Natural History of Pressure Injury Among Ethnically/Racially Diverse Nursing Home Residents: The Pressure Ulcer Detection Study.

The current observational study provides descriptive data on 270 pressure injuries (PrIs) among 142 racially/ethnically diverse nursing home (NH) residents over 16 weeks. Weekly assessments were conducted with the Bates-Jensen Wound Assessment Tool. NH data were obtained from public government websites. NH, resident, and PrI characteristics across race/ethnicity groups were compared using analysis of variance and chi-square. Participants were 62% female and 89% functionally dependent. More Black and Asian individuals had peripheral vascular disease. More Black individuals had persistent trunk and Stage 4 PrIs. Black and Hispanic individuals had normal skin color surrounding PrIs. More Asian individuals had PrIs surrounded by purple/red discolored skin. More Black individuals' heel PrIs were unstageable, necrotic, and showed no granulation. Black and Hispanic individuals exhibited more deep tissue injury. No NH or prevention differences existed. Health disparities found validate administrative data results. Differences in PrI characteristics should be further examined among diverse NH residents. [Journal of Gerontological Nursing, 47(3), 37-46.].

YRRL motifs in the cytoplasmic domain of the thrombopoietin receptor regulate receptor internalization and degradation.

Thrombopoietin (Tpo), acting through the c-Mpl receptor, promotes the survival and proliferation of hematopoietic stem and progenitor cells and drives megakaryocyte differentiation. The proproliferation and survival signals activated by Tpo must therefore be tightly regulated to prevent uncontrolled cell growth. In this work, we determined the mechanisms that control Tpo-stimulated c-Mpl internalization and defined the processes leading to its degradation. Stimulation of BaF-Mpl cells with Tpo leads to rapid, clathrin-dependent endocytosis of the receptor. Using small interfering RNA (siRNA), we found that inhibition of adaptor protein 2 (AP2), which mediates endocytosis of transmembrane proteins, strongly attenuates Tpo-stimulated c-Mpl internalization. AP2 interacts with YXXPhi motifs and we identified 2 such motifs in c-Mpl (Y(8)RRL and Y(78)RRL) and investigated Tpo-stimulated internalization of receptors bearing point mutations at these sites. After Tpo stimulation, internalization was greatly reduced in c-Mpl Y(78)F and c-Mpl Y(8+78)F, and these cell lines also exhibited increased proliferation and increased strength and duration of Jak2, STAT5, AKT, and ERK1/2 activation in response to Tpo. We also found that the Y(8)RRL motif regulates Tpo-stimulated lysosomal degradation of c-Mpl. Our data establishes that c-Mpl cytoplasmic YRRL motifs are responsible for both Tpo-mediated internalization via interactions with AP2 and lysosomal targeting after endocytosis.