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Biomedical subjects

D Birt

Publications and source records attributed to D Birt.

30 records · Page 2Linked to original sources

Profile of malignant disease in the mouth clinic.

Between 1973 and 1981, 2,056 new patients were seen in the Mouth Clinic at Sunnybrook Hospital. Of these 109 proved to have malignant disease, with squamous cell carcinoma being the commonest type. Lower lip and floor of mouth were the most frequent sites. There was a high proportion of small tumors and local surgical excision was the most widely employed primary method of treatment. Radiation and combined treatment were used in larger lesions. Twenty-four patients have so far died of mouth cancer and the presence of enlarged lymph nodes at presentation was an ominous sign. Although containing the usual high proportion of heavy smokers and drinkers this group of patients at present exhibits a lower incidence of second primary malignancies than in some published series. It is concluded that surgery and radiotherapy have equivalent effectiveness in treating small primary lesions, where a policy of observation of the clinically negative neck appeared justified. The best treatment for large lesions and the most appropriate management of the clinically negative neck in intermediate size lesions has not been determined.

Adult↗

Current knowledge of pancreatic carcinogenesis in the hamster and its relevance to the human disease.

Syrian hamsters present a unique species for induction of pancreatic tumors that in many aspects resemble human pancreatic cancer. The specific response of Syrian hamsters, in contrast to may other rodents, for development of pancreatic ductal (ductular) tumors is not yet known. All pancreatic carcinogens thus far tested show certain common features. They are all nitrosamines that possess or can be metabolized to compounds with 2-oxopropyl- or 2-hydroxypropyl substituents. All but one, N-nitroso-methyl(2-oxopropyl)amine, occur or metabolize to nitrosamines with the ability to cyclize and form structures resembling glucose. Hence it is suggested that this cyclic structure may be responsible for the pancreatic carcinogenicity of these nitrosamines, as has been proposed for the pancreatotropic effect of streptozotocin. It is also of further interest that one pancreatic ductal (ductular) carcinogen, N-nitroso-2-methoxy-2,6-dimethylmorpholine, which possesses a totally cyclic structure, acts, like streptozotocin, as beta-cell cytotoxic and diabetogenic when given in a high single dose. Modification of pancreatic tumor induction has been demonstrated by specific procedures. A high fat diet significantly increases both the incidence and number of induced cancers. Methods for early diagnosis and therapy are being developed and their significance and applicabilities for clinical use will be of major importance. Compared with the other most common types of human cancer, pancreatic cancer has extraordinary characteristics, which make the disease one of the most mysterious of maladies. Consequently, pancreatic cancer represents a serious international problem and requires urgent resolution, especially with regard to its etiology, early diagnosis, prevention, and therapy.

Animals↗

Diagnosis and management of long-standing benign oral ulceration.

The authors formed a Mouth Clinic at Sunnybrook Hospital in 1973 since when there have been 3025 patient visits. Those patients with chronic ulceration present a challenge, the diagnosis sometimes being difficult and therapy not rapidly effective. The differential diagnosis includes lichen planus, pemphigus vulgaris, benign mucous membrane pemphigoid, discoid lupus erythematosus, erythema multiforme, aphthous ulcers, Behcets disease, periadenitis mucosa necrotica recurrens, specific infections and iatrogenic causes. It is possible to reach a definite diagnosis in virtually every case by means of a good history and careful clinical examination supplemented by biopsies and in some cases direct and indirect immunofluorescent studies. Treatment emphasizes scrupulous attention to oral hygiene with baking soda mouthwashes and careful teeth cleaning to minimize the accumulation of dental plaque. Specific therapy includes topical steroids in lichen planus, intra muscular gold in benign mucous membrane pemphigoid, a previously unreported treatment which considerably improved seven out of ten patients, and tetracycline mouthwashes in aphthous ulcers.

Behcet Syndrome↗

Oral manifestations of herpes simplex virus infections.

Most individuals are infected with Herpes Simplex in childhood usually suffering a mild febrile illness of no consequence. Later some individuals suffer recurrent infections which appear as cold sores on the lip while others intermittently shed virus in the oro-pharygeal secretions. Adults uninfected in childhood may be exposed to viruses for example by kissing and develop an acute primary herpes with fever and gingivo-stomatitis occasionally requiring hospital admission. Awareness of this condition is required for diagnosis after which the majority of patients seen in otolaryngological practice need only supportive therapy, explanation and reassurance. Recurrent cold sores are no more that a nuisance in most patients, but occasionally they are severe and in others the cold sore may precipitate oral erythema multiforme. Unfortunately the treatments available for recurrent cold sores are rather unsatisfactory.

Erythema Multiforme↗

Correlation of tumor volume with local control in laryngeal carcinoma treated by radiotherapy.

An analysis of 37 patients with laryngeal carcinoma (T2 or greater) treated with radical radiotherapy, with surgery reserved for failure, was performed to determine if tumor volume, alone or in association with other prognostic factors, accurately predicted the probability of local control. Patient records were reviewed retrospectively and the following data extracted: age, sex, laryngeal region and number of sites involved by tumor, T and N categories, and success or failure of radiotherapy. Tumor volume for each patient was calculated from pretreatment computed tomograms by summing the products of the cross-sectional tumor area on each CT cut and the interval in millimeters between sequential CT cuts. The mean tumor volume for patients failing radiotherapy was 21.8 cm3, and the mean volume for patients primarily controlled by radiotherapy was 8.86 cm3. Tumor volume significantly predicted disease-free interval (p = .045) and outcome with radiotherapy (p = .02). The study suggests that tumor volume is a significant factor in determining the outcome of primary radiotherapy in advanced laryngeal carcinoma.

Adult↗