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Query: UMLS:C0025202 (melanoma)
 69,561 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Proteolytic activities were measured in extracts of human skin melanoma, lymphatic metastasis and in nonmalignant naevi by using various proteinase substrates as well as plasminogen activator assay. pH-optima for hydrolysis of various proteinase substrates by these tumors were found to be essentially the same as in healthy human skin. Melanoma extracts were found to especially readily hydrolyze N-alpha-benzoyl-DL-arginine beta-naphthylamine (BANA) at pH 5.8 in the presence of 1 mmol/l dithiothreitol and EDTA (cathepsin B1-like enzyme) as well as histones and p-tosyl-L-arginine methyl ester (TAME) at pH 7.5, and showed increased capacity to activate plasminogen when compared to nonmalignant naevus. The possible role of proteinases in malignant melanoma is discussed.
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PMID:Proteolytic enzymes and plasminogen activator in melanoma. 3 88

In vitro cell mediated cytotoxicity (CMC) assays have been conducted in a human melanoma system with a 3H-proline retention technique. Melanoma target cells from long-term cultures ("cell lines") are found to exhibit increased susceptibility for lymphocyte cytotoxicity in comparison to the same target cells from short-term culture. The higher sensitivity of the "cell line" derived target cells is seen with lymphocytes, irrespective of diagnosis of the donor. In parallel experiments with the target cells grown in medium supplemented with fetal calf serum (FCS) and AB+ human serum (from a normal male doner), the melanoma target cells grown with FCS do not show any enhanced cytotoxicity, suggesting no causal relationship of such enhanced sensitivity of "cell line"-derived target cells to "heterologous melanoma antigens" that might have been acquired by the target cells following the use of FCS in tissue culture. In controlled assays of in vitro CMC, lymphocytes from melanoma patients (14/44) exhibited selective cytotoxicity (destruction of only one target-cell type) against the melanoma target cells, whereas only 3/97 control lymphocytes (other malignancies and normal donors) showed such melanoma-selective cytotoxicity. This difference is statistically significant at p less than 0.001. Non-selective cytotoxicity (destruction of two or more unrelated target cell types) was seen with lymphocytes from 9/44 melanoma patients, 13/51 patients with other malignancies and 8/46 normal donors. No correlation of selective cytotoxicity could be established with donors' age, sex, stage of disease, therapy or history of blood transfusion. Such a correlation may emerge as our series becomes larger. Despite the lack of any correlation between selective cytotoxicity and disease status, our study reaffirms the existence of selective cytotoxicity by melanoma patients' lymphocytes against melanoma target cells.
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PMID:Selective and non-selective lymphocytotoxicity in human melanoma: observation on the effect of long-term culture and fetal bovine serum on target-cell sensitivity to lymphocytes. 5 12

Antibody-dependent cell-mediated cytotoxic assays have been used to examine antigens on human melanoma cells obtained either directly from patients or from long-term melanoma cell lines. A panel of melanoma antisera was selected from human subjects which could be shown not to have significant reactivity to histocompatibility antigens. With these antisera extensive cross-reactions between melanoma cells were found. However, the cross-reactivity was incomplete and the pattern of reactivity was different for each antiserum tested. These results were not consistent with a common melanoma antigen on human melanoma cells but rather indicated heterogeneity of melanoma antigens and multiple antibody specificities in the sera tested. This appeared to be confirmed by extensive cross-absorption studies which indicated limited cross-reactivity of antigens on melanoma cells from either long-term or short-term cultures. Several changes in the antigenic profile of melanoma cells in vitro from both long-term and short-term cultures were documented which resulted from contamination of the melanoma cell lines with non-melanoma cells and fibroblasts. Melanoma antisera may therefore be useful to mintor changes in long-term cultures which would otherwise give spurious results in in vitro tests. These results appear to have considerable significance for understanding tumour/host relationships and for the establishment of rational immunotherapeutic procedures and diagnostic tests in melanoma.
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PMID:Antigens on melanoma cells detected by leukocyte dependent antibody assays of human melanoma antisera. 6 19

Examination of the case-records of women presenting to the Melanoma Unit at Sydney Hospital over the period 1961-71 has shown that women with pregnancies before the development of melanoma had a better survival-rate from melanoma than women without previous pregnancies. The known presence of fetal antigens on melanoma cells and immunisation against fetal antigens during pregnancy suggest an immunological explanation for these results. Exposure to fetal antigens during pregnancy may protect against the dissemination of melanoma cells bearing similar fetal antigens and thus increase the survival-rate. The incidence of melanoma in males and females was approximately equal, which suggests that immune responses to tumour-associated antigens may be more effective in preventing spread of tumours than in preventing their occurrence.
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PMID:Previous pregnancy as a protective factor against death from melanoma. 6 63

Melanoma-associated antigens (MAA) were isolated and their functional immunologic properties were evaluated. Spent fetal calf serum-free culture media and 3-m KCI extracts of cultured human melanoma cells grown in this medium were used as antigen sources. Ultracentrifugal flotation on KBr was used to separate MAA and HLA antigens present in the extracts or spent culture media; thus interference by histocompatibility antigens was prevented in subsequent tests of tumor antigenic activity. MAA purified in this manner retained their immunologic functions as evidenced by their ability to produce delayed cutaneous hypersensitivity reactions in patients with melanoma, specifically combine with antimelanoma xenoantibody, and elicit production of functionally specific xenoantibody. Possible structural differences between HLA antigens and MAA were considered in evaluation of the data.
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PMID:Purification and immunologic evaluation of human melnoma-associated antigens. 7 78

Pathological features of twenty-one cases of malignant melanoma studied in the University of Nigeria Teaching Hospital, Enugu during the period January, 1974 to December, 1975 are presented. Malignant melanoma accounted for 2.4% of all tumours and 4.5% of all malignant tumours, greatest age incidence being in the fifth to seventh decades. The male to female sex ratio was 2:1. 73.2% of cases were of the nodular variety. 81% melanomas occurred on the sole of feet validating the hypothesis that the pigmented skin in Africans is resistant to malignant melanoma. Melanoma in Nigerians would appear essentially to be arising from epidermal melanocytes and not from preexisting naevus cells. Hence we do not feel prophylactic removal of plantar moles as suggested by Onuigbo (1975) is desirable. Histologically, there was no clear association between the cell types and the kind of melanoma or invasion of the tumour. The difference in behaviour and natural history of malignant melanoma would appear to have a bearing on the local tissue and also general immune mechanisms of the host.
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PMID:Malignant melanoma in Nigeria-pathological studies. 9 49

Melanoma cells treated with dibutyryl cyclic AMP (db cAMP) for 24 h resulted in dendritic cells possessing parallel assembled microtubules. A23187 treatments resulted in a biphasic response: Long term effects of the ionophore were characterized by small epitheloid cells while the immediate response produced elongated cells with parallel arranged 10 nm microgilaments, characteristic of dispersive melanocytes.
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PMID:Ionophore A23187 and dibutyryl cyclic AMP effects on cell shape and morphology of B-16 melanoma. 18 29

Melanoma cell oncolysate, prepared with Newcastle disease virus, was administered as an immunostimulant to 13 patients with metastatic melanoma. The oncolysate was well tolerated. Six treated patients evidenced a decrease in the size of skin nodules or diseased lymph nodes. Visceral lesions were not favorably influenced to any marked degree. One case of fulminating disease showed a change to slow progression and survived a year longer than was otherwise expected. Another patient, whose melanoma could not be controlled by surgery or chemotherapy, has been in complete remission for 2 years. It appears that viral oncolysate might be particularly helpful to patients with early disease.
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PMID:Viral oncolysate in the management of malignant melanoma. II. Clinical studies. 19 40

It was shown on albino mice that when DOPA-3H (20 muCi/mouse) was administered before nonradioactive DOPA (1 mg/mouse) tritium accumulation in the tissue of Harding-Passi's melanoma of these mice proved to increase. Melanoma radioactivity in this experimental group was double that in the tumour tissue of the animals to which DOPA-3H alone was administered. Examination of the adenylate cyclase, phosphodiesterase activity and of the level of cAMP in melanoma of mice 2 hours after DOPA administration (1 mg/mouse) showed accumulation of cAMP and an increase in the phosphodiesterase activity; as to adenylate cyclase activity--it fell. It is suggested that DOPA realizes its effect not only as melanin precursor, but also through the cAMP system, influencing the melanogenesis enzymes activity.
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PMID:[Regulatory role of DOPA and components of the cyclic adenosine-3',5'-monophosphate system]. 20 73

The neurological manifestations of melanoma are analysed in this review of 1,500 patients in the Queensland Melanoma Project from 1963 to 1969. Three hundred and fifty patients have died, and 113 were recognized as having central nervous system metastases. The natural history of these metastases was examined, together with the results of a limited number of autopsies. The results of treatment are discussed.
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PMID:Melanoma of the central nervous system. 27 41


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