there was a substantial escalation in the proportion of cells with less than 2n DNA information, in TNF a butyrate treated cultures, although not in those treated with butyrate alone. By 48 h, both butyrate alone and TNF a butyrate resulted in substantial increases in sub G1 cells, but, apoptotis was significantly higher in reaction to TNF a than to butyrate alone. TNF a apoptosis Caspase 8 is initiated as the proximal caspase in the apoptotic signalling stream activated in reaction to death receptor ligation. Recently, caspase 10 has been identified natural product libraries as playing the same position. The appearance of both caspase 8 and caspase 10 in CaCo 2 cells was shown by Western blotting. Therefore, the activity of certain inhibitors for both caspase 8 and caspase 10 were tested, alone and in combination. Experiments were carried out to look at the consequence of pre treatment with z IETD. Z and fmk AEVD. fmk, alone or in combination, on apoptosis assessed by TUNEL and nuclear morphology, 24 h after treatment of cells with TNF a butyrate. The number of cells exhibiting nuclear condensation and fragmentation alone, the number of TUNEL positive cells and the number of cells positive for both, were all notably decreased in TNF a cell cultures that had been pre treated with Immune system caspase inhibitors, in comparison to those that received no pre treatment. In cell cultures treated with TNF a, pre therapy with caspase inhibitors was observed to bring about the appearance of the significant number of cells that displayed unusual nuclear morphology, characterized by a shrivelled appearance and unfinished chromatin condensation. Because it was felt that they could represent cells that had withstood or were under-going caspase independent cell death, these abnormal cells were quantified. Cells with such morphology may be noticed in cultures treated with TNF a butyrate alone, nevertheless, the levels were dramatically greater within the cultures pre treated with either caspase inhibitor. Company treatment with AG-1478 structure both z IETD. fmk and zAEVD. fmk appeared to decrease the numbers of cells with atypical nuclear morphology, relative to levels seen following pre treatment of TNF a treated cultures with either chemical alone. Nevertheless, the amount of cells with irregular nuclear morphology seen following pretreatment with both inhibitors, and following treatment with TNF a, was still more than that seen following TNF a treatment with no present. Fig. 6D shows total cell death, as explained above, for the different treatment groups. Complete cell death in TNF a butyratetreated cultures was paid off by either caspase inhibitor, but this decline was only significant for z IEVD. fmk.