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Dive into the research topics where Lawrence B. Cohen is active.

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Featured researches published by Lawrence B. Cohen.


Canadian Medical Association Journal | 2004

Cutaneous nocardiosis complicating management of Crohn's disease with infliximab and prednisone

Sheldon M. Singh; Neil Rau; Lawrence B. Cohen; Howard Harris

INFLIXIMAB IS A CHIMERIC ANTI-TUMOUR NECROSIS FACTOR-α antibody that is efficacious in treating Crohns disease. However, its immunomodulatory properties increase susceptibility to opportunistic infections. We present a case of cutaneous Nocardia infection in a patient who was taking infliximab for Crohns disease. The case illustrates the challenges in the diagnosis and management of this disease and serves as a reminder of the complications associated with the use of immunomodulatory agents.


Translational Research | 2014

Biologic therapies in inflammatory bowel disease

Lawrence B. Cohen; Radu M. Nanau; Faustine Delzor; Manuela G. Neuman

Inflammatory bowel disease, including its 2 entities ulcerative colitis and Crohns disease, is a chronic medical condition characterized by the destructive inflammation of the intestinal tract. Biologics represent a class of therapeutics with immune intervention potential. These agents block the proinflammatory cascade that triggers the activation and proliferation of T lymphocytes at the level of the intestine, therefore reestablishing the balance between the pro- and anti-inflammatory messages. All 7 biologics showing clinical benefits in inflammatory bowel disease are monoclonal antibodies. The following systematic review discusses the pharmacokinetics and efficacy of the tumor necrosis factor blockers infliximab, adalimumab, certolizumab pegol, and golimumab. In addition, we describe the α4 integrin inhibitors natalizumab and vedolizumab, which are directed against cell adhesion molecules, as well as the interleukin 12/23 blocker ustekinumab.


The American Journal of Gastroenterology | 2003

Absence of symptomatic benefit of lansoprazole, clarithromycin, and amoxicillin triple therapy in eradication of Helicobacter pylori positive, functional (nonulcer) dyspepsia

Sander Veldhuyzen van Zanten; Richard N. Fedorak; Jean Lambert; Lawrence B. Cohen; Anita Vanjaka

OBJECTIVES:The aim of this study was to compare the effect of a combination of lansoprazole, clarithromycin, and amoxicillin (LCA) versus placebo on the severity of symptoms in functional dyspepsia patients who were positive for Helicobacter pylori (H. pylori).METHODS:This was a double-blind, randomized, controlled clinical trial in adult patients with functional dyspepsia who were H. pylori positive. Patients were randomized to 7-day treatment with LCA or identical looking placebo. H. pylori status was confirmed by the urea breath test performed at baseline, at 6 wk, and at 6 and 12 months. The severity of eight upper GI symptoms was measured on a five-point Likert scale. The main outcomes were the change in average severity of the dyspepsia summary score of the eight symptoms and the proportion of patients who improved ≥4 points on the dyspepsia summary score.RESULTS:A total of 157 patients were included in the intention-to-treat analysis. LCA achieved cure of H. pylori infection in 82% of patients compared to 6% in the placebo group. The severity of dyspepsia symptoms improved over the 12-month study period, but for none of the outcome measures was there a significant difference between LCA and placebo.CONCLUSION:There was no difference in sustained improvement of dyspepsia symptoms when LCA was compared with placebo. An 82% cure rate of H. pylori infection was observed with LAC.


Experimental Dermatology | 2008

Predicting possible zonisamide hypersensitivity syndrome

Manuela G. Neuman; Neil H. Shear; Izabella M. Malkiewicz; Mona Kessas; Amy W. Lee; Lawrence B. Cohen

Abstract:u2002 Zonisamide (ZNS) is an anticonvulsant (AC) that contains a sulpha moiety potentially triggering hypersensitivity syndrome reactions (HSR). The lymphocyte toxicity assay (LTA) is an in vitro drug rechallenge test, which is believed to reflect a decreased capacity of the individual to detoxify reactive metabolites. The study examined whether cross‐reactivity is present between ZNS and other AC and/or sulphonamides and if this HSR may be predicted using the LTA. The second aim was to determine age‐related differences in ZNS‐induced HSR. LTA was previously validated in patients who received sulphamethoxazole (SMX) or AC.


Experimental and Molecular Pathology | 2014

Alcoholic and non-alcoholic steatohepatitis.

Manuela G. Neuman; Samuel W. French; Barbara A. French; Helmut K. Seitz; Lawrence B. Cohen; Sebastian Mueller; Natalia A. Osna; Kusum K. Kharbanda; Devanshi Seth; Abraham Bautista; Kyle J. Thompson; Iain H. McKillop; Irina Kirpich; Craig J. McClain; Ramon Bataller; Radu M. Nanau; Mihai Voiculescu; Mihai Opris; Hong Shen; Brittany Tillman; Jun Li; Hui Liu; Paul G. Thomes; Murali Ganesan; Steve Malnick

This paper is based upon the Charles Lieber Satellite Symposia organized by Manuela G. Neuman at the Research Society on Alcoholism (RSA) Annual Meetings, 2013 and 2014. The present review includes pre-clinical, translational and clinical research that characterize alcoholic liver disease (ALD) and non-alcoholic steatohepatitis (NASH). In addition, a literature search in the discussed area was performed. Strong clinical and experimental evidence lead to recognition of the key toxic role of alcohol in the pathogenesis of ALD. The liver biopsy can confirm the etiology of NASH or alcoholic steatohepatitis (ASH) and assess structural alterations of cells, their organelles, as well as inflammatory activity. Three histological stages of ALD are simple steatosis, ASH, and chronic hepatitis with hepatic fibrosis or cirrhosis. These latter stages may also be associated with a number of cellular and histological changes, including the presence of Mallorys hyaline, megamitochondria, or perivenular and perisinusoidal fibrosis. Genetic polymorphisms of ethanol metabolizing enzymes such as cytochrome p450 (CYP) 2E1 activation may change the severity of ASH and NASH. Alcohol mediated hepatocarcinogenesis, immune response to alcohol in ASH, as well as the role of other risk factors such as its co-morbidities with chronic viral hepatitis in the presence or absence of human immunodeficiency virus are discussed. Dysregulation of hepatic methylation, as result of ethanol exposure, in hepatocytes transfected with hepatitis C virus (HCV), illustrates an impaired interferon signaling. The hepatotoxic effects of ethanol undermine the contribution of malnutrition to the liver injury. Dietary interventions such as micro and macronutrients, as well as changes to the microbiota are suggested. The clinical aspects of NASH, as part of metabolic syndrome in the aging population, are offered. The integrative symposia investigate different aspects of alcohol-induced liver damage and possible repair. We aim to (1) determine the immuno-pathology of alcohol-induced liver damage, (2) examine the role of genetics in the development of ASH, (3) propose diagnostic markers of ASH and NASH, (4) examine age differences, (5) develop common research tools to study alcohol-induced effects in clinical and pre-clinical studies, and (6) focus on factors that aggravate severity of organ-damage. The intention of these symposia is to advance the international profile of the biological research on alcoholism. We also wish to further our mission of leading the forum to progress the science and practice of translational research in alcoholism.


Translational Research | 2012

Genetic and immune predictors for hypersensitivity syndrome to antiepileptic drugs

Manuela G. Neuman; Lawrence B. Cohen; Radu M. Nanau; Paul A. Hwang

Hypersensitivity syndrome reactions (HSR) to antiepileptic drugs (AED) are associated with severe clinical cutaneous adverse reactions (SCAR). We aimed (1) to assess HSRs to AEDs using the in vitro lymphocyte toxicity assay (LTA) in patients who manifested HSRs clinically; (2) to correlate LTA results with the clinical syndrome; (3) to correlate LTA results with the human leukocyte antigen (HLA) allele B∗1502 (HLA-B∗1502) positivity in a Han Chinese-Canadian population; and (4) to determine the cytokine network in this population. Patients that developed fever and cutaneous eruptions in the presence or absence of organ involvement within 8 weeks of exposure to carbamazepine (CBZ), phenytoin (PHY), or lamotrigine (LTG) were enrolled. Control patients received AEDs without presenting HSR. We investigated 10 CBZ-HSR patients (4 with Stevens-Johnson syndrome [SJS]), 24 CBZ-controls, 10 PHY-HSR patients (4 with drug-induced liver injury [DILI]), 24 PHY-controls,6 LTG-HSR patients (1 with SJS and 1 with DILI), and 24 LTG-controls. There were 30 Han Chinese individuals (14 HSR patients and 16 controls) in our cohort. LTA toxicity greater than 12.5%±2.5% was considered positive. Differences among groups were determined by analysis of variance. In addition, we measured cytokine secretion in the patient sera between 1 month and 3 years after the event. All Han Chinese individuals and 30% of Caucasians were genotyped for HLA-B∗1502. A perfect correlation (r=0.92) was observed between positive LTA and clinical diagnosis of DILI and SJS/toxic epidermal necrolysis (TEN). HLA-B∗1502 positivity in Han Chinese is a predictor of CBZ-HSR and PHY-HSR. HLA-B∗1502-negative Han Chinese receiving only CBZ or a combination of CBZ and PHY tolerated the drug(s) clinically, presenting negative CBZ-LTA and PHY-LTA. However, 3 patients presenting negative CBZ-LTA and PHY-LTA, as well as negative HLA-B∗1502, showed positive LTG-LTA (38%, 28%, and 25%, respectively), implying that they should not be prescribed LTG. Three patients had LTA positive to both PHY and CBZ, and 3 others had LTA positive to both PHY and LTG. Clinically, all 6 patients presented HSR to both drugs that they tested positive to (cross-reactivity). Patients were grouped based on the clinical presentation of their symptoms as only rash and fever or as a triad of rash, fever and DILI or SJS/TEN that characterizes true HSR. Levels of proinflammatory cytokines were significantly higher in patient sera compared with control sera. More specifically, the highest levels of tumor necrosis factor-α have been measured in patients presenting true HSR, as were the apoptotic markers Fas, caspase 8 activity, and M30. The LTA is sensitive for DILI and SJS/TEN regardless of drug or patient ethnicity. HSR prediction will prevent AED-induced morbidity. In Han Chinese, HLA-B∗1502 positivity is a predictor for CBZ-HSR and PHY-HSR. Its negativity does not predict a negative LTG-HSR. There is cross-reactivity between AEDs. Additionally, T-cell cytokines and chemokines control the pathogenesis of SJS/TEN and DILI, contributing to apoptotic processes in the liver and in the skin.


Clinical Biochemistry | 2016

Hyaluronic acid as a non-invasive biomarker of liver fibrosis

Manuela G. Neuman; Lawrence B. Cohen; Radu M. Nanau

UNLABELLEDnChronic liver diseases may cause inflammation and progressive scarring, over time leading to irreversible hepatic damage (cirrhosis). As a result, the need to assess and closely monitor individuals for risk factors of components of matrix deposition and degradation, as well as the severity of the fibrosis using biomarkers, has been increasingly recognized.nnnAIMnOur aim is to review the use of biomarker for diagnosing and defining the severity of liver fibrosis.nnnMETHODSnA systematic literature review was done using the terms hyaluronic acid and liver fibrosis as well as the name of each biomarker or algorithm known to be employed. PubMed and Google Scholar were searched, and English language articles indexed between January 2010 and October 2014 in which HA was used as a marker of liver fibrosis were retrieved, regardless of the underlying liver disease. Each author read the publications separately and the results were analyzed and discussed.nnnRESULTSnBiomarkers offer a potential prognostic or diagnostic indicator for disease manifestation, progression, or both. Serum biomarkers, including HA, have been used for many years. Emerging biomarkers such as metalloproteinases have been proposed as tools that provide valuable complementary information to that obtained from traditional biomarkers. Moreover, markers of extracellular matrix degradation provide powerful predictions of risk. In order for biomarkers to be clinically useful in accurately diagnosing and treating disorders, age-specific reference intervals that account for differences in gender and ethnic origin are a necessity.nnnCONCLUSIONSnThis review attempts to provide a comprehensive analysis of the emerging risk biomarkers of liver fibrosis and to describe the clinical significance and analytical considerations of each biomarker pointing out sentinel features of disease progression.


Experimental and Molecular Pathology | 2015

Alcoholic liver disease: Clinical and translational research

Manuela G. Neuman; Stephen Malnick; Yaakov Maor; Radu M. Nanau; Ehud Melzer; Peter Ferenci; Helmut K. Seitz; Sebastian Mueller; Haim Mell; Didier Samuel; Lawrence B. Cohen; Kusum K. Kharbanda; Natalia A. Osna; Murali Ganesan; Kyle J. Thompson; Iain H. McKillop; Abraham Bautista; Ramon Bataller; Samuel W. French

The present review spans a broad spectrum of topics dealing with alcoholic liver disease (ALD), including clinical research, translational research, pathogenesis and therapies. A special accent is placed on alcohol misuse, as alcohol is a legally commercialized and taxable product. Drinking alcohol, particularly from a young age, is a major health problem. Alcoholism is known to contribute to morbidity and mortality. A systematic literature search was performed in order to obtain updated data (2008-2015). The review is focused on genetic polymorphisms of alcohol metabolizing enzymes and the role of cytochrome p450 2E1 and iron in ALD. Alcohol-mediated hepatocarcinogenesis is also discussed in the presence or absence of co-morbidities such as viral hepatitis C as well as therapeutic the role of innate immunity in ALD-HCV. Moreover, emphasis was placed on alcohol and drug interactions, as well as liver transplantation for end-stage ALD. Finally, the time came to eradicate alcohol-induced liver and intestinal damage by using betaine.


Annals of Pharmacotherapy | 1997

Pancreatic Insufficiency Due to Antituberculous Therapy

Barbara A. Liu; Sandra R. Knowles; Lawrence B. Cohen; Marsha R Werb; Neil H. Shear

OBJECTIVE: To describe a case of chronic pancreatic insufficiency related to antituberculous therapy. CASE SUMMARY: A 57-year-old man developed rash, fever, and hepatitis (aspartate aminotransferase 369 IU/L, alanine aminotransferase 506 IU/L), 6 weeks after starting isoniazid, rifampin, ethambutol, and pyrazinamide. He also developed severe metabolic acidosis secondary to diabetic ketoacidosis and lactic acidosis (serum bicarbonate 7 mEq/L, glucose 1778 mg/dL, and lactate 4.0 mEq/L). Acute pancreatitis was diagnosed on the basis of a mildly elevated amylase concentration (392 U/L) and radiologic evidence of pancreatic inflammation. He developed pancreatic insufficiency with steatorrhea and an abnormal secretin test. He continues to require pancreatic enzyme replacement and insulin therapy. Rechallenge was not performed. DISCUSSION: Hypersensitivity syndromes have been reported for various drug therapies, including antituberculous agents. Hypersensitivity syndrome reactions are characterized by fever, rash, and internal organ involvement. Rifampin has been reported to cause acute pancreatitis in up to 2.7% of patients. Drug-induced chronic pancreatitis, however, is reported to be extremely rare. This is the first reported case of chronic pancreatic insufficiency occurring in the setting of a hypersensitivity syndrome reaction to antituberculous drugs. CONCLUSIONS: Chronic pancreatic insufficiency should be considered as a possible long-term sequelae of a hypersensitivity syndrome reaction to antituberculous therapy.


Clinical Biochemistry | 2015

Quinolones-induced hypersensitivity reactions.

Manuela G. Neuman; Lawrence B. Cohen; Radu M. Nanau

UNLABELLEDnQuinolones are broad spectrum antibiotics that are intensively used and can induce immediate- and delayed-type hypersensitivity reactions, either IgE or T-cell mediated, in about 2-3% of treated patients.nnnOBJECTIVEnTo better understand how T cells interact with quinolones to produce the hypersensitivity and to describe the possible prevention of the reactions.nnnMETHODSnWe search in PubMed for quinolones and adverse reactions naming each one of the therapeutics in use and the possible hypersensitivity reactions e.g., anaphylaxis, drug-induced delayed reactions, and hypersensitivity syndrome reactions. We also performed a search on organ-specific hypersensitivity reactions including cutaneous reactions, hepatic reactions, and renal reactions.nnnRESULTSnOur data show that T cells are involved in delayed immune reactions to quinolones and that cross-reactivity among the different quinolones is frequent. The predictive tests for quinolone-induced hypersensitivity should be used in patients before they are given the medication.nnnCONCLUSIONSnEarly identification of the mechanism of toxicity, quantitative assessment using laboratory tests, analysis of risk factors for patient susceptibility to the quinolones, and possible drug-drug interactions may lead to appropriate patient selection for therapy, monitoring the injury early and discontinuation of the therapeutic agent.

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Neil H. Shear

Sunnybrook Health Sciences Centre

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Neil Rau

University of Toronto

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Sheldon M. Singh

Sunnybrook Health Sciences Centre

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Abraham Bautista

National Institutes of Health

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