Increased PVP develops after isolated renal IRI, and macrophage-derived products are mediators in this response. These findings have implications for understanding the mechanisms underlying respiratory dysfunction associated with acute renal failure.

Background: Current guidelines recommend a diameter of 5-5.5 cm as the threshold for surgery on the ascending aorta. However, a study from the International Registry of Acute Aortic Dissection showed that nearly 60% occurred at <5.5 cm (the ‘aortic size paradox') - leading to a debate whether the size threshold should be lowered. However, the study showing dissection at small size had no knowledge of the population at risk. Herein, we aim to calculate the relative risk of aortic dissection at sizes <5.5 cm by analyzing both the number of occurring dissections (numerator) and the population at risk at each aortic size (denominator). Methods: Using a publicly available database of 3,573 multiethnic subjects (46% male, mean age 60.7 years) from the general population, we plotted a distribution curve of ascending aortic size (by magnetic resonance imaging). The relative risk of aortic dissection was calculated by dividing the proportion of dissections occurring at each size (numerator) by the proportion of aortas of that same size in the general population (denominator). Results: The mean ascending aortic diameter of the reference population was 3.2 cm (±0.4 cm). The largest diameter was 4.9 cm in women and 5.0 cm in men. The proportion of subjects with an aorta <3.5 cm was 79.2%, that of subjects with 3.5-3.9 cm was 18.0%, that of subjects with 4.0-4.4 cm was 2.6%, and that of subjects with ≥4.5 cm was 0.22%. The relative risk of dissection in those categories was found to be 0.055, 2.5, 4.9, and 346.8, respectively. Patients with an aorta ≥4.5 cm were 6,305 times more likely to suffer aortic dissection than those with an aorta <3.5 cm. Conclusions: The normal aorta is deceptively small, most commonly <3.5 cm. The aortic size paradox is a byproduct of the very large number of patients in small size ranges. This study fully supports current recommendations for surgical intervention at 5-5.5 cm.

Atrial natriuretic peptide (ANP) gene expression was localized in the rat gastric antrum using immunohistochemistry and in situ hybridization to mucosal cells in the lower portion of the antropyloric glands. Colocalization of immunoreactive ANP, long-acting natriuretic peptide, i.e., proANP-(1-30), and serotonin in these cells identified them to be enterochromaffin cells. Fasting for 72 h in 8-mo-old (adult) rats produced a significant (P < 0.05) decrease in the levels of ANP prohormone mRNA, immunoreactive proANP-(1-30) and ANP to approximately 33% of that of fed rats. Fasting in 1-mo-old rats had no effect on these parameters. Transcripts for natriuretic peptide receptor subtypes NPR-A, NPR-B, and NPR-C were found in both mucosa and muscle tissues of the antrum. ANP, brain natriuretic peptide (BNP), and C-type natriuretic peptide (CNP) stimulated the production of cGMP in antral mucosa in vitro with a potency of ANP > BNP >> CNP, suggesting that these receptors were functional. We conclude that fasting decreases ANP prohormone mRNA and its gene products, long-acting natriuretic peptide, and ANP in the antrum of adult rats.

ObjectiveTo determine if cross-tolerance to septic shock could be induced by a previous insult with sublethal hemorrhage (SLH) and to characterize the mechanisms involved in this induced protective response.

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