45 research outputs found
Liposomal Packaging Generates Wnt Protein with In Vivo Biological Activity
Wnt signals exercise strong cell-biological and regenerative effects of considerable therapeutic value. There are, however, no specific Wnt agonists and no method for in vivo delivery of purified Wnt proteins. Wnts contain lipid adducts that are required for activity and we exploited this lipophilicity by packaging purified Wnt3a protein into lipid vesicles. Rather than being encapsulated, Wnts are tethered to the liposomal surface, where they enhance and sustain Wnt signaling in vitro. Molecules that effectively antagonize soluble Wnt3a protein but are ineffective against the Wnt3a signal presented by a cell in a paracrine or autocrine manner are also unable to block liposomal Wnt3a activity, suggesting that liposomal packaging mimics the biological state of active Wnts. When delivered subcutaneously, Wnt3a liposomes induce hair follicle neogenesis, demonstrating their robust biological activity in a regenerative context
Lateralization of mesial temporal lobe epilepsy with chronic ambulatory electrocorticography
OBJECTIVE: Patients with suspected mesial temporal lobe (MTL) epilepsy typically undergo inpatient video-electroencephalography (EEG) monitoring with scalp and/or intracranial electrodes for 1 to 2 weeks to localize and lateralize the seizure focus or foci. Chronic ambulatory electrocorticography (ECoG) in patients with MTL epilepsy may provide additional information about seizure lateralization. This analysis describes data obtained from chronic ambulatory ECoG in patients with suspected bilateral MTL epilepsy in order to assess the time required to determine the seizure lateralization and whether this information could influence treatment decisions.
METHODS: Ambulatory ECoG was reviewed in patients with suspected bilateral MTL epilepsy who were among a larger cohort with intractable epilepsy participating in a randomized controlled trial of responsive neurostimulation. Subjects were implanted with bilateral MTL leads and a cranially implanted neurostimulator programmed to detect abnormal interictal and ictal ECoG activity. ECoG data stored by the neurostimulator were reviewed to determine the lateralization of electrographic seizures and the interval of time until independent bilateral MTL electrographic seizures were recorded.
RESULTS: Eighty-two subjects were implanted with bilateral MTL leads and followed for 4.7 years on average (median 4.9 years). Independent bilateral MTL electrographic seizures were recorded in 84%. The average time to record bilateral electrographic seizures in the ambulatory setting was 41.6 days (median 13 days, range 0-376 days). Sixteen percent had only unilateral electrographic seizures after an average of 4.6 years of recording.
SIGNIFICANCE: About one third of the subjects implanted with bilateral MTL electrodes required >1 month of chronic ambulatory ECoG before the first contralateral MTL electrographic seizure was recorded. Some patients with suspected bilateral MTL seizures had only unilateral electrographic seizures. Chronic ambulatory ECoG in patients with suspected bilateral MTL seizures provides data in a naturalistic setting, may complement data from inpatient video-EEG monitoring, and can contribute to treatment decisions
SN 2022crv: IIb, Or Not IIb: That is the Question
We present optical and near-infrared observations of SN~2022crv, a stripped
envelope supernova in NGC~3054, discovered within 12 hrs of explosion by the
Distance Less Than 40 Mpc Survey. We suggest SN~2022crv is a transitional
object on the continuum between SNe Ib and SNe IIb. A high-velocity hydrogen
feature (20,000 -- 16,000 ) was conspicuous in
SN~2022crv at early phases, and then quickly disappeared around maximum light.
By comparing with hydrodynamic modeling, we find that a hydrogen envelope of
\msun{} can reproduce the behaviour of the hydrogen feature
observed in SN~2022crv. The early light curve of SN~2022crv did not show
envelope cooling emission, implying that SN~2022crv had a compact progenitor
with extremely low amount of hydrogen. The analysis of the nebular spectra
shows that SN~2022crv is consistent with the explosion of a He star with a
final mass of 4.5 -- 5.6 \msun{} that has evolved from a 16 -- 22
\msun{} zero-age main sequence star in a binary system with about 1.0 -- 1.7
\msun{} of oxygen finally synthesized in the core. The high metallicity at the
supernova site indicates that the progenitor experienced a strong stellar wind
mass loss. In order to retain a small amount of residual hydrogen at such a
high metallicity, the initial orbital separation of the binary system is likely
larger than 1000~. The near-infrared spectra of SN~2022crv
show a unique absorption feature on the blue side of He I line at
1.005~m. This is the first time that such a feature has been
observed in a Type Ib/IIb, and could be due to \ion{Sr}{2}. Further detailed
modelling on SN~2022crv can shed light on the progenitor and the origin of the
mysterious absorption feature in the near infrared.Comment: 33 pages, 23 figures, submitted to Ap
SN 2017gmr: An Energetic Type II-P Supernova with Asymmetries
We present high-cadence UV, optical, and near-infrared data on the luminous Type II-P supernova SN2017gmr from hours after discovery through the first 180 days. SN2017gmr does not show signs of narrow, high-ionization emission lines in the early optical spectra, yet the optical light-curve evolution suggests that an extra energy source from circumstellar medium (CSM) interaction must be present for at least 2 days after explosion. Modeling of the early light curve indicates a ∼500 Re progenitor radius, consistent with a rather compact red supergiant, and latetime luminosities indicate that up to 0.130±0.026 Me of 56Ni are present, if the light curve is solely powered by radioactive decay, although the 56Ni mass may be lower if CSM interaction contributes to the post-plateau luminosity. Prominent multipeaked emission lines of Hα and [O I] emerge after day 154, as a result of either an asymmetric explosion or asymmetries in the CSM. The lack of narrow lines within the first 2 days of explosion in the likely presence of CSM interaction may be an example of close, dense, asymmetric CSM that is quickly enveloped by the spherical supernova ejecta
The SPIRITS Sample of Luminous Infrared Transients: Uncovering Hidden Supernovae and Dusty Stellar Outbursts in Nearby Galaxies
We present a systematic study of the most luminous (M IR [Vega magnitudes] brighter than −14) infrared (IR) transients discovered by the SPitzer InfraRed Intensive Transients Survey (SPIRITS) between 2014 and 2018 in nearby galaxies (D 12) show multiple, luminous IR outbursts over several years and have directly detected, massive progenitors in archival imaging. With analyses of extensive, multiwavelength follow-up, we suggest the following possible classifications: five obscured core-collapse supernovae (CCSNe), two erupting massive stars, one luminous red nova, and one intermediate-luminosity red transient. We define a control sample of all optically discovered transients recovered in SPIRITS galaxies and satisfying the same selection criteria. The control sample consists of eight CCSNe and one Type Iax SN. We find that 7 of the 13 CCSNe in the SPIRITS sample have lower bounds on their extinction of 2 < A V < 8. We estimate a nominal fraction of CCSNe in nearby galaxies that are missed by optical surveys as high as (90% confidence). This study suggests that a significant fraction of CCSNe may be heavily obscured by dust and therefore undercounted in the census of nearby CCSNe from optical searches
Strong Carbon Features and a Red Early Color in the Underluminous Type Ia SN 2022xkq
We present optical, infrared, ultraviolet, and radio observations of SN
2022xkq, an underluminous fast-declining type Ia supernova (SN Ia) in NGC 1784
( Mpc), from to 180 days after explosion. The
high-cadence observations of SN 2022xkq, a photometrically transitional and
spectroscopically 91bg-like SN Ia, cover the first days and weeks following
explosion which are critical to distinguishing between explosion scenarios. The
early light curve of SN 2022xkq has a red early color and exhibits a flux
excess which is more prominent in redder bands; this is the first time such a
feature has been seen in a transitional/91bg-like SN Ia. We also present 92
optical and 19 near-infrared (NIR) spectra, beginning 0.4 days after explosion
in the optical and 2.6 days after explosion in the NIR. SN 2022xkq exhibits a
long-lived C I 1.0693 m feature which persists until 5 days post-maximum.
We also detect C II 6580 in the pre-maximum optical spectra. These
lines are evidence for unburnt carbon that is difficult to reconcile with the
double detonation of a sub-Chandrasekhar mass white dwarf. No existing
explosion model can fully explain the photometric and spectroscopic dataset of
SN 2022xkq, but the considerable breadth of the observations is ideal for
furthering our understanding of the processes which produce faint SNe Ia.Comment: 38 pages, 16 figures, accepted for publication in ApJ, the figure 15
input models and synthetic spectra are now available at
https://zenodo.org/record/837925
Recommended from our members
A Panchromatic View of the Restless Sn 2009ip Reveals the Explosive Ejection of a Massive Star Envelope
The double explosion of SN 2009ip in 2012 raises questions about our understanding of the late stages of massive star evolution. Here we present a comprehensive study of SN 2009ip during its remarkable rebrightenings. High-cadence photometric and spectroscopic observations from the GeV to the radio band obtained from a variety of ground-based and space facilities (including the Very Large Array, Swift, Fermi, Hubble Space Telescope, and XMM) constrain SN 2009ip to be a low energy (E ~ 1050 erg for an ejecta mass ~0.5 M ☉) and asymmetric explosion in a complex medium shaped by multiple eruptions of the restless progenitor star. Most of the energy is radiated as a result of the shock breaking out through a dense shell of material located at ~5 × 1014 cm with M ~ 0.1 M ☉, ejected by the precursor outburst ~40 days before the major explosion. We interpret the NIR excess of emission as signature of material located further out, the origin of which has to be connected with documented mass-loss episodes in the previous years. Our modeling predicts bright neutrino emission associated with the shock break-out if the cosmic-ray energy is comparable to the radiated energy. We connect this phenomenology with the explosive ejection of the outer layers of the massive progenitor star, which later interacted with material deposited in the surroundings by previous eruptions. Future observations will reveal if the massive luminous progenitor star survived. Irrespective of whether the explosion was terminal, SN 2009ip brought to light the existence of new channels for sustained episodic mass loss, the physical origin of which has yet to be identified.Astronom
Genetic determinants of risk in pulmonary arterial hypertension: international genome-wide association studies and meta-analysis
Background Rare genetic variants cause pulmonary arterial hypertension, but the contribution of common genetic
variation to disease risk and natural history is poorly characterised. We tested for genome-wide association for pulmonary
arterial hypertension in large international cohorts and assessed the contribution of associated regions to outcomes.
Methods We did two separate genome-wide association studies (GWAS) and a meta-analysis of pulmonary arterial
hypertension. These GWAS used data from four international case-control studies across 11744 individuals with
European ancestry (including 2085 patients). One GWAS used genotypes from 5895 whole-genome sequences and
the other GWAS used genotyping array data from an additional 5849 individuals. Cross-validation of loci reaching
genome-wide significance was sought by meta-analysis. Conditional analysis corrected for the most significant variants
at each locus was used to resolve signals for multiple associations. We functionally annotated associated variants and
tested associations with duration of survival. All-cause mortality was the primary endpoint in survival analyses.
Findings A locus near SOX17 (rs10103692, odds ratio 1·80 [95% CI 1·55–2·08], p=5·13×10–
¹⁵) and a second locus in
HLA-DPA1 and HLA-DPB1 (collectively referred to as HLA-DPA1/DPB1 here; rs2856830, 1·56 [1·42–1·71],
p=7·65×10–
²⁰) within the class II MHC region were associated with pulmonary arterial hypertension. The SOX17 locus
had two independent signals associated with pulmonary arterial hypertension (rs13266183, 1·36 [1·25–1·48],
p=1·69×10–
¹²; and rs10103692). Functional and epigenomic data indicate that the risk variants near SOX17 alter gene
regulation via an enhancer active in endothelial cells. Pulmonary arterial hypertension risk variants determined
haplotype-specific enhancer activity, and CRISPR-mediated inhibition of the enhancer reduced SOX17 expression. The
HLA-DPA1/DPB1 rs2856830 genotype was strongly associated with survival. Median survival from diagnosis in
patients with pulmonary arterial hypertension with the C/C homozygous genotype was double (13·50 years [95% CI
12·07 to >13·50]) that of those with the T/T genotype (6·97 years [6·02–8·05]), despite similar baseline disease severity.
Interpretation This is the first study to report that common genetic variation at loci in an enhancer near SOX17 and in
HLA-DPA1/DPB1 is associated with pulmonary arterial hypertension. Impairment of SOX17 function might be more
common in pulmonary arterial hypertension than suggested by rare mutations in SOX17. Further studies are needed
to confirm the association between HLA typing or rs2856830 genotyping and survival, and to determine whether HLA
typing or rs2856830 genotyping improves risk stratification in clinical practice or trials.
Funding UK NIHR, BHF, UK MRC, Dinosaur Trust, NIH/NHLBI, ERS, EMBO, Wellcome Trust, EU, AHA,
ACClinPharm, Netherlands CVRI, Dutch Heart Foundation, Dutch Federation of UMC, Netherlands OHRD and
RNAS, German DFG, German BMBF, APH Paris, INSERM, Université Paris-Sud, and French ANR
Chronic Volar Lunate Dislocation Resulting in Carpal Tunnel Syndrome: A Case Report
Lunate dislocations are rare injuries caused by highenergy trauma disrupting the ligamentous restraints that connect the lunate to the carpus. We describe a case of missed volar lunate dislocation 10 years after the initial injury. The patient presented to our clinic with symptoms of carpal tunnel syndrome after falling on an outstretched arm. He had increasing paresthesias in his median nerve territory and underwent a proximal row carpectomy with release of the transverse carpal ligament. At 2 years postoperatively, successful outcomes were noted with an 80° arc of motion of the carpus and complete resolution of carpal tunnel symptoms. Although rare, chronic lunate dislocations should be considered as a cause of carpal tunnel syndrome in patients with considerable traumatic injuries of the wrist. Careful inspection is essential to ensure this diagnosis is not missed