scholarly journals Topology and Hemodynamics of the Cortical Cerebrovascular System

2012 ◽  
Vol 32 (6) ◽  
pp. 952-967 ◽  
Author(s):  
Sven Hirsch ◽  
Johannes Reichold ◽  
Matthias Schneider ◽  
Gábor Székely ◽  
Bruno Weber
Keyword(s):  
Blood Flow ◽  
Vascular System ◽  
Current Knowledge ◽  
Energy Requirement ◽  
Vascular Anatomy ◽  
Neuronal Loss ◽  
Energy Substrates ◽  
Detailed Understanding ◽  
Cerebrovascular System ◽  
The Brain

The cerebrovascular system continuously delivers oxygen and energy substrates to the brain, which is one of the organs with the highest basal energy requirement in mammals. Discontinuities in the delivery lead to fatal consequences for the brain tissue. A detailed understanding of the structure of the cerebrovascular system is important for a multitude of (patho-)physiological cerebral processes and many noninvasive functional imaging methods rely on a signal that originates from the vasculature. Furthermore, neurodegenerative diseases often involve the cerebrovascular system and could contribute to neuronal loss. In this review, we focus on the cortical vascular system. In the first part, we present the current knowledge of the vascular anatomy. This is followed by a theory of topology and its application to vascular biology. We then discuss possible interactions between cerebral blood flow and vascular topology, before summarizing the existing body of the literature on quantitative cerebrovascular topology.

scholarly journals Two-Photon Microscopy as a Tool to Study Blood Flow and Neurovascular Coupling in the Rodent Brain

2012 ◽  
Vol 32 (7) ◽  
pp. 1277-1309 ◽  
Author(s):  
Andy Y Shih ◽  
Jonathan D Driscoll ◽  
Patrick J Drew ◽  
Nozomi Nishimura ◽  
Chris B Schaffer ◽  
...  
Keyword(s):  
Blood Flow ◽  
Laser Scanning ◽  
Vascular System ◽  
Neurovascular Coupling ◽  
Laser Scanning Microscopy ◽  
Small Scale ◽  
Two Photon Microscopy ◽  
Two Photon ◽  
Rats And Mice ◽  
The Brain

The cerebral vascular system services the constant demand for energy during neuronal activity in the brain. Attempts to delineate the logic of neurovascular coupling have been greatly aided by the advent of two-photon laser scanning microscopy to image both blood flow and the activity of individual cells below the surface of the brain. Here we provide a technical guide to imaging cerebral blood flow in rodents. We describe in detail the surgical procedures required to generate cranial windows for optical access to the cortex of both rats and mice and the use of two-photon microscopy to accurately measure blood flow in individual cortical vessels concurrent with local cellular activity. We further provide examples on how these techniques can be applied to the study of local blood flow regulation and vascular pathologies such as small-scale stroke.

On the first partial skull of an ankylosaurian dinosaur from the Lower Cretaceous of the Isle of Wight, southern England

1996 ◽  
Vol 133 (3) ◽  
pp. 299-310 ◽  
Author(s):  
David B. Norman ◽  
Tamsin Faiers
Keyword(s):  
Vascular System ◽  
Cranial Nerves ◽  
Vascular Anatomy ◽  
Dorsal Surface ◽  
Significant Component ◽  
Isle Of Wight ◽  
Strong Separation ◽  
Nasal Region ◽  
Neural Anatomy ◽  
The Brain

AbstractThe specimen is identified as the partial cranium of a nodosaurid ankylosaur (Ornithischia: Thyreophora) on the basis of the presence of bone which is fused to the dorsal surface of the skull and has secondarily closed the upper temporal fenestrae. The only unequivocally nodosaurid material recovered from the Isle of Wight to date comes from Wealden facies, and has been referred to the genus Polacanthus; it is considered highly probable that this new skull is referable to the same genus. Despite having undergone abrasion, through post-emergence water-rolling, the skull and cranial walls have proved to be relatively informative of the general anatomy of the braincase and the neural and vascular anatomy of this part of the head. The anatomy of the braincase of most ankylosaurs (with the notable exception of the juvenile specimens of the ankylosaurid Pinacosaurus) is surprisingly poorly known, despite the relative abundance of cranial material in North American and Asian collections.The cranial neural and vascular anatomy is well shown in this specimen and enables the first detailed description of nodosaurid endocranial structures. The general form of the brain can be outlined from the structure of the endocast and the principal lobes can be identified; the majority of the cranial nerves have been identified, and a significant component of the associated vascular system is also visible. In most respects the endocast shows a neural anatomy which is common to that known in most dinosaurs. When compared to their nearest relatives, the ankylosaurid ankylosaurs (Euoplocephalus), the nodosaurid endocranial cast shows a more pronounced cerebral flexure, a forebrain which is broader and more expanded dorsally, and a more prominent cerebellum (although there is no evidence for a floccular lobe); there are minor differences in the arrangement of the cranial nerves, and the dorsal portions of the vascular system are better shown.Because of erosion, the olfactory lobes of this specimen of cf. Polacanthus are not preserved, and cannot be compared to those of ankylosaurid ankylosaurs; the latter are unusual in the strong separation of the lobes (reflected in the divergent olfactory stalks); this feature may be associated with the very complex passages within the nasal region of the skull, which are lacking in the nodosaurids described to date.

scholarly journals Peculiarities of cerebral blood flow in patients with chronic diffuse liver diseases of viral etiology

2014 ◽  
Vol 95 (6) ◽  
pp. 859-865 ◽  
Author(s):  
T S Morozova ◽  
I F Grishina ◽  
I A Gurikova
Keyword(s):  
Blood Flow ◽  
Liver Cirrhosis ◽  
Cerebral Blood Flow ◽  
Liver Diseases ◽  
Vascular System ◽  
Cerebral Arteries ◽  
Vascular Wall ◽  
Viral Etiology ◽  
The Brain ◽  
Diffuse Liver Diseases

Aim. To study the features of cerebral blood flow at different structural and functional levels of the brain vascular system in patients with chronic hepatitis and cirrhosis of viral etiology. Methods. A comprehensive ultrasound examination of the brain vascular system using an algorithm of cerebral arterial and venous blood flow examination based on the concept of the brain vascular system construction considering five structural and functional levels was performed in 65 chronic viral hepatitis patients and 61 patients with liver cirrhosis of viral etiology. The examination of the main brain arteries was performed using duplex scanning ultrasound SSD-5500 scanner («Aloka», Japan) with 5-12 MHz linear transducers. Examination of intracranial vessels was performed by transcranial color duplex scanning using ultrasonic SSD-5500 and «Sonoline G60» scanners («Siemens», Germany) with linear and phased 2.1-2.5 MHz transducers. Control group consisted of 50 healthy persons. Results. Remodeling of the cerebral arteries: the expansion of the lumen of the main cerebral vessels, reduction of blood flow in the carotid and middle cerebral arteries, decreased elasticity and increased vascular wall rigidity and, as a consequence, a change in vascular resistance and cerebral blood flow disturbance occurs in patients with chronic viral liver diseases. Identified changes of blood flow parameters at all levels of structural and functional brain perfusion indicate the presence of cerebral microangiopathy and arteriopathy based on the development of arteriosclerosis of main arteries and all penetrating arteries and arterioles in patients with chronic diffuse liver diseases. Conclusion. Adaptive remodeling of the vascular wall of the main cerebral arteries which provides an adequate regulatory response is found in patients with hepatitis B and C-associated liver cirrhosis. The reduction of blood supply to the brain, depletion of functional vascular reserve and development of intracranial venous circulatory distress are seen in patients with liver cirrhosis associated with viral hepatitis.

scholarly journals The interplay of blood flow and temperature in regional hyperthermia: a mathematical approach

2021 ◽  
Vol 8 (1) ◽  
pp. 201234
Author(s):  
Jesús J. Bosque ◽  
Gabriel F. Calvo ◽  
Víctor M. Pérez-García ◽  
María Cruz Navarro
Keyword(s):  
Blood Flow ◽  
Brain Tumours ◽  
Adjuvant Radiotherapy ◽  
Current Knowledge ◽  
Future Research ◽  
Mathematical Approach ◽  
Regional Hyperthermia ◽  
Therapeutic Modalities ◽  
Temperature Levels ◽  
The Brain

In recent decades, hyperthermia has been used to raise oxygenation levels in tumours undergoing other therapeutic modalities, of which radiotherapy is the most prominent one. It has been hypothesized that oxygenation increases would come from improved blood flow associated with vasodilation. However, no test has determined whether this is a relevant assumption or other mechanisms might be acting. Additionally, since hyperthermia and radiotherapy are not usually co-administered, the crucial question arises as to how temperature and perfusion in tumours will change during and after hyperthermia. Overall, it would seem necessary to find a research framework that clarifies the current knowledge, delimits the scope of the different effects and guides future research. Here, we propose a simple mathematical model to account for temperature and perfusion dynamics in brain tumours subjected to regional hyperthermia. Our results indicate that tumours in well-perfused organs like the brain might only reach therapeutic temperatures if their vasculature is highly disrupted. Furthermore, the characteristic times of return to normal temperature levels are markedly shorter than those required to deliver adjuvant radiotherapy. According to this, a mechanistic coupling of perfusion and temperature would not explain any major oxygenation boost in brain tumours immediately after hyperthermia.

scholarly journals Neuronal and Cerebrovascular Complications in Coronavirus Disease 2019

2020 ◽  
Vol 11 ◽  
Author(s):  
Mudasir S. Andrabi ◽  
Shaida A. Andrabi
Keyword(s):  
Current Knowledge ◽  
Neurological Complications ◽  
Cerebrovascular Complications ◽  
Pharmacological Targets ◽  
Crucial Component ◽  
Cellular Components ◽  
Cerebrovascular System ◽  
Taste And Smell ◽  
The Brain

Coronavirus disease 2019 (COVID-19) is a pandemic disease resulting from severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection, primarily in the respiratory tract. This pandemic disease has affected the entire world, and the pathobiology of this disease is not yet completely known. The Interactions of SARS-CoV-2 proteins with different cellular components in the host cell may be necessary for understanding the disease mechanism and identifying crucial pharmacological targets in COVID-19. Studies have suggested that the effect of SARS-CoV-2 on other organs, including the brain, maybe critical for understanding the pathobiology of COVID-19. Symptoms in COVID-19 patients, including impaired consciousness dizziness, headache, loss of taste and smell, vision problems, and neuromuscular pain, suggest that neuronal complications comprise a crucial component of COVID-19 pathobiology. A growing body of literature indicates that SARS-CoV-2 can enter the brain, leading to neuronal defects in COVID-19 patients. Other studies suggest that SARS-CoV-2 may aggravate neuronal complications due to its effects on the cerebrovascular system. Emerging pieces of evidence show that stroke can be one of the leading neurological complications in COVID-19. In this review, we describe the observations about neuronal complications of COVID-19 and how SARS-CoV-2 may invade the brain. We will also discuss the cerebrovascular problems and occurrence of stroke in COVID-19 patients. We will also present the observations and our views about the potential pharmacological strategies and targets in COVID-19. We hope this review will help comprehend the current knowledge of neuronal and cerebrovascular complications from SARS-CoV-2 infections and highlight the possible long-term consequences of SARS-CoV-2 on the human brain.

Microvascular features that suggest effectors of blood-flow regulation in the brain: Evidence by SEM of corrosion casts of intracerebral vessels

1990 ◽  
Vol 48 (3) ◽  
pp. 274-275
Author(s):  
Enrico D.F. Motti ◽  
Hans-Georg Imhof ◽  
Gazi M. Yasargil
Keyword(s):  
Blood Flow ◽  
Perfusion Pressure ◽  
Corrosion Casts ◽  
Cerebral Microcirculation ◽  
Pial Arteries ◽  
Random Occurrence ◽  
Brain Arteries ◽  
Homogeneous Network ◽  
The Brain

Physiologists have devoted most attention in the cerebrovascular tree to the arterial side of the circulation which has been subdivided in three levels: 1) major brain arteries which keep microcirculation constant despite changes in perfusion pressure; 2) pial arteries supposed to be effectors regulating microcirculation; 3) intracerebral arteries supposed to be deprived of active cerebral blood flow regulating devices.The morphological search for microvascular effectors in the cerebrovascular bed has been elusive. The opaque substance of the brain confines in vivo investigation to the superficial pial arteries. Most morphologists had to limit their observation to the random occurrence of a favorable site in the practically two-dimensional thickness of diaphanized histological sections. It is then not surprising most investigators of the cerebral microcirculation refer to an homogeneous network of microvessels interposed between arterioles and venules.We have taken advantage of the excellent depth of focus afforded by the scanning electron microscope (SEM) to investigate corrosion casts obtained injecting a range of experimental animals with a modified Batson's acrylic mixture.

Fit Vs Faint: Assessing Work Causation in “Idiopathic Fall” Cases

2014 ◽  
Vol 19 (5) ◽  
pp. 3-12
Author(s):  
Lorne Direnfeld ◽  
David B. Torrey ◽  
Jim Black ◽  
LuAnn Haley ◽  
Christopher R. Brigham
Keyword(s):  
Blood Flow ◽  
Electrical Activity ◽  
Loss Of Consciousness ◽  
Brain Electrical Activity ◽  
Medical Terminology ◽  
Scientific Analysis ◽  
Medical Causation ◽  
The Individual ◽  
The Brain ◽  
Current Science

Abstract When an individual falls due to a nonwork-related episode of dizziness, hits their head and sustains injury, do workers’ compensation laws consider such injuries to be compensable? Bearing in mind that each state makes its own laws, the answer depends on what caused the loss of consciousness, and the second asks specifically what happened in the fall that caused the injury? The first question speaks to medical causation, which applies scientific analysis to determine the cause of the problem. The second question addresses legal causation: Under what factual circumstances are injuries of this type potentially covered under the law? Much nuance attends this analysis. The authors discuss idiopathic falls, which in this context means “unique to the individual” as opposed to “of unknown cause,” which is the familiar medical terminology. The article presents three detailed case studies that describe falls that had their genesis in episodes of loss of consciousness, followed by analyses by lawyer or judge authors who address the issue of compensability, including three scenarios from Arizona, California, and Pennsylvania. A medical (scientific) analysis must be thorough and must determine the facts regarding the fall and what occurred: Was the fall due to a fit (eg, a seizure with loss of consciousness attributable to anormal brain electrical activity) or a faint (eg, loss of consciousness attributable to a decrease in blood flow to the brain? The evaluator should be able to fully explain the basis for the conclusions, including references to current science.

Basic Ideas and Principles for Quantifying Regional Blood Flow with Nuclear Medical Techniques

1996 ◽  
Vol 35 (05) ◽  
pp. 181-185 ◽  
Author(s):  
H. Herzog
Keyword(s):  
Blood Flow ◽  
Nuclear Medicine ◽  
Regional Blood Flow ◽  
Visual Presentation ◽  
Regional Cerebral Blood ◽  
Basic Principles ◽  
Parametric Images ◽  
Major Application ◽  
Basic Ideas ◽  
The Brain

SummaryThe measurement of blood flow in various organs and its visual presentation in parametric images is a major application in nuclear medicine. The purpose of this paper is to summarize the most important nuclear medicine procedures used to quantify regional blood flow. Starting with the first concepts introduced by Fick and later by Kety-Schmidt the basic principles of measuring global and regional cerebral blood are discussed and their relationships are explained. Different applications and modifications realized first in PET- and later in SPECT-studies of the brain and other organs are described. The permeability and the extraction of the different radiopharmaceuticals are considered. Finally some important instrumental implications are compared.

Vorläufige Ergebnisse von 99mTc-HMPAO-SPECT-Untersuchungen bei endogenen Psychosen

1989 ◽  
Vol 28 (03) ◽  
pp. 88-91
Author(s):  
J. Schröder ◽  
H. Henningsen ◽  
H. Sauer ◽  
P. Georgi ◽  
K.-R. Wilhelm
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Regional Cerebral Blood Flow ◽  
Regions Of Interest ◽  
Post Mortem ◽  
Regional Cerebral Blood ◽  
Hmpao Spect ◽  
Endogenous Psychoses ◽  
The Brain ◽  
99Mtc Hmpao

18 psychopharmacologically treated patients (7 schizophrenics, 5 schizoaffectives, 6 depressives) were studied using 99mTc-HMPAO-SPECT of the brain. The regional cerebral blood flow was measured in three transversal sections (infra-/supraventricular, ventricular) within 6 regions of interest (ROI) respectively (one frontal, one parietal and one occipital in each hemisphere). Corresponding ROIs of the same section in each hemisphere were compared. In the schizophrenics there was a significantly reduced perfusion in the left frontal region of the infraventricular and ventricular section (p < 0.02) compared with the data of the depressives. The schizoaffectives took an intermediate place. Since the patients were treated with psychopharmaca, the result must be interpreted cautiously. However, our findings seem to be in accordance with post-mortem-, CT- and PET-studies presented in the literature. Our results suggest that 99mTc-HMPAO-SPECT may be helpful in finding cerebral abnormalities in endogenous psychoses.

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