Histological, histochemical, ultrastructural and immunohistochemical identification and characterization of the neurosecretory cells of the adult rabbit's adrenal medulla.

The present investigation was conducted on the adrenal glands of 40 adult New Zealand rabbits of both sexes to characterize and identify the histological, histochemical, ultrastructural, and immunohistochemical features of the neurosecretory cells of the adrenal medulla. The obtained specimens of adrenal medulla were subjected to routine histological techniques and then stained with different histological stains, including general, non-specific, specific, and highly specific stains for neurosecretory cells, in addition to immunohistochemical reactions. The obtained results showed two types of adrenal medullary neurosecretory cells containing secretory granules (SGs) of different electron densities: adrenaline and noradrenaline (NA) secreting cells. These secretory granules showed a strong positive reaction to the Grimelius silver impregnation technique. Sections stained with Gomori's chrome alum haematoxylin stain, and the secretory granules showed a strong dark blackish-blue positive colour. The medullary cells showed typical chromaffin reactions when stained by H&E and Giemsa stains after formol dichromate 'Ortha's fluid' fixation. The noradrenaline secretory granules gave a strong positive Schmorl's test, while the adrenaline ones showed a moderate reaction. Immunohistochemically, the adrenal medullary cells were subjected to anti-chromogranin A (CHGA) antibody using the PAP technique, which gave positive reactions.

Histomorphological, histochemical and scanning electron microscopic investigation of the proventriculus (Ventriculus glandularis) of the hooded crow (Corvus cornix).

The current investigation aimed to clarify the histomorphological features, scanning electron microscopy (SEM) and histochemistry of the proventriculus in the adult hooded crow (Corvus cornix). Twenty-two adult birds of both sexes were collected from El-Fayoum and Beni-Suef governorates, Egypt; ten were used for anatomical investigation, two were scanned using SEM, and ten were subjected to routine histological technique. The obtained anatomical results revealed a small-sized spindle-shaped proventriculus obliquely located in the left ventral part of the body cavity with an average body weight, length and diameter of 1.689 ± 0.231 gm, 1.54 ± 0.383cm and 3.51 ± 0.416cm, respectively. The histological examination revealed a typical tubular organ. The mucosa exhibited several plicae and sulci that were lined with simple columnar cells. The lamina propria was composed of collagenous connective tissue infiltrated by lymphocytes, lymphatic aggregations and tubular glands. The submucosa consisted of collagenic fibres and compound tubuloalveolar glandular lobules lined with oxynticopeptic cells and enteroendocrine cells. The oxynticopeptic cells reacted negatively with PAS and Alcian Blue stains, whereas the ductal cells reacted positively with PAS only. Enteroendocrine cells were seen singly in the lamina epithelialis mucosae and were abundant in submucosal glands. The tunica musclaris was arranged in two layers covered by serosa. The proventricular glands' openings were noticed by SEM as raised tubes with regular circular outlines surrounded by anastomosed microscopic folds. The obtained histomorphological structure of the hooded crow's proventriculus revealed some shared morphological features with most species of birds and some variations that might be attributed to their diet and feeding behaviour.

Histomorphological, ultrastructural and morphometrical age-related changes of fundic region of New Zealand rabbits (Oryctolagus cuniculus).

This study investigated the histomorphological, ultrastructural and morphometrical postnatal developmental changes in the rabbit fundic region, especially during changing of the feeding intake. Seventy-two New Zealand rabbits (V-Line breed) at the ages of 1, 7, 15, 23, 30 and 60 days were obtained for light and electron microscopy and morphometric studies of the fundic region. The newborn rabbit's fundic wall was thin and organized into mucosa, submucosa, musclosa and serosa, with a significant increase in thickness with ageing. The fundic glands were few at the first week of life, then increased in length and diameter compared to the preceding age with prominent zonation at 23 days. The gastric pits appeared wide and deep at the first week of life then became typically narrow and shallow at the third week. The mucous cells were the main cell types lining the fundic glands in the first week of life. These cells showed remoulding with a marked increase in Periodic Acid-Schiff reactivity with age. Parietal cells were differentiated earlier (on the first day of life) than the chief cells and distributed at the neck and basal zones. Chief cells differentiated at 15 days old at the base of the glands, followed by an increase in the number and activity. Few active enteroendocrine cells were first seen at 15 days old and then widely distributed throughout the glands. Conclusion: Pronounced histomorphological changes in the fundic mucosal layer, especially the surface and glandular epithelium, correlate with the postnatal rabbit-feeding intake changes.

Histomorphological, histochemical, and ultrastructural studies on the stomach of the adult African catfish (Clarias gariepinus).

This study investigated the morphology, histochemistry, and ultrastructure of the adult African catfish (Clarias gariepinus) stomach in order to detect the functional aspects involved in gross and histological studies to get detailed information about the precise cellular structures of different cells lining the stomach. Forty fishes were used in this study. The stomach is a J-shaped sac divided into three regions: (1) cardiac; (2) fundic; and (3) pyloric. Histologically, its wall is composed of four tunics: (1) mucosa; (2) submucosa; (3) muscularis externa; and (4) serosa. The mucosa of the three portions showed thick longitudinal folds lined with simple high columnar cells containing oval basally located nuclei. These cells contained apically located mucosubstances that reacted positively with Periodic-acid Schiff and negatively with Alcian blue stains. Many gastric pits were formed by invaginations of the mucosal layer into the underlying lamina propria and continuous with the openings of the gastric glands. Only the cardiac and fundic regions contained mucosal glands. The fundic glands were lined with oxynticopeptic cells. Enteroendocrine cells were distributed in the gastric wall within the epithelial cells of the gastric mucosa and gland. The lamina propria composed of extensive collagen fibers, many blood vessels, and nerves. Strands of smooth muscle fibers situated between the lamina propria and the submucosa forming lamina muscularis mucosa. Loose connective tissue was the main component of the tunica submucosa. The pyloric portion had the thickest musclosa and the serosal coat of the stomach was formed of loose connective tissue containing blood vessels.