The Experts below are selected from a list of 12183 Experts worldwide ranked by ideXlab platform
Walter H Dzik - One of the best experts on this subject based on the ideXlab platform.
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the air we breathe three vital Respiratory Gases and the red blood cell oxygen nitric oxide and carbon dioxide
Transfusion, 2011Co-Authors: Walter H DzikAbstract:Three vital Respiratory Gases-oxygen (O(2)), nitric oxide (NO), and carbon dioxide (CO(2))-intersect at the level of the human red blood cell (RBC). In addition to hemoglobin (Hb)'s central role in O(2) transport, interaction of Hb with the Band 3 metabolon balances RBC energy flow. 2,3-Diphosphoglycerate enhances O(2) transport across the placenta and plays an important role in regulating RBC plasticity. NO is a key mediator of hypoxic vasodilation, but the precise role of RBC Hb remains controversial. In addition to established theories that depend on RBC uptake, delivery, and discharge of NO or its metabolites, an alternative hypothesis based on RBC permeability is suggested. NO depletion by free Hb may account for several clinical features seen during intravascular hemolysis or during deliberate infusion of Hb solutions used as RBC substitutes. CO(2) released by tissues triggers oxygen release through a series of well-coordinated reactions centered on the Band 3 metabolon. While RBC carbonic anhydrase and the Band 3 anion exchanger are central to this process, there is surprisingly little research on the kinetics of CO(2) clearance by transfusion. The three RBC Gases are directly related to the three principal Gases of Earth's atmosphere. Human fossil fuel consumption dumps 90 million metric tons of carbon into the atmosphere annually. Increasing CO(2) levels are linked to global warming, melting Arctic ice, rising sea levels, and climate instability. Just as individual cells depend on balance of the three vital Gases, so too will their balance determine survival of life on Earth.
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three Respiratory Gases and the red cell oxygen nitrogen and carbon dioxide
Pathology, 2011Co-Authors: Walter H DzikAbstract:Three vital Gases—oxygen, nitrogen, and carbon dioxide—intersect at the level of the human red blood cell. The delivery of oxygen to all tissues by red cells is essential to human life. Evolution has created a complex molecule, haemoglobin, designed for efficient uptake and off-loading of oxygen. Iron rests at the centre of the haem moiety and is critical for oxygen exchange. Although studied for over a century, some details of oxygen transport by the red cell remain uncertain. Recent research has focusedon the interactionofhaemoglobin with a complex of cell-membrane proteins centred on band 3. In addition, there is renewed interest in the question of whether or not stored red cells deliver oxygen to tissues as well as fresh red cells. Nitric oxide (NO) physiology is directly related to oxygen delivery by the red cell. NO serves a local vasodilator to increase blood flow to hypoxic tissue beds. NO binds strongly to haemoglobin which serves as an NO sink. Under normal conditions, plasma NO synthesised by endothelial cells is not consumed by red cell haemoglobin due to a diffusion blockade across the red cell membrane that results from membrane structures not fully identified. Under conditions of red cell lysis, free haemoglobin scavenges NO reducing local vasodilation. Scavenging of NO is now recognised as an important component of the physiological response to chronic haemolysis and is very likely to play an important role in the renal lesion of acute haemolysis. The interactions of CO 2 with the red cell have drawn far less research attention. Plasma CO 2 released by tissues serves as an essential trigger for oxygen release by haemoglobin via the Hal-dane effect. CO 2 transport depends on conversion of CO 2 to bicarbonate via red cell carbonic anhydrase in conjunction with chloride exchange across the red cell membrane. There is very little research on the effect of blood storage on CO 2 excretion although this aspect of Respiratory physiology is every bit as important as oxygen delivery. The three RBC Gases are also the three principal Gases of the Earth’s atmosphere. While CO 2 is the least abundant of the three by far, it is also likely to be the most critical to the future survival of life on Earth because small further increases in the concentration of CO 2 will result in continued climate change and large increases will be deadly. Thus, the management of three vital Gases by the collection of red cells found within us has broad similarities to the collective management of our atmosphere. Just as the survival of individual tissue cells depends upon proper balance of these three Respiratory Gases, so too will their proper balance be the key to survival of life on Earth.
Svetlana Mintova - One of the best experts on this subject based on the ideXlab platform.
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ruthenium tris 2 2 bipyridyl complex encapsulated in nanosized faujasite zeolite as intracellular localization tracer
Journal of Colloid and Interface Science, 2021Co-Authors: Sarah Komaty, Hayriye Özçelik, Moussa Zaarour, Aurélie Ferré, Samuel Valable, Svetlana MintovaAbstract:Abstract Designing zeolites for medical applications is a challenging task that requires introducing new functionalities without altering the intrinsic properties such as morphology, crystallinity, colloidal stability, surface charge, and porosity. Herein, we present the encapsulation of luminescent ruthenium-tris(2,2′-bipyridyl) complex in faujasite (FAU) zeolite nanocrystals (Ru(bpy)3-FAU) and their use as an intracellular localization tracer. Upon exciting the Ru(bpy)3-FAU zeolite at 450 nm, the sample gives rise to an orange-red emission at 628 nm, thus permitting its use for cellular imaging and localization of the zeolite nanoparticles. The nanosized Ru(bpy)3-FAU zeolite is characterized in terms of size, charge, crystallinity, morphology, porosity, thermal stability, and sorption capacity. The potential toxicity of Ru(bpy)3-FAU on U251-MG glioblastoma cells was evaluated. A safe concentration (50-100 µg/ml) for the Ru(bpy)3-FAU zeolite is identified. The luminescent properties of the ruthenium complex confined in the zeolite nanocrystals allow their localization in the U251-MG cells with a main accumulation in the cytoplasm. The Ru(bpy)3-FAU nanosized zeolite is a potential candidate for biological applications for being stable, safe, capable of loading Respiratory Gases, and easily probed in the cells owing to its luminescent properties.
John S Terblanche - One of the best experts on this subject based on the ideXlab platform.
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Respiratory dynamics of discontinuous gas exchange in the tracheal system of the desert locust schistocerca gregaria
The Journal of Experimental Biology, 2012Co-Authors: Berlize Groenewald, Stefan K Hetz, Steven L Chown, John S TerblancheAbstract:Gas exchange dynamics in insects is of fundamental importance to understanding evolved variation in breathing patterns, such as discontinuous gas exchange cycles (DGCs). Most insects do not rely solely on diffusion for the exchange of Respiratory Gases but may also make use of Respiratory movements (active ventilation) to supplement gas exchange at rest. However, their temporal dynamics have not been widely investigated. Here, intratracheal pressure, V(CO2) and body movements of the desert locust Schistocerca gregaria were measured simultaneously during the DGC and revealed several important aspects of gas exchange dynamics. First, S. gregaria employs two different ventilatory strategies, one involving dorso-ventral contractions and the other longitudinal telescoping movements. Second, although a true spiracular closed (C)-phase of the DGC could be identified by means of subatmospheric intratracheal pressure recordings, some CO(2) continued to be released. Third, strong pumping actions do not necessarily lead to CO(2) release and could be used to ensure mixing of Gases in the closed tracheal system, or enhance water vapour reabsorption into the haemolymph from fluid-filled tracheole tips by increasing the hydrostatic pressure or forcing fluid into the haemocoel. Finally, this work showed that the C-phase of the DGC can occur at any pressure. These results provide further insights into the mechanistic basis of insect gas exchange.
Sarah Komaty - One of the best experts on this subject based on the ideXlab platform.
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ruthenium tris 2 2 bipyridyl complex encapsulated in nanosized faujasite zeolite as intracellular localization tracer
Journal of Colloid and Interface Science, 2021Co-Authors: Sarah Komaty, Hayriye Özçelik, Moussa Zaarour, Aurélie Ferré, Samuel Valable, Svetlana MintovaAbstract:Abstract Designing zeolites for medical applications is a challenging task that requires introducing new functionalities without altering the intrinsic properties such as morphology, crystallinity, colloidal stability, surface charge, and porosity. Herein, we present the encapsulation of luminescent ruthenium-tris(2,2′-bipyridyl) complex in faujasite (FAU) zeolite nanocrystals (Ru(bpy)3-FAU) and their use as an intracellular localization tracer. Upon exciting the Ru(bpy)3-FAU zeolite at 450 nm, the sample gives rise to an orange-red emission at 628 nm, thus permitting its use for cellular imaging and localization of the zeolite nanoparticles. The nanosized Ru(bpy)3-FAU zeolite is characterized in terms of size, charge, crystallinity, morphology, porosity, thermal stability, and sorption capacity. The potential toxicity of Ru(bpy)3-FAU on U251-MG glioblastoma cells was evaluated. A safe concentration (50-100 µg/ml) for the Ru(bpy)3-FAU zeolite is identified. The luminescent properties of the ruthenium complex confined in the zeolite nanocrystals allow their localization in the U251-MG cells with a main accumulation in the cytoplasm. The Ru(bpy)3-FAU nanosized zeolite is a potential candidate for biological applications for being stable, safe, capable of loading Respiratory Gases, and easily probed in the cells owing to its luminescent properties.
Berlize Groenewald - One of the best experts on this subject based on the ideXlab platform.
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Respiratory dynamics of discontinuous gas exchange in the tracheal system of the desert locust schistocerca gregaria
The Journal of Experimental Biology, 2012Co-Authors: Berlize Groenewald, Stefan K Hetz, Steven L Chown, John S TerblancheAbstract:Gas exchange dynamics in insects is of fundamental importance to understanding evolved variation in breathing patterns, such as discontinuous gas exchange cycles (DGCs). Most insects do not rely solely on diffusion for the exchange of Respiratory Gases but may also make use of Respiratory movements (active ventilation) to supplement gas exchange at rest. However, their temporal dynamics have not been widely investigated. Here, intratracheal pressure, V(CO2) and body movements of the desert locust Schistocerca gregaria were measured simultaneously during the DGC and revealed several important aspects of gas exchange dynamics. First, S. gregaria employs two different ventilatory strategies, one involving dorso-ventral contractions and the other longitudinal telescoping movements. Second, although a true spiracular closed (C)-phase of the DGC could be identified by means of subatmospheric intratracheal pressure recordings, some CO(2) continued to be released. Third, strong pumping actions do not necessarily lead to CO(2) release and could be used to ensure mixing of Gases in the closed tracheal system, or enhance water vapour reabsorption into the haemolymph from fluid-filled tracheole tips by increasing the hydrostatic pressure or forcing fluid into the haemocoel. Finally, this work showed that the C-phase of the DGC can occur at any pressure. These results provide further insights into the mechanistic basis of insect gas exchange.