Purpose: In the United States, stillbirths (fetal deaths ≥ 20 weeks' gestation) are now more common than infant deaths. Nationally available data are limited, and little is known about women's experiences around the time of a loss. The Pregnancy Risk Assessment Monitoring System (PRAMS), a state-based survey of women with a recent live birth, could be expanded to include women who experienced a stillbirth. We aimed to determine whether women with a recent stillbirth would be amenable to a PRAMS-like survey.
Methods: Eligible women were Georgia residents aged ≥18 years with a reported stillbirth from December 1, 2012-February 28, 2013 identified through fetal death certificates. Women received a handwritten sympathy card, followed by a mailed questionnaire about their health and experiences around the time of the loss. Nonresponders received two additional mailings and up to three phone calls.
Results: During the study period, 149 eligible women had a reported stillbirth. Forty-nine (33%) women responded. Excluding women with invalid contact information (n = 26) yields an adjusted response rate of 40%. Response differed by race and/or ethnicity, but not by fetal, delivery, or other maternal characteristics.
Conclusions: Women appear willing to respond to a survey regarding a recent stillbirth. Further studies of the expansion of PRAMS to include stillbirth are warranted.
Two urea transporters, UT-A1 and UT-A3, are expressed in the kidney terminal inner medullary collecting duct (IMCD) and are important for the production of concentrated urine. UT-A1, as the largest isoform of all UT-A urea transporters, has gained much attention and been extensively studied; however, the role and the regulation of UT-A3 are less explored. In this study, we investigated UT-A3 regulation by glycosylation modification. A site-directed mutagenesis verified a single glycosylation site in UT-A3 at Asn279. Loss of the glycosylation reduced forskolin-stimulated UT-A3 cell membrane expression and urea transport activity. UT-A3 has two glycosylation forms, 45 and 65 kDa. Using sugar-specific binding lectins, the UT-A3 glycosylation profile was examined. The 45-kDa form was pulled down by lectin concanavalin A (Con A) and Galant husnivalis lectin (GNL), indicating an immature glycan with a high amount of mannose (Man), whereas the 65-kDa form is a mature glycan composed of acetylglucosamine (GlcNAc) and poly-N-acetyllactosame (poly-LacNAc) that was pulled down by wheat germ agglutinin (WGA) and tomato lectin, respectively. Interestingly, the mature form of UT-A3 glycan contains significant amounts of sialic acid. We explored the enzymes responsible for directing UT-A3 sialylation. Sialyltransferase ST6GalI, but not ST3GalIV, catabolizes UT-A3 α2,6-sialylation. Activation of protein kinase C (PKC) by PDB treatment promoted UT-A3 glycan sialylation and membrane surface expression. The PKC inhibitor chelerythrine blocks ST6GalI-induced UT-A3 sialylation. Increased sialylation by ST6GalI increased UT-A3 protein stability and urea transport activity. Collectively, our study reveals a novel mechanism of UT-A3 regulation by ST6GalI-mediated sialylation modification that may play an important role in kidney urea reabsorption and the urinary concentrating mechanism.