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- Feroci, M., et al.
(författare)
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The large observatory for x-ray timing
- 2014
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Ingår i: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE. - 9780819496126
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Konferensbidrag (refereegranskat)abstract
- The Large Observatory For x-ray Timing (LOFT) was studied within ESA M3 Cosmic Vision framework and participated in the final downselection for a launch slot in 2022-2024. Thanks to the unprecedented combination of effective area and spectral resolution of its main instrument, LOFT will study the behaviour of matter under extreme conditions, such as the strong gravitational field in the innermost regions of accretion flows close to black holes and neutron stars, and the supranuclear densities in the interior of neutron stars. The science payload is based on a Large Area Detector (LAD, 10 m2 effective area, 2-30 keV, 240 eV spectral resolution, 1° collimated field of view) and a Wide Field Monitor (WFM, 2-50 keV, 4 steradian field of view, 1 arcmin source location accuracy, 300 eV spectral resolution). The WFM is equipped with an on-board system for bright events (e.g. GRB) localization. The trigger time and position of these events are broadcast to the ground within 30 s from discovery. In this paper we present the status of the mission at the end of its Phase A study.
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- Feroci, M., et al.
(författare)
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LOFT - The large observatory for x-ray timing
- 2012
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Ingår i: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE - International Society for Optical Engineering. - 9780819491442 ; , s. 84432D-
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Konferensbidrag (refereegranskat)abstract
- The LOFT mission concept is one of four candidates selected by ESA for the M3 launch opportunity as Medium Size missions of the Cosmic Vision programme. The launch window is currently planned for between 2022 and 2024. LOFT is designed to exploit the diagnostics of rapid X-ray flux and spectral variability that directly probe the motion of matter down to distances very close to black holes and neutron stars, as well as the physical state of ultradense matter. These primary science goals will be addressed by a payload composed of a Large Area Detector (LAD) and a Wide Field Monitor (WFM). The LAD is a collimated (<1 degree field of view) experiment operating in the energy range 2-50 keV, with a 10 m2 peak effective area and an energy resolution of 260 eV at 6 keV. The WFM will operate in the same energy range as the LAD, enabling simultaneous monitoring of a few-steradian wide field of view, with an angular resolution of <5 arcmin. The LAD and WFM experiments will allow us to investigate variability from submillisecond QPO's to yearlong transient outbursts. In this paper we report the current status of the project.
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- Feroci, M., et al.
(författare)
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The Large Observatory for X-ray Timing (LOFT)
- 2012
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Ingår i: Experimental Astronomy. - : Springer Science and Business Media LLC. - 0922-6435 .- 1572-9508. ; 34:2, s. 415-444
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Tidskriftsartikel (refereegranskat)abstract
- High-time-resolution X-ray observations of compact objects provide direct access to strong-field gravity, to the equation of state of ultradense matter and to black hole masses and spins. A 10 m(2)-class instrument in combination with good spectral resolution is required to exploit the relevant diagnostics and answer two of the fundamental questions of the European Space Agency (ESA) Cosmic Vision Theme "Matter under extreme conditions", namely: does matter orbiting close to the event horizon follow the predictions of general relativity? What is the equation of state of matter in neutron stars? The Large Observatory For X-ray Timing (LOFT), selected by ESA as one of the four Cosmic Vision M3 candidate missions to undergo an assessment phase, will revolutionise the study of collapsed objects in our galaxy and of the brightest supermassive black holes in active galactic nuclei. Thanks to an innovative design and the development of large-area monolithic silicon drift detectors, the Large Area Detector (LAD) on board LOFT will achieve an effective area of similar to 12 m(2) (more than an order of magnitude larger than any spaceborne predecessor) in the 2-30 keV range (up to 50 keV in expanded mode), yet still fits a conventional platform and small/medium-class launcher. With this large area and a spectral resolution of < 260 eV, LOFT will yield unprecedented information on strongly curved spacetimes and matter under extreme conditions of pressure and magnetic field strength.
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- Kotmayer, L, et al.
(författare)
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Landscape of BCL2 Resistance Mutations in a Real-World Cohort of Patients with Relapsed/Refractory Chronic Lymphocytic Leukemia Treated with Venetoclax
- 2023
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Ingår i: International journal of molecular sciences. - : MDPI AG. - 1422-0067. ; 24:6
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Tidskriftsartikel (refereegranskat)abstract
- The oral, highly selective Bcl2 inhibitor venetoclax has substantially improved the therapeutic landscape of chronic lymphocytic leukemia (CLL). Despite the remarkable response rates in patients with relapsed/refractory (R/R) disease, acquired resistance is the leading cause of treatment failure, with somatic BCL2 mutations being the predominant genetic drivers underpinning venetoclax resistance. To assess the correlation between disease progression and the most common BCL2 mutations G101V and D103Y, sensitive (10−4) screening for the most common BCL2 mutations G101V and D103Y was performed in 67 R/R CLL patients during venetoclax single-agent or venetoclax–rituximab combination therapy. With a median follow-up time of 23 months, BCL2 G101V and D103Y were detected in 10.4% (7/67) and 11.9% (8/67) of the cases, respectively, with four patients harboring both resistance mutations. Ten out of eleven patients carrying BCL2 G101V and/or D103Y experienced relapse during the follow-up period, representing 43.5% of the cases (10/23) showing clinical signs of disease progression. All BCL2 G101V or D103Y variants were detected in patients receiving venetoclax as a continuous single-agent treatment while these mutations were not observed during or after fixed-duration venetoclax therapy. Targeted ultra-deep sequencing of BCL2 uncovered three additional variants in four patient samples obtained at relapse, suggesting convergent evolution and implying a cooperating role of BCL2 mutations in driving venetoclax resistance. This cohort is the largest R/R CLL patient population reported to date in which BCL2 resistance mutations were investigated. Our study demonstrates the feasibility and clinical value of sensitive screening for BCL2 resistance mutations in R/R CLL.
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- Nagy, A, et al.
(författare)
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Quantitative Analysis and Monitoring of EZH2 Mutations Using Liquid Biopsy in Follicular Lymphoma
- 2020
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Ingår i: Genes. - : MDPI AG. - 2073-4425. ; 11:7
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Tidskriftsartikel (refereegranskat)abstract
- Recent advances in molecular technologies enable sensitive and quantitative assessment of circulating tumor DNA, offering a noninvasive disease monitoring tool for patients with malignant disorders. Here, we demonstrated on four follicular lymphoma cases that circulating tumor DNA based EZH2 mutation analysis performed by a highly sensitive droplet digital PCR method may be a valuable treatment monitoring approach in EZH2 mutant follicular lymphoma. EZH2 variant allele frequencies changed in parallel with the volume of metabolically active tumor sites observed on 18F-fluorodeoxyglucose positron emission tomography combined with computer tomography (PET-CT) scans. Variant allele frequencies of EZH2 mutations decreased or were eliminated rapidly upon successful treatment, with treatment failure being associated with elevated EZH2 variant allele frequencies. We also demonstrated spatial heterogeneity in a patient with two different EZH2 mutations in distinct anatomical sites, with both mutations simultaneously detected in the liquid biopsy specimen. In summary, circulating tumor DNA based EZH2 mutation analysis offers a rapid, real-time, radiation-free monitoring tool for sensitive detection of EZH2 mutations deriving from different anatomical sites in follicular lymphoma patients receiving immunochemotherapy.
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- Patthy, A, et al.
(författare)
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Neuropathology of the Brainstem to Mechanistically Understand and to Treat Alzheimer's Disease
- 2021
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Ingår i: Journal of clinical medicine. - : MDPI AG. - 2077-0383. ; 10:8
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Tidskriftsartikel (refereegranskat)abstract
- Alzheimer’s disease (AD) is a devastating neurodegenerative disorder as yet without effective therapy. Symptoms of this disorder typically reflect cortical malfunction with local neurohistopathology, which biased investigators to search for focal triggers and molecular mechanisms. Cortex, however, receives massive afferents from caudal brain structures, which do not only convey specific information but powerfully tune ensemble activity. Moreover, there is evidence that the start of AD is subcortical. The brainstem harbors monoamine systems, which establish a dense innervation in both allo- and neocortex. Monoaminergic synapses can co-release neuropeptides either by precisely terminating on cortical neurons or, when being “en passant”, can instigate local volume transmission. Especially due to its early damage, malfunction of the ascending monoaminergic system emerges as an early sign and possible trigger of AD. This review summarizes the involvement and cascaded impairment of brainstem monoaminergic neurons in AD and discusses cellular mechanisms that lead to their dysfunction. We highlight the significance and therapeutic challenges of transmitter co-release in ascending activating system, describe the role and changes of local connections and distant afferents of brainstem nuclei in AD, and summon the rapidly increasing diagnostic window during the last few years.
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- Gaati, G, et al.
(författare)
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Revival of calcium-binding proteins for neuromorphology: secretagogin typifies distinct cell populations in the avian brain
- 2014
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Ingår i: Brain, behavior and evolution. - : S. Karger AG. - 1421-9743 .- 0006-8977. ; 83:2, s. 82-92
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Tidskriftsartikel (refereegranskat)abstract
- In the vertebrate nervous system, the Ca<sup>2+</sup>-binding proteins parvalbumin, calbindin and calretinin have been extensively used to elaborate the molecular diversity of neuronal subtypes. Secretagogin is a phylogenetically conserved Ca<sup>2+</sup>-binding protein, which marks neuronal populations largely distinct from other Ca<sup>2+</sup>-binding proteins in mammals. Whether secretagogin is expressed in nonmammalian vertebrates, particularly in birds, and, if so, with a brain cytoarchitectonic design different from that of mammals is unknown. Here, we show that secretagogin is already present in the hatchlings' brain with continued presence into adulthood. Secretagogin-immunoreactive neurons primarily accumulate in the olfactory bulb, septum, subpallial amygdala, hippocampus, hypothalamus, habenular nuclei and deep layers of the optic tectum of adult domestic chicks <i>(Gallus domesticus)</i>. In the olfactory bulb, secretagogin labels periglomerular neurons as well as a cell continuum ascending dorsomedially, reaching the ventricular wall. Between the hippocampus and septal nuclei, the interconnecting thin septal tissue harbors secretagogin-immunoreactive neurons that contact the ventricular wall with their ramifying dendritic processes. Secretagogin is also present in the neuroendocrine hypothalamus, with particularly rich neuronal clusters seen in its suprachiasmatic and infundibular nuclei. Secretagogin expression identified a hitherto undescribed cell contingent along intratelencephalic cell-free laminae separating brain regions or marking the palliosubpallial boundary, as well as a dense neuronal population in the area corticoidea lateralis. In both the telencephalon and midbrain, secretagogin complemented the distribution of the canonical ‘neuronal' Ca<sup>2+</sup>-binding proteins. Our findings identify novel neuronal subtypes, connectivity patterns in brain areas functionally relevant to olfaction, orientation, behavior as well as endocrine functions, which will help refine existing concepts on the neuronal diversity and organizational principles of the avian brain.
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- Korchynska, S, et al.
(författare)
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A hypothalamic dopamine locus for psychostimulant-induced hyperlocomotion in mice
- 2022
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Ingår i: Nature communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 13:1, s. 5944-
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Tidskriftsartikel (refereegranskat)abstract
- The lateral septum (LS) has been implicated in the regulation of locomotion. Nevertheless, the neurons synchronizing LS activity with the brain’s clock in the suprachiasmatic nucleus (SCN) remain unknown. By interrogating the molecular, anatomical and physiological heterogeneity of dopamine neurons of the periventricular nucleus (PeVN; A14 catecholaminergic group), we find that Th+/Dat1+ cells from its anterior subdivision innervate the LS in mice. These dopamine neurons receive dense neuropeptidergic innervation from the SCN. Reciprocal viral tracing in combination with optogenetic stimulation ex vivo identified somatostatin-containing neurons in the LS as preferred synaptic targets of extrahypothalamic A14 efferents. In vivo chemogenetic manipulation of anterior A14 neurons impacted locomotion. Moreover, chemogenetic inhibition of dopamine output from the anterior PeVN normalized amphetamine-induced hyperlocomotion, particularly during sedentary periods. Cumulatively, our findings identify a hypothalamic locus for the diurnal control of locomotion and pinpoint a midbrain-independent cellular target of psychostimulants.
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- Romanov, Roman A., et al.
(författare)
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A secretagogin locus of the mammalian hypothalamus controls stress hormone release
- 2015
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Ingår i: EMBO Journal. - : EMBO. - 0261-4189 .- 1460-2075. ; 34:1, s. 36-54
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Tidskriftsartikel (refereegranskat)abstract
- A hierarchical hormonal cascade along the hypothalamic-pituitary-adrenal axis orchestrates bodily responses to stress. Although corticotropin-releasing hormone (CRH), produced by parvocellular neurons of the hypothalamic paraventricular nucleus (PVN) and released into the portal circulation at the median eminence, is known to prime downstream hormone release, the molecular mechanism regulating phasic CRH release remains poorly understood. Here, we find a cohort of parvocellular cells interspersed with magnocellular PVN neurons expressing secretagogin. Single-cell transcriptome analysis combined with protein interactome profiling identifies secretagogin neurons as a distinct CRH-releasing neuron population reliant on secretagogin's Ca2+ sensor properties and protein interactions with the vesicular traffic and exocytosis release machineries to liberate this key hypothalamic releasing hormone. Pharmacological tools combined with RNA interference demonstrate that secretagogin's loss of function occludes adrenocorticotropic hormone release from the pituitary and lowers peripheral corticosterone levels in response to acute stress. Cumulatively, these data define a novel secretagogin neuronal locus and molecular axis underpinning stress responsiveness.
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- Romanov, Roman A., et al.
(författare)
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Molecular interrogation of hypothalamic organization reveals distinct dopamine neuronal subtypes
- 2017
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Ingår i: Nature Neuroscience. - : Nature Publishing Group. - 1097-6256 .- 1546-1726. ; 20:2, s. 176-188
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Tidskriftsartikel (refereegranskat)abstract
- The hypothalamus contains the highest diversity of neurons in the brain. Many of these neurons can co-release neurotransmitters and neuropeptides in a use-dependent manner. Investigators have hitherto relied on candidate protein-based tools to correlate behavioral, endocrine and gender traits with hypothalamic neuron identity. Here we map neuronal identities in the hypothalamus by single-cell RNA sequencing. We distinguished 62 neuronal subtypes producing glutamatergic, dopaminergic or GABAergic markers for synaptic neurotransmission and harboring the ability to engage in task-dependent neurotransmitter switching. We identified dopamine neurons that uniquely coexpress the Onecut3 and Nmur2 genes, and placed these in the periventricular nucleus with many synaptic afferents arising from neuromedin S+ neurons of the suprachiasmatic nucleus. These neuroendocrine dopamine cells may contribute to the dopaminergic inhibition of prolactin secretion diurnally, as their neuromedin S+ inputs originate from neurons expressing Per2 and Per3 and their tyrosine hydroxylase phosphorylation is regulated in a circadian fashion. Overall, our catalog of neuronal subclasses provides new understanding of. hypothalamic organization and function.
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- Romanov, RA, et al.
(författare)
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Unified Classification of Molecular, Network, and Endocrine Features of Hypothalamic Neurons
- 2019
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Ingår i: Annual review of neuroscience. - : Annual Reviews. - 1545-4126 .- 0147-006X. ; 42, s. 1-26
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Tidskriftsartikel (refereegranskat)abstract
- Peripheral endocrine output relies on either direct or feed-forward multi-order command from the hypothalamus. Efficient coding of endocrine responses is made possible by the many neuronal cell types that coexist in intercalated hypothalamic nuclei and communicate through extensive synaptic connectivity. Although general anatomical and neurochemical features of hypothalamic neurons were described during the past decades, they have yet to be reconciled with recently discovered molecular classifiers and neurogenetic function determination. By interrogating magnocellular as well as parvocellular dopamine, GABA, glutamate, and phenotypically mixed neurons, we integrate available information at the molecular, cellular, network, and endocrine output levels to propose a framework for the comprehensive classification of hypothalamic neurons. Simultaneously, we single out putative neuronal subclasses for which future research can fill in existing gaps of knowledge to rationalize cellular diversity through function-determinant molecular marks in the hypothalamus.
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