Markus Boettcher

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The pH is an important parameter controlling many metabolic and signalling pathways in living cells. Recombinant fluorescent pH indicators (pHluorins) have come into vogue for monitoring cellular pH. They are derived from the most popular Aequorea victoria GFP (Av- GFP). Here, we present a novel fluorescent pH reporter protein from the orange seapen(More)
The endothelium-derived hyperpolarizing factor (EDHF) contributes critically to the regulation of vascular tone. Its dependency on direct signaling through myoendothelial gap junctions composed of connexins (Cx) is controversially discussed. We studied the impact of Cx40 in EDHF-type dilations in vivo and in vitro (wire and pressure myography) in small(More)
Gap junctions are formed in the cardiovascular system by connexin40 (Cx40), Cx37, Cx43, and Cx45. These low resistance channels allow the transfer of ions and small molecules between cells. The longitudinal coupling of endothelial and smooth muscle cells via gap junctions allows the spread of changes in membrane potential along the vascular wall and hence(More)
We describe the versatile features of the attosecond beamline recently installed at CEA-Saclay on the PLFA kHz laser. It combines a fine and very complete set of diagnostics enabling high harmonic spectroscopy (HHS) through the advanced characterization of the amplitude, phase, and polarization of the harmonic emission. It also allows a variety of(More)
We introduce a methodology for analysis of multiwavelength data from X-ray selected BL Lac (XBL) objects detected in the TeV regime. By assuming that the radio–through–X-ray flux from XBLs is nonthermal synchrotron radiation emitted by isotropically-distributed electrons in the randomly oriented magnetic field of a relativistic blazar jet, we obtain the(More)
The time and angle dependent line and continuum emission from a dense torus around a cosmological gamma-ray burst source is simulated, taking into account photoionization, collisional ionization, recombination, and electron heating and cooling due to various processes. The importance of the hydrodynamical interaction between the torus and the expanding(More)
UNLABELLED PET with 13N-ammonia permits the noninvasive quantification of myocardial blood flow (MBF) in humans. The present study was done to assess the reproducibility of quantitative blood flow measurements at rest and during pharmacologically induced hyperemia in healthy individuals. METHODS Thirty healthy volunteers (26 men, 4 women) were studied.(More)
BACKGROUND This investigation examines the effects of inotropic stimulation on myocardial blood flow (MBF) and glucose metabolism (MRGlc) in dysfunctional myocardium through the use of positron emission tomography (PET). METHODS AND RESULTS Nineteen patients with chronic coronary artery disease and 12 normal volunteers were studied with 13N-ammonia,(More)
Gap junctions interconnect vascular cells homocellularly, thereby allowing the spread of signals along the vessel wall, which serve to coordinate vessel behavior. In addition, gap junctions provide heterocellular coupling between endothelial and vascular smooth muscle cells, creating so-called myoendothelial gap junctions (MEGJs). Endothelial cells control(More)
BACKGROUND Cigarette smoking is a major preventable risk factor for coronary artery disease and sudden cardiac death. However, the effect of acute and long-term cigarette smoking on coronary vasodilatory capacity and myocardial flow reserve has not been quantified in humans. METHODS AND RESULTS To examine the effect of short-term and long-term smoking,(More)