Prenatal screening to reduce the risks of congenital toxoplasmosis has always been controversial. The debate centres on two questions, first whether prenatal screening can be justified at all and second, if it can, which screening programme is the most effective.

Temperature programmed desorption (TPD) experiments have been performed after dosing an ion-sputtered and annealed polycrystalline Pt surface with CO and H2. The CO-dosing was done both sequentially and simultaneously. With increasing residence time on the surface, the H2-TPD spectra exhibit conversion of the original H2-like features to features similar to the CO-TPD peaks. This provides evidence for the formation of a CO/H surface species through a chemical reaction between adsorbed H and adsorbed CO. The reaction occurs more rapidly when the sample is dosed or held at elevated temperatures, indicating that the reaction is activated.

Tumor necrosis factor-alpha (TNF-alpha) is released from a cell membrane-anchored precursor by proteolytic cleavage. We have shown that broad spectrum synthetic inhibitors of matrix metalloproteinases (MMPs) prevent the processing of the TNF precursor but do not inhibit the release of other cytokines. Purified MMPs, stromelysin, matrilysin, collagenase, and the gelatinases can all cleave a recombinant pro-TNF substrate to yield mature TNF. MMP inhibitors prevent the rise in blood levels of TNF after endotoxin administration in rats and are effective in animal models of inflammatory disease such as adjuvant arthritis. Drugs that inhibit MMP action and TNF release show great promise for the treatment of autoimmune inflammatory diseases.

The chemisorption of CO on a sputtered and annealed polycrystalline Pt surface has been examined using ion scattering spectroscopy (ISS) and temperature programmed desorption (TPD). Data obtained from an isotopic TPD experiment indicate that adsorption is molecular with no detectable CO dissociation. ISS data demonstrate that the CO bonds to the Pt through the C with the O pointing away from the surface and that about 80% of the Pt surface is covered at saturation based on the relative sizes of the ISS Pt peak heights obtained from the clean and CO-saturated surfaces. Coverage versus exposure plots have been determined from both the ISS and TPD data, and the agreement is generally good. The sticking coefficient is close to 1 up to Θ=0.5 and than falls rapidly with increasing exposure to the saturation exposure of 90 L. The Kisliuk adsorption model, which assumes adsorption at a single type of site, is able to provide a good fit of the ISS uptake data but is not as successful in fitting the TPD uptake data.

An investigation into the low temperature (300 to 1000 K) behavior of the hydrogen/polycrystalline zirconium system has revealed an interesting binding state for hydrogen which has a desorption temperature of 500 K. This state involves surface oxygen, believed to be in the form of hydroxyl groups. Furthermore, the surface oxygen appears to attract hydrogen from the metal, suggesting a low energy path for the removal of hydrogen from zirconium.