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Significant Response (significant + response)
Selected AbstractsDistant nodal metastases from intrathoracic esophageal squamous cell carcinoma: Characteristics of long-term survivors after chemoradiotherapyJOURNAL OF SURGICAL ONCOLOGY, Issue 2 2010Yin-Kai Chao MD Abstract Background Non-regional lymph node metastasis in intrathoracic esophageal cancer is classified as M1 lesion with poor prognosis following surgery alone. We studied the controversial question of whether chemoradiotherapy (CRT) improves survival of these patients. Methods A cohort of patients with clinically overt nodal M1 disease, which could be encompassed by a tolerable radiation therapy port, was selected from the database of the Chang Gung Memorial Hospital. Results From 1994 to 2005, 54 nodal stage IV intrathoracic esophageal squamous cell carcinoma (SCC) patients received neoadjuvant CRT. Significant response occurred in 24 patients. Scheduled esophagectomy was performed in 26 patients. The 3-year overall survival (OS) and disease-free survival (DFS) for the whole group were 27% (median: 14.2 months) and 22% (median: 14.7 months), respectively. Multivariate analysis identified pretherapy lymph nodes classified as M1a and R0 resection after CRT as independent favorable prognosticators. Median survival reached 36.9 months in the pretherapy M1a subgroup as opposed to 12.5 months in the M1b subgroup (3-year-DFS: 40% vs. 10%, P,=,0.0117). Scheduled surgery after CRT benefits only after R0 resection (3-year-DFS: 36%, median survival: 45 months). The group with incomplete resection had a high surgical risk and dismal survival compared to the non-surgery group (3-year-DFS: 0% vs. 9%, 9.5 vs. 10.5 months). Conclusions Pretherapy M1a disease had a significantly better survival than nodal M1b disease after CRT in SCC. Aggressive surgical treatment after CRT is reserved for cases when complete resection is anticipated. J. Surg. Oncol. 2010;102:158,162. © 2010 Wiley-Liss, Inc. [source] Nucleotide-mediated calcium signaling in rat cortical astrocytes: Role of P2X and P2Y receptorsGLIA, Issue 3 2003Marta Fumagalli Abstract ATP is the dominant messenger for astrocyte-to-astrocyte calcium-mediated communication. Definition of the exact ATP/P2 receptors in astrocytes and of their coupling to intracellular calcium ([Ca2+]i) has important implications for brain physiology and pathology. We show that, with the only exception of the P2X6 receptor, primary rat cortical astrocytes express all cloned ligand-gated P2X (i.e., P2X1,5 and P2X7) and G-protein-coupled P2Y receptors (i.e., P2Y1, P2Y2, P2Y4, P2Y6, and P2Y12). These cells also express the P2Y-like UDP-glucose receptor, which has been recently recognized as the P2Y14 receptor. Single-cell image analysis showed that only some of these receptors are coupled to [Ca2+]i. While ATP induced rapid and transient [Ca2+]i increases (counteracted by the P2 antagonists suramin, pyridoxal-phosphate-6-azophenyl-2,-4,-disulfonic acid and oxidized ATP), the P2X1/P2X3 agonist ,,meATP produced no changes. Conversely, the P2X7 agonist BzATP markedly increased [Ca2+]i; the presence and function of the P2X7 receptor was also confirmed by the formation of the P2X7 pore. ADP and 2meSADP also produced [Ca2+]i increases antagonized by the P2Y1 antagonist MRS2179. Some cells also responded to UTP but not to UDP. Significant responses to sugar-nucleotides were also detected, which represents the first functional response reported for the putative P2Y14 receptor in a native system. Based on agonist preference of known P2 receptors, we conclude that, in rat astrocytes, ATP-induced calcium rises are at least mediated by P2X7 and P2Y1 receptors; additional receptors (i.e., P2X2, P2X4, P2X5, P2Y2, P2Y4, and P2Y14) may also contribute. © 2003 Wiley-Liss, Inc. [source] Climate change effects on upland stream macroinvertebrates over a 25-year periodGLOBAL CHANGE BIOLOGY, Issue 5 2007ISABELLE DURANCE Abstract Climate change effects on some ecosystems are still poorly known, particularly where they interact with other climatic phenomena or stressors. We used data spanning 25 years (1981,2005) from temperate headwaters at Llyn Brianne (UK) to test three hypotheses: (1) stream macroinvertebrates vary with winter climate; (2) ecological effects attributable to directional climate change and the North Atlantic Oscillation (NAO) are distinguishable and (3) climatic effects on macroinvertebrates depend on whether streams are impacted by acidification. Positive (i.e. warmer, wetter) NAO phases were accompanied by reduced interannual stability (=similarity) in macroinvertebrate assemblage in all streams, but associated variations in composition occurred only in acid moorland. The NAO and directional climate change together explained 70% of interannual variation in temperature, but forest and moorland streams warmed respectively by 1.4 and 1.7°C (P<0.001) between 1981 and 2005 after accounting for NAO effects. Significant responses among macroinvertebrates were confined to circumneutral streams, where future thermal projections (+1, +2, +3°C) suggested considerable change. Spring macroinvertebrate abundance might decline by 21% for every 1°C rise. Although many core species could persist if temperature gain reached 3°C, 4,10 mostly scarce taxa (5,12% of the species pool) would risk local extinction. Temperature increase in Wales approaches this magnitude by the 2050s under the Hadley HadCM3 scenarios. These results support all three hypotheses and illustrate how headwater stream ecosystems are sensitive to climate change. Altered composition and abundance could affect conservation and ecological function, with the NAO compounding climate change effects during positive phases. We suggest that acidification, in impacted streams, overrides climatic effects on macroinvertebrates by simplifying assemblages and reducing richness. Climatic processes might, nevertheless, exacerbate acidification or offset biological recovery. [source] Adapting wheat cultivars to resource conserving farming practices and human nutritional needsANNALS OF APPLIED BIOLOGY, Issue 4 2005R M TRETHOWAN Summary As farmers increasingly adopt resource conserving farming practices, there is a need for wheat cultivars that better adapt to the changing environment and the nutritional needs of people, particularly those living in developing countries. Improved adaptation to zero and minimum tillage, better water use efficiency, improved root health, durable resistance to foliar diseases and enhanced nutritional value of the grain are key selection criteria for plant breeders. Significant responses to selection for these constraints have been achieved at the International Maize and Wheat Improvement Center (CIMMYT), by selecting segregating populations and advanced lines in carefully managed tillage, moisture deficit and heat stressed environments, that correlate with key spring wheat growing environments globally. Root health has been improved through a combination of marker assisted selection and disease bioassays, and the nutritional value of wheat grain has been enhanced using genetic variation for high Fe and Zn grain content found among tetraploid wheat ancestral species. [source] Increase of atmospheric CO2 promotes phytoplankton productivityECOLOGY LETTERS, Issue 6 2004Peter Schippers Abstract It is usually thought that unlike terrestrial plants, phytoplankton will not show a significant response to an increase of atmospheric CO2. Here we suggest that this view may be biased by a neglect of the effects of carbon (C) assimilation on the pH and the dissociation of the C species. We show that under eutrophic conditions, productivity may double as a result of doubling of the atmospheric CO2 concentration. Although in practice productivity increase will usually be less, we still predict a productivity increase of up to 40% in marine species with a low affinity for bicarbonate. In eutrophic freshwater systems doubling of atmospheric CO2 may result in an increase of the productivity of more than 50%. Freshwaters with low alkalinity appeared to be very sensitive to atmospheric CO2 elevation. Our results suggest that the aquatic C sink may increase more than expected, and that nuisance phytoplankton blooms may be aggravated at elevated atmospheric CO2 concentrations. [source] Dispersal and influences on movement for Anoplophora glabripennis calculated from individual mark-recaptureENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 2 2005J.S. Bancroft Abstract We conducted an individual mark-release-recapture experiment on the beetle, Anoplophora glabripennis Motchulsky (Coleoptera: Cerambycidae). This invasive beetle has been introduced from Asia to Europe and North America and poses a serious threat to several important species of tree. Eradication efforts may benefit from knowledge of dispersal behaviour. Trees were cut and held to determine emergence rate of A. glabripennis. Unique marks were painted onto 912 beetles released into a group of 165 trees in Gansu, China. Data on subsequent sightings of beetles were used in a truncated diffusion model to calculate flight distances. Characteristics of the trees and climatic information were used in statistical tests for influence on movement. A total of 2245 sightings of beetles were observed and 29% of marked beetles were resighted. The scanning technique using binoculars was 90% effective in finding beetles and provided 81% accuracy for determining the sex of the beetles. Experimental manipulation of density quantified how A. glabripennis congregated on unoccupied trees and were repulsed from crowded hosts. The seasonal emergence rate of adults declined exponentially from July 20 to August 5. The results suggested A. glabripennis fly to nearby host trees at a rate of 34% per day. Median flight distance was estimated at 20 m per day. Statistical analysis with a generalized linear model tested the beetle's propensity to leave a tree and distance of flight. Generally, beetle movement showed a significant response to beetle density, weather conditions, beetle size, and tree size, in that order. The techniques developed here improve on previous recapture techniques to quantify dispersal and can be useful for analysing populations of other organisms. [source] Neural correlates of binaural masking level difference in the inferior colliculus of the barn owl (Tyto alba)EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 4 2010Ali Asadollahi Abstract Humans and animals are able to detect signals in noisy environments. Detection improves when the noise and the signal have different interaural phase relationships. The resulting improvement in detection threshold is called the binaural masking level difference. We investigated neural mechanisms underlying the release from masking in the inferior colliculus of barn owls in low-frequency and high-frequency neurons. A tone (signal) was presented either with the same interaural time difference as the noise (masker) or at a 180° phase shift as compared with the interaural time difference of the noise. The changes in firing rates induced by the addition of a signal of increasing level while masker level was kept constant was well predicted by the relative responses to the masker and signal alone. In many cases, the response at the highest signal levels was dominated by the response to the signal alone, in spite of a significant response to the masker at low signal levels, suggesting the presence of occlusion. Detection thresholds and binaural masking level differences were widely distributed. The amount of release from masking increased with increasing masker level. Narrowly tuned neurons in the central nucleus of the inferior colliculus had detection thresholds that were lower than or similar to those of broadly tuned neurons in the external nucleus of the inferior colliculus. Broadly tuned neurons exhibited higher masking level differences than narrowband neurons. These data suggest that detection has different spectral requirements from localization. [source] Recovery of two independent sweet taste systems during regeneration of the mouse chorda tympani nerve after nerve crushEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 6 2007Keiko Yasumatsu Abstract In rodents, section of the taste nerve results in degeneration of the taste buds. Following regeneration of the cut taste nerve, however, the taste buds reappear. This phenomenon can be used to study the functional reformation of the peripheral neural system responsible for sweet taste. In this study we examined the recovery of sweet responses by the chorda tympani (CT) nerve after nerve crush as well as inhibition of these responses by gurmarin (Gur), a sweet response inhibitor. After about 2 weeks of CT nerve regeneration, no significant response to any taste stimuli could be observed. At 3 weeks, responses to sweet stimuli reappeared but were not significantly inhibited by Gur. At 4 weeks, Gur inhibition of sweet responses reached statistically significant levels. Thus, the Gur-sensitive (GS) component of the sweet response reappeared about 1 week later than the Gur-insensitive (GI) component. Moreover, single CT fibers responsive to sucrose could be classified into distinct GS and GI groups at 4 weeks. After 5 weeks or more, responses to sweet compounds before and after treatment with Gur became indistinguishable from responses in the intact group. During regeneration, the GS and GI components of the sucrose response could be distinguished based on their concentration-dependent responses to sucrose. These results suggest that mice have two different sweet-reception systems, distinguishable by their sensitivity to Gur (the GS and GI systems). These two sweet-reception systems may be reconstituted independently during regeneration of the mouse CT nerve. [source] Ecological responses to nutrients in streams and rivers of the Colorado mountains and foothillsFRESHWATER BIOLOGY, Issue 9 2010WILLIAM M. LEWIS Summary 1. Abundance and composition of periphyton and benthic macroinvertebrates were treated as potential nutrient response variables for 74 streams in montane Colorado. The streams ranged from unenriched to mildly enriched with nutrients (N, P). 2. The study showed no meaningful relationship between periphyton biomass accumulation and concentrations of total or dissolved forms of nitrogen or phosphorus. Nutrient concentrations were also unrelated to periphyton and macroinvertebrate richness, diversity and community composition. Macroinvertebrate communities did, however, show a strong positive relationship to periphyton abundance. 3. A positive response of periphyton biomass to increasing nutrient concentrations has been well documented over large ranges of nutrient concentrations. Our study suggests that the nutrient response is suppressed by other controlling factors on the lower limb of the nutrient response curve (i.e. at low nutrient concentrations); a quantitatively significant response occurs only in excess of a threshold beyond which nutrients become dominant over other controlling factors. This interpretation of the results is consistent with published meta-analyses showing lack of nutrient response for a high proportion of experimentally enriched periphyton communities, and division of responses between N and P for communities that do show growth in response to enrichment. 4. Grazing probably is not the key controlling variable for periphyton in Colorado mountain streams, given that the highest chlorophyll concentrations are associated with the highest abundances of macroinvertebrates. Modelling indicates that the initial amount of periphyton biomass at the start of the growing season, in conjunction with elevation-related length of the growing season and water temperature, explains most of the variation in periphyton accumulation among these streams, but there is a yet unexplained suppression of periphyton growth rates across all elevations. [source] Assessment of European streams with diatoms, macrophytes, macroinvertebrates and fish: a comparative metric-based analysis of organism response to stressFRESHWATER BIOLOGY, Issue 9 2006DANIEL HERING Summary 1. Periphytic diatoms, macrophytes, benthic macroinvertebrates and fish were sampled with standard methods in 185 streams in nine European countries to compare their response to degradation. Streams were classified into two main stream type groups (i.e. lowland, mountain streams); in addition, the lowland streams were grouped into four more specific stream types. 2. Principal components analysis with altogether 43 environmental parameters was used to construct complex stressor gradients for physical,chemical, hydromorphological and land use data. About 30 metrics were calculated for each sample and organism group. Metric responses to different stress types were analysed by Spearman Rank Correlation. 3. All four organism groups showed significant response to eutrophication/organic pollution gradients. Generally, diatom metrics were most strongly correlated to eutrophication gradients (85% and 89% of the diatom metrics tested correlated significantly in mountain and lowland streams, respectively), followed by invertebrate metrics (91% and 59%). 4. Responses of the four organism groups to other gradients were less strong; all organism groups responded to varying degrees to land use changes, hydromorphological degradation on the microhabitat scale and general degradation gradients, while the response to hydromorphological gradients on the reach scale was mainly limited to benthic macroinvertebrates (50% and 44% of the metrics tested correlated significantly in mountain and lowland streams, respectively) and fish (29% and 47%). 5. Fish and macrophyte metrics generally showed a poor response to degradation gradients in mountain streams and a strong response in lowland streams. 6. General recommendations on European bioassessment of streams were derived from the results. [source] Bacteria and PAMPs activate nuclear factor ,B and Gro production in a subset of olfactory ensheathing cells and astrocytes but not in Schwann cellsGLIA, Issue 9 2007Adele J. Vincent Abstract The primary olfactory nerves provide uninterrupted conduits for neurotropic pathogens to access the brain from the nasal cavity, yet infection via this route is uncommon. It is conceivable that olfactory ensheathing cells (OECs), which envelope the olfactory nerves along their entire length, provide a degree of immunological protection against such infections. We hypothesized that cultured OECs would be able to mount a biologically significant response to bacteria and pathogen-associated molecular patterns (PAMPs). The response of OECs to Escherichia coli (E. coli) and various PAMPs was compared to that of Schwann cells (SCs), astrocytes (ACs), and microglia (MG). A subset of OECs displayed nuclear localization of nuclear factor ,B), an inflammatory transcription factor, after treatment with E. coli (20% ± 5%), lipopolysacchride (33% ± 9%), and Poly I:C (25% ± 5%), but not with peptidoglycan or CpG oligonucleotides. ACs displayed a similar level of activation to these treatments, and in addition responded to peptidoglycan. The activation of OECs and ACs was enhanced by coculture with MG (56% ± 16% and 85% ± 13%, respectively). In contrast, SCs did not respond to any treatment or to costimulation by MG. Immunostaining for the chemokine Gro demonstrated a functional response that was consistent with NF,B activation. OECs expressed mRNA for Toll-like receptors (TLRs) 2 and 4, but only TLR4 protein was detected by Western blotting and immunohistochemistry. The results demonstrate that OECs possess the cellular machinery that permits them to respond to certain bacterial ligands, and may have an innate immune function in protecting the CNS against infection. © 2007 Wiley-Liss, Inc. [source] Interferon alpha receptors are important for antiproliferative effect of interferon-, against human hepatocellular carcinoma cellsHEPATOLOGY RESEARCH, Issue 1 2007Bazarragchaa Damdinsuren Aim:, Interferon (IFN)-, is a promising drug for the prevention and treatment of hepatocellular carcinoma (HCC). We reported that responders to IFN-,/5-fluorouracil combination therapy expressed higher IFN alpha receptor (IFNAR)2 in tumor. Herein we studied involvement of IFNARs in response to IFN-, in HCC cells. Methods:, IFN-, sensitivity and expression of IFNARs were studied in six HCC cell lines (HuH7, PLC/PRF/5, HLE, HLF, HepG2, Hep3B) using growth-inhibitory and RT-PCR, Western blot assays. Short interfering RNAs (SiRNAs) against IFNAR1 and 2 were used to analyze the role of the IFNARs in IFN-,'s effect and signal transduction. Results:, The expressions of IFNAR1 and 2c mRNAs were higher in PLC/PRF/5 cells than those in other cell lines, and PLC/PRF/5 cells expressed abundant IFNAR2c on their cell membrane. When we examined the sensitivity of the HCC cell lines to the growth-inhibitory effect of IFN-,, PLC/PRF/5 exhibited a significant response, while the other cells were much more resistant. Knockdown of either IFNAR1 or 2 using siRNAs suppressed the IFN-,'s signal transduction (2.5-fold), and decreased the growth-inhibitory effect (down by 69.9% and 67.3%). Conclusion:, The results suggest that the expression of IFNAR1 and IFNAR2c independently are important for the antiproliferative effect of IFN-, in HCC cells. [source] The effects of edge, fragment size and degree of isolation on avian species richness in highly fragmented forest in West AfricaIBIS, Issue 2 2007S. MANU Almost nothing is known of the effects of forest fragmentation on bird diversity within the heavily degraded and fragmented forest remnants in West Africa. We examined the effects of edge, fragment size and isolation on bird species richness in southwestern Nigeria where forest fragmentation is pronounced. In total, 122 km of line transects were used to survey birds and vegetation within 45 forest patches between January 2000 and March 2002: 197 species were recorded. Avian species number and total counts in forest patches were unrelated to fragment area (within the observed range of 14,445 ha), but were negatively influenced by degree of isolation and increasing distance from the edge. As the total area of forested land within 15 km of a patch fell from 4 to 0%, so 21% of species were lost. In total, six and zero species (of 154 recorded more than once) were consistently recorded in the larger and smaller forest fragments, respectively, and four and two bird species were consistently recorded in unisolated and isolated forest fragments, respectively, suggesting that the addition of ,edge' species did not compensate for loss of species sensitive to fragmentation. Diversity index was not affected by either fragment area or degree of isolation, but decreased with distance from the edge. When individual species counts were considered, 68% of species (n = 62) showed no significant effect of distance to edge. Of those 20 species which showed an effect, 12 were less common close to the edge. Most species (65%) did not respond significantly to increasing isolation but of those 22 species that did, 20 were less common in more isolated fragments. Ninety-seven per cent of species showed no significant response to area. As avian diversity and species composition, but not species number, were apparently insensitive to forest fragmentation, our findings suggest that fragmentation reduces the probability of occurrence of a wide range of West African bird species, rather than a subset of fragmentation-sensitive species. The greater apparent sensitivity of present-day West African forest bird communities to fragmentation rather than patch size might reflect previous extinctions of area-sensitive species. Minimizing further forest fragmentation might be the most effective means of conserving avian diversity in current West African landscapes where most remaining forest patches are small (i.e. < 500 ha). [source] Chemical surface passivation of 3C-SiC nanocrystals: A first-principle studyINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 13 2010A. Trejo Abstract The effect of the chemical surface passivation, with hydrogen atoms, on the energy band gap of porous cubic silicon carbide (PSiC) was investigated. The pores are modeled by means of the supercell technique, in which columns of Si and/or C atoms are removed along the [001] direction. Within this supercell model, morphology effects can be analyzed in detail. The electronic band structure is performed using the density functional theory based on the generalized gradient approximation. Two types of pores are studied: C-rich and Si-rich pores surface. The enlargement of energy band gap is greater in the C-rich than Si-rich pores surface. This supercell model emphasizes the interconnection between 3C-SiC nanocrystals, delocalizing the electronic states. However, the results show a clear quantum confinement signature, which is contrasted with that of nanowire systems. The calculation shows a significant response to changes in surface passivation with hydrogen. The chemical tuning of the band gap opens the possibility plenty applications in nanotechnology. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem 110:2455,2461, 2010 [source] Factors affecting the response of Ceutorhynchus assimilis Payk. (Col., Curculionidae) males to conspecific odourJOURNAL OF APPLIED ENTOMOLOGY, Issue 8 2001F. Nazzi The effect of post-emergence feeding on the response of Ceutorhynchus assimilis males to conspecific odour was studied using both laboratory-overwintered and field-collected weevils. The response of males to females at different times in the season was also investigated using field-collected weevils. Males did not respond to the odour of virgin females that were newly emerged from diapause. However, they showed a significant response to the odour of overwintered virgin females that had spent some days on flowering rape. The response of males to females appeared to decline as the season progressed. [source] Shifts in the ecological behaviour of plant species between two distant regions: evidence from the base richness gradient in miresJOURNAL OF BIOGEOGRAPHY, Issue 2 2008Petra Hájková Abstract Aim, Water pH and conductivity are known to be major environmental factors controlling the species composition of nutrient-poor wetlands. Based on the analysis of two large data sets of species co-occurrence, sampled along the entire pH/calcium gradient, we explored whether species exhibit similar or different ecological behaviour in the two regions. Location, West Carpathians (central Europe) and Bulgaria (south-eastern Europe), situated 800 km apart. Bulgaria represents a range margin for many mire species. Methods, The probability of occurrence of the 41 most common species along the pH and conductivity gradients was assessed using logistic regression fitted by means of generalized additive models. The species optimum and amplitude were determined. To check the possible effect of competitive release, we estimated where the potential maximum number of species (maximum overlap in realized niches) occurs along the base richness gradient. Results, Most of the 41 frequently occurring species showed a significant response to water pH and ln-transformed conductivity (approximating total mineral richness) in both regions. Eight species showed a shift in pH optimum greater than one unit, while 12 species showed the same or a larger shift along the conductivity gradient. Nearly all these striking shifts were connected to an extension of species tolerance towards mineral-poor acid habitats in Bulgaria, which causes links between species and measured factors to be conspicuously weaker in Bulgaria than in the West Carpathians. Regarding ecological amplitude, 24 species exhibited a wider tolerance to water conductivity in the West Carpathians, whereas 17 species exhibited a wider tolerance in Bulgaria. Main conclusions, A distinctive variation in the realized niche was observed in a large portion of the species examined. Niche shifts between local populations of the same species were similar to those of closely related vicariant species. Ecotypic adaptation within species is a possible explanation for this pattern. Other possible explanations (competitive release, specific habitat conditions, compensation for climate) seem to be less justified. The local populations of rich-fen species may have adapted to mineral-poor acid conditions in the high crystalline mountains of Bulgaria during dry periods of pleniglacials. Nomenclature,Marhold & Hindák (1998); for Balkan elements not included in this source, Andreev et al. (1992). [source] Intensity and Importance of Competition for a Grass (Festuca rubra) and a Legume (Trifolium pratense) Vary with Environmental ChangesJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 12 2008Junyan Zhang Abstract How plant competition varies across environmental gradients has been a long debate among ecologists. We conducted a growth chamber experiment to determine the intensity and importance of competition for plants grown in changed environmental conditions. Festuca rubra and Trifolium pratense were grown in monoculture and in two- and/or three-species mixtures under three environmental treatments. The measured competitive variations in terms of growth (height and biomass) were species-dependent. Competition intensity for Festuca increased with decreased productivity, whilst competition importance displayed a humpback response. However, significant response was detected in neither competition intensity nor importance for Trifolium. Intensity and importance of competition followed different response patterns, suggesting that they may not be correlated along an environmental gradient. The biological and physiological variables of plants play an important role to determine the interspecific competition associated with competition intensity and importance. However, the competitive feature can be modified by multiple environmental changes which may increase or hinder how competitive a plant is. [source] BENTHIC AND PLANKTONIC ALGAL COMMUNITIES IN A HIGH ARCTIC LAKE: PIGMENT STRUCTURE AND CONTRASTING RESPONSES TO NUTRIENT ENRICHMENT,JOURNAL OF PHYCOLOGY, Issue 6 2005Sylvia Bonilla We investigated the fine pigment structure and composition of phytoplankton and benthic cyanobacterial mats in Ward Hunt Lake at the northern limit of High Arctic Canada and the responses of these two communities to in situ nutrient enrichment. The HPLC analyses showed that more than 98% of the total pigment stocks occurred in the benthos. The phytoplankton contained Chrysophyceae, low concentrations of other protists and Cyanobacteria (notably picocyanobacteria), and the accessory pigments chl c2, fucoxanthin, diadinoxanthin, violaxanthin, and zeaxanthin. The benthic community contained the accessory pigments chl b, chl c2, and a set of carotenoids dominated by glycosidic xanthophylls, characteristic of filamentous cyanobacteria. The black surface layer of the mats was rich in the UV-screening compounds scytonemin, red scytonemin-like, and mycosporine-like amino acids, and the blue-green basal stratum contained high concentrations of light-harvesting pigments. In a first bioassay of the benthic mats, there was no significant photosynthetic or growth response to inorganic carbon or full nutrient enrichment over 15 days. This bioassay was repeated with increased replication and HPLC analysis in a subsequent season, and the results confirmed the lack of significant response to added nutrients. In contrast, the phytoplankton in samples from the overlying water column responded strongly to enrichment, and chl a biomass increased by a factor of 19.2 over 2 weeks. These results underscore the divergent ecophysiology of benthic versus planktonic communities in extreme latitudes and show that cold lake ecosystems can be dominated by benthic phototrophs that are nutrient sufficient despite their ultraoligotrophic overlying waters. [source] Ultrasound-guided photodynamic therapy for deep seated pathologies: prospective studyLASERS IN SURGERY AND MEDICINE, Issue 9 2009Waseem Jerjes MSc (OMFS) Abstract Introduction Interstitial photodynamic therapy remains an attractive remedial option in minimally invasive surgery. Our aim in this prospective study was to evaluate the outcome following ultrasound-guided iPDT of deep-seated pathologies. Patients' reports on quality of life with clinical and radiological evaluation were the main end point parameters used to assess the outcome. Materials and Methods Sixty-eight patients were referred to the UCLH Head and Neck Centre for treatment of various deep-seated pathologies involving the head and neck region, upper and lower limbs. All patients underwent interstitial photodynamic therapy under general anaesthesia, using 0.15,mg/kg mTHPC as the photosensitising agent. Following treatment, patients were followed-up for a mean of 7 months. Results All three patients who presented with visual problems reported improvement after treatment. Also, 14/17 patients reported improvement of breathing. Improvement of swallowing was reported by 25/30 patients; while speaking improvement was evident in 16/22 patients and 33/40 reported reduction in the disfigurement caused by their pathology. All five patients with impeded limb function reported some degree of improvement. Clinical assessment showed that half of the patients had ,good response' to the treatment and a third reported ,moderate response' with two patients being free of disease. Radiological assessment comparing imaging 6-week post-PDT to the baseline showed stable pathology with no change in size in 13 patients, minimal response in 18 patients, moderate response in 23 patients and significant response in 11 patients. Conclusion This study on 68 patients with deep-seated pathologies undergoing interstitial photodynamic therapy provided evidence that PDT can be the fourth modality in the management of tissue disease. Lasers Surg. Med. 41:612,621, 2009. © 2009 Wiley-Liss, Inc. [source] The role of the interdomain B linker in the activation of the XylR protein of Pseudomonas putidaMOLECULAR MICROBIOLOGY, Issue 2 2000Junkal Garmendia In the presence of toluene and other structural analogues, the enhancer binding protein XylR activates the ,54 promoter Pu of the TOL (toluene degradation) plasmid pWW0 of Pseudomonas putida. Introduction of amino acid changes Val-219Asp and Ala-220Pro, which enter a proline kink at the interdomain region (B linker) between the A (signal reception) module and the central portion of XylR, originated a protein with unforeseen properties. These included a minor ability to activate Pu in the absence of aromatic effectors, a much higher responsiveness to m- xylene and a significant response to a large collection of aromatic inducers. Such changes could not be attributed to variations in XylR expression levels or to the fortuitous creation of a novel promoter, but to a genuine change in the properties of the activator. Structural predictions suggested that the mutation entirely disrupted an otherwise probable coiled-coil structure. A second directed mutant within the same region consisting of a major replacement of amino acids A220,N221 by the peptide HHHR produced an even more exacerbated phenotype. These data support a model in which the linker B region influences the effector profile by modifying at a distance the operative shape of the effector pocket and fixing the protein in an intermediate step of the activation process. [source] Management of refractory urinary urge incontinence following urogynecological surgery with sacral neuromodulation,,NEUROUROLOGY AND URODYNAMICS, Issue 1 2007Jonathan S. Starkman Abstract Aims We sought to explore our patient outcomes utilizing sacral neuromodulation in the management of refractory urinary urge incontinence following urogynecological surgical procedures. Methods A total of 25 women with urinary urge incontinence following urogynecological surgery were selected for SNS therapy and retrospectively analyzed. All patients completed a comprehensive urological evaluation. Clinical data was recorded to determine outcomes and identify parameters that would be predictive of response to neuromodulation. Outcomes were determined via subjective patient questionnaire and graded as follows: significant response (,80% improvement), moderate response (,50% and <80% improvement), and poor response (<50% response). Results Nineteen patients had a previous pubovaginal sling (10 with concomitant pelvic prolapse repair), 3 a previous retropubic suspension, and 3 a transperitoneal vesicovaginal fistula repair. Urethrolysis was performed in 4 patients to alleviate bladder outlet obstruction prior to sacral neuromodulation. Mean patient age was 59.8 years and length of follow-up was 7.2 months. Twenty-two women (88%) had the IPG placed during a Stage 2 procedure. Twenty patients maintained at least a 50% improvement in clinical symptoms at last follow-up and 6 patients were continent. Overall, the number of pads/day improved from 4.2 to 1.1 (P,<,0.001). There were no significant differences in response to neuromodulation based upon age, duration of symptoms, type of surgery, or urodynamic parameters. Conclusion Sacral neuromodulation appears to be an effective therapy in patients with refractory urge incontinence following urogynecological surgery. Larger prospective studies with longer follow-up are needed to assess the durability of this therapeutic modality. Neurourol. Urodynam. © 2006 Wiley-Liss, Inc. [source] The use of higher dose clofarabine in adults with relapsed acute lymphoblastic leukemia,,§AMERICAN JOURNAL OF HEMATOLOGY, Issue 4 2009Bradley A. McGregor The standard dose of clofarabine is 52 mg/m2 for pediatrics and 40 mg/m2 in adults. Clofarabine dosed at 52 mg/m2 was used in adult patients with refractory ALL to maximize response before allo-HSCT. All patients had a significant response to therapy. Published pharmacokinetic analysis revealed no difference in peak plasma or intracellular concentrations at clofarabine dosed above 40 mg/m2, yet inhibition of replication in leukemia cells was only sustained over 24 hr at 55 mg/m2. Despite this, there have been no reports of high dose clofarabine used in this setting. Our experience implies that there may be a niche role for clofarabine in reducing disease burden before allo-HSCT for adults with relapsed ALL. Am. J. Hematol., 2009. Published 2009 Wiley-Liss, Inc. [source] Effects of single-dose fluticasone on exercise-induced asthma in asthmatic children: A pilot study,PEDIATRIC PULMONOLOGY, Issue 2 2001B.J. Thio MD Abstract A single high dose of inhaled corticosteroid (ICS) can increase airway caliber in children with asthma attacks and laryngitis subglottica. Presumably the effect is due to the vasoconstrictive and antiedematous properties of topical steroids. Enlarged vessels have been suggested to play a role in the pathophysiology of exercise-induced bronchial obstruction (EIB). To investigate this, we evaluated the effect of a single high dose of fluticasone propionate (FP) on EIB in asthmatic children. Nine children aged 8,16 years with mild to moderate asthma were included. All children had a history of EIB, which was confirmed by an exercise test. None was taking ICS maintenance therapy. The children inhaled either a single dose of 1 mg FP or placebo on 2 separate days within 7,14 days. After inhalation, airway caliber (FEV1) was assessed for 4 hr before exercise. Then an exercise challenge was performed on a treadmill to assess EIB (% fall FEV1). A significant increase in FEV1 was observed 1 hr after inhalation of FP compared to placebo. Response to exercise was expressed as maximal % fall in FEV1 from baseline (% fall) and as area under the curve (AUC) of the 30-min time/response curve. The % fall FEV1 after exercise and the AUC were significantly reduced when FP was inhaled compared to placebo inhalation (% fall 9.7% vs. 19.2%, respectively, P,=,0.038 and AUC 92.0%,min vs. 205.7%,min, respectively, P,=,0.03). There was considerable individual variability in reduction of EIB, with 5 out of 9 children having a clinically significant response. We conclude that a single high dose of inhaled FP has an acute protective effect on the bronchial response to exercise in a substantial proportion of asthmatic children. Pediatr Pulmonol. 2001; 32:115,121. © 2001 Wiley-Liss, Inc. [source] Effects of salinity levels on proteome of Suaeda aegyptiaca leavesPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 8 2006Hossein Askari Abstract Saline soils are the major problem of cultivated lands of Iran. Suaeda aegyptiaca is a salt-tolerant plant (halophytes) that grow naturally in salt-affected areas of Iran. We have employed proteomics to identify the mechanisms of salt responsiveness in leaves of S.,aegyptiaca grown under different salt concentrations. Ten-day-old plants were treated with 0, 150, 300, 450, and 600,mM NaCl. After 30,days of treatment, leaf samples were collected and analyzed using 2-D-PAGE. Out of 700,protein spots reproducible detected within replications, 102,spots showed significant response to salt treatment compared to 0,mM,NaCl. We analyzed expression pattern of salt-responsive proteins using a hierarchical and two nonhierarchical (Fuzzy ART and SOM) statistical methods and concluded that Fuzzy ART is the superior method. Forty proteins of 12,different expression groups were analyzed using LC/MS/MS. Of these, 27,protein spots were identified including proteins involved in oxidative stress tolerance, glycinebetain synthesis, cytoskeleton remodeling, photosynthesis, ATP production, protein degradation, cyanide detoxification, and chaperone activities. The expression pattern of these proteins and their possible roles in the adaptation of S.,aegyptiaca to salinity is discussed. [source] Refractory inflammatory heel pain in spondylarthropathy: A significant response to infliximab documented by ultrasoundARTHRITIS & RHEUMATISM, Issue 3 2002Maria Antonietta D'Agostino MD No abstract is available for this article. [source] Site, vine state and responsiveness to the application of growth regulator fruitsetting agentsAUSTRALIAN JOURNAL OF GRAPE AND WINE RESEARCH, Issue 1 2009J.A. CONSIDINE Abstract Background and Aims:, This study was initiated to investigate local problems in obtaining consistent fruit-setting responses to a recommended treatment combination of gibberellic acid (GA3) and (2-chloroethyl)-trimethyl ammonium chloride (CCC), with vineyard managers returning to more traditional methods of either cincturing or applying 4-chlorophenoxy acetic acid (4-CPA). Methods and Results:, Five vineyard study sites located in the Chittering,Bindoon region of Western Australia were characterised by multivariate analysis using measures of vegetative and reproductive biomass. Two experiments were carried out in the vineyard to compare responses to combinations of GA3 and CCC. 4-CPA was used as an industry control. Bunch number was used as a novel covariate to adjust responses to individual vine and site factors. Berry volume increased in all vines and sites treated with GA3, irrespective of timing, but dry matter yield increased only in the youngest vineyards. The only site to show a significant response to CCC application was that with the highest vegetative biomass. Conclusions:, We conclude that site and management factors rather than growth regulator type, concentration or timing determined yield responsiveness (sugar production). Significance of the Study:, This study demonstrates a strong physiological and environmental effect on response to growth regulator application, reinforcing the importance of developing site-specific management practices. It shows how multivariate techniques may be used to characterise and compare vineyards, and also, how analysis of covariance using a new parameter, bunch number, may be used to enhance statistical of analysis of field experiments. [source] Investigation of enhancement effects of nicotine on cholinergic neurotransmission in isolated rabbit gastric fundus: role of antioxidantsAUTONOMIC & AUTACOID PHARMACOLOGY, Issue 3 2010A. Anuvarbekova Summary 1,Nicotine, which is tobacco alkaloid, still induces interests for researchers because of smokers addiction to nicotine. Nicotine having influence on the neuronal acetylcholine receptors (nAChRs) increases release of most certain neurotransmitters from the nerve endings. Also, nicotine, affecting the mitochondrial respiratory chains, contributes to the formation of reactive oxygen species. 2,In the present study, we investigated the effects of nicotine on smooth muscles of gastric fundus on the electrical field stimulation (EFS) that induces transition contraction via stimulation nAChRs. In addition, we aimed to investigate the interaction between release of acetylcholine, induced by nicotine, and the effects of reactive oxygen species. 3,Therefore, the effects of allopurinol (10,6,10,5 m), deferoxamine (10,4 m) and mannitol (10,4,5 × 10,3 m) were tested on the transient contraction induced by nicotine. 4,In conclusion, mannitol (5 × 10,3 m) significantly reduced contractile response to nicotine on EFS only in high concentration. Whereas in small concentrations mannitol (10,4 m) statistically did not cause any results. Deferoxamine and allopurinol also did not have any significant response. [source] Direct and correlated responses to selection for longevity in Drosophila buzzatiiBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 4 2009ALEJANDRA C. SCANNAPIECO The possible associations between longevity, early fecundity, and stress-resistance traits were explored using artificial selection on longevity in a laboratory population of Drosophila buzzatii. Three replicated lines were selected for increased lifespan (L lines) and compared with the respective unselected controls (C lines) after the 14th generation of selection. Mean longevity exhibited a significant response to selection. The baseline mortality tended to decrease in the L lines and a negative correlated response to longevity selection was found for early fecundity. Egg-to-adult developmental time increased in L lines. Longevity selection increased stress resistance for both high and low temperatures, as measured by heat knockdown resistance and chill-coma recovery. Starvation resistance also tended to be higher in L than in C lines. The results obtained are consistent with the hypothesis of trade-offs between longevity and early fecundity, and also suggest a trade-off association between adult longevity and developmental time. Correlated selection responses were generally consistent with correlations among the traits previously inferred from altitudinal clines for longevity and stress-resistance phenotypes. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 97, 738,748. [source] Effect of the plant peptide regulator, phytosulfokine-,, on the growth and Taxol production from Taxus sp. suspension culturesBIOTECHNOLOGY & BIOENGINEERING, Issue 1 2006Beum Jun Kim Abstract Phytosulfokine-, (PSK-,) is a small plant peptide (5 amino acids) that displays characteristics typically associated with animal peptide hormones. PSK-, was originally isolated based on its mitogenic activity with plant cultures; it has been reported to increase production of tropane alkaloids from Atropa belladonna, although its general influence on secondary metabolite production is unknown. The studies reported in this article were initiated to evaluate the effects of PSK-, supplementation on production of TaxolÔ (paclitaxel) from plant cell cultures of Taxus sp. particularly when methyl jasmonate (MeJA) is added as an elicitor of secondary metabolism. The response to PSK-, supplementation was cell line dependent. Taxus cuspidata P93AF showed no statistically significant response to PSK-, supplementation while Taxus canadensis C93AD and T. cuspidata PO93X displayed a concentration-dependent response (up to 100 nM PSK-, added in first 24 h of culture) with a decrease in initial growth rate, an increase in cell density (dry weight/fresh weight), and increased Taxol production. More remarkably with T. canadensis (C93AD), a very strong synergistic response of PSK-, (100 nM) and methyl jasmonate (MeJA, 100 µM) elicitation was observed, resulting in Taxol level of 35.3,±,2.1 mg/L or 1.83,±,0.02 mg Taxol/g dry cell weight achieved at day 21, a level of approximately 10-fold higher than for either treatment by itself. Although the level of Taxol production achieved is not remarkable, this synergistic treatment was able to partially revive taxane production in cultures that have lost productivity due to extended time (over 10 years) in continuous subculture. © 2006 Wiley Periodicals, Inc. [source] Effects of chronic fluoxetine treatment in the presence and absence of (±)pindolol: a microdialysis studyBRITISH JOURNAL OF PHARMACOLOGY, Issue 4 2000L A Dawson Using in vivo microdialysis in the frontal cortex of the freely moving rat we evaluated the effects of chronic treatment with the serotonin specific reuptake inhibitor (SSRI) fluoxetine in the presence and absence of the 5-HT1A/,-adrenergic antagonist (±)pindolol. Chronic vehicle treated animals produced no significant response to a challenge with fluoxetine (10 mg kg,1) on day 8 and 15. Alternatively, a significant (P<0.05) decrease in extracellular 5-HT was observed in control animals upon challenge with the 5-HT1A agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT; 0.03 and 0.1 mg kg,1). Conversely, animals treated with fluoxetine (10 mg kg,1 o.d.) for 7 and 14 days produced a significant (P<0.05) 2 fold increase in extracellular 5-HT when challenged with fluoxetine (10 mg kg,1) on day 8 and 15. Moreover, no significant decrease in extracellular 5-HT was observed upon challenge with either dose of 8-OH-DPAT. Animals chronically treated with (±)pindolol (10 or 20 mg kg,1 b.i.d.) produced a significant dose-related increase in extracellular 5-HT upon challenge with fluoxetine on day 15 only. Furthermore, both doses produced a significantly blunted response to the low dose challenge of 8-OH-DPAT (0.03 mg kg,1). In addition, 20 mg kg,1 (±)pindolol treated animals also had no response to the higher 0.1 mg kg,1 dose of 8-OH-DPAT. Animals treated for 14 days with a combination of (±)pindolol (10 or 20 mg kg,1) and fluoxetine were not significantly different from vehicle treated animals when challenged with fluoxetine or 8-OH-DPAT. Taken together it would therefore appear that although (±)pindolol alone has sufficient intrinsic activity to produce a desensitization of the 5-HT1A receptor, when given in combination with fluoxetine it is able to prevent the desensitization induced by not only fluoxetine but also itself. This may suggest that the clinical augmentation of antidepressant action by pindolol, when co-administered with a SSRI, is via antagonism of the 5-HT1A receptor. British Journal of Pharmacology (2000) 130, 797,804; doi:10.1038/sj.bjp.0703378 [source] | ||||||||||||||||||||||||||||||||||||||||