Shannon Swink

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Purified human DNA topoisomerase I was assayed quantitatively by enzyme titrations with supercoiled pHC624 DNA in the presence of 0-2.0 microM doxorubicin. Supercoiled and relaxed DNAs were resolved by agarose gel electrophoresis in the presence of ethidium bromide, and the percentage of conversion of supercoiled DNA to relaxed DNA was quantified by(More)
The mechanisms responsible for efficient sequestration of Ag by cells of the dendritic cell (DC) lineage remain incompletely characterized. One pathway, internalization of Ag-IgG complexes via CD32 (the type II IgG FcR, Fc gamma RII) enhances Ag presentation 100-fold over noncomplexed Ag. Blood leukocytes differentially express two additional IgG FcR, Fc(More)
The effect of gender on the N1-P2 auditory complex was examined while listening and speaking with altered auditory feedback. Fifteen normal hearing adult males and 15 females participated. N1-P2 components were evoked while listening to self-produced nonaltered and frequency shifted /a/ tokens and during production of /a/ tokens during nonaltered auditory(More)
The high-affinity IgG receptor, FcgammaRI (CD64), is constitutively expressed exclusively on professional APCs. Human FcgammaRI binds monomeric IgG with high affinity and is, therefore, saturated in vivo. The binding of IgG to FcgammaRI causes receptor recycling, while Abs that cross-link FcgammaRI cause rapid down-modulation of surface FcgammaRI. Because(More)
Coagulase-negative staphylococci are the major cause of late-onset nosocomial neonatal sepsis. We prospectively examined all infants less than 6 months of age hospitalized at Children's Hospital of Philadelphia from whom at least one of two or more blood cultures grew coagulase-negative staphylococci. We considered as infections only those episodes in which(More)
Human type 1 Fc gamma receptors (Fc gamma RI) bind with high affinity (Kd = approximately 10(-9) M) Fc regions of monomeric IgG1 and IgG3. As demonstrated in this report, interaction of IgG-Fc with the ligand binding site on Fc gamma RI alters its capacity for aggregation-dependent signaling. This Fc-dependence was demonstrated in normal monocytes and(More)
The high-affinity receptor for IgG (CD64 or FcgammaRI) is constitutively expressed exclusively on professional APCs (monocytes, macrophages, and dendritic cells). When Ag is targeted specifically to FcgammaRI, Ag presentation is markedly enhanced, although the mechanism of this enhancement is unknown. In an effort to elucidate the pathways involved in(More)
This study shows that aggregation of U937 cell high affinity IgG Fc receptor (Fc gamma RI) results in the transient tyrosine phosphorylation of Fc gamma RI gamma-chain but not the phosphorylation of gamma-chains associated with nonaggregated IgA Fc receptors (Fc alpha R) on the same cells. Thus, normally, tyrosine phosphorylation of gamma-chains is limited(More)
BACKGROUND Bilingual (BL) listeners' difficulties in adverse noise conditions are exacerbated when perceiving their second language (L2) relative to their first language (L1). Perception of L2 is also significantly poorer by BL listeners compared to native monolingual (ML) listeners. PURPOSE The purpose of the study was to examine the effect of stationary(More)
PURPOSE The effects of type of stimuli (i.e., nonspeech vs. speech), speech (i.e., natural vs. synthetic), gender of speaker and listener, speaker (i.e., self vs. other), and frequency alteration in self-produced speech on the late auditory cortical evoked potential were examined. METHOD Young adult men (n = 15) and women (n = 15), all with normal(More)
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