Term and role of tumor centres in oncology healthcare in Germany.

Breast cancer is the most common malignant disease among women in Germany. There are more than 50,000 new cases of breast cancer diagnosed each year in the country. As breast cancer is a complex disease it necessitates an interdisciplinary treatment, therefore it is very likely that patients with breast cancer will benefit from treatment in special centers, either a "breast cancer centre" or "tumor centre". In recent years certifying programs for the above mentioned centers have been introduced, which guarantee standards of the quality of treatment for breast cancer all over the country. In this article we report on the development and role of tumor centers in oncology healthcare in Germany, which nowadays have a very good international reputation. Moreover, they may be a good example to other countries to found similar centers in order to improve standards of the management in oncology healthcare.

Assembly of NADH: ubiquinone reductase (complex I) in Neurospora mitochondria. Independent pathways of nuclear-encoded and mitochondrially encoded subunits.

NADH:ubiquinone reductase, the respiratory chain complex I of mitochondria, consists of some 25 nuclear-encoded and seven mitochondrially encoded subunits, and contains as redox groups one FMN, probably one internal ubiquinone and at least four iron-sulphur clusters. We are studying the assembly of the enzyme in Neurospora crassa. The flux of radioactivity in cells that were pulse-labelled with [35S]methionine was followed through immunoprecipitable assembly intermediates into the holoenzyme. Labelled polypeptides were observed to accumulate transiently in a Mr 350,000 intermediate complex. This complex contains all mitochondrially encoded subunits of the enzyme as well as subunits encoded in the nucleus that have no homologous counterparts in a small, merely nuclear-encoded form of the NADH:ubiquinone reductase made by Neurospora crassa cells poisoned with chloramphenicol. With regard to their subunit compositions, the assembly intermediate and small NADH:ubiquinone reductase complement each other almost perfectly to give the subunit composition of the large complex I. These results suggest that two pathways exist in the assembly of complex I that independently lead to the preassembly of two major parts, which subsequently join to form the complex. One preassembled part is related to the small form of NADH:ubiquinone reductase and contributes most of the nuclear-encoded subunits, FMN, three iron-sulphur clusters and the site for the internal ubiquinone. The other part is the assembly intermediate and contributes all mitochondrially encoded subunits, one iron-sulphur cluster and the catalytic site for the substrate ubiquinone. We discuss the results with regard to the evolution of the electron pathway through complex I.