In vitro effect of the resin component bisphenol A on substrate adherence capacity of macrophages

Persistent immunosuppressive effects of dibutyl phthalate exposure in adult male mice

Increased exposure to manmade chemicals may be linked to an increase in immune-related diseases in humans and immune system dysfunction in wildlife. Phthalates are a group of endocrine-disrupting chemicals (EDCs) suspected to influence the immune system. The aim of this study was to characterize the persistent effects on leukocytes in the blood and spleen, as well as plasma cytokine and growth factor levels, one week after the end of five weeks of oral treatment with dibutyl phthalate (DBP; 10 or 100 mg/kg/d) in adult male mice. Flow cytometry analysis of the blood revealed that DBP exposure decreased the total leukocyte count, classical monocyte and T helper (Th) populations, whereas it increased the non-classical monocyte population compared to the vehicle control (corn oil). Immunofluorescence analysis of the spleen showed increased CD11b⁺Ly6G⁺ (marker of polymorphonuclear myeloid-derived suppressor cells; PMN-MDSCs), and CD43⁺staining (marker of non-classical monocytes), whereas CD3⁺ (marker of total T cells) and CD4⁺ (marker of Th cells) staining decreased. To investigate the mechanisms of action, levels of plasma cytokines and chemokines were measured using multiplexed immunoassays and other key factors were analyzed using western blotting. The observed increase in M-CSF levels and the activation of STAT3 may promote PMN-MDSC expansion and activity. Increased ARG1, NOX2 (gp91phox), and protein nitrotyrosine levels, as well as GCN2 and phosphor-eIRFα, suggest that oxidative stress and lymphocyte arrest drive the lymphocyte suppression caused by PMN-MDSCs. The plasma levels of IL-21 (promotes the differentiation of Th cells) and MCP-1 (regulates migration and infiltration of monocytes/macrophages) also decreased. These findings show that adult DBP exposure can cause persistent immunosuppressive effects, which may increase susceptibility to infections, cancers, and immune diseases, and decrease vaccine efficacy.

Reattachment of Fractured Tooth Fragment by Multidisciplinary Treatment Approach

Dental anterior fractures are common injuries, especially in those who practice extreme sports. This report describes a 25-year-old Bolivian patient who attended our private dental clinic in La Paz, Bolivia after experiencing an accident during downhill mountain biking. An intraoral examination revealed a fracture line on the buccal side in the middle third of the coronal portion of the right central maxillary incisor which extended towards the proximal and lingual sides. Multidisciplinary treatment, including crown lengthening, osteotomy, root canal treatment, fiberglass post insertion, and reattachment of the fracture segment was performed. A follow-up examination at 10 months later revealed that the tooth was completely reestablished both functionally and esthetically and that there was no periapical pathosis or discomfort. This outcome suggests that if a patient seeks a dental consultation soon after a complex crown-root fracture has occurred, and if the broken tooth segment is available, then reattachment offers an economical and simple treatment option which will allow immediate restoration of functionality and esthetic standards. Continued follow-up should form part of such a treatment plan to allow long-term pulp vitality and periodontal health status to be monitored.

EDC-induced mechanisms of immunotoxicity: a systematic review

Endocrine-disrupting chemicals (EDCs) refer to a group of chemicals that cause adverse effects in human health, impairing hormone production and regulation, resulting in alteration of homeostasis, reproductive, and developmental, and immune system impairments. The immunotoxicity of EDCs involves many mechanisms altering gene expression that depend on the activation of nuclear receptors such as the aryl hydrocarbon receptor (AHR), the estrogen receptor (ER), and the peroxisome proliferator-activated receptor (PPAR), which also results in skin and intestinal disorders, microbiota alterations and inflammatory diseases. This systematic review aims to review different mechanisms of immunotoxicity and immunomodulation of T cells, focusing on T regulatory (Treg) and Th17 subsets, B cells, and dendritic cells (DCs) caused by specific EDCs such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), bisphenols (BPs) and polyfluoroalkyl substances (PFASs). To achieve this objective, a systematic study was conducted searching various databases including PubMed and Scopus to find in-vitro, in-vivo, and biomonitoring studies that examine EDC-dependent mechanisms of immunotoxicity. While doing the systematic review, we found species- and cell-specific outcomes and a translational gap between in-vitro and in-vivo experiments. Finally, an adverse outcome pathway (AOP) framework is proposed, which explains mechanistically toxicity endpoints emerging from different EDCs having similar key events and can help to improve our understanding of EDCs mechanisms of immunotoxicity. In conclusion, this review provides insights into the mechanisms of immunotoxicity mediated by EDCs and will help to improve human health risk assessment.

Cytotoxicity of two self-adhesive resin cements and their interference in the phagocytic activity of murine macrophages

Objectives

This study aimed to evaluate in vitro the effects of the self-adhesive resin cements RelyX U200 (3M ESPE) and seT PP (SDI Limited) on murine macrophages and the interference of the photoactivation.

Materials and Methods

Cell viability assays, cell adherence, yeast phagocytosis of Saccharomyces boulardii and production of reactive oxygen species (ROS) were performed in the presence of capillaries containing the respective self-adhesive cement when photoactivated or not.

Results

After long periods of contact, both types of cements, when not photoactivated, are more cytotoxic for macrophages. The seT PP cement when only chemically activated seems to interfere more negatively in the process of phagocytosis of yeasts S. boulardii. Both types of cements interfere in the cell adhesion process, independent of photoactivation. None of the types of cements tested was able to induce the production of ROS.

Conclusions

Our results highlight the great importance of the photoactivation of self-adhesive resin cements in the dental clinic, since RelyX U200, when photoactivated, presented the best results within the evaluated parameters.

Immune Cells in the Uterine Remodeling: Are They the Target of Endocrine Disrupting Chemicals?

Sufficient uterine remodeling is essential for fetal survival and development. Pathologies related to poor remodeling have a negative impact on maternal and fetal health even years after birth. Research of the last decades yielded excellent studies demonstrating the key role of immune cells in the remodeling processes. This review summarizes the current knowledge about the relevance of immune cells for uterine remodeling during pregnancy and further discusses immunomodulatory effects of man-made endocrine disrupting chemicals on immune cells.

Neurochemical characterization of the enteric neurons within the porcine jejunum in physiological conditions and under the influence of bisphenol A (BPA)

BACKGROUND

Bisphenol A (BPA) is commonly used in the production of plastics and has multidirectional, negative effects on the living organisms. It may also affect the enteric nervous system (ENS) located in the wall of the gastrointestinal tract. Enteric neurons express many active substances, which regulate majority of intestinal activities not only in physiological conditions but also under the impact of pathological factors.

METHODS

The influence of various doses of BPA on the ENS of jejunum has been investigated using the double immunofluorescence technique. The commercial antibodies against substance P (SP), vasoactive intestinal polypeptide (VIP), galanin (GAL), vesicular acetylcholine transporter (VAChT), and cocaine- and amphetamine-regulated transcript peptide (CART) were used.

KEY RESULTS

Both doses of BPA studied changed the number of the enteric neurons immunoreactive to SP, VIP, GAL, VAChT, and CART, and the intensity of fluctuations depended on the BPA dose and on the type of the enteric plexus. Bisphenol A causes the increase in the number of neurons immunoreactive to the majority of substances studied. The only exception was VAChT-positive neurons, the number of which was lower under the impact of BPA in the comparison with physiological conditions.

CONCLUSIONS & INFERENCES

Even low doses of BPA cause the changes in neurochemical characterization of the enteric neurons in the jejunum. These changes may be the first sign of subclinical BPA intoxication. The mechanisms of observed changes are probably connected with neurotoxic and/or pro-inflammatory activity of BPA, but their exact mechanisms are not fully explained.

Bisphenol A Promotes the Invasive and Metastatic Potential of Ductal Carcinoma In Situ and Protumorigenic Polarization of Macrophages

Increased cancer risk and immune disorders linked with exposure to environmental endocrine disruptors like bisphenol A (BPA) have been steadily reported. Nevertheless, the impacts of BPA on the breast ductal carcinoma in situ (DCIS) progression and macrophage polarization remain to be elucidated. Here, we analyzed the differentially expressed genes in BPA-exposed DCIS cells and explored BPA effects on DCIS progression and macrophage polarization in vitro and in vivo. Two hundred and ninety-one genes were differentially expressed in 10−8 M BPA-exposed DCIS cells, in which the gene ontology terms of biological processes associated with negative regulation of cell death, cell adhesion, and immune response was enriched. 10−8 M BPA promoted the proliferation and migration of DCIS cells and the migration of macrophages, and upregulated the expression of M1 (NOS2) or M2 markers (Arg-1 and CD206) in macrophages. In coculture system, the migratory capacity of both cells and the expression levels of NOS2, Arg-1, and CD206 in macrophages were significantly enhanced upon 10−8 M BPA. In a DCIS xenograft model, oral exposure to an environmentally human-relevant low dose of 2.5 µg/l BPA for 70 days via drinking water led to an approximately 2-fold promotion in the primary tumor growth rate and a significant enhancement of lymph node metastasis along with increased protumorigenic CD206+ M2 polarization of macrophages. These results demonstrate that BPA acts as an accelerator to promote DCIS progression to invasive breast cancer by affecting DCIS cell proliferation and migration as well macrophage polarization toward a protumorigenic phenotype.

Immunomodulatory effects of synthetic endocrine disrupting chemicals on the development and functions of human immune cells

Endocrine disrupting chemicals (EDCs) are added to food, cosmetics, plastic packages, and children's toys and have thus become an integral part of the human environment. In the last decade, there has been increasing interest in the effect of EDCs on human health, including their impact on the immune system. So far, researchers have proved that EDCs (e.g. bisphenols, phthalates, triclosan, phenols, propanil, tetrachlorodibenzo-p-dioxin, diethylstilbestrol, tributyltin (TBT), and parabens) affect the development, functions, and lifespan of immune cells (e.g., monocytes, neutrophils, mast cells, eosinophils, lymphocytes, dendritic cells, and natural killers). In this review, we have summarized the current knowledge of the multivariable influence of EDCs on immune cells and underlined the novel approach to EDC studies, including dose-dependent effects and low-dose effects. We discuss critically the possible relationship between exposure to EDCs and immunity related diseases (e.g. allergy, asthma, diabetes, and lupus). Moreover, based on the literature, we construct a model of possible mechanisms of EDC action on immune cells at cellular, molecular, and epigenetic levels.

Interruption of immune responses in primary macrophages exposed to nonylphenol provides insights into the role of ER and NF-KB in immunotoxicity of Persian sturgeon

The severe decline in population of sturgeons due to pollution highlighted poor understanding about the immunotoxicological responses of sturgeons. This study was designed in three experiments to find out how nonylphenol (NP) interrupts some pro-inflammatory immune parameters in macrophages from Persian sturgeon (Acipencer persicous) as the oldest vertebrate model conserving intact innate immune system. After determination of IC₅₀ values of NP (200 μM), some pro-inflammatory immune parameters and induced apoptosis in macrophages at low dose (10 nM) and high dose (100 nM) of NP and of 17β estradiol (E2) (positive control) were determined after 6, 24 and 48 h of the exposure (as the first experiment). The two doses of NP induced pro-inflammatory reaction and apoptosis with strong correlations, whereas this result was observed more obviously in high dose of E2. In the second experiments, the macrophages were exposed to the two doses of NP along with estrogen receptor alpha (ERα) antagonist, which consequently decreased the induction of pro-inflammatory reactions. Similarly, in the third experiment, NF-KB and ERα antagonists were used and pro-inflammatory reactions decreased compared to the control group (P < 0.05). Decreasing correlation between immune parameters following the second and third experiments verified interaction between ERα and NF-KB pathways. Thus, NP could be immune disrupter and apoptosis inducer in sturgeon macrophages in vitro, even in low dose. For the first time, this study revealed that NP can induce pro-inflammatory reactions in macrophages derived from sturgeons.

The Neurochemical Characterization of Parasympathetic Nerve Fibers in the Porcine Uterine Wall Under Physiological Conditions and After Exposure to Bisphenol A (BPA)

Bisphenol A, a substance commonly used in plastic manufacturing, is relatively well known as an endocrine disruptor, which may bind to estrogen receptors and has multidirectional negative effects on both human and animal organisms. Previous studies have reported that BPA may act on the reproductive organs, but knowledge concerning BPA-induced changes within the nerves located in the uterine wall is extremely scant. The aim of this study was to investigate the impact of various doses of BPA on the parasympathetic nerves located in the corpus and horns of the uterus using a single and double immunofluorescence method. The obtained results have shown that BPA may change not only the expression of vesicular acetylcholine transporter (VAChT—a marker of parasympathetic nervous structures) in the uterine intramural nerve fibers, but also the degree of colocalization of this substance with other neuronal factors, including substance P (SP), vasoactive intestinal polypeptide (VIP), galanin (GAL), and calcitonin gene–related peptide (CGRP). Moreover, BPA caused changes in the density of the overall populations of fibers immunoreactive to the particular neuropeptides mentioned above. The characteristics of the changes clearly depended on the part of the uterus, the neuronal factors studied, and the dosage of BPA. The mechanisms of the observed fluctuations are probably connected with the neurotoxic and/or pro-inflammatory activity of BPA. Moreover, the results have shown that even low doses of BPA are not neutral to living organisms. Changes in the neurochemical characterization of nerves supplying the uterine wall may be the first subclinical sign of intoxication with this substance.

The effects of Bisphenol A (BPA) on sympathetic nerve fibers in the uterine wall of the domestic pig

Bisphenol A (BPA), used in the production of plastic, shows multidirectional negative effects on the living organism. BPA may affect the reproductive and nervous systems; however, its influence on the nerves supplying the uterus has not been studied. During the present study, the impact of BPA on the sympathetic nerves in the uterus was investigated using a double immunofluorescence technique. The results have shown that even low doses of BPA may change the neurochemical characterization of uterine sympathetic nerves, and the severity of these changes depends on the part of the uterus and the dose of the toxic substance. Probably the changes observed during the present study resulted from the neurotoxic and/or pro-inflammatory activity of BPA, but the exact mechanism for the observed fluctuation still remains unknown. The fluctuations of the neurochemical characterization of the uterine intramural nerves may be the first subclinical signs of harmful exposure to BPA.

Nitric oxide as an active substance in the enteric neurons of the porcine digestive tract in physiological conditions and under intoxication with bisphenol A (BPA)

Bisphenol A (BPA) is an organic substance, which is commonly used in the production of plastic. It is known that BPA has the negative impact on the living organism, affecting among others the reproductive organs, nervous, endocrine and immune systems. Nevertheless the knowledge about the influence of BPA on the enteric nervous system (ENS) is extremely scanty. On the other hand, nitric oxide is considered to be one of the most important neuronal factors in the ENS. The aim of the study was to investigate the influence of low and high doses of BPA on neuronal isoform nitric oxide synthase - like immunoreactive (nNOS-LI) nervous structures in the various parts of the porcine gastrointestinal (GI) tract using double immunofluorescence technique. The obtained results show that BPA affects nNOS-LI enteric neurons and nerve fibers, and the character and severity of observed changes depend on the fragment of the gastrointestinal tract, part of the ENS and dose of the toxin. It should be pointed out that even relatively low doses of BPA (0.05 mg/kg body weight/day) are not neutral for the organism and may change the number of nitrergic nervous structures in the stomach and intestine. Observed changes are probably connected with neurotoxic activity of BPA, but the exact mechanisms of them still remain unclear.

From the Cover: Lifelong Exposure of C57bl/6n Male Mice to Bisphenol A or Bisphenol S Reduces Recovery From a Myocardial Infarction

Bisphenol A (BPA) leaches from plastics to contaminate foodstuffs. Analogs, such as bisphenol S (BPS), are now used increasingly in manufacturing. Greater BPA exposure has been correlated with exacerbation of cardiovascular disease, including myocardial infarction (MI). To test the hypothesis that bisphenol exposure impairs cardiac healing, we exposed C57bl/6n mice to water containing 25ng/ml BPA or BPS from conception and surgically induced an MI in adult male progeny. Increased early death and cardiac dilation, and reduced cardiac function were found post-MI in BPA- and BPS-exposed mice. Flow cytometry revealed increased monocyte and macrophage infiltration that correlated with increased chemokine C-C motif ligand-2 expression in the infarct. In vitro BPA and BPS addition increased matrix metalloproteinase-9 (MMP) protein and secreted activity in RAW264.7 macrophage cells suggesting that invivo increases in MMP2 and MMP9 in exposed infarcts were myeloid-derived. Bone marrow-derived monocytes isolated from exposed mice had greater expression of pro-inflammatory polarization markers when chemokine stimulated indicating an enhanced susceptibility to develop a pro-inflammatory monocyte population. Chronic BPA exposure of estrogen receptor beta (ERβ) deficient mice did not worsen early death, cardiac structure/function, or expression of myeloid markers after an MI. In contrast, BPS exposure of ERβ-deficient mice resulted in greater death and expression of myeloid markers. We conclude that lifelong exposure to BPA or BPS augmented the monocyte/macrophage inflammatory response and adverse remodeling from an MI thereby reducing the ability to survive and successfully recover, and that the adverse effect of BPA, but not BPS, is downstream of ERβ signaling.

The Influence of High and Low Doses of Bisphenol A (BPA) on the Enteric Nervous System of the Porcine Ileum

Bisphenol A, used in the production of plastic, is able to leach from containers into food and cause multidirectional adverse effects in living organisms, including neurodegeneration and metabolic disorders. Knowledge of the impact of BPA on enteric neurons is practically non-existent. The destination of this study was to investigate the influence of BPA at a specific dose (0.05 mg/kg body weight/day) and at a dose ten times higher (0.5 mg/kg body weight/day), given for 28 days, on the porcine ileum. The influence of BPA on enteric neuron immunoreactive to selected neuronal active substances, including substance P (SP), vasoactive intestinal polypeptide (VIP), galanin (GAL), vesicular acetylcholine transporter (VAChT—used here as a marker of cholinergic neurons), and cocaine- and amphetamine-regulated transcript peptide (CART), was studied by the double immunofluorescence method. Both doses of BPA affected the neurochemical characterization of the enteric neurons. The observed changes depended on the type of enteric plexus but were generally characterized by an increase in the number of cells immunoreactive to the particular substances. More visible fluctuations were observed after treatment with higher doses of BPA. The results confirm that even low doses of BPA may influence the neurochemical characterization of the enteric neurons and are not neutral for living organisms.

Dietary soy isoflavones during pregnancy suppressed the immune function in male offspring albino rats

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Less attention has been paid to the immune effects of phytoestrogens during pregnancy on the first generation.

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Soy isoflavones fed to pregnant rats could modulate the immune response of the male offspring.

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Isoflavones reduced spleen and thymus weights in rats born to dams fed dietary soy.

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Soy isoflavones possibly mediated its effect through reduction of IFN-γ that interacts with the IL-12 production pathway.

Phytoestrogens have an impact on both animals and humans due to use of legumes in animal diets as well as the increase of vegetarian diets in some human populations. Phytoestrogens thought to have varieties of adverse effects, among which immune system was involved. The present study aimed to investigate the effect of prenatal exposure to dietary soy isoflavones on some immunological parameters in male albino rat offspring. The pregnant rats were divided to three groups (12/group). Control group (free soy isoflavones), low soy isoflavones group (6.5%) and high soy isoflavones group (26%). The male offspring cell-mediated immune response was determined using phytohemagglutinin (PHA) injection and the intumesce index which was calculated on postnatal day 50 (PND 50). At PND 50, blood samples were collected for interleukin 12 (IL-12), interferon γ (IFN-γ) and tumor necrosis factor α (TNF-α) determination. Spleen, thymus, and PHA injected footpads were fixed for histopathology. Intumesce index, IL-12, IFN-γ, spleen and thymus relative weights were significantly (P < 0.05) decreased in offspring born to dams fed low and high dietary soy isoflavones. In contrary, TNF-α was significantly (P < 0.05) increased in offspring born to dams fed high dietary soy isoflavones. Spleen of rats born to dams fed high dose of dietary soy isoflavones showed coagulative necrosis in white pulp. In conclusion, male offspring born to dams fed different levels of soy isoflavones showed marked immunosuppression after PHA stimulation. This effect was mediated through the reduced IFN-γ that interacts with the IL-12 production pathway.

Extrusion of Root Canal Sealer in Periapical Tissues - Report of Two Cases with Different Treatment Management and Literature Review

Background: Extrusion of root canal sealers may cause damage to the surrounding anatomic structures. Clinical symptoms like pain, swelling and paresthesia or anesthesia may be present. The purpose of this presentation is to describe two cases of root canal sealer penetration into periapical tissues. A different treatment management was followed in each case.

Case reports: A 55 year-old man underwent root canal retreatment of the right mandibular first molar tooth due to a periapical lesion. Postoperative periapical radiographs revealed the presence of root canal sealer (AH26) beyond the apex in the distal root in proximity to the mandibular canal. The patient reported pain for the next 7 days. Radiographic examination after 1 year showed complete healing of the periapical area and a small absorption of the root canal sealer. A 42 year-old woman was referred complained of swelling and pain in the area of the right maxillary first incisor. Radiographic examination showed extrusion of root canal sealer in the periapical area associated with a periapical lesion. Surgical intervention was decided upon, which included removal of the sealer, apicoectomy of the tooth and retrograde filling with MTA. After 1 year, complete healing of the area was observed.

Conclusion: In conclusion, cases of root canal sealer extrusion, surgical treatment should be decided on only in association with clinical symptoms or with radiographic evidence of increasing periapical lesion.

The Association of Serum Bisphenol A with Thyroid Autoimmunity

Introduction: Data on the association of bisphenol A (BPA) exposure and autoimmunity in humans is unclear. Objective: To elucidate the influence of BPA on thyroid autoimmunity, in the present study we assessed the association between serum BPA and thyroid autoantibodies. Methods: Serum samples from 2361 subjects, aged ≥15 years, from the Thai 4th National Health Examination Survey were measured for BPA, antithyroglobulin (TgAb), antithyroperoxidase (TPOAb) and antithyrotrophin receptor (TRAb) antibodies. Results: The proportion of subjects positive for TgAb, TPOAb and TRAb were 11.1%, 14.9% and 1.9%, respectively. With regard to BPA, 51.9% had serum BPA levels exceeding the detection limit of the assay (0.3). There was a significant increasing trend for subjects with TgAb (p < 0.05) and TPOAb (p < 0.001) positivity as BPA quartiles increased, particularly in the highest quartile. In contrast, no relationship between BPA quartiles and TRAb was found. Logistic regression analysis showed that age, gender and BPA quartiles were determinants of TPOAb or TgAb positivity, independent of BMI. However, only the association between BPA and TPOAb positivity was consistent in both men and women. Conclusions: BPA was independently associated with TPOAb positivity. However, its mechanism related to TPOAb positivity, subsequently leading to autoimmune thyroid disease, needs further investigation.

Effects of xenoestrogens in human M1 and M2 macrophage migration, cytokine release, and estrogen-related signaling pathways

Bisphenol A (BPA), bis(2-ethylhexyl)phthalate (DEHP) and di(n-butyl)phthalate (DBP) are environmental estrogens that have been associated with a wide range of adverse health outcomes for which inflammation has also been hypothesized as a potentially involved mechanism and where macrophages play a central role. This study was carried out to evaluate if xenoestrogen (XE) treatment of classically (M1) or alternatively (M2) activated macrophages could affect their behavior. For this purpose, human peripheral blood monocyte-derived macrophages either unstimulated or activated with lipopolysaccharide (100 ng/mL, M1) or with interleukin (IL) 4 (15 ng/mL, M2) were treated with 17β-estradiol (E₂ ), BPA, DEHP and DBP alone or in combination with selective ERα or ERβ antagonists. Migratory capability, cytokine release, and estrogen-associated signaling pathways were evaluated to assess macrophage function. All tested XEs had a tendency to stimulate M2 migration, an effect that followed the same direction than E₂ . Moreover, all XEs significantly induced IL10 in M1 and decreased IL6 and globally decreased IL10, IL6, TNFα, and IL1β release by M2 macrophages. However, DEHP and DBP significantly increased IL1β release in M1 and M2 macrophages, respectively. Some of the effects described above were shown to be mediated by either ERα or ERβ and were simultaneous to modulation of NF-κB, AP1, JNK, or ERK signaling pathways. We provide new evidence of the effect of XE on macrophage behavior and their mechanisms with relevance to the understanding of the action of environmental chemicals on the immune system and inflammation-associated diseases. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1496-1509, 2016.

Improvement of cytocompatibility of 3D-printing resins for endothelial cell adhesion

We developed a new method for improving the biocompatibility of 3D-printing photosensitive resins using waterborne polyurethane (WPU) as the coating material.

Environmental estrogen bisphenol A and autoimmunity

Over the past few years, there has been evidence of the increasing prevalence of autoimmune diseases. Autoimmune diseases consist of many complex disorders of unknown etiology resulting in immune responses to self-antigens. The immune system, and its function, is under complex and integrated control and its disruption can be triggered by multiple factors. Autoimmunity development is influenced by multiple factors and is thought to be a result of interactions between genetic and environmental factors. Here, we review the role of a specific environmental factor, bisphenol A (BPA), in the pathogenesis of autoimmune diseases. BPA belongs to the group of environmental estrogens that have been identified as risk factors involved in the development of autoimmune diseases.

Chronic Exposure to Bisphenol A Reduces Successful Cardiac Remodeling After an Experimental Myocardial Infarction in Male C57bl/6n Mice

Estrogenic compounds such as bisphenol A (BPA) leach from plastics into food and beverage containers. Increased BPA exposure has been correlated with increased cardiovascular disease. To test the hypothesis that increased BPA exposure reduces cardiovascular remodeling, we chronically exposed C57bl/6n male mice to BPA and performed a myocardial infarction (MI). We measured cardiac function, as well as myeloid and cardiac fibroblast accumulation and activity. We found increased early death as well as increased cardiac dilation and reduced cardiac function in surviving BPA-exposed mice. Matrix metalloproteinase-2 (MMP2) protein and activity were increased 1.5-fold in BPA-exposed heart. BPA-exposed mice had similar neutrophil infiltration; however, monocyte and macrophage (MΦ) infiltration into the ischemic area was 5-fold greater than VEH mice potentially due to a 2-fold increase in monocyte chemoattractant protein-1. Monocyte and MΦ exposure to BPA in vitro in primary bone marrow cultures or in isolated peritoneal MΦ increased polarization to an activated MΦ, increased MMP2 and MMP9 expression 2-fold and activity 3-fold, and increased uptake of microspheres 3-fold. Cardiac fibroblasts (CF) differentiate to α-smooth muscle actin (αSMA) expressing myofibroblasts, migrate to the ischemic area and secrete collagen to strengthen the scar. Collagen and αSMA expression were reduced 50% in BPA-exposed hearts. Chronic in vivo or continuous in vitro BPA exposure ablated transforming growth factor beta-mediated differentiation of CF, reduced αSMA expression 50% and reduced migration 40% yet increased secreted MMP2 activity 2-fold. We conclude that chronic BPA exposure reduces the ability to successfully remodel after an MI by increasing MΦ-based inflammation and reducing myofibroblast repair function.

Cytotoxic effect of silorane and methacrylate based composites on the human dental pulp stem cells and fibroblasts

Objectives: The aim of this study was to compare the cytotoxic effect of a methacrylate-based and a silorane-based composite on the human dental pulp stem cells (DPSCs) versus human dental pulp fibroblasts (DPFs). Study Design: Samples of the Filtek Z250 and P90 were polymerized and immersed in the culture medium to obtain extracts after incubation for one, seven and 14 days. Magnetic cell sorting based on the CD146 expression was performed to purify DPSCs and DPFs. After incubation of both cells with the extracts, cytotoxicity was determined using the MTT test. Results: For the extracts of first and seventh day, both composites showed significantly lower cytotoxicity on DPSCs than DPFs (p=0.003). In addition, there was a significant difference in the time-group interaction of both materials indicating different cytotoxic behaviours (p=0.014). In contrast to Z250, exposure to the 14th day extract of P90 resulted in higher cell viability compared to that of day seven. Conclusions: DPSCs are less susceptible to the cytotoxic effect of the composites than DPFs. Compared to Z250, the cytotoxic effect of silorane-based composite decreases as the time passes on. This difference should be considered, particularly in deep cavities, in order to preserve the regenerative capacity of the pulp.

Key words:Composite resins, Dental pulp, Mesenchymal Stromal Cells, Silorane, Toxicology.

Pregabalin in the treatment of inferior alveolar nerve paraesthesia following overfilling of endodontic sealer

A case of orofacial pain and inferior alveolar nerve (IAN) paraesthesia after extrusion of endodontic sealer within the mandibular canal treated with prednisone and pregabalin is described. A 36-year-old woman underwent root canal treatment of the mandibular second right premolar tooth. Post-operative panoramic radiograph revealed the presence of radiopaque canal sealer in the mandibular canal. Damage to IAN consecutive to extrusion of endodontic sealer was diagnosed. Non-surgical management was decided, including: 1 mg/kg/day prednisone 2 times/day, once-daily regimen, and 150 mg/day pregabalin, two doses per day, monitoring the progress with periodic follow-up visits. Six weeks after the incident the signs and symptoms were gone. The complete resolution of paraesthesia and the control of pain achieved suggest that a non-surgical approach, combining prednisone and the GABA analogue pregabalin, is a good option in the management of the IAN damage subsequent to endodontic sealer extrusion. Key words:Endodontics, inferior alveolar nerve, neuropathic pain, orofacial pain, paraesthesia, pregabalin.

Bisphenol A and human health: a review of the literature

There is growing evidence that bisphenol A (BPA) may adversely affect humans. BPA is an endocrine disruptor that has been shown to be harmful in laboratory animal studies. Until recently, there were relatively few epidemiological studies examining the relationship between BPA and health effects in humans. However, in the last year, the number of these studies has more than doubled. A comprehensive literature search found 91 studies linking BPA to human health; 53 published within the last year. This review outlines this body of literature, showing associations between BPA exposure and adverse perinatal, childhood, and adult health outcomes, including reproductive and developmental effects, metabolic disease, and other health effects. These studies encompass both prenatal and postnatal exposures, and include several study designs and population types. While it is difficult to make causal links with epidemiological studies, the growing human literature correlating environmental BPA exposure to adverse effects in humans, along with laboratory studies in many species including primates, provides increasing support that environmental BPA exposure can be harmful to humans, especially in regards to behavioral and other effects in children.

Inferior alveolar nerve injury resulting from overextension of an endodontic sealer: non-surgical management using the GABA analogue pregabalin

AIM

  To describe a case of endodontic sealer (AH Plus) penetration within the mandibular canal after root canal treatment with resolution of pain and paraesthesia after a non-surgical approach, including treatment with prednisone and pregabalin.

SUMMARY

  A 37-year-old woman underwent root canal treatment of the left mandibular second molar tooth. Postoperative periapical radiographs revealed the presence of radiopaque canal sealer in the mandibular canal. The day after, the patient reported severe pain in the tooth and paraesthesia/anaesthesia in the region innervated by the left inferior alveolar and mental nerve. Diagnosis of injury to the inferior alveolar nerve because of extrusion of AH Plus was established. The non-surgical management included 1 mg kg(-1) per day prednisone, two times per day, in a regimen on a daily basis, and 150 mg per day pregabalin, two doses per day, monitoring the progress with periodic follow-up visits. One month after the incident, the signs and symptoms were gone.

KEY LEARNING POINTS

This case illustrates the care required when performing root canal treatment, especially when the root apices are in close proximity to the inferior alveolar nerve canal. The complete resolution of paraesthesia and the control of pain achieved in the present case suggests that a non-surgical approach combining prednisone and pregabalin is a good option in the management of the inferior alveolar when it is contacted by extruded root filling material.

The impact of bisphenol A and triclosan on immune parameters in the U.S. population, NHANES 2003-2006

BACKGROUND

Exposure to environmental toxicants is associated with numerous disease outcomes, many of which involve underlying immune and inflammatory dysfunction.

OBJECTIVES

To address the gap between environmental exposures and immune dysfunction, we investigated the association of two endocrine-disrupting compounds (EDCs) with markers of immune function.

METHODS

Using data from the 2003-2006 National Health and Nutrition Examination Survey, we compared urinary bisphenol A (BPA) and triclosan levels with serum cytomegalovirus (CMV) antibody levels and diagnosis of allergies or hay fever in U.S. adults and children ≥ 6 years of age. We used multivariate ordinary least squares linear regression models to examine the association of BPA and triclosan with CMV antibody titers, and multivariate logistic regression models to investigate the association of these chemicals with allergy or hay fever diagnosis. Statistical models were stratified by age (< 18 years and ≥ 18 years).

RESULTS

In analyses adjusted for age, sex, race, body mass index, creatinine levels, family income, and educational attainment, in the ≥ 18-year age group, higher urinary BPA levels were associated with higher CMV antibody titers (p < 0.001). In the < 18-year age group, lower levels of BPA were associated with higher CMV antibody titers (p < 0.05). However, triclosan, but not BPA, showed a positive association with allergy or hay fever diagnosis. In the < 18-year age group, higher levels of triclosan were associated with greater odds of having been diagnosed with allergies or hay fever (p < 0.01).

CONCLUSIONS

EDCs such as BPA and triclosan may negatively affect human immune function as measured by CMV antibody levels and allergy or hay fever diagnosis, respectively, with differential consequences based on age. Additional studies should be done to investigate these findings.

Plant-originated glycoprotein (36 kDa) suppresses interleukin-4 and -10 in bisphenol A-stimulated primary cultured mouse lymphocytes

Bisphenol A (BPA) is one of the estrogen mimic environmental hormones and a chemical used for the wrapping foods, toy products for children, biomedical equipment, and machines. It can exert toxic effects, such as occurring allergy-related diseases. This study demonstrates that glycoprotein isolated from Rhus verniciflua Stokes (RVS glycoprotein) has an inhibitory activity of T-helper type 2 (Th2) cytokines [Interleukin (IL)-4 and -10]. First, it was shown that RVS glycoprotein inhibits the proliferation of lymphocytes and scavenges intracellular reactive oxygen species (ROS). Then, the activities of mitogen-activated protein kinase (MAPK), GATA-binding protein-3 (GATA-3), t-box expressed in T-cells (T-bet), and Th2 cell-related cytokine (IL-4 and -10) were evaluated in BPA (50 microM)-stimulated primary cultured mouse lymphocytes, using immunoblot analysis and reverse-transcription polymerase chain reaction (RT-PCR). The results showed that the RVS glycoprotein (50 microg/mL) inhibited the proliferation of lymphocytes, intracellular ROS, and activity of p38 MAPK dose dependently. In the transcriptional factors for the oriented differentiation of T-helper cells, the RVS glycoprotein (50 microg/mL) significantly suppressed the GATA-3, whereas it enhanced T-bet. Also, the RVS glycoprotein (100 microg/mL) significantly attenuated Th2-related cytokines (IL-4 and -10). Taken together, the results obtained from this study suggest that the RVS glycoprotein may help in preventing allergy-related immune dysfunction, such as that produced by BPA.

Expression of TNF-alpha and IL-6 in HMC-1 cells treated with bisphenol A is attenuated by plant-originating glycoprotein (75 kDa) by blocking p38 MAPK

Bisphenol A (BPA) is known as an estrogen-mimic environmental hormone which has the ability to indirectly stimulate the production of allergic inflammation-related cytokines. Cudrania tricuspidata Bureau (CTB) has been used in Korean folk medicine for a long time. In order to determine the inhibitory effect of a glycoprotein (CTB glycoprotein, 75 kDa) isolated from CTB fruits on the activities of allergic inflammation-related cytokines (TNF-alpha and IL-6) caused by BPA, we evaluated the activities of protein kinase C (PKC), p38 mitogen-activated protein kinase (p38 MAPK), nuclear factor (NF)-kappaB, and inflammation-related cytokine (TNF-alpha and IL-6) in the BPA-induced HMC-1 cells using immunoblot analysis and RT-PCR. The results obtained from this study revealed that CTB glycoprotein (100 microg/ml) inhibits the translocation of PKC from cytosol to the membrane, the phosphorylation of p38 MAPK, the activation of NF-kappaB, and the expression levels of TNF-alpha and IL-6. Taken together, the results in this study suggest that CTB glycoprotein inhibits the expression of allergic inflammation-related cytokines (TNF-alpha and IL-6) by blocking NF-kappaB and p38 kinase in BPA-induced HMC-1 cells.

Inferior alveolar nerve paresthesia after overfilling of endodontic sealer into the mandibular canal

The present study describes a case of endodontic sealer (AH Plus) penetration within and along the mandibular canal from the periapical zone of a lower second molar after endodontic treatment. The clinical manifestations comprised anesthesia of the left side of the lower lip, paresthesia and anesthesia of the gums in the third quadrant, and paresthesia and anesthesia of the left mental nerve, appearing immediately after endodontic treatment. The paresthesia and anesthesia of the lip and gums were seen to decrease, but the mental nerve paresthesia and anesthesia persisted after 3.5 years. This case illustrates the need to expend great care with all endodontic techniques when performing nonsurgical root canal therapy, especially when the root apices are in close proximity to vital anatomic structures such as the inferior alveolar canal.

Exposure to Bisphenol A prenatally or in adulthood promotes T(H)2 cytokine production associated with reduction of CD4CD25 regulatory T cells

BACKGROUND

Bisphenol A (BPA) is a widespread endocrine-disrupting chemical that can affect humans and animals.

OBJECTIVES

We investigated the effects of adult or prenatal exposure to BPA on T-helper (T(H))1/T(H)2 immune responses and the mechanisms underlying these effects.

METHODS

To evaluate the effects of exposure to BPA in adulthood, male Leishmania major-susceptible BALB/c and -resistant C57BL/6 mice were subcutaneously injected with 0.625, 1.25, 2.5, and 5 micromol BPA 1 week before being infected with L. major. To evaluate prenatal exposure, female mice were given BPA-containing drinking water at concentrations of 1, 10, and 100 nM for 2 weeks, then mated, and given BPA for another week. Male 10-week-old offspring were infected with L. major. Footpad swelling was assessed as a measure of the course of infection.

RESULTS

Mice exposed to BPA prenatally or in adulthood showed a dose-dependent increase in footpad swelling after being infected with L. major. Exposure to BPA in adulthood significantly promoted antigen-stimulated production of interleukin (IL)-4, IL-10, and IL-13 but not interferon-gamma (IFN-gamma). However, mice prenatally exposed to BPA showed increased production of not only IL-4 but also IFN-gamma. The percentages of CD4(+)CD25(+) cells were decreased in mice exposed to BPA either prenatally or in adulthood. Effects of prenatal BPA exposure were far more pronounced than effects of exposure in adulthood.

CONCLUSION

BPA promotes the development of T(H)2 cells in adulthood and both T(H)1 and T(H)2 cells in prenatal stages by reducing the number of regulatory T cells.

Accumulation of bisphenol A in hemodialysis patients

Bisphenol A [BPA, 2,2-bis(4-hydoxyphenyl)propane], an industrial chemical used in the production of polycarbonate, epoxide resin, and polyarylate, is considered to be an endocrine-disrupting chemical. BPA may be present in some hollow-fiber dialyzers used in hemodialysis. In this study, we tested the amounts of BPA eluted from various hollow fibers. Furthermore, we measured the BPA concentration in the sera of 22 renal disease predialysis patients, as well as 15 patients who were receiving hemodialysis, to see if there is BPA accumulation in these patients. The elution test of BPA showed that a much larger amount of BPA was eluted from polysulfone (PS), and polyester-polymeralloy hollow fibers. Among renal disease patients who had not undergone hemodialysis, the serum BPA concentration increased as the renal function deteriorated, showing a significant negative association. In a crossover test between PS and cellulose (Ce) dialyzers, the predialysis serum BPA concentration of PS dialyzer users decreased after changing to a Ce dialyzer, and the serum BPA increased again after switching back to PS dialyzers. In patients who were using PS dialyzers, the BPA level significantly increased after a dialysis session. However, in the Ce dialyzer users, the BPA level decreased. Since accumulation of BPA could affect the endocrine or metabolic system of the human body, it is important to perform further investigations on dialysis patients.

In vitro molecular mechanisms of bisphenol A action

Bisphenol A (BPA, 2,2-bis (4-hydroxyphenyl) propane; CAS# 80-05-7) is a chemical used primarily in the manufacture of polycarbonate plastic, epoxy resins and as a non-polymer additive to other plastics. Recent evidence has demonstrated that human and wildlife populations are exposed to levels of BPA which cause adverse reproductive and developmental effects in a number of different wildlife species and laboratory animal models. However, there are major uncertainties surrounding the spectrum of BPA's mechanisms of action, the tissue-specific impacts of exposures, and the critical windows of susceptibility during which target tissues are sensitive to BPA exposures. As a foundation to address some of those uncertainties, this review was prepared by the "In vitro" expert sub-panel assembled during the "Bisphenol A: An Examination of the Relevance of Ecological, In vitro and Laboratory Animal Studies for Assessing Risks to Human Health" workshop held in Chapel Hill, NC, Nov 28-29, 2006. The specific charge of this expert panel was to review and assess the strength of the published literature pertaining to the mechanisms of BPA action. The resulting document is a detailed review of published studies that have focused on the mechanistic basis of BPA action in diverse experimental models and an assessment of the strength of the evidence regarding the published BPA research.

Altered allergic cytokine and antibody response in mice treated with Bisphenol A

The objective of this study was to elucidate if Bisphenol A (BPA) administration modulates T helper (Th) cell component of immune responses in a mouse challenged with ovalbumin (OVA), a major food antigen. BALB/c mice, (6 weeks old, female) were orally given either OVA (OVA-fed) or water (Water-fed), immunized intraperitoneally with OVA and injected with either BPA in corn oil or the vehicle alone. After subsequent 2nd immunization, serum titers of total IgE, OVA-specific IgE, IgG, IgG1 IgG2a and ability of their splenocytes for production of interferon (IFN) -gamma, interleukin (IL) -4 and IL-12 were examined by ELISA. Lymphocyte proliferation assay against concanavalin A (Con A) or OVA was also performed for 3H-Thymidine incorporation. In Water-fed groups, treatment with BPA resulted in lower titers of total IgE (P<0.01) and higher levels IgG2a (P<0.05) followed by a higher IFN-gamma (P<0.05) and IL-12 (P<0.05) with an intact IL-4. When OVA-fed groups were examined, the compound did not change production of total and OVA-specific IgE and -IgG2a but resulted in lower production of IFN-gamma (P<0.05). Also, BPA resulted in impaired lymphocyte proliferation to Con A in Water-fed groups (P<0.05) but not in tolerated animals. The findings indicate that BPA results in augmentation of Th1 immune responses but no significant effect on an established tolerance to OVA.

Prenatal exposure to bisphenol A up-regulates immune responses, including T helper 1 and T helper 2 responses, in mice

The effect of prenatal exposure to bisphenol A (BPA) on the immune system in mice was investigated. Virgin female mice were fed varying doses of BPA, on a daily basis, over a period of 18 days commencing on the day of pairing with stud males (day 0). On day 77, their male offspring of 8 weeks were immunized with hen egg lysozyme (HEL). Three weeks later, anti-HEL immunoglobulin G (IgG) in sera, and proliferative responses of spleen cells to the antigen, were measured. Anti-HEL IgG2a and interferon-gamma (IFN-gamma), secreted from splenic lymphocytes, were measured as indicators of T helper 1 (Th1) immune responses, while anti-HEL IgG1 and interleukin-4 (IL-4) were measured as indicators of Th2 responses. The results showed that fetal exposure to BPA was followed by significant increases in anti-HEL IgG as well as antigen-specific cell proliferation. Both Th1 responses (including anti-HEL IgG2a and IFN-gamma production) and Th2 responses (including anti-HEL IgG1 and IL-4 production) were augmented by prenatal exposure to BPA, although the augmentation of Th1 responses appeared to be greater than that of Th2 responses. Two-colour flow cytometric analysis showed that mice exposed prenatally to BPA had 29% and 100% more splenic CD3(+) CD4(+) and CD3(+) CD8(+) cells, respectively, than control animals. Similar results were obtained from females whose mothers had consumed BPA during pregnancy. These results suggest that prenatal exposure to BPA may result in the up-regulation of immune responses, especially Th1 responses, in adulthood.

Effects of bisphenol A on antigen-specific antibody production, proliferative responses of lymphoid cells, and TH1 and TH2 immune responses in mice

1. We investigated the effect of bisphenol A (BPA), which binds estrogen receptors, on immune responses including production of antigen-specific antibodies, proliferative responses of lymphoid cells, and Th1 and Th2 responses. 2. For this investigation, mice were p.o. given varying doses including 3, 30, 300, and 3000 micro g kg(-1) of BPA immediately after immunization with hen egg lysozyme (HEL) (day 0) and then daily by day 20. On day 21, anti-HEL IgG antibodies in sera and proliferative responses of spleen cells to the antigen were measured. Anti-HEL IgG2a antibodies and IFN-gamma secreted from splenic lymphocytes were also measured as indicators of Th1 immune responses, while anti-HEL IgG1 antibodies and IL-4, as those of Th2 responses. 3. The results showed that treatment with 3000 micro g kg(-1) of BPA was followed by a significant increase in anti-HEL IgG as well as the antigen-specific cell proliferation. Anti-HEL IgG2a production and IFN-gamma secretion were significantly enhanced in mice treated with 300 and 30 micro g kg(-1) of BPA, respectively, while anti-HEL IgG1 production and IL-4 secretion were augmented in animals given 3000 and 300 micro g kg(-1) of the chemical, respectively. 4. Augmentation of these immune responses was also observed in mice exposed to 0.3-30 micro g kg(-1) of estradiol, although Th1 responses appeared to be more sensitive to the sex hormone than Th2 responses. 5. These results suggest that BPA may play a role in augmenting immune responses, especially Th1 responses.

The effect of AH 26 and AH Plus on MCF-7 breast cancer cell proliferation in vitro

AIM

The purpose of this study was to determine whether AH 26 and AH Plus have in vitro oestrogenic effects.

METHODOLOGY

MCF-7 breast cancer cells were trypsinized and plated in 24-well plates at initial concentrations of 10,000 cells per well in 5% FBS in DME. Cells were allowed to attach for 24 h; then the seeding medium was replaced with 10% CDHuS-supplemented phenol red-free DME. Different concentrations of the test compound were added to sample wells (AH 26 and AH Plus at 1/100 to 1/1,000,000 dilutions), 10 pM estradiol-17beta to positive controL and no sub-stance to negative control (hormone-free control cells). The assay was stopped after 144 h.

RESULTS

AH 26-powder induced MCF-7 cell proliferation in a dose-dependent manner. The cell yield obtained with AH 26-powder at 1/100 dilution sample was 2.5-fold greater than in control cultures. The sam-ple prepared with mixed AH 26 paste/powder 1:1 also induced MCF-7 cell proliferation, but showed less potency than AH 26-powder alone. The cell yield obtained with AH 26 paste/powder at 1/100 dilution sample was 1.9-fold greater than in control cultures. AH Plus did not show in vitro oestrogenic effect.

CONCLUSIONS

AH 26 showed in vitro oestrogenic effect, but not AH Plus. The endodontist must consider the possible oestrogenic effect of AH 26, as well as the cytotoxic effects of root filling materials, and avoid the leakage of sealer through the apex during root canal treatment.

Validation of HPLC and GC-MS systems for bisphenol-A leached from hemodialyzers on the basis of FUMI theory

This paper proposes a method for the validation of chromatography systems in which many experiments to estimate SD or RSD are difficult or impossible to carry out because of time, cost, etc. HPLC systems with UV-Vis and fluorescence detectors and GC-MS system for bisphenol-A leached from hemodialyzers are taken as an example. Examined as validation characteristics are not only the ordinary quantities (precision, accuracy, range, limit of detection (LOD), limit of quantitation (LOQ), specificity and linearity) but also precision plots (measurement RSD vs. concentration), 95% confidence intervals of calibration lines and LOD signals over baselines. The precision plots, calibration confidence intervals and LOD signals are shown to be advantageous to validate and compare the analytical performance of the systems. The LOD, LOQ, precision plots and 95% confidence intervals of calibration lines are all derived from the SD of measurements and the reliability of these quantities and plots depends totally on the reliability of the SD estimates. This paper uses a probability theory, called the FUMI theory, to estimate as exact a measurement SD as possible without the replication. The precision of the HPLC and GC-MS systems is shown to coincide with the repeatability obtained by the repetition of measurements.

Elution of bisphenol-A from hemodialyzers consisting of polycarbonate and polysulfone resins

This study deals with bisphenol-A (BPA) analysis of the BPA-derived polymer pellets, polycarbonate (PC) and polysulfone (PS), and in the hemodialyzer casings made of PC, and the leaching of BPA from commercially available hemodialyzers into water and bovine serum, using HPLC, GC-MS, and LC-MS analyses, and NMR spectroscopy. Total contents of BPA in polymer pellets of each resin were 4.0 and 7.2 microg/g (PC) and 34.5 microg/g (PS). Amounts of BPA released from hemodialyzer PC casings lacking PS hollow-fiber were 11.7 and 13.7 ng/casing by water extraction, and 296 and 345 ng/casing by methanol extraction. On the other hand, BPA of 3.78 to 141.8 ng/module was recovered using water circulation of hemodialyzers, and 140.7 to 2,090 ng/module was detected when bovine serum was used as a circulation solvent. The elution profiles using various concentrations of ethanol/water mixtures indicated that a 17.2% (v/v) ethanol solution rather than bovine serum can be used as an extraction solvent, where a similar amount of BPA as with bovine serum circulation was eluted from the hemodialyzer. Thus, this solvent may be useful for evaluating BPA elution from hemodialyers under similar conditions to medical use.

The immune system as a potential target for environmental estrogens (endocrine disrupters): a new emerging field

It is now well known that natural (17beta-estradiol) and synthetic (e.g. diethylstilbestrol) estrogens not only affect the reproductive system, but also markedly influence the immune system. Recently, a new class of estrogens that is abundant in the environment (in industrial chemicals, pesticides, and surfactants) has been recognized. Some of these estrogenic chemicals (which are a large subgroup of endocrine disrupters) have also been shown to influence the immune system. This review assimilates growing evidence in wildlife, laboratory animals and to a limited extent in humans, which suggests that environmental chemicals may also affect the immune system. Further studies are needed to ascertain the immunological consequences of exposure to environmental estrogens, especially in humans. At the present time, it is not known whether the human immune system responds to a low dose of environmental estrogens or if environmental estrogens influence certain subsets of human populations, rather than the general population. Conceivably, an alteration of the immune system by environmental estrogens could affect the individuals' ability to mount well-regulated immune responses to microbial and vaccine antigens, allergens, self and tumor antigens. Possible changes in the immune system must be investigated routinely in toxicity studies. A comprehensive mechanistic understanding of potential immunomodulatory chemicals is needed. In this regard, relevant laboratory animals may be especially useful in identifying susceptible periods of life, whether both genders are equally affected, in analysis of changes in target lymphoid organs, and to determine the immunological effects of mixtures of chemicals.