ABSTRACT
Fluorescence anisotropy decays of the 7-diethylamino-4-methylcoumarin C1 in various polar solvents of different viscosities and hydrogen bond donor/acceptor character have been recorded by means of the fluorescence upconversion and time-correlated single photon counting techniques. The resulting characteristic times for the rotational diffusion fall into two classes with regards to the viscosity-dependency: n-alcohols and "other" solvents. This deviation from the simple Stokes-Einstein-Debye model may be interpreted in terms of rotation of the coumarin molecule under two different hydrodynamic boundary-conditions ("stick" or "slip") in the two solvent classes. Possible explanations for this behaviour are discussed, and in particular solvent attachment and additional dielectric friction. Both these phenomena may in fact, under certain conditions, explain our findings. Our opinion, however, is that the dielectric friction model offers a more realistic picture of the additional rotational friction experienced by C1 in n-alcohols.
ABSTRACT
Ascites is a complication of chronic liver disease that is associated with decreased survival. The purpose of the present study was to identify some prognostic factors easily obtainable by the clinician in a large group of cirrhotic patients with ascites, possibly useful for first screening of outpatients as candidates for liver transplantation. We studied 134 ambulatory patients with cirrhosis who came to our outpatient clinic between July 1983 and March 1989 because of an episode of ascites. These patients were then followed up for an average period of 31 +/- 23 months and survival was determined. Thirty-one variables determined at the time of inclusion were analyzed with a Cox proportional hazards model to identify predictors of mortality. Cumulative mortality as of June 30, 1991, was 59%. Factors independently correlated with death were: refractory ascites (relative risk, 4.78), low albumin levels (3.77), high Child-Pugh score (3.31), encephalopathy (2.71), high bilirubin levels (2.03), high gamma-glutamyl-transferase levels (1.87), and old age (1.57). The results show that 1) the occurrence of refractory ascites has a prognostic value superior to those of other variables, and 2) simple clinical and biochemical parameters, most of them components of the Child-Pugh score, are useful for a first screening of ascitic cirrhotic patients as candidates for liver transplantation.
