bluuebunny/crossref_metadata_2025 huggingface dataset:
The role of repulsive guidance molecules in the embryonic and adult vertebrate central nervous system
Authors: Mueller Bernhard K , Yamashita Toshihide , Schaffar Gregor , Mueller Reinhold
Published: August 2006

During the development of the nervous system, outgrowing axons often have to travel long distances to reach their target neurons. In this process, outgrowing neurites tipped with motile growth cones rely on guidance cues present in their local environment. These cues are detected by specific receptors expressed on growth cones and neurites and influence the trajectory of the growing fibres. Neurite growth, guidance, target innervation and synapse formation and maturation are the processes that occur predominantly but not exclusively during embryonic or early post-natal development in vertebrates. As a result, a functional neural network is established, which is usually remarkably stable. However, the stability of the neural network in higher vertebrates comes at an expensive price, i.e. the loss of any significant ability to regenerate injured or damaged neuronal connections in their central nervous system (CNS). Most importantly, neurite growth inhibitors prevent any regenerative growth of injured nerve fibres. Some of these inhibitors are associated with CNS myelin, others are found at the lesion site and in the scar tissue. Traumatic injuries in brain and spinal cord of mammals induce upregulation of embryonic inhibitory or repulsive guidance cues and their receptors on the neurites. An example for embryonic repulsive directional cues re-expressed at lesion sites in both the rat and human CNS is provided with repulsive guidance molecules, a new family of directional guidance cues.
Plasticity of connections underlying locomotor recovery after central and/or peripheral lesions in the adult mammals
Authors: Rossignol Serge
Published: August 2006

This review discusses some aspects of plasticity of connections after spinal injury in adult animal models as a basis for functional recovery of locomotion. After reviewing some pitfalls that must be avoided when claiming functional recovery and the importance of a conceptual framework for the control of locomotion, locomotor recovery after spinal lesions, mainly in cats, is summarized. It is concluded that recovery is partly due to plastic changes within the existing spinal locomotor networks. Locomotor training appears to change the excitability of simple reflex pathways as well as more complex circuitry. The spinal cord possesses an intrinsic capacity to adapt to lesions of central tracts or peripheral nerves but, as a rule, adaptation to lesions entails changes atbothspinal and supraspinal levels. A brief summary of the spinal capacity of the rat, mouse and human to express spinal locomotor patterns is given, indicating that the concepts derived mainly from work in the cat extend to other adult mammals. It is hoped that some of the issues presented will help to evaluate how plasticity of existing connections may combine with and potentiate treatments designed to promote regeneration to optimize remaining motor functions.
Neurotrophin-regulated signalling pathways
Authors: Reichardt Louis F
Published: August 2006

Neurotrophins are a family of closely related proteins that were identified initially as survival factors for sensory and sympathetic neurons, and have since been shown to control many aspects of survival, development and function of neurons in both the peripheral and the central nervous systems. Each of the four mammalian neurotrophins has been shown to activate one or more of the three members of the tropomyosin-related kinase (Trk) family of receptor tyrosine kinases (TrkA, TrkB and TrkC). In addition, each neurotrophin activates p75 neurotrophin receptor (p75NTR), a member of the tumour necrosis factor receptor superfamily. Through Trk receptors, neurotrophins activate Ras, phosphatidyl inositol-3 (PI3)-kinase, phospholipase C-γ1 and signalling pathways controlled through these proteins, such as the MAP kinases. Activation of p75NTR results in activation of the nuclear factor-κB (NF-κB) and Jun kinase as well as other signalling pathways. Limiting quantities of neurotrophins during development control the number of surviving neurons to ensure a match between neurons and the requirement for a suitable density of target innervation. The neurotrophins also regulate cell fate decisions, axon growth, dendrite growth and pruning and the expression of proteins, such as ion channels, transmitter biosynthetic enzymes and neuropeptide transmitters that are essential for normal neuronal function. Continued presence of the neurotrophins is required in the adult nervous system, where they control synaptic function and plasticity, and sustain neuronal survival, morphology and differentiation. They also have additional, subtler roles outside the nervous system. In recent years, three rare human genetic disorders, which result in deleterious effects on sensory perception, cognition and a variety of behaviours, have been shown to be attributable to mutations in brain-derived neurotrophic factor and two of the Trk receptors.
Sludge‐derived organic carbon in an agricultural soil estimated by 13C abundance measurements
Authors: Parat C. , Leveque J. , Chaussod R. , Andreux F.
Published: August 2006

The objective of this study is to develop a method to follow the dynamics of sludge‐derived organic carbon, which will allow us to understand the behaviour of trace metals in the sludge‐treated soils. We studied, in a sandy agricultural soil of southwest France, cultivated with maize and amended with sewage‐sludge over 20 years, the dynamics of different sources of organic matter and compared this with a control, which had never received any treatment. For the first time, a method is proposed that will distinguish and quantify sludge‐derived organic carbon, maize‐derived organic carbon, and native organic carbon. This method is based on the mean differences in δ13C abundances between native (−26.5‰), maize (−12.5‰) and sludge (−25.4‰) organic carbon. Three hypotheses on the dynamics of soil organic matter sources are proposed: (i) isotopic differences observed between control and sludge‐treated soils are due only to the incorporation of sludge C, whereas in the others, the control was used to model the incorporation of (ii) maize C or (iii) native C in the sludge‐treated soils. The comparison of the stocks of each source (native C, maize C and sludge C) found in the bulk soil with the sum of corresponding stocks found in particle‐size fractions allowed us to reject the two first hypotheses and to validate the last one. Repeated applications of sewage‐sludge induced accumulation of sludge‐derived organic carbon in the topsoil, and simultaneously contributed to the preservation of maize‐derived organic carbon. When sludge applications ceased, the rapid decrease in soil organic matter stocks was mostly caused by the degradation of the sludge‐derived organic carbon sources. At the same time, the maize‐derived organic carbon shifted from the coarsest fraction (200–2000 μm) to the finest fraction (0–50 μm). Therefore, this study has shown that repeated applications of sewage‐sludge induced changes in soil organic matter dynamics over time.
Relation of dispersivity to properties of homogeneous saturated repacked soil columns
Authors: Bromly M. , Hinz C. , Aylmore L. A. G.
Published: August 2006

It is expected that solute dispersivity is determined by the physical properties of the transport medium. However, experimental investigations to date have not identified such a relationship. In this work, we examine the relation between soil physical parameters, experimental parameters and dispersivity. Experimental data were compiled for 291 repacked, saturated homogeneous laboratory column experiments reported in the literature. Using multiple stepwise regression and classification and regression tree analysis, the relationships between soil physical parameters (sand, silt and clay content, bulk density, water content), experimental parameters (pore‐water velocity, column length and diameter), and transport parameters (dispersion coefficient and dispersivity) were examined. Regression tree analysis showed that clay content was the most important factor controlling dispersivity, followed by column diameter. Columns of length less than approximately 10 cm generally resulted in greater dispersivities than longer columns. A scale effect appeared significant with increasing column diameter, but was not apparent with column length. These results suggest that it may only be possible to relate dispersivity to intrinsic soil properties by explicitly accounting for the experimental design, including column geometry, inlet dead volume and soil packing.
Production and consumption of ethylene in temperate volcanic forest surface soils
Authors: Xu X. , Inubushi K.
Published: August 2006

To date our knowledge is limited with regard to the cycling of ethylene (C2H4) in temperate forest soils containing volcanic ash, and the effect of forest‐to‐orchard conversion on its cycling. We studied ethylene accumulation in such forest soils by oxic and anoxic incubations, along with the stimulatory effect of glucose addition on soil C2H4 accumulation. We also studied the effect of antibiotics and autoclaving on C2H4 production and consumption by volcanic forest soils, and the cycling of C2H4 and CH4 in surface soils after conversion of a Japanese cedar forest to an orchard. Ethylene production and consumption by forest surface soils results from a microbial process, and soil streptomycin‐sensitive bacteria make a minor contribution. Soil C2H4 accumulation was much larger during anoxic than during oxic incubation, which indicates that anoxic conditions can induce C2H4 accumulation in forest soils. Glucose addition as a carbon source can sharply increase C2H4 accumulation rates in the anoxic and oxic forest soils during the first week of incubation. However, there was no difference in total C2H4 accumulation in the amended and non‐treated soils after 35 days of anoxic incubation. Ethylene production of the 0–5 cm and 5–10 cm soils beneath forest and orchard showed the greatest rate after 2 weeks of anoxic incubation when soil CH4 production started to increase sharply, and later it was strongly suppressed. The forest‐to‐orchard conversion showed little influence on the CH4 production of surface soils during short‐term anoxic incubation, but significantly reduced soil C2H4 production. The conversion also significantly decreased the consumption of soil CH4 and C2H4, the former more than the latter. Soil properties such as total C, water‐soluble organic C and pH contribute to the consumption and production of C2H4 in the 0–5 cm and 5–10 cm soils, and there are the parallels between CH4 and C2H4 consumption in soils, which suggests the presence of similar microorganisms. Long‐term anoxic conditions of in situ surface upland soils are normally not prevalent, so it can be reasonably concluded that there is a larger C2H4 accumulation rather than CH4 accumulation in surface soils beneath forest and orchard after heavy rainfall, especially beneath forest.
Measured soil organic matter fractions can be related to pools in the RothC model
Authors: Zimmermann M. , Leifeld J. , Schmidt M. W. I. , Smith P. , Fuhrer J.
Published: August 2006

Understanding the response of soil organic carbon (SOC) to environmental and management factors is necessary for estimating the potential of soils to sequester atmospheric carbon. Changes over time in the amount and distribution of SOC fractions with different turnover rates can be estimated by means of soil SOC models such as RothC, which typically consider two to five SOC pools. Ideally, these pools should correspond to measurable SOC fractions. The aim of this study was to test the relationship between SOC pools used in RothC and fractions separated through a fractionation procedure. A total of 123 topsoil samples from agricultural sites (arable land, grassland and alpine pasture) across Switzerland were used. A combination of physical and chemical methods resulted in two sensitive (particulate organic matter and dissolved organic carbon), two slow (carbon associated to clay and silt or stabilized in aggregates) and one passive (oxidation‐resistant carbon) SOM fractions. These fractions were compared with the estimated equilibrium model pools when the corresponding soils were modelled with RothC. Analysis revealed strong correlations between SOC in measured fractions and modelled pools. Spearman’s rank correlation coefficients varied between 0.82 for decomposable plant materials (DPM), 0.76 for resistant plant materials (RPM), 0.99 for humified organic matter (HUM) and biomass (BIO), and 0.73 for inert organic matter (IOM). The results show that the proposed fractionation procedure can be used with minor adaptations to identify measurable SOC fractions, which can be used to initialize and evaluate RothC for a wide range of site conditions.
Dissolved organic carbon interactions with sorption and leaching of diuron in organic‐amended soils
Authors: Cox L. , Velarde P. , Cabrera A. , Hermosín M. C. , Cornejo J.
Published: August 2006

Diuron (N′‐[3,4‐dichlorophenyl]‐N,N‐dimethylurea) is one of the most frequently used herbicides in olive groves in Spain and other Mediterranean countries. The main objective of this work was to investigate the effect of the dissolved organic carbon (DOC) from a commercial humic amendment, derived by composting the liquid waste of the olive‐mill process (LF), and a solid residue from the olive oil production industry (AL) on the sorption and leaching behaviour of diuron in soil. For this purpose, a clay and a sandy soil were selected. Soil sorption coefficients of diuron increased with LF (32%) and AL (76%) amendment in the sandy soil, whereas sorption decreased in the clay soil upon amendment, especially in the case of the liquid LF (52%). The DOC from LF and AL is composed of very poorly humified molecules, which are strongly sorbed onto the clay soil and thus compete with diuron for the same sorption sites. Dialysis experiments revealed that diuron forms stable complexes with DOC from LF and AL. Leaching of diuron in columns of the sandy soil treated with the organic amendments caused earlier breakthrough and maximum concentration peaks at fewer pore volumes when compared with leaching with 0.01 m CaCl2. Competition between diuron and DOC molecules for sorption sites and diuron–DOC interactions can both account for the enhanced leaching of diuron.
Louisiana waterthrushes (Seiurus motacilla) and habitat assessments as cost‐effective indicators of instream biotic integrity
Authors: MATTSSON B. J. , COOPER R. J.
Published: August 2006

1. Benthic stream animals, in particular macroinvertebrates, are good indicators of water quality, but sampling can be laborious to obtain accurate indices of biotic integrity. Thus, tools for bioassessment that include measurements other than macroinvertebrates would be valuable additions to volunteer monitoring protocols.

2. We evaluated the usefulness of a stream‐dependent songbird, the Louisiana waterthrush (waterthrush,Seiurus motacilla) and the Environmental Protection Agency Visual Habitat Assessment (EPA VHA) as indicators of the macrobenthos community in headwater streams of the Georgia Piedmont, U.S.A. We sampled macrobenthos, surveyed waterthrushes and measured habitat characteristics along 39 headwater reaches across 17 catchments ranging from forested to heavily urbanised or grazed by cattle.

3. Of the indicators considered, waterthrush occupancy was best for predicting relative abundances of macrobenthic taxa, while the EPA VHA was best for predicting Ephemeroptera–Plecoptera–Trichoptera (EPT) richness. Individual components of EPA VHA scores were much less useful as indicators of EPT richness and % EPT when compared with the total score. Waterthrushes were found along streams with higher % EPT, a lower Family Biotic Index (FBI) values and greater macrobenthos biomass.

4. While macroinvertebrates remain one of the most direct indicators of stream water quality, stream bird surveys and reach‐scale habitat assessments can serve as cost‐effective indicators of benthic macroinvertebrate communities. Using stream‐dependent birds as an early warning signal for degradation of stream biotic integrity could improve the efficacy of catchment monitoring programmes in detecting and identifying perturbations within the catchment.
Leaf litter flammability in some semi‐arid Australian woodlands
Authors: SCARFF F. R. , WESTOBY M.
Published: August 2006

Wildfires strongly influence the biotic composition and carbon cycle of many ecosystems. Plant species provide the fuel for wildfires, but vary widely in their flammability. This study aimed to determine what plant characteristics control leaf litter flammability and to clarify how they are related to other functional traits.

Litter flammability varied across 14 tree species occurring in a mosaic of five floristic associations.

Differences in heat‐release rate between species were driven by leaf size, from small‐leaved conifers, casuarinas and acacias to large‐leaved eucalypts andBrachychiton.

Large leaves created an open litter‐bed structure that burned more rapidly because it was better ventilated. The results on heat‐release rate were partitioned according to fundamental principles for the transport of oxygen through a packed fuel bed, showing that heat‐release rate scaled linearly with estimated gas‐flow rates, as expected in ventilation‐controlled fires.

Species that were able to resprout after fire had litter that burned more intensely and was more likely to sustain a spreading fire than litter from obligate seeders, and were correspondingly larger‐leaved.

Many fire‐prone wooded ecosystems in the region consist of large‐leaved resprouting tree species co‐occurring with small‐leaved obligate seeders.
Interaction of SPIN90 with syndapin is implicated in clathrin‐mediated endocytic pathway in fibroblasts
Authors: Kim Sung Hyun , Choi Hyun Jin , Lee Kyoung Woo , Hong Nan Hyung , Sung Bong Hwan , Choi Kyu Yeong , Kim Seon‐Myung , Chang Sunghoe , Eom Soo Hyun , Song Woo Keun
Published: August 2006

SPIN90, a 90‐kDa Nck‐interacting protein with a SH3 domain, plays a role in sarcomere formation and myofibril assembly, and its phosphorylation is modulated by cell adhesion and Erk activation. Here we demonstrate that SPIN90 participates in receptor‐mediated endocytic pathway in fibroblasts. We identified syndapin (synaptic dynamin‐binding protein) as a SPIN90 interacting protein using yeast two‐hybrid screening. SPIN90 directly binds the SH3 domain of syndapin via its proline rich domain in vitro and in vivo and also associates with clathrin. Over‐expression of SPIN90‐full length in COS‐7 cells inhibited transferrin uptake, a marker of endocytosis. Interestingly, SPIN90‐PRD, a syndapin‐binding domain, significantly inhibited endocytosis, and the inhibition was reversed by co‐expression of syndapin. Depleting SPIN90 through antibody microinjection or Knocking it down using siRNAs also significantly inhibited transferrin internalization. Moreover, early endosomal marker proteins (EEA1 and Rab5) appeared to closely associate or partially co‐localize with SPIN90 in endosomes and an internalized FITC‐dextran and Texas Red‐EGF were found on the endosomes in association with SPIN90. Time‐lapse video showed that GFP‐SPIN90 travels with moving vesicles within living cells. Taken together, these findings suggest that SPIN90 is implicated in receptor‐mediated endocytic pathway in fibroblasts.
Chromatin immunoprecipitation‐mediated target identification proved aquaporin 5 is regulated directly by estrogen in the uterus
Authors: Kobayashi Mika , Takahashi Eri , Miyagawa Shin‐ichi , Watanabe Hajime , Iguchi Taisen
Published: August 2006

Estrogens play a central role in the reproduction of vertebrates and affect a variety of biological processes. The major target molecules of estrogens are nuclear estrogen receptors (ERs), which have been studied extensively at the molecular level. In contrast, our knowledge of the genes that are regulated directly by ERs remains limited, especially at the level of the whole organism rather than cultured cells. In order to identify genes that are regulated directly by ERs in vivo, we used estrogen treated mouse uterus and performed chromatin immunoprecipitation. Sequence analysis of a precipitated DNA fragment enabled alignment with the mouse genomic sequence and revealed that the promoter region of the gene encoding aquaporin 5 (AQP5) was precipitated with antibody against ERα. Quantitative PCR and DNA microarray analyses confirmed that AQP5 is activated soon after administration of estrogen. In addition, the promoter region of AQP5 contained a functional estrogen response element that was activated directly by estrogen. Although several AQP genes are expressed in the uterus, only direct activation of AQP5 could be detected following treatment with estrogen. This chromatin immunopreciptation‐mediated target identification may be applicable to the study of other transcription factor networks.
Enhanced neutrophil motility by granulocyte colony‐stimulating factor: the role of extracellular signal‐regulated kinase and phosphatidylinositol 3‐kinase
Authors: Nakamae‐Akahori Mika , Kato Takayuki , Masuda Sayuri , Sakamoto Erina , Kutsuna Haruo , Hato Fumihiko , Nishizawa Yoshiki , Hino Masayuki , Kitagawa Seiichi
Published: August 2006

The effect of granulocyte colony‐stimulating factor (G‐CSF) on human neutrophil motility was studied using videomicroscopy. Stimulation of neutrophils with G‐CSF resulted in enhanced motility with morphological change and increased adherence. Enhanced neutrophil motility was detected within 3–5 min after G‐CSF stimulation, reached a maximum at 10 min, and was sustained for approximately 35 min. The maximum migration rate was 84·4 ± 2·9 μm/5 min. A study using the Boyden chamber method revealed that G‐CSF‐stimulated neutrophils exhibited random migration but not chemotaxis. Enhanced neutrophil motility and morphological change were inhibited by MEK [mitogen‐activated protein kinase (MAPK)/extracellular signal‐regulated kinase (ERK) kinase] inhibitors (PD98059 and U0126), and a phosphatidylinositol 3‐kinase (PI3K) inhibitor (wortmannin), but not by a p38 MAPK inhibitor (SB203580). These findings are consistent with the fact that G‐CSF selectively activates MEK/ERK and PI3K, but not p38, in neutrophils. MEK/ERK activation was associated with G‐CSF‐induced redistribution of F‐actin and phosphorylated myosin light chain. Enhanced neutrophil motility was observed even in the presence of neutralizing anti‐CD18 antibody, which prevented cell adherence. These findings indicate that G‐CSF induces human neutrophil migration via activation of MEK/ERK and PI3K.
Large‐scale expansion of rat CD4+ CD25+ Treg cells in the absence of T‐cell receptor stimulation
Authors: Beyersdorf Niklas , Balbach Karen , Hünig Thomas , Kerkau Thomas
Published: August 2006

T‐cell receptor (TCR) stimulation is both central to homeostatic maintenance of CD4+ CD25+ regulatory T cells (Treg cells) in vivo and a prerequisite for the initiation of suppression by Treg cells, both in vivo and in vitro. However, TCR‐independent stimulation of Treg cells, e.g. with superagonistic CD28‐specific monoclonal antibodies (CD28‐SA), not only expands these cells in vivo but, as we show here, also mediates large‐scale expansion of rat Treg cells in vitro. Interestingly, CD28‐SA stimulation plus interleukin (IL)‐2 was even superior to conventional costimulation plus IL‐2 in promoting Treg cell growth in vitro. Despite their highly activated phenotype suppression by Treg cells expanded in the absence of TCR stimulation remained fully dependent on TCR‐triggering for initiation and cell contact was required to exert suppression. With regard to the regulation of suppression by CD28 stimulation we observed that neither the presence of a conventional anti‐CD28 monoclonal antibody nor a CD28‐SA generally rendered conventional T cells resistant to suppression by preactivated Treg cells. Taken together, we provide a novel protocol for long‐term propagation of Treg cells in vitro and our data are the first to reveal a difference in the signals required for activation and expansion of Treg cells and those, involving the TCR, necessary for the initiation of suppression.
Pulpal anaesthesia for mandibular permanent first molar teeth: a double‐blind randomized cross‐over trial comparing buccal and buccal plus lingual infiltration injections in volunteers
Authors: Meechan J. G. , Kanaa M. D. , Corbett I. P. , Steen I. N. , Whitworth J. M.
Published: August 2006

Aim  To compare the efficacy of buccal and buccal plus lingual infiltration anaesthesia for permanent mandibular first molars.

Methodology  Thirty one healthy adult volunteers received each of the following methods of anaesthesia for a mandibular first molar tooth in a randomised order, 1) Buccal infiltration of 1.8 mL and needle penetration lingually. 2) Buccal infiltration of 0.9 mL, plus lingual infiltration of 0.9 mL. Two percent lidocaine with 1:100,000 epinephrine was used. Electrical pulp testing was performed before, and every 2 minutes for 30 minutes after injection. A successful outcome was recorded as the absence of pulp sensation on two or more consecutive maximal pulp tester stimulations (80 μA). Injection discomfort was assessed using visual analogue scales. Data were compared with McNemar and Wilcoxon Signed Ranks tests.

Results  Buccal infiltration was successful in 38.7% of cases compared to 32.3% after combined infiltrations; the difference was not significant (P = 0.63). Buccal infiltration produced more episodes of no response to maximum stimulation than buccal and lingual infiltrations (129 and 114 respectively), this difference was not significant (P = 0.11). Peak anaesthetic effect occurred around 10–14 minutes after injection. There was no difference in injection discomfort between buccal injections of 0.9 mL and 1.8 mL of solution (P = 0.90). Lingual injection was more uncomfortable than lingual penetration (P = O.O02).

Conclusions  Buccal and buccal plus lingual infiltrations did not differ in their efficacy in producing anaesthesia of permanent first molar teeth.
Root canal treatment in Denmark is most often carried out in carious vital molar teeth and retreatments are rare
Authors: Bjørndal L. , Laustsen M. H. , Reit C.
Published: August 2006

Aim  To study the reasons given by a representative sample of Danish general dental practitioners (GDPs) for undertaking root canal treatment and, to investigate their confidence in performing root canal treatment on molar teeth.

Methodology  A questionnaire was sent to 600 Danish GDPs randomly selected from the roster of the Danish Dental Association. They were asked to recall various factors about their experience of the last root filling they completed, including the reason for treatment and the pulp diagnosis. Self‐assessments on 100‐mm visual analogue scales (VAS) were reported concerning the confidence in performing root canal treatment of a molar. End‐point definitions were ‘very easy’ (0) and ‘very difficult’ (100), respectively. Time reports of molar treatments were given in categorized groups.

Results  The most frequent reason for performing root canal treatment was caries within the tooth involved (55%). The majority of treatments involved teeth with vital pulps (54%). Retreatments were carried out in 2% of the cases. The confidence in performing root canal treatment varied but was relatively high, expressed as VAS‐values below 50. The creation of an aseptic working field was regarded as the most difficult procedure followed by root canal preparation. Fifty‐six percent of the responders stated a time frame of 46–75 min to complete root filling in a molar tooth.

Conclusions  Root canal treatment in Denmark was reported to be undertaken most often because of caries. Treatment was typically performed in molar teeth with vital pulp. Even though apical periodontitis was frequently noted in root filled teeth, retreatments were rare. From a subjective perspective root canal treatment was not considered to be very difficult and was carried out relatively rapidly.
Haemostatic agents used in periradicular surgery: an experimental study of their efficacy and tissue reactions
Authors: Von Arx T. , Jensen S. S. , Hänni S. , Schenk R. K.
Published: August 2006

Aim  To evaluate the haemostatic efficacy and the histologic tissue responses after the application of different haemostatic agents used in periradicular surgery.

Methodology  The study was conducted in the calvarium of six rabbits. Standardized bone defects (diameter 4 mm) were trephined, and different haemostatic agents were applied and compared with control defects: bone wax (left for 10 min), Stasis® (ferric sulphate, left for 5 s), ExpasylTM (aluminium chloride, left for 2 min and left permanently in situ), and a combination of ExpasylTM (2 min) and Stasis® (5 s). The sites were photographed before the application and after the removal of the haemostatic agents. Three independent examiners judged the initial and final bleeding (on the photographs) using a bleeding score for each site and treatment. The results were compared using Wilcoxon's signed rank test. For the histologic analysis, three animals were killed after 3 weeks and three animals after 12 weeks. Transverse, nondecalcified sections were stained with combined basic fuchsin and toluidine blue for descriptive histology.

Results  The most efficient haemorrhage control was provided by ExpasylTM in combination with Stasis® and by ExpasylTM alone, whereas bone wax had the weakest bleeding reduction effect. The histologic analysis after 3 weeks demonstrated an inflammatory and foreign body tissue response towards all haemostatic agents. At 12 weeks, this tissue response was less pronounced but still present in sites treated with bone wax or ExpasylTM. In general, the inflammatory tissue reactions were limited to the bone defects, and never extended into the surrounding tissues.

Conclusions  ExpasylTM alone or in combination with Stasis® appeared to be the most efficient of tested agents to control the bleeding within the bony defects created in a rabbit calvarium model.
Effects of luting agent and thermocycling on bond strengths to root canal dentine
Authors: Bitter K. , Meyer‐Lueckel H. , Priehn K. , Kanjuparambil J. P. , Neumann K. , Kielbassa A. M.
Published: August 2006

Aim  To investigate the effects of luting agent and thermocycling on bond strengths to root canal dentine.

Methodology  Extracted maxillary canines (n =144) were root filled and divided into six groups of 24 teeth each. Fibre posts (FRC Postec) were inserted using six luting agents: Panavia F, Multilink, Variolink II, PermaFlo DC, RelyX Unicem and Clearfil Core. Each root was sliced into six discs (thickness 1 mm) representing the coronal, middle and apical part of the root canal. Push‐out tests were performed 24 h after post insertion (n = 12) as well as after thermocycling (5000×; 5–55 °C, 30 s) (n = 12). Statistical analysis was conducted using analysis of variance (anova) followed by post‐hoc comparisons (Tukey‐B). The influence of thermocycling on bond strengths was investigated for each material and region separately using t‐tests.

Results  The bond strengths were significantly affected by the luting agent (P < 0.001), the root position (P = 0.003) and thermocycling (P < 0.001; three‐way anova). RelyX had significantly higher bond strengths compared with all other materials (P < 0.05; Tukey‐B). The apical region of the root canal had significantly higher bond strengths compared with the middle and coronal region (P < 0.05; Tukey‐B). After thermocycling for RelyX a significant increase in bond strengths was detected for the middle and apical region (P < 0.01; t‐test, Bonferroni factor 18).

Conclusions  Bond strengths were affected significantly by luting agent and root position. RelyX had higher bond strengths compared with other materials. The apical region of the canals was characterized by significantly higher bond strengths.
Cytokine‐induced prostaglandin E2 production and cyclooxygenase‐2 expression in dental pulp cells: downstream calcium signalling via activation of prostaglandin EP receptor
Authors: Chang M.‐C. , Chen Y.‐J. , Tai T.‐F. , Tai M.‐R. , Li M.‐Y. , Tsai Y.‐L. , Lan W.‐H. , Wang Y.‐L. , Jeng J.‐H.
Published: August 2006

Aim  To determine whether (i) proinflammatory cytokines stimulate prostaglandin E2 (PGE2) production and cyclooxygenase (COX) gene expression in dental pulp cells, and (ii) pulp cells that express different prostaglandin E2 receptor (EP) isoforms and their activation by PGE2 leads to downstream Ca2+ signalling.

Methodology  Cultured human dental pulp cells were exposed to interleukin (IL)‐1β and tumour necrotic factor‐alpha (TNF‐α). The expression of COX‐1 and COX‐2 was measured with reverse transcriptase‐polymerase chain reaction (RT‐PCR). The production of PGE2 was measured using an enzyme‐linked immunosorbent assay. Expression of prostaglandin EP receptor isoforms was studied by RT‐PCR, whereas fura‐2 fluorescence was used to measure calcium mobilization. The Kruskal–Wallis test and Wilcoxon sum rank test with Bonferroni correction were used for statistical analysis.

Results  Interleukin‐1β and TNF‐α stimulate PGE2 production of human dental pulp cells (P < 0.05). IL‐1β stimulated the COX‐2 but not COX‐1 mRNA expression. Pulp cells express mainly EP2, EP3 and EP1 receptors as analysed by RT‐PCR. PGE2 (0.25–2 μmol L−1) stimulated the Ca2+ mobilization as indicated by increase in fura‐2 fluorescence.

Conclusions  Interleukin‐1β and TNF‐α may stimulate PGE2 production in dental pulp cells. Activation of prostaglandin EP receptors in dental pulp cells by PGE2 may induce Ca2+ signalling to regulate cellular biological activity during inflammation.
Diagnostic value of computed tomography in re‐treatment of root fillings in maxillary molars
Authors: Huumonen S. , Kvist T. , Gröndahl K. , Molander A.
Published: August 2006

Aim  To compare the diagnostic information and radiation dose between intraoral radiography and computed tomography (CT) in re‐treatment decision making concerning root fillings in maxillary molars.

Methodology  Thirty‐nine root‐filled maxillary molars with suspected apical periodontitis were examined with two intraoral periapical radiographs and CT. Presence of periapical lesion/s per tooth and root were analysed for both techniques. In addition, in the CT images, the number of root canals, erosion, or perforation of cortical bone plates, and the distance between palatal root and cortical bone plates were evaluated. Radiation dose for CT was registered and calculated; and that of periapical radiographs used as reported previously (Ekestubbe et al. 2004).

Results  Periapical radiographs revealed periapical lesions in 33 teeth compared with 38 on CT images. A lesion of any root was detected more often with CT. The mesiobuccal root had two root canals in 30 teeth of which 27 of the MB2 canals were not filled, and 22 roots with an unfilled canal were associated a periapical lesion. Distances to palatal root, from the buccal and palatal cortex were measured in CT and varied between 5.0–12.0 mm and 0–4.0 mm, respectively. Based on the radiographic information, a variety of treatment alternatives were suggested. Mean effective dose of periapical radiographs was 0.02 mSv and that of CT 0.055 mSv.

Conclusions  Computed tomography may give important information in re‐treatment decision when considering root fillings in maxillary molars. The radiation dose should be considered individually.
Nerve Growth Factor Secretion in Cultured Enteric Glia Cells is Modulated by Proinflammatory Cytokines
Authors: Von Boyen G. B. T. , Steinkamp M. , Reinshagen M. , Schäfer K.‐H. , Adler G. , Kirsch J.
Published: August 2006

The enteric nervous system is composed of neurones and glial cells. These enteric glia cells (EGC) appear to be essential for the maintenance of gut homeostasis and mucosal integrity. Neurotrophin nerve growth factor (NGF) also plays an important role for the gut integrity by regulating sensory and inflammatory processes in the intestines. Here, we demonstrate EGCs as one source of NGF and show increased levels of NGF mRNA/protein and tropomyosin receptor kinase A (TrkA) mRNA in cultured EGCs upon stimulation with proinflammatory cytokines and lipopolysaccharides. NGF is continuously secreted from cultured EGCs and proinflammatory cytokines and lipopolysaccharides stimulate the secretion of this neurotrophin in a time‐ and dose‐ dependent manner, whereas interleukin‐4 had no effect on NGF expression. Furthermore, NGF secretion was sustained for more than 12 h after withdrawal of the proinflammatory cytokines, suggesting the involvement of transcriptional and/or translational processes. Thus, the release of proinflammatory cytokines can increase NGF secretion by EGCs and leads to a higher expression of TrkA in EGCs. NGF, in turn, can increase visceral sensitivity and, on the other hand, appears to improve gut inflammation. Therefore, NGF secreting EGCs may play a key role in modulating visceral sensitivity and might be involved in inflammatory processes of the gut.
Lack of Annexin 1 Results in an Increase in Corticotroph Number in Male but not Female Mice
Authors: Morris J. F. , Omer S. , Davies E. , Wang E. , John C. , Afzal T. , Wain S. , Buckingham J. C. , Flower R. J. , Christian H. C.
Published: August 2006

Annexin 1 (ANXA1) is a member of the annexin family of phospholipid‐ and calcium‐binding proteins with a well demonstrated role in early delayed (30 min to 3 h) inhibitory feedback of glucocorticoids in the pituitary. We have examined corticotrophs in wild‐type and ANXA1 knockout mice to determine the effects of lack of ANXA1 in male and female animals. Anterior pituitary tissue from ANXA1 wild‐type, heterozygote and null mice was fixed and examined (i) by confocal immunocytochemistry to determine the number of corticotrophs and (ii) by electron microscopy to examine the size, secretory granule population and secretory machinery of corticotrophs. No differences in these parameters were detected in female mice. In male ANXA1 null mice, there were approximately four‐fold more corticotrophs than in wild‐type animals. However, the corticotrophs in ANXA1 null mice were smaller and had reduced numbers of secretory granules (the reduction in granules paralleled the reduction in cell size). No differences in the numerical density of folliculo‐stellate, gonadotroph, lactotroph or somatotroph cells were detected in male ANXA1 null mice. Plasma corticosterone, adrenocorticotrophic hormone (ACTH) and pituitary pro‐opiomelanocortin mRNA were unchanged but pituitary ACTH content was increased in male ANXA1 null mice. Interleukin (IL)‐6 pituitary content was significantly elevated in male and reduced in female ANXA1 null mice compared to wild‐type. In conclusion, these data indicate that ANXA1 deficiency is associated with gender‐specific changes in corticotroph number and structure, via direct actions of ANXA1 and/or indirect changes in factors such as IL‐6.
Low density lipoprotein receptor transcripts correlates with liver hepatitis C virus RNA in patients with alcohol consumption
Authors: Carrière M. , Rosenberg A. R. , Conti F. , Chouzenoux S. , Terris B. , Sogni P. , Soubrane O. , Calmus Y. , Podevin P.
Published: August 2006

Summary.  Alcohol consumption has a major impact on the natural history of chronic hepatitis C virus (HCV) infection, although the underlying mechanisms are still debated. We designed a clinical study to evaluate the impact of alcohol abuse on both viral load and expression of low‐density lipoprotein receptor (LDLR) and CD81 expression. Thirty‐eight consecutive HCV‐infected patients were enrolled. Group 1 (n = 18), ≤10 g alcohol/day, group 2 (n = 8), ≤30 g alcohol/day, group 3 (n = 12), ≥30 g alcohol/day. Receptors expression was measured by flow cytometry analysis in peripheral blood mononuclear cells (PBMC) and by specific real‐time retrotranscription polymerase chain reaction (RT‐PCR) in the liver. Serum viral load was evaluated by quantification of both HCV genomic RNA and total core antigen. The hepatic viral load was assessed by real‐time RT‐PCR. Serum HCV‐RNA and total core antigen were significantly correlated, and were higher, albeit not significantly, in group 3 than in group 1. Alcohol consumption had no effect on expression of HCV putative receptors in PBMC, except for CD81, which was upregulated on monocytes in group 2. In the liver, viral load and levels of LDLR transcripts were significantly higher in group 3 than in group 1. Remarkably, a significant positive correlation was found between LDLR transcripts and HCV‐RNA (r2 = 0.83, P < 10−3). Finally, in vitro experiments suggested that the effect of ethanol on LDLR expression was indirectly mediated by both tumour necrosis factor‐α and interleukin‐1β. In conclusion, this study is the first to support a role for LDLR in the natural infection by HCV in man.
Differential patterns of morphological and molecular hybridization between Fraxinus excelsior L. and Fraxinus angustifolia Vahl (Oleaceae) in eastern and western France
Authors: FERNANDEZ‐MANJARRES J. F. , GERARD P. R. , DUFOUR J. , RAQUIN C. , FRASCARIA‐LACOSTE N.
Published: August 2006

We examined large‐scale patterns of morphology, genetic structure and ecological correlates of Fraxinus excelsior and the closely related species Fraxinus angustifolia in France, in order to determine the degree of hybridization between them. We sampled 24 populations in two putative hybrid zones (Loire and Saône), and five control populations of each species. We measured foliar characteristics of adult trees and used five nuclear microsatellites as molecular markers. Canonical discriminant analysis indicated that the two species differ in morphology, but that intermediate types are common in the Loire region but less frequent in the Saône region. Bayesian population assignment identified one F. angustifolia and two F. excelsior gene pools. Most Loire individuals clustered genetically with the F. angustifolia gene pool. In contrast, the Saône region presented individuals belonging mostly to F. excelsior pools, although the F. angustifolia type was frequent in certain populations. The lowest FST values were found between the Loire and F. angustifolia controls that also exhibited no significant isolation by distance. The proportion of the F. angustifolia gene pool in each locality was negatively correlated with winter temperatures, suggesting that a cold climate may be limiting. Hybridization is probably favoured by the intermediate climatic conditions in the Loire region that allow both species to occur, but is somewhat hampered by the harsher winters in the Saône area where morphological introgression has apparently not yet occurred.
Comparative phylogeography of the Veronica alpina complex in Europe and North America
Authors: ALBACH DIRK C. , SCHÖNSWETTER PETER , TRIBSCH ANDREAS
Published: August 2006

The Veronica alpina complex comprises eight species of alpine habitats over a wide range of mountain systems in the Northern Hemisphere. The occurrence of sympatric species in the European and North American mountain systems allowed us not only to investigate the effect of the ice ages on intraspecific phylogeographical patterns and genetic diversity in different continents of the Northern Hemisphere, but also to compare these patterns in closely related species. Plastid DNA trnL‐F sequences and AFLP (amplified fragment length polymorphism) fingerprints were used to infer the phylogenetic history of the group and phylogeographical patterns within species. Hybrid origin of tetraploid eastern North American V. wormskjoldii from western North American V. nutans (= V. wormskjoldii s.l.) and Eurasian V. alpina is suggested. A number of phylogeographical groups have been found both in V. alpina from Europe and in V. nutans from western North America. Phylogeographical substructuring in the Alps is inferred for V. alpina but not for V. bellidioides, which is moreover characterized by an overall very low genetic diversity. Western North American V. cusickii is much more genetically diverse than its sympatric relative, V. nutans, an effect that is likely due to differences in the breeding system. Populations of V. nutans are differentiated into three groups, those from the Cascades and from the southern and the northern Rocky Mountains. Genetic diversity seems to be higher in the North American V. nutans than in the morphologically and ecologically similar European V. alpina. A possible scenario to explain this pattern is suggested.
Incomplete cryptic speciation between intertidal and subtidal morphs of Acrocnida brachiata (Echinodermata: Ophiuroidea) in the Northeast Atlantic
Authors: MUTHS D. , DAVOULT D. , GENTIL F. , JOLLIVET D.
Published: August 2006

The brittle‐star Acrocnida brachiata (Montagu) lives in sandy‐bottom habitat of both intertidal and subtidal zones along the coasts of the northwestern Europe. An allozyme frequency‐based survey (five enzyme loci) was combined with a mitochondrial (mt) COI haplotype analysis (598‐bp sequences) on 17 populations to trace back past colonization pathways from the actual population structure of the species. Both genetic markers display a sharp genetic break between intertidal (clade I) and subtidal populations (clade S). This break corresponds to an allele frequency inversion at three enzyme loci (Hk, Pgm and Pgi) and a deep divergence of about 20% in mtCOI sequences between most of the intertidal populations and other samples. The geographic distribution of clade I seems to be more restricted than clade S as it is absent from the intertidal of the eastern English Channel and North Sea and may be replaced by clade S in south Brittany. Applying previously published rates of mutation, divergence between the two clades is estimated to pre‐date 5 million years ago and may be due to allopatric speciation processes at the Mio–Pliocene transition. The occurrence of putative hybrids in a few localities, however, suggests incomplete cryptic speciation with secondary contact zones. The relative importance of colonization history vs. habitat specialization are discussed in the light of neutral evolution as tested from mtCOI gene sequences. While differential selection seems to have contributed little to the separation of the lineages, it may have played a role in the emergence of adaptive polymorphisms in the hybrid zone. Furthermore, congruent spatial patterns of differentiation were observed in both clades suggesting a recent increase in population size. These findings are in agreement with a recent expansion of the populations during or after the formation of the English Channel, from a southern refuge for the subtidal clade whereas the intertidal clade may have persisted further north. As previously suspected for a species with a very short pelagic larval phase, contemporary gene flow between distant or adjacent populations appears to be extremely reduced or even absent.