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Biomedical subjects

D G MacDonald

Publications and source records attributed to D G MacDonald.

At least 91 records · Page 5Linked to original sources
PubMed1982

Crohn's disease of the mouth: an indicator of intestinal involvement.

Nineteen patients with clinical evidence of oral Crohn's disease but no intestinal symptoms were studied. Oral lesions in all patients were shown histologically to have lymphoedema with or without chronic granulomas consistent with Crohn's disease. Seven patients (37%) had demonstrable intestinal disease on rectal biopsy and four of these had abnormal bowel radiology. All seven had evidence of nutritional deficiency. Patients with clinical features suggesting oral Crohn's disease may have evidence of Crohn's disease in the intestine, although this may not be clinically apparent.

Adolescent↗
PubMed1981

Hamster tongue carcinogenesis. I. Characteristics of the experimental model.

Thrice weekly applications of DMBA to hamster ventral lingual mucosa, preceded by scratching with a barbed broach, led to tumor development in over 75% of the animals by 28 weeks. Macroscopic ulceration did not appear to be a necessary precursor of epithelial malignancy in this model. Tumors were preceded by a phase resembling human leukoplakia. In addition to developing tumors in the treated area, 60% of the hamsters developed tumors in the floor of the mouth or the area of mucosa on either side of the median lingual frenum.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1981

Hamster tongue carcinogenesis II. Quantitative morphologic aspects of preneoplastic epithelium.

Stereological techniques have been used to quantify some morphologic aspects of non-neoplastic and preneoplastic hyperplasia in hamster tongue. Scratching hamster ventral lingual mucosa and applying acetone thrice weekly resulted in moderate epithelial hyperplasia in biopsy material removed at 16 weeks. There was a significant increase in the number of progenitor cells per defined histologic field and a striking increase in the number of progenitor cells related to each unit of surface length. There was a small but significant increase in basement membrane length. In the experimental group in which the ventral lingual mucosa was scratched and painted with 0.5% DMBA in acetone there was pronounced epithelial hyperplasia with increases in the thickness of the progenitor, maturation and keratinized compartments. Progenitor cells showed hyperplasia and hypertrophy. The number of progenitor cells related to each unit of surface length was significantly greater than normal or control values. There was a significant increase in the basement membrane length per field, reflecting an increased folding and prominence of the rete ridges.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1978

Aneurysmal bone cyst of the zygomatic arch.

A case is described of an aneurysmal bone cyst which, because of its normal anatomical location, caused considerable difficulties in diagnosis and clinical management. The literature concerning aneurysmal bone cysts of the jaw is reviewed and the pathogenesis of this rare but interesting lesion is briefly discussed.

Adolescent↗
PubMed1978

Persistent sialadenitis in an accessory parotid gland.

The patient who was followed had a persistent painful condition of the side of her face. Following a total parotidectomy, the symptoms presevered and this was ultimately diagnosed as being due to sialadenitis in the accessory parotide gland as well.

Adult↗
PubMed1978

Quantitative histological changes during early experimental carcinogenesis in the hamster cheek pouch.

Sequential changes in the hamster cheek pouch epithelium following application of the carcinogen dimethyl benzanthracene have been assessed using stereological techniques. The most important progressive change found following cessation of carginogen painting appears to be an increase in the number and size of progenitor cells. Much of the marked increase in stratum corneum thickness seen in the early stages appeared to be related to a hyperplasiogenic rather than a neoplasiogenic action of the carcinogen.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1977

Effects of the water-soluble carcinogen 4-nitroquinoline N-oxide on hamster lingual mucosa.

The water-soluble carcinogen 4-nitroquinoline N-oxide (4NQO) was painted onto hamster ventral lingual mucosa twice weekly for up to 20 weeks. No neoplasms developed during this period. The promoting agent croton oil was applied to the treated areas in an attempt to determine whether initiation had occurred. During the following 6 months, one animal developed a papilloma and three animals showed areas of epithelial atypia in the treated mucosa. No malignant neoplasms were seen. Despite its efficiency in producing intraoral neoplasms in the rat, 4NQO would appear to be a poor choice in the hamster.

4-Nitroquinoline-1-oxide↗