Regional specialisation of the ganglion cell density in the retina of the native duck (Anas platyrhynchos) of Bangladesh.

In this study, retinal whole-mount specimens were prepared and stained with 0.1% cresyl violet for the ganglion cell study in the native duck (Anas platyrhynchos). The total number, distribution and size of these cells were determined in different retinal regions. The mean total number of ganglion cells was 1 598 501. The retinal area centralis had the highest ganglion cell density with 11 200 cells/mm(2) . Number of ganglion cell bodies was the highest in temporal area, followed by dorsal, nasal and ventral areas. Ganglion cell size ranged from 5.25 to 80 µm(2) . In the temporal and nasal region, most of the cells were ranged from 15 to 25 µm(2) , and in the dorsal and ventral region, most of the cells were ranged from 12 to 25 µm(2) . There was a marked trend for the retinal ganglion cell size to increase as the population density decrease towards the periphery. A population of small ganglion cells persisted into the central area just above the optic disc and the largest soma area was in the ventral zone of the retina. Thus, the specialisation of ganglion cell densities and their sizes support the notion that the conduction of visual information towards the brain from all regions of the retina is not uniform, and the central area is the fine quality area for vision in native duck.

A prospective study on histochemical observation of thyroid gland at prepubertal Black Bengal goat.

In the present study, Period Acid Schiff (PAS), Verhoeff's and Van Gieson stains were used in the Department of Anatomy and Histology to observe the histochemical architecture of thyroid gland at prepubertal Black Bengal goat. Thyroid follicular cells were cuboidal in prepubertal goats. These cells showed moderate PAS-positive reaction in prepubertal group. PAS activity in the basement membrane of the thyroid follicles was mild in prepubertal Black Bengal goats. The lumen of the thyroid follicles contained homogenous intense PAS positive colloid materials in prepubertal goats. Parafollicular cells showed intense PAS positive reaction for glycogen in prepubertal goats. Capsule, connective tissue septa, interfollicular connective tissue of the thyroid gland mainly composed of collagen fiber. The wall of blood vessels in the capsule and interfollicular blood capillaries was composed of collagen fiber and elastic fiber. Elastic fiber formed the inner layer of the blood vessels showed blue black to black color. Inner layer of the capsule penetrated the gland parenchyma divided the gland into indistinct lobe and lobules. Collagen fiber distributed around the thyroid follicle formed the interfollicular stroma of the thyroid gland. The results of the present study can also be used to compare with that of human specially in AutoImmune Thyroiditis (AIT).