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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

Neonatal Exposure To Bisphenol Analogues Disrupts Reproductive Organ Development Of Male Mice

Widelka, Malgorzata 01 December 2016 (has links)
Bisphenol A (BPA) is one of the highest volume chemicals produced worldwide and, as a result, is universally found in environmental and human matrixes. Bisphenol A is a known endocrine disruptor that acts as an estrogen agonist and an androgen antagonist. Due to health concerns, BPA is being phased out and replaced by other bisphenol analogues structurally similar to BPA. To date, there have been little to no studies showing the effects of BP analogues on the reproductive organ development of male mice. Thus, this study aimed to compare the effects of BPA and selected analogues (including BPB, BPE, and BPS) on the reproductive organ development in male mice, and determine preliminary toxicity threshold levels, such as the lowest-observed-effect-dose (LOED) and no-observed-effect-dose (NOED). Exposure to BPA, BPB and BPE via subcutaneous injection at a dose of 10 μg/g body weight (bw)/day each significantly caused a decrease in anogenital distance and glans penis length in male mice. Testis weight was also significantly reduced by BPA and BPE. Although BPS did not cause an effect on the glans penis length, anogenital distance or testis weight, histology work indicated that the spines on the glans penis were at a different developmental stage than the control. A similar result was seen with BPA on the glans penis spines. The LOED and NOED of BPA affecting anogenital distance, penis length, or testis weight were determined to be 10 and 5 μg/g bw/day, respectively. These LOED and NOED values are preliminary for BPA, because only five dose levels are used. Further research is needed to estimate more accurate threshold levels for the studied endpoints for BPA as well as other bisphenol analogues. The results indicated that some bisphenol analogues (BPB and BPE) showed comparable effects to BPA on the reproductive organ development of male mice, including anogenital distance and penis length. This could be indicative of more severe reproductive issues later in life and raised a concern on the safety of using these analogues to replace BPA in consumer products. More research is needed to investigate the mechanisms of the observed effects on genetic or molecular levels, determine what the long-term adverse effects of bisphenol analogues are to the reproductive system of male mice, and determine whether similar effects will be seen at dose levels comparable to human exposure rates.
2

Biodegradation of bisphenol a and ibuprofen by ammonia oxidizing bacteria

Subramanya, Nethra T. 17 September 2007 (has links)
Bisphenol A (BPA) is a compound that is commonly used in the manufacture of epoxy resins and plastics. Because of large scale production and widespread usages, BPA is released into the atmosphere through air, land, and water. BPA is weakly estrogenic in animals and has acute aquatic toxicity even at low concentrations of 1- 10μg/L. Ibuprofen is a widely used analgesic and antipyretic. Ibuprofen and its metabolites are mainly released into the environment by human urinary excretion. Ibuprofen has been detected at low concentrations in surface and waste waters. The environmental and health effects at such concentrations are unclear. The high removal of BPA and ibuprofen in the wastewater treatment plants (WWTPs), suggest that biodegradation might be responsible for the removal of these compounds. Several bacterial strains, isolated from waste water, are known to degrade BPA and ibuprofen. No studies, however, have reported using ammonia oxidizing bacteria for this purpose. Ammonia oxidizing bacteria (AOB) are an important group of microorganisms in nitrifying activated sludge of WWTPs. AOB are known to express ammonia monooxygenase (AMO) to degrade many different aromatic and aliphatic organics via cometobolic degradation (non beneficial mechanism). Nitrosomonas europaea is a widely studied AOB found to degrade synthetic estrogen by a study. This study aims to characterize the biodegradation of BPA and ibuprofen by AOB. The biodegradation ability of N.europaea with respect to BPA and ibuprofen was examined. Experiments were conducted in the presence/absence of the AMO inhibitor (allylthiourea), an external reducing energy source (sodium formate) and different primary substrate (ammonia) concentrations. The second part of the study comprises of biodegradation tests on BPA and ibuprofen using activated sludge from two WWTPs, one with one-sludge activated sludge system and the other one with two-sludge nitrification system. From the experiments conducted BPA at a concentration of 1.6 mg/L was degraded to 0.12 mg/L by N.europaea. BPA at concentrations of 1.0 mg/L and 0.75 mg/L was completely degraded by the cells. Resting cells of N.europaea were, however, unable to degrade BPA. Also ibuprofen of two concentrations, 0.42 mg/L and 0.8 mg/L, were not degraded by the culture. BPA at a concentration of 1 mg/L was degraded to 0.2 mg/L and ibuprofen at 0.5 mg/L was completely degraded by the activated sludge from the combined reactor. The activated sludge from the nitrification tank degraded BPA of concentration 1 mg/L and ibuprofen of concentration 0.5 mg/L completely. Hence, it can be summarized that Bisphenol A was degraded by N.europaea and also by the activated sludge obtained from the WWTPs. Ibuprofen was found incapable of inhibiting ammonia oxidizing bacteria in the case of the pure culture while it was successfully degraded by the mixed culture.
3

Verhalten der endokrin wirksamen Substanz Bisphenol A bei der kommunalen Abwasserentsorgung /

Gehring, Martin. January 2004 (has links)
Zugl.: Dresden, Techn. Universiẗat, Diss., 2004.
4

EFFECTS OF BISPHENOL A ANALOGUES (BISPHENOL E AND BISPHENOL S) ON REPRODUCTIVE FUNCTION IN MICE

Shi, Mingxin 01 August 2019 (has links)
Bisphenol (BP) A is a common manufacturing chemical in polycarbonate plastics and has been widely used in plastics, epoxy resin liners of canned foods, dental materials, and thermal receipts. Human exposure to BPA is associated with a negative impact on human health including the development and function of the reproductive system due to its action as an endocrine-disrupting chemical (EDC). Numerous experimental studies have demonstrated that BPA impairs both male and female reproductive function, despite the variation in study paradigms such as dose, exposure route, timing, and outcomes measured. Due to the toxicological effects of BPA, BPA analogues such as BPS have been used as alternatives for BPA. However, recent evidence has suggested these BPA analogues can induce similar or even more severe toxic effects as BPA, and health risks of exposure to replacement bisphenols need to be considered. Therefore, my study was designed to examine whether prenatal exposure to BPE and BPS negatively impacts on male and female reproductive function in mice. Pregnant females were orally administrated corn oil (control), BPA, BPE, and BPS (0.5, 20, or 50mg/kg/day) from gestational day 11 (the presence of vaginal plug=1) to birth, and reproductive tissues in F1 mice were collected and analyzed in both neonatal and adult mice. In males, I observed reduced sperm counts and quality, disrupted stages of spermatogenesis in adults and increased germ cell apoptosis in neonatal testis following prenatal BPA, BPE or BPS exposure. Particularly, I found the expression of methyltransferases for DNA methylation and histone modification was also affected by prenatal exposure to BPA, BPE, or BPS in neonatal testis, suggesting a potential of epigenetic alterations in F1 males. In females, prenatal exposure to BPE and BPS accelerated the onset of puberty, disrupted estrous cyclicity, and caused several fertility problems especially in aged mice. In the neonatal ovaries, I also observed that BPE and BPS inhibit germ cell nest breakdown comparable to BPA. These results suggest that prenatal exposure to BPE and BPS with physiologically relevant doses affects male and female reproductive function probably due to germ cell development defects in the developing gonads. Finally, to understand their complete impact on male and female fertility, a study of transgenerational effects of BPE and BPS is performed to examine the transgenerational effects of prenatal exposure to BPA, BPE and BPS on reproductive function in F3 offspring. To be called transgenerational, expression of the specific phenotype will be continued at least across three generations. As described in previous studies, the direct exposure of a pregnant female (F0 generation) results in the exposure of the embryos (F1 generation) and the germline that will generate the next generation (F2 generation). Thus, I orally exposed to control treatment (corn oil), BPA, BPE or BPS (0.5 or 50 μg/kg/day) from gestational day 7 to birth in pregnant females (F0). Mice from F1 and F2 offspring were used to generate the F3 generation. In F3 males, prenatal exposure to BPA, BPE, and BPS induces persistence and even more severe phenotypes in sperm counts and motility in the F3 generation than in the F1 offspring. The expression of DNA and histone methyltransferases were transgenerationally increased by BPA, BPE and BPS exposure in both neonatal and adult testis. In F3 females, prenatal exposure to BPA, BPE, and BPS accelerated the onset of puberty and exhibited abnormal estrous cyclicity, and those females exhibited similar fertility problems as those in the F1 generation. However, BPA, BPE and BPS exposure did not affect neonatal follicular development such as germ cell nest breakdown or follicle numbers in the ovary on postnatal day 4. Taken together, our results suggest that prenatal exposure to BPA analogues, BPE and BPS, have transgenerational effects on male and female reproductive function in mice. Our findings suggest the hypothesis that transgenerational epigenetic alterations in germ cells may lead to reproductive disorders/dysfunction in the F3 generation.
5

In Vitro Effects of Bisphenol A on Prostate Cells: Searching for Clues of Environmental Carcinogenesis

Sienkiewicz, Marta 30 April 2012 (has links)
Estrogens maintain the appropriate androgen-estrogen balance for normal regulation of the structure and function of the male reproductive tract, including the prostate gland. This research investigated viability of cells and expression of selected genes in prostate carcinoma cells (PC-3) exposed to bisphenol A (BPA), an estrogen-like substance present in a number of plastic materials. PC-3 cells are able to metabolize BPA at concentrations below 100 µM. BPA exposure at concentrations between 1nM and 100 µM does not increase or significantly reduce cell viability of these cells. Although the genes investigated in this study (GSTP1 and MGMT) did not show a significant change in expression following in vitro exposure to BPA, the positive control ethinyl estradiol (EE2) caused an increase in GSTP1 expression at mRNA level. These results indicate that BPA does not affect the viability of prostate cells, and motivate a need for further research to identify other genes that could be affected by BPA.
6

In Vitro Effects of Bisphenol A on Prostate Cells: Searching for Clues of Environmental Carcinogenesis

Sienkiewicz, Marta 30 April 2012 (has links)
Estrogens maintain the appropriate androgen-estrogen balance for normal regulation of the structure and function of the male reproductive tract, including the prostate gland. This research investigated viability of cells and expression of selected genes in prostate carcinoma cells (PC-3) exposed to bisphenol A (BPA), an estrogen-like substance present in a number of plastic materials. PC-3 cells are able to metabolize BPA at concentrations below 100 µM. BPA exposure at concentrations between 1nM and 100 µM does not increase or significantly reduce cell viability of these cells. Although the genes investigated in this study (GSTP1 and MGMT) did not show a significant change in expression following in vitro exposure to BPA, the positive control ethinyl estradiol (EE2) caused an increase in GSTP1 expression at mRNA level. These results indicate that BPA does not affect the viability of prostate cells, and motivate a need for further research to identify other genes that could be affected by BPA.
7

Charakterisierung des Abbaus von Bisphenol A durch Cupriavidus basilensis und Bewertung der cytotoxischen Wirkung dieses Schadstoffs anhand von Membranlipidanalysen in Pseudomonas putida /

Fischer, Janett. January 1900 (has links)
Zugl.: Greifswald, Universiẗat, Diss., 2009.
8

Effects of short-term and long-term administration of bisphenol A on sex behavior, body weight, and uterine weight in adult female ovariectomized rats /

Merrill, Liana. January 2009 (has links)
Thesis -- Departmental honors in Psychobiology. / Spine title: Effects of bisphenol A on adult female ovariectomized rats. Bibliography: ℓ. 46-55.
9

Toxins in Renal Disease and Dialysis Therapy : Genotoxic Potential and Mechanisms

Fink, Kristin January 2008 (has links)
Würzburg, Univ., Diss., 2008 / Zsfassung in dt. Sprache
10

In Vitro Effects of Bisphenol A on Prostate Cells: Searching for Clues of Environmental Carcinogenesis

Sienkiewicz, Marta January 2012 (has links)
Estrogens maintain the appropriate androgen-estrogen balance for normal regulation of the structure and function of the male reproductive tract, including the prostate gland. This research investigated viability of cells and expression of selected genes in prostate carcinoma cells (PC-3) exposed to bisphenol A (BPA), an estrogen-like substance present in a number of plastic materials. PC-3 cells are able to metabolize BPA at concentrations below 100 µM. BPA exposure at concentrations between 1nM and 100 µM does not increase or significantly reduce cell viability of these cells. Although the genes investigated in this study (GSTP1 and MGMT) did not show a significant change in expression following in vitro exposure to BPA, the positive control ethinyl estradiol (EE2) caused an increase in GSTP1 expression at mRNA level. These results indicate that BPA does not affect the viability of prostate cells, and motivate a need for further research to identify other genes that could be affected by BPA.

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