Permeability to [3H]mannitol increased 16-fold after exposure to 32 nM of toxin A and to 3 nM of toxin B when compared with controls (P < 0.05). Light and scanning electron microscopy after exposure to either toxin revealed patchy damage and exfoliation of superficial epithelial cells, while crypt epithelium remained intact. Fluorescent microscopy of phalloidin-stained sections showed that both toxins caused disruption and condensation of cellular F-actin. Our results demonstrate that the human colon is -10 times more sensitive to the damaging effects of toxin B than toxin A, suggesting that toxin B may be more important than toxin A in the pathogenesis of C. difficUe colitis in man. (J.

Intersphincteric resection is a valuable procedure for sphincter-saving rectal surgery. We showed that this technique has satisfactory long-term results in functional and oncologic respects. An important prerequisite is a careful preoperative evaluation of local tumor spread with rectal magnetic resonance imaging excluding infiltration of the external sphincter.

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