Towards new cholera prophylactics and treatment: Crystal structures of bacterial enterotoxins in complex with GM1 mimics

Cholera is a life-threatening disease in many countries, and new drugs are clearly needed. C-glycosidic antagonists may serve such a purpose. Here we report atomic-resolution crystal structures of three such compounds in complexes with the cholera toxin. The structures give unprecedented atomic details of the molecular interactions and show how the inhibitors efficiently block the GM1 binding site. These molecules are well suited for development into low-cost prophylactic drugs, due to their relatively easy synthesis and their resistance to glycolytic enzymes. One of the compounds links two toxin B-pentamers in the crystal structure, which may yield improved inhibition through the formation of toxin aggregates. These structures can spark the improved design of GM1 mimics, either alone or as multivalent inhibitors connecting multiple GM1-binding sites. Future developments may further include compounds that link the primary and secondary binding sites. Serving as decoys, receptor mimics may lessen symptoms while avoiding the use of antibiotics.

An experimental study on effects of monopolar diathermy on the bile ducts

OBJECTIVE

To study the effects of monopolar diathermy on the bile ducts in pigs.

DESIGN

Experimental study.

SETTING

University hospital, Norway.

MATERIAL

18 pigs.

INTERVENTIONS

Laparotomy, application of diathermy at standard sites along the cystic duct, the bile ducts, and a cystic duct containing a metal clip, 3 to 12 times of 5 seconds' duration at each site. Temperature was subsequently recorded at standard measurement points on the bile ducts. Twelve pigs were killed after three weeks for assessment of the bile ducts at necropsy.

MAIN OUTCOME MEASUREMENTS

Increase in temperature in the bile duct walls and late changes in the bile ducts.

RESULTS

Temperature increased by 4-6 degrees C during 6 of 330 diathermy applications along the cystic duct, by 4-18 degrees C in 8 of 126 applications along the common bile duct, and by 4-11 degrees C at the clip in 9 of 54 applications. There were no macroscopic or microscopic changes in the bile ducts.

CONCLUSION

Monopolar diathermy induced unexpected distant increases in the temperature of the bile duct walls and at a clip on the cystic duct probably because diathermy current energy was distributed along channels of high current conductivity.