Regional cerebral blood flow and tissue oxygenation during hypocarbia in geese

1992 ◽  
Vol 263 (2) ◽  
pp. R221-R225 ◽  
Author(s):  
P. E. Bickler ◽  
D. Julian
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
High Altitude ◽  
Regional Cerebral Blood Flow ◽  
Gas Flow ◽  
Regional Cerebral Blood ◽  
Local Blood Flow ◽  
Tissue Po2 ◽  
O2 Delivery ◽  
Kinetics Of

Very low arterial CO2 tension (PaCO2) experienced by birds during high-altitude flight may result in cerebral vasoconstriction and reduced cerebral O2 delivery. To examine this possibility, we measured regional cerebral blood flow (CBF) and tissue PO2 in pentobarbital-anesthetized geese (Anser domesticus). Twenty-five-micrometer Teflon-coated platinum electrodes for H2-clearance measurements of local blood flow or tissue PO2 were implanted in the cerebral cortex in 11 geese. Tissue H2 and O2 were measured by voltage clamping the electrodes at +0.30 and -0.5 V, respectively. Washout kinetics of H2 gas administered via unidirectional lung ventilation was used to calculate local blood flow for those electrodes exhibiting one- or two-compartment washout kinetics of H2 (128 of 296 washouts in 31 electrodes). PaCO2 was controlled between 8 and 55 mmHg by altering pulmonary gas flow or by adjusting inspired PCO2. CBF decreased as PaCO2 fell from 50 to 20 mmHg but did not decrease further as PaCO2 was reduced below 20 mmHg. CBF was uniformly distributed in different regions of the cortex. Despite the plateau in CBF during severe hypocapnia, tissue PO2 continued to decline as PaCO2 fell below 20 mmHg. Severe alkalosis may limit cerebral O2 delivery in birds during high-altitude flight.

Effects of temperature and anoxia on regional cerebral blood flow in turtles

1992 ◽  
Vol 262 (3) ◽  
pp. R538-R541
Author(s):  
P. E. Bickler
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Regional Cerebral Blood Flow ◽  
Brain Regions ◽  
Platinum Electrodes ◽  
Regional Cerebral Blood ◽  
Blood Flows ◽  
Effects Of Temperature ◽  
Kinetics Of ◽  
Hydrogen Clearance

Regional cerebral blood flow (CBF) was measured in isoflurane-anesthetized turtles (Pseudemys scripta) by the hydrogen clearance method. Teflon-coated platinum electrodes (25 microns) were implanted in the olfactory bulbs, midcerebral cortex and cerebellum in eight adult turtles. The electrodes were voltage clamped at +0.30 V relative to a Ag-AgCl electrode implanted in the dorsal neck muscles. Washout kinetics of H2 gas administered via controlled ventilation was used to calculate local blood flow for electrodes exhibiting monoexponential washout kinetics of hydrogen (92 of 104 determinations). Data were obtained in animals with body temperatures of 15, 25, and 35 degrees C under normocapnic conditions during ventilation with 21% O2 and during ventilation with 100% N2. During normoxia, mean blood flows were 1.9 +/- 0.8, 5.0 +/- 1.9, and 6.1 +/- 1.3 (+/- SD) ml.100 g-1.min-1 at 15, 25, and 35 degrees C, respectively. There were no differences between CBF values in the different brain regions. During 1-3 h of anoxia, CBF was 3.0 +/- 2.1, 7.0 +/- 3.7, and 6.6 +/- 2.9 ml.100 g-1.min-1 at 15, 25, and 35 degrees C, respectively (normoxia-anoxia difference not statistically different). Hypercarbia (ventilation with 10-20% CO2 in air or N2), or the transition from anoxia to normoxia, increased CBF up to 80% at each of these temperatures. Maintenance of CBF during anoxia likely contributes to the anoxia tolerance of the turtle brain.

Regional cerebral blood flow in natives at high altitude: An arterial spin labeled MRI study

2018 ◽  
Vol 48 (3) ◽  
pp. 708-717 ◽  
Author(s):  
Xiaochuan Wang ◽  
Wenping Wei ◽  
Fengjuan Yuan ◽  
Shanhua Li ◽  
Jianzhong Lin ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
High Altitude ◽  
Regional Cerebral Blood Flow ◽  
Regional Cerebral Blood ◽  
Mri Study

Regional cerebral blood flow in schizophrenia while performing an attention task

2014 ◽  
Author(s):  
Scott Harcourt ◽  
Daniel G. Amen ◽  
Kristin C. Willeumier ◽  
Charles J. Golden
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Regional Cerebral Blood Flow ◽  
Regional Cerebral Blood ◽  
Attention Task

Vorläufige Ergebnisse von 99mTc-HMPAO-SPECT-Untersuchungen bei endogenen Psychosen

1989 ◽  
Vol 28 (03) ◽  
pp. 88-91
Author(s):  
J. Schröder ◽  
H. Henningsen ◽  
H. Sauer ◽  
P. Georgi ◽  
K.-R. Wilhelm
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Regional Cerebral Blood Flow ◽  
Regions Of Interest ◽  
Post Mortem ◽  
Regional Cerebral Blood ◽  
Hmpao Spect ◽  
Endogenous Psychoses ◽  
The Brain ◽  
99Mtc Hmpao

18 psychopharmacologically treated patients (7 schizophrenics, 5 schizoaffectives, 6 depressives) were studied using 99mTc-HMPAO-SPECT of the brain. The regional cerebral blood flow was measured in three transversal sections (infra-/supraventricular, ventricular) within 6 regions of interest (ROI) respectively (one frontal, one parietal and one occipital in each hemisphere). Corresponding ROIs of the same section in each hemisphere were compared. In the schizophrenics there was a significantly reduced perfusion in the left frontal region of the infraventricular and ventricular section (p < 0.02) compared with the data of the depressives. The schizoaffectives took an intermediate place. Since the patients were treated with psychopharmaca, the result must be interpreted cautiously. However, our findings seem to be in accordance with post-mortem-, CT- and PET-studies presented in the literature. Our results suggest that 99mTc-HMPAO-SPECT may be helpful in finding cerebral abnormalities in endogenous psychoses.

133Xe-DSPECT: Normalwerte von zerebraler Ruhedurchblutung und Reservekapazität

1987 ◽  
Vol 26 (05) ◽  
pp. 192-197 ◽  
Author(s):  
T. Kreisig ◽  
P. Schmiedek ◽  
G. Leinsinger ◽  
K. Einhäupl ◽  
E. Moser
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Cerebrovascular Disease ◽  
Correlation Coefficient ◽  
Regional Cerebral Blood Flow ◽  
Regression Line ◽  
Reserve Capacity ◽  
Regional Cerebral Blood ◽  
Quantitative Measurements ◽  
Before And After

Using the 133Xe-DSPECT technique, quantitative measurements of regional cerebral blood flow (rCBF) were performed before and after provocation with acetazolamide (Diamox) i. v. in 32 patients without evidence of brain disease (normals). In 6 cases, additional studies were carried out to establish the time of maximal rCBF increase which was found to be approximately 15 min p. i. 1 g of Diamox increases the rCBF from 58 ±8 at rest to 73±5 ml/100 g/min. A Diamox dose of 2 g (9 cases) causes no further rCBF increase. After plotting the rCBF before provocation (rCBFR) and the Diamox-induced rCBF increase (reserve capacity, Δ rCBF) the regression line was Δ rCBF = −0,6 x rCBFR +50 (correlation coefficient: r = −0,77). In normals with relatively low rCBF values at rest, Diamox increases the reserve capacity much more than in normals with high rCBF values before provocation. It can be expected that this concept of measuring rCBF at rest and the reserve capacity will increase the sensitivity of distinguishing patients with reversible cerebrovascular disease (even bilateral) from normals.

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