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PubMed1996

Modulating factors of individual sensitivity to diepoxybutane: sister chromatid exchanges induced in vitro in human lymphocytes.

Spontaneous and diepoxybutane (DEB)-induced sister chromatid exchanges (SCEs) were examined in cultured peripheral lymphocytes (PBL) from 122 healthy donors. SCE-inducing activity under defined experimental conditions and individual sensitivity to genotoxic stress were assessed. SCE means distribution appeared asymmetrical, identifying about 22% of subjects characterized by a 'high-respondent' phenotype with more than 111 SCEs/cell. Confounding factors, such as smoking habit, wine and coffee consumption, work activity and hematological factors, showed a limited capacity to affect individual SCE responsiveness, however hemoglobin and uric acid seemed to antagonize DEB genotoxicity.

Adult↗
PubMedDate not supplied

Tired blood. Part 2.

Anemia, "tired blood," with all the accompanying symptoms, such as fatigue, dyspnea, dizziness, muscle weakness, altered brain function, decreased gastrointestinal function, and cardiac stress, is not a disease. Rather, anemia is a sign that something has interfered with the red blood cell transport system that carries hemoglobin-containing oxygen to all bodily tissues (National Anemia Action Council [NAAC], 2002). In part 1 of this discussion (May/June issue of Orthopaedic Nursing), anemias related to interference with red blood cell development were addressed. In this section, anemias related to hemoglobin abnormalities (microcytic hypochromic anemia) and anemias related to premature erythrocyte destruction (hemolytic anemia) are discussed. Treatment approaches and selected pharmacological interventions are identified.

Anemia, Hemolytic↗
PubMed1982

The absence of volume change in the gelation of hemoglobin-S.

The volume change for the gelation of deoxygenated sickle cell hemoglobin has been measured by dilatometry at 22.0 degrees C and found to be zero. The precision of the result is 0 +/- 1.4 ml/mol of protein present in the sample. When the solubility of the protein is taken into account, the precision is 0 +/- 5.1 ml/mol of gelled hemoglobin. The participation of "hydrophobic interactions" in sickle cell hemoglobin gelation and model compound studies of the volume change associated with transferring hydrophobic solutes from an aqueous to a hydrophobic milieu, as well as the volume changes of other globular protein polymerizations, led us, initially, to expect a large positive delta V. The results are discussed in the context of concentration effects in sickle cell hemoglobin solutions and of recent work on the pressure-induced denaturation of globular proteins, which also gives smaller volume effects than had been anticipated.

Chemical Phenomena↗
PubMedDate not supplied

Mixed Plasmodium falciparum-Plasmodium malariae infection and hemoglobin SC disease: a case report.

In today's society, immigration and travel has resulted in large-scale population movements. This poses an additional challenge to the clinician when he or she takes the patient's history. The differential diagnosis of any presentation would need to include any diseases endemic to the area where the patient had been in. Ghana is considered a holoendemic high-risk area for the transmission of malaria. Moreover, compound heterozygous inheritance of hemoglobin (Hb) S and HbC often occurs in this area. We present a case of mixed Plasmodium falciparum-Plasmodium malariae infection complicating HbSC disease in a 34-year-old Ghanaian immigrant. We postulate that the malaria infection has transformed the patient's silent combined hemoglobinopathies (HbS/HbC) into a syndrome resembling a sickle cell crisis.

Adult↗
PubMed2001

The absorption and metabolism of iron amino acid chelate.

This paper summarizes several studies which describe significant increases in the intestinal absorption of iron from iron amino acid chelate compared to inorganic iron salts. While these increased uptakes of iron from the amino acid chelate into mucosal tissue are highly significant, this paper also demonstrates that there is a mechanism in the mucosal tissue which controls the quantity of iron from the amino acid chelate that is transferred to the plasma. For example, the higher the hemoglobin value, the less iron transferred. When considered together these studies demonstrate that iron amino acid chelate is both a safe and effective source of iron for treatment of iron deficiencies.

Animals↗
PubMed1975

Iron supplementation in suckling rats: its effect on the heart.

The present study attempted to determine the significance of the "anemia" which normally occurs in infants. We compared various parameters in suckling rats whose hemoglobin concentration had been artificially raised by gastric tube feeding of iron with those of control animals. The 20-day-old experimental animals showed significant increases in the weights of the liver (10%) aan spleen (40%). They had also developed a statistically significant 8% increase in heart weight, accompanied by a smaller myocardial fiber size and, thus, higher fiber density. The association in these young animals of higher than normal hemoglobin levels with smaller hearts and myocardial fibers suggests that the normally developing "anemia" of infancy may well serve an important physiological function: to stimulate myocardial growth.

Anemia↗
PubMed1987

Differential loss of enzyme activity by vitC and iron containing proteins.

Our earlier studies showed that rabbit muscle phosphoglucomutase was irreversibly inactivated by exposure to a mixture of vitamin C, FeCl3 and O2. The enzyme lost about 70% of its phosphate (V.V. Desphande and J.G. Joshi, J. Biol. Chem. 260, 754-764, 1985). The present report shows that several other iron proteins can substitute for FeCl3 to a varying degree. The rate of inactivation by FeCl3 greater than ferritin greater than hemoglobin = hemerythrin greater than transferrin = ferridoxin = vitamin C. These iron compounds also produced dephosphoenzyme but did not dephosphorylate ATP, ADP, AMP or phospholipids.

Animals↗
PubMedDate not supplied

Techniques for studying stimulation of fetal hemoglobin production in human erythroid cultures.

This report describes in detail the procedures for growing human erythroid cells in liquid culture for evaluating the potential of pharmacological agents to affect hemoglobin production. The procedure consists of two phases: an erythropoietin-independent phase in which peripheral blood mononuclear cells are first cultured in the presence of a combination of hemopoietic growth factors, but in the absence of erythropoietin, where early erythroid committed progenitors proliferate and differentiate into more mature progenitors. In the second phase, the latter cells, cultured in an erythropoietin-supplemented medium, continue to proliferate and mature into orthochromatic normoblasts and enucleated erythrocytes. This procedure produces large cultures of relatively pure and synchronized erythroid cell populations derived from normal donors or patients with beta hemoglobinopathies. The cultured cells recapitulate many aspects of erythropoiesis in vivo, including the donor's pattern of hemoglobin production (types and proportions). Tested compounds, at different concentrations, are added at different stages of the culture. The various types of hemoglobins and globin chains produced can be measured by high performance liquid chromatographic techniques and their cellular distribution analyzed by flow cytometry using fluorescently labeled antibodies against specific hemoglobins. This approach provides a screening system for compounds with potential therapeutic efficacy in patients with beta hemoglobinopathies.

Benzidines↗
PubMed2000

Orally administrated cerium chloride induces the conformational changes of rat hemoglobin, the hydrolysis of 2,3-DPG and the oxidation of heme-Fe(II), leading to changes of oxygen affinity.

The structure and oxygen affinity of hemoglobin from erythrocytes of CeCl(3) fed Wistar rats in the dose range of 0.2-20.0 mg/kg body weight/day were investigated by means of various spectroscopic methods. The changes in oxygen saturation curves of hemoglobin are dependent upon both feeding dose and feeding time. After 40 days feeding with 20 mg CeCl(3)/kg body weight/day, the curve changed to a double sigmoid shape and the oxygen affinity in low oxygen pressure increases. It regained the sigmoid form after 80 days feeding, but the degree of oxygen saturation in higher oxygen pressure became higher than that in the control. These results indicate that CeCl(3) can increase the oxygen affinity of hemoglobin of rat erythrocytes. This effect is further demonstrated by the analysis of Mössbauer spectra of erythrocytes. Increase of hemoglobin content in erythrocytes was found in rats fed with CeCl(3). It might be the offset response to the poor oxygen-releasing capability of the hemoglobin. CD and FT-IR deconvoluted spectra indicate that secondary structures of hemoglobin have remarkable changes, characterized by a gradual decrease of alpha-helix content, in a dose- and feeding time-dependent fashion. Meanwhile, the 31P NMR spectra demonstrate that the level of 2,3-diphosphoglyceric acid (2,3-DPG) in erythrocytes, an allosteric regulator of oxygen release from hemoglobin, decreases due to its hydrolysis. In addition, the Mössbauer and ESR spectra show clearly that a fraction of the heme-iron changes from Fe (II) to Fe (III) in CeCl(3) fed rats. The results indicate that the oral administration of CeCl(3) leads to a microenvironment changes of heme in intracellular hemoglobin. Oxygen affinity changes might be attributed to a series of events triggered by the binding of Ce (III) to hemoglobin and 2,3-DPG, including conformational changes of hemoglobin and 2,3-DPG hydrolysis, respectively and also the partial transformation from heme-Fe (II) to heme-Fe (III).

2,3-Diphosphoglycerate↗
PubMed1997

Structure and stability of human hemoglobin microparticles prepared with a double emulsion technique.

Hemoglobin solutions can be used as blood substitutes but they present some disadvantages often due to their rapid removal from the bloodstream after injection. A possible way of overcoming this problem is to trap hemoglobin inside particles. This study deals with the preparation, structure and stability of poly(lactic acid) and ethylcellulose microparticles containing human hemoglobin obtained with a double emulsion technique. We investigated the manufacturing process of these particles in order to increase the encapsulation ratio of hemoglobin. For this purpose, some parameters involved in the procedure were optimized, such as hemoglobin concentration and duration of stirring: hemoglobin loading increases with its concentration in the preparation and well-defined stirring time avoids a leakage of hemoglobin. Hemoglobin concentration, surfactant concentration i.e. poly(vinylic alcohol), amounts of polymer and solvent (methylene chloride), duration and speed of stirring. The microparticles were prepared with satisfactory yields (60 to 73%). They were spherical and their mean size was lower than 200 microns. The functional properties of entrapped hemoglobin were studied. The encapsulation did not alter hemoglobin and the oxygen affinity of the hemoglobin remained unmodified (P50 about 13.9 mm Hg in a Bis-Tris buffer pH 7.4 at 37 degrees C). Moreover, only low levels of methemoglobin could be detected (less than 3%). Besides, about 90% of encapsulated hemoglobin could be released from microparticles, with a speed related to the internal structure of the particles. The prepared microparticles were stored during one month at +4 degrees C. No degradation of the particle structure occurred and the functional properties of hemoglobin were preserved. These particles could provide a potential source of oxygen in the field of biotechnologies but any application for a transfusional purpose would first require a drastic reduction in particle size.

Drug Compounding↗
PubMed1982

Rapid method for eliminating labile glycosylated hemoglobin from the assay for hemoglobin A1.

The irreversible formation of stable glycosylated hemoglobin proceeds through a labile intermediate that is indistinguishable, by most methods, from the stable glycosylated product. The inclusion of the labile intermediate, which changes acutely with acute blood glucose changes, detracts from the utility of the assay as an index of chronic glucose concentration. We have developed a rapid, reliable chemical method for eliminating the labile intermediate: a 30-min incubation of whole-blood samples with semi-carbazide (30 mmol/L) and aniline (12 mmol/L) at pH 5 and 38 degrees C. The semicarbazide serves as a glucose trap; the transfer of glucose from the labile glycosylated hemoglobin to the semicarbazide is catalyzed by the acidic pH and aniline. This treatment is effective in the three most commonly used assays: "high-performance" liquid chromatography, electrophoresis, and a minicolumn kit.

Aniline Compounds↗
PubMed1993

Augmentation by erythropoietin of the fetal-hemoglobin response to hydroxyurea in sickle cell disease.

BACKGROUND: Hydroxyurea increases the production of fetal hemoglobin in patients with sickle cell anemia, inhibiting the polymerization of hemoglobin S and potentially improving vaso-occlusive manifestations and hemolysis. Recombinant erythropoietin increases the number of reticulocytes containing fetal hemoglobin in laboratory animals and in humans. We studied whether hydroxyurea and erythropoietin might have a potentiating effect on the production of fetal hemoglobin in patients with sickle cell disease. METHODS: We treated four patients who were receiving hydroxyurea for sickle cell disease (three who were homozygous for sickle cell anemia and one with sickle beta zero-thalassemia) with escalating doses of intravenous erythropoietin for seven weeks, along with oral iron sulfate. Doses of hydroxyurea on four consecutive days were alternated with doses of erythropoietin on three consecutive days. RESULTS: There was a 28 percent increase in the number of reticulocytes containing fetal hemoglobin and a 48 percent increase in the percentage of fetal hemoglobin, as compared with the maximal values obtained with hydroxyurea alone. The percentage of erythrocytes containing fetal hemoglobin (F cells) increased from 64 to 78 percent. As compared with hydroxyurea alone, treatment with hydroxyurea and erythropoietin decreased the mean (+/- SD) serum indirect bilirubin level from 0.8 +/- 0.2 to 0.5 +/- 0.1 mg per deciliter (13.3 +/- 2.9 to 8.9 +/- 2.2 mumol per liter) (P = 0.02), suggesting a further decrease in hemolysis. Red-cell filterability improved. CONCLUSIONS: Intravenous recombinant erythropoietin with iron supplementation alternating with hydroxyurea elevates fetal-hemoglobin and F-cell levels more than hydroxyurea alone. Such increases decrease intracellular polymerization of hemoglobin S and improve the overall rheologic characteristics of erythrocytes. A reduced dosage of hydroxyurea alternating with erythropoietin may prove less myelotoxic than hydroxyurea given daily or in pulsed-dose regimens. It may also increase levels of fetal hemoglobin in patients with sickle cell disease who have not been helped by hydroxyurea alone.

Adult↗
PubMed1995

A rheological equation to express the relations among hemoglobin contents, hematocrits, and viscosity of hemosome.

The relations among hemoglobin contents, hematocrit and viscosity of hemosome at a fixed shear rate have been studied. These relations can be well fitted by a rheological equation with internal viscosity of hemosome, (Tk)h, as a parameter. Where, (Tk)h are correlated (r = 0.996) with logarithm of hemoglobin content of hemosome by an equation: (Tk)h = 0.315 ln (hemoglobin contents of hemosome) + 0.435. The correlation can serve as an alternative way to predict hemoglobin content of hemosome instead of Benesch's method. The results of this study serve as a reference to determine an optimal conditions for in vivo tests of hemosome.

Animals↗
PubMed1977

Binding of CO to mutant alpha chains of hemoglobin M Iwate; evidence for distal imidazole ligation.

The optical contribution of the beta chains to the spectrum of hemoglobin M Iwate (alpha87his leads to tyr)2beta2a was subtracted with the aid of a computer so that the spectrum of ferric alpha chains was obtained. Tyrosinate binding to the heme is suggested from spectral resemblance to ferric heme phenolate in dimethyl sulfoxide. The slow reduction of the abnormal ferric alpha chains in hemoglobin M Iwate by dithionite was studied spectrophotometrically both in the presence and absence of CO. The rate of reduction was found to be dependent on the state of ligation of the normal beta chains. The CO-ligated form of the reduced alpha chains bears strong spectral resemblance to the CO-ligated form of the reduced beta chains suggesting similar structures for the heme-ligand complex. A model compound with similar optical properties to the CO-ligated protein can be prepared in dimethyl sulfoxide from hemin chloride, imidazole, and CO using chromous acetate as the heme reductant. Substitution of phenolate for imidazole produces a spectral entity so different from that observed in the protein as to rule out tyrosinate ligation to ferrous heme of the alpha chains when CO is bound.

Carbon Monoxide↗
PubMed1998

Effect of an allosteric modifier of hemoglobin, RSR-4, on oxygen affinity and oxygen saturation of hemoglobin in rabbits.

Theoretically, if the arterial partial oxygen pressure (PaO2) does not change, a right shift in the oxygen equilibrium curve (OEC) of hemoglobin should reduce arterial oxygen saturation. In this study we investigate whether a right shift in the OEC of hemoglobin decreases transcutaneous oxygen saturation (Tc-SO2) following the administration of an allosteric effector, 2-[4-(((3, 5-dichloroanilino)-carbonyl) methyl) phenoxy]-2-methylpropionic acid (RSR-4). The effect of RSR-4 on hemoglobin oxygen affinity was studied in four New Zealand white male rabbits. Following intraperitoneal administration of RSR-4, Tc-SO2 decreased in a dose-dependent manner. P50 (partial oxygen pressure at 50% hemoglobin oxygen saturation) in whole blood increased as the concentration of RSR-4 increased. Tc-SO2 decreased as whole-blood affinity (1/P50) decreased. There was no positive correlation between Tc-SO2 and PaO2. We concluded that a decrease in hemoglobin oxygen affinity following RSR-4 administration reduced arterial oxygen saturation. This decrease in the presence of an allosteric effector such as RSR-4 in vivo can be detected and monitored as a reduction in Tc-SO2.

Aniline Compounds↗