RESUMEN
Total reflection X-ray fluorescence analysis (TXRF) was used to determine chromium, selenium and bromine concentrations in blood serum samples of 50 patients with parenteral nutrition treatment. The concentrations were measured two times, namely in the first day (I measurement) of the treatment and the seventh day (II measurement) after the chromium and selenium supplementation. For comparison purposes also serum samples of 50 patients without nutritional disorders, admitted to a planned surgical procedure to remove the gall bladder (cholecystectomy), were analyzed and treated as the control group. Descriptive statistics of measured concentrations of Cr, Se and Br both for the studied and control groups was determined. In order to check the effectiveness of Cr and Se supplementation, the results of the first and seventh day measurements for studied group were statistically compared with each other, with literature reference values and with the results of the control group (two-group comparison). These comparisons indicate the effectiveness of selenium supplementation in the applied treatment procedure. In the case of Cr and Br concentrations no statistically significant differences were observed. We conclude that monitoring of the concentration of the important trace elements in human serum should be standard procedure in parenteral nutrition treatment. In this monitoring the TXRF technique can be successfully used.
Asunto(s)
Bromo/sangre , Cromo/sangre , Nutrición Parenteral , Selenio/sangre , Adulto , Anciano , Anciano de 80 o más Años , Bromo/normas , Estudios de Casos y Controles , Cromo/normas , Femenino , Humanos , Masculino , Persona de Mediana Edad , Valores de Referencia , Selenio/normas , Espectrometría por Rayos X/normasRESUMEN
RATIONALE: Accurate quantitative analysis of bromine and iodine in serum is an important aspect of monitoring body condition, but the volatile loss of halogen in sample pretreatment is a troublesome problem. We present a validated and flexible high-throughput method for quantification of bromine and iodine in dried serum spots (DSS) using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and an external aqueous standard calibration curve. The influence of serum matrix and laser ablation (LA) conditions on the analysis of bromine and iodine in DSS was researched systematically. METHODS: Aqueous standards without matrix matching were used for calibration to analyze bromine and iodine in serum by LA-ICP-MS. 5-µL volumes of the aqueous standard solution and serum samples in 10 times diluted concentration were deposited on the PTFE paper to form dried standard calibration spots (DSCS) and DSS, of less than 2 mm in diameter. LA was performed using a focused Nd:YAG laser beam in raster lineal scan mode. RESULTS: The limits of detection (LODs) for bromine and iodine in DSS were 0.23 and 0.03 mg L-1 , respectively. The relative standard deviation (RSD) for this method was less than 10%. The samples were also detected with matrix matching calibration by ICP-MS. The accuracy of the method was verified by statistical analysis of these results from ICP-MS and LA-ICP-MS. The accuracy is satisfactory with recoveries ranging from 81.5% to 118%. CONCLUSIONS: A novel and simple approach for high-throughput screening of bromine and iodine in DSS has been established by LA-ICP-MS. Calibration could be achieved using an aqueous standard solution instead of a matrix-matching solution. The method allowed analysis of low-volume biological samples without derivatization and decreased the risk of contamination or loss.
Asunto(s)
Bromo/sangre , Yodo/sangre , Terapia por Láser/métodos , Espectrometría de Masas/métodos , HumanosRESUMEN
This study investigates bromine (Br) concentration and its relationship with iodine concentration in serum samples of 86 horses. The mean serum Br concentration in horses pastured on green grass near the seashore was significantly higher (P<0.001) than that in horses pastured in a sand paddock. A significantly negative correlation (r=-0.479, P<0.01) between the serum Br and iodine concentrations was evident in the horses that pastured on green grass. The concentrations of several elements such as sodium and potassium were virtually constant in the serum. In addition, there were elements present below the detection limit of the analytical instruments used. In contrast, it was suggested that geological differences have a marked influence on serum Br concentrations in animals. Thus, we hypothesized that serum Br concentration in horses is a possible indicator reflecting geological differences.
Asunto(s)
Alimentación Animal , Bromo/sangre , Caballos/sangre , Yodo/sangre , Animales , Femenino , Japón , Masculino , Poaceae , TokioRESUMEN
α-Chlorofatty aldehydes (α-ClFALDs) and α-bromofatty aldehydes (α-BrFALDs) are produced in activated neutrophils and eosinophils. This study investigated the ability of α-BrFALD and α-ClFALD to react with the thiols of GSH and protein cysteinyl residues. Initial studies showed that 2-bromohexadecanal (2-BrHDA) and 2-chlorohexadecanal (2-ClHDA) react with GSH producing the same fatty aldehyde-GSH adduct (FALD-GSH). In both synthetic and cellular reactions, FALD-GSH production was more robust with 2-BrHDA compared with 2-ClHDA as precursor. NaBr-supplemented phorbol myristate acetate (PMA)-activated neutrophils formed more α-BrFALD and FALD-GSH compared with non-NaBr-supplemented neutrophils. Primary human eosinophils, which preferentially produce hypobromous acid and α-BrFALD, accumulated FALD-GSH following PMA stimulation. Mice exposed to Br2 gas had increased levels of both α-BrFALD and FALD-GSH in the lungs, as well as elevated systemic plasma levels of FALD-GSH in comparison to mice exposed to air. Similar relative reactivity of α-ClFALD and α-BrFALD with protein thiols was shown using click analogs of these aldehydes. Collectively, these data demonstrate that GSH and protein adduct formation are much greater as a result of nucleophilic attack of cysteinyl residues on α-BrFALD compared with α-ClFALD, which was observed in both primary leukocytes and in mice exposed to bromine gas.
Asunto(s)
Aldehídos/sangre , Bromo/sangre , Peroxidasa del Eosinófilo/sangre , Glutatión Transferasa/sangre , Peroxidasa/sangre , Animales , Bromo/administración & dosificación , Química Clic , Peroxidasa del Eosinófilo/metabolismo , Glutatión Transferasa/metabolismo , Voluntarios Sanos , Humanos , Ratones , Peroxidasa/metabolismo , Células RAW 264.7RESUMEN
A fast, accurate and precise method for the separation and determination of the total contents of drug-related Cl and Br in human blood plasma, based on high performance liquid chromatography - inductively coupled plasma - tandem mass spectrometry (HPLC-ICP-MS/MS), has been developed. The novel approach was proved to be a suitable alternative to the presently used standard methodology (i.e. based on a radiolabelled version of the drug molecule and radiodetection), while eliminating the disadvantages of the latter. Interference-free determination of (35)Cl has been accomplished via ICP-MS/MS using H2 as reaction gas and monitoring the (35)ClH2(+) reaction product at mass-to-charge ratio of 37. Br could be measured "on mass" at a mass-to-charge of 79. HPLC was relied on for the separation of the drug-related entities from the substantial amount of inorganic Cl. The method developed was found to be sufficiently precise (repeatability <10% RSD) and accurate (recovery between 95 and 105%) and shows a linear dynamic range (R(2)>0.990) from the limit of quantification (0.05 and 0.01 mg/L for Cl and Br in blood plasma, respectively) to at least 5 and 1mg/L for Cl and Br, respectively. Quantification via either external or internal standard calibration provides reliable results for both elements. As a proof-of-concept, human blood plasma samples from a clinical study involving a newly developed Cl- and Br-containing active pharmaceutical ingredient were analysed and the total drug exposure was successfully described. Cross-validation was achieved by comparing the results obtained on Cl- and on Br-basis.
Asunto(s)
Bromo/sangre , Cloro/sangre , Cromatografía Líquida de Alta Presión/métodos , Espectrometría de Masas en Tándem/métodos , HumanosRESUMEN
Bromine is one of the most abundant and ubiquitous trace elements in the biosphere and until recently had not been shown to perform any essential biological function in animals. A recent study demonstrated that bromine is required as a cofactor for peroxidasin-catalysed formation of sulfilimine crosslinks in Drosophila. In addition, bromine dietary deficiency is lethal in Drosophila, whereas bromine replenishment restores viability. The aim of this study was to examine the distribution and speciation of bromine in mammalian tissues and fluids to provide further insights into the role and function of this element in biological systems. In this study we used X-ray fluorescence (XRF) imaging and inductively coupled plasma-mass spectrometry (ICP-MS) to examine the distribution of bromine in bovine ovarian tissue samples, follicular fluid and aortic serum, as well as human whole blood and serum and X-ray absorption spectroscopy (XAS) to identify the chemical species of bromine in a range of mammalian tissue (bovine, ovine, porcine and murine), whole blood and serum samples (bovine, ovine, porcine, murine and human), and marine samples (salmon (Salmo salar), kingfish (Seriola lalandi) and Scleractinian coral). Bromine was found to be widely distributed across all tissues and fluids examined. In the bovine ovary in particular it was more concentrated in the sub-endothelial regions of arterioles. Statistical comparison of the near-edge region of the X-ray absorption spectra with a library of bromine standards led to the conclusion that the major form of bromine in all samples analysed was bromide.
Asunto(s)
Bromo/análisis , Bromo/sangre , Imagen Óptica , Espectroscopía de Absorción de Rayos X , Animales , Antozoos , Bovinos , Femenino , Humanos , Ratones , Imagen Óptica/métodos , Ovario/química , Salmón , Ovinos , Porcinos , Espectrometría de Masas en Tándem/métodos , Oligoelementos/análisis , Oligoelementos/sangre , Espectroscopía de Absorción de Rayos X/métodosRESUMEN
The quantitative determination of drugs in bio-samples may be interfered by the drug-related metabolites during the high-throughput LC-MS/MS analysis. When quantifying bromine or chlorine containing compounds, the 8¹Br/³7Cl isotopic forms of their mono-hydroxylated metabolites after in-source dehydration could produce ions which are isobaric with the precursor ions of the parent compounds at the 79Br/³5Cl isotopic form. In this report, we described the identification of an interfering hydroxylated metabolite of G004, a novel bromine-containing hypoglycemic agent, during LC-MS/MS analysis of plasma samples. Several different MRM transitions were tested and evaluated to minimize the metabolite influence on the quantification of G004. Furthermore, the standard addition method using incurred samples was used to evaluate the matrix effect caused by the interfering metabolite. The lower limit of quantitation of the established method was 0.2 ng/ml, which was 10 times lower than the existing one. The method was successfully applied to investigate the single-dosing pharmacokinetic profile of G004 in beagle dogs. The above results indicated that when quantifying chlorine or bromine containing compounds, evaluation of the interference from mono-hydroxylation or dehydrogenation metabolites should be undertaken, and if such metabolites existed, their impact on quantification of the parent compounds could be eliminated by the proper selection of the MRM transitions.
Asunto(s)
Bromo/análisis , Bromo/sangre , Hipoglucemiantes/sangre , Plasma/química , Espectrometría de Masas en Tándem/métodos , Animales , Perros , Hidroxilación , Hipoglucemiantes/metabolismo , Hipoglucemiantes/farmacocinética , Plasma/metabolismo , Espectrometría de Masa por Ionización de Electrospray/métodosRESUMEN
BACKGROUND: We encountered a case of bromism that was found to be due to pseudohyperchloremia. Hyperchloremia is known to be able to reveal existing bromism, but the fact that bromine (Br(-)) influences chloride (Cl(-)) in assays that use ion electrode machines is not widely known. METHODS: We assayed samples by an ion electrode method, using four types of machines. Different amounts of Cl(-) or Br(-) were added to each sample. RESULTS: With the addition of Cl(-) to the samples, the assayed Cl(-) concentrations were proportional to the amount of added Cl(-). With the addition of Br(-) to the samples, the assayed Cl(-) concentrations, as measured by all machines, were increased, but the amounts of the increase differed significantly, and were not proportional to the amount of Br(-) added. In particular, in the machine most markedly influenced by additional Br(-), the Cl(-) concentrations increased from 94.9 to 139.6 mEq/l with the addition of 10 mEq/l of Br(-). Conversely, in the least influenced machine, Cl(-) values increased from 95.0 to 103.0 mEq/l with the addition of 10 mEq/l of Br(-). CONCLUSION: The influence on the Cl(-) assay of the addition of Br(-) varied significantly between different ion electrode machines. Clinical nephrologists therefore need to be able to recognize the characteristics of the specific machines used in their hospitals.
Asunto(s)
Análisis Químico de la Sangre/instrumentación , Bromo/sangre , Cloruros/sangre , Electrodos , Adulto , Análisis Químico de la Sangre/métodos , Femenino , HumanosRESUMEN
After decades of neglect, bromide has recently been re-introduced in therapy as an effective anti-epileptic drug. The present paper describes the methodological optimization and validation of a method based on capillary zone electrophoresis for the rapid determination of bromide in serum using a high-viscosity buffer and a short capillary (10 cm). The optimized running buffer was composed of 90 mM sodium tetraborate, 10mM sodium chloride, pH 9.24 and 25% glycerol. The separation was carried out at 25 kV at a temperature of 20 degrees C. Detection was by direct UV absorption at 200 nm wavelength. The limit of detection (signal-to-noise ratio=5) in serum was 0.017 mM. The precision of the method was verified in blank serum samples spiked with bromide, obtaining intra-day and day-to-day tests, relative standard deviation values Asunto(s)
Bromo/sangre
, Electroforesis Capilar/métodos
, Glicerol/química
, Boratos/química
, Humanos
, Yodo/aislamiento & purificación
, Modelos Lineales
, Reproducibilidad de los Resultados
, Sensibilidad y Especificidad
, Viscosidad
RESUMEN
BACKGROUND: Bromides are still sold as sedatives, antitussives, and anticonvulsants in many countries. Bromovalerylurea is a bromide-containing sedative-hypnotic that is occasionally combined with non-steroidal anti-inflammatory drugs in over-the-counter products. Chronic intake of excessive bromovalerylurea can produce bromide intoxication, but acute bromovalerylurea intoxication presenting with myoclonic jerks has never been described. CASE REPORT: A 23-year-old woman was brought to our emergency department with unusual drowsiness. Her physical examination was normal except for frequent myoclonic jerks in all extremities that could be triggered by moving the patient or by noxious stimuli. Initial blood tests results were normal; the serum bromide concentration was 81.0 mg/L (reference <10 mg/L). Treatment with intravenous normal saline and furosemide resulted in gradual improvement in her drowsiness and myoclonic jerks. By the second hospital day, she was normal. A brain magnetic resonance imaging (MRI) was normal. At a 2-month follow-up visit, the patient had no neurological sequelae. DISCUSSION: Chronic bromide intoxication caused by long-term abuse of bromovalerylurea may present as psychiatric or neurologic abnormalities. Our case of acute bromovalerylurea intoxication presented with severe myoclonic jerks and lethargy. The serum bromide concentration was similar to the reported concentrations in acute bromide intoxications. Treatment with normal saline and diuretics results in increased clearance of bromide and an improvement in clinical effects. CONCLUSION: Myoclonic jerks may be one of the major presentations of acute bromovalerylurea intoxication. Physicians should consider bromide intoxication in the differential diagnosis of the causes of myoclonic jerks.
Asunto(s)
Bromisovalum/envenenamiento , Hipnóticos y Sedantes/envenenamiento , Mioclonía/inducido químicamente , Bromo/sangre , Diuréticos/uso terapéutico , Femenino , Estudios de Seguimiento , Furosemida/uso terapéutico , Humanos , Cloruro de Sodio/uso terapéutico , Intento de Suicidio , Adulto JovenRESUMEN
Concentrations of Br, Ca, Cl, K and Na in whole blood of dystrophin-deficient mouse [the Dmdmdx line] were determined using NAA, resulting in reference values that are relevant for clinical blood investigation. The comparison with human being whole blood values was also performed in order to establish possible indexes and similarities among the experimental and clinical applications.
Asunto(s)
Animales , Ratones , Análisis Químico de la Sangre , Bromo/sangre , Calcio/sangre , Potasio/análisis , Potasio/sangre , Sodio/sangreRESUMEN
Application of the Johnson bivariate S(B) distribution, or alternatively the S(BB) distribution, is presented here as a tool for the analysis of concentration data and in particular for characterizing the relationship between exposures and biomarkers. Methods for fitting the marginal S(B) distributions are enhanced by maximizing the Shapiro-Wilk W statistic. The subsequent goodness of fit for the S(BB) distribution is evaluated with a multivariate Z statistic. Median regression results are extended here with methods for calculating the mean and standard deviation of the conditional array distributions. Application of these methods to the evaluation of the relationship between exposure to airborne bromopropane and the biomarker of serum bromide concentration suggests that the S(BB) distribution may be useful in stratifying workers by exposure based on using a biomarker. A comparison with the usual two-parameter log-normal approach shows that in some cases the S(BB) distribution may offer advantages.
Asunto(s)
Biomarcadores/análisis , Exposición a Riesgos Ambientales/análisis , Contaminantes Ambientales/análisis , Contaminantes Ocupacionales del Aire/análisis , Bromo/sangre , Bromo/orina , Humanos , Hidrocarburos Bromados/análisis , Leucocitos/química , Modelos Estadísticos , Exposición Profesional/análisis , ProbabilidadRESUMEN
Bromide intoxication today is an infrequent disease, but preparations containing bromide are still available in nonprescription compounds, on the French market. We report a casewith bromide intoxication due to daily over intake (approximately 20 tablets per day; i.e. total elemental bromide intake approximately 6 g/day) of calcium bromo-galactogluconate (Calcibronat) for 1.5 months. A 30-year-old woman with a long history of psychotropic drug abuse was hospitalized in a psychiatric department for neuropsychological manifestations. She presented a seriously disturbed mental status with confusion, disorientation, auditory and visual hallucinations, and loss of short-time memory. A markedly increased serum bromide level of 1717 mg/L (21.5 mEq/L) measured on the first day after her admission confirmed the diagnosis of chronic bromism suspected based on her symptomatology. During her hospitalization, bromide plasma concentrations were measured and monitored using inductively coupled plasma mass spectrometry, a sensitive and very specific method. After withdrawal of the drug, the symptoms improved within 8 days. Serial bromide concentrations gradually declined throughout nearly 2 months of monitoring, until she was discharged from the hospital. We found an elimination half-life of bromide in blood of approximately of 10 days. This case demonstrates that, while today bromism occurs infrequently, it should still be included in the differential diagnosis of neuropsychiatric symptoms.
Asunto(s)
Bromuros/envenenamiento , Bromo/envenenamiento , Adulto , Bromuros/farmacocinética , Bromo/sangre , Sobredosis de Droga , Femenino , Francia , Semivida , Alucinaciones/inducido químicamente , Alucinaciones/psicología , Humanos , Trastornos de la Memoria/inducido químicamente , Trastornos de la Memoria/psicología , Síndromes de Neurotoxicidad/etiología , Síndromes de Neurotoxicidad/psicología , Medicamentos sin Prescripción/envenenamiento , Trastornos Relacionados con Sustancias/complicacionesRESUMEN
Wistar male rats were exposed to 2000 ppm of methyl bromide gas for one hour (single exposure experiment) or 300 ppm of the gas for 6 hours a day, 3 days a week for 4 or 8 weeks (repeated exposure experiment) to investigate the metabolism of inhaled methyl bromide. After the exposure was completed, the bromine ion concentration in serum was measured up to 60 days. The serum bromine ion concentration was determined by a headspace gas chromatography-mass spectrometry after converting bromine ion to methyl bromide by adding dimethyl sulfate in the serum samples. In the single exposure experiment, the bromine ion concentration decreased quickly within one day after the end of the exposure, and then began to decrease gradually. In the repeated exposure experiment, on the other hand, the bromine ion concentration decreased almost exponentially. A two-compartment model was applied to analyze the clearance rate of bromine ion. The biological half time of serum bromine ion was 9.1 days for the single exposure and 5.4 days for the repeated exposure. The amount of cytochrome P450 (CYP) in liver microsomes was measured after the end of exposure. CYP in liver was not significantly different after the repeated exposure but it decreased after the single exposure.
Asunto(s)
Bromo/farmacocinética , Hidrocarburos Bromados/farmacología , Hígado/metabolismo , Administración por Inhalación , Animales , Encéfalo/metabolismo , Bromo/sangre , Sistema Enzimático del Citocromo P-450/metabolismo , Semivida , Hidrocarburos Bromados/metabolismo , Hígado/efectos de los fármacos , Masculino , Microsomas Hepáticos/enzimología , Ratas , Ratas WistarRESUMEN
Chronic parasitic infections are a major risk factor for cancer development in many underdeveloped countries. Oxidative damage of DNA may provide a mechanism linking these processes. Eosinophil recruitment is a hallmark of parasitic infections and many forms of cancer, and eosinophil peroxidase (EPO), a secreted hemoprotein, plays a central role in oxidant production by these cells. However, mechanisms through which EPO may facilitate DNA oxidation have not been fully characterized. Here, we show that EPO effectively uses plasma levels of bromide as a cosubstrate to brominate bases in nucleotides and double-stranded DNA, forming several stable novel brominated adducts. Products were characterized by HPLC with on-line UV spectroscopy and electrospray ionization tandem mass spectrometry (LC/ESI/MS/MS). Ring assignments for brominated purine bases as their 8-bromo adducts were identified by NMR spectroscopy. Using stable isotope dilution LC/ESI/MS/MS, we show that while guanine is the preferred purine targeted for bromination as a free nucleobase, 8-bromoadenine is the major purine oxidation product generated following exposure of double-stranded DNA to either HOBr or the EPO/H(2)O(2)/Br(-) system. Bromination of nucleobases was inhibited by scavengers of hypohalous acids such as the thioether methionine, but not by a large molar excess of primary amines. Subsequently, N-monobromoamines were demonstrated to be effective brominating agents for both free nucleobases and adenine within intact DNA. A rationale for selective modification of adenine, but not guanine, in double-stranded DNA based upon stereochemical criteria is presented. Collectively, these results suggest that specific brominated DNA bases may serve as novel markers for monitoring oxidative damage of DNA and the nucleotide pool by brominating oxidants.
Asunto(s)
Adenina/análogos & derivados , Aductos de ADN/metabolismo , Desoxirribonucleósidos/metabolismo , Eosinófilos/enzimología , Peroxidasas/metabolismo , Adenina/metabolismo , Animales , Bromatos/metabolismo , Bromo/sangre , Bromo/metabolismo , Catálisis , Desoxiguanosina/análogos & derivados , Desoxiguanosina/metabolismo , Peroxidasa del Eosinófilo , Eosinófilos/metabolismo , Humanos , Peróxido de Hidrógeno/metabolismo , Espectrometría de Masas , Resonancia Magnética Nuclear Biomolecular , Ácidos Nucleicos Heterodúplex/metabolismo , Oxidantes/metabolismo , Oxidación-Reducción , Nucleósidos de Purina/química , Nucleósidos de Purina/metabolismo , PorcinosAsunto(s)
Anticonvulsivantes/farmacocinética , Bromuros/farmacocinética , Cloro/sangre , Monitoreo de Drogas/métodos , Epilepsia/metabolismo , Compuestos de Potasio/farmacocinética , Adolescente , Anticonvulsivantes/uso terapéutico , Bromuros/uso terapéutico , Bromo/sangre , Niño , Preescolar , Epilepsia/tratamiento farmacológico , Femenino , Humanos , Lactante , Masculino , Compuestos de Potasio/uso terapéuticoRESUMEN
Detection of specific reaction products is a powerful approach for dissecting out pathways that mediate oxidative damage in vivo. Eosinophil peroxidase (EPO), an abundant protein secreted from activated eosinophils, has been implicated in promoting oxidative tissue injury in conditions such as asthma, allergic inflammatory disorders, cancer, and helminthic infections. This unique heme protein amplifies the oxidizing potential of H2O2 by utilizing plasma levels of Br- as a cosubstrate to form potent brominating agents. Brominated products might thus serve as powerful tools for identifying sites of eosinophil-mediated tissue injury in vivo; however, structural identification and characterization of specific brominated products formed during EPO-catalyzed oxidation have not yet been reported. Here we explore the role of EPO and myeloperoxidase (MPO), a related leukocyte protein, in promoting protein oxidative damage through bromination and demonstrate that protein tyrosine residues serve as endogenous traps of reactive brominating species forming stable ring-brominated adducts. Exposure of the amino acid L-tyrosine to EPO, H2O2, and physiological concentrations of halides (100 mM Cl-, =100 microM Br-) produced two new major products with distinct retention times on reverse phase HPLC. The products were identified as 3-bromotyrosine and 3, 5-dibromotyrosine by electrospray ionization mass spectrometry and multinuclear (1H and 15N) NMR spectroscopy. Formation of the ring-brominated forms of the amino acid occurred readily at neutral pH with the enzymatic system and a variety of reactive brominating species, including HOBr/OBr-, N-bromoamines, and N,N-dibromoamines. Addition of primary amines (e.g., Nalpha-acetyllysine and taurine) to L-tyrosine exposed to either HOBr/OBr- or the EPO-H2O2-Br- system enhanced phenolic ring bromination, suggesting N-bromoamines are preferred brominating intermediates in these reactions. Reduction of N-bromoamines (e.g., Nalpha-acetyl,Nepsilon-bromolysine) by L-tyrosine was shown to result in the loss of reactive halogen with a near stoichiometric increase in the level of tyrosine ring bromination (i.e., carbon-bromine bonds). Although both EPO and MPO could use Br- to halogenate protein tyrosine residues in vitro, only EPO effectively brominated the aromatic amino acid at physiological levels of halides and H2O2. Collectively, these results suggest that 3-bromotyrosine and 3,5-dibromotyrosine are attractive candidates for serving as molecular markers for oxidative damage of proteins by reactive brominating species in vivo. They also suggest that in biological mixtures where amine groups are abundant, the trapping of EPO-generated HOBr/OBr- as N-bromoamines will serve to effectively "funnel" reactive brominating equivalents to stable ring-brominated forms of tyrosine.
Asunto(s)
Eosinófilos/metabolismo , Peroxidasas/metabolismo , Tirosina/análogos & derivados , Animales , Bromo/sangre , Bromo/metabolismo , Cloruros/sangre , Cromatografía Líquida de Alta Presión , Peroxidasa del Eosinófilo , Eosinófilos/enzimología , Eosinófilos/patología , Humanos , Concentración de Iones de Hidrógeno , Oxidación-Reducción , Porcinos , Tirosina/metabolismoRESUMEN
The use of serum bromine concentration (SeBr) as a measure of exposure was examined in an occupational cohort. Associations with work site, department type, chemical handling, and occupation, as proxy measures of exposure, were studied. SeBr was associated with all of these measures. SeBr was also associated with various demographic characteristics (age, country of origin, and education) in men. In women, there was no association between SeBr and age, country of origin, or education. The use of SeBr as a measure of exposure is discussed. The conclusion is that the exposure to bromine can be assessed by regular monitoring of SeBr.