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

I am delighted to inform our readership that we have been accepted for inclusion in EMBASE and MEDLINE, the indexing databases of Excerpta Medica and Index Medicus. You are now able to obtain journal article citations commencing with this issue, by searching EMBASE, and in the near future, by searching MEDLINE. Both databases are also accessible through Silver Platter. With continued concern over the increasing incidence of melanoma, this issue of the Journal focuses on a number of important areas related to this subject. In our our Point-Counterpoint editorials, Drs. Frans Rampen and Martin Weinstock evaluate the pros and cons of mass screening programs in a cogent fashion. An ongoing controversy in the treatment of melanoma has been the margin required for optimal excision of the primary lesion. Over the past several decades, there has been a steady reduction in the extent of the resection of the primary tumour. Drs. Beasley and Cartotto retrospectively analyzed over 100 primary melanomas. Two local recurrences were seen in melanomas less than 2 mm thick, despite a margin of 1.7 and 2.4 cm. While larger studies are needed, this analysis stimulates some question on the true safety of currently accepted margins for 1 to 2 mm thick melanomas. Continuing with the theme of melanoma, our Grand Rounds from the University of British Columbia discusses a patient with melanoma and unilateral vascular tumours. In their article on familial melanomas, Hogg et al. review the area of the genetics of melanoma, with particular reference to the role of cyclin dependent kinase inhibitor gene CDKN2A, on chromosome 9p21 and its potential predictive role in identifying at risk individuals for melanoma. I am pleased to have Dr. Robert Jackson introduce a new section in the Journal, Classics in Dermatology. This series provides a historical perspective on dermatologic disease. While the above article on melanoma illustrates how advances in molecular biology have dramatic impacts on our diagnostic skills, as dermatologists we still greatly value accurate clinical skills. The Classics in Dermatology focuses, from a historical perspective, on the importance of clinical acumen. Advances in dermatologic surgery have dramatically transformed our specialty. Hair transplantation was one of the initial areas of dermatologic surgery and dermatologists have been at the forefront of this field since the landmark studies by Dr. Orentreich in 1959. Since that time there have been major changes in the technique of hair transplantation that have greatly enhanced the outcomes. Drs. Bertucci, Berg, and Pollack update us on current techniques in this field.
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PMID:Editorial 947 76

We investigated the cytoadherence of Plasmodium falciparum infected erythrocytes to target cells that express CD36 by soft x-ray microscopy. Using immunogold beads enhanced with silver, we localized CD36 on the surface of intact melanoma cells and throughout Triton extracted melanoma cells. We examined the orientation of parasites within erythrocytes that bound to target cells, and the interactions between the red cell membrane and the target cell, and we confirmed that fibrillar structures on the surface of melanoma and endothelial cells can be involved in the association between infected erythrocytes and melanoma cells or endothelial cells.
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PMID:X-ray microscopic visualization of specific labeling of adhesive molecule CD36 and cytoadherence by Plasmodium falciparum infected erythrocytes. 959 21

The nucleolar organizer regions (NORs) are chromosomal loops of DNA and proteins involved in ribosomal synthesis. By silver staining, they can be identified as black dots (AgNORs) in the nuclei. Their size and number reflect cell and nuclear activity. Therefore, AgNOR count may correlate with the proliferative activity of tumors. In malignant melanoma, correlation between AgNOR count and the growth phase was found. However, the value of AgNORs in determining prognosis is disputable. Our purpose was to evaluate the role of AgNORs in predicting the biological behavior of melanoma. Paraffin-embedded sections of 30 cases of primary melanoma, 0.4-5 mm thick (mean, 1.6 mm) were stained with silver. Follow-up of all patients was at least 5 years. For each tumor, at least 50 cells were randomly selected for AgNOR count at a final magnification of 500, and the mean of AgNOR content was calculated. Sample parameters corresponded well to the epidemiology and the natural history of melanoma. AgNOR counts (0.78-4.26; mean, 1.42+/-0.72) correlated with tumor thickness (p = 0.01); thus, most superficial tumors had low AgNOR counts, whereas most deep tumors (> or = 1.5 mm) showed high counts. Patients who had tumors with AgNOR counts lower than the median had longer disease-free interval (DFI) than did patients who had tumors with higher counts (p = 0.02). Furthermore, in a multivariate Cox analysis, AgNOR count was independent of tumor thickness in determining DFI (p = 0.05). Therefore, AgNORs may serve as a parameter to predict more accurately the progression of melanomas (mainly thin ones). Larger studies are needed in order to consolidate these preliminary results and to characterize AgNOR value further as a prognostic factor in melanoma.
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PMID:Silver-stained nucleolar organizer regions (AgNORs) as a prognostic value in malignant melanoma. 979 Jan 8

We evaluated whether genetic instability, which is the hallmark of cancer cells, can be investigated at the single chromosomal level. We established in culture and examined a human malignant melanoma cell line and its 11 distinct clones as well as peripheral blood cultures from the original patient by G-banding, C-banding, and silver-staining (AgNOR) techniques. There were six marker chromosomes common to most of the 11 clones and eight or nine additional marker chromosomes found in only one or in very few clones. Chromosome 1 had a pericentric inversion in the C-banded region in both the tumor and the lymphocyte metaphase spreads. This same homologue was also involved in the formation of one of the shared marker chromosomes; this marker, in turn, was rearranged to form two unique markers in one clone. Our findings suggest that genetic instability can be studied at the single chromosome level. Moreover, this study further supports our earlier contention that peripheral blood lymphocyte cultures can show chromosomal lesions that are stable markers in cancer cells.
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PMID:Can genetic instability be studied at the single chromosome level in cancer cells? Evidence from human melanoma cells. 997 60

We report the discovery, cloning, and characterization of a novel human matrix metalloproteinase 26 (MMP-26) (matrixin) gene, endometase, an endometrial tumor-derived metalloproteinase. Among more than three million expressed sequence tags sequenced, the endometase gene was only obtained from human endometrial tumor cDNA library. Endometase mRNA was expressed specifically in human uterus, not in other tissues/cells tested, e.g. testis, heart, brain, lungs, liver, thymus, and melanoma G361. Endometase protein has a signal peptide, a propeptide domain, and a catalytic domain with a unique "cysteine switch" propeptide sequence, PHCGVPDGSD, and a zinc-binding motif, VATHEIGHSLGLQH. Endometase is 43, 41, 41, and 39% identical to human metalloelastase, stromelysin, collagenase-3, and matrilysin, respectively. The zymogen was expressed and isolated from Escherichia coli as inclusion bodies with a molecular mass of 28 kDa. The identity and homogeneity of the recombinant protein was confirmed by protein N-terminal sequencing, silver stain, and immunoblot analyses. The pro-enzyme was partially activated during the folding process. Endometase selectively cleaved type I gelatin and alpha(1)-proteinase inhibitor; however, it did not digest collagens, laminin, elastin, beta-casein, plasminogen, soybean trypsin inhibitor, or Bowman-Birk inhibitor. It hydrolyzed peptide substrates of matrixins and tumor necrosis factor-alpha converting enzyme. Endometase may selectively cleave extracellular matrix proteins, inactivate serpins, and process cytokines.
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PMID:Identification and characterization of human endometase (Matrix metalloproteinase-26) from endometrial tumor. 1080 41

The melanosomal proteins encoded by the silver (si, SILV, or PMEL17) locus play important roles in melanogenesis and are actively investigated as targets for melanoma immunotherapy. The human silver locus yields two proteins, gp100 and PMEL17, by alternative splicing of a common mRNA precursor. Mouse melanocytes exclusively express the gp100 orthologue, here termed gp87, thus providing a simpler model with which to study the silver locus products. We have analyzed the effects of [Nle4, D-Phe7]-alpha melanocyte-stimulating hormone (alphaMSH) and two hypopigmenting cytokines, tumor necrosis factor (TNF)-alpha and transforming growth factor (TGF)-beta1, on the expression of gp87 in B16 mouse melanoma cells. TNF-alpha and TGF-beta1 (at saturating doses for 48 hr) decreased gp87 mRNA by 50%. The gp87 protein was almost undetectable by Western immunoblotting after TNF-alpha treatment, but was not affected by TGF-beta1. alphaMSH increased the mRNA and the gp87 protein approximately 2-fold. Moreover, the amount of gp87 was not reduced by TNF-alpha in the presence of the hormone, in spite of a 50%, decrease in its mRNA. Therefore, the levels of mRNA and gp87 protein did not correlate after treatment with the cytokines. Overall, our data suggest that the silver locus product is not regulated exclusively at the transcriptional level, and highlight the importance of still-uncharacterized regulatory translational and/or post-translational events.
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PMID:Regulation of the murine silver locus product (gp87) by the hypopigmenting cytokines TGF-beta1 and TNF-alpha. 1084 Oct 34

The role of ultraviolet (UV) radiation in the induction of nonmelanoma skin cancer is widely accepted, although its precise contribution to the development of primary cutaneous melanoma skin cancer requires further definition. We found that painting aloe emodin, a trihydroxyanthraquinone from Aloe barbadensis, in ethyl alcohol vehicle on the skin of mice in conjunction with exposure to UVB (280-320 nm) radiation results in the development of melanin-containing skin tumors. C3H/HeN mice were treated thrice weekly with aloe emodin in a 25% ethanol in water vehicle and exposed to 15 kJ/m2 UV radiation. Neither ethanol vehicle nor aloe emodin alone induced skin tumors in the absence of UV radiation. In two separate experiments, 20-30% of the mice treated with a combination of UV radiation and ethanol vehicle and 50-67% of the UV-irradiated animals given aloe emodin in ethanol vehicle developed primary cutaneous melanin-containing tumors. The diagnosis of melanoma was established using Fontana silver stain for melanin; these tumors were negative for vimentin and keratin. Melanin-containing melanosomes were observed by transmission electron microscopy in tumors diagnosed as melanomas. Although the mechanism of carcinogenesis in these mice is currently unknown, our findings have led to the development of the first facile murine model for the induction of primary melanoma. This model has the potential to clarify the role of UV radiation in the etiology of malignant melanoma.
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PMID:Induction of primary cutaneous melanomas in C3H mice by combined treatment with ultraviolet radiation, ethanol and aloe emodin. 1098 13

We describe a case of focal argyrosis of the conjunctiva clinically simulating a melanoma. An 82-year-old woman was referred for an asymptomatic pigmented conjunctival lesion. Her only significant past ocular history was strabismus surgery 76 years earlier. Biopsy of the conjunctiva and lateral rectus muscle revealed the discoloration was pigment granules. Energy-dispersive x-ray microanalysis revealed the pigmentation to be silver deposits. The patient had strabismus surgery probably using a silver clip. Argyrosis should be considered in the differential diagnosis of focal pigmented conjunctival lesions.
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PMID:Localized conjunctival argyrosis: a late sequela of strabismus surgery. 1109 29

Treatment of human melanoma cells with the differentiation-inducing agent hexamethylene bisacetamide (HMBA) results in reciprocal changes in expression of melanocyte-specific genes tyrosinase-related proteins-1 and -2 (TYRP1 and TYRP2). In this study, we investigated the effects of HMBA on cultured neonatal human cutaneous melanocytes. Flow cytometric analysis showed that HMBA inhibited 12-O-tetradecanoylphorbol-13-acetate (TPA)-dependent growth of melanocytes by reducing the population of cells entering the DNA synthesis phase of cell cycle. Melanocyte growth inhibition was accompanied by an increase in the number of cells exhibiting polydendritic morphology. This morphologic change was less pronounced when HMBA was added to melanocytes in the absence of TPA. Northern blot analyses of total cellular RNA showed that expression of microphthalmia-associated transcription factor (MITF), tyrosinase (TYR), TYRP1, Silver (SILV/Pmel17) gene was down-regulated by HMBA, while TYRP2 mRNA was up-regulated (> 10-fold). When the inducer was added to cells in the absence of TPA, there was > 50-fold increase in TYRP2 mRNA with a moderate increase in MITF, tyrosinase and SILV gene mRNAs and complete repression of TYRP1 gene. Studies using inhibitors for protein kinases involved in cell signaling pathways suggested that stress-activated kinase p38 and mitogen-activated protein kinase kinase MEK are involved in TPA-independent regulation of TYRP2 expression in melanocytes. These data show that treatment of proliferating melanocytes with the differentiation inducer HMBA results in a distinct change in morphology and up-regulation of TYRP2, while quiescent melanocytes respond by a dramatic increase in expression of TYRP2 without change in morphology. These results suggest an inverse relationship of TYRP2 gene regulatory mechanisms to melanocyte growth regulatory pathways.
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PMID:Regulation of tyrosinase-related protein-2 (TYRP2) in human melanocytes: relationship to growth and morphology. 1131 Jul 93

H(2)O(2) and other reactive oxygen species are key regulators of many intracellular pathways. Within mammalian skin, H(2)O(2) is formed as a byproduct of melanin synthesis, and following u.v. irradiation. We therefore analyzed its effects on melanin synthesis. The activity of the rate-limiting melanogenic enzyme, tyrosinase, decreased in H(2)O(2)-treated mouse and human melanoma cells. This inhibition was concentration- and time-dependent in the B16 melanoma model. Maximal inhibition (50-75%) occurred 8-16 hours after a 20 minute exposure to 0.5 mM H(2)O(2). B16 cells withstand this treatment adequately, as shown by a small effect on glutathione levels and a rapid recovery of basal lipid peroxidation levels. Enzyme activities also recovered, beginning to increase 16-20 hours after the treatment. Inhibition of enzyme activities reflected decreased protein levels. mRNAs for tyrosinase, tyrosinase-related protein 1, dopachrome tautomerase, silver protein and melanocortin 1 receptor also decreased after H(2)O(2) treatment, and recovered at different rates. Downregulation of melanocyte differentiation markers mRNAs was preceded by a decrease in microphthalmia transcription factor (Mitf) gene expression, which was quantitatively similar to the decrease achieved using 12-O-tetradecanoylphorbol-13-acetate. Recovery of basal Mitf mRNA levels was also observed clearly before that of tyrosinase. Therefore, oxidative stress may lead to hypopigmentation by mechanisms that include a microphthalmia-dependent downregulation of the melanogenic enzymes.
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PMID:Inhibition of melanogenesis in response to oxidative stress: transient downregulation of melanocyte differentiation markers and possible involvement of microphthalmia transcription factor. 1149 72


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