In situ measurements of the physical characteristics of Titan's environment.

On the basis of previous ground-based and fly-by information, we knew that Titan's atmosphere was mainly nitrogen, with some methane, but its temperature and pressure profiles were poorly constrained because of uncertainties in the detailed composition. The extent of atmospheric electricity ('lightning') was also hitherto unknown. Here we report the temperature and density profiles, as determined by the Huygens Atmospheric Structure Instrument (HASI), from an altitude of 1,400 km down to the surface.

Diagnostic value of serum bile acids and routine liver function tests in hepatobiliary diseases. Sensitivity, specificity, and predictive value.

Total serum bile acids measured by enzymatic fluorometry and routine liver function tests were determined in a large population including 97 healthy subjects, 138 patients free of hepatobiliary diseases but affected by other diseases, and 344 patients with mild or severe hepatobiliary diseases. In order to define the diagnostic value and some operational characteristics of serum bile acids, sensitivity, specificity, and several predictive value tables for increasing cutoff levels of serum bile acids were calculated by means of a computer program. Serum bile acids and aspartate aminotransferase were found to be similar in sensitivity, specificity, and predictive value.

Meal stimulated response of serum bile acids levels in normal and altered bile acids enterohepatic circulation.

Sequential measurement of postprandial serum levels of bile acids was carried out in ten healthy controls and in four patients with different impairment of bile acids enterohepatic circulation. An enzymathic fluormetric method was used for SBA analysis. The peak of increase above fasting baseline in normal subjects was 11.