University of Konstanz

About: University of Konstanz is a education organization based out in Konstanz, Baden-Württemberg, Germany. It is known for research contribution in the topics: Population & Membrane. The organization has 12115 authors who have published 27401 publications receiving 951162 citations. The organization is also known as: University of Constance & Universität Konstanz.

Enhanced peroxynitrite formation is associated with vascular aging.

Abstract: Vascular aging is mainly characterized by endothelial dysfunction. We found decreased free nitric oxide (NO) levels in aged rat aortas, in conjunction with a sevenfold higher expression and activity of endothelial NO synthase (eNOS). This is shown to be a consequence of age-associated enhanced superoxide (·O2−) production with concomitant quenching of NO by the formation of peroxynitrite leading to nitrotyrosilation of mitochondrial manganese superoxide dismutase (MnSOD), a molecular footprint of increased peroxynitrite levels, which also increased with age. Thus, vascular aging appears to be initiated by augmented ·O2− release, trapping of vasorelaxant NO, and subsequent peroxynitrite formation, followed by the nitration and inhibition of MnSOD. Increased eNOS expression and activity is a compensatory, but eventually futile, mechanism to counter regulate the loss of NO. The ultrastructural distribution of 3-nitrotyrosyl suggests that mitochondrial dysfunction plays a major role in the vascular aging process.

Recovering Risk Aversion from Option Prices and Realized Returns

Abstract: A relationship exists between aggregate risk-neutral and subjective probability distributions and risk aversion functions. We empirically derive risk aversion functions implied by option prices and realized returns on the S&P 500 index simultaneously. These risk aversion functions dramatically change shapes around the 1987 crash: Precrash, they are positive and decreasing in wealth and largely consistent with standard economic theory. Postcrash, they are partially negative and partially increasing and irreconcilable with the theory. Mispricing in the option market is the most likely cause. A simulated trading strategy exploiting this mispricing shows excess returns even after accounting for the possibility of further crashes, transaction costs, and hedges against the downside risk.

Cathepsin B Acts as a Dominant Execution Protease in Tumor Cell Apoptosis Induced by Tumor Necrosis Factor

Abstract: Death receptors can trigger cell demise dependent or independent of caspases In WEHI-S fibrosarcoma cells, tumor necrosis factor (TNF) induced an increase in cytosolic cathepsin B activity followed by death with apoptotic features Surprisingly, this process was enhanced by low, but effectively inhibiting, concentrations of pan-caspase inhibitors Contrary to caspase inhibitors, a panel of pharmacological cathepsin B inhibitors, the endogenous cathepsin inhibitor cystatin A as well as antisense-mediated depletion of cathepsin B rescued WEHI-S cells from apoptosis triggered by TNF or TNF-related apoptosis-inducing ligand Thus, cathepsin B can take over the role of the dominant execution protease in death receptor-induced apoptosis The conservation of this alternative execution pathway was further examined in other tumor cell lines Here, cathepsin B acted as an essential downstream mediator of TNF-triggered and caspase-initiated apoptosis cascade, whereas apoptosis of primary cells was only minimally dependent on cathepsin B These data imply that cathepsin B, which is commonly overexpressed in human primary tumors, may have two opposing roles in malignancy, reducing it by its proapoptotic features and enhancing it by its known facilitation of invasion

Improved auditory spatial tuning in blind humans

Abstract: Despite reports of improved auditory discrimination capabilities in blind humans1,2,3 and visually deprived animals4, there is no general agreement as to the nature or pervasiveness of such compensatory sensory enhancements5. Neuroimaging studies have pointed out differences in cerebral organization between blind and sighted humans6,7,8,9,10,11,12, but the relationship between these altered cortical activation patterns and auditory sensory acuity remains unclear. Here we compare behavioural and electrophysiological indices of spatial tuning within central and peripheral auditory space in congenitally blind and normally sighted but blindfolded adults to test the hypothesis (raised by earlier studies of the effects of auditory deprivation on visual processing13,14) that the effects of visual deprivation might be more pronounced for processing peripheral sounds. We find that blind participants displayed localization abilities that were superior to those of sighted controls, but only when attending to sounds in peripheral auditory space. Electrophysiological recordings obtained at the same time revealed sharper tuning of early spatial attention mechanisms in the blind subjects. Differences in the scalp distribution of brain electrical activity between the two groups suggest a compensatory reorganization of brain areas in the blind that may contribute to the improved spatial resolution for peripheral sound sources.