scholarly journals Pharmacological MRI of the choroid and retina: Blood flow and BOLD responses during nitroprusside infusion

2011 ◽  
Vol 68 (4) ◽  
pp. 1273-1278 ◽  
Author(s):  
Yen-Yu I. Shih ◽  
Guang Li ◽  
Eric R. Muir ◽  
Bryan H. De La Garza ◽  
Jeffrey W. Kiel ◽  
...  
Keyword(s):  
Blood Flow ◽  
Bold Responses ◽  
Pharmacological Mri ◽  
Nitroprusside Infusion

scholarly journals Cerebral blood flow and BOLD responses to a memory encoding task: A comparison between healthy young and elderly adults

NeuroImage ◽  
2007 ◽  
Vol 37 (2) ◽  
pp. 430-439 ◽  
Author(s):  
Khaled Restom ◽  
Katherine J. Bangen ◽  
Mark W. Bondi ◽  
Joanna E. Perthen ◽  
Thomas T. Liu
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Memory Encoding ◽  
Elderly Adults ◽  
Bold Responses

Cerebral Blood Flow Does Not Change Following Sodium Nitroprusside Infusion During Hypothermic Cardiopulmonary Bypass

1989 ◽  
Vol 68 (2) ◽  
pp. 122-126 ◽  
Author(s):  
Anne T. Rogers ◽  
Donald S. Prough ◽  
David A. Stump ◽  
Glenn P. Gravlee ◽  
Kevin C. Angert ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Cardiopulmonary Bypass ◽  
Sodium Nitroprusside ◽  
Hypothermic Cardiopulmonary Bypass ◽  
Nitroprusside Infusion

Cardiovascular and flux relationships in canine ileum

1984 ◽  
Vol 247 (4) ◽  
pp. G357-G365
Author(s):  
D. Mailman
Keyword(s):  
Blood Flow ◽  
Sodium Nitroprusside ◽  
Capillary Pressure ◽  
Infusion Rate ◽  
Mesenteric Artery ◽  
Arterial Occlusion ◽  
Venous Occlusion ◽  
Anesthetized Dogs ◽  
Nitroprusside Infusion

Blood flow and pressure in denerved ileum of anesthetized dogs were altered by occlusion of the mesenteric artery or vein or by infusion of intra-arterial sodium nitroprusside (0.015-1.5 mg/min). Unidirectional Na and H2O fluxes were measured and absorptive site blood flow was estimated from the clearance of tritiated H2O. Net Na and H2O absorptions were reduced by mesenteric venous or arterial occlusion. Net secretion occurred with mesenteric venous occlusion. Nitroprusside reduced net absorption only at an infusion rate of 0.15 mg/min. The absorptive Na and H2O fluxes were reduced by both mesenteric venous or arterial occlusion, with venous occlusion being more effective. Nitroprusside reduced the absorptive Na flux at an infusion rate of 0.15 mg/min but not the absorptive H2O flux. The secretory flux of Na was increased by mesenteric venous occlusion but reduced by arterial occlusion and not changed by nitroprusside infusion. The secretory H2O flux was decreased by moderate degrees of mesenteric venous occlusion but was unchanged at greater levels. Arterial occlusion decreased secretory H2O fluxes. Nitroprossude infusion increased secretory H2O fluxes at an infusion rate of 0.015 mg/min. The absorptive and secretory Na and H2O fluxes were significantly correlated with absorptive site blood flow plus estimated capillary pressure. Absorptive site blood flow was primarily responsible for changes in absorptive fluxes and estimated capillary pressure for changes in secretory fluxes. Absorptive site blood flow affected the secretory and absorptive fluxes of H2O more equally than the Na fluxes.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Cerebral blood flow predicts multiple demand network activity and fluid intelligence across the lifespan

2021 ◽  
Author(s):  
SHUYI WU ◽  
LORRAINE K. TYLER ◽  
Richard N Henson ◽  
James Rowe ◽  
Kamen A Tsvetanov ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Cognitive Function ◽  
Old Age ◽  
Blood Oxygenation ◽  
Network Activity ◽  
Bold Response ◽  
Age Related ◽  
Bold Responses ◽  
Fluid Reasoning

The preservation of cognitive function into old age is a public health priority. Cerebral hypoperfusion is a hallmark of dementia but its impact on maintaining cognitive ability across the lifespan is less clear. We investigated the relationship between baseline cerebral blood flow (CBF) and blood oxygenation level-dependent (BOLD) response during a fluid reasoning task in a population-based adult lifespan cohort (N=227, age 18-88 years). As age differences in baseline CBF could lead to non-neuronal contributions to the BOLD signal, we introduced commonality analysis to neuroimaging, in order to dissociate performance-related CBF effects from the physiological confounding effects of CBF on the BOLD response. Accounting for CBF, we confirmed that performance- and age-related differences in BOLD responses in the multiple-demand network (MDN) implicated in fluid reasoning. Differences in baseline CBF across the lifespan explained not only performance-related BOLD responses, but also performance-independent BOLD responses. Our results suggest that baseline CBF is important for maintaining cognitive function, while its non-neuronal contributions to BOLD signals reflect an age-related confound. Maintaining perfusion into old age may serve to support brain function with behavioural advantage, regulating brain health.

scholarly journals Task-Evoked BOLD Responses Are Normal in Areas of Diaschisis After Stroke

2008 ◽  
Vol 23 (1) ◽  
pp. 52-57 ◽  
Author(s):  
Damien A. Fair ◽  
Abraham Z. Snyder ◽  
Lisa Tabor Connor ◽  
Binyam Nardos ◽  
Maurizio Corbetta
Keyword(s):  
Blood Flow ◽  
Block Design ◽  
Inferior Frontal Gyrus ◽  
Blood Oxygen Level Dependent ◽  
Bold Signal ◽  
Blood Oxygen Level ◽  
Positron Emission ◽  
Fmri Study ◽  
Bold Responses ◽  
Word Stem Completion

Objective. Cerebral infarction can cause diaschisis, a reduction of blood flow and metabolism in areas of the cortex distant from the site of the lesion. Although the functional magnetic resonance imaging (fMRI) blood oxygen level dependent (BOLD) signal is increasingly used to examine the neural correlates of recovery in stroke, its reliability in areas of diaschisis is uncertain. Design. The effect of chronic diaschisis as measured by resting positron emission tomography on task-evoked BOLD responses during word-stem completion in a block design fMRI study was examined in 3 patients, 6 months after a single left hemisphere stroke involving the inferior frontal gyrus and operculum. Results. The BOLD responses were minimally affected in areas of chronic diaschisis. Conclusions. Within the confines of this study, the mechanism underlying the BOLD signal, which includes a mismatch between neuronally driven increases in blood flow and a corresponding increase in oxygen use, appears to be intact in areas of chronic diaschisis.

scholarly journals Regional Cerebral Blood Flow and BOLD Responses in Conscious and Anesthetized Rats under Basal and Hypercapnic Conditions: Implications for Functional MRI Studies

2003 ◽  
Vol 23 (4) ◽  
pp. 472-481 ◽  
Author(s):  
Kenneth Sicard ◽  
Qiang Shen ◽  
Mathew E. Brevard ◽  
Ross Sullivan ◽  
Craig F. Ferris ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Functional Mri ◽  
Blood Gases ◽  
Blood Oxygen Level Dependent ◽  
Cerebrovascular Reactivity ◽  
Planar Imaging ◽  
Mri Studies ◽  
Bold Responses ◽  
Awake Condition

Anesthetics, widely used in magnetic resonance imaging (MRI) studies to avoid movement artifacts, could have profound effects on cerebral blood flow (CBF) and cerebrovascular coupling relative to the awake condition. Quantitative CBF and tissue oxygenation (blood oxygen level–dependent [BOLD]) were measured, using the continuous arterial-spin-labeling technique with echo-planar-imaging acquisition, in awake and anesthetized (2% isoflurane) rats under basal and hypercapnic conditions. All basal blood gases were within physiologic ranges. Blood pressure, respiration, and heart rates were within physiologic ranges in the awake condition but were depressed under anesthesia ( P < 0.05). Regional CBF was heterogeneous with whole-brain CBF values of 0.86 ± 0.25 and 1.27 ± 0.29 mL · g–1 · min–1 under awake and anesthetized conditions, respectively. Surprisingly, CBF was markedly higher (20% to 70% across different brain conditions) under isoflurane-anesthetized condition compared with the awake state ( P < 0.01). Hypercapnia decreased pH, and increased Pco2 and Po2. During 5% CO2 challenge, under awake and anesthetized conditions, respectively, CBF increased 51 ± 11% and 25 ± 4%, and BOLD increased 7.3 ± 0.7% and 5.4 ± 0.4%. During 10% CO2 challenge, CBF increased 158 ± 28% and 47 ± 11%, and BOLD increased 12.5 ± 0.9% and 7.2 ± 0.5%. Since CBF and BOLD responses were substantially higher under awake condition whereas blood gases were not statistically different, it was concluded that cerebrovascular reactivity was suppressed by anesthetics. This study also shows that perfusion and perfusion-based functional MRI can be performed in awake animals.

Innervation of endoneurial microvessels in human sural nerve

1992 ◽  
Vol 50 (1) ◽  
pp. 920-921
Author(s):  
John L. Beggs ◽  
Peter C. Johnson ◽  
Astrid G. Olafsen ◽  
C. Jane Watkins
Keyword(s):  
Blood Flow ◽  
Blood Vessels ◽  
Blood Supply ◽  
Peripheral Nerves ◽  
Sural Nerve ◽  
Nerve Fibers ◽  
Arterial Supply ◽  
Autonomic Nerve ◽  
Vasa Nervorum ◽  
Endoneurial Blood Flow

The blood supply (vasa nervorum) to peripheral nerves is composed of an interconnected dual circulation. The endoneurium of nerve fascicles is maintained by the intrinsic circulation which is composed of microvessels primarily of capillary caliber. Transperineurial arterioles link the intrinsic circulation with the extrinsic arterial supply located in the epineurium. Blood flow in the vasa nervorum is neurogenically influenced (1,2). Although a recent hypothesis proposes that endoneurial blood flow is controlled by the action of autonomic nerve fibers associated with epineurial arterioles (2), our recent studies (3) show that in addition to epineurial arterioles other segments of the vasa nervorum are also innervated. In this study, we examine blood vessels of the endoneurium for possible innervation.

Correlation of γ-radioactivity and Scanning Electron Microscopy in measurement of retention of 111Indium-labeled canine endothelial cells on synthetic vascular grafts

1989 ◽  
Vol 47 ◽  
pp. 886-887
Author(s):  
E.J. Prendiville ◽  
S. Laliberté Verdon ◽  
K. E. Gould ◽  
K. Ramberg ◽  
R. J. Connolly ◽  
...  
Keyword(s):  
Blood Flow ◽  
Ex Vivo ◽  
Vascular Grafts ◽  
Retention Data ◽  
Vascular Prostheses ◽  
Group 4 ◽  
Human Fibronectin ◽  
Insufficient Time ◽  
Group 3 ◽  
Group 2

Endothelial cell (EC) seeding is postulated as a mechanism of improving patency in small caliber vascular grafts. However the majority of seeded EC are lost within 24 hours of restoration of blood flow in previous canine studies . We postulate that the cells have insufficient time to fully develop their attachment to the graft surface prior to exposure to hemodynamic stress. We allowed EC to incubate on fibronectin-coated ePTFE grafts for four different time periods after seeding and measured EC retention after perfusion in a canine ex vivo shunt circuit.Autologous canine EC, were enzymatically harvested, grown to confluence, and labeled with 30 μCi 111 Indium-oxine/80 cm 2 flask. Four groups of 5 cm x 4 mm ID ePTFE vascular prostheses were coated with 1.5 μg/cm.2 human fibronectin, and seeded with 1.5 x 105 EC/ cm.2. After seeding grafts in Group 1 were incubated in complete growth medium for 90 minutes, Group 2 were incubated for 24 hours, Group 3 for 72 hours and Group 4 for 6 days. Grafts were then placed in the canine ex vivo circuit, constructed between femoral artery and vein, and subjected to blood flow of 75 ml per minute for 6 hours. Continuous counting of γ-activity was made possible by placing the seeded graft inside the γ-counter detection crystal for the duration of perfusion. EC retention data after 30 minutes, 2 hours and 6 hours of flow are shown in the table.

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