It is known that Cys beta 93 in hemoglobin A reacts with sulfhydryl reagents more rapidly in the oxy than in the deoxy form. In this study, the reaction of the residues toward 4,4'-dithiodipyridine was measured at various degrees of saturation with O2. Analysis of initial rates of the reaction revealed that an intermediate, which reacts even more rapidly than the oxy form, occurs in the course ...

The oxygenation state of myoglobin and the redox state of cytochrome c provide information on the[Formula: see text] in the cytosol and mitochondria, respectively. An optical "window" from ∼540 to 585 nm was found in the pig heart in vivo that permitted the monitoring of myoglobin and cytochrome c without interference from Hb oxygenation or blood volume. Scanning reflectance spectroscopy was pe...

Arai, Andrew E., Claudia E. Kasserra, Paul R. Territo, Amir H. Gandjbakhche, and Robert S. Balaban. Myocardial oxygenation in vivo: optical spectroscopy of cytoplasmic myoglobin and mitochondrial cytochromes. Am. J. Physiol. 277 (Heart Circ. Physiol. 46): H683–H697, 1999.— The oxygenation state of myoglobin and the redox state of cytochrome c provide information on the PO2 in the cytosol and mi...

Whole blood oxygen equilibrium curves (O2 ECs), blood buffer lines, and several hematologic properties were determined for adult guinea pigs exposed to 700 ppm methyl isocyanate (MIC) for 15 min. MIC inhalation effected a significant reduction of blood O2 affinity; the half-saturation pressure (P50) at 38 degrees C increased from the control (untreated) level of 22.8 +/- 0.1 mm Hg to values ran...

The role of the adrenergic nervous system in the response to coronary artery occlusion has been examined using surgical and chemical denervation techniques. Experiments were conducted on four groups of dogs (n = 18): 1) untreated controls; 2) intrapericardial denervation immediately prior to coronary ligation; 3) surgical denervation 2 weeks prior to the experiment; and 4) chemical sympathectom...

To examine the possible relationship between systemic HT and SAS we compared 21 hypertensive (HT+) and 29 normotensive (HT-) patients for morphologic characteristics, sleep disturbances and respiratory events monitored during a full night polysomnography. There was no significant difference between HT+ and HT- patients with respect to age, weight, BMI, sleep stage distribution and disorganizati...

Background Dependence of blood T2 on O2 saturation has led to noninvasive MRI-based techniques for determining venous O2 saturation (SvO2) [1-3]. However, applying a general calibration factor derived from in vitro experiments can lead to inaccurate and largely varying SvO2 estimates in the target population. We aim to show that based on the Luz-Meiboom relation 1/T2 = 1/T2o + Hct(1-Hct) τex [(...

Neuronal nitric-oxide synthase (NOS-1) is a hemeprotein that generates NO and citrulline from L-arginine, O2, and NADPH. During catalysis, a majority of NOS-1 binds self-generated NO and converts to a ferrous-NO complex, which causes it to operate at a fraction of its maximum possible activity during the steady state (Abu-Soud, H. M., Wang, J., Rousseau, D. L., Fukuto, J., Ignarro, L. J., and S...

We hypothesized that near-infrared spectroscopy (NIRS) measures of hemoglobin and/or myoglobin O2 saturation (IR-SO2) in the vascular bed of exercising muscle would parallel changes in femoral venous O2 saturation (SfvO2) at the onset of leg-kicking exercise in humans. Six healthy subjects performed transitions from rest to 48 +/- 3 (SE)-W two-legged kicking exercise while breathing 14, 21, or ...