bluuebunny/crossref_metadata_2025_split huggingface dataset:
Melanin Standard Method: Empirical Formula 2
Authors: CHEDEKEL MILES R. , AHENE AGO B. , ZEISE LISA 
Published: July 2006

Natural melanins are composed of two distinct portions; a protein fraction and a chromophoric backbone. There is no unequivocal evidence for covalent bonding between these two fractions, and standard protocols used in protein purification have failed to separate the protein fraction from the chromophoric fraction. In order to study the chromophoric backbone, many workers have resorted to harsh isolation and purification protocols that are now known to degrade and damage the chromophoric portion. These artifactual melanin preparations are poor models for valid chemical, physical, and biological studies.We have developed a mild isolation and purification protocol for melanins that takes into consideration both the particulate nature of natural melanins and the stability characteristics of the chromophoric fraction. Mathematical factoring of the quantitative amino acid data into the elemental analysis was used to obtain the empirical formula of the chromophoric backbone of melanins. The analyses have shown that melanins from various sources have significantly different amino acid compositions and contents, molar C/N ratios, and empirical formulae. This method successfully differentiates melanins from a variety of sources, namely, human hair, Sepia officinalis, Sigma Chemical Company (cat. no. M8631), autoxidation of dopa, and from the feathers of Rhode Island Red chickens. Analytical results from these studies are presented and discussed.
Further Evidence for Involvement of Both Cell Mediated and Humoral Immunity in Generalized Vitiligo
Authors: ABDEL‐NASER M. BADAWY , KRÜGER‐KRASAGAKES S. , KRASAGAKIS K. , GOLLNICK H. , ORFANOS C.E. 
Published: July 2006

Immunohistochemical and immunoserological evidence supports the involvement of both cell‐mediated and humoral mechanisms in the pathogenesis of melanocyte destruction in vitiligo. Punch biopsies from depigmented vitiliginous skin (VS), normal‐looking pigmented skin (PS), and marginal skin (MS) from patients with generalized vitiligo (n = 15) were labeled with K 1.2.58, OKM1 (CD11b), Leu 11b (CD16), Leu 19 (CD56), IFN‐γreceptor, IL‐2 receptor (CD25), IgG, IgM, C3c, and C3d MoAbs. In addition, in vitro effects of vitiligo sera (n = 13) on human newborn melanocytes (HMel) under different culture conditions were studied.The immunohistochemical findings showed absence of K 1.2.58+ epidermal melanocytes in VS and abnormal morphology in MS. In these areas, a few CD11b + cells in the dermis and epidermis could be detected but no significant numbers of CD16+ or CD56+ cells were seen among the mononuclear cellular infiltrate. IL‐2 and IFN‐γ receptors were clearly expressed by the cellular infiltrate. No significant deposition of complement or immunoglobulin was seen.The addition of vitiligo sera to HMel cultures induced a significant cellular proliferation. The stimulation of cell proliferation occurred regardless whether the sera were added alone or when preheated (56°C for 1 hr) and then supplemented with a complement source (P < 0.01 at 2%, P < 0.001 at 10%, and P < 0.01 at 20% for sera alone) (P > 0.05 at 2%, P < 0.05 at 10%, and P < 0.01 at 20% for decomplemented sera plus complement). In contrast, incubation of vitiligo sera together with normal lymphocytes with HMel significantly decreased the number of living melanocytes in a dose dependent manner, suggesting an antibody‐dependent cellular cytotoxicity (ADCC) reaction (P < 0.01 at 2% and 10%, P < 0.001 at 20%).The presence of lymphocytic infiltrate at marginal skin with evidence for IL‐2‐ and IFN‐γ‐receptor expression and the decrease in the number of living cells by ADCC‐like mechanisms provide further support for an autoimmune pathogenesis in vitiligo.
Antioxidant Status in the Blood of Patients With Active Vitiligo
Authors: PICARDO MAURO , PASSI SIRO , MORRONE ALDO , GRANDINETTI MAURO , CARLO ALDO DI , IPPOLITO FERDINANDO 
Published: July 2006

We have previously reported that patients with active vitiligo (AVP) have elevated urinary levels of catecholamine metabolites, such as homovanillic and vanilmandelic acids, irrespective of the form of the disease (acrofacial, segmental, generalized). We have suggested that abnormal release of catecholamines from autonomic nerve endings might play an etiological role in the onset and development of vitiligo through an overproduction of toxic (oxy)radicals in the microenvironment of melanocytes in the affected areas.In the present study we have investigated whether this suggested increase in radicals might be associated with an oxidative stress in the blood of AVP. We have analyzed by gas‐chromatography mass‐spectrometry, by high pressure liquid chromatography, by spectophotometry plasma levels of vitamin E (Vit E), lipoperoxides (LIP), and polyunsaturated fatty acids of phospholipids (PL‐FA), erythrocyte reduced glutathione (GSH), glutathione peroxidase (GSH‐Px), and superoxide dismutase (SOD) activities in 62 patients affected with different forms of active vitiligo (acrofacial, segmental, generalized) and in 60 age‐matched controls. Our results show that blood levels of Vit E, SOD, GSH, GSH‐Px activity, LIP and PL‐FA in AVP were not significantly different from those of healthy age matched controls, indicating that melanocyte damage in vitiligo is not linked with a generalized oxidative stress.
New Thioureas and Related Substances Intended for Melanoma Targeting
Authors: MÅRS ULLA , LARSSON BENGT S. 
Published: July 2006

Thiouracil and a few related drugs are known to be melanoma‐seeking agents owing to specific incorporation into nascent melanin. The melanin‐affinic properties are apparently due to binding to intermediates, preferably dopaquinone, produced in the melanin synthetic pathway by tyrosinase‐catalysed oxidation of tyrosine.In the present paper, in vitro screening methods have been used for the identification of possible melanoma seekers according to the above principle. The binding of test substance to dopaquinone suppresses dopachrome formation by the withdrawal of dopaquinone from the reaction mixture, and the decrease in dopachrome concentration was monitored spectrophotometrically at 475 nm. In order to eliminate false results caused by tyrosinase inhibition, which also will decrease the dopachrome concentration, the oxygen consumption was followed potentiometrically. To avoid the effect of tyrosinase inhibition on dopachrome formation, additional experiments with autoxidation of L‐dopa in the presence of test substance were performed. Of the 22 substances (mainly thioureylenes and thioamides) studied, 4,5,6‐triamino‐2(H)‐pyrimidinehtionsulfate, trithiocyanuric acid, 2‐thiouracil, 6‐methyl‐2‐thiouracil, and 4‐amino‐2‐mercaptopyrimidine most effectively decreased the dopachrome formation with no or little inhibition of tyrosinase activity. They should therefore be regarded as potential melanoma seekers. In a complementary autoradiographic study on the uptake of the potent tyrosinase inhibitor mercaptobenzothiazole (MBT) in B 16 melanoma, transplanted to mice, it was found that strong tyrosinase inhibition seems to decrease incorporation into melanin in vivo. MBT was partly accumulated in restricted areas of the tumor, which may be explained by the small molar dose injected.
The Pinkeyed‐Dilution Protein and the Eumelanin/Pheomelanin Switch: In Support of a Unifying Hypothesis
Authors: LAMOREUX M. LYNN , ZHOU BAO‐KANG , ROSEMBLAT SUSANA , ORLOW SETH J. 
Published: July 2006

The two major types of mammalian melanin are pheomelanin (yellow or red pigment) and eumelanin (black or brown). The agouti (A) and extension (E) loci determine whether follicular melanocytes will deposit pheomelanin or eumelanin within their melanosomes. Mutations at the murine pinkeyed‐dilution (P) locus cause a striking reduction in deposition of eumelanic, but not pheomelanic, pigment. The mRNA encoded at the P locus is not expressed in skin that exclusively produces pheomelanic pigment as a result of mutation at the agouti locus.We have suggested, based upon both genetic and biochemical evidence, that three key melanogenic proteins—tyrosinase, tyrosinase‐related‐protein‐1 (TRP‐1), and TRP‐2, encoded at the albino (C), brown (B), and slaty (Slt) loci, respectively—form a high‐molecular‐weight “melanogenic complex” within the melanosome. High‐molecular‐weight forms of tyrosinase, TRP‐1 and TRP‐2, are absent from eumelanic ocular tissues of pun/pun mice that fail to produce normal P‐locus transcript, even though these mice are genetically normal at the loci that regulate production of the three melanogenic proteins. We have hypothesized that the presence of the p‐locus protein is important for the integrity of the melanogenic complex and for the levels of members of the TRP family. We show here that the yellow skins of mice mutant at the agouti or extension loci, as well as the nonyellow skins of pinkeyed‐unstable (pun/pun) mice, demonstrate greatly diminished levels of tyrosinase, TRP‐1 and TRP‐2, and an absence or markedly decreased proportion of high‐molecular‐weight forms of melanogenic proteins.We conclude that normal levels of wild‐type P‐locus protein are necessary for eumelanogenesis and that the absence of this protein may be necessary, but is not sufficient to cause the melanosome to switch to the production of pheomelanin. We discuss the implications of our results in relation to the interacting genetic controls regulating melanogenesis.
Electron Transfer and Photoprotective Properties of Melanins in Solution
Authors: MENTER JULIAN M. , WILLIS ISAAC 
Published: July 2006

The polyquinoid nature of eumelanin(s) enables them to couple oxidation of electron donors with the reduction of electron acceptors. We have studied the ability of synthetic (Sigma) and “biological” (cuttlefish sepia) melanins to mediate electron transfer between hydroxybenzene donors (tyrosine, dopa, chemical depigmenters) and model acceptors (ferricyanide, tyrosinase). 1) Depending on the reductant, melanin either retards or accelerates ferricyanide reduction. Reaction kinetics are consistent with a mechanism involving non‐interactive binding of both hydroxybenzene and ferricyanide to melanin prior to coupled electron transfer. 2) Melanins also act as an electron conduit in markedly accelerating the tyrosinase‐catalyzed oxygenation of p‐hydroxyanisole (MMEH). The active species appears to be a complex between melanin and MMEH. The magnitude of both effects depend on the type of melanin as well as its oxidation state.Sepia (eu)melanin appears to protect against UV‐induced damage to acid‐soluble collagen, as judged by irreversible loss of intrinsic collagen fluorescence. Photoprotection against this type of damage appears primarily to involve optical absorption/scattering by the pigment.
Multiple α2‐Adrenoceptor Signalling Pathways Mediate Pigment Aggregation Within Melanophores
Authors: SVENSSON SAMUEL P.S. , ADOLFSSON PER I. , GRUNDSTRÖM NILS , KARLSSON JAN OLOF G. 
Published: July 2006

It has previously been shown that α2‐adrenoceptors (α2‐ARs) mediate pigment granule (melanosome) aggregation in melanophores of the teleost fish Labrus ossifagus. The present investigation scrutinized the signalling mechanisms of melanosome aggregation induced by sympathetic nerve stimulation or by exogenous addition of α‐AR agonists and cAMP analogues. The following was observed: i) nerve‐induced melanosome aggregation was associated with a rapid decrease in the cAMP level; ii) noradrenaline or medetomidine (an α2‐AR agonist) caused melanosome aggregation and reduced the cAMP content; iii) RP‐S‐CI‐cAMP, a membrane‐permeating inhibitor of protein kinase A induced melanosome aggregation; and iv) B‐HT 920 (an α2‐AR agonist) and methoxamine (an α1‐AR agonist) induced melanosome aggregation, although they did not reduce cAMP.It has been suggested that in some teleost species α1‐ARs mediate melanosome aggregation by increasing the level of intracellular calcium. However, we found that the effect of methoxamine in melanophores from Labrus ossifagus could be blocked by yohimbine (an α2‐AR antagonist) but not by equimolar concentration of prazosin (an α1‐AR antagonist). Furthermore, 1 μM ionomycin (a calcium ionophore) did not induce melanosome aggregation. Our findings therefore do not indicate that α1‐ARs and/or an increase in intracellular calcium mediate melanosome aggregation in Labrus ossifagus.Our results suggest that α2‐AR‐mediated melanosome aggregation is induced by multiple signalling pathways. One of these involves a reduction in cAMP, but none involves an increase in intracellular calcium.
The Role of Melanocytes in the Repair of UV Related DNA Damage in Keratinocytes
Authors: IYENGAR BHANU 
Published: July 2006

Epidermal pigmentation and UV exposure are related to the incidence of skin tumors. There is a higher incidence of UV related skin tumors in populations with low pigment and in vitiligo patients, resulting from DNA damage. Normally DNA repair processes set in with the expression of PCNA in the keratinocyte.The present study was conducted on the marginal zone skin in vitiligo. Whole skin organ cultures irradiated with increasing doses of UV in the 280–400 nm range show that in the depigmented area there is no expression of PCNA by the keratinocytes. In comparison, the marginal zone keratinocytes show a dose related positivity in the presence of UV responsive melanocytes. These photoresponsive melanocytes show dendricity and cytoplasmic PCNA positivity. The melanocytes interact with keratinocytes by active melanosome transfer. From this study it is suggested that this involves transfer of PCNA as well.The present study indicates the differentiating keratinocytes in skin do not express PCNA but appear to be dependent on active UV responding melanocytes for DNA repair. This factor could play an important role in the occurrence of UV‐related skin tumors.
Identification of Microtubule‐Organizing Centers in Interphase Melanophores of Xenopus Laevis Larvae In Vivo
Authors: RUBINA KSENIYA A. , GULAK PAVEL V. , SMIRNOVA ELENA A. , STARODUBOV SERGEI M. , ONISHCHENKO GALINA E. 
Published: July 2006

The morphological characteristics of microtubule‐organizing centers (MTOCs) in dermal interphase melanophores of Xenopus laevis larvae in vivo at 51‐53 stages of development has been studied using immuno‐stained semi‐thick sections by fluorescent microscopy combined with computer image analysis. Computer image analysis of melanophores with aggregated and dispersed pigment granules, stained with the antibodies against the centrosome‐specific component (CTR210) and tubulin, has revealed the presence of one main focus of microtubule convergence in the cell body, which coincides with the localization of the centrosome‐specific antigen. An electron microscopy of those melanophores has shown that aggregation or dispersion of melanosomes is accompanied by changes in the morphological arrangement of the MTOC/centrosome. The centrosome in melanophores with dispersed pigment exhibits a conventional organization, and their melanosomes are situated in an immediate vicinity of the centrioles. In melanophores with aggregated pigment, MTOC is characterized by a three‐zonal organization: the centrosome with centrioles, the centrosphere, and an outlying radial arrangement of microtubules and their associated inclusions. The centrosome in interphase melanophores is presumed to contain a pair of centrioles or numerous centrioles.Because of an inability of detecting additional MTOCs, it has been considered that an active MTOC in interphase melanophores of X. laevis is the centrosome. We assume that remaining intact microtubules in the cytoplasmic processes of mitotic melanophores (Rubina et al., 1999) derive either from the aster or the centrosome active at the interphase.
Anatomy of a Counter-Bar Association: The Chicago Council of Lawyers
Authors: Powell Michael 
Published: July 2006

There have been few successful attempts in the history of the organized bar since 1870 to establish alternative bar groups that challenge the dominance of the large comprehensive local and state bar associations over the representation of lawyers' interests. Founded in 1969, a product of the social ferment of the 1960s, the Chicago Council of Lawyers provides an example of one such attempt. This paper examines the conditions under which a reform-oriented counter-bar association is likely to arise, the factors that permitted its successful establishment in Chicago, and the functions it serves within the legal profession as an alternative to the Chicago Bar Association.While the violence surrounding the 1968 Democratic National Convention in Chicago may have sparked the formation of an alternative bar association, it was intraprofessional matters that deeply concerned the founders of the Council particularly the performance of the organized bar in providing legal services to the poor and in improving the quality of the judiciary. Within the legal profession itself there was also a striking disjunction between the age of the leadership of the bar and of the numerous young lawyers who flooded in-to the bar in the 1960s. Preexisting networks of young activist lawyers greatly facilitated organizational formation.As a reformist group with a small and relatively homogeneous membership, and lacking strong ties to powerful institutions, the Council can afford to take strong stances on controversial issues. By aggressively supporting positions at odds with those of the more established bar associations, and thus providing the media, the public, and legislators with an alternative viewpoint, the Council contributes to shattering the myth of a unified profession and to the demystification of professional authority.
URLTA in Operation: The Oregon Experience
Authors: Brakel Samuel Jan 
Published: July 2006

Section 1.102(b) of the uniform act states the primary objectives, the “underlying purposes and policies” of this model legislation:

(1) to simplify, clarify, modernize, and revise the law governing the rental of dwelling units and the rights and obligations of landlords and tenants;
(2) to encourage landlords and tenants to maintain and improve the quality of housing; and
(3) to make uniform the law with respect to the subject of this Act among those states which enact it.
The Historical Context of Small Claims Courts
Authors: Steele Eric H. 
Published: July 2006

The conception of simple, informal, lawyerless courts where ordinary people can settle their affairs amicably without expense, delay, technicality, or contentiousness has fascinated Americans since colonial times. This theme can be seen running through the movements to codify the law, simplify legal procedure, open the practice of law to Everyman, create conciliation courts; the creation of the small claims courts and administrative tribunals; and attempts in the 1960s and 1970s to divert small matters out of the courts altogether and into Neighborhood Justice Centers and other informal dispute resolution mechanisms.The long and complex history of reform has been characterized by cyclical shifts in emphasis between two principal modes of characterizing small claims. One mode characterizes small claims as petty private quarrels and has led to attempts to supply justice by aiding fair outcomes between the particular parties. Since no broader social impact of the dispute is seen, the most efficient possible individual level response is viewed as appropriate. The other mode perceives small claims as particular instances of important systematic injustices between social groups or classes and has led to attempts to use small claims processing as the forum for making important policy. Perceiving broad social impact of the resolution of small claims, one will see a mobilization of aggregate resources to deal with them as important social problems as appropriate.As a result, entire classes of cases and issues may be skimmed off and dealt with collectively as important social-legal problems. When this occurs the perception of the small claims that remain shifts to the other mode, and they are viewed as less important residual petty quarrels meriting less attention and resources. This periodic skimming off of certain claims and waning of collective attention to the remaining mass of claims has introduced a cyclical element into the development of small claims courts (and other legal reforms). Thus the mode of preceiving small claims itself conditions the mode of legal response which is advocated.
Influence and Issues in the Legal Community: The Role of a Legal Elite
Authors: Slovak Jeffrey S. 
Published: July 2006

This article is the third and last in a series that has focused on the corporate actor elite of Chicago's legal community—those attorneys who practice law with and for the major business, social, civic, cultural, and charitable organizations in the city. In this paper, the focus is on the participation of the members of that elite in a series of issues that have arisen in both the legal community and the larger society in the recent past.The article first examines the resources for collective decision making which the members of the corporate actor legal elite bring to the process of community issue resolution. It then examines in detail elite issue preferences and the patterns of elite participation in five professional and political issues. From this analysis an interesting “paradox of power” emerges: the elite is most successful on those issues in which it is least interested and active and least successful on those which most heavily attract its participation. The article concludes with a discussion of the reason for this paradox, basing its answer in larger sociological theories of the activation of different types of resources in different types of community conflict.
Metaphor and Imagination in James Wilson's Theory of Federal Union
Authors: Conrad Stephen A. 
Published: July 2006

“Through metaphor, the past has the capacity to imagine us, and we it.” -Cynthia Ozick, in “The Moral Necessity of Metaphor”

American federalism is nothing more-und nothing less-than a metaphor.
This was how lames Wilson, the most prominent lawyer at the Philadelphia Convention, came to approach the novel problem of understanding and conveying what federalism in a modern republic should mean. The Federal Republic created in 1787 was, for Wilson, more than a mutter of ingenious political design, more than a mutter of the “new science of politics,” and more than a mutter of constitutional law or constitutionalism itself-unless the Constitution were seen to “comprehend” the moral purpose and moral promise of the new nation.
To Wilson, this view of the importance of the moral content of republican federalism was entailed by the “knowledge” that he took to be the necessary foundation of the Republic. It was this knowledge of certain fundamental principles- of “moral science,‘I human nature, and the nature of language, and, more generally, of “cultivation” us a political and social process that was also an end in itself-that ultimately justified “the People” us the “sublime” metaphor governing American constitutional theory.
Yet, for all Wilson's faith in figurative “comprehensiveness,” his distinctive approach to securing the New Republic through a federal union of the American People seems to have proved less and less compelling to his contemporaries the more he tried to pursue it as far us his vision of a politics of cultivation directed.