scholarly journals Role of blood-oxygen transport in thermal tolerance of the cuttlefish, Sepia officinalis

2007 ◽  
Vol 47 (4) ◽  
pp. 645-655 ◽  
Author(s):  
F. Melzner ◽  
F. C. Mark ◽  
H. O. Portner
1991 ◽  
Vol 260 (4) ◽  
pp. R798-R803
Author(s):  
M. Riera ◽  
J. F. Fuster ◽  
L. Palacios

The effects of two different degrees of experimentally induced anemia and the consequent high percentage of circulating immature erythrocytes on oxygen affinity (pH 7.5 and 41 degrees C), erythrocyte organic phosphates, and Hb fractions have been studied in quail. Blood reticulocytes reached percentages of 24 and 69-87% in the first and second experiments, respectively. Variations in the phosphate levels found during the anemic process were related to the amount of circulating reticulocytes. The erythrocyte [ATP] (brackets indicate concentration) and [ATP]/[Hb] molar ratio increased with the release of reticulocytes and returned to control levels as they matured. The erythrocyte [inositol pentakisphosphate (InsP5)] decreased significantly when circulating reticulocytes showed their highest values, whereas there was hardly any effect on the [InsP5]/[Hb] molar ratio, which changed only slightly. Hb-O2 affinity also exhibited no statistical changes associated with acute anemia. These latter findings indicate that InsP5, at physiological concentrations, is the primary modulator of quail Hb function; the observed rise in [ATP] has no additional influence on Hb-O2 affinity. It is suggested that InsP5 tends to maintain the blood oxygen affinity in both mature erythrocytes and reticulocytes. The main compensatory response at blood level is a rapid bulk reticulocyte release from medulla.


Mathematics ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 910
Author(s):  
Andrey Kovtanyuk ◽  
Alexander Chebotarev ◽  
Varvara Turova ◽  
Irina Sidorenko ◽  
Renée Lampe

An inverse problem for a system of equations modeling oxygen transport in the brain is studied. The problem consists of finding the right-hand side of the equation for the blood oxygen transport, which is a linear combination of given functionals describing the average oxygen concentration in the neighborhoods of the ends of arterioles and venules. The overdetermination condition is determined by the values of these functionals evaluated on the solution. The unique solvability of the problem is proven without any smallness assumptions on the model parameters.


Hepatology ◽  
1997 ◽  
Vol 26 (2) ◽  
pp. 336-342 ◽  
Author(s):  
T Huang ◽  
T Nishida ◽  
W Kamike ◽  
H Kosaka ◽  
A Seiyama ◽  
...  

2011 ◽  
Vol 215 (1) ◽  
pp. 93-102 ◽  
Author(s):  
B. Speers-Roesch ◽  
J. G. Richards ◽  
C. J. Brauner ◽  
A. P. Farrell ◽  
A. J. R. Hickey ◽  
...  

1980 ◽  
Vol 20 (1) ◽  
pp. 173-185 ◽  
Author(s):  
F HARVEY POUGH

2020 ◽  
Vol 17 (165) ◽  
pp. 20190732 ◽  
Author(s):  
John Tarbell ◽  
Marwa Mahmoud ◽  
Andrea Corti ◽  
Luis Cardoso ◽  
Colin Caro

Atherosclerosis and vascular disease of larger arteries are often associated with hypoxia within the layers of the vascular wall. In this review, we begin with a brief overview of the molecular changes in vascular cells associated with hypoxia and then emphasize the transport mechanisms that bring oxygen to cells within the vascular wall. We focus on fluid mechanical factors that control oxygen transport from lumenal blood flow to the intima and inner media layers of the artery, and solid mechanical factors that influence oxygen transport to the adventitia and outer media via the wall's microvascular system—the vasa vasorum (VV). Many cardiovascular risk factors are associated with VV compression that reduces VV perfusion and oxygenation. Dysfunctional VV neovascularization in response to hypoxia contributes to plaque inflammation and growth. Disturbed blood flow in vascular bifurcations and curvatures leads to reduced oxygen transport from blood to the inner layers of the wall and contributes to the development of atherosclerotic plaques in these regions. Recent studies have shown that hypoxia-inducible factor-1α (HIF-1α), a critical transcription factor associated with hypoxia, is also activated in disturbed flow by a mechanism that is independent of hypoxia. A final section of the review emphasizes hypoxia in vascular stenting that is used to enlarge vessels occluded by plaques. Stenting can compress the VV leading to hypoxia and associated intimal hyperplasia. To enhance oxygen transport during stenting, new stent designs with helical centrelines have been developed to increase blood phase oxygen transport rates and reduce intimal hyperplasia. Further study of the mechanisms controlling hypoxia in the artery wall may contribute to the development of therapeutic strategies for vascular diseases.


2016 ◽  
Vol 3 (4) ◽  
pp. 367-373 ◽  
Author(s):  
J. Freitas ◽  
J. Braz-Nogueira ◽  
J. Nogueira da Costa ◽  
J. Martins e Silva

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