Simultaneous Tissue PO2, Nitric Oxide, and Laser Doppler Blood Flow Measurements during Neuronal Activation of Optic Nerve

Author(s):  
Donald G. Buerk ◽  
Dmitriy N. Atochin ◽  
Charles E. Riva
1987 ◽  
Vol 253 (4) ◽  
pp. G573-G581 ◽  
Author(s):  
G. R. DiResta ◽  
J. W. Kiel ◽  
G. L. Riedel ◽  
P. Kaplan ◽  
A. P. Shepherd

To perform two independent regional blood flow measurements in tissue volumes of similar dimensions, we designed a hybrid blood flow probe capable of measuring regional perfusion by both laser-Doppler velocimetry (LDV) and H2 clearance. The probe consisted of two fiber-optic light guides to conduct light between the surface of tissue of interest and a laser-Doppler blood flowmeter. Also contained within the probe were a platinum 25-microns H2-sensing electrode and a 125-microns H2-generating electrode. The probe can thus be used to measure local perfusion with H2 clearance. The H2 can either be inhaled or can be generated electrochemically at the locus of interest. Evaluation of the probe in the canine gastric mucosa indicated 1) that the relationship between mucosal flow measurements made simultaneously with H2 clearance and LDV was highly significant and linear and 2) that H2 clearance could potentially be used to calibrate the laser-Doppler blood flowmeter in absolute units. The methods of constructing the flow probes are discussed in detail.


1987 ◽  
Vol 18 (3) ◽  
pp. 212-217 ◽  
Author(s):  
Marcus Walkinshaw ◽  
Alan Holloway ◽  
Ann Bulkley ◽  
Loren H. Engrav

1994 ◽  
Vol 267 (6) ◽  
pp. G1035-G1040 ◽  
Author(s):  
A. P. Houdijk ◽  
P. A. Van Leeuwen ◽  
M. A. Boermeester ◽  
T. Van Lambalgen ◽  
T. Teerlink ◽  
...  

The hemodynamic consequences of glutamine (Gln)-enriched nutrition have not been investigated. This study investigates the effects of a Gln-enriched enteral diet on organ blood flows and systemic hemodynamics. Male Fischer 344 rats (n = 24) were randomized to a group that received a 12.5% (wt/wt) Gln-enriched enteral diet or an isonitrogenous isocaloric control diet for 14 days. Blood flow measurements were performed at day 16 using 46Sc-labeled microspheres. In the Gln-enriched group, higher organ blood flows were measured in the stomach (51%), the pancreas (35%), small intestine (32%), and colon (55%), compared with controls. No differences were found in systemic hemodynamic parameters between the control and Gln-supplemented groups. A possible role for nitric oxide in this splanchnic vasodilation was investigated. Daily urinary nitrate excretion was measured during the study but showed no significant differences between the control and Gln-fed animals. No differences were found in plasma levels of the vasodilating hormone glucagon between the groups. These results show that a Gln-enriched enteral diet increased splanchnic blood flow, which was not mediated by pancreatic glucagon or increased nitric oxide production as determined by urinary nitrate excretion.


2002 ◽  
Vol 111 (11) ◽  
pp. 998-1001 ◽  
Author(s):  
Tsutomu Nakashima ◽  
Taku Hattori ◽  
Eisuke Sato ◽  
Michihiko Sone ◽  
Mitsuo Tominaga

We measured cochlear blood flow in 12 patients who received cochlear implants, using a laser-Doppler probe with an outer diameter of 0.8 mm. The subjects had congenital deafness, idiopathic progressive sensorineural hearing loss, Waardenburg's syndrome, narrow internal auditory canal, or sudden deafness. Putting the probe tip to the site of drilling for cochlear implantation, we measured blood flow before, during, and after the cochlear bony wall was opened. The laser-Doppler output was confirmed even after the tip of the probe was inserted into the perilymphatic space in all cases. Our results revealed that blood flow was maintained in all cochleas, although there was a probability of reduction in blood flow volume. We conclude that laser-Doppler flowmetry is both relatively safe and useful for measuring blood flow in the ears during cochlear implantation procedures.


1990 ◽  
Vol 85 (4) ◽  
pp. 581-586 ◽  
Author(s):  
Jay Goldberg ◽  
Richard S. Sepka ◽  
Barbara P. Perona ◽  
William C. Pederson ◽  
Bruce Klitzman

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