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Respiratory problems are common in patients with chronic liver diseases. The most common causes are disorders that are not related to liver diseases such as asthma and COPD. In addition certain liver diseases that are associated with specific pulmonary abnormalities, and conditions associated with end stage liver disease like tense ascites and intercostal muscular wasting are considered. Finally two unique disorders characterizing by vascular abnormalities independent of cardiorespiratory disorder-the hepatopulmonary syndrome (HPS) and portopulmonary hypertension (POPH) are observed. These disorders have different pathogenesis, different clinical pictures, treatment and prognosis. This article reviews the epidemiology, pathophysiology, clinical features, evaluation and current therapy of these two disorders.

Objective: Previous studies have demonstrated that CYP2D6 polymorphism is associated with liver cirrhosis. The aim of the present study was to find out whether CYP2D6*4, the poor metabolizer allele can predict fibrosis progression rate., Methods: Seventy-five Caucasian patients with chronic hepatitis C infection were recruited. They were divided into two groups, 'fast fibrosers' and 'slow fibrosers', according to Poynard's fibrosis progression curves. Sixty-two patients underwent liver biopsy. Twenty healthy neonates were included as control population. DNA was extracted from peripheral blood and CYP2D6*4 was tested by polymer chain reaction using fluorescent hybridization probes in a lightCycler instrument., Results: Forty-two patients were classified as 'fast fibrosers' and 33 patients as 'slow fibrosers'. The frequency of CYP2D6*4 allele in the 'fast fibrosers' (34.5%) was significantly higher compared with the 'slow fibrosers' (15%) (P-value=0.007). There was no significant difference between the frequency of CYP2D6*4 in the 'slow fibrosers' (15%) compared with the controls (12.5%). Carrier state of CYP2D6*4 was the only covariate that was significantly positively correlated with fast progression to cirrhosis (odds ratio=6.5, P=0.01)., Conclusion: This study indicates for the first time that CYP2D6 genotype might be a significant predictor of liver fibrosis progression rate in chronic hepatitis C patients.

Background/aims: Combination therapy of interferon-alpha (IFNalpha) and the oral nucleoside analog, ribavirin is the standard treatment for individuals suffering from hepatitis C virus (HCV) infection. Several studies have shown combination therapy of IFN and antioxidants is therapeutically beneficial in these patients. Ursodeoxycholic acid (UDCA) is a hydrophilic bile acid possessing antioxidant properties. This study evaluated the clinical outcome and extent of oxidative stress in a group of non-responding and disease-relapsed HCV patients treated with IFNalpha, ribavirin and UDCA (triple therapy) for 6 months., Methodology: Twenty patients with chronic HCV disease were treated with triple therapy for six months. During this period, they were monitored for the presence of HCV RNA, standard serum parameters of liver function and the plasma levels of lipid peroxides (LP) and glutathione (GSH) as indices of oxidative stress. The patients were reassessed six months after completion of treatment., Results: During the 6-month treatment period, the health status of the patients improved reflected by falls in the serum activities of alanine and aspartate aminotransferases and gamma-glutamyl transpeptidase and an initial lowering of viral (HCV RNA) load. Six months after cessation of treatment, the patients showed biochemical and virological evidence of disease relapse. The elevated plasma LP levels normalized during the treatment period and remained within normal levels 6 months after completion of treatment. Plasma GSH levels fluctuated within the normal range over the 12-month observation period., Conclusions: Treatment of individuals with chronic HCV hepatitis with triple therapy comprising IFNalpha, ribavirin and UDCA improves the health status, as well as lowering the extent of oxidative stress in these individuals. This treatment regimen also resulted in a sustained lowering of plasma lipid peroxide levels in the face of laboratory evidence of disease relapse. This preliminary study is unable to provide an apt explanation for the persistence of normal plasma LP levels in the face of evidence of disease relapse 6 months after completion of treatment. However, we believe these preliminary findings are sufficiently intriguing to warrant further study. Such investigations should include more patients with assessment of the extent of hepatic fibrosis during and after completion of treatment to determine whether this treatment can modify the natural progress of the disease.

Hyponatremia in advanced cirrhosis and ascites or congestive heart failure (CHF) is the result of an inappropriate increase in vasopressin secretion, which acts through activation of specific V(2) receptors in the distal renal nephron to increase water reabsorption. This study investigates the efficacy and safety of 3 different doses of the V(2) receptor antagonist, VPA-985, in correcting hyponatremia over a 7-day inpatient study period. Forty-four hospitalized patients (33 patients with cirrhosis, 6 with CHF, and 5 with syndrome of inappropriate antidiuretic hormone (SIADH) were studied on a constant sodium intake, with VPA doses of 25, 125, and 250 mg twice daily or placebo. Serum sodium measurements were repeated after every daily dose, and the next dose withheld for excessive serum sodium rises. Fluid intake was adjusted according to previous 24-hour urinary outputs. Adverse events were based on clinical signs of dehydration or encephalopathy. VPA-985 produced a significant overall aquaretic response compared with placebo, with significant dose related increases in free water clearance (P <.05) and serum sodium (P <.05), without significant changes in orthostatic blood pressure or serum creatinine levels. Five patients (50%) on 250 mg twice daily had to have medication withheld on multiple occasions. End-of-study plasma vasopressin levels increased significantly in the 2 larger dose groups. In conclusion, VPA-985 appears effective and safe in appropriate doses in correcting abnormal renal water handling and hyponatremia in conditions associated with water retention. Higher doses of VPA-985 may produce significant dehydration and will require close monitoring with their use.

Background/aims: Primary biliary cirrhosis (PBC) is a chronic liver disease that results in cholestasis and bile duct loss. Ursodeoxycholic acid (UDCA) has been shown to reduce hepatocellular damage in PBC. The study attempted to quantify perisinusoidal collagenization and the number of apoptotic bodies in PBC liver biopsies from patients in a randomized control trial treated with UDCA compared to those who received placebo., Methods: Twenty-eight patients with PBC (10 cirrhotic, 18 non-cirrhotic; 13 treated with UDCA, 15 treated with placebo) were compared with 32 controls with normal hepatic histology on light microscopy. Liver biopsies were examined for degree of perisinusoidal fibrosis and apoptotic activity using electron microscopy., Results: The degree of perisinusoidal fibrosis and apoptotic activity was similar in pretreatment biopsies of UDCA and placebo-treated patients. After two years of placebo, patients showed a significant increase in fibrosis (P < 0.001). In contrast, there were no changes in non-cirrhotic and a decrease in fibrosis in cirrhotic patients given UDCA. At baseline, PBC patients had higher numbers (apoptotic cells/100 hepatocytes +/- SE) of apoptotic cells (7 +/- 3), than controls (2 +/- 0.5) (P < 0.05), with no difference between cirrhotic and non-cirrhotic patients in the two groups of patients. After two years, the numbers of apoptotic cells in UDCA-treated patients decreased significantly compared to baseline (3 +/- 2) (P < 0.05); with placebo patients the number of apoptotic cells increased (12 +/- 5) (P < 0.05)., Conclusion: Treatment with UDCA prevents the deposition of perisinusoidal collagen and reduces the apoptotic activity in PBC patients after 2 years of therapy.

Subtle cardiac abnormalities have been described in patients with cirrhosis. Natriuretic peptide hormones have been reported to be sensitive markers of early cardiac disease. We postulate that plasma levels of N-terminal pro-atrial natriuretic peptide and brain natriuretic peptide could be used as markers of cardiac dysfunction in cirrhosis. The aim of the study was to evaluate the levels of N-terminal pro-atrial natriuretic peptide and brain natriuretic peptide and their relationship with cardiac structure and function in patients with cirrhosis. The study population comprised 36 patients with cirrhosis of mixed aetiologies, but with no cardiac symptoms; 19 of the patients had ascites and 17 did not. The subjects underwent (i) trans-thoracic two-dimensional echocardiography, and (ii) radionuclide angiography for measurements of cardiac structural parameters, diastolic and systolic function. Levels of N-terminal pro-atrial natriuretic peptide and brain natriuretic peptide were also measured. The results were compared with those from eight age- and sex-matched healthy volunteers. Compared with the controls, the baseline mean ejection fraction was increased significantly in both patient groups (P=0.02), together with prolonged deceleration times (P=0.03), left atrial enlargement (P=0.03) and interventricular septal thickening (P=0.02), findings that are compatible with diastolic dysfunction. Levels of N-terminal pro-atrial natriuretic peptide and brain natriuretic peptide were significantly higher in all patients with cirrhosis with ascites (P=0.01 and P=0.05 respectively), but in only some of the pre-ascitic cirrhotic patients, compared with controls. All high levels of brain natriuretic peptide were correlated significantly with septal thickness (P<0.01), left ventricular diameter at the end of diastole (P=0.02) and deceleration time (P<0.01). We conclude that elevated levels of brain natriuretic peptide are related to interventricular septal thickness and the impairment of diastolic function in asymptomatic patients with cirrhosis. Levels of brain natriuretic peptide may prove to be useful as a marker for screening patients with cirrhosis for the presence of cirrhotic cardiomyopathy, and thereby identifying such patients for further investigations.

Objective: Malnutrition is common in patients with decompensated cirrhosis and refractory ascites. The use of transjugular intrahepatic portosystemic stent shunt (TIPS) is effective in eliminating ascites. The purpose of this study was to investigate the effect of TIPS and resolution of refractory ascites on the nutritional status of patients with decompensated cirrhosis., Methods: Fourteen consecutive patients with refractory ascites and a Pugh score of 9.0+/-0.5 had a TIPS insertion. Biochemical data, resting energy expenditure (REE), total body nitrogen (TBN), body potassium (TBK), body fat (TBF), muscle force (MF), and food intake were recorded before TIPS, and at 3 and 12 months after the procedure., Results: Ten patients completed the study. Baseline values for REE, TBN, TBF, MF, and energy intake were below normal at baseline. There was a significant increase in dry weight, TBN, and REE at 3 and 12 months compared with baseline. TBF improved significantly at 12 months. There was a trend toward an increase in energy intake (p = 0.072). There was no change in protein intake, TBK, MF, and Pugh score., Conclusion: In cirrhotic patients with refractory ascites, resolution of the ascites after TIPS placement resulted in improvement of several nutritional parameters, especially for body composition.

Objectives: To determine what changes are occurring in patients with primary sclerosing cholangitis (PSC) by examining perisinusoidal macrophages (Kupffer cells) in liver biopsies; 2-to measure transforming growth factor beta (TGFbeta) as a marker of fibrosis in these patients., Design and Methods: Transmission electron microscopy and immunohistochemistry of 15 PSC, 26 primary biliary cirrhosis (PBC), 30 alcoholic liver disease (ALD) and 51 with normal histology was used. Five PSC, 30 ALD and 120 normal volunteers were sampled for serum levels of TGFbeta., Results: There was a three-fold increase in relative numbers of Kupffer cells in PSC compared to PBC and to patients whose livers had normal histology. In PSC there was an accumulation of perisinusoidal macrophages, which was not associated with focal necrosis or with cholestasis. The levels of TGFbeta in PSC were 54 +/- 2 in cirrhotic versus 34 +/- 5 in non-cirrhotic patients (p < 0.005)., Conclusion: The persistent activation of these macrophages may lead to the chronic release of TGFbeta and contribute to chronic inflammation, fibrosis and cirrhosis.

Objective: (i) to characterize the profile of tumor necrosis factor alpha (TNF alpha), interleukin-6 (IL-6), IL 10, Fas-ligand and transforming growth factor beta (TGF beta), chronic hepatitis C (HCV) patients with genotype 1; (ii) to determine the influence of triple therapy (TT) with interferon alpha (IFN alpha) + ribavirin + ursodeoxycholic acid on these cytokines and (iii) to establish the relationship between the pro-inflammatory cytokines and the outcome of treatment., Design and Methods: 22 patients infected with HCV-genotype 1 a/b and non responsive to IFN-alpha monotherapy were enrolled in the TT. The controls were 49 HCV naïve patients with genotype 1 a/b. Cytokine levels were measured using enzyme-linked immunosorbent assay (ELISA)., Results: The baseline TNF alpha values (pg/mL) in the sustained responders (SRs) (63+/-3) were significantly lower than non-responders (NRs) (140+/-16) (p < 0.001). Baseline Fas (ng/mL) levels were also lower in SRs (4.3+/-0.2) than NRs (5.4+/-0.4) (p < 0.05)., Conclusions: Fas and TNF alpha may be used as serological markers of inflammation and effectiveness of therapy.

Cellular mechanisms for Na(+) retention in portal hypertension are undefined, but epithelial Na(+) channels (ENaC) may be involved. Under high-salt diet, ENaC are absent from distal colon of rat but can be induced by mineralocorticoids such as aldosterone. Presence of rat ENaC was determined by amiloride inhibition of (22)Na(+) uptake in surface colonocytes 7 and 14 days after partial portal vein ligation (PVL) or sham surgery. At both times, uptake inhibition was significantly increased in PVL rats. Presence of mRNA transcripts, determined by RT-PCR, demonstrated that channel alpha- and gamma-subunits were similarly expressed in both groups but that beta-subunit mRNA was increased in PVL rats. This confirms that there was induction of rat ENaC and indicates that beta-subunit has a regulatory role. Urinary Na(+) was decreased for 3 days after PVL but was not different at other times, and serum aldosterone levels were elevated at 7 days, at a time when urinary Na(+) output was similar to that of sham-operated rats. We conclude that PVL leads to induction of ENaC in rat distal colon. An increase in aldosterone levels may prevent natiuresis and is probably one of several control mechanisms involved in Na(+) retention in portal hypertension.

We have shown, in animal models as well as in retrospective human study, that some degree of decreased thyroid function is beneficial for subjects with liver damage of various etiologies. Therefore, we herein present the results of a cohort population study. Between 1991 and 1994, 18 patients (12 women and 6 men; mean age, 59 +/- 24 years) with both biopsy-proven active cirrhosis (5 hepatitis C virus, 4 hepatitis B virus, 1 immunocompromised host, 2 primary biliary cirrhosis, 1 alcoholic, and 5 cryptogenic; Child's-Pugh criteria: A-8, B-8, C-2) and primary or induced (by either drug or surgery) thyroxine-treated hypothyroidism were prospectively followed. Each patient was examined at least twice yearly and served as their own control. The thyroid of the profiled patients ranged between euthyroidism and subclinical hypothyroidism. Liver function tests were evaluated and compared in states of normal versus increased thyroid-stimulating hormone (TSH) blood levels. A significant improvement in alanine aminotransferase (p < 0.001), alkaline phosphatase (p < 0.0001), albumin (p < 0.001), and bilirubin (p < 0.01) was found in the increased TSH group. Prothrombin time was also found to be significantly better (p < 0.001). We conclude that euthyroid patients with liver cirrhosis might benefit from a controlled hypothyroidism.

Objective: Total serum bile acid concentrations are elevated in individuals with liver disease. Ursodeoxycholic acid (UDCA) therapy in such patients results in a further significant rise in plasma levels to the extent that it becomes the major circulating bile acid. In laboratory animals, bile acids, such as taurocholic acid, have also been shown to possess a diuretic-like action, as they can promote diuresis, natriuresis, and kaliuresis by inhibiting tubular sodium reabsorption. The aim of the present study was to assess the effect of 1 month's UDCA therapy on cardiovascular function in cirrhotic patients., Methods: Two groups of patients with cirrhosis were studied, six with primary biliary cirrhosis (PBC) and six with postnecrotic liver cirrhosis (PNC). Cardiovascular function was assessed by determination of blood pressure, heart rate, and by two-dimensional and pulsed Doppler echocardiography., Results: In PBC patients, 1 month's treatment with UDCA significantly reduced diastolic volume without changing systolic, diastolic, and mean blood pressures, heart rate, systolic and stroke volumes, ejection fraction, cardiac output, and systemic vascular resistance. In PNC patients, UDCA significantly reduced cardiac output, with a tendency to reduce left ventricular volumes, without any changes in systolic, diastolic, and mean blood pressures., Conclusions: UDCA caused reductions in diastolic volume in the PBC patients and cardiac output in the PNC patients. Such reductions are not unlike that seen in individuals treated with diuretics. This diuretic-like action deserves further study, particularly in cirrhotic patients who are also being treated with diuretics or show evidence of cardiac myopathy.

Background: Systemic hypotension may result in postoperative renal failure in jaundiced patients. Attenuated responsiveness to catecholamines and hypovolaemia has been reported in jaundiced animals and may be a mechanism contributing to the increased susceptibility of jaundiced patients to haemorrhagic shock. This suggests that an alternative to vasoactive amines to control perioperative hypotension could be desirable., Methods: This study evaluated the pressor response to vasopressin in normovolaemic 3-day bile duct-ligated rats and in 3-day bile duct-ligated rats after an acute controlled haemorrhage. It also evaluated the response after volume loading with 0.9 per cent saline, 7.5 per cent saline, colloid and mannitol before controlled haemorrhage. In addition, blood volume was measured using radiolabelled albumin. All the data obtained from bile duct-ligated rats were compared with data from sham-operated animals., Results: Attenuated pressor responses to vasopressin were not observed in either normotensive bile duct-ligated rats or in the bile duct-ligated rats subjected to controlled haemorrhage. Volume loading with the four fluids over the dosing range 2.5-7.5 microliters per g body-weight in bile duct-ligated rats reversed the susceptibility to haemorrhagic hypotension., Conclusion: Although no reduction in blood volume was demonstrated, bile duct-ligated rats may have a reduced effective blood volume manifesting itself as a latent hypovolaemia and/or tendency to hypotension. Preoperative fluid loading could be beneficial because it corrects hypovolaemia and improves cardiovascular function, as well as improving the cardiovascular response to haemorrhage.

Objective: Large volume paracentesis is an effective treatment for refractory ascites, but the need for routine infusion of albumin or other volume expanders remains controversial. The aim of this study was to assess the short term effects of a single 5-L paracentesis without albumin replacement on total central blood volume, systemic and renal hemodynamics, sodium homeostasis, and neurohumoral factors., Patients and Methods: Twelve patients with biopsy-proven cirrhosis and tense, diuretic-resistant ascites were studied before and 48 h after a single 5-L paracentesis without albumin infusion. Systemic hemodynamics and total central blood volume were assessed using radionuclide angiography. Glomerular filtration rate and effective renal plasma flow were measured by inulin and para-aminohippurate clearances, respectively. Lithium clearance was used as an index of proximal tubular reabsorption of sodium. In addition, plasma concentrations of neurohumoral factors were determined., Results: Total central blood volume was 2.41 +/- 0.33 L/m2 (mean +/- SEM) before and 2.34 +/- 0.18 L/m2 48 h after large volume paracentesis (p = 0.76). Similarly, no differences were detected in the cardiac index, glomerular filtration rate, effective renal plasma flow, urinary sodium excretion, hematocrit, plasma renin activity, or concentrations of plasma aldosterone, norepinephrine, or atrial natriuretic factor., Conclusions: A single large volume paracentesis without albumin replacement causes no disturbances in systemic and renal hemodynamics 48 h after the procedure. These results suggest that a single 5-L paracentesis without albumin infusion is a safe and satisfactory short term option for the management of patients with cirrhosis and tense, diuretic-resistant ascites.

Background: Appropriate use of orthotopic liver transplantation (OLT) requires continued assessment of the indications for transplantation as a number of diseases are associated with a poor prognosis. High-risk patients are those who have a poor survival or high incidence of recurrent disease (patients with tumours, hepatitis B- or hepatitis C-induced cirrhosis, fulminant hepatic failure or primary graft non-function). In addition, retransplantation may be associated with a poor outcome., Methods: A retrospective review was made of the records of all adult patients undergoing OLT at this hospital between October 1985 and July 1994., Results: A total of 396 liver transplants were performed in 364 patients. The 1- and 3-year actuarial survival rates were 81 and 69 per cent respectively. The overall survival rate of high-risk patients was significantly lower than that for all OLT recipients (P < 0.05). While no patients transplanted for hepatitis C have developed graft failure, recurrent hepatitis occurred in 15 of 35 patients., Conclusion: Strict selection criteria and appropriate perioperative investigations and interventions are required to improve the results of OLT in these high-risk patients.

Prostaglandins (PG) are involved in the regulation of many physiological processes in the liver and play a major role in the pathophysiology and treatment of liver diseases. In addition to their effects of cell growth and immune function, PGs have shown cytoprotective effects on hepatocytes in various toxic, ischemic, and infectious models of liver injury. Although the mechanisms for these beneficial effects have not been precisely delineated, synthetic PG analogues have increasingly been used in patients with acute liver failure and chronic liver disease. There is also increasing evidence suggesting that PGs may reduce the early morbidity and mortality associated with liver transplantation, particularly in the context of primary graft nonfunction and renal dysfunction associated with cyclosporine and tacrolimus therapy. PG analogues have also been used for the treatment and control of recurrent hepatitis B virus infection in liver allograft recipients. The purpose of this review is to evaluate the role of PGs in hepatic physiology and disease and to review the use of synthetic PG analogues in the clinical settings of liver failure and transplantation.

The clinical presentation and outcome of 32 children with primary sclerosing cholangitis (PSC) are reviewed, the largest North American series. The majority of patients were diagnosed in their second decade (median age: 13 years). Four children presented before the age of 2 years, but none in the neonatal period. Seventeen patients had inflammatory bowel disease (IBD), all with colitis, 14 ulcerative colitis, and 3 Crohn's disease. Eight patients presented with chronic liver disease before clinical onset of IBD. Only 8 of 32 patients were jaundiced at presentation. Fifteen of 32 had a normal serum alkaline phosphatase (ALP) level at presentation. Nine children presented with features similar to those of autoimmune hepatitis. Cholangiography was performed in all cases and classified by a scoring system specifically developed for pediatric patients. Intrahepatic disease predominated; in only three cases a common bile duct stricture was identified requiring stenting. Findings on the initial liver biopsy were classified according to Ludwig's criteria for staging PSC: there were 15 biopsies in stages 1 to 2 and 17 biopsies stages 3 to 4. HLA class I and II antigens were determined in 27 patients. An increased incidence of HLA B8 and DR2(15) but not DRw52a (DRB3*0101) was found. Anti-neutrophil cytoplasmic antibody (ANCA) was positive in 10 of 24 patients tested. Survival analysis indicated that a later age at presentation, splenomegaly, and prolonged prothrombin time (PT) at presentation were significant contributors to the prediction of poor outcome (i.e., death or listing for transplantation). Liver transplantation was successfully performed in seven children. Physicians must maintain a high index of suspicion of PSC in any child or young adult presenting with chronic liver disease, especially in the presence of IBD, even with a normal serum alkaline phosphatase level.

Background: Mutated p53 acts as a dominant oncogene, whereas the wild type (wt) p53 gene product suppresses cell growth. Abnormalities in the p53 gene are reported in more than 50% of malignant tumors. Recently, an allelic loss of chromosome 17p, where the p53 gene is located, was found to be more frequent in hepatocellular carcinoma (HCC) cell lines and human tumors. In addition, in half of the cases of HCC from endemic areas for hepatitis B virus and aflatoxin, a hot spot point mutation at codon 249 was detected, as previously reported. Missense mutations in p53, mdm-2 complex formation, and other unknown mechanisms may lead to stabilization of the gene product, thus rendering it detectable by immunohistochemistry., Methods: To assess the relationship between p53 status at a premalignant stage and in HCC, the authors studied the immunohistologic expression of p53 in HCC and in the adjacent nontumorous resected liver tissue, using monoclonal antibody to wt and mutated p53., Results: Twelve of the 14 patients with liver tumors had HCC. Of the 12 patients with HCC and underlying cirrhosis, 8 (67%) had increased p53 expression in HCC cells. Eight of the 12 patients with p53-positive HCC cells had p53 overexpression in the nontumorous hepatocytes within regenerative nodules adjacent to HCC tissue. Three of 21 cirrhotic livers without a detectable tumor had increased p53 expression in the regenerative nodules. None of the 12 patients with chronic active hepatitis without cirrhosis or the 13 with a normal liver histology had increased p53 expression., Conclusion: p53 overexpression in some cirrhotic livers and in nontumorous livers of patients with HCC may indicate a normal p53 gene response to cellular stress or, alternatively, to an abnormally or mutated p53 gene, and could occur before the development of HCC.

Obliterative lesions in portal veins (PVs) and hepatic veins (HVs) of all sizes are known to occur in cirrhotic livers. PV lesions have generally been attributed to thrombosis, but the pathogenesis of the HV (veno-occlusive) lesions is unknown. We have studied 61 cirrhotic livers removed at transplantation to clarify the prevalence, distribution, and pathogenesis of venous lesions, as well as the association of these lesions with other morphological features and clinical morbidity. Intimal fibrosis that is highly suggestive of healed HV or PV thrombosis was found in at least 70% and 36% of livers, respectively. The distribution of HV lesions was patchy and largely confined to veins between 0.1 and 3 mm in diameter, suggesting multifocal origin in small veins. PV lesions were more uniform throughout the liver, suggesting origin in large veins with propagation to the small veins. HV lesions were associated with regions of confluent fibrosis (focal parenchymal extinction), and PV lesions were associated with regional variation in the size of cirrhotic nodules and a history of bleeding varices. These observations suggest that thrombosis of medium and large PVs and HVs is a frequent occurrence in cirrhosis, and that these events are important in causing progression of cirrhosis.

Background: To determine whether the orally active iron chelator deferiprone (1,2-dimethyl-3-hydroxy-pyridin-4-one) is efficacious in the treatment of iron overload in patients with thalassemia major, we conducted a prospective trial of deferiprone in 21 patients unable or unwilling to use standard chelation therapy with parenteral deferoxamine., Methods: Hepatic iron stores were determined yearly by chemical analysis of liver-biopsy specimens or magnetic-susceptibility measurements. Detailed clinical and laboratory studies were used to monitor safety and compliance., Results: The patients received deferiprone therapy for a mean (+/-SE) of 3.1 +/- 0.3 years. Ten patients in whom previous chelation therapy with deferoxamine had been ineffective had initial hepatic iron concentrations of at least 80 mumol per gram of liver, wet weight -- values associated with complications of iron overload. Hepatic iron concentrations decreased in all 10 patients, from 125.3 +/- 11.5 to 60.3 +/- 9.6 mumol per gram (P < 0.005), with values that were less than 80 mumol per gram in 8 of the 10 patients (P < 0.005). In all 11 patients in whom deferoxamine therapy had previously been effective, deferiprone maintained hepatic iron concentrations below 80 mumol of iron per gram., Conclusions: Oral deferiprone induces sustained decreases in body iron to concentrations compatible with the avoidance of complications from iron overload. The risk of agranulocytosis associated with deferiprone may restrict its administration to patients who are unable or unwilling to use deferoxamine.

Hyperinsulinemia and insulin resistance have been implicated in the pathogenesis of essential hypertension, with alterations in insulin-induced vasodilatation as one possible mechanism. The aims of this study were to assess the local vasodilatory action of insulin on a dorsal hand vein and the influence of sodium status on the insulin effect in healthy human subjects. Distensibility of a superficial hand vein and response to norepinephrine, insulin, and nitroglycerine were measured by the linear variable differential technique. Fourteen healthy subjects were studied after a low (20 mmol) and high (200 mmol) sodium diet for 7 days. All subjects gained weight (P < .005) and had higher central venous pressure (P = .003) on a high sodium intake. Baseline mean arterial pressure, heart rate, and fasting plasma glucose levels were not significantly different between the two diets. High sodium diet, however, resulted in a higher calculated insulin/glucose ratio (P = .029) implying reduced tissue sensitivity to insulin. Baseline plasma norepinephrine was significantly higher on the low (1.29 +/- 0.13 nmol/L) compared with the high sodium diet (0.79 +/- 0.11 nmol/L) (P < .005). The dorsal hand vein was significantly more dilated at the baseline level on a low sodium (2.60 +/- 0.12 mm) than on a high sodium diet (2.20 +/- 0.12 mm) (P = .034). However, the maximal constriction achieved with norepinephrine was not significantly different between the two diets. Only an insulin dose of 0.8 mU/min on a low sodium diet was able to significantly dilate the norepinephrine preconstricted vein (77 +/- 9% of baseline diameter versus ED50) (P = .002).(ABSTRACT TRUNCATED AT 250 WORDS)

Lactulose has been used successfully in the treatment of portal-systemic encephalopathy but its exact mechanism of action is not known. The aim of this study was to observe the systemic effects of the colonic fermentation of an acute lactulose dose in cirrhotics and normal subjects. Six cirrhotic patients and 6 normal subjects were placed on 2 identical 2-d metabolic diets, 1 of which was supplemented with lactulose (1 g/100 kcals to a maximum of 28 g/d). Lactulose increased colonic fermentation in cirrhotic and normal subjects as evidenced by higher breath hydrogen and serum acetate levels. The increase in serum acetate levels after lactulose compared to control was similar in cirrhotic compared to normal subjects. However, the mean serum acetate concentration in the cirrhotics was significantly greater than that in the control subjects (p = 0.039), indicating increased endogenous production, or decreased peripheral utilization of acetate by the cirrhotic liver, or both. No change was observed in blood ammonia, glucose, insulin, or free fatty acid levels with lactulose.

Ursodeoxycholic acid, a dihydroxyl bile acid normally present in human beings in minimal amounts, becomes incorporated into the bile salt pool when taken orally. In cholestasis, bile acids are retained in the liver and are hepatotoxic. Ursodeoxycholic acid is the least-known hepatotoxic bile acid, has choleretic properties and is reported to benefit patients with chronic cholestasis. In a nationwide Canadian controlled trial, 222 patients with primary biliary cirrhosis were treated with ursodeoxycholic acid (14 mg/kg/body wt/day) or placebo for 24 mo. Only patients with a diagnosis confirmed by liver biopsy and serum positive for antimitochondrial antibodies were enrolled; 88% were symptomatic on entry. The primary outcome measure was percent change in total serum bilirubin from baseline to final follow-up. Treated patients (111) and controls (111) were comparable with regard to age, gender, biochemical parameters and liver histological condition. Although treatment was not associated with any improvement in symptoms, ursodeoxycholic acid therapy caused the bilirubin to fall significantly within the first 3 mo of therapy (p < 0.001). Significant falls in serum alkaline phosphatase, aminotransferases, cholesterol and IgM levels were also noted in the treated group. Improvement in some histological features was observed but there was no difference between the groups in the number of patients who reached the endpoints of death or liver transplantation. Ursodeoxycholic acid, given to patients with primary biliary cirrhosis, leads to an improvement in serum markers of cholestasis. A larger sample size is needed to determine whether ursodeoxycholic acid therapy has a beneficial effect on the survival of patients with primary biliary cirrhosis.

Although propylthiouracil has previously been shown to reduce the risk of mortality in alcoholic liver disease by 60%, generalized use of propylthiouracil for this condition has not occurred. Additional data are therefore presented on four aspects to provide a better assessment of its therapeutic effectiveness. First, the characteristics and the prognosis of dropouts were virtually identical in both the drug and placebo groups. Also the methodology and analysis employed, were designed to control for dropouts, thus providing an accurate interpretation of the outcome. Secondly, since 97% of the patients continued to drink, abstinence was not a precondition for the beneficial effect of propylthiouracil. However, the beneficial effect was observed most clearly in those patients who continued to drink at lower levels, whereas lower level drinking per se did not afford protection in placebo patients. Thirdly, serious side effects or clinical hypothyroidism occurred extremely rarely in these patients, many of whom have now received propylthiouracil for over 4 years. Fourthly, we discuss why the outcome in long-term clinical trials in alcoholic liver disease cannot be compared with effects observed in clinical trials lasting only a few weeks. Journal of Hepatology.

Early and accurate diagnosis and prognosis of patients with fulminant liver failure is of critical importance for optimum management. We investigated the role of transjugular liver biopsy in the management of patients with fulminant liver failure and assessed its value in comparison with the recently proposed King's College criteria. Sixty-one patients with fulminant liver failure, ages 2 to 82 yr, were retrospectively analyzed. The main outcome measures were survival vs. death or progression to orthotopic liver transplantation. Transjugular liver biopsy was successful in 60 of 61 patients, with a mean core tissue length of 2.1 cm. There were eight minor complications, all of which were managed conservatively. Biopsy specimens were evaluated for degree of fibrosis, percentage of hepatocellular necrosis and presence of bile duct proliferation, hepatocellular mitotic figures and binucleate hepatocytes for each of the 54 specimens available for analysis. In 34 of 54 patients (63%), the presumed clinical diagnosis was confirmed by transjugular liver biopsy. In 11 patients the procedure served to clarify clinical uncertainty, whereas in 9 of 54 (16.7%) the diagnosis was altered after transjugular liver biopsy. The percentage of necrosis was the only histological parameter that appeared to have significant discriminatory prognostic value, with only 2 of 19 survivors having greater than 70% necrosis. Twenty-one of these biopsy specimens were reviewed by two pathologists, and their degree of correlation for the various features was assessed. Almost perfect concordance was found between the two pathologists on the percentage of hepatocellular necrosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Cirrhotic patients with ascites refractory to diuretics also have blunted response to marked elevations of plasma atrial natriuretic factor levels alone or to moderate intravascular volume expansion by head-out water immersion. However, these patients usually undergo natriuresis after peritoneovenous shunting. To dissect the factors responsible for this response, we studied the effects on separate days of moderate intravascular volume expansion and highly elevated plasma atrial natriuretic factor levels (head-out water immersion and atrial natriuretic factor infusion) or marked volume expansion and moderate plasma atrial natriuretic factor level elevation (head-out water immersion and albumin infusion) in 13 alcoholic cirrhotic patients with massive ascites. Three of these patients, who responded to initial head-out water immersion with a negative sodium balance, served as controls. Unresponsiveness to head-out water immersion was confirmed in the remaining 10 patients on both days on the basis of blunted natriuretic response (urinary sodium excretion < 0.8 mmol/hr after 2 hr). In contrast, these 10 refractory patients were able to achieve negative sodium balance with both combinations. Mean urinary sodium excretion increased from a baseline level of 0.13 +/- 0.10 mmol/hr to a peak level of 2.29 +/- 0.61 mmol/hr after head-out water immersion and atrial natriuretic factor infusion and from 0.10 +/- 0.3 mmol/hr to 1.61 +/- 0.62 mmol/hr after head-out water immersion and albumin infusion. Both maneuvers were associated with suppression of plasma renin activity and serum aldosterone levels. With head-out water immersion and atrial natriuretic factor infusion, we noted a significant increase in 5' cyclic GMP levels, a second messenger of atrial natriuretic factor, indicating possible activation of atrial natriuretic factor receptors at the inner medullary collecting ducts. In contrast, with head-out water immersion and albumin infusion no such increase in levels occurred, indicating that the increase in urinary sodium excretion was mainly due to increased delivery of sodium to the cortical distal nephron, as indicated by a disproportionate increase in urinary potassium excretion. In conclusion, massive (as opposed to moderate) volume expansion or greatly elevated levels of plasma atrial natriuretic factor associated with moderate volume expansion can improve blunted atrial natriuretic factor responsiveness in cirrhotic patients with refractory ascites. This appears to be achieved by way of a marked increase in distal delivery of filtrate in the kidney, with or without activation of distal atrial natriuretic factor receptors in the inner medullary collecting ducts.

Background: Sodium retention in cirrhosis has been attributed to an imbalance between vasoconstrictive, antinatriuretic forces such as the renin aldosterone angiotensin system and the sympathetic nervous system, and vasodilatory, natriuretic agents such as atrial natriuretic factor (ANF). Patients with diuretic resistant refractory ascites may require peritoneovenous shunting (PVS) to control ascites., Methods: To study the factors responsible for the improvement in sodium homeostasis post-PVS, we compared the response to ANF infusion before and 1 month after PVS in 6 patients with massive ascites., Results: Before PVS, sodium excretion at baseline and in response to ANF infusion was blunted but became more normal post-PVS. ANF infusion post-PVS induced a significant increase in the glomerular filtration rate and filtration fraction and also in distal delivery of sodium. ANF's distal effect of increasing the fractional excretion of distally delivered sodium was present pre-PVS and was not significantly increased post-PVS. Changes in sodium handling were accompanied by a significant decrease in antinatriuretic forces (baseline aldosterone, 2079 +/- 507 vs. 647 +/- 17 nmol/L; P < 0.04) post-PVS., Conclusions: The improvement in sodium homeostasis and response to ANF infusion post-PVS appears to be associated with the decrease in antinatriuretic forces with the loss of massive refractory ascites. Thus, PVS restores the balance toward ANF responsiveness.

Resistance to the natriuretic action of atrial natriuretic factor (ANF) in cirrhosis with ascites has been correlated with rising levels of antinatriuretic factors, such as renin, angiotensin II (AII), and aldosterone, as well as increased sympathetic nerve activity. To determine whether AII can serve as a mediator rather than only as a marker of the antinatriuresis, a nonpressor dose of AII (5 ng/kg/min) was given during an ANF infusion in eight patients with cirrhosis and ascites who responded to ANF infusion with a natriuresis. Patients were maintained in metabolic balance and measurements of para-aminohippuric acid, inulin, and lithium clearance were taken before and during infusion of ANF with or without AII. Atrial natriuretic factor infusion was associated with a natriuretic response accompanied by an increase in glomerular filtration rate, filtration fraction, and lithium clearance compared with baseline. The addition of AII was associated with a return of the glomerular filtration rate to baseline, with no change in filtration fraction. This was reversible on withdrawal of AII infusion. Natriuresis induced by ANF occurred despite baseline elevations of the renin angiotensin aldosterone system and was associated with an increase in distal delivery of sodium and a decrease in fractional reabsorption of distally delivered sodium as estimated by lithium clearance parameters. Angiotensin II infusion exerted effects on both proximal and distal nephron sites to abrogate ANF-induced natriuresis. These results suggest that AII may serve as a mediator as well as a marker of resistance to the natriuretic effect of ANF in patients with cirrhosis and ascites.(ABSTRACT TRUNCATED AT 250 WORDS)

A working formulation for the role of ANF in the sodium retention of cirrhosis is summarized in Figure 4. Sodium retention is initiated early in cirrhosis, either as a result of hepatic venous outflow block or of primary vasodilation. The consequent intravascular volume expansion causes increases in ANF levels. At this stage of disease, the rise in ANF level is sufficient to counterbalance the antinatriuretic influences. However, this occurs at the expense of an expanded intravascular volume with the potential for overflow ascites. With progression of disease, disruption of intrasinusoidal Starling forces and loss of volume from the vascular compartment into the peritoneal compartment occur. This underfilling of the circulation may attenuate further increases in plasma ANF and promotes the activation of antinatriuretic factors. At this later stage of disease, elevated levels of ANF are insufficient to counterbalance antinatriuretic influences. Thus the role of ANF in cirrhosis is primarily beneficial in that it successfully attenuates the antinatriuretic forces in the compensated stage. Raised ANF levels have two potential deleterious effects. First, ANF may exacerbate arterial vasodilation, leading to further sodium retention. The primacy of vasodilatation has been proposed as an alternate formulation to the overflow and underfill hypotheses. Second, Epstein et al. found higher basal ANF levels in cirrhotic patients with edema than in those patients without edema. ANF is known to reduce plasma volume in anephric animals and to increase the ultrafiltration coefficients of isolated capillaries. Therefore it is conceivable that in the clinical setting in which antinatriuretic factors limit the renal responsiveness to ANF but in which ANF levels are elevated (i.e., cirrhosis, congestive heart failure, primary kidney disease), ANF itself may contribute to edema formation at the level of the peripheral microcirculation. In general, ANF likely has no primary role in the sodium retention in cirrhosis. In early compensated cirrhosis, ANF may maintain sodium homeostasis despite the presence of mild antinatriuretic factors. In late ascitic cirrhosis renal resistance to ANF develops, rendering it ineffective.(ABSTRACT TRUNCATED AT 400 WORDS)

The nature of sodium retention in cirrhosis complicated by ascites has been studied for the last 30 years. Resistance to the natriuretic action of atrial natriuretic peptide (ANP) may play a potential role in this sodium retention. To further evaluate this possibility, we studied 12 patients with biopsy-proven cirrhosis and ascites on 2 consecutive days after a 7-day period off diuretics while receiving a 20 mmol/day sodium restricted diet. Following a crossover design, patients underwent head-out water immersion (HWI) for 3 h and were infused with a alpha-human ANP for 2 h on 2 consecutive days. Blood and urine samples were collected hourly. Five patients displayed a natriuretic response to HWI, sufficient to achieve negative sodium balance, and these patients were termed responders. Each of these five patients also displayed a natriuretic response to ANP infusion. In contrast, the other seven patients (nonresponders) consistently failed to develop a natriuretic response to either maneuver. The two groups had similar elevations in plasma ANP concentrations, but at baseline differed in terms of plasma sodium, plasma renin activity, and serum aldosterone. Despite higher serum aldosterone concentrations, nonresponders excreted less potassium than responders during the peak effect of the interventions, suggesting greater sodium delivery to the aldosterone-sensitive nephron segment in responders. We conclude that the inability to mount an adequate sodium excretory response to HWI in patients with cirrhosis may be conveyed through increased antinatriuretic factors that decrease the sodium delivery to the medullary collecting duct and inhibit the natriuretic effect of ANP at that site.

It has been postulated that one of the mechanisms of hypotension associated with cirrhosis is an attenuated responsiveness to catecholamines despite the increased activity of the sympathetic nervous system and the elevated plasma concentrations of the sympathetic neurotransmitter, norepinephrine. This abnormality was studied in a dog model of portal hypertension and cirrhosis. Twelve weeks after bile duct ligation (n = 16), intrasplenic pressure rose significantly from 6.3 +/- 0.4 to 14.6 +/- 1.6 mmHg (p < 0.05), mean arterial pressure had fallen from 106 +/- 4 to 83 +/- 8 mmHg (p < 0.01), cardiac output had risen from 3.1 +/- 0.2 to 3.8 +/- 0.8 l/min (p < 0.05) and plasma norepinephrine concentrations rose from 0.22 +/- 0.12 to 1.17 +/- 0.52 nmol/l (p < 0.05). In 7 sham-operated dogs, the changes in these 4 variables over the same period were non-significant. In vivo pressor responsiveness was tested by studying the effects of intravenous and intra-arterial infusions of norepinephrine and the non-selective beta-adrenoceptor agonist, isoproterenol. In vitro responsiveness was tested by measuring the effects of isoproterenol on the isometric twitch of isolated ventricular strips and the effects of norepinephrine on femoral, mesenteric and renal arterial rings. There was no significant change in the in vivo responses of chronic bile-duct-ligated dogs at 12 weeks compared to the preoperative assessment, or to sham-operated dogs at 12 weeks. Furthermore, there was no significant difference between the in vitro responses of ventricular strips to isoproterenol or arterial rings to norepinephrine prepared from chronic bile-duct-ligated and sham-operated dogs.(ABSTRACT TRUNCATED AT 250 WORDS)

Over the past 20 years we have moved from a situation in which we had no therapy for alcoholic liver disease, through a period when any therapy we had was purely empirical, to an era where we have specific therapies for different aspects of this disease based upon sound pathogenic principles. In this short review, an attempt has been made to summarize these advances in the understanding of the pathogenesis of alcoholic liver disease. In particular, they explain why patients with severe acute alcoholic hepatitis continue to deteriorate in hospital despite withdrawal from alcohol, why they respond to corticosteroids, why only a small percentage of patients develop cirrhosis, and why propylthiouracil may offer protection.

We have previously shown that unresponsiveness to atrial natriuretic factor is a marker of the severity of ascites. The tubular mechanisms are unknown, but it seems that increased reabsorption of sodium proximal to the main site of action of atrial natriuretic factor (i.e., the inner medullary collecting duct) plays an important role. We attempted to decrease the proximal reabsorption of sodium with mannitol in patients unresponsive to atrial natriuretic factor. The results of mannitol in such a group of patients has previously been conflicting. We studied 10 patients with massive, resistant ascites who were off diuretics and on a 20-mmol/day sodium diet for 7 days. Atrial natriuretic factor unresponsiveness was confirmed by failure of a 2-hr atrial natriuretic factor infusion to induce a natriuresis. The next day all patients received an infusion of 40 gm of mannitol and subsequently a combined infusion of mannitol and atrial natriuretic factor. Proximal reabsorption of sodium and water were evaluated by lithium clearance, and glomerular filtration rate and renal blood flow were evaluated by inulin clearance and p-aminohippurate clearances, respectively. Six patients responded to mannitol alone with an increased diuresis (from 39 +/- 7 to 148 +/- 35 ml/hr) and natriuresis (from 0.27 +/- 0.05 mmol/hr to 1.65 +/- 0.53 mmol/hr; p less than 0.05) (responders), whereas four did not (nonresponders). The combination of atrial natriuretic factor and mannitol induced a further significant increase in sodium excretion (3.28 +/- 0.68 mmol/hr) but not in urine excretion, compared with mannitol alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Recurrence of hepatitis is a well-documented complication of hepatitis B liver disease, post-transplantation. It is well established also that the earliest hepatocellular change is the appearance of hepatitis B viral (HBV) markers and that the disease is rapidly progressive. In this article on 17 liver transplants in 16 HBV positive patients with long-term follow-ups (100-1234 days), the distinctive pathologic features of this disease are emphasized: the extreme viral load, the steatosis, and/or fibrosis. An attempt to quantitate the magnitude of the viral burden was made and the result was a staggering figure. In one patient, an estimated 10(18) HBV core particles were present in the liver. One of two patterns of progression were noted. In four patients in addition to the massive nuclear hepatitis B core antigen (HBcAg) and cytoplasmic hepatitis B surface antigen (HBsAg) positivity, superimposed hepatitic changes led to diffuse hepatic fibrosis (fibroviral hepatitis B); and in another six patients, extraordinary hepatocellular viral marker positivity and steatosis were the hallmarks (steatoviral hepatitis B). Steatosis is not usually considered a feature of HBV liver pathology. These results suggest that more than one type of posttransfusion recurrent hepatitis B liver disease exists pathologically.

1. Systemic hypotension, blunted cardiovascular responsiveness to noradrenaline and an abnormal hypertensive pressor response to a postural change have been described in cirrhotic patients. 2. We have examined the role of blunted responsiveness in these abnormalities by studying basal arterial blood pressure and its response to a postural change (vertical head-up 90 degrees tilting) in conscious and pithed CCl4-treated (cirrhotic) rats, as well as assessing the pressor response to noradrenaline in vivo and the vascular contractile response to noradrenaline in vitro. 3. A diminished hypotensive response to a change in posture was found in pre-cirrhotic portal hypertensive rats, whereas an inverted hypertensive pressor response in the face of systemic hypotension occurred in the cirrhotic rats with portal hypertension. 4. The inverted pressor response was abolished in the pithed portal hypertensive cirrhotic rats. 5. The pressor response to noradrenaline in vivo in conscious cirrhotic rats and the vascular contractile responsiveness to noradrenaline in vitro were intact. 6. We conclude that blunted responsiveness to noradrenaline is not a contributory factor to the development of systemic hypotension or the inverted pressor response to a change in posture in cirrhosis.

Purpose: Sodium retention in cirrhosis has been attributed to an imbalance between vasoconstrictive antinatriuretic forces such as the sympathetic nervous system and vasodilatory natriuretic agents such as atrial natriuretic factor (ANF). With the development of refractory ascites, cirrhotic patients become unresponsive to the natriuretic effect of ANF. Animal data suggest that the sympathetic nervous system plays a key role in mediating the refractoriness to ANF. We therefore studied the relationship between sympathetic nerve activity (SNA) and the natriuretic response to ANF in normal subjects and cirrhotic patients. We also attempted to localize the intrarenal site of refractoriness to ANF by lithium clearance., Patients and Methods: Twenty-six patients with biopsy-proven cirrhosis and seven age- and sex-matched normal volunteers were studied after a week of 20 mmol/day sodium intake and no diuretics. Muscle SNA was recorded from the peroneal nerve (microneurography) and correlated with responsiveness to a 2-hour ANF infusion. Lithium clearance was used as a marker of sodium reabsorption proximal to the intramedullary collecting duct, the main site of ANF action. Plasma norepinephrine, renin, and aldosterone levels were also determined. Patients were categorized into three groups: nine patients free of ascites (by ultrasonography), five ascitic patients who responded to a 2-hour ANF infusion (i.e., had a natriuretic response to ANF above 0.83 mmol/hour), and 12 ascitic patients who did not respond., Results: Muscle SNA was greatly increased in the ascitic nonresponder patients compared with the normal subjects (64 +/- 4 versus 27 +/- 7 bursts/minute, p less than 0.001), moderately increased in ascitic responders (47 +/- 6 bursts/minute, p less than 0.05), but not significantly increased in nonascitic patients with cirrhosis (34 +/- 5 bursts/minute). SNA was positively correlated with plasma norepinephrine levels (r = 0.69; p less than 0.005) and inversely correlated with peak sodium excretion during the ANF infusion (r = -0.63; p less than 0.001). Plasma renin activity and aldosterone were markedly elevated in ascitic nonresponders, and normal in ascitic responders and nonascitic patients. Lithium clearance was reduced in ascitic patients compared with nonascitic patients, did not change after the ANF infusion, and correlated inversely with SNA (r = -0.61; p less than 0.01)., Conclusion: These results support the concept that the sympathetic nervous system is a factor in renal sodium handling in cirrhosis, especially in the initiation of sodium retention and the development of refractory ascites. Refractoriness to ANF might be explained, at least in part, by increased neurally mediated sodium reabsorption proximal to the intramedullary collecting duct, the main site of ANF action.

1. The effect of sodium intake on the natriuresis and hormonal changes induced by head-out water immersion was studied in seven normal subjects during head-out water immersion and on a control day while successively on 20 mmol of sodium/day and 100 mmol of sodium/day diets. The effects of head-out water immersion were compared with those seen on the control day for both diets. 2. The natriuresis on the 100 mmol of sodium/day diet was significantly greater than on the 20 mmol of sodium/day diet (natriuretic peak: 10.3 +/- 2.2 versus 3.9 +/- 1 mmol of sodium/h; P less than 0.01). The total sodium excretion during the 3 h of head-out water immersion was 26.2 +/- 2.0 mmol on the 100 mmol of sodium/day diet and 9.9 +/- 0.9 mmol on the 20 mmol of sodium/day diet (P less than 0.01). In contrast, the increase in the plasma atrial natriuretic factor level was similar on both diets (peak plasma atrial natriuretic factor level 23.1 +/- 1.9 versus 26.2 +/- 1 pg/ml; not significant). As expected, the baseline serum aldosterone level was higher on the 20 mmol of sodium/day diet and, despite a significant suppression, remained significantly higher at the end of the third hour of head-out water immersion (peak serum aldosterone level: 495 +/- 130 versus 197 +/- 26 pmol/l, P less than 0.06). Furthermore, there was an inverse relationship between the serum aldosterone level and the urinary sodium excretion at the time of peak natriuresis (r = -0.59, P less than 0.01). 3. We conclude that the effect of sodium intake on the natriuresis induced by head-out water immersion is more dependent upon anti-natriuretic agents, such as aldosterone, than on natriuretic factors, such as atrial natriuretic factor.