Transmission electron microscopy of human oesophageal carcinomas

Ribosome-lamella complexes in the perineurial cells of neurofibromatosis

Ribosome-lamella complexes are occasionally seen in neoplastic disorders of the hematopoietic system, particularly in hairy cell leukemia. However, these structures are rare in epithelial and mesenchymal cells. In this report three tumors from a patient with neuro-fibromatosis (von Recklinghausen's disease) are examined by electron microscopy. Ribosome-lamella complexes were seen in the perineurial cells. This may be the first report of these complexes in nerve sheath tumors.

The ultrastructure of oesophageal carcinomas: multidirectional differentiation. A transmission electron microscopic study of 43 cases

Forty-three oesophageal carcinomas, comprising 15 squamous cell carcinomas, 22 adenocarcinomas, 5 small cell carcinomas, and 1 adenosquamous carcinoma, were examined by transmission electron microscopy. The ultrastructural features of each tumour type are detailed. Multi-directional differentiation (heterogeneity) was observed in 11 cases: 5 squamous cell carcinomas with focal glandular features; 4 adenocarcinomas with focal squamous features; and 2 small cell carcinomas, one with glandular and the other with squamous features. Abnormal distributions of desmosomes in squamous cell carcinomas and of polarity of tumour cells in adenocarcinomas are described.

Light and electron microscopic and autoradiographic studies on N-methyl-N-amylnitrosamine-induced rat esophageal carcinogenesis

The purpose of this study was to investigate the histogenesis of experimental tumors in the rat esophagus. Thirty rats received 0.0015% N-methyl-N-amylnitrosamine (MNAN) in the drinking water for 12 weeks. Another 30 rats received tap water. All rats then received tap water until sacrifice. Rats from each group were sacrificed immediately after MNAN administration, four weeks after, and eight weeks after. One hour before sacrifice, [3H]TdR was injected by tail vein to label proliferating cells. The entire esophagus and stomach were removed and processed for light and electron microscopy and autoradiography. The overall frequency of esophageal tumors after MNAN was 83% and did not differ significantly among the three experimental groups. Tumors were primarily papillomas and squamous cell carcinomas and occurred with equal frequency in the upper, middle, and lower thirds of the esophagus. No tumors were found in the squamous-lined forestomach. Electron microscopy revealed abundant tonofilaments, free ribosomes, and mitochondria accompanied by vacuoles. By autoradiography, esophageal epithelial proliferation was markedly stimulated in nontumorous mucosa from all three experimental groups. We conclude that MNAN ingestion for 12 weeks reliably produces papillomas and squamous cell carcinomas throughout the rat esophagus, but not in the squamous-lined forestomach, and that MNAN stimulated marked epithelial proliferation which is accompanied by thickening of the epithelium in nontumorous esophageal mucosa.

Junctions between intraepithelial carcinoma and non-neoplastic tissue of the esophagus. Light and electron microscopic studies

This report describes light and electron microscopic observations in 11 patients with intraepithelial carcinomas concomitant with invasive squamous cell carcinomas of the esophagus. The junctions between the intraepithelial carcinomas and non-neoplastic tissues were examined using an electron microscope. Vertical sections through the basal laminae revealed intraepithelial carcinomas with bulky outgrowths and simple replacement histological patterns. The bulky outgrowths contained many pseudopodial cytoplasmic projections from the tumor cells through the basal laminae, while the simple replacement patterns included rare small breaks in the basal laminae. Horizontal sections parallel to the basal laminae showed that the cells of the poorly differentiated squamous cell carcinoma were readily distinguishable from the non-neoplastic cells in the surface layer of the esophageal epithelia and distinctly smaller and darker than the normal prickle cells. At most of the junctions, mesenchymal cells, degenerated cells, and amorphous material separated the tumor cells from the non-neoplastic epithelial cells. However, tumor cells were occasionally attached directly to normal epithelial cells with well-developed desmosomes. Ductal involvement of the carcinomas was found in the submucosal esophageal gland proper. The tumor cells invaded between the ductal cells and basal laminae, and neoplastic cells were also directly attached to the benign ductal cells by poorly-developed desmosomes. The host-tumor junctions in the intraepithelial carcinomas of the human esophagus consisted of basal laminae with hemidesmosomes and pseudopodial projections, mesenchymal cell accumulations and direct attachments with desmosomes.

Are nuclear particles specific for non-A, non-B hepatitis?

This study reports the findings of an electron microscopic search for so-called non-A, non-B nuclear particles in liver biopsies from patients with mainly chronic or prolonged liver disease and from chimpanzees. In patients without hepatitis B virus or acute hepatitis A virus serological markers, non-A, non-B-like nuclear particles were seen in hepatocytes in 28 of 31 cases of presumed non-A, non-B hepatitis, but also in 11 of 12 cases of liver disease not usually attributed to hepatitis viruses. They were also seen in 22 of 24 patients with HBsAg, in 3 of 3 patients with anti-HBc and no HBsAg, in 1 of 2 patients with hepatitis A, in a case of cytomegalovirus hepatitis, and in 16 of 19 patients whose serology was not available or inconclusive. The particles were present in 1 of 8 untreated HBsAg-negative chimpanzees and in 2 of 2 HBsAg-positive chimpanzees. They appeared in 4 of 4 chimpanzees developing non-A, non-B hepatitis following exposure to various inocula. Three patterns of particle aggregates were distinguished, all of which had been shown by others in non-A, non-B hepatitis. Dense aggregates were predominant, while others have shown intermediate aggregates more often; reasons for this difference could be technical. No pattern was specific for any condition. Either non-A, non-B-like nuclear particles, although associated with non-A, non-B hepatitis, are not specific for this condition, or non-A, non-B hepatitis viruses are extremely more common than is currently appreciated.

Ultrastructural features of carcinomas induced in nude mice by the inoculation of human oesophageal carcinoma cell lines

Thirty tumours induced in athymic mice by the inoculation of cells of human oesophageal carcinoma lines were examined by light and transmission electron microscopy, as were 24 cell strains derived from the mouse tumours. All tumours were carcinomas and displayed varying numbers of desmosomes and tonofilaments. Cytoplasmic organelles resembled those in human oesophageal carcinomas in vivo and marker structures such as intranuclear particles persisted in cells grown in nude mice and in vitro. As the nude mouse carcinomas displayed similarities both to one another and to human carcinomas in situ, the nude mouse xenograft system may become a useful model for further studies on tumour biology.