The Global Fool

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Early Menopause: Links to Ubiquitous Endocrine-Disrupting Chemicals
Feb23

Early Menopause: Links to Ubiquitous Endocrine-Disrupting Chemicals

By Roberta Attanasio There are as many endocrine-disrupting chemicals (also called endocrine disruptors) as there are deleterious health effects caused by them. These chemicals mimic the body’s hormones and confuse our physiological systems — we respond to them with a series of inappropriate changes that, depending on the specific endocrine disruptor, lead to the development of obesity, cancer, malformation of sex organs, and more. They are pervasive in the environment — they’re found in the soil, air and water throughout the world — and many persist for long periods of time. Thus, it’s not surprising that, in 2013, the impact of endocrine disruptors on human health was defined as a “global threat” by a group of experts convened by the United Nations Environment Programme and the World Health Organization.   Phthalates are some of the most studied endocrine disruptors. They’re used to make plastic more flexible and cosmetics smoother. Phthalate use in children’s toys was banned in 2008. However, results from a recent study show that high amounts of certain phthalates are present in some meats, cooking oils and dairy products, thus contributing to children exposure despite the ban. In her article “A threat to male fertility“, Deborah Blum writes: “A growing body of work over the last two decades suggests that phthalates can rewire the male reproductive system, interfering with the operation of androgenic hormones, such as testosterone, that play key roles in male development. That mechanism, some experts believe, explains findings that link phthalate exposure to changes in everything from testicular development to sperm quality.” In addition, according to results from a new study, two phthalates belong to a group of 15 chemicals that are significantly associated with early menopause and may have detrimental effects on ovarian function. Earlier menopause and decline in ovarian function may adversely affect fertility and lead to earlier development of heart disease and osteoporosis. The other chemicals are nine polychlorinated biphenyls, three pesticides, and a furan. Women that have high levels of these chemicals in their bodies experience menopause two to four years earlier than women with lower levels of these chemicals. For the study, the researchers analyzed data collected from 1999-2008 as part of the National Health and Nutrition Examination Survey, conducted by the U.S. Centers for Disease Control and Prevention. The survey incrporated data from 31,575 people, including 1,442 menopausal women who had been tested for presence of endocrine-disrupting chemicals in their blood and urines. It was designed so that the women who had undergone chemical testing would represent a population of almost 9 million menopausal women. The strongest association with early menopause was found for mono-(2-ethyl-5-hydroxyhexyl) phthalate and mono-(2-ethyl-5-oxohexyl) phthalate,...

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E-Cigarettes and Vaping May Cause Lung Damage and Impaired Immune Responses
Feb14

E-Cigarettes and Vaping May Cause Lung Damage and Impaired Immune Responses

By Roberta Attanasio A few months ago, Oxford Dictionaries announced “vape” as its international Word of the Year 2014 – language research conducted by their editors revealed that its use in 2014 had more than doubled compared to 2013 (and increased by 30-fold since 2012), mostly because of the rapidly growing popularity of electronic cigarettes and the expanding debate over their safety. Although e-cigarettes are portrayed as devices that can help adult smokers quit while providing a safe alternative to tobacco smoking, mounting evidence shows that these devices may cause considerable harm. Indeed, about two weeks ago, California health officials said that e-cigarettes represent a rising public-health risk that threaten to unravel progress made on tobacco by “re-normalizing smoking behavior” and luring a new generation into nicotine addiction. Electronic cigarettes, or e-cigarettes, are tobacco-free and vaporize liquid (also called e-liquid or e-juice) that contains nicotine, producing “faux” smoke or vapor. Because they don’t burn anything, e-cigarettes don’t release any smoke – therefore, users don’t “smoke”, they “vape.” In addition to nicotine, the e-juice typically contains vegetable glycerin, propylene glycol, and flavorings. There are several types of e-juices, each containing different flavorings – these flavorings make “vaping” especially appealing to young smokers who would not normally try tobacco. While nicotine addiction caused by vaping in young smokers is clearly a major public health issue, there are also public health concerns associated with toxic substances released by e-cigarette vapors. Indeed, e-cigarettes may likely become a toxic replacement for tobacco products. Results from a recent study (published in the scientific journal PLOSone) show that emissions from e-cigarettes damage lung cells. The damage is mostly caused by inflammatory responses and oxidative stress, which are known to represent key events in the development of chronic airway diseases. Some flavored e-juices – particularly those containing cinnamon – are more toxic than others. Irfan Rahman, lead author of the study, said in a press release: “Several leading medical groups, organizations, and scientists are concerned about the lack of restrictions and regulations for e-cigarettes. Our research affirms that e-cigarettes may pose significant health risks and should be investigated further. It seems that every day a new e-cigarette product is launched without knowing the harmful health effects of these products.” Results from an additional study recently published in the same journal confirm that vaping may cause potential deleterious health effects. Using a mouse model, the researchers showed that e-cigarettes compromise the immune system in the lungs and generate some of the same potentially dangerous chemicals found in traditional nicotine cigarettes. Thomas Sussan, lead author of this study, said in a press release: “E-cigarette vapor alone produced mild effects...

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Prenatal Exposure to Pollutants: Influence on the Immune Response
Nov30

Prenatal Exposure to Pollutants: Influence on the Immune Response

By Roberta Attanasio The development of the immune system during fetal and neonatal life is negatively influenced by exposure to toxic chemicals, resulting in compromised immune function later in life. An example is fetal exposure to arsenic, which has deleterious effects on the immune response to influenza virus infection in adulthood. Now, results from a new study provide additional evidence for the role that exposure to toxic chemicals early in life plays in shaping the immune response to the influenza virus.   The study (by researchers at the University of Rochester) focused on a mouse model and the chemical 2,3,7,8-tetrachlordibenzo-p-dioxin, or TCDD for short. TCDD, a known carcinogen, is a persistent environmental contaminant usually present in a complex mixture of dioxin-like compounds. It’s a by-product of industrial processes such as pesticide and metal production, waste incineration and wood combustion, and acts via the aryl hydrocarbon receptor, which is present in all cells. The aryl hydrocarbon receptor is a ligand-activated transcription factor that controls the expression of a diverse set of genes.  The researchers designed their mouse study to expand previous epidemiological findings from human studies. These findings showed correlation between maternal exposure to pollutants that bind the aryl hydrocarbon receptor and the decreased ability of the offspring to combat respiratory infections and produce antibodies. In other words, the epidemiological findings indicated that mothers exposed to these pollutants while pregnant may give birth to babies with impaired immune function.  An effective immune response requires the coordinated action of several cell types. CD4+ T cells, one of these cell types, exist in different subsets. It has been known for several years that, by binding the aryl hydrocarbon receptor, some chemicals influence the different subsets of CD4+ T cells, thus resulting in the observed impaired immune function. However, it was not known whether or not prenatal exposure to these chemicals could cause changes in the different CD4+ T cell subsets. The researchers that carried out the new study wanted to know whether or not fetal exposure to an aryl hydrocarbon receptor ligand (in this case TCDD) directly alters CD4+ T cell differentiation and function later in life. Thus, they exposed pregnant female mice to TCDD and then infected the adult offspring with the influenza virus. The results show that the offspring of the exposed pregnant mothers had a reduced frequency of different subsets of CD4+ T cells when compared with mice born to untreated mothers. In addition, exposed mice produced considerable lower levels of a specific class of antibodies against the influenza virus than control mice.   Then, the researchers transferred CD4+ T cells from the exposed offspring into unexposed mice. They found that, following cell transfer, the unexposed mice responded to influenza virus...

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Nanoparticles and Sunscreen Products: Toxicity to Sea Life in Coastal Waters
Aug31

Nanoparticles and Sunscreen Products: Toxicity to Sea Life in Coastal Waters

By Roberta Attanasio The debate on the safety of titanium dioxide (TiO2) and zinc oxide (ZnO) nanoparticles contained in sunscreen products is still on. Some scientists have raised concerns about the negative impact that these tiny particles — generally between one and 100 nanometers (between one and 100 billionths of a meter) across — may have on human health. Due to their small size, nanoparticles might do harm to humans by seeping through the skin and into the bloodstream. A few months ago, despite the widespread safety concerns, Paul Wright (a toxicology expert at RMIT University) told The Guardian that sunscreen nanoparticles don’t get past the outermost dead layer of human skin cells. In contrast, Paul Westerhoff (a professor at Arizona State University’s School of Sustainable Engineering and the Built Environment) told The New York Times that the products have not been thoroughly studied and are minimally regulated — he concluded: “I’m just saying we need to figure out if we should worry.” We need to figure out if we should worry not only in terms of human health, but also in terms of toxicity to the environment. About a year ago, Antonio Tovar-Sánchez (Department of Global Change Research, Mediterranean Institute for Advanced Studies, Esporles, Balearic Island, Spain) and collaborators reported the potential effects of commercial sunscreens released in nearshore waters by beachgoers. The researchers sampled surface nearshore waters of three beaches around Majorca Island and demonstrated that sunscreen products are a significant source of organic and inorganic chemicals that reach the sea with potential ecological consequences on the coastal marine ecosystem, inhibiting the growth of some species of marine phytoplankton or adding essential micronutrients that may stimulate the growth of others. In a new study published July 28, 2014 (Sunscreens as a Source of Hydrogen Peroxide Production in Coastal Waters), Antonio Tovar-Sánchez and his collaborator David Sánchez-Quiles show that titanium dioxide and zinc oxide nanoparticles — when exposed to solar radiation —  produce significant amounts of hydrogen peroxide (H2O2), a strong oxidizing agent able to generates high levels of stress on phytoplankton, the microscopic organisms that feed marine animals, from small fish to shrimp to whales..  The researchers went to Majorca Island’s Palmira beach on the Mediterranean along with about 10,000 beachgoers, a small portion of the more than 200 million tourists that flock to Mediterranean shores every year. Based on lab tests, seawater sampling and tourism data, they concluded that titanium dioxide nanoparticles contained in sunscreen products are largely responsible for a dramatic summertime spike in hydrogen peroxide levels in coastal waters.  The researchers point out, in a press release, that other than staying indoors, slathering on sunscreen is currently the best way to protect the skin from the sun’s harmful rays. However, when sunbathers...

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Prenatal Exposure to Persistent Organic Pollutants: Influence on Masculine and Feminine Behavior in School-Age Children
Apr18

Prenatal Exposure to Persistent Organic Pollutants: Influence on Masculine and Feminine Behavior in School-Age Children

By Roberta Attanasio Persistent environmental pollutants – such as DDT, dioxins and polychlorinated biphenyls – are a major global health threat. These toxic chemicals resist degradation and persist in the environment for long periods of time. They can be transported by wind and water across international boundaries, and reach regions far from where they are produced or used. People are exposed to these chemicals mostly by eating contaminated fish, meat, and dairy products and, once exposed, may develop a variety of adverse health effects, including birth defects, dysfunctions of the immune and reproductive systems, damage to the central and peripheral nervous systems, and certain cancers. Now, results from a study (Behavioral Sexual Dimorphism in School-Age Children and Early Developmental Exposure to Dioxins and PCBs: A Follow-Up Study of the Duisburg Cohort) published on March 1, 2014 in the scientific journal Environmental Health Perspectives, show that school-age boys and girls exposed to low levels of persistent organic pollutants during fetal life exhibit behavioral changes related to sexual dimorphism – boys show more feminine behavior and girls show less feminine behavior. The study was carried out using the Duisburg cohort, which consisted of 232 healthy pregnant women living in Duisburg, Germany, from September 2000 through October 2002. Duisburg is located in an area that was an important agglomeration for heavy industries. The researchers collected blood samples at 28-43 weeks of gestation and then, after the babies were born, breast milk samples. For the study, all samples were analyzed for presence of dioxins and polychlorinated biphenyls, which are also known endocrine-disrupting chemicals. Once the children reached the age of 6-8 years, parents were asked to report their play behavior, which is known to show profound differences related to gender. For the study, the play behavior was characterized on the basis of “24 items grouped into three categories: preferred toys (e.g., guns, dolls), preferred activities (e.g., playing house, fighting), and behavioral characteristics (e.g., enjoys rough and tumble play, likes pretty things).” For each of these items, parents reported the perceived frequency of occurrence during the preceding month (never, hardly ever, sometimes, often, very often). The researchers found linear dose-response relationships between exposure and outcome – thus, they conclude that low levels of prenatal environmental exposure to dioxins and polychlorinated biphenyls modify behavioral sexual dimorphism in school-age children. Their article has been selected by the Children’s Environmental Health Network (CEHN) as one of the “Articles of the Month” (April 2014 issue). The summary presented by CEHN includes the discussion of the potential policy implications related to the new...

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