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Tight junction disruption: Helicobacter pylori and dysregulation of the gastric mucosal barrier

World journal of Gastroenterology 2015年第40期21卷 11411-11427页

作者： Tyler j Caron Kathleen E Scott james G Fox susan j hagen Department of Surgery Beth Israel Deaconess Medical Center and Harvard Medical School Division of Comparative Medicine Massachusetts Institute of Technology

Long-term chronic infection with Helicobacter pylori(H. pylori) is a risk factor for gastric cancer development. In the multi-step process that leads to gastric cancer,tight junction dysfunction is thought to occur and serve as a risk factor by permitting the permeation of luminal contents across an otherwise tight mucosa. Mechanisms that regulate tight junction function and structure in the normal stomach,or dysfunction in the infected stomach,however,are largely unknown. Although conventional tight junction components are expressed in gastric epithelial cells,claudins regulate paracellular permeability and are likely the target of inflammation or H. pylori itself. There are 27 different claudin molecules,each with unique properties that render the mucosa an intact barrier that is permselective in a way that is consistent with cell physiology. Understanding the architecture of tight junctions in the normal stomach and then changes that occur during infection is important but challenging,because most of the reports that catalog claudin expression in gastric cancer pathogenesis are contradictory. Furthermore,the role of H. pylori virulence factors,such as cytotoxin-associated gene A and vacoulating cytotoxin,in regulating tight junction dysfunction during infection is inconsistent in different gastric cell lines and in vivo,likely because non-gastric epithelial cell cultures were initially used to unravel the details of their effects on the stomach. Hampering further study,as well,is the relative lack of cultured cell models that have tight junction claudins that are consistent with native tissues. This summary will review the current state of knowledge about gastric tight junctions,normally and in H. pylori infection,and make predictions about the consequences of claudin reorganization during H. pylori infection.

关键词： Helicobacter pylori Tight junction Claudins Parace

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Rodent management in Aotearoa New Zealand: approaches and challenges to landscape-scale control

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Integrative Zoology 2024年第1期19卷 8-26页

作者： john G.INNES Grant NORBURY Araceli SAMANIEGO susan WALKER Deborah j.WILSON Manaaki Whenua-Landcare Research HamiltonNew Zealand Manaaki Whenua-Landcare Research AlexandraNew Zealand Manaaki Whenua-Landcare Research AucklandNew Zealand Manaaki Whenua-Landcare Research DunedinNew Zealand

Aotearoa—New Zealand has only four rodent species,all *** order of arrival,they are Pacific rat Rattus exulans,brown rat ***,house mouse Mus musculus,and black rat *** management in New Zealand aims mainly to conserve indigenous biodiversity rather than to protect crops or manage diseases,as is usual *** describe four major“regimes”and one major vision for rodent control in New Zealand to meet ecological restoration *** challenges for island eradications are for large islands that are remote or populated by *** 1080 is the only large-scale(tens of thousands of hectares)option for black rat control,but its application requires adjustment to counter subsequent rapid black rat ***“ecosanctuaries”(mean 720 ha)use ground-based traps and poisons to target mainly black rats and face constant *** with mammal-resistant fences(up to 3500 ha)limit reinvasion and target more pest species and have enabled the return of previously extirpated taxa to the main *** Free 2050 aims to eradicate the rat species(but not mice)plus some other introduced mammals from New Zealand by *** vision is not attainable with current tools,but research and experimental management is exploring techniques and *** large scale(to 100000 ha)at which black rats are now targeted for control to extremely low abundance seems to be unique to New Zealand.

关键词： black rat brown rat eradication house mouse rodent control

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Pre-operative visceral adipose tissue radiodensity is a potentially novel prognostic biomarker for early endoscopic post-operative recurrence in Crohn’s disease

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World journal of Gastrointestinal Surgery 2024年第3期16卷 740-750页

作者： Phillip Gu Shishir Dube Norman Gellada So Yung Choi susan Win Yoo jin Lee Shaohong Yang Talin Haritunians Gil Y Melmed Eric A Vasiliauskas Niru Bonthala Gaurav Syal Andres j Yarur David Ziring Shervin Rabizadeh Phillip Fleshner Cindy Kallman Suzanne Devkota Stephan R Targan Dalin Li Dermot PB McGovern Department of Medicine Cedars-Sinai Medical CenterLos AngelesCA 90048United States Department of Imaging Cedars-Sinai Medical CenterLos AngelesCA 90048United States Department of Biostatistics Shared Resource Cedars-Sinai Medical CenterLos AngelesCA 90048United States Department of Internal Medicine Keimyung University School of MedicineDaegu 42601South Korea Department of Medicine University of California at Los AngelesLos AngelesCA 90095United States Department of Medicine University of California at San DiegoSan DiegoCA 92093United States Department of Pediatrics Cedars-Sinai Medical CenterLos AngelesCA 90048United States Department of Surgery Cedars-Sinai Medical CenterLos AngelesCA 90048United States

BACKGROUND Evidence suggests inflammatory mesenteric fat is involved in post-operative recurrence(POR)of Crohn’s disease(CD).However,its prognostic value is INTRODUCTION Crohn’s disease(CD)is a debilitating chronic immune-mediated inflammatory disease(IMID)of the gastrointestinal tract that is increasing in incidence and prevalence globally[1].CD patients often undergo surgery for disease-related complic-ations and/or medically refractory ***,surgery is not curative,and many patients develop post-operative recurrence(POR)of CD with a significant proportion eventually requiring additional *** advances in early detection and therapeutics,the contemporary 10-year risk of surgery has improved from 50%to 26%,but the risk of recurrent surgery has remained unchanged at 30%,suggesting a need to improve post-operative management strategies[2].Presently,there are two accepted strategies to mitigate POR,but each have potential ***,patients start early post-operative pharmacologic prophylaxis within 4-6 wk after *** strategy can potentially overtreat a subset of patient who may not develop long-term disease recurrence off ***,these patients are at risk of medication-related adverse events and the direct and indirect costs associated with therapy with little or no benefit[3].The second strategy is performing early colonoscopy within 6-12 months after surgery and escalating therapy based on FOOTNOTES Author contributions:Gu P is the guarantor of the article and was involved in concept and design,data collection,statistical analysis,drafting of manuscript,and final approval of manuscript;Dube S and Choi SY were involved in statistical analysis,drafting of the manuscript,and final approval of manuscript;Gellada N,Win S,Lee Yj and Yang S were involved in the data collection,drafting of the manuscript,and final approval of manuscript;Haritunians T and Li D were involved in data analysis and interpretation,drafting

关键词： Crohn’s disease Surgery Visceral adipose tissue Mesenteric adipose tissue Creeping fat Computed tomography

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Contribution of national bioassessment approaches for assessing ecological water security： an AUSRIVAS case study

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Frontiers of Environmental Science & Engineering 2013年第5期7卷 669-687页

作者： susan j. NICHOLS Fiona j. DYER Institute for Applied Ecology and MDBfutures CRN University of Canberra Canberra ACT 2601 Australia

River managers in Australia are managing in the face of extremes to provide security of water supply for people, production and the environment. Balancing the water requirements of people, environments and econo- mies requires that water security is viewed holistically, not just in terms of the water available for human consump- tion. Common definitions of water security focus on the needs of both humans and ecosystems for purposes such as drinking, agriculture and industrial use, and to maintain ecological values. Information about achieving water security for the environment or ecological purposes can be a challenge to interpret because the watering require- ments of key ecological processes or assets are not well understood, and the links between ecological and human values are often not obvious to water users. Yet the concepts surrounding river health are inherently linked to holistic concepts of water security. The measurement of aquatic biota provides a valuable tool for managers to understand progress toward achieving ecological water security objectives. This paper provides a comprehensive review of the reference condition approach to river health assessment, using the development of the Australian River Assessment System （AUSRIVAS） as a case study. We make the link between the biological assessment of river health and assessment of ecological water security, and suggest that such an approach provides a way of reporting that is relevant to the contribution made by ecosystems to water security. The reference condition approach, which is the condition representative of minimally disturbed sites organized by selected physical, chemical, and biological characteristics, is most important for assessing ecological water security objectives.

关键词： ecological water security biological assessment river health

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Robust Adaptive Model Tracking for Distributed Parameter Control of Linear Infinite-dimensional Systems in Hilbert Space

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IEEE/CAA journal of Automatica Sinica 2014年第3期1卷 294-301页

作者： Mark j.Balas susan A.Frost the Embry-Riddle Aeronautical University the NASA Ames Research Center

This paper is focused on adaptively controlling a linear infinite-dimensional system to track a finite-dimensional reference *** a linear continuous-time infinite-dimensional plant on a Hilbert space with disturbances of known waveform but unknown amplitude and phase,we show that there exists a stabilizing direct model reference adaptive control law with the properties of certain disturbance rejection and *** plant is described by a closed,densely defined linear operator that generates a continuous semigroup of bounded operators on the Hilbert space of *** central result will show that all errors will converge to a prescribed neighborhood of zero in an infinitedimensional Hilbert *** result will not require the use of the standard Barbalat’s lemma which requires certain signals to be uniformly *** result is used to determine conditions under which a linear infinite-dimensional system can be directly adaptively controlled to follow a reference *** particular,we examine conditions for a set of ideal trajectories to exist for the tracking *** results are applied to adaptive control of general linear diffusion systems described by self-adjoint operators with compact resolvent.

关键词： Adaptation models Adaptive control Hilbert space Learning (artificial intelligence) Robustness Trajectory adaptive control algorithm adaptive theory distributed parameter system Distributed parameter systems Hilbert space trajectory Adaptation models reference model adaptive control Robustness Computer algorithms

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TIC-Tox: A preliminary discussion on identifying the forcing agents of DBP-mediated toxicity of disinfected water

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journal of Environmental Sciences 2017年第8期29卷 208-216页

作者： Michael j.Plewa Elizabeth D.Wagner susan D.Richardson Safe Global Water Institute and the Department of Crop Sciences University of Illinois at Urbana-Champaign Department of Chemistry and Biochemistry University of South Carolina

The disinfection of drinking water is a major public health achievement; however, an unintended consequence of disinfection is the generation of disinfection by-products（DBPs）. Many of the identified DBPs exhibit in vitro and in vivo toxicity, generate a diversity of adverse biological effects, and may be hazards to the public health and the *** a few DBPs are regulated by several national and international agencies and it is not clear if these regulated DBPs are the forcing agents that drive the observed toxicity and their associated health effects. In this study, we combine analytical chemical and biological data to resolve the forcing agents associated with mammalian cell cytotoxicity of drinking water samples from three cities. These data suggest that the trihalomethanes（THMs） and haloacetic acids may be a small component of the overall cytotoxicity of the organic material isolated from disinfected drinking water. Chemical classes of nitrogen-containing DBPs, such as the haloacetonitriles and haloacetamides, appear to be the major forcing agents of toxicity in these samples. These findings may have important implications for the design of epidemiological studies that primarily rely on the levels of THMs to define DBP exposure among populations. The TIC-Tox approach constitutes a beginning step in the process of identifying the forcing agents of toxicity in disinfected water.

关键词： DBPs CHO cell cytotoxicity Toxicity Additivity

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Cell Wall Microstructure Analysis Implicates Hemicellulose Polysaccharides in Cell Adhesion in Tomato Fruit Pericarp Parenchyma

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Molecular Plant 2009年第5期2卷 910-921页

作者： jose j. Ordaz-Ortiz susan E. Marcus j. Paul Knox Centre for Plant Sciences Faculty of Biological Sciences University of Leeds Leeds LS2 9JT United Kingdom

Methods developed to isolate intact cells from both unripe and ripe tomato fruit pericarp parenchyma have allowed the cell biological analysis of polysaccharide epitopes at the surface of separated cells. The LM7 pectic homogalacturonan epitope is a marker of the junctions of adhesion planes and intercellular spaces in parenchyma systems. The LM7 epitope persistently marked the former edge of adhesion planes at the surface of cells separated from unripe and ripened tomato fruit and also from fruits with the Cnr mutation. The LM 11 xylan epitope was associated, in sections, with cell walls lining intercellular space but the epitope was not detected at the surface of isolated cells, being lost during cell isolation. The LM15 xyloglucan epitope was present at the surface of cells isolated from unripe fruit in a pattern reflecting the former edge of cell adhesion planes/intercellular space but with gaps and apparent breaks. An equivalent pattern of LM15 epitope occurrence was revealed at the surface of cells isolated by pectate lyase action but was not present in cells isolated from ripe fruit or from Cnr fruit. In contrast to wild-type cells, the LM5 galactan and LM21 mannan epitopes occurred predominantly in positions reflecting intercellular space in Cnr, suggesting a concerted alteration in cell wall microstructure in response to this mutation. Galactanase and mannanase, along with pectic homogalacturonan-degrading enzymes, were capable of releasing cells from unripe fruit parenchyma. These observations indicate that hemicellulose polymers are present in architectural contexts reflecting cell adhesion and that several cell wall polysaccharide classes are likely to contribute to cell adhesion/cell separation in tomato fruit pericarp parenchyma.

关键词： Cell walls fruit development tomato cell adhesion cell separation polysaccharide.

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Assessing the utility of dissolved organic matter photoreactivity as a predictor of in situ methylmercury concentration

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journal of Environmental Sciences 2018年第6期30卷 160-168页

作者： Sara j.Klapstein susan E.Ziegler David A.Risk Nelson j.O'Driscoll Environmental Science Program Memorial University of Newfoundland Department of Earth Sciences St. Francis Xavier University Department of Earth and Environmental Science Acadia University

Methylmercury（MeHg） bioaccumulation is a growing concern in ecosystems worldwide. The absorption of solar radiation by dissolved organic matter（DOM） and other photoreactive ligands can convert MeHg into less toxic forms of mercury through photodemethylation. In this study, spectral changes and photoreactivity of DOM were measured to assess the potential to control photoreactions and predict in situ MeHg concentration. Water samples collected from a series of lakes in southwestern Nova Scotia in june, August, and September were exposed to controlled ultraviolet-A（UV-A） radiation for up to 24 hr. Dissolved organic matter photoreactivity, measured as the loss of absorbance at 350 nm at constant UV-A irradiation, was positively dependent on the initial DOM concentration in lake waters（r^2=0.94）. This relationship was consistent over time with both DOM concentration and photoreactivity increasing from summer into fall across lakes. Lake in situ MeHg concentration was positively correlated with DOM concentration and likely catchment transport in june（r = 0.77） but not the other sampling months. Despite a consistent seasonal variation in both DOM and Fe, and their respective correlations with MeHg, no discernable seasonal trend in MeHg was observed. However, a 3-year dataset from the 6 study lakes revealed a positive correlation between DOM concentration and both Fe（r = 0.91） and MeHg concentrations（r = 0.51） suggesting a more dominant landscape mobility control on *** DOM-MeHg relationships observed in these lakes highlights the need to examine DOM photoreactivity controls on MeHg transport and availability in natural waters particularly given future climate perturbations.

关键词： Methylmercury Dissolved organic carbon Photoreactions Kejimkujik National Park Freshwater lakes

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What paintings say

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作者： hagen Rainer

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Using classification assignment rules to assess land-use change impacts on forest biodiversity at local-to-national scales

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Forest Ecosystems 2018年第2期5卷 162-176页

作者： Kathrin Affeld susan K. Wiser Ian j. Payton Miquel DeCaceres Manaaki Whenua - Landcare Research PO Box 69040 Lincoln 7640 New Zealand Lincoln University PO Box 85084 Lincoln 7647 New Zealand Forest Science Centre of Catalonia Ctra. Sant Llorenc km.2 E-25280 Solsona Spain

Background： Ecosystem representation is one key component in assessing the biodiversity impacts of land-use changes that will irrevocably alter natural ecosystems. We show how detailed vegetation plot data can be used to assess the potential impact of inundation by a proposed hydroelectricity dam in the Mokihinui gorge, New Zealand, on representation of natural forests. Specifically we ask： 1） How well are the types of forest represented Locally, regionally, and nationally; and 2） How does the number of distinct communities （i.e. beta diversity） in the target catchment compare with other catchments nationally？ Methods： For local and regional comparisons plant species composition was recorded on 45 objectively located 400 m2 vegetation plots established in each of three gorges, with one being the proposed inundation area of the Mokihinui lower gorge. The fuzzy classification framework of noise clustering was used to assign these plots to a specific alliance and association of a pre-existing national-scale classification. NationaLly, we examined the relationship between the number of alliances and associations in a catchment and either catchment size or the number of plots per catchment by fitting Generalised Additive Models. Results： The four alliances and five associations that were observed in the Mokihinui lower gorge arepresent in the region but limited locally. One association was narrowly distributed nationally, but is the mostfrequent association in the Mokihinui lower gorge; inundation may have consequences of national importance to its long-term persistence. That the Mokihinui lower gorge area had nearly twice as many plots that could not be assigned to pre- existing alliances and associations than either the Mokihinui upper or the Karamea lower gorges and proportionally more than the national dataset emphasises the compositional distinctiveness of this gorge. These outlier plots in the Mokihinui lower gorge may be unsorted assemblages of species or reflect

关键词： Beta-diversity Biodiversity conservation Environmental impacts Ecosystem representation Hydroelectricity dams Land-use change National vegetation classification Noise clustering New Zealand NVS databank Plant community composition

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