methemoglobin

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methemoglobin

[met‚hē·mə′glō·bən]
(biochemistry)
References in periodicals archive ?
MetHb is normally formed in small quantities and is rapidly destroyed by the NADH-MetHb reductase (cytochrome b5 reductase) enzyme in the erythrocytes, however, congenital methemoglobinemia patients have a deficiency of this enzyme.
An increase in MetHb concentration, which is normally less than 1% and has no oxygen-carrying ability, shifts the oxyhemoglobin curve to the left and may cause tissue hypoxia, lactic acidosis, and death in severe cases.
W badaniach eksperymentalnych wsrod ochotnikow jako szczyt stezenia MetHb po doustnym przyjeciu 65 mg aniliny okreslono ok.
Inhibition of peroxidase activity was assessed by combining the RBC lysate (reported in cellular equivalents/ml), metHb (0.5 mg/ml), or myoglobin (0.5 mg/ml) with increasing concentrations of PIC1, with a constant final volume, for 5 minutes before adding TMB as described below.
LPS can oxidize Hb and convert metHb, which facilitates iron release and generation of free radicles, a condition known to contribute to Hb related antibacterial activity.
Statistical analysis showed that there was significant difference (P less than 0.05) in the mean values of MetHb of group B as compared to group A and C but there was no significant difference (P greater than 0.05) in the mean values of MetHb of group A and C at day 20 and 30.
Medical charts of all infants with methemoglo-binemia were reviewed for birth weight (g), gender, postnatal age, Hb levels, presenting symptoms, etiologic causes, type of feeding, MetHb levels, treatment, recovery time of methemoglobinemia, and glucose-6-phosphate dehydrogenase (G6PD) deficiency.
The Fe3+/Fe2+ ratio was determined by the method of Davidson and Henry as modified by Uwakwe (2008), while the oxygen affinity of hemoglobin (Hb) and methemoglobin (metHb) measured 540 nm and 630 nm respectively using a Perkin Elmer lambda 2 spectrophotometer.
In methemoglobinemia, the concentration of metHb in the blood exceeds 1.5 g/dL (8%-12% of the normal Hb level), impairing oxygen transport and causing "anemic hypoxia." The regulatory enzyme NADH-cytochrome b5 reductase keeps Hb in an oxidized state.
Arterial blood gas analysis revealed; pH, 7.403; PC02, 30.9 mmHg; P02, 31.1 mmHg; S02, 54.9%; HC03, 18.9 mmol/L; MetHb, 0.9 %.
The compact GEM Premier 4000 analyzer provides blood-gas, electrolyte, metabolites, and CO-Oximetry measurements (e.g., Glu, Lac, Hct, tHb, [O.sub.2]Hb, COHb, HHb, MetHb) to allow consistent, accurate results throughout the hospital, at the point of care, and in the lab.