377 research outputs found
Robotic Ultrasound Imaging: State-of-the-Art and Future Perspectives
Ultrasound (US) is one of the most widely used modalities for clinical
intervention and diagnosis due to the merits of providing non-invasive,
radiation-free, and real-time images. However, free-hand US examinations are
highly operator-dependent. Robotic US System (RUSS) aims at overcoming this
shortcoming by offering reproducibility, while also aiming at improving
dexterity, and intelligent anatomy and disease-aware imaging. In addition to
enhancing diagnostic outcomes, RUSS also holds the potential to provide medical
interventions for populations suffering from the shortage of experienced
sonographers. In this paper, we categorize RUSS as teleoperated or autonomous.
Regarding teleoperated RUSS, we summarize their technical developments, and
clinical evaluations, respectively. This survey then focuses on the review of
recent work on autonomous robotic US imaging. We demonstrate that machine
learning and artificial intelligence present the key techniques, which enable
intelligent patient and process-specific, motion and deformation-aware robotic
image acquisition. We also show that the research on artificial intelligence
for autonomous RUSS has directed the research community toward understanding
and modeling expert sonographers' semantic reasoning and action. Here, we call
this process, the recovery of the "language of sonography". This side result of
research on autonomous robotic US acquisitions could be considered as valuable
and essential as the progress made in the robotic US examination itself. This
article will provide both engineers and clinicians with a comprehensive
understanding of RUSS by surveying underlying techniques.Comment: Accepted by Medical Image Analysi
Crew Motion and the Dynamic Environment of Spaceborne Experiments
Analytical study of crew motion on dynamic environment of orbiting laboratorie
Post-diagnosis body mass index and mortality among women diagnosed with endometrial cancer: Results from the Women\u27s Health Initiative.
Higher body mass index (BMI) measured before endometrial cancer diagnosis has been associated with greater risk of developing endometrial cancer and higher mortality, but the association between BMI measured after diagnosis and mortality risk is unclear. We identified 467 women (91 deaths) in the Women\u27s Health Initiative (WHI) with information on BMI measured after diagnosis and used Cox proportional hazards regression to generate hazard ratios (HR) and 95% confidence intervals (CI) for all-cause mortality. Comparing BMI 35+ with/m2, we observed no association with all-cause mortality (HR = 1.02, 95% CI 0.55-1.91). Our study does not support the hypothesis that higher BMI after endometrial cancer diagnosis is associated with poorer survival
Convection enhanced delivery and \u3ci\u3ein vivo\u3c/i\u3e imaging of polymeric nanoparticles for the treatment of malignant glioma
A major obstacle to the management of malignant glioma is the inability to effectively deliver therapeutic agent to the tumor. In this study, we describe a polymeric nanoparticle vector that not only delivers viable therapeutic, but can also be tracked in vivo using MRI. Nanoparticles, produced by a non-emulsion technique, were fabricated to carry iron oxide within the shell and the chemotherapeutic agent, temozolomide (TMZ), as the payload. Nanoparticle properties were characterized and subsequently their endocytosis-mediated uptake by glioma cells demonstrated. Convection enhanced delivery (CED) can disperse nanoparticles through the rodent brain and their distribution is accurately visualized by MRI. Infusion of nanoparticles does not result in observable animal toxicity relative to control. CED of TMZ bearing nanoparticles prolongs the survival of animals with intracranial xenografts compared to control. In conclusion, the described nanoparticle vector represents a unique multifunctional platform that can be used for image-guided treatment of malignant glioma
Gametocytes: insights gained during a decade of molecular monitoring
In vertebrate hosts, malaria parasites produce specialized male and female sexual stages (gametocytes). Soon after being taken up by a mosquito, gametocytes rapidly produce gametes and, once mated, they infect their vector and can be transmitted to new hosts. Despite being the parasite stages that were first identified (over a century ago), gametocytes have remained elusive, and basic questions remain concerning their biology. However, the postgenomic era has substantiated information on the specialized molecular machinery of gametocytogenesis and expedited the development of molecular tools to detect and quantify gametocytes. The application of such highly sensitive and specific tools has opened up novel approaches and provided new insights into gametocyte biology. Here, we review the discoveries made during the past decade, highlight unanswered questions and suggest new directions
Decoy receptor DcR1 is induced in a p50/Bcl3-dependent manner and attenuates the efficacy of temozolomide
Temozolomide is used widely to treat malignant glioma but the overall response to this agent is generally poor. Resistance to DNA damaging drugs such as temozolomide has been related to the induction of anti-apoptotic proteins. Specifically, the transcription factor NF-κB has been suggested to participate in promoting the survival of cells exposed to chemotherapy. To identify factors that modulate cytotoxicity in the setting of DNA damage, we used an unbiased strategy to examine the NF-κB-dependent expression profile induced by temozolomide. By this route, we defined the decoy receptor DcR1 as a temozolomide response gene induced by a mechanism relying upon p50/NF-κB1. A conserved NF-κB binding sequence (κB-site) was identified in the proximal promoter and demonstrated to be required for DcR1 induction by temozolomide. Loss-of-function and gain-of-function studies reveal that the atypical IκB protein, Bcl3, is also required for induction of DcR1 by temozolomide. Mechanistically, DcR1 attenuates temozolomide efficacy by blunting activation of the Fas receptor pathway in p53+/+ glioma cells. Intracranial xenograft studies show that DcR1 depletion in glioma cells enhances the efficacy of temozolomide. Taken together, our results show how DcR1 upregulation mediates temozolomide resistance, and provide a rationale for DcR1 targeting as a strategy to sensitize gliomas to this widely used chemotherapy
An ancestry informative marker set for determining continental origin: validation and extension using human genome diversity panels
<p>Abstract</p> <p>Background</p> <p>Case-control genetic studies of complex human diseases can be confounded by population stratification. This issue can be addressed using panels of ancestry informative markers (AIMs) that can provide substantial population substructure information. Previously, we described a panel of 128 SNP AIMs that were designed as a tool for ascertaining the origins of subjects from Europe, Sub-Saharan Africa, Americas, and East Asia.</p> <p>Results</p> <p>In this study, genotypes from Human Genome Diversity Panel populations were used to further evaluate a 93 SNP AIM panel, a subset of the 128 AIMS set, for distinguishing continental origins. Using both model-based and relatively model-independent methods, we here confirm the ability of this AIM set to distinguish diverse population groups that were not previously evaluated. This study included multiple population groups from Oceana, South Asia, East Asia, Sub-Saharan Africa, North and South America, and Europe. In addition, the 93 AIM set provides population substructure information that can, for example, distinguish Arab and Ashkenazi from Northern European population groups and Pygmy from other Sub-Saharan African population groups.</p> <p>Conclusion</p> <p>These data provide additional support for using the 93 AIM set to efficiently identify continental subject groups for genetic studies, to identify study population outliers, and to control for admixture in association studies.</p
Decoy receptor DcR1 is induced in a p50/Bcl3-dependent manner and attenuates the efficacy of temozolomide
Temozolomide is used widely to treat malignant glioma but the overall response to this agent is generally poor. Resistance to DNA damaging drugs such as temozolomide has been related to the induction of anti-apoptotic proteins. Specifically, the transcription factor NF-κB has been suggested to participate in promoting the survival of cells exposed to chemotherapy. To identify factors that modulate cytotoxicity in the setting of DNA damage, we used an unbiased strategy to examine the NF-κB-dependent expression profile induced by temozolomide. By this route, we defined the decoy receptor DcR1 as a temozolomide response gene induced by a mechanism relying upon p50/NF-κB1. A conserved NF-κB binding sequence (κB-site) was identified in the proximal promoter and demonstrated to be required for DcR1 induction by temozolomide. Loss-of-function and gain-of-function studies reveal that the atypical IκB protein, Bcl3, is also required for induction of DcR1 by temozolomide. Mechanistically, DcR1 attenuates temozolomide efficacy by blunting activation of the Fas receptor pathway in p53+/+ glioma cells. Intracranial xenograft studies show that DcR1 depletion in glioma cells enhances the efficacy of temozolomide. Taken together, our results show how DcR1 upregulation mediates temozolomide resistance, and provide a rationale for DcR1 targeting as a strategy to sensitize gliomas to this widely used chemotherapy
ajnmmi1106003
Abstract: Molecular imaging allows direct visualization of targets and characterization of cellular pathways, as long as a high signal/background ratio can be achieved, which requires a sufficient amount of probes to accumulate in the imaging region. The Asn-Gly-Arg (NGR) tripeptide selected by phage display can specifically target tumor vasculature. Recognizing the aminopeptidase N (APN or CD13) receptor on the membrane of tumor cells, the peptide can be further internalized into cytoplasma by the endosomal pathway. Hence NGR can serve as an ideal candidate for tumor imaging, once it is conjugated with fluorescent or radiolabeled imaging probes. Herein, we highlight some recent developments of NGR peptide based imaging of tumors. Although still in the preliminary stage, some NGR probes have shown potential as promising agents in future clinical applications
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