The deformability characteristics of isolated subpopulations of irreversibly sickled cells (ISC) have been studied in an ektacytometer. Analysis of laser diffraction patterns of well-oxygenated cells subjected to shear stress in solutions of varying osmolality has demonstrated a profound influence of mean corpuscular hemoglobin concentration and intracellular viscosity on the deformability of I...

We used near-infrared spectroscopy (NIRS) to study noninvasively the influence of aging on changes in the local concentration of oxygenated hemoglobin ([HbO2]), reduced hemoglobin ([HbR]), and total hemoglobin ([HbT] = [HbR] + [HbO2]) during activation of brain function. Young subjects (n = 12; age, 28 +/- 4 years) performing calculation tasks showed an increase in [HbO2] [mean (arbitrary units...

Hemoglobin (Hb) is an important component of red blood cells. This paper presents an optical non-contact technique that provides Hb concentration measurement. The absorption coefficient of blood differs at different wavelength this fact is used to calculate the optical characteristics of blood. In this newly developed system, absorption of light by oxygenated and deoxygenated hemoglobin is meas...

There is now a great deal of physical and chemical evidence that horse and human hemoglobins undergo a change of protein conformation on oxygenation.' 9 The molecular mechanism whereby these hemoglobins show cooperative or sigmoidal oxygen binding has remained obscure, however. In order to understand this "heme-heme" interaction, one must obtain structural information on partially oxygenated he...

One of the most intriguing phenomena associated with the function of hemoglobin is the reversible dissociation of protons which accompanies its oxygenation (2-4). This oxygen-linked ionization, which is commonly referred to as the Bohr effect, results in the liberation of about 2.7 protons per mole when human hemoglobin is oxygenated at physiological pH. Moreover, a “reverse Bohr effect” occurs...

A newly designed capillary deoxygenator has been constructed by using microporous polypropylene hollow fibers sealed into an airtight plexiglass housing. Oxygenated red cell suspensions and hemoglobin solutions flowing through the hollow fibers were subjected to deoxygenation with a gas mixture composed of 95 percent N2 and 5 percent CO2 passed through the housing. At a given flow rate of the o...

E VEBYO}TB KNOWS the distinction between the two kinds of disturbances in the acid-base metabolism: the respiratory, and the nonrespiratory-. Moreover, everyone agrees that the respiratory disturbances ought to be characterized by the CO2 tension of the arterial blood, as this tension is supposed to correspond with that of the alveolar air. When trying to characterize the nonrespiratory disturb...

That hypoxic tissues are more resistant to the effects of radiation than well-oxygenated tissues has been known for many decades, and repeated in vitro demonstrations have confirmed that to achieve the same degree of cytotoxicity, hypoxic cells require about three times the radiation dose that well-oxygenated cells need. Hypoxic cell sensitizers enhance the tissue response to standard radiation...

BACKGROUND AND PURPOSE Recent reports suggest that vascular factors play a crucial role in the development and progression of Alzheimer's disease. We aimed to assess vasomotor reactivity in patients with Alzheimer's disease and vascular dementia due to microangiopathy using transcranial Doppler sonography and near-infrared spectroscopy during a CO(2) exposition task. METHODS The normalized CO...