Functional and morphological studies of the primate outflow apparatus

The present investigation of the primate outflow apparatus comprises of two parts. Part I is concerned with the physiological and morphological effects of hyaluronidase on the outflow apparatus of the pig tailed macaque. Part II is a study of age-related changes in the human outflow apparatus. The aim of the first part of the investigation was to discover whether glycosaminoglycans in the trabecular meshwork, particularly the cribriform layer, contributed towards the resistance to aqueous outflow through this pathway. Nine pig tailed macaques (Macaca nemestrina) received an intracameral injection of 300 I.U. of testicular hyaluronidase (in 100 mul of Barany' s fluid) in one eye and the fellow eye served as a control, receiving Barany's fluid alone. One hour after the injections the flow rates at 18 mm Hg and 22 mm Hg from a perfusion system were determined in order to calculate outflow facility. The eyes were perfuse fixed in situ at 18 mm Hg, half an hour after the physiological determinations. Four eyes, two controls and two experimentals, were excluded from the study due to manipulative failures during the experiment. There was a great deal of variation in the results between animals. Despite this it was found that the flow rates in the hyaluronidase-treated eyes were significantly greater than the controls in three of five pairs at 18 mm Hg and in all five pairs at 22 mm Hg. Due to the variation between animals the group results did not prove to be statistically significant. There was no gross morphological difference between control and hyaluronidase-treated eyes, with the exception of slightly greater distension and fewer 'giant vacuoles' in the enzyme treated eyes. The outflow apparatus in both groups of eyes showed marked alterations in configuration compared with the normal unperfused tissue. These changes included rounding up of trabecular endothelial cells; disruption of the cribriform layer; "blow-outs" or focal ballooning of the lining endothelium of Schlemm's canal and herniation of cribriform tissue into collector channel openings. These changes were more severe than would have been predicted on the basis of pressure effects alone and may in fact have been due to physiological manipulation and over perfusion with mock aqueous. In Part II, a wide age range of human eyes, which had been immerse fixed after enucleation in the treatment of various ocular and orbital disorders of the posterior pole, were morphologically investigated. There was a great deal of variation in the morphological appearance of the outflow tissues not only between eyes of similar ages but also within one eye. Despite the variation, several age-related changes were qualitatively and quantitatively described. These included : the thickening of the trabeculae due to increased deposition of connective tissue elements; the trabeculae in older eyes often appeared denuded of their cell cover which seemed to cause focal degeneration and the release of connective tissue materials which appeared to accumulate in the outer meshwork; there was an increase with age in the electron dense plaques in the cribriform layer and a decrease in the ground substance; 'giant vacuoles' in the lining endothelium of Schlemm's canal were rare in older eyes (over 50 years); the incidence of localised canal closure due to apposition of the inner and outer walls was greater in older eyes. The present study of age-related changes in the human outflow apparatus will hopefully contribute to future morphological studies of the outflow apparatus from patients suffering from primary open angle glaucoma

Where are we? : The anatomy of the murine cortical meninges revisited for intravital imaging, immunology, and clearance of waste from the brain

Rapid progress is being made in understanding the roles of the cerebral meninges in the maintenance of normal brain function, in immune surveillance, and as a site of disease. Most basic research on the meninges and the neural brain is now done on mice, major attractions being the availability of reporter mice with fluorescent cells, and of a huge range of antibodies useful for immunocytochemistry and the characterization of isolated cells. In addition, two-photon microscopy through the unperforated calvaria allows intravital imaging of the undisturbed meninges with sub-micron resolution. The anatomy of the dorsal meninges of the mouse (and, indeed, of all mammals) differs considerably from that shown in many published diagrams: over cortical convexities, the outer layer, the dura, is usually thicker than the inner layer, the leptomeninx, and both layers are richly vascularized and innervated, and communicate with the lymphatic system. A membrane barrier separates them and, in disease, inflammation can be localized to one layer or the other, so experimentalists must be able to identify the compartment they are studying. Here, we present current knowledge of the functional anatomy of the meninges, particularly as it appears in intravital imaging, and review their role as a gateway between the brain, blood, and lymphatics, drawing on information that is scattered among works on different pathologies

Alpenloopings in Heimatklänge : Jodeln als Globalisierungsbewegung zwischen Tradition und Experiment

The subject of my contribution is the functioning and effect of yodeling as an experimental form of vocals and singing as presented in Stefan Schwieterts documentary Heimatklänge [Sounds of home] (CH/D 2007); a recursive figure that co-constitutes what is identified as home and forges a sense of identity. Yodeling enables two home »loops« of a special kind: first, the recursive calling-singing in the Swiss Alps, which returns to inside the body as a result of a specific geographic location and its echo, and second, a worldwide sounds network, which through the art of the three Swiss vocal artists Erika Stucky, Noldi Alder, and Christian Zehnder, forms an acoustic bridge from Switzerland via Mongolia to the USA. The essay follows the associative structure of the ilm, which describes a circular movement that seeks to locate the concept of home while alternating in sounds and images between region and global, own and alien, traditional and experimental. With its description of the hypothesis of the origin of yodeling the study begins with a musicological perspective; next, it present an in-depth film analysis of Heimatklänges presentation of yodeling; finally, it formulates a globalization hypothesis in the context of culture studies, which in conjunction with the film endeavours to rethink the relationship between mountain landscape and people

The biology of immune cells in the eye: Implications for development, health and disease

The work presented in this thesis is a collection of papers from research spanning over 25 years. The research commenced whilst the candidate was employed in the Tennent Institute of Ophthalmology and later the Department of Anatomy at the University of Glasgow and continued in the School of Anatomy & Human Biology, The University of Western Australia. The research focuses on the biology of immune cells, primarily dendritic cells (DC), macrophages and mast cells, in the context of various components of the eye, including the aqueous outflow pathways, iris, cornea, ciliary body, choroid and retina, and the supporting tissues (lids and conjunctiva). The studies are broad in the sense that they deal with the role of these cells in development (such as removing the vascular networks around the developing lens), their normal homeostasis and function (distribution, phenotype, turnover and functional activity) and their role in models of a number of eye diseases. The findings are important in understanding the pathogenesis of diseases including bacterial keratitis, anterior uveitis, autoimmune uveoretinitis (endogenous posterior uveitis), toxoplasmic retinochoroiditis, age-related macular degeneration and ocular allergic responses, namely any ocular disease with an immune-mediated pathology. Many of the findings in the enclosed papers were firsts in the field and have shaped our understanding of ocular inflammatory disease. In part the success of some these studies was due to the novel method of performing immunostaining on tissue wholemounts dissected from small rodent eyes. These preparations provided unique ‘plan’ views of the complex networks of DCs and macrophages in the iris and choroid which previously had not been appreciated. In addition, the wholemount approach used in the characterisation and study of immune cells in delicate eye tissues, were applied to related studies of the meninges and choroid plexus of the brain. These studies were amongst the first to fully characterise distinct DC and macrophage networks in the pia, arachnoid, dura and choroid plexus. The research presented in the more recent publications have utilised a range of transgenic, knock-out, congenic and chimeric mouse models to elucidate the function of immune cells in the eye

PG: The monocyte chemokine receptor CX3CR1 does not play a significant role in the pathogenesis of experimental autoimmune uveoretinitis. Invest Ophthalmol Vis Sci 2010

PURPOSE. To examine the role of the monocyte chemokine receptor CX 3 CR1 in experimental autoimmune uveoretinitis (EAU). METHODS. EAU was induced in naive WT, Cx 3 cr1 gfp/ϩ , and Cx 3 cr1 gfp/gfp C57Bl/6 mice or chimeric mice. Ocular disease severity was graded by histologic analysis of resin sections. In addition, immunohistochemistry and confocal microscopy were performed on retinal whole mounts to characterize the monocytic infiltrate and changes in retinal microglia. To determine the relative roles of resident and blood-borne monocytederived cells in the active phase of uveoretinitis, EAU was induced 4 weeks after transplantation in chimeric mice (Cx 3 cr1 gfp/gfp 3 WT and Cx 3 cr1 gfp/ϩ 3 WT), and analysis was performed at days 14, 16, 21, and 28 after immunization. RESULTS. After EAU induction, disease scores were not significantly different in WT, Cx 3 cr1 gfp/ϩ , and Cx 3 cr1 gfp/gfp mice. Chimeric studies revealed both donor-and host-derived monocyte-derived cells in the inner retinal layers during early EAU; however, it was donor monocytic cells that infiltrated the photoreceptors, the site of the target antigen. The absence of CX 3 CR1 did not impede the ability of monocyte-derived cells from Cx 3 cr1 gfp/gfp donor mice to infiltrate during the peak of EAU. CONCLUSIONS. The lack of CX 3 CR1 on monocyte-derived cells does not significantly influence the onset or severity of EAU. In addition, chimeric studies revealed that it is primarily bloodderived monocytes that mediate photoreceptor damage in the effector phase of EAU, and this process is not CX 3 CR1 dependent. (Invest Ophthalmol Vis Sci