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Dive into the research topics where Laurence M. Blendis is active.

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Featured researches published by Laurence M. Blendis.


Transplantation | 1989

Treatment of primary liver graft nonfunction with prostaglandin E1

Paul D. Greig; Graham M. Woolf; Stephen B. Sinclair; Abecassis M; Steven M. Strasberg; Bryce R. Taylor; Laurence M. Blendis; Riccardo A. Superina; Michael F.X. Glynn; Bernard Langer; Gary A. Levy

Primary nonfunction following orthotopic liver transplantation is characterized by rapidly rising serum transaminases, minimal bile production, and severe coagulopathy, which can progress to hypoglycemia, hepatic encephalopathy, and acute renal failure. Untreated it has a mortality of over 80% and to date the only treatment has been retransplantation. As a result of the beneficial effect of Prostaglandin E1 infusion in patients with fulminant hepatic failure, this trial was conducted to determine whether PGE1 would be of value in primary nonfunction. We have encountered 16 cases of primary nonfunction in 94 liver transplants, an incidence of 17%. Initially in the program, there were 6 occurrences of nonfunction that did not receive PGE1; 3 underwent retransplantation (2 survivors), 2 died awaiting another liver, and in one recovery of hepatocellular function occurred with supportive care but the patient died of cytomegalovirus infection. Ten patients received PGE1 within 4-34 hr of transplantation. Within 12 hr of treatment, 8 patients responded with a significant fall in the AST (129 U/hr) whereas, in the untreated group, the AST continued to rise (267 +/- 102 U/hr) at the same rate as prediagnosis (337 +/- 95 U/hr). At the conclusion of the infusion (4-7 days) in the 8 responders, there were significant decreases in AST (4386 +/- 546 U/L to 102 +/- 21 U/L), prothrombin time (22 +/- 2 to 12 +/- .4 sec) and partial thromboplastin time (45 +/- 3-29 +/- 4 sec), and significant increases in coagulation factor V (26 +/- 8 to 95 +/- 12%) and factor VII (10 +/- 5 to 61 +/- 4%). No serious side effects occurred, although 2 patients developed diarrhea, and abdominal cramps. Two patients treated with PGE1 were retransplanted at 10-36 hr and were considered nonresponders. Graft survival was 80% in the PGE1-treated group and 17% in the untreated group (P less than 0.05) and patient survival was 90% and 33%, respectively. This study suggests a potential benefit of PGE1 in the treatment of primary nonfunction.


Clinical Science | 1999

Role of cardiac structural and functional abnormalities in the pathogenesis of hyperdynamic circulation and renal sodium retention in cirrhosis.

Florence Wong; Peter Liu; Lesley Lilly; Arieh Bomzon; Laurence M. Blendis

The aim of this study was to assess the relationship between subtle cardiovascular abnormalities and abnormal sodium handling in cirrhosis. A total of 35 biopsy-proven patients with cirrhosis with or without ascites and 14 age-matched controls underwent two-dimensional echocardiography and radionuclide angiography for assessment of cardiac volumes, structural changes and systolic and diastolic functions under strict metabolic conditions of a sodium intake of 22 mmol/day. Cardiac output, systemic vascular resistance and pressure/volume relationship (an index of cardiac contractility) were calculated. Eight controls and 14 patients with non-ascitic cirrhosis underwent repeat volume measurements and the pressure/volume relationship was re-evaluated after consuming a diet containing 200 mmol of sodium/day for 7 days. Ascitic cirrhotic patients had significant reductions in (i) cardiac pre-load (end diastolic volume 106+/-9 ml; P<0.05 compared with controls), due to relatively thicker left ventricular wall and septum (P<0.05); (ii) afterload (systemic vascular resistance 992+/-84 dyn.s.cm(-5); P<0. 05 compared with controls) due to systemic arterial vasodilatation; and (iii) reversal of the pressure/volume relationship, indicating contractility dysfunction. Increased cardiac output (6.12+/-0.45 litres/min; P<0.05 compared with controls) was due to a significantly increased heart rate. Pre-ascitic cirrhotic patients had contractile dysfunction, which was accentuated when challenged with a dietary sodium load, associated with renal sodium retention (urinary sodium excretion 162+/-12 mmol/day, compared with 197+/-12 mmol/day in controls; P<0.05). Cardiac output was maintained, since the pre-load was normal or increased, despite a mild degree of ventricular thickening, indicating some diastolic dysfunction. We conclude that: (i) contractile dysfunction is present in cirrhosis and is aggravated by a sodium load; (ii) an increased pre-load in the pre-ascitic patients compensates for the cardiac dysfunction; and (iii) in ascitic patients, a reduced afterload, manifested as systemic arterial vasodilatation, compensates for a reduced pre-load and contractile dysfunction. Cirrhotic cardiomyopathy may well play a pathogenic role in the complications of cirrhosis.


Annals of Internal Medicine | 1991

Increased Sympathetic Outflow in Cirrhosis and Ascites: Direct Evidence from Intraneural Recordings

John S. Floras; Louis Legault; Gilles A. Morali; Kazuhiro Hara; Laurence M. Blendis

OBJECTIVEnTo determine if central sympathetic outflow is increased in patients with cirrhosis and ascites.nnnPATIENTSnEleven patients with cirrhosis and ascites, 8 patients with cirrhosis but without ascites, and 7 age-matched and 8 young healthy volunteers.nnnMETHODSnWith subjects supine, direct microneurographic recordings of efferent post-ganglionic muscle sympathetic nerve activity were obtained from the peroneal nerve, and sympathetic burst frequency was compared with subjects blood pressure, heart rate, sodium excretion, catecholamines, and plasma renin activity. All patients with cirrhosis were studied at least 5 days after withdrawal from all medications and after 7 days of a 20 mmol/d sodium, 1-L fluid-restricted diet. Age-matched volunteers were studied after 7 days of 20 mmol/d sodium intake and young healthy volunteers after 7 days of 150 mmol/d sodium intake.nnnRESULTSnSympathetic nerve activity in ascitic patients (65 +/- 15 bursts/min; mean +/- SD) was markedly increased, whether compared with patients with cirrhosis but without ascites (34 +/- 16 bursts/min; P less than 0.001), age-matched healthy volunteers on similar sodium intake (27 +/- 22 bursts/min; P less than 0.001), or young healthy subjects (21 +/- 10 bursts/min; P less than 0.001). The frequency of muscle sympathetic nerve discharge was directly related to plasma norepinephrine and epinephrine concentrations, plasma renin activity, and heart rate, all of which were increased in those patients with cirrhosis and ascites, and inversely related to 24-hour urinary sodium excretion, the fractional excretion of sodium, and subjects pulse pressures. Sympathetic nerve activity fell from 78 to 6 bursts/min in one patient after liver transplantation.nnnCONCLUSIONSnThis study provides the first direct evidence that elevated plasma norepinephrine concentrations in patients with cirrhosis and ascites are due to increased central sympathetic outflow. Sympathetic nerve activity is not increased in patients with cirrhosis but without ascites. Because there were direct positive correlations of sympathetic nerve activity with plasma norepinephrine concentrations, plasma epinephrine concentrations, plasma renin activity, and heart rate, the increase in central sympathetic outflow in patients with cirrhosis and ascites appears generalized and not restricted to muscle nerves. The anti-natriuretic effects of parallel increases in renal and muscle sympathetic nerve activity could account for the inverse correlation between muscle sympathetic nerve activity and sodium excretion.


Gastroenterology | 1995

Pattern of sodium handling and its consequences in patients with preascitic cirrhosis

Florence Wong; Peter Liu; Yasmin Allidina; Laurence M. Blendis

BACKGROUND/AIMSnThe initial abnormalities in the renal sodium handling in patients with cirrhosis before developing ascites remain unknown. The aim of this study is to further characterize sodium metabolism and the effects of sodium loading in preascitic cirrhosis.nnnMETHODSnEight male, preascitic patients with cirrhosis and 6 volunteers had their daily urinary sodium excretion level measured while on a strictly metabolically controlled diet, first consisting of 20 mmol then of 200 mmol sodium per day each for 7 days. Central blood volume, plasma norepinephrine, and atrial natriuretic factor levels were measured during each diet.nnnRESULTSnPreascitic patients with cirrhosis had significantly less daily urinary sodium excretion on both diets. Volume expansion in the patients with cirrhosis was indicated by significantly greater weight gain and higher atrial natriuretic factor levels for each diet. Patients with cirrhosis had central blood volume expansion (1725 +/- 54 mL/m2) compared with controls (1495 +/- 81 mL/m2; P = 0.03) on a low-sodium diet. This increased significantly in the controls (1864 +/- 164 mL/m2; P = 0.04) on a high-sodium diet, associated with suppression of plasma norepinephrine, but not in the patients with cirrhosis (1679 +/- 107 mL/m2; P > 0.05).nnnCONCLUSIONSnFailure of further central blood volume expansion in the patients with cirrhosis on high-sodium diet in the presence of significant weight gain suggests maldistribution away from the effective arterial blood volume. This study provides further reasons why preascitic patients with cirrhosis might benefit from sodium restriction.


The American Journal of Medicine | 1999

Long-term renal sodium handling in patients with cirrhosis treated with transjugular intrahepatic portosystemic shunts for refractory ascites.

Winnie Wong; Peter Liu; Laurence M. Blendis; Florence Wong

PURPOSEnThe long-term effects of transjugular intrahepatic portosystemic shunts on renal sodium excretion are not known. We sought to determine these long-term effects, as well as to measure the effects of a sodium load in patients who are free of ascites.nnnSUBJECTS AND METHODSnTen patients with cirrhosis who had been successfully treated with transjugular intrahepatic portosystemic stent shunt for refractory ascites were studied before the shunt and again at 6 and 14 months after the shunt while on a 22 mmol sodium/day diet. At 14 months they were also studied on a 200 mmol sodium/day diet for 7 days without diuretics. Renal sodium handling, central blood volume, neurohumoral factors, and hepatic function were measured.nnnRESULTSnSodium balance was negative at 6 months (urinary sodium excretion [mean +/- SD] 51 +/- 11 mmol/day versus 7 +/- 2 mmol/day pre-shunt; P < 0.05), was maintained at 14 months (22 +/- 4 mmol/day; P < 0.05 versus pre-shunt), and was associated with normalization of renin activity and aldosterone levels, but not norepinephrine levels, as well as significantly improved renal hemodynamic measurements. Sodium loading with 200 mmol/day resulted in weight gain associated with increased central blood volume and appropriate renal sodium handling in most but not all patients (urinary sodium excretion 188 +/- 14 mmol/day), despite persistent nonsuppressibility of sympathetic hyperactivity.nnnCONCLUSIONSnIn cirrhotic patients with refractory ascites treated with a transjugular intrahepatic portosystemic stent shunt, long-term renal sodium handling is improved. Adequate intravascular filling in ascites-free cirrhotic patients with normal portal pressure permits an improved but not normalized renal response to a sodium load, possibly due to persistently elevated sympathetic activity. Therefore, these patients should increase their sodium intake cautiously.


Cancer | 1995

P53 expression in patients with cirrhosis with and without hepatocellular carcinoma

Nelly Livni; Ahamed Eid; Yaron Ilan; Avraham Rivkind; Eliezer Rosenmann; Laurence M. Blendis; Daniel Shouval; Eithan Galun

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.


The American Journal of Medicine | 1991

Muscle sympathetic nerve activity and renal responsiveness to atrial natriuretic factor during the development of hepatic ascites

Gilles A. Morali; John S. Floras; Louis Legault; Sheldon W. Tobe; Karl L. Skorecki; Laurence M. Blendis

PURPOSEnSodium 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.nnnPATIENTS AND METHODSnTwenty-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.nnnRESULTSnMuscle 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).nnnCONCLUSIONnThese 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.


Transplantation | 1980

Allogeneic and xenogeneic hepatocyte transplantation in experimental hepatic failure.

Leonard Makowka; Lorne Rotstein; Falk Re; Judith A. Falk; Natalie Nossal; Bernard Langer; Laurence M. Blendis; Phillips Mj

Previous studies have demonstrated the efficacy of syngeneic hepatocyte transplantation in the treatment of D-galactos-amine-induced acute hepatic failure in Lewis strain rats. This report describes the efficacy and immunological consequences of allogeneic and xenogeneic hepatocyte transplantation in the same model. The i.p. administration of allogeneic (minor and major histoincompatibility) hepatocytes or xenogeneic (rabbit or porcine) hepatocytes at a dose of 4 × 107 cells/rat given at 48 hr after toxin all resulted in significant improvement in survival compared to that of controls, and also comparable to the results obtained with syngeneic hepatocyte transplantation. Sensitization to i.p. allogeneic (WF) hepatocyte administration was demonstrated by in vivo 51Cr release, indirect immunofluorescent technique, and accelerated skin allograft rejection. Similarly, the in vivo 51Cr release assay was able to detect sensitization to porcine hepatocytes. Despite evidence of immunogenicity, redosing with either WF or porcine hepatocytes resulted in no overt toxicity. Furthermore, presensitization by either WF hepatocytes or skin allografts did not adversely affect survival after WF hepatocyte treatment in D-galactosamine-induced hepatic failure in Lewis strain rats. These data demonstrate that histocompatibility is not a constraint to successful hepatocyte transplantation and that repeated treatments are potentially safe and efficacious despite sensitization.


The American Journal of Medicine | 1994

Toxic effects of intravenous and oral prostaglandin E therapy in patients with liver disease

Mark S. Cattral; Ibraham Altraif; Paul D. Greig; Laurence M. Blendis; Gary A. Levy

BACKGROUNDnProstaglandins are cytoprotective agents that have been shown to benefit patients with a variety of acute and chronic liver diseases. Few data exist on the frequency of adverse effects of prostaglandins in these patients.nnnMETHODSnWe retrospectively studied 105 patients with liver disease who were treated with either intravenous (i.v.) or oral prostaglandin E (PGE). Forty-four patients with primary nonfunction after liver transplantation and 36 patients with fulminant hepatic failure received i.v. PGE1 for 4.5 +/- 2.6 and 12.6 +/- 10.9 days, respectively. Twenty-five patients with recurrent hepatitis B viral infection after liver transplantation received oral PGE1 for 105 +/- 94 days or PGE2 for 464 +/- 399 days.nnnRESULTSnTwenty-six of 80 patients (33%) receiving i.v. PGE1 developed gastrointestinal and/or cardiovascular side effects and 8% developed arthritis. Twenty-three of 25 patients (92%) who received high-dose oral PGE1 or PGE2 incurred arthritis and/or gastrointestinal adverse effects. Twenty-five patients received prolonged PGE therapy (oral > 60 days; i.v. > 28 days). Of this group, 23 (92%) developed clubbing and cortical hyperostosis resembling hypertrophic osteoarthropathy. All adverse effects were dose related and resolved with reduction or cessation of therapy.nnnCONCLUSIONnPGE therapy resulted in a wide spectrum of multisystem adverse effects which were reversible with reduction or cessation of therapy. Although the administration of PGE was safe and generally well tolerated, close medical supervision is necessary to avoid serious side effects.


Journal of Surgical Research | 1980

Reversal of experimental acute hepatic failure in the rat

Leonard Makowka; Rudolf E. Falk; Lorne Rotstein; Judith A. Falk; Natalie Nossal; Bernard Langer; Laurence M. Blendis; M. James Phillips

Abstract A suitable animal model of acute fulminant hepatic failure was developed in the rat by the administration of the selective hepatotoxin, galactosamine hydrochloride. A dosage of 2.6 g/kg given intraperitoneally to Lewis rats resulted in reproducible, potentially reversible hepatic necrosis and high mortality. The ability of dispersed single-cell suspensions of syngeneic hepatocytes, allogeneic hepatocytes, and bone marrow to provide “support” so that liver recovery could occur was explored in this model. Syngeneic hepatocytes (4 × 107 cells) given intraperitoneally 48 and 60 hr after toxin administration increased survival to 70 and 66%, respectively, compared to a control of 0%. Hepatocytes prepared from Fischer strain animals which differ from Lewis strain at minor histocompatibility loci similarly improved survival (62.5%). Syngeneic bone marrow cells (4 × 107 cells) given intraperitoneally 24 hr after toxin administration improved survival to 62.5% compared to a control group of 0%. This effect is not mediated by a mature macrophage or lymphoid cell population, but is specific to the cells derived from bone marrow, since single-cell suspensions of splenocytes, thymocytes, and peritoneal exudate cells had no effect on increasing survival. The mechanism of action of hepatocytes and bone marrow cells and whether they act by the same or different mechanisms remain to be defined. Cellular transplantation may offer a new simple measure in the treatment of acute hepatic failure.

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Paul D. Greig

Toronto General Hospital

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Sheldon W. Tobe

Sunnybrook Health Sciences Centre

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