The structure of the perivascular compartment in the old canine brain: a case study

2017 ◽  
Vol 131 (22) ◽  
pp. 2737-2744 ◽  
Author(s):  
Theodore P. Criswell ◽  
Matthew MacGregor Sharp ◽  
Howard Dobson ◽  
Ciara Finucane ◽  
Roy O. Weller ◽  
...  
Keyword(s):  
Blood Vessels ◽  
Regional Variation ◽  
Perivascular Spaces ◽  
Fixed Tissue ◽  
Anatomical Distribution ◽  
Canine Brain ◽  
Human Material ◽  
Anatomical Arrangement ◽  
Complete Layer ◽  
Cell Expression

Dilatation of periarteriolar spaces in MRI of the ageing human brains occurs in white matter (WM), basal ganglia and midbrain but not in cerebral cortex. Perivenous collagenous occurs in periventricular but not in subcortical WM. Here we test the hypotheses that (a) the capacity for dilatation of periarteriolar spaces correlates with the anatomical distribution of leptomeningeal cells coating intracerebral arteries and (b) the regional development of perivenous collagenous in the WM correlates with the population of intramural cells in the walls of veins. The anatomical distribution of leptomeningeal and intramural cells related to cerebral blood vessels is best documented by electron microscopy, requiring perfusion-fixed tissue not available in human material. We therefore analysed perfusion-fixed brain from a 12-year-old Beagle dog as the canine brain represents the anatomical arrangement in the human brain. Results showed regional variation in the arrangement of leptomeningeal cells around blood vessels. Arterioles are enveloped by one complete layer of leptomeninges often with a second incomplete layer in the WM. Venules showed incomplete layers of leptomeningeal cells. Intramural cell expression was higher in the post-capillary venules of the subcortical WM when compared with periventricular WM, suggesting that periventricular collagenosis around venules may be due to a lower resistance in the venular walls. It appears that the regional variation in the capacity for dilatation of arteriolar perivascular spaces in the white WM may be related to the number of perivascular leptomeningeal cells surrounding vessels in different areas of the brain.

Perivascular (Virchow–Robin) spaces

2021 ◽  
pp. 86-89
Keyword(s):  
Blood Vessels ◽  
Shape Change ◽  
Lymphatic Drainage ◽  
Brain Regions ◽  
Mechanical Trauma ◽  
Normal Brain ◽  
Perivascular Spaces ◽  
Mr Images ◽  
Lenticulostriate Artery ◽  
The Brain

Perivascular spaces; also known as the Virchow-Robin Spaces, they are pleurally lined, interstitial fluid-filled areas that surround certain blood vessels in various organs, especially the perforating arteries in the brain, with an immunological function. Dilated perivascular spaces are divided into three types. The first of these is on the lenticulostriate artery, the second is in the cortex following the path of the medullary artery, and the third is in the midbrain. Perivascular spaces can be detected as areas of dilatation on MR images. Although a limited number of perivascular spaces can be seen in a normal brain, the increase in the number of these spaces has been associated with the incidence of various neurodegenerative diseases. Different theories have been suggested about the tendency of the perivascular spaces to expand. Current theories include mechanical trauma due to cerebrospinal fluid pulsing, elongation of penetrating blood vessels, unusual vascular permeability, and increased fluid exudation. In addition, the brain tissue atrophy that occurs with aging; It is thought to contribute to the widening of perivascular spaces by causing shrinkage of arteries, altered arterial wall permeability, obstruction of lymphatic drainage pathways and vascular demyelination. It is assumed that the clinical significance of the dilation tendencies of the perivascular spaces is based on shape change rather than size. These spaces have been mostly observed in brain regions such as corpus callosum, cingulate gyrus, dentate nucleus, substantia nigra and various arterial basins including lenticulostriate artery and mesencephalothalamic artery. In conclusion, when sections are taken on MR imaging, it is possible that perivascular spaces may be confused with microvascular diseases and some neurodegenerative changes. In addition, perivascular spaces can be seen without pathological significance. Therefore, it would be appropriate to investigate the etiological relationship by evaluating the radiological findings and clinical picture together.

scholarly journals Morphology of perivascular spaces and enclosed blood vessels in young to middle-aged healthy adults at 7T: Dependences on age, brain region, and breathing gas

NeuroImage ◽  
2020 ◽  
Vol 218 ◽  
pp. 116978 ◽  
Author(s):  
Xiaopeng Zong ◽  
Chunfeng Lian ◽  
Jordan Jimenez ◽  
Koji Yamashita ◽  
Dinggang Shen ◽  
...  
Keyword(s):  
Blood Vessels ◽  
Brain Region ◽  
Healthy Adults ◽  
Perivascular Spaces ◽  
Middle Aged

The Pressure-Flow Relation for Plasma in Whole Organ Skeletal Muscle and Its Experimental Verification

1991 ◽  
Vol 113 (4) ◽  
pp. 452-457 ◽  
Author(s):  
Don W. Sutton ◽  
Geert W. Schmid-Scho¨nbein
Keyword(s):  
Skeletal Muscle ◽  
Blood Vessels ◽  
Gracilis Muscle ◽  
Low Flow ◽  
Third Order ◽  
Fixed Tissue ◽  
Pressure Flow ◽  
Flow Rates ◽  
Order Polynomial ◽  
Artificial Plasma

The whole-organ pressure-flow relation in resting rat skeletal muscle is examined for the flow of plasma. Due to the small size of the blood vessels in this organ, inertia and convective forces in the blood are negligible and viscous forces dominate. Direct measurements in the past have shown that skeletal muscle blood vessels are distensible. Theoretical formulations based on these measurements lead to a third order polynomial model for the pressure-flow relation. The purpose of the current study is to examine this relation experimentally in an isolated muscle organ. A high precision feedback controlled pump is used to perfuse artificial plasma into the vasodilated rat gracilis muscle. The results indicate that the pressure-flow curve in this tissue is nonlinear in the low flow region and almost linear at physiological flow rates, following closely the third order polynomial function. Vessel fixation with glutaraldehyde causes the curves to become linear at all pressures, indicating that vessel distention is the primary mechanism causing the nonlinearity. Furthermore, the resistance of the post-fixed tissue is determined by the pressure at which the fixative is perfused. At fixation pressures below 10 mmHg, the resistance is three times higher than in vessels fixed at normal physiological pressures. Dextran (229,000 Dalton) is used to obtain Newtonian perfusates at different viscosities. The pressure-flow relation is found to be linearly dependent on viscosity for all flow rates. Skeletal muscle has multiple arterial inflows. Separate perfusion of the two major arterial feeders in the rat gracilis muscle show that for low pressures the flow at each feeder is dependent on the pressure at the opposite feeder, whereas at normal pressures the flow becomes independent of the opposite feeder pressure. The hemodynamic resistance in plasma perfused vasodilated skeletal muscle depends on vessel distensibility, plasma viscosity, and can be closely modeled by a third order polynomial relation.

THE UNILATERAL ENDOMETRIAL REACTION IN THE GIANT FRUIT-BAT (PTEROPUS GIGANTEUS BRÜNNICH)

1953 ◽  
Vol 9 (1) ◽  
pp. 42-NP ◽  
Author(s):  
A. J. MARSHALL
Keyword(s):  
Corpus Luteum ◽  
Blood Vessels ◽  
Fallopian Tube ◽  
Uterine Horn ◽  
Asymmetric Reaction ◽  
Fruit Bat ◽  
Close Proximity ◽  
Anatomical Arrangement

In the giant fruit-bat of India, Burma and Ceylon, both ovaries and uterine horns are functional, but only one ovum is released each year after copulation. As the corpus luteum becomes active (but while the fertilized ovum is still in the Fallopian tube), a progestational reaction occurs in the horn adjacent to the ovary which contains the ruptured follicle, whereas the opposite horn retains its oestrous appearance. The site of this asymmetric reaction (at which implantation subsequently takes place) is confined to the extreme distal end of the horn, where uterine and ovarian tissues lie in close proximity. Blood vessels, some of them of an apparently sinusoidal nature, traverse the short intervening isthmus, and the corpus luteum is often formed at a distance of less than 2 mm from the endometrium. In view of this unusual anatomical arrangement, it is suggested that progesterone may pass directly from the ovulatory pole of the ovary to the uterine horn, either through the vessels described, or by way of the lymphatics and tissue spaces.

scholarly journals Species differences in the cerebellar distribution of six members of the Kv1 channel subfamily

2020 ◽  
Author(s):  
Olimpia E. Curran ◽  
Andrew W. Hubball ◽  
Philip D. Minor ◽  
Charles H. Knowles ◽  
Joanne E. Martin
Keyword(s):  
Purkinje Cells ◽  
Species Differences ◽  
Stellate Cell ◽  
Polyclonal Antibodies ◽  
Fixed Tissue ◽  
Formalin Fixed Tissue ◽  
Cell Staining ◽  
Cell Expression ◽  
Disease Free ◽  
Formalin Fixed

AbstractComprehensive studies on the distribution of the Kv1 subfamily have been performed in rat (Chung et al., 2001) and gerbil (Chung et al., 2005), but not in mouse or human. We hypothesized that species differences may exist in the localization of these proteins. Two sets of polyclonal antibodies to Kv1.1-6 were used. Immunohistochemistry was performed on archived, formalin-fixed tissue from disease-free human, monkey and mouse cerebellum. Mouse staining corresponded to that described in rat and gerbil, with strong Kv1.1 and Kv1.2 immunoreactivities in the basket cell pinceau at the base of Purkinje cells. Kv1.3, Kv1.4, Kv1.5 and Kv1.6 were predominantly expressed in Purkinje cells. Human and monkey samples showed a similar pattern to mouse for Kv1.1, Kv1.2, Kv1.3 and Kv1.5. However, little or no Purkinje cell staining was seen in the primates with Kv1.4 and Kv1.6, and strong stellate cell expression was noted. All staining was abolished by cognate peptide blocking. Similar distributions were seen with both sets of antibodies. We conclude that there are marked species differences in the distribution of Kv1.4 and Kv1.6 between primates and rodents. Choosing appropriate animal models for studying physiological and disease processes may prove vital for translating research outcomes into clinical applications.

scholarly journals Hydraulic resistance of perivascular spaces in the brain

2019 ◽  
Author(s):  
Jeffrey Tithof ◽  
Douglas H. Kelley ◽  
Humberto Mestre ◽  
Maiken Nedergaard ◽  
John H. Thomas
Keyword(s):  
Cerebrospinal Fluid ◽  
Blood Vessels ◽  
Hydraulic Resistance ◽  
Perivascular Spaces ◽  
Navier Stokes Equation ◽  
Pial Arteries ◽  
Cross Sectional ◽  
Annular Channels ◽  
The Brain

AbstractBackgroundPerivascular spaces (PVSs) are annular channels that surround blood vessels and carry cerebrospinal fluid through the brain, sweeping away metabolic waste. In vivo observations reveal that they are not concentric, circular annuli, however: the outer boundaries are often oblate, and the blood vessels that form the inner boundaries are often offset from the central axis.MethodsWe model PVS cross-sections as circles surrounded by ellipses and vary the radii of the circles, major and minor axes of the ellipses, and two-dimensional eccentricities of the circles with respect to the ellipses. For each shape, we solve the governing Navier-Stokes equation to determine the velocity profile for steady laminar flow and then compute the corresponding hydraulic resistance.ResultsWe find that the observed shapes of PVSs have lower hydraulic resistance than concentric, circular annuli of the same size, and therefore allow faster, more efficient flow of cerebrospinal fluid. We find that the minimum hydraulic resistance (and therefore maximum flow rate) for a given PVS cross-sectional area occurs when the ellipse is elongated and intersects the circle, dividing the PVS into two lobes, as is common around pial arteries. We also find that if both the inner and outer boundaries are nearly circular, the minimum hydraulic resistance occurs when the eccentricity is large, as is common around penetrating arteries.ConclusionsThe concentric circular annulus assumed in recent studies is not a good model of the shape of actual PVSs observed in vivo, and it greatly overestimates the hydraulic resistance of the PVS. Our parameterization can be used to incorporate more realistic resistances into hydraulic network models of flow of cerebrospinal fluid in the brain. Our results demonstrate that actual shapes observed in vivo are nearly optimal, in the sense of offering the least hydraulic resistance. This optimization may well represent an evolutionary adaptation that maximizes clearance of metabolic waste from the brain.

Abstract P342: Histopathological Correlates of MRI-Visible Perivascular Spaces in Cerebral Amyloid Angiopathy

Stroke ◽  
2021 ◽  
Vol 52 (Suppl_1) ◽  
Author(s):  
Valentina Perosa ◽  
Leon P Munting ◽  
Whitney Freeze ◽  
Ashley A Scherlek ◽  
Anand Viswanathan ◽  
...  
Keyword(s):  
Blood Vessels ◽  
Cerebral Amyloid Angiopathy ◽  
Ex Vivo ◽  
Histopathological Examination ◽  
Amyloid Β ◽  
Amyloid Angiopathy ◽  
Perivascular Spaces ◽  
Cerebral Amyloid

Perivascular spaces (PVS) are fluid-filled spaces surrounding cerebral blood vessels. MRI-visible, supposedly enlarged, PVS in the centrum semiovale (CSO) have been associated with cerebral amyloid angiopathy (CAA). PVS enlargement may be due to perivascular clearance impairments, potentially caused by increased amyloid-β (Aβ) accumulation in the walls of vessels in the overlying cortex. We test this hypothesis, using MRI-guided histopathological examination of PVS in CAA autopsy cases. The cohort included 19 CAA (74.1±8.2y, 7F) and 5 non-CAA control cases (88.0±4.9y, 3F). Formalin-fixed hemispheres were scanned on a 3T MRI scanner, including a 500μm T2-weighted sequence. PVS enlargement was assessed in the CSO on in vivo and ex vivo MRI. In addition, local score of PVS enlargement was assessed in four pre-defined juxtacortical areas (Fig.A), using a semiquantitative score and on the corresponding histological sections (Fig.B). Severity of leptomeningeal and cortical CAA were assessed on adjacent Aβ-stained sections, using a semiquantitative scale.PVS enlargement was more severe in CAA cases compared to controls, both on in vivo and ex vivo MRI (p<0.05). PVS enlargement on ex vivo MRI positively correlated with the severity of PVS enlargement on the corresponding histopathological samples (Fig.C). Within CAA cases, the degree of PVS enlargement on ex vivo MRI was positively associated with leptomeningeal CAA severity (n=52 samples, ρ=0.35, p=0.011), but not cortical CAA severity (n=52 samples, ρ=0.10, p=0.472). These preliminary findings confirm that the degree of MRI-visible PVS in juxtacortical brain areas reflects enlargement on histopathology. Moreover, they suggest that PVS enlargement in cases with CAA corresponds to increased CAA severity in the overlying leptomeningeal vessels, possibly as a result of impaired perivascular clearance. Future directions include characterization of individual blood vessels associated with PVS enlargement.

Musculoskeletal system

2021 ◽  
pp. 281-372
Keyword(s):  
Connective Tissue ◽  
Blood Vessels ◽  
Musculoskeletal System ◽  
Lower Limbs ◽  
Joint Disease ◽  
Muscular Dystrophies ◽  
Arthritic Joint ◽  
System P ◽  
Anatomical Arrangement

The chapter entitled ‘Musculoskeletal system’ summarizes the parts of the connective and skeletal tissues—connective tissue, cartilage, and bone—before looking in more detail at the anatomy of the upper and lower limbs and the spine, including the bones, joints, muscles, innervation, and blood vessels. The chapter provides comprehensive summaries of the bones of the skeleton, their function and anatomical arrangement as well as the muscles involved in movements of different joints and their innervation and anatomical arrangement. The pathology of the musculoskeletal system is discussed, including arthritic joint disease, muscular dystrophies, and atrophy due to disuse.

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