The true picture of a lake or reservoir fish stock: a review of needs and progress

The conference ‘Fish Stock Assessment Methods for Lakes and Reservoirs: Towards the True Picture of Fish Stock’ (FSAMLR) was held in September 2007 in Ceske Budejovice, Czech Republic. A total of 110 participants from 34 countries attended the meeting and 93 lectures were presented. Great advances were reported in fish surveys using hydroacoustics and multimesh gillnet techniques, with nearly 60% of all presentations dealing with these topics. In contrast, the use of other active sampling gear, especially trawling and purse seining, received relatively little attention and still requires substantial further development. Reviews of standardization of fish sampling in the European Union, Russia and North America were also presented and clearly showed the benefits of standardized procedures. A number of contributions emphasized the need to use a combination of several methods for the same habitat. A true picture of the fish stock includes knowledge of the abundance, biomass, number of species, size and age compositions. Obtaining results of assured quality for all important lake and reservoir habitats and time periods still presents a significant challenge, although good progress is being made towards this important objective

Contemporary murine models in preclinical astrocytoma drug development

Despite 6 decades of research, only 3 drugs have been approved for astrocytomas, the most common malignant primary brain tumors. However, clinical drug development is accelerating with the transition from empirical, cytotoxic therapy to precision, targeted medicine. Preclinical animal model studies are critical for prioritizing drug candidates for clinical development and, ultimately, for their regulatory approval. For decades, only murine models with established tumor cell lines were available for such studies. However, these poorly represent the genomic and biological properties of human astrocytomas, and their preclinical use fails to accurately predict efficacy in clinical trials. Newer models developed over the last 2 decades, including patient-derived xenografts, genetically engineered mice, and genetically engineered cells purified from human brains, more faithfully phenocopy the genomics and biology of human astrocytomas. Harnessing the unique benefits of these models will be required to identify drug targets, define combination therapies that circumvent inherent and acquired resistance mechanisms, and develop molecular biomarkers predictive of drug response and resistance. With increasing recognition of the molecular heterogeneity of astrocytomas, employing multiple, contemporary models in preclinical drug studies promises to increase the efficiency of drug development for specific, molecularly defined subsets of tumors