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Biomedical subjects

U Knopf

Publications and source records attributed to U Knopf.

5 recordsLinked to original sources

Duloxetine treatment of major depressive episodes in the course of psychotic disorders.

During the course of psychotic disorders, patients often suffer from intercurrent major depressive episodes (MDEs), and suicides frequently occur. This constellation challenges further improvements in psychopharmacological therapy. The antidepressant duloxetine was recently introduced as a novel reuptake inhibitor of serotonin and noradrenaline. We provide the first reports on duloxetine treatment of MDEs in the course of psychotic disorders. In two cases this substance was successfully involved as an add-on to antipsychotic treatment consisting of clozapine or amisulpride. We achieved a response of the MDEs, as reflected by psychopathological rating scales. A significant rise in the clozapine serum level was detected, most likely because of pharmacokinetic interactions. Overall, the application of duloxetine was well tolerated; therefore, further investigations in prospective studies seem to be recommendable.

Adult↗

[Paroxetine augmentation with risperidone in therapy-resistant depression].

In a 71 years-old patient, a severe therapy-resistant depressive episode without psychotic symptoms was successfully treated by a combination of paroxetine and risperidone. Previously, several different antidepressants were not effective in ameliorating the depressive symptoms which occurred repeatedly over a period of more than ten years.

Aged↗

Induction of interleukin-6 by depolarization of neurons.

Interleukin-6 (IL-6) has neuromodulatory and neuroprotective effects in vivo. It is expressed in glial cells and neurons both under physiological conditions and in various neurological diseases. Although the expression of IL-6 in glia has been intensely investigated, little is known about the regulation of IL-6 production by neurons. Therefore, we investigated the regulation of IL-6 expression in neurons. Membrane depolarization raised IL-6 mRNA accumulation in primary cortical cells and the PC-12 cell line. In vivo, IL-6 mRNA in the brain increased significantly after epileptic seizures. To investigate IL-6 gene transcription, PC-12 cells were transfected with reporter gene constructs containing the human IL-6 promoter. Membrane depolarization raised IL-6 transcription twofold to fourfold. This increase could be blocked by lowering extracellular Ca(2+) levels or by inhibiting L-type Ca(2+) channels or Ca(2+)/calmodulin-dependent protein kinases. Internal mutations in various elements of the IL-6 promoter revealed the glucocorticoid response element (GRE) 2 to be a depolarization-responsive element. Although the GRE2 bound the glucocorticoid receptor (GR) and was stimulated by dexamethasone, the GR was not responsible for the effect of membrane depolarization because a consensus GRE did not mediate stimulation by membrane depolarization. Instead, another yet undefined factor that binds to the IL-6 GRE2 may mediate the response to membrane depolarization. These data demonstrate that the expression of IL-6 in neurons is regulated by membrane depolarization and suggest a novel Ca(2+)-responsive promoter element. Through this mechanism, IL-6 may function as a neuromodulator induced by neuronal activity.

Animals↗

[Mechanical study of potential ceramic implant materials for minimal invasive anterior lumbar interbody fusion].

While autologous bone grafts are highly suitable for use in spinal arthrodesis, their use is also associated with problems (traumatization, complications). Ceramic bone substitute materials provide an attractive alternative for lumbar interbody spinal fusion. The aim of the present study was to investigate the mechanical properties of various types of ceramic using a specific fusion method. Ten specimens each of 7 different types of ceramic were tested using a hydraulic testing machine with two different sample holders: polyurethane foam (mechanical properties similar to cancellous bone) and aluminium. The parameters axial compression and axial torque were investigated. With the polyurethane foam holders, none of the ceramic implants failed under compression, while under axial rotation, two types of ceramic failed. With the aluminium holders, 3 ceramics showed no failure up to 25 kN under compression, while under torsion all the ceramics failed. One type of ceramic showed specific fracture properties with a higher load-bearing capacity after failure in comparison with all the other types studied.

Biomechanical Phenomena↗