bluuebunny/crossref_metadata_2025 huggingface dataset:
Nanofibres and their Influence on Cells for Tissue Regeneration
Authors: Wang Yanping Karen , Yong Thomas , Ramakrishna Seeram
Published: November 2005

Synthetic polymer and biopolymer nanofibres can be fabricated through self-assembly, phase separation, electrospinning, and mechanical methods. These novel functional biocompatible polymers are very promising for a variety of future biomedical applications. There are many characteristics of nanofibres that would potentially influence cell growth and proliferation. As such, many studies have been carried out to elucidate the cell–nanofibre interaction with the purpose of optimizing the matrix for cell growth and tissue regeneration. In this Review, we present current literatures and our research on the interactions between cells and nanofibres, and the potentials of nanofibre scaffolds for biomedical applications.
Temporally resolved interactions between antigen-stimulated IgE receptors and Lyn kinase on living cells
Authors: Larson Daniel R. , Gosse Julie A. , Holowka David A. , Baird Barbara A. , Webb Watt W.
Published: November 2005

Upon cross-linking by antigen, the high affinity receptor for immunoglobulin E (IgE), FcεRI, is phosphorylated by the Src family tyrosine kinase Lyn to initiate mast cell signaling, leading to degranulation. Using fluorescence correlation spectroscopy (FCS), we observe stimulation-dependent associations between fluorescently labeled IgE-FcεRI and Lyn-EGFP on individual cells. We also simultaneously measure temporal variations in the lateral diffusion of these proteins. Antigen-stimulated interactions between these proteins detected subsequent to the initiation of receptor phosphorylation exhibit time-dependent changes, suggesting multiple associations between FcεRI and Lyn-EGFP. During this period, we also observe a persistent decrease in Lyn-EGFP lateral diffusion that is dependent on Src family kinase activity. These stimulated interactions are not observed between FcεRI and a chimeric EGFP that contains only the membrane-targeting sequence from Lyn. Our results reveal real-time interactions between Lyn and cross-linked FcεRI implicated in downstream signaling events. They demonstrate the capacity of FCS cross-correlation analysis to investigate the mechanism of signaling-dependent protein–protein interactions in intact, living cells.
CaMKII tethers to L-type Ca2+ channels, establishing a local and dedicated integrator of Ca2+ signals for facilitation
Authors: Hudmon Andy , Schulman Howard , Kim James , Maltez Janet M. , Tsien Richard W. , Pitt Geoffrey S.
Published: November 2005

Ca2+-dependent facilitation (CDF) of voltage-gated calcium current is a powerful mechanism for up-regulation of Ca2+ influx during repeated membrane depolarization. CDF of L-type Ca2+ channels (Cav1.2) contributes to the positive force–frequency effect in the heart and is believed to involve the activation of Ca2+/calmodulin-dependent kinase II (CaMKII). How CaMKII is activated and what its substrates are have not yet been determined. We show that the pore-forming subunit α1C (Cavα1.2) is a CaMKII substrate and that CaMKII interaction with the COOH terminus of α1C is essential for CDF of L-type channels. Ca2+ influx triggers distinct features of CaMKII targeting and activity. After Ca2+-induced targeting to α1C, CaMKII becomes tightly tethered to the channel, even after calcium returns to normal levels. In contrast, activity of the tethered CaMKII remains fully Ca2+/CaM dependent, explaining its ability to operate as a calcium spike frequency detector. These findings clarify the molecular basis of CDF and demonstrate a novel enzymatic mechanism by which ion channel gating can be modulated by activity.
Centrobin
Authors: Zou Chaozhong , Li Jun , Bai Yujie , Gunning William T. , Wazer David E. , Band Vimla , Gao Qingshen
Published: November 2005

In mammalian cells, the centrosome consists of a pair of centrioles and amorphous pericentriolar material. The pair of centrioles, which are the core components of the centrosome, duplicate once per cell cycle. Centrosomes play a pivotal role in orchestrating the formation of the bipolar spindle during mitosis. Recent studies have linked centrosomal activity on centrioles or centriole-associated structures to cytokinesis and cell cycle progression through G1 into the S phase. In this study, we have identified centrobin as a centriole-associated protein that asymmetrically localizes to the daughter centriole. The silencing of centrobin expression by small interfering RNA inhibited centriole duplication and resulted in centrosomes with one or no centriole, demonstrating that centrobin is required for centriole duplication. Furthermore, inhibition of centriole duplication by centrobin depletion led to impaired cytokinesis.
A primate virus generates transformed human cells by fusion
Authors: Duelli Dominik M. , Hearn Stephen , Myers Michael P. , Lazebnik Yuri
Published: November 2005

Amodel that explains both the origin and sporadic nature of cancer argues that cancer cells are a chance result of events that cause genomic and epigenetic variability. The prevailing view is that these events are mutations that affect chromosome segregation or stability. However, genomic and epigenetic variability is also triggered by cell fusion, which is often caused by viruses. Yet, cells fused by viruses are considered harmless because they die. We provide evidence that a primate virus uses both viral and exosomal proteins involved in cell fusion to produce transformed proliferating human cells. Although normal cells indeed fail to proliferate after fusion, expression of an oncogene or a mutated tumor suppressor p53 in just one of the fusion partners is sufficient to produce heterogeneous progeny. We also show that this virus can produce viable oncogenically transformed cells by fusing cells that are otherwise destined to die. Therefore, we argue that viruses can contribute to carcinogenesis by fusing cells.
Spying on IgE receptor signaling
Authors: Toomre Derek
Published: November 2005

Plasma membrane organization and the potential role, or not, of lipid raft microdomains in signal transduction is a controversial topic. Cross-correlation fluorescent correlation spectroscopy (CC-FCS) shows promise as a new approach to rapidly probe protein–protein interactions in living cells during signal transduction. CC-FCS data from studies of IgE receptor signaling challenge models of large stable lipid raft signaling domains and reveal a new complexity in the dynamic (re)organization of signaling complexes.
Suppression of allergic airway inflammation by helminth-induced regulatory T cells
Authors: Wilson Mark S. , Taylor Matthew D. , Balic Adam , Finney Constance A.M. , Lamb Jonathan R. , Maizels Rick M.
Published: November 2005

Allergic diseases mediated by T helper type (Th) 2 cell immune responses are rising dramatically in most developed countries. Exaggerated Th2 cell reactivity could result, for example, from diminished exposure to Th1 cell–inducing microbial infections. Epidemiological studies, however, indicate that Th2 cell–stimulating helminth parasites may also counteract allergies, possibly by generating regulatory T cells which suppress both Th1 and Th2 arms of immunity. We therefore tested the ability of the Th2 cell–inducing gastrointestinal nematode Heligmosomoides polygyrus to influence experimentally induced airway allergy to ovalbumin and the house dust mite allergen Der p 1. Inflammatory cell infiltrates in the lung were suppressed in infected mice compared with uninfected controls. Suppression was reversed in mice treated with antibodies to CD25. Most notably, suppression was transferable with mesenteric lymph node cells (MLNC) from infected animals to uninfected sensitized mice, demonstrating that the effector phase was targeted. MLNC from infected animals contained elevated numbers of CD4+CD25+Foxp3+ T cells, higher TGF-β expression, and produced strong interleukin (IL)-10 responses to parasite antigen. However, MLNC from IL-10–deficient animals transferred suppression to sensitized hosts, indicating that IL-10 is not the primary modulator of the allergic response. Suppression was associated with CD4+ T cells from MLNC, with the CD4+CD25+ marker defining the most active population. These data support the contention that helminth infections elicit a regulatory T cell population able to down-regulate allergen induced lung pathology in vivo.
CD4 T cells integrate signals delivered during successive DC encounters in vivo
Authors: Celli Susanna , Garcia Zacarias , Bousso Philippe
Published: November 2005

The cellular mode of T cell priming in vivo remains to be characterized fully. We investigated the fate of T cell–dendritic cell (DC) interactions in the late phase of T cell activation in the lymph node. In general, CD4 T cells detach from DCs before undergoing cell division. Using a new approach to track the history of antigen (Ag)-recognition events, we demonstrated that activated/divided T cells reengage different DCs in an Ag-specific manner. Two-photon imaging of intact lymph nodes suggested that T cells could establish prolonged interactions with DCs at multiple stages during the activation process. Importantly, signals that are delivered during subsequent DC contacts are integrated by the T cell and promote sustained IL-2Rα expression and IFN-γ production. Thus, repeated encounters with Ag-bearing DCs can occur in vivo and modulate CD4 T cell differentiation programs.
Interaction of CagA with Crk plays an important role in Helicobacter pylori–induced loss of gastric epithelial cell adhesion
Authors: Suzuki Masato , Mimuro Hitomi , Suzuki Toshihiko , Park Morag , Yamamoto Tadashi , Sasakawa Chihiro
Published: November 2005

CagA protein is a major virulence factor of Helicobacter pylori, which is delivered into gastric epithelial cells and elicits growth factor–like responses. Once within the cells, CagA is tyrosine phosphorylated by Src family kinases and targets host proteins required to induce the cell responses. We show that the phosphorylated CagA binds Crk adaptor proteins (Crk-II, Crk-I, and Crk-L) and that the interaction is important for the CagA-mediated host responses during H. pylori infection. H. pylori–induced scattering of gastric epithelial cells in culture was blocked by overexpression of dominant-negative Crk and by RNA interference–mediated knockdown of endogenous Crk. H. pylori infection of the gastric epithelium induced disruption of E-cadherin/catenin–containing adherens junctions, which was also dependent on CagA/Crk signaling. Furthermore, inhibition of the SoS1/H-Ras/Raf1, C3G/Rap1/B-Raf, or Dock180/Rac1/Wiskott-Aldrich syndrome protein family verprolin homologous protein pathway, all of which are involved downstream of Crk adaptors, greatly diminished the CagA-associated host responses. Thus, CagA targeting of Crk plays a central role in inducing the pleiotropic cell responses to H. pylori infection that cause several gastric diseases, including gastric cancer.
IL-2 production in developing Th1 cells is regulated by heterodimerization of RelA and T-bet and requires T-bet serine residue 508
Authors: Hwang Eun Sook , Hong Jeong-Ho , Glimcher Laurie H.
Published: November 2005

Interleukin (IL)-2 is the predominant cytokine that is produced by naive Th cells in a primary response. It is required for proliferation and differentiation of Th precursor cells into effector cells. Initial high-level IL-2 production is followed by its decline, and the concomitant induction of cytokines that are typical of the differentiated state. Although the factors that are responsible for the early induction of IL-2 are well defined, the mechanisms that are responsible for its down-regulation in later stages of Th development have not been studied as much. Previous work from our laboratory revealed a repressor function for the T-box transcription factor, T-bet, in IL-2 gene transcription. Here, we report that T-betS508 is required for the optimal repression of IL-2 production in developing Th1 cells. Phosphorylation of T-betS508 by casein kinase I and glycogen synthase kinase-3 kinases accompanies T-bet's interaction with the RelA nuclear factor–κB transcription factor. Heterodimerization of T-bet and RelA interferes with the binding of RelA to the IL-2 promoter, and hence, transcriptional activation of the IL-2 gene by RelA.
Autoamplification of NFATc1 expression determines its essential role in bone homeostasis
Authors: Asagiri Masataka , Sato Kojiro , Usami Takako , Ochi Sae , Nishina Hiroshi , Yoshida Hiroki , Morita Ikuo , Wagner Erwin F. , Mak Tak W. , Serfling Edgar , Takayanagi Hiroshi
Published: November 2005

NFATc1 and NFATc2 are functionally redundant in the immune system, but it was suggested that NFATc1 is required exclusively for differentiation of osteoclasts in the skeletal system. Here we provide genetic evidence that NFATc1 is essential for osteoclast differentiation in vivo by adoptive transfer of NFATc1−/− hematopoietic stem cells to osteoclast-deficient Fos−/− mice, and by Fos−/− blastocyst complementation, thus avoiding the embryonic lethality of NFATc1−/− mice. However, in vitro osteoclastogenesis in NFATc1-deficient cells was rescued by ectopic expression of NFATc2. The discrepancy between the in vivo essential role of NFATc1 and the in vitro effect of NFATc2 was attributed to selective autoregulation of the NFATc1 gene by NFAT through its promoter region. This suggested that an epigenetic mechanism contributes to the essential function of NFATc1 in cell lineage commitment. Thus, this study establishes that NFATc1 represents a potential therapeutic target for bone disease and reveals a mechanism that underlies the essential role of NFATc1 in bone homeostasis.
Lost in translation
Authors: von Herrath Matthias G. , Nepom Gerald T.
Published: November 2005

Induction of selective, autoantigen-specific tolerance is the “holy grail” for the treatment and prevention of autoimmune diseases. Despite successes in many differential murine models, rational and efficient translation to the clinic has been difficult. During the 5th Annual Federation of Clinical Immunological Societies (FOCIS) Meeting, May 12–16, 2005, in Boston, MA, a Kirin-sponsored “Ideashop” was convened to discuss this theme amongst scientists, clinicians, industry partners, and funding agencies.
Military influence upon the development of anaesthesia from the American Civil War (1861–1865) to the outbreak of the First World War
Authors: Metcalfe N. H.
Published: November 2005

The American Civil War (1861–1865) helped cement the place of anaesthesia in American medical practice and offered new insights into the speciality. The advantages that ensued were to offer long‐term security to anaesthesia but the short‐term gains were negligible. The Franco‐Prussian War (1870–1871) exerted a negative influence upon nitrous oxide and oxygen research through the loss of leading civilian scientists to military duty. Later, the Boer Wars (1899–1902) helped stabilise the popularity of chloroform after the Hyderabad Commissions but were of little experimental value to anaesthesia. In the early 20th Century, the military continued to be operational without either specialist anaesthetists or an interest in developing military anaesthesia. However, the lack of anaesthetic development was largely due to problems with economics and academic infrastructure rather than to simple military neglect.
Repeated‐dose effects of mequitazine, cetirizine and dexchlorpheniramine on driving and psychomotor performance
Authors: Theunissen Eef L. , Vermeeren Annemiek , Ramaekers Johannes G.
Published: November 2005

Aims

Previous studies have demonstrated that the antihistamines mequitazine, cetirizine and dexchlorpheniramine produce mild sedation after single doses. It is unknown, however, whether acute sedation persists after repeated dosing. Therefore, this study assessed the effects of repeated dosing of these antihistamines on driving and psychomotor performance.

Methods

Sixteen healthy volunteers were treated with mequitazine 10 mg q.a.m., cetirizine 10 mg q.a.m., dexchlorpheniramine Repetab 6 mg b.i.d. and placebo for four separate 8‐day periods. Drug effects were assessed on days 1 and 8 using on‐the‐road driving tests (highway driving and car following), psychomotor tests (tracking and divided attention) and subjective questionnaires.

Results

Dexchlorpheniramine and mequitazine significantly impaired driving performance on the highway driving test on the first day; dexchlorpheniramine increased Standard Deviation of Lateral Position by 2 cm [95% confidence interval (CI) 0.5, 3.8] and mequitazine by 2.5 cm (CI 1.0, 4.3). These effects on driving performance disappeared after 8 days of treatment. No effect of treatment was found on car following, tracking and divided attention. Although subjective ratings confirmed that subjects knew their driving had been impaired in the mequitazine and dexchlorpheniramine condition after completion of the highway driving test on day 1, they did not expect their driving to be affected before the start of the test. Cetirizine did not impair performance on any of the tests.

Conclusions

Single doses of mequitazine 10 mg and dexchlorpheniramine Repetab 6 mg cause mild driving impairment. However, when taken over several days, the impairing effect wears off, possibly as a result of tolerance.
Adult persons with intellectual disabilities on the island of Ireland
Authors: McConkey R. , Mulvany F. , Barron S.
Published: November 2005

Background  Information on the numbers of adult persons (aged 20 years and over) with intellectual disability (ID) is rarely collated at a national level. This is an impediment to service planning especially for a changing population.

Methods  A database of all persons in receipt of ID services has been operating in the Republic of Ireland since 1995. In Northern Ireland, regional databases can be used to provide similar information.

Results  A total of 25 134 persons were known to services in 2002; an overall prevalence for the island of 6.34 per 1000. However this rate varied for different age groupings and across the two parts of the island. General population characteristics, as well as service factors, appear to account for this. Significantly more people lived with family carers in Northern Ireland. By 2021, it was estimated that the population would increase by over 20% with around one‐third of persons aged over 50 years.

Conclusions  These data illustrate the variations that exist in the numbers of adult persons with ID known to services across and within regions of a country. Hence caution must be exercised in extrapolating prevalence rates derived in one area to another. The availability of comparative national data highlights issues around the equitable funding and delivery of services.
Living conditions of adults with intellectual disabilities from a gender perspective
Authors: Umb‐Carlsson Õ. , Sonnander K.
Published: November 2005

Background The role of gender has been a neglected issue in research on intellectual disability (ID). People with ID are generally treated as a homogenous group that are largely categorized by their level of ID. This study compared living conditions of women and men with ID and related the results to similarities and differences among the general population in corresponding age groups.

Methods Persons with ID born in Uppsala County between 1959 and 1974 constituted the study sample. Information on the living conditions of 110 persons with ID was collected using questionnaires completed by relatives and staff. Information on living conditions of the general population was obtained through national welfare statistics conducted by Statistics Sweden (SCB).

Results In both samples corresponding diversities were revealed for type of employment/daily activities, where women worked in traditional female job sectors and men were occupied with traditional male jobs. Women and men with ID participated to about the same extent in recreational and cultural activities and on only four of the 19 activities listed in the questionnaire (visits to the cinema and library, reading books and practising hobbies alone) significant differences were observed. Among women and men in the general population, we found gender‐related differences in 13 of the activities listed. However, with the exception of women more frequently visiting the library and reading books, the two samples demonstrated no corresponding gender‐related differences. For the remaining six domains (finances, family and social relations, housing, transport, community participation and personal safety), no differences were noted between women and men with ID. This finding contrasted sharply with the differences found between women and men in the general population.

Conclusions Surprisingly, the comparison yielded few differences in living conditions between women and men with ID compared with those found in women and men of the general population. This finding suggests that people with ID were treated as gender‐neutral persons rather than as women and men with individual preferences and needs. Thus, it appears that having ID is a more important determinant than gender regarding living conditions for women and men with ID.
A cross‐sectional multivariate analysis of children's attitudes towards disabilities
Authors: Nowicki E. A.
Published: November 2005

Background  Past research has shown that children can be biased against peers with disabilities, but the association of attitudes with gender, age and disability preferences, as well as interactions between these variables, are unclear. The objectives of this study were to examine these issues in a cross‐sectional, split‐plot study to clarify: (1) if elementary school children's attitudes towards peers with disabilities are related to age, gender and type of disability; (2) if interactions between these variables exist; and (3) if convergent validity could be achieved across three theoretically linked dependent variables.

Methods  One hundred elementary school children between 4 and 10 years old were assessed for attitudes towards target children with no disability, a physical or an intellectual disability, and a combined intellectual/physical disability. Measures were completed in an interview format.

Results  Attitudes towards a target child with physical disabilities and a target child without disabilities did not differ. There was a significant interaction for age and disability. Attitudes towards target children with intellectual and intellectual/physical disabilities were negatively biased, and were negatively associated with age. Results were consistent across measures except for a main effect of gender in one measure and a gender by age interaction in another.

Conclusions  Children's attitudes appear to be associated with several factors, including age and the presence or absence of disability. Gender differences in attitudes may be because of gender‐based response biases rather than disability biases. Because of the multifaceted nature of childhood attitudes, cross‐sectional designs with several dependent and independent variables provide an opportunity to examine consistency of results across measures and potential interactions between factors that may not be uncovered when variables are examined in isolation.
MazG – a regulator of programmed cell death in Escherichia coli
Authors: Gross Miryam , Marianovsky Irina , Glaser Gad
Published: November 2005

We have previously reported that mazEF, the first regulatable chromosomal ‘addiction module’ located on the Escherichia coli chromosome, downstream from the relA gene, plays a crucial role in the programmed cell death in bacteria under stressful conditions. It consists of a pair of genes encoding a stable toxin, MazF, and MazE, a labile antitoxin interacting with MazF to form a complex. The cellular target of MazF toxin was recently described to be cellular mRNA, which is degraded by this toxin. On the same operon, downstream to the mazEF genes, we found another open reading frame, which was called mazG. Recently, it was shown that the MazG protein has a nucleotide pyrophosphohydrolase activity. Here we show that mazG is being transcribed in the same polycistronic mRNA with mazEF. We also show that the enzymatic activity of MazG is inhibited by MazEF proteins. When the complex MazEF was added, the enzymatic activity of MazG was about 70% inhibited. We demonstrate that the enzymatic activity of MazG in vivo causes depletion of guanosine 3′,5′‐bispyrophosphate (ppGpp), synthesized by RelA under amino acid starvation conditions. Based on our results, we propose a model in which this third gene, which is unique for chromosomal addiction systems, has a function of limiting the deleterious activity of MazF toxin. In addition, MazG solves a frequently encountered biological problem: how to avoid the persistence of a toxic product beyond the time when its toxicity is useful to the survival of the population.
Borrelia burgdorferi bb0728 encodes a coenzyme A disulphide reductase whose function suggests a role in intracellular redox and the oxidative stress response
Authors: Boylan Julie A. , Hummel Charles S. , Benoit Stéphane , Garcia‐Lara Jorge , Treglown‐Downey Jennifer , Crane Edward J. , Gherardini Frank C.
Published: November 2005

The cellular responses of Borrelia burgdorferiTo reactive oxygen species (ROS) encountered during the different stages of its infective cycle are poorly understood. Few enzymes responsible for protecting proteins, DNA/RNA and lipids from damage by ROS have been identified and characterized. Data presented here suggest that bb0728 encodes an enzyme involved in this process. Biochemical analyses on purified recombinant BB0728 indicated that it functioned as a coenzyme A disulphide reductase (CoADR) (specific activity ≈ 26 units per mg of protein). This enzyme was specific for coenzyme A (CoA) disulphide, required NADH and had no significant activity against other disulphides, such as oxidized glutathione or thioredoxin. The high intracellular concentration of reduced CoA (CoASH) in B. burgdorferi cells (∼1 mM) and absence of glutathione suggest that CoA is the major low‐molecular‐weight thiol in this spirochete. Interestingly, CoASH was able to reduce H2O2 and be regenerated by CoADR suggesting one role for the system may be to protect B. burgdorferi from ROS. Further, mobility‐shift assays and transcriptional fusion data indicated that bb0728 was positively regulated by the Borrelia oxidative stress response regulator, BosR. Taken together, these data suggest a role for BB0728 in intracellular redox and the oxidative stress response in B. burgdorferi.
Biogeography and comparative ecology of testate amoebae inhabitingSphagnum‐dominated peatlands in the Great Lakes and Rocky Mountain regions of North America
Authors: Booth Robert K. , Zygmunt Jennifer R.
Published: November 2005

Testate amoebae (Protozoa: Rhizopoda) are common inhabitants of peatlands. Strong relationships between community composition and substrate moisture inSphagnum‐dominated peatlands have made them particularly useful as hydrological proxies in environmental and palaeoenvironmental research. However, stability of these relationships in geographical space is important for widespread applicability. In this study, we compared testate amoeba communities inhabitingSphagnum‐dominated peatlands of the Great Lakes and Rocky Mountain regions of North America. Our primary objectives were to describe patterns of community composition in the two regions, develop hypotheses to explain differences, and determine if taxa occupy similar ecological niches with respect to substrate moisture in both places. Our results indicated that testate amoeba communities are relatively different in the two regions, and these differences are probably caused by differences in climate and peatland trophic status, although other factors may also play a role. However, many taxa do occur in both regions and these taxa had comparable moisture preferences in each region, suggesting that the ecological niches of taxa with respect to substrate moisture are similar even within communities of relatively different composition.
Ecological boundary detection using Carlin–Chib Bayesian model selection
Authors: Nally Ralph Mac
Published: November 2005

Sharp ecological transitions in space (ecotones, edges, boundaries) often are where ecologically important events occur, such as elevated or reduced biodiversity or altered ecological functions (e.g. changes in productivity, pollination rates or parasitism loads, nesting success). While human observers often identify these transitions by using intuitive or gestalt assignments (e.g. the boundary between a remnant woodland patch and the surrounding farm paddock seems obvious), it is clearly desirable to make statistical assessments based on measurements. These assessments often are straightforward to make if the data are univariate, but identifying boundaries or transitions using compositional or multivariate data sets is more difficult. There is a need for an intermediate step in which pairwise similarities between points or temporal samples are computed. Here, I describe an approach that treats points along a transect as alternative hypotheses (models) about the location of the boundary. Carlin and Chib (1995) introduced a Bayesian technique for comparing non‐hierarchical models, which I adapted to compute the probabilities of each boundary location (i.e. a model) relative to the ensemble of models constituting the set of possible points of the boundary along the transect. Several artificial data sets and two field data sets (on vegetation and soils and on cave‐dwelling invertebrates and microclimates) are used to illustrate the approach. The method can be extended to cases in with several boundaries along a gradient, such as where there is an ecotone of non‐zero thickness.
Habitat and integration within indigenous communities of Xeropicta derbentina (Gastropoda: Hygromiidae) a recently introduced land snail in south‐eastern France
Authors: Aubry Sébastien , Labaune Corinne , Magnin Frédéric , Kiss Laurence
Published: November 2005

Xeropicta derbentina is a recently introduced land snail in Provence, France. The present work aims at describing the habitats and the land snail communities that it has invaded. Also, its impact on the species richness and diversity of indigenous communities is assessed. Two areas have been studied in order to cover the range of conditions that X. derbentina is encountering within its current French distribution. Sixty‐five samples were analysed from the most Mediterranean site, Auriol, and 140 from a northern site, Craus de St‐Michel‐l’Observatoire. From these samples, X. derbentina is found to be a thermophilous open‐land species mostly inhabiting human‐impacted habitats. It occurs in large populations (more than 100 individuals collected in 15 min) in habitat characterizing the first stages of secondary successions, from cultivated crops to dense fallow lands. However, within a heterogeneous landscape and if enough time has allowed its dispersal, X. derbentina can be found in almost any kinds of habitat, such as garrigues and woodlands. Consequently, X. derbentina occurs in diverse land snail communities. At the local scale, its large populations could result in a significant decrease in species richness and diversity. At the regional scale, however, the introduction of X. derbentina seems to have increased land snail species richness.
Endemism and sexual systems in the evergreen tree flora of the Western Ghats, India
Authors: Krishnan Rani M. , Ramesh B. R.
Published: November 2005

This study reports the endemism and sexual system in the wet evergreen tree flora of the Western Ghats. A total of 656 species from 66 families and 231 genera were listed. This included a gymnosperm family (Podocarpaceae) and a monocot family (Arecaceae). No family was endemic to the Western Ghats, but 352 species (53%) from 43 families and five genera were endemic. Nearly 35% of the families had no endemics. The largest families with endemics were Dipterocarpaceae (92%), Anacardiaceae (84%), Lauraceae (72%), Fabaceae, Rubiaceae and Myrtaceae (68%). The top five contributing families in the tree flora of the Western Ghats were Euphorbiaceae, Lauraceae, Rubiaceae, Myrtaceae and Annonaceae. The 656 species were largely hermaphrodites (57%) followed by dioecious (20%), polygamous (16%) and monoecious species (5%). The rate of dioecy reported in this study (20%) is higher than reports for Puerto Rico (18%) but lower than the Malaysian rainforest (26%). Structurally, like the Neotropical forests, most evergreen forest types of the Western Ghats could be classified into four ensembles. Yet, the Western Ghats had fewer species than other tropical and Neotropical forests. The proportion of endemics in the ensembles of the Western Ghats ranged from 34% (ensemble IV) to 14% (ensemble I).
Factors affecting plant diversity during post‐fire recovery and succession of mediterranean‐climate shrublands in California, USA
Authors: Keeley Jon E. , Fotheringham C. J. , Baer‐Keeley Melanie
Published: November 2005

Plant community diversity, measured as species richness, is typically highest in the early post‐fire years in California shrublands. However, this generalization is overly simplistic and the present study demonstrates that diversity is determined by a complex of temporal and spatial effects. Ninety sites distributed across southern California were studied for 5 years after a series of fires. Characteristics of the disturbance event, in this case fire severity, can alter post‐fire diversity, both decreasing and increasing diversity, depending on life form. Spatial variability in resource availability is an important factor explaining patterns of diversity, and there is a complex interaction between landscape features and life form. Temporal variability in resource availability affects diversity, and the diversity peak in the immediate post‐fire year (or two) appears to be driven by factors different from subsequent diversity peaks. Early post‐fire diversity is influenced by life‐history specialization, illustrated by species that spend the bulk of their life cycle as a dormant seed bank, which is then triggered to germinate by fire. Resource fluctuations, precipitation in particular, may be associated with subsequent post‐fire diversity peaks. These later peaks in diversity comprise a flora that is compositionally different from the immediate post‐fire flora, and their presence may be due to mass effects from population expansion of local populations in adjacent burned areas.
Variance components analyses of multiple asthma traits in a large sample of Australian families ascertained through a twin proband
Authors: Ferreira M. A. R. , O'Gorman L. , Souëf P. Le , Burton P. R. , Toelle B. G. , Robertson C. F. , Martin N. G. , Duffy D. L.
Published: November 2005

Background:  Intermediate phenotypes are often measured as a proxy for asthma. It is largely unclear to what extent the same set of environmental or genetic factors regulate these traits.

Objective:  Estimate the environmental and genetic correlations between self‐reported and clinical asthma traits.

Methods:  A total of 3073 subjects from 802 families were ascertained through a twin proband. Traits measured included self‐reported asthma, airway histamine responsiveness (AHR), skin prick response to common allergens including house dust mite (Dermatophagoides pteronyssinus [D. pter]), baseline lung function, total serum immunoglobulin E (IgE) and eosinophilia. Bivariate and multivariate analyses of eight traits were performed with adjustment for ascertainment and significant covariates.

Results:  Overall 2716 participants completed an asthma questionnaire and 2087 were clinically tested, including 1289 self‐reported asthmatics (92% previously diagnosed by a doctor). Asthma, AHR, markers of allergic sensitization and eosinophilia had significant environmental correlations with each other (range: 0.23–0.89). Baseline forced expiratory volume in 1 s (FEV1) showed low environmental correlations with most traits. Fewer genetic correlations were significantly different from zero. Phenotypes with greatest genetic similarity were asthma and atopy (0.46), IgE and eosinophilia (0.44), AHR and D. pter (0.43) and AHR and airway obstruction (−0.43). Traits with greatest genetic dissimilarity were FEV1 and atopy (0.05), airway obstruction and IgE (0.07) and FEV1 and D. pter (0.11).

Conclusion:  These results suggest that the same set of environmental factors regulates the variation of many asthma traits. In addition, although most traits are regulated to great extent by specific genetic factors, there is still some degree of genetic overlap that could be exploited by multivariate linkage approaches.
Common sex-linked deleterious alleles in a plant parasitic fungus alter infection success but show no pleiotropic advantage
Authors: Giraud T. , Jonot O. , Shykoff J. A.
Published: November 2005

Microbotryum violaceum is a fungus that causes the sterilizing anther smut disease in Caryophyllaceae. Its diploid teliospores normally produce equal proportions of haploid sporidia of its two mating types. However natural populations contain high frequencies of individuals producing sporidia of only one mating type (‘biased strains’). This mating type-ratio bias is caused by deleterious alleles at haploid phase (‘haplo-lethals’) linked to the mating type locus that can be transmitted only by intra-tetrad selfing. We used experimental inoculations to test some of the hypotheses proposed to explain the maintenance of haplo-lethals. We found a disadvantage of biased strains in infection ability and high intra-tetrad mating rates. Biased strains had no higher competitive ability nor shorter latency and their higher spore production per flower appeared insufficient to compensate their disadvantages. These findings were only consistent with the hypothesis that haplo-lethals are maintained under a metapopulation structure because of high intra-tetrad selfing rates, founder effects and selection at the population level.
Phylogeography and alpha taxonomy of the common dolphin (Delphinus sp.)
Authors: Natoli A. , Cañadas A. , Peddemors V. M. , Aguilar A. , Vaquero C. , Fernández-Piqueras P. , Hoelzel A. R.
Published: November 2005

The resolution of taxonomic classifications for delphinid cetaceans has been problematic, especially for species in the genera Delphinus, Tursiops and Stenella. The frequent lack of correspondence between morphological and genetic differentiation in these species raises questions about the mechanisms responsible for their evolution. In this study we focus on the genus Delphinus, and use molecular markers to address questions about speciation and the evolution of population structure. Delphinus species have a worldwide distribution and show a high degree of morphological variation. Two distinct morphotypes, long-beaked and short-beaked, have been considered different species named D. capensis and D. delphis, respectively. However, genetic differentiation between these two forms has only been demonstrated in the Pacific. We analysed samples from eight different geographical regions, including two morphologically defined long-beaked form populations, and compared these with the eastern North Pacific populations. We found high differentiation among the populations described as long-beaked instead of the expected monophyly, suggesting that these populations may have evolved from independent events converging on the same morphotype. We observed low genetic differentiation among the short-beaked populations across a large geographical scale. We interpret these phylogeographical patterns in the context of life history and population structure in related species.
Recombinant activated factor VII (rFVIIa/NovoSeven®) in intractable haemorrhage: use of a clinical scoring system to predict outcome
Authors: Biss T. T. , Hanley J. P.
Published: November 2005

Background and Objectives  Recombinant activated factor VII (rFVIIa/NovoSeven®) has been advocated in the treatment of life‐threatening haemorrhage, but appropriate clinical indications remain uncertain. The aim of this study was to detect factors predictive of outcome and to incorporate them into a prognostically significant scoring system.

Materials and Methods  Thirty‐six patients received rFVIIa for uncontrolled surgical, traumatic or obstetric bleeding in the Northern Region of the UK over a 45‐month period. Clinical, laboratory and outcome data were examined. Characteristics of survivor and non‐survivor groups were compared. A prognostic scoring system was evaluated retrospectively according to the presence of coagulopathy, renal impairment, hypothermia, greater than 10 units of red cell transfusion, advanced age and obstetric indication, with patients allocated to low, intermediate and high‐risk groups.

Results  Clinical response occurred in 26 patients (72%) with a reduction in prothrombin time and blood product requirements. Death occurred in 19 (53%). Four patients (11%) suffered thrombotic events. Survivors were younger than non‐survivors and less likely to have coagulopathy, renal impairment or hypothermia at the time of administration. Survivors were more likely to have had an initial clinical response in terms of an immediate reduction in haemorrhage. Non‐survivors were transfused a greater number of red cell units prior to administration. Survival varied according to prognostic score; low‐risk patients had a survival rate of 85%, intermediate‐risk patients had a survival rate of 50% and high‐risk patients had a survival rate of 18%.

Conclusions  FVIIa has a role in the cessation of haemorrhage, but may not improve survival. Use of a clinical scoring system may help to predict outcome.
The Central Retinal Artery and Regression of the Hyaloid Artery in Perinatal Cattle
Authors: Ö Zcan S. , KürtÜl İ. , Aksoy G. , Aslan K.
Published: November 2005

The arterial supply to the retina and lens of 10 fetal, 10 neonatal and four adult Zavot‐bred cattle of both sexes was studied macroscopically and by stereoscopic microscopy by means of vascular perfusion with latex, giving special emphasis on the hyaloid artery. The central retinal artery ramified in four major retinal arterioles, which formed a compact network throughout the retina (holangiotic or euangiotic pattern). The hyaloid artery was patent in all fetal stages and extended through the vitreous cavity of the eye to the caudal surface of the capsule of the lens. Atrophy of the hyaloid artery began immediately after birth and was completed on day 17 after parturition. No remnant of the hyaloid artery in the vitreous cavity was observed in the adult cattle examined at stereoscopic microscopic level.
The Presence of Megamitochondria in the Ellipsoid of Photoreceptor Inner Segment of the Zebrafish Retina
Authors: Kim J. , Lee E. , Chang B. S. , Oh C. S. , Mun G.‐H. , Chung Y. H. , Shin D. H.
Published: November 2005

Although the megamitochondria (MM) were localized in various pathological conditions, normal retina of some mammalian species was reported to include MM for various physiological roles. However, it was not clearly confirmed whether the MM is present in the retina of lower vertebrate as well. In this study, we tried to show the presence of the MM in the zebrafish retina using electron microscopic technique. In all the photoreceptors including rods, cones and double cones of the zebrafish retina, MM were observed in the ellipsoid of inner segment. In the photoreceptor epllipsoid of the zebrafish retina, the mitochondria located in the central portion of the ellipsoid had a highly electron‐dense matrix, which were accompanied by the mitochondria with electron‐lucent matrix in the apical portion of the ellipsoid. The presence of MM was more clearly discernable in the rods, which were localized under the double cones. This finding is somewhat different from those observed in the previous studies because MM were localized in the inner segment of cones, but were not in those of rods in the case of mammalian retina. Although the exact physiological meaning for the presence of MM in some vertebrate species should be further studied, the present study could show that the MM in the ellipsoid of the retinal photoreceptors was not only restricted in some mammalian species.
Morphological and Immunocytochemical Investigations on Mast Cells in Porcine Ureter
Authors: Vodenicharov A. , Leiser R. , Gulubova M. , Vlaykova T.
Published: November 2005

Morphological, morphometric, histochemical and immunocytochemical investigations on mast cells, located in the wall of ureter of 8 months aged pigs were performed. Mast cells were found in all three layers of ureteral wall, but their distribution was irregular and the number unequal. It was established that alcian blue (AB)‐positive mast cells were significantly more than toluidine blue (TB)‐positive mast cells. A statistically significant smaller number of both AB and TB‐stained mast cells were observed in the tunica mucosa. The largest number of mast cells was found in the tunica muscularis. In the adventitia, mast cells were higher in number in the main connective tissue than in the connective tissue near the blood vessels. Mast cells stained with TB showed variably expressed γ‐metachromasia, which was best visible in those situated in the lamina propria of the mucosa. The prevailing parts of mast cells, however, were AB‐positive after AB‐safranin staining. This was mostly found in mast cells of the tunica muscularis and in mast cells of perivascular location in the tunica adventitia. Immunocytochemically, mast cells were found to be positive for histamine and vasoactive intestinal polypeptide in the muscle coat, and to histamine in the adventitia, as well. On the basis of obtained results it was presumed that the mast cells in porcine ureter most probably took part not only in keeping of local homeostasis, but played also an important role of mobility of smooth muscle cells in the middle layer of ureter on one hand, and, on the other, in the adventitial blood vessels.
Serotonin‐Containing Cells in the Gastrointestinal Tract of Newborn Foals and Adult Horses
Authors: Fink C. , Tatar M. , Failing K. , Hospes R. , Kressin M. , Klisch K.
Published: November 2005

Serotonin (5‐hydroxytryptamine, 5‐HT), a regulatory amine of mucosal enterochromaffin cells plays an important role in the control of gastrointestinal smooth muscle contraction and epithelial secretion. Serotonin has also been associated with gastric ulcers, diarrhoea and abdominal pain. In spite of the high incidence of these gastrointestinal disorders in newborn foals and adult horses, no data are available regarding 5‐HT immunoreactive cells (i.c.) in the gastrointestinal tract (GIT) of foals, and for adult horses, data are incomplete and contradictory. In this study, the distribution and relative frequency of 5‐HT i.c. in the GIT of newborn foals and adult horses were determined immunohistochemically. In foals as in adults, a relatively large number of 5‐HT i.c. were detected in all portions of the GIT. In foals, a significantly higher amount of cells was found in the pyloric region and margo plicatus of the stomach, as well as in the caecum and colon ascendens compared with adults. Our results provided rationale for further research concerning the role of 5‐HT i.c. during the milk diet or in the regulation of gastrointestinal growth/cell proliferation, and in the pathogenesis of gastric ulcers, especially in newborn foals.