Toluene diisocyanate exposure induces laryngo-tracheal eosinophilia, which can be ameliorated by supplementation with antioxidant vitamins in guinea pigs.

OBJECTIVE: Toluene diisocyanate (TDI)-induced asthma is a common cause of occupational lung disease. In addition, a sore throat is one of the complaints of TDI-exposed workers. The aim of the present study was to determine whether TDI exposure induces laryngeal and/or tracheal lesions in experimental animals. MATERIAL AND METHODS: Guinea pigs underwent naris application of TDI three times, and their respiratory tracts were then examined using light and electron microscopy. Some animals simultaneously received vitamins C and E. which function as antioxidant agents. RESULTS: When TDI-treated animals showed the clinical sign of labored breathing, many eosinophils had appeared in the lamina propria and mucosa of both the larynx and trachea, which finally infiltrated the tract lumen through the ruptured epithelium. Laryngo-tracheal inflammation was more severe than that observed in the lungs. However, supplementation with antioxidant vitamins in TDI-treated animals ameliorated the respiratory eosinophilia. CONCLUSION: Naris application of TDI induced laryngotracheitis. which was significantly suppressed by the antioxidant vitamins, This implies a preventive effect of the vitamins on this occupational disease.

An experimental model of multistep laryngeal carcinogenesis: combined effect of human papillomavirus type 16 genome and N-methyl-N'-nitro-N-nitrosoguanidine.

This report describes the two-step in vitro transformation of human laryngeal epithelial cells (HLEC cells). Primary cultured HLEC cells were first transfected with cloned full-length human papillomavirus type 16 DNA, and two immortalized cell lines (HLEC-16 cell lines) were selected by subculturing transfected cells that continued to proliferate. The HLEC-16 cell lines were not tumorigenic in nude mice, and did not proliferate well in a culture medium containing a physiological level of calcium (Dullbecco's minimum essential medium supplemented with 10% fetal bovine serum = DMEM + 10%FBS). The HLEC-16 cell lines were secondarily exposed to N-methyl-N'-nitro-N-nitrosoguanidine, and several proliferating colonies were isolated in DMEM + 10%FBS. Among these calcium/serum-resistant cell colonies, one colony exhibited enhanced proliferation capacity in nude mice. These results support the hypothesis that human laryngeal epithelial cells may be the target for neoplastic transformation by a combined effect of human papillomaviruses and chemical carcinogens.

[Morphohistochemical and electron microscopic characteristics of malignant tumors of the upper respiratory tract after combined local hyperthermia and radiotherapy]. / Morfogistokhimicheskaia i élektronno-mikroskopicheskaia kharakteristika zlokachestvennykh opukholei verkhnikh dykhatel'nykh putei pri sochetanii lokal'noi gipertermii i luchevoi terapii.

The paper discusses morphohistochemical and electron microscopic characteristics of 15 primary tumors of the upper respiratory tract removed following preoperative irradiation in combination with local hyperthermia as a radio-modifying factor. Eighteen tumors removed after irradiation alone served as controls. Application of local microwave hyperthermia resulted in a higher degree of irreversible tumor cell dystrophia and damage. Hyperthermia--induced damage included disorders in ultrastructure of intracellular membranes and cell organelles mainly due to derangement of membrane--binding proteins, protein--lipid and nucleotide complexes. Thermoradiotherapy stimulated protective reaction of surrounding tissue which took the form of increase in fraction of leukocytes and macrophages with high acid phosphatase level in areas of tumor cell damage.