32 research outputs found
Computerâassisted Curie scoring for metaiodobenzylguanidine (MIBG) scans in patients with neuroblastoma
BackgroundRadiolabeled metaiodobenzylguanidine (MIBG) is sensitive and specific for detecting neuroblastoma. The extent of MIBGâavid disease is assessed using Curie scores. Although Curie scoring is prognostic in patients with highârisk neuroblastoma, there is no standardized method to assess the response of specific sites of disease over time. The goal of this study was to develop approaches for Curie scoring to facilitate the calculation of scores and comparison of specific sites on serial scans.ProcedureWe designed three semiautomated methods for determining Curie scores, each with increasing degrees of computer assistance. Method A was based on visual assessment and tallying of MIBGâavid lesions. For method B, scores were tabulated from a schematic that associated anatomic regions to MIBGâpositive lesions. For method C, an anatomic mesh was used to mark MIBGâpositive lesions with automatic assignment and tallying of scores. Five imaging physicians experienced in MIBG interpretation scored 38 scans using each method, and the feasibility and utility of the methods were assessed using surveys.ResultsThere was good reliability between methods and observers. The userâinterface methods required 57 to 110 seconds longer than the visual method. Imaging physicians indicated that it was useful that methods B and C enabled tracking of lesions. Imaging physicians preferred method B to method C because of its efficiency.ConclusionsWe demonstrate the feasibility of semiautomated approaches for Curie score calculation. Although more time was needed for strategies B and C, the ability to track and document individual MIBGâpositive lesions over time is a strength of these methods.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146464/1/pbc27417.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146464/2/pbc27417_am.pd
Connectivity mapping (ssCMap) to predict A20-inducing drugs and their antiinflammatory action in cystic fibrosis
Cystic fibrosis (CF) lung disease is characterized by chronic and exaggerated inflammation in the airways. Despite recent developments to therapeutically overcome the underlying functional defect in the cystic fibrosis transmembrane conductance regulator, there is still an unmet need to also normalize the inflammatory response. The prolonged and heightened inflammatory response in CF is, in part, mediated by a lack of intrinsic down-regulation of the proinflammatory NF-ÎșB pathway. We have previously identified reduced expression of the NF-ÎșB down-regulator A20 in CF as a key target to normalize the inflammatory response. Here, we have used publicly available gene array expression data together with a statistically significant connectionsâ map (sscMap) to successfully predict drugs already licensed for the use in humans to induce A20 mRNA and protein expression and thereby reduce inflammation. The effect of the predicted drugs on A20 and NF-ÎșB(p65) expression (mRNA) as well as proinflammatory cytokine release (IL-8) in the presence and absence of bacterial LPS was shown in bronchial epithelial cells lines (16HBE14oâ, CFBE41oâ) and in primary nasal epithelial cells from patients with CF (Phe508del homozygous) and non-CF controls. Additionally, the specificity of the drug action on A20 was confirmed using cell lines with tnfαip3 (A20) knockdown (siRNA). We also show that the A20-inducing effect of ikarugamycin and quercetin is lower in CF-derived airway epithelial cells than in non-CF cells
Electron transfer kinetics on natural crystals of MoS2Â and graphite
Here, we evaluate the electrochemical performance of sparsely studied natural crystals of molybdenite and graphite, which have increasingly been used for fabrication of next generation monolayer molybdenum disulphide and graphene energy storage devices. Heterogeneous electron transfer kinetics of several redox mediators, including Fe(CN)63â/4â, Ru(NH3)63+/2+ and IrCl62â/3â are determined using voltammetry in a micro-droplet cell. The kinetics on both materials are studied as a function of surface defectiveness, surface ageing, applied potential and illumination. We find that the basal planes of both natural MoS2 and graphite show significant electroactivity, but a large decrease in electron transfer kinetics is observed on atmosphere-aged surfaces in comparison to in situ freshly cleaved surfaces of both materials. This is attributed to surface oxidation and adsorption of airborne contaminants at the surface exposed to an ambient environment. In contrast to semimetallic graphite, the electrode kinetics on semiconducting MoS2 are strongly dependent on the surface illumination and applied potential. Furthermore, while visibly present defects/cracks do not significantly affect the response of graphite, the kinetics on MoS2 systematically accelerate with small increase in disorder. These findings have direct implications for use of MoS2 and graphene/graphite as electrode materials in electrochemistry-related applications
The Brain Tumor Segmentation (BraTS) Challenge 2023: Focus on Pediatrics (CBTN-CONNECT-DIPGR-ASNR-MICCAI BraTS-PEDs)
Pediatric tumors of the central nervous system are the most common cause of
cancer-related death in children. The five-year survival rate for high-grade
gliomas in children is less than 20\%. Due to their rarity, the diagnosis of
these entities is often delayed, their treatment is mainly based on historic
treatment concepts, and clinical trials require multi-institutional
collaborations. The MICCAI Brain Tumor Segmentation (BraTS) Challenge is a
landmark community benchmark event with a successful history of 12 years of
resource creation for the segmentation and analysis of adult glioma. Here we
present the CBTN-CONNECT-DIPGR-ASNR-MICCAI BraTS-PEDs 2023 challenge, which
represents the first BraTS challenge focused on pediatric brain tumors with
data acquired across multiple international consortia dedicated to pediatric
neuro-oncology and clinical trials. The BraTS-PEDs 2023 challenge focuses on
benchmarking the development of volumentric segmentation algorithms for
pediatric brain glioma through standardized quantitative performance evaluation
metrics utilized across the BraTS 2023 cluster of challenges. Models gaining
knowledge from the BraTS-PEDs multi-parametric structural MRI (mpMRI) training
data will be evaluated on separate validation and unseen test mpMRI dataof
high-grade pediatric glioma. The CBTN-CONNECT-DIPGR-ASNR-MICCAI BraTS-PEDs 2023
challenge brings together clinicians and AI/imaging scientists to lead to
faster development of automated segmentation techniques that could benefit
clinical trials, and ultimately the care of children with brain tumors
Increasing frailty is associated with higher prevalence and reduced recognition of delirium in older hospitalised inpatients: results of a multi-centre study
Purpose:
Delirium is a neuropsychiatric disorder delineated by an acute change in cognition, attention, and consciousness. It is common, particularly in older adults, but poorly recognised. Frailty is the accumulation of deficits conferring an increased risk of adverse outcomes. We set out to determine how severity of frailty, as measured using the CFS, affected delirium rates, and recognition in hospitalised older people in the United Kingdom.
Methods:
Adults over 65 years were included in an observational multi-centre audit across UK hospitals, two prospective rounds, and one retrospective note review. Clinical Frailty Scale (CFS), delirium status, and 30-day outcomes were recorded.
Results:
The overall prevalence of delirium was 16.3% (483). Patients with delirium were more frail than patients without delirium (median CFS 6 vs 4). The risk of delirium was greater with increasing frailty [OR 2.9 (1.8â4.6) in CFS 4 vs 1â3; OR 12.4 (6.2â24.5) in CFS 8 vs 1â3]. Higher CFS was associated with reduced recognition of delirium (OR of 0.7 (0.3â1.9) in CFS 4 compared to 0.2 (0.1â0.7) in CFS 8). These risks were both independent of age and dementia.
Conclusion:
We have demonstrated an incremental increase in risk of delirium with increasing frailty. This has important clinical implications, suggesting that frailty may provide a more nuanced measure of vulnerability to delirium and poor outcomes. However, the most frail patients are least likely to have their delirium diagnosed and there is a significant lack of research into the underlying pathophysiology of both of these common geriatric syndromes
Parametric Mapping of Oxygen Activity in Human Placenta across Gestation using in utero BOLD imaging
International audienceSynopsis We present here, for the rst time, parametric maps of oxygen activity in normal human placenta using in utero functional MR imaging. Our method highlights anatomical and gestational age dependent patterns in placental activity. These maps can be used to gain insight into normative placental function and identifying insuucient or abnormal placental functioning at various points in gestation. Introduction Our current understanding of placental development and function is based on animal imaging and ex-vivo studies of placenta obtained after delivery or interrupted pregnancies. Previous human imaging studies were restricted to understanding hyperoxygentation or adverse developmental conditions such as fetal growth restriction (FGR), placental previa, placenta accrete, etc.. These studies strongly indicate that improved in-vivo delineation of vasculogenesis and angiogenesis of the placenta has the potential to provide better insight into the pathogenesis of placental dysfunction. By leveraging non-invasive, high-resolution imaging capabilities of in utero fetal MRI, we present a spatiotemporal analysis of normative fetoplacental oxygenation patterns at various time points in gestation. We hypothesize that (a) spatial variance of BOLD placental signal would age-dependent , and (b) that serial parametric maps of BOLD signal would reveal important anatomic insights about the feto-placental and maternal circulation. Methods We conducted a prospective two-site study of placental development in which 20 maternal subjects with normal pregnancies were recruited between 26-37 gestational weeks (GW). Images were acquired using 3T Philips Ingenia or Siemens Skyra machines. Over a 5-10 minute total acquisition time, BOLD images (1.5 mm x 1.5 mm x 4 mm) were acquired using an EPI sequence in blocks of 60 images with TR/TE = 3000/35 ms, ip angle = 90°. In addition, a high resolution T2 weighted images (1 mm x 1 mm x 3 mm) were acquired using a 3D FFE sequence (TR/TE = 3.1/1.6 ms, ip angle = 75°). BOLD images were processed using the "Functional MRI of the Brain" Software Library (FSL). The BOLD signal was motion corrected, co registered to the T2 images and ltered to remove physiological noise such as cardiac, breathing and metabolic uctuations. An F test was used to test the relationship between spatial signal variations and gestational age. To compare oxygenation levels within the placenta, we computed the normalized BOLD values after averaging the amplitude of the BOLD signal over the duration of the study for each time point. Results We found that the spatial variance of the BOLD signal was age dependent (F= 2.25, p<0.001). We then generated parametric maps of oxygen activity in a subset of fetuses at various gestational ages. Figure 1 shows the mean BOLD signal values across the placenta between 26 and 36 GW. The parametric mapping delineates two distinct regions of high oxygenation activity, corresponding to the fetal side (adjacent to the site of umbilical cord attachment) and the maternal side (along the uterine wall). The regions of high activity also occurred in speciic clusters. The size and number if these high-activity regions increased from 26 to 28 GW. We then observed a drop in the number and size of these regions at 29 GW with a further decrease at 36 GW. Discussion Our results clearly indicate that oxygenation is spatially heterogenous across the placenta with oxygen activity concentrated at speciic anatomical locations. The spatial variance in oxygen activity is also age-dependent. The reduction in size and number of high activity clusters at 29 GW and beyond correlates with the involution of the placenta in the third trimester leading to birth. Lower BOLD signal values in the middle of the placenta could correspond to the lack of deoxyhemoglobin as these regions only transport oxygen to the umbilical cord. The oxygenation maps provide a baseline for how oxygen activity occurs and changes over gestation giving us a better understanding of fetoplacental haemodynamics and placental transfer. They may also be used to identify abnormal oxygenation patterns in a placenta thereby acting as a marker for early detection of FGR or insuucient placental function. Conclusion There are age-dependent, spatial variances of BOLD signal in the placenta which may correlate with angiogenesis. Using parametric mapping of placental BOLD signal, we have demonstrated that placental oxygenation activity is concentrated at speciic anatomical locations associated with feto-maternal oxygen exchange. The non-invasive and repeatable methods presented here may facilitate better predictions of placental dysfunction in high-risk pregnancies and inform perinatal care
Influence of ultrathin poly-(3,4-ethylenedioxythiophene) (PEDOT) film supports on the electrodeposition and electrocatalytic activity of discrete platinum nanoparticles
Coating a carbon electrode surface, specifically highly oriented pyrolytic graphite (HOPG) with an ultrathin film of poly-(3,4-ethylenedioxythiophene), PEDOT, provides a support on which a high density of uniformly dispersed Pt nanoparticles (NPs) can readily be formed by electrodeposition. The NPs tend to be much smaller, have a higher surface coverage, better dispersion and show a much lower tendency to aggregate, than Pt NPs produced under identical electrochemical conditions on HOPG alone. The electrocatalytic activity of the NPs was investigated for methanol (MeOH) and formic acid (HCOOH) oxidation. Significantly, for similarly prepared particles, Pt NP-PEDOT arrays exhibited higher catalytic activity (in terms of current density, based on the Pt area), towards MeOH oxidation, by an order of magnitude, and towards HCOOH oxidation at high potentials, than Pt NPs supported on native HOPG. These findings can be rationalised in terms of the enhanced oxidation of adsorbed CO, a key reaction intermediate and a catalyst poison. This research provides strong evidence that employing conducting polymers, such as PEDOT, as a support substrate, can greatly improve particular catalytic reactions, allowing for better catalyst utilisation in fuel cell technology
Active sites for outer-sphere, inner-sphere, and complex multistage electrochemical reactions at polycrystalline boron-doped diamond electrodes (pBDD) revealed with scanning electrochemical cell microscopy (SECCM)
The local rate of heterogeneous electron transfer (HET) at polycrystalline boron-doped diamond (pBDD) electrodes has been visualized at high spatial resolution for various aqueous electrochemical reactions, using scanning electrochemical cell microscopy (SECCM), which is a technique that uses a mobile pipet-based electrochemical cell as an imaging probe. As exemplar systems, three important classes of electrode reactions have been investigated: outer-sphere (one-electron oxidation of ferrocenylmethyltrimethylammonium (FcTMA+)), inner-sphere (one-electron oxidation of Fe2+), and complex processes with coupled electron transfer and chemical reactions (oxidation of serotonin). In all cases, the pattern of reactivity is similar: the entire pBDD surface is electroactive, but there are variations in activity between different crystal facets which correlate directly with differences in the local dopant level, as visualized qualitatively by field-emission scanning electron microscopy (FE-SEM). No evidence was found for enhanced activity at grain boundaries for any of the reactions. The case of serotonin oxidation is particularly interesting, as this process is known to lead to deterioration of the electrodes, because of blocking by reaction products, and therefore cannot be studied with conventional scanning electrochemical probe microscopy (SEPM) techniques. Yet, we have found this system nonproblematic to study, because the meniscus of the scanning pipet is only in contact with the surface investigated for a brief time and any blocking product is left behind as the pipet moves to a new location. Thus, SECCM opens up the possibility of investigating and visualizing much more complex heterogeneous electrode reactions than possible presently with other SEPM techniques
Recommended from our members
Imaging of pediatric adrenal tumors: A COG Diagnostic Imaging Committee/SPR Oncology Committee White Paper
Adrenal tumors other than neuroblastoma are uncommon in children. The most frequently encountered are adrenocortical carcinoma and pheochromocytoma. This paper offers consensus recommendations for imaging of pediatric patients with a known or suspected primary adrenal malignancy other than neuroblastoma at diagnosis and during follow-up