31 research outputs found

    Wildfire Risk as a Socioecological Pathology

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    Wildfire risk in temperate forests has become a nearly intractable problem that can be characterized as a socioecological “pathology”: that is, a set of complex and problematic interactions among social and ecological systems across multiple spatial and temporal scales. Assessments of wildfire risk could benefit from recognizing and accounting for these interactions in terms of socioecological systems, also known as coupled natural and human systems (CNHS). We characterize the primary social and ecological dimensions of the wildfire risk pathology, paying particular attention to the governance system around wildfire risk, and suggest strategies to mitigate the pathology through innovative planning approaches, analytical tools, and policies. We caution that even with a clear understanding of the problem and possible solutions, the system by which human actors govern fire-prone forests may evolve incrementally in imperfect ways and can be expected to resist change even as we learn better ways to manage CNHS

    Towards a Clinically Relevant Lentiviral Transduction Protocol for Primary Human CD34+ Hematopoietic Stem/Progenitor Cells

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    Background: Hematopoietic stem cells (HSC), in particular mobilized peripheral blood stem cells, represent an attractive target for cell and gene therapy. Efficient gene delivery into these target cells without compromising self-renewal and multipotency is crucial for the success of gene therapy. We investigated factors involved in the ex vivo transduction of CD34 + HSCs in order to develop a clinically relevant transduction protocol for gene delivery. Specifically sought was a protocol that allows for efficient transduction with minimal ex vivo manipulation without serum or other reagents of animal origin. Methodology/Principal Findings: Using commercially available G-CSF mobilized peripheral blood (PB) CD34 + cells as the most clinically relevant target, we systematically examined factors including the use of serum, cytokine combinations, prestimulation time, multiplicity of infection (MOI), transduction duration and the use of spinoculation and/or retronectin. A self-inactivating lentiviral vector (SIN-LV) carrying enhanced green fluorescent protein (GFP) was used as the gene delivery vehicle. HSCs were monitored for transduction efficiency, surface marker expression and cellular function. We were able to demonstrate that efficient gene transduction can be achieved with minimal ex vivo manipulation while maintaining the cellular function of transduced HSCs without serum or other reagents of animal origin. Conclusions/Significance: This study helps to better define factors relevant towards developing a standard clinical protocol for the delivery of SIN-LV into CD34 + cells

    Lack of Association between an Interleukin-I Receptor Antagonist Gene Polymorphism and Systemic Lupus Erythematosus

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    Non-MHC linked genes may contribute to genetic predisposition to the development of systemic lupus erythematosus. The possibility that cytokine genes may be involved was raised by the observation of increased frequency in expression of an uncommon allele of an interleukin-I receptor antagonist gene polymorphism and SLE in a recent U.K. study. We have not been able to show any significant differences in expression of this allele in SLE patients as a whole or in any patient subgroups. Our results actually show a slight decrease in the expression of this allele in SLE patients compared with healthy controls and in SLE patients with malar rash compared with SLE patients without malar rash

    Increased Frequency of the Uncommon Allele of a Tumour Necrosis Factor Alpha Gene Polymorphism in Rheumatoid Arthritis and Systemic Lupus Erythematosus

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    The frequency of the uncommon allele (TNF2) of a polymorphism in the promoter region of the tumour necrosis factor alpha (TN Fα) gene in patients with rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) was found to be 3 times that of the normal anglo-saxon population. In SLE patients, this allele was strongly associated with HLA-DR3 expression and was also more frequent in patients who did not have malar rash. Functional studies of normal monocyte cytokine production in vitro showed that this genotype was associated with increased IL-1α protein production but there were no differences in the production of TNFα protein

    CCR5 Targeted Cell Therapy for HIV and Prevention of Viral Escape

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    Allogeneic transplantation with CCR5-delta 32 (CCR5-d32) homozygous stem cells in an HIV infected individual in 2008, led to a sustained virus control and probably eradication of HIV. Since then there has been a high degree of interest to translate this approach to a wider population. There are two cellular ways to do this. The first one is to use a CCR5 negative cell source e.g., hematopoietic stem cells (HSC) to copy the initial finding. However, a recent case of a second allogeneic transplantation with CCR5-d32 homozygous stem cells suffered from viral escape of CXCR4 quasi-species. The second way is to knock down CCR5 expression by gene therapy. Currently, there are five promising techniques, three of which are presently being tested clinically. These techniques include zinc finger nucleases (ZFN), clustered regularly interspaced palindromic repeats/CRISPR-associated protein 9 nuclease (CRISPR/Cas9), transcription activator-like effectors nuclease (TALEN), short hairpin RNA (shRNA), and a ribozyme. While there are multiple gene therapy strategies being tested, in this review we reflect on our current knowledge of inhibition of CCR5 specifically and whether this approach allows for consequent viral escape

    Comparison of CD34<sup>+</sup> cell growth and transduction with various cytokine combinations.

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    <p>(A) Cytokine combinations used, ng/mL (B) Transduction efficiency in various cytokine combinations. * p<0.05, when compared to all other cytokine combinations (C) Clonogenic potential. Mock: non-transduced cells; Txd: transduced cells; C/BFU-E: Colony/blast forming units – erythroid; CFU-GM: Colony forming unit – granulocyte/macrophage; CFU-GEMM: Colony forming unit – granuloycte, erythroid, macrophage, megakaryocyte.</p

    Effects of 4, 24 or 48 h pre-stimulation on CD34<sup>+</sup> cell transduction, growth and differentiation.

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    <p>(A) Transduction efficiency 48 h post transduction. (B) Expansion of CD34<sup>+</sup> cells post transduction. (C)–(E) Expression of primitive markers 48 h post transduction, (C) CD34, (D) CD133 and (E) CD90. * p<0.05, when all combinations compared.</p
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