Nucleation of Cholesterol Crystals

When supersaturated fresh gallbladder bile (or model bile) is centrifuged to remove solid crystalline and amorphous precipitates, and supernatant vesicles, and the resultant isotropic (one phase) solution maintained in a dust-free environment at 37 °C and examined daily by light microscopy, cholesterol crystals can be observed to precipitate. The time taken for these solid cholesterol 

The NT in normal (gallstone free) bile is long ( 10-14 days) while that in cholesterol gallstone carriers is pathologically rapid (often 1-2 days but always 5 days). However, in response to food, the gallbladder normally fills and empties several times per day. Therefore the NT measured in vitro does not relate to the residence time of bile within the gallbladder in vivo. For this reason, measurements of NT are of relative or comparative value - rather than a physiological measurement. 

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