Polycyclic aromatic hydrocarbons in placenta

Concentrations of chrysene, benz [a] anthracene, benzo [a]-pyrene, benzo [b] fluoranthene, indeno [1,2,3-c,d] pyrene, dibenz [a,h] anthracene, and benzo [g,h,i] perylene were measured in placentas from 200 women from two cities in Ukraine, Kyiv and Dniprodzerzhinsk. The participants had no special exposures and were chosen from among subjects in an ongoing study of reproductive health. All seven of the polycyclic aromatic hydrocarbons (PAHs) were found in all placentas, with the sole exception of benzo [a] pyrene in one placenta. Chrysene was present at the highest concentrations, with median 1.38 ng/g dry weight. Dibenz [a,h] anthracene and benzo [g,h,i] perylene had the lowest concentrations; each had median 0.73 ng/g dry weight. Concentrations in Kyiv were slightly higher than those in Dniprodzerzhinsk, but the difference was significant only for dibenz [a,h] anthracene. Dibenz [a,h] anthracene and benzo [g,h,i] perylene increased significantly with maternal body mass index, but other PAHs showed no such pattern. Placentas from deliveries in autumn or winter had slightly but not significantly higher concentrations. Concentrations were not related to maternal age. There were too few smokers in the sample for meaningful evaluation. No associations were seen between any of the placental PAH concentrations and birth weight of the infant.     

Polycyclic aromatic hydrocarbons in commercial solvents

Samples of benzene, hexane, isooctane, and toluene were examined by adsorption and partition chromatography, followed by spectroscopic analysis of the fractions. Several polycyclic aromatic hydrocarbons were identified in all the samples. One sample of hexane contained significant concentrations of benzo[a]pyrene and benz[a]anthracene, in addition to other compounds.     

Induction of intestinal microsomal enzymes by polycyclic aromatic hydrocarbons

1. The efficacy of induction of intestinal microsomal aryl hydrocarbon hydroxylase (AHH), 7-ethoxyresorufin o-deethylase and cytochrome P-450 by various polycyclic aromatic hydrocarbons were studied. 2. The greatest induction of the specific MFO activities tested was produced by 2,3,7,8-tetra-chlorodibenzo-p-dioxin (TCDD) with 3-methyl-cholanthrene (MC) a close second. 3. Rank order of efficacy of induction of spectrally determined cytochrome P-450 was 2,3,7,8-tetra-chlorodibenzo-p-dioxin (TCDD), Arochlor 1254 (ARO), 3-methylcholanthrene (MC) and benz(a)anthracene(BA). 4. No unique protein peaks were found when the sodium dodecyl sulfate-polyacrylamide gel electrophoresis of MC treated intestinal microsomes were prepared.     

Comparative aquatic toxicology of aromatic hydrocarbons

Structure-toxicity relationships were investigated for six organic contaminants, representative of three chemical classes, likely to be found in coal conversion process waters and effluents. Using embryo-larval stages of the rainbow trout (Salmo gairdneri) and largemouth bass (Micropterus salmoides), continuous-flow toxicity tests were performed on hydroxylated aromatic hydrocarbons (phenol, β-naphthol), azaarenes (quinoline, acridine), and polycyclic aromatic hydrocarbons (naphthalene, phenanthrene). Exposure was initiated at fertilization and maintained through 4 days posthatching. Median lethal concentrations (LC₅₀), based on combined frequencies of embryo-larval mortality and teratogenesis, were used to rank the toxicity of the compounds to each fish species. With the trout, the order of decreasing toxicity was phenanthrene (0.04 mg/L), β-naphthol (0.07 mg/L), naphthalene (0.11 mg/L), phenol (0.15 mg/L), acridine (0.32 mg/L) and quinoline (11.0 mg/L). The toxicological ranking with the bass was phenanthrene (0.18 mg/L), naphthalene (0.51 mg/L), acridine (1.02 mg/L), β-naphthol (1.77 mg/L), phenol (2.80 mg/L) and quinoline (7.50 mg/L). For each class of compounds, the chemical with the greater number of aromatic rings always exerted the greater toxicity. In tests with both fish species, β-naphthol (two rings) was about twice as toxic as phenol (one ring), and phenanthrene (three rings) was nearly three times more toxic than naphthalene (two rings). Acridine (three rings) was seven times more toxic to bass and 34 times more toxic to trout than was quinoline (two rings). This relationship between ring number and toxicity was in excellent agreement with results from acute tests on the same compounds. Furthermore, a close correlation existed between toxicity and n-octanol:water partition coefficients within each class of compounds.     

Morphology of oocyte and follicle destruction by polycyclic aromatic hydrocarbons in mice

The carcinogenic polycyclic aromatic hydrocarbons, benzo(a)pyrene, 3-methylcholanthrene, and 7,12-dimethylbenz(a)anthracene, destroy primordial oocytes in the mouse ovary. The rate of oocyte destruction was proportional to the activity of the ovarian microsomal cytochrome P-450-dependent monooxygenase, aryl hydrocarbon (benzo(a)pyrene) hydroxylase (EC 1.14.14.2) as well as to the carcinogenicity of the polycyclic hydrocarbon. After treatment with benzo(a)pyrene or 3-methylcholanthrene only primordial oocyte destruction occurred, and no evidence of toxicity was observed in surrounding granulosa or ovarian stromal cells. 7,12-Dimethylbenz(a)anthracene was much more toxic and destroyed large follicles and oocytes in addition to primordial oocytes and primary follicles. Seven weeks after treatment with 3-methylcholanthrene the ovary had the bland afollicular appearance characteristic of ovarian failure. These three polycyclic aromatic hydrocarbons are capable of producing premature ovarian failure in rodents.     

Development and modification of a recombinant cell bioassay to directly detect halogenated and polycyclic aromatic hydrocarbons in serum.

Polycyclic and halogenated aromatic hydrocarbons (PAHs/HAHs) are a diverse group of widespread and persistent environmental contaminants that can cause a variety of detrimental effects in vertebrates. As most available methods to detect these contaminants are expensive, labor and time intensive, and require large amounts of tissue for extraction and analysis, several rapid mechanistically based bioassay systems have been developed to detect these chemicals. Here we describe application and optimization of a recently developed recombinant mouse cell bioassay system that responds to both PAHs and HAHs with the rapid induction of firefly luciferase for the detection of these chemicals in whole serum samples. This chemically activated luciferase expression (CALUX) bioassay has been modified to allow rapid (4-h) and direct analysis of small volumes (25-50 microl) of whole serum in a 96-well microtiter plate format without the need for solvent extraction. This bioassay can detect as little as 10 parts per trillion of the most potent HAH, 2,3,7,8-TCDD, and is also sensitive to other HAHs and PAHs. The use of simple procedures corrects for interplate and intraplate variability and the Ah receptor dependence of the induction response is accounted for by use of the antagonist 4-amino-3-methoxyflavone.     

Structure-acute toxicity relationship of aromatic hydrocarbons in mice

The structure-acute toxicity relationship of aromatic hydrocarbons was examined in mice. In all test compounds, the acute toxicity was determined under 2 conditions: control LD₅₀ (LD₅₀-cont) and carbon tetrachloride (CCl₄)-pretreated LD₅₀ (LD₅₀-CCl₄). The CCl₄-pretreatment was done in order to evaluate the toxic potency of compound itself without the influence of metabolism. Both log (1/LD₅₀-cont) and log (1/LD₅₀-CCl₄) were functions of the log P, n-octanol/water partition coefficient, i.e., log (1/LD₅₀-cont) = 0.080 log P − 1.532 and log (1/LD₅₀-CCl₄) = −0.040(log P)² + 0.157 log P − 1.373. Both equations were statistically significant (P < 0.01). The ratio of LD₅₀-cont/LD₅₀-CCl₄ indicated that metabolic activation is more evident in hydrophobic compounds than in hydrophilic compounds. The results suggest that hydrophobicity of the aromatic hydrocarbons plays an important role in determining their acute toxicity.     

Polycyclic aromatic hydrocarbons in traditional medicinal preparations.

Ayurvedic medicinal preparations, commonly known as bhasmas, were analysed for the determination of polycyclic aromatic hydrocarbons (PAH). All the preparations contained PAH. The level of total PAH varied widely (2.32-9.55 ppm) among the preparations tested. Similarly, the benzo(a)pyrene level also varied the highest concentration being 9.7 ppm.     

Alterations in central monoaminergic neurotransmission induced by polycyclic aromatic hydrocarbons in rats.

Benzo[alpha]pyrene (B[a]P) is a product derived from incomplete combustion of organic material and is considered responsible for chemically-induced cancer in humans. In the present study, the levels of noradrenaline (NA), dopamine (DA), dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), 5-hydroxytryptamine (5-HT), and 5-hydroxyindoleacetic acid (5-HIAA) were measured in the brains of female Wistar rats 6, 12, 24 and 96 h after a single dose of B[alpha]P (50 mg kg(-1) b.w., i.p.), and also after repeated administration of B[alpha]P (50 mg kg(-1) b.w., i.p., 2 x wk, 1 mo). The brain regions studied were the striatum, hypothalamus, midbrain and cortex. Catecholamines were measured using high performance liquid chromatography (HPLC) and electrochemical detection. Significant changes were observed in the striatum where NA, DA, DOPAC were decreased after 24 h and HVA was decreased after 6 h. In contrast, no major alterations occurred in 5-HT and 5- HIAA. In the hypothalamus, a significant decrease in NA was observed after 96 h. In the midbrain, the most important change observed was the decrease in NA after 24 h. A trend toward an increase in 5-HIAA was observed in the cortex after 6 h. The results demonstrate that B[alpha]P induces alterations in the dopaminergic and serotoninergic systems throughout the brain. These alterations may lead to behavioural and hormonal disturbances.     

Microbial degradation of polycyclic aromatic hydrocarbons and polycyclic aromatic nitrogen heterocyclics

Fermentor studies were conducted to examine the microbial degradation of polycyclic aromatic hydrocarbons (PAHs; naphthalene, phenanthrene, anthracene) and a polycyclic aromatic nitrogen heterocyclic (quinoline) using a mixed bacterial culture capable of utilizing these compounds as the sole carbon and energy source for growth. Half-lives for the three PAHs in the cyclone fermentor system ranged from 1 day for naphthalene to 4 days for anthracene. Several major metabolites during the biodegradation of PAHs were also identified. These included 2-hydroxybenzoic acid and 1-naphthalenol (for naphthalene); 1-phenanthrenol and 1-hydroxy-2-naphthalenecarboxylic acid (for phenanthrene); and 3-hydroxy-2-naphthalenecarboxylic acid (for anthracene). Thus our bacterial culture biodegraded the three PAHs by initial hydroxylation of the molecule followed by the eventual cleavage of the ring to yield the ortho- or meta-cleavage intermediates, which would be further metabolized via conventional metabolic pathways. However, biodegradation of the nitrogen-containing polycyclic aromatic hydrocarbon compound quinoline by our culture resulted in the accumulation of 4–5 metabolites, one of which has been identified as 2-quinolinol. Work is in progress to identify the other metabolites from quinoline degradation. © 1992 John Wiley & sons, Inc.     

Protein tyrosine kinase activation by polycyclic aromatic hydrocarbons in human HPB-ALL T cells

It has been well established that certain polycyclic aromatic hydrocarbons (PAHs), such as 7,12-dimethylbenz[a]anthracene (DMBA), 3-methylcholanthrene (3MC), and benzo[a]pyrene (BaP), produce immunotoxicity and cancer in rodents and that these effects are also likely seen in humans. Our laboratory has found that polycyclic aromatic hydrocarbons (PAHs) produce an increase in intracellular Ca2+ in lymphocytes that appears to correlate with their immunotoxicity. Specifically, immunotoxic PAHs, such as DMBA and BaP, have been shown to produce a sustained increase in intracellular Ca2+ in lymphocytes, whereas nonimmunosuppressive PAHs, such as benzo[e]pyrene (BeP) and anthracene, do not. Our studies previously demonstrated that the rapid increase in intracellular Ca2+ produced by DMBA in HPB-ALL T cells was caused by protein tyrosine kinase (PTK) activation in human T cells, leading to tyrosine phosphorylation of phospholipase C (PLCgamma) and IP3-dependent Ca2+ mobilization. However, the specificity of PTK activation by PAHs was not established. In the present studies, we extend our observations of PTK activation by examining a number of PAHs for their effects on total and specific (Fyn and ZAP-70) PTK activity. We show that 10 microM concentrations of PAHs nonspecifically and rapidly (within 5 min) stimulate PTKs in the HPB-ALL human T cell line. BeP and anthracene were found to be nearly as effective at increasing total tyrosine kinase activity as DMBA, 3MC, and BaP, observed 5 min after exposure. We found that only immunotoxic PAHs activated the Fyn and ZAP-70 PTKs at 10 min, but total PTK activity was still increased by nonimmunotoxic PAHs, BeP, or anthracene after 10 min of exposure. These studies demonstrate that immunotoxic PAHs increase total and specific PTK activity in the human HPB-ALL T cell line. Thus the rapid increase in PTK activity produced by PAHs may not correlate with the immunotoxicity of these agents.     

GC-MS法测定盐酸金霉素眼膏中16种多环芳烃含量

目的 建立盐酸金霉素眼膏中16种多环芳烃(PAHs)的气相色谱-质谱含量测定方法。方法 盐酸金霉素眼膏经正己烷溶解后，用正己烷饱和乙腈多次萃取，浓缩后经GC-MS法检测，气相色谱采用DB-5MS毛细管柱，程序升温，进样口温度250℃，质谱采用电子轰击(EI)离子源，以选择反应监测(SIM)模式进行检测。同时从辅料来源及生产工艺上分析制剂中PAHs异常的主要原因。结果 16种PAHs在相应浓度范围内线性关系良好，定量限(LOQ)为0.3~20.0ng/mL，回收率为72%~118%，相对标准偏差(RSD)均小于2.5%，辅料凡士林的质量直接影响制剂的好坏。结论 本法准确度高、灵敏度强，适用于盐酸金霉素眼膏中PAHs的检测，可为眼膏剂的质量控制与安全性评估提供数据参考。     

Induction of mixed-function oxidase activity in mouse lymphoid tissues by polycyclic aromatic hydrocarbons

Polycyclic aromatic hydrocarbon (PAH) exposure can cause mixed-function oxidase (MFO) enzyme induction in certain tissues of various organisms. Measurement of such induction might serve as a useful bioindicator of human exposure to PAHs, provided readily obtainable human tissues can be utilized for such measurements. We have investigated the MFO activity in various lymphoid tissues of the C3H mouse as a model system and have studied the effect of systemic PAH treatment on such enzyme activity. An MFO enzyme assay was used to measure the activity of 7-ethoxyresorufin deethylase, an enzyme activity that may be specific for the cytochrome P-448 subset of MFO enzymes (those enzymes that are induced in cells or tissues following PAH administration). Intraperitoneal injection of mice with 180 mg/kg (4.6 mg) benzo[a]pyrene (BaP) or 160 mg/kg (4.0 mg) 3-methylcholanthrene (MC) produced a significant induction in MFO activity in mouse spleen S9 fractions 48 h after the injection. Induction ratios (induced activity/control activity) between 4 and 5 were seen with BaP; MC produced induction ratios of 2.5-3.0. Enzyme activity was not induced in the spleen within 16 h following BaP or MC administration. Other experiments indicated that MFO activity could be induced in thymus cells 48 h after either BaP or MC treatment. Treatment with BaP or MC did produce significant enzyme induction in the liver and lung tissues from the animals both 16 and 48 h after chemical treatment.     

Antagonistic interactions among nephrotoxic polycyclic aromatic hydrocarbons

Although the liver and pulmonary toxicity of polycyclic aromatic hydrocarbons (PAHs) has been extensively characterized, limited data concerning the nephrotoxic potential of these chemicals are available. The present studies were conducted to define the kidney cell-specific toxic responses to anthracene (ANTH), benzo[a]pyrene (BaP), and chrysene (CHRY). Given that exposure to environmental chemicals from a specific source is rarely limited to a single compound, a second goal was to evaluate the nephrotoxic potential of binary and ternary mixtures of these chemicals. Cultured rat glomerular mesangial cells (rGMCs) and porcine cortico-tubular epithelial kidney cells (LLCPK-1) were challenged with hydrocarbon concentrations ranging from 0.03 to 30 microM for up to 24 h and were processed for measurements of mitochondrial membrane permeability, trypan blue dye exclusion, cytoplasmic enzyme leakage, and protein synthesis. BaP induced a threefold increase in mitochondrial fragility, a modest increase in cellular death, and 40% decrease in the rate of protein synthesis in rGMCs. Anthracene was also cytotoxic to rGMCs, inducing a twofold increase in mitochondrial fragility and a 40% decrease in the rate of protein synthesis, but no changes in cellular viability. Although CHRY was devoid of toxicity to rGMCs, a 40% decrease in the rate of protein synthesis was observed in LLCPK-1 cells treated with this hydrocarbon. BaP and ANTH were not overtly cytotoxic to LLCPK-1 cells at any of the concentrations tested. Binary and ternary mixtures of BaP with ANTH and CHRY in rGMCs, and mixtures of CHRY with ANTH and BaP in LLCPK-1 cells, yielded antagonistic interactions. Based on these data, it is concluded that PAHs exhibit chemical- and cell-specific nephrotoxicity, but that toxicological outcomes are influenced by the presence of multiple hydrocarbons in complex mixtures.