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Biomedical subjects

D G MacDonald

Publications and source records attributed to D G MacDonald.

At least 73 records · Page 4Linked to original sources
PubMed1986

The effect of iron deficiency on early oral carcinogenesis in the rat.

In order to further investigate the known influence of iron deficiency on 4NQO oral carcinogenesis in the rat, groups of iron-deficient and iron-sufficient Charles River white rats were painted with carcinogen for 8 weeks or 14 weeks and then left untreated for 32 weeks or 26 weeks respectively. Tumour development and epithelial dysplasia were assessed at the time of killing. Animals painted for 14 weeks showed more severe dysplasia than those painted for 8 weeks, but no significant differences were noted between corresponding iron-deficient and iron-sufficient groups.

4-Nitroquinoline-1-oxide↗
PubMed1985

Unusual myxomatous odontogenic tumour with calcification.

A jaw tumour in a child presented diagnostic difficulties because of the presence of myxomatous elements and actively forming cementum-like calcified material. The 5-year follow-up suggests that this was an unusual benign odontogenic tumour.

Calcinosis↗
PubMed1985

Oro-facial granulomatosis--a clinical and pathological analysis.

A study of 60 patients with oro-facial granulomatosis has been conducted and the clinical presentation of this disorder defined. It encompasses the previously recognised clinical entities of Melkersson-Rosenthal syndrome and cheilitis granulomatosa. The pathological features of the disease are lymphoedema and the presence of multiple non-caseating giant cell granulomata. These granulomata are histologically indistinguishable from those found in both gastrointestinal Crohn's disease and systemic sarcoidosis. Within this series of patients, nine had evidence suggestive of gastrointestinal Crohn's disease, and in six this was confirmed. A diagnosis of sarcoidosis was made in a further two patients. The relationship of oro-facial granulomatosis to these systemic granulomatous diseases is not yet clear. Patients with oro-facial granulomatosis who have gastrointestinal symptoms should be investigated for the presence of gastrointestinal Crohn's disease. Those without symptoms should be investigated for evidence of malabsorption or serological evidence of Crohn's disease. Within the present study, the erythrocyte sedimentation rate, full blood count, corrected whole blood folate, serum albumin and calcium were the most sensitive markers of gastrointestinal involvement. Sarcoidosis should be considered in all patients with oro-facial granulomatosis. The absence of clinical signs suggestive of sarcoidosis, a normal chest radiograph and normal levels of serum angiotensin-converting enzyme makes sarcoidosis unlikely.

Adolescent↗
PubMed1984

Cell kinetics of hamster ventral tongue epithelium in iron deficiency.

The cell-kinetic parameters of labelling index and duration of the S phase of the cell cycle (Ts) were investigated in the ventral tongue epithelium of hamsters with experimentally-induced iron deficiency. The labelling indices in animals with iron-deficiency anaemia and iron deficiency without anaemia did not differ from normal, but the Ts values were significantly shorter indicating an increased cell-production rate. The epithelial cell-kinetic parameters of iron-depleted animals did not differ from normal, but the labelling index was greater than in animals with the more severe stages of iron deficiency.

Anemia, Hypochromic↗
PubMed1984

Effect of prolonged iron deficiency on enamel pigmentation and tooth structure in rat incisors.

The effect of iron deficiency maintained for over 6 months on the pigmentation and structure of incisors was investigated in female white rats. Gross loss of pigmentation was observed. Sections revealed enamel hypoplasia and aplasia. Dentinogenesis was much less affected, but there were areas of altered dentine with abnormal tubules and increased thickness of predentine with cellular and vascular inclusions.

Anemia, Hypochromic↗
PubMed1984

Allergy to dental gold.

Allergy to gold dental appliances in very rare. This article reports the case of a patient who presented with acute oral ulceration following the placement of a gold crown. Biopsy of the ulcer and adjacent mucosa showed histologic features typical of a contact sensitivity. The patient subsequently had a positive patch test reaction to gold chloride. The literature is reviewed, and the dental implications are discussed.

Crowns↗
PubMed1983

The effect of iron deficiency on experimental oral carcinogenesis in the rat.

The effect of iron deficiency on oral carcinogenesis was investigated in 30 young adult male Charles River white rats. In 15 animals, prior to the start of carcinogen treatment, iron deficiency anaemia was produced and subsequently maintained by a combination of low iron diet (12 mg Fe2+ kg-1 diet) and repeated venesection. Fifteen control animals were fed the same diet supplemented with iron to approximately 140 mg FE2+ kg-1 diet. All animals were treated with the carcinogen 0.5% 4-Nitroquinoline-N-oxide in propylene glycol which was painted on the palate 3 times weekly. Animals were killed when tumours were grossly evident. The mean haemoglobin levels at the start of carcinogen applications were 10.1 g dl-1 in the anaemic group and 14.1 g dl-1 in the control group, and at the time of killing were 8.2 g dl-1 in anaemic animals and 13.8 g dl-1 in controls. The incidence of animals developing squamous cell carcinomas was similar in both groups, but tumour development was significantly earlier in iron-deficient animals (mean 183 days) compared to controls (mean 229 days). Iron-deficient animals showed a significantly greater incidence of tongue tumours and control animals showed a significantly greater incidence of palatal tumours.

4-Nitroquinoline-1-oxide↗
PubMed1983

The role of iron deficiency in experimentally-induced oral candidosis in the rat.

In comparison with normal rats, those with iron deficiency anaemia showed no significant difference in susceptibility to experimental infection with Candida albicans although anaemic rats had a significantly greater incidence of persistent infection. These findings support the suggestion that patients with chronic candidosis should be investigated for iron deficiency.

Anemia, Hypochromic↗
PubMed1982

Quantitative histological analysis of the epithelium of the ventral surface of hamster tongue in experimental iron deficiency.

Quantitative analysis of the ventral tongue epithelium of iron-deficient hamsters revealed significant progressive alterations in epithelial compartment thickness. As iron deficiency developed there was an initial increase in the proportion of the epithelium made up by progenitor cells and a decrease in the proportion formed by maturing cells. With increasing degree of deficiency, the maturation compartment formed less, and the keratinized compartment more, of the epithelium until, at the stage of anaemia, there was a significant reduction in the maturation compartment and a significant increase in the keratin thickness.

Anemia, Hypochromic↗
PubMed1982

Oral mucosa and complete dentures.

The reduction in the epithelial thickness under dentures did not reach the level of significance. The significant reduction in the epithelial morphology indicating a flatter basement membrane would suggest that the epithelium undergoes an adaptive change as a result of surface loading to produce a more uniform epithelium. The degree of keratinization was less and the stratum corneum was thinner in the epithelium under dentures. The complete dentures in these studies seemed to reduce the quantity and quality of the keratin layer. This study has shown that the presence of a denture produced a more regular epithelium with few rete ridges, and a thinner, less highly keratinized stratum corneum.

Adolescent↗