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Biomedical subjects

D G MacDonald

Publications and source records attributed to D G MacDonald.

At least 19 recordsLinked to original sources
PubMed1992

Rat palatal histology related to denture-like appliances.

Two designs of palatal denture-like appliance were fitted to rats. Tooth- and tissue-borne appliances caused changes in epithelial thickness and keratin thickness, but these varied with anatomical site and type of appliance. A single inoculation of Candida albicans at the time of insertion of the appliance failed to establish infection consistently. Debris accumulation under the appliances was a problem which will restrict long-term studies with this model.

Animals↗
PubMed1991

Light microscopic, cytochemical and ultrastructural studies of a rat odontogenic epithelial cell line.

An odontogenic epithelial cell line, ROE-2B, was established by propagating disaggregated immature, unmineralized maxillary third molar tooth germs from 11-day old Sprague-Dawley rats on a feeder layer of Mitomycin-C treated NIH 3T3 embryonic mouse fibroblasts. The cell line has been maintained for more than 6 months and through 7 passages. Light microscopic examination of cells revealed colonies with epithelial morphology. Electron microscopic examination confirmed the epithelial nature by the demonstration of tonofilaments, desmosomes and basal lamina. Cells were also shown to have secretory vacuoles, an abundance of granular endoplasmic reticulum, free ribosomes, Golgi complex and mitochondria. Surface activity in the form of pseudopodia-like projections and micropinocytosis were noted. Epithelial cells forming keratin were demonstrated by a positive histochemical reaction with Rhodanile Blue. Immunohistochemical studies showed a positive reaction for CAM 5.2 indicating that the ROE-2B cells express the cytokeratins of simple or glandular epithelia. The ROE-2B cell line will be useful for studies on in vitro biological behaviour of odontogenic epithelial cells, and may allow the establishment of in vitro models of odontogenic tumours.

Animals↗
PubMed1990

Histological, microbiological and haematological investigations in denture-induced stomatitis.

Biopsy specimens of palatal mucosa from 10 edentulous female subjects exhibiting the signs of chronic atrophic denture-induced stomatitis were fixed and processed to produce sections which were quantitatively analysed by light microscopy. The type and degree of surface keratinization, the epithelial thickness and basement membrane morphology were assessed. Microbiological and haematological evaluations were related to the histological findings. It was found that within this clinical entity of palatal inflammation there was considerable variation in tissue response at a cellular level, and that the numbers of organisms associated with the inflammatory reaction appeared to be fewer in patients with abnormal haematological status.

Adult↗
PubMed1990

Adenomatoid odontogenic tumour. A survey of 21 cases from Sri Lanka.

A series of 21 cases of adenomatoid odontogenic tumour is reported from Sri Lanka. They formed 8.6% of odontogenic tumours, excluding odontomes, in the 10-year period reviewed. 85% of cases occurred in the anterior maxilla. Most cases were diagnosed clinically as dentigerous cysts. There were no recurrences following conservative surgery in follow-up periods ranging from 2 to 11 years.

Adolescent↗
PubMed1989

Treatment of candidal leukoplakia with fluconazole.

A case of candidal leukoplakia (chronic hyperplastic candidosis) treated with the systemic antifungal agent, fluconazole, is reported. Dramatic clinical and histopathological resolution of the condition occurred following 11 days of drug therapy.

Antifungal Agents↗
PubMed1989

Age changes in the human inferior alveolar artery--a histological study.

The inferior alveolar artery was examined histologically in non-irradiated surgically resected mandibles. A total of 39 edentulous and 11 partially dentate specimens was studied. Narrowing of the lumen was most commonly due to arteriosclerosis which confirms previous reports. Stenosis was not found to be either commoner or more severe than that recorded in other arteries in the body. It is suggested that apparent narrowing of the inferior alveolar artery seen on angiography may represent a form of involutional atrophy of the artery associated with dental extraction and progressive resorption of the residual occlusal alveolar ridge.

Adult↗
PubMed1989

Sampling of jugulo-digastric lymph nodes in oral cancer.

A modified method of histologic sampling involving multiple blocks has been applied to 37 jugulo-digastric nodes dissected from freshly submitted neck dissection specimens from patients with oral squamous cell carcinoma (SCC). Seventeen of these nodes had been found to be free from tumor following standard sampling. The method was also applied to a further 29 jugulo-digastric nodes that had been previously reported as being free from metastatic tumor. Only one of the 46 nodes previously reported as negative was found to contain secondary tumor following more extensive sampling.

Carcinoma, Squamous Cell↗
PubMed1989

Histological identification of mitosis in oral mucosal lesions--problems and solutions.

Additional criteria for identification of mitosis in conventional histological sections of the oral mucosa were devised. The application of these criteria and the use of Harris's haematoxylin have helped to resolve some inconsistencies in recognizing mitotic figures which are slightly different from those seen in classical cell culture studies.

Carcinoma, Squamous Cell↗
PubMed1988

Assessment of the pathogenicity of bacterial species isolated from acute dentoalveolar abscesses.

The pathogenicity of 20 strains belonging to nine bacterial species isolated from acute dentoalveolar abscesses was assessed individually and in two species combinations by subcutaneous inoculation of mice. Infections were produced by all the bacteria although variations were seen both in the type of lesion produced and the subsequent recovery of viable bacteria. Anaerobic gram-negative bacilli were recovered more often (p less than 0.05) at high concentrations (10(6)-10(9) cfu/ml) and produced a localised abscess with peripheral necrosis more frequently (p less than 0.001) than either Streptococcus milleri or anaerobic gram-positive cocci. Lesions induced by a combination of bacteria comprising anaerobic gram-negative bacillus and any other species yielded both strains at high concentration more often (p less than 0.001) than a combination comprising anaerobic gram-positive cocci and S. milleri. It is concluded that anaerobic gram-negative bacilli are major pathogens in acute dentoalveolar abscesses.

Acute Disease↗
PubMed1988

Mitotic phase distribution in oral epithelial hyperplasia and neoplasia.

Assessment of mitotic phase distribution in oral epithelial lesions has shown closely similar features in two categories of hyperplastic condition. By contrast, squamous cell carcinomas showed a significantly different mitotic phase distribution with an increased proportion of metaphases suggesting delay or blockage at this phase. Squamous cell papillomas showed an increased proportion of prometaphase mitoses.

Carcinoma, Squamous Cell↗
PubMed1987

Effect of 2 episodes of cryosurgery on carcinogen-treated hamster cheek pouch.

Hamster cheek pouches were treated with the topical carcinogen DMBA for 8 weeks. 2 episodes of cryosurgery, located within the area of previous carcinogen application enhanced the neoplastic process by comparison with matched controls. Comparison with previous studies suggests that the 2 episodes of cryosurgery may have a greater effect in provoking overt malignancy than a single episode of cryosurgery.

9,10-Dimethyl-1,2-benzanthracene↗