Arrest patterns of circulating lymphosarcoma cells in tumour-bearing mice as modified by previously injected cell suspensions.

The effects were determined of an initial i.v. injection of 0.2 ml suspensions of 125IUdR-labelled lymphosarcoma cells on the early arrest patterns of a second injection of cancer cells into tumour-bearing mice. The results indicate that interactions between the first injection and the host markedly affected the arrest pattern of the second dose in the lungs, but not the livers, of tumour-bearing animals. These observations are explained on the basis of the injected fluid volumes, which are considerable in mice, in relation to their total blood volumes of approximately 2 ml

The UK risk assessment scheme for all non-native species

1. A pest risk assessment scheme, adapted from the EPPO (European and Mediterranean Plant Protection Organisation) scheme, was developed to assess the risks posed to UK species, habitats and ecosystems by non-native taxa. 2. The scheme provides a structured framework for evaluating the potential for non-native organisms, whether intentional or unintentional introductions, to enter, establish, spread and cause significant impacts in all or part of the UK. Specialist modules permit the relative importance of entry pathways, the vulnerability of receptors and the consequences of policies to be assessed and appropriate risk management options to be selected. Spreadsheets for summarising the level of risk and uncertainty, invasive attributes and economic impact were created. In addition, new methods for quantifying economic impact and summarising risk and uncertainty were explored. 3. Although designed for the UK, the scheme can readily be applied elsewhere