Despite the widespread use of radio frequency (RF) ablation, an effective way to assess thermal tissue damage during and after the procedure is still lacking. We present a method for monitoring RF ablation efficacy based on thermally induced methemoglobin as a marker for full tissue ablation. Diffuse reflectance (DR) spectra were measured from human blood samples during gradual heating of the s...

=> 7' 7 ,72 Recent studies of chronic hypercapnia in guinea pigs and rats demonstrated a biphasic shift in the blood oxygen dissociation curve, a diminution of heme-heme interaction and a significant decrease in the oxygen capacity of blood which was not due to decreased hemoglobin content. The latter finding suggested production of non-functional hemoglobin during hypercapnia. We measured the ...

The technique for freezing, drying, and preserving in vacuo which is in common use for plasma can be successfully applied to hemoglobin solutions when the hemoglobin is first deoxygenated to the extent of 99.7 per cent or more. In confirmation of Morrison and Hisey, the preliminary deoxygenation of the solution is found necessary to avoid formation of methemoglobin during drying. If a solution ...

The binding of p-hydroxymercuribenzoate to human methemoglobin causes a perturbation of the visible heme abosrption spectrum which is expressed by an increase in absorbance in the high spin band regions, 480 to 510 nm and 590 to 640 nm, concomitant with a decrease in absorbance in the alpha- and beta-band absorption regions. The pH dependence of the p-hydroxymercuribenzoate-induced difference s...

Several pathologic conditions are associated with hemolysis, i.e. release of ferrous (Fe(II)) hemoglobin from red blood cells. Oxidation of cell-free hemoglobin produces (Fe(III)) methemoglobin. More extensive oxidation produces (Fe(III)/Fe(IV) O) ferryl hemoglobin. Both cell-free methemoglobin and ferryl hemoglobin are thought to contribute to the pathogenesis of hemolytic disorders. We show h...

Y OUNG INFANTS are unusually susceptible to the development of methemoglobinemia upon exposure to certain medications and toxic agents. Ingestion of well water containing large quantities of nitrate will cause methemoglobinemia in small babies while older members of the family remain unaffected.14 Bismuth subnitrate, benzocaine, resorcin or aniline dye, taken by mouth or absorbed rectally or pe...

INTRODUCTION To evaluate the cause of methemoglobinemia in patients undergoing extended daily hemodialysis/hemodiafiltration we analyzed the relationship between methemoglobinemia and the water disinfection schedule of the hospital. METHODS We reviewed all arterial blood gas analyses, obtained over a one-year period, in patients undergoing extended hemodialysis/hemodiafiltration, and compared...