bluuebunny/crossref_metadata_2025 huggingface dataset:
Acute obstructive cholangiopathy in interleukin‐6 deficient mice: compensation by leukemia inhibitory factor (LIF) suggests importance of gp‐130 signaling in the ductular reaction
Authors: Liu Zejin , Sakamoto Toshiki , Yokomuro Shigeki , Ezure Tsukasa , Subbotin Vladimir , Murase Noriko , Contrucci Sarah , Demetris Anthony J.
Published: March 2003

Abstract: Aim: The hypothesis that interleukin‐6‐IL‐6/gp130 signaling is involved in liver and biliary epithelial cell (BEC) biology and growth control was tested by subjecting homozygous IL‐6 deficient mice (IL‐6−/−) and wild type (IL‐6+/+) littermate controls to bile duct ligation (BDL). Materials and methods: During the first week after BDL, the two groups were compared with respect to routine liver injury tests, liver histology, BEC and hepatocyte DNA synthesis, together with the expression of mRNA and protein of IL‐6 as well as related growth factors, and their receptors. Results: During the first week after BDL, there was marked upregulation of IL‐6 mRNA and protein in the IL‐6+/+ mice only in the vicinity of the biliary tree; whereas, biliary/peri‐biliary IL‐6R, HGF and met mRNA and protein increased in both groups. IL‐6, HGF mRNA and protein localized to periductal inflammatory cells and stellate cells, while met and IL‐6R protein were upregulated in the BEC and, to a lesser extent, in hepatocytes. This occurred during maximal proliferation of the BEC. Despite the absence of IL‐6 in the IL‐6−/− mice, there were only mildly phenotypic differences between the two groups, and no differences in mortality. Compared to IL‐6+/+ controls, IL‐6−/− mice showed slightly less BEC proliferation, a trend toward more liver injury, and significantly higher total serum bilirubin (TB) levels, suggestive of impaired biliary tree integrity. These changes were associated with slightly less HGF mRNA and protein expression in the IL‐6−/− mice, but the differences were not significant. Leukemia inhibitory factor (LIF), another gp‐130 ligand, also showed marked peri‐biliary upregulation after BDL in both groups, and also induced BEC DNA synthesis, in vitro. Conclusions: The mild phenotypical differences between IL‐6+/+ and IL‐6−/− mice in the acute response to BDL is most likely attributable to the redundancy of the gp‐130 signaling system. However, the long‐term response to BDL results in a distinct phenotype in the IL‐6−/− mice, marked by a relentless rise in serum total bilirubin and an inability to maintain compensatory increase in liver mass.
Liver‐infiltrating CD56 positive T lymphocytes in hepatitis C virus infection
Authors: Yonekura Kenji , Ichida Takafumi , Sato Kazunari , Yamagiwa Satoshi , Uchida Moriaki , Sugahara Satoshi , Ito Shinichi , Abo Toru , Asakura Hitoshi
Published: March 2003

Abstract: Aim: Hepatitis C virus (HCV) is a major cause of post‐transfusional and sporadic hepatitis, and leads to chronic liver disease. It has been suggested that virus‐specific cytotoxic T lymphocytes are responsible for liver injuries that occur in HCV‐infected patients. However, the detailed characteristics of these lymphocytes have not yet been defined. We have previously reported that CD56+ T lymphocytes, as intermediates between natural killer cell and T lymphocytes, predominantly infiltrated the liver and were increased in patients with chronic hepatitis related to HCV (CH‐C). Material and Methods: We obtained peripheral blood and liver tissues from 32 patients diagnosed as having CH‐C, and 10 other liver disease patients (5 chronic hepatitis related to HBV, 5 alcoholics), and analyzed peripheral blood and liver‐infiltrating lymphocytes using flow cytometric and immunohistochemical techniques. Results: The CD56+ T lymphocyte ratio in the liver of patients with a high histology activity index (HAI) score for chronic hepatitis was higher than that of patients with a low HAI score and patients with other liver diseases. In addition, T lymphocytes from patients with chronic hepatitis with a high HAI score carried mostly γδ‐TCR. There was a correlation between the ratio of CH‐C and serum alanine aminotransferase, category I (periportal inflammation and necrosis), and IV (fibrosis) of the HAI scoring system. The ratio was highest in zone 1 of the hepatic lobules. Conclusion: The correlation between CD56+ T lymphocyte ratios and hepatocellular damage was examined. These findings suggest strongly that liver‐infiltrating CD56+ T lymphocytes play an important pathologic role in hepatocellular injury in CH‐C.
Nitric oxide and the liver
Authors: Farzaneh‐Far Ramin , Moore Kevin
Published: March 2003

Abstract: In recent years, the role of nitric oxide (NO) in the pathogenesis of liver disease and its complications has been extensively studied. There remain, however, many areas of controversy. In particular, the effect of NO on vascular function in the systemic circulation and the hepatic microcirculation has received the greatest attention. It has been proposed on the one hand that increased NO synthesis is responsible for the development of the hyperdynamic circulation in cirrhosis, while decreased production of NO within the hepatic microcirculation may be important in the development of parenchymal tissue damage and the onset of portal hypertension. The purpose of this review is to examine the available data concerning the role of NO in liver disease and to discuss some of the controversies and contradictions that surround it.
Molecular mimicry and autoimmune liver disease: virtuous intentions, malign consequences
Authors: Bogdanos Dimitrios‐Petrou , Choudhuri Kaushik , Vergani Diego
Published: March 2003

Abstract: The pathogenesis of autoimmune liver disease and autoimmunity associated with chronic viral hepatitis remains poorly understood. One of the major hurdles to a deeper understanding of these pathological processes is the absence of clearly defined inductive mechanisms, which, if identified and characterised, could guide clinical strategies for their prevention or allow therapeutic intervention. Molecular mimicry leading to crossreactive autoimmune responses has gained strong experimental support in the past decade. A fundamental premise of this hypothesis is the involvement of a mimicking environmental trigger. In view of the numerous viral and bacterial agents epidemiologically linked to autoimmune liver diseases, we and others have proposed molecular mimicry to be an important mechanism in these diseases. We also propose similar crossreactive mechanisms to operate in the generation of autoimmunity in viral hepatitis. This review focuses on molecular mimicry at the level of the B‐cell, as few data on T‐cell crossreactivity in liver disease are thus far available.
Chronic hepatitis C and superimposed nonalcoholic fatty liver disease
Authors: Ong Janus P. , Younossi Zobair M. , Speer Christian , Olano Arrel , Gramlich Terry , Boparai Navdeep
Published: March 2003

Abstract: Background/Aims: Hepatitis C and nonalcoholic fatty liver disease (NAFL) are the two most common forms of liver disease in the United States. Recently, obesity and its associated risk factors have been suggested to enhance HCV‐related fibrosis. The aim of this study was to assess the impact of hepatic steatosis, steatohepatitis, and its associated risk factors on HCV‐related fibrosis. Methods: Patients with untreated, biopsy‐proven, chronic hepatitis C (6/97–3/99) were included. Clinical and demographic data at the time of liver biopsy were obtained from chart review and verified by telephone survey. One hepatopathologist reviewed all pathologic specimens, using the modified histological activity index score and the Ishak staging for fibrosis and a NAFL pathologic protocol. Results: One hundred and seventy patients with hepatitis C were included [age: 48.7±9.33 (years), body mass index (BMI): 28.1±5.7 (kg/m2) and type 2 diabetes mellitus (DM): 14%]. Of these, 77 (45.3%) had no or mild fibrosis and 93 (54.7%) had advanced fibrosis. Hepatic steatosis was seen in 90 (52.9%) patients. The grade of steatosis was associated with markers of obesity only. Age (p=0.002), type 2 DM (p=0.04), and superimposed steatohepatitis (p=0.047) were independently associated with advanced fibrosis. Superimposed nonalcoholic steatohepatitis (NASH) was seen in 17 (10%) patients. Patients with superimposed NASH were mostly obese (76.5%), males (62%) with 16% having type 2 diabetes and a BMI 33.8±7.12. Conclusion: In patients with chronic hepatitis C, type 2 DM and superimposed steatohepatitis are independently associated with advanced fibrosis.
Inclusion body myositis associated with hepatitis C virus infection
Authors: Kase Satoru , Shiota Goshi , Fujii Yoko , Okamoto Kinya , Oyama Kenji , Nakano Toshiya , Nomura Takashi , Suou Takeaki , Nakashima Kenji , Ito Hisao , Kawasaki Hironaka
Published: March 2003

Abstract: The case of a 77‐year‐old woman with hepatitis C virus infection with a 5‐year history of muscle weakness and mild disturbance of gait is reported. Steroid therapy did not improve her symptoms. She developed HCV‐related liver cirrhosis and hepatocellular carcinoma, and muscle biopsy revealed inclusion body myositis. Immunohistochemistry showed that the nonstructural region of HCV and 8‐hydroxy‐2′‐deoxyguanosine, a marker of DNA damage by reactive oxygen species, were present in striated muscle cells of this patient.
ABO blood groups in the primate species of Cebidae from the Amazon region
Authors: Corvelo T.C.O. , Schneider H. , Harada M.L.
Published: March 2003

The ABO blood groups were determined in blood and saliva collected from 40 Aotus infulatus, 74 Saimiri sciureus, and 96 Cebus apella from the Amazonian region along the Tocantins river. Saliva samples were tested for human ABH antigens by a standard hemagglutination inhibition test. Aotus infulatus showed monomorphism, exhibiting only the B blood group. Saimiri sciureus exhibited the A (67) and AB (7) phenotypes. All four phenotypes have been found in C. apella: O (8), A (52), B (19) and AB (17). The observed distribution was as expected assuming Hardy–Weinberg equilibrium. The titers of ABH substances varied among the species and phenotypes. The B‐like agglutinogen, common to all New World monkey species tested, was detected in the red blood cells. Sera were used to detect naturally occurring antibodies and the results showed discrepancies between serum and saliva phenotypes in all species studied.
Fatal infection with human pinworm, Enterobius vermicularis, in a captive chimpanzee
Authors: Murata K. , Hasegawa H. , Nakano T. , Noda A. , Yanai T.
Published: March 2003

A fatal infection with human pinworms, Enterobius vermicularis, was found in a 26‐year‐old chimpanzee kept in a zoo. Grossly, the animal was highly emaciated, and had severe enteritis with cecal multifocal nodules and severe cholelithiasis. Histopathologically, a large number of human pinworms were observed in the nodular lesions in the cecum and intestinal wall. These migrating worms were surrounded by an inflammatory cell infiltration which lacked eosinophils. There were areas of multifocal hyperemia and/or hemorrhages in various organs including the entire gastrointestinal tract. Pinworms were also observed in the portal venule and parenchyma of the liver. A light infection with Strongyloides cf. stercoralis was also observed.
Two cases of digital defects in Macaca mulatta infants and a survey of the literature
Authors: Brignolo L. , Tarara R. , Peterson P.E. , Hendrickx A.G.
Published: March 2003

Although congenital digital defects, particularly polydactyly, have been reported frequently in humans, their occurrence in rhesus macaques is relatively rare. We observed two cases of spontaneous digital defects in male rhesus monkey infants recently born at the California Regional Primate Research Center. One infant exhibited bilateral postaxial polydactyly and the other infant had bilateral oligodactyly with unilateral phalangeal duplication. In this report, we present the clinical/pathological details of these cases as well as discuss the embryology of normal and abnormal limb development. We will also summarize a variety of spontaneous and experimentally induced digital defects that have been reported in several nonhuman primate species.
Immune responses in baboons vaccinated with HIV‐2 genetic expression libraries
Authors: Locher C.P. , Sykes K.F. , Blackbourn D.J. , Johnston S.A.
Published: March 2003

Abstract: Immunization using genetic expression libraries may be an improvement over conventional DNA immunization using a single gene because more epitopes are simultaneously presented to the immune system. In this study, we evaluated the effectiveness of an HIV‐2 vaccine made from a genomic expression library in baboons. We found that HIV‐2 expression library immunization induced HIV‐2‐specific memory responses but low levels of CD8+ cell anti‐viral responses and neutralizing antibodies. After intravenous virus challenge using a homologous pathogenic variant, HIV‐2UC2/9429, viral loads were similar in the HIV‐2‐immunized and control baboons. We conclude that although immunization using HIV‐2 expression libraries induces immune responses, this approach does not provide protection in baboons against intravenous challenge with HIV‐2.
Spontaneous rat bite fever in non‐human primates: a review of two cases
Authors: Valverde C.R. , Lowenstine L.J. , Young C.E. , Tarara R.P. , Roberts J.A.
Published: March 2003

Abstract: Rat bite fever is a worldwide zoonotic, non‐reportable disease. This entity encompasses similar, yet distinct, disease syndromes caused by Streptobacillus moniliformis or Spirillum minus. Naturally occurring rat bite fever has not been previously described in non‐human primates. This report describes two cases of non‐human primate rat bite fever caused by S. moniliformis; a rhesus macaque (Macaca mullata) with valvular endocarditis, and a titi monkey (Callicebus sp.) with septic arthritis. Potential sources of infection included direct contact, and ingestion of surface water or feed contaminated with rodent feces.
DNA prime/protein boost vaccine strategy in neonatal macaques against simian human immunodeficiency virus
Authors: Rasmussen Robert A. , Hofmann‐Lehmann R. , Montefiori D.C. , Li P.‐L. , Liska V. , Vlasak J. , Baba T.W. , Schmitz J.E. , Kuroda M.J. , Robinson H.L. , McClure H.M. , Lu S. , Hu S.‐L. , Rizvi T.A. , Ruprecht R.M.
Published: March 2003

Newborn macaques were vaccinated against a chimeric simian human immunodeficiency (SHIV) virus, SHIV‐vpu+, by DNA priming and boosting with homologous HIV‐1 gp160. Following SHIV‐vpu+ challenge, containment of infection was observed in 4 of 15 animals given DNA priming/protein boost vaccination and in three of four animals given gp160 boosts only. Rechallenge with homologous virus of six animals that contained the first challenge virus resulted in rapid viral clearance or low viral loads. Upon additional rechallenge with heterologous, pathogenic SHIV89.6P, four of these six animals maintained normal CD4+ T‐cell counts with no or limited SHIV89.6P infection. Our data suggest that humoral and cellular immune mechanisms may have contributed to the containment of SHIV89.6P; however, viral interference with SHIV‐vpu+ could also have played a role. Our results indicate that immunogenicity and efficacy of candidate AIDS vaccines are not affected when vaccination is initiated during infancy as compared with later in life.
Flow cytometric analysis of macaque whole blood for antigen‐specific intracellular cytokine production by T lymphocytes
Authors: Keeney Talitha S. , Nomura Laurel E. , Maecker Holder T. , Jagannadha Sastry K.
Published: March 2003

Abstract: We report here the standardized conditions for stimulation of macaque whole blood samples with various protein or peptide antigens, and production of significant intracellular levels of interferon gamma (IFN‐γ) and tumor necrosis factor alpha (TNF‐α) in CD4+ as well as CD8+ T lymphocytes. We observed significantly higher levels of TNF‐α compared with IFN‐γ in both CD4+ and CD8+ T lymphocytes from all the macaque whole blood samples stimulated with staphylococcal enterotoxin B (SEB) as an antigen. Similarly, when whole blood samples from rhesus macaques immunized with an HIV envelope peptide cocktail vaccine were stimulated with either the peptide cocktail or recombinant gp160, we observed production of significant levels of TNF‐α by both CD4+ and CD8+ T lymphocytes. These results strongly support the utility of the whole blood cytokine flow cytometry methodology for determining antigen‐specific immune responses of macaques in vaccine studies.
Scaling laws and instabilities in electric field‐enhanced smelting and refining of steel
Authors: Powell Adam , Dussault David
Published: March 2003

In electric field‐enhanced smelting of iron from slag, liquid iron formation at the cathode exhibits a Mullins–Sekerka instability, leading to the growth of fingers and enhancing the reaction rate. However, the liquid state of the growing iron phase leads to the expression of this instability that is qualitatively different from the classical example of growth of dendrites in solidification. As the molten iron fingers grow into the slag, there is a surface tension‐induced instability that leads to breakup into droplets, and this breakup is accelerated by the higher inward Lorentz force in the narrower regions due to higher current density. And if growth is directed downward, there is a buoyancy instability due to the higher density of iron than slag. These instabilities and their scaling behavior are treated analytically, and compared qualitatively with experimental measurements of finger size.
Influence of prey distribution on the functional response of lizards
Authors: Pitt William C. , Ritchie Mark E.
Published: March 2003

We experimentally examined the effect of invertebrate prey distribution on the functional response of a vertebrate predator. We predicted how predator consumption of prey would change with prey distribution using a scale‐dependent foraging model. This model predicted that prey consumption rate should decrease as a fixed density of resources becomes more dispersed in space as measured by its fractal dimension. The model incorporates an explicit description of the spatial distribution of prey into classical optimal foraging theory. We tested this prediction with foraging trials involving lizards feeding on grasshoppers in experimental arenas with a single grass species as vegetation cover. We manipulated grasshopper distribution associated with this grass by manipulating the distribution of vegetation in arenas to yield different fractal dimensions. Skinks foraging in arenas with a few large clumps of vegetation (low fractal dimension) captured significantly more prey at all prey densities than skinks foraging in arenas with many small clumps but not necessarily more evenly dispersed (high fractal dimension). These results support the predictions of the spatially dependent foraging model, and show that prey dispersion can strongly modify the predator functional response.
Habitat‐specific behavioural thermoregulation by black rat snakes (Elaphe obsoleta obsoleta)
Authors: Blouin‐Demers Gabriel , Weatherhead Patrick J.
Published: March 2003

Thermoregulation is thought to be the most important factor influencing habitat selection by terrestrial ectotherms, at least in temperate climates. The cost‐benefit model of thermoregulation predicts that ectotherms should invest more in thermoregulation when the costs of doing so are low (when the thermal quality of the habitat is high). However, the extent to which ectotherms vary their thermoregulatory behaviour according to the thermal quality of habitats is currently unknown. We studied the relationship between habitat use and thermoregulation in 53 black rat snakes using temperature‐sensitive radio‐transmitters. Among the habitats available to black rat snakes, edges had the highest thermal quality, retreat sites and forest were intermediate, and open habitats had the lowest thermal quality. Black rat snakes experienced more favourable body temperatures while in barns (retreat sites) than in edges, and in edges than in forest. During the day, the effectiveness and the extent of thermoregulation by the snakes were equal in barns and forest, but much lower in edges. In fact, black rat snakes selected thermally favourable microhabitats less than their availability while in edges. Therefore, more favourable body temperatures were not necessarily achieved in thermally superior habitats by increased thermoregulation, but simply because favourable temperatures were encountered more often in those habitats. This result is contrary to the central prediction of the cost‐benefit model of thermoregulation and we suggest that this model should be modified to put more emphasis on other costs of thermoregulation, such as increased predation risk or lost foraging opportunities.
Fractal species distributions do not produce power‐law species‐area relationships
Authors: Lennon Jack J. , Kunin William E. , Hartley Stephen
Published: March 2003

We derive the species‐area relationship (SAR) expected from an assemblage of fractally distributed species. If species have truly fractal spatial distributions with different fractal dimensions, we show that the expected SAR is not the classical power‐law function, as suggested recently in the literature. This analytically derived SAR has a distinctive shape that is not commonly observed in nature: upward‐accelerating richness with increasing area (when plotted on log‐log axes). This suggests that, in reality, most species depart from true fractal spatial structure. We demonstrate the fitting of a fractal SAR using two plant assemblages (Alaskan trees and British grasses). We show that in both cases, when modelled as fractal patterns, the modelled SAR departs from the observed SAR in the same way, in accord with the theory developed here. The challenge is to identify how species depart from fractality, either individually or within assemblages, and more importantly to suggest reasons why species distributions are not self‐similar and what, if anything, this can tell us about the spatial processes involved in their generation.
Plethodontid salamanders do not conform to “general rules” for ectotherm life histories: insights from allocation models about why simple models do not make accurate predictions
Authors: Bernardo J. , Reagan‐Wallin N. L.
Published: March 2003

Recent theoretical models hold that temperature imposes unalterable physiological effects on ectotherm growth and development such that their life histories are dictated by local biophysical environments. Models relying on this premise have been offered to explain many life history phenotypes including threshold traits such as age/size at metamorphosis/maturity. Because threshold traits are thought to influence adult fitness components by affecting performance of an individual in its new habitat, they are evolutionarily important components of complex life cycles. Consequently, the ecological and genetical basis of variation in such traits has been the focus of a large research program by evolutionary biologists, and amphibians have been model systems for these studies in the last three decades. Smith‐Gill and Berven proposed a physiological model to explain commonly observed clinal patterns of variation in metamorphosis, and it appears to account successfully for patterns observed in a few species of pond‐breeding frogs and salamanders (RanaandAmbystoma). However, six species of stream‐breeding salamanders (family Plethodontidae:Desmognathus, Pseudotriton, Eurycea) contradict both the phenotypic patterns found in nature for pond‐breeding species as well as the predictions of this model. Four of the six species of plethodontids have significantly larger metamorphs at lower, warmer elevations (or more southerly latitudes) rather than at higher, cooler sites; two species show no clinal pattern. In light of these results, we critically examine the assumptions of and support for SGB. We propose alternative hypotheses to explain patterns of variation in metamorphic traits along thermal gradients, focusing on a) differences between pond‐breeding Amphibia and plethodontids in basic biology and larval habitats, b) gradients in other biotic and abiotic factors, and c) other effects of temperature on organismal function. Finally, we discuss our results in the context of current models of how ectotherm life histories are affected by temperature.
Effects of nutrients and predators on an old‐field food chain: interactions of top‐down and bottom‐up processes
Authors: Moran Matthew D. , Scheidler Alison R.
Published: March 2003

How top‐down and bottom‐up processes interact in terrestrial systems is an important ecological question, yet well designed studies addressing this question are rare. We tested the interaction of these two processes in an old‐field community by simultaneously manipulating nutrient level and large cursorial spider density in a replicated field experiment. Spider density and nutrient level interacted to determine overall growth of plants, with the greatest plant biomass occurring in plots with normal predator density and elevated nutrients. Plant growth was increased for a short period of time in all plots with elevated nutrient levels. However, with predator abundance reduced, Homoptera were able to increase in nutrient addition plots and cause a subsequent reduction in plant growth. Other herbivorous arthropods appeared unaffected by our experimental treatments. Spider reduction also significantly reduced plant diversity while nutrient effects on plant diversity were nonsignificant. Manipulation of predators and nutrients affected the biomass and behavior of smaller cursorial spiders. Biomass of these smaller predators increased with top spider reduction, which in turn enhanced emigration of these smaller spiders. This study demonstrates that top‐down and bottom‐up processes can interact to affect the biomass of several different trophic levels and the behavior of organisms within those trophic levels. However, only some components of this diverse community were significantly affected by our manipulations, indicating that strong trophic interactions can exist within a framework of weaker interactions in a diverse system. Researchers of trophic interactions need to recognize that top‐down and bottom‐up processes are not acting in isolation. Therefore, results of studies investigating top‐down or bottom‐up processes alone must be interpreted cautiously, and ideally these processes should not be studied independently.
Developmental plasticity in birch leaves: defoliation causes a shift from glandular to nonglandular trichomes
Authors: Rautio Pasi , Markkola Annamari , Martel Jocelyn , Tuomi Juha , Härmä Esa , Kuikka Karita , Siitonen Annika , Riesco Iola Leal , Roitto Marja
Published: March 2003

The structures on leaf surfaces, e.g. trichomes, can act as effective antiherbivory mechanisms as chemical repellents. Structural defences usually represent constitutive resistance, but there are also a few cases of inducible morphological defences. We tested whether defoliation may induce changes in trichome production in white birch (Betula pubescens). The studied birches were either 0, 50 or 100% defoliated during the previous or current summer, and we measured the alterations in the production of glandular vs. nonglandular leaf trichomes, developmental instability (fluctuating asymmetry, FA) and leaf and shoot growth. We detected a clear shift from glandular to nonglandular leaf trichomes following previous‐year defoliation but not after current‐year defoliation. Furthermore, the density of nonglandular trichomes around the mid‐vein of leaves increased following previous‐year defoliation but decreased after current‐year defoliation. While leaf and shoot growth showed a distinct decrease in response to defoliation, FA turned out to be less sensitive. Consequently, previous‐year defoliation can induce the production of nonglandular trichomes in birch leaves. Because this response was accompanied by a reduction in glandular trichomes, the present results may suggest a trade‐off between the different trichome types of birch leaves.
Forest habitat characteristics affect balance between sexual reproduction and clonal propagation of the ectomycorrhizal mushroom Hebeloma cylindrosporum
Authors: Guidot Alice , Gryta Hervé , Gourbière François , Debaud Jean‐Claude , Marmeisse Roland
Published: March 2003

We investigated how habitat characteristics and in particular the level of disturbance was affecting colonisation processes and population dynamics of an ectomycorrhizal fungus. The basidiomycete Hebeloma cylindrosporum associated with Pinus pinaster trees occurs in two distinct habitats within the forest dune ecosystem along the Atlantic coast of France. The ‘dune habitat’ (D habitat) is characterised by scattered trees growing in almost pure sand at the extreme fringe of the forest marking the transition with the bare dune. The ‘forest habitat’ (F habitat) is within the mature forest in places of high human frequentation which prevents litter and humus accumulation. We studied over several years (up to ten) populations of H. cylindrosporum present in three geographic sites. Within each site we studied two areas corresponding each to one of the two possible habitats. In all sampled areas fruit bodies occurred within discrete patches of ground. Although an interaction between habitat and geographic site existed, habitat had significant effects on patch sizes and patch internal densities. Compared to the F habitat, patches in the D habitat were significantly larger and presented a lower density of fruit bodies. Patches very seldom occurred at the same place from one year to the next in the F habitat when in most cases they were perennial and increased in size in the D habitat. Fruit body size, which reflects reproductive output of the genets, differed between the two habitats (means of the cap diameters of 25.6 and 40.4 mm in respectively the F and D habitats). Almost all patches in the F habitat were made of several annual genets each producing on average 1.6 fruit bodies while most patches in the D habitat were dominated by one perennial genet which could simultaneously produce up to 60 fruit bodies. Under‐representation of small sized genets in the D habitat suggests a low level of sexual recruitment in this habitat despite the large number of fruit bodies (and therefore of spores) produced by each of the existing genets. We therefore suggest that H. cylindrosporum could be considered as a fugitive species. Genets of this species survive in the D habitat in which few ectomycorrhizal fungal competitors occur. This habitat could represent the optimal habitat for this species. In the F habitat frequent recruitment could occur in ‘empty patches’ resulting from the local and transient elimination of competitors induced by human disturbance.
Seed addition experiments are more likely to increase recruitment in larger‐seeded species
Authors: Moles Angela T. , Westoby Mark
Published: March 2003

Colonisation theory predicts that large‐seeded species are more likely to show increased seedling recruitment in response to seed addition than are small‐seeded species. This is both because their seedlings tend to have better survivorship potential, and because their background density of germinating seedlings tends to be lower. We tested this hypothesis by combining data from a recent review of seed addition studies with seed mass data. Logistic regressions showed positive relationships between seed mass and propensity to increase seedling establishment in response to seed addition in experiments in which establishment success was assessed within 6 months or a year, but not in experiments in which establishment success was assessed more than a year after seed addition. When data for all time periods were combined, a generalised linear model including terms for seed mass, time and an interaction term showed a significant positive relationship between seed mass and species response to seed addition. Thus, knowing a species' seed mass significantly increased our ability to predict its response to seed supplementation.
Dysregulated expression of bcl‐2 and bax in oral carcinomas: evidence of post‐transcriptional control
Authors: Chen Yu , Kayano Teruo , Takagi Minoru
Published: March 2003

Abstract: A study was conducted to investigate the gene expression of bcl‐2 and bax in oral squamous cell carcinomas. We used reverse–transcriptase‐polymerase chain reacion (RT–PCR) to evaluate the expression of bcl‐2 and bax mRNAs and the ratio of bcl‐2/bax mRNA, and employed immunohistochemistry to investigate the bcl‐2‐ and bax‐encoded proteins. It was observed that the expression level of bcl‐2 mRNA or bax mRNA was not consistent with their protein level in some cases. Higher expression of bcl‐2 mRNA and stronger immunostaining of bcl‐2 protein were found in oral squamous cell carcinomas than in the adjacent histologically normal oral epithelium. These findings were more prominent in poorly differentiated carcinomas. No significant differences in bax mRNA and protein were observed between carcinomas and the adjacent histologically normal oral epithelium. However, poorly differentiated carcinomas showed very weak immunostaining for bax. The ratio of bcl‐2/bax mRNA was higher in carcinomas than in the adjacent histologically normal oral epithelium, and higher ratios were seen in most of poorly differentiated carcinomas. This study supplies indirect evidence of post‐transcriptional control of bcl‐2 and bax expression, and suggests that dysregulated expression of bcl‐2 and bax may be related to the differentiation of oral squamous cell carcinomas.
Oral findings in three different groups of immunocompromised patients
Authors: Meyer Ulrich , Kleinheinz Johannes , Handschel Jörg , Kruse‐Lösler Birgit , Weingart Dieter , Joos Ulrich
Published: March 2003

Abstract: The objective of this study was to determine the frequency of oral, dental and periodontal findings in three different groups of immunocompromised patients and in a healthy control group, to evaluate whether there is a correlation between manifestations of disease and immunologic parameters. The survey included 46 patients with a diagnosis of systemic lupus erythematosus, 48 heart transplant recipients, and 53 adult patients suffering from acute leukemias. Fifty matched healthy subjects were used as a control group. Each patient had to answer questions on medical and dental health and underwent a thorough oral, dental and serological investigation. Oral mucosal lesions were found in nearly half of all immunocompromised patients (49.6%), but in only 26% of control patients. No significant associations were found between different types of oral lesions and the underlying cause of immunosuppression. Leukemia patients showed age‐unrelated higher scores in periodontal indices (P<0.05). Laboratory parameters failed to be significant in the assessment of oral health.
Endogenous TGF‐β1 inhibits the growth and metastatic dissemination of rat oral carcinoma cell lines but enhances local bone resorption
Authors: Davies Maria , Prime Stephen S. , Stone Andrea M. , Huntley Suzy P. , Eveson John W. , Paterson Ian C.
Published: March 2003

Abstract: This study examined the effect of stable transfection of latent transforming growth factor‐β1 (TGF‐β1) cDNA into a predominantly polygonal, 4 nitroquinoline N‐oxide (4NQO)‐induced rat oral keratinocyte cell line. Seven polygonal and five spindle clonal populations were isolated that overexpressed TGF‐β1 protein by approximately two‐ to four‐fold compared to vector‐only transfected controls. Neutralisation experiments indicated that the majority of protein was in the latent form. There was no change in the proportion of polygonal and spindle cells in vitro after transfection with TGF‐β1 cDNA. Polygonal and spindle cells that overexpressed TGF‐β1 produced similar amounts of protein and grew more slowly in vitro than controls. The parent cell line and all transfected cells were growth inhibited (60–75%) by exogenous TGF‐β1. Orthotopic transplantation of the parent and the vector‐only control cell lines resulted in primary tumours in the floor of the mouth in almost 100% (20/21) of athymic mice, with no evidence of bone resorption at the site of the primary tumour and pulmonary metastatic tumour deposits in some 40% (7/20) of these animals. The polygonal and spindle cells that overexpressed TGF‐β1 behaved similarly following orthotopic transplantation. A 96% (23/24) primary tumour take was evident following transplantation of cells that overexpressed TGF‐β1, with a significantly (P<0.02) higher number of animals showing bone resorption at the site of the primary tumour (35%; 8/23) compared to controls. By contrast, there was a significant (P<0.03) decrease in the number of animals with pulmonary metastases (4%; 1/23) following transplantation of TGF‐β1 overexpressing cells compared to controls. Overexpression of TGF‐β1 did not alter tumour cell differentiation in vivo. The results demonstrate that endogenous TGF‐β1 functions as a tumour suppressor in the rat‐4NQO model of oral carcinogenesis without altering tumour cell morphology or differentiation but can also act to promote local bone resorption.
Sialochemical markers of salivary gland involvement with Sjögren’s syndrome secondary to rheumatoid arthritis and primary biliary cirrhosis
Authors: Carpenter Guy H. , Proctor Gordon B. , Pankhurst Caroline L. , O'Donohue John , Scott David , Hunnable Mark P.
Published: March 2003

Abstract: Sjögren’s syndrome is an autoimmune condition affecting the lacrimal and salivary glands and can be associated with rheumatoid arthritis and primary biliary cirrhosis. Parotid salivas collected from patients and normal controls were analysed for lactoferrin, IgA and beta2‐microglobulin (measured by ELISA), and cystatin (measured by a enzyme inhibition assay). Output data provided less variable means, whilst expressing results as a proportion of the total protein provided greater specificity as markers for Sjögren’s syndrome. Levels of specificity for IgA, lactoferrin and beta2‐microglobulin were all high (100, 95 and 100%, respectively). Sensitivity levels of these markers (but not cystatin) tended to be similar for Sjögren’s syndrome secondary to primary biliary cirrhosis (IgA, 25%; lactoferrin, 63%; and beta2‐microglobulin, 50%), compared to Sjögren’s syndrome secondary to connective tissue diseases such as rheumatoid arthritis (IgA, 50%; lactoferrin, 86%; and beta2‐microglobulin; 38%).
Copper stimulates human oral fibroblasts in vitro: a role in the pathogenesis of oral submucous fibrosis
Authors: Trivedy C. , Meghji S. , Warnakulasuriya K. A. A. S. , Johnson N. W. , Harris M.
Published: March 2003

Abstract: Copper is implicated in the pathogenesis of several fibrotic disorders. Areca nut has been shown to have a high copper content and areca chewing is associated with oral submucous fibrosis (OSF). The effects of copper on human oral fibroblasts were investigated in vitro. Human oral fibroblasts were incubated with copper chloride (CuCl2) at concentrations ranging from 0.01 μM to 500 μM for 24 h, and in vitro cell proliferation was assayed by incorporation of tritiated–thymidine; soluble and non‐soluble collagen synthesis was assayed using tritiated‐proline. Addition of copper chloride at concentrations ranging from 0.1 μM to 50 μM increased the collagen synthesis by the oral fibroblasts compared with growth without copper (P<0.05). The addition of copper chloride neither increased the synthesis of non‐collagenous proteins by the fibroblasts nor influenced their proliferation rate. We conclude that copper upregulates collagen production in oral fibroblasts. This appears to be concentration dependent, with peak collagen synthesis at 50 μM CuCl2. These in vitro results taken together with the recent findings of copper in oral biopsies from OSF subjects support the hypothesis that copper in areca nut acts as a mediator of OSF.
Catenin dislocation in oral pemphigus vulgaris
Authors: Mignogna Michele Davide , Pannone Giuseppe , Lo Muzio Lorenzo , Staibano Stefania , Bucci Eduardo
Published: March 2003

Abstract: Cell‐to‐cell adhesion is mediated by cadherins (integral membrane proteins), which form a complex with catenins (cytoplasmatic proteins). While E‐cadherin expression has been extensively studied in many human skin diseases, less is known about the expression levels of catenins in oral blistering diseases. The purpose of this study was to evaluate the role of these proteins in the pathogenesis of acantholysis in oral pemphigus vulgaris. We evaluated by immunohistochemistry beta‐ and gamma‐catenin expression in 7 cases of oral pemphigus vulgaris (PV) at various stages of the disease and, as controls, in 18 healthy patients. Healthy cases showed, as reported in the literature, a strong reactivity with both beta‐ and gamma‐catenins, with the intensity of staining progressively decreasing from the spinous to the keratinised layers of epithelium, which had a prevalent cellular membrane expression. In PV patients, we detected a loss of membrane expression of these molecules with a progressive displacement of the signal toward the cytosol and, for gamma‐catenin, nuclear dislocation, particularly in areas with intense acantholysis.
Influence of aging on candidal growth and adhesion regulatory agents in saliva
Authors: Tanida Toyohiro , Ueta Eisaku , Tobiume Aya , Hamada Toshihiro , Rao Fu , Osaki Tokio
Published: March 2003

Abstract: Although oral candidiasis is frequently seen in the elderly, the factors determining candidal growth have insufficiently been explored. Hence, we examined the influence of aging on candidal adhesion and growth‐inhibitory agents in saliva in 45 healthy volunteers and 60 patients with oral candidiasis. Both non‐stimulated and stimulated salivary flow rates (SFRs) in the healthy controls decreased with aging. A gradual decrease of SFRs with aging was also observed in the patients, and the SFR levels were markedly lower than those in the controls. Although the salivary glucose levels were almost constant in all age groups, secretory immunoglobulin A and lactoferrin levels in saliva were significantly decreased statistically with age, and a marginal age‐associated decrease in transferrin levels was also observed. In addition, the generation of superoxide from neutrophils in saliva and their Candida killing activity decreased with age, and these phenomena were more apparent in the patients. Furthermore, a larger number of Candida adhered to oral keratinocytes obtained from the elderly healthy controls than to those obtained from young controls. Correspondingly, keratinocytes from the aged controls showed more concanavalin‐A binding sites than those from the young controls. However, oral Candida did not increase with increasing age in the controls, although an age‐associated increase of oral Candida was observed in the patients. Taken together, these results indicate that the decreases of SFRs and salivary anti‐candidal factors, suppression of salivary neutrophil function and the increase of candidal adhesion sites on keratinocytes predispose elderly individuals to oral candidiasis.
Discrimination of ameloblastomas from odontogenic keratocysts by cytokine levels and gelatinase species of the intracystic fluids
Authors: Kubota Yasutaka , Nitta Shuichi , Oka Shoji , Nakagawa Subemitsu , Ninomiya Tomohiro , Shirasuna Kanemitsu
Published: March 2003

Abstract: In the present study, we measured the levels of the cytokines and gelatinase species in the fluids of ameloblastomas and odontogenic keratocysts, and showed that ameloblastomas can be distinguished from odontogenic keratocysts by the use of these biochemical data. We found that interleukin (IL)‐1α and IL‐1β levels in the intracystic fluids of ameloblastomas were significantly lower than those in the fluids of odontogenic keratocysts, while IL‐6 levels in the fluids of ameloblastomas were significantly higher than those in the fluids of odontogenic keratocysts. On the other hand, no significant differences in tumor necrosis factor (TNF)‐α levels of the fluids were detected between ameloblastomas and odontogenic keratocysts. An immunohistochemical study revealed that the staining intensity of IL‐1α, IL‐1β and TNF‐α in the tumor cells of ameloblastomas was significantly weaker than that in the epithelial cells of odontogenic keratocysts, while the staining intensity of IL‐6 in the tumor cells was significantly stronger than that in the epithelial cells of odontogenic keratocysts. Gelatin zymography of the fluids showed that only a small amount of pro‐MMP‐9 was detected in ameloblastomas, while both pro‐MMP‐9 and the active form of MMP‐9 were detected in 8 of 10 cases of odontogenic keratocysts. Thus, ameloblastomas can be distinguished from odontogenic keratocysts by measuring IL‐1α and IL‐6 levels, and gelatinase species in the fluids.
Autofluorescence spectroscopy for in vivo diagnosis of DMBA‐induced hamster buccal pouch pre‐cancers and cancers
Authors: Wang Chih‐Yu , Tsai Tsuimin , Chen Hui‐Chun , Chang Shu‐Chen , Chen Chin‐Tin , Chiang Chun‐Pin
Published: March 2003

Background:  Our previous ex vivo study has shown that autofluorescence spectroscopy at 330‐nm excitation can discriminate specimens of normal buccal pouch mucosa (normal), epithelial hyperkeratosis (hyperkeratosis), epithelial dysplasia (dysplasia), and squamous cell carcinoma (SCC) taken from DMBA‐treated hamsters by using the method of partial least‐squares discriminant analysis (PLSDA).

Methods:  This study used a fiber optics‐based fluorescence spectroscopy system to measure the autofluorescence spectra of 23 normal, 14 hyperkeratosis, 28 dysplasia, and 10 SCC samples in vivo. PLSDA with cross‐validation was used to analyze the autofluorescence spectral data of all samples.

Results:  We found that at 330‐nm excitation, the autofluorescence spectra of all samples had two main peaks: one at 380 nm and the other at 460 nm. The hyperkeratosis samples had a higher 380‐nm emission peak (EP) and a lower 460‐nm EP than normal samples. On the contrary, the dysplasia samples had a lower 380‐nm EP and a higher 460‐nm EP than normal samples. Furthermore, the SCC samples had a much lower 380‐nm EP and a much higher 460‐nm EP than all other samples. To quantify the spectral changes during the progression of oral carcinogenesis, ratios of the area under the spectrum of 380 ± 15 nm to that under the spectrum of 460 ± 15 nm (denoted as A380 ± 15 nm/A460 ± 15 nm) for all samples were calculated. The mean ratio values of A380 ± 15 nm/A460 ± 15 nm decreased gradually from hyperkeratosis to normal, to dysplasia, and to SCC samples. Significant differences in this mean ratio were found between any two groups of normal, hyperkeratosis, dysplasia, and SCC samples. By choosing proper thresholds, PLSDA with cross‐validation could provide an accurate identification rate of 86% for hyperkeratosis, of 87% for normal, and of 89% for dysplasia samples. In addition, by choosing a proper threshold, we could separate benign (normal and hyperkeratosis) from dysplasia or SCC tissues with a sensitivity of 92% and a specificity of 95%.

Conclusion:  Our results indicate that the autofluorescence spectroscopy technique is a useful diagnostic tool for in vivo diagnosis of oral pre‐cancers and cancers in DMBA‐induced hamster buccal pouch carcinogenesis model.