Instruct: Given a question, retrieve passages that answer the question.
Query: polycyclic hydrocarbons
Vegetarian diets are rich in antioxidant phytochemicals. However, they may not act as antioxidants in vivo, and yet still have important signaling and regulatory functions. Some may act as pro-oxidants, modulating cellular redox tone and oxidizing redox sensitive sites. In this review, evidence for health benefits of vegetarian diets is presented from different perspectives: epidemiological, biomarker, evolutionary, and public health, as well as antioxidant. From the perspective of molecular connections between diet and health, evidence of a role for plasma ascorbic acid as a biomarker for future disease risk is presented. Basic concepts of redox-based cell signaling are presented, and effects of antioxidant phytochemicals on signaling, especially via redox tone, sulfur switches and the Antioxidant Response Element (ARE), are explored. Sufficient scientific evidence exists for public health policy to promote a plant-rich diet for health promotion. This does not need to wait for science to provide all the answers as to why and how. However, action and interplay of dietary antioxidants in the nonequilibrium systems that control redox balance, cell signaling, and cell function provide rich ground for research to advance understanding of orthomolecular nutrition and provide science-based evidence to advance public health in our aging population.
Objective To test the effect of four polychlorinated biphenyl congeners (PCB-77, PCB-105, PCB 153 and PCB 180) on expression of three adhesion markers, TGF-β1, VEGF, and type I collagen in normal human peritoneal and adhesion fibroblasts Design Cell culture study Settings University Research Laboratory Patients Primary cultures of normal peritoneal and adhesion fibroblasts were established from three patients. Interventions Fibroblasts were treated with PCB-77, PCB-105, PCB-153 or PCB-180, 20 ppm for 24 hours. Total RNA was extracted from each treatment and subjected to real-time RT/PCR. Main Outcome and Measures mRNA levels of type I collagen, VEGF and TGF-β1. Results Normal human peritoneal fibroblasts expressed type I collagen, VEGF and TGF-β1. Exposure of normal human fibroblasts to PCB-77, PCB-105, PCB-153 or PCB-180 did not affect mRNA levels of β-actin, the house keeping gene used to normalized RNA levels for the real-time RT/PCR, nor did it affect cell viability as assessed by trypan blue exclusion. PCB treatments, compared to control, resulted in no significant change for TGF-β1 or VEGF mRNA levels, in normal peritoneal and adhesion fibroblasts. In marked contrast, type I collagen mRNA levels were markedly increased in response to the brief 24 hrs exposure to each PCB, treatment each (P<0.0001) in both cell types. Conclusion The finding that PCB-77, PCB-105, PCB-153 or PCB-180 increased the expression of type I collagen in human normal peritoneal and adhesion fibroblasts is the first demonstration of involvement of organochlorines in the pathogenesis of tissue fibrosis. This may implicate organochlorine exposure as an etiologic factor in a wide variety of previously unlinked human ailments characterized by fibrosis.
One combined catfish feed sample from Arkansas, USA, and its eight ingredients were analyzed for PCDDs and PCDFs. One of the ingredients, soybean meal, was highly contaminated by PCDDs, especially the toxic 2,3,7,8-substituted congeners, e.g., 7.3 pg/g dry weight or 370 pg/g lipid for the 2,3,7,8-tetra CDD. The I-TEQ value for the soybean meal was 11.4 pg/g dry weight or 576 pg/g fat. The corresponding values for the combined catfish feed concentrations were approximately 3 times lower. The congener pattern, the congener profile and the ratio sigma PCDDs/sigma PCDFs for the soybean meal were quite unique. We are not aware of any environmental sample or technical product with similar characteristics. As a result, natural formation of the PCDDs found in the soybean meal cannot be ruled out.
Smoked foods including turkey, pork, chicken, beef and fish products were screened for the presence of carcinogenic and non-carcinogenic polycyclic aromatic hydrocarbons (PAHs). Eighteen commercial liquid smoke flavourings and seasonings were also analysed. Total PAH concentrations in smoked meat products ranged from 2.6 micrograms/kg in a cooked ham sample to 29.8 micrograms/kg in grilled pork chops, while those in fish products ranged from 9.3 micrograms/kg in smoked shrimp to 86.6 micrograms/kg in smoked salmon. Total concentrations of the carcinogenic PAHs (benzo[a]anthracene, benzo[b]fluoranthene, benzo[a]pyrene, dibenzo[a,h]anthracene, and indeno[1,2,3-c,d]pyrene) ranged from non-detectable in several meat products to 7.4 micrograms/kg in grilled pork chops, and from 0.2 micrograms/kg in trout to 16.0 micrograms/kg in salmon. In liquid smoke flavourings and seasonings, total PAH concentrations ranged from 6.3 to 43.7 micrograms/kg, with the carcinogenic PAHs ranging from 0.3 to 10.2 micrograms/kg.
In our laboratories, for several years, two phenolic compounds have been detected during gas chromatographic-mass spectrometric analysis of urinary steroid extracts from human and animal species. Although features of the mass spectra of their trimethylsilyl (TMS) ether derivatives resembled those of oestrogens, they were atypical of steroids. The possibility that they were artefacts of the isolation procedures was discounted after careful studies with blanks, by varying the extraction method and because they were present almost exclusively as conjugates of glucuronic acid. Several of the general characteristics of the unknown compounds were reported after one (referred to as compound 180/442) was found to have a cyclic pattern of excretion during the menstrual cycle of an adult vervet monkey (Fig. 1). An investigation of the nature and distribution of the compounds has shown them to be urinary constituents in humans, baboons, vervet monkeys and rats, and further related compounds have been detected, so far only in vervet monkey urine. We now report spectroscopic and chemical studies that show the two original compounds to be lignans, which have a 2,3-dibenzylbutane skeleton as their basic structure. Unlike all previously known natural lignans, invariably of plant origin, the two mammalian compounds carry phenolic hydroxy groups only in the meta position of the aromatic rings.
The exposure to some chemicals can lead to hormone disrupting effects. Presently, much attention is focused on so-called xeno-estrogens, synthetic compounds that interact with hormone receptors causing a number of reactions that eventually lead to effects related to reproduction and development. The current study was initiated to investigate the presence of a number of such compounds in precipitation as a follow-up on a previous study in which pesticide concentrations in air and precipitation were determined. Rainwater samples were collected at about 50 locations in The Netherlands in a four week period. The samples were analysed for bisphenol-A, alkylphenols and alkylphenol ethoxylates, phthalates, flame retardants and synthetic musk compounds. The results clearly indicated the presence of these compounds in precipitation. The concentrations ranged from the low ng l(-1) range for flame retardants to several thousands of ng l(-1) for the phthalates. Bisphenol-A was found in 30% of the samples in concentrations up to 130 ng l(-1), while alkylphenols and alkylphenol ethoxylates were found in virtually all locations in concentrations up to 920 ng l(-1) for the individual compounds. Phthalates were by far the most abundant xeno-estrogens in the precipitation samples and were found in every sample. Di-isodecyl phthalate was found in a surprisingly high concentration of almost 100 000 ng l(-1). Polybrominated flame retardants were found in the low ng l(-1) range and generally in less than 20% of the samples. Noticeable was the finding of hexabromocyclododecane, a replacement for the polybrominted diphenyl ethers at one location in a concentration of almost 2000 ng l(-1). Finally, as expected, synthetic musk compounds were detected in almost all samples. This is especially true for the polycyclic musks HHCB and AHTN. Nitro musks were found, but only on a few locations. Kriging techniques were used to calculate precipitation concentrations in between actual sampling locations to produce contour plots for a number of compounds. These plots clearly show located emission sources for a number of compounds such as bisphenol-A, nonylphenol ethoxylate, phthalates and AHTN. On the contrary, the results for HHCB and some phthalates indicated diffuse emission patterns, probably as the result of the use of consumer products containing these compounds.
Nine catfish fillets, three catfish nuggets, two feed samples, and one pond sediment were analyzed for PCDD, PCDF, and PCB. Farm-raised catfish from Mississippi, Alabama, and Arkansas contained significant levels of 2,3,7,8-substituted PCDD and PCDF. In addition, a large number of non-2,3,7,8-substituted congeners were present in all samples. The catfish fillets and catfish nuggets also contained high concentrations of dioxin-like PCB, as well as a number of non-dioxin-like PCB. The TEQ based on PCDD and PCDF ranged from 9.5 to 43.0 pg/g lipid and the TEQ based on PCB ranged from 0.45 to 4.9 pg/g lipid for all catfish samples. The dioxin-like PCB contributed 4-16% to the total TEQ (PCDD/PCDF/PCB) for the catfish samples. The major source for the PCDD, PCDF, and PCB appears to be from feed and not from pond sediment. Immunoreactive CYP1A protein was elevated 2.5 fold in the pond-raised catfish compared to the aquarium-raised one. The results of this study suggest that the PCDD/PCDF are more important than the PCB in the CYP1A induction.
A facile method was established to measure heterocyclic aromatic amines (HAAs) accumulated in human hair and rodent fur. The samples were digested by base hydrolysis, and the liberated HAAs were isolated by tandem solvent/solid-phase extraction. Quantification was done by liquid chromatography/tandem mass spectrometry, using a triple stage quadrupole mass spectrometer in the selected reaction monitoring mode. In a pilot study of 12 human volunteers, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) was detected in hair of six meat-eaters at levels ranging from 290 to 890 pg/g hair. 2-Amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) and 2-amino-9H-pyrido[2,3-b]indole (AαC) were below the limit of quantification (LOQ) (50 pg/g hair) in hair from meat-eaters and six vegetarians. PhIP was detected in the hair from one vegetarian, and at level just above the LOQ (65 pg/g hair), indicating PhIP exposure occurs primarily through meat consumption. The levels of PhIP in hair samples from two meat-eaters varied by less than 24% over a 6-month interval, signifying that the exposure to PhIP and its accumulation in hair are relatively constant over time. In a controlled feeding study, female C57BL/6 mice were given these HAAs in their drinking water for 1 month, at six daily dose concentrations ranging from 0, 0.080 to 800 µg/kg body weight. PhIP was detected in fur of mice at all doses, whereas AαC and MeIQx were detected in fur at dosages ≥0.8 µg AαC/kg body weight and ≥8 µg MeIQx/kg body weight. There was a strong positive relationship between dosage and each of the HAAs accumulated in fur and their DNA adducts formed in liver and colon (p-values <0.0001); however, the levels of HAA in fur did not correlate to the levels of DNA adducts after adjustment of dose. Thus, hair appears to be a promising long-lived biomarker with by which we can assess the exposure to PhIP, a potential human carcinogen.
Co-mutagenic beta-carbolines, such as norharman and harman, were quantified in mainstream and sidestream smoke condensates of six Japanese brands of cigarettes, and also in 13 kinds of cooked foods, using a combination of blue cotton treatment and HPLC. Norharman and harman were detected in all the cigarette smoke condensate samples. Their levels in the mainstream smoke case were 900-4240 ng per cigarette for norharman, and 360-2240 ng for harman, and in sidestream smoke, 4130-8990 ng for norharman and 2100-3000 ng for harman. These beta-carbolines were also found to be present in all the cooked food samples, at levels of 2.39-795 ng for norharman and 0.62-377 ng for harman per gram of cooked food. The observed concentrations are much higher than those found for mutagenic and carcinogenic heterocyclic amines (HCAs), suggesting that humans are exposed to norharman and harman in daily life to a larger extent than to HCAs.
Background Obesity, an inflammatory condition linked to cardiovascular disease, is associated with expansion of adipose tissue. Highly prevalent coplanar polychlorinated biphenyls (PCBs) such as 3,3′,4,4′-tetrachlorobiphenyl (PCB-77) accumulate in adipose tissue because of their lipophilicity and increase with obesity. However, the effects of PCBs on adipocytes, obesity, and obesity-associated cardiovascular disease are unknown. Objectives In this study we examined in vitro and in vivo effects of PCB-77 on adipocyte differentiation, proinflammatory adipokines, adipocyte morphology, body weight, serum lipids, and atherosclerosis. Methods PCB-77 or 2,2′,4,4,5,5′-hexachlorobiphenyl (PCB-153) was incubated with 3T3-L1 adipocytes either during differentiation or in mature adipocytes. Concentration-dependent effects of PCB-77 were contrasted with those of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). For in vivo studies, we treated C57BL/6 wild-type (WT) or aryl hydrocarbon receptor (AhR)−/− mice with vehicle or PCB-77 (49 mg/kg, by intraperitoneal injection) and examined body weight gain. In separate studies, we injected ApoE−/− mice with vehicle or PCB-77 over a 6-week period and examined body weight, adipocyte size, serum lipids, and atherosclerosis. Results Low concentrations of PCB-77 or TCDD increased adipocyte differentiation, glycerol–3-phosphate dehydrogenase activity, and expression of peroxisome proliferator–activated receptor γ, whereas higher concentrations inhibited adipocyte differentiation. Effects of PCB-77 were abolished by the AhR antagonist α-naphthoflavone. PCB-77 promoted the expression and release of various proinflammatory cytokines from 3T3-L1 adipocytes. Administration of PCB-77 increased body weight gain in WT but not AhR−/− mice. ApoE−/− mice injected with PCB-77 exhibited greater body weight, adipocyte hypertrophy, serum dyslipidemia, and augmented atherosclerosis. Conclusions Our findings suggest that PCB-77 may contribute to the development of obesity and obesity-associated atherosclerosis.
BACKGROUND: A growing body of evidence shows that secondhand cigarette smoke undergoes numerous chemical changes after it is released into the air: it can adsorb to indoor surfaces, desorb back into the air and undergo chemical changes as it ages. OBJECTIVES: To test the effects of aging on the concentration of polycyclic aromatic hydrocarbons (PAHs), nicotine and tobacco-specific nitrosamines in cigarette smoke. METHODS: We generated sidestream and mainstream cigarette smoke with a smoking machine, diluted it with conditioned filtered air, and passed it through a 6 m(3) flow reactor with air exchange rates that matched normal residential air exchange rates. We tested the effects of 60 min aging on the concentration of 16 PAHs, nicotine, cotinine and tobacco-specific nitrosamines. We also measured sorption and deposition of nicotine, cotinine and tobacco-specific nitrosamines on materials placed within the flow reactor. RESULTS: We observed mass losses of 62% for PAHs, 72%, for nicotine, 79% for N-nitrosonornicotine and 80% for 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). Extraction of cotton cloth exposed to smoke yielded nicotine and NNK. The ratio of NNK:nicotine on the exposed cloth was 10-fold higher than that in aerosol samples. CONCLUSIONS: Our data suggest that the majority of the PAHs, nicotine, cotinine and tobacco-specific nitrosamines that are released during smoking in homes and public places deposit on room surfaces. These data give an estimate of the potential for accumulation of carcinogens in thirdhand cigarette smoke. Exposure to PAHs and tobacco-specific nitrosamines, through dermal absorption and inhalation of contaminated dust, may contribute to smoking-attributable morbidity and mortality.
BACKGROUND: Children from low-income families may be subject to high exposures to polycyclic aromatic hydrocarbons (PAH) which can lead to respiratory disorders. This study aims to establish methods for assessing total PAH exposure of asthmatic and non-asthmatic children from low-income families; to estimate serum PAH concentrations of these children, and to estimate the relative importance of the environmental pathways for PAH exposure. MATERIALS AND METHODS: A total of 75 (61 asthmatic, 14 non-asthmatic) Saudi children 15 years old and below were included to participate in this cross-sectional study. Each participant answered a generalized questionnaire with dietary questions. Serum PAH were measured using HPLC with UV detection. RESULTS: Serum naphthalene and pyrene were significantly elevated among asthmatic children (p-values = 0.007 and 0.01, respectively). Serum acenaphthylene, fluorine and 1,2-benzanthracene, on the other hand, were significantly higher among non-asthmatics (p-values = 0.001, 0.04 and 0.03, respectively). There was a significant correlation between the presence of a smoker in the family and serum concentrations of carbazole, pyrene, 1,2-benzanthracene and benzacephenanthrylene (R = 0.37, 0.45, 0.43, 0.33; p-values = 0.01, 0.0002, 0.003 and 0.025, respectively). Significant correlations were elicited between daily meat intake and serum levels of acenaphthylene, benzopyrene and 1,2-benzanthracene (R = 0.27, 0.27, 0.33; p-values = 0.02 and < 0.001, respectively). CONCLUSION: Among the children, serum PAH were significantly correlated to meat intake as well as presence of smokers at home. Public health awareness should be enhanced by educating parents to take certain precautions at home, such as preventing indoor smoking and reducing the intake of grilled and smoked meat by children so as to decrease their exposure to carcinogenic PAH.
Objectives The objective of this article is to extend our previous studies of persistent organic pollutant (POP) contamination of U.S. food by measuring perfluorinated compounds (PFCs), organochlorine pesticides, and polychlorinated biphenyls (PCBs) in composite food samples. This study is part of a larger study reported in two articles, the other of which reports levels of polybrominated diphenyl ethers and hexabromocyclododecane brominated flame retardants in these composite foods [Schecter et al. 2010. Polybrominated diphenyl ethers (PBDEs) and hexabromocyclodecane (HBCD) in composite U.S. food samples, Environ Health Perspect 118:357–362]. Methods In this study we measured concentrations of 32 organochlorine pesticides, 7 PCBs, and 11 PFCs in composite samples of 31 different types of food (310 individual food samples) purchased from supermarkets in Dallas, Texas (USA), in 2009. Dietary intake of these chemicals was calculated for an average American. Results Contamination varied greatly among chemical and food types. The highest level of pesticide contamination was from the dichlorodiphenyltrichloroethane (DDT) metabolite p,p′- dichlorodiphenyldichloroethylene, which ranged from 0.028 ng/g wet weight (ww) in whole milk yogurt to 2.3 ng/g ww in catfish fillets. We found PCB congeners (28, 52, 101, 118, 138, 153, and 180) primarily in fish, with highest levels in salmon (PCB-153, 1.2 ng/g ww; PCB-138, 0.93 ng/g ww). For PFCs, we detected perfluorooctanoic acid (PFOA) in 17 of 31 samples, ranging from 0.07 ng/g in potatoes to 1.80 ng/g in olive oil. In terms of dietary intake, DDT and DDT metabolites, endosulfans, aldrin, PCBs, and PFOA were consumed at the highest levels. Conclusion Despite product bans, we found POPs in U.S. food, and mixtures of these chemicals are consumed by the American public at varying levels. This suggests the need to expand testing of food for chemical contaminants.
Heterocyclic amines (HCAs) are formed when meat products such as beef, chicken, pork and fish are cooked at high temperatures. The most abundant HCA found in the human diet is 2-amino-1-methyl-6-phenylimidazo[4,5-b] pyridine (PhIP). PhIP causes mammary carcinomas in female rats and mice, and is associated with an increased risk of developing colon, breast, and prostate cancer in humans. PhIP is metabolized by cytochrome P-450s producing N-OH-PhIP. The N-OH-PhIP can be esterified by phase II enzymes forming an arylnitrenium ion that binds to DNA causing adducts. Furthermore, N-OH-PhIP may be reduced by cytochrome b5 reductase producing superoxide anions and hydroxyl radicals causing DNA strand breaks. Diallyl sulfide (DAS) has been shown to prevent cancer in several animal models, presumably by metabolic modulation. We hypothesize that PhIP produces reactive oxygen species causing DNA strand breaks and that DAS will inhibit the formation of PhIP induced DNA strand breaks. To test this hypothesis we treated normal breast epithelial (MCF-10A) cells with PhIP, DAS and a combination of PhIP and DAS. The detection of lipid peroxides was used as a surrogate for ROS. Lipid peroxides were detected using a PeroxiDetect kit (Sigma). PhIP increased the production of lipid peroxides and DAS decreased the PhIP-induced peroxidation by 47%. To determine if PhIP causes DNA strand breaks in MCF-10A cells, cells were treated for 3, 6, 9, and 24 h with PhIP (100 microM), DAS (100 microM) and a combination of PhIP (100 microM) and DAS (100 microM). DNA strand breaks were evaluated using the Comet assay. PhIP produced DNA strand breaks in a dose- and time-dependent fashion. We have shown that DAS inhibits PhIP-induced DNA strand breaks by inhibiting the production of reactive oxygen species. Therefore, we propose that DAS can prevent PhIP-induced breast cancer.
BACKGROUND: Drinking mate has been associated with cancers of the esophagus, oropharynx, larynx, lung, kidney, and bladder. We conducted this study to determine whether drinking mate could lead to substantial exposure to polycyclic aromatic hydrocarbons (PAH), including known carcinogens, such as benzo[a]pyrene. METHODS: The concentrations of 21 individual PAHs were measured in dry leaves of eight commercial brands of yerba mate and in infusions made with hot (80 degrees C) or cold (5 degrees C) water. Measurements were done using gas chromatography/mass spectrometry, with deuterated PAHs as the surrogates. Infusions were made by adding water to the leaves, removing the resulting infusion after 5 min, and then adding more water to the remaining leaves. This process was repeated 12 times for each infusion temperature. RESULTS: The total concentrations of the 21 PAHs in different brands of yerba mate ranged from 536 to 2,906 ng/g dry leaves. Benzo[a]pyrene concentrations ranged from 8.03 to 53.3 ng/g dry leaves. For the mate infusions prepared using hot water and brand 1, 37% (1,092 of 2,906 ng) of the total measured PAHs and 50% (25.1 of 50 ng) of the benzo[a]pyrene content were released into the 12 infusions. Similar results were obtained for other hot and cold infusions. CONCLUSION: Very high concentrations of carcinogenic PAHs were found in yerba mate leaves and in hot and cold mate infusions. Our results support the hypothesis that the carcinogenicity of mate may be related to its PAH content.
Fish and seal oil dietary supplements, marketed to be rich in omega-3 fatty acids, are frequently consumed by Canadians. Samples of these supplements (n = 30) were collected in Vancouver, Canada, between 2005 and 2007. All oil supplements were analyzed for polychlorinated biphenyls (PCBs) and organochlorine insecticides (OCs) and each sample was found to contain detectable residues. The highest SigmaPCB and SigmaDDT (1,1,1-trichloro-di-(4-chlorophenyl)ethane) concentrations (10400 ng/g and 3310 ng/g, respectively) were found in a shark oil sample while lowest levels were found in supplements prepared using mixed fish oils (anchovy, mackerel, and sardine) (0.711 ng SigmaPCB/g and 0.189 ng SigmaDDT/g). Mean SigmaPCB concentrations in oil supplements were 34.5, 24.2, 25.1, 95.3, 12.0, 5260, 321, and 519 ng/g in unidentified fish, mixed fish containing no salmon, mixed fish with salmon, salmon, vegetable with mixed fish, shark, menhaden (n = 1), and seal (n = 1), respectively. Maximum concentrations of the other OCs were generally observed in the seal oil. The hexachlorinated PCB congeners were the dominant contributors to SigmaPCB levels, while SigmaDDT was the greatest contributor to organochlorine levels. Intake estimates were made using maximum dosages on manufacturers' labels and results varied widely due to the large difference in residue concentrations obtained. Average SigmaPCB and SigmaDDT intakes were calculated to be 736 +/- 2840 ng/d and 304 +/- 948 ng/d, respectively.
U.S. and European regulators and researchers disagree over risks of a common class of surfactants.
The regular occurrence of a peak due to an unidentified substance (X) in the gas chromatographic traces obtained from phenolic extracts of urine from human pregnant and non-pregnant females has been reported. The biphasic excretion of X with maxima in the luteal phase of the ovulatory cycle and relatively high levels in the first trimester of pregnancy were noteworthy and suggested that the substance may have a biological significance. Close similarities between the excretory pattern, the chemical and chromatographic properties of X and of those of the known phenolic steroids suggested initially that this compound was steroidal in nature. The same, or a similar, substance seems to be excreted in the vervet monkey (Cercopithecus aethiops pygerythrus). We now report the excretory pattern of X in more detail, the isolation of the pure compound from pooled pregnancy urine and the chemical structure. The structure determined by mass spectrometry, IR spectroscopy and NMR spectrometry is: trans-(+/-)-3,4-bis[(3-hydroxyphenyl)methyl]dihydro-2-(3H)-furanone (HPMF) and was confirmed by synthesis.
The cooking-induced changes in the levels of polybrominated diphenyl ethers (PBDEs), hexachlorobenzene (HCB), and 16 polycyclic aromatic hydrocarbons (PAHs) in various foodstuffs were investigated. Foods included fish (sardine, hake and tuna), meat (veal steak, loin of pork, breast and thigh of chicken, and steak and rib of lamb), string bean, potato, rice, and olive oil. For each food item, raw and cooked (fried, grilled, roasted, boiled) samples were analyzed. There were some variations in the concentrations of PBDEs before and after cooking. However, they depended not only on the cooking process, but mainly on the specific food item. The highest HCB concentrations were found in sardine, being lower in cooked samples. All cooking processes enhanced HCB levels in hake, while very scarce differences could be noted in tuna (raw and cooked). In general terms, the highest PAH concentrations were found after frying by being the values especially notable in fish, excepting hake, where the highest total PAH levels corresponded to roasted samples. The results of this study show that, in general, cooking processes are only of a limited value as a means of reducing PBDE, HCB and PAH concentrations in food.
The association of 11 polychlorinated biphenyls (PCBs) with hypertension was investigated using the National Health and Nutrition Examination Survey (NHANES), 1999-2002. The unweighted number of participants assessed for hypertension ranged from 2074 to 2556 depending on the chemical(s) being analyzed. In unadjusted logistic regressions all 11 PCBs were associated with hypertension. After adjustment for age, gender, race, smoking status, body mass index, exercise, total cholesterol, and family history of coronary heart disease, seven of the 11 PCBs (PCBs 126, 74, 118, 99, 138/158, 170, and 187) were significantly associated with hypertension. The strongest adjusted associations with hypertension were found for dioxin-like PCBs 126 and 118. PCB 126>59.1 pg/g lipid adjusted had an odds ratio of 2.45 (95% CI 1.48-4.04) compared to PCB 126<or=26.1 pg/g lipid adjusted. PCB 118>27.5 ng/g lipid adjusted had an odds ratio of 2.30 (95% CI 1.29-4.08) compared to PCB 118<or=12.5 ng/g lipid adjusted. Moreover, participants with one or more elevated PCBs had an odds ratio of 1.84 (95% CI 1.25-2.70) compared to no PCBs elevated in an adjusted logistic regression. The prevalence of one or more elevated PCBs was 22.76% or 32 million of 142 million persons >or=20 years old in the non-institutionalized US population. We hypothesize that association of seven PCBs with hypertension indicates elevated PCBs are a risk factor for hypertension. What clinicians can do, given the results of this study, is limited unless the appropriate laboratory methods can be made more widely available for testing patients.
BACKGROUND: Xenobiotic organochlorine pesticides (OCPs) are a major environmental problem because of their historic widespread use, pronounced persistence against chemical and biological degradation, and bioaccumulation in the food chain. Pesticide use is prevalent in the production of edible bamboo shoots, which are exported widely from China. To evaluate the quality of Chinese bamboo shoots we determined the residual content of some OCPs in shoot samples. RESULTS: Three types of OCPs-hexachlorocyclohexane (HCH), 1,1,1-trichlor-2,2-bis(p-chlorophenyl)ethane (DDT) and pentachloronitrobenzene (PCNB)-were detected in bamboo shoots from Zhejiang province, China. Detection rates were 100%, 100% and 75% for HCH, DDT and PCNB, respectively. However, the average residue concentration did not exceed the maximum residue limit for pesticides detected in food in China (50 µg kg(-1) ). In terms of residue concentrations of the pesticides, 82.14% of the bamboo shoot samples could be classified as safe. CONCLUSION: While all sampled bamboo shoots contained OCP, most (82.14%) were safe for consumption. 2010 Society of Chemical Industry.
Low molecular weight phenols of plant origin are undoubtedly semiochemicals although not all of them can be easily classified as typical allelochemicals, which straightforwardly benefit the releaser. We have selected and surveyed this particular class of secondary metabolites, which shares high chemical reactivity with intrinsic biocompatibility and affinity for variety of molecular targets gained through evolution, because their suitability as prospective lead compounds for medicinal chemistry seems high but relatively unexplored. In particular, plant phenolics could be perceived as a natural product library, which contains privileged scaffolds, as evidenced by examples of endogenous phenols, phytochemicals containing aryl hydroxyl groups and phenolic synthetic drugs. It is postulated that application of bio-chemo-informatic tools to such library can be helpful in pulling out new drug candidates as well as in validating ADMET compatibility and suitability of the old ones. After short survey of structural diversity represented by plant phenolics, we focus on the compounds which either have obvious dietary significance or rich record of pharmacological studies, or both. It can be seen that apart from growing use of phytochemicals in dietary supplements, slow progress through clinical trials towards new drug registration is observed in that category of natural products. Such waste of resources on the way of transformation from renewable materials to high tech/high value products aimed for improved human healthcare is deplorable and should be reformed in name of sustainability. We attempt to answer the question why popular plant phenolics with well established health benefits and reasonably well recognized molecular pharmacology (such as: catechins, curcumin, resveratrol, quercetin and its glycosides, genistein, silymarin) have difficulties in attaining registered drug or even IND level.
Mean hexachlorobenzene (HCB) and hexachlorocyclohexane (HCH) concentrations, measured in seawater and air samples, confirmed the decline in levels of these compounds in Antarctic air and water. However, low alpha/gamma-HCH ratios in air at the beginning of the sampling period suggest a predominance of fresh lindane entering the Antarctic atmosphere during the Austral spring probably due to current use in the Southern Hemisphere. Water-air fugacity ratios demonstrate the potential for HCH gas deposition to coastal Antarctic seas, while the water-air fugacity ratios for HCB imply that volatilization does not account for the observed decrease of HCB in surface seawater. HCH concentrations found in krill samples were correlated with seawater concentrations indicative of bioconcentration of HCHs from seawater.
2- and 4-methylimidazoles are present as contaminants in caramel colorings manufactured with ammonia catalysts. Both contaminants have been shown to induce cancer in animals and may be present in caramel colorings in amounts that exceed federal guidelines. California requires warning notices on products that could lead to consumption of more than 30 micrograms per day. The US Food and Drug Administration should bar the use of excessively contaminated caramel coloring in food.
Heteroyclic aromatic amines (HAAs) are a class of hazardous chemicals that are receiving heightened attention as a risk factor for human cancer. HAAs arise during the cooking of meats, fish, and poultry, and several HAAs also occur in tobacco smoke condensate and diesel exhaust. Many HAAs are carcinogenic and induce tumors at multiple sites in rodents. A number of epidemiologic studies have reported that frequent consumption of well-done cooked meats containing HAAs can result in elevated risks for colon, prostate, and mammary cancers. Moreover, DNA adducts of HAAs have been detected in human tissues, demonstrating that HAAs induce genetic damage even though the concentrations of these compounds in cooked meats are generally in the low parts-per-billion (ppb) range. With recent improvements in sensitivity of mass spectrometry instrumentation, HAAs, their metabolites, and DNA adducts can be detected at trace amounts in biological fluids and tissues of humans. The incorporation of HAA biomarkers in epidemologic studies will help to clarify the role of these dietary genotoxicants in the etiology of human cancer.