Fluorophore-tagged GPCR ligands

Fluorescently tagged drug molecules can be successfully employed to visualize the location of their receptor target at the single-cell level. Furthermore, if their binding to the receptor is reversible, one can now obtain detailed pharmacological information such as affinity using single-molecule detection techniques. When coupled to the growing exploitation of fluorescence-based read-outs in high throughput and high content screening, it is clear that fluorescent molecules offer a safer, more powerful and more versatile alternative to radioligands in molecular pharmacology and drug discovery. GPCR pharmacology has benefited enormously from the application of fluorescence-based technologies and we now possess a much greater understanding of this receptor family's basic molecular mechanisms of action through the careful design and judicious use of fluorescent peptide and small-molecule-based ligands.     

Structure-activity relationships of 1-alkyl-5-(3,4-dichlorophenyl)-5-{2-[3-(substituted)-1-azetidinyl]-ethyl}-2-piperidones. Part 2: Improving oral absorption

A series of piperidone analogues of 1b-q, seeking replacements for the polar sulfamide moiety in clinical candidate UK-224,671 1a, possessing reduced H-bonding potential as a strategy to improve oral absorption, were prepared. These studies led to the successful identification of 1n, which demonstrated equivalent pharmacology and metabolic stability to 1a, and greatly improved oral absorption as assessed in rat PK studies.     

Pharmacogenetics in drug development

Over the last two decades, identification of polymorphisms that influence human diseases has begun to have an impact on the provision of medical care. The promise of genetics lies in its ability to provide insights into an individual's susceptibility to disease, the likely nature of the disease and the most appropriate therapy. For much of its history, pharmacogenetics (PGx-the use of genetic information to impact drug choice) has been limited to comparatively simple phenotypes such as plasma drug levels. Progress in genetics technologies has broadened the scope of PGx efficacy and safety studies that can be implemented, impacting on a broad spectrum of drug discovery and development activities. Recent PGx data show the ability of this approach to generate information that can be applied to dose selection, efficacy determination and safety issues. This in turn will lead to significant opportunities to affect both the approach to clinical development and the probability of success--the latter being an important aspect for pharmaceutical companies and for the patients who will benefit from these new medicines.     

Performance of orientation sensors for use with a functional electrical stimulation mobility system

The purpose of this study was to verify the performance of recently developed body-worn sensor packs against 3D motion analysis of trunk and lower-limb movements. Five sensor packs, each consisting of rate gyroscope and two 2-D accelerometers controlled by a microprocessor were attached to the trunk, thighs, and shanks of an able bodied subject. A 6-camera motion analysis system (MAS) recorded multiple trials of sit-to-stand movements and normal walking. Time domain signals from each sensor pack were significantly correlated (r = 0.90-0.99;p < 0.05) with a root mean square errors of less than 5 degrees when compared against the same limb angle measurements calculated by the MAS. These data demonstrate that these external sensor packs are accurate devices for measuring trunk and lower-limb sagittal plane orientation in real-time.     

Sleep and circadian phase in a ship's crew

Numerous factors influence the increased health risks of seamen. This study investigated sleep (by actigraphy) and the adaptation of the internal clock in watch-keeping crew compared to day workers, as possible contributory factors. Fourteen watch keepers, 4 h on, 8 h off (0800-1200/2000-2400 h, 1200-1600/2400-0400 h, 1600-2000/0400-0800 h) (fixed schedule, n = 6; rotating by delay weekly, n = 8), and 12 day workers participated during a voyage from the United Kingdom to Antarctica. They kept daily sleep diaries and wore wrist monitors for continuous recording of activity. Sleep parameters were derived from activity using the manufacturer's software and analyzed by repeated-measures ANOVA using SAS 8.2. Sequential urine samples were collected for 48 h weekly for 6-sulphatoxymelatonin measurement as an index of circadian rhythm timing. Individuals working watches of 1200-1600/2400-0400 h and 1600-2000/0400-0800 h had 2 sleeps daily, analyzed separately as main sleep (longest) and 2nd sleep. Main sleep duration was shorter in watch keepers than in day workers (p < 0.0001). Objective sleep quality was significantly compromised in rotaters compared to both day workers and fixed watch keepers, the most striking comparisons being sleep efficiency (percentage desired sleep time spent sleeping) main sleep (p < 0.0001) and sleep fragmentation (an index of restlessness) main sleep (p < 0.0001). The 2nd sleep was substantially less efficient than was the main sleep (p < 0.0001) for all watch keepers. There were few significant differences in sleep between the different watches in rotating watch keepers. Circadian timing remained constant in day workers. Timing of the 6-sulphatoxymelatonin rhythm was later for the watch of 1200-1600/2400-0400 h than for all others (1200-1600/2400-0400 h, 5.90 +/- 0.85 h; 1600-2000/0400-0800 h, 1.5 +/- 0.64 h; 0800-1200/ 2000-2400 h, 2.72 +/- 0.76 h; days, 2.09 +/- 0.68 h [decimal hours, mean +/- SEM]: ANOVA, p < 0.01). This study identifies weekly changes in watch time as a cause of poor sleep in watch keepers. The most likely mechanism is the inability of the internal clock to adapt rapidly to abrupt changes in schedule.     

Biodiversity management of fens and fen meadows by grazing,cutting and burning

Question: Can the biodiversity of fens in Europe and North America be maintained through the use of grazing (especially cattle grazing), fire, and/or cutting? Location: European and North American fens. Methods: This paper is a review of the literature on the effects of grazing, fire and cutting on fens, to explore the relationship between management and biodiversity in fens. Results: A reduction of cattle grazing, mowing and burning in fens has led to a reduction in biodiversity in fens. The vegetation of abandoned fens shifts to trees and shrubs after 10–15 years, which shade the smaller and rarer species of these wetlands. While careful use of fire is used to manage fens in North America, it is not widely used in European fens, perhaps because the peat of drained fens may catch fire. Cattle grazing cannot be considered a natural disturbance in North America, since cattle did not evolve on that continent. In Europe, cattle do not generally graze in unaltered fens, but they do use slightly drained fen meadows. Conclusions: Three approaches have been used to control the dominance of tall woody and herbaceous species in abandoned fens, including the re‐introduction of cattle, mowing, and burning. Overgrazing results in a permanent reduction in biodiversity, therefore cattle re‐introduction must be approached cautiously. In Europe, but not in North America, mowing has been an important management tool, and mowing has been successful in maintaining species richness, particularly in fens that have been mowed annually for centuries. Fire has been the most common and successful management tool in North America although it is not effective in removing shrubs that have become large. Because the problems and solutions are similar, the literature of both European and North American fen management can be analyzed to better assess the management of fens on both continents. Many management questions require further study and these are listed in the paper.     

Detection of nucleotide binding to Na,K-ATPase in an aqueous membrane suspension by 13C cross-polarization magic-angle spinning NMR spectroscopy

Binding of uniformly (13)C labelled ATP to Na,K-ATPase was studied by (13)C cross-polarization magic-angle spinning (CP-MAS) NMR. In the presence of 30 mM Na(+) , and with sample- and time-averaging, NMR spectra obtained at 4 degrees C exhibited several resonances for the bound nucleotide. Chemical shifts suggested that site-specific changes in the micro-environment or conformation of the nucleotide occurred in the high affinity binding site. These experiments permit further studies of nucleotide dynamics, structure and binding under physiologically relevant conditions.