685 research outputs found
Editorial Special Issue on Enhancement Algorithms, Methodologies and Technology for Spectral Sensing
The paper is an editorial issue on enhancement algorithms, methodologies and technology for spectral sensing and serves as a valuable and useful reference for researchers and technologists interested in the evolving state-of-the-art and/or the emerging science and technology base associated with spectral-based sensing and monitoring problem. This issue is particularly relevant to those seeking new and improved solutions for detecting chemical, biological, radiological and explosive threats on the land, sea, and in the air
A High-Throughput Screen for Wnt/β-Catenin Signaling Pathway Modulators in Human iPSC-Derived Neural Progenitors
Wnt/β-catenin signaling has emerged as a central player in pathways implicated in the pathophysiology and treatment of neuropsychiatric disorders. To identify potential novel therapeutics for these disorders, high-throughput screening (HTS) assays reporting on Wnt/β-catenin signaling in disease-relevant contexts are needed. The use of human patientâderived induced pluripotent stem cell (iPSC) models provides ideal disease-relevant context if these stem cell cultures can be adapted for HTS-compatible formats. Here, we describe a sensitive, HTS-compatible Wnt/β-catenin signaling reporter system generated in homogeneous, expandable neural progenitor cells (NPCs) derived from human iPSCs. We validated this system by demonstrating dose-responsive stimulation by several known Wnt/β-catenin signaling pathway modulators, including Wnt3a, a glycogen synthase kinase-3 (GSK3) inhibitor, and the bipolar disorder therapeutic lithium. These responses were robust and reproducible over time across many repeated assays. We then conducted a screen of ~1500 compounds from a library of Food and Drug Administrationâapproved drugs and known bioactives and confirmed the HTS hits, revealing multiple chemical and biological classes of novel small-molecule probes of Wnt/β-catenin signaling. Generating these type of pathway-selective, cell-based phenotypic assays in human iPSC-derived neural cells will advance the field of human experimental neurobiology toward the goal of identifying and validating targets for neuropsychiatric disorders.National Institute of Mental Health (U.S.) (Grant R01MH091115)Stanley Medical Research Institut
Stellar Collisions and Ultracompact X-ray Binary Formation
(abridged) We report the results of SPH calculations of parabolic collisions
between a subgiant or slightly evolved red-giant star and a neutron star (NS).
Such collisions are likely to form ultracompact X-ray binaries (UCXBs) observed
today in old globular clusters. In particular, we compute collisions of a 1.4
Msun NS with realistically modelled parent stars of initial masses 0.8 and 0.9
Msun, each at three different evolutionary stages (corresponding to three
different radii R). The distance of closest approach for the initial orbit
varies from 0.04 R (nearly head-on) to 1.3 R (grazing). These collisions lead
to the formation of a tight binary, composed of the NS and the subgiant or
red-giant core, embedded in an extremely diffuse common envelope (CE) typically
of mass ~0.1 to 0.3 Msun. Our calculations follow the binary for many hundreds
of orbits, ensuring that the orbital parameters we determine at the end of the
calculations are close to final. Some of the fluid initially in the envelope of
the (sub)giant, from 0.003 to 0.023 Msun in the cases we considered, is left
bound to the NS. The eccentricities of the resulting binaries range from about
0.2 for our most grazing collision to about 0.9 for the nearly head-on cases.
In almost all the cases we consider, gravitational radiation alone will cause
sufficiently fast orbital decay to form a UCXB within a Hubble time, and often
on a much shorter timescale. Our hydrodynamics code implements the recent SPH
equations of motion derived with a variational approach by Springel & Hernquist
and by Monaghan. Numerical noise is reduced by enforcing an analytic constraint
equation that relates the smoothing lengths and densities of SPH particles. We
present tests of these new methods to help demonstrate their improved accuracy.Comment: 41 pages, 17 figures, accepted by Ap
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Discovery of Small-Molecule Enhancers of Reactive Oxygen Species That are Nontoxic or Cause Genotype-Selective Cell Death
Elevation of reactive oxygen species (ROS) levels has been observed in many cancer cells relative to nontransformed cells, and recent reports have suggested that small-molecule enhancers of ROS may selectively kill cancer cells in various in vitro and in vivo models. We used a high-throughput screening approach to identify several hundred small-molecule enhancers of ROS in a human osteosarcoma cell line. A minority of these compounds diminished the viability of cancer cell lines, indicating that ROS elevation by small molecules is insufficient to induce death of cancer cell lines. Three chemical probes (BRD5459, BRD56491, BRD9092) are highlighted that most strongly elevate markers of oxidative stress without causing cell death and may be of use in a variety of cellular settings. For example, combining nontoxic ROS-enhancing probes with nontoxic doses of l-buthionine sulfoximine, an inhibitor of glutathione synthesis previously studied in cancer patients, led to potent cell death in more than 20 cases, suggesting that even nontoxic ROS-enhancing treatments may warrant exploration in combination strategies. Additionally, a few ROS-enhancing compounds that contain sites of electrophilicity, including piperlongumine, show selective toxicity for transformed cells over nontransformed cells in an engineered cell-line model of tumorigenesis. These studies suggest that cancer cell lines are more resilient to chemically induced increases in ROS levels than previously thought and highlight electrophilicity as a property that may be more closely associated with cancer-selective cell death than ROS elevation.Chemistry and Chemical Biolog
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Cis-Acting Regulation of Brain-Specific ANK3 Gene Expression by a Genetic Variant Associated with Bipolar Disorder
Several genome-wide association studies (GWAS) for bipolar disorder (BD) have found a strong association of the Ankyrin3 (ANK3) gene. This association spans numerous linked single nucleotide polymorphisms (SNPs) in a ~250 kb genomic region overlapping ANK3. The associated region encompasses predicted regulatory elements as well as two of six validated alternative first exons, which encode distinct protein domains at the N-terminus of the protein also known as ankyrin-G (AnkG). Using RNA Ligase-Mediated Rapid Amplification of cDNA Ends (RLM-RACE) to identify novel transcripts in conjunction with a highly sensitive, exon-specific multiplexed mRNA expression assay, we detected differential regulation of distinct ANK3 transcription start sites (TSSs) and coupling of specific 5â ends with 3â mRNA splicing events in post-mortem human brain and human stem cell-derived neural progenitors and neurons. Furthermore, allelic variation at the BDâassociated SNP rs1938526 correlated with a significant difference in cerebellar expression of a brain-specific ANK3 transcript. These findings suggest a brain-specific cis-regulatory transcriptional effect of ANK3 may be relevant to BD pathophysiology
Current management of treatment-induced bone loss in women with breast cancer treated in the United Kingdom
New therapeutic options in breast cancer have improved survival but consequently increase the relevance of late complications. Ovarian suppression/ablation and aromatase inhibitors (AI) in the adjuvant setting have improved outcome, but have clinically important adverse effects on bone health. However, investigation and management of cancer treatment-induced bone loss (CTIBL) is poorly defined with no national guidance. In 2004, a questionnaire was sent to over 500 breast surgeons and oncologists who treat breast cancer within the United Kingdom. The questionnaire evaluated access to bone densitometry and specialist expertise as well as attitudes to investigation of CTIBL and anticipated changes in the use of AI for postmenopausal early breast cancer. A total of 354 completed questionnaires were received, 47 from clinicians not currently treating breast cancer. Of the 307 evaluable questionnaires, 164 (53%) were from breast surgeons, 112 (36%) from clinical oncologists and 31 (10%) from medical oncologists. Although most respondents recognised that CTIBL was the responsibility of the treating breast team, investigations for CTIBL are limited even though most had adequate access to bone densitometry; 98 (32%) had not requested a DXA scan in the last 6 months and 224 (73%) had requested fewer than five scans. In all, 235 (76%) were not routinely investigating patients on AI for bone loss. A total of 277 (90%) felt that their practice would benefit from national guidelines to manage these patients, and the majority (59%) had little or no confidence in interpreting DXA results and advising on treatment. This questionnaire has highlighted clear deficiencies in management of CTIBL in early breast cancer. The development of national guidelines for the management of these patients and educational initiatives for breast teams are urgently required
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Scrutinizing the use of contrasted chest CTs in extremity sarcoma staging and surveillance
BackgroundSince 2015, the American College of Radiology (ACR) has recommended staging for lung metastasis via chest computed tomography (CT) without contrast for extremity sarcoma staging and surveillance. The purpose of this study was to determine our institutional compliance with this recommendation.MethodsThis was a retrospective chart review of patients diagnosed with sarcoma in the extremities who received CT imaging of the chest for pulmonary staging and surveillance at our institution from 2005 to 2023. A total of 1916 CT studies were included for analysis. We scrutinized ordering patterns before and after 2015 based on the ACR-published metastasis staging and screening guidelines. An institutional and patient cost analysis was performed between CT modalities.ResultsThe prevalence of CT scans ordered and performed with contrast was greater than those without contrast both prior and post-ACR 2015 guidelines. Furthermore, 79.2% of patient's final surveillance CTs after 2015 were performed with contrast. A cost analysis was performed and demonstrated an additional $297â704 in patient and institutional costs.ConclusionsAt our institution, upon review of CT chest imaging for pulmonary staging and surveillance in patients with extremity sarcoma the use of contrast has been routinely utilized despite a lack of evidence for its necessity and contrary to ACR guidelines
Osteoblastic lesion screening with an advanced post-processing package enabling in-plane rib reading in CT-images
Background
To evaluate screening and diagnostic accuracy for the detection of osteoblastic rib lesions using an advanced post-processing package enabling in-plane rib reading in CT-images.
Methods
We retrospectively assessed the CT-data of 60 consecutive prostate cancer patients by applying dedicated software enabling in-plane rib reading. Reading the conventional multiplanar reconstructions was considered to be the reference standard. To simulate clinical practice, the reader was given 10 s to screen for sclerotic rib lesions in each patient applying both approaches. Afterwards, every rib was evaluated individually with both approaches without a time limit. Sensitivities, specificities, positive/negative predictive values and the time needed for detection were calculated depending on the lesionâs size (largest diameterâ 10 mm).
Results
In 53 of 60 patients, all ribs were properly displayed in plane, in five patients ribs were partially displayed correctly, and in two patients none of the ribs were displayed correctly. During the 10-s screening approach all patients with sclerotic rib lesions were correctly identified reading the in-plane images (including the patients without a correct rib segmentation), whereas 14 of 23 patients were correctly identified reading conventional multiplanar images. Overall screening sensitivity, specificity, and positive/negative predictive values were 100/27.0/46.0/100 %, respectively, for in-plane reading and 60.9/100/100/80.4 %, respectively, for multiplanar reading. Overall diagnostic (no time limit) sensitivity, specificity, and positive/negative predictive values of in-plane reading were 97.8/92.8/74.6/99.5 %, respectively. False positive results predominantly occurred for lesionsâ<5 mm in size.
Conclusions
In-plane reading of the ribs allows reliable detection of osteoblastic lesions for screening purposes. The limited specificity results from false positives predominantly occurring for small lesions
Detection and Estimation Theory
Contains research objectives and summary of research.Joint Services Electronics Program (Contract DAAB07-71-C-0300)National Science Foundation (Grant GX-36331
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