The Experts below are selected from a list of 1629 Experts worldwide ranked by ideXlab platform
Dong Zhou - One of the best experts on this subject based on the ideXlab platform.
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Pseudotumor cerebri syndrome and giant Arachnoid Granulation: treatment with venous sinus stenting.
Journal of vascular and interventional radiology : JVIR, 2010Co-Authors: Hongbo Zheng, Muke Zhou, Bi Zhao, Dong ZhouAbstract:The authors describe a patient with pseudotumor cerebri syndrome who showed at venography a giant Arachnoid Granulation in the left dominant transverse sinus and hypoplasia of the contralateral transverse sinus with high pressure proximal to the obstruction. Dilation of the left transverse sinuses with a stent reduced both the pressure gradient across the Arachnoid Granulation and the cerebral spinal fluid opening pressure with immediate symptomatic improvement, suggesting a causal relationship between venous outflow obstruction and pseudotumor cerebri syndrome.
Sabbir H Siddique - One of the best experts on this subject based on the ideXlab platform.
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Cerebrospinal fluid absorption block at the vertex in chronic hydrocephalus: obstructed Arachnoid Granulations or elevated venous pressure?
Fluids and Barriers of the CNS, 2014Co-Authors: Grant A Bateman, Sabbir H SiddiqueAbstract:BackgroundThe lack of absorption of CSF at the vertex in chronic hydrocephalus has been ascribed to an elevation in the Arachnoid Granulation outflow resistance (Rout). The CSF infusion studies measuring Rout are dependent on venous sinus pressure but little is known about the changes in pressure which occur throughout life or with the development of hydrocephalus.MethodsTwenty patients with chronic hydrocephalus underwent MR venography and MR flow quantification techniques. The venous outflow pressure was estimated from the sinus blood flow and the cross-sectional area of the transverse sinuses. Adult controls as well as a normal young cohort were selected to estimate the change in sinus pressure which occurs throughout life and following the development of hydrocephalus. Significance was tested with a Student’s t-test.ResultsThe size of the transverse sinuses was unchanged from the 1st to the 5th decade of life, indicating a stable outflow resistance. However, the blood flow was reduced by 42%, indicating a likely similar reduction in pressure gradient across the sinuses. The sinuses of hydrocephalus patients were 38% smaller than matched controls, indicating a 2.5 times increase in resistance. Despite the 24% reduction in blood flow, a significant increase in sinus pressure is suggested.ConclusionsThe size of the venous sinuses normally does not change over the age range investigated but sinus pressure is reduced proportional to an age-related blood flow reduction. Hydrocephalus is associated with much smaller sinuses than normal and an elevation in venous pressure may explain the lack of CSF absorption into the Arachnoid Granulations in chronic hydrocephalus.
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Cerebrospinal fluid absorption block at the vertex in chronic hydrocephalus: obstructed Arachnoid Granulations or elevated venous pressure?
Fluids and barriers of the CNS, 2014Co-Authors: Grant A Bateman, Sabbir H SiddiqueAbstract:Background The lack of absorption of CSF at the vertex in chronic hydrocephalus has been ascribed to an elevation in the Arachnoid Granulation outflow resistance (Rout). The CSF infusion studies measuring Rout are dependent on venous sinus pressure but little is known about the changes in pressure which occur throughout life or with the development of hydrocephalus.
Hongbo Zheng - One of the best experts on this subject based on the ideXlab platform.
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Pseudotumor cerebri syndrome and giant Arachnoid Granulation: treatment with venous sinus stenting.
Journal of vascular and interventional radiology : JVIR, 2010Co-Authors: Hongbo Zheng, Muke Zhou, Bi Zhao, Dong ZhouAbstract:The authors describe a patient with pseudotumor cerebri syndrome who showed at venography a giant Arachnoid Granulation in the left dominant transverse sinus and hypoplasia of the contralateral transverse sinus with high pressure proximal to the obstruction. Dilation of the left transverse sinuses with a stent reduced both the pressure gradient across the Arachnoid Granulation and the cerebral spinal fluid opening pressure with immediate symptomatic improvement, suggesting a causal relationship between venous outflow obstruction and pseudotumor cerebri syndrome.
Martin Lubow - One of the best experts on this subject based on the ideXlab platform.
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retinol effects on csf outflow through cultured human Arachnoid Granulation cells implications for ptc
Cerebrospinal Fluid Research, 2009Co-Authors: David W Holman, Martin Lubow, Deborah M GrzybowskiAbstract:Background The underlying etiology of pseudotumor cerebri (PTC) remains unknown, however it has been estimated that an identifiable secondary cause is present in up to 10% of PTC cases. Of these secondary associations, vitamin A is of particular interest, as vitamin A toxicity is associated with an increased intracranial pressure similar to that seen in PTC. Recently, several clinical studies have suggested that serum and CSF retinol levels may be altered in PTC. We hypothesize that increased concentrations of retinoids in the CSF might increase resistance to CSF outflow at the Arachnoid Granulations (AGs).
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In Vitro Model of Cerebrospinal Fluid Outflow through
2008Co-Authors: Human Arachnoid Granulations, Deborah M Grzybowski, Steven E Katz, David W Holman, Martin LubowAbstract:PURPOSE. To describe and validate an in vitro model of the Arachnoid Granulation (AG) outflow pathway for cerebrospinal fluid (CSF), by using human AG cells grown on a filter membrane support and perfused in a modified Ussing chamber at pressures analogous to normal human intracranial pressures. METHODS. Human AG cells were grown, characterized, seeded onto filter membranes, and perfused in the physiologic (basal to apical, B3A) or nonphysiologic (apical to basal, A3B) directions. Cells were fixed under pressure after perfusion and prepared for electron microscopy (EM). RESULTS. The average cellular hydraulic conductivity in the B3A direction (10 total) was 4.52 � 0.43 �L/min per mm Hg/cm 2 with an average transcellular pressure decrease of 3.13 � 0.09 mm Hg. The average cellular hydraulic conductivity in the A3B direction (six total) was 0.29 � 0.16 �L/mi
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in vitro model of cerebrospinal fluid outflow through human Arachnoid Granulations
Investigative Ophthalmology & Visual Science, 2006Co-Authors: Deborah M Grzybowski, Steven E Katz, David W Holman, Martin LubowAbstract:PURPOSE. To describe and validate an in vitro model of the Arachnoid Granulation (AG) outflow pathway for cerebrospinal fluid (CSF), by using human AG cells grown on a filter membrane support and perfused in a modified Ussing chamber at pressures analogous to normal human intracranial pressures. METHODS. Human AG cells were grown, characterized, seeded onto filter membranes, and perfused in the physiologic (basal to apical, B3A) or nonphysiologic (apical to basal, A3B) directions. Cells were fixed under pressure after perfusion and prepared for electron microscopy (EM). RESULTS. The average cellular hydraulic conductivity in the B3A direction (10 total) was 4.52 0.43 L/min per mm Hg/cm 2 with an average transcellular pressure decrease of 3.13 0.09 mm Hg. The average cellular hydraulic conductivity in the A3B direction (six total) was 0.29 0.16 L/min per mm Hg/cm 2 with an average transcellular decrease in pressure of 3.33 0.16 mm Hg. Cells perfused nonphysiologically showed a large number of dead and dying cells. EM postperfusion analysis showed that AG cells were integrally attached to the underlying filter membrane. Large extracellular cisternal spaces were visible between overlapping AG cells and vacuoles within the cytoplasm. It is possible that these spaces within and between cells represent pathways for transcellular and paracellular transport of fluid. CONCLUSIONS. The results demonstrate that AG cells in vitro show a statistically significant greater flow rate and cellular hydraulic conductivity when perfused in the physiologic versus the nonphysiologic direction under normal intracranial pressures. These results suggest that this in vitro model of the AGs can accurately replicate the unidirectional flow of CSF in vivo. (Invest Ophthalmol Vis Sci. 2006;47:3664‐3672) DOI:
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characterization of cytoskeletal and junctional proteins expressed by cells cultured from human Arachnoid Granulation tissue
Cerebrospinal Fluid Research, 2005Co-Authors: David W Holman, Deborah M Grzybowski, Steven E Katz, Bhavya C Mehta, Martin LubowAbstract:The Arachnoid Granulations (AGs) are projections of the Arachnoid membrane into the dural venous sinuses. They function, along with the extracranial lymphatics, to circulate the cerebrospinal fluid (CSF) to the systemic venous circulation. Disruption of normal CSF dynamics may result in increased intracranial pressures causing many problems including headaches and visual loss, as in idiopathic intracranial hypertension and hydrocephalus. To study the role of AGs in CSF egress, we have grown cells from human AG tissue in vitro and have characterized their expression of those cytoskeletal and junctional proteins that may function in the regulation of CSF outflow. Human AG tissue was obtained at autopsy, and explanted to cell culture dishes coated with fibronectin. Typically, cells migrated from the explanted tissue after 7–10 days in vitro. Second or third passage cells were seeded onto fibronectin-coated coverslips at confluent densities and grown to confluency for 7–10 days. Arachnoidal cells were tested using immunocytochemical methods for the expression of several common cytoskeletal and junctional proteins. Second and third passage cultures were also labeled with the common endothelial markers CD-31 or VE-cadherin (CD144) and their expression was quantified using flow cytometry analysis. Confluent cultures of Arachnoidal cells expressed the intermediate filament protein vimentin. Cytokeratin intermediate filaments were expressed variably in a subpopulation of cells. The cultures also expressed the junctional proteins connexin43, desmoplakin 1 and 2, E-cadherin, and zonula occludens-1. Flow cytometry analysis indicated that second and third passage cultures failed to express the endothelial cell markers CD31 or VE-cadherin in significant quantities, thereby showing that these cultures did not consist of endothelial cells from the venous sinus wall. To our knowledge, this is the first report of the in vitro culture of Arachnoidal cells grown from human AG tissue. We demonstrated that these cells in vitro continue to express some of the cytoskeletal and junctional proteins characterized previously in human AG tissue, such as proteins involved in the formation of gap junctions, desmosomes, epithelial specific adherens junctions, as well as tight junctions. These junctional proteins in particular may be important in allowing these Arachnoidal cells to regulate CSF outflow.
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Characterization of cytoskeletal and junctional proteins expressed
2005Co-Authors: David W Holman, Deborah M Grzybowski, Steven E Katz, Bhavya C Mehta, Martin Lubow, Open AccessAbstract:by cells cultured from human Arachnoid Granulation tissu
Grant A Bateman - One of the best experts on this subject based on the ideXlab platform.
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the incidence of transverse sinus stenosis in multiple sclerosis further evidence of pulse wave encephalopathy
Multiple sclerosis and related disorders, 2020Co-Authors: Grant A Bateman, Jeannette Lechnerscott, Alexander Robert Bateman, John Attia, Rodney Arthur LeaAbstract:Abstract Background Multiple sclerosis (MS) is associated with a breakdown in the intracranial pulse wave dampening or windkessel effect. This is manifest by an increase in the arterial stroke volume and a decrease in the dampening afforded by both the CSF displaced into the spinal canal and the blood displaced by the venous sinus pulsation. There is evidence that the reduction in compliance of the sagittal and straight sinuses in MS is caused by an increase in venous pressure despite the jugular bulb pressures being normal. This implies MS patients have a venous outflow stenosis somewhere between the torcular and jugular bulbs. The purpose of the current study is to define the site, significance and cause of these stenoses. Methods 50 patients with MS were prospectively recruited from an MS clinic and compared to 50 matched control patients. Using 3DT1 post contrast images, a survey of the venous sinuses was performed looking for the narrowest portion of the sinuses in each of 4 segments from the sagittal sinus to jugular bulbs. The cross sectional areas and wetted circumferences of the venous sinuses were measured at each site to calculate the minimum hydraulic and effective diameters. The BMI, optic nerve sheath diameters and pituitary heights were measured. Statistical analysis was performed using non-parametric methods and was assessed using α≤0.05. Results Compared to controls, the MS patients’ sagittal sinuses were 24% larger in cross-section (p=0.0001) with an 18% larger wetted circumference (p=0.0001). The MS patients’ transverse sinuses had an average effective stenosis of 38% by area (p 65% by area and 16/50 a low grade stenosis of between 40-65% by area compared to 1/50 low grade stenoses in this segment in the controls. The commonest cause of the stenosis was a giant Arachnoid Granulation. The optic nerve sheaths were larger in MS than controls (p=0.0006). Comparing MS patients with transverse sinus stenosis to those without, the pituitary height was 16% smaller and BMI 25% larger (p=0.02 and 0.003 respectively) Conclusion In patients with MS, the reduction in venous sinus compliance is associated with venous outflow stenoses in the transverse sinuses which increases the upstream venous pressure and dilates the sagittal sinuses. This finding suggests a continuum exists between MS and idiopathic intracranial hypertension.
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Cerebrospinal fluid absorption block at the vertex in chronic hydrocephalus: obstructed Arachnoid Granulations or elevated venous pressure?
Fluids and Barriers of the CNS, 2014Co-Authors: Grant A Bateman, Sabbir H SiddiqueAbstract:BackgroundThe lack of absorption of CSF at the vertex in chronic hydrocephalus has been ascribed to an elevation in the Arachnoid Granulation outflow resistance (Rout). The CSF infusion studies measuring Rout are dependent on venous sinus pressure but little is known about the changes in pressure which occur throughout life or with the development of hydrocephalus.MethodsTwenty patients with chronic hydrocephalus underwent MR venography and MR flow quantification techniques. The venous outflow pressure was estimated from the sinus blood flow and the cross-sectional area of the transverse sinuses. Adult controls as well as a normal young cohort were selected to estimate the change in sinus pressure which occurs throughout life and following the development of hydrocephalus. Significance was tested with a Student’s t-test.ResultsThe size of the transverse sinuses was unchanged from the 1st to the 5th decade of life, indicating a stable outflow resistance. However, the blood flow was reduced by 42%, indicating a likely similar reduction in pressure gradient across the sinuses. The sinuses of hydrocephalus patients were 38% smaller than matched controls, indicating a 2.5 times increase in resistance. Despite the 24% reduction in blood flow, a significant increase in sinus pressure is suggested.ConclusionsThe size of the venous sinuses normally does not change over the age range investigated but sinus pressure is reduced proportional to an age-related blood flow reduction. Hydrocephalus is associated with much smaller sinuses than normal and an elevation in venous pressure may explain the lack of CSF absorption into the Arachnoid Granulations in chronic hydrocephalus.
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Cerebrospinal fluid absorption block at the vertex in chronic hydrocephalus: obstructed Arachnoid Granulations or elevated venous pressure?
Fluids and barriers of the CNS, 2014Co-Authors: Grant A Bateman, Sabbir H SiddiqueAbstract:Background The lack of absorption of CSF at the vertex in chronic hydrocephalus has been ascribed to an elevation in the Arachnoid Granulation outflow resistance (Rout). The CSF infusion studies measuring Rout are dependent on venous sinus pressure but little is known about the changes in pressure which occur throughout life or with the development of hydrocephalus.