bluuebunny/crossref_metadata_2025 huggingface dataset:
Monitoring of transtubular potassium gradient in the diuretic management of patients with cirrhosis and ascites
Authors: Lim Young‐Suk , Han Jin Suk , Kim Kyung‐Ah , Yoon Jung‐Hwan , Kim Chung Yong , Lee Hyo‐Suk
Published: March 2003

Abstract: Background/Aims: Aldosterone antagonists are the diuretics of first choice in the treatment of cirrhotic ascites. However, there is still no reliable clinical parameter to evaluate their efficacy. Transtubular potassium gradient (TTKG), the accurate indicator of aldosterone bioactivity, may serve as a guide for the proper use of the aldosterone antagonists. Methods: In 23 patients with cirrhotic ascites, the daily administered initial dosage of 100 mg of spironolactone was increased by 100 mg/day at intervals of 5 days until either diuresis commenced or TTKG fell below 3.0, the value indicating complete blockade of aldosterone bioactivity. For the non‐responders with TTKG lower than 3.0, furosemide was given in addition to spironolactone.Results: Basal TTKG correlated significantly with plasma aldosterone concentration (r = 0.60, P = 0.002). Spironolactone induced the decrease of TTKG in 20 patients, from 5.3 ± 0.5 to 2.9 ± 0.2 (mean ± SE, P < 0.001). A TTKG value of 3.0 could classify seven patients, who did not respond to low dose spironolactone, into two distinct groups at that time, indicating different further diuretic regimen. All patients achieved diuretic responses without complication by this TTKG‐guided modification of diuretics. Conclusions: TTKG may be a suitable guide for the diuretic management of cirrhotic ascites by accurately reflecting the effect of aldosterone antagonists.
Cytotoxic response of sinusoidal endothelial cells to polymorphonuclear leukocytes and its potential implication in hypoxia‐reoxygenation injury
Authors: Lasnier E. , Blanc M. C. , Housset C. , Rey C. , Roch‐Arveiller M. , Vaubourdolle M.
Published: March 2003

Abstract: Aims: Interactions between polymorphonuclear leukocytes (PMN) and sinusoidal endothelial cells (SEC) may contribute to ischemia‐reperfusion injury. The aim of the study was to determine the influence of PMN hypoxia‐reoxygenation and degranulation, on SEC toxic response. Methods: PMNs collected from rat pleural cavity underwent hypoxia‐ reoxygenation or N‐formyl‐methionyl‐leucyl‐phenylalanine (fMLP) degranulation treatment, and were then separated from their conditioned medium. Rat SECs were incubated either with PMNs in coculture or with their conditioned medium, for 210 min. Oxidative metabolism in PMNs was measured by chemiluminescence. LDH release and elastase activity were measured in SEC supernatants. Results: PMN‐conditioned medium induced an increase in LDH release in SECs. Hypoxia‐reoxygenation of PMNs induced an increase in their chemiluminescent response without increasing the cytotoxic effect of their conditioned medium. By contrast, the cytotoxic effect of conditioned medium was increased following PMN treatment with fMLP. In the latter case, cytotoxicity was combined with a rise in the elastase activity released in the supernatants, but was not reduced by inhibitors of elastase or of other proteases. Conclusions: The results indicate that toxic products are released, at least in part through degranulation, by PMNs, and induce cytotoxicity in SECs. This mechanism may contribute to SEC injury during hypoxia‐reoxygenation.
Use of human CD3 monoclonal antibody for accurate CD4+ and CD8+ lymphocyte determinations in macaques: Phenotypic characterization of the CD3−CD8+ cell subset
Authors: Ibegbu Chris , Brodie‐Hill Anne , Kourtis Athena P. , Carter Ashley , McClure Harold , Wei Chen Zheng , Nahmias André J.
Published: March 2003

Macaque monkeys are frequently used in models for studies of infectious diseases, immunity, transplantation and vaccine development. Such use is largely due to the conservation of functionally important cell surface molecules and the phylogenetic proximity of their immune systems to that of humans. Some monoclonal antibodies (mAb) raised against human leukocyte antigens can be utilized in the monkey. Until recently, many primate centers have utilized the CD2 monoclonal antibody to enumerate T lymphocytes. We have evaluated the anti‐human CD3 mAb in macaques and sooty mangabeys. Using this monoclonal antibody, pigtailed macaques were found to have a much higher proportion of CD2+CD3−CD8+ cells as compared with rhesus macaques and sooty mangabeys. Such cells comprised approximately one‐half of all CD8+ cells in the pigtailed macaque, but only one‐quarter of CD8+ cells in the rhesus, and one‐fifth in the sooty mangabey. Use of the CD2 monoclonal antibody as the T‐cell marker resulted in underestimating CD4/CD8 ratios compared with using the CD3 mAb in pigtailed macaques. Phenotypic characterization of this subset of CD3−CD8+ cells indicated that they are CD16+, CD45RA+, CD11b+, CD69+ and CD28−. This would indicate that these cells represent an activated natural killer cell subset.
Congenitally caused fused labia in the common marmoset (Callithrix jacchus)
Authors: Isachenko E.F. , Nayudu P.L. , Isachenko V.V. , Nawroth F. , Michelmann H.W.
Published: March 2003

Abstract: In this paper, the occurrence of an external genital abnormality in female marmoset monkeys (fused labia) is discussed. This malformation was detected, for the first time, in a group of animals at the German Primate Center (GPC), Goettingen. The malformed vulva was completely sealed except for an opening of 1.5–2.5 mm around the urethra sufficient for urination. Because of this defect the animals were not able to copulate. As a consequence, the affected females were functionally infertile although they had a normal genital tract and a regular cycle. This vulvar abnormality was found in 12 females, offspring of 10 pairs in which either one or both came to the German Primate Center from two genetically related colonies in Munich, Germany, and one colony in Basel, Switzerland. The abnormality appeared to be recessive and inheritable from either parent. In pairs in which both animals were from one of the mentioned colonies, 45% of the female offspring were affected. In pairs where only one partner came from these colonies, 26% of female offspring had the malformation. These results indicate that avoidance of inbreeding, which is frequently performed in primate colonies, may reduce, but not eliminate the expression of abnormalities of genetic origin. Therefore selective breeding is required, and, in colonies where these recessive mutations are widespread, the development of genetic screening tests would be advantageous.
A study on the preparation of zinc ferrite
Authors: Chen Hsi‐Kuei , Yang Ching‐Yi
Published: March 2003

The reaction of Fe2O3/ZnO powder mixture to prepare zinc ferrite in a nitrogen flow stream was investigated by an X‐ray diffraction method. Experimental results indicated that the reaction rate could be increased by an increase in density of solid sample or reaction temperature. The rate was also found to be increased by reducing the grain size of zinc oxide or iron oxide and the molar ratio of Fe2O3/ZnO.
Volumetric effects of ZnTe, CdTe and HgTe compounds at melting and subsequent heating
Authors: Glazov V. M. , Pavlova L. M.
Published: March 2003

The temperature dependence of the density of CdTe, ZnTe and HgTe compounds was studied by means of the γ– ray attenuation method both in solid and liquid states. A decrease in the density in the course of the crystal → melt phase transition and subsequent heating for ZnTe and CdTe is obtained. The volume effect during the HgTe melting is negative. According to our evaluations, the increase of the external pressure should result in an increase of the fusion temperature for ZnTe and CdTe. The dT/dP coefficient of the HgTe at the melting point is negative. The density of the molten HgTe compound changes along a curve with a maximum. This anomaly is explained by the thermal dissociation of the HgTe with the formation of 2 complex associates in the liquid phase. The thermal expansion of the Zn and Cd tellurides is considered on the basis of the characteristics of the interatomic bonds strength.
CO2 emissions of the Swedish steel industry
Authors: Sandberg Hans , Lagneborg Rune , Lindblad Birgitta , Axelsson Helén , Bentell Lars
Published: March 2003

The energy consumption and CO2 emission of Swedish production of flat and long products of structural steel have been assessed by means of LCI data from the IISI study. Two general factors reduce the expenditure of energy and CO2 emission in Swedish production of both flat and long products: energy efficient steel processes; and extremely low CO2 emissions for generation of electricity. For flat steel products two specific features also contribute to their low energy consumption and CO2 emission: the use of magnetite iron ore instead of hematite; and a product programme with a uniquely large share of high strength steels. The latter allows significant weight savings in end products, thus resulting in global net reductions of energy consumption and CO2 emission. Even when transport of Swedish products to export markets are included, the Swedish figures are more favourable than those of steels manufactured domestically in their respective markets.
Chemical diffusion coefficients in solid Al‐Li alloys at low Li concentrations
Authors: Ga̧sior W. , Moser Z.
Published: March 2003

The galvanostatic method was used in measurements of the chemical diffusion coefficient in the Al‐rich aluminium‐lithium alloys. The experiments were performed using electrochemical concentration cells with the liquid electrolytes LiCl‐LiF, LiCl‐KCl and LiCl‐KCl‐CsCl at 4 temperatures 568 K, 638 K, 780 K and 863 K. The observed values of the chemical diffusion coefficients in the α(Al) solid alloys of the Al‐Li system are of the order from 10−11 cm2/s at 568 K to 10−8 cm2/s at 863 K. Taking from the literature the self‐diffusion coefficient of aluminium, the self‐diffusion coefficients of Li were calculated from the Darken relation. Finally, the Arrhenius equation describing the dependence of the self‐diffusion coefficient on temperature was worked out and compared with the earlier published results from different experimental techniques. The empirical relation describing the dependence of the activation energy on the melting temperature of metals was confirmed.
Distribution of Al and Ca between ferro‐silicons and CaO‐Al2O3‐SiO2 slags at 1450°C
Authors: Dumay Christophe , Allibert Michel
Published: March 2003

Several ferro‐silicon liquid alloys (65 wt% Si called FeSi65) were equilibrated in SiC‐coated graphite crucibles with CaO‐Al2O3‐SiO2 liquid slags at 1350, 1450 and 1550°C. Durations of 12 and 48 h were required to reach a thermodynamic equilibrium, depending on the viscosity of the slag. Chemical analysis of the phases after quenching in air allowed a correspondence to be found between the slag composition and the residual amounts of Al and Ca in the alloys. Results were interpreted in terms of infinitely diluted solution of these trace elements in the ferro‐silicon. The isoconcentration lines of Al and Ca in a ferro‐silicon alloy at 65% Si are presented for the CaO‐Al2O3‐SiO2 liquid slags at 1450°C. Activity coefficient values are proposed for Al and Ca at infinite dilution in FeSi65. Diffusion experiments were also carried out to get information on the exchange kinetics.
Modeling micro‐inclusion growth and separation ingas‐stirred ladles
Authors: Sheng Dong‐Yuan , Söder Mats , Jönsson Pär , Jonsson Lage
Published: March 2003

Mathematical models of inclusion behavior in stirred ladles are useful both for increasing our fundamental understanding of the growth and removal of inclusions as well as for future use in process control. This study reports on some efforts to use both static and dynamic modeling to better understand inclusion behavior in gas‐stirred ladles. A computational‐fluid‐dynamics mathematical model of a gas‐stirred ladle was developed earlier. In the investigation covered in this report, instantaneous fluid‐flow results from the model were used in combination with inclusion growth and removal theories in order to study the importance of bubbles on inclusion flotation. The study results proved to be highly dependent on the theory used to describe bubble flotation. The model of the gas‐stirred ladle was also used together with the inclusion theories to study the transient behavior of inclusions during growth and removal. The dynamic simulation results indicated that inclusion concentration gradients exist. The most important research task in the near future is to verify static and dynamic modeling results of inclusion behavior during stirring with experimental data. Here, the authors feel that carefully performed plant trials could provide useful information.
Dominance of autochthonous autotrophic carbon in food webs of heterotrophic rivers
Authors: Thorp James H. , Delong Michael D.
Published: March 2003

This paper addresses the river heterotrophy paradox, “How can animal biomass within riverine food webs be fueled primarily by autochthonous autotrophic production if the ecosystem as a whole is heterotrophic?”. Reviewed, stable isotope data from tropical, temperate, and arctic rivers provide evidence consistent with the revised riverine productivity model (RPM): “The primary, annual energy source supporting overall metazoan production and species diversity in mid‐ to higher‐trophic levels of most rivers (≥4th order) is autochthonous primary production entering food webs via algal‐grazer and decomposer pathways”. The revised RPM does not conflict with the heterotrophy paradox because: (a) the decomposer (microbial loop) food pathway processes most of the transported, allochthonous and autochthonous carbon and, with algal respiration in some cases, is primarily responsible for a river's heterotrophic state (P/R<1); but (b) biomass production of mid‐ to higher‐trophic levels is principally supported by an algal‐grazer (phytoplankton and benthic microalgae) pathway that is only weakly linked to the decomposer pathway. The reason the algal‐grazer pathway supports the majority of metazoan biomass is that allochthonous carbon is mostly recalcitrant, whereas carbon from autochthonous primary production, though much less plentiful, is commonly more labile (easier to assimilate), contains more energy per unit mass, and is typically preferred by metazoa.
Metapopulation dynamics of the bog fritillary butterfly: demographic processes in a patchy population
Authors: Schtickzelle Nicolas , Le Boulengé Eric , Baguette Michel
Published: March 2003

Metapopulation models predicting the persistence of species on the verge of extinction in fragmented landscapes have to include local population dynamics. In this paper, we report on a 9‐yr study in which a patchy population of the bog fritillary was monitored each year, with special focus on quantifying demographic parameters. We parameterised various constrained linear models (CLM) with capture‐mark‐recapture (CMR) data collected in the field each year and we tested the effects of several variables on demographic parameters. Selecting the best CLM, we estimated the mean and the variance of (1) individual parameters (survival and catchability) and (2) population features (population size, sex‐ratio and recruitment). Survival was not related to the age of the individual but decreased continuously during the flight period, which means that lifetime expectancy is conversely related to the delay between the moment of the emergence of a given individual as compared to the emergence of the first adult in the population. Survival was lower in males than in females, as a consequence of male mate‐locating behaviour. Daily population size fits a parabolic distribution in both sexes, males appearing, reaching their abundance peak and dying before females. Yearly variation in the sex‐ratio is the consequence of the between‐sex difference in the recruitment curve. Total adult population size shows large variations between years. Analysis of the relation between growth rate and abundance indicates density dependence, probably related to parasitism of the larval stages. Density at the equilibrium is about 200 adults/ha.
Effects of population size, seed predation and plant size on male and female reproductive success inVincetoxicum hirundinaria(Asclepiadaceae)
Authors: Leimu Roosa , Syrjänen Kimmo
Published: March 2003

Here we present the results of a study on the effects of population size, seed predation, and plant size on male and female reproductive success in tenVincetoxicum hirundinariapopulations in southwestern Finland. We investigated male reproductive success by recording pollinia removal, and studying pollen quality and quantity. Pod and seed production, and the number of ovules per ovary were counted to estimate female reproductive success. Both pollen quality and pollinia removal were higher in smallV. hirundinariapopulations compared to large populations. In contrast, the quantity of pollen was higher in large populations than in small populations. Pod initiation was higher in large populations. However, large populations had higher abortion rates and proportionally fewer intact pods. Plant size did not affect male reproductive success whereas pod and seed production correlated positively with plant size, although only in large populations. Population size had no clear impact on seed predation intensities. Variation was, however, observed among populations. Larger plant individuals suffered from an increased risk of being attacked only in two populations. This correlation was not clearly attributed to plant population size. The results of this study suggest that reproductive success inV. hirundinariamay be highly variable and this variation is to some extent explained by population size. Further, population size affected male and female reproductive success differently.
Mechanisms of resistance of Mediterranean annual communities to invasion by Conyza bonariensis: effects of native functional composition
Authors: Prieur‐Richard Anne‐Hélène , Lavorel Sandra , Dos Santos Anabelle , Grigulis Karl
Published: March 2003

Recent studies have shown that a high species or functional group richness may not always lead to a greater resistance of plant communities to invasion, whereas species and/or functional group composition can more reliably predict invasion resistance. The aim of this study was to understand the mechanisms through which functional group composition can influence the resistance of Mediterranean annual communities to invasion by the exotic Conyza bonariensis. To analyse the effects of functional composition on the performance of individuals introduced as seedlings we first examined the relationships between the demographic and vegetative parameters of C. bonariensis and the biomass achieved by each functional group (grasses, legumes and Asteraceae rosettes) in synthetic communities. As a further step to approach the mechanisms involved in community resistance to invasion, we included in the analyses measurements of functional variables taken within the synthetic communities.

In agreement with earlier results and theory suggesting that high nutrient availability can favour invasions, an abundant legume biomass in communities increased the final biomass and net fecundity of C. bonariensis, due to positive effects on soil nitrate concentration. Survival and establishment of C. bonariensis were mainly favoured by a high biomass of Asteraceae. Additional results from measurements of herbivory suggested that C. bonariensis survival wasn't related to abiotic conditions but may be owed to a protection against herbivores in plots with abundant Asteraceae. Establishment was on the other hand likely to be hindered by the effects of abundant grass and legume foliage on light quality, and therefore easier within an Asteraceae canopy.

We conclude that invasion of Mediterranean old fields by species with biologies similar to C. bonariensis could be limited by favouring communities dominated by annual grasses.
Argyrophilic nucleolar organizer regions (AgNORs) in mucosal epithelium under experimental denture bases in rats
Authors: Hara Tetsuya , Sato Takashi , Mori Shingo , Shirai Hajime , Maruo Yukinori , Minagi Shogo
Published: March 2003

Abstract: The purpose of this study was to evaluate changes in the argyrophilic nucleolar organizer region (AgNOR) counts in mucosal epithelium induced by continuous or intermittent compressive pressure exerted through experimental denture bases and to examine the relationships between the AgNOR count, histopathological changes and the intensity of the pressure under denture bases. Continuous or intermittent compressive pressure exerted through the denture bases was applied to the hard palate of the molar region in rats. A morphometric analysis of AgNORs was performed in denture‐supporting tissue 3 days and 1, 2, 4, 8, 12 and 20 weeks after the denture insertion. From the results of this study, it was found that non‐pressure contact of the denture bases with palatal tissues did not change the AgNOR count. The AgNOR count was decreased by continuous or intermittent compressive pressure, and then recovered to almost the same level as with the non‐pressure contact at 20 weeks following a decrease of the pressure. The AgNOR counts in the epithelium under the denture bases were revealed to be related to the histopathological changes in the denture‐supporting tissues and the intensity of the pressure under the denture bases.
p53, bcl‐2 and bax abnormalities in non‐Hodgkin’s lymphomas of the head and neck
Authors: Miyauchi Miwa , Higashikawa Koichiro , Sugiyama Masaru , Harada Tadashi , Sasaki Naomi , Ishikawa Takenori
Published: March 2003

Abstract: In the present study, mutations or protein expression of p53, bcl‐2 and bax are reported in 13 non‐Hodgkin’s B‐cell lymphomas of the head and neck. Nine of 13 cases (69.2%) expressed p53 protein and 7 (53.8%) showed gene mutations. On comparing the results of immunostaining and SSCP analysis, there were two cases showing discrepancies between the p53 protein expression and gene mutations. Bcl‐2 protein expression was observed in only two cases of follicular lymphoma. On the other hand, bax protein was detected in all 13 cases. One case with mutated bax gene showed a lower expression with a reduced frequency of bax‐positive cells than the other 12. These results suggest that inactivation of p53 may be closely related to development and/or progression of these NHLs, and that bcl‐2 and bax protein may not have a role.
Enamel proteins and extracellular matrix molecules are co ‐localized in the pseudocystic stromal space of adenomatoid odontogenic tumor
Authors: Murata Masashi , Cheng Jun , Horino Kazuhito , Hara Kohji , Shimokawa Hitoyata , Saku Takashi
Published: March 2003

Abstract: In order to examine the functional differentiation of tumor cells of adenomatoid odontogenic tumor (AOT) as ameloblasts and to determine the participation of the extracellular matrix (ECM) in the formation of its characteristic histologic architecture, tissue samples from five cases of adenomatoid odontogenic tumor were examined by immunohistochemical staining for enamel proteins and ECM molecules. Amelogenin, enamelin, laminin, heparan sulfate proteoglycan, fibronectin, collagen type IV and type V were immunolocalized within the luminal space and along the inner rim of duct‐like structures. Eosinophilic hyaline droplets within the whorled or rosette masses of tumor cells showed basically the same staining pattern as the luminal contents. High columnar tumor cells that formed duct‐like structures were immunopositive for amelogenin, while the staining intensity decreased with flattening of the cells, which was a result of luminal growth. The findings suggest that the constituent cells of duct‐like structures are differentiated once to ameloblasts but fail to mature further due instead to increased production of ECM molecules and due to their retention in the lumina. It is possible to regard these special structures in AOT as stromal pseudocysts.
The oral manifestations of chronic graft‐versus‐host disease (cGVHD) in paediatric allogeneic bone marrow transplant recipients
Authors: Nicolatou‐Galitis Ourania , Kitra Vassiliki , Van Vliet‐Constantinidou Catherine , Peristeri Julia , Goussetis Eugene , Petropoulos Dimitrios , Grafakos Stelios
Published: March 2003

Abstract: The oral manifestations of chronic graft‐versus‐host disease (cGVHD) in eight allogeneic bone marrow transplant (BMT) paediatric recipients were studied clinically, and lip biopsies were performed in seven of them. A prominent lichenoid reaction was observed in four patients, two with accompanying ulceration. Superficial mucoceles were present in three children. Clinically obvious xerostomia was seen in seven patients. Lip biopsies were positive and correlated with the clinical manifestations. Both clinical and histological findings confirmed the diagnosis of cGVHD. In three additional children, with systemic manifestations indicating cGVHD, the oral mucosa was clinically and histologically normal, and the systemic manifestations were, thus, attributed to drug reactions. The above findings indicate the high value of oral examination in diagnosing or confirming paediatric cGVHD. Superficial mucoceles, reported for the first time in paediatric recipients, seem to be important in the early diagnosis of cGVHD.
Some specific human leukocyte antigen (HLA)‐DR/DQ haplotypes are more important than individual HLA‐DR and ‐DQ phenotypes for the development of mucocutaneous type of Behçet’s disease and for disease shift from recurrent aphthous stomatitis to mucocutaneous type of Behçet’s disease
Authors: Sun Andy , Hsieh Rhong‐Phong , Chu Chien‐Ts , Wang Jeng‐Tzung , Liu Bu‐Yuan , Chiang Chun‐Pin
Published: March 2003

Abstract: The phenotype and haplotype frequencies of human leukocyte antigens (HLA)‐DR and ‐DQ in 32 Chinese patients with the mucocutaneous (MC) type of Behçet’s disease (BD) were calculated and compared with those in 310 healthy control Chinese and with those in 80 Chinese patients with recurrent aphthous stomatitis (RAS). We found that the phenotype frequency of HLA‐DRw8 [corrected P (Pc)<0.005] and the haplotype frequencies of HLA‐DRw8/DQw1 (Pc<0.005), ‐DRw8/DQw5(w1) (Pc<0.0005), ‐DRw12(5)/DQw1 (Pc<0.005), ‐DRw12(5)/DQw6(w1) (Pc< 0.0005), and ‐DRw52/DQw1 (Pc<0.005) in patients with the MC type of BD were significantly greater than those in healthy control subjects. This finding suggests that individual Chinese with HLA‐DRw8 antigen and HLA‐DRw8/DQw1, ‐DRw8/DQw5(w1), ‐DRw12(5)/DQw1, ‐DRw12(5)/DQw6(w1) and ‐DRw52/DQw1 haplotypes are more likely to have the MC type of BD. Furthermore, the relative risks (RRs) of HLA–DRw8/DQw1 (5.6), ‐DRw8/DQw5 (w1) (10.0), and ‐DRw12(5)/DQw6(w1) (14.4) haplotypes in patients with the MC type of BD were equal to or higher than the RR of HLA‐DRw8 phenotype (5.6), suggesting that some of the HLA‐DR/DQ haplotypes may play more important roles than the individual HLA‐DR and ‐DQ phenotypes for the development of the MC type of BD. The phenotype frequencies of HLA‐DR5 (Pc<0.01), ‐DRw8 (Pc<0.005) and ‐DQw1 (Pc<0.05) as well as the haplotype frequencies of HLA‐DR5/DQw1 (Pc<0.005) and ‐DRw8/DQw1 (Pc<0.00005) in patients with the MC type of BD were significantly higher than those in patients with RAS. Moreover, the RRs of HLA‐DR5/DQw1 (29.1) and ‐DRw8/DQw1 (47.4) haplotypes were greater than the RRs of HLA‐DR5 (10.4), ‐DRw8 (23.4) and ‐DQw1 (4.0) antigens. These results suggest that some specific HLA‐DR/DQ haplotypes may be more important than the individual HLA‐DR and ‐DQ phenotypes in the disease shift from RAS to the MC type of BD.
Areca nut extract lowers the permeability of vaginal mucosa to reduced arecoline and arecaidine
Authors: Van Der Bijl P. , Van Eyk A. D.
Published: March 2003

Abstract: Areca nut chewing has been implicated in the development of oral cancer and oral submucous fibrosis. Arecoline and arecaidine, which are alkaloids present in the areca nut, are thought to play a major role in the development of adverse effects resulting from this chewing habit. Because these alkaloids appear to be associated with the development of the above diseases, we determined their diffusion kinetics through human vaginal mucosa in the presence and absence of a 1% areca nut extract. Seven clinically healthy vaginal mucosa specimens (mean patient age±standard deviation, 52±13 years; age range, 38–74 years) were obtained during surgery. In vitro flux values of reduced arecoline and arecaidine (r‐arecoline and r‐arecaidine) were determined through use of a flow‐through diffusion apparatus. Analysis of variance, a Duncan multiple range test, and an unpaired t‐test were used to determine steady state kinetics and flux differences over time intervals. The flux values across vaginal mucosa of r‐arecoline and r‐arecaidine were decreased in the presence of 1% areca nut extract. For r‐arecoline, these flux values were significantly lower statistically when compared to those obtained in the absence of areca nut extract. These findings concur with results previously obtained for water, where the astringent action of the tannins present in the areca nut extract was thought to alter the barrier properties of the epithelium, resulting in decreased permeability.
Prediction of delayed neck metastasis in patients with stage I/II squamous cell carcinoma of the tongue
Authors: Okamoto Masumi , Nishimine Masayoshi , Kishi Munehiro , Kirita Tadaaki , Sugimura Masahito , Nakamura Mitsutoshi , Konishi Noboru
Published: March 2003

Background:  The incidence of delayed neck metastasis (DNM) in patients with squamous cell carcinoma (SCC) of the tongue is reported to be 20% to 50%. Although clinically negative cervical lymph nodes (N0) are associated with a good outcome, the prognosis is poor in patients with DNM. The aim of this study was to evaluate the clinicopathological and immunohistochemical parameters associated with DNM in patients with stage I/II SCC.

Methods:  Fifty nine patients, with previously untreated stage I/II carcinoma, underwent examination of clinicopathological and immunohistochemical parameters and incidence of DNM. A linear discriminant analysis was used to analyze prognostic factors and to determine the probability of DNM occurring.

Results:  DNM occurred in 14 (24%) subjects of the 59 study patients, level I to level III, within 5 years. Parameters such as gender and age, disease stage, tumor size and histological grade, tumor location, degree of tumor invasion and expression of VEGF, E‐cadherin or Ki‐67 showed no significant correlation with the occurrence of DNM; however, factors such as tumor morphology, tumor thickness greater than 4 mm, and Flt‐4 expression were significantly associated with development of DNM.

Conclusions:  Such factors provide useful information with regard to DNM and the prognosis. We concluded that patients with early SCC whose tumors are > 4 mm in thickness and immunopositive for Flt‐4 are particularly at risk of developing DNM.
Expression of hMSH2 and hMLH1 proteins of the human DNA mismatch repair system in salivary gland tumors
Authors: Castrilli Graziella , Fabiano Alfredo , La Torre Giampiero , Marigo Luca , Piantelli Chiara , Perfetti Giorgio , Ranelletti Franco O. , Piantelli Mauro
Published: March 2003

Background:  The human DNA mismatch repair (hMMR) system plays an important role in reducing mutation and maintaining genomic stability. The MMR system in human cells is composed of at least six genes (hMSH2, hMLH1, hMSH3, hPMS1, hPMS2 and GTBP/hMSH6). In particular, hMSH2 and hMLH1 are expressed in cells undergoing rapid renewal; their reduced expression has been reported in several tumors.

Methods:  We examined the expression of hMSH2 and hMLH1 by immunohistochemistry in tumor specimens from 43 patients with primary tumors.

Results:  All carcinomas (n = 20) expressed these proteins. In addition, when compared to pleomorphic adenomas, malignant tumors contained significantly (P < 0.01) higher proportions of hMSH2 (56.1 ± 31.5 vs. 31.1 ± 22.6) and hMLH1 (27.9 ± 26.0 vs. 14.0 ± 12.6) positive cells. Warthin's tumors showed no specific nuclear staining of tumor cells for both hMSH2 and hMLH1.

Conclusions:  These data suggest a minor, if any, role for a defect in the hMMR system in the pathogenesis of malignant salivary gland tumors.
A Possible Mechanism for Feedback Regulation of the Mouse Tyrosinase Gene by its 3′ Non‐Coding RNA Fragments
Authors: TAKEUCHI SAKAE , TAKEUCHI TAKUJI , YAMAMOTO HIROAKI
Published: March 2003

The 5′ upstream regulatory region of the mouse tyrosinase gene contains a long (GA)n sequence, that may be capable of adopting a triple‐helical conformation (triplex). We analyzed protein‐DNA interactions in a part of the 5′ upstream region containing the (GA)n sequence by gel retardation analysis and found evidence for a cell type‐specific protein(s) that bound to this region. We also found a (TC)10 sequence about 100 bp downstream from a polyadenylation site of the gene. Examination of tyrosinase cDNAs and Northern analysis indicated that this sequence is transcribed and removed during 3′ end‐processing of the mRNA. Based on the hypothesis that the (TC)10 sequence binds to the (GA)n sequence and forms an intermolecular triplex, we performed the same gel retardation assay in the presence of the 3′ non‐coding RNA fragments containing the (UC)10 sequence. The probe DNA failed to interact with the cell type‐specific protein(s). These results suggest a novel hypothesis for the regulation of the mouse tyrosinase gene, i.e. that the 3′ non‐coding RNA fragments of mouse tyrosinase transcripts suppress its own expression at the transcriptional level. This might occur by preventing cell type‐specific protein factor(s) from binding to the regulatory cis‐elements in the 5′ upstream region of the gene, possibly through a triplex formation, although this hypothesis remains to be proven.
Involvement of Nitric Oxide in UVB‐Induced Pigmentation in Guinea Pig Skin
Authors: HORIKOSHI TOSHIO , NAKAHARA MICHIO , KAMINAGA HIROKO , SASAKI MINORU , UCHIWA HIDEYO , MIYACHI YOSHIKI
Published: March 2003

Ultraviolet (UV) B irradiation evokes erythema and delayed pigmentation in skin, where a variety of toxic and modulating events are known to be involved. Nitric oxide (NO) is generated from l ‐arginine by NO synthases (NOS). Production of NO is enhanced in response to UVB‐stimulation and has an important role in the development of erythema. NO has recently been demonstrated as a melanogen which stimulates melanocytes in vitro, however, no known in vivo data has been reported to support this finding. In this study, we investigated the contribution of NO with UV‐induced pigmentation in an animal model using an NOS inhibitor. UVB‐induced erythema in guinea pig skin was reduced when an NOS inhibitor,
l‐NAME (N‐nitro‐
l‐arginine methylester hydrochloride), was topically applied to the skin daily, beginning 3 days before UVB‐irradiation. Delayed pigmentation and an increased number of DOPA‐positive melanocytes in the skin were markedly suppressed by sequential daily treatment with
l‐NAME. Furthermore, melanin content 13 days after UVB‐irradiation was significantly lower in skin treated with
l‐NAME than in the controls. In contrast,
d‐NAME (N‐nitro‐
d‐arginine methylester hydrochloride), an ineffective isomer of
l‐NAME, demonstrated no effect on these UV‐induced skin responses. These results suggest that NO production may contribute to the regulation of UVB‐induced pigmentation.
Keratinocyte–Melanocyte Interactions During Melanosome Transfer
Authors: Seiberg Miri
Published: March 2003

The epidermal–melanin unit is composed of one melanocyte and approximately 36 neighboring keratinocytes, working in synchrony to produce and distribute melanin. Melanin is synthesized in melanosomes, transferred to the dendrite tips, and translocated into keratinocytes, forming caps over the keratinocyte nuclei. The molecular and cellular mechanisms involved in melanosome transfer and the keratinocyte–melanocyte interactions required for this process are not yet completely understood. Suggested mechanisms of melanosome transfer include melanosome release and endocytosis, direct inoculation (‘injection’), keratinocyte–melanocyte membrane fusion, and phagocytosis. Studies of the keratinocyte receptor protease‐activated receptor‐2 (PAR‐2) support the phagocytosis theory. PAR‐2 controls melanosome ingestion and phagocytosis by keratinocytes and exerts a regulatory role in skin pigmentation. Modulation of PAR‐2 activity can enhance or decrease melanosome transfer and affects pigmentation only when there is keratinocyte–melanocyte contact. Moreover, PAR‐2 is induced by UV irradiation and inhibition of PAR‐2 activation results in the prevention of UVB‐induced tanning. The role of PAR‐2 in mediating UV‐induced responses remains to be elucidated.
Variation in Melanin Content and Composition in Type V and VI Photoexposed and Photoprotected Human Skin: The Dominant Role of DHI
Authors: ALALUF SIMON , HEATH ALAN , CARTER NIK , ATKINS DEREK , MAHALINGAM HARISH , BARRETT KAREN , KOLB RIA , SMIT NICO
Published: March 2003

A combination of techniques, including high‐performance liquid chromatography (HPLC), spectrophotometric measurements, and a novel method for quantifying melanosome morphology, were applied to the analysis of melanin content and composition in highly pigmented (Fitzpatrick type V and VI) human skin. We found that total epidermal melanin content is significantly elevated in photoexposed type V and VI skin (∼1.6×), while analysis of individual melanin components suggests that pheomelanin content increases only slightly, whereas 5,6‐dihydroxyindole‐2‐carboxylic acid (DHICA)‐eumelanin and to a greater extent 5,6‐dihydroxyindole (DHI)‐eumelanin content are both markedly elevated. Analysis of the relative composition of epidermal melanin in these subjects revealed that DHI‐eumelanin is the largest single component (∼60–70%), followed by DHICA‐eumelanin (25–35%), with pheomelanin being a relatively minor component (2–8%). Moreover, there was a comparative enrichment of DHI‐eumelanin at photoexposed sites, with a corresponding decline in the relative contributions from DHICA‐eumelanin and pheomelanin. There was also a good correlation and close agreement between the concentration of spheroidal melanosomes determined by morphological image analysis and the concentration of pheomelanin determined by a combination of HPLC and spectrophotometric analysis (r=0.89, P<0.02). This study demonstrates the usefulness of melanosome morphology analysis as a sensitive new method for the quantification of melanin composition in human skin. The data also suggest that DHI‐eumelanin formation is the dominant pathway for melanin synthesis in heavily pigmented (Fitzpatrick V and VI) skin types in vivo, and is the favoured pathway when melanin production is increased in chronically photoexposed skin.
Norepinephrine Induces Apoptosis in Skin Melanophores by Attenuating cAMP‐PKA Signals Via α2‐Adrenoceptors in the Medaka, Oryzias Latipes
Authors: UCHIDA‐OKA NAO , SUGIMOTO MASAZUMI
Published: March 2003

The density of skin melanophores in many teleost fish decreases during long‐term adaptation to a white background. Using the medaka, Oryzias latipes, we previously reported that apoptosis is responsible for the decrease in melanophores, and that a sympathetic neurotransmitter, norepinephrine (NE), induces their apoptosis in skin tissue cultures. In this study, we show that NE‐induced apoptosis of melanophores is mediated by the activation of α2‐adrenoceptors. Clonidine, an α2‐adrenoceptor agonist, induced apoptotic melanophore death in skin organ culture, while phenylephrine, an α1‐adrenoceptor agonist, had no effect. NE‐induced apoptosis was diminished by an α2‐adrenoceptor antagonist, yohimbine, but an α1‐adrenoceptor antagonist, prazosin, did not abrogate the effect of NE. Furthermore, forskolin inhibited NE‐induced apoptosis, while an inhibitor of PKA, H‐89, mimicked the effect of NE. These results suggest that NE induces apoptosis in melanophores by attenuating cAMP‐PKA signaling via α2‐adrenoceptors.
Changes in the Proliferative Activity of Epidermal Melanocytes in Serum‐Free Primary Culture During the Development of Ultraviolet Radiation B‐Induced Pigmented Spots in Hairless Mice
Authors: Furuya Rikako , Akiu Satoru , Ideta Ritsuro , Naganuma Masako , Fukuda Minoru , Hirobe Tomohisa
Published: March 2003

Long‐term exposure to ultraviolet radiation B (UVB) induced pigmented spots in the dorsal skin of hairless mice of strain (HR‐1 X HR/De)F1. To clarify the cellular mechanism for the development of these UVB‐induced pigmented spots, we investigated changes in the proliferative activity of epidermal melanoblasts and melanocytes in the dorsal skin at various weeks after UVB irradiation. Epidermal cell suspensions from the dorsal skin of hairless mice were cultured in a serum‐free medium supplemented with dibutyryl adenosine 3′:5′‐cyclic monophosphate (DBcAMP) and basic fibroblast growth factor (bFGF). The suspensions were prepared from dorsal skins of mice exposed to UVB for 4 weeks (the stage of hyperpigmentation). Suspensions were also prepared from mice at 3 (the stage of depigmentation), 8 (the stage of appearance of pigmented spots), 20 (the stage of development of small‐sized pigmented spots) and 37 (the stage of development of medium‐sized pigmented spots) weeks after the cessation of 8‐week UVB exposure. At the stage of hyperpigmentation the proliferative activity of melanoblasts and melanocytes was suppressed. With the development of pigmented spots, the proliferative activity of undifferentiated melanoblasts gradually increased, and then followed the increase in the proliferative activity of differentiated melanocytes. These results suggest that the proliferative activity of epidermal melanoblasts and melanocytes in UVB‐irradiated skin increases with the development of pigmented spots.
New Insights into the Pathogenesis of Vitiligo: Imbalance of Epidermal Cytokines at Sites of Lesions
Authors: Moretti Silvia , Spallanzani Adelina , Amato Lauretta , Hautmann Giuseppe , Gallerani Isabella , Fabiani Massimo , Fabbri Paolo
Published: March 2003

Vitiligo is a skin disease that is caused by selective destruction of melanocytes and is characterized by white spots. Melanocytes and keratinocytes seem to exhibit a functional close relationship, mediated at least in part by keratinocyte‐derived cytokines, which seem important for survival and activity of melanocytic cells. We wanted to investigate the hypothesis that in vitiligo the expression of epidermal cytokines may be modified compared with normal skin. In 15 patients with active, non‐segmental vitiligo, biopsies were obtained from lesional, perilesional and non‐lesional skin; normal skin from five healthy donors was also tested. Tissue sections were tested using immunohistochemistry for the expression of keratinocyte‐derived cytokines with stimulating activity, such as granulocyte–monocyte colony stimulating factor (GM‐CSF), basic fibroblastic growth factor (bFGF), and stem cell factor (SCF) or with inhibiting activity, such as interleukin 6 (IL‐6) and tumour necrosis factor α (TNF‐α) on melanocytes. Cytokine receptors and specific melanocytic markers were also investigated. No melanocyte was identified in lesional skin by means of specific markers or c‐kit receptor, whereas in perilesional, non‐lesional and healthy skin, melanocytes were found in similar number. In vitiligo skin a significantly lower expression of GM‐CSF, bFGF and SCF was found, and a significantly higher expression of IL‐6 and TNF‐α was detected, compared with perilesional, non‐lesional and healthy skin. In conclusion, we provided evidence that a significant change of epidermal cytokines exists in vitiligo skin compared with perilesional, non‐lesional and healthy skin, suggesting that the cytokine production of epidermal microenvironment may be involved in vitiligo.
Agouti Signal Protein Regulation in Human Melanoma Cells
Authors: Voisey Joanne , Kelly Greg , Van Daal Angela
Published: March 2003

Production of the pigment eumelanin is controlled by α‐melanocyte stimulating hormone (α‐MSH) stimulation of melanocortin 1 receptor (Mc1r), whereas production of pheomelanin results from agouti antagonism of α‐MSH signalling through Mc1r. The role of agouti in mouse pigmentation has been extensively investigated but a role for agouti signalling protein (ASIP) in human pigmentation has not been determined. To determine whether ASIP regulates known melanogenic genes in humans, ASIP was over‐expressed in a human melanoma cell line. Levels of mRNA and protein were measured in genes known to be up or down‐regulated by agouti in the mouse, namely microphthalmia (Mitf), tyrosinase (Tyr), tyrosinase‐related protein 1 (Tyrp1), dopachrome tautomerase (Dct), Mc1r, silver, initiation transcription factor 2 (Itf2) and mini chromosome maintenance protein 6 (Mcm6). These melanogenic genes were not found to be significantly up or down‐regulated by ASIP at the transcriptional level in human melanoma cells. However, ASIP down‐regulation of tyrp1 was observed at the translational level. To identify novel genes that may be regulated by ASIP in melanoma cells, microarrays were used to determine differences in gene expression between the control and ASIP transfected melanoma cells. The expression level of human RNAs were determined by microarray analysis using a 19 200 cDNA and a 19 200 oligonucleotide array representing 13 000 and 18 864 individual genes, respectively. Genes observed to be modulated by ASIP were confirmed by quantitative real‐time polymerase chain reaction. Results identify five genes, namely PPARβ, eIF‐4B, RRM2, MINOR and EVI2B that are down‐regulated by ASIP, indicating a likely role for ASIP in human melanogenesis.
Tyrosinase Gene Correction Using Fluorescent Oligonucleotides
Authors: Biet Elodie , Alberti Christophe , Faccella Paolo , Sun Jian Sheng , Dutreix Marie , Larue Lionel
Published: March 2003

Gene therapy and production of mutated cell lines or animal models should be improved significantly once efficient controlled gene targeting strategies are developed. We used short single‐stranded oligodeoxynucleotides (ODN), in some cases coupled to the fluorescent dye fluorescein isothiocyanate (FITC), to correct an endogenic natural point mutation in melanocytes in culture. The addition of the FITC molecule to the 5′ extremity of the ODN did not interfere with the efficiency of the reversion of the mutation and did not have any deleterious side‐effects. The use of fluorescent ODN could lead to great improvement in the technique. In particular, it may facilitate sorting of the transfected cells in the treated population, and thereby significantly increase the percentage of corrected cells.
Cell proliferation and cell death in periodontal ligaments during orthodontic tooth movement
Authors: Mabuchi R. , Matsuzaka K. , Shimono M.
Published: March 2003

The purpose of this study was to investigate cellular responses of periodontal ligaments during tooth movement. Twenty‐eight male Sprague‐Dawley rats, weighing 200–250 g each, were used. To create the orthodontic force, elastic rubber blocks (0.65 mm thick) were inserted between the maxillary first and second molars on both sides. On days 3, 7, 10, 14, 21 and 28 after rubber block insertion, histopathological changes in both the tension and the pressure sides were examined by immunohistochemistry using proliferating cell nuclear antigen (PCNA) and by the TUNEL method. The ratios of PCNA‐positive cells on the tension side 3 and 7 days after rubber block insertion were higher than those on the pressure side. The ratios of PCNA‐positive cells on the tension side were highest at day 3 after insertion and then decreased during the remainder of the experimental period. On the pressure side, the ratios of PCNA‐positive cells increased up to day 10 post insertion, then decreased from 14 to 28 days. The ratios of TUNEL‐positive cells on both the tension and the pressure sides increased throughout the entire experimental period. These results indicate that the periodontal ligaments on the tension side are able to respond more promptly to orthodontic forces than those on the pressure side. The data also suggest that the ratios of cell proliferation and of cell death are closely related to the regeneration and reconstruction of periodontal ligaments which reflect the orthodontic force.