Effects of long-term administration of cancer-promoting substances on oral subepithelial mast cells in the rat.

The role of oral subepithelial mast cells in the defence against tumours is a matter of controversy. The effect of established and suggested carcinogens, such as the carcinogen 4-nitroquinoline-N-oxide (4-NQO) and Herpes simplex virus type 1 (HSV-1), in combination with oral snuff on lower lip subepithelial mast cells (MC) was studied in rats. The rats were exposed to prolonged use of oral snuff. The test substances were administered in a surgically created canal in the lower lip of the rats. There were 15 rats in each test group and 10 rats in the control group. The amount of countable subepithelial mast cells decreased significantly when the rat oral mucosa was exposed to the oral carcinogen 4-NQO but the effect of oral snuff and HSV-1 infection was weak. Our findings suggest that mast cells play a role in immunological cell defence against chemical carcinogens. Further studies are needed to clarify the mechanisms.

A randomized, double-blind, placebo-controlled clinical evaluation of a nicotine sublingual tablet in smoking cessation.

AIMS: Evaluation of the clinical efficacy and safety of a nicotine 2-mg sublingual tablet in smoking cessation. DESIGN: A randomized, double-blind, placebo-controlled study of smokers using the 2-mg tablet for 3-6 months with follow-up to 12 months. Dosing was established according to baseline nicotine dependence, scored on the Fagerström Tolerance Questionnaire (FTQ): FTQ > or = 7, two tablets/hour (maximum 40/day); FTQ < 7, one tablet/hour (maximum 20/day). SETTING: Smoking cessation programme in a department of oral and maxillofacial surgery. PARTICIPANTS: A total of 247 adult smokers, smoking > or = 10 cigarettes/day for > or = 3 years, of whom 123 received active and 124 placebo treatment. The study was powered to detect difference at 6 months. MEASUREMENTS: Efficacy and safety were evaluated at 6 weeks and 3, 6 and 12 months. Self-reported abstinence was verified by exhaled CO < 10 p.p.m. FINDINGS: Success rates for complete abstinence (no slips after 2 weeks) for active vs. placebo were 50% vs. 29% at 6 weeks, 42% vs. 23% at 3 months, 33% vs. 18% at 6 months and 23% vs. 15% at 12 months (p < 0.001, 0.001, 0.005 and p = 0.14), respectively. Craving during the first 8 days was significantly reduced among highly dependent smokers on active treatment compared to placebo. Baseline mucosal lesions among abstinent subjects were reduced during the treatment period and at the non-treatment follow-up. Adverse events were mild and tolerable, the most common being irritation and soreness in the mouth and throat. CONCLUSION: The nicotine sublingual tablet increased the smoking cessation rate compared to placebo, reduced craving in highly dependent smokers and was well tolerated.

Epstein-Barr virus and human papillomavirus in snuff-induced lesions of the oral mucosa.

Epstein-Barr virus (EBV) and human papillomavirus (HPV) have been associated with benign as well as malignant oral lesions. We examined 43 patients with snuff-induced lesions and 22 control patients with clinically healthy oral mucosa for the presence of HPV and EBV. Polymerase chain reaction was performed on fresh frozen oral biopsies with degenerate consensus primers for HPV and nested primers for EBV. None of the 43 snuff-induced lesions or the 22 control biopsies were HPV-positive. Seven of the 43 (16.3%) snuff-induced lesions and one of the 22 (4.5%) controls were positive for EBV. The snuff-induced lesions were classified according to clinical severity, grade 1 lesions being the least severe and grade 4 the most severe. Eleven percent of grade 2 lesions, 15.8% of grade 3 lesions and 20% of grade 4 lesions were EBV-positive. Neither EBV nor HPV seem to be associated with snuff-induced lesions.

The long-term effect of nicotine on the oral mucosa.

AIMS: Although nicotine replacement therapy (NRT) has been used to aid smoking cessation for the last 20 years, little information exists on the effect of nicotine products on the oral mucosa, particularly with regard to the direct effect at the site of application. This study aimed to assess the oral safety of a new sublingual tablet containing 2 mg nicotine with regard to lesions at the site of application. DESIGN: Prospective follow-up to 12 months of smokers using the 2-mg sublingual tablet over a period of 3-6 months. SETTING: A smoking cessation programme. PARTICIPANTS: Thirty smokers. MEASUREMENTS: Oral mucosa was inspected and photographed at each visit. At 6 months, subjects were asked for consent to take a biopsy from the site of application. FINDINGS: Spontaneous smoking cessation outcome at 12 months was 27% allowing for lapses. At baseline 21 mucosal lesions were diagnosed in 15 subjects. After 6 months eight lesions were observed in six subjects. The predominant diagnosis at all visits was melanin pigmentation. Eight subjects had lesions in the floor of the mouth during the 6-month medication period, all of which appeared in the first 1-6 weeks of treatment. By the 6-month visit all such lesions had resolved. The local symptoms were all mild and tolerable. CONCLUSION: The sublingual tablet appears to be a safe form of administration of nicotine with mild and transient effects on the floor of the mouth.

The Swedish snus and the Sudanese toombak: are they different?

In Sweden, snuff (locally known as snus), was introduced since the year 1637. Presently, Sweden has the highest per capita consumption and sale figures of snuff in the world, and the habit is becoming increasingly popular. Snus is manufactured into a dry form used in the nasal cavity and a moist form used in the oral cavity. Snus manufactured for oral use is a moist ground tobacco of Dark Kentucky or Virginia species mixed with an aqueous solution of water and other blending ingredients. This form of snuff is found in two types: (1) loose and (2) portion-bag-packed. These are the most widely used. The loose moist form (1-2 g a quid) is the most popular type consumed by 73% of the males, followed by the portion-bag-packed form (0.5-1 g a quid), consumed by 13% of the males, while 14% of the males are mixed users. The majority of snus users place the quid in the vestibular area of the upper lip, and the prevalence among persons 15 years of age or older in 15.9% among males and 0.2% among females. The pH of snus has declined from a previous range of 8-9 to a range of 7.8-8.5, moisture content ranges 35-60% and nicotine content is in the order of 5-11 mg/g dry wt tobacco-specific N-nitrosamines (TSNAs) in micrograms (N'-nitrosonornicotine: NNN 5-9; 4-(methyl-nitrosamino)-1-(3-pyridyl)-1-butanone: NNK 1-2; N'-nitrosoanatabine: NAT 2-5). In the Sudan, snuff, locally known as toombak, was introduced approximately 400 years ago. It is always processed into a loose moist form, and its use is widespread in the country. Tobacco used for manufacture of toombak is of the species Nicotiana rustica, and the fermented ground powder is mixed with an aqueous solution of sodium bicarbonate. The resultant product is moist, with a strong aroma, highly addictive and its use is widespread particularly among males. Its pH range is 8-11, moisture content ranges 6-60% and nicotine content is from 8 to 102 mg/g dry wt, and TSNAs contents in micrograms (NNN 420-1 550; NNK 620-7 870; NAT 20-290). Snus and toombak dippers develop a clinically and histologically characteristic lesion at the site of dipping. Probably due to control of the TSNAs in snus, this type of snuff is associated with a lower risk of cancer of the oral cavity (relative risk: RR 5-6-fold), whereas the risk for cancer of the oral cavity among toombak users was high (RR 7.3-73.0-fold). In conclusion, the two snuff products significantly differ in many aspects. Most notable differences are tobacco species, fermentation and ageing, nicotine and TSNAs content, pH, expression of the p53 tumour suppressor gene, and keratin types 13, 14, and 19. It was, therefore, the object of the present study to highlight the oral health hazards of toombak, and to compare it with snus regarding the aforementioned differences.

Immunotoxic effects of smokeless tobacco on the accessory cell function of rat oral epithelium.

Smokeless tobacco (ST) is known to adversely effect the oral mucosa, but knowledge about the influence on immune defence is limited. Few studies have investigated the effect of ST on the local immune response. In the present study, we have assessed the effect of a crude Swedish moist snuff (SS) extract, alkaloids, and nitrosamines on T-cell mitogenic response to Con A using epithelial cells, including Langerhans cells, of the rat oral mucosa as accessory cells. SS extract at a concentration of 4% reduced the T-cell proliferation by 50% (IC50 = 4%). Pretreatment of either oral epithelial cells or T-cells with SS extract also gave a significant inhibition of T-cell proliferation. This effect was not obtained following preincubation with SS components as alkaloids and different tobacco-specific nitrosamines (TSNA). None of the tested compounds were found to possess any mitogenic properties. This in vitro study showed that SS extract can evoke an immunosuppressive effect on mitogen-driven T-cell proliferation using cells from oral epithelium as accessory cells. This effect was more pronounced when SS extract was employed compared to when the single SS components were used alone.

Human papilloma virus in erosive oral lichen planus.

Several types of human papilloma viruses (HPV) have been associated with benign and malignant squamous cell tumours of mucosal epithelium. To identify HPV in erosive oral lichen planus (OLPe), considered as a premalignant lesion, tissues from 20 patients were examined by Southern blot hybridization with 32P-labeled HPV DNA probes. Type 11 was found in 6 of the lesions while HPV types 6, 16 and 18 were not detected in any of the tissues examined. Using a type-specific polymerase chain reaction (PCR) assay for HPV-6, 11, 16 and 18, HPV-11 was detected in 8 of the samples (all of those positive by Southern blot), and, in addition, HPV-6 was found in 5 samples and HPV-16 in 3 samples. Overall, by the more sensitive PCR assay, 65% of samples were positive for HPV DNA. The finding of HPV DNA in many of the samples using two different techniques indicates a high prevalence of HPV in the OLPe afflicted oral mucosa. However, the role of HPV in the pathogenesis of OLPe has yet to be determined.