Endocrine Active Compounds Actions during Neonatal Period: Effect on the Ovary

Many female reproductive disorders observed during adulthood originate from the neonatal period, which is a critical stage toward the reproductive potency. Human and animal fertility are determined by the pool of primordial follicles that are established during fetal or neonatal life. The earliest stages of follicle development are under control of a variety of factors, including sex steroids. Neonatal period is a “critical developmental window” in which organisms are susceptible to the environmental chemicals that may affect the reproductive health. Endocrine active compounds (EACs) are found abundantly in the environment and interfere with sex steroids (predominantly androgens and estrogens) by either mimicking or blocking their functions. This review covers the current knowledge about the effects of selected EACs with androgenic (testosterone propionate), anti-androgenic (flutamide), estrogenic (diethylstilbestrol, bisphenol A, 4-tert-octylphenol, phtalates and genistein), anti-estrogenic (ICI 182,780 and parabens), or mixed activity (methoxychlor) on the ovary of neonates, focusing on their effects on the early stages of folliculogenesis. These chemicals have been shown to affect oocyte survival, follicle formation, and growth, as well as steroidogenic functions. The better cognition of mechanisms underlying the long-term consequences of the neonatal EACs exposure may in future lead to an understanding of human health risks and developing prevention strategies

The impact of antiandrogen flutamide on the hypoxia inducible factor 1a and vascular endothelial growth factor A gene and protein expression in the pig placenta during late pregnancy

Introduction. In contrast to estradiol action, little is known about androgen signaling in placental development. The purpose of this study was to evaluate the impact of diminished androgen action on hypoxia inducible factor 1a (HIF-1a) and vascular endothelial growth factor A (VEGFA) protein expression as well as their mRNAs in the structures of fetal and maternal parts of porcine placenta during late pregnancy. Material and methods. Pregnant pigs were injected daily with antiandrogen flutamide, at a dose of 50 mg/kg body weight at different stages of pregnancy: between gestational days 83–89 (90 dpc) and 101–107 (108 dpc). Control groups (90 dpc or 108 dpc) were treated with vehicle (corn oil). One day after the last injection animals were sacrificed and tissues were collected. Tissue samples were frozen for mRNA isolation or fixed for immu­nohistochemistry (IHC). The expression of HIF-1a and VEGFA were investigated by real-time PCR and IHC. Results. Flutamide treatment caused changes in both HIF-1a and VEGFA mRNA levels only in the placentas of the 90 dpc group. Relative optical density analysis showed decreased HIF-1a and increased VEGFA protein expression in the placentas obtained from flutamide-treated 108 dpc group while no differences were observed in the 90 dpc group. Conclusions. Experimentally induced androgen deficiency in pigs deregulates the expression of some genes important for placental blood circulation. We suggest that androgens are involved in the control of expression of HIF-1a and VEGFA in porcine placenta during late pregnancy

Structure-based discovery and in-parallel optimization of novelcompetitive inhibitors of thymidylate synthase

AbstractBackground:The substrate sites of enzymes are attractive targets for structurebased inhibitor design. Two difficulties hinder efforts to discover and elaborate new (nonsubstrate-like) inhibitors for these sites. First, novel inhibitors often bind at nonsubstrate sites. Second, a novel scaffold introduces chemistry that is frequently unfamiliar, making synthetic elaboration challenging.Results:In an effort to discover and elaborate a novel scaffold for a substrate site, we combined structure-based screening with in-parallel synthetic elaboration. These techniques were used to find new inhibitors that bound to the folate site of Lactobacillus casei thymidylate synthase (LcTS), an enzyme that is a potential target for proliferative diseases, and is highly studied. The available chemicals directory was screened, using a molecular-docking computer program, for molecules that complemented the three-dimensional structure of this site. Five high-ranking compounds were selected for testing. Activity and clocking studies led to a derivative of one of these, dansyltyrosine (Ki 65 μM. Using solid-phase in-parallel techniques 33 derivatives of this lead were synthesized and tested. These analogs are dissimilar to the substrate but bind competitively with it. The most active analog had a Ki of 1.3 μM. The tighter binding inhibitors were also the most specific for LcTS versus related enzymes.Conclusions:TS can recognize inhibitors that are dissimilar to, but that bind competitively with, the folate substrate. Combining structure-based discovery with in-parallel synthetic techniques allowed the rapid elaboration of this series of compounds. More automated versions of this approach can be envisaged

Effects of pre- and post- natal exposure to flutamide on connexin 43 expression in testes and ovaries of prepubertal pigs

The aim of this study was to show whether connexin43 (C×43) expression in gonads is affected by an anti-androgen action. To perform this test, pigs were prenatally (on gestational days 20–28 and 80–88; GD20, GD80) and postnatally (on days 2–10 after birth; PD2) exposed to flutamide, which was given in five doses every second day and its effect was observed in prepubertal gilts and boars. Morphology and expression of C×43 was investigated in testes and ovaries by means of routine histology, immunohistochemistry, Western blotting, and RT-PCR. In boars exposed to flutamide varying degrees of seminiferous tubule abnormality, including reduced number of Sertoli cells, tubules with severely dilated lumina and multinucleated germ cells were observed, whereas in gilts, the administration of flutamide at GD20 resulted in delayed folliculogenesis. Only follicles at the preantral stage were observed. Qualitative analysis of immunohistochemical staining for C×43 was confirmed by quantitative image analysis, where the staining intensity was expressed as relative optical density of diaminobenzidine deposits. After flutamide exposure, statistically significant increase in C×43 signal intensity was observed between interstitial tissue of GD20 and control pigs (**P<0.01), between seminiferous tubules of PD2 and control boars (**P<0.01) and between theca cells of GD80, of PD2 and control gilts (**P<0.01). In contrast, statistically significant decrease in C×43 signal intensity was found between granulosa cells of GD20, of PD2 and control gilts (**P<0.01 and *P<0.05, respectively) and between theca cells of GD20 and control gilts (**P<0.01). Since we demonstrated changes in gonad morphology and in the expression of C×43 at the level of protein of prepubertal boars and gilts, it seems possible that flutamide, through blocking androgen action, causes delayed gonadal maturation in later postnatal life and, among other factors, may be involved in the regulation of C×43 gene expression in pig gonads

The tangible assets in accordance with IFRS

Bachelor thesis is focused on the characteristics of tangible assets in accordance with IFRS and the implementation of standards in particular companies. Work consists of two parts; the theoretical part defines the subject of tangible assets in accordance with IFRS and the practical part deals with the comparison of the reported tangible fixed assets in the companies' accounting. Based on the financial statements, procedures and accounting policies that apply to those assets are evaluated