Localized formation of micronuclei in the oral mucosa and tobacco-specific nitrosamines in the saliva of “reverse” smokers, khaini-tobacco chewers and gudakhu users
✍ Scribed by Hans F. Stich; Bibhuti B. Parida; Klaus D. Brunnemann
- Publisher
- John Wiley and Sons
- Year
- 1992
- Tongue
- French
- Weight
- 642 KB
- Volume
- 50
- Category
- Article
- ISSN
- 0020-7136
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✦ Synopsis
Reverse"-cigar smokers (who hold the burning end of cigars within the mouth), dippers (who place a mixture of Khainitobacco and slaked lime into the lower gingival groove) and users of tobacco-containing toothpaste (gudakhu) in Orissa, India, were examined for precancerous oral lesions, the frequency of micronucleated cells at 3 different intra-oral sites, and levels of tobacco-specific nitrosamines (TSNA) in the saliva. Among reverse-cigar smokers, a high incidence of leukokeratosis nicotina palati, an elevated frequency of micronucleated cells in the palate (2.5% as compared to 0.6% in non-smokers and non-chewers of tobacco) and tongue (2. I YO) from which carcinomas preferentially develop, and up to 5890 ppb nitrosonornicotine and up to 1880 ppb N-nitrosoanatabine in the saliva were found. Among Khaini-tobacco chewers, the frequency of micronucleated cells was elevated to 2. I Yo in the gingival groove, and up to I580 ng N-nitrosonornicotine, 690 ng N-nitrosoanatabine, 90 ng N-nitrosoanabasine, and I80 ng 4-(methyl-N-nitrosamino)-I -(3-pyridyl)-I -butanone) per ml of saliva were observed. The localized elevation of the frequency of micronuclei and cancer development is probably due to a synergistic effect of hyperthermia and tobacco-related carcinogens among reverse-cigar smokers, and to the close, prolonged contact between the mucosa and tobacco among Khaini-tobacco/slaked lime dippers. Neither pre-cancerous lesions nor an elevated frequency of micronuclei were seen in the oral mucosa of users of gudakhu, a tobacco-containing toothpaste, which may be due to the low amount of TSNA released from the gudakhu and the short exposure time, which is restricted to the period of tooth brushing.