2,056 research outputs found
Investigations into the Sarcomeric Protein and Ca2+-Regulation Abnormalities Underlying Hypertrophic Cardiomyopathy in Cats (Felix catus).
Hypertrophic cardiomyopathy (HCM) is the most common single gene inherited cardiomyopathy. In cats (Felix catus) HCM is even more prevalent and affects 16% of the outbred population and up to 26% in pedigree breeds such as Maine Coon and Ragdoll. Homozygous MYBPC3 mutations have been identified in these breeds but the mutations in other cats are unknown. At the clinical and physiological level feline HCM is closely analogous to human HCM but little is known about the primary causative mechanism. Most identified HCM causing mutations are in the genes coding for proteins of the sarcomere. We therefore investigated contractile and regulatory proteins in left ventricular tissue from 25 cats, 18 diagnosed with HCM, including a Ragdoll cat with a homozygous MYBPC3 R820W, and 7 non-HCM cats in comparison with human HCM (from septal myectomy) and donor heart tissue. Myofibrillar protein expression was normal except that we observed 20–44% MyBP-C haploinsufficiency in 5 of the HCM cats. Troponin extracted from 8 HCM and 5 non-HCM cat hearts was incorporated into thin filaments and studied by in vitro motility assay. All HCM cat hearts had a higher (2.06 ± 0.13 fold) Ca2+-sensitivity than non-HCM cats and, in all the HCM cats, Ca2+-sensitivity was not modulated by troponin I phosphorylation. We were able to restore modulation of Ca2+-sensitivity by replacing troponin T with wild-type protein or by adding 100 μM Epigallocatechin 3-gallate (EGCG). These fundamental regulatory characteristics closely mimic those seen in human HCM indicating a common molecular mechanism that is independent of the causative mutation. Thus, the HCM cat is a potentially useful large animal model
Ascertaining the Core Collapse Supernova Mechanism: An Emerging Picture?
Here we present the results from two sets of simulations, in two and three
spatial dimensions. In two dimensions, the simulations include multifrequency
flux-limited diffusion neutrino transport in the "ray-by-ray-plus"
approximation, two-dimensional self gravity in the Newtonian limit, and nuclear
burning through a 14-isotope alpha network. The three-dimensional simulations
are model simulations constructed to reflect the post stellar core bounce
conditions during neutrino shock reheating at the onset of explosion. They are
hydrodynamics-only models that focus on critical aspects of the shock stability
and dynamics and their impact on the supernova mechanism and explosion. In two
dimensions, we obtain explosions (although in one case weak) for two
progenitors (11 and 15 Solar mass models). Moreover, in both cases the
explosion is initiated when the inner edge of the oxygen layer accretes through
the shock. Thus, the shock is not revived while in the iron core, as previously
discussed in the literature. The three-dimensional studies of the development
of the stationary accretion shock instability (SASI) demonstrate the
fundamentally new dynamics allowed when simulations are performed in three
spatial dimensions. The predominant l=1 SASI mode gives way to a stable m=1
mode, which in turn has significant ramifications for the distribution of
angular momentum in the region between the shock and proto-neutron star and,
ultimately, for the spin of the remnant neutron star. Moreover, the
three-dimensional simulations make clear, given the increased number of degrees
of freedom, that two-dimensional models are severely limited by artificially
imposed symmetries.Comment: 9 pages, 3 figure
Differential nuclear localization of complexes may underlie in vivo intrabody efficacy in Huntington's disease.
Intrabodies offer attractive options for manipulating the protein misfolding that triggers neurodegenerative diseases. In Huntington's disease, where the expanded polyglutamine tract in the extreme N-terminal region of huntingtin exon1 misfolds, two lead intrabodies have been selected against an adjacent peptide, using slightly different approaches. Both are effective at preventing aggregation of a reporter fragment in transient co-transfection assays. However, after intracranial delivery to mutant mouse brains, VL12.3, which is mainly localized to the nucleus, appears to accelerate the mutant phenotype, while C4 scFv, which is largely cytoplasmic, shows partial phenotypic correction. This comparison highlights parameters that could inform intrabody therapeutics for multiple proteostatic diseases.This is the final published version. It's also available from OUP at http://peds.oxfordjournals.org/content/27/10/359.full.html
Phototesting and photoprotection in LE
Photosensitivity and induction of skin lesions following UV radiation is a common problem of patients with cutaneous and systemic forms of lupus erythematosus. The detrimental effect of UV radiation to patients with lupus erythematosus was already recognized in the last century. Skin lesions can now be provoked under standardized conditions allowing the diagnosis and classification of patients with photosensitive disorders. The aim of this review is to give an overview on the history, test procedure and test results in patients with lupus erythematosus
Neutrino-driven supernovae: Boltzmann neutrino transport and the explosion mechanism
Core-collapse supernovae are, despite their spectacular visual display,
neutrino events. Virtually all of the 10^53 ergs of gravitational binding
energy released in the formation of the nascent neutron star is carried away in
the form of neutrinos and antineutrinos of all three flavors, and these
neutrinos are primarily responsible for powering the explosion. This mechanism
depends sensitively on the neutrino transport between the neutrinospheres and
the shock. In light of this, we have performed a comparison of multigroup
Boltzmann neutrino transport (MGBT) and multigroup flux-limited diffusion
(MGFLD) in post-core bounce environments. Differences in the mean inverse flux
factors, luminosities, and RMS energies translate to heating rates that are up
to 2 times larger for Boltzmann transport, with net cooling rates below the
gain radius that are typically 0.8 times the MGFLD rates. These differences are
greatest at earlier postbounce times for a given progenitor mass, and for a
given postbounce time, greater for greater progenitor mass. The increased
differences with increased progenitor mass suggest that the net heating
enhancement from MGBT is potentially robust and self-regulated.Comment: 7 pages, 2 figures, 1 table; LaTex using iopconf.sty; To appear in:
Proceedings of The Second Oak Ridge Symposium on Atomic & Nuclear
Astrophysic
Rapid Communication: Epidermal Growth Factor Maps to Pig Chromosome 8
Source and Description of Primers. Primers were designed from published sheep epidermal growth factor ( EGF) sequence (GenBank accession no. U36428) and were used to amplify across intron 3 of the EGF gene from porcine genomic DNA. Of sequences produced, 84 bp showed 82.1% identity to sheep EGF exon 3 and 81.0% to human EFG exon 3. For exon 4, the 75 bp showed 82.3% identity to sheep EGF exon 4 and 77.3% identity to human EGF exon 4. These sequences were further used to design pigspecific primers and have been submitted to GenBank (accession nos. AF079768 and AF079769)
- …