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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Exposure of Caco-2 cells to PFOS and PFOA

Neskovic, Anika January 2007 (has links)
<p>The toxicity of perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) was measured. When Caco-2 cells from human adenocarcinoma are cultivated on a filter a monolayer is formed with properties similar to human duodenum epithelium. The Caco-2 cells grown on filter were exposed to the environmental contaminants PFOS and PFOA. The effects on the Caco-2 epithelium were examined by four different methods: trans-epithelial resistance (TEER), leakage of the intracellular protein lactate dehydrogenase (LDH), 14C-mannitol passage through the epithelium and protein content of the epithelium. TEER and C-mannitol passage show the Caco-2 cellmonolayer integrity, LDH leakage gives information of cytotoxicity and protein content of the epithelium shows cell adhension to the filter.</p><p>In the first study TEER decreased at the highest concentrations of PFOS and PFOA (1Mm). The 14C-mannitol passage increased at the highest PFOS concentration. No cytotoxicity was shown and protein-loss was not observed. The second study with PFOS doses of 0, 1, 10, 100 and 500µM and 1 and 10mM showed that the effect of PFOS on TEER was dose-dependent. The 14C-mannitol passage was very high at the highest PFOS-concentration (10mM) and a dose-response was indicated. No cytotoxicity was demonstrated and protein-quantity was not affected. In the third study it was demonstrated that the toxicity of PFOS did not depend on the different concentrations of the oil-emulsion used to dissolve PFOS and PFOA.</p>
2

Exposure of Caco-2 cells to PFOS and PFOA

Neskovic, Anika January 2007 (has links)
The toxicity of perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) was measured. When Caco-2 cells from human adenocarcinoma are cultivated on a filter a monolayer is formed with properties similar to human duodenum epithelium. The Caco-2 cells grown on filter were exposed to the environmental contaminants PFOS and PFOA. The effects on the Caco-2 epithelium were examined by four different methods: trans-epithelial resistance (TEER), leakage of the intracellular protein lactate dehydrogenase (LDH), 14C-mannitol passage through the epithelium and protein content of the epithelium. TEER and C-mannitol passage show the Caco-2 cellmonolayer integrity, LDH leakage gives information of cytotoxicity and protein content of the epithelium shows cell adhension to the filter. In the first study TEER decreased at the highest concentrations of PFOS and PFOA (1Mm). The 14C-mannitol passage increased at the highest PFOS concentration. No cytotoxicity was shown and protein-loss was not observed. The second study with PFOS doses of 0, 1, 10, 100 and 500µM and 1 and 10mM showed that the effect of PFOS on TEER was dose-dependent. The 14C-mannitol passage was very high at the highest PFOS-concentration (10mM) and a dose-response was indicated. No cytotoxicity was demonstrated and protein-quantity was not affected. In the third study it was demonstrated that the toxicity of PFOS did not depend on the different concentrations of the oil-emulsion used to dissolve PFOS and PFOA.
3

Prenatal Exposure to Perfluoroalkyl Acids and Serum Testosterone Concentrations at 15 Years of Age in Female ALSPAC Study Participants

Maisonet, Mildred, Calafat, Antonia M., Marcus, Michele, Jaakkola, Jouni J.K., Lashen, Hany 01 December 2015 (has links)
Background: Exposure to perfluorooctane sulfonic acid (PFOS) or to perfluorooctanoic acid (PFOA) increases mouse and human peroxisome proliferator–activated receptor alpha (PPARα) subtype activity, which influences lipid metabolism. Because cholesterol is the substrate from which testosterone is synthesized, exposure to these substances has the potential to alter testosterone concentrations. Objectives: We explored associations of total testosterone and sex hormone–binding globulin (SHBG) concentrations at age 15 years with prenatal exposures to PFOS, PFOA, perfluorohexane sulfonic acid (PFHxS), and perfluoronanoic acid (PFNA) in females. Methods: Prenatal concentrations of the perfluoroalkyl acids (PFAAs) were measured in serum collected from pregnant mothers at enrollment (1991–1992) in the Avon Longitudinal Study of Parents and Children (ALSPAC). The median gestational age when the maternal blood sample was obtained was 16 weeks (interquartile range, 11–28 weeks). Total testosterone and SHBG concentrations were measured in serum obtained from their daughters at 15 years of age. Associations between prenatal PFAAs concentrations and reproductive outcomes were estimated using linear regression models (n = 72). Results: Adjusted total testosterone concentrations were on average 0.18-nmol/L (95% CI: 0.01, 0.35) higher in daughters with prenatal PFOS in the upper concentration tertile compared with daughters with prenatal PFOS in the lower tertile. Adjusted total testosterone concentrations were also higher in daughters with prenatal concentrations of PFOA (β = 0.24; 95% CI: 0.05, 0.43) and PFHxS (β = 0.18; 95% CI: 0.00, 0.35) in the upper tertile compared with daughters with concentrations in the lower tertile. We did not find evidence of associations between PFNA and total testosterone or between any of the PFAAs and SHBG. Conclusions: Our findings were based on a small study sample and should be interpreted with caution. However, they suggest that prenatal exposure to some PFAAs may alter testosterone concentrations in females.

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