Publications by authors named "N Stephen Pollitt"

Inhibitors of angiogenic factors are known to be upregulated, and their levels increase in the maternal circulation before the onset of preeclampsia. We reproduced a previously characterized model of preeclampsia by adenoviral overexpression of the soluble vascular endothelial growth factor (VEGF) receptor sFlt-1 (also referred to as sVEGFR-1) in pregnant and nonpregnant Sprague-Dawley rats. Animals were treated with VEGF121 at 0, 100, 200, or 400 microg/kg once or twice daily (n=8 per group; 64 total) and compared with normal control animals (n=4 per group) by examination of systolic blood pressure, urinary albumin and creatinine, renal histopathology, and glomerular gene expression profiling.

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Objectives: These studies describe molecular forms of circulating B-type natriuretic peptide (BNP) as well as their biological activity.

Background: Increased circulating levels of immunoreactive BNP correlate with the severity of heart failure and are considered a sensitive biomarker. However, little is known about the molecular forms of circulating BNP and their biological activity.

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Human pro-B-type natriuretic peptide (proBNP), the precursor for B-type natriuretic peptide (BNP), was expressed in Chinese hamster ovary cells (CHO) and compared by Western blot analysis to BNP cross-reacting material immunoprecipitated from the plasma of heart failure patients. Both recombinant and native forms co-migrated as a diffuse band centered around 25 kDa and were reduced to a 12 kDa species by treatment with a mixture of O-link deglycosylation enzymes. The 108-amino acid CHO-expressed protein was examined by tryptic mapping and LC-MS and found to be an O-linked glycoprotein.

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Heparin-binding (HB) epidermal growth factor (EGF)-like growth factor (HB-EGF), a member of the EGF protein family, is a potent mitogen for fibroblasts, smooth muscle cells, and keratinocytes that was initially identified as a secreted product of macrophage-like cells. HB-EGF and EGF appear to act on target cells utilizing the same receptor, but HB-EGF is distinguishable from EGF by its strong affinity for heparin. To facilitate studies of structure-function relationships in HB-EGF, a bacterial recombinant expression system was established that produced biologically active HB-EGF with the expected disulfide bonding pattern.

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