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Biomedical subjects

M D Walsh

Publications and source records attributed to M D Walsh.

11 recordsLinked to original sources

An immunohistological demonstration of c-erbB-2 oncoprotein expression in primary urothelial bladder cancer.

Sections of formalin-fixed, paraffin-blocked tissue from 116 primary transitional cell carcinomas were stained immunohistochemically using a polyclonal antibody against the c-erbB-2 oncoprotein. Positive staining of cell membranes, known to correlate with gene amplification, was seen in 22 (19%) of the 116, with variable staining from tumour to tumour and within tumours themselves. Consistent with its mooted value as a prognosticator in bladder cancer, the c-erbB-2 oncoprotein was detected in 13 (of 40) grade III and 9 of the 26 muscle-invasive tumours examined compared to 1 (of 25) grade I and 6 (of 66) mucosa only (pTa) lesions. These results support further examination of c-erbB-2 expression in bladder cancer.

Aged

Intestinal transferrin receptors and iron absorption in the neonatal rat.

The transferrin receptor is a major protein found on the basolateral membranes of intestinal epithelial cells, yet its possible role in intestinal iron metabolism and also in iron absorption is unclear. We have studied intestinal transferrin receptor expression during the peri- and postnatal development of the small intestine of the rat using immunohistochemistry with a monoclonal antibody to the rat receptor. Two major changes in transferrin receptor expression in the developing small intestine were found, a decrease in receptor expression associated with birth, and an increase at the time of weaning. Around the time of weaning there was a large decrease in iron absorption, but there was no direct correlation between absorption and transferrin receptor expression. However, at both birth and weaning there were major changes in intestinal cell kinetics, and the distribution of receptor correlated well with the distribution of proliferating cell populations. In addition, as the intestinal epithelial cells differentiated and stopped dividing, there was a redistribution of transferrin receptors from the cell surface to intracellular sites. These data suggest that the most likely role of the transferrin receptor in the neonatal intestine is in the supply of iron to the developing epithelial cells in the crypts, and that the receptor does not play a direct role in iron transit across the intestinal epithelium.

Aging

A comparison of epidermal growth factor receptor (EGFR) and c-erbB-2 oncogene expression in head and neck squamous cell carcinomas.

The proto-oncogenes c-erbB-2 and epidermal growth factor (EGF) receptor which encode 2 closely homologous transmembrane glycoproteins have been found amplified and/or overexpressed in a range of epithelial malignancies. In a series of 46 head and neck squamous cell cancers (SCCs), immunohistochemical reactivity for the EGF receptor was detected in all cases, particularly at the invading edge of cellular islands of SCC and in the basal cells of normal adjacent squamous epithelium. Southern blot analysis demonstrated EGF receptor gene amplification in 3 cases. In contrast, strong membrane staining for the c-erbB-2 oncoprotein was not detected in any sample, and there were no cases of c-erbB-2 gene amplification. Despite a close structural and (presumed) functional homology between these 2 receptor-oncoproteins in the development of malignancy, we report that their expression in SCCs is markedly different. Furthermore, unlike the situation for breast cancer, quantitation of the c-erbB-2 or EGF receptor oncoproteins is unlikely to yield important prognostic information in this group of patients.

Adult

Transferrin receptor expression in primary superficial human bladder tumours identifies patients who develop recurrences.

A group of 65 patients with superficial bladder carcinoma was followed for 2 years and tumour recurrence rate was correlated both with transferrin receptor status of the initial primary tumour and with the results of voided urine cytology. Nine of 24 patients with transferrin receptor negative tumours had recurrences compared with 30 of 41 patients with transferrin receptor positive tumours. This difference was highly significant. Urine cytology at presentation was also predictive of further tumour formation: of 30 patients who were transferrin receptor positive and had positive urine cytology, 25 developed recurrences.

Adult

An immunohistological examination of inflammatory cell infiltration in primary testicular seminomas.

Inflammatory cell infiltration was characterized in five classical seminomatous testicular tumours using immunohistochemical techniques. These cells of immunological lineage were sited mostly around vessels. Lymphocytes were the most numerous, T cells outnumbering B cells in all sections studied. The helper/inducer subgroup predominated in the T cell family with suppressor cells more common than cytotoxic cells. Plasma cells constituted only a small percentage of this population as did natural killer cells. No Langerhans cells were identified. Phagocytic macrophages were twice as common as antigen-presenting macrophages yet T lymphocytes were 15 times more common than these antigen-presenting macrophages.

Antibodies, Monoclonal

An immunohistopathological characterisation of mixed non-seminomatous germ cell tumors.

Immunohistological techniques were used to characterise inflammatory cell infiltrates in mixed germ cell tumours. The distribution of these infiltrates was much more variable than in pure seminomas but could not be related accurately to any particular tumour type. There were approximately equal numbers of B and T cells in these areas and helper/inducer T cells were more common than suppressor/cytotoxic lymphocytes. Within these areas of inflammatory cells, the subtype composition was similar to that seen in pure seminomas.

B-Lymphocytes

Transferrin receptor expression by human bladder transitional cell carcinomas.

The expression of transferrin receptors (TFR) by normal and neoplastic urothelial cells was studied in "control" patients and in patients with transitional cell carcinoma of the bladder. These tumours were graded independently and consisted of 19 grade I, 30 grade II and 19 grade III lesions. TFRs were identified using a monoclonal antibody specific for TFR (OKT9) in an immunofluorescent or avidin/biotin-immunoperoxidase technique on fresh frozen sections. TFRs were not detected on normal urothelium. However, positive staining was found to increase with increasing pathological grade and stage of the tumours, ranging from 31.6% of grade I to 78.9% of grade III tumours and 51.2% of pTa (mucosa only lesions) to 87.5% of pT2/pT2+ (muscle invasion +/- deeper) primary urothelial malignancies.

Adult