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

Because some primary tumours often metastasize to the skeleton, their early detection is essential for further therapy and prognosis. Radiographic examination is not sufficiently sensitive for early detection of bone metastases, because it can reveal the typical sign of metastases--decalcification--only after loss of 30-50% of the original amount of calcium from bone tissue (18). Bone scanning with bone-seeking radiopharmaceuticals represents a viable technique for early detection of bone lesions, especially early metastatic disease. The indication for this examination is undoubtedly in breast cancer, cancer of prostate, lung, thyroid gland, hypernephroma, melanoma, plasmocytoma and malignant lymphomas. After good clinical experience of the authors with bone scanning in detection of secondary bone tumours in known primary localisations (9, 14, 15, 10), they tried to elaborate in this paper indicative criteria for bone scanning in patients with suspicious secondary tumourous lesions by unknown primary localisations.
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PMID:Experiences with bone scanning in differential diagnosis of local bone lesions. 624 74

The biochemical and biophysical roles of extracellular calcium ions in HVJ (Sendai virus)-induced cell fusion were studied. (1) Various kinds of cell, such as Ehrlich ascites tumor cells, mouse melanoma cells (B16-CW1 cells) and human epidermoid carcinoma cells (KB cells), could fuse in Ca2+-free medium containing a cheletor, glycoletherdiaminetetraacetic acid, in the same way as in Ca2+-containing medium. (2) The ATP content in Ehrlich ascites tumor cells decreased rapidly when the cells were treated with the virus in Ca2+-free medium but not in Ca2+-containing medium. (3) Intracellular adenine nucleotides leaked out into the reaction medium when the cells were treated with the virus in Ca2+-free medium but not in Ca2+-containing medium. (4) On addition of the virus, O2 consumption of Ehrlich ascites tumor cells decreased in Ca2+-free medium, but not in Ca2+-containing medium. (5) HVJ (Sendai virus) did not affect production of lactate by Ehrlich ascites tumor cells in both Ca2+-free medium and Ca2+-containing medium. These observations suggest that the role of extracellular Ca2+ in virus-induced cell fusion is to maintain the ATP and other intracellular metabolite contents at normal levels instead of triggering the fusion reaction itself.
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PMID:The role of extracellular calcium ions in HVJ (Sendai virus)-induced cell fusion. 625 May 92

Receptors for 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] have been described in several human breast cancer cell lines and more recently in human melanoma. The presence of 1,25-(OH)2D3 receptor (1,25-DR) in two cultured breast cancer cell lines was associated with receptors for calcitonin, another hormone thought to have effects on calcium handling. Therefore, it seemed important to examine a range of established human cancer cell lines for the presence of receptors for 1,25-(OH)2D3 and calcitonin. Thirty-three cancer cell lines were examined. 1,25-DR was found to be present in 23 lines, while calcitonin receptors were not detected in any of them. The 1,25-DR from several cell lines sedimented at about 3.5S in sucrose density gradients, had the appropriate specificity for vitamin D metabolites, had Kds of 0.8 to 2.2 x 10(-11) M, and had receptor concentrations of 12 to 99 fmol/mg protein. Ten malignant melanoma and nine colonic carcinoma lines constituted the largest groups of carcinoma cell lines, and seven and eight, respectively, of these were 1,25-DR positive. The high frequency of 1,25-DR positivity in the cultured colonic carcinoma cells is quite different from the low frequency of 1,25-DR in primary colonic carcinomas. It was also interesting that both of two cell lines derived from patients who had had both bone metastases and malignant hypercalcemia were 1,25-DR positive. These various cell lines may provide useful models for the examination of 1,25-(OH)2D3 action in vitro.
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PMID:Presence of 1,25-dihydroxyvitamin D3 receptors in established human cancer cell lines in culture. 627 75

Mouse B16 melanoma extracts of both cultured cells and tumour tissue contain cyclic AMP phosphodiesterase activity, with 95% present in the soluble fraction. Although activation of the enzyme by added calmodulin did not occur, it was found that endogenous calmodulin was present at a level sufficient to activate fully the enzyme. The ability of Ca-calmodulin to stimulate cyclic AMP phosphodiesterase in this tissue was shown by the inhibitory effect of N-(6-aminohexyl)-5-chloronaphthalenesulphonamide (W7), a known calmodulin antagonist; by the activation of the enzyme with exogenous calmodulin observed in supernatants depleted of endogenous calmodulin by passage over fluphenazine-Sepharose 6B in the presence of Ca2+; by the Ca-dependent binding of the enzyme to calmodulin-agarose and its activation by Ca-calmodulin after elution from the column with EGTA-containing buffer. It was calculated that about 50% of the total cyclic AMP phosphodiesterase activity was calmodulin-activated in this tissue.
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PMID:Calmodulin activation of cyclic AMP phosphodiesterase in the B16 mouse melanoma. 633 2

The effect of Ca2+, Cd2+, Cu2+, Mg2+ and Zn2+ as acetates (10(-3) - 10(-5)M) and of 2% DMSO on the proliferation and differentiation of clone M3 of the Cloudman S91 mouse melanoma was studied and compared with the behaviour of GPK (keratocyte) and MRC5 (fibroblast) cell lines. Whereas neither calcium nor magnesium ions influenced the proliferation of the cells as measured by [3H]-thymidine incorporation, absorbance at 280 nm of NaOH cell digests and cell counts, cadmium, zinc and copper ions selectively inhibited the melanoma line. Cd2+ (10(-5)M) and Zn2+ (10(-4)M) were selectively cytotoxic to melanoma cells in contrast to keratocytes and fibroblasts. No direct effect of the cations on melanogenesis, as estimated from the ratio of absorbance at 350 nm and 280 nm and by tyrosinase assays, was demonstrated. DMSO stimulated melanogenesis in melanoma cells but inhibited their growth. Experiments with ouabain indicate that active transport is involved in the uptake of zinc by melanoma cells.
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PMID:The effect of divalent cations on Cloudman melanoma cells. 668 80

Cultured cell lines LL, B16, C26, and C38 established from mouse solid tumors of Lewis lung carcinoma, B16 melanoma, and colon adenocarcinomas 26 and 38, respectively, showed inherently different resistance to vincristine (VCR) in vitro. The inherent resistance to VCR of these cell lines was related to the ability of the cells to accumulate VCR. Verapamil, a calcium antagonist with coronary vasodilator activity, enhanced the cytotoxicity of VCR against these cell lines depending upon their susceptibility to VCR. C26 cells, the most resistant, became the most susceptible to VCR with a nontoxic dose of verapamil. A 12-fold increase in VCR cytotoxicity occurred. Only a 2.5-fold increase in VCR cytotoxicity was observed for B16 cells, the most sensitive cells. VCR cytotoxicity against each cell line reached almost the same level by verapamil (2.2 to 6.6 microM). Thus, the inherent resistance to VCR among the tumor lines was circumvented. Verapamil enhanced the cellular accumulation of VCR. A 3- to 4-fold increase in cellular VCR occurred in C26 cells, while approximately a 2-fold increase was observed for B16 and LL cells. A similar rate of enhancement was observed for both bound and free VCR, indicating that verapamil does not enhance the affinity of VCR to tubulin. Verapamil inhibited the outward transport of VCR from the cells. The most prominent inhibition was observed for C26 cells. Circumvention of inherent resistance of tumor cells to VCR by verapamil could be attained through an enhanced cellular accumulation of VCR in each of the tumor cells. The enhancement of VCR cytotoxicity and circumvention of inherent VCR resistance by verapamil could be explained by the cellular concentration of VCR, and also it might be related to the extent of VCR binding to tubulin in the cell. The chemotherapeutic effect of VCR is significantly enhanced by verapamil in colon adenocarcinoma 26-bearing mice.
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PMID:Promotion by verapamil of vincristine responsiveness in tumor cell lines inherently resistant to the drug. 684 94

Uveal Greene melanoma was produced in the anterior chamber of 47 eyes in 29 rabbits. One group of rabbits was untreated and served as controls. One group was treated with carmustine (1,3-bis(2-chloroethyl)-1-nitro-sourea; BCNU) intravenously and one group was treated with BCNU both intravenously and locally via an implanted silicone device. Tumor specimens were studied histopathologically with light and electron microscopy. Compared with controls, the treated tumors were smaller, more necrotic, and contained more spindle-shaped cells intermingled with inflammatory cells. Changes were particularly striking in the combined-treatment group. Treated tumors of both groups also showed less invasion into surrounding ocular tissues. Morphologic changes after treatment included the development of numerous degenerative tumor cells with calcium deposition, fragmentation of nuclei, degeneration of mitochondria, accumulation of fat droplets, and disorganization of cytoplasm. These changes may indicate that the drug, particularly following combined delivery, has a cytotoxic effect directly on the tumor cells.
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PMID:Histopathologic changes following carmustine treatment of uveal Greene melanoma in rabbits. 685 49

Despite having lower cell membrane potentials, four human melanoma cell lines and HeLa cells accumulated the membrane probe triphenylmethylphosphonium ion (TPMP, 2 microM) 2-10 fold more rapidly than human fibroblasts, and did not reach equilibrium during the 2 h incubation period studied. The difference was not due to drug toxicity, although at much higher levels of TPMP (greater than 20 microM) selective killing of melanoma cells compared with fibroblasts was observed. Some dependence of TPMP accumulation upon membrane potential was indicated by inhibition of uptake in fibroblasts depolarised by culture in calcium-deficient medium. Melanoma cells exhibited no change in TPMP uptake or membrane potential under these conditions. Uptake of safranine, an indicator of mitochondrial membrane potential, did not follow the TPMP pattern. Thus, the anomalous accumulation of TPMP by human tumour cells appeared to result from either carrier-mediated transport or rapid intracellular metabolism and could not be used to determine cell membrane potentials.
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PMID:Uptake and toxicity of safranine and triphenylmethylphosphonium ion in human tumour cells. 687 Jun 74

Two hundred abnormal bone scans of patients with a malignant melanoma were reread in a blinded fashion to identify osseous metastases. These findings were compared with serum calcium and alkaline phosphatase levels, skeletal surveys and survival curves of the same patients. Thirty-four of the 38 patients classified as positive for osseous metastases by bone scans ultimately supported that diagnosis. Three patients have probable, but not proved, osseous metastases, and one patient is classified as false-positive. Identification of osseous metastases by skeletal surveys never preceded bone scan identification. Skeletal surveys were most helpful in the identification of a benign condition which caused scan positivity. Serum calcium and alkaline phosphatase levels were never as sensitive or specific as either scans or surveys. In two patients with progressive osseous disease, the levels fell. We believe that radionuclide bone scans should be the first diagnostic procedure for suspected osseous metastases in patients with a malignant melanoma. It appears to be a more sensitive and specific test than skeletal surveys or serum calcium and alkaline phosphatase levels. We believe its use as a first test would save time, money and needless surgical procedures.
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PMID:The role of bone scans in assessing malignant melanoma in patients with stage III disease. 738 83

The weight and degree of calcification of 500 pineal glands has been measured. The degree of cellularity, the size of the pineocyte nuclei and the extent of degeneration has been estimated in histological examinations of the glands. There are some differences in the weight of the gland in males and females of different ages and part of this is due to variations in the amount of calcium in the glands. There is only a minor decrease in the cellularity of the glands with increasing age, and this is accompanied in females by a slight increase in fibrosis and gliosis. The weight of the gland is high in patients dying from trauma and burns. No statistical differences are found in the weight of the pineal glands from patients dying of malignant and non-malignant conditions, although in most age-groups the glands tend to be smaller in patients dying of malignancy. On the other hand patients dying from carcinoma of the breast and from melanoma have much larger glands than those dying from sarcoma.
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PMID:The human pineal gland in malignancy. 741 Nov 37


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