Radiomics-based decision support tool assists radiologists in small lung nodule classification and improves lung cancer early diagnosis

BACKGROUND

Methods to improve stratification of small (≤15 mm) lung nodules are needed. We aimed to develop a radiomics model to assist lung cancer diagnosis.

METHODS

Patients were retrospectively identified using health records from January 2007 to December 2018. The external test set was obtained from the national LIBRA study and a prospective Lung Cancer Screening programme. Radiomics features were extracted from multi-region CT segmentations using TexLab2.0. LASSO regression generated the 5-feature small nodule radiomics-predictive-vector (SN-RPV). K-means clustering was used to split patients into risk groups according to SN-RPV. Model performance was compared to 6 thoracic radiologists. SN-RPV and radiologist risk groups were combined to generate "Safety-Net" and "Early Diagnosis" decision-support tools.

RESULTS

In total, 810 patients with 990 nodules were included. The AUC for malignancy prediction was 0.85 (95% CI: 0.82-0.87), 0.78 (95% CI: 0.70-0.85) and 0.78 (95% CI: 0.59-0.92) for the training, test and external test datasets, respectively. The test set accuracy was 73% (95% CI: 65-81%) and resulted in 66.67% improvements in potentially missed [8/12] or delayed [6/9] cancers, compared to the radiologist with performance closest to the mean of six readers.

CONCLUSIONS

SN-RPV may provide net-benefit in terms of earlier cancer diagnosis.

The Relationship Between Cardiac Troponin in People Hospitalised for Exacerbation of COPD and Major Adverse Cardiac Events (MACE) and COPD Readmissions

Background

No single biomarker currently risk stratifies chronic obstructive pulmonary disease (COPD) patients at the time of an exacerbation, though previous studies have suggested that patients with elevated troponin at exacerbation have worse outcomes. This study evaluated the relationship between peak cardiac troponin and subsequent major adverse cardiac events (MACE) including all-cause mortality and COPD hospital readmission, among patients admitted with COPD exacerbation.

Methods

Data from five cross-regional hospitals in England were analysed using the National Institute of Health Research Health Informatics Collaborative (NIHR-HIC) acute coronary syndrome database (2008-2017). People hospitalised with a COPD exacerbation were included, and peak troponin levels were standardised relative to the 99th percentile (upper limit of normal). We used Cox Proportional Hazard models adjusting for age, sex, laboratory results and clinical risk factors, and implemented logarithmic transformation (base-10 logarithm). The primary outcome was risk of MACE within 90 days from peak troponin measurement. Secondary outcome was risk of COPD readmission within 90 days from peak troponin measurement.

Results

There were 2487 patients included. Of these, 377 (15.2%) patients had a MACE event and 203 (8.2%) were readmitted within 90 days from peak troponin measurement. A total of 1107 (44.5%) patients had an elevated troponin level. Of 1107 patients with elevated troponin at exacerbation, 256 (22.8%) had a MACE event and 101 (9.0%) a COPD readmission within 90 days from peak troponin measurement. Patients with troponin above the upper limit of normal had a higher risk of MACE (adjusted HR 2.20, 95% CI 1.75-2.77) and COPD hospital readmission (adjusted HR 1.37, 95% CI 1.02-1.83) when compared with patients without elevated troponin.

Conclusion

An elevated troponin level at the time of COPD exacerbation may be a useful tool for predicting MACE in COPD patients. The relationship between degree of troponin elevation and risk of future events is complex and requires further investigation.

Non-contrast CT synthesis using patch-based cycle-consistent generative adversarial network (Cycle-GAN) for radiomics and deep learning in the era of COVID-19

Handcrafted and deep learning (DL) radiomics are popular techniques used to develop computed tomography (CT) imaging-based artificial intelligence models for COVID-19 research. However, contrast heterogeneity from real-world datasets may impair model performance. Contrast-homogenous datasets present a potential solution. We developed a 3D patch-based cycle-consistent generative adversarial network (cycle-GAN) to synthesize non-contrast images from contrast CTs, as a data homogenization tool. We used a multi-centre dataset of 2078 scans from 1,650 patients with COVID-19. Few studies have previously evaluated GAN-generated images with handcrafted radiomics, DL and human assessment tasks. We evaluated the performance of our cycle-GAN with these three approaches. In a modified Turing-test, human experts identified synthetic vs acquired images, with a false positive rate of 67% and Fleiss' Kappa 0.06, attesting to the photorealism of the synthetic images. However, on testing performance of machine learning classifiers with radiomic features, performance decreased with use of synthetic images. Marked percentage difference was noted in feature values between pre- and post-GAN non-contrast images. With DL classification, deterioration in performance was observed with synthetic images. Our results show that whilst GANs can produce images sufficient to pass human assessment, caution is advised before GAN-synthesized images are used in medical imaging applications.

Defining the road map to a UK national lung cancer screening programme

Lung cancer screening with low-dose CT was recommended by the UK National Screening Committee (UKNSC) in September, 2022, on the basis of data from trials showing a reduction in lung cancer mortality. These trials provide sufficient evidence to show clinical efficacy, but further work is needed to prove deliverability in preparation for a national roll-out of the first major targeted screening programme. The UK has been world leading in addressing logistical issues with lung cancer screening through clinical trials, implementation pilots, and the National Health Service (NHS) England Targeted Lung Health Check Programme. In this Policy Review, we describe the consensus reached by a multiprofessional group of experts in lung cancer screening on the key requirements and priorities for effective implementation of a programme. We summarise the output from a round-table meeting of clinicians, behavioural scientists, stakeholder organisations, and representatives from NHS England, the UKNSC, and the four UK nations. This Policy Review will be an important tool in the ongoing expansion and evolution of an already successful programme, and provides a summary of UK expert opinion for consideration by those organising and delivering lung cancer screenings in other countries.

A radiomics-based decision support tool improves lung cancer diagnosis in combination with the Herder score in large lung nodules

BACKGROUND

Large lung nodules (≥15 mm) have the highest risk of malignancy, and may exhibit important differences in phenotypic or clinical characteristics to their smaller counterparts. Existing risk models do not stratify large nodules well. We aimed to develop and validate an integrated segmentation and classification pipeline, incorporating deep-learning and traditional radiomics, to classify large lung nodules according to cancer risk.

METHODS

502 patients from five U.K. centres were recruited to the large-nodule arm of the retrospective LIBRA study between July 2020 and April 2022. 838 CT scans were used for model development, split into training and test sets (70% and 30% respectively). An nnUNet model was trained to automate lung nodule segmentation. A radiomics signature was developed to classify nodules according to malignancy risk. Performance of the radiomics model, termed the large-nodule radiomics predictive vector (LN-RPV), was compared to three radiologists and the Brock and Herder scores.

FINDINGS

499 patients had technically evaluable scans (mean age 69 ± 11, 257 men, 242 women). In the test set of 252 scans, the nnUNet achieved a DICE score of 0.86, and the LN-RPV achieved an AUC of 0.83 (95% CI 0.77-0.88) for malignancy classification. Performance was higher than the median radiologist (AUC 0.75 [95% CI 0.70-0.81], DeLong p = 0.03). LN-RPV was robust to auto-segmentation (ICC 0.94). For baseline solid nodules in the test set (117 patients), LN-RPV had an AUC of 0.87 (95% CI 0.80-0.93) compared to 0.67 (95% CI 0.55-0.76, DeLong p = 0.002) for the Brock score and 0.83 (95% CI 0.75-0.90, DeLong p = 0.4) for the Herder score. In the international external test set (n = 151), LN-RPV maintained an AUC of 0.75 (95% CI 0.63-0.85). 18 out of 22 (82%) malignant nodules in the Herder 10-70% category in the test set were identified as high risk by the decision-support tool, and may have been referred for earlier intervention.

INTERPRETATION

The model accurately segments and classifies large lung nodules, and may improve upon existing clinical models.

FUNDING

This project represents independent research funded by: 1) Royal Marsden Partners Cancer Alliance, 2) the Royal Marsden Cancer Charity, 3) the National Institute for Health Research (NIHR) Biomedical Research Centre at the Royal Marsden NHS Foundation Trust and The Institute of Cancer Research, London, 4) the National Institute for Health Research (NIHR) Biomedical Research Centre at Imperial College London, 5) Cancer Research UK (C309/A31316).

A comparison of machine learning methods for predicting recurrence and death after curative-intent radiotherapy for non-small cell lung cancer: Development and validation of multivariable clinical prediction models

BACKGROUND

Surveillance is universally recommended for non-small cell lung cancer (NSCLC) patients treated with curative-intent radiotherapy. High-quality evidence to inform optimal surveillance strategies is lacking. Machine learning demonstrates promise in accurate outcome prediction for a variety of health conditions. The purpose of this study was to utilise readily available patient, tumour, and treatment data to develop, validate and externally test machine learning models for predicting recurrence, recurrence-free survival (RFS) and overall survival (OS) at 2 years from treatment.

METHODS

A retrospective, multicentre study of patients receiving curative-intent radiotherapy for NSCLC was undertaken. A total of 657 patients from 5 hospitals were eligible for inclusion. Data pre-processing derived 34 features for predictive modelling. Combinations of 8 feature reduction methods and 10 machine learning classification algorithms were compared, producing risk-stratification models for predicting recurrence, RFS and OS. Models were compared with 10-fold cross validation and an external test set and benchmarked against TNM-stage and performance status. Youden Index was derived from validation set ROC curves to distinguish high and low risk groups and Kaplan-Meier analyses performed.

FINDINGS

Median follow-up time was 852 days. Parameters were well matched across training-validation and external test sets: Mean age was 73 and 71 respectively, and recurrence, RFS and OS rates at 2 years were 43% vs 34%, 54% vs 47% and 54% vs 47% respectively. The respective validation and test set AUCs were as follows: 1) RFS: 0·682 (0·575-0·788) and 0·681 (0·597-0·766), 2) Recurrence: 0·687 (0·582-0·793) and 0·722 (0·635-0·81), and 3) OS: 0·759 (0·663-0·855) and 0·717 (0·634-0·8). Our models were superior to TNM stage and performance status in predicting recurrence and OS.

INTERPRETATION

This robust and ready to use machine learning method, validated and externally tested, sets the stage for future clinical trials entailing quantitative personalised risk-stratification and surveillance following curative-intent radiotherapy for NSCLC.

FUNDING

A full list of funding bodies that contributed to this study can be found in the Acknowledgements section.

Immune Checkpoint Inhibitor and Radiotherapy-Related Pneumonitis: An Informatics Approach to Determine Real-World Incidence, Severity, Management, and Resource Implications

Pneumonitis is a well-described, potentially life-threatening adverse effect of immune checkpoint inhibitors (ICI) and thoracic radiotherapy. It can require additional investigations, treatment, and interruption of cancer therapy. It is important for clinicians to have an awareness of its incidence and severity, however real-world data are lacking and do not always correlate with findings from clinical trials. Similarly, there is a dearth of information on cost impact of symptomatic pneumonitis. Informatics approaches are increasingly being applied to healthcare data for their ability to identify specific patient cohorts efficiently, at scale. We developed a Structured Query Language (SQL)-based informatics algorithm which we applied to CT report text to identify cases of ICI and radiotherapy pneumonitis between 1/1/2015 and 31/12/2020. Further data on severity, investigations, medical management were also acquired from the electronic health record. We identified 248 cases of pneumonitis attributable to ICI and/or radiotherapy, of which 139 were symptomatic with CTCAE severity grade 2 or more. The grade ≥2 ICI pneumonitis incidence in our cohort is 5.43%, greater than the all-grade 1.3–2.7% incidence reported in the literature. Time to onset of ICI pneumonitis was also longer in our cohort (mean 4.5 months, range 4 days-21 months), compared to the median 2.7 months (range 9 days−19.2 months) described in the literature. The estimated average healthcare cost of symptomatic pneumonitis is £3932.33 per patient. In this study we use an informatics approach to present new real-world data on the incidence, severity, management, and resource burden of ICI and radiotherapy pneumonitis. To our knowledge, this is the first study to look at real-world incidence and healthcare resource utilisation at the per-patient level in a UK cancer hospital. Improved management of pneumonitis may facilitate prompt continuation of cancer therapy, and improved outcomes for this not insubstantial cohort of patients.

Ingestion of A Common Plant's Leaves Leads to Acute Respiratory Arrest and Paralysis: A Case Report

Background

Nicotiana glauca is a plant known to cause acute toxicity upon ingestion or dermal exposure due to the nicotinic alkaloid, anabasine. Nicotinic alkaloids cause toxicity by acting as agonists on nicotinic-type acetylcholine receptors (nAChRs). Initial stimulation of these receptors leads to symptoms such as tachycardia, miosis, and tremors. The effects of high doses of nicotinic alkaloids are biphasic, and eventual persistent depolarization of nAChRs at the neuromuscular junction occurs. This causes apnea, paralysis, and cardiovascular collapse.

Case Report

In this report, we present a case of respiratory arrest due to nicotinic alkaloid poisoning from the ingestion of Nicotiana glauca. The diagnosis was suspected after the patient’s family gave a history of the patient ingesting a plant prior to arrival. They were able to also provide a physical sample of the plant.

Conclusion

The phone application, “Plant Snap”, determined the plant species and helped confirm the diagnosis. This case describes how modern technology and thorough history taking can combine to provide the best possible patient care.

Adalimumab in Juvenile Idiopathic Arthritis-Associated Uveitis: 5-Year Follow-up of the Bristol Participants of the SYCAMORE Trial

PURPOSE

To determine longer-term outcomes of participants enrolled from a single center in the SYCAMORE trial, a randomized placebo-controlled trial of adalimumab vs placebo in children with juvenile idiopathic arthritis-associated uveitis (JIA-U) uncontrolled on methotrexate.

DESIGN

Retrospective interventional case series.

METHODS

Medical records of all 28 SYCAMORE participants recruited at the Bristol Eye Hospital were reviewed at approximately 3-monthly intervals up to 5 years from the trial randomization date. Uveitis activity, treatment course, visual outcomes, ocular complications, and adverse events were recorded. Data are presented using summary statistics.

RESULTS

Following withdrawal of the investigational medicinal product (IMP), 25 of the 28 participants were started on adalimumab for active JIA-U. Of the 12 participants in the active treatment arm of the SYCAMORE study, 11 (92%) were restarted on adalimumab after withdrawal of the IMP for active JIA-U (median time to flare 188 days [range 42-413 days). Two participants stopped adalimumab for uncontrolled JIA-U. One participant had a reduction in vision to 0.3 owing to cataract. Mean visual acuity for the remaining 27 participants was -0.04 (right eye) and -0.05 (left eye).

CONCLUSIONS

Drug-induced remission of JIA-U did not persist when adalimumab was withdrawn after 1-2 years of treatment. Adalimumab was well tolerated and visual acuity outcomes were excellent.

Clocking Femtosecond Collisional Dynamics via Resonant X-Ray Spectroscopy

Electron-ion collisional dynamics is of fundamental importance in determining plasma transport properties, nonequilibrium plasma evolution, and electron damage in diffraction imaging applications using bright x-ray free-electron lasers (FELs). Here we describe the first experimental measurements of ultrafast electron impact collisional ionization dynamics using resonant core-hole spectroscopy in a solid-density magnesium plasma, created and diagnosed with the Linac Coherent Light Source x-ray FEL. By resonantly pumping the 1s→2p transition in highly charged ions within an optically thin plasma, we have measured how off-resonance charge states are populated via collisional processes on femtosecond time scales. We present a collisional cross section model that matches our results and demonstrates how the cross sections are enhanced by dense-plasma effects including continuum lowering. Nonlocal thermodynamic equilibrium collisional radiative simulations show excellent agreement with the experimental results and provide new insight on collisional ionization and three-body-recombination processes in the dense-plasma regime.

Potent inhibition of human organic cation transporter 2 (hOCT2) by β-carboline alkaloids

1. Beta-carbolines are indole alkaloids with a wide range of pharmacological and toxicological activities. Beta-carbolines are structurally related to the neurotoxin 1-methyl-4-phenylpyridinium (MPP+), a known substrate of organic cation transporters (OCTs). The goal of this study is to determine the interaction of β-carbolines with human OCT1, 2, and 3 (SLC22A1-3). 2. Dose-dependent inhibition studies were performed for five commercially available β-carbolines using a fluorescent substrate assay in HEK293 cells stably expressing hOCT1-3. The substrate potential was evaluated by uptake assays and the impact of active transport on cellular toxicity examined. 3. All tested β-carbolines potently inhibited hOCT2 with IC50 values in the sub- or low micromolar range. Harmaline is the most potent hOCT2 inhibitor (IC50 = 0.50 ± 0.08 μM). hOCT1 and hOCT3 are less sensitive to β-carboline inhibition. Harmaline, norharmanium, and 2,9-dimethyl-4,9-dihydro-3H-β-carbolinium accumulated 2- to 7-fold higher in cells expressing hOCT1-3. HEK293 cells expressing hOCT1-3 were 6.5- to 13-fold more sensitive to harmane and norharmanium toxicity. 4. Our data support a significant role of hOCT1-3 in tissue uptake and disposition of β-carbolines. Importantly, the potent inhibition of hOCT2 by β-carbolines also raises the concern of potential drug interactions between naturally occurring bioactive alkaloids and drugs eliminated by hOCT2.

Measurements of the K-Shell Opacity of a Solid-Density Magnesium Plasma Heated by an X-Ray Free-Electron Laser

We present measurements of the spectrally resolved x rays emitted from solid-density magnesium targets of varying sub-μm thicknesses isochorically heated by an x-ray laser. The data exhibit a largely thickness-independent source function, allowing the extraction of a measure of the opacity to K-shell x rays within well-defined regimes of electron density and temperature, extremely close to local thermodynamic equilibrium conditions. The deduced opacities at the peak of the Kα transitions of the ions are consistent with those predicted by detailed atomic-kinetics calculations.

Benchmark Experiment for Photoionized Plasma Emission from Accretion-Powered X-Ray Sources

The interpretation of x-ray spectra emerging from x-ray binaries and active galactic nuclei accreted plasmas relies on complex physical models for radiation generation and transport in photoionized plasmas. These models have not been sufficiently experimentally validated. We have developed a highly reproducible benchmark experiment to study spectrum formation from a photoionized silicon plasma in a regime comparable to astrophysical plasmas. Ionization predictions are higher than inferred from measured absorption spectra. Self-emission measured at adjustable column densities tests radiation transport effects, demonstrating that the resonant Auger destruction assumption used to interpret black hole accretion spectra is inaccurate.

Observation of Reverse Saturable Absorption of an X-ray Laser

A nonlinear absorber in which the excited state absorption is larger than the ground state can undergo a process called reverse saturable absorption. It is a well-known phenomenon in laser physics in the optical regime, but is more difficult to generate in the x-ray regime, where fast nonradiative core electron transitions typically dominate the population kinetics during light matter interactions. Here, we report the first observation of decreasing x-ray transmission in a solid target pumped by intense x-ray free electron laser pulses. The measurement has been made below the K-absorption edge of aluminum, and the x-ray intensity ranges are 10^{16} -10^{17}  W/cm^{2}. It has been confirmed by collisional radiative population kinetic calculations, underscoring the fast spectral modulation of the x-ray pulses and charge states relevant to the absorption and transmission of x-ray photons. The processes shown through detailed simulations are consistent with reverse saturable absorption, which would be the first observation of this phenomena in the x-ray regime. These light matter interactions provide a unique opportunity to investigate optical transport properties in the extreme state of matters, as well as affording the potential to regulate ultrafast x-ray free-electron laser pulses.

MET-EGFR dimerization in lung adenocarcinoma is dependent on EGFR mtations and altered by MET kinase inhibition

Advanced lung cancer has poor survival with few therapies. EGFR tyrosine kinase inhibitors (TKIs) have high response rates in patients with activating EGFR mutations, but acquired resistance is inevitable. Acquisition of the EGFR T790M mutation causes over 50% of resistance; MET amplification is also common. Preclinical data suggest synergy between MET and EGFR inhibitors. We hypothesized that EGFR-MET dimerization determines response to MET inhibition, depending on EGFR mutation status, independently of MET copy number. We tested this hypothesis by generating isogenic cell lines from NCI-H1975 cells, which co-express L858R and T790M EGFR mutations, namely H1975L858R/T790M (EGFR TKI resistant); H1975L858R (sensitized) and H1975WT (wild-type). We assessed cell proliferation in vitro and tumor growth/stroma formation in derived xenograft models in response to a MET TKI (SGX523) and correlated with EGFR-MET dimerization assessed by Förster Resonance Energy Transfer (FRET). SGX523 significantly reduced H1975L858R/T790M cell proliferation, xenograft tumor growth and decreased ERK phosphorylation. The same was not seen in H1975L858R or H1975WT cells. SGX523 only reduced stroma formation in H1975L858R. SGX523 reduced EGFR-MET dimerization in H1975L858R/T790M but induced dimer formation in H1975L858R with no effect in H1975WT. Our data suggests that MET inhibition by SGX523 and EGFR-MET heterodimerisation are determined by EGFR genotype. As tumor behaviour is modulated by this interaction, this could determine treatment efficacy.

Development and validation of a novel bioassay to determine glucocorticoid sensitivity

Background

Glucocorticoids (GCs) remain the first line treatment for almost all non-infectious inflammatory diseases, ranging from acute asthma to rheumatoid arthritis. However, across all conditions, patients have a variable response to GCs with approximately 30% being non-responders. This group of GC resistant patients is typically exposed to high-dose GCs and their side-effects before more appropriate immunotherapy is instituted. Hence, there is a pressing clinical need for a predictive biomarker of GC responsiveness. The availability of such a tool would also enable patient stratification for the conduct of smart clinical trials in GC resistance. Lymphocyte GC sensitivity has been shown to be closely associated with clinical GC sensitivity in a number of inflammatory diseases. However, the method for determining in vitro GC response is not standardized and requires the use of specialist equipment, including a radioisotope to quantify cellular proliferation, making it challenging to translate into clinical practice.

Results

Here we describe the optimization and validation of a novel non-radioactive in vitro bioassay based on measuring cellular proliferation by incorporation of bromodeoxyuridine (BrdU), termed the BrdU incorporation in lymphocyte steroid sensitivity assay (BLISS). In comparison to the current gold standard lymphocyte GC sensitivity assay in 101 healthy control samples, BLISS has an area under receiver operating characteristic of 0.82 and a sensitivity of 83% for correctly identifying GC resistant subjects.

Conclusions

The performance of the novel BLISS bioassay makes it a strong candidate biomarker for clinical application. It now requires validation in a prospective patient cohort.

Electronic supplementary material

The online version of this article (doi:10.1186/s40364-016-0079-y) contains supplementary material, which is available to authorized users.

An anti-TNF-α antibody mimetic to treat ocular inflammation

Infliximab is an antibody that neutralizes TNF-α and is used principally by systemic administration to treat many inflammatory disorders. We prepared the antibody mimetic Fab-PEG-Fab (FpF_infliximab) for direct intravitreal injection to assess whether such formulations have biological activity and potential utility for ocular use. FpF_infliximab was designed to address side effects caused by antibody degradation and the presence of the Fc region. Surface plasmon resonance analysis indicated that infliximab and FpF_infliximab maintained binding affinity for both human and murine recombinant TNF-α. No Fc mediated RPE cellular uptake was observed for FpF_infliximab. Both Infliximab and FpF_infliximab suppressed ocular inflammation by reducing the number of CD45+ infiltrate cells in the EAU mice after a single intravitreal injection at the onset of peak disease. These results offer an opportunity to develop and formulate for ocular use, FpF molecules designed for single and potentially multiple targets using bi-specific FpFs.

Consensus on the Diagnosis and Management of Nonparaneoplastic Autoimmune Retinopathy Using a Modified Delphi Approach

PURPOSE

To develop diagnostic criteria for nonparaneoplastic autoimmune retinopathy (AIR) through expert panel consensus and to examine treatment patterns among clinical experts.

DESIGN

Modified Delphi process.

METHODS

A survey of uveitis specialists in the American Uveitis Society, a face-to-face meeting (AIR Workshop) held at the National Eye Institute, and 2 iterations of expert panel surveys were used in a modified Delphi process. The expert panel consisted of 17 experts, including uveitis specialists and researchers with expertise in antiretinal antibody detection. Supermajority consensus was used and defined as 75% of experts in agreement.

RESULTS

There was unanimous agreement among experts regarding the categorization of autoimmune retinopathies as nonparaneoplastic and paraneoplastic, including cancer-associated retinopathy and melanoma-associated retinopathy. Diagnostic criteria and tests essential to the diagnosis of nonparaneoplastic AIR and multiple supportive criteria reached consensus. For treatment, experts agreed that corticosteroids and conventional immunosuppressives should be used (prescribed) as first- or second-line treatments, though a consensus agreed that biologics and intravenous immunoglobulin were considered appropriate in the treatment of nonparaneoplastic AIR patients regardless of the stage of disease. Experts agreed that more evidence is needed to treat nonparaneoplastic AIR patients with long-term immunomodulatory therapy and that there is enough equipoise to justify randomized, placebo-controlled trials to determine if nonparaneoplastic AIR patients should be treated with long-term immunomodulatory therapy. Regarding antiretinal antibody detection, consensus agreed that a standardized assay system is needed to detect serum antiretinal antibodies. Consensus agreed that an ideal assay should have a 2-tier design and that Western blot and immunohistochemistry should be the methods used to identify antiretinal antibodies.

CONCLUSIONS

Consensus was achieved using a modified Delphi process to develop diagnostic criteria for nonparaneoplastic AIR. There is enough equipoise to justify randomized, placebo-controlled trials to determine whether patients with nonparaneoplastic AIR should be treated with long-term immunomodulatory therapy. Efforts to develop a standardized 2-tier assay system for the detection of antiretinal antibodies have been initiated as a result of this study.

Evaluation of Objective Vitritis Grading Method Using Optical Coherence Tomography: Influence of Phakic Status and Previous Vitrectomy

PURPOSE

To evaluate a proposed method for objective measurement of vitreous inflammation using a spectral-domain optical coherence tomography (SD OCT) device in a large cohort of uveitis eyes, including pseudophakic eyes and vitrectomized eyes.

DESIGN

Retrospective, observational cohort study.

METHODS

One hundred five uveitis eyes (105 patients) with different vitreous haze score grades according to standardized protocols and corresponding SD OCT images (Cirrus HD-OCT; Carl Zeiss Meditec, Dublin, California, USA) were included. Clinical data recorded included phakic status, previous vitreoretinal surgery, and anterior chamber (AC) cells and flare. SD OCT images were analyzed using custom software that provided absolute measurements of vitreous (VIT) and retinal pigment epithelium (RPE) signal intensities, which were compared to generate a relative optical density ratio with arbitrary units (VIT/RPE-relative intensity) and compared to VHS.

RESULTS

VIT/RPE-relative intensity showed a significant positive correlation with vitreous haze score (r = 0.535, P < .001) that remained significant after adjusting for factors governing media clarity, such as AC cells, AC flare, and phakic status (R(2)-adjusted = 0.424, P < .001). Significant differences were also observed between the different vitreous haze score groups (P < .001). Preliminary observation did not observe differences in VIT/RPE-relative intensity values between phakic and pseudophakic eyes (0.3522 vs 0.3577, P = .48) and between nonvitrectomized and vitrectomized eyes (0.3540 vs 0.3580, P = .52), overall and respectively for each vitreous haze score subgroup.

CONCLUSIONS

VIT/RPE-relative intensity values provide objective measurements of vitreous inflammation employing an SD OCT device. Phakic status and previous vitrectomy surgery do not appear to influence these values, although these preliminary findings need validation in future studies.

A simple method for in vivo labelling of infiltrating leukocytes in the mouse retina using indocyanine green dye

We have developed a method to label and image myeloid cells infiltrating the mouse retina and choroid in vivo, using a single depot injection of indocyanine green dye (ICG). This was demonstrated using the following ocular models of inflammation and angiogenesis: endotoxin-induced uveitis, experimental autoimmune uveoretinitis and laser-induced choroidal neovascularization model. A near-infrared scanning ophthalmoscope was used for in vivo imaging of the eye, and flow cytometry was used on blood and spleen to assess the number and phenotype of labelled cells. ICG was administered 72 h before the induction of inflammation to ensure clearance from the systemic circulation. We found that in vivo intravenous administration failed to label any leukocytes, whereas depot injection, either intraperitoneal or subcutaneous, was successful in labelling leukocytes infiltrating into the retina. Progression of inflammation in the retina could be traced over a period of 14 days following a single depot injection of ICG. Additionally, bright-field microscopy, spectrophotometry and flow cytometric analysis suggest that the predominant population of cells stained by ICG are circulating myeloid cells. The translation of this approach into clinical practice would enable visualization of immune cells in situ. This will not only provide a greater understanding of pathogenesis, monitoring and assessment of therapy in many human ocular diseases but might also open the ability to image immunity live for neurodegenerative disorders, cardiovascular disease and systemic immune-mediated disorders.

Summary: We show here that peripheral leukocytes can be labelled with ICG in vivo and then directly imaged as they invade the retina after inflammatory stimuli.

Shot-to-shot intensity and wavefront stability of high-harmonic generation

We report on the shot-to-shot stability of intensity and spatial phase of high-harmonic generation (HHG). The intensity stability is measured for each high-harmonic (HH) order with a spectrometer. Additionally, the spatial phase is measured with an XUV wavefront sensor for a single HH order measured in a single shot, which according to our knowledge was not reported before with a Hartmann wavefront sensor. Furthermore, we compare the single-shot measurement of the spatial phase with time-integrated measurements and we show that the XUV wavefront sensor is a useful tool to simultaneously optimize the spatial phase and intensity of HHG within the available HHG parameter range used in this study.

The Matter in Extreme Conditions instrument at the Linac Coherent Light Source

The LCLS beam provides revolutionary capabilities for studying the transient behavior of matter in extreme conditions. The particular strength of the Matter in Extreme Conditions instrument is that it combines the unique LCLS beam with high-power optical laser beams, and a suite of dedicated diagnostics tailored for this field of science. In this paper an overview of the beamline, the capabilities of the instrumentation, and selected highlights of experiments and commissioning results are presented.

Investigation of femtosecond collisional ionization rates in a solid-density aluminium plasma

The rate at which atoms and ions within a plasma are further ionized by collisions with the free electrons is a fundamental parameter that dictates the dynamics of plasma systems at intermediate and high densities. While collision rates are well known experimentally in a few dilute systems, similar measurements for nonideal plasmas at densities approaching or exceeding those of solids remain elusive. Here we describe a spectroscopic method to study collision rates in solid-density aluminium plasmas created and diagnosed using the Linac Coherent light Source free-electron X-ray laser, tuned to specific interaction pathways around the absorption edges of ionic charge states. We estimate the rate of collisional ionization in solid-density aluminium plasmas at temperatures ~30 eV to be several times higher than that predicted by standard semiempirical models.

Saturable absorption of an x-ray free-electron-laser heated solid-density aluminum plasma

High-intensity x-ray pulses from an x-ray free-electron laser are used to heat and probe a solid-density aluminum sample. The photon-energy-dependent transmission of the heating beam is studied through the use of a photodiode. Saturable absorption is observed, with the resulting transmission differing significantly from the cold case, in good agreement with atomic-kinetics simulations.

Multicenter study of intravitreal dexamethasone implant in noninfectious uveitis: indications, outcomes, and reinjection frequency

PURPOSE

To identify clinical outcomes and treatment patterns of intravitreal dexamethasone implant (Ozurdex; Allergan, Inc) in noninfectious uveitis in the clinical setting.

DESIGN

Multicenter retrospective cohort study.

METHODS

Eighty-two eyes (63 patients) receiving 142 implant injections over 35 months were included. Treatment indication, uveitis diagnosis, visual acuity, intraocular pressure, vitreous haze score, central retinal thickness by optical coherence tomography, phakic status, number of injections, time to reinjection, systemic treatments, and complications data were collected. Time to visual acuity and vitreous haze score improvement as per the Standardization of Uveitis Nomenclature guidelines were also determined.

RESULTS

The probability of visual acuity improvement (≥0.3 logarithm of the minimal angle of resolution units improvement) was 39% at 1 month, 49% at 3 months, 52% at 6 months, and 58% at 12 months. Eyes with baseline vitritis (vitreous haze score ≥+0.5, n = 45) had a probability of vitreous haze score improvement (2-step decrease or change from +0.5 to 0) at 2 weeks of 41%, at 1 month 63%, at 3 months 73%, at 6 months 79%, and at 12 months 88%. In eyes that completed 12-month follow-up (n = 54), 40.7% underwent 2 injections (mean time to second injection of 6.6 ± 1.9 months) and 11.2% required ≥3 injections (mean time to third injection of 11 ± 1.5 months).

CONCLUSIONS

Dexamethasone implant use in uveitis provides favorable visual acuity and vitreous haze score outcomes but requires repeated injections, an important consideration when choosing intraocular treatment as a route to controlling uveitis.

Pharmacotherapy for uveitis: current management and emerging therapy

Uveitis, a group of conditions characterized by intraocular inflammation, is a major cause of sight loss in the working population. Most uveitis seen in Western countries is noninfectious and appears to be autoimmune or autoinflammatory in nature, requiring treatment with immunosuppressive and/or anti-inflammatory drugs. In this educational review, we outline the ideal characteristics of drugs for uveitis and review the data to support the use of current and emerging therapies in this context. It is crucial that we continue to develop new therapies for use in uveitis that aim to suppress disease activity, prevent accumulation of damage, and preserve visual function for patients with the minimum possible side effects.

Autoimmune and autoinflammatory mechanisms in uveitis

The eye, as currently viewed, is neither immunologically ignorant nor sequestered from the systemic environment. The eye utilises distinct immunoregulatory mechanisms to preserve tissue and cellular function in the face of immune-mediated insult; clinically, inflammation following such an insult is termed uveitis. The intra-ocular inflammation in uveitis may be clinically obvious as a result of infection (e.g. toxoplasma, herpes), but in the main infection, if any, remains covert. We now recognise that healthy tissues including the retina have regulatory mechanisms imparted by control of myeloid cells through receptors (e.g. CD200R) and soluble inhibitory factors (e.g. alpha-MSH), regulation of the blood retinal barrier, and active immune surveillance. Once homoeostasis has been disrupted and inflammation ensues, the mechanisms to regulate inflammation, including T cell apoptosis, generation of T_reg cells, and myeloid cell suppression in situ, are less successful. Why inflammation becomes persistent remains unknown, but extrapolating from animal models, possibilities include differential trafficking of T cells from the retina, residency of CD8⁺ T cells, and alterations of myeloid cell phenotype and function. Translating lessons learned from animal models to humans has been helped by system biology approaches and informatics, which suggest that diseased animals and people share similar changes in T cell phenotypes and monocyte function to date. Together the data infer a possible cryptic infectious drive in uveitis that unlocks and drives persistent autoimmune responses, or promotes further innate immune responses. Thus there may be many mechanisms in common with those observed in autoinflammatory disorders.

Objective measurement of vitreous inflammation using optical coherence tomography

PURPOSE

To obtain measurements of vitreous signal intensity from optical coherence tomography (OCT) image sets in patients with uveitis, with the aim of developing an objective, quantitative marker of inflammatory activity in patients with this disease.

DESIGN

Retrospective, observational case-control series.

PARTICIPANTS

Thirty patients (30 eyes) with vitreous haze secondary to intermediate, posterior, or panuveitis; 12 patients (12 eyes) with uveitis but without evidence of vitreous haze; and 18 patients (18 eyes) without intraocular inflammation or vitreoretinal disease.

METHODS

Clinical and demographic characteristics were recorded, including visual acuity (VA), diagnosis, and anatomic type of uveitis. In each eye, the anterior chamber (AC) was graded for cellular activity and flare according to standardized protocols. The presence and severity of vitreous haze were classified according to the National Eye Institute system. Spectral-domain OCT images were analyzed using custom software. This software provided an "absolute" measurement of vitreous signal intensity, which was then compared with that of the retinal pigment epithelium (RPE), generating an optical density ratio with arbitrary units ("VIT/RPE-Relative Intensity").

MAIN OUTCOME MEASURES

Correlation between clinical vitreous haze scores and OCT-derived measurements of vitreous signal intensity.

RESULTS

The VIT/RPE-Relative Intensity was significantly higher in uveitic eyes with known vitreous haze (0.150) than in uveitic eyes without haze or in healthy controls (0.0767, P = 0.0001). The VIT/RPE-Relative Intensity showed a significant, positive correlation with clinical vitreous haze scores (r = 0.566, P = 0.0001). Other ocular characteristics significantly associated with VIT/RPE-Relative Intensity included VA (r = 0.573, P = 0.0001), AC cells (r = 0.613, P = 0.0001), and AC flare (r = 0.385, P = 0.003). Measurement of VIT/RPE-Relative Intensity showed a good degree of intergrader reproducibility (95% limits of agreement, -0.019 to 0.016).

CONCLUSIONS

These results provide preliminary evidence that OCT-derived measurements of vitreous signal intensity may be useful as an outcome measure in patients with uveitis. If validated in future studies, such measures may serve as an objective, quantitative disease activity end point, with the potential to improve the "signal:noise" ratio of clinical trials in this area, thus enabling smaller studies for the same power. The incorporation of automated vitreous analysis in commercial OCT systems may, in turn, facilitate monitoring and re-treatment of patients with uveitis in clinical practice.

Physical evidence for recombination of chloroplast dna in hybrid progeny of Chlamydomonas eugametos and C. moewusii

Differences in the restriction endonuclease fragmentation patterns of chloroplast DNA (cpDNA) from C. eugametos and C. moewusii have been used to study the inheritance of these DNAs in interspecific hybrids. Analysis of the cpDNAs from ten randomly selected F1 hybrids, in each case revealed cpDNA to be recombinant for AvaI and BstEII restriction sites, although fragments characteristic of C. eugametos, the mt+ parent, were typically found in excess of those for C. moewusii, the mt- parent. In backcrosses between an F 1 mt+ hybrid and C. moewusii mt-, seven randomly selected B1 hybrids showed cpDNA restriction patterns either identical to or highly similar to that of the mt+ parent. We propose that cpDNA molecules are predominantly transmitted by the mt+ parent in both F1 and B1 generations but that selection favors survival of F1 progeny with recombinant chloroplast genomes which avoid interspecific incompatibilities. On the surface, the inheritance of recombinant cpDNA contrasts with the simultaneous uniparental inheritance of two putative chloroplast markers (sr-2 and er-nM1 (+)). However, it may be that these two markers are by chance associated with cpDNA sequences of the mt+ parent which were selected in all F1 hybrids.

Characterization of chloroplast DNA in Chlamydomonas eugametos and C. moewusii and its inheritance in hybrid progeny

The density, molecular weight, and cellular repetition of DNA molecules associated with the β-DNA satellite of the interfertile algae Chlamydomonas eugametos and C. moewusii are reported. The similarities between these values and those for the chloroplast DNA (cpDNA) in the related alga Chlamydomonas reinhardtii indicate that these satellites represent cpDNA. The buoyant densities of C. eugametos and C. moewusii cpDNAs are indistinguishable from one another, as are those of their respective nuclear DNAs. These densities differ slightly from the densities of the homologous components of C. reinhardtii whole cell DNA. All three species differ with respect to additional minor satellite DNAs and low molecular weight DNAs of unknown cellular location.Differences in the Aval and Smal restriction endonuclease fragmentation patterns of C. eugametos and C. moewusii cpDNAs were employed to study the inheritance of cpDNA in an F1 hybrid which had inherited a non-Mendelian streptomycin resistance marker (sr-2) from the C. eugametos mating-type plus (mt (+)) parent and in two homoplasmic mitotic segregants from a B 1 hybrid (F1 × C. moewusii) which had been initially heteroplasmic for the resistance marker. Although the cpDNA patterns in the F1 hybrid were similar to those of the C. eugametos ml (1) parent, important differences were noted which suggest that recombination between C. eugametos and C. moewusii cpDNA had occurred. Homoplasmic streptomycin resistant and sensitive mitotic segregants recovered from the B1 hybrid product reveal Aval restriction patterns similar to those of the respective resistant and sensitive parents. These data are consistent with the hypothesis that the sr-2 marker is located in cpDNA and that C. eugametos and C. moewusii cpDNA sequences can coexist in the same chloroplast and, at least sometimes, segregate without extensive recombination. The transmission of low molecular weight DNAs characteristic of C. moewusii but of unknown cellular origin shows no direct correlation with the transmission of the sr-2 marker.

Observations of the effect of ionization-potential depression in hot dense plasma

The newly commissioned Orion laser system has been used to study dense plasmas created by a combination of short pulse laser heating and compression by laser driven shocks. Thus the plasma density was systematically varied between 1 and 10  g/cc by using aluminum samples buried in plastic foils or diamond sheets. The aluminum was heated to electron temperatures between 500 and 700 eV allowing the plasma conditions to be diagnosed by K-shell emission spectroscopy. The K-shell spectra show the effect of the ionization potential depression as a function of density. The data are compared to simulated spectra which account for the change in the ionization potential by the commonly used Stewart and Pyatt prescription and an alternative due to Ecker and Kröll suggested by recent x-ray free-electron laser experiments. The experimental data are in closer agreement with simulations using the model of Stewart and Pyatt.

Resonant Kα spectroscopy of solid-density aluminum plasmas

The x-ray intensities made available by x-ray free electron lasers (FEL) open up new x-ray matter interaction channels not accessible with previous sources. We report here on the resonant generation of Kα emission, that is to say the production of copious Kα radiation by tuning the x-ray FEL pulse to photon energies below that of the K edge of a solid aluminum sample. The sequential absorption of multiple photons in the same atom during the 80 fs pulse, with photons creating L-shell holes and then one resonantly exciting a K-shell electron into one of these holes, opens up a channel for the Kα production, as well as the absorption of further photons. We demonstrate rich spectra of such channels, and investigate the emission produced by tuning the FEL energy to the K-L transitions of those highly charged ions that have transition energies below the K edge of the cold material. The spectra are sensitive to x-ray intensity dependent opacity effects, with ions containing L-shell holes readily reabsorbing the Kα radiation.

Direct measurements of the ionization potential depression in a dense plasma

We have used the Linac Coherent Light Source to generate solid-density aluminum plasmas at temperatures of up to 180 eV. By varying the photon energy of the x rays that both create and probe the plasma, and observing the K-α fluorescence, we can directly measure the position of the K edge of the highly charged ions within the system. The results are found to disagree with the predictions of the extensively used Stewart-Pyatt model, but are consistent with the earlier model of Ecker and Kröll, which predicts significantly greater depression of the ionization potential.

Problem based review: pleuritic chest pain

Pleuritic pain, a sharp discomfort near the chest wall exacerbated by inspiration is associated with a number of pathologies. Pulmonary embolus and infection are two common causes but diagnosis can often be challenging, both for experienced physicians and trainees. The underlying anatomy and pathophysiology of such pain and the most common aetiologies are presented. Clinical symptoms and signs that may arise alongside pleuritic pain are then discussed, followed by an introduction to the diagnostic tools such as the Wells’ score and current guidelines that can help to select the most appropriate investigation(s). Management of pulmonary embolism and other common causes of pleuritic pain are also discussed and highlighted by a clinical vignette.

Electronic structure of warm dense copper studied by ultrafast x-ray absorption spectroscopy

We use time-resolved x-ray absorption spectroscopy to investigate the unoccupied electronic density of states of warm dense copper that is produced isochorically through the absorption of an ultrafast optical pulse. The temperature of the superheated electron-hole plasma, which ranges from 4000 to 10 000 K, was determined by comparing the measured x-ray absorption spectrum with a simulation. The electronic structure of warm dense copper is adequately described with the high temperature electronic density of state calculated by the density functional theory. The dynamics of the electron temperature is consistent with a two-temperature model, while a temperature-dependent electron-phonon coupling parameter is necessary.

Decay of cystalline order and equilibration during the solid-to-plasma transition induced by 20-fs microfocused 92-eV free-electron-laser pulses

We have studied a solid-to-plasma transition by irradiating Al foils with the FLASH free electron laser at intensities up to 10(16)  W/cm(2). Intense XUV self-emission shows spectral features that are consistent with emission from regions of high density, which go beyond single inner-shell photoionization of solids. Characteristic features of intrashell transitions allowed us to identify Auger heating of the electrons in the conduction band occurring immediately after the absorption of the XUV laser energy as the dominant mechanism. A simple model of a multicharge state inverse Auger effect is proposed to explain the target emission when the conduction band at solid density becomes more atomiclike as energy is transferred from the electrons to the ions. This allows one to determine, independent of plasma simulations, the electron temperature and density just after the decay of crystalline order and to characterize the early time evolution.

Saturated ablation in metal hydrides and acceleration of protons and deuterons to keV energies with a soft-x-ray laser

Studies of materials under extreme conditions have relevance to a broad area of research, including planetary physics, fusion research, materials science, and structural biology with x-ray lasers. We study such extreme conditions and experimentally probe the interaction between ultrashort soft x-ray pulses and solid targets (metals and their deuterides) at the FLASH free-electron laser where power densities exceeding 10(17) W/cm(2) were reached. Time-of-flight ion spectrometry and crater analysis were used to characterize the interaction. The results show the onset of saturation in the ablation process at power densities above 10(16) W/cm(2). This effect can be linked to a transiently induced x-ray transparency in the solid by the femtosecond x-ray pulse at high power densities. The measured kinetic energies of protons and deuterons ejected from the surface reach several keV and concur with predictions from plasma-expansion models. Simulations of the interactions were performed with a nonlocal thermodynamic equilibrium code with radiation transfer. These calculations return critical depths similar to the observed crater depths and capture the transient surface transparency at higher power densities.

Rubyspira, new genus and two new species of bone-eating deep-sea snails with ancient habits

Rubyspira, a new genus of deep-sea snails (Gastropoda: Abyssochrysoidea) with two living species, derives its nutrition from decomposing whalebones. Molecular phylogenetic and morphological evidence places the new genus in an exclusively deep-sea assemblage that includes several close relatives previously known as fossils associated with Cretaceous cold seeps, plesiosaur bones, and Eocene whalebones. The ability to exploit a variety of marine reducing environments may have contributed to the evolutionary longevity of this gastropod lineage.