Helicobacter pylori (Hp) infection triggers a chronic influx of polymorphonuclear leukocyte neutrophils (PMNs) into the gastric mucosa. Although Hp reside in a neutrophil-rich environment, how these ...organisms evade phagocytic killing is largely unexplored. We now show that live Hp (strains 11637, 60190, DT61A, and 11916) are readily ingested by PMNs and induce a rapid and strong respiratory burst that is comparable to PMA. Relative to other particulate stimuli, Hp are more potent activators of PMNs than opsonized zymosan, Staphylococcus aureus, or Salmonella. Strikingly, biochemical and microscopic analyses demonstrate that Hp disrupt NADPH oxidase targeting such that superoxide anions are released into the extracellular milieu and do not accumulate inside Hp phagosomes. Specifically, nascent Hp phagosomes acquire flavocytochrome b558 but do not efficiently recruit or retain p47phox or p67phox. Superoxide release peaks at 16 min coincident with the appearance of assembled oxidase complexes in patches at the cell surface. Oxidant release is regulated by formalin-resistant and heat-sensitive bacterial surface factors distinct from urease and Hp(2-20). Following opsonization with fresh serum, Hp triggers a modest respiratory burst that is confined to the phagosome, and ingested bacteria are eliminated. We conclude that disruption of NADPH oxidase targeting allows unopsonized Hp to escape phagocytic killing, and our findings support the hypothesis that bacteria and PMNs act in concert to damage the gastric mucosa.
ABSTRACT
A reduction in stress tolerance is a hallmark of the aging process, and the lowered functional capacity observed in aged organisms is associated with an increased rate of oxidative stress ...and a greater susceptibility of aged tissues to oxidative injury. In this report, we show that chronic systemic administration of a superoxide dismutase (SOD)/catalase mimetic (EUK‐189), delivered over a 1 month period via osmotic pump, prevents heat stress‐induced liver injury by dramatically decreasing oxidative damage in aged animals. Widespread liver injury was present in old but not young vehicle‐treated rats in response to a 2 day heating protocol. However, SOD/catalase mimetic treatment markedly decreased the hyperthermia‐induced liver injury associated in old animals. The reversal of damage with EUK‐189 was associated with an improvement in intracellular redox status and a striking reduction in hepatocellular lipid peroxidation. EUK‐189 treatment also blocked the activation of activator protein‐1 (AP‐1), which is a redox‐sensitive early response transcription factor involved in the regulation of cellular stress responses. These results demonstrate that oxidative stress plays a unique role in age‐related hyperthermic injury and suggest that therapeutic strategies aimed at improving redox potential, such as chronic SOD/catalase mimetic treatment, can prevent the oxidative‐mediated damage associated with environmental stress.
Hexaploid triticale (X Triticosecale Wittmack) (2n= 6x= 42, AABBRR) and wheat (Triticum aestivum L.) (2n= 6x= 42, AABBDD) differ in their R and D-genomes. This produces differences in both agronomic ...and end-use quality characteristics. Our objective was to determine how introgressions of individual chromosomes from the D-genome of wheat affect these characteristics of a winter triticale 'Presto'. We studied the effects of 18 D-genome chromosome substitution lines, 15 sib-lines as controls, and five check cultivars at Lincoln, NE in 1996, using a randomized complete block design with two replications. The experiment was repeated at Lincoln and Mead, NE in 1997 and 1998 with 15 substitution lines that survived the first winter in Lincoln, along with their 12 control sibs and five check cultivars. Few D-genome chromosomes had positive effects. Chromosomes 2D, 4D, and 6D significantly reduced plant height when substituted for 2R, 4B, and 6R, respectively. No grain yield increases were associated with any of the D-genome chromosomes tested, but three substitutions decreased the grain yield. Depending on the allele of the hardness gene present, chromosome 5D increased or decreased kernel hardness when substituted for 5R or 5A, respectively. Introgressions of chromosomes 1D and 6D improved end-use quality characteristics of Presto. These results suggest that apart from beneficial effects of individual loci located on the D-genome chromosomes, no major benefit can be expected from D-genome chromosome substitutions.PUBLICATION ABSTRACT
We use a new method to estimate with 5% accuracy the contribution of pion and kaon in-flight-decays to the dimuon data set acquired with the CDF detector. Based on this improved estimate, we show ...that the total number and the properties of the collected dimuon events are not yet accounted for by ordinary sources of dimuons which also include the contributions, as measured in the data, of heavy flavor, Upsilon , and Drell-Yan production in addition to muons mimicked by hadronic punchthrough. The number of unaccounted events corresponds to (12.8 plus or minus 3.2)% of the $b\bar{b}$ production. We find that (23 plus or minus 6)% of the unaccounted events contain additional muon candidates. For comparison, this fraction is (6.9 plus or minus 0.4)% for events due to $b\bar{b}$ production.
A search for a narrow Higgs boson resonance in the diphoton mass spectrum is presented based on data corresponding to 7.0 fb^-1 of integrated luminosity from p-pbar collisions at sqrt(s) = 1.96 TeV ...collected by the CDF experiment. No evidence of such a resonance is observed, and upper limits are set on the cross section times branching ratio of the resonant state as a function of Higgs boson mass. The limits are interpreted in the context of the standard model and one fermiophobic benchmark model where the data exclude fermiophobic Higgs bosons with masses below 114 GeV/c^2 at a 95% Bayesian credibility level.
We use a new method to estimate with 5% accuracy the contribution of pion and kaon in-flight-decays to the dimuon data set acquired with the CDF detector. Based on this improved estimate, we show ...that the total number and the properties of the collected dimuon events are not yet accounted for by ordinary sources of dimuons which also include the contributions, as measured in the data, of heavy flavor, $\Upsilon$, and Drell-Yan production in addition to muons mimicked by hadronic punchthrough.
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