Chlorhexidine solutions in histological and histochemical techniques 1

The long‐term effect of snuff exposure was studied in Sprague‐Dawley rats using a surgically‐created test canal in the lower lip to retain snuff. The rats received standard snuff (n = 42) and highly alkaline snuff (n = 10) for 9–22 months, whereupon they were killed. Untreated rats with identical test canals (n = 15) served as controls. A complete post‐mortem examination was performed. One rat exposed to standard snuff for 9 months developed a squamous cell carcinoma of the oral cavity. However, exposure to standard snuff usually resulted in a mild to moderate hyperplasia of the epithelium, hyperorthokeratosis and acanthosis. Rats exposed to snuff for 18–22 months showed vacuolated cells penetrating deeper into the epithelium with hyperplastic and atrophic lesions. In a few rats, severe dysplastic changes developed in the crevicular epithelium. Rats exposed to alkaline snuff differed little from the first group except that there was focally atrophic and ulcerated epithelium and less fibrosis. Pathological findings outside the oral cavity were rare. Squamous cell hyperplasia of the forestomach was found in rats exposed to snuff for 18–22 months, possibly caused by ingested snuff. In conclusion, this study has shown that exposure of rats to snuff for 10–16 hours per day 5 days a week for most of their life‐span resulted in lesions mainly restricted to the epithelium and the underlying connective tissue of the surgically created test canal.

Section: Methodsmentioning

confidence: 99%

Effect of long‐term application of snuff on the oral mucosa: an experimental study in the rat

Hirsch

Johansson

1983

“…The seetioning was performed in a eryostat at -20°C. 8 (xm seetions were eut (Heyden et al 1972). The test eanals were seetioned perpendieularly to the longitudinal axis of the eanals at three levels: anterior, central and posterior.…”

Section: Histological Ntethodsmentioning

confidence: 99%

Snuff‐induced lesions of the oral mucosa – an experimental model in the rat

Hirsch

Thilander

1981

An experimental model in the white rat has been developed in order to study the influence of snuff on oral mucosa. A test canal in the lower lip, with one orifice buccally to the incisors and one on the lip side, was created by surgical means. The connection between the canal and the oral cavity was made to ensure the presence of saliva in the canal so that physiological conditions resembling those of the oral cavity were obtained. The canal was filled with snuff morning and night 5 days a week. The mean value for the maximal retention time of the snuff was 6 h. The animals tolerated the dose and time of exposure without signs of severe toxic symptoms. Histological examination of the canals after 9 months of exposure to snuff showed a mildly to moderately hyperplastic epithelium with hyperorthokeratosis. Locally deep proliferations of epithelium with acanthotic rete pegs could be seen. In the stratum basale hyperplasia with disturbed polarity and hyper‐chromatic nuclei and single mitosis were noted.

“…. , Twenty-six of the 52 keratocysts had arrived at the laboratory in ice-cold Histocon® (Heyden et al 1972), The remainder were in either Histocon® at room temperature or in 10% neutral buffered formalin. The Histocon-stored material was mounted on cryostat chucks, frozen in isopentane pre-chilled by liquid nitrogen, and 7 (xm sections were cut in a cryostat (System Dittes-Dusoiva, Heidelberg, Germany).…”

mentioning

confidence: 99%

Odontogenic keratocysts: a clinical and histological study with special reference to enzyme histochemistry

Magnusson

1978

Abstract. Of a total of 1,420 odontogenic cysts, 52 (3.3%) were diagnosed as odontogenic keratocysts. Clinical and histological findings in these 52 cysts are reported. Frozen sections of 26 of the keratocysts were incubated to show the following enzyme activities: NADH2‐ and NADPH2‐diaphorase, glucose‐6‐phosphate dehydrogenase, glutamate dehydrogenase, acid phosphatase, leucine aminopeptidase and ATPase. Furthermore, keratinization was studied with the rhodamine B method and lipids with the oil red O, the OTAN and the acid hematein methods. Sections from epidermis, oral mucosa, radicular cysts, residual cysts and follicular cysts served as reference material. The oxidative enzymes showed strong activity in the keratocyst epithelium which contrasted with weak activity in the reference cysts. Acid phosphatase activity was weak in all epithelia except that in keratocysts, which displayed a marked activity. In the fibrous capsule of the keratocyst a high activity of leucine aminopeptidase was recorded. This high activity contrasted with a weak activity in the reference material. The significance of the histochemical results in relation to the aggressive behavior of the keratocyst is discussed.