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Dive into the research topics where John C. LeBlanc is active.

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Featured researches published by John C. LeBlanc.


Journal of Vascular and Interventional Radiology | 2002

Outcome and Prognostic Factors of Restenosis after Percutaneous Treatment of Native Hemodialysis Fistulas

Timothy W.I. Clark; David A. Hirsch; Kailash Jindal; Paul J. Veugelers; John C. LeBlanc

PURPOSE To assess patency after percutaneous treatment of dysfunctional and thrombosed native arteriovenous fistulas and to examine predictors of patency after intervention. MATERIALS AND METHODS A cohort of 65 consecutive patients with dysfunctional (n = 53) or occluded (n = 12) native fistulas who underwent 96 percutaneous interventions over an 18-month period was retrospectively analyzed. Fistula locations were radiocephalic (n = 37), brachiocephalic (n = 10), or brachiobasilic (n = 18). Primary interventions consisted of angioplasty (n = 50), stent placement (n = 3), or percutaneous thrombolysis/thrombectomy (n = 12). Additional interventions during follow-up consisted of angioplasty (n = 22), stent placement (n = 6), or percutaneous thrombolysis/thrombectomy (n = 3). Duration of fistula function was assessed clinically and examined as a function of anatomic and clinical variables with use of Cox hazards models and the Kaplan-Meier method. RESULTS Clinical success with resumption of at least one session of normal dialysis occurred in 94% (90 of 96) of interventions. The 30-day morbidity rate was 2.1%; no procedure-related deaths occurred. Primary, assisted primary, and secondary patency rates (+/- SE) of dysfunctional fistulas after intervention at 12 months were 26% +/- 11%, 80% +/- 6%, and 82% +/- 6%. Occluded fistulas after intervention had 3-month primary, assisted primary, and secondary patency rates of 60% +/- 15%, 60% +/- 15%, and 80% +/- 13%. Lesions 2.0 cm or more in length were five times more likely to have loss of patency than lesions smaller than 2.0 cm. The presence of at least one comorbid factor--diabetes, coronary artery disease, or peripheral vascular disease--was associated with nearly twice the risk of patency loss after any intervention. CONCLUSION Despite modest primary patency rates in our experience, high assisted and secondary patency rates can be achieved with percutaneous intervention in native arteriovenous fistulas. These findings emphasize the need for close surveillance of native fistulas and a low threshold for diagnostic fistulography after initial intervention. The most detrimental determinant of outcome was lesion length > or =2 cm.


Research in Human Development | 2008

The Study of Youth Resilience Across Cultures: Lessons from a Pilot Study of Measurement Development

Michael Ungar; Linda Liebenberg; Roger Boothroyd; Wai Man Kwong; Tak Yan Lee; John C. LeBlanc; Luis Fernando Duque; Alexander Makhnach

Resilience researchers from diverse disciplines and cultural settings face formidable challenges in conceptualizing and developing standardized metrics of resilience that are representative of adolescent and young adult experiences across cultures. We discuss these issues using the case example of a pilot study involving researchers in 14 sites in 11 countries. The goal of the International Resilience Project was to develop a culturally and contextually relevant measure of youth resilience, the Child and Youth Resilience Measure (CYRM). Cultural sensitivity and an iterative research design introduced to the study a number of problems that future studies of resilience will need to address: ambiguity in the definition of positive outcomes; a lack of predictability of models across cultures; and measurement design challenges.


The Journal of Infectious Diseases | 2003

Increasing Incidence of Hospitalization for Bronchiolitis among Canadian Children, 1980–2000

Joanne M. Langley; John C. LeBlanc; Bruce Smith; Elaine E. L. Wang

We evaluated temporal trends in hospitalization for bronchiolitis found among Canadian children for 1980-2000. The rate of hospital admission increased in all provinces over the 2 decades for all age groups but was highest in those aged <6 months. The mean length of stay decreased from 5.4 to 3.1 days (mean rate of decrease, 0.13 days/year; P<.0001). Because a concurrent increase in other respiratory diagnostic codes was not seen, it is unlikely that physician practice variation could explain this consistent trend over almost 2 decades, which may indicate a change in disease prevalence or severity.


Canadian Medical Association Journal | 2006

Home safety measures and the risk of unintentional injury among young children: a multicentre case–control study

John C. LeBlanc; I. Barry Pless; W. James King; Harry Bawden; Anne-Claude Bernard-Bonnin; Terry P. Klassen; Milton Tenenbein

Background: Young children may sustain injuries when exposed to certain hazards in the home. To better understand the relation between several childproofing strategies and the risk of injuries to children in the home, we undertook a multicentre case–control study in which we compared hazards in the homes of children with and without injuries. Methods: We conducted this case-control study using records from 5 pediatric hospital emergency departments for the 2-year period 1995–1996. The 351 case subjects were children aged 7 years and less who presented with injuries from falls, burns or scalds, ingestions or choking. The matched control subjects were children who presented during the same period with acute non-injury-related conditions. A home visitor, blinded to case-control status, assessed 19 injury hazards at the childrens homes. Results: Hazards found in the homes included baby walkers (21% of homes with infants), no functioning smoke alarm (17% of homes) and no fire extinguisher (51% of homes). Cases did not differ from controls in the mean proportion of home hazards. After controlling for siblings, maternal education and employment, we found that cases differed from controls for 5 hazards: the presence of a baby walker (odds ratio [OR] 9.0, 95% confidence interval [CI] 1.1–71.0), the presence of choking hazards within a childs reach (OR 2.0, 95% CI 1.0–3.7), no child-resistant lids in bathroom (OR 1.6, 95% CI 1.0–2.5), no smoke alarm (OR 3.2, 95% CI 1.4–7.7) and no functioning smoke alarm (OR 1.7, 95% CI 1.0–2.8). Interpretation: Homes of children with injuries differed from those of children without injuries in the proportions of specific hazards for falls, choking, poisoning and burns, with a striking difference noted for the presence of a baby walker. In addition to counselling parents about specific hazards, clinicians should consider that the presence of some hazards may indicate an increased risk for home injuries beyond those directly related to the hazard found. Families with any home hazard may be candidates for interventions to childproof against other types of home hazards.


Infection Control and Hospital Epidemiology | 2002

The role of Clostridium difficile and viruses as causes of nosocomial diarrhea in children

Joanne M. Langley; John C. LeBlanc; Martha Hanakowski; Olga Goloubeva

OBJECTIVE We report surveillance of nosocomial diarrhea in children at our institution during the past decade and note different epidemiology of diarrhea due to viruses and Clostridium difficile. DESIGN A prospective cohort study. SETTING A university-affiliated pediatric hospital with 180 beds serving an urban area and providing referral care for the Maritime Provinces of Canada. PARTICIPANTS Children younger than 18 years. METHODS Surveillance was conducted from 1991 to 1999 using personal contact with personnel and review of microbiology and medical records. Nosocomial diarrhea was defined as loose stools occurring more than 48 hours after admission, with at least two loose stools in 12 hours and no likely non-infectious cause. RESULTS Nosocomial diarrhea was the third most common nosocomial infection (217 of 1,466; 15%), after bloodstream and respiratory infections, with from 0.5 to 1 episode per 1,000 patient-days. Of 217 nosocomial diarrhea episodes, 122 (56%) had identified pathogens: C. difficile (39 of 122; 32%), rotavirus (38 of 122; 31%), adenovirus (36 of 122; 30%), and other viral (9 of 122; 7%). The median age was 1.3 years (range, 11 days to 17.9 years), 0.80 year for children with viral diarrhea, 3.9 years for children with C. difficile, and 1.5 years for children with diarrhea without a causative organism identified (P< .0001). Most children with nosocomial diarrhea were incontinent (diapered) at the time of their first episode (138 of 185; 75%), but preexisting incontinence was more common in those with viral diarrhea (93%) compared with those with no organism identified (71%) or those with C. difficile-associated diarrhea (CDAD) (49%) (P <.0001). CONCLUSIONS C. difficile is the single most common cause of nosocomial diarrhea in our tertiary-care center, although all viral pathogens account for 69% of cases. Diapered status appears to be a risk factor for CDAD in children, and CDAD occurs more often in older children than viral nosocomial diarrhea. Further characterization of risk factors for, and morbidity associated with, nosocomial CDAD in children is warranted.


Journal of Child and Adolescent Psychopharmacology | 2002

Screening for adolescent depression: comparison of the Kutcher Adolescent Depression Scale with the Beck depression inventory.

John C. LeBlanc; Anthony Almudevar; Sarah J. Brooks; Stan Kutcher

Self-report instruments commonly used to assess depression in adolescents have limited or unknown reliability and validity in this age group. We describe a new self-report scale, the Kutcher Adolescent Depression Scale (KADS), designed specifically to diagnose and assess the severity of adolescent depression. This report compares the diagnostic validity of the full 16-item instrument, brief versions of it, and the Beck Depression Inventory (BDI) against the criteria for major depressive episode (MDE) from the Mini International Neuropsychiatric Interview (MINI). Some 309 of 1,712 grade 7 to grade 12 students who completed the BDI had scores that exceeded 15. All were invited for further assessment, of whom 161 agreed to assessment by the KADS, the BDI again, and a MINI diagnostic interview for MDE. Receiver operating characteristic (ROC) curve analysis was used to determine which KADS items best identified subjects experiencing an MDE. Further ROC curve analyses established that the overall diagnostic ability of a six-item subscale of the KADS was at least as good as that of the BDI and was better than that of the full-length KADS. Used with a cutoff score of 6, the six-item KADS achieved sensitivity and specificity rates of 92% and 71%, respectively-a combination not achieved by other self-report instruments. The six-item KADS may prove to be an efficient and effective means of ruling out MDE in adolescents.


Biological Psychiatry | 2002

Temporal coherence in ultradian sleep EEG rhythms in a never-depressed, high-risk cohort of female adolescents.

Rachel Morehouse; Vivek Kusumakar; Stanley P. Kutcher; John C. LeBlanc; Roseanne Armitage

BACKGROUND Previous work has indicated that low temporal coherence of ultradian sleep electroencephalographic rhythms is characteristic of depressed patients and of depressed women, in particular. It may also be evident in one quarter of those at high risk, based on a family history of depression. METHODS The present study evaluated temporal coherence of sleep electroencephalographic rhythms in 41 adolescent girls with a maternal history of depression (high risk) and 40 healthy controls (low risk). The entire sample was followed clinically every 6 months for 2 years. RESULTS Temporal coherence was significantly lower among the high-risk girls than in controls. Regression analyses predicted group from coherence values and correctly classified 70% of the high-risk group with a false-positive rate of 5% among controls. Moreover, 54% of the high-risk girls were identified with extreme low coherence. On clinical follow up, 14 girls showed depressive symptoms, 9 in the high-risk group (22.5%) and 5 controls (12.2%). Six met DSM-IV criteria for first-episode major depressive disorder, five high-risk and one control. Most importantly, 41% of those identified as having the most abnormal coherence values either showed symptoms of depression or met diagnostic criteria upon follow up. CONCLUSIONS Low temporal coherence is evident in adolescent girls at high risk for depression. The more abnormal the coherence, the greater the risk of a first episode of major depressive disorder within 2 years of sleep study, approximately 10 times greater than in controls.


BMC Pediatrics | 2005

Racemic epinephrine compared to salbutamol in hospitalized young children with bronchiolitis; a randomized controlled clinical trial [ISRCTN46561076]

Joanne M. Langley; Michael B Smith; John C. LeBlanc; Heather Joudrey; Cecil Ojah; Paul Pianosi

BackgroundBronchiolitis is the most common cause of lower respiratory tract illness in infancy, and hospital admission rates appear to be increasing in Canada and the United States. Inhaled beta agonists offer only modest short-term improvement. Trials of racemic epinephrine have shown conflicting results. We sought to determine if administration of racemic epinephrine during hospital stay for bronchiolitis improved respiratory distress, was safe, and shortened length of stay.MethodsThe study was a randomized, double-blind controlled trial of aerosolized racemic epinephrine compared to salbutamol every one to 4 hours in previously well children aged 6 weeks to ≤ 2 years of age hospitalized with bronchiolitis. The primary outcome was symptom improvement as measured by the Respiratory Distress Assessment Instrument (RDAI); secondary outcomes were length of stay in hospital, adverse events, and report of symptoms by structured parental telephone interview one week after discharge.Results62 children with a mean age of 6.4 months were enrolled; 80% of children had Respiratory Syncytial Virus (RSV). Racemic epinephrine resulted in significant improvement in wheezing and the total RDAI score on day 2 and over the entire stay (p < 0.05). The mean LOS in the epinephrine arm was 2.6 days (95% CI 2, 3.2) v. 3.4 days in those in the salbutamol group (95% CI 2.6, 4.2) (p > 0.05). Adverse events were not significantly different in the two arms. At one week post-discharge, over half of parents reported that their child still had a respiratory symptom and 40% had less than normal feeding.ConclusionRacemic epinephrine relieves respiratory distress in hospitalized infants with bronchiolitis and is safe but does not abbreviate hospital stay. Morbidity associated with bronchiolitis as identified by parents persists for at least one week after hospital discharge in most infants.


Diagnostic Microbiology and Infectious Disease | 2000

Evaluation of four commercial transport media for the survival of Neisseria Gonorrhoeae

Judy C. Arbique; Kevin R. Forward; John C. LeBlanc

We evaluated four commercial transport systems with a standardized inoculum of clinical isolates of N. gonorrhoeae (NG), and assessed survival after holding for up to 48 hours at both ambient and refrigeration temperatures. Suspensions of clinical isolates of NG were standardized and adsorbed onto four transport swab types: Culturette EZ (Becton Dickinson [BD], Cockeysville, MD, USA); Cultureswab (Difco Laboratories, Detroit, MI, USA); Venturi Transystem (Copan Italia, Bovezzo, Italy); and a recently modified Starswab (Starplex Scientific, Etobicoke, ON). Swabs were plated to chocolate agar at 0, 6, 24, and 48 hours, and colonies counted. Each swab type was tested in quadruplicate with each NG strain for all time and temperature variables. There was a marked reduction in NG CFUs after only 6 hours incubation with each of the swabs tested. Survival was best using Venturi Transystem and Cultureswab transports (colony counts were reduced to 15.3% and 13.0%, respectively, at 6 hours) when compared with the Culturette EZ and Starswab (colony counts were reduced to 2.2% and 4.3%, respectively, at 6 hours). After the 24-hour holding period, 94% of the cultures from the Venturi Transystem were positive, 82% from the Cultureswab, 24% from the Starswab; and 17% from the Culturette EZ. After 48 hours, recovery dropped to 72%, 43%, 14%, and 0.04%, respectively. All of the systems tested had at least an 80% decrease in recovered colonies after only 6 hours. Further studies are required to determine how poor transport conditions influence the number of positive cultures and what the public health implications are. Of the swabs tested, Cultureswab and Venturi Transystem were most acceptable.


Progress in Neuro-psychopharmacology & Biological Psychiatry | 2002

A randomized trial of a specific adherence enhancement program in sertraline-treated adults with major depressive disorder in a primary care setting

Stan Kutcher; John C. LeBlanc; Connie Maclaren; Vratislav Hadrava

Adherence to drug therapy is a limitation in treatment success for major depressive disorder (MDD). The influence of RHYTHMS, an information and ongoing interactive program designed by Pfizer Pharmaceuticals, to address patient adherence to sertraline therapy was evaluated in a primary care setting using a randomized, double-blind, parallel group controlled trial over 29 weeks. Remission was the primary outcome evaluated. At study completion, no statistically significance between group differences was noted for remission rates, treatment adherence or mean Hamilton Depression Rating Scale (HDRS) score. However, the RHYTHMS group reported significantly greater satisfaction with knowledge received about depression and its treatment and demonstrated significantly greater satisfaction with treatment received. We conclude that the application of RHYTHMS in a primary care setting has a substantial role in improving satisfaction with sertraline treatment by patients with MDD.

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A. McGeer

University of Toronto

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