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At least 469 records · Page 26Linked to original sources
PubMed1996

Exaggeration of acute liver damage by hepatic sympathetic nerves and circulating catecholamines in perfused liver of rats treated with D-galactosamine.

Effects of electrical stimulation of the hepatic nerves on acute liver damage were examined using isolated rat liver perfused in situ, 24 hours after intraperitoneal injection with D-galactosamine (800 mg/kg). The leakage of lactate dehydrogenase (LDH) and aspartate aminotransferase (AST) from the liver was used as markers of acute liver damage. In perfused livers after treatment with galactosamine, nerve stimulation (20 V, 20 Hz, 2 ms) increased the leakage of LDH and AST about 3-fold over the basal level accompanied by the decrease in flow rate, whereas with control livers the leakage of LDH and AST into the effluent was almost undetectable throughout the perfusion. The rapid increase in the leakage of LDH and AST was observed during nerve stimulation even under conditions where perfusion flow was maintained constant. Such effects of hepatic nerve stimulation on galactosamine-treated livers were mimicked well by infusion of noradrenaline or phenylephrine, and inhibited by the alpha1-antagonist bunazosin. Artificial reduction of perfusion flow alone did not induce the rapid leakage of LDH and AST into the effluent. On the other hand, low concentration (10 nmol/L) of noradrenaline only minimally decreased the flow rate but apparently augmented liver cell damage. The acute liver damage augmented by noradrenaline was dependent on extracellular Ca2+. These results indicate that in the liver, already having been injured slightly, the activation of hepatic sympathetic nerves and circulating catecholamines exaggerates acute liver damage through an action on liver cells, which depends on the influx of extracellular Ca2+.

Adrenergic alpha-Agonists↗
PubMed2000

Two-step selective clamping of IVC for removal of hepatocellular carcinoma with intracaval extension.

Hepatocellular carcinoma (HCC) with retrohepatic intracaval extensions are difficult to treat. HCC may sometimes extend into the inferior vena cava (IVC) through two routes: via the right hepatic vein and via the inferior right hepatic vein. In such cases, in which tumor emboli are located both above and below the confluence of the hepatic vein with the IVC, we first remove the upper embolus during THVE, and then remove the lower one while the IVC is clamped obliquely in order to preserve the residual liver circulation.

Carcinoma, Hepatocellular↗
PubMed1996

Method for determination of bone alkaline phosphatase activity: analytical performance and clinical usefulness in patients with metabolic and malignant bone diseases.

We report the performance characteristics of an assay for determination of bone alkaline phosphatase (ALP) activity after immunoadsorption in microplate wells. Between-run imprecision was between 7.1% and 11.2%. The detection limit was 1.0 U/L. Comparisons with an immunoradiometric test for determination of bone ALP mass concentrations yielded the following regression equation: y = 3.11 + 1.33x with y, the bone ALP activity concentration (U/L) (and x, the bone ALP mass concentration microgram/L) (r +=0.974, n = 103). Using sera from patients with liver diseases and sera from patients with secondary hyperparathyroidism yielded a cross-reactivity of 20% for circulating liver ALP (and its membrane-bound isoform). In patients receiving renal transplants, Z-score analysis revealed that after transplantation the increase in bone ALP activity is more pronounced than total ALP activity. In tumor patients, receiver-operating characteristic analysis revealed that bone ALP activity shows the same diagnostic efficacy as total ALP activity in the detection of bone metastases (as assessed by bone scintigraphy). In multiple myeloma patients, suppressed osteoblast activity was well detectable by bone ALP activity determination.

Adult↗
PubMed1986

Peripheral androgen levels in peripuberal rams infected with Fasciola hepatica.

Three-month-old, Polled Dorset rams infected with Fasciola hepatica and uninfected control rams were monitored throughout the peripuberal phase for peripheral concentrations of testosterone and for body weight. No differences between groups occurred in these measurements from early spring to mid-autumn. However, the infected postpuberal rams demonstrated a reduced ability to remove exogenous testosterone from the circulation. Liver damage induced by moderate infections of flukes apparently impairs hepatic catabolism of this steroid but compensatory mechanisms appear to maintain circulating levels comparable to those of uninfected rams.

Animals↗
PubMed1977

[New aspects of liver scintigraphy (author's transl)].

The development of the scintillation camera computer scintigraphy has created new chances for nuclear medicine diagnosis of the liver. With the development of new 99mTc-labeled radiopharmacenticals the effectiveness of functional scintigraphy of the liver in the differential diagnosis of parenchymal and mechanical icterus could be considerably increased. Computer perfusion scintigraphy permits proof of circulatory changes in the liver without invasive techniques. Its importance lies in early diagnosis of portal hypertension and in pre- and post-operative assessment of liver circulation after shunt surgery.

Diagnosis, Differential↗
PubMed1994

A prospective randomized clinical trial of liver preservation using high-sodium versus high-potassium lactobionate/raffinose solution.

High-sodium as opposed to high-potassium lactobionate/raffinose preservation solution offers potential advantages in improving the quality of liver storage by reducing potassium-induced vasoconstriction and preventing hyperkalaemia on reperfusion. In our study we evaluated in a prospective trial (encompassing 40 consecutive cadaver donor hepatic retrievals and subsequent transplants) the efficacy of a high-sodium formulation versus the standard high-potassium solution. Quality of preservation was assessed by clinical indices of liver function in the intraoperative and early postoperative phases, including measurements of requirements for blood and blood products and potassium, circulating liver enzymes and bilirubin. Frequencies of acute rejection episodes and primary non-function were also recorded. No significant differences were evident in any of the measured parameters. Thus a sodium-based solution can be used for hepatic preservation, advancing the possibility that it may be possible to develop a single storage solution for clinical multi-organ donor operations.

Adult↗
PubMed2005

Protein-tyrosine phosphatase 1B deficiency protects against Fas-induced hepatic failure.

Genetic disruption of protein-tyrosine phosphatase 1B (PTP1B) in mice leads to increased insulin sensitivity and resistance to weight gain. Although PTP1B has been implicated as a regulator of multiple signals, its function in other physiological responses in vivo is poorly understood. Here we demonstrate that PTP1B-null mice are resistant to Fas-induced liver damage and lethality, as evident by reduced hepatic apoptosis in PTP1B-null versus wild type mice and reduced levels of circulating liver enzymes. Activation of pro-apoptotic caspases-8, -9, -3, and -6 was attenuated in livers from PTP1B-null mice following Fas receptor stimulation, although components of the death-inducing signaling complex were intact. Activation of anti-apoptotic regulators, such as the hepatocyte growth factor/Met receptor tyrosine kinase, as well as Raf, ERK1/2, FLIP(L), and the NF-kappaB pathway, was elevated in response to Fas activation in livers from PTP1B-null mice. Using PTP1B-deficient primary hepatocytes, we show that resistance to Fas-mediated apoptosis is cell autonomous and that signals involving the Met, ERK1/2, and NF-kappaB pathways are required for cytoprotection. This study identifies a previously unknown physiological role for PTP1B in Fas-mediated liver damage and points to PTP1B as a potential therapeutic target against hepatotoxic agents.

Animals↗
PubMed1982

[Adenine nucleotides and metabolites of glycolysis in the liver in auxiliary transplantation].

The metabolic state of the liver during preservation as well as in and after auxiliary transplantation was investigated in dogs. The biopsy was carried out by means of TRU-CUT biopsy needle. - The ATP concentration, the storage of energy, the amount of the adenine nucleotides, and the ATP/ADP quotient decrease in the preserved liver. The AMP concentration, the concentration of the hexosemonophosphates and the mass-effective quotient of the phosphofructokinase increase simultaneously. The energy supply is the glycolysis exclusively. A lactate accumulation is avoided by continuous perfusion. - The changeover of the anaerobic to the aerobic energy preparation took place by degrees after the recovery of the liver circulation. The ATP concentration, the ATP/ADP quotient, the storage of energy, and the amount of the adenine nucleotides increase in the transplanted liver. - An irreversible ischemic damage of the liver appears in the metabolic state of the organ by a massive decrease of the ATP concentration below 0.7 mmol/kg, the amount of the adenine nucleotides below 1.8 mmol/kg, and AMP concentration.

Adenine Nucleotides↗
PubMedDate not supplied

Current concept of halothane hepatitis (review).

Clinically, halothane is still a useful volatile anesthetic, but since many cases of liver disorders considered attributable to halothane have been reported up to date, a number of studies have been made on the etiology and mechanism of halothane hepatitis. There are at least two possible mechanisms of halothane hepatitis; the first is the direct toxic reaction associated with free radical that is related to reductive pathway enhanced by hypoxia, and the other is the immune--mediated reaction in which the antigen is associated with the oxidative and/or reductive route. However, the etiology and mechanism of halothane hepatitis have yet to be elucidated, and clinically there is no obvious evidence that halothane can induce hepatic disorders. We have concluded at present that the use of halothane should be avoided in patients with liver disorders, in patients under long-term administration of drugs that may induce enzymes involved in halothane metabolism, in patients with high allergic sensitivity, and in patients undergoing operations in which liver circulation is reduced.

Adult↗
PubMed1990

Dopexamine: studies in the general intensive care unit and after liver transplantation.

1. It has been suggested that the use of dopaminergic agents in the critically ill patient may reduce the incidence of renal failure and hence mortality. 2. Dopexamine hydrochloride is a new synthetic catecholamine. Like dopamine, it stimulates dopaminergic receptors. It also stimulates beta 2-adrenoceptors. Unlike dopamine, dopexamine has minimal effect at beta 1-adrenoceptors and no alpha-adrenoceptor activity. 3. Stimulation of renal dopaminergic and beta 2-adrenoceptors independently results in dilation of the renal vasculature. A natriuresis and diuresis is also promoted by dopaminergic stimulation. 4. A comparison between the administration of low dose dopamine and dopexamine in patients undergoing orthotopic liver transplantation resulted in less renal impairment and failure in the dopexamine group, although this did not achieve statistical significance. 5. Dopexamine elimination is reduced in the absence of hepatic function. 6. A patient with terminal liver failure was treated with dopexamine and although oxygen delivery was unchanged, oxygen consumption doubled. This suggests that dopexamine affects other organs as well as the kidneys.

Critical Care↗
PubMed1991

Pharmacokinetics of omeprazole in cirrhotic patients.

Omeprazole (CAS 73590-58-6), an H+, K+ ATPase inhibitor, is a potent suppressor of gastric acid secretion and a very active substance in the treatment of duodenal and gastric ulcers. The kinetic profile of omeprazole is well defined for healthy volunteers and for some high-risk population, but not so far for patients with liver disease. As the substance is mainly metabolized in the liver, changes in liver circulation and/or function might lead to changes in the pharmacokinetics of omeprazole. Aim of the study was to evaluate the kinetic profile in patients with liver disease and compare the results obtained in healthy volunteers, 16 subjects were included in the study: 8 patients with liver cirrhosis and 8 healthy volunteers. A single oral dose of omeprazole 20 mg was administered: plasma samples were collected for 24 h since omeprazole administration. The principal pharmacokinetic parameters were estimated for the two studied populations.

Adult↗
PubMed1994

Biochemical improvement of chronic hepatitis C after gastrointestinal bleeding.

Although chronic hepatitis C is frequently complicated by iron overload, it remains unclear whether iron cytotoxicity is involved in the disease process. Five patients with chronic hepatitis C showed rapid reduction of serum aminotransferase activity after gastrointestinal bleeding. Posthemorrhagic reduction of liver enzyme levels lasted for more than one week. Anemia was associated with a reduction of serum ferritin concentration. Considering the short half-lives of circulating liver enzymes, reduced release of enzymes, that is inactivation of cell lysis, is the likely cause of the improved biochemical indices. Reactive iron, which is cytotoxic for patients infected by HCV, may be rapidly incorporated into hemoglobin when erythropoiesis is stimulated. Our observation also suggests that intensive iron removal by phlebotomy is a safe, economic treatment for patients with chronic hepatitis C.

Aged↗
PubMed1994

The physiological position of the liver in the circulation is not a major determinant of its functional capacity.

The zonal patterns of gene expression in the liver of the rat are not affected by alteration of the afferent hepatic blood source. We investigated whether afferent hepatic blood source or flow rate affects the metabolic capacity of the liver. Using microsurgical techniques, we changed the afferent hepatic blood source to solely arterial blood, solely portal blood or solely caval blood. The transhepatic flow rate was four times higher in arterialized than in cavalized livers. Liver function was tested 2 wk after surgery. Three liver functions were tested (elimination of hepatic iminodiacetic acid from the liver and elimination of galactose and ammoniumbicarbonate from the circulation). Our results show that the afferent hepatic blood flow rate rather than the source of the afferent hepatic blood affects the elimination of the substrates tested. We found that at the physiological flow rate of approximately 15 ml/min and beyond, metabolic function does not depend on the flow of the afferent hepatic blood but that at lower flow rates the flow becomes a major determinant of the metabolic function of the liver. We conclude that the position of the liver within the circulation (i.e. between the gastrointestinal tract and the systemic circulation) is apparently not a prerequisite for adequate metabolic activity, at least for the substrates tested, provided that the liver is sufficiently perfused with blood.

Ammonia↗
PubMed1980

Hypophosphatasia (adult form): quantitation of serum alkaline phosphatase isoenzyme activity in a large kindred.

We used heat inactivation, L-phenylalanine inhibition, and electrophoresis on polyacrylamide gel and cellulose acetate membranes--with and without use of specific antisera against the liver-bone, intestinal, and placental isoenzymes--to distinguish and quantitate the different alkaline phosphatase isoenzymes in sera from 23 adult members of a kindred affected by the adult form of hypophosphatasia. Nine subjects had values for total activity more than two standard deviations below the mean values for age- and sex-matched normal persons. Bone isoenzyme was diminished in all nine, whereas liver isoenzyme was subnormal in only four. Phosphoethanolamine and phosphoserine in the urine of eight hypophosphatasemic individuals correlated inversely with both total and liver alkaline phosphatase activity in their serum, but not with the activity of the bone isoenzyme. Total activity in the serum of adult kindred members correlated best with the circulating liver isoenzyme activity. The findings suggest that altered hepatic metabolism is responsible for the increased urinary excretion of phosphoethanolamine, and perhaps phosphoserine, in hypophosphatasia.

Adult↗
PubMed1996

Structural and pathologic changes in the lung vasculature in chronic liver disease.

The hepatopulmonary syndrome results from erythrocytes bypassing the lung without oxygenation. In addition to ventilation-perfusion mismatching, the hypoxemia may result from portapulmonary shunting, passage around alveoli through pleural and hilar blood vessels, and intrapulmonary vascular dilatations. Dilated vascular channels between arteries and veins on the pleural surface are seen more often than dilated intrapulmonary capillaries in chronic liver disease. These anastomoses appear grossly as vascular "spider nevi" on the pleura. Portal vein-to-pulmonary vein anastomoses could produce arterial hypoxemia because the deoxygenated portal venous blood can mix with oxygenated pulmonary venous blood. There is an association of esophageal varices with the hepatopulmonary syndrome and anastomoses between the portal veins and pulmonary veins have been found in both animals and humans. As portal pressures increase, the mediastinal veins enlarge, enhancing the chance that they may penetrate the pleura and drain into pulmonary veins. Direct splenic injections in patients, however, suggest that this shunt pathway is uncommon and small. Pulmonary artery injection studies have demonstrated dilated intrapulmonary vascular segments in humans and animals. Dilation of capillaries may allow a more rapid flow through the lung and the greater distance between the erythrocyte and alveolar wall may make it more difficult to oxygenate rapidly passing erythrocytes. Pulmonary capillary dilation can explain the abnormalities of the perfusion lung scan and contrast echocardiogram that portapulmonary shunting cannot. Pulmonary hypertension may occur in chronic liver disease even without arterial hypoxemia, but it is rare. The prevalence of hypertensive pulmonary vascular disease in patients with cirrhosis of the liver is less than 1%, although a higher percentage (2%) has been found when patients with portal hypertension were studied by cardiac catheterization. The hypertensive pulmonary vascular disease (pulmonary arteriopathy with plexiform lesions) that occurs in patients with liver disease appears identical to that encountered in patients with congenital cardiac shunts and unexplained (primary) pulmonary hypertension.

Animals↗