110,202 research outputs found
Parthenolide attenuates LPS-induced activation of NF-κB in a time-dependent manner in rat myocardium.
Parthenolide (PTN), a selective nuclear factor kappa B (NF-κB) inhibitor, has been used extensively to inhibit NF-κB activation. The duration of the inhibitory effect of PTN on NF-κB in vivo remains unclear. This study was to determine whether a lipopolysaccharide (LPS) challenge 6, 12 and 24 h after the administration of PTN could activate NF-κB. Rats were devided into five groups. The rats in the PTN, PTN+LPS and DMSO groups were injected intraperitoneally with PTN or DMSO. After 6, 12 or 24 h, LPS was administered in LPS and PTN+LPS groups. The expressions of NF-κB p50, IκBα and p-IκBα were inhibited in both PTN and PTN+LPS group at end of 6 and 12 h and no effects at 24 h. In summary, myocardial NF-κB expression occurs 1 h after the administration of LPS. PTN blocks this effect given at 6 h and no inhibitory effect 24 h after administration in vivo
A proof of Mader's conjecture on large clique subdivisions in -free graphs
Given any integers , we show there exists some such
that any -free graph with average degree contains a subdivision of
a clique with at least vertices. In particular,
when this resolves in a strong sense the conjecture of Mader in 1999 that
every -free graph has a subdivision of a clique with order linear in the
average degree of the original graph. In general, the widely conjectured
asymptotic behaviour of the extremal density of -free graphs suggests
our result is tight up to the constant .Comment: 25 pages, 1 figur
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