Dynamics of tumor oxygenation and red blood cell flux in response to inspiratory hyperoxia combined with different levels of inspiratory hypercapnia

2002 ◽  
Vol 62 (1) ◽  
pp. 77-85 ◽  
Author(s):  
Oliver Thews ◽  
Debra K. Kelleher ◽  
Peter Vaupel
2004 ◽  
Vol 56 (4) ◽  
pp. 670-670 ◽  
Author(s):  
B J Blessinger ◽  
R Figueroa-Colon ◽  
D A Diersen-Schade ◽  
D R Hoffman ◽  
C L Harris ◽  
...  

2021 ◽  
Vol 118 (25) ◽  
pp. e2025236118
Author(s):  
Romain Enjalbert ◽  
David Hardman ◽  
Timm Krüger ◽  
Miguel O. Bernabeu

The tumor microenvironment is abnormal and associated with tumor tissue hypoxia, immunosuppression, and poor response to treatment. One important abnormality present in tumors is vessel compression. Vessel decompression has been shown to increase survival rates in animal models via enhanced and more homogeneous oxygenation. However, our knowledge of the biophysical mechanisms linking tumor decompression to improved tumor oxygenation is limited. In this study, we propose a computational model to investigate the impact of vessel compression on red blood cell (RBC) dynamics in tumor vascular networks. Our results demonstrate that vessel compression can alter RBC partitioning at bifurcations in a hematocrit-dependent and flow rate–independent manner. We identify RBC focusing due to cross-streamline migration as the mechanism responsible and characterize the spatiotemporal recovery dynamics controlling downstream partitioning. Based on this knowledge, we formulate a reduced-order model that will help future research to elucidate how these effects propagate at a whole vascular network level. These findings contribute to the mechanistic understanding of hemodilution in tumor vascular networks and oxygen homogenization following pharmacological solid tumor decompression.


2009 ◽  
Vol 27 (15_suppl) ◽  
pp. e20719-e20719
Author(s):  
J. W. Nortier ◽  
A. Ogilvie

e20719 Background: To determine in patients with cancer related anaemia (Hb<11,3 g/d) starting with their chemotherapy the efficacy and safety of up-front red blood cell transfusion and subsequently maintenance epoetin-alpha (Epo) administration. The study target was the range of low-normal Hb levels of 11,3 to 12,9 g/dL aiming at improving tumor oxygenation. Methods: A multicenter, open label, single-arm phase II study. All eligible patients with metastatic solid cancers received around their first or second chemotherapy cycle a transfusion of 1–3 units of erythrocytes depending on their Hb level. This was followed by Epo subcutaneously weekly at an initial dose of 40,000 IU during the chemotherapy period. Epo was only administered when the Hb level was below the lower margin of the target Hb range. All patients started with pre-emptive oral iron suppletion. Primary objectives were: correction of anemia to the Hb level target range and safety. Secondary objectives were: Quality of Life, Length of Treatment Duration and Time to Treatment Failure. Safety included: blood pressure, thrombo-embolic events, adverse events and serious adverse event. Results: 18 Patients enrolled in this study from March 30, 2006 to November 11, 2008. An intention-to-treatment analysis was performed for the primary objectives in 16 patients (8 with breast-, 4 with colorectal-, 1 with ovarian- and 1 with pancreatic cancer) and reported here. Patients were during a median of 12 weeks (range 1 to 32 weeks) on study. Median Hb increased from 10,2 g/dL to 11,2 g/dL after transfusion and stayed at that level during the first 19 weeks of Epo administration; Hb levels were between 10,0 and 11,5 g/dL. In the following period until the final 32nd studyweek, Hb levels increased slightly, ranging from 10,3 to 11,8 g/dL. Two patients remained during the study in the Hb level target range. The safety of Epo was good. Grade 3/4 adverse events and serious adverse events that occurred were found to be all chemotherapy or progressive disease related. Conclusions: Although this up-front treatment increased Hb to stable levels during chemotherapy, the target Hb levels were not reached in most patients. This was presumably related to the lesser than projected yield of the red blood cell transfusion. [Table: see text]


1995 ◽  
Vol 34 (3) ◽  
pp. 379-384 ◽  
Author(s):  
Debra K. Kelleher ◽  
Ulrike Matthiensen ◽  
Oliver Thews ◽  
Peter Vaupel

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