bluuebunny/crossref_metadata_2025 huggingface dataset:
Melanoma, Growth Factors, and Cutaneous Paraneoplastic Syndromes
Authors: ELLIS DARREL L. , CHOW JIM C. , NANNEY LILLIAN B. , INMAN WENDELYN H. , KING LLOYD E.
Published: July 2006

Paraneoplastic syndromes are systemic reactions in patients with cancers that are unrelated to tumor size or location. Cutaneous paraneoplastic syndromes include proliferative, metabolic, and inflammatory skin disorders. Both systemic and cutaneous paraneoplastic reactions may occur in patients with malignant melanoma. Cancers, including melanoma, may produce growth factors, which may be responsible for proliferative cutaneous paraneoplastic syndromes. A patient with malignant melanoma we previously reported, who had the sudden onset of acanthosis nigricans, skin tags (acrochordons), and seborrheic keratoses provides a model for proliferative cutaneous paraneoplastic syndromes. High levels of α‐TGF were found in the patient's urine prior to melanoma removal. The increased level of α‐TGF declined after the melanoma was removed, and a corresponding clinical improvement in his acanthosis nigricans, skin tags, and seborrheic keratoses occurred. In the skin lesions, EGF receptors were abnormally present throughout all epidermal layers prior to melanoma removal, and returned to their normal distribution in the basal layers after surgery. Ectopic growth factor production by malignant melanomas and other epithelial neoplasms may cause rare, but distinctive cutaneous paraneoplastic lesions. The model of melanoma, cutaneous paraneoplastic syndromes, and growth factors may provide understanding of both cutaneous lesions associated with neoplasia, and benign cutaneous lesions.
Phenotypic Variation and Systemic Cancer in the FAMMM Syndrome
Authors: FUSARO RAMON M. , LYNCH HENRY T. , LYNCH JANE F. , MADSEN NANCY J.
Published: July 2006

Familial atypical multiple mole melanoma (FAMMM) syndrome, a cancer‐associated genodermatosis, is a dominantly inherited heterogeneous disorder with variable expressivity of both its cutaneous and cancer phenotypes. By using a verified historical review technique of cancer documentation (idout patient health records, pathology reports/slides, autopsy reports/slides, and death certificates) of all anatomic sites in all members of a modified nuclear pedigree (first‐degree relatives plus maternal and paternal grandparents, aunts, and uncles) over several generations, we showed that the FAMMM syndrome is similar to the majority of autosomal dominant inherited cancer‐associated genodermatoses and has excessive risk for cancer of multiple anatomic sites. With respect to the FAMMM syndrome, these cancers involved the breast, respiratory tract, gastrointestinal system, the eye (intraocular melanoma), and the lymphatic system. These FAMMM pedigrees showed some of the following distinctive characteristics of hereditary cancer: 1) integral patterns of cancer within and between pedigrees; 2) early age of onset of cancer; 3) prolonged survival of some pedigree members with cancer; and 4) an excess of multiple primary melanomas and cancers of variable anatomic sites. The presence of these features indicates that these cancers of variable anatomic sites may be etiologically associated with the FAMMM syndrome. Heterogeneity should be investigated in FAMMM pedigrees with attention to consistent differences in size and distribution of atypical lesions, age at cancer onset, and pattern of tumor occurrences. The occurrence of FAMMM pedigrees in the general population or among pedigrees of probands with atypical nevi is not known. The occurrence of systemic cancers in these FAMMM pedigrees requires the development of cancer surveillance programs that are specifically modified to the particular cancer pattern of each pedigree.
New Variants of B16 Mouse Melanoma: Differentiation and Metastatic Properties
Authors: AUBERT CHRISTIAN , VOULOT CHRISTIAN , ROUGE FRANÇOISE , PIRISI VICTOR , GALINDO JEAN‐REMY
Published: July 2006

A system of tumor transplantation has been developed to select metastatic variants of B16 in mutants of the C57BL/6J black strain of mice. The effects of transplantation into nonagouti a/a and mutant recipients on the production of melanin and on the metastatic potential of tumors were investigated. Transplantation of the pigmented B16 melanoma from a nonagouti black a/a host to a yellow mutant Ay/a recipient resulted in an achromic and metastatic variant melanoma, designated YB16. The amelanotic phenotype occurred consistently after more than ten passages through yellow mice and simultaneously with an increase in the incidence of pulmonary metastases. When YB16 was transplanted back to the nonagouti black a/a host, a second variant, MB 16, characterized by its variable pigmentation, was obtained. Pigmented and/or entirely achromic tumors were observed. MB16 was dramatically more metastatic than B16 and YB16 when injected s.c. or i.v. Metastases in the lungs were pigmented and/or achromic. The properties of tumor cells derived from artificially induced metastases were investigated after s.c. and i.v. injections. Whereas the metastatic cells expressed a potent ability to generate metastases when injected s.c., no differences in the incidence of metastases, as compared to the metastatic potential of cells of parental origin, were observed after i.v. injection. In the MB16 variant, there appeared to be an inverse relationship between differentiation (production of melanins) and malignancy. Our results demonstrate that differentiation and metastatic behaviour are dependent on specific mutations in the host environment which generate a pool of tumor cells from which highly metastatic variants can be selected.
Specificity of Growth Inhibition of Melanoma by 4‐Hydroxyanisole
Authors: KULKARNI GAJANAN A. , NATHANSON LARRY
Published: July 2006

An experimental study using human melanoma (NEL‐M1), rat hepatoma (Fu5‐5), and human kidney (293‐31) cell lines was undertaken in order to evaluate the antitumor activity of 4‐hydroxyanisole (4‐OHA) in vitro. Prior reports have indicated highly specific antitumor activity of 4‐OHA against melanoma cells in vitro. This specific antitumor activity has been proposed to be due to the oxidation of 4‐OHA by tyrosinase to cytotoxic oxidation products.

Dose‐dependent cytotoxicity was observed when cells were cultured for 72 h in the presence of 4‐OHA. At 100 μM, 4‐OHA produced growth inhibition of 62%, 32%, and 55% in melanoma, hepatoma, and kidney cell lines, respectively. No effect was seen at 10 μM 4‐OHA. 1,000 μM 4‐OHA produced 100% kill. Tyrosinase activity was detected only in melanoma cells.

The effect of 100 μM 4‐OHA on the incorporation of 3H DNA precursors in melanoma, hepatoma, and kidney cells was also studied. Thymidine incorporation was inhibited in all three cell lines at the lowest cell density tested, with the greatest inhibition seen on melanoma cells. As cell density increased, the effect of 4‐OHA on thymidine incorporation decreased. With respect to RNA synthesis, 4‐OHA significantly reduced the incorporation of uridine in all three cell lines, with the greatest effect in melanoma cells. Cell density also affected the inhibition of uridine incorporation, but to a lesser extent than that observed on thymidine incorporation. The effect of 4‐OHA on leucine incorporation was modest and uninfluenced by cell density.

Thus, cytotoxicity of 4‐OHA may involve two different mechanisms. The first, predominating in melanoma cells, is mediated by tyrosinase, which converts 4‐OHA into cytotoxic products. The second (non melanoma cells) is independent of tyrosinase and involves inhibition of both RNA and DNA synthesis.
Gene Transfer and Expression Studies in Cultured Avian Neural Crest Cells Differentiating Into Melanocytes
Authors: VIELKIND JUERGEN R. , VOGEL KRISTTNE S.
Published: July 2006

Neural crest cells obtained from explanted neural tubes take up, express, and retain exogenous DNA applied by the CaPO4 co‐precipitation method during their differentiation into melanocytes. High efficiencies of gene transfer were obtained with both supercoiled DNA and intact phage particles; linear DNA or DNA from the phage yielded very low efficiencies. There is some evidence that transferred gene expression is differentiation dependent. The system should be useful for studies concerned with the analysis of cell developmental genes and their regulatory elements.
Optimization of Conditions for Preparing Synthetic Pheomelanin
Authors: ITO SHOSUKE
Published: July 2006

Synthetic melanins are often used as the standards for natural melanins. Conditions for preparing synthetic pheomelanin from L‐dopa and L‐cysteine were studied under different temperatures (25 and 37deg;C), different amounts of cysteine (1.5 and 2.0 eq), and different amounts of tyrosinase (10 and 20 mg). Effects of addition of catalase and of replacement of oxygen with air were also examined. The best preparation of pheomelanin was obtained in a good yield, when 1 mmol of L‐dopa was oxidized at 25deg;C under oxygen current in 100 ml of a pH 6.8 buffer by 20 mg of mushroom tyrosinase inn the presence of 1.5 mmol of L‐cysteine. The pheomelanin thus obtained had an elemental composition and an absorption spectra that were very similar to those from a pheomelanin prepared by tyrosinase oxidation of 5‐S‐cysteinyldopa. Hydrolysis of synthetic pheomelanins and pheomelanic tissues with hydriodic acid gave aminohydroxyphenylalanines (AHP) as a major product and hydroxybenzothiazolylalanines as a minor product. It is proposed that AHP can be used as a specific indicator of purity of pheomelanins.
Present Status of the Medical Irradiation Facility at the Musashi Reactor
Authors: MATSUMOTO TETSUO , AIZAWA OTOHIKO , NOZAKI TETSUYA , SATO TADASHI
Published: July 2006

Boron neutron capture therapy (BNCT) of malignant brain tumors has been efficiently performed since March 1977, and the first human case of malignant melanoma was also successfully treated on July 1987 in our reactor (Musashi reactor, TRIGA‐II, 100 kW).

To obtain both good irradiation field characteristics and a better irradiation facility, some tests and developments have been continued in accordance with the study of medical and biological irradiations. The results of these evaluations and a new approach are presented.
Specific Kilting of Human Melanoma Cells With an Efficient 10B‐Compound on Monoclonal Antibodies
Authors: KOMURA ATSUKO , TOKUHISA TAKESHI , NAKAGAWA TOSHIO , SASASE AKIHIRO , ICHIHASHI MASAMITSU , FERRONE SOLDANO , MISHIMA YUTAKA
Published: July 2006

We previously established methods which have enabled us to target a sufficient number of 10B atoms on human melanoma cells to destroy them by thermal neutron irradiation. Monoclonal antibodies were here used as vector of 10B atoms on the target cell. Thermal neutrons require at least 10910B atoms to destroy the cell. In order to accumulate an adequate number of 10B atoms on target cells, our first approach was to make an effective compound that contains 12 atoms of 10B in a molecule. The second step was to conjugate the compound with an avidin molecule (10B12‐avidin). One molecule of the 10B12‐avidin carries about 30 atoms of 10B. This 10B12‐avidin can be specifically targeted on human melanoma cells by biotinated monoclonal antibodies specific for the cells. Furthermore, the number of 10B atoms on target cells can be augmented by a hapten‐antihapten monoclonal antibody system. The cultured human melanoma cells treated with these methods were damaged by thermal neutron irradiation. This is the first study that indicates thermal neutrons do injure target cells boronated by monoclonal antibodies.
Preclinical and Phase I Studies of Monoclonal Antibodies in Melanoma: Application to Boron Neutron Capture Therapy of Melanoma
Authors: HERSEY PETER
Published: July 2006

Monoclonal antibodies (MAbs) provide an attractive method of selectively localizing sufficient boron atoms around tumour cells to capture neutrons. Assuming that 108‐101010B atoms are needed for one capture event and that 103‐104 atoms can be coupled to each antibody molecule, then 105‐106 antibody molecules gathered on an individual cell will destroy that cell. Binding to normal tissues, on the other hand, would need to be at least 20‐fold less than that to tumour tissues to avoid toxic effects of neutrons on surrounding tissues. Preclinical studies in animals show that several MAbs may bind to melanoma cells in sufficient quantities in vitro to localize the required amount of Boron per cell. Whether this will occur in vivo, however, may depend not only on antigen density but a variety of other properties of the tumour cells and MAbs. These include the Ig class and affinity of the antibody and whether the antibody is internalized into the tumour cell. The ratio of uptake between tumour and normal tissue is governed by such factors as the percentage of tumour cells within a tumour expressing the antigen and whether the MAb react with normal tissues. Use of Fab or F(ab)2 preparations of the MAb may increase the uptake ratio by preventing uptake of MAb by cells with Fc receptors. In contrast to preclinical animal studies, tumour/normal tissue uptake ratios in phase I studies in humans have been disappointingly low. This appears to be mainly due to the high nonspecific uptake of MAbs in human tissues but may also result from the lower relative blood supply through small tumours in humans compared to transplants in mice. Factors that may increase the uptake ratios include use of an irrelevant MAb to block nonspecific uptake, injection of higher amounts of labelled specific MAbs, and local rather than systemic administration of the MAb.
Optimization of Boron and Neutron Delivery for Neutron Capture Therapy
Authors: FAIRCHILD R.G. , SLATKIN D.N. , CODERRE J.A. , MICCA P.L. , LASTER B.H. , KAHL S.B. , SOM P. , FAND I. , WHEELER F.
Published: July 2006

A number of groups in the United States have received funding that will permit evaluation of the clinical efficacy of the neutron capture therapy (NCT) procedure. Various reactors are being modified to allow the construction of an epithermal neutron beam.

At the Brookhaven Medical Research Reactor (BMRR), the patient irradiation facility is being modified to produce an optimized epithermal neutron beam. An 80‐cm‐thick Al‐D2O mixture (184 g/cm2, 25% D2O by volume) is being installed in the shutter assembly. One‐dimensional calculations indicate that this configuration should provide an epithermal neutron flux density of ∼1 × 109 n/cm2/sec at 3 MW and a concomitant fast neutron dose rate of ∼2 × 10−11 rad per epithermal neutron (assuming a homogeneous Al‐D2O mixture). The actual geometry will be an inhomogeneous array of D2O and Al layers producing parameters somewhat less favorable than those listed above; experimental verification is in progress.

Significant gains have recently been made in selectively targeting B to melanoma with various melanaffinic compounds, including p‐boronophenylalanine, and with boronated porphyrins that may be applicable to a variety of tumors. Neutron capture radiographs have been obtained with the above compounds, and efforts have been made to quantitate boron uptake in growing and quiescent or necrotic regions of tumor via double‐labeling techniques obtained with tritiated thymidine. A correlation between therapeutic efficacy and the ability to deliver boron to viable areas of tumor has been observed.
Induction of DNA Double‐Strand Breaks by 157Gd Neutron Capture
Authors: MARTIN ROGER F. , D'CUNHA GLENN , PARDEE MARSHALL , ALLEN BARRY J.
Published: July 2006

The rationale of boron (10B) neutron capture therapy (BNCT) is based on the high thermal neutron capture cross section of 10B and the limited maximum range (about one cell diameter) of the high LET fission products of the boron neutron capture (NC) reaction. The resulting radiochemical damage is confined to the cell containing the BNC reaction. Although other nuclides have higher thermal neutron capture cross sections than 10B, NC by such nuclides results in the emission of highly penetrating gamma rays. However, gadolinium‐157 (157Gd) n‐gamma reaction is also accompanied by some internal conversion and, by implication, Auger electron emission. Irradiation of Gd3+‐DNA complexes with thermal neutrons results in the induction of DNA double‐strand (ds) breaks, but the effect is largely abrogated in the presence of EDTA. Thus, by analogy with the effects of decay of Auger electron‐emitting isotopes such as 125I, the Gd NC event must take place in the close proximity of DNA in order to induce a DNA ds break. It is proposed that 157Gd‐DNA ligands therefore have potential in NCT. The thermal neutron capture cross section of 157Gd, a nonradioactive isotope, is more than 50 times that of 10B.
Sublethal and Potentially Lethal Damage Repair on Thermal Neutron Capture Therapy
Authors: UTSUMI HIROSHI , ICHIHASHI MASAMITSU , KOBAYASHI TOORU , ELKIND MORTIMER M.
Published: July 2006

Tonicity shock or caffeine postirradiation treatment makes evident fast‐type potentially lethal damage (PLD). Caffeine expresses fast‐type PLD more efficiently than tonicity shock in X‐irradiated B‐16 mouse melanoma cells, compared with V79 Chinese hamster cells. The survival curves of thermal neutrons for either V79 or B‐16 cells exhibit no shoulder. Neither V79 nor B‐16 cells show the sublethal damage (SLD) repair of thermal neutrons. Caffeine‐sensitive fast‐type PLD repairs exist in X‐irradiated B‐16 cells, as well as V79 cells. The fast‐type PLD repair of B‐16 cells exposed to thermal neutrons alone is rather less than that of X‐irradiated cells. Furthermore, an extremely low level of fast‐type PLD repair of B‐16 cells with 10B1‐paraboronophenylalanine (BPA) preincubation (20 hours) followed by thermal neutron irradiation indicated that 10B(n,α)7Li reaction effectively eradicates actively growing melanoma cells. The plateau‐phase B‐16 cells are well able to repair the slow‐type PLD of X‐rays. However, cells can not repair the slow‐type PLD induced by thermal neutron irradiation with or without 10B1‐BPA preincubation. These results suggest that thermal neutron capture therapy can effectively kill radioresistant melanoma cells in both proliferating and quiescent phases.
Phosphorylation of the Carotenoid Droplet Protein p57 by the Catalytic Subunit of Cyclic Adenosine Monophosphate‐Dependent Protein Kinase and the Effect of Fluoride
Authors: YANG CHANG‐FENG , ZENG ZHAO‐CHUNG , CHOU SHUI‐CHOU , YU FU‐XIN , TAYLOR JOHN D. , TCHEN T.T.
Published: July 2006

We have previously shown that the dispersion and aggregation of carotenoid droplets in goldfish xanthophores are regulated, respectively, by phosphorylation and dephosphor‐ylation of a carotenoid droplet protein p57. There is a basal level of p57 phosphorylation of p57 in unstimulated cells, which is greatly stimulated by adrenocorticotropic hormone (ACTH) or cyclic adenosine monophosphate (cAMP) acting via cAMP‐dependent protein kinase. We have also observed that, in permeabilized xanthophores, pigment dispersion can be induced when cAMP is replaced by fluoride. Since p57 has multiple phosphorylation sites, there is the question of whether all p57 phosphorylation is by cAMP‐dependent protein kinase or whether phosphorylation by cAMP‐independent protein kinase coupled with inhibition of phosphatase activity by fluoride can replace cAMP‐dependent phosphorylation. We show here that all p57 phosphorylation is by cAMP‐dependent protein kinase and that the ability of fluoride to replace cAMP for pigment dispersion in permeabilized cells is probably due to activation of adenylcyclase. We also show that ACTH causes an approximately threefold increase in the level of cAMP in these cells.
Neural Control of Motile Activity of Light‐Sensitive Iridophores in the Neon Tetra
Authors: NAGAISHI HIROSHI , OSHIMA NORIKO
Published: July 2006

Experiments with skin pieces revealed that the sympathetic nervous system controls the activity of the light‐sensitive iridophores in the stripes of the neon tetra. The spectral peak reflected from the cells was shifted toward longer wavelengths as a result of a direct interaction between norepinephrine and alpha‐adrenoceptors present on the cell membrane. Adenosine accelerated the recovery from the effects of the amine. Such regulation seems to operate when fish are in an excited state or under stress. Since alpha‐melanophore‐stimulating hormone (alpha‐MSH), melanin‐concentrating hormone (MCH) and melatonin caused the responses only at high concentrations, it is possible that these peptides and amine do not affect the properties of the light‐reflecting cells in vivo.
Absence of Murine Melanoma 5′‐Nucleotidase Activity Is Not Attributable to a Detectable Inhibitor
Authors: MOODY DANA , BIJWAARD KAREN E. , GERSTEN DOUGLAS M.
Published: July 2006

Previous observations indicated the absence of demonstrable 5′‐nucleotidase activity in six of seven cultured murine melanoma cell lines. It could not be determined from those studies whether the enzyme was absent, or whether an inhibitor was present. The current studies indicate that no inhibitor can be demonstrated, therefore the enzyme is absent.
Ionic Requirements for Catecholamine Aggregating Actions on the Teleost Poecilia reticulata Melanophores
Authors: VISCONTI MARIA APARECIDA , CASTRUCCI ANA MARIA DE LAURO
Published: July 2006

Norepinephrine (NE) and phenylephrine (Phe) were employed to study the ionic requirements for alpha adrenoceptor activation in the teleost Poecilia reticulata melanophores.

As expected the beta adrenoceptor blocker, propranolol, increased the sensitivity of the preparation to NE (5.8 times), and was therefore employed in all the experimental procedures. Neither cocaine (a neuronal uptake blocker) nor dexamethasone (an extraneuronal uptake blocker) enhanced the sensitivity of the preparation to NE, suggesting that these inactivating mechanisms would not play a role in P. reticulata pigmentary system. However, in the absence of calcium, the dose‐response curve (DRC) to NE was displaced to the left about 3.5 times, whereas the DRC to Phe was not affected. These results indicate that a neuronal uptake is active, but was not demonstrated by the classical pharmacological tools, probably due to an assymmetric display of the nervous endings.

The DRC to NE was rightward displaced (14.1 times) in the presence of the calcium channel blocker Verapamil, whereas the DRC to Phe was not affected. These data suggest that P. reticulata melanophores possess a mixed population of alpha1 and alpha2 adrenoceptors, the activation of the latter eliciting an extracellular calcium influx.

In sodium‐free saline, the DRC to NE was rightward shifted (6.6 times) and the response to Phe was impaired in such a way that the maximal response was not achieved. The DRC to both NE and Phe were rightward displaced (7.9 and 2.7 times respectively) in the presence of the sodium channel blocker tetrodotoxin (TTX) 10−7M.

In potassium‐free saline, the melanophore sensitivity to Phe was increased, whereas the responses to NE were not affected, suggesting a differential sensitivity of the two alpha adrenoceptor subtypes to the resulting membrane hyperpolarization.

Based on the literature and on our data we propose that P. reticulata melanophores possess a mixed population of alpha1 and alpha2 receptors. The activation of both subtypes of alpha adrenoceptors elicits a Na+ ion influx through TTX‐sensitive sodium channels. The stimulation of alpha2 adrenoceptors also requires an extracellular calcium influx, through the opening of slow calcium channels.
Isolation of Tyrosinase From Bovine Eyes
Authors: WITTBJER ANNA , ODH GERD , ROSENGREN ANNA‐MARIA , ROSENGREN EVALD , RORSMAN HANS
Published: July 2006

Pigmented tissues from bovine eye were used as a source for isolation of tyrosinase from normal melanocytes. Tyrosinase is highly hydrophobic and the isolation procedure is mainly based on the use of hydrophobic interaction chromatography. The bovine enzyme is, in contrast to the human melanoma tyrosinase, mainly soluble. The predominant part of the ocular enzyme from cow has a molecular weight and isoelectric behavior similar to that of the soluble tyrosinase in the human melanoma cells. The N‐terminal amino acid sequence of isolated bovine tyrosinase was determined by automated Edman degradation. The N‐terminal amino acid sequence from normal bovine tyrosinase was identical to the sequence of an N‐terminal region of mouse melanoma tyrosinase predicted from a c‐DNA clone by Kwon et al. (1988). The amino acid sequence of bovine tyrosinase shows homology to that of human tyrosinase (Wittbjer et al., 1989), but three amino acids of the 16 residues determined by us differed. Histidine was the N‐terminal amino acid.
Pigment Types in Selected Color Genotypes of Asiatic Sheep
Authors: ALIEV GULYAM , RACHKOVSKY MICHAEL , ITO SHOSUKE , WAKAMATSU KAZUMASA , IVANOV ALEXANDR
Published: July 2006

The types and amounts of pigments in fibers from variously colored Tajik, Hissar, and Caracul sheep were determined by three methods: high‐performance liquid chromatography, electron spin resonance spectroscopy, and light microscopic evaluation of mel‐anosomes. In both dominant and recessive black lambs the color is due to eumelanin pigment. Brown and red phenotypes are the result of interaction of Awt and EBI, EBr, or EY alleles, and these colors are caused by mixtures of eumelanin and pheomelanin in varying ratios. The HPLC and ESR measurements detected these differences in melanin type, while direct characterization of melanosomes generally failed to distinguish between melanin type or relative ratio of melanin type.
Psoralens Stimulate Mouse Melanocyte and Melanoma Tyrosinase Activity in the Absence of Ultraviolet Light
Authors: MARWAN MOHAMED M. , JIANG JINWEN , CASTRUCCI ANA MARIA DE LAURO , HADLEY MAC E.
Published: July 2006

Psoralens (8‐methoxypsoralen, 5‐methoxypsoralen and 4,5,8‐trimethylpsoralen) stimulate mouse melanoma cell (S91 and B16/F10) tyrosinase activity in vitro in a dose‐related manner. Stimulation of enzyme activity by the psoralens was evoked in the presence or absence of light. In the presence of a melanotropin the actions of the psoralens were generally at least additive compared to the individual actions of the two agonists. The actions of the psoralens were acute and depended upon the constant presence of the agents to maintain enhanced melanoma tyrosinase activity. Tyrosinase activation by the psoralens, like that of α‐melanotropin, was blocked by actinomycin‐D or cycloheximide demonstrating that the actions of the drugs may have involved both transcriptional and translational events in the stimulation of melanogenesis. Psoralens also stimulated an immediate darkening of frog skins in vitro. Topically applied psoralens were transdermally delivered to the systemic circulation resulting in a conversion from pheomelanogenesis to eumelanogenesis within follicular melanocytes throughout the entire skin of mice (C57BL/ 6JAy maintained in the dark. Taken together, these results demonstrate that psoralens activate processes within melanocytes resulting in both an immediate translocation of melanosomes within the cell (frog) or in a slower genomic event involving tyrosinase activation (melanoma cells) and eumelanin formation (mouse follicular melanocytes).
In Vitro Phenotypic Alteration of Human Melanoma Cells Induced by Differentiating Agents: Heterogeneous Effects on Cellular Growth and Morphology, Enzymatic Activity, and Antigenic Expression
Authors: TAKAHASHI HIROYUKI , PARSONS PETER G.
Published: July 2006

Sodium butyrate (butyrate), 5‐azacytidine (5Aza‐C), dimethyl sulfoxide (DMSO), and dimethyl formamide (DMF) were applied to a human melanoma cell line for the purpose of inducing pigmentation and terminal differentiation. The results are summarized as follows: 1) butyrate, DMSO, and DMF had a strong cytostatic effect, arresting cells in the G1 phase of the cycle; 2) butyrate caused a morphological change to spindle shape whereas DMSO and DMF produced rounded cells, without affecting the levels of vimentin and intermediate filaments; 3) tyrosinase activity and melanization were stimulated by DMSO and DMF but not by butyrate; 4) butyrate induced several membrane‐bound enzyme activities (alkaline phosphatase and ‐γ‐glutamyl transpeptidase); 5) changes in the expression of antigens related to tyrosinase activity (2B7 and 5C12) only partly corresponded to the changes in enzyme activity; 6) expression of the melanosomal B863 antigen was decreased by butyrate, DMSO, and DMF; and 7) the action of DMF resembled that of DMSO whereas 5Aza‐C had little effect. The results indicate that these differentiating agents activate different sets of genes, the melanogenic pathway being activated independently of ‐γ‐glutamyltranspeptidase. The down regulation of B8G3 antigen by these agents may provide a common focus for understanding the essential action of differentiation inducers in melanoma cells.
Tyrosinase Activity (TH, DO, PAGE‐Defined Isozymes) and Melanin Production in Regenerating Hairbulb Melanocytes of Lethal Yellow (Ay/a), Black (a/a), Agouti (AwJ/AwJ) and Albino (a/a/c2J/c2J) Mice (C57BL/6J)
Authors: GRANHOLM NELS H. , OPBROEK ADAM J. , HARVISON GREGG A. , KAPPENMAN KARL E.
Published: July 2006

We compared tyrosinase activity (TH, DO, and native PAGE‐defined isozymes) and melanin production in participate and soluble fractions of hairbulb melanocytes of lethal yellow (Ay/a C/C), nonagouti black (a/a C/C), and albino (a/a c2J/c2J) of 3‐, 6‐, 9‐, and 12‐day regenerating hairbulbs. With respect to tyrosine hydroxylase (TH) and dopa oxidase (DO) activities, Ay/a melanocytes possessed only 25‐35% of the activity of a/a; there were no genotype differences in either the subcellular distribution of activity in soluble and particulate fractions or in the relative increases of activity over the 12‐day developmental period. TH data on wild‐type agouti (AwJ/AwJ) mice over the 3‐11 day regeneration interval showed an activity intermediate between that of a/a and Ay/a; the rate of TH increase reflected black and yellow phases of the agouti hair cycle. Analyses of the number and densities of dopa‐sensitive bands following native PAGE of 3‐, 6‐, 9‐, and 12‐day hairbulb fractions of a/a and Ay/a mice suggested stage‐dependent patterns. A comparison of rates and amounts of melanin production in 3‐, 6‐, 9‐, and 12‐day fractions showed consistent melanin production in Ay/a to be 10‐20% that of a/a; however, fold increases in melanin production over the four stages were similar between genotypes. Overall, tyrosinase activity data support the notion that agouti locus modification of tyrosinase activity is a graded or quantitative rather than a qualitative phenomenon.
Experimental Boron Neutron Capture Therapy for Melanoma: Systemic Delivery of Boron to Melanotic and Amelanotic Melanoma
Authors: CODERRE JEFFREY A. , GLASS JOHN D. , PACKER SAMUEL , MICCA PEGGY , GREENBERG DENNIS
Published: July 2006

The boron‐containing melanin precursor analogue p‐boronophenylalanine (BPA) has previously been shown to selectively deliver boron to pigmented murine melanomas when administered in a single intragastric dose. If boron neutron capture therapy is to become a clinically useful method of radiation therapy for human malignant melanoma, the boron carrier must be capable of delivering useful amounts of boron to remote tumor sites (metastases) and to poorly pigmented melanomas. We have now determined the ability of BPA to accumulate in several nonpigmented melanoma models including human melanoma xenografts in nude mice. The absolute amount of boron in the nonpigmented melanomas was about 50% of that observed in the pigmented counterparts but was still selectively concentrated in the tumor relative to normal tissues in amounts sufficient for effective neutron capture therapy. Single intragastric doses of BPA resulted in selective localization of boron in the amelanotic Greene melanoma carried in the anterior chamber of the rabbit eye and in a pigmented murine melanoma growing in the lungs. The ratio of the boron concentration in these tumors to the boron concentration in the immediately adjacent normal tissue was in the range of 3:1 to 4:1. These distribution studies support the proposal that boron neutron capture therapy may be useful as a regional therapy for malignant melanoma.
Iris Stromal Pigment Cells of the Ringed Turtle Dove
Authors: TILLOTSON HOLLY M. , OLIPHANT LYNN W.
Published: July 2006

Irides from adult Ringed Turtle Doves (Streptopelia risoria) were examined using both light and electron miscroscopy. The anterior surface of the iris stroma contained numerous large venous sinuses overlying bright yellow pigment cells which we classified as “reflecting xanthophores.” The pigment cells were filled with irregularly arranged yellow reflecting crystals and occasional pterinosome‐like structures. The irides were extracted in NaOH and the extracted pigments analyzed using paper chromatography and spectro‐photometry. A unique bright orange fluorescent band was found in the iris extract, but the chemical nature of the band was not determined. Although guanine was expected to be a major component of the reflecting "platelets," based on previous work with other Columbiformes, it could not be demonstrated chromatographically or spectrophotometrically.
Ultrastructure of Melanocytes in Chronically Sun‐Exposed Skin of Elderly Subjects
Authors: BREATHNACH A.S. , NAZZARO‐PORRO M. , PASSI S. , PICARDO M.
Published: July 2006

Chronically sun‐exposed facial skin of three females aged 68, 71, and 78 years, and of a male aged 78, was examined by electron microscopy in order to study the condition of the epidermal melanocytes. Considerable heterogeneity of morphological and functional characteristics of the cells was observed. The majority of melanocytes were large, active, with occasionally tabulated or double nuclei, an appearance indicative of hyperstimulation. Some cells exhibited an appearance of having reached the end of an active life cycle and were labelled “aged.” Others, in the upper end of the outer root sheath of hair follicles and adjacent interfollicular epidermis, presented a typically inactive appearance, indistinguishable from that of fetal melanocytes, or of those in unexposed skin of younger subjects. A cell with indented nucleus, fully melanised melanosomes, and hypertrophie Golgi apparatus was sporadically seen. Minute foci of dissociation of keratocytes were present, and melanocytes included in these were frequently disrupted. Swelling of mitochondria and cytoplasmic lipid droplets occurred sporadically within all the above variants of melanocytes. It proved difficult to establish criteria of specific sun damage of melanocytes. It is suggested that either the melanocytes exhibiting stimulation or the relatively inactive ones could be the precursors of the proliferating cells of lentigo maligna.
New Mechanism of Melanosomes Transport into Hair of Lambs of Different Breeds and Genotypes
Authors: RACHKOVSKY MICHAEL L.
Published: July 2006

By light microscopic investigation of skin and wool specimens of newborn lambs, we discovered a previously unknown mechanism for melanosomes transport in the process of dermal papilla melanocytes regular mitosis and migration into the hair shaft. This mechanism plays a great role in hair pigmentation especially in dominant (ED/ED) and recessive (Aa/Aa) black lambs of all investigated breeds. The rate of pigment cell mitosis, proliferation, and migration differs greatly in lambs of investigated color genotypes. In black genotypes the rate of melanocyte mitosis is very high and is approximately the same as in the hair bulb matrix cells, whereas in brown and red genotypes this rate is much lower. Melanocyte mitosis in the light red and tan groups was not found.
Differentiation of Extracutaneous Melanocytes in Embryos of the Turtle, Trionyx sinensis japonicus
Authors: HOU LING , TAKEUCHI TAKUJI
Published: July 2006

The present study investigates the mode of differentiation of neural crest‐derived melanocytes in the embryos of the soft‐shell turtle, Trionyx sinensis japonicus. DOPA reaction‐positive melanoblasts were first detected in 10‐day‐old embryos. Melanocyte differentiation in terms of pigmentation takes place from the day 16 of development. Melanin pigments were found in the dorsal integument as well as in various extracutaneous tissues such as skeletal muscle, dorsal aorta, peritoneum, blood vessels, choroid, lung, bone marrow, fat tissues and in the connective tissue of the nose. These results suggest the presence of a specific environmental regulation of the melanoblast differentiation in the soft‐shell turtle.
Peroxidase and Tyrosinase Are Present in Secondary Lysosomes That Degrade Photosensory Membranes of the Crayfish Photoreceptor: Possible Role in Pigment Granule Formation
Authors: SCHRAERMEYER ULRICH , STIEVE HENNIG
Published: July 2006

Three enzymes (acid phosphatase, peroxidase, and tyrosinase) were localized by electron microscopy within the retina of crayfish Orconectes limosus. Peroxidase activity was observed only in lamellar bodies, which are secondary lysosomes and degrade photosensory membrane. After H2O2 was omitted from the reaction medium, peroxidase activity in lamellar bodies was partly inhibited but was not missing completely. After addition of sodium pyruvate, which inhibits endogenous generation of H2O2, staining of lamellar bodies was absent. Tyrosinase activity was found in lamellar bodies and in small vesicles within the rhabdoms similar to those found positive for acid phosphatase. Granules (500–700 nm in diameter) with an electron opaque matrix and mature screening pigment granules showed tyrosinase activity. Moreover, lamellar structures within membrane‐bound organelles that additionally contained screening pigment‐like granules were electron dense because of tyrosinase activity. After addition of phenylthiourea (PTU) to the incubation medium, lamellar bodies did not generally contain electron dense deposits, although weak staining of single membranes still was sometimes observed. After addition of sodium pyruvate in combination with PTU, no staining was detected. The possible role of tyrosinase in ommochrome synthesis within secondary lysosomes that degrade photosensory membrane is discussed.
Inhibition of Tumor Cell Invasion by Verapamil
Authors: YOHEM KARIN H. , CLOTHIER JOHN L. , MONTAGUE SANDRA L. , GEARY ROSEMARY J. , WINTERS ADRIAN L. , HENDRIX MARY J.C. , WELCH DANNY R.
Published: July 2006

Verapamil, a calcium channel antagonist, inhibits murine B16 melanoma and colon adenocarcinoma C26 tumor metastasis by altering platelet aggregation [Tsuruo, T., et al. (1985) Cancer Chemother. Pharmacol., 14:30–33]. However, the role of calcium homeostasis in regulating several biochemical pathways implicated in other steps of the meta‐static cascade suggests that calcium channel antagonists could also inhibit metastasis by other mechanisms. In this report, non‐toxic doses of verapamil reversibly decreased human A375M and C8161 melanoma cell invasion and metastasis in a dose‐dependent manner. Verapamil reduced cellular invasion and metastases by up to 96% (range 78–96%). Concomitantly, verapamil disrupts microtubule and microfilament organization and inhibits unidirectional cell migration but does not affect cellular adhesion to endothelial mono‐layers or reconstituted basement membranes. In addition, tumor cells treated with verapamil have a decrease in mRNA of type IV collagenase, a proteinase important in tumor cell degradation of basement membranes. Collectively, these data offer additional evidence regarding the mechanisms of action of verapamil as an anti‐metastatic agent.
Does the Introduction of a New Player, the Endoplasmic Reticulum, Create More or Less Confusion in Understanding the Mechanism(s) of Pigmentary Organelle Translocations?
Authors: TAYLOR JOHN D.
Published: July 2006

In 1925, Wilson listed, in his classic third edition of Cell in Development and Heredity, four theories for the morphological and physiological characteristics of cytoplasm; each theory provided some sort of explanation as to the mechanism(s) of organelle translocations. During the past twenty years, cell biologists have focused their attentions on the cell's cytoskeleton, microtrabecular lattice, and associated mechanochemical motors which drive organelles along cytoskeletal tracks. A number of cell types have been used to study organelle translocations, but chromatophores, pigment cells, from cold‐blooded vertebrates have been one of the more popular models. This article reviews some of the research findings during the past twenty years, particularly those involving cytoplasmic elements: i.e, microfilaments, intermediate filaments, microtubules, and mechanochemical motors. In addition, it contrasts the proposed involvement of these elements in organelle translocations with the endoplasmic reticulum, a tubulovesicular organelle, which we recently demonstrated is responsible, through its elongation or retraction, for the translocations of carotenoid droplets in goldfish xanthophores and swordtail fish erythrophores. Here, the carotenoid droplets are not free in the cytoplasm and do not translocate via cytoskeletal tracks, but instead are attached to or are a part of the endoplasmic reticulum. On the other hand, carotenoid droplets of squirrel fish erythrophores are free in the cytoplasm and appear to translocate via microtubules. Finally, the rates of pigmentary organelle translocations are reviewed in light of the participation of the cytoskeletal elements with the endoplasmic reticulum.
B700 Antigen as a Component of an Antimelanoma Vaccine: Formalinized Extracellular Antigens
Authors: SHRAYER DAVID , GERSTEN DOUGLAS M. , KONESS JAMES , MAIZEL ABBY , WANEBO HAROLD , HEARING VINCENT J.
Published: July 2006

Formalin fixation has enjoyed widespread use in the preparation of antibacterial and other vaccines, but rather less use in antitumor vaccines. Previous studies from our laboratories have demonstrated the efficacy of antimelanoma vaccines in mice, produced from formalinized antigens shed by cultured melanoma cells. In this study, we provide evidence that the immunodominant component of that vaccine is the well‐characterized B700 melanoma antigen.
Melanin Standard Method: Empirical Formula
Authors: CHEDEKEL M.R. , MURR B.L. , ZEISE L.
Published: July 2006

Melanin isolated from the ink sac of cuttle fish (Sepia melanin) is a proposed standard for natural eumelanin. Sepia melanin isolated by a standard protocol was submitted for both elemental analysis and quantitative amino acid analysis. The contribution of the detected amino acids to the elemental composition is subtracted from the total elemental analysis, and the resultant elemental composition reflects the composition of the Sepia melanin backbone chromophore. The assumption is made that, for eumelanins, there is only one nitrogen atom per monomeric unit, and thus, the empirical formula for the average monomeric Sepia melanin backbone chromophore was determined. Three key parameters can be determined for any melanin sample; namely, the molar C/N for the average monomeric unit, the formula weight of the average monomeric unit, and the total percent composition of amino acid residues. Three commonly used melanin preparations, namely, natural Sepia melanin, melanin prepared by the in vitro tyrosinase catalyzed polymerization of tyrosine (tyrosine‐enzymatic melanin), and a polymer synthesized by the peroxide oxidative polymerization of tyrosine (tyrosine‐chemical melanin), have been subjected to this standard method of characterization. Tyrosine‐enzymatic and Sepia melanin are quite similar and tyrosine‐chemical melanin is fundamentally different from the other two melanins.
Isolation and Characterization of a Chicken Tyrosinase cDNA
Authors: MOCHII MAKOTO , IIO AKIO , YAMAMOTO HIROAKI , TAKEUCHI TAKUJI , EGUCHI GORO
Published: July 2006

Complementary DNA clones coding for chicken tyrosinase were isolated from retinal pigmented epithelium of chicken embryo. Sequence analysis shows that one of the cDNA clones consisting of 1,997 nucleotides has an open reading frame coding for 529 amino acids. The deduced protein has nine N‐glycosylation sites and a transmembrane region. A sequence comparison of the deduced chicken tyrosinase with the mouse and human homologues revealed that amino acid sequences are conserved for the entire polypeptides. Seventy‐two percent and 73% of amino acids in the chicken sequence are identical to that of the mouse and human tyrosinases, respectively. Histidines neighboring the postulated copper‐binding sites and the cysteines are well conserved. RNA blotting analysis showed that a major transcript of 2.5 kb is detected in retinal pigmented epithelium of a 9‐day‐old chicken embryo.
Expression of Tyrosinase Gene in Transgenic Albino Mice: The Heritable Patterned Coat Colors
Authors: TANAKA SATOSHI , TAKEUCHI TAKUJI
Published: July 2006

To elucidate the regulatory mechanism for tyrosinase gene expression in vivo, we microinjected a mouse tyrosinase minigene, mg‐Qrs‐J, into the fertilized eggs of BALB/c albino mice. As a result, we obtained six pigmented founder mice that exhibited non‐standard coat color variations as well as the wild‐type phenotype. These founder mice were subsequently crossed with BALB/c albino mice to establish the transgenic lines. As a consequence, two primary lines and five sublines have been obtained from four of the six founder mice. We found that not only uniformly pigmented phenotypes but also patterned phenotypes were inherited by their descendants. The possible underlying mechanism of the patterned phenotypes is discussed.
Molecular Cascades in UV Induced Melanogenesis: A Central Role for Melanotropins?
Authors: PAWELEK JOHN M. , CHAKRABORTY ASHOK K. , OSBER MICHAEL P. , ORLOW SETH J. , MIN KENT K. , ROSENZWEIG KEN E. , BOLOGNIA JEAN L.
Published: July 2006

When human skin is exposed to ultraviolet (UV) light, a highly complex cascade of events ensues that culminates, among other things, in increased skin melanin content. From analyses at the tissue and cellular level, it has been shown that following exposure to UV light there is an increase in the number of active melanocytes in the basal layer of the epidermis, and individual melanocytes are stimulated to produce more melanin. In addition, the rate of transfer of melanosomes from melanocytes to keratinocytes is apparently increased, although the role of UV light in this process remains to be demonstrated. Recent biochemical evidence is reviewed on factors that regulate these processes. A plausible explanation for the effects of UV on pigmentation is that there are mechanisms in the skin for the orderly, regulated reception of UV signals that are then transduced to initiate the cascade. The signals involve both melanocytes and keratinocytes, and avail‐able evidence supports a model in which melanotropins and their receptors play a central role in the process.
Effect of Amphotericin B on Dopachrome Tautomerase Activity and Other Melanogenic Parameters in Cultured B16/F10 Melanoma Cells
Authors: PEINADO PALOMA , MARTÍNEZ‐LIARTE JOSÉ H. , SOLANO FRANCISCO , LOZANO JOSÉ A.
Published: July 2006

The antifungal reagent Fungizone (amphotericin B and deoxycholate) caused an activation in dopachrome tautomerase and dopa oxidase activities of B16/F10 melanoma cells at the routine concentration (2.5 μg/ml) used for preventing molds and yeast growth in cultures of animal cells. However, higher amphotericin B concentrations caused a significant cell death and the inhibition of enzymatic activities. At the optimal concentration of Fungizone, the enzymatic activities and melanin content were augmented as incubation time increased. The detergent sodium deoxycholate alone exerted no effect on these melanogenic parameters, eliminating the possibility that this detergent was partially responsible for melanogenic modifications produced by Fungizone. After withdrawal of Fungizone from the reaction medium, the recovery of melanogenic parameters to normal values was slower for DCT than for tyrosinase. The behavior of dopa oxidase was very similar to that reported by Johnson and Bagnara (Pigment Cell Res. 3, 173–175) for tyrosine hydroxylase.