production codes, including general geometry, splitting and Russian roulette, survival biasing, variance estimation via batching, a number of cutoffs, and generalized tallies of collision, tracklength, and surface crossing estimators with response functions. Predictions of vectorized performance characteristics for the CYBER-205 were made using emulated coding and a dynamic model of vector instruction timing. Computation rates were examined for a variety of test problems to determine sensitivities to batch size and vector lengths. Significant speedups are predicted for even a few hundred particles per batch, and asymptotic speedups by about 40 over equivalent Amdahl 470V/8 scalar codes arepredicted for a few thousand particles per batch. The principal conclusion is that vectorization of a general-purpose multigroup Monte Carlo code is well worth the significant effort required for stylized coding and major algorithmic changes

Inhibition of tolbutamide 4-methylhydroxylation by a series of non-steroidal anti-inflammatory drugs in V79-NH cells expressing human cytochrome P4502C10

NARCIS (Netherlands)

Kappers, W.A.; Groene, E.M. de; Kleij, L.A.; Witkamp, R.F.; Zweers-Zeilmaker, W.M.; Feron, V.J.; Horbach, G.J.

1996-01-01

1. To study the role of cytochrome P4502C10 in the metabolism of the non-steroidal antiinflammatory drugs (NSAIDs) diclofenac, phenylbutazone, fenoprofen, ibuprofen, flurbiprofen, ketoprofen and naproxen, a cell line was developed stably expressing CYP2C10 cDNA. A retroviral vector construct,

Genetic modification of human B-cell development: B-cell development is inhibited by the dominant negative helix loop helix factor Id3

NARCIS (Netherlands)

Jaleco, A. C.; Stegmann, A. P.; Heemskerk, M. H.; Couwenberg, F.; Bakker, A. Q.; Weijer, K.; Spits, H.

1999-01-01

Transgenic and gene targeted mice have contributed greatly to our understanding of the mechanisms underlying B-cell development. We describe here a model system that allows us to apply molecular genetic techniques to the analysis of human B-cell development. We constructed a retroviral vector with a

Isolation, characterization, and genetic complementation of a cellular mutant resistant to retroviral infection

Science.gov (United States)

Agarwal, Sumit; Harada, Josephine; Schreifels, Jeffrey; Lech, Patrycja; Nikolai, Bryan; Yamaguchi, Tomoyuki; Chanda, Sumit K.; Somia, Nikunj V.

2006-01-01

By using a genetic screen, we have isolated a mammalian cell line that is resistant to infection by retroviruses that are derived from the murine leukemia virus, human immunodeficiency virus type 1, and feline immunodeficiency virus. We demonstrate that the cell line is genetically recessive for the resistance, and hence it is lacking a factor enabling infection by retroviruses. The block to infection is early in the life cycle, at the poorly understood uncoating stage. We implicate the proteasome at uncoating by completely rescuing the resistant phenotype with the proteasomal inhibitor MG-132. We further report on the complementation cloning of a gene (MRI, modulator of retrovirus infection) that can also act to reverse the inhibition of infection in the mutant cell line. These data implicate a role for the proteasome during uncoating, and they suggest that MRI is a regulator of this activity. Finally, we reconcile our findings and other published data to suggest a model for the involvement of the proteasome in the early phase of the retroviral life cycle. PMID:17043244

Vector Network Coding

OpenAIRE

Ebrahimi, Javad; Fragouli, Christina

2010-01-01

We develop new algebraic algorithms for scalar and vector network coding. In vector network coding, the source multicasts information by transmitting vectors of length L, while intermediate nodes process and combine their incoming packets by multiplying them with L X L coding matrices that play a similar role as coding coefficients in scalar coding. Our algorithms for scalar network jointly optimize the employed field size while selecting the coding coefficients. Similarly, for vector co...

Mutations in the catalytic core or the C-terminus of murine leukemia virus (MLV) integrase disrupt virion infectivity and exert diverse effects on reverse transcription

International Nuclear Information System (INIS)

Steinrigl, Adolf; Nosek, Dagmara; Ertl, Reinhard; Guenzburg, Walter H.; Salmons, Brian; Klein, Dieter

2007-01-01

Understanding of the structures and functions of the retroviral integrase (IN), a key enzyme in the viral replication cycle, is essential for developing antiretroviral treatments and facilitating the development of safer gene therapy vehicles. Thus, four MLV IN-mutants were constructed in the context of a retroviral vector system, harbouring either a substitution in the catalytic centre, deletions in the C-terminus, or combinations of both modifications. IN-mutants were tested for their performance in different stages of the viral replication cycle: RNA-packaging; RT-activity; transient and stable infection efficiency; dynamics of reverse transcription and nuclear entry. All mutant vectors packaged viral RNA with wild-type efficiencies and displayed only slight reductions in RT-activity. Deletion of either the IN C-terminus alone, or in addition to part of the catalytic domain exerted contrasting effects on intracellular viral DNA levels, implying that IN influences reverse transcription in more than one direction

Vector independent transmission of the vector-borne bluetongue virus.

Science.gov (United States)

van der Sluijs, Mirjam Tineke Willemijn; de Smit, Abraham J; Moormann, Rob J M

2016-01-01

Bluetongue is an economically important disease of ruminants. The causative agent, Bluetongue virus (BTV), is mainly transmitted by insect vectors. This review focuses on vector-free BTV transmission, and its epizootic and economic consequences. Vector-free transmission can either be vertical, from dam to fetus, or horizontal via direct contract. For several BTV-serotypes, vertical (transplacental) transmission has been described, resulting in severe congenital malformations. Transplacental transmission had been mainly associated with live vaccine strains. Yet, the European BTV-8 strain demonstrated a high incidence of transplacental transmission in natural circumstances. The relevance of transplacental transmission for the epizootiology is considered limited, especially in enzootic areas. However, transplacental transmission can have a substantial economic impact due to the loss of progeny. Inactivated vaccines have demonstrated to prevent transplacental transmission. Vector-free horizontal transmission has also been demonstrated. Since direct horizontal transmission requires close contact of animals, it is considered only relevant for within-farm spreading of BTV. The genetic determinants which enable vector-free transmission are present in virus strains circulating in the field. More research into the genetic changes which enable vector-free transmission is essential to better evaluate the risks associated with outbreaks of new BTV serotypes and to design more appropriate control measures.

VISPA2: a scalable pipeline for high-throughput identification and annotation of vector integration sites.

Science.gov (United States)

Spinozzi, Giulio; Calabria, Andrea; Brasca, Stefano; Beretta, Stefano; Merelli, Ivan; Milanesi, Luciano; Montini, Eugenio

2017-11-25

Bioinformatics tools designed to identify lentiviral or retroviral vector insertion sites in the genome of host cells are used to address the safety and long-term efficacy of hematopoietic stem cell gene therapy applications and to study the clonal dynamics of hematopoietic reconstitution. The increasing number of gene therapy clinical trials combined with the increasing amount of Next Generation Sequencing data, aimed at identifying integration sites, require both highly accurate and efficient computational software able to correctly process "big data" in a reasonable computational time. Here we present VISPA2 (Vector Integration Site Parallel Analysis, version 2), the latest optimized computational pipeline for integration site identification and analysis with the following features: (1) the sequence analysis for the integration site processing is fully compliant with paired-end reads and includes a sequence quality filter before and after the alignment on the target genome; (2) an heuristic algorithm to reduce false positive integration sites at nucleotide level to reduce the impact of Polymerase Chain Reaction or trimming/alignment artifacts; (3) a classification and annotation module for integration sites; (4) a user friendly web interface as researcher front-end to perform integration site analyses without computational skills; (5) the time speedup of all steps through parallelization (Hadoop free). We tested VISPA2 performances using simulated and real datasets of lentiviral vector integration sites, previously obtained from patients enrolled in a hematopoietic stem cell gene therapy clinical trial and compared the results with other preexisting tools for integration site analysis. On the computational side, VISPA2 showed a > 6-fold speedup and improved precision and recall metrics (1 and 0.97 respectively) compared to previously developed computational pipelines. These performances indicate that VISPA2 is a fast, reliable and user-friendly tool for

VectorBase

Data.gov (United States)

U.S. Department of Health & Human Services — VectorBase is a Bioinformatics Resource Center for invertebrate vectors. It is one of four Bioinformatics Resource Centers funded by NIAID to provide web-based...

Custodial vector model

DEFF Research Database (Denmark)

Becciolini, Diego; Franzosi, Diogo Buarque; Foadi, Roshan

2015-01-01

We analyze the Large Hadron Collider (LHC) phenomenology of heavy vector resonances with a $SU(2)_L\\times SU(2)_R$ spectral global symmetry. This symmetry partially protects the electroweak S-parameter from large contributions of the vector resonances. The resulting custodial vector model spectrum...

Experimental demonstration of vector E x vector B plasma divertor

International Nuclear Information System (INIS)

Strait, E.J.; Kerst, D.W.; Sprott, J.C.

1977-01-01

The vector E x vector B drift due to an applied radial electric field in a tokamak with poloidal divertor can speed the flow of plasma out of the scrape-off region, and provide a means of externally controlling the flow rate and thus the width of the density fall-off. An experiment in the Wisconsin levitated toroidal octupole, using vector E x vector B drifts alone, demonstrates divertor-like behavior, including 70% reduction of plasma density near the wall and 40% reduction of plasma flux to the wall, with no adverse effects on confinement of the main plasma

Rotations with Rodrigues' vector

International Nuclear Information System (INIS)

Pina, E

2011-01-01

The rotational dynamics was studied from the point of view of Rodrigues' vector. This vector is defined here by its connection with other forms of parametrization of the rotation matrix. The rotation matrix was expressed in terms of this vector. The angular velocity was computed using the components of Rodrigues' vector as coordinates. It appears to be a fundamental matrix that is used to express the components of the angular velocity, the rotation matrix and the angular momentum vector. The Hamiltonian formalism of rotational dynamics in terms of this vector uses the same matrix. The quantization of the rotational dynamics is performed with simple rules if one uses Rodrigues' vector and similar formal expressions for the quantum operators that mimic the Hamiltonian classical dynamics.

Violation of vector dominance in the vector manifestation

International Nuclear Information System (INIS)

Sasaki, Chihiro

2003-01-01

The vector manifestation (VM) is a new pattern for realizing the chiral symmetry in QCD. In the VM, the massless vector meson becomes the chiral partner of pion at the critical point, in contrast with the restoration based on the linear sigma model. Including the intrinsic temperature dependences of the parameters of the hidden local symmetry (HLS) Lagrangian determined from the underlying QCD through the Wilsonian matching together with the hadronic thermal corrections, we present a new prediction of the VM on the direct photon-π-π coupling which measures the validity of the vector dominance (VD) of the electromagnetic form factor of the pion. We find that the VD is largely violated at the critical temperature, which indicates that the assumption of the VD made in several analysis on the dilepton spectra in hot matter may need to be weakened for consistently including the effect of the dropping mass of the vector meson. (author)

Genome-wide retroviral insertional tagging of genes involved in cancer in Cdkn2a-deficient mice

DEFF Research Database (Denmark)

Lund, Anders H; Turner, Geoffrey; Trubetskoy, Alla

2002-01-01

We have used large-scale insertional mutagenesis to identify functional landmarks relevant to cancer in the recently completed mouse genome sequence. We infected Cdkn2a(-/-) mice with Moloney murine leukemia virus (MoMuLV) to screen for loci that can participate in tumorigenesis in collaboration...... retroviral integration sites and mapped them against the mouse genome sequence databases from Celera and Ensembl. In addition to 17 insertions targeting gene loci known to be cancer-related, we identified a total of 37 new common insertion sites (CISs), of which 8 encode components of signaling pathways...... that are involved in cancer. The effectiveness of large-scale insertional mutagenesis in a sensitized genetic background is demonstrated by the preference for activation of MAP kinase signaling, collaborating with Cdkn2a loss in generating the lymphoid and myeloid tumors. Collectively, our results show that large...

Measurement of K/sub NN/, K/sub LL/ in p vector d → n vector X and p vector 9Be → n vector X at 800 MeV

International Nuclear Information System (INIS)

Riley, P.J.; Hollas, C.L.; Newsom, C.R.

1980-01-01

The spin transfer parameters, K/sub NN/ and K/sub LL/, have been measured in p vector d → n vector X and p vector 9 Be → n vector X at 0 0 and 800 MeV. The rather large values of K/sub LL/ demonstrate that this transfer mechanism will provide a useful source of polarized neutrons at LAMPF energies

Accelerated generation of human induced pluripotent stem cells with retroviral transduction and chemical inhibitors under physiological hypoxia

Energy Technology Data Exchange (ETDEWEB)

Shimada, Hidenori [Department of Bioartificial Organs, Institute for Frontier Medical Sciences, Kyoto University, 53 Kawaharacho, Shogoin, Sakyoku, Kyoto 606-8507 (Japan); Hashimoto, Yoshiya [Department of Biomaterials, Osaka Dental University, 8-1, Hanazonocho, Kuzuha, Hirakatashi, Osaka 573-1121 (Japan); Nakada, Akira; Shigeno, Keiji [Department of Bioartificial Organs, Institute for Frontier Medical Sciences, Kyoto University, 53 Kawaharacho, Shogoin, Sakyoku, Kyoto 606-8507 (Japan); Nakamura, Tatsuo, E-mail: nakamura@frontier.kyoto-u.ac.jp [Department of Bioartificial Organs, Institute for Frontier Medical Sciences, Kyoto University, 53 Kawaharacho, Shogoin, Sakyoku, Kyoto 606-8507 (Japan)

2012-01-13

Highlights: Black-Right-Pointing-Pointer Very rapid generation of human iPS cells under optimized conditions. Black-Right-Pointing-Pointer Five chemical inhibitors under hypoxia boosted reprogramming. Black-Right-Pointing-Pointer We performed genome-wide DNA methylation analysis. -- Abstract: Induced pluripotent stem (iPS) cells are generated from somatic cells by the forced expression of a defined set of pluripotency-associated transcription factors. Human iPS cells can be propagated indefinitely, while maintaining the capacity to differentiate into all cell types in the body except for extra-embryonic tissues. This technology not only represents a new way to use individual-specific stem cells for regenerative medicine but also constitutes a novel method to obtain large amounts of disease-specific cells for biomedical research. Despite their great potential, the long reprogramming process (up to 1 month) remains one of the most significant challenges facing standard virus-mediated methodology. In this study, we report the accelerated generation of human iPS cells from adipose-derived stem (ADS) cells, using a new combination of chemical inhibitors under a setting of physiological hypoxia in conjunction with retroviral transduction of Oct4, Sox2, Klf4, and L-Myc. Under optimized conditions, we observed human embryonic stem (ES)-like cells as early as 6 days after the initial retroviral transduction. This was followed by the emergence of fully reprogrammed cells bearing Tra-1-81-positive and DsRed transgene-silencing properties on day 10. The resulting cell lines resembled human ES cells in many respects including proliferation rate, morphology, pluripotency-associated markers, global gene expression patterns, genome-wide DNA methylation states, and the ability to differentiate into all three of the germ layers, both in vitro and in vivo. Our method, when combined with chemical inhibitors under conditions of physiological hypoxia, offers a powerful tool for rapidly

Accelerated generation of human induced pluripotent stem cells with retroviral transduction and chemical inhibitors under physiological hypoxia

International Nuclear Information System (INIS)

Shimada, Hidenori; Hashimoto, Yoshiya; Nakada, Akira; Shigeno, Keiji; Nakamura, Tatsuo

2012-01-01

Highlights: ► Very rapid generation of human iPS cells under optimized conditions. ► Five chemical inhibitors under hypoxia boosted reprogramming. ► We performed genome-wide DNA methylation analysis. -- Abstract: Induced pluripotent stem (iPS) cells are generated from somatic cells by the forced expression of a defined set of pluripotency-associated transcription factors. Human iPS cells can be propagated indefinitely, while maintaining the capacity to differentiate into all cell types in the body except for extra-embryonic tissues. This technology not only represents a new way to use individual-specific stem cells for regenerative medicine but also constitutes a novel method to obtain large amounts of disease-specific cells for biomedical research. Despite their great potential, the long reprogramming process (up to 1 month) remains one of the most significant challenges facing standard virus-mediated methodology. In this study, we report the accelerated generation of human iPS cells from adipose-derived stem (ADS) cells, using a new combination of chemical inhibitors under a setting of physiological hypoxia in conjunction with retroviral transduction of Oct4, Sox2, Klf4, and L-Myc. Under optimized conditions, we observed human embryonic stem (ES)-like cells as early as 6 days after the initial retroviral transduction. This was followed by the emergence of fully reprogrammed cells bearing Tra-1-81-positive and DsRed transgene-silencing properties on day 10. The resulting cell lines resembled human ES cells in many respects including proliferation rate, morphology, pluripotency-associated markers, global gene expression patterns, genome-wide DNA methylation states, and the ability to differentiate into all three of the germ layers, both in vitro and in vivo. Our method, when combined with chemical inhibitors under conditions of physiological hypoxia, offers a powerful tool for rapidly generating bona fide human iPS cells and facilitates the application of i

Raster images vectorization system

OpenAIRE

Genytė, Jurgita

2006-01-01

The problem of raster images vectorization was analyzed and researched in this work. Existing vectorization systems are quite expensive, the results are inaccurate, and the manual vectorization of a large number of drafts is impossible. That‘s why our goal was to design and develop a new raster images vectorization system using our suggested automatic vectorization algorithm and the way to record results in a new universal vectorial file format. The work consists of these main parts: analysis...

Vectorization of phase space Monte Carlo code in FACOM vector processor VP-200

International Nuclear Information System (INIS)

Miura, Kenichi

1986-01-01

This paper describes the vectorization techniques for Monte Carlo codes in Fujitsu's Vector Processor System. The phase space Monte Carlo code FOWL is selected as a benchmark, and scalar and vector performances are compared. The vectorized kernel Monte Carlo routine which contains heavily nested IF tests runs up to 7.9 times faster in vector mode than in scalar mode. The overall performance improvement of the vectorized FOWL code over the original scalar code reaches 3.3. The results of this study strongly indicate that supercomputer can be a powerful tool for Monte Carlo simulations in high energy physics. (Auth.)

Generation of Directly Converted Human Osteoblasts That Are Free of Exogenous Gene and Xenogenic Protein.

Science.gov (United States)

Yamamoto, Kenta; Sato, Yoshiki; Honjo, Kenichi; Ichioka, Hiroaki; Oseko, Fumishige; Sowa, Yoshihiro; Yamamoto, Toshiro; Kanamura, Narisato; Kishida, Tsunao; Mazda, Osam

2016-11-01

Generation of osteoblasts from human somatic cells may be applicable in an effective transplantation therapy against bone diseases. Recently we established a procedure to directly convert human fibroblasts into osteoblasts by transducing some transcription factor genes via retroviral vectors. However, retroviral vector-mediated transduction may potentially cause tumor formation from the infected cells, thus a non-viral gene transfection method may be more preferable for preparation of osteoblasts to be used for transplantation therapy. Here, we constructed a plasmid vector encoding Oct4, Osterix, and L-Myc that were an appropriate combination of transcription factors for this purpose. Osteoblast-like phenotypes including high alkaline phosphatase (ALP) activity, bone matrix production and osteoblast-specific gene expression were induced in normal human fibroblasts that were transfected with the plasmid followed by culturing in osteogenic medium. The plasmid-driven directly converted osteoblasts (p-dOBs) were obtained even in the absence of a xenogenic protein. The plasmid vector sequence had fallen out of the p-dOBs. The cells formed deposition of calcified bodies in situ after transplantation into mice. These results strongly suggest that p-dOBs can be put into practical use for a novel cell-based therapy against bone diseases. J. Cell. Biochem. 117: 2538-2545, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Gene therapy/bone marrow transplantation in ADA-deficient mice: roles of enzyme-replacement therapy and cytoreduction.

Science.gov (United States)

Carbonaro, Denise A; Jin, Xiangyang; Wang, Xingchao; Yu, Xiao-Jin; Rozengurt, Nora; Kaufman, Michael L; Wang, Xiaoyan; Gjertson, David; Zhou, Yang; Blackburn, Michael R; Kohn, Donald B

2012-11-01

Gene therapy (GT) for adenosine deaminase-deficient severe combined immune deficiency (ADA-SCID) can provide significant long-term benefit when patients are given nonmyeloablative conditioning and ADA enzyme-replacement therapy (ERT) is withheld before autologous transplantation of γ-retroviral vector-transduced BM CD34+ cells. To determine the contributions of conditioning and discontinuation of ERT to the therapeutic effects, we analyzed these factors in Ada gene knockout mice (Ada(-/-)). Mice were transplanted with ADA-deficient marrow transduced with an ADA-expressing γ-retroviral vector without preconditioning or after 200 cGy or 900 cGy total-body irradiation and evaluated after 4 months. In all tissues analyzed, vector copy numbers (VCNs) were 100- to 1000-fold greater in mice receiving 900 cGy compared with 200 cGy (P < .05). In mice receiving 200 cGy, VCN was similar whether ERT was stopped or given for 1 or 4 months after GT. In unconditioned mice, there was decreased survival with and without ERT, and VCN was very low to undetectable. When recipients were conditioned with 200 cGy and received transduced lineage-depleted marrow, only recipients receiving ERT (1 or 4 months) had detectable vector sequences in thymocytes. In conclusion, cytoreduction is important for the engraftment of gene-transduced HSC, and short-term ERT after GT did not diminish the capacity of gene-corrected cells to engraft and persist.

A new system for parallel drug screening against multiple-resistant HIV mutants based on lentiviral self-inactivating (SIN vectors and multi-colour analyses

Directory of Open Access Journals (Sweden)

Prokofjeva Maria M

2013-01-01

Full Text Available Abstract Background Despite progress in the development of combined antiretroviral therapies (cART, HIV infection remains a significant challenge for human health. Current problems of cART include multi-drug-resistant virus variants, long-term toxicity and enormous treatment costs. Therefore, the identification of novel effective drugs is urgently needed. Methods We developed a straightforward screening approach for simultaneously evaluating the sensitivity of multiple HIV gag-pol mutants to antiviral drugs in one assay. Our technique is based on multi-colour lentiviral self-inactivating (SIN LeGO vector technology. Results We demonstrated the successful use of this approach for screening compounds against up to four HIV gag-pol variants (wild-type and three mutants simultaneously. Importantly, the technique was adapted to Biosafety Level 1 conditions by utilising ecotropic pseudotypes. This allowed upscaling to a large-scale screening protocol exploited by pharmaceutical companies in a successful proof-of-concept experiment. Conclusions The technology developed here facilitates fast screening for anti-HIV activity of individual agents from large compound libraries. Although drugs targeting gag-pol variants were used here, our approach permits screening compounds that target several different, key cellular and viral functions of the HIV life-cycle. The modular principle of the method also allows the easy exchange of various mutations in HIV sequences. In conclusion, the methodology presented here provides a valuable new approach for the identification of novel anti-HIV drugs.

The First Synthesis and Anti-retroviral Activity of 5',5'-Difluoro-3'-Hydroxy-Apiosyl Nucleoside Cyclomonophosphonic Acid Analogs

Energy Technology Data Exchange (ETDEWEB)

Kim, Seyeon; Hong, Joon Hee [Chosun University, Gwangju (Korea, Republic of)

2016-04-15

The first synthesis of novel 5',5'-difluoro-30-hydroxy apiose nucleoside cyclomonophosphonic acid analogs was performed as potent anti-retroviral agents. Phosphonation was performed by direct displacement of a triflate intermediate with diethyl(lithiodifluoromethyl) phosphonate to give the corresponding(α, α-difluoroalkyl) phosphonate. Condensation successfully proceeded from a glycosyl donor with persilylated bases to yield the nucleoside phosphonate analogs. Deprotection of diethyl phosphonates provided the target nucleoside cyclomonophosphonic acid analogs. The synthesized nucleoside analogs were subjected to anti-viral screening against the human immunodeficiency virus-1 (HIV-1). Cytosine analogs show significant anti-HIV activity.

An audit on virological efficacy of anti-retroviral therapy in a specialist infectious disease clinic.

LENUS (Irish Health Repository)

Reyad, A

2009-06-01

We have assessed the efficacy of anti retroviral therapy (ART) using undetectable viral load (VL) (<50 RNA copies\\/ml) as a marker of virological success, in patients who have Human Immunodeficiency Virus (HIV) attending the Department of Infectious Disease. A cross-sectional review of patients\\' case notes was used to obtain their demographics and treatment details. 79% (253) of the hospital case notes of clinic population was available for analysis, which represents 90% of those receiving ART in the clinic. 166\\/253 of the cohort were receiving treatment at the time of this study and 95% (157\\/166) of these were on treatment for greater than 6 months. The total virological success rate is 93%, which is comparable to other centres and are as good as those from published clinical trials. 56% of those on therapy who have virological failure were Intravenous Drug Users (IVDUs). Case by case investigation for those with treatment failure is warranted.

CD4 expression on EL4 cells as an epiphenomenon of retroviral transduction and selection.

Science.gov (United States)

Logan, Grant J; Spinoulas, Afroditi; Alexander, Stephen I; Smythe, Jason A; Alexander, Ian E

2004-04-01

The EL4 murine tumour cell line, isolated from a chemically induced lymphoma over 50 years ago, has been extensively exploited in immunological research. The conclusions drawn from many of these studies have been based on the presumption that EL4 cells maintain a stable phenotype during experimental manipulation. To the contrary, we have observed 100-fold greater expression of cell surface CD4 (CD4(high)) on a subpopulation of EL4 cells following retroviral transduction and G418 selection when compared with unmodified populations. Although the mechanism responsible for this effect remains to be elucidated, the unexpected expression of CD4, a molecule that functions as both a coreceptor with the T-cell receptor and ligand for the pro-inflammatory cytokine IL-16, has the potential to influence experimental outcomes. Upregulation of CD4 should be excluded when EL4 cells are utilized in experiments requiring a consistent immuno-phenotype.

Vector grammars and PN machines

Institute of Scientific and Technical Information of China (English)

蒋昌俊

1996-01-01

The concept of vector grammars under the string semantic is introduced.The dass of vector grammars is given,which is similar to the dass of Chomsky grammars.The regular vector grammar is divided further.The strong and weak relation between the vector grammar and scalar grammar is discussed,so the spectrum system graph of scalar and vector grammars is made.The equivalent relation between the regular vector grammar and Petri nets (also called PN machine) is pointed.The hybrid PN machine is introduced,and its language is proved equivalent to the language of the context-free vector grammar.So the perfect relation structure between vector grammars and PN machines is formed.

Vector velocimeter

DEFF Research Database (Denmark)

2012-01-01

The present invention relates to a compact, reliable and low-cost vector velocimeter for example for determining velocities of particles suspended in a gas or fluid flow, or for determining velocity, displacement, rotation, or vibration of a solid surface, the vector velocimeter comprising a laser...

Cloning vector

Science.gov (United States)

Guilfoyle, Richard A.; Smith, Lloyd M.

1994-01-01

A vector comprising a filamentous phage sequence containing a first copy of filamentous phage gene X and other sequences necessary for the phage to propagate is disclosed. The vector also contains a second copy of filamentous phage gene X downstream from a promoter capable of promoting transcription in a bacterial host. In a preferred form of the present invention, the filamentous phage is M13 and the vector additionally includes a restriction endonuclease site located in such a manner as to substantially inactivate the second gene X when a DNA sequence is inserted into the restriction site.

Cloning vector

Science.gov (United States)

Guilfoyle, R.A.; Smith, L.M.

1994-12-27

A vector comprising a filamentous phage sequence containing a first copy of filamentous phage gene X and other sequences necessary for the phage to propagate is disclosed. The vector also contains a second copy of filamentous phage gene X downstream from a promoter capable of promoting transcription in a bacterial host. In a preferred form of the present invention, the filamentous phage is M13 and the vector additionally includes a restriction endonuclease site located in such a manner as to substantially inactivate the second gene X when a DNA sequence is inserted into the restriction site. 2 figures.

Vector 33: A reduce program for vector algebra and calculus in orthogonal curvilinear coordinates

Science.gov (United States)

Harper, David

1989-06-01

This paper describes a package with enables REDUCE 3.3 to perform algebra and calculus operations upon vectors. Basic algebraic operations between vectors and between scalars and vectors are provided, including scalar (dot) product and vector (cross) product. The vector differential operators curl, divergence, gradient and Laplacian are also defined, and are valid in any orthogonal curvilinear coordinate system. The package is written in RLISP to allow algebra and calculus to be performed using notation identical to that for operations. Scalars and vectors can be mixed quite freely in the same expression. The package will be of interest to mathematicians, engineers and scientists who need to perform vector calculations in orthogonal curvilinear coordinates.

Suramin is a potent inhibitor of Chikungunya and Ebola virus cell entry.

Science.gov (United States)

Henß, Lisa; Beck, Simon; Weidner, Tatjana; Biedenkopf, Nadine; Sliva, Katja; Weber, Christopher; Becker, Stephan; Schnierle, Barbara S

2016-08-31

Chikungunya virus (CHIKV) is a mosquito-transmitted alphavirus that causes high fever, rash, and recurrent arthritis in humans. It has efficiently adapted to Aedes albopictus, which also inhabits temperate regions and currently causes large outbreaks in the Caribbean and Latin America. Ebola virus (EBOV) is a member of the filovirus family. It causes the Ebola virus disease (EDV), formerly known as Ebola hemorrhagic fever in humans and has a mortality rate of up to 70 %. The last outbreak in Western Africa was the largest in history and has caused approximately 25,000 cases and 10,000 deaths. For both viral infections no specific treatment or licensed vaccine is currently available. The bis-hexasulfonated naphthylurea, suramin, is used as a treatment for trypanosome-caused African river blindness. As a competitive inhibitor of heparin, suramin has been described to have anti-viral activity. We tested the activity of suramin during CHIKV or Ebola virus infection, using CHIKV and Ebola envelope glycoprotein pseudotyped lentiviral vectors and wild-type CHIKV and Ebola virus. Suramin efficiently inhibited CHIKV and Ebola envelope-mediated gene transfer while vesicular stomatitis virus G protein pseudotyped vectors were only marginally affected. In addition, suramin was able to inhibit wild-type CHIKV and Ebola virus replication in vitro. Inhibition occurred at early time points during CHIKV infection. Suramin, also known as Germanin or Bayer-205, is a market-authorized drug, however shows significant side effects, which probably prevents its use as a CHIKV drug, but due to the high lethality of Ebola virus infections, suramin might be valuable against Ebola infections.

Probing deformed orbitals with vector A( vector e, e' N)B reactions

International Nuclear Information System (INIS)

Garrido, E.; Caballero, J.A.; Moya de Guerra, E.; Sarriguren, P.; Udias, J.M.

1995-01-01

We present results for response functions and asymmetries in the nuclear reactions 37 vector Ar( vector e, e' n) 36 Ar and 37 vector K( vector e,e' p) 36 Ar at quasifree kinematics. We compare PWIA results obtained using deformed HF wave functions with PWIA and DWIA results obtained assuming a spherical mean field. We show that the complex structure of the deformed orbitals can be probed by coincidence measurements with polarized beam and targets. ((orig.))

Interferon-alpha subtype 11 activates NK cells and enables control of retroviral infection.

Directory of Open Access Journals (Sweden)

Kathrin Gibbert

Full Text Available The innate immune response mediated by cells such as natural killer (NK cells is critical for the rapid containment of virus replication and spread during acute infection. Here, we show that subtype 11 of the type I interferon (IFN family greatly potentiates the antiviral activity of NK cells during retroviral infection. Treatment of mice with IFN-α11 during Friend retrovirus infection (FV significantly reduced viral loads and resulted in long-term protection from virus-induced leukemia. The effect of IFN-α11 on NK cells was direct and signaled through the type I IFN receptor. Furthermore, IFN-α11-mediated activation of NK cells enabled cytolytic killing of FV-infected target cells via the exocytosis pathway. Depletion and adoptive transfer experiments illustrated that NK cells played a major role in successful IFN-α11 therapy. Additional experiments with Mouse Cytomegalovirus infections demonstrated that the therapeutic effect of IFN-α11 is not restricted to retroviruses. The type I IFN subtypes 2 and 5, which bind the same receptor as IFN-α11, did not elicit similar antiviral effects. These results demonstrate a unique and subtype-specific activation of NK cells by IFN-α11.

Multi-perspective views of students’ difficulties with one-dimensional vector and two-dimensional vector

Science.gov (United States)

Fauzi, Ahmad; Ratna Kawuri, Kunthi; Pratiwi, Retno

2017-01-01

Researchers of students’ conceptual change usually collects data from written tests and interviews. Moreover, reports of conceptual change often simply refer to changes in concepts, such as on a test, without any identification of the learning processes that have taken place. Research has shown that students have difficulties with vectors in university introductory physics courses and high school physics courses. In this study, we intended to explore students’ understanding of one-dimensional and two-dimensional vector in multi perspective views. In this research, we explore students’ understanding through test perspective and interviews perspective. Our research study adopted the mixed-methodology design. The participants of this research were sixty students of third semester of physics education department. The data of this research were collected by testand interviews. In this study, we divided the students’ understanding of one-dimensional vector and two-dimensional vector in two categories, namely vector skills of the addition of one-dimensionaland two-dimensional vector and the relation between vector skills and conceptual understanding. From the investigation, only 44% of students provided correct answer for vector skills of the addition of one-dimensional and two-dimensional vector and only 27% students provided correct answer for the relation between vector skills and conceptual understanding.

Custodial vector model

Science.gov (United States)

Becciolini, Diego; Franzosi, Diogo Buarque; Foadi, Roshan; Frandsen, Mads T.; Hapola, Tuomas; Sannino, Francesco

2015-07-01

We analyze the Large Hadron Collider (LHC) phenomenology of heavy vector resonances with a S U (2 )L×S U (2 )R spectral global symmetry. This symmetry partially protects the electroweak S parameter from large contributions of the vector resonances. The resulting custodial vector model spectrum and interactions with the standard model fields lead to distinct signatures at the LHC in the diboson, dilepton, and associated Higgs channels.

Vector Differential Calculus

OpenAIRE

HITZER, Eckhard MS

2002-01-01

This paper treats the fundamentals of the vector differential calculus part of universal geometric calculus. Geometric calculus simplifies and unifies the structure and notation of mathematics for all of science and engineering, and for technological applications. In order to make the treatment self-contained, I first compile all important geometric algebra relationships,which are necesssary for vector differential calculus. Then differentiation by vectors is introduced and a host of major ve...

Vectorization, parallelization and porting of nuclear codes. Vectorization and parallelization. Progress report fiscal 1999

Energy Technology Data Exchange (ETDEWEB)

Adachi, Masaaki; Ogasawara, Shinobu; Kume, Etsuo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Ishizuki, Shigeru; Nemoto, Toshiyuki; Kawasaki, Nobuo; Kawai, Wataru [Fujitsu Ltd., Tokyo (Japan); Yatake, Yo-ichi [Hitachi Ltd., Tokyo (Japan)

2001-02-01

Several computer codes in the nuclear field have been vectorized, parallelized and trans-ported on the FUJITSU VPP500 system, the AP3000 system, the SX-4 system and the Paragon system at Center for Promotion of Computational Science and Engineering in Japan Atomic Energy Research Institute. We dealt with 18 codes in fiscal 1999. These results are reported in 3 parts, i.e., the vectorization and the parallelization part on vector processors, the parallelization part on scalar processors and the porting part. In this report, we describe the vectorization and parallelization on vector processors. In this vectorization and parallelization on vector processors part, the vectorization of Relativistic Molecular Orbital Calculation code RSCAT, a microscopic transport code for high energy nuclear collisions code JAM, three-dimensional non-steady thermal-fluid analysis code STREAM, Relativistic Density Functional Theory code RDFT and High Speed Three-Dimensional Nodal Diffusion code MOSRA-Light on the VPP500 system and the SX-4 system are described. (author)

Elliptic-symmetry vector optical fields.

Science.gov (United States)

Pan, Yue; Li, Yongnan; Li, Si-Min; Ren, Zhi-Cheng; Kong, Ling-Jun; Tu, Chenghou; Wang, Hui-Tian

2014-08-11

We present in principle and demonstrate experimentally a new kind of vector fields: elliptic-symmetry vector optical fields. This is a significant development in vector fields, as this breaks the cylindrical symmetry and enriches the family of vector fields. Due to the presence of an additional degrees of freedom, which is the interval between the foci in the elliptic coordinate system, the elliptic-symmetry vector fields are more flexible than the cylindrical vector fields for controlling the spatial structure of polarization and for engineering the focusing fields. The elliptic-symmetry vector fields can find many specific applications from optical trapping to optical machining and so on.

Chikungunya Virus–Vector Interactions

Directory of Open Access Journals (Sweden)

Lark L. Coffey

2014-11-01

Full Text Available Chikungunya virus (CHIKV is a mosquito-borne alphavirus that causes chikungunya fever, a severe, debilitating disease that often produces chronic arthralgia. Since 2004, CHIKV has emerged in Africa, Indian Ocean islands, Asia, Europe, and the Americas, causing millions of human infections. Central to understanding CHIKV emergence is knowledge of the natural ecology of transmission and vector infection dynamics. This review presents current understanding of CHIKV infection dynamics in mosquito vectors and its relationship to human disease emergence. The following topics are reviewed: CHIKV infection and vector life history traits including transmission cycles, genetic origins, distribution, emergence and spread, dispersal, vector competence, vector immunity and microbial interactions, and co-infection by CHIKV and other arboviruses. The genetics of vector susceptibility and host range changes, population heterogeneity and selection for the fittest viral genomes, dual host cycling and its impact on CHIKV adaptation, viral bottlenecks and intrahost diversity, and adaptive constraints on CHIKV evolution are also discussed. The potential for CHIKV re-emergence and expansion into new areas and prospects for prevention via vector control are also briefly reviewed.

Extended vector-tensor theories

Energy Technology Data Exchange (ETDEWEB)

Kimura, Rampei; Naruko, Atsushi; Yoshida, Daisuke, E-mail: rampei@th.phys.titech.ac.jp, E-mail: naruko@th.phys.titech.ac.jp, E-mail: yoshida@th.phys.titech.ac.jp [Department of Physics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551 (Japan)

2017-01-01

Recently, several extensions of massive vector theory in curved space-time have been proposed in many literatures. In this paper, we consider the most general vector-tensor theories that contain up to two derivatives with respect to metric and vector field. By imposing a degeneracy condition of the Lagrangian in the context of ADM decomposition of space-time to eliminate an unwanted mode, we construct a new class of massive vector theories where five degrees of freedom can propagate, corresponding to three for massive vector modes and two for massless tensor modes. We find that the generalized Proca and the beyond generalized Proca theories up to the quartic Lagrangian, which should be included in this formulation, are degenerate theories even in curved space-time. Finally, introducing new metric and vector field transformations, we investigate the properties of thus obtained theories under such transformations.

Hyperbolic-symmetry vector fields.

Science.gov (United States)

Gao, Xu-Zhen; Pan, Yue; Cai, Meng-Qiang; Li, Yongnan; Tu, Chenghou; Wang, Hui-Tian

2015-12-14

We present and construct a new kind of orthogonal coordinate system, hyperbolic coordinate system. We present and design a new kind of local linearly polarized vector fields, which is defined as the hyperbolic-symmetry vector fields because the points with the same polarization form a series of hyperbolae. We experimentally demonstrate the generation of such a kind of hyperbolic-symmetry vector optical fields. In particular, we also study the modified hyperbolic-symmetry vector optical fields with the twofold and fourfold symmetric states of polarization when introducing the mirror symmetry. The tight focusing behaviors of these vector fields are also investigated. In addition, we also fabricate micro-structures on the K9 glass surfaces by several tightly focused (modified) hyperbolic-symmetry vector fields patterns, which demonstrate that the simulated tightly focused fields are in good agreement with the fabricated micro-structures.

Supergravity inspired vector curvaton

International Nuclear Information System (INIS)

Dimopoulos, Konstantinos

2007-01-01

It is investigated whether a massive Abelian vector field, whose gauge kinetic function is growing during inflation, can be responsible for the generation of the curvature perturbation in the Universe. Particle production is studied and it is shown that the vector field can obtain a scale-invariant superhorizon spectrum of perturbations with a reasonable choice of kinetic function. After inflation the vector field begins coherent oscillations, during which it corresponds to pressureless isotropic matter. When the vector field dominates the Universe, its perturbations give rise to the observed curvature perturbation following the curvaton scenario. It is found that this is possible if, after the end of inflation, the mass of the vector field increases at a phase transition at temperature of order 1 TeV or lower. Inhomogeneous reheating, whereby the vector field modulates the decay rate of the inflaton, is also studied

Constraining vectors and axial-vectors in walking technicolour by a holographic principle

DEFF Research Database (Denmark)

D. Dietrich, Dennis; Kouvaris, Christoforos

2008-01-01

We use a holographic principle to study the low-energy spectrum of walking technicolour models. In particular, we predict the masses of the axial vectors as well as the decay constants of vectors and axial vectors as functions of the mass of the techni-rho. Given that there are very few...

Recommendation on vectors and vector-transmitted diseases

OpenAIRE

Netherlands Food and Consumer Product Safety Authority

2009-01-01

In view of their increasing risk of introduction and their possible implications in causing major disease outbreaks, vectors, as well as vector-transmitted diseases like dengue, West Nile disease, Lyme disease and bluetongue need to be recognised as a threat to public and animal health and to the economy, also in the Netherlands. There has been an increase in the incidence of these diseases in the past two to three decades. Climate changes and changes in the use of land, water managemen...

Gauge anomaly with vector and axial-vector fields in 6D curved space

Science.gov (United States)

Yajima, Satoshi; Eguchi, Kohei; Fukuda, Makoto; Oka, Tomonori

2018-03-01

Imposing the conservation equation of the vector current for a fermion of spin 1/2 at the quantum level, a gauge anomaly for the fermion coupling with non-Abelian vector and axial-vector fields in 6D curved space is expressed in tensorial form. The anomaly consists of terms that resemble the chiral U(1) anomaly and the commutator terms that disappear if the axial-vector field is Abelian.

Vector manifestation and violation of vector dominance in hot matter

International Nuclear Information System (INIS)

Harada, Masayasu; Sasaki, Chihiro

2004-01-01

We show the details of the calculation of the hadronic thermal corrections to the two-point functions in the effective field theory of QCD for pions and vector mesons based on the hidden local symmetry (HLS) in hot matter using the background field gauge. We study the temperature dependence of the pion velocity in the low-temperature region determined from the hadronic thermal corrections, and show that, due to the presence of the dynamical vector meson, the pion velocity is smaller than the speed of the light already at one-loop level, in contrast to the result obtained in the ordinary chiral perturbation theory including only the pion at one-loop. Including the intrinsic temperature dependences of the parameters of the HLS Lagrangian determined from the underlying QCD through the Wilsonian matching, we show how the vector manifestation (VM), in which the massless vector meson becomes the chiral partner of pion, is realized at the critical temperature. We present a new prediction of the VM on the direct photon-π-π coupling which measures the validity of the vector dominance (VD) of the electromagnetic form factor of the pion: we find that the VD is largely violated at the critical temperature, which indicates that the assumption of the VD made in several analyses on the dilepton spectra in hot matter may need to be weakened for consistently including the effect of the dropping mass of the vector meson

Heavy Scalar, Vector, and Axial-Vector Mesons in Hot and Dense Nuclear Medium

Directory of Open Access Journals (Sweden)

Arvind Kumar

2014-01-01

Full Text Available In this work we shall investigate the mass modifications of scalar mesons (D0; B0, vector mesons (D*; B*, and axial-vector mesons (D1; B1 at finite density and temperature of the nuclear medium. The above mesons are modified in the nuclear medium through the modification of quark and gluon condensates. We will find the medium modification of quark and gluon condensates within chiral SU(3 model through the medium modification of scalar-isoscalar fields σ and ζ at finite density and temperature. These medium modified quark and gluon condensates will further be used through QCD sum rules for the evaluation of in-medium properties of the above mentioned scalar, vector, and axial vector mesons. We will also discuss the effects of density and temperature of the nuclear medium on the scattering lengths of the above scalar, vector, and axial-vector mesons. The study of the medium modifications of the above mesons may be helpful for understanding their production rates in heavy-ion collision experiments. The results of present investigations of medium modifications of scalar, vector, and axial-vector mesons at finite density and temperature can be verified in the compressed baryonic matter (CBM experiment of FAIR facility at GSI, Germany.

Vector Fields on Product Manifolds

OpenAIRE

Kurz, Stefan

2011-01-01

This short report establishes some basic properties of smooth vector fields on product manifolds. The main results are: (i) On a product manifold there always exists a direct sum decomposition into horizontal and vertical vector fields. (ii) Horizontal and vertical vector fields are naturally isomorphic to smooth families of vector fields defined on the factors. Vector fields are regarded as derivations of the algebra of smooth functions.

Light scattering of rectangular slot antennas: parallel magnetic vector vs perpendicular electric vector

Science.gov (United States)

Lee, Dukhyung; Kim, Dai-Sik

2016-01-01

We study light scattering off rectangular slot nano antennas on a metal film varying incident polarization and incident angle, to examine which field vector of light is more important: electric vector perpendicular to, versus magnetic vector parallel to the long axis of the rectangle. While vector Babinet’s principle would prefer magnetic field along the long axis for optimizing slot antenna function, convention and intuition most often refer to the electric field perpendicular to it. Here, we demonstrate experimentally that in accordance with vector Babinet’s principle, the incident magnetic vector parallel to the long axis is the dominant component, with the perpendicular incident electric field making a small contribution of the factor of 1/|ε|, the reciprocal of the absolute value of the dielectric constant of the metal, owing to the non-perfectness of metals at optical frequencies.

Generalization of concurrence vectors

International Nuclear Information System (INIS)

Yu Changshui; Song Heshan

2004-01-01

In this Letter, based on the generalization of concurrence vectors for bipartite pure state with respect to employing tensor product of generators of the corresponding rotation groups, we generalize concurrence vectors to the case of mixed states; a new criterion of separability of multipartite pure states is given out, for which we define a concurrence vector; we generalize the vector to the case of multipartite mixed state and give out a good measure of free entanglement

Vector Network Coding Algorithms

OpenAIRE

Ebrahimi, Javad; Fragouli, Christina

2010-01-01

We develop new algebraic algorithms for scalar and vector network coding. In vector network coding, the source multicasts information by transmitting vectors of length L, while intermediate nodes process and combine their incoming packets by multiplying them with L x L coding matrices that play a similar role as coding c in scalar coding. Our algorithms for scalar network jointly optimize the employed field size while selecting the coding coefficients. Similarly, for vector coding, our algori...

Complex Polynomial Vector Fields

DEFF Research Database (Denmark)

Dias, Kealey

vector fields. Since the class of complex polynomial vector fields in the plane is natural to consider, it is remarkable that its study has only begun very recently. There are numerous fundamental questions that are still open, both in the general classification of these vector fields, the decomposition...... of parameter spaces into structurally stable domains, and a description of the bifurcations. For this reason, the talk will focus on these questions for complex polynomial vector fields.......The two branches of dynamical systems, continuous and discrete, correspond to the study of differential equations (vector fields) and iteration of mappings respectively. In holomorphic dynamics, the systems studied are restricted to those described by holomorphic (complex analytic) functions...

Validation of SplitVectors Encoding for Quantitative Visualization of Large-Magnitude-Range Vector Fields.

Science.gov (United States)

Henan Zhao; Bryant, Garnett W; Griffin, Wesley; Terrill, Judith E; Jian Chen

2017-06-01

We designed and evaluated SplitVectors, a new vector field display approach to help scientists perform new discrimination tasks on large-magnitude-range scientific data shown in three-dimensional (3D) visualization environments. SplitVectors uses scientific notation to display vector magnitude, thus improving legibility. We present an empirical study comparing the SplitVectors approach with three other approaches - direct linear representation, logarithmic, and text display commonly used in scientific visualizations. Twenty participants performed three domain analysis tasks: reading numerical values (a discrimination task), finding the ratio between values (a discrimination task), and finding the larger of two vectors (a pattern detection task). Participants used both mono and stereo conditions. Our results suggest the following: (1) SplitVectors improve accuracy by about 10 times compared to linear mapping and by four times to logarithmic in discrimination tasks; (2) SplitVectors have no significant differences from the textual display approach, but reduce cluttering in the scene; (3) SplitVectors and textual display are less sensitive to data scale than linear and logarithmic approaches; (4) using logarithmic can be problematic as participants' confidence was as high as directly reading from the textual display, but their accuracy was poor; and (5) Stereoscopy improved performance, especially in more challenging discrimination tasks.

Vectorization, parallelization and porting of nuclear codes (vectorization and parallelization). Progress report fiscal 1998

International Nuclear Information System (INIS)

Ishizuki, Shigeru; Kawai, Wataru; Nemoto, Toshiyuki; Ogasawara, Shinobu; Kume, Etsuo; Adachi, Masaaki; Kawasaki, Nobuo; Yatake, Yo-ichi

2000-03-01

Several computer codes in the nuclear field have been vectorized, parallelized and transported on the FUJITSU VPP500 system, the AP3000 system and the Paragon system at Center for Promotion of Computational Science and Engineering in Japan Atomic Energy Research Institute. We dealt with 12 codes in fiscal 1998. These results are reported in 3 parts, i.e., the vectorization and parallelization on vector processors part, the parallelization on scalar processors part and the porting part. In this report, we describe the vectorization and parallelization on vector processors. In this vectorization and parallelization on vector processors part, the vectorization of General Tokamak Circuit Simulation Program code GTCSP, the vectorization and parallelization of Molecular Dynamics NTV (n-particle, Temperature and Velocity) Simulation code MSP2, Eddy Current Analysis code EDDYCAL, Thermal Analysis Code for Test of Passive Cooling System by HENDEL T2 code THANPACST2 and MHD Equilibrium code SELENEJ on the VPP500 are described. In the parallelization on scalar processors part, the parallelization of Monte Carlo N-Particle Transport code MCNP4B2, Plasma Hydrodynamics code using Cubic Interpolated Propagation Method PHCIP and Vectorized Monte Carlo code (continuous energy model / multi-group model) MVP/GMVP on the Paragon are described. In the porting part, the porting of Monte Carlo N-Particle Transport code MCNP4B2 and Reactor Safety Analysis code RELAP5 on the AP3000 are described. (author)

Ultrasound Backscatter Microscopy Image-Guided Intraventricular Gene Delivery at Murine Embryonic Age 9.5 and 10.5 Produces Distinct Transgene Expression Patterns at the Adult Stage

Directory of Open Access Journals (Sweden)

Jiwon Jang

2013-11-01

Full Text Available In utero injection of a retroviral vector into the embryonic telencephalon aided by ultrasound backscatter microscopy permits introduction of a gene of interest at an early stage of development. In this study, we compared the tissue distribution of gene expression in adult mice injected with retroviral vectors at different embryonic ages in utero. Following ultrasound image-guided gene delivery (UIGD into the embryonic telencephalon, adult mice were subjected to whole-body luciferase imaging and immunohistochemical analysis at 6 weeks and 1 year postinjection. Luciferase activity was observed in a wide range of tissues in animals injected at embryonic age 9.5 (E9.5, whereas animals injected at E10.5 showed brain-localized reporter gene expression. These results suggest that mouse embryonic brain creates a closed and impermeable structure around E10. Therefore, by injecting a transgene before or after E10, transgene expression can be manipulated to be local or systemic. Our results also provide information that widens the applicability of UIGD beyond neuroscience studies.

Equivalent Vectors

Science.gov (United States)

Levine, Robert

2004-01-01

The cross-product is a mathematical operation that is performed between two 3-dimensional vectors. The result is a vector that is orthogonal or perpendicular to both of them. Learning about this for the first time while taking Calculus-III, the class was taught that if AxB = AxC, it does not necessarily follow that B = C. This seemed baffling. The…

Speculative dynamic vectorization to assist static vectorization in a HW/SW co-designed environment

OpenAIRE

Kumar, R.; Martinez, A.; Gonzalez, A.

2013-01-01

Compiler based static vectorization is used widely to extract data level parallelism from computation intensive applications. Static vectorization is very effective in vectorizing traditional array based applications. However, compilers inability to reorder ambiguous memory references severely limits vectorization opportunities, especially in pointer rich applications. HW/SW co-designed processors provide an excellent opportunity to optimize the applications at runtime. The availability of dy...

Vectorization at the KENO-IV code

International Nuclear Information System (INIS)

Asai, K.; Higuchi, K.; Katakura, J.

1986-01-01

The multigroup criticality safety code KENO-IV has been vectorized and tested on the FACOM VP-100 vector processor. At first, the vectorized KENO-IV on a scalar processor was slower than the original one by a factor of 1.4 because of the overhead introduced by vectorization. Making modifications of algorithms and techniques for vectorization, the vectorized version has become faster than the original one by a factor of 1.4 on the vector processor. For further speedup of the code, some improvements on compiler and hardware, especially on addition of Monte Carlo pipelines to the vector processor, are discussed

Reciprocity relationships in vector acoustics and their application to vector field calculations.

Science.gov (United States)

Deal, Thomas J; Smith, Kevin B

2017-08-01

The reciprocity equation commonly stated in underwater acoustics relates pressure fields and monopole sources. It is often used to predict the pressure measured by a hydrophone for multiple source locations by placing a source at the hydrophone location and calculating the field everywhere for that source. A similar equation that governs the orthogonal components of the particle velocity field is needed to enable this computational method to be used for acoustic vector sensors. This paper derives a general reciprocity equation that accounts for both monopole and dipole sources. This vector-scalar reciprocity equation can be used to calculate individual components of the received vector field by altering the source type used in the propagation calculation. This enables a propagation model to calculate the received vector field components for an arbitrary number of source locations with a single model run for each vector field component instead of requiring one model run for each source location. Application of the vector-scalar reciprocity principle is demonstrated with analytic solutions for a range-independent environment and with numerical solutions for a range-dependent environment using a parabolic equation model.

Vectors and their applications

CERN Document Server

Pettofrezzo, Anthony J

2005-01-01

Geared toward undergraduate students, this text illustrates the use of vectors as a mathematical tool in plane synthetic geometry, plane and spherical trigonometry, and analytic geometry of two- and three-dimensional space. Its rigorous development includes a complete treatment of the algebra of vectors in the first two chapters.Among the text's outstanding features are numbered definitions and theorems in the development of vector algebra, which appear in italics for easy reference. Most of the theorems include proofs, and coordinate position vectors receive an in-depth treatment. Key concept

Convexity and Marginal Vectors

NARCIS (Netherlands)

van Velzen, S.; Hamers, H.J.M.; Norde, H.W.

2002-01-01

In this paper we construct sets of marginal vectors of a TU game with the property that if the marginal vectors from these sets are core elements, then the game is convex.This approach leads to new upperbounds on the number of marginal vectors needed to characterize convexity.An other result is that

Gene therapy/bone marrow transplantation in ADA-deficient mice: roles of enzyme-replacement therapy and cytoreduction

Science.gov (United States)

Jin, Xiangyang; Wang, Xingchao; Yu, Xiao-Jin; Rozengurt, Nora; Kaufman, Michael L.; Wang, Xiaoyan; Gjertson, David; Zhou, Yang; Blackburn, Michael R.; Kohn, Donald B.

2012-01-01

Gene therapy (GT) for adenosine deaminase–deficient severe combined immune deficiency (ADA-SCID) can provide significant long-term benefit when patients are given nonmyeloablative conditioning and ADA enzyme-replacement therapy (ERT) is withheld before autologous transplantation of γ-retroviral vector-transduced BM CD34+ cells. To determine the contributions of conditioning and discontinuation of ERT to the therapeutic effects, we analyzed these factors in Ada gene knockout mice (Ada−/−). Mice were transplanted with ADA-deficient marrow transduced with an ADA-expressing γ-retroviral vector without preconditioning or after 200 cGy or 900 cGy total-body irradiation and evaluated after 4 months. In all tissues analyzed, vector copy numbers (VCNs) were 100- to 1000-fold greater in mice receiving 900 cGy compared with 200 cGy (P < .05). In mice receiving 200 cGy, VCN was similar whether ERT was stopped or given for 1 or 4 months after GT. In unconditioned mice, there was decreased survival with and without ERT, and VCN was very low to undetectable. When recipients were conditioned with 200 cGy and received transduced lineage-depleted marrow, only recipients receiving ERT (1 or 4 months) had detectable vector sequences in thymocytes. In conclusion, cytoreduction is important for the engraftment of gene-transduced HSC, and short-term ERT after GT did not diminish the capacity of gene-corrected cells to engraft and persist. PMID:22833548

Integrating Transgenic Vector Manipulation with Clinical Interventions to Manage Vector-Borne Diseases.

Directory of Open Access Journals (Sweden)

Kenichi W Okamoto

2016-03-01

Full Text Available Many vector-borne diseases lack effective vaccines and medications, and the limitations of traditional vector control have inspired novel approaches based on using genetic engineering to manipulate vector populations and thereby reduce transmission. Yet both the short- and long-term epidemiological effects of these transgenic strategies are highly uncertain. If neither vaccines, medications, nor transgenic strategies can by themselves suffice for managing vector-borne diseases, integrating these approaches becomes key. Here we develop a framework to evaluate how clinical interventions (i.e., vaccination and medication can be integrated with transgenic vector manipulation strategies to prevent disease invasion and reduce disease incidence. We show that the ability of clinical interventions to accelerate disease suppression can depend on the nature of the transgenic manipulation deployed (e.g., whether vector population reduction or replacement is attempted. We find that making a specific, individual strategy highly effective may not be necessary for attaining public-health objectives, provided suitable combinations can be adopted. However, we show how combining only partially effective antimicrobial drugs or vaccination with transgenic vector manipulations that merely temporarily lower vector competence can amplify disease resurgence following transient suppression. Thus, transgenic vector manipulation that cannot be sustained can have adverse consequences-consequences which ineffective clinical interventions can at best only mitigate, and at worst temporarily exacerbate. This result, which arises from differences between the time scale on which the interventions affect disease dynamics and the time scale of host population dynamics, highlights the importance of accounting for the potential delay in the effects of deploying public health strategies on long-term disease incidence. We find that for systems at the disease-endemic equilibrium, even

Complex Polynomial Vector Fields

DEFF Research Database (Denmark)

The two branches of dynamical systems, continuous and discrete, correspond to the study of differential equations (vector fields) and iteration of mappings respectively. In holomorphic dynamics, the systems studied are restricted to those described by holomorphic (complex analytic) functions...... or meromorphic (allowing poles as singularities) functions. There already exists a well-developed theory for iterative holomorphic dynamical systems, and successful relations found between iteration theory and flows of vector fields have been one of the main motivations for the recent interest in holomorphic...... vector fields. Since the class of complex polynomial vector fields in the plane is natural to consider, it is remarkable that its study has only begun very recently. There are numerous fundamental questions that are still open, both in the general classification of these vector fields, the decomposition...

Vector financial rogue waves

International Nuclear Information System (INIS)

Yan, Zhenya

2011-01-01

The coupled nonlinear volatility and option pricing model presented recently by Ivancevic is investigated, which generates a leverage effect, i.e., stock volatility is (negatively) correlated to stock returns, and can be regarded as a coupled nonlinear wave alternative of the Black–Scholes option pricing model. In this Letter, we analytically propose vector financial rogue waves of the coupled nonlinear volatility and option pricing model without an embedded w-learning. Moreover, we exhibit their dynamical behaviors for chosen different parameters. The vector financial rogue wave (rogon) solutions may be used to describe the possible physical mechanisms for the rogue wave phenomena and to further excite the possibility of relative researches and potential applications of vector rogue waves in the financial markets and other related fields. -- Highlights: ► We investigate the coupled nonlinear volatility and option pricing model. ► We analytically present vector financial rogue waves. ► The vector financial rogue waves may be used to describe the extreme events in financial markets. ► This results may excite the relative researches and potential applications of vector rogue waves.

Video Vectorization via Tetrahedral Remeshing.

Science.gov (United States)

Wang, Chuan; Zhu, Jie; Guo, Yanwen; Wang, Wenping

2017-02-09

We present a video vectorization method that generates a video in vector representation from an input video in raster representation. A vector-based video representation offers the benefits of vector graphics, such as compactness and scalability. The vector video we generate is represented by a simplified tetrahedral control mesh over the spatial-temporal video volume, with color attributes defined at the mesh vertices. We present novel techniques for simplification and subdivision of a tetrahedral mesh to achieve high simplification ratio while preserving features and ensuring color fidelity. From an input raster video, our method is capable of generating a compact video in vector representation that allows a faithful reconstruction with low reconstruction errors.

Risk factors for death in HIV-infected adult African patients receiving anti-retroviral therapy.

Science.gov (United States)

Siika, A M; Wools-Kaloustian, K; Mwangi, A W; Kimaiyo, S N; Diero, L O; Ayuo, P O; Owino-Ong'or, W D; Sidle, J E; Einterz, R M; Yiannoutsos, C T; Musick, B; Tierney, W M

2010-11-01

To determine risk factors for death in HIV-infected African patients on anti-retroviral therapy (ART). Retrospective Case-control study. The MOH-USAID-AMPATH Partnership ambulatory HIV-care clinics in western Kenya. Between November 2001 and December 2005 demographic, clinical and laboratory data from 527 deceased and 1054 living patients receiving ART were compared to determine independent risk factors for death. Median age at ART initiation was 38 versus 36 years for the deceased and living patients respectively (p100/mm3 (HR=1.553. 95% CI (1.156, 2.087), p<0.003). Patients attending rural clinics had threefold higher risk of dying compared to patients attending clinic at a tertiary referral hospital (p<0.0001). Two years after initiating treatment fifty percent of non-adherent patients were alive compared to 75% of adherent patients. Male gender, WHO Stage and haemoglobin level <10 grams% were associated with time to death while age, marital status, educational level, employment status and weight were not. Profoundly immunosuppressed patients were more likely to die early in the course of treatment. Also, patients receiving care in rural clinics were at greater risk of dying than those receiving care in the tertiary referral hospital.

Boosting of HIV-1 neutralizing antibody responses by a distally related retroviral envelope protein.

Science.gov (United States)

Uchtenhagen, Hannes; Schiffner, Torben; Bowles, Emma; Heyndrickx, Leo; LaBranche, Celia; Applequist, Steven E; Jansson, Marianne; De Silva, Thushan; Back, Jaap Willem; Achour, Adnane; Scarlatti, Gabriella; Fomsgaard, Anders; Montefiori, David; Stewart-Jones, Guillaume; Spetz, Anna-Lena

2014-06-15

Our knowledge of the binding sites for neutralizing Abs (NAb) that recognize a broad range of HIV-1 strains (bNAb) has substantially increased in recent years. However, gaps remain in our understanding of how to focus B cell responses to vulnerable conserved sites within the HIV-1 envelope glycoprotein (Env). In this article, we report an immunization strategy composed of a trivalent HIV-1 (clade B envs) DNA prime, followed by a SIVmac239 gp140 Env protein boost that aimed to focus the immune response to structurally conserved parts of the HIV-1 and simian immunodeficiency virus (SIV) Envs. Heterologous NAb titers, primarily to tier 1 HIV-1 isolates, elicited during the trivalent HIV-1 env prime, were significantly increased by the SIVmac239 gp140 protein boost in rabbits. Epitope mapping of Ab-binding reactivity revealed preferential recognition of the C1, C2, V2, V3, and V5 regions. These results provide a proof of concept that a distally related retroviral SIV Env protein boost can increase pre-existing NAb responses against HIV-1. Copyright © 2014 by The American Association of Immunologists, Inc.

Selection vector filter framework

Science.gov (United States)

Lukac, Rastislav; Plataniotis, Konstantinos N.; Smolka, Bogdan; Venetsanopoulos, Anastasios N.

2003-10-01

We provide a unified framework of nonlinear vector techniques outputting the lowest ranked vector. The proposed framework constitutes a generalized filter class for multichannel signal processing. A new class of nonlinear selection filters are based on the robust order-statistic theory and the minimization of the weighted distance function to other input samples. The proposed method can be designed to perform a variety of filtering operations including previously developed filtering techniques such as vector median, basic vector directional filter, directional distance filter, weighted vector median filters and weighted directional filters. A wide range of filtering operations is guaranteed by the filter structure with two independent weight vectors for angular and distance domains of the vector space. In order to adapt the filter parameters to varying signal and noise statistics, we provide also the generalized optimization algorithms taking the advantage of the weighted median filters and the relationship between standard median filter and vector median filter. Thus, we can deal with both statistical and deterministic aspects of the filter design process. It will be shown that the proposed method holds the required properties such as the capability of modelling the underlying system in the application at hand, the robustness with respect to errors in the model of underlying system, the availability of the training procedure and finally, the simplicity of filter representation, analysis, design and implementation. Simulation studies also indicate that the new filters are computationally attractive and have excellent performance in environments corrupted by bit errors and impulsive noise.

Symbolic computer vector analysis

Science.gov (United States)

Stoutemyer, D. R.

1977-01-01

A MACSYMA program is described which performs symbolic vector algebra and vector calculus. The program can combine and simplify symbolic expressions including dot products and cross products, together with the gradient, divergence, curl, and Laplacian operators. The distribution of these operators over sums or products is under user control, as are various other expansions, including expansion into components in any specific orthogonal coordinate system. There is also a capability for deriving the scalar or vector potential of a vector field. Examples include derivation of the partial differential equations describing fluid flow and magnetohydrodynamics, for 12 different classic orthogonal curvilinear coordinate systems.

Vector continued fractions using a generalized inverse

International Nuclear Information System (INIS)

Haydock, Roger; Nex, C M M; Wexler, Geoffrey

2004-01-01

A real vector space combined with an inverse (involution) for vectors is sufficient to define a vector continued fraction whose parameters consist of vector shifts and changes of scale. The choice of sign for different components of the vector inverse permits construction of vector analogues of the Jacobi continued fraction. These vector Jacobi fractions are related to vector and scalar-valued polynomial functions of the vectors, which satisfy recurrence relations similar to those of orthogonal polynomials. The vector Jacobi fraction has strong convergence properties which are demonstrated analytically, and illustrated numerically

The Cross Product of Two Vectors Is Not Just Another Vector--A Major Misconception Being Perpetuated in Calculus and Vector Analysis Textbooks.

Science.gov (United States)

Elk, Seymour B.

1997-01-01

Suggests that the cross product of two vectors can be more easily and accurately explained by starting from the perspective of dyadics because then the concept of vector multiplication has a simple geometrical picture that encompasses both the dot and cross products in any number of dimensions in terms of orthogonal unit vector components. (AIM)

Major vectors and vector-borne diseases in small ruminants in Ethiopia: A systematic review.

Science.gov (United States)

Asmare, Kassahun; Abayneh, Takele; Sibhat, Berhanu; Shiferaw, Dessie; Szonyi, Barbara; Krontveit, Randi I; Skjerve, Eystein; Wieland, Barbara

2017-06-01

Vector-borne diseases are among major health constraints of small ruminant in Ethiopia. While various studies on single vector-borne diseases or presence of vectors have been conducted, no summarized evidence is available on the occurrence of these diseases and the related vectors. This systematic literature review provides a comprehensive summary on major vectors and vector-borne diseases in small ruminants in Ethiopia. Search for published and unpublished literature was conducted between 8th of January and 25th of June 2015. The search was both manual and electronic. The databases used in electronic search were PubMed, Web of Science, CAB Direct and AJOL. For most of the vector-borne diseases, the summary was limited to narrative synthesis due to lack of sufficient data. Meta-analysis was computed for trypanosomosis and dermatophilosis while meta-regression and sensitivity analysis was done only for trypanososmosis due to lack of sufficient reports on dermatophilosis. Owing emphasis to their vector role, ticks and flies were summarized narratively at genera/species level. In line with inclusion criteria, out of 106 initially identified research reports 43 peer-reviewed articles passed the quality assessment. Data on 7 vector-borne diseases were extracted at species and region level from each source. Accordingly, the pooled prevalence estimate of trypanosomosis was 3.7% with 95% confidence interval (CI) 2.8, 4.9), while that of dermatophilosis was 3.1% (95% CI: 1.6, 6.0). The in-between study variance noted for trypanosomosis was statistically significant (pparasitic presence in blood was documented for babesiosis (3.7% in goats); and anaplasmosis (3.9% in sheep). Serological evidence was retrieved for bluetongue ranging from 34.1% to 46.67% in sheep, and coxiellosis was 10.4% in goats. There was also molecular evidence on the presence of theileriosis in sheep (93%, n=160) and goats (1.9%, n=265). Regarding vectors of veterinary importance, 14 species of ticks in

GPU Accelerated Vector Median Filter

Science.gov (United States)

Aras, Rifat; Shen, Yuzhong

2011-01-01

Noise reduction is an important step for most image processing tasks. For three channel color images, a widely used technique is vector median filter in which color values of pixels are treated as 3-component vectors. Vector median filters are computationally expensive; for a window size of n x n, each of the n(sup 2) vectors has to be compared with other n(sup 2) - 1 vectors in distances. General purpose computation on graphics processing units (GPUs) is the paradigm of utilizing high-performance many-core GPU architectures for computation tasks that are normally handled by CPUs. In this work. NVIDIA's Compute Unified Device Architecture (CUDA) paradigm is used to accelerate vector median filtering. which has to the best of our knowledge never been done before. The performance of GPU accelerated vector median filter is compared to that of the CPU and MPI-based versions for different image and window sizes, Initial findings of the study showed 100x improvement of performance of vector median filter implementation on GPUs over CPU implementations and further speed-up is expected after more extensive optimizations of the GPU algorithm .

An Optimized GD2-Targeting Retroviral Cassette for More Potent and Safer Cellular Therapy of Neuroblastoma and Other Cancers.

Directory of Open Access Journals (Sweden)

Simon Thomas

Full Text Available Neuroblastoma is the commonest extra cranial solid cancer of childhood. Despite escalation of treatment regimens, a significant minority of patients die of their disease. Disialoganglioside (GD2 is consistently expressed at high-levels in neuroblastoma tumors, which have been targeted with some success using therapeutic monoclonal antibodies. GD2 is also expressed in a range of other cancer but with the exception of some peripheral nerves is largely absent from non-transformed tissues. Chimeric Antigen Receptors (CARs are artificial type I proteins which graft the specificity of a monoclonal antibody onto a T-cell. Clinical data with early CAR designs directed against GD2 have shown some promise in Neuroblastoma. Here, we describe a GD2-targeting CAR retroviral cassette, which has been optimized for CAR T-cell persistence, efficacy and safety.

Effects of Climate and Climate Change on Vectors and Vector-Borne Diseases: Ticks Are Different.

Science.gov (United States)

Ogden, Nick H; Lindsay, L Robbin

2016-08-01

There has been considerable debate as to whether global risk from vector-borne diseases will be impacted by climate change. This has focussed on important mosquito-borne diseases that are transmitted by the vectors from infected to uninfected humans. However, this debate has mostly ignored the biological diversity of vectors and vector-borne diseases. Here, we review how climate and climate change may impact those most divergent of arthropod disease vector groups: multivoltine insects and hard-bodied (ixodid) ticks. We contrast features of the life cycles and behaviour of these arthropods, and how weather, climate, and climate change may have very different impacts on the spatiotemporal occurrence and abundance of vectors, and the pathogens they transmit. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

Hierarchal scalar and vector tetrahedra

International Nuclear Information System (INIS)

Webb, J.P.; Forghani, B.

1993-01-01

A new set of scalar and vector tetrahedral finite elements are presented. The elements are hierarchal, allowing mixing of polynomial orders; scalar orders up to 3 and vector orders up to 2 are defined. The vector elements impose tangential continuity on the field but not normal continuity, making them suitable for representing the vector electric or magnetic field. Further, the scalar and vector elements are such that they can easily be used in the same mesh, a requirement of many quasi-static formulations. Results are presented for two 50 Hz problems: the Bath Cube, and TEAM Problem 7

Receptor-Targeted Nipah Virus Glycoproteins Improve Cell-Type Selective Gene Delivery and Reveal a Preference for Membrane-Proximal Cell Attachment.

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Ruben R Bender

2016-06-01

Full Text Available Receptor-targeted lentiviral vectors (LVs can be an effective tool for selective transfer of genes into distinct cell types of choice. Moreover, they can be used to determine the molecular properties that cell surface proteins must fulfill to act as receptors for viral glycoproteins. Here we show that LVs pseudotyped with receptor-targeted Nipah virus (NiV glycoproteins effectively enter into cells when they use cell surface proteins as receptors that bring them closely enough to the cell membrane (less than 100 Å distance. Then, they were flexible in receptor usage as demonstrated by successful targeting of EpCAM, CD20, and CD8, and as selective as LVs pseudotyped with receptor-targeted measles virus (MV glycoproteins, the current standard for cell-type specific gene delivery. Remarkably, NiV-LVs could be produced at up to two orders of magnitude higher titers compared to their MV-based counterparts and were at least 10,000-fold less effectively neutralized than MV glycoprotein pseudotyped LVs by pooled human intravenous immunoglobulin. An important finding for NiV-LVs targeted to Her2/neu was an about 100-fold higher gene transfer activity when particles were targeted to membrane-proximal regions as compared to particles binding to a more membrane-distal epitope. Likewise, the low gene transfer activity mediated by NiV-LV particles bound to the membrane distal domains of CD117 or the glutamate receptor subunit 4 (GluA4 was substantially enhanced by reducing receptor size to below 100 Å. Overall, the data suggest that the NiV glycoproteins are optimally suited for cell-type specific gene delivery with LVs and, in addition, for the first time define which parts of a cell surface protein should be targeted to achieve optimal gene transfer rates with receptor-targeted LVs.

Generation of arbitrary vector fields based on a pair of orthogonal elliptically polarized base vectors.

Science.gov (United States)

Xu, Danfeng; Gu, Bing; Rui, Guanghao; Zhan, Qiwen; Cui, Yiping

2016-02-22

We present an arbitrary vector field with hybrid polarization based on the combination of a pair of orthogonal elliptically polarized base vectors on the Poincaré sphere. It is shown that the created vector field is only dependent on the latitude angle 2χ but is independent on the longitude angle 2ψ on the Poincaré sphere. By adjusting the latitude angle 2χ, which is related to two identical waveplates in a common path interferometric arrangement, one could obtain arbitrary type of vector fields. Experimentally, we demonstrate the generation of such kind of vector fields and confirm the distribution of state of polarization by the measurement of Stokes parameters. Besides, we investigate the tight focusing properties of these vector fields. It is found that the additional degree of freedom 2χ provided by arbitrary vector field with hybrid polarization allows one to control the spatial structure of polarization and to engineer the focusing field.

The upstream enhancer elements of the G6PC promoter are critical for optimal G6PC expression in murine glycogen storage disease type Ia.

Science.gov (United States)

Lee, Young Mok; Pan, Chi-Jiunn; Koeberl, Dwight D; Mansfield, Brian C; Chou, Janice Y

2013-11-01

Glycogen storage disease type-Ia (GSD-Ia) patients deficient in glucose-6-phosphatase-α (G6Pase-α or G6PC) manifest impaired glucose homeostasis characterized by fasting hypoglycemia, growth retardation, hepatomegaly, nephromegaly, hyperlipidemia, hyperuricemia, and lactic acidemia. Two efficacious recombinant adeno-associated virus pseudotype 2/8 (rAAV8) vectors expressing human G6Pase-α have been independently developed. One is a single-stranded vector containing a 2864-bp of the G6PC promoter/enhancer (rAAV8-GPE) and the other is a double-stranded vector containing a shorter 382-bp minimal G6PC promoter/enhancer (rAAV8-miGPE). To identify the best construct, a direct comparison of the rAAV8-GPE and the rAAV8-miGPE vectors was initiated to determine the best vector to take forward into clinical trials. We show that the rAAV8-GPE vector directed significantly higher levels of hepatic G6Pase-α expression, achieved greater reduction in hepatic glycogen accumulation, and led to a better toleration of fasting in GSD-Ia mice than the rAAV8-miGPE vector. Our results indicated that additional control elements in the rAAV8-GPE vector outweigh the gains from the double-stranded rAAV8-miGPE transduction efficiency, and that the rAAV8-GPE vector is the current choice for clinical translation in human GSD-Ia. © 2013.

Calculus with vectors

CERN Document Server

Treiman, Jay S

2014-01-01

Calculus with Vectors grew out of a strong need for a beginning calculus textbook for undergraduates who intend to pursue careers in STEM. fields. The approach introduces vector-valued functions from the start, emphasizing the connections between one-variable and multi-variable calculus. The text includes early vectors and early transcendentals and includes a rigorous but informal approach to vectors. Examples and focused applications are well presented along with an abundance of motivating exercises. All three-dimensional graphs have rotatable versions included as extra source materials and may be freely downloaded and manipulated with Maple Player; a free Maple Player App is available for the iPad on iTunes. The approaches taken to topics such as the derivation of the derivatives of sine and cosine, the approach to limits, and the use of "tables" of integration have been modified from the standards seen in other textbooks in order to maximize the ease with which students may comprehend the material. Additio...

Test of understanding of vectors: A reliable multiple-choice vector concept test

Science.gov (United States)

Barniol, Pablo; Zavala, Genaro

2014-06-01

In this article we discuss the findings of our research on students' understanding of vector concepts in problems without physical context. First, we develop a complete taxonomy of the most frequent errors made by university students when learning vector concepts. This study is based on the results of several test administrations of open-ended problems in which a total of 2067 students participated. Using this taxonomy, we then designed a 20-item multiple-choice test [Test of understanding of vectors (TUV)] and administered it in English to 423 students who were completing the required sequence of introductory physics courses at a large private Mexican university. We evaluated the test's content validity, reliability, and discriminatory power. The results indicate that the TUV is a reliable assessment tool. We also conducted a detailed analysis of the students' understanding of the vector concepts evaluated in the test. The TUV is included in the Supplemental Material as a resource for other researchers studying vector learning, as well as instructors teaching the material.

Perinatal genotoxicity and carcinogenicity of anti-retroviral nucleoside analog drugs

International Nuclear Information System (INIS)

Poirier, Miriam C.; Olivero, Ofelia A.; Walker, Dale M.; Walker, Vernon E.

2004-01-01

The current worldwide spread of the human immunodeficiency virus-1 (HIV-1) to the heterosexual population has resulted in approximately 800 000 children born yearly to HIV-1-infected mothers. In the absence of anti-retroviral intervention, about 25% of the approximately 7000 children born yearly to HIV-1-infected women in the United States are HIV-1 infected. Administration of zidovudine (AZT) prophylaxis during pregnancy reduces the rate of infant HIV-1 infection to approximately 7%, and further reductions are achieved with the addition of lamivudine (3TC) in the clinical formulation Combivir. Whereas clinically this is a remarkable achievement, AZT and 3TC are DNA replication chain terminators known to induce various types of genotoxicity. Studies in rodents have demonstrated AZT-DNA incorporation, HPRT mutagenesis, telomere shortening, and tumorigenicity in organs of fetal mice exposed transplacentally to AZT. In monkeys, both AZT and 3TC become incorporated into the DNA from multiple fetal organs taken at birth after administration of human-equivalent protocols to pregnant dams during gestation, and telomere shortening has been found in monkey fetuses exposed to both drugs. In human infants, AZT-DNA and 3TC-DNA incorporation as well as HPRT and GPA mutagenesis have been documented in cord blood from infants exposed in utero to Combivir. In infants of mice, monkeys, and humans, levels of AZT-DNA incorporation were remarkably similar, and in newborn mice and humans, mutation frequencies were also very similar. Given the risk-benefit ratio, these highly successful drugs will continue to be used for prevention of vertical viral transmission, however evidence of genotoxicity in mouse and monkey models and in the infants themselves would suggest that exposed children should be followed well past adolescence for early detection of potential cancer hazard

Leishmaniasis vector behaviour in Kenya

International Nuclear Information System (INIS)

Mutinga, M.J.

1980-01-01

Leishmaniasis in Kenya exists in two forms: cutaneous and visceral. The vectors of visceral leishmaniasis have been the subject of investigation by various researchers since World War II, when the outbreak of the disease was first noticed. The vectors of cutaneous leishmaniasis were first worked on only a decade ago after the discovery of the disease focus in Mt. Elgon. The vector behaviour of these diseases, namely Phlebotomus pedifer, the vector of cutaneous leishmaniasis, and Phlebotomus martini, the vector of visceral leishmaniasis, are discussed in detail. P. pedifer has been found to breed and bite inside caves, whereas P. martini mainly bites inside houses. (author)

Anti-inflammatory and vasoprotective activity of a retroviral-derived peptide, homologous to human endogenous retroviruses: endothelial cell effects.

Directory of Open Access Journals (Sweden)

George J Cianciolo

Full Text Available Malignant and inflammatory tissues sometimes express endogenous retroviruses or their proteins. A highly-conserved sequence from retroviral transmembrane (TM proteins, termed the "immunosuppressive domain (ID", is associated with inhibition of immune and inflammatory functions. An octadecapeptide (MN10021 from the ID of retroviral TM protein p15E inhibits in vitro release of pro-inflammatory cytokines and increases synthesis of anti-inflammatory IL-10. We sought to determine if MN10021 has significant in vivo effects. MN10021, prepared by solid-phase synthesis, was dimerized through a naturally-occurring, carboxy-terminal cysteine. In vivo anti-inflammatory activity was determined using a murine model of sodium periodate (NaIO(4-induced peritonitis. In vivo vasoprotective effects were determined using: (1 a carrageenan-induced model of disseminated intravascular coagulation (DIC in mice; (2 a reverse passive Arthus model in guinea pigs; and (3 vasoregulatory effects in spontaneously hypertensive rats (SHR. In vitro studies included: (1 binding/uptake of MN10021 using human monocytes, cultured fibroblasts, and vascular endothelial cells (VEC; (2 gene expression by RT-PCR of MN10021-treated VEC; and (3 apoptosis of MN10021-treated VEC exposed to staurosporine or TNF-α. One-tenth nmol MN10021 inhibits 50 percent of the inflammatory response in the mouse peritonitis model. Furthermore, 73 nmol MN10021 completely protects mice in a lethal model of carrageenan-induced DIC and inhibits vascular leak in both the mouse DIC model and a guinea pig reverse passive Arthus reaction. MN10021 binds to and is taken up in a specific manner by both human monocytes and VEC but not by cultured human fibroblasts. Surprisingly, orally-administered MN10021 lowers blood pressure in SHR rats by 10-15% within 1 h suggesting a direct or indirect effect on the vascular endothelium. MN10021 and derived octapeptides induce iNOS (inducible nitric oxide synthase mRNA in VEC

Learning with LOGO: Logo and Vectors.

Science.gov (United States)

Lough, Tom; Tipps, Steve

1986-01-01

This is the first of a two-part series on the general concept of vector space. Provides tool procedures to allow investigation of vector properties, vector addition and subtraction, and X and Y components. Lists several sources of additional vector ideas. (JM)

Cloning and Characterization of a Cell Senescence Gene for Breast Cancer Cells

Science.gov (United States)

2004-07-01

have already established the inducible expression system in a retroviral vector for these studies. F. References 1. Hayflick , L. (1965). The limited ...CLASSIFICATION 18. SECURITY CLASSIFICATION 19. SECURITY CLASSIFICATION 20. LIMITATION OF ABSTRACT OF REPORT OF THIS PAGE OFABSTRACT Unclassified...13-14 Annual report A. Introduction Normal diploid mammalian cells display a limited proliferative life span in culture (1-3

Inclusion of Moloney murine leukemia virus elements upstream of the transgene cassette in an E1-deleted adenovirus leads to an unusual genomic integration in epithelial cells

International Nuclear Information System (INIS)

Zheng Changyu; O'Connell, Brian C.; Baum, Bruce J.

2003-01-01

Classically, the 5' and 3' long terminal repeats (LTRs) are considered necessary but not sufficient for retroviral integration. Recently, we reported that inclusion of these and additional elements from Moloney murine leukemia virus (MoMLV) facilitated transgene integration, without retroviral integrase, when placed in an adenoviral context (AdLTR-luc vector) (Nat. Biotech. 18 (2000), 176; Biochem. Biophys. Res. Commun. 300 (2003), 115). To help understand this nonhomologous DNA recombination event, we constructed another vector, AdELP-luc, with 2.7 kb of MoMLV elements identically placed into an E1-deleted adenovirus type 5 backbone upstream of a luciferase cDNA reporter gene. Unlike AdLTR-luc, no MoMLV elements were placed downstream of the expression cassette. AdELP-luc readily infected epithelial cells in vitro. Southern hybridizations with DNA from cloned cells showed that disruption of the MoMLV sequences occurred. One cell clone, grown in vitro without any special selection medium for 9 months, exhibited stable vector integration and luciferase activity. Importantly, both Southern hybridization and FISH analyses showed that in addition to the MoMLV elements and expression cassette, substantial adenoviral sequence downstream of the luciferase cDNA was genomically integrated. These results suggest that the 2.7 kb of MoMLV sequence included in AdELP-luc have cis-acting functions and mediates an unusual integration event

Strangeness Vector and Axial-Vector Form Factors of the Nucleon

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Pate Stephen

2014-03-01

Full Text Available A revised global fit of electroweak ep and vp elastic scattering data has been performed, with the goal of determining the strange quark contribution to the vector and axial-vector form factors of the nucleon in the momentum-transfer range 0 < Q2 < 1 GeV2. The two vector (electric and magnetic form factors GsE(Q2 and GsM(Q2 are strongly constrained by ep elastic scattering data, while the major source of information on the axial-vector form factor GsA(Q2 is vp scattering data. Combining the two kinds of data into a single global fit makes possible additional precision in the determination of these form factors, and provides a unique way to determine the strange quark contribution to the nucleon spin, ΔS , independently of leptonic deep-inelastic scattering. The fit makes use of data from the BNL-E734, SAMPLE, HAPPEx, G0, and PVA4 experiments; we will also compare the result of the fit with recent data from MiniBooNE, and anticipate how this fit can be improved when new data from MicroBooNE become available.

Multi-task Vector Field Learning.

Science.gov (United States)

Lin, Binbin; Yang, Sen; Zhang, Chiyuan; Ye, Jieping; He, Xiaofei

2012-01-01

Multi-task learning (MTL) aims to improve generalization performance by learning multiple related tasks simultaneously and identifying the shared information among tasks. Most of existing MTL methods focus on learning linear models under the supervised setting. We propose a novel semi-supervised and nonlinear approach for MTL using vector fields. A vector field is a smooth mapping from the manifold to the tangent spaces which can be viewed as a directional derivative of functions on the manifold. We argue that vector fields provide a natural way to exploit the geometric structure of data as well as the shared differential structure of tasks, both of which are crucial for semi-supervised multi-task learning. In this paper, we develop multi-task vector field learning (MTVFL) which learns the predictor functions and the vector fields simultaneously. MTVFL has the following key properties. (1) The vector fields MTVFL learns are close to the gradient fields of the predictor functions. (2) Within each task, the vector field is required to be as parallel as possible which is expected to span a low dimensional subspace. (3) The vector fields from all tasks share a low dimensional subspace. We formalize our idea in a regularization framework and also provide a convex relaxation method to solve the original non-convex problem. The experimental results on synthetic and real data demonstrate the effectiveness of our proposed approach.

Transcription Profiling Demonstrates Epigenetic Control of Non-retroviral RNA Virus-Derived Elements in the Human Genome

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Kozue Sofuku

2015-09-01

Full Text Available Endogenous bornavirus-like nucleoprotein elements (EBLNs are DNA sequences in vertebrate genomes formed by the retrotransposon-mediated integration of ancient bornavirus sequence. Thus, EBLNs evidence a mechanism of retrotransposon-mediated RNA-to-DNA information flow from environment to animals. Although EBLNs are non-transposable, they share some features with retrotransposons. Here, to test whether hosts control the expression of EBLNs similarly to retrotransposons, we profiled the transcription of all Homo sapiens EBLNs (hsEBLN-1 to hsEBLN-7. We could detect transcription of all hsEBLNs in at least one tissue. Among them, hsEBLN-1 is transcribed almost exclusively in the testis. In most tissues, expression from the hsEBLN-1 locus is silenced epigenetically. Finally, we showed the possibility that hsEBLN-1 integration at this locus affects the expression of a neighboring gene. Our results suggest that hosts regulate the expression of endogenous non-retroviral virus elements similarly to how they regulate the expression of retrotransposons, possibly contributing to new transcripts and regulatory complexity to the human genome.

Enhancing poxvirus vectors vaccine immunogenicity.

Science.gov (United States)

García-Arriaza, Juan; Esteban, Mariano

2014-01-01

Attenuated recombinant poxvirus vectors expressing heterologous antigens from pathogens are currently at various stages in clinical trials with the aim to establish their efficacy. This is because these vectors have shown excellent safety profiles, significant immunogenicity against foreign expressed antigens and are able to induce protective immune responses. In view of the limited efficacy triggered by some poxvirus strains used in clinical trials (i.e, ALVAC in the RV144 phase III clinical trial for HIV), and of the restrictive replication capacity of the highly attenuated vectors like MVA and NYVAC, there is a consensus that further improvements of these vectors should be pursuit. In this review we considered several strategies that are currently being implemented, as well as new approaches, to improve the immunogenicity of the poxvirus vectors. This includes heterologous prime/boost protocols, use of co-stimulatory molecules, deletion of viral immunomodulatory genes still present in the poxvirus genome, enhancing virus promoter strength, enhancing vector replication capacity, optimizing expression of foreign heterologous sequences, and the combined use of adjuvants. An optimized poxvirus vector triggering long-lasting immunity with a high protective efficacy against a selective disease should be sought.

Stable piecewise polynomial vector fields

Directory of Open Access Journals (Sweden)

Claudio Pessoa

2012-09-01

Full Text Available Let $N={y>0}$ and $S={y<0}$ be the semi-planes of $mathbb{R}^2$ having as common boundary the line $D={y=0}$. Let $X$ and $Y$ be polynomial vector fields defined in $N$ and $S$, respectively, leading to a discontinuous piecewise polynomial vector field $Z=(X,Y$. This work pursues the stability and the transition analysis of solutions of $Z$ between $N$ and $S$, started by Filippov (1988 and Kozlova (1984 and reformulated by Sotomayor-Teixeira (1995 in terms of the regularization method. This method consists in analyzing a one parameter family of continuous vector fields $Z_{epsilon}$, defined by averaging $X$ and $Y$. This family approaches $Z$ when the parameter goes to zero. The results of Sotomayor-Teixeira and Sotomayor-Machado (2002 providing conditions on $(X,Y$ for the regularized vector fields to be structurally stable on planar compact connected regions are extended to discontinuous piecewise polynomial vector fields on $mathbb{R}^2$. Pertinent genericity results for vector fields satisfying the above stability conditions are also extended to the present case. A procedure for the study of discontinuous piecewise vector fields at infinity through a compactification is proposed here.

Transversals of Complex Polynomial Vector Fields

DEFF Research Database (Denmark)

Dias, Kealey

Vector fields in the complex plane are defined by assigning the vector determined by the value P(z) to each point z in the complex plane, where P is a polynomial of one complex variable. We consider special families of so-called rotated vector fields that are determined by a polynomial multiplied...... by rotational constants. Transversals are a certain class of curves for such a family of vector fields that represent the bifurcation states for this family of vector fields. More specifically, transversals are curves that coincide with a homoclinic separatrix for some rotation of the vector field. Given...... a concrete polynomial, it seems to take quite a bit of work to prove that it is generic, i.e. structurally stable. This has been done for a special class of degree d polynomial vector fields having simple equilibrium points at the d roots of unity, d odd. In proving that such vector fields are generic...

Vector optimization set-valued and variational analysis

CERN Document Server

Chen, Guang-ya; Yang, Xiaogi

2005-01-01

This book is devoted to vector or multiple criteria approaches in optimization. Topics covered include: vector optimization, vector variational inequalities, vector variational principles, vector minmax inequalities and vector equilibrium problems. In particular, problems with variable ordering relations and set-valued mappings are treated. The nonlinear scalarization method is extensively used throughout the book to deal with various vector-related problems. The results presented are original and should be interesting to researchers and graduates in applied mathematics and operations research

Implicit Real Vector Automata

Directory of Open Access Journals (Sweden)

Jean-François Degbomont

2010-10-01

Full Text Available This paper addresses the symbolic representation of non-convex real polyhedra, i.e., sets of real vectors satisfying arbitrary Boolean combinations of linear constraints. We develop an original data structure for representing such sets, based on an implicit and concise encoding of a known structure, the Real Vector Automaton. The resulting formalism provides a canonical representation of polyhedra, is closed under Boolean operators, and admits an efficient decision procedure for testing the membership of a vector.

Vectoring of parallel synthetic jets

Science.gov (United States)

Berk, Tim; Ganapathisubramani, Bharathram; Gomit, Guillaume

2015-11-01

A pair of parallel synthetic jets can be vectored by applying a phase difference between the two driving signals. The resulting jet can be merged or bifurcated and either vectored towards the actuator leading in phase or the actuator lagging in phase. In the present study, the influence of phase difference and Strouhal number on the vectoring behaviour is examined experimentally. Phase-locked vorticity fields, measured using Particle Image Velocimetry (PIV), are used to track vortex pairs. The physical mechanisms that explain the diversity in vectoring behaviour are observed based on the vortex trajectories. For a fixed phase difference, the vectoring behaviour is shown to be primarily influenced by pinch-off time of vortex rings generated by the synthetic jets. Beyond a certain formation number, the pinch-off timescale becomes invariant. In this region, the vectoring behaviour is determined by the distance between subsequent vortex rings. We acknowledge the financial support from the European Research Council (ERC grant agreement no. 277472).

Vectorization in quantum chemistry

International Nuclear Information System (INIS)

Saunders, V.R.

1987-01-01

It is argued that the optimal vectorization algorithm for many steps (and sub-steps) in a typical ab initio calculation of molecular electronic structure is quite strongly dependent on the target vector machine. Details such as the availability (or lack) of a given vector construct in the hardware, vector startup times and asymptotic rates must all be considered when selecting the optimal algorithm. Illustrations are drawn from: gaussian integral evaluation, fock matrix construction, 4-index transformation of molecular integrals, direct-CI methods, the matrix multiply operation. A cross comparison of practical implementations on the CDC Cyber 205, the Cray-IS and Cray-XMP machines is presented. To achieve portability while remaining optimal on a wide range of machines it is necessary to code all available algorithms in a machine independent manner, and to select the appropriate algorithm using a procedure which is based on machine dependent parameters. Most such parameters concern the timing of certain vector loop kernals, which can usually be derived from a 'bench-marking' routine executed prior to the calculation proper

Properties of vector and axial-vector mesons from a generalized Nambu-Jona-Lasinio model

International Nuclear Information System (INIS)

Bernard, V.; Meissner, U.G.; Massachusetts Inst. of Tech., Cambridge; Massachusetts Inst. of Tech., Cambridge

1988-01-01

We construct a generalized Nambu-Jona-Lasinio lagrangian including scalar, pseudoscalar, vector and axial-vector mesons. We specialize to the two-flavor case. The properties of the structured vacuum as well as meson masses and coupling constants are calculated giving an overall agreement within 20% of the experimental data. We investigate the meson properties at finite density. In contrast to the mass of the scalar σ-meson, which decreases sharply with increasing density, the vector meson masses are almost independent of density. Furthermore, the vector-meson-quark coupling constants are also stable against density changes. We point out that these results imply a softening of the nuclear equation of state at high densities. Furthermore, we discuss the breakdown of the KFSR relation on the quark level as well as other deviations from phenomenological concepts such as universality and vector meson dominance. (orig.)

Vector geometry

CERN Document Server

Robinson, Gilbert de B

2011-01-01

This brief undergraduate-level text by a prominent Cambridge-educated mathematician explores the relationship between algebra and geometry. An elementary course in plane geometry is the sole requirement for Gilbert de B. Robinson's text, which is the result of several years of teaching and learning the most effective methods from discussions with students. Topics include lines and planes, determinants and linear equations, matrices, groups and linear transformations, and vectors and vector spaces. Additional subjects range from conics and quadrics to homogeneous coordinates and projective geom

Electroproduction and photoproduction of vector mesons and generalized vector meson dominance

International Nuclear Information System (INIS)

Fraas, H.; Kuroda, M.

1977-05-01

Using generalized vector meson dominance, electro- and photoproduction of vector mesons is studied. The unnatural parity exchange part of ω(1.2) production is estimated to be about one fourth of that of ω-production. The off diagonal transition model suggests the suppression of diffractive rho(1.2) and ω(1.2) production. (orig.) [de

Vector (two-dimensional) magnetic phenomena

International Nuclear Information System (INIS)

Enokizono, Masato

2002-01-01

In this paper, some interesting phenomena were described from the viewpoint of two-dimensional magnetic property, which is reworded with the vector magnetic property. It shows imperfection of conventional magnetic property and some interested phenomena were discovered, too. We found magnetic materials had the strong nonlinearity both magnitude and spatial phase due to the relationship between the magnetic field strength H-vector and the magnetic flux density B-vector. Therefore, magnetic properties should be defined as the vector relationship. Furthermore, the new Barukhausen signal was observed under rotating flux. (Author)

Quark-gluon plasma tomography by vector mesons

International Nuclear Information System (INIS)

Lovas, I.; Schram, Zs.; Csernai, L.P.; Hungarian Academy of Sciences, Budapest; Nyiri, A.

2001-01-01

The fireball formed in a heavy ion collision is characterized by the impact parameter vector b-vector, which can be determined from the multiplicity and the angular distribution of the reaction products. By appropriate rotations the b-vector vectors of each collision can be aligned into a fixed direction. Using the measured values of the momentum distributions independent integral equations can be formulated for the unknown emission densities (E M (r-vector)) and for the unknown absorption densities (Δμ(r-vector)) of the different vector mesons. (author)

Vector superconductivity in cosmic strings

International Nuclear Information System (INIS)

Dvali, G.R.; Mahajan, S.M.

1992-03-01

We argue that in most realistic cases, the usual Witten-type bosonic superconductivity of the cosmic string is automatically (independent of the existence of superconducting currents) accompanied by the condensation of charged gauge vector bosons in the core giving rise to a new vector type superconductivity. The value of the charged vector condensate is related with the charged scalar expectation value, and vanishes only if the latter goes to zero. The mechanism for the proposed vector superconductivity, differing fundamentally from those in the literature, is delineated using the simplest realistic example of the two Higgs doublet standard model interacting with the extra cosmic string. It is shown that for a wide range of parameters, for which the string becomes scalarly superconducting, W boson condensates (the sources of vector superconductivity) are necessarily excited. (author). 14 refs

Brane vector phenomenology

International Nuclear Information System (INIS)

Clark, T.E.; Love, S.T.; Nitta, Muneto; Veldhuis, T. ter; Xiong, C.

2009-01-01

Local oscillations of the brane world are manifested as massive vector fields. Their coupling to the Standard Model can be obtained using the method of nonlinear realizations of the spontaneously broken higher-dimensional space-time symmetries, and to an extent, are model independent. Phenomenological limits on these vector field parameters are obtained using LEP collider data and dark matter constraints

Distribution of Brugia malayi larvae and DNA in vector and non-vector mosquitoes: implications for molecular diagnostics

Directory of Open Access Journals (Sweden)

Christensen Bruce M

2009-11-01

Full Text Available Abstract Background The purpose of this study was to extend prior studies of molecular detection of Brugia malayi DNA in vector (Aedes aegypti- Liverpool and non-vector (Culex pipiens mosquitoes at different times after ingestion of infected blood. Results Parasite DNA was detected over a two week time course in 96% of pooled thoraces of vector mosquitoes. In contrast, parasite DNA was detected in only 24% of thorax pools from non-vectors; parasite DNA was detected in 56% of midgut pools and 47% of abdomen pools from non-vectors. Parasite DNA was detected in vectors in the head immediately after the blood meal and after 14 days. Parasite DNA was also detected in feces and excreta of the vector and non-vector mosquitoes which could potentially confound results obtained with field samples. However, co-housing experiments failed to demonstrate transfer of parasite DNA from infected to non-infected mosquitoes. Parasites were also visualized in mosquito tissues by immunohistololgy using an antibody to the recombinant filarial antigen Bm14. Parasite larvae were detected consistently after mf ingestion in Ae. aegypti- Liverpool. Infectious L3s were seen in the head, thorax and abdomen of vector mosquitoes 14 days after Mf ingestion. In contrast, parasites were only detected by histology shortly after the blood meal in Cx. pipiens, and these were not labeled by the antibody. Conclusion This study provides new information on the distribution of filarial parasites and parasite DNA in vector and non-vector mosquitoes. This information should be useful for those involved in designing and interpreting molecular xenomonitoring studies.

Human heme oxygenase-1 gene transfer lowers blood pressure and promotes growth in spontaneously hypertensive rats.

Science.gov (United States)

Sabaawy, H E; Zhang, F; Nguyen, X; ElHosseiny, A; Nasjletti, A; Schwartzman, M; Dennery, P; Kappas, A; Abraham, N G

2001-08-01

Heme oxygenase (HO) catalyzes the conversion of heme to biliverdin, with release of free iron and carbon monoxide. Both heme and carbon monoxide have been implicated in the regulation of vascular tone. A retroviral vector containing human HO-1 cDNA (LSN-HHO-1) was constructed and subjected to purification and concentration of the viral particles to achieve 5x10(9) to 1x10(10) colony-forming units per milliliter. The ability of concentrated infectious viral particles to express human HO-1 (HHO-1) in vivo was tested. A single intracardiac injection of the concentrated infectious viral particles (expressing HHO-1) to 5-day-old spontaneously hypertensive rats resulted in functional expression of the HHO-1 gene and attenuation of the development of hypertension. Rats expressing HHO-1 showed a significant decrease in urinary excretion of a vasoconstrictor arachidonic acid metabolite and a reduction in myogenic responses to increased intraluminal pressure in isolated arterioles. Unexpectedly, HHO-1 chimeric rats showed a simultaneous significant proportionate increase in somatic growth. Thus, delivery of HHO-1 gene by retroviral vector attenuates the development of hypertension and promotes body growth in spontaneously hypertensive rats.

Insecticide resistance in disease vectors from Mayotte: an opportunity for integrated vector management.

Science.gov (United States)

Pocquet, Nicolas; Darriet, Frédéric; Zumbo, Betty; Milesi, Pascal; Thiria, Julien; Bernard, Vincent; Toty, Céline; Labbé, Pierrick; Chandre, Fabrice

2014-07-01

Mayotte, a small island in the Indian Ocean, has been affected for many years by vector-borne diseases. Malaria, Bancroftian filariasis, dengue, chikungunya and Rift Valley fever have circulated or still circulate on the island. They are all transmitted by Culicidae mosquitoes. To limit the impact of these diseases on human health, vector control has been implemented for more than 60 years on Mayotte. In this study, we assessed the resistance levels of four major vector species (Anopheles gambiae, Culex pipiens quinquefasciatus, Aedes aegypti and Aedes albopictus) to two types of insecticides: i) the locally currently-used insecticides (organophosphates, pyrethroids) and ii) alternative molecules that are promising for vector control and come from different insecticide families (bacterial toxins or insect growth regulators). When some resistance was found to one of these insecticides, we characterized the mechanisms involved. Larval and adult bioassays were used to evaluate the level of resistance. When resistance was found, we tested for the presence of metabolic resistance through detoxifying enzyme activity assays, or for target-site mutations through molecular identification of known resistance alleles. Resistance to currently-used insecticides varied greatly between the four vector species. While no resistance to any insecticides was found in the two Aedes species, bioassays confirmed multiple resistance in Cx. p. quinquefasciatus (temephos: ~ 20 fold and deltamethrin: only 10% mortality after 24 hours). In An. gambiae, resistance was scarce: only a moderate resistance to temephos was found (~5 fold). This resistance appears to be due only to carboxyl-esterase overexpression and not to target modification. Finally, and comfortingly, none of the four species showed resistance to any of the new insecticides. The low resistance observed in Mayotte's main disease vectors is particularly interesting, because it leaves a range of tools useable by vector control

Tensor Calculus: Unlearning Vector Calculus

Science.gov (United States)

Lee, Wha-Suck; Engelbrecht, Johann; Moller, Rita

2018-01-01

Tensor calculus is critical in the study of the vector calculus of the surface of a body. Indeed, tensor calculus is a natural step-up for vector calculus. This paper presents some pitfalls of a traditional course in vector calculus in transitioning to tensor calculus. We show how a deeper emphasis on traditional topics such as the Jacobian can…

Induction of Type I Interferons by Therapeutic Nanoparticle-Based Vaccination Is Indispensable to Reinforce Cytotoxic CD8+ T Cell Responses During Chronic Retroviral Infection

Science.gov (United States)

Knuschke, Torben; Rotan, Olga; Bayer, Wibke; Kollenda, Sebastian; Dickow, Julia; Sutter, Kathrin; Hansen, Wiebke; Dittmer, Ulf; Lang, Karl S.; Epple, Matthias; Buer, Jan; Westendorf, Astrid M.

2018-01-01

T cell dysfunction and immunosuppression are characteristic for chronic viral infections and contribute to viral persistence. Overcoming these burdens is the goal of new therapeutic strategies to cure chronic infectious diseases. We recently described that therapeutic vaccination of chronic retrovirus infected mice with a calcium phosphate (CaP) nanoparticle (NP)-based vaccine carrier, functionalized with CpG and viral peptides is able to efficiently reactivate the CD8+ T cell response and improve the eradication of virus infected cells. However, the mechanisms underlying this effect were largely unclear. While type I interferons (IFNs I) are considered to drive T cell exhaustion by persistent immune activation during chronic viral infection, we here describe an indispensable role of IFN I induced by therapeutic vaccination to efficiently reinforce cytotoxic CD8+ T cells (CTL) and improve control of chronic retroviral infection. The induction of IFN I is CpG dependent and leads to significant IFN signaling indicated by upregulation of IFN stimulated genes. By vaccinating chronically retrovirus-infected mice lacking the IFN I receptor (IFNAR−/−) or by blocking IFN I signaling in vivo during therapeutic vaccination, we demonstrate that IFN I signaling is necessary to drive full reactivation of CTLs. Surprisingly, we also identified an impaired suppressive capability of regulatory T cells in the presence of IFNα, which implicates an important role for vaccine-induced IFNα in the regulation of the T cell response during chronic retroviral infection. Our data suggest that inducing IFN I signaling in conjunction with the presentation of viral antigens can reactivate immune functions and reduce viral loads in chronic infections. Therefore, we propose CaP NPs as potential therapeutic tool to treat chronic infections. PMID:29740425

Vector mesons on the light front

International Nuclear Information System (INIS)

Naito, K.; Maedan, S.; Itakura, K.

2004-01-01

We apply the light-front quantization to the Nambu-Jona-Lasinio model with the vector interaction, and compute vector meson's mass and light-cone wavefunction in the large N limit. Following the same procedure as in the previous analyses for scalar and pseudo-scalar mesons, we derive the bound-state equations of a qq-bar system in the vector channel. We include the lowest order effects of the vector interaction. The resulting transverse and longitudinal components of the bound-state equation look different from each other. But eventually after imposing an appropriate cutoff, one finds these two are identical, giving the same mass and the same (spin-independent) light-cone wavefunction. Mass of the vector meson decreases as one increases the strength of the vector interaction

Does the delta quench Gamow-Teller strength in (p,n)- and (p vector,p vector')-reactions

International Nuclear Information System (INIS)

Osterfeld, F.; Schulte, A.; Udagawa, T.; Yabe, M.

1986-01-01

Microscopic analyses of complete forward angle intermediate energy (p,n)-, ( 3 He,t)- and (p vector,p vector')-spin-flip spectra are presented for the reactions 90 Zr(p,n), 90 Zr( 3 He,t) and 90 Zr(p vector,p vector'). It is shown that the whole spectra up to high excitation energies (E X ∝50 MeV) are the result of correlated one-particle-one-hole (1p1h) spin-isospin transitions only. The spectra reflect, therefore, the linear spin-isospin response of the target nucleus to the probing external hadronic fields. Our results suggest that the measured (p,n)-, ( 3 He,t)- and (p vector,p vector')-cross sections are compatible with the transition strength predictions as obtained from random phase approximation (RPA) calculations. This means that the Δ isobar quenching mechanism is likely to be rather small. (orig.)

The second chance story of HIV-1 DNA: Unintegrated? Not a problem!

Science.gov (United States)

Wu, Yuntao

2008-07-09

Accumulation of high levels of unintegrated viral DNA is a common feature of retroviral infection. It was recently discovered that coinfection of cells with integrated and unintegrated HIV-1 can result in complementation, allowing viral replication in the absence of integration. This new mode of HIV-1 replication has numerous implications for the function of unintegrated viral DNA and its application as a therapeutic vector.

On the Vectorization of FIR Filterbanks

Directory of Open Access Journals (Sweden)

Barbedo Jayme Garcia Arnal

2007-01-01

Full Text Available This paper presents a vectorization technique to implement FIR filterbanks. The word vectorization, in the context of this work, refers to a strategy in which all iterative operations are replaced by equivalent vector and matrix operations. This approach allows that the increasing parallelism of the most recent computer processors and systems be properly explored. The vectorization techniques are applied to two kinds of FIR filterbanks (conventional and recursi ve, and are presented in such a way that they can be easily extended to any kind of FIR filterbanks. The vectorization approach is compared to other kinds of implementation that do not explore the parallelism, and also to a previous FIR filter vectorization approach. The tests were performed in Matlab and , in order to explore different aspects of the proposed technique.

On the Vectorization of FIR Filterbanks

Directory of Open Access Journals (Sweden)

Amauri Lopes

2007-01-01

Full Text Available This paper presents a vectorization technique to implement FIR filterbanks. The word vectorization, in the context of this work, refers to a strategy in which all iterative operations are replaced by equivalent vector and matrix operations. This approach allows that the increasing parallelism of the most recent computer processors and systems be properly explored. The vectorization techniques are applied to two kinds of FIR filterbanks (conventional and recursi ve, and are presented in such a way that they can be easily extended to any kind of FIR filterbanks. The vectorization approach is compared to other kinds of implementation that do not explore the parallelism, and also to a previous FIR filter vectorization approach. The tests were performed in Matlab and C, in order to explore different aspects of the proposed technique.

Two-hadron saturation for the pseudoscalar-vector-vector correlator and phenomenological applications

Energy Technology Data Exchange (ETDEWEB)

Husek, Tomas [Charles University, Faculty of Mathematics and Physics, Institute of Particle and Nuclear Physics, Prague 8 (Czech Republic); Leupold, Stefan [Uppsala Universitet, Institutionen foer Fysik och Astronomi, Box 516, Uppsala (Sweden)

2015-12-15

The pseudoscalar-vector-vector correlator is constructed using two meson multiplets in the vector and two in the pseudoscalar channel. The parameters are constrained by the operator product expansion at leading order where two or all three momenta are considered as large. Demanding in addition the Brodsky-Lepage limit one obtains (in the chiral limit) pion-vector-vector (πVV) correlator with only one free parameter. The singly virtual pion transition form factor F{sub π{sup 0}γγ*} and the decay width of ω → π{sup 0}γ are independent of this parameter and can serve as cross-checks of the results. The free parameter is determined from a fit of the ω-π transition form factor F{sub π{sup 0}ωγ*}. The resulting πVV correlator is used to calculate the decay widths ω → π{sup 0}e{sup +}e{sup -} and ω → π{sup 0}μ{sup +}μ{sup -} and finally the widths of the rare decay π{sup 0} → e{sup +}e{sup -} and of the Dalitz decay π{sup 0} → e{sup +}e{sup -}γ. Incorporating radiative QED corrections the calculations of π{sup 0} decays are compared to the KTeV results. We find a deviation of 2 σ or less for the rare pion decay. (orig.)

Endogenous Retroviral Insertions Indicate a Secondary Introduction of Domestic Sheep Lineages to the Caucasus and Central Asia between the Bronze and Iron Age

Science.gov (United States)

Schroeder, Oskar; Benecke, Norbert; Frölich, Kai; Peng, Zuogang; Kaniuth, Kai; Sverchkov, Leonid; Reinhold, Sabine; Belinskiy, Andrey; Ludwig, Arne

2017-01-01

Sheep were one of the first livestock species domesticated by humans. After initial domestication in the Middle East they were spread across Eurasia. The modern distribution of endogenous Jaagsiekte sheep retrovirus insertions in domestic sheep breeds suggests that over the course of millennia, successive introductions of improved lineages and selection for wool quality occurred in the Mediterranean region and most of Asia. Here we present a novel ancient DNA approach using data of endogenous retroviral insertions in Bronze and Iron Age domestic sheep from the Caucasus and Pamir mountain areas. Our findings support a secondary introduction of wool sheep from the Middle East between the Late Bronze Age and Iron Age into most areas of Eurasia. PMID:28632161

Endogenous Retroviral Insertions Indicate a Secondary Introduction of Domestic Sheep Lineages to the Caucasus and Central Asia between the Bronze and Iron Age

Directory of Open Access Journals (Sweden)

Oskar Schroeder

2017-06-01

Full Text Available Sheep were one of the first livestock species domesticated by humans. After initial domestication in the Middle East they were spread across Eurasia. The modern distribution of endogenous Jaagsiekte sheep retrovirus insertions in domestic sheep breeds suggests that over the course of millennia, successive introductions of improved lineages and selection for wool quality occurred in the Mediterranean region and most of Asia. Here we present a novel ancient DNA approach using data of endogenous retroviral insertions in Bronze and Iron Age domestic sheep from the Caucasus and Pamir mountain areas. Our findings support a secondary introduction of wool sheep from the Middle East between the Late Bronze Age and Iron Age into most areas of Eurasia.

Vector borne diseases

OpenAIRE

Melillo Fenech, Tanya

2010-01-01

A vector-borne disease is one in which the pathogenic microorganism is transmitted from an infected individual to another individual by an arthropod or other agent. The transmission depends upon the attributes and requirements of at least three different Iiving organisms : the pathologic agent which is either a virus, protozoa, bacteria or helminth (worm); the vector, which is commonly an arthropod such as ticks or mosquitoes; and the human host.

Scanning vector Hall probe microscopy

International Nuclear Information System (INIS)

Cambel, V.; Gregusova, D.; Fedor, J.; Kudela, R.; Bending, S.J.

2004-01-01

We have developed a scanning vector Hall probe microscope for mapping magnetic field vector over magnetic samples. The microscope is based on a micromachined Hall sensor and the cryostat with scanning system. The vector Hall sensor active area is ∼5x5 μm 2 . It is realized by patterning three Hall probes on the tilted faces of GaAs pyramids. Data from these 'tilted' Hall probes are used to reconstruct the full magnetic field vector. The scanning area of the microscope is 5x5 mm 2 , space resolution 2.5 μm, field resolution ∼1 μT Hz -1/2 at temperatures 10-300 K

Non-coaxial superposition of vector vortex beams.

Science.gov (United States)

Aadhi, A; Vaity, Pravin; Chithrabhanu, P; Reddy, Salla Gangi; Prabakar, Shashi; Singh, R P

2016-02-10

Vector vortex beams are classified into four types depending upon spatial variation in their polarization vector. We have generated all four of these types of vector vortex beams by using a modified polarization Sagnac interferometer with a vortex lens. Further, we have studied the non-coaxial superposition of two vector vortex beams. It is observed that the superposition of two vector vortex beams with same polarization singularity leads to a beam with another kind of polarization singularity in their interaction region. The results may be of importance in ultrahigh security of the polarization-encrypted data that utilizes vector vortex beams and multiple optical trapping with non-coaxial superposition of vector vortex beams. We verified our experimental results with theory.

Fractal vector optical fields.

Science.gov (United States)

Pan, Yue; Gao, Xu-Zhen; Cai, Meng-Qiang; Zhang, Guan-Lin; Li, Yongnan; Tu, Chenghou; Wang, Hui-Tian

2016-07-15

We introduce the concept of a fractal, which provides an alternative approach for flexibly engineering the optical fields and their focal fields. We propose, design, and create a new family of optical fields-fractal vector optical fields, which build a bridge between the fractal and vector optical fields. The fractal vector optical fields have polarization states exhibiting fractal geometry, and may also involve the phase and/or amplitude simultaneously. The results reveal that the focal fields exhibit self-similarity, and the hierarchy of the fractal has the "weeding" role. The fractal can be used to engineer the focal field.

Clifford Fourier transform on vector fields.

Science.gov (United States)

Ebling, Julia; Scheuermann, Gerik

2005-01-01

Image processing and computer vision have robust methods for feature extraction and the computation of derivatives of scalar fields. Furthermore, interpolation and the effects of applying a filter can be analyzed in detail and can be advantages when applying these methods to vector fields to obtain a solid theoretical basis for feature extraction. We recently introduced the Clifford convolution, which is an extension of the classical convolution on scalar fields and provides a unified notation for the convolution of scalar and vector fields. It has attractive geometric properties that allow pattern matching on vector fields. In image processing, the convolution and the Fourier transform operators are closely related by the convolution theorem and, in this paper, we extend the Fourier transform to include general elements of Clifford Algebra, called multivectors, including scalars and vectors. The resulting convolution and derivative theorems are extensions of those for convolution and the Fourier transform on scalar fields. The Clifford Fourier transform allows a frequency analysis of vector fields and the behavior of vector-valued filters. In frequency space, vectors are transformed into general multivectors of the Clifford Algebra. Many basic vector-valued patterns, such as source, sink, saddle points, and potential vortices, can be described by a few multivectors in frequency space.

Vector-like quarks: t’ and partners

International Nuclear Information System (INIS)

PANIZZI, L.

2014-01-01

Vector-like quarks are predicted in various scenarios of new physics, and their peculiar signatures from both pair and single production have been already investigated in detail. However no signals of vector-like quarks have been detected so far, pushing limits on their masses above 600–700GeV, depending on assumptions on their couplings. Experimental searches consider specific final states to pose bounds on the mass of a vector-like quark, usually assuming it is the only particle that contributes to the signal of new physics in that specific final state. However, realistic scenarios predict the existence of multiple vector-like quarks, possibly with similar masses. The reinterpretation of mass bounds from experimental searches is therefore not always straightforward. In this analysis I briefly summarise the constraints on vector-like quarks and their possible signatures at the LHC, focusing in particular on a model-independent description of single production processes for vector-like quark that mix with all generations and on the development of a framework to study scenarios with multiple vector-like quarks.

Correlated Topic Vector for Scene Classification.

Science.gov (United States)

Wei, Pengxu; Qin, Fei; Wan, Fang; Zhu, Yi; Jiao, Jianbin; Ye, Qixiang

2017-07-01

Scene images usually involve semantic correlations, particularly when considering large-scale image data sets. This paper proposes a novel generative image representation, correlated topic vector, to model such semantic correlations. Oriented from the correlated topic model, correlated topic vector intends to naturally utilize the correlations among topics, which are seldom considered in the conventional feature encoding, e.g., Fisher vector, but do exist in scene images. It is expected that the involvement of correlations can increase the discriminative capability of the learned generative model and consequently improve the recognition accuracy. Incorporated with the Fisher kernel method, correlated topic vector inherits the advantages of Fisher vector. The contributions to the topics of visual words have been further employed by incorporating the Fisher kernel framework to indicate the differences among scenes. Combined with the deep convolutional neural network (CNN) features and Gibbs sampling solution, correlated topic vector shows great potential when processing large-scale and complex scene image data sets. Experiments on two scene image data sets demonstrate that correlated topic vector improves significantly the deep CNN features, and outperforms existing Fisher kernel-based features.

Charmless Hadronic B Decays into Vector, Axial Vector and Tensor Final States at BaBar

International Nuclear Information System (INIS)

Gandini, Paolo

2012-01-01

We present experimental measurements of branching fraction and longitudinal polarization fraction in charmless hadronic B decays into vector, axial vector and tensor final states with the final dataset of BABAR. Measurements of such kind of decays are a powerful tool both to test the Standard Model and search possible sources of new physics. In this document we present a short review of the last experimental results at BABAR concerning charmless quasi two-body decays in final states containing particles with spin 1 or spin 2 and different parities. This kind of decays has received considerable theoretical interest in the last few years and this particular attention has led to interesting experimental results at the current b-factories. In fact, the study of longitudinal polarization fraction f L in charmless B decays to vector vector (VV), vector axial-vector (VA) and axial-vector axial-vector (AA) mesons provides information on the underlying helicity structure of the decay mechanism. Naive helicity conservation arguments predict a dominant longitudinal polarization fraction f L ∼ 1 for both tree and penguin dominated decays and this pattern seems to be confirmed by tree-dominated B → ρρ and B + → (Omega)ρ + decays. Other penguin dominated decays, instead, show a different behavior: the measured value of f L ∼ 0.5 in B → φK* decays is in contrast with naive Standard Model (SM) calculations. Several solutions have been proposed such as the introduction of non-factorizable terms and penguin-annihilation amplitudes, while other explanations invoke new physics. New modes have been investigated to shed more light on the problem.

Test of Understanding of Vectors: A Reliable Multiple-Choice Vector Concept Test

Science.gov (United States)

Barniol, Pablo; Zavala, Genaro

2014-01-01

In this article we discuss the findings of our research on students' understanding of vector concepts in problems without physical context. First, we develop a complete taxonomy of the most frequent errors made by university students when learning vector concepts. This study is based on the results of several test administrations of open-ended…

Local Patch Vectors Encoded by Fisher Vectors for Image Classification

Directory of Open Access Journals (Sweden)

Shuangshuang Chen

2018-02-01

Full Text Available The objective of this work is image classification, whose purpose is to group images into corresponding semantic categories. Four contributions are made as follows: (i For computational simplicity and efficiency, we directly adopt raw image patch vectors as local descriptors encoded by Fisher vector (FV subsequently; (ii For obtaining representative local features within the FV encoding framework, we compare and analyze three typical sampling strategies: random sampling, saliency-based sampling and dense sampling; (iii In order to embed both global and local spatial information into local features, we construct an improved spatial geometry structure which shows good performance; (iv For reducing the storage and CPU costs of high dimensional vectors, we adopt a new feature selection method based on supervised mutual information (MI, which chooses features by an importance sorting algorithm. We report experimental results on dataset STL-10. It shows very promising performance with this simple and efficient framework compared to conventional methods.

Vector-Vector Scattering on the Lattice

Science.gov (United States)

Romero-López, Fernando; Urbach, Carsten; Rusetsky, Akaki

2018-03-01

In this work we present an extension of the LüScher formalism to include the interaction of particles with spin, focusing on the scattering of two vector particles. The derived formalism will be applied to Scalar QED in the Higgs Phase, where the U(1) gauge boson acquires mass.

Conformal Killing vectors in Robertson-Walker spacetimes

International Nuclear Information System (INIS)

Maartens, R.; Maharaj, S.d.

1986-01-01

It is well known that Robertson-Walker spacetimes admit a conformal Killingl vector normal to the spacelike homogeneous hypersurfaces. Because these spacetimes are conformally flat, there are a further eight conformal Killing vectors, which are neither normal nor tangent to the homogeneous hypersurfaces. The authors find these further conformal Killing vectors and the Lie algebra of the full G 15 of conformal motions. Conditions on the metric scale factor are determined which reduce some of the conformal Killing vectors to homothetic Killing vectors or Killing vectors, allowing one to regain in a unified way the known special geometries. The non-normal conformal Killing vectors provide a counter-example to show that conformal motions do not, in general, map a fluid flow conformally. These non-normal vectors are also used to find the general solution of the null geodesic equation and photon Liouville equation. (author)

A generalized nonlocal vector calculus

Science.gov (United States)

Alali, Bacim; Liu, Kuo; Gunzburger, Max

2015-10-01

A nonlocal vector calculus was introduced in Du et al. (Math Model Meth Appl Sci 23:493-540, 2013) that has proved useful for the analysis of the peridynamics model of nonlocal mechanics and nonlocal diffusion models. A formulation is developed that provides a more general setting for the nonlocal vector calculus that is independent of particular nonlocal models. It is shown that general nonlocal calculus operators are integral operators with specific integral kernels. General nonlocal calculus properties are developed, including nonlocal integration by parts formula and Green's identities. The nonlocal vector calculus introduced in Du et al. (Math Model Meth Appl Sci 23:493-540, 2013) is shown to be recoverable from the general formulation as a special example. This special nonlocal vector calculus is used to reformulate the peridynamics equation of motion in terms of the nonlocal gradient operator and its adjoint. A new example of nonlocal vector calculus operators is introduced, which shows the potential use of the general formulation for general nonlocal models.

Broad patterns in domestic vector-borne Trypanosoma cruzi transmission dynamics: synanthropic animals and vector control.

Science.gov (United States)

Peterson, Jennifer K; Bartsch, Sarah M; Lee, Bruce Y; Dobson, Andrew P

2015-10-22

Chagas disease (caused by Trypanosoma cruzi) is the most important neglected tropical disease (NTD) in Latin America, infecting an estimated 5.7 million people in the 21 countries where it is endemic. It is one of the NTDs targeted for control and elimination by the 2020 London Declaration goals, with the first goal being to interrupt intra-domiciliary vector-borne T. cruzi transmission. A key question in domestic T. cruzi transmission is the role that synanthropic animals play in T. cruzi transmission to humans. Here, we ask, (1) do synanthropic animals need to be targeted in Chagas disease prevention policies?, and (2) how does the presence of animals affect the efficacy of vector control? We developed a simple mathematical model to simulate domestic vector-borne T. cruzi transmission and to specifically examine the interaction between the presence of synanthropic animals and effects of vector control. We used the model to explore how the interactions between triatomine bugs, humans and animals impact the number and proportion of T. cruzi-infected bugs and humans. We then examined how T. cruzi dynamics change when control measures targeting vector abundance are introduced into the system. We found that the presence of synanthropic animals slows the speed of T. cruzi transmission to humans, and increases the sensitivity of T. cruzi transmission dynamics to vector control measures at comparable triatomine carrying capacities. However, T. cruzi transmission is amplified when triatomine carrying capacity increases with the abundance of syntathoropic hosts. Our results suggest that in domestic T. cruzi transmission scenarios where no vector control measures are in place, a reduction in synanthropic animals may slow T. cruzi transmission to humans, but it would not completely eliminate transmission. To reach the 2020 goal of interrupting intra-domiciliary T. cruzi transmission, it is critical to target vector populations. Additionally, where vector control measures

Spin information from vector-meson decay in photoproduction

International Nuclear Information System (INIS)

Kloet, W.M.; Chiang, W.; Tabakin, F.

1998-01-01

For the photoproduction of vector mesons, all single and double spin observables involving vector-meson two-body decays are defined consistently in the γN center-of-mass frame. These definitions yield a procedure for extracting physically meaningful single and double spin observables that are subject to known rules concerning their angle and energy evolution. As part of this analysis, we show that measuring the two-meson decay of a photo produced ρ or φ does not determine the vector meson's vector polarization, but only its tensor polarization. The vector meson decay into lepton pairs is also insensitive to the vector meson's vector polarization, unless one measures the spin of one of the leptons. Similar results are found for all double spin observables which involve observation of vector-meson decay. To access the vector meson's vector polarization, one therefore needs to either measure the spin of the decay leptons, make an analysis of the background interference effects, or relate the vector meson's vector polarization to other accessible spin observables. copyright 1998 The American Physical Society

[Effects of plant viruses on vector and non-vector herbivorous arthropods and their natural enemies: a mini review].

Science.gov (United States)

He, Xiao-Chan; Xu, Hong-Xing; Zhou, Xiao-Jun; Zheng, Xu-Song; Sun, Yu-Jian; Yang, Ya-Jun; Tian, Jun-Ce; Lü, Zhong-Xian

2014-05-01

Plant viruses transmitted by arthropods, as an important biotic factor, may not only directly affect the yield and quality of host plants, and development, physiological characteristics and ecological performances of their vector arthropods, but also directly or indirectly affect the non-vector herbivorous arthropods and their natural enemies in the same ecosystem, thereby causing influences to the whole agro-ecosystem. This paper reviewed the progress on the effects of plant viruses on herbivorous arthropods, including vector and non-vector, and their natural enemies, and on their ecological mechanisms to provide a reference for optimizing the management of vector and non-vector arthropod populations and sustainable control of plant viruses in agro-ecosystem.

Virus-Vectored Influenza Virus Vaccines

Science.gov (United States)

Tripp, Ralph A.; Tompkins, S. Mark

2014-01-01

Despite the availability of an inactivated vaccine that has been licensed for >50 years, the influenza virus continues to cause morbidity and mortality worldwide. Constant evolution of circulating influenza virus strains and the emergence of new strains diminishes the effectiveness of annual vaccines that rely on a match with circulating influenza strains. Thus, there is a continued need for new, efficacious vaccines conferring cross-clade protection to avoid the need for biannual reformulation of seasonal influenza vaccines. Recombinant virus-vectored vaccines are an appealing alternative to classical inactivated vaccines because virus vectors enable native expression of influenza antigens, even from virulent influenza viruses, while expressed in the context of the vector that can improve immunogenicity. In addition, a vectored vaccine often enables delivery of the vaccine to sites of inductive immunity such as the respiratory tract enabling protection from influenza virus infection. Moreover, the ability to readily manipulate virus vectors to produce novel influenza vaccines may provide the quickest path toward a universal vaccine protecting against all influenza viruses. This review will discuss experimental virus-vectored vaccines for use in humans, comparing them to licensed vaccines and the hurdles faced for licensure of these next-generation influenza virus vaccines. PMID:25105278

Vector Boson Scattering at High Mass

CERN Document Server

The ATLAS collaboration

2009-01-01

In the absence of a light Higgs boson, the mechanism of electroweak symmetry breaking will be best studied in processes of vector boson scattering at high mass. Various models predict resonances in this channel. Here, we investigate $WW $scalar and vector resonances, $WZ$ vector resonances and a $ZZ$ scalar resonance over a range of diboson centre-of-mass energies. Particular attention is paid to the application of forward jet tagging and to the reconstruction of dijet pairs with low opening angle resulting from the decay of highly boosted vector bosons. The performances of different jet algorithms are compared. We find that resonances in vector boson scattering can be discovered with a few tens of inverse femtobarns of integrated luminosity.

Symmetric vectors and algebraic classification

International Nuclear Information System (INIS)

Leibowitz, E.

1980-01-01

The concept of symmetric vector field in Riemannian manifolds, which arises in the study of relativistic cosmological models, is analyzed. Symmetric vectors are tied up with the algebraic properties of the manifold curvature. A procedure for generating a congruence of symmetric fields out of a given pair is outlined. The case of a three-dimensional manifold of constant curvature (''isotropic universe'') is studied in detail, with all its symmetric vector fields being explicitly constructed

Suplementação de N-acetilcisteína em pacientes infectados pelo HIV submetidos ao primeiro tratamento anti-retroviral: Avaliação do efeito sobre a carga viral, TNF-α, IL-6, IL-8, β2-microglobulina, IgA, IgG e IgM, haptoglobina e α1-glicoproteína ácida N-acetylcysteine supplementation of HIV-infected patients under the first anti-retroviral treatment: Evaluation of the effect on viral load, TNF-α, IL-6, IL-8, β2-microglobulin, IgA, IgG, IgM, haptoglobin and α1-acid glycoprotein

Directory of Open Access Journals (Sweden)

Aricio Treitinger

2002-03-01

Full Text Available Indivíduos infectados pelo vírus da imunodeficiência humana (HIV- 1 apresentam aumento progressivo da carga viral, da destruição do sistema de defesa imune celular e alterações imunológicas e inflamatórias, incluindo a elevação dos níveis séricos do fator de necrose tumoral alfa (TNF-α, interleucina 8 (IL-8, β2- microglobulina, IgA, IgG e IgM, haptoglobina e α1-glicoproteína ácida.O objetivo deste estudo foi avaliar os níveis séricos destes marcadores em indivíduos submetidos ao primeiro tratamento antiretroviral, suplementados ou não com N-acetilcisteína. Participaram deste estudo, duplo cego controlado por placebo, que teve a duração de 180 dias, 24 indivíduos que iniciaram a terapia antiretroviral O Grupo Estudo foi constituído por 11 indivíduos, que receberam suplementação de 600 mg/dia de Nacetilcisteína enquanto o Grupo Controle foi constituído por 13 indivíduo que receberam placebo. Os níveis dos marcadores avaliados foram determinados no dia anterior ao início do tratamento a que foram submetidos e após 60, 120 e 180 dias. Verificou-se diminuição significativa dos níveis de TNF-α (p=0,0001, IL-6 (p>0,05, IL-8 (p=0,0001, β2-microglobulina (p=0,0005, IgA (p=0,007, IgG (p=0,001, IgM (p=0,0001, haptoglobina (p=0,0001 e α1-glicoproteína ácida (p=0.012 em decorrência do tratamento anti-retroviral. A suplementação com N-acetilcisteína, na dose utilizada neste estudo, não teve efeitos aditivos ou sinérgicos sobre as variáveis analisadas. Em conclusão, a suplementação de pacientes HIV-positivos com 600 mg/dia de N-acetilcisteína não proporcionou benefícios adicionais àqueles decorrentes do tratamento anti-retroviral.Human immunodeficiency virus infection is associated with a progressive elevation of viral load and with a continuous destruction of the immune cellular defense system which is marked by immunological and inflammatory disorders characteristic of HIV-infected individuals. These

Induction of Type I Interferons by Therapeutic Nanoparticle-Based Vaccination Is Indispensable to Reinforce Cytotoxic CD8+ T Cell Responses During Chronic Retroviral Infection

Directory of Open Access Journals (Sweden)

Torben Knuschke

2018-04-01

Full Text Available T cell dysfunction and immunosuppression are characteristic for chronic viral infections and contribute to viral persistence. Overcoming these burdens is the goal of new therapeutic strategies to cure chronic infectious diseases. We recently described that therapeutic vaccination of chronic retrovirus infected mice with a calcium phosphate (CaP nanoparticle (NP-based vaccine carrier, functionalized with CpG and viral peptides is able to efficiently reactivate the CD8+ T cell response and improve the eradication of virus infected cells. However, the mechanisms underlying this effect were largely unclear. While type I interferons (IFNs I are considered to drive T cell exhaustion by persistent immune activation during chronic viral infection, we here describe an indispensable role of IFN I induced by therapeutic vaccination to efficiently reinforce cytotoxic CD8+ T cells (CTL and improve control of chronic retroviral infection. The induction of IFN I is CpG dependent and leads to significant IFN signaling indicated by upregulation of IFN stimulated genes. By vaccinating chronically retrovirus-infected mice lacking the IFN I receptor (IFNAR−/− or by blocking IFN I signaling in vivo during therapeutic vaccination, we demonstrate that IFN I signaling is necessary to drive full reactivation of CTLs. Surprisingly, we also identified an impaired suppressive capability of regulatory T cells in the presence of IFNα, which implicates an important role for vaccine-induced IFNα in the regulation of the T cell response during chronic retroviral infection. Our data suggest that inducing IFN I signaling in conjunction with the presentation of viral antigens can reactivate immune functions and reduce viral loads in chronic infections. Therefore, we propose CaP NPs as potential therapeutic tool to treat chronic infections.

[New strategy for RNA vectorization in mammalian cells. Use of a peptide vector].

Science.gov (United States)

Vidal, P; Morris, M C; Chaloin, L; Heitz, F; Divita, G

1997-04-01

A major barrier for gene delivery is the low permeability of nucleic acids to cellular membranes. The development of antisenses and gene therapy has focused mainly on improving methods of oligonucleotide or gene delivery to the cell. In this report we described a new strategy for RNA cell delivery, based on a short single peptide. This peptide vector is derived from both the fusion domain of the gp41 protein of HIV and the nuclear localization sequence of the SV40 large T antigen. This peptide vector localizes rapidly to the cytoplasm then to the nucleus of human fibroblasts (HS-68) within a few minutes and exhibits a high affinity for a single-stranded mRNA encoding the p66 subunit of the HIV-1 reverse transcriptase (in a 100 nM range). The peptide/RNA complex formation involves mainly electrostatic interactions between the basic residues of the peptide and the charges on the phosphate group of the RNA. In the presence of the peptide-vector fluorescently-labelled mRNA is delivered into the cytoplasm of mammalian cells (HS68 human fibroblasts) in less than 1 h with a relatively high efficiency (80%). This new concept based on a peptide-derived vector offers several advantages compared to other compounds commonly used in gene delivery. This vector is highly soluble and exhibits no cytotoxicity at the concentrations used for optimal gene delivery. This result clearly supports the fact that this peptide vector is a powerful tool and that it can be used widely, as much for laboratory research as for new applications and development in gene and/or antisense therapy.

Attenuated Vector Tomography -- An Approach to Image Flow Vector Fields with Doppler Ultrasonic Imaging

International Nuclear Information System (INIS)

Huang, Qiu; Peng, Qiyu; Huang, Bin; Cheryauka, Arvi; Gullberg, Grant T.

2008-01-01

The measurement of flow obtained using continuous wave Doppler ultrasound is formulated as a directional projection of a flow vector field. When a continuous ultrasound wave bounces against a flowing particle, a signal is backscattered. This signal obtains a Doppler frequency shift proportional to the speed of the particle along the ultrasound beam. This occurs for each particle along the beam, giving rise to a Doppler velocity spectrum. The first moment of the spectrum provides the directional projection of the flow along the ultrasound beam. Signals reflected from points further away from the detector will have lower amplitude than signals reflected from points closer to the detector. The effect is very much akin to that modeled by the attenuated Radon transform in emission computed tomography.A least-squares method was adopted to reconstruct a 2D vector field from directional projection measurements. Attenuated projections of only the longitudinal projections of the vector field were simulated. The components of the vector field were reconstructed using the gradient algorithm to minimize a least-squares criterion. This result was compared with the reconstruction of longitudinal projections of the vector field without attenuation. If attenuation is known, the algorithm was able to accurately reconstruct both components of the full vector field from only one set of directional projection measurements. A better reconstruction was obtained with attenuation than without attenuation implying that attenuation provides important information for the reconstruction of flow vector fields.This confirms previous work where we showed that knowledge of the attenuation distribution helps in the reconstruction of MRI diffusion tensor fields from fewer than the required measurements. In the application of ultrasound the attenuation distribution is obtained with pulse wave transmission computed tomography and flow information is obtained with continuous wave Doppler

40 CFR 503.33 - Vector attraction reduction.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Vector attraction reduction. 503.33... STANDARDS FOR THE USE OR DISPOSAL OF SEWAGE SLUDGE Pathogens and Vector Attraction Reduction § 503.33 Vector attraction reduction. (a)(1) One of the vector attraction reduction requirements in § 503.33 (b)(1) through...

Vector Boson Scattering at High Mass

CERN Document Server

Sherwood, P

2009-01-01

In the absence of a light Higgs boson, the mechanism of electroweak symmetry breaking will be best studied in processes of vector boson scattering at high mass. Various models predict resonances in this channel. Here, we investigate W W scalar and vector resonances, W Z vector resonances and a Z Z scalar resonance over a range of diboson centre-of-mass energies. Particular attention is paid to the application reconstruction of dijet pairs with low opening angle resulting from the decay of highly boosted vector bosons.

Optimality Conditions in Vector Optimization

CERN Document Server

Jiménez, Manuel Arana; Lizana, Antonio Rufián

2011-01-01

Vector optimization is continuously needed in several science fields, particularly in economy, business, engineering, physics and mathematics. The evolution of these fields depends, in part, on the improvements in vector optimization in mathematical programming. The aim of this Ebook is to present the latest developments in vector optimization. The contributions have been written by some of the most eminent researchers in this field of mathematical programming. The Ebook is considered essential for researchers and students in this field.

Multineuronal vectorization is more efficient than time-segmental vectorization for information extraction from neuronal activities in the inferior temporal cortex.

Science.gov (United States)

Kaneko, Hidekazu; Tamura, Hiroshi; Tate, Shunta; Kawashima, Takahiro; Suzuki, Shinya S; Fujita, Ichiro

2010-08-01

In order for patients with disabilities to control assistive devices with their own neural activity, multineuronal spike trains must be efficiently decoded because only limited computational resources can be used to generate prosthetic control signals in portable real-time applications. In this study, we compare the abilities of two vectorizing procedures (multineuronal and time-segmental) to extract information from spike trains during the same total neuron-seconds. In the multineuronal vectorizing procedure, we defined a response vector whose components represented the spike counts of one to five neurons. In the time-segmental vectorizing procedure, a response vector consisted of components representing a neuron's spike counts for one to five time-segment(s) of a response period of 1 s. Spike trains were recorded from neurons in the inferior temporal cortex of monkeys presented with visual stimuli. We examined whether the amount of information of the visual stimuli carried by these neurons differed between the two vectorizing procedures. The amount of information calculated with the multineuronal vectorizing procedure, but not the time-segmental vectorizing procedure, significantly increased with the dimensions of the response vector. We conclude that the multineuronal vectorizing procedure is superior to the time-segmental vectorizing procedure in efficiently extracting information from neuronal signals. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Adenoviral vector immunity: its implications and circumvention strategies.

Science.gov (United States)

Ahi, Yadvinder S; Bangari, Dinesh S; Mittal, Suresh K

2011-08-01

Adenoviral (Ad) vectors have emerged as a promising gene delivery platform for a variety of therapeutic and vaccine purposes during last two decades. However, the presence of preexisting Ad immunity and the rapid development of Ad vector immunity still pose significant challenges to the clinical use of these vectors. Innate inflammatory response following Ad vector administration may lead to systemic toxicity, drastically limit vector transduction efficiency and significantly abbreviate the duration of transgene expression. Currently, a number of approaches are being extensively pursued to overcome these drawbacks by strategies that target either the host or the Ad vector. In addition, significant progress has been made in the development of novel Ad vectors based on less prevalent human Ad serotypes and nonhuman Ad. This review provides an update on our current understanding of immune responses to Ad vectors and delineates various approaches for eluding Ad vector immunity. Approaches targeting the host and those targeting the vector are discussed in light of their promises and limitations.

A Subdivision-Based Representation for Vector Image Editing.

Science.gov (United States)

Liao, Zicheng; Hoppe, Hugues; Forsyth, David; Yu, Yizhou

2012-11-01

Vector graphics has been employed in a wide variety of applications due to its scalability and editability. Editability is a high priority for artists and designers who wish to produce vector-based graphical content with user interaction. In this paper, we introduce a new vector image representation based on piecewise smooth subdivision surfaces, which is a simple, unified and flexible framework that supports a variety of operations, including shape editing, color editing, image stylization, and vector image processing. These operations effectively create novel vector graphics by reusing and altering existing image vectorization results. Because image vectorization yields an abstraction of the original raster image, controlling the level of detail of this abstraction is highly desirable. To this end, we design a feature-oriented vector image pyramid that offers multiple levels of abstraction simultaneously. Our new vector image representation can be rasterized efficiently using GPU-accelerated subdivision. Experiments indicate that our vector image representation achieves high visual quality and better supports editing operations than existing representations.

Generalized Selection Weighted Vector Filters

Directory of Open Access Journals (Sweden)

Rastislav Lukac

2004-09-01

Full Text Available This paper introduces a class of nonlinear multichannel filters capable of removing impulsive noise in color images. The here-proposed generalized selection weighted vector filter class constitutes a powerful filtering framework for multichannel signal processing. Previously defined multichannel filters such as vector median filter, basic vector directional filter, directional-distance filter, weighted vector median filters, and weighted vector directional filters are treated from a global viewpoint using the proposed framework. Robust order-statistic concepts and increased degree of freedom in filter design make the proposed method attractive for a variety of applications. Introduced multichannel sigmoidal adaptation of the filter parameters and its modifications allow to accommodate the filter parameters to varying signal and noise statistics. Simulation studies reported in this paper indicate that the proposed filter class is computationally attractive, yields excellent performance, and is able to preserve fine details and color information while efficiently suppressing impulsive noise. This paper is an extended version of the paper by Lukac et al. presented at the 2003 IEEE-EURASIP Workshop on Nonlinear Signal and Image Processing (NSIP '03 in Grado, Italy.

Production of lentiviral vectors

Directory of Open Access Journals (Sweden)

Otto-Wilhelm Merten

2016-01-01

Full Text Available Lentiviral vectors (LV have seen considerably increase in use as gene therapy vectors for the treatment of acquired and inherited diseases. This review presents the state of the art of the production of these vectors with particular emphasis on their large-scale production for clinical purposes. In contrast to oncoretroviral vectors, which are produced using stable producer cell lines, clinical-grade LV are in most of the cases produced by transient transfection of 293 or 293T cells grown in cell factories. However, more recent developments, also, tend to use hollow fiber reactor, suspension culture processes, and the implementation of stable producer cell lines. As is customary for the biotech industry, rather sophisticated downstream processing protocols have been established to remove any undesirable process-derived contaminant, such as plasmid or host cell DNA or host cell proteins. This review compares published large-scale production and purification processes of LV and presents their process performances. Furthermore, developments in the domain of stable cell lines and their way to the use of production vehicles of clinical material will be presented.

Inverse Operation of Four-dimensional Vector Matrix

OpenAIRE

H J Bao; A J Sang; H X Chen

2011-01-01

This is a new series of study to define and prove multidimensional vector matrix mathematics, which includes four-dimensional vector matrix determinant, four-dimensional vector matrix inverse and related properties. There are innovative concepts of multi-dimensional vector matrix mathematics created by authors with numerous applications in engineering, math, video conferencing, 3D TV, and other fields.

The second chance story of HIV-1 DNA: Unintegrated? Not a problem!

Directory of Open Access Journals (Sweden)

Wu Yuntao

2008-07-01

Full Text Available Abstract Accumulation of high levels of unintegrated viral DNA is a common feature of retroviral infection. It was recently discovered that coinfection of cells with integrated and unintegrated HIV-1 can result in complementation, allowing viral replication in the absence of integration. This new mode of HIV-1 replication has numerous implications for the function of unintegrated viral DNA and its application as a therapeutic vector.

Stemcell Information: SKIP000176 [SKIP Stemcell Database[Archive

Lifescience Database Archive (English)

Full Text Available male Black Black -- No Apparently healthy iPSCs from APPARENTLY HEALTHY FETAL lung fibroblast cell culture (GM06112) 健常胎児肺線維芽細胞... SKIP000176 ... Lung Fibroblast 肺線維芽細胞 Normal GM23413 GM23413 ... 0-9 Fe...(GM06112)由来iPS細胞株 human ES-like -- Retrovirus Oct4, Sox2, Klf, c-Myc, retroviral vectors

Multiscale vector fields for image pattern recognition

Science.gov (United States)

Low, Kah-Chan; Coggins, James M.

1990-01-01

A uniform processing framework for low-level vision computing in which a bank of spatial filters maps the image intensity structure at each pixel into an abstract feature space is proposed. Some properties of the filters and the feature space are described. Local orientation is measured by a vector sum in the feature space as follows: each filter's preferred orientation along with the strength of the filter's output determine the orientation and the length of a vector in the feature space; the vectors for all filters are summed to yield a resultant vector for a particular pixel and scale. The orientation of the resultant vector indicates the local orientation, and the magnitude of the vector indicates the strength of the local orientation preference. Limitations of the vector sum method are discussed. Investigations show that the processing framework provides a useful, redundant representation of image structure across orientation and scale.

Vector control of induction machines

CERN Document Server

Robyns, Benoit

2012-01-01

After a brief introduction to the main law of physics and fundamental concepts inherent in electromechanical conversion, ""Vector Control of Induction Machines"" introduces the standard mathematical models for induction machines - whichever rotor technology is used - as well as several squirrel-cage induction machine vector-control strategies. The use of causal ordering graphs allows systematization of the design stage, as well as standardization of the structure of control devices. ""Vector Control of Induction Machines"" suggests a unique approach aimed at reducing parameter sensitivity for

Viral vector-based influenza vaccines

Science.gov (United States)

de Vries, Rory D.; Rimmelzwaan, Guus F.

2016-01-01

ABSTRACT Antigenic drift of seasonal influenza viruses and the occasional introduction of influenza viruses of novel subtypes into the human population complicate the timely production of effective vaccines that antigenically match the virus strains that cause epidemic or pandemic outbreaks. The development of game-changing vaccines that induce broadly protective immunity against a wide variety of influenza viruses is an unmet need, in which recombinant viral vectors may provide. Use of viral vectors allows the delivery of any influenza virus antigen, or derivative thereof, to the immune system, resulting in the optimal induction of virus-specific B- and T-cell responses against this antigen of choice. This systematic review discusses results obtained with vectored influenza virus vaccines and advantages and disadvantages of the currently available viral vectors. PMID:27455345

Integrated optic vector-matrix multiplier

Science.gov (United States)

Watts, Michael R [Albuquerque, NM

2011-09-27

A vector-matrix multiplier is disclosed which uses N different wavelengths of light that are modulated with amplitudes representing elements of an N.times.1 vector and combined to form an input wavelength-division multiplexed (WDM) light stream. The input WDM light stream is split into N streamlets from which each wavelength of the light is individually coupled out and modulated for a second time using an input signal representing elements of an M.times.N matrix, and is then coupled into an output waveguide for each streamlet to form an output WDM light stream which is detected to generate a product of the vector and matrix. The vector-matrix multiplier can be formed as an integrated optical circuit using either waveguide amplitude modulators or ring resonator amplitude modulators.

3D vector flow imaging

DEFF Research Database (Denmark)

Pihl, Michael Johannes

The main purpose of this PhD project is to develop an ultrasonic method for 3D vector flow imaging. The motivation is to advance the field of velocity estimation in ultrasound, which plays an important role in the clinic. The velocity of blood has components in all three spatial dimensions, yet...... are (vx, vy, vz) = (-0.03, 95, 1.0) ± (9, 6, 1) cm/s compared with the expected (0, 96, 0) cm/s. Afterwards, 3D vector flow images from a cross-sectional plane of the vessel are presented. The out of plane velocities exhibit the expected 2D circular-symmetric parabolic shape. The experimental results...... verify that the 3D TO method estimates the complete 3D velocity vectors, and that the method is suitable for 3D vector flow imaging....

Problems and worked solutions in vector analysis

CERN Document Server

Shorter, LR

2014-01-01

""A handy book like this,"" noted The Mathematical Gazette, ""will fill a great want."" Devoted to fully worked out examples, this unique text constitutes a self-contained introductory course in vector analysis for undergraduate and graduate students of applied mathematics.Opening chapters define vector addition and subtraction, show how to resolve and determine the direction of two or more vectors, and explain systems of coordinates, vector equations of a plane and straight line, relative velocity and acceleration, and infinitely small vectors. The following chapters deal with scalar and vect

Gauge structure of neutral-vector field theory. [Massive vector fields, massless limits

Energy Technology Data Exchange (ETDEWEB)

Kubo, R; Yokoyama, [Hiroshima univ., Takehara (Japan). Research Inst. for Theoretical Physics

1975-03-01

General aspects of gauge structure of neutral-vector field theory are investigated from an extended standpoint, where massive vector fields are treated in a form corresponding to the electromagnetic fields in a general gauge formalism reported previously. All results obtained are shown to have unique massless limits. It is shown that a generalized q-number gauge transformation for fields makes the theory invariant in cooperation with a simultaneous transformation for relevant gauge parameters. A method of differentiation with respect to a gauge variable is found to clarify some essential features of the gauge structure. Two possible types of gauge structure also emerge correspondingly to the massless case. A neutral-vector field theory proposed in a preceding paper is included in the present framework as the most preferable case.

Matrix vector analysis

CERN Document Server

Eisenman, Richard L

2005-01-01

This outstanding text and reference applies matrix ideas to vector methods, using physical ideas to illustrate and motivate mathematical concepts but employing a mathematical continuity of development rather than a physical approach. The author, who taught at the U.S. Air Force Academy, dispenses with the artificial barrier between vectors and matrices--and more generally, between pure and applied mathematics.Motivated examples introduce each idea, with interpretations of physical, algebraic, and geometric contexts, in addition to generalizations to theorems that reflect the essential structur

Declining Prevalence of Disease Vectors Under Climate Change

Science.gov (United States)

Escobar, Luis E.; Romero-Alvarez, Daniel; Leon, Renato; Lepe-Lopez, Manuel A.; Craft, Meggan E.; Borbor-Cordova, Mercy J.; Svenning, Jens-Christian

2016-12-01

More than half of the world population is at risk of vector-borne diseases including dengue fever, chikungunya, zika, yellow fever, leishmaniasis, chagas disease, and malaria, with highest incidences in tropical regions. In Ecuador, vector-borne diseases are present from coastal and Amazonian regions to the Andes Mountains; however, a detailed characterization of the distribution of their vectors has never been carried out. We estimate the distribution of 14 vectors of the above vector-borne diseases under present-day and future climates. Our results consistently suggest that climate warming is likely threatening some vector species with extinction, locally or completely. These results suggest that climate change could reduce the burden of specific vector species. Other vector species are likely to shift and constrain their geographic range to the highlands in Ecuador potentially affecting novel areas and populations. These forecasts show the need for development of early prevention strategies for vector species currently absent in areas projected as suitable under future climate conditions. Informed interventions could reduce the risk of human exposure to vector species with distributional shifts, in response to current and future climate changes. Based on the mixed effects of future climate on human exposure to disease vectors, we argue that research on vector-borne diseases should be cross-scale and include climatic, demographic, and landscape factors, as well as forces facilitating disease transmission at fine scales.

Vector boson scattering at CLIC

Energy Technology Data Exchange (ETDEWEB)

Kilian, Wolfgang; Fleper, Christian [Department Physik, Universitaet Siegen, 57068 Siegen (Germany); Reuter, Juergen [DESY Theory Group, 22603 Hamburg (Germany); Sekulla, Marco [Institut fuer Theoretische Physik, Karlsruher Institut fuer Technologie, 76131 Karlsruhe (Germany)

2016-07-01

Linear colliders operating in a range of multiple TeV are able to investigate the details of vector boson scattering and electroweak symmetry breaking. We calculate cross sections with the Monte Carlo generator WHIZARD for vector boson scattering processes at the future linear e{sup +} e{sup -} collider CLIC. By finding suitable cuts, the vector boson scattering signal processes are isolated from the background. Finally, we are able to determine exclusion sensitivities on the non-Standard Model parameters of the relevant dimension eight operators.

Hematopoiesis stimulation test by interleukin 1α gene transfer in the Cynomolgus macaque: application to secondary medullary aplasia from an accidental irradiation

International Nuclear Information System (INIS)

De Revel, Th.

2002-12-01

After a description of the context of medullary aplasia (haematological radiobiology, radiation acute syndrome, therapeutic care), and an overview of knowledge about the interleukin-1 and medullary stroma cells, this research thesis aims at investigating therapeutic alternatives for radio-accidental aplasia. More precisely, it aims at defining means to get cytokines which are efficient for haematopoiesis. Interleukin-1 is chosen for its properties and tests are performed on a macaque with two approaches for gene transfer: an ex vivo transfer by retroviral vector enabling an integration in the target cell genome, and an in situ transfer by adeno-viral vector directly applied in the animal osseous medulla

Decays of the vector glueball

Science.gov (United States)

Giacosa, Francesco; Sammet, Julia; Janowski, Stanislaus

2017-06-01

We calculate two- and three-body decays of the (lightest) vector glueball into (pseudo)scalar, (axial-)vector, as well as pseudovector and excited vector mesons in the framework of a model of QCD. While absolute values of widths cannot be predicted because the corresponding coupling constants are unknown, some interesting branching ratios can be evaluated by setting the mass of the yet hypothetical vector glueball to 3.8 GeV as predicted by quenched lattice QCD. We find that the decay mode ω π π should be one of the largest (both through the decay chain O →b1π →ω π π and through the direct coupling O →ω π π ). Similarly, the (direct and indirect) decay into π K K*(892 ) is sizable. Moreover, the decays into ρ π and K*(892 )K are, although subleading, possible and could play a role in explaining the ρ π puzzle of the charmonium state ψ (2 S ) thanks to a (small) mixing with the vector glueball. The vector glueball can be directly formed at the ongoing BESIII experiment as well as at the future PANDA experiment at the FAIR facility. If the width is sufficiently small (≲100 MeV ) it should not escape future detection. It should be stressed that the employed model is based on some inputs and simplifying assumptions: the value of glueball mass (at present, the quenched lattice value is used), the lack of mixing of the glueball with other quarkonium states, and the use of few interaction terms. It then represents a first step toward the identification of the main decay channels of the vector glueball, but shall be improved when corresponding experimental candidates and/or new lattice results will be available.

Virtual-vector-based space vector pulse width modulation of the DC-AC multilevel-clamped multilevel converter (MLC²)

DEFF Research Database (Denmark)

Rodriguez, Pedro; Busquets-Monge, Sergio; Blaabjerg, Frede

2011-01-01

This work presents the development of the space vector pulse width modulation (SVPWM) of a new multi-level converter topology. First, the proposed converter and its natural space vector diagram are presented. Secondly, a modified space vector diagram based on the virtual-vectors technique is show...

Cost-effectiveness of anti-retroviral therapy at a district hospital in southern Ethiopia

Directory of Open Access Journals (Sweden)

Robberstad Bjarne

2009-07-01

Full Text Available Abstract Background As the resource implications of expanding anti-retroviral therapy (ART are likely to be large, there is a need to explore its cost-effectiveness. So far, there is no such information available from Ethiopia. Objective To assess the cost-effectiveness of ART for routine clinical practice in a district hospital setting in Ethiopia. Methods We estimated the unit cost of HIV-related care from the 2004/5 fiscal year expenditure of Arba Minch Hospital in southern Ethiopia. We estimated outpatient and inpatient service use from HIV-infected patients who received care and treatment at the hospital between January 2003 and March 2006. We measured the health effect as life years gained (LYG for patients receiving ART compared with those not receiving such treatment. The study adopted a health care provider perspective and included both direct and overhead costs. We used Markov model to estimate the lifetime costs, health benefits and cost-effectiveness of ART. Findings ART yielded an undiscounted 9.4 years expected survival, and resulted in 7.1 extra LYG compared to patients not receiving ART. The lifetime incremental cost is US$2,215 and the undiscounted incremental cost per LYG is US$314. When discounted at 3%, the additional LYG decreases to 5.5 years and the incremental cost per LYG increases to US$325. Conclusion The undiscounted and discounted incremental costs per LYG from introducing ART were less than the per capita GDP threshold at the base year. Thus, ART could be regarded as cost-effective in a district hospital setting in Ethiopia.

Image Coding Based on Address Vector Quantization.

Science.gov (United States)

Feng, Yushu

Image coding is finding increased application in teleconferencing, archiving, and remote sensing. This thesis investigates the potential of Vector Quantization (VQ), a relatively new source coding technique, for compression of monochromatic and color images. Extensions of the Vector Quantization technique to the Address Vector Quantization method have been investigated. In Vector Quantization, the image data to be encoded are first processed to yield a set of vectors. A codeword from the codebook which best matches the input image vector is then selected. Compression is achieved by replacing the image vector with the index of the code-word which produced the best match, the index is sent to the channel. Reconstruction of the image is done by using a table lookup technique, where the label is simply used as an address for a table containing the representative vectors. A code-book of representative vectors (codewords) is generated using an iterative clustering algorithm such as K-means, or the generalized Lloyd algorithm. A review of different Vector Quantization techniques are given in chapter 1. Chapter 2 gives an overview of codebook design methods including the Kohonen neural network to design codebook. During the encoding process, the correlation of the address is considered and Address Vector Quantization is developed for color image and monochrome image coding. Address VQ which includes static and dynamic processes is introduced in chapter 3. In order to overcome the problems in Hierarchical VQ, Multi-layer Address Vector Quantization is proposed in chapter 4. This approach gives the same performance as that of the normal VQ scheme but the bit rate is about 1/2 to 1/3 as that of the normal VQ method. In chapter 5, a Dynamic Finite State VQ based on a probability transition matrix to select the best subcodebook to encode the image is developed. In chapter 6, a new adaptive vector quantization scheme, suitable for color video coding, called "A Self -Organizing

Estimation of pure autoregressive vector models for revenue series ...

African Journals Online (AJOL)

This paper aims at applying multivariate approach to Box and Jenkins univariate time series modeling to three vector series. General Autoregressive Vector Models with time varying coefficients are estimated. The first vector is a response vector, while others are predictor vectors. By matrix expansion each vector, whether ...

On the Witt vector Frobenius

DEFF Research Database (Denmark)

Davis, Christopher James; Kedlaya, Kiran

2014-01-01

We study the kernel and cokernel of the Frobenius map on the p-typical Witt vectors of a commutative ring, not necessarily of characteristic p. We give many equivalent conditions to surjectivity of the Frobenius map on both finite and infinite length Witt vectors. In particular, surjectivity...... on finite Witt vectors turns out to be stable under certain integral extensions; this provides a clean formulation of a strong generalization of Faltings’s almost purity theorem from p-adic Hodge theory, incorporating recent improvements by Kedlaya–Liu and by Scholze....

Design and Potential of Non-Integrating Lentiviral Vectors

Directory of Open Access Journals (Sweden)

Aaron Shaw

2014-01-01

Full Text Available Lentiviral vectors have demonstrated promising results in clinical trials that target cells of the hematopoietic system. For these applications, they are the vectors of choice since they provide stable integration into cells that will undergo extensive expansion in vivo. Unfortunately, integration can have unintended consequences including dysregulated cell growth. Therefore, lentiviral vectors that do not integrate are predicted to have a safer profile compared to integrating vectors and should be considered for applications where transient expression is required or for sustained episomal expression such as in quiescent cells. In this review, the system for generating lentiviral vectors will be described and used to illustrate how alterations in the viral integrase or vector Long Terminal Repeats have been used to generate vectors that lack the ability to integrate. In addition to their safety advantages, these non-integrating lentiviral vectors can be used when persistent expression would have adverse consequences. Vectors are currently in development for use in vaccinations, cancer therapy, site-directed gene insertions, gene disruption strategies, and cell reprogramming. Preclinical work will be described that illustrates the potential of this unique vector system in human gene therapy.

Who is accessing public-sector anti-retroviral treatment in the Free State, South Africa? An exploratory study of the first three years of programme implementation

Directory of Open Access Journals (Sweden)

Booysen Frederik

2010-07-01

Full Text Available Abstract Background Although South Africa has the largest public-sector anti-retroviral treatment (ART programme in the world, anti-retroviral coverage in adults was only 40.2% in 2008. However, longitudinal studies of who is accessing the South African public-sector ART programme are scarce. This study therefore had one main research question: who is accessing public-sector ART in the Free State Province, South Africa? The study aimed to extend the current literature by investigating, in a quantitative manner and using a longitudinal study design, the participants enrolled in the public-sector ART programme in the period 2004-2006 in the Free State Province of South Africa. Methods Differences in the demographic (age, sex, population group and marital status socio-economic (education, income, neo-material indicators, geographic (travel costs, relocation for ART, and medical characteristics (CD4, viral load, time since first diagnosis, treatment status among 912 patients enrolled in the Free State public-sector ART programme between 2004 and 2006 were assessed with one-way analysis of variance, Bonferroni post-hoc analysis, and cross tabulations with the chi square test. Results The patients accessing treatment tended to be female (71.1% and unemployed (83.4%. However, although relatively poor, those most likely to access ART services were not the most impoverished patients. The proportion of female patients increased (P P P P P Conclusions Our analysis showed significant changes in the demographic, socio-economic, geographic, and medical characteristics of the patients during the first three years of the programme. Knowledge of the characteristics of these patients can assist policy makers in developing measures to retain them in care. The information reported here can also be usefully applied to target patient groups that are currently not reached in the implementation of the ART programme.

Archimedeanization of ordered vector spaces

OpenAIRE

Emelyanov, Eduard Yu.

2014-01-01

In the case of an ordered vector space with an order unit, the Archimedeanization method has been developed recently by V.I Paulsen and M. Tomforde. We present a general version of the Archimedeanization which covers arbitrary ordered vector spaces.

How random is a random vector?

International Nuclear Information System (INIS)

Eliazar, Iddo

2015-01-01

Over 80 years ago Samuel Wilks proposed that the “generalized variance” of a random vector is the determinant of its covariance matrix. To date, the notion and use of the generalized variance is confined only to very specific niches in statistics. In this paper we establish that the “Wilks standard deviation” –the square root of the generalized variance–is indeed the standard deviation of a random vector. We further establish that the “uncorrelation index” –a derivative of the Wilks standard deviation–is a measure of the overall correlation between the components of a random vector. Both the Wilks standard deviation and the uncorrelation index are, respectively, special cases of two general notions that we introduce: “randomness measures” and “independence indices” of random vectors. In turn, these general notions give rise to “randomness diagrams”—tangible planar visualizations that answer the question: How random is a random vector? The notion of “independence indices” yields a novel measure of correlation for Lévy laws. In general, the concepts and results presented in this paper are applicable to any field of science and engineering with random-vectors empirical data.

How random is a random vector?

Science.gov (United States)

Eliazar, Iddo

2015-12-01

Over 80 years ago Samuel Wilks proposed that the "generalized variance" of a random vector is the determinant of its covariance matrix. To date, the notion and use of the generalized variance is confined only to very specific niches in statistics. In this paper we establish that the "Wilks standard deviation" -the square root of the generalized variance-is indeed the standard deviation of a random vector. We further establish that the "uncorrelation index" -a derivative of the Wilks standard deviation-is a measure of the overall correlation between the components of a random vector. Both the Wilks standard deviation and the uncorrelation index are, respectively, special cases of two general notions that we introduce: "randomness measures" and "independence indices" of random vectors. In turn, these general notions give rise to "randomness diagrams"-tangible planar visualizations that answer the question: How random is a random vector? The notion of "independence indices" yields a novel measure of correlation for Lévy laws. In general, the concepts and results presented in this paper are applicable to any field of science and engineering with random-vectors empirical data.

Projection correlation between two random vectors.

Science.gov (United States)

Zhu, Liping; Xu, Kai; Li, Runze; Zhong, Wei

2017-12-01

We propose the use of projection correlation to characterize dependence between two random vectors. Projection correlation has several appealing properties. It equals zero if and only if the two random vectors are independent, it is not sensitive to the dimensions of the two random vectors, it is invariant with respect to the group of orthogonal transformations, and its estimation is free of tuning parameters and does not require moment conditions on the random vectors. We show that the sample estimate of the projection correction is [Formula: see text]-consistent if the two random vectors are independent and root-[Formula: see text]-consistent otherwise. Monte Carlo simulation studies indicate that the projection correlation has higher power than the distance correlation and the ranks of distances in tests of independence, especially when the dimensions are relatively large or the moment conditions required by the distance correlation are violated.

Simplified Representation of Vector Fields

NARCIS (Netherlands)

Telea, Alexandru; Wijk, Jarke J. van

1999-01-01

Vector field visualization remains a difficult task. Although many local and global visualization methods for vector fields such as flow data exist, they usually require extensive user experience on setting the visualization parameters in order to produce images communicating the desired insight. We

Problems of vector Lagrangians in field theories

International Nuclear Information System (INIS)

Krivsky, I.Yu.; Simulik, V.M.

1997-01-01

A vector Lagrange approach to the Dirac spinor field and the relationship between the vector Lagrangians for the spinor and electromagnetic fields are considered. A vector Lagrange approach for the system of interacting electromagnetic B=(B μ υ)=(E-bar,H-bar) and spinor Ψ fields is constructed. New Lagrangians (scalar and vector) for electromagnetic field in terms of field strengths are found. The foundations of two new QED models are formulated

The endogenous retroviral locus ERVWE1 is a bona fide gene involved in hominoid placental physiology

Science.gov (United States)

Mallet, François; Bouton, Olivier; Prudhomme, Sarah; Cheynet, Valérie; Oriol, Guy; Bonnaud, Bertrand; Lucotte, Gérard; Duret, Laurent; Mandrand, Bernard

2004-01-01

The definitive demonstration of a role for a recently acquired gene is a difficult task, requiring exhaustive genetic investigations and functional analysis. The situation is indeed much more complicated when facing multicopy gene families, because most or portions of the gene are conserved among the hundred copies of the family. This is the case for the ERVWE1 locus of the human endogenous retrovirus W family (HERV-W), which encodes an envelope glycoprotein (syncytin) likely involved in trophoblast differentiation. Here we describe, in 155 individuals, the positional conservation of this locus and the preservation of the envelope ORF. Sequencing of the critical elements of the ERVWE1 provirus showed a striking conservation among the 48 alleles of 24 individuals, including the LTR elements involved in the transcriptional machinery, the splice sites involved in the maturation of subgenomic Env mRNA, and the Env ORF. The functionality and tissue specificity of the 5′ LTR were demonstrated, as well as the fusogenic activity of the envelope polymorphic variants. Such functions were also shown to be preserved in the orthologous loci isolated from chimpanzee, gorilla, orangutan, and gibbon. This functional preservation among humans and during evolution strongly argued for the involvement of this recently acquired retroviral envelope glycoprotein in hominoid placental physiology. PMID:14757826

Effective SIMD Vectorization for Intel Xeon Phi Coprocessors

OpenAIRE

Tian, Xinmin; Saito, Hideki; Preis, Serguei V.; Garcia, Eric N.; Kozhukhov, Sergey S.; Masten, Matt; Cherkasov, Aleksei G.; Panchenko, Nikolay

2015-01-01

Efficiently exploiting SIMD vector units is one of the most important aspects in achieving high performance of the application code running on Intel Xeon Phi coprocessors. In this paper, we present several effective SIMD vectorization techniques such as less-than-full-vector loop vectorization, Intel MIC specific alignment optimization, and small matrix transpose/multiplication 2D vectorization implemented in the Intel C/C++ and Fortran production compilers for Intel Xeon Phi coprocessors. A ...

Specific in vitro cleavage of Mason-Pfizer monkey virus capsid protein: evidence for a potential role of retroviral protease in early stages of infection

International Nuclear Information System (INIS)

Rumlova, Michaela; Ruml, Tomas; Pohl, Jan; Pichova, Iva

2003-01-01

Processing of Gag polyproteins by viral protease (PR) leads to reorganization of immature retroviral particles and formation of a ribonucleoprotein core. In some retroviruses, such as HIV and RSV, cleavage of a spacer peptide separating capsid and nucleocapsid proteins is essential for the core formation. We show here that no similar spacer peptide is present in the capsid-nucleocapsid (CA-NC) region of Mason-Pfizer monkey virus (M-PMV) and that the CA protein is cleaved in vitro by the PR within the major homology region (MHR) and the NC protein in several sites at the N-terminus. The CA cleavage product was also identified shortly after penetration of M-PMV into COS cells, suggesting that the protease-catalyzed cleavage is involved in core disintegration

Vectors of rickettsiae in Africa.

Science.gov (United States)

Bitam, Idir

2012-12-01

Vector-borne diseases are caused by parasites, bacteria, or viruses transmitted by the bites of hematophagous arthropods. In Africa, there has been a recent emergence of new diseases and the re-emergence of existing diseases, usually with changes in disease epidemiology (e.g., geographical distribution, prevalence, and pathogenicity). In Africa, rickettsioses are recognized as important emerging vector-borne infections in humans. Rickettsial diseases are transmitted by different types of arthropods, ticks, fleas, lice, and mites. This review will examine the roles of these different arthropod vectors and their geographical distributions. Copyright © 2012 Elsevier GmbH. All rights reserved.

Modeling vector nonlinear time series using POLYMARS

NARCIS (Netherlands)

de Gooijer, J.G.; Ray, B.K.

2003-01-01

A modified multivariate adaptive regression splines method for modeling vector nonlinear time series is investigated. The method results in models that can capture certain types of vector self-exciting threshold autoregressive behavior, as well as provide good predictions for more general vector

Support vector machines applications

CERN Document Server

Guo, Guodong

2014-01-01

Support vector machines (SVM) have both a solid mathematical background and good performance in practical applications. This book focuses on the recent advances and applications of the SVM in different areas, such as image processing, medical practice, computer vision, pattern recognition, machine learning, applied statistics, business intelligence, and artificial intelligence. The aim of this book is to create a comprehensive source on support vector machine applications, especially some recent advances.

Effective SIMD Vectorization for Intel Xeon Phi Coprocessors

Directory of Open Access Journals (Sweden)

Xinmin Tian

2015-01-01

Full Text Available Efficiently exploiting SIMD vector units is one of the most important aspects in achieving high performance of the application code running on Intel Xeon Phi coprocessors. In this paper, we present several effective SIMD vectorization techniques such as less-than-full-vector loop vectorization, Intel MIC specific alignment optimization, and small matrix transpose/multiplication 2D vectorization implemented in the Intel C/C++ and Fortran production compilers for Intel Xeon Phi coprocessors. A set of workloads from several application domains is employed to conduct the performance study of our SIMD vectorization techniques. The performance results show that we achieved up to 12.5x performance gain on the Intel Xeon Phi coprocessor. We also demonstrate a 2000x performance speedup from the seamless integration of SIMD vectorization and parallelization.

Mechanism of Telomerase Inhibition Using a Small Inhibitory RNAs and Induction of Breast Tumor Cell Sensitization

Science.gov (United States)

2007-04-01

immunoprecipitation; TnT- transcription and translation. References Cited Barik , S. 2004. Control of nonsegmented negative-strand RNA virus replication by siRNA...Virus Res. 102: 27-35. Barquinero, J . et al. 2004. Retroviral vectors: new applications for an old tool. Gene Ther. 11(suppl 1): S3-S9...proteins and heterochromatin. Oncogene. 21: 553-563. Chen, J -L., Blasco, M.A., and Greider, C.W. 2000. Secondary structure of vertebrate telomerase RNA

Engineering BioBrick vectors from BioBrick parts

Directory of Open Access Journals (Sweden)

Knight Thomas F

2008-04-01

Full Text Available Abstract Background The underlying goal of synthetic biology is to make the process of engineering biological systems easier. Recent work has focused on defining and developing standard biological parts. The technical standard that has gained the most traction in the synthetic biology community is the BioBrick standard for physical composition of genetic parts. Parts that conform to the BioBrick assembly standard are BioBrick standard biological parts. To date, over 2,000 BioBrick parts have been contributed to, and are available from, the Registry of Standard Biological Parts. Results Here we extended the same advantages of BioBrick standard biological parts to the plasmid-based vectors that are used to provide and propagate BioBrick parts. We developed a process for engineering BioBrick vectors from BioBrick parts. We designed a new set of BioBrick parts that encode many useful vector functions. We combined the new parts to make a BioBrick base vector that facilitates BioBrick vector construction. We demonstrated the utility of the process by constructing seven new BioBrick vectors. We also successfully used the resulting vectors to assemble and propagate other BioBrick standard biological parts. Conclusion We extended the principles of part reuse and standardization to BioBrick vectors. As a result, myriad new BioBrick vectors can be readily produced from all existing and newly designed BioBrick parts. We invite the synthetic biology community to (1 use the process to make and share new BioBrick vectors; (2 expand the current collection of BioBrick vector parts; and (3 characterize and improve the available collection of BioBrick vector parts.

Bioreactor production of recombinant herpes simplex virus vectors.

Science.gov (United States)

Knop, David R; Harrell, Heather

2007-01-01

Serotypical application of herpes simplex virus (HSV) vectors to gene therapy (type 1) and prophylactic vaccines (types 1 and 2) has garnered substantial clinical interest recently. HSV vectors and amplicons have also been employed as helper virus constructs for manufacture of the dependovirus adeno-associated virus (AAV). Large quantities of infectious HSV stocks are requisite for these therapeutic applications, requiring a scalable vector manufacturing and processing platform comprised of unit operations which accommodate the fragility of HSV. In this study, production of a replication deficient rHSV-1 vector bearing the rep and cap genes of AAV-2 (denoted rHSV-rep2/cap2) was investigated. Adaptation of rHSV production from T225 flasks to a packed bed, fed-batch bioreactor permitted an 1100-fold increment in total vector production without a decrease in specific vector yield (pfu/cell). The fed-batch bioreactor system afforded a rHSV-rep2/cap2 vector recovery of 2.8 x 10(12) pfu. The recovered vector was concentrated by tangential flow filtration (TFF), permitting vector stocks to be formulated at greater than 1.5 x 10(9) pfu/mL.

Cosmological evolution in vector-tensor theories of gravity

International Nuclear Information System (INIS)

Beltran Jimenez, Jose; Maroto, Antonio L.

2009-01-01

We present a detailed study of the cosmological evolution in general vector-tensor theories of gravity without potential terms. We consider the evolution of the vector field throughout the expansion history of the Universe and carry out a classification of models according to the behavior of the vector field in each cosmological epoch. We also analyze the case in which the Universe is dominated by the vector field, performing a complete analysis of the system phase map and identifying those attracting solutions which give rise to accelerated expansion. Moreover, we consider the evolution in a universe filled with a pressureless fluid in addition to the vector field and study the existence of attractors in which we can have a transition from matter domination to vector domination with accelerated expansion so that the vector field may play the role of dark energy. We find that the existence of solutions with late-time accelerated expansion is a generic prediction of vector-tensor theories and that such solutions typically lead to the presence of future singularities. Finally, limits from local gravity tests are used to get constraints on the value of the vector field at small (Solar System) scales.

n-Characteristic Vector Fields of Contact Manifoldss

OpenAIRE

Hassanzadeh, Babak

2017-01-01

In present paper we define and study $n$-characteristic vector fields. We present definition of Tanaka-Webster connection, then use it for studying the behavior of $n$-characteristic vector fields. Also we show some results about of these vector fields by Tanaka-Webster connection.

Successful vectorization - reactor physics Monte Carlo code

International Nuclear Information System (INIS)

Martin, W.R.

1989-01-01

Most particle transport Monte Carlo codes in use today are based on the ''history-based'' algorithm, wherein one particle history at a time is simulated. Unfortunately, the ''history-based'' approach (present in all Monte Carlo codes until recent years) is inherently scalar and cannot be vectorized. In particular, the history-based algorithm cannot take advantage of vector architectures, which characterize the largest and fastest computers at the current time, vector supercomputers such as the Cray X/MP or IBM 3090/600. However, substantial progress has been made in recent years in developing and implementing a vectorized Monte Carlo algorithm. This algorithm follows portions of many particle histories at the same time and forms the basis for all successful vectorized Monte Carlo codes that are in use today. This paper describes the basic vectorized algorithm along with descriptions of several variations that have been developed by different researchers for specific applications. These applications have been mainly in the areas of neutron transport in nuclear reactor and shielding analysis and photon transport in fusion plasmas. The relative merits of the various approach schemes will be discussed and the present status of known vectorization efforts will be summarized along with available timing results, including results from the successful vectorization of 3-D general geometry, continuous energy Monte Carlo. (orig.)

A study of biorthogonal multiple vector-valued wavelets

International Nuclear Information System (INIS)

Han Jincang; Cheng Zhengxing; Chen Qingjiang

2009-01-01

The notion of vector-valued multiresolution analysis is introduced and the concept of biorthogonal multiple vector-valued wavelets which are wavelets for vector fields, is introduced. It is proved that, like in the scalar and multiwavelet case, the existence of a pair of biorthogonal multiple vector-valued scaling functions guarantees the existence of a pair of biorthogonal multiple vector-valued wavelet functions. An algorithm for constructing a class of compactly supported biorthogonal multiple vector-valued wavelets is presented. Their properties are investigated by means of operator theory and algebra theory and time-frequency analysis method. Several biorthogonality formulas regarding these wavelet packets are obtained.

3-D Vector Flow Imaging

DEFF Research Database (Denmark)

Holbek, Simon

, if this significant reduction in the element count can still provide precise and robust 3-D vector flow estimates in a plane. The study concludes that the RC array is capable of estimating precise 3-D vector flow both in a plane and in a volume, despite the low channel count. However, some inherent new challenges...... ultrasonic vector flow estimation and bring it a step closer to a clinical application. A method for high frame rate 3-D vector flow estimation in a plane using the transverse oscillation method combined with a 1024 channel 2-D matrix array is presented. The proposed method is validated both through phantom...... hampers the task of real-time processing. In a second study, some of the issue with the 2-D matrix array are solved by introducing a 2-D row-column (RC) addressing array with only 62 + 62 elements. It is investigated both through simulations and via experimental setups in various flow conditions...

Black holes in vector-tensor theories

Energy Technology Data Exchange (ETDEWEB)

Heisenberg, Lavinia [Institute for Theoretical Studies, ETH Zurich, Clausiusstrasse 47, 8092 Zurich (Switzerland); Kase, Ryotaro; Tsujikawa, Shinji [Department of Physics, Faculty of Science, Tokyo University of Science, 1-3, Kagurazaka, Shinjuku-ku, Tokyo 162-8601 (Japan); Minamitsuji, Masato, E-mail: lavinia.heisenberg@eth-its.ethz.ch, E-mail: r.kase@rs.tus.ac.jp, E-mail: masato.minamitsuji@tecnico.ulisboa.pt, E-mail: shinji@rs.kagu.tus.ac.jp [Centro Multidisciplinar de Astrofisica—CENTRA, Departamento de Fisica, Instituto Superior Tecnico—IST, Universidade de Lisboa—UL, Avenida Rovisco Pais 1, 1049-001 Lisboa (Portugal)

2017-08-01

We study static and spherically symmetric black hole (BH) solutions in second-order generalized Proca theories with nonminimal vector field derivative couplings to the Ricci scalar, the Einstein tensor, and the double dual Riemann tensor. We find concrete Lagrangians which give rise to exact BH solutions by imposing two conditions of the two identical metric components and the constant norm of the vector field. These exact solutions are described by either Reissner-Nordström (RN), stealth Schwarzschild, or extremal RN solutions with a non-trivial longitudinal mode of the vector field. We then numerically construct BH solutions without imposing these conditions. For cubic and quartic Lagrangians with power-law couplings which encompass vector Galileons as the specific cases, we show the existence of BH solutions with the difference between two non-trivial metric components. The quintic-order power-law couplings do not give rise to non-trivial BH solutions regular throughout the horizon exterior. The sixth-order and intrinsic vector-mode couplings can lead to BH solutions with a secondary hair. For all the solutions, the vector field is regular at least at the future or past horizon. The deviation from General Relativity induced by the Proca hair can be potentially tested by future measurements of gravitational waves in the nonlinear regime of gravity.

Investigation of Optimal Integrated Circuit Raster Image Vectorization Method

Directory of Open Access Journals (Sweden)

Leonas Jasevičius

2011-03-01

Full Text Available Visual analysis of integrated circuit layer requires raster image vectorization stage to extract layer topology data to CAD tools. In this paper vectorization problems of raster IC layer images are presented. Various line extraction from raster images algorithms and their properties are discussed. Optimal raster image vectorization method was developed which allows utilization of common vectorization algorithms to achieve the best possible extracted vector data match with perfect manual vectorization results. To develop the optimal method, vectorized data quality dependence on initial raster image skeleton filter selection was assessed.Article in Lithuanian

Environmental management: a re-emerging vector control strategy.

Science.gov (United States)

Ault, S K

1994-01-01

Vector control may be accomplished by environmental management (EM), which consists of permanent or long-term modification of the environment, temporary or seasonal manipulation of the environment, and modifying or changing our life styles and practices to reduce human contact with infective vectors. The primary focus of this paper is EM in the control of human malaria, filariasis, arboviruses, Chagas' disease, and schistosomiasis. Modern EM developed as a discipline based primarily in ecologic principles and lessons learned from the adverse environmental impacts of rural development projects. Strategies such as the suppression of vector populations through the provision of safe water supplies, proper sanitation, solid waste management facilities, sewerage and excreta disposal systems, water manipulation in dams and irrigation systems, vector diversion by zooprophylaxis, and vector exclusion by improved housing, are discussed with appropriate examples. Vectors of malaria, filariasis, Chagas' disease, and schistosomiasis have been controlled by drainage or filling aquatic breeding sites, improved housing and sanitation, the use of expanded polystyrene beads, zooprophylaxis, or the provision of household water supplies. Community participation has been effective in the suppression of dengue vectors in Mexico and the Dominican Republic. Alone or combined with other vector control methods, EM has been proven to be a successful approach to vector control in a number of places. The future of EM in vector control looks promising.

TimesVector: a vectorized clustering approach to the analysis of time series transcriptome data from multiple phenotypes.

Science.gov (United States)

Jung, Inuk; Jo, Kyuri; Kang, Hyejin; Ahn, Hongryul; Yu, Youngjae; Kim, Sun

2017-12-01

Identifying biologically meaningful gene expression patterns from time series gene expression data is important to understand the underlying biological mechanisms. To identify significantly perturbed gene sets between different phenotypes, analysis of time series transcriptome data requires consideration of time and sample dimensions. Thus, the analysis of such time series data seeks to search gene sets that exhibit similar or different expression patterns between two or more sample conditions, constituting the three-dimensional data, i.e. gene-time-condition. Computational complexity for analyzing such data is very high, compared to the already difficult NP-hard two dimensional biclustering algorithms. Because of this challenge, traditional time series clustering algorithms are designed to capture co-expressed genes with similar expression pattern in two sample conditions. We present a triclustering algorithm, TimesVector, specifically designed for clustering three-dimensional time series data to capture distinctively similar or different gene expression patterns between two or more sample conditions. TimesVector identifies clusters with distinctive expression patterns in three steps: (i) dimension reduction and clustering of time-condition concatenated vectors, (ii) post-processing clusters for detecting similar and distinct expression patterns and (iii) rescuing genes from unclassified clusters. Using four sets of time series gene expression data, generated by both microarray and high throughput sequencing platforms, we demonstrated that TimesVector successfully detected biologically meaningful clusters of high quality. TimesVector improved the clustering quality compared to existing triclustering tools and only TimesVector detected clusters with differential expression patterns across conditions successfully. The TimesVector software is available at http://biohealth.snu.ac.kr/software/TimesVector/. sunkim.bioinfo@snu.ac.kr. Supplementary data are available at

Vector assembly of colloids on monolayer substrates

Science.gov (United States)

Jiang, Lingxiang; Yang, Shenyu; Tsang, Boyce; Tu, Mei; Granick, Steve

2017-06-01

The key to spontaneous and directed assembly is to encode the desired assembly information to building blocks in a programmable and efficient way. In computer graphics, raster graphics encodes images on a single-pixel level, conferring fine details at the expense of large file sizes, whereas vector graphics encrypts shape information into vectors that allow small file sizes and operational transformations. Here, we adapt this raster/vector concept to a 2D colloidal system and realize `vector assembly' by manipulating particles on a colloidal monolayer substrate with optical tweezers. In contrast to raster assembly that assigns optical tweezers to each particle, vector assembly requires a minimal number of optical tweezers that allow operations like chain elongation and shortening. This vector approach enables simple uniform particles to form a vast collection of colloidal arenes and colloidenes, the spontaneous dissociation of which is achieved with precision and stage-by-stage complexity by simply removing the optical tweezers.

Herbivore arthropods benefit from vectoring plant viruses

NARCIS (Netherlands)

Belliure, B.; Janssen, A.; Maris, P.C.; Peters, D.; Sabelis, M.W.

2005-01-01

Plants infected with pathogens often attract the pathogens' vectors, but it is not clear if this is advantageous to the vectors. We therefore quantified the direct and indirect (through the host plant) effects of a pathogen on its vector. A positive direct effect of the plant-pathogenic Tomato

Meromorphic Vector Fields and Circle Packings

DEFF Research Database (Denmark)

Dias, Kealey

The objective of the Ph.D. project is to initiate a classification of bifurcations of meromorphic vector fields and to clarify their relation to circle packings. Technological applications are to image analysis and to effective grid generation using discrete conformal mappings. The two branches...... of dynamical systems, continuous and discrete, correspond to the study of differential equations (vector fields) and iteration of mappings respectively. In holomorphic dynamics, the systems studied are restricted to those described by holomorphic (complex analytic) functions or meromorphic (allowing poles...... as singularities) functions. There already exists a well-developed theory for iterative holomorphic dynamical systems, and successful relations found between iteration theory and flows of vector fields have been one of the main motivations for the recent interest in holomorphic vector fields. Restricting...

Characterizing Convexity of Games using Marginal Vectors

NARCIS (Netherlands)

van Velzen, S.; Hamers, H.J.M.; Norde, H.W.

2003-01-01

In this paper we study the relation between convexity of TU games and marginal vectors.We show that if specfic marginal vectors are core elements, then the game is convex.We characterize sets of marginal vectors satisfying this property, and we derive the formula for the minimum number of marginal

Outcomes of human immunodeficiency virus-infected children after anti-retroviral therapy in Malaysia.

Science.gov (United States)

Moy, Fong Siew; Fahey, Paul; Nik Yusoff, Nik K; Razali, Kamarul A; Nallusamy, Revathy

2015-02-01

To describe outcome and examine factors associated with mortality among human immunodeficiency virus (HIV)-infected children in Malaysia after anti-retroviral therapy (ART). Retrospective and prospective data collected through March 2009 from children in four different states in Malaysia enrolled in TREAT Asia's Pediatric HIV Observational Database were analysed. Of 347 children in the cohort, only 278 (80.1%) were commenced on ART. The median CD4 count and median age at baseline prior to ART was 272 cells/μL and 4.2 years (interquartile range (IQR): 1.4, 7.4 years), respectively. The median duration of follow-up was 3.7 years (IQR: 1.8, 6.0) with 32 deaths giving a crude mortality rate of 2.86 per 100 child-years. The mortality rate highest in the first 6 months of ART was 10.62 per 100 child-years and declined to 1.83 per 100 child-years thereafter. On univariate analyses, only baseline median CD4 percentage, weight for age z score, height for age z score and anaemia were significantly associated with mortality. Upon including all four of these predictors into a single multivariate model, only weight for age z score remained statistically significantly predictive of mortality. Children commenced on ART had high mortality in the first 6 months especially in those with low CD4 percentage, wasting and anaemia. Poor nutritional status is an important independent predictor of mortality in this study. Besides initiating ART therapy, nutritional support and intervention must receive the utmost attention. © 2014 The Authors. Journal of Paediatrics and Child Health © 2014 Paediatrics and Child Health Division (Royal Australasian College of Physicians).

How effective is integrated vector management against malaria and lymphatic filariasis where the diseases are transmitted by the same vector?

OpenAIRE

Stone, C.; Lindsay, S.W.; Chitnis, N.

2014-01-01

Background: The opportunity to integrate vector management across multiple vector-borne diseases is particularly plausible for malaria and lymphatic filariasis (LF) control where both diseases are transmitted by the same vector. To date most examples of integrated control targeting these diseases have been unanticipated consequences of malaria vector control, rather than planned strategies that aim to maximize the efficacy and take the complex ecological and biological interactions between th...

Enhanced efficacy of radiation-induced gene therapy in mice bearing lung adenocarcinoma xenografts using hypoxia responsive elements

International Nuclear Information System (INIS)

Wang Wei-dong; Chen Zheng-tang; Li De-zhi; Duan Yu-zhong; Cao Zheng-huai; Li Rong

2005-01-01

The aim of the present study was to investigate whether the hypoxia responsive element (HRE) could be used to enhance suicide gene (HSV-tk) expression and tumoricidal activity in radiation-controlled gene therapy of human lung adenocarcinoma xenografts. A chimeric promoter, HRE-Egr, was generated by directly linking a 0.3-kb fragment of HRE to a 0.6-kb human Egr-1 promoter. Retroviral vectors containing luciferase or the HSV-tk gene driven by Egr-1 or HRE-Egr were constructed. A human adenocarcinoma cell line (A549) was stably transfected with the above vectors using the lipofectamine method. The sensitivity of transfected cells to prodrug ganciclovir (GCV) and cell survival rates were analyzed after exposure to a dose of 2 Gy radiation and hypoxia (1%). In vivo, tumor xenografts in BALB/c mice were transfected with the constructed retroviruses and irradiated to a total dose of 6 Gy, followed by GCV treatment (20 mg/kg for 14 days). When the HSV-tk gene controlled by the HRE-Egr promoter was introduced into A549 cells by a retroviral vector, the exposure to 1% O 2 and 2 Gy radiation induced significant enhancement of GCV cytotoxicity to the cells. Moreover, in nude mice bearing solid tumor xenografts, only the tumors infected with the hybrid promoter-containing virus gradually disappeared after GCV administration and radiation. These results indicate that HRE can enhance transgene expression and tumoricidal activity in HSV-tk gene therapy controlled by ionizing radiation in hypoxic human lung adenocarcinoma. (author)

Sustainability of keratinocyte gene transfer and cell survival in vivo.

Science.gov (United States)

Choate, K A; Khavari, P A

1997-05-20

The epidermis is an attractive site for therapeutic gene delivery because it is accessible and capable of delivering polypeptides to the systemic circulation. A number of difficulties, however, have emerged in attempts at cutaneous gene delivery, and central among these is an inability to sustain therapeutic gene production. We have examined two major potential contributing factors, viral vector stamina and involvement of long-lived epidermal progenitor cells. Human keratinocytes were either untreated or transduced with a retroviral vector for beta-galactosidase (beta-Gal) at > 99% efficiency and then grafted onto immunodeficient mice to regenerate human epidermis. Human epidermis was monitored in vivo after grafting for clinical and histologic appearance as well as for gene expression. Although integrated vector sequences persisted unchanged in engineered epidermis at 10 weeks post-grafting, retroviral long terminal repeat (LTR)-driven beta-Gal expression ceased in vivo after approximately 4 weeks. Endogenous cellular promoters, however, maintained consistently normal gene expression levels without evidence of time-dependent decline, as determined by immunostaining with species-specific antibodies for human involucrin, filaggrin, keratinocyte transglutaminase, keratin 10, type VII collagen, and Laminin 5 proteins out to week 14 post-grafting. Transduced human keratinocytes generated multilayer epidermis sustained through multiple epidermal turnover cycles; this epidermis demonstrated retention of a spatially appropriate pattern of basal and suprabasal epidermal marker gene expression. These results confirm previous findings suggesting that viral promoter-driven gene expression is not durable and demonstrate that keratinocytes passaged in vitro can regenerate and sustain normal epidermis for prolonged periods.

Two-dimensional gauge model with vector U(1) and axial-vector U(1) symmetries

International Nuclear Information System (INIS)

Watabiki, Y.

1989-01-01

We have succeeded in constructing a two-dimensional gauge model with both vector U(1) and axial-vector U(1) symmetries. This model is exactly solvable. The Schwinger term vanishes in this model as a consequence of the above symmetries, and negative-norm states appear. However, the norms of physical states are always positive semidefinite due to the gauge symmetries

Air travel and vector-borne disease movement.

Science.gov (United States)

Tatem, A J; Huang, Z; Das, A; Qi, Q; Roth, J; Qiu, Y

2012-12-01

Recent decades have seen substantial expansions in the global air travel network and rapid increases in traffic volumes. The effects of this are well studied in terms of the spread of directly transmitted infections, but the role of air travel in the movement of vector-borne diseases is less well understood. Increasingly however, wider reaching surveillance for vector-borne diseases and our improving abilities to map the distributions of vectors and the diseases they carry, are providing opportunities to better our understanding of the impact of increasing air travel. Here we examine global trends in the continued expansion of air transport and its impact upon epidemiology. Novel malaria and chikungunya examples are presented, detailing how geospatial data in combination with information on air traffic can be used to predict the risks of vector-borne disease importation and establishment. Finally, we describe the development of an online tool, the Vector-Borne Disease Airline Importation Risk (VBD-Air) tool, which brings together spatial data on air traffic and vector-borne disease distributions to quantify the seasonally changing risks for importation to non-endemic regions. Such a framework provides the first steps towards an ultimate goal of adaptive management based on near real time flight data and vector-borne disease surveillance.

Bunyavirus-Vector Interactions

Directory of Open Access Journals (Sweden)

Kate McElroy Horne

2014-11-01

Full Text Available The Bunyaviridae family is comprised of more than 350 viruses, of which many within the Hantavirus, Orthobunyavirus, Nairovirus, Tospovirus, and Phlebovirus genera are significant human or agricultural pathogens. The viruses within the Orthobunyavirus, Nairovirus, and Phlebovirus genera are transmitted by hematophagous arthropods, such as mosquitoes, midges, flies, and ticks, and their associated arthropods not only serve as vectors but also as virus reservoirs in many cases. This review presents an overview of several important emerging or re-emerging bunyaviruses and describes what is known about bunyavirus-vector interactions based on epidemiological, ultrastructural, and genetic studies of members of this virus family.

Lyapunov, singular and bred vectors in a multi-scale system: an empirical exploration of vectors related to instabilities

International Nuclear Information System (INIS)

Norwood, Adrienne; Kalnay, Eugenia; Ide, Kayo; Yang, Shu-Chih; Wolfe, Christopher

2013-01-01

We compute and compare the three types of vectors frequently used to explore the instability properties of dynamical models, namely Lyapunov vectors (LVs), singular vectors (SVs) and bred vectors (BVs) in two systems, using the Wolfe–Samelson (2007 Tellus A 59 355–66) algorithm to compute all of the Lyapunov vectors. The first system is the Lorenz (1963 J. Atmos. Sci. 20 130–41) three-variable model. Although the leading Lyapunov vector, LV1, grows fastest globally, the second Lyapunov vector, LV2, which has zero growth globally, often grows faster than LV1 locally. Whenever this happens, BVs grow closer to LV2, suggesting that in larger atmospheric or oceanic models where several instabilities can grow in different areas of the world, BVs will grow toward the fastest growing local unstable mode. A comparison of their growth rates at different times shows that all three types of dynamical vectors have the ability to predict regime changes and the duration of the new regime based on their growth rates in the last orbit of the old regime, as shown for BVs by Evans et al (2004 Bull. Am. Meteorol. Soc. 520–4). LV1 and BVs have similar predictive skill, LV2 has a tendency to produce false alarms, and even LV3 shows that maximum decay is also associated with regime change. Initial and final SVs grow much faster and are the most accurate predictors of regime change, although the characteristics of the initial SVs are strongly dependent on the length of the optimization window. The second system is the toy ‘ocean-atmosphere’ model developed by Peña and Kalnay (2004 Nonlinear Process. Geophys. 11 319–27) coupling three Lorenz (1963 J. Atmos. Sci. 20 130–41) systems with different time scales, in order to test the effects of fast and slow modes of growth on the dynamical vectors. A fast ‘extratropical atmosphere’ is weakly coupled to a fast ‘tropical atmosphere’ which is, in turn, strongly coupled to a slow ‘ocean’ system, the latter coupling

Generalized 2-vector spaces and general linear 2-groups

OpenAIRE

Elgueta, Josep

2008-01-01

In this paper a notion of {\\it generalized 2-vector space} is introduced which includes Kapranov and Voevodsky 2-vector spaces. Various kinds of generalized 2-vector spaces are considered and examples are given. The existence of non free generalized 2-vector spaces and of generalized 2-vector spaces which are non Karoubian (hence, non abelian) categories is discussed, and it is shown how any generalized 2-vector space can be identified with a full subcategory of an (abelian) functor category ...

The charge form factor of the neutron from sup 2 H-vector, (e-vector, e' n)p

CERN Document Server

Passchier, I; Szczerba, D; Alarcon, R; Bauer, T S; Boersma, D J; Van der Brand, J F J; Bulten, H J; Ferro-Luzzi, M; Higinbotham, D W; Jager, C W D; Klous, S; Kolster, H; Lang, J; Nikolenko, D M; Nooren, G J; Norum, B E; Poolman, H R; Rachek, Igor A; Simani, M C; Six, E; Vries, H D; Wang, K; Zhou, Z L

2000-01-01

We report on the first measurement of spin-correlation parameters in quasifree electron scattering from vector-polarized deuterium. Polarized electrons were injected into an electron storage ring at a beam energy of 720 MeV. A Siberian snake was employed to preserve longitudinal polarization at the interaction point. Vector-polarized deuterium was produced by an atomic beam source and injected into an open-ended cylindrical cell, internal to the electron storage ring. The spin correlation parameter A sup V sub e sub d was measured for the reaction sup 2 H-vector, (e-vector, e'n)p at a four-momentum transfer squared of 0.21 (GeV/c) sup 2 from which a value for the charge form factor of the neutron was extracted.

Construction of expression vectors carrying mouse peroxisomal ...

African Journals Online (AJOL)

The aim of this study was to construct expression vectors carrying mouse peroxisomal protein gene (PEP-cDNA) in prokaryotic and mammalian expression vectors in ... pGEX6p2-PEP and pUcD3-FLAG-PEP constructed vectors were transformed into the one shot TOP10 and JM105 bacterial competent cells, respectively.

Vector Fields and Flows on Differentiable Stacks

DEFF Research Database (Denmark)

A. Hepworth, Richard

2009-01-01

This paper introduces the notions of vector field and flow on a general differentiable stack. Our main theorem states that the flow of a vector field on a compact proper differentiable stack exists and is unique up to a uniquely determined 2-cell. This extends the usual result on the existence...... of vector fields....

Extremal vectors and rectifiability | Enflo | Quaestiones Mathematicae

African Journals Online (AJOL)

Extremal vectors and rectifiability. ... The concept of extremal vectors of a linear operator with a dense range but not onto on a Hilbert space was introduced by P. Enflo in 1996 as a new approach to study invariant subspaces ... We show that in general curves that map numbers to backward minimal vectors are not rectifiable.

Integrated vector management for malaria control

Directory of Open Access Journals (Sweden)

Impoinvil Daniel E

2008-12-01

Full Text Available Abstract Integrated vector management (IVM is defined as "a rational decision-making process for the optimal use of resources for vector control" and includes five key elements: 1 evidence-based decision-making, 2 integrated approaches 3, collaboration within the health sector and with other sectors, 4 advocacy, social mobilization, and legislation, and 5 capacity-building. In 2004, the WHO adopted IVM globally for the control of all vector-borne diseases. Important recent progress has been made in developing and promoting IVM for national malaria control programmes in Africa at a time when successful malaria control programmes are scaling-up with insecticide-treated nets (ITN and/or indoor residual spraying (IRS coverage. While interventions using only ITNs and/or IRS successfully reduce transmission intensity and the burden of malaria in many situations, it is not clear if these interventions alone will achieve those critical low levels that result in malaria elimination. Despite the successful employment of comprehensive integrated malaria control programmes, further strengthening of vector control components through IVM is relevant, especially during the "end-game" where control is successful and further efforts are required to go from low transmission situations to sustained local and country-wide malaria elimination. To meet this need and to ensure sustainability of control efforts, malaria control programmes should strengthen their capacity to use data for decision-making with respect to evaluation of current vector control programmes, employment of additional vector control tools in conjunction with ITN/IRS tactics, case-detection and treatment strategies, and determine how much and what types of vector control and interdisciplinary input are required to achieve malaria elimination. Similarly, on a global scale, there is a need for continued research to identify and evaluate new tools for vector control that can be integrated with

Applications of the conserved vector current theory and the partially conserved axial-vector current theory to nuclear beta-decays

International Nuclear Information System (INIS)

Tint, M.

The contribution of the mesonic exchange effect to the conserved vector current in the first forbidden β-decay of Ra E is estimated under the headings: (1) The conserved vector current. (2) The CVC theory and the first forbidden β-decays. (3) Shell model calculations of some matrix-elements. (4) Direct calculation of the exchange term. Considering the mesonic exchange effect in the axial vector-current of β-decay the partially conserved axial vector current theory and experimental results of the process p + p → d + π + are examined. (U.K.)

Feature Vector Construction Method for IRIS Recognition

Science.gov (United States)

Odinokikh, G.; Fartukov, A.; Korobkin, M.; Yoo, J.

2017-05-01

One of the basic stages of iris recognition pipeline is iris feature vector construction procedure. The procedure represents the extraction of iris texture information relevant to its subsequent comparison. Thorough investigation of feature vectors obtained from iris showed that not all the vector elements are equally relevant. There are two characteristics which determine the vector element utility: fragility and discriminability. Conventional iris feature extraction methods consider the concept of fragility as the feature vector instability without respect to the nature of such instability appearance. This work separates sources of the instability into natural and encodinginduced which helps deeply investigate each source of instability independently. According to the separation concept, a novel approach of iris feature vector construction is proposed. The approach consists of two steps: iris feature extraction using Gabor filtering with optimal parameters and quantization with separated preliminary optimized fragility thresholds. The proposed method has been tested on two different datasets of iris images captured under changing environmental conditions. The testing results show that the proposed method surpasses all the methods considered as a prior art by recognition accuracy on both datasets.

Vectorization of Monte Carlo particle transport

International Nuclear Information System (INIS)

Burns, P.J.; Christon, M.; Schweitzer, R.; Lubeck, O.M.; Wasserman, H.J.; Simmons, M.L.; Pryor, D.V.

1989-01-01

This paper reports that fully vectorized versions of the Los Alamos National Laboratory benchmark code Gamteb, a Monte Carlo photon transport algorithm, were developed for the Cyber 205/ETA-10 and Cray X-MP/Y-MP architectures. Single-processor performance measurements of the vector and scalar implementations were modeled in a modified Amdahl's Law that accounts for additional data motion in the vector code. The performance and implementation strategy of the vector codes are related to architectural features of each machine. Speedups between fifteen and eighteen for Cyber 205/ETA-10 architectures, and about nine for CRAY X-MP/Y-MP architectures are observed. The best single processor execution time for the problem was 0.33 seconds on the ETA-10G, and 0.42 seconds on the CRAY Y-MP

Horizontal vectorization of electron repulsion integrals.

Science.gov (United States)

Pritchard, Benjamin P; Chow, Edmond

2016-10-30

We present an efficient implementation of the Obara-Saika algorithm for the computation of electron repulsion integrals that utilizes vector intrinsics to calculate several primitive integrals concurrently in a SIMD vector. Initial benchmarks display a 2-4 times speedup with AVX instructions over comparable scalar code, depending on the basis set. Speedup over scalar code is found to be sensitive to the level of contraction of the basis set, and is best for (lAlB|lClD) quartets when lD  = 0 or lB=lD=0, which makes such a vectorization scheme particularly suitable for density fitting. The basic Obara-Saika algorithm, how it is vectorized, and the performance bottlenecks are analyzed and discussed. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

A vector lattice version of Radström's embedding theorem

African Journals Online (AJOL)

Radström's embedding theorem for 'near vector spaces', which are essentially vector spaces without additive inverses, is extended to embeddings of 'near vector lattices', which are essentially vector lattices without additive inverses, into vector lattices. If the 'near vector space' is endowed with a metric, properties on the ...

Anti-retroviral therapy fails to restore the severe Th-17: Tc-17 imbalance observed in peripheral blood during simian immunodeficiency virus infection.

Science.gov (United States)

Kader, M; Bixler, S; Piatak, M; Lifson, J; Mattapallil, J J

2009-10-01

Human immuno deficiency virus and simian immunodeficiency virus infections are characterized by a severe loss of Th-17 cells (IL-17(+)CD4(+) T cells) that has been associated with disease progression and systemic dissemination of bacterial infections. Anti-retroviral therapy (ART) has led to repopulation of CD4(+) T cells in peripheral tissues with little sustainable repopulation in mucosal tissues. Given the central importance of Th-17 cells in mucosal homeostasis, it is not known if the failure of ART to permanently repopulate mucosal tissues is associated with a failure to restore Th-17 cells that are lost during infection. Dynamics of alpha4(+)beta7(hi) CD4(+) T cells in peripheral blood of SIV infected rhesus macaques were evaluated and compared to animals that were treated with ART. The frequency of Th-17 and Tc-17 cells was determined following infection and after therapy. Relative expression of IL-21, IL-23, and TGFbeta was determined using Taqman PCR. Treatment of SIV infected rhesus macaques with anti-retroviral therapy was associated with a substantial repopulation of mucosal homing alpha4(+)beta7(hi)CD4(+) T cells in peripheral blood. This repopulation, however, was not accompanied by a restoration of Th-17 responses. Interestingly, SIV infection was associated with an increase in Tc-17 responses (IL-17(+)CD8(+) T cells) suggesting to a skewing in the ratio of Th-17: Tc-17 cells from a predominantly Th-17 phenotype to a predominantly Tc-17 phenotype. Surprisingly, Tc-17 responses remained high during the course of therapy suggesting that ART failed to correct the imbalance in Th-17 : Tc-17 responses induced following SIV infection. ART was associated with substantial repopulation of alpha4(+)beta7(hi) CD4(+) T cells in peripheral blood with little or no rebound of Th-17 cells. On the other hand, repopulation of alpha4(+)beta7(hi) CD4(+) T cells was accompanied by persistence of high levels of Tc-17 cells in peripheral blood. The dysregulation of Th-17

Retroviral DNA--the silent winner: blood transfusion containing latent feline leukemia provirus causes infection and disease in naïve recipient cats.

Science.gov (United States)

Nesina, Stefanie; Katrin Helfer-Hungerbuehler, A; Riond, Barbara; Boretti, Felicitas S; Willi, Barbara; Meli, Marina L; Grest, Paula; Hofmann-Lehmann, Regina

2015-12-21

veterinary medicine, such as the requirement for testing blood donors and blood products for FeLV provirus by sensitive polymerase chain reaction, but are also of general interest by revealing the importance of latent retroviral DNA in infected hosts. When aiming to eliminate a retroviral infection from a population, provirus carriers must be considered.

Search for intermediate vector bosons

International Nuclear Information System (INIS)

Klajn, D.B.; Rubbia, K.; Meer, S.

1983-01-01

Problem of registration and search for intermediate vector bosons is discussed. According to weak-current theory there are three intermediate vector bosons with +1(W + )-1(W - ) and zero (Z 0 ) electric charges. It was suggested to conduct the investigation into particles in 1976 by cline, Rubbia and Makintair using proton-antiproton beams. Major difficulties of the experiment are related to the necessity of formation of sufficient amount of antiparticles and the method of antiproton beam ''cooling'' for the purpose of reduction of its random movements. The stochastic method was suggested by van der Meer in 1968 as one of possible cooling methods. Several large detectors were designed for searching intermediate vector bosons

On vector fields having properties of Reeb fields

OpenAIRE