350 research outputs found
Asymptotic expansions for the Laplace approximations for Itô functionals of Brownian rough paths
AbstractIn this paper, we establish asymptotic expansions for the Laplace approximations for Itô functionals of Brownian rough paths under the condition that the phase function has finitely many non-degenerate minima. Our main tool is the Banach space-valued rough path theory of T. Lyons. We use a large deviation principle and the stochastic Taylor expansion with respect to the topology of the space of geometric rough paths. This is a continuation of a series of papers by Inahama [Y. Inahama, Laplace's method for the laws of heat processes on loop spaces, J. Funct. Anal. 232 (2006) 148–194] and by Inahama and Kawabi [Y. Inahama, H. Kawabi, Large deviations for heat kernel measures on loop spaces via rough paths, J. London Math. Soc. 73 (3) (2006) 797–816], [Y. Inahama, H. Kawabi, On asymptotics of certain Banach space-valued Itô functionals of Brownian rough paths, in: Proceedings of the Abel Symposium 2005, Stochastic Analysis and Applications, A Symposium in Honor of Kiyosi Itô, Springer, Berlin, in press. Available at: http://www.abelprisen.no/no/abelprisen/deltagere_2005.html]
Burden of intracranial artery calcification in white patients with ischemic stroke
Introduction: The diagnostic workup of stroke doesn’t identify an underlying cause in two-fifths of ischemic strokes. Intracranial arteriosclerosis is acknowledged as a cause of stroke in Asian and Black populations, but is underappreciated as such in whites. We explored the burden of Intracranial Artery Calcification (IAC), a marker of intracranial arteriosclerosis, as a potential cause of stroke among white patients with recent ischemic stroke or TIA. Patients and methods: Between December 2005 and October 2010, 943 patients (mean age 63.8 (SD ± 14.0) years, 47.9% female) were recruited, of whom 561 had ischemic stroke and 382 a TIA. CT-angiography was conducted according to stroke analysis protocols. The burden of IAC was quantified on these images, whereafter we assessed the presence of IAC per TOAST etiology underlying the stroke and assessed associations between IAC burden, symptom severity, and short-term functional outcome. Results: IAC was present in 62.4% of patients. Furthermore, IAC was seen in 84.8% of atherosclerotic strokes, and also in the majority of strokes with an undetermined etiology (58.5%). Additionally, patients with larger IAC burden presented with heavier symptoms (adjusted OR 1.56 (95% CI [1.06–2.29]), but there was no difference in short-term functional outcome (1.14 [0.80–1.61]). Conclusion: IAC is seen in the majority of white ischemic stroke patients, aligning with findings from patient studies in other ethnicities. Furthermore, over half of patients with a stroke of undetermined etiology presented with IAC. Assessing IAC burden may help identify the cause in ischemic stroke of undetermined etiology, and could offer important prognostic information.</p
New Class of Monoclonal Antibodies against Severe Influenza: Prophylactic and Therapeutic Efficacy in Ferrets
Background: The urgent medical need for innovative approaches to control influenza is emphasized by the widespread resistance of circulating subtype H1N1 viruses to the leading antiviral drug oseltamivir, the pandemic threat posed by the occurrences of human infections with highly pathogenic avian H5N1 viruses, and indeed the evolving swine-origin H1N1 influenza pandemic. A recently discovered class of human monoclonal antibodies with the ability to neutralize a broad spectrum of influenza viruses (including H1, H2, H5, H6 and H9 subtypes) has the potential to prevent and treat influenza in humans. Here we report the latest efficacy data for a representative antibody of this novel class. Methodology/Principal Findings: We evaluated the prophylactic and therapeutic efficacy of the human monoclonal antibody CR6261 against lethal challenge with the highly pathogenic avian H5N1 virus in ferrets, the optimal model of human influenza infection. Survival rates, clinically relevant disease signs such as changes in body weight and temperature, virus replication in lungs and upper respiratory tract, as well as macro- and microscopic pathology were investigated. Prophylactic administration of 30 and 10 mg/kg CR6261 prior to viral challenge completely prevented mortality, weight loss and reduced the amount of infectious virus in the lungs by more than 99.9%, abolished shedding of virus in phar
Three-dimensional dento-skeletal effects of mandibular midline distraction and surgically assisted rapid maxillary expansion:A retrospective study
It was the aim of the study to provide a three-dimensional evaluation of dento-skeletal effects following bone-borne vs tooth-borne mandibular midline distraction (MMD) and tooth-borne surgically assisted rapid maxillary expansion (SARME). A retrospective observational study was conducted. Cone beam computed tomography (CBCT) records were taken pre-operatively (T1), immediately post-distraction (T2) and 1 year post-operatively (T3). All included 30 patients had undergone MMD (20 bone-borne MMD; 10 tooth-borne MMD). A total of 20 bone-borne MMD and 8 tooth-borne MMD patients had simultaneously undergone tooth-borne SARME. At T1 vs T3, canine (p = 0.007; 26.0 ± 2.09 vs 29.2 ± 2.02) and first premolar (p = 0.005; 33.8 ± 2.70 vs 37.0 ± 2.43) showed significant expansion on the tip level for tooth-borne MMD. This was no significant on the apex level, indicating tipping. Bone-borne MMD showed a parallel distraction gap, whereas tooth-borne MMD showed a V-shape. There was a significant (p = 0.017; 138 ± 17.8 vs 141 ± 18.2) inter-condylar axes increase for bone-borne MMD. In conclusion, bone-borne vs tooth-borne MMD and tooth-borne SARME showed stable dento-skeletal effects at 1 year post-operatively. Bone-borne and tooth-borne MMD seemed not to be superior to each other. The choice of distractor type therefore depends more on anatomical and comfort factors.</p
Hyoid bone morphology in patients with isolated robin sequence – A case-control study utilizing 3D morphable models
Background: Abnormalities of the hyoid bone are associated with impairment of oropharyngeal functions including feeding, swallowing, and breathing. Few studies have characterized anatomic abnormalities of the hyoid in patients with Robin sequence (RS), e.g. a less mineralized and voluminous hyoid. The purpose of this study was to compare normal hyoid bone morphology and hyoid bone morphology in children with isolated RS. Methods: Three-dimensional (3D) reconstructions of the hyoid bone were obtained from CT-imaging of children with RS and unaffected controls. A 3D morphable model was constructed using Principal Component Analysis (PCA). Partial least squares – Discriminant Analysis (PLS-DA) and multivariate analysis of variance (MANOVA) were used to characterize and compare hyoid shape differences between patients with RS and an age-matched control group. Results: The study included 23 subjects with RS (mean age 9.8 ± 10.3 months) and 46 age-matched control samples. A less voluminous hyoid was observed for the RS group with a larger lateral divergence of the greater horns compared to controls (MANOVA, p-value<0.001). The first shape variable from the PLS-DA model showed a significant correlation for the observed variance between the two groups (Spearman R = −0.56, p-value<0.001). The control samples and 151 CT-scans of subjects up to age 4 years were used to create a 3D morphable model of normal hyoid shape variation (n = 197, mean age 22.1 ± 13.1 months). For the normal 3D morphable model, a high degree of allometric shape variation was observed along the first principal component. Conclusions: The 3D morphable models provide a comprehensive and quantitative description of variation in normal hyoid bone morphology, and allow detection of distinct differences between patients with isolated RS and controls.</p
Hyoid bone morphology in patients with isolated robin sequence – A case-control study utilizing 3D morphable models
Background: Abnormalities of the hyoid bone are associated with impairment of oropharyngeal functions including feeding, swallowing, and breathing. Few studies have characterized anatomic abnormalities of the hyoid in patients with Robin sequence (RS), e.g. a less mineralized and voluminous hyoid. The purpose of this study was to compare normal hyoid bone morphology and hyoid bone morphology in children with isolated RS. Methods: Three-dimensional (3D) reconstructions of the hyoid bone were obtained from CT-imaging of children with RS and unaffected controls. A 3D morphable model was constructed using Principal Component Analysis (PCA). Partial least squares – Discriminant Analysis (PLS-DA) and multivariate analysis of variance (MANOVA) were used to characterize and compare hyoid shape differences between patients with RS and an age-matched control group. Results: The study included 23 subjects with RS (mean age 9.8 ± 10.3 months) and 46 age-matched control samples. A less voluminous hyoid was observed for the RS group with a larger lateral divergence of the greater horns compared to controls (MANOVA, p-value<0.001). The first shape variable from the PLS-DA model showed a significant correlation for the observed variance between the two groups (Spearman R = −0.56, p-value<0.001). The control samples and 151 CT-scans of subjects up to age 4 years were used to create a 3D morphable model of normal hyoid shape variation (n = 197, mean age 22.1 ± 13.1 months). For the normal 3D morphable model, a high degree of allometric shape variation was observed along the first principal component. Conclusions: The 3D morphable models provide a comprehensive and quantitative description of variation in normal hyoid bone morphology, and allow detection of distinct differences between patients with isolated RS and controls.</p
Sustained Delivery of Insulin-Like Growth Factor-1/Hepatocyte Growth Factor Stimulates Endogenous Cardiac Repair in the Chronic Infarcted Pig Heart
Activation of endogenous cardiac stem/progenitor cells (eCSCs) can improve cardiac repair after acute myocardial infarction. We studied whether the in situ activation of eCSCs by insulin-like growth factor 1 (IGF-1) and hepatocyte growth factor (HGF) could be increased using a newly developed hydrogel in chronic myocardial infarction (MI). One-month post-MI pigs underwent NOGA-guided intramyocardial injections of IGF-1/HGF (GF: both 0.5 μg/mL, n = 5) or IGF-1/HGF incorporated in UPy hydrogel (UPy-GF; both 0.5 μg/mL, n = 5). UPy hydrogel without added growth factors was administered to four control (CTRL) pigs. Left ventricular ejection fraction was increased in the UPy-GF and GF animals compared to CTRLs. UPy-GF delivery reduced pathological hypertrophy, led to the formation of new, small cardiomyocytes, and increased capillarization. The eCSC population was increased almost fourfold in the border zone of the UPy-GF-treated hearts compared to CTRL hearts. These results show that IGF-1/HGF therapy led to an improved cardiac function in chronic MI and that effect size could be further increased by using UPy hydrogel. Electronic supplementary material The online version of this article (doi:10.1007/s12265-013-9518-4) contains supplementary material, which is available to authorized users
Balancing Benefits and Risks of Long-Term Antiplatelet Therapy in Noncardioembolic Transient Ischemic Attack or Stroke
Lifelong treatment with antiplatelet drugs is recommended following a transient ischemic attack or ischemic stroke. Bleeding complications may offset the benefit of antiplatelet drugs in patients at increased risk of bleeding and low risk of recurrent ischemic events. We aimed to investigate the net benefit of antiplatelet treatment according to an individuals’ bleeding risk. METHODS: We pooled individual patient data from 6 randomized clinical trials (CAPRIE [Clopidogrel Versus Aspirin in Patients at Risk of Ischemic Events], ESPS-2 [European Stroke Prevention Study-2], MATCH [Management of Atherothrombosis With Clopidogrel in High-Risk Patients], CHARISMA [Clopidogrel for High Atherothrombotic Risk and Ischemic Stabilization, Management, and Avoidance], ESPRIT [European/Australasian Stroke Prevention in Reversible Ischemia Trial], and PRoFESS [Prevention Regimen for Effectively Avoiding Second Strokes]) investigating antiplatelet therapy in the subacute or chronic phase after noncardioembolic transient ischemic attack or stroke. Patients were stratified into quintiles according to their predicted risk of major bleeding with the S(2)TOP-BLEED score. The annual risk of major bleeding and recurrent ischemic events was assessed per quintile for 4 scenarios: (1) aspirin monotherapy, (2) aspirin-clopidogrel versus aspirin or clopidogrel monotherapy, (3) aspirin-dipyridamole versus clopidogrel, and (4) aspirin versus clopidogrel. Net benefit was calculated for the second, third, and fourth scenario. RESULTS: Thirty seven thousand eighty-seven patients were included in the analyses. Both risk of major bleeding and recurrent ischemic events increased over quintiles of predicted bleeding risk, but risk of ischemic events was consistently higher (eg, from 0.7%/y (bottom quintile) to 3.2%/y (top quintile) for major bleeding on aspirin and from 2.5%/y to 10.2%/y for risk of ischemic events on aspirin). Treatment with aspirin-clopidogrel led to more major bleedings (0.9%–1.7% per year), than reduction in ischemic events (ranging from 0.4% to 0.9/1.0% per year) across all quintiles. There was no clear preference for either aspirin-dipyridamole or clopidogrel according to baseline bleeding risk. CONCLUSIONS: Among patients with a transient ischemic attack or ischemic stroke included in clinical trials of antiplatelet therapy, the risk of recurrent ischemic events and of major bleeding increase in parallel. Antiplatelet treatment cannot be individualized solely based on bleeding risk assessment
Atrial fibrillation in a primary care practice: prevalence and management
BACKGROUND: Atrial fibrillation is a common serious cardiac arrhythmia. Knowing the prevalence of atrial fibrillation and documentation of medical management are important in the provision of primary care. This study sought to determine the prevalence of atrial fibrillation in a primary care population and to identify and quantify the treatments being used for stroke prevention in this group of patients. METHODS: A prevalence study through chart audit was conducted in the family medicine practice at the Sunnybrook campus of the Sunnybrook and Women's College Health Sciences Centre. The main outcome measures were the prevalence of atrial fibrillation in our primary care practice and the use of warfarin for stroke prevention in this population. RESULTS: 261 patients in our practice have atrial fibrillation. The overall prevalence in our family practice unit is 3.9%. When considering patients aged 60 and over, the prevalence rises to 12.2%. 204 of our patients with atrial fibrillation (78.2%) are currently being treated with warfarin. Another 21 patients were previously treated and discontinued for a number of reasons. Of the 57 patients not currently treated with warfarin, 44 are treated with ASA, 2 with ticlopidine, and 11 are receiving no preventative treatment. CONCLUSIONS: The prevalence of atrial fibrillation in our practice is higher than the range of prevalence reported in the general literature. However, our coverage with warfarin treatment exceeds previous reports in the literature
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