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At least 19 recordsLinked to original sources
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↗
PubMed1975

[Organochlorine pesticide (DDT etc.) and polychlorinated biphenyl (PCB) compound residues in human milk (from the area of Vienna and lower Austria) (author's transl].

31 samples of human milk (Vienna and Lower Austria) were examined for the presence of organochlorine pesticide and polychlorinated biphenyl (PCB) compound residues using standard methods. In Viennese samples, mean concentrations of these residues in the milk fat were as follows: HCB 1.24 ppm, gamma-HCH 0.048 ppm, beta-HCH 0.20 ppm, DDE 3.38 ppm, DDT 1.06 ppm and PCB compounds 1.54 ppm. The mean levels of these substances in the milk fat samples from women living in the area of Mistelbach, Lower Austria, were: HCB 3.67 ppm, gamma-HCH 0.063 ppm, beta-HCH 0.28 ppm, DDE 3.92 ppm, DDT 1.76 ppm and PCB compounds 1.29 ppm. The difference between the content of HBC residues in milk samples from the city and from an intensively agricultural area is significant. The results are compared with figures from other countries. With the mother's milk the baby consumes a quantity of pesticides which is very often larger than the acceptable daily intake.

Chromatography, Gas↗
PubMed1991

Conformationally restricted polysubstituted biphenyl derivatives with angiotensin II receptors antagonist properties.

The synthesis and in vitro activity of new nonpeptide angiotensin II antagonists is presented. Compared to previously reported biphenyl compounds, the new analogues 8 and 9 have reduced conformational freedom derived from steric hindrance. Methyl 4'-methyl-2',6'-dimethoxy[1,1'-biphenyl]-2-carboxylate 4 has been synthesized by a Von Pechmann condensation of orcinol with oxocyclohexane-2-carboxylate followed by dehydrogenation. This scheme provided the carbon skeleton of the biphenyl potentially substituted on the 2-, 2'-, 4'-, and 6'-positions. Elaboration of the subsituents led to a biphenyl derivative used to alkylate a 2-n-butyl-4-chloro-5-(hydroxymethyl)imidazole. After coupling with the imidazole two regioisomers were separated and identified by 1H NMR. NOESY experiments were useful to establish regiochemistry of the final products that have angiotensin II blocking activity. Their affinity for angiotensin II receptors was established in a binding assay experiment and in an isolated organ test. The presence of 2',6'-dimethoxy substituent on the biphenyl moiety of the antagonist was found to significantly decrease affinity for the receptor.

Angiotensin II↗
PubMed1992

The in vivo and in vitro genotoxicity of aromatic amines in relationship to the genotoxicity of benzidine.

Benzidine and 12 related aromatic amines have been studied for the effects of substituent groups and pi orbital conjugation on their genotoxicity as measured by their mutagenicity in vitro with Salmonella and by chromosomal aberrations (CA) in vivo in the bone-marrow cells of mice. The in vitro studies indicated increases in mutagenicity with increases in the electron withdrawing ability of para' substituents. Mutagenicity also increases with increased conjugation as shown by the degree of planarity of the biphenyl compounds and by comparing the mutagenicities of biphenyl amines to stilbenes as well as to ethylene bridged diphenyl compounds. The relative in vitro mutagenicity results were not predictive of relative in vivo CA results. The 3 most genotoxic compounds in vivo were the conjugated amines without substituents in the para' position. The CA values for 4-aminostilbene were exceptionally high. These in vivo results indicate increased genotoxicity for benzidine analogs without substitution in the para' position.

Aminobiphenyl Compounds↗
PubMed1989

Teratogenicity of three substituted 4-biphenyls in the rat as a result of the chemical breakdown and possible metabolism of a thromboxane A2-receptor blocker.

AH23848 is a potent thromboxane A2-receptor blocker inhibiting platelet aggregation in vitro and in vivo. Oral administration to pregnant rats during days 7-16 of pregnancy, at doses of 0, 10, 45, or 200 mg/kg twice daily, resulted in dose-related maternal, embryonic, and fetal toxicity. The most notable observation was herniation of the diaphragm occurring in 1.5 and 100.0% of fetuses at the 45 and 200 mg/kg doses, respectively, when examined at term. A further study at 150 mg/kg twice daily during days 7-16, 7-11, or 12-16 of pregnancy revealed incidences of diaphragmatic hernia up to 42%. Herniation varied from small areas of eventration of membranous diaphragm to fetuses with apparent total absence of the diaphragm. The positions of the hernias in the diaphragm, following dosing over varying periods of organogenesis, reflected the chronology of diaphragm formation in the rat. The teratology of AH23848 was unrelated to its thromboxane A2-receptor blocker properties but was related to a chemical breakdown product, 4-biphenylmethanol. Some substituted biphenyl compounds appear to be specific teratogens in the rat, with their effects targeted at the developing diaphragm. A possible mechanism of herniation is the interference with muscularisation of the membranous diaphragm, resulting in weakness and perforation.

Administration, Oral↗
PubMed1991

Workshop on human health impacts of halogenated biphenyls and related compounds.

A workshop on the Human Health Impacts of Halogenated Biphenyls and Related Compounds was held to assess the state of current research on these chemicals and to make recommendations for future studies. Participants discussed results from laboratory animal experiments on PCBs, PBBs, dioxins, and dibenzofurans which demonstrate a common mode of toxicological action while also revealing large variations in toxicological potency both within and between these chemical families. These variations demonstrate the importance of congener-specific analyses in future studies of effects of exposure to these compounds. Results from epidemiological studies of environmentally exposed adult and pediatric populations from the U.S., Japan, and Taiwan and occupationally exposed cohorts from around the world were considered. It was concluded that available evidence did not demonstrate serious adverse effects such as cancer, in exposed adult cohorts but did provide indications of possible neurobehavioral effects in children exposed in utero. In addition, workshop participants described newly developed markers of exposure and techniques for assessing endocrinological, immunological, and neurological effects and suggested these be applied to epidemiological studies of the effects of polyhalogenated compounds. Other recommendations included identification of other cohorts and development of a large registry of exposed individuals; performance of detailed studies of reproductive function and outcomes in exposed populations; and follow up of neurobehavioral effects in offspring of exposed women.

Biphenyl Compounds↗
PubMed1992

Specific binding of polychlorinated biphenyls to rat liver cytosol protein.

Specific binding of polychlorinated biphenyls (PCBs) to rat liver cytosol protein has been detected using the 3H-labeled PCB probe 2,2',4,4',5,5'-hexachlorobiphenyl (6-CB). Binding of 6-CB to cytosol protein is displaced by its non-radioactive congener, is of high affinity (Kd approximately 3 nM) and is saturable (maximal binding capacity Bmax approximately 600 pmol/mg protein). 6-CB binding is not found in liver cytosol of animals fed a PCB-supplemented diet (500 ppm PCB for 5 days). Binding is also in vitro inhibited by high concentrations of triglyceride. PCB congeners such as 3,3',4,4',5-pentachlorobiphenyl as well as the thyroid hormones 3,5,3',5'-tetraiodothyronine and 3,5,3'-triiodothyronine (the latter hormone with an order of magnitude lower affinity) compete for the PCB binding site. On the other hand, a number of biochemically important compounds including the PCB core compound biphenyl and the hormone ligands dexamethasone and estradiol, as well as 2,3,7,8-tetrachlorodibenzo-p-dioxin, do not compete for the 6-CB binding site. The data provide the first evidence of specific binding of unmetabolized PCB congeners to distinct binding sites in rat liver cytosol.

Animals↗