The polyfluorinated alkyl substance (PFAS) Nafion BP2 (1,1,2,2-tetrafluoro-2-[1,1,1,2,3,3-hexafluoro-3-(1,1,2,2-tetrafluoroethoxy)propan-2-yl]oxyethane-1-sulfonic acid) has been detected in surface and ground water, as well as in the blood of people living near PFAS manufacturing facilities. Given that very little is known about the potential toxicity of Nafion BP2 and safe exposure levels have not yet been determined, we performed a benchmark dose analysis of phenotypic and genomic effects in mice. Male and female Balb-c mice were exposed daily to Nafion BP2 at multiple doses for 7 d by oral gavage. Full-genome transcript profiling showed that Nafion BP2 in both sexes activates a number of transcription factors linked to liver toxicity, including constitutive androstane receptor (CAR), pregnane X receptor, and NRF2, but unlike other long-chain PFAS, there was no activation of peroxisome proliferator-activated receptor α. Nafion BP2 caused hepatic steatosis in both sexes. Benchmark dose (BMD) estimates for 15 non-genomic effects were 0.25 mg/kg/d and above. BMDs for transcriptional effects were 0.04 mg/kg/d and above. The most sensitive gene sets in both males and females were related to effects on xenobiotic metabolism and the cell cycle, which are plausibly related at a mechanistic level to the activation of CAR. The xenobiotic metabolism and cell cycle findings were largely consistent when dose values based on internal dose were employed in the analysis. These values, along with the identification of molecular targets linked to hazards, may facilitate the determination of human health guidance for Nafion BP2.

Per- and polyfluoroalkyl substances (PFAS) are organic chemicals with wide industrial and consumer uses. They are found ubiquitously at low levels in the environment and are detectable in humans and wildlife. Perfluorobutane Sulfonate (PFBS) is a short-chained PFAS used to replace perfluorooctane sulfonate in commerce. In general, the rate of clearance for the short-chained PFAS is faster than that for the long-chained congeners. This study evaluated the pharmacokinetic properties of PFBS and its hepatic transcriptional responses in CD-1 mice. Males and females were given PFBS by oral gavage at 30 or 300 mg/kg; controls received 0.5 % Tween-20 vehicle. Trunk blood was collected at 0.5, 1, 2, 4, 8, 16 and 24 h thereafter; liver and kidney were also harvested. Serum and tissue concentrations of PFBS were determined by HPLC-MS-MS. Expression of several hepatic nuclear receptor target genes was determined by qPCR. The half-life of PFBS was estimated as 5.8h in the males and 4.5 h in the females. Tmax was reached within 1 - 2 h. Volume of distribution was similar between the two sexes (0.32 - 0.40 L/kg). The rate of PFBS clearance was linear with exposure doses. Within 24 h, serum PFBS declined to less than 5 % of Cmax. PFBS was detected in liver or kidney, although tissue levels of the chemical were only a fraction of those in serum. At 24 h after administration of 300 mg/kg PFBS, elevated expression of several hepatic genes targeted for PPAR alpha, PPARy, and PXR but not by AhR, LXR or CAR was observed, with responses indistinguishable between males and females. Little to no transcriptional response was seen with the 30 mg/kg dose. The short serum half-lives of PFBS (4 - 5 h) in mice were comparable to those reported in rats. Although detection of PFBS in liver was low compared to that in serum even at the 300 mg/kg dose, the tissue level was sufficient to activate several hepatic nuclear receptors, which may represent an acute response to the chemical at a high dose.

BACKGROUND:Cleft palate (CP) is a common birth defect, occurring in an estimated 1 in 1,000 births worldwide. The secondary palate is formed by paired palatal shelves, consisting of a mesenchymal core with an outer layer of epithelial cells that grow toward each other, attach, and fuse. One of the mechanisms that can cause CP is failure of fusion, that is, failure to remove the epithelial seam between the palatal shelves to allow the mesenchyme confluence. Epidermal growth factor (EGF) plays an important role in palate growth and differentiation, while it may impede fusion. METHODS:We developed a 3D organotypic model using human mesenchymal and epithelial stem cells to mimic human embryonic palatal shelves, and tested the effects of human EGF (hEGF) on proliferation and fusion. Spheroids were generated from human umbilical-derived mesenchymal stem cells (hMSCs) directed down an osteogenic lineage. Heterotypic spheroids, or organoids, were constructed by coating hMSC spheroids with extracellular matrix solution followed by a layer of human progenitor epithelial keratinocytes (hPEKs). Organoids were incubated in co-culture medium with or without hEGF and assessed for cell proliferation and time to fusion. RESULTS:Osteogenic differentiation in hMSC spheroids was highest by Day 13. hEGF delayed fusion of organoids after 12 and 18 hr of contact. hEGF increased proliferation in organoids at 4 ng/ml, and proliferation was detected in hPEKs alone. CONCLUSION:Our results show that this model of human palatal fusion appropriately mimics the morphology of the developing human palate and responds to hEGF as expected.

Perfluoroalkyl acids (PFAAs) are ubiquitous and persistent environmental contaminants. Compounds such as perfluoroocanoic acid (PFOA), perfluorooctane sulfonate (PFOS), perfluorononanoic acid (PFNA), and perfluorohexane sulfonate (PFHxS) are readily found in the tissues of humans and wildlife. While PFOA and PFOS have been the subject of numerous studies since they were first described over a decade ago, less is known about the biological activity of PFHxS and PFNA. Most PFAAs are activators of peroxisome proliferator-activated receptor α (PPARα), although the biological effects of these compounds are likely mediated by other factors in addition to PPARα. To evaluate the effects of PFHxS and PFNA, male wild-type and Pparα-null mice were dosed by oral gavage with PFHxS (3 or 10 mg/kg/day), PFNA (1 or 3 mg/kg/day), or vehicle for 7 days, and liver gene expression was evaluated by full-genome microarrays. Gene expression patterns were then compared to historical in-house data for PFOA and PFOS in addition to the experimental hypolipidemic agent, WY-14,643. While WY-14,643 altered most genes in a PPARα-dependent manner, approximately 11–24% of regulated genes in PFAA-treated mice were independent of PPARα. The possibility that PFAAs regulate gene expression through other molecular pathways was evaluated. Using data available through a microarray database, PFAA gene expression profiles were found to exhibit significant similarity to profiles from mouse tissues exposed to agonists of the constitutive activated receptor (CAR), estrogen receptor α (ERα), and PPARγ. Human PPARγ and ERα were activated by all four PFAAs in trans-activation assays from the ToxCast screening program. Predictive gene expression biomarkers showed that PFAAs activate CAR in both genotypes and cause feminization of the liver transcriptome through suppression of signal transducer and activator of transcription 5 B (STAT5B). These results indicate that, in addition to activating PPARα as a primary target, PFAAs also have the potential to activate CAR, PPARγ, and ERα as well as suppress STAT5B.

Persistent presence of perfluoroalkyl acids (PFAAs) in the environment is due to their extensive use in industrial and consumer products, and their slow decay. Biochemical tests in rodent demonstrated that these chemicals are potent modifiers of lipid metabolism and cause hepatocellular steatosis. However, the molecular mechanism of PFAAs interference with lipid metabolism remains to be elucidated. Currently, two major hypotheses are that PFAAs interfere with mitochondrial beta-oxidation of fatty acids and/or they affect the transcriptional activity of peroxisome proliferator-activated receptor α (PPARα) in liver. To determine the ability of structurally-diverse PFAAs to cause steatosis, as well as to understand the underlying molecular mechanisms, wild-type (WT) and PPARα-null mice were treated with perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), or perfluorohexane sulfonate (PFHxS), by oral gavage for 7 days, and their effects were compared to that of PPARα agonist WY-14643 (WY), which does not cause steatosis. Increases in liver weight and cell size, and decreases in DNA content per mg of liver, were observed for all compounds in WT mice, and were also seen in PPARα-null mice for PFOA, PFNA, and PFHxS, but not for WY. In Oil Red O stained sections, WT liver showed increased lipid accumulation in all treatment groups, whereas in PPARα-null livers, accumulation was observed after PFNA and PFHxS treatment, adding to the burden of steatosis observed in control (untreated) PPARα-null mice. Liver triglyceride (TG) levels were elevated in WT mice by all PFAAs and in PPARα-null mice only by PFNA. In vitro β-oxidation of palmitoyl carnitine by isolated rat liver mitochondria was not inhibited by any of the 7 PFAAs tested. Likewise, neither PFOA nor PFOS inhibited palmitate oxidation by HepG2/C3A human liver cell cultures. Microarray analysis of livers from PFAAs-treated mice indicated that the PFAAs induce the expression of the lipid catabolism genes, as well as those involved in fatty acid and triglyceride synthesis, in WT mice and, to a lesser extent, in PPARα-null mice. These results indicate that most of the PFAAs increase liver TG load and promote steatosis in mice We hypothesize that PFAAs increase steatosis because the balance of fatty acid accumulation/synthesis and oxidation is disrupted to favor accumulation.

Perfluorononanoic acid (PFNA) is a ubiquitous and persistent environmental contaminant. Although its levels in the environment and in humans are lower than those of perfluorooctane sulfonate (PFOS) or perfluorooctanoic acid (PFOA), a steady trend of increases in the general population in recent years has drawn considerable interest and concern. Previous studies with PFOS and PFOA have indicated developmental toxicity in laboratory rodent models. The current study extends the evaluation of these adverse outcomes to PFNA in mice. PFNA was given to timed-pregnant CD-1 mice by oral gavage daily on gestational day 1-17 at 1, 3, 5 or 10mg/kg; controls received water vehicle. Dams given 10mg/kg PFNA could not carry their pregnancy successfully and effects of this dose group were not followed. Similar to PFOS and PFOA, PFNA at 5mg/kg or lower doses produced hepatomegaly in the pregnant dams, but did not affect the number of implantations, fetal viability, or fetal weight. Mouse pups were born alive and postnatal survival in the 1 and 3mg/kg PFNA groups was not different from that in controls. In contrast, although most of the pups were also born alive in the 5mg/kg PFNA group, 80% of these neonates died in the first 10 days of life. The pattern of PFNA-induced neonatal death differed somewhat from those elicited by PFOS or PFOA. A majority of the PFNA-exposed pups survived a few days longer after birth than those exposed to PFOS or PFOA, which typically died within the first 2 days of postnatal life. Surviving neonates exposed to PFNA exhibited dose-dependent delays in eye opening and onset of puberty. In addition, increased liver weight seen in PFNA-exposed offspring persisted into adulthood and was likely related to the persistence of the chemical in the tissue. Evaluation of gene expression in fetal and neonatal livers revealed robust activation of peroxisome proliferator-activated receptor-alpha (PPARα) target genes by PFNA that resembled the responses of PFOA. Our results indicate that developmental toxicity of PFNA in mice is comparable to that of PFOS and PFOA, and that these adverse effects are likely common to perfluoroalkyl acids that persist in the body.

While perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) have been studied at length, less is known about the biological activity of other perfluoroalkyl acids (PFAAs) detected in the environment. Using a transient transfection assay developed in COS-1 cells, our group has previously evaluated a variety of PFAAs for activity associated with activation of peroxisome proliferator-activated receptor alpha (PPARα). Here we use primary heptatocytes to further assess the biological activity of a similar group of PFAAs using custom designed Taqman Low Density Arrays. Primary mouse and human hepatoyctes were cultured for 48h in the presence of varying concentrations of 12 different PFAAs or Wy14,643, a known activator of PPARα. Total RNA was collected and the expression of 48 mouse or human genes evaluated. Gene selection was based on either in-house liver microarray data (mouse) or published data using primary hepatocytes (human). Gene expression in primary mouse hepatocytes was more restricted than expected. Genes typically regulated in whole tissue by PPARα agonists were not altered in mouse cells including Acox1, Me1, Acaa1a, Hmgcs1, and Slc27a1. Cyp2b10, a gene regulated by the constitutive androstane receptor and a transcript normally up-regulated by in vivo exposure to PFAAs, was also unchanged in cultured mouse hepatocytes. Cyp4a14, Ehhadh, Pdk4, Cpt1b, and Fabp1 were regulated as expected in mouse cells. A larger group of genes were differentially expressed in human primary hepatocytes, however, little consistency was observed across compounds with respect to which genes produced a significant dose response making the determination of relative biological activity difficult. This likely reflects weaker activation of PPARα in human versus rodent cells as well as variation among individual cell donors. Unlike mouse cells, CYP2B6 was up-regulated in human hepatocytes by a number of PFAAs as was PPARδ. Rankings were conducted on the limited dataset. In mouse hepatocytes, the pattern was similar to that previously observed in the COS-1 reporter cell assay. With the exception of PFHxA, longer chain PFAA carboxylates were the most active. The pattern was similar in human hepatocytes, although PFDA and PFOS showed higher activity than previously observed while PFOA showed somewhat less activity. These data reflect inherent challenges in using primary hepatocytes to predict toxicological response.

In order to compare between in vivo toxicity studies, dosimetry is needed to translate study-specific dose regimens into dose metrics such as tissue concentration. These tissue concentrations may then be compared with in vitro bioactivity assays to perhaps identify mechanisms relevant to the lowest observed effect level (LOEL) dose group and the onset of the observed in vivo toxicity. Here, we examine the perfluorinated compounds (PFCs) perfluorooctanoate (PFOA) and perfluorooctanesulfonate (PFOS). We analyzed 9 in vivo toxicity studies for PFOA and 13 in vivo toxicity studies for PFOS. Both PFCs caused multiple effects in various test species, strains, and genders. We used a Bayesian pharmacokinetic (PK) modeling framework to incorporate data from 6 PFOA PK studies and 2 PFOS PK studies (conducted in 3 species) to predict dose metrics for the in vivo LOELs and no observed effect levels (NOELs). We estimated PK parameters for 11 combinations of chemical, species, strain, and gender. Despite divergent study designs and species-specific PK, for a given effect, we found that the predicted dose metrics corresponding to the LOELs (and NOELs where available) occur at similar concentrations. In vitro assay results for PFOA and PFOS from EPA's ToxCast project were then examined. We found that most in vitro bioactivity occurs at concentrations lower than the predicted concentrations for the in vivo LOELs and higher than the predicted concentrations for the in vivo NOELs (where available), for a variety of nonimmunological effects. These results indicate that given sufficient PK data, the in vivo LOELs dose regimens, but not necessarily the effects, could have been predicted from in vitro studies for these 2 PFCs.

The exponential rise in people living longer but requiring residential care is adding pressure to already overstretched aged care nurses. Consequently, a person-centred care culture in residential care remains aspirational, rather than a reality. For nursing students in Australia and elsewhere, clinical placements in aged care facilities are under-utilised due to negative perceptions about the likelihood for learning. Creative strategies to engage students to safely challenge ageist thinking and to inspire enthusiasm for learning in this context are needed.The purpose of this thematic review of the literature is to better understand challenges related to learning in aged care settings and identify innovative strategies to enhance nursing student learning experiences in residential aged care placements.A literature review was undertaken in 2019 using CINAHL, PUBMED, Elsevier, Medline, ProQuest and Google Scholar. The search was limited to papers that were peer reviewed, in English, and published between 2001 and the date of review (mid-2019) in order to situate the review in the new millennium.47 articles and books were included in the review that introduce solutions and innovative strategies that could be used to improve students' attitudes to learning in aged care and from older people. The literature review was categorized into three main themes, including: barriers to working with older people; the need for pedagogical change to foster empathy; and innovative strategies to address barriers.These themes are useful to consider in designing engaging learning and teaching for nursing students to be effective in working in aged care.

Sequential 28-day and 90-day oral toxicity studies were performed in male and female rats with ammonium perfluorobutyrate (NH(4)(+)PFBA) at doses up to 150 and 30mg/kg-d, respectively. Ammonium perfluorooctanoate was used as a comparator at a dose of 30mg/kg-d in the 28-day study. Female rats were unaffected by NH(4)(+)PFBA. Effects in males included: increased liver weight, slight to minimal hepatocellular hypertrophy; decreased serum total cholesterol; and reduced serum thyroxin with no change in serum thyrotropin. During recovery, liver weight, histological, and cholesterol effects were resolved. Results of RT-qPCR were consistent with increased transcriptional expression of the xenosensor nuclear receptors PPARα and CAR as well as the thyroid receptor, and decreased expression of Cyp1A1 (Ah receptor-regulated). No observable adverse effect levels (NOAELs) were 6 and >150mg/kg-d for male and female rats in the 28-day study and 6 and >30mg/kg-d in the 90-dat study, respectively.

Parent polychlorinated biphenyls (PCBs) have been shown to induce cellular oxidative stress. However, the effects of PCB active metabolites have not been extensively investigated. Parent PCBs are first converted to hydroquinone metabolites via cytochrome P-450-catalyzed hydroxylation, and the hydroquinone metabolites are then further oxidized into the corresponding quinone metabolites. Quinones are responsible for a wide range of toxic effects because of their high reactivity. Previous studies have suggested that reactive oxygen species (ROS) play important roles in multiple toxic mechanisms. In this context, the present study was undertaken to investigate oxidative stress resulting from treatment with PCB quinones in HepG2 cells. The protective effects resulting from co-administration of dihydrolipoic acid (DH-LA) were also investigated. We have found that exposure to PCB quinones leads to: (1) a decrease in cell viability; (2) an increase in both the total ROS production and superoxide production; (3) only 3Cl-PCBQ caused significant increase in the thiobarbituric acid reactive substances (TBARS) level; (4) an increase in SOD activity and a decrease in catalase activity; and (5) a decrease in GST activity and GSH level. We have also found that quinones possessing a higher number of chlorine atoms on the quinone ring display a greater activity and that DH-LA is an effective protective agent as it diminishes PCB quinone-induced cellular oxidative stress.

Amotivation is a central feature of psychosis that can lead to underperformance on a variety of tasks, including neurocognitive testing; however, there is some evidence that neurocognitive impairments resulting from low effort can be ameliorated with the use of monetary reinforcement. While cross-sectional data has also shown that amotivation is associated with social cognitive performance, limited research has examined the directionality of this relationship, and whether monetary reinforcement can similarly reduce these impairments. In the present study, 35 patients with early psychosis and 35 community controls were randomized to either a reward condition in which they received monetary reinforcement for every correct response on a theory of mind (ToM) task, or a non-reward condition in which no feedback was provided. A significant group by condition interaction emerged after adjusting for premorbid intelligence and global neurocognition, F(1, 63) = 7.76, p = .007. Post-hoc analyses revealed that performance on the ToM task was similar across conditions for controls, whereas early psychosis patients in the reward condition had clinically and statistically significant differences in ToM performance compared to patients in the non-reward condition. These results suggest that social cognitive task performance may underrepresent actual ability in the early stages of psychosis. Future research is needed to discriminate the relative effects of monetary reinforcement, corrective feedback, and/or a combination of these factors to better understand performance differences between conditions, which appeared to be unique to early psychosis patients.

Salinity could damage cellular membranes through overproduction of reactive oxygen species (ROS), while antioxidant capacities play a vital role in protecting plants from salinity caused oxidative damages. The objective of this study was to investigate the toxic effect of salt on the antioxidant enzyme activities, isoforms and gene expressions in perennial ryegrass (Lolium perenne L.). Salt-tolerant ‘Quickstart II’ and salt-sensitive ‘DP1′ were subjected to 0 and 250 mM NaCl for 12 d. Salt stress increased the content of lipid peroxidation (MDA), electrolyte leakage (EL) and hydrogen peroxide (H2O2), to a greater extent in salt-sensitive genotype. Salt-stressed plant leaves exhibited a greater activity of superoxide dismutase (SOD, EC 1.15.1.1), peroxidase (POD, EC 1.11.1.7), ascorbate peroxidase (APX, EC 1.11.1.11) at 4 d after treatment (DAT), but a lower level of enzyme activity at 8 and 12 d, when compared to the control. Catalase (CAT, EC 1.11.1.6) activity was greater at 4 DAT and thereafter decreased in salt tolerant genotype relative to the control, whereas lower than the control during whole experiment period for salt-sensitive genotype. There were different patterns of five isoforms of SOD, POD and two isoforms of APX between two genotypes. Antioxidant gene expression was positively related to isoenzymatic and total enzymatic activities during 12-d salt-treated leaves of two genotypes, with a relatively higher level in salt-tolerant genotype. Thus, salt tolerance could be related to the constitutive/induced antioxidant gene, leading to more efficient enzyme stimulation and protection in perennial ryegrass.

Perfluorononanoic acid (PFNA) is a fluorinated organic chemical found at low levels in the environment, but is detectable in humans and wildlife. The present study compared the pharmacokinetic properties of PFNA in two laboratory rodent species. Male and female Sprague-Dawley rats were given a single dose of PFNA by oral gavage at 1, 3, or 10mg/kg, and blood was collected from the tail vein at 1, 2, 3, 4, 7, 16, 21, 28, 35, 42 and 50 days after treatment. In addition, livers and kidneys were collected for PFNA analysis at the terminal time point. CD-1 mice were given a single oral dose of PFNA of 1 or 10mg/kg, and 4 males and 4 females were killed at similar time intervals; trunk blood, liver and kidney were collected. Serum and tissue concentrations of PFNA were determined by LC-MS/MS. Serum elimination of PFNA is by and large linear with exposure doses in the rat; however, like PFOA, a major sex difference in the rate of elimination is observed, with an estimated half-life of 30.6 days for males and 1.4 days for females. PFNA is stored preferentially in the liver but not in the kidneys. In the mouse, the rates of PFNA serum elimination are non-linear with exposure dose and are slightly faster in females than males, with terminal estimated serum half-life of 25.8-68.4 days and 34.3-68.9 days, respectively. PFNA is also stored preferentially in the mouse liver but not in the kidneys. Hepatic uptake appears to be more efficient and storage capacity greater in male mice than in females. These data suggest that (1) PFNA is more persistent in the mouse than in the rat; (2) there is a major sex difference in the serum elimination of PFNA in the rat, but much less so in the mouse; and (3) there is a significantly higher hepatic accumulation of PFNA in male mice than in females.

PPARs regulate metabolism and can be activated by environmental contaminants such as perfluorooctanoic acid (PFOA). PFOA induces neonatal mortality, developmental delay, and growth deficits in mice. Studies in genetically altered mice showed that PPARα is required for PFOA-induced developmental toxicity. In this study, pregnant CD-1 mice were dosed orally from GD1 to 17 with water or 5mg PFOA/kg to examine PPARα, PPARβ, and PPARγ expression and profile the effects of PFOA on PPAR-regulated genes. Prenatal and postnatal liver, heart, adrenal, kidney, intestine, stomach, lung, spleen, and thymus were collected at various developmental ages. RNA and protein were examined using qPCR and Western blot analysis. PPAR expression varied with age in all tissues, and in liver PPARα and PPARγ expression correlated with nutritional changes as the pups matured. As early as GD14, PFOA affected expression of genes involved in lipid and glucose homeostatic control. The metabolic disruption produced by PFOA may contribute to poor postnatal survival and persistent weight deficits of CD-1 mouse neonates.

Perfluorooctane sulfonate (PFOS) is a perfluoroalkyl acid (PFAA) and a persistent environmental contaminant found in the tissues of humans and wildlife. Although blood levels of PFOS have begun to decline, health concerns remain because of the long half-life of PFOS in humans. Like other PFAAs, such as, perfluorooctanoic acid (PFOA), PFOS is an activator of peroxisome proliferator-activated receptor-alpha (PPARα) and exhibits hepatocarcinogenic potential in rodents. PFOS is also a developmental toxicant in rodents where, unlike PFOA, its mode of action is independent of PPARα. Wild-type (WT) and PPARα-null (Null) mice were dosed with 0, 3, or 10 mg/kg/day PFOS for 7 days. Animals were euthanized, livers weighed, and liver samples collected for histology and preparation of total RNA. Gene profiling was conducted using Affymetrix 430_2 microarrays. In WT mice, PFOS induced changes that were characteristic of PPARα transactivation including regulation of genes associated with lipid metabolism, peroxisome biogenesis, proteasome activation, and inflammation. PPARα-independent changes were indicated in both WT and Null mice by altered expression of genes related to lipid metabolism, inflammation, and xenobiotic metabolism. Such results are similar to studies done with PFOA and are consistent with modest activation of the constitutive androstane receptor (CAR), and possibly PPARγ and/or PPARβ/δ. Unique treatment-related effects were also found in Null mice including altered expression of genes associated with ribosome biogenesis, oxidative phosphorylation, and cholesterol biosynthesis. Of interest was up-regulation of Cyp7a1, a gene which is under the control of various transcription regulators. Hence, in addition to its ability to modestly activate PPARα, PFOS induces a variety of PPARα-independent effects as well.

Peroxisome proliferator-activated receptors (PPARs) regulate lipid and glucose homeostasis, are targets of pharmaceuticals, and are also activated by environmental contaminants. Almost nothing is known about expression of PPARs during human fetal development. This study examines expression of PPAR alpha, beta, and gamma mRNA and protein in human fetal tissues. With increasing fetal age, mRNA expression of PPAR alpha and beta increased in liver, but PPAR beta decreased in heart and intestine, and PPAR gamma decreased in adrenal. Adult and fetal mean expression of PPAR alpha, beta, and gamma mRNA did not differ in intestine, but expression was lower in fetal stomach and heart. PPAR alpha and beta mRNA in kidney and spleen, and PPAR gamma mRNA in lung and adrenal were lower in fetal versus adult. PPAR gamma in liver and PPAR beta mRNA in thymus were higher in fetal versus adult. PPAR alpha protein increased with fetal age in intestine and decreased in lung, kidney, and adrenal. PPAR beta protein in adrenal and PPAR gamma in kidney decreased with fetal age. This study provides new information on expression of PPAR subtypes during human development and will be important in evaluating the potential for the developing human to respond to PPAR environmental or pharmaceutical agonists.

Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) are members of a family of perfluorinated compounds. Both are environmentally persistent and found in the serum of wildlife and humans. PFOS and PFOA are developmentally toxic in laboratory rodents. Exposure to these chemicals in utero delays development and reduces postnatal survival and growth. Exposure to PFOS on the last 4 days of gestation in the rat is sufficient to reduce neonatal survival. PFOS and PFOA are weak agonists of peroxisome proliferator activated receptor-alpha (PPAR alpha). The reduced postnatal survival of neonatal mice exposed to PFOA was recently shown to depend on expression of PPAR alpha. This study used PPAR alpha knockout (KO) and 129S1/SvlmJ wild type (WT) mice to determine if PPAR alpha expression is required for the developmental toxicity of PFOS. After mating overnight, the next day was designated gestation day (GD) 0. WT females were weighed and dosed orally from GD15 to 18 with 0.5% Tween-20, 4.5, 6.5, 8.5, or 10.5mg PFOS/kg/day. KO females were dosed with 0.5% Tween-20, 8.5 or 10.5mg PFOS/kg/day. Dams and pups were observed daily and pups were weighed on postnatal day (PND) 1 and PND15. Eye opening was recorded from PND12 to 15. Dams and pups were killed on PND15, body and liver weights recorded, and serum collected. PFOS did not affect maternal weight gain or body or liver weights of the dams on PND15. Neonatal survival (PND1-15) was significantly reduced by PFOS in both WT and KO litters at all doses. WT and KO pup birth weight and weight gain from PND1 to 15 were not significantly affected by PFOS exposure. Relative liver weight of WT and KO pups was significantly increased by the 10.5mg/kg dose. Eye opening of PFOS-exposed pups was slightly delayed in WT and KO on PND13 or 14, respectively. Because results in WT and KO were comparable, it is concluded that PFOS-induced neonatal lethality and delayed eye opening are not dependent on activation of PPAR alpha.

Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) are environmental contaminants found in the tissues of humans and wildlife. They are activators of peroxisome proliferator-activated receptor-alpha (PPAR alpha) and exhibit hepatocarcinogenic potential in rats. PFOS and PFOA are also developmental toxicants in rodents and PFOS has been shown to induce pulmonary deficits in rat offspring. Pregnant CD-1 mice were dosed with 0, 5, or 10mg/kg PFOS from gestation days 1-17. Transcript profiling was conducted on the fetal liver and lung. Results were contrasted to data derived from a previous PFOA study. PFOS-dependent changes were primarily related to activation of PPAR alpha. No remarkable differences were found between PFOS and PFOA. Given that PPAR alpha signaling is required for neonatal mortality in PFOA-treated mice but not those exposed to PFOS, the neonatal mortality observed for PFOS may reflect functional deficits related to the physical properties of the chemical rather than to transcript alterations.

p,p′-Dichlordiphenyldichloroethylene (DDE) is a metabolite of the insecticide dichlorodiphenyltrichloroethane (DDT), an organochloride which was massively used from its discovery in 1939 until the early 1970's. Due to the tremendous half-life of DDT and DDE, both substances are to date environmentally relevant. Furthermore, DDT is still employed in many African countries in the context of the WHO's antimalaria campaign. In amphibians, DDE was found to act as antiandrogenic endocrine disrupting chemical (EDC), whereas in other species DDE was found to act as an estrogen. To determine the mode of action (MOA) of DDE in adult male Xenopus laevis, we exposed adult male frogs to different concentrations of DDE, as well as to the estrogenic EDC ethinylestradiol (EE2) and the antiandrogenic fungicide vinclozolin (VIN) for four consecutive nights. We then analyzed the mate calling behavior, which was previously shown to be affected by (anti)androgenic and (anti)estrogenic EDC in a MOA-specific manner, in order to assess whether DDE exposure results in estrogen-specific or antiandrogen-specific alterations of the mate calling behavior. Our results demonstrate that DDE alters the reproductive behavior of male X. laevis. Lowered sexual arousal of exposed males was indicated by a decreased production of advertisement calls and higher amounts of calls that suggest a sexually unaroused state of the males. Our results further indicate that DDE can display both, estrogenic and antiandrogenic MOA, either of which can have adverse effects on reproductive physiology and behavior in X. laevis. The disruption of the affected mating behavior, which is crucial for a successful reproduction, might result in a reduced reproductive success of DDE exposed animals.