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.

Vascular wall resident progenitor cells: a source for postnatal vasculogenesis.

Abstract: Here, we report the existence of endothelial precursor (EPC) and stem cells in a distinct zone of the vascular wall that are capable to differentiate into mature endothelial cells, hematopoietic and local immune cells, such as macrophages. This zone has been identified to be localized between smooth muscle and adventitial layer of human adult vascular wall. It predominantly contains CD34-positive (+) but CD31-negative (-) cells, which also express VEGFR2 and TIE2. Only few cells in this zone of the vascular wall are positive for CD45. In a ring assay using the fragments of human internal thoracic artery (HITA), we show here that the CD34+ cells of the HITA-wall form capillary sprouts ex vivo and are apparently recruited for capillary formation by tumor cells. New vessels formed by these vascular wall resident EPCs express markers for angiogenically activated endothelial cells, such as CEACAM1, and also for mature endothelial cells, such as VE-cadherin or occludin. Vascular wall areas containing EPCs are found in large and middle sized arteries and veins of all organs studied here. These data suggest the existence of a ;vasculogenic zone' in the wall of adult human blood vessels, which may serve as a source for progenitor cells for postnatal vasculogenesis, contributing to tumor vascularization and local immune response.

Disruption of the mouse L1 gene leads to malformations of the nervous system

Abstract: The adhesion molecule L1 is a member of the immunoglobulin super-family1. L1 is involved in various recognition processes in the CMS and PNS2–3, and binding to L1 can activate signal transduction pathways4,5. Mutations in the human L1 gene are associated with a variable phenotype, including mental retardation and anomalous development of the nervous system, referred to as ‘CRASH’ (corpus callosum hypoplasia, retardation, adducted thumbs, spastic paraplegia, and hydrocephalus)6. We generated an animal model of these conditions by gene targeting. Mutant mice were smaller than wild-type and were less sensitive to touch and pain, and their hind-legs appeared weak and uncoordinated. The size of the corticospinal tract was reduced and, depending on genetic background, the lateral ventricles were often enlarged. Non-myelinating Schwann cells formed processes not associated with axons and showed reduced association with axons. In vitro, neurite outgrowth on an L1 substrate and fasciculation were impaired. The mutant mouse described here will help to elucidate the functions of L1 in the nervous system and how these depend on genetic influences.

Colloidal Synthesis and Self-Assembly of CoPt3 Nanocrystals

Abstract: Reduction of platinum acetylacetonate and thermodecomposition of cobalt carbonyl in the presence of 1-adamantanecarboxylic acid were employed in different coordinating mixtures to produce monodisperse, highly crystalline CoPt3 nanoparticles. The mean particle size can be varied from 1.5 to 7.2 nm by controlling the reaction conditions and the type of coordinating mixture. As-synthesized CoPt3 particles represent single crystal domains and have chemically disordered face-centered cubic (fcc) structure. Nearly spherical CoPt3 nanocrystals were found to assemble into two- (2D) and three-dimensional (3D) structures. An AB5 type superlattice is observed by TEM after mixing two nanoparticle samples with different mean sizes. Slow precipitation led to the formation of facetted colloidal crystals with sizes up to 20 μm.

Nitinol Stent Implantation Versus Percutaneous Transluminal Angioplasty in Superficial Femoral Artery Lesions up to 10 cm in Length The Femoral Artery Stenting Trial (FAST)

Abstract: Background— Endoluminal treatment of superficial femoral artery lesions is a matter of controversy. The present study was designed to investigate the impact of nitinol stenting of superficial femor...

Field-dependent size and shape of single magnetic Skyrmions.

Abstract: The atomic-scale spin structure of individual isolated Skyrmions in an ultrathin film is investigated in real space by spin-polarized scanning tunneling microscopy. Their axial symmetry as well as their unique rotational sense is revealed by using both out-of-plane and in-plane sensitive tips. The size and shape of Skyrmions change as a function of the magnetic field. An analytical expression for the description of Skyrmions is proposed and applied to connect the experimental data to the original theoretical model describing chiral Skyrmions. Thereby, the relevant material parameters responsible for Skyrmion formation can be obtained.