Investigations into the potential degradation of polycarbonate baby bottles during sterilization with consequent release of bisphenol A

Mechanical Washing Prevents Transmission of Bacterial, Viral, and Protozoal Murine Pathogens from Cages

Infectious agents have varying susceptibilities to thermal inactivation and/or mechanical removal from cages by the use of heated, pressurized water. In this study, we tested whether 5 specific infectious organisms (Candidatus savagella [segmented filamentous bacterium (SFB)], Helicobacter sp., mouse norovirus (MNV), Tritrichomonas sp., and Entamoeba muris) could survive the cage wash process and still infect naïve mice. These 5 organisms were chosen due to their prevalence in rodent colonies, environmental stability, and/or potential to influence experimental outcomes. Cages that had housed mice shedding all 5 organisms were assigned to 1 of 3 treatment groups: 1) sanitization in a tunnel washer followed by autoclaving (121 °C [250 °F] for 20 min; n = 40 cages); 2) sanitization in a tunnel washer (82 °C [180 °F] for an average of 30 s; n = 40 cages); or 3) control (bedding change only; n = 40 cages). The presence of these agents in the cage was assessed by performing PCR on swabs of the empty soiled cage interior before and after the treatment. In addition, to determine if any residual nucleic acid was infectious, 2 Swiss outbred (J:ARC(S)) female mice were housed for 7 d in cages from each treatment group. The above procedures were then repeated so that every week each pair of J:ARC(S) mice ( n = 10 pairs of mice/treatment group) were housed in another cage that underwent the same treatment; this was done for a total of 4 consecutive, 1-wk-long periods. Swabs collected from soiled cages were PCR-positive for SFB, Helicobacter, MNV, Tritrichomonas, and Entamoeba in 99%, 97%, 39%, 63%, and 73% of the cages tested, respectively. Cages in the tunnel wash group that were PCR-positive for SFB, Helicobacter, Tritrichomonas, and Entamoeba before treatment remained PCR-positive in 8%, 15%, 43%, and 10% of positive cages, respectively. None of the cages from the autoclave group were PCR-positive for any of the agents after treatment. None of the mice housed in cages in either the autoclave or tunnel wash groups became infected with any of the agents. However, 80%, 60%, and 100% of the pairs of mice housed in untreated cages were PCR-positive for SFB, MNV, and Entamoeba, respectively. None of the mice housed in untreated cages were positive for Helicobacter or Tritrichomonas. Our results suggest that nucleic acids from these bacterial and protozoal organisms may remain in cages after mechanical cage washing, but these nucleic acids are not infectious, and autoclaving is not necessary to prevent transmission.

Simultaneous determination of phthalates and bisphenols from plastic bottled water samples by dispersive solid-phase extraction with multiwalled carbon nanotubes and liquid chromatography/atmospheric pressure photoionization/high-resolution mass spectrometry

RATIONALE

Phthalates and bisphenols were reported as endocrine disrupting chemicals and hence a potential threat to human health. Polyethylene terephthalate bottles are being used to store drinking water and the probability of migration of phthalates and bisphenols from the bottles into the water is high. The migration of analytes with respect to different storage conditions need to be studied.

METHOD

A sensitive analytical method for simultaneous determination of seven phthalates and three bisphenols from packaged drinking water was developed using liquid chromatography/atmospheric pressure photoionization/high-resolution mass spectrometry. The analytes were extracted by dispersive solid-phase extraction by multiwalled carbon nanotubes.

RESULTS

The developed method showed linearity from 0.5 to 5000 μg/L with the limit of detection and limit of quantification ranging from 0.5 to 1 μg/L and 1 to 2 μg/L, respectively, for phthalates and bisphenols. The inter- and intraday variations were below 10%. The recoveries were in the range of 79.5% to 112%. The migration of phthalates and bisphenols increased with storage time and temperature. Maximum migration was observed for diisobutyl phthalate of 1209.7 ng/L followed by dibutyl phthalate at 777.8 ng/L on 180 days of analysis at room temperature. Migration of bis(2-ethylhexyl) phthalate was observed to be higher at elevated temperatures, increasing from 14.9 to 514 ng/L. Similarly, migration of bisphenol-A was increased at 45°C. The results were subjected to analysis of variance (ANOVA) studies and the results showed significant variations of phthalates and bisphenols with respect to storage temperature and time.

CONCLUSION

The use of atmospheric pressure photoionization facilitated simultaneous determination of phthalates and bisphenols. The migration of phthalates and bisphenols increased with increasing temperature and storage time. Maximum migration was observed for diethyl, diisobutyl, dibutyl and bis(2-ethylhexyl) phthalates. This may be attributed to the type of plastic, the processing parameters and recycling.

In utero exposure to endocrine-disrupting chemicals, maternal factors and alterations in the epigenetic landscape underlying later-life health effects

Widespread persistence of endocrine-disrupting chemicals (EDCs) in the environment has mandated the need to study their potential effects on an individual's long-term health after both acute and chronic exposure periods. In this review article a particular focus is given on in utero exposure to EDCs in rodent models which resulted in altered epigenetic programming and transgenerational effects in the offspring causing disrupted reproductive and metabolic phenotypes. The literature to date establishes the impact of transgenerational effects of EDCs potentially associated with epigenetic mediated mechanisms. Therefore, this review aims to provide a comprehensive overview of epigenetic programming and it's regulation in mammals, primarily focusing on the epigenetic plasticity and susceptibility to exogenous hormone active chemicals during the early developmental period. Further, we have also in depth discussed the epigenetic alterations associated with the exposure to selected EDCs such as Bisphenol A (BPA), di-2-ethylhexyl phthalate (DEHP) and vinclozlin upon in utero exposure especially in rodent models.

The role of mass spectrometry and related techniques in the analysis of extractable and leachable chemicals

In addition to degradation products, impurities, and exogenous contaminants, industries such as pharmaceutical, food, and others must concern themselves with leachables. These chemicals can derive from containers and closures or migrate from labels or secondary containers and packaging to make their way into products. Identification and quantification of extractables (potential leachables) and leachables, typically trace level analytes, is a regulatory expectation intended to ensure consumer safety and product fidelity. Mass spectrometry and related techniques have played a significant role in the analysis of extractables and leachables (E&L). This review provides an overview of how mass spectrometry is used for E&L studies, primarily in the context of the pharmaceutical industry. This review includes work flows, examples of how identification and quantification is done, and the importance of orthogonal data from several different detectors. E&L analyses are driven by the need for consumer safety. These studies are expected to expand in existing areas (e.g., food, textiles, toys, etc.) and into new, currently unregulated product areas. Thus, this topic is of interest to audiences beyond just the pharmaceutical and health care industries. Finally, the potential of universal detector approaches used in other areas is suggested as an opportunity to drive E&L research progress in this arguably understudied, under-published realm.

Alteration in apoptotic rate of testicular cells and sperms following administration of Bisphenol A (BPA) in Wistar albino rats

The aim of the study was to evaluate the effect of Bisphenol A [BPA] widely used as a plasticizer in the formation of polycarbonate plastics and epoxy resins, exposure causing alteration in apoptosis rate, and protective effect of Vitamin E when supplemented with BPA orally. Adult male Wistar albino rats aged 3 months were randomly divided into seven groups: control (olive oil treated) BPA-treated (dose 5, 50,100 μg/100gmBW) and Vitamin E intervention group (dose 5, 50, 100 μg/100gmBW BPA+ Vitamin E dose 4 mg/100gmBW). Animals were sacrificed 3 months later, and blood and tissue samples were collected. Apoptotic changes were analyzed in epididymal spermatozoa and testis tissue by binding of annexin V apoptotic biomarker. A significant decline in the weight of testis, testosterone level, and sperm count was observed. Histopathological and apoptotic changes were observed in testis tissue. In epididymal sperms, the early apoptotic cells were observed by staining of annexin V-conjugated FITC and PI green fluorescence in spermatozoa head which indicated the damage of membrane and late apoptotic cells. These changes reduced significantly in Vitamin E-treated groups though were not found to be comparable to control animals. All these changes were attributed to disrupted spermatogenesis that would interfere with sperm formation. Thus, the study infers that BPA affects the apoptosis process in the testis and epididymal sperm that would interfere with its function and contribute to infertility, whereas Vitamin E-supplemented dose has a protective effect towards these changes, indicating its role in improving male fertility.

Influence of Food with High Moisture Content on Oxygen Barrier Property of Polyvinyl Alcohol (PVA)/Vermiculite Nanocomposite Coated Multilayer Packaging Film

This study investigates the potential complications in applying nanoclay-based waterborne coating to packaging films for food with high moisture content. Multilayer packaging films were prepared by dry laminating commercially available polyvinyl alcohol (PVA)/vermiculite nanocomposite coating films and linear low-density polyethylene film, and the changes in oxygen barrier properties were investigated according to different relative humidity using 3 types of food simulants. When the relative humidity was above 60%, the oxygen permeability increased sharply, but this was reversible. Deionized water and 3% acetic acid did not cause any large structural change in the PVA/vermiculite nanocomposite but caused a reversible deterioration of the oxygen barrier properties. In contrast, 50% ethanol, a simulant for the semifatty food, induced irreversible structural changes with deterioration of the oxygen barrier property. These changes are due to the characteristics of PVA rather than vermiculite.

PRACTICAL APPLICATION

We believe this manuscript would be of interest to the wide group of researchers, organizations, and companies in the field of developing nanoclay-based gas barrier packaging for foods with high moisture content. Hence, we wish to diffuse our knowledge to the scientific community.

Determination of bisphenols with estrogenic activity in plastic packaged baby food samples using solid-liquid extraction and clean-up with dispersive sorbents followed by gas chromatography tandem mass spectrometry analysis

Bisphenols (BPs) are a family of chemicals with known endocrine disrupting activity. Bisphenol A (BPA) is the most representative prototype of this group of chemicals. Recently, the use of BPA, a prototype of endocrine disruptors, has been reduced and replaced with structural analogs due to its negative effects on both the environment and consumers. In this work, a new method is presented for the determination of seven BPs, with estrogenic activity in ready-to-eat plastic packaged baby foods. The procedure involves the isolation of the analytes using solid-liquid phase extraction with acetonitrile followed by a clean-up step with a mixture of dispersive-SPE sorbents (C18 and PSA) and magnesium sulphate, to reduce matrix effect from proteins, sugars and lipids. Extraction parameters were optimized using multivariate optimization methods. The compounds were detected and quantified by gas chromatography tandem mass spectrometry (GC-MS/MS). The limits of quantification were between 0.1 and 1.2ngg^-1 for the studied analytes. The method was validated using matrix-matched calibration and recovery assays with spiked samples. Recovery rates were between 91% and 110% and % RSD was lower than 13% in all cases. The method has been successfully applied for the determination of these endocrine disrupting chemicals (EDCs) in samples of a novel type of food consumed by pre-schoolers. This is the first study to analyze EDCs in plastic packaged foods consumed by this target group.

The role of polycarbonate monomer bisphenol-A in insulin resistance

Bisphenol A (BPA) is a synthetic unit of polycarbonate polymers and epoxy resins, the types of plastics that could be found in essentially every human population and incorporated into almost every aspect of the modern human society. BPA polymers appear in a wide range of products, from liquid storages (plastic bottles, can and glass linings, water pipes and tanks) and food storages (plastics wraps and containers), to medical and dental devices. BPA polymers could be hydrolyzed spontaneously or in a photo- or temperature-catalyzed process, providing widespread environmental distribution and chronic exposure to the BPA monomer in contemporary human populations. Bisphenol A is also a xenoestrogen, an endocrine-disrupting chemical (EDC) that interferes with the endocrine system mimicking the effects of an estrogen and could potentially keep our endocrine system in a constant perturbation that parallels endocrine disruption arising during pregnancy, such as insulin resistance (IR). Gestational insulin resistance represents a natural biological phenomenon of higher insulin resistance in peripheral tissues of the pregnant females, when nutrients are increasingly being directed to the embryo instead of being stored in peripheral tissues. Gestational diabetes mellitus may appear in healthy non-diabetic females, due to gestational insulin resistance that leads to increased blood sugar levels and hyperinsulinemia (increased insulin production from the pancreatic beta cells). The hypothesis states that unnoticed and constant exposure to this environmental chemical might potentially lead to the formation of chronic low-level endocrine disruptive state that resembles gestational insulin resistance, which might contribute to the development of diabetes. The increasing body of evidence supports the major premises of this hypothesis, as exemplified by the numerous publications examining the association of BPA and insulin resistance, both epidemiological and mechanistic. However, to what extent BPA might contribute to the development of diabetes in the modern societies still remains unknown. In this review, I discuss the chemical properties of BPA and the sources of BPA contamination found in the environment and in human tissues. I provide an overview of mechanisms for the proposed role of bisphenol A in insulin resistance and diabetes, as well as other related diseases, such as cardiovascular diseases. I describe the transmission of BPA effects to the offspring and postulate that gender related differences might originate from differences in liver enzyme levels, such as UDP-glucuronosyltransferase, which is involved in BPA processing and its elimination from the organism. I discuss the molecular mechanisms of BPA action through nuclear and membrane-bound ER receptors, non-monotonic dose response, epigenetic modifications of the DNA and propose that chronic exposure to weak binders, such as BPA, may mimic the effects of strong binders, such as estrogens.

Identification and quantification of bisphenol A and bisphenol B in polyvinylchloride and polycarbonate medical devices by gas chromatography with mass spectrometry

A gas chromatography with mass spectrometry method has already been developed and published for the identification and quantification of 14 phthalates and five nonphthalate plasticizers in polyvinylchloride medical devices. In order to assay, in addition to plasticizers, bisphenols A and B possibly present in polyvinylchloride samples, this previous method was extended to the assay of these additional potential endocrine disruptors. Furthermore, as bisphenol A could also be present in polycarbonate samples, the method used for the polyvinylchloride sample was tested and validated for the assay of bisphenols A and B in polycarbonate medical devices. The separation of all compounds, including bisphenols A and B, is obtained on a cross-linked 5%-phenyl/95%-dimethylpolysiloxane capillary column using a temperature gradient. For both plastics, samples are dissolved in tetrahydrofuran followed by a precipitation of the plastic by addition of ethanol. Results obtained point out residual bisphenol A amounts for polycarbonate samples ranging from 0.6 to 0.8% and for polyvinylchloride samples less or equal to 5 ppm. No bisphenol B was detected in the samples tested. For bisphenols A and B, mean recoveries obtained on spiked polyvinylchloride or polycarbonate sample preparations ranged from 87 to 108% in accordance with in-house specification (80-110%).

Human Bisphenol A Exposure and the "Diabesity Phenotype"

Bisphenol A (BPA), a known endocrine disruptor, is a food contaminant suspected of being a contributing factor to the present-day increase in obesity, diabetes, and cardiovascular disease. This issue is of increasing interest in the field of diabetes research and has become a matter of concern for regulatory agencies and food industries. Recently, the number of studies involving BPA has increased exponentially, but there are still many gaps in the knowledge of the relationship between actual BPA exposure and cardiometabolic risk and of the modalities of food intake exposure, all of which prevents sound judgments concerning the risks to human health. This review focuses on the association between human exposure to BPA and obesity, thyroid function, diabetes, insulin resistance, metabolic syndrome, cardiovascular diseases, and BPA content in food. Many cross-sectional studies support, sometimes contradictorily, an adverse effect of BPA exposure on obesity, diabetes, and cardiovascular diseases. Few prospective studies support an adverse effect of BPA exposure on such pathologies. Moreover, no intervention studies have been conducted to evaluate the causality of such associations. This is mainly due to lack of an appropriate database of BPA content in foods, thus hindering any estimation of the usual dietary BPA intake.

Environmental induction of the fetal epigenome

The healthy adult is the result of successful interaction between the maternal environment and the developing fetal epigenome. The Barker hypothesis first suggested that in utero exposure to the maternal environment impacts adult health and disease. Since the origin of this theory, numerous studies have lent further support. Epigenomic alteration involves DNA methylation and histone modifications. Pregnancy, when the epigenome is typically actively programmed, is a vulnerable time, when exposures may have the most profound epigenetic effect. Recent advances have allowed an understanding of the extent and mechanism by which environmental exposures alter the epigenome of the fetus. Healthcare providers who treat and counsel reproductive-age women are in a unique position to protect against these epigenetic alterations and therefore prevent adverse impact on the developing fetus that may manifest throughout life.

Maternal exposure to bisphenol A may increase the risks of Parkinson's disease through down-regulation of fetal IGF-1 expression

So far, the pathogenesis of Parkinson's disease (PD) remains unclear. Current studies implicate environmental toxins may be potential causes of fetal origin of PD. BPA is a member of the family of estrogenic chemicals existing widely in environment. Significant evidences from animal experimentation have demonstrated that BPA interfere with fetal neurodevelopment. Based on previous reports and our research on EB derived from hESCs, we speculate that maternal exposure to low-dose BPA during gestational period may decrease IGF-1 expression, thus hinder the development of fetal DA neurons, and finally increase the risks of fetal origin of PD. Our hypothesis may shed new light on the pathogenesis of PD and lead to potential preventive treatments.

Bisphenol A exposure, effects, and policy: a wildlife perspective

Thousands of anthropogenic chemicals are present in the environment, and mounting evidence indicates that some have endocrine-disrupting effects in a variety of organisms. Of particular concern are chemicals that act as agonists or antagonists on vertebrate estrogen or androgen receptors. One such compound is bisphenol A (BPA), which appears to be both an estrogen receptor agonist and an androgen receptor antagonist. Used in the manufacture of plastic resins, BPA is found at low levels in surface-water, sediments, soils, and biota. Although it degrades quickly, it is pseudo-persistent in the environment because of continual inputs. Due to its environmental ubiquity, organisms may be exposed to BPA chronically or during sensitive life stages. While the impacts of BPA-related endocrine disruption in humans have been extensively studied, the endocrinal and systemic effects in wildlife are less well known. This article reviews the current state of knowledge of BPA inputs to the environment, routes of exposure, and effects on wildlife. We then critically examine the regulatory structure governing the environmental endpoints of BPA in the United States, European Union, and Canada, and discuss major challenges to the effective regulation of BPA. We conclude with a survey of treatment and mitigation options.

Urinary bisphenol A concentrations in girls from rural and urban Egypt: a pilot study

BACKGROUND

Exposure to endocrine active compounds, including bisphenol A (BPA), remains poorly characterized in developing countries despite the fact that behavioral practices related to westernization have the potential to influence exposure. BPA is a high production volume chemical that has been associated with metabolic dysfunction as well as behavioral and developmental effects in people, including children. In this pilot study, we evaluate BPA exposure and assess likely pathways of exposure among girls from urban and rural Egypt.

METHODS

We measured urinary concentrations of total (free plus conjugated) species of BPA in spot samples in urban (N = 30) and rural (N = 30) Egyptian girls, and compared these concentrations to preexisting data from age-matched American girls (N = 47) from the U.S. National Health and Nutrition Examination Survey (NHANES). We also collected anthropometric and questionnaire data regarding food storage behaviors to assess potential routes of exposure.

RESULTS

Urban and rural Egyptian girls exhibited similar concentrations of urinary total BPA, with median unadjusted values of 1.00 and 0.60 ng/mL, respectively. Concentrations of urinary BPA in this group of Egyptian girls (median unadjusted: 0.70 ng/mL) were significantly lower compared to age-matched American girls (median unadjusted: 2.60 ng/mL) according to NHANES 2009-2010 data. Reported storage of food in plastic containers was a significant predictor of increasing concentrations of urinary BPA.

CONCLUSIONS

Despite the relatively low urinary BPA concentrations within this Egyptian cohort, the significant association between food storage behaviors and increasing urinary BPA concentration highlights the need to understand food and consumer product patterns that may be closing the gap between urban and rural lifestyles.

Identification and quantification of the migration of chemicals from plastic baby bottles used as substitutes for polycarbonate

The results of a study on the analytical identification and quantification of migration of chemicals from plastics baby bottles found in the European Union market made of materials that are now present as substitutes for polycarbonate (PC) are reported. A total of 449 baby bottles with a focus on first age or sets of bottles were purchased from 26 European Union countries, Canada, Switzerland and the USA. From this collection, which contained several duplicates, a total of 277 baby bottles were analysed. The materials included different types of plastic such as PC, polyamide (PA), polyethersulphone (PES), polypropylene (PP), but also silicone, and from the United States a co-polyester marketed under the trade name Tritan™. The bottles were subjected to the conventional migration test for hot fill conditions, i.e. 2 h at 70°C. The simulant used was that specified in European Union legislation (2007/19/EC) for milk, i.e. 50% ethanol. In a first phase 1, migration was conducted since the scope of this investigation was a screening rather than a true compliance testing check. Second and third migrations were performed on selected articles when migrated substances exceeded limits specified in the legislation. In order to verify some materials, a portion of the bottle was cut to run an FT-IR fingerprint to confirm the nature of the polymer. The migration solutions in general showed a low release of substances. Results showed that bottles made of PP and silicones showed a greater number of substances in the migration solutions and in greater quantity. Chemicals from PP included alkanes, which could be found in >65% of the bottles at levels up to 3500 µg kg⁻¹; and benzene derivatives in 17% of the baby bottles and found at levels up to 113 µg kg⁻¹. Some substances were found on a regular basis such as plasticisers, esters and antioxidants (e.g. tris(2,4-di-tert-butylphenyl)phosphate, known as Irgafos 168. Some substances found were not included in the Community positive list, which means that those should not be found even in the first migration. Such substances included 2,6-di-isopropylnaphthalene (DIPN), found in 4% of the bottles at levels up to 25 µg kg⁻¹, 2,4-di-tert-butyl phenol (in 90% of the bottles at levels up 400 µg kg⁻¹). Moreover, bisphenol A (BPA) was detected and quantified in baby bottles made of PA, but limited to one brand and model specific (but labelled BPA free). Results for baby bottles made of silicone also indicated the presence of components, e.g. potentially coming from inks (benzophenone, diisopropyl naphtahalene - DIPN, which could come for example from the presence of instruction leaflets in the bottles). In the case of silicone, phthalates were also found in relevant concentrations, with levels for DiBP and DBP from the first migration test of 50-150 µg kg⁻¹ and DEHP at levels 25-50 µg kg⁻¹.

Bisphenol A increases mammary cancer risk in two distinct mouse models of breast cancer

Bisphenol A (BPA) is an industrial plasticizer that leaches from food containers during normal usage, leading to human exposure. Early and chronic exposure to endocrine-disrupting environmental contaminants such as BPA elevates the potential for long-term health consequences. We examined the impact of BPA exposure on fetal programming of mammary tumor susceptibility as well as its growth promoting effects on transformed breast cancer cells in vivo. Fetal mice were exposed to 0, 25, or 250 μg/kg BPA by oral gavage of pregnant dams. Offspring were subsequently treated with the known mammary carcinogen, 7,12-dimethylbenz[a]anthracene (DMBA). While no significant differences in postnatal mammary development were observed, both low- and high-dose BPA cohorts had a statistically significant increase in susceptibility to DMBA-induced tumors compared to vehicle-treated controls. To determine if BPA also promotes established tumor growth, MCF-7 human breast cancer cells were subcutaneously injected into flanks of ovariectomized NCR nu/nu female mice treated with BPA, 17beta-estradiol, or placebo alone or combined with tamoxifen. Both estradiol- and BPA-treated cohorts formed tumors by 7 wk post-transplantation, while no tumors were detected in the placebo cohort. Tamoxifen reversed the effects of estradiol and BPA. We conclude that BPA may increase mammary tumorigenesis through at least two mechanisms: molecular alteration of fetal glands without associated morphological changes and direct promotion of estrogen-dependent tumor cell growth. Both results indicate that exposure to BPA during various biological states increases the risk of developing mammary cancer in mice.

Bisphenol-A exposure alters endometrial progesterone receptor expression in the nonhuman primate

OBJECTIVE

To evaluate the effect of bisphenol-A (BPA), a xenoestrogen endocrine disruptor, on endometrial P receptor (PR) expression in nonhuman primates and human cells.

DESIGN

Controlled trial in primates.

SETTING

University.

ANIMAL(S)

African green monkeys.

INTERVENTION(S)

After oophorectomy, BPA (50 μg/kg/d), E(2), both, or vehicle control were administered. Estradiol and BPA were used in Ishikawa cells.

MAIN OUTCOME MEASURE(S)

Progesterone receptor expression using immunohistochemistry and quantitative polymerase chain reaction.

RESULT(S)

Progesterone receptor expression was increased in E(2)-treated primates compared with controls. Exposure to the combination of E(2) and BPA resulted in decreased PR expression compared with E(2) exposure alone. In Ishikawa cells treated with E(2), PR expression increased 5.1-fold; however, when Ishikawa cells were simultaneously treated with E(2) and BPA, PR expression was decreased to 0.6-fold that of cells treated with E(2) alone.

CONCLUSION(S)

Bisphenol-A alone functions as a weak estrogen. However, when administered with E(2), BPA diminishes E(2)-induced PR expression. The estrogen-like effect of BPA reported in exposed humans may be mediated by PR blockade and a resultant decrease in the estrogen inhibition normally imparted by P. Diminished PR expression may underlie previous reports linking BPA exposure to endometrial dysfunction in humans.

Epigenetic influences of low-dose bisphenol A in primary human breast epithelial cells

Substantial evidence indicates that exposure to bisphenol A (BPA) during early development may increase breast cancer risk later in life. The changes may persist into puberty and adulthood, suggesting an epigenetic process being imposed in differentiated breast epithelial cells. The molecular mechanisms by which early memory of BPA exposure is imprinted in breast progenitor cells and then passed onto their epithelial progeny are not well understood. The aim of this study was to examine epigenetic changes in breast epithelial cells treated with low-dose BPA. We also investigated the effect of BPA on the ERα signaling pathway and global gene expression profiles. Compared to control cells, nuclear internalization of ERα was observed in epithelial cells preexposed to BPA. We identified 170 genes with similar expression changes in response to BPA. Functional analysis confirms that gene suppression was mediated in part through an ERα-dependent pathway. As a result of exposure to BPA or other estrogen-like chemicals, the expression of lysosomal-associated membrane protein 3 (LAMP3) became epigenetically silenced in breast epithelial cells. Furthermore, increased DNA methylation in the LAMP3 CpG island was this repressive mark preferentially occurred in ERα-positive breast tumors. These results suggest that the in vitro system developed in our laboratory is a valuable tool for exposure studies of BPA and other xenoestrogens in human cells. Individual and geographical differences may contribute to altered patterns of gene expression and DNA methylation in susceptible loci. Combination of our exposure model with epigenetic analysis and other biochemical assays can give insight into the heritable effect of low-dose BPA in human cells.

Migration of 2-butoxyethyl acetate from polycarbonate infant feeding bottles

An enforcement campaign was carried out to assess the migration of 2-butoxyethyl acetate (2-BEA) from polycarbonate infant feeding bottles intended for repeated use. Migration was measured by three successive migration tests into two of the European Union official food simulants: distilled water and 3% acetic acid testing at 40 degrees C for 10 days. The Danish Veterinary and Food Administration (DVFA) has assessed that a migration above 0.33 mg for 2-BEA and a group of eight related substances kg(-1) foodstuff from plastics articles used exclusively for infants is unacceptable. Migration of 2-BEA was found from eight of 12 bottles. However, migration above the target value of 0.33 mg kg(-1) was not observed in the third decisive test from any of the 12 different brands of polycarbonate feeding bottles. A migration of between 0.05 and 0.26 mg kg(-1) from seven of 12 bottles was measured to 3% acetic acid in the third test, whereas no migration to distilled water was observed in the third test. The average recovery of 2-BEA after the 10-day exposure at the target value of 0.33 mg kg(-1) was 77% into distilled water and 36% into 3% acetic acid. The limited recovery was understandable as 2-BEA was partly hydrolysed in the aqueous food simulants and 2-butoxyethanol, a hydrolysis product and one of the related substances was identified. Quantification was carried out using gas chromatography after liquid/liquid extraction of the food simulant.

Migration of bisphenol A from plastic baby bottles, baby bottle liners and reusable polycarbonate drinking bottles

Human exposure to bisphenol A (BPA) has recently received special attention. It has been shown that exposure to BPA may occur through the consumption of beverages or foods that have been in contact with polycarbonate (PC) plastic containers or epoxy resins in food packaging. A BPA migration study was conducted using a variety of plastic containers, including polycarbonate baby bottles, non-PC baby bottles, baby bottle liners, and reusable PC drinking bottles. Water was used to simulate migration into aqueous and acidic foods; 10% ethanol solution to simulate migration to low- and high-alcoholic foods; and 50% ethanol solution to simulate migration to fatty foods. By combining solid-phase extraction, BPA derivatization and analysis by GC-EI/MS/MS, a very low detection limit at the ng l(-1) level was obtained. Migration of BPA at 40 degrees C ranged from 0.11 microg l(-1) in water incubated for 8 h to 2.39 microg l(-1) in 50% ethanol incubated for 240 h. Residual BPA leaching from PC bottles increased with temperature and incubation time. In comparison with the migration observed from PC bottles, non-PC baby bottles and baby bottle liners showed only trace levels of BPA. Tests for leachable lead and cadmium were also conducted on glass baby bottles since these represent a potential alternative to plastic bottles. No detectable lead or cadmium was found to leach from the glass. This study indicated that non-PC plastic baby bottles, baby bottle liners and glass baby bottles might be good alternatives for polycarbonate bottles.

Study on the migration of bisphenol-A from baby bottles by stir bar sorptive extraction-thermal desorption-capillary GC-MS

Migration of bisphenol-A (BPA), the principal monomer of polycarbonate (PC) baby bottles, was investigated using an aqueous migration simulant. BPA was determined in 200 mL water samples using stir bar sorptive extraction (SBSE) after in situ derivatization with acetic acid anhydride followed by thermal desorption (TD)-capillary GC-MS. The concentration of BPA was calculated using the deuterated internal standard d6-BPA. Calibration for BPA was shown to be linear in a concentration range from 1 ng/L to 10 microg/L with a correlation coefficient >0.99. The LOD for BPA (as acetate) was 0.12 ng/L and LOQ 0.40 ng/L (ppt). PC bottles were heated in a water bath and in a microwave oven at four different temperatures (37, 53, 65, and 85 degrees C). The higher the temperature, the more the BPA was released, and after a few heating cycles, the released concentrations became constant. At normal use, i.e. at 37 degrees C, concentrations are ca. 10 ng/L. No significant difference was noted between water bath and microwave heating illustrating that migration of BPA is mainly temperature dependent.

Bisphenol-A exposure in utero leads to epigenetic alterations in the developmental programming of uterine estrogen response

Bisphenol-A (BPA) is a nonsteroidal estrogen that is ubiquitous in the environment. The homeobox gene Hoxa10 controls uterine organogenesis, and its expression is affected by in utero BPA exposure. We hypothesized that an epigenetic mechanism underlies BPA-mediated alterations in Hoxa10 expression. We analyzed the expression pattern and methylation profile of Hoxa10 after in utero BPA exposure. Pregnant CD-1 mice were treated with BPA (5 mg/kg IP) or vehicle control on d 9-16 of pregnancy. Hoxa10 mRNA and protein expression were increased by 25% in the reproductive tract of mice exposed in utero. Bisulfite sequencing revealed that cytosine-guanine dinucleotide methylation was decreased from 67 to 14% in the promoter and from 71 to 3% in the intron of Hoxa10 after in utero BPA exposure. Decreased DNA methylation led to an increase in binding of ER-alpha to the Hoxa10 ERE both in vitro as and in vivo as determined by EMSA and chromatin immunoprecipitation, respectively. Diminished methylation of the ERE-containing promoter sequence resulted in an increase in ERE-driven gene expression in reporter assays. We identify altered methylation as a novel mechanism of BPA-induced altered developmental programming. Permanent epigenetic alteration of ERE sensitivity to estrogen may be a general mechanism through which endocrine disruptors exert their action.

Effect of atmosphere and catalyst on reducing bisphenol A (BPA) emission during thermal degradation of polycarbonate

Bisphenol A (BPA), a well-known endocrine disruptor, is one of the major products in the thermal degradation of polycarbonate (PC) and is also leached out from various PC products. Because of the high acute toxicity of BPA, reducing BPA production during degradation of PC is an important topic. A combined Infrared Image Furnace with Ion attachment mass spectrometry technique was used to investigate the evolution of BPA from a PC sample during heating in either nitrogen or air atmosphere and with or without a CuCl(2) catalyst. Thermal treatment in the presence of CuCl(2), in nitrogen atmospheres and at lower degradation temperatures, substantially reduced the BPA emission.

Bisphenol-A and disparities in birth outcomes: a review and directions for future research

Racial disparities in pregnancy outcome in the United States are significant, persistent and costly, but the causes are poorly understood. We propose that disproportionate exposure of African-American women to environmental endocrine disrupting compounds (EDCs) may contribute to birth outcome disparities. Marked racial segregation, as well as health behaviors associated with poverty could result in differences in exposure to particular EDCs. One EDC that has aroused concern in recent years is bisphenol-A (BPA), a widely used industrial plasticizer with known estrogenic properties. Published studies indicate that excessive BPA exposure is associated with reduced fetal survival, as well as reductions in maternal weight and fetal body weight. Related findings include adverse effects of BPA exposure on ovarian function, mammary gland development, earlier age of puberty onset and some metabolic parameters. However, these findings are largely limited to experimental animal studies, and need to be validated in human populations. Our review supports the need to move beyond the currently dominant toxicological approach to examining the effects of BPA exposure, and rely more on observational human studies and epidemiological methods. Many of the risk factors for racial disparities in pregnancy outcome are global or difficult to modify, but exposure to BPA is a potentially malleable risk factor. If BPA contributes to racial disparities in pregnancy outcome, there are important implications for prevention. It is our hope that this review will stimulate further research in this important and neglected area.

Potential risk of bisphenol A migration from polycarbonate containers after heating, boiling, and microwaving

The migration levels of bisphenol A (BPA) were analyzed in food samples by high-performance liquid chromatography (HPLC) from polycarbonate (PC) bottles subjected to simulated use by heating with microwave, heating in a boiling water bath, or filling them with boiling hot water (100 degrees C). Migration testing performed in PC bottles filled with steamed rice or hot cooked pork, standing at room temperature, or heated in a boiling water bath (100 degrees C) showed that BPA was not detected at the limit of detection (LOD) of 1 microg/L (ppb). In contrast, heating by microwaving to 100 degrees C for 9 min increased BPA migration levels from 6 to 18 ppb and from 5 to 15 ppb for steamed rice or for cooked pork, respectively. In addition, 3 different PC bottles were tested by filling them with boiling hot water (100 degrees C) and leaving them to stand at room temperature for up to 3 h. The mean BPA levels from the bottles increased in a time-dependent manner, with the range of not detected (ND) to 2.5 ppb after 60 min. However, none of the PC bottles released BPA at levels that exceed the recently established specific migration limits (SML) of 600 ppb established by European Union and Korea Food and Drug Administration (KFDA). Data suggest that the use of PC plastic bottles in our daily life is considered safe in Korea.

Cleaning and sterilisation of infant feeding equipment: a systematic review

Aim

To assess the clinical and cost-effectiveness of different methods of cleaning and sterilisation of infant feeding equipment used in the home.

Design

Systematic review of studies from developed countries on the effectiveness of methods of cleaning and sterilisation of infant feeding equipment used in the home. A brief telephone survey of UK-based manufacturers of infant feeding equipment and formula to ascertain the evidence base used for their recommendations, and a comparison of current relevant guidelines in developed countries, informed the work.

Results

National guidelines from six countries demonstrated variation and lack of evidence to support current guidance. Manufacturers did not report evidence of effectiveness to support their recommendations. Nine studies were identified; eight conducted between 1962 and 1985 and one in 1997. All had methodological weaknesses. Hand-washing was identified as fundamentally important. Health professionals were reported as not providing appropriate education on the importance and methods of cleaning and sterilisation. Mothers of subsequent babies and women from lower socio-economic groups were less likely to follow recommended procedures.

Conclusion

There is a lack of good-quality evidence on effective ways of cleaning and sterilising infant feeding equipment in the home. The evidence base does not answer the question about which of the methods in common use is most effective or most likely to be used by parents. Hand-washing before handling feeding equipment remains important. Further research on the range of methods used in the home environment, including assessment of the views of parents and carers, is required.

Migration of bisphenol A from polycarbonate baby and water bottles into water under severe conditions

The isotope dilution headspace solid-phase microextraction and gas chromatography-mass spectrometry method for bisphenol A (BPA) developed previously was used successfully in a BPA migration study at 70 degrees C of polycarbonate baby and reusable water bottles recently sold in Canada by using the whole bottles instead of pieces cut from the bottles. Migration of BPA from the PC bottles heated at 70 degrees C was found to increase over the time in the quadratic equations. Migration levels of BPA in water varied from 228 to 521 microg L (-1) or from 0.26 to 0.90 microg cm (-2) after being heated at 70 degrees C for 6 days. The average migration rates of BPA from the PC bottles into water at 70 degrees C ranged from 1.84 to 4.83 ng cm (-2) h (-1).

Bisphenol A is released from polycarbonate drinking bottles and mimics the neurotoxic actions of estrogen in developing cerebellar neurons

The impact of endocrine disrupting chemical (EDC) exposure on human health is receiving increasingly focused attention. The prototypical EDC bisphenol A (BPA) is an estrogenic high-production chemical used primarily as a monomer for the production of polycarbonate and epoxy resins. It is now well established that there is ubiquitous human exposure to BPA. In the general population, exposure to BPA occurs mainly by consumption of contaminated foods and beverages that have contacted epoxy resins or polycarbonate plastics. To test the hypothesis that bioactive BPA was released from polycarbonate bottles used for consumption of water and other beverages, we evaluated whether BPA migrated into water stored in new or used high-quality polycarbonate bottles used by consumers. Using a sensitive and quantitative competitive enzyme-linked immunosorbent assay, BPA was found to migrate from polycarbonate water bottles at rates ranging from 0.20 ng/h to 0.79 ng/h. At room temperature the migration of BPA was independent of whether or not the bottle had been previously used. Exposure to boiling water (100 degrees C) increased the rate of BPA migration by up to 55-fold. The estrogenic bioactivity of the BPA-like immunoreactivity released into the water samples was confirmed using an in vitro assay of rapid estrogen signaling and neurotoxicity in developing cerebellar neurons. The amounts of BPA found to migrate from polycarbonate drinking bottles should be considered as a contributing source to the total "EDC-burden" to which some individuals are exposed.

Human exposure to bisphenol A (BPA)

The plastic monomer and plasticizer bisphenol A (BPA) is one of the highest volume chemicals produced worldwide. BPA is used in the production of polycarbonate plastics and epoxy resins used in many consumer products. Here, we have outlined studies that address the levels of BPA in human tissues and fluids. We have reviewed the few epidemiological studies available that explore biological markers of BPA exposure and human health outcomes. We have examined several studies of levels of BPA released from consumer products as well as the levels measured in wastewater, drinking water, air and dust. Lastly, we have reviewed acute metabolic studies and the information available about BPA metabolism in animal models. The reported levels of BPA in human fluids are higher than the BPA concentrations reported to stimulate molecular endpoints in vitro and appear to be within an order of magnitude of the levels needed to induce effects in animal models.

Sensitive gas chromatographic–mass spectrometric method for the determination of phthalate esters, alkylphenols, bisphenol A and their chlorinated derivatives in wastewater samples

Phthalate esters, alkylphenols, bisphenol A and their chlorinated derivatives are the suspected endocrine disrupters or mutagens. These compounds, commonly called endocrine disrupter chemicals (EDCs), are widely used as plastic additives, lacquers, resins, or surfactants and can be usually found in environmental samples, namely wastewaters. An accurate and reproducible gas chromatographic-mass spectrometric (GC-MS) method is proposed to measure these compounds in wastewater samples of Granada city (Spain). A solid-phase extraction with LiChrolut RP-18 cartridges was carried out and the elution was performed with a diethyl ether/methanol mixture. After isolation, solvent was removed and a silylation step was carried out using N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA). Phthalate esters and silylated compounds were identified and quantified by GC-MS using a ZB-5 MS column. Bisphenol F was used as a surrogate. Quantification limits found were between 20 ng L(-1) for 4-nonylphenol and 400 ng L(-1) for benzylbutyl phthalate while inter and intra-day variability was under 5% in all cases. Recoveries for spiked samples were over 95% and under 105%. The method was validated using standard addition calibration and recovery assays.

Developmental and triiodothyronine-induced expression of genes encoding preprotemporins in the skin of Tago's brown frog Rana tagoi

Using RT-PCR, two cDNAs encoding preprotemporins were cloned from a total RNA preparation of the skin of Tago's brown frog Rana tagoi. Preprotemporin-1TGa cDNA directs the synthesis of temporin-1TGa (FLPILGKLLSGIL.NH2) previously isolated from R. tagoi skin. Preprotemporin-1TGb cDNA directs the synthesis of a novel 16-amino-acid-residue peptide (AVDLAKIANKVLSSLF.NH2) that, atypically for members of the temporin family, inhibits the growth of Gram-negative bacteria more effectively than Gram-positive bacteria. Preprotemporin-1TGa mRNA and preprotemporin-1TGb mRNA were not detected in skin prior to the onset of metamorphosis (stage 35) but the levels of the transcripts increased markedly during metamorphosis reaching a maximum at stage 38. Exposure of adult animals to 10(-8) M triiodothyronine (T3) for 72 h enhanced expression of the preprotemporin-1TGb gene (approximately threefold) but did not significantly change the level of expression of the preprotemporin-1TGa gene. Exposure of the animals to 10(-8) M T3 and 10(-6) M bisphenol A, an endocrine disrupting chemical that potently inhibits the action of thyroid hormones (THs), reduced expression of the preprotemporin-1TGb gene by 10-fold and the preprotemporin-1TGa gene by threefold. We propose that T3-stimulated synthesis of antimicrobial peptides is important in protecting the animal against microorganisms, particularly at metamorphosis and during skin moulting, but environmental pollutants can inhibit peptide synthesis and render the animal susceptible to invasion by pathogens.

High-performance liquid chromatographic analysis of bisphenol A and 4-nonylphenol in serum, liver and testis tissues after oral administration to rats and its application to toxicokinetic study

A sensitive and simple method based on solid-phase extraction (SPE) and HPLC with fluorescence detection for the determination of bisphenol A (BPA) and 4-nonylphenol (4-NP) in rat serum, liver and testis tissues has been developed. The chromatographic conditions consisted of a C18 column and mobile phase composition of acetonitrile and water with flow rate of 1.0 ml/min. The fluorescence detection was performed at excitation and emission wavelengths of 227 nm and 313 nm, respectively. Under these conditions, BPA and 4-NP were well separated and showed good linearities in the ranges of 0.01-50.0 microg/ml for BPA and 0.15-150.0 microg/ml for 4-NP with correlation coefficients greater than 0.999. The detection limits of serum and tissue samples were 2.8 ng/ml and 1.4 ng/g for BPA and 5.6 ng/ml and 2.8 ng/g for 4-NP at a signal-to-noise ratio (S/N) of 3. The intra-assay and the inter-assay precisions were better than 11.4%. Recoveries of BPA and 4-NP were 78.6-95.0% and 80.2-93.4%, respectively. The proposed method was applied to a toxicokinetic study of BPA and 4-NP including individual and combined oral administration to rats. The results showed that 4-NP remarkably altered the toxicokinetic parameters of BPA in testis, while parameters of BPA were not obviously altered in serum and liver under the experimental conditions investigated. On the other hand, there was no significant difference in the toxicokinetics of 4-NP when administered with BPA.

Evaluation of androgen receptor transcriptional activities of bisphenol A, octylphenol and nonylphenol in vitro

In this study, we have developed a human androgen receptor (hAR) reporter gene assay using African monkey kidney cell line CV-1 transiently transfected with the constructed reporter gene plasmid pMMTV-CAT and the hAR expression plasmid AR/pcDNA3.1. The assay displayed appropriate response to the known AR agonist 5alpha-dihydrotestosterone (DHT) and AR antagonist flutamide. DHT induced AR-mediated transcriptional activity in a concentration-dependent manner with median effective concentration (EC50) value of (3.90+/-1.43)x10(-10)M. Flutamide exhibited potent antiandrogenic activity with median inhibitory concentration (IC50) value of (1.02+/-0.35)x10(-7)M. Bisphenol A (BPA) and alkylphenols (APs) belong to the industrial chemicals that have received considerable attention due to high production and widespread usage. We investigated BPA, 4-octylphenol (OP) and 4-nonylphenol (NP) for their agonistic and antagonistic activities by the AR reporter gene assay. BPA showed significant inhibitory effects on the transcriptional activity induced by DHT with IC50 value of (7.46+/-1.23)x10(-7)M. OP and NP exhibited lower antiandrogenic activities than BPA with IC(50) of (9.71+/-3.82)x10(-5)M and (2.02+/-0.90)x10(-5)M, respectively. On the other hand, we failed to find AR-mediated androgenic activities of the three tested chemicals. In conclusion, BPA, OP and NP all act as AR antagonists, and BPA possesses the highest activity.