735 research outputs found
Desperately constructing ethnic audiences: Anti-immigration discourses and minority audience research in the Netherlands
This article examines how minority ethnic audiences are measured, and thus constructed, in the Netherlands today. The analysis shows that this process is tightly woven into the dominant assimilationist and neoliberal discourse. This discourse portrays specific minority groups as deviant in relation to an essentialized notion of Dutchness. Furthermore, it presents social inclusion as an opportunity that is limited to well-adjusted, profitable consumers. Different attempts to represent minority audiences β including efforts to promote a more just minority representation in Dutch media β are compelled to accommodate to this dominant discourse. The article underscores the limited scope for contesting current hegemonic representations of minority groups and national belonging in the Netherlands
Anti-proteinase 3 anti-neutrophil cytoplasm autoantibodies recapitulate systemic vasculitis in mice with a humanized immune system.
Evidence is lacking for direct pathogenicity of human anti-proteinase-3 (PR3) antibodies in development of systemic vasculitis and granulomatosis with polyangiitis (GPA, Wegener's granulomatosis). Progress in study of these antibodies in rodents has been hampered by lack of PR3 expression on murine neutrophils, and by different Fc-receptor affinities for IgG across species. Therefore, we tested whether human anti-PR3 antibodies can induce acute vasculitis in mice with a human immune system. Chimeric mice were generated by injecting human haematopoietic stem cells into irradiated NOD-scid-IL2RΞ³β»/β» mice. Matched chimera mice were treated with human IgG from patients with: anti-PR3 positive renal and lung vasculitis; patients with non-vasculitic renal disease; or healthy controls. Six-days later, 39% of anti-PR3 treated mice had haematuria, compared with none of controls. There was punctate bleeding on the surface of lungs of anti-PR3 treated animals, with histological evidence of vasculitis and haemorrhage. Anti-PR3 treated mice had mild pauci-immune proliferative glomerulonephritis, with infiltration of human and mouse leukocytes. In 3 mice (17%) more severe glomerular injury was present. There were no glomerular changes in controls. Human IgG from patients with anti-PR3 autoantibodies is therefore pathogenic. This model of anti-PR3 antibody-mediated vasculitis may be useful in dissecting mechanisms of microvascular injury
Protective effect of human amniotic fluid stem cells in an immunodeficient mouse model of acute tubular necrosis.
Acute Tubular Necrosis (ATN) causes severe damage to the kidney epithelial tubular cells and is often associated with severe renal dysfunction. Stem-cell based therapies may provide alternative approaches to treating of ATN. We have previously shown that clonal c-kit(pos) stem cells, derived from human amniotic fluid (hAFSC) can be induced to a renal fate in an ex-vivo system. Herein, we show for the first time the successful therapeutic application of hAFSC in a mouse model with glycerol-induced rhabdomyolysis and ATN. When injected into the damaged kidney, luciferase-labeled hAFSC can be tracked using bioluminescence. Moreover, we show that hAFSC provide a protective effect, ameliorating ATN in the acute injury phase as reflected by decreased creatinine and BUN blood levels and by a decrease in the number of damaged tubules and apoptosis therein, as well as by promoting proliferation of tubular epithelial cells. We show significant immunomodulatory effects of hAFSC, over the course of ATN. We therefore speculate that AFSC could represent a novel source of stem cells that may function to modulate the kidney immune milieu in renal failure caused by ATN
Tissue Microenvironments Define and Get Reinforced by Macrophage Phenotypes in Homeostasis or during Inflammation, Repair and Fibrosis
Current macrophage phenotype classifications are based on distinct in vitro culture conditions that do not adequately mirror complex tissue environments. In vivo monocyte progenitors populate all tissues for immune surveillance which supports the maintenance of homeostasis as well as regaining homeostasis after injury. Here we propose to classify macrophage phenotypes according to prototypical tissue environments, e.g. as they occur during homeostasis as well as during the different phases of (dermal) wound healing. In tissue necrosis and/or infection, damage- and/or pathogen-associated molecular patterns induce proinflammatory macrophages by Toll-like receptors or inflammasomes. Such classically activated macrophages contribute to further tissue inflammation and damage. Apoptotic cells and antiinflammatory cytokines dominate in postinflammatory tissues which induce macrophages to produce more antiinflammatory mediators. Similarly, tumor-associated macrophages also confer immunosuppression in tumor stroma. Insufficient parenchymal healing despite abundant growth factors pushes macrophages to gain a profibrotic phenotype and promote fibrocyte recruitment which both enforce tissue scarring. Ischemic scars are largely devoid of cytokines and growth factors so that fibrolytic macrophages that predominantly secrete proteases digest the excess extracellular matrix. Together, macrophages stabilize their surrounding tissue microenvironments by adapting different phenotypes as feed-forward mechanisms to maintain tissue homeostasis or regain it following injury. Furthermore, macrophage heterogeneity in healthy or injured tissues mirrors spatial and temporal differences in microenvironments during the various stages of tissue injury and repair. Copyright (C) 2012 S. Karger AG, Base
Intercellular Communication by Exchange of Cytoplasmic Material via Tunneling Nano-Tube Like Structures in Primary Human Renal Epithelial Cells
Transfer of cellular material via tunneling nanotubes (TNT) was recently discovered as a novel mechanism for intercellular communication. The role of intercellular exchange in communication of renal epithelium is not known. Here we report extensive spontaneous intercellular exchange of cargo vesicles and organelles between primary human proximal tubular epithelial cells (RPTEC). Cells were labeled with two different quantum dot nanocrystals (Qtracker 605 or 525) and intercellular exchange was quantified by high-throughput fluorescence imaging and FACS analysis. In co-culture, a substantial fraction of cells (67.5%) contained both dyes indicating high levels of spontaneous intercellular exchange in RPTEC. The double positive cells could be divided into three categories based on the preponderance of 605 Qtracker (46.30%), 525 Qtracker (48.3%) and approximately equal content of both Qtrackers (4.57%). The transfer of mitochondria between RPTECs was also detected using an organelle specific dye. Inhibition of TNT genesis by actin polymerization inhibitor (Latrunculin B) markedly reduced intercellular exchange (>60%) suggesting that intercellular exchange in RPTEC was in part mediated via TNT-like structures. In contrast, induction of cellular stress by Zeocin treatment increased tube-genesis in RPTEC. Our data indicates an unexpected dynamic of intercellular communication between RPTEC by exchange of cytosolic material, which may play an important role in renal physiology
Reversibility of liver fibrosis
Liver fibrosis, and its end stage cirrhosis are a major cause of morbidity and mortality and therapeutic options are limited. However, the traditional view of liver disease as an irreversible process is obsolete and it is now evident that the development of liver fibrosis is a dynamic and potentially bidirectional process. Spontaneous resolution of scarring is seen in animal models of liver fibrosis and in human trials in which the stimuli responsible for chronic or repeated hepatic inflammation is successfully removed. Key players in the process are hepatic stellate cells, macrophages, MMPs and their inhibitors Timps. It is also evident that in advanced fibrotic liver disease, specific histological features define what is currently described as "irreversible" fibrosis. This includes the development of paucicellular scars enriched in extensively cross-linked matrix components, such as fibrillar collagen and elastin. Our recent work has focused on the role of macrophage metalloelastase (MMP-12) in the turnover of elastin in reversible and irreversible models of fibrosis. We have shown that elastin turnover in liver injury and fibrosis is regulated by macrophages via Mmp-12 expression, activity and ratio to its inhibitor Timp-1. Failure of elastin degradation, together with increased deposition leads to accumulation of elastin in the fibrotic scars
Normative data on regional sweat-sodium concentrations of professional male team-sport athletes
Background:
The purpose of this paper was to report normative data on regional sweat sweat-sodium concentrations of various professional male team-sport athletes, and to compare sweat-sodium concentrations among sports. Data to this effect would inform our understanding of athlete sodium requirements, thus allowing for the individualisation of sodium replacement strategies. Accordingly, data from 696 athletes (Soccer, n = 270; Rugby, n = 181; Baseball, n = 133; American Football, n = 60; Basketball, n = 52) were compiled for a retrospective analysis. Regional sweat-sodium concentrations were collected using the pilocarpine iontophoresis method, and compared to self-reported measures collected via questionnaire.
Results:
Sweat-sodium concentrations were significantly higher (p < 0.05) in American football (50.4 Β± 15.3 mmolΒ·L-1), baseball (54.0 Β± 14.0 mmolΒ·L-1), and basketball (48.3 Β± 14.0 mmolΒ·L-1) than either soccer (43.2 Β± 12.0 mmolΒ·L-1) or rugby (44.0 Β± 12.1 mmolΒ·L-1), but with no differences among the N.American or British sports. There were strong positive correlations between sweat-sodium concentrations and self-reported sodium losses in American football (rs = 0.962, p < 0.001), basketball (rs = 0.953, p < 0.001), rugby (rs = 0.813, p < 0.001), and soccer (rs = 0.748, p < 0.001).
Conclusions:
The normative data provided on sweat-sodium concentrations might assist sports science/medicine practitioners in generating bespoke hydration and electrolyte-replacement strategies to meet the sodium demands of professional team-sport athletes. Moreover, these novel data suggest that self-reported measures of sodium loss might serve as an effective surrogate in the absence of direct measures; i.e., those which are more expensive or non-readily available
A Distinct Macrophage Population Mediates Metastatic Breast Cancer Cell Extravasation, Establishment and Growth
Background: The stromal microenvironment and particularly the macrophage component of primary tumors influence their malignant potential. However, at the metastatic site the role of these cells and their mechanism of actions for establishment and growth of metastases remain largely unknown. Methodology/Principal Findings: Using animal models of breast cancer metastasis, we show that a population of host macrophages displaying a distinct phenotype is recruited to extravasating pulmonary metastatic cells regardless of species of origin. Ablation of this macrophage population through three independent means (genetic and chemical) showed that these macrophages are required for efficient metastatic seeding and growth. Importantly, even after metastatic growth is established, ablation of this macrophage population inhibited subsequent growth. Furthermore, imaging of intact lungs revealed that macrophages are required for efficient tumor cell extravasation. Conclusion/Significance: These data indicate a direct enhancement of metastatic growth by macrophages through their effects on tumor cell extravasation, survival and subsequent growth and identifies these cells as a new therapeutic target fo
A caseβcontrol study of selenium in nails and prostate cancer risk in British men
In view of the experimental evidence suggesting that the micronutrient selenium reduces prostate cancer risk, we investigated the association between the selenium level in fingernails, a measure of long-term selenium intake, and prostate cancer risk in a case-control study among 656 British men, conducted in 1989-1992. Nail clippings were taken at the time of recruitment and selenium concentration, measured using neutron activation techniques, was successfully assayed for 300 case-control pairs and varied six-fold among the controls (0.59 p.p.m.; interquartile range, 0.50-0.71 p.p.m.). Nail selenium concentration was not significantly associated with prostate cancer risk: men in the highest quartile of nail selenium had a slightly increased risk compared with men in the lowest quartile (OR 1.24, 95 CI, 0.73-2.10); for advanced prostate cancer, men in the highest quartile had a slightly reduced risk compared with men in the lowest quartile (OR 0.78, 95% CI, 0.27-2.25). These results suggest that selenium is not strongly associated with prostate cancer risk in British men
Pioglitazone Decreases Hepatitis C Viral Load in Overweight, Treatment NaΓ―ve, Genotype 4 Infected-Patients: A Pilot Study
Insulin resistance (IR) is induced by chronic hepatitis C virus (HCV) genotypes 1 and 4 infections. It is not known whether drugs that affect IR such as Pioglitazone and Prednisone also affect serum HCV RNA titers independently of PEG-Interferon-Ξ±2/ribavirin treatment. The primary aim was to assess whether Pioglitazone by improving IR and/or inflammation decreases HCV viral load independently of standard of care HCV treatment. A secondary aim was to assess whether Prednisone, a drug that induces insulin resistance and stimulates HCV viral entry and replication in replicon culture systems, increases HCV viral load in this population.We designed a two-arm, parallel Pilot Study of overweight, treatment naΓ―ve genotype 4 HCV-infected patients at a public referral Liver Clinic in Giza, Egypt. The subjects received Pioglitazone (30 mg/day for 14 days) or Prednisone (40 mg/day for 4 days) in a randomized fashion, but the two arms can be considered independent pilot studies. Only changes from baseline within each arm were assessed and no contrasts of the interventions were made, as this was not an aim of the study. Among 105 consecutive HCV genotype 4 patients, 39 were enrolled based on the optimal sample size and power analysis according to the CONSORT statement; 20 to the Pioglitazone group and 19 to the Prednisone group. Pioglitazone was effective in decreasing serum HCV RNA at day-14 (nβ=β10; difference of meansβ=β205,618 IU/ml; 95% CI 26,600 to 384,600; P<0.001). Although Prednisone did increase serum HCV RNA at day-4 (nβ=β10; change from baselineβ=β-42,786 IU/ml; 95% CI -85,500 to -15,700; Pβ=β0.049), the log(10) HCV RNA titers were statistically not different from baseline day-0.This is the first documentation that Pioglitazone decreases the serum HCV RNA titers independently of PEG-Interferon-Ξ±2/ribavirin treatment. The novel findings of our Study provide the foundation for basic and clinical investigations on the molecular mechanisms responsible for the Pioglitazone-induced decrease in HCV genotype 4 RNA titers.ClinicalTrials.gov NCT01157975
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