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Dive into the research topics where Ronald M. Laxer is active.

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Featured researches published by Ronald M. Laxer.


Arthritis Care and Research | 2011

2011 American College of Rheumatology Recommendations for the Treatment of Juvenile Idiopathic Arthritis: Initiation and Safety Monitoring of Therapeutic Agents for the Treatment of Arthritis and Systemic Features

Timothy Beukelman; Nivedita M. Patkar; Kenneth G. Saag; Sue Tolleson-Rinehart; Randy Q. Cron; Esi Morgan DeWitt; Norman T. Ilowite; Yukiko Kimura; Ronald M. Laxer; Daniel J. Lovell; Alberto Martini; C. Egla Rabinovich; Nicolino Ruperto

Guidelines and recommendations developed and/or endorsed by the American College of Rheumatology (ACR) are intended to provide guidance for particular patterns of practice and not to dictate the care of a particular patient. The ACR considers adherence to these guidelines and recommendations to be voluntary, with the ultimate determination regarding their application to be made by the physician in light of each patient’s individual circumstances. Guidelines and recommendations are intended to promote beneficial or desirable outcomes but cannot guarantee any specific outcome. Guidelines and recommendations developed or endorsed by the ACR are subject to periodic revision as warranted by the evolution of medical knowledge, technology, and practice.


Nature Genetics | 2014

An activating NLRC4 inflammasome mutation causes autoinflammation with recurrent macrophage activation syndrome

Scott W. Canna; Adriana A. Jesus; Sushanth Gouni; Stephen R. Brooks; Bernadette Marrero; Yin Liu; Michael A. DiMattia; Kristien J M Zaal; Gina A. Montealegre Sanchez; Hanna Kim; Dawn Chapelle; Nicole Plass; Yan Huang; Alejandro V. Villarino; Angélique Biancotto; Thomas A. Fleisher; Joseph A. Duncan; John J. O'Shea; Susanne M. Benseler; Alexei A. Grom; Zuoming Deng; Ronald M. Laxer; Raphaela Goldbach-Mansky

Inflammasomes are innate immune sensors that respond to pathogen- and damage-associated signals with caspase-1 activation, interleukin (IL)-1β and IL-18 secretion, and macrophage pyroptosis. The discovery that dominant gain-of-function mutations in NLRP3 cause the cryopyrin-associated periodic syndromes (CAPS) and trigger spontaneous inflammasome activation and IL-1β oversecretion led to successful treatment with IL-1–blocking agents. Herein we report a de novo missense mutation (c.1009A>T, encoding p.Thr337Ser) affecting the nucleotide-binding domain of the inflammasome component NLRC4 that causes early-onset recurrent fever flares and macrophage activation syndrome (MAS). Functional analyses demonstrated spontaneous inflammasome formation and production of the inflammasome-dependent cytokines IL-1β and IL-18, with the latter exceeding the levels seen in CAPS. The NLRC4 mutation caused constitutive caspase-1 cleavage in cells transduced with mutant NLRC4 and increased production of IL-18 in both patient-derived and mutant NLRC4–transduced macrophages. Thus, we describe a new monoallelic inflammasome defect that expands the monogenic autoinflammatory disease spectrum to include MAS and suggests new targets for therapy.


The Journal of Pediatrics | 2000

Methotrexate and corticosteroid therapy for pediatric localized scleroderma

Yosef Uziel; Brian M. Feldman; Bernice R. Krafchik; Rae S. M. Yeung; Ronald M. Laxer

INTRODUCTION Localized scleroderma (LS) can cause permanent disability, and there is no universally accepted effective treatment. Methotrexate (MTX) has been shown to be effective in the treatment of systemic sclerosis. OBJECTIVES To determine the efficacy and tolerability of MTX and corticosteroid therapy in patients with LS. METHODS MTX, 0.3 to 0.6 mg/kg per week, was given to 10 patients (6 girls, 4 boys; mean age, 6.8 years; mean disease duration before starting treatment, 4 years) with active LS. In addition, pulse intravenous methylprednisolone, 30 mg/kg for 3 days monthly for 3 months, was given to 9 patients at the initiation of therapy. RESULTS One patient discontinued taking MTX after a month; the remaining 9 patients responded. The median time to response was 3 months (95% CI, 1.15-4.85). One responder discontinued taking MTX after a year because of leukopenia; the LS worsened within 2 months. In another patient LS flared up after 10 months and responded to an increased dose of MTX and intravenous methylprednisolone. At the last follow-up visit, all patients who continued to receive MTX therapy had inactive skin lesions. CONCLUSION Treatment with MTX and corticosteroids appears to be effective in the treatment of LS and is generally well tolerated. A placebo-controlled study is necessary to confirm the efficacy of MTX therapy in LS.


The American Journal of Medicine | 1991

Treatment of dermatomyositis with intravenous gammaglobulin

Bianca A. Lang; Ronald M. Laxer; Gordon Murphy; Earl D. Silverman; Chaim M. Roifman

PURPOSE The mainstay of pharmacologic therapy in patients with dermatomyositis is corticosteroids. However, because patients sometimes become refractory to these drugs and because these drugs have potential short- and long-term toxicities, alternate therapy is highly desirable. Therefore, a pilot study was initiated using high-dose intravenous gammaglobulin (IVGG) in the treatment of dermatomyositis. PATIENTS AND METHODS IVGG was administered to five patients with juvenile dermatomyositis. Prior to IVGG treatment, all patients had persistent muscle weakness despite daily corticosteroids and three patients had developed unacceptable steroid toxicity. Two of the patients had previously developed toxicity while receiving immunosuppressive therapy. RESULTS IVGG therapy resulted in improved muscle strength and ameliorated skin rash in all patients. The percentage increase in muscle strength as measured by sphygmomanometry following the 9-month course of IVGG ranged from 56% to 606% in the proximal lower extremities and from 30% to 186% in the proximal upper extremities. Following IVGG therapy, prednisone could be discontinued or the dose reduced in all patients. CONCLUSION This study suggests that IVGG may allow steroid sparing in dermatomyositis and may provide a safe alternative to cytotoxic therapy.


Arthritis & Rheumatism | 2013

2013 Update of the 2011 American College of Rheumatology Recommendations for the Treatment of Juvenile Idiopathic Arthritis: Recommendations for the Medical Therapy of Children With Systemic Juvenile Idiopathic Arthritis and Tuberculosis Screening Among Children Receiving Biologic Medications

Sarah Ringold; Pamela F. Weiss; Timothy Beukelman; Esi Morgan DeWitt; Norman T. Ilowite; Yukiko Kimura; Ronald M. Laxer; Daniel J. Lovell; Peter Nigrovic; Angela Byun Robinson; Richard K. Vehe

Guidelines and recommendations developed and/or endorsed by the American College of Rheumatology (ACR) are intended to provide guidance for particular patterns of practice and not to dictate the care of a particular patient. The ACR considers adherence to these guidelines and recommendations to be voluntary, with the ultimate determination regarding their application to be made by the physician in light of each patients individual circumstances. Guidelines and recommendations are intended to promote beneficial or desirable outcomes but cannot guarantee any specific outcome. Guidelines and recommendations developed or endorsed by the ACR are subject to periodic revision as warranted by the evolution of medical knowledge, technology, and practice.The American College of Rheumatology is an independent, professional, medical and scientific society which does not guarantee, warrant, or endorse any commercial product or service.


Pediatric Neurology | 1995

Neurologic manifestations of pediatric systemic lupus erythematosus.

Maja Steinlin; Susan Blaser; David L. Gilday; Allison A. Eddy; William J. Logan; Ronald M. Laxer; Earl D. Silverman

Central nervous system involvement is a common but rarely reviewed feature of pediatric systemic lupus erythematosus (SLE). We retrospectively reviewed the charts of 91 patients with pediatric SLE and using a standardized data abstraction form documented 40 patients with central nervous system (CNS-SLE) involvement. The mean age of onset of SLE was 13.3 years. In 19 patients the CNS manifestation was a presenting symptom, in 12 patients CNS involvement was present within the first year of diagnosis, and in 9 patients it took up to 7 years for CNS disease to become evident. Nineteen children (48%) manifested neuropsychiatric SLE, which included depression, concentration or memory problems, and frank psychosis. Seizures were present in 8 patients (20%), 6 had cerebral ischemic events (15%), 1 had chorea (3%), 2 had papilledema (5%), and 2 patients had a peripheral neuropathy (5%). Nine patients (22%) had severe headache consistent with lupus headache. Seven children had more than one CNS manifestation. In the investigation of CNS-SLE, computed tomography and/or magnetic resonance imaging scans were helpful in patients with focal ischemic lesions and venous sinus thrombosis. Electroencephalography was abnormal only in 33% of patients with seizure disorders and rarely helpful in patients with diffuse neuropsychiatric symptoms. Single-photon emission computed tomography scans were abnormal in most patients with neuropsychiatric SLE, especially in those with frank psychosis. The lupus anticoagulant was present in the patient with chorea and was frequently present in patients with cerebral vascular events. Long-term outcome was good: only 1 child died of cerebral hemorrhagic infarction and 3 others had significant persistent CNS deficits. The majority of patients (90%) had excellent recovery from CNS-SLE.


Nature Genetics | 2016

Loss-of-function mutations in TNFAIP3 leading to A20 haploinsufficiency cause an early-onset autoinflammatory disease

Qing Zhou; Hongying Wang; Daniella M. Schwartz; Monique Stoffels; Yong Hwan Park; Yuan Zhang; Dan Yang; Erkan Demirkaya; Masaki Takeuchi; Wanxia Li Tsai; Jonathan J. Lyons; Xiaomin Yu; Claudia Ouyang; Celeste Chen; David T. Chin; Kristien Zaal; Settara C. Chandrasekharappa; Eric P. Hanson; Zhen Yu; James C. Mullikin; Sarfaraz Hasni; Ingrid E Wertz; Amanda K. Ombrello; Deborah L. Stone; Patrycja Hoffmann; Anne Jones; Beverly Barham; Helen L. Leavis; Annet van Royen-Kerkof; Cailin Sibley

Systemic autoinflammatory diseases are driven by abnormal activation of innate immunity. Herein we describe a new disease caused by high-penetrance heterozygous germline mutations in TNFAIP3, which encodes the NF-κB regulatory protein A20, in six unrelated families with early-onset systemic inflammation. The disorder resembles Behçets disease, which is typically considered a polygenic disorder with onset in early adulthood. A20 is a potent inhibitor of the NF-κB signaling pathway. Mutant, truncated A20 proteins are likely to act through haploinsufficiency because they do not exert a dominant-negative effect in overexpression experiments. Patient-derived cells show increased degradation of IκBα and nuclear translocation of the NF-κB p65 subunit together with increased expression of NF-κB–mediated proinflammatory cytokines. A20 restricts NF-κB signals via its deubiquitinase activity. In cells expressing mutant A20 protein, there is defective removal of Lys63-linked ubiquitin from TRAF6, NEMO and RIP1 after stimulation with tumor necrosis factor (TNF). NF-κB–dependent proinflammatory cytokines are potential therapeutic targets for the patients with this disease.


Arthritis & Rheumatism | 2000

Early predictors of poor functional outcome in systemic‐onset juvenile rheumatoid arthritis: A multicenter cohort study

Lynn Spiegel; Rayfel Schneider; Bianca A. Lang; Nina Birdi; Earl D. Silverman; Ronald M. Laxer; Derek Stephens; Brian M. Feldman

OBJECTIVE To examine the ability of a previously described set of criteria to predict poor functional outcome in a large, multicenter cohort of children with systemic-onset juvenile rheumatoid arthritis (JRA). METHODS All children who were diagnosed with systemic-onset JRA since 1980 at the Hospital for Sick Children (Toronto), since 1983 at the Isaac Walton Killam Hospital for Children (Halifax), and since 1981 at the Childrens Hospital of Eastern Ontario (Ottawa) were evaluated. Patients were included in the study if they had been evaluated clinically within 6 months of diagnosis and had been followed up for at least 2 years. Patients were divided into 4 cohorts according to their length of followup: 2-4 years, 4-7 years, 7-10 years, and >10 years. Using previously described criteria for destructive arthritis in children with systemic-onset JRA, the patients were classified as either high risk or low risk for poor functional outcome based on the data from their 6-month visit. High-risk patients had active systemic disease (persistent fever or corticosteroid requirement for control of systemic disease) and a platelet count > or =600 x 10(9)/liter. Poor outcome was defined as moderate or severe disability (defined as a score of > or =0.75 on the Childhood Health Assessment Questionnaire) or disease-associated death. RESULTS Among 122 eligible patients with systemic-onset JRA, we were able to contact 111 (91%) for outcome data. The mean followup period was 7.7 years (SD 3.7). The mean age at outcome assessment was 13.5 years (SD 5.3). There were 51 boys and 60 girls. Twenty-four patients (22%) had moderate-to-severe disability and 2 patients died; these 26 patients were considered to have had a poor outcome. We could determine risk classification for 104 patients. Twenty-four patients (23%) met the criteria for high risk at the 6-month visit. Overall, the risk of a poor functional outcome was significantly higher in the high-risk group (relative risk 3.3, 95% confidence interval [95% CI] 1.73-6.43, P = 0.0004). This risk was most marked in the cohort with > 10 years of followup (relative risk 4.3, 95% CI 1.82-10.29, P = 0.006). CONCLUSION The presence of active systemic disease at 6 months, as characterized by fever or the need for corticosteroids, and thrombocytosis strongly predicted the development of a poor functional outcome in these patients. This was especially apparent with longterm followup. Our study validates the previously developed prognostic criteria for systemic-onset JRA.


Pediatric Infectious Disease Journal | 1987

Chronic recurrent multifocal osteomyelitis: a noninfectious inflammatory process

Susan M. King; Ronald M. Laxer; D. Manson; Ronald Gold

We report seven patients with chronic recurrent multifocal osteomyelitis, an uncommon childhood disease of unknown etiology. These patients presented with insidious onset of bone pain at one or more sites associated with erythema, swelling and tenderness. Scintigraphy and radiography were consistent with osteomyelitis at multiple sites. Bone biopsies confirmed osteomyelitis but no organisms were consistently isolated. During a 1- to 3-year follow-up, most patients developed new symptomatic lesions. The disease was unaffected by antimicrobial therapy. Two of our patients had psoriasis and all were rheumatoid factor-, antinuclear factor- and HLA-B27-negative. We speculate that chronic recurrent osteomyelitis is a noninfectious inflammatory condition, a seronegative spondyloarthropathy. Chronic recurrent osteomyelitis is a clinical entity that should be recognized so that invasive diagnostic procedures and antimicrobial therapy are appropriately used. The patient may be reassured that this is not a malignant condition although there may be exacerbations over many years.


Arthritis Care and Research | 2008

Feasibility and effectiveness of an aerobic exercise program in children with fibromyalgia: results of a randomized controlled pilot trial.

Samantha Stephens; Brian M. Feldman; Nicolette Bradley; Jane E. Schneiderman; Virginia Wright; Davinder Singh-Grewal; Arlette Lefebvre; Susanne M. Benseler; Bonnie Cameron; Ronald M. Laxer; Christine O'brien; Rayfel Schneider; Earl D. Silverman; Lynn Spiegel; Jennifer Stinson; Pascal N. Tyrrell; Kristi Whitney; Shirley M. L. Tse

OBJECTIVE To determine the feasibility of conducting a randomized controlled trial of a 12-week exercise intervention in children with fibromyalgia (FM) and to explore the effectiveness of aerobic exercise on physical fitness, function, pain, FM symptoms, and quality of life (QOL). METHODS FM patients ages 8-18 years were randomized to a 12-week exercise intervention of either aerobics or qigong. Both groups participated in 3 weekly training sessions. Program adherence and safety were monitored at each session. Data were collected at 3 testing sessions, 2 prior to and 1 after the intervention, and included FM symptoms, function, pain, QOL, and fitness measures. RESULTS Thirty patients participated in the trial. Twenty-four patients completed the program; 4 patients dropped out prior to training and 2 dropped out of the aerobics program. Better adherence was reported in the aerobics group than in the qigong group (67% versus 61%). Significant improvements in physical function, functional capacity, QOL, and fatigue were observed in the aerobics group. Anaerobic function, tender point count, pain, and symptom severity improved similarly in both groups. CONCLUSION It is feasible to conduct an exercise intervention trial in children with FM. Children with FM tolerate moderate-intensity exercise without exacerbation of their disease. Significant improvements in physical function, FM symptoms, QOL, and pain were demonstrated in both exercise groups; the aerobics group performed better in several measures compared with the qigong group. Future studies may need larger sample sizes to confirm clinical improvement and to detect differences in fitness in childhood FM.

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Philip J. Hashkes

Shaare Zedek Medical Center

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