A challenge to lepton universality in B-meson decays.

One of the key assumptions of the standard model of particle physics is that the interactions of the charged leptons, namely electrons, muons and taus, differ only because of their different masses. Whereas precision tests comparing processes involving electrons and muons have not revealed any definite violation of this assumption, recent studies of B-meson decays involving the higher-mass tau lepton have resulted in observations that challenge lepton universality at the level of four standard deviations. A confirmation of these results would point to new particles or interactions, and could have profound implications for our understanding of particle physics.

Temporal small-vessel inflammation in patients with giant cell arteritis: clinical course and preliminary immunohistopathologic characterization.

Objective: To investigate the occurrence, clinical correlates, and immunohistochemical phenotype of temporal small-vessel inflammation (TSVI) in temporal artery biopsies from patients presenting with clinical features of giant cell arteritis (GCA).

Methods: We retrospectively reviewed 41 temporal artery biopsy specimens for the presence of inflammatory infiltrates in small vessels external to the temporal artery adventitia (TSVI); 33 had sufficient clinical and pathological data for detailed analysis. Clinical and laboratory features at presentation and corticosteroid treatment patterns of patients with isolated TSVI were compared to those of patients with positive and negative biopsies.

IGM is required for efficient complement mediated phagocytosis of apoptotic cells in vivo.

A variety of complement components have been detected on apoptotic cells and proposed to facilitate recognition and/or ingestion by phagocytes. The triggers for complement activation remain uncertain. To determine the role of IgM in classical pathway activation and clearance of apoptotic cells in vitro and in vivo, we quantified these parameters in mice deficient in serum IgM (sIgM).

The role of IgM antibodies in the recognition and clearance of apoptotic cells.

Apoptotic cells not only translocate phosphatidylserine to the outside of the membrane, they activate phospholipases that remodel their membranes resulting in the exposure and diffusion of altered phospholipids. These altered phospholipids include lysophosphotidylcholine (LPC) that is a ligand for CRP and is also antigenic for natural IgM antibodies. Furthermore, soluble LPC acts as a "find me" signal to attract phagocytes to migrate toward apoptotic cells.

Dark matter particle production in b-->s transitions with missing energy.

Dedicated underground experiments searching for dark matter have little sensitivity to GeV and sub-GeV masses of dark matter particles. We show that the decay of B mesons to K(K(*)) and missing energy in the final state can be an efficient probe of dark matter models in this mass range. We analyze the minimal scalar dark matter model to show that the width of the decay mode with two dark matter scalars B-->KSS may exceed the decay width in the standard model channel, B-->Knunu , by up to 2 orders of magnitude.

Aberrant extracellular and dendritic cell (DC) surface expression of heat shock protein (hsp)70 in the rheumatoid joint: possible mechanisms of hsp/DC-mediated cross-priming.

We describe, in rheumatoid arthritis (RA), abnormalities in the expression and distribution of heat shock protein (hsp) and dendritic cells (DCs) that are conducive to cross-priming and DC cross-talk. As detected by ELISA, inducible (i)hsp70 was dramatically increased in RA synovial fluid (RASF) vs normal human and RA sera and osteoarthritis and gout synovial fluid. Immunoblot analysis of fresh RASF cells revealed marked increases in ihsp70 and activation of its transcription factor heat shock factor-1, compared with fresh normal peripheral blood cells.