-The group agreed on sets of uniform sampling criteria, placental gross descriptors, pathologic terminologies, and diagnostic criteria. The terminology and microscopic descriptions for maternal vascular malperfusion, fetal vascular malperfusion, delayed villous maturation, patterns of ascending intrauterine infection, and villitis of unknown etiology were agreed upon. Topics requiring further discussion were highlighted. Ongoing developments in our understanding of the pathology of the placenta, scientific bases of the maternofetoplacental triad, and evolution of the clinical significance of defined lesions may necessitate further refinements of these consensus guidelines. The proposed structure will assist in international comparability of clinicopathologic and scientific studies and assist in refining the significance of lesions associated with adverse pregnancy and later health outcomes.

Word count of main text = 3264 wordsAvon SIDS epidemiology paper 18/11/2008 1 draft Acknowledgement. Funding was provided for these studies by grants from:i

~~ ~ ~Cells of mucoid and non-mucoid Pseudomonas aeruginosa in colonies were at least onethousandfold less sensitive to the antibiotics tobramycin or cefsulodin than were cells of the same bacteria in dispersed suspension. We did not detect any difference between the mucoid form and the non-mucoid form in the antibiotic sensitivity of colonies, from which we infer that the exopolysaccharide of the mucoid form does not contribute to colony-resistance by forming a barrier to antibiotic diffusion. Mathematical models were constructed in order to estimate timecourses of penetration of tobramycin and cefsulodin into biofilms and microcolonies of mucoid and non-mucoid P. aeruginosa. For tobramycin penetration, adsorption of antibiotic to the exopolysaccharide of the glycocalyx and antibiotic uptake by cells were taken into account in the calculations. The longest time-period for the concentration of tobramycin at the base of a biofilm 100 prn deep to rise to 90% of the concentration outside the biofilm was predicted to be 2.4 h. For cefsulodin penetration, irreversible hydrolysis catalysed by p-lactamase was taken into account, using P-lactamase levels taken from the literature. The calculations predicted that the cefsulodin concentration at the base of a biofilm 100pm deep would rise to 90% of the external concentration in 29 s when the /I-lactamase was synthesized at the basal level. For a similar biofilm of bacteria synthesizing enhanced levels of fl-lactamase ('derepressed'), the concentration of cefsulodin at the base was calculated to rise to 41% of the external concentration in about 50s and then remain at that level. This was despite the fact that cefsulodin is a poor substrate for this P-lactamase.

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