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PubMed2004

Effect of potassium dichromate and fenitrothion on hemoglobins of Chironomus riparius Mg. (Diptera, Chironomidae) larvae: potential biomarker of environmental monitoring.

In an attempt to identify Chironomus hemoglobins as biomarkers for environmental monitoring, alterations in the hemoglobins in Chironomus riparius Mg. (Diptera: Chironomidae) larvae, exposed to potassium dichromate and fenitrothion, were investigated under laboratory conditions. The hemoglobins were evaluated in terms of their total contents by a cyanomethemoglobin procedure, individual components by electrophoresis of isoelectric focusing, and their oxidation by multi wavelength rapid-scanning spectrophotometry. The total hemoglobin contents increased at the high level of fenitrothion exposure. No variations in the individual hemoglobin component levels were found, by exposure to either fenitrothion or potassium dichromate. Whereas, the absorption spectra of the hemoglobins showed decreases in the peaks corresponding to the oxyhemoglobins by exposure to both compounds, but more sensitively by the chromium, which probably reflects the increase of the autoxidation of the oxyhemoglobins to methemoglobins by these compounds. These results suggest that autoxidation of the hemoglobins in Chironomus riparius seems to be a sensitive parameter in response to redox-active chemical exposure, and this biochemical parameter could be developed as a biomarker in environmental monitoring.

Animals↗
PubMed2001

Bioavailability studies of a new iron source by means of the prophylactic-preventive method in rats.

The bioavailability of iron from a new commercial source containing ferric gluconate stabilized with glycine sold under the trade name Bioferrico was studied in this work by means of the prophylactic-preventive test in rats. NaFeEDTA was also studied by the same methodology for comparative purposes and ferrous sulfate was used as the reference standard. The test was conducted for 4 wk with male weaned rats, which were randomized into four groups of at least eight animals each. A control group received a basal diet of low-iron content, whereas the other groups received the same diet with iron added at a dose of 20 mg/kg as FeSO4.7H2O, NaFeEDTA, and Bioferrico, respectively. Individual hemoglobin concentrations (HbC) and weights were determined at the beginning and at the end of the study and food intake was daily registered. The iron bioavailability (BioFe) of each source was calculated as the ratio between the amount of iron incorporated into hemoglobin during the treatment (HbFe) and the total iron intake per animal (ToFeIn). A relative biological value (RBV) was obtained for each iron source under study as the ratio between the BioFe of the tested compound and that of the reference standard. The RBVs were 98% and 86% for Bioferrico and NaFeEDTA, respectively. Bioferrico showed a high bioavailability and behaved inertly in relation to the sensorial properties of the fortified food when it was added to flour. These qualities emphasize Bioferrico as a promising source for iron fortification.

Animals↗
PubMed1995

Hemoglobin adducts for in vivo dose monitoring and cancer risk estimation.

For the estimation of cancer risks from environmental chemicals, knowledge of the target dose is essential, dose being defined as the time integral of concentration in target tissues. In vivo doses from chronic or intermittent exposures are best determined from established steady-state levels of macromolecule adducts of reactive compounds or intermediates. For dose monitoring, hemoglobin (Hb) is preferred to DNA for several reasons: accessibility in large amounts, availability of methods for chemical identification, and well-determined life span due to absence of repair. For these reasons, and because of the proportionality of rates of DNA and Hb adduct formation, Hb adduct levels give better information on cumulative DNA adduct levels than do direct measurement of DNA adducts. The scientific background of Hb adduct measurement, target dose determination, and risk estimation based on the relative genotoxic potency, with gamma-radiation as reference standard, is reviewed and exemplified. The sensitivity of the method for Hb adduct measurement permits determination of exposures where the associated annual cancer risk is less than 1 per million. Besides application for studies of metabolism by determination of in vivo doses in exposed animals and humans, as a basis for risk estimation, Hb adduct measurement is used for hygienic surveillance of occupational exposures. Determination of Hb adducts by mass-spectrometric techniques gives a tool for identification of reactive metabolites, not only in individuals with known exposure, but also for characterization of adducts to Hb from compounds acting as mutagens (initiators) in the background carcinogenesis. This is the large fraction of the total number of cancer cases that occur among individuals without known exposure.

Carcinogens↗
PubMed1990

Hemoglobin causes release of inositol trisphosphate from vascular smooth muscle.

To test the hypothesis that oxyhemoglobin causes contraction of vascular smooth muscle by production of inositol 1,4,5-trisphosphate which results in a release of intracellular calcium, smooth muscle cells were exposed to oxyhemoglobin and inositol trisphosphate was measured. Oxyhemoglobin, but not methemoglobin which has much less contractile action, stimulated inositol trisphosphate production. The time course was consistent with an early role for this compound in the contraction produced by hemoglobin. The increase in production of inositol trisphosphate was inhibited by pertussis toxin and also by neomycin, an inhibitor of phospholipase C, although the actions of the latter compound cannot be attributed only to an inhibition of the enzyme responsible for the production of inositol trisphosphate.

Animals↗
PubMed1979

Oxygen binding of fetal and adult bovine hemoglobin in the presence of organic phosphates and uric acid riboside.

The P50 values of "stripped" fetal and adult bovine hemoglobin were 18.4 and 28.9 respectively. Neither the oxygen-hemoglobin dissociation curve nor the Hill coefficient, n, of fetal or adult bovine hemoglobin was affected by uric acid riboside (UAR), 2,3-diphosphoglyceric acid (2,3-DPG), adenosine triphosphate (ATP), or inositol pentaphosphate (IPP). Combinations of UAR and ATP with adult bovine hemoglobin or 2,3-DPG and ATP with fetal hemoglobin also had no effect. It was concluded that neither adult nor fetal bovine red cells contained an identifiable compound which affects the binding of oxygen to hemoglobin.

Adenosine Triphosphate↗
PubMed2001

Cross-linked hemoglobin as a potential membrane for an artificial red blood cell.

A cross-linked hemoglobin membrane has been created with discerning permeability between dissolved hemoglobin and small molecules. Such a membrane could be used to enclose a sphere of hemoglobin solution thereby allowing the entire "cell" to transport oxygen. The hemoglobin membrane was cross-linked on a polycarbonate support; the mechanical support was necessary for diffusion experiments in this study and would not be used during any sphere preparation. A 30% methemoglobin solution in phosphate buffer was used to fill the pores of the 10 microm polycarbonate support, then cross-linked with a homobifunctional cross-linking agent. The cross-linked hemoglobin within the support was evaluated for hemoglobin and benzoic acid permeability in a side-by-side diffusion cell. Disuccinimidyl glutarate, disuccinimidyl suberate and disuccinimidyl tartrate were used as cross-linking agents. Disuccinimidyl glutarate, 4.65 mM, created a hemoglobin-impermeable membrane after cross-linking for 20 minutes, reducing the concentration to 0.46 mM required a cross-linking time to 60 minutes. Benzoic acid, representing a typical small molecule, was capable of diffusing through the disuccinimidyl glutarate cross-linked hemoglobin membrane at 87.2% of its diffusion through buffer.

Animals↗
PubMed1997

Fetal erythropoiesis and the diagnosis and treatment of hemoglobin disorders in the fetus and child.

Although synthesis of adult hemoglobin (alpha 2 beta 2) is reduced or absent in both alpha and beta thalassemias, these disorders differ in their clinical significance to the fetus and neonate. alpha-Globin synthesis is observed in the yolk sac by 3 weeks of gestation and, by 9 weeks of gestation, alpha-globin represents the main alpha-like hemoglobin in the fetus. By contrast, the switch to beta-globin chain synthesis usually remains incomplete until 1 year after birth. Therefore, the clinical manifestations of homozygous beta-thalassemia may be ameliorated by sustained synthesis of fetal hemoglobin during the first 6 months of life, whereas up until 10 years ago, homozygous alpha-thalassemia was invariably associated with death in utero. More recently, reports of infants with homozygous alpha-thalassemia surviving the neonatal period have emerged, observations particularly relevant to large numbers of immigrants to North America from Southeast Asia, where alpha-thalassemia is common. Studies of patients with the beta-globin disorders thalassemia and sickle cell disease showed that the severity of both disorders is ameliorated by sustained synthesis of fetal hemoglobin into adult life. Hence, treatment for both these disorders has focused on the pharmacological manipulation of fetal hemoglobin. Studies in vitro, in animal models, and in affected patients have shown that several compounds stimulate gamma-globin synthesis and fetal hemoglobin production through a variety of proposed mechanisms. Some of the successes in human trials are outlined herein.

Antisickling Agents↗
PubMed1984

[Characteristics of the chemiluminescence of the system containing H202 in the presence of iron compounds].

The relative effectiveness of radical formation by different concentrations of hemoglobin, hemin and Fe2+ in the reaction with H2O2 evaluated by the intensity of chemiluminescence was studied. Hemoglobin was shown to be remarkably effective at the concentrations close to those in blood plasma. It is suggested that exoerythrocyte hemoglobin and the products of its destruction up to hemin are the most effective prooxidants and potential centers of radical formation in the blood.

Ferrous Compounds↗
PubMed1989

Induction of severe tumor hypoxia by modifiers of the oxygen affinity of hemoglobin.

Methods have been compared for inducing severe hypoxia in experimental tumors. Hypoxic fractions in the tumors were obtained from measurements of the displacement of cellular survival plots in vitro following tumor irradiation in vivo. Two compounds that displace to the left, oxygen-hemoglobin association curves greatly increase the hypoxic fractions in the tumors. The compound BW12C increases the hypoxic fractions in the KHT and Lewis-Lung tumors from about 10% to between 50-100%. The longer acting analogue BW589C increases hypoxic fraction in the KHT tumor to the same level achievable by treatment with the vaso-active drug hydralazine. The effect is also observed in the RIF-1 tumor even though the hypoxic fraction in this tumor is normally only about 1-3%. The kinetics for hypoxia induction by BW589C and its subsequent return to normal levels are comparable to those for the left-shifting of the oxy-hemoglobin association curve observable up to about 2 days post treatment.

Aldehydes↗
PubMed2006

Hydrogen-bonding conformations of tyrosine B10 tailor the hemeprotein reactivity of ferryl species.

Ferryl compounds [Fe(IV)=O] in living organisms play an essential role in the radical catalytic cycle and degradation processes of hemeproteins. We studied the reactions between H2O2 and hemoglobin II (HbII) (GlnE7, TyrB10, PheCD1, PheE11), recombinant hemoglobin I (HbI) (GlnE7, PheB10, PheCD1, PheE11), and the HbI PheB10Tyr mutant of L. pectinata. We found that the tyrosine residue in the B10 position tailors, in two very distinct ways, the reactivity of the ferryl species, compounds I and II. First, increasing the reaction pH from 4.86 to 7.50, and then to 11.2, caused the the second-order rate constant for HbII to decrease from 141.60 to 77.78 M-1 s-1, and to 2.96 M-1 s-1, respectively. This pH dependence is associated with the disruption of the heme-tyrosine (603 nm) protein moiety, which controls the access of the H2O2 to the hemeprotein active center, thus regulating the formation of the ferryl species. Second, the presence of compound I was evident in the UV-vis spectra (648-nm band) in the reactions of HbI and recombinant HbI with H2O2, This band, however, is completely absent in the analogous reaction with HbII and the HbI PheB10Tyr mutant. Therefore, the existence of a hydrogen-bonding network between the heme pocket amino acids (i.e., TyrB10) and the ferryl compound I created a path much faster than 3.0x10(-2) s-1 for the decay of compound I to compound II. Furthermore, the decay of the heme ferryl compound I to compound II was independent of the proximal HisF8 trans-ligand strength. Thus, the pH dependence of the heme-tyrosine moiety complex determined the overall reaction rate of the oxidative reaction limiting the interaction with H2O2 at neutral pH. The hydrogen-bonding strength between the TyrB10 and the heme ferryl species suggests the presence of a cycle where the ferryl consumption by the ferric heme increases significantly the pseudoperoxidase activity of these hemeproteins.

Ferric Compounds↗
PubMed1993

Relationship between environmental tobacco smoke exposure and carcinogen-hemoglobin adduct levels in nonsmokers.

BACKGROUND: A potent bladder carcinogen for workers in the dye industry, 4-aminobiphenyl (4-ABP), is present in environmental tobacco smoke and has been shown to bond covalently with hemoglobin. PURPOSE: The goal of this study was to examine the relationship between exposure to environmental tobacco smoke and levels of 4-ABP-hemoglobin adducts in nonsmoking pregnant women and to compare adduct levels in those women with levels in smoking pregnant women. METHODS: A questionnaire on smoking and exposure to environmental tobacco smoke was administered to 15 pregnant women who smoked cigarettes and 40 who did not smoke. Exposure was quantified for 1 week with a personal diary and by air sampling with a monitor worn by each woman. The monitor collected nicotine by passive diffusion to a filter treated with sodium bisulfate, and the deposit on the filter was analyzed by gas chromatography. Aliquots of maternal blood and cord blood collected during delivery were analyzed for 4-ABP-hemoglobin adducts by gas chromatography with negative ion chemical ionization mass spectrometry. RESULTS: The mean adduct level in smokers (184 pg of 4-ABP per gram of hemoglobin) was substantially higher than that in nonsmokers (22 pg/g). This difference was statistically significant. Among nonsmokers, the levels of 4-ABP adducts increased significantly with increasing environmental tobacco smoke level (P = .009). Those in the lowest exposure category (< 0.5 micrograms/m3 weekly average nicotine) had median 4-ABP-hemoglobin adduct levels of 15 pg of 4-ABP per gram of hemoglobin, while those in the highest exposure category (> or = 2.0 micrograms/m3) had median levels of 26 pg/g. Nonsmokers in this study had a median adduct level of 20 pg/g, and smokers had a median level of 143 pg/g. CONCLUSIONS: 4-ABP-hemoglobin adduct levels in nonsmokers were 14% of the levels in smokers, which is consistent with findings of 20% in two other studies. Nonsmokers may receive a nontrivial dose of carcinogens from environmental tobacco smoke proportional to their exposure to environmental tobacco smoke. IMPLICATION: The relationship between environmental tobacco smoke exposure and 4-ABP-hemoglobin adduct levels supports epidemiologic evidence that environmental tobacco smoke is carcinogenic to passive smokers.

Aminobiphenyl Compounds↗
PubMed2002

[Preparation, analysis and anti-anemic action of peroral powders with ferrous oxalate. Ferosol. 2].

Experiments with piglets showed good assimilation and metabolism of iron (II) in antianaemic powder Ferosol-1. In order to improve this drug, manganese, calcium (Ferosol-2, 1 composition) and ascorbic acid (Ferosol-2, 2 composition) were added. Manganese and ascorbic acid stimulate erythropoiesis and being strong reductants stabilize iron (II) on storage and in gastrointestinal tract. Components of Ferosol-2 were identified using colour, precipitation- and extraction tests, as well as paper chromatography and absorption spectroscopy. Quantitative analysis of microelements and ascorbic acid was performed using absorption spectroscopy, extraction photometry and iodometric titration methods. Ferosol-2 proved to be more stable than Ferosol-1. Lichfield and Wilkinson method modificated by Roth was used for detection of acute toxicity of Ferosol-2. A local action was estimated on quine pigs. Iron resorption was on 20 days old piglets. Antianaemic effectiveness of Ferosol-2 was evaluated on newborn piglets watching their weight. Experiments with white mice showed low toxicity of Ferosol-2 (LD50 = 4.3 g/kg, for 1 composition and 4.6 g/kg for 2 composition). It does not irritate mucosa of duodenum and ventriculus. Iron in Ferosol-2 was found to be well assimilated in gastrointestinal tract of piglets, easily gets into blood and joins albumen of plasma. After administration of Ferosol-2 to piglets increased iron concentration in blood serum was observed for 3 hours (1 composition) and 6 hours (2 composition). Experimental data showed increased resorption of iron in Ferosol-2, 2 composition due to ascorbic acid. Components of Ferosol-2 are well assimilated and join erythropoetic processes. Ferosol-2 leads to quicker weight gain as well as significantly higher amount of hemoglobin and red blood cells in piglets.

Administration, Oral↗