Extramural papers of the month
By Nancy Lamontagne
- Naphthalene exposure in children
- Inhalation of nanoparticles from cosmetics
- Transgenerational effects from BPA exposure
- Prenatal butylbenzyl phthalate and eczema
Naphthalene exposure in children
NIEHS grantees report that children exposed to high levels of naphthalene have a greater risk of chromosomal abnormalities, which have been associated with increased cancer risk in adults. Naphthalene is a polycyclic aromatic hydrocarbon found in automotive exhaust, tobacco smoke, and household mothball fumes.
The researchers followed 113 5-year-olds living in New York City and assessed the children's exposure to naphthalene, by measuring its metabolites, 1- and 2-naphthol, in urine. They also measured chromosomal abnormalities in the children's white blood cells.
The researchers found chromosomal abnormalities in 30 children, of which 11 had a type of abnormality known as a translocation. With every doubling of 1- and 2-naphthol levels, translocations were 1.55 and 1.92 times more likely, respectively. The researchers say that translocations can remain years after exposure, even though the body repairs some chromosomal damage. The researchers are now following some of the children through fourth grade, to better understand the long-term effects of naphthalene exposure.
Citation: Orjuela MA, Liu X, Miller RL, Warburton D, Tang D, Jobanputra V, Hoepner L, Suen IH, Diaz-Carreño S, Li Z, Sjodin A, Perera F. 2012. Urinary napthol metabolites and chromosomal aberrations in 5-year-old children. Cancer Epidemiol Biomarkers Prev 21(7):1191-1202.
Inhalation of nanoparticles from cosmetics
Nanoparticles from cosmetic powders can be inhaled and deposited in the upper airways, according to a new study from NIEHS-funded researchers. Although studies have looked at the toxicology of pure nanomaterials, very few have examined exposure during actual use of products containing nanomaterials.
The researchers studied six cosmetic powders, three of which were identified by the manufacturer as containing nanoparticles. Analysis, with transmission electron microscopy and laser diffraction spectroscopy, revealed that five of the six products contained nanoparticles. The investigators simulated exposure to the powders by applying them to a mannequin’s face while sampling airborne particles through ports in the mannequin’s nostrils.
The study results showed that someone using these cosmetic powders would be exposed to nanomaterials that were mostly clustered into agglomerates, or attached to larger particles. In this form, the nanomaterials would deposit in the upper airways, rather than the alveolar region of the lung, as would be expected from the size of the primary nanoparticles. Upper airway deposition could lead to different health effects than those found in nanoparticle toxicology studies for the alveolar region.
Citation: Nazarenko Y, Zhen H, Han T, Lioy PJ, Mainelis G. 2012. Potential for inhalation exposure to engineered nanoparticles from nanotechnology-based cosmetic powders. Environ Health Perspect 120(6):885-892.
Transgenerational effects from BPA exposure
An NIEHS grantee and her colleagues report that mice exposed to low doses of bisphenol A (BPA) while in the womb had immediate, as well as long-lasting, changes in the brain and social behaviors. Some of these changes persisted into the fourth generation. The researchers say that their findings have implications for complex neurological disease.
In the study, female mice received chow with or without BPA, before mating and throughout pregnancy. The levels of BPA present in the blood plasma of the female mice that received BPA were in a range similar to those measured in humans who were exposed to BPA.
The first generation offspring, which were exposed to BPA in the womb, displayed fewer social interactions compared to control mice. The researchers also found that BPA had an effect on the levels of the mRNA levels of neuropeptides vasopressin and oxytocin, which are both involved in social behaviors. Decreases in vasopressin levels were observed all the way through the fourth generation offspring.
Citation: Wolstenholme JT, Edwards M, Shetty SR, Gatewood JD, Taylor JA, Rissman EF, Connelly JJ. 2012. Gestational exposure to bisphenol A produces transgenerational changes in behaviors and gene expression. Endocrinology 153(8):3828-3838.
Prenatal butylbenzyl phthalate and eczema
An NIEHS-funded study shows that prenatal exposure to butylbenzyl phthalate (BBzP) can increase a child's risk for developing eczema. BBzP is found in vinyl flooring, artificial leather, and other materials, which can slowly release it into indoor air.
The study included 407 nonsmoking African-American and Dominican women and their children living in New York City. A urine test during the third trimester of pregnancy assessed BBzP exposure.
The researchers found that onset of eczema by age 2 was 52 percent more likely in children whose mothers were exposed to higher concentrations of BBzP, compared to those whose mothers were exposed to lower concentrations. The African-American mothers were twice as likely as the Dominican-American mothers to report that their child was diagnosed with eczema. However, both groups showed a similar association between BBzP exposure and eczema. The researchers examined allergies as a possible mechanism, but found no evidence of a link between BBzP exposure and allergy.
Citation: Just AC, Whyatt RM, Perzanowski MS, Calafat AM, Perera FP, Goldstein IF, Chen Q, Rundle AG, and Miller RL. 2012. Prenatal exposure to butylbenzyl phthalate and early eczema in an urban cohort. Environ Health Perspect; doi:10.1289/ehp.1104544 [Online 26 June 2012].
(Nancy Lamontagne is a science writer with MDB, Inc., a contractor for the NIEHS Division of Extramural Research and Training, Superfund Research Program, and Worker Education and Training Program.)