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Prior Exposure (prior + exposure)
Selected AbstractsInfants' Attention and Responsiveness to Television Increases With Prior Exposure and Parental InteractionINFANCY, Issue 1 2008Rachel Barr This study examined the relation between early television exposure and parental interaction style during infant-directed television programs on 2 outcomes: infant looking time and infant responsiveness. By quasi-experimental design half of the 12- to 18-month-old infants had prior exposure to the program content and the other half did not. Cluster analysis based on parental verbalizations revealed 3 types of parental coviewing style: high, medium, and low scaffold. Looking time was significantly higher for infants previously exposed to these videos than for those who were not. Infant looking time was also significantly higher, and infants responded more, when parents provided high levels of scaffolding in the form of questions and labels or descriptions. The results suggest that both prior exposure and parental style are associated with infant attention and responsiveness to television and have important implications for both parents and television producers. [source] Behavioural sensitization and enhanced dopamine response in the nucleus accumbens after intravenous cocaine self-administration in miceEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 3 2003Agustin Zapata Abstract The behavioural effects of cocaine are enhanced in animals with a prior history of repeated cocaine administration. This phenomenon, referred to as sensitization, is also associated with an increase in cocaine-evoked extracellular dopamine levels in the nucleus accumbens. Behavioural and neurochemical sensitization has been demonstrated in rats with a prior history of cocaine self-administration and in those that had received experimenter-administered cocaine. Although it is clear that the repeated non-contingent administration also results in behavioural sensitization in the mouse, the issue of whether behavioural and neurochemical sensitization also occur in this species following intravenous cocaine self-administration has not been assessed. The present study used the technique of in vivo microdialysis in conjunction with operant self-administration to characterize cocaine-evoked locomotor activity and dopamine levels in the nucleus accumbens in mice with a prior history of intravenous cocaine self-administration or those that had received yoked infusions of cocaine. Mice that had received contingent or non-contingent infusions of cocaine exhibited an enhanced behavioural response to cocaine and increased cocaine-evoked dopamine levels in the nucleus accumbens. There was no difference between groups in the magnitude of this effect. Prior exposure to cocaine did not modify baseline dopamine levels in the nucleus accumbens. These data demonstrate that mice with previous cocaine self-administration experience show an enhanced behavioural and dopamine response to cocaine in the nucleus accumbens. Furthermore, control over cocaine infusion does not significantly alter the magnitude of the sensitized behavioural and presynaptic dopamine responses observed in response to a challenge dose of cocaine. [source] Immunogenicity of synthetic saccharide fragments of Vibrio cholerae O1 (Ogawa and Inaba) bound to Exotoxin AFEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 2 2006Terri K. Wade Abstract Recombinant exotoxin A (rEPA) from Pseudomonas aeruginosa conjugated to Vibrio cholerae O1 serotype-specific polysaccharides (mono-, di- and hexasaccharide) were immunogenic in mice. Monosaccharide conjugates boosted the humoral responses to the hexasaccharide conjugates. Prior exposure to purified Ogawa lipopolysaccharide (LPS) enabled contra -serotype hexasaccharide conjugates to boost the vibriocidal response, but Inaba LPS did not prime for an enhanced vibriocidal response by a contra -serotype conjugate. Prior exposure to the carrier, and priming B cells with the LPS of either serotype, resulted in enhanced vibriocidal titers if the Ogawa hexasaccharides were used, but a diminished response to the Inaba LPS. These studies demonstrate that the ,functional' B cell epitopes on the LPS differ from those of the neoglycoconjugates and that the order of immunization and the serotype of the boosting conjugate can influence the epitope specificity and function of the antisera. [source] Monochloramine impairs mucosal blood flow response and healing of gastric lesions in rats: Relation to capsaicin-sensitive sensory neuronsJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 3 2001Koji Takeuchi Abstract Aims: We examined the effects of monochloramine (NH2Cl) on the gastric mucosal blood flow (GMBF) response and the healing of ethanol-induced gastric lesions in rats. Methods: Rats fasted for 18 h were given the 99% ethanol p.o. for induction of gastric lesions, and were fed normally from 1 h later onwards. Monochloramine, at non-ulcerogenic doses (5~20 mmol/L), was given p.o. twice daily for 7 days, starting 2 h after ethanol treatment. Results: Gastric lesions caused by ethanol healed almost completely within 7 days with re-epithelialization. The repeated administration of NH2Cl significantly delayed the healing of ethanol-induced gastric lesions in a dose-dependent manner. The damaged mucosa showed a marked rise in H+ permeability, resulting in luminal acid loss, but this process was accompanied by an increase of mucosal blood flow. Monochloramine did not affect the increased mucosal H+ permeability observed in the stomach after damage by ethanol, but significantly inhibited the mucosal hyperemic response associated with luminal acid loss. Prior exposure of the mucosa to NH2Cl (20 mmol/L) did not affect the gastric hyperemic response caused by mucosal application of misoprostol (a prostaglandin E1 derivative) or NOR-3 (a nitric oxide donor), but totally attenuated the increase of GMBF in response to intragastric capsaicin. Impaired healing and GMBF responses were also observed in rats following chemical ablation of capsaicin-sensitive sensory neurons. Conclusions: These results suggest that NH2Cl impaired the healing of acute gastric mucosal lesions at low concentrations, and this action may be attributable, at least partly, to the impairment of gastric hyperemic response caused by the dysfunction of capsaicin-sensitive sensory neurons. [source] Binge Pattern Ethanol Exposure in Adolescent and Adult Rats: Differential Impact on Subsequent Responsiveness to EthanolALCOHOLISM, Issue 8 2000Aaron M. White Background: Recent evidence indicates that adolescent animals are more sensitive than adults to the disruptive effects of acute ethanol exposure on spatial learning. It is not yet known whether adolescent animals are also more sensitive than adults to the enduring neurobehavioral effects of repeated ethanol exposure. In this study, animals were exposed to ethanol in a binge-pattern during either adolescence or adulthood. At a time when all subjects were adults, spatial working memory was examined in the absence and presence of an acute ethanol challenge. Methods: Rats were exposed to ethanol (5.0 g/kg intraperitoneally) or isovolumetric saline at 48 hr intervals over 20 days. Exposure began on either postnatal day 30 (adolescent group) or 70 (adult group). Twenty days after the final injection, a time at which all animals were adults, the subjects were tested on an elevated plus maze and then were trained to perform a spatial working memory task on an eight-arm radial maze. At the beginning of each session of training on the working memory task, subjects retrieved food rewards on four of the eight arms. After a delay, subjects were placed on the maze and allowed to retrieve food from the remaining four arms. Results: Prior exposure to ethanol did not influence behavior on the plus maze. Performance of the groups did not differ during acquisition of the spatial working memory task with a 5 min delay or during subsequent testing with a 1 hr delay. However, animals treated with ethanol during adolescence exhibited larger working memory impairments during an ethanol challenge (1.5 g/kg intraperitoneally) than subjects in the other three groups. Conclusions: The findings indicate that binge pattern exposure to ethanol during adolescence enhances responsiveness to the memory-impairing effects of ethanol in adulthood. [source] Symptom comparison across multiple solicitation methods among Burundians with traumatic event histories,JOURNAL OF TRAUMATIC STRESS, Issue 2 2008Peter D. Yeomans Debate continues over whether posttraumatic stress disorder (PTSD) symptoms are more biologically based and therefore relatively universal or are more culturally constructed. This study aimed to describe traumatic stress reactions in a Burundian sample and to investigate the influences of the solicitation method (open-ended questions and standardized measures) and psychoeducation (as a process of acculturation) on symptoms reported. Standardized measures showed that distress was manifested in somatization, anxiety, and depression, and less so in specific PTSD symptoms. Content analysis of open-ended questions revealed frequent material complaints. Prior exposure to Western ideas about trauma was predictive of more severe PTSD symptoms. The implications of the findings are discussed in terms of how methodological and cultural factors may influence posttraumatic reactions in nonindustrialized settings. [source] An Emerging Market's Reaction to Initial Modified Audit Opinions: Evidence from the Shanghai Stock Exchange,CONTEMPORARY ACCOUNTING RESEARCH, Issue 3 2000CHARLES J. P. CHEN Abstract This study investigates the valuation effect of modified audit opinions (MAOs) on the emerging Chinese stock market. Here, the term MAO refers to both qualified opinions and unqualified opinions with explanatory notes. The latter can be considered an alternative form of a qualified opinion in China. The institutional setting in China enables us to find compelling evidence in support of the monitoring role of independent auditing as an institution. First, we find a significantly negative association between MAOs and cumulative abnormal returns after controlling for effects of other concurrent announcements. Further, results from a by-year analysis suggest that investors did not reach negative consensus about MAOs' valuation effect until the second year, exhibiting the learning process of a market without prior exposure to MAOs. Second, we do not observe significant differences between market reaction to non-GAAP- and GAAP-violation-related MAOs. Third, no significant difference is found between market reaction to qualified opinions and market reaction to unqualified opinions with explanatory notes. [source] The development of stimulus-specific auditory responses requires song exposure in male but not female zebra finchesDEVELOPMENTAL NEUROBIOLOGY, Issue 1 2010Kristen K. Maul Abstract Juvenile male zebra finches develop their song by imitation. Females do not sing but are attracted to males' songs. With functional magnetic resonance imaging and event-related potentials we tested how early auditory experience shapes responses in the auditory forebrain of the adult bird. Adult male birds kept in isolation over the sensitive period for song learning showed no consistency in auditory responses to conspecific songs, calls, and syllables. Thirty seconds of song playback each day over development, which is sufficient to induce song imitation, was also sufficient to shape stimulus-specific responses. Strikingly, adult females kept in isolation over development showed responses similar to those of males that were exposed to songs. We suggest that early auditory experience with songs may be required to tune perception toward conspecific songs in males, whereas in females song selectivity develops even without prior exposure to song. © 2009 Wiley Periodicals, Inc. Develop Neurobiol 2010 [source] PRECLINICAL STUDY: FULL ARTICLE: Tolerance to 3,4-methylenedioxymethamphetamine is associated with impaired serotonin releaseADDICTION BIOLOGY, Issue 3 2010Karen Jones ABSTRACT Tolerance to the behavioural effects of 3,4-methylenedioxymethamphetamine (MDMA) following high dose exposure has been attributed to alterations in serotonergic systems. The present study aimed to determine whether decreased 5-HT release and/or 5-HT2A/C receptor desensitization might play a role in tolerance by measuring the response to selective ligands following MDMA exposure. To this end, the latency to nose poke and emerge from a hide box to an open field arena following administration of various ligands to MDMA pre-treated and control rats was measured. Acute exposure to MDMA (0.0,3.3 mg/kg), the 5-HT releasing stimulant fenfluramine (0.0,2.0 mg/kg) and the 5-HT2 receptor agonist m-CPP (0.0,1.25 mg/kg) increased nose poke and emergence latency. Following administration of doses that produce 5-HT2A receptor-mediated behaviours, the 5-HT2 receptor agonist (±)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane failed to alter nose poke and emergence latency, suggesting a limited role of this receptor subtype in these behaviours. Activation of 5-HT2C receptors was implicated in the behavioural response to both MDMA and m-CPP since the increased emergence latency was dose-dependently attenuated by pre-treatment with the selective 5-HT2C receptor antagonist RS102221 (0.0,1.0 mg/kg). Tolerance to the behavioural effect of MDMA and fenfluramine but not m-CPP was produced by prior exposure to MDMA (10 mg/kg administered at two-hour intervals, total 40 mg/kg), and tissue levels of 5-HT and 5-HIAA were decreased. These findings suggest that tolerance to the increased nose poke and emergence latency produced by MDMA is due to impaired 5-HT release. [source] Blood morphine levels in naltrexone-exposed compared to non-naltrexone-exposed fatal heroin overdosesADDICTION BIOLOGY, Issue 3 2003DIANE ARNOLD-REED The aim of this study was to investigate the association between prior exposure to naltrexone and increased risk of fatal heroin overdose using a review of toxicology reports for heroin-related fatalities between July 1997 to August 1999 for two groups: those treated with oral naltrexone and those who were not treated. Additional information for the oral naltrexone group was obtained from clinic files. Naltrexone-treated deaths were identified from the patient database at the Australian Medical Procedures Research Foundation (AMPRF), Perth, Western Australia (WA) through the Western Australian Department of Health, Data Linkage Project. Non-treated cases were identified from the database at the Forensic Science Laboratory, State Chemistry Centre (WA). We identified and investigated blood morphine concentrations following 21 fatal heroin overdoses with prior exposure to naltrexone and in 71 non-naltrexone-exposed cases over the same time period. The proportion of deaths where heroin use was a major contributing factor was little different in the non-naltrexone compared to the naltrexone-exposed group. Furthermore, in ,acute opiate toxicity' deaths, blood morphine levels were lower in non-naltrexone-exposed compared with naltrexone-exposed cases. Although there was a higher number of deaths designated as rapid (i.e. occurring within 20 minutes) in the naltrexone-exposed (89%) compared with the non-exposed group (72%) this was not statistically significant. Other drug use in relation to heroin-related fatalities is discussed. Findings do not support the hypothesis that prior exposure to naltrexone increases sensitivity to heroin toxicity. [source] Sensitization of meningeal nociceptors: inhibition by naproxenEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 4 2008Dan Levy Abstract Migraine attacks associated with throbbing (manifestation of peripheral sensitization) and cutaneous allodynia (manifestation of central sensitization) are readily terminated by intravenous administration of a non-selective cyclooxygenase (COX) inhibitor. Evidence that sensitization of rat central trigeminovascular neurons was also terminated in vivo by non-selective COX inhibition has led us to propose that COX inhibitors may act centrally in the dorsal horn. In the present study, we examined whether COX inhibition can also suppress peripheral sensitization in meningeal nociceptors. Using single-unit recording in the trigeminal ganglion in vivo, we found that intravenous infusion of naproxen, a non-selective COX inhibitor, reversed measures of sensitization induced in meningeal nociceptors by prior exposure of the dura to inflammatory soup (IS): ongoing activity of A,- and C-units and their response magnitude to mechanical stimulation of the dura, which were enhanced after IS, returned to baseline after naproxen infusion. Topical application of naproxen or the selective COX-2 inhibitor N -[2-(cyclohexyloxy)-4-nitrophenyl]-methanesulfonamide (NS-398) onto the dural receptive field of A,- and C-unit nociceptors also reversed the neuronal hyper-responsiveness to mechanical stimulation of the dura. The findings suggest that local COX activity in the dura could mediate the peripheral sensitization that underlies migraine headache. [source] Stress reverses plasticity in the pathway projecting from the ventromedial prefrontal cortex to the basolateral amygdalaEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 10 2006Mouna Maroun Abstract We have previously shown that high-frequency stimulation to the basolateral amygdala (BLA) induces long-term potentiation (LTP) in the ventromedial prefrontal cortex (vmPFC) and that prior exposure to inescapable stress inhibits the induction of LTP in this pathway [Maroun & Richter-Levin (2003)J. Neurosci., 23, 4406,4409]. Here, we show that the reciprocal pathway projecting from the vmPFC to the BLA is resistant to the induction of LTP. Conversely, long-term depression (LTD) is robustly induced in the BLA in response to low-frequency stimulation to the vmPFC. Furthermore, prior exposure to inescapable stress reverses plasticity in this pathway, resulting in the promotion of LTP and the inhibition of LTD. Our findings suggest that, under normal and safe conditions, the vmPFC is unable to exert excitatory synaptic plasticity over the BLA; rather, LTD, which encodes memory of safety in the BLA, is favoured. Following stressful experiences, LTP in the BLA is promoted to encode memory of fear. [source] Variation in thermal tolerance is linked to phosphoglucose isomerase genotype in a montane leaf beetleFUNCTIONAL ECOLOGY, Issue 2 2003G. Neargarder Summary 1Sierra Nevada populations of the Willow Beetle Chrysomela aeneicollis (Schaeffer) experience extreme elevated and subzero temperatures in nature. In these populations, frequencies of phosphoglucose isomerase (PGI) alleles vary with latitude and altitude and respond to climate change. PGI genotypes differ in expression of a stress-inducible heat shock protein (Hsp70). 2Here, differences in tolerance of elevated and subzero extreme temperatures were compared for field-acclimatized and laboratory-acclimated larvae and adults possessing three common PGI genotypes (PGI 1,1, 1,4 and 4,4). Three indices of thermal tolerance were measured , CTmax, LT50 and Hsp70 expression level. 3Thermal tolerance depended on life stage, prior exposure to sublethal stress and PGI genotype. Larvae were generally less tolerant of thermal extremes than adults. For both adults and larvae, prior exposure to sublethal temperatures increased survival after exposure to subsequent stress. Survival after exposure to thermal extremes was consistently related to PGI genotype (1,1 > 1,4 > 4,4), as were expression levels of Hsp70 (1,1 > 1,4 > 4,4). 4These results suggest that PGI genotypes differ in tolerance of thermal extremes routinely experienced by beetles in nature. A trade-off between thermal tolerance and energy allocation may explain the persistence of the PGI polymorphism. [source] State-dependency in C. elegansGENES, BRAIN AND BEHAVIOR, Issue 5 2004J. C. Bettinger Memory and the expression of learned behaviors by an organism are often triggered by contextual cues that resemble those that were present when the initial learning occurred. In state-dependent learning, the cue eliciting a learned behavior is a neuroactive drug; behaviors initially learned during exposure to centrally acting compounds such as ethanol are subsequently recalled better if the drug stimulus is again present during testing. Although state-dependent learning is well documented in many vertebrate systems, the molecular mechanisms underlying state-dependent learning and other forms of contextual learning are not understood. Here we demonstrate and present a genetic analysis of state- dependent adaptation in Caenorhabditis elegans. C. elegans normally exhibits adaptation, or reduced behavioral response, to an olfactory stimulus after prior exposure to the stimulus. If the adaptation to the olfactory stimulus is acquired during ethanol administration, the adaptation is subsequently displayed only if the ethanol stimulus is again present. cat-1 and cat-2 mutant animals are defective in dopaminergic neuron signaling and are impaired in state dependency, indicating that dopamine functions in state-dependent adaptation in C. elegans. [source] Evidence for prolonged clinical benefit from initial combination antiretroviral therapy: Delta extended follow-upHIV MEDICINE, Issue 3 2001Delta Coordinating Committee Background The findings from therapeutic trials in HIV infection with surrogate endpoints based on laboratory markers are only partially relevant for clinical decisions on treatment. Although the collection of clinical follow-up data from such a trial would be relatively straightforward, this rarely occurs. An important reason for this may be the perception that such data have little value because the number of participants remaining on their original allocated therapy has usually fallen substantially. Methods Delta was an international, multicentre trial in which 3207 HIV infected individuals were randomly allocated to treatment with zidovudine (ZDV) alone, ZDV combined with didanosine (ddI) or ZDV combined with zalcitabine (ddC). Although the trial closed in September 1995, information on vital status, AIDS events, treatment changes and CD4 counts was still collected every 12 months until at least March 1997. This has allowed analyses of the longer term clinical effect of treatment. Results The median follow-up to date of death or last known vital status was 43 months (10th percentile 18 months; 90th percentile 55 months). The proportion of participants remaining on their allocated treatment fell steadily over time; by 4 years after trial entry, 3% remained on ZDV, 20% on ZDV + ddI and 21% on ZDV + ddC. Changes mainly involved the stopping, addition or switching of a nucleoside reverse transcriptase inhibitor (NRTIs). There was little use of protease inhibitors (PIs) or non-nucleoside reverse transcriptase inhibitors (NNRTIs) before the third year of the trial. Between the third and fourth years, regimens included a drug from one of these classes for approximately 17% of person-time in all treatment groups. Relative to ZDV monotherapy, the beneficial effects of combination therapy on mortality and disease progression rates increased significantly with time since randomization. The maximum effects on mortality were observed between 2 and 3 years, with a 48% reduction for ZDV + ddI and a 26% reduction for ZDV + ddC. These rates were observed when the original allocated treatment was received 42% and 47% of the time in the ZDV + ddI and ZDV + ddC groups, respectively. The mean CD4 count remained significantly higher (approximately 50 cells/,L) in the combination therapy groups 4 years after randomization, suggesting a projection of a clinical benefit beyond this time point. Conclusions The sustained clinical effect of the initial allocation to combination therapy, particularly ZDV + ddI, was remarkable in light of the convergence of drug regimens actually received across the three treatment groups. Interpretation of this finding is not straightforward. One of the possible explanations is that the effectiveness of ddI and ddC is diminished if first used later in infection or with greater prior exposure to ZDV, although the data do not clearly support either hypothesis. This analysis highlights the value of long-term clinical follow-up of therapeutic trials in HIV infection, which should be considered in the planning of all new studies. [source] Infants' Attention and Responsiveness to Television Increases With Prior Exposure and Parental InteractionINFANCY, Issue 1 2008Rachel Barr This study examined the relation between early television exposure and parental interaction style during infant-directed television programs on 2 outcomes: infant looking time and infant responsiveness. By quasi-experimental design half of the 12- to 18-month-old infants had prior exposure to the program content and the other half did not. Cluster analysis based on parental verbalizations revealed 3 types of parental coviewing style: high, medium, and low scaffold. Looking time was significantly higher for infants previously exposed to these videos than for those who were not. Infant looking time was also significantly higher, and infants responded more, when parents provided high levels of scaffolding in the form of questions and labels or descriptions. The results suggest that both prior exposure and parental style are associated with infant attention and responsiveness to television and have important implications for both parents and television producers. [source] Determination of baseline susceptibility to Cry1Ab protein for Asian corn borer (Lep., Crambidae)JOURNAL OF APPLIED ENTOMOLOGY, Issue 8 2005K. He Abstract:, Although transgenic Bacillus thuringiensis (Bt) corn can provide a new tool for control of the Asian corn borer (ACB), Ostrinia furnacalis (Guenée), concern has been raised regarding the possibility of the target insect evolving resistance to the Bt protein under intensive selection pressure from Bt corn. Therefore, it is necessary to establish baseline data to enable detection of changes in susceptibility in field populations after prolonged exposure to Bt corn. Susceptibility to purified Cry1Ab protein from Bt was determined for 10 populations of ACB from the major corn-growing regions of China, ranging geographically from Heilongjiang Province in the northeast to Shaanxi Province in the east-central part. Neonate ACB were exposed to semi-artificial diet incorporated with increasing Cry1Ab protein concentrations, and mortality and growth inhibition were evaluated after 7 days. The range of LC50 (50% lethal concentration) among the populations was 0.10 to 0.81 ,g/g (Cry1Ab protein/diet). Differences (P < 0.05) in susceptibility among the populations were significant. LC50s generated from the Huanghuaihai Summer Corn Region were higher than those from the Spring Corn Regions. Bt was one of the significant natural biomortality factors of overwintering generation ACB. There was a significant correlation between percentage of the larvae infected with Bt and their LC50 values to Cry1Ab protein in geographic distinct populations (r = 0.7350*, d.f. = 8, r0.05 = 0.632). Based on the background of Bt formulations used for corn insect pests control in these areas, these differences were not caused by prior exposure to Bt insecticides. Instead, the small differences likely reflect natural Bt selection pressure. Because the variation in susceptibility to Cry1Ab was small (<10-fold), the ACB apparently is susceptible to Cry1Ab across its range within China. [source] A Role for G Protein-Coupled Lysophospholipid Receptors in Sphingolipid-Induced Ca2+ Signaling in MC3T3-E1 Osteoblastic CellsJOURNAL OF BONE AND MINERAL RESEARCH, Issue 11 2001Jeremy M. Lyons Abstract Sphingolipids have been proposed to modulate cell function by acting as intracellular second messengers and through binding to plasma membrane receptors. Exposure of MC3T3-E1 osteoblastic cells to sphingosine (SPH), sphingosine-1-phosphate (SPP), or sphingosylphosphorylcholine (SPC) led to the release of Ca2+ from the endoplasmic reticulum (ER) and acute elevations in cytosolic-free Ca2+ ([Ca2+]i). Desensitization studies suggest that SPP and SPC bind plasma membrane endothelial differentiation gene (Edg) receptors for lysophosphatidic acid (LPA). Consistent with the coupling of Edg receptors to G proteins, SPP- and SPC-induced Ca2+ signaling was inhibited by pretreatment of the cells with pertussis toxin (PTx). Of the Edg receptors known to bind SPH derivatives in other cell types, MC3T3-E1 cells were found to express transcripts encoding Edg -1 and Edg -5 but not Edg -3, Edg -6, or Edg -8. In contrast to SPP and SPC, the ability of SPH to elicit [Ca2+]i elevations was affected neither by prior exposure of cells to LPA nor by PTx treatment. However, LPA-induced Ca2+ signaling was blocked in MC3T3-E1 cells previously exposed to SPH. Elevations in [Ca2+]i were not evoked by SPP or SPC in cells treated with 2-aminoethoxydiphenylborate (2-APB), an inhibitor of inositol 1,4,5-trisphosphate (IP3)-gated Ca2+ channels in the ER. No effect of 2-APB was observed on SPH- or LPA-induced [Ca2+]i elevations. The data support a model in which SPP and SPC bind Edg -1 and/or Edg -5 receptors in osteoblasts leading to the release of Ca2+ from the ER through IP3 -gated channels. [source] PTH-dependent adenylyl cyclase activation in SaOS-2 cells: Passage dependent effects on G protein interactionsJOURNAL OF CELLULAR PHYSIOLOGY, Issue 1 2002Hong Gao Parathyroid hormone (PTH) sensitive adenylyl cyclase activity (ACA) in SaOS-2 cells varies as a function of cell passage. In early passage (EP) cells (<,6), ACA in response to PTH and forskolin (FOR) was relatively low and equivalent, whereas in late passage (LP) cells (>,22), PTH exceeded FOR dependent ACA. Potential biochemical mechanisms for this passage dependent change in ACA were considered. In EP, prolonged exposure to pertussis toxin (PT) markedly enhanced ACA activity in response to PTH, Isoproterenol and Gpp(NH)p, whereas ACA in response to FOR was decreased. In contrast, the identical treatment of LP with PT diminished all ACA in response to PTH, Gpp(NH)p, and FOR. The dose dependent effects of PT on subsequent [32P]ADP-ribosylation of its substrates, GTPase activity, as well as FOR-dependent ACA, were equivalent in EP and LP. The relative amounts of G,i and G,s proteins, as determined both by Western blot, PT and cholera toxin (CT) dependent [32P]ADP-ribosylation, were quantitatively similar in EP and LP. Western blot levels of G,s and G,i proteins were not influenced by prior exposure to PT. Both PT and CT dependent [32P]ADP-ribosylation were dose-dependently decreased following exposure to PT. However, the PT-dependent decline in CT-dependent [32P]ADP-ribosylation occurred with enhanced sensitivity in LP. The protein synthesis inhibitor cycloheximide partially reversed the PT associated decrease in FOR dependent ACA in EP. In contrast, cycloheximide completely reversed the PT associated decrease in FOR and as well as PTH dependent ACA in LP. G,s activity, revealed by cyc, reconstitution, was not altered either by cell passage or exposure to PT. The results suggest that the coupling between the components of the complex may be pivotally important in the differential responsiveness of early and late passage SaOS-2 cells to PTH. J. Cell. Physiol. 193: 10,18, 2002. © 2002 Wiley-Liss, Inc. [source] Responses to handling and confinement stressors in juvenile great sturgeon Huso husoJOURNAL OF FISH BIOLOGY, Issue 4 2009B. Falahatkar The effects of acute stressors on physiological responses of juvenile great sturgeon or beluga Huso huso L. were investigated in two experiments. In the first experiment, fish were handled by placing them in containers at either low density (LD, one fish l,1) or high density (HD, four fish l,1) for 60 s. Concentrations of plasma cortisol, glucose and lactate were determined from blood collected at 0, 1, 3, 6 and 12 h after application of the stressor. Plasma cortisol concentrations increased after the disturbance in H. huso from both handling treatments, but changes were not significant. Plasma glucose rose significantly by 22·9 and 31·6% in LD and HD handling treatments, respectively, after 3 h. Significant increases in plasma lactate occurred within 1 h in both treatment groups, but that of the HD group was much higher. In the second experiment, fish were held at two different densities, LD (2 kg m,2 tank bottom surface area) and HD (7 kg m,2), for 8 weeks and then subjected to an aerial emersion handling stressor in a net for 60 s; blood samples were taken before handling (resting, 0 h) and at 1, 3, 6 and 9 h after handling. Plasma cortisol increased significantly in fish from the HD treatment from 8·8 ± 0·3 to 19·2 ± 2·4 ng ml,1 (mean ±s.e.) by 1 h after stress, but post-handling changes in the LD group were not significant. Significant increases in both plasma glucose and lactate were observed by 1 h in both treatment groups, with peak levels of plasma glucose evident at 3 h [69·4 ± 2·9 and 60·9 ± 1·7 mg dl,1 (mean ±s.e.) in LD and HD groups, respectively]. Plasma glucose levels were significantly higher in the LD group than in the HD group at 3 and 6 h. Post-handling haemoglobin content increased by 1 h and white blood cell numbers were reduced by 3 and 6 h in the HD treatment group compared with resting values, but changes in these blood features in the LD group were not significant. Acute handling did not affect haematocrit in either treatment. The results suggest that H. huso is relatively resistant to handling and confinement, and could tolerate normal hatchery practices associated with aquaculture. Because changes in cortisol concentrations were relatively low compared with those in most teleosts, glucose and lactate concentrations may be more useful as stress indicators in juvenile H. huso. This study also demonstrated that prior exposure to a chronic stressor, specifically high stocking density, could alter the physiological response to subsequent acute handling in H. huso. [source] Environmental enrichment and prior experience of live prey improve foraging behaviour in hatchery-reared Atlantic salmonJOURNAL OF FISH BIOLOGY, Issue 2003C. Brown Atlantic salmon salmo salar L. parr were reared for 3 months under standard hatchery conditions or in a structurally enriched tank (containing plants, rocks and novel objects). Half of each of these fish had prior exposure to live prey in the form of live bloodworm while the other half were fed hatchery-pellets. After 12 days all fish were tested on a novel live prey item (brine shrimp). A significant interaction between the two factors (prior exposure to live prey and rearing condition) revealed that foraging performance was only enhanced in fish that had been reared in a complex environment and exposed to live prey. It appears that the ability to generalize from one live prey type to another is only enhanced in fish that had been reared in an enriched environment. The findings support the assertion that the provision of enriched environments in combination with exposure to live prey prior to release may significantly improve the post-release survival rates of hatchery-reared fishes. As both the environmental enrichment and the prior foraging experience procedures were comparatively simple, the provision of such pre-release experiences are likely to prove cost effective to hatcheries. [source] A Gonadotropin-Releasing Hormone Insensitive, Thapsigargin-Sensitive Ca2+ Store Reduces Basal Gonadotropin Exocytosis and Gene Expression: Comparison with Agonist-Sensitive Ca2+ StoresJOURNAL OF NEUROENDOCRINOLOGY, Issue 2 2003J. D. Johnson Abstract We examined whether distinct Ca2+ stores differentially control basal and gonadotropin (GTH-II)-releasing hormone (GnRH)-evoked GTH-II release, long-term GTH-II secretion and contents, and GTH-II- , mRNA expression in goldfish. Thapsigargin (Tg)-sensitive Ca2+ stores mediated neither caffeine-evoked GTH-II release, nor salmon (s)GnRH- and chicken (c)GnRH-II-stimulated secretion; the latter responses were previously shown to involve ryanodine (Ry)-sensitive Ca2+ stores. Surprisingly, Tg decreased basal GTH-II release. This response was attenuated by prior exposure to sGnRH and caffeine, but was insensitive to the phosphatase inhibitor okadaic acid, the inhibitor of constitutive release brefeldin A and cGnRH-II. GTH-II- , mRNA expression was decreased at 24 h by 2 µm Tg, and by inhibiting (10 µm Ry) and stimulating (1 nm Ry) Ry receptors. Transient increases in GTH-II- , mRNA were observed at 2 h and 12 h following 10 µm and 1 nm Ry treatment, respectively. Effects of Tg, Ry and GnRH on long-term GTH-II secretion, contents and apparent production differed from one another, and these changes were not well correlated with changes in GTH-II- , mRNA expression. Our data show that GTH-II secretion, storage and transcription can be independently controlled by distinct Ca2+ stores. [source] EFFECT OF EXPOSURE TO THE AROMA OF A PRELOAD ON SUBSEQUENT INTAKE OF A FOOD WITH THE SAME AROMAJOURNAL OF SENSORY STUDIES, Issue 4 2002J.-X. GUINARD ABSTRACT We tested the hypothesis that exposure to an aroma through a food or beverage in the first part of a meal (preload) would reduce the consumption of a food with the same aroma in the second portion of the meal, because of olfactory-specific satiety. In a first experiment, 35 young, normal-weight adults participated in 2 lunch sessions during which they consumed a fixed preload of either ranch-flavored or plain potato chips and sparkling water, followed by ad libitum consumption of a pasta salad with ranch dressing and sparkling water. In the second experiment, 33 subjects consumed a fixed preload of either lemon-flavored or plain sparkling water and pasta salad with ranch dressing, followed by ad libitum consumption of lemon-flavored yogurt and plain sparkling water. No difference was observed in the amount of food consumed (corrected for session order effects) as a function of prior exposure to ranch flavor in the chips or lemon flavor in the water. We conclude that exposure to a preload aroma may not have a significant effect on subsequent intake of a food with the same aroma. [source] Input and SLA: Adults' Sensitivity to Different Sorts of Cues to French GenderLANGUAGE LEARNING, Issue S1 2005Susanne E. Carroll All second language (L2) learning theories presuppose that learners learn the target language from the speech signal (or written material, when learners are reading), so an understanding of learners' ability to detect and represent novel patterns in linguistic stimuli will constitute a major building block in an adequate theory of second language acquisition (SLA) input. Pattern detection, a mainstay of current connectionist modeling of language learning, presupposes a sensitivity to particular properties of the signal. Learning abstract grammatical knowledge from the signal presupposes, as well, the capacity to map phonetic properties of the signal onto properties of another type (segments and syllables, morpheme categories, and so on). Thus, even seemingly "simple" grammatical phenomena may embody complex structural knowledge and be instantiated by a plethora of diverse cues. Moreover, cues have no a priori status; a phenomenon of a given sort takes on a value as a cue when acquisition of the grammatical system reveals it to be useful. My study deals with initial sensitivity to cues to gender attribution in French. Andersen (1984) asked: "What's gender good for anyway?" One answer comes from a number of studies, done mostly in the last 20 years, of gender processing by both monolingual and bilingual speakers (among many others, Bates, Devescovi, Hernandez, & Pizzamiglio, 1996; Bates & Liu, 1997; Friederici & Jacobsen, 1990; Grosjean, Dommergues, Cornu, Guillemon, & Besson, 1994; Guillemon & Grosjean, 2001; Taft & Meunier, 1998). These studies provide evidence that in monolinguals and early (but not late) L2 learners, prenominal morphosyntactic exponents of gender prime noun activation and speed up noun recognition. Over the same period, a growing number of studies detailing the course of L2 gender acquisition for a variety of different target languages and learner types (e.g., Bartning, 2000; Chini, 1995; Dewaele & Véronique, 2000; Granfeldt, 2003; Hawkins & Franceschina, 2004) have provided support for the hypothesis that developmental paths differ for early and later learners of gender. Yet despite its obvious importance to SLA theorizing, few studies have dealt directly with adult learners' ability to detect and analyze potential cues to gender at the initial stage of exposure to the L2 (and this despite considerable discussion in recent years of the nature of the "initial state" of L2 learning). The study reported on in this article, which was actually conducted in the late 1980s, was an attempt to shed some light on what the beginning learner can do with the gender attribution problem. This study was, at that time, and is even now, an anomaly; most research dealing with "input" provided descriptions of what people say to learners, not what learners can perceive and represent. Indeed, most studies that shed light on the initial analytical capacities of absolute beginners were concerned with "perceptual" learning, that is, with the acquisition of phonetic or phonological distinctions (e.g., Broselow, Hurtig, & Ringen's [1987] study of tone learning or various studies on the perception of the /r/ vs. /l/ phonemes in American English by Japanese speakers). In this update, it is therefore worth mentioning Rast's (2003) dissertation and Rast and Dommergues (2003), which is based on it, which examined the results of the first 8 hr of instructed learning of Polish by francophone adults. My study asked if anglophone adults, with little or no prior exposure to French, given auditory stimuli, were equally sensitive to phonological, morphosyntactic, or semantic cues to French gender classes. The issue of what learners can detect in the signal and encode is an empirical one. I presented 88 adult English speakers with highly patterned data in list form, namely, auditory sequences of [Det + N]French + translation equivalentEnglish forms. The patterns, all true generalizations, were drawn from linguistic descriptions of French. These cues are believed by grammarians of the language to be "psychologically real" to native speakers. I then measured in 3 different ways what my participants had acquired. Given the extreme limitations on the input (no visual supports to identify referents of names), the participants performed pretty well. Moreover, they proved to be highly sensitive to "natural" semantic and morphological patterns and could generalize accurately from learned instances to novel exemplars. These patterns, however, are not directly instantiated in the speech signal; they are abstractions imposed on the stimuli by human linguistic cognition. Moreover, although it would be inaccurate to describe the learning patterns as "transfer"(because English nouns have no gender feature), prior knowledge seemed to be implicated in the results. Above all, these Anglophones appear to perceive the gender learning problem as a semantic one and to make use of "top-down" information in solving it. It follows that the pattern detection that they can do when listening to speech is clearly biased by what they already know. These results, therefore, provide support for hypotheses that the initial state is to be defined in terms of the transfer of first language (L1) grammatical knowledge and/or the transfer of L1-based processing procedures. [source] Survival after orthotopic liver transplantation: The impact of antibody against hepatitis B core antigen in the donor,,§LIVER TRANSPLANTATION, Issue 10 2009Lei Yu Liver transplantation using grafts from donors with antibody against hepatitis B core antigen (anti-HBc) increases the recipients' risk of developing hepatitis B virus (HBV) infection post-transplantation. Our aim was to assess whether using such grafts was associated with reduced posttransplantation survival and whether this association depended on recipients' prior exposure to HBV on the basis of their pretransplantation serological patterns. Data were derived from the United Network for Organ Sharing on adult, cadaveric, first-time liver transplants performed between 1994 and 2006. Among recipients who did not have HBV infection before transplantation, those with anti-HBc,positive donors had significantly worse unadjusted posttransplantation patient survival than recipients with anti-HBc,negative donors [hazard ratio, 1.35; 95% confidence interval (CI), 1.21-1.50]. However, after adjustments for other predictors of posttransplantation survival, including donor age, donor race, and recipient underlying liver diseases, patient survival was not significantly different between the 2 groups (hazard ratio, 1.09; 95% CI, 0.97-1.24). Among recipients without antibody against hepatitis B surface antigen (anti-HBs), use of anti-HBc,positive donor grafts was associated with a trend toward worse survival (adjusted hazard ratio, 1.18; 95% CI, 0.95-1.46), whereas no such trend was observed among recipients positive for anti-HBs. In conclusion, in patients without HBV infection before transplantation, using anti-HBc,positive donors was not independently associated with worse posttransplantation survival. Matching these donors to recipients with anti-HBs pre-transplantation may be especially safe. Liver Transpl 15:1343,1350, 2009. © 2009 AASLD. [source] Preparing to Implement a Self-Management Program for Back Pain in New York City Senior Centers: What Do Prospective Consumers Think?PAIN MEDICINE, Issue 3 2010Sarah Townley RN Abstract Objective., Prior to testing the feasibility/potential efficacy of a newly developed self-management pain program for seniors with back pain, this study sought to: 1) determine prospective consumers' prior exposure to self-management pain programs, 2) determine their willingness to participate in the new program, and 3) ascertain perceived barriers/facilitators to program participation. Design., Cross-sectional survey. Setting., Six senior centers located in New York City. Participants., We enrolled a race/ethnicity stratified (African American, Hispanic, or non-Hispanic White) sample of 90 subjects who were ages 60 years or older and had chronic back pain. Results., While 60% of non-Hispanic Whites reported prior participation in a self-management pain program, fewer Hispanic (23%) and African Americans (20%) participants reported prior participation. Most participants (80%) were strongly willing to participate in the new program. Multivariate analyses revealed that only pain intensity had a trend toward significance (P = 0.07), with higher pain scores associated with greater willingness to participate. Few barriers to participation were identified, however, respondents felt that tailoring the course to best meet the needs of those with physical disabilities, providing flexibility in class timing, and informing individuals about program benefits prior to enrollment could help maximize program reach. No race/ethnicity differences were identified with respect to willingness to participate or program participation barriers. Conclusions., These data support efforts to disseminate self-management pain programs in older populations, particularly minority communities. The recommendations made by participants can help to guide implementation efforts of the newly developed pain program and may help to enhance both their reach and success. [source] Potential population-based electronic data sources for rapid pandemic influenza vaccine adverse event detection: a survey of health plans,PHARMACOEPIDEMIOLOGY AND DRUG SAFETY, Issue 12 2008Kristen M. Moore MPH Abstract Purpose A vaccine against pandemic influenza may be rapidly and widely distributed, and could be used in populations with little prior exposure to influenza vaccines. Under such conditions, it will be important to gain timely information about the rates of vaccine adverse events, ideally by using electronic data from large populations. Many public and private health plans and payers have such information. Methods Between May and September 2007, we conducted a decision maker interview and technical assessment with several health plans in the United States. The interview and survey evaluated technical capability, organizational capacity, and willingness to participate in a coordinated program of rapid safety research targeting pandemic and other influenza vaccines. Results Eleven health plans (eight private, three public) participated in the decision maker interview. Most interviewees were medical directors or held similar positions within their organizations. Participating plans provided coverage and/or care for approximately 150 million members in the U.S. Nine health plans completed a technical assessment survey. Most decision makers indicated interest and willingness to participate in a coordinated rapid safety surveillance program, and all reported the necessary claims data analysis experience. Respondents noted legal, procedural, budgetary, and technical barriers to participation. Conclusions Senior decision makers representing private and public health plans were willing and asserted the ability of their organizations to participate in pandemic influenza vaccine safety monitoring. Developing working relationships, negotiating contracts, and obtaining necessary regulatory and legal approvals were identified as key barriers. These findings may be generalizable to other vaccines and pharmaceutical products. Copyright © 2008 John Wiley & Sons, Ltd. [source] Native Australian frogs avoid the scent of invasive cane toadsAUSTRAL ECOLOGY, Issue 1 2009LÍGIA PIZZATTO Abstract Invasive species can affect the ecosystems they colonize by modifying the behaviour of native taxa; for example, avoidance of chemical cues from the invader may modify habitat use (shelter site selection) by native species. In laboratory trials, we show that metamorphs of most (but not all) native frog species on a tropical Australian floodplain avoid the scent of invasive cane toads (Bufo marinus Linnaeus 1758). Cane toads also avoid conspecific scent. This response might reduce vulnerability of metamorph frogs and toads to larger predatory toads. However, similar avoidance of one type of pungency control (garlic), and the presence of this avoidance behaviour in frogs at the toad invasion front (and hence, with no prior exposure to toads), suggest that this may not be an evolved toad-specific response. Instead, our data support the simpler hypothesis that the metamorph anurans tend to avoid shelter sites that contain strong and unfamiliar scents. Temporal and spatial differences in activity of frogs versus toads, plus the abundance of suitable retreat sites during the wet season (the primary time of frog activity), suggest that avoiding toad scent will have only a minor impact on the behaviour of native frogs. However, this behavioural impact may be important when environmental conditions bring toads and frogs into closer contact. [source] RSD931, a novel anti-tussive agent acting on airway sensory nervesBRITISH JOURNAL OF PHARMACOLOGY, Issue 3 2003J J Adcock The anti-tussive effects, of the local anaesthetic, lidocaine and carcainium chloride (RSD931) have been investigated in guinea-pigs and rabbits. Pre-treatment of guinea-pigs with aerosols of lidocaine or RSD931 at 0.1, 1.0 and 10 mg ml,1 reduced the number of citric acid-induced coughs by 9.3, 32.6 and 40.9% (P>0.05) for lidocaine and by 25.3% (P>0.05), 40.4% (P>0.05) and 97.6% (P<0.01) for RSD931, respectively and increased the latency to onset of cough at 10.0 mg ml,1 only. In addition, RSD931 at 10 mg ml,1 reduced citric acid-evoked cough responses in rabbits (with prior exposure to ozone at 3 p.p.m. for 1 h) from 22.1±5.1 to 2.7±0.9 coughs (P<0.01). Acute pre-treatment of guinea-pigs with aerosols of lidocaine or RSD931 at 10.0 and 30.0 mg ml,1 reduced the number of capsaicin-evoked coughs by 42.2 and 10.3% (P>0.05) (lidocaine) and by 25% (P>0.05) and 76.9% (P<0.01) (RSD931), respectively. Lidocaine had little effect on the latency of cough onset at either 10.0 or 30.0 mg ml,1, however, RSD at 30.0 mg ml,1 significantly (P<0.05) prolonged the latency of cough onset. RSD931 (10.0 mg ml,1) significantly (P<0.05,<0.01) reduced the spontaneous and histamine-evoked discharges in A,-fibres originating from airway, rapidly adapting stretch receptors (RARs) without affecting histamine-evoked bronchoconstriction. Lidocaine at 10.0 mg ml,1 also significantly (P<0.05) inhibited the spontaneous and histamine-induced discharges of RARs without affecting histamine-evoked bronchoconstriction. Aerosols of RSD931 (10.0 mg ml,1) caused a transient, but significant (P<0.05), activation of pulmonary C-fibre endings 2.5 min after administration started. RSD931 had no significant (P>0.05) effects on discharges in bronchial C-fibres originating from bronchial C-fibre endings, capsaicin-evoked discharges of either pulmonary or bronchial C-fibre endings or on capsaicin-evoked bronchoconstriction. In contrast, lidocaine (10.0 mg ml,1) significantly (P<0.05) inhibited spontaneous and capsaicin-induced discharges in both pulmonary and bronchial C-fibres respectively. Lidocaine also significantly (P<0.05) reduced capsaicin-evoked bronchoconstriction. These studies suggest that the anti-tussive actions of RSD931 are mediated via inhibition of discharges in A,-fibres originating from airway RARs. The mechanism of action of RSD931 is distinct from that of the local anaesthetic lidocaine and RSD931 may represent a novel class of anti-tussive agent. British Journal of Pharmacology (2003) 138, 407,416. doi:10.1038/sj.bjp.0705056 [source] Survival is poorer in patients with secondary core-binding factor acute myelogenous leukemia compared with de novo core-binding factor leukemiaCANCER, Issue 14 2009Gautam Borthakur MD Abstract BACKGROUND: Therapy related secondary acute myelogenous leukemia (AML) was commonly associated with prior exposure to alkylating agents or topoisomerase inhibitor. The long-term outcome of such patients with secondary AML was found to be worse than that of patients with de novo AML. Earlier reports suggested similar outcomes for patients with de novo and secondary AML associated with core-binding factor (CBF) abnormalities. METHODS: A total of 188 patients with CBF AML were analyzed. The frequency of secondary CBF AML was 9%. RESULTS: Patients with secondary CBF AML were found to have significantly worse overall (OS) and event-free survival (EFS) compared with patients with de novo CBF AML. Secondary CBF AML status appeared to have only marginal significance in multivariate analysis. CONCLUSIONS: Matched analysis (by age, Eastern Cooperative Oncology Group performance status, and additional cytogenetic abnormality) indicated worse OS and EFS in patients with secondary CBF AML. Cancer 2009. © 2009 American Cancer Society. [source] | |||||||||||||||||||||||||