Biomedical subjects
Publications and source records attributed to Axel Kretschmer.
Novel heterocycle-fused thyromimetics are presented carrying indoles or indazoles instead of the phenolic group in T3. Potent agonists were identified in both series. SAR trends are examined and found to be mostly consistent with previously published thyromimetics. Moderate THRbeta selectivity (approx. 10-fold) was observed in the indole series using isoform-selective transient THR transfection assays.
A replication competent foamy virus derived retroviral vector expressing suicide genes has been constructed and characterized in vitro. Here we used vectors expressing the purine nucleoside phosphorylase (FOV-7/pnp), the nitroreductase (FOV-7/ntr), or the thymidine kinase (FOV-7/tk) suicide gene in an in vivo athymic (nude) mice/human glioblastoma tumor model. Gliomas were induced by subcutanous injection of U87 tumor cells. The virus vector was injected when the tumor became visible. Mice with vector virus-injected tumors were treated with the respective prodrug. The treatment resulted in significant inhibition of tumor growth. Surprisingly, in mice with vector virus-injected tumors without prodrug treatment a similar suppression of tumor growth was observed. In 65% (pnp vector), 75% (ntr vector) and 37% (tk vector) of these mice the tumors stopped growing or vanished and the animals remained tumor free for the 25 weeks of the experiment, whereas all mice of the control groups had to be killed because of the tumor growth. In control experiments, the suppression of tumor growth could also be observed when wild-type foamy virus was injected instead of the suicide gene-transducing vectors. Similar results were obtained using the nude mice/G59 human glioblastoma tumor model. In conclusion, the experiments demonstrate an oncolytic activity of foamy virus replication in a nude-mice glioblastoma xenograft tumor model. The analysis of vector virus DNA by PCR revealed that the vector persisted in different organs of the animals irrespective of the use of a prodrug or the elimination of a tumor.
We have applied several 1H solid state NMR techniques to obtain structural information on industrial silicone copolymers as thermoplastic elastomers that proved difficult to be analysed by conventional techniques. Static measurements were applied to achieve the separation between mobile and rigid parts. To get structural information fast magic angle spinning at 25 kHz in combination with a high field of 700 MHz was used. 1H spin diffusion was applied to determine the domain sizes of the micro phase-separated polymer components.