Dust associated with various stellar sources in galaxies at all cosmic epochs remains a controversial topic, particularly whether supernovae play an important role in dust production. We report evidence of dust formation in the cold, dense shell behind the ejecta-circumstellar medium (CSM) interaction in the Type Ia-CSM supernova (SN) 2018evt three years after the explosion, characterized by a rise in mid-infrared emission accompanied by an accelerated decline in the optical radiation of the SN. Such a dust-formation picture is also corroborated by the concurrent evolution of the profiles of the Hα emission line.
View Article and Find Full Text PDFThe gravitationally lensed supernova Refsdal appeared in multiple images produced through gravitational lensing by a massive foreground galaxy cluster. After the supernova appeared in 2014, lens models of the galaxy cluster predicted that an additional image of the supernova would appear in 2015, which was subsequently observed. We use the time delays between the images to perform a blinded measurement of the expansion rate of the Universe, quantified by the Hubble constant ().
View Article and Find Full Text PDFBackground:: The ganglioside G is a potential circulating tumor biomarker for the childhood cancer neuroblastoma. Interpreting the levels of a circulating tumor biomarker depends in part on a knowledge of the biomarker’s clinical pharmacology.
Methods:: We studied the plasma and cerebrospinal fluid (CSF) pharmacokinetics of the C lipoform of G in two nonhuman primates with indwelling subcutaneous CSF lateral ventricular reservoir systems.
Asteroseismology probes the internal structures of stars by using their natural pulsation frequencies. It relies on identifying sequences of pulsation modes that can be compared with theoretical models, which has been done successfully for many classes of pulsators, including low-mass solar-type stars, red giants, high-mass stars and white dwarfs. However, a large group of pulsating stars of intermediate mass-the so-called δ Scuti stars-have rich pulsation spectra for which systematic mode identification has not hitherto been possible.
View Article and Find Full Text PDFPurpose: Pexidartinib (PLX3397) is a colony-stimulating factor-1 receptor (CSF-1R) inhibitor under clinical evaluation for potential CNS tumor treatment. This study aims to evaluate plasma pharmacokinetic parameters and estimate CNS penetrance of pexidartinib in a non-human primate (NHP) cerebrospinal fluid (CSF) reservoir model.
Methods: Five male rhesus macaques, each with a previously implanted subcutaneous CSF ventricular reservoir and central venous lines, were used.
Every supernova so far observed has been considered to be the terminal explosion of a star. Moreover, all supernovae with absorption lines in their spectra show those lines decreasing in velocity over time, as the ejecta expand and thin, revealing slower-moving material that was previously hidden. In addition, every supernova that exhibits the absorption lines of hydrogen has one main light-curve peak, or a plateau in luminosity, lasting approximately 100 days before declining.
View Article and Find Full Text PDFIn 1964, Refsdal hypothesized that a supernova whose light traversed multiple paths around a strong gravitational lens could be used to measure the rate of cosmic expansion. We report the discovery of such a system. In Hubble Space Telescope imaging, we have found four images of a single supernova forming an Einstein cross configuration around a redshift z = 0.
View Article and Find Full Text PDFType Iax supernovae are stellar explosions that are spectroscopically similar to some type Ia supernovae at the time of maximum light emission, except with lower ejecta velocities. They are also distinguished by lower luminosities. At late times, their spectroscopic properties diverge from those of other supernovae, but their composition (dominated by iron-group and intermediate-mass elements) suggests a physical connection to normal type Ia supernovae.
View Article and Find Full Text PDFPediatric diffuse intrinsic pontine gliomas are aggressive brainstem tumors that fail to respond to treatment. We hypothesize that the protective features of the pons may hinder chemotherapeutic agents from entering pontine tissue compared with cortical brain tissue. To test this hypothesis, we developed a unique nonhuman primate model using microdialysis, a continuous in vivo extracellular sampling technique, to compare drug exposure concurrently in pontine tissue, cortical tissue, CSF, and plasma after intravenous administration of chemotherapeutic agents.
View Article and Find Full Text PDFType Ia supernovae are thought to result from a thermonuclear explosion of an accreting white dwarf in a binary system, but little is known of the precise nature of the companion star and the physical properties of the progenitor system. There are two classes of models: double-degenerate (involving two white dwarfs in a close binary system) and single-degenerate models. In the latter, the primary white dwarf accretes material from a secondary companion until conditions are such that carbon ignites, at a mass of 1.
View Article and Find Full Text PDFBackground: Satraplatin is an orally bioavailable platinum analog with preclinical activity in cisplatin resistant models and clinical activity in adults with refractory cancers. The cerebrospinal fluid (CSF) penetration of cisplatin and carboplatin in non-human primates (NHP) is limited (3.7 and 2.
View Article and Find Full Text PDFPurpose: Sorafenib is a small molecule inhibitor of multiple signaling kinases thought to contribute to the pathogenesis of many tumors including brain tumors. Clinical trials with sorafenib in primary and metastatic brain tumors are ongoing. We evaluated the plasma and cerebrospinal fluid (CSF) pharmacokinetics (PK) of sorafenib after an intravenous (IV) dose in a non-human primate (NHP) model.
View Article and Find Full Text PDFPurpose: O(6)-alkylguanine-DNA alkyltransferase (AGT) repairs DNA damage from alkylating agents by transferring the alkyl adducts from the O(6)-position of guanine in DNA to AGT. The folate analog O(4)-benzylfolic acid (O(4)BF) is an inhibitor of AGT with reported selectivity of the alpha-folate receptor in tumors. We studied plasma and cerebrospinal fluid (CSF) pharmacokinetics and CSF penetration of O(4)BF in a non-human primate model.
View Article and Find Full Text PDFAnakinra improves the central nervous system manifestations of neonatal-onset multisystem inflammatory disease, which is mediated by IL-1beta oversecretion. The cerebrospinal fluid (CSF) penetration of the IL-1 receptor antagonist anakinra was studied in rhesus monkeys after intravenous doses of 3 and 10 mg/kg. Drug exposure (area under concentration-time curve) in CSF was 0.
View Article and Find Full Text PDFPurpose: Cisplatin, carboplatin, and oxaliplatin are chemically reactive anticancer drugs with modest activity in brain tumors. Previously, we have demonstrated that drug exposure in cerebrospinal fluid (CSF) for these platinum analogs is <5% of the plasma ultrafiltrate (UF) drug exposure in nonhuman primates. Microdialysis is a minimally invasive in vivo method for sampling small molecules in the blood and tissue extracellular fluid (ECF).
View Article and Find Full Text PDFPurpose: Histone deacetylases (HDAC) are involved in the regulation of gene transcription. Aberrant HDAC activity has been associated with tumorigenesis, and, therefore, HDACs are potential targets for the treatment of cancers, including tumors of the central nervous system (CNS). Belinostat is a novel, potent, pan-HDAC inhibitor with antiproliferative activity on a wide variety of tumor cell lines.
View Article and Find Full Text PDFPurpose: Erlotinib hydrochloride is a small molecule inhibitor of epidermal growth factor receptor (EGFR). EGFR is over-expressed in primary brain tumors and solid tumors that metastasize to the central nervous system. We evaluated the plasma and cerebrospinal fluid (CSF) pharmacokinetics of erlotinib and its active metabolite OSI-420 after an intravenous (IV) dose in a non-human primate model.
View Article and Find Full Text PDFObtaining resources for quality patient care is a major responsibility of nurse leaders and requires accurate information in the political world of budgeting. Patient classification systems (PCS) assist nurse managers in controlling cost and improving patient care while appropriately using financial resources. This paper communicates acuity systems development, background, flaws, and components while discussing a few tools currently available.
View Article and Find Full Text PDFCancer Chemother Pharmacol
September 2007
Purpose: ABT-751 is an orally bioavailable sulfonamide that binds to the colchicine binding site on beta-tubulin and inhibits microtubule polymerization. The plasma and cerebrospinal fluid (CSF) pharmacokinetics of ABT-751, after a short intravenous infusion, were evaluated in a non-human primate (Macaca mulatta) model that is highly predictive of the CSF penetration of drugs in humans.
Materials And Methods: Plasma and CSF samples were collected over 24 h after 7.
Purpose: Describe and compare the central nervous system pharmacology of the platinum analogues, cisplatin, carboplatin, and oxaliplatin and develop a pharmacokinetic model to distinguish the disposition of active drug from inert platinum species.
Experimental Design: Oxaliplatin (7 or 5 mg/kg), cisplatin (2 mg/kg), or carboplatin (10 mg/kg) was given i.v.
Purpose: Preclinical studies of mafosfamide, a preactivated cyclophosphamide analog, were performed to define a tolerable and potentially active target concentration for intrathecal (IT) administration. A phase I and pharmacokinetic study of IT mafosfamide was performed to determine a dose for subsequent phase II trials.
Patients And Methods: In vitro cytotoxicity studies were performed in MCF-7, Molt-4, and rhabdomyosarcoma cell lines.
Purpose: Imatinib mesylate (Gleevec, Glivec, STI571, imatinib) is a potent tyrosine kinase inhibitor approved for the treatment of chronic myelogenous leukemia and gastrointestinal stromal tumors. The role of imatinib in the treatment of malignant gliomas and other solid tumors is being evaluated. We used a nonhuman primate model that is highly predictive of the cerebrospinal fluid penetration of drugs in humans to study the pharmacokinetics of imatinib in plasma and cerebrospinal fluid (CSF) after i.
View Article and Find Full Text PDFTemozolomide is a prodrug that undergoes spontaneous chemical degradation at physiologic pH to form the highly reactive alkylating agent, methyl-triazenyl imidazole carboxamide (MTIC). In clinical trials, temozolomide has activity in gliomas and is approved for recurrent anaplastic astrocytoma. We, therefore, studied the penetration of temozolomide into the cerebrospinal fluid (CSF) as a surrogate for blood-brain barrier penetration in a non-human primate model.
View Article and Find Full Text PDFNonhuman primates might experience stress during periods of restraint associated with research procedures. In an attempt to minimize such stress, the authors describe an enrichment program they designed for use with restrained adult male rhesus macaques.
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