Horst Baumgärtl

Learn More
It has been known since 1851 that atmospheric oxygen is taken up by the human epidermis. The contribution to total respiration is negligible. Until now the significance for the local oxygen supply of the skin has remained unknown. With a newly developed sensor, the oxygen fluxoptode, it has become possible to make local measurements of the transcutaneous(More)
BACKGROUND The spontaneously hypertensive rat (SHR) has oxidative stress and enhanced O2 usage (Q(O2)) relative to tubular sodium transport (TNa). Angiotensin II (Ang II) acting on Type I receptors (AT1-R) causes renal oxidative stress and functional nitric oxide (NO) deficiency that could enhance O2 usage. Therefore, we investigated the hypothesis that(More)
BACKGROUND The kidney has a high rate of oxygen usage (QO2) that is closely dependent on tubular Na+ transport (TNa). However, little is known concerning the regulation of the cortical partial pressure of oxygen (pO2). METHODS First, the pO2 was measured in the outer cortical proximal (PT) and distal tubules (DT), efferent arterioles (EA), and superficial(More)
Oxygen concentrations were measured in single Ca-alginate beads using polarographic microneedle electrodes. To obtain reliable results the effects of mechanical pressure on the electrode as well as the influence of free Ca2+-ions had to be compensated. No oxygen gradients were detectable in cell-free alginate beads, whereas in beads with entrapped cells(More)
Using a newly developed platinum-O2-microeletrode [30] based on the design ofSilver [37] the construction and properties of which are described,pO2-measurements in the parenchyma of the blood-perfused and the cell-free perfused rat kidney were carried out. By continuous recording of thepO2 during slow (150 μ×min−1) insertion of the O2-electrode into the(More)
The O2 supply of the blood-free perfused brain cortex of the guinea pig was investigated by measuring polarographically the local distribution of tissue $$P_{O_2 }$$ at 18°C, 24°C, and 37°C. The perfusion was performed in situ, using a medium equilibrated by a gas mixture of 95% O2 and 5% CO2. Papaverine was added to prevent vasoconstriction during(More)
The relationship between tissue oxygen partial pressure (pO2) values and electrical activities of guinea pig olfactory cortical slices was investigated as the slices were superfused with Krebs-Ringer's solution equilibrated with different gas mixtures. ThepO2 values were measured in the slices with oxygen microelectrodes (tip diameter <1 μm). 1. Studies(More)
The O2 diffusion field within an agarose medium in front of a 1.5 mm platinum macroelectrode with plane and circular surface was measured by means of a platinum microelectrode (Pt diameter of ca. 0.3 μm). The $$P_{O_2 }$$ profiles measured in different parts of the O2 diffusion field agree very well with the theoretically calculated values. Under conditions(More)
Although blood flow to the renal cortex is high and oxygen extraction is low, the renal cortex is remarkably susceptible to hypoxia. Because erythropoietin production has been localized mainly to the renal cortex, the aim of this study was to find a common denominator for both the high susceptibility to hypoxia and oxygen sensing within the renal cortex. By(More)