Colonic dialysis

It has been demonstrated using sheep that the colon is permeable to urea. Of nine sheep subjected to bilateral nephrectomy, six had an increased life span when dialysed via an isolated loop of colon compared to the other three used as controls. Further experiments were carried out on urea-loaded sheep and in sheep made chronically uraemic by an immunological technique which confirmed that urea could be dialysed across the colon at lower blood urea levels as well.