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Background: Perfluorinated compounds are ubiquitous pollutants; epidemiologic data suggest they may be associated with adverse health outcomes, including subfecundity. We examined subfecundity in relation to 2 perfluorinated compounds-perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA).Methods: This case-control analysis included 910 women enrolled in the Norwegian Mother and Child Cohort Study in 2003 and 2004. Around gestational week 17, women reported their time to pregnancy and provided blood samples. Cases consisted of 416 women with a time to pregnancy greater than 12 months, considered subfecund. Plasma concentrations of perfluorinated compounds were analyzed using liquid chromatography-mass spectrometry. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated for each pollutant quartile using logistic regression. Estimates were further stratified by parity.Results: The median plasma concentration of PFOS was 13.0 ng/mL (interquartile range [IQR] = 10.3-16.6 ng/mL) and of PFOA was 2.2 ng/mL (IQR = 1.7-3.0 ng/mL). The relative odds of subfecundity among parous women was 2.1 (95% CI = 1.2-3.8) for the highest PFOS quartile and 2.1 (1.0-4.0) for the highest PFOA quartile. Among nulliparous women, the respective relative odds were 0.7 (0.4-1.3) and 0.5 (0.2-1.2).Conclusion: Previous studies suggest that the body burden of perfluorinated compounds decreases during pregnancy and lactation through transfer to the fetus and to breast milk. Afterward, the body burden may increase again. Among parous women, increased body burden may be due to a long interpregnancy interval rather than the cause of a long time to pregnancy. Therefore, data from nulliparous women may be more informative regarding toxic effects of perfluorinated compounds. Our results among nulliparous women did not support an association with subfecundity. [ABSTRACT FROM AUTHOR]

Melatonin (MEL) is a widely used, over-the-counter sleep aid, and it has putative contraceptive, antioxidant, antiaging, and anticancer effects. The developmental toxicity potential for repeated oral doses of MEL had not previously been evaluated. In the present studies, time-mated, Sprague-Dawley-derived (CD®) rats were administered MEL or vehicle by gavage on gestation days (gd) 6-19. MEL-treated groups received 1-, 10-, 100-, 150-, or 200-mg/kg body weight/day in the screening study (15 rats/group), and 50, 100, or 200 mg/kg/day in the definitive study (25 rats/group). In both studies, maternal food/water consumption, body weight, and clinical signs were monitored at regular intervals throughout gestation. At termination (gd 20, both studies), maternal liver and gravid uterine weights, number of ovarian corpora lutea, conceptus survival, fetal sex, and fetal body weight were evaluated. Fetal morphological examination included external structures (both studies) as well as visceral and skeletal structures (definitive study). In the screening study, maternal serum levels of 17β-estradiol, progesterone, prolactin, and luteinizing hormone were determined by radioimmunoassay, and mammary tissue was fixed, stained, and evaluated for percent glandular area within the fat pad. No maternal morbidity/mortality was found in either study. In the screening study, aversion to treatment (100 mg/kg/ day) and reduced maternal weight gain (150 mg/kg/day) were noted, but reproductive/endocrine parameters and fetal development were not affected. In the definitive study, aversion to treatment was noted at 2,-50 mg/kg/day, and mild sedation, reduced maternal food intake, and reduced body weight gain were found during initial treatment with 200 mg/kg/day. MEL had no effect on prenatal survival, fetal body weight, or incidences of fetal malformations/variations. Thus, in the definitive study, the maternal toxicity NOAEL and LOAEL were 100 and 200 mg/kg/day, respectively, and the developmental toxicity NOAEL was 200 mg/kg/day. [ABSTRACT FROM PUBLISHER]

Toxicity studies were performed by exposing F344/N rats and B6C3F1 mice (10 animals per sex per species per group) to transient-free, linearly polarized 60 Hz magnetic fields for 8 weeks. Targeted magnetic fields strengths used were 0 gauss (G; sham control fields did not exceed 0.001 G), 0.02 G, 2 G, and 10 G. Exposure was whole-body and continuous for 18.5 hr per day, 7 days per week. An additional group of rats and mice was exposed intermittently (1 hr on/1 hr off) to 10 G fields for the same period of time. Endpoints evaluated included morbidity, mortality, gross pathology, histopathology, body/organ weights, clinical chemistry (rats only), and hematology (rats only). All mice and all male rats survived until the end of the study. One female rat (2-G exposure group) died during Week 7 of the study; the death was not attributed to magnetic field exposure. In both studies, the mean body weight gains of exposed animals were similar to those of the respective controls. There were no gross, histological, hematological, or biochemical lesions attributed to magnetic field exposure. Statistically significant increases in liver weight and liver to body weight ratio occurred in female rats of all exposure groups but only at the termination. These data suggest that, for the variables evaluated in these studies, an 8-week exposure to linear-polarized, transientfree 60 Hz magnetic fields at field intensities of up to 10 G is not associated with significant toxicity in F344/N rats and B6C3F1 mice. Furthermore, there was no toxicity observed in animals receiving intermittent (1 hr on/l hr off) exposures to 10-G fields. A 2-year study in F344/N rats and B6C3F1 mice is nearing completion of the in-life phase without overt toxicity in any exposed group. It is premature, however, to make any prediction concerning the possible influence of exposure to 60 Hz magnetic fields on cancer rates. [ABSTRACT FROM AUTHOR]

Background: Exposure to phenols, endocrine-disrupting chemicals used in personal care and consumer products, is widespread. Data on infant exposures are limited despite heightened sensitivity to endocrine disruption during this developmental period. We aimed to describe distributions and predictors of urinary phenol concentrations among U.S. infants ages 6-12 weeks., Methods: The Infant Feeding and Early Development (IFED) study is a prospective cohort study of healthy term infants enrolled during 2010-2013 in the Philadelphia region. We measured concentrations of seven phenols in 352 urine samples collected during the 6- or 8- and/or 12-week study visits from 199 infants. We used linear mixed models to estimate associations of maternal, sociodemographic, infant, and sample characteristics with natural-log transformed, creatinine-standardized phenol concentrations and present results as mean percent change from the reference level., Results: Median concentrations (μg/L) were 311 for methylparaben, 10.3 for propylparaben, 3.6 for benzophenone-3, 2.1 for triclosan, 1.0 for 2,5-dichlorophenol, 0.7 for BPA, and 0.3 for 2,4-dichlorophenol. Geometric mean methylparaben concentrations were approximately 10 times higher than published estimates for U.S. children ages 3-5 and 6-11 years, while propylparaben concentrations were 3-4 times higher. Infants of Black mothers had higher concentrations of BPA (83%), methylparaben (121%), propylparaben (218%), and 2,5-dichorophenol (287%) and lower concentrations of benzophenone-3 (-77%) and triclosan (-53%) than infants of White mothers. Triclosan concentrations were higher in breastfed infants (176%) and lower in infants whose mothers had a high school education or less (-62%). Phenol concentrations were generally higher in summer samples., Conclusions: Widespread exposure to select environmental phenols among this cohort of healthy U.S. infants, including much higher paraben concentrations compared to those reported for U.S. children, supports the importance of expanding population-based biomonitoring programs to infants and toddlers. Future investigation of exposure sources is warranted to identify opportunities to minimize exposures during these sensitive periods of development., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Co-author serves as an Associate Editor for this journal - K.K.F. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Published by Elsevier Inc.)

Sodium metavanadate (NaVO 3 ) is a pentavalent vanadium compound used in the metal industry and dietary supplements; human exposure occurs through inhalation of fumes and dust and ingestion of NaVO 3 -containing products. The objective of this study was to assess the potential immunotoxicity of NaVO 3 . Female B6C3F1/N mice were exposed to 0-500 ppm NaVO 3 in drinking water for 28 days and evaluated for effects on immune cell populations and innate, cellular-mediated, and humoral-mediated immunity. There was a decreasing trend in body weight (BW) and BW gain in NaVO 3 exposed mice, with a decrease (p ≤ 0.05) in BW gain at ≥250 ppm, relative to control. Conversely, increasing trends in spleen weights and an increase (p ≤ 0.05) in the spleen:BW ratio at ≥250 ppm NaVO 3 were observed. NaVO 3 exposure altered antibody production against sheep red blood cells (SRBC). Antibody forming cells (AFC)/10 6 spleen cells exhibited a decreasing trend, with a decrease (p ≤ 0.05) at 500 ppm NaVO 3 , concurrent with an increase in percent B cells. NaVO 3 had no effect on the serum anti-SRBC IgM antibody titers or anti-keyhole limpet hemocyanin antibody production. Exposure to NaVO 3 decreased the percentage of natural killer cells at all dose levels (p ≤ 0.05), with no effect on the lytic activity. NaVO 3 altered T-cell populations at 500 ppm but had no effect on T-cell proliferative responses or the lytic activity of cytotoxic T cells. Collectively, these data indicate that NaVO 3 exposure can adversely affect the immune system by inducing alterations in humoral-mediated immunity, specifically the AFC response, with no effect on cell-mediated or innate immunity., (Published 2023. This article is a U.S. Government work and is in the public domain in the USA.)

2-Methoxy-4-nitroaniline (MNA), an intermediate in the synthesis of azo dyes used in textiles and paints, is structurally similar to carcinogenic anilines. Human exposure occurs primarily in the occupational setting through handling of dye dust, and through use and disposal of MNA-containing products. MNA has been reported to induce contact hypersensitivity in a human, myocardial necrosis in rats, and bacterial mutagenicity. This study assessed the subacute toxicity, genotoxicity, contact hypersensitivity, and reproductive toxicity of MNA in rodents in an effort to more fully characterize its toxicological profile. B6C3F1/N mice were exposed to 0, 650, 1250, 2500, 5000, or 10,000 ppm MNA by dosed feed for 14-days to evaluate subacute toxicity and histopathological endpoints. In female mice, decreased body weight (13.5 %) and absolute kidney weight (14.8 %), compared to control, were observed at 10,000 ppm MNA; increased relative liver weight (10-12 %), compared to control, occurred at 5,000-10,000 ppm MNA. In male mice, absolute (15 %) and relative liver weights (9-13 %) were increased at 2,500-5,000 ppm and 1250-10,000 ppm MNA, compared to control, respectively. In both sexes of mice, minimal elevations of hemosiderin pigmentation (a breakdown product of erythrocytes), relative to control, were observed in the liver (10,000 ppm); minimal to moderate elevations of hemosiderin pigmentation (5,000-10,000 ppm) and minimal increases in hematopoietic cell proliferation occurred in the spleen (≥ 1250 ppm). In a reproductive toxicity study, timed-mated female Harlan Sprague Dawley rats were exposed to 0-10,000 ppm MNA by dosed feed from gestation day 6 through postnatal day (PND) 21. Decreases in mean litter weights were observed at 5000 ppm MNA, compared to control, beginning at PND1. To evaluate potential contact hypersensitivity, MNA (2.5-50 %, in dimethylformamide) was applied to the dorsa of both ears of female Balb/c mice once daily for three days. The increase observed in lymph node cell proliferation (10-50 % increase in thymidine uptake compared to control) did not reproducibly achieve the Sensitization Index (SI) 3 level, and there was no ear swelling evident following sensitization with 10-50 % MNA and challenge with 25 % MNA in the mouse ear swelling test. In bacterial mutagenicity assays, MNA (250-1000 μg/plate) induced significant increases, compared to control, in mutant colonies with and without metabolic activation enzymes in Salmonella typhimurium strains TA100 and TA98. These data indicate that MNA is genotoxic, and may induce erythrocyte damage and reactive phagocytosis by macrophages in the liver and spleen., (Published by Elsevier B.V.)

This session explored the effects of pollutants on One Health at the ecosystem level that included microbes, insects, fish, and humans. The concept of One Health seeks to synergize medical, veterinary, and other health science disciplines to more effectively advance human and animal health. Presentations explored the interactions of pesticides, pathogens, phytochemicals, and xenobiotic biotransformation in bee colony losses critical for food security (bees have been recently listed under the 2017 US Food and Drug Administration (FDA) veterinary feed directive); the role of pathology in identifying the effects of pollutants on fish as sentinels for human health; the effects in rats of per- and polyfluoroalkyl substances (PFAS) that can persist in the environment and contaminate drinking water; harmful algal blooms and toxin production leading to animal and human disease; and the processing of environmental carcinogens by intestinal microbiota.

We showed previously that in utero exposure to the cholesterol-lowering drug simvastatin (SMV) during sex differentiation lowers fetal lipids and testicular testosterone production (T Prod) in Hsd:SD rats. Here, the effects of SMV on fetal lipids and T Prod in Crl:CD(SD) rats were correlated with postnatal alterations in F1 males. The current study was conducted in two parts: 1) a prenatal assessment to confirm and further characterize the dose response relationship among previously reported alterations of SMV on fetal T Prod and the fetal lipid profile and 2) a postnatal assessment to determine the effects of SMV exposure during the periods of major organogenesis and/or sexual differentiation on F1 offspring growth and development. We hypothesized that SMV would have adverse effects on postnatal development and sexual differentiation as a consequence of the disruptions of fetal lipid levels and testicular T Prod since fetal cholesterol is essential for normal intrauterine growth and development and steroid synthesis. In the prenatal assessment, SMV was administered orally at 0, 15.6, 31.25, 62.5, 80, 90, 100, and 110 mg SMV/kg/d from GD 14-18, the period that cover the critical window of sex differentiation in the male rat fetus. T Prod was maximally reduced by ~40% at 62.5 mg/kg/d, and higher doses induced overt maternal and toxicity. In the postnatal assessment, SMV was administered at 0, 15.6, 31.25, and 62.5 mg/kg/d from GD 8-18 to determine if it altered postnatal development. We found that exposure during this time frame to 62.5 mg SMV/kg/d reduced pup viability by 92%, decreased neonatal anogenital distance, and altered testis histology and morphology in 17% of the F1 males. In another group, SMV was administered only during the masculinizing window (GD14-18) at 62.5 mg/kg/d to determine if male rat sexual differentiation and postnatal reproductive development were altered. SMV-exposed F1 males displayed female-like areolae/nipples, delayed puberty, and reduced seminal vesicle and levator ani-bulbocavernosus weights. Together, these results demonstrate that in utero exposure to SMV reduces offspring viability and permanently disrupts reproductive tract development in the male offspring. While the effects of high dose, short term in utero exposure to SMV in the adult male are likely androgen-dependent and consistent with the 40% reduction in T Prod in the fetal testes, long-term, lower dose administration induced some effects that were likely not mediated by decreased T Prod., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Cylindrospermopsin (CYN) is a toxin associated with numerous species of freshwater cyanobacteria throughout the world. It is postulated to have caused an episode of serious illnesses in Australia through treated drinking water, as well as lethal effects in livestock exposed to water from farm ponds. Toxicity included effects indicative of both hepatic and renal dysfunction. In humans, symptoms progressed from initial hepatomegaly, vomiting, and malaise to acidosis and hypokalemia, bloody diarrhea, and hyperemia in mucous membranes. Laboratory animal studies predominantly involved the intraperitoneal (i.p.) route of administration and confirmed this pattern of toxicity with changes in liver enzyme activities and histopathology consistent with hepatic injury and adverse renal effects. The aim of this study was designed to assess subchronic oral exposure (90 d) of purified CYN from 75 to 300 µg/kg/d in mouse. At the end of the dosing period, examinations of animals noted (1) elevated organ to body weight ratios of liver and kidney at all dose levels, (2) treatment-related increases in serum alanine aminotransferase (ALT) activity, (3) decreased blood urea nitrogen (BUN) and cholesterol concentrations in males, and (4) elevated monocyte counts in both genders. Histopathological alterations included hepatocellular hypertrophy and cord disruption in the liver, as well as renal cellular hypertrophy, tubule dilation, and cortical tubule lesions that were more prominent in males. A series of genes were differentially expressed including Bax (apoptosis), Rpl6 (tissue regeneration), Fabp4 (fatty acid metabolism), and Proc (blood coagulation). Males were more sensitive to many renal end points suggestive of toxicity. At the end of exposure, toxicity was noted at all dose levels, and the 75 µg/kg group exhibited significant effects in liver and kidney/body weight ratios, reduced BUN, increased serum monocytes, and multiple signs of histopathology indicating that a no-observed-adverse-effect level could not be determined for any dose level.

National Toxicology Program (NTP) pathologists are engaged in important initiatives that have significant global impact. These initiatives build on its leadership in pathology peer review and publications in the areas of toxicologic pathology, clinical pathology, and laboratory animal medicine. Over the past decade, NTP/National Institute of Environmental Health Sciences research initiatives have focused on cancer and noncancer hazard identification, with the goal of understanding cellular and molecular mechanisms of disease. New initiatives of significant global impact include the web-based nonneoplastic lesion atlas and an NTP partnership with international scientists to investigate molecular mechanisms at the whole genome level, which will be used to inform potential mechanisms of environmental exposures in human cancers. Also, we are dedicated to contributing to pathology and toxicology organizations through service on executive committees and editorial boards, participating in international projects and symposiums, and providing training for future leaders in toxicologic pathology. Herein, we provide highlights of our global contributions.

Black cohosh rhizome, available as a dietary supplement, is most commonly marketed as a remedy for dysmenorrhea and menopausal symptoms. A previous subchronic toxicity study of black cohosh dried ethanolic extract (BCE) in female mice revealed a dose-dependent ineffective erythropoiesis with a macrocytosis consistent with the condition known as megaloblastic anemia. The purpose of this study was to investigate potential mechanisms by which BCE induces these particular hematological changes. B6C3F1/N female mice (32/group) were exposed by gavage to vehicle or 1,000 mg/kg BCE for 92 days. Blood samples were analyzed for hematology, renal and hepatic clinical chemistry, serum folate and cobalamin, red blood cell (RBC) folate, and plasma homocysteine and methylmalonic acid (MMA). Folate levels were measured in liver and kidney. Hematological changes included decreased RBC count; increased mean corpuscular volume; and decreased reticulocyte, white blood cell, neutrophil, and lymphocyte counts. Blood smear evaluation revealed increased Howell-Jolly bodies and occasional basophilic stippling in treated animals. Plasma homocysteine and MMA concentrations were increased in treated animals. Under the conditions of our study, BCE administration caused hematological and clinical chemistry changes consistent with a functional cobalamin, and possibly folate, deficiency. Further studies are needed to elucidate the mechanism by which BCE causes increases in homocysteine and MMA.

Background: The peripheral leukocyte count is a biomarker of inflammation and is associated with human all-cause mortality. Although causes of acute leukocytosis are well-described, chronic environmental determinants of leukocyte number are less well understood., Objectives: We investigated the relationship between house dust endotoxin concentration and peripheral leukocyte counts in human subjects., Methods: The endotoxin–leukocyte relationship was evaluated by linear regression in the National Health and Nutrition Examination Survey (NHANES) 2005–2006 (n=6,254) and the Agricultural Lung Health Study (ALHS; n=1,708). In the ALHS, we tested for a gene [Toll-like Receptor 4 ( TLR4 ), encoding the endotoxin receptor]-by-environment interaction in the endotoxin–leukocyte relationship using regression models with an interaction term., Results: There is a statistically significant, positive association between endotoxin concentration and total leukocyte number [estimated change, 0.186×10 3 /μL (95% CI: 0.070, 0.301×10 3 /μL) per 10-fold change in endotoxin; p=0.004) in the NHANES. Similar positive associations were found for monocytes, lymphocytes, and neutrophils. Stratified analyses revealed possible effect modification by asthma and chronic obstructive pulmonary disease. We observed similar associations in the ALHS. For total leukocytes, there was suggestive evidence in the ALHS of a gene-by-environment interaction for minor allele carrier status at the TLR4 haplotype defined by rs4986790 and rs4986791 (interaction p=0.15)., Conclusions: This is, to our knowledge, the first report of an association between house dust endotoxin and leukocyte count in a national survey. The finding was replicated in a farming population. Peripheral leukocyte count may be influenced by residential endotoxin exposure in diverse settings. https://doi.org/10.1289/EHP661.

We previously observed greater ozone-induced lung function decrements in obese than non-obese women. Animal models suggest that obesity enhances ozone-induced airway reactivity and inflammation. In a controlled exposure study, we compared the acute effect of randomized 0.4ppm ozone and air exposures (2 h with intermittent light exercise) in obese (N = 20) (30

Microscopic evaluation of the types of cells present in vaginal smears has long been used to document the stages of the estrous cycle in laboratory rats and mice and as an index of the functional status of the hypothalamic-pituitary-ovarian axis. The estrous cycle is generally divided into the four stages of proestrus, estrus, metestrus, and diestrus. On cytological evaluation, these stages are defined by the absence, presence, or proportion of 4 basic cell types as well as by the cell density and arrangement of the cells on the slide. Multiple references regarding the cytology of the rat and mouse estrous cycle are available. Many contemporary references and studies, however, have relatively abbreviated definitions of the stages, are in reference to direct wet mount preparations, or lack comprehensive illustrations. This has led to ambiguity and, in some cases, a loss of appreciation for the encountered nuances of dividing a steadily moving cycle into 4 stages. The aim of this review is to provide a detailed description, discussion, and illustration of vaginal cytology of the rat and mouse estrous cycle as it appears on smears stained with metachromatic stains., (© 2015 by The Author(s).)

Background: Pregnant women who are physically active have a lower risk of preeclampsia and gestational diabetes than women who are less active. One possible mechanism is a reduction in low-grade inflammation, as measured by plasma concentrations of C-reactive protein (CRP). The association between exercise and CRP in pregnant women, however, has not been adequately investigated., Methods: A total of 537 pregnant women, enrolled around the 17th week of gestation in the Norwegian Mother and Child Cohort Study in 2003 to 2004, were studied. Self-reported recreational exercise was recalled for both 3 months before pregnancy and early pregnancy. The total energy expenditure from recreational exercise (total recreational exercise, metabolic equivalent of task [MET]-hr/week) was estimated, and low-, moderate- and vigorous-intensity exercise was defined. Plasma CRP concentrations were measured during pregnancy., Results: In adjusted linear regression models, mean CRP concentration was 1.0% lower [95% CI = -1.9% to 0.2%] with each 1 MET-hr/week of total recreational exercise before pregnancy. In addition, vigorous-intensity exercise before pregnancy was more strongly related to a reduction in CRP levels than low- or moderate-intensity exercise. However, we observed no association between recreational exercise during pregnancy and plasma CRP levels., Conclusions: Recreational exercise before pregnancy, especially vigorous exercise, may reduce the risk of maternal inflammation during pregnancy.

Sex differentiation of the male reproductive tract in mammals is driven, in part, by fetal androgen production. In utero, some phthalate esters (PEs) alter fetal Leydig cell differentiation, reducing the expression of several genes associated with steroid synthesis/transport, and consequently, lowering fetal androgen and Insl3 hormone levels. Simvastatin (SMV) is a cholesterol-lowering drug that directly inhibits HMG-CoA reductase. SMV may also disrupt steroid biosynthesis, but through a different mode of action (MOA) than the PEs. As cholesterol is a precursor of steroid hormone biosynthesis, we hypothesized that in utero exposure to SMV during the critical period of sex differentiation would lower fetal testicular testosterone (T) production without affecting genes involved in cholesterol and androgen synthesis and transport. Secondly, we hypothesized that a mixture of SMV and a PE, which may have different MOAs, would reduce testosterone levels in an additive manner. Pregnant Sprague Dawley rats were dosed orally with SMV, dipentyl phthalate (DPeP), or SMV plus DPeP from gestational days 14-18, and fetuses were evaluated on GD18. On GD18, SMV lowered fetal T production and serum triglycerides, low density lipoprotein, high density lipoprotein, and total cholesterol levels, and downregulated two genes in the fetal testis that were different from those altered by PEs. When SMV and DPeP were administered as a mixture, fetal T production was significantly reduced in an additive manner, thus demonstrating that a mixture of chemicals can induce additive effects on fetal T production even though they display different MOAs., (Published by Oxford University Press on behalf of Toxicological Sciences 2014. This work is written by (a) US Government employee(s) and is in the public domain in the US.)

Background: Perfluoroalkyl substances (PFASs) are a group of highly persistent chemicals that are widespread contaminants in wildlife and humans. Exposure to PFAS affects thyroid homeostasis in experimental animals and possibly in humans. The objective of this study was to examine the association between plasma concentrations of PFASs and thyroid stimulating hormone (TSH) among pregnant women., Methods: A total of 903 pregnant women who enrolled in the Norwegian Mother and Child Cohort Study from 2003 to 2004 were studied. Concentrations of thirteen PFASs and TSH were measured in plasma samples collected around the 18th week of gestation. Linear regression models were used to evaluate associations between PFASs and TSH., Results: Among the thirteen PFASs, seven were detected in more than 60% of samples and perfluorooctane sulfonate (PFOS) had the highest concentrations (median, 12.8 ng/mL; inter-quartile range [IQR], 10.1 -16.5 ng/mL). The median TSH concentration was 3.5 (IQR, 2.4 - 4.8) μIU/mL. Pregnant women with higher PFOS had higher TSH levels. After adjustment, with each 1 ng/mL increase in PFOS concentration, there was a 0.8% (95% confidence interval: 0.1%, 1.6%) rise in TSH. The odds ratio of having an abnormally high TSH, however, was not increased, and other PFASs were unrelated to TSH., Conclusions: Our results suggest an association between PFOS and TSH in pregnant women that is small and may be of no clinical significance.

Perfluorooctane sulfonate and perfluorooctanoic acid are perfluorinated compounds (PFCs) widely distributed in the environment. Previous studies of PFCs and birth weight are equivocal. The authors examined this association in the Norwegian Mother and Child Cohort Study (MoBa), using data from 901 women enrolled from 2003 to 2004 and selected for a prior case-based study of PFCs and subfecundity. Maternal plasma samples were obtained around 17 weeks of gestation. Outcomes included birth weight z scores, preterm birth, small for gestational age, and large for gestational age. The adjusted birth weight z scores were slightly lower among infants born to mothers in the highest quartiles of PFCs compared with infants born to mothers in the lowest quartiles: for perfluorooctane sulfonate, β = -0.18 (95% confidence interval: -0.41, 0.05) and, for perfluorooctanoic acid, β = -0.21 (95% confidence interval: -0.45, 0.04). No clear evidence of an association with small for gestational age or large for gestational age was observed. Perfluorooctane sulfonate and perfluorooctanoic acid were each associated with decreased adjusted odds of preterm birth, although the cell counts were small. Whether some of the associations suggested by these findings may be due to a noncausal pharmacokinetic mechanism remains unclear.

This manuscript is intended to provide a best practice approach to accurately and consistently assess toxicant-induced bone marrow effects of test articles. In nonclinical toxicity studies, complete blood count data in conjunction with the histological examination of the bone marrow are recommended as the foundation for assessing the effect of test articles on the hematopoietic system. This approach alone can be used successfully in many studies. However, in some situations it may be necessary to further characterize effects on the different hematopoietic lineages, either by cytological or flow cytometric evaluation of the bone marrow. Both modalities can be used successfully, and which one is selected will depend on the expertise, preference of the facility, and the nature of the change in the bone marrow. Other specialized techniques such as clonogenic assays or electron microscopy are used rarely to further characterize hematotoxicity. The indications and techniques to successfully employ histological, cytological, or flow cytometric evaluation as well as clonogenic assays and electron microscopy are reviewed., (© 2011 by the Authors, Reprinted by Permission of SAGE Publications Inc.)

The toxicity of green tea extract (GTE) was evaluated in 14-week gavage studies in male and female F344/NTac rats and B6C3F1 mice at doses up to 1,000 mg/kg. In the rats, no treatment-related mortality was noted. In the mice, treatment-related mortality occurred in male and female mice in the 1,000 mg/kg dose groups. The cause of early deaths was likely related to liver necrosis. Treatment-related histopathological changes were seen in both species in the liver, nose, mesenteric lymph nodes, and thymus. In addition, in mice, changes were seen in the Peyer's patches, spleen, and mandibular lymph nodes. The no adverse effect level (NOAEL) for the liver in both species was 500 mg/kg. In the nose of rats, the NOAEL in males was 62.5 mg/kg, and in females no NOAEL was found. No NOAEL was found in the nose of female or male mice. The changes in the liver and nose were considered primary toxic effects of GTE, while the changes in other organs were considered to be secondary effects. The nose and liver are organs with high metabolic enzyme activity. The increased susceptibility of the nose and liver suggests a role for GTE metabolites in toxicity induction.

Following a 2005 report of chromosomal damage in children with attention deficit/hyperactivity disorder (ADHD) who were treated with the commonly prescribed medication methylphenidate (MPH), numerous studies have been conducted to clarify the risk for MPH-induced genetic damage. Although most of these studies reported no changes in genetic damage endpoints associated with exposure to MPH, one recent study (Andreazza et al. [2007]: Prog Neuropsychopharmacol Biol Psychiatry 31:1282-1288) reported an increase in DNA damage detected by the Comet assay in blood and brain cells of Wistar rats treated by intraperitoneal injection with 1, 2, or 10 mg/kg MPH; no increases in micronucleated lymphocyte frequencies were observed in these rats. To clarify these findings, we treated adult male Wistar Han rats with 0, 2, 10, or 25 mg/kg MPH by gavage once daily for 28 consecutive days and measured micronucleated reticulocyte (MN-RET) frequencies in blood, and DNA damage in blood, brain, and liver cells 4 hr after final dosing. Flow cytometric evaluation of blood revealed no significant increases in MN-RET. Comet assay evaluations of blood leukocytes and cells of the liver, as well as of the striatum, hippocampus, and frontal cortex of the brain showed no increases in DNA damage in MPH-treated rats in any of the three treatment groups. Thus, the previously reported observations of DNA damage in blood and brain tissue of rats exposed to MPH for 28 days were not confirmed in this study. Additionally, no histopathological changes in brain or heart, or elevated serum biomarkers of cardiac injury were observed in these MPH-exposed rats., ((c) 2009 Wiley-Liss, Inc.)

The prevalence of human obesity and related chronic disorders such as diabetes, cardiovascular diseases, and cancer is rapidly increasing. Human studies have shown a direct relationship between obesity and infertility. The objective of the current work was to examine the effect of diet-induced obesity on male fertility and the effect of obesity on susceptibility to chemical-induced reproductive toxicity. From 5 to 30 wk of age, genetically intact male C57Bl/6J mice were fed a normal diet or one in which 60% of the kilocalories were from lard. Obese mice exhibited significant differences in the mRNA of several genes within the testes in comparison to lean males. Pparg was increased 2.2-fold, whereas Crem, Sh2b1, Dhh, Igf1, and Lepr were decreased 6.7, 1.4, 3.2, 1.6, and 7.2-fold, respectively. The fertility of male mice was compared through mating with control females. Acrylamide (AA)-induced reproductive toxicity was assessed in obese or lean males treated with water or 25 mg AA kg(-1) day(-1) via gavage for 5 days and then mated to control females. Percent body fat and weight were significantly increased in mice fed a high-fat vs. a normal diet. Obesity resulted in significant reduction in plugs and pregnancies of control females partnered with obese vs. lean males. Serum leptin and insulin levels were each approximately 5-fold higher in obese vs. age-matched lean mice. Sperm from obese males exhibited decreased motility and reduced hyperactivated progression vs. lean mice. Treatment with AA exacerbated male infertility of obese and lean mice; however, this effect was more pronounced in obese mice. Further, females partnered with AA-treated obese mice exhibited a further decrease in the percentage of live fetuses, whereas the percentage of resorptions increased. This work demonstrated that diet-induced obesity in mice caused a significant reduction in male fertility and exacerbated AA-induced reproductive toxicity and germ cell mutagenicity.

Obesity and obesity-related illnesses are global epidemics impacting the health of adults and children. The purpose of the present work is to evaluate a genetically intact obese mouse model that more accurately reflects the impact of aging on diet-induced obesity and type 2 diabetes in humans. Male C57Bl/6J mice consumed either a control diet or one in which 60% kcal were due to lard beginning at 5-6 weeks of age. Body weight and fat measurements were obtained and necropsy performed at 15, 20, 30, and 40 weeks of age. Serum chemistry, histopathology, gene expression of the liver, and renal and hepatic function were also evaluated. In concert with significant increases in percent body fat and weight, mice fed the high-fat versus control diet had significantly increased levels of serum cholesterol. At ages 20 and 30 weeks, serum glucose was significantly higher in obese versus controls, while serum insulin levels were >/=4-fold higher in obese mice at ages 30 and 40 weeks. The effect of age exacerbated the effects of consuming a high-fat diet. In addition to being hyperinsulinemic and leptin resistant, older obese mice exhibited elevated hepatic PAI-1 and downregulation of GLUT4, G6PC, IGFBP-1, and leptin receptor mRNA in the liver, steatosis with subsequent inflammation, glomerular mesangial proliferation, elevated serum ALT, AST, and BUN, and increased numbers of pancreatic islets.

Background: Insulin-like growth factor-I (IGF-I) and insulin stimulate cell proliferation in uterine leiomyoma (fibroid) tissue. We hypothesized that circulating levels of these proteins would be associated with increased prevalence and size of uterine fibroids., Methods: Participants were 35-49-year-old, randomly selected members of an urban health plan who were enrolled in the study in 1996-1999. Premenopausal participants were screened for fibroids with ultrasound. Fasting blood samples were collected. Associations between fibroids and diabetes, plasma IGF-I, IGF binding protein 3 (BP3), and insulin were evaluated for blacks (n = 585) and whites (n = 403) by using multiple logistic regression., Results: IGF-I showed no association with fibroids in blacks, but in whites the adjusted odds ratios (aORs) for both mid and upper tertiles compared with the lowest tertile were 0.6 (95% confidence intervals [CI] = 0.3-1.0 and 0.4-1.1, respectively). Insulin and diabetes both tended to be inversely associated with fibroids in blacks. The insulin association was with large fibroids; aOR for the upper insulin tertile relative to the lowest was 0.4 (0.2-0.9). The aOR for diabetes was 0.5 (0.2-1.0). Associations of insulin and diabetes with fibroids were weak for whites. Binding protein 3 showed no association with fibroids., Conclusions: Contrary to our hypothesis, high circulating IGF-I and insulin were not related to increased fibroid prevalence. Instead, there was suggestion of the opposite. The inverse association with diabetes, although based on small numbers, is consistent with previously reported findings. Future studies might investigate vascular dysfunction as a mediator between hyperinsulinemia or diabetes and possible reduced risk of fibroids.

Fifteen-day and 14-week studies of 2-methylimidazole (2MI) and 4-methylimidazole (4MI) were conducted because of widespread human exposure via ingestion of food products containing the compounds and lack of toxicity data. Groups of five male and five female Fischer rats and B6C3F1 mice were administered 2MI by dosed feed at 0, 1,200, 3,300, or 10,000 ppm or 4MI at 0, 300, 800, or 2,500 ppm for 15 days, and groups of 10 male and 10 female Fischer rats and B6C3F1 mice were administered 2MI or 4MI at 0, 625, 1,250, 2,500, 5,000 or 10,000 ppm for 14 weeks. In the 15-day studies, 2MI induced thyroid follicular-cell hyperplasia and pituitary pars-distalis hypertrophy in rats and thyroid follicular-cell hypertrophy and spleen hematopoietic-cell proliferation in mice; 4MI induced no histopathological changes in rats and mice. In the 14-week studies, 2MI increased concentrations of thyroid-stimulating hormone (TSH) and decreased those of thyroxine (T(4)) and triiodothyroxine (T(3)) in male and female rats according to the dosage. Incidences of diffuse follicular-cell hyperplasia of the thyroid gland increased significantly in male rats exposed to 1,250 ppm or greater and female rats exposed to 2,500 ppm or greater. Thyroid follicular-cell adenoma was diagnosed in two males in the 10,000-ppm group. A dose-related anemia occurred in female rats. In mice, follicular-cell hypertrophy of the thyroid gland, anemia, splenic hematopoietic-cell proliferation, and hemosiderin in kidney tubules appeared. In rats, 4MI induced tremors and ataxia in the high-dose groups. Serum T(3), T(4), and TSH levels were not altered, and no thyroid lesions occurred. Anemia, hepatocytic vacuolation, testicular degeneration, and prostatic atrophy were observed. In mice, anemia, liver cytoplasmic vacuolization, and renal degeneration and dilation occurred. Our studies demonstrated that, in rats and mice, 2MI induces thyroid hyperplasia and hypertrophy, and both 2MI and 4MI induce anemia; 2MI induces thyroid follicular-cell adenoma in male rats.

Chromium picolinate monohydrate (CPM) is a synthetic compound heavily marketed to consumers in the United States for use as a dietary supplement for muscle building and weight loss. The National Toxicology Program (NTP) tested the toxicity of this compound based on the potential for widespread consumer exposure and lack of information about its toxicity. Groups of 10 male and 10 female F344/N rats and B6C3F(1) mice were exposed to 0, 80, 240, 2000, 10,000, or 50,000 ppm CPM in feed for 13 weeks. CPM administration produced no effect on body weight gain or survival of rats or mice. Organ weights and organ/body weight ratios in exposed animals were generally unaffected by CPM. No compound-related changes in hematology and clinical chemistry parameters were observed. There were no histopathological lesions attributed to CPM in rats or mice.

The DNA demethylating agent 5-AZA-2'-deoxyxytidine (5-AZA-CdR) alters gene expression in mice exposed during developmental stages and causes malformations and growth suppression. The aim of this study was to determine if 5-AZA-CdR-induced growth retardation is associated with alterations in energy metabolism or in serum IGF-1 levels. Mice were exposed in utero to 5-AZA-CdR at gestation day 10. At postnatal day 21, exposed pups were weaned and body weights recorded. At 3 months of age, reproductive capacity was studied. At 5 months old, after body weight was recorded mice were killed and serum was collected to determine serum glucose, corticosterone, and IGF-1 levels. The body weights of both treated males and females were reduced at weaning compared with controls, but by 5 months of age, only the male body weight was affected. Reproductive capacity of males and females was reduced with males being more affected. Levels of corticosterone and glucose were not altered. Serum IGF-1 levels were lower in males exposed in utero to 5-AZA-CdR when compared to controls, but not in females, and correlated significantly with body weights. Our data suggest that the decreased levels of IGF-1 associated with the treatment could be the cause of the observed growth retardation in the in utero-exposed mice. A gender dimorphic effect, where males are more affected, is evident.

Riddelliineis a naturally occurring pyrrolizidine alkaloid found in certain poisonous rangeland plants of the western United States. In National Toxicology Program 2-year studies, riddelliine induced high incidences of hemangiosarcoma in the liver of F344/N rats (both sexes) and B6C3F1 mice (males). To understand this pathogenesis, we tested short-term effects of riddelliine. Three groups (control; 1.0 mg/kg/day, high dose used in the 2-year study; and 2.5 mg/kg/day) of seven male F344/N rats per group were terminated after 8 consecutive doses and 30 doses (6 weeks, excluding weekends). Serum vascular endothelial growth factor (VEGF), histological, immunohistochemical [factor VIII-related antigen/von Willebrand factor (fVIII-ra/vWf)], VEGF, VEGF receptor-2 (VEGFR2), glutathione S-transferase-pi, S-phase (BrdU), p53, apoptosis, and ultrastructural evaluations were performed on the liver. Following 8 doses of 1.0 and 2.5 mg/kg/day, increased numbers of apoptotic and S-phase nuclei appeared in hepatocytes and endothelial cells. Following 30 doses of 1.0 and 2.5 mg/kg/day, hepatocytes exhibited reduced mitosis, fewer S-phase nuclei, increased hypertrophy, and fatty degeneration, while endothelial cells showed karyomegaly, cytomegaly, decreased apoptosis, more S-phase nuclei, and p53 positivity. Hepatocytes of treated animals expressed higher VEGF immunopositivity. That altered endothelial cells were fVIII-ra/vWf and VEGFR2 positive confirmed their identity. These changes may have promoted hemangiosarcoma development upon long-term exposure through endothelial adduct formation, apoptosis, proliferation of endothelial cells having undamaged and/or damaged DNA, and mutation. Endothelial proliferation may also have been promoted through endothelial arrest at S phase, which was associated with endothelial karyo- and cytomegaly, resulting in hepatocytic hypoxia, triggering VEGF induction.

Chlorine dioxide (ClO2) is an effective drinking water disinfectant, but sodium chlorate (NaClO3) has been identified as a potentially harmful disinfection by-product. Studies were performed to describe the development of thyroid lesions in animals exposed to NaClO3 in the drinking water. Male and female F344 rats and B6C3F1 mice were exposed to 0, 0.125, 0.25, 0.5, 1.0, or 2.0 g/L NaClO3 for 21 days. Additional male F344 rats were exposed to 0, 0.001. 0.01. 0.1, 1.0. or 2.0 g/L NaClO3 for 90 days. Female F344 rats were exposed to 0, 0.5, 1.0, 2.0, 4.0, or 6.0 g/L of NaClO3 for 105 days. Thyroid tissues were processed by routine methods for light microscopic examination, and follicular cell hyperplasia was diagnosed using a novel method. Thyroid hormone levels were altered significantly after 4 and 21 days. NaClO, treatment induced a concentration-dependent increase in the incidence and severity of thyroid follicular cell hyperplasia. Male rats are more sensitive to the effects of NaClO3 treatment than females. Follicular cell hyperplasia was not present in male or female B6C3F1 mice. These data can be used to estimate the human health risk that would be associated with using ClO2, rather than chlorine, to disinfect drinking water.

Understanding the pathology of the female reproductive system with respect to toxicology requires a basic understanding of morphology and function of the system over time because the nature of the female reproductive system is cyclical. Thus, the morphology and the endocrinology is dependent on age and time, as form follows function and function follows form. The life span of the rodent is used as an outline to present an overview of key morphological and endocrinological events important for toxicologic pathologists to consider in study evaluations. Environmental and pharmaceutical compounds differentially impact the organs individually and/or the system in its entirety in a time- and dose-dependent way. Examples are used to illustrate the consequences of exposures at different times and with different outcomes.