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Query: UMLS:C0034067 (emphysema)
 11,506 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To assess whether the slope of phase III of the single breath nitrogen (SB-N2) test correlates better with inhomogeneity of the elastic properties within a lung or with peripheral airway inflammation, pressure-volume (PV) curves and SB-N2 tests were performed in 28 excised human lungs, including 11 emphysema-free and 17 emphysematous lungs. The degrees of emphysema and membranous as well as respiratory bronchiolar inflammation were graded in a semi-quantitative manner. The PV curves were analysed using an exponential curve fit, yielding the exponent K which is proportional to total incremental compliance. In the 11 emphysema-free lungs, the slope of phase III was significantly correlated with K, when both age (p less than 0.05) and bronchiolar inflammation scores (p less than 0.01) were held constant. On the other hand, the slope of phase III correlated less favourably with the bronchiolar inflammation scores when age was held constant and was not significantly correlated with the bronchiolar inflammation scores when K was held constant. In the emphysematous lungs alone, or when the emphysema-free and emphysematous lungs were pooled, these correlations disappeared. In 23 smoking subjects, the slope of phase III was also significantly correlated with K (r = 0.72; p less than 0.001). We conclude that in emphysema-free lungs the slope of phase III is better correlated with the overall elastic properties of the lungs than with bronchiolar inflammation, and we speculate that increases in K, implying a greater overall curvature of the PV relationship, reflect increasing inhomogeneity of elastic properties within a lung, rather than a uniform change affecting individual lung units equally.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Determinants of the slope of phase III of the single breath nitrogen test. 651 15

An elastase-induced emphysema model was utilized to determine if hamsters with preexisting lung disease were more susceptible to lung damage from air pollutant exposure. Male golden hamsters, divided into two treatment groups, were given a single intratracheal injection of either 6 units of porcine pancreatic elastase (EMP) or buffer (CNT). After a 4-week recovery period, equal numbers of each group were exposed 23 hr/day X 28 day to filtered air (AIR) or to the complex by-products from a dark phase reaction mixture of trans-2-butene, ozone, and sulfur dioxide (MIX). Lung function measurements on the elastase-treated groups showed changes consistent with mild emphysema. There were no significant differences in lung volumes or lung compliance between the AIR- and MIX-exposed animals. However, the nitrogen washout slope decreased (P less than 0.05), and the diffusing capacity for carbon monoxide increased (P less than 0.05) in both the CNT and EMP hamsters exposed to the MIX. The change in diffusing capacity was greater (P less than 0.05) in normal hamsters than in hamsters with emphysema, and it is hypothesized that animals with impaired lung function had a decreased ability to respond to a pulmonary insult from the mix.
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PMID:Pulmonary function in normal and elastase-treated hamsters exposed to a complex mixture of olefin-ozone-sulfur dioxide reaction products. 655 1

The long-term consequences of acute lung injury during critical growth periods of the lung were evaluated by inducing mild bronchiolitis with nitrogen dioxide (NO2) in 3-day-old (newborn) and 21-day-old (young) hamsters. Hamsters were exposed to 30 ppm NO2 for 7 days. Age-matched animals exposed to room air served as controls. Lung volumes, static deflationary pressure-volume curves, mean linear intercept, and internal surface area were measured when the animals reached 1 yr of age. Newborns exposed to NO2 showed an increased volume at 25 cm H2O pressure (V25) adjusted for body weight, a decreased transpulmonary pressure at 60% of V25, and an increased mean linear intercept when compared with control animals. The internal surface area was less than that in the control animals; the difference approached significance. In the young exposed group there were no differences for any measurements when compared with the control group. These data indicate that a mild injury imposed during the newborn period may result in physiologic and morphometric changes that simulate mild emphysema in the mature animal.
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PMID:Long-term sequelae of bronchiolitis induced by nitrogen dioxide in hamsters. 665 Sep 73

A new isotope method for the determination of the residual volume of the lungs by means of stable, non-radioactive nitrogen isotope 15N is described. Normal air is breathed in a closed system. One part of the air nitrogen is replaced by 15N labelled molecular nitrogen. 15N2 physiologically acts like normal nitrogen so that the so-called secondary effects by using He or H2 are eliminated. By combination of a spirograph and an emission spectrometric 15N analyser the residual volume can be determined and mixing curves can be obtained. The determination of the residual volume in 10 healthy persons gives a range of normal values from 19 to 31% of the total capacity. In three persons with emphysema values from 45 to 50% of the total capacity are found. The analysis of mixing curves leads to additional informations concerning the intrapulmonary gas mixing conditions in the lungs. The relative error of the residual volume determination is about 8%.
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PMID:[A new isotope technic for the determination of residual volume]. 674 Nov 73

A patient with pronounced dyspnoea and cyanosis was found to have severe hypoxaemia with normal spirographic values. His past history included arterial hypertension, myocardial infarction and phlebitis of the lower limb. Airways resistance was normal, but maximal expiratory flow rates at low lung volume (Flow-volume curves) were reduced, suggesting "peripheral" airways obstruction. This was confirmed by the presence of pulmonary hyperinflation and mechanical non-homogeneity accompanied by unevenly distributed ventilation, as shown by alveolar nitrogen gradient. There was marked hyperventilation with hypocapnia. Since transfer values (measured by the CO single-breath method) and lung distensibility values were normal, emphysema could be ruled out as a cause of obstruction. Analysis of pressure-flow relationship confirmed that the obstruction of peripheral airways was "intrinsic" in character. It could be due to an increase in lung extravascular fluid (interstitial oedema due to left cardiac failure), or to repeated micro-emboli in the lungs, or to hypocapnia, these three mechanisms possibly being associated.
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PMID:[Peripheral airway obstruction involving cardiovascular factors. A case report (author's transl)]. 677 51

A simple means of functional classification of the individual patient has been devised. The performance of a forced flow-volume manoeuvre in concert with a single-breath nitrogen washout procedure in 54 comprehensively investigated patients with chronic airflow limitation yielded two parameters which could be employed in classification. A normalized alveolar nitrogen slope (FEV1/FVC X delta N2%) greater than 4.0% per litre clearly delineated emphysema. The peak flow ratio (PEFR/PIFR%) categorized other subgroupings: a value in excess of 100% strongly suggests primary bronchial disease, while a lower value almost certainly indicates a mixed functional disorder.
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PMID:Functional classification of chronic airflow limitation based on flow-volume and single-breath nitrogen washout criteria. 682 1

Elastase-induced emphysema in hamsters was studied using pulmonary function tests in an effort to develop techniques for determining the effects of air pollutants on the progression of this disease. Single intratracheal injections of 6, 12, or 24 units of porcine pancreatic elastase produced dose-related changes in pulmonary function after 4 wk when compared with sham-injected control animals. Boyle's law end-expiratory volume and residual volume, measured by gas dilution, increased (p less than 0.05) at 12 and 24 units, respectively, whereas vital capacity, determined plethysmographically, and total lung capacity wee increased (p less than 0.05) at all 3 elastase doses. Respiratory system compliance, calculated by a nonlinear least squares regression fit of the deflation pressure-volume curve, increased (p less than 0.05) at 24 units only. The multiple-breath nitrogen washout slope (N2 slope) and the single-breath diffusing capacity for carbon monoxide (DLCO) decreased (p less than 0.05) at all 3 doses of elastase. Both histologic and physiologic evaluation showed dose-related pulmonary impairment. It appears, therefore, that as little as 6 units of elastase produces mild emphysema in hamsters, which is detectable by pulmonary function testing. Of these tests, the DLCO and N2 slope were the most effective in detecting the degree of impairment.
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PMID:Dose response of elastase-induced emphysema in hamsters. 691 2

The diagnostic value of different respiratory function tests in the respiratory distress syndrome was compared in 5 groups of subjects: healthy non-smokers, asymptomatic smokers, patients with bronchitis affecting the large bronchi, asthmatic patients between attacks, and patients with emphysema. Indices measured were the forced expiratory volume per second (FEV1), mean expiratory flow between 25 and 75% of vital capacity (MEF 25-75%), maximum instantaneous flow at 25-50-75% of vital capacity, and peak flow (Vmax 25-50-75%, PF), residual volume, expiratory resistance volume, and the curve of the alveolar plateau of expired nitrogen. The Vmax 50% and the MEF 25-75% appear to be sufficiently sensitive indices of bronchial obstruction in current practice, the MEF 25-75% being simple to measure, and presenting the advantage of not requiring complicated equipment. The Vmax 25% and the respiratory resistance volume present wide inter-individual variations, and this, together with their lack of reproducibility, limit their value in exploratory tests in isolated cases.
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PMID:[Comparative value of different respiratory function tests for the early diagnosis of the respiratory distress syndrome (author's transl)]. 708 68

Pressure-volume (PV) curves and single-breath nitrogen (SBN) washout traces were obtained in 32 excised human lungs. Comparison of the volumes at the onset of phage IV of the SBN traces (V phase IV) and the volumes at the inflection points (VIP) of the PV curves revealed V phase IV to be significantly larger than VIP. We postulated that V phase IV was caused by bulk airway closure and that the difference between V phase IV and VIP was due to collateral ventilation. To test this we correlated V phas IV -- VIP with age and emphysema grades of the lungs. Significant correlations were obtained, demonstrating that with increasing age and emphysema grade V phase IV -- VIP also increased. This is consistent with the documented evidence for decreased resistance to collateral ventilation with increasing age and emphysema. In addition, in a total of 86 lungs we demonstrated that with increasing age and emphysema there is an increasing incidence of total lack of sigmoid deviation in the PV curve.
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PMID:Collateral ventilation in excised human lungs. 722 64

The relation between mold to moderate emphysema and lung function tests, including tests reported to identify "early" or mild disease, were examined using 24 excised human lungs, 5 with no emphysema, 11 with grade 5 or less emphysema, and 8 with as much as grade 50 emphysema. Static pressure volume curves, single breath nitrogen (SBN2) tests, maximal exemphysema. Static pressure volume curves, single breath nitrogen (SBN2) tests, maximal expiratory flow volume (MEFV) curves with air and a mixture of 80% He and 20% O22, and forced expiratory volume in one second (FEV1) were measured in all lungs. Negative correlations were found (r - -0.489, p less than 0.02) between the emphysema grade and the per cent predicted static lung recoil at 50% of total lung capacity and the emphysema grade and the per cent predicted FEV1 (r = 0.428, p less than 0.05). There was no significant correlation between the grade of emphysema and the SBN2, or MEFV test. Negative correlations were found between the elastic recoil, expressed as per cent predicted slope of Phase III (r = 0.482 p less than 0.02), and the per cent predicted FEV1 (r = -0.619, p less than 0.01). We concluded that mild to moderate degrees of emphysema are not correlated with single breath nitrogen test or flow volume curves using air or helium, but are better related to loss of elastic recoil in excised human lungs.
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PMID:Functional correlations with mild and moderate emphysema in excised human lungs. 731 75


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