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Biomedical subjects

M A Mackenzie

Publications and source records attributed to M A Mackenzie.

5 recordsLinked to original sources
PubMed2004

Follicular non-Hodgkin's lymphoma with refractory paraneoplastic pemphigus: case report with review of novel treatment modalities.

In this paper a patient with a non-Hodgkin's lymphoma (NHL) and paraneoplastic pemphigus (PNP) is described. PNP is a very rare, painful mucocutaneous intraepithelial blistering disease associated with occult or confirmed malignancy. Patients with PNP show severe, progressive mucocutaneous disease with a high mortality rate, because of drug-induced infectious complications. The patients sometimes benefit from high doses of oral corticosteroids. However, pulse therapy with high doses of prednisolone (or dexamethasone) in combination with other immunosuppressants induces variable and inconstant results. Intravenous immunoglobulin (IVIg) has been applied in different cases of PNP with encouraging results. Plasmapheresis or plasma exchange (PE) in combination with corticosteroids and/or cyclophosphamide or azathioprine showed similar rapid and beneficial results in association with decreasing auto-antibody levels in this group of refractory pemphigus. Another interesting therapeutic option is rituximab, a chimeric monoclonal antibody directed against the CD20 antigen, which is found on the surface of normal and malignant B-lymphocytes. Administration of rituximab for patients with PNP in combination with follicular NHL is not always successful regarding oral lesions as we report in this case. PE leading to prompt depletion of autoreactive antibodies combined with immunosuppressants or synchronisation of PE with IVIg seems the best treatment modality for this refractory group, but the therapeutic value and appropriate timing of rituximab obviously deserve further evaluation in patients with low grade NHL and PNP.

Adrenal Cortex Hormones↗
PubMed1997

Activation of the receptor tyrosine kinase Kit is required for the proliferation of melanoblasts in the mouse embryo.

The development of neural crest-derived melanocytes, as well as haematopoietic and germ cells, is affected by mutations of the Kit and Mgf genes, which lead to dominant spotting (W) or steel (Sl) phenotypes. Mgf codes for the ligand of the receptor tyrosine kinase encoded by the Kit locus. KitW-v, a point mutation exerting a dominant negative effect, causes a substantial reduction in tyrosine kinase activity of the Kit receptor and leads to a characteristic pigmentation phenotype, namely dilute coat colour and a white ventral and head spot with reduced pigmentation of the feet and tail in the heterozygous animal, as well as slight anaemia. Homozygous animals lack coat pigmentation and are severely anaemic and infertile. Dct is a marker for cells of the melanoblast lineage. In order to study these cells in detail we have generated transgenic mouse lines carrying the lacZ reporter under the control of the Dct promoter and have used the embryonic expression of the reporter to identify early melanoblasts before they begin to produce pigment. Our transgenic lines have simplified the study of melanoblasts in the mouse embryo, and by crossing our mice with KitW-v mutants we have been able to identify the midgestation stages at which melanoblasts rely critically on Mgf/Kit interactions. We conclude that the survival of immature melanoblasts depends crucially upon Kit signalling up until E11, and later in development Kit plays a vital role in melanoblast proliferation. Our data do not describe a dependence upon Kit for melanoblast migration or differentiation.

Animals↗
PubMed1988

Adjuvant chemotherapy in premenopausal patients with primary breast cancer; relation to drug-induced amenorrhoea, age and the progesterone receptor status of the tumour.

Adjuvant chemotherapy with cyclophosphamide, 5-fluorouracil and methotrexate (CMF)-induced permanent ovarian suppression in 47 of 77 (61%) premenopausal patients with axillary node positive breast cancer. After a median observation time of 37 months the relapse-free and overall survival times were significantly longer for patients with permanent amenorrhoea. A strongly positive correlation between CMF-induced amenorrhoea and age of the patients, as well as between age and the tumour PgR status, was found. The induction of ovarian suppression predominantly occurs in patients with PgR positive tumours and may add an endocrine effect to the cytotoxic action of adjuvant chemotherapy in this particular group of older premenopausal women.

Adult↗