Oxygen Metabolism and Microcirculation of the Brain in Various Conditions: Experimental Investigations

1987 ◽  
pp. 35-43
Author(s):  
M. R. Gaab ◽  
B. Poch ◽  
V. Heller
Keyword(s):  
Oxygen Metabolism ◽  
Experimental Investigations ◽  
The Brain

scholarly journals 15O Radioactivity Clearance is Faster after Intracarotid Bolus Injection of 15O-Labeled Oxyhemoglobin than after 15O-Water Injection

2003 ◽  
Vol 23 (7) ◽  
pp. 838-844 ◽  
Author(s):  
Chie Seki ◽  
Jeff Kershaw ◽  
Paule-Joanne Toussaint ◽  
Kenichi Kashikura ◽  
Tetsuya Matsuura ◽  
...  
Keyword(s):  
Brain Tissue ◽  
Bolus Injection ◽  
Water Injection ◽  
Oxygen Metabolism ◽  
Blood Stream ◽  
Time Range ◽  
Cerebral Oxygen ◽  
Cerebral Oxygen Metabolism ◽  
Finite Period ◽  
The Brain

The authors tested the hypothesis that the oxygen content of brain tissue is negligible by injecting an intracarotid bolus of 15O-labeled tracer into rats. Under the hypothesis, the clearance rates of 15O radioactivity from the brain after injections of both 15O-labeled water (H215O) and 15O-labeled oxyhemoglobin (HbO15O) should be identical. However, the logarithmic slope of the 15O radioactivity curve after HbO15O injection (0.494 ± 0.071 min-1) was steeper than that after H215O injection (0.406 ± 0.038 min−1) ( P<0.001, n = 13), where the time range used in the comparison was between 60 and 120 seconds after the injection. A possible interpretation of this result is that nonmetabolized O15O may dwell in the brain tissue for a finite period of time before it is eventually metabolized or returned to the blood stream unaltered. These findings contradict assumptions made by models currently used to measure cerebral oxygen metabolism.

Cybernetic times: Norbert Wiener, John Stroud, and the ‘brain clock’ hypothesis

2020 ◽  
Vol 33 (1) ◽  
pp. 80-108
Author(s):  
Henning Schmidgen
Keyword(s):  
Historical Context ◽  
Second World War ◽  
Experimental Investigations ◽  
World War ◽  
Norbert Wiener ◽  
Temporal Structures ◽  
Clock Hypothesis ◽  
The 19Th Century ◽  
Second World ◽  
The Brain

In 1955, Norbert Wiener suggested a sociological model according to which all forms of culture ultimately depended on the temporal coordination of human activities, in particular their synchronization. The basis for Wiener’s model was provided by his insights into the temporal structures of cerebral processes. This article reconstructs the historical context of Wiener’s ‘brain clock’ hypothesis, largely via his dialogues with John W. Stroud and other scholars working at the intersection of neurophysiology, experimental psychology, and electrical engineering. Since the 19th century, physiologists and psychologists have been conducting experimental investigations into the relation between time and the brain. Using innovative instruments and technologies, Stroud rehearsed these experiments, in part without paying any attention at all to the experimental traditions involved. Against this background, this article argues that the novelty of Wiener’s model relies largely on his productive rephrasing of physiological and psychological findings that had been established long before the Second World War.

scholarly journals PET studies of changes in cerebral blood flow and oxygen metabolism after unilateral microembolization of the brain in anesthetized dogs.

Stroke ◽  
1987 ◽  
Vol 18 (1) ◽  
pp. 128-137 ◽  
Author(s):  
J Weyne ◽  
G De Ley ◽  
G Demeester ◽  
C Vandecasteele ◽  
F L Vermeulen ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Oxygen Metabolism ◽  
Anesthetized Dogs ◽  
The Brain

Generalized decrease in brain glucose metabolism during fasting in humans studied by PET

1989 ◽  
Vol 256 (6) ◽  
pp. E805-E810 ◽  
Author(s):  
C. Redies ◽  
L. J. Hoffer ◽  
C. Beil ◽  
E. B. Marliss ◽  
A. C. Evans ◽  
...  
Keyword(s):  
Blood Flow ◽  
Blood Volume ◽  
Ketone Bodies ◽  
Oxygen Metabolism ◽  
Whole Body ◽  
Transfer Coefficients ◽  
Oxygen Utilization ◽  
Whole Brain ◽  
Brain Glucose ◽  
The Brain

In prolonged fasting, the brain derives a large portion of its oxidative energy from the ketone bodies, beta-hydroxybutyrate and acetoacetate, thereby reducing whole body glucose consumption. Energy substrate utilization differs regionally in the brain of fasting rat, but comparable information has hitherto been unavailable in humans. We used positron emission tomography (PET) to study regional brain glucose and oxygen metabolism, blood flow, and blood volume in four obese subjects before and after a 3-wk total fast. Whole brain glucose utilization fell to 54% of control (postabsorptive) values (P less than 0.002). The whole brain rate constant for glucose tracer phosphorylation fell to 51% of control values (P less than 0.002). Both parameters decreased uniformly throughout the brain. The 2-fluoro-2-deoxy-D-glucose lumped constant decreased from a control value of 0.57 to 0.43 (P less than 0.01). Regional blood-brain barrier transfer coefficients for glucose tracer, regional oxygen utilization, blood flow, and blood volume were unchanged.

scholarly journals Impaired response of cerebral oxygen metabolism to visual stimulation in Huntington’s disease

2020 ◽  
pp. 0271678X2094928
Author(s):  
Peter Klinkmueller ◽  
Martin Kronenbuerger ◽  
Xinyuan Miao ◽  
Jee Bang ◽  
Kia E Ultz ◽  
...  
Keyword(s):  
Huntington's Disease ◽  
Huntington’S Disease ◽  
Cerebral Blood Volume ◽  
Visual Stimulation ◽  
Occipital Cortex ◽  
Oxygen Metabolism ◽  
Dynamic Responses ◽  
Functional Impairments ◽  
Triplet Repeat Expansion ◽  
The Brain

Huntington’s disease (HD) is a neurodegenerative disease caused by a CAG triplet repeat expansion in the Huntingtin gene. Metabolic and microvascular abnormalities in the brain may contribute to early physiological changes that subserve the functional impairments in HD. This study is intended to investigate potential abnormality in dynamic changes in cerebral blood volume (CBV) and cerebral blood flow (CBF), and cerebral metabolic rate of oxygen (CMRO2) in the brain in response to functional stimulation in premanifest and early manifest HD patients. A recently developed 3-D-TRiple-acquisition-after-Inversion-Preparation magnetic resonance imaging (MRI) approach was used to measure dynamic responses in CBV, CBF, and CMRO2 during visual stimulation in one single MRI scan. Experiments were conducted in 23 HD patients and 16 healthy controls. Decreased occipital cortex CMRO2 responses were observed in premanifest and early manifest HD patients compared to controls ( P < 0.001), correlating with the CAG-Age Product scores in these patients ( R2 = 0.4, P = 0.001). The results suggest the potential value of this reduced CMRO2 response during visual stimulation as a biomarker for HD and may illuminate the role of metabolic alterations in the pathophysiology of HD.

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