Quantifying the relationship between multiple immunological parameters and host resistance: probing the limits of reductionism

Although reductionist experimental designs are excellent for identifying cells, molecules, or functions involved in resistance to particular microbes or cancer cells, they do not provide an integrated, quantitative view of immune function. In the present study, mice were treated with either dexamethasone (DEX) or cyclosporin A (CyA), and immune function and host resistance were evaluated. Multivariate statistical methods were used to describe the relative importance of a broad range of immunological parameters for host resistance in mice treated with various dosages of DEX. Multiple regression and logistic regression analysis indicated that changes in 24 immunological parameters explained a substantial portion of the changes in resistance to B16F10 tumor cells or streptococcus group B. However, at least 40% of the change in host resistance remained unexplained. DEX at all dosages substantially suppressed numerous relevant immunological parameters, but significantly decreased resistance to Listeria monocytogenes only at the highest dosage. In contrast, CyA substantially decreased resistance to L. monocytogenes at dosages that caused relatively minor suppression of just a few immunological parameters (unfortunately, CyA data and host resistance data for L. monocytogenes were not suitable for multivariate analysis). These results illustrate that mathematical models can be used to explain changes in host resistance on the basis of changes in immune parameters, and that moderate changes in relevant immunological parameters may not produce the types of changes in host resistance expected on the basis of results from reductionist experimental designs.     

The limits of reductionism in the life sciences

In the contemporary life sciences more and more researchers emphasize the "limits of reductionism" (e.g. Ahn et al. 2006a, 709; Mazzocchi 2008, 10) or they call for a move "beyond reductionism" (Gallagher/Appenzeller 1999, 79). However, it is far from clear what exactly they argue for and what the envisioned limits of reductionism are. In this paper I claim that the current discussions about reductionism in the life sciences, which focus on methodological and explanatory issues, leave the concepts of a reductive method and a reductive explanation too unspecified. In order to fill this gap and to clarify what the limits of reductionism are I identify three reductive methods that are crucial in the current practice of the life sciences: decomposition, focusing on internal factors, and studying parts in isolation. Furthermore, I argue that reductive explanations in the life sciences exhibit three characteristics: first, they refer only to factors at a lower level than the phenomenon at issue, second, they focus on internal factors and thus ignore or simplify the environment of a system, and, third, they cite only the parts of a system in isolation.     

The conceptualisation of health and disease in veterinary medicine

Background  

The concept of health, as well as the concept of disease, is central in veterinary medicine. However, the definitions "health" and "disease" are not generally acknowledged by veterinarians. The aim of this study was to examine how the concepts "health" and "disease" are defined in veterinary textbooks.     

Landscapes of Devils: Tensions of Place and Memory in the Argentinean Chaco

Landscapes of Devils: Tensions of Place and Memory in the Argentinean Chaco . Gastón R. Gordillo. Durham, NC: Duke University Press, 2005. 304 pp.     

The peripherality of reductionism in the development of molecular biology

Journal of the History of Biology - I have not attempted to provide here an analysis of the methodology of molecular biology or molecular genetics which would demonstrate at what specific points a...     

Chance and the origin of life

Random chemical reactions in the Earth's primitive hydrosphere could have generated no more than 200 bits of information, whereas the first Darwinian organism must have encoded about a million bits, and therefore could not have arisen by chance. This information gap is bridged by separating reproduction from organism, and postulating a reproductive chemical community that would generate information by proto-Darwinian evolution. The information content of the initial community could have been as low as 160 bits, and its evolution might have led to the first Darwinian cell.     

Chance and the origin of life

Random chemical reactions in the Earth's primitive hydrosphere could have generated no more than 200 bits of information, whereas the first Darwinian organism must have encoded about a million bits, and therefore could not have arisen by chance. This information gap is bridged by separating reproduction from organism, and postulating a reproductive chemical community that would generate information by proto-Darwinian evolution. The information content of the initial comunity could have been as low as 160 bits, and its evolution might have led to the first Darwinian cell.     

Representing Culture in Malaysian Cultural Theme Parks: Tensions and Contradictions

Cultural representation is nowhere more significant than in multi-cultural countries, where the mode of representation is instrumental in determining the progress of integration. Ultimately, in the Malaysian context this reflects on the success of, and is intrinsically linked to, the affirmative action policies that benefit the majority Malays. This paper highlights the representation of culture through the medium of three cultural theme parks in Peninsular Malaysia, built to promote ‘unity through diversity’ and a re-imaging of the past traditions and mythical landscape of this Southeast Asian economic powerhouse. A central aim is to bring together and make sense of how the notions of nostalgia, nationalism and economic success in cultural tourism all come to bear on representations in cultural theme parks.