Toxic factors

Neither the mechanism by which benzene damages bone marrow nor its role in the leukemia process are well understood. It is generally beheved that the toxic factor(s) is a metaboHte of benzene (107). Benzene is oxidized in the fiver to phenol [108-95-2] as the primary metabolite with hydroquinone [123-31-9] catechol [120-80-9] muconic acid [505-70-4] and 1,2,4-trihydroxybenzene [533-73-3] as significant secondary metabolites (108). Although the identity of the actual toxic metabolite or combination of metabolites responsible for the hematological abnormalities is not known, evidence suggests that benzene oxide, hydroquinone, benzoquinone, or muconic acid derivatives are possibly the ultimate carcinogenic species (96,103,107—112). 

Environmental. The toxicity of cyanide in the aquatic environment or natural waters is a result of free cyanide, ie, as HCN and CN . These forms, rather than complexed forms such as iron cyanides, determine the lethal toxicity to fish. Complexed cyanides may revert to free cyanide under uv radiation, but the rate is too slow to be a significant toxicity factor. Much work has been done to estabhsh stream and effluent limits for cyanide to avoid harmful effects on aquatic life. Fish are extremely sensitive to cyanide, and the many tests indicate that a free cyanide stream concentration of 0.05 mg/L is acceptable (46), but some species are sensitive to even lower concentrations. 

In these waters there is a severe limitation on inhibitor choice because of the potability and toxicity factors. As pointed out by Hatch , the possibilities... 

Aquatic Toxicity. This is the sum of the toxicity factor of a particular emission multiplied by the amount. Since the factors have only been... 

GUPTA Y p (1987) Anti-nutritional and toxic factors in food legumes a review. Plant Foods Hum Nutr. 37 201-28. 

Etiology. Most cases of PD are sporadic and appear to arise from a combination of genetic predisposition and environmental or toxic factors. Purely genetic forms of the disease probably account for less than 10% of cases, but the risk of family members of an affected patient to develop PD is significantly increased even in sporadic PD. 

The standard curve will in some instances not follow a straight course or will have a wrong slope. If the slope is too steep, i.e., if the double concentration gives more than double a value of optical density, one will suspect the presence of an inhibitor or toxic factor, relatively more effective at lower concentrations, or of a stimulating factor relatively more effective at higher concentrations. In the case of strongly colored samples, optical compensation can be achieved in the reading of the... 

The acute exposure guidelines discussed in Chapter 4 have a similar basis to the toxicity factors listed here. 

Primor, N., Parness, J., and Zlotkin, E. (1978). Paradaxin the toxic factor from the skin secretion of the flatfish Paradachirus marmoratus (Soleidae). In Toxins Animals, Plants and Microbial, ed. P. Rosenberg. Oxford Pergamon Press. 

According to Renwick, the nature of toxicity factor was not always applied to the NOAEL for the toxicity of concern, for example ... 

Tiller JR, Schilling RS, Morris JM Occupational toxic factor in mortality from coronary heart disease. BrMedJ 4 407M-11, 1968... 

Iriarte and Barnes (29) showed that cystine destruction by heat made this amino acidTirst limiting for the rat. However, cystine supplementation did not return the nutritional value to the optimum level. These workers were unable to determine the second limiting amino acid and could not rule out the possible development of a toxicity factor. Taira (30) determined that only cystine was destroyed under heating conditions commonly... 

In direct cell implantation, human cells are required but supplies are limited. Production of hepatocytes from pediatric patients has been reported and techniques for preservation are improving. yHfQ characterization of human hepatocytes will aid the development of improved cell-based therapies. The primary safety concern with the use of cell lines, especially implanted cells, is the transmission of toxic factors to the host. 

PROTECTION BY SELEGILINE OF DOPAMINERGIC NEURONS IN CULTURE FROM TOXIC FACTORS... 

Therefore, toxicity tests, or in other words bioassays, can supply information on the total load of an investigated sample in a diverse (in terms of type and quantity) mixture of pollutants, which allows for the possibility of their interactions.8-12 Bioassays are based on the use of particularly sensitive species (bioindicators), which are characterized by their quick reaction to changes in their environment. This results from their relatively low ability to maintain a stable state of equilibrium, that is, from their narrow range of tolerance to specific toxic factors. Such organisms show a special ability to accumulate pollutants.13 Hence, they can work as so-called Biological Early Warning... 

A. V. Folia, Food additives as toxic factors in childhood. Clin. Int. Bare. 26(9) 396-403, 1976. 

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