bluuebunny/crossref_metadata_2025 huggingface dataset:
Protein expression of double‐stranded RNA‐activated protein kinase (PKR) in intrahepatic bile ducts in normal adult livers, fetal livers, primary biliary cirrhosis, hepatolithiasis and intrahepatic cholangiocarcinoma
Authors: Terada Tadashi , Ueyama Junichi , Ukita Yoko , Ohta Tetsuo
Published: March 2003

Abstract: Background/Aim: The protein expression of double‐stranded
RNA‐activated protein kinase (PKR) in intrahepatic bile ducts has not been investigated. Methods: Immunohistochemistry and a semiquantitative scoring method in normal liver and biliary diseases were used for the investigation. Results: In “normal” adult livers (n=10), intrahepatic bile ducts were negative for PKR. In normal fetal livers (n=25), primitive biliary epithelia were almost negative for PKR. In primary biliary cirrhosis (PBC) (n=30), damaged bile ducts were frequently positive for PKR, while uninvolved bile ducts were negative. In hepatolithiasis (n=27), proliferated bile ducts were positive for PKR, and the PKR score correlated with the degree of proliferation. In cholangiocarcinoma (CC) (n=44), PKR expression was frequently noted, and the PKR score correlated with good differentiation of CC, being highest in well‐differentiated CC and lowest in poorly‐differentiated CC. The PKR score decreased in the following order: CC (mean PKR score=3.96), hepatolithiasis (2.56), PBC (1.60), normal fetal liver (0.40), and normal adult livers (0.00). The PKR expression in hepatocytes was “baseline” in normal adult livers, while moderately increased in fetal livers, PBC, hepatolithiasis and CC. Conclusions: Although the significance of these data is unclear, they suggest (i) that PKR is absent in bile ducts in normal adult and fetal livers, (ii) that PKR in bile duct cells newly emerges or increases in PBC, hepatolithiasis, and CC, (iii) that PKR accumulates in damaged bile ducts in PBC, (iv) that PKR increases in parallel with biliary cell proliferation in hepatolithiasis, and (v) that PKR expression correlates with differentiation in CC. PKR expression in intrahepatic bile ducts seems to be associated with inflammation or cell proliferation of the bile duct cells.
Colchicine for alcoholic and non‐alcoholic liver fibrosis or cirrhosis
Authors: Rambaldi Andrea , Gluud Christian
Published: March 2003

Abstract: Aims/Background: Colchicine is an anti‐inflammatory and anti‐fibrotic drug. Several randomized clinical trials have addressed the question whether colchicine has any efficacy in patients with alcoholic as well as non‐alcoholic fibrosis and cirrhosis. The objectives were to assess the efficacy of colchicine evaluated in randomized trials on mortality, liver related mortality, liver related complications, liver fibrosis markers, liver histology, alcohol consumption, quality of life, and health economics in patients with alcoholic and non‐alcoholic fibrosis or cirrhosis. Methods: Interventions encompassed peroral colchicine at any dose versus placebo or no intervention. The trials could be double‐blind, single‐blind or unblinded. The trials could be unpublished or published as an article, an abstract, or a letter, and no language limitations were applied. All analyses were performed according to the intention‐to‐treat method. MEDLINE, The Cochrane Controlled Trials Register, The Cochrane Hepato‐Biliary Group Controlled Trials Register and full text searches were combined. Results: Combining the results of 14 randomized clinical trials including 1138 patients demonstrated no significant effects of colchicine on mortality (odds ratio (OR): 0.91; 95% confidence interval (CI) 0.64, 1.31), liver related mortality (OR: 0.98; CI 0.56, 1.74), complications (OR: 1.06; CI 0.65, 1.73), and the other outcomes. Colchicine was associated with a significantly increased risk of adverse events (OR: 4.41; CI 2.24, 8.70; p< 0.001). Conclusions: Colchicine should not be used for liver fibrosis or liver cirrhosis irrespective of etiology. Future trials on colchicine for liver diseases ought to be large.
Insulin‐like growth factor‐I restores the reduced somatostatinergic tone controlling growth hormone secretion in cirrhotic rats
Authors: Castilla‐Cortázar Inma , Aliaga‐Montilla M. Aurelia , Salvador Javier , García María , Delgado Gloria , González‐Barón Salvador , Quiroga Jorge , Prieto Jesús
Published: March 2003

Abstract: Background/Aims: An altered growth hormone/insulin‐like growth factor‐I (GH/IGF‐I) axis occurs in advanced liver cirrhosis, characterised by diminished serum levels of IGF‐I and increased concentrations of GH. Under normal conditions, GH release is mediated by somatostatin (SS) inhibition. However, the influence of SS on GH release in cirrhosis is not well known. IGF‐I supplementation has beneficial effects in experimental cirrhosis, and – under physiological conditions – IGF‐I increases SS, inhibiting GH. The aims of this work were to study SS tone in cirrhotic animals and to evaluate whether IGF‐I treatment influences SS tone, controlling GH secretion in cirrhosis. Methods: We studied the influence of SS on GH secretion by assessing GH response to pyridostigmine (PD) in cirrhotic rats treated and untreated with IGF‐I. Liver cirrhosis was induced with CCl4‐inhalation for 11 weeks in male Wistar rats. The animals were randomly divided into two groups: CI+IGF (n=12), which received IGF‐I treatment for 12 days (2 μg/100 g body wt−1×d−1) and CI (n=12), which received saline. Healthy controls (CO, n=12) were studied at the same time. On day 13, animals from each group were subdivided into two groups (n=6) in order to explore the effect of a PD intrajugular bolus (10 μg×100 gbw−1) on serum GH levels (at 0,10,20,30 and 60 min), which were assessed by RIA. Results: PD bolus did not exert any effect on GH serum levels in the CI group, suggesting a low SS tone in cirrhotic rats. However, PD induced an increase in GH levels into CO and CI+IGF groups. In conclusion, as occurs under normal conditions, the cholinergic system is a significant modulator of GH secretion in experimental liver cirrhosis. Conclusion: Cirrhotic rats have a reduced somatostatinergic tone which can be restored by IGF‐I supplementation, suggesting that somatostatin is the main factor involved in the feed‐back regulation between GH and IGF‐I in cirrhosis.
Des‐gamma‐carboxy prothrombin (DCP) ratio, a novel parameter measured by monoclonal antibodies MU‐3 and 19B7, as a new prognostic indicator for hepatocellular carcinoma
Authors: Sugimoto Hiroyuki , Takeda Shin , Inoue Soichiro , Kaneko Tetsuya , Watanabe Keisuke , Nakao Akimasa
Published: March 2003

Abstract: Background/Aim:  Recently, a novel des‐gamma‐carboxy prothrombin (DCP) antibody named 19B7 has been developed. It has been reported that the DCP ratio defined by DCP measured by MU‐3 antibody/DCP measured by 19B7 antibody demonstrated differences between hepatocellular carcinoma and vitamin K deficiency. The aim of this study was to clarify the relationship between the DCP ratio and tumour malignancy, as well as the prognostic significance of the DCP ratio after hepatectomy for hepatocellular carcinoma. Methods: From January 1996 to December 1999, 79 patients diagnosed with hepatocellular carcinoma underwent hepatectomy. To detect DCP in the plasma before surgery, we used a new EIA kit, Eitest PIVKA‐II kit (Eisai, Tokyo, Japan) with both MU‐3 and 19B7 antibody. The DCP ratio was calculated using the formula: DCP ratio = DCP level measured by MU‐3 antibody (mAU/ml)/DCP level measured by 19B7 antibody (mAU/ml). Pathologic findings using resected specimens were classified according to the Japanese General Rules for Primary Liver Cancer. Results: Among DCP‐positive patients, the DCP ratio was significantly higher in those with tumour thrombus in the portal vein (vp) or with a moderately or poorly differentiated hepatocellular carcinoma than in those without vp or with a well‐differentiated carcinoma (P = 0.0162, 0.0109, respectively). Patients with DCP ratio > 3 had a significantly higher incidence of vp than those with DCP ratio ≤ 3 (P = 0.0027). The survival rate was significantly higher in patients with DCP ratio ≤ 3 than in those with DCP ratio > 3 (P = 0.0002). This result was the same as in DCP positive cases (P = 0.0027). Conclusions: The DCP ratio can distinguish DCP produced by hepatoma cells from DCP produced by normal hepatocytes in vitamin K deficiency. The DCP ratio is a useful prognostic indicator that can be assessed before hepatectomy.
A new critical assessment of the copper‐lead system
Authors: Onderka B. , Zabdyr L. A.
Published: March 2003

New experimental information was added to previous assessment data, and optimisation was carried out for the liquid and both fcc phases. Phase‐diagram calculations resulted in new invariant reaction parameters and coordinates of phase boundaries. They were compared to results of previous evaluations and to experimental data as well. It is concluded, that results of calculations better describe the system than uncertain experimental data.
Slag formation and its role in the ferrochromium production
Authors: Jansson Åke , Brabie Voicu , Fabo Endre , Jansson Sune
Published: March 2003

The aim of the present investigations was to get a better understanding of the mechanism of the chromite reduction in the submerged‐arc furnace and to evaluate the role of slag formation on reduction kinetics and electrode consumption. The reduction behaviour of three natural chromite ores was therefore studied at a temperature range between 1273 K and 1873 K. The reduction was by coke in the presence of silica. The composition of the chromite ores and the gangue minerals affects reduction behaviour and electrode consumption. To decrease electrode consumption a careful adjustment of slag composition and prevention of early slag formation are recommended.
Dilatation analysis of the eutectoid transformation of the as‐cast spheroidal graphite cast iron
Authors: Mrvar Primoz , Trbizan Milan , Medved Jozef
Published: March 2003

It is known that the decomposition of austenite in spheroidal graphite cast iron (SGI) depends on numerous factors. Among them, the cooling rate and microsegregation of alloying elements (Si, Cu, Mn) are derived from the solidification step. The eutectoid transformation of the SGI has been investigated with a new dilatometer that was made for the investigation of cast iron alloys. The temperature dependence of the dilatations, similar to a function of time is shown by the dilatation curves. The investigation of the eutectoid transformation has been examined by the evaluation of dilatation curves, metallographic examinations and chemical compositions. It is possible to exactly follow the eutectoid transformation of austenite, which proceeds according to the stable reaction in ferrite and graphite (γ→α+ graphite), the metastable reaction in perlite (γ→α+ Fe3C), or dilatometric and differential dilatometric curves, respectively. The ratio between the perlite and ferrite phase in the matrix of the spheroidal graphite cast iron depends upon the extent of each reaction. The temperature difference between the dilatation extremes during the eutectoid reactions, as a function of the ferrite fraction, has been determined. A correlation between the amount of ferrite and the characteristic expansion owing to the graphite precipitation was found.
Practical and theoretical aspects of hot rolling of flat products
Authors: Siwecki Tadeusz , Engberg Göran , Hansson Per
Published: March 2003

Knowledge of microstructure development in association with hot rolling is very important for optimizing rolling schedules with the aim of improving properties of steels in the as‐hot‐rolled condition. Computer models for calculation of the microstructure evolution (grain size, grain growth, precipitation and flow stress) during heavy plate and strip hot rolling are invaluable for design of rolling schedules combining a maximum degree of microstructural refinement with acceptably low rolling loads. Intelligent design of deformation/temperature schedules aims to generate an optimal austenite microstructure and subsequently a fine ferrite/bainite conferring both toughness and strength. A brief survey of the models developed in Sweden and particularly at the Swedish Institute for Metals Research and used by the Swedish Steel Industry is made. The models can be used for predictions of recrystallization and grain growth of austenite after deformation, precipitation or dissolution of microalloying carbonitrides in austenite, flow stress during hot working, phase transformation behaviour during accelerated cooling (ACC) as well as the final microstructure and mechanical properties. The effects of the hot rolling process parameters are discussed in relation to the microstructure and mechanical properties of high‐strength steels, microalloyed with Ti, V, (Mo) and/or Nb. A comparison of the results of laboratory simulations with full‐scale industrial plate, strip and long product processing using hot rolling practices obtained at various (high and low) finish rolling temperatures with and without the application of ACC/direct quenching is made.
Activity of phosphorus in liquid cobalt‐phosphorus alloys in equilibrium with solid cobalt
Authors: Hasegawa M. , Iwase M. , McLean A.
Published: March 2003

Electrochemical measurements involving stabilized zirconia as a solid electrolyte were conducted in order to determine the activities of phosphorus in liquid {Co‐P} alloys in equilibrium with solid cobalt at temperatures between 1573 and 1693 K. By using the present data for the two‐phase region of Co(s) + {Co‐P}(l), the free energy for the solution of diatomic gaseous phosphorus in pure liquid cobalt at 1 wt% solution was derived as:
Numerical study of the pusher‐type slab reheating furnace
Authors: Mäki Anne Marketta , Österman Pekka Juhani , Luomala Matti Juhani
Published: March 2003

In the present work, a commercial computational fluid dynamics (CFD) software package, PHOENICS, was used in order to develop three‐dimensional model of pusher‐type slab reheating furnace. The purpose was to gain knowledge of gas flows and temperature distribution in the furnace. The burners were first modelled as hot gas jets, and later the accuracy of the model was improved with the implementation of the eddy‐break‐up (EBU) reaction model. In the model with the reactions, the flow velocities were slightly slower through the whole furnace area, and the temperature in the charge end of the furnace was considerably higher. The differences between the two cases were compared and the reason for their occurrence was discussed. Furthermore, two turbulence models, k‐ε and RNG (renormalization group), were tested. The biggest differences appear in the lower heating zone, where the recirculation zones have different shapes, and the kinetic energy of turbulence is much lower with the RNG model than with the k‐ε model.
A thermodynamic assessment of the Fe‐Gd‐Mo system
Authors: Zinkevich Matvei , Mattern Norbert , Seifert Hans‐Jürgen , Gmelin Eberhard
Published: March 2003

Certain ternary intermetallic compounds formed between rare‐earth and transition metals are of particular interest, since their high saturation magnetization and strong, uniaxial, magnetocrystalline anisotropy are of advantage for the practical applications as permanent magnets. The thermodynamics of the Fe‐Gd‐Mo system are assessed based on phase‐diagram information and the heat capacity data. The Fe‐Gd description was modified to account for the experimentally‐observed ternary phase equilibria involving binary phases. The assessment was done using a multi‐component thermodynamic software Thermo‐Calc. The assessment of the Fe‐Gd‐Mo ternary system shows reasonable agreement with the available experimental data. The calculated projection of the monovariant liquidus lines qualitatively reproduces the experimental one. The calculated isothermal sections are in general agreement with the experimental observations. However, the assessment can be improved with more data regarding the solidification behaviour and the magnetic properties of intermetallic phases.
Resource specialization determines whether history influences community structure
Authors: Long Zachary T. , Karel Irene
Published: March 2003

History, specifically the sequence of species arrival, can affect community composition. Tests for a locally operating mechanism that can produce this result remain rare. Here we show how interspecific competition for resources combined with history can produce different communities. Specifically, history should influence community structure much less when all competitors use the same resource base than when some resources are unavailable to some competitors. We manipulated the resources available to competing ciliates in aquatic microcosms to test this hypothesis. We created communities that had only bacteria, or both bacteria and algae as consumable resources. When only bacteria were available, the best competitor, Colpidium striatum, always dominated regardless of differences in colonization history. History did affect the densities of competitively equivalent subordinate species, Paramecium tetraurelia and P. caudatum. The least effective competitor, Tetrahymena thermophila, went extinct in almost every community. P. tetraurelia and P. caudatum can also consume algae in addition to bacteria. History had a much larger effect in communities where both bacteria and algae were available as resources. In these communities, the initially dominant species always maintained dominance throughout the experiment, with the exception of T. thermophila which still went extinct. The experiment lasted for over 30 generations of the dominant species, so all effects of history persisted over ecologically important time scales.
Unconventional bed mates: Gaia and the selfish gene
Authors: Dagg Joachim L.
Published: March 2003

In this forum, David M. Wilkinson argued that Gaia‐type phenomena can be explained by conventional ecological ideas meaning that such phenomena do not require major changes to existing ecological or evolutionary theory. Overstating my case a little, I will argue that a reconciliation between Gaia and Darwinism will not be conventional in the sense of mainstream ecology. The main addition of this essay is an exploration in how far the claim that the atmosphere is an extension of life on Earth is logically correct. In a thought experiment, the idea of extended phenotypes by Richard Dawkins can be integrated with the one of Gaia. The problem of cheats remains pertinent, however, because the atmosphere will not select differentially between cheats and non‐cheats. Conclusion: Gaia‐type phenomena will be by‐products of naturally selected traits. As such they are not jeopardised by cheats, because side effects can be free to self‐organise, while the main effects will be naturally selected for evolutionarily stable states. Understanding the laws of self‐organisation of such side effects will be of major importance to all environmental sciences.
Do kleptoparasites reduce their own foraging effort in order to detect kleptoparasitic opportunities?: An empirical test of a key assumption of kleptoparasitic models
Authors: Smith Rik D. , Ruxton Graeme D. , Cresswell Will
Published: March 2003

Determining if, or when, individuals trade off time spent personally feeding against time spent monitoring others for kleptoparasitism opportunities is essential to an understanding of the evolution of scrounging and usurpation behaviours. We provide a first field test of whether kleptoparasites reduce their personal foraging effort in situations where the frequency and rewards of kleptoparasitism increase. We provided experimental food patches for wild European blackbirds that varied in the distribution of prey and that had a potentially high rate of kleptoparasitism within pairs of blackbirds feeding in them. Although individuals differed in their rate of kleptoparasitism, they did not vary in the size of the reward that they gained from kleptoparasitism. As prey became more clumped, kleptoparasitism rate and its reward per incident increased on average. There was, however, no evidence that individuals that were kleptoparasitising more quickly and/or at a higher frequency had lower personal foraging effort. In contrast, foraging effort increased in both birds compared to when they were foraging alone, independent of dominance, kleptoparasitic opportunity or reward. Our evidence suggests that in some circumstances a kleptoparasite can detect kleptoparasitic opportunities without compromising its own personal foraging rate.
Consequences of the interaction between nutrients and plant secondary metabolites on herbivore selectivity: benefits or detriments for plants?
Authors: Villalba Juan J. , Provenza Frederick D. , Bryant J. P.
Published: March 2003

Concentrations of nutrients and plant secondary metabolites (PSM) vary temporally and spatially, creating a multidimensional feeding environment. Interactions between nutrients and PSM are poorly understood because research has relied largely on studying the isolated effects of nutrients or PSM on foraging behavior. Nevertheless, their interactions can influence food selection and the dynamics of plant communities. Our objective was to explore how interactions between nutrients and PSM influence food selection. For 7 d, three groups of lambs received intraruminal infusions of three different doses of a PSM (0=Control; low and high) and 2 h later they were offered two foods that contained either low (high in energy) or high (high in protein) protein/energy ratios. The foods were offered 7 d before (baseline) and 7 d after PSM infusions. We conducted five trials each with a different PSM‐ terpenoids, cyanogenic glycosides, sodium nitrate, quebracho tannin, and lithium chloride. Lambs consistently preferred the food high in energy to the food high in protein, but toxins modified the degree to which this preference was manifest. Terpenoids, nitrate, and lithium chloride depressed intake of the food high in energy. Cyanogenic glycosides had the opposite effect, and at higher doses they depressed intake of the food high in protein. Tannins enhanced intake of the food high in energy at lower doses and they depressed its ingestion at higher doses. Thus, PSM selectively depressed or enhanced intake depending on the macronutrient composition of the foods. These results imply that the probability of a plant being eaten will depend not only on its chemical defenses but also on the quantity and quality of nutrients in the plant and its neighbors, and that the ability of herbivores to learn associations between nutrients and PSM may have a substantial impact on the way herbivores regulate ecosystem processes.
Specialist and generalist natural enemies as an explanation for geographical gradients in population cycles of northern herbivores
Authors: Klemola Tero , Tanhuanpää Miia , Korpimäki Erkki , Ruohomäki Kai
Published: March 2003

Within Fennoscandia, two well‐studied groups of herbivores exhibit clear geographical gradients in their population dynamics. Populations of a forest lepidopteran (Epirrita autumnata, the autumnal moth) and voles of the generaMicrotusandClethrionomysshow pronounced multi‐annual cycles in the north but become more stable towards the south. Here we review empirical and theoretical studies on these species, mainly regarding the biological mechanisms that are assumed to generate the pattern of population dynamics in both systems. We conclude that the specialist/generalist predation hypothesis offers a common explanation for the population cycles and their geographical gradients irrespective of whether a herbivorous insect or small mammals are concerned. According to this hypothesis, originally developed for the Fennoscandian voles, but now applied also toE. autumnata, population cycles are generated by specialist natural enemies (predators for the voles and parasitoids forE. autumnata). Furthermore, the dynamic shift from cycles to stability is assumed to be caused by an increase in the density and diversity of generalist natural enemies from north to south in Fennoscandia.
An anatomy of interactions among species in a seasonal world
Authors: Sandvik Gunnar , Seip Knut L. , Pleym Harald
Published: March 2003

Mathematical models merging biological and predictable seasonal dynamics were used to simulate four types of organism interactions: competition, prey‐predation, mutualism and facilitation. By analysing trajectories for biomass in phase portraits (i.e. species 1 biomass plotted against species 2 biomass) graphically and numerically, we found that each of the four interaction types showed characteristic patterns (“fingerprints”) in phase space. All the four interaction types could be distinguished, even though their time trajectories were strongly modified by seasonal forces. For each of the interaction types, we were able to identify characteristics of the interaction that most strongly distinguished it from the others. We could also assess the relative effect of species characteristics and seasonality on each of the four interactions. The simulations indicate that prey‐predation is strongly influenced by seasonal forces and by the characteristics of the predator and its prey. A system variability index got a high value (SVI)=0.167 relative to those of the other interaction types (competition 0.01, mutualism 0.007 and facilitation 0.005). The result was obtained by calculating, angles between successive vectors linking pairs of samples and the positive x‐axis and arranging these as frequency histograms for each of the four quadrants of the phase portrait. In an effort to capture circular motions and other characteristics of the trajectories sampled, angle frequencies were analysed using multivariate statistics (PCA), yielding “characteristic directions” in phase space. We believe that the characteristic patterns identified also will be found in real time series.
Disorder‐specific changes in innervation in oral lichen planus and lichenoid reactions
Authors: Niissalo Sirkku , Hietanen Jarkko , Malmström Maria , Hukkanen Mika , Polak Julia , Konttinen Yrjö T.
Published: March 2003

Abstract: The peripheral nervous system was analysed in the oral mucosa of eight patients with oral lichen planus (OLP), five with a lichenoid reaction (LR) and three with mild chronic inflammation (MCI), by morphometric analysis of nerve fibres containing immunoreactive PGP 9.5, substance P (SP), calcitonin gene‐related peptide (CGRP), vasoactive intestinal polypeptide (VIP), or C‐flanking peptide of neuropeptide Y (CPON). Overall nerve fibre density was higher in OLP (P=0.039) and LR (P=0.026) compared with healthy oral mucosa and was compatible with sprouting and collateral formation. In contrast to the innervation visualized with structural nerve fibre‐marker PGP 9.5, the densities of neuropeptide‐immunoreactive nerves were low in inflamed tissue. This is consistent with depletion via local release. Retraction and local loss of innervation were found in areas coinciding with the most severe inflammation and basal membrane (BM) damage. Interestingly, LR showed a twenty‐eight‐fold loss of post‐ganglionic CPON‐ir sympathetic nerve fibres (P=0.044). In LR, CPON‐ir innervation was markedly lower than in OLP. Finally, the pattern of innervation in relation to inflammatory cell infiltrates and tissue structures differed between OLP and LR. In conclusion, the peripheral nervous system is implicated in the immunopathogenesis of lichen planus and lichenoid reactions, with a disorder‐specific difference in this involvement.
TGF‐β isoforms and TGF‐β receptors in drug‐induced and hereditary gingival overgrowth
Authors: Wright Helen J. , Chapple Iain L. C. , Matthews John B.
Published: March 2003

Abstract: Drug therapy and hereditary factors are two of the main causes of gingival overgrowth (GO). Both of these forms of GO are associated with increased extracellular matrix production by fibroblasts. Transforming growth factor beta (TGF‐β) is an important mediator of wound healing and tissue regeneration, which stimulates fibroblasts to produce extracellular matrix materials. The aim of this immunohistochemical study was to determine whether there is any altered expression of TGF‐β isoforms or its receptors in tissue from patients with drug‐induced GO (DIGO; n=10) and hereditary gingival fibromatosis (n=10) when compared to non‐overgrowth tissue (n=10). Compared to control tissues, significantly more fibroblasts expressed TGF‐β1 in both DIGO and hereditary gingival fibromatosis tissues (P<0.03). Cells expressing TGF‐β2 were present at control levels in DIGO but were significantly reduced in hereditary gingival fibromatosis (P<0.02). By contrast, the number of TGF‐β3‐positive cells was the same in overgrowth tissues and controls. However, because of differences in total fibroblast densities between groups, there was a proportional increase in TGF‐β3 as well as TGF‐β1 expressing cells within both overgrowth populations (P<0.0001). Furthermore, representation of the TGF‐β2‐positive phenotype was reduced in hereditary gingival fibromatosis (P<0.01) but increased in DIGO (P<0.005) compared to controls. Absorbance measurements of the positive cell populations showed that the level of expression was significantly higher for TGF‐β1 in hereditary gingival fibromatosis (P<0.002) and significantly lower for TGF‐β3 in DIGO (P<0.03). No significant differences in the numbers of TGF‐βRI‐ or RII‐positive cells were detected between overgrowth tissues and controls. However, there were increases in the proportion of receptor‐positive cells in the total cell population analysed in overgrowth tissues (P<0.0001). These results indicate qualitative and quantitative differences in TGF‐β isoform and receptor expression by fibroblasts in gingival overgrowth that may contribute to disease pathogenesis.
Salivary albumin, total protein, IgA, IgG and IgM concentrations and occurrence of some periodontopathogens in HIV‐infected patients: a 2‐year follow‐up study
Authors: Mellanen Liisa , Sorsa Timo , Lähdevirta Juhani , Helenius Miia , Kari Kirsti , Meurman Jukka H.
Published: March 2003

Abstract: HIV infection reduces oral defensive mechanisms and may affect mucosal integrity. Differences in salivary protein concentrations and periodontopathogenic bacteria were studied in 56 HIV‐infected patients with respect to their disease phase. Thirty‐three patients were followed up for 2 years. Fifty‐three healthy subjects of corresponding age and sex were studied as controls. At baseline, salivary albumin, total protein, IgA, and IgM levels were significantly higher (P<0.05–0.0001) in all phases of HIV infection, except the asymptomatic (ASX) phase, when compared with the control group. IgG levels were significantly increased in all phases except the ASX phase (P<0.05). After 2 years, salivary total protein, IgG, and IgM levels were still higher (P<0.05–0.005) in all HIV phases when compared with the control group (P<0.05–0.005). The albumin level was significantly higher in the ASX phase (P<0.005) and in the AIDS‐related complex phase (ARC) (P<0.05), while the increase in IgA level was significant only in the ARC phase (P<0.005). Periodontopathogenic bacteria analyzed by PCR were detected both in the patients and the non‐infected, but a statistically significant difference in the carriage percentage between the follow‐up lymphadenopathy syndrome phase (LAS) and the control group was found only in Porphyromonas gingivalis (P<0.05) and Bacteroides forsythus (P< 0.0001). Thus, HIV infection appeared to cause a significant increase in the studied salivary proteins, suggesting leakage of serum components into the mouth.
The potential use of saliva to detect recurrence of disease in women with breast carcinoma
Authors: Bigler Lenora R. , Streckfus Charles F. , Copeland Lynn , Burns Rebecca , Dai Xiaoli , Kuhn Melinda , Martin Patricia , Bigler Steven A.
Published: March 2003

Background:  Approximately 1 woman in every 10 will develop breast cancer in her lifetime. It has been shown that screening for breast cancer can reduce breast cancer mortality. The use of a saliva‐based test could prove to be very useful in post‐operative and/or adjunctive therapy management of breast cancer patients.

Methods:  The following study was undertaken to establish the possible usefulness of the salivary protein product of the oncogene c‐erbB‐2 in following patients diagnosed with carcinoma of the breast. Included in this study were 25 patients with a mean age of 54 years with varying histological diagnoses and stages of carcinoma of the breast. ELISA assays for c‐erbB‐2 and CA 15–3 were performed on serum and stimulated whole saliva samples collected on all patients prior to any adjunct therapy or surgery and sequentially during therapy.

Results:  The results of the GLM analyses using marker concentration as the dependent variable and treatment regimen and the serial assessments as independent variables yielded a significant overall model for both the serum (P < 0.007) and salivary (P < 0.017) c‐erbB‐2 markers. The model for serum c‐erbB‐2, however, exhibited a significant difference for treatment regimen (P < 0.001) with the chemotherapy and radiation treatment regimen being significantly different (P < 0.001) from the other treatment therapies. Time (serial assessments) was not significant. The model for the salivary c‐erbB‐2 marker was reversed. Treatment regimen was not significant for this model; however, time (serial assessments) was significant (P < 0.002). The serum and salivary CA 15–3 marker models yielded no significant results. Paired t‐test analyses indicated that only the salivary c‐erbB‐2 concentrations exhibited a significant difference between the pre‐ and post‐therapy values (t = 4.245, P < 0.0001). Additionally, salivary c‐erbB‐2 displayed greater percent reductions across all therapies as compared to the other markers.

Conclusions:  This preliminary study appears to indicate that c‐erbB‐2 protein expression in saliva may be a very useful diagnostic tool for measuring patient response to chemotherapy and/or surgical treatment of their disease.
No developmental failure of cultured tooth germs from osteopetrotic (op/op) mice
Authors: Ida‐Yonemochi Hiroko , Saku Takashi
Published: March 2003

Background:  Incisor tooth germs of osteopetrotic (op/op) mice are known to fail to erupt, but form odontomas in their root apices instead, due to invasion of alveolar bone trabeculae into the tooth germs. The purpose of this study is to determine if the tooth developmental failures in op/op mice are intrinsic or secondarily arise as a result of the defective bone metabolism due to lack of macrophage colony‐stimulating factor (M‐CSF).

Methods:  We isolated mandibular first molar tooth germs from normal and op/op mice and cultured them under conditions with or without bone tissues which had been formed around tooth germs.

Results:  Tooth germs from normal mice, cultured for a week, showed almost the same developmental features as those of mice with the corresponding age. They were surrounded with dental follicular tissues and were never invaded by bone trabeculae. On the other hand, op/op tooth germs cultured in the presence of bone components were invaded by alveolar bone trabeculae around tooth germs in the same manner as shown in vivo. When cultured without bone, they developed without any interruptions.

Conclusions:  These findings indicated that op/op tooth germs had potential for normal development and that their abnormal development was a secondary phenomenon caused by lack of bone remodeling in the early phase of odontogenesis.
Uncommon dermoid cyst presented in the mandible possibly originating from embryonic epithelial remnants
Authors: Komiyama Kazuo , Miki Yukako , Oda Yasuyuki , Tachibana Tshihito , Okaue Masahiro , Tanaka Hiroshi , Moro Itaru
Published: March 2003

A case of an intraosseous dermoid cyst that had developed in the mandible of a 29‐year‐old‐male is reported. The patient was admitted to our dental clinic complaining of pain in the right molar area of the mandible. The patient had no particular history of the present illness. A radiographic examination revealed diffuse bone absorption in the right molar area. A biopsy showed the lesion to be an intraosseous dermoid cyst which was surgically enucleated. Microscopic examination of the excised tissue showed it to be well circumscribed with fibrous tissues, and the cystic space lined by keratinized epithelium. In addition, sweat glands and hair follicle‐like skin appendages were identified in the cystic wall, where a daughter cyst was also found. We suggested that this uncommon cyst had developed in the mandible, as a result of embryonic epithelium migration. The patient remained in good health during the three year follow‐up.
The retinoic acid receptor‐β (RAR‐β) mRNA expression in the oral squamous cell carcinoma associated with betel quid use
Authors: Kao Shou‐Yen , Tu Hsi‐Feng , Chang Kuo‐Wei , Chang Che‐Shoa , Yang Cheng‐Chei , Lin Shu‐Chun
Published: March 2003

Background:  Within the abundant retinoids nuclear receptors, abnormally low expression of the RAR‐β has been shown to contribute to neoplastic progression in oral epithelium in western countries. Distinctly different risk factors contributing to oral squamous cell carcinoma (OSCC) in epidemiologically different societies denote the value of exploring the role of RAR‐β expression in OSCC associated with betel quid (BQ) use in our society.

Methods:  We examined the cellular expression of RAR‐β using in situ hybridization (ISH) analysis on 38 pairs of surgical specimens of primary OSCC and non‐cancerous matched tissues (NCMT) to correlate with their clinico‐pathological features including age, sites of tumor, habit of BQ use, stage, size of primary tumor, lymph node metastasis, differentiation.

Results:  Of all cases analyzed, BQ users were significantly younger than non‐BQ users (51.2 ± 2.1 vs. 60.2 ± 2.6, P= 0.01). 52% OSCC of BQ users (13/25) and 23% OSCC of non‐BQ users (3/13) exhibited the absence of RAR‐β expression. In 17 paired‐samples from buccal mucosa (BM), most NCMT and less than half of OSCC exhibited RAR‐β expression (16/17, 94% vs. 8/17, 47%, P= 0.003). The RAR‐β expression was seen in the vast majority of the well‐differentiated OSCC and in less than half of the moderately differentiated OSCC only (15/20, 75% vs. 7/18, 39%, P= 0.03).

Conclusion:  A correlation between the loss of RAR‐β expression and more advanced histopathological grade tumors was observed. This study also suggests that the loss of RAR‐β expression is significant in BM OSCC, which preferentially occurs in BQ users.
Proliferation and differentation markers in snuff‐induced oral mucosal lesions
Authors: Merne Marina , Heinaro Ilkka , Lähteenoja Hannu , Syrjänen Stina
Published: March 2003

Background: Regular use of snuff is known to cause whitish oral mucosal lesions of variable severity at the usual quid placement site. The main aim of this study was to elucidate cellular mechanisms involved in snuff‐induced epithelial changes.

Methods: Expression patterns for markers of cell proliferation (PCNA, Ki‐67), cell cycle regulation (p53, p21), keratin changes (pankeratin, CK18, CK19), cell stress (HSP 70) and collagen type IV in 14 snuff‐induced oral mucosal lesions and 12 control samples were analyzed by immunohistochemistry (IHC).

Results: On light microscopy, all snuff‐induced lesions were characterized by a hyperkeratinized and thickened epithelium. Some vacuolized cells, markers of cell degeneration, were frequently seen (in 9/14 of the samples) in the superficial layers in epithelia. Expression of PCNA and Ki‐67 was found in a statistically significantly fewer cells in snuff‐induced lesions (P < 0.001) than in the controls. This indicates that epithelia in snuff‐induced lesions are not thickened as a result of increased cellular proliferation, but by protracted turnover of differentiating cells. Of cell cycle markers, p21 was found be up‐regulated in 4/14 snuff‐induced lesions, probably by p53‐independent pathways. Only two snuff‐induced lesions showed p53 positivity. However, the number of stained cells with p53 and p21 was not statistically different from that in controls. Expression of CK18, but not any alterations in CK19 expression, was seen in 5 of 14 snuff‐induced lesions. Snuff also seems to stimulate the expression of collagen type IV, possibly by basal cells, as indicated by the thickened staining of the basal lamina.

Conclusions: The findings of this study showing suppressed cellular proliferation and infrequent p53 dysfunction in snuff lesions may partly explain why dysplastic changes are seldom seen in mucosal lesions induced by the Scandinavian type of snuff.
The increase in the frequency of MICA gene A6 allele in oral squamous cell carcinoma
Authors: Chung‐Ji Liu , Yann‐Jinn Lee , Hsin‐Fu Liu , Ching‐Wen Dang , Che‐Shoa Chang , Yi‐Shing Leu , Kuo‐Wei Chang
Published: March 2003

Background: Oral squamous cell carcinoma (OSCC) was reported to be associated with immune function. The MICA (MHC class I chain‐related gene A) is expressed by keratinocytes and other epithelial cells, and its encoded protein interacts with γ/δ T cells localized in submucosa. The MICA also influences the heat shock protein function. We speculated that the alterations of MICA might influence the pathogenesis of OSCC through the aberration in presenting tumor antigens or heat shock protein. MICA gene has a triplet repeat (GCT) polymorphism in the transmembrane domain, resulting in five distinctive allelic patterns.

Methods: We analysed this MICA polymorphism in 67 OSCC patients and 351 randomly selected unrelated controls. By using the ABI Prism 377–18 DNA sequencer (Applied Biosystems, Foster City, CA, USA) to analyse the sample DNA PCR products. The number of micro‐satellite repeats was estimated with Genescan 672 software (Applied Biosystems) with a standard size marker of GS‐350 TAMRA (N,N,N,N‐tetramethyl‐6‐carbohydroxyl rhodamine; Applied Biosystems).

Results: The phenotype frequency of allele A6 of MICA in subjects with OSCC was significantly higher than that in controls (RR = 3.46, 95% CI = 1.73–6.94, P = 0.0002), as was the frequency of allele (RR = 2.64, 95% CI = 1.39–5.02, P = 0.002).

Conclusion: The results suggest that allele A6 in MICA might confer the risk of OSCC.
Gene Expression Analysis
Authors: Oetting William S.
Published: March 2003

The response of cells to extracellular signals usually requires altered expression of many genes, possibly including several distinct metabolic pathways. In some cases, only a subset of genes involved in such responses are known, which requires techniques to analyze changes in the expression of multiple genes, both known and unknown. Three techniques, two‐dimensional gel electrophoresis, differential display, and gene discovery arrays, provide opportunities for measuring changes in gene expression levels, as well as for identifying novel gene products.
Controlling Gene Expression in Mice with Tetracycline: Application in Pigment Cell Research
Authors: SHIN MYUNG K.
Published: March 2003

Genetic manipulation techniques are widely used in mice to study the functions of genes. The most common strategy for assessing in vivo function involves making irreversible changes in the genome by homologous recombination. To complement this approach, a number of systems have been developed that allow specific and controlled expression of a gene. One of the more versatile and promising systems is based on the tetracycline (tet) responsive bacterial tetracycline repressor (TetR). In recent years, the tet system has proven to be a valuable method for understanding the function of genes involved in a number of physiological processes, including mouse models for human diseases such as cancer and neurological and pigment disorders. This review will highlight the power and elegance of the tet system by focusing on its utility in the study of two pigment cell‐related biological problems, the pathogenesis of melanomas and melanocyte development in the embryo.
Cellular and Hormonal Regulation of Pigmentation in Human Ocular Melanocytes
Authors: Smith‐Thomas Linda C. , Moustafa Manar , Dawson Rebecca A. , Wagner Mark , Balafa Chariklia , Haycock John W. , H‐P Krauss Achim , Woodward David F. , Macneil Sheila
Published: March 2003

The purpose of this study was to examine some of the factors that may be relevant to regulating pigmentation in the human eye, specifically whether choroidal and iridial melanocytes are sensitive to regulation by epithelial and stromal cells and α‐melanocyte stimulating hormone (α‐MSH). Human choroidal and iridial melanocytes were established in culture and co‐cultured with epithelial cells and stromal cells derived both from skin and from eye in order to determine their influence on choroidal and iridial melanocyte dopa oxidase activity. In all cases, co‐culture of melanocytes with either epithelial cells or fibroblasts led to an increase in dopa oxidase activity during 5 days of co‐culture. The extent of the increase ranged from 60% (non‐significant) to as much as 185% when both fibroblasts and keratinocytes were present. The optimal ratio of fibroblasts to melanocytes was 1:10 (for dermal fibroblasts) or 1:2 (for iridial fibroblasts) and 1:1 for all epithelial cells to melanocytes. Both choroidal (three out of three cultures) and iridial (two out of three cultures) melanocytes showed increases in dopa oxidase activity to α‐MSH when cultured in Green's media but the same cells cultured in MCDB153 were unresponsive to α‐MSH. These in vitro studies suggest that ocular melanocytes have the capacity to be influenced by adjacent epithelial and stromal cells with respect to pigmentation.
Brightly Colored Pigmentation in Lower Vertebrates: Wonder Searching its Mechanisms and Significance in the Context of Phylogeny
Authors: Matsumoto Jiro
Published: March 2003

This is a biographical sketch of my research and its related personal episodes with respect to brightly colored pigmentation in lower vertebrates. It includes a brief story of the studies on; (a) pterinosomes as a specific site of pteridine deposition in xanthophores or erythrophores of fish and amphibians, (b) a mosaic phenotype of chromatophores occurring in the reptiles and its implication for their developmental origin and differentiation mechanisms, (c) erythrophoroma as a tumor of erythrophores in goldfish, (d) the pluripotentials of erythrophoroma cells for expression of neural crest‐derived characters in vitro, (e) pigment disorders occurring in hatchery‐raised flounders and (f) recognition of pigment cell types by murine tyrosinase genes transfected into an orange‐colored variant of medaka fish. Some of the personal affairs associated with the history of the Japanese community for pigment cell research were described to illustrate the background of these studies.
Redefining the Skin's Pigmentary System with a Novel Tyrosinase Assay
Authors: Han Rong , Baden Howard P. , Brissette Janice L. , Weiner Lorin
Published: March 2003

In mammalian skin, melanin is produced by melanocytes and transferred to epithelial cells, with the epithelial cells thought to receive pigment only and not generate it. Melanin formation requires the enzyme tyrosinase, which catalyzes multiple reactions in the melanin biosynthetic pathway. Here, we reassess cutaneous melanogenesis using tyramide‐based tyrosinase assay (TTA), a simple test for tyrosinase activity in situ. In the TTA procedure, tyrosinase reacts with biotinyl tyramide, causing the substrate to deposit near the enzyme. These biotinylated deposits are then visualized with streptavidin conjugated to a fluorescent dye. In the skin and eye, TTA was highly specific for tyrosinase and served as a sensitive indicator of pigment cell distribution and status. In clinical skin samples, the assay detected pigment cell defects, such as melanocytic nevi and vitiligo, providing confirmation of medical diagnoses. In murine skin, TTA identified a new tyrosinase‐positive cell type – the medullary cells of the hair – providing the first example of cutaneous epithelial cells with a melanogenic activity. Presumably, the epithelial tyrosinase originates in melanocytes and is acquired by medullary cells during pigment transfer. As tyrosinase by itself can generate pigment from tyrosine, it is likely that medullary cells produce melanin de novo. Thus, we propose that melanocytes convert medullary cells into pigment cells by transfer of the melanogenic apparatus, an unusual mechanism of differentiation that expands the skin's pigmentary system.