Cardioprotective effect of ornitho-kinin in an anesthetized, open-chest chicken model of acute coronary occlusion

The generation of bradykinin (BK; Arg-Pro-Pro-Gly-Phe-Ser-Pro-Phe-Arg) in blood and kallidin (Lys-BK) in tissues by the action of the kallikrein-kinin system has received little attention in non-mammalian vertebrates. In mammals, kallidin can be generated by the coronary endothelium and myocytes in response to ischemia, mediating cardioprotective events. The plasma of birds lacks two key components of the kallikrein-kinin system: the low molecular weight kininogen and a prekallikrein activator analogous to mammalian factor XII, but treatment with bovine plasma kallikrein generates ornitho-kinin [Thr6,Leu8]-BK. The possible cardioprotective effect of ornitho-kinin infusion was investigated in an anesthetized, open-chest chicken model of acute coronary occlusion. A branch of the left main coronary artery was reversibly ligated to produce ischemia followed by reperfusion, after which the degree of myocardial necrosis (infarct size as a percent of area at risk) was assessed by tetrazolium staining. The iv injection of a low dose of ornitho-kinin (4 µg/kg) reduced mean arterial pressure from 88 ± 12 to 42 ± 7 mmHg and increased heart rate from 335 ± 38 to 402 ± 45 bpm (N = 5). The size of the infarct was reduced by pretreatment with ornitho-kinin (500 µg/kg infused over a period of 5 min) from 35 ± 3 to 10 ± 2% of the area at risk. These results suggest that the physiological role of the kallikrein-kinin system is preserved in this animal model in spite of the absence of two key components, i.e., low molecular weight kininogen and factor XII

Limits on anomalous triple gauge couplings in pp̄ collisions at s=1.96TeV

We present a search for anomalous triple gauge couplings (ATGC) in WW and WZ boson production. The boson pairs are produced in pp̄ collisions at s=1.96TeV, and the data sample corresponds to 350pb-1 of integrated luminosity collected with the CDF II detector at the Fermilab Tevatron. In this search one W decays to leptons, and the other boson (W or Z) decays hadronically. Combining with a previously published CDF measurement of Wγ boson production yields ATGC limits of -0.18<λ<0.17 and -0.46<Δκ<0.39 at the 95% confidence level, using a cutoff scale Λ=1.5TeV. © 2007 The American Physical Society

Search for heavy long-lived particles that decay to photons at CDF II

We present the first search for heavy, long-lived particles that decay to photons at a hadron collider. We use a sample of Î+jet+missing transverse energy events in pp collisions at s=1.96 TeV taken with the CDF II detector. Candidate events are selected based on the arrival time of the photon at the detector. Using an integrated luminosity of 570pb-1 of collision data, we observe 2 events, consistent with the background estimate of 1.3 0.7 events. While our search strategy does not rely on model-specific dynamics, we set cross section limits in a supersymmetric model with I E 10 GE and place the world-best 95% C.L. lower limit on the χ˜10 mass of 101 GeV/c2 at Ï.,χ˜10=5ns. © 2007 The American Physical Society

Cross section measurements of high-pT dilepton final-state processes using a global fitting method

We present a new method for studying high-pT dilepton events (e±e, μ±μ, e±μ) and simultaneously extracting the production cross sections of pp̄→tt̄, pp̄→W+W-, and pp̄→Z0→τ+τ- at a center-of-mass energy of s=1.96TeV. We perform a likelihood fit to the dilepton data in a parameter space defined by the missing transverse energy and the number of jets in the event. Our results, which use 360pb-1 of data recorded with the CDF II detector at the Fermilab Tevatron Collider, are σ(tt̄)=8.5-2.2+2.7pb, σ(W+W-)=16.3-4. 4+5.2pb, and σ(Z0→τ+τ-)=291-46+50pb. © 2008 The American Physical Society