The Experts below are selected from a list of 13272 Experts worldwide ranked by ideXlab platform
Johan Petersson - One of the best experts on this subject based on the ideXlab platform.
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the influence of gravity on regional Lung Blood Flow in humans spect in the upright and head down posture
Journal of Applied Physiology, 2017Co-Authors: Alejandro Sanchezcrespo, Johan Petersson, Sten G E Lindahl, Margareta MureAbstract:Using a dual-isotope quantitative SPECT method, we demonstrated that although a shift in posture redistributes Blood Flow in the direction of gravity, the results are also consistent with Lung stru...
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regional Lung Blood Flow and ventilation in upright humans studied with quantitative spect
Respiratory Physiology & Neurobiology, 2009Co-Authors: Johan Petersson, Malin Rohdin, Alejandro Sanchezcrespo, Sven Nyren, Hans Jacobsson, Stig A Larsson, Sten G E LindahlAbstract:We used quantitative Single Photon Emission Computed Tomography (SPECT) to study the effect of the upright posture on regional Lung Blood Flow and ventilation. Nine (upright) plus seven (prone and supine) healthy volunteers were studied awake, breathing spontaneously. Regional Blood Flow and ventilation were marked in sitting upright, supine and prone postures using (113m)In-labeled macroaggregates and inhaled Technegas ((99m)Tc); both remain fixed in the Lung after administration. All images were obtained while supine. In comparison with horizontal postures, both Blood Flow and ventilation were greater in caudal regions when upright. The redistribution was greater for Blood Flow than for ventilation, resulting in decreasing ventilation-to-perfusion ratios down the Lung when upright. We conclude that gravity redistributes regional Blood Flow and ventilation in the upright posture, while the influence is much less in the supine and prone postures.
Sten G E Lindahl - One of the best experts on this subject based on the ideXlab platform.
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the influence of gravity on regional Lung Blood Flow in humans spect in the upright and head down posture
Journal of Applied Physiology, 2017Co-Authors: Alejandro Sanchezcrespo, Johan Petersson, Sten G E Lindahl, Margareta MureAbstract:Using a dual-isotope quantitative SPECT method, we demonstrated that although a shift in posture redistributes Blood Flow in the direction of gravity, the results are also consistent with Lung stru...
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regional Lung Blood Flow and ventilation in upright humans studied with quantitative spect
Respiratory Physiology & Neurobiology, 2009Co-Authors: Johan Petersson, Malin Rohdin, Alejandro Sanchezcrespo, Sven Nyren, Hans Jacobsson, Stig A Larsson, Sten G E LindahlAbstract:We used quantitative Single Photon Emission Computed Tomography (SPECT) to study the effect of the upright posture on regional Lung Blood Flow and ventilation. Nine (upright) plus seven (prone and supine) healthy volunteers were studied awake, breathing spontaneously. Regional Blood Flow and ventilation were marked in sitting upright, supine and prone postures using (113m)In-labeled macroaggregates and inhaled Technegas ((99m)Tc); both remain fixed in the Lung after administration. All images were obtained while supine. In comparison with horizontal postures, both Blood Flow and ventilation were greater in caudal regions when upright. The redistribution was greater for Blood Flow than for ventilation, resulting in decreasing ventilation-to-perfusion ratios down the Lung when upright. We conclude that gravity redistributes regional Blood Flow and ventilation in the upright posture, while the influence is much less in the supine and prone postures.
Alejandro Sanchezcrespo - One of the best experts on this subject based on the ideXlab platform.
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the influence of gravity on regional Lung Blood Flow in humans spect in the upright and head down posture
Journal of Applied Physiology, 2017Co-Authors: Alejandro Sanchezcrespo, Johan Petersson, Sten G E Lindahl, Margareta MureAbstract:Using a dual-isotope quantitative SPECT method, we demonstrated that although a shift in posture redistributes Blood Flow in the direction of gravity, the results are also consistent with Lung stru...
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regional Lung Blood Flow and ventilation in upright humans studied with quantitative spect
Respiratory Physiology & Neurobiology, 2009Co-Authors: Johan Petersson, Malin Rohdin, Alejandro Sanchezcrespo, Sven Nyren, Hans Jacobsson, Stig A Larsson, Sten G E LindahlAbstract:We used quantitative Single Photon Emission Computed Tomography (SPECT) to study the effect of the upright posture on regional Lung Blood Flow and ventilation. Nine (upright) plus seven (prone and supine) healthy volunteers were studied awake, breathing spontaneously. Regional Blood Flow and ventilation were marked in sitting upright, supine and prone postures using (113m)In-labeled macroaggregates and inhaled Technegas ((99m)Tc); both remain fixed in the Lung after administration. All images were obtained while supine. In comparison with horizontal postures, both Blood Flow and ventilation were greater in caudal regions when upright. The redistribution was greater for Blood Flow than for ventilation, resulting in decreasing ventilation-to-perfusion ratios down the Lung when upright. We conclude that gravity redistributes regional Blood Flow and ventilation in the upright posture, while the influence is much less in the supine and prone postures.
Goran Hedenstierna - One of the best experts on this subject based on the ideXlab platform.
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no redistribution of Lung Blood Flow by inhaled nitric oxide in endotoxemic piglets pretreated with an endothelin receptor antagonist
Journal of Applied Physiology, 2015Co-Authors: Sebastien Trachsel, Kristina Hambraeusjonzon, Maria Bergquist, Cecile Martijn, Luni Chen, Goran HedenstiernaAbstract:Inhaled nitric oxide (INO) improves ventilation-perfusion matching and alleviates pulmonary hypertension in patients with acute respiratory distress syndrome. However, outcome has not yet been shown to improve, and nonresponse is common. A better understanding of the mechanisms by which INO acts may guide in improving treatment with INO in patients with severe respiratory failure. We hypothesized that INO may act not only by vasodilation in ventilated Lung regions, but also by causing vasoconstriction via endothelin (ET-1) in atelectatic, nonventilated Lung regions. This was studied in 30 anesthetized, mechanically ventilated piglets. The fall in oxygenation and rise in pulmonary artery pressure during a sepsislike condition (infusion of endotoxin) were blunted by INO 40 ppm. Endotoxin infusion increased serum ET-1, and INO almost doubled the ratio between mRNA expression of endothelin receptor A (mediating vasoconstriction) and B (mediating vasodilation and clearance of ET-1) (ET-A/ET-B) in atelectatic Lung regions. INO caused a shift in Blood Flow away from atelectatic Lung regions in the endotoxemic piglets, but not during ET receptor antagonism. We conclude that INO in short-term experiments, in addition to causing selective pulmonary vasodilation in ventilated Lung regions, increases the ET-A/ET-B mRNA expression ratio in Lung tissue. This might augment the vasoconstriction in atelectatic Lung regions, enhancing the redistribution of pulmonary Blood Flow to ventilated Lung regions which are reached by INO. Such vasoconstriction may be an important additional factor explaining the effect of INO.
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individual Lung Blood Flow during unilateral hypoxia effects of inhaled nitric oxide
European Respiratory Journal, 1998Co-Authors: Kristina Hambraeusjonzon, L. Bindslev, Claes Frostell, Goran HedenstiernaAbstract:We hypothesized that the diversion of Blood away from a hypoxic Lung to the opposite oxygenated Lung can be enhanced by inhaling nitric oxide (NO) into the oxygenated Lung. We measured individual Lung Blood Flow when 50 ppm NO was selectively inhaled to: a hyperoxic Lung during contralateral hypoxia; a normoxic Lung during bilateral normoxia; and a hyperoxic Lung during bilateral hyperoxia. Twenty two patients with healthy Lungs were studied during intravenous anaesthesia. The Lungs were separately and synchronously ventilated. The relative perfusion of each Lung was assessed by the inert gas elimination technique. Unilateral hypoxic (inspiratory oxygen fraction (FI,O2) 0.05) ventilation during contralateral hyperoxia reduced the perfusion of the hypoxic Lung from a mean (SD) of 47 (9)% of cardiac output (Q'), to 30 (7)% (p<0.001) of Q'. NO inhalation to the hyperoxic Lung increased its Blood Flow from 70 (7)% to 75 (6)% (p<0.05) of Q', and reduced the Blood Flow to the hypoxic Lung to 25 (6)% (p<0.05). Unilateral NO inhalation during bilateral normoxia or hyperoxia had no effect on pulmonary Blood Flow distribution. Nitric oxide inhalation to a hyperoxic Lung increases the perfusion to this Lung by redistribution of Blood Flow if the opposite Lung is hypoxic.
Kristina Hambraeusjonzon - One of the best experts on this subject based on the ideXlab platform.
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no redistribution of Lung Blood Flow by inhaled nitric oxide in endotoxemic piglets pretreated with an endothelin receptor antagonist
Journal of Applied Physiology, 2015Co-Authors: Sebastien Trachsel, Kristina Hambraeusjonzon, Maria Bergquist, Cecile Martijn, Luni Chen, Goran HedenstiernaAbstract:Inhaled nitric oxide (INO) improves ventilation-perfusion matching and alleviates pulmonary hypertension in patients with acute respiratory distress syndrome. However, outcome has not yet been shown to improve, and nonresponse is common. A better understanding of the mechanisms by which INO acts may guide in improving treatment with INO in patients with severe respiratory failure. We hypothesized that INO may act not only by vasodilation in ventilated Lung regions, but also by causing vasoconstriction via endothelin (ET-1) in atelectatic, nonventilated Lung regions. This was studied in 30 anesthetized, mechanically ventilated piglets. The fall in oxygenation and rise in pulmonary artery pressure during a sepsislike condition (infusion of endotoxin) were blunted by INO 40 ppm. Endotoxin infusion increased serum ET-1, and INO almost doubled the ratio between mRNA expression of endothelin receptor A (mediating vasoconstriction) and B (mediating vasodilation and clearance of ET-1) (ET-A/ET-B) in atelectatic Lung regions. INO caused a shift in Blood Flow away from atelectatic Lung regions in the endotoxemic piglets, but not during ET receptor antagonism. We conclude that INO in short-term experiments, in addition to causing selective pulmonary vasodilation in ventilated Lung regions, increases the ET-A/ET-B mRNA expression ratio in Lung tissue. This might augment the vasoconstriction in atelectatic Lung regions, enhancing the redistribution of pulmonary Blood Flow to ventilated Lung regions which are reached by INO. Such vasoconstriction may be an important additional factor explaining the effect of INO.
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individual Lung Blood Flow during unilateral hypoxia effects of inhaled nitric oxide
European Respiratory Journal, 1998Co-Authors: Kristina Hambraeusjonzon, L. Bindslev, Claes Frostell, Goran HedenstiernaAbstract:We hypothesized that the diversion of Blood away from a hypoxic Lung to the opposite oxygenated Lung can be enhanced by inhaling nitric oxide (NO) into the oxygenated Lung. We measured individual Lung Blood Flow when 50 ppm NO was selectively inhaled to: a hyperoxic Lung during contralateral hypoxia; a normoxic Lung during bilateral normoxia; and a hyperoxic Lung during bilateral hyperoxia. Twenty two patients with healthy Lungs were studied during intravenous anaesthesia. The Lungs were separately and synchronously ventilated. The relative perfusion of each Lung was assessed by the inert gas elimination technique. Unilateral hypoxic (inspiratory oxygen fraction (FI,O2) 0.05) ventilation during contralateral hyperoxia reduced the perfusion of the hypoxic Lung from a mean (SD) of 47 (9)% of cardiac output (Q'), to 30 (7)% (p<0.001) of Q'. NO inhalation to the hyperoxic Lung increased its Blood Flow from 70 (7)% to 75 (6)% (p<0.05) of Q', and reduced the Blood Flow to the hypoxic Lung to 25 (6)% (p<0.05). Unilateral NO inhalation during bilateral normoxia or hyperoxia had no effect on pulmonary Blood Flow distribution. Nitric oxide inhalation to a hyperoxic Lung increases the perfusion to this Lung by redistribution of Blood Flow if the opposite Lung is hypoxic.
