Mesenchymal Stromal Cells Facilitate Tip Cell Fusion Downstream of BMP-Mediated Venous Angiogenesis-Brief Report.

BACKGROUND: The goal of this study was to identify and characterize cell-cell interactions that facilitate endothelial tip cell fusion downstream of BMP (bone morphogenic protein)-mediated venous plexus formation. METHODS: High resolution and time-lapse imaging of transgenic reporter lines and loss-of-function studies were carried out to study the involvement of mesenchymal stromal cells during venous angiogenesis. RESULTS: BMP-responsive stromal cells facilitate timely and precise fusion of venous tip cells during developmental angiogenesis. CONCLUSIONS: Stromal cells are required for anastomosis of venous tip cells in the embryonic caudal hematopoietic tissue.

Left Ventricular Mass Index in End-Stage Renal Disease Patients during Hemodialysis and Continuous Ambulatory Peritoneal Dialysis.

Background: One of the primary reasons for high mortality in end-stage renal disease (ESRD) is cardiovascular disease in patients with renal replacement therapy (RRT). Left ventricular hypertrophy (LVH) significantly predicts mortality and cardiovascular events. Objectives: We assess the left ventricular mass index change in two dialysis methods: hemodialysis (HD) and continuous ambulatory peritoneal dialysis (CAPD). The factors associated with increased left ventricular mass index (LVMI). Materials and Methods: We recruit more than 50 HD patients and 45 CAPD patients with LVH of similar age, gender, dialysis duration, and LVMI for one-year follow-up. Results: The LVMI in the group of HD patients after one year increased from 180.28 ± 45.32 g/m2 to 212.58 ± 66.22 g/m2 (p = 0.001), while the LVMI in the group of patients with CAPD increased from 190.16 ± 66.01 g/m2 to 197.42 ± 78 g/m2 (p = 0.32). Multivariable logistic regression analysis, we demonstrated that dialysis by HD (ß = -1,167, 95% CI: 0.104-0.938, p = 0.036) and anemia treatment lower the goals (ß = 1.9566, 95% CI: 1.466-34.094, p = 0.015) were two factors associated with the progression of the LVMI. Conclusion: The LVH of end-stage renal disease patients with HD treatment is worse than CAPD treatment after a follow-up in one year. Dialysis by periodic hemodialysis and anemia treatment that fails to achieve the goal are risk factors associated with increased progression of LVMI in patients with ESRD.

Direct characterization of solute transport in unsaturated porous media using fast X-ray synchrotron microtomography.

Solute transport in unsaturated porous materials is a complex process, which exhibits some distinct features differentiating it from transport under saturated conditions. These features emerge mostly due to the different transport time scales at different regions of the flow network, which can be classified into flowing and stagnant regions, predominantly controlled by advection and diffusion, respectively. Under unsaturated conditions, the solute breakthrough curves show early arrivals and very long tails, and this type of transport is usually referred to as non-Fickian. This study directly characterizes transport through an unsaturated porous medium in three spatial dimensions at the resolution of 3.25 µm and the time resolution of 6 s. Using advanced high-speed, high-spatial resolution, synchrotron-based X-ray computed microtomography (sCT) we obtained detailed information on solute transport through a glass bead packing at different saturations. A large experimental dataset (>50 TB) was produced, while imaging the evolution of the solute concentration with time at any given point within the field of view. We show that the fluids' topology has a critical signature on the non-Fickian transport, which yet needs to be included in the Darcy-scale solute transport models. The three-dimensional (3D) results show that the fully mixing assumption at the pore scale is not valid, and even after injection of several pore volumes the concentration field at the pore scale is not uniform. Additionally, results demonstrate that dispersivity is changing with saturation, being twofold larger at the saturation of 0.52 compared to that at the fully saturated domain.

Does High-Intensity Exercise Cause Acute Liver Injury in Patients with Fontan Circulation? A Prospective Pilot Study.

The Fontan procedure results in chronic hepatic congestion and Fontan-associated liver disease (FALD) characterized by progressive liver fibrosis and cirrhosis. Exercise is recommended in this population, but may accelerate the progression of FALD from abrupt elevations in central venous pressure. The aim of this study was to assess if acute liver injury occurs after high-intensity exercise in patients with Fontan physiology. Ten patients were enrolled. Nine had normal systolic ventricular function and one had an ejection fraction < 40%. During cardiopulmonary exercise testing, patients had near-infrared spectroscopy (NIRS) to measure oxygen saturation of multiple organs, including the liver, and underwent pre- and post-exercise testing with liver elastography, laboratory markers, and cytokines to assess liver injury. The hepatic and renal NIRS showed a statistically significant decrease in oxygenation during exercise, and the hepatic NIRS had the slowest recovery compared to renal, cerebral, and peripheral muscle NIRS. A clinically significant increase in shear wave velocity occurred after exercise testing only in the one patient with systolic dysfunction. There was a statistically significant, albeit trivial, increase in ALT and GGT after exercise. Fibrogenic cytokines traditionally associated with FALD did not increase significantly in our cohort; however, pro-inflammatory cytokines that predispose to fibrogenesis did significantly rise during exercise. Although patients with Fontan circulation demonstrated a significant reduction in hepatic tissue oxygenation based on NIRS saturations during exercise, there was no clinical evidence of acute increase in liver congestion or acute liver injury following high-intensity exercise.

Data processing methods and data acquisition for samples larger than the field of view in parallel-beam tomography.

Parallel-beam tomography systems at synchrotron facilities have limited field of view (FOV) determined by the available beam size and detector system coverage. Scanning the full size of samples bigger than the FOV requires various data acquisition schemes such as grid scan, 360-degree scan with offset center-of-rotation (COR), helical scan, or combinations of these schemes. Though straightforward to implement, these scanning techniques have not often been used due to the lack of software and methods to process such types of data in an easy and automated fashion. The ease of use and automation is critical at synchrotron facilities where using visual inspection in data processing steps such as image stitching, COR determination, or helical data conversion is impractical due to the large size of datasets. Here, we provide methods and their implementations in a Python package, named Algotom, for not only processing such data types but also with the highest quality possible. The efficiency and ease of use of these tools can help to extend applications of parallel-beam tomography systems.

Clinical utilization of whole-body PET/MRI in childhood sarcoma.

Hybrid positron emission tomography (PET)/magnetic resonance imaging (MRI) has emerged as a useful tool that combines the superior tissue contrast of MRI with the targeted functional imaging of PET. In the assessment of sarcomas in children, PET/MRI has the potential to serve as a single point of service, allowing superior anatomical imaging and evaluation of metabolic uptake during one imaging session. In this pictorial essay, we review our preliminary experience with PET/MRI in the evaluation of pediatric sarcoma. The limitations and contraindications of PET/MRI are also discussed.

Adequacy and Accuracy of Core Biopsy in Children: A Radiologic/Pathologic Correlation Study.

Core biopsy (CB) is increasingly popular for assessing solid lesions in children. To date, pediatric literature is limited regarding factors contributing to diagnostically inadequate or inaccurate CB. Therefore, we retrospectively examined radiologic/pathologic factors associated with adequacy/accuracy of CB in pediatric patients. A search of the surgical pathology database for CB between January 2007 and December 2014 yielded 134 CB from 99 patients. Age, sex, anatomic site of lesion, CB diagnosis, and final diagnosis were acquired from the electronic medical record. Image guidance modality, lesion size, and CB sampling device were obtained from radiology records. CB hematoxylin and eosin slides were reviewed for fragmentation, percentage of fibrosis, and percentage of necrosis. Overall, CB length was measured using cellSens software and a DP71 camera. Groups were compared using 2-sided homoscedastic Student's t tests; 87.3% (117/134) CB were diagnostic; final diagnosis was available for 105 cases, with a concordance rate of 80.0% (84/105). Image guidance modality, lesion site (extremity vs nonextremity), and CB needle gauge did not significantly differ between diagnostic versus nondiagnostic CB or concordant versus discordant CB. Diagnostic CB had less necrosis and fibrosis than did nondiagnostic CBs (6.8% vs 29.7%, P = .0002 and 10.3% vs 29.1%, P = .0006). Nondiagnostic and discordant CB were more likely to be from bony lesions than soft tissue ( P = .01 and P = .0248). CB is valuable for diagnosing solid lesions in children, with good overall diagnostic rates regardless of lesion size, location, or imaging modality used for biopsy. Nondiagnostic and discordant CB were more often obtained from bony lesions; sampling via open biopsy may be more useful in that setting. Nondiagnostic and discordant CB have more necrosis and fibrosis, suggesting that on-site evaluation of CB tissue viability-for example, by touch imprint or fine needle aspiration-may be useful in further enhancing CB utility.

Control of Metal-Organic Framework Crystallization by Metastable Intermediate Pre-equilibrium Species.

There is an increasing amount of interest in metal-organic frameworks (MOFs) for a variety of applications, from gas sensing and separations to electronics and catalysis. However, the mechanisms by which they crystallize remain poorly understood. Herein, an important new insight into MOF formation is reported. It is shown that, prior to network assembly, crystallization intermediates in the canonical ZIF-8 system exist in a dynamic pre-equilibrium, which depends on the reactant concentrations and the progress of reaction. Concentration can, therefore, be used as a synthetic handle to directly control particle size, with potential implications for industrial scale-up and gas sorption applications. These findings enable the rationalization of apparent contradictions between previous studies of ZIF-8 and opens up new opportunities for the control of crystallization in network solids more generally.

Superior techniques for eliminating ring artifacts in X-ray micro-tomography.

Synchrotron-based X-ray micro-tomography systems often suffer severe ring artifacts in reconstructed images. In sinograms the artifacts appear as straight lines or stripe artifacts. These artifacts are caused by the irregular response of a detecting system giving rise to a variety of observed types of stripes: full stripes, partial stripes, fluctuating stripes, and unresponsive stripes. The use of pre-processing techniques such as distortion correction or phase retrieval blurs and enlarges these stripes. It is impossible for a single approach to remove all types of stripe artifacts. Here, we propose three techniques for tackling all of them. The proposed techniques are easy to implement; do not generate extra stripe artifacts and void-center artifacts; and give superior quality on challenging data sets and in comparison with other techniques. Implementations in Python and a challenging data set are available for download.

Almost a spider: a 305-million-year-old fossil arachnid and spider origins.

Spiders are an important animal group, with a long history. Details of their origins remain limited, with little knowledge of their stem group, and no insights into the sequence of character acquisition during spider evolution. We describe a new fossil arachnid, Idmonarachne brasierigen. et sp. nov. from the Late Carboniferous (Stephanian,ca 305-299 Ma) of Montceau-les-Mines, France. It is three-dimensionally preserved within a siderite concretion, allowing both laboratory- and synchrotron-based phase-contrast computed tomography reconstruction. The latter is a first for siderite-hosted fossils and has allowed us to investigate fine anatomical details. Although distinctly spider-like in habitus, this remarkable fossil lacks a key diagnostic character of Araneae: spinnerets on the underside of the opisthosoma. It also lacks a flagelliform telson found in the recently recognized, spider-related, Devonian-Permian Uraraneida. Cladistic analysis resolves our new fossil as sister group to the spiders: the spider stem-group comprises the uraraneids and I. brasieri While we are unable to demonstrate the presence of spigots in this fossil, the recovered phylogeny suggests the earliest character to evolve on the spider stem-group is the secretion of silk. This would have been followed by the loss of a flagelliform telson, and then the ability to spin silk using spinnerets. This last innovation defines the true spiders, significantly post-dates the origins of silk, and may be a key to the group's success. The Montceau-les-Mines locality has previously yielded a mesothele spider (with spinnerets). Evidently, Late Palaeozoic spiders lived alongside Palaeozoic arachnid grades which approached the spider condition, but did not express the full suite of crown-group autapomorphies.

Pediatric Gastrojejunostomy Tube Replacement: Effects of Communication on the Need for After-Hours Procedures.

OBJECTIVES: The aim of the study was to determine whether embedding into the radiology report a patient-specific plan in the event of gastrojejunostomy (GJ) tube dysfunction reduces the need for after-hours utilization of pediatric interventional radiology resources for the replacement of GJ tubes. MATERIALS AND METHODS: This is a Health Insurance Portability and Accountability Act compliant, institutional review board-approved retrospective repeated cross-sectional study of patients requiring after-hours (5 PM-7 AM) or weekend (Saturday and Sunday) GJ tube replacement at a dedicated children's hospital, before and after the inclusion of a patient-specific plan in the radiology report as part of the electronic medical record. RESULTS: During a 6-month period before the inclusion of a patient-specific plan, there were 242 total GJ tube changes performed by the pediatric interventional radiology service under image guidance. Twenty-six (10.7%) of these procedures were performed outside of standard operating hours at the request of the emergency department (ED) (6/26), inpatient service (8/26), or patient/caregiver (12/26). Of the 8 inpatients, 3 were admitted from the ED for the sole purpose of tube replacement. Data were again collected for 6 months following inclusion of a patient-specific plan during the same seasonal period of the following year. During this period, 240 total image-guided changes were performed. Fifteen (6.2%) were performed outside of standard operating hours at the request of the ED (2/15), inpatient service (4/15), or patient/caregiver (9/15). No patients were admitted for GJ tube replacement procedures following implementation of the enhanced reporting policy. These data indicate a trend toward reduced after-hours resource utilization for GJ tube replacement requests by the ED (23.1%-13.3%), inpatient service (30.8%-26.7%), and all patients (14.7%-11%). Fewer after-hours GJ tube changes reduced cost by proportionately reducing hourly compensation for interventional radiology nurses and technicians. CONCLUSIONS: Our single-center data suggest that the inclusion of patient-specific recommendations at the end of each radiology GJ tube procedure note, generated in collaboration with the feeding service or primary medical provider, reduces off-hour resource utilization in patients who could otherwise have their tubes replaced during standard operating hours with image guidance. Avoidance of tube-related admissions is likely the greatest source of cost savings, followed by lower radiology technical support costs. Cost savings related to improved ED workflow and reduced patient/family anxiety are difficult to quantify, but likely significant. Future studies should be designed to quantify these savings and to assess the effect of this intervention on patient/caregiver satisfaction.

A rare case of cystic ganglionosis in a child with associated imaging findings.

Ganglia are benign soft tissue masses that are found adjacent to joints and tendons. They can be multifocal but they are rarely more numerous than a few around any given joint. "Cystic ganglionosis" has been used to describe a condition in which multifocal and extensive ganglia are present. We present a rare case of cystic ganglionosis in a Caucasian girl with clinical symptoms detected at 6 months of age. To the authors' knowledge, only a single other case report of cystic ganglionosis is documented in the English medical literature. The ganglia in this case are more extensive, manifested at an earlier age and caused erosions of multiple bones, a rarely observed complication of ganglia. Additionally, radiograph, MR and sonographic images collected over 9 years time allows for a detailed description of the imaging characteristics of this case of cystic ganglionosis, and offers unique insight into the natural history of this diagnosis. Extensive ganglia in multiple locations in a young child should alert clinicians to the possibility of cystic ganglionosis. Disease progression may lead to deleterious effects on bone warranting the use of maintenance imaging and possibly surgical resection of symptomatic lesions.

I12: the Joint Engineering, Environment and Processing (JEEP) beamline at Diamond Light Source.

I12 is the Joint Engineering, Environmental and Processing (JEEP) beamline, constructed during Phase II of the Diamond Light Source. I12 is located on a short (5 m) straight section of the Diamond storage ring and uses a 4.2 T superconducting wiggler to provide polychromatic and monochromatic X-rays in the energy range 50-150 keV. The beam energy enables good penetration through large or dense samples, combined with a large beam size (1 mrad horizontally × 0.3 mrad vertically). The beam characteristics permit the study of materials and processes inside environmental chambers without unacceptable attenuation of the beam and without the need to use sample sizes which are atypically small for the process under study. X-ray techniques available to users are radiography, tomography, energy-dispersive diffraction, monochromatic and white-beam two-dimensional diffraction/scattering and small-angle X-ray scattering. Since commencing operations in November 2009, I12 has established a broad user community in materials science and processing, chemical processing, biomedical engineering, civil engineering, environmental science, palaeontology and physics.

Radial lens distortion correction with sub-pixel accuracy for X-ray micro-tomography.

Distortion correction or camera calibration for an imaging system which is highly configurable and requires frequent disassembly for maintenance or replacement of parts needs a speedy method for recalibration. Here we present direct techniques for calculating distortion parameters of a non-linear model based on the correct determination of the center of distortion. These techniques are fast, very easy to implement, and accurate at sub-pixel level. The implementation at the X-ray tomography system of the I12 beamline, Diamond Light Source, which strictly requires sub-pixel accuracy, shows excellent performance in the calibration image and in the reconstructed images.

Virtual and Peer Reviews of Grant Applications at the Agency for Healthcare Research and Quality.

OBJECTIVES: This study documents the first six unplanned virtual review (VR) sessions conducted during the 2012 hurricane season at the Agency for Healthcare Research and Quality and their effects on review outcomes. It also compares these VR sessions with five face-to-face (FF) sessions. METHODS: In the first part of this study, six VR sessions are analyzed in terms of feasibility, reproducibility, and reviewers' responses to a questionnaire about VR. In the second part, the VR sessions are compared with five other FF meetings in terms of costs and duration per discussed application. RESULTS: Despite their technical novelty, all of the VR sessions have been successfully conducted to the satisfaction of reviewers and agency organizers. Special emphasis panel reviewers are more receptive to the new technology than study section reviewers: 75% versus 42%, respectively (P<0.05). Although the duration per discussed application is comparable to FF, the cost per reviewer is much lower for VR sessions than FF sessions. CONCLUSIONS: VR has successfully been used in six review sessions with a maximum of 34 discussed applications per session, special emphasis panel reviewers are more receptive to VR than SS reviewers, VR is a duplicable and low-cost method of review, and practitioners and scientists are urged to serve as reviewers because doing so may assist them in receiving funding.

Reliable method for calculating the center of rotation in parallel-beam tomography.

High-throughput processing of parallel-beam X-ray tomography at synchrotron facilities is lacking a reliable and robust method to determine the center of rotation in an automated fashion, i.e. without the need for a human scorer. Well-known techniques based on center of mass calculation, image registration, or reconstruction evaluation work well under favourable conditions but they fail in cases where samples are larger than field of view, when the projections show low signal-to-noise, or when optical defects dominate the contrast. Here we propose an alternative technique which is based on the Fourier analysis of the sinogram. Our technique shows excellent performance particularly on challenging data.

Pediatric abdominal and pelvic trauma: safety and efficacy of arterial embolization.

PURPOSE: Although transcatheter embolization is a well established technique to treat adults in the trauma setting, evidence is lacking in the pediatric population. This study assesses the safety and efficacy of arterial embolization for blunt abdominal and pelvic trauma in the pediatric population. MATERIALS AND METHODS: A retrospective review of abdominal and pelvic angiograms in 97 pediatric patients with blunt trauma was conducted over an 11-year period. Abdominal angiography and embolization was performed for ongoing hepatic, renal, splenic, or nonvisceral retroperitoneal injury. Pelvic angiography was performed in the setting of pelvic fracture with ongoing pelvic hemorrhage. Complications and clinical success rates of these procedures were assessed. RESULTS: Of the 97 pediatric patients who underwent angiography for acute abdominal or pelvic trauma, 54 (56%) required embolization involving 62 separate sites. Injury severity score greater than 15 was present in 94% of patients. Targets of embolization included the pelvis (n = 39), liver (n = 8), kidney (n = 7), spleen (n = 6), and retroperitoneum (n = 2). Effective hemorrhage control was achieved in 47 patients (87%). Overall mortality rate was 22% (12 of 54), with most deaths related to traumatic brain injury. Five complications occurred in four patients (7%), including three major complications (hepatic abscess, bile leak, and urinary incontinence). CONCLUSIONS: Angiography and embolization is relatively safe and potentially effective in the setting of abdominal and pelvic trauma in the pediatric population. Angiography with embolization should be considered in the treatment algorithm for this patient population.

Assessment of infant gonadal dose irradiated from urine-contaminated diapers during diuretic renal scintigraphy.

OBJECTIVE: To estimate the gonadal doses irradiated from urine- contaminated diapers during diuretic renal scintigraphy. METHODS: Images of 31 patients (18 males and 13 females) with urine-contaminated diapers during 99m Tc-MAG3 renal scintigraphy were analyzed. The count rate of the diapers was converted into a time-activity curve based on the calibrated factor of the gamma camera system. The cumulative activity was determined from the area under the curve. By incorporating dose per unit cumulative activity pre-calculated from Monte Carlo simulation with 0-year phantom, the gonadal dose irradiated from diaper was calculated. To assess the degree of this additionally introduced dose from diapers, the calculated gonadal dose was compared to the internal gonadal dose from injected radiotracer activity. RESULTS: The cumulative activities irradiated from urine-contaminated diapers were 1.12 E04 ±â€…1.29E04 MBq.s in male infants, which was nearly half of the 1.94 E04 ±â€…1.80E04 MBq.s ( P  = 0.15) in female infants. However, the absorbed doses for testes in male infants were 7.37E-01 ±â€…8.50E-01 mGy, which was approximately 10 times the 6.38E-02 ±â€…5.94E-02 mGy for ovaries in female infants ( P  < 0.01). The diaper-introduced dose for testes and ovaries was 91.7% and 3.9% of the gonadal doses from the injected activity in patients with normal renal function, and 99.0% and 4.3% of those in patients with abnormal renal function. CONCLUSION: Urine-contaminated diapers introduced additional radiation doses to infant patients during 99m Tc-MAG3 renal scintigraphy. The gonadal doses were of significance in male infants who had nearly double the absorbed dose for the testes.

Frequency of external iliac artery branch injury in blunt trauma: improved detection with selective external iliac angiography.

PURPOSE: To assess the utility of selective external iliac artery (EIA) angiography and the frequency of injury to branches of the EIA in cases of blunt pelvic trauma. MATERIALS AND METHODS: A retrospective review of pelvic angiograms in 66 patients with blunt pelvic trauma was conducted over a 12-month period. Pelvic and femur fracture patterns were correlated to the presence of EIA injury. Pelvic arteriography was compared versus selective EIA angiography for the detection of arterial injury. RESULTS: Fifty-four of 66 patients (82%) exhibited pelvic arterial injury or elicited enough suspicion for injury to warrant embolization. Internal iliac artery embolization was performed in 50 of 66 (76%). EIA branch injury was identified in 11 of 66 patients (17%), and 10 were successfully embolized. EIA branch vessel injury was identified more frequently when there was ipsilateral intertrochanteric fracture (P = .07) or ipsilateral ilium fracture (P = .07). The sensitivity of nonselective pelvic angiography in the detection of EIA branch vessel injury was 45%. CONCLUSIONS: EIA branch injury occurs in a substantial fraction of patients with blunt pelvic trauma who undergo pelvic angiography. Selective EIA angiography should be considered in all patients undergoing pelvic angiography in this situation.