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  • 2000-2004
  • 1985-1989  (4)
  • 1915-1919
  • 1910-1914
  • Closing volume  (2)
  • Growth  (2)
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  • 2000-2004
  • 1985-1989  (4)
  • 1915-1919
  • 1910-1914
  • 1970-1974  (1)
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  • 1
    Electronic Resource
    Electronic Resource
    Single breath N2 washout in papain-induced pulmonary emphysema (1989)
    Springer
    Intensive care medicine 15 (1989), S. 308-313 
    Details
    ISSN: 1432-1238
    Keywords: Pulmonary emphysema ; Papain ; Single-breath test for oxygen ; Nitrogen washout ; Closing volume
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Single breath nitrogen washout tests were analyzed in dogs (n=8) with healthy lungs and after development of emphysema. The animals were in the supine position and studied during anaesthesia and mechanical ventilation (FiO2=0.4, FiN2=0.6). During controlled expiration with constant flow (VE=0.15 1/s) onset of phase IV of the alveolar plateau was related to airway closure of dependent lung regions (closing volume CV). In the control state, CV accounted for 6.2±1.5% VC, and closing capacity (CC) was lower than functional residual capacity (FRC). Likewise, gas exchange was normal in all animals (PaO2=24.7±3.32 kPa, PaCO2=5.18±0.53 kPa, PA-aO2=2.6±0.3 kPa). Panlobular emphysema (PLE) was induced by inhalation of papain (100 mg/kg). After three weeks development of PLE was documented by messurements of lung volumes (functional residual capacity (FRC), expired vital capacity (EVC), total lung capacity (TLC), residual volume (RV)), pulmonary mechanics (dynamic and static compliance (Cdyn, Cstat), mean airway resistance (Raw)), gas exchange (PaO2, PaCO2, PA-aO2), and by radiomorphological analysis. In the PLE-group, FRC and RV (p≤0.05), and Cstat (p≤0.01) were significantly elevated. CV increased to 16.2±2.7% VC (p≤0.01) and CC exceeded FRC by 80 ml, indicating that tidal volume breathing took place within the range of closing volume. Oxygenation was significantly impaired (PaO2=18.6±3.72 kPa, PA-aO2-6.5±1.1 kPa, p≤0.05), but not CO2-elimination. Pathological analysis by radiomorphological means showed dissiminate parenchymal lesions compatible with emphysema of grade II severity located predominantly in subpleural areas. In dogs with papain-induced PLE, premature closure of dependent airways is enhanced, which is due to structural changes and a loss of elastic recoil in the lungs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00263866
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    High-frequency jet ventilation during oleic-acid induced pulmonary oedema (1989)
    Springer
    Intensive care medicine 15 (1989), S. 105-110 
    Details
    ISSN: 1432-1238
    Keywords: Oleic acid-induced pulmonary oedema ; High-frequency jet ventilation ; Continuous positive pressure ventilation ; Gas exchange ; Closing volume
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In oleci acid-induced pulmonary oedema (OAPO) sequential intrapulmonary fluid accumulation occurs leading to different expiratory flow pattern in dependent lung regions. The potential effects on efficacy of high-frequency jet ventilation (HFJV, f=3 Hz, I: E=0.43, FiO2=0.4) were studied and compared with continous positive pressure ventilation (CPPV, f=12–18/min, I:E=0.5, TV=12 ml/kg, PEEP=0.5 kPa, FiO2=0.4) in a dog model of OAPO. In the control state (lung-healthy dogs), 15 min afteroleic acid lung injury (interstitial oedema, period I) and 60 min after onset of OAPO (alveolar oedema, period II), gas exchange, lung volumes, compliance, resistance and haemodynamics were measured. The course of lung oedema was determined indirectly by means of washout curvesof helium (foreign gas bolus-test, FGB) and nitrogen (single breath-test for oxygen, SBO2). During control, there were no significant differences between the HFJV-group (n=7) and the CPPV-group(n=6) by virtue of gas exchange, lung volumes and haemodynamics. During period I, PaO2 decreased signiicantly both with HFJV (p〈0.01) and CPPV (p〈0.05), being lower in the HFJV-group (p〈0.05). PaCO2, pulmonary and haemodynamic parameters were unchanged. Onset of phase IV of the alveolar plateau (closing volume CV) occurred significantly earlier (p〈0.05) in all animals. Impaired ventilation of dependent lung regions, increased maldistribution of intrapulmonary gas and VA/Q-mismatching may be the underlying mechanisms for lower efficacy of HFJV during interstitial lung oedema. In period II, pulmonary and cardiocirculatory parameters had changed significantly in both groups. CV had decreased, indicating a biphasic behavior of washout curves, which is due to changes of regional FRC, resistance and compliance after onset of alveolar flooding. Oxygenation was significantly more impaired in the HFJV-group (p〈0.05). CPPV is superior to HFJV in maintaining sufficient gas exchange both during interstitial and alveolar oedema in dogs with oleic acid-induced lung injury.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00295986
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Performance of two Picea abies (L.) Karst. stands at different stages of decline (1988)
    Springer
    Oecologia 75 (1988), S. 25-37 
    Details
    ISSN: 1432-1939
    Keywords: Forest decline ; Carbohydrates ; Picea abies ; Growth ; Leaf area index
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary This is the first in a series of papers on the growth, photosynthetic rate, water and nutrient relations, root distribution and mycorrhizal frequency of two Norway spruce forests at different stages of decline. One of the stands was composed of green trees only while the other included trees ranging in appearance from full green crowns to thin crowns with yellow needles. In this paper we compare the growth and carbohydrate relations of the two stands and examine relationships among growth variables in ten plots. The declining stand produced 65 percent of the wood per ground area compared with the stand in which all trees were green because its foliage produced less wood at any level of leaf area index. The difference in foliage efficiency between the sites could not be explained by differeneces in climate, competition or stand structure. The declining stand appeared to have lower carbon gain as indicated by a smaller increase in reserve carbohydrates before bud break, and weaker sinks for carbohydrates as indicated by less use of the stored carbohydrates than the healthy stand. Thus, growth reduction was probably related to factors which affect both photosynthesis and, even more, the sinks for carbohydrate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00378810
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Performance of two Picea abies (L.) Karst. stands at different stages of decline (1988)
    Springer
    Oecologia 77 (1988), S. 163-173 
    Details
    ISSN: 1432-1939
    Keywords: Forest decline ; Spruce (Picea abies) ; Nutrients ; Growth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A declining, closed-canopy Picea abies (L.) Karst. stand produced as much crown biomass as a healthy stand, although some trees were chlorotic due to magnesium deficiency. The production of wood per unit of leaf area in both stands was related to the foliar magnesium concentration. Although leaf area index and climate were similar at both sites, stemwood production was 35% lower in the declining than in the healthy stand. Nutritional disharmony, rather than a deficiency in a single element, was identified as the mechanism for reduced tree vigor. The role of nutrient stress in forest decline was detected by partitioning the season into three periods reflecting different phenological stages: a canopy growth period in spring, a stem growth period in summer, and a recharge period during the non-growing season. Needle growth was associated with nitrogen supply. Most of the magnesium supply required to meet the demand for foliage growth was retranslocated from mature needles. Magnesium retranslocation was related to concentration of nitrogen and magnesium in those needles before bud break. Retranslocation from mature needles during the phase of canopy production resulted in chlorosis in initially green needles if the magnesium concentration before bud break was low. Nitrogen concentration in 0-year-old needles generally remained constant with increasing supply, indicating that foliage growth was restricted by the supply of nitrogen. In contrast, magnesium concentration generally increased with supply, indicating that magnesium supply for needle growth was sufficient. Much of the magnesium required for wood production was taken up from the soil because stored magnesium was largely used for canopy growth. Uptake at the declining site was probably limited because of restricted root expansion and lower soil magnesium compared to the healthy site. For this reason only wood growth was reduced at the declining site. Because the recharge of magnesium during the non-growing period is dependent on uptake from the soil, it was more limited at the declining that at the healthy stand. However, as nitrogen uptake from the atmosphere may account for an appreciable proportion of the total uptake, and as its supply in the soil at both sites was similar, an unbalanced recharge of nitrogen and magnesium may have occurred at the declining site. If mature needles are unable to recharge with magnesium in proportion to the uptake of nitrogen, chlorosis is likely to occur during the next canopy growth period.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00379182
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    Paper (German National Licenses)
    Fulltext
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