bluuebunny/crossref_metadata_2025 huggingface dataset:
Survival in fluctuating bank vole populations: seasonal and yearly variations
Authors: Crespin Laurent , Verhagen Ron , Stenseth Nils Chr. , Yoccoz Nigel G. , Prévot‐Julliard Anne‐Caroline , Lebreton Jean‐Dominique
Published: March 2003

For most organisms, both within‐year (i.e. seasonal) and between‐year variations in demography are important components in shaping the population dynamic patterns observed on a multiannual scale. These two sources of variation have, however, rarely been studied simultaneously. Most of the recent work on small rodent population dynamics, for example, has focused on between‐year variation. Densities of seed‐ and fruit‐eating rodents, such as the bank vole (Clethrionomys glareolus), are in particular known to have between‐year variation related to seed crop production. Here we report on the analysis of a long‐term (1976–1982) capture‐mark‐recapture (CMR) study of the bank vole in Belgium. The study was done on two grids, an open and a fenced grid. As part of the CMR statistical analysis, we propose a general modelling approach which allows for a detailed understanding of the relative importance of seasonal and between‐year variation in survival. We demonstrate that most of the seasonal variation corresponds to a lower apparent survival in spring compared to the rest of the year. During winter, apparent survival was lower on the open grid than on the fenced grid. Dispersal is therefore concluded to be an important determinant of the seasonal pattern. The between‐year variation in survival is largely attributable to variation in seed crops, and is comparable in magnitude to the seasonal variation.
Density dependence in blowfly populations: experimental evaluation of non‐parametric time‐series modelling
Authors: Moe S. Jannicke , Stenseth Nils Chr. , Smith Robert H.
Published: March 2003

Two approaches for describing density dependence in demographic rates of stage‐structured populations are compared in this study. Time‐series data from laboratory blowfly populations (Lucilia sericata) have been analysed in a separate study, with a statistical modelling approach that incorporated density dependences as unspecified (non‐parametric) functions. In this study, we assessed density‐dependent structures by manipulating densities of larvae and adults in cohorts of blowflies and measuring the demographic rates. We here compare the density‐dependent structures revealed by the cohort experiments with those estimated by the non‐parametric model. This model estimates the demographic rates to have the following density‐dependent structures: (i) larval survival was non‐linearly density‐dependent (a ‘humped’ function), (ii) adult survival was density‐independent, and (iii) reproductive rate decreased with adult density. In the cohort experiments reported here, (i) juvenile survival exhibited a positive density dependence in low densities (facilitation), which became negative at higher densities (competition). Pupal and adult size decreased with initial larval density. (ii) Adult survival was reduced by high initial larval density, but it was independent of adult density. (iii) Reproductive rate was reduced by high initial larval density, and by high adult density in populations of large individuals (from low larval density). Hence, the results from these experiments support the non‐parametric model estimates regarding density‐dependent structures of demographic rates in the blowfly populations. The mean demographic rates, however, were apparently underestimated by the model. We conclude that non‐parametric modelling is a useful first approach for exploratory analysis of ecological time‐series data.
The ecological consequences of unpalatable prey: phytoplankton response to nutrient and predator additions
Authors: Bell Thomas
Published: March 2003

Recent theoretical and laboratory studies have suggested that unpalatable prey modify the degree to which trophic levels are regulated by bottom‐up or top‐down forces such that primarily edible communities are regulated by predation and primarily unpalatable communities are regulated by resource supply. Despite the hypothesised importance of prey edibility, experiments have only rarely examined the response of primary producers to nutrient enrichment or the addition of a top trophic level following the reduction or elimination of inedible species. I performed two experiments in aquatic enclosures in which the prey (phytoplankton) had been manipulated to create treatments composed either nearly exclusively of only edible phytoplankton or with both edible and inedible phytoplankton. In the first experiment, the two types of phytoplankton community were subjected to either high or low nutrient concentrations. In the second experiment, the two types of phytoplankton community were present in enclosures with either 2 or 3 trophic levels. I found that the impact of both the nutrients and the number of trophic levels on total phytoplankton biomass was modified by the edibility of the phytoplankton community. Although enclosures with only edible phytoplankton were able to increase with enrichment, there was a greater overall phytoplankton biomass in enclosures with both edible and inedible phytoplankton. The addition of a third trophic level had a positive effect on phytoplankton biomass when only edible phytoplankton were present, but had no effect on phytoplankton biomass when both edible and inedible phytoplankton were present. These results therefore provide support for the hypothesis that the proportion of inedible phytoplankton determines the degree to which communities are regulated by top‐down or bottom‐up forces.
Interactions between root and shoot competition vary among species
Authors: Cahill, Jr. James F.
Published: March 2003

Understanding how the competition varies with productivity is essential for differentiating among alternative models of plant community organization. Prior attempts to explain shifts in root and shoot competition along gradients have generally assumed an additive interaction between the two competitive forms, using an experimental design which does not fully separate both above‐ and belowground processes. At the most basic level, few field studies have separated root and shoot competition, and we have limited knowledge about both the relative importance of these processes, and how they interact to affect plant growth in the field. Presented here are findings from a field study in which root and shoot competition were experimentally separated by using root exclusion tubes and neighbor tiebacks in an early successional community. Individuals of four species (Abutilon theophrasti, Amaranthus retroflexus, Rumex crispus, and Plantago lanceolata) were grown at two levels of fertilization with full competition, aboveground competition only, belowground competition only, or neither above‐ nor belowground competition. Competition was measured as competitive response, which is the natural log of the relative biomass of a target plant grown with competition compared to growth without competition. In contrast to predictions from current models of productivity‐competition relationships, but in agreement with other experimental studies, there was no change in the strengths or root, shoot, or total competition with a modest increase in productivity. Despite no effect of fertilization on the strength of competition, the form of interaction between root and shoot competition varied both as a function of species identity and fertilization. For both of the rosette forming species, the combined effects of root and shoot competition were less than predicted assuming no interaction (a “negative interaction”), with one species switching from a negative to an additive interaction with fertilization. The fact that fertilization caused a shift in the root‐shoot interaction, but not in the total strength of root and shoot competition, suggests that the root‐shoot interaction is itself a highly labile variable. If root‐shoot interactions are common in natural systems, then simply measuring the strength of one form of competition in no way provides any information about the overall importance of that competitive form to plant growth.
Growth of two peat‐forming mosses in subarctic mires: species interactions and effects of simulated climate change
Authors: Sonesson Mats , Carlsson Bengt Å. , Callaghan Terry V. , Halling Sven , Björn Lars Olof , Bertgren Monika , Johanson Ulf
Published: March 2003

In patches of co‐occurring species in natural plant communities, there is a finely poised balance between species in the ways in which they respond to prevailing moisture and temperature regimes. However, environmental change scenarios, in which temperature, moisture and ultraviolet‐B radiation are suggested to increase, may favour one of the species. The imbalance is likely to occur at the levels of interactions between patches of the different species and at the shoot level when neighbouring shoots belong to different species. We increased temperature and UV‐B in a two‐way factorial experiment and increased water supply independently in two subarctic mire communities dominated by the mossesSphagnum fuscumandDicranum elongatum. The effects of simulated increase in UV‐B were studied using two separate radiation systems, i.e. a “square wave” system and a “modulated” system.  When precipitation was enhanced, both species showed an increase in growth but this was not sustained beyond 5 mm per day.S. fuscumshowed a 50% greater response to enhanced precipitation than didD. elongatum, as would be expected from their habitat preferences. Under ambient temperature,S. fuscumgrew 67% faster thanD. elongatumand this relative difference in response was maintained after one year under a temperature enhancement. The response by species over the winter period was moderated by their neighbours.S. fuscumgrowth was enhanced when it grew next toD. elongatumwhereasD. elongatumgrew better with neighbours of its own species. Increased temperature and UV‐B radiation did not affect the interaction between the species.  Although a balance was maintained between the two species over the short duration of the experiment, potential was shown for an imbalance to occur over longer periods and particularly if winter warming and precipitation are greater than those in summer.  During the peak growing season 20% increased UV‐B over ambient had a negative effect onS. fuscumunder increased temperature but there were no overall seasonal effects on either species, irrespective of method of UV supplementation.
Predator‐prey shell games: large‐scale movement and its implications for decision‐making by prey
Authors: Mitchell William A. , Lima Steven L.
Published: March 2003

Many classical models of food patch use under predation risk assume that predators impose patch‐specific predation risks independent of prey behavior. These models predict that prey should leave a chosen patch only if and when the food depletes below some critical level. In nature, however, prey individuals may regularly move among food patches, even in the apparent absence of food depletion. We suggest that such prey movement is part of a predator‐prey “shell game”, in which predators attempt to learn prey location, and the prey attempt to be unpredictable in space. We investigate this shell game using an individual‐based model that allows predators to update information about prey location, and permits prey to move with some random component among patches, but with reduced energy intake. Our results show the best prey strategy depends on what the predator does. A non‐learning (randomly moving) predator favors non‐moving prey – moving prey suffer higher starvation and predation. However, a learning predator favors prey movement. In general, the best prey strategy involves movement biased toward, but not completely committed to, the richer food patch. The strategy of prey movement remains beneficial even in combination with other anti‐predator defenses, such as prey vigilance.
Aspects of cell proliferation in oral epithelial dysplastic lesions
Authors: Oliver Richard J. , MacDonald D. Gordon , Felix David H.
Published: March 2003

Abstract: There is a need for objective methods of assessment of oral epithelial precancerous lesions and reliable markers for the prediction of malignant change in these lesions. Cell proliferation was examined in 20 dysplastic lesions from the tongue and floor of mouth using bromodeoxyuridine (BrdU) and Ki‐67, and a histological compartment analysis was performed. Half of a fresh biopsy from each case was incubated in BrdU for 15 min, the other half was routinely processed and used for Ki‐67 analysis. Sections from each block were immunohistochemically stained with antibodies against BrdU and Ki‐67. Dysplasia was graded according to the method of Smith & Pindborg. The BrdU labelling index (LI) and the growth fraction (GF), assessed by the use of Ki‐67, was quantified and expressed as units per millimetre basement membrane length (BL) and per 100 total nucleated cells (TNC). The mean LI/TNC was 10.87 (SD 3.65) and the mean LI/BL was 51.55 (SD 20.75). The mean GF/TNC was 26.66 (SD 17.78) and GF/BL was 157.07 (SD 125.84). The mean epithelial thickness was 229.09 μm (SD 104.73). The LI/BL correlated with the atypia score and with the GF/BL. The progenitor compartment sizes also correlated with the atypia scores. The BrdU labelling index provides a further objective measurement of oral epithelial dysplasia and the progenitor compartments were large, implying that basal cell hyperplasia is a significant component of the dysplasia.
A simple and rapid technique for the detection of Epstein‐Barr virus DNA in HIV‐associated oral hairy leukoplakia biopsies
Authors: Mabruk M. J. E. M. F. , Antonio M. , Flint S. R. , Coleman D. C. , Toner M. , Kay E. , Leader M. , Atkins G. J.
Published: March 2003

Abstract: A method of generating nucleic acid probes by polymerase chain reaction (PCR) for the detection of Epstein–Barr virus (EBV)‐DNA by in situ hybridization in oral hairy leukoplakia (OHL) lesions is described. This method has the advantage over older methods of being cheaper, quicker and retaining sensitivity and specificity. Purified PCR products of Epstein‐Barr virus DNA of 110 bp and 328 bp were labelled with biotin by nick translation or random primer labelling and were compared in in situ hybridization experiments with probes prepared by incorporation of biotin‐labelled nucleotides in the PCR reaction mixture, with EBV viral DNA as a template. These probes were applied to 18 OHL tongue biopsies known to be positive for EBV‐DNA, using a commercially available biotin‐labelled BamHI “V” fragment EBV‐DNA probe. To determine the specificity of the probes, we applied them to 20 normal tongue tissue samples and to 12 biopsies taken from keratotic tongue lesions from patients without risk factors for HIV infection and known to be negative for EBV‐DNA. Clear positive signals for EBV‐DNA were detected in all 18 cases of OHL biopsies using the amplimer of 328 bp labelled by PCR and random primer labelling. However, nick translation labelling was less efficient and sensitive. All control specimens were negative for EBV‐DNA.
Oral submucous fibrosis patients have altered levels of cytokine production
Authors: Haque M. F. , Meghji S. , Khitab U. , Harris M.
Published: March 2003

Abstract: Oral submucous fibrosis (OSF) is a pre‐malignant fibrotic lesion of the mouth in betel quid chewers and is characterised by dense bands of collagen in the juxta‐epithelial region preceded by inflammation. We have investigated the spontaneous and stimulated production of cytokines by peripheral blood mononuclear cells (PBMC) from OSF patients and compared them with genetically‐related relatives, Indian and Caucasian control subjects. The cytokines studied included: interleukin‐1β (IL‐1β), interleukin‐6 (IL‐6), interleukin‐8 (IL‐8), tumour necrosis factor‐α (TNF‐α) and interferon‐γ (IFN‐γ). The results show: a) significant differences in the stimulated versus non‐stimulated levels of IL‐1β, IL‐6, IL‐8 and TNF‐α but not of IFN‐γ production by patients, and in the relatives’ stimulated versus non‐stimulated levels of IL‐1β, IL‐6 and IFN‐γ; b) no difference in the spontaneous cytokine production between any two groups; and c) significant increases in the patients’ stimulated cytokines compared to the Caucasian and Indian controls (P≤0.050). These results demonstrate increased levels of pro‐inflammatory cytokines and reduced anti‐fibrotic IFN‐γ in patients with OSF, which may be central to the pathogenesis of OSF.
Immunohistochemical study of bcl‐2 protein, Ki‐67 antigen and p53 protein in epithelium of glandular odontogenic cysts and dentigerous cysts
Authors: Tosios Konstantinos I. , Kakarantza‐Angelopoulou Elina , Kapranos Nikiforos
Published: March 2003

Abstract: The aim of the present study was the evaluation of the immunohistochemical expression of the apoptosis‐inhibiting protein bcl‐2, the cell‐cycle‐related antigen Ki‐67 and the p53 protein, which is involved both in cell cycle and apoptosis regulation, in the lining epithelium of glandular odontogenic cysts of the jaws. Formalin‐fixed and paraffin‐embedded tissue sections of three glandular odontogenic cysts and six dentigerous cysts were immunostained with a standard avidin‐biotin peroxidase procedure, after microwave antigen retrieval. The glandular odontogenic cysts showed immunoreactivity for bcl‐2 protein in the basal and suprabasal layers, while staining in dentigerous cysts was basal or focal. Most mucous cells and superficial cuboidal cells were negative. The percentage of Ki‐67‐ or p53‐positive cells was lower in glandular odontogenic cysts compared with dentigerous cysts. The findings suggest that the biological behavior of glandular odontogenic cysts may be associated with deregulation of cell death in the lining epithelium, while cell proliferation and p53 status do not seem to play a significant role.
Argyrophilic nucleolar organizer regions (AgNORs) in odontogenic myxoma (OM) and ameloblastic fibroma (AF)
Authors: Martins Cristiane , Carvalho Yasmin Rodarte , Auxiliadora Vieira do Carmo Maria
Published: March 2003

Abstract: Ten cases of odontogenic myxoma (OM) and six cases of ameloblastic fibroma (AF) were subjected to comparative analysis by the AgNOR technique, in order to determine a possible difference in cell proliferation index between these lesions. The mean AgNOR number of the mesenchymal component of AF was compared with its epithelial component and the difference was not found to be statistically significant. The mean AgNOR index of the AF group was significantly higher than that of the OM group. Moreover, the mesenchymal component of AF demonstrated increased AgNOR numbers compared with that of OM (P<0.05). These results suggest that the epithelial and mesenchymal components of AF may have similar cell proliferative activity. However, the cell proliferative index of this lesion seems to be higher than that of OM.
Focal lymphocytic infiltration in aging human palatal salivary glands: a comparative study with labial salivary glands
Authors: Vered Marilena , Buchner Amos , Haimovici Elena , Hiss Yehuda , Dayan Dan
Published: March 2003

Abstract: Investigation of age‐related prevalence of various types of focal lymphocytic infiltration (FLI) and degrees of histomorphologic changes was conducted on 120 biopsies of palatal and labial salivary glands (PSG and LSG, respectively) obtained from autopsy subjects free of salivary gland tumors/diseases. Biopsies were divided into young (<30 years, n=30), adult (30–60 years, n=45) and old (>60 years, n=45) age groups. A modified Chisholm & Mason grading system was used to record grades of FLI and a modified Greenspan et al. system was used to evaluate the severity of histomorphologic changes. The prevalence of FLI in PSG increased significantly from 10% in the young group to 46.6% in the old group (P=0.0012). No significant changes were found with aging in LSG. FLI was significantly more prevalent in the adult and old age groups in PSG as compared with LSG (P=0.015 and P=0.003, respectively). Both glands demonstrated significant histomorphologic changes among age groups (p<0.0001); however, these changes were significantly less common in the old age group in PSG as compared to LSG (P=0.003). In cases showing severe histomorphologic changes, FLI was not present. Therefore, FLI should not be considered as part of the deteriorating histomorphologic changes that are usually encountered in salivary glands with aging. The immunologic profile of these infiltrates should be further clarified to understand their role, both in physiologic and pathologic conditions.
Cultured pulp fibroblasts: are they suitable for in vitro cytotoxicity testing?
Authors: van Wyk C. W. , Olivier A. , Maritz J. S.
Published: March 2003

Abstract: The use of cell cultures to test the biocompatibility of dental materials is gaining in importance. Any cytotoxic effects that restorative materials may have will be on the dental pulp and for that reason cultured pulp cells should be the model of choice for biocompatibility testing. The aim of this investigation was to study the growth and morphologic characteristics and toxic response of human pulp lines and to compare these parameters to those of human buccal mucosa fibroblasts. Twenty‐one specimens of pulp tissue and six from buccal mucosa were cultured using standard techniques. Six pulp cell lines were cultured successfully as were all six from the buccal mucosa specimens. From these specimens, 12 growth curves were computed. To study the morphology of the cultured cells, they were observed microscopically and classified into three morphological types: slender elongated cells (type I), epithelioid shaped cells (type II) and large stellate cells (type III). Their numbers and proportions were determined for each cell line and compared statistically. To gauge sensitivity to toxic materials, cells were exposed to concentrations of arecoline. An analysis of the growth curves showed no statistical difference between pulp cells and buccal mucosa cells; the slopes of the curves, however, differed significantly between individual cell lines, and these individual differences were greater among pulp cell lines. The morphology of the pulp and mucosa fibroblasts was similar microscopically. There was no significant difference between the number and proportion of the cell types in the two groups, but there were significant differences between the individual cell lines. Pulp cells showed a greater inhibition of growth when exposed to arecoline. Because pulp fibroblasts are difficult to culture, their reported survival rate is poor; due to the differences that exist between individual cell lines, we conclude that pulp cells when used as single cell lines or even pooled may not be ideal for testing biocompatibility, especially if reproducibility is a prerequisite. Any evaluation will require tests on not one, but several cell lines in order to minimize the effect of inter‐cell‐line differences. Their greater sensitivity to toxic substances, on the other hand, may show that pulp cells could be more sensitive indicators of cytotoxicity.
Midfacial granuloma syndrome or an inflammatory non‐specific disease? A case report
Authors: Torre Valerio , Bucolo Sebastiano , Galletti Bruno , Cavallari Vittorio
Published: March 2003

Abstract: We report a case of idiopathic midline destructive disease in a 57‐year‐old man. The patient had a non‐specific histological pattern in biopsies obtained from the nose and upper lip, characterized by a granulomatous reaction with progressive destruction of the tissues. The patient’s general medical history was non‐contributory. Clinical and laboratory data did not support any feasible etiology for this destructive process. The patient was treated with prednisone until the discovery of type II diabetes mellitus (never diagnosed before) and was then in turn treated only with oral antidiabetic therapy. Follow‐up controls revealed progressive reduction of the symptoms and of the nasal and lip lesions and total remission of symptoms up to 2 years after the onset of the disease. We discuss the diagnostic and subsequent therapeutic problems in the management of the midline necrotizing lesions.
Epidemiological survey of oral submucous fibrosis and leukoplakia in aborigines of Taiwan
Authors: Yang Yi‐Hsin , Lee Hsiu‐Yu , Tung Sen , Shieh Tien‐Yu
Published: March 2003

Abstract: A population‐based survey was designed to investigate the prevalence of areca/betel quid chewing, oral submucous fibrosis and leukoplakia in a typical aboriginal community of southern Taiwan. Three hundred and twelve people 20 years of age or older were collected in the study. The prevalence of chewing areca/betel quid was 69.5%, with an average of 17.3 portions a day for an average 24.4 years. More women (78.7%) than men (60.6%) chewed areca/betel quid. The prevalences of oral submucous fibrosis and leukoplakia were 17.6% and 24.4%, respectively. It was found that the odds ratio for chewing areca/betel quid and having at least one of the above oral mucosal lesions was 8.21. Any additional smoking or drinking habits were not significant for having oral mucosal lesions. Although the areca/betel quid in Taiwan does not contain any tobacco, a significant association was still identified between areca/betel quid chewing and oral mucosal lesions.
Absence of leukocyte microchimerism in oral lichen planus (OLP): an in situ hybridisation study
Authors: Lombardi T. , Philippeaux M.‐M. , Hadengue A. , Samson J. , Borisch B. , Rubbia‐Brandt L.
Published: March 2003

Abstract: Oral lichen planus (OLP) is a relatively common chronic inflammatory disease. The majority of patients are between 30 and 50 years of age with a higher incidence in females. The aetiology is unknown and various hypotheses on the pathogenic mechanisms, including autoimmunity, have been proposed over the years. In the present study, we investigated whether leukocyte microchimerism, a biological situation implicated in the aetiology of some autoimmune diseases, might play a role in the pathogenesis of OLP. We used in situ hybridisation to identify Y chromosome DNA in a series of formalin‐fixed paraffin‐embedded oral mucosa biopsies of women with established clinical and histological disease who had given birth to a male child. The positive control, two mucosal specimens from a man with OLP, showed over 90% of keratinocytes and cells within the inflammatory infiltrate, a positive nuclear signal. The negative control, biopsies from three women having carried only female foetuses and one nulliparous woman, all with OLP, did not show any nuclear signal. In the fifteen selected cases of OLP biopsies from women who had only male offspring, nucleated cells containing the Y chromosome were not detected within the chronic inflammatory infiltrate. These results suggest that unlike some other immunologically mediated diseases, leukocyte microchimerism does not seems to be involved in the pathogenesis of OLP.
Demonstration of Epstein–Barr virus in odontogenic and nonodontogenic tumors by the polymerase chain reaction (PCR)
Authors: Jang H.‐S. , Cho J.‐O. , Yoon C.‐Y. , Kim H.‐J. , Park J.‐C.
Published: March 2003

Background: Although considerable insight has been gamed into Epstein–Barr virus (EBV) as an important etiologic factor in various tumors, virtually little is known about the relationship between EBV genes and oral tumors.

Method: Thirty‐two cases of nonodontogenic tumor (16 squamous cell carcinomas, 11 salivary gland tumors, 1 malignant lymphoma, 1 spindle cell sarcoma, 1 osteogenic sarcoma, 1 malignant fibrous histiocytoma and 1 verrucous carcinoma), 17 cases of odontogenic tumor (17 ameloblastomas, the most important and common type of odontogenic tumor) and 12 cases of normal oral tissue (8 normal gingival tissues and other oral mucosa) were examined for the presence of EBV‐DNA, with primers specific for the BamW, BNRF1, BMLF1, BamC, IR3, BMRF1, EBNA‐2A BamhY, and EBNA‐2B BamhY region of the EBV genome by the polymerase chain reaction (PCR).

Results: Fifty‐three percent (17/32) of nonodontogenic tumors, forty‐eight percent (8/17) of ameloblastomas, and ninety‐two percent (11/12) of normal oral tissues were positive for EBV‐DNA. Of the EBV‐DNA, BMLF1 demonstrated the strongest reactivity in the nonodontogenic tumors, and BamC demonstrated the strongest reactivity in the ameloblastomas and normal oral mucosae.

Conclusions: Taken into account with the expression of different EBV genes in odontogenic and nonodontogenic tumors, these findings suggest that even though odontgenic tumors and nonodontogenic tumors are relatively unique, the appearance of different EBV genes seems to suggest the complicated roles that the EBV genes play.
Marsupialization inhibits interleukin‐1α expression and epithelial cell proliferation in odontogenic keratocysts
Authors: Ninomiya Tomohiro , Kubota Yasutaka , Koji Takehiko , Shirasuna Kanemitsu
Published: March 2003

Background:   Marsupialization results in the reduction of odontogenic cyst size. Interleukin‐1α (IL‐1α) is thought to play a crucial role for the expansion of odontogenic keratocysts. The aim of this study was to investigate the effects of marsupialization on the expression of IL‐1α and on the proliferating activity of a lining epithelium in odontogenic keratocysts.

Methods:   The concentrations of IL‐1α, interleukin‐6 (IL‐6) and tumor necrosis factor‐α (TNF‐α) in the intracystic fluids of odontogenic keratocysts were measured by the enzyme‐linked immunosorbent assay (ELISA). The expression of IL‐1α mRNA in odontogenic keratocysts was measured before and after marsupialization by in situ hybridization. The expression of IL‐1α and epithelial cell‐proliferating activities in odontogenic keratocysts were also measured by immunohistochemistry using antibodies for human IL‐1α and Ki‐67 antigen, respectively.

Results:   The intracystic fluid levels of IL‐1α were significantly higher than those of IL‐6 and TNF‐α in odontogenic keratocysts. In situ hybridization and immunohistochemistry showed that strong expression of IL‐1α mRNA and protein was mainly detected in the epithelial cells of odontogenic keratocysts. After marsupialization, the signal intensities for IL‐1α mRNA and protein were significantly decreased. In addition, the Ki‐67 labeling index of the epithelial cells was decreased proportionally with the grade of IL‐1α mRNA expression after the marsupialization.

Conclusion:   Our findings suggest that marsupialization may reduce the size of odontogenic keratocyst by inhibiting IL‐1α expression and the epithelial cell proliferation.
Endovascular papillary hemangioma of the lip
Authors: Ide Fumio , Kusama Kaoru
Published: March 2003

We present a previously undescribed, intravenously occurring papillary hemangioma of the lip in a 10‐year‐old girl. Maze‐like anastomosing capillary loops were found within the numerous, dilated veins widely distributed in the submucosa. These peculiar endovascular papillae of bland endothelial cells plugged the lumens and bore a striking resemblance to the renal glomeruli. Thrombi or other associated vascular lesions could not be identified. Because of its histological similarity to endovascular papillary angioendothelioma‐like tumor, we designate this tumor as endovascular papillary hemangioma.
Risk of oral cancer associated with human papillomavirus infection, betel quid chewing, and cigarette smoking in Taiwan — an integrated molecular and epidemiological study of 58 cases
Authors: Chen Paul Chih‐Hsueh , Kuo Chih , Pan Chin‐Chen , Chou Ming‐Yung
Published: March 2003

Background:  The association between oral squamous cell carcinoma (OSCC) and human papillomavirus (HPV) 6, 11, 16 and 18 is uncertain. Past reports varied in the methodology and results. We conducted this study using in situ PCR in situ hybridization (ISH) assay which was considered as the most sensitive method for detection of viral DNA. We undertook an epidemiologic survey about the history of betel quid chewing and cigarette smoking, since these habits are common in Taiwan.

Methods:  In situ PCR ISH was performed on the tumor specimens from 29 patients with OSCC and the oral mucosal specimens from 29 patients without OSCC. Their betel quid chewing and cigarette smoking histories were also reviewed.

Results:  HPV16, HPV18, betel quid chewing and cigarette smoking were statistically significant risk factors in univariate analysis. HPV6 and 11 were not. Multivariate analysis showed that HPV16 infection (adjusted Odds ratio = 11.20) and betel quid chewing (adjusted Odds ratio = 17.06) remained to be independent factors for OSCC.

Conclusions:  Our results showed that HPV16 and betel quid chewing were two major risk factors for OSCC in Taiwan, indicating that they act through different mechanisms in the pathogenesis of OSCC.
Lymphangioma involving the mandible: immunohistochemical expressions for the lymphatic proliferation
Authors: Park Young Wook , Kim Soung Min , Min Bong Gi , Park In Woo , Lee Suk Keun
Published: March 2003

We report a case of lymphangioma involving oral mucosa and mandible of an elderly female. The surgical and radiological examinations indicated that the lymphangioma was mainly distributed in the labial mucosa tissue, but had gradually extended into the periosteum and intrabony space of mandible. Immunohistochemical staining was also performed using antiseras of α‐smooth muscle actin (α‐SMA), von Willebrand factor (vWF), angiogenin, vascular endothelial growth factor (VEGF), and proliferating cell nuclear antigen (PCNA) to elucidate the pathogenetic implications of the intraosseous lymphangioma. The present case of lymphangioma showed strong immunohistochemical reactivity of angiogenin and vWF, while it showed weak reactions of VEGF and PCNA. The immunostaining of α‐SMA disclosed an abnormally thinned and discontinuous smooth muscle layer in the lymphatics. Both the X‐rays and histological examination showed that the lymphangioma lesion was gradually extending into the adjacent osteoporotic marrow space of mandible. Therefore, we believe that the present case of intraosseous lymphangioma, which showed the harmatomatous growth of the lymphatics into the marrow space of mandible, is closely related to osteoporotic changes of old age.
The Regulation of Motile Activity in Fish Chromatophores
Authors: FUJII* RYOZO
Published: March 2003

Chromatophores, including melanophores, xanthophores, erythrophores, leucophores and iridophores, are responsible for the revelation of integumentary coloration in fish. Recently, blue chromatophores, also called cyanophores, were added to the list of chromatophores. Many of them are also known to possess cellular motility, by which fish are able to change their integumentary hues and patterns, thus enabling them to execute remarkable or subtle chromatic adaptation to environmental hues and patterns, and to cope with various ethological encounters. Such physiological color changes are indeed crucial for them to survive, either by protecting themselves from predators or by increasing their chances of feeding. Sometimes, they are also useful in courtship and mutual communications among individuals of the same species, leading to an increased rate of species survival. Such strategies are realized by complex mechanisms existing in the endocrine and/or nervous systems. Current studies further indicate that some paracrine factors such as endothelins (ETs) are involved in these processes. In this review, the elaborate mechanisms regulating chromatophores in these lovely aquatic animals are described.
Mutational Analysis of the Modulation of Tyrosinase by Tyrosinase‐Related Proteins 1 and 2 In Vitro
Authors: MANGA PRASHIELA , SATO KIYOSHI , YE LIYAN , BEERMANN FRIEDRICH , LAMOREUX M. LYNN , ORLOW SETH J.
Published: March 2003

The albino (tyrosinase, Tyrc), brown (tyrosinase‐related protein 1, Tyrp1b) and slaty (tyrosinase‐related protein 2, tyrp2slt) loci are all involved in the regulation of melanogenesis. Phenotypes of inbred mice mutant at two or more of these loci are not always explicable by simple summation of the established or suspected catalytic functions of the gene products. These phenotypes suggest that relationships among the proteins extend beyond the obvious fact that they catalyze different steps in the same melanogenic pathway, and that they may also interact intimately in such a way that a mutation in one impacts the function of the other(s). Previous studies have attributed catalytic activities to each member of this trio; however, it has been difficult to study the proteins individually, either in vivo or in tissues or cells. Therefore, we undertook to transfect the genes, in revealing combinations, into COS‐7 cells (which have no melanogenic apparatus of their own) to clarify the interacting functions of their encoded proteins. Specifically, we attempted to evaluate the effects of Tyrp1 and Tyrp2 proteins on tyrosinase protein. We report evidence that Tyrp1 stabilizes tyrosinase, confirming previous observations, and, in addition, demonstrate that Tyrp1 decreases tyrosinase activity. By contrast, Tyrp2 increases tyrosinase activity by stabilizing the protein. We conclude that both Tyrp1 and Tyrp2, in addition to other catalytic functions they may possess, act together to modulate tyrosinase activity.
The Dilute Locus and Griscelli Syndrome: Gateways Towards a Better Understanding of Melanosome Transport
Authors: WESTBROEK WENDY , LAMBERT JO , MARIE NAEYAERT JEAN
Published: March 2003

In this review an overview of recent advances in the understanding of melanosome movement within epidermal melanocytes is given. Exploration of the molecular events involved in and determining the process of melanosome transport, as an essential part of human pigmentation, could lead to the identification of agents that augment, or down‐regulate the transfer of melanosomes to surrounding keratinocytes. This would present a major breakthrough in the possibilities to influence pigmentation and related disorders, of great concern to some patients. Moreover, melanosome transport offers a good model to study mammalian organelle trafficking and its key players in general.
Tyrp1 and Oculocutaneous Albinism Type 3
Authors: Sarangarajan Rangaprasad , Boissy Raymond E.
Published: March 2003

Tyrosinase‐related protein 1 (Tyrp1) is a melanocyte‐specific gene product involved in eumelanin synthesis. Mutations in the mouse Tyrp1 gene are associated with brown pelage, and in the human TYRP1 gene with oculocutaneous albinism type 3 (OCA3). In the murine system, Tyrp1 expresses significant dihydroxyindole carboxylic acid oxidase (i.e. DHICA oxidase) activity. However, in humans, TYRP1 is enigmatic in that despite extensive efforts focused on the study of its function, its actual role in the human melanocyte is still unclear. There is mounting evidence demonstrating that in addition to its role in eumelanin synthesis, Tyrp1 is involved in maintaining stability of tyrosinase protein and modulating its catalytic activity. Tyrp1 is also involved in maintenance of melanosome ultrastructure and affects melanocyte proliferation and melanocyte cell death. The current review is an attempt to consolidate our understanding of the role of Tyrp1 in the melanocyte.
Development of Cutaneous Amelanotic Melanoma in the Absence of a Functional Tyrosinase
Authors: Cohen‐Solal Karine A. , Reuhl Kenneth R. , B. Ryan Kevin , Roberts Kathleen G. , Chen Suzie
Published: March 2003

Lack of characteristic pigmentation and a wide range of clinical presentations account for the diagnostic challenge associated with amelanotic malignant melanoma. Experimental studies of this important human cancer have been hampered by the lack of an appropriate animal model. We previously described a transgenic mouse line (TG‐3) that spontaneously develops pigmented cutaneous melanoma. F1 crosses were generated with TG‐3 and several albino strains, and backcrosses were then made with the albinos. In the present report, we describe the restricted development and characterization of cutaneous amelanotic melanoma in these albino transgenic backcrosses. The incidence and behavior of melanoma in these mice were monitored. A high incidence (80–100%) of spontaneous amelanotic melanoma was observed in albino transgenic mice derived from backcrosses with A, AKR, FVB, and SJL strains. The lowest incidence (30%) was obtained in BALB/c‐derived crosses. No tumors were observed in non‐transgenic mice. Immunohistochemical and western blot analyses using antibodies against three melanocyte‐specific markers of the tyrosinase family of proteins confirmed that the tumors were composed of amelanotic melanocytes. Furthermore, the presence of numerous premelanosomes observed by electron microscopy further supported the melanocytic origin of these tumors. Previous in vitro studies on human melanoma have suggested that cutaneous amelanotic melanoma was evolving from pre‐existing pigmented cutaneous melanoma. However, our results indicate that it can occur directly, as evidenced by the appearance of cutaneous amelanotic melanoma in the tyrosinase‐deficient albino mice. These mice represent a potentially valuable model for studying the mechanistic, diagnostic, and therapeutic features of this highly malignant neoplasm.
Advanced Chemical Methods in Melanin Determination
Authors: Wakamatsu Kazumasa , Ito Shosuke
Published: March 2003

Among the biopolymers, melanins are unique in many respects. The other essential biopolymers – proteins, nucleic acids, and carbohydrates – are chemically well characterized; their precursors (monomer units) and modes of connection between the monomer units are known, and sequences of their connection can be determined with well‐established methodologies. In contrast, we still do not have a method to determine accurately the ratio of various units present in melanins. This is largely because of the chemical properties of melanins, such as their insolubility over a broad range of pH, the heterogeneity in their structural features, and also because of the lack of methods that can split melanin polymers into their monomer units (all other biopolymers can be hydrolysed to the corresponding monomer units). To overcome this difficulty, we developed a rapid and sensitive method for quantitatively analysing eumelanin and pheomelanin in biological samples by chemical degradation methods followed by HPLC determination. This HPLC microanalytical method for characterizing eumelanin and pheomelanin has become a useful tool for the study of melanogenesis. This review will summarize the usefulness and limitations of the various chemical and spectrophotometric methods used to analyse melanins at the biochemical, cellular, and tissue levels. Emphasis is given on the usefulness of 4‐amino‐3‐hydroxyphenylalanine as a specific marker of pheomelanin.
Progressive Appearance of Pigmentation in Amelanotic Melanoma Lesions
Authors: Cohen‐Solal Karine A. , Crespo‐Carbone Steven M. , Namkoong Jin , Mackason Kerine R. , Roberts Kathleen G. , Reuhl Kenneth R. , Chen Suzie
Published: March 2003

We previously described a transgenic mouse line (TG‐3) that spontaneously develops pigmented cutaneous melanoma. The generation of several albino mice that developed amelanotic melanoma has also been reported. In this report, we describe an unanticipated result with crosses between C57BL/6‐c2j and TG‐3 mice. C57BL/6‐c2j has the same genetic background as TG‐3 (C57BL/6), except for a single base mutation (nucleotide 291) in the tyrosinase locus, resulting in albino coat colour. Only albino F2 mice generated from (TG‐3 × C57BL/6‐c2j) F1s were selected for further studies. Mice that contained the transgene showed a very high incidence of tumor development as early as 4–6 weeks of age. Raised amelanotic tumors developed on the ear pinnae and perianal region in young F2 albino mice, similar phenotypes as those described earlier for the other albino inbred strains. However, with time, these amelanotic tumors not only increased in size, but unexpectedly developed foci of dark pigmentation. DNA sequence analysis on reverse transcriptase‐polymerase chain reactions (RT–PCRs) of tyrosinase mRNA showed that the original tyrosinase mutation was still present in the tumors, indicating that no reversion at this nucleotide had occurred in the tumors. Two different tyrosinase activity assays were used and tyrosinase activity was detected in most tumor samples. Furthermore, Western blot analysis demonstrated various levels of tyrosinase protein in ear tumor samples. These results suggest that tyrosinase and/or melanin are not directly involved in the establishment of melanoma, but that late events occurring within the tumors may generate some tyrosinase activity and production of melanin.
Chediak–Higashi Syndrome: A Rare Disorder of Lysosomes and Lysosome Related Organelles
Authors: Shiflett Shelly L. , Kaplan Jerry , WARD Diane McVey
Published: March 2003

Chediak–Higashi Syndrome (CHS) is a rare autosomal recessive disorder characterized by severe immunologic defects including recurrent bacterial infections, impaired chemotaxis and abnormal natural killer (NK) cell function. Patients with this syndrome exhibit other symptoms such as an associated lymphoproliferative syndrome, bleeding tendencies, partial albinism and peripheral neuropathies. The classic diagnostic feature of CHS is the presence of huge lysosomes and cytoplasmic granules within cells. Similar defects are found in other mammals, the most well studied being the beige mouse and Aleutian mink. A positional cloning approach resulted in the identification of the Beige gene on chromosome 13 in mice and the CHS1/LYST gene on chromosome 1 in humans. The protein encoded by this gene is 3801 amino acids and is highly conserved throughout evolution. The identification of CHS1/Beige has defined a family of genes containing a common BEACH motif. The function of these proteins in vesicular trafficking remains unknown.
Rac and Rho: The Story Behind Melanocyte Dendrite Formation
Authors: Scott Glynis
Published: March 2003

Melanocyte dendrites are hormonally responsive actin and microtubule containing structures whose primary purpose is to transport melanosomes to the dendrite tip. Melanocyte dendrites have been an area of intense interest for melanocyte biologists, but it was not until recently that we began to understand the mechanisms underlying their formation. In contrast with melanogenesis, for which numerous mutations in pigment producing genes and mouse models have been identified, a genetic defect resulting in impaired dendrite formation has not been found. Therefore, much of the insight into melanocyte dendrites has come from electron microscopy or in vitro culture systems of normal human and murine melanocytes as well as melanoma cell lines. The growth factors that regulate the formation of melanocyte dendrites have been thoroughly studied and it is clear that multiple signalling systems are able to stimulate, and in some cases inhibit, dendrite formation. Recent data points to the Rho family of small guanosine triphosphate (GTP)‐binding proteins as master regulators of dendrite formation, particularly Rac and Rho. In this review I will summarize the progress scientists have made in understanding the structure, hormonal regulation and molecular mediators of melanocyte dendrite formation.
Reduced dental plaque accumulation on composite gold alloy margins
Authors: Goodson J. M. , Shoher I. , Imber S. , Som S. , Nathanson D.
Published: March 2003

Restoration of tooth surfaces with materials that inhibit formation of heavy bacterial plaque accumulations could be important in the treatment of patients with existing oral disease or in reducing the likelihood for periodontal disease. Captek® is a dental gold composite material used to produce copings for ceramometal restorations that has been reported to inhibit plaque accumulation. In this study, the oral bacteria of nine periodontally healthy subjects with a total of 42 gold composite copings were sampled. Contralateral teeth with normal tooth surfaces were also sampled as controls. The quantitative presence of forty bacteria was determined in each sample by DNA:DNA hybridization. The results indicated that the porcelain/gold composite alloy coping surfaces had significantly fewer bacteria than the control normal tooth surfaces (71% reduction). The percentage composition, however, did not differ significantly between surfaces.