bluuebunny/crossref_metadata_2025 huggingface dataset:
Sex-Role Egalitarian Ism Scale
Authors: King Lynda A. , King Daniel W.
Published: July 2006

The Sex-Role Egalitarianism Scale (SRES) was developed to measure attitudes toward the equality of women and men across content domains representing marital, parental, employment, social-interpersonal-heterosexual, and educational roles. The instrument exists in four versions: two alternate 95-item full forms and two alternate 25-item abbreviated forms. Reliability indices derived from a classical test-theory approach, multifaceted generalizability procedures, and an item-response theory-based analysis all support consistency or precision of measurement. Evidence for convergent, discriminant, and nomological validity is presented, along with a series of recommendations for future psychometric and substantive research using the scale.
Researching Gender-Role Ideologies Internationally and Cross-Culturally
Authors: Gibbons Judith L. , Hamby Beverly A. , Dennis Wanda D.
Published: July 2006

Although many studies have compared gender-role ideologies internationally and cross-culturally, few researchers have attended to cultural differences in the meaningfulness or conceptual equivalence of the scale items. The literature on the use of instruments internationally is reviewed with respect to potentially universal (etic) constructs and findings. Gender differences in attitudes and the domains in which gender-related behavior is expressed differ internationally. A potential universal dimension is represented by a modern, egalitarian ideology on the one pole and a traditional ideology on the other. Using scales developed in three cultural contexts, we demonstrate that ratings of meaningfulness are correlated with the use of scores distant from the midpoint. Specific recommendations for researchers include consultation with cultural informants and incorporation of culturally specific (emic) items.
Gender Differences in Internal Beliefs About Weight and Negative Attitudes Towards Self and Others
Authors: Tiggemann Marika , Rothblum Esther D.
Published: July 2006

Previous research has found that people with an internal weight locus of control (beliefs in self-control over weight) are more likely to join and stay in weight-loss programs and have higher self-esteem than those who have an external locus of control (e.g., belief that weight is due to luck, genes). There has been no research on how weight locus of control affects the self-esteem of people who are not average weight or not satisfied with their weight. The present study predicted that for people who are overweight, weight locus of control would be negatively related to self-esteem. The results confirmed this interaction between weight locus of control and weight on self-esteem for women, but not for men. The second prediction was that internal weight locus of control would have negative social consequences in terms of greater negative stereotyping of obese people, and this was also confirmed for women. Because weight loss is rarely permanent, it would seem important to change people's attitudes about the lack of control that they (and others) have over body weight.
Integrating Gender and Ethnicity into Psychology Courses
Authors: Madden Margaret E. , Hyde Janet Shibley
Published: July 2006

In this introduction to the special issue on teaching about gender and ethnicity in psychology, we consider the assumptions underlying an inclusive curriculum that pays attention to gender and ethnicity and address why such a curriculum has merit. We review empirical studies, assessing whether existing curricula are inclusive, and present an overview of the articles and the recurrent themes. These themes include the complexity of the interaction between ethnicity and gender; the difficulty of deciding which of the many possible ethnic groups to include in course material; the dominance of evaluative comparison in discussions of differences among groups; the interdisciplinary nature of research on ethnicity; and the tendency in psychology to ignore the importance of the power differences that confound analyses of the effect of ethnicity and gender.
Teaching Gender Issues in Asian American Psychology
Authors: Okazaki Sumie
Published: July 2006

This article presents a set of pedagogical approaches and suggested topics and materials for teaching gender issues in Asian American psychology. The experiences of contemporary Asian American women and men must be understood with an appreciation for the larger social, political, and historical contexts in which they live. Thus, several topics designed to “set the stage” for exploration of gender issues are presented. Central issues in teaching gender-related topics within Asian American psychology are discussed under the categories of gender roles, gender stereotypes, and gender differences. Instructors are encouraged to use multimedia resources and interdisciplinary approaches to promote critical thinking about the complex interactions of ethnicity, gender, and the larger sociocultural forces that shape Asian American women and men's psychological experiences.
Suspected Repressed Childhood Sexual Abuse
Authors: Sullins Carolyn D.
Published: July 2006

This article explores therapists' responses to clients' suspicions that they have repressed memories of childhood sexual abuse (CSA). Each participant was randomly assigned one of two vignettes, varied for gender, each concerning a client who suspects that he/she is a victim of CSA. Following the vignette, a series of questions regarding the client assesses the participants' ratings of diagnoses, treatment goals, treatment plans, appropriate responses, and validity of suspicions. Participants were significantly more likely to endorse a diagnosis of borderline personality disorder and endorse treatments focusing on present symptoms over treatments focusing on the client's past. Participants were unlikely to endorse controversial treatments, suggestive statements, or strong opinions regarding the client's suspicions of CSA. The client's gender had a significant effect on diagnoses only. These results do not support reports that many therapists neglect clients' current symptoms and instead focus on memories, use controversial techniques, make suggestive statements regarding abuse, or immediately assume that their clients have repressed memories.
Token Resistance to Sex
Authors: Muehlenhard Charlene L. , Rodgers Carie S.
Published: July 2006

According to the traditional sexual script, women—but not men—engage in token resistance to sex, refusing when they actually intend to engage in sex. Several studies have found that over a third of the college women sampled reported refusing sexual intercourse when they intended to engage in it. We asked 65 women and 64 men to write narratives describing their experiences conforming to the definition of token resistance used in previous studies. As in previous research, both women and men reported engaging in token resistance. However, most respondents apparently misunderstood the definition because they wrote narratives that did not meet this definition. These results refute the stereotype that most women—and only women—engage in token resistance to sex. Furthermore, these results cast doubt on prevalence data reported in previous studies. Results indicate that the overwhelming majority of women and men who say “no” to sex actually mean no.
The Sexual Double Standard
Authors: Gentry Margaret
Published: July 2006

To explore the operation of the sexual double standard, 111 men and 143 women evaluated either a male or female target, described in a fictitious interview as involved in either monogamous or multiple heterosexual relationships and depicted as engaged in either above average, average, or below average levels of sexual activity. Targets described as involved in multiple relationships or depicted as engaged in above average levels of sexual activity were evaluated less positively than targets in other conditions. Women presented as more sexually active were seen as more liberal and more assertive than other female targets. In this study the sexual double standard was not operating in the formation of overall evaluations of individuals, but it did exert influence on other judgments that people make about men and women.
Situation-Specific Assertiveness in the Epidemiology of Sexual Victimization Among University Women
Authors: Greene Dennis Mac , Navarro Rachel L.
Published: July 2006

Protective and risk factors for sexual victimization were examined in a sample of 274 undergraduate women. Assertiveness specific to situations with the opposite gender was protective at all three assessment times. Prior victimization, alcohol use, poor adjustment (as indicated by depression and anxiety), multiple sexual partners, and insecurity about relationships with the opposite gender were significant risk factors. Prevention efforts might be more effective if (a) behavioral practice of assertiveness was added to informational and attitudinal interventions; (b) assertiveness training focused specifically on relationships with the opposite gender; (c) medical and counseling services routinely assessed for prior victimization and other risk factors, and made appropriate referrals for women with victimization histories; and (d) alcohol education-programs were integrated with acquaintance-rape programs.
Understanding Graduate Women's Reentry Experiences
Authors: Padula Marjorie A. , Miller Dana L.
Published: July 2006

This multiple case study describes the experiences of reentry women in psychology doctoral programs at a major Midwestern research university and illustrates the usefulness of the qualitative case-study method in exploring women's experiences. Semistructured interviews were conducted with four women who were purposefully selected as information-rich participants. Observations and informal interviews were also conducted over a period of up to 2 1/2 years. Eight themes emerged from the data and have been labeled: the decision to return, expectations versus reality, measuring up, frustrations and difficulties, changing family relationships, the necessity of organization, “do it and get on with life,” and rewards. This article illustrates that case-study research can be a powerful tool for feminist researchers to document women's experiences.
“Names Can Never Hurt Me?”
Authors: Etaugh Claire E. , Bridges Judith S. , Cummings-Hill Myra , Cohen Joseph
Published: July 2006

Research has shown that a woman's selected title of address affects perceiver impressions of her (e.g., Dion, 1987). This study adds to our understanding of the effects of chosen identity labels on perceptions of women by examining impressions as a function of a married woman's surname use. A total of 222 female and male students at a private university read a brief description of a woman who, at the time of her marriage, decided to take her husband's name, keep her maiden name, or use a hyphenated name. Participants rated the stimulus person on 51 traits along 7-point rating scales. The woman who took her husband's name was perceived as less agentic and more communal than women who either kept their maiden name or hyphenated their name.
CONTRIBUTORS TO STRESS RESISTANCE: Testing a Model of Women's Work-Family Conflict
Authors: Bernas Karyn H. , Major Debra A.
Published: July 2006

This study integrated work-family research with the stress resource perspective and organizational leadership theory. Based on the premise that stress is a major contributor to work-family conflict, this research examined resources likely to reduce the stress and work-family conflict women experience. Family emotional support, leader-member exchange, and hardiness were explored as potential resources. The 206 participants were recruited in daycare centers, a business community, and a university setting. The sample was diverse in terms of ethnicity and occupation. However, the majority of the women were married (68%) with children (82%). Path analytic tests supported most of the relationships in the hypothesized model. Findings suggest that having a high-quality relationship with one's supervisor may have complex implications for work-family conflict.
Women's Attitudes Toward Men: an Integrated Threat Theory Approach
Authors: Stephan Cookie White , Stephan Walter G. , Demitrakis Katherine M. , Yamada Ann Marie , Clason Dennis L.
Published: July 2006

Three studies were conducted to measure the antecedents of women's attitudes toward men using the integrated threat model. Four types of threats were hypothesized to produce negative attitudes toward men: (1) realistic threat based on threats to women's political and economic power, (2) symbolic threat based on value differences, (3) intergroup anxiety experienced during social interaction with outgroup members, and (4) negative stereotypes of men. Negative contact was hypothesized to increase the perception of all four threats as well as to affect attitudes directly. The findings suggest that symbolic threat, intergroup anxiety, and negative contact are the strongest predictors of negative attitudes toward men. Contrary to expectation, realistic threat may not be important to women's attitudes toward men.
Phosphorylated Mixed Isomers of l‐Dopa Increase Melanin Content in Skins of Skh‐2 Pigmented Hairless Mice
Authors: AGIN PATRICIA POH , SAYRE ROBERT M. , PAWELEK JOHN M.
Published: July 2006

Dopa phosphates, a new class of compounds, contain phosphate‐ester linkages at the 3‐ and/or 4‐ positions of the phenylalanine ring of l‐dopa. Dopa phosphates have been shown to increase pigment production in the epidermis of hairless mice. Groups of Skh‐2 pigmented hairless mice were treated topically with various concentrations of dopa phosphates daily for five weeks. Half of each group received suberythemal UVB radiation three times weekly for four weeks from a bank of filtered FS20 lamps. UVB and dopa phosphates alone each caused a modest increase in epidermal pigmentation. However, treatment of mice with dopa phosphates plus UVB radiation resulted in a marked increase in pigmentation, greater than with either treatment alone. The optimal concentration of dopa phosphates was 0.01% (100 μg/ml Tris‐glycerol buffer) whether or not they were applied in conjunction with UVB radiation. Histological analyses revealed that dopa phosphtes and UVB radiation each caused an increase in the number of pigmented melanocytes in the epidermis. Control groups treated with Tris‐glycerol buffer alone, or buffer containing l‐phenylalanine or l‐dopa showed no significant changes in pigmentation. Our results indicate that dopa phosphates stimulate the production of melanin and affect the development and distribution of melanocytes in the skin of Skh‐2 mice. By these criteria, dopa phosphates and UVB act in a similar manner to increase melanin content in the skin. The processes may be related to those recently observed in cultured mouse melanoma cells where dopa phosphates are incorporated into melanin, presumably following enzymatic hydrolysis by cellular phospha‐tases with the resultant production of l‐dopa and inorganic phosphate.
Eumelanin Causes DNA Strand Breaks and Kills Cells
Authors: HILL HELENE Z. , HILL GEORGE J.
Published: July 2006

Synthetic eumelanin prepared by autooxidation of D,L‐DOPA causes DNA strand breaks, as determined by alkaline elution after cell lysis with detergent and proteolysis, in B16CL4 mouse melanoma cells. The melanin is toxic to the cells in the range of doses that causes strand breaks. When the melanin was incubated with the cells at 37°C in tissue culture medium, it was maximally effective after 15 to 20 min at causing strand breaks in the DNA. The extent of damage is concentration dependent, but the effect plateaus at 1 mg/ml. The nature of the interaction of the cellular DNA with melanin is consistent with strand breaks, not DNA‐DNA crosslinks. The strand break damage is repaired, even in the continued presence of melanin, but repair is more rapid if the cells are washed and the melanin is removed. The form of the melanin is important for obtaining the effect. Sonication for 3 min abrogates the effect to a considerable extent, and repeated cycles of sonication can completely destroy the activity. Lost activity returns slowly with storage at 4°C. Melanin is more effective at damaging DNA in a protein‐free medium. It is also DNA‐damaging at 4°C, but less so than at 37°C. Preliminary studies indicate that the strand breaks caused by melanin are additive with those caused by ionizing radiation.

The extent of DNA strand breaks and alkali‐labile sites caused by several other melanins was also determined. Some melanins did not cause frank strand breaks, but were active in causing alkali‐labile sites. It is concluded that eumelanins are potentially genotoxic, and their protective effects in vivo must be possible by virtue of their chemical and physical relationships with other molecules and structures within the cell.
Ultraweak Photon Emission in Model Reactions of the In Vitro Formation of Eumelanins and Pheomelanins
Authors: SŁAWIŃSKA DANUTA , SŁAWIŃSKI JANUSZ
Published: July 2006

Ultraweak luminescence in the spectral region 300–660 nm is generated in the enzymatic (tyrosinase EC.1.14.18.1) and autooxidative polymerization of l‐DOPA, 5‐S‐cys‐teinyl‐DOPA, and l‐DOPA + cysteine to eumelanins and pheomelanins, respectively. Using sensitive calibrated single photon counting equipment, the photon emission intensity I and quantum yield φ have been measured: I = 10–100 hν/s cm3, φ≤ 10–13 for enzymatic reactions, and I = 500–3000 hν/s cm3, φ≥ 5 × 10–12 for autooxidative ones. 5‐S‐cysteinyl‐DOPA and cysteine exhibit diminished I and φ‐values relative to DOPA. Tests with chemiluminogenic probes‐luminol and lucigenin, SOD, catalase, peroxidase, H2O2, and spectrophotometric measurements indicate that photon emission is associated with degradative oxidations of melanin subunits by means of active oxygen species as H2O2 and O2.
Electron Microscopic Evidence for Stimulation of Melanosomal Maturation by Lysosomotropic Agents and Monensin in Cultured B16 Mouse Melanoma Cells
Authors: OIKAWA ATSUSHI , SAEKI HISAAKI , AKIYAMA TOYOKO , MATSUMOTO JIRO
Published: July 2006

Mouse melanoma cells, B16‐C2M in monolayer culture were treated with either lysosomotropic agent, 10 mM NH4Cl, or 20 μM chloroquine, an ionophore, or 10 μm monensin for 3 h at 37°C, and examined with regard to the site of melanin deposition and numbers of melanized (type 1) and unmelanized (type 2) melanosomes under a transmission electron microscope. The numbers of these two types of melanosomes were counted on electron micrographs of thin sections of 20 to 40 cells for each experimental group and expressed in terms of number per unit area of sectioned cytoplasm. Although most melanosomes were largely swollen in monensin‐treated cells, melanin deposition was apparently confined in melanosomes in all experimental groups. The compound melanosomes were scarcely found. The mean population density (number per unit cytoplasmic area) of type 1 melanosomes was highest in the NH4Cl‐treated cell group followed by monensin‐treated, chloroquine‐treated, and control cell groups. When the relative abundance of type 1 melanosomes was expressed as a fraction of total number of type 1 and 2 melanosomes (melanosomal maturation index, MMI), the differences were much more evident. Type 1 melanosomes were found in every cell (MMI ≠ 0) of the groups treated with NH4Cl and chloroquine only, which suggested the existence of a subpopulation of cells responsive to lysosomotropic agents but not to monensin in regard to melanosome maturation. All these findings indicate that the stimulation of melanogenesis proceeds mainly through maturation of preexisting melanosomes under these conditions.
Ocular Pathology in the Minimally Depigmented Subline of the Vitiliginous Smyth Chicken
Authors: BOISSY RAYMOND E. , GECKS SALLY , SMYTH J. ROBERT , NORDLUND JAMES J.
Published: July 2006

Choroidal melanocytes and the retinal pigmented epithelium (RPE) were studied morphologically and histochemically in the Smyth chicken, an avian model for human vitiligo. The sequence of cytological events occurring in the ocular tissue of minimally depigmented Smyth birds was determined. Abnormalities of melanocytes and the associated inflammation was least severe in peripheral areas of the choroid and most pronounced in the back of the eye at the base of the optic nerve head. In the peripheral choroid, morphologically normal melanocytes and an occasional mononuclear leukocyte were observed. However, some of these morphologically normal melanocytes histochemically demonstrated atypical tyrosinase activity at the trans area of the Golgi apparatus. Toward the back of the eye, the melanocytes first appeared swollen and had retracting dendrites. Ultrastructurally these melanocytes demonstrated an increase in extramelanosomal cytoplasm. Later, melanocytes became spherical and had membrane bound, autophagosome‐like compartments of pigment granules. As the melanocyte injury progressed, macrophages invaded the tissue and phagocytized melanocytic dendrites. These were followed by numerous plasma cells. Eventually, the back of the eye contained no pigment and was infiltrated with numerous mononuclear inflammatory cells. The retinal pigment epithelium also demonstrated a gradient in the degree of destruction, related to its topography. These cytological features consisted of the retraction of apical RPE processes, the disappearance of the basal plasma membrane infoldings, and the replacement of Bruch's membrane by collagen‐like fibrils. These results demonstrate that the uveitis which develops in vitiligo appears to be a consequence of an inherent choroidal melanocyte defect.
Major Primary Cytotoxic Product of 4‐Hydroxyanisole Oxidation by Mushroom Tyrosinase Is 4‐Methoxy Ortho Benzoquinone
Authors: NAISH S. , HOLDEN J.L. , COOKSEY C.J. , RILEY P.A.
Published: July 2006

It has been shown previously that the initial product of mushroom tyrosinase‐catalysed oxidation of the monophenol 4‐hydroxyanisole (4HA) is 4‐methoxy ortho benzoquinone (4‐MOB). This study presents evidence that 4‐MOB is primarily responsible for the cytotoxicity of 4HA oxidation products in vitro. Equivalent toxicity in a model system was produced by products of tyrosinase catalysed oxidation of 4HA and by synthetic 4‐MOB. Cytotoxicity was estimated both by a blebbing assay and by plating efficiency of exposed cells. HPLC analysis of the reaction mixture revealed a positive correlation between cytotoxicity and 4‐MOB concentration.
Ultraviolet Radiation Acts as an Independent Mitogen for Normal Human Melanocytes in Culture
Authors: LIBOW LESTER F. , SCHEIDE SARA , DeLeo VINCENT A.
Published: July 2006

Identification of growth factors for normal human melanocytes has been significantly aided by the recent development of in vitro culture systems for this cell. Utilizing such a system, we studied the effect of ultraviolet radiation (UVR) on both melanocyte growth and melanization by incorporation of 3H‐thymidine and 3H‐L‐dihydroxyphenyl‐alanine (3H‐DOPA), respectively. H‐thymidine incorporation was found to be significantly stimulated during the first 24 h following a single irradiation. 3H‐DOPA incorporation was stimulated after a delay of 2 days postirradiation.

Whereas UVR has long been known to induce melanocyte proliferation in vivo, these studies show that UVR can act as a mitogenic stimulus for this cell independent of the cutaneous environment. UVR can thus be added to a growing list of growth factors for epidermal pigment cells and is the only physical agent conclusively shown to act as a mitogen. Included in this list are substances that act via stimulation of the CAMP‐kinase or protein kinase systems such as cholera toxin and phorbol esters. UVR is postulated to induce melanocyte proliferation by modulation of these second messenger pathways. With recent evidence linking growth factors, oncogenes and malignant transformation, this study supports the association between UVR exposure and the development of malignant melanoma, and suggests mechanisms whereby UVR may contribute to malignant transformation of this cell.
Melanocytes in Human Embryonic and Fetal Skin: A Review and New Findings
Authors: HOLBROOK KAREN A. , VOGEL ARTHUR M. , UNDERWOOD ROBERT A. , FOSTER CAROLYN A.
Published: July 2006

Melanocytes account for approximately 5–10% percent of the cells in adult epidermis. Unlike the ectodermally derived keratinocytes, they originate in the neural crest and migrate into the epidermis early in development. There has been an interest in melanocytes in developing human skin since the late 1800s, when concentrated pigmented cells were identified in the sacro‐coccygeal skin of Japanese fetuses. This observation led to speculation and subsequent investigation about the racial nature of the melanocytes in this site (the Mongolian spot), the presence of melanocytes in fetuses of other races, the timing of appearance of these cells in both the dermis and epidermis, and their origin. The early investigators relied primarily on histochemical methods that stained either the premelanosome or the pigmented melanosome, or relied upon the activity of tyrosinase within the melanosome to effect the DOPA reaction. Studies by electron microscopy added further documentation to the presence of melanocytes in the skin by resolving the structure of the melanosome regardless of its state of pigmentation. All of these methods recognized, however, only differentiated melanocytes. The thorough investigations of melanocytes in the skin from a large number of black embryos and fetuses by Zimmerman and colleagues between 1948 and 1955 provided insight into the time of appearance of melanocytes in the dermis (10–11 weeks' menstrual age) and the epidermis (11–12 weeks) and revealed the density of these cells in both zones of the skin of several regions of the body. The precise localization of the melanocytes in the developing hair follicles was contributed by the studies of Mishima and Widlan (J Invest Dermatol 1966; 46:263–277). More recently, monoclonal antibodies have been developed that recognize common oncofetal or oncodifferentiation antigens on the surface or in the cytoplasm of melanoma cells and developing melanocytes (but not normal adult melanocytes). These antibodies recognize the cells irrespective of the presence or absence of melanosomes or their activity in the synthesis of pigment and therefore are valuable tools for re‐examining the presence, density, and distribution patterns of melanocytes in developing human skin. Using one of these antibodies (HMB‐45), it was found that dendritic melanocytes are present in the epidermis between 40 and 50 days estimated gestational age in a density comparable with that of newborn epidermis and are distributed in relatively non‐random patterns. A number of questions about the influx of cells into the epidermis, potential reservoirs of melanoblasts retained within the dermis, division of epidermal melanocytes, and the interaction of melanocytes and keratinocytes during development remain unresolved. The tools now appear to be available, however, to begin to explore many of these questions.
Regulation of Melanogenesis in Melanocytes
Authors: MOELLMANN GISELA , SLOMINSKI ANDRZEJ , KUKLINSKA ELIZABETH , LERNER AARON B.
Published: July 2006

Melanogenesis refers to the biosynthesis of melanin pigment in pigment cells called melanocytes. Melanins are mixed biopolymers formed during a series of oxidation/reduction reactions that are initiated by the enzymatic hydroxylation of L‐tyrosine to L‐dopa. In living cells, melanogenesis is limited to melanosomes, the membrane bounded microscopic secretory granules of melanocytes. Melanosomes may be secreted into the environment as, for example, from the squid's ink gland; or be transferred to neighboring cells, such as the keratinocytes in human skin and hair; or they may remain within the pigment cell and change only their subcellular localization, as in the rapidly color‐changing dermis of lower vertebrates.

Regulation of the melanocytic phenotype involves synthesis of the biosynthetically active subcellular apparatus of melanogenesis, premelanosomes and tyrosinase, and the utilization of the final product, melanized melanosomes, in the translocation and secretory processes mentioned above. Genetic information for this regulation is stored in the nuclear genome whose expression is controlled by the intra‐ and extracellular environment.

As premelanosomes become biosynthetically active, they mature into melanosomes by fusing with vesicles derived from the trans‐Golgi network and the plasmalemma, thereby internalizing and incorporating contents and membrane components from inside the cell and the cell surface. In the process, melanosomes become acidified. The thesis pursued in this review explores the importance of the melanosome as the final common pathway of regulation of melanin biosynthesis.
The BULT Melanoma: A Spontaneous Transplantable Tumor in Mice
Authors: QUEVEDO WALTER C. , DYCKMAN JACOB , HALABAN RUTH , MOELLMANN GISELA E. , COWAN JANET M. , HOLSTEIN THOMAS J.
Published: July 2006

The BULT melanoma originated at Brown University as a spontaneous, small black nodule on the tail of an adult female mouse of the LT/Ch strain. Histological examination of a portion of the tumor indicated that it was intradermal and consisted predominantly of heavily melanized, ovoid to fusiform cells with melanin‐laden macrophages scattered among them. The BULT melanoma has been maintained in LT/Ch mice for approximately 5 years by periodic transplantation, at first subcutaneously on the flanks and, more recently, intramuscularly in the hind legs. The shift in transplantation site was made following a marked decline in the growth of subcutaneous grafts.

The transplants have retained the uniform deep‐black melanization and general histology of the primary melanoma. Numerous melanosomes at all stages of development are found within the melanoma cells. DOPA‐positive cytoplasmic vesicles are abundant. Occasional autophagic vacuoles containing clusters of melanosomes are also present. A few metastases from the transplanted melanoma have been observed in lymph nodes and on one occasion in the lungs. When grown in vitro, BULT melanoma cells do not require special growth promoting agents (e.g., TPA; cAMP) in order to proliferate. The BULT melanoma differs in one or more respects from each of the other three transplantable spontaneous mouse melanomas widely used in cancer research. In addition, it arose in a strain of mice characterized by the spontaneous death of melanocytes while the latter are engaged in synthesizing eumelanin within hair follicles.

Karyotypic analysis of cultured cells showed a modal chromosome number of 68 with a range of 58–72 chromosomes.
Paradox of ras Oncogenes in Malignant Melanoma
Authors: ALBINO ANTHONY P.
Published: July 2006

Our studies over the past several years have concentrated on the role of oncogenes in the pathogenesis of malignant melanoma. Our objectives have been i) to determine the status of oncogene and proto‐oncogene activation and expression during specific clinically defined stages of melanoma; ii) to determine if these genes are involved in the induction, maintenance, and/or metastatic potential of melanoma cells; iii) to decipher the relationship of neoplastic transformation to differentiation in this disease; and iv) to determine the nature and timing of specific events which disrupt the normal functioning of the melanocyte. The experiments are intended to test the concept that multiple, cooperating, independently activated oncogenes are involved in the evolution of malignant melanoma. The range of data we have accumulated to date suggests a definite, but complex, role for oncogenes in the development of melanoma and points to a probable interrelatedness of melanocyte‐melanoma cellular differentiation programs and the process of malignant transformation. Further, our research has detailed a specific sequence of transformation‐related biological and biochemical events occurring in vitro in the human melanocyte in response to ras oncogenes, and has generated information suggesting the presence of, as yet, undefined genetic elements in melanoma.

Our work has evolved along a broad front, and we have analyzed the status of a large series of oncogenes in a range of melanomas and related tissues. However, in this brief review we will limit our focus to the ras gene family and discuss the data from my group and others which suggests not only a complex role for ras oncogenes in the etiology of melanoma but also a paradoxical one.
Melanoma Antigen and Transforming Gene
Authors: TAGAWA MASATOSHI , SAKAMOTO TOHRU , OKITSU AKIRA , TAMURA YOSHIO , IMAI KENJI , MATSUBARA HISAHIRO , TANIGUCHI MASARU
Published: July 2006

We summarize our recent studies on the analysis of melanoma antigen and the melanoma gene recently cloned. The melanoma antigen analyzed by syngeneic monoclonal antibodies is composed of a complex of GM3 ganglioside and protein molecules. The epitope recognized by antimelanoma cytotoxic T lymphocytes seemed to be the combinatorial determinants of GM3 and proteins, whereas the epitope for the suppressor T cells was found to be solely GM3 (NeuAc). The genomic DNA controlling the melanoma antigen was recently isolated and was found to possess transforming activity. The structure of this transforming gene is discussed based on the sequence data of the corresponding cDNA clone.
Monoclonal Antibody Against a Melanosomal Protein in Melanotic and Amelanotic Human Melanoma Cells
Authors: McEWAN MAX , PARSONS PETER G. , MOSS DENIS J. , BURROWS SCOTT , STENZEL DEBBIE , BISHOP CHRIS J. , STRUTTON GEOFFREY M.
Published: July 2006

BALB/c mice were immunized with tyrosinase, partially purified in two stages from a human melanoma cell line. A hybridoma was obtained which produced monoclonal antibody (MoAb 1C11) reactive with 8/10 melanoma cell lines and 10/10 primary cultures of human melanocytes, neval cells, and melanomas. Immunoreactivity correlated to a certain extent with tyrosinase activity but not with melanin content. No crossreactivity was obtained with neuroblastoma, medulloblastoma, fibroblasts, keratinocytes, lymphoid cells, or murine melanomas. Purification of the antigen directly from cell lysates with a MoAb 1C11 CNBr‐Sepharose affinity column gave a green‐brown protein of 56 kDa with no detectable tyrosinase activity. This protein was therefore different from 60 kDa active tyrosinase, identified by enzyme activity and Western blotting with a MoAb derived previously (MoAb 5C12). Unlike 5C12, 1C11 reactivity was not destroyed by pretreatment of the antigen with periodate. Immunogold labelling showed that the 1C11‐reactive antigen was associated with melanosomes, and there was close correlation between 5C12 and 1C11 reactivity in resistance to trypsin and in staining various melanocytic cell populations. MoAb 1C11 may therefore recognise a polypeptide epitope in a molecule closely linked to melanin biosynthesis.
Isolation and Characterization of a Novel Yellow Pigment from Human and Primate Tissue
Authors: HORTON F. K. , MOWER H. F.
Published: July 2006

A novel lipophilic yellow pigment has been isolated from human and primate tissue. Field‐desorption mass spectrometry suggests a molecular ion of mass 645–700, and electron‐impact mass spectrometry gives a major fragment ion at 603.5348, which is consistent with the elemental composition C37H69N3O3. The ultraviolet/visible spectrum has two major absorption peaks at 423.6 nm and 398.8 nm and a smaller peak at 377.8 nm. The adrenal gland contains the highest concentration of the pigment; it is also present in the colon, kidney, lung, spleen, and stomach tissue. It is not present in brain or liver. The pigment has not been detected in the rat, mouse, cow, pig, or dog.
Occurrence of Melanin Granules and Melanosynthesis in the Kidney of Sparus auratus
Authors: ZUASTI ADELINA , JARA JOSE R. , FERRER CONCEPCION , SOLANO FRANCISCO
Published: July 2006

An optical, ultrastructural, and biochemical study of the melanin accumulation nodules found in the kidney of the teleost fish Sparus auratus is presented. These nodules are randomly distributed in the interstitium of the renal tissue. They are formed by large aggregates of cells replete with melanin granules. The melanin granules occur singly or also in aggregates inside the cells. Most of the granules are electron‐dense, but sometimes small electron‐lucent spaces within them can be seen. Some secondary lysosomes and dendritic processes can also be observed. Biochemical studies have proved for the first time the existence of measurable tyrosinase activity in those nodules. That activity was assayed using three methods: tyrosine hydroxylation, dopa oxidation, and melanin formation. Furthermore, inhibitors of well‐characterized plant and animal skin tyrosinases were effective agents for inhibiting those activities in fish kidney preparations. This finding supports the notion of the existence of true tyrosinase in the melanin accumulation nodules of this tissue. Taking into account the results obtained, the origin and functions of the melanin‐containing cells found in the teleost fish kidney are discussed
Antioxidant Enzymatic Systems in Pigment Tissue of Amphibia
Authors: GEREMIA ERNESTO , CORSARO CONCETTA , BARATTA DANIELA , SANTORO CARMEN , SCALIA MARINA , SICHEL GIOVANNI
Published: July 2006

Superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase activities in pigmented and unpigmented liver tissues of frog and albino rat, respectively, were studied.

Our results show that pigmented tissue is lacking in manganese superoxide dismutase activity and that the main enzymatic activity utilized in the cytosol by pigmented cells to reduce the hydrogen peroxide to water is represented by catalase; on the contrary, for the same reaction, the cells of albino rat liver primarily utilize the glutathione peroxidase activity. Both a low glutathione peroxidase activity and a low glutathione reductase activity were found in pigmented tissue of frog liver when compared with unpigmented tissue of rat liver.

In light of our results, we also report a hypothetical interrelationship between melanin and reduced glutathione: We believe that in pigmented cells the melanin could act as a reducing physiological agent replacing the glutathione in the reduction of hydrogen peroxide. This reducing action of melanin could cause a diminished need for GSH and therefore could provoke the low glutathione peroxidase and reductase activities in pigmented tissue.
Complex Formation of p‐Boronophenylalanine With Some Monosaccharides
Authors: MORI YOSHIHIRO , SUZUKI AKIO , YOSHINO KAZUO , KAKIHANA HIDETAKE
Published: July 2006

To increase the solubility of p‐boronophenylalanine (p‐bpa) in neutral pH solution, the complex formation of p‐bpa with some monosaccharides has been studied by 11B‐NMR and UV spectroscopy. The complex formation constants (log K) obtained by the UV method in pH 7.4 solution are 2.43 (fructose), 2.19 (mannitol), 1.28 (galactose), 1.10 (mannose), and 0.85 (glucose), respectively. One hundred milligrams of p‐bpa is able to dissolve in 3 ml of 0.3 M fructose solution at pH 7.98. Based on the results obtained, the behavior of p‐bpa‐monosaccharide complexes in vivo after injection of the complex solution is described.
Altered Glycosylation of Surface Glycoproteins in Tumor Cells and its Clinical Application
Authors: KOBATA AKIRA
Published: July 2006

Appearance of large Asn‐linked sugar chains in the surface glycoprotein is one of the most widely found phenomena in malignant cells and is called the Warren‐Glick phenomenon. Comparative study of the sugar chain structures of the surface glycoproteins of cultured cells and their malignant transformants revealed that the altered glycosylation is induced by enhancement of N‐acetyl‐glucosaminyltransferase V. The change seems to be highly correlated with the metastatic potential of tumor cells.
Tyrosinase Activity in the First Coat of Agouti and Black Mice
Authors: MOVAGHAR MAHVASH
Published: July 2006

Tyrosinase activity was compared in the skin and hair bulbs of young black and agouti mice between 4 and 12 days old. Differences in activity were found to be maximal in both the hair and skin at the time of yellow pigment synthesis in agouti mice. Histological examination suggested that the number of dopa‐positive melanocytes is similar in the hair bulbs of agouti and black mice. The level of SH‐compounds in the hair bulb was examined and found to be elevated in agouti tissue at the time of phaeomelanin formation. It was shown that sulphydryl compounds such as cysteine and glutathione have an inhibitory effect on tyrosinase, and it is possible that the elevated levels of SH‐compounds are responsible for a reduction in tyrosinase activity in agouti mice. In agouti hair bulbs, this effect can be reversed in vitro by addition of copper.
Characterization of IIB‐MEL‐J: A New and Highly Heterogenous Human Melanoma Cell Line
Authors: GUERRA LILIANA , MORDOH JOSE , SLAVUTSKY IRMA , LARRIPA IRENE , MEDRANO ESTELA E.
Published: July 2006

A highly heterogeneous cell line, IIB‐MEL‐J, was established from a human metastatic melanoma. This cell line contains small cells, dendritic cells, and megacells with multiple nuclei. IIB‐MEL‐J expresses S 100, cytokeratin intermediate filaments and the gangliosides GD2 and GD3. It requires growth factors (insulin, EGF, and transferrin) and antioxidants for optimal growth. When plated under optimal conditions, IIB‐MEL‐J grows with a doubling time of 70–80 hours. The cells may be fractionated by Percoll gradient centrifugation into several subpopulations (A, B, and C) with different characteristics. Subpopulation A is the slowest growing, and most of the DNA‐synthesizing cells are concentrated in fractions B and C. Every subpopulation expresses S 100 and cytokeratin intermediate filaments, whereas only subpopulations B and C express GD2 and GD3. Pigmented cells are concentrated mainly in subpopulation C. Cytogenetic analysis of IIB‐MEL‐J revealed extensive chromosomal alterations, including a highly heterogeneous chromosome number and chromosomal rearrangements, gains, losses, isochromosomes, and double minutes. This highly heterogeneous cell line may be helpful to study cellular differentiation and interaction between different subpopulations in human melanoma.
Non‐selective Action of 4‐Hydroxyanisole on Melanoma Cells In Vivo
Authors: SCHWABE KONRAD , FICHTNER IDUNA , TSCHIERSCH BRUNO
Published: July 2006

In order to clarify the role of tyrosinase (E.C. 1.14.18.1) in the cytotoxicity of 4‐hydroxyanisole (4HA) in vivo, we have compared the therapeutic effects of 4HA on the B16 melanoma and Harding‐Passey melanoma, which differ significantly in their tyrosinase content. The observed therapeutic effects are moderate and similar in both tumors. Therefore, there is no evidence for an increase of the cytotoxic effect of 4HA by tyrosinase in vivo. Application of 4HA to mice carrying B16 melanoma and Harding‐Passey melanoma results in an inhibition of [3H]‐TdR incorporation into melanoma DNA as well as into DNA of liver, intestine, kidney, and spleen. There is no selective activity on melanoma cells by 4HA in vivo. Therefore, in the therapy of human melanoma by 4HA, side effects on normal tissues cannot be excluded.
Profiles of Human Melanoma Cell Surface Proteins: Effects of Culturing on Two Different Substrates
Authors: SEFTOR RICHARD E.B. , SEFTOR ELISABETH A. , CRESS ANNE E. , HENDRIX MARY J.C.
Published: July 2006

Three human melanoma cell lines of differing invasive and metastatic potentials were cultured on either a plastic surface or a denuded amniotic basement membrane, and alterations in their cell surface proteins, invasive profiles, and the presence or absence of the 69 Kd high‐affinity metastasis‐associated laminin receptor were examined. Our data indicate that the labeled, precipitatable cell surface proteins are different from the three cell lines when they are cultured on the same substrate, and change when the cells are cultured on a different substrate. Furthermore, the invasive potential (as measured in the in vitro Membrane Invasion Culture System) is decreased for all of the cell lines after culturing the cells on a basement membrane matrix compared to a plastic surface. Finally, we show that the 69 Kd high‐affinity metastasis‐associated laminin receptor can be isolated from all three cell lines cultured on the two different substrates by labeling the cell surface with trinitrobenzene sulfonic acid and immunoprecipitating these targeted proteins.
Distribution of Extracutaneous Melanin Pigment in Sparus auratus, Mugil cephalus, and Dicertranchus labrax (Pisces, Teleostei)
Authors: ZUASTI ADELINA , FERRER CONCEPCION , AROCA PILAR , SOLANO FRANCISCO
Published: July 2006

The morphological and biochemical characteristics of pigment accumulations found in the kidney, liver, spleen, and mesentery of three different species of teleost fishes have been studied. There are significant differences in number, distribution, and morphology of pigment accumulations in different organs of the three species. Biochemical studies have shown the existence of tyrosinase activity in the mesentery of Mugil cephalus and in the kidney and mesentery of Sparus auratus. No tyrosinase activity was found in any internal organs of Dicertranchus labrax. That activity was assayed using three methods: tyrosine hidroxylation, dopa oxidation, and melanin formation. The morphological and biochemical observations are in agreement. In those organs in which we have demonstrated melanin synthetic activity, the pigment cells are morphologically and like melanophores, while in the organs that show no melanin synthetic activity, the pigment cells resemble macrophages.
Effect of Interferon‐Gamma on the Expression of HLA‐DR by Human Melanoma Cells of Varying Metastatic Potential
Authors: HENDRIX MARY J.C. , SEFTOR ELISABETH A. , ECKES MICHELLE D. , WINTERS ADRIAN L. , LEONG STANLEY P.L. , SCUDERI PHILLIP
Published: July 2006

Three human melanoma cell lines of varying invasive and metastatic potential were analyzed for their ability to express HLA‐DR antigens on the cell surface as well as transcriptionally at the mRNA level in the presence and absence of IFN‐γ treatment. Cells of low and intermediate metastatic and invasive potential showed a high percentage of HLA‐DR surface expression, both before (91.2‐99.9%) and after (97.8‐99.9%) IFN‐γ treatment, as quantitated by flow cytometry. In contrast, cells of high metastatic and invasive potential expressed barely detectable levels of HLA‐DR‐positive cells before IFN‐γ treatment (0.3‐0.6%) and displayed elevated levels following treatment (42.3‐89.4%(. Allowing the highly metastatic cells to recover for 7 or 14 days following IFN‐γ treatment resulted in barely detectable levels of HLA‐DR‐positive cells. Northern blot analyses of HLA‐DR transcription levels showed a strong expression in cells of low and intermediate metastatic and invasive potential. HLA‐DR mRNA levels were not detectable in control cells of high metastatic potential nor in those cells which had undergone 7‐ and 14‐day recovery periods following IFN‐γ treatment. There was, however, an induction of HLA‐DR expression in the cells that had been treated with IFN‐γ for 72 hr and allowed no recovery period. In addition, a punctate, receptor‐like pattern of immunofluorescence staining pattern for cell surface HLA‐DR was seen after a 72 hr IFN‐γ treatment in the highly metastatic cells. In contrast, cells of low and intermediate metastatic potential expressed a homogeneous ring‐like pattern of antigen expression.
Fast Atom Bombardment Mass Spectrometry in the Study of Dopamine Melanogenesis Intermediates
Authors: ALLEGRI GRAZIELLA , ARBAN ROBERTO , COSTA CARLO , BIASIOLO MONICA , CURCURUTO ORNELLA , POZZAN ALFONSO , TRALDI PIETRO
Published: July 2006

Fast atom bombardment was applied to the study of the intermediates of the reaction dopamine‐tyrosinase after treatment with diazomethane. The identification of trimeth‐oxyindoline, dopamine‐o‐quinone and dimethoxyindole was easily achieved by this ionization method, together with accurate mass measurements and collision experiments. The structures of these compounds are in agreement with those already hypothesized in studies on melanogenesis.