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Chantuma P, Lacointe A, Kasemsap P, Thanisawanyangkura S, Gohet E, Clément A, Guilliot A, Améglio T, Thaler P. Carbohydrate storage in wood and bark of rubber trees submitted to different level of C demand induced by latex tapping. TREE PHYSIOLOGY 2009; 29:1021-1031. [PMID: 19556234 DOI: 10.1093/treephys/tpp043] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
When the current level of carbohydrates produced by photosynthesis is not enough to meet the C demand for maintenance, growth or metabolism, trees use stored carbohydrates. In rubber trees (Hevea brasiliensis Muell. Arg.), however, a previous study (Silpi U., A. Lacointe, P. Kasemsap, S. Thanisawanyangkura, P. Chantuma, E. Gohet, N. Musigamart, A. Clement, T. Améglio and P. Thaler. 2007. Carbohydrate reserves as a competing sink: evidence from tapping the rubber tree. Tree Physiol. 27:881-889) showed that the additional sink created by latex tapping results not in a decrease, but in an increase in the non-structural carbohydrate (NSC) storage in trunk wood. In this study, the response of NSC storage to latex tapping was further investigated to better understand the trade-off between latex regeneration, biomass and storage. Three tapping systems were compared to the untapped Control for 2 years. Soluble sugars and starch were analyzed in bark and wood on both sides of the trunk, from 50 to 200 cm from the ground. The results confirmed over the 2 years that tapped trees stored more NSC, mainly starch, than untapped Control. Moreover, a double cut alternative tapping system, which produced a higher latex yield than conventional systems, led to even higher NSC concentrations. In all tapped trees, the increase in storage occurred together with a reduction in trunk radial growth. This was interpreted as a shift in carbon allocation toward the creation of reserves, at the expense of growth, to cover the increased risk induced by tapping (repeated wounding and loss of C in latex). Starch was lower in bark than in wood, whereas it was the contrary for soluble sugars. The resulting NSC was twice as low and less variable in bark than in wood. Although latex regeneration occurs in the bark, changes related to latex tapping were more marked in wood than in bark. From seasonal dynamics and differences between the two sides of the trunk in response to tapping, we concluded that starch in wood behaved as the long-term reserve compartment at the whole trunk level, whereas starch in bark was a local buffer. Soluble sugars behaved like an intermediate, ready-to-use compartment in both wood and bark. Finally, the dynamics of carbohydrate reserves appears a relevant parameter to assess the long-term performance of latex tapping systems.
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Saint-Criq V, Le Rouzic P, Jacquot J, Clément A, Tabary O. Azithromycin is not able to decrease inflammatory process in cystic fibrosis cells. J Cyst Fibros 2008. [DOI: 10.1016/s1569-1993(08)60206-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Guillemot N, Chadelat K, Nathan N, Aubertin G, Ducou le pointe H, Clément A, Fauroux B, Epaud R. Tuméfaction sternale chez un enfant de neuf ans. Med Mal Infect 2008; 38:278-80. [DOI: 10.1016/j.medmal.2007.11.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2007] [Accepted: 11/11/2007] [Indexed: 10/22/2022]
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Ameille J, Mattei N, Laurent F, Letourneux M, Paris C, Clément A, Chamming S, Conso F, Pairon JC. Computed tomography findings in urban transportation workers with low cumulative asbestos exposure. Int J Tuberc Lung Dis 2007; 11:1352-1357. [PMID: 18034958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023] Open
Abstract
OBJECTIVE To assess the frequency of computed tomography (CT) scan pleural and interstitial changes in a population of urban transportation workers with low cumulative exposure to asbestos, and to measure inter-reader agreement. DESIGN A total of 269 male volunteers (mean age 54.0 +/- 2.3 years, mean estimated cumulative exposure index 1.7 +/- 2.3 fibres/ml-years), underwent a CT scan which was read independently by three experienced readers, with further consensus reading in case of pleural or parenchymal abnormalities. Inter-reader agreement was assessed by means of Kappa statistic. RESULTS On consensus reading, four subjects had interstitial opacities, three had diffuse pleural thickening and 26 (9.7%) had pleural plaques that were unilateral in 65% of cases and < or =2 mm thick in 54% of cases. No correlation was observed between pleural plaques and latency, duration of exposure or cumulative exposure. The inter-reader agreement for the detection of pleural abnormalities was fair. CONCLUSION In this relatively young population with low cumulative exposure to asbestos, the prevalence of pleural abnormalities was low. These abnormalities were very limited in thickness and extent, leading to marked inter-reader variability and making it difficult to assess their relationship to asbestos exposure.
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Silpi U, Lacointe A, Kasempsap P, Thanysawanyangkura S, Chantuma P, Gohet E, Musigamart N, Clément A, Améglio T, Thaler P. Carbohydrate reserves as a competing sink: evidence from tapping rubber trees. TREE PHYSIOLOGY 2007; 27:881-9. [PMID: 17331906 DOI: 10.1093/treephys/27.6.881] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Carbohydrate reserve storage in trees is usually considered a passive function, essentially buffering temporary discrepancies between carbon availability and demand in the annual cycle. Recently, however, the concept has emerged that storage might be a process that competes with other active sinks for assimilate. We tested the validity of this concept in Hevea brasiliensis Müll. Arg. (rubber) trees, a species in which carbon availability can be manipulated by tapping, which induces latex regeneration, a high carbon-cost activity. The annual dynamics of carbohydrate reserves were followed during three situations of decreasing carbon availability: control (no tapping), tapped and tapped with Ethephon stimulation. In untapped control trees, starch and sucrose were the main carbohydrate compounds. Total nonstructural carbohydrates (TNC), particularly starch, were depleted following bud break and re-foliation, resulting in an acropetal gradient of decreasing starch concentration in the stem wood. During the vegetative season, TNC concentration increased. At the end of the vegetative season, there were almost no differences in TNC concentration along the trunk. In tapped trees, the vertical gradient of starch concentration was locally disturbed by the presence of the tapping cut. However, the main effect of tapping was a dramatic increase in TNC concentration, particularly starch, throughout the trunk and in the root. The difference in TNC concentration between tapped and untapped trees was highest when latex production was highest (October); the difference was noticeable even in areas of the trees that are unlikely to be directly involved in latex regeneration, and it was enhanced by Ethephon stimulation, which is known to increase latex metabolism and flow duration. Thus, contrary to what could be expected if reserves serve as a passive buffer, a decrease in carbohydrate availability resulted in a net increase in carbohydrate reserves at the trunk scale. Such behavior supports the view that trees tend to adjust the amount of carbohydrate reserves stored to the level of metabolic demand, at the possible expense of growth.
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Duburcq X, Pouzet A, Marant L, Clément A, Duhamel D, Leirens Y, Margotteau F, Falcou-Briatte R, Bouniort F, Taskar S, Flecheux O. P1178 A comparative study of the new Access® HBs Ag assay and the HBs Ag confirmatory assay from Beckman Coulter. Int J Antimicrob Agents 2007. [DOI: 10.1016/s0924-8579(07)71018-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Nicot F, Renault F, Clément A, Fauroux B. Respiratory-related evoked potentials in children with asthma. Neurophysiol Clin 2007; 37:29-33. [PMID: 17418355 DOI: 10.1016/j.neucli.2007.01.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
AIMS OF THE STUDY Respiratory-related evoked potentials (RREPs) are a method of recording brain activities in response to respiratory stimuli. Although data in childhood are scarce, the absence of the early P1 component of RREPs has been reported in children with a history of life-threatening asthma. This study was focused on the presence, latencies, and amplitudes of the P1, N1, P2, and N2 components of the RREPs in a paediatric series of asthmatic patients. PATIENTS AND METHODS RREPs were recorded in 21 patients with stable asthma, age range 8-17 years, 11 healthy children, age range 6-16 years, and 24 healthy adults, age range 20-28 years. The signals from left (C3-Cz) and right (C4-Cz) central (rolandic) location were recorded separately, using surface electrodes. Evoked responses to two series of 80 consecutive mid-inspiratory occlusions were averaged. Recordings were analysed manually. RESULTS All 4 RREPs components were significantly more often absent in asthmatic children than in healthy children and adults (P1, p=0.01; N1, p=0.008; P2, p=0.008, N2, p=0.01). The latencies and amplitudes of the four components were similar in patients and healthy subjects. CONCLUSION RREPs components were less frequently present in children with asthma than in healthy subjects. This finding should promote the recording of RREPs in other acute and chronic respiratory diseases in children in order to search for possible electroclinical correlations.
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Fauroux B, Clément A. Requisite for stringent control of oxygen therapy in the neonatal period. Eur Respir J 2007; 29:4-5. [PMID: 17197478 DOI: 10.1183/09031936.00132306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
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Epaud R, Guillemot N, Renolleau S, Clément A, Fauroux B. 389 Diagnostic étiologique et traitement de la pneumonie à Pneumocystis Jiroveci (PJ) chez le nourrisson. Rev Mal Respir 2007. [DOI: 10.1016/s0761-8425(07)72765-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Aubertin G, Guillemot N, Fauroux B, Clément A, Epaud R. 434 Évolution des pleurésies de l’enfant. Rev Mal Respir 2007. [DOI: 10.1016/s0761-8425(07)72810-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Tabary O, Corvol H, Boncoeur E, Chadelat K, Fitting C, Cavaillon J, Clément A, Jacquot J. Neutrophil-epithelial cell crosstalk causes an amplified inflammatory response in airways of patients with cystic fibrosis. Rev Mal Respir 2006. [DOI: 10.1016/s0761-8425(06)71936-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Clément A, Droit-Volet S. Counting in a time discrimination task in children and adults. Behav Processes 2006; 71:164-71. [PMID: 16434150 DOI: 10.1016/j.beproc.2005.08.007] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2004] [Revised: 07/05/2005] [Accepted: 08/29/2005] [Indexed: 11/25/2022]
Abstract
The present study investigated in 5- and 8-year-olds, as well as in adults, the effect of verbal counting on temporal discrimination behavior in a generalization task with two duration ranges in order to test the scalar timing property. The results showed that counting improved temporal sensitivity in all age groups, although sensitivity to time remained lower in the younger children. Furthermore, in the 5-year-olds, the temporal generalization behavior conformed well to the scalar property of variance both in the counting and the non-counting condition. However, this conformity to the scalar timing property disappeared when counting was used in the 8-year-olds and the adults. The development of the ability to count time at a constant rhythm is discussed as the major reason for this departure of temporal behavior from the scalar property of variance when counting is employed.
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Brouard J, Corvol H, Boelle P, Knauer N, Vallet C, Henrion-Caude A, Boule M, Fauroux B, Ratjen F, Grasemann H, Clément A. 19 Influence of tumor necrosis factor gene polymorphisms on lung disease progression in children with Cystic Fibrosis. J Cyst Fibros 2006. [DOI: 10.1016/s1569-1993(06)80020-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Moore A, Escudier E, Roger G, Tamalet A, Pelosse B, Marlin S, Clément A, Geremek M, Delaisi B, Bridoux AM, Coste A, Witt M, Duriez B, Amselem S. RPGR is mutated in patients with a complex X linked phenotype combining primary ciliary dyskinesia and retinitis pigmentosa. J Med Genet 2005; 43:326-33. [PMID: 16055928 PMCID: PMC2563225 DOI: 10.1136/jmg.2005.034868] [Citation(s) in RCA: 180] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
INTRODUCTION Primary ciliary dyskinesia (PCD) is a rare disease classically transmitted as an autosomal recessive trait and characterised by recurrent airway infections due to abnormal ciliary structure and function. To date, only two autosomal genes, DNAI1 and DNAH5 encoding axonemal dynein chains, have been shown to cause PCD with defective outer dynein arms. Here, we investigated one non-consanguineous family in which a woman with retinitis pigmentosa (RP) gave birth to two boys with a complex phenotype combining PCD, discovered in early childhood and characterised by partial dynein arm defects, and RP that occurred secondarily. The family history prompted us to search for an X linked gene that could account for both conditions. RESULTS We found perfect segregation of the disease phenotype with RP3 associated markers (Xp21.1). Analysis of the retinitis pigmentosa GTPase regulator gene (RPGR) located at this locus revealed a mutation (631_IVS6+9del) in the two boys and their mother. As shown by study of RPGR transcripts expressed in nasal epithelial cells, this intragenic deletion, which leads to activation of a cryptic donor splice site, predicts a severely truncated protein. CONCLUSION These data provide the first clear demonstration of X linked transmission of PCD. This unusual mode of inheritance of PCD in patients with particular phenotypic features (that is, partial dynein arm defects and association with RP), which should modify the current management of families affected by PCD or RP, unveils the importance of RPGR in the proper development of both respiratory ciliary structures and connecting cilia of photoreceptors.
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Droit-Volet S, Provasi J, Delgado M, Clément A. Le développement des capacités de jugement des durées chez l'enfant. PSYCHOLOGIE FRANCAISE 2005. [DOI: 10.1016/j.psfr.2004.10.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Fauroux B, Nicot F, Essouri S, Hart N, Clément A, Polkey MI, Lofaso F. Setting of noninvasive pressure support in young patients with cystic fibrosis. Eur Respir J 2004; 24:624-30. [PMID: 15459142 DOI: 10.1183/09031936.04.0000137603] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The aim of the current study was to compare a clinical noninvasive method of setting up noninvasive pressure support ventilation (PS-NI) in young patients with cystic fibrosis (CF), based on parameters such as breathing frequency, arterial oxygen saturation and comfort rating, with a more invasive method (PS-I) targeted at optimising unloading of the inspiratory muscles and enhancing patient-ventilator synchronisation. PS-NI and PS-I were compared in random order in 10 children with CF. PS-NI differed from PS-I with regard to the level of inspiratory pressure (n=5), rate of inspiratory pressurisation (n=1), inspiratory trigger sensitivity (n=2) and expiratory trigger sensitivity (n=5). Although both methods modified breathing pattern, improved oxygen saturation and reduced diaphragmatic pressure time product (450+/-91 cmH2O.s(-1).min(-1) during spontaneous breathing, and 129+/-125 and 104+/-75 cmH2O.s(-1).min(-1) during PS-NI and PS-I, respectively), patient-ventilator synchrony and patient comfort were enhanced more during PS-I. In young patients with cystic fibrosis, setting up pressure support using a clinical noninvasive approach based on easily measurable parameters, such as respiratory rate and comfort rating, is as effective as a more invasive technique based on unloading of the inspiratory muscles and optimising patient-ventilator synchronisation. However, whilst the standard clinical method is satisfactory in the majority of patients, more invasive measurements should be considered in patients who have difficulty synchronising with the ventilator to enhance patient tolerance and compliance.
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Sapin C, Antoniotti S, Simeoni MC, Clément A, El Khammar M, Auquier P. Shortening the VSP-A: Preliminary development of the VSP-A12, a 12-item short-form. Qual Life Res 2004; 13:235-41. [PMID: 15058803 DOI: 10.1023/b:qure.0000015294.56063.7d] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The 'Vécu et Santé Perçue des Adolescents' (VSP-A) questionnaire is a French generic self-administered health-related quality of life (HRQL) instrument for adolescents which comprises 40 items, allowing the calculation of six dimensions as well as an index. Regression methods were used to select 12 items from the VSP-A to reproduce its HRQL index. The resulting 12-item short-form (VSP-A12) achieved an adjusted R2 of 0.907 in prediction of the VSP-A index. Scoring algorithm used to score this 12-item index achieved a R2 of 0.901 with the VSP-A index when cross-validated in the validation sample (n = 2941). Numerous tests of empirical validity previously published for the VSP-A were replicated for the VSP-A12, including comparisons between groups known to differ in terms of gender, age or health status. All the significant results shown by the VSP-A index were also encountered by the VSP-A12 summary measure. The ability of VSP-A12 to discriminate between healthy and ill adolescents was also proven. A test-retest correlation (4 weeks) of 0.745 was observed for the 12-item HRQL index in the target population (n = 664). Average score for this shorter index closely mirrored VSP-A index, although standard deviation was always greater for the VSP-A12.
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Clément A, Henrion-Caude A. [Alveolar epithelium repair: a clinically relevant challenge for respiratory medicine]. Rev Mal Respir 2003; 20:844-6. [PMID: 14743084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/28/2023]
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Clément A, Vigouroux B. Unsupervised segmentation of scenes containing vegetation (Forsythia) and soil by hierarchical analysis of bi-dimensional histograms. Pattern Recognit Lett 2003. [DOI: 10.1016/s0167-8655(03)00034-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Clément A, Epaud R, Tamalet A, Fauroux B. [Management of patients with cystic fibrosis: role of corticosteroid therapy]. Rev Mal Respir 2003; 20:S137-9. [PMID: 12910146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/04/2023]
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Epaud R, Fauroux B, Boule M, Clément A. [Diseases of the pulmonary lymphatic system in children]. REVUE DE PNEUMOLOGIE CLINIQUE 2003; 59:7-15. [PMID: 12717321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Diseases of the lymphatic system in children include a group of exceptional conditions difficult to manage. The anatomy of lymphatic system is complex in the lung. Variable from one subject to another, its complex physiology plays an important role in air-blood exchanges occurring in the lung. In the pulmonary interstitium and in the pleura, the lymphatic system acts like an overflow valve capable of regulating variations in interstitial fluid. The presence or development of dysplasic lymphatics causes leakage, dilatation, and reflux of the lymph through incontinent valves leading to chylothorax and/or fluid overload in the pulmonary interstitium. Symptomatic care is usually proposed, based on a fat-free diet supplemented with light-chain triglycerides and liposoluble vitamins. Other therapeutic options can be proposed. Medical options include cytotoxic agents, somatostatin, and interferon-alpha. Surgery may also be useful, but an assessment of therapeutic efficacy is very difficult due to partial effects and the small number of cases studied.
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Pin I, Brémont F, Clément A, Sardet A. [Management of pulmonary involvement in mucoviscidosis in the child]. Arch Pediatr 2001; 8 Suppl 5:856s-883s. [PMID: 11811054 DOI: 10.1016/s0929-693x(01)80006-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Fauroux B, Pigeot J, Polkey MI, Roger G, Boulé M, Clément A, Lofaso F. Chronic stridor caused by laryngomalacia in children: work of breathing and effects of noninvasive ventilatory assistance. Am J Respir Crit Care Med 2001; 164:1874-8. [PMID: 11734439 DOI: 10.1164/ajrccm.164.10.2012141] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Breathing pattern, gas exchange, and respiratory effort were assessed in five awake children with chronic stridor caused by laryngomalacia during spontaneous breathing (SB) and noninvasive mechanical ventilation (NIMV). During SB, the youngest children were able to maintain normal gas exchange at the expense of an increased work of breathing as assessed by calculated diaphragmatic pressure-time product (PTPdi), whereas the opposite was observed in the older children. NIMV increased tidal volume, from 8.77 +/- 2.04 ml/kg during SB to 11.67 +/- 2.52 ml/kg during NIMV, p = 0.04, and decreased respiratory rate, from 24.4 +/- 5.6 breaths/ min during SB to 16.6 +/- 0.9 breaths/min during NIMV, p = 0.04. NIMV unloaded the respiratory muscles as reflected by the significant reduction in PTPdi, from a mean value of 541.0 +/- 196.6 cm H(2)O x s x min(-1) during SB to 214.8 +/- 116.0 cm H(2)O x s x min(-1) during NIMV, p = 0.04. Therefore, NIMV successfully relieves the additional load imposed on the respiratory muscles. Long-term home NIMV was provided to a total of 12 children with laryngomalacia (including these five) and was associated with clinical improvement in sleep and growth.
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Droit-Volet S, Clément A, Wearden J. Temporal generalization in 3- to 8-year-old children. J Exp Child Psychol 2001; 80:271-88. [PMID: 11583526 DOI: 10.1006/jecp.2001.2629] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Children aged 3, 5, and 8 years were tested on temporal generalization with visual stimuli. Different groups received 4- and 8-s standards. Gradients at all ages superimposed when plotted on the same relative scale, indicating underlying scalar timing. The principal developmental changes were (i) increasing sharpness of the generalization gradient with increasing age and (ii) a change from symmetrical (3 and 5 years) to adultlike asymmetrical generalization gradients in the oldest children. Theoretical modeling attributed these changes to increasing precision of the reference memory of the standard with increasing age, as well as a decreased tendency to "misremember" the standard as being shorter than it actually was, as the children developed.
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Fauroux B, Pigeot J, Polkey MI, Isabey D, Clément A, Lofaso F. In vivo physiologic comparison of two ventilators used for domiciliary ventilation in children with cystic fibrosis. Crit Care Med 2001; 29:2097-105. [PMID: 11700403 DOI: 10.1097/00003246-200111000-00009] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Home noninvasive mechanical ventilation (NIMV) is used with increasing frequency for the treatment of patients with respiratory failure caused by cystic fibrosis, yet the optimal mode of ventilation in such children is unknown. We compared the physiologic short-term effects of two ventilators with different modes (one pressure support and the other assist control/volume-targeted [AC/VT]) commonly used for domiciliary ventilation. DESIGN Prospective, randomized, crossover comparison of two ventilators with different modes. SETTING Tertiary pediatric university hospital. PATIENTS Eight children with cystic fibrosis (age, 11-17 yrs) and chronic respiratory failure (pH 7.4 +/- 0.0; PaO2, 57.5 +/- 7.5 torr; PaCO2, 46.1 +/- 2.5 torr), naive to NIMV. INTERVENTIONS Two 20-min runs of pressure support and AC/VT ventilation were performed in random order, each run being preceded and followed by 20 mins of spontaneous breathing. MEASUREMENTS Flow and airway pressure and esophageal and gastric pressures were measured to calculate esophageal (PTPes) and diaphragmatic pressure-time product (PTPdi) and the work of breathing. RESULTS The two NIMV sessions significantly improved blood gas variables and increased tidal volume with no change in respiratory rate. Indexes of respiratory effort decreased significantly during the two modes of NIMV compared with spontaneous breathing, with PTPdi/min decreasing from 497.8 +/- 115.4 cm H2O x sec x min(-1) during spontaneous breathing to 127.8 +/- 98.3 cm H2O x sec x min(-1) and 184.3 +/- 79.8 cm H2O x sec x min(-1), during AC/VT and pressure support, respectively (p <.0001), and the work of breathing decreasing from 1.83 +/- 0.12 J.L-1 during spontaneous breathing to 0.48 +/- 0.32 J.L-1 and 0.75 +/- 0.30 J.L-1, during AC/VT and pressure support, respectively (p <.0001). In addition, the effect of AC/VT ventilation was significantly superior to pressure support judged by PTPes and the work of breathing, but this result was explained by three patients who adapted extremely well to the AC/VT ventilation, with the disappearance of ventilator triggering, in effect adopting a controlled mode. There was a correlation between the improvement in PTPdi/min or the work of breathing and patient's subjective impression of comfort during the AC/VT ventilation. CONCLUSIONS In awake, stable children with cystic fibrosis, both AC/VT and pressure support unloaded the respiratory muscles. The disappearance of ventilator triggering occurred in a subgroup of patients during AC/VT ventilation, and this explained the good tolerance and the superiority of this mode in the present study.
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