The aim of this study was to determine the prevalence of upper gastrointestinal symptoms (UGIS) in a general population and quantify the relationship of those symptoms to healthcare utilization and quality of life. In-person interviews were conducted with 2056 United States and Canadian residents selected at random. Subjects reported frequency and severity for 11 symptoms, prescription and over-the-counter medication use, primary care and specialty physician visits in prior three months, and completed the Psychological General Well-Being Scale. For analyses, subjects were classified into four mutually exclusive symptom groups: gastroesophageal reflux disease (GERD) -like, GERD plus motility-like (GERD+), ulcerlike, and motility-like. Of the total sample, 51.4% reported the occurrence of at least one UGIS in the prior three months. Subjects in the GERD+ and ulcer groups used more prescription medications and were more likely to see a physician about the symptoms (P<0.001). Subjects with symptoms demonstrated poorer quality of life compared to subjects with no symptoms. The prevalence of UGIS in the general population is high and symptoms are associated with significant health-care utilization and poorer quality of life.

The complex interactions of glomerular and tubular epithelial cells with the basal laminae play a critical role in renal function. Disruption of these interactions has been widely implicated in glomerular diseases and acute renal failure. MDC are a large family of membrane-bound proteins containing metalloprotease, disintegrin (integrin interaction sites), and cysteine-rich domains. Little information is available concerning the presence of MDC in the kidney or their role in renal pathophysiology. Using degenerate PCR primers for the conserved metalloprotease and disintegrin domains of this protein family, cDNA templates from tubules, whole glomeruli, and glomerular epithelial cells (GEC) yielded a single, 195-bp product, which on sequence analysis corresponded to a region in the disintegrin domain of MDC9. Northern analysis of poly(A)+ RNA from tubules, whole glomeruli, and GEC revealed a 3.9-kb transcript, identical to that of mouse MDC9. Using antibodies generated against a 21-amino acid peptide present in the metalloprotease domain of MDC9, Western analysis of concanavalin A-enriched glomerular microsomal extracts demonstrated both processed (76 kD) and unprocessed (116 kD) forms of MDC9, which upon reduction changed to the corresponding 84- and 124-kD forms. Histochemical studies revealed a basolateral localization of intrinsic MDC9 protein in renal cortical tubule cells and glomerular visceral epithelial cells, which colocalized with the beta1 integrin chain. Expression of green fluorescence protein MDC9 chimeric constructs in GEC or polarized Madin-Darby canine kidney epithelial cells revealed a similar punctate basolateral surface localization. Transient overexpression of the soluble disintegrin domain-green fluorescence protein chimera in GEC led to dramatic changes in cellular morphology with rounding and detachment from cell monolayers. These studies document the presence of MDC9 in renal epithelial cells and suggest an important role for MDC9 in renal epithelial cellular interactions with the basal lamina and adjoining cells.