Experimental aneurysmatic dilatation of the rabbit common carotid artery was induced by a single, periarterial application of calcium chloride in vivo. Vessels were fixed in situ after 3 d, 1 wk, 3 wk, 6 wk, and 12 wk by intracardiac perfusion of glutaraldehyde and tissues prepared for light, scanning, and transmission electron microscopy. Progressive focal aneurysmal dilatation was seen limited to the site of calcium application with endothelial damage and thrombus formation in areas of irregular luminal contour. Disruption of the elastic network of the intima and media was seen with varying degrees of intimal fibromuscular hyperplasia and medial disorganization.The calcium-elastic tissue complex was the focus of the inflammatory, arteriosclerotic reaction and subsequent aneurysm formation. The inflammatory cell infiltration initially included primarily neutrophils followed by lymphocytes, plasma cells, monocytes, and multinucleated giant cells. These studies support the hypothesis that disruption of the elastic tissue network of the vascular wall represents an important pathogenetic factor in the initiation of aneurysmal dilatation. In addition, the results of these studies suggest that interaction of calcium with the elastica of the arterial wall may represent an important pathogenetic factor in the initiation of giant cell arteritis.

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Latanoprost and unoprostone (isopropyl unoprostone) represent the first commercially available prostaglandin analogues to be used for the treatment of glaucoma. Both compounds reduce intraocular pressure by enhancing uveoscleral outflow. Latanoprost, when used once daily in the evening, produces a greater reduction in pressure than timolol. Latanoprost produces mild conjunctival hyperaemia compared with timolol in some patients. Darkening of the irides has been reported, especially in green-brown, yellow-brown and blue/grey-brown irides. Hypertrichosis and hyperpigmentation of the eyelashes have also been demonstrated. Although latanoprost has not been proven to cause uveitis or cystoid macular oedema, case reports of an association exist. Latanoprost does not produce systemic adverse effects nor does it alter routine blood analyses. Unoprostone, when given twice daily, produces less of a reduction in intraocular pressure than timolol or latanoprost. Three times daily use may be required to approach the effectiveness of timolol. Unoprostone may have a similar adverse effect profile to latanoprost, but may to cause more corneal epithelial problems. Unoprostone is also not known to cause systemic adverse effects. Both agents are welcome additions to the treatment of glaucoma. However, additional studies and more experience are needed with each agents.

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