The interaction of human methemoglobin with inositol hexaphosphate (IHP) was examined by proton NMR spectroscopy. Upon addition of IHP, new proton peaks which are distinguishable from those observed in the absence of IHP appeared irrespective of the spin state of the ferric heme iron. the IHP-induced NMR peaks of low spin azide methemoglobin were not observed when azide was titrated to stripped...

The presence of methemoglobin, more rarely sulfhemoglobin, in the blood of patients treated with sulfanilamide has been reported by many investigators (1 a-f). Evelyn and Malloy (2), using their photoelectric colorimeter, found both these pigments but felt they were not responsible for the " cyanosis." Wendel (3), using his visual spectroscopic method (4), found methemoglobin and (occasionally)...

A soluble erythrocyte cytochrome b5 was purified as the substrate of methemoglobin reductase and an electron carrier to methemoglobin. The isoelectric point of this protein was at pH 4.3, and E0' was -0.010 at pH 7.0.. The Km value of the enzyme for this protein was 1 x 10(-4) M, and the turnover number (k5) was 3.4 x 10(4) min-1, with NADH as an electron donor at pH 7.0. The optimum pH of the ...

We describe a sensitive, accurate automated method for the simultaneous measurement of methemoglobin and total hemoglobin in blood. The method can be used for either continuous in vivo monitoring or intermittent sampling at a rate of 20/h. Standardization procedures are described, in which human blood treated with sodium nitrite is used. Repeatability of methemoglobin and total hemoglobin measu...

Sir, A 23-year-old male was admitted in our emergency room 3 h after suicidal ingestion of about 50 ml of unknown insecticide. His medical and family histories were negative for hereditary disorders. The patient was feeling lethargic and headache. On examination, he had stable vital signs. The heart and lung sounds were normal on auscultation. The skin and nail beds were grayish colored that di...

The oxidation of N-hydroxylated compounds may result in production of nitrogen oxides, including nitric oxide (NO). Oxidation may be independent on NO-synthase. Production of nitrites and nitrates via NO from formaldoxime and glyceryl trinitrate was studied and compared. Superoxide ion, ions Fe2+ and Fe3+, methemoglobin and methemoglobin + NADPH + methylene blue, oxyhemoglobin and oxyhemoglobin...

The apparently spontaneous conversion of hemoglobin to methemoglobin is an occurrence that has been recognized ever since the discovery of the latter blood pigment (Hoppe-Seyler, 1864). Although certain bacteria can oxidize hemoglobin to methemoglobin, the alteration of hemoglobin observed by the chemist is probably rarely due to bacterial action. Indeed, this conversion can occur in the comple...

In this laboratory a study of the oxygen capacities of chemically modified hemoglobins has recently been undertaken. In connection with this work the reduction of methemoglobin under carefully controlled conditions offered itself as a problem, since the combination of a ferriheme with globin leads to methemoglobin. In view of this consideration and of the recent reports of Cox and Wendel (l), M...

The objective of this prospective study was to determine if a correlation could be established between the ground-level concentrations of sulfur dioxide and methemoglobin concentrations in pregnant women when a coal-powered thermoelectric power plant was in operation ("dirty" period) and when it was closed ("clean" period). The location of the power plant, Plomin 1, in Labin, Croatia, was taken...

A review of the literature indicated an association among high nitrate ingestion, methemoglobinemia, and pathologic changes in bronchi and lung parenchyma. The present study examined a possible correlation among drinking water nitrate concentration, methemoglobin levels, cytochrome b(5) reductase activity, and acute respiratory tract infection with a history of recurrence (RRTI). Our study was ...