Hanni Siegel

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Results from previous studies had suggested that Bacteroides thetaiotaomicron utilizes starch by binding the polysaccharide to the bacterial surface and subsequently degrading the polymer by using cell-associated enzymes. Most of the starch-degrading activity was localized to the periplasm, but a portion appeared to be membrane associated. This raised the(More)
A chemically heterogeneous group of compounds, the Ca++ channel antagonists, which includes verapamil, diltiazem and nifedipine inhibits excitation-contraction coupling in smooth and cardiac muscle by blocking Ca+ entry at a specific class of Ca++ channels. The binding of the nifedipine analog, [3H]nitrendipine, to a microsomal fraction from guinea-pig(More)
BACKGROUND Alloreactive T cells and anti-human leukocyte antigen antibodies mediate transplant injury. Environmental exposures, including vaccinations, may activate the alloimmune repertoire leading to accelerated allograft injury. To test whether vaccination impacts human alloimmunity, we analyzed humoral and cellular immune reactivity in subjects(More)
Induction therapy is used in kidney transplantation to inhibit the activation of donor-reactive T cells which are detrimental to transplant outcomes. The choice of induction therapy is decided based on perceived immunological risk rather than by direct measurement of donor T-cell reactivity. We hypothesized that immune cellular alloreactivity(More)
The crystal structure of the His-175-->Gly (H175G) mutant of cytochrome-c peroxidase (EC 1.11.1.5), missing its only heme ligand, reveals that the histidine is replaced by solvent to give a bisaquo heme protein. This protein retains some residual activity, which can be stimulated or inhibited by addition of exogenous ligands. Structural analysis confirms(More)
On the basis of the experiments described here, we suggest that the mechanism of action of SRS in guinea pig ileal longitudinal muscle is very similar to that used by other agonists in this preparation, namely interactions at a specific receptor to activate Ca++ channels leading to Ca++ influx and mechanical response. SRS responses differ in 1 important(More)