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1.
Int J Cardiovasc Imaging ; 36(2): 299-307, 2020 Feb.
Article in English | MEDLINE | ID: mdl-31673849

ABSTRACT

Tako-tsubo cardiomyopathy (TTC) is characterized by the presence of transient left ventricular (LV) dysfunction. Whether left atrial (LA) function is also impaired in this setting is unclear. To assess prospectively LA peak systolic longitudinal strain (LAS) by two-dimensional strain at the acute phase of TTC and after recovery and its association with in-hospital complications. 40 patients with typical TTC (mean age 79.5 ± 10 years) underwent transthoracic-Doppler echocardiography at the acute phase and at follow-up (32 ± 18 days later), including the measurement of the LAS (mean of maximal strain from the 4-2 chamber views). A control group of 15 patients (75 ± 7 years, 13 women) without overt cardiovascular disease served as a comparative group. In-hospital complication was a composite of death, heart failure, cardiogenic shock, LV thrombus, and sustained ventricular arrhythmia. In the TTC group, LAS improved significantly between the two examinations from 15 ± 5.5% to 27 ± 8% (p < 0.01) whereas LA volume did not change (p = NS). In the control group LAS was 30 ± 4% (p < 0.01 vs. TTC acute phase, p = NS vs. TTC follow-up). In TTC, at the acute phase LAS was independently correlated to LV global longitudinal strain (LVGLS), and after recovery to E/e', and the change of LAS was independently correlated to the change of the LVGLS (all, p < 0.01). Furthermore LAS was independently correlated to in-hospital complications (p < 0.01). LA function (reservoir) is transiently impaired in TTC and associated to in-hospital complications. Furthermore, the improvement of LAS parallel the dynamic improvement of LVGLS suggests that TTC induces a transient global left heart dysfunction.


Subject(s)
Atrial Function, Left , Echocardiography, Doppler , Heart Atria/diagnostic imaging , Takotsubo Cardiomyopathy/diagnostic imaging , Aged , Aged, 80 and over , Case-Control Studies , Disease Progression , Female , Heart Atria/physiopathology , Hospital Mortality , Hospitalization , Humans , Male , Predictive Value of Tests , Prospective Studies , Takotsubo Cardiomyopathy/complications , Takotsubo Cardiomyopathy/mortality , Takotsubo Cardiomyopathy/physiopathology , Ventricular Function, Left
2.
AJNR Am J Neuroradiol ; 40(4): 655-660, 2019 04.
Article in English | MEDLINE | ID: mdl-30872416

ABSTRACT

BACKGROUND AND PURPOSE: Intracranial hemorrhage is a known complication following endovascular thrombectomy. The radiologic characteristics of a CT scan may assist with hemorrhage risk stratification. We assessed the radiologic predictors of intracranial hemorrhage following endovascular therapy using data from the INTERRSeCT (Identifying New Approaches to Optimize Thrombus Characterization for Predicting Early Recanalization and Reperfusion With IV Alteplase and Other Treatments Using Serial CT Angiography) study. MATERIALS AND METHODS: Patients undergoing endovascular therapy underwent baseline imaging, postprocedural angiography, and 24-hour follow-up imaging. The primary outcome was any intracranial hemorrhage observed on follow-up imaging. The secondary outcome was symptomatic hemorrhage. We assessed the relationship between hemorrhage occurrence and baseline patient characteristics, clinical course, and imaging factors: baseline ASPECTS, thrombus location, residual flow grade, collateralization, and clot burden score. Multivariable logistic regression with backward selection was used to adjust for relevant covariates. RESULTS: Of the 199 enrolled patients who met the inclusion criteria, 46 (23%) had an intracranial hemorrhage at 24 hours. On multivariable analysis, postprocedural hemorrhage was associated with pretreatment ASPECTS (OR, 1.56 per point lost; 95% CI, 1.12-2.15), clot burden score (OR, 1.19 per point lost; 95% CI, 1.03-1.38), and ICA thrombus location (OR, 3.10; 95% CI, 1.07-8.91). In post hoc analysis, clot burden scores of ≤3 (sensitivity, 41%; specificity, 82%; OR, 3.12; 95% CI, 1.36-7.15) and pretreatment ASPECTS ≤ 7 (sensitivity, 48%; specificity, 82%; OR, 3.17; 95% CI, 1.35-7.45) robustly predicted hemorrhage. Residual flow grade and collateralization were not associated with hemorrhage occurrence. Symptomatic hemorrhage was observed in 4 patients. CONCLUSIONS: Radiologic factors, early ischemia on CT, and increased CTA clot burden are associated with an increased risk of intracranial hemorrhage in patients undergoing endovascular therapy.


Subject(s)
Endovascular Procedures/adverse effects , Intracranial Hemorrhages/etiology , Stroke/pathology , Stroke/therapy , Thrombectomy/adverse effects , Aged , Brain Ischemia/pathology , Female , Humans , Male , Middle Aged , Risk Factors , Thrombosis/pathology
3.
Int J Stroke ; 13(9): 949-984, 2018 12.
Article in English | MEDLINE | ID: mdl-30021503

ABSTRACT

The 2018 update of the Canadian Stroke Best Practice Recommendations for Acute Stroke Management, 6th edition, is a comprehensive summary of current evidence-based recommendations, appropriate for use by healthcare providers and system planners caring for persons with very recent symptoms of acute stroke or transient ischemic attack. The recommendations are intended for use by a interdisciplinary team of clinicians across a wide range of settings and highlight key elements involved in prehospital and Emergency Department care, acute treatments for ischemic stroke, and acute inpatient care. The most notable changes included in this 6th edition are the renaming of the module and its integration of the formerly separate modules on prehospital and emergency care and acute inpatient stroke care. The new module, Acute Stroke Management: Prehospital, Emergency Department, and Acute Inpatient Stroke Care is now a single, comprehensive module addressing the most important aspects of acute stroke care delivery. Other notable changes include the removal of two sections related to the emergency management of intracerebral hemorrhage and subarachnoid hemorrhage. These topics are covered in a new, dedicated module, to be released later this year. The most significant recommendation updates are for neuroimaging; the extension of the time window for endovascular thrombectomy treatment out to 24 h; considerations for treating a highly selected group of people with stroke of unknown time of onset; and recommendations for dual antiplatelet therapy for a limited duration after acute minor ischemic stroke and transient ischemic attack. This module also emphasizes the need for increased public and healthcare provider's recognition of the signs of stroke and immediate actions to take; the important expanding role of paramedics and all emergency medical services personnel; arriving at a stroke-enabled Emergency Department without delay; and launching local healthcare institution code stroke protocols. Revisions have also been made to the recommendations for the triage and assessment of risk of recurrent stroke after transient ischemic attack/minor stroke and suggested urgency levels for investigations and initiation of management strategies. The goal of this updated guideline is to optimize stroke care across Canada, by reducing practice variations and reducing the gap between current knowledge and clinical practice.


Subject(s)
Emergency Medical Services/legislation & jurisprudence , Emergency Service, Hospital/legislation & jurisprudence , Ischemic Attack, Transient/therapy , Stroke/therapy , Canada , Critical Care/legislation & jurisprudence , Delivery of Health Care/legislation & jurisprudence , Hospitalization/legislation & jurisprudence , Humans , Inpatients , Stroke/diagnosis
4.
Int J Cardiovasc Imaging ; 33(7): 999-1007, 2017 Jul.
Article in English | MEDLINE | ID: mdl-27752796

ABSTRACT

To test the usefulness of non-invasive coronary flow reserve (CFR) by transthoracic Doppler echocardiography by comparison to invasive fractional flow reserve (FFR) and instantaneous wave-free ratio (IFR), a new vasodilator-free index of coronary stenosis severity, in patients with left anterior descending artery (LAD) stenosis of intermediate severity (IS) and stable coronary artery disease. 94 consecutive patients (mean age 68 ± 10 years) with angiographic LAD stenosis of IS (50-70 % diameter stenosis), were prospectively studied. IFR was calculated as a trans-lesion pressure ratio during the wave-free period in diastole; FFR as distal pressure divided by mean aortic pressure during maximal hyperemia (using 180 µg intracoronary adenosine); and CFR as hyperemic peak LAD flow velocity divided by baseline flow velocity using intravenous adenosine (140 µg/kg/min over 2 min). The mean values of IFR, FFR, and CFR were 0.88 ± 0.07, 0.81 ± 0.09, and 2.4 ± 0.6 respectively. A significant correlation was found between CFR and FFR (r = 0. 68), FFR and IFR (r = 0.6), and between CFR and IFR (r = 0.5) (all, p < 0.01). Using a ROC curve analysis, the best cut-off to detect a significant lesion based on FFR assessment (FFR ≤ 0.8, n = 31) was IFR ≤ 0.88 with a sensitivity (Se) of 74 %, specificity (Sp) of 73 %, AUC 0.81 ± 0.04, accuracy 72 %; and CFR ≤ 2 with a Se = 77 %, Sp = 89 %, AUC 0.88 ± 0.04, accuracy 85 % (all, p < 0.001). In stable patients with LAD stenosis of IS, non-invasive CFR is a useful tool to detect a significant lesion based on FFR. Furthermore, there was a better correlation between CFR and FFR than between CFR and IFR, and a trend to a better diagnostic performance for CFR versus IFR.


Subject(s)
Cardiac Catheterization , Coronary Stenosis/diagnostic imaging , Coronary Vessels/diagnostic imaging , Echocardiography, Doppler , Fractional Flow Reserve, Myocardial , Aged , Area Under Curve , Blood Flow Velocity , Coronary Stenosis/physiopathology , Coronary Vessels/physiopathology , Female , Humans , Hyperemia/physiopathology , Image Interpretation, Computer-Assisted , Male , Middle Aged , Observer Variation , Predictive Value of Tests , Prognosis , Prospective Studies , ROC Curve , Reproducibility of Results , Severity of Illness Index , Signal Processing, Computer-Assisted
5.
Ann Cardiol Angeiol (Paris) ; 65(5): 380-381, 2016 Nov.
Article in English | MEDLINE | ID: mdl-27968774

ABSTRACT

Assessment of the functional significance of left anterior descending coronary artery (LAD) stenosis of intermediate severity is challenging and often based on fractional flow reserve (FFR). The instantaneous wave-free ratio (IFR), a new vasodilator-free index of coronary stenosis severity, and non-invasive coronary flow reserve (CFR) by transthoracic Doppler echocardiography are also potentially useful. A direct comparison of FFR, IFR, and non-invasive CFR has never been performed. Our objective was to test the usefulness of non-invasive CFR by comparison to invasive FFR and IFR in patients with LAD stenosis of angiographic intermediate severity and stable coronary artery disease. METHODS: Ninety-four stable consecutive patients (mean age, 68±10years; 19 women) with angiographic proximal or mid LAD stenosis of intermediate severity (40-70% diameter stenosis on quantitative coronary angiography), were prospectively studied. They underwent IFR that was calculated as a trans-lesion pressure ratio during a specific period of baseline diastole, FFR with intracoronary bolus adenosine (180µg), and CFR using intravenous adenosine (140µg/kg/min over 2min) in the distal part of the LAD, the same day. CFR was defined as hyperemic peak diastolic LAD flow velocity divided by baseline flow velocity and FFR as distal pressure divided by mean aortic pressure during maximal hyperemia. RESULTS: The mean values of IFR, FFR, and CFR were 0.88±0.07, 0.81±0.09, and 2.4±0.6 respectively. A significant correlation was found between CFR and FFR (R=0.63, curvilinear relationship), FFR and IFR (R=0.6, linear relationship), and between CFR and IFR (R=0.5) (all, P<0.01). Using a ROC curve analysis, the best cut-off to detect a significant lesion based on FFR assessment (FFR≤0.8, N=31) was IFR≤0.88 with a sensitivity (Se) of 74%, specificity (Sp) of 73%, AUC 0.81±0.04; and CFR≤2 with a Se=77%, Sp=89%, AUC 0.88±0.04, (all, P<0.001). Based on these cut-offs, discordant results between CFR and FFR were observed in 14 cases (agreement 85%), between CFR and IFR in 26 cases (agreement 72%), and between IFR and FFR in 26 cases (agreement 72%). CONCLUSION: In stable patients with LAD stenosis of intermediate severity, non-invasive CFR is a useful tool to detect a significant lesion based on FFR. Furthermore, there was a better correlation and agreement between CFR and FFR than with IFR.

6.
Ann Cardiol Angeiol (Paris) ; 65(5): 381, 2016 Nov.
Article in English | MEDLINE | ID: mdl-27968775

ABSTRACT

BACKGROUND: It is unclear whether apical rotation (Ar), which in normal setting represents the dominant contributions to LV twist by comparison to basal rotation (Br), predicts viability in acute anterior myocardial infarction (AMI). Our objective was to test the usefulness of Ar as a simple index to predict LV recovery after AMI. METHODS: Fourty-five consecutive patients (mean age 60±14 years, mean LVEF 44±7%) with first AMI treated successfully by primary angioplasty underwent prospectively a comprehensive transthoracic-Doppler echocardiography including analysis of Ar, Br, and LV twist by 2-dimensional speckle tracking, using a basal and apical short axis-views, within 24h after angioplasty and 3-6months later. Recovery was defined as: - the normalization of the wall motion of more than 50% of initial abnormal segments (R1) and; - absolute improvement of LVEF≥10% (R2). RESULTS: A better correlation was found between Ar and LV twist at each stage of the disease than between Br and LV twist (acute phase, R=0.77 vs. R=0.35; follow-up, R=0.9 vs. R=0.3 [all, P<0.001 for Ar, and all, P≤0.05 for Br]). Furthermore, a better correlation was found between Ar and follow-up LVEF (R=0.57), wall motion score index (R=0.44), and global longitudinal strain (R=0.54) (all, P<0.001) than between LV twist and the same parameters (R=0.39; R=0.32; R=0.32 respectively, all P<0.05). (For Br, all, P=NS). Ar as well as LV twist were significantly associated with recovery (all, P<0.01) with an area under the curve (AUC) higher for the former than for the latter (R1, N=18: AUC-Ar=0.81 and AUC-LV twist=0.69, P=0.05; R2, N=19: AUC-Ar=0.82, AUC-LV twist=0.75, P=0.1). In multivariate analysis, Ar remained an independent predictor of recovery R1 and R2 instead of LV twist (all, P≤0.01). Using a ROC curve analysis, the best cut-off of Ar to predict recovery R2 was 6.5°, with Se=77% Sp=85%, P<0.001. CONCLUSION: Apical rotation is an independent predictor of segmental and global LV recovery after anterior acute anterior myocardial infarction treated successfully by primary angioplasty.

7.
Nanotechnology ; 27(47): 475403, 2016 Nov 25.
Article in English | MEDLINE | ID: mdl-27782007

ABSTRACT

We describe methods of Ga droplet consumption in Ga-assisted GaAs nanowires, and their impact on the crystal structure at the tip of nanowires. Droplets are consumed under different group V flux conditions and the resulting tip crystal structure is examined by transmission electron microscopy. The use of GaAsP marker layers provides insight into the behavior of the Ga droplet during different droplet consumption conditions. Lower group V droplet supersaturations lead to a pure zincblende stacking-fault-free tip crystal structure, which improved the performance of a nanowire-based photovoltaic device.

8.
Ann Cardiol Angeiol (Paris) ; 65(5): 363-365, 2016 Nov.
Article in French | MEDLINE | ID: mdl-27427466

ABSTRACT

Paradoxical embolism is rarely demonstrated, often suggested, and the diagnosis has been largely presumptive in most cases. The patent foramen ovale (PFO) is an important predisposing anatomic factor for such a complication. We describe a case where a voluminous thrombus straddling the PFO was diagnosed by echocardiography including the 3D modality, in the setting of acute massive pulmonary embolism. The treatment is not codified in this setting, and the thrombus was successfully removed by surgery, associated with PFO closure, and anticoagulation.


Subject(s)
Echocardiography, Three-Dimensional , Echocardiography, Transesophageal , Embolism, Paradoxical/diagnostic imaging , Embolism, Paradoxical/surgery , Foramen Ovale, Patent/diagnostic imaging , Foramen Ovale, Patent/surgery , Pulmonary Embolism/diagnostic imaging , Pulmonary Embolism/surgery , Thrombosis/diagnostic imaging , Thrombosis/surgery , Anticoagulants/administration & dosage , Combined Modality Therapy , Female , Humans , Middle Aged , Risk Factors
9.
Support Care Cancer ; 23(5): 1459-71, 2015 May.
Article in English | MEDLINE | ID: mdl-25711653

ABSTRACT

BACKGROUND: Extravasation is a potentially severe complication that can occur during the administration of chemotherapy. The scarcity of evidence available makes it difficult to develop an optimal management scheme. The purpose of this guideline is to review the relevant scientific literature on the prevention, management, and treatment of extravasation occurring during the administration of chemotherapy to cancer patients. METHOD: A scientific literature review was conducted using the PubMed search tool. The period covered was from database inception to April 2014, inclusively. Since the literature on extravasation treatment is often empirical, anecdotal, and controversial, the review also identified clinical practice guidelines and expert consensuses published by relevant international organizations and cancer agencies. RESULTS: Identification of potential risk factors and preventive measures can reduce the risk of extravasation. Recognition and management of symptoms are crucial in patients with this complication. Provision of adequate instruction to personnel responsible for administering chemotherapy and to patients on recognizing symptoms, preventing, and managing extravasation is essential. Extravasation can be treated with dry warm or cold compresses and various antidotes such as dimethyl sulfoxide, dexrazoxane, hyaluronidase, or sodium thiosulfate, depending on the agent that has caused extravasation. Patient monitoring to assess the progression or regression of symptoms and to thus take the appropriate measures is necessary. CONCLUSION: Several strategies must be established to ensure that extravasation is recognized and properly managed. Given the evidence available at this time, the Comité de l'évolution des pratiques en oncologie (CEPO) has made recommendations for clinical practice in Quebec.


Subject(s)
Antineoplastic Agents/adverse effects , Catheterization, Central Venous/adverse effects , Catheterization, Peripheral/adverse effects , Extravasation of Diagnostic and Therapeutic Materials/diagnosis , Extravasation of Diagnostic and Therapeutic Materials/therapy , Neoplasms/drug therapy , Antineoplastic Agents/therapeutic use , Dexrazoxane/therapeutic use , Dimethyl Sulfoxide/therapeutic use , Extravasation of Diagnostic and Therapeutic Materials/prevention & control , Humans , Hyaluronoglucosaminidase/therapeutic use , Quebec , Risk Factors , Thiosulfates/therapeutic use
10.
Curr Oncol ; 21(4): e630-41, 2014 Aug.
Article in English | MEDLINE | ID: mdl-25089112

ABSTRACT

BACKGROUND: Although antineoplastic agents are critical in the treatment of cancer, they can potentially cause hypersensitivity reactions that can have serious consequences. When such a reaction occurs, clinicians can either continue the treatment, at the risk of causing a severe or a potentially fatal anaphylactic reaction, or stop the treatment, although it might be the only one available. The objective of the present work was to evaluate the effectiveness of methods used to prevent and treat hypersensitivity reactions to platinum- or taxane-based chemotherapy and to develop evidence-based recommendations. METHODS: The scientific literature published to December 2013, inclusive, was reviewed. RESULTS: Premedication with antihistamines, H2 blockers, and corticosteroids is not effective in preventing hypersensitivity reactions to platinum salts. However, premedication significantly reduces the incidence of hypersensitivity to taxanes. A skin test can generally be performed to screen for patients at risk of developing a severe reaction to platinum salts in the presence of grade 1 or 2 reactions, but skin testing does not appear to be useful for taxanes. A desensitization protocol allows for re-administration of either platinum- or taxane-based chemotherapy to some patients without causing severe hypersensitivity reactions. CONCLUSIONS: Several strategies such as premedication, skin testing, and desensitization protocols are available to potentially allow for administration of platinum- or taxane-based chemotherapy to patients who have had a hypersensitivity reaction and for whom no other treatment options are available. Considering the available evidence, the Comité de l'évolution des pratiques en oncologie made recommendations for clinical practice in Quebec.

11.
Neuroscience ; 269: 343-66, 2014 Jun 06.
Article in English | MEDLINE | ID: mdl-24721734

ABSTRACT

Oligodendrocyte precursor cells (OPC) are glial cells that metamorphose into myelinating oligodendrocytes during embryogenesis and early stages of post-natal life. OPCs continue to divide throughout adulthood and some eventually differentiate into oligodendrocytes in response to demyelinating lesions. There is growing evidence that OPCs are also involved in activity-driven de novo myelination of previously unmyelinated axons and myelin remodeling in adulthood. In this review, we summarize the interwoven factors and cascades that promote the activation, recruitment and differentiation of OPCs into myelinating oligodendrocytes in the adult brain based mostly on results found in the study of demyelinating diseases. The goal of the review was to draw a complete picture of the transformation of OPCs into mature oligodendrocytes to facilitate the study of this transformation in both the normal and diseased adult brain.


Subject(s)
Brain/physiology , Myelin Sheath/physiology , Neural Stem Cells/physiology , Neuronal Plasticity/physiology , Oligodendroglia/physiology , White Matter/physiology , Animals , Brain/physiopathology , Demyelinating Diseases/physiopathology , Humans
12.
Ann Cardiol Angeiol (Paris) ; 62(5): 293-300, 2013 Nov.
Article in French | MEDLINE | ID: mdl-24054406

ABSTRACT

UNLABELLED: Heart failure (HF) complicating acute myocardial infarction (AMI) is of poor prognosis and is often associated with patient's characteristics and success of reperfusion strategies. However, few data is available regarding the high-risk subgroup of patients with anterior AMI treated successfully by primary angioplasty. The aim of the study was to assess the incidence, associated factors, and the future of HF occurring during hospitalisation, in the setting of anterior AMI treated successfully by primary angioplasty. METHODS: Eighty-five consecutive patients with anterior AMI treated successfully by primary angioplasty (final angiographic TIMI flow grade=3, without residual stenosis) were included. Clinical, biochemical, angiographic, and echocardiographic data were prospectively collected and compared between patients with (Killip 2 and 3) and without HF during hospitalisation. RESULTS: Fifteen patients had HF (18%) during hospitalisation and 70 did not. By comparison to patients without HF, patients with HF were more frequently diabetics, had troponin peak and CPK, leucocytes count, and fasting glucose higher, LVEF and wall motion score index in the left anterior descending territory (WMSi-lad) poorer, and a lower non-invasive coronary flow reserve (CFR) in the LAD 24hours after angioplasty (all, P<0.05). In multivariate analysis, fasting glucose, leucocytes count after angioplasty, CFR and WMSi-lad were independently associated with HF, even after adjusting with angiographic variables (all, P<0.05). At 6months, patients with HF had less recovery of LV function and higher frequency of adverse LV remodelling (58% versus 20%, P<0.01) by comparison to patients without HF. CONCLUSION: In conclusion, HF is not uncommon even after successful primary angioplasty for anterior AMI (nearly one patient out of 5), is associated with hyperglycaemia and inflammation, a poor microvascular reperfusion, and left ventricular systolic function, and is more frequently complicated by adverse LV remodelling and lack of LV recovery.


Subject(s)
Angioplasty, Balloon, Coronary , Heart Failure/complications , Myocardial Infarction/complications , Myocardial Infarction/therapy , Aged , Blood Glucose/analysis , Coronary Circulation/physiology , Female , Follow-Up Studies , Heart Failure/drug therapy , Heart Failure/mortality , Heart Failure/physiopathology , Hospitalization , Humans , Leukocyte Count , Male , Middle Aged , Multivariate Analysis , Prospective Studies , Stroke Volume/physiology , Systole/physiology , Ventricular Dysfunction, Left/physiopathology , Ventricular Remodeling/physiology
13.
Gynecol Obstet Fertil ; 41(7-8): 471-4, 2013.
Article in French | MEDLINE | ID: mdl-23867761

ABSTRACT

The combination of a colposcope to a computer with a 3D video adapter and a dedicated graphics card can get with a specialized 3D visualization deferred delayed colposcopic imaging software. The 3-dimensional images allow the observation of new aspects of epithelial surfaces from different angles which is possible to visualize with this technology alone.


Subject(s)
Colposcopy/instrumentation , Colposcopy/methods , Cervix Uteri/pathology , Epithelium/pathology , Female , Humans , Pregnancy , Software
14.
Nanotechnology ; 24(4): 045701, 2013 Feb 01.
Article in English | MEDLINE | ID: mdl-23291501

ABSTRACT

Dynamic and time-of-flight (TOF) secondary ion mass spectrometry (SIMS) was performed on vertically standing III-V nanowire ensembles embedded in Cyclotene polymer. By embedding the NWs in Cyclotene, the top surface of the sample was made planar, while the space between the NWs was filled to protect the background substrate from the ion beam, thus allowing for the NWs to be sputtered and analyzed evenly as a function of depth. Using thin film standards, SIMS analysis was used to calculate the impurity dopant concentration as a function of height in the NW ensemble. This marked the first use of conventional SIMS to accurately determine the doping density with excellent depth resolution. Additionally, this is the first presentation of SIMS as the only reported tool for characterizing the segment height uniformity of any arbitrary axial heterostructure NW ensemble.


Subject(s)
Materials Testing/methods , Nanotubes/chemistry , Nanotubes/ultrastructure , Spectrometry, Mass, Secondary Ion/methods
15.
Opt Express ; 20(3): 2081-95, 2012 Jan 30.
Article in English | MEDLINE | ID: mdl-22330449

ABSTRACT

Localization of single molecules in microscopy images is a key step in quantitative single particle data analysis. Among them, single molecule based super-resolution optical microscopy techniques require high localization accuracy as well as computation of large data sets in the order of 10(5) single molecule detections to reconstruct a single image. We hereby present an algorithm based on image wavelet segmentation and single particle centroid determination, and compare its performance with the commonly used gaussian fitting of the point spread function. We performed realistic simulations at different signal-to-noise ratios and particle densities and show that the calculation time using the wavelet approach can be more than one order of magnitude faster than that of gaussian fitting without a significant degradation of the localization accuracy, from 1 nm to 4 nm in our range of study. We propose a simulation-based estimate of the resolution of an experimental single molecule acquisition.


Subject(s)
Image Interpretation, Computer-Assisted/methods , Microscopy/methods , Molecular Imaging/methods , Nanoparticles/ultrastructure , Wavelet Analysis
16.
Ann Cardiol Angeiol (Paris) ; 60(5): 259-66, 2011 Nov.
Article in French | MEDLINE | ID: mdl-21903195

ABSTRACT

UNLABELLED: Left ventricular (LV) twist is increased in aortic stenosis (AS) and the hypothesis of a compensatory mechanism is suggested but not established. Our aim was to assess LV twist mechanics in severe AS (<1cm(2) or 0.6cm(2)/m(2)) with preserved LV ejection fraction (LVEF>50%), and to analyze its relationship with LV systolic longitudinal function, early impaired in this setting, LV diastolic function, and symptomatic status. METHODS: Forty-five consecutive patients with severe AS and preserved LVEF (mean age 73±11 years, 47% female, LVEF 68±11%, 67% symptomatic) underwent a transthoracic echocardiography including a bidimensional strain analysis by speckle tracking method, and were compared to a control group matched for age and sex (n=15). Global longitudinal strain (GLS) was measured using the four, two, and three apical views, and LV twist mechanics from the basal and apical short axis views. LV twist was defined as the net difference between apical and basal rotation, and LV twisting and untwisting rate (in°/s) were derived from twist curves. RESULTS: Peak apical rotation, LV twist (25±8° vs 20±6), as well as peak systolic and diastolic apical rotation rate, and peak LV twisting rate were significantly higher in patients with AS when compared to controls (all, P<0.05), whereas, the other parameters of LV twist mechanics including basal rotation, were not significantly different between groups. By contrast, the GLS was significantly lower in patients with AS when compared to controls (-17.9±4 vs -20.5±2%, P<0.01). In addition, the GLS was significantly correlated to LV torsion (r=-0.42, P<0.01). Moreover, LV twist progressively impaired with the worsening of diastolic dysfunction and with symptoms onset. CONCLUSION: LV twist is increased in severe AS with preserved LVEF, compensating the impairment of systolic longitudinal function. However, above a certain threshold LV twist deteriorates, attesting the failure of the compensatory mechanisms, leading to advanced diastolic dysfunction and symptom onset.


Subject(s)
Aortic Valve Stenosis/diagnostic imaging , Aortic Valve Stenosis/physiopathology , Echocardiography , Heart Ventricles/diagnostic imaging , Stroke Volume , Torsion Abnormality/diagnostic imaging , Ventricular Dysfunction, Left/diagnostic imaging , Aged , Aged, 80 and over , Algorithms , Case-Control Studies , Diastole , Echocardiography/methods , Female , Heart Ventricles/physiopathology , Humans , Male , Middle Aged , Observer Variation , Reference Values , Risk Assessment , Severity of Illness Index , Ventricular Dysfunction, Left/physiopathology
18.
Ann Cardiol Angeiol (Paris) ; 59(5): 263-70, 2010 Nov.
Article in French | MEDLINE | ID: mdl-20855057

ABSTRACT

OBJECTIVE: To assess the relationship between leukocyte count, non invasive coronary flow reserve (CFR), left ventricular systolic function, and in-hospital adverse events in acute anterior myocardial infarction (AMI) treated by primary angioplasty. METHODS: Leukocyte count at admission and within 24h after angioplasty, and differential count at admission were obtained in 72 consecutive patients with a first AMI (mean age 56±12 years) successfully treated by primary angioplasty. Transthoracic Doppler echocardiography was performed within 24h after angioplasty and 3 months later to assess the CFR (using intravenous adenosine), in the left anterior descending artery (LAD), left ventricular ejection fraction (LVEF) and the wall motion score index using the nine segments assigned to the LAD territory (WMSi-lad). In hospital events were defined as death, heart failure (Killip≥2) and reinfarction. RESULTS: Leukocyte count was higher before and after angioplasty in patients with impaired acute CFR (<1.7), when compared to patients without such impairment (P≤0.01), and a significant correlation was found between CFR and leukocyte, neutrophil and monocyte count (P<0.05). Leukocyte (before and after angioplasty), and neutrophil count, were lower in patients with recovery of global and regional LV function (P<0.05). A significant correlation was found between leukocyte count before and after angioplasty, and, initial and follow-up LVEF, and WMSi-lad (all, P≤0.01). Leukocyte (before and after angioplasty) and monocyte count were higher in patients with in-hospital events (n=14), by comparison to patients without events (all, P<0.01). In multivariate analysis, leukocyte count after angioplasty was an independent predictor of CFR, and in-hospital events, and neutrophil count of WMSi-lad at follow-up (all, P<0.05). CONCLUSION: In the first AMI treated successfully by primary angioplasty, leukocyte count is inversely correlated to CFR, and global and regional LV systolic function at follow-up. These links are higher after than before reperfusion. And, leukocyte count after angioplasty is an independent predictor of in-hospital adverse events.


Subject(s)
Angioplasty, Balloon, Coronary , Coronary Circulation , Hospitalization , Leukocytes/physiology , Myocardial Infarction/complications , Myocardial Infarction/therapy , Ventricular Function, Left , Female , Humans , Leukocyte Count , Male , Middle Aged , Myocardial Infarction/physiopathology , Prospective Studies , Systole
19.
J Gynecol Obstet Biol Reprod (Paris) ; 39(2): 102-15, 2010 Apr.
Article in French | MEDLINE | ID: mdl-20106606

ABSTRACT

OBJECTIVES: Analysis of the trials which compare the virologic testing (HPV testing) and the cytology in the cervical screening. MATERIAL AND METHODS: The MedLine database was consulted using the Keywords: "cervical screening", "pap smear", "liquid based cytology", "HPV testing", "adults", "adolescents", "cervical intraepithelial neoplasia (CIN)", "uterine cervix cancer". Articles were selected according their concern about the debate of the uterine cervix cancer screening in France. RESULTS: The HPV testing seems interesting allowing a decreasing delay in the diagnosis of CIN (more diagnosis of CIN2+ in the first round and less during the second one). But, when the two rounds are added, the number of CIN2+ are identical in the two arms (cytology and HPV testing) in all the trials (except the Italian NTCC trial). A negative HPV testing protects the women much longer than cytology can do: a delay of five years between two rounds seems ideal. The HPV testing alone increases the detection rate of cervical lesions, which could regress spontaneously and may induce an overtreatment, especially in the youngest population: a triage is necessary and the cytology appears to be the best way to select the candidates for colposcopy in case of positive HPV testing and cytology. The HPV infection presents some particularities in adolescent females: for this reason, the HPV testing should not be used in this special population. In vaccinated women, a consensus for the screening is necessary. CONCLUSION: The health care providers in France have to understand the characteristics of the HPV testing: its advantages compared to the cytologic screening are only evident in case of an organization of the screening in France and even in Europe.


Subject(s)
Mass Screening/methods , Papanicolaou Test , Papillomaviridae/isolation & purification , Uterine Cervical Neoplasms/diagnosis , Uterine Cervical Neoplasms/prevention & control , Vaginal Smears , Adolescent , Adult , Europe , Female , France , Humans , Mass Screening/economics , Papillomavirus Infections/diagnosis , Papillomavirus Infections/virology , Papillomavirus Vaccines , Randomized Controlled Trials as Topic , Time Factors , Uterine Cervical Neoplasms/virology , Uterine Cervical Dysplasia/diagnosis , Uterine Cervical Dysplasia/virology
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