The pathology of 21 cases of muco-epidermoid carcinoma of the anal canal is described. These tumours are defined as squamous or transitional cell carcinomas containing areas which secrete mucin of undoubted epithelial origin within the clumps of tumour cells. They are found in that part of the anal canal just above the dentate line where the epithelium is variable in type and represents an embr...

hemorrhoidectomy is the treatment of choice for patients with third or fourth-degree hemorrhoids. although the majority of surgeons believe that surgical hemorrhoidectomy is the most effective approach with excellent results in the management of hemorrhoid disease, but hemorrhoidectomy is not a simple procedure. one of the complications of this surgery is an injury to anal sphincters that can l...

A retinal ganglion cell receptive field is made up of an excitatory center and an inhibitory surround. The surround has two components: one driven by horizontal cells at the first synaptic layer and one driven by amacrine cells at the second synaptic layer. Here we characterized how amacrine cells inhibit the center response of on- and off-center Y-type ganglion cells in the in vitro guinea pig...

AIMS To determine whether parasol retinal ganglion cells (magnocellular pathway) are selectively lost in the primate model of glaucoma. METHODS Ocular hypertension was induced in one eye of six Macaca fascicularis monkeys for 6-14 weeks. The retinal ganglion cells in these eyes were labelled retrogradely with the tracer horseradish peroxidase (HRP) implanted into the optic nerve and subsequen...

The vertebrate retina has a very high dynamic range. This is due to the concerted action of its diverse cell types. Ganglion cells, which are the output cells of the retina, have to preserve this high dynamic range to convey it to higher brain areas. Experimental evidence shows that the firing response of ganglion cells is strongly correlated with their total dendritic area and only weakly corr...

AIM To evaluate the usefulness of counting nucleolar organiser region associated proteins (AgNORs) in the management of anal squamous neoplasia. METHOD Using a silver staining technique for NOR associated proteins, 32 routinely processed paraffin wax embedded sections of anal epithelium were assessed. These consisted of normal anal epithelium (n = 9), anal intraepithelial neoplasia (AIN) grad...

Diurnal platyrrhines, both di- and trichromats, have magnocellular (M-) and parvocellular (P-) retinal ganglion cells which are morphologically very similar to those found in catarrhines. Catarrhine central P ganglion cells contact single midget bipolar cells, which contact single cones. Physiological recordings of retinal ganglion cells of dichromatic Cebus monkeys showed very similar cell pro...

Visual signals converge through the layers of the retinal circuitry from the photoreceptor cells to the retinal ganglion cells such that nearby ganglion cells are driven by essentially the same visual stimulus. We use computational modeling to address the question whether the experimentally observed degree of synchrony in nearby ganglion cells is due to the common visual stimulus or whether act...

Impairment of visual function has been detected in the early stage of diabetes but the underlying neural mechanisms involved are largely unknown. Morphological and functional alterations of retinal ganglion cells, the final output neurons of the vertebrate retina, are thought to be the major cause of visual defects in diabetes but direct evidence to support this notion is limited. In this study...

Mammalian retinas contain about 20 types of ganglion cells that respond to different aspects of the visual scene, including the direction of motion of objects in the visual field. The rabbit retina has long been thought to contain two distinct types of directionally selective (DS) ganglion cell: a bistratified ON-OFF DS ganglion cell that responds to onset and termination of light, and an ON DS...