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Embryonic Life (embryonic + life)
Selected AbstractsReligion and Reproductive Genetics: Beyond Views of Embryonic Life?JOURNAL FOR THE SCIENTIFIC STUDY OF RELIGION, Issue 4 2007JOHN H. EVANS Advances in new reproductive genetic technologies have spawned a very polarized public and political debate. As with the abortion debate, most formal opposition to these technologies comes from religious organizations that are concerned about embryonic and fetal life. In this article we conduct an analysis of the first nationally representative opinion survey on religion and reproductive genetics. We find, as in the abortion debate, that evangelicals, fundamentalists, and traditionalist Catholics are more opposed than more liberal religious groups. When we compare respondents with the same views on embryonic life, we find that differences remain in the level of approval for genetic technologies, suggesting that there is more to this debate than concern about embryos. We also find that religious conservatives are more distinct from the religious nonattenders in their views of health objectives of reproductive genetic technologies and less distinct in their views of improvement objectives. [source] Embryo-maternal Communication during the First Days of Embryonic LifeANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 2005S. Kölle The mechanisms of embryo-maternal communication during the first days of embryonic life are largely unknown. Using the bovine as a model, the aims of our study were to morphologically characterize the interaction between the pre-implantation embryo and the epithelium of the maternal ampulla, isthmus and uterotubal junction by light and scanning electron microscopy. For this purpose, oviducts were removed from cows revealing a functional corpus luteum on day 3 after insemination. These were compared to oviducts removed on day 3 (metestrus) of the estrous cycle. Three days after insemination, the majority of the epithelial cells in the ampulla were secretory cells distinctly protruding into the oviductal lumen. Contrary the ampulla of cows on day 3 of the cycle predominantly revealed ciliated cells in the oviductal epithelium. As shown by Periodic Acid Schiff reaction (PAS) with and without amylase digestion, the secretory cells of the ampulla synthesized merely glycoproteins during metestrus, but large amounts of glycogen during pregnancy. In the isthmus no morphological differences were seen between pregnant and cyclic cows. The most conspicuous finding during pregnancy was seen in the uterotubal junction: Vital cumulus cells embedded in between epithelial cells had developed short cytoplasmic processes intensely contacting the epithelial uterine cells. The embryos obtained ex vivo were regularly covered with a thick layer of homogenous extracellular matrix. Contrary embryos produced in vitro, both with and without coculture with oviductal cells ,revealed a clearly visible zona pellucida with spongy appearance and numerous pores. Our results imply that already during the first days of life there is intense interaction of the pre-implantation embryo and the maternal genital tract part of which may be mediated by cumulus cells. [source] Effects of fungicides on thyroid function, metabolism, and thermoregulation in cotton rats,ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 8 2001Thomas E. Tomasi Abstract Among the myriad of recent studies on endocrine-disrupting chemicals, relatively few involve thyroid disruption, and most of these address exposure/disruption during embryonic life. Of those involving adult vertebrates, the endpoints examined are thyroid measurements. Even though thyroid disruption could potentially interfere with energy metabolism and thermoregulation such that over-winter survival might be compromised, the possible energetic consequences of these thyroid perturbations have not been investigated. We assessed thyroid function and measured resting metabolic rates of cotton rats chronically exposed to the fungicides vinclozolin or mancozeb. In addition, we measured norepinephrine-induced nonshivering thermogenesis and cold-induced thermogenesis and then cold-acclimated the mancozeb animals. Although thyroid hormone concentrations generally decreased, this was compensated for by an increase in thyroxine turnover (vinclozolin study only) such that thyroxine utilization rate was not different. In addition, there was no difference between the treated and control animals in any of the metabolic parameters measured. It is concluded that wild rodents exposed to these compounds are not energetically compromised. [source] Epidermal Growth Factor Regulates Amino Acid Transport in Chick Embryo Hepatocytes via Protein Kinase CEXPERIMENTAL PHYSIOLOGY, Issue 4 2000Maria Marino System A-mediated amino acid transport, activation of different steps of signal transduction and involvement of different isoforms of protein kinase C (PKC) have been investigated in chick embryo hepatocytes after epidermal growth factor (EGF) stimulation. EGF rapidly (10 min) increased the rate of aminoisobutyric acid (AIB) uptake in chick embryo hepatocytes freshly isolated on the 19th day of embryonic life, while no change was detectable at other embryonal stages. The growth factor stimulation was abolished by PKC and tyrosine kinase inhibitors and was mimicked by 4-phorbol-12-myristate-13-acetate, dimethyl-2 (PMA). EGF treatment did not modify the phosphorylation of the , isoform of phospholipase C (PLC-,), and inositol trisphosphate (IP3) and intracellular calcium levels, but it induced an increase in PKC activity. Our data show that EGF regulates amino acid uptake, via PKC and without PLC-, activation, only in the last period of chick embryo hepatocyte development. The effects of growth factor on PKC activity suggest the involvement of PKC-, and -, isoforms in EGF modulation of amino acid transport. [source] The chicken B-cell receptor complex and its role in avian B-cell developmentIMMUNOLOGICAL REVIEWS, Issue 1 2000Camil E. Sayegh Summary: The bursa of Fabricius is critical to normal B-lymphocyte development in birds. During embryonic life, B-cell precursors migrate to the bursal rudiment and those which have undergone productive V(D)J recombination colonize lymphoid follicles and undergo immunoglobulin V gene diversification by gene conversion. The chicken surface IgM complex appears structurally and functionally equivalent to its mammalian counterpart, with homologs to CD79a and CD79b. Expression of a truncated Ig chain is sufficient to drive the early stages of B-cell development in the embryo bursa. Bursal cells expressing the truncated receptor complex proliferate in bursal follicles, and those which contain V gene rearrangements undergo V gene diversification by gene conversion. The bursa is a gut-associated organ and antigen is focused to bursal lymphoid follicles after hatch. While expression of the truncated chain is sufficient to support B-cell development in the embryo, B cells expressing this receptor are rapidly eliminated after hatch. We suggest the possibility that B-cell development in the bursa after hatch is driven by encounter with antigen leading to redistribution of B cells within the lymphoid follicle, B-cell proliferation and V gene repertoire development by gene conversion. [source] Religion and Reproductive Genetics: Beyond Views of Embryonic Life?JOURNAL FOR THE SCIENTIFIC STUDY OF RELIGION, Issue 4 2007JOHN H. EVANS Advances in new reproductive genetic technologies have spawned a very polarized public and political debate. As with the abortion debate, most formal opposition to these technologies comes from religious organizations that are concerned about embryonic and fetal life. In this article we conduct an analysis of the first nationally representative opinion survey on religion and reproductive genetics. We find, as in the abortion debate, that evangelicals, fundamentalists, and traditionalist Catholics are more opposed than more liberal religious groups. When we compare respondents with the same views on embryonic life, we find that differences remain in the level of approval for genetic technologies, suggesting that there is more to this debate than concern about embryos. We also find that religious conservatives are more distinct from the religious nonattenders in their views of health objectives of reproductive genetic technologies and less distinct in their views of improvement objectives. [source] Ontogeny of Plurihormonal Cells in the Anterior Pituitary of the Mouse, as Studied by Means of Hormone mRNA Detection in Single CellsJOURNAL OF NEUROENDOCRINOLOGY, Issue 8 2002E. Seuntjens Abstract The expression of mRNA of growth hormone (GH), prolactin (PRL), pro-opiomelanocortin (POMC) and the common glycoprotein hormone ,-subunit (,GSU) was studied by means of single cell reverse transcriptase-polymerase chain reaction in male mouse pituitary cells at key time points of fetal and postnatal development: embryonic day 16 (E16); postnatal day 1 (P1) and young-adult age (P38). At E16, the hormone mRNAs examined were detectable, although only in 44% of total cells. Most of the hormone-positive cells expressed only one of the tested hormone mRNAs (monohormonal) but 14% of them contained more than one hormone mRNA (plurihormonal cells). Combinations of GH mRNA with PRL mRNA, of ,GSU mRNA with GH and/or PRL mRNA and of POMC mRNA with GH and/or PRL mRNA or ,GSU mRNA were found. As expected, the proportion of hormone-positive cells rose as the mouse aged. The proportions of plurihormonal cells followed a developmental pattern independent of that of monohormonal cells and characteristic for each hormone mRNA examined. Cells coexpressing POMC mRNA with GH or PRL mRNA significantly rose in proportion between E16 and P1, while the proportion of cells coexpressing GH and PRL mRNA markedly increased between P1 and P38. The occurrence of cells displaying combined expression of ,GSU mRNA with GH and/or PRL mRNA did not significantly change during development. Remarkably, the population of cells expressing PRL mRNA only, was larger at E16 than at P1 and expanded again thereafter. In conclusion, the normal mouse pituitary develops a cell population that is capable of expressing multiple hormone mRNAs, thereby combining typical phenotypes of different cell lineages. These plurihormonal cells are already present during embryonic life. This population is of potential physiological relevance because development-related factors appear to determine which hormone mRNAs are preferentially coexpressed. Coexpression of multiple hormone mRNAs may represent a mechanism to respond to temporally increased endocrine demands. The data also suggest that the control of combined hormone expression is different from that of single hormone expression, raising questions about the current view on pituitary cell lineage specifications. [source] Embryo-maternal Communication during the First Days of Embryonic LifeANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 2005S. Kölle The mechanisms of embryo-maternal communication during the first days of embryonic life are largely unknown. Using the bovine as a model, the aims of our study were to morphologically characterize the interaction between the pre-implantation embryo and the epithelium of the maternal ampulla, isthmus and uterotubal junction by light and scanning electron microscopy. For this purpose, oviducts were removed from cows revealing a functional corpus luteum on day 3 after insemination. These were compared to oviducts removed on day 3 (metestrus) of the estrous cycle. Three days after insemination, the majority of the epithelial cells in the ampulla were secretory cells distinctly protruding into the oviductal lumen. Contrary the ampulla of cows on day 3 of the cycle predominantly revealed ciliated cells in the oviductal epithelium. As shown by Periodic Acid Schiff reaction (PAS) with and without amylase digestion, the secretory cells of the ampulla synthesized merely glycoproteins during metestrus, but large amounts of glycogen during pregnancy. In the isthmus no morphological differences were seen between pregnant and cyclic cows. The most conspicuous finding during pregnancy was seen in the uterotubal junction: Vital cumulus cells embedded in between epithelial cells had developed short cytoplasmic processes intensely contacting the epithelial uterine cells. The embryos obtained ex vivo were regularly covered with a thick layer of homogenous extracellular matrix. Contrary embryos produced in vitro, both with and without coculture with oviductal cells ,revealed a clearly visible zona pellucida with spongy appearance and numerous pores. Our results imply that already during the first days of life there is intense interaction of the pre-implantation embryo and the maternal genital tract part of which may be mediated by cumulus cells. [source] | |||||||||||||