46 resultados para ABSORBING STATES
Resumo:
(-)-1-(3,4-Dimethoxyphenetylamino)-3-(3,4-dihydroxy)-2-propanol [(-)-RO363] is a highly selective beta(1)-adrenergic receptor (beta(1)AR) agonist. To study the binding site of beta(1)-selective agonist, chimeric beta(1)/beta(2)ARs and Ala-substituted beta(1)ARs were constructed. Several key residues of beta(1)AR [Leu(110) and Thr(117) in transmembrane domain (TMD) 2], and Phe(359) in TMD 7] were found to be responsible for beta(1)-selective binding of (-)-RO363, as determined by competitive binding. Based on these results, we built a three-dimensional model of the binding domain for (-)-RO363. The model indicated that TMD 2 and TMD 7 of beta(1)AR form a binding pocket; the methoxyphenyl group of N-substituent of (-)-RO363 seems to locate within the cavity surrounded by Leu(110), Thr(117), and Phe(359). The amino acids Leu(110) and Phe(359) interact with the phenyl ring of (-)-RO363, whereas Thr(117) forms hydrogen bond with the methoxy group of (-)-RO363. To examine the interaction of these residues with beta(1)AR in an active state, each of the amino acids was changed to Ala in a constitutively active (CA)-beta(1)AR mutant. The degree of decrease in the affinity of CA-beta(1)AR for (-)-RO363 was essentially the same as that of wild-type beta(1)AR when mutated at Leu(110) and Thr(117). However, the affinity was decreased in Ala-substituted mutant of Phe(359) compared with that of wild-type beta(1)AR. These results indicated that Leu(110) and Thr(117) are necessary for the initial binding of (-)-RO363 with beta(1)-selectivity, and interaction of Phe(359) with the N-substituent of (-)-RO363 in an active state is stronger than in the resting state.
Resumo:
DP1, a dimerization partner protein of the transcription factor E2F, is known to inhibit Wnt/β-catenin signalling along with E2F, although the function of DP1 itself was not well characterized. Here, we present a novel dual regulatory mechanism of Wnt/β-catenin signalling by DP1 independent from E2F. DP1 negatively regulates Wnt/β-catenin signalling by inhibiting Dvl-Axin interaction and by enhancing poly-ubiquitination of β-catenin. In contrast, DP1 positively modulates the signalling upon Wnt stimulation, via increasing cytosolic β-catenin and antagonizing the kinase activity of NLK. In Xenopus embryos, DP1 exerts both positive and negative roles in Wnt/β-catenin signalling during anteroposterior neural patterning. From subcellular localization analyses, we suggest that the dual roles of DP1 in Wnt/β-catenin signalling are endowed by differential nucleocytoplasmic localizations. We propose that these dual functions of DP1 can promote and stabilize biphasic Wnt-on and Wnt-off states in response to a gradual gradient of Wnt/β-catenin signalling to determine differential cell fates.
Resumo:
Objective: To assess the importance of spirituality and religious coping among outpatients with a DSM-IV diagnosis of schizophrenia or schizoaffective disorder living in three countries. Method: A total of 276 outpatients (92 from Geneva, Switzerland, 121 from Trois-Rivières, Canada, and 63 from Durham, North Carolina), aged 18-65, were administered a semi-structured interview on the role of spirituality and religiousness in their lives and to cope with their illness. Results: Religion is important for outpatients in each of the three country sites, and religious involvement is higher than in the general population. Religion was helpful (i.e., provided a positive sense of self and positive coping with the illness) among 87% of the participants and harmful (a source of despair and suffering) among 13%. Helpful religion was associated with better social, clinical and psychological status. The opposite was observed for the harmful aspects of religion. In addition, religion sometimes conflicted with psychiatric treatment. Conclusions: These results indicate that outpatients with schizophrenia or schizoaffective disorder often use spirituality and religion to cope with their illness, basically positively, yet sometimes negatively. These results underscore the importance of clinicians taking into account the spiritual and religious lives of patients with schizophrenia.
Resumo:
Seven different electron microscopy techniques habe been employed to study the RecA protein of E. coli. This review provides a summary of the conclusions that have been drawn from these studies, and attempts to relate these observations to models for the role of RecA protein in homologous recombination.
Resumo:
Freud defined the drive as "a concept on the frontier between the mental and the somatic". Today this view that was based on clinical observations interpreted within the psychoanalytical framework, can be revisited in light of the current neuroscientific notions of neuronal plasticity and somatic states. Indeed, through the mechanisms of plasticity experience leaves a trace that forms the neural basis of a representation of the experience. Such a representation R is associated with a somatic state S in the sense taken from the "somatic marker" model of Damasio. Thus, the internal reality of the subject, particularly the unconscious one, is constituted by such connected R's and S's. In the model that we discuss, the posterior insula represents the primary interoceptive cortex where information about somatic states S converges, while in the anterior insula the connection between R and S can take place and establish a neurobiological correlate for the notion of drive. We posit that the re-representations of S associated with R in the anterior insula may correspond to the Vorstellungsrepräsentanz postulated by Freud. We further propose that the tension between R and S established in the anterior insula is discharged according to the notion of drive through the motor arm of the limbic system, namely the anterior cingulate cortex which is heavily connected with the anterior insula.
Resumo:
Based on the case of reforms aimed at integrating the provision of income protection and employment services for jobless people in Europe, this thesis seeks to understand the reasons which may prompt governments to engage in large-scale organisational reforms. Over the last 20 years, several European countries have indeed radically redesigned the organisational structure of their welfare state by merging or bundling existing front-line offices in charge of benefit payment and employment services together into 'one-stop' agencies. Whereas in academic and political debates, these reforms are generally presented as a necessary and rational response to the problems and inconsistencies induced by fragmentation in a context of the reorientation of welfare states towards labour market activation, this thesis shows that the agenda setting of these reforms is in fact the result of multidimensional political dynamics. More specifically, the main argument of this thesis is that these reforms are best understood not so such from the problems induced by organisational compartmentalism, whose political recognition is often controversial, but from the various goals that governments may simultaneously achieve by means of their adoption. This argument is tested by comparing agenda-setting processes of large-scale reforms of coordination in the United Kingdom (Jobcentre Plus), Germany (Hartz IV reform) and Denmark (2005 Jobcentre reform), and contrasting them with the Swiss case where the government has so far rejected any coordination initiative involving organisational redesign. This comparison brings to light the importance, for the rise of organisational reforms, of the possibility to couple them with the following three goals: first, goals related to the strengthening of activation policies; second, institutional goals seeking to redefine the balance of responsibilities between the central state and non-state actors, and finally electoral goals for governments eager to maintain political credibility. The decisive role of electoral goals in the three countries suggests that these reforms are less bound by partisan politics than by the particular pressures facing governments arrived in office after long periods in opposition.
Resumo:
The end-Permian mass extinction greatly diminished marine diversity and brought about a whole-scale restructuring of marine ecosystems; these ecosystem changes also profoundly affected the sedimentary record. Data presented here, attained through facies analyses of strata deposited during the immediate aftermath of the end-Permian mass extinction (southern Turkey) and at the close of the Early Triassic (southwestern United States), in combination with a literature review, show that sedimentary systems were profoundly affected by: (1) a reduction in biotic diversity and abundance and (2) long-term environmental fluctuations that resulted from the end-Permian crisis. Lower Triassic strata display widespread microbialite and carbonate seafloor fan development and contain indicators of suppressed infaunal bioturbation such as flat-pebble conglomerates and wrinkle structures (facies considered unusual in post-Cambrian subtidal deposits). Our observations suggest that depositional systems, too, respond to biotic crises, and that certain facies may act as barometers of ecologic and environmental change independent of fossil assemblage analyses. Close investigation of facies changes during other critical times in Earth history may serve as an important tool in interpreting the ecology of metazoans and their environment.