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At least 19 recordsLinked to original sources
PubMed1994

Biphenyl compounds are hydroxyl radical scavengers: their effective inhibition for UV-induced mutation in Salmonella typhimurium TA102.

In our previous study, we found several hydroxylated biphenyl compounds have a great scavenging effect for hydroxyl radicals (.OH). In this study, to elucidate the relationship between generation of the .OH and photo-mutagenesis, six biphenyl compounds such as dehydrodieugenol, dehydrodivanillyl alcohol, dehydrodidihydroeugenol, dehydrodicreosol, magnolol and honokiol, respectively, were examined for their ability to inhibit UV-induced mutation in Salmonella typhimurium TA102. The relative mutagenic activities (RMA, %) indicated the mutation frequency of treated cells divided by the mutation frequency of control cells times 100%. The RMA (%) are as follows: 28 +/- 1, 31 +/- 1, 33 +/- 1, 41 +/- 2, 62 +/- 1, and 62 +/- 4 at concentrations of 5 micrograms per plate for dehydrodieugenol, dehydrodivanillyl alcohol, dehydrodidihydroeugenol, dehydrodicreosol, magnolol, and honokiol, respectively. These values indicate that low concentrations of these biphenyl compounds effectively suppress UV-induced mutagenesis. Also, these compounds acted as effective antimutagens in a dose-dependent manner (0.00005-5 micrograms per plate). These compounds are effective .OH scavengers. Consequently, the results obtained above suggest that these compounds could inhibit against UV-induced mutations by scavenging of .OH generated by UV irradiation. The results also suggest that .OH are associated with UV-induced mutation in Salmonella typhimurium TA102.

Biphenyl Compounds↗
PubMed2000

[Analysis of contact dermatitis by cytokines 4--Skin sensitization of biphenyl compounds].

Clove buds oil is one of very important natural essential oil with a typical spicy note and also known as a source of eugenol. These phenol compounds, which have the strong perfume of clove, are widely used not only as an analgesic and antiseptic agent in dentistry. However, the problem is that the phenol compounds caused sensitization on the skin occasionally. We reported that the skin sensitization by eugenol and its derivatives was detected in the guinea pig maximization test (GPMT) and also confirmed that dehydrodi-eugenol, a biphenyl compound of eugenol, did not show the skin sensitization. To discuss more, we examined the skin sensitization by several phenol compounds and its biphenyl ones. Consequently, we confirmed that the skin sensitization by biphenyl compounds more remarkably decreased than that by phenol compounds (monomer).

Animals↗
PubMed2001

[Direct optical resolution of the enantiomers of biphenyl compounds by high performance liquid chromatography on amylose tris-(3,5-dimethylphenylcarbamate) stationary phase].

A chiral stationary phase(CSP) was prepared by coating amylose tris-(3,5-dimethylphenylcarbamate) onto aminopropylated spherical silica gel. The enantioselective chromatographic separation of a series of biphenyl compounds with antihepatitis activity was performed for the first time on CSP. The effect of alcohol modifiers in mobile phase was investigated. The mobile phases used in the study were hexane modified by ethanol, 1-propanol, 1-butanol or 2-propanol. It was found that the retention times and the separation of the enantiomers of biphenyl compounds on the CSP were dramatically influenced by the nature of alcohols in the mobile phase, and the best alcohol modifier for some compounds was ethanol. The interaction between the stationary phase and samples was also discussed.

Amylose↗
PubMed1993

Effective inhibition of hydroxyl radicals by hydroxylated biphenyl compounds.

In aqueous media, approximate rate constants for the reactions between hydroxyl radicals (.OH) and biphenyl compounds such as dehydrodieugenol, magnolol, honokiol, dehydrodidihydroeugenol, dehydrodivanillyl alcohol, and dehydrodicreosol were estimated by competition reactions for .OH between these biphenyls and 5,5-dimethyl-1-pyrroline-N-oxide (DMPO). By measuring the decrease in the height of the EPR signals of the .OH spin adduct, rate constants in the order of 10(9) to 10(10) M were measured.

Biphenyl Compounds↗
PubMed1983

Effects of polychlorinated biphenyl compounds, 2,3,7,8-tetrachlorodibenzo-p-dioxin, phenobarbital and iron on hepatic uroporphyrinogen decarboxylase. Implications for the pathogenesis of porphyria.

Treatment of cultured chick embryo hepatocytes with phenobarbital, polychlorinated biphenyl compounds and 2,3,7,8-tetrachlorodibenzo-p-dioxin resulted in increased delta-aminolaevulinate synthase and decreased uroporphyrinogen decarboxylase activities and porphyrin accumulation; uroporphyrin and heptacarboxyporphyrin predominated. Iron had no effect on these changes. Simultaneous treatment of cultures with dioxin and phenobarbital produced a synergistic response in delta-aminolaevulinate synthase induction, uroporphyrinogen decarboxylase inhibition and porphyrin accumulation. These data suggest that an inhibitor of uroporphyrinogen decarboxylase may be generated in the liver from polychlorinated biphenyl compounds or dioxin by metabolic activation. Additionally these findings bear on the postulated role of these and related chemicals in determining the low levels of uroporphyrinogen decarboxylase activity in porphyria cutanea tarda patients.

5-Aminolevulinate Synthetase↗
PubMed1983

Ultrastructural features of the murine cutaneous microvasculature after exposure to polychlorinated biphenyl compounds (PCBs) and benzo-(a)-pyrene (BAP).

Exposure to polychlorinated biphenyl compounds (PCBs) has resulted in a variety of cutaneous effects in several species. When mice were exposed to PCBs through the diet and to benzo-(a)-pyrene (BAP) by topical application, hyperkeratinization occurred in the epidermis and hyperkeratinized cysts occasionally formed, but alterations were also observed in the dermis and in small cutaneous blood vessels, particularly capillaries and venules. The luminal borders of the endothelial cells often became irregularly ruffled, and pinocytotic vesicles increased in number and varied considerably in size. Subjacent to the endothelium and pericytes, the basal laminae were either replicated many times or extensively thickened. These effects were attributable to PCBs but not to BAP with the methods and dosages employed. Although endotheliocytosis has been reported in birds exposed to PCBs, vascular effects have not been previously described in mammals treated with these compounds.

Animals↗
PubMed2006

Tests of bioaccumulation models for polychlorinated biphenyl compounds: a study of young-of-the-year bluefish in the Hudson River estuary, USA.

A field-based study regarding uptake of polychlorinated biphenyl compounds (PCBs) by young-of-the-year (YOY) bluefish (Pomatomus saltatrix) was initiated to test a steady-state model of bioaccumulation and trophic transfer in a rapidly growing fish. Determination of prey composition as well as size-dependent growth and specific consumption rates for YOY bluefish from separate field and laboratory studies enabled the input of these species-specific parameters into the model. Furthermore, the time and duration of the exposure of YOY bluefish to dissolved PCBs from a well-characterized system (Hudson River, USA) was well known. Patterns of accumulation of individual PCB congeners differed relative to the accumulation of total PCBs, with the greatest net accumulation occurring for the higher-molecular-weight congeners. Comparison of lipid-normalized bioaccumulation factors (BAFs) with the octanol-water partition coefficients of individual PCB congeners revealed bluefish to be above the BAFs predicted by lipid-based equilibrium partitioning, suggesting that uptake from food is an important source of PCBs in YOY bluefish. Comparison of measured BAFs with values predicted by a steady-state, food-chain model showed good first-order agreement.

Animals↗
PubMed1984

Biological monitoring of workers exposed to polychlorinated biphenyl compounds in capacitor accidents.

For biological monitoring of workers exposed to polychlorinated biphenyl (PCB) compounds, a gas-chromatographic method for analysis of PCBs in serum was developed. The quantitation is performed with 15 pure isomers, and extraction and concentration factors are corrected with the aid of asymmetric PCB compounds added to each specimen. By this method, humans with no known occupational exposure to PCB compounds showed PCB levels in serum that were always less than 3 micrograms/l. Workers exposed in capacitor accidents have shown maximal concentrations close to 50 micrograms/l.

Accidents, Occupational↗
PubMed2001

Streptomyces aureofaciens sporulation-specific sigma factor sigma(rpoZ) directs expression of a gene encoding protein similar to hydrolases involved in degradation of the lignin-related biphenyl compounds.

A previously established method for the identification of promoters recognized by a heterologous RNA polymerase holoenzyme containing a particular sigma factor was used to identify promoters dependent upon a sporulation specific sigma factor, sigma(RpoZ), of Streptomyces aureofaciens. Three new positive DNA fragments were identified, and these putative rpoZ-dependent promoters, P(ren24), P(ren57), and P(ren71), contained sequences similar to the consensus sequence of flagellar and chemotaxis promoters. However, only P(ren71) was active in S. aureofaciens. The promoter was induced at the time of aerial mycelium formation, and was inactive in an S. aureofaciens strain with an rpoZ-disrupted gene. The results suggest that the P(ren71) promoter is recognized by an RNA polymerase holoenzyme containing sigma(RpoZ) in S. aureofaciens. Sequence analysis of the region directed by P(ren71) revealed a gene, ren71, encoding a protein of 358 amino acids with an Mr 37,770. The deduced protein product showed end-to-end sequence similarity to the meta-cleavage compound hydrolase of Sphingomonas paucimobilis.

Amino Acid Sequence↗
PubMed2000

Novel imidazolyl and triazolyl substituted biphenyl compounds: synthesis and evaluation as nonsteroidal inhibitors of human 17alpha-hydroxylase-C17, 20-lyase (P450 17).

The synthesis of a new series of P450 17 inhibitors is described. The imidazol-1-yl compounds 5 showed strong inhibition of P450 17 rat and especially human enzyme, the most active compounds being 5ax, 5ay and 5bx with IC50 values of 0.17, 0.24 and 0.25 microM, respectively (ketoconazole: 0.74 microM). The 1,2,4-triazol-1-yl compounds 6 were less active, while the 1,2,4-triazol-4-yl compounds 7 were inactive. The title compounds showed little inhibition of P450 arom. The most active P450 17 inhibitors 5ax and 5ay markedly decreased the testosterone plasma concentration of SD rats 2 h after application of 0.019 mmol/kg. After 6 h, 5ay still exhibited a strong effect.

Animals↗
PubMed1990

[Indoor air pollution by polychlorinated biphenyl compounds in permanently elastic sealants].

A common cause for indoor pollution by polycholorinated biphenyls (PCB) are defective capacitors of luminous discharge lamps. This paper describes elastic sealing compounds as another source of PCB pollution in buildings. In several rooms of a large school building indoor concentrations of 1000 ng PCB/m3 and more were registered. The total PCB concentration in sealing compounds ranged between 124,000 and 327,000 ppm. Blood specimens drawn from the school's personnel did not show elevated PCB concentrations, but additional incorporation of PCB via the respiratory tract cannot be excluded. We do not presume that any impairment of the health has been caused by this pollutant, but we think that reduction of the PCB indoor concentrations would be advisable for prophylactic purposes. Attention should be given to so-called open PCB systems such as elastic sealing compounds. Although they have been prohibited 1978, there might be a widespread use in older buildings.

Adult↗
PubMed1994

[Management of indoor air pollution by polychlorinated biphenyl compounds exemplified by two Hagen schools].

An indoor pollution of polychlorinated biphenyls (PCB) of about 4000 ng/m3 could be reduced by an average amount of 68% by temporary sealing of the primary source in combination with intensive cleaning. The costs were around DM 100,000.- for the school building containing 12 classrooms. Due to this procedure a continued usage of the building is possible until a concept of decontamination is available. In another building the PCB indoor pollution was reduced by 73% in a representative trial restoration, whereas the stripping of the paint with a chemical caustic substance induced a significant reduction of the PCB concentration. The usage of special air conditioners--called "Luftwäscher"--in the classrooms did not reduce the PCB concentration. The realisation of disturbing factors such as the fluctuation of the temperature is of great importance for judging the efficiency of decontamination procedures. The possible misinterpretation regarding the results and the data of decontamination procedures can be excluded by parallel measurements in control rooms. Costs induced by these additional analyses will be reduced by the early realization of ineffective steps.

Adolescent↗
PubMed2003

Quantitative structure-biodegradation relationships for ortho-substituted biphenyl compounds oxidized by Methylosinus trichosporium OB3b.

Methanotrophs, bacteria that thrive in the presence of stable methane and oxygen concentrations, can cometabolically oxidize ortho-substituted biphenyls to yield a variety of hydroxylated products. Despite awareness of the susceptibility of ortho-substituted biphenyls and other aromatic compounds to methanotrophic oxidation, the molecular properties relevant for predicting rates of methanotrophic oxidation are unknown. To this end, we have developed quantitative structure-biodegradation relationships using oxygen uptake activity by the type 2 methanotroph. Methylosinus trichosporium OB3b, expressing the soluble form of methane monooxygenase and in the presence of nine ortho-substituted biphenyls. Multivariate analysis yielded the strongest correlations using the initial slope of the oxygen uptake rate versus substrate concentration curve as the dependent variable. Quantum mechanical descriptors, including the sum of carbon charges on the substituted ring, the charge on the substituted carbon, and the width of compound calculated using computationally derived bond lengths and dihedral angles, correlated more strongly with oxygen uptake activity than did empirically derived electronic descriptors. The resulting models suggest a significant influence of substituent electronic nature and size and the involvement of the substituted carbon site in the oxidation of these compounds by M. trichosporium OB3b.

Biodegradation, Environmental↗