Dragana Vasiljevic Tomic - Academia.edu (original) (raw)

Papers by Dragana Vasiljevic Tomic

This paper is based on the analysis of several international conventions and rules, as well as na... more This paper is based on the analysis of several international conventions and rules, as well as national regulations dealing with protection of rights of all members of community, especially preventing all potential forms of discrimination and with special focus on people with disabilities. Application of the European accessibility concept [i] would achieve the promotion of a new social model that would completely transform the relation towards the persons with disabilities. The concept suggests essentially different approach – treating the community as a whole, and thus all its needs and needs of each community member as one, making no difference among individual groups within the overall population, but provides the solutions that meet the conditions to fulfil the need of each individual member and the community as a whole. Terms: accessibility, access to all, inclusion, inclusive design, universal design, values/directions, principles, standards/norms/technical regulations, legisl...

On Architecture, international conference and exhibition, STRAND, 2013

This paper examines the potential resources in the educational process and research methodology i... more This paper examines the potential resources in the educational process and research methodology in the field of architectural and urban design, by positioning of the Blog as a formal framework of content and representation of contemporary architecture and as a tool that can contribute to the growing complexity of the knowledge base in the field of architecture. In this context, this paper examines two theses. The first one suggests that, used properly, a Blog can become a useful tool in the form and content of the research. This is based on the assumption that reflection of the architectural design process may have a significant influence on the development of architectural education, particularly in the area of information exchange and raising of the critical awareness about the problems of the specific topics in spatial, contextual and formal sense. The second theses encourages the development of blogs as a tool that may extend the interpretive potential of the representation in the field of architectural and urban design, by displacing it from the real to the virtual space and by giving it a value of the driver and initiator of possible changes. The paper also examines the ways in which the blog can establish, enhance, deepen or direct the already known and reliable methodological and conceptual basis of architectural education on the one side and representation of architectural and urban design, on the other side.

The application of colour in the architectural composition represents an effective instrument tha... more The application of colour in the architectural composition represents an effective instrument that can achieve a number of effects. Knowledge of its impact is a powerful tool in the hands of every architect. Warm and cool tones, by their nature, can cause various effects of depth, emphasis and suppression of certain elements to some extent. Colours can create the illusion of area increase and decrease and cause a number of other effects. The aim of this paper is focused on solid colour (monochromatic) architecture, with special reference to the usage of white colour. The colour is the most effective tool of distinguishing and perception. All of the visual appearance owes its existence to light and colour. The world of colour is not one source of countless tones, but is clearly designed on the basis of three primary colours and their combinations. Special mental attitude is required for a person to organize his world of colour in accordance with perceptual characteristics. Colour nam...

Facta Universitatis - Series: Architecture and Civil Engineering, 2020

Past urban planning practices for embassy buildings have largely been indifferent to environments... more Past urban planning practices for embassy buildings have largely been indifferent to environments and the context of cities, oftentimes causing negative effects on the urban matrix. Implementing a more open, transparent building process for its diplomatic outposts overseas, Japan has managed to contribute to overall city development, quality of its public spaces and the image it holds in host countries. These processes will be examined and findings elaborated for the new Japanese embassy in Belgrade, Serbia, how utilizing such methodology presents an improvement, in engineering and urban planning terms, as well as a new method of cultural sustainability.

Facta universitatis - series: Architecture and Civil Engineering, 2017

The aim of this paper is research of the potential and redefining of space of the contemporary ur... more The aim of this paper is research of the potential and redefining of space of the contemporary urban context, by recognizing movement and senses as principles of accessibility and affirmation of the neglected values of the city in regard to design aspects. A global context of networking transforms a modern city into processes of busy lifestyle, which neglect diversity and senses. Flows and networking, as the carriers of this context, despite their goal to create a connection between the global and the local and establish equality of all users, generate local separation and segregation, eliminating specific local traits and individual needs, thus neglecting individual units of space, social groups and subjects. The consequences of the city developing in this way are spatial fragments not connected to a network and not defined, and on the other hand neglected in a way that leads to specific environmental and sensory values, which under contemporary conditions propagate subjectivity, d...

Reproductive Toxicology, May 31, 2007

Reprod Toxicol, 2007

Recently, we generated transgenic mice in which ERα can be inducibly overexpressed in reproductiv... more Recently, we generated transgenic mice in which ERα can be inducibly overexpressed in reproductive tissues (ERα overexpressors). These mice were used to test the hypothesis that prenatal and postnatal ERα overexpression reduces female fertility. To do so, litter sizes, ovulation, follicle numbers, uterine histology, implantation sites, and hormone levels were compared in ERα overexpressors and controls. The data indicate that ERα overexpressors have reduced fertility compared to controls and that the reduced fertility is not due to reduced ovulatory capacity, altered levels of estradiol, FSH, and LH, or impaired follicular growth. ERα overexpressors, however, had a higher number of apoptotic cells in the endometrial epithelium and a reduced number of implantation sites compared to controls. Thus, the increased number of apoptotic cells and reduced number of implantation sites observed in ERα overexpressing uteri compared to controls may, in part, account for the reduced litter size produced by ERα overexpressing females.

Molecular Endocrinology, Jul 2, 2013

Smad3 is an important mediator of the TGF beta signaling pathway. Interestingly, Smad3-deficient ... more Smad3 is an important mediator of the TGF beta signaling pathway. Interestingly, Smad3-deficient (Smad3-/-) mice have reduced fertility compared with wild-type (WT) mice. To better understand the molecular mechanisms underlying the reduced fertility in Smad3-/- animals, this work tested the hypothesis that Smad3 deficiency interferes with three critical aspects of folliculogenesis: growth, atresia, and differentiation. Growth was assessed by comparing the size of follicles, expression of proliferating cell nuclear antigen, and expression of cell cycle genes in Smad3-/- and WT mice. Atresia was assessed by comparing the incidence of atresia and expression of bcl-2 genes involved in cell death and cell survival in Smad3-/- and WT mice. Differentiation was assessed by comparing the expression of FSH receptor (FSHR), estrogen receptor (ER) alpha, ER beta, and inhibin alpha-, beta(A)-, and beta(B)-subunits in Smad3-/- and WT mice. Because growth, atresia, and differentiation are regulated by hormones, estradiol, FSH, and LH levels were compared in Smad3-/- and WT mice. Moreover, because alterations in folliculogenesis can affect the ability of mice to ovulate, the number of corpora lutea and ovulated eggs in response to gonadotropin treatments were compared in Smad3-/- and WT animals. The results indicate that Smad3 deficiency slows follicle growth, which is characterized by small follicle diameters, low levels of proliferating cell nuclear antigen, and low expression of cell cycle genes (cyclin-dependent kinase 4 and cyclin D2). Smad3 deficiency also causes atretic follicles, degenerated oocytes, and low expression of bcl-2. Furthermore, Smad3 deficiency affects follicular differentiation as evidenced by decreased expression of ER beta, increased expression of ER alpha, and decreased expression of inhibin alpha-subunits. Smad3 deficiency causes low estradiol and high FSH levels. Finally, Smad3-/- ovaries have no corpora lutea, and they do not ovulate after ovulatory induction with exogenous gonadotropins. Collectively, these data provide the first evidence that reduced fertility in Smad3-/- mice is due to impaired folliculogenesis, associated with altered expression of genes that control cell cycle progression, cell survival, and cell differentiation. The findings that Smad3-/- follicles have impaired growth, increased atresia, and altered differentiation in the presence of high FSH levels, normal expression of FSHR, and lower expression of cyclin D2, suggest a possible interaction between Smad3 and FSH signaling downstream of FSHR in the mouse ovary.

Toxicol Sci, 2006

Methoxychlor (MXC) is a pesticide that is known to bind to estrogen receptor alpha (ERa) and to i... more Methoxychlor (MXC) is a pesticide that is known to bind to estrogen receptor alpha (ERa) and to induce atresia of antral ovarian follicles. Although studies have shown that MXC is toxic to the ovary, we hypothesize that perturbation to the estrogensignaling system (i.e., increase or decrease in estrogen sensitivity) might alter ovarian responsiveness to MXC. Thus, we examined whether ERa overexpression alters the ability of MXC to increase follicle atresia. To do so, we employed a transgenic mouse model in which ERa can be inducibly overexpressed in animal tissues (ERa overexpressors). We dosed female controls and ERa overexpressors with sesame oil (vehicle control) or MXC (32 and 64 mg/kg/day) for 20 days. After dosing, the ovaries were collected for histological evaluation of follicle numbers and follicle atresia, while blood was collected for measurements of hormones. Estrous cycles were determined in all animals to ensure that all were terminated during estrus. Although there were no significant effects of MXC on the numbers of primordial, primary, and preantral follicles in both controls and ERa overexpressors, there was an effect on antral follicles. Specifically, our data indicate that 32 and 64 mg/kg MXC increased the percentage of atretic follicles compared to vehicle in both control and ERa overexpressor groups. Moreover, there was a clear trend toward greater sensitivity to 64 mg/kg MXC in ERa-overexpressing mice compared to control animals. Specifically, at the 64-mg/kg MXC dose, ERa-overexpressing mice had a significantly higher percentage of atretic follicles compared to control animals (controls ¼ 21.5 ± 3%, n ¼ 5; ERa overexpressors ¼ 37 ± 23%, n ¼ 9, p 0.05 vs. controls). After 20 days of dosing, there were no differences in estradiol levels between controls and ERa-overexpressing mice in all treatment groups. Follicle-stimulating hormone (FSH) levels were similar in sesame oil-treated control mice and control mice treated with 32 mg/kg MXC, while control mice treated with 64 mg/kg MXC had significantly lower levels of FSH compared to sesame oil-treated controls (sesame oil ¼ 4.31 ± 0.7, MXC [64 mg/kg/day] ¼ 1.89 ± 0.4, n ¼ 3, p 0.02 vs. sesame oil).

Facta universitatis - series: Architecture and Civil Engineering, 2015

The anatomical record. Part A, Discoveries in molecular, cellular, and evolutionary biology, 2003

Smad 3 is a signaling intermediate for the transforming growth factor beta (TGFbeta) family; howe... more Smad 3 is a signaling intermediate for the transforming growth factor beta (TGFbeta) family; however, little is known about the role this protein plays in the regulation of the ovarian surface epithelium (OSE). Using a transgenic mouse model, we found that in the absence of Smad 3 there was a distinct morphological alteration of OSE cells. Wild-type (WT) OSE was flat with thin cells, while Smad 3-deficient (Smad 3 -/-) OSE was thick with plump cuboidal cells. WT OSE had less immunostaining for proliferating cell nuclear antigen (PCNA) and estrogen receptor alpha (ERalpha) than Smad 3 -/- OSE. However, there were no differences in the number of apoptotic cells or Bax and Bcl-2 levels between WT and Smad 3 -/- OSE. Although WT mice had higher levels of serum estradiol than Smad 3 -/- mice, WT and Smad 3 -/- mice had similar levels of progesterone. These data suggest that Smad 3 regulates OSE morphological appearance and proliferation in the absence of high serum estradiol levels or al...

Facta universitatis - series: Architecture and Civil Engineering, 2011

Toxicology and Applied Pharmacology, 2007

The aryl hydrocarbon receptor (AHR) mediates the toxicity of a variety of environmental chemicals... more The aryl hydrocarbon receptor (AHR) mediates the toxicity of a variety of environmental chemicals. Although little is known about the physiological role of the AHR, studies suggest that it plays an important role in regulating ovulation because Ahr deficient (AhRKO) mice have a reduced number of ovulations compared to wild-type (WT) mice. The reasons for the reduced ability of AhRKO mice to ovulate are unknown. Normal ovulation, however, requires estrous cyclicity, appropriate luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels, and LH and FSH responsiveness. Thus, the purpose of this study was to test the hypothesis that Ahr deletion regulates ovulation by altering cyclicity, FSH and LH levels, follicle-stimulating hormone receptor (Fshr) and luteinizing hormone receptor (Lhcgr) levels and/or gonadotropin responsiveness. The data indicate that AhRKO and WT mice have similar levels of FSH and LH, but AhRKO mice have reduced Fshr and Lhcgr mRNA levels compared to WT mice. Furthermore, AhRKO ovaries contain fewer corpora lutea compared to WT ovaries after 5 IU equine chorionic gonadotropin (eCG) treatment. Lastly, both AhRKO and WT mice ovulate a similar number of eggs in response to 5 IU human chorionic gonadotropin (hCG), but AhRKO mice ovulate fewer eggs than WT mice in response to 2.5 IU and 1.25 IU hCG. Collectively, these data indicate that AhRKO follicles have a reduced capacity to ovulate compared to WT follicles and that this is due to reduced responsiveness to gonadotropins. Thus, in addition to mediating toxicity of environmental chemicals, the Ahr is required for normal ovulation.

Facta universitatis - series: Architecture and Civil Engineering, 2013

Toxicology and Applied Pharmacology, 2004

Chemicals found in the environment as industrial byproducts or pollutants as well as those that a... more Chemicals found in the environment as industrial byproducts or pollutants as well as those that are prescribed or part of our daily lives can have multiple effects on the human body. The manner in which we are exposed, and the levels we are exposed to are significant contributing factors. Adults have the bodily defense mechanisms in place to combat exposures to adverse toxicants and general pollution at a variety of levels. However, developing organisms may not have adequate defense mechanisms, and toxicants can have a significant effect on their health and development. In this review, we take particular note of the toxicities of chemicals on the developing female reproductive system as a result of in utero exposure. Environmental and prescribed chemicals such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), diethylstilbestrol, and genistein, as well as others, will be reviewed for their in utero toxicity in the neuroendocrine system, the ovary, oviduct, placenta, uterus, vagina, cervix, and mammary gland.

Toxicological Sciences, 2006

Although the ovarian surface epithelium (OSE) is responsive to hormones and endocrine-disrupting ... more Although the ovarian surface epithelium (OSE) is responsive to hormones and endocrine-disrupting chemicals, little information is available on the metabolizing capabilities of the OSE. Thus, we tested the hypothesis that the OSE is capable of expressing genes regulating phase I metabolism of estrogen and the estrogenic endocrine disruptor methoxychlor (MXC). To test this hypothesis, we isolated mouse OSE cells and cultured them with vehicle (dimethylsulfoxide; DMSO), 3 mM MXC, or 0.1 mM 17b-estradiol (E2) ± the anti-estrogen ICI 182,780 (1 mM) for 14 days. After culture, the cells were subjected to quantitative real-time polymerase chain reaction for cytochrome P450s (CYPs) 1A1, 1B1, 2C29, and 1A2, and estrogen receptor a (ERa). Our results indicate that E2 and MXC did not alter the expression of CYP1A1 or CYP1A2. In contrast, E2 significantly increased expression of CYP1B1 compared to controls (DMSO ¼ 0.93 ± 0.1, E2 ¼ 3.12 ± 0.64 genomic equivalents (GE), n ¼ 4, p 0.01). The E2-induced increase in CYP1B1 was abolished by co-treatment with ICI 182,780 (0.41 ± 0.17 GE). MXC treatment did not affect CYP1B1 expression. Both MXC and E2 increased expression of CYP2C29 (DMSO ¼ 0.02 ± 0.003; MXC ¼ 0.04 ± 0.008; E2 ¼ 0.46 ± 0.03 GE, n ¼ 4, p 0.05). MXC-and E2-induced elevations in CYP2C29

Toxicological Sciences, 2006

Methoxychlor (MXC) is a pesticide that is known to bind to estrogen receptor alpha (ERa) and to i... more Methoxychlor (MXC) is a pesticide that is known to bind to estrogen receptor alpha (ERa) and to induce atresia of antral ovarian follicles. Although studies have shown that MXC is toxic to the ovary, we hypothesize that perturbation to the estrogensignaling system (i.e., increase or decrease in estrogen sensitivity) might alter ovarian responsiveness to MXC. Thus, we examined whether ERa overexpression alters the ability of MXC to increase follicle atresia. To do so, we employed a transgenic mouse model in which ERa can be inducibly overexpressed in animal tissues (ERa overexpressors). We dosed female controls and ERa overexpressors with sesame oil (vehicle control) or MXC (32 and 64 mg/kg/day) for 20 days. After dosing, the ovaries were collected for histological evaluation of follicle numbers and follicle atresia, while blood was collected for measurements of hormones. Estrous cycles were determined in all animals to ensure that all were terminated during estrus. Although there were no significant effects of MXC on the numbers of primordial, primary, and preantral follicles in both controls and ERa overexpressors, there was an effect on antral follicles. Specifically, our data indicate that 32 and 64 mg/kg MXC increased the percentage of atretic follicles compared to vehicle in both control and ERa overexpressor groups. Moreover, there was a clear trend toward greater sensitivity to 64 mg/kg MXC in ERa-overexpressing mice compared to control animals. Specifically, at the 64-mg/kg MXC dose, ERa-overexpressing mice had a significantly higher percentage of atretic follicles compared to control animals (controls ¼ 21.5 ± 3%, n ¼ 5; ERa overexpressors ¼ 37 ± 23%, n ¼ 9, p 0.05 vs. controls). After 20 days of dosing, there were no differences in estradiol levels between controls and ERa-overexpressing mice in all treatment groups. Follicle-stimulating hormone (FSH) levels were similar in sesame oil-treated control mice and control mice treated with 32 mg/kg MXC, while control mice treated with 64 mg/kg MXC had significantly lower levels of FSH compared to sesame oil-treated controls (sesame oil ¼ 4.31 ± 0.7, MXC [64 mg/kg/day] ¼ 1.89 ± 0.4, n ¼ 3, p 0.02 vs. sesame oil).

Toxicological Sciences, 2004

While the pesticide methoxychlor (MXC) has a variety of adverse effects on the female reproductiv... more While the pesticide methoxychlor (MXC) has a variety of adverse effects on the female reproductive system, the effects of MXC on the ovarian surface epithelium (OSE) are unknown. Thus, this study tested the hypothesis that MXC alters the growth of the OSE. Mouse OSE cells were isolated by enzymatic digestion and cultured with vehicle, 3 mM of MXC, or 3 mM of 2,2-bis[ p-hydroxyphenyl]-1,1,1,trichloroethane (HPTE) for 14 days. After culture, proliferation and apoptosis were assessed by measurement of cell density, immunohistochemistry, and real-time polymerase chain reaction. Cell density was 66% greater for MXC-treated cells and 95% greater for HPTE-treated cells than controls ( p 0.05). The estrogen receptor blocker ICI 182,780 abolished MXC-and HPTE-induced increases in cell density. Proliferating cell nuclear antigen (PCNA) staining was positive in only 22 6 2.3% of controls, compared to 35 6 2.4% of MXC-treated cells and 40 6 2.4% of HPTE-treated cells ( p 0.05). The cell cycle regulators, cyclinD2 and cdk4, were significantly increased in MXC-and HPTE-treated cells compared to controls. The ApopTag assay demonstrated apoptotic cells in 4.8 6 0.45% of controls, 2.2 6 0.56% of MXC-treated cells, and 2.1 6 0.33% of HPTE-treated cells ( p 0.005). Expression of bcl-2 was significantly increased in MXC-and HPTE-treated cells, while bax was decreased in MXC-and HPTE-treated cells compared to controls. Collectively, these data indicate that MXC and HPTE stimulate OSE cell growth by increasing proliferation and inhibiting apoptosis. Further, since ICI 182,780 blocked MXC-and HPTE-induced OSE growth, these data suggest that the effects of MXC and HPTE on the OSE are mediated by estrogen receptors.

Reproductive Toxicology, 2007

Recently, we generated transgenic mice in which ERalpha can be inducibly overexpressed in reprodu... more Recently, we generated transgenic mice in which ERalpha can be inducibly overexpressed in reproductive tissues (ERalpha overexpressors). These mice were used to test the hypothesis that prenatal and postnatal ERalpha overexpression reduces female fertility. To do so, litter sizes, ovulation, follicle numbers, uterine histology, implantation sites, and hormone levels were compared in ERalpha overexpressors and controls. The data indicate that ERalpha overexpressors have reduced fertility compared to controls and that the reduced fertility is not due to reduced ovulatory capacity, altered levels of estradiol, FSH, and LH, or impaired follicular growth. ERalpha overexpressors, however, had a higher number of apoptotic cells in the endometrial epithelium and a reduced number of implantation sites compared to controls. Thus, the increased number of apoptotic cells and reduced number of implantation sites observed in ERalpha overexpressing uteri compared to controls may, in part, account for the reduced litter size produced by ERalpha overexpressing females.

This paper is based on the analysis of several international conventions and rules, as well as na... more This paper is based on the analysis of several international conventions and rules, as well as national regulations dealing with protection of rights of all members of community, especially preventing all potential forms of discrimination and with special focus on people with disabilities. Application of the European accessibility concept [i] would achieve the promotion of a new social model that would completely transform the relation towards the persons with disabilities. The concept suggests essentially different approach – treating the community as a whole, and thus all its needs and needs of each community member as one, making no difference among individual groups within the overall population, but provides the solutions that meet the conditions to fulfil the need of each individual member and the community as a whole. Terms: accessibility, access to all, inclusion, inclusive design, universal design, values/directions, principles, standards/norms/technical regulations, legisl...

On Architecture, international conference and exhibition, STRAND, 2013

This paper examines the potential resources in the educational process and research methodology i... more This paper examines the potential resources in the educational process and research methodology in the field of architectural and urban design, by positioning of the Blog as a formal framework of content and representation of contemporary architecture and as a tool that can contribute to the growing complexity of the knowledge base in the field of architecture. In this context, this paper examines two theses. The first one suggests that, used properly, a Blog can become a useful tool in the form and content of the research. This is based on the assumption that reflection of the architectural design process may have a significant influence on the development of architectural education, particularly in the area of information exchange and raising of the critical awareness about the problems of the specific topics in spatial, contextual and formal sense. The second theses encourages the development of blogs as a tool that may extend the interpretive potential of the representation in the field of architectural and urban design, by displacing it from the real to the virtual space and by giving it a value of the driver and initiator of possible changes. The paper also examines the ways in which the blog can establish, enhance, deepen or direct the already known and reliable methodological and conceptual basis of architectural education on the one side and representation of architectural and urban design, on the other side.

The application of colour in the architectural composition represents an effective instrument tha... more The application of colour in the architectural composition represents an effective instrument that can achieve a number of effects. Knowledge of its impact is a powerful tool in the hands of every architect. Warm and cool tones, by their nature, can cause various effects of depth, emphasis and suppression of certain elements to some extent. Colours can create the illusion of area increase and decrease and cause a number of other effects. The aim of this paper is focused on solid colour (monochromatic) architecture, with special reference to the usage of white colour. The colour is the most effective tool of distinguishing and perception. All of the visual appearance owes its existence to light and colour. The world of colour is not one source of countless tones, but is clearly designed on the basis of three primary colours and their combinations. Special mental attitude is required for a person to organize his world of colour in accordance with perceptual characteristics. Colour nam...

Facta Universitatis - Series: Architecture and Civil Engineering, 2020

Past urban planning practices for embassy buildings have largely been indifferent to environments... more Past urban planning practices for embassy buildings have largely been indifferent to environments and the context of cities, oftentimes causing negative effects on the urban matrix. Implementing a more open, transparent building process for its diplomatic outposts overseas, Japan has managed to contribute to overall city development, quality of its public spaces and the image it holds in host countries. These processes will be examined and findings elaborated for the new Japanese embassy in Belgrade, Serbia, how utilizing such methodology presents an improvement, in engineering and urban planning terms, as well as a new method of cultural sustainability.

Facta universitatis - series: Architecture and Civil Engineering, 2017

The aim of this paper is research of the potential and redefining of space of the contemporary ur... more The aim of this paper is research of the potential and redefining of space of the contemporary urban context, by recognizing movement and senses as principles of accessibility and affirmation of the neglected values of the city in regard to design aspects. A global context of networking transforms a modern city into processes of busy lifestyle, which neglect diversity and senses. Flows and networking, as the carriers of this context, despite their goal to create a connection between the global and the local and establish equality of all users, generate local separation and segregation, eliminating specific local traits and individual needs, thus neglecting individual units of space, social groups and subjects. The consequences of the city developing in this way are spatial fragments not connected to a network and not defined, and on the other hand neglected in a way that leads to specific environmental and sensory values, which under contemporary conditions propagate subjectivity, d...

Reproductive Toxicology, May 31, 2007

Reprod Toxicol, 2007

Recently, we generated transgenic mice in which ERα can be inducibly overexpressed in reproductiv... more Recently, we generated transgenic mice in which ERα can be inducibly overexpressed in reproductive tissues (ERα overexpressors). These mice were used to test the hypothesis that prenatal and postnatal ERα overexpression reduces female fertility. To do so, litter sizes, ovulation, follicle numbers, uterine histology, implantation sites, and hormone levels were compared in ERα overexpressors and controls. The data indicate that ERα overexpressors have reduced fertility compared to controls and that the reduced fertility is not due to reduced ovulatory capacity, altered levels of estradiol, FSH, and LH, or impaired follicular growth. ERα overexpressors, however, had a higher number of apoptotic cells in the endometrial epithelium and a reduced number of implantation sites compared to controls. Thus, the increased number of apoptotic cells and reduced number of implantation sites observed in ERα overexpressing uteri compared to controls may, in part, account for the reduced litter size produced by ERα overexpressing females.

Molecular Endocrinology, Jul 2, 2013

Smad3 is an important mediator of the TGF beta signaling pathway. Interestingly, Smad3-deficient ... more Smad3 is an important mediator of the TGF beta signaling pathway. Interestingly, Smad3-deficient (Smad3-/-) mice have reduced fertility compared with wild-type (WT) mice. To better understand the molecular mechanisms underlying the reduced fertility in Smad3-/- animals, this work tested the hypothesis that Smad3 deficiency interferes with three critical aspects of folliculogenesis: growth, atresia, and differentiation. Growth was assessed by comparing the size of follicles, expression of proliferating cell nuclear antigen, and expression of cell cycle genes in Smad3-/- and WT mice. Atresia was assessed by comparing the incidence of atresia and expression of bcl-2 genes involved in cell death and cell survival in Smad3-/- and WT mice. Differentiation was assessed by comparing the expression of FSH receptor (FSHR), estrogen receptor (ER) alpha, ER beta, and inhibin alpha-, beta(A)-, and beta(B)-subunits in Smad3-/- and WT mice. Because growth, atresia, and differentiation are regulated by hormones, estradiol, FSH, and LH levels were compared in Smad3-/- and WT mice. Moreover, because alterations in folliculogenesis can affect the ability of mice to ovulate, the number of corpora lutea and ovulated eggs in response to gonadotropin treatments were compared in Smad3-/- and WT animals. The results indicate that Smad3 deficiency slows follicle growth, which is characterized by small follicle diameters, low levels of proliferating cell nuclear antigen, and low expression of cell cycle genes (cyclin-dependent kinase 4 and cyclin D2). Smad3 deficiency also causes atretic follicles, degenerated oocytes, and low expression of bcl-2. Furthermore, Smad3 deficiency affects follicular differentiation as evidenced by decreased expression of ER beta, increased expression of ER alpha, and decreased expression of inhibin alpha-subunits. Smad3 deficiency causes low estradiol and high FSH levels. Finally, Smad3-/- ovaries have no corpora lutea, and they do not ovulate after ovulatory induction with exogenous gonadotropins. Collectively, these data provide the first evidence that reduced fertility in Smad3-/- mice is due to impaired folliculogenesis, associated with altered expression of genes that control cell cycle progression, cell survival, and cell differentiation. The findings that Smad3-/- follicles have impaired growth, increased atresia, and altered differentiation in the presence of high FSH levels, normal expression of FSHR, and lower expression of cyclin D2, suggest a possible interaction between Smad3 and FSH signaling downstream of FSHR in the mouse ovary.

Toxicol Sci, 2006

Methoxychlor (MXC) is a pesticide that is known to bind to estrogen receptor alpha (ERa) and to i... more Methoxychlor (MXC) is a pesticide that is known to bind to estrogen receptor alpha (ERa) and to induce atresia of antral ovarian follicles. Although studies have shown that MXC is toxic to the ovary, we hypothesize that perturbation to the estrogensignaling system (i.e., increase or decrease in estrogen sensitivity) might alter ovarian responsiveness to MXC. Thus, we examined whether ERa overexpression alters the ability of MXC to increase follicle atresia. To do so, we employed a transgenic mouse model in which ERa can be inducibly overexpressed in animal tissues (ERa overexpressors). We dosed female controls and ERa overexpressors with sesame oil (vehicle control) or MXC (32 and 64 mg/kg/day) for 20 days. After dosing, the ovaries were collected for histological evaluation of follicle numbers and follicle atresia, while blood was collected for measurements of hormones. Estrous cycles were determined in all animals to ensure that all were terminated during estrus. Although there were no significant effects of MXC on the numbers of primordial, primary, and preantral follicles in both controls and ERa overexpressors, there was an effect on antral follicles. Specifically, our data indicate that 32 and 64 mg/kg MXC increased the percentage of atretic follicles compared to vehicle in both control and ERa overexpressor groups. Moreover, there was a clear trend toward greater sensitivity to 64 mg/kg MXC in ERa-overexpressing mice compared to control animals. Specifically, at the 64-mg/kg MXC dose, ERa-overexpressing mice had a significantly higher percentage of atretic follicles compared to control animals (controls ¼ 21.5 ± 3%, n ¼ 5; ERa overexpressors ¼ 37 ± 23%, n ¼ 9, p 0.05 vs. controls). After 20 days of dosing, there were no differences in estradiol levels between controls and ERa-overexpressing mice in all treatment groups. Follicle-stimulating hormone (FSH) levels were similar in sesame oil-treated control mice and control mice treated with 32 mg/kg MXC, while control mice treated with 64 mg/kg MXC had significantly lower levels of FSH compared to sesame oil-treated controls (sesame oil ¼ 4.31 ± 0.7, MXC [64 mg/kg/day] ¼ 1.89 ± 0.4, n ¼ 3, p 0.02 vs. sesame oil).

Facta universitatis - series: Architecture and Civil Engineering, 2015

The anatomical record. Part A, Discoveries in molecular, cellular, and evolutionary biology, 2003

Smad 3 is a signaling intermediate for the transforming growth factor beta (TGFbeta) family; howe... more Smad 3 is a signaling intermediate for the transforming growth factor beta (TGFbeta) family; however, little is known about the role this protein plays in the regulation of the ovarian surface epithelium (OSE). Using a transgenic mouse model, we found that in the absence of Smad 3 there was a distinct morphological alteration of OSE cells. Wild-type (WT) OSE was flat with thin cells, while Smad 3-deficient (Smad 3 -/-) OSE was thick with plump cuboidal cells. WT OSE had less immunostaining for proliferating cell nuclear antigen (PCNA) and estrogen receptor alpha (ERalpha) than Smad 3 -/- OSE. However, there were no differences in the number of apoptotic cells or Bax and Bcl-2 levels between WT and Smad 3 -/- OSE. Although WT mice had higher levels of serum estradiol than Smad 3 -/- mice, WT and Smad 3 -/- mice had similar levels of progesterone. These data suggest that Smad 3 regulates OSE morphological appearance and proliferation in the absence of high serum estradiol levels or al...

Facta universitatis - series: Architecture and Civil Engineering, 2011

Toxicology and Applied Pharmacology, 2007

The aryl hydrocarbon receptor (AHR) mediates the toxicity of a variety of environmental chemicals... more The aryl hydrocarbon receptor (AHR) mediates the toxicity of a variety of environmental chemicals. Although little is known about the physiological role of the AHR, studies suggest that it plays an important role in regulating ovulation because Ahr deficient (AhRKO) mice have a reduced number of ovulations compared to wild-type (WT) mice. The reasons for the reduced ability of AhRKO mice to ovulate are unknown. Normal ovulation, however, requires estrous cyclicity, appropriate luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels, and LH and FSH responsiveness. Thus, the purpose of this study was to test the hypothesis that Ahr deletion regulates ovulation by altering cyclicity, FSH and LH levels, follicle-stimulating hormone receptor (Fshr) and luteinizing hormone receptor (Lhcgr) levels and/or gonadotropin responsiveness. The data indicate that AhRKO and WT mice have similar levels of FSH and LH, but AhRKO mice have reduced Fshr and Lhcgr mRNA levels compared to WT mice. Furthermore, AhRKO ovaries contain fewer corpora lutea compared to WT ovaries after 5 IU equine chorionic gonadotropin (eCG) treatment. Lastly, both AhRKO and WT mice ovulate a similar number of eggs in response to 5 IU human chorionic gonadotropin (hCG), but AhRKO mice ovulate fewer eggs than WT mice in response to 2.5 IU and 1.25 IU hCG. Collectively, these data indicate that AhRKO follicles have a reduced capacity to ovulate compared to WT follicles and that this is due to reduced responsiveness to gonadotropins. Thus, in addition to mediating toxicity of environmental chemicals, the Ahr is required for normal ovulation.

Facta universitatis - series: Architecture and Civil Engineering, 2013

Toxicology and Applied Pharmacology, 2004

Chemicals found in the environment as industrial byproducts or pollutants as well as those that a... more Chemicals found in the environment as industrial byproducts or pollutants as well as those that are prescribed or part of our daily lives can have multiple effects on the human body. The manner in which we are exposed, and the levels we are exposed to are significant contributing factors. Adults have the bodily defense mechanisms in place to combat exposures to adverse toxicants and general pollution at a variety of levels. However, developing organisms may not have adequate defense mechanisms, and toxicants can have a significant effect on their health and development. In this review, we take particular note of the toxicities of chemicals on the developing female reproductive system as a result of in utero exposure. Environmental and prescribed chemicals such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), diethylstilbestrol, and genistein, as well as others, will be reviewed for their in utero toxicity in the neuroendocrine system, the ovary, oviduct, placenta, uterus, vagina, cervix, and mammary gland.

Toxicological Sciences, 2006

Although the ovarian surface epithelium (OSE) is responsive to hormones and endocrine-disrupting ... more Although the ovarian surface epithelium (OSE) is responsive to hormones and endocrine-disrupting chemicals, little information is available on the metabolizing capabilities of the OSE. Thus, we tested the hypothesis that the OSE is capable of expressing genes regulating phase I metabolism of estrogen and the estrogenic endocrine disruptor methoxychlor (MXC). To test this hypothesis, we isolated mouse OSE cells and cultured them with vehicle (dimethylsulfoxide; DMSO), 3 mM MXC, or 0.1 mM 17b-estradiol (E2) ± the anti-estrogen ICI 182,780 (1 mM) for 14 days. After culture, the cells were subjected to quantitative real-time polymerase chain reaction for cytochrome P450s (CYPs) 1A1, 1B1, 2C29, and 1A2, and estrogen receptor a (ERa). Our results indicate that E2 and MXC did not alter the expression of CYP1A1 or CYP1A2. In contrast, E2 significantly increased expression of CYP1B1 compared to controls (DMSO ¼ 0.93 ± 0.1, E2 ¼ 3.12 ± 0.64 genomic equivalents (GE), n ¼ 4, p 0.01). The E2-induced increase in CYP1B1 was abolished by co-treatment with ICI 182,780 (0.41 ± 0.17 GE). MXC treatment did not affect CYP1B1 expression. Both MXC and E2 increased expression of CYP2C29 (DMSO ¼ 0.02 ± 0.003; MXC ¼ 0.04 ± 0.008; E2 ¼ 0.46 ± 0.03 GE, n ¼ 4, p 0.05). MXC-and E2-induced elevations in CYP2C29

Toxicological Sciences, 2006

Methoxychlor (MXC) is a pesticide that is known to bind to estrogen receptor alpha (ERa) and to i... more Methoxychlor (MXC) is a pesticide that is known to bind to estrogen receptor alpha (ERa) and to induce atresia of antral ovarian follicles. Although studies have shown that MXC is toxic to the ovary, we hypothesize that perturbation to the estrogensignaling system (i.e., increase or decrease in estrogen sensitivity) might alter ovarian responsiveness to MXC. Thus, we examined whether ERa overexpression alters the ability of MXC to increase follicle atresia. To do so, we employed a transgenic mouse model in which ERa can be inducibly overexpressed in animal tissues (ERa overexpressors). We dosed female controls and ERa overexpressors with sesame oil (vehicle control) or MXC (32 and 64 mg/kg/day) for 20 days. After dosing, the ovaries were collected for histological evaluation of follicle numbers and follicle atresia, while blood was collected for measurements of hormones. Estrous cycles were determined in all animals to ensure that all were terminated during estrus. Although there were no significant effects of MXC on the numbers of primordial, primary, and preantral follicles in both controls and ERa overexpressors, there was an effect on antral follicles. Specifically, our data indicate that 32 and 64 mg/kg MXC increased the percentage of atretic follicles compared to vehicle in both control and ERa overexpressor groups. Moreover, there was a clear trend toward greater sensitivity to 64 mg/kg MXC in ERa-overexpressing mice compared to control animals. Specifically, at the 64-mg/kg MXC dose, ERa-overexpressing mice had a significantly higher percentage of atretic follicles compared to control animals (controls ¼ 21.5 ± 3%, n ¼ 5; ERa overexpressors ¼ 37 ± 23%, n ¼ 9, p 0.05 vs. controls). After 20 days of dosing, there were no differences in estradiol levels between controls and ERa-overexpressing mice in all treatment groups. Follicle-stimulating hormone (FSH) levels were similar in sesame oil-treated control mice and control mice treated with 32 mg/kg MXC, while control mice treated with 64 mg/kg MXC had significantly lower levels of FSH compared to sesame oil-treated controls (sesame oil ¼ 4.31 ± 0.7, MXC [64 mg/kg/day] ¼ 1.89 ± 0.4, n ¼ 3, p 0.02 vs. sesame oil).

Toxicological Sciences, 2004

While the pesticide methoxychlor (MXC) has a variety of adverse effects on the female reproductiv... more While the pesticide methoxychlor (MXC) has a variety of adverse effects on the female reproductive system, the effects of MXC on the ovarian surface epithelium (OSE) are unknown. Thus, this study tested the hypothesis that MXC alters the growth of the OSE. Mouse OSE cells were isolated by enzymatic digestion and cultured with vehicle, 3 mM of MXC, or 3 mM of 2,2-bis[ p-hydroxyphenyl]-1,1,1,trichloroethane (HPTE) for 14 days. After culture, proliferation and apoptosis were assessed by measurement of cell density, immunohistochemistry, and real-time polymerase chain reaction. Cell density was 66% greater for MXC-treated cells and 95% greater for HPTE-treated cells than controls ( p 0.05). The estrogen receptor blocker ICI 182,780 abolished MXC-and HPTE-induced increases in cell density. Proliferating cell nuclear antigen (PCNA) staining was positive in only 22 6 2.3% of controls, compared to 35 6 2.4% of MXC-treated cells and 40 6 2.4% of HPTE-treated cells ( p 0.05). The cell cycle regulators, cyclinD2 and cdk4, were significantly increased in MXC-and HPTE-treated cells compared to controls. The ApopTag assay demonstrated apoptotic cells in 4.8 6 0.45% of controls, 2.2 6 0.56% of MXC-treated cells, and 2.1 6 0.33% of HPTE-treated cells ( p 0.005). Expression of bcl-2 was significantly increased in MXC-and HPTE-treated cells, while bax was decreased in MXC-and HPTE-treated cells compared to controls. Collectively, these data indicate that MXC and HPTE stimulate OSE cell growth by increasing proliferation and inhibiting apoptosis. Further, since ICI 182,780 blocked MXC-and HPTE-induced OSE growth, these data suggest that the effects of MXC and HPTE on the OSE are mediated by estrogen receptors.

Reproductive Toxicology, 2007

Recently, we generated transgenic mice in which ERalpha can be inducibly overexpressed in reprodu... more Recently, we generated transgenic mice in which ERalpha can be inducibly overexpressed in reproductive tissues (ERalpha overexpressors). These mice were used to test the hypothesis that prenatal and postnatal ERalpha overexpression reduces female fertility. To do so, litter sizes, ovulation, follicle numbers, uterine histology, implantation sites, and hormone levels were compared in ERalpha overexpressors and controls. The data indicate that ERalpha overexpressors have reduced fertility compared to controls and that the reduced fertility is not due to reduced ovulatory capacity, altered levels of estradiol, FSH, and LH, or impaired follicular growth. ERalpha overexpressors, however, had a higher number of apoptotic cells in the endometrial epithelium and a reduced number of implantation sites compared to controls. Thus, the increased number of apoptotic cells and reduced number of implantation sites observed in ERalpha overexpressing uteri compared to controls may, in part, account for the reduced litter size produced by ERalpha overexpressing females.