Does the haematopoietic GTPase RhoH modulate IL3 signalling through regulation of STAT activity and IL3 receptor expression?
We propose that RhoH functions as a negative regulator for IL3-induced signals through modulation of the JAK-STAT pathway. High levels of RhoH allow the IL3-dependent activation of STAT1 causing decreased proliferation through upregulation of p21Cip1 and p27Kip1. Low RhoH levels on the other hand led to an upregulation of IL3-dependent cell growth, STAT5 activity and an increase of CD123 surface expression, linking RhoH to a CD123/STAT5 phenotype that has been described in AML patients.
There is no evidence in this series of 161 hips that a matt surface finish was associated with either the premature loosening or the marked progressive osteolysis pattern of the type that has been described with the Iowa stem. The evidence in our report does not support the hypothesis that a bead-blasted surface finish in the 2 designs studied here (CAD and HD-2) lead to a high incidence of early loosening and marked progressive lysis. In general, these stems have functioned well in the long term, both clinically and radiologically. This data raises the question that other factors, such as the design, the offset, the high placement of the medial curvature of the stem, and the large body weight in the patients in the Iowa series may have contributed to the early failure of fixation of those hips in that series in conjunction with, or independent of the surface finish of that design of stem.