Showing papers by "Hans Ackerman published in 2015"
TL;DR: A community-based case-control study of Gambian children was carried out to determine whether ADMA and arginine homeostasis is disrupted during severe or uncomplicated malaria infections and to test the hypothesis that DDAH1 is inactivated during Plasmodium infection.
Abstract: Inhibition of nitric oxide (NO) signaling may contribute to pathological activation of the vascular endothelium during severe malaria infection. Dimethylarginine dimethylaminohydrolase (DDAH) regulates endothelial NO synthesis by maintaining homeostasis between asymmetric dimethylarginine (ADMA), an endogenous NO synthase (NOS) inhibitor, and arginine, the NOS substrate. We carried out a community-based case-control study of Gambian children to determine whether ADMA and arginine homeostasis is disrupted during severe or uncomplicated malaria infections. Circulating plasma levels of ADMA and arginine were determined at initial presentation and 28 days later. Plasma ADMA/arginine ratios were elevated in children with acute severe malaria compared to 28-day follow-up values and compared to children with uncomplicated malaria or healthy children (p<0.0001 for each comparison). To test the hypothesis that DDAH1 is inactivated during Plasmodium infection, we examined DDAH1 in a mouse model of severe malaria. Plasmodium berghei ANKA infection inactivated hepatic DDAH1 via a post-transcriptional mechanism as evidenced by stable mRNA transcript number, decreased DDAH1 protein concentration, decreased enzyme activity, elevated tissue ADMA, elevated ADMA/arginine ratio in plasma, and decreased whole blood nitrite concentration. Loss of hepatic DDAH1 activity and disruption of ADMA/arginine homeostasis may contribute to severe malaria pathogenesis by inhibiting NO synthesis.
20 citations
TL;DR: The observed temporal and spatial diversity of blood-flow-derived forearm temperature allow consideration of thermal-imaging guided placement of skin sensors to achieve enhanced sensitivity in monitoring of skin hemodynamics.
Abstract: Continuous infrared imaging revealed transient changes in forearm temperature during arterial occlusion, reperfusion, and recovery in a healthy subject group. Processing the imaging data with the k-means algorithm further revealed reactive vascular sites in the skin with rapid or delayed temperature amplification. The observed temporal and spatial diversity of blood-flow-derived forearm temperature allow consideration of thermal-imaging guided placement of skin sensors to achieve enhanced sensitivity in monitoring of skin hemodynamics.
7 citations