University of Tübingen

About: University of Tübingen is a education organization based out in Tübingen, Germany. It is known for research contribution in the topics: Population & Immune system. The organization has 40555 authors who have published 84108 publications receiving 3015320 citations. The organization is also known as: Eberhard Karls University & Eberhard-Karls-Universität Tübingen.

Ethylene-induced stomatal closure in Arabidopsis occurs via AtrbohF-mediated hydrogen peroxide synthesis

Abstract: Ethylene is a plant hormone that regulates many aspects of growth and development. Despite the well-known association between ethylene and stress signalling, its effects on stomatal movements are largely unexplored. Here, genetic and physiological data are provided that position ethylene into the Arabidopsis guard cell signalling network, and demonstrate a functional link between ethylene and hydrogen peroxide (H(2)O(2)). In wild-type leaves, ethylene induces stomatal closure that is dependent on H(2)O(2) production in guard cells, generated by the nicotinamide adenine dinucleotide phosphate hydrogen (NADPH) oxidase AtrbohF. Ethylene-induced closure is inhibited by the ethylene antagonists 1-MCP and silver. The ethylene receptor mutants etr1-1 and etr1-3 are insensitive to ethylene in terms of stomatal closure and H(2)O(2) production. Stomata of the ethylene signalling ein2-1 and arr2 mutants do not close in response to either ethylene or H(2)O(2) but do generate H(2)O(2) following ethylene challenge. Thus, the data indicate that ethylene and H(2)O(2) signalling in guard cells are mediated by ETR1 via EIN2 and ARR2-dependent pathway(s), and identify AtrbohF as a key mediator of stomatal responses to ethylene.

Identification and characterization of metabolically benign obesity in humans.

Abstract: Background: Obesity represents a risk factor for insulin resistance, type 2 diabetes mellitus, and atherosclerosis. In addition, for any given amount of total body fat, an excess of visceral fat or fat accumulation in the liver and skeletal muscle augments the risk. Conversely, even in obesity, a metabolically benign fat distribution phenotype may exist. Methods: In 314 subjects, we measured total body, visceral, and subcutaneous fat with magnetic resonance (MR) tomography and fat in the liver and skeletal muscle with proton MR spectroscopy. Insulin sensitivity was estimated from oral glucose tolerance test results. Subjects were divided into 4 groups: normal weight (body mass index [BMI] [calculated as weight in kilograms divided by height in meters squared], 25.0), overweight (BMI, 25.0-29.9), obese–insulin sensitive (IS) (BMI, 30.0 and placement in the upper quartile of insulin sensitivity), and obese–insulin resistant (IR) (BMI, 30.0 and placement in the lower 3 quartiles of insulin sensitivity). Results: Total body and visceral fat were higher in the overweight and obese groups compared with the normal-weight group (P.05); however, no differences were observed between the obese groups. In contrast, ectopic fat in skeletal muscle (P.001) and particularly the liver (4.3%±0.6% vs 9.5%±0.8%)andtheintima-mediathicknessofthecommon carotidartery(0.54±0.02vs0.59±0.01mm)werelowerand insulin sensitivity was higher (17.4±0.9 vs 7.3±0.3 arbitrary units) in the obese-IS vs the obese-IR group (P.05). Unexpectedly, the obese-IS group had almost identical insulin sensitivity and the intima-media thickness was not statistically different compared with the normal-weight group (18.2±0.9 AU and 0.51±0.02 mm, respectively). Conclusions: A metabolically benign obesity that is not accompanied by insulin resistance and early atherosclerosis exists in humans. Furthermore, ectopic fat in the liver may be more important than visceral fat in the determination of such a beneficial phenotype in obesity.

Dermoscopy of pigmented skin lesions: results of a consensus meeting via the Internet

Abstract: Background: There is a need for better standardization of the dermoscopic terminology in assessing pigmented skin lesions. Objective: The virtual Consensus Net Meeting on Dermoscopy was organized to investigate reproducibility and validity of the various features and diagnostic algorithms. Methods: Dermoscopic images of 108 lesions were evaluated via the Internet by 40 experienced dermoscopists using a 2-step diagnostic procedure. The first-step algorithm distinguished melanocytic versus nonmelanocytic lesions. The second step in the diagnostic procedure used 4 algorithms (pattern analysis, ABCD rule, Menzies method, and 7-point checklist) to distinguish melanoma versus benign melanocytic lesions. κ Values, log odds ratios, sensitivity, specificity, and positive likelihood ratios were estimated for all diagnostic algorithms and dermoscopic features. Results: Interobserver agreement was fair to good for all diagnostic methods, but it was poor for the majority of dermoscopic criteria. Intraobserver agreement was good to excellent for all algorithms and features considered. Pattern analysis allowed the best diagnostic performance (positive likelihood ratio: 5.1), whereas alternative algorithms revealed comparable sensitivity but less specificity. Interobserver agreement on management decisions made by dermoscopy was fairly good (mean κ value: 0.53). Conclusion: The virtual Consensus Net Meeting on Dermoscopy represents a valid tool for better standardization of the dermoscopic terminology and, moreover, opens up a new territory for diagnosing and managing pigmented skin lesions. (J Am Acad Dermatol 2003;48:679-93.) J Am Acad Dermatol 2003;48:679-93.