IL-2 Regulates SEB Induced Toxic Shock Syndrome in BALB/c Mice

BACKGROUND:Toxic Shock Syndrome (TSS) is characterized by fever, rash, hypotension, constitutional symptoms, and multi-organ involvement and is caused by Staphylococcus aureus enterotoxins such as Staphylococcal Enterotoxin B (SEB). SEB binds to the MHC-IIalpha chain and is recognized by the TCRbeta chain of the Vbeta8 TCR(+) T cells. The binding of SEB to Vbeta chain results in rapid activation of T cells and production of inflammatory cytokines, such as Interleukin-2 (IL-2), Interferon-gamma and Tumor Necrosis Factor-alpha which mediate TSS. Although IL2 was originally identified as the T cell growth factor and was proposed to contribute to T cell differentiation, its role in TSS remains unexplored. METHODOLOGY/PRINCIPAL FINDINGS:Mice were injected with D-Gal (25 mg/mouse). One hour after D-Galactosamine (D-Gal) injection each mouse was injected with SEB (20 microg/mouse. Mice were then observed for 72 hrs and death was recorded at different times. We tested Interleukin-12, IFNgamma, and IL-2 deficient mice (IL-2(-/-)), but only the IL-2 deficient mice were resistant to SEB induced toxic shock syndrome. More importantly reconstitution of IL-2 in IL-2 deficient mice restored the shock. Interestingly, SEB induced IL-2 production from T cells was dependent on p38MAPK activation in macrophages as inhibition of it in macrophages significantly inhibited IL-2 production from T cells. CONCLUSION:This study shows the importance of IL -2 in TSS which has not been previously explored and it also shows that regulating macrophages function can regulate T cells and TSS

An alternative to the hand searching gold standard: validating methodological search filters using relative recall

BACKGROUND: Search filters or hedges play an important role in evidence-based medicine but their development depends on the availability of a "gold standard" – a reference standard against which to establish the performance of the filter. We demonstrate the feasibility of using relative recall of included studies from multiple systematic reviews to validate methodological search filters as an alternative to validation against a gold standard formed through hand searching. METHODS: We identified 105 Cochrane reviews that used the Highly Sensitive Search Strategy (HSSS), included randomized or quasi-randomized controlled trials, and reported their included studies. We measured the ability of two published and one novel variant of the HSSS to retrieve the MEDLINE-index studies included in these reviews. RESULTS: The systematic reviews were comprehensive in their searches. 72% of included primary studies were indexed in MEDLINE. Relative recall of the three strategies ranged from .98 to .91 across all reviews and more comprehensive strategies showed higher recall. CONCLUSION: An approach using relative recall instead of a hand searching gold standard proved feasible and produced recall figures that were congruent with previously published figures for the HSSS. This technique would permit validation of a methodological filter using a collection of approximately 100 studies of the chosen design drawn from the included studies of multiple systematic reviews that used comprehensive search strategies

IFN-gamma Impairs Release of IL-8 by IL-1beta-stimulated A549 Lung Carcinoma Cells

Background Production of interferon (IFN)-gamma is key to efficient anti-tumor immunity. The present study was set out to investigate effects of IFNgamma on the release of the potent pro-angiogenic mediator IL-8 by human A549 lung carcinoma cells. Methods A549 cells were cultured and stimulated with interleukin (IL)-1beta alone or in combination with IFNgamma. IL-8 production by these cells was analyzed with enzyme linked immuno sorbent assay (ELISA). mRNA-expression was analyzed by real-time PCR and RNase protection assay (RPA), respectively. Expression of inhibitor-kappaBalpha, cellular IL-8, and cyclooxygenase-2 was analyzed by Western blot analysis. Results Here we demonstrate that IFNgamma efficiently reduced IL-8 secretion under the influence of IL-1beta. Surprisingly, real-time PCR analysis and RPA revealed that the inhibitory effect of IFNgamma on IL-8 was not associated with significant changes in mRNA levels. These observations concurred with lack of a modulatory activity of IFNgamma on IL-1beta-induced NF-kappaB activation as assessed by cellular IkappaB levels. Moreover, analysis of intracellular IL-8 suggests that IFNgamma modulated IL-8 secretion by action on the posttranslational level. In contrast to IL-8, IL-1beta-induced cyclooxygenase-2 expression and release of IL-6 were not affected by IFNgamma indicating that modulation of IL-1beta action by this cytokine displays specificity. Conclusions Data presented herein agree with an angiostatic role of IFNgamma as seen in rodent models of solid tumors and suggest that increasing T helper type 1 (Th1)-like functions in lung cancer patients e.g. by local delivery of IFNgamma may mediate therapeutic benefit via mechanisms that potentially include modulation of pro-angiogenic IL-8

Pim1 promotes human prostate cancer cell tumorigenicity and c-MYC transcriptional activity

<p>Abstract</p> <p>Background</p> <p>The serine/threonine kinase PIM1 has been implicated as an oncogene in various human cancers including lymphomas, gastric, colorectal and prostate carcinomas. In mouse models, Pim1 is known to cooperate with c-Myc to promote tumorigenicity. However, there has been limited analysis of the tumorigenic potential of Pim1 overexpression in benign and malignant human prostate cancer cells <it>in vivo</it>.</p> <p>Methods</p> <p>We overexpressed Pim1 in three human prostate cell lines representing different disease stages including benign (RWPE1), androgen-dependent cancer (LNCaP) and androgen-independent cancer (DU145). We then analyzed <it>in vitro </it>and <it>in vivo </it>tumorigenicity as well as the effect of Pim1 overexpression on c-MYC transcriptional activity by reporter assays and gene expression profiling using an inducible MYC-ER system. To validate that Pim1 induces tumorigenicity and target gene expression by modulating c-MYC transcriptional activity, we inhibited c-MYC using a small molecule inhibitor (10058-F4) or RNA interference.</p> <p>Results</p> <p>Overexpression of Pim1 alone was not sufficient to convert the benign RWPE1 cell to malignancy although it enhanced their proliferation rates when grown as xenografts <it>in vivo</it>. However, Pim1 expression enhanced the <it>in vitro </it>and <it>in vivo </it>tumorigenic potentials of the human prostate cancer cell lines LNCaP and DU145. Reporter assays revealed increased c-MYC transcriptional activity in Pim1-expressing cells and mRNA expression profiling demonstrated that a large fraction of c-MYC target genes were also regulated by Pim1 expression. The c-MYC inhibitor 10058-F4 suppressed the tumorigenicity of Pim1-expressing prostate cancer cells. Interestingly, 10058-F4 treatment also led to a reduction of Pim1 protein but not mRNA. Knocking-down c-MYC using short hairpin RNA reversed the effects of Pim1 on Pim1/MYC target genes.</p> <p>Conclusion</p> <p>Our results suggest an <it>in vivo </it>role of Pim1 in promoting prostate tumorigenesis although it displayed distinct oncogenic activities depending on the disease stage of the cell line. Pim1 promotes tumorigenicity at least in part by enhancing c-MYC transcriptional activity. We also made the novel discovery that treatment of cells with the c-MYC inhibitor 10058-F4 leads to a reduction in Pim1 protein levels.</p

Vignette studies of medical choice and judgement to study caregivers' medical decision behaviour: systematic review

BACKGROUND: Vignette studies of medical choice and judgement have gained popularity in the medical literature. Originally developed in mathematical psychology they can be used to evaluate physicians' behaviour in the setting of diagnostic testing or treatment decisions. We provide an overview of the use, objectives and methodology of these studies in the medical field. METHODS: Systematic review. We searched in electronic databases; reference lists of included studies. We included studies that examined medical decisions of physicians, nurses or medical students using cue weightings from answers to structured vignettes. Two reviewers scrutinized abstracts and examined full text copies of potentially eligible studies. The aim of the included studies, the type of clinical decision, the number of participants, some technical aspects, and the type of statistical analysis were extracted in duplicate and discrepancies were resolved by consensus. RESULTS: 30 reports published between 1983 and 2005 fulfilled the inclusion criteria. 22 studies (73%) reported on treatment decisions and 27 (90%) explored the variation of decisions among experts. Nine studies (30%) described differences in decisions between groups of caregivers and ten studies (33%) described the decision behaviour of only one group. Only six studies (20%) compared decision behaviour against an empirical reference of a correct decision. The median number of considered attributes was 6.5 (IQR 4-9), the median number of vignettes was 27 (IQR 16-40). In 17 studies, decision makers had to rate the relative importance of a given vignette; in six studies they had to assign a probability to each vignette. Only ten studies (33%) applied a statistical procedure to account for correlated data. CONCLUSION: Various studies of medical choice and judgement have been performed to depict weightings of the value of clinical information from answers to structured vignettes of care givers. We found that the design and analysis methods used in current applications vary considerably and could be improved in a large number of cases

The nuclear receptor LXR modulates interleukin-18 levels through multiple mechanisms

IL-18 is a member of the IL-1 family involved in innate immunity and inflammation. Deregulated levels of IL-18 are involved in the pathogenesis of multiple disorders including inflammatory and metabolic diseases, yet relatively little is known regarding its regulation. Liver X receptors or LXRs are key modulators of macrophage cholesterol homeostasis and immune responses. Here we show that LXR ligands negatively regulate LPS-induced mRNA and protein expression of IL-18 in bone marrow-derived macrophages. Consistent with this being an LXR-mediated process, inhibition is abolished in the presence of a specific LXR antagonist and in LXR-deficient macrophages. Additionally, IL-18 processing of its precursor inactive form to its bioactive state is inhibited by LXR through negative regulation of both pro-caspase 1 expression and activation. Finally, LXR ligands further modulate IL-18 levels by inducing the expression of IL-18BP, a potent endogenous inhibitor of IL-18. This regulation occurs via the transcription factor IRF8, thus identifying IL-18BP as a novel LXR and IRF8 target gene. In conclusion, LXR activation inhibits IL-18 production through regulation of its transcription and maturation into an active pro-inflammatory cytokine. This novel regulation of IL-18 by LXR could be applied to modulate the severity of IL-18 driven metabolic and inflammatory disorders

Probabilistic fire spread forecast as a management tool in an operational setting

Background: An approach to predict fire growth in an operational setting, with the potential to be used as a decision-support tool for fire management, is described and evaluated. The operational use of fire behaviour models has mostly followed a deterministic approach, however, the uncertainty associated with model predictions needs to be quantified and included in wildfire planning and decision-making process during fire suppression activities. We use FARSITE to simulate the growth of a large wildfire. Probabilistic simulations of fire spread are performed, accounting for the uncertainty of some model inputs and parameters. Deterministic simulations were performed for comparison. We also assess the degree to which fire spread modelling and satellite active fire data can be combined, to forecast fire spread during large wildfires events. Results: Uncertainty was propagated through the FARSITE fire spread modelling system by randomly defining 100 different combinations of the independent input variables and parameters, and running the correspondent fire spread simulations in order to produce fire spread probability maps. Simulations were initialized with the reported ignition location and with satellite active fires. The probabilistic fire spread predictions show great potential to be used as a fire management tool in an operational setting, providing valuable information regarding the spatial–temporal distribution of burn probabilities. The advantage of probabilistic over deterministic simulations is clear when both are compared. Re-initializing simulations with satellite active fires did not improve simulations as expected. Conclusion: This information can be useful to anticipate the growth of wildfires through the landscape with an associated probability of occurrence. The additional information regarding when, where and with what probability the fire might be in the next few hours can ultimately help minimize the negative environmental, social and economic impacts of these firesinfo:eu-repo/semantics/publishedVersio