1,816 research outputs found
A study of the selective hydroconversion of biocarboxylic acids to bioalcohols over novel indium-nickel/zeolite catalysts using octanoic acid as model reactant
Octanoic acid (OA) was hydrotreated in a flow-through reactor at 21 bar total pressure and 240-340 °C over supported metal catalysts prepared from Ni-zeolites (A, X, P) by indium modification. The Ni-zeolites were activated first in H2 flow at 21 bar and 450 °C. While a fraction of the nickel got fully reduced, the zeolite structure became partially destructed. However, some nickel cations remained unreduced, therefore a large fraction of the crystalline zeolite structure was retained. The indium modification of the reduced Ni-zeolites generated bimetallic NiIn/Ni,H-zeolite catalysts having higher stability, hydroconversion activity, octanol selectivity, and lower hydrodecarbonylation activity than the parent partially destructed Ni-zeolite and the Adkins-type catalysts, commercially applied for the conversion of fatty acids to alcohols. © 2013 Akadémiai Kiadó, Budapest, Hungary
FGFR2-activating mutations disrupt cell polarity to potentiate migration and invasion in endometrial cancer cell models
Fibroblast growth factor receptors (FGFRs) are a family of receptor tyrosine kinases that control a diverse range of biological processes during development and in adult tissues. We recently reported that somatic FGFR2 mutations are associated with shorter survival in endometrial cancer. However, little is known about how these FGFR2 mutations contribute to endometrial cancer metastasis. Here, we report that expression of the activating mutations FGFR2N550K and FGFR2Y376C in an endometrial cancer cell model induce Golgi fragmentation, and loss of polarity and directional migration. In mutant FGFR2-expressing cells, this was associated with an inability to polarise intracellular pools of FGFR2 towards the front of migrating cells. Such polarization defects were exacerbated in three-dimensional culture, where FGFR2 mutant cells were unable to form well-organised acini, instead undergoing exogenous ligand-independent invasion. Our findings uncover collective cell polarity and invasion as common targets of disease-associated FGFR2 mutations that lead to poor outcome in endometrial cancer patients
Role of the α1 blocker doxazosin in alcoholism: a proof-of-concept randomized controlled trial
Evidence suggests that the norepinephrine system represents an important treatment target for alcohol dependence (AD) and the α1-blocker prazosin may reduce alcohol drinking in rodents and alcoholic patients. The α1-blocker doxazosin demonstrates a more favorable pharmacokinetic profile than prazosin, but has never been studied for AD. A double-blind placebo-controlled randomized clinical trial was conducted in AD individuals seeking outpatient treatment. Doxazosin or matched placebo was titrated to 16 mg/day (or maximum tolerable dose). Drinks per week (DPW) and heavy drinking days (HDD) per week were the primary outcomes. Family history density of alcoholism (FHDA), severity of AD and gender were a priori moderators. Forty-one AD individuals were randomized, 30 (doxazosin = 15) completed the treatment phase and 28 (doxazosin = 14) also completed the follow-up. There were no significant differences between groups on DPW and HDD per week. With FHDA as a moderator, there were significant FHDA × medication interactions for both DPW (pcorrected = 0.001, d = 1.18) and HDD (pcorrected = 0.00009, d = 1.30). Post hoc analyses revealed that doxazosin significantly reduced alcohol drinking in AD patients with high FHDA and by contrast increased drinking in those with low FHDA. Doxazosin may be effective selectively in AD patients with high FHDA. This study provides preliminary evidence for personalized medicine using α1-blockade to treat AD. However, confirmatory studies are required
Accountability for SRHR in the context of the COVID-19 pandemic
Governments and international organisations are focused on COVID-19 crisis decision-making. As a result, global and national health governance contexts are changing dramatically, as are the social and political determinants of sexual and reproductive health and rights (SRHR). Various gender dimensions of the pandemic are clear. While initial data suggest that men are more vulnerable to COVID-19 related mortality, in many high, middle, and low-income countries, the “essential workers” and informal workers who are disproportionately exposed are disproportionately lower social status women. (Boniol et al., 2019; Wenham et al., 2020) Intersecting injustices mean that certain disadvantaged groups are particularly hard hit. (Morgan & Davies, 2020) They are left to reconcile the often-incompatible demands of precarious jobs, potential exposure to COVID-19, the stress of caring responsibilities under lockdown and, particularly for women, increased isolation exacerbating Gender-Based Violence (GBV)
Generic Mechanism of Emergence of Amyloid Protofilaments from Disordered Oligomeric aggregates
The presence of oligomeric aggregates, which is often observed during the
process of amyloid formation, has recently attracted much attention since it
has been associated with neurodegenerative conditions such as Alzheimer's and
Parkinson's diseases. We provide a description of a sequence-indepedent
mechanism by which polypeptide chains aggregate by forming metastable
oligomeric intermediate states prior to converting into fibrillar structures.
Our results illustrate how the formation of ordered arrays of hydrogen bonds
drives the formation of beta-sheets within the disordered oligomeric aggregates
that form early under the effect of hydrophobic forces. Initially individual
beta-sheets form with random orientations, which subsequently tend to align
into protofilaments as their lengths increases. Our results suggest that
amyloid aggregation represents an example of the Ostwald step rule of first
order phase transitions by showing that ordered cross-beta structures emerge
preferentially from disordered compact dynamical intermediate assemblies.Comment: 14 pages, 4 figure
Chronic y-secretase inhibition reduces amyloid plaque-associated instability of pre- and postsynaptic structures
The loss of synapses is a strong histological correlate of the cognitive decline in Alzheimer’s disease (AD). Amyloid bpeptide (Ab), a cleavage product of the amyloid precursor protein (APP), exerts detrimental effects on synapses, a process thought to be causally related to the cognitive deficits in AD. Here, we used in vivo two-photon microscopy to characterize the dynamics of axonal boutons and dendritic spines in APP/Presenilin 1 (APPswe/PS1L166P)–green fluorescent protein (GFP) transgenic mice. Time-lapse imaging over 4 weeks revealed a pronounced, concerted instability of pre- and postsynaptic structures within the vicinity of amyloid plaques. Treatment with a novel sulfonamide-type g-secretase inhibitor (GSI) attenuated the formation and growth of new plaques and, most importantly, led to a normalization of the enhanced dynamics of synaptic structures close to plaques. GSI treatment did neither affect spines and boutons distant from plaques in amyloid precursor protein/presenilin 1-GFP (APPPS1-GFP) nor those in GFP-control mice, suggesting no obvious neuropathological side effects of the drug
Decoupling of optoelectronic properties from morphological changes in sodium treated kesterite thin film solar cells
Sodium is typically used during the synthesis of kesterite thin films to enhance the performance of solar cells. As sodium tends to affect grain growth and morphology, it is difficult to analyse solely the electronic effects of sodium as dopant. To decouple the structural and electronic effects from each other, two processes were designed in this work to successfully incorporate sodium into a vacuum-processed Cu2ZnSnSe4absorber without changing the morphology. A thin layer of NaF is deposited before precursor deposition (Pre-NaF) or after absorber synthesis to undergo a post deposition treatment (NaF-PDT). While composition and distribution of matrix elements remain unchanged, the sodium concentration is increased upon sodium treatment up to 140 ppm as measured by inductively coupled plasma mass spectrometry. X-ray photoelectron spectroscopy showed that the surface composition was not altered. Within its detection limit, sodium was not present at the absorber surface. For a Pre-NaF sample measured with atom probe tomography a sodium concentration of 30 ppm was measured in a grain, suggesting that sodium might segregate at grain boundaries. The additional sodium content in the film leads to an increased acceptor concentration, which results in improved open-circuit voltage and fill factor.Financial support from the Swiss National Science Foundation (SNF)
in the network of the Indo-Swiss Joint Research Programme (ISJRP)
[IZLIZ2_157140/1] is gratefully acknowledged. T. Schwarz is grateful for the support of the
German Research Foundation (DFG) [Contract GA 2450/1-1]. R.
Caballero acknowledges financial support from Spanish MINECO
within the Ramón y Cajal program [RYC-2011-08521], MINECO project
WINCOST [ENE2016-80788-C5-2-R] and from Spanish Ministry of
Education, Culture and Sport within the José Castillejo program [CAS
15/00070
Higher CSF sTREM2 attenuates ApoE4-related risk for cognitive decline and neurodegeneration
BACKGROUND: The Apolipoprotein E ε4 allele (i.e. ApoE4) is the strongest genetic risk factor for sporadic Alzheimer's disease (AD). TREM2 (i.e. Triggering receptor expressed on myeloid cells 2) is a microglial transmembrane protein brain that plays a central role in microglia activation in response to AD brain pathologies. Whether higher TREM2-related microglia activity modulates the risk to develop clinical AD is an open question. Thus, the aim of the current study was to assess whether higher sTREM2 attenuates the effects of ApoE4-effects on future cognitive decline and neurodegeneration. METHODS: We included 708 subjects ranging from cognitively normal (CN, n = 221) to mild cognitive impairment (MCI, n = 414) and AD dementia (n = 73) from the Alzheimer's disease Neuroimaging Initiative. We used linear regression to test the interaction between ApoE4-carriage by CSF-assessed sTREM2 levels as a predictor of longitudinally assessed cognitive decline and MRI-assessed changes in hippocampal volume changes (mean follow-up of 4 years, range of 1.7-7 years). RESULTS: Across the entire sample, we found that higher CSF sTREM2 at baseline was associated with attenuated effects of ApoE4-carriage (i.e. sTREM2 x ApoE4 interaction) on longitudinal global cognitive (p = 0.001, Cohen's f2 = 0.137) and memory decline (p = 0.006, Cohen's f2 = 0.104) as well as longitudinally assessed hippocampal atrophy (p = 0.046, Cohen's f2 = 0.089), independent of CSF markers of primary AD pathology (i.e. Aβ1-42, p-tau181). While overall effects of sTREM2 were small, exploratory subanalyses stratified by diagnostic groups showed that beneficial effects of sTREM2 were pronounced in the MCI group. CONCLUSION: Our results suggest that a higher CSF sTREM2 levels are associated with attenuated ApoE4-related risk for future cognitive decline and AD-typical neurodegeneration. These findings provide further evidence that TREM2 may be protective against the development of AD
Prion protein interacts with bace1 and differentially regulates its activity towards wild type and swedish mutant amyloid precursor protein
In Alzheimer disease amyloid-β (Aβ) peptides derived from the amyloid precursor protein (APP) accumulate in the brain. Cleavage of APP by the β-secretase BACE1 is the rate-limiting step in the production of Aβ. We have reported previously that the cellular prion protein (PrP(C)) inhibited the action of BACE1 toward human wild type APP (APP(WT)) in cellular models and that the levels of endogenous murine Aβ were significantly increased in PrP(C)-null mouse brain. Here we investigated the molecular and cellular mechanisms underlying this observation. PrP(C) interacted directly with the prodomain of the immature Golgi-localized form of BACE1. This interaction decreased BACE1 at the cell surface and in endosomes where it preferentially cleaves APP(WT) but increased it in the Golgi where it preferentially cleaves APP with the Swedish mutation (APP(Swe)). In transgenic mice expressing human APP with the Swedish and Indiana familial mutations (APP(Swe,Ind)), PrP(C) deletion had no influence on APP proteolytic processing, Aβ plaque deposition, or levels of soluble Aβ or Aβ oligomers. In cells, although PrP(C) inhibited the action of BACE1 on APP(WT), it did not inhibit BACE1 activity toward APP(Swe). The differential subcellular location of the BACE1 cleavage of APP(Swe) relative to APP(WT) provides an explanation for the failure of PrP(C) deletion to affect Aβ accumulation in APP(Swe,Ind) mice. Thus, although PrP(C) exerts no control on cleavage of APP(Swe) by BACE1, it has a profound influence on the cleavage of APP(WT), suggesting that PrP(C) may be a key protective player against sporadic Alzheimer disease
Neuroendocrine Response to Exogenous Ghrelin Administration, Combined With Alcohol, in Heavy-Drinking Individuals: Findings From a Randomized, Double-Blind, Placebo-Controlled Human Laboratory Study
Background: Accumulating evidence has established a role for the orexigenic hormone ghrelin in alcohol-seeking behaviors. Accordingly, the ghrelin system may represent a potential pharmacotherapeutic target for alcohol use disorder. Ghrelin modulates several neuroendocrine pathways, such as appetitive, metabolic, and stress-related hormones, which are particularly relevant in the context of alcohol use. The goal of the present study was to provide a comprehensive assessment of neuroendocrine response to exogenous ghrelin administration, combined with alcohol, in heavy-drinking individuals.
Methods: This was a randomized, crossover, double-blind, placebo-controlled human laboratory study, which included 2 experimental alcohol administration paradigms: i.v. alcohol self-administration and i.v. alcohol clamp. Each paradigm consisted of 2 counterbalanced sessions of i.v. ghrelin or placebo administration. Repeated blood samples were collected during each session, and peripheral concentrations of the following hormones were measured: leptin, glucagon-like peptide-1, pancreatic polypeptide, gastric inhibitory peptide, insulin, insulin-like growth factor-1, cortisol, prolactin, and aldosterone.
Results: Despite some statistical differences, findings were consistent across the 2 alcohol administration paradigms: i.v. ghrelin, compared to placebo, increased blood concentrations of glucagon-like peptide-1, pancreatic polypeptide, cortisol, and prolactin, both acutely and during the whole session. Lower levels of leptin and higher levels of aldosterone were also found during the ghrelin vs placebo session.
Conclusion: These findings, gathered from a clinically relevant sample of heavy-drinking individuals with alcohol use disorder, provide a deeper insight into the complex interplay between ghrelin and appetitive, metabolic, and stress-related neuroendocrine pathways in the context of alcohol use
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