American journal of hypertension
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Pheochromocytoma, a rare and usually curable cause of hypertension, is characterized by symptoms and signs related to increased catecholamine secretion. Pregnancy can elicit clinical manifestations of otherwise unrecognized pheochromocytoma. ⋯ Although rare, pheochromocytoma can cause severe peripartum hypertension. Screening for pheochromocytoma, ideally with plasma-free metanephrines, should be considered in cases of peripartum hypertension.
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Activation of RhoA/Rho kinase (ROK) pathway by angiotensin II (Ang II) is involved in the pathophysiology of hypertension and remodeling. In Bartter's and Gitelman's syndrome (BS/GS), the short-term and long-term signaling of Ang II are blunted. The BS/GS have also reduced expression and response on Ang II challenge of ROK, which indicate downregulation of RhoA/ROK pathway. As causes for RhoA/ROK downregulation in BS/GS, we hypothesized an alteration at the level of the upstream regulators of RhoA such as reduced expression of Rho guanine nucleotide exchange factor (RhoGEF), which links activation of G protein-coupled receptors to RhoA/ROK signaling or increased guanine nucleotide dissociation inhibitor (RhoGDI), which inhibits dissociation of GDP from GDI maintaining RhoA in an inactive state. ⋯ Reduced p115RhoGEF may explain the downregulation of RhoA/ROK pathway in BS/GS. This is the first report of upstream regulators of RhoA level in BS/GS, a human clinical condition characterized by reduced vascular tone regulation. Because BS/GS represent the mirror image of derangements involved in hypertension, the reduced RhoGEF expression in BS/GS underlines a major impact of RhoA/ROK pathway on blood pressure regulation and confirms BS/GS as a good human model for exploring mechanisms involved in the pathophysiology of hypertension and remodeling.
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Review Comparative Study
How to explain the differences between renin angiotensin system modulators.
Angiotensin II (Ang II) plays important roles in the development of cardiovascular diseases including hypertension, renal diseases, cardiac hypertrophy, congestive heart failure, and ischemic heart disease. Angiotensin II exerts classic hemodynamic and renal effects, but it is also a local biologically active mediator with direct effects on endothelial and smooth muscle cells. Two subtypes of Ang II receptors, type 1 (AT(1)) and type 2 (AT(2)), have been identified. ⋯ Thus, pharmacologic blockade of the AT(1) receptor and resulting overactivation of AT(2) receptors could impair or delay neovascularization in ischemic tissues in patients receiving chronic treatment with angiotensin receptor blockers. In contrast, increased tissue bradykinin resulting from inhibition of converting enzyme could help to restore functional vascularization in ischemic tissues. These basic concepts deserve a second reading and reevaluation to discuss differences in vascular protection in large clinical trials with different classes of drugs acting on the renin-angiotensin system.
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To assess the interchangeability of carotid tonometry and synthesized aorta pressure waveforms for estimating central systolic blood pressure (SBP) and augmentation index (AIx). ⋯ The use of a generalized TFF in combination with well-calibrated radial pressure curves yields estimates of SBP in good agreement with carotid tonometry. Although AIx derived from a measured radial pressure curve correlates surprisingly closely with AIx measured on a synthesized aortic pressure curve, the correlation with a directly measured AIx on carotid signals is relatively poor.