Day 036 - 13 Oct 94 - Page 39


     
     1        A.  Let me re-read that sentence and I will be glad to
     2        provide an interpretation, if that would be helpful.
     3        Yes.  What he is simply saying is that the status of the
     4        target organ -- by differentiation he means the degree to
     5        which the cells have duplicated and become breast cells,
     6        rather than a more immature type of cell -- that those
     7        will influence the effect of fat on carcinogenesis,
     8        presumably.  It is certainly in line with what virtually
     9        everyone would assume, is that carcinogens, in general,
    10        will exert different effects at different stages of life.
    11
    12   Q.   Can I read you the Conclusion?  That will be my last word
    13        before the break:  "We have documented that the following
    14        criteria must be satisfied in order for fat enhancement of
    15        mammary carcinogenesis in the experimental model to be
    16        expressed".  Then he repeats what we have already read in
    17        the abstract down to (c): "Previous history of pregnancy
    18        and lactation".   I will not read it again. "These
    19        findings convincingly indicate that there are limitations
    20        in extrapolating the results of fat and mammary
    21        carcinogenesis studies in rodents to the human experience
    22        of fat and breast cancer risk.  Animal models in nutrition
    23        and cancer research are useful to the extent that they
    24        allow investigators to confirm and extend each other's
    25        observations.  They also provide an ideal opportunity to
    26        design experiments so that independent variables can be
    27        evaluated one at a time.  Regardless of their deficiencies
    28        they are often perceived as the litmus test to validate
    29        certain correlative evidence from epidemiology studies.
    30        However, in reality, animal models are woefully inadequate
    31        to meet the challenge of offering definitive answers to a
    32        complicated area of research as in human nutrition and
    33        cancer aetiology.  Given the spectrum of confounders that
    34        are inherent in the association linking fat intake and
    35        human breast cancer, including differences in lifestyle,
    36        reproductive history, carcinogen exposure pattern, eating
    37        habits, complexity of the total diet, and the contribution
    38        of nonnutrients present in food, it is less than
    39        comforting to realise that so little information is
    40        available in the literature on the interactive effect of
    41        dietary fat with these other factors which clearly have a
    42        significant impact by themselves on the risk of breast
    43        cancer".
    44
    45        Now it is that last bit that I wish to know, whether you
    46        have any comment to make about it, Dr. Barnard?
    47        A.  Yes, I actually do have some comments on the
    48        Conclusion paragraph.
    49
    50   Q.   Yes.  Can I ask you one thing? 
    51        A.  Certainly. 
    52 
    53   Q.   Can you not write on the witness' documents simply because
    54        we have to use them again?
    55        A.  I was writing on my own pad.
    56
    57   MR. JUSTICE BELL:  He has got his own pad.
    58        A.  Forgive me.  I hope I have not made a strain mark on
    59        your document.
    60

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