Swiss Rolls Research Articles

Whole Abdominal Pencil Beam Scanned Proton FLASH Increases Acute Lethality

PurposeUltra-high dose-rate FLASH radiotherapy (RT) has emerged as a modality which promises to reduce normal tissue toxicity while maintaining tumor control. Previous studies of gastrointestinal toxicity using passively scattered FLASH proton therapy (PRT) have, however, yielded mixed results, suggesting that the requirements for gastrointestinal sparing by FLASH are an open question. Furthermore, the more clinically relevant pencil beam scanned (PBS) FLASH PRT has not yet been assessed in this context, despite differences in the spatiotemporal dose-rate distributions compared to passively scattered PRT. Here, we provide the first report on the effects of PBS FLASH PRT on acute gastrointestinal injury in mice after whole abdominal irradiation. Methods and MaterialsWhole abdominal irradiation was performed on C57BL/6J mice using the entrance channel of the Bragg curve of a 250 MeV PBS proton beam at field-averaged dose-rates of 0.6 Gy/s for conventional (CONV) and 80-100 Gy/s for FLASH PRT. A 2D strip ionization chamber array was used to measure the dose and dose rate for each mouse. Survival was assessed at 14 Gy. Intestines were harvested and processed as Swiss rolls for analysis using a novel artificial intelligence (AI)-based crypt assay to quantify crypt regeneration 4 days post-irradiation. ResultsSurvival was significantly reduced following 14 Gy FLASH PRT compared to CONV (P<0.001). Our AI-based crypt assays demonstrated no significant difference in intestinal crypts/cm or crypt depth between groups 4 days post-irradiation. Furthermore, we found no significant difference in EdU+ cells/crypt or Olfactomedin4+ intestinal stem cells with FLASH relative to CONV PRT. ConclusionsOverall, our data demonstrate significantly impaired survival following abdominal PBS FLASH PRT without apparent differences in intestinal histology 4 days post-irradiation.

Optimized Protocol for Intestinal Swiss Rolls and Immunofluorescent Staining of Paraffin Embedded Tissue.

The intestine is a complex organ composed of the small and the large intestines. The small intestine can be further divided into duodenum, jejunum, and ileum. Each anatomical region of the intestine has a unique function that is reflected by differences in cellular structure. Investigating changes in the intestine requires an in-depth analysis of different tissue regions and cellular alterations. To study the intestine and visualize large pieces of tissue, researchers commonly use a technique known as intestinal Swiss rolls. In this technique, the intestine is divided into each anatomical region and fixed in a flat orientation. Then, the tissue is carefully rolled and processed for paraffin embedding. Proper tissue fixation and orientation is an often-overlooked laboratory technique but is critically important for downstream analysis. Additionally, improper Swiss rolling of intestinal tissue can damage the fragile intestinal epithelium, leading to poor tissue quality for immunostaining. Ensuring well-fixed and properly oriented tissue with intact cellular structures is a crucial step that ensures optimal visualization of intestinal cells. We present a cost-effective and simple method for making Swiss rolls to include all sections of the intestine in a single paraffin-embedded block. We also describe optimized immunofluorescence staining of intestinal tissue to study various aspects of the intestinal epithelium. The following protocol provides researchers with a comprehensive guide to obtaining high-quality immunofluorescence images through intestinal tissue fixation, Swiss-roll technique, and immunostaining. Employing these refined approaches preserves the intricate morphology of the intestinal epithelium and fosters a deeper understanding of intestinal physiology and pathobiology.

ACONITATE DECARBOXYLASE 1 IS A KEY REGULATOR OF COLITIS

Abstract INTRODUCTION Aconitate decarboxylase 1 (ACOD1; also known as IRG1) is highly expressed in activated macrophages and converts cis-aconitate to itaconate, which contributes to the antimicrobial activity of macrophages. The role of ACOD1 in intestinal inflammation remains unknown. Therefore, we investigated the role of ACOD1 during colitis induced by Citrobacter rodentium (C. rodentium), a murine bacterial pathogen used to model the pathogenesis of enteropathogenic Escherichia coli, and dextran sulfate sodium (DSS) a model of epithelial injury-mediated inflammation. METHODS The GEO database was utilized to examine ACOD1 mRNA levels in ulcerative colitis (UC) and Crohn’s disease (CD) patients, and normal controls. C57BL/6 wild-type (WT) and Acod1–/– mice were infected with C. rodentium for 14 days or given 4% DSS for 5 days and then normal drinking water for 5 days. Mice were weighed daily. Histology was analyzed by H&amp;E staining on colon Swiss rolls using a 0-21 scale for C. rodentium infection and a 0-40 scale for DSS. DNA was extracted from stool to use for 16S microbiome analysis from 5 naïve WT and 5 Acod1–/– mice. RESULTS ACOD1 expression is increased in the colon of UC and CD patients compared to normal controls (GEO GSE16879). Further ACOD1 is significantly increased in active UC compared to inactive (P=0.0256) (GEO GSE75214). C. rodentium-infected Acod1–/– mice lost significantly more body weight compared to infected WT mice (P&amp;lt;0.0001). There was a significant increase in histologic injury score in the infected Acod1–/– mice (12.07 ± 0.93; n=19) compared to infected WT mice (7.65 ± 1.04; n=20; P=0.0087). In the DSS model, we observed a significant decrease in body weight (P=0.0002) in Acod1–/– mice compared to controls. A significant decrease in colon length, commonly associated with colitis in mice, was observed in the DSS-treated Acod1–/– animals (6.07 ± 0.29 cm compared to 7.22 ± 0.32 cm; P=0.0164). This was accompanied by a significant increase in histologic injury score (23.89 ± 2.14) compared to treated WT mice (13.47 ± 2.03; P=0.0004), which was driven by inflammation, epithelial injury, and crypt damage. 16S microbiome analysis on naïve mice from each genotype revealed significant differences in both the phylum and genus. Acod1–/– mice had significantly more Bacteroidetes (P=0.03) and Proteobacteria (P=0.03), specifically more Alloprevotella (P=0.029) and Prevotellaceae (P=0.029). CONCLUSION While ACOD1 is increased in human IBD tissues, our data indicates that this enzyme has a protective role in experimental colitis. Notably, Acod1 deletion is associated with an altered microbiome. Together our findings suggest that enhancement of ACOD1 activity may represent a new therapeutic strategy for IBD.

A Novel PAK1-Notch1 Axis Regulates Crypt Homeostasis in Intestinal Inflammation.

Background & Aimsp21-activated kinase-1 (PAK1) belongs to a family of serine-threonine kinases and contributes to cellular pathways such as nuclear factor-κB (NF-κB), mitogen-activated protein kinase (MAPK), phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT), and Wingless-related integration site(Wnt)/β-catenin, all of which are involved in intestinal homeostasis. Overexpression of PAK1 is linked to inflammatory bowel disease as well as colitis-associated cancer (CAC), and similarly was observed in interleukin (IL)10 knockout (KO) mice, a model of colitis and CAC. Here, we tested the effects of PAK1 deletion on intestinal inflammation and carcinogenesis in IL10 KO mice.MethodsIL10/PAK1 double-knockout (DKO) mice were generated and development of colitis and CAC was analyzed. Large intestines were measured and prepared for histology or RNA isolation. Swiss rolls were stained with H&E and periodic acid-Schiff. Co-immunoprecipitation and immunofluorescence were performed using intestinal organoids, SW480, and normal human colon epithelial cells 1CT.ResultsWhen compared with IL10 KO mice, DKOs showed longer colons and prolonged crypts, despite having higher inflammation and numbers of dysplasia. Crypt hyperproliferation was associated with Notch1 activation and diminished crypt differentiation, indicated by a reduction of goblet cells. Gene expression analysis indicated up-regulation of the Notch1 target hairy and enhancer of split-1 and the stem cell receptor leucin-rich repeat-containing G-protein–coupled receptor 5 in DKO mice. Interestingly, the stem cell marker olfactomedin-4 was present in colonic tissue. Increased β-catenin messenger RNA and cytoplasmic accumulation indicated aberrant Wnt signaling. Co-localization and direct interaction of Notch1 and PAK1 was found in colon epithelial cells. Notch1 activation abrogated this effect whereas silencing of PAK1 led to Notch1 activation.ConclusionsPAK1 contributes to the regulation of crypt homeostasis under inflammatory conditions by controlling Notch1. This identifies a novel PAK1–Notch1 axis in intestinal pathophysiology of inflammatory bowel disease and CAC.

Cloaking In-Plane Elastic Waves with Swiss Rolls.

We propose a design of cylindrical cloak for coupled in-plane shear waves consisting of concentric layers of sub-wavelength resonant stress-free inclusions shaped as Swiss rolls. The scaling factor between inclusions’ sizes is according to Pendry’s transform. Unlike the hitherto known situations, the present geometric transform starts from a Willis medium and further assumes that displacement fields in original medium and in transformed medium remain unaffected (). This breaks the minor symmetries of the rank-4 and rank-3 tensors in the Willis equation that describe the transformed effective medium. We achieve some cloaking for a shear polarized source at specific, resonant sub-wavelength, frequencies, when it is located in close proximity to a clamped obstacle surrounded by the structured cloak. The structured medium approximating the effective medium allows for strong Willis coupling, notwithstanding potential chiral elastic effects, and thus mitigates roles of Willis and Cosserat media in the achieved elastodynamic cloaking.

Tuft cells: Distribution and connections with nerves and endocrine cells in mouse intestine

Tuft cells are gastrointestinal (GI) sensory cells recognized by their characteristic shape and their microvilli “tuft”. Aims of the present study were to elucidate their regional distribution and spatial connections with satiety associated endocrine cells and nerve fibers throughout the intestinal tract. C57BL/6 J mice were used in the experiments. The small intestine was divided into five segments, and the large intestine was kept undivided. The segments were coiled into “Swiss rolls”. Numbers and topographic distribution of tuft cells and possible contacts with endocrine cells and nerve fibers were estimated in the different segments, using immunocytochemistry. Tuft cells were found throughout the intestines; the highest number was in proximal small intestine. Five percent of tuft cells were found in close proximity to cholecystokinin-immunoreactive (IR) endocrine cells and up to 10% were in contact with peptide YY- and glucagon-like peptide-1-IR endocrine cells. Sixty percent of tuft cells in the small intestine and 40% in the large intestine were found in contact with nerve fibers. Calcitonin gene-related peptide-IR fibers constituted one-third of the fiber-contacts in the small intestine and two-thirds in the large intestine. These observations highlight the possibility of tuft cells as modulators of GI activities in response to luminal signaling.

Abstract A49: Using IL10-/- mouse model to assess heavy-ion radiation exposure-associated colitis and colorectal cancer incidence

Abstract Underlying risk of γ-ray-induced colitis and colorectal cancer incidence is emphasized by the studies on atom bomb survivors and also in patients undergoing radiotherapy. However, uncertainties in colitis and CRC risk prediction after exposure to high-LET space (particle) radiation exposure has not been realized due to lack of reliable in vivo data. Here we report IL10-/- mice as a suitable mouse model for assessment of colitis and CRC risk after exposure to space radiation. Male mice (n=12 mice/group) were whole-body exposed to sham-radiation, γ-rays (137Cs-source, 2.0 Gy), and 28Si-ion (300 MeV/n; 70 keV/μm; 1.4 Gy). We used γ-ray equitoxic doses using relative biologic effectiveness (RBE) values determined earlier. Mice were sacrificed 90 days after irradiation, and colon swiss rolls were prepared and histopathologic assessment of colitis score and CRC grade was noted. Further, inflammation-associated gene-expression analysis was conducted in both radiation-induced tumor and adjoining normal tissue area. Immunohistochemistry (β-catenin, Cyclin-D1, and phospho-histone H3) was also performed to assess HZE-induced proliferative signaling. Relative to controls and γ-ray, colitis score, colon tumor incidence, size, and grade were significantly higher after space (28Si-ion) radiation exposure. Additionally, tumor incidence per unit of radiation (per cGy) was also higher after 28Si-ion radiation relative to γ radiation. Higher number of phospho-histone H3-positive cells in 28Si-ion exposed mouse colon demonstrated increased proliferative index resulting in increased intestinal tumors of larger size and grade was due to greater activation of β-catenin and its downstream effector cyclin D1. Inflammatory gene signature was more pronounced after 28Si-ion exposure. Significant upregulation of GATA4, ICAM1, ITGA2, and EGFR was exclusive to 28Si-ion exposed mouse colon; however, PTGES and TGFβ1 were upregulated in both γ and 28Si-ion exposed mice. Overall, our findings suggest that IL10-/- mice are a suitable model to assess IR-induced colitis and CRC risk and space radiation carries higher risk of colitis and CRC incidence, relative to γ-rays at comparable doses. This study has implications for risk prediction in astronauts planning for deep-space missions and also for cancer patients planning to undergo particle radiotherapy. Citation Format: Shubhankar Suman, Bo-Hyun Moon, Albert J. Fornace, Jr., Kamal Datta. Using IL10-/- mouse model to assess heavy-ion radiation exposure-associated colitis and colorectal cancer incidence [abstract]. In: Proceedings of the AACR Special Conference: Advances in Modeling Cancer in Mice: Technology, Biology, and Beyond; 2017 Sep 24-27; Orlando, Florida. Philadelphia (PA): AACR; Cancer Res 2018;78(10 Suppl):Abstract nr A49.

Abstract A03: Determining the role of Vitamin D Receptor (VDR) and Retinoid X Receptor Alpha (RXRα) in colitis

Abstract A03: Determining the role of Vitamin D Receptor (VDR) and Retinoid X Receptor Alpha (RXRα) in colitis

A novel PAK1/Notch-1 axis contributes to intestinal inflammation and cancer

Background: PAK1 belongs to a family of serine-threonine kinase and contributes to various oncogenic pathways like MAPK and Wnt-β catenin. Our lab recently linked activation of p21-activated kinase (PAK1) to IBD as well as colitis-associated cancer (Khare V, Inflamm Bowel Dis 2015). Here we tested the effects of PAK1 deletion on intestinal inflammation and carcinogenesis in IL-10 KO mice. Methods: IL-10 KO mice were crossed with Pak1 KO mice to generate double-knockout mice (DKO). Inflammation was triggered with piroxicam (200ppm mixed to chow for 14 d). After 12 wks mice were euthanized, intestines were prepared and length was measured. Paraffin embedded Swiss rolls were stained with HE MAPK pathway activation, as shown by increased pERK1/2 staining and an increase in γH2AX positive nuclei, indicating more DNA double-strand breaks. A reduced differentiation of goblet cells and Paneth cells was marked by PAS- and Lysozyme staining, together with an expansion of the stem cell compartment (shown by increased activated Notch1 and LGR5 staining) in the colonic crypts of DKOs. Interestingly NFκB was found to be reduced in DKO mice. Conclusion: Our data suggest a novel interaction of PAK-1 with the Notch pathway in regulating crypt cell stemness, proliferation and differentiation. Lack of mature goblet cells and mucus can exacerbate colitis in IL-10 KO mice. Hyperproliferation may promote dysplastic lesions independent of NFκB.

Metallic strip gratings in the sub-subwavelength regime.

Metallic strip gratings (MSG) have different applications, ranging from printed circuits to filters in microwave domains. When they are under the influence of an electromagnetic field, evanescent and/or abnormal modes appear in the region between the traces, their utilization leading to the development of new electromagnetic nondestructive evaluation methods. This paper studies the behavior of MSGs in the sub-subwavelength regime when they are excited with TEz or TMz polarized plane waves and the slits are filled with different dielectrics. The appearance of propagating, evanescent and abnormal modes is emphasized using an electromagnetic sensor with metamaterials lens realized with two conical Swiss rolls, which allows the extraction of the information carried by the guided evanescent waves. The evanescent waves, manipulated by the electromagnetic sensor with metamaterial lenses, improve the electromagnetic images so that a better spatial resolution is obtained, exceeding the limit imposed by diffraction. Their theoretical and experimental confirmation opens the perspective for development of new types of sensors working in radio and microwave frequencies.

409 The Colonic Adherent-Invasive Escherichia coli Strain HM605 Induces Anti-Apoptotic Responses in Intestinal Epithelial Cells, Reduces Barrier Integrity and Worsens Experimental Colitis

G A A b st ra ct s (MMPs) are zinc-dependent neutral endopeptidases that participate in degradation of extracellular matrix proteins involved in a variety of pathological processes including inflammation and cancer. MMP9 protein expression and activity is undetectable in most healthy adult tissues including the intestine but is highly expressed in inflammatory state. We have shown that despite being a mediator of acute inflammation MMP9 plays a protective role in the development of CAC. Aim of the present study is to determine the necessity and sufficiency of epithelial derived MMP9 mediated p53 activation via Notch1 signaling for its tumor suppressive function in CAC, by using MMP9 transgenic mice (Tg-villin-MMP9) that specifically overexpresses MMP9 in the colonic epithelium. Methods: Age and gender matched Tg-villin-MMP9 and their wild type littermates (WT) mice were used for in vivo experiments and embryonic fibroblasts (MEFs) isolated from WT and MMP9-/mice were used for in vitro experiments. Mice were exposed to dextran sulfate sodium (DSS, 3% in drinking water) and were given 3 DSS cycles of one week each and with two weeks apart and were sacrificed at day 75. Colons were processed for inflammation and polyps. Swiss rolls of colonic tissues were histologically examined. Western blot (WB) analysis was done with the colonic mucosal stripping. Results: Tg-villin-MMP9 mice were more resistant to CAC as evidenced by decreased tumor burden. In addition, decreased erosion of mucosal layer, infiltration of neutrophils and dysplasia were seen in the polyps of Tg-villin-MMP9 mice compared to WTs both inducedwith CAC.WB analysis indicated significantly increased protein expression of NICD (active Notch1), p53, p21WAF1/Cip1, Bax-1 and caspase-3 compared to WTs mice both induced with CAC. TUNEL staining showed increased apoptosis in the colons of Tg-villin-MMP9 mice compared to WTs mice both induced with CAC. MMP9 overexpression (by stable transfection) in MMP9-/MEFs resulted in significantly increased protein expression of NICD, p53 and p21WAF1/Cip1 expressions compared to non-transfected MMP9-/MEFs, and were comparable to WT MEFs. Conclusion: Together, the data show that constitutive expression of MMP9 in colonic epithelium modulates apoptosis and cell cycle arrest, and thereby acts as a tumor suppressor in CAC. This study elucidates the novel tumor suppressive role of MMP9 in malignant transformation of the colonic epithelium in context of chronic inflammation which may provide new diagnostic and therapeutic approaches.

Electromagnetic metamaterials

This paper proposes a review of electromagnetic metamaterials based on the idea that these are composite materials, their properties depending of the type and dimensions of the structural elements as well as the dimensions of unit cell. From the multitude of structural elements, only few that could present negative permittivity and negative or very high permeability in the range of radio and microwave frequency were chosen. The method of determination for the constitutive parameters ( μ eff and ɛ eff ) of metamaterials based on the S parameters or transmission and reflection coefficients is presented. Moreover, some applications of metamaterials are described, the attention being focused on perfect lenses and novel structures, namely conical Swiss rolls, electromagnetic cloaks and sensors for nondestructive evaluation of materials. Given that the spatial resolution of these sensors can be substantially improved in comparison to classical sensors, the metamaterial lenses are used for the manipulation of evanescent waves.

Abstract 176: Thymoquinone attenuates tumor development in a mouse model of Lynch syndrome.

Abstract Background: Hereditary nonpolyposis colorectal cancer (HNPCC, Lynch syndrome) is caused by germline mutations of DNA mismatch repair proteins leading to microsatellite instability (MSI). Nigella sativa oil has known antitumorigenic effects and was identified in an in vitro screen for compounds that reduce microsatellite instability (C. Campregher, unpublished data). Here we used a mouse model for HNPCC (Villin-Cre Msh2loxP/loxP) to test the effect of thymoquinone (TQ), the active ingredient of Nigella sativa oil, on intestinal tumor development. Methods: 60 mice (20 per group) were treated for 10 months with chow containing TQ-low (37.5 mg/kg diet), TQ-high (375 mg/kg diet) or regular mouse chow. Serial tissue sections of paraffin embedded Swiss rolls of the entire intestine were H&amp;E stained and analyzed for tumor multiplicity, incidence and size. As tumor multiplicity in these mice is generally low (1-2 tumors/mouse) serial sections were prepared from the upper-, middle- and lower part of the paraffin block. Tumor size was scored as small, medium or large according to its presence on 1, 2 or all 3 sections of the block. DNA was isolated from microdissected normal intestinal and tumor tissue and tested for MSI by fragment analysis using a panel of six markers (Kabbarah 2003). Data were quantitated as nucleotide shift per marker (NSPM) and compared to germline DNA from mouse tails. Results: Treatment with TQ-low and TQ-high resulted in a significant reduction of tumor incidence from 94.4% to 57.9% (p&amp;lt;0.01) and 55.0% (p&amp;lt;0.006), respectively. TQ-low and TQ-high also reduced tumor multiplicity from 3.1 to 1.4 (p=0.003) and to 0.9 (p&amp;lt;0.001), respectively. The number of small and medium sized tumors was reduced in both treatment groups. The number of large tumors was not affected. Fragment analysis demonstrated global MSI in normal intestinal epithelial cells (on average 1.8 NSPM). TQ-low and TQ-high reduced the global MSI in normal intestinal epithelial cells to 0.9 and 0.9 NSPM, respectively. Tumor DNA displayed generally higher MSI than normal intestinal epithelial cells (2.7, 2.5, and 1.5 NSPM for control mice, TQ-low, and TQ-high, respectively) and was only reduced by TQ-high. Conclusion: In this mouse model of HNPCC TQ reduces the tumor incidence and tumor multiplicity by increasing replication fidelity in the Msh2-deficient intestinal epithelial cells. We propose TQ as a candidate compound for prevention of colorectal cancer in carriers of HNPCC mutations. Citation Format: Benedikt Kortüm, Christoph Campregher, Matthias Pinter, Michaela Lang, Rayko Evstatiev, Vineeta Khare, Melanie H. Kucherlapati, Winfried Edelmann, Christoph Gasche. Thymoquinone attenuates tumor development in a mouse model of Lynch syndrome. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 176. doi:10.1158/1538-7445.AM2013-176

P110 Surveillance for colorectal cancer in colitis patients: effect of the implementation of new British and American guidelines on neoplasia yield

Background: Mutations in the IL-10 and IL-10 receptor genes are associated with early onset of IBD. Patients with IBD have a higher risk of developing colorectal cancer. Also mice deficient in IL-10 develop spontaneous enterocolitis and colitis-associated cancer (CAC) and may serve as model to study CAC in humans. The mutational mechanisms of cancer development and neoplastic progression in IL-10-/mice, however, remain unclear (Sturlan, Carcinogenesis 2001). Methods: Seven week old C57BL/6 IL-10-/mice received either 200 ppm piroxicam for 7 days as part of their chow (n=43) or plain chow (n=45). After 30 weeks mice were euthanized, the intestine was dissected, coiled as Swiss rolls and inflammation was scored according to Berg et al. (Cell 1996) with a scale from 0 to 4. Immunohistochemistry was performed for 8-oxoguanine (8-oxoG) to identify oxidative DNA lesions and for phosphohistone H2AX (γH2AX) to evaluate DNA double-strand breaks (DSB). The induction of DSB repair was assessed by staining for MRE11, homologous recombination by BRCA1 and nonhomologous end joining (NHEJ) by Ku70. Apoptosis was detected by TUNEL assay. Global methylation status was assessed by analysis of the CpG islands within the B1 element. LOH fragment analysis of micro-dissected tissue is currently performed (data will be available at the meeting). Results: Mice in both groups developed colitis. The average inflammation grade was 2.86 ± 0.64 (95%CI=2.663.06) and 1.8 ± 0.82 (95%CI=1.562.04) for the piroxicam and the control group, respectively (p,0.001). 13/43 piroxicam-treated mice developed 22 invasive tumors (max. 5 per mouse) compared to 3/45 mice with 6 tumors (max. 4 per mouse) in the control group (p=0.004). In both groups, the number of invasive tumors increased with the severity of inflammation (R= 0.539, p ,0.001). 8-oxoG also increased with a higher inflammation score (R=0.923, p,0.001). γH2AX positive cells were found in crypts and the intermediate zone and varied with disease progression (19.6% γH2AX positivity in non-inflamed, 37.7% in inflamed, and 45.7% in invasive tumors, respectively; p,0.001) and inflammation (R=0.858, p,0.001). γH2AX staining was coupled with overexpression of MRE11, BRCA1 and most pronounced with Ku70 indicating presence of DSB with activation of NHEJ. Apoptosis and global methylation were not induced in this model of CAC. Conclusion: Piroxicam treatment increases intestinal inflammation and tumorigenesis in IL-10-/mice. Progression of inflammation to cancer is associated with oxidative DNA damage and the overt presence of DSB. We propose that the persistent upregulation of error-prone NHEJ is a mechanism of chromosomal instability in this model of CAC.

Structural, functional and molecular analysis of the effects of aging in the small intestine and colon of C57BL/6J mice

BackgroundBy regulating digestion and absorption of nutrients and providing a barrier against the external environment the intestine provides a crucial contribution to the maintenance of health. To what extent aging-related changes in the intestinal system contribute to the functional decline associated with aging is still under debate.MethodsYoung (4 M) and old (21 M) male C57BL/6J mice were fed a control low-fat (10E%) or a high-fat diet (45E%) for 2 weeks. During the intervention gross energy intake and energy excretion in the feces were measured. After sacrifice the small and large intestine were isolated and the small intestine was divided in three equal parts. Swiss rolls were prepared of each of the isolated segments for histological analysis and the luminal content was isolated to examine alterations in the microflora with 16S rRNA Q-PCR. Furthermore, mucosal scrapings were isolated from each segment to determine differential gene expression by microarray analysis and global DNA methylation by pyrosequencing.ResultsDigestible energy intake was similar between the two age groups on both the control and the high-fat diet. Microarray analysis on RNA from intestinal scrapings showed no marked changes in expression of genes involved in metabolic processes. Decreased expression of Cubilin was observed in the intestine of 21-month-old mice, which might contribute to aging-induced vitamin B12 deficiency. Furthermore, microarray data analysis revealed enhanced expression of a large number of genes involved in immune response and inflammation in the colon, but not in the small intestine of the 21-month-old mice. Aging-induced global hypomethylation was observed in the colon and the distal part of the small intestine, but not in the first two sections of the small intestine.ConclusionIn 21-month old mice the most pronounced effects of aging were observed in the colon, whereas very few changes were observed in the small intestine.

High-frequency electromagnetic non-destructive evaluation for high spatial resolution, using metamaterials

This study presents a new high-frequency electromagnetic method for a non-destructive evaluation of metallic strip gratings from printed circuit boards and of some carbon-fibre-reinforced plastic composites, allowing the detection of small defects. The electromagnetic transducer is based on a metamaterial lens realized with two conical Swiss rolls, that allows the transmission and intensification of purely evanescent modes generated in the slits of metallic strip gratings and in the dielectric that insulate the carbon fibres between them. The method and the transducer used allow the localization of metallic strip interruptions whose widths are greater than 0.2 mm, the non-alignment of carbon fibres, the breaking of carbon fibres, the lack of resin or delaminations due to impact at low energies, with spatial resolution being greater than 0.1 mm.

Electromagnetic imaging using evanescent waves

Metallic strip gratings have a range of applications, from printed circuits boards to filters in microwave domains. These applications impose a rigorous and rapid quality control. This paper proposes the obtaining of electromagnetic images of metallic strip gratings using evanescent waves that are formed in slits. For their detection, two procedures can be use, namely, the diffraction of evanescent waves on circular apertures and respectively, the propagation through metamaterials, conical Swiss rolls type. In this case, the spatial resolution is better than λ/1000. The use of metamaterial, conical Swiss rolls type, allows the obtaining of a resolution in the range of λ/2000, the electromagnetic image being improved.

Swiss roll ensemble homogenization by full‐wave simulations

AbstractThis paper investigates a magnetic metamaterial, built from so‐called Swiss rolls, by means of full‐wave simulations.After determining the resonance frequencies of a single Swiss roll, the macroscopic material parameters of an ensemble of Swiss rolls are determined byS‐parameter retrieval, using a bianisotropic model, that does not assume reciprocity a priori. As a result, the macroscopic permeability, permittivity, and magnetoelectric coupling coefficients are obtained as a function of frequency. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:2268–2274, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26257

Electromagnetic non-destructive evaluation using metamaterials

This paper proposes the study and implementation of metamaterials in electromagnetic non-destructive examination; these materials can serve as electromagnetic flux concentrators in the radio frequency range. Thus, the use of new types of metamaterials, namely conical Swiss roll, is proposed. Here, we present a method of extracting the necessary parameters (effective magnetic permeability and the frequency) from the data obtained by measuring network parameters. Due to the fact that conical Swiss rolls can serve as radio frequency flux concentrators, they can be used in the fabrication of electromagnetic lenses, being designed on the basis of Fourier optic principles. As a direct application, carbon fibre reinforced plastic (CFRP) plates with and without delaminations, created by impacts with low energy, were examined by means of electromagnetic transducers with a metamaterial lens. The characteristics of a carbon fibre woven structure become visible and the delaminations are clearly emphasised.

Targeted Ablation of Glucose-dependent Insulinotropic Polypeptide-producing Cells in Transgenic Mice Reduces Obesity and Insulin Resistance Induced by a High Fat Diet

The K cell is a specific sub-type of enteroendocrine cell located in the proximal small intestine that produces glucose-dependent insulinotropic polypeptide (GIP), xenin, and potentially other unknown hormones. Because GIP promotes weight gain and insulin resistance, reducing hormone release from K cells could lead to weight loss and increased insulin sensitivity. However, the consequences of coordinately reducing circulating levels of all K cell-derived hormones are unknown. To reduce the number of functioning K cells, regulatory elements from the rat GIP promoter/gene were used to express an attenuated diphtheria toxin A chain in transgenic mice. K cell number, GIP transcripts, and plasma GIP levels were profoundly reduced in the GIP/DT transgenic mice. Other enteroendocrine cell types were not ablated. Food intake, body weight, and blood glucose levels in response to insulin or intraperitoneal glucose were similar in control and GIP/DT mice fed standard chow. In contrast to single or double incretin receptor knock-out mice, the incretin response was absent in GIP/DT animals suggesting K cells produce GIP plus an additional incretin hormone. Following high fat feeding for 21-35 weeks, the incretin response was partially restored in GIP/DT mice. Transgenic versus wild-type mice demonstrated significantly reduced body weight (25%), plasma leptin levels (77%), and daily food intake (16%) plus enhanced energy expenditure (10%) and insulin sensitivity. Regardless of diet, long term glucose homeostasis was not grossly perturbed in the transgenic animals. In conclusion, studies using GIP/DT mice demonstrate an important role for K cells in the regulation of body weight and insulin sensitivity.