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

Freeze-fracture negative staining methods were used to investigate the structure of melanosomes isolated from B16 melanoma. The findings demonstrated the presence of a melanosomal double-layered membrane. Negative staining procedure showed that the melanosomal membrane is sometimes ruptured, displaced or peeled off during the purification process. Fractured melanosomes showed melanin spheres with a mean diameter of 24 nm. This compares with a mean diameter of 26 nm for the melanin spheres revealed by negative staining. The granular appearance of fractured mature melanosomes is due to the fracture following a random path between melanin spheres.
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PMID:The use of freeze-fracture and negative staining techniques to study the ultrastructure of melanosomes isolated from B16 melanoma. 125 24

To optimize skin pigmentation in order to help body prevention against UV radiation, the mechanism of melanin pigment transfer from melanocytes to keratinocytes must be elucidated. Melanin transfer to keratinocytes requires specific recognition between keratinocytes and melanocytes or melanosomes. Cell surface sugar-specific receptor (membrane lectin) expression was studied in human C32 melanoma cells, an amelanotic melanoma, by flow cytometry analysis of neoglycoprotein binding as an approach to the molecular specificity. Sugar receptors on melanocytes are mainly specific for alpha-L-fucose. Their expression is enhanced upon treatment by the diacylglycerol analogue 1-oleoyl-2-acetylglycerol, which can induce melanin synthesis in amelanotic human melanoma cells in a dose-dependent manner. Flow cytometry analyses showed a small-sized population of vesicles distinguishable from large cells by their fluorescence properties upon neoglycoprotein binding. Sorting indicated that the small-sized subpopulation is composed of vesicles produced by melanocytic cells. Upon vesicle formation, a selective concentration of sugar receptors specific for 6-phospho-beta-D-galactosides appears in the resulting melanocytic vesicles. Vesicles are recognized and taken up by cultured keratinocytes and a partial inhibitory effect was obtained upon cell incubation in the presence of neoglycoproteins, indicating a possible participation of sugar receptors in this recognition. The validity for such a model to help in understanding the natural melanin transfer by melanosomes is confirmed by electron microscopy, which demonstrates the presence of melanin inside keratinocytic cells upon incubation with melanocytic vesicles.
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PMID:C32 human melanoma cell endogenous lectins: characterization and implication in vesicle-mediated melanin transfer to keratinocytes. 142 39

The N-linked sugar chains of melanoma cell membrane from five murine B16 melanoma clones (F1, F10, BL6, W1-4, and C4-1) with different degrees of metastatic abilities after intravenous and intrafootpad injections were released quantitatively as oligosaccharides by hydrazinolysis, and their structures were analyzed by serial lectin column chromatography, Bio-Gel P-4 column chromatography, and sequential glycosidase digestion. Sugar chain structures of each clone have shown to consist of the same elemental oligosaccharides, but to differ in their percent compositions. More than 84% of the neutral oligosaccharides were high mannose-type sugar chains. Most complex-type sugar chains were sialylated, of which the major structure was tetraantennary sugar chain. Highly lung-colonizing F10 cells had 1.4 and 1.7 times more non-repeated tetraantennary sugar chains than moderately colonizing F1 and C4-1 cells, respectively, and 2.5 times more than poorly colonizing W1-4 cells. BL6 cells, which are also highly lung-colonizing, had 1.5 and 1.9 times more non-repeated tetraantennary sugar chains than F1 and C4-1 cells, respectively, and 2.8 times more than W1-4 cells. These results suggest that increase of sialylated tetraantennary complex-type sugar chains without N-acetyllactosamine repeating units of B16 melanoma cells might correlate with the higher lung-colonizing ability after intravenous injection.
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PMID:Increase of sialylated tetraantennary sugar chains in parallel to the higher lung-colonizing abilities of mouse melanoma clones. 194 Apr 47

Mortality was studied among 1271 employees of a cellulose fiber production plant in Rock Hill, South Carolina, in the United States. Each subject was employed for at least three months between 1 January 1954 and 1 January 1977 in jobs that entailed exposure to the highest concentrations of methylene chloride. In the cohort 122 deaths were identified through 1 September 1986, and mortality rates for the cohort were compared with mortality rates for York County, South Carolina. Deficit mortality was observed for cancers of the respiratory system, breast, and pancreas and from ischemic heart disease. Excess mortality was observed for cancers of the buccal cavity and pharynx and the liver and biliary tract, and for melanoma as well. The largest relative excess was for liver and biliary tract cancers. There were only four deaths in this category; however, three of the four deaths were cancer of the biliary tract (3 observed, 0.15 expected, standardized mortality ratio 20).
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PMID:Mortality of cellulose fiber production workers. 238 31

The clinical features of the most common bluish and pigmented lesions of the oral mucosa are discussed in this paper. Considerable attention is given to the findings from the medical and dental history of the patient, in the methodology of the clinical examination (inspection, palpation, digital pressure, aspiration) in the clinical characteristics of the lesions (location, size duration, consistency, prognosis) in the laboratory findings (radiographs and other supplementary examinations) and in the differential diagnosis. The bluish and pigmented lesions which are discussed include: melanoma, Albright's syndrome, Addison's diseases, Peutz-Jeghers's syndrome, arsening poisoning, hemangioma, hematoma, petechia and ecchymosis, Sturge-Weber syndrome, amalgam tatoo, heavy metal lines, mucocele and eruption cyst.
Hell Stomatol Chron
PMID:[Differential diagnosis of bluish and pigmented lesions of the oral mucosa]. 251 53

Melanoma most often develops in the skin; usually at the site of a preexisting nevus. It is quite rare in the oral cavity and the maxilla is the most common location there. It appears that males between 60 and 70 years old are affected more often than females. The etiology is unknown. However the melachromatic nevus and the color of the skin are considered predisposing factors. Based on clinical and histologic criteria it is classified in three categories. Unfortunately the frequency of the occurrence of each category into the mouth separately, is inversely proportional to the prognosis. The 5 year survival rate of intraoral melanoma does not exceed 5-9%. The treatment of melanoma is surgical and comprises radical excision of the lesion and radical neck dissection. Radiotherapy and chemotherapy do not seem to contribute to the treatment. We present our experience of two patients with melanoma of the maxilla. In one case submandibular lymphadenopathy had already been established and a radical neck dissection was performed. In the other case subtotal maxillectomy was performed with intraoral approach.
Hell Period Stomat Gnathopathoprosopike Cheir 1989 Mar
PMID:[Primary melanoma of the oral cavity]. 264 Jun 48

31P nuclear magnetic resonance spectra of human melanoma (BRO) cells implanted in nude mice were obtained both in vitro and in vivo. The tumors were allowed to grow in the right axillary region of six adult Swiss nude mice to a transverse diameter of 1.5-2 cm, at which point the in vivo 31P nuclear magnetic resonance spectra were obtained. The animals were subsequently sacrificed and the tumor perchloric acid extract was studied in vitro. Relative peak areas are comparable in the two experiments with the exception of inorganic phosphate, which is more abundant in vivo than in vitro by a factor of 4. This difference may be attributed to a greater contribution of the necrotic portion of the tumor to the in vivo spectra. Resonance peaks in the spectrum of the extract were identified on the basis of their coincidence with standards added at pH 7 and 10. Non-energy phosphorylated metabolites present in the tumor at high levels include phosphoethanolamine, phosphocholine, glycerol phosphocholine, and uridine-5'-diphospho-N-acetyl glucosamine. Sugar phosphates and 2,3-diphosphoglycerate from blood made minor contributions to the spectrum. The tumor also contained substantial amounts of pyrimidine triphosphates accounting for 34% of the total nucleoside triphosphate pool.
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PMID:Characterization of the 31P nuclear magnetic resonance spectrum from human melanoma tumors implanted in nude mice. 362 Nov 91

The ability of a member of a new class of lipophilic muramyl dipeptide (MDP) derivative, muramyl dipeptide-glyceryldipalmitate (MDP-GDP), to induce alveolar macrophage cytotoxic activity in vitro towards B16 melanoma cells when incorporated into two types of liposome was studied. MDP-GDP incorporated into conventionally prepared liposomes formulated from distearoylphosphatidylcholine and phosphatidylserine (7:3 molar ratio) was 10-fold more effective than liposomes containing MDP, and 7000-fold more effective than free MDP in inducing macrophage cytotoxic activity. MDP-GDP incorporated into freeze-dried liposomes was 50,000- to 100,000-fold more effective than free MDP in inducing such activity. Freeze-dried liposomes containing MDP-GDP were efficiently localized in the lungs of normal mice, and induced cytotoxic activity in the alveolar macrophages. Such liposomes were able to significantly reduce the pulmonary metastatic burden of mice carrying the B16 melanoma. These data provide evidence that this class of lipophilic MDP derivative, when incorporated into freeze-dried liposomes, is a potent inducer of macrophage cytotoxic activity in vitro and in situ, and has antitumor activity in vivo. In addition, the use of a freeze-drying procedure allows the preparation and long-term storage of reproducible liposome formulations.
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PMID:Activation of alveolar macrophage tumoricidal activity and eradication of experimental metastases by freeze-dried liposomes containing a new lipophilic muramyl dipeptide derivative. 383 84

The accompanying article (Manzi, A., Salimath, P. V., Spiro, R. C., Keifer, P. A., and Freeze, H. H. (1995) J. Biol. Chem. 270, 9154-9163) reported the complete structure of a novel molecule made by human melanoma cells incubated with 1 mM 4-methylumbelliferyl-beta Xyl (Xyl beta MU). The product resembles a common pentasaccharide core region found in chondroitin/dermatan sulfate glycosaminoglycans, except that a terminal alpha-Gal-NAc residue is found in a location normally occupied by beta-GalNAc in these chains or alpha-GlcNAc in heparan sulfate chains. In this paper we show that several other human cancer cell lines and Chinese hamster ovary cells also make alpha-GalNAc-capped xylosides. The [6-3H]galactose-labeled Xyl beta MU product binds to immobilized alpha-GalNAc-specific lectin from Helix pomatia and the binding is competed by GalNAc, but not by Glc. Binding to the lectin is destroyed by digestion with alpha-N-acetylgalactosaminidase, but not beta-hexosaminidase. The nature of the aglycone influences the amount and relative proportion of this material made, with p-nitrophenyl-beta-xyloside being a better promoter of alpha-GalNAc-terminated product than Xyl beta MU. This novel oligosaccharide accounts for 45-65% of xyloside-based products made by both human melanoma and Chinese hamster ovary cells when they are incubated with 30 microM Xyl beta MU, but at 1 mM both the total amount and the proportion decreases to only 5-10%. In both cell lines this product is replaced by a corresponding amount of Sia alpha 2,3Gal beta 4Xyl beta MU. Preferential synthesis of the alpha-GalNAc-capped material at very low xyloside concentration argues that it is a normal biosynthetic product and not an experimental artifact. This pentasaccharide may be a previously unrecognized intermediate in glycosaminoglycan chain biosynthesis. Since this alpha-GalNAc residue occurs at a position that determines whether chondroitin or heparan chains are added to the acceptor, it may influence the timing, type, and extent of further chain elongation.
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PMID:Identification of a novel glycosaminoglycan core-like molecule. II. Alpha-GalNAc-capped xylosides can be made by many cell types. 772 31

In our efforts to produce monoclonal antibodies that recognize cell-surface antigens expressed by hematopoietic precursor and stromal cells, we generated a monoclonal antibody, 7.1, which recognizes a 220- to 240-kD cell-surface protein whose N-terminal amino acid sequence is identical to the rat NG2 chondroitin sulfate proteoglycan molecule. This chondroitin sulfate proteoglycan, previously reported to be expressed by human melanoma cells, was not found to be expressed by normal hematopoietic cells, nor was it expressed on the cell surface of cell lines of hematopoietic origin including cell lines with 11q23 abnormalities. It was found on the cell surface of acute myeloid leukemia (AML) blasts and cell lines derived from nonhematopoietic tissues. Samples of leukemic marrow from 166 children with AML enrolled on Childrens Cancer Group protocol 213 were evaluated for cell-surface expression of this proteoglycan molecule. In 18 of 166 (11%) patient samples, greater than 25% of leukemic blasts expressed the NG2 molecule. These 18 patients had a poorer outcome with respect to survival (P = .002) and event-free survival (P = .035) with an actuarial survival at 4 years of 16.7%. Blast cell expression of the NG2 molecule was strongly associated with French-American-British M5 morphology (P < .0001) and abnormalities in chromosome band 11q23, site of the MLL gene. These results show that the NG2 molecule is expressed by malignant hematopoietic cells that have abnormalities in chromosome band 11q23, suggesting that antibody 7.1 may be useful in the rapid identification of this group of poor-prognosis patients.
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PMID:The human homologue of rat NG2, a chondroitin sulfate proteoglycan, is not expressed on the cell surface of normal hematopoietic cells but is expressed by acute myeloid leukemia blasts from poor-prognosis patients with abnormalities of chromosome band 11q23. 856 38


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