Verification of Mathematical Model for Bioimpedance Diagnostics of the Blood Flow in Cerebral Vessels

2019 ◽  
pp. 251-259 ◽  
Author(s):  
Anna A. Kiseleva ◽  
Petr V. Luzhnov ◽  
Dmitry M. Shamaev
Keyword(s):  
Mathematical Model ◽  
Blood Flow ◽  
Cerebral Vessels

A MATHEMATICAL MODEL OF ANEURYSM OF CIRCLE OF WILLIS

1995 ◽  
Vol 03 (03) ◽  
pp. 653-659 ◽  
Author(s):  
J. J. NIETO ◽  
A. TORRES
Keyword(s):  
Differential Equation ◽  
Mathematical Model ◽  
Ordinary Differential Equation ◽  
Blood Flow ◽  
Nonlinear Analysis ◽  
Existence Of Solutions ◽  
Circle Of Willis ◽  
Second Order ◽  
Qualitative Properties

We introduce a new mathematical model of aneurysm of the circle of Willis. It is an ordinary differential equation of second order that regulates the velocity of blood flow inside the aneurysm. By using some recent methods of nonlinear analysis, we prove the existence of solutions with some qualitative properties that give information on the causes of rupture of the aneurysm.

Changes in the tone of cerebral vessels in patients with bronchial asthma after glomectomy

1982 ◽  
Vol 63 (1) ◽  
pp. 56-56
Author(s):  
E. S. Karashurov ◽  
S. E. Karashurov
Keyword(s):  
Blood Flow ◽  
Bronchial Asthma ◽  
Cerebral Vessels ◽  
Acid Base Balance ◽  
Acid Base ◽  
Base Balance ◽  
The Brain

Frequent complications of glomectomy are headaches and a mild, less-like state for several days or weeks after surgery, and sometimes hemi- and monoparesis. The reasons for these complications have not yet been revealed. In search of their explanation, we decided to study the volumetric blood flow of the brain and the acid-base state (ACS). Volumetric blood flow was studied by rheoencephalography (REG) in 43 patients, and acid base balance - in 100 patients (age from 22 to 67 years). The course of bronchial asthma before the operation in the examined patients was moderate and severe.

Mathematical model of the capillary blood flow and transcapillary fluid exchange

1976 ◽  
Vol 11 (5) ◽  
pp. 748-752
Author(s):  
V. M. Zaiko ◽  
V. G. Aleksandrov
Keyword(s):  
Mathematical Model ◽  
Blood Flow ◽  
Capillary Blood ◽  
Capillary Blood Flow ◽  
Fluid Exchange

Interaction among autoregulation, CO2 reactivity, and intracranial pressure: a mathematical model

1998 ◽  
Vol 274 (5) ◽  
pp. H1715-H1728 ◽  
Author(s):  
Mauro Ursino ◽  
Carlo Alberto Lodi
Keyword(s):  
Mathematical Model ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Intracranial Pressure ◽  
Nonlinear Interaction ◽  
Cerebral Blood Volume ◽  
Cerebral Hemodynamics ◽  
Pial Arteries ◽  
Arterial Circulation ◽  
Neurosurgical Patients

The relationships among cerebral blood flow, cerebral blood volume, intracranial pressure (ICP), and the action of cerebrovascular regulatory mechanisms (autoregulation and CO2 reactivity) were investigated by means of a mathematical model. The model incorporates the cerebrospinal fluid (CSF) circulation, the intracranial pressure-volume relationship, and cerebral hemodynamics. The latter is based on the following main assumptions: the middle cerebral arteries behave passively following transmural pressure changes; the pial arterial circulation includes two segments (large and small pial arteries) subject to different autoregulation mechanisms; and the venous cerebrovascular bed behaves as a Starling resistor. A new aspect of the model exists in the description of CO2 reactivity in the pial arterial circulation and in the analysis of its nonlinear interaction with autoregulation. Simulation results, obtained at constant ICP using various combinations of mean arterial pressure and CO2 pressure, substantially support data on cerebral blood flow and velocity reported in the physiological literature concerning both the separate effects of CO2 and autoregulation and their nonlinear interaction. Simulations performed in dynamic conditions with varying ICP underline the existence of a significant correlation between ICP dynamics and cerebral hemodynamics in response to CO2 changes. This correlation may significantly increase in pathological subjects with poor intracranial compliance and reduced CSF outflow. In perspective, the model can be used to study ICP and blood velocity time patterns in neurosurgical patients in order to gain a deeper insight into the pathophysiological mechanisms leading to intracranial hypertension and secondary brain damage.

Shock Waves in Mathematical Models of the Aorta

1970 ◽  
Vol 37 (1) ◽  
pp. 34-37 ◽  
Author(s):  
George Rudinger
Keyword(s):  
Mathematical Model ◽  
Blood Flow ◽  
Shock Waves ◽  
Method Of Characteristics ◽  
Wave Form ◽  
Shock Formation ◽  
Rapid Flow ◽  
Latex Tube ◽  
Flow Changes ◽  
The Mathematical Model

If the nonlinear equations for nonsteady blood flow are solved by the method of characteristics, shock discontinuities may develop as a result of omitting from the mathematical model some aspect of the system that becomes significant at rapid flow changes. As an illustration, the flow from the heart into the aorta at the beginning of systole is analyzed. An equation is derived which yields shock formation distances between a few centimeters and several meters depending on the elastic properties of the aorta. Since knowledge of the actual wave form would be useful for computer programming, a few exploratory experiments were performed with an unrestrained latex tube. They indicated wave transitions extending over several tube diameters, but maximum steepening of the wave has not yet been achieved.

Influence of Inosine on Cerebral Hemodynamics in Space Motion Sickness in Experimental Animals

2021 ◽  
Vol 21 ◽  
Author(s):  
Asie N. Useinova ◽  
Vitalii Kaliberdenko ◽  
Igor D. Sapegin ◽  
Shanmugaraj Kulanthaivel ◽  
Michael V. Shterenshis ◽  
...  
Keyword(s):  
Blood Flow ◽  
Motion Sickness ◽  
Vascular Reactivity ◽  
Visual Stimulation ◽  
Cerebrovascular Disorders ◽  
Cerebral Vessels ◽  
Local Blood Flow ◽  
Experimental Animals ◽  
Space Motion Sickness ◽  
Space Motion

Background: Motion sickness occurs worldwide in healthy individuals regardless of age, ethnicity, or gender. It is an acute disorder, it can also present as a chronic disorder in some individuals. Motion sickness not only includes vomiting and nausea, besides this, it includes other features such as pallor of varying degrees, cold sweating, headache, drowsiness, increased salivation, and cranial pain which is severe. Some of the other assessment scales can interpret sickness on exposure to virtual or visual stimulation and while travelling in different types of transport. Aim: The aim our research is to study the effect of the drug on the level of blood flow and vascular reactivity of cerebral vessels when simulating changes in cerebral circulation in terrestrial conditions characteristic of hypogravity. Methods: Chronic experiments were performed on non-anesthetized rabbits with large hemispheres, thalamus and hypothalamus were implanted with the needle-platinum electrodes 150 mm in diameter in the cortex, and local blood flow and vascular reactivity were recorded accordingly. Cerebrovascular disturbances were modeled using a MSAOP (motion sickness of animals in the anti-orthostatic position) with an inclined angle of 45 ° for 2 hours. Local blood flow (BF) was measured in ml/min/100 g of tissue by the method of registration of hydrogen clearance. The vasodilator coefficient of reactivity (CrCO2) was calculated by the ratio of BF against the background of inhalation of a mixture of 7% CO2 with air to the initial BF; vasoconstrictor - in relation to BF on the background of inhalation of 100% O2 to the initial BF (CrO2). A series of experiments was carried out with different routes of drug administration: First, inosine was administered intravenously at a dose of 5 mg/kg immediately before the start of SMS modeling, Same dose per oral was administered 30 minutes before the start of exposure. As a control, we used the results of experimental animals under similar conditions without the administration of the drugs. Results: Inosine has pronounced protective properties in cerebrovascular disorders on the background of space motion sickness (SMS) modeling, which is manifested by normalization of BF and restoration of compensatory reactions of cerebral vessels. In the mechanism of cerebroprotective action of inosine, it is able to correct the metabolic processes which plays an important role and helps to increase the compensatory capabilities and functional stability of the cerebrovascular system under gravitational influences. Conclusion: When using inosine per orally, the effects are more pronounced than when administered intravenously, which should be taken into account when using it for the prevention of cerebrovascular disorders in extreme conditions.

A MATHEMATICAL MODEL FOR BLOOD FLOW UNDER PERIODIC ACCELERATION

2010 ◽  
Author(s):  
Abdalla Wassf Isaac ◽  
Mikhial Maher Mathuieu
Keyword(s):  
Mathematical Model ◽  
Blood Flow ◽  
Periodic Acceleration

scholarly journals Transient Monocular Blindness

1977 ◽  
Vol 4 (3) ◽  
pp. 143-150 ◽  
Author(s):  
R.T. Ross
Keyword(s):  
Blood Flow ◽  
Therapeutic Agents ◽  
Current Treatment ◽  
Surgical Correction ◽  
Cerebral Vessels ◽  
Retinal Blood Flow ◽  
Future Studies ◽  
Transient Monocular Blindness ◽  
Effect Of Treatment ◽  
Retinal Emboli

SUMMARY:This paper is a review of the causes of intermittent monocular blindness. The nature of cholesterol and platelet retinal emboli is discussed. Their sources, the frequency with which they may cause transient or fixed blindness and the association between these emboli and pathology of the major cerebral vessels and other organs is discussed.Consideration is given to the equally important abnormalities of platelet behavior and to some of the physiology of retinal blood flow and non-embolic blindness.The current treatment of this symptom may be anticoagulation, surgical correction of a stenotic artery or both. The effect of treatment is unpredictable and in some situations the rationale is suspect.This review may provide a summary on which to base future studies of the effectiveness of various therapeutic agents.

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