Papers by François Proulx
Clinical and Experimental Immunology, 2003
SUMMARY Mannan-binding lectin (MBL) triggers complement activation upon binding to microbial surf... more SUMMARY Mannan-binding lectin (MBL) triggers complement activation upon binding to microbial surfaces. MBL deficiency has been associated with increased susceptibility to severe bacterial infections. We hypothesized that MBL deficiency may predispose children to Shiga toxin-producing Escherichia coli (STEC) O157:H7 infections and the associated haemolytic uraemic syndrome (HUS). We compared circulating levels of MBL among children with uncomplicated O157:H7 haemorrhagic colitis (HC), patients with O157:H7 HUS, normal and diseases control groups. Circulating MBL concentrations on admission were as follows: 3·22 ± 2·43 µg/ml among normal controls (n = 23); 2·90 ± 2·44 µg/ml in patients with rotavirus enteritis (n = 10); 2·78 ± 1·65 µg/ml in children with HC due to non-STEC bacterial pathogen (n = 15); 2·67 ± 2·44 µg/ml in patients with uncomplicated O157:H7 HC (n = 27); 2·80 ± 2·97 µg/ml in children with O157:H7 HUS (n = 15); 6·70 ± 4·49 µg/ml in patients with chronic renal failure un...
Respiratory care, Jan 2, 2016
High-flow nasal cannula (HFNC) therapy is increasingly used in pediatric ICUs as an intermediate ... more High-flow nasal cannula (HFNC) therapy is increasingly used in pediatric ICUs as an intermediate level of support between conventional oxygen delivery and noninvasive ventilation (NIV). The safety of HFNC has seldom been studied, and some cases of barotrauma have been reported. This retrospective study aims to describe HFNC use in a tertiary care pediatric ICU, with a focus on the complications associated with this therapy. Between January 2013 and January 2014, all children <18 y old treated with HFNC in the pediatric ICU were included. Demographic data, HFNC settings, chest radiograph reports, and blood gas values were gathered from the electronic medical records. Episodes of pneumothorax, pneumomediastinum, and significant epistaxis were noted. Pneumothorax was distinguished from chest tube-related air leak (frequent after cardiac surgery), which was defined as a small pneumothorax with no clinical impact that resolved spontaneously after chest tube removal. During the 1-y stu...
Blood, 2007
Thrombotic microangiopathy and acute renal failure are cardinal features of postdiarrheal hemolyt... more Thrombotic microangiopathy and acute renal failure are cardinal features of postdiarrheal hemolytic uremic syndrome (HUS). These conditions are related to endothelial and epithelial cell damage induced by Shiga toxin (Stx) through the interaction with its globotriaosyl ceramide receptor. However, inflammatory processes contribute to the pathogenesis of HUS by sensitizing cells to Stx fractalkine (FKN), a CX3C transmembrane chemokine expressed on epithelial and endothelial cells upon activation, is involved in the selective migration and adhesion of specific leukocyte subsets to tissues. Here, we demonstrated a selective depletion of circulating mononuclear leukocytes expressing the receptor for FKN (CX3CR1) in patients with HUS. We found a unique phenotype in children with HUS distinct from that seen in healthy, uremic, or infected controls, in which monocytes lost CX3CR1, down-modulated CD62L, and increased CD16. In addition, the CD56dim natural killer (NK) subpopulation was decrea...
Chest Journal, Aug 1, 1997
Journal for Nature Conservation, 2016
Pediatric Nephrology, 1999
Experimental data suggest that the host's inflammatory response is involved in the pathophysiolog... more Experimental data suggest that the host's inflammatory response is involved in the pathophysiology of verotoxin-producing Escherichia coli (VTEC)-associated hemolytic uremic syndrome (HUS). We compared the circulating levels of pro-[interleukin (IL)-6, IL-8] and anti-inflammatory [IL-10 and IL-1 receptor antagonist (Ra)] mediators on enrollment among children with HUS due to E. coli O157:H7, according to the severity of renal dysfunction. The latter was evaluated by the occurrence of oligoanuria, the requirement for dialysis, and a glomerular filtration rate (GFR) ≤80 ml/min per 1.73 m 2 measured 1 year later. Increased levels of IL-6 (P<0.0001), IL-10 (P<0.0001), and IL-1Ra (P<0.07) were found among patients with HUS compared with normal controls. Children with severe renal dysfunction also had tenfold increased levels of IL-6 and higher concentrations of IL-10 and IL-1Ra. Both the IL-6/IL-10 (4.9±8.3 vs. 0.5±0.4, P=0.01) and the IL-6/IL-1Ra ratios (0.10±0.20 vs. 0.01±0.01, P=0.04) were significantly increased. GFR correlated well with IL-6 levels, IL-6/IL-10 and IL-6/IL-1Ra ratios. Our data demonstrate that the inflammatory response of the host is associated with the severity of renal dysfunction during classic HUS. An imbalance between the pro-and the anti-inflammatory responses may be involved in the pathophysiology of VTEC-associated HUS.
The Pediatric Infectious Disease Journal, 1998
Recent experimental data suggest that the inflammatory response of the host to verotoxin and/or l... more Recent experimental data suggest that the inflammatory response of the host to verotoxin and/or lipopolysaccharides of Escherichia coli is involved in the pathophysiology of verotoxin-producing E. coli (VTEC) infections. We measured the circulating concentrations of cytokines [TNF-alpha, interleukin (IL)-1-beta, IL-1 receptor antagonist (Ra), IL-6, IL-8, IL-10] and soluble leukocyte adhesion molecules (L-selectin, P-selectin, E-selectin, intracellular cell adhesion molecule-1, vascular cell adhesion molecule-1) by sandwich enzyme-linked immunosorbent assay among (1) normal controls (n = 12), (2) disease controls with hemorrhagic colitis (HC) not associated with VTEC infections (n = 57), (3) patients with uncomplicated HC caused by E. coli O157:H7 (n = 30), and (4) children with hemolytic-uremic syndrome (HUS) (n = 28). Patients with HUS were matched with children who presented an uncomplicated HC caused by E. coli O157:H7 for the time interval elapsed between the onset of HC and that of blood sample collection. Concentrations of TNF-alpha and IL-1-beta were undetectable. Children with HUS were characterized by increased amounts of IL-6 and IL-8, lower values of soluble L-selectin as well as increased levels of IL-10 and IL-1Ra. The circulating concentrations of IL-1Ra were higher among children with O157:H7 HC who subsequently developed HUS. Increased pro- and antiinflammatory cytokine responses are produced by the host during the development of HUS among children with VTEC infections. Further studies are needed to determine their relative contribution to the pathophysiology of classic HUS.
The Journal of Pediatrics, 2007
To describe the presentation, management, and outcome of 43 cases of pneumococcal-associated hemo... more To describe the presentation, management, and outcome of 43 cases of pneumococcal-associated hemolytic uremic syndrome (P-HUS). An increased incidence of P-HUS has been noted in the United Kingdom between January 1998 and May 2005. Cases with microangiopathic hemolytic anemia (Hb &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;10 g/dL with fragmented RBCs), thrombocytopenia (platelet count &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 130 x 10(9)/L), acute renal impairment with oliguria and elevated plasma creatinine for age, confirmed or suspected pneumococcal infection and/or T-activation were included. The median age at presentation was 13 months (range, 5-39 months). Pneumococcus was identified in 34 of 43 cases; T-activation was identified in 36 of 37 cases. Twelve strains were serotyped: serotypes 3 (n = 2), 6A (n = 2), 12F (n = 1), 14 (n = 1), 19A (n = 6). Empyema was present in 23 of 35 pneumonia cases; 13 cases had confirmed (9) or suspected (4) pneumococcal meningitis; 36 cases required dialysis (median, 10 days; range, 2-240 days). The mortality rate was 11%, comprising 3 cases of meningitis, 1 case of sepsis and 1 case of pulmonary embolism at 8 months follow up while on dialysis. Follow-up data were available for 35 of 38 patients who survived (median follow-up period, 9 months; range, 1-63 months); of these, 10 patients had renal dysfunction, 1 patient was dialysis-dependent, 5 patients had hypertension and 8 patients had at least 1+ proteinuria on urinalysis. P-HUS has increased compared with historic surveys (0/288 in 1985-1988; 8/413 in 1997-2001, 43/315 in 1998-May 2005). Early mortality remains high (8-fold that of VTEC-induced HUS). Ten of 12 strains identified would not be covered by the PCV7 vaccine.
Critical Care Medicine, 1999
CHEST Journal, 1996
To determine the cumulated incidence and the density of incidence of systemic inflammatory respon... more To determine the cumulated incidence and the density of incidence of systemic inflammatory response syndrome (SIRS), sepsis, severe sepsis, septic shock, and multiple organ dysfunction syndrome (MODS) in critically ill children; to distinguish patients with primary from those with secondary MODS. Prospective cohort study. Pediatric ICU of a university hospital. One thousand fifty-eight consecutive hospital admissions. None. SIRS occurred in 82% (n=869) of hospital admissions, 23% (n=245) had sepsis, 4% (n=46) had severe sepsis, 2% (n=25) had septic shock; 16% (n=168) had primary MODS and 2% (n=23) had secondary MODS; 6% (n=68) of the study population died. The pediatric risk of mortality (PRISM) scores on the first day of admission to pediatric ICU were as follows: 3.9 +/- 3.6 (no SIRS), 7.0 +/- 7.0 (SIRS), 9.5 +/- 8.3 (sepsis), 8.8 +/- 7.8 (severe sepsis), 21.8 +/- 15.8 (septic shock); differences among groups (p=0.0001), all orthogonal comparisons, were significant (p&lt;0.05), except for patients with severe sepsis. The observed mortality for the whole study population was also different according to the underlying diagnostic category (p=0.0001; p&lt;0.05 for patients with SIRS and those with septic shock, compared with all groups). Among, patients with MODS, the difference in mortality between groups did not reach significance (p=0.057). Children with secondary MODS had a longer duration of organ dysfunction (p&lt;0.0001), a longer stay in pediatric ICU after MODS diagnosis (p&lt;0.0001), and a higher risk of mortality (odds ratio, 6.5 [2.7 to 15.9], p&lt;0.0001) than patients with primary MODS. SIRS and sepsis occur frequently in critically ill children. The presence of SIRS, sepsis, or septic shock is associated with a distinct risk of mortality among critically ill children admitted to the pediatric ICU; more data are needed concerning children with MODS. Secondary MODS is much less common than primary MODS, but it is associated with an increased morbidity and mortality; we speculate that distinct pathophysiologic mechanisms are involved in these two conditions.
Respiratory care, Jan 2, 2016
High-flow nasal cannula (HFNC) therapy is increasingly used in pediatric ICUs as an intermediate ... more High-flow nasal cannula (HFNC) therapy is increasingly used in pediatric ICUs as an intermediate level of support between conventional oxygen delivery and noninvasive ventilation (NIV). The safety of HFNC has seldom been studied, and some cases of barotrauma have been reported. This retrospective study aims to describe HFNC use in a tertiary care pediatric ICU, with a focus on the complications associated with this therapy. Between January 2013 and January 2014, all children <18 y old treated with HFNC in the pediatric ICU were included. Demographic data, HFNC settings, chest radiograph reports, and blood gas values were gathered from the electronic medical records. Episodes of pneumothorax, pneumomediastinum, and significant epistaxis were noted. Pneumothorax was distinguished from chest tube-related air leak (frequent after cardiac surgery), which was defined as a small pneumothorax with no clinical impact that resolved spontaneously after chest tube removal. During the 1-y stu...
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Papers by François Proulx