Cross-circulation in experimental hepatic failure in the pig

In experimental liver failure (pigs with totally devascularized liver) the effect of different types of extracorporeal hepatic assistance was evaluated. Group I (N = 6) were untreated controls, Group II (N = 6), simple cross-circulation, Group III (N = 6), cross-circulation with inflow in the donor directly into the portal vein and Group IV (N = 4), cross-perfusion with isolated perfused liver. The cross-circulation was started 20 h after devascularization. There was no change in survival time. Bilirubin was decreased by a factor of 2 and the prothrombin index increased by a factor of 2 after initiation of the cross-circulation due to the dilution. In contrast to this, ammonia was unchanged. During the perfusion no significant changes were found. In Group V (N = 4), extended cross-perfusion with isolated perfused liver for 20 h, starting just after exclusion of liver function in the recipient and with a new liver in the perfusion system every 6th hour, the survival time was significantly increased. Furthermore, changes in the biochemical variables were prevented. It is concluded that with a supply of quantitatively sufficient hepatic assistance it is possible to extend the survival time in experimental liver failure.

Cerebral metabolism during cross-circulation in experimental hepatic failure in the pig

The effect of hepatic assistance on cerebral metabolism was evaluated in a series using cross-circulation, anticipating increased efficiency of hepatic support. The experimental model for liver failure was pigs with totally devascularized liver. Cross-circulation with a normal sibling pig, cross-circulation with inflow in the donor directly into the portal vein and cross-perfusion with isolated perfused liver starting 20 h after elimination of liver function in the recipient and lasting for 3 h did not increase survival. Before cross-circulation in these three groups, the cerebral flow and oxygen uptake were decreased; during the cross-circulation a significant but temporary increase was found. In experiments with early and prolonged perfusion with isolated perfused liver no changes in cerebral flow, oxygen or glucose uptake were found, and these variables were still normal 6 h after termination of the perfusion. The survival time was significantly increased. In the control group a significant rise in blood and CSF ammonia was found with a mean CSF/blood ratio of 0.92. After cross-circulation, the CSF/blood ratio was 0.52 and 0.62, respectively, indicating a proportionally greater elimination of ammonia from the cerebrospinal fluid than from the blood. Cross-circulation did not significantly change the alpha-ketoglutarate, glutamate or glutamine CSF concentrations. After prolonged cross-perfusion, the ammonia blood/CSF ratio was 0.24. It is concluded that by extended extracorporeal hepatic assistance it is possible to increase survival and to prevent changes in cerebral metabolism and ammonia accumulating in the cerebrospinal fluid.

The effect of physiological temperature changes on the galactose elimination capacity of the isolated perfused pig liver

The effect of temperature changes (36-40 degrees C) on the liver function was studied in the isolated perfused pig liver. When compared with control studies no effect was observed on lactate, glucose, bile flow, ATP and energy charge, and the recovery after the changes in temperature was complete. The only significant changes observed regarded the hepatic oxygen uptake and galactose elimination capacity. The increase of 1 degree C resulted in an increase in galactose elimination of 6%, corresponding to a Q10 of 1.98 (SEM 0.12) with an energy of activation of 48 kJ/mol (SEM 4.7). Oxygen uptake was linearly related to galactose elimination (1.75 mol for 1 mole change in galactose elimination). These results indicate that circulatory changes are unimportant within physiological temperature changes. It is concluded that temperature effects on galactose elimination are too small to warrant a correction when used as a clinical test of quantitative liver function.

Cerebral flow and metabolism in experimental liver failure. A comparison between hepatectomy and total hepatic devascularization in pigs

To evaluate the influence of necrotic liver tissue on the cerebral metabolism and cerebral function in acute liver failure, comparison was made between hepatectomy and total liver devascularization in pigs. In both groups the cerebral blood flow and glucose uptake were significantly decreased. The cerebral oxygen uptake was not reduced. The EEG frequency gradually fell from 12-14 Hz to 1-2 Hz, with intermittent and finally persistent flattening of cortical activity. The visual evoked potentials were unchanged throughout the observation period. The vascular autoregulation and the CO2-reactivity of cerebral circulation disappeared, indicating complete vasoparalysis. As no difference was found between the two groups, it is concluded that the encephalopathy was not due to intoxication from necrotic liver tissue in the abdominal cavity, but to deprivation of liver function.

Effect of short lasting hypoxia on the metabolic function of the perfused pig liver. Comparison of ischaemic and hypoxaemic hypoxia

The effects of hypoxaemia and ischaemia were compared in the perfused pig liver. Decreased hepatic oxygen uptake, galactose elimination, ATP phosphorylation and increased lactate output occurred when the oxygen supply was diminished below 55% of the mean of controls. Below the control limits for oxygen uptake and oxidative phosphorylation, the change in the above variables were correlated to the degree of hypoxia, with no quantitative differences regarding ischaemic or hypoxaemic hypoxia. Galactose elimination was correlated to the ATP concentration (r = 0.81). After 80 min of hypoxia almost complete recovery was seen. It can be inferred from the data that other factors than oxygen diffusion into the liver cells may limit oxidative metabolism. Long and severe hypoxia may be required before irreversible cellular damage occurs in the liver.

Antiestrogen therapy in pancreatic carcinoma: a preliminary report

Ten patients with unresected pancreatic carcinoma, treated with Nolvadex 10 mg 3 times a day were compared to a historic untreated control group. The median survival was 7 months in the treated group compared to 3 months in the untreated. In the control group all patients died within the first 9 months, in the treated group 40% of the patients were still alive after 14 months.

Diagnostic accuracy of endoscopic gastrobiopsy in carcinoma of the stomach. A histopathological review of 101 cases

101 gastrobioptic series from 93 consecutive patients with a final diagnosis of carcinoma of the stomach were reviewed. 20 false negative cases were found. Of these, ten cases were missed because of erroneous histopathological interpretation, two because of too few sections, and eight because carcinoma was not represented in the biopsies. The frequency of false negatives was slightly larger in ulcerating carcinomas than in polypoid and diffusely spreading carcinomas, mainly due to seven cases of ulcerating carcinoma being missed by the pathologist. There was no correlation between false negatives and histological type. The rate of false negatives was significantly higher in cases, where the number of biopsies taken was below seven. The rate of histopathological misinterpretations was significantly higher in cases, where the number of actually positive biopsies was below four. Attempts to increase the positive yield should be based on not only an evaluation of the biopsy technique, but also an analysis of the histopathological method and interpretation.

Renal and cerebral blood flow in experimental liver failure in the pig

The renal and cerebral blood flow was measured in six pigs after total devascularization of the liver. The animals died 21 to 26 h after the operation, with biochemical and electroencephalographic changes compatible with liver failure. The renal blood flow increased slightly, from 2.12 to 2.61 ml.g-1.min-1, throughout the period of observation but did not differ significantly from that of the controls. Conversely, the cerebral blood flow decreased 38%, from 1.30 to 0.80 ml.g-1.min-1, p less than 0.05. The results failed to confirm a simultaneous decrease in cerebral and renal blood flow due to false neurotransmitters in liver failure, as previously suggested. The results do not support the suggested hypothesis that a substance produced by the liver is essential for renal function and perfusion, nor can they confirm that vasoactive material from the gut is responsible for the renal hypoperfusion in liver failure. The absence of renal hypoperfusion in the present preparation might be due to the exclusion of the failing liver from the circulation, giving indirect evidence to the theory that the vasoactive agent(s) responsible for the renal hypoperfusion in liver failure originates in the failing liver itself.

Kinetics of ethanol inhibition of galactose elimination in perfused pig liver

The effect of ethanol (5--25 mM) on the galactose elimination kinetics in the intact liver was studied in the isolated perfused pig liver, using the steady-state infusion technique. Ethanol reduced galactose-Vmax on average to 0.07 mmol/min kg liver in six experiments from 0.43 mmol/min kg obtained in control experiments without ethanol. Also Km was significantly reduced from 0.23 mmol/l plasma water to 0.03 mmol/l. Ethanol increased UDP-galactose ten-fold simultaneous with a rise in hepatic outflow ratio of lactate to pyruvate to about 300 from 10; this indicates that ethanol inhibits epimerase. In experiments with increasing galactose elimination rates, the concentration of galactose-1-P increased much less than the concentration of galactose, and the phosphorylation of galactose therefore seems to be rate-limiting. In vitro galactokinase is inhibited by galactose-1-P. In the present study ethanol increased galactose-1-P five to ten times, and the reduction of Vmax and Km by ethanol could be explained by uncompetitive inhibition by galactose-1-P with Ki about 0.1 mmol/l. Ethanol decreased UDP-glucose to about 40% and UTP to less than 5%, probably due to trapping as UDP-galactose. This may depress the forward transferase reaction, and therefore the other co-substrate galactose-1-P rises--and inhibits galactokinase.