scholarly journals Noninvasive measure of microvascular nitric oxide function in humans using Very low frequency cutaneous laser Doppler flow spectra.

2007 ◽  
Vol 21 (6) ◽  
Author(s):  
Julian Mark Stewart ◽  
Indu Taneja ◽  
Marvin Scott Medow ◽  
Michael Goligorsky
Keyword(s):  
Nitric Oxide ◽  
Low Frequency ◽  
Laser Doppler ◽  
Laser Doppler Flow ◽  
Doppler Flow ◽  
Very Low Frequency

scholarly journals Noninvasive Measure of Microvascular Nitric Oxide Function in Humans Using Very Low-Frequency Cutaneous Laser Doppler Flow Spectra

2007 ◽  
Vol 14 (3) ◽  
pp. 169-180 ◽  
Author(s):  
Julian M. Stewart ◽  
Indu Taneja ◽  
Michael S. Goligorsky ◽  
Marvin S. Medow
Keyword(s):  
Nitric Oxide ◽  
Low Frequency ◽  
Laser Doppler ◽  
Laser Doppler Flow ◽  
Doppler Flow ◽  
Very Low Frequency

Synchronous Rhythmical Vasomotion in the Human Cutaneous Microvasculature during Nonpulsatile Cardiopulmonary Bypass

2002 ◽  
Vol 97 (5) ◽  
pp. 1110-1117 ◽  
Author(s):  
Mihai V. Podgoreanu ◽  
Robert G. Stout ◽  
Habib E. El-Moalem ◽  
David G. Silverman
Keyword(s):  
Cardiopulmonary Bypass ◽  
High Frequency ◽  
Spectral Power ◽  
Low Frequency ◽  
Approximate Entropy ◽  
Laser Doppler ◽  
Control Mechanisms ◽  
Laser Doppler Flow ◽  
Doppler Flow ◽  
Normalized Units

Background The origin, control mechanisms, and functional significance of oscillations in microvascular flow are incompletely understood. Although the traditional belief has been that only low-frequency oscillations (0.04-0.10 Hz) can originate at the microvascular level, recent evidence in healthy volunteers has suggested that high-frequency oscillations (> 0.10 Hz) also may have a microvascular origin (as opposed to being mechanically transmitted respiratory-induced variations in stroke volume). The current study determined if such oscillations would emerge in the absence of cardiac and respiratory activity during nonpulsatile cardiopulmonary bypass (NP-CPB). Methods Forehead and finger laser Doppler flow, arterial pressure, and core temperature were simultaneously recorded in eight patients during NP-CPB. Analyses included time- domain indices, frequency-domain indices (auto power spectral density), and a measure of regularity (approximate entropy) for standardized time segments. Results Nonpulsatile cardiopulmonary bypass was associated with the emergence of rhythmical oscillations in laser Doppler flow, with characteristic frequencies for the forehead (0.13 +/- 0.03 Hz) and finger (0.07 +/- 0.02 Hz). Forehead vasomotion became progressively synchronized, with a gain in high-frequency spectral power from 17.5 (minute 1) to 89.1 (minute 40) normalized units, and a decrease in approximate entropy from 1.2 (before NP-CPB) to less than 0.5 (minute 40). Conclusions The emergence of forehead microvascular oscillations at greater than 0.10 Hz (characteristic of parasympathetic frequency response), in the absence of cardiac and respiratory variability, demonstrates their peripheral origin and provides insights into parasympathetic vasoregulatory mechanisms. The progressive synchronization of forehead vasomotion during NP-CPB, suggestive of increased coupling among microvascular biologic oscillators, may represent a microcirculatory homeostatic response to systemic depulsation, with potential implications for end-organ perfusion.

Modification of cerebral laser-Doppler flow oscillations by halothane, PCO2, and nitric oxide synthase blockade

1995 ◽  
Vol 269 (1) ◽  
pp. H114-H120 ◽  
Author(s):  
A. G. Hudetz ◽  
J. J. Smith ◽  
J. G. Lee ◽  
Z. J. Bosnjak ◽  
J. P. Kampine
Keyword(s):  
Nitric Oxide ◽  
No Synthase ◽  
Laser Doppler ◽  
Oscillatory Activity ◽  
Sprague Dawley ◽  
Laser Doppler Flow ◽  
Doppler Flow ◽  
Sprague Dawley Rats ◽  
Flow Oscillations ◽  
Oxide Synthase

We investigated whether nitric oxide (NO) played a role in the generation of cerebrocortical flow oscillations and their modification by hypocapnia, hypercapnia, and halothane administration. Parietal cortical laser-Doppler flow (LDF) was monitored transcranially in anesthetized (barbiturate + 0-1.0% halothane), artificially ventilated, adult male Sprague-Dawley rats. Thirty minutes after infusion of N omega-nitro-L-arginine methyl ester (L-NAME, 20 mg/kg i.v.) mean arterial pressure (MAP) increased from 105 +/- 10 to 132 +/- 15 mmHg (P < 0.02), while mean LDF decreased from 159 +/- 36 to 135 +/- 30 perfusion units (PU, P < 0.05). Oscillations in LDF at a frequency of 6.3-7.8 cycles/min and amplitude of 10% were induced or augmented by L-NAME but not by D-NAME or indomethacin (2 mg/kg i.p.). L-arginine (200 mg/kg) abolished the oscillations post-L-NAME at constant MAP. Sodium nitroprusside infusion (10(-5) M, 5-50 microliters/min) reversed the L-NAME-induced increase in MAP and decrease in mean LDF but did not attenuate the flow oscillations. Hypocapnia post-L-NAME decreased LDF to 110 +/- 20 PU (P < 0.001) and augmented the flow oscillations (amplitude: 11-31%). Hypercapnia (5% CO2) or halothane (0.4-1.0%) suspended the oscillations in the presence of L-NAME. The results suggest that NO synthase activity inhibits cerebrocortical flow oscillations, and NO is not an obligatory mediator of the effects of halothane, hypocapnia, and hypercapnia on oscillatory activity.

The Role of Nitric Oxide in Cerebrocortical Laser Doppler Flow Response to Halothane in the Rat

1995 ◽  
Vol 7 (3) ◽  
pp. 187-195 ◽  
Author(s):  
Jeremy J. Smith ◽  
Antal G. Hudetz ◽  
Zeljko J. Bosnjak ◽  
John P. Kampine
Keyword(s):  
Nitric Oxide ◽  
Laser Doppler ◽  
Laser Doppler Flow ◽  
Doppler Flow ◽  
Flow Response

Laser Doppler Flow-Meter Assessment of Iontophoretically Applied Norepinephrine on Human Finger Skin Circulation

1986 ◽  
Vol 87 (5) ◽  
pp. 634-636 ◽  
Author(s):  
Lars Erik Lindblad ◽  
Lena Ekenvall ◽  
Klas Ancker ◽  
Håkan Rohman ◽  
P Åke Öberg
Keyword(s):  
Laser Doppler ◽  
Flow Meter ◽  
Laser Doppler Flow ◽  
Doppler Flow ◽  
Skin Circulation ◽  
Human Finger ◽  
Finger Skin
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