A new flow chamber for the study of shear stress and transmural pressure upon cells adhering to a porous biomaterial

Biomaterials used in some biomedical devices are porous and exposed to normal and tangential flow of biofluids. To examine the influence of flow induced forces on the morphology and the biochemical responses of cells adhering to such biomaterials, a Hele-Shaw cell with a porous bottom wall was designed and characterized experimentally. Theoretical predictions for the flow in the chamber are provided and allow to quantify the shear stress and/or transmural pressure exerted on cells. It is thus possible to follow up continuously the shape changes of cells that are adherent on a permeable membrane used in bioreactors.     

Dynamics of Salmonella enterica and antimicrobial resistance in the Brazilian poultry industry and global impacts on public health

Non-typhoidal Salmonella enterica is a common cause of diarrhoeal disease; in humans, consumption of contaminated poultry meat is believed to be a major source. Brazil is the world’s largest exporter of chicken meat globally, and previous studies have indicated the introduction of Salmonella serovars through imported food products from Brazil. Here we provide an in-depth genomic characterisation and evolutionary analysis to investigate the most prevalent serovars and antimicrobial resistance (AMR) in Brazilian chickens and assess the impact to public health of products contaminated with S. enterica imported into the United Kingdom from Brazil. To do so, we examine 183 Salmonella genomes from chickens in Brazil and 357 genomes from humans, domestic poultry and imported Brazilian poultry products isolated in the United Kingdom. S. enterica serovars Heidelberg and Minnesota were the most prevalent serovars in Brazil and in meat products imported from Brazil into the UK. We extended our analysis to include 1,259 publicly available Salmonella Heidelberg and Salmonella Minnesota genomes for context. The Brazil genomes form clades distinct from global isolates, with temporal analysis suggesting emergence of these Salmonella Heidelberg and Salmonella Minnesota clades in the early 2000s, around the time of the 2003 introduction of the Enteritidis vaccine in Brazilian poultry. Analysis showed genomes within the Salmonella Heidelberg and Salmonella Minnesota clades shared resistance to sulphonamides, tetracyclines and beta-lactams conferred by sul2, tetA and bla_CMY-2 genes, not widely observed in other co-circulating serovars despite similar selection pressures. The sul2 and tetA genes were concomitantly carried on IncC plasmids, whereas bla_CMY-2 was either co-located with the sul2 and tetA genes on IncC plasmids or independently on IncI1 plasmids. Long-term surveillance data collected in the UK showed no increase in the incidence of Salmonella Heidelberg or Salmonella Minnesota in human cases of clinical disease in the UK following the increase of these two serovars in Brazilian poultry. In addition, almost all of the small number of UK-derived genomes which cluster with the Brazilian poultry-derived sequences could either be attributed to human cases with a recent history of foreign travel or were from imported Brazilian food products. These findings indicate that even should Salmonella from imported Brazilian poultry products reach UK consumers, they are very unlikely to be causing disease. No evidence of the Brazilian strains of Salmonella Heidelberg or Salmonella Minnesota were observed in UK domestic chickens. These findings suggest that introduction of the Salmonella Enteritidis vaccine, in addition to increasing antimicrobial use, could have resulted in replacement of salmonellae in Brazilian poultry flocks with serovars that are more drug resistant, but less associated with disease in humans in the UK. The plasmids conferring resistance to beta-lactams, sulphonamides and tetracyclines likely conferred a competitive advantage to the Salmonella Minnesota and Salmonella Heidelberg serovars in this setting of high antimicrobial use, but the apparent lack of transfer to other serovars present in the same setting suggests barriers to horizontal gene transfer that could be exploited in intervention strategies to reduce AMR. The insights obtained reinforce the importance of One Health genomic surveillance.     

Hsp40 Chaperones Promote Degradation of the hERG Potassium Channel

Loss of function mutations in the hERG (human ether-a-go-go related gene or KCNH2) potassium channel underlie the proarrhythmic cardiac long QT syndrome type 2. Most often this is a consequence of defective trafficking of hERG mutants to the cell surface, with channel retention and degradation at the endoplasmic reticulum. Here, we identify the Hsp40 type 1 chaperones DJA1 (DNAJA1/Hdj2) and DJA2 (DNAJA2) as key modulators of hERG degradation. Overexpression of the DJAs reduces hERG trafficking efficiency, an effect eliminated by the proteasomal inhibitor lactacystin or with DJA mutants lacking their J domains essential for Hsc70/Hsp70 activation. Both DJA1 and DJA2 cause a decrease in the amount of hERG complexed with Hsc70, indicating a preferential degradation of the complex. Similar effects were observed with the E3 ubiquitin ligase CHIP. Both the DJAs and CHIP reduce hERG stability and act differentially on folding intermediates of hERG and the disease-related trafficking mutant G601S. We propose a novel role for the DJA proteins in regulating degradation and suggest that they act at a critical point in secretory pathway quality control.     

Selective choice of sucrose solution concentration by the hovering hawk mothMacroglossum stellatarum

To determine the preference of the hovering hawk mothMacroglossum stellatarum for different sugar concentrations, the foraging behavior of adults were analyzed under laboratory conditions. Six sucrose concentrations (range, 10–60%, w/w) were simultaneously offered in six artificial ab libitum feeders. The number of feeding bouts and the duration of each visit were automatically recorded and stored in a computer. Results showed that the frequency of visits to the feeders did not vary among the different solutions offered, but the gathered volume by the group attained a maximum at between 20 and 50% (w/w). Moths invested more time in front of the feeder with the more concentrated sugar solutions. It was assumed that factors different from maximizing energy intake, such as water balance and viscosity of concentrated nectars, have to be considered in order to understand the observed patterns of nectar choice.     

A colorimetric method to quantify endo-polygalacturonase activity

We report a new colorimetric assay to quantify endo-polygalacturonase activity, which hydrolyzes polygalacturonic acid to produce smaller chains of galacturonate. Some of the reported polygalacturonase assays measure the activity by detecting the appearance of reducing ends such as the Somogyi-Nelson method. As a result of being general towards reducing groups, the Somogyi-Nelson method is not appropriate when studying polygalacturonase and polygalacturonase inhibitors in plant crude extracts, which often have a strong reducing power. Ruthenium Red is an inorganic dye that binds polygalacturonic acid and causes its precipitation. In the presence of polygalacturonase, polygalacturonic acid is hydrolyzed bringing about a corresponding gain in soluble Ruthenium Red. The described assay utilizes Ruthenium Red as the detection reagent which has been used previously in plate-based assays but not in liquid medium reactions. The new method measures the disappearance of the substrate polygalacturonic acid and is compared to the Somogyi-Nelson assay. The experimental results using lemon peel, a fern fronds and castor leaf crude extracts demonstrate that the new method provides a way to the quickly screening of polygalacturonase activity and polygalacturonase inhibitors in plant crude extracts containing high amounts of reducing power. On the other hand, the Ruthenium Red assay is not able to determine the activity of an exo-polygalacturonase as initial velocity and thus would allow the differentiation between endo- and exo-polygalacturonase activities.     

Isomerization and oxidation of vitamin a in cone-dominant retinas: a novel pathway for visual-pigment regeneration in daylight

The first step toward light perception is 11-cis to all-trans photoisomerization of the retinaldehyde chromophore in a rod or cone opsin-pigment molecule. Light sensitivity of the opsin pigment is restored through a multistep pathway called the visual cycle, which effects all-trans to 11-cis re-isomerization of the retinoid chromophore. The maximum throughput of the known visual cycle, however, is too slow to explain sustained photosensitivity in bright light. Here, we demonstrate three novel enzymatic activities in cone-dominant ground-squirrel and chicken retinas: an all-trans-retinol isomerase, an 11-cis-retinyl-ester synthase, and an 11-cis-retinol dehydrogenase. Together these activities comprise a novel pathway that regenerates opsin photopigments at a rate 20-fold faster than the known visual cycle. We suggest that this pathway is responsible for sustained daylight vision in vertebrates.     

Functional Outcomes and Efficiency of Rehabilitation in a National Cohort of Patients with Guillain - Barré Syndrome and Other Inflammatory Polyneuropathies

Objectives

To describe functional outcomes, care needs and cost-efficiency of hospital rehabilitation for a UK cohort of inpatients with complex rehabilitation needs arising from inflammatory polyneuropathies.

Subjects and Setting

186 patients consecutively admitted to specialist neurorehabilitation centres in England with Guillain-Barré Syndrome (n = 118 (63.4%)) or other inflammatory polyneuropathies, including chronic inflammatory demyelinating polyneuropathy (n = 15 (8.1%) or critical illness neuropathy (n = 32 (17.2%)).

Methods

Cohort analysis of data from the UK Rehabilitation Outcomes Collaborative national clinical dataset. Outcome measures include the UK Functional Assessment Measure, Northwick Park Dependency Score (NPDS) and Care Needs Assessment (NPCNA). Patients were analysed in three groups of dependency based on their admission NPDS score: ‘low’ (NPDS<10), ‘medium’ (NPDS 10–24) and ‘high’ (NPDS ≥25). Cost-efficiency was measured as the time taken to offset the cost of rehabilitation by savings in NPCNA-estimated costs of on-going care in the community.

Results

The mean rehabilitation length of stay was 72.2 (sd = 66.6) days. Significant differences were seen between the diagnostic groups on admission, but all showed significant improvements between admission and discharge, in both motor and cognitive function (p<0.0001). Patients who were highly dependent on admission had the longest lengths of stay (mean 97.0 (SD 79.0) days), but also showed the greatest reduction in on-going care costs (£1049 per week (SD £994)), so that overall they were the most cost-efficient to treat.

Conclusions

Patients with polyneuropathies have both physical and cognitive disabilities that are amenable to change with rehabilitation, resulting in significant reduction in on-going care-costs, especially for highly dependent patients.     

Non-coding RNAs as theranostics in human cancers

Theranostics was coined originally as a term used to describe a system that combines diagnosis and therapy, aiming to provide the tools for personalized medicine. This review reasserts the grounds for regarding non-coding RNAs (ncRNA) as theranostics in human cancers. The microRNAs (miRNAs) are the most well studied ncRNAs in recent years; their pivotal role in orchestrating tumor initiation and progression has been confirmed in all types of cancers. Hence, these small ncRNAs have emerged as attractive therapeutic targets and diagnostic tool. Various approaches to use their therapeutic potential have been taken, here we summarize the most important ones. In the near future, the focus of theranostics will be shifted towards longer and mechanistically more versatile ncRNAs, and we included some recent advances supporting this view.