bluuebunny/crossref_metadata_2025 huggingface dataset:
Establishment of a cell line with phenotypes of chondrocyte from a human osteogenic sarcoma of the mandible
Authors: Yagami Kimitoshi , Kakuta Saburo , Tachibana Hideharu , Kimura Yoshitaka , Nagumo Masao
Published: March 2003

Abstract: We have succeeded in transplanting a human osteogenic sarcoma of the mandible into athymic mice. The transplanted tumor showed marked chondrogenesis and mineralization. Recently, a cell line (USAC) with phenotypes of chondrocyte has been established from the transplanted tumor. USAC cells were stellate or spindle‐shaped in sparse culture, but polygonal or spherical at sub‐confluency to confluency. In long‐term culture, the cells were condensed and calcified nodules were formed. Production of types I, II and X collagen were detected by immunohistochemical staining and Western blot analysis. Type I collagen was strongly expressed in the stellate or spindle‐shaped cells. Although type II collagen was usually present in all cells during culture, it was strongly stained in polygonal cells at confluency. Type X collagen was seen in large polygonal cells around calcified nodules. Marked [35S]‐sulfate uptake and metachromasia were seen at the confluent stage and in the nodule. The cells around the nodules were positive for alkaline phosphatase, and the center of the nodules was stained with alizarin red. The potentiality of cartilage formation was confirmed by in vivo experiments using a diffusion chamber in athymic mice. These observations indicate that USAC cells maintain characteristics of chondrocyte progenitor cells and thus may serve as a useful model to study the sequential events of chondrogenesis and the process of morbid endochondral calcification. This experiment also demonstrated that transplantation of tumor tissue into athymic mice is a convenient strategy for establishment of a cell line.
Vascular remodelling in chronic inflammatory periodontal disease
Authors: Chapple Cheryl C. , Kumar Rakesh K. , Hunter Neil
Published: March 2003

Abstract: Periodontitis is a chronic inflammatory disease of the highly vascularised supporting tissues of the teeth. Little is known about the vascular changes in untreated advanced periodontitis. Using confocal immunofluorescence microscopy and morphometry, we defined and quantified vascular remodelling in this lesion. In the connective tissue subjacent to the altered epithelium lining of the periodontal pocket, there was a significant increase in the numerical density of vascular profiles, primarily accounted for by vessels ≥25 μm in diameter. In addition, vascular basement membranes were thickened and there was accumulation of non‐vascular basement membrane remnants. We investigated the distribution of major angiogenic growth factors in periodontitis using immunohistochemistry. Basic fibroblast growth factor, although consistently associated with blood vessels, showed no regional variation in its distribution. In contrast, there was a marked regional variation in the intensity of immunostaining for vascular endothelial growth factor, with significantly reduced staining of the pocket epithelium. The changes in the vascularity of the periodontal connective tissues in untreated advanced periodontitis may be, in part, a consequence of altered expression of angiogenic activity by the epithelium. In turn, this may reflect the epithelial response to microbial flora in the microenvironment of the periodontal pocket.
Detection of Helicobacter pylori DNA in recurrent aphthous stomatitis tissue by PCR
Authors: Riggio Marcello P. , Lennon Alan , Wray David
Published: March 2003

Abstract: Helicobacter pylori is recognised as being an aetiological agent of chronic active gastritis and peptic ulcer disease and has been associated with an increased risk of gastric cancer. The natural reservoir for H. pylori is unknown, although the oral cavity has been the focus of much attention in this respect. Given the histological similarities between gastric and oral ulceration, it seemed prudent to investigate a possible association between H. pylori and recurrent aphthous stomatitis (RAS). In this study, the potential involvement of H. pylori in the aetiology of RAS was investigated using the polymerase chain reaction (PCR). Biopsies from 28 RAS patients were analysed, in addition to 20 oral lichen planus (OLP) and 13 normal biopsies that were used as controls. Genomic DNA was extracted from biopsies, and confirmation of successful extraction of PCR‐amplifiable DNA was achieved by carrying out PCR on each DNA sample with nested primers specific for the human β‐haemoglobin gene. PCR identification of H. pylori was carried out using a primer pair specific for the H. pylori 16S ribosomal RNA (rRNA) gene. Two rounds of PCR were carried out to amplify a 295‐bp product, and the identity of amplified products was confirmed by DNA sequencing. H. pylori DNA was detected in 3 of 28 (11%) RAS samples but not in any of 20 OLP and 13 normal samples. These results do not support a definitive aetiological role for H. pylori in RAS, although the possibility that H. pylori may be involved in a small proportion of RAS cases cannot be excluded.
Post‐antifungal effect of polyene, azole and DNA‐analogue agents against oral Candida albicans and Candida tropicalis isolates in HIV disease
Authors: Anil S. , Ellepola A. N. B. , Samaranayake L. P.
Published: March 2003

Abstract: Oropharyngeal candidiasis (OPC) is the most frequent AIDS‐associated opportunistic infection, as up to 90% of HIV‐infected individuals suffer at least one episode during the course of their disease. Various in vivo and in vitro procedures have been used to assess the effectiveness of antifungal agents used in HIV infection. In the present study, we evaluated in vitro the minimum inhibitory concentration (MIC) and the post‐antifungal effect (PAFE) of two polyenes, two azoles and one DNA‐analogue against 10 oral isolates of Candida albicans and 10 of Candida tropicalis, all from HIV‐infected individuals, in order to obtain basic data on the pharmacodynamics of these drugs. One‐hour exposure to twice the MIC of all the drugs, except fluconazole, elicited a consistently high PAFE in both Candida species. Furthermore, the PAFE elicited by the antifungals (except fluconazole) was significantly prolonged for C. tropicalis compared with C. albicans. This speedy recovery of C. albicans isolates exposed to transient low concentrations of antifungals appeared to reflect its virulence compared with lesser potent species, such as C. tropicalis. Taken together, the current data, while confirming the existence of PAFE in a non‐albicans species of Candida, also provide further clues for the recalcitrance of C. albicans species in the face of antifungal therapy for oropharyngeal candidiasis.
Frequency and predictive value of the clinical manifestations in Sjögren’s syndrome
Authors: Al‐Hashimi Ibtisam , Khuder Sadik , Haghighat Nasser , Zipp Michele
Published: March 2003

Abstract: The purpose of this study was to examine the frequency and predictive value of glandular and extraglandular manifestations in Sjögren’s syndrome (SS). The clinical profiles of 169 SS patients were compared to those of 44 non‐SS controls. The specific symptoms examined were oral, ocular, vaginal, gastric, pulmonary, skin, joint and muscle pain. Statistical analyses were performed on both individual and grouped symptoms. Chi‐squared analyses showed that the frequency of all symptoms was significantly higher among patients than controls. Stepwise discriminant analysis of individual symptoms suggests that the combined symptoms of dry mouth, sore mouth, and dry eyes correctly classified 93% of SS and 97.7% of the controls. While grouped gastric, muscle, psychological, vaginal, skin, nasal, and thyroid symptoms correctly classified 64.3% of SS and 86.1% of the controls. This is the first study to examine the diagnostic value of multi‐system manifestation in SS. The overall results suggest that a comprehensive questionnaire of various symptoms may assist the diagnosis of SS. The high predictive value of the combined symptoms confirms their value in the evaluation of SS.
Immunohistochemical localization of members of the transforming growth factor (TGF)‐β superfamily in normal human salivary glands and pleomorphic adenomas
Authors: Kusafuka Kimihide , Yamaguchi Akira , Kayano Teruo , Takemura Tamiko
Published: March 2003

Abstract: Although pleomorphic adenoma is the most common type of salivary gland epithelial tumor, it frequently contains “mesenchymal”‐like components, including myxoid or chondroid tissues. We reported previously that chondroid tissue formation in pleomorphic adenoma was associated with overexpression of bone morphogenetic proteins (BMPs) by neoplastic myoepithelial cells. BMPs belong to the transforming growth factor (TGF)‐β superfamily, so we hypothesized that pleomorphic adenoma may express TGF‐βs and that these molecules may regulate mesenchymal‐like tissue formation. To evaluate this hypothesis, we immunohistochemically examined TGF‐β1, ‐β2 and ‐β3 expression and localization in normal salivary glands and in 43 cases of pleomorphic adenomas. There was no evidence of TGF‐β1 expression in normal salivary glands or pleomorphic adenomas. Signals for TGF‐β2 in the normal salivary glands were observed in the intercalated ducts, while in pleomorphic adenomas they were observed in the inner ductal cells of the tubulo‐glandular structures. Signals for TGF‐β3 in the normal salivary glands were observed in mucous cells, whereas in pleomorphic adenomas they were observed in the solid nests of neoplastic myoepithelial cells, in the portion showing squamous metaplasia, and in the inner ductal cells of tubulo‐glandular structures. TGF‐βs induce ectopic cartilage formation in vivo, but chondroid tissues in pleomorphic adenomas showed only weak TGF‐β3 expression. TGF‐β may be related to differentiation of the inner ductal cells and the neoplastic myoepithelial cells. In conclusion, pleomorphic adenomas expressed TGF‐β2 and ‐β3, which may be associated with differentiation of the inner ductal cells and neoplastic myoepithelial cells.
Precancerous foci in pleomorphic adenoma of the salivary gland: recognition of focal carcinoma and atypical tumor cells by P53 immunohistochemistry
Authors: Ohtaké Sachiko , Cheng Jun , Ida Hiroko , Suzuki Makoto , Ohshiro Kazufumi , Zhang Weiguo , Saku Takashi
Published: March 2003

Background:  It is still controversial if atypical tumor cells scattered in salivary pleomorphic adenomas are precancerous and how carcinoma arises in pleomorphic adenomas.

Methods:  We studied clinicopathologically the frequency and variation of cellular atypia among tumor cells and examined the expression status of p53 gene products as well as proliferating cell nuclear antigen (PCNA) in 101 surgical materials of pleomorphic adenomas.

Results:  Histopathologically, atypical tumor cells were found in 51% of the cases examined. Their mode of distribution was classified into three groups: focal (six cases, 6%) which could be identified as focal carcinoma, measuring less than 1 mm in diameter; sporadic (15 cases, 15%) and singular (30 cases, 30%). These atypical cells were located mainly within sheet‐like nests of tumor cells but not in chondroid or fibro‐hyaline foci. Immunohistochemically, most of the atypical cells were positive for p53 gene products and PCNA.

Conclusion:  The results indicated that atypical cells with p53 protein accumulation in their nuclei could be regarded as cells in a precancerous state not yet forming an apparent carcinomatous nest. Some cell population with these atypical cells are likely to form focal carcinomas and then to an apparent form of carcinoma in pleomorphic adenoma.
Oral lichen planus: immunohistology of mucosal lesions
Authors: Dorrego Mariana Villarroel , Correnti María , Delgado Rafael , Tapia Felix J.
Published: March 2003

Background:  Current evidence suggests that immunological mechanisms are involved in oral lichen planus (OLP) pathogenesis. The events implicate activated epithelia that comprise antigen‐presenting Langerhans cells, immunocompetent keratinocytes and subepithelial inflammatory infiltrate. Also, the presence of a high density of leucocyte cells may occur for the expression of a variety of adhesion molecules. The aim of this study was to analyse the immunoexpression of some adhesion molecules as well as lymphocytic markers in order to determine the disease pathogenesis in a Venezuelan population.

Methods:  The 18 OLP and 10 normal oral mucosa biopsies were immunostained for CD4, CD8, CD1a, LFA‐1, VCAM‐1 and ICAM‐1.

Results:  The results showed an increased number of CD4+, CD8+, CD1a+ cells in OLP. Serial sections showed CD4+ and CD8+ cells also expressed LFA‐1. The expression of ICAM‐1 and VCAM‐1 were significantly higher in OLP.

Conclusions:  The immunological reaction begins with Langerhans cells activation, which presents an antigen to CD4+ lymphocytes. Those cells through ICAM‐1 and LFA‐1 promote epithelial destruction. Afterwards, cytokine production, ICAM‐1 and VCAM‐1 expression can activate CD8+ lymphocytes leading to the chronic form of the disease.
Serum interleukin‐6 level is a useful marker in evaluating therapeutic effects of levamisole and Chinese medicinal herbs on patients with oral lichen planus
Authors: Sun Andy , Chia Jean‐San , Chang Yu‐Fong , Chiang Chun‐Pin
Published: March 2003

Background: Oral lichen planus (OLP) is a T cell‐mediated inflammatory disease. Interleukin‐6 (IL‐6) is a pro‐inflammatory cytokine that has effects on cellular and humoral immunities. Previous studies have shown that keratinocytes and tissue‐infiltrating mononuclear cells from OLP lesions can secrete IL‐6. In some OLP patients, the high serum IL‐6 levels are reduced after treatment, suggesting that IL‐6 may be a useful marker in evaluating therapeutic effects and in monitoring the disease status of OLP.

Methods: In this study, we used a solid phase, two‐site sequential chemiluminescent immunometric assay to determine the baseline serum levels of IL‐6 in a group of 180 patients with erosive OLP (EOLP), nonerosive OLP (NEOLP), erythema multiforme (EM), traumatic ulcers (TU), oral submucous fibrosis (OSF), pemphigus vulgaris (PV), or Sjögren's syndrome (SS), and in 77 normal control subjects. Some OLP patients were treated with levamisole plus Chinese medicinal herbs or levamisole only for 0.5–5.5 months and their serum IL‐6 levels were measured after treatment.

Results: We found that approximately 99% of the normal control subjects and the patients with EM, TU, or OSF had a normal serum IL‐6 level less than 5.0 pg/ml. However, 15% (22/149) OLP patients, 15% (20/136) EOLP patients, 20% (5/25) major type EOLP patients, 14% (15/111) minor type EOLP patients, 15% (2/13) NEOLP patients, 14% (1/7) EM patients, 43% (3/7) PV patients, and 100% (6/6) SS patients had a serum IL‐6 level greater than 5.0 pg/ml. The mean serum IL‐6 level in patients with OLP (3.4 ± 3.1 pg/ml, P < 0.001), EOLP (3.4 ± 3.2 pg/ml, P < 0.001), major type EOLP (4.9 ± 3.5 pg/ml, P < 0.001), minor type EOLP (3.0 ± 3.0 pg/ml, P < 0.01), or NEOLP (4.2 ± 1.5 pg/ml, P < 0.001) was significantly higher than that in normal control subjects (2.0 ± 1.5 pg/ml). A significant difference in the mean serum IL‐6 level was also found between major type and minor type EOLP patients (P < 0.01). The mean reduction of serum IL‐6 level in OLP patients treated with levamisole plus Chinese medicinal herbs was significantly higher (7.4 ± 4.7 pg/ml) than that in OLP patients treated with levamisole only (3.8 ± 2.3 pg/ml, P < 0.05), suggesting that the combination therapy was superior to levamisole only.

Conclusion: We conclude that levamisole and levamisole plus Chinese medicinal herbs can modulate the serum IL‐6 level in OLP patients. IL‐6 may be a useful marker in evaluating therapeutic effects and in monitoring the disease status of OLP.
The incidence of oropharyngeal cancer in Taiwan: an endemic betel quid chewing area
Authors: Ho Pei‐Shian , Ko Ying‐Chin , Yang Yi‐Hsin Connie , Shieh Tien‐Yu , Tsai Chih‐Cheng
Published: March 2003

Background:  Orapharyngeal cancer is the one of the most common cancers in the world. The purpose of this study was to examine the trends in oropharyngeal cancer from 1979 to 1996 in Taiwan.

Methods:  Traditional cohort analysis was employed to show the birth‐cohort effect of oropharyngeal cancer incidence. Age‐period‐cohort model analysis was used to examine the age, period and cohort effect between intraoral and pharyngeal cancer.

Result:  A significant increasing trend in oropharyngeal cancer has been seen in males. The principal increases have been seen in tongue and mouth in males, and tongue in females. In males, an increasing trend was found in successive cohorts born after 1929. The increase in incidence of intraoral cancer of males was greater than the increase in incidence of pharyngeal cancer in the younger age group, more recent time periods and the younger cohorts.

Conclusion:  The increasing incidence in oropharyngeal cancer in Taiwan is probably heavily influenced by the rising consumption of alcohol and use of betel quid. The effect of these etiologies on intraoral cancer was more significant in recent time periods, later cohorts and the younger group.
Revision of the 1992‐edition of the WHO histological typing of odontogenic tumours. A suggestion
Authors: Philipsen Hans P. , Reichart Peter A.
Published: March 2003

Classification of odontogenic tumours is an academic excercise that has developed over the last 150 years. It was not until 1971 when a 5‐year collaborated effort, organized by the World Health Organization (WHO), resulted in the first consensus on taxonomy of odontogenic tumours. The appearance of this first authoritative guide to the classification of odontogenic tumours marked the start of an era of quite intensive interest for studying this particular field of oral pathology. An updated 2nd edition of the WHO classification was published in 1992.
Milieuschilderungen zweier verrückter Monologisten.  Philip Roths Portnoy's Complaint als ein Vorbild für Thomas Brussigs Helden wie wir
Authors: Gebauer Mirjam
Published: March 2003

Untersuchungen zum Publikumserfolg Helden wie wir (1995) von Thomas Brussig betonten bisher die »Neuheit« der im Text praktizierten Erzählweise. In der vorliegenden Untersuchung hingegen wird die These vertreten, daß wesentliche thematische und stilistische Elemente der Helden präfiguriert sind. Die vergleichende Analyse des Textes mit Philip Roths Portnoy's Complaint (1969) erbringt zahlreiche Parallelen, aber auch aufschlußreiche Abweichungen in Bezug auf Roths Text. Es wird deutlich, daß Brussig mithilfe der Übernahme wesentlicher Erzählmomente, wie beispielsweise einer dominant gestalteten Sexualität, in der Nachfolge von Roths »Skandalbuch« eine erneute Provokation zustande bringt. Daß die Provokation trotz der Anlehnung an eine Textvorlage gelingt und als »neuartig« empfunden wird, deutet darauf hin, daß hier nicht von Epigonentum gesprochen werden kann, sondern vielmehr von einer geschickt arrangierten Transformation des Vorbildes mit Blick auf die Erfordernisse des veränderten kulturellen Kontextes.
L'éducation de la Marquise: Un contre‐exemple? A propos des Liaisons dangereuses
Authors: Nøjgaard Morten
Published: March 2003

Dans la fameuse lettre 81, la marquise de Merteuil, protagoniste des Liaisons dangereuses, expose ses principes «pédagogiques», véritable programme féministe.

En plus de son roman, Choderlos de Laclos a laissé trois petits écrits sur l'éducation des femmes. Il y apparaît à la fois comme l'ardent défenseur des thèses les plus hardies de Rousseau sur la femme à l'état de nature, et comme le représentant de la nouvelle idéologie bourgeoise basant la vie sociale sur la constituion hiérarchique de la famille et sur les liens de tendre affection qui en constituent l'essence spirituelle. Ces textes nous donneront l'occasion d'esquisser les idées prémodernes des femmes de la Révolution et d'en retracer le triste sort au début du dix‐neuvième siècle.
Le caractère individuel, une notion transversale chez Rousseau
Authors: Lébre Jérôme
Published: March 2003

Le caractère est une marque distinctive, qui ne devient cependant réelle et visible que dans un acte (la caractérisation). Cet article se propose d'étudier le rôle de ce dynamisme chez Rousseau. Le dualisme entre l'âme et le corps exige que le corps se caractérise en s'exerçant, que l'âme se caractérise en s'instruisant, mais aussi que l'âme, par son activitépropre, se différencie du corps et s'affirme comme esprit. L'activité spirituelle, verra‐t‐on ensuite, consiste justement à dégager et déterminer des caractères (sensibles, génériques et individuels). Le caractère individuel apparaîtra alors comme le point d'articulation entre la force naturelle du corps et la forme sociale de l'âme. Son développement expliquera les exigences fondamentales de l'éducation, qui s'élève au‐dessus de l'exercice et de l'instruction.On saisira alors mieux pourquoi l'homme naturel est sans caractère et pourquoi l'homme social a toujours, fondamentalement, bon caractère; comment naissent les grands caractères et les caractères affreux; et pourquoi Rousseau critique la philosophie, cette caractérologie dominée par l'intérêt social, au profit d'une démarche d'observation qui porte sur des individus en plein changement: art premier de l'éducateur comme du législateur, l'observation des caractères permet de saisir l'amour et la sociétéà la naissance, c'est‐à‐dire au moment ou les âmes conviennent entre elles.
Domesticating Nietzsche: Toward a Genealogy of Elisabeth Förster‐Nietzsche's ‘Novellen‐Eierchen’
Authors: Bauer Karin
Published: March 2003

This investigation of an untitled novella manuscript penned by Elisabeth Förster‐Nietzsche aims to contextualize her writing as an attempt to domesticate Nietzsche and his philosophy. It is argued that the manuscript provides unique insights into Elisabeth Förster‐Nietzsche's incestuous fantasies and conflicted stance toward marriage and motherhood. While explicitly promoting marriage and motherhood, the plot, paradoxically, depicts not a single positive, functioning marriage. Although it romanticizes marriages, the novella challenges the dominant construction of the alte Jungfer as a social, cultural, and sexual deviant and an economic burden to family and society. Thus, while the ideological pronouncements of the novella advocate marriage and motherhood, the novella subverts these pronouncements and develops alternative familial arrangements, such as marriage‐like brother–sister relations and surrogate parenthood. However, the conservative banality of these alternative models indicates that the novella is motivated more by wishfulfillment in the realm of fantasy than by the desire to develop an emancipatory dimension. Ultimately, Förster‐Nietzsche's novella confirms not only her lack of literary talent, but also the vast gap separating Förster‐Nietzsche's petit‐bourgeois consciousness from Nietzsche's yearning for the intellectual risk of the ever‐elusive free spirits.
Tyrosinase‐Mediated Formation of a Reactive Quinone from the Depigmenting Agents, 4‐tert‐Butylphenol and 4‐tert‐Butylcatechol
Authors: Thörneby‐Andersson Kirsten , Sterner Olov , Hansson Christer
Published: March 2003

Exposure of the skin to certain phenols or catechols such as 4‐tert‐butylphenol (TBP) and 4‐tert‐butylcatechol (TBC) may cause leukoderma. These substances are used in the polymer industry and numerous cases have been reported. Several theories of the mechanism for chemical leukoderma have been suggested. In the present study, TBP and TBC are shown to be oxidised by tyrosinase. The oxidation of TBC yields a quinone that is further investigated on its reactions with cysteine or glutathione (GSH). The products formed are isolated and identified by mass spectrometry and nuclear magnetic resonance as being 4‐tert‐butyl‐6‐S‐cysteinylcatechol (cys‐TBC) and 4‐tert‐butyl‐6‐S‐glutathionylcatechol (GS‐TBC). The reactive quinone is a strongly electrophilic substance that rapidly reacts with GSH. A depletion of the GSH defence system may give conditions where the quinone lives long enough to effect its toxic properties. The influence of the reactive tert‐butylquinone on enzymatic activities is demonstrated by the inhibition of glyceraldehyde‐3‐phosphate dehydrogenase.
The Study of Cutaneous Melanomas in Camargue‐Type Gray‐Skinned Horses (1): Clinical–Pathological Characterization
Authors: Fleury Catherine , Bérard Frederic , Balme Brigitte , Thomas Luc
Published: March 2003

The clinical and pathological characteristics of cutaneous melanomas occurring in Camargue‐type gray‐skinned horses are reported. Examination of 83 tumor‐bearing horses revealed that the tumors occurred most frequently underneath the tail (93.9%) and at high rates in the peri‐anal region (43.0%), the lips (33.0%), and the eyelids (24.0%), but rarely in the vulva (3.8%). Tumorous lesions were characterized by the presence of either hemispheric nodules or large infiltrated plaques, or their combinations. Microscopic examination indicated that tumorous lesions were composed mostly of melanocytes and numerous melanophages and that component cells manifested a remarkable cellular atypia with anisocytosis and anisokarinosis. Pathological examination of lesions corresponding to earlier stages of the tumors disclosed that tumor formation and its related melanogenesis occurred in close topographical association with apocrine sweat glands, but not at the dermal–epidermal junction. Larger nodules of the tumors were often composed of a concentric deposition of cell layers, each being separated by dermal components from the epidermis. Because of the absence of their tropism toward the epidermis and their multiloculation, horse melanomas are considered to be different in their pathological characteristics from human melanomas.
Structural Differences in Unbleached and Mildly‐Bleached Synthetic Tyrosine‐Derived Melanins Identified by Scanning Probe Microscopies
Authors: GALLAS JAMES M. , ZAJAC GERRY W. , SARNA TADEUSZ , STOTTER PHILIP L.
Published: March 2003

Using scanning tunneling microscopy (STM), we have imaged two types of mildly‐bleached, synthetic tyrosine‐derived melanins for comparison with the unbleached melanin from which they were prepared. These mildly‐bleached melanins were generated by mild oxidation of the unbleached melanin, using either basic hydrogen peroxide or air/light. The unbleached melanin, and two mildly‐bleached melanins, were independently deposited from very dilute tetrahydrofuran (THF) solutions onto highly oriented pyrolytic graphite (HOPG) substrate for STM imaging. Lateral dimensions (23 Å, average of two directions) of structures from each of the three samples showed no differences. However, structures from both mildly‐bleached melanins showed similar dramatic decreases (from ∼15 Å to ∼5 Å) in their STM‐measured apparent heights, compared with structures from the unbleached melanin sample. These STM observations are compatible with structural models for unbleached and mildly‐bleached melanins, incorporating a three‐dimensional structure for unbleached melanin composed of multi‐layered, Π–Π‐stacked, carboxylic and amino variants of polyaromatic polymeric sheets. The STM‐observed decrease in apparent heights after mild oxidation, which we associate with a change in stack height, has been confirmed by experiments using tapping mode atomic force microscopy (TM‐AFM) for the unbleached and mildly‐hydrogen‐peroxide‐bleached melanins (from ∼14 Å to ∼6 Å). In these TM‐AFM experiments, the melanins were deposited directly onto magnesium cation‐treated glass substrates in contact with methanolic solutions of each of the melanins. We interpret our mild‐bleaching results as an oxidative conversion of the multi‐layered, stacked sheets of mainly carboxylic and amino variants of polyquinhydrone‐like moieties, to largely de‐stacked, mildly‐bleached melanin sheets. These oxidized and, hence, electron‐deficient sheets should not readily form multi‐layered, Π–Π interacting stacks, but instead appear to be either single‐layer polyquinone sheets or, at most, double‐layer polyquinhydrone sheets. The effects of such de‐stacking on in vivo melanin photoprotection, and structural similarities between melanin derived from natural sources and the synthetic melanin samples used in this work are discussed.
Approaches to Increasing Skin Melanin with MSH Analogs and Synthetic Melanins
Authors: Pawelek John M.
Published: March 2003

Increased public awareness of ultraviolet (UV) radiation‐induced skin cancers has lead to new interest in technologies for protection from sun exposure. Although many sun protection formulations are available, few of them attempt to achieve that provided by melanin itself, i.e., wide‐spectrum absorbance of radiant energy coupled with anti‐oxidant activity from a single product. In that regard, technologies in two separate areas are at or near the commercialization stage: 1) hormonal enhancement of natural skin melanin content, and 2) inclusion of natural and synthetic melanins in cosmetic formulations to impart melanin‐like color to the skin. In this article, these approaches are briefly summarized using as examples Melanotans I and II®, superpotent analogs of the melanin‐stimulating hormone melanocortin (MSH), and Melasyn®, a group of plant‐derived synthetic melanins that have successfully been incorporated into cosmetic formulations for use as sun protectants and as cover‐ups for problems resulting from uneven pigmentation, such as seen in vitiligo.
Ocular Albinism Type 1: More Than Meets The Eye
Authors: Shen Bin , Samaraweera Preminda , Rosenberg Benjamin , Orlow Seth J.
Published: March 2003

Ocular albinism type 1 (OA1) is an X‐linked recessive disorder characterized by a severe reduction of visual acuity, and hypopigmentation of the retina that leads to nystagmus, strabismus, and photophobia/photodysphoria. Microscopic examination of both retinal pigment epithelium and skin melanocytes in OA1 reveals the presence of macromelanosomes, suggesting that the OA1 gene product plays a role in melanosome biogenesis. Studies of mutations identified from OA1 patients and an Oa1 knock‐out mouse model further implicate OA1 protein function in the late stage of melanosome development. Because its effects are primarily limited to the eye, OA1 represents an ideal model system to study the relationship between pigmentation and visual development. Based upon sequence homology and biochemical studies, OA1 may represent a novel intracellular G‐protein coupled receptor. Understanding the function of OA1 will contribute greatly to our understanding of melanosome biogenesis and the role of pigmentation in visual development.
l‐DOPA Produced Nitric Oxide in the Vitreous and Caused Greater Vasodilation in the Choroid and the Ciliary Body of Melanotic Rats than in those of Amelanotic Rats
Authors: Amaki Sachi Kobayashi , Oguchi Yoshihisa , Ogata Tetsuya , Suzuki Taiju , Akeo Kiyoshi , Hiramitsu Tadahisa
Published: March 2003

The nitrogen cycle initiates direct reduction of N2 to NH3 by enzymatic reactions. We hypothesize that l‐dihydroxyphenylalanine (l‐DOPA), a catecholamine, could be a source of nitric oxide (NO). In order to determine whether l‐DOPA generates NO and induces any biological change in the eye, we measured the generation of NO in vitro and in vivo, and investigated the histopathological changes caused by injection of l‐DOPA into the vitreous of rats. We also hypothesized that melanin granules may affect the generation of NO during the metabolism of l‐DOPA, since l‐DOPA is a precursor of melanin in the brain and the eye. Therefore, we compared the effects of l‐DOPA on the generation of NO between amelanotic and melanotic rats. NO was measured as diffusion currents by NO electrodes. In vitro, various concentrations of l‐DOPA (5, 29.9, 79.4, 152.7, and 249 μM) were added to the medium. The inhibition of NO generation by 2‐(4‐carboxyphenyl)‐4,4,5,5‐tetramethylimidazole‐1‐oxyl 3‐oxide (carboxy‐PTIO) was tested. In vivo, NO generation in the vitreous of rats was measured and the eyes were enucleated under anesthesia after l‐DOPA injection. The ocular tissues were subjected to histological examination. NO was produced from l‐DOPA in a dose‐dependent manner and was scavenged by carboxy‐PTIO in vitro. NO in the vitreous of melanotic rats was generated from l‐DOPA. Histological examination with hematoxylin‐eosin staining revealed vasodilation in the ciliary vessels and the choroid after l‐DOPA injection. Both effects were greater in melanotic rats than in amelanotic rats. The vasodilation may be attributable to NO as well as to superoxides, which can be regulated by the existence of melanin.
Establishment and Characterization of a Mouse Neural Crest Derived Cell Line (NCCmelan5)
Authors: Ooka Shiho , Kawa Yoko , Ito Masaru , Soma Yoshinao , Mizoguchi Masako
Published: March 2003

Stem cell factor (SCF) and endothelin 3 (EDN3) are both necessary for melanocyte development. We have established an immortal cell population of neural crest cells from C57BL/6 mice, cultivating them with SCF, EDN3 and 15% fetal calf serum without feeder cells, and have designated that line as C57NCC SE. C57NCC SE consists of a population of melanocytes in various stages of differentiation. We used a single‐cell cloning method, in which only one cell is transferred to each new culture plate, and succeeded in establishing an immortal cell line named NCCmelan5. All NCCmelan5 cells were positive for KIT (SCF receptor), HMB45 (human melanosomal antigen), tyrosinase‐related protein‐1 (TYRP1), tyrosinase‐related protein‐2 (TYRP2), tyrosinase and endothelin receptor B (EDNRB) and all could oxidize 3,4‐dihydroxyphenylalanine (DOPA) to form melanin. Measurement of their DNA content revealed that 88.6% of the cells were in the G0–G1 phase, suggesting that they retained normal DNA ploidy. Thus, NCCmelan5 cells have the characteristics of mature melanocytes except that they are immortal; these cells may prove useful to study factors that directly affect melanogenesis and melanocyte development without the influence of feeder cells. It is clear that our attempt to establish immortal cell lines from murine neural crest cells would have never been successful without the addition of SCF and EDN3, since C57NCC SE and NCCmelan5 cells require those factors to proliferate.
The Yellow Mutation in the Frog Rana rugosa: Pigment Organelle Deformities in the Three Types of Chromatophore
Authors: Ichikawa Youko , Ohtani Hiromi , Miura Ikuo
Published: March 2003

Crossing experiments revealed that a single recessive gene mutation (yellow) gives rise to the yellow phenotype of Rana rugosa in Japan. Ultrastructural observation of dermal chromatophores showed that the pigment organelles; melanosomes, pterinosomes, and reflecting platelets, all had structural deformities. This suggests that the yellow gene acts at the level of a primordial pigment organelle common to the three types of chromatophore.
1H NMR Spectroscopic Characterization of Solutions of Sepia Melanin, Sepia Melanin Free Acid and Human Hair Melanin
Authors: Katritzky Alan R. , Akhmedov Novruz G. , Denisenko Sergey N. , Denisko Olga V.
Published: March 2003

A 1H nuclear magnetic resonance study of Sepia melanin, Sepia melanin free acid (Sepia MFA) and human hair melanin was carried out in deuterium oxide solution at pH 10–11. The empirical formula of Sepia MFA was calculated and used to estimate the number of protons in the aromatic region of the Sepia MFA polymeric chain and to suggest a possible monomeric unit profile.
Evaluation of physiological tooth movements within clinically normal periodontal tissues by means of periodontal pulsation measurements
Authors: Ioi Hideki , Morishita Tadashi , Nakata Shunsuke , Nakasima Akihiko , Nanda Ram S.
Published: March 2003

The three‐dimensional physiological tooth movement synchronized with heartbeat, periodontal pulsation, has already been demonstrated by previous researchers. The purpose of this study was to estimate physiological tooth movements within clinically normal periodontal tissues, thus establishing periodontal pulsation standards. The measuring device consisted of an amorphous sensor and a small magnet, which could detect tooth displacement without coming into contact with the tooth surface. The samples consisted of the left maxillary central incisors of 23 adult subjects. Three points on the labial surface were used as reference points to measure the labial‐lingual movement range, and a point on the incisal edge was used for measuring the incisal‐apical movement range. Periodontal pulsation and electrocardiogram measurements were recorded simultaneously for six minutes. The results showed that the mean amplitude of periodontal pulsation concerning the labial‐lingual movement range was equal at the three labial points (0.59 µm) and tended to be smaller than that of the incisal‐apical movement range (0.87 µm). There were no significant differences in the mean amplitude of periodontal pulsation at any of the four reference points. Significant correlations of the amplitude of periodontal pulsation existed among the three labial points. Though most teeth pulsated uniformly to the labial direction, some teeth moved in a complex manner including rotation with an axis among the three labial points. These results suggest that the values of periodontal pulsation amplitude which were recorded employing the amorphous sensor device are reliable standards of periodontal pulsation within clinically normal periodontal tissues.
Prostaglandin E2 secretion from gingival fibroblasts treated with interleukin‐1β: effects of lipid extracts from Porphyromonas gingivalis or calculus
Authors: Nichols Frank C. , Levinbook Howard , Shnaydman Mariya , Goldschmidt Jeffrey
Published: March 2003

Complex lipids of Porphyromonas gingivalis have been identified in lipid extracts from calculus‐contaminated root surfaces and in diseased gingival tissues. However, little is known about the biological effects of these complex lipids on host cells. The purpose of this study was to evaluate the effects of P. gingivalis or calculus lipids on prostaglandin secretion from gingival fibroblasts. Lipids were extracted from paired subgingival plaque and teeth samples, and calculus‐contaminated root surfaces before and after scaling and root planing, in order to determine the relevant levels of lipid extracts for the treatment of gingival fibroblasts in culture. Primary cultures of gingival fibroblasts were exposed to lipid extracts from either P. gingivalis or calculus/teeth for a period of 7 days. Control and lipid‐treated cultures were exposed to human recombinant interleukin‐1β for 48 h and prostaglandin secretion from interleukin‐1β‐treated fibroblasts was compared with control and lipid‐treated fibroblasts without interleukin‐1β treatment. These experiments demonstrated that P. gingivalis lipids or calculus‐tooth lipids potentiate interleukin‐1β‐mediated prostaglandin secretory responses from gingival fibroblasts. Additionally, P. gingivalis or calculus‐tooth lipid extracts were readily taken up by gingival fibroblasts as measured by bacterial fatty acid recovery in lipid extracts of cultured fibroblasts. These results indicate that bacterial lipid penetration into gingival tissues in combination with a chronic inflammatory response may substantially potentiate prostaglandin secretion from gingival fibroblasts, thereby promoting tissue destructive processes associated with adult periodontitis.
Effect of aging on bone formation induced by recombinant human bone morphogenetic protein‐2 combined with fibrous collagen membranes at subperiosteal sites
Authors: Matsumoto A. , Yamaji K. , Kawanami M. , Kato H.
Published: March 2003

This study was designed to examine the effect of aging on bone formation induced by recombinant human bone morphogenetic protein‐2 (rhBMP‐2) combined with a fibrous collagen membrane (FCM). Implantation was done subperiosteally in bilateral palatal grooves in 34 male Wistar rats divided into three age groups: a 10‐week‐old group (10w group), a 30‐week‐old group (30w group) and a 70‐week‐old group (70w group). RhBMP‐2‐combined FCMs were implanted on the left palatal grooves as BMP‐implanted sites (BMP site), while rhBMP‐2 was not implanted on the right palatal grooves as control sites. The rats were sacrificed 6 weeks after implantation, and histometric evaluations were performed. New bone formation was observed in every site of each age group and the new bone was almost completely continuous with the original bone. The new bone volume (NBV) of the BMP site was significantly higher than that of the control site in each age group. The NBV of both the control and BMP sites were highest in the10w group and lowest in the 70w group. The disparity of NBV between the control and BMP sites, which indicated the response to implanted BMP excluding the effect of skeletal growth and surgical stimulation, did not significantly differ among the age groups. These results indicate that rhBMP‐2‐combined FCM has the ability to induce new bone formation continuous with original bone even in senescent rats. Furthermore, it appeared that, in the case of palatal subperiosteal implantation, the responsiveness to implanted BMP was independent of age, although the total volume of newly formed bone declined with aging.
Attachment, proliferation and differentiation of periodontal ligament cells on various guided tissue regeneration membranes
Authors: Takata Takashi , Wang Hom‐Lay , Miyauchi Mutsumi
Published: March 2003

The purpose of this study was to evaluate the biological effects of guided tissue regeneration (GTR) membrane materials, per se, on the periodontal tissue regeneration. Rat periodontal ligament (PDL)‐derived cells were used to study the attachment, proliferation and differentiation, in vitro, on various GTR membranes. Five commercially available membranes–bovine type I collagen (BioMend®; BM), bovine type I atelocollagen (Tissue Guide®; TG), polylactic acid (Epi‐Guide®; EG), co‐polymer of polylactic acid and polyglycolic acid (Resolute®; RL) and expanded polytetrafluoroethylene: e‐PTFE (Gore Tex®; GT)–were examined. A 3×3 mm section of the membrane was fixed to the bottom of a 35×10 mm style culture dish and plated with 2 ml of cell suspension at an initial density of 5×104 cells/ml in culture medium with 10% fetal bovine serum. For cell growth analysis, the specimens were fixed with 10% buffered formalin and stained with hematoxylin at 1.5 hours and 1, 3 and 5 days after cell seeding. The number of cells included in a unit area of 0.25 mm2 were counted under light microscopy. As a comparative scaffold of cell proliferation, a plastic cover for cell culture slip (Celldesk®: CD) was used. For analysis of cell differentiation, activity of alkaline phosphatase (ALP) and calcification were histochemically revealed after 2‐week cultivation. The initial number of PDL cells attached to the membrane at 1.5 hours after cell seeding was different among membranes. RL, TG and EG had the same level of attached cell numbers as that on CD, while the cell numbers on GT and BM were significantly lower than that on CD (p<0.01). The rate of cell proliferation with time also differed among the membranes examined. RL and BM demonstrated a significantly higher number of cells at 5 days than at 1.5 hours (p<0.01). TG had increased numbers of cells at 3 and 5 days after cell seeding. However, there was no statistical difference between the cell numbers at 1.5 hours and 5 days after cell seeding (p>0.1). EG had a similar number of cell attachments to that at 1.5 hours throughout the experimental period. There was almost no cell proliferation on GT. Cell clusters of ALP positive cells and foci of calcification were seen on all membranes except for GT, where a scant number of cells were seen. Results from this study implied that GTR membrane materials, per se, may influence cell proliferation and differentiation in the process of periodontal tissue regeneration.
Osteopontin in gingival crevicular fluid
Authors: Kido Jun‐ichi , Nakamura Teruo , Asahara Yoji , Sawa Takamasa , Kohri Kenjiro , Nagata Toshihiko
Published: March 2003

Osteopontin (OPN) is a major glycosylated phosphoprotein in bone matrix and is produced by several cells including osteoblasts, osteoclasts and macrophages. OPN levels increase in active sites of bone metabolism. Recently, several bone‐related proteins were identified in gingival crevicular fluid (GCF) to seek markers of alveolar bone resorption in periodontal disease. In this study, we investigated the existence of OPN in GCF and the correlation between OPN level in GCF and probing depth (PD) of sampling sites in 98 periodontitis patients and 35 healthy subjects. An immunoblotting analysis using 10% polyacrylamide gel showed that two forms of OPN with molecular masses of 54 and 66 kDa and several degraded fragments were detected in most GCF samples from diseased sites (PD ≥4 mm). In GCF samples from healthy sites (PD ≤3 mm), only one form (54 kDa) was observed, but any degraded fragments were not detected. When OPN amounts in GCF samples were determined by ELISA, a weak, but significant correlation was observed between OPN amount in GCF and PD (r=0.32, p=0.0013). These results demonstrate that OPN exists in GCF and that OPN level in GCF increases with the progression of periodontal disease.
Mechanical characterization of bovine periodontal ligament
Authors: Pini M. , Wiskott H. W. A. , Scherrer S. S. , Botsis J. , Belser U. C.
Published: March 2003

This study is part of a research program that aims to develop a constitutive three‐dimensional model of the periodontal ligament (PDL) through the identification of pertinent material parameters. As part of this program, bovine PDL was utilized to establish stress‐strain responses under tensile and compressive loading conditions. Fresh bovine molars were secured, frozen and prepared to appropriate dimensional specifications. Bar‐shaped specimens that comprised portions of dentine, PDL and bone were produced. Push‐pull tests were conducted using a specifically constructed loading machine. Full range monotonic stress‐strain diagrams were generated. The effect of a rate increase on cyclic S–E diagrams was also determined. The influence of specimen thickness was expressed in terms of modulus of elasticity, strength, uniaxial maximizer strain, and strain energy density. The overall load‐response was heavily hysteretic in compression. On the tensile side, after a steep rise, the curve tended to flatten out asymptotically. Variations in rate that spanned four orders of magnitude had no effect on reciprocal load responses. The E‐modulus was in the 4–8 MPa range, the strength of the PDL was 1–2 MPa, the maximizer strain was at 45–60% and the strain energy density ranged between 0.3 and 0.4 MPa.
Development of oxytalan fibers in the rat molar periodontal ligament
Authors: Tashiro Keiji , Sawada Takashi , Inoue Sadayuki , Yanagisawa Takaaki
Published: March 2003

Although oxytalan fibers are known to be a ubiquitous component of the periodontal ligament, little information has been available concerning their organization in the developing periodontal ligament. In the present study, growth and distribution of oxytalan fibers were examined in the developing periodontal ligament of rat molars aged 11, 14, 19, 21 and 28 days. A quantitative analysis of the fibers was made and the spatial relationship between the fibers and blood vessels was studied by means of a three‐dimensional reconstruction of serial sections. At the beginning of root formation, oxytalan fibers appeared at first as dot‐like structures around the root sheath as well as in areas very close to blood vessels. These structures were resolved in the electron microscope to be made up of 12‐nm‐wide microfibrils in the vicinity of the surface of the cells of the root sheath. In the process of development, these dot‐like structures elongated into entities with helical appearances. As the development further proceeded, longer oxytalan fibers were produced in the apico‐occlusal direction along with blood vessels. Quantitative analysis showed that an increase in oxytalan fibers coincided with an increase in the density of the vascular network in the developing periodontal ligament. Based on the results of the present study, the role of oxytalan fibers in the developing periodontal ligament may be in the maintenance of the integrity of the vascular system as previously suggested.