Consequences of exposures

In utero exposure of men to DES, a synthetic non-steroid estrogen, has been linked to increased incidence of meatal stenosis, epididymal cysts, testicular hypoplasia, cryptorchidism, microphallus, and sperm abnormalities (Henderson et al., 1976 Gill et al., 1977, 1979 Stillman, 1982). In females, adenosis, clear cell adenocarcinoma, and structural defects of the cervix, vagina, uterus, and fallopian tubes have been linked to in utero exposure to DES (Stillman, 1982). 

In utero exposure of male rats to dibutyl phthalate on gestational days 13-21 permanently alters the testis and produces foci of testicular dysgenesis (immature seminiferous tubules with undifferentiated Sertoli cells, Sertoli cell-only tubules, Leydig cell hyperplasia, morphologically distorted tubules, and the presence of abnormal germ cells), which persist in the adult animal (Fisher et al., 

Subsequent research demonstrated a coordinated, dose-dependent reduction in expression of key genes and proteins involved in cholesterol transport and steroidogenesis and a corresponding reduction in testosterone in the fetal testes (Lehmann et al., 

In humans, similar dysgenetic changes in the histology of the testis have been found in patients with testicular cancer, subfertility, or cryptorchidism (Sohval, 1954, 1956 Berthelsen Skakkebaek, 

Perinatal exposure of rats to butyl benzyl phthalate causes reduced anogenital distance, reduced testis weight, permanent nipples, hypospadias, cryptorchidism, and testicular malformations (Gray et al, 2000). Also, reduced daily sperm production has been linked to gestational and lactational exposure to butyl benzyl phthalate in rats (Sharpe et al., 1995). 

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QRA is fundamentally different from many other chemical engineering activities (e.g., chemistry, heat transfer, reaction kinetics) whose basic property data are theoretically deterministic. For example, the physical properties of a substance for a specific application can often be established experimentally. But some of the basic property data used to calculate risk estimates are probabilistic variables with no fixed values. Some of the key elements of risk, such as the statistically expected frequency of an accident and the statistically expected consequences of exposure to a toxic gas, must be determined using these probabilistic variables. QRA is an approach for estimating the risk of chemical operations using the probabilistic information. And it is a fundamentally different approach from those used in many other engineering activities because interpreting the results of a QRA requires an increased sensitivity to uncertainties that arise primarily from the probabilistic character of the data. 

Liver cancer can also be a consequence of exposure to hepatotoxic chemicals. Natural hepatocarcinogens include fungal aflatoxins. Synthetic hepato-carcinogens include nitrosoamines, certain chlorinated hydrocarbons, polychlorinated biphenyls (PCBs), chloroform, carbon tetrachloride, dimethyl-benzanthracene, and vinyl chloride.Table 5.15 lists the chemical compounds that induce liver cancer or cirrhosis in experimental animals or... 

The cancer risk equation described below estimates tlie incremental individual lifetime cancer risk for simultaneous exposure to several carcinogens and is based on EPA s risk assessment guidelines. Tliis equation represents an approximation of the precise equation for combining risks wliich accounts for tlie joint probabilities of tlie same individual developing cancer as a consequence of exposure to two or more carcinogens. The difference between tlie precise equation and tlie approximation described is negligible for total cancer risks less tlian 0.1. Thus, tlie simple additive equation is appropriate for most risk assessments. The cancer risk equation for multiple substances is given by ... 

A molecular variation of plasma membrane has been reported by Puccia et al. Reduction of total lipids (XL) content and significant variations of triglyceride (TG) and phospholipids (PL) fractions were observed as a consequence of exposure of C. intestinalis ovaries to TBTCl solutions. In particular, an evident TG decrease and a PL increase were observed, which probably provoked an increment in membrane fluidity, because of the high concentration of long chain fatty acids and, as a consequence, PL. This could be a cell-adaptive standing mechanism toward the pollutants, as observed in Saccharomyces cerevisiae. Also the increase in the content of the polyunsaturated fatty acids (PUPA), important in the synthesis of compounds such as prostaglandin which are present in the ovary in a stress situation, was probably a consequence of a defense mechanism to the stress provoked by the presence of TBTCl. 

More controversially, endocrine disruption as a consequence of exposure to the herbicide atrazine (2-chloro-4-ethylamine-6-isopropylamine-s-triazine), one of the most widely used herbicides in the world, has also been hypothesized to explain various adverse biological effects in frog populations in the United States. Exposure to atrazine in the laboratory at high concentrations, far exceeding those found in the natural environment, has been reported to induce external deformities in the anuran species Rana pipiens, Rana sylvatica, and Bufo americanus (Allran and Karasov 2001). Studies by Hayes et al. have suggested that atrazine can induce hermaphroditism in amphibians at environmentally relevant concentrations (Hayes et al. 2002 Hayes et al. 2003). Laboratory studies with atrazine also indicated the herbicide... 

Santos, E.M., Pauli, G.C., and Van Look, K.J.W. (2007). Gonadal transcriptome responses and physiological consequences of exposure to oestrogen in breeding zebrafish (Danio rerio). Aquatic Toxicology 83, 134—142. 

Human volunteers exposed to monomethylhydrazine at a concentration of 90 parts per million (ppm) for 10 min reported minor ocular and nasopharyngeal irritation as the only consequence of exposure (MacEwen et al. 1970). 

ERPGs are prepared by an industry task force and are published by the AIHA. Three concentration ranges are provided as a consequence of exposure to a specific substance ... 

Need for fireproofed structural steel Process 1. Consequences of exposure to-adjacent ... 

It is known that more fetal wastage than generally believed and many spontaneous abortions arise as a result of the presence of dominant lethal mutations in the developing embryo, many of which appear to be due to major chromosomal damage. In addition, impairment of male fertility may also be a consequence of exposure to mutagens. 

Evidence from the tobacco industry documents, from research studies that measure free-base directly in tobacco smoke particulate, and from examination of smokeless tobacco products, all show that the level of free-base nicotine as delivered to the tobacco user is a critical variable in the acceptance of tobacco products and their continued use. The physiological impact of the rapid delivery of nicotine in the free-base form is a critical determinant of continued nicotine-seeking behavior, with the unintended consequences of exposure to the other toxic components of tobacco smoke and smokeless tobacco. Evaluating total delivered nicotine alone is not sufficient to characterize product differences. To fully understand the influence nicotine has on the allure of these products, both total and free-nicotine levels must be measured. A comprehensive understanding of nicotine delivery is needed to help find effective means for breaking its addictive nature and, ultimately, in reducing the morbidity and mortality associated with tobacco use. The levels of free-base nicotine must be included as part of any effort to achieve a better understanding of how tobacco products themselves influence their continued use. 

Despite acknowledged successes, some outstanding issues still exist regarding the actual consequences of exposure to chemicals for humans and the environment, which have become more pressing ... 

Brain development occurs in a complex series of events regulated by cellular and environmental interactions (Levitt, 1998). Most abused substances readily cross the placenta. Many are concentrated in the amniotic fluid and metabolized less efficiently by the fetus, exacerbating the teratogenic consequences of exposure. The effects of prenatal exposure to drugs of abuse... 

Radiation-induced genomic instability and bystander effects are now well-established consequences of exposure of living cells to ionizing radiation. Cells not directly traversed by radiation may still exhibit radiation effects. This phenomenon, known as bystander effect, has become a major activity in radiation biology and in some cases has challenged the conventional wisdom. An example is the currently accepted models used for low-dose extrapolation of radiation risks. The currently used models assume that cells in an irradiated population respond individually rather than collectively. If bystander effects have implications for health risks estimates from exposure to ionizing radiation, then the question of whether this is a general phenomenon or solely a characteristic of a particular type of cell and the radiation under test becomes an important issue. 

Whaf are the consequences of exposure Basic epidemiological information has classic public-good attributes. Those who conduct basic research have difficulty restricting its consumption to those who contributed to the research costs. But once it is developed, private markets disseminate the knowledge through newspapers, magazines, and even television. 

So markets can disseminate information about the health consequences of exposure. But that information leaves undecided many basic value choices. 

These speculations lead me to argue that we should consider the possibility of a no-liability or buyer-beware liability regime. I believe the voluntary development and dissemination of information by firms about the consequences of exposure to their products would be much greater than it is today because consumers would realize... 

We have seen earlier in this chapter how the self-assembly of casein systems is sensitively affected by temperature. Another thermodynamic variable that can affect protein-protein interactions in aqueous media is the hydrostatic pressure. Static high-pressure treatment causes the disintegration of casein micelles due to the dismption of internal hydro-phobic interactions and the dissociation of colloidal calcium phosphate. This phenomenon has been used to modify the gelation ability of casein without acidification as a consequence of exposure of hydrophobic parts of the casein molecules into the aqueous medium from the interior of the native casein micelles (Dickinson, 2006). High-pressure treatment leads to a reduction in the casein concentration required for gelation under neutral conditions, especially in the presence of cosolutes such as sucrose (Abbasi and Dickinson, 2001, 2002, 2004 Keenan et al., 2001). 

Bekesi JG, Roboz J, Fischbein A, et al. 1985. Immunological, biochemical, and clinical consequences of exposure to polybrominated biphenyls. In Dean JH, Luster MI, Munson AE, et al., eds. Immunotoxicology and Immunopharmacology. New York, NY Raven Press, 393-406. 

McConnachie, PR. Zahalsky, A.C. (1991) Immunological consequences of exposure to pentachlorophenol. Arch, environ. Health. 46, 249-253... 

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