Galactose elimination kinetics in perfused rat liver after two thirds hepatectomy

Liver regeneration and restoration of liver function after partial hepatectomy in patients with liver tumors

Liver regeneration and restoration of liver function were studied in six patients who underwent partial hepatectomy with removal of 30-70% of the liver. Liver volume and liver regeneration were studied by single-photon computed tomography (SPECT), using 99mTc-colloid as tracer. The method was assessed in 11 patients by comparing the pre- and post-operative volume measurements with the volume of the resected liver mass. The correlation coefficient between these methods was 0.899 (P less than 0.01). Liver function was determined by measuring the galactose elimination capacity and the caffeine clearance. After a postoperative follow-up period of 50 days the liver had regenerated maximally to a volume of 75 +/- 2% of the preoperative liver mass. Maximal restoration of liver function was achieved 120 days after operation and amounted to 75 +/- 10% for the caffeine clearance and to 100 +/- 25% for the galactose elimination capacity. This study shows that SPECT is a useful method for assessing liver regeneration in patients after partial hepatectomy. Our study furthermore shows that caffeine clearance correlates well with total liver volume, whereas the galactose elimination capacity overestimates total liver volume after partial hepatectomy.

Isolated perfused liver technology for studying metabolic and toxicological problems

The isolated perfused liver system is a versatile model for investigating the effects and mechanisms of action of hepatotoxins and the metabolism of endogenous and exogenous compounds. The interpretation of metabolic data and apparent toxic events is dependent upon the viability and reproducibility of the model. In this study, a new approach has been undertaken to assess the viability of isolated liver preparations. This has involved the continuous monitoring of multistage processes namely, the synthesis and secretion of radiolabelled proteins, glycoproteins and lipoproteins on the one hand and the uptake of macromolecules by receptor-mediated endocytosis on the other. The consistency of these complex integrated processes from one liver to another and in particular the steady-state rate of production of radiolabelled macromolecules over 6h perfusion periods suggests that this model can be used with confidence for metabolic/toxicological investigations. The selectivity of the responses to chemical challenge(s) shows that this system can be exploited for (a) screening potential hepatotoxins; (b) identifying areas of metabolism which are affected and (c) advancing basic knowledge of liver biochemistry.

Evaluation of liver volume and liver function following hepatic resection in man

In a longitudinal study liver volume and liver function were measured in a series of 12 patients undergoing partial liver resection for focal hepatic lesions. Ultrasonography revealed that liver volume, reduced by about 50% by the resection, progressively increased, and 6 months after surgery it returned to nearly normal values. A variable reduction in routine liver function tests was observed, possibly reflecting the influence of the different reserve synthetic capacity of the liver and, in the early postoperative phase, plasma half-life of liver products and blood loss or changes in plasma volume. The galactose elimination capacity was only marginally reduced in the early period (from a pre-surgery value of 2.49 +/- SE 0.21 mmol/min to 2.31 +/- 0.14 after 7 days; p = ns) and reached a nadir at 14 days (1.97 +/- 0.16; p less than 0.001). When expressed per unit of liver volume, the galactose elimination (22 +/- 2 mumol/min per unit before resection) progressively decreased during the regeneration phase from 36 +/- 4 at 14 days to 26 +/- 3 at 6 months (P vs 14-day: less than 0.01). At 6 months both galactose elimination and galactose elimination per unit of liver volume were no longer different from baseline values. Our data show that, following hepatic resection, both liver volume and liver function increase and progressively return to nearly normal values. In agreement with data obtained in animal studies, it appears that the metabolic activity of the remaining parenchyma is increased in the early postoperative phase, and it slows down in the course of regeneration.

Acetaminophen metabolism by the perfused rat liver twelve hours after acetaminophen overdose

The effect of a toxic dose of acetaminophen on the hepatic conjugations of acetaminophen was studied in single pass perfused livers from rats given acetaminophen overdose 12 hr prior to perfusion and from control rats. Four different acetaminophen concentrations (0.1-6 mmol/1) were used in each perfusion. Glucuronidation of acetaminophen was increased and sulfation of acetaminophen occurred at an unchanged rate in acetaminophen damaged livers as compared to control livers. Hepatic glutathione concentrations declined to about 0.4 mumol/g liver during perfusion, possibly due to excretion of glutathione to perfusion medium, but in spite of this the formation of glutathione conjugates was increased with acetaminophen concentrations increasing up to about 5 mmol. We conclude that decreased sulfation, glucuronidation and glutathione conjugation in the liver is not present in the early development of acetaminophen-induced hepatic damage.