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Biomedical subjects

D Lebrec

Publications and source records attributed to D Lebrec.

At least 19 recordsLinked to original sources
PubMed2002

Comparison of the effect of terlipressin and albumin on arterial blood volume in patients with cirrhosis and tense ascites treated by paracentesis: a randomised pilot study.

BACKGROUND: Patients with cirrhosis and tense ascites treated by paracentesis alone have a decrease in effective arterial blood volume after ascites removal. Although intravenous albumin is effective in preventing paracentesis induced decreased arterial blood volume, its clinical use is controversial. As paracentesis induces arteriolar vasodilation which plays a role in the development of decreased effective arterial blood volume, administration of a vasoconstrictor (terlipressin) could prevent circulatory alterations due to paracentesis. AIMS: To perform a pilot study comparing the effects of terlipressin and albumin on effective arterial blood volume in patients with cirrhosis treated by paracentesis for tense ascites. METHODS: Twenty patients with cirrhosis and tense ascites were randomly assigned to be treated by either paracentesis and terlipressin or paracentesis and albumin. Terlipressin (3 mg) or albumin (8 g/l of removed ascites) were administered on the day of paracentesis. Effective arterial blood volume was assessed by measuring plasma renin concentrations at baseline and on the day of hospital discharge (4-6 days after treatment). Decreased effective arterial blood volume was defined as an increase in plasma renin concentrations on the day of hospital discharge of more than 50% of baseline values. RESULTS: Irrespective of the treatment group, mean values for plasma renin concentrations at hospital discharge did not differ from their respective baseline values (p=0.10). Baseline plasma levels of renin concentrations did not differ between the terlipressin and albumin groups (p=0.61). Changes from baseline in plasma renin concentrations did not differ between groups (p=0.39). Three patients in the terlipressin group and three in the albumin group developed decreased arterial blood volume. CONCLUSIONS: This randomised pilot study suggests that terlipressin may be as effective as intravenous albumin in preventing a decrease in effective arterial blood volume in patients with cirrhosis treated by paracentesis for tense ascites.

Albumins↗
PubMed2002

Idiopathic non-cirrhotic intrahepatic portal hypertension in the West: a re-evaluation in 28 patients.

BACKGROUND: Non-cirrhotic portal hypertension of unknown cause is a poorly understood condition attributed to obstructive portal venopathy. AIM: To reassess the manifestations, course, and causes, with special attention to thrombosis. METHODS: Analysis of a cohort of 28 patients. RESULTS: Gastrointestinal bleeding occurred in 11 patients. Liver failure developed at the time of concurrent disease in eight patients, including all four patients who died. Portal vein thrombosis developed in 13 patients. A prothrombotic disorder was found in 12 of 23 fully investigated patients. Hepatoportal sclerosis was observed in 11 patients (with associated perisinusoidal fibrosis and/or nodular regenerative hyperplasia in six); periportal fibrosis, perisinusoidal fibrosis, nodular regenerative hyperplasia, or a combination thereof were observed in other patients. A morphometric evaluation showed an increased number of portal vessels in patients with hepatoportal sclerosis. There was no relation between pathological results and haemodynamic findings or prothrombotic disorders. CONCLUSIONS: Outcome was related to associated conditions. Overlap in pathological, haemodynamic, and causal features suggests a single entity, with prothrombotic disorders as major causal factors, and injury to sinusoids as well as to portal venules as the primary mechanism. Activated coagulation could mediate vascular injury in the absence of thrombosis. Anticoagulation should be considered.

Adult↗
PubMed2001

Role of nitric oxide in hepatopulmonary syndrome in cirrhotic rats.

The hepatopulmonary syndrome (HPS) is characterized by intrapulmonary vascular dilatations and an increased alveolar-arterial oxygen difference (AaPO(2)). Exhaled nitric oxide (NO) concentrations are elevated, suggesting that pulmonary NO overproduction may be the mechanism underlying HPS. We investigated whether common bile duct ligation in rats results in lung NO overproduction and whether normalization of NO synthesis by a 6-wk course of N(G)-nitro-L-arginine methyl ester (L-NAME) (5 mg x kg(-)(1) x d(-)(1)) prevents HPS. Untreated cirrhotic rats showed increases in AaPO(2) and in cerebral uptake of intravenous (99m)Tc-labeled albumin macroaggregates (indicating intrapulmonary vascular dilatations), with decreases in pulmonary vascular resistance and in pulmonary vasoconstriction induced by angiotensin II and hypoxia. Increases were found in exhaled NO; pulmonary total and calcium-dependent NO synthase (NOS) activities; and pulmonary expression of inducible and, to a lesser extent, endothelial NOS. Accumulation of intravascular macrophages accounted for the inducible NOS expression. L-NAME normalized AaPO(2), brain radioactivity, pulmonary vascular resistance, reactivity to hypoxia and angiotensin II, exhaled NO, and NOS activities. These findings suggest that HPS and the associated reduced response to pulmonary vasoconstrictors seen in untreated cirrhotic rats are related to increased pulmonary NO production dependent primarily on increases in the expression and activities of inducible NOS within pulmonary intravascular macrophages.

Animals↗
PubMed2001

Early administration of vapreotide for variceal bleeding in patients with cirrhosis.

BACKGROUND: In patients with cirrhosis, pharmacologic or endoscopic treatment may control variceal bleeding. However, the effects of early administration of a somatostatin analogue followed by endoscopic treatment are unknown. METHODS: We studied the effects of treatment with vapreotide, a somatostatin analogue, begun before endoscopic treatment in 227 patients with cirrhosis who were hospitalized for acute upper gastrointestinal bleeding. The patients were randomly assigned to receive vapreotide (a 50-microg intravenous bolus followed by an infusion at a rate of 50 microg per hour for five days) or placebo within a mean (+/-SD) of 2.3+/-1.5 hours after admission. All the patients received endoscopic treatment a mean of 2.6+/-3.3 hours after the infusion was begun. After the exclusion of 31 patients whose bleeding was not caused by portal hypertension, there were 98 patients in each group. RESULTS: At the time of endoscopy, active bleeding was evident in 28 of 91 patients in the vapreotide group (31 percent), as compared with 43 of 93 patients in the placebo group (46 percent) (P=0.03). During the five-day infusion, the primary objective--survival and control of bleeding--was achieved in 65 of 98 patients in the vapreotide group (66 percent) as compared with 49 of 98 patients in the placebo group (50 percent) (P=0.02). The patients in the vapreotide group received significantly fewer blood transfusions (2.0+/-2.2 vs. 2.8+/-2.8 units, P=0.04). Overall mortality rates at 42 days were not significantly different in the two groups. CONCLUSIONS: In patients with cirrhosis and variceal bleeding, the combination of vapreotide and endoscopic treatment is more effective than endoscopic treatment alone as a method of controlling acute bleeding. However, the use of combination therapy does not affect mortality rates at 42 days.

Blood Transfusion↗
PubMed2001

Role of small-conductance Ca2+-dependent K+ channels in in vitro nitric oxide-mediated aortic hyporeactivity to alpha-adrenergic vasoconstriction in rats with cirrhosis.

BACKGROUND/AIMS: In vitro studies have shown that cirrhotic aortas are hyporeactive to the contractile effect of vasoconstrictors because upregulated endothelial nitric oxide-synthase (NOS) overproduces nitric oxide (NO). Although stimulation of endothelial small-conductance Ca2+-dependent K+ (SK(Ca)) channels may elicit vasorelaxation in normal arteries, the role of these channels in cirrhosis-induced hyporeactivity is unknown. Thus, the aim of the present study was to investigate the role of endothelial SK(Ca) channels in cirrhosis-induced, NO-mediated, in vitro aortic hyporeactivity to alpha1-adrenergic vasoconstrictors. METHODS: Isolated thoracic aortas from cirrhotic and normal rats were used. The effects of apamin, a selective SK(Ca) channel blocker, were measured on the vascular reactivity to phenylephrine. In addition, SK(Ca) channel protein expression was studied. The effects of iberiotoxin and charybdotoxin, blockers of other K(Ca) channels, were also studied in cirrhotic aortas. RESULTS: Apamin suppressed cirrhosis-induced aortic hyporeactivity to phenylephrine in an endothelium-dependent, NOS-inhibitor-sensitive manner. SK(Ca) channel protein was overexpressed in cirrhotic aortic walls. Iberiotoxin abolished cirrhosis-induced aortic hyporeactivity to phenylephrine in an endothelium-dependent but NOS-inhibitor-resistant manner. Charybdotoxin did not induce any significant increase in phenylephrine-elicited contraction. CONCLUSIONS: In cirrhotic aortas, the overexpression and overactivity of endothelial SK(Ca) channels contributes to in vitro NO-mediated hyporeactivity to the contractile action of alpha1-adrenergic agonists.

Adrenergic alpha-Agonists↗
PubMed2001

Aortic hyporeactivity to norepinephrine induced by lipopolysaccharide in cirrhotic rats: beneficial effects of a non-steroidal anti-inflammatory drug coupled with a nitric oxide donor.

BACKGROUND AND AIMS: Cirrhosis is associated with a hyperdynamic syndrome and arterial vasodilation that is related to nitric oxide (NO) synthase 3 overactivity. Septic shock is frequently associated with cirrhosis and with a vascular induction of NO synthase 2. The aims of this study were to compare the effects of lipopolysaccharide (LPS) in normal and cirrhotic rats, and to test the effects of a nonsteroidal anti-inflammatory drug (NSAID) coupled with a (NO) donor. METHODS: Cirrhotic rats received NO-flurbiprofen, flurbiprofen or vehicle followed by LPS or placebo 15 min later. The heart rate and mean arterial pressure of rats were monitered for 5 h. Thoracic aortic rings were removed and contracted with the use of norepinephrine. Nitric oxide synthase activity was measured in the aorta and stomach of cirrhotic rats. RESULTS: Arterial pressure decreased in cirrhotic rats in the vehicle/LPS and flurbiprofen/LPS groups. After LPS administration, the heart rate of rats increased in all groups. In the aortic rings, LPS induced hyporeactivity to norepinephrine in all groups except the NO-flurbiprofen group. This hyporeactivity was abolished after preincubation with Nw-nitro-L-arginine (L-NNA). Nw-nitro-L-arginine had no effect on norepinephrine-induced vasoconstriction in the NO-flurbiprofen/LPS group. Nitric oxide synthase 2 activity in the stomach and aorta of cirrhotic rats was increased in each group except in the NO-flurbiprofen group after LPS administration. Pretreatment with NO NSAID prevented aortic hyporeactivity to norepinephrine in cirrhotic rats treated with LPS as it probably inhibited the NO synthase 2 induction. CONCLUSIONS: These findings suggest that NO-flurbiprofen has a beneficial hemodynamic effect in cirrhotic rats and may help to prevent LPS aortic hyporeactivity.

Analysis of Variance↗
PubMed2001

Regulation of splanchnic perfusion.

In splanchnic arteries, vasodilators decrease the cytosolic free calcium concentration ([Ca(2+)]i) by inducing Ca(2+)sequestration and extrusion, by limiting the entry of extracellular Ca(2+)via L-type Ca(2+)channels and by decreasing the agonist-induced mobilization of intracellular Ca(2+). Cyclic GMP kinase and membrane hyperpolarization are important mediators of the decrease in [Ca(2+)]i. Vasoconstrictors increase [Ca(2+)]i by mobilizing intracellular Ca(2+)from the sarcoplasmic reticulum and by stimulating extracellular Ca(2+)entry via L-type Ca(2+)channels. Activation of G proteins, inositol trisphosphate, diacylglycerol and membrane depolarization are important mediators of the increase in [Ca(2+)]i.

Endothelium, Vascular↗
PubMed2001

Hemodynamic, metabolic and hormonal responses to oral glibenclamide in patients with cirrhosis receiving glucose.

BACKGROUND: In patients with cirrhosis, glucose may induce splanchnic and renal vasodilation. Since the antidiabetic sulfonylurea glibenclamide is known to induce splanchnic and renal vasoconstriction in portal hypertensive animals, this drug may inhibit glucose-induced hemodynamic responses in patients with cirrhosis. The aim of the present study was to investigate, in patients with cirrhosis, the short-term effects of glibenclamide on hemodynamic and humoral responses to glucose. METHODS: Patients were randomly assigned to receive either glibenclamide (5-mg tablet) or a placebo. All patients received an infusion of 10% glucose (62.5 ml/h for 12 h) that was started at the same time as glibenclamide or placebo administration. Studies were performed prior to and 90 min after glibenclamide or placebo. RESULTS: Glibenclamide (i.e. glibenclamide plus glucose) significantly increased plasma insulin concentrations and glycemia while placebo (i.e. glucose alone) significantly increased glycemia but did not change plasma insulin levels. Glibenclamide did not significantly change the hepatic venous pressure gradient while this value was significantly increased following glucose alone. Glibenclamide did not significantly change renal blood flow and glomerular filtration rate while glucose alone significantly increased renal blood flow without affecting the glomerular filtration rate. Glibenclamide significantly decreased cardiac index while glucose alone did not change this value. CONCLUSIONS: In patients with cirrhosis receiving glucose, glibenclamide blunted glucose-induced splanchnic and renal vasodilation. In addition, glibenclamide per se induced a decrease in cardiac index. These findings should be taken into account when glibenclamide is administered to patients with cirrhosis and type 2 diabetes.

Administration, Oral↗
PubMed2001

Relationships between haemodynamic alterations and the development of ascites or refractory ascites in patients with cirrhosis.

OBJECTIVE: In patients with cirrhosis, the relationships between haemodynamic alterations and the development of ascites or the occurrence of refractory ascites are unknown. The aim of the present study was to compare haemodynamic measurements obtained in patients with non-refractory ascites to haemodynamic measurements obtained in patients without ascites and in patients with refractory ascites. METHODS: A cohort of 121 patients was prospectively studied, of whom 29 patients did not have ascites, 45 had non-refractory ascites and 47 had refractory ascites. Splanchnic, renal and systemic haemodynamics were measured in all patients. RESULTS: The hepatic venous pressure gradient was significantly higher in patients with non-refractory ascites than in patients without ascites (18.5 +/- 0.8 mmHg versus 15.8 +/- 0.7 mmHg). Renal and systemic haemodynamics did not significantly differ between patients with non-refractory ascites and patients without ascites. The glomerular filtration rate and renal blood flow were significantly lower in patients with refractory ascites than in patients with non-refractory ascites (77 +/- 4 versus 107 +/- 5 ml/min and 867 +/- 62 versus 1,008 +/- 68 ml/min, respectively). Splanchnic and systemic haemodynamics did not significantly differ between patients with refractory ascites and patients with non-refractory ascites. CONCLUSIONS: In patients with cirrhosis, an increase in portal hypertension was the sole haemodynamic alteration related to the development of ascites. Renal vasoconstriction (and subsequent renal hypoperfusion and hypofiltration) was the only haemodynamic alteration related to the occurrence of refractory ascites. The development of ascites or refractory ascites was not associated with any alteration in systemic haemodynamics.

Aldosterone↗
PubMed2001

Pathogenesis of portal hypertension.

Portal hypertension is defined by an elevation in portal pressure and is associated with haemodynamic alterations. Haemodynamic changes are characterized by a hyperdynamic circulation in the splanchnic and systemic territories and a reduced pressure effect of vasoconstrictive substances. They were observed in both patients and animals with different types of portal hypertension. In this review, the main results and their mechanisms of the splanchnic and systemic haemodynamic alterations in portal hypertension are discussed.

Animals↗
PubMed2000

The role of nitric oxide in the reduction of protein kinase C-induced contractile response in aortae from rats with portal hypertension.

BACKGROUND/AIMS: Protein kinase C plays a role in the regulation of vascular cell contraction but its activity may be reduced by nitric oxide. In portal hypertension, the exact mechanism by which nitric oxide induces vascular hyporeactivity to vasoconstrictors is unclear. The aim of this study was to investigate the role of the interaction of nitric oxide and protein kinase C in the vascular reactivity in isolated aortae from portal vein-stenosed rats. METHODS/RESULTS: The contractile response to phorbol 12,13-dibutyrate, a protein kinase C activator, was significantly reduced in portal vein-stenosed aortae compared to sham-operated aortae. Preincubation with N-nitro-L-arginine or endothelium removal enhanced the response to phorbol 12,13-dibutyrate. The hyporesponsiveness to phorbol 12,13-dibutyrate in portal vein-stenosed rat aortae was only corrected after endothelium removal. The time course of contractions induced by phorbol 12,13-dibutyrate showed that the contraction was maintained for 2 h in sham-operated aortae and decreased to baseline in portal vein-stenosed rat aortae. This decrease was inhibited by N-nitro-L-arginine preincubation or endothelium removal. Protein kinase C downregulation caused a more marked reduction of phenylephrine-induced contraction in portal vein-stenosed aortae than in sham-operated aortae. The time course of total nitric oxide synthase activity in the presence of phorbol 12,13-dibutyrate showed a decrease in nitric oxide synthase activity after 30 min in both groups. Nitric oxide synthase activity remained stable for 120 min in sham-operated aortae but returned to basal level in portal vein-stenosed aortae. CONCLUSIONS: Hyporeactivity to vasoconstrictors in portal vein-stenosed rat aortae may be due, in part, to a decrease in protein kinase C activation caused by nitric oxide overproduction.

Animals↗
PubMed2000

Aquaretic effects of niravoline, a kappa-opioid agonist, in patients with cirrhosis.

BACKGROUND/AIMS: In patients with cirrhosis, decreased renal water excretion is a common complication. Niravoline (RU51599), a kappa-opioid receptor agonist, has been shown to induce an aquaretic response. The aim of this study was to evaluate the aquaretic effect and tolerance of niravoline in patients with cirrhosis. METHODS: Biochemical tests and hemodynamic values were determined before and 1, 2, 3 and 24 h after niravoline administration at doses ranging from 0.5 to 2 mg iv in 18 patients with cirrhosis. RESULTS: Diuresis significantly increased in the first hour from 64+/-9 to 146+/-31 ml/h, and returned to basal values after 3 h. Free water clearance also significantly increased, reaching the positive range at 1 h. Plasma osmolality significantly decreased at 2 h (from 290+/-4 to 286+/-4 mOsm/kg). Plasma sodium concentrations increased significantly at 3 h (from 133+/-1 to 134+/-1 mEq/l). Heart rate and arterial pressure did not change. The highest doses (1.5 mg or 2 mg) induced personality disorders and mild confusion within 2 h. These effects reversed completely within 8 h. CONCLUSION: This study shows that niravoline administration induces an aquaretic response and is well tolerated, at moderate doses, in patients with cirrhosis. Thus, moderate doses of niravoline may be useful for treating patients with cirrhosis and water retention.

Benzeneacetamides↗
PubMed2000

Effects of lipopolysaccharide on TNF-alpha production, hepatic NOS2 activity, and hepatic toxicity in rats with cirrhosis.

BACKGROUND/AIMS: Septic shock results in high mortality in patients with cirrhosis. Nitric oxide synthase 2 (NOS2) is induced by bacterial lipopolysaccharides (LPS) and plays a major role in the inflammatory response to bacterial infections. Little is known about the regulation of NOS2 in cirrhosis under septic conditions. Thus, the aim of this study was to determine tissue NOS2 activity, serum nitrate and tumor necrosis factor (TNF-alpha) levels and hepatic toxicity in cirrhotic rats after LPS administration. METHODS: Serum nitrates, TNF-alpha and transaminases were determined after LPS-administration in rats with secondary biliary cirrhosis and in sham-operated rats. Liver, lung, aortic and peritoneal macrophage NOS2 activities were determined by converting L[14C] arginine into L[14C] citrulline in a calcium free medium. Nitrate and TNF-alpha production were determined in a culture medium of peritoneal macrophages after in vivo LPS administration. RESULTS: LPS (1.5 mg/kg) induced 50% mortality in cirrhotic rats and no mortality in sham-operated rats. After LPS, TNF-alpha, nitrate and transaminase levels were significantly higher in cirrhotic rats compared to sham-operated rats. After LPS administration, there were no differences in NOS2 activity in the aorta, lungs, or peritoneal macrophages of the two groups, whereas NOS2 activity was significantly higher in the cirrhotic liver compared to the normal liver. CONCLUSIONS: In rats with cirrhosis, LPS administration induces higher mortality, hepatic toxicity, hepatic NOS2 activation and TNF-alpha release than in sham-operated rats. These results confirm the harmful role of septic shock in liver disease.

Animals↗
PubMed2000

Prospective study on the application of the Baveno II Consensus Conference criteria in patients with cirrhosis and gastrointestinal bleeding.

BACKGROUND/AIMS: This study aimed to evaluate the Baveno II criteria defining key events in variceal bleeding. METHODS: These criteria were applied to 196 patients with cirrhosis admitted for upper gastrointestinal bleeding due to portal hypertension and enrolled in a trial. Blood pressure, heart rate, hematocrit and clinical signs of upper digestive tract hemorrhage were recorded for 5 days. The blind overall clinical judgment of hemodynamic stability was recorded separately by the Steering Committee. RESULTS: The evaluation of several hemodynamic criteria was left to the judgment of the clinician. The first time point for the control of bleeding, fixed at 6 h after admission, was impractical since 13% of the patients had not yet received specific treatment. The independent judgment did not agree in 38% of 82 cases without control of bleeding. In 15% of cases this was due to tachycardia. Calculation of several judgment criteria was not defined in the Baveno II criteria: survival without bleeding at 5 days, transfusion rate, and length of hospital stay. CONCLUSIONS: Although the Baveno II criteria have improved the definitions of key events, the criteria are hampered by limits such as false positive criteria of failure to control bleeding. We make several proposals for improvement.

Blood Transfusion↗