Unraveling the nanostructure of supramolecular assemblies of hydrogen-bonded rosettes on graphite: an atomic force microscopy study

The self-organization of multicomponent tetrarosette assemblies into ordered nanostructures on graphite surfaces has been studied by atomic force microscopy (AFM). Real-space information on the level of individual molecules allowed us to analyze the underlying structure in unprecedented detail. In highly ordered nanorod domains, tetrarosettes 1(3) x (DEB)(12) arrange in the form of parallel rows with a spacing of 4.6 +/- 0.1 nm. High resolution AFM revealed the internal packing of the tetrarosette assemblies in these rows, which can be described by an oblique lattice with a = 2.5 +/- 0.3 nm, b = 5.0 +/- 0.1 nm, and gamma = 122 +/- 3 degrees. The results, together with recent improvements in synthetic approaches, contribute to the development of a general strategy to develop H-bonding-based nanostructures with molecular precision.     

The effects of platelet apheresis in total hip replacement surgery on platelet activation

BACKGROUND: Autologous platelet rich plasma (PRP) harvest with autotransfusion devices has been used for 10 years in cardiac surgery and recently in orthopedics as a blood saving method. The quality of the harvested platelets has not been adequately examined, in part because of methodological difficulties in studying platelet function during surgery. METHODS: Twenty patients undergoing primary total hip replacement (THR) were studied. Ten patients underwent an immediate preoperative platelet apheresis to obtain concentrated platelet rich plasma (c-PRP). The other 10 patients not undergoing apheresis were allocated to a control group. Platelet activation was evaluated as the population expressing P-selectin on the surface of platelets in the c-PRP and in blood samples collected pre-, per- and postoperatively. The method used was flow cytometry. RESULTS AND CONCLUSIONS: A minor population of activated platelets was found to be circulating in the patients' blood, with a highly significant difference between patients (P = 0.005), and with a range of 1-23% in peroperative activation. PRP harvest did not significantly alter platelet activity. The platelet apheresis procedure did not inhibit platelet function in the c-PRP, as judged by a high proportion of platelets that could be activated in ADP stimulation experiments (mean value +/- SD 86% +/- 7.5%).     

Prothrombin activity and concentration in healthy subjects with and without the prothrombin G20210A mutation

A synthetic pentasaccharide, containing an intact antithrombin III (ATIII) binding site that is in clinical studies a specific antifactor Xa agent, serves as a substrate for a heparin lyase (heparinase I, EC 4.2.2.7) from Flavobacterium heparinum. Heparinase I, currently being assessed as a heparin reversal agent, also reverses the antifactor Xa activity of this synthetic pentasaccharide by breaking it down to inactive disaccharide and trisaccharide products.     

Quantitative assessment of nicotinic acetylcholine receptor proteins in the cerebral cortex of Alzheimer patients

Cholinergic transmission has for long been known to be one of the most severely affected systems in Alzheimer's disease (AD), resulting clinically in massive cognitive deficits. The molecular basis of this dysfunction--on both the pre- and the postsynaptic sites--is still a matter of ongoing investigations. Here, we report on the quantitative assessment of nicotinic acetylcholine receptor isoform expression in AD vs. control cortices. For both subunit proteins assessed, the alpha4 and the alpha7 isoform, highly significant decreases in diseased vs. normal cortices were observed. Both alpha4 and alpha7 subunits are known to be important constituents in hetero- (alpha4beta2) and homooligomeric (alpha7) receptor subtypes. Their decreased expression may contribute to the decreased nicotinic binding known to be accompanied by AD and severe cognitive deficits. The quantitative assessment of nicotinic acetylcholine receptor expression will help to determine those subunits suited as targets for pharmacological stimulation.     

Improving the use of research evidence in guideline development: 6. Determining which outcomes are important

Background  

The World Health Organization (WHO), like many other organisations around the world, has recognised the need to use more rigorous processes to ensure that health care recommendations are informed by the best available research evidence. This is the sixth of a series of 16 reviews that have been prepared as background for advice from the WHO Advisory Committee on Health Research to WHO on how to achieve this.