Sulphaemoglobin formation in fish: a comparison between the haemoglobin of the sulphide-sensitive rainbow trout (Oncorhynchus Mykiss) and of the sulphide-tolerant common carp (Cyprinus Carpio).
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A method for the quantitative determination of sulphaemoglobin (SHb) in a mixture of haemoglobin derivatives by spectral deconvolution is described. SHb formation was studied in haemolysates and in red blood cells of the sulphide-sensitive rainbow trout (Oncorhynchus mykiss) and of the sulphide-tolerant common carp (Cyprinus carpio). Addition of sulphide caused the formation of SHb in haemolysates of both animals. However, haemoglobin from common carp was much less sensitive to sulphide than was trout haemoglobin. The maximal obtainable SHb fraction was approximately 30 % in trout and 10 % in carp haemolysates. In both animals, the SHb fraction increased with increasing Hb and sulphide concentrations up to 100 micromol l(-)(1) and 1 mmol l(-)(1), respectively, and was favoured by a low pH. An increase of temperature between 5 and 25 degrees C strongly increased SHb formation in trout haemolysate. In contrast, temperature changes had almost no effect on SHb production in carp. Within trout red blood cells, approximately 7 % of total haemoglobin was converted to SHb during 60 min of incubation (with 2.5 mmol l(-)(1) sulphide), inducing a 20 % loss of haemoglobin oxygen-saturation. In carp red blood cells incubated under identical conditions, SHb formation was minimal and haemoglobin oxygen-saturation was not affected. (+info)
The origin of hydrogen sulfide in a newborn with sulfhaemoglobin induced cyanosis.
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This report investigated the origin of H(2)S in a newborn boy with sulfhaemoglobin induced cyanosis, who died because of multiple organ failure. Frozen material was collected and studied after death. The results suggest that enzymes had been released from deteriorating organs into the blood and abdominal fluid, and that the reaction of one of these enzymes with sulfur containing amino acids might have resulted in increased H(2)S concentrations. It is hypothesised that this release of enzymes resulted from a haemolysin produced by an invasive haemolytic Escherichia coli that was found in the blood and organs of this patient. (+info)
Structural determinants for the formation of sulfhemeprotein complexes.
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Pregnancy loss and maternal methemoglobin levels: an indirect explanation of the association of environmental toxics and their adverse effects on the mother and the fetus.
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Abnormal red cell metabolism in patients with chronic uremia: Nature of the defect and its persistence despite adequate hemodialysis.
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A red cell metabolic abnormality, which diminishes the maximum activity of the pentose phosphate shunt, occurs in some uremic patients, even those adequately dialyzed with fluids prepared from distilled or charcoal-filtered water. Within individual patients the severity of this abnormality does not change even after 9 mo of consecutive hemodialyses. However, between patients it does correlate inversely with hematocrit. When erythrocytes from patients with the abnormality are stressed with oxidant compounds, such as ascorbate, erythrocyte glucose consumption and lactate formation are abnormally increased, while lactate/pyruvate ratios abnormally diminish. Concomitantly, red cell glycolytic intermediates, including fructose-1,6-diphosphate, glyceraldehyde-3-phosphate, 3-phosphoglycerate, phosphoenol pyruvate, and pyruvate, markedly accumulate. Surprisingly, no increase of 2-phosphoglycerate occurs, which suggests that inefficient phosphoglyceromutase activity underlies this perturbation of erythrocyte metabolism and its associated hemolytic process. (+info)
Performance of an automated six-wavelength photometer (Radiometer OSM3) for routine measurement of hemoglobin derivatives.
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A new instrument for spectrophotometric determination of oxygen saturation (SO2) and the fractions of carboxyhemoglobin (FHbCO) and methemoglobin (FHi), the Hemoximeter OSM3 (Radiometer), was tested by comparative measurements with a multiwavelength method. We found that it gave reliable results for freshly drawn samples from patients. When samples with artificially induced high proportions of HbCO or Hi, or both, were introduced, results were still sufficiently accurate. The presence of sulfhemoglobin (SHb) seriously interfered with the measurement of SO2, FHbCO, and FHi, but the instrument reliably indicated its presence. Because SHb is rarely encountered, a reliable warning for its presence is adequate for clinical practice. Using the instrument in its fetal mode, we obtained accurate results for blood samples from newborns. (+info)
The reversible binding of oxygen to sulfhemoglobin.
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The O2 binding properties of sulfhemoglobin were studied. The oxygen tension required for half-saturation of sulfhemoglobin is more than 2 orders of magnitude higher than that for hemoglobin A. The binding of O2 exhibits an alkaline Bohr effect larger than that observed for hemoglobin, yet the Hill number is unity. From the Bohr titration curve, 0.68 proton is released during O2 binding at 0 degrees C. Sulfhemoglobin prepared from carboxypeptidase A-treated hemoglobin has an affinity for O2 which is about the same as that of sulfhemoglobin at the theoretical limit of the Bohr titration curve. Like its carboxypeptidase A-treated hemoglobin precursor, this sulfhemoglobin does not bind O2 cooperatively. Thus, sulfhemoglobin appears to be in a high affinity form at alkaline pH and a low affinity form at acid pH, similar to hemoglobin A. These results demonstrate that the magnitude of the Hill number is not always an indicator of the interaction between oxygen binding and other functions in a hemoglobin. (+info)