scholarly journals Influence of the Endothelial Glycocalyx on Cerebral Blood Flow in Mice

2000 ◽  
Vol 20 (11) ◽  
pp. 1571-1578 ◽  
Author(s):  
J. Vogel ◽  
M. Sperandio ◽  
A.R. Pries ◽  
O. Linderkamp ◽  
P. Gaehtgens ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Laser Doppler Flowmetry ◽  
Laser Doppler ◽  
Endothelial Glycocalyx ◽  
Doppler Flowmetry ◽  
Laser Doppler Flow ◽  
Doppler Flow ◽  
Cerebral Capillaries ◽  
Saline Treatment

The endothelial surface layer (glycocalyx) of cerebral capillaries may increase resistance to blood flow. This hypothesis was investigated in mice by intravenous administration of heparinase (2500 IU/kg body weight in saline), which cleaves proteoglycan junctions of the glycocalyx. Morphology was investigated by transmission electron microscopy. Cerebral perfusion velocity was recorded before and during heparinase or saline treatment using laser–Doppler flowmetry. In addition, cerebral blood flow (CBF) was measured 10 minutes after heparinase or saline treatment using the iodo[14C]antipyrine method. Laser–Doppler flowmetry and CBF measurements were performed during normocapnia and severe hypercapnia (Pco2: 120 mm Hg). After heparinase, morphology showed a reduced thickness of the glycocalyx in cortical microvessels by 43% ( P < 0.05) compared with saline-treated controls. Under normocapnic conditions, a 15% ( P < 0.05) transient increase of cerebral flow velocity occurred 2.5 to 5 minutes after heparinase injection. Laser–Doppler flow and CBF returned to control values ten minutes after the injection. However, during severe hypercapnia, heparinase treatment resulted in a persisting increase in laser–Doppler flow (6%, P < 0.05) and CBF (30%, P < 0.05). These observations indicate the existence of a flow resistance in cerebral capillaries exerted by the glycocalyx. The transient nature of the CBF increase during normocapnia may be explained by a vascular compensation that is exhausted during severe hypercapnia.

scholarly journals Correlation of rheoencephalography and laser Doppler flow: a rat study

2019 ◽  
Vol 7 (1) ◽  
pp. 55-58 ◽  
Author(s):  
Michael Bodo ◽  
Ryan Sheppard ◽  
Aaron Hall ◽  
Martin Baruch ◽  
Melissa Laird ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Laser Doppler Flowmetry ◽  
Characteristic Curve ◽  
Laser Doppler ◽  
Doppler Flowmetry ◽  
Laser Doppler Flow ◽  
Doppler Flow ◽  
Cerebral Blood Flow Autoregulation ◽  
Rat Study

Abstract Measuring brain electrical impedance (rheoencephalography) is a potential technique for noninvasive, continuous neuro-monitoring of cerebral blood flow autoregulation in humans. In the present rat study, we compared changes in cerebral blood flow autoregulation during CO2 inhalation measured by rheoencephalography to changes measured by laser Doppler flowmetry, an invasive continuous monitoring modality. Our hypothesis was that both modalities would reflect cerebral blood flow autoregulation. Male Sprague-Dawley rats (n=28; 28 control and 82 CO2 challenges) were measured under anesthesia. The surgical preparation involved implantation of intracerebral REG electrodes and an LDF probe into the brain. Analog waveforms were stored in a computer. CO2 inhalation caused transient, simultaneous increases in the signals of both laser Doppler flow (171.99 ± 46.68 %) and rheoencephalography (329.88 ± 175.50%). These results showed a correlation between the two measured modalities; the area under the receiver operating characteristic curve was 0.8394. The similar results obtained by measurements made with laser Doppler flowmetry and rheoencephalography indicate that rheo-encephalography, like laser Doppler flowmetry, reflects cerebral blood flow autoregulation. Rheoencephalography therefore shows potential for use as a continuous neuro-monitoring technique.

Evaluation of laser-Doppler flowmetry as a measure of tissue blood flow

1986 ◽  
Vol 61 (2) ◽  
pp. 666-672 ◽  
Author(s):  
G. J. Smits ◽  
R. J. Roman ◽  
J. H. Lombard
Keyword(s):  
Blood Flow ◽  
Laser Doppler Flowmetry ◽  
Electromagnetic Flowmeter ◽  
Laser Doppler ◽  
Tissue Blood Flow ◽  
Organ Blood Flow ◽  
Doppler Flowmetry ◽  
Laser Doppler Flow ◽  
Doppler Flow

In this study the technique of laser-Doppler flowmetry was evaluated for the measurement of tissue blood flow by comparing laser-Doppler flow (LDF) signal in the renal cortex, gracilis muscle, and cremaster muscle of anesthetized rats to whole-organ blood flow measured with an electromagnetic flowmeter or radioactive microspheres. In vitro, LDF signal was closely correlated (r = 0.99) to changes in erythrocyte velocity generated with a rotating wheel. Although individual LDF readings varied in situ, mean LDF signal calculated from multiple readings on the tissue surface were significantly correlated (r = 0.74–0.95) with tissue blood flows measured at various perfusion pressures. However, significant differences in the slope of the LDF signal vs. blood flow relationship were observed in different tissues and with different methods of measurement in the same tissue. This study indicates that mean laser-Doppler flow signal provides a good estimate of tissue blood flow, provided a sufficient number of points is scanned. However, there appears to be no universal calibration factor for the method.

The Characteristics of Laser-Doppler Flowmetry for the Measurement of Regional Cerebral Blood Flow

Neurosurgery ◽  
1995 ◽  
Vol 36 (2) ◽  
pp. 358???364 ◽  
Author(s):  
Osamu Fukuda ◽  
Shunro Endo ◽  
Naoya Kuwayama ◽  
Jun Harada ◽  
Akira Takaku
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Laser Doppler Flowmetry ◽  
Regional Cerebral Blood Flow ◽  
Laser Doppler ◽  
Regional Cerebral Blood ◽  
Doppler Flowmetry

Effect of nimodipine on the autoregulation of cerebral blood flow studied by laser-Doppler flowmetry

1993 ◽  
Vol 625 (2) ◽  
pp. 301-306 ◽  
Author(s):  
Geneviève Florence ◽  
Gilles Bonvento ◽  
Pascal Roucher ◽  
Robert Charbonne ◽  
Jacques Seylaz
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Laser Doppler Flowmetry ◽  
Laser Doppler ◽  
Doppler Flowmetry
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