We report a new method for the quantitative determination of human methemoglobin (metHb) based on the measurement of the solvent-water proton-nuclear magnetic resonance (NMR) relaxation rate R1 [normalized to 1 mmol/L hemoglobin (Hb) concentration]. MetHb (%) is estimated from the linear dependence of R1 on the metHb concentration, taking into account the simple relationship [MetHb] = [(R1 - R1...

We hypothesize that combining quantitative near-infrared spectroscopy (NIRS) with established invasive techniques will enable advanced insights into renal hemodynamics and oxygenation in small animal models. We developed a NIRS technique to monitor absolute values of oxygenated and deoxygenated hemoglobin and of oxygen saturation of hemoglobin within the renal cortex of rats. This NIRS techniqu...

OBJECTIVE The relationship between paranoia symptoms and underlying prefrontal cortex mechanisms among healthy subjects was analyzed using near-infrared spectroscopy. METHODS Seventy-eight healthy subjects were assessed for paranoia symptoms using the Japanese version of the Paranoia Checklist. Changes in hemoglobin concentrations were assessed using 2-channel near-infrared spectroscopy on th...

Pulse oximetry measures the relative concentration of arterial oxygenated hemoglobin and reduced hemoglobin. This paper presents the design of a pulse oximeter, which measures the presence of a third substance, carboxyhemoglobin (HbCO), by unfiltered LEDs at 660 nm, 810 nm, and 940 nm. Background information is given on the theory of pulse oximetry. Theoretical approximations and calculations w...

The oxygen affinity of hemoglobin in K562 cells induced by hemin and the relationship between levels of 2,3-diphosphoglycerate (2,3-DPG) and hemoglobin have been investigated. Absorption spectra of induced cells indicate that the hemoglobin is oxygenated; oxygen dissociation curves are symmetric, with a P50 of 20 +/- 0.9 mm Hg, Hill coefficient of 2.5, and a normal temperature dependence. The i...

Over ninety years ago, on November 8, 1845, Michael Faraday investigated the magnetic properties of dried blood and made a note "Must try recent fluid blood." If he had determined the magnetic susceptibilities of arterial and venous blood, he would have found them to differ by a large amount (as much as twenty per cent for completely oxygenated and completely deoxygenated blood); this discovery...

The purpose of this study was to investigate the effect of stereoscopic display alignment errors on visual fatigue and prefrontal cortical tissue hemodynamic responses. We collected hemodynamic data and perceptual ratings of visual fatigue while participants performed visual display tasks on 8 ft × 6 ft NEC LT silver screen with NEC LT 245 DLP projectors. There was statistical significant diffe...