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Find video protocols related to scientific articles indexed in Pubmed.
Are Elderly Patients With Clinically Localized Prostate Cancer Overtreated? Exploring Heterogeneity in Survival Effects.
Med Care
PUBLISHED: 11-15-2014
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Clinical trial evidence shows minimal survival gains and higher complication rates from radical prostatectomy (RP) versus watchful waiting (WW) for elderly men with localized prostate cancer (PCa). It is believed that these patients are overtreated. The current analyses aim to explore patient-level heterogeneity in survival effects, examine matching of patients to treatments in practice, and identify patient characteristics driving heterogenous effects, in order to present more comprehensive evidence about the concerns of overtreatment.
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Proximal nerve magnetization transfer MRI relates to disability in Charcot-Marie-Tooth diseases.
Neurology
PUBLISHED: 09-24-2014
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The objectives of this study were (1) to develop a novel magnetization transfer ratio (MTR) MRI assay of the proximal sciatic nerve (SN), which is inaccessible via current tools for assessing peripheral nerves, and (2) to evaluate the resulting MTR values as a potential biomarker of myelin content changes in patients with Charcot-Marie-Tooth (CMT) diseases.
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Inhalable Curcumin: Offering the Potential for Translation to Imaging and Treatment of Alzheimer's Disease.
J. Alzheimers Dis.
PUBLISHED: 09-18-2014
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Curcumin is a promising compound that can be used as a theranostic agent to aid research in Alzheimer's disease. Beyond its ability to bind to amyloid plaques, the compound can also cross the blood-brain barrier. Presently, curcumin can be applied only to animal models, as the formulation needed for iv injection renders it unfit for human use. Here, we describe a novel technique to aerosolize a curcumin derivative, FMeC1, and facilitate its safe delivery to the brain. Aside from the translational applicability of this approach, a study in the 5XFAD mouse model suggested that inhalation exposure to an aerosolized FMeC1 modestly improved the distribution of the compound in the brain. Additionally, immunohistochemistry data confirms that following aerosol delivery, FMeC1 binds amyloid plaques expressed in the hippocampal areas and cortex.
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Consensus statement with recommendations on active surveillance inclusion criteria and definition of progression in men with localized prostate cancer: the critical role of the pathologist.
Virchows Arch.
PUBLISHED: 09-01-2014
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Active surveillance (AS) is an important management option for men with low-risk, clinically localized prostate cancer. The clinical parameters for patient selection and definition of progression for AS protocols are evolving as data from several large cohorts matures. Vital to this process is the critical role pathologic parameters play in identifying appropriate candidates for AS. These findings need to be reproducible and consistently reported by surgical pathologists. This report highlights the importance of accurate pathology reporting as a critical component of these protocols.
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Robust expertise effects in right FFA.
Neuropsychologia
PUBLISHED: 09-01-2014
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The fusiform face area (FFA) is one of several areas in occipito-temporal cortex whose activity is correlated with perceptual expertise for objects. Here, we investigate the robustness of expertise effects in FFA and other areas to a strong task manipulation that increases both perceptual and attentional demands. With high-resolution fMRI at 7T, we measured responses to images of cars, faces and a category globally visually similar to cars (sofas) in 26 subjects who varied in expertise with cars, in (a) a low load 1-back task with a single object category and (b) a high load task in which objects from two categories were rapidly alternated and attention was required to both categories. The low load condition revealed several areas more active as a function of expertise, including both posterior and anterior portions of FFA bilaterally (FFA1/FFA2, respectively). Under high load, fewer areas were positively correlated with expertise and several areas were even negatively correlated, but the expertise effect in face-selective voxels in the anterior portion of FFA (FFA2) remained robust. Finally, we found that behavioral car expertise also predicted increased responses to sofa images but no behavioral advantages in sofa discrimination, suggesting that global shape similarity to a category of expertise is enough to elicit a response in FFA and other areas sensitive to experience, even when the category itself is not of special interest. The robustness of expertise effects in right FFA2 and the expertise effects driven by visual similarity both argue against attention being the sole determinant of expertise effects in extrastriate areas.
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Overuse of Antimicrobial Prophylaxis in Community Practice Urology.
J. Urol.
PUBLISHED: 08-27-2014
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We examined index urologic surgeries to assess utilization patterns for antimicrobial prophylaxis in a large community-based population.
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Detection of a novel mechanism of acousto-optic modulation of incoherent light.
PLoS ONE
PUBLISHED: 08-08-2014
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A novel form of acoustic modulation of light from an incoherent source has been detected in water as well as in turbid media. We demonstrate that patterns of modulated light intensity appear to propagate as the optical shadow of the density variations caused by ultrasound within an illuminated ultrasonic focal zone. This pattern differs from previous reports of acousto-optical interactions that produce diffraction effects that rely on phase shifts and changes in light directions caused by the acoustic modulation. Moreover, previous studies of acousto-optic interactions have mainly reported the effects of sound on coherent light sources via photon tagging, and/or the production of diffraction phenomena from phase effects that give rise to discrete sidebands. We aimed to assess whether the effects of ultrasound modulation of the intensity of light from an incoherent light source could be detected directly, and how the acoustically modulated (AOM) light signal depended on experimental parameters. Our observations suggest that ultrasound at moderate intensities can induce sufficiently large density variations within a uniform medium to cause measurable modulation of the intensity of an incoherent light source by absorption. Light passing through a region of high intensity ultrasound then produces a pattern that is the projection of the density variations within the region of their interaction. The patterns exhibit distinct maxima and minima that are observed at locations much different from those predicted by Raman-Nath, Bragg, or other diffraction theory. The observed patterns scaled appropriately with the geometrical magnification and sound wavelength. We conclude that these observed patterns are simple projections of the ultrasound induced density changes which cause spatial and temporal variations of the optical absorption within the illuminated sound field. These effects potentially provide a novel method for visualizing sound fields and may assist the interpretation of other hybrid imaging methods.
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Resting state functional connectivity in the human spinal cord.
Elife
PUBLISHED: 08-07-2014
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Functional magnetic resonance imaging using blood oxygenation level dependent (BOLD) contrast is well established as one of the most powerful methods for mapping human brain function. Numerous studies have measured how low-frequency BOLD signal fluctuations from the brain are correlated between voxels in a resting state, and have exploited these signals to infer functional connectivity within specific neural circuits. However, to date there have been no previous substantiated reports of resting state correlations in the spinal cord. In a cohort of healthy volunteers, we observed robust functional connectivity between left and right ventral (motor) horns, and between left and right dorsal (sensory) horns. Our results demonstrate that low-frequency BOLD fluctuations are inherent in the spinal cord as well as the brain, and by analogy to cortical circuits, we hypothesize that these correlations may offer insight into the execution and maintenance of sensory and motor functions both locally and within the cerebrum.DOI: http://dx.doi.org/10.7554/eLife.02812.001.
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The critical role of the pathologist in determining eligibility for active surveillance as a management option in patients with prostate cancer: consensus statement with recommendations supported by the College of American Pathologists, International Society of Urologic
Arch. Pathol. Lab. Med.
PUBLISHED: 08-05-2014
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Prostate cancer remains a significant public health problem. Recent publications of randomized trials and the US Preventive Services Task Force recommendations have drawn attention to overtreatment of localized, low-risk prostate cancer. Active surveillance, in which patients undergo regular visits with serum prostate-specific antigen tests and repeat prostate biopsies, rather than aggressive treatment with curative intent, may address overtreatment of low-risk prostate cancer. It is apparent that a greater awareness of the critical role of pathologists in determining eligibility for active surveillance is needed.
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Surgical pathology and the patient: a systematic review evaluating the primary audience of pathology reports.
Hum. Pathol.
PUBLISHED: 07-25-2014
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The pathology report is a critical document that helps guide the management of patients with cancer. More and more patients read their reports, intending to participate in decisions about their care. However, a substantial subset of patients may lack the ability to comprehend this often technical and complex document. We hypothesized that most literature on pathology reports discusses reports from the perspective of other physicians and not from the perspective of patients. An expert panel of physicians developed a list of search criteria, which we used to identify articles on PubMed, MEDLINE, Cochrane Reviews, and Google Scholar databases. Two reviewers independently evaluated all articles to identify for detailed review those that met search criteria. We identified the primary audience of the selected articles and the degree to which these articles addressed clarity of communication of pathology reports with patients. Of 801 articles identified in our search, 25 involved the formatting of pathology reports for clarity of communication. Recurrent themes in proposed improvements in reports included content standardization, variation in terminology, clarity of communication, and quality improvement. No articles discussed patients as their target audience. No study evaluated the health literacy level required of patients to comprehend pathology reports. In summary, there is a scarcity of patient-centered approaches to improve pathology reports. The literature on pathology reports does not include patients as a target audience. Limited resources are available to help patients comprehend their reports. Efforts to improve patient-centered communication are desirable to address this overlooked aspect of patient care.
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High Regional Variation in Urethroplasty Utilization in the United States.
J. Urol.
PUBLISHED: 07-15-2014
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We identified clinical and regional factors associated with the use of urethroplasty vs repeat endoscopic management for urethral stricture disease.
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Chemical exchange in knee cartilage assessed by R1? (1/T1?) dispersion at 3T.
Magn Reson Imaging
PUBLISHED: 07-01-2014
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To quantify the characteristics of proton chemical exchange in knee cartilage in vivo by R1? dispersion analysis.
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The burden of bladder cancer care: direct and indirect costs.
Curr Opin Urol
PUBLISHED: 06-03-2014
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Bladder cancer is a common, complex, and costly disease. Every year in the USA, bladder cancer is responsible for 70?,000 diagnosed cases and over 15,?000 deaths. Once diagnosed, patients with nonmuscle invasive bladder cancer (NMIBC) are committed to a lifetime of invasive procedures and potential hospitalizations that result in substantial direct and indirect costs.
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Fluorescence-based endoscopic imaging of Thomsen-Friedenreich antigen to improve early detection of colorectal cancer.
Int. J. Cancer
PUBLISHED: 05-20-2014
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Thomsen-Friedenreich (TF) antigen belongs to the mucin-type tumor-associated carbohydrate antigen. Notably, TF antigen is overexpressed in colorectal cancer (CRC) but is rarely expressed in normal colonic tissue. Increased TF antigen expression is associated with tumor invasion and metastasis. In this study, we sought to validate a novel nanobeacon for imaging TF-associated CRC in a preclinical animal model. We developed and characterized the nanobeacon for use with fluorescence colonoscopy. In vivo imaging was performed on an orthotopic rat model of CRC. Both white light and fluorescence colonoscopy methods were utilized to establish the ratio-imaging index for the probe. The nanobeacon exhibited specificity for TF-associated cancer. Fluorescence colonoscopy using the probe can detect lesions at the stage which is not readily confirmed by conventional visualization methods. Further, the probe can report the dynamic change of TF expression as tumor regresses during chemotherapy. Data from this study suggests that fluorescence colonoscopy can improve early CRC detection. Supplemented by the established ratio-imaging index, the probe can be used not only for early detection, but also for reporting tumor response during chemotherapy. Furthermore, since the data obtained through in vivo imaging confirmed that the probe was not absorbed by the colonic mucosa, no registered toxicity is associated with this nanobeacon. Taken together, these data demonstrate the potential of this novel probe for imaging TF antigen as a biomarker for the early detection and prediction of the progression of CRC at the molecular level.
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Knowledge of the harms of tobacco use among patients with bladder cancer.
Cancer
PUBLISHED: 05-17-2014
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The objective of this study was to determine tobacco use knowledge and attribution of cause in patients with newly diagnosed bladder cancer.
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An Approach to Breast Cancer Diagnosis via PET Imaging of Microcalcifications Using 18F-NaF.
J. Nucl. Med.
PUBLISHED: 05-15-2014
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Current radiologic methods for diagnosing breast cancer detect specific morphologic features of solid tumors or any associated calcium deposits. These deposits originate from an early molecular microcalcification process of 2 types: type 1 is calcium oxylate and type II is carbonated calcium hydroxyapatite. Type I microcalcifications are associated mainly with benign tumors, whereas type II microcalcifications are produced internally by malignant cells. No current noninvasive in vivo techniques are available for detecting intratumoral microcalcifications. Such a technique would have a significant impact on breast cancer diagnosis and prognosis in preclinical and clinical settings. (18)F-NaF PET has been used solely for bone imaging by targeting the bone hydroxyapatite. In this work, we provide preliminary evidence that (18)F-NaF PET imaging can be used to detect breast cancer by targeting the hydroxyapatite lattice within the tumor microenvironment with high specificity and soft-tissue contrast-to-background ratio while delineating tumors from inflammation.
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Measurement of regional cerebral glucose uptake by magnetic resonance spin-lock imaging.
Magn Reson Imaging
PUBLISHED: 05-09-2014
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The regional uptake of glucose in rat brain in vivo was measured at high resolution using spin-lock magnetic resonance imaging after infusion of the glucose analogue 2-deoxy-d-glucose (2DG). Previous studies of glucose metabolism have used 13C-labeled 2DG and NMR spectroscopy, 18F-labeled fluorodeoxyglucose (FDG) and PET, or chemical exchange saturation transfer (CEST) MRI, all of which have practical limitations. Our goal was to explore the ability of spin-lock sequences to detect specific chemically-exchanging species in vivo and to compare the effects of 2DG in brain tissue on CEST images.
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User-centered design of quality of life reports for clinical care of patients with prostate cancer.
Surgery
PUBLISHED: 05-03-2014
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Primary treatment of localized prostate cancer can result in bothersome urinary, sexual, and bowel symptoms. Yet clinical application of health-related quality-of-life (HRQOL) questionnaires is rare. We employed user-centered design to develop graphic dashboards of questionnaire responses from patients with prostate cancer to facilitate clinical integration of HRQOL measurement.
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Multiparametric MRI reveals dynamic changes in molecular signatures of injured spinal cord in monkeys.
Magn Reson Med
PUBLISHED: 04-07-2014
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To monitor the spontaneous recovery of cervical spinal cord injury (SCI) using longitudinal multiparametric MRI methods.
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Multifunctional yolk-in-shell nanoparticles for pH-triggered drug release and imaging.
Small
PUBLISHED: 03-23-2014
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Multifunctional nanoparticles are synthesized for both pH-triggered drug release and imaging with radioluminescence, upconversion luminescent, and magnetic resonance imaging (MRI). The particles have a yolk-in-shell morphology, with a radioluminescent core, an upconverting shell, and a hollow region between the core and shell for loading drugs. They are synthesized by controlled encapsulation of a radioluminescent nanophosphor yolk in a silica shell, partial etching of the yolk in acid, and encapsulation of the silica with an upconverting luminescent shell. Metroxantrone, a chemotherapy drug, was loaded into the hollow space between X-ray phosphor yolk and up-conversion phosphor shell through pores in the shell. To encapsulate the drug and control the release rate, the nanoparticles are coated with pH-responsive biocompatible polyelectrolyte layers of charged hyaluronic acid sodium salt and chitosan. The nanophosphors display bright luminescence under X-ray, blue light (480 nm), and near infrared light (980 nm). They also served as T1 and T2 MRI contrast agents with relaxivities of 3.5 mM(-1) s(-1) (r1 ) and 64 mM(-1) s(-1) (r2 ). These multifunctional nanocapsules have applications in controlled drug delivery and multimodal imaging.
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Readability of urologic pathology reports: The need for patient-centered approaches.
Urol. Oncol.
PUBLISHED: 03-18-2014
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The pathology report informs a patient?s prognosis and treatment options. However, pathology reports are written using complex medical vocabulary. We evaluated the readability of pathology reports for common urologic cancers (prostate, bladder kidney, and testicular) to identify sources of confusion that could be addressed through modified patient-centered pathology reports.
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Improved diffusion tensor imaging of the optic nerve using multishot two-dimensional navigated acquisitions.
Magn Reson Med
PUBLISHED: 03-17-2014
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A diffusion-weighted multishot echo-planar imaging approach combined with SENSE and a two-dimensional (2D) navigated motion correction was investigated as an alternative to conventional single-shot counterpart to obtain optic nerve images at higher spatial resolution with reduced artifacts.
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Specificity of lectin-immobilized fluorescent nanospheres for colorectal tumors in a mouse model which better resembles the clinical disease.
Contrast Media Mol Imaging
PUBLISHED: 03-17-2014
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We have been investigating an imaging agent that enables real-time and accurate diagnosis of early colorectal cancer at the intestinal mucosa by colonoscopy. The imaging agent is peanut agglutinin-immobilized polystyrene nanospheres with surface poly(N-vinylacetamide) chains encapsulating coumarin 6. Intracolonically-administered lectin-immobilized fluorescent nanospheres detect tumor-derived changes through molecular recognition of lectin for the terminal sugar of cancer-specific antigens on the mucosal surface. The focus of the present study was to evaluate imaging abilities of the nanospheres in animal models that reflect clinical environments. We previously developed an orthotopic mouse model with human colorectal tumors growing on the mucosa of the descending colon to better resemble the clinical disease. The entire colon of the mice in the exposed abdomen was monitored in real time with an in vivo imaging apparatus. Fluorescence from the nanospheres was observed along the entire descending colon after intracolonical administration from the anus. When the luminal side of the colon was washed with phosphate-buffered saline, most of the nanospheres were flushed. However, fluorescence persisted in areas where cancer cells were implanted. Histological evaluation demonstrated that tumors were present in the mucosal epithelia where the nanospheres fluoresced. In contrast, no fluorescence was observed when control mice, without tumors were tested. The lectin-immobilized fluorescent nanospheres were tumor-specific and remained bound to tumors even after vigorous washing. The nanospheres nonspecifically bound to normal mucosa were easily removed through mild washing. These results indicate that the nanospheres combined with colonoscopy, will be a clinically-valuable diagnostic tool for early-stage primary colon carcinoma. Copyright © 2014 John Wiley & Sons, Ltd.
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Mapping mean axon diameter and axonal volume fraction by MRI using temporal diffusion spectroscopy.
Neuroimage
PUBLISHED: 03-12-2014
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Mapping mean axon diameter and intra-axonal volume fraction may have significant clinical potential because nerve conduction velocity is directly dependent on axon diameter, and several neurodegenerative diseases affect axons of specific sizes and alter axon counts. Diffusion-weighted MRI methods based on the pulsed gradient spin echo (PGSE) sequence have been reported to be able to assess axon diameter and volume fraction non-invasively. However, due to the relatively long diffusion times used, e.g. >20ms, the sensitivity to small axons (diameter<2?m) is low, and the derived mean axon diameter has been reported to be overestimated. In the current study, oscillating gradient spin echo (OGSE) diffusion sequences with variable frequency gradients were used to assess rat spinal white matter tracts with relatively short effective diffusion times (1-5ms). In contrast to previous PGSE-based methods, the extra-axonal diffusion cannot be modeled as hindered (Gaussian) diffusion when short diffusion times are used. Appropriate frequency-dependent rates are therefore incorporated into our analysis and validated by histology-based computer simulation of water diffusion. OGSE data were analyzed to derive mean axon diameters and intra-axonal volume fractions of rat spinal white matter tracts (mean axon diameter of ~1.27-5.54?m). The estimated values were in good agreement with histology, including the small axon diameters (<2.5?m). This study establishes a framework for the quantification of nerve morphology using the OGSE method with high sensitivity to small axons.
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Functional MRI using spin lock editing preparation pulses.
Magn Reson Imaging
PUBLISHED: 03-11-2014
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A novel approach for detecting blood oxygenation level-dependent (BOLD) signals in the brain is investigated using spin locking (SL) pulses to selectively edit the effects of extravascular diffusion in field gradients from different sized vascular structures. We show that BOLD effects from diffusion amongst susceptibility gradients will contribute significantly not only to transverse relaxation rates (R2* and R2) but also to R1?, the rate of longitudinal relaxation in the rotating frame. Similar to the ability of 180-degree pulses to refocus static dephasing effects in a spin echo, moderately strong SL pulses can also reduce contributions of diffusion in large-scale gradients and the choice of SL amplitude can be used to selectively emphasize smaller scale inhomogeneities (such as microvasculature) and to drastically reduce the influence of larger structures (such as veins). Moreover, measurements over a range of locking fields can be used to derive estimates of the spatial scales of intrinsic gradients. The method was used to detect BOLD activation in human visual cortex. Eight healthy young adults were imaged at 3T using a single-slice, SL-prepped turbo spin echo (TSE) sequence with spin-lock amplitudes ?1=80Hz and 400Hz, along with conventional T2*-weighted and T2-prepped sequences. The BOLD signal varied from 1.1±0.4 % (?1=80Hz) to 0.7±0.2 % (at 400Hz), whereas the T2-weighted sequence measured 1.3±0.3 % and the T2* sequence measured 1.9±0.3 %. This new R1? functional contrast can be made selectively sensitive to intrinsic gradients of different spatial scales, thereby increasing the spatial specificity of the evoked response.
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Expected population impacts of discontinued prostate-specific antigen screening.
Cancer
PUBLISHED: 03-07-2014
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Prostate-specific antigen (PSA) screening for prostate cancer has high risks of overdiagnosis, particularly among older men, and reports from screening trials indicate that it saves few lives after 11 to 13 years of follow-up. New clinical guidelines recommend against PSA screening for all men or for men aged >70 years, but, to the authors' knowledge, the expected population effects of these guidelines have not been studied to date.
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Iron-Loaded Magnetic Nanocapsules for pH-Triggered Drug Release and MRI Imaging.
Chem Mater
PUBLISHED: 02-24-2014
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Magnetic nanocapsules were synthesized for controlled drug release, magnetically assisted delivery, and MRI imaging. These magnetic nanocapsules, consisting of a stable iron nanocore and a mesoporous silica shell, were synthesized by controlled encapsulation of ellipsoidal hematite in silica, partial etching of the hematite core in acid, and reduction of the core by hydrogen. The iron core provided a high saturation magnetization and was stable against oxidation for at least 6 months in air and 1 month in aqueous solution. The hollow space between the iron core and mesoporous silica shell was used to load anticancer drug and a T1-weighted MRI contrast agent (Gd-DTPA). These multifunctional monodispersed magnetic "nanoeyes" were coated by multiple polyelectrolyte layers of biocompatible poly-l-lysine and sodium alginate to control the drug release as a function of pH. We studied pH-controlled release, magnetic hysteresis curves, and T1/T2 MRI contrast of the magnetic nanoeyes. They also served as MRI contrast agents with relaxivities of 8.6 mM(-1) s(-1) (r 1) and 285 mM(-1) s(-1) (r 2).
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Use and outcomes of extended antibiotic prophylaxis in urological cancer surgery.
J. Urol.
PUBLISHED: 02-24-2014
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Although perioperative antibiotic prophylaxis prevents postoperative infectious complications, national guidelines recommend cessation of antibiotics within 24 hours after the procedure. Extended antibiotic prophylaxis beyond 24 hours may contribute to hospital acquired infections such as Clostridium difficile colitis. We evaluated practice patterns of antibiotic prophylaxis in genitourinary cancer surgery and assessed the impact of antibiotic prophylaxis on hospital acquired C. difficile infections.
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Multiplicative intrinsic component optimization (MICO) for MRI bias field estimation and tissue segmentation.
Magn Reson Imaging
PUBLISHED: 02-21-2014
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This paper proposes a new energy minimization method called multiplicative intrinsic component optimization (MICO) for joint bias field estimation and segmentation of magnetic resonance (MR) images. The proposed method takes full advantage of the decomposition of MR images into two multiplicative components, namely, the true image that characterizes a physical property of the tissues and the bias field that accounts for the intensity inhomogeneity, and their respective spatial properties. Bias field estimation and tissue segmentation are simultaneously achieved by an energy minimization process aimed to optimize the estimates of the two multiplicative components of an MR image. The bias field is iteratively optimized by using efficient matrix computations, which are verified to be numerically stable by matrix analysis. More importantly, the energy in our formulation is convex in each of its variables, which leads to the robustness of the proposed energy minimization algorithm. The MICO formulation can be naturally extended to 3D/4D tissue segmentation with spatial/sptatiotemporal regularization. Quantitative evaluations and comparisons with some popular softwares have demonstrated superior performance of MICO in terms of robustness and accuracy.
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Burden and timing of venothrombolic events in patients younger than 65 years undergoing radical cystectomy for bladder cancer.
Urol. Oncol.
PUBLISHED: 02-15-2014
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Venothrombolic events (VTEs) following radical cystectomy (RC) are a significant contributor to postoperative morbidity. A better understanding of the incidence and timing of VTE would clarify chemoprophylaxis strategies among RC patients. We sought to characterize the burden of VTE after RC by defining their timing and effect utilizing the MarketScan commercial databases.
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Distinct fine-scale fMRI activation patterns of contra- and ipsilateral somatosensory areas 3b and 1 in humans.
Hum Brain Mapp
PUBLISHED: 02-12-2014
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Inter-areal and ipsilateral cortical responses to tactile stimulation have not been well described in human S1 cortex. By taking advantage of the high signal-to-noise ratio at 7 T, we quantified blood oxygenation level dependent (BOLD) response patterns and time courses to tactile stimuli on individual distal finger pads at a fine spatial scale, and examined whether there are inter-areal (area 3b versus area 1) and interhemispheric response differences to unilateral tactile stimulation in healthy human subjects. We found that 2-Hz tactile stimulation of individual fingertips evoked detectable BOLD signal changes in both contralateral and ipsilateral area 3b and area 1. Contralateral digit activations were organized in an orderly somatotopic manner, and BOLD responses in area 3b were more digit selective than those in area 1. However, the area of cortex that was responsive to stimulation of a single digit (stimulus-response field) was similar across areas. In the ipsilateral hemisphere, response magnitudes in both areas 3b and 1 were significantly weaker than those of the contralateral hemisphere. Digit activations exhibited no clear somatotopic organizational pattern in either area 3b or area 1, yet digit selectivity was retained in area 1 but not in area 3b. The observation of distinct digit-selective responses of contralateral area 3b versus area 1 supports a higher order function of contralateral area 1 in spatial integration. In contrast, ipsilateral cortices may play a less discriminative role in the perception of unilateral tactile sensation in humans.
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Sequence design and evaluation of the reproducibility of water-selective diffusion-weighted imaging of the breast at 3?T.
NMR Biomed
PUBLISHED: 02-10-2014
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Diffusion measurements derived from breast MRI can be adversely affected by unwanted signals from abundant fatty tissues if they are not suppressed adequately. To minimize this undesired contribution, we designed and optimized a water-selective diffusion-weighted imaging (DWI) sequence, which relies on spectrally selective excitation on the water resonance, obviating the need for fat suppression. As this method is more complex than standard DWI methods, we also report a test-retest study to evaluate its reproducibility. In this study, a spectrally selective Gaussian pulse on water resonance was combined with a pair of slice-selective adiabatic refocusing pulses for water-only DWI. Field map-based shimming and manual determination of the center frequency were used for water selection. The selectivity of the excitation pulse was optimized by a spectrally selective spectroscopy sequence based on the same principles. A test-retest study of 10 volunteers in two separate visits was used to evaluate its reproducibility. Our results from all subjects showed high-quality diffusion-weighted images of the breast without fat contamination. Mean apparent diffusion coefficients for b?=?0, 600?s/mm(2) and b?=?50, 600?s/mm(2) all showed good reproducibility, as 95% confidence intervals of the apparent diffusion coefficients were 4?×?10(-5) ?mm(2) /s and 5?×?10(-5) ?mm(2) /s and repeatability values were 1.09?×?10(-4) and 1.31?×?10(-4) , respectively. In conclusion, water-selective DWI is a feasible alternative to standard methods of DWI based on fat suppression. The added complexity of the method does not compromise the reproducibility of diffusion measurements in the breast.
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Fast and robust measurement of microstructural dimensions using temporal diffusion spectroscopy.
J. Magn. Reson.
PUBLISHED: 01-29-2014
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Mapping axon sizes non-invasively is of interest for neuroscientists and may have significant clinical potential because nerve conduction velocity is directly dependent on axon size. Current approaches to measuring axon sizes using diffusion-weighted MRI, e.g. q-space imaging with pulsed gradient spin echo (PGSE) sequences usually require long scan times and high q-values to detect small axons (diameter <2?m). The oscillating gradient spin echo (OGSE) method has been shown to be able to achieve very short diffusion times and hence may be able to detect smaller axons with high sensitivity. In the current study, OGSE experiments were performed to measure the inner diameters of hollow microcapillaries with a range of sizes (?1.5-19.3?m) that mimic axons in the human central nervous system. The results suggest that OGSE measurements, even with only moderately high frequencies, are highly sensitive to compartment sizes, and a minimum of two ADC values with different frequencies may be sufficient to extract the microcapillary size accurately. This suggests that the OGSE method may serve as a fast and robust measurement method for mapping axon sizes non-invasively.
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Identification of underserved areas for urologic cancer care.
Cancer
PUBLISHED: 01-16-2014
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The delivery of urologic oncology care is susceptible to regional variation. In the current study, the authors sought to define patterns of care for patients undergoing genitourinary cancer surgery to identify underserved areas for urologic cancer care in Washington State.
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Implementation of a "real-world" learning health care system: Washington State's Comparative Effectiveness Research Translation Network (CERTAIN).
Surgery
PUBLISHED: 01-15-2014
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Learning health care systems apply the experiences of prior patients to inform care and help to guide decision making for current patients. These systems should help to deliver more effective, efficient, and appropriate care. Most examples of learning systems derive from integrated care delivery systems and examples of such systems in the community at large have been lacking.
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Trends in followup imaging after adult pyeloplasty.
J. Urol.
PUBLISHED: 01-11-2014
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Although success rates are reported to be high, radiographic followup after pyeloplasty to correct ureteropelvic junction obstruction varies in intensity and modality. We characterized postoperative care after pyeloplasty to identify imaging trends.
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Individualized estimates of overdiagnosis in screen-detected prostate cancer.
J. Natl. Cancer Inst.
PUBLISHED: 01-07-2014
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The chance that a prostate cancer detected by screening is overdiagnosed (ie, it would not have been detected in the absence of screening) can vary widely depending on the patient's age and tumor characteristics. The purpose of this study is to use age, Gleason score, and prostate-specific antigen (PSA) level to help inform patients with screen-detected prostate cancers about the chances their cancers were overdiagnosed.
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Role of maximal endoscopic resection before cystectomy for invasive urothelial bladder cancer.
Clin Genitourin Cancer
PUBLISHED: 01-02-2014
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The aim of this study was to examine whether TUR of all visible endophytic tumors performed before RC, with or without NC, affects final pathologic staging.
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Nonresponse to Neoadjuvant Chemotherapy for Muscle-Invasive Urothelial Cell Carcinoma of the Bladder.
Clin Genitourin Cancer
PUBLISHED: 08-27-2013
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Cisplatin-based neoadjuvant chemotherapy (NC) is commonly used in the treatment of muscle-invasive urothelial cell carcinoma of the bladder (UC) and has been shown to improve survival. However, not all patients respond to NC, thus delaying the interval to potentially curative surgical therapy, risking disease progression and subjecting patients to potential morbidity from NC. In this study, we perform a retrospective analysis of patients who received NC prior to cystectomy to identify factors associated with nonresponse.
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Relation between brain architecture and mathematical ability in children: a DBM study.
Magn Reson Imaging
PUBLISHED: 08-27-2013
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Population-based studies indicate that between 5 and 9 percent of US children exhibit significant deficits in mathematical reasoning, yet little is understood about the brain morphological features related to mathematical performances. In this work, deformation-based morphometry (DBM) analyses have been performed on magnetic resonance images of the brains of 79 third graders to investigate whether there is a correlation between brain morphological features and mathematical proficiency. Group comparison was also performed between Math Difficulties (MD-worst math performers) and Normal Controls (NC), where each subgroup consists of 20 age and gender matched subjects. DBM analysis is based on the analysis of the deformation fields generated by non-rigid registration algorithms, which warp the individual volumes to a common space. To evaluate the effect of registration algorithms on DBM results, five nonrigid registration algorithms have been used: (1) the Adaptive Bases Algorithm (ABA); (2) the Image Registration Toolkit (IRTK); (3) the FSL Nonlinear Image Registration Tool; (4) the Automatic Registration Tool (ART); and (5) the normalization algorithm available in SPM8. The deformation field magnitude (DFM) was used to measure the displacement at each voxel, and the Jacobian determinant (JAC) was used to quantify local volumetric changes. Results show there are no statistically significant volumetric differences between the NC and the MD groups using JAC. However, DBM analysis using DFM found statistically significant anatomical variations between the two groups around the left occipital-temporal cortex, left orbital-frontal cortex, and right insular cortex. Regions of agreement between at least two algorithms based on voxel-wise analysis were used to define Regions of Interest (ROIs) to perform an ROI-based correlation analysis on all 79 volumes. Correlations between average DFM values and standard mathematical scores over these regions were found to be significant. We also found that the choice of registration algorithm has an impact on DBM-based results, so we recommend using more than one algorithm when conducting DBM studies. To the best of our knowledge, this is the first study that uses DBM to investigate brain anatomical features related to mathematical performance in a relatively large population of children.
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Pathologic Response Rates of Gemcitabine/Cisplatin versus Methotrexate/Vinblastine/Adriamycin/Cisplatin Neoadjuvant Chemotherapy for Muscle Invasive Urothelial Bladder Cancer.
Adv Urol
PUBLISHED: 08-05-2013
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Objectives. To compare pathologic outcomes after treatment with gemcitabine and cisplatin (GC) versus methotrexate, vinblastine, adriamycin, and cisplatin (MVAC) in the neoadjuvant setting. Methods. Data was retrospectively collected on 178 patients with T2-T4 bladder cancer who underwent radical cystectomy between 2003 and 2011. Outcomes of interest included those with complete response (pT0) and any response (?pT1). Odds ratios were calculated using multivariate logistic regression. Results. Compared to those who did not receive neoadjuvant chemotherapy, there were more patients with complete response (28% versus 9%, OR 3.11 (95% CI: 1.45-6.64), P = 0.03) and any response (52% versus 25%, OR 3.23 (95% CI: 1.21-8.64), P = 0.01). Seventy-two patients received GC (n = 41) or MVAC (n = 31). CR was achieved in 29% and 22% of GC and MVAC patients, respectively (multivariate OR 0.39, 95% CI 0.10-1.58). Any response (?pT1) was achieved in 56% of GC and 45% of MVAC patients (multivariate OR 0.45, 95% CI 0.12-1.71). Conclusions. We observed similar pathologic response rates for GC and MVAC neoadjuvant chemotherapy in this cohort of patients with muscle invasive urothelial cancer (MIBC). Our findings support the use of GC as an alternative regimen in the neoadjuvant setting.
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Exchange-mediated contrast in CEST and spin-lock imaging.
Magn Reson Imaging
PUBLISHED: 07-22-2013
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Magnetic resonance images of biological media based on chemical exchange saturation transfer (CEST) show contrast that depends on chemical exchange between water and other protons. In addition, spin-lattice relaxation rates in the rotating frame (R1?) are also affected by exchange, especially at high fields, and can be exploited to provide novel, exchange-dependent contrast. Here, we evaluate and compare the factors that modulate the exchange contrast for these methods using simulations and experiments on simple, biologically relevant samples.
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Gray matter parcellation constrained full brain fiber bundling with diffusion tensor imaging.
Med Phys
PUBLISHED: 07-05-2013
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Studying white matter fibers from diffusion tensor imaging (DTI) often requires them to be grouped into bundles that correspond to coherent anatomic structures, particularly bundles that connect cortical/subcortical basic units. However, traditional fiber clustering algorithms usually generate bundles with poor anatomic correspondence as they do not incorporate brain anatomic information into the clustering process. On the other hand, image registration-based bundling methods segment fiber bundles by referring to a coregistered atlas or template with prelabeled anatomic information, but these approaches suffer from the uncertainties introduced from misregistration and fiber tracking errors and thus the resulting bundles usually have poor coherence. In this work, a bundling algorithm is proposed to overcome the above issues.
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Quantitative magnetization transfer imaging of rodent glioma using selective inversion recovery.
NMR Biomed
PUBLISHED: 07-03-2013
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Magnetization transfer (MT) provides an indirect means to detect noninvasively variations in macromolecular contents in biological tissues, but, so far, there have been only a few quantitative MT (qMT) studies reported in cancer, all of which used off-resonance pulsed saturation methods. This article describes the first implementation of a different qMT approach, selective inversion recovery (SIR), for the characterization of tumor in vivo using a rodent glioma model. The SIR method is an on-resonance method capable of fitting qMT parameters and T1 relaxation time simultaneously without mapping B0 and B1 , which is very suitable for high-field qMT measurements because of the lower saturation absorption rate. The results show that the average pool size ratio (PSR, the macromolecular pool versus the free water pool) in rat 9?L glioma (5.7%) is significantly lower than that in normal rat gray matter (9.2%) and white matter (17.4%), which suggests that PSR is potentially a sensitive imaging biomarker for the assessment of brain tumor. Despite being less robust, the estimated MT exchange rates also show clear differences from normal tissues (19.7?Hz for tumors versus 14.8 and 10.2?Hz for gray and white mater, respectively). In addition, the influence of confounding effects, e.g. B1 inhomogeneity, on qMT parameter estimates is investigated with numerical simulations. These findings not only help to better understand the changes in the macromolecular contents of tumors, but are also important for the interpretation of other imaging contrasts, such as chemical exchange saturation transfer of tumors. Copyright © 2013 John Wiley & Sons, Ltd.
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Improving bladder cancer patient care: a pharmacoeconomic perspective.
Expert Rev Anticancer Ther
PUBLISHED: 06-19-2013
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Bladder cancer is the most expensive cancer per capita to treat in the US healthcare system. Substantial costs associated with the diagnosis, management and surveillance of bladder cancer account for the bulk of the expense; yet, for that cost, patients may not receive high-quality care. Herein the authors review the sources of expenditure associated with bladder cancer care, review population-level analyses of the quality of bladder cancer care in the USA, and discuss opportunities for quality improvement that may yield greater value for men and women newly diagnosed with bladder cancer.
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Comparison of Selective Parenchymal Clamping to Hilar Clamping During Robotic-assisted Laparoscopic Partial Nephrectomy.
Urology
PUBLISHED: 06-10-2013
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To compare perioperative outcomes after robotic-assisted laparoscopic partial nephrectomy (RALPN) with hilar clamping vs parenchymal clamping.
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T1? mapping of pediatric epiphyseal and articular cartilage in the knee.
J Magn Reson Imaging
PUBLISHED: 05-06-2013
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To evaluate the feasibility of measuring T1? values in epiphyseal cartilage in children, we have conducted a novel study of spin locking techniques. Adult articular cartilage has been widely studied with spin locking techniques by magnetic resonance imaging. However, no results are available for in vivo T1? imaging of developing cartilage.
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Repeatability and sensitivity of high resolution blood volume mapping in mouse kidney disease.
J Magn Reson Imaging
PUBLISHED: 05-03-2013
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To evaluate the repeatability of MRI-derived relative blood volume (RBV) measurements in mouse kidneys across subjects and days and to evaluate sensitivity of this approach to renal pathology.
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Imaging amide proton transfer and nuclear overhauser enhancement using chemical exchange rotation transfer (CERT).
Magn Reson Med
PUBLISHED: 05-01-2013
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This study investigates amide proton transfer (APT) and nuclear overhauser enhancement (NOE) in phantoms and 9L tumors in rat brains at 9.4 Tesla, using a recently developed method that can isolate different contributions to exchange.
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A comprehensive analysis of transfection-assisted delivery of iron oxide nanoparticles to dendritic cells.
Nanomedicine
PUBLISHED: 04-30-2013
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Polylysine (PL) has been used to facilitate dendritic cell (DC) uptake of super paramagnetic iron oxide (SPIO) nanoparticles for use in magnetic resonance imaging (MRI). In this work, we examined the effect of PL on cell toxicity and induction of cell maturation as manifested by the up-regulation of surface molecules. We found that PL became toxic to bone marrow-derived DCs (BMDCs) at the 10 ?g/ml threshold. Incubation of BMDCs with 20 ?g/ml of PL for 1h resulted in approximately 90% cell death. However, addition of SPIO nanoparticles rescued DCs from PL-induced death as the combination of SPIO with PL did not cause cytotoxicity until the PL concentration was 1000 ?g/ml. Prolonged exposure to PL induced BMDC maturation as noted by the expression of surface molecules such as MHC class II, CD40, CCR7 and CD86. However, the combination of SPIO and PL did not induce BMDC maturation at 1h. However prolonged exposure to SPIO nanoparticles induced CD40 expression and protein expression of TNF? and KC. The data suggest that the use of PL to enhance the labeling of DCs with SPIO nanoparticles is a dedicated work. Appropriate calibration of the incubation time and concentrations of PL and SPIO nanoparticles is crucial to the development of MRI technology for noninvasive imaging of DCs in vivo.
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Risk factors for renal cell carcinoma in the VITAL study.
J. Urol.
PUBLISHED: 04-29-2013
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The incidence of renal cell carcinoma is increasing worldwide. Cited risk factors include obesity, smoking and hypertension but few others have been confirmed in prospective studies. We used a prospective cohort to validate established renal cell carcinoma risk factors and evaluate more controversial risk factors for incident renal cell carcinoma.
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Prospective real-time head motion correction using inductively coupled wireless NMR probes.
Magn Reson Med
PUBLISHED: 04-23-2013
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Head motion continues to be a major source of artifacts and data quality degradation in MRI. The goal of this work was to develop and demonstrate a novel technique for prospective, 6 degrees of freedom (6DOF) rigid body motion estimation and real-time motion correction using inductively coupled wireless nuclear magnetic resonance (NMR) probe markers.
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The relationship of anatomical and functional connectivity to resting-state connectivity in primate somatosensory cortex.
Neuron
PUBLISHED: 04-15-2013
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Studies of resting-state activity in the brain have provoked critical questions about the brains functional organization, but the biological basis of this activity is not clear. Specifically, the relationships between interregional correlations in resting-state measures of activity, neuronal functional connectivity and anatomical connectivity are much debated. To investigate these relationships, we have examined both anatomical and steady-state functional connectivity within the hand representation of primary somatosensory cortex (areas 3b and 1) in anesthetized squirrel monkeys. The comparison of three data sets (fMRI, electrophysiological, and anatomical) indicate two primary axes of information flow within the SI: prominent interdigit interactions within area 3b and predominantly homotopic interactions between area 3b and area 1. These data support a strikingly close relationship between baseline functional connectivity and anatomical connections. This study extends findings derived from large-scale cortical networks to the realm of local millimeter-scale networks.
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Using dynamic contrast-enhanced magnetic resonance imaging data to constrain a positron emission tomography kinetic model: theory and simulations.
Int J Biomed Imaging
PUBLISHED: 04-08-2013
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We show how dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) data can constrain a compartmental model for analyzing dynamic positron emission tomography (PET) data. We first develop the theory that enables the use of DCE-MRI data to separate whole tissue time activity curves (TACs) available from dynamic PET data into individual TACs associated with the blood space, the extravascular-extracellular space (EES), and the extravascular-intracellular space (EIS). Then we simulate whole tissue TACs over a range of physiologically relevant kinetic parameter values and show that using appropriate DCE-MRI data can separate the PET TAC into the three components with accuracy that is noise dependent. The simulations show that accurate blood, EES, and EIS TACs can be obtained as evidenced by concordance correlation coefficients >0.9 between the true and estimated TACs. Additionally, provided that the estimated DCE-MRI parameters are within 10% of their true values, the errors in the PET kinetic parameters are within approximately 20% of their true values. The parameters returned by this approach may provide new information on the transport of a tracer in a variety of dynamic PET studies.
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Sensorimotor-independent prefrontal activity during response inhibition.
Hum Brain Mapp
PUBLISHED: 03-27-2013
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A network of brain regions involving the ventral inferior frontal gyrus/anterior insula (vIFG/AI), presupplementary motor area (pre-SMA) and basal ganglia has been implicated in stopping impulsive, unwanted responses. However, whether this network plays an equal role in response inhibition under different sensorimotor contexts has not been tested systematically. Here, we conducted an fMRI experiment using the stop signal task, a sensorimotor task requiring occasional withholding of the planned response upon the presentation of a stop signal. We manipulated both the sensory modality of the stop signal (visual versus auditory) and the motor response modality (hand versus eye). Results showed that the vIFG/AI and the preSMA along with the right middle frontal gyrus were commonly activated in response inhibition across the various sensorimotor conditions. Our findings provide direct evidence for a common role of these frontal areas, but not striatal areas in response inhibition independent of the sensorimotor contexts. Nevertheless, these three frontal regions exhibited different activation patterns during successful and unsuccessful stopping. Together with the existing evidence, we suggest that the vIFG/AI is involved in the early stages of stopping such as triggering the stop process while the preSMA may play a role in regulating other cortical and subcortical regions involved in stopping. Hum Brain Mapp, 2013. © 2013 Wiley Periodicals, Inc.
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Synthesis of Brightly PEGylated Luminescent Magnetic Upconversion Nanophosphors for Deep Tissue and Dual MRI Imaging.
Small
PUBLISHED: 03-15-2013
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A method is developed to fabricate monodispersed biocompatible Yb/Er or Yb/Tm doped ?-NaGdF4 upconversion phosphors using polyelectrolytes to prevent irreversible particle aggregation during conversion of the precursor, Gd2 O(CO3 )2 •H2 O:Yb/Er or Yb/Tm, to ?-NaGdF4 :Yb/Er or Yb/Tm. The polyelectrolyte on the outer surface of nanophosphors also provided an amine tag for PEGylation. This method is also employed to fabricate PEGylated magnetic upconversion phosphors with Fe3 O4 as the core and ?-NaGdF4 as a shell. These magnetic upconversion nanophosphors have relatively high saturation magnetization (7.0 emu g(-1) ) and magnetic susceptibility (1.7 × 10(-2) emu g(-1) Oe(-1) ), providing them with large magnetophoretic mobilities. The magnetic properties for separation and controlled release in flow, their optical properties for cell labeling, deep tissue imaging, and their T1 - and T2 -weighted magnetic resonance imaging (MRI) relaxivities are studied. The magnetic upconversion phosphors display both strong magnetophoresis, dual MRI imaging (r1 = 2.9 mM(-1) s(-1) , r2 = 204 mM(-1) s(-1) ), and bright luminescence under 1 cm chicken breast tissue.
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A novel reporter system for molecular imaging and high-throughput screening of anticancer drugs.
Chembiochem
PUBLISHED: 03-11-2013
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Apoptosis is irreversible programmed cell death, characterized by a cellular cascade activation of caspase 3, which subsequently degrades proteins and other components of cells with a motif sequence. Here we report a novel reporter system to detect apoptosis, growth arrest, and cell death based on controlled and self-amplified protein degradation. The key element of the reporter system is an apoptotic sensor chimerical protein which consists of three components: procaspase 3, ubiquitin (Ub), and a strong consensus sequence of N-degron. Between each of these units is a DEVD (Asp-Glu-Val-Asp) sequence, which acts as the cleavage target of caspase 3. This non-conventional signal loss approach is much more sensitive than other native methods that are based on signal gain. The superior sensitivity is demonstrated by its effective application in 386-well high-throughput screening (HTS) with low drug concentrations and a short incubation time. The HTS selection process using this reporter system is very simple and economic. The simplicity eliminates potential errors introduced by multiple steps; there is no need for any substrate. Furthermore, the cells in the assay need not be disrupted, and the morphology of the cells can provide additional information on mechanisms. After HTS, the intact cells can also be used for other analytic analysis. This system thus has a potentially important role in the discovery and development of new anticancer drugs. It also appears to be very versatile, can be used both in vitro and in vivo with different linked reporter genes, and can be used for a variety of imaging applications.
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Downstream complications following urinary diversion.
J. Urol.
PUBLISHED: 03-07-2013
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Surveillance following urinary diversion should be tailored to capture complications downstream from the initial reconstruction. Most analyses of the morbidity associated with urinary diversion are restricted to the index admission or the immediate postoperative period. We characterize the long-term medical and surgical complications and burden of health care use after urinary diversion.
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Quality of life in women undergoing urinary diversion for bladder cancer: results of a multicenter study among long-term disease-free survivors.
Health Qual Life Outcomes
PUBLISHED: 02-25-2013
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Women undergoing radical cystectomy (RC) and urinary diversion for bladder cancer experience substantial limitations in health-related quality of life (HRQOL). However, the level of discomfort caused by different urinary diversion has been never evaluated in long term survivors. The aim of this multicenter study is to evaluate differences in HRQOL among recurrence-free women undergoing cutaneous ureterostomy (CUS), Brickers ileal conduit (BK-IC) and Orthotopic neobladder VIP (ONB-VIP) in disease-free females treated with radical cystectomy (RC), with long-term follow up (mean 60.1 months; range 36-122 months).
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Effects of screening on radical prostatectomy efficacy: the prostate cancer intervention versus observation trial.
J. Natl. Cancer Inst.
PUBLISHED: 02-14-2013
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The Scandinavian Prostate Cancer Group Study Number 4 (SPCG-4) trial showed that radical prostatectomy (RP) reduced prostate cancer deaths with an absolute mortality difference (AMD) between the RP and watchful waiting arms of 6.1% (95% confidence interval [CI] = 0.2% to 12.0%) after 15 years. In the United States, the Prostate Cancer Intervention Versus Observation Trial (PIVOT) produced an AMD of 3% (95% CI = -1.1% to 6.5%) after 12 years. It is not known whether a higher frequency of screen detection in PIVOT explains the lower AMD.
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The costs of non-muscle invasive bladder cancer.
Urol. Clin. North Am.
PUBLISHED: 02-13-2013
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Bladder cancer is a common diagnosis, affecting 70,000 Americans each year. Because the diagnosis, management, and long-term follow-up of non-muscle invasive bladder cancer requires advanced imaging and invasive testing, economic evaluations have shown bladder cancer to be the costliest cancer to treat in the US on a per capita basis. Adjunctive tests for surveillance have not obviated the need for cystoscopy and cytology. Indirect costs to patients include loss of work, decreased productivity, and diminished quality of life associated with diagnosis, treatment, and surveillance. Improved value may be achieved with better compliance with evidence-based practices for non-muscle invasive bladder cancer care.
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Comparative effectiveness of alternative prostate-specific antigen--based prostate cancer screening strategies: model estimates of potential benefits and harms.
Ann. Intern. Med.
PUBLISHED: 02-06-2013
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The U.S. Preventive Services Task Force recently concluded that the harms of existing prostate-specific antigen (PSA) screening strategies outweigh the benefits.
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A comparison and evaluation of reduced-FOV methods for multi-slice 7T human imaging.
Magn Reson Imaging
PUBLISHED: 01-30-2013
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Eight different reduced field-of-view (FOV) MRI techniques suitable for high field human imaging were implemented, optimized, and evaluated at 7T. These included selective Inner-Volume Imaging (IVI) based methods, and Outer-Volume Suppression (OVS) techniques, some of which were previously unexplored at ultra-high fields. Design considerations included use of selective composite excitation and adiabatic refocusing radio-frequency (RF) pulses to address B1 inhomogeneities, twice-refocused spin echo techniques, frequency-modulated pulses to sharply define suppressed regions, and pulse sequence designs to improve SNR in multi-slice scans. The different methods were quantitatively compared in phantoms and in vivo human brain images to provide measurements of relative signal to noise ratio (SNR), power deposition (specific absorption rate, SAR), suppression of signal, artifact strength and prevalence, and general image quality. Multi-slice signal losses in out-of-slice locations were simulated for IVI methods, and then measured experimentally across a range of slice numbers. Corrections for B1 nonuniformities demonstrated an improved SNR and a reduction in artifact power in the reduced-FOV, but produced an elevated SAR. Multi-slice sequences with reordering of pulses in traditional and twice-refocused IVI techniques demonstrated an improved SNR compared to conventional methods. The combined results provide a basis for use of reduced-FOV techniques for human imaging localized to a small FOV at 7T.
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Dispersion of relaxation rates in the rotating frame under the action of spin-locking pulses and diffusion in inhomogeneous magnetic fields.
Magn Reson Med
PUBLISHED: 01-24-2013
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A method is described for characterizing magnetically inhomogeneous media and the spatial scales of intrinsic susceptibility variations within samples. The rate of spin-lattice relaxation in the rotating frame, R1? , is affected by diffusion effects to a degree that depends on the magnitude of an applied spin-locking field. Appropriate analysis of the dispersion of R1? with locking field may be used to characterize susceptibility variations in inhomogeneous tissues.
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Spatio-temporal correlation tensors reveal functional structure in human brain.
PLoS ONE
PUBLISHED: 01-01-2013
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Resting state functional magnetic resonance imaging (fMRI) has been commonly used to measure functional connectivity between cortical regions, while diffusion tensor imaging (DTI) can be used to characterize structural connectivity of white matter tracts. In principle combining resting state fMRI and DTI data could allow characterization of structure-function relations of distributed neural networks. However, due to differences in the biophysical origins of their signals and in the tissues to which they apply, there has been no direct integration of these techniques to date. We demonstrate that MRI signal variations and power spectra in a resting state are largely comparable between gray matter and white matter, that there are temporal correlations of fMRI signals that persist over long distances within distinct white matter structures, and that neighboring intervoxel correlations of low frequency resting state signals showed distinct anisotropy in many regions. These observations suggest that MRI signal variations from within white matter in a resting state may convey similar information as their corresponding fluctuations of MRI signals in gray matter. We thus derive a local spatio-temporal correlation tensor which captures directional variations of resting-state correlations and which reveals distinct structures in both white and gray matter. This novel concept is illustrated with in vivo experiments in a resting state, which demonstrate the potential of the technique for mapping the functional structure of neural networks and for direct integration of structure-function relations in the human brain.
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Identification of promethazine as an amyloid-binding molecule using a fluorescence high-throughput assay and MALDI imaging mass spectrometry.
Neuroimage Clin
PUBLISHED: 01-01-2013
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The identification of amyloid-binding compounds is a crucial step in the development of imaging probes and therapeutics for the detection and cure of Alzheimers disease. Unfortunately, the process typically lags during the translation from in vitro to in vivo studies due to the impenetrable nature of the blood brain barrier (BBB). Here, we integrate fluorescence assay with MALDI imaging mass spectrometry to screen known compounds and repurpose their properties to enable the second function of binding to amyloid plaques. Through this approach, we identified an antihistamine compound, promethazine, that can bind to amyloid plaques. Finally, we demonstrate that promethazine is retained in the amyloid-burdened brain compared to a normal brain and that its distribution within the brain corroborates with that of amyloid plaques.
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On the origins of signal variance in FMRI of the human midbrain at high field.
PLoS ONE
PUBLISHED: 01-01-2013
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Functional Magnetic Resonance Imaging (fMRI) in the midbrain at 7 Tesla suffers from unexpectedly low temporal signal to noise ratio (TSNR) compared to other brain regions. Various methodologies were used in this study to quantitatively identify causes of the noise and signal differences in midbrain fMRI data. The influence of physiological noise sources was examined using RETROICOR, phase regression analysis, and power spectral analyses of contributions in the respiratory and cardiac frequency ranges. The impact of between-shot phase shifts in 3-D multi-shot sequences was tested using a one-dimensional (1-D) phase navigator approach. Additionally, the effects of shared noise influences between regions that were temporally, but not functionally, correlated with the midbrain (adjacent white matter and anterior cerebellum) were investigated via analyses with regressors of no interest. These attempts to reduce noise did not improve the overall TSNR in the midbrain. In addition, the steady state signal and noise were measured in the midbrain and the visual cortex for resting state data. We observed comparable steady state signals from both the midbrain and the cortex. However, the noise was 2-3 times higher in the midbrain relative to the cortex, confirming that the low TSNR in the midbrain was not due to low signal but rather a result of large signal variance. These temporal variations did not behave as known physiological or other noise sources, and were not mitigated by conventional strategies. Upon further investigation, resting state functional connectivity analysis in the midbrain showed strong intrinsic fluctuations between homologous midbrain regions. These data suggest that the low TSNR in the midbrain may originate from larger signal fluctuations arising from functional connectivity compared to cortex, rather than simply reflecting physiological noise.
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Improving measurement of functional connectivity through decreasing partial volume effects at 7 T.
Neuroimage
PUBLISHED: 08-26-2011
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Several applications of fMRI at high field have taken advantage of the increased BOLD contrast to increase spatial resolution, but the potential benefits of higher fields for detecting and analyzing functional connectivity have largely been unexplored. We measured the influence of spatial resolution at 7 T on estimates of functional connectivity through decreased partial volume averaging. Ten subjects were imaged at 7 T with a range of spatial resolutions (1×1×2 mm to 3×3×2 mm) during performance of a finger tapping task and in the resting state. We found that resting state correlations within the sensory-motor system increase as voxel dimensions decreased from 3×3×2 mm to 1×1×2 mm, whereas connectivity to other brain regions was unaffected. This improvement occurred even as overall signal to noise ratios decrease. Our data suggest that this increase may be due to decreased partial volume averaging, and that functional connectivity within the primary seed region is heterogeneous on the scale of single voxels.
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A novel AIF tracking method and comparison of DCE-MRI parameters using individual and population-based AIFs in human breast cancer.
Phys Med Biol
PUBLISHED: 08-12-2011
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Quantitative analysis of dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) data requires the accurate determination of the arterial input function (AIF). A novel method for obtaining the AIF is presented here and pharmacokinetic parameters derived from individual and population-based AIFs are then compared. A Philips 3.0 T Achieva MR scanner was used to obtain 20 DCE-MRI data sets from ten breast cancer patients prior to and after one cycle of chemotherapy. Using a semi-automated method to estimate the AIF from the axillary artery, we obtain the AIF for each patient, AIF(ind), and compute a population-averaged AIF, AIF(pop). The extended standard model is used to estimate the physiological parameters using the two types of AIFs. The mean concordance correlation coefficient (CCC) for the AIFs segmented manually and by the proposed AIF tracking approach is 0.96, indicating accurate and automatic tracking of an AIF in DCE-MRI data of the breast is possible. Regarding the kinetic parameters, the CCC values for K(trans), v(p) and v(e) as estimated by AIF(ind) and AIF(pop) are 0.65, 0.74 and 0.31, respectively, based on the region of interest analysis. The average CCC values for the voxel-by-voxel analysis are 0.76, 0.84 and 0.68 for K(trans), v(p) and v(e), respectively. This work indicates that K(trans) and v(p) show good agreement between AIF(pop) and AIF(ind) while there is a weak agreement on v(e).
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What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

How does it work?

We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

Video X seems to be unrelated to Abstract Y...

In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.