Toxin Tolerances

A moment s insight is sometimes worth a life s experience. 

It is reasonable to surmise, therefore, that toxins to which BU have been exposed over many generations can be accommodated. It is new environmental toxins that should cause concern. 

There are some common foods that humans eat that are dangerous to their pets. These include 

There are a number of common chemicals that can poison your pets. These include 

And there are many common plants that can be poisonous, too, if eaten. These include 

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Karasow. Detoxification in relation to toxin tolerance in desert woodrats eating creosote bush. J Chem Ecol 2001 27(12) 559-2578. 

Scott, J.G., Liu, N.A., and Wen, Z. (1998). Insect cytochromes P450 diversity, insect resistance and tolerance to plant toxins. In D.R. Livingstone and J.J. Stegeman (Eds.) Forms and Function of Cytochrome P450, 147-156. 

Delayed action cytotoxins that inhibit the synthesis of nucleic acids. They are obtained from various molds/fungi (Aspergillus flavus, Aspergillus parasiticus). They are colorless to pale-yellow crystalline materials melting above 450°F. The "B" toxins fluoresce blue in the presence of UV light while the "G" toxins fluoresce green. They are only slightly soluble in water, but are soluble in methanol, acetone, and chloroform. Aqueous solutions are "probably stable" and "probably tolerant" to chlorine at purification concentrations. 

It is ironic that possibly the first animal model of relevance to immunotoxicology was reported by Portier and Richet in 1902 [45] in an attempt to induce tolerance to a sea anemone toxin, they accidentally produced a shock reaction in dogs. Since this was not the protective effect they had hoped to produce (phylaxis for protection in Greek), they named the reaction anaphylaxis [46], The irony, of course, is that this serious reaction, mediated by IgE in humans, has proven to be notoriously difficult to predict based on animal studies. This is no trivial issue, since anaphylaxis is a serious, life-threatening reaction associated with exposure to drugs, foods, cosmetic ingredients, and other exogenous substances [47],... 

Temporal and spatial shifts in the abundance of chemically undefended algae and cyanobacteria may leave grazers with few dietary options except to consume low-quality, chemically defended food items. While some herbivores may be able to either tolerate or inactivate these toxins (Samelle and Wilson 2005), species that lack tolerance may be faced with the dilemma of either remaining on a low-quality patch or migrating to a different patch, thus increasing their risk of predation by visual predators (Krivan and Vrkoc 2000). In systems that experience seasonal... 

Of the 14 volunteers for the Phase I study, 11 were given the transgenic potatoes containing the toxin as vaccine and three had ordinary potatoes. Blood and stool samples were collected from the volunteers to evaluate the vaccine s ability to stimulate both systemic and intestinal immune responses. Ten of the 11 volunteers who ingested the transgenic potatoes had fourfold rises in serum antibodies at some point after immunization, and six of the 11 developed fourfold rises in intestinal antibodies. The potatoes were well tolerated and no one experienced serious adverse effects. 

The Alternaria black spot fungi A. brassicae and A. brassicicola produce host-selective toxins as well. While A. brassicicola produces brassicicolin A (11) as the major host-selective phytotoxin [28], A. brassicae produces destruxin B (12) (Fig. 9.4) [29]. Consistent with the virulence of these phytopathogens, both brassicicolin A (11) and destruxin B (12) appeared to be more phytotoxic to the susceptible cruciferous species B.juncea than to the tolerant B. napus. 

The intraperitoneal LD50 values for fish, as for polkilotherms, are extremely low. This means that fish (with the exception perhaps of Fugu) are unable to tolerate even small amounts of the toxins in their bodies, and hence are unable to accumulate them. This important point will be discussed again below in connection with the effect of the toxins on the use of fish as food. 

Clonidine can be useful in treating the behavioral and attentional problems in Tourette s syndrome but is only 25% to 35% effective in controlling tics (Feck-man et ah, 1991). Two recent open trials found botu-linum toxin A (BTX) injections effective and well tolerated for treating tics in Tourette s syndrome (Awaad, 1999 Kwak et al., 2000). With no trials of any of these agents in subjects with MR, the clinician has no choice but to extrapolate from studies with typically developing children, while taking a very data-based approach to ensure that any treatments used are, in fact, effective. 

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