2,036 research outputs found
Tegumental proteins of Schistosoma mansoni: complex biomolecules and potent antigens
The passive transfer of monoclonal antibodies, direct vaccination and in vitro assays have all shown that antigens associated with the tegumental membranes of Schistosoma mansoni are capable of mediating protective immune responses against the parasite in animal models. Furthermore, the principal antigens are highly antigenic during natural infection in man and stimulate strong humoral and cellular responses although, at present, their role in mediating protective immune responses in man remains equivocal. This presentation will review the current state of knowledge of the structure and expression of the major antigenic tegumental proteins of the schistosome and will attempt to relate the relevance of their structural features to possible function both in terms of protective immunity and parasite's ability to survive within the definitive host. A focus will be recent advances that have been made in the identification of means of anchoring of the antigenic proteins to the tegumental membrane. In addition, the implications of the structural complexity of the tegumental proteins in terms of their possible utility in vaccination and diagnosis will be considered
Adaptive Avoidance of Reef Noise
Auditory information is widely used throughout the animal kingdom in both terrestrial and aquatic environments. Some marine species are dependent on reefs for adult survival and reproduction, and are known to use reef noise to guide orientation towards suitable habitat. Many others that forage in food-rich inshore waters would, however, benefit from avoiding the high density of predators resident on reefs, but nothing is known about whether acoustic cues are used in this context. By analysing a sample of nearly 700,000 crustaceans, caught during experimental playbacks in light traps in the Great Barrier Reef lagoon, we demonstrate an auditory capability in a broad suite of previously neglected taxa, and provide the first evidence in any marine organisms that reef noise can act as a deterrent. In contrast to the larvae of species that require reef habitat for future success, which showed an attraction to broadcasted reef noise, taxa with a pelagic or nocturnally emergent lifestyle actively avoided it. Our results suggest that a far greater range of invertebrate taxa than previously thought can respond to acoustic cues, emphasising yet further the potential negative impact of globally increasing levels of underwater anthropogenic noise
Binary-state speciation and extinction method is conditionally robust to realistic violations of its assumptions
Phylogenetic comparative methods allow us to test evolutionary hypotheses without the benefit of an extensive fossil record. These methods, however, make simplifying assumptions, among them that clades are always increasing or stable in diversity, an assumption we know to be false. This study simulates hypothetical clades to test whether the Binary State Speciation and Extinction (BiSSE) method can be used to correctly detect relative differences in diversification rate between ancestral and derived character states even as net diversification rates are declining overall. We simulate clades with declining but positive diversification rates, as well those in which speciation rates decline below extinction rates so that they are losing richness for part of their history. We run these analyses both with simulated symmetric and asymmetric speciation rates to test whether BiSSE can be used to detect them correctly. For simulations with a neutral character, the fit for a BiSSE model with a neutral character is better than alternative models so long as net diversification rates remain positive. Once net diversification rates become negative, the BiSSE model with the greatest likelihood often has a non-neutral character, even though there is no such character in the simulation. BiSSE’s usefulness in detecting real asymmetry in speciation rates improves with clade age, even well after net diversification rates have become negative. BiSSE is most useful in analyzing clades of intermediate age, before they have reached peak diversity and gone into decline. After this point, users of BiSSE risk incorrectly inferring differential evolutionary rates when none exist. Fortunately, most studies using BiSSE and similar models focus on rapid, recent diversifications, and are less likely to encounter the biases BiSSE models are subject to for older clades. For extant groups that were once more diverse than now, however, caution should be taken in inferring past diversification patterns without fossil data
Molecular Hydrogen and Paschen-alpha Emission in Cooling Flow Galaxies
We present near-infrared spectra obtained to search for Pa-alpha and
molecular hydrogen lines in edge-darkened (FR I-type) radio galaxies with
bright Halpha emission in the redshift range 0.0535<z<0.15. We find that all
three galaxies in our sample (PKS 0745-191, PKS 1346+26, & PKS2322-12) which
are associated with strong cooling flows also have strong Pa-alpha and H_2
(1-0) S(1) through S(5) emission, while other radio galaxies do not. Together
with earlier observations this confirms claims that cooling flow galaxies are
copious emitters of molecular hydrogen with large H_2 (1-0) S(3)/Pa-alpha
ratios in the range 0.5 to 2. The emission is centrally concentrated within the
inner few kiloparsec and could come from warm (T ~ 1000-1500 K) molecular
material which is being deposited by the cooling flow. We speculate that the
H_2 emission could be related to the interaction between the jets and this
molecular gas.Comment: ApJ Letters, in press, AAS LaTex, preprint also available at
http://www.astro.umd.edu/~hfalcke/publications.html#nirga
Group-based pulmonary telerehabilitation is feasible, safe, beneficial and well-received in patients that have been hospitalised with Covid-19
Introduction Covid-19 has caused worldwide mass hospitalisation. The need for multi-disciplinary post-hospitalisation rehabilitation is becoming increasingly apparent and telerehabilitation has been endorsed. The aim of study was to investigate the feasibility and efficacy of pulmonary telerehabilitation for Covid-19 survivors.Methods A single centre, mixed-methods, fast-track (wait-list), randomised controlled trial of telerehabilitation for patients who have been hospitalised with Covid-19.Participants Forty patients discharged from two University Teaching Hospitals in the North of England. Interventions: Telerehabilitation consisted of twelve exercise classes, six education events and opportunity for peer support. Patients commenced telerehabilitation 14 days after randomisation in the fast-track group and 56 days after randomisation in the wait-list group.Outcome measures and results Descriptive and statistical improvements were noted is several clinical outcome measures. Exercise capacity increased from a median (Q1–Q3) 20 (14–24) sit-to-stand repetitions in one-minute at baseline to 25 (24–30) post-telerehabilitation. Breathlessness rated using the MRC changed from 3.5 (3–4) at baseline to 2 (1.5–3) post-telerehabilitation, with additional favourable outcomes noted in respiratory symptoms measured using numerical rating scales and visual analogue scales (VAS). Quality of life measured using the EQ-VAS improved from 55 (60–70) units at baseline to 70 (55–80) units following telerehabilitation. Improvements in fatigue (FACIT-F) and mood (HADS-D) were also observed. Natural recovery was observed in the wait-list group prior to receiving telerehabilitation, however, improvements were accelerated by early telerehabilitation in the fast-track group.Conclusions We have shown that group-based telerehabilitation is feasible, safe, beneficial and well-received in this population
Septic arthritis in an in vivo murine model induced by Staphylococcus aureus:a comparison between actions of the haemolysin toxin and the effects of the host immune response
AIMS: Staphylococcus aureus is a major cause of septic arthritis, and in vitro studies suggest α haemolysin (Hla) is responsible for chondrocyte death. We used an in vivo murine joint model to compare inoculation with wild type S. aureus 8325-4 with a Hla-deficient strain DU1090 on chondrocyte viability, tissue histology, and joint biomechanics. The aim was to compare the actions of S. aureus Hla alone with those of the animal’s immune response to infection. METHODS: Adult male C57Bl/6 mice (n = 75) were randomized into three groups to receive 1.0 to 1.4 × 10(7) colony-forming units (CFUs)/ml of 8325-4, DU1090, or saline into the right stifle joint. Chondrocyte death was assessed by confocal microscopy. Histological changes to inoculated joints were graded for inflammatory responses along with gait, weight changes, and limb swelling. RESULTS: Chondrocyte death was greater with 8325-4 (96.2% (SD 5.5%); p < 0.001) than DU1090 (28.9% (SD 16.0%); p = 0.009) and both were higher than controls (3.8% (SD 1.2%)). Histology revealed cartilage/bone damage with 8325-4 or DU1090 compared to controls (p = 0.010). Both infected groups lost weight (p = 0.006 for both) and experienced limb swelling (p = 0.043 and p = 0.018, respectively). Joints inoculated with bacteria showed significant alterations in gait cycle with a decreased stance phase, increased swing phase, and a corresponding decrease in swing speed. CONCLUSION: Murine joints inoculated with Hla-producing 8325-4 experienced significantly more chondrocyte death than those with DU1090, which lack the toxin. This was despite similar immune responses, indicating that Hla was the major cause of chondrocyte death. Hla-deficient DU1090 also elevated chondrocyte death compared to controls, suggesting a smaller additional deleterious role of the immune system on cartilage. Cite this article: Bone Joint Res 2022;11(9):669–678
The Phoenix Deep Survey: Extremely Red Galaxies and Cluster Candidates
We present the results of a study of a sample of 375 Extremely Red Galaxies
(ERGs) in the Phoenix Deep Survey, 273 of which constitute a subsample which is
80% complete to K_s = 18.5 over an area of 1160 arcmin^2. The angular
correlation function for ERGs is estimated, and the association of ERGs with
faint radio sources explored. We find tentative evidence that ERGs and faint
radio sources are associated at z > 0.5. A new overdensity-mapping algorithm
has been used to characterize the ERG distribution, and identify a number of
cluster candidates, including a likely cluster containing ERGs at 0.5 < z < 1.
Our algorithm is also used in an attempt to probe the environments in which
faint radio sources and ERGs are associated. We find limited evidence that the
I - K_s > 4 criterion is more efficient than R - K_s > 5 at selecting dusty
star-forming galaxies, rather than passively evolving ERGs.Comment: 14 emulateapj pages, 15 figures, 1 table, accepted for publication in
Astronomical Journal. A version with full resolution figures is available at
http://www.physics.usyd.edu.au/~asmith/research/ERGpaper.pd
Telerehabilitation for patients who have been hospitalised with covid-19: a qualitative study
PurposeThe aim of this qualitative study was to explore the views of participants of a group-based, supervised, telerehabilitation programme, following discharge from hospital with Covid-19. This study was part of a single-centre, fast-track (wait-list), randomised, mixed-methods, feasibility trial of telerehabilitation (Registration: Clinicaltrials.gov reference:285205).MethodsSemi-structured interviews were conducted over a virtual teleconference platform with 10 participants who took part in a telerehabilitation programme following Covid-19 after discharge from an acute hospital. Data were transcribed verbatim and analysed using thematic analysis.ResultsFive themes were important from the participant perspective: telerehabilitation programme as part of the Covid-19 journey; the telerehabilitation programme design and delivery; peer aspects; the role of the instructor; and the role of technology and online delivery.ConclusionsOverall, the telerehabilitation programme was a positive experience for participants. The instructors were central to this positive view as was the group nature of the programme. The group aspect was particularly important in supporting the broader perceived wellbeing gains, such as the sense of enjoyment and reduced social isolation. Several participants would have liked to have continued with the exercises beyond the six-week intervention indicating that the programme could be a way to help people sustain a physically active lifestyle.IMPLICATIONS FOR REHABILITATIONParticipants who were recovering from Covid-19 following hospital admission perceived the telerehabilitation to be a positive experience overall.The group aspect of the telerehabilitation programme was important in supporting the broader perceived wellbeing gains such as the sense of enjoyment and reduced social isolation.Telerehabilitation programmes for Covid-19 may need to include pathways for participants to continue to engage in exercise beyond the time-limited six-week intervention to support ongoing self-management
Sustained adherence to a Mediterranean diet and physical activity on all-cause mortality in the Melbourne Collaborative Cohort Study: application of the g-formula.
BACKGROUND: Adherence to a traditional Mediterranean diet has been associated with lower mortality and cardiovascular disease risk. The relative importance of diet compared to other lifestyle factors and effects of dietary patterns over time remains unknown. METHODS: We used the parametric G-formula to account for time-dependent confounding, in order to assess the relative importance of diet compared to other lifestyle factors and effects of dietary patterns over time. We included healthy Melbourne Collaborative Cohort Study participants attending a visit during 1995-1999. Questionnaires assessed diet and physical activity at each of three study waves. Deaths were identified by linkage to national registries. We estimated mortality risk over approximately 14 years (1995-2011). RESULTS: Of 22,213 participants, 2163 (9.7%) died during 13.6 years median follow-up. Sustained high physical activity and adherence to a Mediterranean-style diet resulted in an estimated reduction in all-cause mortality of 1.82 per 100 people (95% confidence interval (CI): 0.03, 3.6). The population attributable fraction was 13% (95% CI: 4, 23%) for sustained high physical activity, 7% (95% CI: - 3, 17%) for sustained adherence to a Mediterranean-style diet and 18% (95% CI: 0, 36%) for their combination. CONCLUSIONS: A small reduction in mortality may be achieved by sustained elevated physical activity levels in healthy middle-aged adults, but there may be comparatively little gain from increasing adherence to a Mediterranean-style diet
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