Mucociliary clearance in COPD can be increased by both a D2/β2 and a standard β2 agonists

SummaryIn addition to breathlessness and cough, excessive mucus production is one of the main symptoms of chronic obstructive pulmonary disease (COPD). Excess mucus coupled with deteriorating mucociliary clearance is associated with a decline in lung function and an increased risk of death from pulmonary infection. The effect of ViozanTM (Sibenadet HCI, AR-C68397AA), a novel dual D2 dopamine receptor, β2-adrenoceptor agonist, on mucociliary clearance was investigated together with that of a β2-adrenoceptor agonist, salbutamol. Using a double blind, parallel group study design, 15 patients with COPD, all habitual smokers, were randomised to receive nebulised sidenadet (3mg tid; n=7) or salbutamol (5mg tid; n=8) for 10 days. Lung mucociliary clearance rates were measured, by a standard radioaerosol technique, before and after the treatment period, as were 24-h sputum volumes. Both sibenadet and salbutamol therapies resulted in significant (P<0.02) enhancement of lung mucociliary clearance. The 24-h sputum volume was significantly reduced following sibenadet therapy (P<0.03) whereas salbutamol therapy had no effect. Our results, in addition to illustrating the effects of a standard β2 agonist on mucociliary clearance, strongly suggest the potential dual benefit of dual-agonist compounds in lessening sputum production whilst simultaneously enhancing mucociliary clearance. For reasons unconnected with the present study, development work on this specific formulation is no longer proceeding

Carbon stable isotopes as a palaeoclimate proxy in vascular plant dominated peatlands

Carbon stable isotope (δ¹³C) records from vascular plant dominated peatlands have been used as a palaeoclimate proxy, but a better empirical understanding of fractionation processes in these ecosystems is required. Here, we test the potential of δ¹³C analysis of ombrotrophic restiad peatlands in New Zealand, dominated by the wire rush (Empodisma spp.), to provide a methodology for developing palaeoclimatic records. We took surface plant samples alongside measurements of water table depth and (micro)climate over spatial (six sites spanning > 10 latitude) and temporal (monthly measurements over 1 year) gradients and analysed the relationships between cellulose δ¹³C values and environmental parameters. We found strong, significant negative correlations between δ¹³C and temperature, photosynthetically active radiation and growing degree days above 0 C. No significant relationships were observed between δ¹³C and precipitation, relative humidity, soil moisture or water table depth, suggesting no growing season water limitation and a decoupling of the expected link between δ¹³C in vascular plants and hydrological variables. δ¹³C of Empodisma spp. roots may therefore provide a valuable temperature proxy in a climatically sensitive region, but further physiological and sub-fossil calibration studies are required to fully understand the observed signal

Measurement of the forward-backward asymmetry in Λ0b and Λ¯0b baryon production in pp¯ collisions at s√=1.96 TeV

We measure the forward-backward asymmetry in the production of Λ0b and Λ¯0b baryons as a function of rapidity in pp¯ collisions at s√=1.96  TeV using 10.4  fb−1 of data collected with the D0 detector at the Fermilab Tevatron collider. The asymmetry is determined by the preference of Λ0b or Λ¯0b particles to be produced in the direction of the beam protons or antiprotons, respectively. The measured asymmetry integrated over rapidity y in the range 0.1<|y|<2.0 is A=0.04±0.07(stat)±0.02(syst)

Experimental evaluation of the effectiveness of weighting regimes in reducing seabird by-catch in the longline toothfish fishery around South Georgia

A series of experiments was carried out in February 1999 at South Georgia (Subarea 48.3) to examine the effects of different weighting regimes on the incidental mortality of birds caught on longlines fishing for toothfish (Dissostichus spp.). Three regimes were examined, with weights of 4.25,8.5 and 12.75 kg attached at 40 m intervals on a Spanishrigged longline. There was a significant reduction in bird mortality when 8.5 kg was used compared to 4.25 kg, but no further significant reduction when 12.75 kg was used. Therefore to minimise seabird by-catch, line-weighting regimes of at least 8.5 kg at 40 m intervals should be used. Results suggested that seabird by-catch on lines using effective weighting regimes may be even further reduced where all lines being set in the vicinity use effective line-weighting regimes. The importance of a good design in experiments of this type is emphasised, because even though conditions may be held as constant as possible within experiments, the ability to separate treatment effects from other sources of variation (e.g. environmental factors) must be preserved

Data from: Decomposing parasite fitness in a two-host, two-parasite system reveals the underpinnings of parasite specialization

The ecological specialization of parasites - whether they can obtain high fitness on very few or very many different host species - is a determining feature of their ecology. In order to properly assess specialization, it is imperative to measure parasite fitness across host species; to understand its origins, fitness must be decomposed into the underlying traits. Despite the omnipresence of parasites with multiple hosts, very few studies assess and decompose their specialization in this way. To bridge this gap, we quantified the infectivity, virulence, and transmission rate of two parasites, the horizontally transmitted microsporidians Anostracospora rigaudi and Enterocytospora artemiae, in their natural hosts, the brine shrimp Artemia parthenogenetica and Artemia franciscana. Our results demonstrate that each parasite performs well on one of the two host species (A. rigaudi on A. parthenogenetica, and E. artemiae on A. franciscana), and poorly on the other. This partial specialization is driven by high infectivity and transmission rates in the preferred host, and is associated with maladaptive virulence and large costs of resistance in the other. Our study represents a rare empirical contribution to the study of parasite evolution in multi-host systems, highlighting the negative effects of under- and over-exploitation when adapting to multiple hosts

experiment 1 - analysis

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experiment 2 - analysis

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experiment 1 - data

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