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We have measured depth profiles of extracellular pH (pHECR) and PO2 (PtO2) as well as the kinetics of changes of pHECR in the isolated brain stem-spinal cord preparation of the neonatal rat using pH and PO2 microelectrodes that entered from the ventral surface. When the preparation was superfused with control mock cerebrospinal fluid (Control mock CSF; pH =(More)
Type-I cells (from rabbit embryos) in primary culture were studied in voltage-clamp experiments using the whole cell arrangement of the patch-clamp technique. With a pipette solution containing 130 mM K+ and 3 mM Mg-ATP, large outward currents were obtained positive to a threshold of about -30 mV by clamping cells from -50 mV to different test pulses (-80(More)
Current concepts of cellular oxygen-sensing include an isoform of the neutrophil NADPH oxidase, different electron carrier units of the mitochondrial electron transport chain (ETC), heme oxygenase-2 (HO-2), and a subfamily of 2-oxoglutarate dependent dioxygenases termed HIF (hypoxia inducible factor) prolyl hydroxylases (PHDs) and HIF asparagyl hydroxylase(More)
  • Helmut Acker
  • 2005
Structural and functional integrity of organ function profoundly depends on a regular oxygen and glucose supply. Any disturbance of this supply becomes life threatening and may result in severe loss of organ function. Particular reductions in oxygen availability (hypoxia) caused by respiratory or blood circulation irregularities cannot be tolerated for(More)
Blastocyst-derived pluripotent mouse embryonic stem cells can differentiate in vitro to form so-called embryoid bodies (EBs), which recapitulate several aspects of murine embryogenesis. We used this in vitro model to study oxygen supply and consumption as well as the response to reduced oxygenation during the earliest stages of development. EBs were found(More)
The adenosine triphosphate (ATP) level in the carotid body has often been discussed as the crucial step in the chemoreceptive process. Therefore, the ATP level of the cat carotid body was investigated with the aid of the bioluminescence method under different stimulation conditions. Under normoxic conditions an ATP level of about 0.087 nmol/glomus was(More)
pH gradients were measured with microelectrodes in cellular spheroids of human glioma (U-118 MG) and thyroid carcinoma (HTh7) origin. pH decreased outside the spheroids and then continuously decreased when the electrode was moved through the spheroid towards the center. The lowest pH values inside the spheroids were in the range 6.7-6.8 when grown under(More)
Two human neuroblastoma (NB) cell lines, SH-SY5Y and Kelly, were found to express the gene for erythropoietin (EPO) in an oxygen (O(2))-dependent manner. However, NB cells had maximal production of EPO with lower partial pressure of O(2) values than the well-characterized hepatoma cell line HepG2. This maximal EPO expression was preceded by accumulation of(More)
For many years there has been a concern that anoxic and, therefore, radioresistant cells in tumours might escape radio-therapeutic treatment. This has been demonstrated for experimental tumours, but more data are needed on this question for human tumours (Andrews, 1978). To acquire knowledge on oxygen metabolism and its relation to radio-senstivity, cell(More)
Autofluorescence (AF) originating from the cytoplasmic region of mammalian cells has been thoroughly investigated; however, AF from plasma membranes of viable intact cells is less well known, and has been mentioned only in a few older publications. Herein, we report results describing single- and two-photon spectral properties of a strong yellowish-green AF(More)