bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamic properties of Ti51Pd30Ni19 high‐temperature shape memory alloy under different heat treatment conditions
Authors: Tian Qingchao , Wu Jiansheng
Published: March 2003

Ti51Pd30Ni19 alloy was prepared in a different heat treatment state for retaining different dynamic mechanical properties. It has been found that specimens annealed at 1273 K followed by furnace cooling or by quenching exhibit different phase transformation behaviour. Subsequent annealing at lower temperature (after rolling) does not change the transformation sequence. DMTA (dynamic mechanical thermal analysis) measurement results reveal that the variation of the elastic modulus is different for the two kinds of transformation, which show elasticity softening and elastic step, respectively. The elastic modulus of low‐temperature martensite differs as well. It has been found that damping of the peaks occurs on both heating and cooling the alloy across the phase transformation temperatures. The damping properties, tan δ, of the new phase possess higher values than those of the parent phase.
Effect of selected model parameters on predicted RAFT data
Authors: Gustavsson Joel , Andersson Margareta , Jönsson Pär
Published: March 2003

A new raceway adiabatic flame temperature (RAFT) model has been developed where the effect of injected BOF slag has been considered. A parameter study was performed to evaluate the influence of (i) coke temperature factor, (ii) degree of silica reduction, (iii) coal powder burning degree, (iv) reduction degree of some components in injected BOF slag when leaving raceway, (v) enthalpy of coke burning and (vi) Cp value of coke. The coke burning enthalpy was found to have the largest influence on the absolute value of RAFT. In Swedish blast furnaces, the RAFT is usually kept relatively constant by adjusting the oxygen content in the blast. Therefore, the exchange ratios between the oxygen content in blast and the injected material to retain RAFT were predicted. The burning degree of coal powder was found to have the largest influence when coal powder was evaluated. Silica and silicon carbide reduction was found to have the largest influence when a change of BOF slag rate was evaluated.
The structural peculiarities of the CdTe melt based on the results of the molecular dynamics
Authors: Glazov V. M. , Pavlova L. M.
Published: March 2003

The characteristics of the structure of molten cadmium telluride were calculated using the method of molecular dynamics with the use of a Stillinger‐Weber‐type potential. The potential parameters adopted in Monte Carlo calculations of the structure of cadmium telluride were used. The molecular dynamics calculations were performed for an NVT ensemble at 1373 K. The results were compared with the neutron diffraction data. The Stillinger‐Weber potential was shown to give an insufficiently accurate description of interparticle interactions in cadmium telluride melts. Its reparametrization was required to improve agreement with experiment.
A blast furnace view on slags
Authors: Brämming Mats , Wikström Jan‐Olov
Published: March 2003

In 1982, SSAB, Luleå Works, converted the blast furnace ferrous burden from an acid to an olivine pellet with a high Fe content. This change made it possible to gradually reduce the slag volume to 150 kg per metric ton of hot metal with huge positive effects on the blast furnace operation. SSAB, Oxelösund Works, can present a similar development, initially by increasing the Fe content in sinter and later by converting to a 100% olivine pellet operation in 1995. In addition to a description of the historical development of the properties of SSAB blast furnace slags, this paper describes the technical means and issues as well as the environmental constraints governing future developments of slag volume and chemistry, including effects of changes in burden quality and possible tuyere injection of slag formers.
Soil biodiversity: myth, reality or conning?
Authors: André Henri M. , Ducarme Xavier , Lebrun Philippe
Published: March 2003

The study of soil microarthropod biodiversity is illustrative of problems that are related to other soil organisms (fungi, for instance) or that can be found in other environments (canopy, oceanic sediments, hosts accommodating parasites, etc.). Indeed, the contribution of the soil fauna to global biodiversity remains an enigma even though, in recent years, it has received considerable attention. Our contention is that the debate on soil biodiversity will remain open – and even sterile – as long as adequate sampling methodologies are not set up, critically evaluated and largely used.  First, a critical review of the sampling strategies used for soil microarthropods is presented. In addition to an extensive compilation of publications on extraction method efficiency, articles from two journals devoted to soil biology are compared for two five‐year periods (before and after Erwin's papers and before and after Rio). The most frequently used extraction methods (over 90% of studies) have a poor numerical efficiency (e.g. 7–26% for the Berlese‐Tullgren funnels) and also are selective with respect to their efficiency for certain taxa (variable taxonomic and functional efficiency), 75% of studies are restricted to the upper 10 cm of soil and therefore overlook largely the microarthropod populations, some groups are often neglected, however diversified they are, and the taxonomic resolution tends to become impoverished in recent years.  In the second part of our study, the importance of bias induced by inadequate or restricted sampling strategies on biodiversity estimates is evaluated: densities are dramatically underestimated (down to 14 times less); conversely species aggregation, a factor advocated to explain the existence of numerous soil species, is overestimated; some functional groups may be quite overlooked; the species distribution along a gradient deduced from the sampling may be rather different from that really existing in the soil and interfere with the evaluation of β‐diversity; species richness is often crudely underestimated (down to 50%).  Overall, at most 10% of soil microarthropod populations have been explored and 10% of species described. Obviously, much has still to be done to evaluate soil microarthropod biodiversity andafortioriunderstand the mechanisms underlying it. Improving and renewing the soil sampling strategy is thus a prerequisite to any real advance in our knowledge of this fascinating and obscure domain.
Rate of population change in voles from different phases of the population cycle
Authors: Klemola Tero , Korpimäki Erkki , Koivula Minna
Published: March 2003

Factors involved in causing cyclic vole populations to decline, and in preventing populations from recovering during the subsequent low density phase have long remained unidentified. The traditional view of self‐regulation assumes that an increase in population density is prevented by a change in the quality of individuals within the population itself, but this is still inadequately tested in the field. We compared the population growth of wild field voles (Microtus agrestis) from the low phase (conducted in 1998) with that of voles from the increase phase (conducted in 1999) in predator‐proof enclosures (each 0.5 ha) in western Finland. Within a few months, enclosed vole populations increased to high density, and the realised per capita rate of change over the breeding season did not differ between the populations from different cycle phases. This implies that the recovery of populations from the low phase was not hindered by an impoverishment in quality of individual voles. Accordingly, we suggest that population intrinsic factors (irrespective of the mechanisms they are based on) are unlikely to play a significant role in the generation of cyclic density fluctuations of voles. Instead, we discovered direct density‐dependent regulation in the vole populations. Accurate estimates of population growth and the observed density dependence provide important information for empirically based models on population dynamics of rodents.
Nomadic movement in tropical toads
Authors: Schwarzkopf Lin , Alford Ross A.
Published: March 2003

Dispersal is a critical aspect of the biology of most organisms, but movement patterns are poorly known for most animals. Knowledge of movement patterns allows biologists to construct realistic spatial models, either for theoretical or empirical purposes. Cane toads (Bufo marinus) have high survival rates (30–70% per annum in Australia), but very low recapture rates over long periods in marking studies, suggesting that they may be nomadic. Here we model the movement patterns of cane toads to determine whether they move nomadically. Using radiotracking, we quantified the movements of 64 cane toads, at two widely separated locations in northern Australia. We established that toad movements were indeed nomadic by comparing real movements with those generated by an individual‐based, correlated random walk model that selected randomly from empirical distributions of movement parameters. In the wet season, at both locations, real movements were similar to those generated by the model, indicating that toads moved nomadically during this time of year. During the dry season at both locations, toads used a smaller area and travelled less straight paths than predicted by the model. Nomadic movements were more common and extensive during the wet season, although some individuals moved nomadically at all times of year. To determine whether the model provided a good description of toad movements over the long term, we compared observed disappearance rates from a mark‐recapture study conducted in one of our study sites, with disappearance rates predicted by the model. There was good agreement between these two methods of measuring toad movements. Previous studies indicated that food availability was lowest and desiccation risk and predation risk were highest in the dry season, suggesting that nomadic movement of toads is most extensive when the costs of movement due to desiccation, predation and energy limitation are lowest.
Are endophytic fungi defensive plant mutualists?
Authors: Faeth Stanley H.
Published: March 2003

Endophytic fungi, especially asexual, systemic endophytes in grasses, are generally viewed as plant mutualists, mainly through the action of mycotoxins, such as alkaloids in infected grasses, which protect the host plant from herbivores. Most of the evidence for the defensive mutualism concept is derived from studies of agronomic grass cultivars, which may be atypical of many endophyte‐host interactions. I argue that endophytes in native plants, even asexual, seed‐borne ones, rarely act as defensive mutualists. In contrast to domesticated grasses where infection frequencies of highly toxic plants often approach 100%, natural grass populations are usually mosaics of uninfected and infected plants. The latter, however, usually vary enormously in alkaloid levels, from none to levels that may affect herbivores. This variation may result from diverse endophyte and host genotypic combinations that are maintained by changing selective pressures, such as competition, herbivory and abiotic factors. Other processes, such as spatial structuring of host populations and endophytes that act as reproductive parasites of their hosts, may maintain infection levels of seed‐borne endophytes in natural populations, without the endophyte acting as a mutualist.
The role of legumes as a component of biodiversity in a cross‐European study of grassland biomass nitrogen
Authors: Spehn E. M. , Scherer‐Lorenzen M. , Schmid B. , Hector A. , Caldeira M. C. , Dimitrakopoulos P. G. , Finn J. A. , Jumpponen A. , O'Donnovan G. , Pereira J. S. , Schulze E.‐D. , Troumbis A. Y. , Körner C.
Published: March 2003

To investigate how plant diversity loss affects nitrogen accumulation in above‐ground plant biomass and how consistent patterns are across sites of different climatic and soil conditions, we varied the number of plant species and functional groups (grasses, herbs and legumes) in experimental grassland communities across seven European experimental sites (Switzerland, Germany, Ireland, United Kingdom (Silwood Park), Portugal, Sweden and Greece). Nitrogen pools were significantly affected by both plant diversity and community composition. Two years after sowing, nitrogen pools in Germany and Switzerland strongly increased in the presence of legumes. Legume effects on nitrogen pools were less pronounced at the Swedish, Irish and Portuguese site. In Greece and UK there were no legume effects. Nitrogen concentration in total above‐ground biomass was quite invariable at 1.66±0.03% across all sites and diversity treatments. Thus, the presence of legumes had a positive effect on nitrogen pools by significantly increasing above‐ground biomass, i.e. by increases in vegetation quantity rather than quality. At the German site with the strongest legume effect on nitrogen pools and biomass, nitrogen that was fixed symbiotically by legumes was transferred to the other plant functional groups (grasses and herbs) but varied depending on the particular legume species fixing N and the non‐legume species taking it up. Nitrogen‐fixation by legumes therefore appeared to be one of the major functional traits of species that influenced nitrogen accumulation and biomass production, although effects varied among sites and legume species. This study demonstrates that the consequences of species loss on the nitrogen budget of plant communities may be more severe if legume species are lost. However, our data indicate that legume species differ in their N2fixation. Therefore, loss of an efficient N2‐fixer (Trifoliumin our study) may have a greater influence on the ecosystem function than loss of a less efficient species (Lotusin our study). Furthermore, there is indication that P availability in the soil facilitates the legume effect on biomass production and biomass nitrogen accumulation.
Top‐down, bottom‐up, or side to side? Within‐trophic‐level interactions modify trophic dynamics of a salt marsh herbivore
Authors: Moon Daniel C. , Stiling Peter
Published: March 2003

Many factors can influence the top‐down and bottom‐up dynamics of phytophagous insects. Although interactions between herbivore species have been frequently shown to be ecologically important, the effects of such horizontal trophic interactions on the relative roles of top‐down and bottom‐up forces have gone largely unstudied. In this paper we report on the results of a factorial field experiment in which we examined the effects of within‐trophic‐level interactions on the top‐down and bottom‐up dynamics of a salt marsh planthopper.  We manipulated the bottom‐up effects of plant quality by increasing soil salinity, and manipulated top‐down effects by decreasing the intensity of parasitoid attack with yellow sticky traps that removed hymenopteran parasitoids. We applied these treatments to plots in two patches of the host plant, one with low densities of lepidopteran stem borer larvae, and one with high densities of stem borers. We maintained the treatments and monitored planthopper density for ten months, from March through December 1999. Increased salinity significantly increased planthopper density within one month of the first application of salt. The rapid response of the planthopper to salt treatments suggested a chemical mechanism, perhaps mobilization of bound nitrogen. Yellow sticky traps, although significantly reducing parasitism of planthopper eggs, had little impact on hopper density. The density of lepidopteran stem borers, however, had an even greater impact on planthopper density than did salt treatments, with high stem borer plots supporting much lower densities of hoppers. Stem borer density also reduced the response of the planthopper to other treatments, especially salt supplementation. The results of this study show that the impact of within‐trophic‐level interactions can significantly change herbivore trophic dynamics and can be even more important than either top‐down or bottom‐up effects in determining herbivore density.
Association of aberrant p53 and p21WAF1 immunoreactivity with the outcome of oral verrucous leukoplakia in Taiwan
Authors: Chang Kuo‐Wei , Lin Shu‐Chun , Kwan Po‐Cheung , Wong Yong‐Kie
Published: March 2003

Abstract: The expression of p53 and p21WAF1 in 53 oral verrucous leukoplakias (OVLs), mostly non‐dysplastic lesions, was investigated to ascertain the role of such events in malignant conversion. Immunohistochemical analysis revealed aberrant p53 and p21WAF1 immunoreactivity in 51% (27 cases) and 75% (40 cases), respectively. After an average follow‐up period of three and a half years, histopathological examination revealed that 22 (42%) cases had developed oral squamous cell carcinoma (OSCC), 14 (26%) cases had undergone recurrence, and 17 (32%) cases were free of disease. The oncogenic potential of this subset of premalignant lesions warrants attention. A significant difference in the frequency of OSCC progression/recurrence was noted in lesions bearing aberrant immunoreactivity of either p53 (93% vs 42%; P=0.00008) or p21WAF1 (80% vs 32%; P=0.002) in comparison with lesions without immunoreactivity. This study suggested that the aberrant immunoreactivity of p53 and p21WAF1 may represent important alterations of OVL and could affect the outcome of this lesion.
Effect of phenytoin on the production of interleukin‐6 and interleukin‐8 in human gingival fibroblasts
Authors: Modéer T. , Domeij H. , Andurén I. , Mustafa M. , Brunius G.
Published: March 2003

Abstract: The in vitro effect of phenytoin (PHT) on the production of interleukin‐6 (IL‐6) and interleukin‐8 (IL‐8) in human gingival fibroblasts, challenged with or without interleukin‐1β (IL‐1β), was studied. PHT (20 μg/ml) alone increased the mRNA level for both IL‐6 and IL‐8, as well as synergistically enhancing the production of IL‐6 and IL‐8, at both transcriptional and translational level in fibroblasts challenged with IL‐1β (30 pg/ml). The stimulatory effect of PHT on IL‐1β‐induced IL‐6 production was strongly reduced by the specific cyclooxygenase‐2 inhibitor NS‐398 (1 μM). The anti‐inflammatory drug, dexamethasone (1 μM), abolished the production of both IL‐6 and IL‐8 in gingival fibroblasts challenged with PHT in the presence or absence of IL‐1β. The ability of PHT, alone as well as in combination with IL‐1, to upregulate the production of IL‐6 and IL‐8 in human gingival fibroblasts may contribute to enhanced recruitment and activation of inflammatory cells. This effect of PHT may thereby give a prerequisite for the establishment of an interaction between cytokines and connective tissue cells in the periodontal tissue, which is suggested to lead to gingival overgrowth.
Immunolocalisation of cartilage‐derived retinoic acid‐sensitive protein in pleomorphic adenoma of the parotid salivary gland
Authors: Devlin H. , Sloan P.
Published: March 2003

Abstract: Pleomorphic adenoma of the parotid salivary glands often contains chondroid elements and may exhibit cartilaginous and osseous differentiation, although the latter is extremely rare. Twenty‐nine pleomorphic adenomas (PAs) of the parotid gland were examined immunohistochemically for the distribution of cartilage‐derived retinoic acid‐sensitive protein (CD‐RAP), a recently described marker of chondrocytes, which may be important in the morphogenesis and development of the salivary gland. In the normal parotid gland, the ductal cells expressed CD‐RAP, but not the myoepithelial cells. In the pleomorphic salivary adenomas, the duct‐like cells, but not the myoepithelial cells, expressed CD‐RAP. Since many authorities consider myoepithelial cells to be the source of the chondroid matrix, it is surprising that these cells do not express the chondrocytic marker, CD‐RAP. Putative neoplastic myoepithelium in the pleomorphic adenoma and some cells in the myxochondroid areas expressed S‐100 and calponin.
Expression of adhesion and activation molecules in human buccal epithelial cell lines and normal human buccal epithelium in situ
Authors: Farmer Ian , Freysdottir Jona , Dalghous Abdulbaset M. , Fortune Farida
Published: March 2003

Abstract: An in vitro culture system may be used to analyse interactions between T cells and epithelium. We have analysed two human buccal squamous epithelial cell lines: SqCC/Y1, derived from a buccal carcinoma, and SVpgC2a, an SV‐transformed healthy buccal squamous epithelium. Under serum‐free culture conditions, the cell lines resemble normal buccal squamous epithelium in situ in their expression of MHC class I, CD29 (β1 integrin), CD40, CD44, CD54 (ICAM‐1), CD58 (LFA‐3), CD95 (Fas), and E‐cadherin. Furthermore, when the SVpgC2a cell line was treated with T‐cell derived cytokines, upregulation of CD40 expression was observed when the cells were treated with IL‐4, whereas IFN‐γ caused upregulation in expression of CD40, CD54 and MHC class II. These buccal squamous epithelial cell lines, therefore, provide a good tool for analysing interactions between epithelium and T cells in vitro.
Odontogenic tumors in Chile: a study of 362 cases
Authors: Ochsenius Germán , Ortega Ana , Godoy Luis , Peñafiel Cristian , Escobar Enrico
Published: March 2003

Background:  Odontogenic tumors are infrequent lesions. Thus, the review of a large number of cases becomes a necessity for both the pathologist and the clinician. Studies on odontogenic tumors have been published in many parts of the world, but there is little information available in the English language literature on the relative frequency of odontogenic tumors in Latin America. The aim of this study was to determine the relative frequency of this heterogeneous group of lesions in a Chilean population, and to compare these data with previous reports.

Methods:  We reviewed the records of 28,041 specimens from 1975 to 2000 in the Oral Pathology Referral Institute (IREPO), and using the criteria for histological typification published by the World Health Organization in 1992, we reclassified the odontogenic tumors.

Results:  We confirmed a total of 362 odontogenic tumors. The frequency of odontogenic tumors as a percentage of all pathological specimens in our institute was 1.29%. The most frequent histological type was odontomas (44.7%), followed by ameloblastomas (20.4%) and myxomas (8.8%).

Conclusions:  Odontogenic tumors are uncommon lesions in the Chilean population and malignant odontogenic tumors are very rare. The relative frequency of various types of odontogenic tumors, as well as the age and gender distribution are similar to those reported in the North American series and different from those found in recently published Asian and African series.
Disturbed tooth eruption in osteopetrotic (op/op) mice: histopathogenesis of tooth malformation and odontomas
Authors: Ida‐Yonemochi Hiroko , Noda Tadashi , Shimokawa Hitoyata , Saku Takashi
Published: March 2003

Background:  Odontoma‐like structures are formed in the jaw bone of osteopetrotic (op/op) mice, which have a congenital deficiency in osteoclastic differentiation due to the absence of functional macrophage colony‐stimulating factor (M‐CSF).

Methods:  To clarify the histopathogenesis of tooth malformation and odontoma‐like structures, a 2‐year postnatal process of development of the op/op mandibular incisor was examined radiologically and histologically. At the same time, extracellular matrix (ECM) remodeling around tooth germs was analyzed immunohistochemically.

Results:  Abnormal forms of op/op tooth germ were noticeable even at 3 days after birth on a radiogram. Histologically, op/op mice were clearly distinguished by the disappearance of dental follicular space at 3 days. With aging, bone trabeculae, which were not remodeled, penetrated into op/op tooth germs and divided them into several daughter germs, which were recognized as odontomas. In mandibular incisor bodies, the immature ECM components, such as heparan sulfate proteoglycan and tenascin, were preserved diffusely in the dental papilla/pulp, which indicates that maturation of the stroma does not take place in op/op mandibular incisors.

Conclusion:  The observation suggests that the disturbed morphogenesis of op/op tooth germs is functionally explained by the disordered immunolocalization of ECM molecules, and that the dental follicular space is essential for normal tooth development because it prevents bone penetration into the tooth germs.
Subcellular localization of beta‐catenin in malignant cell lines and squamous cell carcinomas of the oral cavity
Authors: Gasparoni A. , Chaves A. , Fonzi L. , Johnson G. K. , Schneider G. B. , Squier C. A.
Published: March 2003

Background:  Beta‐catenin, an E‐cadherin‐associated protein involved in cell–cell adhesion and signaling, has been hypothesized to translocate to the nucleus and activate transcription in several human cancers, including oral squamous cell carcinomas (OSCC).

Methods:  In the present study, we analyzed the subcellular localization of beta‐catenin in cultures of human oral normal and malignant (cell lines SCC15 and SCC25) keratinocytes and in 24 frozen samples of oral squamous cell carcinomas by a double‐staining technique for nucleic acids and beta‐catenin. Growth potential, as assessed by cell count at different time periods, was established for normal, SCC15 and SCC25 cell lines; oral squamous cell carcinomas were classified according to the histopathological and malignancy indexes.

Results:  Beta‐catenin localized at the plasma membrane in the normal and SCC15 cells, not in the SCC25 cells, where it localized mostly in the perinuclear and nuclear areas. In the growth assays, SCC25 cell lines proliferated faster than in normal and SCC15 cells over a period of 6 days (cell numbers were significantly different, P < 0.0001). Carcinoma sections showed a combination of membranous, cytoplasmic and, in few invading epithelial islands of two tumors, nuclear localization of beta‐catenin.

Conclusions:  In oral squamous cell carcinomas, nuclear beta‐catenin staining was observed only within invading islands of two carcinomas deep in the underlying connective tissue. On the basis of this study, we conclude that intranuclear beta‐catenin does not appear to be a common finding in oral squamous cell carcinomas and that a clear association between intranuclear beta‐catenin and histopathological and malignancy indexes in vivo could not be established.
Expression of type 2 nitric oxide synthase and p53 in Warthin's tumour of the parotid
Authors: Brennan Peter A. , Umar Tijjani , Smith Graham I. , McCauley Philip , Peters Winston J. , Langdon John D.
Published: March 2003

Although the pathogenesis of Warthin's tumour is not fully understood, it is generally thought that the tumour arises from heterotopic salivary ducts within pre‐existing lymphoid tissue. Prolonged nitric oxide (NO) production by the enzyme type 2 nitric oxide synthase (NOS2) has been implicated in the pathogenesis of many solid tumours, but not in Warthin's tumour. Since NO and NOS2 are known to be associated with p53, the immunohistochemical expression of both NOS2 and p53 was investigated in 23 cases of Warthin's tumour. Widespread diffuse cytoplasmic immunostaining for NOS2 was found in tumour epithelial cells of all 23 cases studied, and it was additionally expressed in normal salivary duct epithelium. p53 staining was localised to the nuclei of tumour epithelium in 16 cases, with a similar pattern of distribution to tumour NOS2 expression. A significant correlation was found between NOS2 and p53 staining in the tumours (P < 0.001). In contrast to NOS2, p53 was not expressed by normal salivary ductal cells in any of the cases studied. NOS2 is widely expressed by the tumour epithelium of Warthin's, and its association with p53 expression is discussed. The role of NO in the pathogenesis of Warthin's tumour remains to be established.
Deranged expression of the E‐cadherin/β‐catenin complex and the epidermal growth factor receptor in the clinical evolution and progression of oral squamous cell carcinomas
Authors: Bánkfalvi Agnes , Kraßort Melanie , Végh András , Felszeghy Endre , Piffkó Jozsef
Published: March 2003

Background: Deranged expression and function of the E‐cadherin/β‐catenin (E‐cad/β‐cat) complex and the epidermal growth factor receptor (EGFR) have been implicated in the development and progression of carcinomas.

Methods: To estimate the role of these molecules in oral cancer, we investigated 75 primary oral squamous cell carcinomas (OSCCs) with adjacent normal and/or dysplastic mucosa, 30 paired metastases and 12 recurrences by immunohistochemistry.

Results: All three molecules were constitutionally expressed in the basal/parabasal layers of tumour adjacent ‘normal’ epithelium, in contrast to a significant increase of EGFR and heterogeneous expression of E‐cad/β‐cat in dysplasia. In OSCCs, over‐expression of EGFR correlated significantly with lower tumour grade and poor prognosis, loss of E‐cad was a significant marker for shortened survival, reduced β‐cat staining was a predictive marker for lymph node metastasis.

Conclusions: There is a perturbance in intercellular adhesion molecules and EGFR expression/function in oral cancer with major clinical impact. E‐cad and β‐cat seem to inhibit EGFR to enhance the progression of OSCCs.
Transforming growth factor β1 (TGFβ1) expression in head and neck squamous cell carcinoma patients as related to prognosis
Authors: Logullo Angela F. , Nonogaki Suely , Miguel Roberto E. , Kowalski Luiz P. , Nishimoto Inês N. , Pasini Fátima S. , Federico Miriam H. H. , Brentani Ricardo R. , Brentani M. Mitzi
Published: March 2003

Background:  Transforming growth factor β1 (TGFβ1) is a negative growth regulator in keratinocytes, and in vitro studies lead to the concept that loss of TGFβ1 responsiveness is a critical step in epithelial carcinogenesis.

Objective:  To investigate the prognostic relevance of TGFβ1 expression in head and neck squamous cell carcinoma (HNSCC).

Materials and methods:  TGFβ1 distribution was determined by immunohistochemistry in oral cavity/oropharynx (n = 79), larynx (n = 36) and hypopharynx (n = 25) tumors and in matched normal adjacent mucosa. TGFβ‐type I and II receptors were determined in 20 cases of differentiated oral cavity/hypopharynx tumors. Cases were considered positive if displaying reactivity in >10% of the cells.

Results:  TGFβ1‐positive expression was found in 47.2% of larynx, 36.7% of oral cavity/oropharynx and in 24% of the hypopharynx tumors. Reactivity in >60% of the cells was displayed only by 11.4% of HNSCC. All normal controls were positive. TGFβ1‐positive expression did not correlate with clinico pathological parameters. An association with differentiation was verified only in oral cavity/oropharynx tumors (P ≤ 0.001). TGFβ1 was also not related to 5 years survival (Kaplan–Meier). Strong and diffuse expression of TGFβ‐RII was identified in 19/20 cases regardless of TGFβ1 immunoreactivity. Out of 17 TGFβ1‐positive oral cavity/oropharynx tumors, only nine expressed TGFβ‐RI suggesting a disruption of the TGFβ1 pathway. We conclude that TGFβ1 protein immunostaining is not a useful biomarker in assessment of prognosis in HNSCC.
Nests and Nesting Materials: Aspects of the Realism of La gaviota
Authors: Larsen Kevin S.
Published: March 2003

Cecila Böhl de Faber (Fernán Caballero) figures as a proto‐Realist in the context of nineteenth‐century letters, but also incorporates aspects of the traditional Spanish realism and costumbrismo into La gaviota (1849). This novel becomes a veritable intertextual gallery, in which Cervantes and Don Quijote have a crucial, albeit often ironic, position. She also incorporates much folkloric material into her text: prominent is the story of “Medio‐pollito,” whose characters parallel and even explicate those in the larger narrative. This and other inclusions highlight her understanding of mimesis and verisimilitude, of the fictive and the “real.” Numerous writers have pointed out how the novelist was particularly conflicted about her protagonist, Marisalada. This ambivalence carries over into her narratological framework and role as an artist, for doña Cecilia confronts what has been termed the “anxiety of authorship” experienced by women writers in the nineteenth century. In La gaviota– no matter what gender, genre, or genealogy the author may invoke – one can document her belief that “la novela no se inventa, se observa,” as well as her efforts to “poetizar la realidad.” Likewise, Fernán Caballero is able creatively to “realizar la poesía” and “observar la invención.”
Possible Involvement of ERK 1/2 in UVA‐Induced Melanogenesis in Cultured Normal Human Epidermal Melanocytes
Authors: YANASE HIROSHI , ANDO HIDEYA , HORIKAWA MIWA , WATANABE MASAMI , MORI TOSHIO , MATSUDA NAOKI
Published: March 2003

UV‐induced melanogenesis is a well known physiological response of human skin exposed to solar radiation; however, the signaling molecules involved in the stimulation of melanogenesis in melanocytes following UV exposure remain unclear. In this study we induced melanogenesis in vitro in normal human epidermal melanocytes using a single irradiation with UVA at 1 kJ/m2 and examined the potential involvement of mitogen‐activated protein kinases (MAPK) as UVA‐responsive signaling molecules in those cells. UVA irradiation did not affect the proliferation of melanocytes, but it did increase tyrosinase mRNA expression, which reached a maximum level 4 hr after UVA irradiation. The amount of tyrosinase protein, as quantitated by immunoblotting, was also increased at 24 hr following UVA irradiation. Among the MAPK examined, extracellular signal‐related kinase (ERK) 1/2 was phosphorylated within 15 min of UVA irradiation, but no such phosphorylation was observed for c‐Jun N‐terminal kinases (JNK) or p38. Accordingly, the activity of ERK1/2 was also increased shortly after UVA irradiation. These responses of ERK1/2 to UVA irradiation were markedly inhibited when cells were pre‐treated with N‐acetyl‐l‐cysteine, an antioxidant, or with suramin, a tyrosine kinase receptor inhibitor. The formation of (6‐4)photoproducts or cyclobutane pyrimidine dimers was not detected in cellular DNA after UVA irradiation. These findings suggest that a single UVA irradiation‐induced melanogenesis is associated with the activation of ERK1/2 by upstream signals that originate from reactive oxygen species or from activated tyrosine kinase receptors, but not from damaged DNA.
A Polymorphism Study of the Human Agouti Gene and its Association with MC1R
Authors: Voisey Joanne , Box Neil F. , Van Daal Angela
Published: March 2003

To determine whether the Agouti Signalling Protein (ASP) gene is associated with skin and hair coloration in humans, the complete coding region of ASP was screened for polymorphisms. Analysis of ASP in Caucasian, African‐American, Spanish Basque, Hispanic, Apache and Australian Aboriginal populations revealed no amino acid substitutions. A single polymorphism in the 3′ untranslated region occurred at a frequency of 0.2 in African‐Americans. Variants of the Melanocortin 1 Receptor (MC1R) gene have been found to be associated with red hair and fair skin in humans. Red hair individuals are usually compound heterozygotes or homozygous for one of a number of MC1R polymorphisms associated with red hair. Some individuals however are heterozygous for only one of these polymorphisms and dizygotic twins can be concordant for MC1R variants but discordant for hair colour. A recent study has also identified rare redheads carrying no MC1R variants indicating that polymorphisms of the human MC1R gene are required but not sufficient for the red hair phenotype. To address the question of whether ASP also contributes to the red hair phenotype, individuals previously identified as having unexpected MC1R genotypes were screened for polymorphisms at the ASP locus. No polymorphisms were found in any of these individuals. Results indicate that the human ASP gene is unlikely to function in normal human pigmentation in the same way as MC1R.
The Expression of Corticotropin‐Releasing Hormone in Melanoma
Authors: Sato Hirofumi , Nagashima Yoji , Chrousos George P. , Ichihashi Masamitsu , Funasaka Yoko
Published: March 2003

We previously demonstrated that advanced melanoma cells express high amounts of proopiomelanocortin (POMC) that correlate with tumor progression. We now investigated whether the high expression of POMC derives from increased expression of corticotropin‐releasing hormone (CRH) and the possible role of CRH as a melanoma growth factor. Forty‐five cases of melanoma [25 primary malignant melanoma; 20 metastatic melanoma (MetM)] were immunohistochemically analysed for coexpression of POMC and CRH peptides. The ability of CRH to induce POMC expression in cultured melanoma cells was examined using CRH and a CRH antagonist. In CRH positive melanomas, seven out of nine cases (78%) of primary melanoma, and 7 out of 12 cases (58%) of MetM showed colocalization of CRH and POMC peptides. CRH induced POMC mRNA expression, an effect that was inhibited by a CRH antagonist. These results provide evidence for the existence of the CRH/POMC axis in pigmented lesions.
The Effect of Preparation Procedures on the Morphology of Melanin from the Ink Sac of Sepia officinalis
Authors: Liu Yan , Simon John D.
Published: March 2003

The structure of melanin extracted from the ink sac of the cuttlefish Sepia officinalis was examined for different methods of isolation and purification of the pigment. Scanning electron microscopy (SEM) images of Sepia eumelanin prepared by different procedures establish that multi‐μm‐sized aggregates reported by previous workers are generated by their sample preparation, and that the dominant constituents of Sepia melanin are ∼150 nm spherical granules. Brunauer‐Emmett‐Teller (BET) measurements reveal that Sepia eumelanin from Sigma (prepared by spray drying the pigment) has a surface area of 14.3 m2/g. Pigment extracted directly from the fresh ink sac and then freeze‐dried has a surface area of 21.5 m2/g, while CO2‐supercritically dried has a surface area of 37.5 m2/g. This is consistent with SEM images showing that the process of freeze‐drying produces aggregates, but to a lesser extent than spray drying. Supercritical drying of the sample produces suspensions of the individual ∼150 nm granule, which is more reflective of the natural pigment. Brunauer‐Emmett‐Teller surface area analysis and Barrett‐Joyner‐Halenda (BJH) pore volume analysis indicate that the surface of the granules is not smooth and the interior of the granules is not porous, but rather the aggregates of granules are porous. Ultra‐high resolution SEM and atomic force microscopy (AFM) images show the granules are easily deformed and are comprised of smaller constituents. De‐aggregation of the granules by sonication and ultra‐filtration reveal a range of structures depending on the pore size of the membrane used. The implications of these results on quantifying photochemical properties and kinetic reaction rate constants of melanin are discussed.
Effects of locally‐delivered human macrophage products and estrogen on murine inflammatory bone resorption
Authors: Crump T. B. , Wimmer K. L. , Reinhardt A. L. , Schmid M. J. , Meyer C. R. , Robinson D. H. , Marx D. B. , Bhattacharyya I. , Reinhardt R. A.
Published: March 2003

The objective of this study was to use an in vivo model of jreiodontitis (mouse calvaria) to quantify the effects of local release of secreted human macrophage products, 17β‐estradiol (E2), and proinflammatory lipopolysaccharide (LPS) on histologic bone resorption. Human THP‐1 monocytes (106) were converted to macrophage phenotype by 500 ng/ml phorbol 12‐myristate‐13‐acetate (PMA) and treated as follows: no stimulation or Escherichia coli LPS (10 µg/ml) alone or in combination with a physiologic dose of E2 (100 pg/ml) for 24 h in RPMI/10% FBS, washed extensively, then incubated for 24 h in serum‐free media. Sujrenatant products were concentrated and incorporated into a 4% (w/v) methylcellulose gel. Separate gels were incorporated with the following: LPS (500 µg/animal) alone, high dose of E2 (10 ng/animal) alone, a combination of LPS+E2, or gel only (controls). Loaded or control gels were placed into a polylactic acid occlusive dome, inserted subcutaneously over the calvaria of mature ovariectomized ICR Swiss mice (8 mice×7 groups×2 times [5/14 days] = 112 animals), then calvaria were evaluated histologically. Macrophage stimulation with LPS alone, but not LPS in combination with E2, produced sujrenatants which upregulated osteoclast numbers in the suture area compared to gel controls at 5 days (p = 0.009). The addition of LPS directly to the local delivery gels significantly upregulated osteoclasts in endosteal surfaces compared to gel controls at 5 days (p = 0.024) and at 14 days (p = 0.025). The addition of E2 to LPS down‐regulated resorption to a level not different from gel controls at 14 days. This in vivo model appears effective in studying inflammatory bone resorption, which may be inhibited by E2 directly or through its influence on secreted macrophage products.
Gingival recession defects and guided tissue regeneration: a review
Authors: Danesh‐Meyer Michael J. , Wikesjö Ulf M.E.
Published: March 2003

The last decade has seen an increasing number of clinical reports on guided tissue regeneration (GTR) for reconstruction of gingival recession defects. This article reviews the value of GTR in the management of gingival recession defects based on records from such reports. Studies and case‐series using nonresorbable and bioresorbable membranes, studies comparing GTR to the subepithelial connective tissue graft (CTG) procedure, and histologic reports of healing following GTR, published in the English language from 1985 to 2000, were identified using a Medline search and were included in the data‐base for this review. The following pre‐ and post‐treatment data were collated and evaluated for each of the reports: gingival recession depth, probing depth, clinical attachment level, and width of the keratinized gingiva. In perspective of the limitations of the studies reviewed, it has been shown that GTR may be used for reconstruction of gingival recession defects. Importantly, it has not been shown that GTR provides an added clinical benefit for the patient treatment planned for reconstruction of gingival recession defects, i.e. GTR does not appear to offer a significant advantage over mucogingival procedures such as the connective tissue graft or the advanced flap procedure. It is imperative to recognize inherent technical difficulties associated with GTR including primary wound closure and secondary membrane exposure; membrane exposures being negatively correlated to desired clinical outcomes. Also, membrane exposures appear consistently more common in smokers than in non‐smokers. It is also imperative to recognize shortcomings and adverse effects including space maintenance and unacceptable foreign body reactions associated with some bioresorbable GTR technologies.
Interaction of human salivary mucin MG2, its recombinant N‐terminal region and a synthetic peptide with Actinobacillus actinomycetemcomitans
Authors: Liu Bing , Rayment Sean A. , Soares Rodrigo V. , Oppenheim Frank G. , Offner Gwynneth D. , Fives‐Taylor Paula , Troxler Robert F.
Published: March 2003

The antimicrobial properties of human salivary mucin MG2 against the periodontal pathogen, Actinobacillus actinomycetemcomitans (A. actinomycetemcomitans), were investigated using purified MG2, rNMUC7 (a recombinant polypeptide containing residue 1–144 of MG2) and synthetic peptides PEP1 (residue 1–17) and PEP2 (residue 47–63). MG2 and rNMUC7 bound to A. actinomycetemcomitans strains SUNY75, SUNY465, SUNY523, 652 and JP2 in a liquid phase binding assay. The bactericidal activities of rNMUC7, PEP1 and PEP2 against A. actinomycetemcomitans SUNY523 were examined in a colony forming unit killing assay. The LD50 for rNMUC7 was 9 µM, for PEP2 was 20 µM and PEP1 did not exhibit bactericidal activity. The primary structure of these polypeptides was analyzed and a direct relationship between net positive charge and bactericidal activity was found. Screening of saliva samples from 60 individuals on Western blots probed with an anti‐MG2 antibody against PEP2 revealed that a 20 kDa MG2 fragment was present in 66% of subjects and that this fragment was not present in glandular secretions. Matrix‐assisted laser desorption ionization time‐of‐flight mass spectrometry of tryptic peptides derived from the 20 kDa fragment confirmed that this fragment contained a portion of the amino terminal region of MG2. The present study showed that the N‐terminal region of MG2 and a subdomain within this region are microbicidal against A. actinomycetemcomitans and that a 20 kDa fragment of MG2 occurs in whole saliva. This suggests that cleavage of MG2 in vivo may produce fragments with microbicidal properties and that this may represent a novel mechanism of host defense.
Cytokine regulation of syndecan‐1 and ‐2 gene expression in human periodontal fibroblasts and osteoblasts
Authors: Worapamorn W. , Tam S. P. , Li H. , Haase H. R. , Bartold P. M.
Published: March 2003

Cell‐surface proteoglycans participate in several biological functions including interactions with a variety of growth factors and cytokines. Regulation of syndecan‐1 and ‐2 gene expression was investigated in human periodontal ligament fibroblasts (PDLF), osteoblasts (OB) and gingival fibroblasts (GF), in response to platelet‐derived growth factor (PDGF‐BB), transforming growth factor (TGF‐β1), and interleukin (IL‐1β) by Northern blot analyses. We also compared the effect of PDGF‐BB and TGF‐β1, separately and in combination, in the prolonged presence of IL‐1β on the expression of both syndecan genes. The results demonstrated that the three cell lines regulated the expression of syndecan‐1 and ‐2 in response to growth factors and cytokines in different manners. These cell lines increased syndecan‐1 mRNA levels in response to either PDGF‐BB or TGF‐β1 and decreased levels in response to IL‐1β. The effect of IL‐1β on syndecan‐1 mRNA synthesis was partially reversed after adding PDGF‐BB and TGF‐β1, separately or in combination, in the presence of IL‐1β. In contrast, syndecan‐2 mRNA level was markedly upregulated in response to either TGF‐β1 or IL‐1β in OB when compared with the other two cell lines. However, the stimulatory effect of TGF‐β1 on syndecan‐2 mRNA production in OB was abolished in the prolonged presence of IL‐1β. These findings lend support to the notion that syndecan‐1 and syndecan‐2 have distinct functions which correlate with their source and functions within the periodontium.
Recombinant human basic fibroblast growth factor (bFGF) stimulates periodontal regeneration in class II furcation defects created in beagle dogs
Authors: Murakami S. , Takayama S. , Kitamura M. , Shimabukuro Y. , Yanagi K. , Ikezawa K. , Saho T. , Nozaki T. , Okada H.
Published: March 2003

Several growth factors (or cytokines) have been recently investigated for their use as potential therapeutics for periodontal tissue regeneration. The objective of this study was to evaluate periodontal tissue regeneration, including new bone and cementum formation, following topical application of recombinant basic fibroblast growth factor (bFGF, FGF‐2) to furcation class II defects. Twelve furcation class II bone defects were surgically created in six beagle dogs, then recombinant bFGF (30 µg/site) + gelatinous carrier was topically applied to the bony defects. Six weeks after application, periodontal regeneration was analyzed. In all sites where bFGF was applied, periodontal ligament formation with new cementum deposits and new bone formation was observed histomorphometrically, in amounts greater than in the control sites. Basic FGF‐applied sites exhibited significant regeneration as represented by the new bone formation rate (NBR) (83.6 ± 14.3%), new trabecular bone formation rate (NTBR) (44.1 ± 9.5%), and new cementum formation rate (NCR) (97.0 ± 7.5%). In contrast, in the carrier‐only sites, the NBR, NTBR, and NCR were 35.4 ± 8.9%, 16.6 ± 6.2%, and 37.2 ± 15.1%, respectively. Moreover, no instances of epithelial down growth, ankylosis, or root resorption were observed in the bFGF‐applied sites examined. The present results indicate that topical application of bFGF can enhance considerable periodontal regeneration in artificially created furcation class II bone defects of beagle dogs.