Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Myrto Petreas is active.

Publication


Featured researches published by Myrto Petreas.


Science of The Total Environment | 1995

Biotransfer and bioaccumulation of dioxins and furans from soil : chickens as a model for foraging animals

Robert D. Stephens; Myrto Petreas; Douglas G. Hayward

Chickens were used as a model for foraging animals to examine the bioavailability of all 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/PCDFs) from soil. Three groups of chickens were exposed through their diet to soil contaminated with PCDD/PCDFs at less than 0.5 pg/g I-TEQ (control group), 42 pg/g I-TEQ (low exposure group), and 460 pg/g I-TEQs (high exposure group). Eggs, tissues, feces and feed were analysed throughout the exposure and depuration period. Daily intake was estimated at 2.5 ng/kg-day for the high and 0.3 ng/kg-day for the low exposure groups. Bioavailability was chlorination-dependent ranging from 80% for tetrachlorinated to less than 10% for octachlorinated congeners. During exposure, tissue distribution was congener-dependent with 5-30% of the intake excreted in the eggs, 7-54% deposited in the adipose and less than 1% present in the liver. On a fat weight basis, the highest concentrations were observed in the liver, implying that mechanisms other than lipid solubility operate in that tissue. Bioconcentration factors and elimination half-lives were also congener- and tissue-dependent. Results from this study indicate that animals foraging on soil contaminated at low ppt PCDD/PCDF levels may bioaccumulate these compounds to unacceptable levels.


Environment International | 2009

Hydroxylated PCB metabolites (OH-PCBs) in archived serum from 1950-60s California mothers: a pilot study.

June-Soo Park; Myrto Petreas; Barbara A. Cohn; Piera M. Cirillo; Pam Factor-Litvak

We are studying participants selected from the Child Health and Development Studies (CHDS), a longitudinal birth cohort of over 20,000 California pregnancies between 1959 and 1967, for associations between maternal body burden of organochlorine contaminants and thyroid function. We designed a pilot study using 30 samples selected among samples with high and low PCB concentrations to evaluate the feasibility of measuring OH-PCBs in the larger study population. GC-ECD and GC-NCI/MS were used to determine PCBs and OH-PCBs as methyl derivatives, respectively. Maternal serum levels of Sigma11PCBs and Sigma8OH-PCB metabolites varied from 0.74 to 7.99 ng/mL wet wt. with a median of 3.05 ng/mL, and from 0.12 to 0.98 ng/mL wet wt. with a median of 0.39 ng/mL, respectively. Average concentrations of Sigma8OH-PCB metabolites in the high PCB group were significantly higher than those in the low PCB group (p < 0.05). The levels of OH-PCB metabolites were dependent on PCB levels (r = 0.58, p < 0.05) but approximately an order of magnitude lower (p < 0.05). The average ratio of Sigma8OH-PCBs to Sigma11PCBs was 0.14 +/- 0.08. The primary metabolite was 4-OH-CB187 followed by 4-OH-CB107. Both of these metabolites interfere with the thyroid system in in vitro, animal, and human studies. OH-PCBs were detectable in all archived sera analyzed, supporting the feasibility to measure OH-PCB metabolites in the entire cohort.


Marine Environmental Research | 2009

Polychlorinated biphenyls (PCBs) and their hydroxylated metabolites (OH-PCBs) in livers of harbor seals (Phoca vitulina) from San Francisco Bay, California and Gulf of Maine.

June-Soo Park; Olga Kalantzi; Dianne Kopec; Myrto Petreas

Bioaccumulation of endocrine disruptors in marine mammals positioned at the top of the food chain is of toxicological concern. Livers from four pups and ten adult harbor seals (Phoca vitulina) stranded in San Francisco Bay (SFB) and the Gulf of Maine (GOM) were analyzed for polychlorinated biphenyls (PCBs) and their hydroxylated metabolites (OH-PCBs). We used GC-ECD and GC-NCI/MS to investigate the presence of 28 PCBs and 8 OH-PCB metabolites, respectively. Sigma(28)PCB concentrations (di- to octa-CBs) ranged from 1.81 to 35.9 microg/g lipid with a median of 6.53 for the seal pups and 2.31 to 249 microg/g lipid with a median of 28.9 for the adult seals. Sigma(8)OH-PCB concentrations (penta- to hepta-OH-PCBs) ranged from 0.02 to 0.69 microg/g lipid with a median of 0.04 for the adult seals, i.e., at much lower concentrations than those for PCBs. Ratios of OH-PCBs to PCBs (0.24% on average) were comparable to those in beluga whale, but were lower than ratios in human livers. The OH-PCB profiles were slightly different between SFB and GOM seal livers, although similar PCB congener patterns were observed. Generally, 4-OH-CB107 was found predominantly in seal livers and was the only OH-PCB detectable in most of seal pup livers. This study provides information on OH-PCBs in seals, adding to the scarce exposure data for these chemicals.


Environmental Health | 2012

Prenatal polychlorinated biphenyl exposure is associated with decreased gestational length but not birth weight: archived samples from the Child Health and Development Studies pregnancy cohort.

Katrina Kezios; Xinhua Liu; Piera M Cirillio; Olga Kalantzi; Yunzhu Wang; Myrto Petreas; June-Soo Park; Gary Bradwin; Barbara A. Cohn; Pam Factor-Litvak

BackgroundPolychlorinated biphenyls (PCBs), known endocrine disruptors, were banned in 1979 but persist in the environment. Previous studies are inconsistent regarding prenatal exposure to PCBs and pregnancy outcomes. We investigated associations between prenatal exposure to PCBs and gestational length and birth weight.MethodsIn a sample of 600 infants (born between 1960 and 1963) randomly selected from Child Health and Development Studies participants followed through adolescence we measured 11 PCB congeners in maternal post partum sera (within three days of delivery). Length of gestation was computed from the reported first day of the last menstrual period (LMP) and delivery date. Linear regression was used to estimate associations between PCB exposure and gestational age and birth weight, adjusting for potential confounders. PCBs were grouped according to hypothesized biological action (1b (sum of weak phenobarbital inducers), 2b (sum of limited dioxin activity), and 3 (sum of CYP1A and CYP2b inducers)) or degree of ortho- substitution (mono, di, tri). Secondary analyses examined associations between total PCB exposure and exposure to individual congeners.ResultsEach unit increase in mono-ortho substituted PCBs was associated with a 0.30 week decrease (95% confidence interval (CI) -0.59, -0.016), corresponding to a 2.1 (95% CI −4.13, -0.11) day decrease in length of gestation. Similar associations were estimated for di-ortho substituted PCBs, (1.4 day decrease; (95% CI −2.9, 0.1)) and group 3 PCBs (0.84 day decrease; (95% CI −1.8, 0.11). We found similar associations in congener specific analyses and for the sum of congeners.ConclusionsOur study provides new evidence that PCB exposure shortens length of gestation in humans. This may have public health implications for population exposures.


Environmental Toxicology and Chemistry | 2011

Legacy and contemporary persistent organic pollutants in North Pacific albatross

Suhash Harwani; Robert W. Henry; Alexandra Rhee; Michelle A. Kappes; Donald A. Croll; Myrto Petreas; June-Soo Park

Here we report the first measurements of polybrominated diphenyl ethers (PBDE 47, 99, and 153) alongside 11 organochlorine pesticides (OCPs) and 28 polychlorinated biphenyls (PCBs) in the plasma of albatross from breeding colonies distributed across a large spatial east-west gradient in the North Pacific Ocean. North Pacific albatross are wide-ranging, top-level consumers that forage in pelagic regions of the North Pacific Ocean, making them an ideal sentinel species for detection and distribution of marine contaminants. Our work on contaminant burdens in albatross tissue provides information on transport of persistent organic pollutants (POPs) to the remote North Pacific and serves as a proxy for regional environmental quality. We sampled black-footed (Phoebastria nigripes; n = 20) and Laysan albatross (P. immutabilis; n = 19) nesting on Tern Island, Hawaii, USA, and Laysan albatross (n = 16) nesting on Guadalupe Island, Mexico. Our results indicate that North Pacific albatross are highly exposed to both PCBs and OCPs, with levels ranging from 8.8 to 86.9 ng/ml wet weight and 7.4 to 162.3 ng/ml wet weight, respectively. A strong significant gradient exists between Laysan albatross breeding in the Eastern Pacific, having approximately 1.5-fold and 2.5-fold higher levels for PCBs and OCPs, respectively, compared to those from the Central Pacific. Interspecies levels of contaminants within the same breeding site also showed high variation, with Tern black-footed albatross having approximately threefold higher levels of both PCBs and OCPs than Tern Laysan albatross. Surprisingly, while PBDEs are known to travel long distances and bioaccumulate in wildlife of high trophic status, we detected these three PBDE congeners only at trace levels ranging from not detectable (ND) to 0.74 ng/ml wet weight in these albatross.


Reproductive Toxicology | 2017

Hydroxylated polychlorinated biphenyl metabolites (OH-PCBs), maternal smoking and size at birth

Katrina Kezios; Yiwei Gu; Xinhua Liu; Piera M. Cirillo; Darcy Tarrant; Myrto Petreas; Jun-Soo Park; Barbara A. Cohn; Pam Factor-Litvak

In a sample of 442 births from the Child Health and Development Studies cohort, we examined associations between maternal prenatal exposure to hydroxylated polychlorinated biphenyl metabolites (OH-PCBs) and pregnancy outcomes, and whether associations were mediated by maternal thyroid hormone levels and/or modified by maternal smoking. Compared to nonsmokers, smokers had twice the mean concentration of 4-OH-CB107 (p<0.001) and lower levels of its parent compound, PCB118 (p=0.001). Among mothers who smoked, the birth weight of newborns with maternal concentrations of 4-OH-CB107 in the upper quartile was 316g lighter (95% confidence interval (CI) 566, 65) compared to those with maternal concentrations in the lowest quartile, after control for PCB118 and other potential confounders. This association was not observed for non-smoking mothers and was not mediated by maternal thyroid hormone levels. Maternal prenatal 4-OH-CB107 levels appear to be influenced by maternal smoking and contribute to lower birth weight among smokers.


American Journal of Epidemiology | 2005

Association of DDT and DDE with Birth Weight and Length of Gestation in the Child Health and Development Studies, 1959–1967

Lili Farhang; June M. Weintraub; Myrto Petreas; Brenda Eskenazi; Rajiv Bhatia


Journal of Chromatography B | 2004

Evaluation of four capillary columns for the analysis of organochlorine pesticides, polychlorinated biphenyls, and polybrominated diphenyl ethers in human serum for epidemiologic studies

Evan W. Rogers; Myrto Petreas; June-Soo Park; Guomao Zhao; M. Judith Charles


Reproductive Toxicology | 2013

Dichlorodiphenyltrichloroethane (DDT), DDT metabolites and pregnancy outcomes

Katrina Kezios; Xinhua Liu; Piera M. Cirillo; Barbara A. Cohn; Olga I. Kalantzi; Yunzhu Wang; Myrto Petreas; June-Soo Park; Pam Factor-Litvak


Environment International | 2011

Assaying Organochlorines in archived serum for a large, long-term cohort: Implications of combining assay results from multiple laboratories over time

Robert I. Sholtz; Katherine R. McLaughlin; Piera M. Cirillo; Myrto Petreas; June-Soo Park; Mary S. Wolff; Pam Factor-Litvak; Brenda Eskenazi; Nickilou Y. Krigbaum; Barbara A. Cohn

Collaboration


Dive into the Myrto Petreas's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Olga Kalantzi

California Environmental Protection Agency

View shared research outputs
Top Co-Authors

Avatar

Yunzhu Wang

California Department of Toxic Substances Control

View shared research outputs
Top Co-Authors

Avatar

Alexandra Rhee

California Environmental Protection Agency

View shared research outputs
Top Co-Authors

Avatar

Darcy Tarrant

California Environmental Protection Agency

View shared research outputs
Researchain Logo
Decentralizing Knowledge