American journal of respiratory and critical care medicine
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Am. J. Respir. Crit. Care Med. · Dec 2000
Fibroblast contractility: usual interstitial pneumonia and nonspecific interstitial pneumonia.
The aim of this study was to compare the function of lung fibroblasts obtained from surgically biopsied specimens of patients with idiopathic pulmonary fibrosis/usual interstitial pneumonia (UIP; n = 5), nonspecific interstitial pneumonia (NSIP; n = 5), and normal parts of surgically resected lungs (control; n = 5). The results showed that (1) fibroblasts obtained from UIP showed increased contractility compared with those obtained from NSIP or controls (UIP, 72.7 +/- 6.21%; NSIP, 32.8 +/- 5.46; controls, 28.5 +/- 3.51, p < 0.01 in UIP versus NSIP or control); (2) this increase in contractility was consistent with enhanced F-actin content in fibroblasts; (3) conditioned media from UIP fibroblast cultures enhanced control fibroblast contractility, whereas those obtained from NSIP or controls did not; (4) the 180 and 25 kD products representing the contractility in conditioned media were identified as fibronectin (ED-A domain) and TGF-beta1 by immunoblots, respectively; (5) the UIP-conditioned media contained higher amounts of fibronectin or TGF-beta 1 (fibronectin: UIP 289 +/- 47.1 ng/ml, NSIP 121 +/- 23.0, control 118 +/- 16.0; TGF-beta1: UIP 798 +/- 119 pg/ml, NSIP 246 +/- 69.1, control 247 +/- 53.6, p < 0.01 in UIP versus NSIP or control); () the contractility positively correlated with the amount of either fibronectin (r = 0.867, p < 0.001, n = 15) or TGF-beta 1 (r = 0.939, p < 0.001, n = 15), respectively. Thus, UIP fibroblasts showed greater contractility than did NSIP fibroblasts and up-regulated control fibroblasts.
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Am. J. Respir. Crit. Care Med. · Dec 2000
Therapeutic hypercapnia reduces pulmonary and systemic injury following in vivo lung reperfusion.
Permissive hypercapnia, involving tolerance to elevated Pa(CO(2)), is associated with reduced acute lung injury (ALI), thought to result from reduced mechanical stretch, and improved outcome in ARDS. However, deliberately elevating inspired CO(2) concentration alone (therapeutic hypercapnia, TH) protects against ALI in ex vivo models. We investigated whether TH would protect against ALI in an in vivo model of lung ischemia-reperfusion (IR). ⋯ Finally, preliminary data suggest that TH may attenuate apoptosis following lung IR. We conclude that in the current model TH is protective versus IR lung injury and mechanisms of protection include preservation of lung mechanics, attenuation of pulmonary inflammation, and reduction of free radical mediated injury. If these findings are confirmed in additional models, TH may become a candidate for clinical testing in critical care.
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Am. J. Respir. Crit. Care Med. · Dec 2000
Comparative Study Clinical TrialOptimization of aerosol deposition by pressure support in children with cystic fibrosis: an experimental and clinical study.
Nebulized aerosols are commonly used to deliver drugs into the lungs of patients with cystic fibrosis (CF). The aim of this study was to assess the effectiveness of pressure-support (PS) ventilation in increasing aerosol deposition within the lungs of children with CF. An in vitro study demonstrated the feasibility of coupling a breath-actuated nebulizer to a PS device. ⋯ Similarly, deposition efficacy (as a percentage of nebulizer output) was significantly better during the PS session than during the control session (15.3 +/- 8.3% versus 11.5 +/- 5.7%, p < 0.05). No differences in the regional deposition pattern or in homogeneity of uptake were observed. In conclusion, our data show that driving the delivery of a nebulized aerosol by noninvasive PS ventilation enhances total lung aerosol deposition without increasing particle impaction in the proximal airways.
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Am. J. Respir. Crit. Care Med. · Dec 2000
Multicenter StudyOutcomes of contact investigations of infectious tuberculosis patients.
The objective of this study was to describe outcomes of tuberculosis (TB) contact investigations, factors correlated with those outcomes, and current successes and ways to improve TB contact investigations. We abstracted clinic records of a representative U. S. urban sample of 1,080 pulmonary, sputum-smear(+) TB patients reported to CDC July 1996 through June 1997 and the cohort of their 6,225 close contacts. ⋯ Using directly observed treatment (DOT) increased the likelihood of treatment completion. We documented outcomes of contact investigation efforts by urban TB programs. We identified several successful practices, as well as suggestions for improvements, that will help TB programs target policies and procedures to enhance contact investigation effectiveness.
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Am. J. Respir. Crit. Care Med. · Dec 2000
Comparative StudyEffects of in utero and environmental tobacco smoke exposure on lung function in boys and girls with and without asthma.
To investigate whether the effects of in utero exposure to maternal smoking and environmental tobacco smoke (ETS) exposure on lung function vary by sex or asthma status, we examined medical history and tobacco smoke exposure data for 5,263 participants in the Children's Health Study. At study enrollment, parents or guardians of each subject completed a questionnaire, and lung function was measured spirometrically with maximum forced expiratory flow-volume maneuvers. To assess the in utero effects of maternal smoking and ETS exposure on lung function, we used regression splines that accounted for the nonlinear relationship between pulmonary function, height, and age. ⋯ In contrast, past ETS exposure was associated with decreased flow rates in girls without asthma. In summary, both in utero exposure to maternal smoking and ETS exposure were associated with persistent deficits in lung function. The effects of in utero exposure were greatest among children with asthma.