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PubMed2001

A novel approach for identification and measurement of hemoglobin adducts with 1,2,3,4-diepoxybutane by liquid chromatography/electrospray ionisation mass spectrometry and matrix-assisted laser desorption/ionisation tandem mass spectrometry.

The structural characterisation of the adducts formed by in vitro interaction of hemoglobin (Hb) with 1,2,3,4-diepoxybutane (DEB), the most reactive 1,3-butadiene (BD) metabolite, was obtained by liquid chromatography/electrospray ionisation mass spectrometry (LC/ES-MS) analysis of modified tryptic peptides of human hemoglobin chains. The reactive sites of human hemoglobin towards DEB and its hydroxylated derivatives (trihydroxybutyl (THB)-derivatives) were identified through the characterisation of alkylated tryptic peptides by matrix-assisted laser desorption/ionisation tandem mass spectrometry (MALDI-MS/MS). Based on this characterisation, a procedure was set up to measure the Hb-adducts of THB-derivatives by isotope dilution mass spectrometry with the use of a deuterated peptide standard. The results obtained here could permit optimisation of molecular dosimetry of BD-adducts, and extension of the analysis to the biological monitoring of occupational exposure to butadiene.

Alkylation↗
PubMed2005

An amperometric hydrogen peroxide sensor based on immobilization of hemoglobin in poly(o-aminophenol) film at iron-cobalt hexacyanoferrate-modified gold electrode.

A series of hybrid iron-cobalt hexacyanoferrate (FeCoHCF) films were electrodeposited on gold electrodes from solutions containing 6mM Fe(CN)(6)(3-) with different concentrations of Co(2+) and Fe(3+). FeCoHCF films deposited from solutions with different molar ratios of iron were studied by cyclic voltammetry, and their solid states were characterized by Fourier transform infrared spectroscopy. The kind of FeCoHCF film that deposited from a solution with a molar ratio of iron of 0.4 showed the largest response current to H(2)O(2) and was characterized by energy-dispersive X-ray spectroscopy. Therefore, the optimized FeCoHCF film was combined with nonconducting poly(o-aminophenol) (POAP) film that entrapped the hemoglobin (Hb) to construct hydrogen peroxide biosensor. The response current of the Hb/POAP/FeCoHCF/Au electrode (29.8 nA) was nearly 40 and was 1.5 times that of the Hb/POAP/Au (0.7 nA) and POAP/FeCoHCF/Au (20 nA) electrodes, respectively. The Michaelis-Menten constant of Hb in the Hb/POAP/FeCoHCF/Au film was 9.31 mM. These results show that the immobilized Hb in the Hb/POAP/FeCoHCF/Au film exhibits higher catalytic activity and larger response current to H(2)O(2) by the mediation of FeCoHCF. In addition, effects of applied potential, solution pH, and electroactive interferent on the response current of the Hb/POAP/FeCoHCF/Au electrode were investigated in detail.

Aminophenols↗
PubMed2002

Transgenic rice is a source of iron for iron-depleted rats.

Iron deficiency is one of the most prevalent nutrient deficiencies in the world. A sustainable solution to dietary iron deficiency may be achieved in part by increasing bioavailable iron in seeds used for foods such as rice. Because ferritin is used as a natural source of iron in the early development of humans, other animals and plants, the bioavailability of iron in rice seeds, provided in amounts equal to ferrous sulfate, and in transgenic rice with ferritin was tested in iron-deficient rats. A standard hemoglobin (Hb) repletion bioassay was used with rats made anemic followed by complete diets containing equivalent amounts of iron as FeSO(4) or one of three different bioengineered rice varieties (Kitaake and two transgenic derivatives with ferritin targeted to the seed, FK11 and FK22). Rice diets were as effective as the FeSO(4) diet in replenishing hematocrit, Hb concentration and liver iron concentrations. These data suggest that Mendelian and biotechnological approaches to manipulating ferritin expression of seed iron in rice may contribute to a sustainable solution to global problems of iron deficiency.

Anemia, Iron-Deficiency↗
PubMed2001

Treatment of anemia with microencapsulated ferrous fumarate plus ascorbic acid supplied as sprinkles to complementary (weaning) foods.

BACKGROUND: Standard therapy for anemia in infants is ferrous sulfate drops administered 3 times/d. Adherence to treatment, however, is often poor. One likely reason for poor adherence is the unpleasant side effects associated with drops. OBJECTIVE: The objective was to evaluate the use of a new form of iron and a delivery system to treat anemia in infants that is likely to produce better adherence to treatment. DESIGN: Using a prospective, randomized, controlled design, we studied 557 anemic children aged 6-18 mo (hemoglobin: 70-99 g/L) in rural Ghana. One group received a daily sachet of microencapsulated ferrous fumarate (80 mg elemental Fe) in powder form plus ascorbic acid to be sprinkled onto any complementary food eaten (sprinkles group); a control group received ferrous sulfate drops 3 times/d for 2 mo (total dose: 40 mg elemental Fe). Hemoglobin and serum ferritin concentrations were measured at baseline and at the end of treatment. RESULTS: Successful treatment of anemia (hemoglobin > 100 g/L) occurred in 58% of the sprinkles group and in 56% of the drops group, with minimal side effects in both groups. Geometric mean ferritin concentrations increased significantly in each group from baseline to the end of treatment (P < 0.001). CONCLUSION: Use of ferrous sulfate drops or a single daily dose of microencapsulated ferrous fumarate sprinkles plus ascorbic acid resulted in a similar rate of successful treatment of anemia without side effects. To our knowledge, this is the first demonstration of the use of microencapsulated iron sprinkles to treat anemia. Improved ease of use may favor the use of sprinkles to deliver iron.

Anemia, Iron-Deficiency↗
PubMed1977

Free erythrocyte porphyrin: hemoglobin ratios, serum ferritin, and transferrin saturation levels during treatment of infants with iron-deficiency anemia.

Free erythrocyte porphyrin:hemoglobin (FEP:Hb) ratios were determined on 20 infants with iron-deficiency anemia. FEB:Hb ratios were compared with simultaneously drawn serum ferritin and serum transferrin saturation levels. FEP:Hb ratios dropped steadily during treatment of the anemic infants, but remained elevated compared to age-matched nonanemic infants, until the anemia was corrected. FEP:Hb ratios detected iron deficiency when acute inflammatory disease was present. Serum ferritin levels and transferrin saturation failed to detect iron deficiency after iron therapy was started or when acute inflammatory disease was present. Measurement of FEP:Hb ratios is a reliable and practical way to make a prompt diagnosis of iron-deficiency anemia in infants.

Anemia, Hypochromic↗
PubMed2006

Hemoglobin niobate composite based biosensor for efficient determination of hydrogen peroxide in a broad pH range.

Inorganic layered niobates (HCa2Nb3O10) were used as immobilization matrices of hemoglobin (Hb) because of their tunable interlayer spaces, large surface areas and good biocompatibilities. A pair of well-defined, quasi-reversible cycle voltammertric peaks were obtained at the Hb-HCa2Nb3O10 modified pyrolytic graphite electrode, suggesting that the layered niobates facilitate the electron transfer between the proteins and the electrode. Hb-HCa2Nb3O10 modified electrode exhibited electrocatalytic response for monitoring H2O2 with a large linear detection range from 25 microM to 3.0 mM and a relatively high sensitivity of 172 microA mM-1 cm-2. Based on the stabilizing effect of the layered niobates, Hb-HCa2Nb3O10 modified electrode can detect H2O2 in strongly acidic and basic solutions with pH of 1-12, which greatly expands the application fields of biosensors.

Animals↗
PubMed1994

Fetal globin stimulation during a short-term trial of erythropoietin in HbS/beta-thalassemia patients.

Six sickle cell/beta-thalassemia patients (3 males and 3 females) were treated with 500 U/kg body weight human recombinant erythropoietin (h-rEPO) along with 300 mg/day iron sulfate in two phases, for a period of 90 days. Fetal hemoglobin (HbF) was assayed every 2 weeks and the gamma-chain ratio at three successive intervals during the treatment. All patients showed a moderate to high increase in their HbF values (1.25- to 12-fold). The gamma-chain ratio, as determined by high performance liquid chromatography was found to be unaffected by the HbF increase. Two patients with the newborn gamma-chain ratio, responded faster to the h-rEPO treatment and achieved higher HbF values than the rest of the group. The h-rEPO treatment was very well tolerated and had a positive effect on the general clinical condition of all the patients.

Adolescent↗
PubMed2004

Iron absorption and bioavailability in rats of micronized dispersible ferric pyrophosphate.

Unlike commercial ferric pyrophosphate, micronized dispersible ferric pyrophosphate (MDFP: Sun-Active Fe) does not precipitate and is completely dispersible in liquid form. MDFP shows a sharp particle size distribution at a nanometer level, which is several times smaller than that of commercial ferric pyrophosphate. The bioavailability of MDFP was compared to ferric pyrophosphate, sodium ferrous citrate, and ferrous sulfate by three bioavailability tests in rats; namely the serum iron concentration curve, the hemoglobin regeneration efficiency, and Association of Official Analytical Chemists' hemoglobin repletion test. The high area under curve value, a lag in peak time, and continued high serum iron concentration by MDFP over the other iron compounds indicates a sustained release of iron in the serum iron concentration curve method. MDFP showed the highest hemoglobin regeneration efficiency among all the iron compounds tested. The relative biological value of MDFP per unit of ferrous sulfate in each bioavailability test showed a high value as compared to other iron compounds. The above results suggest that MDFP is an ideal compound with high bioavailability for iron fortification in various liquid applications.

Analysis of Variance↗
PubMed1980

Differences in Fe(II)-N epsilon(His-F8) stretching frequencies between deoxyhemoglobins in the two alternative quaternary structures.

Resonance Raman spectra have been obtained of the alpha deoxy and beta deoxy subunits within valency hybrid hemoglobins both in the high-affinity (R) and low-affinity (T) structures. Upon conversion from the R to the T structure, the vibrational frequency of the Fe(II)-N epsilon(His-F8) bond changes from 223 to 207 or 203 cm-1 in the alpha deoxy subunit and from 224 to 220 or 217 cm-1 in the beta deoxy subunit. We estimate that the Fe(II)-N epsilon(His-F8) bond is stretched by the R leads to T transition 3 times more in the alpha subunit (0.024 A) than in the beta subunit (0.0085 A) and, accordingly, the strain energy developed in that bond is 8 times larger in the alpha than in the beta subunit. Hence, the oxygen affinity of the alpha and beta subunits may be regulated by different mechanisms.

Allosteric Regulation↗
PubMed1981

Reciprocal interactions between oxygen-binding and aquo-ferric chains in partially oxidized human hemoglobin A1.

The concomitant changes in oxygen binding by ferrous hemes and in oxygenation-linked difference in absorbance of ferric hemes at 630 nm were studied at pH 6.8 in human partially oxidized hemoglobin A (Hb++/+++). At concentrations of ferric hemes less than 20% no changes in P50 of oxygenation were noted in comparison to the P50 value of Hb A. An increase of ferric hemes from 20 to 80% resulted in a parallel increase in oxygen affinity of functional hemes. Prevalence of alpha chains among the oxidized chains was confirmed in the studied Hb++/+++ containing less than 20% of ferric hemes. The oxygenation linked increases in absorbance of ferric hemes at 630 nm were related in a linear fashion to the increase in the ferric hemes content fom 0 to 40%. The lack of change in oxygen affinity of HB++/+++ containing less than 20% of ferric hemes, which exhibits the oxygenation-linked changes in absorbance of ferric hemes may be related to the presence and properties of asymmetric tetramers alpha+++ alpha++ beta 2++.

Ferric Compounds↗
PubMed2004

[Iron replacement in hemodialysis patients with a normal serum ferritin level].

BACKGROUND AND OBJECTIVE: Iron deficiency limits the efficacy of recombinant human erythropoietin (rhEPO) therapy in end-stage renal disease patients. Therefore it is essential that serum ferritin levels should be maintened > 200 micro g/l. Functional iron deficiency occurs with serum ferritin levels > 200 micro g/l and transferrin saturation (TFS) lower than 20 %. The purpose of this study was to determine the efficacy of iron therapy in dialysis patients with serum ferritin levels higher than 200 micro g/l. PATIENTS AND METHODS: A total of 16 stable patients receiving chronic hemodialysis completed a 6-month survey period. Hemodialysis therapy and weekly subcutaneous rhEPO dose remained unchanged. Patients were divided into three groups according to their TFS, with TFS low (<20 %), barely adequate (20 % < TFS < 25 %) or optimal (>30 %). Sodium ferric gluconate complex (62.5 mg iron) was administered once per week intravenous over 10 minutes at the end of the dialysis. RESULTS: After 3 months, hemoglobin was significantly higher in all groups (10.3 +/- 0.7 g/dl to 12,6 +/- 1.3 g/dl; p < 0,01) with no difference between the three groups and was constant in the following 3 months. Intravenous iron therapy raised ferritin levels significantly after 3 and 6 months: this observation was similar in all groups. The rise in TFS varied between and within the three groups. CONCLUSION: Consistent intravenous iron therapy in combination with subcutaneous rhEPO had a rapid effect on the correction of anemia in patients with even optimal serum ferritin levels receiving chronic hemodialysis. There was no difference between patients with low, barely adequate and optimal TFS. It is concluded that there is a need for consistent intravenous iron therapy also in hemodialysis patients with optimal serum ferritin levels to correct anemia.

Aged↗
PubMed1993

[Hemoglobin C (alpha 2 beta 2 6Glu-->lys). Study of 19 heterozygote AC carriers and of 5 cases of double hemoglobinopathy SC].

This paper describes clinical findings in subjects heterozygous for hemoglobin C and in compound heterozygotes SC. Most of our patients were coming from lands bordering the Guinea Gulf, on the inside of the loop made by the river Niger and from Haiti, which was populated by African slaves coming mainly from the Golden Coast (actually Ghana). Heterozygotes are asymptomatic and do not suffer from anemia. Age at diagnosis is higher than for SCA, although one of our cases was diagnosed at age one. Overwhelming infections or major anemia were not observed. Basal hemolysis remained moderate. HbF levels were not increased as they may be in sickle cell anemia. Splenomegaly was observed in 2/5 patients. Among severe complications we encountered, we must mention one case of foetal death, one tibial infarct, one case of pure red cell aplasia caused by parvovirus B19 infection, and one case of proliferative retinopathy.

Adult↗
PubMed2002

Iron bis-glycine chelate competes for the nonheme-iron absorption pathway.

BACKGROUND: The enterocytic absorption pathway of the food fortificant iron bis-glycine chelate has been the subject of controversy because it is not clear whether that substance uses the classic nonheme-iron absorption pathway or a pathway similar to that of heme absorption. OBJECTIVE: The objective was to study the absorption pathway of iron bis-glycine chelate in human subjects. DESIGN: Eighty-five healthy adult women were selected to participate in 1 of 6 iron-absorption studies. Study A involved the measurement of the dose-response curve of the absorption of ferrous sulfate (through a nonheme-iron absorption pathway); study B involved the competition of iron bis-glycine chelate with ferrous sulfate for the nonheme-iron absorption pathway; study C involved the measurement of the dose-response curve of heme-iron absorption; study D involved the competition of iron bis-glycine chelate with hemoglobin for the heme-iron absorption pathway; and studies E and F were the same as studies A and B, except that the iron bis-glycine chelate was encapsulated in enteric gelatin capsules so that it would not be processed in the stomach. RESULTS: Iron from the bis-glycine chelate competed with ferrous sulfate for the nonheme-iron absorption pathway. Iron from the bis-glycine chelate also competed with ferrous sulfate for absorption when liberated directly into the intestinal lumen. Iron from the bis-glycine chelate did not compete with heme iron for the heme-iron absorption pathway. CONCLUSION: The iron from iron bis-glycine chelate delivered at the level of the stomach or duodenum becomes part of the nonheme-iron pool and is absorbed as such.

Absorption↗
PubMed1998

Bioavailability of iron in cottonseed meal, ferric sulfate, and two ferrous sulfate by-products of the galvanizing industry.

Iron depletion-repletion assays were carried out with young chicks to establish Fe bioavailability values for Fe2(SO4)3.7H2O (22.7% Fe), Fe-ZnSO4.H2O (20.2% Fe, 13.0% Zn), Zn-FeSO4.H2O (20.2% Zn, 14.2% Fe), and cottonseed meal (200 mg Fe/kg). Standard hemoglobin response curves were established using feed-grade FeSO4.H2O (28.8% Fe) or reagent-grade FeSO4.7H2O (20.1% Fe) as standards such that relative bioavailability (RBV) could be assessed for the experimental sources of Fe. Weight gain, hemoglobin, and hematocrit responded linearly (P < 0.05) to Fe supplementation in all assays. Using hemoglobin as the response criterion, slope-ratio calculations established Fe RBV values of 126% for Fe-ZnSO4.H2O and 93% for Zn-FeSO4.H2O. The 126% value for Fe-ZnSO4.H2O was greater (P < 0.05) than the FeSO4.H2O standard (100%), but the 93% value for Zn-FeSO4.H2O was not different (P > 0.10) from the standard. However, evaluation of all criteria of response (hemoglobin, hematocrit, weight gain) suggested that neither Fe-ZnSO4.H2O nor Zn-FeSO4.H2O had different Fe RBV values than FeSO4.H2O. Standard-curve calculations were used for assessment of Fe RBV in Fe2(SO4)3.7H2O and cottonseed meal, as only a single level of Fe addition was studied for each of these products. Iron RBV in Fe2(SO4)3.7H2O was estimated to be 37%, whereas Fe RBV in cottonseed meal was found to be 56%. Both of these values were lower (P < 0.05) than the FeSO4 standard. The data suggest that the two new products, representing combinations of FeSO4.H2O and ZnSO4.H2O by-products of the galvanizing industry, are excellent sources of bioavailable Fe, whereas ferric sulfate and cottonseed meal are relatively poor sources of usable Fe.

Animal Feed↗
PubMed1975

Heme reactivity of hemoglobins. Azide and fluoride binding equilibria of free and mercuriated ferri-gamma chains.

The free gamma chains, isolated from human foetal hemoglobin, are stable when oxidized and thus suitable for ligand binding and subunit equilibrium studies. The metaquo-ferri chains, with cysteine-F9 in the free state II ag gamma SH) possess several properties which are different from those of their p-mercuribenzoate derivative (III aq gammaSHgR); these are: stronger binding of a high-field ligand (N3- minus), altered spin equilibrium and an altered subunit equilibrium. A quantitative assessment of the free energy changes associated with all individual steps involved in changing the metaquo chains to their azide derivatives has been made. The results show that the higher apparent reactivity of III ag gammaSH (compared to IIIaq gammaSHgR) for the azide ion is not solely due to compensatory effects arising from differences of subunit dissociation or of spin equilibrium: other process(es) occurring in the ligand binding site have to be considered.

Azides↗
PubMed2003

New methods to evaluate endothelial function: Evaluation of endothelial function by hemoglobin-nitric oxide complex using electron paramagnetic resonance spectroscopy.

This minireview describes the practical use of assay systems to detect nitric oxide (NO) by electron paramagnetic resonance (EPR) spectroscopy for evaluation of endothelial functions. The iron(II)-dithiocarbamate complexes, such as iron(II)-(N-methyl-D-glucamine dithiocarbamate), are commonly used in EPR detection of NO both in vivo and in vitro. However, due to their redox activity, these complexes have some drawbacks that limit their usefulness for the detection of NO. On the other hand, the measurement of hemoglobin-NO adduct (HbNO) in whole blood by the EPR method seems relevant for the assessment of systemic NO levels. However, ceruloplasmin and an unknown radical species overlapping the same magnetic field as that of HbNO, which makes it physically impossible to measure small amounts of HbNO. Thus, to reveal the EPR spectrum of HbNO, we developed the EPR signal subtraction method, which is based on the computer-assisted subtraction of the digitized EPR spectrum of HbNO-depleted blood from that of the sample blood using software. Using this technique, we succeeded in measuring the steady blood HbNO level as an index of NO by the EPR HbNO signal subtraction method. We also demonstrated that temocapril reduces abnormalities of NO dynamics in the L-NAME (N(omega)-nitro-L-arginine-methylester)-induced endothelial dysfunction of rats using the EPR HbNO signal subtraction method.

Animals↗
PubMedDate not supplied

Construction of artificial methemoglobin reduction systems in Hb vesicles.

The hemoglobin vesicle (HbV) is a red cell substitute encapsulating purified concentrated Hb in a phospholipid vesicle. In order to suppress metHb formation for the long term maintenance of oxygen transporting capability in vivo, thiols (cysteine, Cys; homocysteine, Hcy) were studied as reductants of metHb. Hcy showed a suppressive effect on metHb formation, while Cys adversely accelerates metHb formation at the rate of twice the Hb solution without any reductants. The suppression of Cys-induced metHb formation by the addition of superoxide dismutase (SOD) and catalase indicated that Cys was easily oxidized by oxygen and simultaneously generated a large amount of active oxygens. The rate of metHb formation was influenced by PO2 and pH. Furthermore, the reducing systems (methylene blue (MB), NADH or ascorbic acid) were added to the outer aqueous phase of HbV, and the artificial reduction systems constructed through the bilayer membrane were evaluated.

Blood Substitutes↗