Introductions do not compensate for functional and phylogenetic losses following extinctions in insular bird assemblages

The ratio of species extinctions to introductions has been comparable for many insular assemblages, suggesting that introductions could have ‘compensated’ for extinctions. However, the capacity for introduced species to replace ecological roles and evolutionary history lost following extinction is unclear. We investigated changes in bird functional and phylogenetic diversity in the wake of extinctions and introductions across a sample of 32 islands worldwide. We found that extinct and introduced species have comparable functional and phylogenetic alpha diversity. However, this was distributed at different positions in functional space and in the phylogeny, indicating a ‘false compensation’. Introduced and extinct species did not have equivalent functional roles nor belong to similar lineages. This makes it unlikely that novel island biotas composed of introduced taxa will be able to maintain ecological roles and represent the evolutionary histories of pre‐disturbance assemblages and highlights the importance of evaluating changes in alpha and beta diversity concurrently.     

Harmonising measurements of 8-oxo-7,8-dihydro-2'-deoxyguanosine in cellular DNA and urine

Levels of oxidatively damaged cellular DNA and urinary excretion of damaged 2'-deoxyribonuclosides are widely measured in biomonitoring studies examining the role of oxidative stress induced by environmental exposures, lifestyle factors and development of disease. This has promoted efforts to harmonise measurements of oxidised guanine nucleobases by the variety of analytical approaches for DNA and urinary levels of damage, in multi-laboratory trials that are centred in Europe. The large inter-laboratory variation reported of values of oxidatively damaged DNA is reduced by harmonising assay protocols. Recent attention on optimal conditions for the comet assay may lead to better understanding of the most critical steps in procedure, which generate variation in DNA damage levels between laboratories. Measurements of urinary excretion of oxidatively generated 8-oxo-7,8-dihydro-2'-deoxyguanosine also show large differences between different methods, where chromatographic techniques generally show more reliable results than antibody-based methods. In this case, standardising calibrants is aimed at improving within technique agreement.     

Multimodal Magnetic Resonance Imaging Study of Treatment-Na?ve Adults with Attention-Deficit/Hyperactivity Disorder

Background

Attention-Deficit/Hiperactivity Disorder (ADHD) is a prevalent disorder, but its neuroanatomical circuitry is still relatively understudied, especially in the adult population. The few morphometric magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) studies available to date have found heterogeneous results. This may be at least partly attributable to some well-known technical limitations of the conventional voxel-based methods usually employed to analyze such neuroimaging data. Moreover, there is a great paucity of imaging studies of adult ADHD to date that have excluded patients with history of use of stimulant medication.

Methods

A newly validated method named optimally-discriminative voxel-based analysis (ODVBA) was applied to multimodal (structural and DTI) MRI data acquired from 22 treatment-naïve ADHD adults and 19 age- and gender-matched healthy controls (HC).

Results

Regarding DTI data, we found higher fractional anisotropy in ADHD relative to HC encompassing the white matter (WM) of the bilateral superior frontal gyrus, right middle frontal left gyrus, left postcentral gyrus, bilateral cingulate gyrus, bilateral middle temporal gyrus and right superior temporal gyrus; reductions in trace (a measure of diffusivity) in ADHD relative to HC were also found in fronto-striatal-parieto-occipital circuits, including the right superior frontal gyrus and bilateral middle frontal gyrus, right precentral gyrus, left middle occipital gyrus and bilateral cingulate gyrus, as well as the left body and right splenium of the corpus callosum, right superior corona radiata, and right superior longitudinal and fronto-occipital fasciculi. Volumetric abnormalities in ADHD subjects were found only at a trend level of significance, including reduced gray matter (GM) in the right angular gyrus, and increased GM in the right supplementary motor area and superior frontal gyrus.

Conclusions

Our results suggest that adult ADHD is associated with neuroanatomical abnormalities mainly affecting the WM microstructure in fronto-parieto-temporal circuits that have been implicated in cognitive, emotional and visuomotor processes.     

Tenascin-C and carcinoma cell invasion in oral and urinary bladder cancer

Carcinoma invasion is a complex process regulated by genetic and epigenetic factors as well. A relevant supportive condition for cancer cell migration is the reorganization of the extracellular matrix (ECM), which is realized in an orchestrated multicellular manner including carcinoma cells and stromal fibroblasts. An important key player in the process of ECM reorganization is Tenascin-C (Tn-C). The molecule occurs as different isoforms generated by alternative splicing and de novo glycosylation. Large variants of Tn-C are abundantly re-expressed in the invasive front of many carcinoma types. A special role for initiating migration and accompanied epithelial to mesenchymal transition has been suggested. Here, we review the current knowledge concerning the tumor biological importance of Tn-C, the synthesis and alternative splicing during the invasive process in general, and give an overview on the impact of Tn-C in urothelial carcinoma of the urinary bladder (UBC) and oral squamous cell carcinoma (OSCC).     

Relationships between habitat structure and fish communities on coral

The influence of habitat structure on reef-fish communities at Bar Reef Marine Sanctuary, Sri Lanka, was investigated. The relationship between habitat characteristics and the distribution and abundance of 135 species of fishes was examined on two reef types: coral and sandstone reefs. Results suggested that the reef-fish communities were strongly influenced by various aspects of reef structure. However, relationships between habitat variables and fish communities structure, varied between the two reef types. Fish species diversity was correlated with a number of habitat variables on the sandstone reefs, although structural complexity seemed to play the dominant role. There were no correlations between habitat structure and fish diversity on the coral reefs. Total abundance was not related to any one habitat parameter on either reef type. However, abundances of some species, families and trophic groups were correlated with habitat features. These specific correlations were commonly related to food or shelter availability. For example, coral feeders were correlated with live coral cover, and pomacentrid species, which used branching corals for protection, showed a significant relationship with the density of Acropora colonies. This shows that a summary statistic such as total abundance may hide important information. Effects of habitat structure on the distribution patterns of the fish communities was further investigated using multi-dimensional scaling ordination (MDS) and the RELATE-procedure. With the MDS ordinations for both habitat and fish-community composition it was possible to show that the multivariate pattern between the two ecological components was clearly correlated.     

Intra-articular hyaluronic acid for the treatment of osteoarthritis of the knee: systematic review and meta-analysis

Background

Osteoarthritis of the knee affects up to 10% of the elderly population. The condition is frequently treated by intra-articular injection of hyaluronic acid. We performed a systematic review and meta-analysis of randomized controlled trials to assess the effectiveness of this treatment.

Methods

We searched MEDLINE, EMBASE, CINAHL, BIOSIS and the Cochrane Controlled Trial Register from inception until April 2004 using a combination of search terms for knee osteoarthritis and hyaluronic acid and a filter for randomized controlled trials. We extracted data on pain at rest, pain during or immediately after movement, joint function and adverse events.

Results

Twenty-two trials that reported usable quantitative information on any of the predefined end points were identified and included in the systematic review. Even though pain at rest may be improved by hyaluronic acid, the data available from these studies did not allow an appropriate assessment of this end point. Patients who received the intervention experienced a reduction in pain during movement: the mean difference on a 100-mm visual analogue scale was –3.8 mm (95% confidence interval [CI] –9.1 to 1.4 mm) after 2–6 weeks, –4.3 mm (95% CI –7.6 to –0.9 mm) after 10–14 weeks and –7.1 mm (95% CI –11.8 to –2.4 mm) after 22–30 weeks. However, this effect was not compatible with a clinically meaningful difference (expected to be about 15 mm on the visual analogue scale). Furthermore, the effect was exaggerated by trials not reporting an intention-to-treat analysis. No improvement in knee function was observed at any time point. Even so, the effect of hyaluronic acid on knee function was more favourable when allocation was not concealed. Adverse events occurred slightly more often among patients who received the intervention (relative risk 1.08, 95% CI 1.01 to 1.15). Only 4 trials explicitly reported allocation concealment, had blinded outcome assessment and presented intention-to-treat data.

Interpretation

According to the currently available evidence, intra-articular hyaluronic acid has not been proven clinically effective and may be associated with a greater risk of adverse events. Large trials with clinically relevant and uniform end points are necessary to clarify the benefit–risk ratio.Osteoarthritis affects about 10% of the population over 55 years of age. Of those, one-quarter are severely disabled.¹ The condition is characterized by degeneration of the articular cartilage and subsequent subchondral bone changes. The underlying mechanisms remain unknown, but the glycosaminoglycan–proteoglycan matrix may play a major role.²Hyaluronic acid, a glycosaminoglycan, is widely used for the treatment of osteoarthritis of the knee. A survey of 2 general practices in the United Kingdom showed that about 15% of patients with osteoarthritis received intra-articular treatment with glucosamine sulfates.³ The costs of such treatment are significant. At present, 1 syringe of hyaluronic acid costs at least Can$130 (US$110). The treatment of knee osteoarthritis is covered by the US Medicare program but not by provincial formularies in Canada. In Austria (which has 8 million inhabitants) more than 10 million euros (approximately US$12 million or Can$15 million) is spent by social insurance programs annually for hyaluronic acid preparations (excluding the cost of application).Hyaluronic acid has beneficial effects in vitro.⁴ Because of its viscoelastic quality, it may replace synovial fluid. Furthermore, it may reduce the perception of pain. Beneficial molecular and cellular effects have also been reported.^2,4 Hyaluronic acid is frequently applied by intra-articular injection, but the evidence concerning its clinical relevance is conflicting. The European League against Rheumatism (EULAR) recommends the intra-articular application of hyaluronic acid as “category 2” evidence (at least 1 controlled study without randomization).⁵ The American College of Rheumatology recommends intra-articular hyaluron therapy for patients with no response to nonpharmacologic therapy and simple analgesics.⁶ In contrast, other specialists have concluded that “hyaluronate sodium is not efficacious” in the treatment of osteoarthritis.⁷ The first state-of-the-art systematic review and meta-analysis was published recently,⁸ and its authors concluded “that intra-articular hyaluronic acid, at best, has a small effect.” We performed a systematic review and meta-analysis of the effect of intra-articular hyaluronic acid for the treatment of osteoarthritis of the knee. In contrast to 2 previous meta-analyses on this subject,^8,9 we used a different approach to data synthesis and interpretation: instead of analyzing a composite effect size over time, we allocated trial data, when possible, to 3 outcome groups that we assumed would be relevant for patients with osteoarthritis. We specifically looked at pain at rest, pain during exercise and joint function as distinct outcomes, measured repeatedly over time. In addition, we assessed adverse events and the impact of both trial quality and molecular mass of the product. This analysis allows us to provide important additional insight into the effects of intra-articular administration of hyaluronic acid for the treatment of osteoarthritis of the knee.     

Involvement of the Shewanella oneidensis decaheme cytochrome MtrA in the periplasmic stability of the beta-barrel protein MtrB

The Shewanella oneidensis outer membrane β-barrel protein MtrB is part of a membrane-spanning protein complex (MtrABC) which is necessary for dissimilatory iron reduction. Quantitative PCR, heterologous gene expression, and mutant studies indicated that MtrA is required for periplasmic stability of MtrB. DegP depletion compensated for this MtrA dependence.     

Do bushmeat consumers have other fish to fry?

The overexploitation of tropical forests for bushmeat and of the oceans for fish are two of the most important threats to global biodiversity. Both phenomena also have manifold implications for human livelihoods and food security. A recent article by Brashares et al. indicates that these two resources are linked: when regional fish supplies are low, local bushmeat hunting intensifies. Although coordinated management of bushmeat and fisheries is thus needed, gaps in our knowledge of these systems must first be filled.