The present study was undertaken to determine if cultures of human proximal tubule cells would retain in vivo properties inherent to this segment in the intact nephron. Ussing chamber studies demonstrated that these cultured cells generated transepithelial potential differences of approximately -2.0 mV and resistances of 0.310 K omega.cm2, supporting the concept that the proximal tubule is a "leaky" epithelium. The electrical properties did not change when the cells were exposed to amiloride (10(-4) M), but did respond to acetazolamide (10(-4) M), consistent with responses known to occur in proximal tubules. Ultrastructural analysis of these cells demonstrated features indicative of proximal tubule cells. When grown on permeable supports, where apical and basolateral growth medium compartments were maintained separate from each other, the cells were noted to undergo increased differentiation with morphological evidence of cell polarity. Freeze fracture analysis demonstrated well-formed tight junction strands and segregation of unique numbers of intramembranous particles in apical, lateral, and basal membranes. The replicas also demonstrated the presence of aggregates though to represent gap junctions, structures which occur exclusively in the proximal segment of the human nephron. These observations provide evidence that this human cell culture model originates from the human proximal tubule and retains, in culture, many of the properties associated with proximal tubule cell function and structure in vivo.

The Patient Protection and Affordable Care Act provided community health workers (CHWs) with new opportunities, and current efforts develop evidence-based guidelines for CHW integration into clinical teams. This qualitative study documents CHW roles and activities in 3 federally qualified health care centers in southern Arizona. Community health worker clinical roles, activities, and integration varied by health center and were in flux. Integration included complementary roles, scheduled and everyday communications with team members, and documentation in the electronic health records. These findings contribute to evidence-based guidelines for CHW integration into clinical teams that are critical to maximizing CHW contributions to patient health improvements.