University of Hamburg

About: University of Hamburg is a education organization based out in Hamburg, Germany. It is known for research contribution in the topics: Population & Laser. The organization has 45564 authors who have published 89286 publications receiving 2850161 citations. The organization is also known as: Hamburg University.

Mutations in the deubiquitinase gene USP8 cause Cushing's disease

Abstract: Cushing's disease is caused by corticotroph adenomas of the pituitary. To explore the molecular mechanisms of endocrine autonomy in these tumors, we performed exome sequencing of 10 corticotroph adenomas. We found somatic mutations in the USP8 deubiquitinase gene in 4 of 10 adenomas. The mutations clustered in the 14-3-3 protein binding motif and enhanced the proteolytic cleavage and catalytic activity of USP8. Cleavage of USP8 led to increased deubiqutination of the EGF receptor, impairing its downregulation and sustaining EGF signaling. USP8 mutants enhanced promoter activity of the gene encoding proopiomelanocortin. In summary, our data show that dominant mutations in USP8 cause Cushing's disease via activation of EGF receptor signaling.

Direct Evidence for Spinal Cord Involvement in Placebo Analgesia

Abstract: Placebo analgesia is a prime example of the impact that psychological factors have on pain perception. We used functional magnetic resonance imaging of the human spinal cord to test the hypothesis that placebo analgesia results in a reduction of nociceptive processing in the spinal cord. In line with behavioral data that show decreased pain responses under placebo, pain-related activity in the spinal cord is strongly reduced under placebo. These results provide direct evidence for spinal inhibition as one mechanism of placebo analgesia and highlight that psychological factors can act on the earliest stages of pain processing in the central nervous system.

Size and surface effects on the MRI relaxivity of manganese ferrite nanoparticle contrast agents.

Abstract: Superparamagnetic MnFe2O4 nanocrystals of different sizes were synthesized in high-boiling ether solvent and transferred into water using three different approaches. First, we applied a ligand exchange in order to form a water soluble polymer shell. Second, the particles were embedded into an amphiphilic polymer shell. Third, the nanoparticles were embedded into large micelles formed by lipids. Although all approaches lead to effective negative contrast enhancement, we observed significant differences concerning the magnitude of this effect. The transverse relaxivity, in particular r2*, is greatly higher for the micellar system compared to the polymer-coated particles using same-sized nanoparticles. We also observed an increase in transverse relaxivities with increasing particle size for the polymer-coated nanocrystals. The results are qualitatively compared with theoretical models describing the dependence of relaxivity on the size of magnetic spheres.

Autonomy and Competence in German and American University Students: A Comparative Study Based on Self-Determination Theory.

Abstract: According to self-determination theory (R M Ryan & E L Deci, 2000), supports for autonomy and competence are essential for growth and well-being in any learning environment Educational contexts differ in their relative support for these 2 needs The authors examined the role of autonomy and competence in 2 German and 2 American university settings, as they were predicted to differ in terms of their relative emphasis on competence versus autonomy Invariance analyses supported the construct comparability of the measures and demonstrated that German students felt significantly more autonomous and less competent than American students Perceived pressures and positive informational feedback were modeled as antecedents of autonomy and competence, and well-being was examined as a consequence The hypothesized model was generally supported across the 4 samples