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1.
COPD ; 12(1): 62-70, 2015 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-24921977

RESUMEN

It is well-established that COPD patients have a burden of vascular disease that cannot be fully-explained by smoking history but the mechanistic links between atherosclerosis and pulmonary disease in COPD patients are not well-understood. Moreover, in ex-smokers without symptoms or other evidence of COPD, subclinical pulmonary and vascular disease, although potentially present, has not been described or evaluated. Hence our aim was to use sensitive three-dimensional (3D) pulmonary and carotid imaging to quantify pulmonary airway/parenchyma abnormalities and atherosclerosis in ex-smokers without airflow limitation or symptoms consistent with COPD. We evaluated 61 subjects without airflow limitation including 34 never- (72 ± 6 years) and 27 ex-smokers (73 ± 9 years), who provided written informed consent to spirometry, plethysmography, (3)He magnetic resonance imaging (MRI) and carotid ultrasound (US) and, for ex-smokers alone, thoracic X-ray computed tomography (CT). Ex-smokers had significantly greater (3)He ventilation defect percent (VDP = 7%, p = 0.001) and carotid total plaque volume (TPV = 250 mm(3), p = 0.002) than never-smokers, although there were no significant differences for spirometry or plethysmography, and CT airway and emphysema measurements were normal. There were univariate relationships for (3)He VDP with carotid intima media thickness (IMT, r = 0.42, p = 0.004), TPV (r = 0.41, p = 0.006) and vessel wall volume (VWV, r = 0.40, p = 0.007). Multivariate models that included age, BMI, FEV1, DLCO and VDP showed that only VDP significantly predicted IMT (ß = 0.41, p = 0.001), VWV (ß = 0.45, p = 0.003) and TPV (ß = 0.38, p = 0.005). In summary, there was imaging evidence of mild airways disease and carotid plaque burden that were related and significantly greater in ex-smokers without airflow limitation than in never-smokers.


Asunto(s)
Enfermedades de las Arterias Carótidas/etiología , Enfermedad Pulmonar Obstructiva Crónica/etiología , Cese del Hábito de Fumar , Fumar/efectos adversos , Anciano , Anciano de 80 o más Años , Enfermedades de las Arterias Carótidas/diagnóstico , Grosor Intima-Media Carotídeo , Estudios de Casos y Controles , Femenino , Humanos , Imagenología Tridimensional , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Análisis Multivariante , Pletismografía , Enfermedad Pulmonar Obstructiva Crónica/diagnóstico , Enfermedad Pulmonar Obstructiva Crónica/fisiopatología , Análisis de Regresión , Factores de Riesgo , Índice de Severidad de la Enfermedad , Espirometría , Tomografía Computarizada por Rayos X
2.
Thorax ; 69(1): 63-71, 2014 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-23956019

RESUMEN

BACKGROUND: Hyperpolarised (3)He MRI provides a way to visualise regional pulmonary functional abnormalities that in asthma are thought to be related to airway morphological abnormalities. However, the exact aetiology of ventilation defects in asthma is not well understood. OBJECTIVE: To better understand the determinants of ventilation defects in asthma, we evaluated well-established clinical as well as (3)He MRI and X-ray CT airway measurements in healthy subjects and subjects with asthma. METHODS: Thirty-four subjects (n=26 subjects with asthma, n=8 healthy volunteers) underwent MRI, spirometry, plethysmography, fraction of exhaled nitric oxide analysis, methacholine challenge and CT for a region-of-interest proximal to ventilation defects. For subjects who consented to CT (n=18 subjects with asthma, n=5 healthy volunteers), we evaluated 3(rd) to 5th generation airway wall area and wall thickness per cent and lumen area. RESULTS: Seventeen subjects with asthma (17/26=65%) had visually obvious evidence of (3)He ventilation defects prior to bronchoprovocation and nine subjects with asthma had no ventilation defects prior to bronchoprovocation (9/26=35%). Subjects with asthma with defects were older (p=0.01) with worse forced expiratory volume in 1 s (FEV1)/forced vital capacity (p=0.0003), airways resistance (p=0.004), fraction of exhaled nitric oxide (p=0.03), greater bronchoprovocation concentration of methacholine that reduced FEV1 by 20% (p=0.008) and wall thickness per cent (p=0.02) compared with subjects with asthma without defects. There was a moderate correlation for wall area per cent with ventilation defect per cent (r=0.43, p=0.04). CONCLUSIONS: Subjects with asthma with (3)He ventilation defects were older with significantly worse airway hyper-responsiveness, inflammation and airway remodelling but similar FEV1 as subjects with asthma without defects; hyperpolarised (3)He ventilation abnormalities were spatially and quantitatively related to abnormally remodelled airways.


Asunto(s)
Asma/fisiopatología , Bronquios/patología , Bronquios/fisiopatología , Ventilación Pulmonar/fisiología , Adulto , Obstrucción de las Vías Aéreas/patología , Obstrucción de las Vías Aéreas/fisiopatología , Asma/patología , Pruebas de Provocación Bronquial , Femenino , Helio , Humanos , Pulmón/fisiopatología , Imagen por Resonancia Magnética , Masculino , Cloruro de Metacolina , Persona de Mediana Edad , Pletismografía , Espirometría , Tomografía Computarizada por Rayos X , Adulto Joven
3.
Thorax ; 68(8): 752-9, 2013 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-23604381

RESUMEN

BACKGROUND: The functional effects of abnormal diffusing capacity for carbon monoxide (DLCO) in ex-smokers without chronic obstructive pulmonary disease (COPD) are not well understood. OBJECTIVE: We aimed to evaluate and compare well established clinical, physiological and emerging imaging measurements in ex-smokers with normal spirometry and abnormal DLCO with a group of ex-smokers with normal spirometry and DLCO and ex-smokers with Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage I COPD. METHODS: We enrolled 38 ex-smokers and 15 subjects with stage I COPD who underwent spirometry, plethysmography, St George's Respiratory Questionnaire (SGRQ), 6 min Walk Test (6MWT), x-ray CT and hyperpolarised helium-3 ((3)He) MRI. The 6MWT distance (6MWD), SGRQ scores, (3)He MRI apparent diffusion coefficients (ADC) and CT attenuation values below -950 HU (RA950) were evaluated. RESULTS: Of 38 ex-smokers without COPD, 19 subjects had abnormal DLCO with significantly worse ADC (p=0.01), 6MWD (p=0.008) and SGRQ (p=0.01) but not RA950 (p=0.53) compared with 19 ex-smokers with normal DLCO. Stage I COPD subjects showed significantly worse ADC (p=0.02), RA950 (p=0.0008) and 6MWD (p=0.005), but not SGRQ (p=0.59) compared with subjects with abnormal DLCO. There was a significant correlation for (3)He ADC with SGRQ (r=0.34, p=0.02) and 6MWD (r=-0.51, p=0.0002). CONCLUSIONS: In ex-smokers with normal spirometry and CT but abnormal DLCO, there were significantly worse symptoms, 6MWD and (3)He ADC compared with ex-smokers with normal DLCO, providing evidence of the impact of mild or early stage emphysema and a better understanding of abnormal DLCO and hyperpolarised (3)He MRI in ex-smokers without COPD.


Asunto(s)
Monóxido de Carbono/farmacocinética , Tolerancia al Ejercicio/fisiología , Helio , Enfermedad Pulmonar Obstructiva Crónica/diagnóstico , Fumar , Anciano , Anciano de 80 o más Años , Antimetabolitos/farmacocinética , Imagen de Difusión por Resonancia Magnética/métodos , Femenino , Estudios de Seguimiento , Volumen Espiratorio Forzado , Helio/química , Humanos , Masculino , Persona de Mediana Edad , Pletismografía , Enfermedad Pulmonar Obstructiva Crónica/metabolismo , Enfermedad Pulmonar Obstructiva Crónica/fisiopatología , Pruebas de Función Respiratoria , Encuestas y Cuestionarios , Tomografía Computarizada por Rayos X , Capacidad Vital
4.
Respirology ; 17(8): 1237-46, 2012 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-22889229

RESUMEN

BACKGROUND AND OBJECTIVE: Spirometry is insensitive to small airway abnormalities in asthma. Our objective was to evaluate regional lung structure and function using hyperpolarized (3)He magnetic resonance imaging (MRI) before, during and after a methacholine challenge (MCh). METHODS: Twenty-five asthmatics (mean age = 34 ± 11 years) and eight healthy volunteers (HV) (mean age = 33 ± 11 years) underwent spirometry, plethysmography and hyperpolarized (3)He MRI prior to a MCh. MRI was repeated following the MCh and again 25 min after salbutamol administration. (3)He MRI gas distribution was quantified using semiautomated segmentation of the ventilation defect percent (VDP). Tissue microstructure was measured using the (3)He apparent diffusion coefficient (ADC). Analysis of variance with repeated measures was used to evaluate changes at each time point as well as to determine interactions between regions of interest (ROI) and subject group. Pearson's correlations were performed to evaluate associations between (3)He MRI measurements and established clinical measures. RESULTS: In asthmatics, but not HV, whole-lung ADC was increased post-MCh (P < 0.01). In asthmatics only, ADC was increased post-MCh in posterior ROI (P < 0.01) and all ROI in the superior-inferior direction (P < 0.01). VDP was increased in posterior and inferior ROI (P < 0.001). There was a correlation between VDP and specific airway resistance (r = 0.74, P < 0.0001), dyspnoea score (r = 0.66, P < 0.01) and fractional exhaled nitric oxide (r = 0.45, P < 0.05). CONCLUSIONS: We evaluated the regional pulmonary response to methacholine and salbutamol using (3)He MRI and showed heterogeneous VDP and ADC consistent with bronchoconstriction and gas trapping, respectively, post-MCh. These regional alterations resolved post-salbutamol.


Asunto(s)
Asma/fisiopatología , Pruebas de Provocación Bronquial , Broncoconstrictores , Pulmón/efectos de los fármacos , Imagen por Resonancia Magnética/métodos , Cloruro de Metacolina , Adulto , Resistencia de las Vías Respiratorias/efectos de los fármacos , Resistencia de las Vías Respiratorias/fisiología , Albuterol/administración & dosificación , Broncoconstricción/efectos de los fármacos , Broncoconstricción/fisiología , Broncoconstrictores/administración & dosificación , Femenino , Helio/administración & dosificación , Humanos , Pulmón/irrigación sanguínea , Pulmón/fisiología , Masculino , Cloruro de Metacolina/administración & dosificación , Persona de Mediana Edad , Ventilación Pulmonar/efectos de los fármacos , Ventilación Pulmonar/fisiología , Pruebas de Función Respiratoria , Adulto Joven
5.
Thorax ; 66(8): 680-5, 2011 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-21680566

RESUMEN

BACKGROUND: Despite advances in treatment of cystic fibrosis (CF), pulmonary exacerbations remain common. The aim of this study was to determine if frequent pulmonary exacerbations are associated with greater declines in lung function, or an accelerated time to death or lung transplantation in adults with CF. METHODS: A 3-year prospective cohort study was conducted on 446 adult patients with CF from Ontario, Canada who could spontaneously produce sputum. Patients enrolled from 2005 to 2008 and were stratified into groups based upon their exacerbation rates over the 3 year study: <1 exacerbation/year (n=140), 1-2 exacerbations/year (n=160) and >2 exacerbations/year (n=146). Exacerbations were defined as acute/subacute worsening of respiratory symptoms severe enough to warrant oral or intravenous antibiotics. Patient-related factors associated with frequent exacerbations were determined, and clinical outcomes were compared among the three exacerbation groups. RESULTS: Patients with frequent exacerbations were more likely to be female, diabetic and have poorer baseline lung function. Patients with >2 exacerbations/year had an increased risk of experiencing a 5% decline from baseline forced expiratory volume in 1 s (FEV(1)); unadjusted HR 1.47 (95% CI 1.07 to 2.01, p=0.02), adjusted HR 1.55 (95% CI 1.10 to 2.18, p=0.01) compared with patients with <1 exacerbation/year. Patients with >2 exacerbations/year also had an increased risk of lung transplant or death over the 3 year study; unadjusted HR 12.74 (95% CI 3.92 to 41.36, p<0.0001), adjusted HR 4.05 (95% CI 1.15 to 14.28, p=0.03). CONCLUSIONS: Patients with CF with frequent exacerbations appear to experience an accelerated decline in lung function, and they have an increased 3 year risk of death or lung transplant.


Asunto(s)
Fibrosis Quística/fisiopatología , Adulto , Antibacterianos/administración & dosificación , Antibacterianos/uso terapéutico , Índice de Masa Corporal , Fibrosis Quística/complicaciones , Fibrosis Quística/mortalidad , Fibrosis Quística/cirugía , Progresión de la Enfermedad , Métodos Epidemiológicos , Femenino , Volumen Espiratorio Forzado/fisiología , Humanos , Inyecciones Intravenosas , Trasplante de Pulmón , Masculino , Ontario/epidemiología , Infecciones Oportunistas/complicaciones , Infecciones Oportunistas/tratamiento farmacológico , Selección de Paciente , Pronóstico , Factores Sexuales , Adulto Joven
6.
Am J Respir Crit Care Med ; 180(8): 761-8, 2009 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-19590021

RESUMEN

RATIONALE: We developed an evidence-based decision aid for patients with advanced cystic fibrosis considering referral for lung transplantation. OBJECTIVES: To prospectively evaluate whether use of the decision aid increased knowledge about the options, improved realistic expectations, and decreased decisional conflict in adult patients. METHODS: We performed a single-blind randomized controlled trial involving 149 adult patients with cystic fibrosis with an FEV(1)

Asunto(s)
Fibrosis Quística/cirugía , Toma de Decisiones Asistida por Computador , Conocimientos, Actitudes y Práctica en Salud , Trasplante de Pulmón/psicología , Participación del Paciente , Adulto , Fibrosis Quística/psicología , Técnicas de Apoyo para la Decisión , Femenino , Humanos , Masculino , Educación del Paciente como Asunto , Adulto Joven
7.
JAMA ; 304(19): 2145-53, 2010 Nov 17.
Artículo en Inglés | MEDLINE | ID: mdl-21081727

RESUMEN

CONTEXT: Studies from Australia and the United Kingdom have shown that some patients with cystic fibrosis are infected with common transmissible strains of Pseudomonas aeruginosa. OBJECTIVES: To determine the prevalence and incidence of infection with transmissible strains of P. aeruginosa and whether presence of the organism was associated with adverse clinical outcomes in Canada. DESIGN, SETTING, AND PARTICIPANTS: Prospective observational cohort study of adult patients cared for at cystic fibrosis clinics in Ontario, Canada, with enrollment from September 2005 to September 2008. Sputum was collected at baseline, 3 months, and yearly thereafter for 3 years; and retrieved P. aeruginosa isolates were genotyped. Vital status (death or lung transplant) was assessed for all enrolled patients until December 31, 2009. MAIN OUTCOME MEASURES: Incidence and prevalence of P. aeruginosa isolation, rates of decline in lung function, and time to death or lung transplantation. RESULTS: Of the 446 patients with cystic fibrosis studied, 102 were discovered to be infected with 1 of 2 common transmissible strains of P. aeruginosa at study entry. Sixty-seven patients were infected with strain A (15%), 32 were infected with strain B (7%), and 3 were simultaneously infected with both strains (0.6%). Strain A was found to be genetically identical to the Liverpool epidemic strain but strain B has not been previously described as an epidemic strain. The incidence rate of new infections with these 2 transmissible strains was relatively low (7.0 per 1000 person-years; 95% confidence interval [CI], 1.8-12.2 per 1000 person-years). Compared with patients infected with unique strains of P. aeruginosa, patients infected with the Liverpool epidemic strain (strain A) and strain B had similar declines in lung function (difference in decline in percent predicted forced expiratory volume in the first second of expiration of 0.64% per year [95% CI, -1.52% to 2.80% per year] and 1.66% per year [95% CI, -1.00% to 4.30%], respectively). However, the 3-year rate of death or lung transplantation was greater in those infected with the Liverpool epidemic strain (18.6%) compared with those infected with unique strains (8.7%) (adjusted hazard ratio, 3.26 [95% CI, 1.41 to 7.54]; P = .01). CONCLUSIONS: A common strain of P. aeruginosa (Liverpool epidemic strain/strain A) infects patients with cystic fibrosis in Canada and the United Kingdom. Infection with this strain in adult Canadian patients with cystic fibrosis was associated with a greater risk of death or lung transplantation.


Asunto(s)
Fibrosis Quística/complicaciones , Fibrosis Quística/microbiología , Infecciones por Pseudomonas/epidemiología , Pseudomonas aeruginosa/aislamiento & purificación , Adulto , Estudios de Cohortes , Femenino , Humanos , Incidencia , Trasplante de Pulmón , Masculino , Ontario/epidemiología , Prevalencia , Infecciones por Pseudomonas/transmisión , Pseudomonas aeruginosa/clasificación , Pseudomonas aeruginosa/genética , Factores de Riesgo , Análisis de Supervivencia , Resultado del Tratamiento , Reino Unido/epidemiología , Adulto Joven
8.
Chest ; 134(4): 794-800, 2008 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-18641106

RESUMEN

BACKGROUND: Patients with cystic fibrosis (CF) are at risk for early bone loss, and demonstrate increased risks for vertebral fractures and kyphosis. A multicenter, randomized, controlled trial was conducted to assess the efficacy, tolerability, and safety of therapy with oral alendronate (FOSAMAX; Merck; Whitehouse Station, NJ) in adults with CF and low bone mass. METHODS: Participants received placebo or alendronate, 70 mg once weekly, for 12 months. All participants received 800 IU of vitamin D and 1,000 mg of calcium daily. Adults with confirmed CF with a bone mineral density (BMD) T score of < - 1.0 were eligible for inclusion. Participants who had undergone organ transplantation or had other reported contraindications were excluded from the study. The primary outcome measure was the mean (+/- SD) percentage change in lumbar spine BMD after 12 months. Secondary measures included the percentage change in total hip BMD, the number of new vertebral fractures (grade 1 or 2), and changes in quality of life. RESULTS: A total of 56 participants were enrolled in the study (mean age, 29.1 +/- 8.78 years; 61% male). The absolute percentage changes in lumbar spine and total hip BMDs at follow-up were significantly higher in the alendronate therapy group (5.20 +/- 3.67% and 2.14 +/- 3.32%, respectively) than those in the control group (- 0.08 +/- 3.93% and - 1.3 +/- 2.70%, respectively; p < 0.001). At follow-up, two participants (both in the control group) had a new vertebral fracture (not significant), and there were no differences in quality of life or the number of adverse events (including serious and GI-related events). CONCLUSION: Alendronate therapy was well tolerated and produced a significantly greater increase in BMD over 12 months compared with placebo.


Asunto(s)
Alendronato/administración & dosificación , Conservadores de la Densidad Ósea/administración & dosificación , Fibrosis Quística/complicaciones , Vértebras Lumbares/lesiones , Osteoporosis/tratamiento farmacológico , Fracturas de la Columna Vertebral/prevención & control , Administración Oral , Adulto , Densidad Ósea , Canadá , Estudios de Cohortes , Método Doble Ciego , Esquema de Medicación , Femenino , Humanos , Masculino , Osteoporosis/complicaciones , Osteoporosis/diagnóstico , Fracturas de la Columna Vertebral/diagnóstico , Fracturas de la Columna Vertebral/epidemiología
9.
Lancet ; 366(9484): 463-71, 2005.
Artículo en Inglés | MEDLINE | ID: mdl-16084254

RESUMEN

BACKGROUND: We did a randomised, double-blind, controlled clinical trial to prospectively assess whether use of combination antibiotic susceptibility testing improved clinical outcomes in patients with acute pulmonary exacerbations of cystic fibrosis who were infected with multiresistant bacteria. METHODS: 251 patients with cystic fibrosis who were chronically infected with multiresistant gram negative bacteria gave sputum at 3-month intervals for conventional culture and sensitivity tests and for combination antibiotic susceptibility tests using multiple combination bactericidal antibiotic testing (MCBT). Patients who developed an exacerbation of pulmonary disease were randomised to receive a 14-day course of any two blinded intravenous antibiotics chosen on the basis of either results from conventional sputum culture and sensitivity testing or the result of MCBT. The primary outcome was time from randomisation until the patient's next pulmonary exacerbation. Analysis was by intention-to-treat. This study is registered as an International Standard Randomised Controlled Trial, number ISRCTN60187870. FINDINGS: 132 patients had a pulmonary exacerbation and were randomised during the 4.5-year study period. The time to next pulmonary exacerbation was not prolonged in the MCBT-treated group (hazard ratio 0.86 in favour of the conventionally-treated group, 95% CI 0.60-1.23, p=0.40). There was no difference between the groups in treatment failure rate. After 14 days of intravenous antibiotic therapy, changes in lung function, dyspnoea, and sputum bacterial density were similar in both groups. INTERPRETATION: Antibiotic therapy directed by combination antibiotic susceptibility testing did not result in better clinical and bacteriological outcomes compared with therapy directed by standard culture and sensitivity techniques. The non-bactericidal effects of antibiotic therapy might play an important part in determining improvement in patients with cystic fibrosis pulmonary exacerbations.


Asunto(s)
Antibacterianos , Fibrosis Quística/microbiología , Farmacorresistencia Bacteriana Múltiple , Pruebas de Sensibilidad Microbiana , Infecciones del Sistema Respiratorio/microbiología , Enfermedad Aguda , Adulto , Enfermedad Crónica , Fibrosis Quística/complicaciones , Método Doble Ciego , Quimioterapia Combinada , Femenino , Humanos , Masculino , Infecciones del Sistema Respiratorio/complicaciones , Infecciones del Sistema Respiratorio/tratamiento farmacológico , Esputo/microbiología
10.
Chest ; 129(4): 909-17, 2006 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-16608938

RESUMEN

BACKGROUND: Hospitalization rates for asthma vary more than threefold across regions of Ontario. It is not known whether this variation is primarily due to regional differences in the rate of emergency department (ED) visits or hospital admissions. OBJECTIVE: To determine the variation in ED visit rates for asthma in Ontario, and the relation between ED visit rates and hospitalization rates. DESIGN, SETTING, AND PATIENTS: We studied patients with an ED disposition diagnosis of asthma in a stratified sample of 16 hospitals (pediatric facilities, 13; adult facilities, 14) over a 1-year period. Pediatric patients were defined as those patients who were

Asunto(s)
Asma/terapia , Servicio de Urgencia en Hospital/estadística & datos numéricos , Admisión del Paciente/estadística & datos numéricos , Adolescente , Adulto , Distribución por Edad , Anciano , Asma/epidemiología , Áreas de Influencia de Salud , Niño , Preescolar , Femenino , Humanos , Lactante , Masculino , Persona de Mediana Edad , Ontario/epidemiología , Readmisión del Paciente/estadística & datos numéricos , Distribución por Sexo
11.
Waste Manag ; 46: 287-97, 2015 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-26303652

RESUMEN

This study aims to vaporize heavy metals and alkali/alkaline earth metals from two different types of fly ashes by thermal treatment method. Fly ash from a fluidized bed incinerator (HK fly ash) was mixed with one from a grate incinerator (HS fly ash) in various proportions and thermally treated under different temperatures. The melting of HS fly ash was avoided when treated with HK fly ash. Alkali/alkaline earth metals in HS fly ash served as Cl-donors to promote the vaporization of heavy metals during thermal treatment. With temperature increasing from 800 to 900°C, significant amounts of Cl, Na and K were vaporized. Up to 1000°C in air, less than 3% of Cl and Na and less than 5% of K were retained in ash. Under all conditions, Cd can be vaporized effectively. The vaporization of Pb was mildly improved when treated with HS fly ash, while the effect became less pronounced above 900°C. Alkali/alkaline earth metals can promote Cu vaporization by forming copper chlorides. Comparatively, Zn vaporization was low and only slightly improved by HS fly ash. The low vaporization of Zn could be caused by the formation of Zn2SiO4, ZnFe2O4 and ZnAl2O4. Under all conditions, less than 20% of Cr was vaporized. In a reductive atmosphere, the vaporization of Cd and Pb were as high as that in oxidative atmosphere. However, the vaporization of Zn was accelerated and that of Cu was hindered because the formation of Zn2SiO4, ZnFe2O4 and ZnAl2O4 and copper chloride was depressed in reductive atmosphere.


Asunto(s)
Álcalis/análisis , Ceniza del Carbón/química , Incineración , Metales Alcalinotérreos/análisis , Metales Pesados/química , Residuos Sólidos/análisis , Temperatura , Volatilización
12.
J Appl Physiol (1985) ; 117(3): 297-306, 2014 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-24903918

RESUMEN

Hyperpolarized (3)He MRI previously revealed spatially persistent ventilation defects in healthy, older compared with healthy, younger never-smokers. To understand better the physiological consequences and potential relevance of (3)He MRI ventilation defects, we evaluated (3)He-MRI ventilation-defect percent (VDP) and the effect of deep inspiration (DI) and salbutamol on VDP in older never-smokers. To identify the potential determinants of ventilation defects in these subjects, we evaluated dyspnea, pulmonary function, and cardiopulmonary exercise test (CPET) measurements, as well as occupational and second-hand smoke exposure. Fifty-two never-smokers (71 ± 6 yr) with no history of chronic respiratory disease were evaluated. During a single visit, pulmonary function tests, CPET, and (3)He MRI were performed and the Burden of Obstructive Lung Disease questionnaire administered. For eight of 52 subjects, there was spirometry evidence of airflow limitation (Global Initiative for Chronic Obstructive Lung Disease-Unclassified, I, and II), and occupational exposure was reported in 13 of 52 subjects. In 13 of 52 (25%) subjects, there were no ventilation defects and in 39 of 52 (75%) subjects, ventilation defects were observed. For those subjects with ventilation defects, six of 39 showed a VDP response to DI/salbutamol. Ventilation heterogeneity and VDP were significantly greater, and forced expiratory volume in 1 s (FEV1)/forced vital capacity was significantly lower (P < 0.05) for subjects with ventilation defects with a response to DI/salbutamol than subjects with ventilation defects without a response to DI/salbutamol and subjects without ventilation defects. In a step-wise, forward multivariate model, FEV1, inspiratory capacity, and airway resistance significantly predicted VDP (R(2) = 0.45, P < 0.001). In conclusion, most never-smokers had normal spirometry and peripheral ventilation defects not reversed by DI/salbutamol; such ventilation defects were likely related to irreversible airway narrowing/collapse but not to dyspnea and decreased exercise capacity.


Asunto(s)
Pulmón/fisiopatología , Ventilación Pulmonar/fisiología , Fumar/fisiopatología , Anciano , Albuterol/farmacología , Femenino , Volumen Espiratorio Forzado/efectos de los fármacos , Volumen Espiratorio Forzado/fisiología , Helio/administración & dosificación , Humanos , Inhalación/efectos de los fármacos , Inhalación/fisiología , Pulmón/efectos de los fármacos , Imagen por Resonancia Magnética/métodos , Masculino , Enfermedad Pulmonar Obstructiva Crónica/fisiopatología , Ventilación Pulmonar/efectos de los fármacos , Pruebas de Función Respiratoria/métodos
13.
J Appl Physiol (1985) ; 114(6): 707-15, 2013 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-23239874

RESUMEN

In subjects with chronic obstructive pulmonary disease (COPD), hyperpolarized xenon-129 ((129)Xe) magnetic resonance imaging (MRI) reveals significantly greater ventilation defects than hyperpolarized helium-3 ((3)He) MRI. The physiological and/or morphological determinants of ventilation defects and the differences observed between hyperpolarized (3)He and (129)Xe MRI are not yet understood. Here we aimed to determine the structural basis for the differences in ventilation observed between (3)He and (129)Xe MRI in subjects with COPD using apparent diffusion coefficients (ADC) and computed tomography (CT). Ten COPD ex-smokers provided written, informed consent and underwent MRI, CT, spirometry, and plethysmography. (3)He and (129)Xe MRI ventilation volume was generated using semiautomated segmentation, and ADC maps were registered to generate ADC values for lung regions of interest ventilated by both gases (ADCHX) and by (3)He gas only (ADCHO). CT wall area percentage and the lowest 15th percentile point of the CT lung density histogram (HU15%) were also evaluated. For lung regions accessed by (3)He gas only, mean (3)He ADCHO was significantly greater than for regions accessed by both gases (ADCHO = 0.503 ± 0.119 cm(2)/s, ADCHX = 0.470 ± 0.125 cm(2)/s, P < 0.0001). The difference between (3)He and (129)Xe ventilation volume was significantly correlated with CT HU15% (r = -65, P = 0.04) and (3)He ADCHO (r = 0.70, P = 0.02), but not CT wall area percentage (r = -0.34, P = 0.33). In conclusion, in this small study in COPD subjects, we observed significantly decreased (129)Xe MRI ventilation compared with (3)He MRI, and these regions of decreased (129)Xe ventilation were spatially and significantly correlated with regions of increased pulmonary emphysema, but not airway wall thickness.


Asunto(s)
Medios de Contraste , Imagen de Difusión por Resonancia Magnética , Helio , Pulmón/fisiopatología , Enfermedad Pulmonar Obstructiva Crónica/diagnóstico , Enfisema Pulmonar/diagnóstico , Ventilación Pulmonar , Isótopos de Xenón , Anciano , Anciano de 80 o más Años , Análisis de Varianza , Femenino , Humanos , Pulmón/diagnóstico por imagen , Masculino , Persona de Mediana Edad , Pletismografía , Valor Predictivo de las Pruebas , Enfermedad Pulmonar Obstructiva Crónica/diagnóstico por imagen , Enfermedad Pulmonar Obstructiva Crónica/fisiopatología , Enfisema Pulmonar/diagnóstico por imagen , Enfisema Pulmonar/fisiopatología , Índice de Severidad de la Enfermedad , Relación Señal-Ruido , Espirometría , Tomografía Computarizada por Rayos X
14.
Acad Radiol ; 19(8): 941-51, 2012 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-22591724

RESUMEN

RATIONALE AND OBJECTIVES: The objective of this study was to evaluate the tolerability of hyperpolarized (129)Xe gas inhaled from functional residual capacity and magnetic resonance imaging in healthy subjects and those with pulmonary disease. MATERIALS AND METHODS: Twelve healthy volunteers (mean age, 59 ± 17 years), seven subjects with asthma (mean age, 47 ± 7 years), 10 subjects with chronic obstructive pulmonary disease (mean age, 74 ± 4 years), three subjects with cystic fibrosis (mean age, 27 ± 10 years), and a single subject with radiation-induced lung injury (age, 66 years) were enrolled and evaluated over 43 visits with 136 anoxic inhalations of 500 mL (129)Xe gas mixed with 500 mL (4)He gas. Oxygen saturation and heart rate were monitored during the breath-hold and imaging; subjects were queried for adverse events (AEs) before and immediately following gas inhalation and for 24 hours after the last dose. RESULTS: No subjects withdrew from the study or reported serious, hypoxic, or severe AEs. Over the course of 136 dose administrations, two mild AEs (1%) were reported in two different subjects (two of 33 [6%]). One of these AEs (light-headedness) was temporally related and judged as possibly related to (129)Xe administration and resolved without treatment within 2 minutes. Statistically significant but clinically insignificant changes in oxygen saturation and heart rate were observed after inhalation (P < .001), and both resolved 1 minute later, with no difference between subject groups. CONCLUSIONS: Inhalation of hyperpolarized (129)Xe gas and subsequent magnetic resonance imaging were well tolerated in healthy subjects and ambulatory subjects with obstructive and restrictive pulmonary disease.


Asunto(s)
Medios de Contraste/efectos adversos , Enfermedades Pulmonares/diagnóstico , Imagen por Resonancia Magnética/métodos , Isótopos de Xenón/efectos adversos , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Adulto Joven
15.
PLoS One ; 7(4): e36077, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22563440

RESUMEN

BACKGROUND: Many patients with cystic fibrosis develop persistent airway infection/colonization with Aspergillus fumigatus, however the impact of A. fumigatus on clinical outcomes remains unclear. The objective of this study was to determine whether treatment directed against Aspergillus fumigatus improves pulmonary function and clinical outcomes in patients with cystic fibrosis (CF). METHODS: We performed a double-blind randomized placebo-controlled pilot clinical trial involving 35 patients with CF whose sputum cultures were chronically positive for A. fumigatus. Participants were centrally randomized to receive either oral itraconazole 5 mg/kg/d (N = 18) or placebo (N = 17) for 24 weeks. The primary outcome was the proportion of patients who experienced a respiratory exacerbation requiring intravenous antibiotics over the 24 week treatment period. Secondary outcomes included changes in FEV(1) and quality of life. RESULTS: Over the 24 week treatment period, 4 of 18 (22%) patients randomized to itraconazole experienced a respiratory exacerbation requiring intravenous antibiotics, compared to 5 of 16 (31%) placebo treated patients, P = 0.70. FEV(1) declined by 4.62% over 24 weeks in the patients randomized to itraconazole, compared to a 0.32% improvement in the placebo group (between group difference = -4.94%, 95% CI: -15.33 to 5.45, P = 0.34). Quality of life did not differ between the 2 treatment groups throughout the study. Therapeutic itraconazole blood levels were not achieved in 43% of patients randomized to itraconazole. CONCLUSION: We did not identify clinical benefit from itraconazole treatment for CF patients whose sputum was chronically colonized with A. fumigatus. Limitations of this pilot study were its small sample size, and failure to achieve therapeutic levels of itraconazole in many patients. TRIAL REGISTRATION: ClinicalTrials.gov NCT00528190.


Asunto(s)
Aspergillus fumigatus/patogenicidad , Fibrosis Quística/tratamiento farmacológico , Administración Oral , Adolescente , Adulto , Antifúngicos/uso terapéutico , Aspergilosis/complicaciones , Aspergilosis/tratamiento farmacológico , Niño , Fibrosis Quística/complicaciones , Fibrosis Quística/fisiopatología , Método Doble Ciego , Femenino , Volumen Espiratorio Forzado , Hospitalización , Humanos , Inyecciones Intravenosas , Itraconazol/uso terapéutico , Pulmón/fisiopatología , Masculino , Proyectos Piloto , Efecto Placebo , Calidad de Vida , Pruebas de Función Respiratoria , Esputo/microbiología , Factores de Tiempo , Adulto Joven
16.
Acad Radiol ; 18(8): 1006-13, 2011 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-21536462

RESUMEN

RATIONALE AND OBJECTIVES: To better understand imaging measurement precision and reproducibility and to provide guidance for measurements in individual cystic fibrosis (CF) subjects, we evaluated CF adults on two occasions 7 ± 2 days apart using spirometry, plethysmography, and hyperpolarized helium-3 ((3)He) magnetic resonance imaging (MRI). MATERIALS AND METHODS: Twelve CF subjects underwent spirometry, plethysmography, and (3)He MRI twice within 7 ± 2 days, reporting (3)He ventilation defect volume (VDV) and ventilation defect percent (VDP). RESULTS: Based on measurement variability, the smallest detectable difference (SDD) for (3)He VDV and VDP was determined to be 120 mL and 2%, respectively. Although no significant difference in spirometry or plethysmography was detected after 7 days, there was a significant difference in mean (3)He VDV (130 mL ± 250 mL, P < .0001) and VDP (3% ± 4%, P < .0001), although baseline and 7-day measurements were highly correlated (VDV: r = .85, P = .001; VDP: r = .94, P < .0001). We estimated the sample sizes required to detect a 5%/7%/10% change in (3)He VDP as 60/15/5 subjects per group. CONCLUSION: Hyperpolarized (3)He MRI VDP measurement precision resulted in an SDD for individual CF subjects of 2%, indicating that changes greater than this can be attributed to lung functional changes and not measurement error. After 7 days, significant changes in mean (3)He VDV and VDP were detected and these changes were not reflected by changes in pulmonary function measurements. These findings demonstrate the high sensitivity and reproducibility of (3)He MRI functional imaging that permits the use of relatively small samples sizes in CF interventional studies.


Asunto(s)
Fibrosis Quística/fisiopatología , Helio , Imagen por Resonancia Magnética/métodos , Adolescente , Adulto , Femenino , Humanos , Interpretación de Imagen Asistida por Computador , Isótopos , Masculino , Persona de Mediana Edad , Reproducibilidad de los Resultados , Pruebas de Función Respiratoria
17.
Chest ; 135(3): 724-736, 2009 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-19017869

RESUMEN

BACKGROUND: Variation in hospitalization rates for acute asthma in Ontario may reflect gaps between evidence and current emergency department (ED) management. We investigated ED management of asthma and differences in practice patterns for pediatric (< 20 years old) and adult (> or = 20 years old) patients in Ontario EDs. METHOD: Patient characteristics and ED management during a 1-year period were assessed by questionnaire and chart abstractions in a stratified sample of 16 Ontario hospitals. Variation between sites was assessed by one-way analysis of variance, Kruskal-Wallis test, or chi(2) test. RESULTS: Reported results are based on the first of 2,671 pediatric (42.0% female) and 2,078 adult (66.7% female) visits with a corresponding questionnaire. Asthma severity, comorbidities, access to care, and prehospital management varied significantly among sites (all p < 0.001). Documentation of peak expiratory flow (27.2% of pediatric [age > or = 7] and 44.3% of adult charts), use of systemic steroids in ED (35.2% pediatric and 33.0% adult charts) and on discharge (31.7% pediatric and 33.2% adult charts), and referrals to asthma services (2.8% pediatric and 2.7% adult charts) varied among sites (all p < 0.001). Admission (%) was directly related to time to receive systemic steroids in ED in adults (r = 0.76; p = 0.004). Repeat ED visits (%) were inversely related to new inhaled steroid prescription on discharge in adults (r = -0.64; p = 0.02). CONCLUSIONS: Knowledge translation initiatives are warranted to increase adherence with best practices in emergency management of asthma (such as objective assessment of airflow rates, use of systemic steroids, and referrals) in order to reduce variations in care and improve outcomes of severe acute asthma.


Asunto(s)
Asma/terapia , Servicio de Urgencia en Hospital , Enfermedad Aguda , Adolescente , Adulto , Antiasmáticos/uso terapéutico , Asma/diagnóstico , Niño , Preescolar , Femenino , Glucocorticoides/uso terapéutico , Adhesión a Directriz , Hospitalización , Humanos , Masculino , Ontario , Guías de Práctica Clínica como Asunto , Derivación y Consulta
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