Thursday, October 6, 2011

Mechanisms which could be activating meso.

Layard and Stanton hypothesized in 1977/78 that chemical effects linked to cancer (mesothelioma) are not initiated by the toxicity of fibrous materials, that's any trigger-effects of asbestos must presumably be physical. They presume:
 
  • (A) mechanical damage
  • (B) unwanted signal channels (a property for thin transparent fibres) which might disrupt normal cell activity, especially mitosis.

(A) Mechanical Damage. There is experimental evidence that very slim fibers (<60 nm, <0.06 μm in width) do tangle destructively with chromosomes (being comparably sized ). It is quite clear that it's likely to cause the sort of mitosis disruption expected in cancer (mesothelioma).


(B) Unwanted Signal Channels. This presume has recently been explored theoretically, but unfortunately not yet experimentally. The theory claims that this effect would only be feasible for asbestos fibers >100 nm in width ( or >150 nm in the chrysotile case), suggesting that we should be on the look-out for a possible mixture of different mechanisms for the various fiber-diameter-ranges.



One popular idea of the causal chain is


             (1) Asbestos fiber → → (3) inflammation → → (4) other pathology


    Although this may be true, it does't explain → → (2) the actual trigger.

    "What is the physical characteristic of asbestos which initiates such an inflammation?"
    After all, inflammation is commonly seen as caused by chemical-based processes: immunological and/or bacterial. So inflammation may well be part of the causal chain, but not a crucial first step.

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