Athymic nude rat. III natural cell mediated cytotoxicity.

Homozygous rnu/rnu and heterozygous +/rnu rats were investigated and compared with each other for the existence of natural cell-mediated cytotoxicity. Investigated were total, adherent, and nonadherent cell populations from spleen, peritoneal cavity, and mesenteric lymph node. The natural killer (NK) cell activity was measured in a 4-hr 51Cr-release assay with a xenogeneic murine YAC lymphoma target cell line. In both and +/rnu rats the peritoneal cavity had the highest percentage of activity, while the spleen and mesenteric lymph node showed a lower activity. The mesenteric lymph node of +/rnu rats of 8–10 weeks of age was found to express a very low activity, in contrast to a very high activity in rats. For almost every effector to target cell (E:T) ratio investigated (100, 70, 50, and 10), the natural killer cell activity in the nude rats was found to be significantly higher than in their thymus-bearing littermates. In comparison with that of +/rnu rats, NK activity in the nonadherent cell fractions of athymic rats was 50 to 60% higher in spleen cells, doubled in peritoneal cells, and increased 10-fold or higher in lymph node cells. Investigations o

Towards fair and effective North-South collaboration: Realising a programme for demand-driven and locally led research

textabstractBackground: At the turn of the 90s, studies showed that health research contributed little to health and development in low- and middle-income countries because it was oriented towards international priorities and dominated by researchers from the North. A new approach to North-South collaboration was required that would support demand-driven and locally led research in the South. The aim of this study was to analyse the development and functioning of a programme for demand-driven and locally led research in Ghana that was supported by a North-South collaboration. Methods: For this mixed-method case study, we combined document analysis, key informant interviews and observation of programme events. Results: The development of the research programme started with constructing a sponsorship constellation in the Netherlands. After highlighting the problems with traditional research collaboration, an advisory council formulated a vision for a more equal and effective approach to North-South collaboration. Together with Ghanaian partners, this vision was turned into a proposal for a Ghanaian-led programme for demand-driven and locally led research, which was funded by the Netherlands government. Research priority setting showed that the Ghanaian research needs were very different from the priorities of foreign funders and researchers. After a slow start, the number of locally submitted proposals increased from 13 in 2001 to 94 in 2005, revealing the existence of a substantial, but partly latent reservoir of research capacity. In total, 79 studies were funded. An impact evaluation showed that the results of the majority of the studies were used to contribute to action. Despite its success, the research programme came to an end in 2008 after the sponsorship constellation in the Netherlands fell apart. Conclusion: Our study shows that realising a programme for demand-driven and locally led research in the South provides an effective approach to North-South collaboration in which results are used and local capacities and institutions are strengthened