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.

Primary structure of Torpedo marmorata chloride channel isolated by expression cloning in Xenopus oocytes.

Abstract: A complementary DNA encoding a voltage-gated chloride channel from Torpedo marmorata electric organ was cloned by expressing hybrid-depleted messenger RNA in Xenopus oocytes. The predicted protein has a sequence of 805 amino acids containing several putative membrane-spanning domains. Expression of the protein in Xenopus oocytes shows that it is sufficient for channel function.

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.

Observation of quantum jumps.

Abstract: We have recorded the laser-excited resonance fluorescence of one to three ${\mathrm{Ba}}^{+}$ ions and observed Bohr's "quantum jumps" when an ion decayed to the metastable $^{2}D_{\frac{5}{2}}$ state, suddenly quenching its fluorescence. Most of the jumps mark Raman-Stokes scattering from the $^{2}S_{\frac{1}{2}}$ and $^{2}D_{\frac{3}{2}}$ levels.