Thesis (M.D.S.)--University of Hong Kong, 2004. / Also available in print.

Master of Science / Biochemistry / Gerald Reeck / Laccases belong to the “multicopper oxidase” family of proteins, and can oxidize o-diphenols and p-diphenols in the presence of molecular oxygen. Laccases have been well characterized in wood-rotting fungi where they appear to play a role in lignin degradation, morphogenesis, and stress defense. More recently, laccase-2 has been found to play a role in the insect cuticle sclerotization and tanning. In addition, it has been hypothesized that laccase-1 may be involved in the oxidation of toxic phenolic compounds ingested by insects during feeding. A laccase-type phenoloxidase has been identified in the pea aphid, Acyrthosiphon pisum (Harris) using a combination of substrates that react with laccase. Within the pea aphid, laccase-1 transcript was found to be localized within the gut and the salivary glands. Finally, the specific regions where laccase-1 was present in the salivary gland was visualized using immunohistochemistry.

Cystadenocarcinoma of the salivary glands is a very rare, slow growing, low-grade malignant neoplasm. However, when it occurs, it poses a diagnostic challenge. They are usually well circumscribed and exhibit multicystic appearance. The cytological features of fine-needle aspirates show bland appearing papillary and micropapillary neoplasm with variable cellularity and absence of cytological atypia. The cells are small to medium in size with abundant and occasionally vacuolated cytoplasm. The nuclei are eccentric, bland appearing, round, and at the most part uniform in size without anaplasia or mitotic activity. The background is commonly mucoid. Histologically, the neoplasm is usually well circumscribed and contains variably sized multicys-tic spaces with papillary structures. Foci of definite stromal invasion by tumor cells have to be present to justify the diagnosis of carcinoma. The remainders of the cytological features are similar to these seen on cytological smears. Typically, they are slow growing and conservative, but complete surgical excision is considered adequate. We present a case in a 57-year-old Saudi man that we believe the first from our region demonstrating the clinical and pathological features.

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Thesis (doctoral)--Karolinska Institutet, Stockholm, 1989. / Extra t.p. with thesis statement inserted. Includes bibliographical references.

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