Scanning electron microscopic study of lymphatic corrosion casts in the rabbit appendix

Lymphatic corrosion casts in rabbit ileum: scanning electronmicroscopic studies

AIM

To investigate the three-dimensional organization and fine distribution of the lymphatics in rabbit ileum.

METHODS

Lymphatic corrosion cast with the Mercox were used for scanning electron microscopy (SEM), and semithin sections were used for light microscopy. The Mercox injected intraparenchymally into ileum wall were cut and put in a concentrated NaOH solution until the tissues were corroded away, and observed under SEM.

RESULTS

The central lacteals were found in the intestinal villi. The villi of the ileum contained two to three lacteals. The central lacteals were drained into the mucosal lymphatic capillary plexus. From the plexus, the lymphatic capillary descended into the lymphatics of submucosal layer and muscular layer. Then they were led into the serosal lymphatics and drained into the lymphatics of intestine mesentery. The cast of the lymphatics showed an appearance of a string of heads and the notch corresponding to the bicuspid valve of the lymphatics.

CONCLUSION

The three-dimensional organization of central lacteals and lymphatics in the rabbit ileum is demonstrated by lymphatic corrosion casts. Numerous impressions of the endothelial nuclei, rich central lacteals and lymphatic capillary plexus in the ileum mucosa, lymphatic capillary and lymphatics in the submucosa and muscular layer are observed on the lymphatic corrosion cast.

Pathogenic and pathological characteristic of new type gosling viral enteritis first observed in China

AIM: To study the purifying method and characteristics of new gosling viral enteritis virus (NGVEV), the etiological agent of new gosling viral enteritis (NGVE) which was first recognized in China, as well as the pathomorphological development in goslings infected artificially with NGVEV.

METHODS: ① NGVEV virions were purified by the procedure of treatment with chloroform and ammonium sulfate precipitation, dialysis to remove the sulfate radical and ammonium ion and separation by gel filtration chromatography, and SDS-PAGE. ② Forty 2-day-old White Sichuan goslings were orally administered with NGVEV and 24 h later 2 birds were randomly selected and killed at 24 h intervals until death occurred. Specimens (duodenum, ileum, liver, heart, kidney, spleen, lung, proventriculus, pancreas, esophagus, and the intestinal embolus) were taken until all birds in this group died and were sectioned and stained with hemotoxylin and eosin and studied by light microscope.

RESULTS: NGVEV shared the typical characteristics of Adenovirus and which structural proteins consisted of 15 polypeptides. Necrosis and sloughing of the epithelial cells covering the villus tips of the duodenum were first observed in goslings 2 d postinfection artificially with NGVEV. With the progress of infection, this lesion rapidly occurred in the epithelium at the base of the villus and with infiltration of the inflammatory cells, the jejunum tended to be involved. With the intensification of mucosa necrosis and inflammatory exudation of the small intestine, fibrinonecrotic enteritis was further developed and embolus composed of either intestinal contents wrapped by pseudomembrane or of the mixture of fibrous exudate and necrotic intestinal mucosa were observed in the middle-lower part of the small intestine. This structure occluded the intestinal tract and made the intestine dilated in appearance. The intestinal glandular cells underwent degeneration, necrosis and might be found sloughed into the lumen. Hemorrhage and hyperemia could be observed on the lung and kidney. Epithelial cells of the renal tubular underwent degeneration. In some cases, granular degeneration and fatty degeneration could be found in the liver and in some cases at a later stage of this disease the epithelial cells of trachea and proventriculus might be found sloughed. In some cases at an early stage of this disease, cardiac hyperemia and hemorrhage could be observed. Esophagus, pancreas and brain were found normal. Analyses and comparisons between the pathologic lesions of NGVE and Gosling Plague (GP) were available in this paper as well.

CONCLUSION: ① NGVEV is adenovirus. ② Pathological characteristic could be as the data for NGVE diagnosis.