scholarly journals Relationship between intraocular, blood and cerebrospinal fluid pressures: a theoretical approach

2019 ◽  
Vol 2 (3) ◽  
pp. 9-13
Author(s):  
Giovanna Guidoboni ◽  
Fabrizia Salerni ◽  
Rodolfo Repetto ◽  
Marcela Szopos ◽  
Alon Harris
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cerebrospinal Fluid ◽  
Intraocular Pressure ◽  
Theoretical Approach ◽  
Central Vein ◽  
Csf Pressure ◽  
Vein Occlusion ◽  
Arterial Blood ◽  
Pathological Conditions

Intraocular pressure (IOP), arterial blood pressure (PA), and cerebrospinal fluid (CSF) pressure have been identified as major players in several ocular pathologies, including glaucoma, central vein occlusion, and papilledema, to name a few. IOP, PA, and CSF pressures are not independent from each other. For example, aqueous humor and CSF flows, whose mechanics contribute to establish IOP and CSF pressure levels, originate from blood flow, which is driven by PA. As a consequence, it is difficult to experimentally isolate IOP, PA, and CSF pressure and to disentangle their effect in pathological conditions. Here we utilize a theoretical approach to address this issue.

Regulation of Choroidal Blood Flow during Combined Changes in Intraocular Pressure and Arterial Blood Pressure

2007 ◽  
Vol 48 (8) ◽  
pp. 3768 ◽  
Author(s):  
Elzbieta Polska ◽  
Christian Simader ◽  
Gu¨nter Weigert ◽  
Arno Doelemeyer ◽  
Julia Kolodjaschna ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Intraocular Pressure ◽  
Arterial Blood Pressure ◽  
Choroidal Blood Flow ◽  
Arterial Blood

Effects of prostaglandins E1, E2, A1, A2, and F2α on canine carotid arterial blood flow, cerebrospinal fluid pressure, and intraocular pressure

1973 ◽  
Vol 38 (1) ◽  
pp. 32-39 ◽  
Author(s):  
Jiro Nakano ◽  
Alvin C. K. Chang ◽  
Robert G. Fisher
Keyword(s):  
Blood Flow ◽  
Cerebrospinal Fluid ◽  
Intraocular Pressure ◽  
Arterial Pressure ◽  
Fluid Pressure ◽  
Systemic Arterial Pressure ◽  
Cerebrospinal Fluid Pressure ◽  
Arterial Blood Flow ◽  
Arterial Blood ◽  
Carotid Arterial

✓ The effects of intra-arterial (i.a.) or intravenous (i.v.) injection of prostaglandins E1, (PGE1), E2 (PGE2), A1 (PGA1), A2 (PGA2), and F2α (PGF2α) on the carotid circulation, intraocular pressure (IOP), and cerebrospinal fluid pressure (CSFP) in anesthetized dogs are reported. Direct i.a. injection of PGE1, PGE2, or PGA2 decreases the carotid vascular resistance whereas PGF2α increases it. The i.v. injection of PGE1, PGE2, and PGA2 increases heart rate, carotid arterial blood flow, IOP, and CSFP as systemic arterial pressure decreases, while the i.v. injection of PGF2α decreases all but the IOP. Both systemic arterial pressure and IOP increase during a single i.v. infusion and decrease during a continuous i.v. infusion of PGF2α. This suggests that the changes in IOP and CSFP by the prostaglandins are not only a direct effect but also reflect indirect influence on carotid arterial blood flow. During a continuous i.v. infusion of PGE1, PGE2, or PGA2, carotid arterial blood flow gradually decreases toward control values after its initial marked increase. It is concluded that a single i.a. or i.v. injection or a short i.v. (10 min) infusion of PGE1 or PGE2 may be more effective than a prolonged continuous i.v. infusion of PGE1 or PGE2 for alleviating cerebral vascular spasm.

Influence of systemic and cerebral vascular factors on the cerebrospinal fluid pulse waves

1977 ◽  
Vol 46 (1) ◽  
pp. 36-45 ◽  
Author(s):  
Jürgen Hamer ◽  
Ekhart Alberti ◽  
Siegfried Hoyer ◽  
Klaus Wiedemann
Keyword(s):  
Blood Pressure ◽  
Cerebrospinal Fluid ◽  
Arterial Blood Pressure ◽  
Pulse Amplitude ◽  
Cardiac Insufficiency ◽  
Right Atrial ◽  
Csf Pressure ◽  
Arterial Blood ◽  
Pulse Waves ◽  
The Right

✓ In anesthetized, artificially ventilated dogs, the intracranial cerebrospinal fluid (CSF) pulse waves were studied simultaneously with the central aortic pressure, central venous pressure (CVP), and the sagittal sinus pressure under physiological conditions and in normovolemic arterial hypotension and hypertension, in acute cardiac insufficiency of the right atrium, in raised intracranial pressure (ICP), and in arterial hypoxemia. The physiological CSF pulsations are shown to be mainly arterial in origin. In the diastolic phase, the descending part of the pulse curve can be modified by venous superpositions coinciding with the right atrial “A” wave. With increase of ICP the configuration of the CSF pulsations changes: the venous superpositions disappear and the waves become more and more arterial in shape. Furthermore, the pulse amplitude increases considerably. The same change can be observed when cerebral vessels are dilated by arterial hypoxemia. During cardiac insufficiency and consecutive increase of CVP, the CSF pulse curve is venous in shape and the right atrial “A” wave predominates. In arterial hypotension, CSF pressure decreased. Conversely, in angiotensin-induced systemic arterial hypertension, CSF pressure and its pulse amplitude increased. It is concluded that both systemic arterial blood pressure and cerebrovascular reactivity are major determinants for the shape and the pressure amplitude of the intracranial CSF pulse waves. In the presence of cerebral vasodilatation, systemic arterial blood pressure may be an important factor in raising ICP and altering the brain tissue compliance, because cerebral vascular damping of the arterial pulse is diminished and the arterial pressure head may be directly transmitted to the cerebral capillary bed.

scholarly journals Attenuated Microcirculation in Small Metastatic Tumors in Murine Liver

Pharmaceutics ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 703
Author(s):  
Arturas Ziemys ◽  
Vladimir Simic ◽  
Miljan Milosevic ◽  
Milos Kojic ◽  
Yan Ting Liu ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Liver Metastases ◽  
Clinical Success ◽  
Metastatic Cancer ◽  
In Vivo Studies ◽  
Central Vein ◽  
Tumor Perfusion ◽  
Metastatic Tumors ◽  
Liver Lobule

Metastatic cancer disease is the major cause of death in cancer patients. Because those small secondary tumors are clinically hardly detectable in their early stages, little is known about drug biodistribution and permeation into those metastatic tumors potentially contributing to insufficient clinical success against metastatic disease. Our recent studies indicated that breast cancer liver metastases may have compromised perfusion of intratumoral capillaries hindering the delivery of therapeutics for yet unknown reasons. To understand the microcirculation of small liver metastases, we have utilized computational simulations to study perfusion and oxygen concentration fields in and around the metastases smaller than 700 µm in size at the locations of portal vessels, central vein, and liver lobule acinus. Despite tumor vascularization, the results show that blood flow in those tumors can be substantially reduced indicating the presence of inadequate blood pressure gradients across tumors. A low blood pressure may contribute to the collapsed intratumoral capillary lumen limiting tumor perfusion that phenomenologically corroborates with our previously published in vivo studies. Tumors that are smaller than the liver lobule size and originating at different lobule locations may possess a different microcirculation environment and tumor perfusion. The acinus and portal vessel locations in the lobule were found to be the most beneficial to tumor growth based on tumor access to blood flow and intratumoral oxygen. These findings suggest that microcirculation states of small metastatic tumors can potentially contribute to physiological barriers preventing efficient delivery of therapeutic substances into small tumors.

Effects of nicotine on canine intestinal blood flow and oxygen consumption

1984 ◽  
Vol 246 (2) ◽  
pp. G195-G203
Author(s):  
R. H. Gallavan ◽  
Y. Tsuchiya ◽  
E. D. Jacobson
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Oxygen Consumption ◽  
Muscle Tension ◽  
Intestinal Blood Flow ◽  
Mesenteric Blood Flow ◽  
State Response ◽  
Arterial Blood ◽  
Intestinal Circulation

The purpose of this study was to determine the effects of nicotine on intestinal blood flow and oxygen consumption. The intravenous infusion of nicotine at doses corresponding to those experienced by smokers produced a transient increase in systemic arterial blood pressure and mesenteric blood flow. Subsequently a steady-state response developed that consisted of a reduction in mesenteric blood flow due to both a decrease in blood pressure and an increase in intestinal vascular resistance. This increase in resistance was probably due to increased levels of circulating catecholamines. The intra-arterial infusion of nicotine into the intestinal circulation at doses experienced by the average smoker had no effect on either intestinal blood flow or oxygen consumption. Similarly, under in vitro conditions nicotine had no direct effect on intestinal vascular smooth muscle tension. Thus, nicotine appears to reduce intestinal blood flow indirectly as a result of its systemic effects.

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