Development fetal/embryonic

McMahon I have a more general question about how the IGF system works. Your explanation for the absence of a tissue-specific effect of modulating IGF levels presupposes that there would be some data that suggest that IGF2 is acting locally. It is certainly expressed broadly throughout the whole embryo. An alternative hypothesis is that there are key places where it has been expressed during embryonic fetal development that are important and some places that are unimportant. What has been done in terms of tissue-specific removal or activation of this pathway ... 

Adverse Effects of Pesticides and Other Organic Contaminants on Embryonic/Fetal Development... 

Cosby NC, Dukelow WR. 1992. Toxicology of maternally ingested trichloroethylene (TCE) on embryonal and fetal development in mice and of TCE metabolites on in vitro fertilization. Fundam Appl Toxicol 19 268-274. 

Schwetz BA, Leong KJ, Gehring PJ. 1975. The effect of maternally inhaled trichloroethylene, perchloroethylene, methylchloroform, and methylene chloride on embryonal and fetal development in mice and rats. Toxicol Appl Pharmacol 32 84-96. 

Saillenfait AM, Bonnet P, de Ceaurriz J. 1989. Effects of inhalation exposure to carbon disulfide and its combination with hydrogen sulfide on embryonal and fetal development in rats. Toxicol Lett 48 57-66. 

McClain RM, Becker BA. 1972. Effects of organolead compounds on rat embryonic and fetal development. Toxicol Appl Pharmacol 21 265-274. 

Faust, N., et al. Different macrophage populations develop from embryonic/fetal and adult hematopoietic tissues, Exp. Hematol., 25, 432, 1997. 

Generally, it appears that effects of xenobiotics on organs or endpoints may be similar in children and adults, e.g., liver necrosis observed in adults will also be observed in children. As regards toxicodynamics, age-dependent differences are primarily related to the specific and unique effects that substances may have on the development of the embryo, fetus, and child in that the physiological development of the nervous, immune, and endocrine/reproductive systems continues until adolescence (12 to 18 years). Furthermore, receptors and other molecular targets for various xenobiotics are continuously developing during the embryonic, fetal, and infant periods. This may cause age-dependent differences in the outcome of receptor-xenobiotic interactions and even result in opposite effects of xenobiotics in infants and adults. The available data are insufficient to evaluate... 

Schwetz BA, Keeler PA, Gehring PJ The effect of purified and commercial grade pentachlorophenol on rat embryonal and fetal development. Toxicol Appl Pharmacol 28 151-161, 1974... 

Indications of embryo or fetal toxicity include increased incidence of embryonic or fetal resorptions, reduced or increased weight or size of the fetuses, and delayed fetal development and dysmorphogenesis. Any of these findings in the absence of maternal toxicity constitute evidence of selective developmental toxicity. Abortion in rabbits is a frequent consequence of maternal toxicity, but may also occur as the result of a compound-induced embryo-fetal mortality. 

The objectives of a teratology study (see Note 2) are to evaluate the effects of the test item on embryonic and fetal development when administered during the period of organogenesis, i.e., from uterine implantation to the closure of the hard palate (see Note 3)... 

Embryonic and fetal development of long-tailed macaques (cynomolgus monkeys)... 

CS167 Cozens, D. D., R. Clark, A. K. Palmer, N. Hardy, G. G. Nahas and D. J. Harvey. The effect of a crude marihuana extract on embryonic and fetal development of the rabbit. Adv Biosci Marihuana Biological Effects 1978 22 469-477. 

Lanoue, L., M.W. Taubeneck, J. Muniz, L.A. Hanna, P.L. Strong, F.J. Murray, RH. Nielsen, C.D. Hunt, and C.L. Keen. 1998. Assessing the effects of low boron diets on embryonic and fetal development in rodents using in vitro and in vivo model systems. Biol. Trace Elem. Res. 66 271-298. 

Chemicals that cross the placental barrier can act directly on the embryo/fetus, and it is likely that the majority of chemicals that cause developmental toxicity act in this way. Teratogenic chemicals are most likely to act directly on the fetus. Some chemicals cause maternal toxicity at high doses but interfere with embryonic or fetal development at lower doses, and these chemicals are of concern in reproductive toxicology. Many of the most widely recognized embiyotoxic or teratogenic chemicals are selectively active in this manner, and the dose that causes developmental toxicity can be much lower than the dose that is toxic to the mother (Khera, 1984). 

Schmid BP, Honegger P, Kucera P (1993) Embryonic and fetal development Fundamental research. Reprod Toxicol, 7(Suppl 1) 155-164. 

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