High-resolution Assessment Research Articles

Distribution of Paclitaxel Particles on the Vascular Wall After Drug-Coated Balloon Treatment - Electronic High-Resolution Angioscopy Assessment.

Distribution of Paclitaxel Particles on the Vascular Wall After Drug-Coated Balloon Treatment - Electronic High-Resolution Angioscopy Assessment.

A GIS-based high spatial resolution assessment of large-scale PV generation potential in China

The achievement of temperature control target requires a low carbon transition of global energy structure. While China is actively promoting the implementation of large-scale PV generation technology, there is still a lack of scientific knowledge of the generation potential in China. To address this deficiency, this study builds a GIS-based model with 600 land conversion factors incorporated to accurately estimate the large-scale PV power generation potential in China. The results show a potential installed capacity of 1.41 × 105 GW, corresponding to an annual power generation of 1.38874 × 1014 kWh or 21.4 times national electricity consumption in China 2016. If this potential were fully realized as a replacement for current fossil fuel-based power generation in China 2030, a reduction in China’s carbon intensity of 63–68% compared to 2005 would result, which is sufficient to meet China’s CO2 emission reduction commitment. On a provincial level, while generation potential in Northwest and Inner Mongolia together account for 86% of the total, China's eight economically developed coastal provinces only account for 1%. To achieve a maximum large-scale PV scenario in China 2030, the capacity of inter-regional transmission grids from Northwest region and Inner Mongolia to the regions with insufficient potential should reach an approximate 300 GW. Our study could provide decision-makers with the precise information on large-scale PV power generation map of China, and optimizing low carbon strategies and inter-regional power transmission for achieving sustainable development.

EP-1754 High-resolution assessment of dose calculations in small MV photon beams on and off central axis

EP-1754 High-resolution assessment of dose calculations in small MV photon beams on and off central axis

Radiofrequency ablation lesion assessment using optical coherence tomography - a proof-of-concept study.

Radiofrequency catheter ablation (RFA) is an effective treatment for atrial fibrillation. However, ablation lesions are usually only assessed functionally. The immediate effect of RFA on the tissue is not directly visualized. Optical coherence tomography (OCT) is an imaging technique that uses light to capture high-resolution images with histology-like quality. Therefore, it might be used for high-precision imaging of ablation lesions. Radiofrequency ablation lesions (n = 25) were produced on the freshly excised left and right ventricular porcine endocardium. A Thermocool ST SF NAV ablation catheter (Biosense Webster Inc) and an EP-Shuttle ablation generator (Stockert GmbH) were used to produce ablation lesions with powers from 10 to 40 W (energies ranging from 100 Ws to 900 Ws). After ablation, the tissue was imaged with a swept source OCT system (at a wavelength of 1300 nm). Subsequently, the ablation lesions underwent the histological analysis. The ablation lesions could be visualized by OCT in all 17 samples with ablation powers ≥20 W, meanwhile, no lesion could be observed in the other eight samples with lower power (10 W). Lesion depths and lesion radiuses, as assessed by OCT, correlated well with those observed on the subsequent histological analysis (Spearman's r = 0.94, P < 0.001 and r = 0.84, P < 0.001). In addition, successful three-dimensional reconstructions of ablation lesions were performed. OCT can provide a visual high-resolution assessment of ablation lesions.

Low-cost materials yield high resolution assessment of anatomic knowledge in surgical residents

IntroductionKnowledge of anatomy is essential for surgeons. We sought to determine whether it is possible to effectively assess and differentiate the anatomic knowledge of general surgery residents, using pieces of fabric and yarn. MethodsPostgraduate years 2, 3, and 4 general surgery residents were assessed during a simulation-based assessment known as the Surgical X-Games. Residents were allowed 3 minutes to assemble the anatomic structures of the right upper quadrant region and 2 minutes to create the right lower quadrant of the abdomen, using colored felt and yarn. One point (each) was given for naming and placing the structures in the correct position. A checklist was used to assess trainees with a maximum combined score of 150 points. ResultsA total of 34 residents (postgraduate year 2 = 16, postgraduate year 3 = 8, postgraduate year 4 = 10) participated in the 2017 fall Surgical X-Games and 31 residents (postgraduate year 2 = 13, postgraduate year 3 = 9, postgraduate year 4 = 9) participated in the spring Surgical X-Games. Total scores increased respective to the level of clinical training in both the fall Surgical X-Games (postgraduate year 2 = 77, postgraduate year 3 = 84, postgraduate year 4 = 93, P = .04) and the spring Surgical X-Games (postgraduate year 2 = 94, postgraduate year 3 = 101, postgraduate year 4 = 109). We observed significant improvement in the right upper quadrant, right lower quadrant, and total scores from the fall to the spring postgraduate year (P < .001). ConclusionSurgical residents showed an increase in mean anatomical scores from postgraduate years 2 to postgraduate years 3 to postgraduate years 4, using low-fidelity models. This inexpensive, 5-minute test based on a simple checklist may offer surgical educators insight in to residents’ anatomic knowledge and potential readiness for clinical rotations.

Applying grey water footprint assessment to achieve environmental sustainability within a nation under intensive agriculture: a high-resolution assessment for common agrochemicals and crops

Achieving safer environment under intensive agriculture highly depends on input resource management. This research is the first grey water footprint (WF) assessment in which the field-scale heterogeneities in input data are considered to provide new insights for achieving sustainable environment under dense farming. For a 10-year period over 2005–2015, grey WF accounting and impact assessment was carried out, together with sensitivity and uncertainty analysis, for a wide range of agrochemicals commonly applied to the agricultural soils in Iran. Given results were then applied to provide new applicable solutions for reducing the overall pollutant loaded to freshwater bodies from diffuse sources. The 10-year average of the given results showed that with an overall load of 77.1 thousand t year−1, N was the most critical substance among various agrochemicals, especially within the irrigated lands, where are the origin of 83.1% of loaded N to freshwater bodies. Cereals, both irrigated and rainfed, always had the largest contribution in the overall pollutants loaded to water bodies. At the national sale, 48.2 billion m3 year−1 water is annually required to take up the N pollution loads, which is 26.8% less than actual runoff within the country. While the national-scale water pollutant level (WPL) was 0.7, the high-resolution assessment indicated the existence of local polluted area with WPL > 1 in 42.8% of the country, 96% of which located within the arid and semi-arid regions. In these areas, the river’s waste assimilation capacity has been overused by the factors of 1–32.8. Based on the quantitative impact assessment, the overall N-related grey WFs may be reduced by 47% if grey WFs are lowered down to the benchmark levels set at the 25th percentile of crop production, by 9.1% if crops’ yield is improved by 10%, and by 27.8% if N-application rates are reduced to the optimal rate. In addition, regional prioritizing of cropping pattern based on their grey WFs may result in an expressive reduction in WPL due to the large diversity in grey WFs among crops and regions. Based on the results, it could be concluded that, with a 10–16.1% uncertainties, a high-resolution local-scale grey WF assessment is a promising way to achieve safer agricultural environment in a dense-farming country.

Novel methods for high-resolution assessment of cardiac action potential repolarization

The profile of the action potential (AP) of cardiomyocytes contributes to the modality of ventricular repolarization of the heart. Experimentally, the examination of the AP in isolated cardiomyocytes provides information on their electrical properties, adaptations to physiological and pathological conditions, and putative ionic mechanisms involved in the process. Currently, there are no available platforms for automated assessment of AP properties and standard methodologies restrict the examination of the AP repolarization to discrete, user-defined ranges, neglecting significant intervals of the electrical recovery. This study proposes two automatic methods to assess AP profile throughout the entire repolarization phase. One method is based on AP data inversion and direct extraction of patterns describing beat-to-beat dynamics. The second method is based on evolutive singular value decomposition (ESVD), which identifies common patterns in a series of consecutive APs. The two methodologies were employed to analyze electrical signals collected from cardiomyocytes obtained from healthy mice and animals with diabetes, a condition associated with alterations of AP properties in cardiac cells. Our methodologies revealed that the duration of the early repolarization phase of the AP tended to become progressively longer during a stimulation train, whereas the late repolarization progressively shortened. Although this behavior was comparable in the two groups of cells, alterations in AP dynamics occurred at distinct repolarization levels, a feature highlighted by the ESVD approach. In conclusion, the proposed methodologies allow detailed, automatic analysis of the AP repolarization and identification of critical alterations occurring in the electrical behavior of myocytes under pathological conditions.

3D grating-based X-ray phase-contrast computed tomography for high-resolution quantitative assessment of cartilage: An experimental feasibility study with 3T MRI, 7T MRI and biomechanical correlation.

ObjectiveAim of this study was, to demonstrate the feasibility of high-resolution grating-based X-ray phase-contrast computed tomography (PCCT) for quantitative assessment of cartilage.Materials and methodsIn an experimental setup, 12 osteochondral samples were harvested from n = 6 bovine knees (n = 2 each). From each knee, one cartilage sample was degraded using 2.5% Trypsin. In addition to PCCT and biomechanical cartilage stiffness measurements, 3T and 7T MRI was performed including MSME SE T2 and ME GE T2* mapping sequences for relaxationtime measurements. Paired t-tests and receiver operating characteristics (ROC) curves were used for statistical analyses.ResultsPCCT provided high-resolution images for improved morphological cartilage evaluation as compared to 3T and 7T MRI. Quantitative analyses revealed significant differences between the superficial and the deep cartilage layer for T2 mapping as well as for PCCT (P<0.05). No significant difference was detected for PCCT between healthy and degraded samples (P>0.05). MRI and stiffness measurements showed significant differences between healthy and degraded osteochondral samples. Accuracy in the prediction of cartilage degradation was excellent for MRI and biomechanical analyses.ConclusionIn conclusion, high-resolution grating-based X-ray PCCT cartilage imaging is feasible. In addition to MRI and biomechanical analyses it provides complementary, water content independent, information for improved morphological and quantitative characterization of articular cartilage ultrastructure.

Enabling combined access to electricity and clean cooking with PV-microgrids: new evidences from a high-resolution model of cooking loads

Electric cooking (or e-cooking) based on renewable sources and highly-efficient cooking devices could represent a sustainable and reliable option to achieve the universal access to clean cooking facilities by 2030. Still, the techno-economic feasibility of e-cooking has never been evaluated through (i) a high-resolution assessment of the electric and cooking load profiles, coupled with (ii) a least-cost energy system optimisation for the related electricity supply. Hence, the present study aims at accurately investigating the techno-economic potential of a fully-renewable solar micro-grid, ensuring an integrated access to electricity and clean cooking, based on two representative case studies in Tanzania, namely: (i) a residential case study, and (ii) a community-service case study. Bottom-up stochastic load profiles are generated for the two contexts by expanding the existing LoadProGen model with a novel complementary algorithm for the computation of high-resolution cooking loads. The cost-optimised results prove the cost-competitiveness of e-cooking, especially for the community-service case, where it would require only an additional 17% capital investment due to the pre-existence of other energy-intensive activities. Moreover, the range of Levelised Cost for Cooking a Meal (LCCM) obtained for e-cooking considering the different scenarios lies within 0.16 ÷ 0.70 USD/meal, a range that is comparable with that of all other cooking options – including firewood –, and even more cost-competitive than LPG.

High resolution satellite observations give new view of UK air quality

New state‐of‐the‐art satellite measurements of tropospheric column NO2 from the TROPOMI instrument on‐board Sentinel‐5 Precursor (S5P), launched in October 2017, allow for an unprecedented high resolution (sub‐10km) assessment of UK air quality (AQ) from space. We present the first results from TROPOMI and compare them with its predecessor, the Ozone Monitoring Instrument (OMI), to quantify previously unresolved UK pollution hotspots (e.g. Bristol, Southampton and Liverpool). The TROPOMI tropospheric column NO2 data represents a powerful new tool to quantify UK AQ, evaluate atmospheric composition models and potentially derive new emission inventories from space.

Brain iron content in systemic iron overload: A beta-thalassemia quantitative MRI study.

Multisystem iron poisoning is a major concern for long-term beta-thalassemia management. Quantitative MRI-based techniques routinely show iron overload in heart, liver, endocrine glands and kidneys. However, data on the brain are conflicting and monitoring of brain iron content is still matter of debate. This 3T-MRI study applied a well validated high-resolution whole-brain quantitative MRI assessment of iron content on 47 transfusion-dependent (mean-age: 36.9 ± 10.3 years, 63% females), 23 non-transfusion dependent (mean-age: 29.2 ± 11.7 years, 56% females) and 57 healthy controls (mean-age: 33.9 ± 10.8 years, 65% females). Clinical data, Wechsler Adult Intelligence Scale scores and treatment regimens were recorded. Beside whole-brain R2* analyses, regional R2*-values were extracted in putamen, globus pallidum, caudate nucleus, thalamus and red nucleus; hippocampal volumes were also determined. Regional analyses yielded no significant differences between patients and controls, except in those treated with deferiprone that showed lower R2*-values (p<0.05). Whole-brain analyses of R2*-maps revealed strong age-R2* correlations (r2=0.51) in both groups and clusters of significantly increased R2*-values in beta-thalassemia patients in the hippocampal formations and around the Luschka foramina; transfusion treatment was associated with additional R2* increase in dorsal thalami. Hippocampal formation R2*-values did not correlate with hippocampal volume; hippocampal volume did not differ between patients and controls. All regions with increased R2*-values shared a strict anatomical contiguity with choroid plexuses suggesting a blooming effect as the likely cause of R2* increase, in agreement with the available histopathologic literature evidence. According to our MRI findings and the available histopathologic literature evidence, concerns about neural tissue iron overload in beta-thalassemia appear to be unjustified.

Revisiting the Reliability of the Endoscopy and Sedation-Assisted High-Resolution Esophageal Motility Assessment.

BackgroundEsophageal high-resolution manometry (HRM) is performed for evaluation of dysphagia or the pre-operative evaluation before esophageal surgery. The esophageal manometry parameters, interpreted as per the Chicago classification (CC), are meant to be acquired in an awake state. At times, the patient intolerance or inability to traverse the manometry catheter across the esophagogastric junction (EGJ) renders incomplete esophageal motility evaluation; hence, sedation or endoscopy assistance is required. There have been concerns raised regarding the use of sedation and resultant alteration of the manometry parameters. The aims were to study the effects of intravenous sedation on esophageal motility parameters and analyze its impact on outcomes of patients with dysphagia who are intolerant to awake manometry procedure.MethodsThe study population comprised patients who had sedation or the endoscopy assistance for the HRM. The indication for HRM, necessity for the sedation, manometry findings, barium esophagogram results, procedural timings and patient outcomes were reviewed. The diagnostic impact of the 10% correction in integrated relaxation pressure (IRP) was also studied.ResultsThere were 14 patients from 179 awake manometry procedures that required the sedation or the endoscopy assistance. The mean age was 60.7 years and there was equal gender distribution. Dysphagia (n = 9) remained the predominant indication for the HRM, followed by the pre-operative evaluation for the esophageal surgery (n = 5). In eight patients, awake manometry failed due to the coiling of the catheter above the EGJ and six patients were intolerant to awake catheter insertion technique. Six patients were diagnosed with achalasia and two with EGJ obstruction. The correction of the possible 10% inflation of the IRP did not alter the final diagnosis in majority except one patient with the EGJ obstruction. The findings of the barium esophagogram corroborated the manometry diagnosis.ConclusionEsophageal HRM should be done in awake state as much as possible. Sedation may be a feasible option as against aborting the further workup in patients who fail with current techniques involving awake catheter insertion. However, one needs to be mindful of sedation effects on manometry parameters and interpret results carefully.

Sleep Deprivation Selectively Upregulates an Amygdala-Hypothalamic Circuit Involved in Food Reward.

Sleep loss is associated with increased obesity risk, as demonstrated by correlations between sleep duration and change in body mass index or body fat percentage. Whereas previous studies linked this weight gain to disturbed endocrine parameters after sleep deprivation or restriction, neuroimaging studies revealed upregulated neural processing of food rewards after sleep loss in reward-processing areas such as the anterior cingulate cortex, ventral striatum, and insula. To address this ongoing debate between hormonal versus hedonic factors underlying sleep-loss-associated weight gain, we rigorously tested the association between sleep deprivation and food cue processing using high-resolution fMRI and assessment of hormones. After taking blood samples from 32 lean, healthy, human male participants, they underwent fMRI while performing a neuroeconomic, value-based decision-making task with snack food and trinket rewards following a full night of habitual sleep and a night of sleep deprivation in a repeated-measures crossover design. We found that des-acyl ghrelin concentrations were increased after sleep deprivation compared with habitual sleep. Despite similar hunger ratings due to fasting in both conditions, participants were willing to spend more money on food items only after sleep deprivation. Furthermore, fMRI data paralleled this behavioral finding, revealing a food-reward-specific upregulation of hypothalamic valuation signals and amygdala-hypothalamic coupling after a single night of sleep deprivation. Behavioral and fMRI results were not significantly correlated with changes in acyl, des-acyl, or total ghrelin concentrations. Our results suggest that increased food valuation after sleep loss might be due to hedonic rather than hormonal mechanisms.SIGNIFICANCE STATEMENT Epidemiological studies suggest an association between overweight and reduced nocturnal sleep, but the relative contributions of hedonic and hormonal factors to overeating after sleep loss are a matter of ongoing controversy. Here, we tested the association between sleep deprivation and food cue processing in a repeated-measures crossover design using fMRI. We found that willingness to pay increased for food items only after sleep deprivation. fMRI data paralleled this behavioral finding, revealing a food-reward-specific upregulation of hypothalamic valuation signals and amygdala-hypothalamic coupling after a single night of sleep deprivation. However, there was no evidence for hormonal modulations of behavioral or fMRI findings. Our results suggest that increased food valuation after sleep loss is due to hedonic rather than hormonal mechanisms.

High-resolution coastal hazard assessment along the French Riviera from co-seismic tsunamis generated in the Ligurian fault system

The French Riviera is a densely populated and touristic coast. It is also one of the most seismically active areas of the Western Mediterranean. This is evidenced by the Mw 6.7–6.9, 1887 earthquake and tsunami, that was triggered nearshore, rupturing the easternmost 40 km of the 80-km-long Ligurian fault system, which runs parallel to and offshore of the Riviera. Here, coastal hazard from co-seismic tsunamis is assessed along the French and part of the Italian Riviera by simulating three Ligurian earthquake scenarios: (1) the 1887 event offshore Genoa, Italy; (2) a similar event transposed to the westernmost 40-km segment of the fault, offshore Nice, France; and (3) the rupture of the entire 80-km fault, which constitutes an extreme case scenario for the region. Simulations of tsunami propagation and coastal impact are performed by one-way coupling with the Boussinesq model FUNWAVE-TVD, in a series of nested grids, using new high-resolution bathymetric and topographic data. Results obtained in 10-m coastal grids provide the highest resolution predictions to date for this section of the French Riviera of co-seismic tsunami coastal hazard, in terms of inundation, runup, and current velocity. In general, the most impacted areas are bays (near Cap d’Antibes and Cap Ferrat), due to wave buildup and shoaling within semi-enclosed shallow areas, enhanced by possible resonances. In contrast to earlier work, which was based on coarser resolution grids, the area of Nice harbor is found to be rather well sheltered. It should be noted that uniform fault slip was used in the ruptures and runup estimates could locally be enhanced in case of more complex ruptures, such as segmented and heterogeneous ruptures.

High-Resolution Infrared Thermal Imaging of the Esophagus During Atrial Fibrillation Ablation as a Predictor of Endoscopically Detected Thermal Lesions: Results From the HEAT-AF Study.

Endoscopically detected thermal esophageal lesions (EDEL) after ablation of atrial fibrillation may be precursors of atrioesophageal fistula and esophageal luminal temperature monitoring has previously failed to decrease thermal damage. Sixty-three patients undergoing their first pulmonary vein isolation using radiofrequency point-by-point catheter ablation were prospectively included in the HEAT-AF study (High-Resolution Esophageal Assessment of Esophageal Temperature During Atrial Fibrillation Ablation) and esophageal temperatures were continuously monitored using a novel infrared thermography system (IRTS). Peak esophageal temperature (Tpeak) was correlated to postablation endoscopy results characterizing patients as EDEL positive or negative. Twelve patients had EDEL (19%). Comparing EDEL positive to negative patients, Tpeak was significantly higher (56.3±4.6°C versus 45.7±5.5°C, P<0.0001). Logistic regression analysis demonstrated Tpeak was a statistically significant predictor ( P=0.0008) of EDEL and yielded an odds ratio of 1.52; 95% CI, (1.24-2.05). Receiver operator curve analysis demonstrated Tpeak as a highly accurate binary classifier with an area under the curve of 93%. For the first time esophageal temperature monitoring using a high resolution, high-fidelity IRTS allowed accurate prediction of postablation EDEL suggesting that Tpeak alone is an excellent binary classifier of patients at risk of EDEL. The logistic regression model and associated receiver operator curve will aid in the selection of optimal temperature thresholds in future prospective studies.

Tumor Retention of Enzyme-Responsive Pt(II) Drug-Loaded Nanoparticles Imaged by Nanoscale Secondary Ion Mass Spectrometry and Fluorescence Microscopy.

In nanomedicine, determining the spatial distribution of particles and drugs, together and apart, at high resolution within tissues, remains a major challenge because each must have a different label or detectable feature that can be observed with high sensitivity and resolution. We prepared nanoparticles capable of enzyme-directed assembly of particle therapeutics (EDAPT), containing an analogue of the Pt(II)-containing drug oxaliplatin, an 15N-labeled monomer in the hydrophobic block of the backbone of the polymer, the near-infrared dye Cy5.5, and a peptide that is a substrate for tumor metalloproteinases in the hydrophilic block. When these particles reach an environment rich in tumor associated proteases, the hydrophilic peptide substrate is cleaved, causing the particles to accumulate through a morphology transition, locking them in the tumor extracellular matrix. To evaluate the distribution of drug and EDAPT carrier in vivo, the localization of the isotopically labeled polymer backbone was compared to that of Pt by nanoscale secondary ion mass spectrometry (NanoSIMS). The correlation of NanoSIMS with super-resolution fluorescence microscopy revealed the release of the drug from the nanocarrier and colocalization with cellular DNA within tumor tissue. The results confirmed the dependence of particle accumulation and Pt(II) drug delivery on the presence of a Matrix Metalloproteinase (MMP) substrate and demonstrated antitumor activity. We conclude that these techniques are powerful for the elucidation of the localization of cargo and carrier, and enable a high-resolution assessment of their performance following in vivo delivery.

Estimating Fine-Scale Temporal and Spatial Characteristics of SO2 Exposures Using U.S. EPA's Air Pollutants Exposure (APEX) Model

The U.S. EPA Air Pollutants Exposure Model (APEX) is a stochastic model simulating inhalation exposure using fine-scale population demographics, human activity and physiology, time series of ambient chemical concentrations, and parameterizations of chemical infiltration into microenvironments. For a recent high-resolution population-based exposure assessment of three U.S. urban areas (Tulsa, OK; Indianapolis, IN; Fall River, MA), we used APEX to estimate the percent of the study population experiencing 5-minute SO2 exposures at or above selected benchmark levels (100&amp;#8211;400 ppb, 100-ppb increments) and the resultant lung-function decrements. We generated complete time series of 5-minute ambient SO2 concentrations at thousands of receptors in each study area, combining modeled hourly concentrations with continuous 5-minute ambient measurements for 2011&amp;#8211;2013, then adjusted to just meet the current national ambient air quality standard. We developed new model input data and algorithms as a function of sex and age to support the high resolution of this assessment, including data on demographics, commuting patterns, and asthma prevalence at the level of U.S. Census blocks, and algorithms to estimate short-term breathing rates and energy expenditure. Results showed notable differences in SO2 exposure by location, with fewer elevated exposures and health risks estimated in Tulsa, OK relative to the other study areas. An important factor in these results is the lower numbers of people estimated to live or work in areas of higher SO2 concentrations in the Tulsa scenario relative to the other scenarios. These results indicate the importance of the accuracy and spatiotemporal resolution of the air concentration and population data in estimating population exposures and health risks to inform policy decisions.

Is sonoelastography a helpful method of evaluation to diagnose Sjögren's syndrome?

A new sonoelastography technique - virtual touch tissue quantification of acoustic radiation force impulses (ARFI) - offers a promising method for measuring tissue rigidity. The aim of this study was to assess the usefulness of ARFI for diagnosing Sjögren's syndrome (SS). This transversal prospective study included 41 patients with SS according to American-European Consensus Group (AECG) criteria, and a control group without symptoms. All subjects underwent ARFI high-resolution ultrasound assessment of the parotid glands (PG) and submandibular glands (SMG). In patients with SS, parotid gland shear wave velocity (SWV) was 2.08m/s±0.55, significantly higher than in control subjects (1.2m/s±0.17) (P=0.0001); submandibular gland SWV was higher in SS patients (2.12m/s±0.44) than control subjects (1.56m/s±0.16) (P=0.001). Acoustic radiation force impulses sonoelastography can assist diagnosis of SS, and is a non-invasive and fast method of detecting pathological changes to the parotid and submandibular glands.

In Vivo Second Harmonic Generation Microscopy as a Novel Assessment of Nerve Damage

Grant support received from: 2017 AFSH AFSH Basic Science Grant Royalty: Smith and Nephew (Hausman) Receipt of Intellectual Property Rights: Checkpoint Surgical (Hausman) Consulting Fee: Checkpoint Surgical (Hausman) Speaker's Bureau: Skeletal Dynamics, TriMed (Hausman) Ownership Interest: Checkpoint Surgical, NDI Medical (Hausman) We hypothesize second harmonic-generation (SHG) microscopy can be utilized as an in vivo, real-time imaging modality of peripheral nerve structural damage due to a stretch injury. Furthermore, we seek to validate these findings by using intraoperative nerve stimulation as a functional assessment of nerve damage. Following IACUC approval, Sprague-Dawley rats (N=5) were anesthetized and micro dissection was performed to separate median nerves from surrounding tissue. A biphasic handheld surgical nerve stimulator was used to probe median nerves before and after intervention to assess nerve function by monitoring for a twitch of the paw. 1cm of the right median nerve was placed in a custom-made stretch applicator and a 20% strain was applied to the nerve for 5 minutes, simulating a high-strain injury (HS). Left median nerves served as a sham control (SC), being treated exactly the same with the exception of applying a strain. Subjects were then brought to the microscopy core facility where they were imaged in vivo using a multiphoton microscope. In vivo SHG images of both HS and SC nerves demonstrated the ability to visualize epineurial collagen fibers. All (5 of 5) HS nerves at day 0 demonstrated undulating wavy fibers with general disorganization and large amounts of fiber crossing (Figure 46-1B). Conversely, 5 of 5 SC nerves at day 0 demonstrated intact, parallel, linearly organized collagen structure with no evidence of crossing fibers (Figure 46-1A). At 84 days postinjury, 4/5 HS nerves demonstrated complete recovery validated by linearly organized, parallel collagen fibers (Figure 46-1D). Nerve stimulation data corroborated with patterns of collagen structure observed via SHG microscopy. All nerves (HS and SC) required the same baseline stimulation value of 0.025 μC to produce a twitch of the paw. Following injury, HS nerves required a mean increase of 0.135 μC to induce a twitch (P = .0053) (Figure 46-2A) while SC nerves required no increase in stimulation. Comparing day 0 postintervention values with day 84 values, 4 of 5 HS nerves demonstrated complete recovery of function with a mean recovery of –0.12 μC (P = .0283) (Figure 46-2B). No SC nerves required an increase in stimulation at post-sham day 0 and day 84 conditions. •In vivo SHG microscopy provides high-resolution real-time visual assessment of nerve damage.•Intraoperative nerve stimulation is a novel and accurate functional assessment of nerve damage in animal models.•Epineurial collagen organization may be a reliable marker of nerve health and function.Figure 46-2AB(A) Day 0 intraoperative nerve stimulation data indicates no change in pre- and postsham values in SC nerves. A statistically significant increase in stimulation was observed between pre- and poststretch values in HS nerves. (B) A comparison of intraoperative nerve stimulation values at postintervention day 0 and at day 84 indicates a statistically significant recovery of stimulation values in HS nerves. No change was observed in SC nerves.View Large Image Figure ViewerDownload Hi-res image Download (PPT)View Large Image Figure ViewerDownload Hi-res image Download (PPT) This research was supported by a Basic Science Grant from the American Foundation for Surgery of the Hand.

High Resolution Assessment of Spatio-Temporal Changes in O2 Concentration in Root-Pathogen Interaction.

Fusarium wilt, caused by the fungus Fusarium oxysporum f. sp. lycopersici (Fol), is one of the most destructive soil-borne diseases of tomatoes. Infection takes place on the roots and the process starts with contact between the fungus and the roots hairs. To date, no detailed studies are available on metabolic activity in the early stages of the Fol and tomato root interaction. Spatial and temporal patterns of oxygen consumption could provide new insights into the dynamics of early colonization. Here, we combined planar optodes and spatial analysis to assess how tomato roots influence the metabolic activity and growth patterns of Fol. The results shows that the fungal metabolism, measured as oxygen consumption, increases within a few hours after the inoculation. Statistical analysis revealed that the fungus tends to growth toward the root, whereas, when the root is not present, the single elements of the fungus move with a Brownian motion (random). The combination of planar optodes and spatial analysis is a powerful new tool for assessing temporal and spatial dynamics in the early stages of root-pathogen interaction.