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University of Technology of Compiègne, France

Martin B.A.,Ecole Polytechnique Federale de Lausanne | Reymond P.,Ecole Polytechnique Federale de Lausanne | Novy J.,University of Lausanne | Baledent O.,University Hospital of Amiens | Stergiopulos N.,Ecole Polytechnique Federale de Lausanne
American Journal of Physiology - Heart and Circulatory Physiology | Year: 2012

Coupling of the cardiovascular and cerebrospinal fluid (CSF) system is considered to be important to understand the pathophysiology of cerebrovascular and craniospinal disease and intrathecal drug delivery. A coupled cardiovascular and CSF system model was designed to examine the relation of spinal cord (SC) blood flow (SCBF) and CSF pulsations along the spinal subarachnoid space (SSS). A onedimensional (1-D) cardiovascular tree model was constructed including a simplified SC arterial network. Connection between the cardiovascular and CSF system was accomplished by a transfer function based on in vivo measurements of CSF and cerebral blood flow. A 1-D tube model of the SSS was constructed based on in vivo measurements in the literature. Pressure and flow throughout the cardiovascular and CSF system were determined for different values of craniospinal compliance. SCBF results indicated that the cervical, thoracic, and lumbar SC each had a signature waveform shape. The cerebral blood flow to CSF transfer function reproduced an in vivolike CSF flow waveform. The 1-D tube model of the SSS resulted in a distribution of CSF pressure and flow and a wave speed that were similar to those in vivo. The SCBF to CSF pulse delay was found to vary a great degree along the spine depending on craniospinal compliance and vascular anatomy. The properties and anatomy of the SC arterial network and SSS were found to have an important impact on pressure and flow and perivascular fluid movement to the SC. Overall, the coupled model provides predictions about the flow and pressure environment in the SC and SSS. More detailed measurements are needed to fully validate the model. © 2012 the American Physiological Society.

Paccou J.,University Hospital of Amiens | Paccou J.,French Institute of Health and Medical Research | Fardellone P.,University Hospital of Amiens | Fardellone P.,French Institute of Health and Medical Research | And 2 more authors.
Current Opinion in Pulmonary Medicine | Year: 2013

PURPOSE OF REVIEW: This review highlights recently published data on the pathophysiology, guidelines and treatment of cystic fibrosis (CF)-related bone disease. RECENT FINDINGS: The exact role of the cystic fibrosis transmembrane conductance regulator (CFTR), specifically the ΔF508 allele, has been investigated in F508del-CFTR homozygous mice and the F508del-CFTR mutation may contribute to CF-related bone disease by slowing new bone formation. The European Cystic Fibrosis Society has issued guidelines for bone mineral density assessment, management of low-trauma fractures and bisphosphonate therapy. A systematic review based on meta-analyses reports that oral and intravenous bisphosphonates both improve bone mineral density in CF patients, but no data are available concerning the reduction of low-trauma fractures. SUMMARY: European Cystic Fibrosis Society guidelines may help physicians to improve the management of CF-related bone disease. © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins.

Repesse X.,University Hospital Ambroise Pare | Charron C.,University Hospital Ambroise Pare | Fink J.,University Hospital Ambroise Pare | Beauchet A.,University Hospital Ambroise Pare | And 6 more authors.
American Journal of Physiology - Heart and Circulatory Physiology | Year: 2015

Mean systemic filling pressure (Pmsf) is a major determinant of venous return. Its value is unknown in critically ill patients (ICU). Our objectives were to report Pmsf in critically ill patients and to look for its clinical determinants, if any. We performed a prospective study in 202 patients who died in the ICU with a central venous and/or arterial catheter. One minute after the heart stopped beating, intravascular pressures were recorded in the supine position after ventilator disconnection. Parameters at admission, during the ICU stay, and at the time of death were prospectively collected. One-minute Pmsf was 12.8 ± 5.6 mmHg. It did not differ according to gender, severity score, diagnosis at admission, fluid balance, need for and duration of mechanical ventilation, or length of stay. Nor was there any difference according to suspected cause of death, classified as shock (cardiogenic, septic, and hemorrhagic) and nonshock, although a large variability of values was observed. The presence of norepinephrine at the time of death (102 patients) was associated with a higher 1-min Pmsf (14 ± 6 vs. 11.4 ± 4.5 mmHg), whereas the decision to forgo life-sustaining therapy (34 patients) was associated with a lower 1-min Pmsf (10.9 ± 3.8 vs. 13.1 ± 5.3 mmHg). In a multiple-regression analysis, norepinephrine (β= 2.67, P = 0.0004) and age (β= –0.061, P = 0.022) were associated with 1-min Pmsf. One-minute Pmsf appeared highly variable without any difference according to the kind of shock and fluid balance, but was higher with norepinephrine. © 2015 the American Physiological Society.

Roussel M.,University Hospital of Amiens | Dujardin K.,University Hospital of Lille | Henon H.,University Hospital of Lille | Godefroy O.,University Hospital of Amiens
Brain | Year: 2012

Although frontal dysexecutive disorders are frequently considered to be due to working memory deficit, this has not been systematically examined and very little evidence is available for impairment of working memory in frontal damage. The objective of this study was to examine the components of working memory, their anatomy and the relations with executive functions in patients with stroke involving the frontal or posterior cortex. The study population consisted of 29 patients (frontal: n = 17; posterior: n = 12) and 29 matched controls. Phonological loop (letter and word spans, phonological store; rehearsal process), visuospatial sketchpad (visuospatial span) and the central executive (working memory span, dual task and updating process) were examined. The group comparison analysis showed impairment in the frontal group of: (i) verbal spans (P < 0.03); (ii) with a deficit of the rehearsal process (P = 0.006); (iii) visuospatial span (P = 0.04); (iv) working memory span (P = 0.001) that disappeared after controlling for verbal span and (v) running memory (P = 0.05) unrelated to updating conditions. The clinical anatomical correlation study showed that impairment of the central executive depended on frontal and posterior lesion. Cognitive dysexecutive disorders were observed in 11/20 patients with central executive deficit and an inverse dissociation was observed in two patients. Receiver operating characteristic curve analysis indicated that cognitive dysexecutive disorders had the highest ability to discriminate frontal lesions (area under curve = 0.844, 95% confidence interval: 0.74-0.95; P = 0.0001; central executive impairment: area under curve = 0.732, 95% confidence interval: 0.57-0.82; P = 0.006). This study reveals that frontal lesions induce mild impairment of short-term memory associated with a deficit of the rehearsal process supporting the role of the frontal lobe in this process; the central executive depends on lesions in the frontal lobe and posterior regions accounting for its low frequency and the negative results of group studies. Finally, the frontal dysexecutive syndrome cannot be attributed to central executive impairment, although it may contribute to some dysexecutive disorders. © The Author (2012). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved.

Godefroy O.,University Hospital of Amiens | Azouvi P.,University Hospital of Garches | Robert P.,University Hospital of Nice | Roussel M.,University Hospital of Amiens | And 2 more authors.
Annals of Neurology | Year: 2010

Objective: Disorders of executive functions are among the most frequent cognitive deficits, but they remain poorly defined and are subject to heterogeneous assessment. To address this major issue, the Groupe de Réflexion sur l'Evaluation des Fonctions Exécutives (GREFEX) group has proposed criteria for behavioral and cognitive dysexecutive syndromes and has designed a battery including a specific heteroquestionnaire and 7 cognitive tests. We investigated the frequency of behavioral and cognitive dysexecutive disorders in patients suffering from various diseases and the association of these disorders with loss of autonomy. Methods A total of 461 patients aged between 16 and 90 years with severe traumatic brain injury, stroke, mild cognitive impairment, Alzheimer disease, multiple sclerosis, and Parkinson disease were recruited into this prospective cohort study by 21 centers between September 2003 and June 2006. Behavioral and cognitive dysexecutive disorders were examined using the GREFEX battery. Results A dysexecutive syndrome was observed in 60% of patients, concerning both behavioral and cognitive domains in 26% and dissociated in 34%. All behavioral and cognitive dysexecutive disorders discriminated (p = 0.001, all) patients from controls. The pattern of cognitive syndrome differed (p = 0.0001) according to the disease. Finally, behavioral (odds ratio [OR], 4.6; 95% confidence interval [CI], 2. 3-9.1; p = 0.0001) and cognitive (OR, 3.36; 95% CI, 1.7-6.6; p = 0.001) dysexecutive syndromes and Mini Mental State Examination score (OR, 0.79; 95% CI, 0.68-0.91; p = 0.002) were independent predictors of loss of autonomy. Interpretation This study provided criteria of dysexecutive syndrome and showed that both behavioral and cognitive syndromes contribute to loss of autonomy. Profiles vary across patients and diseases, and therefore systematic assessment of behavioral and cognitive disorders in reference to diagnostic criteria is needed. Copyright © 2010 American Neurological Association.

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