Ultrastructural features of the tegument of adult Cynodiplostomum azimi (Trematoda:Digenea) in experimentally infected albino rats.

The ultrastructure of the tegument of adult Cynodiplostomum azimi and the lesions caused by the worm at this host parasite interface in albino rats are described. The tegument consists of a syncytial distal cytoplasm (approx. 2.01-3.1 microns in thickness), bounded by an outer apical plasma membrane and an inner basal trilaminated lamina. The subtegumental cells (approx. 10.34 microns in length) are connected with the distal cytoplasm by means of cytoplasmic trabeculae. The morphology of the tegument appeared very variable. Large areas were formed of irregular folds, while other areas carried finger-like or papilla-form structures. Tegumental spines appear to have a crystalline lattice structure. Three morphologically distinct types of membrane-bound inclusion bodies were described in the tegumental/perikaryal complex. The electron-lucent elongate bodies (approx. 0.23 micron in length) were the predominant first type. The second was round-ovoid bodies (average length 0.12 micron) with a central core of electron-dense material. The third was electron-dense, rod-like in shape (0.28 micron in length) and occurred occasionally. The majority of these inclusion bodies were oriented parallel to the tegumental surface. The host's mucosa at the parasite interface showed marked flattening and partial to complete loss of mucosal microvilli. Inflammatory cells, particularly eosinophils were observed at the host-parasite interface.

Scanning electron microscopy of the small intestine of rats experimentally infected with Cynodiplostomum azimi.

Scanning electron micrographs of the proximal intestine of rats infected with C. azimi showed mild villous changes and excessive mucus secretion as early as the first day after infection. On the second day the regular leaf-like pattern of the villi was not seen, the epithelial lining of the mucosa was damaged with large amounts of mucus. Goblet cell openings appeared either empty or filled with secretions. The mucosal damage persisted for three months. Four months after infection, villi regained part of their normal pattern. Their epithelial lining although less damaged, appeared delicate. Villi away from the worm were less affected. Pathological changes at different intervals of infection were discussed in relation to the surface structure of the parasite.

Some ultrastructural studies on the excretory bladder of the adult Cynodiplostomum azimi (Trematoda: Digenea) in infected rats.

Transmission electron microscope was used to reveal the reserve bladder system of the adult Cynodiplostomum azimi in experimentally infected rats. It was shown that this system consisted of a number of lacunae. The lacunar lining appeared as syncytial epithelium containing many nuclei, mitochondria, dense secretory bodies, Golgi complex and bundles of smooth muscles. The outer surface of the excretory epithelium was highly folded and lamellated. These lamellae were continuous with the excretory epithelium. Small lipid droplets were observed within the excretory epithelium, while larger ones were associated with the lamellae. The large lipid droplets were released in the lacunal lumen after the rupture of the lamellae surrounding them.

Effect of testosterone on the ovotestis of the land snail Theba pisana.

The effect of testosterone on the histological pattern of the gonads of the land snail Theba pisana was studied. It was found that testosterone accelerated spermatogenesis, as indicated by the large increase in the number of spermatozoa and the decrease in the number of primary spermatocytes. The diameter of the acini in treated snails was greater than in the normal controls. Conversely, testosterone led to reduction of the number of mature ova.