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Duane J Funk M Ruth Graham Linda G Girling James A Thliveris Bruce M McManus Elizabeth KY Walker Edward S Rector Craig Hillier J Elliott Scott W Alan C Mutch 《Respiratory research》2004,5(1):22
BackgroundBiologically variable ventilation (return of physiological variability in rate and tidal volume using a computer-controller) was compared to control mode ventilation with and without a recruitment manoeuvre – 40 cm H2O for 40 sec performed hourly; in a porcine oleic acid acute lung injury model.MethodsWe compared gas exchange, respiratory mechanics, and measured bronchoalveolar fluid for inflammatory cytokines, cell counts and surfactant function. Lung injury was scored by light microscopy. Pigs received mechanical ventilation (FIO2 = 0.3; PEEP 5 cm H2O) in control mode until PaO2 decreased to 60 mm Hg with oleic acid infusion (PaO2/FIO2 <200 mm Hg). Additional PEEP to 10 cm H2O was added after injury. Animals were randomized to one of the 3 modes of ventilation and followed for 5 hr after injury.ResultsPaO2 and respiratory system compliance was significantly greater with biologically variable ventilation compared to the other 2 groups. Mean and mean peak airway pressures were also lower. There were no differences in cell counts in bronchoalveolar fluid by flow cytometry, or interleukin-8 and -10 levels between groups. Lung injury scoring revealed no difference between groups in the regions examined. No differences in surfactant function were seen between groups by capillary surfactometry.ConclusionsIn this porcine model of acute lung injury, various indices to measure injury or inflammation did not differ between the 3 approaches to ventilation. However, when using a low tidal volume strategy with moderate levels of PEEP, sustained improvements in arterial oxygen tension and respiratory system compliance were only seen with BVV when compared to CMV or CMV with a recruitment manoeuvre. 相似文献
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CO2-Enrichment and photosynthetic photon flux affect the growth of in vitro-cultured apple plantlets
Ru Yu Li Hosakatte Niranjana Murthy Seon Kyu Kim Kee Yeoup Paek 《Journal of Plant Biology》2001,44(2):87-91
Micro-cuttings (shoots with two small leaves) of cultivar M9 apple were cultured in-vitro for 40 d under CO2-enriched and non-enriched (i.e., ambient air) conditions, and at a PPF of 40 or 100 μmol m-2 s-1 Afterward, shoot length, number of leaves, leaf area, chlorophyll content, shoot and root fresh weights, and % survival were
recorded. Those plant-lets grown under CO2- and PPF-enriched treatments were healthy and vigorous, and showed higher values for their growth parameters. In contrast,
those grown without supplemental CO2 or PPF often showed hyperhydricity. We also demonstrated that CO2 enrichment and a relatively high PPF during in-vitro culture promoted normal photosynthesis and growth after ex-vitro transplantation. 相似文献