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S Eckardt

Publications and source records attributed to S Eckardt.

4 recordsLinked to original sources

[Personal contextual factors, part I].

The International Classification of Functioning, Disability and Health (ICF) does not yet classify personal contextual factors. To determine the interaction of these factors on activities and participation of a person as well as their influence on the probable outcome of interventions, they must be taken into account in individual sociomedical expertises. Therefore, a group of medical experts working for the social health insurance medical advisory boards in Germany compiled a proposal for a systematic classification of personal contextual factors into domains, categories and items with respect to the ethical guidelines of the ICF. In a second step the main issues were transferred into the preliminary draft for a short version which will be published later to give support for practical daily use in health insurance matters.

Persons with Disabilities↗

Implications of RNA structure on the annealing of a potent antisense RNA directed against the human immunodeficiency virus type 1.

Antisense RNA-mediated regulation in bacterial systems is related to the kinetics of RNA-RNA annealing in vitro. Here, we investigated the secondary structure of alphaY69, an effective HIV-directed antisense RNA in human cells. Purified RNA preparations contain a single conformer. The global structure was identified by a cleavage experiment under native conditions using a short complementary oligonucleotide and RNase H. Structural analyses indicate a three-domain structure of alphaY69 consisting of two stem-loop elements connected by a seven-nucleotide single-stranded hinge region. Kinetic data suggest that the formation of base pairs between a CGC triplet of alphaY69 and its target RNA is essential for fast annealing. The complementary sequence stretch of the target folds into a high-energy secondary structure. The relationship between modifications in structural elements of alphaY69 and the annealing kinetics suggested that rate-limiting steps of the annealing involve a single site of alphaY69 and do not involve its 5' or 3'-end. Further, the data indicate that both initial base-specific interactions and duplex formation are dependent on the CGC triplet of the central region of alphaY69. This mechanism represents a specific and efficient way of RNA-RNA annealing that is initiated by the interaction of unstructured RNA regions.

Anti-HIV Agents↗

NMDA receptor channels: subunit-specific potentiation by reducing agents.

Sulfhydryl redox agents affect NMDA receptor activity. We investigated a putative redox site in four recombinant NMDA receptors. In 293 cells expressing NR1-NR2A channels dithiothreitol (DTT) rapidly potentiated L-glutamate-activated whole-cell currents and decreased the time course of desensitization and deactivation. Part of the current potentiation (reversible component) and all kinetic changes reversed upon washout. The remaining potentiation (persistent component) was abolished by an oxidizing agent. The N-terminal 370 residues of NR2A mediate the reversible component in chimeric NR2 subunits. In cells expressing the NR1-NR2B, -NR2C, and -NR2D channels DTT elicited only a slowly developing, persistent potentiation and increased the deactivation time course. In these, but not in NR1-NR2A, the DTT effect was rendered insensitive to reoxidation by alkylation. Reduced glutathione mimicked the DTT effects only in the NR1-NR2A receptor. Hence, molecularly distinct NMDA receptors differ profoundly in their responses to sulfhydryl redox agents.

Alanine↗