Learn More
Oxygen-dependent quenching of phosphorescence has been used to measure the dependence of mitochondrial oxidative phosphorylation on oxygen concentration in suspensions of isolated rat liver mitochondria. An instrument has been designed which simultaneously monitors the phosphorescence lifetime of a fluorophor and the reduction of cytochrome c by dual(More)
Changes in cerebral blood flow (CBF) using laser-Doppler and microvascular O2 oxygen tension using oxygen-dependent phosphorescence quenching in the rat somatosensory cortex were obtained during electrical forepaw stimulation. The signal-averaged CBF response resulting from electrical forepaw stimulation consisted of an initial peak (t = 3.1 +/- 0.8 seconds(More)
The oxygen dependence of mitochondrial respiration was investigated using suspensions of mitochondria and quiescent ventricular myocytes isolated from adult rat hearts. A new optical method was used to determine oxygen concentration in the suspending media. The P50 for respiration for coupled mitochondria at a high [ATP]/[ADP].[Pi] ratio and oxidizing(More)
To understand the interplay between microcirculatory control and carotid body (CB) function, we simultaneously measured carotid body microvascular PO2 (CBM PO2) and chemosensory activity in the cat in vivo under several experimental conditions. Cats were anesthetized with pentobarbital sodium, paralyzed, and artificially ventilated. CBs were exposed, and(More)
Oxygen-dependent quenching of phosphorescence is a function of the frequency of collision between the phosphor and molecular oxygen and of the efficiency of energy transfer during these collisions. Thus, quenching is dependent on the rate of diffusion of the phosphor and its molecular environment. For measurements in biological samples, the Pd-porphyrin is(More)
Oxygen-dependent quenching of phosphorescence is a useful and essentially noninvasive optical method for measuring oxygen in vivo and in vitro. Calibration of the phosphors is absolute, and once phosphors have been calibrated in one laboratory the same constants can be used by anyone else as long as the measurement is done under the same conditions. Two new(More)
INTRODUCTION Herpes simplex virus type 2 (HSV-2) facilitates sexual acquisition of HIV-1 but data on transmission are less clear. In this study the interaction between genital shedding of HIV-1 and HSV-2 was explored among Zimbabwean sex workers. METHODS Women (n = 214) were interviewed about genital symptoms. Blood samples were analysed for HIV-1 and(More)
Phosphorescence quenching techniques measure microvascular PO2 without direct surgical manipulation of the tissue. At a given arterial PO2, microvascular PO2 reflects the local O2 uptake-to-O2 delivery ratio, i.e., VO2/QO2. We evaluated the potential of phosphorescence quenching to determine microvascular PO2 in the rat costal diaphragm (PdiaO2). PdiaO2 and(More)