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At least 19 recordsLinked to original sources
PubMed1997

Bromine-, chlorine-, and mixed halogen-substituted 4-methyl-2(5H)-furanones: synthesis and mutagenic effects of halogen and hydroxyl group replacements.

The versatility of 4-(hydroxymethyl)-2(5H)-furanone as a starting point for the synthesis of several bromine and mixed halogen analogues of the potent water mutagen 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX) has been demonstrated. However, in some preparations the yields of desired products were lower for bromine- than chlorine-substituted counterparts. A total of 12 bromine-, chlorine-, and mixed halogen-substituted 4-methyl-2(5H)-furanones were tested repeatedly in 10 independent experiments for levels of Salmonella typhimurium (TA100) mutagenicities. The purpose of these experiments was to determine the mutagenic response to changing halogen content, type, and position as well as to learn the measure of these responses in the presence and absence of the C-5 OH group. Mutagenicities reached levels of 10(3) and 10(2) rev/nmol for all trihalo- and dihalo-4-methyl-5-hydroxy-2(5H)-furanones, respectively, notwithstanding substitutions by bromine or chlorine. Trihalides lacking the C-5 hydroxyl group possessed mutagenicities of the order of 10(2) rev/nmol, while hydroxyl group absence in the dihalides resulted in potency levels of slightly less than 10 rev/ nmol. Pairwise comparisons of compound mutagenicities showed that overall the C-5 H-by-OH replacement and, next in importance, increasing the number of C-6 halogens from one to two resulted in the greatest enhancements of mutagenicities. However, in comparing compound pairs within two different sets of four di- and trihalides, it was observed that replacement of a C-5 H by OH enhanced mutagenicity more for the dihalides than the trihalides indicating that increasing the C-6 halogen number simultaneously with replacing C-5 H by OH results in a nonlinear, additive enhancement. For fewer than half of the compound pairs compared, changing the C-6 halogen from chlorine to bromine resulted in small increases in mutagenicity, and for the remaining compound pairs, no increase could be discerned. This result points to the relative unimportance of only C-6 halogen type as a determinant of mutagenicity. Similarly, no impact on mutagenicity was observed for changing only the halogen type attached to C-3.

Furans↗
PubMed2002

Crystal engineering for topochemical polymerization of muconic esters using halogen-halogen and CH/pi interactions as weak intermolecular interactions.

We now report the molecular and crystal structure design of muconic ester derivatives on the basis of crystal engineering using halogen-halogen contacts and CH/pi interactions. The solid-state photoreaction pathway of the dibenzyl (Z,Z)-muconates as the 1,3-diene dicarboxylic acid monomers depends on the structure of the ester groups. The substitution of a halogen atom for the aromatic hydrogen of a benzyl group induces topochemical polymerization to produce stereoregular polymers in a crystalline form, whereas the unsubstituted benzyl derivative isomerizes to yield the corresponding E,E isomer under similar conditions. The topochemical polymerization process is directly confirmed by the fact that the single-crystal structures before and after the polymerization are very similar to each other. From the crystal structure analysis for a series of substituted benzyl (Z,Z)- and (E,E)-muconates, it has been revealed that the planar diene moieties are closely packed to form a columnar structure in the crystals. The stacking of the polymerizable monomers is characterized by a stacking distance of 4.9-5.2 A along the columns. This structure is supported by a halogen-halogen interaction between the chlorine or bromine atoms introduced at the p position of the benzyl groups in addition to an aromatic stacking due to the CH/pi interaction between the benzylic methylene hydrogens and aromatic rings. The design of a monomer packing corresponds to the type and position of the introduced halogen atom and also the polymorphs. To make a stacking distance of 5 A using both halogen-halogen and CH/pi interactions as supramolecular synthons is important for the molecular design of muconic ester derivatives appropriate for topochemical polymerization.

Journal Article↗
PubMed1995

The effect of varying halogen substituent patterns on the cytochrome P450 catalysed dehalogenation of 4-halogenated anilines to 4-aminophenol metabolites.

The cytochrome P450 catalysed biotransformation of 4-halogenated anilines was studied in vitro with special emphasis on the dehalogenation to 4-aminophenol metabolites. The results demonstrated that a fluorine substituent at the C4 position was more easily eliminated from the aromatic ring than a chloro-, bromo- or iodo-substituent. HPLC analysis of in vitro biotransformation patterns revealed that the dehalogenation of the C4-position was accompanied by formation of non-halogenated 4-aminophenol, without formation of NIH-shifted metabolites. Changes in the apparent Vmax for the microsomal oxidative dehalogenation appeared to correlate with the electronegativity of the halogen substituent at C4, the fluorine substituent being the one most easily eliminated. A similar decrease in the rate of dehalogenation from a fluoro- to a chloro- to a bromo- to an iodo-substituent was observed in a system with purified reconstituted cytochrome P450 IIB1, in a tertiair butyl hydroperoxide supported microsomal cytochrome P450 system as well as in a system with microperoxidase 8. This microperoxidase 8 is a haem-based mini-enzyme without a substrate binding site, capable of catalysing cytochrome P450-like reaction chemistry. Together, these results excluded the possibility that the difference in the rate of dehalogenation with a varying C4-halogen substituent arose from a change in the contribution of cytochrome P450 enzymes involved in oxidative dehalogenation with a change in the halogen substituent. Rather, they strongly suggested that the difference was indeed due to an intrinsic electronic parameter of the various C4 halogenated anilines dependent on the type of halogen substituent. Additional in vitro experiments with polyfluorinated anilines demonstrated that elimination of the C4-fluorine substituent became more difficult upon the introduction of additional electron withdrawing fluorine substituents in the aniline-ring. 19F-NMR analysis of the metabolite patterns showed that the observed decrease in 4-aminophenol formation was accompanied by a metabolic switch to 2-aminophenols and N-hydroxyanilines, while products resulting from NIH-type mechanisms were not observed. For a C4-chloro-, bromo-, or iodo-substituted 2-fluoroaniline the Vmax for the oxidative dehalogenation was reduced by the additional electron withdrawing fluorine substituent at the C2 position in a similar way.(ABSTRACT TRUNCATED AT 400 WORDS)

Aminophenols↗
PubMed2003

Sense or no-sense of the sum parameter for water soluble "adsorbable organic halogens" (AOX) and "absorbed organic halogens" (AOX-S18) for the assessment of organohalogens in sludges and sediments.

"AOX" is the abbreviation of the sum parameter for water soluble "adsorbable organic halogens" in which 'A' stands for adsorbable, 'O' for organic and 'X' for the halogens chlorine, bromine and iodine. After the introduction of the AOX in 1976, this parameter has been correctly used for "real" AOX constituents (DDT and its metabolites, PCBs, etc.) but also misused for non-adsorbable adsorbed OX-compounds, mostly high molecular organohalogens in plants and even to inorganic compounds being neither organic nor adsorbable. The question of natural "Adsorbable Organic Halogens" (AOX) formed by living organisms and/or during natural abiogenic processes has been definitively solved by the known existence of already more than 3650 organohalogen compounds, amongst them the highly reactive, cancerogenic vinyl chloride (VC). The extension of the AOX to AOX-S18 for Sludges and Sediments, in which A stands for adsorbed (not for adsorbable) is questionable. It includes the most important water insoluble technical organochlorine product: polyvinyl chloride, PVC. In addition to organic halogens it also includes inorganic, mineralogenic halides, incorporated mainly in the crystal lattice of fine grained phyllosilicates, the typical clay minerals (kaolinite, montmorillonite, illite and chlorite) which are main constituents of sediments and sedimentary rocks representing the major part of the sedimentary cover of the earth. Other phyllosilicates, biotite and muscovite, major constituents of granites and many metamorphic rocks (gneiss and mica schist) will also contribute to the AOX-S18 especially in soils as result of weathering processes. Since chlorine is incorporated into the mineral structure and, as a consequence, not soluble by the nitric acid analytical step (pH 0.5) of the S18 determination, it will account to the AOX-S18 in the final charcoal combustion step at temperatures >950 degrees C. After heavy rainfalls sewage sludge composition is strongly influenced by mineralogenic components derived from the erosion of fine grained sediments or soils. Assuming 50% geogenic particles with a mean Cl concentration of 103 mg/kg (as in shales and clays) the mineralogenic Cl-content could add about 50 mg/kg to the organic AOX in sewage sludge. The occurrence of insoluble and non-adsorbable PVC in sewage sludge exhibits the same problems as the mineralogenic constituents: a detection as AOX-S18 is possible when the final high temperature analytical step is applied. Plants as major sources of organohalogens have never been doubted. Only recently [Science 295 (2002) 985] based on the determination of the form of Cl with near-edge X-ray adsorption fine structure (NEXAFS) spectroscopy and extended X-ray adsorption showed the variations in the inorganic Cl(-) and organo-Cl compounds with increasing humification of plant leaves from "fresh leaves--senescent leaves on plants--senescent leaves on soil--powdered top soil--isolated soil humus". His finding of exclusively inorganic Cl(-) in the starting material (fresh leaves) is controverse to our earlier results indicating the presence of ionic inorganic Cl together with water insoluble absorbed organohalogens (AOX-S18) in eight different macrophytes of both terrestrial and marine environments. Our research on AOX in interstitial water of anaerobic limnic sediments has led to the role of bromine playing in the diagenesis of the organic matter of sediments. In sediments of Lake Constance Br(-) concentrations in lake water at the sediment water interface increased from <0.01 to 0.25 mg/l in the pore water at 77 cm sediment depth. In the Neckar River a Br concentrations of 0.02 mg/l at the water/sediment interface increasing to 0.74 mg/l in pore water in 85 cm depth was found. Here a parallel development could be found with ammonium concentration and alkalinity. The very high positive correlation ammonium:bromide and bromide:alkalinity leads to the conclusion, that bromine, originally a high molecular constituent of the organic matter, is released as bromide during an early dehalogenation stage of diagenesis. The mlusion, that bromine, originally a high molecular constituent of the organic matter, is released as bromide during an early dehalogenation stage of diagenesis. The main general reason to discard the AOX sum parameter as a whole lies in the fact, that adsorbable halogenated substances cannot a priori be categorized as natural/anthropogenic, biotic/abiotic, harmful/harmless. If applied to sludges and sediments, adsorbed organohalogens are not water soluble and therefore not adsorbable, and mineralogenic halogens (X) are neither organic nor adsorbable, and therefore by definition no AOX.

Absorption↗
PubMed2003

Low nanogram per liter determination of halogenated nonylphenols, nonylphenol carboxylates, and their non-halogenated precursors in water and sludge by liquid chromatography electrospray tandem mass spectrometry.

A new LC-MS-MS method for quantitative analysis of nonylphenol (NP), nonylphenol carboxylates (NPECs), and their halogenated derivatives: brominated and chlorinated nonylphenols (BrNP, ClNP), brominated and chlorinated nonylphenol carboxylates (BrNPE(1)C and ClNPE(1)C) and ethoxycarboxylates (BrNPE(2)C and ClNPE(2)C) in water and sludge has been developed. Electrospray negative ionization MS-MS was applied for the identification of above mentioned compounds. Upon collision-induced dissociation, their deprotonated molecules gave different fragments formed by the cleavage of the alkyl moiety and/or (ethoxy)carboxylic moiety. For halogenated compounds a highly diagnostic characteristic pattern of isotopic doublet signals was obtained and fragmentation yielded, in addition to above mentioned ions, [Br](-) and [Cl](-), respectively. Quantitative analysis was done in the multiple reaction monitoring (MRM) mode, using two specific combinations of a precursor-product ion transitions for each compound. Additionally, for halogenated compounds two specific channels for each transition reaction, corresponding to two isotopes, were monitored and the ratio of their abundances used as an identification criterion. The method has been validated in terms of sensitivity, selectivity, accuracy, and precision and was applied to the analysis of water and sludge samples from drinking water treatment plant (DWTP) of Barcelona (Catalonia, NE Spain). Halogenated NP and NPECs were detected in prechlorinated water in concentrations up to 315 ng/L, BrNPE(2)C being the most abundant compound. In the DWTP effluent non-halogenated compounds were detected at trace levels (85, 12 and 10 ng/L for NP, NPE(1)C, and NPE(2)C, respectively), whereas concentration of halogenated derivatives never exceeded 10 ng/L. Nonylphenol, brominated and chlorinated NPs were found in flocculation sludge in concentrations of 150, 105, and 145 microg/kg, respectively. Acidic polar metabolites were found in lower concentrations up to 20 microg/kg.

Carboxylic Acids↗
PubMed1982

Chloroperoxidase halogenation reactions. Chemical versus enzymic halogenating intermediates.

In the absence of organic substrates, chloroperoxidase catalyzes the peroxidation of chloride and bromide ion to molecular chlorine and bromine. However, these molecular species are not formed as intermediates in the enzymic halogenation of organic halogen-acceptor substrates. The rate of oxidation of chloride to its respective molecular species is considerably slower than the rate of enzymic chlorination of acceptor substrates. Furthermore, differences are observed in substrate specificities between enzymic and chemical halogenation reactions. Thiourea and methionine are substrates in chloride-dependent oxidation reactions catalyzed by chloroperoxidase and are preferred at least 50:1 and 30:1 respectively over 2- chlorodimedone. Corresponding nonenzymic reaction preferences for the oxidation of thiourea versus 2-chlorodimedone chlorination are only 2:1 with hypochlorite and 3:1 with molecular chlorine. Also, hypochlorite shows essentially no preference for methionine compared with 2-chlorodimedone. In the bromide-dependent reactions catalyzed by chloroperoxidase, bromine is formed at a rate equivalent to that of the bromination of acceptor substrates. However, the specificity of the bromide-dependent oxidation of methionine versus the bromination of 2-chlorodimedone by chloroperoxidase is 4:1. This value is significantly higher than the ratio in reactions of these two substrates with molecular bromine, which is essentially 1:1. A general reaction scheme for all reactions of chloroperoxidase with its halogen-acceptor substrates is proposed. This process involves the initial formation of Compound I and its subsequent conversion into an iron (III) hypohalite halogenating intermediate.

Chloride Peroxidase↗
PubMed1982

Halogenated biphenyls as AHH inducers: effects of different halogen substituents.

4'-Iodo-, 4'-bromo-, 4'-chloro- and 4'-fluoro-2,3,4,5-tetrachlorobiphenyl were administered to immature male Wistar rats and the effects of this homologous series of 4'-halo-2,3,4,5-tetrachlorobiphenyls on the microsomal drug-metabolizing enzymes were determined. All the halogenated biphenyls increased microsomal benzo[a]pyrene hydroxylase (or aryl hydrocarbon hydroxylase, AHH), ethoxyresorufin (ER) O-deethylase and dimethylaminoantipyrine (DMAP) N-demethylase. The effects of the 4'-halo-2,3,4,5-tetrachlorobiphenyls on the microsomal enzyme activities and on the relative peak intensities and spectral shifts of the reduced cytochrome P-450:CO and ethylisocyanide (EIC) binding difference spectra were similar to those observed after coadministration of phenobarbitone (PB) and 3-methylcholanthrene (MC). The relative activities of the halogenated biphenyls were determined using two in vitro assays; namely cytochrome P-448 associated induction in rat hepatoma H-4-II E cells in culture and competitive binding to the hepatic cytosolic Ah receptor protein from male Wistar rats. Dose-response experiments for the iodo, bromo, chloro and fluoro analogs gave EC50(M) values of 8.5 x 10(-9), 6.6 x 10(-8), 5.7 x 10(-7), and 3.3 x 10(-5), and 1.5 x 10(-6), 2.5 x 10(-6), 4.1 x 10(-6) and 2.5 x 10(-5) for the Er O-deethylase induction and receptor binding assays respectively. The relative potencies of the 4'-halo-2,3,4,5-tetrachlorobiphenyls followed the order I greater than Br greater than Cl greater than F for both assays and differences in the EC50 values for the iodo and fluoro analogs were greater than three orders of magnitude for ER O-deethylase induction in rat hepatoma cells in culture. One possible explanation for these effects may be associated with differences in the polarizability of the laterally substituted halogen groups. However, other differences in the physico-chemical properties of the halogen atoms may also be important.

Animals↗
PubMed2002

The first halogen-substituted cyclotrigermenes: a unique halogen walk over the three-membered ring skeleton and facial stereoselectivity in the Diels-Alder reaction.

Dark red crystals of the halogen-substituted cyclotrigermenes [(tBu3Si)3Ge3X; X = Cl, Br, I] were obtained in good yields by the reaction of [(tBu3Si)3Ge3]+.TTFPB- (TTFPB- = tetrakis(2,3,5,6-tetrafluorophenyl)borate) with potassium halides (KCl, KBr, or KI) in diethyl ether. The crystal structures of the halogen-substituted cyclotrigermenes reveal a cis-bent Ge=Ge double bond, caused by the introduction of the electronegative halogen atom on the sp3 germanium atom of cyclotrigermene. In solution, an intramolecular halogen migration over the three-membered ring skeleton was observed. Facial stereoselectivity in the Diels-Alder reaction of new cyclotrigermenes with 2,3-dimethyl-1,3-butadiene is also reported.

Journal Article↗
PubMed1999

Ascorbic acid treatment to reduce residual halogen-based oxidants prior to the determination of halogenated disinfection byproducts in potable water.

Treatment of potable water samples with ascorbic acid has been investigated as a means for reducing residual halogen-based oxidants (disinfectants), i.e. HOCl, Cl2, Br2 and BrCl, prior to determination of EPA Method 551.1A and 551.1B analytes. These disinfection byproducts include certain haloalkanes, haloalkenes, haloethanenitriles, haloaldehydes, haloketones and trichloronitromethane. When used as a dehalogenating agent immediately before analysis, only one analyte, 2,2,2-trichloroethanediol (chloral hydrate), is significantly decomposed. Ascorbic acid is superior to thiosulfate and sulfite as it does not destroy trichloroethanenitrile (trichloroacetonitrile), trichloronitromethane (chloropicrin) or dibromoethanenitrile (dibromoacetonitrile). Unlike ammonia or amines, it is not nucleophilic and cannot form hemiaminals (carbinolamines) with carboxaldehydes and ketones. Ascorbic acid treatment can rapidly consume (reduce) large amounts of active (oxidizing) halogen compounds, producing only inorganic halides and dehydroascorbic acid and not additional halogenated organic molecules.

Ascorbic Acid↗
PubMed2002

Comparative study of structure-properties relationship for novel beta-halogenated lanthanide porphyrins and their nickel and free bases precursors, as a function of number and nature of halogens atoms.

The synthetic route of partially beta-halogenated via a "metal-assisted" reaction and perhalogenated terbium complexes is described. This protocol allows the facile insertion of the halogens (bromines or chlorides) to the porphyrin peripheral positions. The electronic absorption spectra and the redox potentials of the free porphyrins as well as the terbium complexes are dramatically affected as the number of halogen atoms increase. In fact, two antagonistic effects are responsible for that, the inductive and the distortion effects on the porphyrin ring. They result in a red shift for the Soret band and a stabilization/destabilization of the HOMOs/LUMOs which in turn is manifested by variations on the redox potentials. The novel crystal structure of the Ni(Cl(8)TPP) is discussed in great detail and compared with the previously reported structures of Tb(Cl(8)TPP) (OAc)(DMSO)(2) x 3PhCH(3) x MeOH and H(2)(Br(8)TPP), as well as with other perhalogenated nickel porphyrins available in the literature.

Journal Article↗
PubMedDate not supplied

[The role of halogenation in the electro-oxidation of halogenated anilines in acetonitrile as the solvent].

The 4-halogeno-, 2,4-dihalogeno- and 2,4,6-trihalogenoanilines were the model substances of the research described. Acetonitrile being one of the most popular aprotic solvent was used. The halogeno monomers were chloro and bromoanilines. The electrodimerised substrate is stabilised by rejecting halogenide ion and protons. The rejected halogenide ions are oxidisable more easier compared to the substrate therefore the halogene formed substitutes both the substrate, and the dimer as well. The protons formed during the oxidation bind by the strong base monomer primary amine. Because of these not only a simple electrodimerisation will take place, but protonised monomers, higher halogenated monomers, and the corresponding dimer molecules are formed in the solution.

Acetonitriles↗
PubMed1979

Potential halogenated industrial carcinogenic and mutagenic chemicals. II. Halogenated saturated hydrocarbons.

The halogenated saturated hydrocarbons analogously to the previously considered halogenated unsaturated hydrocarbons (Part I) possess considerable utility in a broad spectrum of applications including; solvents, dry-cleaning fluids, refrigerants, fumigants, degreasing agents, propellants and intermediates in the production of other chemicals, textiles and plastics. Methyl chloride, methylene chloride, chloroform, carbon tetrachloride, methyl chloroform, 1,1,2-trichloroethane, hexachloroethane, ethyl chloride and fluorocarbons were reviewed principally in terms of their synthesis (or occurrence), areas of application, stability, distribution, reactivity, levels of exposure, populations at risk, carcinogenicity, mutagenicity and metabolism.

Animals↗
PubMed2003

Non-polar halogenated natural products bioaccumulated in marine samples. II. Brominated and mixed halogenated compounds.

Several identified and potential natural brominated bioaccumulative compounds were studied in this work. 4,6-dibromo-2-(2('),4(')-dibromo)phenoxyanisole (BC-2) previously detected in Australian marine mammals and isolated from sponges, was synthesized. Two byproducts (a tetrabromo isomer and a tribromo congener) were investigated as well. The byproducts of the synthesis were not identified in the environmental samples investigated. Previously described natural brominated compounds (BC-1, BC-2, BC-3, BC-10, BC-11, MHC-1) and anthropogenic brominated diphenyl ethers (BDE-47, BDE-99, BDE-100, BDE-154) were detected in a sample of human milk. The sample was from a woman from the Faeroe Islands who frequently consumed fish as well as whale blubber and meat. The most abundant compound originated from the natural tetrabromo phenoxyanisole BC-3 which may have a 3:1 distribution of bromine on the two phenyl units. This sample also accumulated a dibromochloroanisole, as well as a previously unknown mixed halogenated compound (MHC-X) and an unknown, most likely aromatic brominated compound. Co-elutions on a DB-5 column were found for BDE-99 and BC-11 as well as BDE-154 and the unknown brominated compound. This suggests that quantification of these two compounds has to be carried out carefully.Two samples of lower trophic level, namely Baltic cod liver and Mexican mussel tissue, were investigated as well. The cod liver samples contained BDE congeners but also abundant signals for the natural 2,3,3('),4,4('),5,5(')-heptachloro-1(')-methyl-1,2(')-bipyrrole Q1 and tribromoanisole (TBA). The mussel sample contained Q1, TBA, another halogenated anisole, BC-1, BC-2, and BC-3, as well as additional, potential natural brominated compounds in the elution range of tribromophenoxyanisoles.

Animals↗
PubMed1982

Acute inhalation toxicity of some halogenated and non-halogenated hydrocarbons.

1 The relative potency of effect of a wide range of halogenated and unsubstituted hydrocarbons on the central nervous system (CNS) and the heart of experimental animals have been determined. 2 The chemicals used caused either stimulation or depression of the rat CNS after 10 minutes' inhalation of concentrations ranging from 0.24% to greater than 80% (v/v), and cardiac sensitization in dogs after 5 minutes' inhalation of 0.12% to approximately 80% (v/v). 3 The toxicity could not be correlated with chemical structure, molecular weight, the presence or absence of various halogen atoms or the degree of saturation, but it was inversely related to the saturated vapour pressure. When the results were expressed on a thermodynamic scale the chemicals had similar potencies at relative saturations of 0.004 to 0.04 4 It is suggested that the effects of these chemicals on the CNS and the heart are probably structurally non-specific, and the chemicals may be regarded as physical toxicants whose effects are predictable from their physico-chemical properties.

Animals↗
PubMed1984

Mammary transfer and metabolism in the rat of halogenated fatty acids of halogenated olive oil.

To assess possible incorporation of halogenated fatty acids into the neonate via the milk, a 4-day study was carried out in which lactating Wistar rats were orally dosed with either brominated olive oil (BOO) (0.6 g/kg body wt/day) or chlorinated olive oil (COO) (0.4 g/kg body wt/day) for the first 4 days. On days 1-5 inclusive 2 pups per litter were sacrificed and the stomach curd and livers analyzed for halogenated fatty acids by gas liquid chromatography (GLC). On day 5 all dams also were sacrificed and their livers and adipose tissue similarly analyzed. With BOO, brominated fatty acids (bfa) accumulated in both the milk lipids and neonate liver lipids, and appeared to plateau on day 4 at levels of 2% and 5% respectively. In contrast to the BOO in which approximately 100% of the bfa was dibromostearic (DBS), the milk bfa comprised 79% (DBS), 9% dibromopalmitic (DBP) and 12% dibromomyristic (DBM) acids, suggesting maternal metabolism to the shorter chain brominated acids. In the neonate liver lipids the bfa composition was 47% (DBS), 12% (DBP) and 41% (DBM), suggesting either further metabolism in the neonate and/or preferential accumulation of the shorter chain brominated acids. The analysis of maternal tissue indicated very low bfa residues, contrary to previous studies in non-lactating rats. Similar results were obtained with COO.

Adipose Tissue↗
PubMed1992

In vivo studies on halogen compound interactions. IV. Interaction among different halogen derivatives with and without synergistic action on liver toxicity.

The liver toxicity of several halogen compound mixtures have been tested. The compounds were selected on the basis of their metabolic pathways: carbon tetrachloride (CT) and trichlorobromomethane (TCBM) undergo a dehalogenation via P450-dependent enzyme system, 1,2-dichloroethane (DCE) and 1,2-dibromoethane (DBE) are mainly conjugated with the cytosolic glutathione (GSH) by means of the GSH-S-transferase. The mixture TCBM+DBE shows a more than additive action on lipid peroxidation and liver necrosis. TCBM, like CT, reduces the hepatic level of GSH-S-transferase, increasing the amount of DBE available for cytochrome P450-dependent metabolism, with the production of toxic metabolites. Thus, the behavior of the mixture TCBM+DBE is very similar to that of the mixture CT+DBE, previously reported. Mixtures composed of CT+TCBM and DCE+DBE do not show any synergistic effect on liver toxicity. The results allow one to conclude that the toxicity of mixtures of halogen compounds can be partly predicted on the basis of their metabolic pathways. When the metabolism is quite different, a synergistic toxicity can occur if one pathway interferes with a detoxification mechanism of the other compound. If the two metabolisms are very similar they produce, at most, an additive toxicity.

Alanine Transaminase↗
PubMed1979

Potential halogenated industrial carcinogenic and mutagenic chemicals. I. Halogenated unsaturated hydrocarbons.

The halogenated aliphatic hydrocarbons represent one of the most important categories of industrial chemicals from a consideration of use categories, production volume, environmental and toxicological considerations, and hence most importantly, potential population risk. The major unsaturated hydrocarbons reviewed, primarily in terms of their synthesis, utility, stability, distribution and levels of exposure as well as their reactivity, carcinogenicity, mutagenicity and metabolism, include: vinyl chloride, vinylidene chloride, trichloroethylene, perchloroethylene, chloroprene, trans-1,4-dichlorobutene, hexachlorobutadiene and allyl chloride.

Adult↗