Perfusion of particles through arachnoid villi of the monkey

Abstract

By the perfusion of arachnoid villi in excised simian dura mater, the passage through the villi of colloidal gold (.2–.3 µ diam), polystyrene microspheres of 1.17 µ and 1.8 µ, yeast (3–6 µ), goat erythrocytes (4 µ) and monkey erythrocytes (7.5 µ) was demonstrated. Polystyrene microspheres in the 6.4–12.8-µ range were excluded from passage. During the perfusion of the particles an impedance to flow most often developed and the particles were demonstrated by later microscopic examination to be enmeshed in the villi. Upon perfusion of mixtures of various sizes there was not found to be discrimination in passage based on size as long as the particles were beneath threshold size. It is concluded that these observations confirm the surmise, made earlier on anatomical evidence, that the villi provide open communication between the meninges and the venous system.

Cerebrospinal fluid dynamics in the human cranial subarachnoid space: an overlooked mediator of cerebral disease. II. In vitro arachnoid outflow model

“…A second set of experiments using blank culture inserts with both SFM and media with 10 per cent serum showed that the culture inserts with SFM represented a negligible source of resistance when compared with the cellular layer. This linear relationship is consistent with numerous previous studies in both animals and humans (Welch & Pollay 1961;Ekstedt 1978;Czosnyka et al 2004;Lenfeldt et al 2007;Andersson et al 2008). Further characterization of human permeability values under pathological conditions such as increased pressure and with increased loads of cytotoxic proteins is needed.…”

Neuraminidase activity in bacterial meningitis

“…In addition, free NANA may be more rapidly cleared from the subarachnoid space than that which is bound. Free NANA, as a low molecular weight amino sugar, may enter into pathways similar to those responsible for regulation of CSF glucose concentrations (20) whereas bound NANA may be removed largely by bulk flow through arachnoid granulations with other particulate and macromolecular substances (21).…”

Development of hydrocephalus and classical hypothesis of cerebrospinal fluid hydrodynamics: Facts and illusions

“…It is believed that CSF is passively absorbed from the cranial subarachnoid space to the cranial venous blood by means of a hydrostatic gradient (Brodbelt and Stoodley, 2007;Weed, 1935). Welch and coworkers described an open tubular system projecting into the lacuna lateralis or directly into the venous sinus (Welch and Friedman, 1960;Welch and Pollay, 1961).…”