Reproductive and Developmental Toxins

Catalog of Teratogenic Agents, 7th edition, Thomas H. Shepard, Johns Hopkins University Press, Baltimore, Maryland, 1992. This catalog is one of the best references available on the subject of reproductive and developmental toxins. 

The Laboratory Environment, R. Purchase, editor. Special Publication Number 136, Royal Society of Chemistry, Cambridge, United Kingdom, 1994. 

In addition to computerized MSDSs, a number of computer databases are available that supply data for 

The databases supplied by NLM are easy to use and relatively inexpensive. TOXLINE, the best source of information for most people, covers data published from 1981 to the present. For data published in the period from 1965 through 1980, TOXL1NE65, a back file of TOXLINE, is also available. The telephone number to call for information and instmctions on obtaining an NLM account is 1-800-638-8480. 

Other databases supplied by NLM are the Hazardous Substance Data Base (HSDB), the Registry of Toxic Effects of Chemical Substances (RTECS), and the Medical Literature Analysis and Retrieval System (MEDLARS). NLM also supplies other specialized databases called CANCERLIT, DART, GENETOX, IRIS, CCRIS, and CHEMID. 

---

Reproductive and developmental toxins are primarily a concern for livestock. 

Major Hazards Chronic toxin affecting the kidneys and central and peripheral nervous systems reproductive and developmental toxin. 

The building block for PC is BPA. This monomer exhibits toxic effects only at very high exposures and realistically, such high exposures are not possible under normal conditions indoors. BPA is not a carcinogen or a reproductive or developmental toxin. 

The principal study was well designed and well conducted, used a relevant exposure pathway, and examined the appropriate toxicological endpoints however, there was considerable variability in the blood ChE values of the exposed animals. The data base for GD lacks a toxicity study in a second species, chronic studies, as well as reproductive and developmental toxicity studies, including a multigenerational study. The unlikelihood that agent GD is a reproductive or developmental toxin reduces that significance of these data gaps. Overall confidence in the RfDe is low to medium. 

Evaluate type of toxicity. Use the above sources of information to determine the type of toxicity associated with each chemical involved in the proposed experiment. Are any of the chemicals to be used acutely toxic or corrosive Are any of the chemicals to be used irritants or sensitizers Will any select carcinogens or possibly carcinogenic substances be encountered For many substances, it will be necessary to consult the listings of carcinogens in this chapter (see Tables 3.4 and 3.5) to identify chemical similarities to known carcinogens. Are any chemicals involved in the proposed experiment suspected to be reproductive or developmental toxins or neurotoxins ... 

Dioxane shows carcinogenic effects in animal studies and is listed by lARC in Group 2B ("possible human carcinogen"). It is not classified as a "select carcinogen" according to the criteria of the OSHA Laboratory Standard. Prolonged or repeated exposure to this substance may result in liver and kidney injury. Dioxane has not been shown to be a reproductive or developmental toxin in humans. 

This product is a suspected carcinogen and endocrine toxicant. Classified as a possible developmental toxin. This substance is toxic to blood, the reproductive system, liver, and upper respiratory tract. 

Prenatal exposure of rats and rabbits to doses of methylacrylonitrile that did not induce toxicity in the adults also did not induce developmental toxicity in the fetus. Methylacrylonitrile was also determined not to be a selective reproductive toxin. In a continuous breeding study in rats, doses that caused decreases in epididymal sperm density of Fi... 

Both intensity and length of exposure play important roles in determining the extent of inhibition of NTE in lymphocytes 50% of preexposed values of NTE activity were obtained when measured 3 or 4 weeks after the beginning of DEF exposure. However, there is no direct evidence of a correlation between a high level of lymphocyte NTE inhibition and development of neuropathy in humans. Blood acetylcholinesterase and plasma butyrylcholinesterase levels remained unchanged during the study period. There is no available weight-of-the-evidence summary assessment for DEF as a developmental or reproductive toxin. 

Toxicity Ethylene oxide is a severe irritant to the eyes, skin, and respiratory tract and exhibits moderate acute toxicity by all routes of exposure. Symptoms of overexposure by inhalation may be delayed and can include nausea, vomiting, headache, drowsiness, and difficulty breathing. Ethylene oxide can cause serious bums to the skin, which may only appear after a delay of 1 to 5 hours. This substance may also be absorbed through the skin to cause the systemic effects listed above. Eye contact can result in severe bums. Ethylene oxide is not considered to have adequate warning properties. Ethylene oxide is listed by lARC in Group 2A ("probable human carcinogen") and is classified as a "select carcinogen" under the criteria of the OSHA Laboratory Standard. There is some evidence from animal studies that ethylene oxide may be a developmental and reproductive toxin in both males and females. Exposure to this substance may lead to sensitization. 

A wide range of adverse reproductive outcomes is possible as a result of exposure to reproductive toxins. Before conception, parental exposure may result in infertility or reduced fertility, unsuccessful fertilization or implantation, or fetal abnormality. Maternal exposure after conception may result in fetal death or congenital abnormalities. Examples of adverse outcomes of pregnancy can include spontaneous abortion, birth defects, perinatal death, altered sex ratio, low birth weight, developmental or behavioral disabilities, and exposure to potential carcinogens via the transplacental route (Table 12.8) (441). 

---