81 research outputs found

    Privatization, State Militarization through War, and Durable Social Exclusion in Post-Soviet Armenia

    Get PDF
    In the literature focusing on various aspects of the twin transitions from socialism, development and social well-being are mainly analyzed with respect to privatization process (Stark and Bruszt 1998, Applegate 1994); economic growth and institutional design (North 1990; Elster, Offe, and Preuss 1998; Kolodko 1999; Norgaard 2000); party and election politics, the development of social networks and deliberative associations (Stark and Bruszt 1998); and the bargaining power of labor (Bandelj and Mahutga 2005). While the importance of these factors is not underestimated, this study addresses a significantly understudied theme – social exclusion as a consequence of overweening state power. The problem of social exclusion cuts to the core of the distribution of power in society; and in most of the post-Soviet societies, there has occurred predominantly negative change in societal power after 1990s, with vast power concentrated in the hands of governing elites. In the case of Armenia, the problem is specifically striking. This dissertation centers around durable social exclusion in post-Soviet Armenia generated as a consequence of the twin transition and explores the conditions that explain the high degree of social exclusion in contemporary Armenian society. It aims to answer the following research question: what factors contributed to the development of durable social exclusion in post-Soviet Armenia from 1988-2008? As an exploratory case study based on the examination of recent socio-economic and, more notably, political developments of post-Soviet Armenian state, this dissertation generates new hypotheses to study social exclusion. Appending to the mainstream literature that focuses on primarily the socio-economic drivers of social exclusion, I emphasize that not only consequences of economic reform affect the level of social exclusion, but also, and more significantly, the historic trajectory of the society. I argue that privatization was an important but not a sufficient factor in the emergence of social exclusion in post-Soviet Armenia. State militarization through war was another necessary and largely overlooked condition for the persistence of social exclusion in Armenia. The assessment of these hypotheses provides evidence that allows a test of whether privatization and militarization are plausible factors for the persistence of social exclusion in other developing countries

    Lovastatin induces apoptosis of ovarian cancer cells and synergizes with doxorubicin: potential therapeutic relevance

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Ovarian carcinoma is a rarely curable disease, for which new treatment options are required. As agents that block HMG-CoA reductase and the mevalonate pathway, the statin family of drugs are used in the treatment of hypercholesterolemia and have been shown to trigger apoptosis in a tumor-specific manner. Recent clinical trials show that the addition of statins to traditional chemotherapeutic strategies can increase efficacy of targeting statin-sensitive tumors. Our goal was to assess statin-induced apoptosis of ovarian cancer cells, either alone or in combination with chemotherapeutics, and then determine these mechanisms of action.</p> <p>Methods</p> <p>The effect of lovastatin on ovarian cancer cell lines was evaluated alone and in combination with cisplatin and doxorubicin using several assays (MTT, TUNEL, fixed PI, PARP cleavage) and synergy determined by evaluating the combination index. The mechanisms of action were evaluated using functional, molecular, and pharmacologic approaches.</p> <p>Results</p> <p>We demonstrate that lovastatin induces apoptosis of ovarian cancer cells in a p53-independent manner and synergizes with doxorubicin, a chemotherapeutic agent used to treat recurrent cases of ovarian cancer. Lovastatin drives ovarian tumor cell death by two mechanisms: first, by blocking HMG-CoA reductase activity, and second, by sensitizing multi-drug resistant cells to doxorubicin by a novel mevalonate-independent mechanism. This inhibition of drug transport, likely through inhibition of P-glycoprotein, potentiates both DNA damage and tumor cell apoptosis.</p> <p>Conclusions</p> <p>The results of this research provide pre-clinical data to warrant further evaluation of statins as potential anti-cancer agents to treat ovarian carcinoma. Many statins are inexpensive, off-patent generic drugs that are immediately available for use as anti-cancer agents. We provide evidence that lovastatin triggers apoptosis of ovarian cancer cells as a single agent by a mevalonate-dependent mechanism. Moreover, we also show lovastatin synergizes with doxorubicin, an agent administered for recurrent disease. This synergy occurs by a novel mevalonate-independent mechanism that antagonizes drug resistance, likely by inhibiting P-glycoprotein. These data raise important issues that may impact how statins can best be included in chemotherapy regimens.</p

    МАКРОЭКОНОМИЧЕСКАЯ МОДЕЛь КАЛЕЦКОГО С уЧЕТОМ ИНВЕСТИЦИОННОГО ВРЕМЕННОГО ЛАГА

    Get PDF
    The dependence of the gross domestic product on time ( Y ( t )) in macroeconomic Kalecki’s model in view of an investment temporary lag in the case of periodic dependence of the consumption function on time is investigated. As a result of solutions of linear ordinary differential equation and differential equation with lagging argument an analytical expressions for the Y ( t ) is received. Some aspects of influence of a temporary lag on character of variation of the function Y ( t ) are shown.Исследована зависимость валового внутреннего продукта от времени ( Y ( t )) в макроэкономической модели Калецкого с учетом инвестиционного временного лага в случае периодической зависимости функции потребления от времени. В результате решения обыкновенного линейного дифференциального уравнения и дифференциального уравнения с запаздывающим аргументом получены аналитические выражения для Y ( t ). Показаны некоторые аспекты влияния учета временного лага на характер изменения функции Y ( t )

    Type I IFN induces IL-10 production in an IL-27-independent manner and blocks responsiveness to IFN-gamma for production of IL-12 and bacterial killing in Mycobacterium tuberculosis-infected macrophages

    Get PDF
    Tuberculosis, caused by the intracellular bacterium Mycobacterium tuberculosis, currently causes ~1.4 million deaths per year, and it therefore remains a leading global health problem. The immune response during tuberculosis remains incompletely understood, particularly regarding immune factors that are harmful rather than protective to the host. Overproduction of the type I IFN family of cytokines is associated with exacerbated tuberculosis in both mouse models and in humans, although the mechanisms by which type I IFN promotes disease are not well understood. We have investigated the effect of type I IFN on M. tuberculosis-infected macrophages and found that production of host-protective cytokines such as TNF-a, IL-12, and IL-1ß is inhibited by exogenous type I IFN, whereas production of immunosuppressive IL-10 is promoted in an IL-27-independent manner. Furthermore, much of the ability of type I IFN to inhibit cytokine production was mediated by IL-10. Additionally, type I IFN compromised macrophage activation by the lymphoid immune response through severely disrupting responsiveness to IFN-?, including M. tuberculosis killing. These findings describe important mechanisms by which type I IFN inhibits the immune response during tuberculosis.This work was funded by Medical Research Council, U.K. Grant U117565642 and European Research Council Grant 294682-TB-PATH. M.S. and L.M.-T. were funded by the Fundacao para a Ciencia e Tecnologia, Portugal. M.S. is a Fundacao para a Ciencia e Tecnologia, Portugal investigator. L.M.T. was supported by Fundacao para a Ciencia e Tecnologia, Portugal Grant SFRH/BPD/77399/2011

    The Differential Interaction of Brucella and Ochrobactrum with Innate Immunity Reveals Traits Related to the Evolution of Stealthy Pathogens

    Get PDF
    International audienceBACKGROUND: During evolution, innate immunity has been tuned to recognize pathogen-associated molecular patterns. However, some alpha-Proteobacteria are stealthy intracellular pathogens not readily detected by this system. Brucella members follow this strategy and are highly virulent, but other Brucellaceae like Ochrobactrum are rhizosphere inhabitants and only opportunistic pathogens. To gain insight into the emergence of the stealthy strategy, we compared these two phylogenetically close but biologically divergent bacteria. METHODOLOGY/PRINCIPAL FINDINGS: In contrast to Brucella abortus, Ochrobactrum anthropi did not replicate within professional and non-professional phagocytes and, whereas neutrophils had a limited action on B. abortus, they were essential to control O. anthropi infections. O. anthropi triggered proinflammatory responses markedly lower than Salmonella enterica but higher than B. abortus. In macrophages and dendritic cells, the corresponding lipopolysaccharides reproduced these grades of activation, and binding of O. anthropi lipopolysaccharide to the TLR4 co-receptor MD-2 and NF-kappaB induction laid between those of B. abortus and enteric bacteria lipopolysaccharides. These differences correlate with reported variations in lipopolysaccharide core sugars, sensitivity to bactericidal peptides and outer membrane permeability. CONCLUSIONS/SIGNIFICANCE: The results suggest that Brucellaceae ancestors carried molecules not readily recognized by innate immunity, so that non-drastic variations led to the emergence of stealthy intracellular parasites. They also suggest that some critical envelope properties, like selective permeability, are profoundly altered upon modification of pathogen-associated molecular patterns, and that this represents a further adaptation to the host. It is proposed that this adaptive trend is relevant in other intracellular alpha-Proteobacteria like Bartonella, Rickettsia, Anaplasma, Ehrlichia and Wolbachia

    Lipopolysaccharides with acylation defects potentiate TLR4 signaling and shape T cell responses

    Get PDF
    Lipopolysaccharides or endotoxins are components of Gram-negative enterobacteria that cause septic shock in mammals. However, a LPS carrying hexa-acyl lipid A moieties is highly endotoxic compared to a tetra-acyl LPS and the latter has been considered as an antagonist of hexa-acyl LPS-mediated TLR4 signaling. We investigated the relationship between the structure and the function of bacterial LPS in the context of human and mouse dendritic cell activation. Strikingly, LPS with acylation defects were capable of triggering a strong and early TLR4-dependent DC activation, which in turn led to the activation of the proteasome machinery dampening the pro-inflammatory cytokine secretion. Upon activation with tetra-acyl LPS both mouse and human dendritic cells triggered CD4(+) T and CD8(+) T cell responses and, importantly, human myeloid dendritic cells favored the induction of regulatory T cells. Altogether, our data suggest that LPS acylation controlled by pathogenic bacteria might be an important strategy to subvert adaptive immunity

    Characterization of the apoptotic response of human leukemia cells to organosulfur compounds

    Get PDF
    Background: Novel therapeutic agents that selectively induce tumor cell death are urgently needed in the clinical management of cancers. Such agents would constitute effective adjuvant approaches to traditional chemotherapy regimens. Organosulfur compounds (OSCs), such as diallyl disulfide, have demonstrated anti-proliferative effects on cancer cells. We have previously shown that synthesized relatives of dysoxysulfone, a natural OSC derived from the Fijian medicinal plant, Dysoxylum richi, possess tumor-specific antiproliferative effects and are thus promising lead candidates. Methods: Because our structure-activity analyses showed that regions flanking the disulfide bond mediated specificity, we synthesized 18 novel OSCs by structural modification of the most promising dysoxysulfone derivatives. These compounds were tested for anti-proliferative and apoptotic activity in both normal and leukemic cells. Results: Six OSCs exhibited tumor-specific killing, having no effect on normal bone marrow, and are thus candidates for future toxicity studies. We then employed mRNA expression profiling to characterize the mechanisms by which different OSCs induce apoptosis. Using Gene Ontology analysis we show that each OSC altered a unique set of pathways, and that these differences could be partially rationalized from a transcription factor binding site analysis. For example, five compounds altered genes with a large enrichment of p53 binding sites in their promoter regions (p < 0.0001). Conclusions: Taken together, these data establish OSCs derivatized from dysoxysulfone as a novel group of compounds for development as anti-cancer agents

    The Lipopolysaccharide Core of Brucella abortus Acts as a Shield Against Innate Immunity Recognition

    Get PDF
    Innate immunity recognizes bacterial molecules bearing pathogen-associated molecular patterns to launch inflammatory responses leading to the activation of adaptive immunity. However, the lipopolysaccharide (LPS) of the gram-negative bacterium Brucella lacks a marked pathogen-associated molecular pattern, and it has been postulated that this delays the development of immunity, creating a gap that is critical for the bacterium to reach the intracellular replicative niche. We found that a B. abortus mutant in the wadC gene displayed a disrupted LPS core while keeping both the LPS O-polysaccharide and lipid A. In mice, the wadC mutant induced proinflammatory responses and was attenuated. In addition, it was sensitive to killing by non-immune serum and bactericidal peptides and did not multiply in dendritic cells being targeted to lysosomal compartments. In contrast to wild type B. abortus, the wadC mutant induced dendritic cell maturation and secretion of pro-inflammatory cytokines. All these properties were reproduced by the wadC mutant purified LPS in a TLR4-dependent manner. Moreover, the core-mutated LPS displayed an increased binding to MD-2, the TLR4 co-receptor leading to subsequent increase in intracellular signaling. Here we show that Brucella escapes recognition in early stages of infection by expressing a shield against recognition by innate immunity in its LPS core and identify a novel virulence mechanism in intracellular pathogenic gram-negative bacteria. These results also encourage for an improvement in the generation of novel bacterial vaccines

    Brucella beta 1,2 cyclic glucan is an activator of human and mouse dendritic cells

    Get PDF
    Bacterial cyclic glucans are glucose polymers that concentrate within the periplasm of alpha-proteobacteria. These molecules are necessary to maintain the homeostasis of the cell envelope by contributing to the osmolarity of Gram negative bacteria. Here, we demonstrate that Brucella beta 1,2 cyclic glucans are potent activators of human and mouse dendritic cells. Dendritic cells activation by Brucella beta 1,2 cyclic glucans requires TLR4, MyD88 and TRIF, but not CD14. The Brucella cyclic glucans showed neither toxicity nor immunogenicity compared to LPS and triggered antigen-specific CD8(+) T cell responses in vivo. These cyclic glucans also enhanced antigen-specific CD4(+) and CD8(+) T cell responses including cross-presentation by different human DC subsets. Brucella beta 1,2 cyclic glucans increased the memory CD4(+) T cell responses of blood mononuclear cells exposed to recombinant fusion proteins composed of anti-CD40 antibody and antigens from both hepatitis C virus and Mycobacterium tuberculosis. Thus cyclic glucans represent a new class of adjuvants, which might contribute to the development of effective antimicrobial therapies
    corecore