Talk:Abnormal Development - Environmental: Difference between revisions
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==2009== | |||
===The Pine River statement: human health consequences of DDT use=== | ===The Pine River statement: human health consequences of DDT use=== | ||
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CONCLUSIONS: Although we provide evidence to suggest that DDT and DDE may pose a risk to human health, we also highlight the lack of knowledge about human exposure and health effects in communities where DDT is currently being sprayed for malaria control. We recommend research to address this gap and to develop safe and effective alternatives to DDT. | CONCLUSIONS: Although we provide evidence to suggest that DDT and DDE may pose a risk to human health, we also highlight the lack of knowledge about human exposure and health effects in communities where DDT is currently being sprayed for malaria control. We recommend research to address this gap and to develop safe and effective alternatives to DDT. | ||
PMID: | PMID 19750098 | ||
==2007== | |||
===The effect of hypoxia in development=== | |||
Birth Defects Res C Embryo Today. 2007 Sep;81(3):215-28. | |||
Webster WS, Abela D. | |||
Source | |||
Department of Anatomy and Histology, University of Sydney, Sydney, Australia. billweb@anatomy.usyd.edu.au | |||
Abstract | |||
There is increasing evidence that the oxygen supply to the human embryo in the first trimester is tightly controlled, suggesting that too much oxygen may interfere with development. The use of hypoxia probes in mammalian embryos during the organogenic period indicates that the embryo is normally in a state of partial hypoxia, and this may be essential to control cardiovascular development, perhaps under the control of hypoxia-inducible factor (HIF). A consequence of this state of partial hypoxia is that disturbances in the oxygen supply can more easily lead to a damaging degree of hypoxia. Experimental mammalian embryos show a surprising degree of resilience to hypoxia, with many organogenic stage embryos able to survive 30-60 min of anoxia. However, in some embryos this degree of hypoxia causes abnormal development, particularly transverse limb reduction defects. These abnormalities are preceded by hemorrhage/edema and tissue necrosis. Other parts of the embryo are also susceptible to this hypoxia-induced damage and include the genital tubercle, the developing nose, the tail, and the central nervous system. Other frequently observed defects in animal models of prenatal hypoxia include cleft lip, maxillary hypoplasia, and heart defects. Animal studies indicate that hypoxic episodes in the first trimester of human pregnancy could occur by temporary constriction of the uterine arteries. This could be a consequence of exposure to cocaine, misoprostol, or severe shock, and there is evidence that these exposures have resulted in hypoxia-related malformations in the human. Exposure to drugs that block the potassium current (IKr) can cause severe slowing and arrhythmia of the mammalian embryonic heart and consequently hypoxia in the embryo. These drugs are highly teratogenic in experimental animals. There is evidence that drugs with IKr blockade as a side effect, for example phenytoin, may cause birth defects in the human by causing periods of embryonic hypoxia. The strongest evidence of hypoxia causing birth defects in the human comes from studies of fetuses lacking hemoglobin (Hb) F. These fetuses are thought to be hypoxic from about the middle of the first trimester and show a range of birth defects, particularly transverse limb reduction defects. | |||
(c) 2007 Wiley-Liss, Inc. | |||
PMID 17963271 | |||
Revision as of 02:53, 28 May 2012
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Cite this page: Hill, M.A. (2024, May 7) Embryology Abnormal Development - Environmental. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Talk:Abnormal_Development_-_Environmental |
2011
Low frequency vibrations disrupt left-right patterning in the Xenopus embryo
PLoS One. 2011;6(8):e23306. Epub 2011 Aug 3.
Vandenberg LN, Pennarola BW, Levin M. Source Center for Regenerative and Developmental Biology, Tufts University, Medford, Massachusetts, United States of America.
Abstract
The development of consistent left-right (LR) asymmetry across phyla is a fascinating question in biology. While many pharmacological and molecular approaches have been used to explore molecular mechanisms, it has proven difficult to exert precise temporal control over functional perturbations. Here, we took advantage of acoustical vibration to disrupt LR patterning in Xenopus embryos during tightly-circumscribed periods of development. Exposure to several low frequencies induced specific randomization of three internal organs (heterotaxia). Investigating one frequency (7 Hz), we found two discrete periods of sensitivity to vibration; during the first period, vibration affected the same LR pathway as nocodazole, while during the second period, vibration affected the integrity of the epithelial barrier; both are required for normal LR patterning. Our results indicate that low frequency vibrations disrupt two steps in the early LR pathway: the orientation of the LR axis with the other two axes, and the amplification/restriction of downstream LR signals to asymmetric organs.
PMID 21826245
Stockholm Convention on Persistent Organic Pollutants
http://chm.pops.int/default.aspx
2009
The Pine River statement: human health consequences of DDT use
Environ Health Perspect. 2009 Sep;117(9):1359-67. Epub 2009 May 4.
Eskenazi B, Chevrier J, Rosas LG, Anderson HA, Bornman MS, Bouwman H, Chen A, Cohn BA, de Jager C, Henshel DS, Leipzig F, Leipzig JS, Lorenz EC, Snedeker SM, Stapleton D.
School of Public Health, University of California-Berkeley, 2150 Shattuck Avenue, Berkeley, CA 94720, USA. eskenazi@berkeley.edu Abstract OBJECTIVES: Dichlorodiphenyltrichloroethane (DDT) was used worldwide until the 1970s, when concerns about its toxic effects, its environmental persistence, and its concentration in the food supply led to use restrictions and prohibitions. In 2001, more than 100 countries signed the Stockholm Convention on Persistent Organic Pollutants (POPs), committing to eliminate the use of 12 POPs of greatest concern. However, DDT use was allowed for disease vector control. In 2006, the World Health Organization and the U.S. Agency for International Development endorsed indoor DDT spraying to control malaria. To better inform current policy, we reviewed epidemiologic studies published from 2003 to 2008 that investigated the human health consequences of DDT and/or DDE (dichlorodiphenyldichloroethylene) exposure.
DATA SOURCES AND EXTRACTION: We conducted a PubMed search in October 2008 and retrieved 494 studies.
DATA SYNTHESIS: Use restrictions have been successful in lowering human exposure to DDT, but blood concentrations of DDT and DDE are high in countries where DDT is currently being used or was more recently restricted. The recent literature shows a growing body of evidence that exposure to DDT and its breakdown product DDE may be associated with adverse health outcomes such as breast cancer, diabetes, decreased semen quality, spontaneous abortion, and impaired neurodevelopment in children.
CONCLUSIONS: Although we provide evidence to suggest that DDT and DDE may pose a risk to human health, we also highlight the lack of knowledge about human exposure and health effects in communities where DDT is currently being sprayed for malaria control. We recommend research to address this gap and to develop safe and effective alternatives to DDT.
PMID 19750098
2007
The effect of hypoxia in development
Birth Defects Res C Embryo Today. 2007 Sep;81(3):215-28.
Webster WS, Abela D. Source Department of Anatomy and Histology, University of Sydney, Sydney, Australia. billweb@anatomy.usyd.edu.au
Abstract
There is increasing evidence that the oxygen supply to the human embryo in the first trimester is tightly controlled, suggesting that too much oxygen may interfere with development. The use of hypoxia probes in mammalian embryos during the organogenic period indicates that the embryo is normally in a state of partial hypoxia, and this may be essential to control cardiovascular development, perhaps under the control of hypoxia-inducible factor (HIF). A consequence of this state of partial hypoxia is that disturbances in the oxygen supply can more easily lead to a damaging degree of hypoxia. Experimental mammalian embryos show a surprising degree of resilience to hypoxia, with many organogenic stage embryos able to survive 30-60 min of anoxia. However, in some embryos this degree of hypoxia causes abnormal development, particularly transverse limb reduction defects. These abnormalities are preceded by hemorrhage/edema and tissue necrosis. Other parts of the embryo are also susceptible to this hypoxia-induced damage and include the genital tubercle, the developing nose, the tail, and the central nervous system. Other frequently observed defects in animal models of prenatal hypoxia include cleft lip, maxillary hypoplasia, and heart defects. Animal studies indicate that hypoxic episodes in the first trimester of human pregnancy could occur by temporary constriction of the uterine arteries. This could be a consequence of exposure to cocaine, misoprostol, or severe shock, and there is evidence that these exposures have resulted in hypoxia-related malformations in the human. Exposure to drugs that block the potassium current (IKr) can cause severe slowing and arrhythmia of the mammalian embryonic heart and consequently hypoxia in the embryo. These drugs are highly teratogenic in experimental animals. There is evidence that drugs with IKr blockade as a side effect, for example phenytoin, may cause birth defects in the human by causing periods of embryonic hypoxia. The strongest evidence of hypoxia causing birth defects in the human comes from studies of fetuses lacking hemoglobin (Hb) F. These fetuses are thought to be hypoxic from about the middle of the first trimester and show a range of birth defects, particularly transverse limb reduction defects. (c) 2007 Wiley-Liss, Inc.
PMID 17963271
