RESUMO
Produce prescription projects are becoming increasingly common. This study explores perspectives and experiences of a sample of health care providers throughout the United States participating in implementing produce prescription projects with funding from the United States Department of Agriculture. Surveys (N = 34) were administered to collect demographic and descriptive data. Subsequently, individual key-informant interviews with participating health care providers (N = 16) were conducted via videoconference. Participants in this study included physicians and clinical staff (e.g., nursing, nutrition, social work) who work at health care organizations that facilitate a produce prescription project. Interview transcripts were coded using thematic qualitative analysis methods. Four cross-cutting key themes emerged. First, interviewees shared operational challenges, including lack of time/staff, difficulty with provider/patient engagement (some related to COVID-19), steep "trial and error" learning curve, and formidable barriers related to data sharing and research-related requirements (e.g., Institutional Review Board approvals). Second, interviewees elucidated their solutions, lessons learned, and emerging best practices as a response to challenges (e.g., importance of having a full-time paid staff member to manage PPR within clinic). Third, interviewees expressed satisfaction with produce prescription projects, particularly related to positive patient experiences (e.g., improved clinical outcomes and improved food security). Fourth, interviewees also shared appreciation for rigorous program evaluation to establish sustained funding and advance policies. However, they contextualized this appreciation within challenges outlined regarding collecting and sharing patient-related data outcomes. Findings provide emergent best practices and inform additional resources that are needed to sustainably implement and rigorously evaluate produce prescription projects.
RESUMO
Membrane transporters, in addition to their major role as specific carriers for ions and small molecules, can also behave as water channels. However, neither the location of the water pathway in the protein nor their functional importance is known. Here, we map the pathway for water and urea through the intestinal sodium/glucose cotransporter SGLT1. Molecular dynamics simulations using the atomic structure of the bacterial transporter vSGLT suggest that water permeates the same path as Na+ and sugar. On a structural model of SGLT1, based on the homology structure of vSGLT, we identified and mutated residues lining the sugar transport pathway to cysteine. The mutants were expressed in Xenopus oocytes, and the unitary water and urea permeabilities were determined before and after modifying the cysteine side chain with reversible methanethiosulfonate reagents. The results demonstrate that water and urea follow the sugar transport pathway through SGLT1. The changes in permeability, increases or decreases, with side-chain modifications depend on the location of the mutation in the region of external or internal gates, or the sugar binding site. These changes in permeability are hypothesized to be due to alterations in steric hindrance to water and urea, and/or changes in protein folding caused by mismatching of side chains in the water pathway. Water permeation through SGLT1 and other transporters bears directly on the structural mechanism for the transport of polar solutes through these proteins. Finally, in vitro experiments on mouse small intestine show that SGLT1 accounts for two-thirds of the passive water flow across the gut.
