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

The slope of alveolar plateau for nitrogen derived from the single-breath test is useful to assess the function of bilateral lung grafts, but this technique is not applicable to patients with single-lung grafts due to the confounding influence of the native lung. We tested the hypothesis that the nitrogen slope measured in lateral decubitus with the graft in nondependent position may primarily reflect the distribution of ventilation in this lung. Fifteen patients with single-lung transplantation for emphysema, 10 healthy controls, and 7 patients with advanced emphysema performed single-breath washouts in right and left lateral decubitus; nitrogen slope was measured between 75 and 100% of expired volume. In 10 transplant recipients, the volume of each lung was measured in the two postures by computerized tomography. Nitrogen slope was unaffected by posture in normal controls and emphysema patients. On the other hand, nitrogen slope in transplant recipients was invariably smaller, with the graft in nondependent vs. in dependent position. Values of nitrogen slope with the graft in nondependent position were similar to those obtained in normal controls but significantly smaller than those obtained in emphysema patients. Computerized tomography studies in this position indicated that the volume expired below functional residual capacity was exclusively contributed by the graft. We conclude that, in patients with single-lung transplantation for emphysema, 1) measuring nitrogen slope in lateral decubitus allows to distinguish between the graft and the native lung, and 2) nitrogen slope obtained with the graft in nondependent position reflects ventilation distribution in this lung.
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PMID:Single-breath test in lateral decubitus reflects function of single lungs grafted for emphysema. 1630 51

Chronic obstructive pulmonary disease (COPD) is a smoking-related disorder that is a leading cause of death worldwide. It is associated with an accelerated rate of age-related decline in lung function due to the occurrence of destructive pathological changes such as emphysema, small airway remodeling, and mucus hypersecretion. Smokers are exposed to trillions of radicals and thousands of reactive chemicals and particles with every cigarette, thus oxidant stress is believed to be a central factor in the pathogenesis of COPD. The molecular activities of radicals, reactive oxygen, and nitrogen species can, over time, lead to a number of the detrimental changes in the lung. For instance, smoke can directly damage the mitochondrion, an organelle that has long been linked to age-related diseases associated with oxidant stress. Mitochondria are involved in a number of important cellular processes and are the largest source of endogenous reactive oxygen species (ROS) in the cell; therefore, any impairment of mitochondrial function can lead to greater oxidant damage, cellular dysfunction, and eventually to disease. Only a subset of smokers (15-50%) develops COPD, suggesting that there are polygenetic and/or environmental susceptibility factors involved in this complex disease. Here, we propose that the aerobic capacity for an individual may determine whether one is susceptible to developing COPD. Aerobic capacity is a polygenetic trait closely associated with mitochondrial function, and we suggest antioxidant defenses. Thus, those smokers who have the greatest aerobic capacity will be most resistant to the effects of chronic cigarette smoke exposure and be less likely to develop COPD.
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PMID:Aerobic capacity, oxidant stress, and chronic obstructive pulmonary disease--a new take on an old hypothesis. 1634 38

The slope of phase III of the single-breath nitrogen wash-out test (sbN2-test) measures ventilation inhomogeneity and, in smokers, is strongly associated with small airways pathology. The present authors aimed to study ventilation inhomogeneity in emphysema related to type Z alpha1-antitrypsin (AAT) and to assess its relationship with indices of parenchymal damage and airways obstruction. A total of 18 subjects, consisting of ex-smokers with type Z AAT and emphysema (confirmed by computed tomography scan), were studied in a cross-sectional design. Post-bronchodilation flow-volume curves and gas transfer parameters were measured; sbN2-test curves were obtained and the slope of phase III was determined. The mean value of the slope (4.6+/-1.3% N2 x L(-1)) was higher than reference values +2sd; it was significantly correlated with the transfer factor of the lung for carbon monoxide (R = -0.75) and the transfer coefficient of the lung for carbon monoxide (R = -0.58), but not with airways obstruction. There was no correlation between phase III slope values and cumulative smoking. In patients with type Z alpha1-antitrypsin emphysema, the increased ventilation inhomogeneity predominantly reflects parenchymal abnormalities, demonstrating that measurement of airways obstruction is not sufficient to characterise the disease. Determination of the sensitivity of the single-breath nitrogen wash-out test slope in detecting disease progression may give complementary information to spirometry.
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PMID:Ventilation inhomogeneity in alpha1-antitrypsin-deficient emphysema. 1657 11

After single-lung transplantation (SLT) for emphysema, heterogeneity of ventilation distribution in the graft can be assessed by measuring the slope of the alveolar plateau, computed from a single-breath test, performed in lateral decubitus with this lung in the nondependent position. We tested the validity of this technique in patients with SLT for interstitial lung diseases (ILD). Twelve patients with SLT for ILD, 12 nontransplanted patients with ILD, and 10 healthy control subjects performed single-breath washouts in right and left lateral decubitus; nitrogen slope (S(N(2))) and the difference between SF(6) and He slopes (S(SF(6))-S(He)) were measured between 75 and 100% of expired volume. In 10 transplant recipients, the volume of each lung was measured in both postures by computerized tomography. Slopes were unaffected by posture in normal control subjects and patients with ILD. On the other hand, S(N(2)) and S(SF(6))-S(He) in transplant recipients were smaller with the graft in the nondependent than in the dependent position (0.366 +/- 0.445 vs. 1.035 +/- 0.498 for S(N(2)); 0.094 +/- 0.201 vs. 0.218 +/- 0.277 for S(SF(6))-S(He)). Values of S(N(2)) and S(SF(6))-S(He) obtained in the former position were similar to those obtained in normal controls, while values obtained in the latter position were similar to those obtained in nontransplanted patients with ILD. Computerized tomography studies with the graft in the nondependent position indicated that this lung contributed 82% of the volume expired below functional residual capacity. We conclude that, in patients with SLT for ILD, the slope of the alveolar plateau obtained with the graft in the nondependent position reflects heterogeneity of ventilation distribution in this lung.
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PMID:Single-breath test in lateral decubitus reflects function of single lungs grafted for interstitial lung disease. 1799 91

Although closing volume is regarded as a clinical test for the early detection of peripheral airway closure, its grounds are not clear. There have been no simulation studies for phase IV in the single-breath nitrogen washout (SBNW) curve, even though several mathematical models for phase III have been proposed. We modeled the lung tissue deformation during slow expiration in which the tissue was regarded as a porous elastic body similar to a sponge. We assigned the maximum tissue density of lung parenchyma over which the lung tissue could not be contracted according to several experimental reports in literature. SBNW curves were then simulated by computing expired air volume and nitrogen concentration for respective acini in the lung model. The simulated SBNW curves well reproduced phase IV, cardiac oscillation, and its postural changes. We found that the higher lung compliance increased closing volume, but decreased residual volume. The smaller maximum tissue density generated larger closing volume and larger residual volume. It suggested that phase IV reflected the alveolar contractility, and the increase of closing volume in emphysema could be explained by an insufficient contraction of alveoli. We also found that the distribution of maximum tissue density affected the onset of Phase IV. A constant value of density generated a clear onset, but a wide distribution of it corresponding to peripheral airway closure obscured it. We suggest that the airway closure was not necessary for phase IV appearance in both normal and emphysematous lung.
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PMID:A novel interpretation of closing volume based on single-breath nitrogen washout curve simulation. 1807 Mar 74

Diffusion of hyperpolarized helium-3 in epoxy phantoms was experimentally studied by pulsed-gradient nuclear magnetic resonance (NMR). One phantom with a dichotomic branching structure densely filling a cubic volume was built using the Kitaoka algorithm to model a healthy human acinus. Two other phantoms, one with a different size and the other one with a partial destruction of the branched structure, were built to simulate changes occurring at the early stages of emphysema. Gas pressure and composition (mixture with nitrogen) were varied, thus exploring different diffusion regimes. Preliminary measurements in a cylindrical glass cell allowed us to calibrate the gradient intensity with 1% accuracy. Measurements of NMR signal attenuation due to gas diffusion were compared to a classical Gaussian model and to Monte Carlo simulations. In the slow diffusion regime, the Gaussian model was in reasonable agreement with experiments for low gradient intensity, but there was a significant systematic deviation at larger gradient intensity. An apparent diffusion coefficient Dapp was deduced, and in agreement with previous findings, a linear decrease of Dapp/D0 with D0(1/2) was observed, where D0 is the free diffusion coefficient. In the regime of intermediate diffusion, experimental data could be described by the Gaussian model for very small gradient intensities only. The corresponding Dapp/D0 values seemed to reach a constant value. Monte Carlo simulations were generally in fair agreement with the measurements in both regimes. Our results suggest that, for diffusion times typical of medical magnetic resonance imaging, an increase in alveolar size has more impact on signal attenuation than a partial destruction of the branched structure at equivalent surface-to-volume ratio.
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PMID:Gas diffusion in a pulmonary acinus model: experiments with hyperpolarized helium-3. 1853 24

A 28-year-old male was admitted to hospital with severe abdominal distension and subcutaneous emphysema after ingesting 15 ml liquid nitrogen to produce an impressive burp. A rupture of the stomach at the lesser curvature was sutured by laparotomy. Peroperative gastroscopy showed no signs of cold-induced lesions. Liquid nitrogen boils at -196 degrees C. When heated to body temperature, it instantly expands 700 times, in this case predictably leading to gastric rupture. Therefore, any oral intake of even small amounts of liquid nitrogen should be avoided.
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PMID:[Gastric rupture after ingestion of liquid nitrogen]. 1921 Sep 43

Indole and 3-methylindole (skatole) are odor pollutants in livestock waste, and skatole is a major component of boar taint. Skatole causes pulmonary edema and emphysema in ruminants and causes damage to lung Clara cells in animals and humans. A gas chromatographic method that originally used a nitrogen-phosphorus detector to increase sensitivity was modified resulting in an improved flame ionization detection response for indole and skatole of 236% and 207%, respectively. The improved method eliminates the large amount of indole decomposition in the injector. A 10 micro g mL(-1) spike of indole and skatole in water and swine fecal slurries resulted in recovery of 78.5% and 96% in water and 76.1% and 85.8% in fecal slurries, respectively. The effect of the addition of nitroethane and nitroethanol at 21.8 mM in swine fecal slurries was studied on the microbial production of indole and skatole. Nitroethane and nitroethanol decreased the production of skatole in swine fecal slurries at 24 h. The nitroethane effect on l-tryptophan-supplemented fecal slurries after 6 and 24 h incubation resulted in a decrease of 69.0% (P = 0.02) and 23.5% skatole production, respectively, and a decrease of 14.9% indole at 6 h, but an increase in indole production of 81.1% at 24 h.
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PMID:Effect of nitroethane and nitroethanol on the production of indole and 3-methylindole (skatole) from bacteria in swine feces by gas chromatography. 2018 70

Many epidemiological studies on the effects of nitrogen dioxide (NO(2)) on respiratory function may have included nitrous acid (HONO) exposures in their measures, because conventional NO(2) assays detect HONO as NO(2). A few epidemiological studies and human HONO inhalation experiments have associated HONO with decrements in lung functions. However, there have been few HONO exposure experiments in animals. This study aims to develop a HONO generation system for the animal exposure experiments, and to assess the association of HONO exposure with histopathologic alterations in the respiratory tract of guinea pigs. We exposed the guinea pigs to 3.6 ppm HONO with secondary products of 0.3 ppm NO(2) and 1.6 ppm nitric oxide (NO) for 4 weeks (24 h/day). We conducted histopathologic analyses and measured specific airway resistance (sRaw) from 7 h 40 min to 8 h 30 min after the end of HONO exposure. We found pulmonary emphysema-like alterations in the alveolar duct centriacinar regions, distortion of the centriacinar regions of alveolar ducts with extension of the bronchial epithelial cells and smooth muscle cells, and expansion of bronchial epithelial cells, in the HONO exposure. These histopathologic results suggest that a high concentration of HONO with some NO(2) and NO may associate with decrements in lung functions and some respiratory symptoms. Although the increased tendency of the sRaw value was observed in the HONO exposure group, no statistically significant difference was found between the sRaw values from the HONO exposure group and the filtered air group (p = 0.06, student's t-test).
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PMID:Effects of nitrous acid exposure on pulmonary tissues in guinea pigs. 2068 73

We report a case of a patient treated by retroperitoneoscopic partial nephrectomy who developed nitrogenous subcutaneous emphysema (SCE) as a complication. The use of a nitrogen gas-pressured fibrin tissue adhesive applied as a spray caused excessively increased pressure in the closed retroperitoneal space and resulted in widespread SCE with protracted clinical course. To the best of our knowledge, this is the first report of nitrogenous SCE associated with pneumoperitoneum. The clinical significance of nitrogenous SCE is emphasized, and the risks associated with the use of fibrin glue as a spray during laparoscopic surgery are discussed.
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PMID:Nitrogenous subcutaneous emphysema caused by spray application of fibrin glue during retroperitoneal laparoscopic surgery. 2142 2


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