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Moderate Increase (moderate + increase)
Selected AbstractsCortisol Reactivity Is Positively Related to Executive Function in Preschool Children Attending Head StartCHILD DEVELOPMENT, Issue 3 2005Clancy Blair This study examined relations among cortisol reactivity and measures of cognitive function and social behavior in 4- to 5-year-old children (N=169) attending Head Start. Saliva samples for the assay of cortisol were collected at the beginning, middle, and end of an approximately 45-min testing session. Moderate increase in cortisol followed by down-regulation of this increase was positively associated with measures of executive function, self-regulation, and letter knowledge but not with measures of receptive vocabulary, emotion knowledge, or false belief understanding. Regression analysis indicates that executive function accounted for the association between cortisol reactivity and self-regulation and letter knowledge. [source] Neuropeptide S Receptor Gene Expression in Alcohol Withdrawal and Protracted Abstinence in Postdependent RatsALCOHOLISM, Issue 1 2010Barbara Ruggeri Background:, Alcoholism is a chronic disease characterized by frequent intoxications followed by withdrawal episodes and relapse to alcohol use. Neuroplastic changes associated with these intoxication and withdrawal cycles are thought to play a key role in disease progression. Recently, it has been shown that neuropeptide S (NPS), a newly deorphanized neuropeptide receptor system, facilitates relapse to alcohol seeking in laboratory animals. Given that a history of ethanol intoxication may increase vulnerability to alcohol addiction, we sought to determine whether NPS receptor (NPSR) gene expression is altered during withdrawal. Methods:, Rats were subjected to 1 week of intoxication by oral alcohol administration. NPSR gene expression was analyzed by in situ hybridization in rats 12 hours and 7 days after the last alcohol administration. To investigate the functional significance of NPSR system adaptation following protracted withdrawal 7 days after intoxication, we tested the anxiolytic-like properties of NPS in nondependent and postdependent rats using the shock probe defensive burying test (DB). Results:, At both time points, increased NPSR gene expression was observed in several brain areas, including the endopiriform nucleus, the motor cortex, and the medial amygdaloid nucleus. Moderate increases in gene expression were also found in the lateral hypothalamus, paraventricular nucleus, basolateral and central amygdala. Differences from control animals were more pronounced after 7 days of abstinence. The upregulation of the NPSR system at this time point was confirmed by functional data indicating that intracerebroventricular (ICV) NPS administration (0.0, 0.3, and 0.1 nmol/rat) elicits more pronounced anxiolytic effects in postdependent animals than in controls subjected to the electric shock probe DB test. Conclusions:, Neuropeptide S receptor mRNA expression is increased in different brain areas of postdependent rats; as shown in the DB test, this expression change is functionally relevant. [source] AODV-RIP: improved security in mobile ad hoc networks through route investigation procedureCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 7 2010Byung-Seok Kang Abstract Most routing protocols in mobile ad hoc networks (MANETs) place an emphasis on finding paths in dynamic networks without considering security. As a result, there are a number of attacks that can be used to manipulate the routing in MANET. A malicious node that sends a modified control message to an intermediate node can disturb the network using a control message. To solve this problem, we introduce AODV protocol with route investigation procedure (AODV-RIP). It uses two additional control messages to defeat security attacks that can occur in AODV routing protocol. When an intermediate node that is on the path between the source node and the destination node receives a control message, it sends a Rroute Investigation Request (IREQ) message to the destination node in order to check the reliability of the control message. According to the existence of Route Investigation Reply (IREP), the intermediate node decides whether it transmits the control message to the source node or not. Consequently, the intermediate node that receives the control message confirms that it is using two additive control messages: IREQ and IREP. Through this investigation procedure, the source node can obtain a reliable path for transmitting data packets to an intentional destination node. The simulation results show an improvement in the packet delivery ratio and end-to-end delay at the expense of a moderate increase of the control message overhead compared with the current routing protocols. Copyright © 2009 John Wiley & Sons, Ltd. [source] The effect of thiazolidinediones on adiponectin serum level: a meta-analysisDIABETES OBESITY & METABOLISM, Issue 5 2008N. Riera-Guardia Background and aims:, Adiponectin is a hormone mainly produced by white adipose tissue. Decreased levels of adiponectin are linked with visceral obesity, insulin resistance states, and cardiovascular diseases. Recently, several studies have pointed out an increase in adiponectin serum levels in subjects undergoing treatment with thiazolidinediones (TZD). The aim of this study is to systematically review the current state of evidence of the effect of TZD on adiponectin serum level with special attention to avoid publication bias. Materials and methods:, An extensive literature search was performed. Meta Analysis Version 2.0 computer program was used to calculate statistical differences in means and 95% confidence interval (CI). Publication bias was assessed using different statistical approaches. Results:, In the meta-analysis including 19 studies the overall standardized mean difference was 0.94 (95% CI, 0.81,1.06) which means that subjects treated with TZDs on average had means of adiponectin concentration that were about 1 standard deviation higher than the comparison groups even after controlling for possible biases. Conclusions:, The results obtained agree with a moderate increase of serum adiponectin. The results clearly reveal an increase of endogenous serum adiponectin levels by intake of TZDs and may point to a potential new option to manage obesity-related diseases. [source] Is there a higher risk for herbivore outhreaks after cold mast years?ECOGRAPHY, Issue 6 2000An analysis of two plant/herbivore series from southern Norway Historical data on two plant-herbivore interactions from southern Norway were used to test the hypothesis that the degree of herbivore outbreaks in post-mast years is negatively related to summer temperatures in the mast year, because plants are more depressed after a high seed production if temperatures and thus the photosynthetic activity is low. The plant species were the sessile oak Quercus petraea and the bilberry Vaceinium myrtillus. For the former species post-mast years were identified from reports given by the local forest authorities for the period 1930,48, and from acorn export curves for the period 1949,98, For the latter species, post-mast years were identified mainly from bilberry export curves for the period 1920,31, from game reports for the period 1932,78. and from diary notes for the period 1979,87. The herbivore species used were the green oak leaf roller moth Tortrix viridana and the capercaillie Tetrao urogallus. Eight moth outbreaks on oak forests were reported by the forest authorities in the period 1930,98, and they all started in a post-mast year of the sessile oak. There were however also eleven post-mast years without moth outbreaks. According to game reports, observations and autumn counts, all increases in the autumn population size of capercaillie during 1920 88 occurred in or after a year with high bilberry production. Among i8 post-mast years, there were seven with strong increase, seven with slight or moderate increase, and four with no increase. For both herbivore species, post-mast years with marked population increases had significantly lower summer temperatures in the preceding (mast) year than had post-mast years with no or slight increases. For moth populations there also was a negative effect of high temperatures in April, possibly because moth eggs tend to hatch too early relative lo budburst if spring temperatures are high. For the capercaillie, high amount of precipitation in June , July seemed to have some negative impact on the autumn population sizes, as also found in previous studies. [source] Content and biosynthesis of polyamines in salt and osmotically stressed cells of Synechocystis sp.FEMS MICROBIOLOGY LETTERS, Issue 1 2003PCC 680 Abstract The effects of various NaCl and sorbitol concentrations in the growth medium on polyamine content and on two enzymes of the polyamine biosynthesis pathway, arginine decarboxylase (ADC) and S -adenosyl methionine decarboxylase (SAMDC), were investigated in the unicellular cyanobacterium Synechocystis sp. PCC 6803. Synechocystis cells showed no difference in growth rate when the concentration of NaCl was raised up to 550 mM. The growth rate decreased at 300 mM sorbitol, and complete inhibition of growth occurred at concentrations of ,700 mM sorbitol. Salt stress induced a moderate increase in the total cellular polyamine content, spermine in particular. Osmotic stress caused an apparent increase in the total cellular polyamine content with a marked increase of spermidine induced by 700 mM sorbitol. Importantly, a low level of spermine, which so far has never been detected in cyanobacteria, could be found in Synechocystis sp. PCC 6803. ADC, a key enzyme for putrescine synthesis, was unaffected by salt stress but showed a six-fold increase in enzyme activity upon osmotic stress imposed by 700 mM sorbitol. SAMDC, another important enzyme for spermidine and spermine synthesis, responded to salt and osmotic stresses similarly to the pattern observed for ADC. An analysis by reverse transcription-polymerase chain reaction revealed an increase of ADC mRNA level in cells under salt and osmotic stresses. Most importantly, the increase of ADC mRNA was attributed to its slower turnover rate under both stress conditions. Interestingly, the samdc gene(s) of Synechocystis appear to be unique since comparisons with known gene sequences from other organisms resulted in no homologous sequences identified in the Synechocystis genome. [source] Oligotrophication outweighs effects of global warming in a large, deep, stratified lake ecosystemGLOBAL CHANGE BIOLOGY, Issue 2 2010H. B. STICH Abstract Between 1951 and 1979, total phosphorous concentrations in Lake Constance increased from 7 to 87 ,g L,1. Following wastewater treatment, phosphorus levels were brought under control, returning to 7.6 ,g L,1 by spring 2007. The biological and chemical data from 1980 to 2004 were first modelled by seasonal time series analyses and then used to create a general model. Excluding collinear variables allowed the data set to be condensed to six variables that could be fitted into a general linear model that explained ,75% of the observed annual variation in chlorophyll a. A clear seasonal influence was apparent, with chlorophyll a tracking trends in temperature and the progress of spring. A nonseasonal influence was also observed in the interaction of two biological components, the proportion of phytoplankton biomass available to Daphnia (i.e. the percentage of ingestible size <30 ,m) and the grazing intensity. In combination, these biotic variables had a negative impact on chlorophyll a levels. In contrast, the concentration of soluble reactive phosphorus (SRP) correlated positively with chlorophyll a. The effect of SRP showed a significant seasonal component, as it was more abundant in spring than at other times of year. In general, the model predicts a negative exponential response of chlorophyll a to further depletion of SRP in Lake Constance, while the temperature trends predicted by current global warming scenarios will result in a moderate increase in productivity. Data from 2005 to 2007 were used to verify the model. The modelled chlorophyll a values were nonbiased and showed a close match to the measured values (r2: 75%). Thus the applicability, reliability, and informative value of the model for pelagic Lake Constance was confirmed. The approach might easily be applied to other waters. [source] The microfood web of grassland soils responds to a moderate increase in atmospheric CO2GLOBAL CHANGE BIOLOGY, Issue 7 2005Ilja Sonnemann Abstract The response of the soil microfood web (microflora, nematodes) to a moderate increase in atmospheric CO2 (+20%) was investigated by means of a free air CO2 enrichment experiment. The study was carried out in a seminatural temperate grassland for a period of 4 consecutive years (1 year before fumigation commenced and 3 years with fumigation). Several soil biological parameters showed no change (microbial biomass, bacterial biomass) or decline (microbial respiration) in the first year of elevated CO2 treatment as compared with controls. Each of these parameters were higher than controls, however, after 3 years of treatment. The relative abundance of predaceous nematodes also decreased in year 1 of the experiment, increased in year 2, but decreased again in year 3. In contrast, the relative abundance of root hair feeding nematodes, at first, increased under elevated CO2 and then returned to the initial level again. Increased microbial biomass indicates enhanced C storage in the labile carbon pool of the active microfood web in subsequent years. According to measurements on the amounts of soil extractable C, changes in resource availability seem to be key to the response of the soil microfood web. We found a strong response of bacteria to elevated CO2, while the fungal biomass remained largely unchanged. This contrasts to findings reported in the literature. We hypothesize that this may be because of contrasting effects of different levels of CO2 enrichment on the microbial community (i.e. stimulation of bacteria at moderate levels and stimulation of fungi at high levels of CO2 enrichment). However, various CO2 effects observed in our study are similar in magnitude to those observed in other studies for a much higher level of atmospheric carbon. These include the particular sensitivity of predaceous nematodes and the long-term increase of microbial respiration. Our findings confirm that the potential of terrestrial ecosystems to accumulate additional carbon might be lower than previously thought. Furthermore, CO2 -induced changes of temperate grassland ecosystems might emerge much earlier than expected. [source] Employment of the second-moment turbulence closure on arbitrary unstructured gridsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 4 2004B. BasaraArticle first published online: 12 JAN 200 Abstract The paper presents a finite-volume calculation procedure using a second-moment turbulence closure. The proposed method is based on a collocated variable arrangement and especially adopted for unstructured grids consisting of ,polyhedral' calculation volumes. An inclusion of 23k in the pressure is analysed and the impact of such an approach on the employment of the constant static pressure boundary is addressed. It is shown that this approach allows a removal of a standard but cumbersome velocity,pressure ,Reynolds stress coupling procedure known as an extension of Rhie-Chow method (AIAA J. 1983; 21: 1525,1532) for the Reynolds stresses. A novel wall treatment for the Reynolds-stress equations and ,polyhedral' calculation volumes is presented. Important issues related to treatments of diffusion terms in momentum and Reynolds-stress equations are also discussed and a new approach is proposed. Special interpolation practices implemented in a deferred-correction fashion and related to all equations, are explained in detail. Computational results are compared with available experimental data for four very different applications: the flow in a two-dimensional 180o turned U-bend, the vortex shedding flow around a square cylinder, the flow around Ahmed Body and in-cylinder engine flow. Additionally, the performance of the methodology is assessed by applying it to different computational grids. For all test cases, predictions with the second-moment closure are compared to those of the k,,model. The second-moment turbulence closure always achieves closer agreement with the measurements. A moderate increase in computing time is required for the calculations with the second-moment closure. Copyright © 2004 John Wiley & Sons, Ltd. [source] Downscaled GCM projections of winter and summer mass balance for Peyto Glacier, Alberta, Canada (2000,2100) from ensemble simulations with ECHAM5-MPIOMINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 11 2009Christoph Matulla Abstract We apply a direct downscaling approach to generate ensembles of local-scale glacier mass balance projections from coarse-scale general circulation model (GCM) data. The general modes of the atmospheric circulation over a large geographical region are linked statistically to Peyto Glacier's winter and summer balance separately. Our study focuses on the generation of ensemble projections derived from simulations with ECHAM5-MPIOM forced with Intergovernmental Panel on Climate Change - Special Report on Emission Scenarios (IPCC-SRES) A1B and B1. The resulting ensembles of mass balance projections show a moderate increase in winter balance and a steep decrease in summer balance. Together these results suggest continued frontal recession and downwasting of Peyto Glacier and a shift of the equilibrium line altitude by at least 100 m above that estimated for the 1966,2001 period suggesting that very little of the glacier will remain by 2100. Copyright © 2008 Crown in the right of Canada. Published by John Wiley & Sons, Ltd. [source] Nonempirical calculations of nonlinear optical properties of p -nitroaniline in acetone: Comparison of supermolecule and semicontinuum approachesINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 13 2007Marina Yu. Abstract The comparison of the conventional continuum, supermolecule, and semicontinuum models for the description of solvent effect on the (hyper)polarizability of p -nitroaniline (PNA) in acetone is performed. The supermolecule approach is used for the clusters containing PNA and one or two acetone molecules. The account of the specific solute,solvent interactions via the hydrogen bonds formation is shown to result in the enhancement of (hyper)polarizability values. The continuum approach exploited in the framework of polarizable continuum model (PCM) was shown to describe mainly the solvent effect on (hyper)polarizability. The semicontinuum approach, accounting explicitly the interaction between PNA and solvent molecules and treating the rest of the solvent as a continuum, results in a moderate increase of the (hyper)polarizability values compared to those obtained within the conventional PCM approach. All the calculations of (hyper)polarizabilities are performed at the Hartree,Fock level in the aug-cc-pVDZ' Dunning basis set. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007 [source] Evaluation of pre-operative anxiety and propofol-induced sedation using newly proposed indices of finger vascular toneJAPANESE PSYCHOLOGICAL RESEARCH, Issue 2 2002Gohichi Tanaka Abstract: This study examined estimates of finger vascular tone, obtained from photoplethysmography. Normalized and double-normalized pulse volume (NPV and DNPV), blood volume (BV), and pulse volume (PV) were obtained in 2 male and 7 female middle-aged patients at an outpatient office 1,3 days before an operation and in the operating room before and after anesthesia by propofol. There was a preoperative decrease in NPV, and the propofol injection yielded a moderate increase in BV. The latter seemed to contribute to a decrease in DNPV. A partial correlation controlling for body mass index was observed between the change in NPV and the dose of propofol; a larger reduction in NPV before anesthesia compared with the control condition was accompanied by the need for a greater infusion of propofol for sedation. In conclusion, among the measures examined, NPV appears to be the best indicator of heightened arteriolar vascular tone. [source] Haematological, hepatic and renal alterations after repeated oral or intraperitoneal administration of monoisoamyl DMSA.JOURNAL OF APPLIED TOXICOLOGY, Issue 6 2002Abstract Monoisoamyl 2,3-dimercaptosuccinic acid (MiADMSA), a vicinal thiol chelator, is gaining recognition recently as a better chelator than meso 2,3-dimercaptosuccinic acid (DMSA) in decreasing heavy metal burden in tissues because of its lipophilic character. There is, however, little information available on the toxicological properties of this chelator after repeated administration in animals. In the present study, we investigated the dose-dependent effect of MiADMSA on various biochemical parameters suggestive of alterations in haem biosynthesis and hepatic, renal and brain oxidative stress after 21 days of repeated intraperitoneal (i.p.) or oral (p.o.) administration to rats. The concentration of essential metals in blood and soft tissues was determined along with histopathological observations of hepatic and renal tissues. The results suggest that MiADMSA administration had no effect on blood ,-aminolevulinic acid dehydratase activity. However, an increase in zinc protoporphyrin and a decrease in haemoglobin levels were noted in animals given MiADMSA i.p. A moderate increase in serum alkaline phosphatase suggested mild hepatotoxicity at the highest dose (100 mg kg,1, i.p.). This was confirmed by histopathological examinations, which identified basophilic stippling, granulation of the cytoplasm, haemorrhage and congestion. At the highest dose, levels of hepatic thiobarbituric acid reactive substance and oxidized glutathione were increased above those of control values. Levels of hepatic reduced glutathione were decreased. Taken together, these observations point to oxidative stress. In animals administered MiADMSA i.p. there was an increase in the brain malondialdehyde levels at the two higher doses (50 and 100 mg kg,1). Essential metal status revealed a significant effect of MiADMSA (p.o.) in increasing blood zinc while significantly decreasing the kidney zinc level. The most significant adverse effect of MiADMSA was on copper concentration, which showed significant depletion from almost all major organs. Magnesium levels in blood decreased but increased in liver of MiADMSA-administered rats. Histopathological observations of liver and kidneys suggest few moderate lesions. It can be concluded that repeated administration of MiADMSA is compromised with some mild toxic effect, particularly the loss of copper. The effects during oral administration are comparatively less pronounced than by the i.p. route. Copyright © 2002 John Wiley & Sons, Ltd. [source] Bush encroachment under three contrasting land-use practices in a mesic South African savannaAFRICAN JOURNAL OF ECOLOGY, Issue 2009B. J. Wigley Abstract This study determined the effects of land-use practice had on the rate and extent of bush encroachment in a mesic savanna in KwaZulu-Natal, South Africa. Changes in woody cover were measured for 1 km2 sites in areas under communal, commercial and conservation land-use systems for the period between 1937 and 2000. Land users from each area were interviewed to gain the histories of each area and to determine how the changes in woody cover had impacted them and whether anything was being done to counteract the spread of trees and shrubs on their land. Bush encroachment occurred across all three of the land-use types in the 67-year period between 1937 and 2000. The results showed that land-use practice had enormous impacts on the process of bush encroachment. The communal site showed a decrease in grass (21%) and tree (5%) cover and an increase in shrub cover (13%). At the commercial site, there was a considerable decrease in grass cover (46%) and moderate increase in shrub cover (10%) and a massive increase in tree cover (36%). The area under conservation showed a substantial decrease in grass cover (47%), a slight decrease in shrub cover (19%) and a massive increase in tree cover (66%). The perceived causes of these changes were fairly similar amongst the different land users. The changes were mostly not perceived to be a problem for the communal land users. The main advantages mentioned were increased woody resources for building and firewood and increased browse availability. The commercial and conservation land users perceived the changes to have significant negative connotations including the loss of grazing land and biodiversity and secondary invasion of encroached areas by alien plant species. Despite these perceptions, very little has been done to combat bush encroachment in the commercial and conservation land use systems. [source] Temperature dependence of structure and dynamics of the hydrated Ca2+ ion according to ab initio quantum mechanical charge field and classical molecular dynamicsJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 6 2010Len Herald V. Lim Abstract Simulations using ab initio quantum mechanical charge field molecular dynamics (QMCF MD) and classical molecular dynamics using two-body and three-body potentials were performed to investigate the hydration of the Ca2+ ion at different temperatures. Results from the simulations demonstrate significant effects of temperature on solution dynamics and the corresponding composition and structure of hydrated Ca2+. Substantial increase in ligand exchange events was observed in going from 273.15 K to 368.15 K, resulting in a redistribution of coordination numbers to lower values. The effect of temperature is also visible in a red-shift of the ion-oxygen stretching frequencies, reflecting weakened ligand binding. Even the moderate increase from ambient to body temperature leads to significant changes in the properties of Ca2+ in aqueous environment. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2010 [source] Meta-analysis: The efficacy and safety of monoclonal antibody targeted to epidermal growth factor receptor in the treatment of patients with metastatic colorectal cancerJOURNAL OF DIGESTIVE DISEASES, Issue 4 2009Fang NIE OBJECTIVE: To evaluate systematically the efficacy and safety of anti-epidermal growth factor receptor (EGFR) monoclonal antibody added to a chemotherapeutic regimen in the treatment of patients with metastatic colorectal cancer (mCRC). METHODS: Eligible articles were identified by searching electronic databases. All randomized trials comparing the arm with an anti-EGFR monoclonal antibody to the arm without an anti-EGFR monoclonal antibody during the treatment of mCRC were included. A statistical analysis was performed with Review Manager 4.2.8. RESULTS: Seven randomized trials (n= 4186) were identified. The pooled response rates were 25.4% and 17.6% by intention-to-treat analyses for patients with or without an anti-EGFR monoclonal antibody, respectively, the OR was 3.36 (95% CI 1.42,7.95); the incidence of grades 3,4 adverse events were 71.2% and 54.3% for two groups, respectively, the OR was 2.23 (95% CI 1.74,2.86). The incidence of diarrhea, skin toxicity, hypomagnesemia was 62.3% versus 55.7%; 79.3% versus 19.7%; 27.2% versus 5.6%; and the summary OR was 1.36 (95% CI 1.03,1.80); 33.47 (95% CI 14.81,75.61); 6.73 (95% CI 3.84,11.82), respectively. CONCLUSION: Our results confirmed that monoclonal antibody targeted to EGFR could be effective in increasing response rates and could be a key therapeutic agent in the optimal treatment of mCRC, despite a moderate increase in grades 3,4 adverse events. [source] Regulation of MCP-1 production in brain by stress and noradrenaline-modulating drugsJOURNAL OF NEUROCHEMISTRY, Issue 2 2010Jose L. M. Madrigal J. Neurochem. (2010) 113, 543,551. Abstract While it is accepted that noradrenaline (NA) reduction in brain contributes to the progression of certain neurodegenerative diseases, the mechanisms through which NA exerts its protective actions are not well known. We previously reported that NA induced production of monocyte chemoattractant protein (MCP-1/CCL2) in cultured astrocytes mediated some of the neuroprotective actions of NA. We have now examined the regulation of MCP-1 production in vivo. Treatment of mice with the NA precursor l -threo-3,4-dihydroxyphenylserine induced the production of MCP-1 in astrocytes. In contrast, exposure to stress (a process known to elevate brain NA levels) produced only a moderate increase of MCP-1 because of the inhibitory activity of glucocorticoids released during the stress response. Similarly, corticosterone treatment of astrocytes caused a reduction of constitutive as well as the NA-induced MCP-1 production. When stressed rats had the production of glucocorticoids blocked by the selective inhibitor metyrapone, a large increase of MCP-1 concentration was observed in cortex, whereas propranolol (a beta adrenergic receptor blocker) avoided modifications of MCP-1 after stress. Desipramine (an inhibitor of NA reuptake) also caused an increase of MCP-1 in cortex. These data suggest that some phenomena caused by the alteration of NA or glucocorticoids could be mediated by MCP-1. [source] Semaphorin 3A and neurotrophins: a balance between apoptosis and survival signaling in embryonic DRG neuronsJOURNAL OF NEUROCHEMISTRY, Issue 2 2006Ayal Ben-Zvi Abstract Large numbers of neurons are eliminated by apoptosis during nervous system development. For instance, in the mouse dorsal root ganglion (DRG), the highest incidence of cell death occurs between embryonic days 12 and 14 (E12,E14). While the cause of cell death and its biological significance in the nervous system is not entirely understood, it is generally believed that limiting quantities of neurotrophins are responsible for neuronal death. Between E12 and E14, developing DRG neurons pass through tissues expressing high levels of axonal guidance molecules such as Semaphorin 3A (Sema3A) while navigating to their targets. Here, we demonstrate that Sema3A acts as a death-inducing molecule in neurotrophin-3 (NT-3)-, brain-derived neurotrophic factor (BDNF)- and nerve growth factor (NGF)-dependent E12 and E13 cultured DRG neurons. We show that Sema3A most probably induces cell death through activation of the c-Jun N-terminal kinase (JNK)/c-Jun signaling pathway, and that this cell death is blocked by a moderate increase in NGF concentration. Interestingly, increasing concentrations of other neurotrophic factors, such as NT-3 or BDNF, do not elicit similar effects. Our data suggest that the number of DRG neurons is determined by a fine balance between neurotrophins and Semaphorin 3A, and not only by neurotrophin levels. [source] Adenovirus-Mediated Leptin Expression Normalises Hypertension Associated with Diet-Induced ObesityJOURNAL OF NEUROENDOCRINOLOGY, Issue 3 2010W. Zhang In our previous study, moderate increases in plasma leptin levels achieved via administration of recombinant adenovirus containing the rat leptin cDNA were shown to correct the abnormal metabolic profile in rats with diet-induced obesity, suggesting that these animals had developed resistance to the metabolic effects of leptin, which could be reversed by leptin gene over-expression. However, the effect of this therapeutic strategy on blood pressure was not investigated. The present study aimed to determine whether a moderate increase of endogenous plasma leptin levels affected arterial blood pressure in rats with diet-induced obesity and hypertension. The major finding from the present study was that the natural rise in plasma leptin with weight-gain is insufficient to counterbalance high blood pressure associated with obesity, additional increases of circulating leptin levels with adenoviral leptin gene therapy led to normalisation of blood pressure in high-fat diet-induced obese and hypertensive rats. Mechanistically, the reduction of blood pressure by leptin in obese rats was likely independent of ,-adrenergic and acetylcholinergic receptor mediation. This is the first study to demonstrate that further increases in circulating leptin levels by leptin gene transfer during obesity could reduce blood pressure. [source] Changes in N -linked sugar chain patterns induced by moderate-to-high expression of the galactosyltransferase I gene in a brain-derived cell line, CG4JOURNAL OF NEUROSCIENCE RESEARCH, Issue 1 2005Krishnakumar N. Menon Abstract Oligosaccharides with biantennae and bisecting N -acetyl glucosamine (GlcNAc) residues attached to the mannose in the ,1-4 trimannosyl core (BA2) are enriched in the brain and considered brain-type sugar chains. We investigated the significance of the interplay between galactosyltransferase I (GalTase I) and BA2 formation in a brain-derived cell line, CG4. Increased GalTase expression in different glial- and neuronal-derived cell lines was accompanied by decreased or undetectable levels of BA2, depending on the level of GalTase expression. Forceful expression of GalTase I in CG4 cells expressing high levels of BA2 and low GalTase activity significantly reduced BA2 levels. In addition, a sixfold increase in an abnormal sugar chain A1(6)G1Fo and a moderate increase in A2G2Fo(6)F were evident. The increased levels of A1(6)G1Fo indicate a diversion or abrogation of the N -linked sugar chain biosynthetic pathway from normal. The accumulation of A1(6)G1Fo and increased A2G2Fo(6)F levels were accompanied by decreased levels of the high mannose-type sugar chains, M5A, M6B, M8A, and M9A. Increased GalTase I expression also led to stunted growth and abnormal morphology of CG4 cells, with increased mortality. Even moderate overexpression of GalTase I thus disrupts the normal biosynthetic pathway of N -linked sugar chains, and high overexpression is fatal to CG4 cells. © 2005 Wiley-Liss, Inc. [source] Period 2 Gene Deletion Abolishes ,-Endorphin Neuronal Response to EthanolALCOHOLISM, Issue 9 2010Maria Agapito Background:, Ethanol exposure during early life has been shown to permanently alter the circadian expression of clock regulatory genes and the ,-endorphin precursor proopiomelanocortin (POMC) gene in the hypothalamus. Ethanol also alters the stress- and immune-regulatory functions of ,-endorphin neurons in laboratory rodents. Our aim was to determine whether the circadian clock regulatory Per2 gene modulates the action of ethanol on ,-endorphin neurons in mice. Methods:,Per2 mutant (mPer2Brdml) and wild type (C57BL/6J) mice were used to determine the effect of Per2 mutation on ethanol-regulated ,-endorphin neuronal activity during neonatal period using an in vitro mediobasal hypothalamic (MBH) cell culture model and an in vivo milk formula feeding animal model. The ,-endorphin neuronal activity following acute and chronic ethanol treatments was evaluated by measuring the peptide released from cultured cells or peptide levels in the MBH tissues, using enzyme-linked immunosorbent assay (ELISA). Results:,Per2 mutant mice showed a higher basal level of ,-endorphin release from cultured MBH cells and a moderate increase in the peptide content in the MBH in comparison with control mice. However, unlike wild type mice, Per2 mutant mice showed no stimulatory or inhibitory ,-endorphin-secretory responses to acute and chronic ethanol challenges in vitro. Furthermore, Per2 mutant mice, but not wild type mice, failed to show the stimulatory and inhibitory responses of MBH ,-endorphin levels to acute and chronic ethanol challenges in vivo. Conclusions:, These results suggest for the first time that the Per2 gene may be critically involved in regulating ,-endorphin neuronal function. Furthermore, the data revealed an involvement of the Per2 gene in regulating ,-endorphin neuronal responses to ethanol. [source] Factors influencing elementary school children's attitudes toward science before, during, and after a visit to the UK National Space CentreJOURNAL OF RESEARCH IN SCIENCE TEACHING, Issue 1 2005Tina Jarvis This article reports on attitude changes of 300 children, aged 10 or 11 years, from four schools, who visited the UK National Space Centre. Attitudes toward science and space were explored by examining responses to five different attitude scales. These were administered before, immediately after, and 2 months and 4,5 months after a visit to the main exhibition area and Challenger Centre. Observations during the visits and interviews of teachers and a sample of children were carried out. Before the visit girls were more anxious than boys. Immediately afterward, children showed more interest in space and a moderate increase in their views about the value of science in society. Nearly 20% of the pupils showed an increased desire to become scientists in the future. These children also showed a positive advantage over the other children with regard to science enthusiasm and space interest. Two months later, they continued to be more positive about being future scientists but only the girls' scores were still significantly raised. Most children found the Challenger experience positive but had more problems with the exhibition area. Teachers' preparation and support during the visit as well as their personal interest had a significant long-term effect on children's attitudes. © 2004 Wiley Periodicals, Inc. J Res Sci Teach 42: 53,83, 2005 [source] Airway Mucus in Recurrent Airway Obstruction, Short-Term Response to Environmental ChallengeJOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 1 2004V. Gerber Mucus accumulation and neutrophilic inflammation in the airways are hallmarks of heaves. Endoscopically visible mucus accumulations, however, have not been studied during exposure to dusty hay and allergens (ie, environmental challenge). We hypothesized that (1) heaves-affected horses have increased mucus accumulation compared with controls, (2) mucus accumulations increase in heaves-affected horses during environmental challenge, and (3) environmental challenge also induces neutrophilic inflammation and mucus accumulation in control horses. Mucus accumulation was graded endoscopically (mucus grades [MGs] 1,5), and airway inflammation was evaluated by bronchoalveolar lavage fluid (BALF) cytology before (0 hours) and during (6, 24, 48 hours) environmental challenge. Large amounts of mucus (MG 4,5) were specific for heaves-affected horses in this study. Variation among controls was considerable, however, and intermediate grades (MG 2,3) were nonspecific, showing complete overlap between the 2 groups. Median mucus accumulations (25th, 75th percentiles) increased in heaves-affected horses from MG 2.5 (1.5, 3.5) at baseline to MG 3.5 (2.0, 4.0), 4.0 (3.0, 4.0), and 4.0 (4.0, 4.0) at 6, 24, and 48 hours, respectively. MG values did not increase in controls,overall MG 1.0 (1.0, 2.0),even though controls also showed a moderate increase of BALF neutro-phils. Mucus accumulations before and especially after exposure to dust and allergens are increased in heaves-affected horses compared with controls. Healthy controls show considerable variability in mucus accumulation but, despite an influx of neutrophils into the airways, no increase of mucus accumulation after exposure to hay dust. [source] Overexpression of cyclin D2 is associated with increased in vivo invasiveness of human squamous carcinoma cellsMOLECULAR CARCINOGENESIS, Issue 3 2002Shao Chen Liu Abstract Overexpression of cyclin D2 was studied in 10 human squamous cell carcinoma lines, to establish whether this gene plays a role in tumor progression. We found that those cell lines that overexpressed cyclin D2 (CCND2) had the most invasive in vivo behavior. The invasive ability of the cell lines was determined by evaluating the penetration of carcinoma cells into the tracheal wall in an in vivo assay with de-epithelialized tracheas transplanted into the subcutaneous tissue of nude mice. From five cell lines that exhibited low invasive ability, we selected two that had very little CCND2 expression (SCC9 and SCC15), to evaluate whether CCND2 gene transfer would increase the invasive behavior. After confirming the successful transfer of CCND2 by Northern, Western, and kinase-activity assays, we assessed the in vivo invasive behavior of the CCND2 -transfected cells and their respective vector alone,transfected controls. The cell lines containing the transferred CCND2 gene had a significantly higher invasive ability than respective controls. This was accompanied by a moderate increase in gelatinase activity. In addition, the in vitro proliferative abilities, under normal culture conditions, of the parental CCND2 - transfected and vector alone,transfected cells were found to be similar, as was the in vivo labeling index of Ki-67 in the tracheal transplants. These results indicated that the overexpression of CCND2 in squamous cell carcinoma lines modulates cell proliferation after induced quiescence and also has a powerful enhancing effect on in vivo aggressive growth behavior. © 2002 Wiley-Liss, Inc. [source] Titration of the Escherichia coli DnaA protein to excess datA sites causes destabilization of replication forks, delayed replication initiation and delayed cell divisionMOLECULAR MICROBIOLOGY, Issue 1 2003Morigen Summary In Escherichia coli, the level of the initiator protein DnaA is limiting for initiation of replication at oriC. A high-affinity binding site for DnaA, datA, plays an important role. Here, the effect of extra datA sites was studied. A moderate increase in datA dosage (, fourfold) delayed initiation of replication and cell division, but increased the rate of replication fork movement about twofold. At a further increase in the datA gene dosage, the SOS response was induced, and incomplete rounds of chromosome replication were detected. Overexpression of DnaA protein suppressed the SOS response and restored normal replication timing and rate of fork movement. In the presence of extra datA sites, cells showed a dependency on PriA and RecA proteins, indicating instability of the replication fork. The results suggest that wild-type replication fork progression normally includes controlled pausing, and that this is a prerequisite for normal replication fork function. [source] Environmental regulation of recA gene expression in Porphyromonas gingivalisMOLECULAR ORAL MICROBIOLOGY, Issue 3 2001Y. Liu The recA gene product in Porphyromonas gingivalis is involved in DNA repair. Further, disruption of this gene can affect the proteolytic activity and expression of other virulence factors in this organism. Since several known environmental factors can influence virulence gene expression in P. gingivalis, we investigated the influence of these signals on the expression of the recA gene in this organism. A heterodiploid strain of P. gingivalis (designated FLL118) containing a transcriptional fusion of the recA promoter region and the promoterless tetracycline-resistant gene [tetA(Q)2] and xylosidase/arabinosidase (xa) gene cassette was constructed. The recA promoter activity was assessed by measurement of xylosidase activity in FLL118. The expression remained relatively constant during different growth phases, at different pH levels and in the presence of DNA-damaging agents. In response to hemin limitation and in the presence of calcium there was a moderate increase in recA promoter activity. Temperature also affected the expression. The highest level of xylosidase activity was observed in cultures at 32°C with a decline of approximately 46% as growth temperature increased to 41°C. Reverse transcriptase polymerase chain reaction analysis revealed that this regulation may be occurring at the transcriptional level. These results suggest that expression of the recA gene in P. gingivalis W83 is responsive to several environmental signals but is not regulated by a DNA damage,inducible SOS-like regulatory system. [source] Orthodontically stressed periodontium of transgenic mouse as a model for studying mechanical response in bone: The effect on the number of osteoblastsORTHODONTICS & CRANIOFACIAL RESEARCH, Issue 2 2000Dubravko Pavlin A better understanding of cellular and molecular mechanisms involved in response to mechanical stress is a prerequisite for future improvements in orthodontic treatment. To expand the application of molecular biology techniques in this area of research, we developed and characterized a mouse tooth movement model. The aim of this study was to biomechanically characterize this model and to evaluate the effect of orthodontic stress on the proliferation of periodontal osteoblasts. We used an orthodontic coil spring appliance with a low force/deflection rate, which produced an average force of 10,12 g. This design provided a predictable tipping movement of the molar with the center of rotation at the level of root apices. Histological observations of paradental tissues revealed a response favoring a fast onset of tooth movement and deposition of new osteoid starting after 3 days of treatment. The effect of treatment on the histomorpometric parameter of the number of osteoclasts per unit bone perimeter was determined after 1, 2, 3, 4, 6, and 12 days of treatment. Starting with day 2, the osteoblast number showed a modest but consistent increase in treated periodontal sites at all time-points, ranging from 14 to 39% and becoming significant only at day 6. Only a moderate increase in the number of osteoblasts in the areas of otherwise intense bone matrix synthesis suggests that, during bone formation, proliferation of cells has a smaller role compared to a marked increase in differentiation of individual cells. The mouse model, which allows for a controlled, reproducible, orthodontic mechanical loading, can be applied to both wild-type and transgenic animals and should enhance the research of the transduction of mechanical orthodontic signal into a biological response. [source] Effect of zirconium dioxide on crystallization and melting behavior of flame sprayed polyamide 1010POLYMER COMPOSITES, Issue 4 2008Yadong Li The crystallization and melting behavior of flame sprayed Polyamide 1010 (PA1010) containing zirconium dioxide (ZrO2) were investigated using differential scanning calorimeter (DSC). ZrO2 has a heterogenous nucleation effect on PA1010, leading to a moderate increase in the crystallization temperature and a decrease in the supercooling temperature. A modified Avrami theory could be successfully used to well describe the early stages of non-isothermal crystallization of PA1010 and its composite coatings. A study of the nucleation activity, which indicated the influence of the filler on the polymer matrix, revealed that the zirconium dioxide nanoparticles had a good nucleation effect on PA1010. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers. [source] Cure kinetics, phase behaviors, and fracture properties of bismaleimide resin toughened by poly(phthalazinone ether ketone)POLYMER ENGINEERING & SCIENCE, Issue 12 2009Yongjin Han Poly(phthalazinone ether ketone)s (PPEK) were used to toughen bismaleimide (BMI) resin composed of 4,4,-bismaleimidodiphenyl methane (BMDM) and O,O, -diallyl bisphenyl A (DABPA). Dynamic differential scanning calorimetry (DSC) of the blends was carried out for kinetic analysis of the curing reaction. The reaction activation energy indicated that the reaction mechanism remained the same even after the incorporation of PPEK. The reaction-induced phase separation process in BMI/PPEK blends was investigated by optical microscopy (OM). The primary phase structure of the blends was fixed at the early stage of phase separation, and a secondary phase separation was observed as a result of the high viscosity of the blends. Scanning electron microscope (SEM) graphs showed that the morphology of the cured resin changed from a dispersed structure to a phase-inverted structure with the increase of PPEK content. Compared with the neat resin, the fracture toughness of the modified resin exhibits a moderate increase when PPEK was incorporated. Several toughening mechanisms, such as local plastic deformation, crack deflection, and branches, presumably took part in improving the toughness of BMI/PPEK blends on the basis of the morphology. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers [source] Efficient Ca2+ buffering in fast-spiking basket cells of rat hippocampusTHE JOURNAL OF PHYSIOLOGY, Issue 8 2008Yexica Aponte Fast-spiking parvalbumin-expressing basket cells (BCs) represent a major type of inhibitory interneuron in the hippocampus. These cells inhibit principal cells in a temporally precise manner and are involved in the generation of network oscillations. Although BCs show a unique expression profile of Ca2+ -permeable receptors, Ca2+ -binding proteins and Ca2+ -dependent signalling molecules, physiological Ca2+ signalling in these interneurons has not been investigated. To study action potential (AP)-induced dendritic Ca2+ influx and buffering, we combined whole-cell patch-clamp recordings with ratiometric Ca2+ imaging from the proximal apical dendrites of rigorously identified BCs in acute slices, using the high-affinity Ca2+ indicator fura-2 or the low-affinity dye fura-FF. Single APs evoked dendritic Ca2+ transients with small amplitude. Bursts of APs evoked Ca2+ transients with amplitudes that increased linearly with AP number. Analysis of Ca2+ transients under steady-state conditions with different fura-2 concentrations and during loading with 200 ,m fura-2 indicated that the endogenous Ca2+ -binding ratio was ,200 (,S= 202 ± 26 for the loading experiments). The peak amplitude of the Ca2+ transients measured directly with 100 ,m fura-FF was 39 nm AP,1. At ,23°C, the decay time constant of the Ca2+ transients was 390 ms, corresponding to an extrusion rate of ,600 s,1. At 34°C, the decay time constant was 203 ms and the corresponding extrusion rate was ,1100 s,1. At both temperatures, continuous theta-burst activity with three to five APs per theta cycle, as occurs in vivo during exploration, led to a moderate increase in the global Ca2+ concentration that was proportional to AP number, whereas more intense stimulation was required to reach micromolar Ca2+ concentrations and to shift Ca2+ signalling into a non-linear regime. In conclusion, dentate gyrus BCs show a high endogenous Ca2+ -binding ratio, a small AP-induced dendritic Ca2+ influx, and a relatively slow Ca2+ extrusion. These specific buffering properties of BCs will sharpen the time course of local Ca2+ signals, while prolonging the decay of global Ca2+ signals. 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