Histiocytoses are a group of rare disorders characterized by a proliferation of monocytes/macrophages and dendritic cells. We present a case of a 3‐year‐old girl with a diffuse papular eruption without systemic symptoms demonstrating a proliferation of strongly CD1a+ histiocytes, but negative for S‐100 and langerin on histopathology. Systemic work‐up including bone marrow biopsy was unremarkable, and the patient received a diagnosis of CD1a+ S− 100‐indeterminate cell histiocytosis.
The ability to examine the spatial and temporal localization of proteins in living cells through the use of fluorescent tags is a powerful tool for investigating the organization and dynamics of many cellular processes. We are applying this technology to studies on the NADPH oxidase expressed in neutrophils and monocyte/macrophages. This enzyme catalyzes the first step leading to the generation of potent microbicidal oxidants, which are critical for the killing of many bacterial and fungal pathogens. The importance of the NADPH oxidase to host defense is attested to by the impact of genetic defects in this enzyme, which result in Chronic Granulomatous Disease. In order to better understand the assembly and molecular regulation of this multi-subunit enzyme during phagocytosis, we are analyzing and testing fluorescently tagged derivatives of the NADPH oxidase subunits. The assembly of cytosolic factors p47 phox and p67 phox with flavocytochrome b 558 (gp91 phox and p22 phox ) at the membrane is a crucial step in enzyme activation. The p47 phox and p67 phox subunits are linked via a high-affinity, tail-to-tail interaction involving a proline-rich region (PRR) in an SH3 domain, respectively, in their C-termini. This interaction is critical for p47 phox dependent p67 phox membrane translocation. To investigate molecular rearrangements of p47 phox and p67 phox during oxidase activation, a fragment derived from the p47 phox PRR and tagged with YFP (p47/YFP) was generated and shown to bind to recombinant p67 phox in vitro. When expressed in PLB-985 granulocytes, this fragment was recruited to phagosomes. This suggests that the C-terminal SH3 domain of p67 phox becomes accessible following oxidase assembly. Additional studies are examining the role of p40 phox , an additional regulatory subunit of the NADPH oxidase that has a phosphoinositide binding site critical for oxidase activity on phagosomes (Suh, et al, J Exp Med, In Press). Whether p40 phox also promotes recruitment of p67 phox to the membrane or acts as an allosteric regulator is being examined in similar studies using fluorescently tagged derivatives while imaging living granulocytes undergoing phagocytosis. TRENDS IN SINUS OF VALSALVA DILATION AFTER THE ROSS PROCE-DURE.E. C. Kirkpatrick, E. S. Ebenroth, R. A. Hurwitz, Indianapolis, Indiana. Riley Children's Hospital, Department of Pediatric Cardiology Purpose: Since its original description in 1967 by Dr. Ross, the use of a pulmonary valve autograft for aortic valve replacement is becoming more prevalent. We analyzed pre and post operative data of pts who underwent the Ross procedure at Riley Children's Hospital in Indianapolis Indiana in order to follow trends of survival, reoperation, outflow valve integrity and aortic root dilation. This is a sub-analysis of nine patients who had multiple serial echocardiograms available for review. Methods: Clinical and echocardiographic data were reviewed on 81 consecutive children (nϭ66) and adults (nϭ14) that had a Ross procedure between 1993 and 2005. Median age at t...
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