The threshold for frequent PED use was more than 5 visits per patient within the first 36 months of life. Further study is needed to better define this population and develop targeted interventions to ensure care provision occurs in the ideal setting.

Our findings help to characterize the variability of faculty mentoring in EM, identify opportunities for improvement, and underscore the need to learn from other successful mentoring programs. This study can serve as a basis to share mentoring practices and stimulate conversation around strategies to improve faculty mentoring in EM.

No abstract

Several factors are thought to limit the efficiency of retroviral transduction in clinical gene therapy protocols that target hematopoietic stem cells. For example, the level of expression of the amphotropic receptor Pit-2, a phosphate symporter, appears to be low in human and murine hematopoietic stem cells. We have previously demonstrated that transduction of hematopoietic cells in the presence of the fibronectin (FN) fragment CH-296 is extremely efficient (H. Hanenberg, X. L. Xiao, D. Dilloo, K. Hashino, I. Kato, and D. A. Williams, Nat. Med. 2:876–882, 1996). To examine functionally whether the retrovirus receptor is a limiting factor in transduction of hematopoietic cells, we performed competition experiments in the presence of FN CH-296 with retrovirus vectors pseudotyped with the same or a different envelope protein. We demonstrate in both human erythroleukemia (HEL) cells and primary human CD34+hematopoietic cells inhibition of efficient infection due to receptor interference when two vectors targeting the amphotropic receptor are used simultaneously. Receptor interference lasted up to 24 h. No interference was demonstrated when vectors targeting the amphotropic receptor and the gibbon ape leukemia virus (GALV) receptor Pit-1 were used concurrently. In contrast, simultaneous infection with vectors targeting both Pit-1 and Pit-2 yielded transduction efficiencies consistently higher than with either vector alone in both HEL cells and human CD34+ hematopoietic cells. These data demonstrate that the use of FN CH-296 leads to amphotropic receptor saturation in these cells. Simultaneous infection with vectors targeting both amphotropic and GALV receptors may prove to be of additional benefit in the design of gene therapy protocols.

In efforts to identify children at risk for maltreatment, objective assessments such as PED utilization are potential markers to utilize to aid in recognition. Unfortunately, there are many risk factors for increased PED utilization that act as confounders for this marker. Future work is necessary to identify children at risk for maltreatment in the ED.