Objective: European Concerted Action on Sudden Infant Death was set up with the following objectives: 1. To determine the extent to which infants in Europe are put to sleep in prone position and the relative risks associated with doing so. 2. To examine possible risks associated with other current infant care practices. 3. To re-assess risks now associated with other previously known risk factors. DesignČ Case-control data were assembled from 20 centres in Europe over different periods lasting between September 1992 andMarch 1996. Data from on-going surveys in Scandinavia, England, Ireland and Germany were combined with surveys using standard ECAS protocol that were set up in Austria, Belgium, England, France, Holland, Hungary, Italy, Poland, Russia, Spain, Slovenia and the Ukraine. The diagnosis of SIDS was based on autopsy. Between 1 and 4 controls per case, matched for age and date of birth,were randomly selected to represent normal infants. Data on 22 core variables, related to objectives, were available from all surveys. 38 additional variables were abstracted, although they were missing from some protocols. Two composite variables were constructed. SubjectsČ 745 cases of SIDS and 2145 controls from 20 centres in Europe. Method of Analysis: Univariate and multivariate logistic regression. Result of univariate analysis: - OR s for 7 factors were > 10: last found face down: birth weight

In the medical research and in teaching various models are used. They very often use digital (mathematical) modelling (simulation) of various physiological processes. However, mathematical modelling is demanding and therefore not easily accessible. Therefore in this investigation another approach is usedČ analogue simulation. By using the Electronics Workbench software an electronic equivalent circuit is designed, simulating the lung andits ventilation. The circuit is upgraded by including a negative feedback to control alveolar ventilation. Simulations were performed under the conditions in which the negative feedback loop was either open or closed. In the first experimental condition, when negative feedback was not operative, only the immediate consequences of the disturbance could be observed. In the second experimental condition, when negative feedback was operative, complex homeostatic phenomena could be observed. The latter - in principle - minimizesthe consequences of the initial disturbance. Under the conditions in which the negative feedback loop was either open or closed, three different types of disturbance were studiedČ i) increased production of CO2, ii) temporary apnea and iii) increased aiarway resistance (bronchoconstriction). The heterogeneous lung model was used to simulate bronchoconstriction in the entire lung. The heterogeneous lung model was used to simulate bronchoconstriction in only one section, comprising a half of the lung. Increased production of CO2 resulted in an increase of tidal volume and in increased arterial pCO2. The latter was highly dependent on the response of the negative feedback. Temporary apnea resulted in a temporary increase in pCO2. When, in the feedback loop, the delay in signal transfer was relatively large, temporary apnea induced the periodic, i.e. Cheyne-Stokes breathing. Bronchoconstriction which affected the whole lung resulted in a decrease in the tidal volume. (Abstract truncated at 2000 characters).