bluuebunny/crossref_metadata_2025 huggingface dataset:
The Measurement of Gender-Role Attitudes
Authors: McHugh Maureen C. , Frieze Irene Hanson
Published: July 2006

This article reviews measures of gender-role attitudes with an emphasis on The Attitudes Toward Women Scale (AWS; Spence & Helmreich, 1972); the Sex Role Egalitarianism Scale (SRES; Beere, King, Beere, & King, 1984); the Modern Sexism Scale (MS; Swim, Aikin, Hall, & Hunter, 1995); the Ambivalent Sexism Inventory (ASI; Click & Fiske, 1996), and the Children's Occupational Activity Trait-Attitude Measure (COAT-AM; Bigler, Liben, Lobliner, & Yekel, 1995). The discussion of gender-role attitude measures focuses on the following themes: psychometric criteria; theoretical and conceptual distinctions among measures; domains of attitudes and behaviors included; relationship to other measures; and the meaningfulness and relevance of items. Gender-role attitude scales are viewed as measuring gender-role ideology in a particular sociohistorical context; context-specificity is viewed as contributing to the proliferation of scales, and as limiting the usefulness of scales across cultural and temporal boundaries.
More on The Structure of Male Role Norms
Authors: Fischer Ann R. , Tokar David M. , Good Glenn E. , Snell Andrea F.
Published: July 2006

This study assessed the structure of a widely used measure of masculinity ideology, the Male Role Norms Scale (Thompson & Pleck, 1986), using data from four samples of male college students (total N= 656) at two large, public universities (one Midwestern, one Eastern-Central). Exploratory factor analysis suggested a four-factor model best fit the data in the exploratory sample (sample 1; N = 210). The four factors were Status/Rationality, Antifemininity, Tough Image, and Violent Toughness. A series of confirmatory factor analyses on a validation sample (samples 2, 3, and 4; N = 446), tested four models based on theory (i.e., Brannon, 1976) and previous research (i.e., Thompson & Pleck, 1986). Results from Study 1, our exploratory analysis, indicated that the four-factor model derived from the exploratory sample in Study 1 provided the best fit for the validation sample data of all models tested and also provided a good fit in absolute terms, according to several model–data fit indices. Implications for the assessment of masculinity ideology and suggestions for future research are discussed.
Maternity Leave, Role Quality, Work Involvement, and Mental Health One Year After Delivery
Authors: Klein Marjorie H. , Hyde Janet Shibley , Essex Marilyn J. , Clark Roseanne
Published: July 2006

Employment status, maternity leave, and role quality were investigated as predictors of women's mental health one year after delivery. Home-makers and part-time and full-time employees did not differ on measures of depression, anxiety, anger, or self-esteem. There were no main effects of leave length. Distress was associated with job overload, role restriction, and infant distress. Leave length interacted with the relative salience of work and family, and employment status interacted with employment preference to predict distress. Depression was greatest among women relatively high in work salience when leaves were long. Anxiety and anger were greatest among women whose employment status was not congruent with their preferences. These interactions underscore the importance of individual differences in responses to leave and work.
Marriage and Depressive Symptoms
Authors: Culp Laurie N. , Beach Steven R. H.
Published: July 2006

This study examined gender differences in the configuration of components of intimacy in marriage and in the relationship of marriage to depression in a community sample of 260 men and women. We hypothesized that women's report of marital intimacy would include a distinct self-disclosure component, whereas this would be part of companionship in men's report of intimacy. Also, using self-in-relation theory, we hypothesized that self-esteem level would mediate the relationship between marital quality and depression for women but would moderate this relationship for men. Both predictions were upheld, suggesting a need to reformulate current models of the role of marital quality in depression to better capture the influence of gender.
“Like Chewing Gravel”
Authors: Merrick Elizabeth
Published: July 2006

The researcher's role in creating knowledge and interpretations is of critical concern as new research methods are developed. Recent attention has been given to the “implications of difference” on the research process; however, the processes of analysis/interpretation and presentation of research remain to be illuminated. Seeking to address this, I present my experiences as a White researcher of middle socioeconomic status (SES) conducting qualitative research about childbearing with several pregnant Black American adolescents of lower SES. Although the research process was consistent with qualitative research methods, initial analyses of the data led to findings that seemed far afield from the participants' worlds. I subsequently reanalyzed the data with the principles of a feminist epistemology (Harding, 1991) in mind. The impact of using this epistemology on the processes of analysis and interpretation and my presentation of the data are presented. The results support the importance of developing feminist methodology and epistemology and provide new direction for further work.
Negotiating the Life Narrative
Authors: Ceballo Rosario
Published: July 2006

This article explores two methodological issues that arise when researchers involve the women they study in the construction of life narratives. These issues are examined in the context of an interview-derived, life-narrative study of an African American social worker. First, the tension between presenting a neatly unified identity in a written text and acknowledging the contradictions within any person's life story are discussed from both the researcher's and participant's vantage point. The second issue addresses the dilemma that arises when the researcher and the research participant disagree about the meanings and interpretations garnered from the participant's life story. I contend that it is precisely at this moment that the research process has the potential to become a dialogue between theorists and that scholars can incorporate a woman's own theorizing about her life in the research. In concluding, several methodological suggestions are offered as broad guidelines for researchers planning a life-narrative study.
Alcohol and Sexual Aggression in a National Sample of College Men
Authors: Ullman Sarah E. , Karabatsos George , Koss Mary P.
Published: July 2006

Alcohol use prior to sexual assault by both offenders and their victims may be associated with the severity of sexual aggression men commit against women. Little research has explored the pathways (e.g., social context, behavior) through which alcohol may affect outcomes of sexual attacks. The present study analyzed the role of alcohol in sexual assaults ( N = 694) committed by men identified from a national sample ( N = 2,972) of male college students completing a survey. Interactions of alcohol use with assault variables did not suggest any synergistic role of alcohol use in predicting sexual aggression severity. Path analysis showed, however, that offender propensity to abuse alcohol and victim preassault alcohol use were each both directly and indirectly related to sexual aggression severity, whereas offender preassault alcohol use was not directly related to sexual aggression severity. This study suggests that alcohol use plays both direct and indirect roles in the outcomes of sexual assaults. Rape and alcohol abuse prevention efforts can benefit from incorporating information about alcohol's role in different assault contexts.
Perceptions of Women's Sexual Interest and Acquaintance Rape
Authors: Bondurant Barrie , Donat Patricia L. N.
Published: July 2006

Rape prevention and education efforts often focus on the need for clear communication regarding sexual intent between women and men. This approach is based on the underlying assumption that acquaintance rape is a relational issue resulting from miscommunication. Findings from two studies challenge that assumption. The first study demonstrates that men who self-report engaging in sexually aggressive behavior are significantly more likely to misperceive women's sexual intent than other men or women. The second study demonstrates that the cognitive, rather than affective, components of rape-supportive attitudes contribute to sexualized interpretations of women's behavior. Thus, it appears that the tendency to rely on miscommunication as a framework for understanding sexual assault may be deflecting attention from sexual overperceptions and the affectively based information processing among men who engage in sexually assaultive behavior.
The Adolescent Femininity Ideology Scale: Development and Validation of a New Measure for Girls
Authors: Tolman Deborah L. , Porche Michelle V.
Published: July 2006

This article describes the development and validation of the Adolescent Femininity Ideology Scale (AFIS) through three studies with racially, ethnically, and socioeconomically diverse early, middle, and late adolescent girls. Distinguished from feminine personality trait and feminine gender role, the concept of femininity ideology represents the individual-level construct that links individual females to social constructions of femininity. The AFIS measures the extent to which adolescent girls have internalized or resisted two negative conventions of femininity in two psychological domains: experience of self in relationship with others and relationship with one's body. Grounded in girls' own words, the 20-item scale is comprised of two subscales reflecting these domains. The AFIS has acceptable internal consistency and temporal stability. We demonstrate construct and concurrent validity, as well as discriminant validity from the Bern Sex Role Inventory (Bern, 1981) and the Attitudes Towards Women Scale for Adolescents (Galambos, Petersen, Richards, & Gitelson, 1985). We discuss the promise and limits of this new measure of gender ideology for adolescent girls.
The Psychosocial Well-Being of Black and White Mothers Following Marital Dissolution
Authors: McKelvey Mary W. , McKenry Patrick C.
Published: July 2006

This study proposed that African American cultural, social, and economic experiences would positively influence the psychosocial adjustment to marital dissolution of Black mothers as compared to White mothers. The study sample consisted of 235 Black and 662 White divorced or separated mothers from the National Survey of Families and Households. The mothers were not remarried and reported having at least one or more biological or adopted children, 18 years of age or younger, living in the home. Discriminant analysis (stepwise), after controlling for socioeconomic status and time since divorce or separation, indicated that Black mothers had higher levels of personal mastery and economic well-being and received greater formal support after divorce. Contrary to the hypotheses, White mothers received more informal support and evidenced earlier entry into dating than Black mothers. The findings document cultural variations in marital dissolution and the strengths of Black families in coping with this transition.
Normal Uveal Melanocytes in Culture
Authors: HU FUNAN , TERAMURA DINAH J. , MAH KUNIE
Published: July 2006

Normal uveal melanocytes of rhesus and cynomolgus macaques can be grown in culture for 3–9 months and subcultured a few times. Postnatal and adult choroidal melanocytes are terminally differentiated cells. They are melanin‐containing but not actively melanin‐synthesizing cells. They do not undergo cell division, nor do they incorporate tritiated thymidine, but otherwise they are metabolically active. Postnatal and young adult iridial melanocytes are metabolically more active than choroidal cells. They require a feeder cell layer for attachment and to be maintained in a healthy condition. An endothelial cell line established from a rhesus fetal choroid‐retina proves to be an effective feeder layer for adult iridial cells. Fetal uveal melanocytes divide slowly and usually require some stimulus and a special culture environment supplemented with 12‐O‐tetradecanolphorbol‐13‐acetate and cholera toxin. They can grow and differentiate in vitro. Iridial melanocytes grow and change into cells resembling postnatal choroidal melanocytes. Similar changes occur during development in utero. These findings further suggest that, in vivo, iridial melanocytes migrate and mature to become choroidal melanocytes.
Temporal Synthesis and Presentation of Antigens by Cultured B16 Melanoma Cells
Authors: GERSTEN DOUGLAS M. , PHILLIPS TERRY M. , HEARING VINCENT J.
Published: July 2006

Previous studies have demonstrated the presence of two distinct antigens, B700 and B50, which are unique to murine melanoma. One of these, B700 has been studied in detail, and is present on 5 different murine melanomas; it can function as a transplantation antigen in at least 3 of them (B16, JB/RH and K1735). The synthesis and presentation of these antigens has been studied as a function of cell culture conditions. Direct immunofluorescence studies of cells in serial culture indicate that the expression of B700 and B50 antigens at the cell surface and in the cytoplasm increases as a function of time in culture, over 1–5 days. By day 5, when the cells are confluent, all cells show some degree of antibody binding. Parallel 35S‐methionine pulse chase labeling experiments show that incorporation into Triton soluble proteins, and Triton insoluble SDS soluble proteins, increases to a peak at 3.5 days after subculturing, then decreases as the cells reach confluence. Incorporation into proteins shed into the culture supernatant continued throughout the time course of cell growth to confluence. However, as the cells become confluent, total protein synthesis shifts towards greater production of the antigens (both cellular and shed). The sum of the results suggest that tumor growth may succeed in vivo by the wholesale production of “decoy” antigens.
Inhibition of Tyrosinase Activity and Protein Synthesis in Melanoma Cells by Calcium lonophore A23187
Authors: FULLER BRYAN B.
Published: July 2006

Calcium ionophore A23187 lowers basal levels of tyrosinase and inhibits the MSH‐induced increase in tyrosinase in Cloudman S‐91 mouse melanoma cell cultures. lonophore at a concentration of 10–6 g/ml causes a 50% reduction in basal levels of tyrosinase and inhibits the MSH stimulated level of enzyme. lonophore A23187 also inhibits the PGEi mediated stimulation of tyrosinase, as well as the rise in enzyme activity observed in cells exposed to either theophylline (1 mM) or dbcAMP (10–4M). lonophore does not affect basal levels of cyclic AMP nor the elevated levels produced by either MSH or PGEi, suggesting then, that the antagonistic activity of A23187 is localized to a point in the pathway of tyrosinase activation distal to the formation of cAMP. lonophore causes a rapid and marked (> 50%) inhibition of cellular protein synthesis and it is possible that this calcium mobilizing compound may exert its inhibitory effects on tyrosinase activity by causing a general reduction in cellular translation. Since the inhibition of protein synthesis occurs in cells exposed to ionophore in either the presence or absence of calcium in the medium, it seems, likely that the ionophore may exert its effects by causing the release of calcium from intracellular sites.
Observations on the Pigmentation of the Pigeon Iris
Authors: OLIPHANT LYNN W.
Published: July 2006

There are three genetically controlled iris types found in the pigeon, two of which contain stromal pigment cells, the third lacks pigment cells. The yellow (gravel) and white (pearl) iris types have pigment cells that contain birefringent pigment granules (crystals) and are ultrastructurally similar to iridophores of poikilothermic vertebrates. Both these iris types contain guanine as a major “pigment” and, in addition, the yellow iris contains at least two yellow fluorescing pigments that are tentatively identified as pteridines. The pigment cells of the yellow and white irises are structurally identical differing only in the presence or absence of these yellow pigments. The stromal pigment cells of the white iris correspond in structure and pigment chemistry to classical iridophores although they lack strong irridescence and are therefore perhaps best considered leucophores. The pigment cells of the yellow iris can be considered “reflecting xanthophores” having the combined properties of both classical xanthophores and iridophore/leucophores.
Inhibition of UV Radiation‐Induced DNA Damage by a 5‐Methoxypsoralen Tan in Human Skin
Authors: YOUNG ANTONY R. , POTTEN CHRISTOPHER S. , CHADWICK CAROLINE A. , MURPHY GILLIAN M. , COHEN A. JEFFREY
Published: July 2006

Previously untanned buttock skin of 4 volunteers (skin type II; tan with difficulty as they sunburn easily) was treated with various sunscreen preparations and solar‐simulated radiation (SSR) or SSR alone for 2 weeks. One week later, the treatment sites were challenged with a DNA‐damaging dose of SSR—twice the minimal erythema dose (2 MED). Skin biopsy samples were assayed for the levels of unscheduled DNA synthesis (a measure of DNA damage), melanin distribution, and skin thickening. 5‐Methoxypsoralen‐containing sunscreen preparations plus SSR or SSR alone induced melanogenesis and increased the stratum corneum thickness, but only the former regimen afforded a high degree of protection against subsequent SSR‐induced DNA damage. 5‐Methoxypsoralen‐free sunscreen preparations plus SSR induced negligible tanning, skin thickening, and photoprotection. These findings are relevant to the risk‐benefit analysis of sun‐screen preparations, especially in skin type II, as they provide evidence that a 5‐methoxypsoralen‐induced tan is protective against the DNA‐damaging effects of solar UV radiation, and thus has the potential to reduce the carcinogenic risk of exposure to such radiation.
Evaluation of Different Procedures for the Dissociation of Retinal Pigmented Epithelium Into Single Viable Cells
Authors: VIELKIND URSULA , CRAWFORD BRUCE J.
Published: July 2006

Retinal pigmented epithelium (RPE) from 7‐day‐old chicken embryos (stages 29 to 31) was isolated and dissociated into single cells using different procedures. The results were assessed in two ways. (1) The yield of single RPE cells per embryo was determined, and their ability to form pigmented colonies in clonal culture was tested. The most efficient and gentle procedure included isolation of the RPE in EDTA solution, trypsinization at low temperature and low enzyme concentration in the presence of EDTA, followed by incubation in culture medium for up to 4 hr. The completely dissociated cells thus obtained had a much higher plating efficiency and more uniform pattern of colony growth and differentiation than those obtained under any other conditions tested. (2) The effects of different treatments on cell junctions and morphological integrity of the cells were determined by transmission electron microscopy. EDTA solution yielded excellent separation of the epithelial sheet from the mesenchyme by dissociating it from Bruch's membrane, but had little effect on the junctions between adjacent RPE cells. Trypsinization of the epithelium under various conditions separated the basal lateral cell borders and caused loss of gap junctions, but left many cells still joined by apical tight junctions. Final disruption of the tight junctions occurred during recovery of the trypsinized cells in culture medium and was accompanied by dedifferentiation of the RPE cells.
Demonstration of B700 Cross‐Reactive Antigens on Human and Other Animal Melanomas
Authors: GERSTEN DOUGLAS M. , HEARING VINCENT J.
Published: July 2006

B700 is a melanoma‐associated antigen originally detected by immunologic and biochemical criteria; it is expressed by several murine melanomas but is not detectable on any normal murine cells, or on murine nonmelanoma neoplasms. We have used antibodies raised against purified B700 to study the presentation of B700 and B700 cross‐reactive molecules on the surfaces of melanoma cells of various species and origins. The antibodies are shown to bind to all the melanoma cells tested, including five different murine melanoma lines (S91, JB/RH, JB/MS, K1735, and B16), three different B16 sublines (F1, F10, and BL6), three human, one hamster, and two swine melanoma cell lines. These results suggest the candidacy of B700‐like molecules as “pan‐melanoma” antigens.
Biosynthesis and Function of Melanins in Hepatic Pigmentary System
Authors: SICHEL GIOVANNI
Published: July 2006

In this report we show the most important results obtained from our study of the pigment liver cells of Amphibia and Reptilia.

Contrary to the cutaneous pigment cells that derive from the neural crest, the liver pigment cells, instead, derive from the Kupffer cells: this can be seen from the results obtained from labelled precursor incorporation experiments, not only in vivo but also in vitro, using surviving liver slices or isolated melanosomes.

Chemical analysis of both liver and cutaneous melanosomes reveal a great difference in their chemical composition, and this is in agreement with the different origins of these cells.

We therefore propose that: liver pigment cells of Amphibia and Reptilia should be classified as “Extra Cutaneous Pigment Cells from Histocytic Origin”.

As regards the function of melanins, we show that O2 is trapped by these substances.

Moreover, in my laboratory we have shown in several animal species, that the super‐oxide dismutase activity is inversely proportional to the quantity of melanin present; thus, we think that melanin could mime SOD activity.
Role of the Melanocyte in Epidermal Inflammatory and Immune Responses
Authors: NORDLUND JAMES J. , AMORNSIRIPANITCH SOMNUK , RHEINS LAWRENCE A. , ABDEL‐MALEK ZALFA A. , BOISSY RAYMOND E. , BELL MARY
Published: July 2006

The epidermis is composed of four major cell types in the mouse. In addition to keratinocytes and Langerhans cells, there are also melanocytes and Thyl+ lymphocytes. We propose that for the epidermis to maintain homeostasis, all four cell types must interact together in an integrated fashion. Vitiligo is a form of depigmentation that affects human subjects. Depigmentation is common in the animal kingdom. In at least several animal species, depigmentation is accompanied by loss of responsiveness of the epidermis to potent contact allergens like dinitrofluorobenzene. The C57Bl/Ler vit/vit mouse spontaneously depigments and is phenotypically similar to humans with vitiligo. We have studied this species extensively and have found that it has an isolated immune defect to contact allergens. In this report, we document that there is loss of epidermal melanocytes. Although there is a loss of epidermal contact sensitivity in this animal, other immune parameters such as dermal delayed‐type hypersensitivity are normal. We attribute this loss of immune sensitivity in the epidermis to be associated with loss of the melanocyte. We report and review in detail the many peptides and other types of inflammatory mediators that affect both melanocyte function as well as immune responsiveness.
Protein Kinase C and Melanocyte Transformation
Authors: BIRCH MARY , MEYSKENS F.L. , KORC MURRAY
Published: July 2006

Melanoma cells which have been isolated from metastatic melanoma tissue are able to survive and proliferate in serum supplemented media. In contrast, normal human melanocytes require the presence of growth stimulators if they are to survive in culture. A tumor promotor, 12–0‐tetradecanoyl‐phorbol‐13‐acetate (TPA) and substances that increase intracellular levels of cyclic‐adenosine‐monophosphate (cAMP), such as cholera toxin or isobutylmethyl xanthine, have been widely used for this purpose. The phorbol diester receptor was shown in 1982 to be the phospholipid‐ and calcium‐dependent enzyme protein kinase C (PKC). We therefore directed our studies to the role of PKC regulation in the growth of normal human melanocytes and their transformation. Our studies show that while melanoma cells are inhibited by TPA, the growth of normal melanocytes is stimulated in a dose‐dependent manner. The inhibitor, 1‐(5‐isoquinolinesulfonyl)‐2‐methyl‐piperizine dihydrochloride (H7), which has been found to be the most specific for PKC, had no effect on the growth of normal melanocytes, but inhibited the growth of melanoma cells in a dose‐dependent manner. PKC was isolated from the membrane and cytosol of normal melanocytes and melanoma cells. The basal (resting) levels of PKC activity in normal melanocytes was low compared to that measured in melanoma cells, and after short‐term (1 hour) treatment with TPA the PKC activity was greatest at the membrane, with the activity decreasing the cytosol. Upon prolonged (48 hours) treatment with TPA, this redistribution of activity continued in normal melanocytes and the total activity increased. In melanoma cells, however, the total PKC activity decreased, particularly in the membrane fraction. A difference in activity and distribution of the enzyme was also seen after short‐term (1 hour) treatment with H7. There was very little effect seen on PKC in normal melanocytes; however, the effect on melanoma cells was similar to that seen after 48 hours of exposure to TPA with a decrease in total activity, particularly in the membrane fraction. These results indicate that the regulation of PKC, in particular its activation by TPA, is altered during the transformation of normal human melanocytes
Murjne Anti‐Idiotypic Monoclonal Antibodies to Syngeneic Antihuman High Molecular Weight‐Melanoma Associated Antigen Monoclonal Antibodies: Development, Characterization, and Clinical Applications
Authors: KAGESHITA TOSHIRO , CHEN ZHI JIAN , KIM JIN‐WOO , KUSAMA MIKIHIRO , KEKISH ULANA MARIA , TRUJILLO TRACY , TEMPONI MASSIMO , MITTELMAN ABRAHAM , FERRONE SOLDANO
Published: July 2006

Following a discussion of the rationale underlying the selection of human melanoma to test the usefulness of anti‐idiotypic monoclonal antibodies in the therapy of solid tumors, the development of the anti‐idiotypic monoclonal antibody MoAb) MF11–30 is described. This antibody recognizes a private idiotope within the antigen‐combining site of the immunizing antihuman high molecular weight melanoma‐associated antigen MoAb 225.28. The results of a phase I clinical trial with the MoAb MF11–30 in patients with advanced melanoma are described. The lack of toxic effects and the minor responses in six patients suggest that these studies should be extended to a larger number of patients with an emphasis on the analysis of the mechanisms underlying the clinical response.
pH‐Dependent Interconvertible Forms of Mushroom Tyrosinase With Different Kinetic Properties
Authors: DEVI CHINTAMANENI CHAYA , TRIPATHI RAM KUMAR , RAMAIAH ABBURI
Published: July 2006

The lag in cresolase activity and inhibition by excess tyrosine of mushroom tyrosinase which was observed when assayed at pH 6.8 was found to be absent when assayed at pH 5.0. The absence of lag and inhibition by excess tyrosine of tyrosinase at pH 5.0 were brought about only after the enzyme was kept at pH 5.0, at 0–4deg;C, for 1.5 h. The enzyme kept at pH 5.0 for 1.5–3 h at 0–4deg;C when brought back to pH 6.8, acquires lag and inhibition by excess tyrosine when its activity was measured at pH 6.8. The pH‐dependent changes in the kinetic properties of the mushroom tyrosinase are similar to the pH‐dependent changes in the kinetic properties of tyrosinase from B‐16 murine melanoma and human skin, and thus appear to be a general property of tyrosinase from diverse sources.
Repigmentation of Vitiliginous Skin by Cultured Cells
Authors: BRYSK MIRIAM M. , NEWTON RICHARD C. , RAJARAMAN SRINIVASAN , PLOTT TODD , BARLOW ELISIA , BELL TRACE , PENN PHILIP , SMITH EDGAR B.
Published: July 2006

Epidermal cells from pigmented areas of a patient with vitiligo were cultured in MCDB‐153 medium, which supports the clonal growth of undifferentiated keratinocytes and melanocytes. The cells were grown on collagen‐coated substrata. After the cells reached semiconfluence, the composite of substratum and cells was emplaced onto dermabraded vitiliginous areas as a graft. Re‐epithelialization of the grafted areas was complete after 2 weeks. Repigmentation was evident after 1 month and continued over the observation period of several months. There was complete and normal differentiation of the graft, including a normal distribution of melanocytes in the basal layer. Ultrastructural studies showed a normal distribution of melanosomes in the melanocytes and showed keratinocytes that were indistinguishable from the uninvolved skin.
Neutron Capture Therapy Research in Australia
Authors: ALLEN BARRY J.
Published: July 2006

Neutron capture therapy research in Australia has continued to grow since the first Australia—Japan workshop in April, 1986. The support base has broadened and the wide range of contributing laboratories includes universities, research institutes, and hospitals. Considerable progress has been made in boron chemistry—an accurate boron assay technique has been developed, boron analogues of chlorpromazine and thiouracil have been synthesised or nearly so, and decaborane conjugation with monoclonal antibodies has been achieved to the required loadings. In vitro cell survival experiments are proceeding in the Moata reactor using human melanoma and mouse cell lines incubated with enriched boronophenylalanine and boron tetraphenyl porphyrins. Electron microscopy examination of radiation damaged morphology shows considerable differences between cell lines.

Progress with the nude mouse human melanoma model has been slow because of the lack of a reliable in vivo melanotic melanoma line, and the B16 mouse line is found to be more efficacious.

Tailored beam calculations for the 10 MW HIFAR reactor indicate the difficulty of obtaining a suitable therapeutic beam because of the generated gamma dose in the beam filters.

A new approach to NCT utilises the enormous cross section of 157Gd and the induced‐Auger effect which has been shown to cause double strand breaks in circular DNA.
Boronated Monoclonal Antibody 225.28S for Potential Use in Neutron Capture Therapy of Malignant Melanoma
Authors: TAMAT SWASONO R. , MOORE DOUGLAS E. , PATWARDHAN ADITI , HERSEY PETER
Published: July 2006

The concept of conjugating boron cluster compounds to monoclonal antibodies has been examined by several groups of research workers in boron neutron capture therapy (BNCT). The procedures reported to date for boronation of monoconal antibodies resulted in either an inadequate level of boron incorporation, the precipitation of the conjugates, or a loss of immunological activity.

The present report describes the conjugation of dicesium‐mercapto‐undecahydrododecaborate (Cs2B12H11SH) to 225.28S monoclonal antibody directed against high molecular weight melanoma‐associated antigens (HMW‐MAA), using poly‐L‐ornithine as a “bridge” to increase the carrying capacity of the antibody and to minimize change in the conformational structure of antibody. The method produces a boron content of 1,300 to 1,700 B atoms per molecule 225.28S while retaining the immunoreactivity. Characterization in terms of the homogeneity of the conjugation of the boron‐monoclonal antibody conjugates has been studied by gel electrophoresis and ion‐exchange HPLC.
Synthetic Approaches to a Carboranyl Thiouracil
Authors: WILSON J. GERALD
Published: July 2006

Thiouracil is selectively incorporated into melanotic murine melanomas during melanin synthesis. This selectivity makes thiouracil a likely vehicle for boron in the diagnosis and therapy of melanoma. Several synthetic routes to thiouracils bearing an alkyl decacarboranyl group attached to various positions on the ring have been investigated. The successful syntheses of three new alkynyl thiouracils and the conversion of one of them into a carboranyl thiouracil are described.
Morphological Changes in Human Melanoma Cells Following Irradiation With Thermal Neutrons
Authors: BARKLA DAVID H. , ALLEN BARRY J. , BROWN J. K. , MOUNTFORD M. , MISHIMA Y. , ICHIHASHI M.
Published: July 2006

Morphological changes in two human melanoma cell lines, MM96 and MM418, following irradiation with thermal neutrons, were studied using light and electron microscopy. The results show that the response of human malignant melanoma cells to neutron irradiation is both cell line dependent and dose dependent, and that in any given cell line, some cells are more resistant to irradiation than others, thus demonstrating heterogeneity in respect to radiosensitivity. Cells repopulating MM96 flasks after irradiation were morphologically similar to the cells of origin whereas in MM418 flasks cells differentiated into five morphologically distinct subgroups and showed increased melanization. The results also show that radiation causes distinctive morphological patterns of damage although ultrastructural changes unique to the high LET particles released from boron 10 neutron capture are yet to be identified.
Epinephrine‐induced Pigment Aggregation in Goldfish Melanophoroma Cells: Apparent Involvement of an Unknown Second Messenger
Authors: CHOU SHUI‐CHOU , TAYLOR JOHN D. , TCHEN T.T.
Published: July 2006

Using a goldfish‐derived melanized cell line, we attempted to determine the identity of the signal transduction system/second messenger for epinephrine‐induced aggregation of melanosomes in a goldfish cell line. The results show that the second messenger is unknown. It is not 1) influx of extracellular calcium, 2) release of intracellular stored calcium via the phosphoinositide pathway, 3) cGMP, or 4) decrease of cAMP. These results suggest that there is an unknown second messenger for this activity of epinephrine.
Metabolism of 4‐Hydroxyanisole: Identification of Major Urinary Excretory Products
Authors: PAVEL STANISLAV , HOLDEN JANET L. , RILEY PATRICK A.
Published: July 2006

The human metabolism of 4‐hydroxyanisole was investigated by the analysis of urine samples from melanoma patients treated with this substance. The samples were hydrolyzed with glucoronidase and/or arylsulphatase, extracted with ethyl acetate, and, after derivatization with pentafluoropropionylanhydride, analyzed by gas chromatography‐mass spectrometry. We were able to identify peaks by their retention times and mass spectra corresponding to 4‐hydroxyanisole, 3,4‐dihydroxyanisole, and two of its o‐methyl derivatives, namely, 3‐hydroxy‐4‐methoxy‐ and 4‐hydroxy‐3‐methoxyanisole. We also detected a peak of hydroquinone, which may have originated (at least partly) from 4‐hydroxyanisole. All the above‐mentioned compounds were excreted predominantly as sulphates and glucuronides. Only a small proportion of the substances was present in urine in an unconjugated form. Our results demonstrate that 3,4‐dihydroxyanisole is the most important metabolite of 4‐hydroxyanisole.
Thermochemotherapy for B16 Melanoma: Combination Therapy of Hyperthermia, Melphalan, and CCNU in Mice
Authors: VICENTE V. , GOMEZ M. , OCHOTORENA M.M. , CREMADES A. , CANTERAS M.
Published: July 2006

We studied, by means of quantitative histopathological methods, the changes that took place in B16 melanoma implanted into C57BL/6J mice after combination treatment of hyperthermia, melphalan, and 1‐(2‐chloroethyl)‐3‐cyclohexyl‐1‐nitrosourea (CCNU). The studies were made on animals sacrificed on days 11, 18, and 25 after implantation. Tumors in treated animals showed a progressive delay in growth, a noticeably reduced number of metastases, and diminution of prolixferative capacity. However, this treatment did not affect necrosis, stroma, capsule, or cell infiltration. Ultrastructurally, signs of cell damage were constantly present.
Characterization of Calcium Uptake in Chick Retinal Pigment Epithelium
Authors: SALCEDA ROCÍO , RIESGO‐ESCOVAR JUAN RAFAEL
Published: July 2006

45Ca uptake was studied in isolated chick retinal pigment epithelial cells. 45Ca was accumulated by a saturable, temperature‐dependent system with a KM of 400 μM and a Vmax of 0.13 μmoles/mg protein/min, which depends on the external sodium concentrations. The transport system was present early during embryonic development. RPE cells of three breeds of chicks with different degrees of pigmentation accumulated calcium proportionally to the melanin content of the cells, suggesting that pigment granules participate in the storage and regulation of intracellular calcium.
Radiosensitivity of Murine and Human Melanoma Cells: A Comparative Study With Different Models
Authors: YOHEM KARIN H. , SLYMEN DONALD J. , BREGMAN MARVIN D. , MEYSKENS FRANK L.
Published: July 2006

The in vitro radiosensitivity of one murine melanoma cell line (Cloudman S91 CCL 53.1) and three human melanoma cell strains (C8146C, C8161, and R83‐4) were studied. Cells were irradiated by single dose X‐rays and plated either in agar or on plastic. The survival curves were fitted by the single‐hit multitarget, two‐hit multitarget, and quadratic models. Multiple comparisons of the residual sum of squares suggested that the two‐hit model was clearly inferior to the single‐hit and quadratic models. No statistically significant difference was suggested for either the single‐hit or quadratic models. Furthermore, on examination of the differences in correlations between the observed and predicted values, the residual plots (observed minus predicted over dose) failed to suggest a clear advantage of either the single‐hit multitarget or the quadratic models. Either model could be recommended for analysis of in vitro radiation data.
Protein Kinase C and Linoleic Acid‐Induced Inhibition of Melanogenesis
Authors: ANDO HIDEYA , OKA MASAHIRO , ICHIHASHI MASAMITSU , MISHIMA YUTAKA
Published: July 2006

Linoleic acid has been shown to inhibit melanogenesis in cultured B16 mouse melanoma cells. We report here the possible involvement of protein kinase C (PKC) in linoleic acid‐induced inhibition of melanogenesis in B16 cells. A single PKC subspecies (α‐PKC) was detected in B16 cells. The enzyme was activated by linoleic acid in vitro. The effective concentrations at which PKC was activated (25 μM; maximum response) were consistent with those for the inhibition of melanogenesis in cell culture system. In addition, the permeable diacylglycerol 1‐oleoyl‐2‐acetyl glycerol that activates PKC also inhibits melanogenesis at 100 μM. These results suggest that activation of PKC plays a pivotal role in the linoleic acid‐induced inhibition of melanogenesis in B16 cells.
Stimulation of Cultured Iridophores by Amphibian Ventral Conditioned Medium
Authors: BAGNARA JOSEPH T. , FUKUZAWA TOSHIHIKO
Published: July 2006

That the ventral integument of adult frogs (Rana pipiens) contains factor(s) that stimulate iridophore expression (adhesion, morphologic appearance, proliferation) was demonstrated on iridophores derived from tadpoles of R. pipiens and Pachymedusa dacnicolor, and maintained in primary culture in a growth medium based upon Leibovitz's L‐15. Experimental growth medium (VCM) conditioned by a one‐hour exposure to pieces of ventral skin of adult R. pipiens induced iridophores to assume a broad and stellate appearance, to form confluent sheets, and to proliferate over a nine‐day period. Iridophores in control medium assumed long thin profiles, detached easily, and exhibited no signs of proliferation. Unknown cells containing reflecting platelets and unusual other organelles appeared uniquely in chromatophore cultures of P. dacnicolor in VCM. The intense stimulation of iridophore expression in VCM is consistent with the known inhibitory effect of this medium on melanization and with its purported role in the determination of dorsal/ventral pigment patterns of amphibians. The results are discussed in terms of a prevailing theory about pigment cell origins and development.
4‐Hydroxyanisole: Human Pharmacokinetics
Authors: BELCHER H.J.C.R. , BARSTED C.G. , DAWSON C.M.
Published: July 2006

The pharmacokinetic behaviour of 4‐hydroxyanisole (4HA) has been studied in ten female patients with recurrent malignant melanoma confined to the lower limb. Ten grams of 4HA was infused twice each day via a catheter placed in the common femoral artery for a maximum of 4 days. Blood samples were collected after the first and fourth infusions in all patients and the serum 4HA concentration assayed. Following infusion, the serum 4HA concentration declined in two phases, the half‐lives (t1/2) of the distribution and elimination phases being 6.3 and 70.9 min, respectively. The serum 4HA concentrations and area under the curve (AUC) declined significantly between the first and fourth infusions. There was a significant rise in the apparent volume of distribution (VD) of 4HA between these times but no change in the t1/2 of the elimination phase or the clearance rate. It is concluded that there is no evidence that enzyme induction influences the clearance of 4‐hydroxyanisole from the bloodstream in the short‐term. However, it may be appropriate to adjust dosage regimens to take account of the change in VD that occurs with time.
Mutational Analysis of the Human p53 Gene in Malignant Melanoma
Authors: VOLKENANDT MATTHIAS , SCHLEGEL UWE , NANUS DAVID M. , ALBINO ANTHONY P.
Published: July 2006

Nine metastatic melanoma cell lines and two melanocyte cell lines were analyzed for point mutations in highly conserved regions of the p53 gene. No mutations were detected in the two melanocytic cell lines and in eight melanoma cell lines. However, a C→T transition at codon 248, resulting in a substitution of tryptophan for arginine, was found in one melanoma cell line. On immunohistochemical staining, only this cell line showed reactivity for mouse monoclonal antibody 1801, which is immunoreactive with human p53 protein. The original paraffin‐embedded specimen from which this mutant cell line was established was obtained, and sequence analysis detected the identical mutation in the p53 gene as that seen in the derived cell line. This is the first report indicating point mutations in the p53 gene in malignant melanocytic tissues.
After Dopachrome?
Authors: PAWELEK JOHN M.
Published: July 2006

Dopachrome, an intermediate in melanin biosynthesis, exhibits some unusual properties. At physiologic pH (e.g., pH 6‐8) it is unstable and spontaneously loses its carboxyl group to form 5,6‐dihydroxyindole (DHI(and CO2. However, over this same pH range, if various metals or a melanocyte‐specific enzyme are present, it rapidly rearranges to its isomer form—5,6‐dihydroxyindole‐2‐carboxylic acid (DHICA)—which is far more stable than dopachrome in its ability to retain the carboxyl group. Whether or not the carboxyl group is retained could have important implications for the regulation of melanogenesis, since in the presence of oxygen DHI spontaneously forms a black precipitate, whereas DHICA forms a golden‐brown solution. The solubility of “DHICA‐melanin” is due to the presence of carboxyl groups, which provide negative charges and hydrophilicity. Thus, in vivo, the extent to which dopachrome is converted to DHI or DHICA may well influence the solubility and color of the melanin formed. The purpose of this article is to review recent findings in these areas and to discuss the possible significance of dopachrome conversion in the regulation of melanogenesis and color formation.

This review has explored events in the melanogenic pathway that are under regulatory control after the formation of dopachrome. No attempt was made to include the regulation of pheomelanin synthesis, although the same basic questions should exist for both pheo‐ and eumelanogenesis. It seems clear that the earlier concepts of melanogenesis, wherein tyrosinase was the only regulatory enzyme, are incorrect, at least for mammals. Elucidating the newly described pathways will take considerable research effort and ingenuity over the coming years.
Pigmentary System of the Adult Alpine Salamander Salamandra atra atra (Laur., 1768)
Authors: TREVISAN PIERLUIGI , PEDERZOLI AURORA , BAROZZI GIANCARLO
Published: July 2006

The pigmentary system of the skin from adult specimens of the black alpine salamander Salamandra atra atra was investigated by light microscope, electron microscope, and biochemical studies. Results were compared with those obtained in previous study of the subspecies Salamandra atra aurorae. Unlike Salamandra atra aurorae, which presents epidermal xanthophores and iridophores, Salamandra atra atra is completely melanized, presenting only epidermal and dermal melanophores. The melanosomes in both the epidermis and the dermis appear to derive from a multivesicular premelanosome similar to that in the goldfish, and the epidermal melanosomes are smaller than those in the dermis. Premelanosomes with an internal lamellar matrix were not observed.

The biochemical results have shown that in the ethanol extracts obtained from the skin in toto and from the melanosomes, pteridines and flavins are always present and are the same as those extracted from the black skin areas of Salamandra atra aurorae.
Evidence for Alpha‐MSH Binding Sites on Human Scalp Hair Follicles: Preliminary Results
Authors: NANNINGA P.B. , GHANEM G.E. , LEJEUNE F.J. , BOS J.D. , WESTERHOF W.
Published: July 2006

Alpha‐MSH, considered an important pigmentation hormone, binds to melanocytes and is thought to stimulate melanogenesis through a cyclic‐AMP‐dependent mechanism. The binding of alpha‐MSH to follicular melanocytes has been investigated in human hair of different colors, ranging from black to blond and senile white. Hairs were plucked, the follicles were cut off, and an alpha‐MSH binding assay, using a radiolabeled alpha‐MSH analogue, was performed on these bulbs. As controls of each assay, fragments of hairs of the same person were used. The results show a dose‐response relationship and the assay seems to be specific for alpha‐MSH, because other peptides such as ACTH, beta‐LPH and beta‐endorphins do not compete for binding sites as alpha‐MSH does. These binding sites seem to be present only on melanin synthesizing melanocytes, since the controls and follicles of senile white hair, which do not contain active melanocytes, show negative results. All the assays were performed on raw material, i.e., whole plucked hair follicles. This is the first time that binding sites for alpha‐MSH have been demonstrated on human scalp hair follicles. In addition, their presence was found to be associated with active melanin production; their absence was demonstrated on senile white hair follicles.
Materia Melanica: Further Dark Thoughts
Authors: RILEY P.A.
Published: July 2006

The view is advanced that melanogenesis arose evolutionarily as a detoxification pathway for intrinsically‐generated orthoquinones.

The primary impetus for the production of orthoquinones may have been their general antibiotic properties and the utility of these chemical species in forming covalent crosslinks between proteins, as illustrated by cuticular sclerotization in insects. It is argued that polymerization to give rise to visible pigments may have originated as a pathway for the inactivation of orthoquinones. The possible evolutionary advantages accruing from the generation of melanin are discussed with special reference to acuity of photoreceptors and the physico‐chemical properties of melanin, as well as the contribution of melanin to protective colouration or display.