David Murphy

T7 RNA polymerase-directed expression of an antibody fragment transgene in plastids causes a semi-lethal pale-green seedling phenotype

A T7 promoter-controlled transgene, AbL, encoding a camel single-domain antibody fragment that binds to the model antigen chicken egg-white lysozyme was introduced into the plastid genome of tobacco. AbL expression was activated in the transplastomic line by introducing a nuclear transgene, ST7, encoding a light-regulated plastid-targeted T7RNAP by cross-pollination. The resulting AbL × ST7 progeny seedlings developed a pale-green phenotype and ceased growth soon after germination. High levels of AbL transcripts accumulated in AbL × ST7 seedlings and expression of functional AbL antibody was detected by ELISA. Transplastomic AbL plants were also crossed with nuclear-transformed tobacco plants containing a salicylic acid-inducible transgene encoding a plastid-targeted T7RNAP (PR-T7 transgene). The resulting AbL × PR-T7 progeny were wild-type in appearance but were slow growing and prone to wilting even when provided with adequate water. Although AbL transcription was inducible by treating AbL × PR-T7 leaves with salicylic acid, high levels of T7RNAP-dependent AbL transcripts also accumulated in the absence of induction. However, AbL antibody did not accumulate at levels detectable by immunoblotting or ELISA in AbL × PR-T7 plants despite the fact that total leaf RNA containing AbL transcripts was capable of directing AbL antibody synthesis in an E. coli-derived in vitro translation system.

Recent developments in the use of computed tomography scanners in coronary artery imaging

ABSTRACT Introduction: Within the past decade, substantial evolution of Coronary CT Angiography (CCTA) has affected evaluation and management of coronary artery disease. In particular, technical advancement of hardware technology and image reconstruction of CT scanners have played an important role in this context making it possible to acquire abundant data with excellent temporal and spatial resolution within a shorter scan time. In addition, a concern related to the high radiation exposure in the initial noninvasive coronary artery imaging has triggered improvement in dose reduction techniques. Areas covered: In this review article, we have focused on recent technological developments in CT scanners and the impact of these developments on CCTA parameters. Expert Commentary: CCTA plays an important role in coronary artery disease management, and technical development of the CT scanners can be expected to address and remedy technical limitations.

Disordered breathing during sleep and exercise in idiopathic pulmonary fibrosis and the role of biomarkers

BACKGROUND AND OBJECTIVE Idiopathic pulmonary fibrosis (IPF) patients report fatigue, possibly reflecting sleep disturbance, but little is known about sleep-related changes. We compared ventilation and gas exchange during sleep and exercise in a cohort of IPF patients, and evaluated associations with selected biological markers. METHODS Twenty stable IPF patients (aged 67.9 ± 12.3 [SD]) underwent overnight polysomnography following an acclimatization night. Cardiopulmonary exercise testing was performed and inflammatory markers measured including TNF-α, IL-6, CXCL8, C-C motif ligand 18 (CCL-18) and C-reactive protein (CRP) RESULTS: Nine patients had sleep-disordered breathing (SDB) with an apnea-hypopnea frequency (AHI) ≥ 5/h, but only two had Epworth sleepiness score ≥ 10, thus having an obstructive sleep apnea syndrome. Sleep quality was poor. Transcutaneous carbon dioxide tension (PtcCO2) rose by 2.56 ± 1.59 kPa overnight (P = 0.001), suggesting hypoventilation. Oxygen saturation (SaO2) was lower during sleep than exercise (P < 0.01), and exercise variables correlated with resting pulmonary function. CCL-18 and CRP levels were elevated and correlated with PtcCO2 rise during sleep (P < 0.05). CCL-18 negatively correlated with diffusion capacity of carbon monoxide (DLCO), arterial oxygen (PaO2) and mean arterial carbon dioxide (PaCO2) (P < 0.05) and CRP negatively correlated with DLCO, PaO2, sleep SaO2 and oxygen uptake (VO2) during exercise (P < 0.05). CONCLUSIONS IPF patients desaturate more during sleep than exercise; thus, nocturnal pulse oxymetry could be included in clinical assessment. CCL-18 and CRP levels correlate with physiological markers of fibrosis.

IgG4-Related Disease With Coronary Arteritis

A 53-year-old male patient with chronic renal failure and biopsy-proven Immunoglobulin G4 (IgG4) renal involvement presented with complains of chest pain and syncope. An ECG showed lateral ST segment depressions concerning for myocardial ischemia. The patient underwent coronary catheterization, which revealed multifocal aneurysms and severe stenosis. A cardiac computerized tomographic angiogram was performed to further characterize aneurysms, which showed aneurysms involving left main, proximal left anterior descending artery, and proximal right coronary artery (Figures 1 and 2). Circumferential mural thickening with associated enhancement of the wall of the coronary arteries, particularly at the site of the stenoses, was concerning for vasculitis. A small pulmonary artery aneurysm was seen in the right upper lobe (Figure 3 …

Idiopathic pulmonary fibrosis with emphysema: evidence of synergy among emphysema and idiopathic pulmonary fibrosis in smokers.

BACKGROUND: Emphysema and fibrosis, typically the idiopathic pulmonary fibrosis (IPF) form of usual interstitial pneumonia (UIP), can co-exist as combined pulmonary fibrosis emphysema (CPFE). It is unknown whether there is a pathobiologic basis for CPFE beyond the coexistence of fibrosis and emphysema. The aim of this study was to ascertain radiologic differences in severity of fibrosis and emphysema in smokers with IPF versus other forms of UIP. METHODS: Computed tomography thorax images were prospectively rescored in retrospectively identified smokers (minimum 5-pack-year history) with radiologic UIP (any etiology). Radiologic severity (emphysema/fibrosis/reticulation) was scored in consensus by two radiologists, blinded to clinical details, across 5 lung regional levels, and then correlated with clinical data. RESULTS: For the whole cohort (IPF, n = 102; non-IPF UIP [mainly rheumatoid arthritis/asbestosis/scleroderma], n = 30), IPF and non-IPF UIP smokers were similar regarding pack-year, age, gender, and lung function (P > .1). IPF smokers had greater whole lung fibrosis and reticulation scores (P < .04 in all cases). CPFE was present in n = 61 (IPF, n = 49; non-IPF UIP, n = 12). Compared with smokers with non-IPF CPFE, smokers with IPF and emphysema (IPFE) were similar regarding confounders (P > .1). There were significantly greater regional reticulation severity (P = .009), cumulative emphysema severity (P = .04), and cumulative reticulation severity (P < .001) scores in IPFE versus non-IPF CPFE. CONCLUSIONS: When controlled for confounders, smokers with IPFE have worse radiologic CPFE than other smokers with non-IPF UIP and emphysema, suggesting an interactive synergy among IPF, emphysema, and smoking, with more extensive emphysema due to either inherent susceptibility and/or traction effects. IPFE should be considered separately from other CPFE in future work. It is currently unknown whether CPFE is a distinct pathobiologic entity; therefore, we identified subjects with radiologic UIP (any etiology) who had been similarly exposed to smoke, and asked whether there are differences in the extent/severity of radiologic fibrosis and/or emphysema in those with IPF versus individuals with non-IPF UIP. Although relevant confounders were similar, IPF smokers had greater whole lung fibrosis and reticulation scores than smokers with secondary forms of UIP, and in the CPFE subgroup, smokers with IPF/emphysema had worse radiologic CPFE findings than smokers with non-IPF UIP/emphysema. It is shown for the first time that relevant confounding variables do not explain the observed excess radiologic severity of emphysema and fibrosis in smokers with IPF compared with smokers with non-IPF UIP, lending support to the hypothesis that there is a pathobiologic mechanism or synergy involved in IPF with emphysema that is distinct from the mere co-existence of UIP and emphysematous processes.

Cross-sectional imaging of aortic infections

AbstractAortic infections are uncommon clinical entities, but are associated with high rates of morbidity and mortality. In this review, we focus on the cross-sectional imaging appearance of aortic infections, including aortic valve endocarditis, pyogenic aortitis, mycotic aneurysm and aortic graft infections, with an emphasis on CT, MRI and PET/CT appearance. Teaching Points • Aortic infections are associated with high morbidity and mortality. • CT, MRI and FDG PET/CT play complementary roles in aortic infection imaging. • Radiologists should be vigilant for aortic infection manifestations to ensure timely diagnosis.

Magnetic resonance enterography findings as predictors of clinical outcome following antitumor necrosis factor treatment in small bowel Crohn's disease.

Aims To determine whether specific magnetic resonance enterography (MRE) findings can predict outcome following commencement of antitumor necrosis factor (aTNF) in small bowel Crohn’s disease (CD) Patients and methods This was a single-centre retrospective study of patients with CD who commenced aTNF (infliximab or adalimumab) between 2007 and 2013. Patients who had an MRE within 6 months before commencing aTNF were included. The primary end-point was the need for CD-related surgery. The secondary end-points were time to surgery and time to treatment failure. The relationship between these end-points, clinical variables and specific MRE findings were studied. Results Four hundred and eighteen patients commenced aTNF for CD during the study period. Seventy-five patients had an MRE within 6 months before commencing aTNF (30 infliximab; 45 adalimumab). The median time from MRE to commencing aTNF was 43 days (IQR 19.5–87 days). Eighteen of 75 (24%) had surgery during a median follow-up of 16.7 months (IQR 9.0–30.1 months). Patients with small bowel stenosis (SBS) on MRE were at a significantly higher risk of requiring surgery: 12/18 (66.7%) versus 6/57 (10.5%) (P<0.001). Time to surgery was significantly shorter in patients with SBS on MRE (P<0.001). In a multivariate analysis, SBS (P<0.0001, hazard ratio 26.45, 95% confidence interval 5.45–128.49) and presence of penetrating complications (P=0.003, hazard ratio 36.53, 95% confidence interval 3.40–393.19) were associated independently with time to surgery. Conclusion SBS and penetrating complications on MRE are associated independently with a need for early surgery and treatment failure in patients commencing aTNF.

Use of Cardiac Computerized Tomography to Predict Neo–Left Ventricular Outflow Tract Obstruction Before Transcatheter Mitral Valve Replacement

Although the incidence of mitral stenosis has declined precipitously in the Western world due to the reduced incidence of rheumatic heart disease, mitral regurgitation remains one of the most common valvular pathologies.[1][1] Many patients affected by severe mitral valve disease are elderly with

Pulmonary fibrosis: tissue characterization using late-enhanced MRI compared with unenhanced anatomic high-resolution CT.

PURPOSE We aimed to prospectively evaluate anatomic chest computed tomography (CT) with tissue characterization late gadolinium-enhanced magnetic resonance imaging (MRI) in the evaluation of pulmonary fibrosis (PF). METHODS Twenty patients with idiopathic pulmonary fibrosis (IPF) and twelve control patients underwent late-enhanced MRI and high-resolution CT. Tissue characterization of PF was depicted using a segmented inversion-recovery turbo low-angle shot MRI sequence. Pulmonary arterial blood pool nulling was achieved by nulling main pulmonary artery signal. Images were read in random order by a blinded reader for presence and extent of overall PF (reticulation and honeycombing) at five anatomic levels. Overall extent of IPF was estimated to the nearest 5% as well as an evaluation of the ratios of IPF made up of reticulation and honeycombing. Overall grade of severity was dependent on the extent of reticulation and honeycombing. RESULTS No control patient exhibited contrast enhancement on lung late-enhanced MRI. All IPF patients were identified with late-enhanced MRI. Mean signal intensity of the late-enhanced fibrotic lung was 31.8±10.6 vs. 10.5±1.6 for normal lung regions, P < 0.001, resulting in a percent elevation in signal intensity from PF of 204.8%±90.6 compared with the signal intensity of normal lung. The mean contrast-to-noise ratio was 22.8±10.7. Late-enhanced MRI correlated significantly with chest CT for the extent of PF (R=0.78, P = 0.001) but not for reticulation, honeycombing, or coarseness of reticulation or honeycombing. CONCLUSION Tissue characterization of IPF is possible using inversion recovery sequence thoracic MRI.

Assessing fibrosis in pulmonary sarcoidosis: late-enhanced MRI compared to anatomic HRCT imaging

Accurate imaging detection and quantification of fibrotic pulmonary sarcoid is important for diagnosis, treatment and prognosis. 1–3 The gold-standard non-invasive imaging test remains high resolution chest computed tomography (HRCT), which is now widely utilized worldwide in the diagnosis and follow-up of sarcoid, has been used extensively in numerous clinical drug trials and is an outcome measure in sarcoid. 4–7 However, it typically relies on the anatomical depiction of fibrosis, characterized by traction bronchiectasis, reticulation and honeycombing.8,9 A major limitation of this approach relates to anatomical mimics such as emphysema and chronic pneumoconiosis, which can have similar imaging appearances.6 Imaging modalities such as magnetic resonance imaging (MRI) have also been used extensively in the investigation of fibrotic pulmonary sarcoid with varying degrees of success.10–16 The advantages of MRI are its lack of ionizing radiation and versatile tissue characterization abilities, whilst its limitations relate principally to spatial resolution and contrast-to-noise ratios in depicting the lung parenchyma compared to HRCT. Although several non-contrast and contrast enhanced MRI protocols have been published to assess pulmonary fibrosis, none have acquired widespread acceptance in routine clinical practice.17 Contrast late-enhanced cardiac MRI has been utilized in cardiac imaging to detect, localize and quantify myocardial fibrosis.18,19 Many studies have shown that a specific double-inversion recovery sequence acquired ∼10 min after intravenous contrast administration demonstrates contrast wash out of normal myocardium and late enhancement of myocardial fibrosis, the increased gadolinium concentration within myocardial fibrosis corresponding to the increased extracellular space characteristic of fibrotic tissue.20 Since gadolinium is an extracellular contrast agent, it diffuses out of the blood pool and normal tissues and concentrates in tissues with an enlarged extracellular space. Such late enhancement can be exploited to detect myocardial fibrosis in many cardiomyopathies.18,21 We hypothesized that since …