Biomedical subjects

K Rothermund

Publications and source records attributed to K Rothermund.

8 recordsLinked to original sources

PubMed2001

Suppression of apoptosis and granulocyte colony-stimulating factor-induced differentiation by an oncogenic form of Cbl.

OBJECTIVE: The retroviral oncogene v-Cbl causes pre-B cell lymphomas and myeloid leukemias in mice, and its Drosophila homologue is oncogenic, causing enhanced receptor tyrosine kinase signaling. The human Cbl gene resides at 11q23. The aim of this study is to determine the effect of oncogenic Cbl on growth-regulating responses. MATERIALS AND METHODS: The oncogenic mutant of Cbl (CblDelta1-357) was transfected into factor-dependent 32Dcl3 myeloid cells. Consequently, cell survival and differentiation were measured. Lyn, Syk, MAP kinase, and phosphatidylinositol 3'(PI3')-kinase activities, protein phosphorylation, Bcl-2 promoter activity, ubiquitination, and levels of Bcl-2, Bax, Bad, and Bcl-x(L) were determined. In addition, the effect of v-Cbl on TF-1 cell survival upon granulocyte-macrophage colony-stimulating factor withdrawal was studied. RESULTS: 32Dcl3 and TF-1 cells expressing v-Cbl showed resistance to apoptosis upon growth factor withdrawal, and 32Dcl3 cells completely failed to respond to granulocyte colony-stimulating factor's induction of differentiation. Basal activities of Lyn, Syk, and PI3'-kinase were elevated in the v-Cbl line. There was neither enhanced tyrosine phosphorylation of cellular protein content, Cbl, or Jak2, nor serine phosphorylation of MAP kinase or Akt. After factor withdrawal, the level of Bcl-2 was greater in v-Cbl cells than in control cells. CONCLUSIONS: Neither increased Bcl-2 promoter activity nor decreased ubiquitination of Bcl-2 could account for increased Bcl-2 levels. v-Cbl-expressing 32Dcl3 cells were resistant to differentiation. v-Cbl suppresses apoptosis and differentiation, possibly through enhancement of Lyn, Syk, and PI3'-kinase activities and Bcl-2.

Animals↗

PubMed2001

Figure-ground asymmetries in the Implicit Association Test (IAT).

Based on the assumption that binary classification tasks are often processed asymmetrically (figure-ground asymmetries), two experiments showed that association alone cannot account for effects observed in the Implicit Association Test (IAT). Experiment 1 (N = 16) replicated a standard version of the IAT effect using old vs. young names as target categories and good and bad words as attribute categories. However, reliable compatibility effects were also found for a modified version of the task in which neutral words vs. nonwords instead of good vs. bad words were used as attribute categories. In Experiment 2 (N = 8), a reversed IAT effect was observed after the figure-ground asymmetry in the target dimension had been inverted by a previous go/nogo detection task in which participants searched for exemplars of the category "young." The experiments support the hypothesis that figure-ground asymmetries produce compatibility effects in the IAT and suggest that IAT effects do not rely exclusively on evaluative associations between the target and attribute categories.

Adult↗

PubMed2001

Stimulus-feature specific negative priming.

We report the results of two experiments that showed that the time needed to respond to a feature of a stimulus increases when that particular feature of that particular stimulus previously had to be ignored. The data of Experiment 2 argue against the hypothesis that the observed stimulus-feature specific negative priming was due to a response conflict instigated by automatic episodic retrieval of prime responses. Experiment 2 also showed that the effects were not caused by difficulties in switching between prime and probe tasks and provided additional evidence for the fact that priming effects were stimulus-feature specific. The present results suggest that the selective inhibition or episodic encoding mechanisms that are assumed to underlie negative priming can operate in a more specific and powerful manner than has been previously assumed.

Adult↗

PubMed2000

Automatic vigilance: the attention-grabbing power of approach- and avoidance-related social information.

The automatic processing of information was investigated, varying valence (positive vs. negative) and relevance (other-relevant traits [ORT] vs. possessor-relevant traits [PRT]; G. Peeters, 1983) of stimuli. ORTs denote unconditionally positive or negative consequences for persons in the social environment of the holder of the trait (e.g., honest, brutal) whereas PRTs denote unconditionally positive or negative consequences for the trait holder (e.g., happy, depressive). In 2 experiments using the Stroop paradigm, larger interference effects were found for ORTs than PRTs. This is due to the behavior-relatedness of ORTs. In a go/no-go lexical decision task (Experiment 3), participants either had to withdraw their finger from a pressed key (i.e., "avoid") or had to press a key (i.e., "approach") if a word was presented. Responses to negative ORTs were relatively faster in the withdraw condition, whereas positive ORTs were relatively faster in the press condition.

Adult↗

PubMed1998

[A fair test of the spreading activation hypothesis: a study of affective congruency effects in the Stroop test].

It is argued that the Stroop color-naming task is especially suited to investigate affective priming effects in the sense of an automatic spreading of activation to other concepts of the same valence, because (a) the Stroop task is not prone to an explanation of affective congruency effects on the basis of reaction priming or reaction interference, and (b) it is possible to detect specific (fast and efficient stimulus processing due to heightened accessibility) as well as nonspecific (cognitive interference, triggering of global action tendencies) effects of an activation of valenced concepts in the Stroop task. Two experiments were conducted to investigate associative and affective priming effects with the Stroop task. In a first experiment (N = 36, SOA = 300 ms) a standard priming procedure was chosen; the primes were presented without any processing instructions. In a second experiment (N = 48, SOA = 500ms) the primes had to be reproduced after naming the color of the target. In both experiments significant association effects were found for the associative material. For the valenced material no affective congruency effects were found in either experiment. The present results are not compatible with the hypothesis of an automatic affective spreading of activation that was given as an explanation of affective congruency effects in previous studies using different tasks.

Adult↗

PubMed1995

[Experimental analysis of processing stressful information: differential and age-related psychological aspects].

In two experimental studies with older subjects, the differential accessibility of palliative interpretations of negative situations was investigated using a scenario paradigm. Short episodes (formulated in a self-referent manner) were presented on a CRT-screen. Each story contained a palliative and distressing interpretation of a negative life situation. In a recognition test, the reaction time and the error variable were used as an index of accessibility of those aspects. In a pilot study (N = 62; age of subjects 49-79 years), it was found that the dispositional tendency to reinterpret negative life situations flexibly correlates positively with the accessibility of palliative information. Using a priming approach in the main study, it was shown that this result is based on a differential moderated association of the negative life-event and the type of information (i.e., palliative or distressing) (N = 120; age of subjects: 56-80 years). Especially with respect to scenarios which are centered on age-related declines, results were more pronounced with increasing age. The results are discussed in terms of a theory which contrasts active-instrumental efforts of coping with accommodative mechanisms of adjustment and reinterpretation.

Adaptation, Psychological↗

PubMed1994

Self-percepts of control in middle and later adulthood: buffering losses by rescaling goals.

The authors propose a model of how a sense of control is maintained in later adulthood through shifts in the subjective importance of developmental goals. Developmental goals and control beliefs were repeatedly assessed over an 8-year interval on a core sample of 735 participants (initial age range: 30-59 years). The findings reveal a high degree of stability in generalized perceptions of control even in the transition to later adulthood. In line with predictions, moderated multiple regressions indicated(a) that the degree to which self-percepts of control within a particular goal domain affect an individual's general sense of control depends on the personal importance of that domain, and (b) that losses of control within a goal domain affect general perceptions of control to a lesser degree if the importance of the respective domain is downscaled within the same longitudinal interval. Implications for theories of depression as well as for successful aging are discussed.

Adaptation, Psychological↗

PubMed1992

[125I]thienylphencyclidine, a novel ligand for the NMDA receptor.

We have monitored the binding of [125I]thienylphencyclidine ([125I]TCP), a novel high affinity radioiodinated ligand that specifically recognizes the NMDA (N-methyl-D-aspartate) receptor in rat brain membranes. [125I]TCP binds with an affinity of about 30 nM, and recognizes a similar number of binding sites to previously employed ligands for this receptor. [125I]TCP binding is characterized by slow association and dissociation rates, and the latter can be modified by the addition of Mg2+ or Zn2+, as previously described for [3H]dizocilpine ([3H]MK801). Other phencyclidine-like ligands displaced [125I]TCP binding with the order of potency dizocilpine greater than thienylphencyclidine greater than ITCP greater than phencyclidine greater than ketamine. The binding of [125I]TCP was also increased by NMDA and glycine-site agonists and inhibited by antagonists of these sites. Surprisingly, however, the polyamines spermidine and spermine did not increase [125I]TCP, even though the polyamine antagonist arcaine was an effective inhibitor of binding. These results show that [125I]TCP is a useful ligand for the NMDA receptor complex that binds to the receptor in a manner that is qualitatively distinct from previously described ligands.

Animals↗