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Stimuli Used (stimulus + used)
Selected AbstractsChanges in reactivity of rat arteries subjected to dynamic stretchACTA PHYSIOLOGICA, Issue 1 2000Dvoretsky The effect of dynamic stretch on the reactivity of the rat tail and mesenteric artery segments was studied. Segments mounted on a myograph were stretched by a computer-controlled motorized micromanipulator. Dynamic stretch (1, 5 or 7 Hz) inhibited the artery constriction induced by noradrenaline (10 ,M), 5-hydroxytryptamine (0.7 ,M), or electrical field stimulation of intramural nerves. In contrast, dynamic stretch enhanced the tetrodotoxin-insensitive dilation induced by electrical field stimulation of noradrenaline-contracted arteries. Maximal increase of dilation evoked by electrical field stimulation (24.5 ± 5.0% in mesenteric and 50.3 ± 15.6% in the tail artery) was observed at a dynamic stretch-frequency of 5 Hz. An inhibitor of nitric oxide synthesis, NG -nitro- L -arginine (100 ,M), abolished the difference in reactivity between static and dynamic conditions. The results indicate that dynamic stretch of the arteries activates nitric oxide synthesis/secretion, thus reducing constrictor and increasing dilator responses to the stimuli used. [source] Attentional re-training decreases attentional bias in heavy drinkers without generalizationADDICTION, Issue 3 2007Tim Schoenmakers ABSTRACT Aims To examine whether alcohol-related attentional bias (AB) can be reduced by training heavy drinkers to attend to soft drinks as an alternative to alcohol. Diminishing AB is important because AB has been suggested to be a significant factor in the development, maintenance and relapse of addictive behaviours. AB was trained in a clinically relevant design, and we studied the generalization of this training. Design, participants and intervention We assigned randomly 106 heavy drinking male college and university students to the attentional re-training (AR; modified visual-probe task) or control condition (standard visual-probe task). Setting Laboratory at Maastricht University. Measurements We measured the effects of AR on the visual-probe task with stimuli that were presented in the AR and with new stimuli, and on an alternative measure of AB, the flicker paradigm. We further measured effects on craving and preference for either an alcohol beverage or a soft drink. Findings After AR, participants had learned to avoid alcohol stimuli and had developed an AB for soft drinks. This effect was restricted to stimuli used in the AR. The flicker task, where AB for alcohol was found in both the AR and control groups, was not affected by the AR. No effect was found on craving and the preference task. Conclusions Although heavy drinkers can learn to attend selectively to an alternative category for alcohol, a single AR is not sufficient to decrease symptoms of problem drinking. [source] Age Recognition in Adults with Intellectual Disabilities: a Literature Review and an Exploratory StudyJOURNAL OF APPLIED RESEARCH IN INTELLECTUAL DISABILITIES, Issue 3 2000Dorothy M. Bell The ability of children to classify accurately their own ages and the ages of others has been the subject of very limited research. However, the literature is largely in agreement on there being progressive increases in skill with chronological age, although there is disagreement on the age at which this ability becomes well developed. The processes look similar in the field of intellectual disabilities, although this area is extremely under-researched. Key factors may include age, the amount of time spent in institutions (e.g. long-term hospitals for people with intellectual disabilities), developmental level and IQ. The present paper provides a review of the relevant literature and an exploratory study investigating the age recognition of self and colleagues in a group of 20 adults with intellectual disability, some from within what has been a major hospital for people with intellectual disabilities and some from the wider community. Measures of age recognition using photographs, as well as standardized measures of intellectual ability and social adaptive behaviour, were administered, and correlations were found between the ability to recognize age in others and developmental age, and also IQ. Success on the task of age discrimination appears to be more likely if the IQ of the individual is around 60,65 or above, and if the person shows social adaptive behaviour equivalent to 8 or 9 years of age and over. Also included in the study was a task in which only the discrimination of whether the photographs were of adults or children was required, and this proved to be a simpler process for the participants. The present study also demonstrates some of the discriminative stimuli used by adults with intellectual disabilities to ascertain the approximate age of a person. [source] Cautious response of inexperienced birds to conventional signal of stronger threatJOURNAL OF AVIAN BIOLOGY, Issue 6 2007Tomasz S. Osiejuk Several studies demonstrated that bird song functions as a first line of territorial defence. The efficiency of deterring rivals depends strongly on the strategy of singing used (e.g. alternating/overlapping singing, singing with low/high rate, matching song type of a rival or singing different type). Causes of between males variation during countersinging are still not fully understood, especially when different signals have similar production costs and their meaning is assigned by arbitrary convention (conventional signalling). We tested whether an oscine bird with small repertoire size, the ortolan bunting Emberiza hortulana, differentiate strategy of responding to song of an intruder in relation to its age and threat value of signals. We performed playback experiments to measure response of second year (SY) and after second year (ASY) males to a song of low (eventual variety singing) and high (immediate variety singing) threat value. We found substantial differences in response to playback, which were related both to the type of stimuli used and age of responding males. Both SY and ASY males gave more calls than songs in response to immediate variety playback, which suggest stronger vocal response to the signal of higher threat value. Approaching loudspeaker was similar for both age classes when lower threat value signal was played back, while simultaneously SY males clearly avoided approaching loudspeaker when stronger threat values signal was played back. We conclude that ortolan bunting differentiate response to signal of different threat value and that the strength of response depends on the age of a male. This study provides experimental evidence that age of receiver affects its response to a territorial intruder. It also demonstrates that observed in many studies variation in response to playback may be an effect of age differences between males, which rarely is controlled. [source] Identification of distinct and common gene expression changes after oxidative stress and gamma and ultraviolet radiation,MOLECULAR CARCINOGENESIS, Issue 2 2003Alexandra N. Heinloth Abstract The human genome is exposed to many different kinds of DNA-damaging agents. While most damage is detected and repaired through complex damage recognition and repair machineries, some damage has the potential to escape these mechanisms. Unrepaired DNA damage can give rise to alterations and mutations in the genome in an individual cell, which can result in malignant transformation, especially when critical genes are deregulated. In this study, we investigated gene expression changes in response to oxidative stress, gamma (,) radiation, and ultraviolet (UV) radiation and their potential implications in cancer development. Doses were selected for each of the three treatments, based on their ability to cause a similar G1 checkpoint induction and slow down in early S-phase progression, as reflected by a comparable reduction in cyclin E,associated kinase activity of at least 75% in logarithmically growing human dermal diploid fibroblasts. To investigate gene expression changes, logarithmically growing dermal diploid fibroblasts were exposed to either , radiation (5 Gy), oxidative stress (75 ,M of tert-butyl hydroperoxide (t -butyl-OOH)), or UV radiation (UVC) (7.5 J/m2) and RNA was harvested 6 h after treatment. Gene expression was analyzed using the NIEHS Human ToxChip 2.0 with approximately 1901 cDNA clones representing known genes and expressed sequence tags (ESTs). We were able to identify common and distinct responses in dermal diploid fibroblasts to the three different stimuli used. Within our analysis, gene expression profiles in response to , radiation and oxidative stress appeared to be more similar than profiles expressed after UV radiation. Interestingly, equivalent cyclin E,associated kinase activity reduction with all the three treatments was associated with greater transcriptional changes after UV radiation than after , radiation and oxidative stress. While samples treated with UV radiation displayed modulations of their mitogen activated protein kinase (MAPK) pathway, , radiation had its major influence on cell-cycle progression in S-phase and mitosis. In addition, cell cultures from different individuals displayed significant differences in their gene expression responses to DNA damage. Published 2003 Wiley-Liss, Inc. [source] Into the twilight zone: the complexities of mesopic vision and luminous efficiencyOPHTHALMIC AND PHYSIOLOGICAL OPTICS, Issue 3 2006Andrew Stockman Abstract Of all the functions that define visual performance, the mesopic luminous efficiency function is probably the most complex and hardest to standardise or model. Complexities arise because of the substantial and often rapid visual changes that accompany the transition from scotopic to photopic vision. These are caused not only by the switch from rod to cone photoreceptors, but also by switches between different post-receptoral pathways through which the rod and cone signals are transmitted. In this review, we list several of the complexities of mesopic vision, such as rod,cone interactions, rod saturation, mixed photoreceptor spectral sensitivities, different rod and cone retinal distributions, and the changes in the spatial properties of the visual system as it changes from rod- to cone-mediated. Our main focus, however, is the enormous and often neglected temporal changes that occur in the mesopic range and their effect on luminous efficiency. Even before the transition from rod to cone vision is complete, a transition occurs within the rod system itself from a sluggish, sensitive post-receptoral pathway to a faster, less sensitive pathway. As a consequence of these complexities, any measure of mesopic performance will depend not only on the illumination level, but also on the spectral content of the stimuli used to probe performance, their retinal location, their spatial frequency content, and their temporal frequency content. All these should be considered when attempting to derive (or to apply) a luminous efficiency function for mesopic vision. [source] Minocycline exerts inhibitory effects on multiple mitogen-activated protein kinases and I,B, degradation in a stimulus-specific manner in microgliaJOURNAL OF NEUROCHEMISTRY, Issue 2 2006Maria Nikodemova Abstract CNS inflammation mediated by microglial activation can result in neuronal and glial cell death in a variety of neurodegenerative and demyelinating diseases. Minocycline, a second-generation tetracycline, has profound anti-inflammatory properties in the CNS mediated, in part, by inhibition of microglia. MAPK and nuclear factor-,B (NF-,B) activation are hallmarks of activated microglia and they are critical for the expression of many inflammatory mediators. In the present study, we investigated minocycline effects on activation of p38, c-Jun-N-terminal activated protein kinase (JNK) 1/2 and extracellular signal regulated kinase (ERK) 1/2 MAPKs and inhibitor , of NF-,B (I,B,) degradation in BV-2 and primary microglial cells. Our results demonstrate that minocycline has the ability to inhibit all MAPKs but these effects strongly depend on the stimulus used for MAPK activation. Minocycline significantly decreased activation of all lipopolysaccharide-stimulated MAPKs but it was without effect on MAPKs activated by H2O2. Minocycline inhibited JNK1/2 and ERK1/2 but not p38 when stimulated by 2,,3,- O -(4-benzoylbenzoyl)-adenosine 5,-triphosphate, indicating that minocycline affects only certain upstream signaling target(s) that are stimulus-specific. Our data also suggest that protein kinase C (PKC) inhibition may be partially involved in the minocycline mechanism of MAPK inhibition. In addition, minocycline attenuated lipopolysaccharide-stimulated degradation of I,B, implying a possible inhibitory role on NF-,B transcriptional activity. [source] | |||||||||||||