Electron Paramagnetic Resonance Assessment of Brain Tissue Oxygen Tension in Anesthetized Rats

Hou, Huagang; Grinberg, Oleg Y.; Taie, Satoshi; Leichtweis, S.; Miyake, Minoru; Grinberg, Stalina; Xie, Haiyi; Csete, Marie; Swartz, Harold M.

doi:10.1213/01.ane.0000055648.41152.63

Cited by 48 publications

(32 citation statements)

References 23 publications

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“…At normal therapeutic concentrations IF has minimal effects on the respiratory system, and among different anesthetics tested it achieves the greatest stability of cardiovascular parameters of mice and the highest cerebral pO 2 in rats [26,28,30] . However, it has been shown that cerebral pO 2 in rats anesthetized with IF is still lower than in control unanesthetized restrained rats [30] , which proves that IF can also affect tissue oxygenation.…”

Section: Discussionmentioning

confidence: 96%

“…The effects of general anesthesia on blood pressure, cardiac function and cerebral blood flow have been intensively studied and are well documented [26][27][28] . It was shown that the anesthetic agents used in animal protocols can markedly influence the metabolism of O 2 , blood flow and pO 2 in muscle, brain and tumors [26,29] . However, studies have not been carried out to determine the effect of anesthetics on skin oxygenation.…”

Section: Discussionmentioning

confidence: 99%

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Influence of Different Anesthetics on Skin Oxygenation Studied by Electron Paramagnetic Resonance in vivo

Abramović

Šentjurc

Kristl

et al. 2006

Skin Pharmacol Physiol

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The effects of two general anesthetics on skin oxygenation in mice are evaluated by electron paramagnetic resonance oximetry. Up to now no data on the effects of different anesthetics on skin oxygenation could be found. In this study animals were anesthetized with ketamine/xylazine or isoflurane, and partial pressure of oxygen (pO₂) in the skin, heart rate and hemoglobin oxygen saturation were followed as a function of time and inhaled oxygen concentration. The skin pO₂ significantly increased continuously for about 60 min in mice anesthetized with isoflurane and remained constant after that. During ketamine/xylazine anesthesia, the pO₂ in the skin only slightly decreased. The skin pO₂ increased with higher inspired oxygen concentrations for both anesthetics groups. When breathing 21% oxygen, mice anesthetized with isoflurane had two-fold higher pO₂ in the skin compared to mice anesthetized with ketamine/xylazine. The heart rate was significantly lower in animals anesthetized with ketamine/xylazine, while hemoglobin saturation was almost the same in both groups at all inhaled oxygen concentrations. These results show that the type of anesthesia is an important parameter that needs to be considered in experiments where skin pO₂ is followed.

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Section: Discussionmentioning

confidence: 96%

Section: Discussionmentioning

confidence: 99%

Influence of Different Anesthetics on Skin Oxygenation Studied by Electron Paramagnetic Resonance in vivo

Abramović

Šentjurc

Kristl

et al. 2006

Skin Pharmacol Physiol

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show abstract

“…In several studies, isoflurane, compared with other anesthetic agents, maintained stable cerebral blood flow and high tissue oxygenation 86,87 and, thus, does not cause false interpretations of tissue hypoxia. Indeed, the decrease in blood pressure and cerebral perfusion caused by the related anesthetic desflurane has been associated with increased brain oxygenation, 88 possibly as a result of its vasodilator properties and lower cerebral metabolic rate.…”

Section: Hypoxia and Cerebralmentioning

confidence: 99%

CNS Hypoxia Is More Pronounced in Murine Cerebral than Noncerebral Malaria and Is Reversed by Erythropoietin

Hempel

Combes

Hunt

et al. 2011

The American Journal of Pathology

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Cerebral malaria (CM) is associated with high mortality and risk of sequelae, and development of adjunct therapies is hampered by limited knowledge of its pathogenesis. To assess the role of cerebral hypoxia, we used two experimental models of CM, Plasmodium berghei ANKA in CBA and C57BL/6 mice, and two models of malaria without neurologic signs, P. berghei K173 in CBA mice and P. berghei ANKA in BALB/c mice. Hypoxia was demonstrated in brain sections using intravenous pimonidazole and staining with hypoxia-inducible factor-1␣-specific antibody. Cytopathic hypoxia was studied using poly (ADP-ribose) polymerase-1 (PARP-1) gene knockout mice. The effect of erythropoietin, an oxygen-sensitive cytokine that mediates protection against CM, on cerebral hypoxia was studied in C57BL/6 mice. Numerous hypoxic foci of neurons and glial cells were observed in mice with CM. Substantially fewer and smaller foci were observed in mice without CM, and hypoxia seemed to be confined to neuronal cell somas. PARP-1-deficient mice were not protected against CM, which argues against a role for cytopathic hypoxia. Erythropoietin therapy reversed the development of CM and substantially reduced the degree of neural hypoxia. These findings demonstrate cerebral hypoxia in malaria, strongly associated with cerebral dysfunction and a possible target for adjunctive therapy.

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“…This feature permits the use of LiPc as an oximetry probe in brain. [168][169][170] The narrowness of the linewidth is also particularly suitable for multisite spectroscopy. One limitation of this material is the rapid saturation at low power.…”

Section: Particulate Paramagnetic Materialsmentioning

confidence: 99%

Assessment of tumor oxygenation by electron paramagnetic resonance: principles and applications

2004

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This review paper attempts to provide an overview of the principles and techniques that are often termed electron paramagnetic resonance (EPR) oximetry. The paper discusses the potential of such methods and illustrates they have been successfully applied to measure oxygen tension, an essential parameter of the tumor microenvironment. To help the reader understand the motivation for carrying out these measurements, the importance of tumor hypoxia is first discussed: the basic issues of why a tumor is hypoxic, why these hypoxic microenvironments promote processes driving malignant progression and why hypoxia dramatically influences the response of tumors to cytotoxic treatments will be explained. The different methods that have been used to estimate the oxygenation in tumors will be reviewed. To introduce the basics of EPR oximetry, the specificity of in vivo EPR will be discussed by comparing this technique with NMR and MRI. The different types of paramagnetic oxygen sensors will be presented, as well as the methods for recording the information (EPR spectroscopy, EPR imaging, dynamic nuclear polarization). Several applications of EPR for characterizing tumor oxygenation will be illustrated, with a special emphasis on pharmacological interventions that modulate the tumor microenvironment. Finally, the challenges for transposing the method into the clinic will also be discussed.

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Electron Paramagnetic Resonance Assessment of Brain Tissue Oxygen Tension in Anesthetized Rats

Cited by 48 publications

References 23 publications

Influence of Different Anesthetics on Skin Oxygenation Studied by Electron Paramagnetic Resonance in vivo

Influence of Different Anesthetics on Skin Oxygenation Studied by Electron Paramagnetic Resonance in vivo

CNS Hypoxia Is More Pronounced in Murine Cerebral than Noncerebral Malaria and Is Reversed by Erythropoietin

Assessment of tumor oxygenation by electron paramagnetic resonance: principles and applications

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