Acaricidal properties of ylang-ylang oil and star anise oil against nymphs of Ixodes ricinus (Acari: Ixodidae).

Ylang-ylang oil (YYO) from Cananga odorata (Lam.) Hook.f. & Thomson and star anise oil (SAO) from Illicium verum Hook.f. were tested at four concentrations 0.05, 0.1, 0.2, 0.4 µl/cm2. Mortality rates were obtained by counting dead nymphs at 30-min intervals during the first 5 h after the start of exposure and then at 24, 48 and 72 h. Mortality increased with increasing oil concentration and time of exposure. The two highest concentrations of YYO (0.2, 0.4 µl/cm2) gave maximum lethal concentrations (LC) of 50 and 95% mortality after 4.5 h exposure. Mortality of 95% was obtained after 24 h with the next highest dose (0.1 µl/cm2), whereas LC95 required 3 days with the lowest YYO (0.05 µl/cm2). The lethal effect time (LT) was correlated with the duration of exposure, with a significant effect at 0.4 µl YYO/cm2 after 3 h' (LT50 = 3.2 h, LT95 = 4.3 h). In contrast, only the highest concentration of SAO, 0.4 µl SAO/cm2, showed increasing mortality with time of exposure. This reached LT50 after 10 h and LT95 after 24 h. However, with the lower concentration (0.2 µl/cm2) 50% mortality was reached after 24 h and 100% at 72 h. At to the lowest concentration of SAO (0.1 µl/cm2), 67% mortality after 48 h. The study indicates that YYO and SAO exhibit strong acaricidal properties against nymphs of I. ricinus and suggest that both YYO and SAO should be evaluated as potentially useful in the control of ticks.

Combination effects of pyrethroids and neonicotinoids on development and survival of Chironomus riparius.

Standard ecotoxicological risk assessments are conducted on individual substances, however monitoring of streams in agricultural areas has shown that pesticides are rarely present alone. In fact, brief but intense pulse events such as storm water runoff and spray drift during application subject freshwater environments to complex mixtures of pesticides at high concentrations. This study investigates the potential risks to non-target aquatic organisms exposed to a brief but intense mixture of the neonicotinoid pesticides imidacloprid and thiacloprid and the pyrethroid pesticides deltamethrin and esfenvalerate, compared to single substance exposure. All four of these pesticides have been detected in surface waters at concentrations higher than benchmark values and both classes of pesticides are known to exert adverse effects on non-target aquatic organisms under single substance exposure scenarios. First instar midge larvae of the non-target aquatic organism, Chironomus riparius, were exposed to combinations of these four pesticides at 50% of their LC50 (96 h) values in a 1h pulse. They were then reared to adulthood in uncontaminated conditions and assessed for survival, development time and fecundity. Our results show that the risk of disruption to survival and development of non-target aquatic organisms under this scenario is not negligible on account of the significant increases in mortality of C. riparius found in the majority of the pesticide exposures and the delays in development after pyrethroid exposure. While none of the deleterious effects appear to be amplified by combination of the pesticides, there is some evidence for antagonism. No effects on fecundity by any of the pesticide treatments were observed.

Bone mineral density in Swedish otters (Lutra lutra) in relation to PCB and DDE concentrations.

The aim of this study is to elucidate if DDE (dichlorodiphenyldichloroethylene) or PCB (polybrominated diphenyls), are responsible for the pathological alterations observed in Swedish otter bone tissues. Femurs from 86 male otters collected between 1832 and 2004 were measured using peripheral quantitative computed tomography (pQCT). Some otters had very high and others fairly low concentrations of OCs (ranging between 1.4-970 mg SigmaPCB/kg l.w. and 0.0-24 mg DDE/kg l.w. in muscle tissue). Positive relationships were found between three of the four cortical bone variables analysed (area, content and thickness) and SigmaPCB concentration, while no significant relationships with DDE concentration were found. None of the trabecular variables were significantly related to PCB or DDE concentration. Three of the four trabecular bone variables showed decreasing values in the beginning and increasing values at the end of period 1974-2004. No temporal trends were found for cortical bone variables. OC concentrations decreased between 1974 and 2004.

Effects of 3,3',4,4',5-pentachlorobiphenyl (PCB126) on vertebral bone mineralization and on thyroxin and vitamin D levels in Sprague-Dawley rats.

The aim of the present study is to use Fourier transform infrared spectrometry (FTIR), and transmission electron microscopy (TEM) techniques, to make a more detailed description of toxic effects of 3,3',4,4',5-pentachlorobiphenyl (PCB126) on bone tissue at the microstructural and at the molecular level as a result of an altered bone metabolism. We have analysed potential changes on vitamin D and thyroxin serum levels since these hormones represent endocrine endpoints that are critical for bone growth and development. For this purpose Sprague-Dawley rats were exposed (n=10) to PCB126 (i.p.) for 3 months (total dose, 384microg/kg bodyweight), while control rats (n=10) were injected with corn oil (vehicle). Results from FTIR showed that vertebrae from the exposed rats had an overall lower degree of mineralization (-8.5%; p<0.05) compared with the controls. In addition, results from peripheral quantitative computed tomography (pQCT) analyses showed significant increases in the trabecular bone mineral density (+12%; p<0.05) in the exposed group compared with the controls. The TEM analyses also showed an alteration in the crystallinity properties of vertebral bone mineral with a significant decrease in the size and crystallinity of apatite crystal forming the bone tissue in the exposed vs. non-exposed rats. Serum analysis revealed lower levels of thyroid hormones, FT4 (-42%; p<0.005), TT4 (-26%; p<0.005), and vitamin D (-21%; p<0.005) in exposed group compared to control animals. The complementary techniques (TEM and FTIR) used in this study have revealed insights into possible bone mineralization alteration due to PCB126 exposure. The lowering of both the thyroxin and vitamin D serum levels might be an underlying explanation for the observed effects on bone mineralization.

Exposure to pastures fertilised with sewage sludge disrupts bone tissue homeostasis in sheep.

The femurs of male and female sheep (Ovis aries), aged 18 months, bred on pastures fertilized twice annually with sewage sludge (2.25 tonnes dry matter/ha; Treated; T)) or on pastures treated with inorganic fertilizer (Control; C) were studied, using peripheral Quantitative Computed Tomography (pQCT) and the three-point bending test. Males were maintained on the respective treatments from conception to weaning and then maintained on control pastures while the females were maintained on the respective treatments until slaughter. T rams exhibited increased total bone mineral density (BMD) at the metaphyseal part of femur (+10.5%, p<0.01) compared with C rams but had a reduced total cross sectional area (CSA, -11.5%, p<0.001), trabecular CSA (-17.1%, p<0.01) and periosteal circumference (-5.7%, p<0.001). In the mid-diaphyseal part, T rams had an increased total BMD (+13.8%, p<0.0001) and stiffness (+6.4%, p<0.01) but reduced total CSA (-12.1%, p<0.0001) and marrow cavity (-25.8%, p<0.0001), relative to C rams. In ewes although pQCT analysis of neither the metaphyseal nor the mid-diaphyseal part of the female femur bones showed any significant differences with treatment, the biomechanical method revealed a reduction in load at failure (-17.3%, p<0.01) and stiffness (-10.7%, p<0.05) amongst T ewes. It is concluded that exposure to pollutants present in sewage sludge can perturb bone tissue homeostasis in sheep, but particularly in males.

Acaricidal effects of Corymbia citriodora oil containing para-menthane-3,8-diol against nymphs of Ixodes ricinus (Acari: Ixodidae).

The toxicity of para-menthane-3,8-diol (PMD), the main arthropod-repellent compound in the oil of the lemon eucalyptus, Corymbia citriodora, was evaluated against nymphs of Ixodes ricinus using five methods (A-E) of a contact toxicity bioassay. Mortality rates were estimated by recording numbers of dead nymphs at 30 min intervals during the first 5 h after the start of exposure and at longer intervals thereafter. The mortality rate increased with increasing concentration of PMD and duration of exposure with a distinct effect after 3.5 h. From the results obtained by methods A, C and E, the LC(50) range was 0.035-0.037 mg PMD/cm(2) and the LC(95) range was 0.095-0.097 mg PMD/cm(2) at 4 h of exposure; the LT(50) range was 2.1-2.8 h and the LT(95) range was 3.9-4.2 h at 0.1 mg PMD/cm(2). To determine the duration of toxic activity of PMD, different concentrations (0.002, 0.01, 0.1 mg PMD/cm(2)) were tested and mortality was recorded at each concentration after 1 h; thereafter new ticks were tested. This test revealed that the lethal activity of PMD remained for 24 h but appeared absent after 48 h. The overall results show that PMD is toxic to nymphs of I. ricinus and may be useful for tick control.

Health of herring gulls (Larus argentatus) in relation to breeding location in the early 1990s. III. Effects on the bone tissue.

Health effects associated with the Great Lakes environment were assessed in adult herring gulls (Larus argentatus) in the early 1990s, including the size and quality of their bones. Femurs were excised from 140 individuals from 10 colonies distributed throughout the Great Lakes and 2 reference colonies in Lake Winnipeg (freshwater) and the Bay of Fundy (marine). Femurs of gulls from the Great Lakes differed from the freshwater or marine reference for 9 of 12 variables of size, composition, and strength assessed using peripheral quantitative computed tomography (pQCT) and biomechanical testing. Femurs of Great Lakes gulls were significantly smaller in length (-2.9%), periosteal circumference (-2.4%), and cross-sectional area (-5.4%) than freshwater reference birds. Femurs of the Great Lakes gulls had a lower significant cortical bone mineral content (-8.1%) and density (-2%) than the marine reference. A significant increase in the amount the bone could bend before it broke (+34%) and the energy required to break it (+44%) and a significant decrease (-16.3%) in stiffness during three-point biomechanical bending test were also detected in Great Lakes versus the freshwater gulls. These differences are indicative of impaired mineralization. When divided into high and low 2,3,7,8-tetrachlorodibenzo-p-dioxin toxicity equivalent (TCDD-TEQ) colonies, the amount the bone could bend before it broke and the energy required to break it were significantly higher in the high TEQ colonies, but not high polychlorinated biphenyl (PCB) colonies. Breeding location and dietary choices of Great Lakes herring gulls in the early 1990s resulted in modulations of physiological processes that affected the size, mineralization, and biomechanical properties of bone.

Effects of short-term exposure to the DDT metabolite p,p'-DDE on bone tissue in male common frog (Rana temporaria).

Experimental studies as well as studies in free-ranging animals have shown that endocrine-disrupting chemicals (EDCs) impair bone tissue composition and strength. The aim of the present study was to expand our studies on bone tissue in a new group of animals by investigating whether bone tissue in frogs is an additional potential target of EDCs. Adult male European common frogs (Rana temporaria) were divided into 5 groups (n = 20) and injected (sc, single injection) with p,p'-DDE, a total dose of 0.01, 0.1, 1, or 10 mg of p,p'-DDE/kg body weight, respectively. A control group was treated with the vehicle (corn oil). Two weeks after injection the frogs were euthanized and samples taken. The diaphysis of the excised left femur was scanned using peripheral quantitative computed tomography (pQCT) and cortical variables, such as cortical bone mineral density (BMD), cortical cross-sectional area (CSA), and periosteal circumference, were determined. In addition, biomechanical three-point bending of the bones was conducted, with the load being applied to the same point as where the pQCT measurement was performed. The results from the pQCT measurements show that bone tissue in male frogs exposed to p,p'-DDE is negatively affected. A significant decrease in cortical BMD at the diaphysis was observed in frogs exposed to 1 mg p,p'-DDE. However, the biomechanical testing of the bones showed no significant differences between exposed and control group. Although this is the only study performed to date examining the possible relationships between EDCs and negative effects on frog bones, it supports both previous experimental findings in rodents and findings in free-ranging animals.

Effects of 17alpha-ethynylestradiol on EROD activity, spiggin and vitellogenin in three-spined stickleback (Gasterosteus aculeatus).

The three-spined stickleback (Gasterosteus aculeatus) has quantifiable biomarkers of exposure to estrogens (vitellogenin), androgens (spiggin) and aryl hydrocarbon receptor (AhR) agonists (EROD activity) and is therefore a promising test species for biomonitoring of reprotoxic chemicals in aquatic environments. In this study we evaluated the effects of 17alpha-ethynylestradiol (EE(2)) on EROD activity, induction of vitellogenin and spiggin, hepatosomatic index (HSI), ovarian somatic index (OSI) and nephrosomatic index (NSI). Adult male and female three-spined sticklebacks were exposed to concentrations of 0-170 ng EE(2)/l (measured concentrations) in a flow-through system for 21 days. Exposure to 170 ng EE(2)/l resulted in a significant 8- and 9-fold induction of gill EROD activity in males and females, respectively. In livers, EROD activity expressed in relation to microsomal protein content was suppressed due to a significant increase in microsomal protein content. Hepatic EROD activity per se expressed as picomol/min was not affected by exposure to EE(2). The lowest observed effect concentration for induction of vitellogenin in males was 53.7 ng EE(2)/l. In females, vitellogenin levels were significantly higher in those exposed to 170 ng EE(2)/l compared to controls. Spiggin production was significantly inhibited and NSI lower in males exposed to 170 ng EE(2)/l. In both females and males LSI was significantly higher in fish exposed to 170 ng EE(2)/l than in controls. In females exposed to 170 ng EE(2)/l, OSI was significantly lower and NSI higher than controls. The observed results from this study show that a synthetic estrogen can affect the well-known biomarker of exposure for dioxin-like compounds, EROD activity, and further that this response can differ between tissues. These findings are important for interpretation of biomonitoring data.

Gill EROD in monitoring of CYP1A inducers in fish: a study in rainbow trout (Oncorhynchus mykiss) caged in Stockholm and Uppsala waters.

The gill filament 7-ethoxyresorufin O-deethylase (EROD) assay was evaluated as a monitoring tool for waterborne cytochrome P4501A (CYP1A) inducers using rainbow trout (Oncorhynchus mykiss) caged in urban area waters in Sweden. To compare the CYP1A induction response in different tissues, EROD activity was also analyzed in liver and kidney microsomes. Immunohistochemistry was used to localize CYP1A protein in gill and kidney. In two separate experiments fish were caged at sites with fairly high expected polyaromatic hydrocarbon (PAH) contamination. In the first experiment, gill EROD activities were analyzed in fish exposed for 1-21 days in a river running through Uppsala. The reference site was upstream of Uppsala. In the second, gill, liver and kidney EROD activities were analyzed in fish exposed for 1-5 days in fresh or brackish waters of Stockholm and in a reference lake 60km north of Stockholm. Fish exposed for 5 days followed by 2 days of recovery in tap water in the laboratory were also examined. The gill consistently showed a higher EROD induction compared with the liver and the kidney. After 1 day of caging, gill EROD activity was markedly induced (6-17-fold) at all sites examined. Induction in gill was pronounced (5-7-fold) also in fish caged at the reference sites. In the 21-day exposure study gill EROD activity remained highly induced throughout the experiment (26-fold at most) and the induced CYP1A protein was exclusively confined to the gill secondary lamellae. In the 5-day exposure experiment, EROD activity peaked after 1 day and then declined in both gill and liver, while CYP1A immunostaining in the gill remained intense over the 5-day period. In the kidney, CYP1A staining was weak or absent. We conclude that gill EROD activity is a more sensitive biomarker of exposure to waterborne CYP1A inducers than EROD activity in liver and kidney.

Perinatal exposure to PCB 153, but not PCB 126, alters bone tissue composition in female goat offspring.

The aim of this study was to investigate if environmentally relevant doses of the putative estrogenic non dioxin-like PCB 153 and the dioxin-like PCB 126 caused changes in bone tissue in female goat offspring following perinatal exposure. Goat dams were orally dosed with PCB 153 in corn oil (98 microg/kg body wt/day) or PCB 126 (49 ng/kg body wt/day) from day 60 of gestation until delivery. The offspring were exposed to PCB in utero and through mother's milk. The suckling period lasted for 6 weeks. Offspring metacarpal bones were analysed using peripheral quantitative computed tomography (pQCT) after euthanisation at 9 months of age. The diaphyseal bone was analysed at a distance of 18% and 50% of the total bone length, and the metaphyseal bone at a distance of 9%. Also, biomechanical three-point bending of the bones was conducted, with the load being applied to the mid-diaphyseal pQCT measure point (50%). PCB 153 exposure significantly decreased the total cross-sectional area (125 mm(2)+/-4) versus non-exposed (142 mm(2)+/-5), decreased the marrow cavity (38 mm(2)+/-4) versus non-exposed (50 mm(2)+/-3) and decreased the moment of resistance (318 mm(3)+/-10) versus non-exposed (371 mm(3)+/-20) at the diaphyseal 18% measure point. At the metaphyseal measure point, the trabecular bone mineral density (121 mg/cm(3)+/-5) was increased versus non-exposed (111 mg/cm(3)+/-3). PCB 126 exposure did not produce any observable changes in bone tissue. The biomechanical testing of the bones did not show any significant changes in bone strength after PCB 153 or PCB 126 exposure. In conclusion, perinatal exposure to PCB 153, but not PCB 126, resulted in altered bone composition in female goat offspring.

Multivariate data analysis of organochlorines and brominated flame retardants in Baltic Sea guillemot (Uria aalge) egg and muscle.

Concentrations of organochlorines (OCs) and brominated flame-retardants (BFRs) were determined in guillemot (Uria aalge) eggs from the island of Stora Karlsö in the Baltic Sea where 10 eggs/year were collected in the years 2000, 2001 and 2002. The dominating contaminant in egg was p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) with a geometric mean (GM) concentration of 18200 ng/g lipid weight (lw). The GM concentration in egg of hexabromocyclododecane (HBCD) of 140 ng/glw, was significantly higher than that of polybrominated diphenyl ether (summation operatorPBDE) of 77 ng/glw. For the evaluation of the data multivariate data analysis techniques namely principal components analysis (PCA), partial least squares regression (PLS), soft independent modelling of class analogy (SIMCA classification), and PLS discriminant analysis (PLS-DA), were used. We investigated whether the eggs' biological characteristics co-varied with egg concentrations of OCs and BFRs, and found e.g., significant negative correlations between egg weight and concentrations of HCB and p,p'-DDE. A PLS model with analyzed BFRs as the Y matrix and OCs as the X matrix could, with varying accuracy, calculate the concentrations of BFRs in the individual egg from their concentrations of OCs (e.g., R(2)Y of 0.89 for BDE47, and of 0.50 for HBCD). Lastly, we compared the contaminant concentrations in the eggs to those in previously analyzed pectoral muscles from adult guillemots from Stora Karlsö, from the year 2000. A PLS-DA model, showed that some of the contaminants (e.g., HBCD and CB28) had significantly higher concentrations in egg than in muscle, although 7 of the 14 contaminants showed no difference in concentrations between the two matrices.

Abnormal bone composition in female juvenile American alligators from a pesticide-polluted lake (Lake Apopka, Florida).

Reproductive disorders have been found in pesticide-exposed alligators living in Lake Apopka, Florida (USA). These disorders have been hypothesized to be caused by exposure to endocrine- disruptive estrogen-like contaminants. The aim of this study was to expand our analysis beyond previous studies by investigating whether bone tissue, known to be affected by sex steroid hormones, is a potential target of endocrine disruptors. Long bones from 16 juvenile female alligators from Lake Apopka (pesticide-contaminated lake) and Lake Woodruff (control lake) were evaluated by peripheral quantitative computed tomography. We observed significant differences in bone composition, with female alligators from the contaminated lake having greater trabecular bone mineral density (BMD), total BMD, and trabecular mineral content compared with females from the control lake (p < 0.05). Increased trabecular and total BMD measurements suggest that juvenile female alligators from Lake Apopka were exposed to contaminants that created an internal environment more estrogenic than that normally observed. This estrogenic environment could be caused by both natural and anthropogenic compounds. Effects on BMD indicate interference with bone homeostasis. We hypothesize that contaminants present in the lake inhibit the natural and continuous resorption of bone tissue, resulting in increased bone mass. Although this is the only study performed to date examining effects of environmental estrogenic compounds on alligator bones, it supports previous laboratory-based studies in rodents. Further, this study is important in demonstrating that the alterations in morphology and physiology induced in free-ranging individuals living in environments contaminated with endocrine-active compounds are not limited to a few systems or tissues; rather, effects can be observed in many tissues affected by these hormones.

Estrogen supplementation modulates effects of the endocrine disrupting pollutant PCB126 in rat bone and uterus: diverging effects in ovariectomized and intact animals.

The aims of the present study are to compare effects of estrogen depletion (OVX) and estradiol (E2) supplementation on the tissue effects of exposure to the endocrine disrupting organochlorine 3,3',4,4',5-pentachlorobiphenyl (PCB126). For this purpose two highly estrogen-dependent tissues, bone and uterus, were studied. Forty rats exposed to PCB126 (ip) for 3 months (total dose 384 microg/kg body weight (bw)) were randomized in to OVX/sham operation or E2 supplementation (ip, 23 microg/kg, 3 days weekly) per vehicle (corn oil) groups in a 2 x 2 factorial design. Sham operated rats were treated with vehicle, PCB or PCB plus E2 (sham, sham + PCB and sham + PCB + E2, n=10 per group) whereas ovariectomized were treated with vehicle, PCB or PCB plus E2(OVX, OVX + PCB and OVX + PCB + E2, n=10 per group). As control groups served OVX or sham, and OVX + E2 (n=10 in each group). In OVX rats PCB126 + E2 treatment increased trabecular bone volume (TBV) (P<0.01), whilst the opposite was found in sham-operated rats (P<0.01). In OVX animals exposed to PCB126, E2 supplementation decreased the uterine weight and increased the uterine ERbeta mRNA level, whilst no difference was found between the PCB126 and PCB126 + E2 exposed groups in the sham-operated animals. In conclusion, estrogen modulates PCB126 induced effects on trabecular bone, as well as several uterine parameters. These results further support an important role of estrogen on the toxic effects of PCB126 on bone and uterus.

The dioxin-like pollutant PCB 126 (3,3',4,4',5-pentachlorobiphenyl) affects risk factors for cardiovascular disease in female rats.

Epidemiological studies suggest that exposure to persistent organic pollutants such as organochlorines might induce cardiovascular disorders and diabetes. Some of these organochlorines, such as dioxins and some dioxin-like PCBs, have been characterised as anti-estrogenic due to their inhibition of estrogenic-induced responses. In the present pilot study, 40 female rats were subjected to either exposure to the dioxin-like 3,3',4,4',5-pentachlorobiphenyl (PCB 126) or vehicle, as well as ovariectomy (OVX) or sham operation in a 2 x 2 factorial design over 12 weeks to explore potential interactions between estrogen status and PCB 126 exposure on cardiovascular risk factors. PCB 126 increased heart weight and serum cholesterol levels in both groups. PCB 126 increased blood pressure in the sham-operated animals only. In conclusion, PCB 126 exposure in female rats resulted in effects on cardiovascular risk factors, such as serum cholesterol, blood pressure, and heart weight. Of these effects of PCB 126, the increase in blood pressure was dependent on estrogen status.

Bone mineral density in male Baltic grey seal (Halichoerus grypus).

Bone mineral density (mg cm(-3)) was studied in male Baltic grey seals (4-23 years of age) by noninvasive computed tomography (pQCT). The material was grouped according to year of collection. Group A: 1850-1955, a period before the main introduction of organochlorines (OCs); Group B: 1965-1985, a period with very high OC contamination; and Group C: 1986-1997, a period with decreasing concentrations of OCs. The reproducibility of the measurements was good with a Coefficient of Variation (CV) ranging from 0.1% to 2.1%. Trabecular bone mineral density of the radius was significantly higher in specimens collected 1986-1997 than in those collected 1965-1985 (p < 0.05). Cortical bone mineral density of the mandible was significantly lower in specimens collected 1986-1997 compared with those collected 1850-1955 (p < 0.05). These results indicate different responses over time in trabecular and cortical bone. During the period of very high OC contamination (1965-1985), trabecular bone density was lowest, whereas cortical bone density was lowest in specimens collected 1985-1997, representing a period of fairly low OC contamination. The mechanisms behind these effects are not known. However, it can be assumed that OCs are involved. Information about residue levels of OCs in the studied individuals is lacking and, therefore, it was not possible to evaluate the impact of OCs in this respect.

Bisphenol A is related to circulating levels of adiponectin, leptin and ghrelin, but not to fat mass or fat distribution in humans.

OBJECTIVE: Since bisphenol A (BPA) has been shown to induce obesity in experimental studies, we explored the associations between BPA and fat mass, fat distribution and circulating levels of adiponectin, leptin and ghrelin in humans. METHODS: In the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS), fat mass and fat distribution were determined in 70-year-old men and women (n=890) by dual-energy X-ray absorptiometry (DXA) and magnetic resonance imaging (MRI) (n=287). Serum levels of BPA were analyzed using isotope liquid chromatography/tandem mass spectrometer (API4000LC-MS/MS). Hormone levels were analyzed with radioimmunoassays (RIA) or enzyme-linked immunosorbent assay (ELISA). Imaging was performed approximately two years following collection of other data. RESULTS: Serum concentrations of BPA were not related to adipose tissue measurements by DXA or MRI. BPA associated positively with adiponectin and leptin, but negatively with ghrelin, following adjustments for sex, height, fat mass, lean mass, smoking, alcohol consumption, physical activity, energy intake, and educational levels (p<0.001, p=0.009, p<0.001, respectively). The relationship between BPA and ghrelin was stronger in women than in men. CONCLUSION: Although no relationships between BPA levels and measures of fat mass were seen, BPA associated strongly with the adipokines adiponectin and leptin and with the gut-hormone ghrelin suggesting that BPA may interfere with hormonal control of hunger and satiety.

Bisphenol A exposure increases liver fat in juvenile fructose-fed Fischer 344 rats.

BACKGROUND: Prenatal exposure to bisphenol A (BPA) has been shown to induce obesity in rodents. To evaluate if exposure also later in life could induce obesity or liver damage we investigated these hypothesises in an experimental rat model. METHODS: From five to fifteen weeks of age, female Fischer 344 rats were exposed to BPA via drinking water (0.025, 0.25 or 2.5 mg BPA/L) containing 5% fructose. Two control groups were given either water or 5% fructose solution. Individual weight of the rats was determined once a week. At termination magnetic resonance imaging was used to assess adipose tissue amount and distribution, and liver fat content. After sacrifice the left perirenal fat pad and the liver were dissected and weighed. Apolipoprotein A-I in plasma was analyzed by western blot. RESULTS: No significant effects on body weight or the weight of the dissected fad pad were seen in rats exposed to BPA, and MRI showed no differences in total or visceral adipose tissue volumes between the groups. However, MRI showed that liver fat content was significantly higher in BPA-exposed rats than in fructose controls (p=0.04). BPA exposure also increased the apolipoprotein A-I levels in plasma (p<0.0001). CONCLUSION: We found no evidence that BPA exposure affects fat mass in juvenile fructose-fed rats. However, the finding that BPA in combination with fructose induced fat infiltration in the liver at dosages close to the current tolerable daily intake (TDI) might be of concern given the widespread use of this compound in our environment.

Quantification of total and visceral adipose tissue in fructose-fed rats using water-fat separated single echo MRI.

OBJECTIVE: The aim of this study was to setup a rodent model for modest weight gain and an MRI-based quantification of body composition on a clinical 1.5 T MRI system for studies of obesity and environmental factors and their possible association. DESIGN AND METHODS: Twenty-four 4-week-old female Fischer rats were divided into two groups: one exposed group (n = 12) and one control group (n = 12). The exposed group was given drinking water containing fructose (5% for 7 weeks, then 20% for 3 weeks). The control group was given tap water. Before sacrifice, whole body MRI was performed to determine volumes of total and visceral adipose tissue and lean tissue. MRI was performed using a clinical 1.5 T system and a chemical shift based technique for separation of water and fat signal from a rapid single echo acquisition. Fat signal fraction was used to separate adipose and lean tissue. Visceral adipose tissue volume was quantified using semiautomated segmentation. After sacrifice, a perirenal fat pad and the liver were dissected and weighed. Plasma proteins were analyzed by Western blot. RESULTS: The weight gain was 5.2% greater in rats exposed to fructose than in controls (P = 0.042). Total and visceral adipose tissue volumes were 5.2 cm3 (P = 0.017) and 3.1 cm3 (P = 0.019) greater, respectively, while lean tissue volumes did not differ. The level of triglycerides and apolipoprotein A-I was higher (P = 0.034, P = 0.005, respectively) in fructose-exposed rats. CONCLUSIONS: The setup induced and assessed a modest visceral obesity and hypertriglyceridemia, making it suitable for further studies of a possible association between environmental factors and obesity.

Impact of humic substances on EROD activity in gill and liver of three-spined sticklebacks (Gasterosteus aculeatus).

Humic substances (HS) are ubiquitous in the environment and have been found to influence physiological functions of aquatic organisms. In the present study, three-spined sticklebacks (Gasterosteus aculeatus) were exposed to HS of different origins to evaluate effects on the 7-ethoxyresorufin O-deethylase (EROD) activity catalyzed by cytochrome P4501A (CYP1A) in the liver and the gill. To that end, three-spined sticklebacks were exposed for 48 h to different concentrations of synthetic humic acid (AHA), Nordic reservoir natural organic matter (N.R.-NOM) and water from six lakes with different concentrations of HS. EROD activity was significantly induced (3-6-fold) in the gills of fish exposed to water from all lakes except the lake with the lowest concentration of HS. All tested concentrations of AHA and N.R.-NOM significantly induced gill EROD activity and the induction was dose-dependent. AHA, but neither N.R.-NOM nor lake water, induced EROD activity in the liver. In addition, fish were exposed to the potent CYP1A inducers benzo(a)pyrene (BaP) and PCB126 in combination with AHA. Presence of AHA had no significant effect on EROD induction by BaP or PCB126. The components in HS responsible for EROD induction remain to be identified. Our finding that HS of both natural and synthetic origin induce EROD activity in the gill is of significance for the interpretation of biomonitoring data on EROD activity as well as for the choice of suitable reference waters.