Animal models experimental data

Before discussing the animal data it is important to note that caffeine is metabolized differently in experimental animals than it is in humans. This is particularly so in the rat, which is the most common experimental model used. Therefore results in animals, either positive or negative, cannot be directly applied to humans. However, since caffeine itself and some of its metabolites are present in both the animal experiments and during human exposure, an adverse effect of caffeine in an animal model should be verified or excluded in the human. 

Recent experimental data, coming particularly from animal models of IBD, are consistent with the hypothesis that gut flora and bacterial products are implicated in the initiation and/or perpetuation of chronic intestinal inflammation. Purified bacterial products can initiate and perpetuate experimental colitis [1,2]. 

Immunotoxicology data most often available for use in risk assessment is derived from experimental animal studies. Although animal models provide an opportunity to establish more reliable exposure estimates and conduct more informative tests than human studies, the level of accuracy that can be achieved using such data in extrapolating to humans is often a matter of debate. In immunotoxicology testing, a set of tests usually referred to... 

A concerted effort is needed to increase our understanding of the transfer and uptake of reactive gases in the lung. A program in this field should involve in vitro model studies, animal experiments, and clinical studies. More information is required on the chemical, physical, and morphologic properties of the mucous layer and the kinetics of the reactions of ozone in the mucous and tissue layers. Experimental data on uptake and dosage for ozone and other oxidants are difficult to obtain for the tracheobronchial and pulmonary regions. Such data for animals and humans will be needed to test the present simple transport models, before further refinements are made. 

This model appears inadequate, for a number of reasons. Although experimental data show that less sulfur dioxide than ozone penetrates the. nasal passages in animals, as predicted by the model, much more ozone is predicted to penetrate than was demonstrated by Yokoyama and... 

An improved gas-uptake model should incorporate the features of the DuBois and Rogers model and the McJilton et al. model. As shown in Figure 7-2 the model for gas uptake in the airways should include separate layers for mucous-serous fluid epithelial tissue and blood. Development of such a model awaits reliable data and methods for predicting the coefficient of diffusion of pollutant gases in tissue and information on the rates of local perfusion of blood and lymph in the bronchial epithelium. Experimental data from humans and animals on the rate of sulfur dioxide absorption in blood could be used to make improved estimates of the tissue-diffusion coefficients in vivo. 

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