Bruhl C.A.,University of Koblenz-Landau |
Pieper S.,Umweltbundesamt |
Weber B.,Harlan Laboratories
Environmental Toxicology and Chemistry | Year: 2011
Current pesticide risk assessment does not specifically consider amphibians. Amphibians in the aquatic environment (aquatic life stages or postmetamorphic aquatic amphibians) and terrestrial living juvenile or adult amphibians are assumed to be covered by the risk assessment for aquatic invertebrates and fish, or mammals and birds, respectively. This procedure has been evaluated as being sufficiently protective regarding the acute risk posed by a number of pesticides to aquatic amphibian life stages (eggs, larvae). However, it is unknown whether the exposure and sensitivity of terrestrial living amphibians are comparable to mammalian and avian exposure and sensitivity. We reviewed the literature on dermal pesticide absorption and toxicity studies for terrestrial life stages of amphibians, focusing on the dermal exposure pathway, that is, through treated soil or direct overspray. In vitro studies demonstrated that cutaneous absorption of chemicals is significant and that chemical percutaneous passage, P (cm/h), is higher in amphibians than in mammals. In vivo, the rapid and substantial uptake of the herbicide atrazine from treated soil by toads (Bufo americanus) has been described. Severe toxic effects on various amphibian species have been reported for field-relevant application rates of different pesticides. In general, exposure and toxicity studies for terrestrial amphibian life stages are scarce, and the reported data indicate the need for further research, especially in light of the global amphibian decline. © 2011 SETAC. Source
Turk M.L.,Massachusetts Institute of Technology |
Cacioppo L.D.,Massachusetts Institute of Technology |
Ge Z.,Massachusetts Institute of Technology |
Shen Z.,Massachusetts Institute of Technology |
And 5 more authors.
Journal of Medical Microbiology | Year: 2012
Helicobacter pullorum, an enterohepatic Helicobacter species, is associated with gastroenteritis and hepatobiliary disease in humans and chickens. Recently, a novel H. pullorum outbreak in barrier-maintained rats and mice was described. In this study, persistence of infection and serological responses were further evaluated in H. pullorum-infected female C57BL/6NTac and C3H/HeNTac mice obtained from the barrier outbreak. C57BL/6NTac mice (n=536) aged 10-58 weeks were confirmed to be chronically infected with H. pullorum by PCR or culture of caecum, colon and faeces, with no evidence of hepatic infection; two of three C3H/HeNTac mice cleared H. pullorum infection by 26 weeks of age. A quantitative PCR (qPCR) assay based on the cdtB gene specific to H. pullorum demonstrated that colonization was high in the caecum and colon at 10 4-10 6 c.f.u. equivalents per μg host DNA, and decreased by several logs from 32 to 58 weeks of age. Infected mice were seropositive by ELISA, and H. pullorum-specific IgG levels decreased as colonization was lost over time in selected mice. Consistent with the lack of pathology associated with chronic infection of C57BL/6 mice with other murine enteric helicobacters, C57BL/6NTac and C3H/HeNTac mice infected with H. pullorum did not develop gross or histological lesions of the liver or gastrointestinal tract. The cdtB-based qPCR assay can be used in screening animals, food sources and environmental samples for H. pullorum, as this food-borne pathogen has zoonotic potential. These findings will also allow future studies in murine models to dissect potential pathogenic mechanisms for this emerging pathogen. © 2012 SGM. Source
Strickland F.M.,University of Michigan |
Hewagama A.,University of Michigan |
Wu A.,University of Michigan |
Sawalha A.H.,University of Michigan |
And 9 more authors.
Arthritis and Rheumatism | Year: 2013
Objective Lupus flares occur when genetically predisposed individuals encounter appropriate environmental agents. Current evidence indicates that the environment contributes by inhibiting T cell DNA methylation, causing overexpression of normally silenced genes. DNA methylation depends on both dietary transmethylation micronutrients and ERK-regulated DNA methyltransferase 1 (DNMT-1) levels. We used transgenic mice to study the effect of interactions between diet, DNMT-1 levels, and genetic predisposition on the development and severity of lupus. Methods A doxycycline-inducible ERK defect was bred into lupus-resistant (C57BL/6) and lupus-susceptible (C57BL/6 × SJL) mouse strains. Doxycycline-treated mice were fed a standard commercial diet for 18 weeks and then switched to a transmethylation micronutrient-supplemented (MS) or -restricted (MR) diet. Disease severity was assessed by examining anti-double-stranded DNA (anti-dsDNA) antibody levels, the presence of proteinuria and hematuria, and by histopathologic analysis of kidney tissues. Pyrosequencing was used to determine micronutrient effects on DNA methylation. Results Doxycycline induced modest levels of anti-dsDNA antibodies in C57BL/6 mice and higher levels in C57BL/6 × SJL mice. Doxycycline-treated C57BL/6 × SJL mice developed hematuria and glomerulonephritis on the MR and standard diets but not the MS diet. In contrast, C57BL/6 mice developed kidney disease only on the MR diet. Decreasing ERK signaling and methyl donors also caused demethylation and overexpression of the CD40lg gene in female mice, consistent with demethylation of the second X chromosome. Both the dietary methyl donor content and the duration of treatment influenced methylation and expression of the CD40lg gene. Conclusion Dietary micronutrients that affect DNA methylation can exacerbate or ameliorate disease in this transgenic murine lupus model, and contribute to lupus susceptibility and severity through genetic-epigenetic interactions. Copyright © 2013 by the American College of Rheumatology. Source
Onnheim K.,Gothenburg University |
Ekblad M.,Gothenburg University |
Gorander S.,Gothenburg University |
Lange S.,Gothenburg University |
And 4 more authors.
Archives of Virology | Year: 2015
In this study we describe that six rat models (SD, WIST, LEW, BN, F344 and DA) are susceptible to intravaginal herpes simplex virus-2 (HSV-2) infection after pre-treatment with progesterone. At a virus dose of 5 × 106 PFU of HSV-2, all rat models were infected presenting anti-HSV-2 antibodies, infectious virus in vaginal washes, and HSV-2 DNA genome copies in lumbosacral dorsal root ganglia and the spinal cord. Most of the LEW, BN, F344, and DA rats succumbed in systemic progressive symptoms at day 8-14 post infection, but presented no or mild genital inflammation while SD and WIST rats were mostly infected asymptomatically. Infected SD rats did not reactivate HSV-2 spontaneously or after cortisone treatment. In an HSV-2 virus dose reduction study, F344 rats were shown to be most susceptible. We also investigated whether an attenuated HSV-1 strain (KOS321) given intravaginally, could protect from a subsequent HSV-2 infection. All LEW, BN, and F344 rats survived a primary HSV-1 infection and no neuronal infection was established. In BN and F344 rats, anti-HSV-1 antibodies were readily detected while LEW rats were seronegative. In contrast to naïve LEW, BN, and F344 rats where only 3 of 18 animals survived 5 × 106 PFU of HSV-2, 23 of 25 previously HSV-1 infected rats survived a challenge with HSV-2. The described models provide a new approach to investigate protective effects of anti-viral microbicides and vaccine candidates, as well as to study asymptomatic primary genital HSV-2 infection. © 2015, Springer-Verlag Wien. Source
Da Costa Martins P.A.,Hubrecht Institute and Interuniversity Cardiology |
Da Costa Martins P.A.,Maastricht University |
Salic K.,Hubrecht Institute and Interuniversity Cardiology |
Salic K.,Maastricht University |
And 15 more authors.
Nature Cell Biology | Year: 2010
MicroRNAs (miRs) are a class of single-stranded, non-coding RNAs of about 22 nucleotides in length. Increasing evidence implicates miRs in myocardial disease processes. Here we show that miR-199b is a direct calcineurin/NFAT target gene that increases in expression in mouse and human heart failure, and targets the nuclear NFAT kinase dual-specificity tyrosine-(Y)-phosphorylation regulated kinase 1a (Dyrk1a), constituting a pathogenic feed forward mechanism that affects calcineurin-responsive gene expression. Mutant mice overexpressing miR-199b, or haploinsufficient for Dyrk1a, are sensitized to calcineurin/NFAT signalling or pressure overload and show stress-induced cardiomegaly through reduced Dyrk1a expression. In vivo inhibition of miR-199b by a specific antagomir normalized Dyrk1a expression, reduced nuclear NFAT activity and caused marked inhibition and even reversal of hypertrophy and fibrosis in mouse models of heart failure. Our results reveal that microRNAs affect cardiac cellular signalling and gene expression, and implicate miR-199b as a therapeutic target in heart failure. © 2010 Macmillan Publishers Limited. All rights reserved. Source