Aerobic physical capacity and health-related quality of life in children with sickle cell disease.

BACKGROUND: Aerobic fitness is a predictor of cardiovascular health which correlates with health-related quality of life in the general population. The aim is to evaluate the aerobic capacity by cardiopulmonary exercise test (CPET) in children with sickle cell disease in comparison with healthy matched controls. METHODS: Controlled cross-sectional study. RESULTS: A total of 72 children (24 with sickle cell disease and 48 healthy controls), aged 6-17 years old were enrolled. Children with sickle cell disease had a poor aerobic capacity, with median VO2max Z-score values significantly lower than matched controls (-3.55[-4.68; -2.02] vs. 0.25[-0.22; 0.66], P < 0.01, respectively), and a high proportion of 92% children affected by an impaired aerobic capacity (VO2max Z-score < -1.64). The VO2max decrease was associated with the level of anemia, the existence of a homozygote HbS/S mutation, restrictive lung disease and health-related quality of life. CONCLUSION: Aerobic capacity is poor in children with sickle cell disease. VO2max decrease is associated with the level of anemia, the existence of a homozygote HbS/S mutation, lung function, and health-related quality of life. These results represent a signal in favor of early initiation of cardiac rehabilitation in patients with sickle cell disease. CLINICAL TRIALS: NCT05995743. IMPACT: Aerobic fitness is a predictor of cardiovascular health which correlates with health-related quality of life in the general population. Aerobic capacity (VO2max) is poor in children with sickle cell disease, despite the absence of any pattern of heart failure. VO2max decrease was associated with the level of anemia, the existence of a homozygote HbS/S mutation, restrictive lung disease, and health-related quality of life. These results are in favor of early initiation of cardiac rehabilitation in children with sickle cell disease.

Late Ventilator-Induced Diaphragmatic Dysfunction After Extubation.

OBJECTIVES: Mechanical ventilation is associated with primary diaphragmatic dysfunction, also termed ventilator-induced diaphragmatic dysfunction. Studies evaluating diaphragmatic function recovery after extubation are lacking. We evaluated early and late recoveries from ventilator-induced diaphragmatic dysfunction in a mouse model. DESIGN: Experimental randomized study. SETTING: Research laboratory. SUBJECTS: C57/BL6 mice. INTERVENTIONS: Six groups of C57/BL6 mice. Mice were ventilated for 6 hours and then euthanatized immediately (n = 18), or 1 (n = 18) or 10 days after extubation with (n = 5) and without S107 (n = 16) treatment. Mice euthanatized immediately after 6 hours of anesthesia (n = 15) or after 6 hours of anesthesia and 10 days of recovery (n = 5) served as controls. MEASUREMENTS AND MAIN RESULTS: For each group, diaphragm force production, posttranslational modification of ryanodine receptor, oxidative stress, proteolysis, and cross-sectional areas were evaluated. After 6 hours of mechanical ventilation, diaphragm force production was decreased by 25-30%, restored to the control levels 1 day after extubation, and secondarily decreased by 20% 10 days after extubation compared with controls. Ryanodine receptor was protein kinase A-hyperphosphorylated, S-nitrosylated, oxidized, and depleted of its stabilizing subunit calstabin-1 6 hours after the onset of the mechanical ventilation, 1 and 10 days after extubation. Post extubation treatment with S107, a Rycal drug that stabilizes the ryanodine complex, did reverse the loss of diaphragmatic force associated with mechanical ventilation. Total protein oxidation was restored to the control levels 1 day after extubation. Markers of proteolysis including calpain 1 and calpain 2 remained activated 10 days after extubation without significant changes in cross-sectional areas. CONCLUSIONS: We report that mechanical ventilation is associated with a late diaphragmatic dysfunction related to a structural alteration of the ryanodine complex that is reversed with the S107 treatment.

Use of Treprostinil in Pediatric Pulmonary Hypertension: Case Reports and Review of the Literature.

BACKGROUND: Add-on therapy with prostacyclin in pediatric refractory pulmonary hypertension (PH) poses a challenge, especially when considering continuous intravenous administration in younger children. A search for alternate routes of drug delivery has led to the clinical investigation of stable and long-acting prostacyclin analogues, such as subcutaneous treprostinil. We reported 2 pediatric cases of PH treated with subcutaneous treprostinil and reviewed the literature on treprostinil use in children. METHOD: The literature review used 3 electronic databases and a combination of terms (treprostinil, pediatric, PH, prostanoid, etc). We also searched for pediatric clinical trials on treprostinil registered on international clinical trial registries. RESULTS: The reported cases highlighted the multifactorial nature of PH in pediatrics: a female child with a giant omphalocele, and intracardiac and extracardiac shunts; and a male premature child with a congenital diaphragmatic hernia and long-term PH. The literature review identified 19 studies reporting treprostinil use in 421 children with various types of PH (groups 1 and 3). Subcutaneous treprostinil was the most administered formulation, at a mean dose of 40 ng/kg/min. Overall, 12 clinical trials on treprostinil for children with PH were registered on the clinical trial registries. Most authors concluded that subcutaneous treprostinil was effective, well tolerated, and represented an alternative to intravenous epoprostenol. CONCLUSIONS: Subcutaneous treprostinil may be a useful adjunct in the therapeutic algorithm for children with severe PH, refractory to oral drugs, and after a complete check-up for all PH etiologies.

Obstructive sleep apnea syndrome after hematopoietic stem cell transplantation in children with mucopolysaccharidosis type I.

BACKGROUND: Obstructive sleep apnea syndrome (OSAS) is very common in mucopolysaccharidosis I (MPS I). Hematopoietic stem cell transplantation (HSCT) is the preferred treatment for patients with severe MPS I diagnosed early in life. The protective effect of HSCT on the development of long term OSAS is not known. METHODS: Overnight polysomnography (PSG) and biomarker data were analyzed during the annual follow-up in consecutive MPS I patients treated with HSCT. RESULTS: The data of 13 patients (6 boys) were analyzed. Median age at HSCT was 17 (range 14-19) months, median age at PSG was 9.0 (4.5-14.5) years, and median time elapsed since HSCT was 7.6 (2.4-13.2) years. A significant correlation was observed between time elapsed since HSCT and the apnea-hypopnea index (AHI, r(2)=0.493, p=+0.003) and the oxygen desaturation index (r(2)=0.424, p=+0.02). Patients older than 10 years of age had a higher mean AHI (25.8/h vs 1.4/h, p=0.0008), a lower mean pulse oximetry (94.7% vs 97.2%, p=0.01) and a higher mean hypopnea index (18.8 vs 0.71/h, p=0.016) as compared to those younger than 10 years of age. No correlation was observed between the AHI and the metabolic clearance, assessed by urine glycosaminoglycan (GAG) excretion and residual enzyme activity, although there was a positive trend for the urinary GAG/higher normal value for age ratio (p=0.09). CONCLUSION: HSCT does not offer long term protection against OSAS in MPS I with OSAS being documented in all patients after a time elapse since HSCT exceeding 10 years. The potential benefit of additional enzyme replacement therapy needs to be assessed.

Non-invasive respiratory support in children and young adults with complex medical conditions in pediatric palliative care.

OBJECTIVE: Dyspnoea and sleep-disordered breathing (SDB) are common in children with life-limiting conditions but studies on treatment with non-invasive ventilation (NIV) or continuous positive airway pressure (CPAP) are scarce. The aim of the study was to describe children treated with long-term NIV/CPAP within a paediatric palliative care programme in France. METHODS: Cross-sectional survey on children and young adults with complex medical conditions treated within the French paediatric NIV network with long-term NIV/CPAP. Characteristics of the patients were analysed and patient-related outcome measures of NIV/CPAP benefit were reported. RESULTS: The data of 50 patients (68% boys), median age 12 (0.4-21) years were analysed. Twenty-three (46%) patients had a disorder of the central nervous system and 5 (10%) a chromosomal anomaly. Thirty-two (64%) patients were treated with NIV and 18 (36%) with CPAP. NIV/CPAP was initiated on an abnormal Apnoea-Hypopnoea Index in 18 (36%) of the patients, an abnormal nocturnal gas exchange alone in 28 (56%), and after an acute respiratory failure in 11 (22%) of the patients. Mean objective NIV/CPAP adherence was 9.3±3.7 hours/night. NIV/CPAP was associated with a decrease in dyspnoea in 60% of patients, an increase in sleep duration in 60% and in sleep quality in 74%, and an improvement in parents' sleep in 40%. CONCLUSIONS: In children with life-limiting conditions, long-term NIV/CPAP may be associated with relief of dyspnoea, an improvement of SDB and an improvement in parents' sleep.

Lung volume recruitment and airway clearance for children at home in France.

BACKGROUND: Airway clearance (ACT) and lung volume recruitment (LVR) techniques are used to manage bronchial secretions, increase cough efficiency and lung/chest wall recruitment, to prevent and treat respiratory tract infections. The aim of the study was to review the prescription of ACT/LVR techniques for home use in children in France. METHODS: All the centers of the national pediatric noninvasive ventilation (NIV) network were invited to fill in an anonymous questionnaire for every child aged ≤20 years who started a treatment with an ACT/LVR device between 2022 and 2023. The devices comprised mechanical in-exsufflation (MI-E), intermittent positive pressure breathing (IPPB), intrapulmonary percussive ventilation (IPV), and/or invasive mechanical ventilation (IMV)/NIV for ACT/LVR. RESULTS: One hundred and thirty-nine patients were included by 13 centers. IPPB was started in 83 (60 %) patients, MI-E in 43 (31 %) and IPV in 30 (22 %). No patient used IMV/NIV for ACT/LVR. The devices were prescribed mainly by pediatric pulmonologists (103, 74 %). Mean age at initiation was 8.9 ± 5.6 (0.4-18.5) years old. The ACT/LVR devices were prescribed mainly in patients with neuromuscular disorders (n = 66, 47 %) and neurodisability (n = 37, 27 %). The main initiation criteria were cough assistance (81 %) and airway clearance (60 %) for MI-E, thoracic mobilization (63 %) and vital capacity (47 %) for IPPB, and airway clearance (73 %) and repeated respiratory exacerbations (57 %) for IPV. The parents were the main carers performing the treatment at home. CONCLUSIONS: IPPB was the most prescribed technique. Diseases and initiation criteria are heterogeneous, underlining the need for studies validating the indications and settings of these techniques.

Pediatric long-term noninvasive respiratory support in children with central nervous system disorders.

RATIONALE: The use of long-term noninvasive respiratory support is increasing in children along with an extension of indications, in particular in children with central nervous system (CNS) disorders. OBJECTIVE: The aim of this study was to describe the characteristics of children with CNS disorders treated with long-term noninvasive respiratory support in France. METHODS: Data were collected from 27 French pediatric university centers through an anonymous questionnaire filled for every child treated with noninvasive ventilatory support ≥3 months on 1st June 2019. MAIN RESULTS: The data of 182 patients (55% boys, median age: 10.2 [5.4;14.8] years old [range: 0.3-25]) were collected: 35 (19%) patients had nontumoral spinal cord injury, 22 (12%) CNS tumors, 63 (35%) multiple disabilities, 26 (14%) central alveolar hypoventilation and 36 (20%) other CNS disorders. Seventy five percent of the patients were treated with noninvasive ventilation (NIV) and 25% with continuous positive airway pressure (CPAP). The main investigations performed before CPAP/NIV initiation were nocturnal gas exchange recordings, alone or coupled with poly(somno)graphy (in 29% and 34% of the patients, respectively). CPAP/NIV was started in an acute setting in 10% of the patients. Median adherence was 8 [6;10] hours/night, with 12% of patients using treatment <4 h/day. Nasal mask was the most common interface (70%). Airway clearance techniques were used by 31% of patients. CONCLUSION: CPAP/NIV may be a therapeutic option in children with CNS disorders. Future studies should assess treatment efficacy and patient reported outcome measures.

Cardiopulmonary fitness in children with asthma versus healthy children.

OBJECTIVES: To evaluate, with a cardiopulmonary exercise test (CPET), the cardiopulmonary fitness of children with asthma, in comparison to healthy controls, and to identify the clinical and CPET parameters associated with the maximum oxygen uptake (VO2max) in childhood asthma. DESIGN: This cross-sectional controlled study was carried out in CPET laboratories from two tertiary care paediatric centres. The predictors of VO2max were determined using a multivariable analysis. RESULTS: A total of 446 children (144 in the asthma group and 302 healthy subjects) underwent a complete CPET. Mean VO2max was significantly lower in children with asthma than in controls (38.6±8.6 vs 43.5±7.5 mL/kg/min; absolute difference (abs. diff.) of -4.9 mL/kg/min; 95% CI of (-6.5 to -3.3) mL/kg/min; p<0.01) and represented 94%±9% and 107%±17% of predicted values, respectively (abs. diff. -13%; 95% CI (-17 to -9)%; p<0.01). The proportion of children with an impaired VO2max was four times higher in the asthma group (24% vs 6%, p<0.01). Impaired ventilatory efficiency with increased VE/VCO2 slope and low breathing reserve (BR) were more marked in the asthma group. The proportion of children with a decreased ventilatory anaerobic threshold (VAT), indicative of physical deconditioning, was three times higher in the asthma group (31% vs 11%, p<0.01). Impaired VO2max was associated with female gender, high body mass index (BMI), FEV1, low VAT and high BR. CONCLUSION: Cardiopulmonary fitness in children with asthma was moderately but significantly altered compared with healthy children. A decreased VO2max was associated with female gender, high BMI and the pulmonary function. TRIAL REGISTRATION NUMBER: NCT04650464.

Reference values of aerobic fitness in the contemporary paediatric population.

AIMS: There has been a growing interest in the use of markers of aerobic physical fitness (VO2max assessed by cardiopulmonary exercise test (CPET)) in the follow-up of paediatric chronic diseases. The dissemination of CPET in paediatrics requires valid paediatric VO2max reference values to define the upper and lower normal limits. This study aimed to establish VO2max reference Z-score values, from a large cohort of children representative of the contemporary paediatric population, including those with extreme weights. METHODS AND RESULTS: In this cross-sectional study, 909 children aged 5 to 18 years old from the general French population (development cohort) and 232 children from the general German and US populations (validation cohort) underwent a CPET, following the guidelines on high-quality CPET assessment. Linear, quadratic, and polynomial mathematical regression equations were applied to identify the best VO2max Z-score model. Predicted and observed VO2max values using the VO2max Z-score model, and the existing linear equations were compared, in both development and validation cohorts. For both sexes, the mathematical model using natural logarithms of VO2max, height, and BMI was the best fit for the data. This Z-score model could be applied to normal and extreme weights and was more reliable than the existing linear equations, in both internal and external validity analyses (https://play.google.com/store/apps/details?id=com.d2l.zscore). CONCLUSION: This study established reference Z-score values for paediatric cycloergometer VO2max using a logarithmic function of VO2max, height, and BMI, applicable to normal and extreme weights. Providing Z-scores to assess aerobic fitness in the paediatric population should be useful in the follow-up of children with chronic diseases. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov NCT04876209.

Reference Values of Cardiopulmonary Exercise Test Parameters in the Contemporary Paediatric Population.

BACKGROUND: The evaluation of health status by cardiopulmonary exercise test (CPET) has shown increasing interest in the paediatric population. Our group recently established reference Z-score values for paediatric cycle ergometer VO2max, applicable to normal and extreme weights, from a cohort of 1141 healthy children. There are currently no validated reference values for the other CPET parameters in the paediatric population. This study aimed to establish, from the same cohort, reference Z-score values for the main paediatric cycle ergometer CPET parameters, apart from VO2max. RESULTS: In this cross-sectional study, 909 healthy children aged 5-18 years old underwent a CPET. Linear, quadratic, and polynomial mathematical regression equations were applied to identify the best CPET parameters Z-scores, according to anthropometric parameters (sex, age, height, weight, and BMI). This study provided Z-scores for maximal CPET parameters (heart rate, respiratory exchange ratio, workload, and oxygen pulse), submaximal CPET parameters (ventilatory anaerobic threshold, VE/VCO2 slope, and oxygen uptake efficiency slope), and maximum ventilatory CPET parameters (tidal volume, respiratory rate, breathing reserve, and ventilatory equivalent for CO2 and O2). CONCLUSIONS: This study defined paediatric reference Z-score values for the main cycle ergometer CPET parameters, in addition to the existing reference values for VO2max, applicable to children of normal and extreme weights. Providing Z-scores for CPET parameters in the paediatric population should be useful in the follow-up of children with various chronic diseases. Thus, new paediatric research fields are opening up, such as prognostic studies and clinical trials using cardiopulmonary fitness outcomes. Trial registration NCT04876209-Registered 6 May 2021-Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT04876209 .

Amikacin Liposomal Inhalation Suspension in the Treatment of Mycobacterium abscessus Lung Infection: A French Observational Experience.

Background: Mycobacterium abscessus infections remain difficult to manage in both cystic fibrosis (CF) and non-CF patients and reported clinical outcomes are largely unsatisfactory. Clinical trial data are limited and no approved therapies are currently available for the management of M abscessus lung diseases. As an alternative, cohort studies may provide insightful information into the management of M abscessus pulmonary disease. Methods: Based on a retrospective observational cohort study, we investigated the safety and efficacy of amikacin liposome inhaled suspension (ALIS) as an adjunct to a standard antibiotic regimen for M abscessus lung infection in both CF and non-CF patients. We also assessed the association of patient drug compliance with culture conversion and clinical outcomes. Results: Twenty-six patients had long-term follow-up data available. Culture conversion was achieved in 54% (14/26) of the patients with no difference between CF and non-CF patients after an average treatment duration of 10 months. Patient treatment compliance was significantly better in the converter group compared to nonconverters with an odds ratio of 44.78 associated with good compared to poor patient compliance. Overall, 9 patients (35%) experienced an adverse event that led to treatment discontinuation. Conclusions: ALIS appears beneficial in both CF and non-CF populations with M abscessus lung disease.

Long term noninvasive ventilation and continuous positive airway pressure in children with neuromuscular diseases in France.

The aim of the study was to describe the characteristics of children with neuromuscular diseases treated with long term noninvasive ventilation or continuous positive airway pressure in France. On June 1st 2019, 387 patients (63% boys, mean age 11.2 ± 5.5 years) were treated with long term noninvasive ventilation/continuous positive airway pressure. Thirty three percent of patients had spinal muscular atrophy, 30% congenital myopathy/dystrophy, 20% Duchenne muscular dystrophy, 7% Steinert myotonic dystrophy, and 9% other neuromuscular diseases. Ninety-four percent of patients were treated with long term noninvasive ventilation and 6% with continuous positive airway pressure. Treatment was initiated electively for 85% of patients, mainly on an abnormal overnight gas exchange recording (38% of patients). Noninvasive ventilation/continuous positive airway pressure was initiated during a respiratory exacerbation in 15% of patients. Mean duration of noninvasive ventilation/continuous positive airway pressure was 3.3 ± 3.1 years. Mean objective long term noninvasive ventilation/continuous positive airway pressure use was 8.0 ± 3.1 h/24. Spinal muscular atrophy, congenital myopathy/dystrophy, and Duchenne muscular dystrophy represented 83% of children with neuromuscular diseases treated with long term noninvasive ventilation in France. Screening for nocturnal hypoventilation was satisfactory as noninvasive ventilation /continuous positive airway pressure was predominantly initiated electively.

Paediatric long term continuous positive airway pressure and noninvasive ventilation in France: A cross-sectional study.

OBJECTIVE: To describe the characteristics of children treated with long term continuous positive airway pressure (CPAP) or noninvasive ventilation (NIV) in France. DESIGN: Cross-sectional national survey. SETTING: Paediatric CPAP/NIV teams of 28 tertiary university hospitals in France. PATIENTS: Children aged <20 years treated with CPAP/NIV since at least 3 months on June 1st, 2019. INTERVENTION: An anonymous questionnaire was filled in for every patient. RESULTS: The data of 1447 patients (60% boys), mean age 9.8 ± 5.8 years were analysed. The most frequent underlying disorders were: upper airway obstruction (46%), neuromuscular disease (28%), disorder of the central nervous system (13%), cardiorespiratory disorder (7%), and congenital bone disease (4%). Forty-five percent of the patients were treated with CPAP and 55% with NIV. Treatment was initiated electively for 92% of children, while 8% started during an acute illness. A poly(somno)graphy (P(S)G) was performed prior to treatment initiation in 26%, 36% had a P(S)G with transcutaneous carbon dioxide monitoring (PtcCO2), while 23% had only a pulse oximetry (SpO2) with PtcCO2 recording. The decision of CPAP/NIV initiation during an elective setting was based on the apnea-hypopnea index (AHI) in 41% of patients, SpO2 and PtcCO2 in 25% of patients, and AHI with PtcCO2 in 25% of patients. Objective adherence was excellent with a mean use of 7.6 ± 3.2 h/night. Duration of CPAP/NIV was 2.7 ± 2.9 years at the time of the survey. CONCLUSION: This survey shows the large number of children treated with long term CPAP/NIV in France with numerous children having disorders other than neuromuscular diseases.

Impact of Sophrology on cardiopulmonary fitness in teenagers and young adults with a congenital heart disease: The SOPHROCARE study rationale, design and methods.

BACKGROUND: Recent advances in the field of congenital heart disease (CHD) have significantly improved the overall prognosis. Now more attention is being given to health-related quality of life (HRQoL) and promotion of physical activity. Non-invasive relaxation therapy may be effective in cardiac patients concerned with exercise-induced dyspnoea. The SOPHROCARE randomised trial aims to assess the impact of Caycedian Sophrology on cardiopulmonary fitness in adolescents and young adults with CHD. METHODS: The SOPHROCARE trial is a nationwide, multicentre, randomised, controlled study in CHD patients aged from 13 to 25 years old. Patients will be randomised into 2 groups (8 Sophrology group sessions vs. no intervention). The primary outcome is the change in percent predicted maximum oxygen uptake (VO2max) between baseline and 12-month follow-up. A total of 94 patients in each group is required to observe a significant increase of 10% in VO2max with a power of 80% and an alpha risk of 5%. The secondary outcomes are: clinical outcomes, cardiopulmonary exercise test parameters (VE/VCO2 slope, ventilatory anaerobic threshold, oxygen pulse, respiratory response to hypercapnia), health-related quality of life score (PedsQL), physical and psychological status. CONCLUSION: After focusing on the survival in CHD, current research is opening on secondary prevention and patient-related outcomes. We sought to assess in the SOPHROCARE trial, if a Sophrology program, could improve exercise capacity and quality of life in youth with CHD. TRIAL REGISTRATION: Clinicaltrials.gov (NCT03999320).

Impaired pulmonary function and its association with clinical outcomes, exercise capacity and quality of life in children with congenital heart disease.

BACKGROUND: Impaired pulmonary function is an independent predictor of mortality in adult congenital heart disease (CHD), but has been scarcely studied in the paediatric CHD population. AIMS: To compare the pulmonary function of children with CHD to healthy controls, and evaluate its association with clinical outcomes, exercise capacity, and quality of life. METHODS: Cross-sectional multicentre study among 834 children (555 CHD and 279 control subjects) who underwent a complete spirometry and a cardiopulmonary exercise test (CPET). The 5th centile (Z-score = -1.64) was used to define the lower limit of normal. The association of clinical and CPET variables with spirometry was studied using a multivariate analysis. Children and their parents filled in the Kidscreen health-related quality of life questionnaire. RESULTS: Forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1) Z-scores values were lower in children with CHD than controls (-0.4 ±â€¯1.5 vs. 0.4 ±â€¯1.3, P < 0.001 and -0.5 ±â€¯1.4 vs. 0.4 ±â€¯1.2, P < 0.001, respectively), without any obstructive airway disorder. Restrictive pattern was more frequent in CHD patients than in controls (20% vs. 4%, P < 0.0001). FVC Z-scores were predominantly impaired in complex CHD, such as heterotaxy (-1.1 ±â€¯0.6), single ventricle (-1.0 ±â€¯0.2), and complex anomalies of the ventricular outflow tracts (-0.9 ±â€¯0.1). In multivariate analysis, FVC was associated with age, body mass index, peak oxygen uptake, genetic anomalies, the number of cardiac surgery and cardiac catheter procedures. FVC and FEV1 correlated with self and proxy-related quality of life scores. CONCLUSION: These results suggest that pulmonary function should be monitored early in life, from childhood, in the CHD population. TRIAL REGISTRATION NUMBER: NCT01202916, post-results.

Effect of pyridostigmine on in vivo and in vitro respiratory muscle of mdx mice.

The current work was conducted to verify the contribution of neuromuscular transmission defects at the neuromuscular junction to Duchenne Muscular Dystrophy disease progression and respiratory dysfunction. We tested pyridostigmine and pyridostigmine encapsulated in liposomes (liposomal PYR), an acetylcholinesterase inhibitor to improve muscular contraction on respiratory muscle function in mdx mice at different ages. We evaluated in vivo with the whole-body plethysmography, the ventilatory response to hypercapnia, and measured in vitro diaphragm strength in each group. Compared to C57BL10 mice, only 17 and 22 month-old mdx presented blunted ventilatory response, under normocapnia and hypercapnia. Free pyridostigmine (1mg/kg) was toxic to mdx mice, unlike liposomal PYR, which did not show any side effect, confirming that the encapsulation in liposomes is effective in reducing the toxic effects of this drug. Treatment with liposomal PYR, either acute or chronic, did not show any beneficial effect on respiratory function of this DMD experimental model. The encapsulation in liposomes is effective to abolish toxic effects of drugs.

An interactive medical image segmentation system based on the optimal management of regions of interest using topological medical knowledge.

This paper presents an original interactive system for efficient medical image segmentation in computer aided diagnosis. The main originality concerns the method used to manage, according to an a priori topological-based structural model, regions of interest (ROIs) within which computations can be constrained. The goal is then to avoid the processing of irrelevant image points, therefore improving and accelerating segmentations. In the case of a hierarchical modeling procedure, our ROI management method enables, for delineating a given medical structure, to optimally determine image points of interest by taking previously segmented structures into account. We propose a mathematical formulation of the method as well as a possible implementation within an interactive system. We also detail an experience report focussing on the segmentation of several abdominal structures from a CT image. It illustrates the behavior and the potential of our method.

A modular and evolutive component oriented software architecture for patient modeling.

This paper deals with the design aspect of a software aiming at modeling the anatomical and pathological structures of patients from medical images, for diagnosis purposes. In terms of functionalities, it allows to combine image processing algorithms, and to visualize and manipulate 3D models and images. The proposed software uses specific extensible and reusable components and a system managing their combination, thanks to a formal XML-based description of their interfaces. This architecture facilitates the dynamic integration of new functionalities, in particular in terms of image processing algorithms. We describe the structural and behavioral aspects of the proposed reusable component-based architecture. We also discuss the potential of this work for developing other softwares in the field of computer aided surgery.