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

B16 mouse melanoma cells in monolayers may be satisfactorily fused with 50% PEG 1500. However, pre-treatment with detergents in solution at low concentrations significantly increases PEG fusion, up to 8-fold in some instances, without impairing cell viability. The practical and mechanistical implications of this finding are discussed.
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PMID:Surfactant enhancement of polyethyleneglycol-induced cell fusion. 259 1

Modification of recombinant human interleukin 2 (rhIL-2) with monomethoxy polyethylene glycol has been shown to alter its pharmacokinetic properties. Therefore, we investigated the pharmacological parameters of schedule and dose in order to assess the impact on the in vivo antitumor activity of this modification. The antitumor efficacy, as well as the toxicity, of polyethylene glycol-interleukin 2 (PEG-IL-2) was compared to that of rhIL-2 in three transplantable syngeneic murine tumor models, Meth A fibrosarcoma, B16 melanoma, and Pan-02 pancreatic carcinoma. At equitoxic dose levels, the antitumor activity of PEG-IL-2 was far superior to that of rhIL-2 in all three tumor models. This efficacy of PEG-IL-2 was dose dependent and was greatest on a Q7D x 2 schedule in Meth A and B16. When the same total doses were further divided and delivered on any of several alternative schedules, either the efficacy was reduced or the toxicity of the treatments was increased. In Pan-02, a rhIL-2-resistant tumor, PEG-IL-2 treatment on either the Q7D x 2, Q4D x 3, or Q3D x 4 schedule resulted in approximately a 200% increase in lifespan; however, the toxicity of the treatment increased as the interval between doses was shortened. Simulations of the pharmacokinetic profiles of these various regimens suggested that the toxicity of PEG-IL-2 and rhIL-2 was related to the minimum plasma concentration that was obtained and the time interval between peak levels. The efficacy of the treatment was associated with the interleukin 2 plasma peak height, since a dose response was observed; however, peak plasma concentration did not appear to be the only parameter which determined efficacy. We hypothesize that this observed schedule dependence is also affected by the kinetics of the host's biological response to rhIL-2.
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PMID:Schedule dependency of the antitumor activity and toxicity of polyethylene glycol-modified interleukin 2 in murine tumor models. 281 8

We have attempted to rescue presumptive human endogenous retrovirus(es) by using a competent animal oncovirus as a helper. Human melanoma cells (line HMB2) were fused, using polyethylene glycol, with mouse NIH-3T3 cells which had been infected and transformed by the Harvey murine leukaemia and sarcoma virus complex (MLV and MSV). The heteropolykaryons obtained were co-cultivated with fresh NIH-3T3 cells; filtered (Millipore 0.22 micron) medium from these was used to infect further NIH-3T3 cells. In these cells after several passages, vesicular stomatitis virus (VSV) pseudotypes could be produced. These were infectious not only for mouse cells (manifesting the helper MLV), but also for human cells (HeLa, HEC human embryo fibroblasts, HMB2); they were not infectious for CCL64 (mink) or for Vero (African green monkey) cells. The presence of such VSV pseudotypes infectious for human cells indicated that a human ecotropic virus [provisionally named rescued human virus (RHV)] had been rescued by the fusion of human melanoma cells with MLV-infected mouse cells. This was supported by the following evidence. The human-specific pseudotype was neutralized by sheep antisera raised to antigens selected by VSV from human tumour cell lines HMB2, T47D and HeLa. These antisera also aggregated NIH cells infected with MLV and RHV. Mouse antisera raised to antigens present in HIH cells infected with MLV and RHV, in contrast to sera raised to NIH cells infected with MLV only, immunoprecipitated an 85,000 mol. wt. protein band from human cells (HEC, HMB2 and HeLa) surface-labelled with 125I.
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PMID:Rescue of presumptive viral information from human cells by a helper oncovirus. 301 51

A pilot study was performed to test for melanoma-associated antigens (MAAgs) in the sera of patients with localized uveal melanoma, using monoclonal antibodies (MoAbs). Both whole sera and polyethylene glycol (PEG) 2.5% serum precipitates from 18 patients with clinically localized uveal melanoma and two patients with localized invasive conjuctival melanoma were analyzed for two human cutaneous MAAgs by an enzyme-linked immunosorbent assay (ELISA). These antigens could not be identified when whole sera were used. However, after PEG precipitation, a MoAb specific for the p210 MAAg reacted with four of 20 patient samples and none of 17 controls. A second MoAb specific for the p97a MAAg reacted with one of 20 patients and none of 17 controls. These findings indicate the existence of antigens common to both uveal and cutaneous melanoma and suggest that the refinement of assays to screen sera with a battey of MoAbs may be of value in diagnosing and/or monitoring patients with uveal melanoma. Circulating immune complexes were detected in the sera of six patients but did not correlate with any clinical features or with the presence or absence of detectable MAAgs.
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PMID:Circulating melanoma-associated antigens in ocular melanoma. 340 88

A polyethylene glycol precipitation technique was used to determine the levels of circulating immune complexes (CIC) in breast cancer and melanoma patients. All patients in the study had undergone surgery and were free of distant metastatic disease. CIC were measured at two to four time intervals, of 3 to 6 months each, over an average follow-up period of 13.5 months (range 7-20 months). In both groups of patients, metastatic disease developed with a higher frequency in patients who had undetectable CIC levels throughout the follow-up period or had become negative at the time metastases were discovered.
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PMID:Serial circulating immune complex values and development of metastatic disease in breast cancer and malignant melanoma patients. 351 30

Due to their specificity, constant properties and virtually unlimited supply monoclonal antibodies have given an important stimulus to almost every field of biomedical research within the last 10 years. The generation of mouse monoclonal antibodies includes immunisation of mice followed by fusion of mice spleen cells with a murine myeloma cell line. With this procedure hybridomas secreting monoclonal antibodies of a predefined specificity can be obtained. For three major reasons we worked on the establishment of human hybridomas secreting specific antibodies: human antibodies are less immunogenic when used for diagnostic or therapeutic purposes, only human monoclonal antibodies allow the analyses of the human B cell repertoire, there is evidence that human monoclonal antibodies recognise epitopes different from those seen by murine monoclonal antibodies. Therefore, we set out to generate human B cell hybridomas by cell fusion using the human lymphoblastoid B cell line Wi-L2-729 HF2 and lymphocytes from melanoma patients. The lymphocytes were isolated from tumour-draining cervical lymph nodes, stimulated with pokeweed mitogens plus the autologous tumour cells in an enriched tissue culture medium and fused in the presence of polyethylene glycol. Supernatants of hybridomas were screened in a single cell immunosorbent assay with either autologous melanoma cells or established melanoma cell lines fixed to the bottom of Terasaki plates or on cytospin preparations of these cells using the immunoperoxidase staining procedure. We could demonstrate that the tumour draining lymph nodes of these melanoma patients contained B lymphocytes capable of producing antibodies reacting with the tumour cells.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Attempts to produce human monoclonal antibodies to melanoma using the cervical lymph nodes]. 358 98

We evaluated the ability of repeated measurements of circulating immune complexes (CIC) to predict for tumor recurrence in 130 patients with malignant melanoma. Twenty-two patients had level 2, 45 had level 3, and 51 had level 4/5, stage I disease in remission at the start of monitoring, while 12 had stage II disease. The polyethylene glycol precipitation assay was used for serial studies, based on an initial comparative evaluation with the Clq-binding and Raji assays. The study averaged 22 +/- 11 months (6-43 months) and an average of 22 +/- 5.3 assays were performed per patient (range 3-36), with a follow-up of 4 years. CIC were present in sera in recurrent, irregular 'bursts' of activity. Serial measurements doubled the incidence of CIC compared to single determinations. Only 23% of these bursts of activity were clearly related temporarily to documented recurrences, while 34% occurred with treatment events such as surgery or immunotherapy, and 42% occurred without correlation to either recurrence or treatment. CIC activity was greater and more closely related to recurrence in high-risk stage I (level 4,5) and stage II patients. Whether analyzed as positive sera or as bursts of elevated CIC activity, CIC assays predicted for recurrence at the 5% significance level. The assay was highly sensitive (97%), but with poor specificity (21%) with many false positives (79%). The assay was helpful at ruling out recurrences (95%), but poor at ruling them in (29%). The advantage was seen only in high-risk stage I and II patients, and there was no advantage to serial assays over random single determinations. Although generally, CIC in the sera of melanoma patients were found to predict for recurrence, the use of serial CIC measures monitoring of individual patients cannot be recommended.
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PMID:Circulating immune complexes in malignant melanoma: serial studies in 130 patients. 370 59

The establishment of functional human cytotoxic T lymphocyte (CTL) hybrids was investigated. Human CTL, generated in a seven-day, one-way mixed lymphocyte-tumor cell interaction (MLTI) against an allogeneic melanoma cell line (DW) in the presence of a third-party helper cell line and crude interleukin 2 (IL2), were fused with a mouse myeloma cell line (P3-X63 Ag8). Following fusion in polyethylene glycol, the hybrids were examined for cytotoxic potential against the sensitizing target cells DW. Hybrids with detectable levels of cytotoxicity were cloned in soft agar. Two clones demonstrating stable activity were selected for analysis of lineage and specificity of cytotoxicity. Both clones expressed cytotoxicity in a reasonable stable manner without dependence on IL2 for growth or function. Interferon had no effect on the cytotoxicity of the hybrids against the natural killer (NK)-sensitive target cells K562 or the DW cells. The cytotoxic activities of the hybrids against the sensitizing target cells DW, however, could be markedly facilitated in the presence of IL2-containing supernatants in the assay medium and less so in the presence of lectin. The range of the cytotoxic activities of the two clones was identical and restricted to the DW cells and another melanoma cell line, suggesting the possibility of a shared target molecule(s) between these two target cells for these cytotoxic hybrids. These observations indicate that the hybrids might require a mediator present in IL2 supernatant for optimum expression of cytotoxicity and suggest that the hybrids express the cytotoxic specificity of the hybridized CTL. These hybrids offer unique opportunities for critical examination of the molecular mechanisms of cellular cytotoxicity and specificities exhibited by activated human CTL.
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PMID:Functional hybrids between human cytotoxic T and mouse myeloma cells. 633 59

In the experiments reported here, I was unable to detect any fusion between host cells and transplanted tumor cells; however, spontaneous hybridization between tumor cells appears to occur in the B16 melanoma. This hybridization was demonstrated by mixing together B16-F10RR cells (universal fusers) and B16-F10 cells, allowing them to grow in close juxtaposition, and recovering putative hybrids in the appropriate selection media. The tumor cell-tumor cell composition of the resultant hybrids is inferred from the relative frequency of fusions, compared with the infrequency of tumor cell-host cell fusion when single populations of B16-F10RR cells were used, and by the chromosomal content of the hybrids. Definitive proof that hybridization occurs between both types of tumor cell rather than between a tumor cell and some other type of cell would require the use of a third biochemical marker on the unmarked tumor cells. I am now repeating these experiments using B16-F10 cells that exhibit resistance to the neomycinlike antibiotic G418. Nonetheless, it is not surprising to find that such closely related tumor cells fuse with one another. The efficiency of in vitro hybridization mediated by polyethylene glycol is increased when the hybridizing cells are histologically or developmentally related, so that B16 melanoma cells fuse more readily with one another than they do with unrelated cells such as UV-2237 cells (I. Hart, unpublished observations). Moreover, early hybridization protocols did not call for the use of fusogens, but merely the cocultivation of participating cells in the two-dimensional constraints of a tissue culture dish (e.g., Barski et al. 1961, Silagi 1967). Presumably, the increased contact between cells within a growing tumor mass would increase the likelihood of such spontaneous fusion. In vivo hybridization could play a significant role in neoplastic progression and variation in metastatic efficiency by at least two separate, but not necessarily mutually exclusive, mechanisms. First, fusion of two contiguous tumor cells would increase the chromosome content of the resultant single cell; this increase in ploidy could facilitate and heighten the apparent inherent genetic instability of neoplastic cells (Nowell 1976). Although segregation and chromosome loss may or may not be random or preferential in nature (Campbell and Worton 1981), the mere occurrence of such a phenomenon could also cause chromosomal disjunction and the possible extinction and reexpression of specific genes, which would lead to the independent variation and progression of different tumor cell characteristics in the manner cited by Foulds (1969).(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Tumor cell hybridization and neoplastic progression. 638 3

Different procedures for fixation and processing were evaluated in order to examine the antigenic profile of melanocytes and other epidermal cells for immunoelectron microscopy. For this purpose the monoclonal antibodies anti-HLA-A, B, C, anti-HLA-DR, anti-T6, and the melanoma-associated monoclonal antibody NKI /C-3 were used as markers. Fixation with periodate-lysine-paraformaldehyde yielded better antigenic and ultrastructural preservation than 3% paraformaldehyde or picric acid-paraformaldehyde did. Skin was further processed by five different methods: (a) 15-micron frozen sections; (b) 75-micron agar-embedded, tissue chopper sections; (c) 15-micron polyethylene glycol-embedded sections; (d) epidermal cells in suspension; and (e) epoxy sections (postembedding staining) were prepared for the immunoperoxidase procedure. Antigenicity was best preserved in the cell suspension method and somewhat less, but with a similar staining distribution, with the first three methods. Staining with the polyethylene glycol-embedded sections was only achieved if they were left free-floating in buffer; no staining was observed when the sections were mounted on glass slides and left to dry overnight at 37 degrees C. Epidermal cells remained unreactive in the postembedding method, even after etching. Ultrastructural preservation of the agar-embedded sections and the cells in suspension was superior to the other preembedding methods. Melanocytes mostly showed moderate staining for HLA-A, B, C and slight staining for the antigen that is recognized by NKI /C-3. The latter was further demonstrated on Langerhans cells and indeterminate cells which also expressed HLA-A, B, C, T6, and HLA-DR antigens.
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PMID:Methods in laboratory investigation. Immunoelectron microscopic methods for demonstration of antigens on normal human melanocytes and other epidermal cells. 642 21


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