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“endocrine disruptors” “endocrine mimics” “environmental estrogens” “hormone mimics” PowerPoint Presentation
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“endocrine disruptors” “endocrine mimics” “environmental estrogens” “hormone mimics”

“endocrine disruptors” “endocrine mimics” “environmental estrogens” “hormone mimics”

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“endocrine disruptors” “endocrine mimics” “environmental estrogens” “hormone mimics”

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  1. “endocrine disruptors” “endocrine mimics” “environmental estrogens” “hormone mimics” “environmental hormones” these terms all basically refer to the same thing: that human-made chemicals that accumulate in the environment can enhance, block, or otherwise disrupt reproductive hormones in animals

  2. Greenlee, AR, TE Arbuckle and P-H Chyou. 2003. Risk factors for female infertility in an agricultural region. Epidemiology 14:429-436. “There was an association of female infertility [12 months of unprotected intercourse without conceiving a pregnancy ending in live birth]with...mixing and applying herbicides or exposure to fungicides [within 2 years before] attempting conception. [Previous studies showed that] rodents [given] triazine herbicides (atrazine, simazine, propazine and degradants) [showed]...endocrine disruption (eg, [reduced] lutenizing hormone surges, variable [reproductive] cycle length, poor pregnancy maintenance, and delayed [puberty]. Evidence suggests these [effects] may be related to pesticide interference of the hypothalamic-pituitary-gonadal [hormone] axis.”

  3. Salam, MT, Y-F Li, B Langholz and FD Gilliland. 2003. Early Life Environmental Risk Factors for Asthma: Findings from the Children's Health Study. Environmental Health Perspectives. Online 9 December 2003. children younger than 1 years old exposed to herbicides were ten times more likely to develop asthma than unexposed (control) children. This study also showed increased risk of asthma in children exposed to pesticides, as well as infants who went to day care before 4 months of age (?!). exposure to herbicides and pesticides after 1 years of age did not increase asthma risk

  4. Schecter, A, M Pavuk, O Päpke, JJ Ryan, L Birnbaum and R Rosen 2003. Polybrominated diphenyl ethers (PBDEs) in U.S. mothers’ milk. Environmental Health Perspectives (available at PDBEs are commonly used as “flame retardants”: they prevent things from catching on fire The same week this study came out, ex-Gov. Gray Davis signed a law banning PDBEs in California...staring in 2008 PDBEs have not been definitely linked to any health problems in humans, but studies in rodents have shown interference with thyroid hormone and associated defects in brain development

  5. other potential endocrine disruptors.... phthalates – chemicals used as plastic softeners among other things, including cosmetics and toys – rodent studies show inhibition of male hormones and effects on male fertility bisphenol A – chemical used in polycarbonate plastic – causes problems in the cell division processes in mouse eggs, also interferes with estrogen PCBs – were used as a coolant/lubricant in a lot of electrical equipment, now banned in the US - interferes with estrogens, androgens (e.g. testosterone) and thyroid hormones, associated with many potential problems, including reproductive defects, cancer, and a host of other things dioxins – released by paper mills and waste burning incinerators; also a by-product of “agent orange” (still high in food supplies in Vietnam) – linked to immune system suppression, reproductive defects, alteration in sex ratios and other problems NPEs (nonylphenol ethoxylates) – “super-strength” cleaners, some detergents, some pesticides; also produced in several steps during the drilling for and production of gasoline – some NPEs are used in human spermicides! Fish exposed to NPEs are gender-benders

  6. more good news about beef....dioxin exposure!! (based on average US diet) EPA Dioxin Reassessment Summary 4/94

  7. EPA Dioxin Reassessment 2000

  8. (DIOXINS) EPA Dioxin Reassessment 2000

  9. “blastocyst” stage embryo is implanting in the uterus wall sperm and egg nuclei are about to fuse! embryo is undergoing early cell divisions (“cleavage”) days after ovulation 1 day 1.5 - 3 days 5 – 6 days

  10. growth of the placenta following implantation of the embryo in the uterus (days 8 to 12 or so after ovulation) chorion (yellow) amniotic cavity placenta embryo (brown) uterus wall

  11. different molecules are dealt with differently by the placenta… immune proteins glucose, oxygen some hormones (most large molecules) maternal blood side fetal blood side

  12. heart begins to beat (but circulatory system is still incomplete); brain has closed up that’s the precursor of the spinal chord we’re segmented! (like a bug) days after ovulation 16 days 21 - 23 days 23 – 25 days