152 biopsies from the colon of healthy persons were incubated with sev
eral nutrition mediums in a microcalorimeter. The course of the heat-f
low rate was measured at 1 min interval and graphically displayed as a
function of time. For evaluation of the results, the maximum (P-max),
the mean values (P), and the area under the curve as a measure of the
total released energy (E-tot) of the power-time curves were determine
d. The mean enthalpy change of all samples over time was 3.9 mu W per
sample. Depending on incubation conditions, mean values ranged between
2.5 and 7.1 mu W, maximal values between 3.5 and 13.3 mu W. The areas
under the curve varied between 6.2 and 18.3 mJ. Our results also show
ed that bacterial growth can influence measured enthalpy changes if an
tibiotics are not present. Under identical incubation conditions, stee
l ampoules were better than glass ampoules with respect to methodic ar
tifacts. We conclude that microcalorimetric investigations on bioptic
material from colonic epithelium are possible. Interestingly, our meas
ured enthalpy changes were lower than those expected from the oxygen c
onsumption rates and other metabolic processes. The reason is yet to b
e explored. (C) 1997 Elsevier Science B.V.