Historical Review on Sugarcane Streak Mosaic Virus That Has Recently Emerged in Africa.

Sugarcane streak mosaic virus (SCSMV), now assigned to the genus Poacevirus of the family Potyviridae, was reported for the first time in 1932 in Louisiana and was believed to be strain F of sugarcane mosaic virus (SCMV) for more than six decades. SCMV-F was renamed SCSMV in 1998 after partial sequencing of its genome and phylogenetic investigations. Following the development of specific molecular diagnostic methods in the 2000s, SCSMV was recurrently found in sugarcane exhibiting streak mosaic symptoms in numerous Asian countries, but not in the Western hemisphere or in Africa. In this review, we give an overview of the current knowledge on this disease and the progression in research on SCSMV. This includes symptoms, geographical distribution and incidence, diagnosis and genetic diversity of the virus, epidemiology, as well as control. Finally, we highlight future challenges as sugarcane streak mosaic has recently been found in Africa where this disease represents a new threat to sugarcane production.

Diagnostic Performance of Extracellular Volume Quantified by Dual-Layer Dual-Energy CT for Detection of Acute Myocarditis.

BACKGROUND: Myocardial extracellular volume (ECV) is a marker of the myocarditis inflammation burden and can be used for acute myocarditis diagnosis. Dual-energy computed tomography (DECT) enables its quantification with high concordance with cardiac magnetic resonance (CMR). PURPOSE: To investigate the diagnostic performance of myocardial ECV quantified on a cardiac dual-layer DECT in a population of patients with suspected myocarditis, in comparison to CMR. METHODS: 78 patients were included in this retrospective monocenter study, 60 were diagnosed with acute myocarditis and 18 patients were considered as a control population, based on the 2009 Lake and Louise criteria. All subjects underwent a cardiac DECT in acute phase consisted in an arterial phase followed by a late iodine enhancement phase at 10 min after injection (1.2 mL/kg, iodinated contrast agent). ECV was calculated using the hematocrit level measured the day of DECT examinations. Non-parametric analyses have been used to test the differences between groups and the correlations between the variables. A ROC curve has been used to identify the optimal ECV cut-off discriminating value allowing the detection of acute myocarditis cases. A p value < 0.05 has been considered as significant. RESULTS: The mean ECV was significantly higher (p < 0.001) for the myocarditis group compared to the control (34.18 ± 0.43 vs. 30.04 ± 0.53%). A cut-off value of ECV = 31.60% (ROC AUC = 0.835, p < 0.001) allows to discriminate the myocarditis with a sensitivity of 80% and a specificity of 78% (positive predictive value = 92.3%, negative predictive value = 53.8% and accuracy = 79.5%). CONCLUSION: Myocardial ECV enabled by DECT allows to diagnose the acute myocarditis with a cut-off at 31.60% for a sensitivity of 80% and specificity of 78%.

Iodine Absorption Cells Purity Testing.

This article deals with the evaluation of the chemical purity of iodine-filled absorption cells and the optical frequency references used for the frequency locking of laser standards. We summarize the recent trends and progress in absorption cell technology and we focus on methods for iodine cell purity testing. We compare two independent experimental systems based on the laser-induced fluorescence method, showing an improvement of measurement uncertainty by introducing a compensation system reducing unwanted influences. We show the advantages of this technique, which is relatively simple and does not require extensive hardware equipment. As an alternative to the traditionally used methods we propose an approach of hyperfine transitions' spectral linewidth measurement. The key characteristic of this method is demonstrated on a set of testing iodine cells. The relationship between laser-induced fluorescence and transition linewidth methods will be presented as well as a summary of the advantages and disadvantages of the proposed technique (in comparison with traditional measurement approaches).

Effect of pulmonary valve replacement on left ventricular function in patients with tetralogy of Fallot.

Pulmonary valve regurgitation is the most common complication after complete repair of tetralogy of Fallot. The benefits of pulmonary valve replacement (PVR) on right ventricular (RV) volumes is well established. However, the effect on left ventricular (LV) function is still debated. We aimed to determine the evolution of LV function after PVR and assess the contribution of the interventricular septum (IVS) motion. A total of 21 patients (mean age 30.1 ± 14.1 years) presenting with a history of complete repair of tetralogy of Fallot and requiring PVR prospectively underwent cardiac magnetic resonance imaging before and after PVR to measure the end-diastolic volume (EDV), end systolic volume, and ejection fraction for the LV and RV chambers. Maximal excursion of the IVS was also calculated to quantify abnormal septal motion. The LV-EDV and LV-end systolic volume was 80 ± 27 and 40 ± 19.5 ml/m(2) before PVR and 81.5 ± 23 and 35 ± 14 ml/m(2) after PVR, respectively, leading to a significant increase in LV ejection fraction of 6.1 ± 4.9% (51 ± 8.2% before and 57 ± 6.8% after PVR, p = 0.0003). Also, a significant reduction in RV-EDV (p = 0.0001) and RV end-systolic volume (p = 0.0001) was seen but without improvement in the RV ejection fraction. The maximum IVS excursion decreased after PVR (9.2 ± 3.4 mm before and 6.8 ± 3.6 mm after; p = 0.002). LV ejection fraction improvement correlated with RV-EDV before PVR (ρ = 0.43; p = 0.049). The maximum IVS excursion correlated with RV-EDV before and after PVR but was independent of LV ejection fraction improvement. In conclusion, the results of the present study have demonstrated a significant improvement in LV ejection fraction after PVR that correlated with the pre-PVR RV-EDV but was independent of IVS motion improvement.

Carotid intima-media and adventitial thickening: comparison of new and established ultrasound and magnetic resonance imaging techniques.

OBJECTIVE: Carotid intima-media thickness is a well established non-invasive surrogate marker of cardiovascular disease, however there is evidence that structural modification of the arterial adventitia also accompanies cardiovascular risk factors and might be involved causally in atherosclerosis. We sought to determine the relative contributions of the intima-media and adventitia to variation in ultrasound and magnetic resonance derived measures of carotid wall thickness. METHODS: Carotid ultrasound and magnetic resonance imaging were undertaken in 20 participants. Carotid intima-media thickness, carotid extra-media thickness (which incorporates the arterial adventitia) and total wall thickness (a combined near-wall intima-media thickness and carotid extra-media thickness) using high-resolution ultrasound, and wall thickness using magnetic resonance imaging, were obtained. RESULTS: All ultrasound-derived measures of the arterial wall thickness were highly correlated with wall thickness by magnetic resonance imaging (all P<0.001); as expected the total wall thickness by ultrasound measure was most tightly correlated (correlation coefficient=0.814, P<0.0001). In multivariable models, there was evidence that both carotid intima-media thickness and carotid extra-media thickness contributed independently to the variance in wall thickness by magnetic resonance imaging, especially for the most severe focal thickening. Measures of carotid wall thickness that incorporated all three layers of the arterial wall were more closely correlated with the number of cardiovascular risk factors than carotid intima-media thickness alone. CONCLUSIONS: These results indicate that the arterial adventitia is an important contributor to the wall thickness measure derived by magnetic resonance imaging, and that carotid extra-media thickness likely provides additional information concerning arterial structure than that obtained from carotid intima-media thickness alone.

Could an osteoinductor result in degeneration of a neurofibroma in NF1?

We report a case of fatal evolution of neurofibromatosis in a young boy. A laminectomy was performed when he was 9 years old. A secondary hyperkyphosis led to many surgeries resulting in recurrent malunions. When he was 23 years old, a breakage of his rods was treated by a new instrumentation and a T12-L1 interbody cage fitted with rh-BMP. Five months later, he developed a huge posterior tumour on his back. The biopsy diagnosed a neurofibrosarcoma. The growth of the tumour was extremely rapid. He died after several months from a septic shock. NF1 is characterised by neurofibromas that have a possibility of malign degeneration and conversion to a sarcoma. However, the chronology, rapidity of evolution and the exceptional volume of the tumour made us wonder whether the BMP had a part of responsibility as osteoinductor in the malignant degeneration, in this particular case, of neurofibromatosis. It seemed important to point out this case to the medical community.

Modified electrocardiograph-triggered black-blood turbo spin-echo technique to improve T1-weighting in contrast-enhanced MRI of atherosclerotic carotid arteries.

PURPOSE: To assess the efficacy of a modified electrocardiograph (EKG)-triggered black-blood T1W (T1W) spin-echo sequence in improving contrast on post-gadolinium high-resolution carotid plaque imaging by implementing heart-rate-independent contrast preparation. MATERIALS AND METHODS: We used a standard EKG-triggered double inversion-recovery (DIR) turbo spin-echo (TSE) sequence modified with the addition of an extra saturation (90 degrees ) radio frequency (RF) pulse placed immediately after the DIR module, shortening the repetition time to a fixed value of 400 msec. A total of 10 patients with atherosclerotic disease were included in the study. Postinjection intraplaque contrast measurements were performed on each patient for the standard and the modified sequence. RESULTS: Post-gadolinium-injection intraplaque contrast was 31.7 +/- 12.8% with the standard T1W sequence (nT1-TSE), and 45.3 +/- 17.2% with the modified T1W sequence (mT1-TSE), showing a significant contrast enhancement of 13.6% (P < 0.001) without significant image quality modification. CONCLUSION: The addition of a RF pulse to the standard EKG-triggered T1W TSE sequence increased intraplaque contrast without increasing sequence acquisition time. Furthermore, it appeared to be a robust technique, easy to implement on clinical scanners.

The reliability of high resolution MRI in the measurement of early stage carotid wall thickening.

PURPOSE: To study the repeatability of common carotid mean wall thickness (MWT) measured with high resolution MRI, in comparison with intima media thickness (IMT) assessed by ultrasound and to investigate the relative capabilities of these two modalities. MATERIALS AND METHODS: Ten healthy volunteers and 10 subjects with carotid artery atherosclerosis were imaged with both high resolution MRI and US. Measurement of both MWT and IMT was performed by three blinded observers. Intra- and inter-observer repeatability was calculated and a Bland-Altman plot used to compare IMT and MWT. Circumferential variation in arterial wall thickness was also evaluated. RESULTS: Intra- and inter-observer repeatability were comparable between IMT and MWT. The Bland-Altman plot showed a difference between IMT and MWT in controls with a trend towards equivalence in atherosclerotic patients. Analysis of circumferential variation in wall thickness by MRI identified greater focal thickening in patients compared with controls (p<0.001), which was not evident with ultrasound (p=0.98). CONCLUSION: MRI and ultrasound have similar repeatability for the assessment of carotid wall thickness. There are differences between MWT and IMT, potentially due to the inclusion of the adventitia by MRI which, in addition to better detection of focal thickening, may provide a more complete estimation of early stage atherosclerosis.

Swallowing, arterial pulsation, and breathing induce motion artifacts in carotid artery MRI.

PURPOSE: To identify and quantify the potential sources of motion in carotid artery imaging. MATERIALS AND METHODS: Two healthy volunteers and 12 patients (20-75 years old) with atherosclerotic disease were scanned on a Philips Intera 1.5T system. A single-shot balanced-fast field echo (bFFE) sequence was used to acquire real-time axial views of the carotid artery wall (three images per second). A three-step acquisition protocol was performed to analyze the three types of motion (arterial pulsation, breathing, and swallowing) separately. The isocenter carotid artery motion amplitude in either the x or y direction was measured. Radial variation in the carotid lumen between the systolic and diastolic phases was analyzed. Motion frequency was reported for each patient. RESULTS: Significant motion related to arterial pulsation (amplitude = 0.27-0.93 mm, mean = 0.6, SD = 0.19), breathing (amplitude = 0.5-3.6 mm, mean = 1.56, SD = 0.99)), and swallowing (amplitude = 1.4-9.2 mm, mean = 4.7, SD = 2.4) were visualized. CONCLUSION: Pulsation, breathing, and swallowing are sources of significant motion in the carotid artery wall. Such motion should be considered in the future to improve carotid artery image quality.