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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
PubMed1995

Use of mesenteric lymphangiography in a calf with chylothorax and chyloperitoneum.

Lymphatic abnormalities resulting in chylous effusion into a body cavity are uncommon in domestic animals. In a 6-day-old calf admitted to our hospital because of failure to suckle and abdominal distention, however, mesenteric lymphangiography revealed an obstruction of lymphatic flow. Laparoscopic examination of the abdomen was unsuccessful. Fluid accumulation was resolved in this calf by drainage. In cattle with chylothorax and concurrent chyloperitoneum in which a traumatic lesion of the thoracic duct is possible, conservative management, with drainage and supportive treatment, should be attempted prior to considering surgical intervention.

Animals↗
PubMed1995

The influence of rate of cell entry to S phase on the labelling index of human buccal epithelium.

The physiological basis of the circadian rhythm in cell kinetics in human epithelia remains unclear. A 24-h periodicity in the labelling index (LI) of human buccal epithelium has been demonstrated previously. A double-labelling technique in vitro using tritiated deoxythymidine was used here to examine fluctuations in the time spent in S phase (Ts) and the rate of cell entry to S phase (S influx). While the range in Ts values was limited (5.1-6.9 h), influx to S phase ranged from 0 to 1.26% per hour at six different time periods. An increase in the S influx was apparent around 18:00 h leading to a peak LI 4 h later. These preliminary data indicate that the most likely kinetic mechanism related to circadian variations in LI is a variable G1-S influx at this site.

Adult↗
PubMed1995

Post-irradiation changes in the blood vessels of the adult human mandible.

Changes in the inferior alveolar artery and periosteal vessels of the post-irradiation mandible have been investigated. The inferior alveolar artery underwent comparatively little change, stenosis being noted in just over half the specimens examined. The number of periosteal arteries and veins increased, the changes being most marked on the body where the effective tissue dose of radiation was highest. The increase in periosteal vessels was independent of stenosis of the inferior alveolar artery.

Aged↗
PubMed1995

Basal cell cytoplasmic autoantibodies in oral lichenoid reactions.

One hundred sixty-one patients with a clinical diagnosis of an oral lichenoid reaction were evaluated serologically for circulating autoantibodies toward basal cell membrane components. The study group comprised 119 women and 42 men with a median age of 59 and 55 years, respectively. Most patients (n = 144) had an oral mucosal biopsy undertaken. Serologic investigation aimed to identify an IgG antibody that, under immunofluorescent staining, produced an annular fluorescence of basal cells and that has been referred to as basal cell cytoplasmic antibody. These basal cell cytoplasmic antibodies were significantly associated with systemic drug usage, histologic diagnosis of a lichenoid reaction, and a unilateral intraoral distribution of the clinical lesion. In the diagnosis of oral lichenoid reactions precipitated by drug therapy, the basal cell cytoplasmic phenomenon may be a useful adjunct to clinical and histologic investigation.

Adolescent↗
PubMed1995

Epithelial cell kinetics in oral leukoplakia.

Cell proliferation in oral leukoplakia has been studied by estimating the number of cells in the S phase using in vitro 3H thymidine labelling. The labelling index was found to be increased 1.77 fold in leukoplakias compared to the clinically normal control sites (P < 0.005). This rise in labelling index was found to be related to an increase in the proportion of the cells in the basal cell layer engaged in cell production. Both leukoplakia and the control specimens showed epithelial atypia, although in the latter samples this was mild yet suggestive of a possible field change in the oral epithelium of a small group of tobacco users. A significant positive correlation was found between the epithelial atypia score and the labelling index. This raises the possibility of using the labelling index as an objective prognostic marker in assessing potential malignancy in oral leukoplakia lesions.

Analysis of Variance↗
PubMed1994

Flow cytometric analysis of DNA content in squamous carcinoma of the tongue: the relationship to host and tumour factors and survival.

Cellular DNA content has been found to be an important prognostic factor in many human tumours, yet within the head and neck region few studies have examined its effect on survival and in those that have, findings differ. Eighty-one consecutive patients with squamous carcinoma of the tongue mainly treated by surgery and post-operative radiotherapy were studied. The DNA content of archival paraffin embedded tumours was measured by flow cytometry. Fifty-seven tumours were diploid and 24 were aneuploid. There was no association between ploidy status and age, sex, tumour size or nodal status. Ploidy status was not related to survival. These findings indicate that analysis of tumour DNA content in squamous carcinoma of the tongue does not provide any additional prognostic information for the individual patient.

Aneuploidy↗
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↗