Teratogenic human fetus

Zinc was confirmed as essential for humans in 1936 and deficiency symptoms were reported in l%l. The size of ihe human fetus is correlated with zinc concentration in the amnintic fluid and habitual low zinc intake in the pregnant female is thought to he related (o several congenital anomalies in humans. Low zinc intakes result in hypogonadism, dwarfism. mental retardation, low serum and red blood cell zinc in humans and animals, and retarded growth and teratogenic effects on the nervous system in rats. 

While the literature abounds with reports of the undesirable reproductive consequences of DDT exposure at all levels of animal systems, little human research in this area has made its way into the open literature. Shepard s Catalog of Teratogenic Agents (ref. 86) and Nisbet-Karch (ref. 47) each list only the work of O Leary et al. (ref. 87), correlating spontaneous abortion in human females with human pesticide residues, and prematurity of human fetuses with DDE levels found in fetal whole blood. Perhaps the more serious risk with DDT and DDE is the significant presence of these two along with other... 

Of the newer anticonvulsants, lamotrigine, gabapentin, tiagabine, and vigabatrin have little or no teratogenic potential in animals, whereas oxcarbazepine and topira-mate are teratogenic in rodents. However, animal studies are not necessarily apphcable to humans and chnical data are stiU insufficient to assess the effects of newer drugs on the development of the human fetus (153). 

There are no reports documenting excess chromium as a teratogen in the human fetus. 

Precautions Highly toxic to earthworms and some fish. Poison by swallowing. Mildly toxic by breathing. An animal teratogen (abnormal fetus development). Caused reproductive effects in animal studies (infertility or sterility or birth defects). A human mutagen (changes inherited characteristics). A skin irritant. EPA was ordered by courts to revoke approval as food additive in 1992. 

Precautions A definite carcinogen (causes cancer). An animal teratogen (abnormal fetus development). Moderately toxic to humans by swallowing. Various effects on the body by swallowing include liver changes, respiratory effects, and constipation. An eye irritant. 

TenitogM—A teratogen is a substance that has an adverse effect on a human fetus. It can cause the fetus to have deformities from the normal. A good example is a two-headed calf. 

Teratogen—a substance that is suspected to have an adverse effect on the development of a human fetus... 

Experimental studies have shown that cadmium can induce metallothionein synthesis in the placenta, particularly in trophoblasts. Metallothionein in the placenta binds the essential trace metals, zinc and copper. The mechanism whereby essential metals are preferentially transported to the fetus and cadmium retained is not known. Experimental studies have shown that exposure of pregnant animals to high levels of cadmium early in pregnancy is teratogenic. Human studies suggest maternal cadmium exposure may reduce fetal birth weight and that this may be an indirect effect of zinc deprivation that occurs with cadmium exposure. 

Information on the transplacental transfer of americium in humans is not available directly, but the information from experiments with americium and other actinides has been used to derive biokinetic models and perform dosimetric models for the human (NCRP 1998 NRC 1996 Sikov and Kelman 1989). Studies in animals that received parenteral injections of americium have shown that absorbed americium is transferred to the fetus (Hisamatsu and Takizawa 1983 Paquet et al. 1998 Sasser at al. 1986 Schoeters et al. 1990 Weiss et al. 1980) (see Section 3.4.2.1). Limited reports indicate that241 Am may induce fetal death and teratogenic effects in rodents (Moskalev et al. 1969 Rommerein and Sikov 1986). 

Grossly elevated concentrations of dissolved copper produce teratogenicity in fish embryos. A significant number of malformed fish larvae came from eggs treated with 500 pg Cu/L (Birge and Black 1979). In studies with laboratory animals and elevated concentrations of copper salts, copper penetrates the placental barrier into the fetus intramuscular injection of 4 mg Cu/kg BW early in pregnancy adversely affects fetal central nervous system development (Aaseth and Norseth 1986). In humans, no definitive data are available on whether copper can cause birth defects however, incubation of human spermatozoa with metallic copper results in loss of sperm motility (Aaseth and Norseth 1986). 

---