[Operationalization of the clinical head and neck examination]. / Die Operationalisierung der HNO-Spiegeluntersuchung.

Standardized procedures support learning of complex psychomotoric activities. We standardized the clinical otolaryngology examination to provide an objective basis for its operationalization. The Impact of the standardization on the objective measureable learning success and the student's evaluation were determined.During their 1-week ENT internship 166 medical students learned the standardized clinical otolaryngology examination. At the end of this week they absolved an objective structured clinical examination (OSCE). The students evaluated both, the teaching (standardization) and examination method (OSCE) with 2 questionnaires.All students passed the exam with mean score of 60.3±3.5 (max. 65) points. By using the OSCE checklist 2 independent examiners appraised nearly identical examination performances. In both evaluations the students rated the teaching and examination design positive. All students greatly appreciated the standardized clinical examinations and considered it as are very important for learning practical skills.The standardization of clinical otolaryngology examination permits objective and reliable tests for learning progress and success. Furthermore transparency, process reliability and test quality are considerably improved. The student's evaluation clearly reflects the mentioned advantages.

Efficient and fast targeted production of murine models based on ENU mutagenesis.

Mice with targeted genetic alterations are the most effective tools for deciphering organismal gene function. We generated an ENU-based parallel C3HeB/FeJ sperm and DNA archive characterized by a high probability to identify allelic variants of target genes as well as high efficiencies in allele retrieval and model revitalization. Our archive size of over 17,000 samples contains approximately 340,000 independent alleles (20 functional mutations per individual sample). Based on an estimated number of approximately 30,000 mouse genes, the parallel sperm/DNA archive should permit the identification and recovery of ten or more alleles per average target gene which translates to a calculated 99% success rate in the discovery of five allelic variants for any given average gene. The low rate of unrelated ENU-induced passenger mutations has no practical impact on the analysis of the allele-specific phenotype at the G3 generation because of dilution and free segregation of such unrelated passenger mutations. To date 39 mouse models representing 33 different genes have been recovered from our archive using in vitro fertilization techniques. The generation time for a murine model heterozygous for a mutation in a gene of interest is less than 2 months, i.e., three to four times faster compared with current embryonic stem-cell-based technologies. We conclude that ENU-based targeted mutagenesis is a powerful tool for the fast and high-throughput production of murine gene-specific models for biomedical research.