C.W. van Wyk

A comparative light-microscopic, electron-microscopic and chemical study of human vaginal and buccal epithelium.

The scarcity of sizeable specimens of normal oral mucosa for experimental purposes has hampered research on oral epithelium. Because large specimens of viable human vaginal mucosa are readily available and because vaginal and buccal epithelia are microscopically similar, vaginal mucosa has been used successfully to establish a human cyst model in experimental animals. The ultrastructure and distribution of keratin filaments in these epithelia are also similar, as is their permeability to water and a number of chemical substances. Therefore, if vaginal mucosa could be substituted for buccal mucosa it would expedite research on the epithelium of buccal mucosa. To strengthen further the concept that vaginal epithelium could replace buccal epithelium in certain experimental studies, the thickness of these epithelia, their patterns of surface keratinization, the presence or absence of intercellular lipid lamellae and their lipid contents were now compared. Thirty-three specimens of vaginal mucosa from postmenopausal women and 36 of buccal mucosa were investigated. To compare the thickness of the epithelial layers the number of cell layers in sections of 20 vaginal and 20 buccal mucosal specimens were counted in the three thickest and three thinnest regions of each specimen. Surface keratinization was evaluated on sections stained with the Picro-Mallory method. To demonstrate lipid lamellae two vaginal and two buccal mucosa specimens were examined electron microscopically after normal fixation and postfixation in ruthenium tetroxide. Following solvent extraction of 11 vaginal and 14 buccal epithelia, quantitative lipid analyses were performed using thin-layer chromatography. No statistically significant differences were found between the maximum and minimum number of epithelial cell layers. The patterns of surface keratinization and the distribution and appearance of the lipid lamellae in the intercellular spaces were similar. The lipid composition of the two epithelia corresponded, except for the cholesterol esters and glycosylceramides, which were higher in buccal epithelium. Ceramides for vaginal epithelium and triglycerides for buccal epithelium were not determined. Based on structural similarities, a similar lipid composition and earlier findings, it is concluded that vaginal epithelium can be used as a substitute for buccal epithelium in certain in vitro, and possibly for in vivo, studies.

Bacterial electrode for l-arginine

Streptococcus lactis bacterial cells are employed for the conversion of L-arginine into ammonia. An ammonia gas-electrode is used as a detector. The combination of bacterial action and the gas electrode responds linearly to L-arginine over the concentration range 8.0 x 10(-6) - 1.0 x 10(-3)M, with a slope of 59.0 mV/decade and is selective with respect to other l-amino acids.

Calcium, Phosphorus, Fluoride, and pH Levels of Human Dental Plaque from Areas of Varying Fluoride Levels

Plaque calcium, phosphorus, fluoride, and pH in samples obtained from 149 life-long resident children, aged from six to seven and 12 to 13 yr, from one of three naturally fluoridated communities were determined. In general, smaller amounts of phosphorus and fluoride, and larger amounts of calcium and hydrogen ions (lower pH values) are associated with smaller amounts of fluoride in the drinking water supply. Significant differences among the mean pH, fluoride, and Ca/P concentrations both in the six-to-seven- and 12-to-13-year age group were found when comparing the results of the three areas with different levels of fluoride in their drinking water supply.

Recurrent unicystic ameloblastoma of the maxilla

A previously reported unicystic ameloblastoma, showing luminal plexiform epithelial proliferation and the presence of small islands of odontogenic epithelium in the connective tissue of the cyst wall, recurred 5 years after conservative surgery. The tumour was nucleated and since the epithelial islands were confined to its fibrous capsule a conservative approach was regarded as adequate. In view of the later experience it is now proposed that where cystic ameloblastomas depict epithelial infiltration into the capsule a second excision be considered and that such surgical material be thoroughly examined for signs of epithelial infiltration. Whatever type of treatment the surgeon decides to perform, it is essential to have a long postoperative period of monitoring. Because the presence of islands of odontogenic epithelium in the cyst wall influences the surgical approach, it is recommended that pathologists carefully examine cystic ameloblastoma surgical specimens for their presence. Multiple, even serial sections are required for such examinations. The pathology report should include a description of the islands with an indication of their site in the capsule of the tumour.

Central papillary atrophy of the tongue

Twenty-eight cases of central papillary atrophy of the tongue (CPA) are presented. Vegetative Candida species were commonly but not invariably seen on cytologic and histologic examination. Follow-up of fifteen cases showed spontaneous resolution of three. It is suggested that CPA of the tongue represents a clinical rather than a pathologic entity, and that the underlying disease process may not be identical in all cases.

Primary intraosseous carcinoma involving the anterior mandible

A case is reported of a primary intraosseous carcinoma arising in the anterior mandible with metastasis to the submandibular lymph node in a 69 year-old Caucasian female. The patient initially presented with a burning sensation in the oral cavity in 1983, when no obvious pathological finding was noted; she returned 2 years later with a firm buccal swelling which had increased in size after the extraction of a mobile tooth. The tumour proved to be a primary intraosseous intraosseous carcinoma; extensive investigation did not reveal a primary carcinoma elsewhere.

Oral lesions caused by habits.

Oral lesions caused by habits can be of teeth only, of teeth and the soft tissues of the mouth or may be only of the soft tissues. Lesions of teeth are permanent and may remain even when there has been total destruction of soft tissues. Recognition of lesions due to habits such as betel chewing, snuff dipping, pipe smoking and certain sexual practices may help towards establishing the sex, the ethnic grouping or even the place of origin of a person or their remains. Certain dental and gingival changes may indicate a persons working circumstances and even the type of treatment received.

An experimental cyst model established from human unkeratinized vaginal mucosa

Because of the scarcity of sizeable specimens of normal oral mucosa and the availability of human vaginal mucosa, which resembles the lining mucosa of the mouth, we used the latter to establish a human cyst model. Fragments of vaginal mucosa, removed during corrective procedures, were sutured around 2 mm glass balls and implanted into the flanks of nude mice. Thirty-seven specimens were implanted and 31 harvested after 3, 6, 9 and 12 weeks. At 6 weeks the wall of the implanted cyst consisted of recognizable unkeratinized vaginal mucosa but had not healed completely at the sutured edges. From 9 weeks the cyst cavities were healed and the lumens lined by unkeratinized stratified squamous vaginal epithelium. The enclosing connective tissue had retained the characteristics of the lamina propria of the vaginal mucosa and could be distinguished from mouse tissue.

Central papillary atrophy of the tongue and denture stomatitis

A retrospective study of the epidemiologic data of 4,417 subjects has been undertaken to study the possibility of a link existing between glossal central papillary atrophy (median rhomboid glossitis) and denture stomatitis. Neither the association between glossal central papillary atrophy and denture stomatitis nor the association between glossal central papillary atrophy and denture use was statistically significant. However, the correlation between wearing removable dental prostheses and finding candidal mycelia in smears from these tongue lesions was statistically highly significant. Debilitation caused by general age changes would not appear to predispose to atrophy of the pappillae of the middle portion of the tongue-dorsum.

Evaluation of inbred germ-free Fischer 344 albino rats as an experimental model for oral candidiasis

Inbred germ-free Fischer 344 albino rats were evaluated as models for experimental candidiasis in order to investigate bacterial interaction with Candida albicans. Female rats were exposed to C. albicans in their drinking water and killed at intervals from 2 to 22 days after initial contact with the contaminant. C. albicans was cultured from their mouths from day 2 but from day 12 the number of colonies decreased. From day 2 to 9 all rats showed oral histological signs of candidal infestation, but after 9 days the number declined to 3 out of 9 at 22 days. The dorsal surface of the tongue was the best histological indicator of candidal infestation. All the rats had tongue lesions from day 4 to 9, and from day 6 there was also a concomitant localized loss of filiform papillae. The number of rats with all forms of tongue involvement also decreased after 9 days with only 3 out of 9 affected at 22 days. It is concluded that Fischer 344 inbred germ-free rats can be used on a limited scale as a model for candidiasis and bacterial interaction with C. albicans, the dorsal surface of the tongue would be the best site for studying candidal experimental lesions and it is probable that better results can be achieved with complete standardization of contamination and preparation procedures.