Measurement of the

The cross section of the ^{13}C(α,n)^{16}O reaction is needed for nuclear astrophysics and applications to a precision of 10% or better, yet inconsistencies among 50 years of experimental studies currently lead to an uncertainty of ≈15%. Using a state-of-the-art neutron detection array, we have performed a high resolution differential cross section study covering a broad energy range. These measurements result in a dramatic improvement in the extrapolation of the cross section to stellar energies potentially reducing the uncertainty to ≈5% and resolving long standing discrepancies in higher energy data.

Autoimmune pancreatitis results from loss of TGFbeta signalling in S100A4-positive dendritic cells.

BACKGROUND AND AIMS: Autoimmune pancreatitis (AIP) is a poorly understood human disease affecting the exocrine pancreas. The goal of the present study was to elucidate the pathogenic mechanisms underlying pancreatic autoimmunity in a murine disease model. METHODS: A transgenic mouse with an S100A4/fibroblast-specific protein 1 (FSP1) Cre-mediated conditional knockout of the transforming growth factor beta (TGFbeta) type II receptor, termed Tgfbr2(fspKO), was used to determine the direct role of TGFbeta in S100A4(+) cells. Immunohistochemical studies suggested that Tgfbr2(fspKO) mice develop mouse AIP (mAIP) characterised by interlobular ductal inflammatory infiltrates and pancreatic autoantibody production. Fluorescence-activated cell sorting (FACS)-isolated dendritic cells (DCs) from diseased pancreata were verified to have S100A4-Cre-mediated DNA recombination. RESULTS: The Tgfbr2(fspKO) mice spontaneously developed mAIP by 6 weeks of age. DCs were confirmed to express S100A4, a previously reported protein expressed by fibroblasts. Adoptive transfer of bone marrow-derived DCs from Tgfbr2(fspKO) mice into 2-week-old syngenic wild-type C57BL/6 mice resulted in reproduction of pancreatitis within 6 weeks. Similar adoptive transfer of wild-type DCs had no effect on pancreas pathology of the host mice. The inability to induce pancreatitis by adoptive transfer of Tgfbr2(fspKO) DCs in adult mice suggested a developmental event in mAIP pathogenesis. Tgfbr2(fspKO) DCs undergo elevated maturation in response to antigen and increased activation of naïve CD4-positive T cells. CONCLUSION: The development of mAIP in the Tgfbr2(fspKO) mouse model illustrates the role of TGFbeta in maintaining myeloid DC immune tolerance. The loss of immune tolerance in myeloid S100A4(+) DCs can mediate mAIP and may explain some aspects of AIP disease pathogenesis.

Beta2-adrenergic receptor stimulation inhibits nitric oxide generation by Mycobacterium avium infected macrophages.

Catecholamine regulation of nitric oxide (NO) production by IFNgamma-primed macrophages infected with Mycobacterium avium was investigated. Epinephrine treatment of IFNgamma-primed macrophages at the time of M. avium infection inhibited the anti-mycobacterial activity of the cells. The anti-mycobacterial activity of macrophages correlated with NO production. Using specific adrenergic receptor agonists, the abrogation of mycobacterial killing and decreased NO production by catecholamines was shown to be mediated via the beta2-adrenergic receptor. Elevation of intracellular cAMP levels mimicked the catecholamine-mediated inhibition of NO in both M. avium infected and LPS stimulated macrophages. Specific inhibitors of both adenylate cyclase and protein kinase A prevented the beta2-adrenoceptor-mediated inhibition of nitric oxide production. Beta2-adrenoreceptor stimulation at the time of M. avium infection of IFNgamma-primed macrophages also inhibited expression of iNOS mRNA. These observations show that catecholamine hormones can affect the outcome of macrophage-pathogen interactions and suggest that one result of sympathetic nervous system activation is the suppression of the capacity of macrophages to produce anti-microbial effector molecules.

Synergistic interaction of catecholamine hormones and Mycobacterium avium results in the induction of interleukin-10 mRNA expression by murine peritoneal macrophages.

The results of this investigation provides evidence that catecholamine hormones interact with macrophages that are infected with Mycobacterium avium resulting in the induction of IL-10 mRNA and protein. The effect of catecholamine hormones was prevented by treating the cells with the beta-adrenergic receptor antagonist propranolol but not by alpha-adrenergic antagonist phentolamine. The effect of catecholamine stimulation was mimicked by the addition of beta-2 adrenergic agonists and by the addition of cAMP to the infected macrophage cultures. These observations suggest that sympathetic nervous system activation together with microbial infection results in a synergistic interaction that could result in the control of inflammatory processes.