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Featured researches published by Dion Pasichnyk.


Annals of Internal Medicine | 2012

Antipsychotics in Adults With Schizophrenia: Comparative Effectiveness of First-Generation Versus Second-Generation Medications: A Systematic Review and Meta-analysis

Lisa Hartling; Ahmed M Abou-Setta; Serdar Dursun; Shima S Mousavi; Dion Pasichnyk; Amanda S. Newton

BACKGROUND Debate continues about the comparative benefits and harms of first-generation antipsychotics (FGAs) and second-generation antipsychotics (SGAs) in treating schizophrenia. PURPOSE To compare the effects of FGAs with those of SGAs in the treatment of adults aged 18 to 64 years with schizophrenia and related psychosis on illness symptoms, diabetes mellitus, mortality,tardive dyskinesia, and a major metabolic syndrome. DATA SOURCES English-language studies from 10 electronic databases to March 2012, reference lists of relevant articles, and gray literature. STUDY SELECTION Randomized trials for efficacy and cohort studies at least 2 years in duration for adverse events. DATA EXTRACTION Two independent reviewers extracted data from 114 studies involving 22 comparisons and graded the strength of evidence for primary outcomes as insufficient, low, moderate, or high using the Grading of Recommendations Assessment, Development and Evaluation approach. DATA SYNTHESIS Few differences of clinical importance were found for core illness symptoms; lack of precision in effect estimates precluded firm conclusions for many comparisons. Moderate-strength evidence showed a clinically important benefit of haloperidol over olanzapine for improving positive symptoms, but the benefit was scale-dependent: It was seen when the Scale for the Assessment of Positive Symptoms was used but not when the Positive and Negative Syndrome Scale (PANSS) was used. Moderate-strength evidence showed a clinically important benefit of olanzapine over haloperidol in improving negative symptoms when the PANSS and the Scale for the Assessment of Negative Symptoms were used. Low-strength evidence showed no difference in mortality for chlorpromazine verus clozapine or haloperidol versus aripiprazole,increased incidence of the metabolic syndrome for olanzapine versus haloperidol (risk differences, 2% and 22%), and higher incidence of tardive dyskinesia for chlorpromazine versus clozapine (risk differences, 5% and 9%). Evidence was insufficient to draw conclusions for diabetes mellitus. LIMITATIONS All studies had high or unclear risk of bias. Length of study follow-up was often too brief to adequately measure adverse events. Medication comparisons, dosage, and outcome measurement were heterogenous for head-to-head comparisons. Selective patient populations limit generalizability. CONCLUSION Clear benefits of FGAs versus SGAs for treating schizophrenia remain inconclusive because of variation in assessing outcomes and lack of clinically important differences for most comparisons. The strength of evidence on safety for major medical events is low or insufficient. PRIMARY FUNDING SOURCE Agency for Healthcare Research and Quality.


Journal of Immunology | 2011

Granule-Derived Granzyme B Mediates the Vulnerability of Human Neurons to T Cell-Induced Neurotoxicity

Yohannes Haile; Katia Simmen; Dion Pasichnyk; Nicolas Touret; Thomas Simmen; Jian-Qiang Lu; R. Chris Bleackley; Fabrizio Giuliani

Multiple sclerosis (MS) is considered an autoimmune disease of the CNS and is characterized by inflammatory cells infiltrating the CNS and inducing demyelination, axonal loss, and neuronal death. Recent evidence strongly suggests that axonal and neuronal degeneration underlie the progression of permanent disability in MS. In this study, we report that human neurons are selectively susceptible to the serine-protease granzyme B (GrB) isolated from cytotoxic T cell granules. In vitro, purified human GrB induced neuronal death to the same extent as the whole activated T cell population. On the contrary, activated T cells isolated from GrB knockout mice failed to induce neuronal injury. We found that following internalization through various parts of neurons, GrB accumulated in the neuronal soma. Within the cell body, GrB diffused out of endosomes possibly through a perforin-independent mechanism and induced subsequent activation of caspases and cleavage of α-tubulin. Inhibition of caspase-3, a well-known substrate for GrB, significantly reduced GrB-mediated neurotoxicity. We demonstrated that treatment of neurons with mannose-6-phosphate prevented GrB entry and inhibited GrB-mediated neuronal death, suggesting mannose-6-phosphate receptor-dependent endocytosis. Together, our data unveil a novel mechanism by which GrB induces selective neuronal injury and suggest potential new targets for the treatment of inflammatory-mediated neurodegeneration in diseases such as MS.


PLOS ONE | 2015

Gastroenteritis Therapies in Developed Countries: Systematic Review and Meta-Analysis

Stephen B. Freedman; Dion Pasichnyk; Karen J. L. Black; Eleanor Fitzpatrick; Serge Gouin; Andrea Milne; Lisa Hartling

Context Gastroenteritis remains a leading cause of childhood morbidity. Objective Because prior reviews have focused on isolated symptoms and studies conducted in developing countries, this study focused on interventions commonly considered for use in developed countries. Intervention specific, patient-centered outcomes were selected. Data Sources MEDLINE, EMBASE, the Cochrane Database of Systematic Reviews, trial registries, grey literature, and scientific meetings. Study Selection Randomized controlled trials, conducted in developed countries, of children aged <18 years, with gastroenteritis, performed in emergency department or outpatient settings which evaluated oral rehydration therapy (ORT), antiemetics, probiotics or intravenous fluid administration rate. Data Extraction The study was conducted in accordance with the Cochrane Handbook for Systematic Reviews of Interventions and the PRISMA guidelines. Data were independently extracted by multiple investigators. Analyses employed random effects models. Results 31 trials (4,444 patients) were included. ORT: Compared with intravenous rehydration, hospitalization (RR 0.80, 95%CI 0.24, 2.71) and emergency department return visits (RR 0.86, 95%CI 0.39, 1.89) were similar. Antiemetics: Fewer children administered an antiemetic required intravenous rehydration (RR 0.40, 95%CI 0.26, 0.60) While the data could not be meta-analyzed, three studies reported that ondansetron administration does increase the frequency of diarrhea. Probiotics: No studies reported on the primary outcome, three studies evaluated hospitalization within 7 days (RR 0.87, 95%CI 0.25, 2.98). Rehydration: No difference in length of stay was identified for rapid vs. standard intravenous or nasogastric rehydration. A single study found that 5% dextrose in normal saline reduced hospitalizations compared with normal saline alone (RR 0.70, 95% CI 0.53, 0.92). Conclusions There is a paucity of patient-centered outcome evidence to support many interventions. Since ORT is a low-cost, non-invasive intervention, it should continue to be used. Routine probiotic use cannot be endorsed at this time in outpatient children with gastroenteritis. Despite some evidence that ondansetron administration increases diarrhea frequency, emergency department use leads to reductions in intravenous rehydration and hospitalization. No benefits were associated with ondansetron use following emergency department discharge.


Environmental Health | 2011

A retrospective cohort study of stroke onset: implications for characterizing short term effects from ambient air pollution

Julie Y.M. Johnson; Paul J. Villeneuve; Dion Pasichnyk; Brian H. Rowe

BackgroundCase-crossover studies used to investigate associations between an environmental exposure and an acute health response, such as stroke, will often use the day an individual presents to an emergency department (ED) or is admitted to hospital to infer when the stroke occurred. Similarly, they will use patients place of residence to assign exposure. The validity of using these two data elements, typically extracted from administrative databases or patient charts, to define the time of stroke onset and to assign exposure are critical in this field of research as air pollutant concentrations are temporally and spatially variable. Our a priori hypotheses were that date of presentation differs from the date of stroke onset for a substantial number of patients, and that assigning exposure to ambient pollution using place of residence introduces an important source of exposure measurement error. The objective of this study was to improve our understanding on how these sources of errors influence risk estimates derived using a case-crossover study design.MethodsWe sought to collect survey data from stroke patients presenting to hospital EDs in Edmonton, Canada on the date, time, location and nature of activities at onset of stroke symptoms. The daily mean ambient concentrations of NO2 and PM2.5 on the self-reported day of stroke onset was estimated from continuous fixed-site monitoring stations.ResultsOf the 336 participating patients, 241 were able to recall when their stroke started and 72.6% (95% confidence interval [CI]: 66.9 - 78.3%) experienced stroke onset the same day they presented to the ED. For subjects whose day of stroke onset differed from the day of presentation to the ED, this difference ranged from 1 to 12 days (mean = 1.8; median = 1). In these subjects, there were no systematic differences in assigned pollution levels for either NO2 or PM2.5 when day of presentation rather than day of stroke onset was used. At the time of stroke onset, 89.9% (95% CI: 86.6 - 93.1%) reported that they were inside, while 84.5% (95% CI: 80.6 - 88.4%) reported that for most of the day they were within a 15 minute drive from home. We estimated that due to the mis-specification of the day of stroke onset, the risk of hospitalization for stroke would be understated by 15% and 20%, for NO2 and PM2.5, respectively.ConclusionsOur data suggest that day of presentation and residential location data obtained from administrative records reasonably captures the time and location of stroke onset for most patients. Under these conditions, any associated errors are unlikely to be an important source of bias when estimating air pollution risks in this population.


PLOS ONE | 2017

Correction: Gastroenteritis Therapies in Developed Countries: Systematic Review and Meta-Analysis

Stephen B. Freedman; Dion Pasichnyk; Karen J. L. Black; Eleanor Fitzpatrick; Serge Gouin; Andrea Milne; Lisa Hartling

[This corrects the article DOI: 10.1371/journal.pone.0128754.].


Evidence Report/Technology Assessment | 2012

Screening and diagnosing gestational diabetes mellitus.

Lisa Hartling; Donna M Dryden; Alyssa Guthrie; Melanie Muise; Ben Vandermeer; Walie M Aktary; Dion Pasichnyk; Jennifer C Seida; Lois E. Donovan


Science of The Total Environment | 2012

Short-term effects of ambient air pollution on stroke: who is most vulnerable?

Paul J. Villeneuve; Julie Y.M. Johnson; Dion Pasichnyk; Justin Lowes; Scott W. Kirkland; Brian H. Rowe


Physical Therapy | 2014

Identifying Items to Assess Methodological Quality in Physical Therapy Trials: A Factor Analysis

Greta G. Cummings; Jorge Fuentes; Humam Saltaji; Christine Ha; Annabritt Chisholm; Dion Pasichnyk; Todd Rogers


Archive | 2012

List of Companion Studies

Ahmed M Abou-Setta; Shima S Mousavi; Carol Spooner; Janine R Schouten; Dion Pasichnyk; Amy Beaith; Jennifer C Seida; Serdar Dursun; Amanda S. Newton; Lisa Hartling


Archive | 2012

Forest plot 6, Haloperidol versus olanzapine–Withdrawal due to adverse events

Ahmed M Abou-Setta; Shima S Mousavi; Carol Spooner; Janine R Schouten; Dion Pasichnyk; Amy Beaith; Jennifer C Seida; Serdar Dursun; Amanda S. Newton; Lisa Hartling

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Brian H. Rowe

University of Alberta Hospital

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