987 research outputs found
Collicular Responses to the Frequency Modulated Final Part of Echolocation Sounds in Rhinolophusferrum equinum
Collicular evoked potentials in Rhinolophus ferrum equinum show
very prominent responses to the final frequency modulated part of a acoustic
stimulus, simulating the natural echolocation sound
Rotational Stocking with Virtual Fences: Effects on Grassland Diet Digestibility, Livestock Performance and Stress Levels of Heifers
Virtual fencing is an innovative technology for simplified, less laborious dynamic grazing management and remote animal monitoring. The effect of this novel technology on animal welfare is still a matter of debate. Previous research suggests no differences in stress experience responses of cattle between the two fencing systems on continuously stocked pastures. This study investigated differences in diet organic matter digestibility, livestock performance and fecal cortisol metabolite concentrations of heifers on pastures in a rotational grazing system, fenced with a virtual fence (Nofence, Batnfjordsøra Norway) compared to heifers fenced with a traditional electric wire fence. The study was conducted in 8 weeks from July to September 2021 using 32 heifers divided into four groups allocated to the two fencing systems (two replicates). The experimental pasture of each group was subdivided into four paddocks for rotational grazing. Fecal samples were collected the first day and last day on pasture of each rotation period. Grassland herbage samples were taken by hand plucking pre- and post-grazing and analyzed using near infrared reflectance spectroscopy. Heifers were weighed prior to and after each rotation. The results suggest that no differences occur between the two fencing treatments with respect to diet digestibility, livestock performance or stress level, pointing at no trade-off to livestock performance or animal welfare when using virtual fencing
Phenotypic differences between dermal fibroblasts from different body sites determine their responses to tension and TGFβ1
BACKGROUND: Wounds in the nonglabrous skin of keloid-prone individuals tend to cause large disordered accumulations of collagen which extend beyond the original margins of the wound. In addition to abnormalities in keloid fibroblasts, comparison of dermal fibroblasts derived from nonwounded glabrous or nonglabrous skin revealed differences that may account for the observed location of keloids. METHODS: Fibroblast apoptosis and the cellular content of α-smooth-muscle actin, TGFβ1 receptorII and ED-A fibronectin were estimated by FACS analysis. The effects of TGFβ1 and serum were examined. RESULTS: In monolayer cultures non-glabrous fibroblasts were slower growing, had higher granularity and accumulated more α-smooth-muscle actin than fibroblasts from glabrous tissues. Keloid fibroblasts had the highest level of α-smooth-muscle actin in parallel with their expression level of ED-A fibronectin. TGFβ1 positively regulated α-smooth-muscle actin expression in all fibroblast cultures, although its effects on apoptosis in fibroblasts from glabrous and non-glabrous tissues were found to differ. The presence of collagen I in the ECM resulted in reduction of α-smooth-muscle actin. A considerable percentage of the apoptotic fibroblasts in attached gels were α-smooth-muscle actin positive. The extent of apoptosis correlated positively with increased cell and matrix relaxation. TGFβ1 was unable to overcome this apoptotic effect of matrix relaxation. CONCLUSION: The presence of myofibroblasts and the apoptosis level can be regulated by both TGFβ1 and by the extracellular matrix. However, reduction of tension in the matrix is the critical determinant. This predicts that the tension in the wound bed determines the type of scar at different body sites
Elastic interactions of active cells with soft materials
Anchorage-dependent cells collect information on the mechanical properties of
the environment through their contractile machineries and use this information
to position and orient themselves. Since the probing process is anisotropic,
cellular force patterns during active mechanosensing can be modelled as
anisotropic force contraction dipoles. Their build-up depends on the mechanical
properties of the environment, including elastic rigidity and prestrain. In a
finite sized sample, it also depends on sample geometry and boundary conditions
through image strain fields. We discuss the interactions of active cells with
an elastic environment and compare it to the case of physical force dipoles.
Despite marked differences, both cases can be described in the same theoretical
framework. We exactly solve the elastic equations for anisotropic force
contraction dipoles in different geometries (full space, halfspace and sphere)
and with different boundary conditions. These results are then used to predict
optimal position and orientation of mechanosensing cells in soft material.Comment: Revtex, 38 pages, 8 Postscript files included; revised version,
accepted for publication in Phys. Rev.
Amine functionalization of cholecyst-derived extracellular matrix with generation 1 PAMAM dendrimer
This document is the unedited author's version of a Submitted Work that was subsequently accepted for publication in Biomacromolecules, copyright © American Chemical Society after peer review. To access the final edited and published work, see http://pubs.acs.org/doi/pdf/10.1021/bm701055k.A method to functionalize cholecyst-derived extracellular matrix (CEM) with free amine groups was established in an attempt to improve its potential for tethering of bioactive molecules. CEM was incorporated with Generation-1 polyamidoamine (G1 PAMAM) dendrimer by using N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide and N-hydroxysuccinimide cross-linking system. The nature of incorporation of PAMAM dendrimer was evaluated using shrink temperature measurements, Fourier transform infrared (FTIR) assessment, ninhydrin assay, and swellability. The effects of PAMAM incorporation on mechanical and degradation properties of CEM were evaluated using a uniaxial mechanical test and collagenase degradation assay, respectively. Ninhydrin assay and FTIR assessment confirmed the presence of increasing free amine groups with increasing quantity of PAMAM in dendrimer-incorporated CEM (DENCEM) scaffolds. The amount of dendrimer used was found to be critical in controlling scaffold degradation, shrink temperature, and free amine content. Cell culture studies showed that fibroblasts seeded on DENCEM maintained their metabolic activity and ability to proliferate in vitro. In addition, fluorescence cell staining and scanning electron microscopy analysis of cell-seeded DENCEM showed preservation of normal fibroblast morphology and phenotype
Recommended from our members
Consistent phenological shifts in the making of a biodiversity hotspot: the Cape flora
Background
The best documented survival responses of organisms to past climate change on short (glacial-interglacial) timescales are distributional shifts. Despite ample evidence on such timescales for local adaptations of populations at specific sites, the long-term impacts of such changes on evolutionary significant units in response to past climatic change have been little documented. Here we use phylogenies to reconstruct changes in distribution and flowering ecology of the Cape flora - South Africa's biodiversity hotspot - through a period of past (Neogene and Quaternary) changes in the seasonality of rainfall over a timescale of several million years.
Results
Forty-three distributional and phenological shifts consistent with past climatic change occur across the flora, and a comparable number of clades underwent adaptive changes in their flowering phenology (9 clades; half of the clades investigated) as underwent distributional shifts (12 clades; two thirds of the clades investigated). Of extant Cape angiosperm species, 14-41% have been contributed by lineages that show distributional shifts consistent with past climate change, yet a similar proportion (14-55%) arose from lineages that shifted flowering phenology.
Conclusions
Adaptive changes in ecology at the scale we uncover in the Cape and consistent with past climatic change have not been documented for other floras. Shifts in climate tolerance appear to have been more important in this flora than is currently appreciated, and lineages that underwent such shifts went on to contribute a high proportion of the flora's extant species diversity. That shifts in phenology, on an evolutionary timescale and on such a scale, have not yet been detected for other floras is likely a result of the method used; shifts in flowering phenology cannot be detected in the fossil record
MOLECULAR STRUCTURE OF THE EPIDERMAL EXTRACELLULAR SPACES
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65966/1/j.1365-4362.1979.tb01946.x.pd
Tolerability of adjunctive eslicarbazepine acetate according to concomitant lamotrigine or carbamazepine use: A subgroup analysis of three phase III trials in adults with focal (partial-onset) seizures.
To evaluate and compare the effects of concomitant lamotrigine (LTG) or carbamazepine (CBZ) on the incidence of treatment-emergent adverse events (TEAEs) in patients taking adjunctive eslicarbazepine acetate (ESL) for focal (partial-onset) seizures (FS).
These post-hoc analyses of data pooled from three randomized, double-blind, placebo-controlled studies of adjunctive ESL (BIA-2093-301, -302 and -304) included adults (≥16 years) with FS refractory to 1-3 antiepileptic drugs (AEDs). Patients were randomized equally to placebo, ESL 400 mg (Studies 301 and 302 only), 800 mg, or 1200 mg once daily (8-week baseline, 2-week titration, and 12-week maintenance periods). TEAEs, TEAEs leading to discontinuation, and serious AEs (SAEs) were evaluated in patients taking, or not taking, LTG (excluding those taking CBZ or phenytoin [PHT]; i.e., the +LTG and -LTG/-CBZ subgroups), or CBZ (excluding those taking LTG or PHT; i.e., the +CBZ and -LTG/-CBZ subgroups) at baseline.
LTG was used concomitantly by 248 patients (+LTG; placebo, n = 81; ESL, n = 167) and CBZ by 613 patients (+CBZ; placebo, n = 172; ESL, n = 441); 361 patients were taking neither LTG nor CBZ (-LTG/-CBZ; placebo, n = 109; ESL, n = 252). The overall incidence of TEAEs with ESL (any dose) was numerically higher for +CBZ (77%) than for +LTG (73%) or -LTG/-CBZ (68%; statistical significance not tested). Among patients taking ESL, dizziness, diplopia, and vomiting were reported more frequently in the +CBZ subgroup (30%, 14%, and 10%, respectively) than in the +LTG (16%, 8%, 5%) or -LTG/-CBZ (11%, 3%, 5%) subgroups. The overall incidence of TEAEs leading to discontinuation with ESL was higher for +CBZ (21%) than for +LTG (13%) or -LTG/-CBZ (15%). Dizziness leading to discontinuation with ESL was reported more frequently in the +CBZ subgroup than in the +LTG or -LTG/-CBZ subgroups (9%, 3%, and 3%, respectively). The overall incidence of SAEs in patients taking ESL was comparable across subgroups (+LTG, 5%; +CBZ, 6%; -LTG/-CBZ, 5%). The results were similar when evaluating placebo-adjusted incidences.
There was a potential pharmacodynamic interaction between AEDs with a putatively similar mechanism of action, with a seemingly lesser interaction between ESL and LTG versus ESL and CBZ. If combining ESL with LTG or CBZ, clinicians should be aware of the potential risk for an increased incidence of TEAEs typically associated with voltage-gated sodium channel inhibitors (e.g., dizziness, blurred vision, vertigo, diplopia, headache, or vomiting)
Filterability of staphylococcal species through membrane filters following application of stressors
<p>Abstract</p> <p>Background</p> <p>Passage of bacterial cells through filter pores has been reported for a number of bacterial species. In this investigation, we tested the filterability of staphylococcal cultures that were exposed to several environmental stress conditions by passing them through 0.22 and 0.45 μm sterile filters, which are industry standards.</p> <p>Findings</p> <p>Results showed repeated passage of viable staphylococcal cells through both pore sizes, although more passage was seen through the 0.45 μm pore size. Of the three staphylococcal species, <it>S. lugdunensis </it>showed the best passage at relatively higher numbers regardless of the treatment, while both <it>S. aureus </it>and <it>S. epidermidis </it>showed limited passage or complete inhibition.</p> <p>Conclusion</p> <p>The data showed that staphylococcal bacteria were capable of passing through sterile filters in a viable state. There was better passage through 0.45 μm sterile filters than through the 0.22 μm sterile filters. Application of a stress condition did not appear to enhance filterability of these bacterial cultures.</p
- …