University of Duisburg-Essen

About: University of Duisburg-Essen is a education organization based out in Essen, Nordrhein-Westfalen, Germany. It is known for research contribution in the topics: Population & Transplantation. The organization has 16072 authors who have published 39972 publications receiving 1109199 citations.

Does a ‘volume-filling effect’ always prevent chemotactic collapse?

Abstract: The parabolic-parabolic Keller-Segel system for chemotaxis phenomena, {u t =∇ · (φ(u)∇u)-∇ · (ψ(u)∇ v ), x∈Ω, t>0 v t =Δv-v+u, x∈Ω, t>0 is considered under homogeneous Neumann boundary conditions in a smooth bounded domain Ω ⊂ ℝ n with n≥2. It is proved that if ψ(u)/φ(u) grows faster than u 2/n as u → ∞ and some further technical conditions are fulfilled, then there exist solutions that blow up in either finite or infinite time. Here, the total mass ∫ Ω u(x,t)dx may attain arbitrarily small positive values. In particular, in the framework of chemotaxis models incorporating a volume-filling effect in the sense of Painter and Hillen (Can. Appl. Math. Q. 2002; 10(4):501-543), the results indicate how strongly the cellular movement must be inhibited at large cell densities in order to rule out chemotactic collapse.

A Functional Role for Antibodies in Tuberculosis

Abstract: While a third of the world carries the burden of tuberculosis, disease control has been hindered by a lack of tools, including a rapid, point-of-care diagnostic and a protective vaccine. In many infectious diseases, antibodies (Abs) are powerful biomarkers and important immune mediators. However, in Mycobacterium tuberculosis (Mtb) infection, a discriminatory or protective role for humoral immunity remains unclear. Using an unbiased antibody profiling approach, we show that individuals with latent tuberculosis infection (Ltb) and active tuberculosis disease (Atb) have distinct Mtb-specific humoral responses, such that Ltb infection is associated with unique Ab Fc functional profiles, selective binding to FcγRIII, and distinct Ab glycosylation patterns. Moreover, compared to Abs from Atb, Abs from Ltb drove enhanced phagolysosomal maturation, inflammasome activation, and, most importantly, macrophage killing of intracellular Mtb. Combined, these data point to a potential role for Fc-mediated Ab effector functions, tuned via differential glycosylation, in Mtb control.

Oxidized Ca(2+)/calmodulin-dependent protein kinase II triggers atrial fibrillation.

Abstract: Background—Atrial fibrillation (AF) is a growing public health problem without adequate therapies. Angiotensin II and reactive oxygen species are validated risk factors for AF in patients, but the molecular pathways connecting reactive oxygen species and AF are unknown. The Ca2+/calmodulin-dependent protein kinase II (CaMKII) has recently emerged as a reactive oxygen species–activated proarrhythmic signal, so we hypothesized that oxidized CaMKIIδ could contribute to AF. Methods and Results—We found that oxidized CaMKII was increased in atria from AF patients compared with patients in sinus rhythm and from mice infused with angiotensin II compared with mice infused with saline. Angiotensin II–treated mice had increased susceptibility to AF compared with saline-treated wild-type mice, establishing angiotensin II as a risk factor for AF in mice. Knock-in mice lacking critical oxidation sites in CaMKIIδ (MM-VV) and mice with myocardium-restricted transgenic overexpression of methionine sulfoxide reductase A, ...