392 research outputs found

    Helicobacter hepaticus cytolethal distending toxin promotes intestinal carcinogenesis in 129Rag2‐deficient mice

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    Multiple pathogenic Gram-negative bacteria produce the cytolethal distending toxin (CDT) with activity of DNase I; CDT can induce DNA double-strand breaks (DSBs), G2/M cell cycle arrest, and apoptosis in cultured mammalian cells. However, the link of CDT to in vivo tumorigenesis is not fully understood. In this study, 129/SvEv Rag2−/−mice were gavaged with wild-type Helicobacter hepatics 3B1(Hh) and its isogenic cdtB mutant HhcdtBm7, followed by infection for 10 and 20 weeks (WPI). HhCDT deficiency did not affect cecal colonization levels of HhcdtBm7, but attenuated severity of cecal pathology in HhcdtBm7-infected mice. Of importance, preneoplasic dysplasia was progressed to cancer from 10 to 20 WPI in the Hh-infected mice but not in the HhcdtBm7-infected mice. In addition, the loss of HhCDT significantly dampened transcriptional upregulation of cecal Tnfα and Il-6, but elevated Il-10 mRNA levels when compared to Hh at 10 WPI. Furthermore, the presence of HhCDT increased numbers of lower bowel intestinal ÎłH2AX-positive epithelial cells (a marker of DSBs) at both 10 and 20 WPI and augmented phospho-Stat3 foci[superscript +] intestinal crypts (activation of Stat3) at 20 WPI. Our findings suggest that CDT promoted Hh carcinogenesis by enhancing DSBs and activation of the Tnfα/Il-6-Stat3 signaling pathway.National Institutes of Health (U.S.) (Grant R01-OD01141)National Institutes of Health (U.S.) (Grant T32-OD010978)National Institutes of Health (U.S.) (Grant P01 CA28842

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    Abstract Helicobacter pylori infection promotes male-predominant gastric adenocarcinoma in humans. Estrogens reduce gastric cancer risk and previous studies demonstrated that prophylactic 17ÉŽ-estradiol (E2) in INS-GAS mice decreases H. pylori-induced carcinogenesis. We examined the effect of E2 and Tamoxifen, on H. pylori-induced gastric cancer in male and female INS-GAS mice. After confirming robust gastric pathology at 16 weeks post-infection (WPI), mice were implanted with E2

    A new fireworm (Amphinomidae) from the Cretaceous of Lebanon identified from three-dimensionally preserved myoanatomy

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    © 2015 Parry et al. Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. The attached file is the published version of the article

    Gut bacteria require neutrophils to promote mammary tumorigenesis

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    Recent studies suggest that gastrointestinal tract microbiota modulate cancer development in distant non-intestinal tissues. Here we tested mechanistic hypotheses using a targeted pathogenic gut microbial infection animal model with a predilection to breast cancer. FVB-Tg(C3-1-TAg)cJeg/JegJ female mice were infected by gastric gavage with Helicobacter hepaticus at three-months-of-age putting them at increased risk for mammary tumor development. Tumorigenesis was multifocal and characterized by extensive infiltrates of myeloperoxidase-positive neutrophils otherwise implicated in cancer progression in humans and animal models. To test whether neutrophils were important in etiopathogenesis in this bacteria-triggered model system, we next systemically depleted mice of neutrophils using thrice weekly intraperitoneal injections with anti-Ly-6G antibody. We found that antibody depletion entirely inhibited tumor development in this H. hepaticus-infected model. These data demonstrate that host neutrophil-associated immune responses to intestinal tract microbes significantly impact cancer progression in distal tissues such as mammary glands, and identify gut microbes as novel targets for extra-intestinal cancer therapy.National Institutes of Health (U.S.) (Grant U01 CA164337)National Institutes of Health (U.S.) (Grant T32 OD011141

    The relationships between seedling root screens, root growth in the field and grain yield for wheat

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    Background and aims We were interested to know if laboratory screens of root growth could be used to predict root performance and grain yield of wheat when grown in the field. A secondary aim of this work was to explore the relationship between root depth and grain yield. Methods We screened 637 wheat lines, composed of elite as well as a limited number of breeding lines, to identify wheat lines with contrasting young root traits with a high throughput screen. We selected groups of wheat lines based on the size of the seedling root, root diameter and growth angle. Seventy-two wheat lines were subjected to further screening with a wax-layer screen and grown in a field experiment in two successive years. Root length distributions, from field grown wheat, were determined with the core-break method. Results We were unable to find relationships between data from the laboratory root screens and root depth in the field. In the field, wheat lines with deep roots always had high grain yields, but deep roots were not essential to obtain high yields. Wheat lines with the deepest roots were also amongst those with the greatest number of shallow roots. Conclusion Laboratory root screens did not predict root depth in the field. Root diameter, for reasons that are not clear, is correlated with high grain yield

    Magnetic resonance imaging in patients with meningitis induced hearing loss

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    The aim of this multicentre study was to compare T1 with T2 weighted MRI scans of the labyrinth after meningitis and to investigate whether waiting with scanning improved the reliability of diagnosing an ongoing process such as cochlear osteogenesis. Forty-five patients were included who suffered from meningitis induced hearing loss (radiological imaging <1 year after meningitis). Twenty-one gadolinium enhanced T1 and 45 T2 weighted MRI scans were scored by two radiologists regarding the condition of the labyrinth. These radiological observations were compared with the condition of the cochlea as described during cochlear implantation. A higher percentage of agreement with surgery was found for T2 (both radiologists 73%) than for T1 weighted MRI scans (radiologist 1: 62%, radiologist 2: 67%), but this difference is not significant. There was no significant difference between early (0–3 months) and late (>3 months) scanning, showing that radiological imaging soon after meningitis allows early diagnosis without suffering from a lower agreement with surgical findings
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