Acro-osteolysis in systemic sclerosis is associated with digital ischaemia and severe calcinosis.

OBJECTIVES: Acro-osteolysis (bony resorption of the terminal digital tufts) is a well-recognized, but under-researched, manifestation of SSc. Our aim was to investigate the hypothesis that acro-osteolysis is associated with (i) the severity of digital ischaemia and (ii) the presence of calcinosis. METHODS: This was a retrospective study of 101 patients with SSc in whom hand radiographs taken between 2001 and May 2008 were available for review. These radiographs were graded for severity of acro-osteolysis on a 0-4-point scale for each finger (0 = normal bone structure, 4 = severe pencilling of the terminal phalanges). From these scores, patients were subdivided into the following two groups: normal/minimal acro-osteolysis and moderate/severe acro-osteolysis. The presence or absence of calcinosis (mild, moderate or severe) was also documented. RESULTS: Of the 101 patients, 68 were grouped as normal/minimal acro-osteolysis and 33 as moderate/severe acro-osteolysis. Forty-five had severe digital ischaemia: 25 (76%) of the patients with moderate/severe acro-osteolysis compared with 20 (29%) of those with normal/minimal acro-osteolysis (multifactorial analysis: P < 0.001). Patients with moderate/severe acro-osteolysis were more likely to have severe calcinosis (33% vs 13%), but this was not statistically significant after adjustment for potential confounders. CONCLUSION: Acro-osteolysis was strongly associated with severe digital ischaemia. The potential association with severe calcinosis merits further study. Prospective studies are required to investigate acro-osteolysis as a marker of digital vascular disease progression and of treatment response.

Feeling the music: The feel and sound of songs attenuate pain.

Background: Extensive research has demonstrated that music and touch can separately attenuate perceived pain intensity. However, little research has investigated how auditory and tactile stimulation can synergistically enhance pain attenuation by music. In the current study, we investigated whether tactile stimulation can enhance music-induced analgesia for noxious force stimulation on the fingertip. Methods: We systematically applied force to 34 listeners' fingertips to induce pain. We then compared the force measurement (in Newton) that gave rise to the same perceived moderate pain intensity when listeners were presented their self-selected liked or disliked song with auditory-only, tactile-only and auditory-tactile stimulation. Higher force indicated less perceived pain. The tactile stimulation were low-frequency modulations extracted from the songs and presented as vibrations on the wrist. Results: The results showed a significant interaction between song preference and stimulation condition. Listeners had higher force measurements at the same moderate pain for their liked compared to disliked song only in the auditory-tactile condition. They also had higher force measurements for their liked song with auditory-tactile stimulation compared to the other remaining conditions except for the liked song with auditory-only stimulation. Conclusions: The addition of tactile stimulation enhanced music-induced analgesia which reduced subjective pain intensity. The findings suggest that combined auditory and tactile stimulation may increase the affective content of self-selected preferred music, which may stimulate affective and motivation mechanisms which inhibit pain transmission.

The interactions and hierarchical effects of long-term agricultural stressors on soil bacterial communities.

Soils are subjected to multiple anthropogenic modifications, but the synergistic impacts of simultaneous environmental stressors on below-ground communities are poorly understood. We used a large-scale (1152 plots), long-term (26 years), multi-factorial grassland experiment to assess the impact of five common agricultural practises (pesticides, herbicide, liming, fertilizers and grazing exclusion) and their interactive effects on the composition and activity of soil microbial communities. We confirmed that pH strongly impacts belowground communities, but further demonstrate that pH strongly mediates the impacts of other management factors. Notably, there was a significant interaction between liming and the effect of pesticide application, with only half of the taxa responding to pesticide being shared in both limed and unlimed treatments. Likewise, nutrient amendments significantly altered bacterial community structure in acidic soils. Not only do these results highlight an hierarchy of effect of commonly used agricultural practices but also the widespread interactions between treatments: many taxa were significantly affected by interactions between treatments, even in the absence of significant main effects. Furthermore, the results demonstrated that chemical amendments may not percolate deeply into physically unperturbed soils with effects concentrated between 0 and 30 cm, despite 20+ years of treatment. The research shows that future changes to agricultural practices will need to consider interactions among multiple factors.

Resource-dependent attenuation of species interactions during bacterial succession.

Bacterial communities are vital for many economically and ecologically important processes. The role of bacterial community composition in determining ecosystem functioning depends critically on interactions among bacterial taxa. Several studies have shown that, despite a predominance of negative interactions in communities, bacteria are able to display positive interactions given the appropriate evolutionary or ecological conditions. We were interested in how interspecific interactions develop over time in a naturalistic setting of low resource supply rates. We assembled aquatic bacterial communities in microcosms and assayed the productivity (respiration and growth) and substrate degradation while tracking community composition. The results demonstrated that while bacterial communities displayed strongly negative interactions during the early phase of colonisation and acclimatisation to novel biotic and abiotic factors, this antagonism declined over time towards a more neutral state. This was associated with a shift from use of labile substrates in early succession to use of recalcitrant substrates later in succession, confirming a crucial role of resource dynamics in linking interspecific interactions with ecosystem functioning.