bluuebunny/crossref_metadata_2025 huggingface dataset:
Endothelial, but not the inducible, nitric oxide synthase is detectable in normal and portal hypertensive rats
Authors: Stumm Michael Martin , D'Orazio Daniel , Sumanovski Lazar Trajan , Martin Pierre‐Yves , Reichen Juerg , Sieber Cornel Christian
Published: March 2003

Abstract: Background: Chronic portal hypertension is accompanied by a nitric oxide (NO) dependent vasodilation. Three isoforms of NO producing synthases (NOS) are characterized: neuronal NOS (nNOS), endothelial NOS (eNOS) and inducible NOS (iNOS). Sources of increased NO levels in chronic hypertension is disputed. Methods: To determine eNOS and iNOS expression in different organs of portal hypertensive and control rats, we divided Sprague‐Dawley rats in 6 groups: (1) Partial portal vein ligated rats, (2) Bile duct ligated rats, (3) Carbon tetrachloride treated rats, (4) Sham operated rats, (5) Untreated control rats, and (6) LPS treated rats. Immunohistochemistry (IHC) and immunoblotting (IB) using antibodies against eNOS or iNOS were carried out on samples from thymus, aorta, heart, lung, oesophagus, liver, spleen, kidney, pancreas, small and large intestine. Results: IHC revealed an even eNOS expression in all groups. Expression of iNOS was restricted to macrophages in organs of LPS treated and the thymus of rats. IB mirrored these results. Conclusion: In chronic portal hypertension, the main source for NO production depends on eNOS activity.
Cost‐effectiveness of adjuvant interferon therapy after surgical resection of Hepatitis C‐related hepatocellular carcinoma
Authors: Hoshida Yujin , Shiratori Yasushi , Omata Masao
Published: March 2003

Abstract: Background: To evaluate cost‐effectiveness of adjuvant interferon therapy used with surgical resection of hepatitis C‐related primary hepatocellular carcinoma. Design: We constructed a Markov model that simulated adjuvant interferon therapy after resection of hepatitis C‐related hepatocellular carcinoma, and evaluated life expectancy, costs, and cancer recurrence. The reference case is a 60–year‐old man with hepatitis C‐related compensated cirrhosis. Results: At the baseline, adjuvant interferon therapy yielded 6.1 life years with a cost of $77, 000, and an incremental cost‐effectiveness ratios of $ 15, 700/life year compared with no interferon therapy. The proportion of patients who experienced recurrence of hepatocellular carcinoma until death was reduced from 87.6% to 62.9% using adjuvant interferon therapy. The incidence of recurrent hepatocellular carcinoma after interferon influenced the cost‐effectiveness of adjuvant interferon therapy. A threshold analysis showed that adjuvant interferon therapy was not cost‐effective (ICER = $ 27, 000/year) if the annual incidence of recurrent hepatocellular carcinoma after interferon is 16% (baseline 8.9%). The proportions of patients with recurrent hepatocellular carcinoma were 74.4% and 86.9% at the annual recurrence rates after interferon of 16% and 35%, respectively. Conclusions: Adjuvant interferon therapy after surgical resection of primary hepatitis C‐related hepatocellular carcinoma improves life expectancy through suppression of recurrent cancer with acceptable cost‐effectiveness.
Clinical and histopathological evaluation of 13 cases of adenocarcinoma in aged rhesus macaques (Macaca mulatta)
Authors: Rodriguez N.A. , Garcia K.D. , Fortman J.D. , Hewett T.A. , Bunte R.M. , Bennett B.T.
Published: March 2003

In recent years, the emphasis on aging research, has led to an increase in the number of aged macaques being maintained in some research facilities with a subsequent increase in the occurrence of age‐related diseases. One of the most commonly reported age related diseases is intestinal adenocarcinoma. At the University of Illinois at Chicago (UIC), which maintains a colony of approximately 55 aged rhesus macaques 13 cases of intestinal adenocarcinoma were diagnosed within a 25‐month period. This report provides a comprehensive description of the clinical findings for intestinal adenocarcinoma in aged rhesus macaques, including results from physical examinations, laboratory tests, radiographic evaluations, gross and histopathologic findings as well as a comparison with the disease condition in humans. The use of carcinoembryonic antigen as a potential tumor marker was evaluated by immunohistochemical analysis of tissue specimens in 10 cases. Intestinal adenocarcinoma is a disease condition that should be of concern to individuals responsible for the care of aged rhesus macaques.
Record review of baboons with histologically confirmed endometriosis in a large established colony
Authors: Jr Dick E.J. , Hubbard G.B. , Martin L.J. , Leland M.M.
Published: March 2003

Abstract: Spontaneous endometriosis was diagnosed in 43 baboons over a 14‐year period. Thirty‐seven have died; five remain alive; one was sold and lost to follow‐up. The average age at diagnosis was 17.2 years; 29 (67%) were between 12 and 21 years of age. Fifteen (35%) were diagnosed by biopsy and received surgical excision of the endometriotic tissue; four of these were identified during caesarian section, confirming one prior report of endometriosis in pregnant animals. Twenty‐eight (65%) were diagnosed at or shortly preceding necropsy. When diagnosed by a palpable abdominal mass, there was a significantly greater likelihood the animal died or was killed as a result of complications of endometriosis. When diagnosis was at necropsy, there was a significantly greater likelihood that the animal died from causes unrelated to endometriosis. Early identification with surgical removal appears to provide a benefit for both survival and delivering offspring after diagnosis. In twenty‐one baboons (49%), endometriosis affected multiple sites within the peritoneal cavity. In the remaining baboons, lesions were more localized. Ovarian involvement was seen in sixteen (37%) of these baboons. This paper is the first to describe significant ovarian involvement in baboons, previously considered a limitation of the usefulness of this species as an animal model. We also describe the first reported endometriosis seeding of an abdominal surgery scar in a baboon. Many of these baboons were middle aged, had few or no offspring, or had evidence of a long duration of uninterrupted menstrual cycles, consistent with risk factors for women. Endometriosis was an incidental finding in 17 (40%) of these baboons, consistent with previous reports of minimal endometriosis as a common asymptomatic finding in baboons and in women. Overall, endometriosis in baboons presents a spontaneously occurring animal model that shares important features with the disease in women and the rhesus macaque.
Morphological changes accompanying the partial reduction/re‐oxidation cycles applied to an iron ore
Authors: Ogasawara Tsuneharu , Adamian Rupen
Published: March 2003

This paper is concerned with ironmaking and its purpose is to gain insight into the effect of the partial reduction/re‐oxidation process during sinter making in the resultant ore reducibility. Morphological changes experienced by hematite iron ores during thermal‐chemical treatment of hematite‐to‐magnetite partial reduction, followed by magnetite‐to‐hematite re‐oxidation, were observed by scanning electron microscopy and surface‐area measurements. It was verified that during the partial reduction step, a considerable increase in the surface area occurs, arising from the generation of pores and cracks. During the re‐oxidation step, another significant increase in surface area also occurs, resulting from the nucleation and growth of numerous globules of hematite at the surface of grains. This feature is associated with the iron‐ore sintering process and may contribute to improving the sinter reducibility during the subsequent iron‐making process. Hematite composition: 1.03wt%SiO2, 0.04wt%FeO, 98.2wt% Fe2O3, 0.53wt% Al2O3, 0.03wt% MnO, 0.05wt% Na2O, 0.02wt% K2O, 0.05wt% CaO, and 0.10wt%MgO.
A thermodynamic database for Ni‐base superalloys
Authors: Dupin N. , Sundman B.
Published: March 2003

A thermodynamic database has been developed for Ni‐base superalloys. Following the CALPHAD procedure, it is based on the assessment of thermodynamic behaviour of the relevant constituting sub‐systems of the complex system of interest. The current database contains 7 elements: Al, Co, Cr, Ni, Ti, W, Re. The thermodynamics of the γ and γ′ phases are modelled with a single Gibbs energy function taking into account the crystallographic relation between these two phases. The formalism of the thermodynamic models used is briefly introduced. A few phase diagrams calculated with the current database in assessed binary and ternary systems are presented. Some experiments available in higher order systems are compared with the results of calculations with the current database. The ability of extrapolation of the database is verified for solid state equilibria as well as for solidification behaviour (liquidus temperature and partition ratios). The introduction of Mo and Ta to the current database is in progress. Other elements (Nb, Fe, Zr, Hf, C, B, ···) are planed to be introduced.
Concentration fluctuations induced by thermally‐driven local order changes in the molten binary alloy
Authors: Tsuchiya Y.
Published: March 2003

New universal relations are presented that connect the Darken stability with the constant pressure specific heat and the isothermal compressibility. They are the counterparts of the Ehrenfest‐Pippard relations in an extended form for 2nd‐order phase transitions in binary mixtures. The new relations make it possible that the contribution in the Darken stability caused by structural changes can be evaluated in terms of experimentally‐available thermodynamic response functions. The analysis for the Se‐Te and S‐Te systems shows that thermally‐driven local‐order changes cause segregation tendency on an atomic scale which can be large enough to cause divergent concentration fluctuations in the latter system. The unique closed loop miscibility gap localized in a small x‐T region, some 300 °C above the liquidus line, is a consequence of the change in the local order in the liquid.
Tin solubility in CaO‐bearing slags
Authors: Street Stuart J. , Coley Ken S. , Irons Gordon A.
Published: March 2003

A series of laboratory experiments were undertaken to study the tin (Sn) solubility in lime (CaO) bearing slags. The equilibrium Sn solubility at 1873K was investigated using a gas‐slag‐metal equilibrium technique. Sn solubilities from the high CaO slags are discussed as a function of slag composition and oxygen potential.
Reduction of steel‐making slags for recovery of valuable metals and oxide materials
Authors: Ye Guozhu , Burström Eric , Kuhn Michael , Piret Jacques
Published: March 2003

Extensive researches on slag reduction for recovery of valuable metals and oxide materials from metallurgical slags and other wastes using a DC furnace with a hollow electrode have been conducted in 2 major EU projects with close cooperation between MEFOS, FEhS and CRM. Steel slags and other residues were introduced into the reactor through the hollow electrode to the hot plasma. The materials were melted, reduced and mixed. The final products were a metal product, a slag product with targeted chemical composition and a dust fraction with a high content of ZnO. Different steel‐making slags and residues including BOF slag with low and high V‐content as well as EAF and AOD slags from stainless steel production, EAF dust, oily millscale, hydroxide sludge, BOF and BF dust have been treated. The slag products include a metallurgical powder for desulfurization of steel, hydraulic binder and slag stones for construction applications. The metals obtained are rich in Fe, Mn, V and Cr depending on the treated slag and residues. The environmental compatibility and mechanical properties of the slags have been improved after slag reduction.
Factors influencing community structure in a South American tank bromeliad fauna
Authors: Armbruster Peter , Hutchinson Robert A. , Cotgreave Peter
Published: March 2003

We examined factors influencing the structure of naturally replicated, taxonomically unrestricted communities inhabiting South American tank bromeliads. We measured aspects of plant physical structure and collected the entire macroscopic fauna of 209 bromeliads from the Yasuní Scientific Reserve in lowland eastern Ecuador. We collected a total of 11 219 individuals of 354 morphospecies. The morphospecies abundance distribution of our sample was approximated by a log‐series distribution dominated by rare morphospecies (57% of the morphospecies were represented by a single individual). Six methods for estimating the total number of bromeliad associated morphospecies in our study area gave results which varied by a factor of three, illustrating that caution should be exercised in interpreting the results of any single estimator. Variation in plant volume, number of leaves, detritus content, and water volume explained 62% of the variation in morphospecies richness among plants. Finally, there was a quadratic relationship between body mass and both individual abundance and morphospecies richness in our sample. These results illustrate an important role of both biotic and abiotic factors influencing the structure of taxonomically unrestricted, ecologically defined natural communities.
Intra‐ and interspecific competition among coexisting lotic snails
Authors: Cross Wyatt F. , Benke Arthur C.
Published: March 2003

The competitive interactions of two lotic snails, Elimiacahawbensis and Elimiacarinifera, were examined in a second‐order spring‐fed stream. We first demonstrated food limitation in laboratory microcosms where snails grew faster when exposed to enhanced periphyton levels. We then tested the magnitude and relative strengths of intra‐ and interspecific competition in similar stream and laboratory mesocosm experiments. Treatments were maintained in Plexiglas enclosures over a 7‐week period with 0, 1×, 2× and 4× ambient biomass of each species alone, as well as mixed species treatments at 2× and 4× ambient. Snail responses to treatments were almost identical in field and laboratory experiments. Growth rates of both species were reduced by increased density of snails indicating strong intra‐ and interspecific competition among E.cahawbensis and E.carinifera. An analysis of the strengths of intra‐ and interspecific competition indicated minimal differences for either species, implying a lack of competitive dominance. Although periphyton biomass was generally highest without snails, there was little difference in periphyton biomass and snail production over the four‐fold density range, regardless of species composition. These results suggest that E.cahawbensis and E.carinifera are functionally redundant with density‐dependent responses in growth rate resulting in similar grazing pressure across a density gradient. This clearly demonstrates that species impact is not necessarily reflected by measures of abundance or biomass, and that secondary production should be considered.
Spring migration strategies of two populations of bar‐tailed godwits, Limosa lapponica, in the Wadden Sea: time minimizers or energy minimizers?
Authors: Scheiffarth Gregor , Wahls Svea , Ketzenberg Christiane , Exo Klaus‐Michael
Published: March 2003

Birds can optimize their migration either by minimizing time of transport, energy expenditure, or predation risk during migration. For each of these optimization criteria different fattening and stopover strategies are predicted. The first two of these optimization criteria are examined here for the bar‐tailed godwit (Limosa lapponica). In the European Wadden Sea two populations of bar‐tailed godwits stop over during spring migration between their wintering and breeding areas. The European population winters mainly in Great Britain and the western part of the Wadden Sea and breeds in Fennoscandia. The Afro‐Siberian population winters in West Africa and breeds in Siberia. The European wintering population migrates to the eastern parts of Wadden Sea in March where it stays until early May. During this time birds gain 1.9 g d−1 in body mass for a 1500–2000‐km non‐stop flight to the breeding areas. Afro‐Siberian birds stay only for one month in May in the Wadden Sea where they gain on average 9.4 g d−1 in mass for a 4000‐km non‐stop flight. Intake rates in April/May did not differ between the two populations (1.5 kJ min−1 and 1.8 kJ min−1 for Siberian and European migrants, respectively) but total energy intake was higher for the Siberian migrants, since they spend 50% of the day foraging vs 30% in the European birds. In contrast to European migrants, Afro‐Siberian birds start to moult into breeding plumage already in their winter quarters. During their stopover in the Wadden Sea thermostatic costs are lower than at times when European birds are present. Thus, the higher energy demands of the Afro‐Siberian birds seem to be fulfilled by a combination of physiological adaptations and a high working level. European birds seem to adopt an energy‐minimized migration strategy whereas Afro‐Siberian birds appear to follow a time‐minimized migration.
The role of habitat connectivity and landscape geometry in experimental zooplankton metacommunities
Authors: Forbes Andrew E. , Chase Jonathan M.
Published: March 2003

Theory predicts that inter‐patch dispersal rates and patterns of patch heterogeneity both have the potential to alter patterns of local and regional species diversity. To test this, we manipulated both rates of habitat connectivity and the geometric arrangement of habitat heterogeneity within regions of experimental zooplankton communities. We found no effects of habitat geometry on any metric of species diversity or composition. Additionally, we found no effect of habitat connectivity rate on local species diversity. We did, however, find that increasing connectivity led to a decrease in regional diversity, as well as an increase in the percent similarity of local communities within regions. Of all of the species in these communities, the relatively large cladoceranCeriodaphnia reticulatasignificantly responded to the treatments, and had a higher probability of achieving high densities when connectance was high. As such, we suggest that this species played a large role in driving the increased local community similarity and decreased regional species richness as connectivity increased. These findings are in opposition to previous experimental studies of metacommunities, but support the notion that increased connectance among local patches may decrease regional diversity when patches are heterogeneous.
Artificial climate warming positively affects arbuscular mycorrhizae but decreases soil aggregate water stability in an annual grassland
Authors: Rillig Matthias C. , Wright Sara F. , Shaw M. Rebecca , Field Christopher B.
Published: March 2003

Despite the importance of arbuscular mycorrhizae to the functioning of terrestrial ecosystems (e.g. nutrient uptake, soil aggregation), and the increasing evidence of global warming, responses of arbuscular mycorrhizal fungi (AMF) to climate warming are poorly understood. In a field experiment using infrared heaters, we found effects of warming on AMF after one growing season in an annual grassland, in the absence of any effects on measured root parameters (weight, length, average diameter). AMF soil hyphal length was increased by over 40% in the warmed plots, accompanied by a strong trend for AMF root colonization increase. In the following year, root weight was again not significantly changed, and AMF root colonization increased significantly in the warmed plots. Concentration of the soil protein glomalin, a glycoprotein produced by AMF hyphae with importance in soil aggregation, was decreased in the warmed plots. Soil aggregate water stability, measured for five diameter size classes, was also decreased significantly. In the following year, soil aggregate weight in two size classes was decreased significantly, but the effect size was very small. These results indicate that ecosystem warming may have stimulated carbon allocation to AMF. Other factors either influenced glomalin decomposition or production, hence influencing the role of these symbionts in soil aggregation. The observed small changes in soil aggregation, if widespread among terrestrial ecosystems, could have important consequences for soil carbon storage and erosion in a warmed climate, especially if there are cumulative effects of warming.
Facilitation versus competition in grazing herbivore assemblages
Authors: Arsenault Randal , Owen‐Smith Norman
Published: March 2003

The importance of facilitation versus competition in structuring herbivore species assemblages is a critical issue in theoretical ecology as well as for practical wildlife management. This paper examines the evidence for facilitation and clarifies our understanding in relation to the mechanisms and the spatial and temporal scales where they occur. Evidence for facilitation through stimulation of grass regrowth during the growing season appears stronger than that for increased resource access through removal of obstructing grass structures during the dormant season. Although facilitation may benefit the nutritional gains obtained by certain species in the short term, these benefits do not appear to be translated into the expected population consequences. We suggest this could be due to seasonal tradeoffs between facilitation and competition, as well as to restrictions on the spatial extent of trophic overlap.
A proximate model for thermal tolerance in ectotherms
Authors: Van Der Have T. M.
Published: March 2003

Thermal limits of viable ectotherm development are threshold‐like and near‐symmetrical around the temperature of optimal performance and usually well within the thermal tolerance range of adult physiological traits. A proximate model is proposed to show that the interaction between reversible temperature inactivation of cell cycle proteins and their regulation can explain (1) the symmetry and (2) threshold character of thermal limits of viable embryonal and larval development in ectotherms. It is suggested that temperature inactivation of regulatory proteins mimics the decrease in concentration resulting from gene dosage change and transcriptional regulation during the cell cycle. If certain regulatory proteins have equal probability to be active or inactive at a certain temperature, cell division and, consequently, development becomes blocked. Model predictions were tested by comparing thermal tolerance limits as observed in viability experiments with 14 developing insect species with the estimated temperatures at which a hypothetical rate‐determining developmental enzyme has an equal probability to be active or inactive. These ‘expected’ thermal limits were derived from the Sharpe‐Schoolfield equation which describes temperature–differentiation rate reaction norms. In 21 out of 23 comparisons ‘expected’ thermal limits agree closely with the observed thermal tolerance limits. The implications of the model for thermal tolerance, thermal adaptation, epidemiology and life‐history strategies are discussed.
Metapopulation persistence in dynamic landscapes: the role of dispersal distance
Authors: Johst Karin , Brandl Roland , Eber Sabine
Published: March 2003

Species associated with transient habitats need efficient dispersal strategies to ensure their regional survival. Using a spatially explicit metapopulation model, we studied the effect of the dispersal range on the persistence of a metapopulation as a function of the local population and landscape dynamics (including habitat patch destruction and subsequent regeneration). Our results show that the impact of the dispersal range depends on both the local population and patch growth. This is due to interactions between dispersal and the dynamics of patches and populations via the number of potential dispersers. In general, long‐range dispersal had a positive effect on persistence in a dynamic landscape compared to short‐range dispersal. Long‐range dispersal increases the number of couplings between the patches and thus the colonisation of regenerated patches. However, long‐range dispersal lost its advantage for long‐term persistence when the number of potential dispersers was low due to small population growth rates and/or small patch growth rates. Its advantage also disappeared with complex local population dynamics and in a landscape with clumped patch distribution.
Functional significance of crayfish in stream food webs: roles of omnivory, substrate heterogeneity and sex
Authors: Usio Nisikawa , Townsend Colin R.
Published: March 2003

Heterogeneity of species interactions in food webs can result from characteristics of substrates as well as attributes of top consumers. We performed a streamside channel experiment to evaluate the impact of crayfish on lower trophic levels in detritus‐based (leaf packs) and algal‐based food webs (hard‐bottoms). After 43 days, both male and female crayfish had dramatically promoted leaf decomposition, with males processing material at a faster rate. However, the difference in leaf processing rates was not related to a greater level of male activity. Despite the sex‐related difference in residual leaf dry mass, densities of invertebrates in leaf packs were similarly low in the presence of crayfish of either sex, due to resource consumption, physical dislodgment (bioturbation) and/or predation. No trophic cascade was evident in the leaf pack assemblage. In the hard‐bottom assemblage, the results confirmed circumstantial field evidence that crayfish reduce predatory Tanypodinae and indirectly increase collector‐gatherer Chironominae following the prediction of a trophic cascade. However, no other taxa were indirectly facilitated, because of strong direct effects of crayfish on algal abundance (through direct consumption and bioturbation). Overall, impacts of crayfish on lower trophic levels were more pronounced in the structurally complex, detritus‐based assemblages than in its hard‐bottom, algal‐based counterpart. This conflicts with the expectation that net predation effects should be weaker where structural complexity is greater but is mainly a consequence of the profound engineering effects of crayfish in reducing colonisable substrate when they shred and disturb detrital material. Effects of crayfish may therefore propagate differently and with varying strength depending on substrate. Moreover, engineering activities and predation by crayfish appear to have been of overwhelming significance with subtle sex differences in leaf processing rates failing to lead to differences in invertebrate densities.
Ultimate and proximate factors affecting the breeding performance of a marine top‐predator
Authors: Pinaud David , Weimerskirch Henri
Published: March 2003

Variability in ecosystems affects the life history of organisms. In marine ecosystems where interannual variability is high, relationships between fluctuations in oceanographic parameters and top‐predator breeding performance are increasingly documented but it is less clear why such relationships exist. In this study, we examined the connections between marine environment fluctuations and breeding performance of a long‐lived top‐predator, the black‐browed albatross Diomedea melanophris at Kerguelen, through study of resource acquisition and allocation processes. Our results show that this population used the same foraging zones and spent similar time foraging year after year, but adult body condition varied between years. Foraging trips are regulated mainly by changes in body condition. During years of low resource availability, birds return to their nest with lower body condition and adults in low body condition were more frequent and therefore were more likely to stop breeding. Poor breeding success was related to the presence of colder waters in the foraging zones of breeding albatrosses as measured by the positive correlation between sea surface temperatures and breeding success measured over 18 years. Lower breeding success was mainly due to failure by inexperienced birds. The results of this study demonstrate how oceanographic conditions affect breeding performance through allocation processes. We compared these results to those at South Georgia where the breeding success is lower and more variable. This population relies mainly on krill, a resource that shows a very variable year‐to‐year availability compared to fish prey consumed by Kerguelen birds. This study shows that, in the same species, differences in resource variability and availability affect the demographic strategies probably through differences in allocation strategies.
The combined effect of environmental factors and neighbouring populations on the distribution and abundance ofArvicola terrestris.An approach using rule‐based models
Authors: Bonesi Laura , Rushton Steve , Macdonald David
Published: March 2003

We investigated how the interplay between environmental factors and presence of neighbouring populations determines the distribution and abundance of a small, endangered rodent, the water vole (Arvicola terrestris). We studied thriving and non‐fragmented populations of water voles in the absence of their main predator, the introduced American mink (Mustela vison). A low degree of population fragmentation, such as the one characterizing the studied populations, was probably typical of water voles before their decline started. We found that under these conditions water voles’ distribution is mainly determined by three environmental factors: presence of freshwater, adequate food, and cover. Variance in other factors is well tolerated by water voles. We obtained this result by the use of rule‐based models in two separate areas. The two models correctly classified 81% and 83% of the observed cases, respectively. When optimised on one area and cross‐validated on the other area the performance of the models was still high (73% and 79%) indicating that the models were robust and generalizable. We also found that the density of animals was lower in sub‐optimal than in optimal habitat. We then tested the hypothesis that the number of neighbouring colonies determines the probability of finding voles in a given section. We found that the presence of nearby colonies was an important factor in determining the presence of water voles in sub‐optimal habitat, while isolated patches of suitable habitat were less likely to host water voles. These observations suggest the possible presence of a source‐sink dynamic, where an optimal habitat acts as a source for populating sub‐optimal habitats that may be considered a sink habitat. These findings are discussed in the context of water vole conservation.
Climatic flowering requirements of bipolar sedges, Carex spp., and the feasibility of their trans‐equatorial migration by mountain‐hopping
Authors: Heide Ola M.
Published: March 2003

A selection of northern and southern hemisphere populations of a range of bipolar Carex species was grown in controlled environments for comparison of their temperature and daylength requirements for flowering. All studied species have basically the same dual induction requirements for flowering but differ quantitatively in their respective critical temperatures and daylengths for primary and secondary floral induction. Usually, low temperature or short days (SD), over a wider range of temperatures, were required for initiation of inflorescence primordia, whereas long days (LD) advanced but were not obligatory for heading and flower development. It is concluded that no change or adaptation in the flowering requirements would have been necessary for these plants to migrate across the tropics and their penetration into the southern hemisphere by mountain‐hopping. The flowering requirements of these and a range of other bipolar plant species are compatible with the hypothesis that absence of an obligatory long day floral induction requirement has facilitated or been a prerequisite for trans‐equatorial migration of plants by mountain‐hopping and the establishment of bipolar species distributions.
Clear cell odontogenic tumor in the mandible: report of a case with duct‐like appearances and dentinoid induction
Authors: Kumamoto Hiroyuki , Yamazaki Shinji , Sato Atsushi , Yamaguchi Tai , Tezuka Fumiaki , Ooya Kiyoshi
Published: March 2003

Abstract: A case of clear cell odontogenic tumor with unusual histological features is presented. A 61‐year‐old Japanese man was admitted because of swelling of the left premolar‐molar region of the mandible. Radiological examination revealed a multilocular radiolucency with irregular margins. Histological examination of the resected specimen showed infiltrative proliferation of both clear and eosinophilic cells into the adjacent soft tissue without encapsulation, suggesting the malignant potential of the tumor. The tumor cells sporadically formed cystic lesions. In addition, several tumor cell nests showed duct‐like characteristics, and many eosinophilic dentin‐like structures were attached to the tumor cell nests, suggesting the potential for epithelial‐mesenchymal induction. Histochemically, the clear tumor cells possessed cytoplasmic glycogen granules. Both clear and eosinophilic tumor cells showed positive immunoreactivities for cytokeratin 19, epithelial membrane antigen and filaggrin, indicating an odontogenic epithelial origin.
Dissemination of cancer cells into circulation occurs by incisional biopsy of oral squamous cell carcinoma
Authors: Kusukawa Jingo , Suefuji Yuichi , Ryu Fuminori , Noguchi Ryo , Iwamoto Osamu , Kameyama Tadamitsu
Published: March 2003

Abstract: To examine whether cancer cell dissemination results from incisional biopsy, we tried to detect squamous cell carcinoma (SCC) cells in peripheral blood before and after incisional biopsy by means of cytokeratin 19 (CK19) reverse‐transcriptase polymerase chain reaction (RT‐PCR). The study population consisted of 20 patients with oral SCC; 10 were given incisional biopsies followed by radical excision (the incisional biopsy group), and the remaining 10 were treated by excisional biopsy alone (the excisional biopsy group). Ten non‐oral cancer patients with benign oral lesions served as controls. Five‐ml blood aspirates collected before and after incision were used for CK19 RT‐PCR. Two (20.0%) of 10 patients from the incisional biopsy group were positive for CK19 transcripts in their peripheral blood drained 15 min after incision. In contrast, CK19 transcript was not detected either in the excisional biopsy group or in controls. Surgical invasiveness for oral cancer, including incisional biopsy, causes dissemination of cancer cells into circulation, resulting in increased risk of metastasis.
Gingival and cutaneous angiosarcoma
Authors: Abdullah Bashar H. , Yahya Hassan I. , Talabani Nazar A. , Alash Nawal I. , Mirza Khalid B.
Published: March 2003

Abstract: Multiple oral and cutaneous nodular and papular reddish‐blue lesions are described in the case of a 60‐year‐old woman. The duration of the lesions was more than 1 year, with the oral lesion preceding the skin lesions. Histopathological examination revealed malignant vascular tumour with changes consistent with angiosarcoma. Angiosarcoma is an extremely rare malignant tumour of the oral cavity, and the present case describes oral and skin lesions with a unique clinical behaviour.
Non‐specific influx of T‐cell receptor alpha/beta and gamma/delta lymphocytes in mucosal biopsies from a patient with orofacial granulomatosis
Authors: Facchetti F. , Signorini S. , Majorana A. , Manganoni M. A. , Sapelli P. , Imberti L.
Published: March 2003

Abstract: Orofacial granulomatosis (OFG) represents an inflammatory disorder of the facial and oral mucosa, histologically characterized by non‐caseating epithelioid cell granulomas. Since other granulomatous diseases have been shown to be characterized by a limited heterogeneity of alpha/beta and gamma/delta T cells, we investigated the T‐cell diversity of both types of lymphocytes obtained from the same OFG patient. When we compared the T‐cell receptor diversity of the lymphocytes accumulating at the site of the lesions with that of the peripheral blood counterpart, we did not find significant differences. Furthermore, no exclusive expansions of different T‐cell clones were seen in the patient. From these data we conclude that, in this OFG patient, the majority of T cells have no specificity for a single or for a few antigens and that tissue accumulation of T lymphocytes is the result of a random influx of cells at the site of inflammation.
MDM2 expression in areca quid chewing‐associated oral squamous cell carcinomas in Taiwan
Authors: Huang Jehn‐Shyun , Ho Tse‐Jung , Chiang Chun‐Pin , Kok Sang‐Heng , Kuo Ying‐Shiung , Kuo Mark Yen‐Ping
Published: March 2003

Abstract: MDM2 (murine double minute gene 2) overexpression has been implicated in the pathogenesis of human tumors via inhibition of the p53 tumor suppressor protein. To investigate the potential involvement of MDM2 overexpression in the pathogenesis of oral squamous cell carcinomas (SCCs) in Taiwan, we examined the expression of MDM2 protein and its relationship to p53 protein levels in 52 oral SCCs using antibodies to MDM2 and p53. Of the 52 patients, 36 (69 %) had tumors with positive MDM2 nuclear staining and 32 (61%) had tumors with p53 nuclear staining. Co‐expression of MDM2 protein and p53 was detected in 25 (48%) cases; and 9 (17%) tumors showed neither MDM2 protein nor p53 staining. A significant correlation was observed between MDM2 protein and p53 expression in 38 cases with an areca quid (AQ) chewing habit (P=0.032). No significant correlation was found between the degree of MDM2 protein staining and the patients’ ages, sex, cancer location, clinical staging, primary tumor TNM status or histological differentiation of SCC at the time of initial presentation. Kaplan‐Meier analysis showed that either MDM2 protein expression or co‐expression of p53 and MDM2 protein did not relate significantly to patient overall survival. Nevertheless, the high prevalence of MDM2 protein overexpression found in this study suggest that MDM2 may also participate in the carcinogenesis of AQ chewing‐associated oral SCCs in Taiwan.
Glandular odontogenic cyst: absence of PTCH gene mutation
Authors: Barreto Diele Carine , Marco Luiz , Castro Wagner Henriques , Gomez Ricardo Santiago
Published: March 2003

Abstract: Glandular odontogenic cyst (GOC) is a rare jawbone cyst of odontogenic origin. Human patched (PTCH) is a tumour suppressor gene that has been recently associated with signalling pathways during odontogenesis. Recently alterations of this gene were found on sporadic odontogenic keratocysts. This evidence, together with the biological behaviour similarities of both lesions, and the absence of reports on molecular analysis of GOC, led us to hypothesize that PTCH gene mutations may underlie the tumorigenesis of GOC. Therefore the aim of this study was to report one additional case of GOC and investigate the PTCH gene of the cyst. No mutations were found in the splicing and coding regions of the PTCH gene. In conclusion, the PTCH gene does not seem to be involved in GOC pathogenesis.
Risk factors associated with oral lesions in HIV‐infected heterosexual people and intravenous drug users in Thailand
Authors: Nittayananta Wipawee , Chanowanna Nilnara , Sripatanakul Sasithorn , Winn Than
Published: March 2003

Abstract: This study aimed to identify factors associated with the presence of oral lesions in HIV‐infected individuals in Thailand, to determine the influence of gender and route of HIV transmission on the prevalence of the lesions, and to investigate whether total lymphocyte cell counts can be used as a serologic marker to predict the occurrence of oral lesions. Two hundred and seventy‐eight HIV‐infected heterosexual persons and intravenous drug users (IVDUs) were enrolled (230 males, 48 females). Eighty‐six HIV‐free subjects from the same population were included as controls (61 males, 25 females). Oral candidiasis was the most common oral lesion among HIV‐infected individuals (39.6%), followed by hairy leukoplakia (HL) (26.3%), exfoliative cheilitis (18.3%), and linear gingival erythema (LGE) (11.5%). Odds ratios (ORs) for factors associated with the presence of oral lesions were as follows for advanced HIV disease defined by clinical status: symptomatic stage [OR=18.6; 95% confidence interval (CI) 7.3–47.2], AIDS stage [OR 7.3; 95% CI 3.4–15.7] and laboratory investigation of total number of lymphocyte cell counts of 1000–2000 cell/mm3[OR 2.7; 95% CI 1.4–5.1] and <1000 cell/mm3[OR 4.0; 95% CI 2.3–7.0], alcohol consumption [OR 3.4; 95% CI 1.3–9.1], and poor oral health [OR 1.7; 95% CI 1.0–2.9]. Men were significantly more likely to have oral lesions than women. No statistically significant difference in the presence of oral lesions was observed between heterosexuals and IVDUs. This study should help predict the risk of acquiring various types of oral lesions, given that the person is exposed to multiple risk factors compared to another who is not exposed to these factors.
Urachal carcinoma with metastasis to the maxilla: the first reported case
Authors: Bastian H. L. , Jensen Eva K. , Jylling A. M. B.
Published: March 2003

Abstract: A case is reported for the first time of a urachal carcinoma with metastasis to the maxilla. The patient presented with a hard swelling along the left upper jaw in the region of 24–27. At the time of onset there were skin changes and signs of metastasis to the brain. The patient died 13 months after the onset of symptoms.
Detection of human papillomavirus DNA in benign oral squamous epithelial lesions in Venezuela
Authors: Jimenez C. , Correnti M. , Salma N. , Cavazza M. E. , Perrone M.
Published: March 2003

Abstract: The polymerase chain reaction (PCR) was applied to the detection of human papillomavirus (HPV) infection in biopsies taken from clinically normal oral mucosa of 20 subjects and clinical lesions of 40 patients. PCR for HPV‐DNA amplification was performed using consensus primers MYO9/MYO11 and subsequent typing for HPV of high and low oncogenic risk HPV types were identified by restriction enzyme analysis (restriction fragment length polymorphism, RFLP). The HPV viral genome was present in 55% (22/40) of the oral benign lesions (OBL) and in 10% (2/20) of the control samples. In the PCR+ OBL, we observed 90.9% of low oncogenic risk types (HPV‐6 ‐13 and ‐32) and 9.1% of the samples had a mixed infection with low and high oncogenic types (HPV‐6 and ‐16). ln the control samples, we observed one patient with HPV‐6 and another with HPV‐6 and ‐16 in the same sample. All of the eight focal epithelial hyperplasia cases were positive for low risk HPV types (88% HPV‐13 and 12.5% HPV‐32). In conclusion, this study demonstrates a high incidence of HPV in oral benign lesions from Venezuelan patients.
A case of submandibular malignant rhabdoid tumor transformed from papillary thyroid carcinoma
Authors: Sumida Tomoki , Hamakawa Hiroyuki , Imaoka Misako , Okamoto Noriko , Takarada Manabu , Tanioka Hiroaki , Ueda Norifumi , Nose Masato
Published: March 2003

Abstract: Malignant rhabdoid tumor (MRT) in the neck region is very rare. We report a case of MRT in a 60‐year‐old woman who had a history of papillary carcinoma of the thyroid gland 7 years previously. One year before admission, in 1995, thyroid carcinoma recurred, and the tumor contained a small undifferentiated region with rhabdoid features. The tumor in 1996 consisted of round to oval rhabdoid cells with abundant cytoplasm, and the growth pattern was diffuse and infiltrative, with no papillary structures. We therefore concluded that the lesion was MRT, transformed from papillary thyroid carcinoma.
Altered cytokeratin expression during chemoprevention of experimental hamster buccal pouch carcinogenesis by garlic
Authors: Balasenthil S. , Rao K. S. , Nagini S.
Published: March 2003

Background: Cytokeratins (also known as keratins (K)) are members of the family of intermediate filaments and form major components of the mammalian epithelial cell cytoskeleton. Cytokeratins have emerged as reliable cellular markers of oral cancer development and chemoprevention because of their abundance, stability and high antigenicity.

Methods: We investigated the effect of aqueous garlic extract on cytokeratin expression during 7,12‐dimethylbenz[a]anthracene (DMBA)‐induced hamster buccal pouch (HBP) carcinogenesis. Hamsters were divided into four groups of six animals. Animals in group 1 were painted with a 0.5% solution of DMBA in liquid paraffin, on the right buccal pouches, three times a week for 14 weeks. Group 2 animals were painted with DMBA as in group 1 and also received 250 mg/kg body weight aqueous garlic extract orally on alternate days to the DMBA application. Group 3 animals received garlic extract only, as in group 2. Group 4 animals received neither DMBA nor garlic extract and served as the control. The hamsters were killed after an experimental period of 14 weeks.

Results: Cytokeratin expression was studied using human monoclonal antibodies AE1 and AE3, which react with type I and II keratins. In DMBA‐induced squamous cell carcinomas, decreased expression of high molecular weight keratins was observed. Administration of garlic extract to animals painted with DMBA suppressed HBP carcinomas and restored normal cytokeratin expression.

Conclusion: The results of the present study suggest that inhibition of HBP carcinogenesis by garlic may be due to its regulatory effects on differentiation, tumour invasiveness, migratory and metastatic potential. We suggest that one of the mechanisms of tumour inhibition by garlic is an influence on cellular differentiation.
Burning mouth syndrome (BMS): double blind controlled study of alpha‐lipoic acid (thioctic acid) therapy
Authors: Femiano F. , Scully C.
Published: March 2003

Background: Burning mouth syndrome (BMS) has features of a neuropathy and could be related to the production of the toxic free radicals that are released in stress situations. Alpha‐lipoic acid is an antioxidant able to increase the levels of intracellular glutathione and eliminate free radicals. This study aimed to examine the effectiveness of alpha‐lipoic acid in the therapy of BMS.

Method: This was a double blind, controlled study conducted for two months on 60 patients with constant BMS. Comparing alpha‐lipoic acid (test) with cellulose starch (placebo), there was no laboratory evidence of deficiencies in iron, vitamins or thyroid function and no hyperglycaemia.

Results and Conclusion: Following treatment with alpha‐lipoic acid, there was a significant symptomatic improvement, compared with placebo, with the majority showing at least some improvement after 2 months, thus supporting the hypothesis that burning mouth syndrome is a neuropathy. This improvement was maintained in over 70% of patients at the 1 year follow‐up.